JP2001075029A - Manufacture of micromirror - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a micromirror by which the degree of freedom of the selection of each part material is enhanced without causing high temperature heating, whose reliability is excellent and by which the reduction of a cost is attained. SOLUTION: This method has a process to form a sacrificing layer having an aperture part on a base plate 1, the formation process of a mirror base body to form the mirror body 4 connected with the base plate through the aperture part and having the formation surface of a reflection surface on the sacrificing layer by a particulate heaping method, and the process to form the reflection surface by forming a light reflection layer 6 on the formation surface of the reflection surface of a mirror base body and the process to remove the sacrificing layer, and the micromirror is formed of a very small mirror in which the connection part of the mirror base body 4 to the base plate 1 is made as a hinge part 5.

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 micromirror suitable for a display device, for example.

[0002]

2. Description of the Related Art In a display device using micromirrors, micromirrors each having a reflecting surface are supported on a common substrate so as to slightly rotate around a predetermined axis, and are selected in accordance with display information. The mirror is rotated by, for example, an electrostatic force, thereby deflecting the reflected light path of the light from the light source, so as to perform optical switching, and perform optical display according to display information. This display device has attracted attention because it has an advantage that it can improve the quality of an image, for example, there is no color reproduction noise.

As a display device using a micromirror,
For example, U.S. Pat. No. 5,835,256, Journal of the Japan Society for Precision Engineering, Vol. 65, no. 5, 1999, pages 669-672.

[0004]

Various methods have been proposed for manufacturing micromirrors. For example, a sacrificial layer having an opening formed in a predetermined portion is formed on a common substrate, and a mirror substrate constituting each micromirror is formed on the sacrificial layer by low-pressure chemical vapor deposition (LPCVD) or plasma. By forming by the CVD method and then removing the sacrificial layer, each mirror substrate faces a common substrate with an interval corresponding to the thickness of the sacrificial layer, and is described above with respect to this substrate. The sacrifice layer is supported so as to be capable of minute rotation through an opening. Then, a method is adopted in which a mirror-side electrode is formed on the surface of each mirror base, which becomes a reflective layer having conductivity and high light reflectivity.

[0005] However, in the case of the LPCVD method,
At this time, the substrate temperature was 600 ° C. or higher, and plasma C
Also in the VD method, it is heated to about 300 ° C. Therefore, selection of a substrate material constituting a common substrate on which the mirror bases are arranged and formed has restrictions such as heat resistance.

In order to stably and uniformly support these mirror substrates on a common substrate, it is important that no residual stress is generated in the production of the mirror substrates. When the mirror substrate is made of silicon nitride SiN _x , it is necessary to perform film formation while changing the ratio of the source gas of Si and N. There is a problem that the control for obtaining good is complicated.

Further, the surface of the mirror substrate on which the reflection layer is formed is required to be excellent in smoothness, but it is difficult to obtain a sufficiently satisfactory smooth surface by the above-mentioned CVD method.

The present invention solves the above-mentioned problems and achieves a simple method without high-temperature heating, so that the flexibility of selecting materials for each part is large, the reliability is excellent, and the cost is reduced. An object of the present invention is to provide a micromirror manufacturing method which can be achieved.

[0009]

According to the present invention, there is provided a method of manufacturing a micromirror, comprising: forming a sacrificial layer having an opening on a substrate; and connecting the sacrificial layer to the substrate through the opening on the sacrificial layer. Forming a mirror substrate having a surface forming surface by a fine particle deposition method, forming a light reflecting layer on the reflecting surface forming surface of the mirror substrate to form a reflecting surface, and forming a sacrificial layer. And forming a micromirror using a micromirror having a hinge portion as a connecting portion of the mirror base to the substrate.

