JP4359054B2 - Planar electromagnetic actuator and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a planar electromagnetic actuator and a manufacturing method thereof.
[0002]
[Prior art]
Typical planar actuators include those used in laser beam scanning systems and the like. Currently, in order to reduce the size of the planar electromagnetic actuator, a method of manufacturing using a semiconductor device manufacturing process has been developed. (See Patent Document 1)
[0003]
In addition, a planar electrostatic actuator using electrostatic force has been devised as a driving method. (See Patent Document 2)
[0004]
FIGS. 1A and 1B show the configuration of a tip portion of a conventional planar type electromagnetic actuator in which a coil portion is formed on the periphery of a mirror portion. FIG. 1A is a top view, FIG. 1B is a bottom view, and FIG. It is AA 'sectional drawing.
[0005]
First, a movable plate 2 and torsion bars 3 a and 3 b that pivotally support the movable plate 2 with respect to the substrate 1 are integrally formed on the substrate 1. A mirror portion 4 is formed at the center of the surface of the movable plate 2, and a coil portion 5 is formed at the peripheral portion thereof, and an electromagnetic driving force is generated in the coil portion 5 to drive the movable plate 2.
[0006]
FIG. 2 is a diagram showing a manufacturing process of a chip portion according to the above-described conventional planar type electromagnetic actuator. Hereinafter, with reference to FIG. 2, a manufacturing process of a chip portion according to a conventional planar electromagnetic actuator will be described.
Step (a) Oxide Film Formation Step: Both front and back surfaces of a 500 μm thick silicon laminated substrate 6 are thermally oxidized to form silicon oxide films 7a and 7b. The silicon bonded substrate is commonly called an SOI substrate, and is composed of, for example, active layer silicon 8 (100 μm), intermediate layer silicon oxide film 9 (1 μm), and support substrate silicon 10 (400 μm).
Step (b) Coil pattern forming step: Each pattern of the coil 11b, the insulating film 12, the coil 11a, and the protective film 13 is sequentially laminated on the surface of the silicon oxide film 7a by photolithography.
Step (c) Oxide Film Removal Step 1: A portion of the silicon oxide film 7a excluding the active layer silicon 8 end and the movable plate forming portion is removed by etching.
Step (d) Active Layer Removal Step: The active layer silicon 8 exposed by the etching in the step (c) is removed by etching.
Step (e) Intermediate layer removal step 1: The intermediate layer silicon oxide film 9 exposed by the etching in the step (d) is removed by etching.
Step (f) Oxide Film Removal Step 2: The portion of the silicon oxide film 7b excluding the end portion of the support substrate silicon 10 is removed by etching.
Step (g) Support substrate removing step: The support substrate silicon 10 exposed by the etching in the step (f) is removed by etching.
Step (h) Intermediate layer removal step 2: The intermediate layer silicon oxide film 9 exposed by the etching in the step (g) and the silicon oxide film 7b at the end of the support substrate silicon 10 are removed by etching.
Step (i) Mirror deposition film formation step: A mirror deposition film 14 made of gold (Au) or the like is formed on the mirror formation portion on the surface of the silicon oxide film 7a by vacuum deposition or sputtering.
Through the above-described processes, chip portions related to the conventional planar type electromagnetic actuator are manufactured. Usually, like a semiconductor element, a large number of chips are simultaneously formed on a large wafer and divided into individual pieces after completion. In addition, description and illustration of the resist pattern forming process and the like are omitted (hereinafter, similarly omitted).
[0007]
Here, as a problem of the conventional planar type electromagnetic actuator in which the coil part is formed on the peripheral part of the movable part described above, the coil, the insulating film, and the protective film formed on the coil part have tensile stress. As a result, the mirror part warps, and the mirror part also warps.
[0008]
This is because a silicon oxide film formed by thermally oxidizing the surface of an SOI substrate has a compressive stress opposite to the tensile stress, but the tensile stress of a coil or the like is stronger, resulting in the warpage. That is why.
