KR100271000B1 - Thin flim actuatred mirror array and method for manufacturing the same - Google Patents

Abstract

PURPOSE: A thin film actuated mirror array is provided to prevent a short circuit between a top electrode and a bottom electrode, and to prevent an active layer from being cracked. CONSTITUTION: An active matrix(100) includes M by N MOS transistors and a drain pad(105) extended from a drain of the transistor. A support layer(125) has one side connected to a top of the active matrix(100). The other side of the support layer(125) is formed in parallel, with an air gap(160) interposed therebetween. A bottom electrode(130) is formed on the support layer(125) and is partitioned by an Iso-Cut part according to each pixel. An active layer(135) is formed on the bottom electrode(130), and a separation layer(138) is formed at a step portion between the Iso-Cut part and the active layer(135). An etch protection layer(152) is formed on a sidewall of the separation layer(138), and a top electrode(140) is formed on the active layer(135).

Description

Thin film type optical path control device and its manufacturing method

The present invention relates to a thin film type optical path control apparatus using AMA (Actuated Mirror Array) and a method of manufacturing the same, and more particularly, to form an isolation layer for reinforcing the IsoCut part of the lower electrode and to fluorinate the IsoCut part. In forming an etch protective layer to prevent hydrogen (HF) vapor from penetrating, it is possible to prevent electrical short between the upper electrode and the lower electrode and to prevent cracking in the strained layer. It relates to a thin film type optical path control device and a method of manufacturing the same.

Spatial light modulators, which are devices for projecting optical energy onto a screen, can 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. Examples of the projection image display apparatus 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 (10% or more) can be obtained compared to LCD or DMD. In addition, the contrast of the image projected on the screen is improved to obtain a brighter and clearer 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 the incident light 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 control device is made by thinly cutting a multilayer ceramic to mount a ceramic wafer having a metal electrode therein into an active matrix in which a transistor is built, and then processing by using a sawing method and installing a mirror on the top. . 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.

Figure 1b shows a cross-sectional view of the thin film type optical path control device described in the preceding application.

Referring to FIG. 1B, the thin film type optical path adjusting device includes an active matrix 1 and an actuator 60. An active matrix 1 having an M × N (M, N is an integer) MOS transistor embedded therein and having a drain pad 5 extending from a drain region of the transistor includes the active matrix 1 and a 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 has one side in contact with a portion in which the drain pad 5 is formed below the etch stop layer 15, and the other side has a membrane 30 and a membrane formed horizontally through the air gap 25. The lower electrode 35 stacked on the upper portion 30, the strained layer 40 stacked on the lower electrode 35, the upper electrode 45 stacked on the strained layer 40, and the strained layer ( The lower electrode 35 in the via hole 50 vertically formed from one side of the 40 to the drain pad 5 through the lower electrode 35, the membrane 30, the etch stop layer 15, and the protective layer 10. And the drain pad 5 include a via contact 55 formed to be electrically connected to each other.

A stripe 46 is formed on a portion of the upper electrode 45. The stripe 46 uniformly operates the upper electrode 45 so that light incident from the light source is diffusely reflected at the boundary between the portion of the upper electrode 45 that is deformed and the portion that is not deformed according to the deformation of the strained layer 40. To prevent them.

Hereinafter, a manufacturing method of the thin film type optical path control device will be described with reference to FIGS. 1A to 1B.

Referring to FIG. 1A, an M × N (M, N is an integer) phosphorus is formed on an active matrix 1 in which a MOS transistor (not shown) is embedded and a drain pad 5 extending from the drain region of the transistor is formed. A protective layer 10 composed of silicate glass PSG is formed. The protective layer 10 is formed to have a thickness of about 1.0 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.

