KR19980046412A - Thin film type optical path adjusting device and its manufacturing method which can improve the light efficiency - Google Patents

Abstract

Disclosed are a thin film type optical path control device equipped with a mirror having a double layer and a method of manufacturing the same. The device includes an active matrix having M × N transistors formed therein and a drain formed on one side thereof, and a membrane formed so that one side is in contact with an upper portion of the active matrix and the other side is parallel to the active matrix via a first air gap. Ii) a lower electrode formed on top of the membrane to which an image signal is applied, iii) a strained layer stacked on top of the lower electrode to cause deformation according to an electric field, and iv) a biased voltage stacked on top of one side of the strained layer. A first mirror layer including an upper electrode to be applied, an actuator formed on an upper portion of the active matrix, and a central portion contacting an upper portion of one side of the upper electrode, the both sides being parallel to the upper electrode via a second air gap; And a mirror having a second mirror layer formed on top of the first mirror layer. The device minimizes the stress on the mirror surface by making the mirror a double layer of a first mirror layer that performs the function of reflecting light flux and a second mirror layer that facilitates the stress control of the mirror surface. Thereby preventing the mirror from twisting when the sacrificial layer is removed. Therefore, the reflection angle of the mirror can be made constant and the light efficiency of the light beam incident from the light source can be improved.

Description

Thin film type optical path control device and its manufacturing method which can improve the light efficiency

The present invention relates to AMA (Actuated Mirror Arrays) and a manufacturing method thereof, which is a thin film type optical path control device, and more particularly, by manufacturing a mirror having a double layer to control the stress of the mirror surface, thereby minimizing warping of the mirror The present invention relates to a thin-film optical path control device capable of making the reflection angle of a mirror constant and a manufacturing method thereof.

An optical path adjusting device or an optical modulator capable of adjusting the light flux may be variously applied to optical communication, image processing, and information display apparatus. In general, such devices are classified into two types according to their optical properties. One type is a direct view type image display device, such as a CRT (Cathode Ray Tube), and the other type is a projection type image display device, a liquid crystal display (LCD), a deformable mirror device (DMD), or an AMA. And the like. Although the CRT apparatus has excellent image quality, the weight and volume of the CRT apparatus increases, leading to an increase in manufacturing cost. On the other hand, the liquid crystal display (LCD) has a simple optical structure and can be formed thin so that the weight can be reduced and the volume can be reduced. However, the liquid crystal display device is inferior in efficiency to have a light efficiency of 1 to 2% due to polarization of light, has a disadvantage in that the response speed of the liquid crystal material is slow and the inside thereof is easily overheated.

Therefore, an image display device such as AMA or DMD has been developed to solve the above problem. Currently, AMA can achieve a light efficiency of 10% or more, compared to a DMD having a light efficiency of about 5%. The AMA is a device that can adjust the luminous flux so that each of the mirrors installed therein reflects the light flowing from the light source at a predetermined angle, and the reflected light passes through a slit to form an image on the screen. . Therefore, the structure and operation principle thereof are simple, and high light efficiency can be obtained compared to a liquid crystal display device or a DMD. In addition, the contrast can be improved to obtain a bright and clear image. The image is not affected by the polarity of the incident light beam and does not affect the polarity of the reflected light beam.

The mirrors embedded in the AMA are arranged to correspond to the slits, and the mirrors are inclined by an electric field generated inside the actuator. Therefore, the luminous flux incident from the light source is adjusted at a predetermined angle to form an image on the screen. In general, each actuator causes deformation in accordance with the electric field generated by the applied electric image signal and the bias voltage. When the actuator causes deformation, each of the mirrors mounted on top of the actuator is inclined. Accordingly, the inclined mirrors can reflect light incident from the light source at a predetermined angle. Piezoelectric materials such as PZT (Pb (Zr, Ti) O ₃ ) or PLZT ((Pb, La) (Zr, Ti) O ₃ ) are used as a constituent material of the deformable portion for driving the respective mirrors. In addition, a warping material such as PMN (Pb (Mg, Nb) O ₃ ) can be used as a constituent material of the deformation portion.