As described above, in the present invention, the mirror substrate is formed on the sacrificial layer by depositing fine particles, that is, a so-called fine particle or ultrafine particle deposition method. The mirror substrate formed by this fine particle deposition method can be formed with excellent smoothness, so that an optically excellent mirror can be formed. is there.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method for manufacturing a micro mirror according to the present invention will be described. First, an example of a micromirror, for example, a display device obtained by the manufacturing method of the present invention will be described with reference to FIGS. FIG. 1 is a schematic perspective view in which a part of the main part is sectioned, and FIG. 2 is a schematic cross-sectional view of a part thereof. In this example, a transparent substrate 1 made of, for example, a glass substrate, and a substrate (hereinafter referred to as a drive circuit substrate) 2 on which a drive circuit, for example, a CMOS (Complementary Field Effect Transistor) integrated circuit is formed, are provided, for example, via a columnar spacer 3. They are opposed to each other at a required interval.

On the surface of the transparent substrate 1 on the side facing the drive circuit substrate 2, a plurality of, for example, mirror forming portions each having a side of 12 μm in a direction crossing each other, for example, X and Y directions perpendicular to each other. The mirror bases 4 made of a rectangular thin plate having a rectangular shape are supported and arranged to be able to rotate slightly. In the example shown in FIG. 1, each mirror base 4 is formed with a hinge portion 5 on one side corresponding to each other, for example, parallel to the Y direction, thereby enabling minute rotation around the Y axis direction. Will be supported. This rotation is performed by, for example, a first position shown in solid lines in FIG. 2 and opposed to the inner surface of the transparent substrate 1 at a predetermined distance, for example, in parallel, For example, a second position rotated by about 10 ° can be adopted.

In the example shown in FIGS. 1 and 2, a reflecting layer 6 of, for example, an Al layer is formed on the surface of the mirror substrate 4 on the side facing the transparent substrate 1 so that a light reflecting surface having a high light reflectance is formed. On the side opposite to the drive circuit board 2 on the opposite side, a minute mirror M having a mirror-side electrode 7 formed by applying a conductive layer such as an Al layer is formed.

The drive circuit board 2 is made of, for example, a Si semiconductor substrate on which a CMOS (complementary field effect transistor) drive circuit is formed. And this drive circuit board 2
On the main surface on the side facing the transparent substrate 1, opposing electrodes 8 which are electrically independent from each other are formed to face each mirror base M. Then, a required drive voltage is applied to each counter electrode 8 by a drive circuit, and the mirror M is moved from the first position to the second position, for example, by the electrostatic attraction between the electrodes 7 and 8. 2, the reflected light from the light source 9 shown in FIG. 2 is reflected by the reflection surface of the reflection layer 6, and the reflection directions at the first and second positions described above are respectively changed to different directions indicated by a solid line a and a chain line b. Reflection, that is, deflection and light switching are performed to perform a desired display.

[First Embodiment] In this embodiment, as shown in FIG. 1 and FIG.
A reflection surface, that is, a reflection layer 6 is formed on a surface facing the transparent substrate 1, and a mirror side electrode 7 is formed on a surface facing the drive circuit substrate 2.
This is a case where a micromirror having a mirror M formed with a circle is manufactured. An example of this embodiment will be described with reference to perspective views each showing a part of each of the steps in FIGS. However, the manufacturing method of the present invention is not limited to this example.

As shown in FIG. 3, a resin substrate such as a polycarbonate (PC) substrate and a transparent substrate 1 such as a glass substrate are prepared, and an antireflection film (see FIG. 3) is formed on both main surfaces 1a and 1b. (Not shown).

A light shielding portion 10 is formed on one main surface 1a of the transparent substrate 1 in a region facing the entire region where the hinge portion 5 is finally formed. This light shielding part 10
First, for example, an Al layer having a thickness of, for example, 50 nm is first formed on, for example, the entire surface by vapor deposition and sputtering, and pattern etching is performed by photolithography. That is, a required etching resist is formed by applying a photoresist, pattern exposure, and development on the entire surface of the light shielding layer made of Al or the like, and etching the light shielding layer using the etching resist as a mask. To form a desired pattern.

