JP2001201709A - Manufacturing method of silicon vibration body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a manufacturing method of a silicon vibration body by which the cost is not high and which facilitates handling of a silicon substrate. SOLUTION: A mask pattern of a plane shape of a vibration part, a fixing part, and a beam part is formed at one surface of a first silicon wafer 10 thicker than a prescribed thickness of the vibration part, and one surface of the first silicon wafer 10 is etched more deeply than the prescribed thickness of the vibration part. A protective film is formed on both sides of a second silicon wafer 13, a mask pattern of a plane shape of a fixing part is formed by removing a part of the protective film of one surface, and etching one surface of the second silicon wafer 13 until it is penetrated, the protective film of another side surface of the second silicon wafer 13 is removed. The positioning of the first silicon wafer 10 and the second silicon wafer 13 is performed, they are joined so that each fixing part shape may coincide, and another surface side of the first silicon wafer 10 is ground to a thickness slighty thicker than the prescribed thickness of the vibration part. A specula finishing is made thereafter, and another surface side of the first mirror finished silicon wafer 10 is etched until the prescribed thickness of the vibration part is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a silicon vibrator made of single crystal silicon by applying micromachine technology.

[0002]

2. Description of the Related Art Single crystal silicon, of course, has excellent mechanical properties as well as its material properties. In addition, there is no such thing as metal fatigue due to long-term vibration unlike a metal material, and reliability can be ensured if a silicon vibrator is formed using silicon. From such a viewpoint, in recent years, as a micromachine technology, it has been attempted to fabricate a device by using a semiconductor manufacturing process to integrally form a vibrating portion, a fixed portion, and a beam portion supporting the vibrating portion on the fixed portion with single crystal silicon. ing.

Such a device includes a micromirror that vibrates the vibrating portion as an optical deflection mirror, an acceleration sensor that senses the degree of deformation of a beam portion that supports the vibrating portion (weight) that receives acceleration, and an acceleration sensor that detects the degree of acceleration. There are angular velocity sensors that sense Coriolis force that acts when applied, all of which utilize the excellent mechanical properties of silicon,
The vibrating part, the fixed part, and the beam part supporting the vibrating part on the fixed part are integrally formed of single crystal silicon. Among these devices, a method for manufacturing a micromirror will be described as a conventional example.

[0004] First, the configuration of the micro mirror will be described.
FIG. 20 is a perspective view of the micromirror. In the micromirror 50, a vibrating portion 52 having at least one surface serving as a mirror surface is disposed in an internal space of a fixing portion 51 of a rectangular frame body. , 53 via the fixing portion 51
It is supported swingably. When a vibration force is applied to the vibration unit 52 by a driving unit (not shown), the vibration unit 52
Due to the torsional deformation of No. 3, the beam vibrates around the beam portion 53 as an axis, and the vibration of the vibrating portion 52 changes the reflection angle of the light beam applied to the mirror surface and is optically polarized.

In order to vibrate the micromirror 50 at a high speed, the vibrating portion 52 and the beam portion 53 need to be made thin, and the fixed portion 51 has a rigidity that does not bend against vibration. It is necessary to make the thickness thicker.

FIGS. 21A to 21F show a first conventional example of a method for manufacturing a micromirror manufactured to satisfy such conditions. In FIG. 21A, a silicon substrate to be used includes a thick silicon layer 61 and a thin silicon layer 62.
The SOI wafer 60 has a SiO ₂ layer 63 interposed between the SOI wafer 60 and the thin silicon layer 62 having a predetermined thickness of the vibration part 52 and the beam part 53. SiO _{2 on} both sides of SOI wafer 60
(FIG. 21B), and the protective film 65 on the side of the thick silicon layer 61 is formed into a planar shape of the fixing portion 51 (the planar shape is a shape viewed from the planar side, that is, a planar shape). The mask pattern 66 having a planar shape of the fixing portion 51 is formed by removing the pattern in the shape of an arrow (the same applies hereinafter) (FIG. 21C). Next, etching is performed with an etching solution such as KOH or TMAH until the SiO ₂ layer 63 appears (FIG. 21D). At this time, SiO ₂ layer 63 becomes a stopper layer so not etched, SiO ₂
The etching stops when the surface of the layer 63 appears.
Next, the protection film 64 on the thin silicon layer 62 side is
1. By removing the vibrating part 52 and the pair of beam parts 53 while leaving the planar pattern, the fixed part 51 and the vibrating part 52 are removed.
Then, a planar mask pattern 67 of the pair of beam portions 53, 53 is formed (FIG. 21E). At this time, the mask pattern 67 is formed so as to be aligned with the planar mask pattern 66 of the fixing portion 51 on the opposite surface.
Then, etching is performed by using a technique such as reactive ion etching or chemical etching until a through hole is formed in the thin silicon layer 62, and the mask patterns 66 and 67 on both surfaces are removed, thereby completing the process (FIG. 21F).

