KR19980046146A - Manufacturing method of thin film type optical path control device which can improve light efficiency - Google Patents

Abstract

Disclosed is a method of manufacturing a thin film type optical path control device capable of improving light efficiency. The method includes providing an active matrix having M × N transistors embedded therein and having a drain formed on one side thereof, forming a sacrificial layer on the active matrix, and forming a first membrane on the sacrificial layer. Polishing the first membrane until the sacrificial layer is exposed, forming a second membrane on top of the exposed sacrificial layer and the first membrane, a bottom on top of the second membrane Forming an electrode, forming a strain layer on the lower electrode, forming an upper electrode on the strain layer, and patterning the upper electrode, the strain layer, the lower electrode, and the membrane Steps. According to the method, it is possible to improve the flatness of the actuator formed in the subsequent process by filling the membrane to compensate for the step of the sacrificial layer formed when the sacrificial layer is patterned to form the support of the actuator. Therefore, the initial tilting of the actuator can be prevented to improve the light efficiency of the light beam incident from the light source, thereby forming an image having higher brightness and higher image quality.

Description

Manufacturing method of thin film type optical path control device which can improve light efficiency

The present invention relates to a method for manufacturing Actuated Mirror Arrays (AMA), which is a thin film type optical path control device, and more particularly, to compensate for a step of a sacrificial layer formed when patterning a sacrificial layer to form a support part of an actuator. The present invention relates to a method of manufacturing a thin film type optical path control device capable of minimizing initial tilting to improve flatness of an actuator and consequently improving light efficiency of a light beam incident from a light source.

In general, an optical path adjusting apparatus or an optical modulator capable of adjusting a light beam incident from a light source may be variously applied to optical communication, image processing, and information display apparatus. In general, such devices are classified into two types according to their optical properties.

One type is a direct view type image display device, such as a CRT (Cathode Ray Tube), and the other type is a projection type image display device, a liquid crystal display (LCD), an AMA, or a deformable mirror device (DMD). ) And the like. Although the CRT device has excellent image quality, there is a problem that the weight and volume of the device increase and the manufacturing cost increases as the screen is enlarged. On the other hand, the liquid crystal display (LCD) has an advantage in that the optical structure is simple to form a thin layer so that the weight of the device can be reduced and the volume can be reduced. However, the liquid crystal display has a disadvantage in that the efficiency is low enough to have a light efficiency of 1 to 2% due to the polarized light, the response speed of the liquid crystal material is slow, and the inside thereof is easily overheated. Therefore, an image display device such as AMA or DMD has been developed to solve the above problem. Currently, AMA has a light efficiency of 10% or more, compared to a DMD device having a light efficiency of about 5%.

The AMA is a device that can adjust the luminous flux so that each of the mirrors installed therein reflects the light incident from the light source at a predetermined angle, and the reflected light passes through a slit and is projected onto the screen to form an image. to be. 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 bright and clear image. The mirrors built into the AMA are inclined by the electric field generated in correspondence with the slits. 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 actuator causes deformation in accordance with the electric field generated by the applied electric 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 materials such as PZT (Pb (Zr, Ti) O ₃ ), or PLZT ((Pb, La) (Zr, Ti) O ₃ ) are used as actuators for driving the respective mirrors. In addition, the actuator can be configured as a warping material such as PMN (Pb (Mg, Nb) O ₃ ).

The optical path control device using AMA is largely classified into a bulk type and a thin film type. The bulk optical path control device is described, for example, in US Pat. Nos. 5,085,497 (issued to Gregory Um, et al.), 5,159,225 (issued to Gregory Um, et al.), 5,175,465 (issued to Gregory Um, et. al.) and the like. The bulk optical path control device cuts a thin layer of multilayer ceramic, mounts a ceramic wafer having a metal electrode therein in an active matrix including a transistor, and then processes it by sawing and mirrors on the top. It is done by installation. However, bulk devices require high precision in design and manufacture because the actuators must be separated by a sawing method, and the response speed of the deformation part is slow. Therefore, a thin film type optical path control apparatus that can be manufactured using a semiconductor manufacturing process has been developed.