AMA, which is an optical path control device, is classified into a bulk device and a thin film device. The bulk optical path control device is disclosed, for example, in US Pat. Nos. 5,085,497 (issued to Gregory Um, et al.), 5,159,225 (issued to Gregory Um), 5,175,465 (issued to Gregory Um, et al.). It is. The bulk optical path adjusting device is to cut a thin layer of multilayer ceramic, mount a ceramic wafer having a metal electrode formed therein in an active matrix in which a transistor is built, and then process it by sawing and then It is constructed by installing a mirror. However, since the bulk light path control device must separate the actuators by a sawing method, high precision is required in design and manufacturing, and the response speed of the deformation part is slow. Therefore, a thin film type optical path control apparatus that can be manufactured using a semiconductor manufacturing process has been developed.

Such a thin film type optical path adjusting device is disclosed in Patent Application No. 96-64445 (name of the invention: a manufacturing method of a thin film type optical path adjusting device which can improve the light efficiency) which the applicant applied for a patent on December 11, 1996.

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

1 and 2, the thin film type optical path control apparatus includes an active matrix 31 and an actuator 49 formed on the active matrix 31. The active matrix 31 may include a drain 33 formed on one surface of the active matrix 31, a passivation layer 35 stacked on the active matrix 31 and the drain 33. And an etch stop layer 37 stacked on the protective layer 35.

The actuator 49 is stacked such that one side of the actuator is in contact with a portion of the etch stop layer 37 in which a drain 33 is formed at the bottom thereof, and the other side thereof is parallel to the etch stop layer 37 via the first air gap 55. A membrane 41, a bottom electrode 43 stacked on top of the membrane 41, an active layer 45 stacked on top of the bottom electrode 43, and a deformation layer ( The top electrode 47 stacked on one side of the top 45, the strained layer 45, the lower electrode 43, the membrane 41, the etch stop layer 37, and the protection from the other side of the strained layer 45. Via holes 51 formed vertically through the layer 35 to the drain 33, via contacts 53 formed in the via holes 51, and the upper electrode 47. The center portion is in contact with the upper portion of the upper side) and both sides include a mirror 59 formed to be parallel to the upper electrode 47 via the second air gap 61.

In addition, referring to FIG. 3, one side of the membrane 41 has a concave portion having a rectangular shape at the center thereof, and the concave portion is formed in a stepped shape toward both edges. The other side of the membrane 41 has a rectangular protrusion that narrows stepwise toward the central portion corresponding to the concave portion. Therefore, the recessed portion of the membrane of the actuator adjacent to the recessed portion of the membrane 41 is fitted, and the rectangular projection is fitted to the recessed portion of the adjacent membrane.

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

3A to 3G show a manufacturing process diagram of the apparatus shown in FIG. Referring to FIG. 3A, a protective layer 35 is stacked on an active matrix 31 having M × N MOS transistors (not shown) and having a drain 33 formed on one side thereof. The active matrix 31 is made of a semiconductor such as silicon or an insulating material such as glass or alumina (Al ₂ O ₃ ). The protective layer 35 is formed of Phospho-Silicate Glass (PSG) to have a thickness of about 1.0 to about 2.0 μm using a chemical vapor deposition (CVD) method. The protective layer 35 prevents the transistor embedded in the active matrix 31 from being damaged during subsequent processing.

An etch stop layer 37 is stacked on the passivation layer 35. The etch stop layer 37 is formed to have a thickness of about 1000 to 2000 kPa using a low pressure chemical vapor deposition (LPCVD) method. The etch stop layer 37 prevents the active matrix 31 and the protective layer 35 from being etched due to the subsequent etching process.

A sacrificial layer 39 is stacked on the etch stop layer 37. The sacrificial layer 39 is formed of phosphorous silicate (PSG) to have a thickness of about 1.0 to about 2.0 μm by an atmospheric pressure chemical vapor deposition (APCVD) method. Subsequently, a portion of the sacrificial layer 39 in which the drain 33 is formed is etched to expose a portion of the etch stop layer 37.