An etch stop layer 15 made of nitride is formed on the passivation layer 10. The etch stop layer 15 is formed to have a thickness of about 1000 to 2000 kPa using a low pressure chemical vapor deposition (LPCVD) method. The etch stop layer 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 phosphorous silicate glass (PSG) having a high concentration of phosphorus (PG) to have a thickness of about 1.0 to 3.0 μm by using an atmospheric pressure chemical 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. Accordingly, the surface of the sacrificial layer 20 is planarized by using spin on glass (SOG) or chemical mechanical polishing (CMP). 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, thereby making a position where the support of the actuator 60 is to be formed.

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㎛. The membrane 30 forms nitride using low pressure chemical vapor deposition (LPCVD). At this time, the membrane 30 is formed while varying the ratio of the reaction gas in the reaction vessel at a low pressure to control the stress in the membrane 30.

On the membrane 30, a lower electrode 35 made of metal such as platinum (Pt), tantalum (Ta), or platinum-tantalum is formed. The lower electrode 35 is formed to have a thickness of about 0.1 to 1.0 μm using a sputtering method. Subsequently, the lower electrode 35 is patterned to separate the lower electrode 35 for each pixel so that an independent first signal (image signal) is applied to each pixel (Iso­Cut etching process).

The deformation layer 40 made of a piezoelectric material such as PZT or PLZT is formed on the lower electrode 35. The strained layer 40 is formed to have a thickness of about 0.1 μm to about 1.0 μm, preferably about 0.4 μm using a sol-gel method, and then phase-shifted by a rapid heat treatment (RTA) method. The strained layer 40 is applied with a second signal (bias signal) to the upper electrode 45 and a first signal is applied to the lower electrode 35 so that the potential difference between the upper electrode 45 and the lower electrode 35 is reduced. Deformation is caused by the electric field generated.

The upper electrode 45 is formed on the strained layer 40. The upper electrode 45 is formed of a metal having electrical conductivity and reflectivity, such as aluminum or platinum, to have a thickness of about 0.1 to 1.0 μm using a sputtering method. The second signal is applied to the upper electrode 45 through a common electrode line (not shown) from the outside. In addition, the upper electrode 45 also functions as a mirror that reflects light incident from the light source.

Referring to FIG. 1B, the upper electrode 45, the deformation layer 40, and the lower electrode 35 are each patterned into a predetermined pixel shape. At this time, a portion of the upper electrode 45 is patterned to form a stripe 46. Subsequently, the strained layer 40, the lower electrode 35, the membrane 30, the etch stop layer 15, and the protective layer 10 are sequentially formed from one side of the strained layer 40 to the top of the drain pad 5. The via hole 50 is formed by etching. Subsequently, a via contact 55 is formed in the via hole 50 to sputter a metal such as tungsten, platinum or titanium to electrically connect the drain pad 5 to the lower electrode 35. Therefore, the via contact 55 is formed vertically from the lower electrode 35 to the drain pad 5 in the via hole 50. Therefore, the first signal applied from the outside is applied to the lower electrode 35 through the transistor, the drain pad 5, and the via contact 55 embedded in the active matrix 1.

Subsequently, the membrane 30 is patterned to have a predetermined pixel shape. After the air gap 25 is formed at the position of the sacrificial layer 20 by etching the sacrificial layer 20 by 49% hydrogen fluoride (HF) vapor, the cleaning and cleaning may be performed to remove the remaining etching solution. AMA element is completed by performing a drying process.

In the above-described thin film type optical path adjusting device, the first signal is applied to the lower electrode 35 through the MOS transistor, the drain pad 5, and the via contact 55 embedded in the active matrix 1. At the same time, a second signal is applied to the upper electrode 45 through the common electrode line to generate an electric field between the upper electrode 45 and the lower electrode 35. By the 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 upward at a predetermined angle. Therefore, the upper electrode 45 on the actuator 60 is also inclined in the same direction. Light incident from the light source is reflected by the upper electrode 45 at a predetermined angle, and then is projected onto the screen to form an image.

However, in the above-described thin film type optical path control apparatus, when the etching process for patterning the strained layer, the lower electrode, and the membrane into a pixel shape is performed, a problem occurs in that Iso­Cut portion of the lower electrode is damaged. This will be described in more detail with reference to the drawings.