Such a thin film type optical path control device is disclosed in Patent Application No. 95-13353 (name of the invention: a method of manufacturing an optical path control device), filed by the applicant on May 26, 1995. 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 Fig. 1 and Fig. 2, the thin film type optical path adjusting device is composed of an active matrix 1 and an actuator 3 provided on the active matrix 1.

The active matrix 1 is made of a semiconductor such as silicon (Si), and includes M x N (M, N is an integer) MOS transistors (not shown). In addition, the active matrix 1 may be formed of an insulating material such as glass and alumina (Al ₂ O ₃ ). The pad 5 is formed on one side of the active matrix 1. The pad 5 is electrically connected to a transistor embedded in the active matrix 1.

The actuator 3 is composed of a membrane 7, a plug 9, a lower electrode 11, a deformable portion 15, and an upper electrode 17.

As shown in FIG. 1, the membrane 7 has a rectangular concave portion formed at one side of a center portion of the actuator 3, and a quadrangular protrusion portion corresponding to the concave portion is formed at the other side thereof. . The protrusion of the membrane of the actuator adjacent to the concave portion of the membrane 7 is fitted, and the protrusion of the membrane 7 is fitted into the concave portion of the adjacent actuator. Also, referring to FIG. 2, a portion of one side of the membrane 7 is in contact with an upper portion of the active matrix 1 in which the pad 5 is formed, and the other side of the membrane 7 is disposed through an air gap 8. It is formed to be parallel to the matrix 1.

The plug 9 is formed perpendicular to the portion of the membrane 7 in which the pad 5 is formed. The plug 9 is electrically connected to the pad 5. The lower electrode 11 is formed on the membrane 7, and the deformable part 15 is formed on the lower electrode 11. The upper electrode 17 is formed on the deformation part 15. The upper electrode 17 performs not only a function of an electrode but also a mirror reflecting an incident light beam.

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

3A to 3E show a manufacturing process diagram of the apparatus shown in FIG. Referring to FIG. 3A, a sacrificial layer 2 made of Phospho-Silicate Glass (PSG) is stacked on an active matrix 1 having a pad 5 formed on one side thereof. The sacrificial layer 2 is formed to have a thickness of about 1.0 to 2.0 µm using the CVD method. Subsequently, after the photoresist layer (not shown) is applied on the sacrificial layer 2, a part of the sacrificial layer 2 is etched to form a pad 5 on the top of the active matrix 1. Expose the part.

Referring to FIG. 3B, a membrane 7 having a thickness of about 0.1 to 1.0 μm is stacked on the exposed portion of the active matrix 1 and the sacrificial layer 2. The membrane 7 is formed using sputtering or chemical vapor deposition (CVD) of silicon nitride (Si ₃ N ₄ ). Subsequently, a portion of the membrane 7 formed on the exposed portion of the active matrix 1 is etched by the conventional photolithography method to form the opening 6.

Through the opening 6, a plug 9 made of a metal having good electrical conductivity such as tungsten (W) or titanium (Ti) is formed. The plug 9 is formed using a lift-off method to be electrically connected to the pad 5.

The lower electrode 11 is stacked on the membrane 7 in which the opening 6 is formed. The lower electrode 11 is formed to have a thickness of about 500 to 2000 micrometers of platinum (Pt) or platinum-titanium (Pt-Ti) by using vacuum deposition or sputtering. The lower electrode 11 is electrically connected to the plug 9, and thus the pad 5, the plug 9 and the lower electrode 11 are electrically connected to each other.

Referring to FIG. 3C, the deformation part 15 is stacked on the lower electrode 11. The deformable portion 15 is formed to have a thickness of about 0.01 to 1.0 탆 using piezoelectric materials such as PZT or PLZT, or electrostrictive materials such as PMN. The deformable part 15 is formed by using a sol-gel method or a chemical vapor deposition method (CVD).

The upper electrode 17 is stacked on the deformable portion 15. The upper electrode 17 is formed to have a thickness of about 500 to 1000 Å by sputtering or vacuum deposition. Subsequently, the upper electrode 17, the deformable portion 15, the lower electrode 11, and the membrane 7 are sequentially etched from the top by using a photolithography method to pattern the pattern. In this case, the upper electrode 17, the deformable part 15, and the lower electrode 11 are etched to be separated from the upper electrode, the deformable part, and the lower electrode of an adjacent actuator. At the same time, the membrane 7 is etched to be connected with the membrane of the adjacent actuator. The protective layer 18 is formed by coating a photoresist on a side surface generated when the upper electrode 17 and the actuators are separated from each other.

