JP2000131630A - Production of mirror device, mirror device and optical pickup device including the same as well as optical recording and reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To impart sufficient rigidity to a displacing mirror section and to impart reflectivity of >=95%, more preferably >=98% thereto. SOLUTION: This mirror device has a first substrate 1 which is formed with first electrodes 7 and the mirror section 16 which is fixed at one end to at least the first substrate 1 and has a second electrode 17 formed on the opposite surface holding a gap with the first electrodes 7 and a mirror film 13 formed on the opposite surface of the second electrode 17 and is constituted to displace the mirror section 16 by the electrostatic force generated when the voltage difference is impressed between the first electrodes 7 and the second electrode 17. The mirror film 13 is so formed as to have a mirror metallic film containing one kind of any among silver, gold and aluminum, a dielectric film formed on the mirror metallic film, an SiO2 film of, for example, 100 nm in thickness and an Si2N4 of, for example, 75 nm in thickness on the SiO2 film.

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 mirror device, a mirror device, an optical pickup device and an optical recording / reproducing device having the same, and more particularly, to a method for applying a voltage difference between opposing electrodes. The present invention relates to a method of manufacturing a mirror device having a configuration in which a mirror section is displaced by generated electrostatic force, a mirror device, an optical pickup device including the same, and an optical recording / reproducing device.

[0002]

2. Description of the Related Art Mirror devices for driving micromirrors using electrostatic force or electromagnetic force have been developed by micromachining technology called micromachining. For example, Proc. SPIE, vol1150p6 (1989) “Deformable mirr
or spatial light modulators ”by LJHornbeck et al., with a thickness of 10 μm to 20 μm square thickness 0.3 μm
A mirror section made of aluminum having a thickness of about 0.5 μm;
There has been reported a micromirror device in which the mirror portion is supported on a substrate by an elastic body called a support. In this technique, a voltage difference is applied to electrodes arranged opposite to each other with a predetermined space therebetween, and the mirror is displaced by the generated electrostatic force. A mirror device which functions as a deflecting element by tilting a mirror surface constituting a mirror portion is used as a tracking device of an optical pickup device provided for an optical recording medium, which is capable of reproducing only, recording only, or recording and reproducing. Is possible.

For example, the optical and mechanical characteristics required for a mirror device as a tracking device of an optical pickup device include the surface roughness of a mirror film and the parallelism with respect to the main surface of a fixed-side substrate, as well as the incident beam diameter. On the other hand, it is particularly important to have a sufficient mirror film area and a high reflectance. If the mirror film area is 10 μm to 20 μm square and the film thickness is 0.3 μm to 0.5 μm as in a conventional mirror device, the rigidity is sufficient, and there is a possibility that warpage or the like will occur and the parallelism will be reduced. Did not. When the mirror film thickness was 0.3 μm to 0.5 μm, a film having good surface properties could be formed by a usual sputtering method or vapor deposition method. However, when the mirror film area is as large as 100 μm square or more and the operating frequency of the displacing mirror portion is as high as 1 kHz or more, the rigidity is insufficient with the conventional mirror film thickness of 0.3 μm to 0.5 μm. Yes, it is necessary to make the mirror film thicker. However, many man-hours are required to form a mirror film having a thickness of 5 μm or more using a normal sputtering method or a vapor deposition method. Further, stress or the like occurs in the mirror film during film formation due to the temperature rise, and it has been difficult to obtain a mirror film having a satisfactory surface roughness.

By the way, a process of forming a mirror film with gold by increasing the film forming speed by combining three types of plating, copper plating, nickel plating and gold plating, is also conceivable. However, in this case, there is a problem in equipment that requires a plating apparatus for each plating process. Furthermore, it has been difficult to obtain a reflectance of 95% or more, preferably 98% or more, using a conventional mirror film made of aluminum or gold.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a mirror device manufacturing method, a mirror device, and a mirror device in which a displaceable mirror portion has sufficient rigidity and a reflectance of 95% or more, preferably 98% or more. An object of the present invention is to provide an optical pickup device and an optical recording / reproducing device having the same.

[0006]

In order to solve the above-mentioned problems, a method of manufacturing a mirror device according to the present invention comprises:
At least a step of forming a concave portion on a first substrate made of, for example, glass, a step of forming a first electrode on the bottom surface of the concave portion, and a step of forming a second electrode on a second substrate made of, for example, silicon Forming a first electrode and a second electrode
A step of bonding the first substrate and the second substrate by, for example, heating and fusing with the electrodes facing each other, and forming a mirror metal film on the surface of the second substrate opposite to the surface on which the second electrode is formed. Forming a dielectric film on the mirror metal film;
Patterning a first substrate, a mirror metal film, and a dielectric film to form a mirror portion supported by a second electrode having at least one end fixed to the first substrate. The step of forming the mirror metal film includes the step of forming a film containing any one of silver, gold, and aluminum, and the step of forming the dielectric film includes, for example, SiO _{2 having a} thickness of 100 nm. Forming a film,
On this SiO ₂ film, for example, 75 nm thick Si ₃
A step of forming an N ₄ thin film.

