JP2001260098A - Method of manufacturing for fine structural body and image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method capable of accurately controlling thickness when a fine structural body is formed by pattern transfer and of manufacturing a high-quality device with a high yield and at a low cost. SOLUTION: A preliminary process for forming a resin layer 35a by spin- coating a resin agent 35 before forming a support structure of an optical element on a surface 34a of a sacrifice layer 34 for forming an actuator 6 is provided. Thereby, the resin layer 35a having a uniform thickness can be formed on the surface 34a of the board 20a before pressing a transfer pattern, so that the accuracy of thickness can be improved. Since the need of the force for expanding the resin agent 35 is obviated, the pressure required for pattern transfer can be reduced to around one tenth. Thereby, balance can easily be secured, the distortion or the like of the transfer pattern in pressing it can be eliminated, film thickness control can easily be achieved and the yield can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a micro replica technique for forming a resin microstructure by die transfer.

[0002]

2. Description of the Related Art In recent years, miniaturization of video projectors such as data projectors and video projectors has been further advanced, and the size thereof has also been extremely reduced. For this reason, optical elements on the order of microns or submicrons and video display devices equipped with the same have been actively developed. Similarly, in optical communication, optical arithmetic, optical recording devices such as hologram memories, optical printers, and the like, devices for systems requiring high resolution and high-speed response require microstructures on the order of microns or even smaller submicrons (microstructures). The development of an optical device equipped with a) has been earnestly advanced.

[0003]

FIG. 11 shows an evanescent wave (evanescent light) developed by the present applicant.
1 shows an outline of an image display device (evanescent light switching device) that modulates light by utilizing the above. The image display device 50 is a device in which a plurality of optical switching elements (optical switching mechanisms) 10 are two-dimensionally arranged. Each of the optical switching elements 10 is capable of transmitting the reflected light 2 by totally reflecting the light alone. Element 3 capable of modulating light by approaching and moving away from a simple light guide plate (light guide) 1
And an actuator 6 for driving the optical element section 3. Then, an optical element (micro-optical element) and an actuator (micro-actuator) are manufactured on the order of microns, and a device in which these are arranged in an array such as two-dimensionally is integrated into a chip size, thereby forming a layer of the optical element 3 and an actuator. A semiconductor substrate 20 in which a driving circuit and a digital storage circuit (storage unit) for driving an actuator are formed in layer 6
, And can be integrated as one image display device.

[0004] The image display device 50 of the present example using evanescent light will be described in more detail. To explain based on the individual optical switching elements 10, FIG.
1, the optical switching element 10a shown on the left side is in an on state, and the optical switching element 10b shown on the right side is in an off state. The optical element 3 has a surface (contact surface or extraction surface) 3a that is in close contact with the surface (total reflection surface) 1a of the light guide plate 1 (light guide) that functions as a waveguide, and this surface 3a is the total reflection surface 1a. A V-shaped reflecting prism (microprism) 4 that extracts an evanescent wave that leaks out upon close contact and reflects the light in a direction substantially perpendicular to the light guide plate 1 and supports the V-shaped prism 4 A supporting structure 5.

The actuator 6 is capable of electrostatically driving the optical element 3. An upper electrode 7 to which a support structure 5 of the optical element 3 is mechanically connected, and a lower electrode 8 opposed to the upper electrode 7. And And the lower electrode 8,
The anchor plate 9 of the upper electrode 7 is stacked on the uppermost surface 20a of the semiconductor substrate 20. The upper electrode 7 is supported by a support 11 extending upward from the anchor plate 9,
A space is formed between the lower electrode 8 and the upper electrode 7. Therefore, for example, when the upper electrode 7 is grounded via the plate 9 and a potential or electric charge is applied to the lower electrode 8 from the drive unit 21, the upper electrode 7 moves downward, and the optical element section 3 is driven in conjunction with this. Move away from the light plate 1 (second position).
On the other hand, the upper electrode 7 partially has a function as an elastic member, and when the potential or electric charge applied to the lower electrode 8 from the storage unit 21 is removed or released, the upper electrode 7 rises from the lower electrode 8. The electrode 7 separates, and the optical element portion 3 comes into close contact with the light guide plate 1 due to the elasticity of the upper electrode 7 (first position).

