KR19990004779A - Manufacturing method of thin film type optical path control device - Google Patents

Abstract

A method of manufacturing a thin film type optical path control device capable of preventing initial tilting of an actuator is disclosed. The method includes providing an active matrix having M × N transistors and having a drain pad, and iii) laminating a first layer on one side of the active matrix and parallel to the active matrix on the other side thereof. Ii) laminating a lower electrode layer on top of the first layer, iii) laminating a second layer on top of the lower electrode layer, iii) a second layer at a portion of the second layer in contact with the active matrix, Etching the second layer so that the thickness of the two layers and the thickness of the second layer in other portions are the same, iii) forming an upper electrode layer on the second layer, iii) patterning the upper electrode layer Forming an upper electrode, iii) patterning a second layer to form a strained layer, iii) patterning a lower electrode layer to form a lower electrode, and iii) patterning a first layer to form a support layer And forming an actuator having the steps: In order to reduce the step between the support part of the actuator and the other parts, the process of first etching the support part of the actuator among the deformation layers is introduced to solve the unevenness of the stress distribution due to the thickness difference of the deformation layer, thereby eliminating the initial tilting of the actuator. You can prevent it.

Description

Manufacturing method of thin film type optical path control device

The present invention relates to a method for manufacturing AMA (Actuated Mirror Arrays), which is a thin film type optical path control device, and more particularly, by reducing the step formed in the support portion of the actuator and other portions of the deformation layer, thereby preventing the initial tilt of the actuator. The manufacturing method of the thin film type optical path control apparatus which can improve the contrast of the image projected on a screen.

Optical path control devices or spatial light modulators for projecting optical energy onto a screen may be applied to various fields such as optical communication, image processing, and information display devices. The image processing apparatus using the optical path adjusting device or the spatial light modulator typically has a direct-view image display device and a projection-type image device according to a method of displaying optical energy on a screen. display device).

An example of a direct-view image display device is a CRT (Cathode Ray Tube). The CRT device is called a CRT, which has excellent image quality but increases in weight and volume as the screen is enlarged, leading to an increase in manufacturing cost. There is. Projection type image display devices include a liquid crystal display (LCD), a deformable mirror device (DMD), and an AMA. Such projection image display devices can be further divided into two groups according to their optical characteristics. That is, devices such as LCDs can be classified as transmissive spatial light modulators, while DMD and AMA can be classified as reflective spatial light modulators.

Transmission optical modulators, such as LCDs, have a very simple optical structure, which makes them thinner, lighter in weight, and smaller in volume. However, due to the polarity of the light, the light efficiency is low, there is a problem inherent in the liquid crystal material, for example, there is a disadvantage that the response speed is slow and the inside is easy to overheat. In addition, the maximum light efficiency of existing transmission light modulators is limited to a range of 1-2%, requiring dark room conditions to provide acceptable display quality. Therefore, optical modulators such as DMD and AMA have been developed to solve the above problems.

Although DMD shows a relatively good light efficiency of about 5%, the hinge structure employed in the DMD not only causes serious fatigue problems, but also requires a very complicated and expensive driving circuit. In the AMA, each of the mirrors installed therein reflects light incident from the light source at a predetermined angle, and the reflected light is projected on the screen through an aperture such as a slit or a pinhole. It is a device that can adjust the speed of light to form an image. Therefore, its structure and operation principle are simple, and high light efficiency (more than 10% light efficiency) can be obtained compared to LCD or DMD. In addition, contrast can be improved to obtain a bright and clear image.

Each actuator of the AMA generates a deformation in accordance with the electric field generated by the electrical first signal (image signal) and the second signal (bias signal) applied. As the actuator deforms, each of the mirrors mounted thereon is tilted. Accordingly, the inclined mirrors reflect light incident from the light source at a predetermined angle to form an image on the screen. 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. The actuator can also be configured as a warping material such as PMN (Pb (Mg, Nb) O ₃ ).

These AMA devices are largely divided into bulk type and 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 adjusting device is made by thinly cutting a multilayer ceramic to mount a ceramic wafer having a metal electrode formed therein in an active matrix in which a transistor is embedded, and then processing by a sawing method and installing a mirror thereon. However, the bulk optical path control device requires very high precision in design and manufacture, and has a disadvantage in that the response of the deformable part is slow.