Referring to FIG. 3B, the membrane 41 is stacked on the exposed etch stop layer 37 and on the sacrificial layer 39. The membrane 41 is formed so as to have a thickness of about 0.1 to 1.0 탆 using a low pressure chemical vapor deposition (LPCVD) method. Subsequently, a lower electrode 43 made of platinum (Pt), platinum-tantalum (Pt-Ta), or the like is stacked on the membrane 41. The lower electrode 43 is formed to have a thickness of about 500 to 2000 microns using a sputtering method. An image signal is applied to the lower electrode 43, which is a signal electrode, from the transistor built in the active matrix 31 through the drain 33.

The strained layer 45 is stacked on the lower electrode 43. The strained layer 45 is formed into a piezoelectric material such as PZT or PLZT by using a Sol-Gel method or a chemical vapor deposition (CVD) method in the range of 0.1 to 1.0 µm, preferably 0. It is formed to have a thickness of about 4㎛. Next, the strained layer 45 is phase-shifted using the Rapid Thermal Annealing (RTA) method.

The upper electrode 47 is stacked on one side of the strained layer 45. The upper electrode 47 is formed to have a thickness of about 500 to 2000 micrometers by using a sputtering method of aluminum or platinum. The upper electrode 47 is applied with a bias voltage as a common electrode. Therefore, when an image signal is applied to the lower electrode 43 and a bias voltage is applied to the upper electrode 47, an electric field is generated between the upper electrode 47 and the lower electrode 43. This deformation causes the deformation layer 45 to deform. Subsequently, the upper electrode 47, the strain layer 45, and the lower electrode 43 are sequentially patterned.

Referring to FIG. 3C, the strained layer 45, the lower electrode 43, the membrane 41, the etch stop layer 37, from the other side of the strained layer 45 by using a conventional photolithography method. The protective layer 35 is sequentially etched to form a via hole 51. Therefore, the via hole 51 is vertically formed from the other side of the strained layer 45 to the drain 33. Subsequently, the via contact 53 is formed of a metal having excellent electrical conductivity such as tungsten (W) or titanium (Ti) using a sputtering method. The via contact 53 is electrically connected to the drain 33 and the lower electrode 43. Therefore, the image signal generated from the transistor embedded in the active matrix 31 is applied to the lower electrode 43 through the drain 33 and the via contact 53.

Referring to FIG. 3D, as described above, the upper electrode 47, the strained layer 45, the lower electrode 43, and the membrane 41 are sequentially patterned to partially form a thin film type AMA device, and then a sacrificial layer ( 39) is removed using hydrogen fluoride (HF) vapor. At this time, the membrane 41 is connected to each other without being separated for each actuator. Then, rinse and dry treatments are performed to remove the remaining etching solution.

Referring to FIG. 3E, a first photo resist 40 is applied to a portion where the sacrificial layer 39 is removed by spin coating to fill the portion where the sacrificial layer 39 is removed. -in) When the primary photoresist 40 is applied by spin coating, the portion where the sacrificial layer 39 is removed may be filled without empty space as described above.

Referring to FIG. 3F, after filling the primary photoresist 40 as described above, the membrane 41 is patterned to be separated by each actuator. Subsequently, a secondary photoresist 57 is applied on the top by spin coating. The secondary photoresist 57 is stacked on the upper electrode 47 at a predetermined thickness.

Referring to FIG. 3G, a portion of the secondary photoresist 57 is etched to form a support portion on which a mirror 59 is to be formed on one side of the upper electrode 47. Subsequently, aluminum, silver, or the like is sputtered on the upper portion of the secondary photoresist 57 on which the support portion is formed, and then patterned to form a mirror 59. The mirror 59 has a shape of a flat plate whose support portion is in contact with an upper portion of one side of the upper electrode 47, and both sides thereof are formed in parallel with the upper electrode 47 via a second air gap 61. The mirror 59 is formed such that one side covers the upper electrode 47 and the other side covers an adjacent actuator. Subsequently, after removing the primary photoresist 40 and the secondary photoresist 57 by an oxygen plasma (O ₂ plasma) method, the upper electrode 47, the strained layer 45, the lower electrode 43, The membrane 41 is sequentially completely patterned to have a predetermined pixel shape. When the primary photoresist 40 is removed, a first air gap 55 is formed, and when the secondary photoresist 57 is removed, a second air gap 61 is formed. The resulting product is washed and dried to complete the AMA device.