As shown in FIG. 11, illumination light 2 is supplied from a light source to a light guide plate 1 at an angle at which the illumination light 2 is totally reflected by a total reflection surface 1a. Light is repeatedly totally reflected on the side 1a facing the light switching portion 3 and on the upper surface (emission surface), and the inside of the light guide plate 1 is filled with light rays. Therefore, in this state, the illumination light 2 is macroscopically confined inside the light guide plate 1 and propagates therein without any loss. On the other hand, microscopically, in the vicinity of the surface 1a of the light guide plate 1 which is totally reflected, the illumination light 2 leaks from the light guide plate 1 only for a very short distance of about the wavelength of light, and changes its course. The phenomenon of returning to the inside of the light guide plate 1 again occurs. The light leaked from the surface 1a in this manner is generally called an evanescent wave. This evanescent wave
It can be taken out by bringing another optical member close to the total reflection surface 1a at a distance of about the wavelength of light or less. The optical switching element 10 of the present embodiment is designed to modulate light transmitted through the light guide plate 1 at high speed, that is, to switch (on / off) using this phenomenon.

Therefore, in the optical switching element 10a, since the optical element 3 is at the first position in contact with the total reflection surface 1a of the light guide plate 1, evanescent waves can be extracted by the surface 3a of the optical element 3. For this reason, the light 2 extracted by the microprism 4 of the optical element 3 is changed in angle and becomes the output light 2a. On the other hand, the optical switching element 10
In b, voltages having different polarities are applied to the upper and lower electrodes 7 and 8 by the drive unit 21, and these electrodes 7 and 8 are applied.
The optical element 3 is moved to the second position apart from the light guide plate 1 by the electrostatic force acting during the period. Therefore, the evanescent wave is not extracted by the optical element 3, and the light 2 does not exit from the inside of the light guide plate 1.

An optical switching element using an evanescent wave functions as a device that can switch light by itself, but as shown in FIG. 11, these are arranged in a one-dimensional or two-dimensional direction, and further arranged in a three-dimensional manner. It is configured to be able to. In particular, by arranging them two-dimensionally in a matrix or array, it is possible to provide an image display unit 55 capable of displaying a two-dimensional image similarly to liquid crystal or DMD. And
In the image display device 50 using the evanescent light, the moving distance of the optical element 3 is on the order of submicron.
The present invention can be used as an optical modulator having a response speed one digit or more faster than that of liquid crystal, and it is possible to provide a projector or a direct-view video display using the same. Further, an optical switching element 10 using evanescent light
Can turn on and off light by almost 100% with a movement on the order of submicrons, and can express a very high-contrast image. Therefore, it is easy to increase the temporal resolution, and a high-contrast image display device can be provided.

Further, as described above, an image display device 50 having a configuration in which the actuators 6 and the optical elements 3 arranged in an array on the semiconductor integrated substrate 20 in which the drive circuit and the like are built is provided in one chip. It is possible to That is, the video display unit 55 can be supplied by assembling the video display device 50, which is a micromachine or an integrated device, in which microstructures such as the actuator 6 and the optical element 3 are constructed on the semiconductor substrate 21, and the light guide 1. By incorporating the above, it is possible to provide a projector which can display a high-contrast image with a high operation speed and a high resolution.

A switching device using evanescent light is not limited to the one shown in FIG.
In addition to the upper electrode 7 and the lower electrode 8, an image display device including an actuator 6 configured to provide an intermediate electrode that moves between the electrodes and to drive the optical element 3 in conjunction with the intermediate electrode is also possible. . The video display device using the evanescent light has a merit that the configuration of the actuator 6 is complicated but can be driven at a low voltage. Further, instead of an electrostatic actuator using electrodes, an actuator can be configured using a piezo element, and some actuators have been considered. Therefore, hereinafter, in this specification,
For simplicity, the description will be made based on an actuator of an electrostatic drive type with upper and lower electrodes, but the configuration of the actuator is not limited to this.

An image display device using evanescent light has excellent characteristics as described above. However, there are several problems to be solved in order to put this video display device into practical use, and one of them is to improve the yield and reduce the cost. That is, since each optical switching element constituting the video display device displays a pixel, if there is a defect, the image quality deteriorates. Therefore, it is important to manufacture a high-yield video display device having no or few pixel defects. In addition, by improving the yield, it is possible to provide a product free from pixel defects at low cost.

However, an image display device using evanescent light is of a type in which a large number of micro-optical elements are driven by an actuator as described above, and the light is turned on / off by a movement of a submicron order or less with respect to the total reflection surface. I do. Therefore, a micro optical element having high dimensional accuracy is required, while speeding up is easy. Further, it is necessary to manufacture a micro optical element using a material having excellent optical properties such as excellent light transmittance. In order to satisfy these requirements, the inventors of the present application have developed a micro replica technology for forming a micro structure by transferring a mold to a resin layer.