FIGS. 1A to 1G show a method of manufacturing a micromirror according to a second conventional example. FIG. 22 (a), (d)
, The silicon substrates used are a thick silicon wafer 70 and a thin silicon wafer 71 of a single silicon layer, and the thin silicon wafer 71
Having a predetermined thickness. On both sides of the thick silicon wafer 70 to form a protective film 72 and 73 of SiO ₂ or the like (FIG. 22
(B)) By removing the protective film 72 on one surface while leaving the planar pattern of the fixing portion 51, a mask pattern 74 having the planar shape of the fixing portion 51 is formed.
Etching is performed to a predetermined depth with an etching solution such as AH (FIG. 22C).

Further, protective films 75 and 76 are formed on both surfaces of the thin silicon wafer 71 (FIG. 22E), and the thin silicon wafer 71 and the thick silicon wafer 70 are joined (FIG. 22F). Next, the protective films 75 and 76 on both sides of the thin silicon wafer 71 are removed while leaving the planar shape pattern of the fixed portion 51, the vibration portion 52 and the pair of beam portions 53 and 53, thereby removing the fixed portion 51 and the vibration portion. A mask pattern 77 having a planar shape of 52 and a pair of beams 53 is formed. At this time, the mask pattern 77 is formed while being aligned with the planar mask pattern 74 of the fixing portion of the thick silicon wafer 70. Then, etching is performed using a technique such as reactive ion etching or chemical etching until a through hole is formed in the thin silicon substrate 71 (FIG. 22).
(G)), the process is completed by removing the unnecessary mask pattern 77.

[0009]

However, in the case of the first conventional example, silicon (S) is used as a silicon substrate.
i) Since the SOI wafer 60, which is considerably more expensive than the wafer, is used, there is a problem that the silicon vibrator 50 becomes expensive. The thin silicon layer 62 is aligned with the mask pattern 66 of the fixed portion formed on the thick silicon layer 61.
Since the mask pattern 67 for the vibrating section 52, the beam section 53, and the like must be formed, there is a problem that special equipment such as a double-sided exposure machine is required. The need for this special equipment further increases the cost of the silicon vibrator 50. Also, since the lower part of the vibrating part 52 is an open space,
There is a problem that an electrode for electrostatic drive or the like cannot be provided, and a substrate provided with the electrode must be separately prepared and joined in order to perform the electrostatic drive or the like.

In the case of the second conventional example, inexpensive silicon (Si) wafers 70 and 71 are used as silicon substrates,
In addition, no special equipment such as a double-sided exposure machine is required for the alignment of the two mask patterns 74 and 77.
The cost does not increase, and an electrode can be provided below the vibrating body 52 instead of the open space, so that the problem as in the first conventional example does not occur. However, it is necessary to use a thin silicon wafer 71, and the thin silicon wafer 71 is liable to be broken, and the bonding is difficult, which tends to reduce the yield.

Accordingly, the present invention has been made to solve the above-mentioned problems, and has been made without increasing the cost.
An object of the present invention is to provide a method for manufacturing a silicon vibrator in which handling of a silicon substrate is extremely easy. In addition, the present invention provides a method for manufacturing a silicon vibrating body that does not increase the cost, and that can easily handle a silicon substrate and that can install components such as electrodes without separately bonding the substrate. The purpose is to provide.