Accordingly, 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 Patent Application No. 96-42197 (name of the invention: thin film type optical path control device which can control the stress of a membrane and a method of manufacturing the same) filed on September 24, 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.

1 and 2, the thin film type optical path control apparatus includes an active matrix 41 having a drain pad 49 formed on one side thereof, and an actuator 43 formed on the active matrix 41.

An active matrix 41 having M × N (M and N are integers) metal oxide semiconductor (MOS) transistors (not shown) is stacked on top of the active matrix 41 and the drain pad 49. The protective layer 51 and the etch stop layer 53 stacked on the protective layer 51 is included.

One side of the actuator 43 is in contact with a portion of the etch stop layer 53 in which the drain pad 49 is formed, and the other side thereof is parallel to the lower portion of the active matrix 41 through the air gap 55. A membrane 57 having a cross section formed, a lower electrode 61 stacked on top of the membrane 57, a strained layer 63 stacked on top of the lower electrode 61, and stacked on top of the strained layer 63. The upper electrode 65 includes the via contact 69 formed to electrically connect the lower electrode 61 and the drain pad 49 to each other.

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

3A to 3D are manufacturing process diagrams of the apparatus shown in FIG. 2. 3A to 3D, the same reference numerals are used for the same members as in FIG.

Referring to FIG. 3A, Phosphor-Silicate Glass (PSG) is formed on an active matrix 41 having M × N transistors (not shown) and a drain pad 49 formed on one side thereof. The protective layer 51 is laminated. The protective layer 51 is formed using a chemical vapor deposition (CVD) method. The protective layer 51 protects the active matrix 41 from subsequent processes.

An etch stop layer 53 made of nitride is stacked on the passivation layer 51. The etch stop layer 53 is formed using a low pressure chemical vapor deposition (LPCVD) method. The etch stop layer 53 prevents the protective layer 51, the active matrix 41, and the like from being etched during the subsequent etching process. The sacrificial layer 56 is stacked on the etch stop layer 53. The sacrificial layer 56 is formed of phosphorous silicate glass (PSG) having a high concentration of phosphorus (PG) by using an atmospheric pressure chemical vapor deposition (APCVD) method. In this case, since the sacrificial layer 56 covers the upper portion of the active matrix 41 in which the transistors are embedded, the flatness of the surface thereof is very poor. Accordingly, the surface of the sacrificial layer 56 is planarized by using a spin on glass (SOG) method or a chemical mechanical polishing (CMP) method. Subsequently, a portion of the sacrificial layer 56 in which the drain pad 49 is formed is etched to expose a portion of the etch stop layer 53.

Referring to FIG. 3B, the membrane 57 is stacked on top of the exposed etch stop layer 53 and on top of the sacrificial layer 56. The membrane 57 is formed of silicon carbide at a temperature of 200-300 ° C. using a Plasma Enhanced CVD (PECVD) method. At this time, the silicon carbide is prepared by depositing silicon (Si) and carbon (C) generated from the liquid (liquid) C ₆ H ₁₈ Si ₂ . In addition, the silicon carbide may be prepared by depositing Si and C generated from a mixture of SiH ₄ and CH ₄ . Subsequently, the membrane 57 made of silicon carbide is heat-treated at a temperature of 600 ° C. or lower to adjust the stress in the membrane 57.

A lower electrode 61 made of a metal such as platinum (Pt) or tantalum (Ta) is stacked on the membrane 57. The lower electrode 61 is formed using a sputtering method. The first signal is applied to the lower electrode 61, which is a signal electrode, through the transistor, the drain pad 49, and the via contact 69 embedded in the active matrix 41. Subsequently, Iso 전극 Cutting of the lower electrode 61 is performed to short-circuit the signal applied to the lower electrode 61.

Referring to FIG. 3C, a strain layer 63 made of a piezoelectric material such as PZT or PLZT is formed on the lower electrode 61. The strained layer 63 is formed using a sol-gel method, and then thermally transformed by rapid thermal annealing (RTA) to phase change. The strained layer 63 is deformed by an electric field generated between the upper electrode 65 and the lower electrode 61. The upper electrode 65 is stacked on top of the strained layer 63. The upper electrode 65 is formed of a metal having excellent electrical conductivity and reflectivity, such as aluminum or platinum, using a sputtering method. The second signal is applied to the upper electrode 65 through a common electrode line (not shown) to generate an electric field between the lower electrode 61 and the upper electrode 65. In addition, the upper electrode 65 also functions as a mirror that reflects light incident from the light source. Subsequently, the upper electrode 65 is patterned into a predetermined pixel shape and a stripe 67 is formed in the center of the upper electrode 65. The stripe 67 operates the upper electrode 65 uniformly to prevent diffuse reflection of incident light.