In the method of manufacturing a mirror device according to a second aspect of the present invention, at least a step of forming a first electrode and a lead electrode on a substrate made of, for example, glass, and a step of forming the first electrode and a lead electrode on the substrate Forming a first photoresist film covering the electrode; and selectively removing the first photoresist film formed on the extraction electrode near the first electrode, thereby removing the first photoresist film. Forming a column electrically connected to the extraction electrode on the extracted extraction electrode, polishing the first photoresist film and the column to the same plane, and covering the first photoresist film and the column. Forming a second electrode film, forming a second photoresist film on the second electrode, and forming a second photoresist film on the second electrode on the first electrode. Select membrane Forming a mirror base electrically connected to the second electrode on the second electrode from which the second photoresist film has been removed, and removing the second photoresist film Forming a mirror metal film over the second electrode and the mirror base; forming a dielectric film on the mirror metal film; forming a mirror metal film and a dielectric film on the support and the mirror base; A step of selectively removing the mirror metal film, the dielectric film and the second electrode formed on other portions while leaving the body film and the second electrode extending from the support to the mirror base; Removing the photoresist film and forming a mirror portion supported by a second electrode having at least one end fixed to the support, wherein the step of forming the mirror metal film comprises silver. Of gold, aluminum And a step of forming a film containing any one of Chi, forming a dielectric film, for example film thickness to form a SiO ₂ film of 100 nm,
On this SiO ₂ film, for example, 75 nm thick Si ₃
A step of forming an N ₄ thin film.

In the mirror device according to the third aspect of the present invention, the substrate on which the first electrode is formed and the second electrode formed on an opposing surface at least one end of which is fixed to the substrate and sandwiches a gap with the first electrode. And a mirror portion having a mirror film formed on the surface opposite to the opposing surface, and applies a voltage difference between the first electrode and the second electrode and generates the mirror portion by an electrostatic force generated. Is displaced, the mirror film includes a mirror metal film containing any one of silver, gold, and aluminum, and a dielectric film formed on the mirror metal film, for example, a SiO ₂ film having a thickness of 100 nm. And this S
On the iO ₂ film, for example, a Si ₃ N ₄ film having a thickness of 75 nm is provided.

According to a fourth aspect of the present invention, at least a semiconductor laser as a light source and light emitted from the semiconductor laser are guided to an objective lens, and the semiconductor laser is formed through the objective lens of the light emitted from the semiconductor laser. An optical pickup device having a mirror device for controlling a light spot in a tracking direction of an optical recording medium, the mirror device comprising: a substrate on which a first electrode is formed; at least one end fixed to the substrate; A second electrode formed on an opposing surface sandwiching the gap, and a mirror portion having a mirror film formed on the opposite surface of the first electrode and the opposing surface sandwiching the gap, wherein the mirror film is formed of silver. A mirror metal film containing any one of aluminum, gold, and aluminum, and a dielectric film formed on the mirror metal film, for example, having a film thickness of 10
It is characterized by having a SiO ₂ film having a thickness of 0 nm and a Si ₃ N ₄ film having a thickness of, for example, 75 nm on the SiO ₂ film.

In the optical recording / reproducing apparatus according to a fifth aspect of the present invention, at least a semiconductor laser as a light source and light emitted from the semiconductor laser are guided to an objective lens, and light emitted from the semiconductor laser is formed through the objective lens. An optical pickup device having a mirror device for controlling a light spot to be recorded in a tracking direction of an optical recording medium, and a feeding device for controlling the optical pickup device in a tracking direction, wherein the mirror device is a first device. And a second electrode formed on an opposing surface sandwiching a gap with the first electrode, and a second electrode formed on an opposing surface sandwiching a gap with the first electrode, and an opposite surface sandwiching the gap with the first electrode. And a mirror portion having a mirror film formed thereon, wherein the mirror film is a mirror metal film containing any one of silver, gold, and aluminum. , The dielectric film formed on the mirror metal film, for example, a SiO ₂ film having a film thickness of 100 nm, the SiO ₂ onto the film, for example film thickness of 75 nm Si ₃ N ₄
It is characterized by having a film.