[0012]

According to a first aspect of the present invention, the vibrating portion, the fixed portion, and the vibrating portion are supported on the one surface of the first silicon wafer having a thickness greater than a predetermined thickness of the vibrating portion. A first step of forming a mask pattern having a planar shape with a beam portion to be formed, and etching a portion other than the mask pattern on one surface of the first silicon wafer deeper than a predetermined thickness of the vibrating portion to form a concave portion. A second step of forming;
A third step of forming a protective film on at least one surface of the second silicon wafer; and removing the protective film on one surface of the second silicon wafer while leaving a planar pattern of the fixing portion. A fourth step of forming a mask pattern having a planar shape of the fixing portion, a fifth step of etching a portion other than the mask pattern on one surface of the second silicon wafer until a through hole is formed, In the case where the protective film is formed on both surfaces of the wafer, a sixth step of removing the protective film on the other surface of the second silicon wafer is performed.
And a seventh step of aligning and joining one surface of the first silicon wafer on which the concave portion is formed, and one of the surfaces of the second silicon wafer such that the shapes of the fixed portions match. An eighth step of grinding the other surface side of the first silicon wafer to a position just before a predetermined thickness of the vibrating portion, and then mirror-finish the other surface, and the other surface of the mirror-finished first silicon wafer A ninth step of etching the side to a predetermined thickness of the vibrating portion.

According to a second aspect of the present invention, a flat surface of the vibrating portion, a fixed portion, and a beam portion supporting the vibrating portion with respect to the fixed portion is provided on one surface of the first silicon wafer having a thickness greater than a predetermined thickness of the vibrating portion. A first step of forming a mask pattern having a shape, and a second step of forming a concave portion by etching a portion other than the mask pattern on one surface of the first silicon wafer deeper than a predetermined thickness of the vibrating portion. Removing at least a part of the planar mask pattern of the fixed part from the mask pattern on one surface of the first silicon wafer, and positioning the mask pattern at the position of the fixed part on one surface of the first silicon wafer. A third step of etching until an uneven portion is formed, a fourth step of forming a protective film on at least one of both surfaces of the second silicon wafer, and a step of holding the one surface of the second silicon wafer. A fifth step of forming a planar mask pattern of the fixed portion by removing the film while leaving at least a part of the planar pattern of the fixed portion; and a mask pattern on one surface of the second silicon wafer. A sixth step of etching a part other than the part until a concave part where a component is arranged is formed and a positioning concave and convex part is formed at the position of the fixing part; one surface of the first silicon wafer where the concave part is formed; (2) a seventh step of aligning and joining one surface of the silicon wafer where the concave portion is formed so that the respective positioning concave-convex portions match;
An eighth step of grinding the other surface of the silicon wafer to a position just before a predetermined thickness of the vibrating portion, and then mirror-finishing the silicon wafer; and polishing the other surface of the mirror-finished first silicon wafer by the vibration A ninth step of etching until the portion has a predetermined thickness.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

1 to 10 show a first embodiment of the present invention. FIG. 1A is a perspective view of a micromirror that is a silicon vibrator, and FIG. 1B is a cross-sectional view taken along line AA of FIG. 1A. 1 (a) and 1 (b), a micromirror 1 is provided with a vibrating portion 3 having at least one surface serving as a mirror surface in an internal space of a fixed portion 2 of a rectangular frame body. , 4, and is swingably supported by the fixed part 2. When a vibration force is applied to the vibrating section 3 by a driving unit (not shown), the vibrating section 3 vibrates around the beam section 4 due to torsional deformation of the beam section 4, and the vibration of the vibrating section 3 causes the mirror surface to vibrate. The reflection angle of the irradiated light beam is changed and the light beam is polarized. The thickness of the vibrating section 3 and the beam section 4 is several tens to 1 in order to be small and vibrate at high speed.
The thickness is set to about 00 microns.

Next, a method of manufacturing the micromirror 1 will be described with reference to FIGS. First silicon wafer 1
Reference numeral 0 denotes a thickness which is larger than a predetermined thickness of the vibrating portion 3 and the beam portion 4 and is hard to be damaged and easy to handle, and at least one surface of the first silicon wafer 10 is mirror-finished. First, as shown in FIG. 2, a fixed portion 2, a vibrating portion 3, and a beam portion 4 for supporting the vibrating portion 3 with respect to the fixed portion 2 are provided on one mirror-finished surface of the first silicon wafer 10. Planar mask pattern 11 (shown in black in FIG. 2)
Is formed (first step). The mask pattern 11 is formed by a method such as photolithography.

Next, as shown in FIG. 3, one side of the first silicon wafer 10 and a portion other than the mask pattern 11 are etched at least deeper than the predetermined thickness of the vibrating portion 3 and the beam portion 4 (see FIG. 3). 2nd process). On one surface of the first silicon wafer 10, two concave portions 12 are formed. This etching is performed by a method such as reactive ion etching (RIE).