Referring to FIG. 3D, after the strained layer 63 and the lower electrode 61 are patterned into a pixel shape having the same shape as the upper electrode 65, the drain pad 49 is formed from an upper portion of one side of the strained layer 63. The strain layer 63, the lower electrode 61, the membrane 57, the etch stop layer 53, and the passivation layer 51 are sequentially etched to the upper portion, and the via hole is formed from the strain layer 63 to the drain pad 49. Form 68. Subsequently, a via contact 69 is formed inside the via hole 68 such that the drain pad 49 and the lower electrode 61 are electrically connected to each other by a metal such as tungsten, platinum, or titanium. do. Thus, the via contact 69 is formed vertically from the lower electrode 61 to the top of the drain pad 49 in the via hole 68. Therefore, the first signal is applied to the lower electrode 61 through the transistor, the drain pad 49, and the via contact 69 embedded in the active matrix 41 from the outside. Subsequently, after the membrane 57 is patterned to have a predetermined pixel shape, the sacrificial layer 56 is etched with hydrogen fluoride (HF) vapor and washed and dried to complete a thin film type AMA device.

In the above-described thin film type optical path adjusting device, the first signal applied from the outside is applied to the lower electrode 61 through the MOS transistor, the drain pad 49, and the via contact 69 embedded in the active matrix 41. In addition, a second signal is applied to the upper electrode 65 from the outside through the common electrode line to generate an electric field between the upper electrode 65 and the lower electrode 61. Due to this electric field, the strain layer 63 stacked between the upper electrode 65 and the lower electrode 61 causes deformation. The strained layer 63 contracts in a direction perpendicular to the electric field, and the actuator 43 including the strained layer 63 actuates upward at a predetermined angle. Therefore, the upper electrode 65 on the actuator 43 also inclines in the same direction. Light incident from the light source is reflected by the upper electrode 65 inclined at a predetermined angle, and then projected onto a screen to form an image.

In the thin film type optical path adjusting device described in the foregoing application, since the strained layer is formed using the sol-gel method, a large step is generated between the supporting portion of the actuator and the other portions. That is, shrinkage of the strained layer occurs when the strained layer is formed by using the sol-gel method and then heat treated. After shrinkage of the deformable layer, since the thickness of the deformed layer of the support portion of the actuator is formed thicker than the thickness of the other portion, a lot of stress is accumulated in the support portion of the actuator. Due to such an imbalance in the stress distribution, there is a problem that the actuator is inclined upward even when the first signal is not applied. This initial tilting of the actuator has a non-uniform value per actuator as a whole. Accordingly, the reflection angle of the upper electrode on the actuator cannot be kept constant, resulting in a problem that the contrast of the image reflected by the upper electrode and projected onto the screen is lowered.

Accordingly, an object of the present invention is to provide a method of manufacturing a thin film type optical path control apparatus capable of preventing the initial tilt of the actuator by uniformly distributing the stress distribution of the strained layer by reducing the step at the supporting portion of the actuator and other portions of the strained layer. To provide.

1 is a plan view of a membrane of a previously applied thin film optical path control device.

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

3A to 3D are manufacturing process diagrams of the apparatus shown in FIG. 2.

Figure 4 is a plan view of the support layer of the 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 6F are manufacturing process diagrams of the apparatus shown in FIG. 4.