The operation of the above means will be described below. In the method for manufacturing a mirror device of the present invention, the mirror film area and rigidity of the conventional displaceable mirror portion are both large and the reflectivity is increased by the dielectric film formed on the mirror metal film without requiring many man-hours. It is possible to provide a large mirror device. If this mirror device is used as a tracking device of an optical pickup device, it is possible to obtain good optical characteristics that reflect light emitted from a semiconductor laser as a light source and light reflected from an optical recording medium with high efficiency. In addition, an increase in the rigidity of the mirror section enables an increase in the bandwidth of the tracking servo, and the provision of an optical pickup device and an optical recording / reproducing device corresponding to an optical recording medium with a high density and a large capacity.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention provides a method for manufacturing a mirror device in which a mirror portion is displaced by an electrostatic force generated while applying a voltage difference between electrodes arranged opposite to each other, a mirror device, and an optical recording device having the same. The present invention can be applied to an optical pickup device that performs tracking servo on a medium and an optical recording / reproducing device. The optical recording / reproducing apparatus of the present invention includes a reproduction-only apparatus that performs only reproduction, a recording-only apparatus that performs only recording, and an apparatus that can perform both recording and reproduction. Hereinafter, a process for manufacturing the mirror device of the present invention will be described with reference to FIGS.

Embodiment 1 This embodiment is an example in which a mirror device is manufactured by using two substrates and bonding them together. For example, one substrate is made of glass, and the other substrate is made of glass. This is an example in which silicon is used. Hereinafter, a schematic process explanatory diagram showing a process sequence of preparing a substrate made of glass first, subsequently preparing a substrate made of silicon, and subsequently bonding these two substrates to complete a mirror device. 1 and FIG. 2 subsequent to FIG. Note that the present embodiment is not limited to the following process order. For example, the steps may be such that the production of a substrate made of silicon is firstly performed, the production of a substrate made of glass is later performed, and these two substrates are later bonded to complete a mirror device. Alternatively, the steps of manufacturing a substrate made of glass and a substrate made of silicon may be performed in parallel, and the two substrates may be later bonded to complete a mirror device.

First, as shown in FIG. 1A, on one main surface of a first substrate 1 made of glass having high-precision surface roughness and flatness, for example, a heat-resistant tempered glass. After the first photoresist film 2 is formed on the entire surface, patterning is performed to remove the first photoresist film 2 at a portion where the first electrode and the extraction electrode are to be formed later.

Next, as shown in FIG. 1B, the portion where the first photoresist film 2 is removed by, for example, RIE (Reactive Ion Etching) or the like is reduced to, for example, 5 μm.
To form a recess 3 in which the first electrode is formed and a recess 4 in which the extraction electrode is formed.

Next, after the entire first photoresist film 2 is removed, as shown in FIG. 1C, the concave portions 3 of the first substrate 1 are formed by using, for example, an evaporation method or a sputtering method.
A first electrode precursor 5 having a thickness of 0.1 μm to 2 μm is formed on the entire surface on which the surface 4 is formed. It is preferable that the first electrode precursor 5 has a small electric resistance.
Can be gold, copper, silver, chromium, tungsten, tantalum, molybdenum, nickel, titanium and the like. Then, patterning is performed to leave the second photoresist film 6 on the entire surface of the first electrode precursor 5. Then, after etching the first electrode precursor 5 using the second photoresist film 6 as a mask, the entire second photoresist film 6 is removed. Through these steps, the first electrode 7 composed of the four divided electrodes 7 a, 7 b, 7 c, 7 d is formed in the recess 3, and the first electrode 7 is formed in the recess 4.
An extraction electrode 8 composed of the two electrodes 8a, 8b, 8c, 8d is formed.

Next, the production of the second substrate 9 made of silicon is started. 2 (a) used here.
Substrate 9 is an example in which p-type or n-type impurities are doped in advance so that the electric resistance is sufficiently small. When a substrate having a large electric resistance is used,
An electrically equivalent configuration can be obtained by appropriately doping impurities or depositing a metal film. As shown in FIG. 2A, a second substrate 9 having high-precision surface roughness and flatness is placed on a surface of the first substrate 1 on which the concave portions 3 and 4 are formed by heat, pressure or electric field. Are bonded together by applying.