Next, the second silicon wafer 13 has a rigid thickness (thickness of about several hundred microns) as the fixing portion 2, and at least one surface of the second silicon wafer 13 is mirror-finished. Use Therefore, it naturally has a thickness that is not easily damaged and easy to handle. And
As shown in FIG. 4, protective films 14 and 15 are formed on both surfaces of the second silicon wafer 13 (third step). The protective films 14 and 15 need only be ones that are not attacked by the silicon etchant in order to perform chemical etching using an etchant. For example, SiO ₂ by thermal oxidation is convenient in the process.

Next, as shown in FIG. 5, the protection film 14 on one surface of the second silicon wafer 13 is
The mask pattern 16 having the planar shape of the fixed portion 2 is formed by removing the pattern 2 while leaving the pattern (step 4).

Next, as shown in FIG. 6, a portion other than the mask pattern 16 on one surface of the second silicon wafer 13 is
Etch until it penetrates (5th step). This etching is performed by chemical etching using a solution such as KOH or TMAH.
It is formed on the silicon wafer 13. Here, the through hole 17
When using anisotropic etching of chemical etching,
Since the silicon crystal surface forms a tapered shape, the size of the entrance of the through hole 17 that opens on the surface on the joining side (the lower surface in the drawing, which is a mirror-finished surface in the first embodiment) is It is necessary to determine the size of the fixed portion of the mask pattern 11 formed on the first silicon wafer 10 so as to match the size of the shape.

Next, as shown in FIG. 7, the protective film 15 on the other surface (this surface is a mirror-finished surface) of the second silicon wafer 13 is removed (sixth step).

Next, as shown in FIG. 8, one surface of the first silicon wafer 10 where the concave portion 12 is formed and the other surface of the second silicon wafer 13 are positioned so that the shapes of the fixing portions match. They are joined and joined (seventh step). Here, the first silicon wafer 10 and the second silicon wafer 13
The first silicon wafer 1 is positioned through the through hole 17.
Since the pattern of 0 can be seen, it is possible to match with a normal microscope. Further, as the bonding method, anodic bonding, glass bonding, or the like can be used.

Next, as shown in FIG. 9, the other surface of the first silicon wafer 10 opposite to the bonding surface is
Then, the grinding process is performed until the beam portion 4 reaches a predetermined thickness, and then the mirror processing is performed (eighth step). Here, when the vibrating part 3 and the beam part 4 are ground by mechanical processing such as grinding, the vibrating part 3 and the beam part 4 appear because the vibrating part 3 and the beam part 4 are damaged by the processing load. Grinding is finished at a point just before, and mirror finishing is performed leaving a margin for removal. However, if the amount of removal is too small, the portion may bend, resulting in uneven thickness or breakage.

Next, as shown in FIG. 10, the other side of the mirror-finished first silicon wafer 10 is etched until the vibrating portion 3 and the beam portion 4 have predetermined thicknesses (ninth step). This etching is, for example, reactive ion etching. In the ion etching or the like, since no load is applied to the vibrating portion 3 and the beam portion 4, there is no breakage.
This etching may be chemical etching, but it is difficult to control the completion of the etching, and the surface may be roughened. Therefore, ion etching, particularly, high-speed reactive ion etching is desirable. Through the above steps, the manufacture of the micro mirror 1 shown in FIG. 1 is completed.

In the above example, the second silicon wafer 13
Are formed on both surfaces of the second silicon wafer 13, but the protection film is formed only on one surface of the second silicon wafer 13. By removing, a planar mask pattern of the fixing part 2 is formed (fourth step). Then, a through hole may be formed by a method of high-speed reactive ion etching such as an inductively coupled plasma etching method (fifth step). In this case, the sixth step becomes unnecessary.

According to the first embodiment, the inexpensive first silicon wafer 10 and second silicon wafer 13 are used as the silicon substrate, and the first silicon wafer 10
In positioning the silicon wafer 13 and the second silicon wafer 13, the through hole 1
7, the pattern of the first silicon wafer 10 can be seen, and can be adjusted with a normal microscope or the like.
For example, since special equipment such as a double-sided exposure machine is not required, it can be manufactured at low cost. Also, the thinner first silicon wafer 1
0 itself is thicker than the predetermined thickness of the vibrating part 3 and the beam part 4, so that it is hard to be damaged and handling of the silicon substrate is very easy.