Then, a sacrificial layer 11 having a required thickness, for example, 50
A film is formed to a thickness of 0 nm.

An opening 11W is formed in a portion of the sacrificial layer 11 where the above-described hinge portion is formed on the light shielding portion 10. Therefore, as shown in FIG. 3, for example, a photoresist layer is applied on the entire surface of the sacrifice layer 11, and a required pattern exposure and development process are performed to form a resist layer 12 having an opening 12W.

Using the resist layer 12 as an etching mask, dry etching is performed on the sacrificial layer 11 through the opening 12W, and under the opening 12W, as shown in FIG.
The opening 11W is formed.

The opening 11W thus formed
Is formed in a trapezoidal cross section in which the opening area decreases toward the bottom, that is, toward the light shielding portion 10 side. That is, the opening 1
The inner peripheral side surface of 1W is a tapered surface that gradually projects toward the center of the opening toward the bottom.

The sacrificial layer 11 in which the opening 11W is formed
A mask 13 is formed thereon as shown in FIG. The mask 13 has a pattern opening 13W formed by a pattern of the mirror base 4 including a hinge portion to be finally formed as described with reference to FIGS. 1 and 2 as shown in FIG. It is formed. That is, the mask 13, the opening 13W ₁ of rectangular shape, in this example, formed by the pattern opening portions 13W is formed to have an L-shaped pattern 13W ₂ pairs facing each other on one side. The mask 13 having the pattern opening 13W can be formed by, for example, a so-called photolithography technique in which a photoresist layer is applied over the entire surface, pattern exposure is performed on the photoresist layer, and development processing is performed.

Next, as shown in FIG. 6, a reflective layer 6 of a metal layer having a thickness of, for example, 30 nm is formed on the entire surface including the mask 13 by vapor deposition, sputtering, or the like.

Further, as shown in FIG.
A mirror base layer 14 constituting the mirror base 4 and the hinge part 5 is entirely formed thereon by a fine particle deposition method.
The base layer 14 of the mirror base 4 can be made of a material having excellent thermal conductivity, whether transparent or opaque. This fine particle deposition method is a method called a so-called gas deposition method. In this case, the ultrafine raw material powder of the constituent material itself of the mirror base material layer 14 is mixed with an inert gas, An ultra-fine particle deposition method for forming a film by jetting at a high speed of several hundred m / s. The mirror base layer 14 thus formed is formed on a surface having excellent denseness and excellent mirror smoothness. This is because the ultrafine particles sprayed at a high speed in this way have their kinetic energy changed to heat energy, and the bond between the film-forming surface and the ultrafine particles and between the fine particles is promoted and deposited. Probably.

Then, in this case, while the nozzle 15 and the transparent substrate 1 are relatively shifted, the jetting and deposition of the ultrafine particle material is performed entirely, and this pattern is formed on the sacrificial layer 11 through the pattern opening 13W. The mirror base layer 14 is formed to a required thickness, for example, 500 nm according to the pattern. In this fine particle deposition method, the processing temperature may be room temperature, and does not require any heating.

A nozzle 15 for depositing the ultra fine particles
The constituent material may be ceramics such as stainless steel (SUS), molybdenum (Mo), and zirconia. The opening of the nozzle 15 can be formed by electrical discharge machining when the constituent material has conductivity. For example, when the constituent material is made of a ceramic material,
It is produced by machining before firing. Further, in order to smooth the surface of the nozzle hole, it is desirable to perform a liquid forming process.