Next, as shown in FIG.
The surface opposite to the bonding surface of the substrate 9 is mechanically polished, for example, so that the thickness of the second substrate 9 becomes 10 μm or less, and the surface roughness Ra of the polished surface is made approximately 10 nm or less. Then, as shown in FIG. 2D, the second substrate 9
A mirror metal film 10 is formed on the entire polished surface. The material forming the mirror metal film 10 is selected according to the wavelength of the incident light and the desired reflectance. For example, wavelength 650n
In the case of obtaining a reflectance of 95% for light of m, it can be obtained by forming silver or an alloy containing silver by a sputtering method. At this time, in order to improve the adhesion of the mirror metal film 10 to the second substrate 9, an underlayer made of a metal such as chromium may be formed in advance. Further, an SiO ₂ film 11 having a thickness of, for example, 100 nm is formed on the mirror metal film 10, and a Si film having a thickness of, for example, 75 nm is formed on the SiO ₂ film 11.
By forming the ₃ N ₄ film 12, it is possible to obtain a mirror film 13 having a reflectivity of 98% or more for light having a wavelength of 650 nm.

The mirror metal film 10 is made of, in addition to silver or an alloy containing silver, gold, an alloy containing gold, aluminum,
It may be made of an alloy containing aluminum. When the mirror metal film 10 is made of an aluminum single-layer film, it is effective to form a dielectric layer on the aluminum single-layer film in order to improve the reflectance. For example, a SiO ₂ film 11 having a thickness of 100 nm is formed on an aluminum single-layer film, and a S nm film having a thickness of, for example, 75 nm is formed on the SiO ₂ film 11.
If the i ₃ N ₄ film 12 is formed, a reflectance of 96.5% can be obtained for light having a wavelength of 640 nm. Note that the wavelength is shorter than 640 nm, for example, 400 nm to 50 nm.
Since the reflectance of gold in light in a wavelength band of 0 nm is lower than that in silver and aluminum, silver, aluminum or an alloy containing these is desirable for light in such a band.

Next, as shown in FIG. 2E, after a third photoresist film 14 is formed on the entire surface of the mirror film 13, the third photoresist film 14 on the concave portion 3 is left to be patterned. I do. Next, the Si ₃ N ₄ film 12 and the SiO ₂ film 11, which are dielectrics, are etched using the patterned third photoresist film 14 as a mask. At this time, selective etching is performed so that the mirror metal film 10 is not etched even when the etching proceeds. For example, when the mirror metal film 10 is made of aluminum, CF ₄ or SF _{6 is used.}
Such as RIE in a gas containing no chlorine. Then, after the etching is completed, the third photoresist film 14 is removed.

Next, as shown in FIG.
Of the photoresist film 15 of the mirror metal film 10 and Si
₃ N ₄ film 12 was formed on the entire surface, shown in partial (Figure 3 and portion elastic member 19 for supporting the mirror portion 16 and the mirror unit 16 shown in FIG. 4 are formed) and after 3 constituting the mirror Patterning is performed so that the fourth photoresist film 15 remains in a portion to be the second electrode terminal 18.
Next, the patterned fourth photoresist film 1
Using the mask 5 as a mask, the mirror metal film 10 is etched. Next, the second substrate 9 is etched using the patterned fourth photoresist film 15 or the patterned mirror metal film 10 as a mask. At this time, the thickness of the second substrate 9 to be etched is substantially 1
The width of the elastic body 19 supporting the mirror portion 16 is desirably smaller than 0 μm, and is, for example, 0.5 μm to 5 μm. Therefore, since the aspect ratio at the time of etching, that is, the so-called aspect ratio is 1 or more, it is necessary to perform anisotropic etching. For example, when the mirror metal film 10 and the four electrodes 7a, 7b, 7c, 7d forming the first electrode 7 and the four electrodes 8a, 8b, 8c, 8d forming the extraction electrode 8 are made of aluminum, CF _{4 is used.} , RIE or the like to the SF ₆ or XeF ₂ and the reactive gas is effective.

Next, as shown in FIG.
After the photoresist film 15 is completely removed, washed and dried, the mirror metal film 10 is electrically connected to the second electrode terminal 18 formed on the second substrate 9 to form the mirror portion 16. If wiring is performed so that a voltage difference can be applied between the second electrode 17 and the first electrode 7 composed of the four electrodes 7a, 7b, 7c, 7d divided into the concave portions 3, As shown in the schematic sectional view of FIG. 3 and the schematic plan view of FIG. 4, a mirror device having both ends supported by the elastic body 19 and functioning as a deflection element is completed. Although FIG. 4 shows the mirror section 16 having a circular shape, the present invention is not limited to this.

The operation of the above-described mirror device functioning as a deflecting element will now be described with reference to FIGS. An electrode 8a constituting the extraction electrode 8,
By applying a voltage difference between the electrodes 7a and 7b constituting the first electrode 7 and the second electrode 17 via the second electrode 8b, the elastic member 1
An electrostatic force that rotates the mirror unit 16 clockwise in FIG. 3 around the rotation center 9 acts to deflect the reflected light in the A direction. Conversely, the electrode 7 constituting the first electrode 7 via the electrodes 8c and 8d constituting the extraction electrode 8
When a voltage difference is applied between c and 7d and the second electrode 17, an electrostatic force acts to rotate the mirror 16 in the counterclockwise direction in FIG. Can be deflected in the B direction. Also, the first electrode 7
No voltage difference is applied between the first electrode 7 and the four electrodes 7a, 7b, 7
When the same voltage difference is applied between c and 7 d and the second electrode 17, the mirror section 16 is set in a neutral state by the elastic body 19.

