CN100451725C - Mirror device, mirror array, optical switch, and manufacturing method thereof - Google Patents
Mirror device, mirror array, optical switch, and manufacturing method thereof Download PDFInfo
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- CN100451725C CN100451725C CNB2005800196251A CN200580019625A CN100451725C CN 100451725 C CN100451725 C CN 100451725C CN B2005800196251 A CNB2005800196251 A CN B2005800196251A CN 200580019625 A CN200580019625 A CN 200580019625A CN 100451725 C CN100451725 C CN 100451725C
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Abstract
A mirror (153) turnably supported on a mirror substrate (151), driving electrodes (103-1 to 103-4) formed on an electrode substrate (101) facing the mirror substrate, and an antistatic structure (106) arranged in a space between the mirror and the electrode substrate are provided. Thus, a potential of a lower plane of the mirror can be fixed by giving a second potential to the antistatic structure, and a drift of the mirror can be suppressed.
Description
Technical field
The present invention relates to a kind of static driven mirror device with the catoptron at variable tilted angle, a kind of reflection mirror array with a plurality of mirror devices of two-dimensional arrangement, a kind ofly have the photoswitch of this reflection mirror array, a kind of method of making this mirror device, and a kind of method of making mirror substrate included in this mirror device.
Background technology
As the hardware technology that realizes extensive photoswitch, MEMS (micro electro mechanical system) (MEMS) photoswitch has been subjected to extensive attention.The tool characteristic of mems optical switch is the MEMS reflection mirror array.The MEMS reflection mirror array comprises a plurality of MEMS mirror devices (following will be called mirror device) of two-dimensional arrangement.Conventional mirror device (for example seeing Jap.P. No.3579015) below will be described.
Shown in Figure 107 and 108, the insulation course of being made by silicon oxide film 8002 is formed on the infrabasal plate 8001 of monocrystalline silicon.Four drive electrode 8003-1 to 8003-4 are set on the insulation course 8002 of substrate 8001 centers.The pillar 8004 of monocrystalline silicon is set at the both sides of infrabasal plate 8001 upper surfaces.
Annular gimbals (annular gimbal) 8102 are arranged in the upper substrate 8101.Catoptron 8103 is set in the gimbals 8102.For example, Ti/Pt/Au (titanium/platinum/gold) the layer (not shown) with three-decker is formed on the upper surface of catoptron 8103.Torsion spring (torsionsprings) 8104 is connected to gimbals 8102 at two 180 ° of corresponding points with upper substrate 8101.Similar, torsion spring 1805 is connected to catoptron 8103 at two 180 ° of corresponding points with gimbals 8102.By this to the X-axis of torsion spring 8104 and by this to the Y-axis of torsion spring 8105 with right angle intersection.As a result, catoptron 8103 can rotate around X and Y-axis, and each of X and Y-axis all is used as turning axle.Upper substrate 8101, gimbals 8102, catoptron 8103 and torsion spring 8104 and 8105 are made by monocrystalline silicon integratedly.
Separately make the structure of the infrabasal plate 8001 shown in Figure 107 and 108 and the structure of upper substrate 8101.Upper substrate 8101 is welded on the pillar 8004, makes upper substrate 8101 join on the infrabasal plate 8001.In this mirror device, make catoptron 8103 ground connection.8003-1 to 8003-4 applies positive voltage to drive electrode, so that produce asymmetric electric potential difference between drive electrode 8003-1 to 8003-4.Electrostatic force attracts catoptron 8103, and make its above arbitrarily to rotation.
Wherein drive electrode 8003-1 to 8003-4 produce electrostatic force with the design of the mirror device that drives catoptron 8103 based on the following fact: the third power that is different from size is proportional gravity of volume or inertial force, and the second power of electrostatic force and size is that area is proportional.For common centimetre magnitude, only in several kilovolts or more high-tension triboelectricity, electrostatic force exists and is only significantly.Along with size reduces, the third power of inertial force and size sharply diminishes pro rata.Yet the second power of electrostatic force and size reduces pro rata.Therefore, in microworld, even lie prostrate under tens volts the low pressure several, electrostatic force also may lift or mobile object.In the mirror device shown in Figure 107 and 108, the diameter of catoptron 8103 for example is approximately 500 μ m.Distance between catoptron 8103 and the drive electrode 8003-1 to 8003-4 for example is approximately 90 μ m.
Triboelectricity is owing to its high voltage causes spark discharge.Yet, in the small reflector device, under identical electric field intensity, the snowslide spark discharge does not take place.This be because, because the distance between catoptron 8103 and the drive electrode 8003-1 to 8003-4 is short, even when electric-field strength, the particle that is quickened by this electric field (for a certain reason and the particle of ionization, for example in the air by the ion of cosmic rays or natural radiation ionization) can not obtain sufficiently high energy so that Peng Zhuan other neutral particle ionization with it.(in this mirror device, being between catoptron 8103 and the drive electrode 8003-1 to 8003-4) electric field intensity is proportional between electrostatic force and electrode.Therefore, if interelectrode distance is long, then must between electrode, provide big voltage difference.Yet, as mentioned above, put on interelectrode big voltage difference and may cause discharge.In the small reflector device,, put on interelectrode voltage difference and also can reduce pro rata with interelectrode distance even under identical electric field intensity.Because above-mentioned factor has prevented discharge, so can obtain stable driving force.The main reason that electrostatic force is used as effectively the driving force in the mirror device has more than been described.Use electrostatic force to allow to come controlling and driving power by the voltage that puts on drive electrode 8003-1 to 8003-4.Because it is easy controlling by electronic circuit, and there is not the electric current of any steady flow, so power consumption greatly reduces.
Summary of the invention
The problem to be solved in the present invention
Because the size of mirror device is little, think that the absolute value that drives the required power of catoptron 8103 is little.When inertial force when the driving force, for the absolute value that drives the required power of catoptron 8103 will reduce suddenly pro rata with the third power of size.Though with compare for the absolute value that drives the required power of catoptron 8103, electrostatic force is bigger, electrostatic force also reduces pro rata with the second power of size.Be subjected to the influence of the small electrostatic force of negligible accident under stock size easily with the mirror device of very little power operation.
Exemplary is the drift phenomenon that throws into question in the MEMS of static driven mirror device.Drift has indicated the tiltangle of catoptron 8103 from the displacement by the suitable angle that voltage determined that puts on drive electrode 8003-1 to 8003-4.Those skilled in the art know drifting problem already, and it is relevant with charge movement to have understood the reason of drift.That is, between the generation of drift and the electrode or the charging of another stray capacitance or near the required time of electrifying the electrode relevant.Yet therefore concrete mechanism the unknown of drift, can only take measures to prevent to experience drift.That is, measure may effectively maybe may not imitated, and is difficult to establish a kind of practicable method.
The means of dealing with problems
Consider above-mentioned traditional problem and proposed the present invention, the objective of the invention is the drift of inhibitory reflex mirror.
Another object of the present invention is that a kind of mirror device manufacture method that can make the catoptron with expectation amount of bow is provided.
Another purpose of the present invention is to form mirror substrate with high zero defect unit output.
Another purpose of the present invention is to realize that low voltage drive and cost reduce, and increase the angle of rotation of catoptron.
In order to realize above purpose, according to the present invention, provide a kind of mirror device, it is characterized in that comprising: being supported for can be with respect to the catoptron of mirror substrate rotation; Be formed in the face of the drive electrode on the electrode base board of mirror substrate; And be disposed in antistatic structure in the gap between catoptron and the electrode base board.
According to the present invention, a kind of reflection mirror array also is provided, it is characterized in that having arranged a plurality of mirror devices two-dimensionally that each of these mirror devices all comprises: being supported for can be with respect to the catoptron of mirror substrate rotation; Be formed in the face of the drive electrode on the electrode base board of mirror substrate; And be disposed in antistatic structure in the gap between catoptron and the electrode base board.
According to the present invention, a kind of photoswitch also is provided, it is characterized in that comprising: reflection is from first reflection mirror array of the light of input port; And reflect from the light of first reflection mirror array and with second reflection mirror array of photoconduction to output port, each of first reflection mirror array and second reflection mirror array all comprises a plurality of above-mentioned mirror device of two-dimensional arrangement.
According to the present invention, a kind of mirror device manufacture method also is provided, this mirror device comprises the mirror substrate with the plane mirror (flat mirror) that supports rotationally, and the electrode base board that is used to control the electrode that this catoptron rotates in the face of this mirror substrate and having, this mirror device manufacture method is characterised in that and comprises: first step, prepare to have the mirror substrate of the plane mirror of support rotationally; Second step forms the first metal layer on a surface of catoptron; Third step forms second metal level on another surface of catoptron; And the 4th step, mirror substrate is placed on the electrode base board, so that electrode surface is to catoptron.
According to the present invention, a kind of mirror substrate manufacture method also is provided, it is characterized in that comprising at least: first step, prepare the SOI substrate, this SOI substrate comprises the buried insulating layer on baseplate part, the baseplate part, and the silicon layer on the buried insulating layer; Second step, on the surface of silicon layer, form movable part and form mask pattern, and by this movable part formation mask pattern is carried out etching as mask, form this silicon layer, so that the catoptron on buried insulating layer forms in the district, the tabular mirror structure that forms base portion and be connected to this base portion by a pair of connecting portion; Third step forms the protective seam of filling the gap between base portion, connecting portion and the mirror structure; And the 4th step, on the surface of baseplate part, form and have the framework formation mask pattern that forms district's corresponding opening with catoptron, and by this framework formation mask pattern is carried out etching as mask, remove baseplate part and buried insulating layer, expose so that catoptron forms the silicon layer of that side of baseplate part in the district, and form frame section in outside, catoptron formation district.
According to the present invention, a kind of mirror device manufacture method also is provided, this mirror device comprises the mirror substrate with the catoptron that supports rotationally, and the electrode base board of facing this mirror substrate, this mirror device manufacture method is characterised in that and comprises: first step, prepare electrode base board, the conical teat of cardinal principle that this electrode base board has the plane, stretch out from this plane and be formed on groove the plane around this teat; Second step on the surface of this plane of electrode base board and teat and groove, forms metal level; Third step carries out patterning to metal level, and the focus with exposure sources is located on this plane simultaneously, so that form distribution on the surface of on this plane and at least this teat and groove, and forms the electrode that is connected to this distribution; And the 4th step, mirror substrate is placed on the electrode base board, so that electrode surface is to catoptron.
Effect of the present invention
Effect of the present invention is the drift of inhibitory reflex mirror.Because antistatic structure is arranged in the gap between catoptron and the infrabasal plate,, perhaps can have the part of big charge constant from removing near the drive electrode so the charge constant of the part relevant with mirror drive can be little.
According to the present invention, because metal level not only is set on surface of catoptron, and be set on another surface of catoptron, so can control the bending of catoptron.
According to the present invention, when on buried insulating layer, forming base portion, connecting portion and mirror structure, formed the protective seam of filling the gap between them.Even form buried insulating layer in the district, so that the two sides of silicon layer all exposes and when making mirror structure removable, prevented that also mirror structure from moving when removing catoptron.As a result, according to the present invention, can prevent that mirror structure and connecting portion from damaging.This permission forms mirror substrate with high zero defect unit output.
According to the present invention, because in base portion, formed teat in the formed groove, to increase the difference of elevation of teat, so catoptron can have big angle of rotation.Distribution is formed on the base portion, and electrode is formed on formed groove in the substrate and the teat that stretches out from this groove on.Therefore, the focus of exposure sources is located on the upper surface of base portion, allows to form distribution and electrode with required precision.
Description of drawings
Fig. 1 is the decomposition diagram according to the mirror device of first embodiment of the invention;
Fig. 2 is the sectional view according to the mirror device of first embodiment of the invention;
Fig. 3 is the equivalent circuit diagram of the circuit relevant with mirror drive in the mirror device;
Fig. 4 is the sectional view according to the mirror device of second embodiment of the invention;
Fig. 5 is the sectional view according to the mirror device of third embodiment of the invention;
Fig. 6 is the sectional view according to the mirror device of four embodiment of the invention;
Fig. 7 is the sectional view according to the major part of the mirror device of fifth embodiment of the invention;
Fig. 8 is the decomposition diagram that illustrates according to the structure of the mirror device of sixth embodiment of the invention;
Fig. 9 is the sectional view of the major part of mirror device shown in Figure 8;
Figure 10 is the sectional view according to the mirror device of seventh embodiment of the invention;
Figure 11 is the perspective illustration that conventional mirror substrate and electrode base board structure are shown;
Figure 12 is the perspective illustration that the conventional mirror device architecture is shown;
Figure 13 is the sectional view of mirror device shown in Figure 12;
Figure 14 is the skeleton view that illustrates according to the electrode base board structure of the reflection mirror array of the 8th embodiment;
Figure 15 illustrates according to the mirror substrate of the 8th embodiment and the perspective illustration of electrode base board structure;
Figure 16 A is the sectional view of being got along the line I-I among Figure 16 B;
Figure 16 B is the planimetric map according to the mirror device of eighth embodiment of the invention;
Figure 17 A to 17D is the view that illustrates according to a kind of manufacture method of the electrode base board of the 8th embodiment;
Figure 18 A to 18C is the view that illustrates according to a kind of manufacture method of the electrode base board of the 8th embodiment;
Figure 19 A to 19C is the view that illustrates according to a kind of manufacture method of the electrode base board of the 8th embodiment;
Figure 20 A to 20F is the view that illustrates according to a kind of manufacture method of the electrode base board of the 8th embodiment;
Figure 21 is the sectional view that illustrates according to a kind of modification of the electrode base board of the 8th embodiment;
Figure 22 is the sectional view that illustrates according to a kind of modification of the electrode base board of the 8th embodiment;
Figure 23 is the synoptic diagram that traditional photoswitch is shown;
Figure 24 is the sectional view that diagram illustrates the structure of traditional reflective lens array;
Figure 25 A is the schematic section that illustrates according to the structure of the reflection mirror array of the 9th embodiment;
Figure 25 B is the schematic plan view that illustrates according to the structure of the reflection mirror array of the 9th embodiment;
Figure 26 is the schematic section that the structure of conventional mirror device is shown;
Figure 27 is the schematic section that illustrates according to the structure of the mirror device of the 9th embodiment;
Figure 28 is the schematic plan view that illustrates according to the structure of the reflection mirror array of the 9th embodiment;
Figure 29 is the synoptic diagram that illustrates according to the structure of the photoswitch of the 9th embodiment;
Figure 30 is the synoptic diagram that illustrates according to the cross section of the reflection mirror array of the 9th embodiment;
Figure 31 is the schematic plan view that illustrates according to the mirror device of the tenth embodiment;
Figure 32 is the synoptic diagram that the torsion spring structure is shown;
Figure 33 B is the synoptic diagram that the torsion spring structure is shown;
Figure 33 A is the curve map that the spring constant of the torsion spring shown in Figure 33 B is shown;
Figure 34 B is the synoptic diagram that the torsion spring structure is shown;
Figure 34 A is the curve map of the spring constant of the torsion spring shown in Figure 34 B;
Figure 35 is the schematic section that the structure of conventional mirror device is shown;
Figure 36 is the schematic section that illustrates according to the structure of the mirror device of the tenth embodiment;
Figure 37 is the schematic plan view that illustrates according to the structure of the reflection mirror array of the tenth embodiment;
Figure 38 is the schematic plan view that the modification of mirror substrate is shown;
Figure 39 A is the schematic section that illustrates according to the mirror device of the 11 embodiment;
Figure 39 B is the schematic plan view that illustrates according to the mirror device of the 11 embodiment;
Figure 40 is the schematic section that the structure of conventional mirror device is shown;
Figure 41 is the schematic section that illustrates according to the structure of the mirror device of the 11 embodiment;
Figure 42 is the schematic plan view that illustrates according to the structure of the reflection mirror array of the 11 embodiment;
Figure 43 is the skeleton view that illustrates according to the structure of the mirror device of the 12 embodiment;
Figure 44 is the schematic section that illustrates according to the structure of the mirror device of the 12 embodiment;
Figure 45 is the schematic plan view according to the mirror device of the 13 embodiment;
Figure 46 is the schematic section of conventional mirror device;
Figure 47 is the schematic section according to the mirror device of the 13 embodiment;
Figure 48 is the schematic plan view according to another mirror device of the 13 embodiment;
Figure 49 is the schematic plan view according to the another mirror device of the 13 embodiment;
Figure 50 is the schematic plan view according to the another mirror device of the 13 embodiment;
Figure 51 is the schematic plan view according to the reflection mirror array of the 13 embodiment;
Figure 52 is the decomposition diagram that illustrates according to the structure of the mirror device of the 14 embodiment;
Figure 53 is the sectional view of mirror device shown in Figure 52;
Figure 54 illustrates from the electrostatic force of the distribution curve map to the actual measured results of the influence of catoptron 1103;
Figure 55 is the process that is used for illustrating measuring data shown in Figure 54, the view of the arrangement condition of catoptron 1103, drive electrode 1003-1 to 1003-4 and distribution;
Figure 56 is the planimetric map that illustrates according to the layout of mirror device in the reflection mirror array of the 15 embodiment and distribution;
Figure 57 is the decomposition diagram that illustrates according to the structure of the mirror device of the 16 embodiment;
Figure 58 is the sectional view that mirror device shown in Figure 57 is shown;
Figure 59 is the view that is used for illustrating the principle of the mirror tilt angle variation that suppresses the 16 embodiment;
Figure 60 is the sectional view that illustrates according to the structure of the major part of the mirror device of the 17 embodiment;
Figure 61 is the sectional view that illustrates according to the structure of the major part of the mirror device of the 18 embodiment;
Figure 62 is the decomposition diagram that the structure of conventional mirror device is shown;
Figure 63 is the sectional view that mirror device shown in Figure 62 is shown;
Figure 64 illustrates the driving voltage in the mirror device shown in Figure 62 to the curve map of the characteristic example in pitch angle;
Figure 65 illustrates driving voltage when the catoptron in the mirror device shown in Figure 62 sinks and rotates to the curve map of the characteristic example in pitch angle;
Figure 66 is the decomposition diagram that illustrates according to the structure of the mirror device of the 19 embodiment;
Figure 67 is the sectional view that mirror device shown in Figure 66 is shown;
Figure 68 is the view that is used to illustrate according to the bias voltage applying method of the 19 embodiment;
Figure 69 is the view of the catoptron that is used for illustrating the 19 embodiment voltage application method when rotating;
Figure 70 illustrates according to the curve map of the driving voltage in the mirror device of the 19 embodiment to the characteristic example in pitch angle;
Figure 71 is used for illustrating that the 19 embodiment applies the view of the effect of bias voltage to drive electrode;
Figure 72 is the view that is used for illustrating the driving method that twin shaft drives;
Figure 73 is the view that is used to illustrate the bias voltage establishing method;
Figure 74 is the curve map that concerns between driving voltage when bias voltage being shown changing and the pitch angle;
Figure 75 is the perspective diagram that illustrates according to the configuration example of the mirror device of the 20 embodiment;
Figure 76 A to 76L is illustrated in the view of manufacturing according to the example of the step in the mirror substrate process of the 20 embodiment;
Figure 77 is the schematic plan view that illustrates according to the configuration example of the mirror substrate of the 20 embodiment;
Figure 78 is that part illustrates the perspective diagram according to the configuration example of the mirror substrate of the 20 embodiment;
Figure 79 is that part illustrates the perspective diagram according to the configuration example of the mirror substrate of the 20 embodiment;
Figure 80 is that diagram illustrates the planimetric map according to the configuration example of the mirror substrate of the 20 embodiment;
Figure 81 is that diagram illustrates the planimetric map according to the configuration example of the mirror substrate of the 20 embodiment;
Figure 82 is the sectional view that illustrates according to the structure of the mirror device of the 21 embodiment;
Figure 83 is the skeleton view that illustrates according to the structure of the mirror device of the 21 embodiment;
Figure 84 A to 84E is used for explanation, the view of the example of the step in the mirror device of making according to the 21 embodiment in the included mirror substrate process;
Figure 85 A to 85E is used for explanation, the view of the example of the step in the mirror device of making according to the 21 embodiment in the included mirror substrate process;
Figure 86 is the sectional view that the configuration example of conventional mirror device is shown;
Figure 87 is the sectional view that the configuration example of conventional mirror device is shown;
Figure 88 is the planimetric map that is used to illustrate according to the structure of the mirror substrate of the 22 embodiment;
Figure 89 is the skeleton view that the torsion spring that forms removable framework connecting portion and catoptron connecting portion is shown;
Figure 90 is the planimetric map that is used to illustrate according to the structure of the mirror substrate of the 22 embodiment;
Figure 91 is the skeleton view that traditional photoswitch is shown;
Figure 92 is the view that is used to illustrate the problem of traditional photoswitch;
Figure 93 is the skeleton view that illustrates according to the structure of the photoswitch of the 23 embodiment;
Figure 94 is the decomposition diagram of mirror device included in the photoswitch according to the 23 embodiment;
Figure 95 illustrates according to the 23 embodiment, the view of the relation between the layout district of the drive electrode layout of the mirror device of input end reflection mirror array and the mirror device of output end mirror array;
Figure 96 is the sectional view that illustrates according to the mirror device of the 24 embodiment, and wherein drive electrode is formed on the step teat of infrabasal plate;
Figure 97 is a kind of like this sectional view of mirror device, and wherein drive electrode is formed on the conical teat of infrabasal plate;
Figure 98 is the skeleton view of step teat;
Figure 99 is formed separately the skeleton view of four drive electrodes on the step teat;
Figure 100 A is the schematic plan view that illustrates according to the mirror structure of the mirror device in the reflection mirror array of the 25 embodiment;
Figure 100 B is the side view according to the catoptron of the 25 embodiment;
Figure 100 C is the backplan according to the catoptron of the 25 embodiment;
Figure 101 A illustrates the deposition of gold thickness of the catoptron 230 that has only upper surface layer 232 and the curve map of the relation between the catoptron amount of bow;
Figure 101 B illustrates the deposition of gold thickness of the catoptron 230 that has only upper surface layer 232 and the curve map of the relation between the catoptron amount of bow;
Figure 102 A illustrates catoptron 230 so that the schematic section of the bending of explanation catoptron 230;
Figure 102 B illustrates catoptron 230 so that the schematic section of the bending of explanation catoptron 230;
Figure 102 C illustrates catoptron 230 so that the schematic section of the bending of explanation catoptron 230;
Figure 103 A to 103E is used for illustrating at the synoptic diagram of manufacturing according to the step of the mirror substrate process of the reflection mirror array of the 25 embodiment;
Figure 104 A to 104C is the synoptic diagram that is used to illustrate the bending of catoptron 230;
Figure 105 A to 105K is illustrated in the view of formation according to the step in the mirror substrate process of the 28 embodiment;
Figure 106 is that diagram illustrates the skeleton view by the structure of the formed mirror substrate 2300 of the step among Figure 105 A to 105K;
Figure 107 is the decomposition diagram that the structure of conventional mirror device is shown; And
Figure 108 is the sectional view of mirror device shown in Figure 107.
Embodiment
Describe embodiment of the present invention in detail below with reference to accompanying drawing.
[first embodiment]
In the present embodiment, the lip-deep insulation course 102 of each pillar 104 is partly removed, to form contact hole 106.The metal level of being made by for example Au 105 is formed on the contact hole 106.
In the present embodiment, the metal level 156 made and be used as antistatic structure by for example Au is formed on the lower surface of upper substrate 151, gimbals 152, catoptron 153 and torsion spring 154 and 155.
Because the surface planarity of catoptron 153 requires and the reliability requirement of torsion spring 154 and 155, so the general use of mirror device can obtain silicon-on-insulator (SOI) substrate of monocrystalline silicon easily, and especially used thickness is approximately the monocrystalline silicon plate of 10 μ m.Catoptron 153 is formed on the SOI substrate.Make catoptron 153 in the face of drive electrode 103-1 to 103-4, utilize as the scolder of golden tin (AuSn) alloy or, metal level 105 is bonded on the metal level 156, make upper substrate 151 be bonded on the infrabasal plate 101 as the electroconductive binder of elargol.
In this mirror device, make catoptron 153 ground connection.Apply positive voltage or negative voltage to drive electrode 103-1 to 103-4, so that between drive electrode 103-1 to 103-4, produce asymmetric electric potential difference.Electrostatic force attracts catoptron 153, and makes it go up rotation in any direction.
Next, will the conventional mirror device shown in Figure 107 and 108 be described by way of example, be described with reference to Figure 3 the reason of catoptron drift.
With reference to figure 3, Reference numeral R1 represents the stake resistance of catoptron 8103; R2 is illustrated in the resistance of formed insulation course on drive electrode 8003-1 to the 8003-4 surface (not shown among Figure 107 and 108); R3 represents the stake resistance of infrabasal plate 8001; R4 represents, when leakage current by insulation course 8002, from drive electrode 8003-1 to 8003-4 and the insulation leakagel volume leakage resistance of distribution (Figure 107 and 108 not shown) when flowing to infrabasal plate 8001 that be used for providing the first electromotive force V (V 〉=0 in the present embodiment) to electrode; C1 is illustrated in the electric capacity that forms between catoptron 8103 and the drive electrode 8003-1 to 8003-4; C2 is illustrated in the electric capacity of formed insulation course on drive electrode 8003-1 to the 8003-4 surface; C3 is illustrated in infrabasal plate 8001 and drive electrode 8003-1 to 8003-4 and is used for providing formed distribution stray capacitance (electric capacity of insulation course 8002) between the distribution of first electromotive force to electrode; REG represents power supply, and it applies first electromotive force by distribution to drive electrode 8003-1 to 8003-4, and applies second electromotive force (second electromotive force equals or is different from first electromotive force, and is earth potential in the present embodiment) to catoptron 8103 and infrabasal plate 8001.
The drift of catoptron 8103 can be divided into roughly two types.When being defective when making voltage between catoptron 8103 and the drive electrode 8003-1 to 8003-4 not follow the voltage that puts on electric distribution owing to the distribution that is used for applying voltage between catoptron 8103 and drive electrode 8003-1 to 8003-4, first type drift takes place.When in case apply voltage, have the just polarization of electric spurious portion of uncertain electromotive force, cause for a certain reason and electrify gradually, perhaps lose charges accumulated gradually and when influencing the driving force of catoptron 8103, second type drift takes place.Another example of the part that this polarization takes place or electrify is the part that is connected to first electromotive force or second electromotive force with high resistance.
That is, when the charge constant in the part relevant with the driving of catoptron 8103 (near the structure catoptron 8103, drive electrode 8003-1 to 8003-4 and the drive electrode 8003-1 to 8003-4) is big, to drift about basically.Can utilize two kinds of measures to suppress drift.A kind of measure is to reduce the charge constant.Another kind of measure is the part that has big charge constant near the removal of drive electrode 8003-1 to 8003-4.
Make in the mirror device of beam deflection by utilizing electrostatic force that catoptron 8103 is rotated, the micro-displacement at the pitch angle of catoptron 8103 is enlarged into the displacement of light beam projecting point.Therefore, the drift of catoptron 8103 is minimized.Especially in the spatial optical switches of using mirror device, the displacement at catoptron 8103 pitch angle becomes inserts the loss variation.Therefore, if drift, then photoswitch is actually disabled.
In the present embodiment, according to two kinds of measures, antistatic structure is formed on the part relevant with the driving of catoptron 8103 (near the structure catoptron 8103, drive electrode 8003-1 to 8003-4 and the drive electrode 8003-1 to 8003-4).
As mentioned above, upper substrate 151, gimbals 152, catoptron 153 and torsion spring 154 and 155 are made by the monocrystalline silicon of SOI substrate integratedly.By upper substrate 151, torsion spring 154, gimbals 152 and torsion spring 155, apply earth potential to catoptron 153.Yet the actual potential of catoptron 153 is electromotive forces of Fig. 3 mid point A, and before formed capacitor C 1 between catoptron 153 and the drive electrode 103-1 to 103-4 was finished charging, the electromotive force of this A is electromotive force above Ground.This is because there is stake resistance R1 in catoptron 153 (silicon layer) shown in Figure 3.
For preventing drift, need guarantee reliably to be electrically connected, fix so that face the electromotive force of catoptron 153 lower surfaces of drive electrode 103-1 to 103-4.Yet, generally be not easy to realize this point.By insulation course, make as the silicon layer of catoptron 153 and the silicon base layer of SOI substrate electrically to disconnect.Be to obtain the beam reflection function, with the layer metal deposition of for example Au layer on the upper surface of catoptron 153.Yet, can not expect that the metal level that is deposited is electrically connected to the silicon layer of catoptron 153 silicon base layer of SOI substrate usually.Usually, on silicon face, form nature (native) oxide film with insulating property, i.e. silicon oxide layer.Therefore, even the metal level that is deposited on the upper surface of the silicon layer that is used as catoptron 153 is electrically connected to a certain electromotive force, always the silicon layer of catoptron 153 itself also not necessarily is connected to this electromotive force.
Fix for making in the face of the electromotive force of catoptron 153 lower surfaces of drive electrode 103-1 to 103-4, effectively way is, guarantees directly from electrically contacting in the face of that side of drive electrode 103-1 to 103-4 and the lower surface of catoptron 153.
In the present embodiment, as illustrated in fig. 1 and 2, the metal level 156 made and be used as antistatic structure by for example Au is formed on the lower surface of upper substrate 151, gimbals 152, catoptron 153 and torsion spring 154 and 155.Apply second electromotive force to metal level 156.This structure has reduced the stake resistance R1 among Fig. 3.
In the present embodiment, apply second electromotive force by infrabasal plate 101 and pillar 104 to metal level 156.For obtaining this electrical connection, in the present embodiment, the lip-deep insulation course 102 of each pillar 104 is partly removed, to form contact hole 106.To be formed on the contact hole 106 by the metal level 105 that for example Au makes.Metal level 105 is connected to the metal level 156 of upper substrate 151 those sides.Therefore, guarantee easily and being electrically connected of the metal level 156 that is difficult to interconnect.
On catoptron 153 lower surfaces that are formed on as the metal level 156 of antistatic structure in the face of drive electrode 103-1 to 103-4, and apply second electromotive force, determine the electromotive force of catoptron 153 lower surfaces thus to metal level 156.This allows the drift of inhibitory reflex mirror 153.
[second embodiment]
Next will be described with reference to Figure 4 second embodiment of the invention.With the same section in the Reference numeral presentation graphs 4 identical among Fig. 1 and 2.In the first embodiment, by infrabasal plate 101 and the pillar of making by monocrystalline silicon 104, apply second electromotive force to metal level 156.Otherwise, as shown in Figure 4, can apply second electromotive force to metal level 156 by formed metal mainstay 107 on the insulation course 102.For forming pillar 107, for example by electroplating the metal that deposits as Au.In second embodiment, because might under the situation of nonintervention silicon layer, guarantee and being electrically connected of metal level 156, so can suitably set the electromotive force of catoptron 153 lower surfaces.
[the 3rd embodiment]
Next will be described with reference to Figure 5 third embodiment of the invention.With the same section in the Reference numeral presentation graphs 5 identical among Fig. 1 and 2.In the first embodiment, by infrabasal plate 101 and the pillar of making by monocrystalline silicon 104, apply second electromotive force to metal level 156.Otherwise, as shown in Figure 5, the insulation course on the infrabasal plate 101 102 partly can be removed, to form contact hole 109.The pillar of making by for example Au 108 can be formed, so that apply second electromotive force to metal level 156 by pillar 108 on contact hole 109.This has made things convenient for the electrical connection to pillar 108.
In first to the 3rd embodiment,, for example can remove metal level 105 or 156 or the lip-deep oxide film of pillar 107 and 108 by acid for obtaining to be electrically connected with the reliable of metal level 156.Mechanical Contact not only, and, can guarantee being electrically connected between the metal level 105 and 106, or being electrically connected between metal level 156 and pillar 107 or 108 as the scolder of AuSn alloy or as the electroconductive binder of elargol.
[the 4th embodiment]
Below with reference to Fig. 6 four embodiment of the invention is described.With the same section in the Reference numeral presentation graphs 6 identical among Fig. 1 and 2.In the present embodiment, there is antistatic structure in infrabasal plate 101 those sides.Because normally apply first electromotive force to drive electrode 103-1 to 103-4, so the electromotive force of drive electrode 103-1 to 103-4 is uncertain anything but by metal wiring.Therefore, can avoid the voltage of drive electrode 103-1 to 103-4 not follow the problem of the voltage that puts on distribution.
Can be divided into several sections to electric spurious portion with uncertain electromotive force.The example of these parts is infrabasal plates 101.Normally, the area of catoptron 153 is greater than the area of relative drive electrode 103-1 to 103-4.Therefore, infrabasal plate itself may reside in the position in the face of catoptron 153.If the electromotive force of infrabasal plate 101 is different from the electromotive force of catoptron 153, then with in the face of the corresponding electrostatic forcing of existing electric charge in the infrabasal plate 101 of catoptron 153 in catoptron 153.These electric charges are shifted to the first electromotive force side gradually by the resistance R among Fig. 34, perhaps shift to the second electromotive force side gradually by resistance R 3.Therefore, catoptron 153 has drifted about.
For preventing catoptron 153, importantly infrabasal plate 101 is made as second electromotive force identical with catoptron 153 owing to infrabasal plate 101 drifts about.In the present embodiment, form antistatic structure in the following manner.Infrabasal plate 101 uses conductive material (being monocrystalline silicon in the present embodiment).Remove below the infrabasal plate 101 or the oxide film of side.There is not the part depositing metal layers 110 of oxide film.Apply second electromotive force by metal level 110 to infrabasal plate 101.This structure has reduced the stake resistance R3 among Fig. 3.