FIGS. 11 to 19 show a second embodiment of the present invention. FIG. 11A is a perspective view of a micromirror that is a silicon vibrator, and FIG. 11B is a view taken along line BB of FIG. 11A.
It is a line sectional view. In FIGS. 11A and 11B, the micromirror 1 has a vibrating portion 3 having at least one surface serving as a mirror surface disposed in an internal space of the fixed portion 2 of the rectangular frame body. , 4, and is swingably supported by the fixed part 2. Below the vibrating part 3, there is provided a component placement part 5 integrated with the fixed part 2, and the component placement part 5 has an electrode 6 of a drive part as a component (FIG. 11A,
(Shown by a broken line in (b)). When a vibration force is applied to the vibrating section 3 from the driving section, the vibrating section 3 vibrates around the beam section 4 due to torsional deformation of the beam section 4, and the vibration of the vibrating section 3 irradiates the mirror surface. The reflection angle of the light beam is changed and the light beam is polarized. The thickness of the vibrating section 3 and the beam section 4 is set to a thickness of about several tens to 100 microns in order to achieve small size and high-speed vibration.

Next, a method for manufacturing the micromirror 1 will be described with reference to FIGS. The first silicon wafer 10 is thicker than the predetermined thickness of the vibrating portion 3 and the beam portion 4 and has a thickness that is not easily damaged and is easy to handle, and at least one surface of the first silicon wafer 10 is mirror-finished.
First, as shown in FIG. 12, a fixed portion 2, a vibrating portion 3, and a beam portion 4 for supporting the vibrating portion 3 with respect to the fixed portion 2 are provided on one mirror-finished surface of the first silicon wafer 10. A planar mask pattern 20 (indicated by hatching in FIG. 12) is formed (first step). The mask pattern 20 is formed by, for example, a method such as photolithography.

Next, as shown in FIG. 13, one surface of the first silicon wafer 10 and portions other than the mask pattern 20 are etched deeper than a predetermined thickness of the vibrating portion 3 (second step). On one surface of the first silicon wafer 10,
Concave portions 21 are formed at two places. This etching is performed by a method such as reactive ion etching (RIE).

Next, as shown in FIG. 14, in the mask pattern on one surface of the first silicon wafer 10,
Removing the inner peripheral portion of the mask pattern 20 having a planar shape of
As shown in FIG. 15, the first silicon wafer 10 is etched until the positioning uneven portion 22 is formed at the position of the fixed portion 2 on one surface (third step).

Next, the second silicon wafer 13 has a rigid thickness (thickness of about several hundreds of microns) as the fixing portion 2, and at least one surface of the second silicon wafer 13 is mirror-finished. Use Therefore, it naturally has a thickness that is not easily damaged and easy to handle. And
As shown in FIG. 16, protective films 23 and 24 are formed on both surfaces of the second silicon wafer 13 (fourth step). The protective films 14 and 15 need only be ones that are not attacked by the silicon etchant in order to perform chemical etching using an etchant. For example, SiO ₂ by thermal oxidation is convenient in the process. However, when the interval between the vibrating section 3 and the component placement section 5 on which the electrode 6 as a component is placed by electrostatic driving or the like may be small, a technique such as ion etching may be used.
In that case, the protective film 24 is not required on the other surface.

Next, as shown in FIG. 17, the protective film 23 on one surface (this surface is a mirror-finished surface) of the second silicon wafer 13 is placed on the inner peripheral side of the planar pattern of the fixing portion 2. By leaving and removing, a mask pattern 25 having a planar shape on the inner peripheral side of the fixed portion 2 is formed (fifth step).

Next, as shown in FIG. 18, a portion other than the mask pattern 25 on one surface of the second silicon wafer 13 is formed with a concave portion 26 for disposing components, and a positioning uneven portion 27 is formed at a fixed portion. Etch until possible (sixth step). This etching uses chemical etching, ion etching, or the like. The etching depth is the first
The value obtained by subtracting the step difference between the fixed part 2 and the vibrating part 3 of the silicon wafer 10 is determined so as to have a predetermined depth. In the second embodiment, a predetermined electrode 6 is formed in the concave portion 26 in order to manufacture an electrostatically driven micro mirror.

Next, as shown in FIG. 19, one surface of the first silicon wafer 10 on which the concave portion 21 is formed and the other surface of the second silicon wafer 13 on which the concave portion 26 is formed are respectively positioned by positioning unevenness. The parts 22 and 27 are aligned and joined so that they match (seventh step). In the second embodiment, since the positioning of the two silicon wafers 10 and 13 is performed by the positioning uneven portions 22 and 27, the positioning can be easily performed without using a microscope or the like as in the first embodiment. Further, as the bonding method, anodic bonding, glass bonding, or the like can be used.