2 is an enlarged plan view of an Iso­Cut part in the above-described thin film type optical path adjusting device. Referring to FIG. 2, in the above-described method for manufacturing a thin film type optical path control apparatus, an IsoCut part (eg, an IsoCut part) may be used to perform etching processes for patterning the deformable layer 40, the lower electrode 35, and the membrane 30 into a predetermined pixel shape. A) is exposed without being covered with a photoresist film. Therefore, during the above etching processes, the membrane 30 of the Iso­Cut portion A is over-etched and etched down to the lower etch stop layer. As a result, when the sacrificial layer is etched using hydrogen fluoride (HF) vapor, hydrogen fluoride vapor penetrates through the etched portion of the etch stop layer to damage the protective layer and the active matrix.

In addition, according to the manufacturing method of the thin film type optical path control apparatus described above, since the iso-cut addition film becomes a nitride layer, the metal layer such as platinum (Pt) or tantalum constituting the lower electrode 35 has different physical properties. do. In particular, since the strained layer made of a piezoelectric material such as PZT has a property of not being deposited well on top of the nitride layer, voids occur in the iso-cut portion. As described above, when a rapid heat treatment (RTA) process for phase shifting the piezoelectric material constituting the strained layer is performed in the state where voids are formed in the strained layer, the strained layer is inflated and cracks are generated in the strained layer. Done. If cracks occur in the strained layer, not only the piezoelectric properties of the strained layer are lowered, but also a problem arises in that the upper electrode deposited thereon is short-circuited or the photolithography process for patterning the upper electrode cannot be reliably performed.

Recently, in order to prevent the Iso ICut portion from being damaged, a method of depositing an etch protective layer made of a material such as amorphous silicon after patterning the pixel shape to the membrane, leaving an etch protective layer of the Iso­Cut portion, and etching the rest has been proposed. Since the etch protection layer is made of a material (PECVD-amorphous silicon) that is not etched during the subsequent etching process with hydrogen fluoride, hydrogen fluoride vapor can be prevented from penetrating through the Iso­Cut part. The etch protective layer is removed by a blanket etch method after performing an etching process by hydrogen fluoride vapor. However, according to the above method, since the thickness of the etch protective layer formed on the stepped surface of the upper electrode and the lower electrode is relatively thicker than the thickness at other portions, the upper electrode and the lower electrode after removing the etch protective layer by the blanket etching method. The etching protection layer remains on the stepped surface of the electrode. Thus, an electrical short is caused between the upper electrode and the lower electrode.

In addition, in order to prevent cracks from occurring in the strained layer made of a piezoelectric material such as PZT, after the lower electrode is deposited, the IsoCut process is omitted, and the strained layer and the upper electrode are sequentially deposited thereon, and then the upper electrode. In addition, a method of isocutting a method of separating the lower electrode by each pixel while etching the strained layer into the pixel shape and etching the lower electrode into the pixel shape is also proposed. Therefore, since the IsoCut portion of the lower electrode is not formed prior to depositing the strained layer made of piezoelectric material such as PZT, the strained layer is deposited only on the platinum layer or tantalum layer and the thin metal layer, not on the nitride layer, and subsequently on the upper side. Cracks do not occur during the heat treatment process for this. However, according to the above method, since the upper electrode must be separated for each pixel in order to IsoCut the lower electrode, connecting the upper electrode separated for each pixel by a lift-off process after performing the IsoCut process. To form a metal layer. Therefore, not only the area of the upper electrode is reduced, but also a problem arises in that the resistance of the adhesive surface is increased by the lift-off process.

Accordingly, it is an object of the present invention to form an isolation layer for reinforcing the IsoCut portion of the lower electrode and to form an etch protective layer for preventing hydrogen fluoride vapor from penetrating the IsoCut portion. It is to provide a thin film-type optical path control device and a method of manufacturing the same that can prevent an electrical short circuit and to prevent cracks in the deformation layer.