As mentioned above, in the present embodiment, infrabasal plate 101 uses conductive material.Remove below the infrabasal plate 101 or the oxide film of side.There is not the part depositing metal layers 110 of oxide film.Apply second electromotive force by metal level 110 to infrabasal plate 101.Therefore, infrabasal plate 101 might be defined as the electromotive force identical with catoptron 153, and the drift of inhibitory reflex mirror 153.
[the 5th embodiment]
Next will be described with reference to Figure 7 fifth embodiment of the invention.With the same section in the Reference numeral presentation graphs 7 identical among Fig. 1 and 2.
The 4th embodiment has been guaranteed the reliable electrical connection of infrabasal plate 101.Next problem is to be present in the lip-deep insulation course of drive electrode 103-1 to 103-4.Generally, on each the surface of drive electrode 103-1 to 103-4, form insulation course, with guard electrode and prevent short circuit, though in Fig. 1,2,4,5,107 and 108 not shown this point.In case apply first electromotive force to drive electrode 103-1 to 103-4, this insulation course is polarization just.Even this insulation course also has limited conductance, though this conductance is very little.Therefore, electric charge moves by the preset time constant, and finally makes this insulation course and drive electrode 103-1 to 103-4 equipotential.
At last, the distance between drive electrode 103-1 to 103-4 and the catoptron 153 has reduced and the corresponding amount of the thickness of this insulation course.The power that attracts each other between drive electrode 103-1 to 103-4 and the catoptron 153 reduces and increases with distance between them.Therefore, catoptron 153 has drifted about.Polarized discharge time constant in the insulation course is bigger usually, and changes in the scope from a few minutes by several hours.
As shown in Figure 7, in the present embodiment, the lip-deep insulation course 111 of each of drive electrode 103-1 to 103-4 all has opening 112, and this opening 112 is as above-mentioned antistatic structure.The removal (short circuit) of capacitor C 1 and resistance R 2 in this presentation graphs 3.
As mentioned above, in the present embodiment, the lip-deep insulation course 111 of each of drive electrode 103-1 to 103-4 all has opening 112.Therefore, might have the part of big charge constant from eliminating near the drive electrode 103-1 to 103-4, and prevent the drift of catoptron 153.
[the 6th embodiment]
Next will sixth embodiment of the invention be described with reference to figure 8 and 9.With the same section in the Reference numeral presentation graphs 8 and 9 identical among Fig. 1 and 2.
With reference to figure 8 and 9, distribution 113-1 to 113-4 applies first electromotive force to drive electrode 103-1 to 103-4 respectively.Metal level 114 is formed on around the drive electrode 103-1 to 103-4.
The 5th embodiment allows to avoid the polarization/discharge in the insulation course on the drive electrode 103-1 to 103-4.Next problem is infrabasal plate 101 lip-deep insulation courses 102.With the same in the 5th embodiment, remove the insulation course on the drive electrode 103-1 to 103-4 easily.Yet, usually can not remove insulation course 102, because drive electrode 103-1 to 103-4 and distribution are formed on the insulation course 102.
In the present embodiment, around the drive electrode 103-1 to 103-4 that is formed on as the metal level 114 of antistatic structure on the insulation course 102.As catoptron 153, apply second electromotive force to metal level 114.As mentioned above, the area of catoptron 153 is greater than the area of drive electrode 103-1 to 103-4.Therefore, the insulation course around the drive electrode 103-1 to 103-4 102 is in the face of the periphery of catoptron 153.Metal level 114 is formed on the insulation course 102 in the face of catoptron 153.Can form metal level 114 simultaneously with drive electrode 103-1 to 103-4 and distribution 113-1 to 113-4.
For applying second electromotive force, need provide the distribution that is connected to metal level 114 to a plurality of metal levels 114.Yet this is infeasible, because the quantity of distribution has increased, and distribution must be crossed over distribution 113-1 to 113-4 arrival drive electrode 103-1 to 103-4.As shown in Figure 9, the insulation course on the infrabasal plate 101 102 is partly removed, to form contact hole 115.When on contact hole 115, forming metal level 114, metal level 114 and infrabasal plate 101 equipotentials.This structure has made things convenient for the electrical connection to metal level 114 under situation about distribution not being guided on the top layer.
As mentioned above, in the present embodiment, around the drive electrode 103-1 to 103-4 that is formed on as the metal level 114 of antistatic structure on the insulation course 102, and apply second electrode to metal level 114.Might have the part of big charge constant from eliminating near the drive electrode 103-1 to 103-4, and prevent the drift of catoptron 153.
[the 7th embodiment]
Next be described with reference to Figure 10 seventh embodiment of the invention.Represent same section among Figure 10 with Reference numeral identical among Fig. 1 and 2.
In the 6th embodiment, distribution 113-1 to 113-4 is formed on the plane identical with drive electrode 103-1 to 103-4.As shown in figure 10, can be formed on distribution 113-1 to 113-4 and drive electrode 103-1 to 103-4 on the Different Plane.In the present embodiment, distribution 113-1 to 113-4 is formed on the insulation course 102.Insulation course 115 is deposited on insulation course 102 and the distribution 113-1 to 113-4.Drive electrode 103-1 to 103-4 and metal level 114 are formed on the insulation course 115.With distribution 113-1 to 113-4 together, simultaneously the distribution 116 that is connected to metal level 114 is formed on the insulation course 102.Metal level 114 receives the electromotive force identical with catoptron 153, or has second electromotive force of skew by distribution 116 receptions.This structure has made things convenient for the electrical connection to metal level 114 under situation about distribution not being guided on the top layer.
In the present embodiment, also can side by side distribution 117 be formed on the insulation course 102 with distribution 113-1 to 113-4.Can be formed on insulation course 115 to the metal mainstay 118 that is used to support upper substrate 151, an end of each distribution 117 all is exposed to insulation course 115.At this moment, make drive electrode 103-1 to 103-4 and pillar 118 separate a certain distance (for example about several microns to 25 μ m), so that do not cause to metal level 114 and pillar 118 discharges.For forming pillar 118, for example by electroplating plated metal such as Au.This structure allows to apply second electromotive force by pillar 118 and distribution 117 to metal level 156, and guarantees the electromotive force setting on catoptron 153 lower surfaces.
In the present embodiment, with the same in first embodiment, metal level 156 can pass through infrabasal plate 101 and pillar 104, rather than utilizes pillar 118, receives second electromotive force.In this case, as shown in Figure 2, the lip-deep insulation course 102 of each pillar 104 is partly removed, to form contact hole 106.To be formed on the contact hole 106 by the metal level 105 that for example Au makes.Metal level 105 is connected to the metal level 156 of upper substrate 151 those sides.This structure also allows to apply second electromotive force to metal level 156, and guarantees the electromotive force setting on catoptron 153 lower surfaces.
As mentioned above, in the present embodiment, around the drive electrode 103-1 to 103-4 that is formed on as the metal level 114 of antistatic structure on the insulation course 102, and apply second electromotive force to metal level 114 by distribution 116.Might have the part of big charge constant from eliminating near the drive electrode 103-1 to 103-4, and prevent the drift of catoptron 153.
With reference to Figure 10, the distribution 116 that is connected to metal level 114 is separated to be provided with the distribution 117 that is connected to pillar 118.Yet these distributions can interconnect.
In first to the 7th embodiment, first electromotive force 〉=second electromotive force.Yet, the invention is not restricted to this, but first electromotive force≤second electromotive force can be set up also.
[the 8th embodiment]
Next eighth embodiment of the invention will be described.
Figure 11 and 12 shows the example of traditional reflective lens array.Show to Figure 11 and 12 major parts the mirror device of catoptron as the reflection mirror array component units.Reflection mirror array comprises a plurality of mirror devices with the matrix form two-dimensional arrangement.
Comprise torsion spring in a zigzag and be set in the notch of removable framework 8220 this removable framework connecting portion 8211a and 8211b are connected to removable framework 8220 with frame section 8210.Comprise torsion spring in a zigzag and be set in the notch of removable framework 8220 this catoptron connecting portion 8221a and 8221b are connected to catoptron 8230 with removable framework 8220.
Four sector electrode 8340a to 8340d are formed on base portion 8310 upper surfaces that comprise teat 8320 outside surfaces.Around electrode 8340a to 8340d, recess 8350a to 8350d is formed in the face of the removable framework connecting portion 8211a of the mirror substrate 8201 of opposition and the position of 8211b and catoptron connecting portion 8221a and 8221b, when when upside is watched, these recesses 8350a to 8350d has the almost shape of rectangle.A pair of protuberance 8360a and 8360b are formed on the upper surface of base portion 8310, so that first to the 3rd step 8321 to 8323 and recess 8350a to 8350d are clipped in the middle.On the upper surface of base portion 8310, distribution 8370 is formed between recess 8350a and the protuberance 8360a, and between recess 8350c and the protuberance 8360b.Electrode 8340a to 8340d is connected to distribution 8370 by lead-in wire 8341a to 8341d.
By with the lower surface engages of frame section 8210 to the upper surface of protuberance 8360a and 8360b, so that catoptron 8230 is faced the electrode 8340a to 8340d corresponding with it, and makes above-mentioned mirror substrate 8201 and electrode base board 8301 form mirror device 8200 shown in Figure 12.By the following method that will describe, make the reflection mirror array that has with a plurality of mirror devices 8200 of matrix arrangement.
At first, make that side of SOI substrate with buried insulating layer 8241 (first type surface: soi layer) stand known photoetching and as the etching of DEEP RIE, so that in monocrystalline silicon layer, form the groove of the shape that meets frame section 8210, removable framework connecting portion 8211a and 8211b, removable framework 8220, catoptron connecting portion 8221a and 8221b and catoptron 8230.
On the lower surface of SOI substrate, be formed on the resist pattern that has opening in the presumptive area corresponding with these grooves.The etchant of utilization such as potassium hydroxide optionally etches away silicon from the lower surface of SOI substrate.In this etching,, come on the lower surface of SOI substrate, to form opening and shaped as frame parts 8240 by buried insulating layer 8241 is used as etching stopping layer.
By utilizing hydrofluorite to carry out wet etching or utilizing CF base gas to carry out dry ecthing, remove buried insulating layer 8241 zones that are exposed to this opening.
Utilize this technology, form mirror substrate 8201 with above-mentioned shape.
On the other hand, form electrode base board 8301 by for example silicon substrate.
At first, by the predetermined mask pattern of being made by silicon nitride film or silicon oxide film being used as mask and use, come optionally etching silicon substrate as the alkaline solution of potassium hydroxide solution.By repeating above-mentioned technology, form base portion 8310, first to the 3rd step 8321 to 8323, pivot 8330, recess 8350 and protuberance 8360a and 8360b.
Make the silicon substrate surface oxidation of etched side, to form silicon oxide film.
For example on silicon oxide film, form metal film, and come this metal film is carried out patterning, to form electrode 8340a to 8340d, lead-in wire 8341a to 8341d and distribution 8370 by known photoetching and etching by gas deposition.
Utilize this technology, form electrode base board 8301 with above-mentioned shape.
Then, mirror substrate 8201 is joined on the electrode base board 8301, have the reflection mirror array of mirror device 8200 with formation, this mirror device 8200 can come mobile mirror 8230 by applying electric field to electrode 8340a to 8340d.In order to improve the reflectivity of catoptron 8230, can on the upper surface of catoptron 8230, form metal film, as golden film.
In the mirror device 8200 of reflection mirror array, provide attractive force by applying the electric field that individual voltage produces to electrode 8340a to 8340d to catoptron 8230, and made catoptron 8230 rotate the angle in several years via distribution 8370.The rotating operation of catoptron 8230 is described below with reference to Figure 13.For convenience of description, the vertical direction of the Figure 13 that sees from the front will be called as height or depth direction.The top of Figure 13 will be called as upside, and the bottom of Figure 13 will be called as downside.
As the characteristic feature of light MEMS type mirror device, a certain angle by the unique decision of electrode structure of electrode base board can be stablized, be turned to statically to catoptron.As shown in figure 13, catoptron 8230 draws in angle of rotation θ
pAnd close like providing on the teat 8320 between the tiltangle of formed electrode 8340a to 8340d by following formula
θ
p＝(1/3)θ …(1)
For catoptron 8230 is mainly rotated under low-voltage as much as possible, electrode 8340a to 8340d must be arranged in the face of catoptron 8230, so that they can have and catoptron 8230 area identical, and have formed the pitch angle of the teat 8320 of electrode 8340a to 8340d above also must increasing.For example, this can realize by the difference of elevation that increases teat 8320.
Yet, be difficult to increase the difference of elevation of teat 8320 by convention, because distribution 8370 is formed on the surface identical with the bottom surface of teat 8320.
As mentioned above, by be coated in photoresist on the metal film, utilize exposure sources with the pattern transfer of distribution 8370 to photoresist and carry out etching, come on electrode base board 8301, to form distribution 8370.The exposure sources accurately degree of depth of pattern transferring (depth of field) is limited (maximum 50 to 70 μ m).If expose beyond this restriction, the pattern that then will be transferred on the photoresist will defocus, thereby be difficult to form meticulous Wiring pattern.Especially, because distribution 8370 comprises many distributions, so require precision to form Wiring pattern with several microns.
By convention, shown in Figure 11 to 13, at base portion 8310, be on the bottom of the 3rd step 8323 of teat 8320, form distribution 8370.The difference of elevation of teat 8320 exposes because be made as distribution 8370, so must be limited to 50 to 70 μ m by focusing lower limit with exposure sources.Yet in order to increase the angle of rotation of catoptron 8230, the difference of elevation of teat 8320 must be greater than above-mentioned restriction, and is preferably 100 μ m or bigger.For realizing this difference of elevation, must use special-purpose exposure sources with big focusing range, perhaps each elevation is repeatedly carried out exposure, cause cost to increase thus.
For addressing the above problem present embodiment has been proposed, the purpose of present embodiment provides a kind of low voltage drive and cost can realized and reduces and can increase the mirror device of catoptron angle of rotation, a kind of reflection mirror array, and a kind of mirror device manufacture method.
Next will present embodiment be described with reference to figs. 14 to 16B.Show to Figure 14 to 16B major part the mirror device of catoptron as the reflection mirror array component units.Comprise a plurality of mirror devices according to the reflection mirror array of present embodiment with the matrix form two-dimensional arrangement.
Mirror device according to present embodiment has following structure: have the mirror substrate 200 of catoptron and have the electrode base board 300 parallel layouts of electrode.
Comprise torsion spring in a zigzag and be set in the notch of removable framework 220 this removable framework connecting portion 211a and 211b are connected to removable framework 220 with frame section 210.This structure can be rotated removable framework 220 around passing through this turning axle to removable framework connecting portion 211a and 211b (removable framework turning axle).
Comprise torsion spring in a zigzag and be set in the notch of removable framework 220 this catoptron connecting portion 221a and 221b are connected to catoptron 230 with removable framework 220.This structure can be rotated catoptron 230 around passing through this turning axle to catoptron connecting portion 221a and 221b (catoptron turning axle).
Removable framework turning axle and catoptron turning axle are with right angle intersection.
Four sector electrode 360a to 360d are formed on the upper surface of the outside surface of teat 340 and outer fissure 330, and are concentric and have and catoptron 230 circles of the same area with catoptron 230 to form.A pair of protuberance 370a and 370b are formed on the upper surface 320a of base portion 320, so that outer fissure 330 is clipped in the middle.On the upper surface 320a of base portion 320, distribution 380 is formed between protuberance 370a and 370b and the outer fissure 330.Distribution 380 is connected to electrode 360a to 360d by lead-in wire 361a to 361d.
As shown in figure 14, the lower surface of second step 342 is the upper surface of the 3rd step 343 and the upper surface flush of base portion 320.
Form the reflection mirror array that has with a plurality of mirror devices of matrix form two-dimensional arrangement in the following manner: mirror substrate 200 is joined on the electrode base board 300 with said structure, more particularly, be on the lower surface of upper surface with the protuberance 370a of electrode base board 300 and the 370b frame section 210 that joins mirror substrate 200 to, so that the catoptron 230 of mirror substrate 200 is in the face of the electrode 360a to 360d corresponding with catoptron 230.
Next will a kind of method of making electrode base board 300 be described referring to figs. 17A through 20F.
At first,, make silicon substrate 400 oxidations, so that on the surface of silicon substrate 400, form by SiO in order on silicon substrate 300, to form pivot 350
2The dielectric film of making 401 is shown in Figure 17 A.
Shown in Figure 17 B, photo anti-corrosion agent material is coated on the upper surface of dielectric film 401, to form diaphragm 402.
Shown in Figure 17 C, by known photoetching diaphragm 402 is carried out patterning, to form mask pattern (pivot is pre-formed mask pattern) 403.
Shown in Figure 17 D, come etching dielectric film 401 by pivot being pre-formed mask pattern 403 as mask, so that in dielectric film 401, form mask pattern (pivot formation mask) 404.For example, can carry out this etching by known wet etching or dry ecthing.
Shown in Figure 18 A, for example remove pivot and be pre-formed mask pattern 403 by ashing.
Shown in Figure 18 B, by pivot is formed mask pattern 404 as mask, come etching silicon substrate 400, to form pivot 350.By utilizing alkaline solution to carry out wet etching, carry out this etching as potassium hydroxide solution.
Shown in Figure 18 C, come to remove pivot by for example hydrofluorite and form mask pattern 404 from the upper surface of silicon substrate 400.Thereby, on the surface of silicon substrate 400, formed pivot 350.
Shown in Figure 19 A,, on the surface of silicon substrate 400, form first step 341 according to the program identical with Figure 17 A to 18C.
Shown in Figure 19 B, the program according to identical with forming first step 341 forms second step 342 on the surface of silicon substrate 400.
Shown in Figure 19 C, the program according to identical with forming second step 342 forms outer fissure 330, the 3rd step 343 and protuberance 370a and 370b on the surface of silicon substrate 400.Thereby, formed the shape of base portion 320.
Then, shown in Figure 20 A, make base portion 320 oxidations, so that on base portion 320 surfaces that comprise teat 340, form dielectric film 321.
Shown in Figure 20 B,, on base portion 320 surfaces, form the metal film of making by for example aluminium (metal film that is used for electrode/distribution) 405 with dielectric film 321 for example by sputter or gas deposition.
Shown in Figure 20 C, on the surface of metal film 405, form the diaphragm of making by photo anti-corrosion agent material 406.
Shown in Figure 20 D, by known photoetching diaphragm 406 is carried out patterning, so that form the pattern 407 of Wiring pattern with the electrode 360a to 360d shown in Figure 14,16A and the 16B, lead-in wire 361a to 361d and distribution 380.
The upper surface 320a that is used for the focus that Wiring pattern is transferred to the exposure sources on the diaphragm 406 is located at base portion 320, distribution 380 will be formed on the upper surface 320a of base portion 320.This permission forms distribution 380 with highest resolution.
On the other hand, electrode 360a to 360d and lead-in wire 361a to 361d are gone up the upper surface 320a at base portion 320 between the formed first step 341 and outer fissure 330 in short transverse (from front 16A with the aid of pictures time vertical direction), promptly from the top of the upper surface 320a of base portion 320 to the bottom, be the center almost simultaneously with upper surface 320a.Therefore, when under exposure sources is focusing on the situation of upper surface 320a of base portion 320, carrying out exposure, even accurately in the scope of pattern transferring or electrode 360a to 360d and lead-in wire 361a to 361d near the zone, that have less image defocus, also finished pattern transfer for exposure sources.Therefore, might accurately form electrode 360a to 360d and lead-in wire 361a to 361d.
Shown in Figure 20 E,, comprise the wiring layer 408 of the electrode 360a to 360d shown in Figure 14 to 16B, lead-in wire 361a to 361d and distribution 380 with formation by pattern 407 is come etching metal film 405 as mask.
Shown in Figure 20 F, for example remove pattern 407 by ashing.
Reflection mirror array according to electrode base board 300 present embodiment, that have such manufacturing can be by applying predetermined bias via distribution 380 to all electrode 360a to 360d, and apply independent displacement voltage to electrode 360a to 360d, catoptron 230 is rotated.
According to present embodiment, even when using traditional exposure sources, the difference of elevation of teat 340 also can obtain the expectation value of for example about 100 μ m.Therefore, teat 340 can obtain big pitch angle, makes catoptron 230 can obtain than big in the past angle of rotation.In addition, electrode 360a to 360d has the size identical with catoptron 230, therefore can drive catoptron 230 with low-voltage.
Outer fissure not necessarily needs to have above-mentioned single step arrangement, but can have multilevel hierarchy.Figure 21 shows a kind of reflection mirror array with outer fissure of multilevel hierarchy.Represent same composition element among Figure 21 with title identical in the mirror device shown in Figure 14 to 16B or Reference numeral, and will omit description of them as required.Figure 21 is the cross-sectional view that the part identical with Figure 16 A, 16B is shown.
First outer fissure 331 comprises the recess that is formed in the base portion 320.This recess has the block Pyramid of upper surface greater than the bottom surface.The upper surface of first outer fissure 331 and the upper surface flush of second step.
Second outer fissure 332 comprises the recess in the bottom surface that is formed on first outer fissure 331.This recess has the block Pyramid of upper surface greater than the bottom surface.Teat 340 is formed on the bottom surface of second outer fissure 332.Electrode 360a to 360d is formed on second outer fissure 332 and the teat 340.
As shown in figure 21, the lower surface of first step 341 is the flush of the upper surface and the base portion 320 of second step 342.The lower surface of second step 342 is the upper surface of the 3rd step and the upper surface flush of first outer fissure 331.
Even in Figure 21, in the process of photoresist, exposure sources also is located at focus on the upper surface of base portion 320 in a pattern transfer that is used as electrode 360a to 360d, lead-in wire 361a to 361d and distribution 380.Therefore, can form distribution 380 with several microns precision.Even for electrode 360a to 360d and lead-in wire 361a to 361d, also exposure sources accurately in the scope of pattern transferring or near, in the zone with less image defocus, finish pattern transfer.Therefore, might accurately form electrode 360a to 360d and lead-in wire 361a to 361d.
As a result, the difference of elevation of teat 340 can obtain the expectation value of for example about 100 μ m.Therefore, teat 340 can obtain big pitch angle, makes catoptron 230 can obtain than big in the past angle of rotation.
Especially, in electrode base board shown in Figure 21, can be less than this difference of elevation the electrode base board shown in Figure 16 A and the 16B from the upper surface 320a of base portion 320 to the difference of elevation of pivot 350.Therefore, utilize exposure sources to carry out in the process of pattern transfer when forming pivot 350, the upper surface 320a of base portion 320 defocusing in vertical direction can be littler.Therefore, might form pattern more accurately.
Can by with make the identical method of reflection mirror array shown in above-mentioned Figure 14 to 16B, make the reflection mirror array of outer fissure with multilevel hierarchy shown in Figure 21.
Outer fissure not necessarily needs to have above-mentioned one-piece construction, but can have isolating construction.Figure 22 shows a kind of reflection mirror array with outer fissure of isolating construction.Figure 22 is the cross-sectional view that illustrates according to the modification of the electrode base board of the reflection mirror array of present embodiment.Represent same composition element among Figure 22 with title identical in the mirror device shown in Figure 14 to 16B and Reference numeral, and will omit description of them as required.
Each of outer fissure 333a to 333d all comprises the recess that is formed in the base portion 320.This recess has the block Pyramid of upper surface greater than the bottom surface.Outer fissure 333a to 333d is formed by point symmetry ground, to surround teat 340, and to form and teat 340 and the concentric rectangle of electrode 360a to 360d.
Can form teat 340 like this, so that its difference of elevation obtains expectation value.For example, when teat 340 comprises correspondingly with the 3rd step when almost blocking the pyramid part, teat 340 can obtain the difference of elevation of for example about 100 μ m.Therefore, teat 340 can obtain big pitch angle, makes catoptron 230 can obtain than big in the past angle of rotation.
Each of lead-in wire 361a to 361d all is formed between adjacent two outer fissures of the outer fissure 333a to 333d on the base portion 320.Therefore, lead-in wire 361a to 361d and distribution 380 are formed on the base portion 320.
Even in Figure 22, in the process of photoresist, exposure sources also is located at focus on the upper surface of base portion 320 in a pattern transfer that is used as electrode 360a to 360d, lead-in wire 361a to 361d and distribution 380.Therefore, can form distribution 380 with several microns precision.Especially in Figure 22, because lead-in wire 361a to 361d is formed on the base portion 320, thus distribution 380 not only, and go between 361 to 361d, can both form with several microns precision.Even for electrode 360a to 360d, also exposure sources accurately in the scope of pattern transferring or near the zone with less image defocus in, finish pattern transfer.Therefore, might accurately form electrode 360a to 360d.
As a result, the difference of elevation of teat 340 can obtain expectation value.Therefore, teat 340 can obtain big pitch angle, makes catoptron 230 can obtain than big in the past angle of rotation.
Can by with make the identical method of reflection mirror array shown in above-mentioned Figure 14 to 16B, make reflection mirror array with separation outer fissure shown in Figure 22.
In the present embodiment, by etching silicon substrate 400, form electrode base board 300,301 or 302 with teat 340 grades.Otherwise, can form electrode base board 300,301 or 302 by depositing any substrate on the substrate arbitrarily with teat 340 grades.
As mentioned above, according to present embodiment, because teat is formed in the base portion in the formed ditch, to increase the difference of elevation of teat, so catoptron can obtain big angle of rotation.Distribution is formed on the base portion, and electrode is formed on formed ditch in the substrate and the teat that from ditch, stretches out on.Therefore, the focus of exposure sources is located on the upper surface of base portion, allows to form distribution and electrode with required precision.
[the 9th embodiment]
At first the conventional mirror device will be described.As shown in figure 13, in conventional mirror device 8200, provide attractive force by applying the electric field that individual voltage produces to electrode 8340a to 8340d to catoptron 8230, and make catoptron 8230 rotate the angle in several years via distribution 8370.When not having voltage to put on electrode 8340a to 8340d, catoptron 8230 almost is parallel to electrode base board 8301 (this will be called as initial position below state), shown in the solid line among Figure 13.When the electrode 8340a to 8340d under this state applies individual voltage, catoptron 8230 will tilt, shown in the dotted line among Figure 13.
Figure 23 shows the photoswitch with mirror device 8200.Photoswitch 8400 comprises: pair of alignment instrument array 8410 and 8420, and each collimator array all has many optical fiber of two-dimensional arrangement; And a pair of reflection mirror array 8430 and 8440, each reflection mirror array all has a plurality of above-mentioned mirror device 8200 of two-dimensional arrangement.In photoswitch 8400, from the light beam as collimator array 8410 input of input port be reflected mirror 8430 and 8440 reflections, arrive collimator array 8420 as output port, and from 8420 outputs of collimator array.For example, enter the mirror device 8200a of the light beam a irradiation reflection mirror array 8430 of photoswitch 8400 from the optical fiber 8410a of collimator array 8410.This light beam a catoptron 8230 reflection of mirror device 8200a that is reflected, and arrive the mirror device 8200b of reflection mirror array 8440.With the same in the reflection mirror array 8430, in reflection mirror array 8440, this light beam a catoptron 8230 reflection of mirror device 8200b that is reflected, and arrive the optical fiber 8420a of collimator array 8420.Like this, photoswitch 8400 can be the collimated light from collimator array 8410 input, spatially is cross connected to collimator array 8420 with the form of light beam, and need not converts thereof into electric signal.
In photoswitch 8400, the same composition element of the mirror device 8200 of two-dimensional arrangement in reflection mirror array 8430 and 8440 is of similar shape.For example, between catoptron, the size of catoptron 8230, the shape of removable framework connecting portion 8211a and 8211b and catoptron connecting portion 8221a and 8221b, between catoptron 8230 and removable framework connecting portion 8211a and the 8211b or the relative position between catoptron 8230 and catoptron connecting portion 8221a and the 8221b, relative position between catoptron 8230 and the electrode 8340a to 8340d, and the size of electrode 8340a to 8340d are all constant.As mentioned above, in traditional photoswitch 8400, have identical shaped mirror device 8200 and be arranged in reflection mirror array 8430 and 8440.Therefore, each catoptron 8230 in the reflection mirror array 8430 and 8440 all almost is parallel to electrode base board 8301, as shown in figure 24.Figure 24 illustrates the cross section of the catoptron 8230 that is arranged in a plurality of mirror devices 8200 in reflection mirror array 8430 and 8440.Reflection mirror array 8430 has the catoptron 8431 to 8435 corresponding with catoptron 8230.Reflection mirror array 8440 has the catoptron 8441 to 8445 corresponding with catoptron 8230.
At initial position, the catoptron 8431 to 8435 of reflection mirror array 8430 almost is parallel to electrode base board 8301, and arranges like this, so that the corresponding catoptron in the reflection mirror array 8440 of light beam irradiates opposition.For example, catoptron 8431 is with (the following light beam that will be called a) reflexes to catoptron 8441 as catoptron 8431 homologues by the indicated light beam of a among Figure 24.Catoptron 8433 will reflex to the catoptron 8443 as catoptron 8433 homologues by the indicated light beam of b (following will be called light beam b) among Figure 24.Catoptron 8435 utilizes among Figure 24 by the indicated light beam of c (following will be called light beam c) and shines the catoptron 8445 as catoptron 8435 homologues.The catoptron of opposition represents, for example when from reflection mirror array of back projection of beam reflection face and when the beam reflection face is watched another reflection mirror array, is arranged in the catoptron of the reflection mirror array same position of opposition.
When the electrode 8340a to 8340d of the catoptron in the reflection mirror array 8430 of photoswitch 8,400 8431 to 8435 applies individual voltage so that catoptron 8431 to 8435 when tilting, the light beam of irradiation catoptron 8431 to 8435 can shine any catoptron in the reflection mirror array 8440.
Yet in the traditional reflective lens array, if should make the light beam irradiates two dimension target by the mirror tilt that makes mirror device, the mirror tilt angle will become with the position of the mirror device in the reflection mirror array.
For example, in the photoswitch 8400 with a pair of reflection mirror array 8430 and 8440 shown in Figure 24, when catoptron 8431 in positive dirction (when the front is seen, to the right direction among Figure 24) go up from 1/2 o'clock of initial position cant angle theta 1, light beam a will shine 8440 catoptron 8445 as the reflection mirror array of target.Therefore, for all catoptrons 8441 to 8445 with light beam a irradiation opposition reflection mirror array 8440, catoptron 8431 must can be from 1/2 of initial position cant angle theta 1 on positive dirction.
Go up from 1/2 o'clock of initial position cant angle theta 2 in negative direction (when the front is seen, left direction among Figure 24) when catoptron 8433, light beam b will shine catoptron 8441.When catoptron 8433 on the positive dirction from initial position cant angle theta 3 1/2 the time, light beam b will shine catoptron 8445.Therefore, for all catoptrons 8441 to 8445 with light beam b irradiation opposition reflection mirror array 8440, catoptron 8433 must be from 1/2 of initial position cant angle theta 2 on negative direction, and can be from 1/2 of initial position cant angle theta 3 on positive dirction.
When catoptron 8435 on the negative direction from initial position cant angle theta 4 1/2 the time, light beam c will shine catoptron 8441.Therefore, for all catoptrons 8441 to 8445 with light beam c irradiation opposition reflection mirror array 8440, catoptron 8435 must can be from 1/2 of initial position cant angle theta 4 on negative direction.
As mentioned above, in the traditional reflective lens array, the mirror tilt angle becomes with the position in the reflection mirror array.Yet, identical shaped because mirror device has, so for mirror device included in the same reflection mirror array, all mirror devices required equal angular that all must be able to tilt.For example, the catoptron 8431 to 8435 among Figure 24 must be at positive dirction 1/2 of the θ 1 that tilts, and can be at negative direction 1/2 of the θ 4 that tilts.Yet, because use the mirror device of MEMS technology to be difficult under low-voltage, increase the mirror tilt angle, so need a kind of mirror device that can reduce the mirror tilt angle.
Proposed present embodiment for addressing the above problem, the purpose of present embodiment provides a kind of mirror device that can reduce the mirror tilt angle, a kind of reflection mirror array and a kind of photoswitch.
Next present embodiment will be described.In the present embodiment, the position deviation of fulcrum projection the catoptron center, to reduce the mirror tilt angle.Represent same composition element in the 9th embodiment with Reference numeral identical in the 8th embodiment.Show to Figure 25 A and 25B major part the mirror device of catoptron as the component units of reflection mirror array.
As shown in figure 26, in conventional mirror device 8200, pivot 8330 is almost faced the center of catoptron 8230.Therefore, when when electrode 8340a to 8340d applies even voltage, attractive force will act on entire emission mirror 8230 uniformly.Catoptron 8230 is near electrode base board 8301 those sides, and contacts with pivot 8330.Catoptron 8230 almost is parallel to electrode base board 8301, promptly perpendicular to the axle (by the alternately length dotted line indication among Figure 26) of pivot 8330.
On the contrary, in the mirror device 2 of present embodiment, the position deviation of pivot 350 in the face of the center of the catoptron 230 of pivot 350.Therefore, when applying even voltage (following will be called bias voltage) to electrode 360a to 360d, catoptron 230 will contact with pivot 350, and from catoptron wherein perpendicular to the state (by the indication of the dotted line among Figure 27) (this will be called original state below state) of the axle (by the alternately length dotted line indication Figure 27) of pivot 350 predetermined angular that tilted.In the present embodiment, the electrode 360a to 360d under this state applies independent displacement voltage, and catoptron 230 is tilted about pivot 350.
Next reflection mirror array according to present embodiment will be described, and the photoswitch with this reflection mirror array.
As shown in figure 28, in the reflection mirror array 500 according to present embodiment, the mirror device described with reference to figure 25A, 25B and 27 2 is arranged two-dimensionally with matrix form.