[0009]
Therefore, in order to solve the above problem, a planar type electromagnetic actuator has been devised in which a stress film for suppressing warpage is formed on the movable plate. (See Patent Document 3)
[0010]
Also, in the planar electrostatic actuator, the mirror warpage caused by various factors is a problem, and a planar electrostatic actuator that attempts to solve the above problem by the same means as described above has been devised. ing. (See Patent Document 4)
[0011]
[Patent Document 1]
Japanese Patent No. 0722314 (page 3-4, Fig. 1-2)
[Patent Document 2]
Japanese Patent No. 03361975 (pages 4-6, 5-8)
[Patent Document 3]
Japanese Patent Laid-Open No. 2002-296517 (pages 4-5 and 5-7)
[Patent Document 4]
JP 2002-267996 A (page 3-4, FIG. 1-2)
[0012]
[Problems to be solved by the invention]
However, conventional planar actuators such as the electromagnetic drive type that attempt to eliminate the warp of the mirror portion require a new step of forming a stress film.
[0013]
In view of the above problems, the present invention provides a planar electromagnetic actuator having a coil part at the peripheral part of the movable part and a mirror part at the center part, and a stress film for suppressing warpage is newly formed. It is another object of the present invention to provide a planar type electromagnetic actuator capable of suppressing warpage occurring in the mirror part by adjusting the film thickness of the mirror deposition film itself formed on the mirror part, and a method for manufacturing the same.
[0014]
[Means for Solving the Problems]
A movable portion and a torsion bar that pivotally supports the movable portion with respect to the substrate; a mirror portion is provided at a central portion of the movable portion; a driving coil portion is provided at a peripheral portion of the movable portion; In the planar type electromagnetic actuator having a structure in which a driving force is applied to the mirror, the mirror deposition films are formed in different thicknesses on the front and back side mirror formation portions of the mirror portion , and the mirror deposition films The planar electromagnetic actuator is formed so that the stress of the thinner mirror deposition film and the stress generated in the coil portion are canceled by the stress of the thicker mirror deposition film .
[0015]
An oxide film forming step of thermally oxidizing both front and back surfaces of a silicon bonded substrate (SOI substrate) to form front and back double-sided silicon oxide films; a coil, an insulating film, and A coil pattern forming step of laminating each pattern of the protective film; a first oxide film removing step of removing a surface side mirror forming portion of the surface side silicon oxide film by etching; and a movable plate forming portion of the surface side silicon oxide film And a second oxide film removing step for removing the portion excluding the active layer silicon end portion by etching, and an active layer removing step for removing the active layer silicon exposed by the etching in the second oxide film removing step by etching, the first intermediate layer removing for removing the intermediate layer silicon oxide layer exposed by the etching of the active layer removing step by etching Etching and extent, and the third oxide film removal step of removing a portion except for the support substrate silicon end of the back side silicon oxide film by etching, the supporting substrate silicon exposed by the etching of the third oxide film removing step A supporting substrate removing step that is removed by etching, a second intermediate layer removing step that removes the intermediate silicon oxide film exposed by the etching in the supporting substrate removing step by etching, the first oxide film removing step, and the second intermediate layer. Forming a mirror deposition film having a different thickness on the front and back side mirror forming portions of the active layer silicon exposed by the etching in the layer removal process, wherein the mirror deposition films are thick. Due to the stress of the mirror deposition film, the stress of the mirror deposition film with the smaller film thickness and the stress generated by the lamination of each pattern A mirror deposited film forming step of forming as killing, the method of manufacturing a planar type electromagnetic actuator having a.