When this mirror device is used as a tracking device of an optical pickup device, it is important that the position of the mirror unit 16 in the direction perpendicular to the mirror surface is important if the incident light entering the mirror unit 16 is a parallel light flux. No. However, when the light beam incident on the mirror unit 16 is convergent light or divergent light, the position in the direction perpendicular to the mirror surface of the mirror unit 16 is precisely adjusted to focus on the information recording surface of the optical recording medium. It is necessary to deflect while maintaining In such a case, it is desirable to apply a certain amount of bias voltage to the electrodes 7a, 7b, 7c, 7d constituting the first electrode 7.

The reason why the four electrodes 7a, 7b, 7c and 7d to be divided as the first electrode 7 are formed in the recess 3 will be described below. In order to obtain a large deflection angle with a low applied voltage, the four electrodes 7a and 7
It is advantageous to increase the area of b, 7c, 7d. However, when the electrodes 7a and 7b constituting the first electrode 7 are integrated and the electrodes 7c and 7d are integrated to increase the area of each electrode, the mirror 16 is formed on the mirror 16 by the inclination of the mirror 16. There is a possibility that the second electrode 17 and the first electrode 7 that have been brought into contact with each other may be electrically short-circuited. The second electrode 1 formed on the mirror section 16
The distance between the outer edge of the first electrode 7 and the electrode 7a or 7c constituting the first electrode 7 becomes smaller with the inclination of the mirror section 16,
The electrostatic force acting on the mirror section 16 also gradually increases. For these reasons, the mirror surface, which is originally desired to be flat during operation, may be distorted. Therefore, in the present embodiment, even when the mirror portion 16 is greatly inclined, the outer edge of the mirror portion 16 is in contact with the electrodes between the electrodes 7a and 7b or between the electrodes 7c and 7d. To avoid an electrical short circuit caused by contact between the first electrode 7 and the second electrode 17. Also,
By controlling the electric field applied to the divided electrodes 7a and 7b or the electrodes 7c and 7d for each electrode, the mirror unit 1 is controlled.
With the inclination of 6, the control of the electrostatic force acting on the mirror section 16 is also possible.

In this embodiment, in addition to the above-described case, a mirror film is formed substantially at the center of the second electrode 17 as shown in the schematic external perspective view of FIG. Both ends of the second electrode 17 extending from the position are supported by the first substrate 1. Then, the first substrate formed on the first substrate 1
Of the second electrode 17 on the side opposite to the side on which the first substrate 1 is supported by the second electrode 17, a mirror device having a function as a deflection element in which the mirror section 16 is displaced in the direction of the arrow in FIG. Is also possible. Although not shown, the patterns of the first electrode 7 and the second electrode 17 are
A mirror device having a function as a phase modulation element in which 6 moves parallel to the direction of the first substrate 1 can also be manufactured through the same steps as described above. In this embodiment, a plurality of mirror devices can be manufactured at one time. In this case, a step of cutting into chips is required for each mirror device, and a liquid such as wax or a photoresist is injected before cutting so that the mirror portion 16 is not damaged by vibration at the time of cutting, and solidified by heating or the like. In some cases, it is also necessary to remove the solidified substance with a solvent after cutting and cutting.
Further, four electrodes 7a, 7b constituting the first electrode 7,
7c, 7d, four electrodes 8 constituting the extraction electrode 8
The wiring of a, 8b, 8c, 8d and the second electrode 17
For example, it can be pulled out by a conductive adhesive or a wire bonder.

Embodiment 2 This embodiment is an example in which a mirror device is manufactured from one substrate. This will be described with reference to FIGS. 6A to 6C, which are schematic process explanatory views of the mirror device of the example referred to in FIG. 5 of the first embodiment, and FIGS.

First, as shown in FIG. 6A, the entire surface of one main surface of a substrate 20 made of silicon, glass, or the like is formed of, for example, a thin film of nickel and gold each formed by sputtering. After forming the metal film 21, the first photoresist film 2 is formed on the entire surface of the metal film 21.
To form Then, patterning is performed to remove the first photoresist film 2 other than the portions that become the first electrode 7 and the extraction electrode 8 later. The portion where the first photoresist film 2 is removed differs between a case where a mirror device functioning as a phase modulation element is manufactured and a case where a mirror device functioning as a deflection element is manufactured.