As shown in figure 29, comprise according to the photoswitch 600 of present embodiment: pair of alignment instrument array 610 and 620, each collimator array all has many optical fiber of two-dimensional arrangement; And a pair of reflection mirror array 510 and 520, each reflection mirror array all comprises above-mentioned reflection mirror array 500.In photoswitch 600, from the light beam as collimator array 610 input of input port be reflected lens array 510 and 520 reflections, arrive collimator array 620 as output port, and from 620 outputs of collimator array.For example, enter the mirror device 2-1 of the light beam a irradiation reflection mirror array 510 of photoswitch 600 from the optical fiber 610a of collimator array 610.This light beam a catoptron 230 reflection of mirror device 2-1 that is reflected, and arrive the mirror device 2-2 of reflection mirror array 520.With the same in the reflection mirror array 510, in reflection mirror array 520, this light beam a catoptron 230 reflection of mirror device 2-2 that is reflected, and arrive the optical fiber 620a of collimator array 620.Like this, photoswitch 600 can be the collimated light from collimator array 610 input, spatially is cross connected to collimator array 620 with the form of light beam, and need not converts thereof into electric signal.
In reflection mirror array 500, the position of the pivot 350 of each mirror device (by the dotted circle among Figure 28 indication) all departed from catoptron 230 the center (by among Figure 28 * indication), so that under original state with beam reflection to the catoptron that is positioned at the reflection mirror array center that opposes.For example, in reflection mirror array shown in Figure 28 500, the pivot 350 of each mirror device 2 all is present in the mirror device 2a that is positioned at reflection mirror array 500 centers is connected on the straight line at catoptron 230 centers of mirror device 2.When the distance of distance mirror device 2a increases, the position of the pivot 350 of each mirror device 2 all gradually from the catoptron 230 of mirror device 2 opposite side of mind-set mirror device 2a depart from.The pivot 350 of mirror device 2a is present in the position in the face of catoptron 230 centers.Therefore, when the electrode 360a to 360d to each mirror device 2 of reflection mirror array 500 applied bias voltage, catoptron 230 contacted with pivot 350 and tilts, so that with the beam reflection the received catoptron to opposition reflection mirror array center.
Figure 30 is the schematic section of reflection mirror array 510 and 520.Figure 30 illustrates the cross section of the catoptron 230 of a plurality of mirror devices 2 of arranging in reflection mirror array 510 and 520.Each of the catoptron 511 to 515 of reflection mirror array 510 and the catoptron 521 to 525 of reflection mirror array 520 is all corresponding to above-mentioned catoptron 230.
As shown in figure 30, when the electrode 360a to 360d to each mirror device 2 of reflection mirror array 510 applied bias voltage, each of catoptron 511 to 515 all depended on position in the reflection mirror array 510 and the predetermined angular that tilts.In this original state, catoptron 511 to 515 tilts, so that being input to the beam reflection of reflection mirror array 510 to the catoptron 523 that is positioned at reflection mirror array 520 centers.For catoptron 521 to 525 with light beam irradiates reflection mirror array 520,511 to 515 need of catoptron can be in positive dirction (when the front be seen, to the right direction among Figure 30) and tilt much at one angle of negative direction (when the front is seen, left direction among Figure 30).
For example, when the catoptron among Figure 30 511 on the negative direction from original state cant angle theta 5 1/2 the time, light beam a will shine catoptron 521.When catoptron 511 on the positive dirction from original state cant angle theta 6 1/2 the time, light beam a will shine catoptron 525.Therefore, in order to shine all catoptrons 521 to 525 of opposition reflection mirror array 520 with light beam a, 511 need of catoptron can be from 1/2 of original state cant angle theta 5 on negative direction, and on positive dirction from 1/2 of original state cant angle theta 6.
When catoptron 515 on the negative direction from original state cant angle theta 7 1/2 the time, light beam c will shine catoptron 521.When catoptron 515 on the positive dirction from original state cant angle theta 8 1/2 the time, light beam c will shine catoptron 525.Therefore, in order to shine all catoptrons 521 to 525 of opposition reflection mirror array 520 with light beam, 515 need of catoptron can be from 1/2 of original state cant angle theta 7 on negative direction, and on positive dirction from 1/2 of original state cant angle theta 8.
In traditional reflective lens array 8430 shown in Figure 24, in order to shine all catoptrons 8441 to 8445 of opposition reflection mirror array 8440 with light beam a, the catoptron 8431 corresponding with the catoptron 511 of the reflection mirror array 510 of present embodiment must can be in positive dirction from 1/2 of initial position cant angle theta 1 (=θ 5+ θ 6).In addition, the catoptron 8435 corresponding with the catoptron 515 of the reflection mirror array 510 of present embodiment must can be from 1/2 of initial position cant angle theta 4 (=θ 7+ θ 8) on negative direction.Because it is identical shaped that the mirror device 8200 of traditional reflective lens array 8430 has, so catoptron 230 must be at positive dirction 1/2 of the θ 1 that tilts, and must be at negative direction 1/2 of the θ 4 that tilts.
Yet in the present embodiment, for example as mentioned above, 511 need of catoptron can be from 1/2 of original state cant angle theta 5 on negative direction, and on positive dirction from 1/2 of original state cant angle theta 6.This angle less than, and more particularly, approximate greatly the mirror device 8200 in the conventional mirror array 8430 catoptron 230 the pitch angle 1/2.As mentioned above, the reflection mirror array according to present embodiment can reduce the mirror tilt angle.Therefore, the driving voltage of mirror device and reflection mirror array can be low.
Next a kind of method of making according to the mirror device and the reflection mirror array of present embodiment will be described.Form mirror substrate 200 by the SOI substrate.
At first, make that side of SOI substrate with buried insulating layer 250 (first type surface: soi layer) stand known photoetching and as the etching of DEEP RIE, so that in monocrystalline silicon layer, form the groove of the shape that meets frame section 210, removable framework connecting portion 211a and 211b, removable framework 220, catoptron connecting portion 221a and 221b and catoptron 230.
On the lower surface of SOI substrate, be formed on the resist pattern that has opening in the presumptive area corresponding with these grooves.By utilizing for example SF
6Carry out dry ecthing, come optionally to etch away silicon from the lower surface of SOI substrate.In this etching,, come on the lower surface of SOI substrate, to form opening and shaped as frame parts 240 by buried insulating layer 250 is used as etching stopping layer.The etching of silicon can be to use for example wet etching of potassium hydroxide.
CF6 carries out dry ecthing by for example utilizing, and removes buried insulating layer 250 zones that are exposed to this opening.Utilize this technology, form mirror substrate 201.Can utilize hydrofluorite to remove buried insulating layer 250.
On the other hand, form electrode base board 8301 by for example silicon substrate.At first, by the predetermined mask pattern of being made by silicon nitride film or silicon oxide film is used as mask and uses potassium hydroxide solution, come optionally etching silicon substrate.By repeating above-mentioned technology, form base portion 310, first and second steps 321 and 322, pivot 350 and protuberance 360a and 360b.Depend on the position in the reflection mirror array 500, pivot 350 is formed on the position of departing from first step 341 centers.The pivot 350 of the mirror device 2 of reflection mirror array 500 centers is formed on the almost center of first step 341.
Make the silicon substrate surface oxidation of etched side, to form silicon oxide film.For example on silicon oxide film, form metal film, and this metal film is carried out patterning, to form electrode 360a to 360d, lead-in wire 341a to 341d and distribution 370 by known photoetching and etching by gas deposition.Utilize this technology, form electrode base board 300 with above-mentioned shape.
Then, mirror substrate 200 is joined on the electrode base board 300, have the reflection mirror array 500 of mirror device 2 with formation, this mirror device 2 can come mobile mirror 230 by applying electric field to electrode 360a to 360d.According to the position of each mirror device 2 in the reflection mirror array 500, regulate the position of pivot 350 of each mirror device 2 of the reflection mirror array 500 of such manufacturing.In case 360a to 360d applies bias voltage to electrode, each mirror device just all beam reflection to the catoptron of the center of opposition reflection mirror array 520.This allows to reduce the pitch angle of the catoptron 230 of each mirror device 2.
In the present embodiment, reflection mirror array 500 shown in Figure 28 has 5 * 5 mirror devices 2.Yet the number of set mirror device 2 is not limited to 5 * 5 in the reflection mirror array 500, but can arbitrarily be provided with as required.
Can have the structure identical according to the reflection mirror array 520 of present embodiment with reflection mirror array 510.
According to the catoptron 230 of the mirror device 2 of present embodiment not necessarily needs tilt one-dimensionally, as shown in figure 30.Catoptron 230 can tilt two-dimensionally around removable framework turning axle and catoptron turning axle.Therefore, depend on the position of mirror device 2 in the reflection mirror array 500, come the position of the pivot 350 on the first step 341 of accommodation reflex mirror device 2 two-dimensionally.
In the present embodiment, pivot 350 is set on the teat 320.Yet pivot 350 may reside on the electrode base board 300.In this case, electrode 360a to 360d is formed on the electrode base board 300.
In the present embodiment, apply bias voltage and displacement voltage to electrode 360a to 360d.Yet, can only apply displacement voltage.
In the present embodiment, on teat 340, do not form the 3rd step 343.Yet the present invention also can be applicable to have the mirror device of the 3rd step 343.Similar, though do not form outer fissure in the present embodiment, the present invention also can be applicable to have the mirror device of outer fissure.
As mentioned above, according to present embodiment because the position deviation of fulcrum projection the catoptron center, so when when electrode applies bias voltage, mirror tilt one predetermined angular.Because catoptron tilts from this heeling condition, so the pitch angle of catoptron can be little.This also allows to drive mirror device under low-voltage.
[the tenth embodiment]
Next tenth embodiment of the invention will be described.In the present embodiment, connecting portion has different structures with the opposition connecting portion, to reduce the mirror tilt angle.
Represent same composition element in the tenth embodiment with Reference numeral identical in the 8th and the 9th embodiment.Show to Figure 31 major part the mirror device 2 of catoptron as the reflection mirror array component units.Comprise a plurality of mirror devices according to the reflection mirror array of present embodiment with the matrix form two-dimensional arrangement.
Comprise torsion spring in a zigzag and be set at the first notch 222a of removable framework 220 and among the 222b this is connected to removable framework 220 to removable framework connecting portion 211a and 211b with frame section 210.This structure can be rotated removable framework 220 around passing through this removable framework turning axle to removable framework connecting portion 211a and 211b.Removable framework connecting portion 211a has different structures with 211b, and especially has different spring constants.For example in Figure 31, removable framework connecting portion 211a is thicker than removable framework connecting portion 211b.Therefore, the spring constant of removable framework connecting portion 211a is greater than the spring constant of removable framework connecting portion 211b.
Comprise torsion spring in a zigzag and be set at the second notch 223a of removable framework 220 and among the 223b this is connected to catoptron 230 to catoptron connecting portion 221a and 221b with removable framework 220.This structure can be rotated catoptron 230 around passing through this catoptron turning axle to catoptron connecting portion 221a and 221b.Catoptron connecting portion 221a has different structures with 221b, and especially has different spring constants.For example in Figure 31, catoptron connecting portion 221a is thicker than catoptron connecting portion 221b.Therefore, the spring constant of catoptron connecting portion 221a is greater than the spring constant of catoptron connecting portion 221b.Removable framework turning axle and catoptron turning axle are with right angle intersection.
The magnitude of the spring constant of removable framework connecting portion 211a and 221b and catoptron connecting portion 221a and 221b is described below with reference to Figure 32.Figure 32 is the cross-sectional view of torsion spring included among removable framework connecting portion 211a and 211b and catoptron connecting portion 221a and the 221b.Mainly represent the range direction of mirror substrate 200 and electrode base board 300, i.e. spring constant on the Z-direction according to the spring constant of the removable framework connecting portion 211a of the reflection mirror array of present embodiment and 211b and catoptron connecting portion 221a and 221b.The spring constant magnitude of Z-direction depends on following key element.
The spring constant magnitude of Z-direction depends on the directions X length l 1 of the torsion spring among Figure 32.Length l 1 is long more, and spring constant is just more little.On the contrary, length l 1 is short more, and spring constant is just big more.
The spring constant magnitude of Z-direction also depends on the Y direction length l 2 of the torsion spring among Figure 32.Length l 2 is long more, and spring constant is just more little.On the contrary, length l 2 is short more, and spring constant is just big more.
The spring constant magnitude of Z-direction also depends on the width t of the torsion spring among Figure 32.T is more little for width, and promptly torsion spring is thin more, and spring constant is just more little.On the contrary, width t is big more, and promptly torsion spring is thick more, and spring constant is just big more.
The spring constant magnitude of Z-direction also depends on the spacing p between the adjacent torsion spring unit of the torsion spring among Figure 32, the i.e. flexuose pitch of torsion spring.Spacing p is big more, and spring constant is just more little.On the contrary, spacing p is more little, and spring constant is just big more.
The spring constant magnitude of Z-direction also depends on the zigzag of the torsion spring among Figure 32 several n that turn back.N are big more for number, and promptly the torsion spring number of turning back is big more, and spring constant is just more little.On the contrary, n are more little for number, and promptly the torsion spring number of turning back is more little, and spring constant is just big more.
The spring constant magnitude of Z-direction also depends on the thickness h of the torsion spring among Figure 32.Thickness h is more little, and promptly torsion spring is thin more, and spring constant is just more little.On the contrary, thickness h is big more, and promptly torsion spring is thick more, and spring constant is just big more.
In reflection mirror array according to present embodiment, between a pair of parts, get final product between travelling frame connecting portion 211a and the 211b and between catoptron connecting portion 221a and the 221b, have one in the above-mentioned key element at least and change.This cause removable framework connecting portion 211a and 211b and catoptron connecting portion 221a and 221b each all have the spring constant that is different from corresponding connection parts.
The same with the spring constant magnitude of above-mentioned Z-direction, the spring constant of X and Y direction and the spring constant that rotates around X-axis also become with the shape of torsion spring.This will be described with reference to figure 33A to 34B.Figure 33 A to 34B shows by for example Si and makes and have the width of torsion spring of simple rectangular section girder construction and a relation between the spring constant.With reference to figure 33A and 34A, the representative of the ordinate on the right is the spring constant of torsion spring X-axis rotation around the longitudinal axis.It is the spring constant of torsion spring Z-direction that the ordinate on the left side is represented short transverse.Horizontal ordinate is represented width, i.e. torsion spring Y direction length.With reference to figure 33A and 34A, curve a represents around the spring constant of torsion spring X-axis rotation and the relation between the torsion spring width.Curve b represents the spring constant of torsion spring Z-direction and the relation between the torsion spring width.
Shown in the curve a of Figure 33 A and 34A, the width of torsion spring is more little, and is just more little around the spring constant of torsion spring X-axis rotation.The width of torsion spring is big more, and this spring constant is just big more.When a certain parameter, as the torsion spring width relevant with the torsion spring shape, during change, the spring constant of not only above-mentioned torsion spring Z-direction, and X and Y direction spring constant and around the spring constant that X-axis is rotated also all change.If the spring constant that rotates around X-axis has changed, then also will change for making mirror tilt arrive the required voltage of predetermined angular.When the spring constant of torsion spring Z-direction changes, must set a kind of torsion spring shape that does not change the spring constant of X and Y direction and center on the spring constant of torsion spring X-axis rotation.Therefore, for example, the spring constant of X and Y direction and the spring constant that rotates around the torsion spring X-axis are fixed as arbitrary value.
For example, directions X length is 180 μ m, highly is in the torsion spring of 10 μ m in Figure 33 B, is set as 1.0 * 10 around the spring constant of X-axis rotation
-8As shown in figure 33, calculating the torsion spring width from curve a is 1.8 μ m, and to calculate the Z-direction spring constant from curve b be 69.Supposing that the torsion spring directions X length among Figure 33 B becomes 210 μ m, shown in Figure 34 B, and the same with torsion spring among Figure 33, is 1.0 * 10 around the spring constant of X-axis rotation
-8Shown in Figure 34 A, calculating the torsion spring width from curve a is 1.9 μ m, and to calculate the Z-direction spring constant from curve b be 47.
As mentioned above,,, during change, the spring constant of torsion spring Z-direction can be changed, and spring constant need not be changed around the rotation of torsion spring X-axis as torsion spring width or the length relevant with the torsion spring shape when a certain parameter.
Next will be with reference to Figure 31,35 and 36, the operation according to the mirror device of the reflection mirror array of present embodiment is described.Figure 35 and 36 shows the cross section of the major part of getting along the line I-I among Figure 31, so that the relation between explanation catoptron 230 and catoptron connecting portion 221a and the 221b.Figure 35 and 36 for example understands the mirror device that comprises without any the smooth electrode of teat.Yet present embodiment also can be applicable to have the mirror device of teat.Figure 35 and 36 also for example understands the mirror device without any outer fissure.Yet present embodiment also can be applicable to have the mirror device of outer fissure.
The one dimension tilt operation of mirror device at first will be described.In conventional mirror device 8200 shown in Figure 35, catoptron connecting portion 8221a and 8221b have same structure.Therefore, the two ends of the catoptron 8230 that is supported by catoptron connecting portion 8221a and 8221b are connected to removable framework 8220 by identical suspension force.Therefore, when when electrode 8340a to 8340d applies even voltage, attractive force will act on entire emission mirror 8230 uniformly.Catoptron 8230 becomes and almost is parallel to base portion 8310, shown in the dotted line among Figure 35.
In the mirror device 2 of present embodiment shown in Figure 36, the catoptron connecting portion 221a and the 221b that are used as a pair of parts have different structure, and especially have different spring constants.Therefore, the two ends of the catoptron 230 that is supported by catoptron connecting portion 221a and 221b are connected to removable framework 220 by different suspension force.Therefore, when apply even voltage (following will be called bias voltage) to electrode 340a to 340d, so that attraction force acts is on catoptron 230 time, catoptron 230 will be with respect to base portion 310 predetermined angulars (this will be called original state below state) that tilt, shown in the dotted line among Figure 36.
Next the two-dimentional tilt operation of mirror device will be described.In mirror device shown in Figure 31 2, removable framework connecting portion 211a has the big spring constant than removable framework connecting portion 211b, and catoptron connecting portion 221a has the big spring constant than catoptron connecting portion 221b.Therefore, when when electrode 340a to 340d applies bias voltage, the removable framework 220 that is parallel to frame section 210 is oblique to base portion 310 those inclinations, has reduced the Y direction distance (this will be called " inclination of Y direction " below motion) to base portion 310 simultaneously.The catoptron 230 that is parallel to removable framework 220 is oblique to base portion 310 those inclinations, has reduced the directions X distance (this will be called " directions X inclination " below motion) to base portion 310 simultaneously.Therefore, in the mirror device 2 of present embodiment, when when electrode 340a to 340d applies the voltage with even amplitude, the catoptron 230 that is parallel to frame section 210 will be oblique to base portion 310 those inclinations, reduce among Figure 31 arrow a side simultaneously upward to the distance (this motion is following will to be called " inclination of a direction ") of base portion 310.In the present embodiment, apply independent control voltage, catoptron 230 is tilted by the electrode 340a to 340d under this state.
Figure 37 shows the example that comprises according to the reflection mirror array of the mirror device 2 of present embodiment.Figure 37 has illustrated a kind of state that applies predetermined bias to electrode 340a to 340d.Each mirror device shown in Figure 37 all is in the state of watching from the front shown in Figure 31.That is, each mirror device all has catoptron connecting portion 221a and the 221b on the horizontal direction, and removable framework connecting portion 211a and 211b on the vertical direction.
In the reflection mirror array 700 according to present embodiment, the mirror device described with reference to Figure 31 and 36 2 is arranged two-dimensionally with matrix form.Reflection mirror array 700 is corresponding to the reflection mirror array 510 and 520 of photoswitch shown in Figure 29 600.In reflection mirror array 700, removable framework connecting portion 211a in each mirror device has the spring constant different with corresponding connection parts with each of 211b and catoptron connecting portion 221a and 221b, make applying to electrode 340a to 340d under the original state of even bias voltage, catoptron 230 beam reflection to the catoptron that is positioned at opposition reflection mirror array center.At the mirror device that is arranged in reflection mirror array 700 centers, removable framework connecting portion 211a has the spring constant identical with corresponding connection parts with each of 211b and catoptron framework 221a and 221b.
For example, go up among the mirror device 2b adjacent in the direction opposite (following will be called " directions X ") with mirror device 2a with directions X, the Z-direction spring constant of catoptron connecting portion 221a is greater than the Z-direction spring constant of catoptron connecting portion 221b, so that under original state, its catoptron 230 in the inclination of directions X greater than the inclination of the catoptron among the mirror device 2a 230 in X-direction.On-directions X among the mirror device 2c adjacent with mirror device 2b, under original state its catoptron 230 in the inclination of directions X greater than the inclination of the catoptron 230 of mirror device 2b at directions X.For example, if the catoptron connecting portion 221b of mirror device 2c and 2b has identical Z-direction spring constant, then the Z-direction spring constant of the catoptron connecting portion 221a of mirror device 2c is set as the Z-direction spring constant greater than the catoptron connecting portion 221b of mirror device 2b.
With Y side in the opposite direction (following will being called " Y direction ") go up among mirror device 2d adjacent with mirror device 2a, the Z-direction spring constant of removable framework connecting portion 211a is greater than the Z-direction spring constant of removable framework connecting portion 211b, so that under original state, its catoptron 230 in the inclination of Y direction greater than the inclination of the catoptron among the mirror device 2a 230 in Y direction.On-Y direction among the mirror device 2e adjacent with mirror device 2d, under original state its catoptron 230 in the inclination of Y direction greater than the inclination of the catoptron 230 of mirror device 2d in Y direction.For example, if the removable framework connecting portion 211b of mirror device 2d and 2e has identical Z-direction spring constant, then the Z-direction spring constant of the removable framework connecting portion 211a of mirror device 2e is set as the Z-direction spring constant greater than the removable framework connecting portion 211a of mirror device 2d.
-X and-the Y direction, promptly with Figure 37 in arrow a side in the opposite direction (following will being called " a direction ") go up among mirror device 2f adjacent with mirror device 2a, the Z-direction spring constant of removable framework connecting portion 211a is greater than the Z-direction spring constant of removable framework connecting portion 211b, and the Z-direction spring constant of catoptron connecting portion 221a is greater than the Z-direction spring constant of catoptron connecting portion 221b, so that under original state, its catoptron 230 is in X and Y direction, promptly among Figure 37 the inclination of arrow a direction (following will being called " a direction ") greater than the inclination of the catoptron among the mirror device 2a 230.On-a direction among the mirror device 2g adjacent with mirror device 2f, under original state its catoptron 230 in the inclination of a direction greater than the inclination of the catoptron 230 of mirror device 2f in a direction.For example, if the removable framework connecting portion 211b of mirror device 2f and 2g and catoptron connecting portion 221b have identical Z-direction spring constant, then the Z-direction spring constant of the removable framework connecting portion 211a of mirror device 2g and catoptron connecting portion 221a is set as, greater than the removable framework connecting portion 211b of mirror device 2f and the Z-direction spring constant of catoptron connecting portion 211b.
On-Y direction among the mirror device 2h adjacent with mirror device 2c, under original state, its catoptron 230 is similar to catoptron 230 among mirror device 2c and the 2g in the inclination of directions X, and is similar to catoptron 230 among mirror device 2d and the 2f in the inclination of Y direction.For example, if the removable framework connecting portion 211b of mirror device 2c, 2d, 2f, 2g and 2h and catoptron connecting portion 221b have identical Z-direction spring constant, then the removable framework connecting portion 211a of mirror device 2h has the identical Z-direction spring constant of removable framework connecting portion 211a with mirror device 2d and 2f.In addition, the catoptron connecting portion 2h of mirror device 2h has the Z-direction spring constant identical with the catoptron connecting portion 221a of mirror device 2c and 2g.
As mentioned above, removable framework connecting portion 211a and 211b and catoptron connecting portion 221a and 221b have the spring constant that depends on the position in the reflection mirror array 700 and set.When electrode 340a to 340d applies the bias voltage with even amplitude, the catoptron 230 of each mirror device 2 of reflection mirror array 700 all tilts, so as with the beam reflection that receives to the catoptron of opposition reflection mirror array center.Identical in this reflective operation and the 9th embodiment with reference to the described reflective operation of Figure 30.
Figure 30 is the cross-sectional view of getting along the line II-II among Figure 37.Figure 30 illustrates in reflection mirror array 510 and 520 cross section of the catoptron 230 of a plurality of mirror devices 2 of arranging, reflection mirror array 510 and 520 each all comprise reflection mirror array 700.Each of the catoptron 511 to 515 of reflection mirror array 510 and the catoptron 521 to 525 of reflection mirror array 520 is all corresponding to the catoptron 230 of mirror device 2 included in the above-mentioned reflection mirror array 700. Reflection mirror array 510 and 520 shown in Figure 30 corresponds respectively to the reflection mirror array 510 and 520 of photoswitch shown in Figure 29 600.
As mentioned above, in the present embodiment, removable framework connecting portion 211a has the spring constant different with corresponding connection parts with each of 211b and catoptron connecting portion 221a and 221b.Because mirror tilt one predetermined angular under original state, so the mirror tilt angle can be little.
By with above-mentioned the 9th embodiment in identical manufacture method, make mirror device and reflection mirror array according to present embodiment.
In the present embodiment, in monocrystalline silicon layer, form in the groove process of the shape that meets frame section 210, removable framework connecting portion 211a and 211b, removable framework 220, catoptron connecting portion 221a and 221b and catoptron 230, position in depending on reflection mirror array changes in the spring constant, forms removable framework connecting portion 211a and 211b and catoptron connecting portion 221a and 221b.
According to the position in the reflection mirror array 700, regulate the removable framework connecting portion 211a of each mirror device 2 of reflection mirror array 700 of such manufacturing and the spring constant of 211b and catoptron connecting portion 221a and 221b.In case 340a to 340d applies predetermined bias to electrode, each mirror device just all beam reflection to the catoptron of opposition reflection mirror array 800 centers.This allows to reduce the pitch angle of the catoptron 230 of each mirror device 2.
Figure 38 shows the modification of mirror substrate 200.In the present embodiment, as mentioned above, removable framework connecting portion 211a and 211b are set in the removable framework 220 among the formed first notch 222a and 222b.Yet removable framework connecting portion 211a and 211b not necessarily need to be arranged in this first notch 222a and 222b, but can be arranged in frame section 210 formed the 3rd notch 224a and 224b, as shown in figure 38.
In the present embodiment, reflection mirror array 700 shown in Figure 37 has 5 * 5 mirror devices 2.Yet the number of set mirror device 2 is not limited to 5 * 5 in the reflection mirror array 700, but can arbitrarily be provided with as required.The reflection mirror array 800 of present embodiment can have the structure identical with reflection mirror array 700.
In the present embodiment, by regulating the Z-direction spring constant of torsion spring included in each of removable framework connecting portion 211a and 211b and catoptron connecting portion 221 and 221b, catoptron 230 is had a down dip in original state.Otherwise, can regulate around the spring constant of torsion spring X-axis rotation.Even catoptron 230 is had a down dip in original state.
In the present embodiment, apply bias voltage and displacement voltage to electrode 340a to 340d.Yet, can only apply displacement voltage.
As mentioned above, according to present embodiment, each connecting portion all has the structure different with corresponding connection parts, makes to make mirror tilt one predetermined angular according to the bias voltage that puts on electrode.Because make mirror tilt by under this heeling condition, applying control voltage, so the mirror tilt angle can be little.Even when inclined mirror significantly, catoptron also can under low pressure be operated.
[the 11 embodiment]
Next eleventh embodiment of the invention will be described.Present embodiment reduces the mirror tilt angle by electrode being arranged on the substrate about on the asymmetric position of the turning axle that reaches the catoptron on the electrode base board.Represent same composition element in the 11 embodiment with identical Reference numeral in the 8th to the tenth embodiment.Show to Figure 39 A and 39B major part the mirror device 2 of catoptron as the reflection mirror array component units.In the present embodiment, will the mirror device of the plate electrode with no any teat be described for example.
As shown in figure 40, in conventional mirror device 8200, electrode 8340a to 8340d is formed on the base portion 8310 and rotates axisymmetric position about removable framework turning axle and the catoptron that reaches the catoptron 8230 on the electrode base board 8301.Therefore, as shown in figure 40, the central shaft of the central shaft of catoptron 8230 (indicated) and electrode 8340a to 8340d by the alternately length dotted line among Figure 40 (by among Figure 40 alternately the unexpected misfortune dotted line is indicated) coupling.Therefore, when when electrode 8340a to 8340d applies even voltage, attractive force will act on entire emission mirror 8230 uniformly.Catoptron 8230 almost is parallel to the first type surface of the base portion 8310 of electrode base board 8301, promptly almost perpendicular to the central shaft of catoptron 8230.The central shaft of catoptron 8230 represents by catoptron 8230 centers, and perpendicular to catoptron 8230 planes, promptly be parallel to range direction between mirror substrate 8201 and the electrode base board 8301 straight line.The center of electrode 8340a to 8340d is passed through in the central shaft indication of electrode 8340a to 8340d, and perpendicular to electrode 8340a to 8340d plane, promptly is parallel to the straight line of range direction between mirror substrate 8201 and the electrode base board 8301.
On the contrary, in the mirror device 2 of present embodiment, electrode 340a to 340d is formed on the base portion 310 about the removable framework turning axle that reaches the catoptron 230 on the electrode base board 300 and catoptron turning axle asymmetric position one of at least.Therefore, as shown in figure 41, the central shaft of catoptron 230 (indicated by the alternately length dotted line among Figure 41) does not match with the central shaft (indicated by the unexpected misfortune dotted line among Figure 41) of electrode 340a to 340d.Therefore, when applying even voltage (following will be called bias voltage) to electrode 340a to 340d, attractive force will act on the part in the face of electrode 340a to 340d.Catoptron 230 is from the state (indicated by the dotted line Figure 41) perpendicular to central shaft, the predetermined angular that tilted (this will be called " original state " below state).In the present embodiment, apply independent control voltage, catoptron 230 is tilted by the electrode 340a to 340d under this state.
Next will be described with reference to Figure 42 reflection mirror array according to present embodiment.In reflection mirror array 800, arrange two-dimensionally with matrix form with reference to figure 39A, 39B and 41 described mirror devices 2 according to present embodiment.Reflection mirror array 800 is corresponding to the reflection mirror array 510 and 520 of photoswitch shown in Figure 29 600.In reflection mirror array 800, the electrode 340a to 340d of each mirror device (indicated by the dotted line among Figure 42) is formed on the electrode base board 300 about reaching the asymmetric position of turning axle of the catoptron 230 on the electrode base board 300, make catoptron 230 under original state with beam reflection to the catoptron that is positioned at opposition reflection mirror array center.Also might pass through bias voltage amplitude, the inclination that comes accommodation reflex mirror 230.
For example, in reflection mirror array shown in Figure 42 800, the electrode 340a to 340d of each mirror device 2 is positioned at the mirror device 2a of reflection mirror array 800 centers is connected on the straight line at catoptron 230 centers of mirror device 2.When the distance of distance mirror device 2a increases, the position of the electrode 340a to 340d of each mirror device 2 just from the catoptron 230 of mirror device 2 opposite side of mind-set mirror device 2a depart from.Along with the distance between mirror device 2a and the mirror device 2 increases, this layout has increased the inclination of catoptron 230.The central shaft of the electrode 340a to 340d of mirror device 2a and the central shaft of catoptron 230 coupling.When the electrode 340a to 340d to each mirror device 2 of reflection mirror array 800 applied the bias voltage with even amplitude, catoptron 230 tilted, so as with the beam reflection that receives to the catoptron of opposition reflection mirror array center.This reflective operation with reference to identical in described the 9th embodiment of Figure 30.
Figure 30 is the cross-sectional view of getting along the line I-I among Figure 42.Figure 30 illustrates in reflection mirror array 510 and 520 cross section of the catoptron 230 of a plurality of mirror devices 2 of arranging, reflection mirror array 510 and 520 each all comprise reflection mirror array 800.Each of the catoptron 511 to 515 of reflection mirror array 510 and the catoptron 521 to 525 of reflection mirror array 520 is all corresponding to above-mentioned catoptron 230. Reflection mirror array 510 and 520 shown in Figure 30 corresponds respectively to the reflection mirror array 510 and 520 of photoswitch shown in Figure 29 600.
As mentioned above, in the present embodiment, might reduce the mirror tilt angle.This allows to reduce the driving voltage of mirror device and reflection mirror array.
By with above-mentioned the 9th embodiment in identical manufacture method, make mirror device and reflection mirror array according to present embodiment.
In the present embodiment, by known photoetching and etching metal film is being carried out patterning, so that form in the step of electrode 340a to 340d, lead-in wire 341a to 341d and distribution 370, depend on the position in the reflection mirror array 800, electrode 340a to 340d is formed on the position of departing from base portion 310 centers.The electrode 340a to 340d that is positioned at the mirror device 2 at reflection mirror array 800 centers is formed on the almost center of base portion 310.Utilize this technology, form electrode base board 300 with above-mentioned shape.
According to the position in the reflection mirror array 800, regulate the position of electrode 340a to 340d of each mirror device 2 of the reflection mirror array 800 of such manufacturing.In case 340a to 340d applies bias voltage to electrode, each mirror device just all beam reflection to the catoptron of opposition reflection mirror array 800 centers.This allows to reduce the pitch angle of the catoptron 230 of each mirror device 2.In addition, because catoptron 230 has a down dip in original state, so the opereating specification of catoptron 230 is little, so low voltage drive is possible.
As mentioned above, according to present embodiment, electrode is set on the substrate about the asymmetric optional position of the turning axle that reaches the catoptron on the electrode base board.By putting on the bias voltage of electrode, make mirror tilt one predetermined angular.Because by apply control voltage under heeling condition, make mirror tilt, the mirror tilt angle can be little.Because the pitch angle is little, so low voltage drive is possible.