Referring to FIG. 3D, the sacrificial layer 2 is etched using an oxide buffered etchant (BOE) in which ammonium fluoride (NH ₄ F) and hydrogen fluoride (HF) are mixed to form an air gap. gap) 8 is formed. In addition, the protective layer 18 is removed by a wet etching method, and the remaining etching solution is washed with deionized water. Subsequently, a photoresist is coated on the upper electrode 17 to form a mask 19.

Referring to FIG. 3E, the portion of the membrane 7 connected to the membrane of the adjacent actuator is etched using the reactive ion etching (RIE) method using the mask 19 as an etching mask. Then, the mask 19 is removed by an oxygen plasma method to complete the AMA 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 1 is applied to the lower electrode 11 through the pad 5 and the plug 9. At the same time, a bias voltage is applied to the upper electrode 17 to generate an electric field between the upper electrode 17 and the lower electrode 11. By this electric field, the deformation | transformation part 15 shrinks in the direction perpendicular | vertical to an electric field. Accordingly, the actuator 3 is bent in the opposite direction to the direction in which the membrane 7 is formed, and the upper electrode 17 on the actuator 3 reflects the light beam incident from the light source. The light beam reflected by the upper electrode 17 is projected onto the screen through the slit to form an image.

However, in the thin film type optical path adjusting apparatus described in the above-mentioned prior application, after laminating a portion of the sacrificial layer to form a support part of the actuator after laminating the sacrificial layer, and depositing a thin film of a subsequent process on the sacrificial layer, Unevenness in the shape (particularly flatness) of the thin film is caused by the step of the sacrificial layer. That is, since the thin films deposited later are excessively deposited on the exposed portion of the sacrificial layer than other portions, the actuator is not formed in a horizontal state accurately and the actuator causing deformation according to the electric field is initially bent in the state without applying an electric field. There was a problem of having. In addition, due to the initial tilt of the actuator, there is a problem that the stress between the thin films stacked in a subsequent process is not uniform, thereby accelerating deterioration of the entire actuator.

Accordingly, an object of the present invention is subsequently formed by etching and patterning a portion of the sacrificial layer to form a support of the actuator, and then filling the portion where the support of the actuator is to be formed with a membrane to compensate for the step of the sacrificial layer. The present invention provides a method of manufacturing a thin film type optical path control apparatus that can improve flatness of an actuator and prevent initial bending of the actuator.

1 is a plan view of a thin film type optical path adjusting device described in the applicant's prior application.

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

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

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

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

6A to 6E are manufacturing process diagrams of the apparatus shown in FIG.

* Description of the symbols for the main parts of the drawings *

31: active matrix 32: actuator

33: drain 35: protective layer

37: anti-etching layer 39: sacrificial layer

45a: first membrane 45b: second membrane

47: lower electrode 49: strained layer

51: upper electrode 53: air gap

55: Beer Hall 57: Beer Contact

The present invention to achieve the above object,

Providing an active matrix having M × N transistors embedded therein and having a drain formed on one side thereof;

Forming a sacrificial layer on top of the active matrix;

Forming a first membrane on top of the sacrificial layer;

Polishing the first membrane until the sacrificial layer is exposed;

Forming a second membrane on top of the exposed sacrificial layer and first membrane;

Forming a lower electrode on the second membrane;

Forming a strained layer on the lower electrode;

Forming an upper electrode on the strain layer; And

It provides a method of manufacturing a thin film type optical path control device comprising the step of patterning the upper electrode, the strain layer, the lower electrode and the membrane.

In the thin film type optical path adjusting device according to the present invention, an image signal generated from a transistor embedded in an active matrix is applied to a lower electrode which is a signal electrode through a 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, and the actuator including the strained layer and the membrane is bent in a direction opposite to the direction in which the membrane is formed. Therefore, the upper electrode on the actuator is also inclined in the same direction. Since the upper electrode also functions as a mirror that reflects the luminous flux, the luminous flux incident from the light source is reflected by the inclined upper electrode at a predetermined angle, and is then projected onto a screen to form an image.