Thereafter, as shown in FIG. 8, the mask 13 is removed, and together with the removal of the mask 13, the reflection layer 6 and the mirror base layer 14 formed on the mask are removed, that is, lift-off is performed. In this way, the mirror base 4 having the hinge portions 5 in the pattern corresponding to the pattern openings 13W shown in FIG. 11 is formed. As shown in FIG. 1, the hinge portion 5 in this example is formed with a pair of arm portions 5A and 5B facing each other.
Each end of B is mechanically coupled to the light shielding unit 10, that is, to the transparent substrate 1 through the opening 11W of the sacrificial layer 11, and the mirror base 4 is supported. The arms 5A and 5B of the hinge 5 formed in this manner are connected to the sacrificial layer 11
5A and 5A formed along the tapered surface on the inner surface of the opening 11W of the arm 5A.
B continuously faces the substrate 1 without causing any break in the mirror base 4 and is joined and supported by the substrate 1.

Thereafter, as shown in FIG. 9, the sacrificial layer 11 shown in FIG. 8 is selectively removed.

In this manner, the mirror base 4 is slightly rotated on one side by the twisting of the pair of arms 5A and 5B of the hinge 5 in the so-called cantilevered state by the hinge 5, as shown in FIG. Possible support is provided.

In this state, as shown in FIG. 10, a conductive layer 18 of, for example, Al is deposited on the entire surface to a thickness of, for example, 30 nm. By doing so, the conductive layer 18 of Al or the like becomes
Formed over the mirror base 4 and the hinge part 5,
Further, it is formed over the transparent substrate 1 excluding the shadowed portion of the mirror base 4 including the hinge portion 5. Thus, the mirror-side electrode 7 is formed by the conductive layer 18. Regarding the mirror side electrode 7 as well, since the hinge portion 5 has the tapered portion 5T, no step disconnection occurs.

In this manner, a mirror M having a minute configuration in which the reflection layer 6 and the mirror-side electrode 7 are formed on each surface of the mirror base 4 is formed.

On the other hand, as shown in FIGS. 1 and 2, a drive circuit based on, for example, a CMOS circuit is used to form a drive circuit board 2 based on, for example, a Si semiconductor substrate formed by a known semiconductor integrated circuit manufacturing technique. A counter electrode 8 made of, for example, Al is formed on the drive circuit board 2 so as to face the mirror base 4, and an insulating layer 16 made of, for example, SiN _x (0.5 ≦ x ≦ 1) is formed to cover the counter electrode 8. Further, at a predetermined portion, for example, as shown in FIG. 1, at a position corresponding to a position between the four mirror bases 4, for example, 3.5 μm in height and 300 nm of In on the top surface. For example, the attached columnar spacer 3 is formed.

The drive circuit board 2 having this configuration and the transparent substrate 1 on which the mirror M is formed are opposed to each other via the spacer 3 so that each mirror M and the opposing electrode 8 face each other. By bonding the top In layer, for example, to the inner surface of the transparent substrate 1, the substrates 1 and 2 are bonded in a state where the facing distance is set by the spacer 3, thereby forming a target display device, for example.

In this configuration, a drive circuit applies a required drive voltage to the counter electrode 8 with respect to the mirror-side electrode 7 to generate an electrostatic attraction between the electrodes 7 and 8, thereby selecting the mirror-side electrode 7. For example, the mirror M is rotated from the above-described first position to the second position, and the irradiation light from the light source 9 shown in FIG. Each of the opposite directions at the second position is reflected or deflected in different directions indicated by a solid line a and a chain line b to perform light switching to perform a target display.

As described above, in the manufacturing method of the present invention, the mirror substrate 4 is formed by the ultrafine particle deposition method.
Generation of residual stress is not substantially recognized, and stable operation as a micromirror can be performed. In addition, since the ultrafine particle deposition method can be performed at room temperature without heating the substrate at a high temperature, residual stress can be prevented from being generated in manufacturing the mirror substrate. Further, the transparent substrate 1 is not required to have heat resistance, and the antireflection film is not affected by heat on both surfaces of the transparent substrate 1. Further, as the light shielding portion 10, the above-described Al layer having low heat resistance can be used.