When manufacturing a device in which small elements are arranged in an array, a wafer having a size of 5 inches or 8 inches is used as a substrate, and devices having a chip size are arranged on the wafer, and a number of devices (chips) are formed at a time. ) Is economical to produce simultaneously.

However, in order for each micro-optical element to have substantially the same thickness in any switching element of any device arranged on the wafer,
A uniform pressure must be applied to the wafer and all parts of the transfer mold that are pressed against the wear. For this purpose, it is necessary to control the parallelism between the upper and lower wafers and the pressing surface of the transfer die in units of seconds (angles), but this is not possible. Therefore, microscopically, it is possible to manufacture a switching element or device with high accuracy by the micro-replica technology, but it is impossible to manufacture a device with the same accuracy when mass-produced.

For example, FIG. 12 shows an example of an experiment conducted by the inventors of the present application to manufacture a fine structure portion by die transfer. In this experiment, a wafer size glass substrate was used as the first substrate 90 shown in FIG.
As the first substrate 91, a transfer die that transfers a shape is used. The surface of each of these substrates is subjected to a surface treatment with a silicon coupling agent in order to increase the adhesion. For example, KBM5103 manufactured by Shin-Etsu Chemical Co., Ltd. is applied by a spinner and baked at 100 ° C. for 10 minutes.

Next, as shown in FIG. 12B, a resin agent 98 is placed between the two surface-treated substrates 90 and 91, respectively. As the resin agent 98, an ultraviolet curable monomer, an acrylate or methacrylate monomer, or the like is used. For example, there is a commercially available acrylate-based V-2400 PET manufactured by Nippon Steel Chemical Co., Ltd.

Next, a pressure of about 0.01 kg / mm ² is applied from both sides. After pressure is applied, ultraviolet rays (UV) having a wavelength of about 350 nm are irradiated at 1000 mJ / cm ² and cured by light or heat.

When the transfer type substrate 91 is removed, FIG.
As shown in (c), a sample 99 of a microstructure in which a resin layer 95 having a shape of a predetermined micron order or less is formed.

The thickness variation of the sample 99 is about 10 μm with respect to the design value. For this reason, it is hard to say that an optical device using evanescent light is suitable as a method that can be manufactured with a similar yield at a high yield. Also,
Due to the fact that the optical switching element, especially the optical element, is thicker or thinner than the desired thickness, the characteristics of the optical element, device or chip having the optical switching element manufactured by this method are not as designed.

The problem that the thickness cannot be controlled with high precision as described above also occurs when mass-producing other devices, for example, when applied as a technology for manufacturing a micromachine for switching a microvalve. Must be resolved.

Therefore, in the present invention, when mass-producing a device having a fine structure by the micro-replica technique, the thickness can be controlled with high accuracy, and a high-quality device can be manufactured with good yield and low cost. It is an object of the present invention to provide a method for manufacturing a microstructure.

In particular, in a video display device employing an optical switching element utilizing evanescent light capable of high-speed switching, as described above, sub-micron-order film thickness control is required, and such a device has a high yield. It is an object of the present invention to provide a production method capable of supplying the liquid stably.

[0023]

Therefore, in the present invention, when forming a fine structure by die transfer, a preparation for forming a resin layer by spin coating or flexographic printing of a resin agent on a substrate in advance is provided. A process is provided. That is, the method for manufacturing a microstructure according to the present invention includes a step of forming a microstructure by a mold transfer in which a resin layer is sandwiched between a plurality of substrates and pressing, and before that, a resin is formed on at least one substrate. And forming a resin layer by spin coating or flexographic printing of the agent.

Spin coating or flexographic printing is an established technique in terms of keeping the film thickness constant. In the manufacturing method of the present invention, a resin layer having a uniform film thickness is formed on a substrate before the transfer mold is pressed. Can be formed. Therefore, the accuracy of the thickness of the resin layer can be secured without pressing the transfer die, and only the shape may be formed by the transfer die. Therefore, the transfer die can be pressed with a small pressure, and the thickness error accompanying the transfer die can be minimized. This effect is significant in that the pressure value for mold transfer can be reduced by one to two orders of magnitude, since a force that needed to expand the resin layer was conventionally not required when transferring the mold. Is appearing. Therefore, it is easy to maintain the pressure balance, and the difference is reduced. As a result, there is no distortion of the transfer mold at the time of pressing, the film thickness can be easily controlled, and the yield is improved. Further, by spreading the resin agent on the substrate in advance, it is possible to prevent the occurrence of unevenness (pressure unevenness) on the surface. Also in this regard, a uniform film thickness can be accurately managed, and the yield can be improved.