Therefore, in the manufacturing method of the thin film type optical path control apparatus according to the present invention, by filling the membrane to compensate for the step of the sacrificial layer for forming the support of the actuator, the subsequent actuator can be formed flat to prevent the initial bending of the actuator. Can be.

Hereinafter, a method of manufacturing a thin film type optical path control apparatus according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

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

4 and 5, the thin film type optical path adjusting apparatus according to the present invention includes an active matrix 31 and an actuator 32 formed on the active matrix 31. The active matrix 31 may include a drain 33 formed on one surface of the active matrix 31, a passivation layer 35 stacked on the active matrix 31 and the drain 33. And an etch stop layer 37 stacked on the protective layer 35.

The actuator 32 is a membrane (membrane) laminated so that one side is in contact with the portion of the anti-etching layer 37 in which the drain 33 is formed at the lower side and the other side is parallel to the etching preventing layer 37 through the air gap 53. 45, the bottom electrode 47 stacked on the membrane 45, the active layer 49 and the deformation layer 49 stacked on the lower electrode 47. The top electrode 51 stacked on one side and the strained layer 49, the lower electrode 47, the membrane 45, the etch stop layer 37, and the protective layer 35 from the other side of the strained layer 49. The via hole 55 includes a via hole 55 formed vertically through the drain 33, and a via contact 57 formed in the via hole 55.

In addition, referring to FIG. 4, one side of the membrane 45 has a concave portion having a rectangular shape at the center thereof, and the concave portion is formed in a stepped shape toward both edges. The other side of the membrane 45 has a quadrangular protrusion that narrows stepwise toward the central portion corresponding to the concave portion. Therefore, the concave portion of the membrane of the actuator adjacent to the concave portion of the membrane 45 is fitted, and the rectangular projection is fitted to the concave portion of the adjacent membrane.

Hereinafter, a method of manufacturing a thin film type optical path control device according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

6A to 6E are manufacturing process diagrams of the apparatus shown in FIG. 6A to 6E, the same reference numerals are used for the same members as in FIG.

Referring to FIG. 6A, a protective layer 35 is disposed on an active matrix 31 having M × N metal oxide semiconductor (MOS) transistors (not shown) and a drain 33 formed on one side thereof. )). The active matrix 31 is made of a semiconductor such as silicon (Si) or an insulating material such as glass or alumina (Al ₂ O ₃ ). The protective layer 35 is formed to have a thickness of about 0.01 to 1.0 μm using phosphorus silicate glass (PSG) using a chemical vapor deposition (CVD) method. The protective layer 35 prevents the transistor embedded in the active matrix 31 from being damaged during subsequent processing.

An etch stop layer 37 is stacked on the passivation layer 35. The etch stop layer 37 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 37 prevents the active matrix 31 and the protective layer 35 from being etched due to the subsequent etching process.

The sacrificial layer 39 is stacked on the etch stop layer 37. The sacrificial layer 39 is formed of phosphorus silicate glass (PSG) to have a thickness of about 0.5 to 4.0 μm by an atmospheric pressure chemical vapor deposition (APCVD) method. In this case, since the sacrificial layer 39 covers the upper portion of the active matrix 31 in which the transistor is embedded, the flatness of the surface thereof is very poor. Accordingly, the surface of the sacrificial layer 39 is planarized by using a spin on galss (SOG) method or a chemical mechanical polishing (CMP) method. Subsequently, a part of the sacrificial layer 39 is etched to expose a portion of the etch stop layer 37 in which the drain 33 is formed below.

Referring to FIG. 6B, a first membrane 45a having a thickness of about 2.0 μm is stacked on the exposed etch stop layer 37 and on the sacrificial layer 39. The first membrane 45a is formed by sputtering or chemical vapor deposition (CVD). When the first membrane 45a is stacked as described above, the first membrane 45a is formed on the sacrificial layer 39 while filling the exposed portion of the etch stop layer 37. Subsequently, the first membrane 45a is polished using a CMP method to expose the sacrificial layer 39. As a result, the step of the sacrificial layer 39 may be compensated by the first membrane 45a filling the exposed portion of the sacrificial layer 39. Therefore, since the sacrificial layer 39 and the first membrane 45a are formed flat, the thin films constituting the actuator to be deposited later may also be stacked in a flat manner, thereby preventing initial bending of the actuator. The first membrane 45a becomes a support of the second membrane 45b formed later.

