KR100251110B1 - Manufacturing method of ama - Google Patents

Abstract

PURPOSE: A method for manufacturing a thin film type light road controller is provided to reduce a crack of a strain layer generated from a supporting unit of an actuator by reducing a layer difference of a supporting unit of an actuator and controlling an inclination. CONSTITUTION: The first photoresist is coated on a sacrifice layer(120) to form a supporting unit of an actuator(200). An opening is formed in the first photoresist with patterning the first photoresist. A drain pad in the sacrifice layer(120) is firstly etched to a specific depth using the first photoresist as the fist mask. The second photoresist is coated on the first etched sacrifice layer(120). An etching preventing layer(115) is partly exposed with secondly etching inside of the first etched sacrifice layer using the second photoresist as the second mask. The third photoresist is coated on the sacrifice layer etched as a stair shape. An opening larger than the first mask is formed in the third photoresist with patterning the third photoresist.

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. More specifically, a sacrificial layer is patterned by a two-step process to provide a step between a portion at which the support portion of the actuator is to be formed and other portions thereof. The present invention relates to a method for manufacturing a thin film type optical path control apparatus that facilitates slope control of a support and prevents cracking of a deformation layer due to a step and a slope of the support.

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, the contrast of the image projected on the screen is 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 applied electric picture signal and the bias signal. 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. In addition, the actuator may be formed 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. Such a thin film type optical path adjusting device is disclosed in Patent Application No. 96-42197 (name of the invention: thin film type optical path adjusting device which can control the stress of a membrane and a method of manufacturing the same) which the applicant has applied for a patent on September 24, 1996. have.

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

1 and 2, the thin film type optical path control apparatus includes an active matrix 1 having a drain pad 5 formed on one side thereof and an actuator 60 formed on the active matrix 1.

The active matrix 1 having an M × N metal oxide semiconductor (MOS) transistor (not shown) and having a drain pad 5 is disposed on top of the active matrix 1 and the drain pad 5. The stacked protective layer 10 and the etch stop layer 15 stacked on the protective layer 10 is included.

The actuator 60 includes a membrane 25 having a cross section stacked parallel to a lower portion of the active matrix 1, a lower electrode 30 stacked on the membrane 25, and an upper portion of the lower electrode 30. The strain contact layer 35 formed on the strain layer 35, the upper electrode 40 stacked on the strain layer 35, and the lower electrode 30 and the drain pad 5 are electrically connected to each other. It includes.

Referring to FIG. 1, one side of a plane of the membrane 25 has a rectangular concave portion at a central portion thereof, and the concave portion is formed in a stepped shape toward both edges. The other side of the plane of the membrane 25 has a rectangular protrusion that narrows stepwise toward the central portion corresponding to the concave portion. Therefore, the protrusion of the membrane of the actuator adjacent to the concave portion of the membrane 25 is fitted, and the rectangular protrusion is fitted to the concave portion of the membrane of the adjacent actuator.

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, a protective layer 10 including MxN transistors (not shown) and made of Phosphor Silicate Glass (PSG) on top of an active matrix 1 having a drain pad 5 is provided. )). The protective layer 10 is formed to have a thickness of about 1.0 to about 2.0 μm using a chemical vapor deposition (CVD) method. The protective layer 10 protects the active matrix 1 in which the transistor is embedded during subsequent processing.

The etch stop layer 15 is stacked on the passivation layer 10 by using nitride. The etch stop layer 15 is formed to have a thickness of about 2000 kPa using a low pressure chemical vapor deposition (LPCVD) method. The etch stop layer 15 prevents the protective layer 10 and the active matrix 1 from being etched and damaged during the subsequent etching process.

The sacrificial layer 17 is stacked on the etch stop layer 10. The sacrificial layer 17 is formed of phosphorous silicate glass (PSG) having a high concentration of phosphorus (PG) so as to have a thickness of about 1.0 to 3.0 μm using the Atmospheric Pressure Vapor Deposition (APCVD) method. Form. In this case, since the sacrificial layer 17 covers the upper portion of the active matrix 1 in which the transistor is embedded, the flatness of the surface thereof is very poor. Accordingly, the surface of the sacrificial layer 17 is planarized by using a spin on glass (SOG) method or a chemical mechanical polishing (CMP) method. Next, a portion of the sacrificial layer 17 in which the drain pad 5 is formed is etched to expose a portion of the etch stop layer 15.