In the above-described embodiment, a configuration in which the reflection layer 6, that is, the mirror surface, and the mirror side electrode 8 are arranged with the mirror base 4 interposed therebetween is obtained. Since it can be made of, for example, SiC having excellent heat conductivity without having the above-described structure, the heat radiation effect can be enhanced through the mirror base 4. Since the temperature rise due to light irradiation can be avoided by heat radiation, there is an advantage that the deformation of the mirror and the shortening of the life due to the temperature rise can be avoided.

Further, the embodiment according to the first embodiment described above.
An example will be described. (Embodiment 1) In this embodiment, the first embodiment
Although the manufacturing method of the embodiment is adopted,
And the transparent substrate 1 is a polycarbonate (PC) substrate
It was constituted by. The sacrificial layer 11 has a thickness of 500 n.
Form a microcrystalline (Si) layer on m
Done. This microcrystalline Si is obtained, for example, by using silane gas as a raw material gas.
Plasma CV set at a low temperature, for example, 60 ° C.
Method D or ECR (Electron Cyclotron Resonanc)
e) It can be formed by a plasma CVD method. This sacrificial layer
Removal of X11, that is, etching is performed using XeF_TwoBy gas
Dry etching. And this
According to dry etching, the lower layer polycarbonate
Sacrificial layer without disturbing transparent substrate 1 by (PC)
Only 11 can be selectively removed. And Mi
The base 4 is made of silicon nitride by the above-described fine particle deposition method.
Con SiN _x(0.5 ≦ x ≦ 2), particle size 10 nm or less
Formed to a thickness of 500 nm by the deposition of fine particles
Was. The reflection layer 6 and the mirror-side electrode 7 are respectively
It was composed of a 30 nm thick Al vapor deposited film.

(Example 2) As the sacrificial layer 11, a low-temperature CV
A method similar to that of Example 1 was used except that polycrystalline Si formed by Method D was used.

(Embodiment 3) In the same manner as in Embodiment 2, but in this case, prior to the formation of the sacrificial layer 11, a protective layer of SiN _x is formed on the transparent substrate over the light shielding portion 10 (see FIG. (Not shown). By providing the protective layer in this manner, the light shielding portion 10 can be more reliably protected by etching the sacrificial layer 11. (Example 4) A method similar to that of Example 2 was used except that the mirror base 4 was formed of silicon carbide SiC having good thermal conductivity.

(Embodiment 5) According to the same method as that of Embodiment 4, in this case, a protective layer (not shown) made of SiN _x was formed to cover the light shielding portion 10 before forming the sacrificial layer 11. (Example 6) The mirror substrate 4 was made of aluminum nitride AlN.
A method similar to that of Example 2 was used, except that it was formed by

(Embodiment 7) According to the same method as that of Embodiment 6, in this case, a protective layer (not shown) made of SiN _x was formed to cover the light shielding portion 10 before forming the sacrificial layer 11.

The above Examples 1 to 7 are examples of the first embodiment, but are not limited to these examples.

In the above-described first embodiment, the manufacturing method in the case where the reflection layer 6, ie, the mirror surface, and the mirror-side electrode 7 are arranged with the mirror base 4 interposed therebetween is exemplified. For example, the present invention can be applied to a case where a micromirror having a mirror structure in which one surface of the mirror base 4 is formed of the same conductive layer serving as the reflection layer 6 and the mirror-side electrode 7 is provided.

[Second Embodiment] An example of this embodiment will be described with reference to a perspective view showing a part of each of the steps in FIGS. Also in this embodiment, as shown in FIG. 12, a transparent substrate 1 in the form of a plane-parallel plate is prepared.

In the same manner as described with reference to FIG. 3, a region, for example, having a thickness of 50 n, is formed on the main surface 1a of the transparent substrate 1 so as to face the entire region where the hinge 5 is finally formed.
The light shielding part 10 is formed by the Al layer of m.