<Explanation of symbols for main parts of drawing>

100: active matrix 105: drain pad

110: protective layer 115: etching prevention layer

120: sacrificial layer 125: support layer

130: lower electrode 135: strained layer

140: upper electrode 145: empty hole

150: free contact 155: stripe

160: air gap 200: actuator

In order to achieve the above object, the present invention provides a step of providing an active matrix in which M x N (M, N is an integer) transistor and a drain pad formed on one side thereof, and forming an actuator on the active matrix. It provides a method of manufacturing a thin film type optical path control device comprising. The forming of the actuator may include: (i) stacking a first layer such that one side is in contact with the top of the active matrix and the other side is parallel to the active matrix; ii) stacking a lower electrode layer on top of the first layer. (I) laminating a second layer on top of the lower electrode layer, iii) a thickness of the second layer in a portion of the second layer in contact with the active matrix, and a second layer in other portions. Etching the second layer so that the thicknesses of the two layers are the same; iii) forming an upper electrode layer on top of the second layer, iv) patterning the upper electrode layer to form an upper electrode, iii) the Patterning a second layer to form a strained layer, iii) patterning the lower electrode layer to form a lower electrode, and iii) patterning the first layer to form a support layer And forming a radiator.

In the thin film type optical path adjusting device according to the present invention, the first signal applied from the outside is applied to the lower electrode through the transistor, the drain pad, and the via contact embedded in the active matrix. In addition, a second signal is applied to the upper electrode through the common electrode line from the outside to generate an electric field between the upper electrode and the lower electrode. Due to this electric field, the strain layer formed between the upper electrode and the lower electrode causes deformation. The strained layer contracts in a direction perpendicular to the generated electric field, and the actuator including the strained layer is bent at a predetermined angle. Therefore, the upper electrode on the actuator is also inclined in the same direction. Light incident from the light source is reflected by the upper electrode inclined at a predetermined angle as described above, and then is projected onto a screen to form an image.

Therefore, according to the manufacturing method of the thin film type optical path control apparatus according to the present invention, in order to reduce the step difference between the support portion of the actuator and other portions, by introducing a step of first etching the support portion of the actuator of the deformation layer, The nonuniformity of the stress distribution due to the thickness difference can be solved. As a result, the initial tilt of the actuator can be prevented to improve the contrast of the image projected on the screen.

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 support layer of the thin film type optical path control 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 device according to the present invention includes an active matrix 100 having M × N MOS transistors (not shown) and an actuator 200 formed on the active matrix 100. ).

The active matrix 100 extends from the drain region of the transistor so that the drain pad 105, the drain pad 105, and the protection layer 110 formed on the active matrix 100 are formed on one side of the active matrix 100. And an etch stop layer 115 formed on the protective layer 110.

The actuator 200 has one side in contact with the etch stop layer 115 and the other side has a cross section formed in parallel with a lower portion of the active matrix 100 via an air gap 160, and a support layer 125. ), A lower electrode 130 formed on the upper side, a strained layer 135 formed on the lower electrode 130, an upper electrode 140 formed on the strained layer 135, and one side of the strained layer 135. The lower electrode in the via hole 145 formed from the strained layer 135, the lower electrode 130, the support layer 125, the etch stop layer 115, and the protective layer 110 to an upper portion of the drain pad 105. And a via contact 150 formed to connect the 130 and the drain pad 105.

In addition, referring to Figure 4, the plane of the support layer 125, one side has a concave portion of the rectangular shape in the center, the concave portion is formed in a shape that widens stepwise toward both edges, the other side is Corresponding to the concave portion has a quadrangular protrusion that narrows stepwise toward the center portion. Therefore, the protruding portion of the support layer of the actuator adjacent to the concave portion of the support layer 125 is fitted, and the rectangular projection is fitted into the concave portion of the support layer of the adjacent actuator. The support layer 125 of the present invention performs the function of the membrane 57 described in the preceding application.

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 6F show a manufacturing process diagram of the thin film type optical path control device shown in FIG. 6A to 6F, the same reference numerals are used for the same members as in FIG.

Referring to FIG. 6A, a drain pad 105 is formed on an active matrix 100 in which M × N MOS transistors (not shown) are embedded. The drain pad 105 is formed to have a thickness of about 4000 mm by using a metal such as tungsten or titanium. The drain pad 105 is applied from the outside to transfer the first signal transmitted through the MOS transistor embedded in the active matrix 100 to the via contact 150.

Subsequently, a protective layer 110 is formed on the drain pad 105 and the active matrix 100 to protect the active matrix 100 having the transistor embedded therein. The protective layer 110 is formed of phosphorous silicate glass (PSG) using a chemical vapor deposition (CVD) method. It is formed to have a thickness of about 0㎛. The protective layer 110 prevents the transistor embedded in the active matrix 100 from being damaged during subsequent processing.

