KR100209947B1 - Thin film lightpath modulation device - Google Patents

Abstract

Disclosed is a thin film type optical path control device capable of driving an actuator at a larger driving angle and minimizing deterioration of the actuator. The apparatus according to the present invention includes an active matrix having M × N transistors embedded in a matrix form and having a drain formed on one surface thereof, and a support part on one side contacting an upper portion of the active matrix. A membrane including a driving part on the other side having an open portion, ii) a lower electrode formed on the membrane, iii) a strained layer formed on the lower electrode, And an actuator having an upper electrode formed on one side of the strained layer, and a via contact formed from the strained layer to the drain to connect the lower electrode and the drain. Therefore, the device may modify the shape of the membrane to minimize the stress generated between the strained layer, the lower electrode and the membrane, so that the actuator including the strained layer can be driven at a larger driving angle, and the degradation of the actuator can be minimized. have.

Description

Thin Film Type Light Path Regulator

The present invention relates to AMA (Actuated Mirror Arrays), which is a thin film type optical path control device, and more particularly, to a thin film type optical path control device capable of increasing the driving angle of an actuator and minimizing the deterioration of the actuator.

In general, a spatial light modulator, which is an apparatus for projecting optical energy onto a screen, may be variously applied to optical communication, image processing, and information display apparatus. Such devices are classified into a direct view type image display device and a projection type image display device according to a method of projecting a light beam incident from a light source onto a screen. CRT (Cathode Ray Tube) etc. are a direct view type image display apparatus, and a liquid crystal display (LCD), a Deformable Mirror Device (DMD), AMA, etc. are a projection type image display apparatus.

The CRT apparatus has a high image quality but has a disadvantage in that the screen is not large in size. In other words, as the size of the screen increases, the weight and volume of the device increase, thereby increasing the manufacturing cost. Therefore, a liquid crystal display (LCD) that has a simple optical structure and can be formed thin and has a light weight has been developed. However, the liquid crystal display device has a problem that the efficiency is lowered to have a light efficiency of 1 to 2% due to the polarization of the light beam, the response speed of the liquid crystal material therein is slow, and the device tends to overheat. Accordingly, devices such as DMD or AMA have been developed to solve the above problems. Currently, AMA can achieve 10% or more light efficiency, while DMD devices have about 5% light efficiency. In addition, the AMA is not only affected by the polarity of the incident luminous flux but also does not affect the polarity of the luminous flux.

The AMA is a device that can adjust the luminous flux so that each mirror installed therein reflects the light incident from the light source at a predetermined angle, and the reflected light passes through a slit to form an image on the screen. Therefore, the structure and operation principle thereof are simple, and high light efficiency can be obtained compared to a liquid crystal display device or a DMD. In addition, the contrast is improved to obtain a brighter and clearer image. The mirrors embedded in the AMA are arranged corresponding to the slits, and the mirrors are inclined by the generated electric field. Therefore, the luminous flux incident from the light source is adjusted at a predetermined angle to form an image on the screen. In general, each of the actuators formed inside the AMA causes deformation depending on the electric field generated by the applied electrical image signal and the bias voltage. When the actuator causes deformation, each of the mirrors mounted on top of the actuator is inclined. Accordingly, the inclined mirrors can reflect light incident from the light source at a predetermined angle. Piezoelectric ceramics such as PZT (Pb (Zr, Ti) O ₃ ), or PLZT ((Pb, La) (Zr, Ti) O ₃ ) are used as a constituent material of the actuator for driving the respective mirrors. In addition, electrodistorted ceramics such as PMN (Pb (Mg, Nb) O ₃ ) can be used as a constituent material of the actuator.

AMA, which is an optical path control device, is classified into a bulk type and a thin film type. The bulk optical path control device is disclosed in US Pat. No. 5,085,497 to Gregory Um et al. The bulk optical path control device cuts a thin layer of multilayer ceramic and mounts a ceramic wafer having a metal electrode formed therein in an active matrix in which a transistor is built, and then processes it by sawing. This is done by installing a mirror on it. However, the bulk optical path control device requires very high precision in design and manufacturing, and has a problem in that the response speed of the deformable part is slow.