[0016]
An oxide film forming step of thermally oxidizing both front and back surfaces of a silicon (Si) substrate to form a front and back double-sided silicon oxide film, and a portion of the back-side silicon oxide film excluding a silicon substrate end portion is removed by etching . A first oxide film removing step, a first silicon substrate removing step of removing the silicon substrate exposed by the etching in the first oxide film removing step by etching while leaving the thickness of the movable plate, and the surface side silicon oxide A coil pattern forming step of laminating each pattern of a coil, an insulating film, and a protective film on the film by photolithography, and a second oxide film removing step of removing the surface side mirror forming portion of the surface side silicon oxide film by etching When the third oxide film removal for removing portions other than the movable plate forming portion and the silicon substrate end portion of the front side silicon oxide film by etching Degree and a second silicon substrate removing step of removing the silicon substrate exposed by the etching of the third oxide film removal process, on both sides side mirror forming part of the silicon substrate, different film mirrors deposited film having a stress In the process of forming a thick film, these mirror deposited films are offset by the stress of the thinner mirror deposited film and the stress generated by the lamination of the respective patterns by the stress of the thicker mirror deposited film. a mirror deposited film forming process of forming to, a method of manufacturing a planar type electromagnetic actuator having a.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
In the present invention, the true stress of the thin film is used to solve the problem. First, the stress of the thin film will be described. When a thin film is formed on a substrate, the substrate or the thin film may bend if the substrate is thin, and cracks or peeling may be observed on the thin film if the substrate is thick. This is because stress exists inside the thin film. And the internal stress of this thin film necessarily exists in the thin film formed by the vacuum evaporation method, sputtering method, etc., and is divided roughly into a thermal stress and a true stress. The thermal stress is a stress that is generated due to a difference in coefficient of thermal expansion between the substrate and the thin film when the temperature of the substrate and the thin film is lowered in the thin film formation process. On the other hand, as for the true stress, the cause of this occurrence has been proposed by various thin film formation processes, such as those caused by volume changes and those caused by surface or interface effects.
[0018]
Such a stress acting between the thin film and the substrate is called a tensile (tensile) stress or a compressive stress depending on whether it is tensile or compressive through a cross section perpendicular to the substrate surface. FIG. 11 is a diagram showing the stress of the thin film. As shown in FIG. 11A, the film surface is concave as shown in FIG. 11A and the tensile stress is when the thin film is pulled from the substrate. When the surface is convex and the thin film is pressed from the substrate, it is compressive stress.
[0019]
In the vacuum deposition method, whether the thin film exhibits tensile stress or compressive stress is almost determined by the material of the thin film and the substrate, and it does not change unless it is very special. However, when a thin film is formed by sputtering, a large change occurs depending on the conditions. For example, when the discharge gas pressure of sputtering is high, most of the metal thin film exhibits a tensile stress, but as the sputtering gas pressure decreases, the tensile stress decreases and finally exhibits a compressive stress. Several reasons have been made for this reason, but the detailed explanation is omitted. As described above, the true stress is caused by many causes, and the properties greatly differ depending on the formation conditions even if the thin film is the same material.
[0020]
In the present invention, in accordance with the contents described above, the implementation is performed based on the idea that the stress is brought close to zero as a whole by superimposing a thin film having a tensile stress and a thin film having a compressive stress. For example, if the thin film formed on the substrate has a tensile stress and warps as a whole, a thin film having another tensile stress or compressive stress is formed on the appropriate side surface so as to cancel it. By doing so, it is possible to cancel each other's stress and suppress warping.
[0021]
FIG. 3 is a cross-sectional view of the tip portion of the planar electromagnetic actuator according to the first embodiment of the present invention. However, the drawings used in the present specification make the structure easy to understand and are not to scale. In the first embodiment of the present invention and the second embodiment to be described later, the mirror part deformation factor generated in the coil part is prevented from being transmitted to the mirror part between the coil part and the mirror part. An example in which the present invention is applied to a planar electromagnetic actuator having a configuration having a boundary will be described. Hereinafter, with reference to FIG. 3, a chip portion according to the planar electromagnetic actuator according to the first embodiment of the present invention will be described.
[0022]
The active layer silicon 8 which is a movable plate has a thickness of 100 μm and a size of 14 × 10 mm. In the first embodiment of the present invention, chromium (Cr) or the like is used for the mirror deposition films 15 and 16 formed on the mirror portion and has a tensile stress. The mirror deposition film 16 on the front surface side is 0.01 μm, the mirror deposition film 15 on the back surface side is 0.15 μm, and the mirror deposition film 15 is formed thicker than the mirror deposition film 16. Are both 5 × 6 mm. The surface-side silicon oxide film 7a has a thickness of 1 μm, and the coils 11a and 11b both have a width of 40 μm, a thickness of 2 μm, a coil interval of 10 μm, and a turn number of 15. The insulating film 12 and the protective film 13 are both 2 μm thick and use polyimide. The width of the coil portion 17 is 800 μm, and the lengths of the torsion bars 3a and 3b are both 1000 μm.