For this reason, according to the manufacturing method of the present invention, a resin fine structure can be mass-produced with a precision on the order of microns or submicrons. Therefore, the manufacturing method of the present invention is suitable for manufacturing a microstructure of a micro optical system, particularly, a micro optical element array in which optical elements are arranged in an array.

When a micro optical element or an optical switching element described below is formed on a semiconductor substrate by using the manufacturing method of the present invention, one of the substrates is a semiconductor substrate on which an actuator array is manufactured in advance. Substrates are also included. The other side of the substrate is a transfer type that defines the shape of the micro optical element. A substrate on which spin coating or the like is performed is a semiconductor substrate on which an integrated circuit is formed,
Either one of the transfer molds for transferring the shape may be used, or both of these substrates may be used.

Further, in the method for manufacturing a microstructure according to the present invention, in the step of molding the microstructure by die transfer,
A so-called 2P method (Photo-polymerization) including a step of curing the resin by light while the substrate is pressed.
And a microstructure on the order of submicrons can be easily obtained.

In the preparation step, it is desirable to dissolve the resin agent in an organic solvent, for example, dissolve it in an alcohol-based organic solvent, and perform spin coating or flexographic printing. This makes it easier to form a thin resin layer with a uniform thickness on the substrate.

According to the manufacturing method of the present invention, a microstructure can be obtained easily and accurately, so that an optical switching element and a micromachine of another object can be manufactured. When manufacturing an optical switching device in which optical switching elements are arranged in an array,
A resin material is applied on the actuator array in which the microactuators for driving the resin-formed switching units are arranged in an array, and a resin layer is manufactured. Furthermore, an optical switching device can be manufactured by forming a micro optical element as a switching unit driven by an actuator by mold transfer, and arranging the micro optical element array in an array to manufacture a micro optical element array. Furthermore, if the micro-optical element is an element that switches the above-mentioned evanescent light or the like, an image display device using evanescent light can be provided.

That is, according to the present invention, a step of manufacturing, on a substrate, an actuator array in which microactuators are arranged in an array, and arranging micro optical elements in an array from a resin layer using a transfer mold on the actuator array. Manufacturing a micro-optical element array, and, before the micro-optical element array manufacturing step, spin-coating or flexographically printing a resin material on at least one of the actuator and the transfer mold. Accordingly, it is possible to provide a method for manufacturing an image display device having a preparation step of forming a resin layer.

As a result, the yield of a high-quality image display device can be improved. The microactuator is an electrostatic actuator, and the micro optical element uses evanescent light, which is a micro prism that performs optical switching by evanescent light. Video display devices can be mass-produced at low cost.

[0032]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to a method for manufacturing an optical switching device 50 using evanescent light shown in FIG.

First, the actuator 6 is manufactured as shown in FIGS. As shown in FIG. 1, an electrode layer (Al) is formed on an upper surface 20a of a substrate 20 on which CMOS is configured.
The film 31 is deposited. Next, patterning 41 is performed on the electrode layer 31 to form the lower electrode 8 and the anchor portion 9 having a structure also serving as a spring and an upper electrode.

As shown in FIG. 2, a sacrificial layer 32 is deposited on the electrode layer 31. The sacrificial layer 32 is made of amorphous silicon and can be deposited at a temperature of several tens of degrees Celsius to one hundred and several tens degrees Celsius, and a CMOS formed on the underlying semiconductor substrate 20 is formed.
No damage to the circuit. Dimples 42 serving as stoppers are dug in the sacrificial layer 32,
The portion to be a post is patterned 43.

As shown in FIG. 3, on the sacrificial layer 32, a second electrode layer (Al film) 33 serving as a second structural layer for forming the structure 7 serving as both a spring and an upper electrode is deposited. I do. Further, the electrode layer 33 is patterned to form the upper electrode 7 and the post 11. At this stage, a structure as the actuator section 6 is formed on the semiconductor substrate 20. The combination of the materials constituting the sacrificial layer and the electrode layer is not limited to the above. For example, the sacrificial layer may be formed of polyimide instead of amorphous silicon. It is also possible to use silicon oxide for the sacrificial layer and polysilicon for the electrode layer.