Therefore, a thin film type optical path control apparatus that can be manufactured using a semiconductor manufacturing process has been developed. The thin film type optical path control device is disclosed in Korean Patent Application No. 96-25323 (name of the invention: thin film type optical path control device having a large driving angle), which the applicant has filed a patent with the Korean Patent Office on June 28, 1996.

FIG. 1 shows a plan view of the thin film type optical path adjusting device described in the above prior application, and FIG. 2 shows a cross-sectional view taken along the line AA ′ of the device shown in FIG. 1.

As shown in FIGS. 1 and 2, the thin film type optical path adjusting device includes an active matrix 1 having a drain 2 formed on one surface thereof and an actuator 3 formed on the active matrix 1. Include.

The active matrix 1 having the drain 2 formed thereon includes a protective layer 5 formed on the active matrix 1 and an etch stop layer 7 formed on the protective layer 5. Include.

The actuator 3 includes a membrane 9 formed on the etch stop layer 7, a lower electrode 11 formed on the membrane 9, and a deformation part 13 formed on the lower electrode 11. ), An upper electrode 15 formed on the deformable portion 13, a mirror 17 formed on the upper electrode 15, and a lower electrode 11 and a membrane from an upper portion of the deformed portion 13. (9), a via contact 19 formed vertically through the etch stop layer 7 and the protective layer 5 to the drain 2.

As shown in FIG. 1, the actuator 3 including the membrane 9 corresponds to the head of the letter 'A' in which the driving part with the mirror 17 formed thereon is rotated 90 ° clockwise. The support part divided into the shape has a shape corresponding to the leg portion of the letter 'A' rotated 90 ° clockwise. Therefore, the driving part of the membrane 9 is fitted to the supporting parts which are split to both sides of the membrane of the adjacent actuator, and the driving part of the membrane of the adjacent actuators is fitted to the supporting part to which both sides of the membrane 31 are split. In addition, as shown in FIG. 2, the membrane 9 is in contact with an upper portion of the active matrix 1 on which the etch stop layer 7 is formed, and the other side is interposed through an air gap 8. As a result, it is formed to be parallel to the active matrix 1. In addition, the mirror 17 has the shape of a flat plate having a 'U' shaped groove in the center thereof, the 'U' shaped groove of the mirror 17 is in contact with the upper electrode 15 and both sides are the It is formed to be horizontal to the upper electrode 37.

Hereinafter, a manufacturing process of the thin film type optical path control device will be described with reference to the drawings. 3A to 3C are manufacturing process diagrams of the apparatus shown in FIG. 2.

Referring to FIG. 3A, a protective layer 5 is stacked on top of an active matrix 1 in which M × N (M, N is an integer) MOS transistors are built therein and a drain 2 is formed on one surface thereof. The protective layer 5 is formed of Phospho-Silicate Glass (PSG) to have a thickness of about 1.0 to 2.0 µm using a chemical vapor deposition (CVD) method. The protective layer 5 protects the active matrix 1 in which the transistor is embedded from a subsequent process.

Subsequently, an etch stop layer 7 is laminated on the passivation layer 5. The etch stop layer 7 is formed to have a thickness of about 1000 to 2000 kPa using a low pressure chemical vapor deposition (LPCVD) method. The etch stop layer 7 prevents the protective layer 5 and the active matrix 1 from being etched during the subsequent etching process.