[0023]
The feature of this configuration is that, as described above, the mirror deposition films 15 and 16 made of chromium (Cr) having tensile stress are formed in the mirror portion, and the mirror deposition film 15 is formed thicker than the mirror deposition film 16. It is that. As a result, the tensile stress due to the mirror deposition film 15 dominates in the entire mirror part, and as a result, it cancels out the stress from the coil part and suppresses the warp of the mirror part. Here, although the mirror deposition films 15 and 16 are made of chromium (Cr) or the like, any film may be used as long as it has a tensile stress and does not affect the physical properties of other thin films. No particular mention is made of the substance. That is, if a high effect as a reflection mirror is expected, a material having excellent reflectivity may be selected.
[0024]
Next, with reference to FIG. 4, the manufacturing process of the chip | tip part which concerns on the planar type electromagnetic actuator which is 1st Embodiment of this invention of Claim 1 is demonstrated.
Step (a) Oxide Film Formation Step: Both front and back surfaces of the SOI substrate 6 are thermally oxidized to form silicon oxide films 7a and 7b.
Step (b) Coil pattern forming step: Each pattern of the coil 11b, the insulating film 12, the coil 11a, and the protective film 13 is sequentially laminated on the surface of the silicon oxide film 7a by photolithography.
Step (c) Oxide Film Removal Step 1: The surface side mirror forming portion of the silicon oxide film 7a is removed by etching.
Step (d) Oxide Film Removal Step 2: The portion of the silicon oxide film 7a excluding the active layer silicon 8 end and the movable plate forming portion is removed by etching.
Step (e) Active layer removal step: The active layer silicon 8 exposed by the etching in the step (d) is removed by etching.
Step (f) Intermediate Layer Removal Step 1: The intermediate layer silicon oxide film 9 exposed by the etching in the step (e) is removed by etching.
Step (g) Oxide Film Removal Step 3: The portion of the silicon oxide film 7b excluding the end portion of the support substrate silicon 10 is removed by etching.
Step (h) Support Substrate Removal Step: The support substrate silicon 10 exposed by the etching in the step (g) is removed by etching.
Step (i) Intermediate layer removal step 2: The intermediate layer silicon oxide film 9 exposed by the etching in the step (h) and the silicon oxide film 7b at the end of the support substrate silicon 10 are removed by etching.
Step (j) Mirror deposition film forming step: Mirror deposition films 15 and 16 made of chromium (Cr) or the like are vacuum-deposited on the rear surface side mirror formation portion on the back surface of the active layer silicon 8 and the front surface side mirror formation portion. Alternatively, each is formed by a sputtering method. Here, the mirror deposition film 15 has a tensile stress like the mirror deposition film 16 and is deposited thicker than the mirror deposition film 16.
The reason why the silicon oxide film 7a is removed following the steps (c) and (d) is because it is convenient for the next active layer silicon removal step (e). You may go.
[0025]
FIG. 5 is a cross-sectional view of a tip portion of a planar electromagnetic actuator according to a second embodiment of the present invention. The feature of this configuration is that, contrary to the case of the first embodiment, mirror deposition films 17 and 18 made of chromium (Cr) having compressive stress are formed. Furthermore, since the mirror deposition film 18 is formed to be thicker than the mirror deposition film 17, the compressive stress due to the mirror deposition film 18 dominates in the entire mirror section, and as a result, the mirror section deforms from the coil section. The stress, which is a factor, cancels out and warping of the mirror part is suppressed. Here, the mirror deposition films 17 and 18 may be any material as long as they have a compressive stress and do not affect the physical properties of other thin films, and the materials thereof are not particularly mentioned.