Referring to FIG. 6C, a second membrane 45b is stacked on the exposed sacrificial layer 39 and the first membrane 45a. The second membrane 45b is formed by sputtering or chemical vapor deposition (CVD) the same nitride as the first membrane 45a filling the stepped portion of the sacrificial layer 39 to form the support of the actuator. It is formed to have a thickness of about 0.01 to 1.0㎛.

Subsequently, a lower electrode 47 made of platinum (Pt), platinum-tantalum (Pt-Ta), or the like is stacked on the second membrane 45b. The lower electrode 47 is 0.1-1. 1 using a sputtering method. It is formed to have a thickness of about 0㎛. An image signal is applied to the lower electrode 47, which is a signal electrode, from the transistor built in the active matrix 31 through the drain 33.

The strained layer 49 is stacked on the lower electrode 47. The strained layer 49 has a piezoelectric material, such as PZT or PLZT, in a range of 0.01 to 1.0 탆 using a sol-gel method, a sputtering method, or a chemical vapor deposition (CVD) method. Is formed to have a thickness of about 0.4 μm, and then subjected to heat treatment by rapid thermal treatment (RTA) to cause phase shift. The deformation layer 49 is deformed by an electric field generated between the upper electrode 51 and the lower electrode 47. In general, when the strained layer is laminated, the strained layer may not be evenly stacked because the thickness of the strained layer is changed according to the topology of the thin film stacked below. As a result, the strained layer may have defects, which may cause problems in the function of causing strain depending on the electric field. However, in the present invention, the first membrane 45a and the second membrane 45b are uniformly formed so that there is no step before the strain layer 49 is laminated, thereby smoothing the strain layer 49 formed thereon. The above problem can be eliminated by forming.

The upper electrode 51 is stacked on one side of the strained layer 49. The upper electrode 51 uses a metal such as aluminum, silver, or platinum, by sputtering method, from 0.01 to 1. It is formed to have a thickness of about 0㎛. A bias voltage is applied to the upper electrode 51 as a common electrode, and at the same time, the upper electrode 51 is used as a mirror reflecting the incident light beam. Therefore, when an image signal is applied to the lower electrode 47 and a bias voltage is applied to the upper electrode 51, an electric field is generated between the upper electrode 51 and the lower electrode 47. This deformation causes the deformation layer 49 to deform. Subsequently, the upper electrode 51, the deformable layer 49, and the lower electrode 47 are sequentially etched and patterned from an upper portion of the upper electrode 51.

Referring to FIG. 6D, the strained layer 49, the lower electrode 47, the first membrane 45a, and the second membrane (from the other side of the strained layer 49 using a conventional photolithography method) may be used. 45b), the etch stop layer 37, and the protective layer 35 are sequentially etched to form a via hole 55. Therefore, the via hole 55 is vertically formed from the other side of the strained layer 49 to the drain 33. Subsequently, a via contact 57 is formed in the via hole 55 by sputtering a metal having excellent electrical conductivity such as tungsten (W) or titanium (Ti). The via contact 57 is electrically connected to the drain 33 and the lower electrode 47. Therefore, the image signal is applied to the lower electrode 47 through the drain 33 and the via contact 57 from the transistor embedded in the active matrix 31. Subsequently, the second membrane 45b is patterned into predetermined pixel formation.

Referring to FIG. 6E, the sacrificial layer 39 is etched using hydrogen fluoride (HF) vapor to form an air gap 53, and then cleaned and dried to complete the actuator 32. Then, a rinse and dry treatment is performed to remove the remaining etching solution to complete the AMA device.