Next, similarly to the eighth step (see FIG. 9) of the first embodiment, the other surface, which is opposite to the bonding surface of the first silicon wafer 10, is fixed to the vibrating portion 3 and the beam portion 4 by a predetermined amount. Grinding is performed until the thickness is reduced, and then mirror-finished (eighth step). Here, when the vibrating portion 3 and the beam portion 4 are ground to a thickness at which the vibrating portion 3 and the beam portion 4 appear by mechanical processing such as grinding, the vibrating portion 3 and the beam portion 4 are damaged by a processing load.
The grinding is finished just before the beam portion 4 appears, and mirror finishing is performed leaving a margin for removal. However, if the amount of removal is too small, the portion may bend, resulting in uneven thickness or breakage.
Micron or more is desirable.

Next, similarly to the ninth step (see FIG. 10) of the first embodiment, the other side of the mirror-finished first silicon wafer 10 is brought to a predetermined thickness of the vibrating section 3 and the beam section 4. Etching (ninth step). This etching is, for example, reactive ion etching. In the ion etching or the like, since no load is applied to the vibrating portion 3 and the beam portion 4, there is no breakage. Also, this etching may be chemical etching, but it is difficult to control the end of the etching,
In addition, ion etching, particularly, high-speed reactive ion etching is desirable because the surface may be roughened. The micro mirror 1 shown in FIG.
Is completed.

According to the second embodiment, the inexpensive first silicon wafer 10 and second silicon wafer 13 are used as the silicon substrates, and the first silicon wafer 10
The positioning between the silicon wafer 13 and the second silicon wafer 13 is performed by the positioning concave and convex portions 22 and 27, and special equipment such as a double-sided exposure machine is not required. Further, since the thinner first silicon wafer 10 itself is thicker than the predetermined thickness of the vibrating part 3 and the beam part 4, it is hard to be damaged, and the handling of the silicon substrate is very easy. Furthermore, since the component arrangement part 5 is provided below the vibration part 3,
Components such as the electrodes 6 can be installed without separately bonding the substrates.

According to the second embodiment, the two silicon wafers 10 and 13 are provided with the frame-shaped positioning uneven portions 22 and 27 in the fixing portion 2. Any material can be used as long as the two silicon wafers 10 and 13 can be aligned.

In the first embodiment, the positioning of the two silicon wafers 10 and 13 is performed by visual recognition from the through hole 17, but the positioning uneven portions 22 and 27 are provided as in the second embodiment. You may go.

According to the first and second embodiments, the case where a micromirror is manufactured as a silicon vibrator has been described. However, the present invention can be applied to devices such as an acceleration sensor and an angular velocity sensor.

According to the first and second embodiments, 1
Although it has been described that a plurality of micromirrors (silicon vibrators) are manufactured, a plurality of micromirrors (silicon vibrators) are actually processed on a wafer at the same time. By simultaneously processing a plurality of pieces, mass productivity can be improved, material costs can be reduced, and equipment investment can be reduced.

[0042]

As described above, according to the first aspect of the present invention, the vibrating portion, the fixed portion and the fixed portion are provided on one surface of the first silicon wafer having a thickness greater than the predetermined thickness of the vibrating portion. A first step of forming a planar mask pattern with a beam portion supporting the vibrating portion, and etching a portion other than the mask pattern on one surface of the first silicon wafer deeper than a predetermined thickness of the vibrating portion. A second step of forming a concave portion by forming a protective film on at least one surface of the second silicon wafer; and a step of forming the protective film on one surface of the second silicon wafer by A fourth step of forming a mask pattern having a planar shape of the fixing portion by removing the shape pattern, and forming a through-hole in a portion other than the mask pattern on one surface of the second silicon wafer. A fifth step of etching the first silicon wafer, and a sixth step of removing the protective film on the other surface of the second silicon wafer when the protective films are formed on both surfaces of the second silicon wafer. A seventh step of aligning and joining the one surface on which the concave portion is formed and one of the surfaces of the second silicon wafer so that the shapes of the fixed portions match, and An eighth step of grinding the other surface side to a point just before the vibration portion has a predetermined thickness and then mirror-finish the same, and moving the other surface side of the mirror-finished first silicon wafer to a predetermined thickness of the vibration portion. A ninth step of etching to a thickness, so that inexpensive first and second silicon wafers are used as the silicon substrate, and the first and second silicon wafers are used together. In positioning with EHA, the pattern of the first silicon wafer can be seen from the through hole, and can be adjusted with a normal microscope. For example, since special equipment such as a double-sided exposure machine is not required, cost increases. Further, since the thinner first silicon wafer itself is thicker than the predetermined thickness of the vibrating portion, the handling of the silicon substrate is very easy.