[the 12 embodiment]
Next twelveth embodiment of the invention will be described.In the present embodiment, teat is set on the electrode base board 300 of the 11 embodiment, and electrode 340a to 340d is set on this teat and the electrode base board 300, shown in Figure 43 and 44.Therefore, represent same composition element in the 12 embodiment with title identical in the 11 embodiment and Reference numeral, and will omit description of them as required.
The catoptron 230 with opposition mirror substrate 200 that four sector electrode 340a to 340d are formed on base portion 310 upper surfaces that comprise teat 320 outside surfaces has in the circle of identical size.The mirror device of seeing from upside 2, almost mate with the center of pivot 330 at the center of electrode 340a to 340d.As mentioned above, the position in the reflection mirror array 800 is depended on and the center of departing from base portion 310 in the position of teat 320.Because central shaft does not match, so when upside was seen, electrode 340a to 340d was partly overlapping each other with catoptron 230.
In the mirror device 2 of present embodiment, the central shaft of catoptron 230 (indicated) by the alternately length dotted line among Figure 44 departed from the teat 320 that has electrode 340a to 340d on the surface central shaft (by among Figure 44 alternately the unexpected misfortune dotted line is indicated), as shown in figure 44.Therefore, when when electrode 340a to 340d applies even bias voltage, catoptron 230 will be from state (indicated by the dotted line Figure 44) inclination one predetermined angular (this will be called " original state " below state) perpendicular to central shaft.In the present embodiment, apply independent control voltage, catoptron 230 is tilted by the electrode 340a to 340d under this state.
By arranging mirror device 2 two-dimensionally, form reflection mirror array shown in Figure 42 800 with matrix form.In reflection mirror array 800 with mirror device 2 shown in Figure 42, the central shaft of the teat 320 of each mirror device 2 and the central shaft of electrode 340a to 340d all are positioned at, and the mirror device 2a of reflection mirror array 800 centers are connected on the straight line at catoptron 230 centers of mirror device 2.When the distance of distance mirror device 2a increased, departed to the opposite side of mirror device 2a gradually from catoptron 230 centers of mirror device 2 position of these central shafts.The central shaft coupling of the central shaft of the teat 320 of mirror device 2a and the central shaft of electrode 340a to 340d and catoptron 230.When the electrode 340a to 340d to each mirror device 2 of reflection mirror array 800 applied bias voltage equably, catoptron 230 tilted, so as with the beam reflection that receives to the catoptron of opposition reflection mirror array center.This allows to have reduced the mirror tilt angle according to the reflection mirror array of present embodiment.
Next a kind of method of making according to the reflection mirror array of present embodiment will be described.The same in the method for making mirror substrate 200 and the 11 embodiment.
In the present embodiment, in the step that forms base portion 310, first and second steps 321 and 322, pivot 330 and jut 360a and 360b, depend on the position in the reflection mirror array, teat 320 is formed on the position of departing from base portion 310 centers.The teat 320 that is positioned at the mirror device 2 at reflection mirror array 800 centers is formed on almost base portion 310 centers.Utilize this technology, form electrode base board 300 with above-mentioned shape.
According to the position in the reflection mirror array 800, regulate the position of teat 320 of each mirror device 2 of the reflection mirror array 800 of such manufacturing, i.e. the position of electrode 340a to 340d.In case apply even bias voltage to electrode 340a to 340d, each mirror device just all beam reflection to the catoptron of opposition reflection mirror array 800 centers.This allows to reduce the pitch angle of the catoptron 230 of each mirror device 2.
In the 11 and the 12 embodiment, reflection mirror array 800 shown in Figure 42 has 5 * 5 mirror devices 2.Yet the number of set mirror device 2 is not limited to 5 * 5 in the reflection mirror array 800, but can come as required arbitrarily to be provided with.
According to the 11 and the catoptron 230 of the mirror device 2 of the 12 embodiment not only tilt one-dimensionally as Figure 30, and tilt two-dimensionally about removable framework turning axle and catoptron turning axle.Therefore, according to the position of mirror device 2 in the reflection mirror array 800, come the electrode 340a to 340d and the position of teat 320 on electrode base board 300 of accommodation reflex mirror device 2 two-dimensionally.
According to the 11 and the mirror device 2 and the reflection mirror array of the 12 embodiment not only can be used in the photoswitch, and can be used in measuring element, display and the scanner.In this case, according to purposes and the standard used, the teat 320 and the electrode 340a to 340d of mirror device 2 is arranged on the optional position.
In the 11 and the 12 embodiment,, make the central shaft of catoptron 230 depart from the central shaft of teat 320 and electrode 340a to 340d by regulating the position of teat 320 on the electrode base board 300 or electrode 340a to 340d.Yet position that can be by accommodation reflex mirror substrate 200 upper reflectors 230 makes the central shaft of catoptron 230 depart from the central shaft of teat 320 and electrode 340a to 340d.
In the 11 and the 12 embodiment, apply bias voltage and displacement voltage to electrode 340a to 340d.Yet, can only apply displacement voltage.
As mentioned above, according to present embodiment, electrode is positioned on the substrate about the asymmetric optional position of the turning axle that reaches the catoptron on the electrode base board.By putting on the bias voltage of electrode, make mirror tilt one predetermined angular.Because make mirror tilt by under this heeling condition, applying control voltage, so the mirror tilt angle can be little.Because the pitch angle is little, so low voltage drive is possible.
[the 13 embodiment]
Next thirteenth embodiment of the invention will be described.Present embodiment by forbidding mirror device removable framework turning axle and the catoptron turning axle one of at least by the catoptron center of gravity, reduce the mirror tilt angle.Represent same composition element in the 13 embodiment with identical Reference numeral in the 8th to the 12 embodiment.Show to Figure 45 major part the mirror device 2 of catoptron as the reflection mirror array component units.In the present embodiment, the mirror device of the plate electrode with no any teat will be illustrated.
Comprise torsion spring in a zigzag and be set at the first notch 222a of removable framework 220 and among the 222b this is connected to removable framework 220 to removable framework connecting portion 211a and 211b with frame section 210.This structure can be rotated removable framework 220 around passing through this removable framework turning axle to removable framework connecting portion 211a and 211b.In mirror device shown in Figure 45 2, removable framework connecting portion 211a and 211b are connected to frame section 210 and removable framework 220 like this, so that are passed through the center of gravity G of catoptron 230 by the indicated removable framework turning axle of alternately length dotted line k among Figure 45.In the present embodiment, because catoptron 230 is almost circle when upside is seen, so the center of gravity of catoptron 230 is corresponding to the center of gravity of the circle of the outer shape of catoptron 230.
Comprise torsion spring in a zigzag and be set at the second notch 223a of removable framework 220 and among the 223b this is connected to catoptron 230 to catoptron connecting portion 221a and 221b with removable framework 220.This structure can be rotated catoptron 230 around passing through this catoptron turning axle to catoptron connecting portion 221a and 221b.In mirror device shown in Figure 45 2, catoptron connecting portion 221a and 221b are set at, from catoptron turning axle, to the i.e. position of translation on Y direction shown in Figure 45 of removable that side of framework connecting portion 211b by the indicated conventional mirror device that passes through center of gravity G of dotted line l.Because the catoptron turning axle on the Y direction from conventional mirror turning axle l translation, so the catoptron turning axle center of gravity by catoptron 230, as among Figure 45 alternately the unexpected misfortune dotted line is indicated.Removable framework turning axle and catoptron turning axle are with right angle intersection.
Next will operation according to the mirror device of present embodiment be described with reference to Figure 45 to 47.Figure 46 and 47 cross sections corresponding to the major part of getting along the line I-I among Figure 45, and show relation between catoptron turning axle and the catoptron 230.
In conventional mirror device 8200 shown in Figure 46, catoptron connecting portion 8221a and 8221b are arranged to make the center of gravity of catoptron turning axle by catoptron 8230.Therefore, catoptron 8230 is supported symmetrically about the catoptron turning axle.Therefore, when when electrode 8340a to 8340d applies even voltage, attractive force will act on entire emission mirror 8230 uniformly.Catoptron 8230 and removable framework 8220 keep almost being parallel to the state of base portion 8310 simultaneously near base portion 8310 those sides, and be indicated as the dotted line among Figure 46.
On the contrary, in the mirror device 2 of present embodiment shown in Figure 47, because catoptron connecting portion 221a and 221b are set to removable that side of framework connecting portion 211b, the i.e. position of translation on the Y direction, as mentioned above, so catoptron turning axle m does not pass through the center of gravity of catoptron 230.Shown in Figure 45 and 47, on catoptron turning axle m, the distance between catoptron 230 ends of catoptron turning axle and removable that side of framework connecting portion 211a is longer than the distance between catoptron 230 ends of catoptron turning axle and removable that side of framework connecting portion 211b.When making attraction force acts on catoptron 230 in case apply even voltage (following will be called bias voltage), catoptron 230 is near removable framework 220 and base portion 310 those sides, and tilt around the catoptron turning axle, indicated as the dotted line among Figure 47, make the end of removable that side of framework connecting portion 211a more approach base portion 310 those sides (this will be called " original state " below state).In the present embodiment, to this state promptly with Figure 45 in the Y side electrode 340a to 340d under the catoptron 230 terminal states on (following will be called " Y " direction) (this will be called " tilting in-Y direction " below state) in the opposite direction near base portion 310 those sides, apply independent control voltage, catoptron 230 is tilted.
According to the position of mirror device in the reflection mirror array 2, come arbitrarily to be provided with shown in Figure 45 and 47 displacement and the direction of catoptron connecting portion 221a and 221b in the mirror device 2 as required.
In mirror device shown in Figure 45 2, catoptron connecting portion 221a and 221b move on the Y direction simultaneously, to prevent the center of gravity G of catoptron turning axle by catoptron 230.Otherwise one of catoptron connecting portion 221a and 221b can move on the Y direction, to prevent the center of gravity G of catoptron turning axle by catoptron 230.To be described with reference to Figure 48 this situation.Show to Figure 48 major part the mirror substrate of catoptron as the mirror device 2 of reflection mirror array component units.Represent same composition element among Figure 48 with title identical in the mirror device shown in Figure 45 and Reference numeral, and will omit description of them as required.
In mirror device shown in Figure 48 2, catoptron connecting portion 221a is set at, from by the catoptron turning axle of the indicated mirror device that passes through center of gravity G 8200 of the dotted line l Figure 48, to removable that side of framework connecting portion 211b promptly in position that the Y direction is offset.The conventional mirror turning axle l end of that side of catoptron connecting portion 221a moves on the Y direction.That is, do not pass through the center of gravity of catoptron 230 by the catoptron turning axle of the alternately unexpected misfortune dotted line indication among Figure 48.Catoptron turning axle m and removable framework turning axle k be not with right angle intersection.Catoptron turning axle m intersects with any angle and removable framework turning axle k.On removable framework turning axle k, the distance between catoptron 230 ends of catoptron turning axle and removable that side of framework connecting portion 211a is longer than the distance between catoptron 230 ends of catoptron turning axle and removable that side of framework connecting portion 211b.When applying bias voltage to electrode 340a to 340d and make attraction force acts on catoptron 230 with even amplitude, catoptron 230 winds the catoptron turning axle m that intersects with any angle and removable framework turning axle k and tilts, and makes the end of removable that side of framework connecting portion 211a near base portion 310.In the present embodiment, to this original state, promptly with perpendicular to a side of catoptron turning axle m among Figure 48 electrode 340a to 340d under the catoptron 230 terminal states on (following will being called " a direction ") (this will be called " tilting in-a direction " below state) in the opposite direction near base portion 310 those sides, apply independent control voltage, catoptron 230 is tilted.
In mirror device shown in Figure 48 2, catoptron connecting portion 221a moves on the Y direction.Yet catoptron connecting portion 221b can move on the Y direction.According to the position of mirror device in the reflection mirror array 2, come arbitrarily to be provided with the displacement of catoptron connecting portion 221a and 221b as required.According to the position of mirror device in the reflection mirror array 2, come arbitrarily to be provided with catoptron connecting portion 221a and 221b moving direction as required from the catoptron turning axle of conventional mirror device 8200, promptly the Y direction just/negative sign.
Each of catoptron connecting portion 221a and 221b can move on the Y direction.In this case, catoptron connecting portion 221a and 221b can as required and arbitrarily move, as long as the catoptron turning axle does not pass through the center of gravity of catoptron 230.
Next, the mirror device that removable framework turning axle does not pass through the catoptron center of gravity will be described with reference to Figure 49.Show to Figure 49 major part the mirror substrate 200 of catoptron as the mirror device 2 of reflection mirror array component units.Represent same composition element among Figure 49 with title identical in the mirror device shown in Figure 45 and Reference numeral, and will omit description of them as required.
In mirror device shown in Figure 49 2, removable framework connecting portion 211a and 211b are set at, from removable framework turning axle, to the position that side of catoptron connecting portion 221b promptly is offset on directions X by the indicated conventional mirror device 8200 that passes through center of gravity G of the dotted line Figure 49.Indicated as the alternately length dotted line k among Figure 49, on directions X with respect to the removable framework turning axle of the removable framework turning axle of tradition translation the center of gravity by catoptron 230.On removable framework turning axle k, the distance between catoptron 230 ends of removable framework turning axle and that side of catoptron connecting portion 221a is longer than the distance between catoptron 230 ends of removable framework turning axle and that side of catoptron connecting portion 221b.When in case apply predetermined bias and when making attraction force acts on catoptron 230, catoptron 230 tilts around removable framework turning axle, make close base portion 310 those sides of end of that side of catoptron connecting portion 221a to electrode 340a to 340d.In the present embodiment, to this original state, promptly the end of the direction opposite with directions X among Figure 49 (following will be called " directions X ") is near the electrode 340a to 340d under the state (this will be called " directions X tilts " below state) of base portion 310 those sides, apply independent control voltage, catoptron 230 is tilted.
In mirror device shown in Figure 49 2,, come arbitrarily to be provided with the displacement of removable framework connecting portion 211a and 211b as required according to the position of mirror device in the reflection mirror array 2.According to the position of mirror device in the reflection mirror array 2, come arbitrarily to be provided with removable framework connecting portion 211a and 211b moving direction as required from the removable framework turning axle of conventional mirror device 8200, promptly directions X just/negative sign.
With the same among Figure 48, in mirror device shown in Figure 49 2, one of removable framework connecting portion 211a and 211b can move, to prevent the center of gravity of removable framework turning axle by catoptron 230.In this case, when in case apply even bias voltage and when making attraction force acts on catoptron 230 to electrode 340a to 340d, catoptron 230 will wind the removable framework turning axle that intersects with any angle and catoptron turning axle and tilt, and make the end of one of catoptron connecting portion 221a and 221b that side near base portion 310 those sides.Even in this case,, come arbitrarily to be provided with displacement and the direction of removable framework connecting portion 211a and 211b as required also according to the position of mirror device in the reflection mirror array 2.
Each of removable framework connecting portion 211a and 211b can move on directions X.In this case, removable framework connecting portion 211a and 211b can arbitrarily move as required, as long as removable framework turning axle does not pass through the center of gravity of catoptron 230.
Next, the mirror device that removable framework turning axle and catoptron turning axle do not pass through catoptron center of gravity G will be described with reference to Figure 50.Show to Figure 50 major part the mirror substrate 200 of catoptron as the mirror device 2 of reflection mirror array component units.Represent same composition element among Figure 50 with title identical in the mirror device shown in Figure 45 and 49 and Reference numeral, and will omit description of them as required.
In mirror device shown in Figure 50 2, removable framework connecting portion 211a and 211b are set at, from removable framework turning axle, to the position that side of catoptron connecting portion 221b promptly is offset on directions X by the indicated conventional mirror device 8200 that passes through center of gravity G of the dotted line n Figure 50.Catoptron connecting portion 221a and 221b are set at, from the catoptron turning axle by the indicated conventional mirror device 8200 that passes through center of gravity G of the dotted line l Figure 50, to the position that removable that side of framework connecting portion 211b promptly is offset on the Y direction.By the indicated removable framework turning axle of length dotted line k alternately and by the indicated catoptron turning axle of unexpected misfortune dotted line m alternately the center of gravity by catoptron 230 because they respectively on X and Y direction with respect to tradition removable framework turning axle n and catoptron turning axle l translation.On removable framework turning axle k, the distance between catoptron 230 ends of removable framework turning axle and that side of catoptron connecting portion 221a is longer than the distance between catoptron 230 ends of removable framework turning axle and that side of catoptron connecting portion 221b.On catoptron turning axle m, the distance between catoptron 230 ends of catoptron turning axle and removable that side of framework connecting portion 211a is longer than the distance between catoptron 230 ends of catoptron turning axle and removable that side of framework connecting portion 211b.When applying predetermined bias to electrode 340a to 340d and make attraction force acts on catoptron 230, catoptron 230 tilts around removable framework turning axle k and catoptron turning axle m, make with Figure 50 in a side in the opposite direction the end of (following will be called " a " direction) near base portion 310 those sides (this will be called " inclination on a direction " below state).In the present embodiment, the electrode 340a to 340d under this original state applies independent control voltage, and catoptron 230 is tilted.
In mirror device shown in Figure 50 2,, come arbitrarily to be provided with the displacement of removable framework connecting portion 211a and 211b and catoptron connecting portion 221a and 221b as required according to the position of mirror device in the reflection mirror array 2.According to the position of mirror device in the reflection mirror array 2, come arbitrarily to be provided with the moving direction of removable framework connecting portion 211a and 211b and catoptron connecting portion 221a and 221b as required, promptly X and Y direction just/negative sign.
In mirror device shown in Figure 50 2, removable framework connecting portion 211a and 211b and catoptron connecting portion 221a and 221b move on the Y direction simultaneously, to prevent removable framework turning axle and the catoptron turning axle center of gravity G by catoptron 230.Otherwise one of removable framework connecting portion 211a and 211b and one of catoptron connecting portion 221a and 221b can move, to prevent the center of gravity G of catoptron turning axle by catoptron 230.
Next will reflection mirror array according to present embodiment be described with reference to Figure 51.Figure 51 shows the state that applies predetermined bias to electrode 340a to 340d.Each mirror device shown in Figure 51 all is in the state shown in the Figure 45,48,49 or 50 that sees from the front.That is, each mirror device all has catoptron connecting portion 221a on the horizontal direction and removable framework connecting portion 211a and the 211b on 221b and the vertical direction.
In reflection mirror array 900, arrange two-dimensionally with matrix form with reference to Figure 45,48,49 and 50 described mirror devices 2 according to present embodiment.Reflection mirror array 900 is corresponding to the reflection mirror array 510 and 520 of photoswitch shown in Figure 29 600.In reflection mirror array 900, at least one of removable framework connecting portion 211a and 211b and catoptron connecting portion 221a and 221b is formed on the position of not passing through catoptron 230 centers of gravity, make applying to electrode 340a to 340d under the original state of even bias voltage, catoptron 230 beam reflection to the catoptron that is positioned at opposition reflection mirror array center.At the mirror device 2a that is arranged in reflection mirror array 900 centers, removable framework connecting portion 211a and 211b and catoptron connecting portion 221a and 221b are formed like this, so that removable framework turning axle and catoptron turning axle are by catoptron 230 centers of gravity, simultaneously with right angle intersection.
For example, the same with mirror device 2 shown in Figure 45, on the Y direction among the mirror device 2b adjacent with mirror device 2a, from center of gravity G skew, so that catoptron 230 tilts in-Y direction under original state on+Y direction for catoptron connecting portion 221a and 221b.On the Y direction among the mirror device 2c adjacent with mirror device 2b, catoptron connecting portion 221a and the 221b amount of movement on+Y direction is greater than catoptron connecting portion 221a and the 221b of mirror device 2b, thus under original state the pitch angle of catoptron 230 on-Y direction of mirror device 2c greater than the catoptron 230 of catoptron 2b.
The same with mirror device 2 shown in Figure 49, in the directions X mirror device 2d adjacent with mirror device 2a, from center of gravity G skew, so that catoptron 230 tilts at-directions X under original state on+directions X for removable framework connecting portion 211a and 211b.On directions X among the mirror device 2e adjacent with mirror device 2d, removable framework connecting portion 211a and the 211b amount of movement on+directions X is greater than removable framework connecting portion 211a and the 211b of mirror device 2d, thus under original state the pitch angle of catoptron 230 on-directions X of mirror device 2e greater than the catoptron 230 of mirror device 2d.
The same with mirror device 2 shown in Figure 48, in X and Y direction, be among the mirror device 2f adjacent on the arrow a direction among Figure 50 with mirror device 2a, catoptron connecting portion 221a is offset from center of gravity G on+Y direction, so that catoptron 230-X and-the Y direction, the pitch angle on promptly opposite with arrow a among Figure 50 direction is greater than the catoptron 230 of mirror device 2a.On a direction among the mirror device 2g adjacent with mirror device 2f, the amount of movement of catoptron connecting portion 221a on+Y direction be greater than the catoptron connecting portion 221a of mirror device 2f, thus under original state the pitch angle of catoptron 230 on-a direction of mirror device 2g greater than the catoptron 230 of mirror device 2f.
In mirror device 2f and 2g, removable framework connecting portion 211a can move on+directions X.In mirror device 2f and 2g, removable framework connecting portion 211a and 211b and catoptron connecting portion 221a and 221b can be respectively+X and+move on the Y direction.In mirror device 2f and 2g, removable framework connecting portion 211a and catoptron connecting portion 221a can be respectively+Y and+move on the directions X.
As mentioned above, according to the position of mirror device in the reflection mirror array 900, the position of removable framework connecting portion 211a and 211b and catoptron connecting portion 221a and 221b is set.When electrode 340a to 340d applies the bias voltage with even amplitude, the catoptron 230 of each mirror device 2 of reflection mirror array 900 all tilts, so that a beam reflection of receiving is to the catoptron of opposition reflection mirror array center.This reflective operation with reference to identical in described the 9th embodiment of Figure 30.
Figure 30 is the cross-sectional view of getting along the line II-II among Figure 51.Figure 30 illustrates in reflection mirror array 510 and 520 cross section of the catoptron 230 of a plurality of mirror devices 2 of arranging, reflection mirror array 510 and 520 each all comprise reflection mirror array 900.Each of the catoptron 511 to 515 of reflection mirror array 510 and the catoptron 521 to 525 of reflection mirror array 520 is all corresponding to catoptron 230 included in the above-mentioned reflection mirror array 900. Reflection mirror array 510 and 520 shown in Figure 30 corresponds respectively to the reflection mirror array 510 and 520 of photoswitch shown in Figure 29 600.
As mentioned above, in the present embodiment, removable framework connecting portion 211a and 211b and catoptron connecting portion 221a and 221b are set like this, so that removable framework turning axle and the catoptron turning axle center of gravity by catoptron 230 not one of at least.Because catoptron is at the original state predetermined angular that has a down dip, so the mirror tilt angle can be little.Therefore, the driving voltage of mirror device and reflection mirror array can be low.
By with above-mentioned the 9th embodiment in identical manufacture method, make according to this execute the example mirror device and reflection mirror array.
In the present embodiment, in monocrystalline silicon layer, form in the groove of the shape that meets frame section 210, removable framework connecting portion 211a and 211b, removable framework 220, catoptron connecting portion 221a and 221b and catoptron 230, form removable framework connecting portion 211a and 211b and catoptron connecting portion 221a and 221b like this, so that depend on the position in the reflection mirror array, their position is offset on above-mentioned X and Y direction.
According to the position of mirror device in the reflection mirror array 900, regulate the removable framework connecting portion 211a of each mirror device 2 of reflection mirror array 900 of such manufacturing and the position of 211b and catoptron connecting portion 221a and 221b.In case 340a to 340d applies predetermined bias to electrode, each mirror device just all beam reflection to the catoptron of opposition reflection mirror array center.This allows to reduce the pitch angle of the catoptron 230 of each mirror device 2.In addition, because catoptron 230 has a down dip in original state, so the opereating specification of catoptron 230 is little, so low voltage drive is possible.
Figure 38 shows the modification of mirror substrate 200.In the present embodiment, as mentioned above, removable framework connecting portion 211a and 211b are set in the removable framework 220 among the formed first notch 222a and 222b.Yet removable framework connecting portion 211a and 211b not necessarily need to be positioned at herein, and can be arranged in frame section 210 formed the 3rd notch 224a and 224b, as shown in figure 38.Even in mirror substrate 200, also might reduce the pitch angle of catoptron 230 by preventing removable framework turning axle and catoptron turning axle center of gravity by catoptron 230.
In the present embodiment, the reflection mirror array shown in Figure 51 900 has 5 * 5 mirror devices 2.Yet the number of set mirror device 2 is not limited to 5 * 5 in the reflection mirror array 900, but can arbitrarily be provided with as required.
In the present embodiment, apply bias voltage and displacement voltage to electrode 340a to 340d.Yet, can only apply displacement voltage.
As mentioned above, according to present embodiment, because the catoptron turning axle is by center of gravity, so in case apply bias voltage to electrode, the catoptron predetermined angular that just tilts.Because make mirror tilt by under this heeling condition, applying control voltage, so the mirror tilt angle can be little.Because the pitch angle is little, so low voltage drive is possible.
[the 14 embodiment]
Next fourteenth embodiment of the invention will be described.
Though it is not shown in Figure 107 and 108, but when reflection mirror array comprises the integrated a plurality of catoptrons 8103 (mirror device) of two dimension, by convention, be used near distribution that the drive electrode 8003-1 to 8003-4 of second mirror device provides voltage catoptron 8103 by given mirror device (following will be called first mirror device).Because apply driving voltage, so the catoptron 8103 of first mirror device is also from receiving the electrostatic force from distribution to distribution.Therefore, the tiltangle value of catoptron 8103 has departed from the suitable angle that voltage determined by the drive electrode 8003-1 to 8003-4 that puts on first mirror device.In addition, the driving voltage that puts on the drive electrode 8003-1 to 8003-4 of second mirror device becomes with the state of photoswitch at any time.Therefore, because distribution to the influence of a plurality of second mirror devices, is difficult to control the pitch angle of the catoptron 8103 of first mirror device.
If catoptron 8103 exceedingly separates with distribution, then this interference from distribution is negligible.This has increased the layout spacing of catoptron 8103, and has increased the size of entire emission lens array wastefully.In photoswitch, a pair of reflection mirror array exchange light beam respect to one another.If the catoptron layout spacing in the reflection mirror array has increased, then each catoptron 8103 required tiltangle also will increase, thereby feasible being difficult to makes.Need arrange a plurality of catoptrons 8103 near as far as possible.If can come distribution is guided to the lower face side of infrabasal plate 8001 by in infrabasal plate 8001, forming upright opening with drive electrode 8003-1 to 8003-4, then might suppress the interference of distribution, simultaneously a plurality of catoptrons 8103 are arranged near.Yet the lower face side of distribution being guided to infrabasal plate 8001 is difficult technically.That is, in the mill, preferably distribution is formed two-dimensionally on the surface of infrabasal plate 8001.Yet if distribution is positioned near the catoptron 8103, distribution is very important to the interference of catoptron 8103.
For addressing the above problem present embodiment has been proposed, the purpose of present embodiment is, inhibitory reflex mirror device and comprise in the reflection mirror array of a plurality of mirror devices of two-dimensional arrangement, because near the caused mirror tilt of the interference angle of distribution is unexpected changes.
In the present embodiment, shown in Figure 52 and 53, four drive electrode 1003-1 to 1003-4 are set at the center of the infrabasal plate of being made by monocrystalline silicon 1001.Monocrystalline silicon pillar 1004 is set at the both sides of infrabasal plate 1001 upper surfaces.
Separately make the structure of the infrabasal plate 1001 shown in Figure 52 and 53 and the structure of upper substrate 1101.Upper substrate 1101 is welded on the pillar 1004, makes upper substrate 1101 join on the infrabasal plate 1001.In this mirror device, make catoptron 1103 ground connection.1003-1 to 1003-4 applies positive voltage to drive electrode, so that it is poor to produce asymmetric potential between drive electrode 1003-1 to 1003-4.Electrostatic force attracts catoptron 1103, and it is rotated in any direction.
In the present embodiment, distribution 1005-1 to 1005-4 is formed on the upper substrate 1101.Distribution 1005-1 to 1005-4 is connected respectively to drive electrode 1003-1 to 1003-4, so that provide driving voltage from the power supply (not shown) to drive electrode 1003-1 to 1003-4.Distribution 1006 be connected to mirror device shown in Figure 52 and 53 in the drive electrode (not shown) of formed other mirror device on the same substrate 1001 and 1101 so that provide driving voltage to these drive electrodes.
In the mirror device shown in Figure 52 and 53, if distribution 1005-1 to 1005-4 and 1006 extends on the direction that is parallel to X and Y-axis, then they influence generation around rotatablely moving of Y-axis around X-axis and catoptron 1103 strongly to gimbals 1102.Especially, distribution 1005-1 to 1005-4 and 1006 influences the gimbals 1102 of catoptron 1103 outsides easily.This is because gimbals 1102 are than catoptron 1103 more close distribution 1005-1 to 1005-4 and 1006.
On the other hand, if distribution 1005-1 to 1005-4 and 1006 is positioned at the direction perpendicular to X-axis, then they disturb gimbals 1102 rotatablely moving around X-axis hardly.Similar, if distribution 1005-1 to 1005-4 and 1006 is positioned at the direction perpendicular to Y-axis, their noisy reflection mirror 1103 rotatablely moving hardly then around Y-axis.
In the present embodiment, because emphasis suppresses the influence of distribution 1005-1 to 1005-4 and 1006 pairs of easy affected gimbals 1102, so distribution 1005-1 to 1005-4 and 1006 is arranged on the Y direction perpendicular to gimbals 1102 turning axles.As will be described, by increasing the distance between catoptron 1103 and distribution 1005-1 to 1005-4 and 1006, suppress the influence that catoptron 1103 is rotatablely moved.
When the pitch angle of catoptron 1103 control accuracy be approximately total pitch angle 1/1000 the time, in the identical or littler number of degrees, distribution 1005-1 to 1005-4 and 1006 influence are allowed.When diameter is 10 * 10 catoptrons 1103 of for example 500 μ m during with the 1mm pitch arrangement, the precision at about 1/1000 total pitch angle is corresponding to the light-beam position precision of about 10 μ m.
Below with reference to Figure 54 and 55, describe from the electrostatic force of distribution actual measured results to the influence of catoptron 1103.With reference to Figure 54, horizontal ordinate is represented the horizontal range h of the end of catoptron 1103 to distribution, and ordinate representative is by the skew from the catoptron that electrostatic force produced 1103 pitch angle of distribution.The rotating spring rigidity of torsion spring 1105 is 2.4 * 10
-9Nm, the voltage that puts on distribution is 80 volts, the width W of distribution is 9 μ m, and between catoptron 1103 and the drive electrode 1003-1 to 1003-4 is 87.8 μ m apart from d.
The actual measured results that is obtained is the family curve A1 among Figure 54 under these conditions.Under actual service conditions, the driving voltage maximum for example is approximately 240 volts.When driving voltage was 240 volts, family curve A1 became the family curve A2 among Figure 54.In family curve A2, the angular deflection of catoptron 1103 approximately is 9 times of family curve A1.Family curve A1 and A2 obtain under the supposition that only has a distribution.When applying 240 volts driving voltage, family curve A1 becomes the family curve A3 among Figure 54 to 12 distributions (total distribution width W is 200 μ m).In family curve A3, the angular deflection of catoptron 1103 approximately is 30 times of family curve A1.
Obviously find out as the family curve A3 from Figure 54, when horizontal range h equal between catoptron 1103 and the drive electrode 1003-1 to 1003-4 apart from d the time, compare with the situation of h=0, angular deflection approximately reduces an order of magnitude.When h=2d, to compare with the situation of h=0, angular deflection approximately reduces 2 orders of magnitude.When h=4d, angular deflection approximately reduces 3 orders of magnitude.This result indication, when distribution 1005-1 to 1005-4 and 1006 was separated by for example about 4d with catoptron 1103, the influence of distribution was reduced in fact negligible rank.
Therefore, in the present embodiment, can suppress because the accident at the caused catoptron of interference 1103 pitch angle of distribution 1005-1 to 1005-4 and 1006 changes by distribution 1005-1 to 1005-4 and 1006 being arranged on the direction perpendicular to gimbals 1102 turning axles.When distribution 1005-1 to 1005-4 and 1006 and catoptron 1103 when separating, this inhibition effect can be further enhanced.In the single-rotation axis mirror device without any gimbals, distribution 1005-1 to 1005-4 and 1006 is set on the direction perpendicular to catoptron 1103 turning axles.
As mentioned above, according to present embodiment, in having the single-rotation axis mirror device that is supported for the catoptron that rotates with respect to upper substrate, the turning axle of the distribution that is connected to drive electrode perpendicular to catoptron is arranged on the infrabasal plate, suppresses thus because the unexpected variation in the caused mirror tilt of the interference angle of distribution.In addition, because needn't form distribution in the lower face side of infrabasal plate, thus can be when keeping easy manufacturing, the variation at inhibitory reflex mirror pitch angle.
According to present embodiment, have the annular gimbals and the catoptron that is supported for respect to the gimbals rotation that are supported for respect to the upper substrate rotation, and wind in the bispin rotating shaft mirror device that two axles with right angle intersection rotate, the turning axle of the distribution that is connected to drive electrode perpendicular to gimbals is arranged on the infrabasal plate, suppresses thus because the unexpected variation in the caused mirror tilt of the interference angle of distribution.In addition, because needn't form distribution in the lower face side of infrabasal plate, thus can be when keeping easy manufacturing, the variation at inhibitory reflex mirror pitch angle.