An etch stop layer 115 is stacked on the passivation layer 110. The etch stop layer 115 is formed to have a thickness of about 1000 to 2000 GPa using nitride by low pressure chemical vapor deposition (LPCVD). The etch stop layer 115 prevents the active matrix 100 and the protective layer 110 from being etched due to a subsequent etching process.

The sacrificial layer 120 is stacked on the etch stop layer 115. The sacrificial layer 120 is formed of phosphorus silicate glass (PSG) containing phosphorus (P) in a high concentration so as to have a thickness of about 2.0 to 3.0 μm by an atmospheric chemical vapor deposition (APCVD) method. In this case, since the sacrificial layer 120 covers the upper portion of the active matrix 100 in which the transistor is embedded, the flatness of the surface thereof is very poor. Therefore, the surface of the sacrificial layer 120 is made to have a thickness of about 1 μm by using a spin on glass (SOG) method or a CMP method on the surface of the sacrificial layer 120. It is flattened by grinding. Subsequently, a portion of the sacrificial layer 120 in which the drain pad 105 is formed is etched to expose a portion of the etch stop layer 115 to form a position where the support of the actuator 200 is to be formed.

6B is a view illustrating a state in which the second layer 134 is formed. FIG. 6C is an enlarged view of a portion 'C' of FIG. 6B.

Referring to FIG. 6B, the first layer 124 is stacked on the exposed etch stop layer 115 and the sacrificial layer 120. The first layer 124 is formed to have a thickness of about 0.1 to 1.0 μm using a low pressure chemical vapor deposition (LPCVD) method. The first layer 124 is later patterned into a support layer 125.

The lower electrode layer 129 is formed on the first layer 124 using a metal such as platinum, tantalum, or platinum-tantalum having excellent electrical conductivity. The lower electrode layer 129 is formed to have a thickness of about 0.01 to 1.0 µm using a sputtering method. Subsequently, the lower electrode layer 129 is iso-cutted so that the lower electrode layer 129 is applied with an independent first signal for each pixel. The lower electrode layer 129 is later patterned with the lower electrode 130 to which the first signal is applied. The first signal applied from the outside is applied to the lower electrode 130 through the transistor, the drain pad 105, and the via contact 150 embedded in the active matrix 100.

The second layer 134 is stacked on the lower electrode layer 130. The second layer 134 is formed using a piezoelectric material such as PZT or PLZT to have a thickness of 4000 to 6000 kPa, preferably about 4000 kPa. The second layer 134 may be formed using a sol-gel method, a sputtering method, or a chemical vapor deposition (CVD) method. In the present invention, the second layer 134 is formed by using a sol-gel method, and then thermally shifted using a rapid heat treatment (RTA) method to phase change. Subsequently, the piezoelectric material constituting the second layer 134 is polarized. The second layer 134 is later patterned into the strained layer 135.

Referring to FIG. 6C, since the second layer 134 is formed using the sol-gel method, the supporting portion of the actuator of the second layer 134 is formed thicker than other portions. That is, when the second layer 134 is formed to have a thickness of about 4000 mm (d ₂ ), the second layer at the support portion of the actuator is about 1.0 μm thick (d ₁ + d _2). Thickness). Therefore, due to the difference in the thickness of the stacked second layer 134, a lot of stress is accumulated in the support portion of the actuator. Due to such an imbalance in the stress distribution, there is a problem that the actuator is inclined upward even when the first signal is not applied.

Therefore, as shown in FIG. 6D, in the present invention, the supporting portion of the actuator of the second layer 134 is etched about 5000 to 6000 kPa, and the thickness of the second layer 134 of the portion is about 4000 to 5000 kPa. Be sure to Therefore, since the thickness of the second layer 134 can be formed uniformly, an imbalance in the stress distribution can be eliminated, and initial tilting of the actuator can be prevented.