A protective layer 17 having a thickness of, for example, 200 nm is formed on the entire surface of the transparent substrate 1 so as to cover the light shielding portion 10. A sacrifice layer 11 having a required thickness, for example, a thickness of 500 nm is formed thereon.

Then, similarly to the first embodiment, an opening is formed in the sacrificial layer 11 at the portion where the hinge portion on the light shielding portion 10 is formed. For this purpose, a resist layer 12 made of, for example, a photoresist having an opening 12W is formed on the sacrificial layer 11, as described with reference to FIG. Then, using the resist layer 12 as an etching mask, the sacrificial layer 11 is etched through the opening 12W, and the opening shown in FIG. 11W is formed.

The sacrificial layer 11 in which the opening 11W is formed
A mask 13 can be formed thereon in the same manner as in FIG. 5, but in this example, as shown in FIG. 14, a mask prepared separately is provided on the sacrifice layer 11 or above the sacrifice layer 11. 13 is arranged. The mask 13 has a pattern opening 13W formed by the pattern of the mirror base 4 including the hinge portion, as shown in FIG. That is, the mask 13, the opening 13W ₁ of rectangular shape, in this example, formed by the pattern opening portions 13W is formed to have an L-shaped pattern 13W ₂ pairs facing each other on one side.

Next, as shown in FIG. 14, through the mask 13, that is, through the pattern opening 13W.
Mirror substrate layer 1 constituting mirror substrate 4 and hinge portion 5
4 is sprayed and deposited over the entire surface by a fine particle deposition method. In this case, the mirror base material layer 14 is formed of a light-transmitting material to a required thickness, for example, 500 nm in thickness by the same fine particle deposition method as described above. Also in this case, the deposition processing temperature may be room temperature.

Thereafter, as shown in FIG.
Is etched away by an etchant using hydrofluoric acid, for example. At this time, the transparent substrate 1 made of a glass substrate and the light shielding portion 10 made of Al are prevented from being etched by being covered with the protective layer 17.

In this manner, the mirror base 4 having the hinge portions 5 in the pattern corresponding to the pattern openings 13W of the mask 13 is formed by the base layer 14. Also in this case, the hinge portion 5 can be constituted by a pair of arm portions 5A and 5B, each of which has an end portion,
Through the opening 11W of the sacrifice layer 11, the mirror base 4 is mechanically coupled to the transparent substrate 1 via the protective layer 17 and the light shielding section 10, thereby supporting the mirror base 4. The arms 5A and 5B of the hinge 5 formed in this manner are connected to the sacrificial layer 11
5A and 5A formed along the tapered surface on the inner surface of the opening 11W of the arm 5A.
B continuously faces the substrate 1 without causing any break in the mirror base 4 and is joined and supported by the substrate 1.

Thereafter, as shown in FIG.
A conductive layer 18 such as 1 is deposited, for example, to a thickness of 30 nm, for example. In this manner, the conductive layer 18 of Al or the like is formed on the mirror base 4 and the hinge part 5 by forming the conductive layer 18, and further, excluding the shadowed part of the mirror base 4 including the hinge part 5. 1 is formed over. In this way, a configuration in which the reflective layer 6 and the mirror-side electrode 7 of the above-described example are used by the conductive layer 18 is obtained.

Thereafter, as in FIGS. 1 and 2 described above, the drive circuit board 2 is joined to the transparent substrate 1 with the spacer 3 interposed therebetween.

The micromirror thus obtained can also be formed at room temperature without heating the substrate to a high temperature by forming the mirror substrate 4 by the ultrafine particle deposition method. The configuration using a glass substrate is possible without using a substrate, without using various transparent synthetic resin substrates, or using an expensive quartz substrate.

In this embodiment, the number of manufacturing steps can be simplified by using a structure in which the reflection layer and the conductive layer are combined by one conductive layer.

An example according to the second embodiment will be described, but the present invention is not limited to this example.