The sacrificial layer 8 is stacked on top of the etch stop layer 7. The sacrificial layer 8 has a thickness of about 1.0 to about 2.0 μm using phosphorous silicate glass (PSG) having a high phosphorus (P) concentration by using an atmospheric pressure chemical vapor deposition (APCVD) method. To form. At this time, since the flatness of the surface of the sacrificial layer 8 covering the surface of the active matrix 1 on which the etch stop layer 7 is formed is very poor, the surface is planarized by a chemical mechanical polishing (CMP) method. A portion of the sacrificial layer 8 in which the drain 2 is formed is etched to expose a portion of the etch stop layer 7. The sacrificial layer 8 is later removed and an air gap 9 is formed at the position of the sacrificial layer 8.

Referring to FIG. 3B, the membrane 9 is stacked on the exposed etch stop layer 7 and on the sacrificial layer 8. The membrane 9 is formed to have a thickness of about 0.1 to 1.0 탆 using low pressure chemical vapor deposition (LPCVD). Subsequently, a lower electrode 11 is stacked on the membrane 9 using platinum (Pt) or platinum-tantalum (Pt-Ta). The lower electrode 11 is formed to have a thickness of about 500 to 2000 micrometers by using a sputtering method.

Deformation portions 13 are stacked on the lower electrode 11. The deformable portion 13 is formed of a piezoelectric ceramic such as PZT or PLZT, or an electrostrictive ceramic such as PMN to have a thickness of about 0.01 to 1.0 탆 using the Sol-Gel method. In addition, the deformable portion 13 may be formed using a chemical vapor deposition (CVD) method. The upper electrode 15 is stacked on the deformation part 13. The upper electrode 15 is formed of aluminum (Al), platinum, or the like so as to have a thickness of about 500 to 2000 mW using a sputtering method. Subsequently, the upper electrode 15, the deformable part 13, the lower electrode 11, and the membrane 9 are sequentially etched and patterned in a pixel shape.

Referring to FIG. 3C, a via contact 19 is formed by sequentially etching the deformable portion 13, the lower electrode 11, the membrane 9, the etch stop layer 7, and the protective layer 5. do. The via contact 19 forms tungsten (W), titanium, or the like vertically from the top of the deformable portion 13 to the drain 2 using a lift-off method. Therefore, the via contact 19 electrically connects the drain 2 and the lower electrode 11. Subsequently, a mirror 17 is formed on the upper electrode 15. The mirror 17 is formed using conventional photolithography methods and sputtering methods. The mirror 17 is formed to have a thickness of about 500 to 1000 mm by using silver (Ag) or aluminum. The sacrificial layer 8 is etched using hydrogen fluoride (HF) vapor, and then washed and dried to complete the AMA device.

In the above-described thin film type optical path adjusting device, the image signal generated from the MOS transistor (not shown) embedded in the active matrix 1 is transferred to the lower electrode 11 through the drain 2 and the via contact 19. Is applied. At the same time, a bias voltage is applied to the upper electrode 15. Therefore, an electric field is generated between the upper electrode 15 and the lower electrode 11. By this electric field, the deformation | transformation part 13 shrinks in a vertical direction. Therefore, the actuator 3 including the deformation part 13 is bent in the direction opposite to the direction in which the membrane 9 is formed. Since the mirror 17 reflecting the light beam incident from the light source is formed on the actuator 3, the mirror 3 is inclined at a predetermined angle as the actuator 3 is bent. The light beam incident from the light source is reflected by the mirror 17 at a predetermined angle to form an image on the screen through the slit. At this time, as the length of the actuator 3 becomes longer, the driving angle of the driving portion of the actuator 3 becomes larger. Therefore, as shown in FIG. 1, the thin film type optical path adjusting device can determine the maximum length of the actuator 3 as follows.

Referring to FIG. 1, the horizontal and vertical lengths of the pixels are each l, the minimum line width of the actuator 3 is b, the spacing between adjacent actuators is t, and the actuator 3 is at an inclination angle of θ with respect to the horizontal plane. When the maximum length of the actuator (3) is L,

And

Becomes

When sin θ is canceled in the above two equations, the maximum length L of the actuator 3 is determined by the following equation.