[0026]
Next, with reference to FIG. 6, the manufacturing process of the chip | tip part which concerns on the planar type electromagnetic actuator which is 2nd Embodiment of this invention of Claim 1 is demonstrated. In this case, since the basic manufacturing process is the same as that of the first embodiment, only a part of the manufacturing process will be described.
Steps (a) to (h): Omission step (i) Intermediate layer removal step 2: The intermediate layer silicon oxide film 9 exposed by the etching in the step (h) is removed by etching.
Step (j) Mirror deposition film formation step: Mirror deposition films 17 and 18 made of chromium (Cr) or the like are deposited on the back surface side mirror formation portion on the back surface of the active layer silicon 8 and the front surface side mirror formation portion by vacuum evaporation, Alternatively, each is formed by a sputtering method. Here, the mirror deposition film 18 has a compressive stress like the mirror deposition film 17 and is deposited thicker than the mirror deposition film 17.
[0027]
FIG. 7 is a cross-sectional view showing a tip portion of a planar type electromagnetic actuator according to a third embodiment of the present invention. A feature is that a silicon (Si) substrate is used as the substrate constituting the chip portion, instead of the SOI substrate used in the first and second embodiments. Note that the size of the chip portion, the basic configuration, the stress action by the deposited film, and the like are the same as those in the first and second embodiments, and the description thereof will be omitted (hereinafter the same is omitted).
[0028]
FIG. 8 is a diagram showing a manufacturing process of a chip portion related to the above-described planar type electromagnetic actuator. Hereinafter, the manufacturing process will be described with reference to FIG.
Step (a) Oxide Film Formation Step: The front and back surfaces of the silicon substrate 19 are thermally oxidized to form silicon oxide films 20a and 20b.
Step (b) Oxide Film Removal Step 1: A portion of the silicon oxide film 20b excluding the end of the silicon substrate 19 is removed by etching.
Step (c) Silicon Substrate Removal Step 1: The silicon substrate 19 exposed by the etching in the step (b) is removed by etching while leaving a thickness necessary for forming the movable plate.
Step (d) Coil pattern forming step: Each pattern of the coil 11b, the insulating film 12, the coil 11a, and the protective film 13 is sequentially laminated on the surface of the silicon oxide film 20a by photolithography.
Step (e) Oxide Film Removal Step 2: The surface side mirror forming portion of the silicon oxide film 20a is removed by etching.
Step (f) Oxide Film Removal Step 3: The portion of the silicon oxide film 20a excluding the end portion of the silicon substrate 19 and the movable plate forming portion is removed by etching.
Step (g) Silicon Substrate Removal Step 2: The silicon substrate 19 exposed by the etching in the step (f) is removed by etching.
Step (h) Mirror deposition film forming step: Mirror deposition films 21 and 22 made of chromium (Cr) or the like are deposited on the back side mirror forming part on the back side of the silicon substrate 19 and the front side mirror forming part on the front surface by vacuum evaporation, or Each is formed by sputtering. Here, the mirror deposition film 21 has a tensile stress like the mirror deposition film 22 and is deposited thicker than the mirror deposition film 22.
[0029]
FIG. 9 is a cross-sectional view showing a tip portion of a planar type electromagnetic actuator according to a fourth embodiment of the present invention. As a feature, the silicon substrate is used as the substrate constituting the chip portion as in the third embodiment.
[0030]
FIG. 10 is a diagram showing a manufacturing process of a chip portion according to the planar type electromagnetic actuator according to the fourth embodiment of the present invention. Hereinafter, the manufacturing process will be described with reference to FIG. In this case, since the basic manufacturing process is the same as that of the third embodiment, only a part of the manufacturing process will be described.
Steps (a) to (f): Omission step (g) Silicon substrate removal step 2: The silicon substrate 19 exposed by the etching in the step (f) is removed by etching.
Step (h) Mirror deposition film forming step: Mirror deposition films 23 and 24 made of chromium (Cr) or the like are applied to the rear surface side mirror formation part on the rear surface of the silicon substrate 19 and the front surface side mirror formation part by a vacuum evaporation method, or Each is formed by sputtering. Here, the mirror deposition film 24 has a compressive stress like the mirror deposition film 23 and is deposited thicker than the mirror deposition film 23.