Next, as shown in FIG.
After the photoresist film 2 is patterned, etching is performed to form a first electrode 7 and a lead electrode 8, and thereafter, the entire second photoresist film 6 is removed. Then, after forming the second photoresist film 6 covering the substrate 20, the first electrode 7, and the extraction electrode 8, the support 22 supporting the second electrode 17 on the extraction electrode 8 and later.
Then, patterning is performed to remove the second photoresist film 6 in the portion to be formed.

Next, as shown in FIG. 6C, for example, nickel is deposited on the extraction electrode 8 from which the second photoresist film 6 has been removed by, for example, electrolytic plating.
Is grown over the top surface of the photoresist film 6 of FIG.
To form

Next, as shown in FIG. 6D, the columns 22 and the second photoresist film 6 are mechanically polished, for example, to finish the columns 22 to a predetermined height.

Next, as shown in FIG.
The second electrode 17 is formed by covering the photoresist film 6 and the pillars 22 with, for example, nickel by electroless plating or sputtering.

Next, as shown in FIG.
After the third photoresist film 14 is formed on the entire surface of the first electrode 17, patterning for removing the third photoresist film 14 on the first electrode 7 is performed, and the third photoresist film 14 is removed. The mirror base 23 is formed by pattern-plating nickel, for example, on the portion thus formed. When forming the mirror base 23, a thin nickel film may be formed in advance as a base layer by a sputtering method or the like on the portion of the second electrode 17 from which the third photoresist film 14 has been removed.

Next, as shown in FIG.
After the photoresist film 14 and the mirror base 23 are mechanically polished, and the surface of the mirror base 23 is finished to a highly accurate flatness and surface roughness, for example, the surface roughness Ra of about 10 nm or less, the third photo The resist film 14 is entirely removed. The thickness of the mirror base 23 is determined based on the rigidity required for the mirror device.

Next, as shown in FIG.
The mirror metal film 10 on which, for example, silver is deposited by a sputtering method is formed so as to cover the electrode 17 and the mirror base 23. The material forming the mirror metal film 10 is selected according to the wavelength of the incident light and the desired reflectance. For example,
In the case of obtaining a reflectance of 95% with respect to light having a wavelength of 650 nm, the reflectance can be obtained, for example, by forming silver or an alloy containing silver by a sputtering method. Further, in order to increase the reflectance of the mirror metal film 10, an SiO ₂ film 11 having a thickness of, for example, 100 nm is formed on the mirror metal film 10, and a thickness of, for example, 75 nm is formed on the SiO ₂ film 11.
When the Si ₃ N ₄ film 12 is formed, a mirror film 13 having a reflectance of 98% or more with respect to light having a wavelength of 650 nm can be obtained. Then, by covering the mirror film 13, the fourth
After the photoresist film 15 is formed, patterning is performed to leave the fourth photoresist film 15 on the columns 22 and the mirror base 23.

The mirror metal film 10 may be made of gold, an alloy containing gold, or aluminum in addition to silver or an alloy containing silver. When the mirror metal film 10 is made of an aluminum single-layer film, it is effective to form a dielectric layer on the aluminum single-layer film in order to improve the reflectance. For example, a 100 nm-thick Si
An O ₂ film 11 is formed, and a film thickness of 75 is formed on the SiO ₂ film 11.
If the Si ₃ N ₄ film 12 having a wavelength of 640 nm is formed,
95% reflectivity with respect to the light, and the SiO ₂ film 11 and the Si ₃ N ₄ film 12 function as a protective film against an aqueous solution of ethylenediaminepyrocatechol used in a later step. In this case, the SiO ₂ film 1
The total thickness of the film 1 and the Si ₃ N ₄ film 12 is 175 nm, and if the thickness is about this, rapid processing can be performed by etching such as ion milling.

When the mirror metal film 10 is made of gold or an alloy containing gold, the mirror metal film 10 is stable to an aqueous solution of ethylene / diamine / pyrocatechol, and it is not necessary to form a protective film. However, similarly, a 100 nm thick SiO ₂ film 11 is formed on a thin film of gold or an alloy containing gold, and a 75 nm thick Si ₃ N ₄ film 12 is formed on the SiO ₂ film 11.
Is formed, 96.5% for light having a wavelength of 640 nm
Can be obtained. The wavelength is 640 nm.
Since the reflectance of gold in light in the blue to green wavelength band of, for example, 400 nm to 500 nm is lower than that of silver and aluminum, silver, aluminum, or an alloy thereof is preferable for light in such a band. .