Therefore, the thin film type optical path adjusting device causes the actuator 3 to be bent with the maximum length so that the mirror 17 formed on the upper part of the actuator 3 is inclined with the maximum angle.

However, in the thin film type optical path adjusting device described in the above prior application, when the deformable portion, the lower electrode and the membrane are adhered in turn, and the deformable portion causes the deformation, the lower electrode and the membrane are deformed together so that the lower electrode and the membrane between There is a problem that the stress is generated so that the deformation portion does not cause deformation with a sufficient angle. In addition, as the deformation of the deformable portion is repeated according to the electric field generated between the upper electrode and the lower electrode, the lower electrode is shorted due to the stress generated between the deformed portion, the lower electrode, and the lower electrode and the membrane, thereby causing malfunction of the device. And, there was a disadvantage that the deterioration of the actuator including them is accelerated.

Accordingly, an object of the present invention is to have a membrane having a shape capable of minimizing the stress generated, the actuator can be driven with a larger driving angle, the deterioration of the actuator can be minimized, and the malfunction of the device can be prevented The present invention provides a thin film type optical path control device.

1 is a plan view of a thin film-type optical path control device previously applied by the present applicant.

FIG. 2 is a cross-sectional view taken along line A′A ′ of the apparatus shown in FIG. 1.

3A to 3C are manufacturing process diagrams of the apparatus shown in FIG.

4 is a plan view of a thin film type optical path control device according to a first embodiment of the present invention.

FIG. 5 is a cross-sectional view taken along line B′B ′ of the apparatus shown in FIG. 4.

6 is a perspective view of the membrane of the apparatus shown in FIG. 5.

7A to 7C are manufacturing process diagrams of the apparatus shown in FIG.

8 is a cross-sectional view of a thin film type optical path control apparatus according to a second embodiment of the present invention.

FIG. 9 is a perspective view of the membrane of the apparatus shown in FIG. 8. FIG.

10A to 10C are manufacturing process diagrams of the apparatus shown in FIG. 8.

<Explanation of symbols for main parts of drawing>

31: Active matrix 32: Drain

33: protective layer 35: etching prevention layer

37, 37a: Membrane 38: Air gap

39: lower electrode 41: strained layer

43: upper electrode 45: mirror

52: Beer hall 53: Beer contact

57: Actuator

The present invention to achieve the above object,

An active matrix having M × N (M, N is an integer) transistors embedded in a matrix and having a drain formed on one surface thereof; And

A membrane having a support part on one side of the active matrix contacting the upper part of the active matrix and a driving part on the other side formed to be parallel to the active matrix via an air gap and having an open part; Ii) a lower electrode formed on the membrane; A strained layer formed on the lower electrode; An upper electrode formed on one side of the strained layer; And an actuator including a via contact formed from the strained layer to the drain to connect the lower electrode and the drain.

In the above-described thin film type optical path control device according to the present invention, the image signal generated from the MOS transistor embedded in the active matrix is applied to the lower electrode which is the signal electrode through the drain and via contact. In addition, a bias voltage is applied to the upper electrode, which is a common electrode, to generate an electric field between the upper electrode and the lower electrode. By this electric field, the strained layer laminated between the upper electrode and the lower electrode causes deformation. The strained layer contracts in a direction perpendicular to the electric field, so that the actuator including the strained layer is bent in a direction opposite to the direction in which the membrane is formed. Therefore, the mirror on the top of the actuator is also inclined in the same direction. The light beam incident from the light source is reflected by a mirror formed on the upper electrode, and is then projected onto a screen to form an image.