According to the second aspect of the present invention, the vibrating portion, the fixed portion, and the beam portion supporting the vibrating portion with respect to the fixed portion are provided on one surface of the first silicon wafer having a thickness greater than the predetermined thickness of the vibrating portion. A second step of forming a concave portion by etching a portion of one surface of the first silicon wafer other than the mask pattern deeper than a predetermined thickness of the vibrating portion; The step and the first
Within the mask pattern on one side of the silicon wafer,
A third step of removing at least a part of the planar mask pattern of the fixing portion and etching until a positioning uneven portion is formed at a position of the fixing portion on one surface of the first silicon wafer; A fourth step of forming a protective film on at least one surface of both surfaces; and removing the protective film on one surface of the second silicon wafer while leaving at least a part of a planar pattern of the fixing portion. A fifth step of forming a mask pattern having a planar shape of the fixing portion, and forming a concave portion for arranging a component on a portion other than the mask pattern on one surface of the second silicon wafer, and a positioning uneven portion at a position of the fixing portion. A sixth step of etching until the first silicon wafer has a concave portion, and a concave portion of the second silicon wafer has been formed. A seventh step of bonding the surface, each of the positioning concave-convex portions are aligned to match,
Eighth step of grinding the other surface of the first silicon wafer to a position just before the vibration portion has a predetermined thickness, and then mirror-finish the surface, and polishing the other surface of the mirror-finished first silicon wafer. And a ninth step of etching until the vibrating portion has a predetermined thickness. Therefore, inexpensive first and second silicon wafers are used as the silicon substrate, and the first and second silicon wafers are used. Positioning is performed by both positioning concave and convex portions, and no special equipment such as a double-sided exposure machine is required, so that cost is not increased, and the thinner first silicon wafer itself has a predetermined thickness of the vibrating portion. It is very easy to handle the silicon substrate because it is thicker. Furthermore, since the component placement portion is provided below the vibrating portion, components such as electrodes can be installed without separately bonding the substrate.

[Brief description of the drawings]

FIGS. 1A and 1B show a first embodiment of the present invention, in which FIG. 1A is a perspective view of a micromirror, and FIG. 1B is a cross-sectional view taken along line AA in FIG.

FIG. 2 is a perspective view illustrating a first embodiment of the present invention and illustrating a first step of a method for manufacturing a micromirror.

FIG. 3 is a perspective view illustrating the first embodiment of the present invention and illustrating a second step of the method for manufacturing a micromirror.

FIG. 4 is a perspective view illustrating the first embodiment of the present invention and illustrating a third step of the method for manufacturing a micromirror.

FIG. 5 is a perspective view illustrating the first embodiment of the present invention and illustrating a fourth step of the method for manufacturing a micromirror.

FIG. 6 is a perspective view illustrating the first embodiment of the present invention and illustrating a fifth step of the method for manufacturing a micromirror.

FIG. 7 is a perspective view illustrating the first embodiment of the present invention and describing the sixth step of the method for manufacturing a micromirror.

FIG. 8 is a perspective view illustrating the first embodiment of the present invention and illustrating a seventh step of the method of manufacturing a micromirror.

FIG. 9 is a schematic cross-sectional view illustrating the first embodiment of the present invention and explaining the eighth step of the method for manufacturing a micromirror.

FIG. 10 is a schematic cross-sectional view showing the first embodiment of the present invention and illustrating a ninth step of the method for manufacturing a micromirror.

11A and 11B show a second embodiment of the present invention, in which FIG. 11A is a perspective view of a micromirror, and FIG. 11B is a cross-sectional view taken along line BB of FIG.

FIG. 12 is a perspective view illustrating a second embodiment of the present invention and illustrating a first step of a method for manufacturing a micromirror.

FIG. 13 is a perspective view illustrating a second embodiment of the present invention and illustrating a second step of the method for manufacturing a micromirror.