[the 15 embodiment]
In the 14 embodiment, the distribution of single mirror device has been described.In the 15 embodiment, the distribution of the reflection mirror array of a plurality of mirror devices that comprise two-dimensional arrangement will be described with reference to Figure 56.Represent same section among Figure 56 with Reference numeral identical in Figure 52 and 53.With reference to Figure 56, distribution 1007 is connected to the drive electrode (distribution 1007 is corresponding to the distribution 1005-1 to 1005-4 in Figure 52 and 53 and 1006) of each mirror device.The electrode terminal 1008 that is used for wire bond (wire bonding) is connected to distribution 1007.
In the reflection mirror array shown in Figure 56, the electrode terminal 1008 that is connected to external power source is arranged in the periphery that rectangular mirror is arranged district 1201.Distribution 1007 extends to the center from electrode terminal 1008.This has realized distribution layout efficiently.
In the present embodiment, two diagonal line 1202 and 1203 arrange that with catoptron district 1201 is divided into four subregions 1204 to 1207.In any two adjacent sectors that two intersection edges of being arranged district 1201 by catoptron and diagonal line 1202 and 1203 are surrounded, mirror device all is arranged to make the turning axle (by the axle of a pair of torsion spring 1104) of gimbals 1102 with right angle intersection.For example, in Figure 56, the turning axle of the gimbals 1102 of subregion 1204 is set up in the horizontal direction.The turning axle of the gimbals 1102 of the subregion 1205 adjacent with subregion 1204 is set up in vertical direction in Figure 56.With the same in the 14 embodiment, in subregion 1204 to 1207, distribution 1007 extends perpendicular to the turning axle of gimbals 1102.
Like this, present embodiment can suppress because the accident at the caused catoptron of interference 1103 pitch angle of distribution 1007 changes.
As mentioned above, according to present embodiment, in the reflection mirror array of a plurality of bispin rotating shaft mirror devices, arrange that by rectangular mirror the mirror device in two intersection edges in district and any two adjacent sectors that diagonal line is surrounded all comprises the gimbals of turning axle with right angle intersection with two-dimensional arrangement.In each subregion, the distribution that is connected to drive electrode extends on infrabasal plate perpendicular to the turning axle of gimbals.This structure can suppress because the anything unexpected at the caused mirror tilt of the interference angle of distribution changes.
[the 16 embodiment]
Next sixteenth embodiment of the invention will be described.The conductive component of present embodiment by handle and catoptron equipotentiality is arranged in the position than the more close distribution of catoptron, suppresses because the accident at the caused mirror tilt of the interference angle of distribution changes.Represent same composition element in the 16 embodiment with title identical in the 14 embodiment.
Shown in Figure 57 and 58, the insulation course of being made by silicon oxide film 1002 is formed on the monocrystalline silicon infrabasal plate 1001.Four drive electrode 1003-1 to 1003-4 are set on the insulation course 1002 at infrabasal plate 1001 centers.Monocrystalline silicon pillar 1004 is set at the both sides of infrabasal plate 1001 upper surfaces.Distribution 1005-1 to 1005-4 is connected respectively to drive electrode 1003-1 to 1003-4, so that provide driving voltage from the power supply (not shown) to drive electrode 1003-1 to 1003-4.The drive electrode (not shown) of formed other mirror device on the same substrate 1001 and 1101 in distribution 1006 and the mirror device shown in Figure 57 and 58 is so that provide driving voltage to these drive electrodes.
Separately make the structure of the infrabasal plate 1001 shown in Figure 57 and 58 and the structure of upper substrate 1101.Upper substrate 1101 is welded on the pillar 1004, makes upper substrate 1101 join on the infrabasal plate 1001.In this mirror device, make catoptron 1103 ground connection.Apply plus or minus voltage to drive electrode 1003-1 to 1003-4, so that it is poor to produce asymmetric potential between drive electrode 1003-1 to 1003-4.Electrostatic force attracts catoptron 1103, and it is rotated in any direction.
As mentioned above, upper substrate 1101, gimbals 1102, catoptron 1103 and torsion spring 1104 and 1105 integral body are made by monocrystalline silicon.By upper substrate 1101, torsion spring 1104, gimbals 1102 and torsion spring 1105, apply predetermined potential (for example earth potential) to catoptron 1103.
Be disposed in position as the conductive component of the characteristic feature of present embodiment and catoptron 1103 equipotentiality than catoptron 1103 more close distribution 1005-1 to 1005-4 and 1006.This STRUCTURE DEPRESSION is because the anything unexpected variation at the caused catoptron of interference 1103 pitch angle of distribution 1005-1 to 1005-4 and 1006.In the present embodiment, monocrystalline silicon infrabasal plate (electrically-conductive backing plate) 1001 as and the conductive component of catoptron 1103 equipotentiality.That is, infrabasal plate 1001 and catoptron 1103 equipotentiality are shown in Figure 59.
For example be approximately 90 μ m apart from d between catoptron 1103 and the drive electrode 1003-1 to 1003-4.Because distribution 1005-1 to 1005-4 and 1006 and infrabasal plate 1001 between the thickness of insulation course 1002 less than distance d, so infrabasal plate 1001 is than catoptron 1103 more close distribution 1005-1 to 1005-4 and 1006.Therefore, when infrabasal plate 1001 and catoptron 1103 equipotentiality, all end at infrabasal plate 1001 those sides by apply most of line of electric force E that voltage V produced to distribution 1005-1, shown in Figure 59.This also is applicable to remaining distribution 1005-2 to 1005-4, though for convenience of description, Figure 59 has only shown the line of electric force of distribution 1005-1.According to present embodiment, might suppress because the anything unexpected at the caused catoptron of interference 1103 pitch angle of distribution 1005-1 to 1005-4 and 1006 changes.
When insulated substrate when the infrabasal plate, will end at the substrate of that side of catoptron from the line of electric force of distribution, cause the interference of catoptron stronger thus.Even utilize this insulated substrate, if the shielding distribution of catoptron equipotentiality is arranged near the distribution, also can obtain with present embodiment in the same effect.Yet the shielding distribution has consumed extra area, therefore can not keep the wide spacing between distribution and the catoptron.
As mentioned above,, can be arranged in position, suppress because the accident at the caused mirror tilt of the interference angle of distribution changes by the conductive component of handle and catoptron equipotentiality than the more close distribution of catoptron according to present embodiment.In the present embodiment, because needn't form distribution in the lower face side of infrabasal plate, thus can be when keeping easy manufacturing, the variation at inhibitory reflex mirror pitch angle.In the present embodiment, because infrabasal plate is used as and the conductive component of catoptron equipotentiality, so can obtain conductive component easily than the more close distribution of catoptron.
[the 17 embodiment]
Next seventeenth embodiment of the invention will be described.Represent same section among Figure 60 with Reference numeral identical in Figure 57 and 58.
With the same in the 16 embodiment, in the present embodiment, infrabasal plate 1001 is used as the conductive component with catoptron 1103 equipotentiality.In addition, be formed on the insulation course 1007 on distribution 1005-1 to 1005-4 and 1006 conductive layer 1008 also as and the conductive component of catoptron 1103 equipotentiality.
For making conductive layer 1008 and catoptron 1103 equipotentiality,, form contact hole 1009 by partly removing infrabasal plate 1001 lip-deep insulation courses 1002.This structure can just directly be connected to infrabasal plate 1001 with conductive layer 1008 through distribution without the road, so that conductive layer 1008 and catoptron 1103 equipotentiality.Therefore, guarantee easily and being electrically connected of the isolate conductive layers 1008 that is difficult to interconnect.
As mentioned above, according to present embodiment, be formed on the insulation course on the distribution conductive layer as and the conductive component of catoptron equipotentiality.This has strengthened the effect that suppresses owing to the unexpected variation in the caused mirror tilt of interference angle of distribution.
[the 18 embodiment]
Next eighteenth embodiment of the invention will be described.Represent same section among Figure 61 with Reference numeral identical in Figure 57 and 58.
With the same in the 16 embodiment, in the present embodiment, infrabasal plate 1001 is used as the conductive component with catoptron 1103 equipotentiality.In addition, be arranged between catoptron 1103 and distribution 1005-1 to 1005-4 and 1006 wall shape conductive component 1010 also as and the conductive component of catoptron 1103 equipotentiality.
With the same in the 17 embodiment,,, form contact hole 1011 by partly removing insulation course 1002 for making wall segment 1010 and catoptron 1103 equipotentiality.Infrabasal plate 1001 is formed on the contact hole 1011.This structure can make wall segment 1010 and catoptron 1103 equipotentiality easily.
As mentioned above, according to present embodiment, be arranged between catoptron and the distribution wall shape conductive component as and the conductive component of catoptron equipotentiality.This has strengthened the effect that suppresses owing to the unexpected variation in the caused mirror tilt of interference angle of distribution.
In the 16 to the 18 embodiment, the distance between increase catoptron 1103 and distribution 1005-1 to 1005-4 and 1006 can strengthen the effect of the 16 to the 18 embodiment.When the pitch angle of catoptron 1103 control accuracy be approximately total pitch angle 1/1000 the time, in identical or still less the number of degrees, distribution 1005-1 to 1005-4 and 1006 influence are permissible.When diameter is 10 * 10 catoptrons 1103 of for example 500 μ m during with the 1mm pitch arrangement, the precision at about 1/1000 total pitch angle is corresponding to the light-beam position precision of about 10 μ m.
[the 19 embodiment]
Next nineteenth embodiment of the invention will be described.
At first will the conventional mirror device be described with reference to Figure 62 and 63.Represent same composition element in Figure 62 and 63 with Reference numeral identical in Figure 107 and 108.
Separately make the structure of the infrabasal plate 8001 shown in Figure 62 and 63 and the structure of upper substrate 8101.Upper substrate 8101 is welded on the pillar 8004, makes upper substrate 8101 join on the infrabasal plate 8001.In this mirror device, make catoptron 8103 ground connection.8003-1 to 8003-4 applies positive voltage to drive electrode, so that produce asymmetric electric potential difference between drive electrode 8003-1 to 8003-4.Electrostatic force attracts catoptron 8103, and make its above arbitrarily to rotation.
In the mirror device shown in Figure 62 and 63, it is non-linear putting on the driving voltage V of drive electrode 8003-1 to 8003-4 and the relation between catoptron 8103 tiltangles.Especially, when tiltangle increased, tiltangle sharply increased with respect to the variation of driving voltage V.Finally, d θ/dV becomes infinity, produce a kind of be called as draw in or discharge, wherein drive electrode 8003-1 to 8003-4 attracts the non-steady state of catoptron 8103.When not applying driving voltage, draw in the angle and approximately be 1/3 of angle that catoptron 8103 and drive electrode 8003-1 to 8003-4 constituted.Figure 64 shows driving voltage to the characteristic example in pitch angle.With reference to Figure 64, θ p draws in the angle, and Vp is used to provide the pull-in voltage of drawing in angle θ p.
In the mirror device shown in Figure 62 and 63, torsion spring 8104 and 8105 supporting reflex mirrors 8103 are so that its random rotation.Torsion spring 8104 and 8105 is only showed low spring rate in the pivot direction in the ideal case, and shows infinitely great rigidity for all the other displacements.In fact, in order to obtain low spring rate in the pivot direction, the spring rate of vertical direction and expansion direction also must be low.Therefore, if by applying voltage to drive electrode 8003-1 to 8003-4, produce the moment that catoptron 8103 is rotated, then catoptron 8103 not only rotates, and near that side of drive electrode 8003-1 to 8003-4.
Under same drive voltage, rotate and do not move when its centre of gravity place is pivot center with catoptron 8103 and compare, when catoptron 8103 when that side of drive electrode 8003-1 to 8003-4 is sunk and is rotated, the tiltangle of catoptron 8103 is bigger.This is because the second power of distance increases between electrostatic force and catoptron 8103 and the drive electrode 8003-1 to 8003-4 inversely proportionally.If catoptron 8103 sinks, to compare with the situation that pivot center is fixing, catoptron 8103 tiltangles show bigger non-linear with respect to the increase of driving voltage.Driving voltage was to the characteristic example in pitch angle when Figure 65 showed catoptron 8103 sinkings and rotation.Family curve when the solid line among Figure 65 is represented catoptron 8103 sinkings and rotation.Family curve (family curve among Figure 64) when dotted line represents that catoptron 8103 does not sink.
As obviously finding out from Figure 65, when catoptron 8103 sank, tiltangle was non-linear more remarkable about driving voltage V's.Drawing in angle θ p and pull-in voltage Vp also reduces.Can prevent that the torsion spring structure that catoptron 8103 sinks from not having the problems referred to above.As mentioned above, in actual design, only be difficult to form at soft on the pivot direction of catoptron 8103 and hard torsion spring 8104 and 8105 on the sinking direction at catoptron 8103.
Proposed present embodiment for addressing the above problem, the purpose of present embodiment is to improve in the mirror device mirror tilt angle about the nonlinear response of driving voltage.
Below with reference to accompanying drawing embodiment of the present invention is described.Step teat 1305 is set at the center of monocrystalline silicon infrabasal plate 1301.Four drive electrode 1303-1 to 1303-4 be set at four angles of teat 1305 and the infrabasal plate 1301 that extends from these four angles on the insulation course 1302 made by silicon oxide film.Monocrystalline silicon pillar 1304 is set at the both sides of infrabasal plate 1301 upper surfaces.
Separately make the structure of the infrabasal plate 1301 shown in Figure 66 and 67 and the structure of upper substrate 1401.Upper substrate 1401 is welded on the pillar 1304, makes upper substrate 1401 join on the infrabasal plate 1301.In this mirror device, make catoptron 1403 ground connection.1303-1 to 1303-4 applies positive voltage to drive electrode, so that it is poor to produce asymmetric potential between drive electrode 1303-1 to 1303-4.Electrostatic force attracts catoptron 1403, and it is rotated in any direction.
In the present embodiment, sink, the pivot that is used for supporting reflex mirror 1403 pivot center (column) 1306 is formed on the upper surface of teat 1305 for preventing catoptron 1403.Be positioned at the pivot center of sharp column 1306 stationary mirrors 1403 of catoptron 1403 pivot center positions, prevent that catoptron 1403 from sinking, and allow catoptron 1403 to turn to the suitable angle of drawing in.
In the present embodiment, pivot 1306 prevents that catoptron 1403 from sinking.Therefore, torsion spring 1404 and 1405 spring rates in sinking direction (towards the downside of Figure 67) can be low.The spring rate of pivot direction (direction of arrow among Figure 67) also can be low.As a result, can be lower for making catoptron 1403 rotate required driving voltage than in the past.Infrabasal plate 1301, teat 1305 and pivot 1306 are made by monocrystalline silicon integratedly.For example, can or utilize RIE to form high-aspect-ratio structure, form pivot 1306 by the anisotropic silicon etching.
In the present embodiment, apply predetermined bias Vb from power supply 1501 to four drive electrode 1303-1 to 1303-4 that separate, shown in Figure 68.As before, upper substrate 1401, gimbals 1402, catoptron 1403 and torsion spring 1404 and 1405 are made by monocrystalline silicon integratedly.By upper substrate 1401, torsion spring 1404, gimbals 1402 and torsion spring 1405, apply earth potential to catoptron 1403.When only when drive electrode 1303-1 to 1303-4 applies bias voltage Vb, catoptron 1403 is kept equilibrium state (θ=0) and is not rotated.
To a kind of method that catoptron 1403 is rotated from this equilibrium state be described.At this, describe for convenient, the instruction book turning axle.The bispin rotating shaft will be described in the back.For catoptron 1403 is rotated around for example Y-axis, in drive electrode 1303-1 to 1303-4, apply Vb+Va near the drive electrode of catoptron 1403 (following will be called positive side drive electrode) 1303-1 and 1303-2, and to applying Vb+Vc, shown in Figure 69 away from the drive electrode of catoptron 1403 (following will be called the negative side drive electrode) 1303-3 and 1303-4.Make V equal to obtaining the required driving voltage of tiltangle of catoptron 1403.In this case and bias voltage Vb the voltage Va and the Vc that apply together be Va=V and Vc=-V.Bias voltage Vb and driving voltage V have the relation of V＜Vb.
In the present embodiment, when applying bias voltage Vb and when having produced electric potential difference under this state between positive side drive electrode and negative side drive electrode, catoptron 1403 can rotate, and tiltangle can improve about the linear response of driving voltage V.Figure 70 shows in the mirror device of present embodiment driving voltage to the characteristic example in pitch angle.According to present embodiment, from θ=0 to approaching to draw in angle θ
pThe relative broad range of angle in, can obtain almost linear response.If do not apply bias voltage Vb, then catoptron 1403 does not tilt basically, till applying high voltage, shown in Figure 64 and 65.Then, catoptron 1403 rotates suddenly, and arrives the state of drawing in.On the other hand, when applying bias voltage, in present embodiment, the electric potential difference between catoptron 1403 and positive side drive electrode and the negative side drive electrode is rotated pro rata.Therefore, can improve the rotation controllability of catoptron 1403.
Below will describe and to improve the reason of tiltangle by applying bias voltage Vb about the linear response of driving voltage.The tiltangle of catoptron 1403 increases according to putting on the voltage between catoptron 1403 and the drive electrode 1303-1 to 1303-4.Torsion spring 1404 that is produced by the rotating spring rigidity k of torsion spring 1404 and 1405 and 1405 recuperabilities and determined tiltangle from the balance between the electrostatic force of drive electrode 1303-1 to 1303-4.
Make M
SBe the recuperability moment of torsion spring 1404 and 1405, M
EBe electrostatic force moment.Moment M
SAnd M
EProvide by following formula
M
S＝-kθ …(2)
M
E＝M
E(V，θ) …(3)
Electrostatic force moment M
ETherefore the shape that depends on drive electrode 1303-1 to 1303-4 uses function M
E(V θ) represents.Rigidity k depends on the shape of torsion spring 1404 and 1405.
Describe for convenient, suppose that positive side drive electrode 1303a and negative side drive electrode 1303b are arranged on the inclined-plane that the pitch angle is θ a, these two inclined-planes are about the bi-directional symmetrical by the vertical line L of catoptron 1403 pivot center, shown in Figure 71.The edge of each of positive side drive electrode 1303a and negative side drive electrode 1303b all with vertical line L be separated by x1 and x2.Catoptron 1403 rotates around Y-axis (perpendicular to the drawing surface of Figure 71).Ignorance is around the rotating torque of X-axis.
Make that Vb is a bias voltage, V is a driving voltage.Apply voltage (Vb-V) to negative side drive electrode 1303b.To positive side drive electrode application voltage (Vb+V).At this moment, the electrostatic force moment M of self-driven electrode 1303a of origin and 1303b
EProvide by following formula
In formula (4), the moment of first the positive side drive electrode 1303a of expression in the right, and the moment of second expression in the right negative side drive electrode 1303b.Formula (4) can be rewritten as
Suppose θ/θ a＜＜1, formula (5) is approximately
First expression in the parenthesis of formula (6), moment M
EProportional with the first power of voltage V.Because θ＜θ a/3 and V＜Vb so second in the parenthesis of formula (6) has so little value, makes and compare with first, in the angular range of broad, can ignore for this second.Balance between the recuperability of electrostatic force moment and torsion spring 1404 and 1405 has determined the tiltangle of catoptron 1403.
Therefore, can obtain
M
S+M
E＝0 …(7)
By formula (2) and (6), can obtain
Formula (8) can be approximately
As obviously finding out from formula (9), when applying bias voltage Vb, the tiltangle of catoptron 1403 is response voltage V linearly.
Be used under the situation that does not apply bias voltage Vb of comparison electrostatic force moment M
EProvide by following formula
Formula (10) can be rewritten as
Suppose θ/θ a＜＜1, formula (11) is similar to.By approximate expression and formula (2) and (7), can obtain
As obviously finding out, when not applying bias voltage Vb, even also proportional with the second power of voltage V at the tiltangle of small angle range internal reflector 1403 from formula (12).
Bias voltage Vb has higher limit clearly.This is because when bias voltage Vb has predetermined value or bigger value, even at the state of θ=0 time catoptron 1403 also instability, and can not recover.This phenomenon hint, θ=0 o'clock torsion spring 1404 and 1405 recuperability moment and the differential value of electrostatic force moment sum equal 0 or bigger.That is, catoptron 1403 can not return to the state of θ=0 o'clock.Catoptron 1403 arbitrarily rotates on the direction that tiltangle increases.Therefore, obtain the condition of bias voltage Vb by following formula
That is, bias voltage Vb satisfies dM
S/ d θ＜k.In the electrode structure shown in Figure 71, can obtain
Therefore, can obtain
As mentioned above, apply bias voltage Vb and improved of the linear response of the tiltangle of catoptron 1403 about driving voltage V.Yet, applying bias voltage Vb hint to drive electrode, that side draught of drive electrode draws catoptron 1403.When having only torsion spring 1404 and 1405 supporting reflex mirrors 1403, catoptron 1403 sinks, and therefore can not expect to improve linear response.Under extreme case, only take place to draw in to drive electrode.On the contrary, in the present embodiment, pivot 1306 is arranged in catoptron 1403 pivot center positions, even so that prevent also that when applying bias voltage catoptron 1403 from sinking.Therefore, can improve the linear response of tiltangle about voltage V.
Even by applying in the process that bias voltage Vb carry out to drive, draw in the draw in angle of angle when also seldom never applying bias voltage Vb and change.Therefore, the driving method that applies bias voltage Vb to drive electrode can improve the linear response of tiltangle about voltage V, and does not reduce the optional gyration of catoptron 1403 or the load that increases power supply 1501.
Bispin rotating shaft driving method will be described at last.Shown in Figure 72, in the bispin rotating shaft, apply Vb+V1, Vb+V2, Vb+V3 and Vb+V4 to four drive electrode 1303-1,1303-2,1303-3 and 1303-4 that separate respectively.
For obtaining the required driving voltage V1 to V4 in any pitch angle of catoptron 1403,, calculate the electrostatic capacitance between catoptron 1403 and the drive electrode 1303-1 to 1303-4 according to the relation of the position between catoptron 1403 and the drive electrode 1303-1 to 1303-4.Electrostatic capacitance change under the small reflector pitch angle is calculated the electrostatic force under the pitch angle.Be worth by this and obtain electrostatic force moment.Balance between the recuperability of this moment and torsion spring 1404 and 1405 has determined the relation between driving voltage V1 to V4 and catoptron 1403 pitch angle.
For calculating the electrostatic capacitance between catoptron 1403 and the drive electrode 1303-1 to 1303-4, need to come analysis of Electromagnetic by the relation of the position between catoptron 1403 and the drive electrode 1303-1 to 1303-4 is used as boundary condition.Usually utilize Finite Element Method to carry out numerical analysis.For example, the numerical analysis of using Finite Element Method is disclosed in below with reference to document: M.Fischer et al., " Electrostatically deflectable polysiliconmicromirrows-dynamic behavior and comparison with the results fromFEM modeling with ANSYS ", Sensors and Actuators, Vol.A67, pp.89-95,1998; Or M.Urano et al., " Novel Fabrication Process and Structure of aLow-Voltage-Operation Micromirror Array for Optical MEMS Switches ", Technical digest of Electron Device Meeting (IEDM ' 03), 8-10, Dec.2003.
Table (storage unit) 1502 stored the X of the catoptron 1403 that obtains like this and the relation between Y direction pitch angle and the driving voltage V1 to V4 in advance.Control circuit (acquiring unit) 1503 obtains the driving voltage V1 to V4 corresponding with catoptron 1403 pitch angle of expecting and is worth from table 1502, and these values are arranged in the power supply 1501.Power supply 1501 puts on drive electrode 1303-1 to 1303-4 with set driving voltage V1 to V4 and predetermined bias Vb together.
Next the method that bias voltage Vb is set will be described.As mentioned above, when the drive electrode to mirror device applied a certain value or bigger voltage, a kind of non-steady state of drawing in or discharging that is called as will take place.For preventing this point, need restriction will put on the voltage of drive electrode, promptly be provided with by driving voltage V and the represented maximal value that is applied in voltage (following will being called is applied in voltage max) of bias voltage Vb sum.As already described above, the mirror tilt angle becomes with driving voltage value.Unless bias voltage Vb value suitably is set, otherwise the attitude displacement of catoptron is with limited, and the mirror tilt angle that can not obtain expecting.Therefore, in the present embodiment, the following bias voltage Vb that is provided with.
For example, in Figure 73, drive electrode 1303-1 and 1303-3 be about the X-axis symmetry, and drive electrode 1303-2 and 1303-4 are about the Y-axis symmetry.In this case, for catoptron 1403 (not shown) that are arranged in drive electrode 1303-1 to 1303-4 top are rotated around Y-axis, positive side drive electrode 1303-1 in drive electrode 1303-1 to 1303-4 applies Vb+Va, and applies Vb+Vc to negative side drive electrode 1303-3.Make Vy equal to obtaining the required driving voltage of tiltangle y of catoptron 1403.In this case and bias voltage Vb the voltage Va and the Vc that apply together be Va=Vy and Vc=-Vy.Similar, rotate around X-axis for making catoptron 1403, apply Vb+Vd to positive side drive electrode 1303-2, and apply Vb+Ve to negative side drive electrode 1303-4.Make Vx equal to obtaining the required driving voltage of tiltangle x of catoptron 1403.In this case, voltage Vd and Ve are Vd=Vx and Ve=-Vx.
Figure 74 shows, for the drive electrode shown in Figure 73, when being made as 140 volts and driving voltage Vx is made as 0 volt when changing driving voltage Vy, the measurement result of the tiltangle y of catoptron 1403 by being applied in voltage max.Solid line a among Figure 74 represents, driving voltage Vy when bias voltage Vb is 0 volt and the relation between the tiltangle y.And, solid line b to 1 expression, bias voltage Vb during with 10 volts step change driving voltage Vy and the relation between the tiltangle y.
Shown in Figure 74, when bias voltage Vb changed, tiltangle y also changed.Especially, when bias voltage Vb be approximately be applied in voltage max 1/2 the time, indicated as solid line i and h (Vb=70,80 volts), it is maximum that tiltangle y reaches.Therefore, in the present embodiment, bias voltage Vb is made as to approximate greatly is applied in 1/2 of voltage max.This can increase the pitch angle of catoptron 1403.
Table 1502 is stored the bias voltage Vb that is provided with so in advance.Control circuit 1503 obtains driving voltage V1 to V4 corresponding with catoptron 1403 pitch angle of expecting and bias voltage Vb value from table 1502, and these values are arranged in the power supply 1501.Power supply 1501 puts on drive electrode 1303-1 to 1303-4 with set driving voltage V1 to V4 and bias voltage Vb together.
Figure 74 has illustrated the relation between driving voltage Vy and the tiltangle y.This also is applicable to the relation between driving voltage Vy and the tiltangle y.When the bias value that puts on drive electrode be approximately be applied in voltage max 1/2 the time, not only shown in Figure 73, in the mirror device that two axles rotate, can increase the pitch angle, and mirror device that rotates around axle or translation mirror device in, also can increase the pitch angle.
As mentioned above,, might pass through on infrabasal plate, to form the pivot center of pivot, and apply identical bias, improve of the linear response of mirror tilt angle about driving voltage to a plurality of drive electrodes in the face of catoptron with the supporting reflex mirror according to present embodiment.
According to present embodiment, memory storage is stored the mirror tilt angle in advance and is put on relation between the driving voltage of drive electrode.Be retrieved as the driving voltage value of each drive electrode that obtains expecting that the mirror tilt angle is required from memory storage, decision will put on the voltage of each drive electrode separately thus.
According to present embodiment, when the bias voltage that puts on drive electrode be approximately the maximum voltage value that can put on drive electrode 1/2 the time, can increase the mirror tilt angle.
[the 20 embodiment]
Below twentieth embodiment of the invention will be described.The purpose of present embodiment is to obtain following state: obtain bigger mirror tilt angle by low voltage drive, and do not increase cost.
Show to Figure 75 major part mirror device as the reflection mirror array component units.In reflection mirror array, the mirror device shown in Figure 75 is arranged two-dimensionally with square pattern.Mirror device comprises mirror substrate 1500 with catoptron and the electrode base board 1530 with electrode.Mirror substrate 1500 and electrode base board 1530 parallel layouts.Figure 75 shows the surface of mirror substrate 1500 in the face of electrode base board 1530, promptly a kind of state that is different from the skeleton view of Figure 11.
The connecting portion 1501a and the 1501b that comprise torsion spring in a zigzag and be set in the notch of removable framework 1502 are connected to removable framework 1502 with base portion 1501.This structure can be rotated the removable framework 1502 that is connected to base portion 1501 around the turning axle (removable framework turning axle) by connecting portion 1501a and 1501b.The catoptron connecting portion 1502a and the 1502b that comprise torsion spring in a zigzag and be set in the notch of removable framework 1502 are connected to catoptron 1503 with removable framework 1502.This structure can be rotated the catoptron 1503 that is connected to removable framework 1502 around the turning axle (catoptron turning axle) by catoptron connecting portion 1502a and 1502b.In the structure shown in Figure 75, removable framework turning axle and catoptron turning axle are with right angle intersection.
For example, in the mirror device shown in Figure 75, make public electrode 1541 ground connection.Apply plus or minus voltage to drive electrode 1503a to 1503d, so that it is poor to produce asymmetric potential between them.Because the electrostatic force that is produced, catoptron 1503 are near public electrode 1541 those sides, and upward rotation in any direction.The power supply of mirror device outside applies plus or minus voltage.
The teat 1536 that is formed the stair shape with a plurality of steps has public electrode 1541.This allows to reduce the distance between public electrode 1541 and the drive electrode 1503a to 1503d, and does not sacrifice the tiltangle of catoptron 1503.Therefore, the mirror device shown in Figure 75 can obtain big catoptron 1503 and draw in angle and low voltage drive.Be equal to or greater than under the tiltangle of drawing in the angle, can not steady stability ground control catoptron 1503.Draw in the angle if tiltangle is equal to or greater than, then electrostatic force surpasses the recuperability of connecting portion, makes catoptron 1503 contact electrode substrates 1530 those sides.As mentioned above, the mirror device shown in Figure 75 allows easily to form public electrode 1541, though teat 1536 has big jump.Therefore, the pitch angle of teat 1536 can be easily greater than before.As a result, in the mirror device shown in Figure 75, the pitch angle of catoptron 1503 can greater than before.
By convention, for obtaining to draw in angle and low voltage drive greatly, teat 8320 is arranged on the electrode base board 8301, and electrode is formed on the inclined-plane of teat 8320, as shown in figure 11.On the other hand, distribution 8370 is formed on the base portion 8310 of electrode base board 8301.In the process of the pattern that forms electrode or distribution, the focusing lower limit of exposure sources is made as the distribution 8370 with pattern meticulousr than electrode, guarantee to be formed the precision of pattern thus.Yet the depth of field of exposure sources is limited, and the difference of elevation of teat 8320 must be limited to 50 to 70 μ m or littler.
Yet,, preferably make the difference of elevation of teat 8320 bigger, and more particularly, making this difference of elevation is 100 μ m or bigger for obtaining bigger angle and the low voltage drive more drawn in.Can have the special-purpose exposure sources of wide focusing range or each step is carried out multiexposure, multiple exposure by use, obtain this state.Yet special-purpose exposure sources costs an arm and a leg.The increase of numbers of steps has caused the increase of processing cost.Therefore, by convention by increasing into the above-mentioned configuration of original acquisition.
Mirror device according to present embodiment comprises: be formed on the public electrode on the electrode base board; Be arranged in electrode base board top rotationally, simultaneously in the face of the mirror structure of this public electrode; And be set at lip-deep a plurality of drive electrodes in the face of the mirror structure of this public electrode.For example, when public electrode ground connection, and when drive electrode applied plus or minus voltage, mirror structure was owing to the electrostatic force that is produced rotates.
In this mirror device, almost conical teat is formed on the electrode base board, and at least a portion of public electrode is formed on this teat.Mirror structure is arranged to and can rotates around the turning axle by the mirror structure center.These a plurality of drive electrodes can be about mirror structure center symmetry.This mirror device also comprises: be set at the flanged structure on the public electrode electrode base board on every side; And mirror substrate, mirror structure is pivotally connected to this mirror substrate.Mirror substrate is fixed on this flanged structure.Therefore, obtained following state: mirror structure is disposed in the electrode base board top, simultaneously in the face of public electrode.
As mentioned above, according to the present invention, drive electrode is disposed on the mirror structure.That side of electrode base board only need have integrally formed public electrode.Might form big jump in that side of electrode base board, because do not need to form meticulous pattern.Therefore, can in the low voltage drive process, increase the angle of rotation of catoptron, and not increase any cost.
Next the example of the method for mirror substrate 1500 shown in a kind of Figure 75 of manufacturing will be described.At first, shown in Figure 76 A, prepare the SOI substrate, this SOI substrate is made and thickness is approximately the buried insulating layer 1602 of 1 μ m having to have on silica-based 1601 of planar orientation (100) by monox, and thickness is the monocrystalline silicon layer (soi layer) 1603 of 10 μ m.Oxide layer 1604 is formed on the surface of soi layer 1603, and for example oxide layer 1605 is formed on silica-based 1601 the lower surface by thermal oxide.
Shown in Figure 76 B, metal level 1606 is formed on the oxide layer 1604.For example, form the aluminium film, form metal level 1606 thus by sputter or gas deposition.Shown in Figure 76 C, the Etching mask layer 1701 with photoresist pattern forming by known photoetching is formed on the metal level 1606.By Etching mask layer 1701 is used as mask, come etch metal layers 1606.Shown in Figure 76 D, when removing Etching mask layer 1701, drive electrode 1503a and 1503c are formed on the oxide layer 1604.Utilize well-known dry ecthing such as active-ion-etch, finish processing.Figure 76 C to 76L shows the cross section, and therefore drive electrode 1503b and the 1503d shown in Figure 75 be not described.