When the strained layer causes the strain, the lower electrode under the strained layer and the membrane under the lower electrode also cause strain in the same direction as the strained layer. In this case, stress is generated on the contact surface of the strained layer and the lower electrode and the contact surface of the lower electrode and the membrane. In the conventional thin film type optical path control device, it is difficult to drive the deformation layer with a large driving angle due to such stress, and the deterioration of the actuator is likely to be accelerated. However, in this embodiment, the driving portion of the membrane has a shape in which a plurality of contact portions and opening portions are repeated on both sides of the center portion to minimize the stress generated when the strain layer causes deformation. That is, when the lower electrode is deformed according to the deformation of the strained layer, an opening is formed in the membrane below the lower electrode so that the lower electrode is not in contact with the lower electrode. Stress is minimized. Therefore, the strained layer can be driven at a larger driving angle, and the deterioration of actuators including them can be minimized.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

Example 1

4 is a plan view showing a thin film type optical path adjusting device according to the present embodiment, FIG. 5 is a cross-sectional view taken along line BB ′ of the device shown in FIG. 4, and FIG. 6 is a view of the device shown in FIG. 5. A perspective view of the membrane is shown.

4 and 5, the thin film type optical path adjusting apparatus according to the present embodiment includes an active matrix 31 and an actuator 57 formed on the active matrix 31.

M x N (M, N is an integer) MOS transistors (not shown) are built therein, and the active matrix 31 having a drain 32 formed on one surface thereof has a protective layer formed thereon. 33) and the etch stop layer 35 formed on the protective layer 33.

One side of the actuator 57 is in contact with the upper portion of the etch stop layer 35, and the other side of the membrane 37, the membrane 37 formed to be parallel to the etch stop layer 35 through the air gap 38. A lower electrode 39 formed on the upper portion, a strained layer 41 formed on the lower electrode 39, an upper electrode 43 formed on one side of the strained layer 41, and a mirror formed on the upper electrode 43. 45, vertically from the top of the other side of the strained layer 41 to the drain 32 through the strained layer 41, the lower electrode 39, the membrane 37, the etch stop layer 35, and the protective layer 33. A via hole 52 is formed, and a via contact 53 is formed to connect the lower electrode 39 and the drain 32 in the via hole 52.

Referring to FIG. 6, the membrane 37 may contact the upper portion of the drain 32 of the active matrix 31 and the active matrix 31 through the air gap 38. It includes a driving unit 110 formed integrally with the support 100 to be parallel. The driving unit 110 has a shape of a rib in which a plurality of contact parts 117 and a plurality of opening parts 115 are alternately formed at both sides of the center part 113 in contact with the lower electrode 39. Has

Hereinafter, a method of manufacturing a thin film type optical path adjusting device according to the present embodiment will be described with reference to the drawings.

7A to 7C are manufacturing process diagrams of the thin film type optical path control device according to the present embodiment. In Figs. 7A to 7C, the same reference numerals are used for the same members as Figs. 5 and 6.

Referring to FIG. 7A, a drain 32 is formed by stacking a metal such as tungsten or titanium on one surface of an active matrix 31 having M × N transistors. Subsequently, a protective layer 33 having a thickness of about 1.0 to 2.0 µm is laminated on the active matrix 31. The protective layer 33 is formed of a silicate glass (PSG) using a chemical vapor deposition (CVD) method. The protective layer 33 prevents damage to the active matrix 31 in which the transistor is embedded during the subsequent process.

An etch stop layer 35 is stacked on the passivation layer 33. The etch stop layer 35 is formed to have a thickness of about 1000 to 2000 GPa using a low pressure chemical vapor deposition (LPCVD) method. The etch stop layer 35 prevents the protective layer 33 and the active matrix 31 from being etched during the subsequent etching process.

The sacrificial layer 36 is stacked on the etch stop layer 35. The sacrificial layer 36 is formed of a phosphorus silicate glass (PSG) having a high phosphorus (P) concentration to have a thickness of about 1.0 to about 2.0 μm using an atmospheric pressure chemical vapor deposition (APCVD) method. In this case, since the flatness of the surface of the sacrificial layer 36 covering the surface of the active matrix 31 on which the etch stop layer 35 is formed is very poor, the surface of the sacrificial layer 36 by the chemical mechanical polishing (CMP) method. Planarize. A portion of the sacrificial layer 36 in which the drain 32 is formed is etched to expose a portion of the etch stop layer 35.