Next, as shown in FIG.
Film 1 other than the portion where the photoresist film 15 is formed
The third and second electrodes 17 are removed by etching.

Next, when all of the second, third, and fourth photoresist films 6, 14, and 15 are removed, as shown in FIG. 17
Thus, a mirror device having the mirror film 13 formed substantially at the center of the second electrode 17 and the first electrode 7 formed between the columns 22 of the substrate 20 can be obtained.
Then, after finishing by washing and drying, although not shown, if wiring of the first electrode 7 and the second electrode 17 is performed, for example, as shown in the schematic external perspective view of FIG. A mirror device having a function as a deflection element is completed. In the case described above, it is possible to manufacture a plurality of mirror devices at one time. In this case, a step of cutting into chips is required for each mirror device, and a liquid such as wax or a photoresist is injected before cutting so that the mirror portion 16 is not damaged by vibration at the time of cutting, and solidified by heating or the like. In some cases, it is also necessary to remove the solidified substance with a solvent after cutting and cutting. Further, the wiring of the first electrode 7 and the second electrode 17 can be drawn out to the outside by, for example, a conductive adhesive or a wire bonder.

In the present embodiment, in addition to the cases described above, although not shown, the patterns of the first electrode 7 and the second electrode 17 are configured such that the mirror base 23 moves in the direction of the substrate 20 in parallel. It is also possible to manufacture a mirror device that functions as a phase modulation element through the same steps as described above. Further, it is also possible to manufacture the mirror device of the embodiment 1 shown in FIGS. 3 and 4.

The mirror device functioning as a deflecting element manufactured by the method of manufacturing a mirror device shown in the first and second embodiments is used as a tracking device of an optical pickup device provided in an optical recording / reproducing apparatus. It is possible. The optical pickup device in this case has a configuration in which light emitted from a semiconductor laser as a light source is guided to an objective lens via a mirror device. That is, a voltage difference signal based on the tracking error signal is applied to the first electrode 7 and the second electrode 17 constituting the mirror device, and the mirror section 16 is tilted according to the voltage difference. Due to the inclination of the mirror section 16, the light spot formed by the objective lens moves in the tracking direction of the optical recording medium, and the tracking servo is performed.
Further, the mirror device having the function of the deflecting element and having the mirror film 13 with high reflectivity and the objective lens are integrally sought in the tracking direction of the optical recording medium by the feeding means constituted by, for example, a linear motor. In the optical recording / reproducing apparatus having the configuration, the size and weight can be reduced and the thickness can be reduced, and the speed of seeking can be increased.

[0042]

According to the method of manufacturing the mirror device of the present invention, the mirror area and rigidity of the conventional movable mirror section are both large and formed on the mirror metal film without requiring many man-hours. The dielectric film can provide a mirror device having a high reflectance. In an optical pickup device using this mirror device as a tracking device, it is possible to obtain good optical characteristics that reflect light emitted from a semiconductor laser as a light source and light reflected from an optical recording medium with high efficiency. In addition, an increase in the rigidity of the mirror section enables an increase in the bandwidth of the tracking servo, and the provision of an optical pickup device and an optical recording / reproducing device corresponding to a high-density and large-capacity optical recording medium.

[Brief description of the drawings]

FIG. 1 is a schematic process explanatory view illustrating a process for manufacturing a mirror device according to a first embodiment of the present invention.

FIG. 2 is a schematic process explanatory view following FIG. 1 for explaining a manufacturing process of the mirror device of the first embodiment of the present invention.

FIG. 3 is a schematic cross-sectional view of the mirror device manufactured through a manufacturing process of the mirror device according to the first embodiment of the present invention.

FIG. 4 is a schematic plan view of the mirror device manufactured through a manufacturing process of the mirror device according to the first embodiment of the present invention.

FIG. 5 is a schematic external perspective view of another example of the mirror device manufactured through the manufacturing process of the mirror device according to the first embodiment of the present invention.

FIG. 6 is a schematic process explanatory view illustrating a process of manufacturing a mirror device according to Embodiment 2 of the present invention.