(Embodiment 8) In this embodiment, the manufacturing method of the above-described second embodiment is adopted. In this embodiment, the transparent substrate 1 is constituted by a glass substrate. The protective layer 17 was a 200-nm-thick SiN _x layer formed by a plasma CVD method. The sacrificial layer 11 is made of silicon oxide, in this example, SiO ₂ at low temperature C.
It was formed by the VD method. The removal of the sacrificial layer 11 was performed using hydrofluoric acid HF. In this case, below the sacrificial layer 11, Si which is not attacked by this etchant is used.
Transparent substrate 1 by 10 and the glass substrate light-shielding portion by the protective layer 17 by N _x is formed is avoided and eroded. The mirror substrate 4 formed by the fine particle deposition method was made of transparent SiN _x .
The conductive layer 18 serving as the reflection layer 6 and the mirror-side electrode 7
Was formed by a 30-nm-thick Al vapor-deposited film as described above.

Example 9 A sacrificial layer 11 of a polycrystalline Si layer was formed by a low-temperature CVD method without forming the protective layer 17 in the same manner as in Example 8. This sacrificial layer 1
Removal of 1, for example, etching can be performed by dry etching using XeF ₂ gas. This dry etching can be performed without disturbing the transparent substrate 1 without providing the protective layer 17.

In each of Examples 1 to 9 in the first and second embodiments described above, the case where an Al layer is used as the reflection layer 6 and the mirror side electrode 7 is not limited to Al. It can be composed of metals, alloys, such as Ag, Pt, Cr, W, and Au, or a multilayer film thereof. Further, the manufacturing method of the present invention is not limited to the above-described embodiments and examples, and various combinations, modifications, and changes can be performed, and the present invention is not limited to the micromirror of the display device. .

[0060]

As described above, in the manufacturing method of the present invention, the mirror substrate is formed by the ultrafine particle deposition method so that the substrate can be formed at room temperature without heating the substrate to a high temperature. Since there is no requirement for heat resistance in the selection of the material for the mirror substrate, the degree of freedom in the selection of the material is increased, and accordingly, for example, optical, mechanical, etc. required according to the use mode, purpose, etc. Since a substrate having physical characteristics or chemical characteristics or an inexpensive substrate can be used, manufacturing costs can be reduced.

In the manufacturing method of the present invention, the mirror substrate is formed by the ultrafine particle deposition method.
In the mirror base formed in this manner, generation of residual stress is not substantially recognized, and stable operation as a micromirror can be performed. In addition, the ultrafine particle deposition method makes it possible to form a mirror substrate having a high density and excellent flatness, so that an optically and mechanically excellent micromirror can be surely manufactured. Can bring many benefits.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view of a main part of an example of a display device using a micromirror obtained by a micromirror manufacturing method according to the present invention.

FIG. 2 is a schematic sectional view of a part of a display device using the micro mirror shown in FIG.

FIG. 3 is a perspective view showing a part of a manufacturing process of a micromirror according to the present invention in a partly sectional view in one manufacturing process.

FIG. 4 is a perspective view showing a part of a manufacturing process of a micromirror according to the present invention in a partly sectional view in one manufacturing process;

FIG. 5 is a perspective view showing a part of a manufacturing process of a micromirror according to the present invention as a partial cross-sectional view in one manufacturing process.

FIG. 6 is a perspective view showing a part of a manufacturing process of a micro mirror according to an embodiment of the present invention as a partial cross-sectional view.

FIG. 7 is a perspective view in which a part of a manufacturing process of an example of a method for manufacturing a micro mirror according to the present invention is partially sectioned;

FIG. 8 is a perspective view showing a part of a manufacturing process of a micromirror according to the present invention in a part of a sectional view in one manufacturing process;

FIG. 9 is a perspective view in which a part of a manufacturing process of an example of a method for manufacturing a micro mirror according to the present invention is partially sectioned;

FIG. 10 is a perspective view showing a part of a cross-sectional view in one manufacturing process of an example of a method for manufacturing a micro mirror according to the present invention.