Shown in Figure 76 E, the Etching mask layer 1702 with photoresist pattern forming by known photoetching is formed on the metal level 1604 that comprises drive electrode 1503a and 1503c.By Etching mask layer 1702 is used as mask, come etch metal layers 1604.At this moment, carry out directional etch such as active-ion-etch, so that the surface of the soi layer 1603 of etched part exposes.Utilize this technology, form inorganic mask layer 1604a, shown in Figure 76 F with silicon oxide mask pattern.At this moment, the pattern being used to form the line of serving as the cutting guiding is arranged in the regional (not shown) of Etching mask layer 1702.
By utilizing ozone or oxygen plasma to carry out ashing, remove Etching mask layer 1702.Shown in Figure 76 G,, come etching soi layer 1603 by inorganic mask layer 1604a carried out dry ecthing as mask.Utilize this etching, form base portion 1501, removable framework 1502, catoptron (mirror structure) 1503, connecting portion (not shown) and catoptron connecting portion (not shown).That is, finished the basic structure of mirror substrate.Formed line pattern in the regional (not shown) of Etching mask layer 1702 also is transferred on the inorganic mask layer 1604a, is transferred to then on the soi layer 1603.Mirror structure can just be connected to base portion by removable framework.
Shown in Figure 76 H, resin is coated onto on the inorganic mask 1604a that comprises drive electrode 1503a and 1503c, to form resin molding 1711, the gap in gap between the pattern of this resin molding 1711 filling inorganic mask 1604a and the soi layer 1603 between the formed structure.Shown in Figure 76 I; resin molding 1711 is carried out etch-back; to form protective seam 1712; this protective seam 1712 exposes the surface of drive electrode 1503a and 1503c and inorganic mask layer 1604a, and the gap between the formed structure in gap between the pattern of filling inorganic mask layer 1604a and the soi layer 1603.
Shown in Figure 76 J, by drive electrode 1503a and 1503c are come etching inorganic mask layer 1604a as mask, and remove inorganic mask layer 1604a, make drive electrode 1503a and 1503c be positioned on the insulation course 1506 on the soi layer 1603.Not optionally to remove inorganic mask layer 1604a, but can be it as insulation course 1506.Then, shown in Figure 76 K, utilize, come oxide layer 1605 and silica-based 1601 are carried out etching, to form frame section 1504 by the formed mask pattern of known photoetching (framework forms mask pattern).Remove mask pattern.Then, shown in Figure 76 L, for example, make frame section 1504 be fixed on the base portion 1501 by insulation course 1505 by using the wet etching or the dry ecthing of alkaline solution, remove oxide layer 1605 and the buried insulating layer 1602 that is exposed in the frame section 1504.
After this, for example by gas deposition on catoptron 1503 surfaces with frame section 1504, form the reflectance coating of making by for example golden film.Carry out following steps: formed mirror substrate is joined on the electrode base board, to form mirror device; Encapsulate this mirror device, and fix it by the wafer welding; And with the encapsulation the terminal wire bond to the terminal of electrode base board.Then, for example, remove protective seam 1712,, make removable framework 1502 and catoptron 1503 rotatable thus so that between base portion 1501, removable framework 1502 and catoptron 1503, form the gap by using the ashing of oxygen plasma.Utilize above-mentioned welding, mirror substrate 1500 is fixed on the flanged structure set on the electrode base board 1,530 1531.Can between above-mentioned encapsulation step, remove protective seam 1712.
For example, even, increased the exterior mechanical vibration, also might suppress the damage of connecting portion when mirror substrate 1500 is written into and is fixed in the vapor deposition apparatus with in the technology that forms above-mentioned reflectance coating.Similar, mirror substrate is being joined on the electrode base board to form the step of mirror device, encapsulate this mirror device and fix its step by wafer welding, and with the terminal wire bond of encapsulation in the step of the terminal of electrode base board, also might suppress the damage of connecting portion.
Above-mentioned manufacture method only is an example.Another kind of manufacture method also can be used for forming the mirror substrate shown in Figure 75.For example, forming the drive electrode structure of formation such as catoptron and removable framework later on.Yet, can form drive electrode later at formation catoptron and removable framework.By mask pattern is carried out etching as mask, form drive electrode.Yet, the invention is not restricted to this.Can form drive electrode by so-called stripping technology (lift-off).
Next description is connected to the distribution of formed drive electrode 1503a to 1503d on the catoptron 1503.For example, shown in the schematic plan view of Figure 77, can utilize distribution 1803a to 1803d, drive electrode 1503a to 1503d is guided to base portion 1501 those sides by connecting portion 1501a and 1501b and catoptron connecting portion 1502a and 1502b.Drive electrode is about the center symmetry of catoptron (mirror structure) 1503.
Shown in the part enlarged perspective of Figure 78, on surface of catoptron connecting portion 1502a on the formed insulation course 1506 set distribution 1813b can be connected to drive electrode 1503b, and go up on another surface of catoptron connecting portion 1502a, and set distribution 1813a can be connected to drive electrode 1503a on formed insulation course 1516.Distribution 1813a is by running through the plug (not shown) of insulation course 1506, catoptron 1503 and insulation course 1516, and is connected to drive electrode 1503a.This also is applicable to drive electrode 1503c to 1503d.
Shown in the part enlarged perspective of Figure 79, on surface of catoptron connecting portion 1502b on the formed insulation course 1506 set distribution 1823b can be connected to drive electrode 1503b, and the insulation course 1516a on the distribution 1823b goes up set distribution 1823a and can be connected to drive electrode 1503a.This also is applicable to drive electrode 1503c and 1503d.
Shown in the schematic plan view of Figure 80, catoptron 1503 can have two the drive electrode 1833a and the 1833b that separate.Can utilize distribution 1843a and 1843b, drive electrode 1833a and 1833b are guided to base portion 1501 those sides by connecting portion 1501a and 1501b and catoptron connecting portion 1502a and 1502b.Drive electrode is about the center symmetry of catoptron (mirror structure) 1503.
Shown in the schematic plan view of Figure 81, catoptron 1503 can have two the drive electrode 1853a and the 1853b that separate.Removable framework 1502 can have two the drive electrode 1853c and the 1853d that separate.Can utilize distribution 1863a and 1863b, drive electrode 1853a and 1853b are guided to base portion 1501 those sides by connecting portion 1501a and 1501b and catoptron connecting portion 1502a and 1502b.Can utilize distribution 1863c and 1863d, drive electrode 1853c and 1853d are guided to base portion 1501 those sides by connecting portion 1501a and 1501b.
In the foregoing description, public electrode 1541 is disposed in the zone that covers teat 1536.Yet, the invention is not restricted to this.Needn't be the arrangement of electrodes that is patterned in electrode base board 1530 those sides.For example, can be the metal level that is connected to earth potential as public electrode, be arranged in the whole zone in the face of the electrode base board 1530 of mirror substrate 1500.This allows to omit the step to the public electrode patterning, and easier of low cost manufacturing mirror device.Electrode base board 1530 can have the dull and stereotyped public electrode that does not have teat 1536.
[the 21 embodiment]
Next 21st embodiment of the invention will be described.Present embodiment comes more easily to increase the interval between mirror substrate and the electrode base board in the following manner: mirror substrate is joined on the flanged structure, inserts the gap auxiliary layer simultaneously between them, make mirror substrate separate with electrode base board by this gap auxiliary layer and flanged structure.
Below with reference to Figure 82 and 83 configuration example according to the mirror device of present embodiment is described.Show to Figure 82 and 83 major parts mirror device as the reflection mirror array component units.In reflection mirror array, for example the mirror device shown in Figure 82 is arranged two-dimensionally with square pattern.A plurality of electrode base boards 2000 that this reflection mirror array comprises a plurality of mirror substrates 1900 with catoptron and has the electrode part.Mirror substrate 1900 and electrode base board 2000 parallel layouts.
The connecting portion 1911a and the 1901b that comprise torsion spring in a zigzag and be set in the notch of removable framework 1920 are connected to removable framework 1920 with base portion 1910.This structure can be rotated the removable framework 1920 that is connected to base portion 1910 around the turning axle (removable framework turning axle) by connecting portion 1911a and 1901b.The catoptron connecting portion 1921a and the 1921b that comprise torsion spring in a zigzag and be set in the notch of removable framework 1920 are connected to catoptron 1930 with removable framework 1920.This structure can be rotated the catoptron 1930 that is connected to removable framework 1920 around the turning axle (catoptron turning axle) by catoptron connecting portion 1921a and 1921b.Removable framework turning axle and catoptron turning axle are with right angle intersection.
Therefore, form the gap of expectation by flanged structure 2010 and gap auxiliary layer 2101.This enables to suppress their thickness.As a result, even for example there is gap auxiliary layer 2101, the jump on the mirror substrate 1900 is also not too big.Therefore, can accurately form fine pattern, as connecting portion 1911a and 1911b and catoptron connecting portion 1921a and 1921b.Flanged structure 2010 and gap auxiliary layer 2101 supporting reflex mirror substrate 1900 and electrode base boards 2000, make them be spaced from each other a preset distance simultaneously, form a gap thus between mirror substrate 1900 and electrode base board 2000, removable frame such as catoptron 1930 can move in this gap.Therefore, only need on electrode base board 2000, not have to form flanged structure 2010 in the zone of electrode.Only need position, arrange gap auxiliary layer 2101 according to the flanged structure 2010 that forms like this.
For increasing the difference of elevation of teat, increase the interval (gap) between mirror substrate and the electrode base board.By convention, be difficult to increase the gap.For example, in the prior art, shown in the cross-sectional view of Figure 13, formed gap between mirror substrate 8201 and the electrode base board 8301 by making electrode base board 8301 formed jut (flanged structure) 8360a and 8360b.As selection, shown in the cross-sectional view of Figure 86, the frame section 8241 of mirror substrate 8200 has formed the gap between mirror substrate 8200 and the electrode base board 8300.Shown in the cross-sectional view of Figure 87, the last formed support portion 8260 of the frame section 8210 (base portion) of reflection mirror array 800 can form the gap between mirror substrate 8200 and the electrode base board 8300.
Yet, in the structure of Figure 13, form electrode and distribution later at formation jut 8360a and 8360b.Therefore, jut 8360a and 8360b can not be too high.Generally, form electrode and distribution by photoetching.In having the zone of big jump, the coating and the exposure of photoresist are difficult to.For example, in normal photoetching, the jump that allows to form pattern is approximately 70 μ m.
In the structure shown in Figure 86, can form the frame section 8241 of SOI substrate by making thick silica-based portion.Yet, because the gap is approximately 100 to 200 μ m, so base portion is thinned to about 100 to 200 μ m.Yet this thin mirror substrate has low-down intensity, and breaks easily in the processing in catoptron formation step or installation steps.In the structure shown in Figure 87, support portion 8260 has produced big jump on the soi layer with catoptron 8230 and frame section 8210.If there is big jump, then be difficult to fine structure such as connecting portion are carried out patterning.
Reflection mirror component according to present embodiment has said structure.Because mirror substrate joins on the flanged structure via the gap auxiliary layer,, make that the interval between mirror substrate and the electrode base board can more easily increase so gap auxiliary layer and flanged structure separate mirror substrate and electrode base board.Electrode base board can have from base portion stretch out and in the face of catoptron, be formed almost conical teat.Can be formed on electrode on this teat.
Next a kind of example of making the method for mirror substrate included in the mirror device of present embodiment 1900 will be described.At first, shown in Figure 84 A, prepare the SOI substrate, this SOI substrate is made and thickness for example is approximately the insulation course 1950 of 1 μ m having to have on silica-based the 1940a of planar orientation (100) by monox, and thickness is the monocrystalline silicon layer (soi layer) 1901 of 10 μ m.Insulation course 1950 is buried insulating layers.Shown in Figure 84 B, on silica-based 1940a, form gap auxiliary layer 2101.For example, can be by in the formation zone of gap auxiliary layer 2101, optionally forming Seed Layer, and on this Seed Layer, form metal level by metallide, form gap auxiliary layer 2101.Gap auxiliary layer 2101 need be formed on the boundary in the zone corresponding with mirror device.
Shown in Figure 84 C, on soi layer 1901, form mask pattern 2102.By mask pattern 2102 is used as mask, come etching soi layer 1901.At this moment, carry out directional etch such as active-ion-etch, so that the surface of etched partial insulating layer 1950 exposes.Utilize this etching, form base portion 1910, removable framework 1920, catoptron (mirror structure) 1930, connecting portion (not shown) and catoptron connecting portion (not shown).That is, shown in Figure 84 D, the basic structure of mirror substrate has been finished.
After removing mask pattern 2102, on the lower surface of silica-based 1940a, form the mask pattern (not shown).This mask pattern is corresponding to a mirror portion of reflection mirror array, and all has the square aperture district for each catoptron.By using CF base gas and this mask pattern being used as mask, carry out dry ecthing, thus silica-based 1940a carried out etching, till insulation course 1950 exposes.This technology can be wet etching.
After this, remove mask pattern.For example can remove mask pattern by ashing or suitable etching.Shown in Figure 84 E, remove the insulation course 1950 that is exposed in the formed open region, to form frame section 1940.In Figure 84 A to 84E, after forming the gap auxiliary layer, form connecting portion and catoptron connecting portion.Yet, the invention is not restricted to this.Can after the accurate fine pattern that forms connecting portion and catoptron connecting portion, form the gap auxiliary layer.
Next another example of the method for mirror substrate 1900 included in the mirror device of making present embodiment will be described.At first, shown in Figure 85 A, prepare the SOI substrate, this SOI substrate is made and thickness for example is approximately the insulation course 1950 of 1 μ m having to have on silica-based the 1940a of planar orientation (100) by monox, and thickness is the monocrystalline silicon layer (soi layer) 1901 of 10 μ m.This with reference to being the same in the described manufacture method of figure 84A to 84E.
Shown in Figure 85 B, on soi layer 1901, form mask pattern 2111.By mask pattern 2111 is used as mask, come etching soi layer 1901.At this moment, carry out directional etch such as active-ion-etch, so that the surface of etched partial insulating layer 1950 exposes.Utilize this etching, form base portion 1910, removable framework 1920, catoptron (mirror structure) 1930, connecting portion (not shown) and catoptron connecting portion (not shown).That is, shown in Figure 85 C, the basic structure of mirror substrate has been finished.
After removing mask pattern 2111, shown in Figure 85 D, go up the gap auxiliary layer 2101a that formation is made by for example glass at base portion 1910 (soi layer 1901).For example by known anodic bonding, auxiliary layer 2101a joins on silica-based 1910 with the glass gap.
On the lower surface of silica-based 1940a, form mask pattern.This mask pattern is corresponding to a mirror portion of reflection mirror array, and all has the square aperture district for each catoptron.By using CF base gas and this mask pattern being used as mask, carry out dry ecthing, thus silica-based 1940a carried out etching, till insulation course 1950 exposes.This technology can be wet etching.
After this, remove mask pattern.For example can remove mask pattern by ashing or suitable etching.Shown in Figure 85 E, remove the insulation course 1950 that is exposed in the formed open region, to form frame section 1940.
[the 22 embodiment]
Next 22nd embodiment of the invention will be described.
The element of the conventional mirror device 8200 shown in Figure 11 to 13, and mirror substrate 8201 element (following will be called movable part) that especially comprise removable framework 8220, catoptron 8230, removable framework connecting portion 8211a and 8211b and catoptron connecting portion 8221a and 8221b, catoptron 8230 separates with adjacent component, so that can rotate around catoptron turning axle and removable framework turning axle.Therefore, outside impact to mirror device 8200 may cause the movable part bump adjacent component of mirror substrate 8201, and breaks.Therefore, the contiguous parts of the movable part of mirror substrate 8201 and these movable parts must have at interval, with the bump between the adjacent element under the situation that prevents from externally to impact.
Proposed present embodiment for addressing the above problem, the purpose of present embodiment provides a kind of mirror device and reflection mirror array with high impact-resistant power.
Describe present embodiment in detail below with reference to accompanying drawing.Be made as predetermined value according to the interval between the reflection mirror array of the present embodiment parts that the movable part of the mirror substrate of mirror device included in the reflection mirror array and these movable parts is contiguous.Represent to illustrate same composition element among Figure 88 of present embodiment with title identical in the mirror device shown in Figure 14 to 16B and Reference numeral, and will omit description of them as required.
Mirror device included in the reflection mirror array according to present embodiment is made as predetermined value with four in the mirror substrate 200 interval d1 to d4.
Zoomed-in view a as Figure 88 is clearly shown that, d1 is the interval between the arc limit of the limit of opening 210a of frame section 210 and removable framework 220 at interval.
Zoomed-in view b as Figure 88 is clearly shown that, d2 is the interval between the catoptron connecting portion 221b and the second notch 223b at interval, more particularly, be catoptron connecting portion 221b perpendicular to the end on the direction of catoptron turning axle, and the second notch 223b is adjacent to this end and is parallel to interval between the limit of catoptron turning axle.At interval d2 also comprises, the end of catoptron connecting portion 221b on the direction that is parallel to the catoptron turning axle, and the second notch 223b is adjacent to this end and perpendicular to the interval between the limit of catoptron turning axle.
D2 also comprises the interval between the catoptron connecting portion 221a and the second notch 223a, the interval between the removable framework connecting portion 211a and the first notch 222a, and the interval between the removable framework connecting portion 211b and the first notch 222b at interval.Their detailed content is as follows.
Time interval between the catoptron connecting portion 221a and the second notch 223a, catoptron connecting portion 221a is perpendicular to the end on the direction of catoptron turning axle, and the second notch 223a is adjacent to this end and is parallel to interval between the limit of catoptron turning axle.This interval also comprises, the end of catoptron connecting portion 221a on the direction that is parallel to the catoptron turning axle, and the second notch 223a is adjacent to this end and perpendicular to the interval between the limit of catoptron turning axle.
Time interval between the removable framework connecting portion 211a and the first notch 222a, removable framework connecting portion 211a is perpendicular to the end on the direction of removable framework turning axle, and the first notch 222a is adjacent to this end and is parallel to interval between the limit of removable framework turning axle.This interval also comprises, the end of removable framework connecting portion 211a on the direction that is parallel to removable framework turning axle, and the first notch 222a is adjacent to this end and perpendicular to the interval between the limit of removable framework turning axle.
Time interval between the removable framework connecting portion 211b and the first notch 222b, removable framework connecting portion 211b is perpendicular to the end on the direction of removable framework turning axle, and the first notch 222b is adjacent to this end and is parallel to interval between the limit of removable framework turning axle.This interval also comprises, the end of removable framework connecting portion 211b on the direction that is parallel to removable framework turning axle, and the first notch 222b is adjacent to this end and perpendicular to the interval between the limit of removable framework turning axle.
Zoomed-in view c as Figure 88 is clearly shown that, d3 is the interval between the limit of the limit of opening 220a of removable framework 220 and catoptron 230 at interval.
Zoomed-in view d as Figure 88 is clearly shown that, d4 is the interval between catoptron connecting portion 221a and the removable framework 220 at interval, more particularly, be catoptron connecting portion 221a at that side that is connected to catoptron 230a and the end that forms along the catoptron turning axle, and the second notch 223a of removable framework 220 be communicated to the interval between the limit of interconnecting part 224a of opening 220a.
At interval d4 also comprises removable framework 220 and as the interval between the catoptron connecting portion 221b of catoptron connecting portion 221a corresponding connection parts, more particularly, be catoptron connecting portion 221b at that side that is connected to catoptron 230b and the end that forms along the catoptron turning axle, and the second notch 223b of removable framework 220 be communicated to the interval between the limit of interconnecting part 224b of opening 220b.
D1 to d4 at interval is set in the following manner.
Make m[kg] for the quality of mirror device movable part, make G[m/s
2] for putting on the acceleration of movable part.Movable part receives the power that is provided by mG.Make that d is the displacement of movable part, and make k support the removable framework connecting portion 211a of movable part and the spring constant of 211b and catoptron connecting portion 221a and 221b.Relation between m, G, k and the d is provided by following formula
mG＝kd …(15)
By formula (15), come displacement calculating amount d by following formula
d＝mG/k …(16)
D1 to d4 is set as the value greater than the displacement d of formula (16) at interval.Even when applying acceleration G to the reflection mirror array according to present embodiment, this movable part that also prevents mirror substrate 200 contacts with the parts that this movable part is close to and breaks.
Can come arbitrarily to be provided with acceleration G value as required according to the expectation value of the impact resistance of the reflection mirror array that will give present embodiment.
The movable part of mirror device is indicated removable framework 220 and catoptron 230.Removable framework 220 has peristome, as opening 220a, the first notch 222a and the 222b and second notch 223a and the 223b.In order to prevent that more reliably mirror device from breaking, be not have to set quality under the supposition of perfection circle of opening at movable part.Make that r is the radius of removable framework 220, ρ is the density of material of removable framework 220 and catoptron 230, and h is the thickness of removable framework 220 and catoptron 230.At this moment, the quality m of movable part is by π r
2ρ h provides.
Shown in Figure 89, zigzag torsion spring included among removable framework connecting portion 211a and 211b and catoptron connecting portion 221a and the 221b moves on X and Y direction.For the spring constant k of removable framework connecting portion 211a and 211b and catoptron connecting portion 221a and 221b, must consider the spring constant k on the X-axis
xWith the spring constant k on the Y direction
yThe reflection mirror array of present embodiment adopts spring constant k
xAnd k
yIn one of minimum, and with in its substitution formula (16).Even when applying acceleration G to mirror device, this movable part that also prevents mirror substrate 200 more reliably contacts with the parts that this movable part is close to and breaks.Therefore, the reflection mirror array according to present embodiment has high impact properties.
In the present embodiment, this supports removable framework 230 to removable framework connecting portion 211a and 211b.This is to catoptron connecting portion 221a and 221b supporting reflex mirror 230.The spring constant k of formula (15) and (16) indicates this spring constant value or this spring constant value to catoptron connecting portion 221a and 221b to removable framework connecting portion 211a and 211b.
Can after preestablishing interval d1 to d4, calculate the spring constant of removable framework connecting portion 211a and 211b and catoptron connecting portion 221a and 221b.In this case and the quality m of mirror device movable part and the acceleration G that puts on movable part together, among the displacement d of the formula (17) that the preset value substitution of d1 to d4 is at interval rewritten by formula (15), calculate spring constant k thus.According to the spring constant k that is calculated, the shape and size of removable framework connecting portion 211a and 211b and catoptron connecting portion 221a and 221b are set like this, so that the spring constant k of removable framework connecting portion 211a and 211b and catoptron connecting portion 221a and 221b
xAnd k
yAll surpassing the spring constant k that calculates from formula (17) on the direction separately.This has prevented that also the movable part of mirror substrate 200 from contacting with the contiguous parts of this movable part.
k＝mG/d …(17)
That next will describe spring constant is provided with example in detail.
For example, the quality of supposing the mirror device movable part is 1.6 * 10
-8[kg], the acceleration that puts on mirror device is 100G, and d1 to d4 is 10[μ m at interval].Calculate spring constant k by following formula
(1.6×10
-8)×(100×9.81)/(10×10
-6)≈1.57
Therefore, the shape of removable framework connecting portion 211a and 211b and catoptron connecting portion 221a and 221b etc. is set like this, so that the spring constant of removable framework connecting portion 211a and 211b and catoptron connecting portion 221a and 221b surpasses 1.57, to allow preventing that the movable part of mirror substrate 200 from contacting with the parts of this movable part vicinity.
Next a kind of method of making according to the reflection mirror array of present embodiment will be described.
At first, make that side of SOI substrate with buried insulating layer 250 (first type surface: soi layer) stand known photoetching and as the etching of DEEP RIE, so that in monocrystalline silicon layer, form the groove of the shape that meets frame section 210, removable framework connecting portion 211a and 211b, removable framework 220, catoptron connecting portion 221a and 221b and catoptron 230.
At this moment, form groove like this, so that above-mentioned interval d1 to d4 is equal to or greater than the displacement d that is calculated according to formula (16).More particularly, for example calculate the quality m of the movable part that comprises removable framework 220 and catoptron 230 from the shape of groove.For example calculate the spring constant k of removable framework connecting portion 211a and 211b and catoptron connecting portion 221a and 221b from the shape of groove.Set the acceleration G that reflection mirror array should stand.To produce displacement d in these value substitution formulas (16), and form groove like this, so that d1 to 4 is equal to or greater than this displacement d at interval.
On the lower surface of SOI substrate, be formed on the resist pattern that has opening in the presumptive area corresponding with these grooves.By using for example SF
6Dry ecthing, come optionally to etch away silicon from the lower surface of SOI substrate.In this etching,, come on the lower surface of SOI substrate, to form opening and shaped as frame parts 240 by buried insulating layer 250 is used as etching stopping layer.Can come etching silicon by using for example wet etching of potassium hydroxide.
By using for example CF
4The dry ecthing of gas removes buried insulating layer 250 zones that are exposed to opening.Can utilize hydrofluorite to remove buried insulating layer 250.
On the other hand, form electrode base board 300 by for example silicon substrate.
At first, by the predetermined mask pattern of being made by silicon nitride film or silicon oxide film is used as mask and uses potassium hydroxide solution, come optionally etching silicon substrate.By repeating above-mentioned technology, form base portion 310, first to the 3rd step 321 to 323, pivot 330, outer fissure 350 and protuberance 360a and 360b.
Make the silicon substrate surface oxidation of etched side, to form silicon oxide film.
For example on silicon oxide film, form metal film, and come this metal film is carried out patterning, to form electrode 340a to 340d, lead-in wire 341a to 341d and distribution 370 by known photoetching and etching by gas deposition.
Utilize this technology, form electrode base board 300 with above-mentioned shape.
Then, mirror substrate 200 is joined on the electrode base board 300, have the reflection mirror array of mirror device with formation, this mirror device can come mobile mirror 230 by applying electric field to electrode 340a to 340d.
Even when applying acceleration G, the reflection mirror array of the Zhi Zaoing movable part that also prevents mirror substrate 200 contacts with mirror substrate 200 another element that this movable part is close to and breaks like this.Therefore, the reflection mirror array according to present embodiment has high impact properties.
In the present embodiment, removable framework connecting portion 211a and 211b are set in the removable framework 220 among the formed first notch 222a and 222b.Removable framework connecting portion 211a and 211b can be set in the frame section 210 in the formed notch.Next will be with reference to Figure 90, the interval between the contiguous parts of movable part and this movable part is in this case described.Represent same composition element among Figure 90 with title identical in the mirror substrate 200 shown in Figure 88 and Reference numeral, and will omit description of them as required.
In the mirror substrate shown in Figure 90 200, comprise torsion spring in a zigzag and be set at a pair of the 3rd notch 212a of frame section 210 and among the 212b this is connected to removable framework 220 to removable framework connecting portion 211a and 211b with frame section 210.This structure can be rotated removable framework 220 around passing through this turning axle to removable framework connecting portion 211a and 211b (removable framework turning axle).
In the reflection mirror array shown in Figure 90,5 interval d1 to d5 in the mirror substrate 200 are set as the value of being calculated greater than through type (16).
At interval the same in d 1 to d4 and the mirror substrate 200 shown in Figure 88, and will omit description of them as required.
Zoomed-in view b as Figure 90 is clearly shown that, d2 is the interval between the catoptron connecting portion 221b and the second notch 223b at interval, more particularly, be catoptron connecting portion 221b perpendicular to the end on the direction of catoptron turning axle, and the second notch 223b is adjacent to this end and is parallel to interval between the limit of catoptron turning axle.At interval d2 also comprises, the end of catoptron connecting portion 221b on the direction that is parallel to the catoptron turning axle, and the second notch 223b is adjacent to this end and perpendicular to the interval between the limit of catoptron turning axle.
D2 also comprises the interval between the catoptron connecting portion 221a and the second notch 223a, the interval between removable framework connecting portion 211a and the 3rd notch 212a, and the interval between removable framework connecting portion 211b and the 3rd notch 212b at interval.Their detailed content is as follows.
Time interval between the catoptron connecting portion 221a and the second notch 223a, catoptron connecting portion 221a is perpendicular to the end on the direction of catoptron turning axle, and the second notch 223a is adjacent to this end and is parallel to interval between the limit of catoptron turning axle.This interval also comprises, the end of catoptron connecting portion 221a on the direction that is parallel to the catoptron turning axle, and the second notch 223a is adjacent to this end and perpendicular to the interval between the limit of catoptron turning axle.
Time interval between removable framework connecting portion 211a and the 3rd notch 212a, removable framework connecting portion 211a is perpendicular to the end on the direction of removable framework turning axle, and the 3rd notch 212a is adjacent to this end and is parallel to interval between the limit of removable framework turning axle.This interval also comprises, the end of removable framework connecting portion 211a on the direction that is parallel to removable framework turning axle, and the 3rd notch 212a is adjacent to this end and perpendicular to the interval between the limit of removable framework turning axle.
Time interval between removable framework connecting portion 211b and the 3rd notch 212b, removable framework connecting portion 211b is perpendicular to the end on the direction of removable framework turning axle, and the 3rd notch 212b is adjacent to this end and is parallel to interval between the limit of removable framework turning axle.This interval also comprises, the end of removable framework connecting portion 211b on the direction that is parallel to removable framework turning axle, and the 3rd notch 212b is adjacent to this end and perpendicular to the interval between the limit of removable framework turning axle.
Zoomed-in view e as Figure 90 is clearly shown that, d5 is the interval between removable framework connecting portion 211a and the frame section 210 at interval, more particularly, be removable framework connecting portion 211a at that side that is connected to removable framework 220 and the end that forms along removable framework turning axle, and the 3rd notch 212a of frame section 210 be communicated to the interval between the limit of interconnecting part 213a of opening 210a.
Interval d5 also comprises as the removable framework connecting portion 211b of the corresponding connection parts of removable framework connecting portion 211a and the interval between the frame section 210, more particularly, be removable framework connecting portion 211b at that side that is connected to removable framework 220 and the end that forms along removable framework turning axle, and the 3rd notch 212b of frame section 210 be communicated to the interval between the limit of interconnecting part 213b of opening 210a.
Even in this reflection mirror array, d1 to d5 also is set as the displacement d value greater than formula (16) at interval.Even when applying acceleration G, this movable part that also prevents mirror substrate 200 contacts with the parts that this movable part is close to and breaks.
As mentioned above, according to present embodiment, make that m is a mirror quality, G is the acceleration that puts on mirror device or reflection mirror array, and k is the spring constant of elastomeric element, and the interval between the frame parts of catoptron and supporting reflex mirror is made as mG/k or bigger.Even when applying acceleration G to mirror device or reflection mirror array, this also prevents catoptron bump frame parts and breaks.Therefore, mirror device of the present invention and reflection mirror array have high impact properties.
[the 23 embodiment]
Below 23th embodiment of the invention will be described.
As the hardware technology that realizes extensive photoswitch, twin shaft rotation 3 dimension mems optical switches have been subjected to extensive attention.Figure 91 shows traditional photoswitch.With reference to Figure 91, Reference numeral 8511a represents the input optical fibre array; 8511b represents the output optical fibre array; 8512a represents input end collimator array; 8512b represents output terminal collimator array; 8513a represents the input end reflection mirror array; And 8513b represents the output end mirror array.Each of fiber array 8511a and 8511b all comprises many optical fiber of two-dimensional arrangement.Each of collimator array 8512a and 8512b all comprises a plurality of lenticules of two-dimensional arrangement.Each of reflection mirror array 8513a and 8513b all comprises a plurality of mirror device 8514a and the 8514b of two-dimensional arrangement.Arrow among Figure 91 is represented the direction of propagation of light beam.
The lenticule that is transfused to end collimator array 8512a at the light signal of the input port of input optical fibre array 8511a output is converted to light beam, be transfused to terminal reflector array 8513a and output end mirror array 8513b sequentially reflects, the lenticule that is output end collimator array 8512b is assembled, and is directed to the optical fiber of output optical fibre array 8511b.The catoptron of included each mirror device 8514a and 8514b can both rotate around two axles among reflection mirror array 8513a and the 8513b, so that reflect incident light on the desired orientation corresponding with the mirror tilt angle.Might any input optical fibre be connected to any output optical fibre by the mirror tilt angle of control input end reflection mirror array 8513a suitably and output end mirror array 8513b, and switching-over light path.
The tool characteristic of above-mentioned photoswitch is reflection mirror array 8513a and 8513b.Mirror device 8514a and 8514b included among reflection mirror array 8513a and the 8513b have the structure shown in Figure 107 and 108.
In the mirror device shown in Figure 107 and 108, catoptron 8103 does not have directional dependency about the tiltangle of electrostatic force moment.If torsion spring 8104 and 8105 has same structure, and electrostatic force moment is identical, then catoptron 8103 is showed identical behavior, and is to rotate irrelevant around X-axis or Y-axis with it.Even in the rotatablely moving on any direction between X-axis and Y-axis, under identical moment, catoptron 8103 is also showed identical tiltangle.
Yet, be arranged in the face of catoptron 8103 to provide the drive electrode 8003-1 to 8003-4 that is used to control the electrostatic force that catoptron 8103 twin shafts rotatablely move, normally be formed four electrodes that separate.In addition, supply voltage normally has the upper limit, and the tiltangle of catoptron 8103 is because these are former thereby have a directional dependency.Control rotatablely moving of catoptron 8103 because put on the driving voltage of drive electrode 8003-1 to 8003-4, so in the little scope of tiltangle, the anisotropy of catoptron 8103 tiltangles does not throw into question.When supply voltage limited, and when catoptron 8103 can only turn to a certain limited tiltangle, catoptron 8103 be parallel to four separately the direction (X among Figure 107 and Y direction) of the cut-off rule of drive electrode 8003-1 to 8003-4 go up rotate in, the tiltangle of catoptron 8103 is big, and when catoptron 8103 rotated on the direction about these cut-off rule angles at 45, the tiltangle of catoptron 8103 was little.This be because, on the direction that is parallel to drive electrode 8003-1 to 8003-4 cut-off rule, two drive electrodes can attract catoptron 8103 by electrostatic force, and on the direction about these cut-off rule angles at 45, have only a drive electrode need attract catoptron 8103.