1A and 1B are cross-sectional views illustrating a method of manufacturing a thin film type optical path adjusting device described in the applicant's prior application.

FIG. 2 is an enlarged plan view illustrating an Iso-Cut part in the thin film type optical path adjusting device described in the above prior application. FIG.

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 line B-B '.

FIG. 5 is a cross-sectional view of the apparatus shown in FIG. 3 taken along line C-C '.

6A to 6G 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>

100: active matrix 105: drain pad

110: protective layer 115: etch stop layer

125: support layer 130: lower electrode

135: strained layer 138: separation layer

140: upper electrode 145: via hole

150: via contact 152: etch protective layer

160: air gap

In order to achieve the above object of the present invention, the present invention relates to an active matrix comprising an M × N (M, N is an integer) MOS transistor and including a drain pad extending from the drain of the transistor. Provided is a thin film type optical path control device including an actuator formed thereon. The actuator may include: i) a support layer on one side of which is in contact with an upper portion of the active matrix and the other side of which is horizontally formed through an air gap; ii) a lower electrode formed on an upper portion of the support layer and separated for each pixel by an IsoCut part. A strained layer formed on the lower electrode, iii) a separation layer formed on the step surface of the IsoCut portion and the strained layer, and iii) an upper electrode formed on the strained layer.

In addition, in order to achieve the above object of the present invention, the present invention provides a step of providing an active matrix including a drain pad is embedded with M × N (M, N is an integer) and extends from the drain of the transistor ; 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, iii) IsoCut for each pixel, iii) forming a separation layer on the stepped surface of the IsoCut portion and the strained layer, iii) forming an upper electrode on the strained layer, iii) the support layer on the resultant Forming an etch protective layer in the same pattern as, and iii) forming an actuator having the step of removing the sacrificial layer to form an air gap provides a method of manufacturing a thin film type optical path control apparatus.

In the above-described thin film type optical path control apparatus according to the present invention, the first signal transmitted from the outside is applied to the lower electrode through the transistor, the drain pad and the via contact embedded in the active matrix. At the same time, the second signal is applied to the upper electrode from the outside to generate an electric field according to the potential difference 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 orthogonal to the electric field, whereby the actuator is bent at a predetermined angle. The upper electrode, which also functions as a mirror that reflects light, is formed on the actuator and is inclined with the actuator. Accordingly, the upper electrode 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.

Therefore, according to the present invention, after depositing a strained layer and patterning the strained layer into a pixel shape by a photolithography process, an IsoCut portion is formed on a lower electrode and a separation layer for reinforcing the IsoCut portion is formed on top of the resultant. The separation layer is patterned by a photolithography process. The separation layer may be formed to prevent electrical short between the upper electrode and the lower electrode due to an amorphous silicon etch protective layer formed to prevent penetration of hydrogen fluoride (HF) vapor into the IsoCut part. It is formed in the form of a spacer on the stepped surface of the strained layer. In addition, according to the present invention, after depositing the lower electrode, the Iso­Cut process is omitted, and a strained layer is deposited on the upper part. Therefore, the strained layer made of a piezoelectric material such as PZT is deposited only on the metal layer (lower electrode) such as the platinum layer or tantalum layer, not the nitride layer, so that the piezoelectric material is subjected to the heat treatment process for the phase change of the subsequent strained layer. Cracks do not occur in the deformed layer formed. In addition, according to the present invention, since each pixel is connected to the upper electrode itself without a separate metal layer, structural stabilization of the AMA device can be obtained.

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 apparatus according to the present invention, and FIGS. 4 and 5 are cross-sectional views taken along line B-B 'and line C-C' of the apparatus shown in FIG.

3 to 5, the thin film type optical path adjusting apparatus according to the present invention includes an active matrix 100 and an actuator 200 formed on the active matrix 100.