[0031]
FIG. 12 is a diagram showing the definition of warpage, where d is the amount of warpage. Warpage of about 0.6 μm occurred on the surface of the mirror portion of the conventional planar electromagnetic actuator formed under the same conditions as in the embodiment of the present invention. In general, the flatness (warping amount) of the mirror part is desirably λ / 4 or less. However, in the embodiment of the present invention, the warp can be λ / 4 (0.17 μm) or less. It was. λ is the wavelength of the laser beam, for example, 670 nm for red visible laser beam.
[0032]
Also, as the material of the mirror deposition film, it is conceivable to use gold (Au), aluminum (Al) or the like. However, when aluminum (Al) is used, there is a risk of erosion (oxidation, etc.). A treatment for forming a silicon oxide film or the like as a protective film is required. Any material can be used as long as the problem of warping can be suppressed, as long as the physical properties of other thin films are not affected. A deposited film may be formed.
[0033]
Furthermore, when forming the mirror deposition film, by selecting a material having excellent adhesion to the active layer silicon or the silicon substrate as the base, the adhesion between the thin films is improved and the entire movable plate is warped. Can be relaxed. In addition, even if the deposit (coil, insulating film, protective film) on the surface of the movable plate is thick and the stress exerted on the movable plate is large, or the movable plate is thin and subject to the stress of the deposit, By forming a deposited film having a corresponding stress, warpage can be suppressed, and the degree of design freedom increases.
[0034]
The technology according to the present invention relates to a planar type electromagnetic actuator having a coil part at the peripheral part of the movable part and a mirror part at the center part, but has an electromagnetic drive type and electrostatic drive type having other structures. The present invention can also be applied to planar type actuators. Needless to say, the technique is not limited by the shape of the movable plate.
[0035]
【The invention's effect】
As described above, according to the first aspect of the present invention, the film thickness of the mirror deposition film itself having tensile stress or compressive stress is generated in the coil portion by making the film thickness different from each other on both the front and back sides of the mirror portion . It is possible to suppress the warpage of the mirror part by generating a stress that cancels the stress in the entire mirror part and canceling it with the stress of the coil part. Further, since the mirror deposited film itself has a function as a stress film, it is not necessary to form a new stress film, and the number of steps can be reduced.
[Brief description of the drawings]
FIGS. 1A and 1B are diagrams showing a tip portion of a conventional planar type electromagnetic actuator having a coil portion at a peripheral portion of a movable portion and a mirror portion at a central portion, wherein FIG. 1A is a top view, FIG. It is -A 'sectional drawing.
FIG. 2 is a manufacturing process diagram of a chip portion of a conventional planar type electromagnetic actuator having a coil portion at a peripheral portion of a movable portion and a mirror portion at a central portion. FIG. 3 shows a book in which a mirror deposition film on the back side of the mirror portion is formed thick. AA ′ cross-sectional view of the first embodiment of the invention FIG. 4 is a manufacturing process diagram of the first embodiment of the present invention. FIG. FIG. 6 is a manufacturing process diagram of the second embodiment of the present invention. FIG. 7 is a sectional view of the third embodiment of the present invention in which the mirror deposition film on the back surface side of the mirror portion is formed thick. 8 is a manufacturing process diagram of the third embodiment of the present invention. FIG. 9 is a cross-sectional view taken along the line AA ′ of the fourth embodiment of the present invention in which the mirror deposition film on the mirror surface side is formed thick. Manufacturing process diagram of form Fig. 11 Diagram showing stress of thin film Fig. 12 Diagram showing definition of warpage Explanation】
DESCRIPTION OF SYMBOLS 1 Substrate 2 Movable plate 3a Torsion bar 3b Torsion bar 4 Mirror part 5 Coil part 6 Silicon bonded substrate (SOI substrate)
7a Silicon oxide film 7b Silicon oxide film 8 Active layer silicon 9 Intermediate layer silicon oxide film 10 Support substrate silicon 11a Coil 11b Coil 12 Insulating film 13 Protective film 14 Mirror deposited film 15 Mirror deposited film (tensile stress)
16 Mirror deposited film (tensile stress)
17 Mirror deposited film (compressive stress)
18 Mirror deposited film (compressive stress)