Therefore, shown in Figure 92, when reflection mirror array 8513a faces as among Figure 91 mutually with 8513b, zone (receiving catoptrical zone) 301 on the output end mirror array 8513b that can scan from catoptron 8103 by the catoptron 8103 of the input end mirror device 8514a that arranged among the reflection mirror array 8513a, not on the direction of the cut-off rule of the drive electrode 8003-1 to 8003-4 that is parallel to input end mirror device 8514a, to narrow down, but on direction, narrow down about these cut-off rule angles at 45.This also is applicable to the zone on the input end reflection mirror array 8513a that can scan by the catoptron 8103 of the output end mirror device 8514b that arranged among the reflection mirror array 8513b.
On the contrary, when catoptron 8103 is arranged in the rectangle region 8602 of output end mirror array 8513b, but the catoptron 8103 that is arranged in scanning area 8601 outsides also must work effectively.Therefore, must apply more high driving voltage to the drive electrode 8003-1 to 8003-4 of input end mirror device 8514a, so that the catoptron 8103 of input end mirror device 8514a tilts greatly.For increase is used to control the driving voltage of catoptron, need to change power specifications, and also need to strengthen distribution insulation characterisitic, improve the voltage breakdown of connecting portion and cable.This has increased technical difficulty, has caused expensive.
On the other hand, when catoptron 8103 was arranged in the rectangle region 303 of output end mirror array 8513b, the catoptron 8103 of input end mirror device 8514a needn't tilt greatly.Therefore, driving voltage can be low.Yet, but scanning area 8601 is in fact of no use, but because there is not catoptron 8103 to be arranged in the dash area of the scanning area 8601 shown in Figure 92.Because photoswitch needs a plurality of passages, so but, increase the number of the catoptron of being arranged 8103 as much as possible preferably by using scanning area 8601 effectively.
If drive electrode is divided into eight or 16 parts rather than four parts, and with the rotation direction of catoptron 8103 irrespectively to applying voltage with 1/2 of total drive electrode area corresponding drive electrode, then there is not anisotropy in the tiltangle of catoptron 8103.Yet, in reflection mirror array 8513a and 8513b, must control tens of simultaneously to hundreds of catoptrons 8103.This has caused strongly need be being that the drive electrode number that a catoptron 8103 is prepared reduces to required minimum number.For four drive electrodes that separate, each all has the reflection mirror array 8513a of 100 catoptrons 8103 and 8513b to need at least 400 distributions.The processing of these distributions is very difficult.When separately the number of drive electrode further increased, the distribution number reached infeasible rank, made to be very difficult to make.
As mentioned above, in traditional photoswitch, because the anisotropy of the tiltangle of mirror device 8514a that is arranged among reflection mirror array 8513a and the 8513b and the catoptron 8103 of 8514b, the feasible driving voltage that puts on the drive electrode 8003-1 to 8003-4 of mirror device 8514a and 8514b must be high.If arrange that by reducing catoptron the district reduces driving voltage, then can not arrange catoptron efficiently.In addition, if reduce driving voltage by the number of cutting apart that increases drive electrode, then mirror device is difficult to make.
Proposed this and execute example for addressing the above problem, the purpose of present embodiment is to arrange catoptron efficiently in a pair of reflection mirror array set in photoswitch, prevents any increase of driving voltage and manufacture difficulty simultaneously.
Next will photoswitch according to present embodiment be described with reference to Figure 93.With reference to Figure 93, Reference numeral 2201a represents the input optical fibre array; 2201b represents the output optical fibre array; 2202a represents input end collimator array; 2202b represents output terminal collimator array; 2203a represents the input end reflection mirror array; And 2203b represents the output end mirror array.Each of fiber array 2201a and 2201b all comprises many optical fiber of two-dimensional arrangement.Each of collimator array 2202a and 2202b all comprises a plurality of lenticules of two-dimensional arrangement.Each of reflection mirror array 2203a and 2203b all comprises a plurality of mirror device 2214a and the 2214b of two-dimensional arrangement.Arrow among Figure 93 is represented the direction of propagation of light beam.
The lenticule of the optical fiber of input optical fibre array 2201a and input end collimator array 2202a forms with matrix and is arranged among the rectangle region 2204a.Mirror device 2214a with matrix arrangement with the rectangle region 2205a of regional 2204a corresponding input end reflection mirror array 2203a in.Similar, the lenticule of the optical fiber of output optical fibre array 2201b and output terminal collimator array 2202b forms with matrix and is arranged among the rectangle region 2204b.Mirror device 2214b with matrix arrangement in the rectangle region 2205b of the output end mirror array 2203b corresponding with regional 2204b.
As before, the lenticule that is transfused to end collimator array 2202a at the light signal of the input port of input optical fibre array 2201a output is converted to light beam, be transfused to terminal reflector array 2203a and output end mirror array 2203b sequentially reflects, the lenticule that is output end collimator array 2202b is assembled, and is directed to the optical fiber of output optical fibre array 2201b.
Figure 94 shows according to the mirror device 2214a of present embodiment and the structure of 2214b.Represent same composition element among Figure 94 with title identical in the mirror device shown in Figure 1 and Reference numeral, and will omit description of them as required.
In the traditional photoswitch shown in Figure 91, wherein arranged a pair of opposite side of rectangle region 8515a of the reflection mirror array 8513a of mirror device 8514a, be parallel to first cut-off rule (for example X-direction) in the face of the drive electrode 8003-1 to 8003-4 of the mirror device 8514b of mirror device 8514a.In addition, another of rectangle region 8515a is parallel to second cut-off rule (for example Y direction) of the drive electrode 8003-1 to 8003-4 of mirror device 8514b to opposite side.Similar, wherein arranged a pair of opposite side of rectangle region 8515b of the reflection mirror array 8513b of mirror device 8514b, be parallel to first cut-off rule of the drive electrode 8003-1 to 8003-4 of mirror device 8514a.In addition, another of rectangle region 8515b is parallel to second cut-off rule of the drive electrode 8003-1 to 8003-4 of mirror device 8514a to opposite side.
In the present embodiment, wherein arranged a pair of opposite side (for example 2206 among Figure 95 and 2207) of rectangle region 2205b of the reflection mirror array 2203b of mirror device 2214b, intersected with 45 with in the face of first cut-off rule (for example X-direction) of the drive electrode 103-1 to 103-4 of the mirror device 2214a of mirror device 2214b.In addition, another of rectangle region 2205b intersects second cut-off rule (for example Y direction) of opposite side (for example 2208 among Figure 95 and 2209) with the drive electrode 103-1 to 103-4 of 45 and mirror device 2214a.
Similar, wherein arranged a pair of opposite side of rectangle region 2205a of the reflection mirror array 2203a of mirror device 2214a, intersect with 45 with in the face of first cut-off rule of the drive electrode 103-1 to 103-4 of the mirror device 2214b of mirror device 2214a.In addition, another of rectangle region 2205a intersects second cut-off rule of opposite side with the drive electrode 103-1 to 103-4 of 45 and mirror device 2214b.
The catoptron method for arranging indication of present embodiment, layout district 2205a and the 2205b of mirror device 2214a and 2214b are wide on the direction that is parallel to X and Y-axis, and narrow on the direction about X and Y-axis angle at 45.Promptly, in the present embodiment, the layout district 2205a of mirror device 2214a and 2214b and 2205b have and regional 8603 area identical shown in Figure 92 on the direction about X and Y-axis angle at 45, and extend to the dash area in zone 8601 on the direction that is parallel to X and Y-axis.But zone 8601 is scanning areas of the catoptron 153 of mirror device 2214a and 2214b.Therefore, needn't increase the maximum voltage that puts on drive electrode 103-1 to 103-4.
In the present embodiment, consider the anisotropy of the tiltangle of catoptron 153, optimize the layout of the catoptron 203 ( mirror device 2214a and 2214b) of reflection mirror array 2203a and 2203b.But this allows to use effectively the scanning area of catoptron 153, and obtains catoptron layout efficiently, and need not increase driving voltage.In the present embodiment, do not use a plurality of drive electrodes that separate, as eight or 16 drive electrodes that separate.Because only need change the cut-off rule direction of drive electrode 103-1 to 103-4, so can easily make reflection mirror array 2203a and 2203b as before.
As mentioned above, according to present embodiment, the anisotropy at the first mirror tilt angle that is determined according to cut-off rule direction by first drive electrode of first reflection mirror array, the catoptron that second reflection mirror array is set is arranged the district, and the anisotropy at the second mirror tilt angle that is determined according to the cut-off rule direction by second drive electrode of second reflection mirror array, the catoptron that first reflection mirror array is set is arranged the district.But this allows to use effectively the scanning area of first and second catoptrons, and obtains catoptron layout efficiently, and need not increase the driving voltage that puts on first and second drive electrodes.In the present invention, do not use a plurality of drive electrodes that separate, as eight or 16 drive electrodes that separate.Therefore, can easily make reflection mirror array 2203a and 2203b as before.
[the 24 embodiment]
In the 23 embodiment, consider the anisotropy of the tiltangle of catoptron 153, optimize the layout of the catoptron 153 of reflection mirror array 2203a and 2203b.As everyone knows, the drive electrode 103-1 to 103-4 with the stair shape shown in Figure 96 can reduce driving voltage.This is because can shorten the distance between drive electrode 103-1 to 103-4 and the catoptron 153 under the situation of the tiltangle of not sacrificing catoptron 153.In the mirror device shown in Figure 96, step teat 120 is formed on the center of infrabasal plate 101.Drive electrode 103-1 to 103-4 is set on the teat 120.
Ideally, shown in Figure 97, form the conical teat 120 of summit in catoptron 153 centers.On the inclined-plane of teat 120, form drive electrode 103-1 to 103-4 and allow to obtain to draw in greatly angle and low voltage drive.Be equal to or greater than under the tiltangle of drawing in the angle, can not stablizing control catoptron 153 statically.Draw in the angle if tiltangle is equal to or greater than, then electrostatic force will make catoptron 153 near drive electrode 103-1 to 103-4 above the recuperability of torsion spring.When drive electrode 103-1 to 103-4 is formed on the conical teat 120, draw in the angle and be approximately, when not applying voltage by 1/3 of the angle that the inclined-plane constituted of catoptron 153 and teat 120.
Be difficult to form this conical structure.In fact, be similar to conical step teat, and on step teat 120, form drive electrode 103-1 to 103-4 by silicon being carried out anisotropic etching, forming.Anisotropic etching has utilized the following fact: silicon exceedingly changes with crystal orientation with respect to the rate of etch of KOH.Therefore, (100) plane of silicon exposes on the etching direction, and (111) plane has formed the inclined-plane of teat 120.The pitch angle on inclined-plane is 57.4 °.Divide several steps to carry out anisotropic etching in any pitch angle for approximate the acquisition, approach to expect the step teat 120 at pitch angle with formation.
When upside is watched, the upper surface shape of each step of teat 120 all is almost square, as 106 among Figure 98 and 107 indicated.Because it is square that upper surface 121 and 122 is almost, so the angle that is made of catoptron 153 and inclined-plane becomes with direction.More particularly, on direction (for example Z-direction among Figure 98) and another direction (for example W direction of principal axis among Figure 98), big by the angle that the inclined-plane constituted of catoptron 153 and teat 120 to opposite side perpendicular to upper surface 121 perpendicular to a pair of opposite side of the upper surface 121 of teat 120.Yet, on about the direction at Z and W axle angle at 45 (upper surface 121 and 122 diagonal), little by the angle that the inclined-plane constituted of catoptron 153 and teat 120.As a result, draw in the angle when catoptron 153 rotates on about the direction at Z and W axle angle at 45, draw in the angle when on Z and W direction of principal axis, rotating less than catoptron 153.Actual formation is also measured the sample with structure shown in Figure 96.About in the rotatablely moving on the direction at Z and W axle angle at 45, it is little by about 20% to draw in the angle.
If it is enough big to draw in the angle, then can not go wrong, make and can form light path at the arbitrary portion of reflection mirror array.Yet the increase of drawing in the angle has caused the increase at the pitch angle of teat 120, the i.e. increase of the difference of elevation between the step of teat 120.Be the difference of elevation between the step that increases teat 120, the degree of depth of anisotropic etching must be big.In addition, because drive electrode 103-1 to 103-4 is formed on the surface of structure, so be difficult to make with big difference of elevation.That is,, then make very difficulty if guarantee to draw in the angle by the shape of teat 120.In addition, for the angle is drawn in increase, driving voltage must be high.
In fact, need a kind of minimum required design of drawing in the angle that has.That is, this design must tolerate that drawing in the angle is the allowable angle of inclination of catoptron 153, has the directional dependency that depends on drive electrode 103-1 to 103-4 3D shape.Because this directional dependency, for example the zone on the output end mirror array that can scan by the catoptron 153 of input end reflection mirror array is wide on Z and W direction of principal axis, and narrow on the direction about Z and W axle angle at 45.
In the present embodiment, except that being configured to of the 23 embodiment, the cut-off rule of drive electrode 103-1 to 103-4 also is parallel to Z and W axle.For example, shown in Figure 99, be formed on the teat 120 and drive electrode 103-1 to 103-4 on every side has first cut-off rule (X-direction) that is parallel to the Z axle, and second cut-off rule (Y direction) that is parallel to the W axle.That is, drive electrode 103-1 to 103-4 be formed on four angles of teat 120 and the infrabasal plate 101 that extends from these four angles on.
But said structure can make the scanning area (301 among Figure 92) of the catoptron 153 that the cut-off rule direction by drive electrode 103-1 to 103-4 determined, but with the overlapped scope maximization of scanning area by the catoptron that 3D shape determined 153 of drive electrode 103-1 to 103-4.That is, but but can make final scanning area maximization by two kinds of catoptrons that scanning area determined 153.As a result, the layout district 2205a of reflection mirror array 2203a and 2203b and 2205b can have maximum area.
As mentioned above, according to present embodiment, in four drive electrodes on being formed on the step teat dividually, be set as first cut-off rule perpendicular to the direction of a pair of opposite side of this teat upper surface, wherein the upper surface when this step teat when upside is watched is almost square.Another direction to opposite side perpendicular to this teat upper surface is set as second cut-off rule.When forming electrode on four angles at teat under these conditions, the catoptron of first and second reflection mirror arrays arranges that can there be maximum area in the district.
[the 25 embodiment]
Next 25th embodiment of the invention will be described.
About traditional photoswitch as shown in figure 23, it is reported, the flatness of catoptron 8230 influences junction loss and (the Xiaoming Zhu and Joseph M.Kahn that crosstalks, ComputingInsertion Loss in MEMS Optical Switches Caused By Non-Flat Mirrors, CLEO2001 CtuM43, May 8,2001, pp.185-186).Therefore, the mirror substrate 8201 of conventional mirror device 8200 is as shown in figure 13 made by the monocrystalline silicon with excellent planar degree.Because silicon has high-transmission rate in the communication wavelengths band, so as mentioned above, the general for example metal level of gold that on the reflecting surface of catoptron 8230, forms.On catoptron 8230, form in the metal level process, add hot mirror 8230.If catoptron 8230 is under the room temperature, then metal level will cool off and shrink.This has produced internal stress between metal level and silicon, make catoptron 8230 bendings.Especially when the chromium layer further being set improving clinging power between silicon and the gold, internal stress increases, and makes crooked the increasing.By convention, need the bending of control catoptron 8230.
Not only will be by making catoptron 8230 flat, and to could form the low-loss optically switch by using the optical design of concave surface.Yet by convention, the amount of bow of catoptron 230 is difficult to control.
Proposed present embodiment for addressing the above problem, the purpose of present embodiment provides a kind of mirror device manufacture method that can make the catoptron with expectation amount of bow.
Next will present embodiment be described with reference to figure 100A to 100C.Comprise a plurality of mirror devices according to the reflection mirror array of present embodiment, and have characteristic feature on the mirror structure in mirror device with the matrix form two-dimensional arrangement.With identical title and Reference numeral in mirror device, reflection mirror array and the photoswitch described in reference Figure 11,12 and 29 " background technology ", same composition element in the reflection mirror array of expression present embodiment, and will omit description of them as required.
Amount of bow with catoptron 230 of said structure depends on the thickness of upper surface layer 232 and undersurface layer 233.Come this is described below with reference to Figure 101 A to 102C.In Figure 101 A and 101B, ordinate is represented the amount of bow of catoptron 230, and it is the radial distance of the catoptron 230 of 600 μ m that horizontal ordinate is represented diameter.Figure 101 A shows, the amount of bow of the lower face side of catoptron 230 when the thickness of the upper surface layer 232 that is made of gold is 0.23 μ m.Figure 101 B shows, the amount of bow of the lower face side of catoptron 230 when the thickness of the upper surface layer 232 that is made of gold is 0.15 μ m.Figure 101 A and 101B show the measurement result by being obtained from the three-dimensional surface structure analysis microscope " NewView200 " that Zygo obtains.
The bending indication of catoptron 230, flat catoptron 230 bendings, the radius-of-curvature of the catoptron 230 under the promptly infinite state has reduced.The amount of bow indication of catoptron 230, between plane mirror 230 and the curved reflectors 230 that on direction, bends perpendicular to catoptron 230 planes, poor based on catoptron 230 ends (the position reset on the ordinate among Figure 101 A and the 101B), shown in Figure 101.
Shown in Figure 101 A and 101B, along with the increase of upper surface layer 232 thickness, the amount of bow of catoptron 230 also increases.For example, shown in Figure 101 A, when the thickness of upper surface layer 232 was 0.23 μ m, the amount of bow maximum of catoptron 230 had surpassed 0.2 μ m.Shown in Figure 101 B, when the thickness of upper surface layer 232 was 0.15 μ m, the amount of bow maximum of catoptron 230 was less than 0.1 μ m on the other hand.Therefore, might control the amount of bow of catoptron 230 by the thickness of control upper surface layer 232 and undersurface layer 233.
For example, when upper surface layer 232 is formed when being thicker than undersurface layer 233, shown in Figure 102 A, can be formed on upper surface layer 232 those sides and have spill, promptly have a catoptron 230 of the concave surface that bends towards upper surface layer 232 those sides.On the contrary, when undersurface layer 233 is formed when being thicker than upper surface layer 232, shown in Figure 102 B, can be formed on undersurface layer 233 those sides and have spill, promptly have a catoptron 230 of the convex surface that bends towards undersurface layer 233 those sides.When upper surface layer 232 and undersurface layer 233 have much at one thickness, can form plane mirror 230.
Next will the method for a kind of manufacturing according to the reflection mirror array of present embodiment be described with reference to figure 103A to 103E.Present embodiment has characteristic feature on the mirror structure in the included mirror device in reflection mirror array.The same in the reflection mirror array described in electrode base board structure and the above embodiment.Therefore, with the description of omitting as required to the method for making electrode base board.
At first, shown in Figure 103 A, make that side of SOI substrate with buried insulating layer 250 (following will be called upper surface) stand known photoetching and as the etching of DEEP RIE, so that in monocrystalline silicon layer, form the groove of the shape that meets frame section 210, removable framework connecting portion 211a and 211b, removable framework 220, catoptron connecting portion 221a and 221b and catoptron 230.
Shown in Figure 103 B, on the lower surface of SOI substrate, be formed on the resist pattern that has opening in the presumptive area corresponding with these grooves.Utilize etchant such as potassium hydroxide solution, optionally etch away silicon from the lower surface of SOI substrate.In this etching,, come on the lower surface of SOI substrate, to form opening and shaped as frame parts 240 by buried insulating layer 250 is used as etching stopping layer.
Shown in Figure 103 C, utilize hydrofluorite to remove to be exposed to buried insulating layer 250 zones of this opening.
Shown in Figure 103 D, on the upper surface of SOI substrate, be formed on the mask that has opening in the presumptive area corresponding with catoptron 230.Sequentially form middle layer 232b and metal level 232a by known gas deposition or sputtering method, to form upper surface layer 232.At this moment, 232a forms any thickness with metal level, so that catoptron 230 has the amount of bow of expectation, i.e. Qi Wang radius-of-curvature.
Shown in Figure 103 E, on the lower surface of SOI substrate, be formed on the mask that has opening in the presumptive area corresponding with catoptron 230.Sequentially form middle layer 233b and metal level 233a by known gas deposition or sputtering method, to form undersurface layer 233.At this moment, 233a forms any thickness with metal level, so that catoptron 230 has the amount of bow of expectation, i.e. Qi Wang radius-of-curvature.
Measure the radius-of-curvature of catoptron 230.If measured radius-of-curvature is different from the radius-of-curvature of expectation, then according to with reference to figure 103D and the described identical program of 103E, come on catoptron 230, further to form metal level 232a and 233a one of at least according to the difference of radius-of-curvature.Utilize this technology, form catoptron 230 with intended shape.
As mentioned above, according to present embodiment,, control the amount of bow of catoptron 230 by control upper surface layer 232 and undersurface layer 233 thickness one of at least.This allows to make the catoptron 230 with desired curvature radius.
In the present embodiment, after forming upper surface layer 232 and undersurface layer 233, perhaps after joining to the mirror substrate 200 with upper surface layer 232 and undersurface layer 233 on the electrode base board 300, can be by heating mirror substrate 200, make mirror substrate 200 coolings then at leisure, realize annealing.The annealing temperature of this moment is equal to or higher than the higher temperature of the temperature in upper surface layer 232 and undersurface layer 233 forming processes.This permission is not producing under the situation of any influence the temperature variation in upper surface layer 232 and undersurface layer 233 forming processes, the shape of control catoptron 230.
[the 26 embodiment]
Next 26th embodiment of the invention will be described.Present embodiment is controlled the amount of bow of catoptron 230 by changing the temperature in upper surface layer 232 and undersurface layer 233 forming processes.Represent same composition element in the 26 embodiment with title identical in the 25 embodiment and Reference numeral, and will omit description of them as required.
The amount of bow of catoptron 230 also depends on the temperature in upper surface layer 232 and undersurface layer 233 forming processes.The difference of the temperature in room temperature and upper surface layer 232 and undersurface layer 233 forming processes becomes big more, and it is big more that the amount of bow of catoptron 230 just becomes.For example, when the temperature in upper surface layer 232 forming processes is higher than temperature in undersurface layer 233 forming processes, can form catoptron 230, shown in Figure 104 A with the concave surface that bends towards upper surface layer 232 those sides.On the contrary, when the temperature in undersurface layer 233 forming processes is higher than temperature in upper surface layer 232 forming processes, can form catoptron 230, shown in Figure 104 B with the convex surface that bends towards undersurface layer 233 those sides.When under temperature much at one, forming upper surface layer 232 and undersurface layer 233, can form plane mirror 230, shown in Figure 104 C.
Next will the method for a kind of manufacturing according to the reflection mirror array of present embodiment be described with reference to figure 103A to 103E.
At first, shown in Figure 103 A, make that side of SOI substrate with buried insulating layer 250 (following will be called upper surface) stand known photoetching and as the etching of DEEP RIE, so that in monocrystalline silicon layer, form the groove of the shape that meets frame section 210, removable framework connecting portion 211a and 211b, removable framework 220, catoptron connecting portion 221a and 221b and catoptron 230.
Shown in Figure 103 B, on the lower surface of SOI substrate, be formed on the resist pattern that has opening in the presumptive area corresponding with these grooves.Utilize etchant, optionally etch away silicon from the lower surface of SOI substrate as potassium hydroxide solution.In this etching,, come on the lower surface of SOI substrate, to form opening and shaped as frame parts 240 by buried insulating layer 250 is used as etching stopping layer.
Shown in Figure 103 C, utilize hydrofluorite to remove to be exposed to buried insulating layer 250 zones of this opening.
Then, should become concave surface, promptly should be crooked catoptron 230 surfaces on, form metal level.For example, for making upper surface layer 232 those lateral bending songs, on the upper surface of SOI substrate, be formed on the mask that has opening in the presumptive area corresponding, shown in Figure 103 D with catoptron 230.Sequentially form middle layer 232b and metal level 232a by known gas deposition or sputtering method, to form upper surface layer 232.At this moment, under first arbitrary temp, form metal level 232a, so that catoptron 230 has the amount of bow of expectation, i.e. Qi Wang radius-of-curvature.For example, the pedestal (susceptor) that is used for the SOI substrate is fixed on the equipment that is used to form metal level 232a has well heater.This well heater is heated to a certain arbitrary temp with the SOI substrate, and forms metal level 232a under this condition.First arbitrary temp is made as is higher than second arbitrary temp (will be described later).
On catoptron 230 surfaces that should become convex surface, form metal level.For example, in order to form convex surfaces, on the lower surface of SOI substrate, be formed on the mask that has opening in the presumptive area corresponding, shown in Figure 103 E with catoptron 230 in those sides of undersurface layer 233.Sequentially form middle layer 233b and metal level 233a by known gas deposition or sputtering method, to form undersurface layer 233.At this moment, under second arbitrary temp, form metal level 233a, so that catoptron 230 has the amount of bow of expectation, i.e. Qi Wang radius-of-curvature.For example, the pedestal (susceptor) that is used for the SOI substrate is fixed on the equipment that is used to form metal level 233a has well heater.This well heater is heated to a certain arbitrary temp with the SOI substrate, and forms metal level 233a under this condition.
Utilize this technology, form catoptron 230 with intended shape.As mentioned above, according to present embodiment,, control the amount of bow of catoptron 230 by the temperature in control upper surface layer 232 and undersurface layer 233 forming process one of at least.This allows to make the catoptron 230 with desired curvature radius.
In order to form plane mirror 230, second arbitrary temp is made as is higher than first arbitrary temp.Because each of upper surface layer 232 and undersurface layer 233 all is heated to second arbitrary temp, cool to room temperature then is so plane mirror 230 becomes straight.
In the present embodiment, with the same in the 25 embodiment, can control upper surface layer 232 and undersurface layer 233 thickness one of at least.This enables to control more accurately the shape of catoptron 230.
[the 27 embodiment]
Next 27th embodiment of the invention will be described.Present embodiment is controlled the amount of bow of catoptron 230 by the material of upper surface layer 232 and undersurface layer 233 is set according to thermal expansivity.Represent same composition element in the 27 embodiment with title identical in the 25 and 26 embodiments and Reference numeral, and will omit description of them as required.
The amount of bow of catoptron 230 also depends on the material coefficient of thermal expansion coefficient of upper surface layer 232 and undersurface layer 233.As mentioned above, when upper surface layer 232 that heats in forming process or undersurface layer 233 cool to room temperature and when shrinking, bending has taken place in catoptron 230.If the material coefficient of thermal expansion coefficient of upper surface layer 232 and undersurface layer 233 has changed, the amount of contraction when then cooling off also will change.Therefore, the amount of bow of catoptron 230 also will change.As mentioned above, present embodiment is controlled the amount of bow of catoptron 230 by the material of upper surface layer 232 and undersurface layer 233 is set according to thermal expansivity.
For example, when the material coefficient of thermal expansion coefficient of upper surface layer 232 during, can form catoptron 230, shown in Figure 104 A with the concave surface that bends towards upper surface layer 232 those sides greater than the material of undersurface layer 233.On the contrary, when the material coefficient of thermal expansion coefficient of undersurface layer 233 during, can form catoptron 230, shown in Figure 104 B with the convex surface that bends towards undersurface layer 233 those sides greater than the material of upper surface layer 232.When upper surface layer 232 and undersurface layer 233 are made by identical materials, can form plane mirror 230, shown in Figure 104 C.
Next will the method for a kind of manufacturing according to the reflection mirror array of present embodiment be described with reference to figure 103A to 103E.
At first, shown in Figure 103 A, make that side of SOI substrate with buried insulating layer 250 (following will be called upper surface) stand known photoetching and as the etching of DEEP RIE, so that in monocrystalline silicon layer, form the groove of the shape that meets frame section 210, removable framework connecting portion 211a and 211b, removable framework 220, catoptron connecting portion 221a and 221b and catoptron 230.
Shown in Figure 103 B, on the lower surface of SOI substrate, be formed on the resist pattern that has opening in the presumptive area corresponding with these grooves.Utilize etchant, optionally etch away silicon from the lower surface of SOI substrate as potassium hydroxide solution.In this etching,, come on the lower surface of SOI substrate, to form opening and shaped as frame parts 240 by buried insulating layer 250 is used as etching stopping layer.
Shown in Figure 103 C, utilize hydrofluorite to remove to be exposed to buried insulating layer 250 zones of this opening.
Shown in Figure 103 D, on the upper surface of SOI substrate, be formed on the mask that has opening in the presumptive area corresponding with catoptron 230.Sequentially form middle layer 232b and metal level 232a by known gas deposition or sputtering method, to form upper surface layer 232.At this moment, make metal level 232a, so that catoptron 230 has the amount of bow of expectation, i.e. Qi Wang radius-of-curvature by material with any thermal expansivity.
Shown in Figure 103 E, on the lower surface of SOI substrate, be formed on the mask that has opening in the presumptive area corresponding with catoptron 230.Sequentially form middle layer 233b and metal level 233a by known gas deposition or sputtering method, to form undersurface layer 233.At this moment, make metal level 233a, so that catoptron 230 has the amount of bow of expectation, i.e. Qi Wang radius-of-curvature by material with any thermal expansivity.Utilize this technology, form catoptron 230 with intended shape.
As mentioned above, according to present embodiment,, control the amount of bow of catoptron 230 by the material of upper surface layer 232 and undersurface layer 233 is set according to thermal expansivity.This allows to make the catoptron 230 with desired curvature radius.
In the present embodiment, after forming upper surface layer 232 and undersurface layer 233, perhaps after joining to the mirror substrate 200 with upper surface layer 232 and undersurface layer 233 on the electrode base board 300, can realize annealing by heating mirror substrate 200, making mirror substrate 200 coolings at leisure then.The annealing temperature of this moment is equal to or higher than the higher temperature of the temperature in upper surface layer 232 and undersurface layer 233 forming processes.This permission is not producing under the situation of any influence the temperature variation in upper surface layer 232 and undersurface layer 233 forming processes, the shape of control catoptron 230.
In the present embodiment, with the same in the 25 embodiment, also can control upper surface layer 232 and undersurface layer 233 thickness one of at least.This enables to control more accurately the shape of catoptron 230.
In the present embodiment, with the same in the 26 embodiment, also can control the temperature in upper surface layer 232 and undersurface layer 233 forming processes.This also enables to control more accurately the shape of catoptron 230.
In the 25 to the 27 embodiment,, control the amount of bow of catoptron 230 according to one of the thickness of metal level 232a and 233a, temperature in the forming process and thermal expansivity.Yet, can control the amount of bow of catoptron 230 according to all of these factors taken together.This enables to control more accurately the shape of catoptron 230.
In the 25 to the 27 embodiment, middle layer 232b and 233b are inserted between substrate layer 231 and metal level 232a and the 233a.Can omit middle layer 232b and 233b.
In the 25 to the 27 embodiment, after forming upper surface layer 232, form undersurface layer 233.Can put upside down the formation order.
Reflection mirror array and mirror device according to the 25 to the 27 embodiment not only can be used in the photoswitch, and can be used in measuring element, display and the scanner.
As mentioned above, according to the 25 to the 27 embodiment, might control the bending of catoptron by not only metal level also being set being provided with on a certain surface of catoptron on metal level but also another surface at catoptron.
[the 28 embodiment]
Next 28th embodiment of the invention will be described.
To method that make the conventional mirror device shown in Figure 11 and 12 be described briefly.Can form mirror substrate 8201 by the SOI substrate.This SOI substrate has thin silicone layer (soi layer) on the buried insulating layer on thick silica-based.Can form said structure such as base portion 8210, removable framework 8220 and catoptron 8230 by making soi layer.When staying frame shape, can form frame section 240 when the thick base portion of removing the SOI substrate.Insulation course 8241 shown in Figure 11 and 12 is corresponding to the buried insulating layer of SOI substrate.
Can utilize alkaline solution, the monocrystalline silicon substrate that has crystal orientation (100) on first type surface is carried out etching, form electrode base board 8301 thus as potassium hydroxide solution.Utilize monocrystalline silicon rate of etch ratio on (111) plane of alkali much lower on (100) and (110) plane.Can utilize this phenomenon, form and have teat 8320 and protuberance (flanged structure) 8360a and the 8360b that blocks Pyramid.
After forming the mirror portion that for example connects, when making catoptron remain rotatable state, handle the mirror substrate that forms in the above described manner by the catoptron connecting portion.For example, (substrate by spin coating rotates in the step that forms structure included in the catoptron by patterning or selective etch, board transport between the manufacturing equipment, and substrate cleans), the wafer cutting step, on mirror surface, form the step of metal level, mirror substrate joined to the step on the substrate with the electrode distribution that is used to drive catoptron, this structured wafer is welded as the step of encapsulation, the wire bond step, and in the sealing step, when keeping movable part, handle mirror substrate as the catoptron and removable framework that connect by frangible connecting portion.
In above-mentioned mirror device, provide attractive force by putting on the electric field that electrode produced that forms on the electrode base board to catoptron, and make the catoptron rotation several years.In order to control rotatablely move (position) of catoptron with high position precision, connecting portion is designed to be out of shape under small power.For example, connecting portion comprises that width is that 2 μ m and thickness are the torsion spring of 10 μ m.In case be subjected to energetically, connecting portion is fracture easily just.In case be subjected to energetically, the catoptron that is formed thinly self also ruptures easily or breaks.