Further, as shown in FIG. 4, a second sacrifice layer 34 is deposited on the second electrode layer 33 using the same material as the first sacrifice layer 32, and is patterned. A connection portion 44 with the micro optical element 3 is formed thereon.

At this stage, the fine structure layer (actuator array layer) 2 which functions as the actuator 6
Since 5 has been formed, the process proceeds to a step of forming a microstructure layer functioning as the optical element 3 on the layer 25 by die transfer.

FIGS. 5 to 9 show the outline of the steps for manufacturing the optical element array layer 26 functioning as the optical element 3. In the manufacturing method of this example, a resin is sandwiched between substrates,
The microstructure is formed by die transfer in which pressure is applied from both sides or one side.

As shown in FIG. 5, a resin material 35 is spin-coated on the surface (upper surface) 34a of the sacrificial layer 34 constituting the actuator array layer 25 laminated on the semiconductor substrate 20a so as to have a uniform film thickness. Spread over the resin layer 35a
To form This step is a preparation step (first preparation step) for forming the next support structure.

Further, as shown in FIG. 6, a transfer mold (micro replica) 61 is placed on the resin layer 35a formed in the preparation step, and is pressed. Since the photopolymerizable resin is used for the resin material constituting the resin layer 35a of this example, the shape of the support structure 5 is changed by photo-curing by using the transfer mold 61 which is transparent to light such as ultraviolet rays. Can be manufactured. That is, at this stage, the so-called 2P (Pho
to-polymerization) method.

As shown in FIG. 7, when the transfer mold 61 is removed,
A V-shaped structure 5 is formed to support the desired shape, ie, the microprisms 4 of the optical element 3. Further, a reflective film 46 is formed on the molded support structure 5 by a method such as evaporating aluminum on a portion to be a bottom surface of the microprism 4.

Next, as shown in FIG.
Is formed on the substrate. Since the surface of the microprism 4 also becomes the surface 3a for extracting evanescent light, it is necessary to form the microprism 4 with high precision. Therefore, first, similarly to the above-described first preparation step, the resin material 36 is applied to the upper surface 5a of the support structure 5 by spin coating before pressing by the transfer mold 62, and the resin layer 36a having a uniform thickness is formed.
To form This step is a preparation step (second preparation step) for forming the prism 4 below. Then, the transfer mold 62 is placed on the resin layer 36a and pressed.

Also in the step of forming the prism 4 shown in FIG. 8, a photo-curable (photo-polymerizable) resin agent is used as the molding resin agent 36 in the same manner as described above, By using the transparent transfer mold 62, a shape suitable for a microprism can be manufactured by photocuring treatment (2P method).

As described above, the structure layer (optical element array layer) 26 that functions as the optical element 3 in the process shown in FIG. 8 can be manufactured. Next, as shown in FIG. 9, or individual micro optical elements 3 constituting individual pixels are separated so as to be optical elements of an optical switching element array used as an image display device. First, the resin layers 35a and 36a are separated so that the individual microprisms 4 are separated.
The gap 47 is dug in the vertical direction by plasma etching or the like until the sacrificial layer 34 constituting the actuator array layer 25 appears. Through the gap 47, the sacrificial layer 32 made of amorphous silicon is formed by a method such as dry etching using xenon fluoride (XeF ₂ ) gas or the like.
And 34 are removed. This makes it possible to completely remove the sacrificial layer without causing the problem of adsorption even in a narrow gap between the electrodes or the like, and to reliably form the driving space 12 between the electrodes. Therefore, a reliable actuator 6 can be realized.

The device manufactured by the manufacturing method of the present embodiment is a video display device 50 in which the actuator 6 and the optical element 3 which are fine structure layers are vertically stacked on the semiconductor substrate 20. 50
By combining the light guide plate 1 with the light guide plate 1, it is possible to provide the image display unit 55 based on the technology of the optical switching element 10 using the evanescent light described with reference to FIG.

The inventors of the present application conducted a new experiment on the experimental example described above with reference to FIG. 12 in order to confirm the effect of the manufacturing method of the present invention having a preparation step. This is shown in FIG. First, as shown in FIG. 10A, in the first experimental example, the surface of a glass wafer (substrate) 100 is subjected to a surface treatment with a silicon coupling agent in order to increase the adhesiveness of the surface. In this example, KBM5103 manufactured by Shin-Etsu Chemical Co., Ltd.
Bake for about 0 minutes.