In the above-described thin film type optical path control device according to the present invention, the image signal transmitted from the transistor embedded in the active matrix 31 is transferred to the lower electrode 43 which is a signal electrode through the drain 33 and the via contact 53. Is approved. At the same time, a bias voltage is applied to the upper electrode 47, which is a common electrode, to generate an electric field between the upper electrode 47 and the lower electrode 43. The strained layer 45 between the upper electrode 47 and the lower electrode 43 causes deformation by this electric field. The strained layer 45 contracts in a direction perpendicular to the electric field, thereby causing the actuator 49 to bend in a direction opposite to the direction in which the membrane 41 is formed. The mirror 59 mounted on the upper electrode 47 of the actuator 49 is inclined by the curved upper electrode 47 to reflect the light beam incident from the light source. The light beam reflected by the mirror 59 is projected onto the screen through the slit to form an image.

However, in the above-described thin film type optical path adjusting device, since the mirror reflecting the light flux is made of a single layer of metal thin film such as aluminum or silver, the metal thin film itself forming the mirror is subjected to stress, thereby providing a second sacrificial layer. When removed, the mirror surface will bend. Therefore, since the mirror surface is not formed flat, there is a problem that the reflection angle of the light beam incident from the light source is not constant.

Accordingly, an object of the present invention is to provide a thin film type optical path control apparatus that can improve the light efficiency by forming a mirror having a layer that can control stress to improve the flatness of the mirror to make the reflection angle of the incident light beam constant.

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

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

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

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

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

6A to 6F are manufacturing process diagrams of the thin film type optical path adjusting device shown in FIG. 5.

Explanation of symbols for main parts of drawings>

131 ： active matrix 133 ： drain

135: protective layer 137: etching prevention layer

139: first sacrificial layer 143: lower electrode

145: strained layer 147: upper electrode

149 Actuator 151 Beer Hole

153: via contact 155: first air gap

157: second sacrificial layer 159: first mirror layer

161: second mirror layer 163: mirror

165: second air gap

In order to achieve the above object of the present invention, the present invention,

An active matrix in which M × N (M and N are integer) transistors are formed and a drain is formed on one side;

Iii) a membrane formed so that one side is in contact with an upper portion of the active matrix and the other side is parallel to the active matrix via a first air gap, ii) a lower electrode formed on the membrane to which an image signal is applied, iii) the A strained layer stacked on top of the lower electrode to cause deformation according to an electric field, i) an actuator formed on top of one side of the strained layer and applied with a bias voltage, the actuator formed on the active matrix; And

A central portion in contact with an upper portion of one side of the upper electrode, and a mirror having a first mirror layer formed in parallel with the upper electrode through a second air gap and a second mirror layer formed on the first mirror layer; It provides a thin film type optical path control device.

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

Iii) a lower electrode stacked on one side in contact with an upper portion of the active matrix and the other side parallel to the active matrix via a first air gap, and ii) a strained layer stacked on top of the lower electrode to cause deformation according to an electric field. (Iii) an upper electrode stacked on one side of the strained layer to which a bias voltage is applied, and iv) a center part contacted to an upper portion of one side of the upper electrode, and both sides formed in parallel with the upper electrode via a second air gap; Provided is a thin film type optical path control apparatus including an actuator having a mirror composed of a first mirror layer and a double layer of a second mirror layer formed on the first mirror layer.

In addition, the present invention to achieve the above object,

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

On the top of the active matrix, i) forming a membrane in parallel with the active matrix with one side contacting the top of the active matrix and the other side via a first air gap; ii) an image signal on the top of the membrane Forming a lower electrode to be applied, iii) forming a strained layer on top of the lower electrode according to an electric field, and iii) forming an upper electrode to which a bias voltage is applied on one side of the strained layer. Forming an actuator comprising a; And

Forming a first mirror layer in parallel with the upper electrode through a second air gap and having a central portion in contact with an upper portion of the upper electrode, and forming a second mirror layer formed on the first mirror layer; It provides a method of manufacturing a thin film type optical path control device comprising the step of forming a mirror comprising a step of.