In above-mentioned technology, current, make centrifugal force in the wafer exsiccation process, vibration or impact and to produce, and put on connecting portion and catoptron.Therefore, connecting portion ruptures easily, and perhaps catoptron breaks easily.As a result, the turnout of mirror substrate has reduced.Especially, if a catoptron defectiveness then comprises reflection mirror array with a plurality of mirror devices of the matrix arrangement defectiveness that also will become, caused the further reduction of output.
Proposed present embodiment for addressing the above problem, the purpose of present embodiment is with high zero defect unit output, forms mirror substrate.
Next will present embodiment be described with reference to figure 105A to 105K.At first, shown in Figure 105 A, prepare the SOI substrate, this SOI substrate is made and thickness is approximately the buried insulating layer 2302 of 1 μ m having to have on silica-based 2301 of planar orientation (100) by monox, and thickness is the monocrystalline silicon layer (soi layer) 2303 of 10 μ m.Oxide layer 2304 is formed on the surface of soi layer 2303, and by for example thermal oxide oxide layer 2305 is formed on silica-based 2301 the lower surface.
Shown in Figure 105 B, on oxide layer 2304, form the Etching mask layer 2306 that has by the formed photoresist pattern of known photoetching.By Etching mask layer 2306 is used as mask, come etching oxide layer 2304.At this moment, carry out directional etch such as active-ion-etch, so that the surface of the soi layer 2303 of etched part exposes.Utilize this technology, form inorganic mask layer (movable part formation mask pattern) 2304a, shown in Figure 105 C with silicon oxide mask pattern.At this moment, the pattern being used to form the line of serving as the cutting guiding is arranged in the regional (not shown) of Etching mask layer 2306.
By utilizing ozone or oxygen plasma to carry out ashing, remove Etching mask layer 2306.Shown in Figure 105 D,, come etching soi layer 2303 by inorganic mask 2304a is carried out dry ecthing as mask.Utilize this etching, form base portion 2301, removable framework 2303, catoptron (mirror structure) 2305, connecting portion (not shown) and catoptron connecting portion (not shown).That is, finished the basic structure of mirror substrate.Formed line pattern in the regional (not shown) of Etching mask layer 2306 also is transferred on the inorganic mask layer 2304a, is transferred to then on the soi layer 2303.Mirror structure can just be connected to base portion by removable framework.
As Figure 105 E, shown in resin is coated onto on the inorganic mask 2304a, forming resin molding 2307, this resin molding 2307 is filled the gap between the formed structure in gap between the pattern of inorganic mask 2304a and the soi layer 2303.Shown in Figure 105 F; resin molding 2307 is carried out etch-back; to form protective seam 2307a, this protective seam 2307a exposes the surface of inorganic mask layer 2304a, and the gap between the formed structure in gap between the pattern of filling inorganic mask layer 2304a and the soi layer 2303.
Shown in Figure 105 G, for example remove inorganic mask layer 2304a, form to fill in the soi layer 2303 with plane the protective seam 2307a in gap between the formed structure by known chemically mechanical polishing (CMP).As will be described, in that silica-based 2301 is carried out in the etched process, in each treatment facility, all repair the surface of soi layer 2303.Therefore, after removing inorganic mask layer 2304a, the surface of soi layer 2303 is preferably straight.
Then, shown in Figure 105 H, utilize, come oxide layer 2305 and silica-based 2301 are carried out etching, with formation frame section 2301a by the formed mask pattern of known photoetching (framework formation mask pattern).Remove this mask pattern.Then, shown in Figure 105 I, for example by using the wet etching or the dry ecthing of alkaline solution, remove oxide layer 2305 and the buried insulating layer 2302 that is exposed in the frame section 2301a.
Shown in Figure 105 J,, come on catoptron 2335 surfaces, to form for example metal film 2308 of gold with frame section 2301a for example by gas deposition.For example utilize die mask (stencil mask), on catoptron 2335 parts, optionally form metal film 2308.Carry out following steps: formed mirror substrate 2300 is joined on the electrode base board, to form mirror device; Encapsulate this mirror device, and fix it by the wafer welding; And with the encapsulation the terminal wire bond to the terminal of electrode base board.Then; for example, remove protective seam 2307a, so that between base portion 2301, removable framework 2302 and catoptron 2335, form the gap by using the ashing of oxygen plasma; make removable framework 2302 and catoptron 2335 rotatable thus, partly illustrate as Figure 105 K.Can after forming mirror device or between above-mentioned encapsulation step, remove protective seam 2307a.
Figure 106 is that diagram illustrates the skeleton view by the schematic construction of the formed mirror substrate 2300 of step described in Figure 105 A to 105I.Shown in Figure 106, mirror substrate 2300 comprises base portion 2301, removable framework 2303 and the catoptron 2335 that is formed in the soi layer 2303.Removable framework 2303 is disposed in the opening of base portion 2301, and is connected to base portion 2301 by a pair of connecting portion 2332a and 2332b.Catoptron 2335 is disposed in the opening of removable framework 2303, and is connected to removable framework 2303 by a pair of catoptron connecting portion 2334a and 2334b.Be formed on base portion 2301 frame section 2301a on every side and surround removable framework 2303 and catoptron 2335.Frame section 2301a is fixed on the base portion 2301 by buried insulating layer 2302.
The connecting portion 2332a and the 2332b that are set in the notch of removable framework 2303 are connected to removable framework 2303 with base portion 2301.The removable framework 2303 that is connected to base portion 2301 can rotate around the turning axle (removable framework turning axle) by connecting portion 2332a and 2332b.The catoptron connecting portion 2334a and the 2334b that are set in the notch of removable framework 2303 are connected to catoptron 2335 with removable framework 2303.The catoptron 2335 that is connected to removable framework 2303 can rotate around the catoptron turning axle by catoptron connecting portion 2334a and 2334b.
Said structure is identical with mirror substrate 8201 shown in Figure 11.Mirror substrate 2300 shown in Figure 106 comprises protective seam 2307a, and this protective seam 2307a fills the gap between base portion 2301, connecting portion 2332a and 2332b, removable framework 2303, catoptron connecting portion 2334a and 2334b and the catoptron 2335.Therefore, mirror substrate shown in Figure 106 2300 suppresses in the said structures such as the motion of rotating, thereby it is avoided because exterior mechanical vibrates and damages or break.
For example, though when be written into mirror substrate 2300 and be fixed in the vapor deposition apparatus, to form in the process with reference to the described metal film 2308 of figure 105J, increased the exterior mechanical vibration, also might suppress the damage of connecting portion.Similar, mirror substrate 2300 is being joined on the electrode base board to form the step of mirror device, encapsulate this mirror device and fix its step by wafer welding, and with the terminal wire bond of encapsulation in the step of the terminal of electrode base board, also might suppress the damage of connecting portion.
As mentioned above, according to present embodiment, when on buried insulating layer, forming base portion, connecting portion and mirror structure, formed the protective seam of filling gap between them.Even form buried insulating layer in the district, so that the two sides of silicon layer all exposes and when making mirror structure removable, can prevent that also mirror structure from moving when removing catoptron.As a result, according to the present invention, protection mirror structure and connecting portion are avoided damaging.This permission forms mirror substrate with high zero defect unit output.
The the 8th to the 28 embodiment can have the antistatic structure described in first to the 7th embodiment.
Industrial applicibility
The present invention can be applicable to: the static with speculum of angle of inclination may drives mirror device, Reflection mirror array with a plurality of mirror devices of two-dimensional arrangement has this reflection mirror array Photoswitch is made the method for mirror substrate included in this mirror device, and is made The method of this mirror device.
Claims (83)
1. a mirror device is characterized in that, comprising:
Being supported for can be with respect to the catoptron of mirror substrate rotation;
Be formed in the face of the drive electrode on the electrode base board of described mirror substrate; And
Be disposed in the antistatic structure in the gap between described catoptron and the described electrode base board,
Wherein, described drive electrode is controlled the pitch angle of described catoptron; Described mirror device further comprises the power supply that applies first electromotive force to described drive electrode, and described antistatic structure uses the metal material with described catoptron equipotentiality to cover the insulating material that is present in the gap, perhaps removes this insulating material; Described mirror device further comprises the first metal layer that is formed on as described antistatic structure in the face of on the described mirror surface of described drive electrode, and described power supply applies second electromotive force to described the first metal layer and described mirror substrate.
2. mirror device according to claim 1 is characterized in that described mirror substrate is electrically connected to described electrode base board.
3. mirror device according to claim 1 is characterized in that,
Described mirror substrate and described electrode base board with electric conductivity serve as described antistatic structure, and
Described power supply applies second electromotive force to described catoptron and described electrode base board.
4. mirror device according to claim 1 is characterized in that, forms the opening as described antistatic structure in the insulation course that covers described drive electrode.
5. mirror device according to claim 1 is characterized in that, further comprises second metal level around the described drive electrode that is formed on as described antistatic structure on the described electrode base board,
Wherein said power supply applies second electromotive force to described catoptron and described second metal level.
6. mirror device according to claim 5 is characterized in that, further comprises the distribution that described second metal level is connected to described power supply.
7. mirror device according to claim 6 is characterized in that described distribution is formed on the described electrode base board.
8. mirror device according to claim 6 is characterized in that, described distribution is formed between described electrode base board and described second metal level.
9. mirror device according to claim 1 is characterized in that,
Described electrode base board comprises:
Form by base portion with distribution, and in the face of the conical teat of the cardinal principle of described catoptron; And
Be formed on the groove in the described teat base portion on every side, and
Described drive electrode is formed on the surface of described teat and described groove at least, so that be electrically connected to described distribution.
10. mirror device according to claim 9 is characterized in that, described groove comprises:
Be formed on first groove in the described base portion; And
Be formed on second groove of described first channel bottom.
11. mirror device according to claim 9 is characterized in that, described groove comprises a plurality of grooves.
12. mirror device according to claim 1, it is characterized in that, described electrode base board further comprises: the fulcrum projection, described fulcrum raised face (RF) is to described catoptron, and is formed on the described electrode base board with the center of described catoptron and reaches different optional position, position on the described electrode base board.
13. mirror device according to claim 12 is characterized in that, further comprises from described electrode base board stretching out and having the teat on plane at upside,
Wherein said drive electrode is formed on the surface of described electrode base board and described teat, and
Described fulcrum projection is formed on the described plane.
14. mirror device according to claim 1 is characterized in that, further comprises described catoptron is connected to a pair of link on the described mirror substrate,
Described link has different spring constants.
15. mirror device according to claim 14 is characterized in that,
Described link comprises a pair of first link and a pair of second link, and
Described mirror substrate has first opening, and comprise removable framework, described removable framework is connected to described mirror substrate by described first link, so that be supported on rotationally in described first opening, and described removable framework has second opening, so that the described catoptron that connects by described second link, be supported on rotationally in described second opening.
16. mirror device according to claim 15 is characterized in that, described mirror substrate has notch, to hold described first link.
17. mirror device according to claim 15 is characterized in that, described removable framework has notch, to hold described first link.
18. mirror device according to claim 15 is characterized in that, described removable framework has notch, to hold described second link.
19. mirror device according to claim 1 is characterized in that, described drive electrode is formed on the described electrode base board, about the asymmetric optional position of the turning axle that reaches the described catoptron on the described electrode base board.
20. mirror device according to claim 19 is characterized in that, described drive electrode is parallel to the cut-off rule of described catoptron turning axle and divides.
21. mirror device according to claim 19 is characterized in that, further comprises the conical teat of cardinal principle that stretches out from described electrode base board,
Wherein said drive electrode is formed on the surface of described electrode base board and described teat.
22. mirror device according to claim 21 is characterized in that, described teat is formed on the described electrode base board, about the asymmetric optional position of the turning axle that reaches the described catoptron on the described electrode base board.
23. mirror device according to claim 1 is characterized in that, the turning axle of described catoptron is the center of gravity by described catoptron not.
24. mirror device according to claim 23 is characterized in that, further comprises a pair of link that described catoptron is connected to described mirror substrate.
25. mirror device according to claim 24 is characterized in that,
Described link comprises a pair of first link and a pair of second link, and
Described mirror substrate has first opening, and comprise removable framework, described removable framework is connected to described mirror substrate by described first link, so that be supported on rotationally in described first opening, and described removable framework has second opening, so that the described catoptron that connects by described second link, be supported on rotationally in described second opening.
26. mirror device according to claim 25 is characterized in that,
The turning axle of described catoptron comprises first turning axle by described a pair of first link, and second turning axle that passes through described a pair of second link, and
Described first turning axle and described second turning axle be the center of gravity by described catoptron not one of at least.
27. mirror device according to claim 25 is characterized in that, described mirror substrate has notch, to hold described first link.
28. mirror device according to claim 25 is characterized in that, described removable framework has notch, to hold described first link.
29. mirror device according to claim 1 is characterized in that, further comprises being connected to described drive electrode and being disposed on the described electrode base board, simultaneously the distribution that intersects with the turning axle of right angle and described catoptron.
30. mirror device according to claim 29 is characterized in that, further comprises:
Being supported for can be with respect to the annular gimbals of described mirror substrate rotation; And
Be connected to described drive electrode and be disposed on the described electrode base board, the distribution that intersects with the turning axle of right angle and described gimbals simultaneously,
Wherein said catoptron is set in the described gimbals, and is supported for and can rotates with respect to described gimbals.
31. mirror device according to claim 1 is characterized in that, further comprises:
Be formed on the described electrode base board so that the distribution of driving voltage is provided to described drive electrode; And
With described catoptron equipotentiality and be disposed in conductive component than the position of the more approaching described distribution of described catoptron.
32. mirror device according to claim 31 is characterized in that,
Described drive electrode and described distribution are formed on the insulation course on the described electrode base board with electric conductivity, and
Described electrode base board comprises the conductive component with described catoptron equipotentiality.
33. mirror device according to claim 32 is characterized in that, further comprises, as the conductive layer on the insulation course that is formed on the conductive component of described catoptron equipotentiality on the described distribution.
34. mirror device according to claim 32 is characterized in that, further comprise, as and the conductive component of described catoptron equipotentiality and be disposed in wall shape conductive component on the described electrode base board between described catoptron and the described distribution.
35. mirror device according to claim 1 is characterized in that, further comprises:
Be formed on the described electrode base board to support the pivot of described catoptron pivot center; And
Apply the control circuit of voltage to described drive electrode,
Wherein said drive electrode comprises a plurality of drive electrodes around the described pivot that is formed on the described electrode base board, and
Described control circuit is applied for separately to each drive electrode simultaneously and makes the required driving voltage of described catoptron rotation by applying single bias voltage to described a plurality of drive electrodes, controls the rotation of described catoptron.
36. mirror device according to claim 35 is characterized in that, described control circuit comprises:
Storage unit, described storage unit are stored the pitch angle of described catoptron in advance and are put on relation between the driving voltage of each drive electrode;
Acquiring unit, described acquiring unit and each drive electrode consistently are retrieved as the required driving voltage value in described mirror tilt angle that obtains expectation from described storage unit; And
Power supply, described power supply applies voltage separately to each drive electrode, and described voltage has with predetermined bias with for the corresponding value of driving voltage sum that each drive electrode obtained.
37. mirror device according to claim 35 is characterized in that, described bias voltage equal to put on described drive electrode maximum voltage value 1/2.
38. mirror device according to claim 1 is characterized in that, further comprises:
Control circuit, described control circuit apply one to described drive electrode simultaneously and control the rotating operation of described catoptron for making described catoptron rotate required driving voltage by applying bias voltage to described drive electrode,
Wherein said bias voltage equal to put on described drive electrode maximum voltage value 1/2.
39. according to the described mirror device of claim 38, it is characterized in that,
Described drive electrode comprises a plurality of drive electrodes that are formed on the described electrode base board, and
Described control circuit applies single bias voltage to described a plurality of drive electrodes.
40. according to the described mirror device of claim 38, it is characterized in that,
Described drive electrode comprises a pair of drive electrode about the asymmetric setting of turning axle of described catoptron, and
Described control circuit applies the voltage with value corresponding with described bias voltage and driving voltage sum to a drive electrode, and applies one to another drive electrode and have the value corresponding with the difference of described bias voltage and driving voltage.
41. mirror device according to claim 1 is characterized in that, further comprises a plurality of mirror electrodes that are set in the face of on the described mirror surface of described drive electrode.
42., it is characterized in that according to the described mirror device of claim 41, further comprise the conical teat of the cardinal principle that is formed on the described electrode base board,
At least a portion of wherein said drive electrode is formed on the described teat.
43. according to the described mirror device of claim 41, it is characterized in that,
Described catoptron is supported for and can rotates around the turning axle by described catoptron center, and
Described a plurality of mirror electrodes is arranged symmetrically about described catoptron center.
44., it is characterized in that according to the described mirror device of claim 41, further comprise the described drive electrode flanged structure on every side that is set on the described electrode base board,
Wherein said mirror substrate is fixed on the described flanged structure.
45. according to the described mirror substrate of claim 41, it is characterized in that, further comprise:
Described catoptron is connected to a pair of link of described mirror substrate; And
Connect described mirror electrodes one of at least and by described link a plurality of distributions one of at least.
46., it is characterized in that described distribution is formed at least one surface of described mirror substrate according to the described mirror device of claim 45.
47., it is characterized in that described distribution is stacked on the insulation course according to the described mirror device of claim 45.
48. according to the described mirror device of claim 45, it is characterized in that,
Described link comprises a pair of first link and a pair of second link, and
Described mirror substrate has first opening, and comprise removable framework, described removable framework is connected to described mirror substrate by described first link, so that be supported on rotationally in described first opening, and described removable framework has second opening, so that the described catoptron that connects by described second link, be supported on rotationally in described second opening.
49. mirror device according to claim 1 is characterized in that,
Described drive electrode is formed by the base portion of the described electrode base board with distribution, and face described catoptron simultaneously and be electrically connected to described distribution,
Described electrode base board comprises and is formed the flanged structure that the zone that forms described electrode is clipped in the middle, and
Described mirror substrate is formed by the silicon-on-insulator substrate, and described silicon-on-insulator substrate comprises the base portion part made by silicon, be formed on the buried insulating layer on the described base portion part and be formed on silicon layer on the described buried insulating layer,
Described mirror substrate comprises:
Base portion, described base portion have the catoptron that is formed on described silicon layer and form opening in the district, and are pivotally connected to the described catoptron in the opening of described base portion by a pair of connecting portion;
The catoptron that is formed on described base portion part and described embedding layer forms the opening in distinguishing; And
Be formed on the gap auxiliary layer on the described base portion of described silicon layer, and described mirror substrate joins described flanged structure to by described gap auxiliary layer.
50. according to the described mirror device of claim 49, it is characterized in that,
Described electrode base board further comprises the conical teat of the cardinal principle that is formed by described base portion and face described catoptron, and
Described drive electrode is formed on the described teat.
51. mirror device according to claim 1 is characterized in that, further comprises the elastomeric element that described catoptron is connected to described mirror substrate,
Wherein said mirror substrate has first opening,
Described catoptron is supported in described first opening rotationally by described elastomeric element, and
Make that m is the quality of described catoptron, G is the acceleration that puts on described mirror device, and k is the spring constant of described elastomeric element, and the interval between then described catoptron and the described elastomeric element is not less than mG/k.
52. according to the described mirror device of claim 51, it is characterized in that,
Described elastomeric element comprises a pair of first elastomeric element and a pair of second elastomeric element,
Described mirror substrate comprises removable framework, described removable framework is connected to described mirror substrate by described first elastomeric element, so that be supported on rotationally in described first opening, and described removable framework has second opening, so that the described catoptron that connects by described second elastomeric element is supported in described second opening rotationally, and
Make that m1 is the gross mass of described catoptron and described removable framework, G is the acceleration that puts on described mirror device, k1 is the spring constant of described first elastomeric element, and the interval between then described removable framework and the described mirror substrate is not less than m1G/k1.
53. according to the described mirror device of claim 51, it is characterized in that,
Described elastomeric element is disposed in the described mirror substrate in the formed notch, and
Interval between the limit of described notch and the described elastomeric element is not less than mG/k.
54. according to the described mirror device of claim 53, it is characterized in that,
Described elastomeric element comprises a pair of first elastomeric element and a pair of second elastomeric element,
Described mirror substrate comprises removable framework, described removable framework is connected to described mirror substrate by described first elastomeric element, so that be supported on rotationally in described first opening, and described removable framework has second opening, so that the described catoptron that connects by described second elastomeric element is supported in described second opening rotationally
Described first elastomeric element is disposed in the described mirror substrate in formed first notch, and
Make that m1 is the gross mass of described catoptron and described removable framework, G is the acceleration that puts on described mirror device, k1 is the spring constant of described first elastomeric element, and the interval between the limit of then described first notch and described first elastomeric element is not less than m1G/k1.
55. according to the described mirror device of claim 53, it is characterized in that,
Described elastomeric element comprises a pair of first elastomeric element and a pair of second elastomeric element,
Described mirror substrate comprises removable framework, described removable framework is connected to described mirror substrate by described first elastomeric element, so that be supported on rotationally in described first opening, and described removable framework has second opening, so that the described catoptron that connects by described second elastomeric element is supported in described second opening rotationally
Described first elastomeric element is disposed in the described removable framework in formed second notch, and
Make that m1 is the gross mass of described catoptron and described removable framework, G is the acceleration that puts on described mirror device, k1 is the spring constant of described first elastomeric element, and the interval between the limit of then described second notch and described first elastomeric element is not less than m1G/k1.
56. a reflection mirror array is characterized in that, has arranged a plurality of mirror devices two-dimensionally, each of described a plurality of mirror devices all comprises:
Being supported for can be with respect to the catoptron of mirror substrate rotation;
Be formed in the face of the drive electrode on the electrode base board of described mirror substrate; And
Be disposed in the antistatic structure in the gap between described catoptron and the described electrode base board,
Wherein, described drive electrode is controlled the pitch angle of described catoptron; Described mirror device further comprises the power supply that applies first electromotive force to described drive electrode, and described antistatic structure uses the metal material with described catoptron equipotentiality to cover the insulating material that is present in the gap, perhaps removes this insulating material; Described mirror device further comprises the first metal layer that is formed on as described antistatic structure in the face of on the described mirror surface of described drive electrode, and described power supply applies second electromotive force to described the first metal layer and described mirror substrate.
57. according to the described reflection mirror array of claim 56, it is characterized in that,
Described mirror device further comprises:
Being supported for can be with respect to the annular gimbals of described mirror substrate rotation; And
Be connected to described drive electrode and be disposed on the described electrode base board, the distribution that intersects with the turning axle of right angle and described gimbals simultaneously,
Described catoptron is set in the described gimbals, and is supported for and can rotates with respect to described gimbals,
When rectangular mirror being arranged that zoning is divided into four subregions by two diagonal line, described mirror device is arranged like this, so that in any two adjacent sectors that two intersection edges of being arranged the district by described catoptron and diagonal line are surrounded, the turning axle of described gimbals is all with right angle intersection, and
In each subregion, the distribution that is connected to described drive electrode all is arranged in perpendicular to the turning axle of described gimbals on the described electrode base board.
58. according to the described reflection mirror array of claim 56, it is characterized in that,
Described electrode base board further comprises the fulcrum projection, and described fulcrum raised face (RF) is to described catoptron, and is formed on the described electrode base board with described catoptron center and reaches different optional position, position on the described electrode base board, and
According to the position of the described mirror device in the described reflection mirror array, decide described optional position.
59. according to the described reflection mirror array of claim 56, it is characterized in that,
Described mirror device further comprises a pair of link that described catoptron is connected to described mirror substrate, and
According to the position of the described mirror device in the described reflection mirror array, decide the spring constant of described link.
60., it is characterized in that described link has different spring constants according to the described reflection mirror array of claim 59.
61. according to the described reflection mirror array of claim 56, it is characterized in that,
Described drive electrode is formed on the described electrode base board, about the asymmetric optional position of the turning axle that reaches the described catoptron on the described electrode base board, and
According to the position of the described mirror device in the described reflection mirror array, decide described optional position.
62. according to the described reflection mirror array of claim 56, it is characterized in that,
The turning axle of described catoptron is the center of gravity by described catoptron not, and
According to the position of the described mirror device in the described reflection mirror array, decide the bias between the center of gravity of the turning axle of described catoptron and described catoptron.
63. a photoswitch is characterized in that, comprising:
Reflection is from first reflection mirror array of the light of input port; And
Reflection is from the light of described first reflection mirror array and with second reflection mirror array of described photoconduction to output port,
Each of described first reflection mirror array and described second reflection mirror array all comprises:
The reflection mirror array that forms by a plurality of mirror devices of two-dimensional arrangement, each of described a plurality of mirror devices all comprise be supported for the catoptron that can rotate with respect to mirror substrate, be formed in the face of the drive electrode on the electrode base board of described mirror substrate and be disposed in described catoptron and described electrode base board between the gap in antistatic structure
Wherein, described drive electrode is controlled the pitch angle of described catoptron; Described mirror device further comprises the power supply that applies first electromotive force to described drive electrode, and described antistatic structure uses the metal material with described catoptron equipotentiality to cover the insulating material that is present in the gap, perhaps removes this insulating material; Described mirror device further comprises the first metal layer that is formed on as described antistatic structure in the face of on the described mirror surface of described drive electrode, and described power supply applies second electromotive force to described the first metal layer and described mirror substrate.
64. according to the described photoswitch of claim 63, it is characterized in that,
Described mirror device further comprises:
Being supported for can be with respect to the annular gimbals of described mirror substrate rotation; And
Be connected to described drive electrode and be disposed on the described electrode base board, the distribution that intersects with the turning axle of right angle and described gimbals simultaneously,
Described catoptron is set in the described gimbals, and is supported for and can rotates with respect to described gimbals,
When rectangular mirror being arranged that zoning is divided into four subregions by two diagonal line, described mirror device is arranged like this, so that in any two adjacent sectors that two intersection edges of being arranged the district by described catoptron and diagonal line are surrounded, the turning axle of described gimbals is all with right angle intersection, and
In each subregion, the distribution that is connected to described drive electrode all is arranged in perpendicular to the turning axle of described gimbals on the described electrode base board.
65. according to the described photoswitch of claim 63, it is characterized in that,
Described electrode base board further comprises the fulcrum projection, and described fulcrum raised face (RF) is to described catoptron, and is formed on the described electrode base board with described catoptron center and reaches different optional position, position on the described electrode base board, and
According to the position of the described mirror device in the described reflection mirror array, decide described optional position.
66. according to the described photoswitch of claim 63, it is characterized in that,
Described mirror device further comprises a pair of link that described catoptron is connected to described mirror substrate, and
According to the position of the described mirror device in the described reflection mirror array, decide the spring constant of described link.
67., it is characterized in that described link has different spring constants according to the described photoswitch of claim 66.
68. according to the described photoswitch of claim 63, it is characterized in that,
Described drive electrode is formed on the described electrode base board, about the asymmetric optional position of the turning axle that reaches the described catoptron on the described electrode base board, and
According to the position of the described mirror device in the described reflection mirror array, decide described optional position.
69. according to the described photoswitch of claim 63, it is characterized in that,
The turning axle of described catoptron is the center of gravity by described catoptron not, and
According to the position of the described mirror device in the described reflection mirror array, decide the bias between the center of gravity of the turning axle of described catoptron and described catoptron.
70. according to the described photoswitch of claim 63, it is characterized in that,
Described first reflection mirror array has a plurality of first catoptrons of two-dimensional arrangement, and establish for each of described a plurality of first catoptrons, in order to first drive electrode at the pitch angle of controlling described first catoptron,
Described second reflection mirror array has a plurality of second catoptrons of two-dimensional arrangement, and establish for each of described a plurality of second catoptrons, in order to second drive electrode at the pitch angle of controlling described second catoptron,
The anisotropy at the described second mirror tilt angle that is determined according to cut-off rule direction by described second drive electrode, the catoptron that described first reflection mirror array is set is arranged the district, and
The anisotropy at the described first mirror tilt angle that is determined according to the cut-off rule direction by described first drive electrode, the catoptron that described second reflection mirror array is set is arranged the district.
71. according to the described photoswitch of claim 70, it is characterized in that, each of described first drive electrode and described second drive electrode all comprises four spaced electrode that are formed on the step teat, described step teat is formed on the substrate, and when seeing, upside has square substantially upper surface, and
The rectangular mirror of described first reflection mirror array arranges that four limits distinguishing are crossing with 45 ° of cut-off rules with described second drive electrode, and the rectangular mirror of described second reflection mirror array arranges that four limits in district are crossing with 45 ° of cut-off rules with described first drive electrode.
72. according to the described photoswitch of claim 70, it is characterized in that, each of described first drive electrode and described second drive electrode all comprises four spaced electrode that are formed on the step teat, described step teat is formed on the substrate, and when seeing, upside has square substantially upper surface, the direction vertical with a pair of opposite side of the upper surface of described teat is set as first cut-off rule, and with another of the upper surface of described teat vertical direction of opposite side is set as second cut-off rule.
73. mirror device manufacture method, described mirror device comprises the mirror substrate with the plane mirror that supports rotationally, and in the face of described mirror substrate and having is used to control the electrode base board of the electrode that described catoptron rotates, described method is characterised in that and comprises:
First step prepares to have the mirror substrate of the plane mirror of support rotationally;
Second step forms the first metal layer on a surface of described catoptron;
Third step forms second metal level on another surface of described catoptron; And
The 4th step is placed on described mirror substrate on the described electrode base board, so that described electrode surface is to described catoptron.
74. according to the described mirror device manufacture method of claim 73, it is characterized in that,
In described second step, according to the shape of catoptron to be formed, the thickness of described the first metal layer is set, and
In described third step,, described second metal layer thickness is set according to the shape of catoptron to be formed.
75. according to the described mirror device manufacture method of claim 73, it is characterized in that,
In described second step, according to the shape of catoptron to be formed, the material of described the first metal layer is set, and
In described third step,, the material of described second metal level is set according to the shape of catoptron to be formed.
76. according to the described mirror device manufacture method of claim 73, it is characterized in that, further be included in the 5th step that described third step or the 4th step are annealed to described mirror substrate afterwards.
77. according to the described mirror device manufacture method of claim 73, it is characterized in that,
In described second step, according to the shape of catoptron to be formed, the temperature in the forming process of described the first metal layer is set, and
In described third step,, the temperature in the forming process of described second metal level is set according to the shape of catoptron to be formed.
78. a mirror device manufacture method, described mirror device comprise the mirror substrate with the catoptron that supports rotationally, and the electrode base board of facing described mirror substrate, described method is characterised in that and comprises:
First step is prepared described electrode base board, the conical teat of cardinal principle that described electrode base board has the plane, stretch out from described plane and be formed on groove the described plane around the described teat;
Second step on the surface of the described plane of described electrode base board and described teat and groove, forms metal level;
Third step carries out patterning to described metal level, and the focus with exposure sources is located on the described plane simultaneously, so that forming distribution on the described plane and on the surface of described at least teat and groove, and forms the electrode that is connected to described distribution; And
The 4th step is placed on described mirror substrate on the described electrode base board, so that described electrode surface is to described catoptron.
79. a mirror substrate manufacture method is characterized in that, comprises at least:
First step is prepared the silicon-on-insulator substrate, and described silicon-on-insulator substrate comprises buried insulating layer on baseplate part, the described baseplate part and the silicon layer on the described buried insulating layer;
Second step, on the surface of described silicon layer, form movable part and form mask pattern, and by this movable part formation mask pattern is carried out etching as mask, form described silicon layer, so that the catoptron on described buried insulating layer forms in the district, the tabular mirror structure that forms base portion and be connected to described base portion by a pair of connecting portion;
Third step forms the protective seam of filling the gap between described base portion, connecting portion and the mirror structure; And
The 4th step, on the surface of described baseplate part, form and have the framework formation mask pattern that forms district's corresponding opening with catoptron, and by this framework formation mask pattern is carried out etching as mask, remove described baseplate part and buried insulating layer, expose so that described catoptron forms the silicon layer of that side of baseplate part in the district, and form frame section in outside, described catoptron formation district.
80. according to the described mirror substrate manufacture method of claim 79, it is characterized in that, further be included in the 5th step that forms metal film on the mirror structure surface of formed that side of described frame section.
81. according to the described mirror substrate manufacture method of claim 79, it is characterized in that, further be included in and form the step of removing described protective seam behind the described frame section at least.
82. mirror device manufacture method, it is characterized in that, at least may further comprise the steps: the electrode base board that will have an electrode joins on the formed mirror substrate of mirror substrate manufacture method by claim 79, makes the mirror device of described electrode surface to mirror structure with formation
Wherein described mirror device is contained in the encapsulation and fixing, and with the terminal wire bond of described encapsulation to the terminal of described electrode base board.
83. 2 described mirror device manufacture methods is characterized in that according to Claim 8, further may further comprise the steps:
Before joining to described electrode base board on the described mirror substrate, on the mirror structure surface of formed that side of described frame section, form metal film; And
After joining to described electrode base board on the described mirror substrate, remove described protective seam.
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| JP000667/2005 | 2005-01-05 | ||
| JP2005000667 | 2005-01-05 | ||
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| JP005176/2005 | 2005-01-12 | ||
| JP005177/2005 | 2005-01-12 | ||
| JP005174/2005 | 2005-01-12 | ||
| JP010205/2005 | 2005-01-18 | ||
| JP014762/2005 | 2005-01-21 | ||
| JP014757/2005 | 2005-01-21 | ||
| JP013743/2005 | 2005-01-21 | ||
| JP014752/2005 | 2005-01-21 | ||
| JP016564/2005 | 2005-01-25 | ||
| JP016561/2005 | 2005-01-25 | ||
| JP016572/2005 | 2005-01-25 | ||
| JP055494/2005 | 2005-03-01 | ||
| JP072477/2005 | 2005-03-15 |
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