Thereafter, as shown in FIG. 10B, a UV curable resin agent 120 is coated on the substrate 100 by spin coating to a thickness of about 10 μm to form a resin layer 121. The resin agent 120 is preferably a monomer, an acrylate or a methacrylate monomer. For example, a commercially available acrylate-based Nippon Steel Chemical V
-2400 PET. Further, the resin agent 120
It can be dissolved in an appropriate organic solvent and spin-coated. For example, the above acrylate-based ultraviolet-curable resin (V-2400 PET of Nippon Steel Chemical Co., Ltd.) is added to ethylene glycol monoethyl ether acetate for 20 minutes.
%. Thereby, even when a highly viscous resin material is used, a thin film having a predetermined thickness can be easily formed by spin coating.

As shown in FIG. 10C, the resin layer 121 coated on the substrate 100 is
And a transfer mold 110 having a shape formed by etching, and a pressure of about 0.001 kg / mm ² is applied from both sides. After the pressurization, ultraviolet light of 350 nm is irradiated at 1000 mJ / cm ² for photopolymerization.

Then, as shown in FIG. 10D, by releasing the transfer mold 110, a sample 150 having the resin layer 121 formed into a uniform and desired shape can be obtained. The variation in the thickness of the resin layer 121 formed in this manner is 1 μm or less, which is about 1/10 of the variation described with reference to FIG. In addition, since the variation in film thickness can be suppressed to the order of microns or less, it is a manufacturing method suitable for manufacturing an optical switching element requiring accuracy of the order of microns or submicrons as described above. I understand. The optical switching device using evanescent light manufactured by this method has good optical characteristics such as reflectance and response speed, and also has an improved yield.

As described above, the fact that the shape can be stably transferred by the manufacturing method of the present invention also means that the pressure of the transfer mold can be reduced. In other words, by providing a preparation step in which a uniform resin layer is applied by spin coating in advance, it is not necessary to extend the resin agent 120 by pressing the mold when transferring the mold. For this reason, a force for spreading the resin agent 120 over the whole becomes unnecessary, and a desired shape can be sufficiently formed with a pressure of about 0.001 kg / mm ² . On the other hand, in the method described above (see FIG. 12), 0.01 kg
/ Mm ² was required. Therefore, according to the production method of the present invention, the pressure for pressing the transfer mold is 0.001 kg /
The pressure value can be reduced by about one digit to about mm ² . Accordingly, there is no distortion of the transfer mold at the time of pressurization, the film thickness can be easily controlled, and the yield is improved. Further, by spreading the resin agent on the substrate in advance, it is possible to prevent the occurrence of unevenness (pressure unevenness) on the surface. Also in this regard, a uniform film thickness can be accurately managed, and the yield can be improved.

Further, in the preparation step of the first experimental example, a method of applying a resin agent to a layer formed on a semiconductor substrate by spin coating has been described. However, the present invention is not limited to this. , A resin agent may be applied by spin coating. Alternatively, it can be applied to both substrates.

When a resin material is applied to both the semiconductor substrate and the transfer mold, the production can be performed as follows. As in the first experimental example, first, in the second experimental example, the surface is treated with a silicon coupling agent in order to increase the adhesion on the glass wafer (substrate). In this example, KBM5103 manufactured by Shin-Etsu Chemical Co., Ltd.
Bake for about 0 minutes. Thereafter, an ultraviolet curable resin agent is coated on the substrate to a thickness of about 5 μm by spin coating.

In addition, the transfer-type substrate (molding surface), which is formed by etching the silicon substrate, has
Similarly, an ultraviolet curable resin agent is coated by spin coating. At this time, coating is performed to a thickness of about 5 μm.

As in the first experimental example, a monomer, acrylate or methacrylate monomer is desirable for the resin agent. For example, commercially available acrylate-based Nippon Steel Chemical's V-2400PET is available. Further, as the resin agent, it is also possible to use the acrylate-based ultraviolet-curable resin (V-2400PET of Nippon Steel Chemical Co., Ltd.) dissolved in ethylene glycol monoethyl ether acetate to about 20%.

Thereafter, a pressure of about 0.001 kg / mm ² is applied from both sides to the two substrates (semiconductor substrate and transfer mold) coated with these resins. Then, for photopolymerization, ultraviolet light of 350 nm is irradiated for 100 hours.
Irradiate 0 mJ / cm ² . As a result, a sample including the microstructure on which the transfer die is formed is formed.