In the above-described thin film type optical path control device according to the present invention, a bias voltage is applied to the upper electrode. At the same time, the image signal transmitted from the transistor embedded in the active matrix is applied to the lower electrode through the drain and via contact with the transistor embedded in the active matrix. Accordingly, an electric field is generated between the upper electrode and the lower electrode, and the strained layer between the upper electrode and the lower electrode causes deformation by this electric field. The strained layer contracts in a direction perpendicular to the electric field, so the actuator is bent in a direction opposite to the direction in which the lower electrode is formed at a predetermined angle. The mirror reflecting the light beam is inclined together with the actuator because it is formed on top of the actuator. Accordingly, the mirror reflects the light beam incident from the light source at a predetermined angle, and the reflected light beam passes through the slit to form an image on the screen.

Accordingly, the thin film type optical path adjusting device according to the present invention is manufactured by having a mirror having a double layer of a first mirror layer that performs a reflection function of reflecting a light beam incident from a light source and a second mirror layer of controlling the stress of the mirror surface. It is possible to minimize the distortion of the entire mirror by the stress of the surface, and thus to improve the light efficiency of the light beam incident from the light source by making the reflection angle of the mirror constant.

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

4 and 5, the thin film type optical path adjusting device according to the present invention includes an active matrix 131 and an active matrix 131 in which M × N (M and N are integers) metal oxide semiconductor (MOS) transistors are embedded. Actuator 149 formed on the top of the. The active matrix 131 may include the drain 133 formed on one surface of the active matrix 131, the protective layer 135 stacked on the active matrix 131 and the drain 133, and the protective layer 135. It includes an etch stop layer 137 stacked on top.

The actuator 149 has one side contacted to a portion of the etch stop layer 137 having a drain 133 formed on the bottom thereof, and the other side thereof is stacked in parallel with the etch stop layer 137 via the first air gap 155. The membrane 141, the lower electrode 143 formed on the membrane 141, the active layer 145 formed on the lower electrode 143, and the upper electrode formed on one side of the modified layer 145. 147, from the other side of the strained layer 145 to the drain 133 through the strained layer 145, the lower electrode 143, the membrane 141, the etch stop layer 137, and the protective layer 135. The via hole 151 is formed, the via contact 153 is formed so that the drain 133 and the lower electrode 143 are connected to the inside of the via hole 151, and the center portion is in contact with the upper portion of the upper electrode 147. Both sides include a mirror 163 formed to be parallel to the upper electrode 147 via the second air gap 165.

In addition, referring to FIG. 4, one side of the membrane 141 has a rectangular concave portion at the center thereof, and the concave portion is formed in a stepped shape toward both edges. The other side of the membrane 141 has a quadrangular protrusion that narrows stepwise toward the central portion corresponding to the concave portion. Therefore, the concave portion of the lower electrode of the actuator adjacent to the concave portion of the membrane 141 is fitted, and the rectangular protrusion is fitted to the concave portion of the adjacent lower electrode.

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

Referring to FIG. 6A, a protective layer 135 is stacked on an active matrix 131 having M × N MOS transistors (not shown) and having a drain 133 formed on one side thereof. The active matrix 131 is made of a semiconductor such as silicon (Si). In addition, the active matrix 131 may be formed of an insulating material such as glass or alumina (Al ₂ O ₃ ). The protective layer 135 is formed to have a thickness of about 0.01 to 1.0 μm using the phosphorus silicate glass (PSG) using a chemical vapor deposition (CVD) method. The protective layer 135 prevents the transistor embedded in the active matrix 131 from being damaged during the subsequent process.

An etch stop layer 137 is stacked on the passivation layer 135. The etch stop layer 137 is formed to have a thickness of about 1000 to 2000 GPa using a low pressure chemical vapor deposition (LPCVD) method. The etch stop layer 137 prevents the active matrix 131 and the protective layer 135 from being etched and damaged by the subsequent etching process.