The active matrix 100 in which an M × N (M, N is an integer) MOS transistor (not shown) is formed therein and a drain pad 105 extending from the drain of the transistor is formed. And a protective layer 110 stacked on the drain pad 105 and an etch stop layer 115 stacked on the protective layer 110.

The actuator 200 has a support layer 125 and a support layer 125 formed at one side thereof in contact with a portion of the etch stop layer 115 at which a drain pad 105 is formed and the other side of the actuator 200 formed horizontally through an air gap 160. ), 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 via hole 145 formed vertically to 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. And a via contact 150 formed to connect the drain pad 5 and the lower electrode 35 to each other. The support layer 125 functions as a membrane supporting the actuator of the thin film type optical path adjusting device described in the previous application.

4 and 5, a separation layer 138 is formed on an Iso_Cut portion that separates the lower electrode 130 for each pixel. The separation layer 138 has an etch protection layer 152 formed to prevent penetration of hydrogen fluoride (HF) vapor into the IsoCut portion in a subsequent process, so that the separation layer 138 remains after the blanket etching process. In order to prevent electrical shorts between the electrodes 130, the stepped surface of the deforming layer 135 is formed in a spacer shape.

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

6A to 6G are cross-sectional views illustrating a method of manufacturing the apparatus shown in FIG. 4. 6A to 6G, the same reference numerals are used for the same members as in FIG.

Referring to FIG. 6A, a protective layer is formed on an active matrix 100 in which M × N (M and N are integers) MOS transistors (not shown) are formed and drain pads 5 extending from the drains of the transistors are formed. Form 110. The active matrix 100 is made of a semiconductor such as silicon or an insulating material such as glass or alumina (Al ₂ O ₃ ). The protective layer 110 may be formed to have a thickness of about 0.1 μm to about 1.0 μm by using a chemical vapor deposition (CVD) method. The protective layer 110 prevents damage to the active matrix 100 in which the MOS transistor is embedded during a subsequent process.

An etch stop layer 115 is formed on the passivation layer 110. The etch stop layer 115 is formed to have a thickness of about 1000 to 2000 kPa using a low pressure chemical vapor deposition (LPCVD) method. The etch stop layer 115 prevents the protective layer 110 and the active matrix 100 having the MOS transistor embedded therein from being etched during the subsequent etching process.

The sacrificial layer 120 is formed on the etch stop layer 115. The sacrificial layer 120 is formed by depositing a phosphorus silicate glass (PSG) having a high concentration of phosphorus (PG) to a thickness of about 2.0 to 3.3 μm using 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 MOS transistor is embedded, the surface flatness is very poor. Therefore, the surface of the sacrificial layer 120 is planarized by polishing using a spin on glass (SOG) method or a chemical mechanical polishing (CMP) method. 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 at which the support portion of the actuator 200 is to be formed.

Referring to FIG. 6B, a 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.

The lower electrode 130 is formed on the support layer 125. The lower electrode 130 is formed to have a thickness of about 0.1 μm to about 1.0 μm by sputtering a metal having electrical conductivity such as platinum (Pt), tantalum (Ta), or platinum-tantalum (Pt-Ta). The first electrode (image signal) is applied to the lower electrode 130 through the transistor and the drain pad 105 embedded in the active matrix 100 from the outside.

The deformation layer 135 made of a piezoelectric material such as PZT or PLZT is formed 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 sputtering method, or a chemical vapor deposition method. In the present invention, the Iso 변형 Cut portion is not formed in the lower electrode 130 before the strain layer 135 formed of the piezoelectric material such as PZT is formed. Therefore, since the strained layer 135 made of the piezoelectric material is deposited only on the lower electrode 130 made of metal such as platinum or tantalum, not the support layer 125 made of nitride, the strained layer 135 made of the piezoelectric material ) Is deposited without voids so that cracks do not occur inside the strained layer 135 during the heat treatment process of the strained layer 135 for subsequent phase transition. Subsequently, the piezoelectric material constituting the strained layer 135 is subjected to heat treatment by a rapid heat treatment (RTA) method to cause phase shift. The strained layer 135 is applied with a second signal (bias signal) to the upper electrode 140 and a first signal is applied to the lower electrode 130 so that a potential difference between the upper electrode 140 and the lower electrode 130 is applied. Deformation is caused by the electric field generated.