As described above, by previously spreading the resin material by spin coating to form the resin layer on both of the two substrates (the semiconductor substrate and the transfer type), the same as in the first experimental example, The pressing force can be considerably reduced to about 0.001 kg / mm ² . Therefore, even in the second experiment, the size can be reduced by about one digit compared to the method shown in FIG. Thereby, the pressure to be applied can be easily balanced, and there is no distortion of the transfer mold at the time of pressing, the film thickness can be easily controlled, and the yield is improved.

Also, in the sample (fine structure) manufactured by this method, the variation in the film thickness is 1 μm or less, and the example described above with reference to FIG. In the method of putting the resin and pressing it later,
Whereas the variation in the film thickness is about 10 μm, the manufacturing method of this example can reduce the variation in the formed film thickness by one digit or more.

As described above, according to the manufacturing method of the present invention, in the preparatory step, the resin material is previously coated by spin coating, so that a resin layer having a uniform and accurate film thickness can be formed. In this state, the transfer mold can be pressed. For this reason, when transferring the mold, it is only necessary to apply pressure with a small force, and it is easy to balance the application of pressure, and the variation at the time of manufacture accompanying this is within the submicron order. At the same time, not only the accuracy of each chip or microstructure in a group unit is improved, but also the dimensional variation of the whole wafer is extremely reduced, so that the yield is improved.

Therefore, according to the present invention, high-quality devices can be mass-produced at low cost. Therefore, it is very useful as a future micro replica technology. In particular, in the method of manufacturing a microstructure according to the present invention, the variation in the thickness direction, which was a weak point of the micro-replica technology, can be reduced to the order of submicron, and the image display device using the evanescent light exemplified above. This is an important technology for mass-producing.

In the above description, the present invention has been described based on an example in which a resin agent is coated by spin coating in the preparation step. However, the present invention is not limited to this, and flexographic printing is also used as a method for controlling the film thickness. Is a well-established technology, and it is possible to form a resin layer having a uniform thickness in advance by coating a resin agent by flexographic printing.
A manufacturing method using flexographic printing is also included in the present invention.

In the above description, an electrostatic actuator and an optical switching element in which optical elements are vertically stacked on a semiconductor substrate are described as an example. However, other electromechanical effects such as a piezo effect can be used. The present invention can also be applied to an optical switching device that constructs an optical element on an actuator that has been used. Further, an object to be switched is not limited to an evanescent wave, and an optical element array exhibiting a switching action in another optical system can be similarly manufactured. Of course, the switching target is not limited to light, but may be another medium such as a fluid. Further, as described above, not only the combination of the actuator and the switching, but also other microstructures using a micro replica technology, such as a device in which an optical element is directly stacked on a semiconductor substrate, a surface emitting laser substrate, and the like. The present invention can also be applied to

[0062]

As described above, in the method of manufacturing a microstructure according to the present invention, when a microstructure is formed by die transfer, a resin agent is spin-coated or flexographically printed on a substrate in advance. A preparation step for forming a layer is provided. Therefore, the resin can be evenly spread on the substrate before the transfer mold is pressed. in this way,
In the manufacturing method of the present invention, a highly reliable method such as spin coating or flexographic printing as a technique for determining the dimensional accuracy in the thickness direction is combined with a molding method by die transfer capable of forming a fine shape with high accuracy. The structure can be manufactured with high precision. The effect is that the resin needs to be pressed and stretched by the transfer mold,
It also shows that the pressure value of the mold transfer can be reduced by one to two digits. For this reason, in the manufacturing method of the present invention, the yield of the fine structure is improved because there is no distortion of the transfer mold at the time of pressurization and the film thickness can be easily controlled. Also, by spreading the resin agent on the substrate in advance,
Since unevenness of the surface (unevenness in pressure) can be prevented, a uniform film thickness can be accurately controlled in this respect, and the yield can be improved.

Therefore, according to the present invention, it is possible to manufacture a more accurate micro device or micro machine using the micro replica technology. In particular, when mass-producing chip-shaped microstructures from a wafer, the use of the manufacturing method according to the present invention can greatly improve the yield and can be provided at low cost.

In the above-described video display device using evanescent light, an accuracy of about sub-micron is required in the thickness direction. However, the production method of the present invention makes it possible to mass-produce chips satisfying such requirements. It becomes possible.
Therefore, the present invention is suitable for actually manufacturing and mass-producing an image display device using evanescent light.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a manufacturing process of an optical switching element using evanescent light, and is a diagram illustrating a state where a first electrode layer is formed on a semiconductor substrate.