Referring to FIG. 7B, a membrane 37 is deposited on the exposed etch stop layer 35 and on the sacrificial layer 36. The membrane 37 is formed to have a thickness of about 0.1 to 1.0 탆 using a low pressure chemical vapor deposition (LPCVD) method. Subsequently, the membrane 37 is patterned using a conventional photolithography method, and a plurality of contacts 117 and openings 115 are formed on both sides of the central portion 113 as shown in FIG. 6. Have a rib shape that repeats alternately. Subsequently, the opening 115 of the membrane 37 is filled with a polyimide polymer using a spin coating method so that the membrane 37 has a flat surface.

The lower electrode 39 is stacked on the membrane 37 by using platinum or platinum-tantalum (Pt-Ta). The lower electrode 39 is formed to have a thickness of about 500 to 2000 microns using a sputtering method. The strained layer 41 is stacked on the lower electrode 39. The strained layer 41 is formed such that piezoelectric ceramics such as PZT or PLZT, or electrodistorted ceramics such as PMN have a thickness of about 0.1 to 1.0 탆, preferably about 0.4 탆 using a sol-gel method. do. In addition, the strained layer 41 may be formed using a chemical vapor deposition (CVD) method. In addition, an upper electrode 43 is stacked on one side of the strained layer 41. The upper electrode 43 is formed to have a thickness of about 500 to 2000 micrometers by using a sputtering method of aluminum or platinum. Subsequently, the upper electrode 43, the deformable portion 41, the lower electrode 39, and the membrane 37 are sequentially etched and patterned in a pixel shape.

Referring to FIG. 7C, a mirror 45 having a shape of a flat plate having a 'U'-shaped groove is formed in a central portion of the upper electrode 43. The mirror 45 is formed using a photolithography method and a sputtering method. The mirror 45 is formed to have a thickness of about 500 to 1000 mm using a metal having excellent reflection characteristics such as silver or aluminum. Subsequently, the strained layer 41, the lower electrode 39, the membrane 37, the etch stop layer 35, and the protective layer 33 are sequentially etched from the upper side of the other strained layer 41 to form the strained layer 41. The via hole 52 is formed vertically from the top to the drain 32. The via contact 53 is continuously formed in the via hole 52 from the lower electrode 39 to the drain 32 by sputtering a metal having excellent electrical conductivity such as tungsten or titanium. Therefore, the via contact 53 electrically connects the drain 32 and the lower electrode 39. Then, the polyimide-based polymer filling the sacrificial layer 36 and the opening 115 of the membrane 37 using hydrogen fluoride (HF) is etched, and then washed and dried to control the thin film type optical path control device. Complete the device.

In the above-described thin film type optical path adjusting device, the image signal generated from the MOS transistor embedded in the active matrix 31 is transferred to the lower electrode 39 which is a signal electrode through the drain 32 and the via contact 53. Is approved. In addition, a bias voltage is applied to the upper electrode 43, which is a common electrode, to generate an electric field between the upper electrode 43 and the lower electrode 39. The strained layer 41 stacked between the upper electrode 43 and the lower electrode 39 causes deformation by this electric field. The strained layer 41 contracts in a direction perpendicular to the electric field, so that the actuator 57 including the strained layer 41 is bent in a direction opposite to the direction in which the membrane 37 is formed. Therefore, the mirror 45 on the actuator 57 also inclines in the same direction. The light beam incident from the light source is reflected by the mirror 45 formed on the upper electrode 43, and then is projected onto the screen to form an image.