Referring to FIG. 6C, after the deformation layer 135 is patterned into a predetermined pixel shape through a photolithography process, an independent first signal is applied to each pixel by separating the lower electrode 130 for each pixel. IsoCut the lower electrode 130 as possible.

Subsequently, as an isolation layer 138 for reinforcing the Iso­Cut portion on the resultant, for example, an oxide film is deposited and the separation layer 138 is patterned by a photolithography process. The separation layer 138 is electrically connected between the upper electrode 140 and the lower electrode 130 due to an amorphous silicon etch protective layer 152 formed to prevent penetration of hydrogen fluoride (HF) vapor into the IsoCut portion. In order to prevent occurrence of a short circuit, the deformed layer 135 may be formed in a spacer shape.

Referring to FIG. 6D, the upper electrode 140 is formed on an upper portion of the resultant layer in which the separation layer 138 is formed. The upper electrode 140 is formed to have a thickness of about 0.1 to 1.0 μm by sputtering a metal having electrical conductivity and reflectivity such as aluminum (Al), silver (Ag), or platinum (Pt). The second signal is applied to the upper electrode 140 from the outside. Since the upper electrode 140 has excellent electrical conductivity and reflectivity, the upper electrode 140 performs not only a function of a bias electrode generating an electric field but also a function of a mirror reflecting light incident from a light source.

Subsequently, the upper electrode 140 is patterned into a predetermined pixel shape so as to overlap the boundary surface of the separation layer 138 by using a photolithography process, and then the lower electrode 130 using a photolithography process. Is patterned to have a predetermined pixel shape.

Referring to FIG. 6E, via holes may be sequentially etched from one side of the strained layer 135 by etching the strained layer 135, the lower electrode 130, the support layer 125, the etch stop layer 115, and the protective layer 110. 145 is formed. Thus, the via hole 145 is formed from one side of the strained layer 135 to the drain pad 105. Next, a via contact 150 is formed by sputtering a metal having electrical conductivity such as tungsten (W), aluminum (Al), or titanium (Ti) in the via hole 145. 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 embedded in the active matrix 100, the drain pad 105, and the via contact 150. The support layer 125 is patterned into a predetermined pixel shape including an Iso ICut portion by using a photolithography process.

Referring to FIG. 6F, after etching the support layer 125 as described above, an etching protection layer 152 is formed on the resultant. Etch protective layer 152 is preferably formed of a material that is not etched during the etching of the sacrificial layer 120 using subsequent hydrogen fluoride (HF) vapor, more preferably, plasma-enhanced chemical vapor deposition of amorphous silicon It forms using the (PECVD) method. Subsequently, the etch protection layer 152 is etched in the same pattern as the support layer 125 using a mask used when patterning the support layer 125.

Referring to FIG. 6G, the sacrificial layer 120 is etched using hydrogen fluoride (HF) vapor to form an air gap 160 at the position of the sacrificial layer 120. In this case, since the IsoCut portion is covered with an etch protective layer 152 made of a material (PECVD-amorphous silicon) that is not etched in the hydrogen fluoride vapor, hydrogen fluoride vapor is directed toward the active matrix 100 through the IsoCut portion. Penetration can be prevented.

Subsequently, the AMA device is completed by removing the etch protection layer 152 by a blanket dry etch method. In this case, since the thickness of the etch protection layer 152 formed on the stepped surfaces of the upper electrode 140 and the lower electrode 130 is relatively thicker than the thickness at other portions, the etch protection layer 152 is blanket-etched. Even after the removal by the method, the etching protection layer 152 remains on the stepped surfaces of the upper electrode 140 and the lower electrode 130. However, in the present invention, since the separation layer 138 made of oxide having high resistance is formed on the stepped surface of the strained layer 135 in the form of a spacer, the separation layer 138 is formed of the upper electrode 140 and the lower electrode ( 130 serves to independence. Therefore, an electrical short is not caused between the upper electrode 140 and the lower electrode 130. In addition, since the blanket etch amount of the etch protection layer 152 may be reduced by the separation layer 138, excessive etching of the etch stop layer 115 under the blanket etch process may be minimized.