Referring to FIG. 3B, the membrane layer 24 is stacked on the exposed etch stop layer 15 and on the sacrificial layer 17 to have a thickness of about 0.1 to 1.0 μm. The membrane layer 24 is formed of silicon carbide at a temperature of 200 to 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 . Alternatively, the silicon carbide may be prepared by depositing silicon and carbon generated from a mixture of SiH ₄ and CH ₄ . Subsequently, the membrane layer 24 made of silicon carbide is heat-treated at a temperature of 600 ° C. or lower to adjust the stress in the membrane layer 24.

The lower electrode layer 29 is stacked on the membrane layer 24 using a metal such as platinum (Pt) or tantalum (Ta). The lower electrode layer 29 is formed to have a thickness of about 500 to 2000 mW using a sputtering method. The lower electrode layer 29 is later patterned into the lower electrode 30. Subsequently, Iso­Cutting is performed to separate the lower electrode layer 29 for each pixel.

Referring to FIG. 3C, the first layer 34 is formed on the lower electrode layer 29 using a piezoelectric material such as PZT or PLZT. The first layer 34 is formed to have a thickness of about 0.1-1 .0 μm, preferably about 0.4 μm by using a sol-gel method, and then rapid thermal Annealing: Heat transfer by RTA). The first layer 34 is later patterned into a strained layer 35. The upper electrode layer 39 is stacked on top of the first layer 34. The upper electrode layer 39 is formed of a metal having excellent electrical conductivity and reflectivity such as aluminum or platinum so as to have a thickness of about 500 to 2000 kPa using a sputtering method. The upper electrode layer 39 is later patterned into the upper electrode 40.

Referring to FIG. 3D, after applying a photoresist (not shown) on the upper electrode layer 39, the upper electrode layer 39 is patterned into a predetermined shape to form the upper electrode 40. The second electrode (bias signal) is applied to the upper electrode 40 from a common electrode line (not shown). At the same time, the upper electrode 40 also serves as a mirror for reflecting light incident from a light source (not shown). When the upper electrode layer 39 is patterned as described above, stripes 55 are formed together at the center of the upper electrode 40. When the actuator 60 causes deformation, the stripe 55 uniformly bends the upper electrode 40 to prevent diffuse reflection of the light beam incident from the light source.

Subsequently, the strained layer 35 and the lower electrode 30 are formed using the same method as the method of patterning the first electrode 34 and the lower electrode layer 29 to the upper electrode layer 39. The first electrode (image signal) is applied to the lower electrode 30 through the MOS transistor from the outside. Subsequently, the strained layer 35, the lower electrode 30, the membrane layer 24, the etch stop layer 15, and the protective layer 10 are sequentially disposed from one side of the strained layer 35 to the top of the drain pad 5. The via hole 43 is formed from the strained layer 35 to the drain pad 5 by etching. Subsequently, a via contact 50 is formed to electrically connect the drain pad 5 and the lower electrode 30 to a metal such as tungsten (W), platinum, or titanium using a sputtering method. Thus, the via contact 50 is formed vertically from the lower electrode 30 to the drain pad 5 in the via hole 45. Therefore, the first signal transmitted from the transistor embedded in the active matrix 1 is applied to the lower electrode 30 through the drain pad 5 and the via contact 50. After the membrane layer 24 is patterned to form the membrane 25, the sacrificial layer 17 is etched with hydrogen fluoride (HF) vapor, washed and dried to complete an AMA device.

In the above-described thin film type optical path adjusting device, the first signal (image signal) transmitted from the transistor embedded in the active matrix 1 is applied to the lower electrode 30 through the drain pad 5 and the via contact 50. . In addition, a second signal (bias signal) is applied to the upper electrode 40 to generate an electric field between the upper electrode 40 and the lower electrode 30. By this electric field, the deformation layer 35 formed between the upper electrode 40 and the lower electrode 30 causes deformation. The deformation layer 35 causes deformation in a direction perpendicular to the electric field, and the actuator 60 including the deformation layer 35 is bent upward. Therefore, the upper electrode 40 on the actuator 60 is also bent in the same direction. The light beam incident from the light source is reflected by the upper electrode 40 bent at a predetermined angle, and then is projected onto the screen to form an image.

However, in the thin film type optical path adjusting device described in the preceding application, a portion of the sacrificial layer is etched to form the supporting portion of the actuator, so that a step occurs in the portion where the supporting portion of the actuator is to be formed and other portions thereof. Therefore, when the strained layer is formed on the sacrificial layer by using the sol-gel method, the support portion of the strained layer may be formed due to a step and an inclination between the portion where the sacrificial layer is etched below the portion of the strained layer (support portion) and other portions. Cracks occur in the part. That is, when etching a portion of the sacrificial layer, since one pattern is patterned in one step, slope control of a portion of the sacrificial layer under cut or etching is not easy. Therefore, cracks are liable to occur in the deformed layer formed on the portion where the sacrificial layer is etched (the support of the actuator) among the subsequently formed deformable layers, and once the crack is generated, the crack is accelerated while the actuator is driven to There is a problem that it is difficult to perform a smooth operation depending on the signal applied.

Accordingly, an object of the present invention is to pattern the sacrificial layer by a two-step process to reduce the step difference between the portion where the support portion of the actuator is to be formed and other portions, thereby facilitating the inclination adjustment of the support portion, and the step height of the support portion. And a method for producing a thin film type optical path control device capable of preventing cracks in a strained layer due to inclination.

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

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 6D are cross-sectional views illustrating a method of manufacturing the device shown in FIG. 5.

7A to 7C are cross-sectional views taken along line B′B ′ of the apparatus shown in FIG. 4 for explaining the step of forming the support of the actuator.

<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 having a drain pad formed on one side of the M × N transistors, iii) forming a sacrificial layer on top of the active matrix and the drain pad Step, ii) after applying the first photoresist on the sacrificial layer, first etching the portion of the sacrificial layer formed with the drain pad below using the first photoresist as a first mask, And iv) applying a second photoresist on the sacrificial layer, and then secondly etching the inside of the first etched portion of the sacrificial layer using the second photoresist as a second mask to expose the active matrix. Forming a support of the actuator, and on top of the exposed active matrix and the sacrificial layer Forming a support layer, forming a lower electrode on the support layer, forming a strain layer on the lower electrode, forming an upper electrode on the strain layer, and the lower electrode and the It provides a method of manufacturing a thin film type optical path control device comprising the step of forming an actuator consisting of forming a via contact connecting the drain pad.

In the thin film type optical path adjusting device according to the present invention, the first signal (image 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 (bias signal) is applied to the upper electrode 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 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. The 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 the 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 and adjust the inclination of the actuator support, forming a sacrificial layer and then first etching the sacrificial layer using a first mask, By using a second mask having a smaller size than the first mask, the step of secondary etching the inside of the primary-etched sacrificial layer and the step of finally wet etching the sacrificial layer, by introducing a step of the support portion of the actuator Since the slope of the support can be smoothly formed by reducing the inclination, the crack of the deformed layer generated in the actuator support can be reduced.

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 the etch stop layer 115 via an air gap 160, and a support layer 125. A lower electrode 130 formed at an upper portion of the lower electrode 130, a strained layer 135 formed at an upper portion of the lower electrode 130, an upper electrode 140 formed at an upper portion of the strained layer 135, and one side of the strained layer 135. The lower electrode may be formed in the via hole 145 formed to the upper portion of the drain pad 105 through the strained layer 135, the lower electrode 130, the support layer 125, the etch stop layer 115, and the protective layer 110. 130 and the via contact 150 formed to connect 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 25 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 6D are cross-sectional views illustrating a method of manufacturing the device shown in FIG. 5. 6A to 6D, 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 0.1-1. 1 phosphorus 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 planarized using a spin on glass (SOG) method or a CMP method. Subsequently, a portion of the sacrificial layer 120 where the drain pad 105 is formed is etched to expose a portion of the etch stop layer 115, thereby forming a position at which the support portion of the actuator 200 is to be formed.

7A to 7C are cross-sectional views taken along line B′B ′ of the apparatus shown in FIG. 4 to explain the step of forming the support of the actuator.

Referring to FIG. 7A, in order to form a support part of the actuator 200, after applying a first photoresist (not shown) on the sacrificial layer 120, the first photoresist is patterned to form the support. 1 An opening is formed in the photoresist. Subsequently, a portion of the sacrificial layer 120 having the drain pad formed thereon is first etched to a predetermined depth by using the first photoresist as a first mask. In this case, in order to form the slope of the portion to be etched slowly in the sacrificial layer 120, the etching time may be extended to deeply control the etching depth, and in order to form the slope of the portion to be etched more rapidly, the etching time may be shorter to form the etching. The depth can be adjusted thinly.

Referring to FIG. 7B, after applying a second photoresist (not shown) on the sacrificial layer 120 firstly etched using the first photoresist, the second photoresist is patterned to form the second photoresist. An opening having a smaller size than the first mask is formed in the photoresist. Subsequently, the inside of the first etched portion of the sacrificial layer is secondly etched using the second photoresist as a second mask to expose a portion of the etch stop layer 115. Therefore, the sacrificial layer 120 etched as the first and second as described above has a step shape.

Referring to FIG. 7C, after applying a third photoresist (not shown) on the sacrificial layer 120 etched in a step shape, the third photoresist is patterned to form the first photoresist on the third photoresist. An opening larger in size than the mask is formed. Subsequently, using the third photoresist as a third mask, the sacrificial layer 120 of the stepped portion as described above is etched so that the stepped sacrificial layer 120 has a gentle curved shape. do. In this case, preferably, the sacrificial layer 120 is etched using a wet etching method.

Conventionally, a portion of the sacrificial layer is etched to form a support portion of the actuator, whereby a step is generated in a portion where the support portion of the actuator is to be formed and other portions thereof. Therefore, when the strained layer is formed on the sacrificial layer by using the sol-gel method, the support portion of the strained layer may be formed due to a step and an inclination between the portion where the sacrificial layer is etched below the portion of the strained layer (support portion) and other portions. Cracks occur in the part. That is, when etching a portion of the sacrificial layer, since one pattern is patterned in one step, it is not easy to adjust the inclination of the portion where the portion of the sacrificial layer is undercut or etched. It is easy to cause cracks in the deformed layer formed on the portion where the sacrificial layer is etched (support of the actuator), and once the crack is generated, the crack is accelerated while the actuator is driven, and thus it is difficult to perform a smooth operation as the actuator is applied to the signal. . In contrast, in the present invention, in order to reduce the step difference and adjust the inclination of the actuator support, forming a sacrificial layer and then first etching the sacrificial layer using a first mask, and having a second size smaller than the first mask. The support portion of the actuator is introduced by introducing a process of secondly etching the inside of the first etched sacrificial layer using a mask and a process of finally wet etching the sacrificial layer using a mask having a size larger than that of the first mask. Since the slope of the actuator support can be smoothly formed by reducing the step difference and the inclination can be easily adjusted, the crack of the deformed layer generated in the actuator support can be reduced.

Referring to FIG. 6B, the support layer 125 is formed on the exposed etch stop layer 115 and on the sacrificial layer 120. The support layer 125 is formed to have a thickness of about 0.1 to 1.0 μm using a low pressure chemical vapor deposition (LPCVD) method of a rigid material such as nitride or metal. Subsequently, the lower electrode 130 is stacked on the support layer 125. The lower electrode 130 is formed of a metal having electrical conductivity such as platinum, tantalum, or platinum-tantalum (Pt-Ta) to have a thickness of about 0.01 to 1.0 탆 using a sputtering method. At the same time, the lower electrode 130 is separated for each pixel in order to apply an independent image signal (Iso-Cutting process).

A deformation layer 135 made of a piezoelectric material such as PZT or PLZT is stacked on the lower electrode 130. The strained layer 135 is formed to have a thickness of about 0.1 to 1.0 µm, preferably about 0.4 µm, using a sol-gel method, a chemical vapor deposition method, a sputtering method, or the like. In addition, the piezoelectric material constituting the primary-etched strain layer 135 is subjected to heat treatment by rapid thermal annealing (RTA) to phase change, and then polarized. In this case, since the portion of the deformable layer 135 constituting the support of the actuator 200 is laminated on the sacrificial layer 120 having the step difference reduced and the inclination adjusted, the crack in the deformed layer at the support of the actuator as in the prior art. This occurrence can be minimized. The strained layer 135 is deformed by an electric field generated between the upper electrode 140 and the lower electrode 130.

The upper electrode 140 is formed on the deformation layer 135. The upper electrode 140 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. The second signal is applied to the upper electrode 140 through a common electrode line (not shown) from the outside. Accordingly, when the first signal is applied to the lower electrode 130 and the second signal is applied to the upper electrode 140, an electric field is generated between the upper electrode 140 and the lower electrode 130. This electric field causes the strained layer 135 to deform. Since the upper electrode 140 made of aluminum, silver, platinum, or the like has excellent electrical conductivity and reflectivity, the upper electrode 140 performs not only a function of a bias electrode but also a mirror reflecting light incident from a light source.

Subsequently, the upper electrode 140, the strain layer 135, and the lower electrode 130 are sequentially patterned from a top of the upper electrode 140 into a predetermined pixel shape. At this time, a stripe 155 is formed at the center of the upper electrode 140 to uniformly operate the upper electrode 140 to prevent diffuse reflection of light incident from the light source.

Referring to FIG. 6C, the strained layer 135, the lower electrode 130, the support layer 125, 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. ) 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. 6D, the sacrificial layer 120 is etched using hydrogen fluoride (HF) vapor to form an air gap 160, and then rinsed and dry to perform an AMA device. Complete

After completing the M × N thin film type AMA devices as described above, the active matrix 100 may be sputtered or evaporated on a metal such as chromium (Cr), nickel (Ni), or gold (Au). At the bottom of the to form an ohmic contact (not shown). The active matrix 100 is then cut to a predetermined thickness for subsequent processing. Subsequently, the pad of the AMA panel (not shown) is exposed, and the active matrix 100 is cut out completely 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.

In the above-described thin film type optical path control device according to the present invention, the first signal transmitted from the outside through the pad of the TCP and the pad of the AMA panel is a transistor, a drain pad 105 and a via contact (embedded in the active matrix 100). It is applied to the lower electrode 130 which is a signal electrode through the 150. At the same time, a second signal is applied to the upper electrode 140 from the outside through a pad of TCP, a pad of an AMA panel, and a 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 strained layer 135 is contracted in a direction perpendicular to the electric field, and thus the actuator 200 is bent at a predetermined angle. Since the upper electrode 140, which also functions as a mirror that reflects light, 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 and adjust the inclination of the actuator support, forming a sacrificial layer and then first etching the sacrificial layer using a first mask, the second Second etching the inside of the first etched sacrificial layer using a second mask having a size smaller than one mask, and finally wet etching the sacrificial layer using a mask having a size larger than the first mask By incorporating the step, the inclination can be easily adjusted by reducing the step of the support part of the actuator, so that the inclination of the actuator support part can be smoothly formed. Therefore, the crack of the deformation | transformation layer which generate | occur | produces in an actuator support part can be reduced.

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 (5)

Providing an active matrix having M × N transistors embedded therein and having a drain pad formed on one side thereof; Iii) forming a sacrificial layer on top of the active matrix and the drain pad, ii) applying a first photoresist on top of the sacrificial layer, and then using the first photoresist as a first mask First etching a portion of the layer in which the drain pad is formed, and iii) applying a second photoresist on the sacrificial layer, and then using the second photoresist as a second mask. Forming a support of the actuator, the second etching of the inside of the primary etched portion to expose the active matrix; And Forming a support layer on the exposed active matrix and the sacrificial layer, forming a lower electrode on the support layer, forming a strain layer on the lower electrode, and an upper portion on the strain layer Forming an actuator comprising forming an electrode and forming a via contact connecting the lower electrode and the drain pad. The method of claim 1, wherein the first etching of the sacrificial layer is performed by patterning the first photoresist to form openings in the first photoresist, and then using the first photoresist as a first mask. The manufacturing method of the thin film type optical path control apparatus characterized by the above-mentioned. The second photoresist of claim 1, wherein the second etching of the sacrificial layer comprises patterning the second photoresist to form an opening having a smaller size than the first mask in the second photoresist. Method of manufacturing a thin film type optical path control device, characterized in that carried out using a second mask. The method of claim 1, wherein the forming of the support part of the actuator further comprises: wet etching the first and second etched sacrificial layers to adjust the inclination of the etched portion of the sacrificial layer. Method for manufacturing a thin film type optical path control device. 5. The method of claim 4, wherein adjusting the inclination of the etched portion of the sacrificial layer comprises applying a third photoresist on the first and second etched sacrificial layers and then patterning the third photoresist. And forming an opening larger in size than the first mask, and wet etching the sacrificial layer using the third photoresist as a third mask.

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