FIG. 2 is a view illustrating a manufacturing process of the optical switching element, and is a view illustrating a state in which a first sacrificial layer is formed on a first electrode layer.

FIG. 3 is a view illustrating a process of manufacturing an actuator on a semiconductor substrate, and is a view illustrating a state in which a second electrode layer (spring layer) is formed on a first sacrificial layer.

FIG. 4 is a diagram showing a state in which a second sacrificial layer is formed on a second electrode layer on a semiconductor substrate.

FIG. 5 is a view showing a state of a preparation step of applying a resin on a substrate by spin coating according to the present invention.

6 is a view showing a state in which a transfer mold is applied to the spin-coated resin layer shown in FIG. 5 and pressure is applied.

FIG. 7 is a diagram showing a state where a support structure is formed by mold transfer.

FIG. 8 is a diagram showing a state in which a micro prism is formed by mold transfer.

FIG. 9 is a diagram showing a state in which the optical element manufactured in FIG. 8 is separated.

10 (a) to 10 (d) are views schematically showing an experimental example performed according to a manufacturing method provided with a preliminary step according to the present invention.

FIG. 11 is a diagram showing an outline of a video display device using evanescent light.

12 (a) to 12 (c) are schematic views showing a state in which a resin is sandwiched between a substrate and a transfer mold, pressure is applied, and mold transfer is performed.

[Explanation of symbols]

 Reference Signs List 1 light guide plate (light guide) 2 incident light 3 resin layer (optical element) 4 microprism 6 actuator 7 upper electrode and spring structure 8 lower electrode 9 anchor 10 optical switching element 11 post (post) 12 driving space 20 semiconductor substrate Reference Signs List 25 actuator array layer 26 optical element array layer 32, 34 sacrificial layer 35, 36 resin 35a, 36a resin layer 47 space for separation 50 optical switching device 55 video display device 61, 62 transfer type (micro replica)

Claims (14)

[Claims] 1. A step of forming a microstructure by mold transfer in which a resin layer is sandwiched between a plurality of substrates and pressurized, and before that, a resin agent is spin-coated or flexographic-printed on at least one of the substrates. And a preparation step of forming the resin layer by performing the method. 2. The method according to claim 1, wherein one of the substrates is:
A method for producing a microstructure, wherein the method is a semiconductor substrate on which an integrated circuit is formed, and the other is the transfer type for transferring a shape. 3. The method of manufacturing a microstructure according to claim 1, wherein the step of molding the microstructure includes a step of curing the resin agent with light while the substrate is pressed. 4. The method according to claim 1, wherein in the preparing step,
A method for producing a fine structure, comprising dissolving the resin agent in an organic solvent and performing the spin coating. 5. The method according to claim 1, wherein the microstructure is a micro-optical element array. 6. The micro-actuator according to claim 1, further comprising an actuator array in which micro-actuators for driving a switching unit formed in the step of forming the microstructure are arranged in an array. A method for manufacturing a fine structure, comprising forming the resin layer on an array. 7. The method according to claim 6, wherein another structural layer on which a sacrificial layer for manufacturing the microactuator is laminated is formed in advance, and in the preparing step, the resin is overlapped with the other structural layer. A method for producing a microstructure, comprising forming a layer. 8. The microstructure according to claim 6, wherein, in the step of forming the microstructure, a micro-optical element array in which micro-optical elements serving as the switching units are arranged in an array. Manufacturing method. 9. The method according to claim 8, wherein the micro-optical element switches a evanescent light. 10. The method according to claim 6, wherein the microactuator is an electrostatic actuator. 11. A step of manufacturing, on a substrate, an actuator array in which microactuators are arranged in an array, and micro-optical elements are arranged in an array from a resin layer using a transfer mold on the actuator array. Forming a micro-optical element array; and, before forming the micro-optical element array, spin-coating or flexographic printing a resin agent on at least one of the actuator and the transfer mold. And a preparation step of forming the resin layer thereby. 12. The method according to claim 11, wherein the micro-actuator is an electrostatic actuator, and the micro-optical element array performs optical switching by evanescent light. 13. The method of manufacturing an image display device according to claim 11, wherein the step of molding the micro-optical element array includes a step of curing the resin agent with light while pressing the actuator and the transfer mold. . 14. The method according to claim 11, wherein, in the preparing step, the resin agent is dissolved in an organic solvent to perform the spin coating.