FIG. 11 is a plan pattern diagram of a mask in the step shown in FIG. 5;

FIG. 12 is a perspective view showing a part of a cross-sectional view in another manufacturing process of another example of the method for manufacturing a micromirror according to the present invention.

FIG. 13 is a perspective view showing a part of a cross-sectional view in one manufacturing process of another example of the method for manufacturing a micromirror according to the present invention.

FIG. 14 is a perspective view showing a part of a cross-sectional view in one manufacturing process of another example of the method for manufacturing a micro mirror according to the present invention.

FIG. 15 is a perspective view showing a part of a cross-sectional view in one manufacturing process of another example of the method for manufacturing a micromirror according to the present invention.

FIG. 16 is a perspective view showing a part of a cross-sectional view in one manufacturing process of another example of the method for manufacturing a micro mirror according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Transparent substrate, 2 ... Drive circuit board, 3 ... Spacer, 4 ... Mirror base, 5 ... Hinge part, 6
..Reflection layer, 7 ... mirror-side electrode, 8 ... counter electrode, 9 ... light source, 10 ... light shielding portion, 11 ... sacrifice layer, 11W ... opening, 12 ... ..Resist layers, 1
2W: opening, 13: mask, 13W: pattern opening, 14: mirror base layer, 15: nozzle, 16: insulating layer, 17: protective layer, 18 ...
Conductive layer

Claims (10)

[Claims] 1. A step of forming a sacrificial layer having an opening on a substrate, and depositing a mirror base having a reflecting surface forming surface on the sacrificial layer, the mirror base being connected to the substrate through the opening and forming a reflective surface. Forming a mirror base formed by a method, forming a light reflection layer on the formation surface of the reflection surface of the mirror base to form a reflection surface, and removing the sacrificial layer, A method for manufacturing a micromirror, comprising forming a mirror with a connecting portion of the mirror base to the substrate as a hinge portion. 2. A step of forming a light shielding portion on a transparent substrate, and forming a sacrificial layer having an opening at a position corresponding to the light shielding portion on the transparent substrate so as to cover the light shielding portion. Forming a mask having a pattern opening corresponding to the finally obtained mirror pattern on the sacrificial layer; and forming the mask on the sacrificial layer through the pattern opening of the mask.
Forming a reflective layer; forming a mirror base on the reflective layer through the opening of the sacrificial layer to the substrate, using the reflective layer as a reflective surface, through a pattern opening of the mask by a fine particle deposition method. And forming a mirror having a hinge portion as a connecting portion of the mirror substrate to the substrate. 3. A step of forming a light shield on a transparent substrate, a step of forming a protective layer on the transparent substrate having the light shield, and a step corresponding to the light shield on the protective layer. Forming a sacrifice layer having an opening at a position where the mirror substrate is connected to the substrate through the opening of the sacrifice layer and has a reflection surface forming surface.
A step of forming a mirror base formed by a fine particle deposition method, a step of forming a reflection layer on a surface of the mirror base on which the reflection surface is formed, and a step of removing the sacrificial layer; A method for manufacturing a micromirror, comprising forming a mirror having a hinge portion as a connecting portion to the micromirror. 4. The method according to claim 1, further comprising a step of bonding a substrate having a drive circuit to a surface of the substrate having the mirror base. 5. The method according to claim 1, wherein the sacrificial layer comprises a microcrystalline layer. 6. The method according to claim 1, wherein the sacrificial layer comprises a silicon oxide layer. 7. The method according to claim 1, wherein the sacrificial layer is made of polycrystalline silicon. 8. The method according to claim 1, wherein the mirror base is made of silicon nitride. 9. The method according to claim 1, wherein the mirror base is made of silicon carbide. 10. The method according to claim 1, wherein the mirror base is made of aluminum nitride.