The first sacrificial layer 139 is stacked on the etch stop layer 137. The first sacrificial layer 139 is formed of a silicate glass (PSG) to have a thickness of about 0.5 to about 2.0 μm by an Atmospheric Pressure Vapor Deposition (APCVD) method. Subsequently, a portion of the first sacrificial layer 139 in which the drain 133 is formed is etched to expose a portion of the etch stop layer 137.

Referring to FIG. 6B, the membrane 141 is stacked on the exposed etch stop layer 137 and on the first sacrificial layer 139. The membrane 141 is formed to have a thickness of about 0.1 to 1.0 탆 using low pressure chemical vapor deposition (LPCVD). Subsequently, a lower electrode 143 made of platinum (Pt), platinum-tantalum (Pt-Ta), or the like is stacked. The lower electrode 143 is used in a sputtering method in the range of 0.01 to 1. It is formed to have a thickness of about 0㎛. An image signal is applied to the lower electrode 143, which is a signal electrode, through the drain 133 from a transistor built in the active matrix 131. Subsequently, the lower electrode 143 is etched and patterned to separate each pixel. .

The strained layer 145 is stacked on the lower electrode 143. The strained layer 45 is formed into a piezoelectric material such as PZT or PLZT by using a Sol-Gel method or a chemical vapor deposition (CVD) method in the range of 0.1 to 1.0 µm, preferably 0. It is formed to have a thickness of about 4㎛. Subsequently, the strained layer 145 is phase-shifted using a rapid thermal annealing (RTA) method.

The upper electrode 147 is stacked on one side of the strained layer 145. The upper electrode 147 is formed from 0.1 to 1.1 by sputtering of aluminum or platinum. It is formed to have a thickness of about 0㎛. The upper electrode 147 is applied with a bias voltage as a common electrode. Therefore, when an image signal is applied to the lower electrode 143 and a bias voltage is applied to the upper electrode 147, an electric field is generated between the upper electrode 147 and the lower electrode 143. This deformation causes the strain layer 145 between the upper electrode 147 and the lower electrode 143 to deform.

Subsequently, the upper electrode 147, the strained layer 145, the lower electrode 143, and the membrane 141 are sequentially etched and patterned from an upper portion of the upper electrode 147.

Referring to FIG. 6C, the strained layer 145, the lower electrode 143, the membrane 141, the etch stop layer 137, and the other side of the strained layer 145 using a conventional photolithography method. The protective layer 135 is sequentially etched to form the via hole 151. Accordingly, the via hole 151 is vertically formed from the other side of the strained layer 145 to the drain 133. Subsequently, a via contact 153 is formed in the via hole 151 by sputtering a metal having excellent electrical conductivity such as tungsten (W) or titanium (Ti). The via contact 153 is electrically connected to the drain 133 and the lower electrode 143. Therefore, the image signal is applied to the lower electrode 143 through the drain 133 and the via contact 153 from the transistor embedded in the active matrix 131.

Referring to FIG. 6D, the first sacrificial layer 139 is etched with hydrofluoric acid (HF) vapor to form a first air gap 155 and is rinsed and dried to remove the remaining etching solution. The actuator 149 is completed by performing a process.

Referring to FIG. 6E, after forming the first air gap 155 as described above, the second sacrificial layer 157 is formed on the entire surface of the resultant. The second sacrificial layer 157 facilitates the mounting of the mirror 163 and improves the horizontality of the mirror 163, and is removed after the mirror 163 is mounted. Preferably, the second sacrificial layer 157 is formed by spin coating a photoresist made of a polymer having good fluidity, and the like, based on the upper electrode 147 while completely filling the first air gap 155. Apply to have a certain thickness. When the second sacrificial layer 157 is applied to the entire surface of the resultant formed actuator 149, the second sacrificial layer 157 is filled in the first air gap 155 to form a flat surface.