19 Silicon substrate 20a Silicon oxide film 20b Silicon oxide film 21 Mirror deposited film (tensile stress)
22 Mirror deposited film (tensile stress)
23 Mirror deposited film (compressive stress)
24 Mirror deposited film (compressive stress)

Claims (3)

A movable portion and a torsion bar that pivotally supports the movable portion with respect to the substrate; a mirror portion is provided at a central portion of the movable portion; a driving coil portion is provided at a peripheral portion of the movable portion; In the planar type electromagnetic actuator configured to drive by applying a driving force to
Mirror deposition films are formed with different film thicknesses on the front and back side mirror forming parts of the mirror part ,
In addition, these mirror deposition films are formed so that the stress of the mirror deposition film having a smaller thickness and the stress generated in the coil portion are offset by the stress of the mirror deposition film having a larger thickness. Planar type electromagnetic actuator. An oxide film forming step of thermally oxidizing both front and back surfaces of a silicon bonded substrate (SOI substrate) to form both front and back side silicon oxide films;
A coil pattern forming step of laminating each pattern of a coil, an insulating film, and a protective film by photolithography on the surface-side silicon oxide film;
A first oxide film removing step of removing a surface side mirror forming portion of the surface side silicon oxide film by etching;
A second oxide film removing step of removing a portion excluding the movable plate forming portion and the active layer silicon end portion of the surface side silicon oxide film by etching;
An active layer removing step of removing the active layer silicon exposed by the etching in the second oxide film removing step by etching;
A first intermediate layer removing step of removing the intermediate silicon oxide film exposed by the etching of the active layer removing step by etching;
A third oxide film removing step of removing a portion of the back side silicon oxide film excluding a support substrate silicon edge by etching;
A supporting substrate removing step of removing the supporting substrate silicon exposed by the etching in the third oxide film removing step by etching;
A second intermediate layer removing step of removing the intermediate layer silicon oxide film exposed by the etching in the supporting substrate removing step by etching;
This is a step of forming mirror deposited films having stresses with different thicknesses on the front and back side mirror forming portions of the active layer silicon exposed by the etching in the first oxide film removing step and the second intermediate layer removing step. Te, mirror deposited to form these mirrors deposited film, so as to cancel the stress and the stress generated by the lamination of the patterns of the mirror deposited film stress by the membrane thickness thinner the mirror deposited film more large thickness A film forming step ;
A planar electromagnetic actuator manufacturing method characterized by comprising: An oxide film forming step of thermally oxidizing both front and back surfaces of a silicon (Si) substrate to form front and back side silicon oxide films;
A first oxide film removing step of removing a portion of the back side silicon oxide film excluding a silicon substrate end by etching;
A first silicon substrate removing step of removing the silicon substrate exposed by the etching in the first oxide film removing step by etching while leaving the thickness of the movable plate;
A coil pattern forming step of laminating each pattern of a coil, an insulating film, and a protective film by photolithography on the surface-side silicon oxide film;
A second oxide film removing step of removing the surface side mirror forming portion of the surface side silicon oxide film by etching;
A third oxide film removing step of removing a portion excluding the movable plate forming portion and the silicon substrate end portion of the surface side silicon oxide film by etching;
A second silicon substrate removing step of removing the silicon substrate exposed by the etching of the third oxide film removing step ;
A process of forming mirror deposition films having stresses at different film thicknesses on the front and back side mirror forming portions of the silicon substrate, and these mirror deposition films are formed according to the stress of the thicker mirror deposition film. A mirror deposition film forming step of forming the mirror deposition film so as to cancel out the stress of the thinner mirror deposition film and the stress generated by the lamination of each pattern ;
A planar electromagnetic actuator manufacturing method characterized by comprising:

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