When the strained layer 41 causes deformation, the lower electrode 39 under the strained layer 41 and the membrane 37 under the lower electrode 39 also cause strain in the same direction as the strained layer 41. . In this case, stress is generated at the contact surface of the strained layer 41 and the lower electrode 39 and at the contact surface of the lower electrode 39 and the membrane 37. In the conventional thin film type optical path control device, it is difficult to drive the deformation layer with a large driving angle due to such stress, and the deterioration of the actuator is likely to be accelerated. However, in this embodiment, the drive layer 110 of the membrane 37 has a shape in which a plurality of contact portions 117 and an opening portion 115 are repeated on both sides of the center portion 113 so as to have a deformation layer 41. ) Can minimize the stress that occurs when deformation occurs. That is, when the lower electrode 39 deforms due to the deformation of the strained layer 41, the opening 115 is not formed in the membrane 37 under the contact with the lower electrode 39. Since the stress is not generated in the portion 115, the stress generated between the membrane 37 and the lower electrode 39 is minimized. Therefore, the strained layer 41 can be driven at a larger driving angle, and the deterioration of the actuator 57 including them can be minimized.

Example 2

FIG. 8 is a sectional view of a thin film type optical path adjusting device according to the present embodiment, and FIG. 9 is a perspective view of a membrane of the device shown in FIG. 8.

Top and cross-sectional views of the thin film type optical path control apparatus according to the present embodiment are the same as those of FIGS. 4 and 5 of the first embodiment except for the membrane. In FIG. 8, the same reference numerals are used for the same members as in FIG. 5 except for the membrane. Therefore, the configuration of the thin film type optical path control device according to the present embodiment is the same as that of the first embodiment except for the membrane.

8 and 9, the membrane 37a of the thin film type optical path adjusting device according to the present embodiment includes a support part 200 contacting a portion of the etch stop layer 35 in which a drain 32 is formed below. The driving unit 210 is integrally formed with the support part 200 to be parallel to the active matrix 31 via the air gap 38. The driving unit 210 has a shape of a flat plate in which a plurality of rectangular openings 220 are sequentially formed.

Hereinafter, a method of manufacturing a thin film type optical path adjusting device according to the present embodiment will be described with reference to the drawings.

10A to 10C are manufacturing process diagrams of the thin film type optical path adjusting device according to the present embodiment. In Figs. 10A to 10C, the same reference numerals are used for the same members as Figs. 8 and 9.

Referring to FIG. 10A, in the present embodiment, the process of etching the portion of the sacrificial layer 36 in which the drain 32 is formed at the lower portion to expose a portion of the etch stop layer 35 is the same as that of the first embodiment. same.

Referring to FIG. 10B, a membrane 37a is stacked on the exposed etch stop layer 35 and on the sacrificial layer 36. The membrane 37a is formed to have a thickness of about 0.1 to 1.0 탆 using low pressure chemical vapor deposition (LPCVD). Subsequently, the membrane 37a is patterned using a photolithography method, and as shown in FIG. 9, the driving unit 210 of the membrane 37a is formed of a flat plate having a plurality of rectangular openings 220 arranged in a row. Have a shape. Subsequently, the opening 220 of the membrane 37a is filled with a polyimide-based polymer using a spin coating method so that the driving unit 210 of the membrane 37a has a flat surface. In addition, the constituent materials and forming methods of the lower electrode 39, the strained layer 41, and the upper electrode 43 are the same as those of the first embodiment.

Referring to FIG. 10C, after the mirror 45, the via hole 52, and the via contact 53 are formed except the membrane 37a, the sacrificial layer 36 and the holes 220 of the membrane 37a may be formed. ), A method of etching a polyimide-based polymer filled with a) and cleaning and drying to complete a thin film type optical path control device element is the same as in Example 1.

In addition, in the thin film type optical path control apparatus according to the present embodiment, a process in which the mirror 45 is inclined by the deformation of the deformation layer 41 to reflect the light beam incident from the light source to be projected onto the screen to form an image. Same as the case of 1.