Referring to FIG. 6E, an upper electrode layer 139 is stacked on the second layer 134. The upper electrode layer 139 is formed of a metal having electrical conductivity and reflectivity such as aluminum, silver, or platinum so as to have a thickness of about 0.01 to 1.0 탆 using a sputtering method. Subsequently, the upper electrode layer 139 is patterned to form an upper electrode 140 having a predetermined pixel shape. At this time, one side of the upper electrode 140, when the actuator 200 causes deformation, the upper electrode 140 is uniformly operated so that the light incident from the light source (not shown) to prevent the diffuse reflection ( 155 are formed together. The second signal is applied to the upper electrode 140 through a common electrode line (not shown) from the outside.

Subsequently, the second layer 134 is patterned to form a strained layer 135 having a pixel shape larger than that of the upper electrode 140. Subsequently, the lower electrode layer 129 is patterned to form a lower electrode 130 having a pixel shape larger than that of the strained layer 135. When the second signal is applied to the upper electrode 145 and the first signal is applied to the lower electrode 135, an electric field is generated between the upper electrode 145 and the lower electrode 135. The deformation layer 140 causes deformation by this electric field.

Subsequently, the strained layer 135, the lower electrode 130, the first layer 124, the etch stop layer 115, and the protective layer 110 from one side of the strained layer 135 to an upper portion of the drain pad 105. The via holes are sequentially etched to form via holes 145. Accordingly, the via hole 145 is formed from one side of the strained layer 135 to an upper portion of the drain pad 105. Subsequently, a via contact 150 is formed by depositing a metal having excellent electrical conductivity such as tungsten (W), aluminum, or titanium (Ti) in the via hole 145 using a sputtering method. The via contact 150 electrically connects the drain pad 105 and the lower electrode 130. Therefore, the first signal applied from the outside is applied to the lower electrode 130 through the transistor, the drain pad 105, and the via contact 150 embedded in the active matrix 100. Subsequently, the support layer 125 is patterned into a predetermined pixel shape.

Referring to FIG. 6F, the sacrificial layer 120 is etched using hydrogen fluoride (HF) vapor to form an air gap 160, and then a rinse and dry process is performed to rinse the AMA device. Complete

In the above-described thin film type optical path control device according to the present invention, the first signal transmitted from the outside is a lower electrode (signal electrode) through the transistor, the drain pad 105 and the via contact 150 built in the active matrix 100 ( 130). At the same time, a second signal is applied to the upper electrode 140 through the common electrode line to generate an electric field between the upper electrode 140 and the lower electrode 130. Due to this electric field, the deformation layer 135 formed between the upper electrode 140 and the lower electrode 130 causes deformation. The deformation layer 135 is contracted in a direction orthogonal to the electric field, whereby the actuator 200 is bent upward at a predetermined angle. Since the upper electrode 140, which also functions as a mirror that reflects the light beam, is formed on the actuator 200, the upper electrode 140 is inclined together with the actuator 200. Accordingly, the upper electrode 140 reflects the light incident from the light source at a predetermined angle, and the reflected light 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, in order to reduce the step difference between the support portion of the actuator and other portions, by introducing a process of first etching the support portion of the actuator of the deformation layer, the thickness difference of the deformation layer It can eliminate the nonuniformity of stress distribution caused by. As a result, the initial tilt of the actuator can be prevented to improve the contrast of the image projected on the screen.

Moreover, since the step difference between the support portion of the actuator and the other portions can be reduced, it is possible to prevent the lower electrode from being damaged by excessive etching when patterning the strained layer into a predetermined pixel shape.

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

Claims (2)

Providing an active matrix having M × N (M, N is an integer) transistors and a drain pad formed at one side thereof; And Iii) laminating a first layer in contact with an upper side of the active matrix and the other side parallel to the active matrix, ii) laminating a lower electrode layer on top of the first layer, iii) of the lower electrode layer Stacking a second layer thereon; i) so that the thickness of the second layer in the portion where the first layer is in contact with the active matrix of the second layer and the thickness of the second layer in the other portion are the same; Etching the second layer, iii) forming an upper electrode layer on top of the second layer, iii) patterning the upper electrode layer to form an upper electrode, iii) patterning the second layer and deforming layer Forming an actuator by patterning the lower electrode layer, and iii) forming a support layer by patterning the first layer. Process for producing a film-like optical path control device. The method of claim 1, wherein etching the portion of the second layer in contact with the active matrix comprises etching 5000 to 6000 μs in a portion of the second layer, wherein the first layer contacts the active matrix. The manufacturing method of the thin film type optical path control device characterized in that it is a step.