Referring to FIG. 6F, after forming the second sacrificial layer 157 as described above, the upper electrode 147 is formed by patterning the second sacrificial layer 157 using a photoresist (not shown) as a mask. One side of the mirror 163 is made of a support to be formed. Thus, the upper portion of one side of the upper electrode 147 is exposed. Subsequently, a first mirror layer 159 is formed on the second sacrificial layer 157 and the exposed upper electrode 147 on which the supporting part is formed. The first mirror layer 159 is formed of a nitride such as silicon nitride (Si ₃ N ₄ ) to have a thickness of about 0.1 to 1.0 μm using a low pressure chemical vapor deposition (LPCVD) method. . The first mirror layer 159 may prevent the mirror surface from twisting by adjusting the stress of the mirror surface.

Subsequently, a second mirror layer 161 is formed on the first mirror layer 159. The second mirror layer 161 is formed by depositing a metal such as aluminum (Al), silver (Ag), or platinum with good reflectivity to a thickness of about 0.01 to 1.0 탆 using a sputtering process. The mirror 163 has a shape of a flat plate whose support portion is in contact with an upper portion of one side of the upper electrode 147, and both sides thereof are formed in parallel with the upper electrode 147 via a second air gap 165. The mirror 163 is formed such that one side covers the upper electrode 147 and the other side covers an adjacent actuator. Conventionally, when a mirror is formed of one metal layer to form a mirror and then the sacrificial layer is etched, distortion of the mirror surface is likely to occur. However, in the present invention, as described above, the mirror of the double-layer structure of the first mirror layer 159 to reflect the light flux and the second mirror layer 161 to facilitate the stress control of the mirror surface By producing 163, the mirror surface can be prevented from twisting, so that the reflection angle of the mirror can be made constant. After forming the mirror 163 as described above, the second sacrificial layer 157 is removed with an oxygen plasma (O ₂ plasma) for separation between pixels, and rinsing and drying are performed. As a result, the second air gap 165 is formed between the mirror 163 and the upper electrode 147, thereby completing the complete actuator 149 with the mirror 163 mounted thereon.

After completing the M × N thin film type AMA devices as described above, the active matrix 131 is formed by evaporation or sputtering a metal such as chromium (Cr), copper (Cu), or gold (Au). It is deposited at the bottom of the to form an ohmic contact (not shown). In addition, a TCP (Tape Carrier Package) (not shown) bonding is applied to apply a bias voltage to a subsequent upper electrode 147, which is a common electrode, and an image signal to a lower electrode 143, which is a signal electrode. To cut the active matrix 100 using a conventional photolithography method. In this case, the active matrix 131 is cut only to a predetermined thickness in preparation for the subsequent process. Subsequently, a photoresist layer (not shown) is formed on the pad (not shown) of the AMA panel so as to have a sufficient height in preparation for TCP bonding, and then a portion where the pad is formed below the photoresist layer is formed. Patterning exposes the pads of the AMA panel. After that, the photoresist layer is removed. Subsequently, the active matrix 131 on which the thin film type AMA element is formed is completely cut out into a predetermined shape, and then the pad of the AMA panel and the TCP pad are connected with an anisotropic conductive film (ACF) (not shown) to manufacture the thin film type AMA module. To complete.

In the above-described thin film type optical path control device according to the present invention, an image signal transmitted from a transistor embedded in the active matrix 131 through a pad of TCP and a pad of an AMA panel is transferred through a drain 133 and a via contact 153. The lower electrode 143 is applied to the signal electrode. At the same time, a bias voltage is applied to the upper electrode 147, which is a common electrode, to generate an electric field between the upper electrode 147 and the lower electrode 143. The strained layer 145 between the upper electrode 147 and the lower electrode 143 causes deformation by this electric field. The strained layer 145 is contracted in a direction perpendicular to the electric field, and thus the actuator 149 is bent in a direction opposite to the direction in which the lower electrode 143 is formed. The mirror 163, which is mounted on the upper electrode 147 of the actuator 149 and has a double layer of the first mirror layer 159 and the second mirror layer 161, is inclined by the curved upper electrode 147 to be inclined. Reflects the light beam incident from the beam. The light beam reflected by the mirror 163 is projected onto the screen through the slit to form an image.