FIG. 14 is a perspective view illustrating the second embodiment of the present invention and illustrating the first half of the third step in the method for manufacturing a micromirror.

FIG. 15 is a perspective view illustrating the second embodiment of the present invention and explaining the latter half of the third step in the method for manufacturing a micromirror.

FIG. 16 is a perspective view illustrating the second embodiment of the present invention and describing the fourth step of the method for manufacturing a micromirror.

FIG. 17 is a perspective view illustrating the second embodiment of the present invention and describing the fifth step of the method for manufacturing a micromirror.

FIG. 18 is a perspective view illustrating a second embodiment of the present invention and illustrating a sixth step of the method for manufacturing a micromirror.

FIG. 19 is a schematic cross-sectional view showing a second embodiment of the present invention and illustrating the seventh step of the method for manufacturing a micromirror.

FIG. 20 is a perspective view of a conventional micro mirror manufactured from a silicon substrate.

FIGS. 21A to 21F are cross-sectional views showing manufacturing steps of a first conventional example.

FIGS. 22A to 22G are cross-sectional views showing manufacturing steps of a second conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Micromirror (silicon vibrating body) 2 Fixed part 3 Vibrating part 4 Beam part 6 Electrode (part) 10 1st silicon wafer 11 Mask pattern 12 Depression 13 Second silicon wafer 14, 15 Protective film 16 Mask pattern 17 Through hole 20 Mask Pattern 21 concave portion 22 positioning uneven portion 23, 24 protective film 25 mask pattern 26 concave portion 27 positioning uneven portion

Claims (2)

[Claims] 1. A mask pattern having a planar shape of said vibrating portion, a fixed portion, and a beam portion supporting said vibrating portion with respect to said fixed portion, on one surface of a first silicon wafer thicker than a predetermined thickness of said vibrating portion. A first step of forming; a second step of etching a portion other than the mask pattern on one surface of the first silicon wafer deeper than a predetermined thickness of the vibrating portion to form a concave portion; Forming a protective film on at least one surface of the second silicon wafer; and removing the protective film on one surface of the second silicon wafer while leaving the planar pattern of the fixed portion flat. A fourth step of forming a mask pattern having a shape; and a fifth step of etching a portion other than the mask pattern on one surface of the second silicon wafer until a through hole is formed.
A step of removing the protective film on the other surface of the second silicon wafer when the protective film is formed on both surfaces of the second silicon wafer; and forming the concave portion of the first silicon wafer. A seventh step of aligning and bonding the one surface and one of the surfaces of the second silicon wafer so that the shapes of the fixing portions match each other; An eighth step of performing grinding processing before reaching a predetermined thickness of the vibrating portion and then performing mirror finishing, and etching the other surface side of the mirror-finished first silicon wafer until the predetermined thickness of the vibrating portion is obtained. 9. A method for manufacturing a silicon vibrator, comprising: 2. A mask pattern having a planar shape of said vibrating portion, a fixed portion, and a beam portion supporting said vibrating portion with respect to said fixed portion on one surface of a first silicon wafer having a thickness greater than a predetermined thickness of said vibrating portion. A first step of forming; a second step of etching a portion other than the mask pattern on one surface of the first silicon wafer deeper than a predetermined thickness of the vibrating portion to form a concave portion; In the mask pattern on one surface of the wafer, at least a part of the planar mask pattern of the fixing portion is removed, and a positioning uneven portion is formed at the position of the fixing portion on one surface of the first silicon wafer. A third step of etching, a fourth step of forming a protective film on at least one of both surfaces of the second silicon wafer, and the step of forming the protective film on one surface of the second silicon wafer by the solidification. A fifth step of forming a planar mask pattern of the fixed portion by removing at least a part of the planar pattern of the portion, and a portion other than the mask pattern on one surface of the second silicon wafer; A sixth step of forming a concave portion for arranging components and etching until a positioning concave-convex portion is formed at the position of the fixing portion; and one surface of the first silicon wafer where the concave portion is formed;
A seventh step of aligning and joining one surface of the second silicon wafer where the concave portion is formed so that the respective positioning uneven portions match, and connecting the other surface of the first silicon wafer to the vibrating portion. An eighth step of performing a grinding process before reaching a predetermined thickness of the first silicon wafer, and then performing a mirror finishing process; A method for manufacturing a silicon vibrating body, comprising: