KR100248488B1 - Method of manufacturing tma - Google Patents

Abstract

Disclosed is a method of manufacturing a thin film type optical path control device. The method includes providing an active matrix having a drain pad formed on one side; Forming a sacrificial layer on top of the active matrix; Forming a support layer on the sacrificial layer, forming a lower electrode on the support layer, forming a strain layer on the lower electrode, and forming an upper electrode on the strain layer, And forming a via contact from an upper portion of the strained layer to the drain pad in a vertical direction. Applying a first photoresist to completely cover exposed surfaces of the upper electrode, the strain layer, and the lower electrode, and stabilizing the first photoresist; Applying a second photoresist on top of the stabilized first photoresist and stabilizing the second photoresist; And etching the support layer using the stabilized first and second photoresists as a mask and subsequently etching the sacrificial layer to form an air gap. Therefore, by increasing and stabilizing the thickness of the photoresist used as a mask in the etching process of the support layer and the sacrificial layer, it is possible to prevent the photoresist from being lifted off or damaged during the etching process by hydrogen fluoride vapor. have.

Description

Manufacturing method of thin film type optical path control device

The present invention relates to a method for manufacturing a thin film type optical path control apparatus using an Actuated Mirror Array (AMA), and more particularly, when an etching process using hydrogen fluoride (HF) vapor is performed to form an air gap. The present invention relates to a method for manufacturing a thin film type optical path control apparatus capable of preventing lift-off of photoresist and attack of a strained layer.

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. Typically, such devices are classified into a direct-view image display device and a projection-type image display device according to a method of displaying optical energy on a screen.

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. The actuator may 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 manufacturing, and has a disadvantage in that the response of the strained layer 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 Korean Patent Application No. 96-42197 (name of the invention: a method of manufacturing a thin film type optical path control device that can control the stress of the membrane) filed by the applicant of the Korean Patent Office on September 24, 1996. It is.

1 is a cross-sectional view of a thin film type optical path adjusting device described in the above prior application.

Referring to FIG. 1, the thin film type optical path adjusting device includes an active matrix 1 and an actuator 60. The active matrix 1 having M × N (M, N is an integer) MOS (Metal Oxide Semiconductor) transistors and a drain pad 5 formed on one surface thereof includes the active matrix 1 and the drain pad. The protective layer 10 stacked on the upper portion of the (5) and the etch stop layer 15 stacked on the protective layer 10 is included.

The actuator 60 may be stacked such that one side of the actuator 60 is in contact with a portion of the etch stop layer 15 in which the drain pad 5 is formed, and the other side thereof is parallel to the etch stop layer 15 via the air gap 25. Membrane 30, lower electrode 35 stacked on top of membrane 30, strained layer 40 stacked on top of lower electrode 35, and stacked on top of strained layer 40. Vias formed vertically from the one side of the upper electrode 45 and the strained layer 40 to the drain pad 5 through the lower electrode 35, the membrane 30, the etch stop layer 15, and the protective layer 10. The lower electrode 35 and the drain pad 5 are formed in the hole 50 to have a via contact 55 electrically connected to each other.

A stripe 46 is formed on a portion of the upper electrode 45. The stripe 46 operates the upper electrode 45 uniformly to prevent diffuse reflection of light incident from the light source.

Hereinafter, the manufacturing method of the thin film type optical path control apparatus will be described with reference to FIGS.

Referring to FIG. 2A, a silicate glass (Phosphor-) is formed on an active matrix 1 having M × N (M and N are integers) transistors (not shown) and a drain pad 5 formed on one side thereof. A protective layer 10 made of Silicate Glass (PSG) is formed. The protective layer 10 is formed to have a thickness of about 1.0 μm by using a chemical vapor deposition (CVD) method. The protective layer 10 protects the active matrix 1 from subsequent processes.

An etch stop layer 15 made of nitride is formed on the protective layer 10. The etch stop layer 15 is formed to have a thickness of about 0.01 to 1.0 μm 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 during the subsequent etching process. The sacrificial layer 20 is formed on the etch stop layer 15. The sacrificial layer 20 is formed of phosphorus silicate glass having a high concentration of phosphorus (P) to have a thickness of about 1.0 to 3.0 μm using an Atmospheric Pressure Vapor Deposition (APCVD) method. In this case, since the sacrificial layer 20 covers the upper portion of the active matrix 1 in which the transistor is embedded, the surface flatness is very poor. Therefore, the surface of the sacrificial layer 20 is planarized by using a spin-on glass (SOG) method or a chemical mechanical polishing (CMP) method. Subsequently, a portion of the sacrificial layer 20 in which the drain pad 5 is formed is etched to expose a portion of the etch stop layer 15 to form a position where the support portion of the actuator is to be formed.

Referring to FIG. 2B, the membrane 30 is formed on the exposed etch stop layer 15 and the sacrificial layer 20 to a thickness of about 0.1 to 1.0 μm. Membrane 30 is formed using low pressure chemical vapor deposition (LPCVD). At this time, by forming the membrane 30 while varying the ratio of the reaction gas in the reaction vessel of low pressure, the stress in the membrane 30 is controlled.

The lower electrode 35 made of a metal such as platinum (Pt) or platinum-tantalum (Pt-Ta) is formed on the membrane 30. The lower electrode 35 is formed to have a thickness of about 0.01 to 1.0 µm using a sputtering method. Subsequently, Iso-Cutting is performed to separate the lower electrode 35 for each pixel.

The deformation layer 40 formed of PZT or PLZT is formed on the lower electrode 35. The strained layer 40 is formed to have a thickness of about 0. 1 to 1.0 μm, preferably about 0.4 μm using a sol-gel method, and then rapid thermal annealing: RTA) phase change. The strained layer 40 is deformed by an electric field generated between the upper electrode 45 and the lower electrode 35.

The upper electrode 45 is formed on the strained layer 40. The upper electrode 45 is formed of a metal having excellent electrical conductivity and reflectivity, such as aluminum or platinum, to have a thickness of about 0.01 to 1.0 탆 using a sputtering method. The second signal (bias signal) is applied to the upper electrode 45 from the outside through a common electrode line (not shown). In addition, the upper electrode 45 also functions as a mirror that reflects light incident from the light source.

Referring to FIG. 2C, the upper electrode 45 is patterned into a predetermined pixel shape. In this case, the stripe 46 is patterned so that the stripe 46 is formed on one side of the upper electrode 45. Subsequently, the strained layer 40 and the lower electrode 35 are sequentially patterned into a predetermined pixel shape, and then the strained layer 40 is formed from an upper portion of one side of the strained layer 40 to an upper portion of the drain pad 5. The via hole 50 is formed by sequentially etching the lower electrode 35, the membrane 30, the etch stop layer 15, and the protective layer 10. Subsequently, a metal such as tungsten, platinum or titanium is deposited by a lift-off method to form a via contact 55 that electrically connects the drain pad 5 and the lower electrode 35. Thus, the via contact 55 is formed vertically from the lower electrode 35 to the top of the drain pad 5 in the via hole 50. Therefore, the first signal (image signal) applied from the outside is applied to the lower electrode 10 through the transistor, the drain pad 5 and the via contact 55 built in the active matrix 1.

Referring to FIG. 2D, the photoresist 57 is coated on the entire surface of the resultant product in which the via contact 55 is formed and patterned to expose the membrane 30. Subsequently, the membrane 30 is anisotropically etched using the photoresist 57 as an etching mask, thereby patterning a predetermined pixel shape. At this time, the photoresist 57 is lost to some extent to become thinner than the original thickness (see dotted line).

Referring to FIG. 2E, an air gap 59 is formed by isotropically etching the sacrificial layer 20 by 49% hydrogen fluoride (HF) vapor using the photoresist 57 as an etching mask. Subsequently, the AMA device is completed by removing the photoresist 57 and performing a washing and drying process.

In the above-described thin film type optical path adjusting device, the first signal is applied to the lower electrode 35 serving as the signal electrode through the drain pad 5 and the via contact 55 from the MOS transistor embedded in the active matrix 1. In addition, a second signal is applied to the upper electrode 45, which is a common electrode, to generate an electric field between the upper electrode 45 and the lower electrode 35. Due to this electric field, the strained layer 40 stacked between the upper electrode 45 and the lower electrode 35 causes deformation. The strained layer 40 contracts in a direction perpendicular to the electric field, and the actuator 60 including the strained layer 40 is bent in a direction opposite to the direction in which the membrane 30 is formed. Therefore, the upper electrode 49 above the actuator 60 is also inclined in the same direction. Light incident from the light source is reflected by the upper electrode 49 at a predetermined angle, and then is projected onto the screen to form an image.

However, the above-described thin film type optical path control apparatus performs etching using hydrogen fluoride vapor to remove the sacrificial layer, wherein the photoresist mask used is a photoresist used when etching the membrane in the pixel shape in the previous step. That is, the etching of the membrane and the etching of the sacrificial layer proceed continuously using one photoresist mask. Therefore, since the photoresist is also etched to some extent when the membrane is etched, the photoresist thickness when the sacrificial layer is etched becomes thinner than the original photoresist thickness so that the photoresist is lifted during the etching process using hydrogen fluoride vapor. There is a problem of turning off.

In addition, the 49% hydrogen fluoride solution tends to penetrate the photoresist, and the penetration tendency of the hydrogen fluoride solution is further enhanced when there are pinholes and defects in the photoresist. Accordingly, during the etching process using hydrogen fluoride vapor, the hydrogen fluoride vapor penetrates the photoresist and damages the strained layer, thereby lowering the yield of the AMA device.

Accordingly, it is an object of the present invention to provide a method of manufacturing a thin film type optical path control apparatus capable of preventing lift-off of photoresist and damage of a strained layer when performing an etching process by hydrogen fluoride vapor to form an air gap. have.

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

2A to 2E are cross-sectional views illustrating a method of manufacturing the apparatus shown in FIG. 1.

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

4 is a cross-sectional view of the apparatus shown in FIG. 3 taken along the line A-A '.

5A to 5G are cross-sectional views illustrating a method of manufacturing the apparatus shown in FIG. 4.

<Description of the code | symbol about the principal part of drawing>

131: active matrix 133: actuator

135: drain pad 137: protective layer

139: etch stop layer 141: sacrificial layer

143: support layer 145: lower electrode

147: strained layer 149: upper electrode

151 stripe 153 empty hole

155: beer contact 157: air gap

In order to achieve the above object of the present invention, the present invention comprises the steps of providing an active matrix having a drain pad formed on one side; Forming a sacrificial layer on top of the active matrix; i) forming a support layer on top of the sacrificial layer, ii) forming a bottom electrode on top of the support layer, iii) forming a strained layer on top of the bottom electrode, iv) a top of the strained layer Forming an actuator in the upper electrode, and v) forming a via contact vertically from an upper portion of one side of the strained layer to the drain pad; Applying a first photoresist to completely cover exposed surfaces of the upper electrode, the strain layer, and the lower electrode, and stabilizing the first photoresist; Applying a second photoresist on top of the stabilized first photoresist and stabilizing the second photoresist; And etching the support layer using the stabilized first and second photoresists as a mask and subsequently etching the sacrificial layer to form an air gap.

In the above-described thin film type optical path control apparatus of the present invention, the first signal (image signal) transmitted from the outside is applied to the lower electrode through the MOS transistor, the drain pad, and the via contact embedded in the active matrix. At the same time, a second signal (bias 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. 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 is bent in a direction opposite to the direction in which the support layer 143 is formed. Therefore, the upper electrode which also functions as a mirror on the actuator is inclined in the same direction. Accordingly, the light incident from the light source is reflected by the inclined upper electrode at a predetermined angle, and then passes through the slit to be projected onto the screen to form an image.

According to the manufacturing method of the thin film type optical path control apparatus according to the present invention, the photoresist is applied once so as to completely cover the exposed surfaces of the upper electrode, the deformable layer, and the lower electrode, which is then subjected to electron beam (E-beam) treatment or ultraviolet treatment ( After UV-curing, the photoresist is again applied twice and subjected to electron beam or ultraviolet treatment. Therefore, even if the photoresist is lost to some extent during the etching of the support layer, the thickness of the photoresist remaining in the subsequent etching process by the hydrogen fluoride vapor becomes thicker than the thickness of the photoresist applied once. Therefore, it is possible to prevent the photoresist from being lifted off during the etching process of the sacrificial layer using hydrogen fluoride vapor.

In addition, the photoresist is stabilized by electron beam treatment or ultraviolet treatment after each coating step to remove pinholes or defects in the photoresist. Therefore, since the penetration path of hydrogen fluoride vapor in the photoresist can be reduced, it is possible to prevent damage to the strained layer due to hydrogen fluoride vapor.

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

3 is a plan view of a thin film type optical path control device according to the present invention, Figure 4 is a cross-sectional view taken along the line A-A 'of the device shown in FIG.

3 and 4, the thin film type optical path adjusting apparatus according to the present invention includes an active matrix 131 and an actuator 133 formed on the active matrix 131. The active matrix 131 in which M x N (M, N is an integer) MOS transistors (not shown) and a drain pad 135 is formed on one surface thereof includes the active matrix 131 and the drain pad. A protective layer 137 stacked on the upper portion of the 135, and an etch stop layer 139 stacked on the protective layer 137.

The actuator 133 is stacked such that one side of the actuator 133 contacts the portion of the etch stop layer 139 in which the drain pad 135 is formed and the other side thereof is parallel to the etch stop layer 139 through the air gap 157. A support layer 143 having a cross-sectional shape, a lower electrode 145 stacked on top of the support layer 143, a strained layer 147 stacked on top of the lower electrode 145, and stacked on top of the strained layer 147. An upper electrode 149 and a vertically formed from one side of the strain layer 147 to the drain pad 135 through the lower electrode 145, the support layer 143, the etch stop layer 139, and the protective layer 137. The via hole 153 includes a via contact 155 formed to electrically connect the lower electrode 145 and the drain pad 135 to each other.

In addition, referring to FIG. 3, the plane of the support layer 143 is formed in a shape in which one side thereof has a rectangular concave portion at the center thereof, and the concave portion becomes stepped toward both edges. The other side of the support layer 143 has a rectangular protrusion that narrows stepwise toward the center portion corresponding to the concave portion. Therefore, the protrusion of the support layer of the actuator adjacent to the concave portion of the support layer 143 is fitted, and the rectangular protrusion is fitted to the concave portion of the support layer of the adjacent actuator. The support layer 143 serves as a membrane supporting the actuator of the thin film type optical path adjusting device described in the previous application. A stripe 151 is formed on a portion of the upper electrode 149. The stripe 151 operates the upper electrode 149 uniformly to prevent diffuse reflection of light incident from the light source.

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

5A to 5G are cross-sectional views illustrating a method of manufacturing the apparatus shown in FIG. 4. 5A to 5G, the same reference numerals are used for the same members as in FIG.

Referring to FIG. 5A, a protective layer 137 is formed on an active matrix 131 having M × N (M and N are integers) MOS transistors (not shown) and a drain pad 135 formed on one side thereof. To form. The active matrix 131 is made of a semiconductor such as silicon or an insulating material such as glass or alumina (Al ₂ O ₃ ). The protective layer 137 is formed of a silicate glass (PSG) to have a thickness of about 1.0 μm using a chemical vapor deposition (CVD) method. The protective layer 137 prevents the transistor embedded in the active matrix 131 from being damaged from a subsequent process.

Subsequently, an etch stop layer 139 is formed on the passivation layer 137. The etch stop layer 139 is formed using a low pressure chemical vapor deposition (LPCVD) method so as to have a thickness of about 0.1 to 1.0 μm. The etch stop layer 139 prevents the protective layer 137 and the active matrix 131 containing the transistor from being etched during the subsequent etching process.

Subsequently, a sacrificial layer 141 is formed on the etch stop layer 139. The sacrificial layer 141 is formed of phosphorus silicate glass (PSG) having a high concentration of phosphorus (PG) to have a thickness of about 1.0 to 3.0 μm using the atmospheric pressure chemical vapor deposition (APCVD) method. In this case, since the sacrificial layer 141 covers the upper portion of the active matrix 131 in which the transistor is embedded, the flatness of the surface thereof is very poor. Accordingly, the surface of the sacrificial layer 141 is planarized by using spin on glass (SOG) or chemical mechanical polishing (CMP). Subsequently, a portion of the sacrificial layer 141 in which the drain pad 135 is formed is etched to expose a portion of the etch stop layer 139 to form a position where the support portion of the actuator is to be formed.

Referring to FIG. 5B, the support layer 143 is formed on the exposed etch stop layer 139 and the sacrificial layer 141 to a thickness of about 0.1 to 1.0 μm. The support layer 143 is formed using a low pressure chemical vapor deposition (LPCVD) method. At this time, the stress in the support layer 143 is adjusted by forming the support layer 143 while changing the ratio of the reaction gas in the low pressure reaction vessel.

Referring to FIG. 5C, a lower electrode 145 made of metal such as platinum (Pt) or platinum-tantalum (Pt-Ta) is formed on the support layer 143. The lower electrode 145 is formed to have a thickness of about 0.01 to 1.0 μm using a sputtering method or a chemical vapor deposition method. A first signal (image signal) is externally applied to the lower electrode 145, which is a signal electrode, through the transistor embedded in the active matrix 131 and the drain pad 135. Subsequently, Iso-Cutting is performed to separate the lower electrode 145 for each pixel.

On the lower electrode 145, a strain layer 147 made of a piezoelectric material such as PZT or PLZT is formed. The strained layer 147 may have a thickness of about 0.1 to 1.0 μm, preferably about 0.4 μm using a sol-gel method, a sputtering method, or a chemical vapor deposition (CVD) method. After the formation, the piezoelectric material constituting the strained layer 147 is phase shifted and polarized by a rapid heat treatment (RTA) method. The deformation layer 147 is deformed by an electric field generated between the upper electrode 149 and the lower electrode 145.

Subsequently, the upper electrode 149 is formed on the strained layer 147. The upper electrode 149 is formed of a metal having excellent electrical conductivity and reflectivity, such as aluminum (Al), silver (Ag), or platinum (Pt), to have a thickness of about 0.01 to 1.0 탆 using a sputtering method. . The second electrode (bias signal) is applied to the upper electrode 149 through a common electrode line (not shown) from the outside, and at the same time, the upper electrode 149 also functions as a mirror that reflects light incident from the light source. .

Subsequently, the upper electrode 149, the strain layer 147, and the lower electrode 145 are sequentially patterned into a predetermined pixel shape. That is, after forming a photoresist layer (not shown) resistant to the material to be etched on the upper electrode 149, the upper electrode 149 is patterned. At this time, the upper electrode 149 is patterned such that a stripe 151 is formed to uniformly operate the upper electrode 149 on one side of the upper electrode 149 to prevent diffuse reflection of light incident from the light source. Subsequently, a photoresist protective layer (not shown) is again formed on the patterned upper electrode 149 and the strained layer 147, and then the strained layer 147 is patterned into a predetermined pixel shape. In this manner, the lower electrode 145 is also patterned into a predetermined pixel shape.

Referring to FIG. 5D, the strain layer 147 and the lower electrode from the portion in which the drain pad 135 is formed below the strain layer 147 to the upper portion of the drain pad 135 using a photolithography process. The via hole 153 is formed by sequentially etching the 145, the support layer 143, the etch stop layer 139, and the protective layer 137. Subsequently, a metal such as tungsten (W), platinum (Pt), or titanium (Ti) is deposited to form a via contact 155 that electrically connects the drain pad 135 and the lower electrode 145. Thus, the via contact 155 is formed vertically from the lower electrode 145 to the top of the drain pad 135 in the via hole 153. Therefore, the first signal applied from the outside is applied to the lower electrode 145 through the transistor, the drain pad 135 and the via contact 155 embedded in the active matrix 131.

Referring to FIG. 5E, the first photoresist layer 160a is coated on the entire surface of the resultant in which the via contact 155 is formed, and then the first photoresist layer 160a is stabilized by electron beam treatment or ultraviolet ray treatment. Let's do it.

Referring to FIG. 5F, the second photoresist layer 160b is coated on the stabilized first photoresist layer 160, and then the second photoresist layer 160b is subjected to electron beam or ultraviolet light treatment. Stabilize. Subsequently, the stabilized first and second photoresist layers 160a and 160b are patterned to completely cover the upper side of the upper electrode 149 and the side surfaces of the strained layer 147 and the lower electrode 145. Next, using the stabilized first and second photoresist layers 160a and 160b as an etching mask, the support layer 143 is patterned into a predetermined pixel shape by an anisotropic etching process. In the present invention, since the photoresist is applied twice to increase the thickness as described above, even if the photoresist is lost to some extent during the etching of the support layer 143, the photo remains during the subsequent etching process by hydrogen fluoride vapor. The thickness of the resist becomes thicker than the thickness of the photoresist applied once.

Referring to FIG. 5G, the air gap 157 by isotropically etching the sacrificial layer 141 by 49% hydrogen fluoride vapor using the stabilized first and second photoresist layers 160a and 160b as an etching mask. ). Subsequently, the stabilized first and second photoresist layers 160a and 160b are removed, washed and dried to form an actuator 133. Subsequently, rinsing and drying are 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) may be sputtered or evaporated into the active matrix 131. It is deposited at the bottom to form an ohmic contact (not shown). Next, a conventional photolithography process is used to prepare a Tape Carrier Package (TCP) (not shown) bonding for applying a second signal to the upper electrode 149 and a first signal to the lower electrode 145. By cutting the active matrix 131 to a predetermined thickness. Subsequently, a photoresist layer (not shown) is formed over 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, in which no pad is formed, is patterned to expose the pad of the AMA panel. Next, the photoresist layer is etched and the active matrix 131 is completely cut into a predetermined shape, and then the pad of the AMA panel and the pad of TCP are unidirectional conductive resin (ACF) (not shown). To complete the manufacture of the thin-film AMA module.

In the above-described thin film type optical path control device of the present invention, the first signal transmitted from the outside through the pad of the TCP and the pad of the AMA panel is MOS transistor, drain pad 135 and via contact (built in the active matrix 131). It is applied to the lower electrode 145 through 155. At the same time, a second signal is applied to the upper electrode 149 through the common electrode line from the outside to generate an electric field between the upper electrode 149 and the lower electrode 145. Due to this electric field, the deformation layer 147 formed between the upper electrode 149 and the lower electrode 145 causes deformation. The strained layer 147 contracts in a direction perpendicular to the electric field, and the actuator 133 including the strained layer 147 is bent in a direction opposite to the direction in which the support layer 143 is formed. Therefore, the upper electrode 149 which also functions as a mirror on the actuator 133 is inclined in the same direction. Accordingly, the light incident from the light source is reflected by the inclined upper electrode 49 at a predetermined angle, and then passes through the slit to be projected onto the screen to form an image.

In addition, although not shown, the present invention may be applied to a thin film type optical path adjusting apparatus in which an upper electrode is used only as a bias electrode to which a second signal is applied, and a mirror for reflecting light incident from a light source is formed on the upper electrode. Of course it can. In this case, the mirror is generally formed in a '-' shape horizontally with the upper electrode via the air gap having a support portion in contact with the upper side of the upper electrode.

As described above, according to the manufacturing method of the thin film type optical path control apparatus according to the present invention, the photoresist is applied once so as to completely cover the exposed surfaces of the upper electrode, the deforming layer, and the lower electrode, and then subjected to electron beam treatment or ultraviolet treatment. Then, the photoresist is applied twice and subjected to electron beam or ultraviolet treatment. Thus, even if the photoresist is lost to some extent during the etching of the support layer, the thickness of the photoresist remaining during the subsequent etching process with hydrogen fluoride vapor becomes thicker than the thickness of the photoresist applied once. Therefore, it is possible to prevent the photoresist from being lifted off during the etching process of the sacrificial layer using hydrogen fluoride vapor.

In addition, the photoresist is stabilized by electron beam treatment or ultraviolet treatment after each coating step to remove pinholes or defects in the photoresist. Therefore, since the penetration path of hydrogen fluoride vapor in the photoresist can be reduced, it is possible to prevent damage to the strained layer due to hydrogen fluoride vapor.

Although described above with reference to a preferred embodiment of the present invention, those skilled in the art will be variously modified and changed within the scope of the invention without departing from the spirit and scope of the invention described in the claims below I can understand that you can.

Claims (3)

Providing an active matrix having a drain pad formed on one side thereof; Forming a sacrificial layer on top of the active matrix; i) forming a support layer on top of the sacrificial layer, ii) forming a bottom electrode on top of the support layer, iii) forming a strained layer on top of the bottom electrode, iv) a top of the strained layer Forming an actuator in the upper electrode, and v) forming a via contact vertically from an upper portion of one side of the strained layer to the drain pad; Applying a first photoresist to completely cover exposed surfaces of the upper electrode, the strain layer, and the lower electrode, and stabilizing the first photoresist; Applying a second photoresist on top of the stabilized first photoresist and stabilizing the second photoresist; And etching the support layer using the stabilized first and second photoresists as masks and subsequently etching the sacrificial layer to form an air gap. The method of claim 1, wherein the stabilizing of the first photoresist is performed by electron beam treatment or ultraviolet ray treatment. The method of claim 1, wherein the stabilizing of the second photoresist is performed by electron beam treatment or ultraviolet ray treatment.

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