Therefore, the thin film type optical path adjusting device according to the present invention is a mirror having a double layer of a first mirror layer that performs a function of reflecting the light beam incident from the light source and a second mirror layer of a function that facilitates stress control of the mirror surface. By fabricating, the flatness of the mirror surface can be improved by preventing the mirror from twisting while removing the sacrificial layer. Therefore, the light efficiency of the light beam incident from the light source can be improved by making the reflection angle of the mirror constant.

Although the above has been described 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 (10)

An active matrix 131 in which M × N (M and N are integer) transistors are formed and a drain 133 is formed on one side; Iii) a membrane 141 formed to be in contact with an upper portion of the active matrix 131 and the other side to be parallel to the active matrix 131 via a first air gap 155, ii) of the membrane 141 A lower electrode 143 formed on the upper side and a lower electrode 143 to which an image signal is applied, (v) a strained layer 145 stacked on top of the lower electrode 143 to cause deformation according to an electric field, and An actuator 149 which is stacked on and includes an upper electrode 147 to which a bias voltage is applied, and formed on the active matrix 131; And The first mirror layer 159 and the first mirror layer (1) formed in parallel with the upper electrode 147 through the second air gap 165 with a central portion in contact with an upper portion of one side of the upper electrode 147 ( Thin film type optical path control device comprising a mirror (163) having a second mirror layer (161) formed on top of. The protective layer 135 formed on the active matrix 131 and the drain 133 and the etch stop layer 137 formed on the protective layer 135 are formed on the active matrix 131. The actuator 149 further includes the strained layer 145, the lower electrode 143, the membrane 141, the etch stop layer 137, and the protection from the other side of the strained layer 145. The via hole 151 perpendicular to the drain 133 through the layer 135 and the via contact formed to electrically connect the lower electrode 143 and the drain 133 to the inside of the via hole 151. Thin film type optical path control device, characterized in that it further comprises (153). 2. The thin film type optical path adjusting device according to claim 1, wherein the first mirror layer (159) deposits nitride with a thickness of 0.1 to 1.0 mu m. The thin film type optical path of claim 1, wherein the second mirror layer 161 deposits aluminum (Al), silver (Ag), or platinum (Pt) to a thickness of 0.1 to 1.0 탆. Regulator. Providing an active matrix having M × N transistors embedded therein and having a drain formed on one side thereof; On the top of the active matrix, i) forming a membrane in parallel with the active matrix with one side contacting the top of the active matrix and the other side via a first air gap; ii) an image signal on the top of the membrane Forming a lower electrode to be applied, iii) forming a strained layer on top of the lower electrode according to an electric field, and iii) forming an upper electrode to which a bias voltage is applied on one side of the strained layer. Forming an actuator comprising a; And Forming a first mirror layer in parallel with the upper electrode through a second air gap and having a central portion in contact with an upper portion of the upper electrode, and forming a second mirror layer formed on the first mirror layer; Method of manufacturing a thin film type optical path control device comprising the step of forming a mirror comprising a step. 6. The method of claim 5, wherein providing the active matrix comprises: i) forming a protective layer over the active matrix and the drain, ii) forming an etch stop layer over the protective layer; And forming a sacrificial layer on top of the etch stop layer, followed by etching and patterning the sacrificial layer so that a portion of the etch stop layer is exposed. The method of claim 5, wherein the forming of the actuator comprises: i) patterning the upper electrode, the strain layer, and the lower electrode sequentially from the top, ii) the strain layer, the lower electrode, and the second side from the other side of the strain layer. Etching the membrane to form a via hole vertically from the strained layer to the drain, and iii) forming a via contact in the via hole to electrically connect the drain and the lower electrode. The manufacturing method of the thin film type optical path control apparatus. The method of claim 5, wherein the forming of the mirror comprises: applying a photoresist on the upper electrode and the deforming layer, and patterning a portion of the photoresist to expose an upper portion of the upper electrode. The manufacturing method of the thin film type optical path control apparatus characterized by the above-mentioned. The method of claim 5, wherein the forming of the first mirror layer is performed by using a low pressure chemical vapor deposition (LPCVD) method. The method of claim 5, wherein the forming of the second mirror layer is performed using a sputtering process of aluminum (Al), silver (Ag), or platinum (Pt).