As described above, after completing the M × N thin film type AMA devices, a metal such as chromium (Cr), nickel (Ni), or gold (Au) is sputtered or evaporated using an active matrix 31. Is deposited at the bottom of the to form an ohmic contact (not shown). In addition, a bias (Tape Carrier Package) (not shown) bonding is applied to apply a bias voltage to a subsequent upper electrode 51, which is a common electrode, and an image signal to a lower electrode 47, which is a signal electrode. The active matrix 31 is cut to a predetermined thickness by using a conventional photolithography method. Subsequently, a photoresist layer (not shown) is formed on the pad of the AMA panel so that the pad of the AMA panel (not shown) has a sufficient height in preparation for TCP bonding. Subsequently, a portion of the photoresist layer on which the pad is formed is patterned to expose the pad of the AMA panel. Subsequently, the photoresist layer is etched using a dry etching method or a wet etching method, and the active matrix 31 is completely cut into a predetermined shape, and then the pad of the AMA panel and the pad of TCP are ACF (Anisotropic Conductive Film). (Not shown) to complete the manufacture of the thin film AMA module (module).

In the above-described thin film type optical path control device according to the present invention, the image signal transmitted through the pad of the TCP and the pad of the AMA panel is transmitted through the transistor, the drain 33 and the via contact 57 built in the active matrix 31. The lower electrode 47 is applied as a signal electrode. At the same time, a bias voltage is applied to the upper electrode 51, which is a common electrode, to generate an electric field between the upper electrode 51 and the lower electrode 47. The strained layer 49 between the upper electrode 51 and the lower electrode 47 causes deformation by this electric field. The strained layer 49 is contracted in a direction perpendicular to the electric field, and thus the actuator 32 is bent at a predetermined angle. The upper electrode 51, which also functions as a mirror that reflects the light beam, is formed on the actuator 32 so that the upper electrode 51 is inclined together with the actuator 32. Accordingly, the upper electrode 51 reflects the light beam incident from the light source at a predetermined angle, and the reflected light flux passes through the slit to form an image on the screen.

In the manufacturing method of the thin film type optical path control apparatus according to the present invention, the step of the sacrificial layer for forming the support of the actuator can be compensated by filling the membrane, so that the thin films of the subsequent process can be uniformly deposited. Therefore, since the actuator has the initial warpage without applying an electric field, the reflection angle of the light beam incident from the light source can be kept constant, thereby improving the light efficiency. In addition, by improving the flatness of the actuator, it is possible to make the stress between the thin films constituting the actuator uniform, thereby preventing deterioration of the actuator.

As described above, although described with reference to a preferred embodiment of the present invention, those skilled in the art will be variously modified without departing from the spirit and scope of the invention described in the claims below. And can be changed.

Claims (6)

Providing an active matrix having M × N transistors embedded therein and having a drain formed on one side thereof; Forming a sacrificial layer on top of the active matrix; Forming a first membrane on top of the sacrificial layer; Polishing the first membrane until the sacrificial layer is exposed; Forming a second membrane on top of the exposed sacrificial layer and first membrane; Forming a lower electrode on the second membrane; Forming a strained layer on the lower electrode; Forming an upper electrode on the strain layer; And And patterning the upper electrode, the strain layer, the lower electrode, and the membrane. The method of claim 1, wherein the forming of the sacrificial layer on the active matrix comprises: i) forming a protective layer on top of the active matrix and the drain, ii) forming an etch stop layer on the protective layer. Method of manufacturing a thin film type optical path control device, characterized in that carried out after the step. The method of claim 1, wherein the forming of the first membrane comprises forming a photoresist layer on top of the sacrificial layer, and patterning the photoresist layer and the sacrificial layer to form a drain below the sacrificial layer. A method of manufacturing a thin film type optical path control device, characterized in that it is carried out after exposing the formed portion. The method of claim 1, wherein the polishing of the first membrane is performed using a chemical mechanical polishing (CMP) method. The thin film type of claim 1, wherein the forming of the first membrane and the forming of the second membrane are performed by sputtering nitride or using a chemical vapor deposition (CVD) method. Method of manufacturing the optical path control device. The method of claim 1, wherein the patterning of the lower electrode comprises: forming a via hole vertically from the strained layer to the drain by etching the strained layer, the lower electrode, and the membrane from the other side of the strained layer; And forming a via contact for electrically connecting the drain and the lower electrode in the via hole.