In the above-described thin film type optical path control device according to the present invention, the first signal transmitted from the outside to the lower electrode 130 through the transistor, the drain pad 105 and the via contact 150 embedded in the active matrix 100. Is approved. At the same time, a second signal is applied to the upper electrode 140 from the outside to generate an electric field according to the potential difference 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 contracts in a direction orthogonal to the electric field, whereby the actuator 200 is bent at a predetermined angle. The upper electrode 140, which also functions as a mirror that reflects light, is formed on the actuator 200 and 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.

As described above, according to the present invention, the separation layer for reinforcing the IsoCut portion is formed in the form of a spacer on the stepped surface of the strained layer, thereby forming an etch formed to prevent hydrogen fluoride (HF) vapor from penetrating through the IsoCut portion. The protective layer may prevent an electrical short between the upper electrode and the lower electrode. In addition, since the lower electrode is deposited, the IsoCut process is omitted and the strained layer is deposited on the upper part, so that the strained layer made of piezoelectric material such as PZT is not a nitride layer but a metal layer (bottom electrode) such as platinum layer or tantalum layer. Only the deposition does not cause cracks in the interior of the strained layer during the heat treatment process for the phase change of the subsequent strained layer. Furthermore, since each pixel is connected to the upper electrode itself without a separate metal layer, structural stabilization of the AMA device can be obtained.

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 (6)

An active matrix (100) containing M × N (M, N is an integer) MOS transistors and including drain pads 105 extending from the drains of the transistors; And i) one side is in contact with the top of the active matrix 100 and the other side is formed horizontally via the air gap 160, ii) is formed on the top of the support layer 125 and each by the IsoCut part A lower electrode 130 separated for each pixel, and (i) a strained layer 135 formed on the lower electrode 130, and iv) a separated layer 138 formed on a step surface of the IsoCut portion and the strained layer 135. And (iii) an actuator having an etch protection layer 152 formed on the sidewalls of the separation layer 138 and an upper electrode 140 formed on the deformation layer 135. Device. The apparatus of claim 1, wherein the upper electrode is formed to overlap the boundary surface of the separation layer. The apparatus of claim 1, wherein the separation layer (138) is formed in a spacer form at a stepped surface of the deformation layer (135). Providing an active matrix comprising M × N (M, N is an integer) transistors and including drain pads extending from the drains of the transistors; Forming a sacrificial layer on top of the active matrix; And a) forming a support layer on top of the sacrificial layer, b) forming a bottom electrode on top of the support layer, c) forming a strained layer on top of the bottom electrode, d) forming a pixel on the strained layer Etching to a shape, e) isocutting the lower electrode for each pixel, f) forming a separation layer on the stepped surface of the isocut portion and the strained layer, g) forming an upper electrode on top of the strained layer Forming, h) etching the upper electrode to overlap the interface of the separation layer, i) etching the lower electrode in a pixel shape, j) electrically connecting the lower electrode and the drain pad to each other. Forming a via contact vertically from the strained layer to the drain pad, k) etching the support layer into a pixel shape, l) covering the IsoCut portion on top of the resultant Forming an etch protective layer so as to form an air gap by removing the sacrificial layer, and n) removing the etch protective layer by a blanket etching method. The manufacturing method of the thin film type optical path control apparatus characterized by the above-mentioned. 5. The method of claim 4, wherein the forming of the etch protective layer comprises performing the same pattern as the support layer. 6. The method of claim 5, wherein the forming of the etch protective layer is performed using plasma-enhanced chemical vapor deposition (PECVD).

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