FIG. 7 is a schematic process explanatory view illustrating a manufacturing step of the mirror device according to the second embodiment of the present invention, following FIG. 6;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... 1st board | substrate, 2 ... 1st photoresist film, 3 and 4
... recesses, 5 ... first electrode precursor, 6 ... second photoresist film, 7 ... first electrodes, 7a, 7b, 7c, 7d ... electrodes, 8 ... extraction electrodes, 8a, 8b, 8c, 8d ... Electrode, 9 ... Second substrate, 10 ... Mirror metal film, 11 ... Si
O ₂ film, 12 ... Si ₃ N ₄ film, 13 ... mirror film, 14 ...
Third photoresist film, 15: fourth photoresist film, 16: mirror portion, 17: second electrode, 18: second electrode terminal, 19: elastic body, 20: substrate, 21: metal film,
22 ... pillar, 23 ... mirror base

Claims (5)

[Claims] At least a step of forming a recess in a first substrate; a step of forming a first electrode on a bottom surface of the recess; a step of forming a second electrode on a second substrate; A step in which a first electrode and the second electrode are opposed to each other, and the first substrate and the second substrate are bonded to each other; and a step of bonding the second substrate to a surface opposite to the second electrode forming surface. Forming a mirror metal film; forming a dielectric film on the mirror metal film; patterning the first substrate, the mirror metal film and the dielectric film, and forming at least the first substrate Forming a mirror portion supported by the second electrode having one end fixed thereto, wherein the step of forming the mirror metal film is performed by any one of silver, gold, and aluminum. Process to form a film containing A method of manufacturing a mirror device, wherein the step of forming the dielectric film includes a step of forming a SiO ₂ film and a step of forming a Si ₃ N ₄ film on the SiO ₂ film. 2. a step of forming at least a first electrode and a lead electrode on a substrate; a step of forming a first photoresist film covering the first electrode and the lead electrode; The first photoresist film formed on the extraction electrode in the vicinity of the first electrode is selectively removed, and the extraction electrode is electrically connected to the extraction electrode on which the first photoresist film has been removed. Forming a pillar connected to the first photoresist film and the pillar in the same plane; covering the first photoresist film and the pillar,
Forming a second electrode; forming a second photoresist film on the second electrode; and forming the second photoresist film on the second electrode on the first electrode. Selectively removing the photoresist film, and forming a mirror base electrically connected to the second electrode on the second electrode from which the second photoresist film has been removed; Removing a second photoresist film; forming a mirror metal film covering the second electrode and the mirror base; forming a dielectric film on the mirror metal film; The mirror metal film and the dielectric film formed on the mirror base and the mirror metal film formed on the other portion while leaving the second electrode extending from the support to the mirror base. , The dielectric film and the A mirror that includes a step of selectively removing the second electrode and a step of removing the first photoresist film and forming a mirror portion supported by the second electrode and having at least one end fixed to the support. The device manufacturing method, wherein the step of forming the mirror metal film includes a step of forming a film containing any one of silver, gold, and aluminum, and the step of forming the dielectric film includes: A method for manufacturing a mirror device, comprising: forming an SiO ₂ film; and forming a Si ₃ N ₄ film on the SiO ₂ film. 3. A substrate on which a first electrode is formed; a second electrode formed at least on one end of the substrate, the second electrode being formed on an opposing surface sandwiching a gap with the first electrode; And a mirror portion having a mirror film formed on the opposite surface. The mirror portion is displaced by an electrostatic force generated while applying a voltage difference between the first electrode and the second electrode. in the mirror device, the mirror film, silver, gold, a mirror metal layer comprising any one of a aluminum, and the SiO ₂ film formed on the mirror metal layer, is formed on the SiO ₂ film A mirror device comprising: a Si ₃ N ₄ film; 4. At least a semiconductor laser as a light source, and light emitted from the semiconductor laser guided to an objective lens, and a light spot of the emitted light formed through the objective lens is moved in a tracking direction of an optical recording medium. An optical pickup device having a mirror device for controlling the mirror device, wherein the mirror device has a substrate on which a first electrode is formed, and at least one end fixed to the substrate and an opposing surface sandwiching a gap with the first electrode. A mirror portion having a formed second electrode and a mirror film formed on a surface opposite to the facing surface, wherein the mirror film includes any one of silver, gold, and aluminum An optical pick-up comprising: a metal film; a SiO ₂ film formed on the mirror metal film; and a Si ₃ N ₄ film formed on the SiO ₂ film. Up device. 5. At least a semiconductor laser as a light source, and a light emitted from the semiconductor laser guided to an objective lens, and a light spot of the emitted light formed through the objective lens is moved in a tracking direction of an optical recording medium. An optical pickup device having a mirror device that controls the optical pickup device, and a feeding unit that controls the optical pickup device in the tracking direction, wherein the mirror device comprises: a substrate on which a first electrode is formed; A mirror portion having at least one end fixed to the substrate and having a second electrode formed on an opposing surface sandwiching a gap with the first electrode, and a mirror film formed on a surface opposite to the opposing surface; A mirror metal film containing any one of silver, gold, and aluminum; and a mirror film formed on the mirror metal film. The a SiO ₂ film, the optical recording and reproducing apparatus characterized by having an Si ₃ N ₄ film formed on the SiO ₂ film.