When the strained layer 41 causes strain, the lower electrode 39 under the strained layer 41 and the membrane 37a under the lower electrode 39 also cause strain in the same direction as the strained layer 41. . In this case, stress is generated on the surface where the strained layer 41 and the lower electrode 39 contact and the surface where the lower electrode 39 and the membrane 37a contact. In the conventional thin film type optical path control device, it is difficult to drive the deformation layer with a large driving angle due to such stress, and the deterioration of the actuator is likely to be accelerated. However, in the present embodiment, the stress generated when the strained layer 41 deforms by causing the drive portion 210 of the membrane 37a to have the shape of a flat plate having a plurality of rectangular openings 220 formed in a row. Can be minimized. That is, when the lower electrode 39 deforms due to the deformation of the strained layer 41, a plurality of openings 220 which are not in contact with the lower electrode 39 are formed in the membrane 37a thereunder. Since the stress does not occur in the opening 220, the stress generated between the membrane 37a and the lower electrode 39 is minimized. Therefore, the strained layer 41 can be driven at a larger driving angle, and the deterioration of the actuator 57 including them can be minimized.

Therefore, in the above-described thin film type optical path control apparatus according to the present invention, the actuator including the strained layer can be driven at a larger driving angle by minimizing the stress generated between the strained layer, the lower electrode, and the membrane by modifying the shape of the membrane. In addition, the deterioration of the actuator can be minimized.

In preferred embodiments of the present invention, the driving portion of the membrane has a rib shape in which a plurality of contact portions and a plurality of opening portions in which both sides are in contact with the lower electrode with respect to the center portion are alternately formed, or a plurality of rectangular shapes The opening has a shape of a flat plate formed in a row, but from this there is a membrane having a drive section formed with a plurality of circular openings in a row, or a driving section in which M × N (M, N is an integer) square shaped openings are formed. It will be appreciated that various membranes may be formed in which contact portions in contact with a lower electrode such as a membrane having an open portion and open portions not in contact with the lower electrode are formed together.

As mentioned above, although this invention was demonstrated and demonstrated in detail by the preferred embodiment, this invention is not limited by this, A person of ordinary skill in the art can modify and improve it within a normal range.

Claims (7)

An active matrix 31 having M × N (M, N is an integer) transistors embedded in a matrix and having a drain 32 formed on one surface thereof; And It is formed and opened in parallel with the active matrix 31 via the support part 100 of one side in contact with the upper portion of the active matrix 31 and the air gap 38 on the top of the active matrix 31. A membrane 37 having an additional drive part 110 formed thereon; Ii) a lower electrode 39 formed on the membrane 37; A strained layer 41 formed on the lower electrode 39; An upper electrode 43 formed on one side of the strained layer 41; And an actuator (57) including a via contact (39) formed from the strained layer (41) to the drain (22) to connect the lower electrode (39) and the drain (22). The method of claim 1, wherein the active matrix 31 is stacked on top of the active matrix 31 to protect the active matrix 31 and the top of the protective layer 33. Thin film type optical path control device, characterized in that further comprising an etch stop layer (35) to prevent the protective layer (33) and the active matrix (31) is etched. The rib membrane of claim 1, wherein the membrane 37 has a plurality of rectangular openings 115 and a plurality of rectangular contact portions 117 alternately formed around the central portion 113. A thin film type optical path control device, characterized in that the flat plate. The apparatus of claim 1, wherein the membrane (37a) is a flat plate having a plurality of rectangular openings (220) formed in a line in the contact portion (230). The apparatus of claim 1, wherein the membrane (37a) is a flat plate having a plurality of circular openings formed in a line in the contact portion (230). The apparatus of claim 1, wherein the membrane (37a) is a flat plate having M × N (M, N is an integer) square openings formed in a matrix form at the contact portion (230). According to claim 1, wherein the actuator 57 further comprises a mirror 45 formed on the upper electrode 43, the mirror 45 is formed of a flat plate having a 'U' shaped groove in the center The thin film type optical path control device having a shape, characterized in that the 'U'-shaped groove is in contact with the upper electrode 43 and both sides are formed to be horizontal to the upper electrode 43.