KR100256872B1 - Thin flim actuated mirror array for preventing the initial deflection of the actuator and method for manufacturing the same - Google Patents

Abstract

PURPOSE: A thin-film micromirror array-actuated(TMA) for preventing initial tilting of actuator and manufacturing method thereof support an actuator with an actuator supporting part and a spring bar, thereby preventing the initial tilting of the actuator, and restoring to the initial driving angle due to the restoring force of the spring bar. CONSTITUTION: A square stick-shaped spring bar(135) is arranged in both sides of an actuator(170) in the longitudinal direction. One side of the spring bar(135) is supported by a spring bar supporting part(137) formed corresponding to an actuator supporting part(131) and the other side of the spring bar(135) bent double contacts with the both sides of the actuator(170). The height of the spring bar(137) is equal to that of the actuator supporting part(131). The length and the width of the spring bar(135) are adjustable to control the driving angle of the actuator(170). Exactly, in case the length of the spring bar(135) becomes short, the driving angle of the actuator(170) is decreased and in case the length of the spring bar(135) becomes long, the driving angle of the actuator(170) is increased. Also, in case the width of the spring bar(135) becomes wide, the driving angle of the actuator(170) is reduced.

Description

Thin-film optical path control device capable of preventing initial tilt of actuator and manufacturing method thereof

The present invention relates to an Actuated Mirror Array (AMA), which is a thin film type optical path adjusting device, and a method of manufacturing the same, and more particularly, by forming a spring bar on one side of the actuator, which is in contact with one side thereof, to prevent initial tilt of the actuator. The present invention relates to a thin film type optical path adjusting device capable of uniformly controlling the driving angle of an actuator, and a manufacturing method thereof.

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. An image processing apparatus using such an optical path adjusting device or a spatial light modulator typically has a direct-view image display device and a projection-type image device according to a method of displaying optical energy on a screen. display device).

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

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

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

Each actuator of the AMA generates a deformation in accordance with the electric field generated by the applied electric picture signal and the bias signal. As the actuator deforms, each of the mirrors mounted on top thereof is inclined. Accordingly, the inclined mirrors reflect light incident from the light source at a predetermined angle according to the magnitude of the electric field, thereby forming an image on the screen. As an actuator for driving the respective mirrors, piezoelectric materials such as PZT (Pb (Zr, Ti) O ₃ ) or PLZT ((Pb, La) (Zr, Ti) O ₃ ) are used. In addition, an actuator may be formed as a warping material such as PMN (Pb (Mg, Nb) O ₃ ).

These AMA devices are largely divided into bulk type and thin film type. Bulk light path control devices are disclosed in US Pat. No. 5,085,497 to Gregory Um et al. The bulk optical path adjusting device is made by thinly cutting a multilayer ceramic to mount a ceramic wafer having a metal electrode formed therein in an active matrix in which a transistor is embedded, and then processing by a sawing method and installing a mirror thereon. However, the bulk optical path control device requires very high precision in design and manufacture, and has a disadvantage in that the response of the deformable part is slow.

Accordingly, a thin film type optical path control apparatus that can be manufactured using a semiconductor manufacturing process has been developed. Such a thin film type optical path control device is disclosed in Korean Patent Application No. 96-52681 (name of the invention: a method of manufacturing a thin film type optical path control device) filed by the applicant of the Korean Patent Office on November 7, 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 device includes an active matrix 1 and an actuator 50 formed on the active matrix 1.

In the active matrix 1, M x N (M, N is an integer) MOS transistors (not shown) are built in, and a drain pad 5 is formed on one side thereof. In addition, the active matrix 1 includes a protective layer 10 formed on the active matrix 1 and the drain pad 5, and an etch stop layer 15 formed on the protective layer 10.

The actuator 50 has a cross-section formed at one side thereof in contact with the etch stop layer 15 having the drain pad 5 formed thereon and the other side formed in parallel with the lower portion of the active matrix 1 via the air gap 25. The membrane 30 having, the lower electrode 35 formed on the membrane 30, the strain layer 40 formed on the lower electrode 35, the upper electrode 45 stacked on the strain layer 40 And a via contact 65 formed to connect the lower electrode 35 and the drain pad 5 in the via hole 60 formed vertically from one side of the strained layer 40 to an upper portion of the drain pad 5. do.

Hereinafter, the manufacturing method of the thin film type optical path control apparatus mentioned above is demonstrated.

First, a protective layer 10 is stacked on top of an active matrix 1 having M × N MOS transistors (not shown) and a drain pad 5 formed on one side thereof. The protective layer 10 is formed of Phosphor-Silicate Glass (PSG) using a chemical vapor deposition (CVD) method. The protective layer 10 prevents damage to the active matrix 1 in which the transistor is embedded during subsequent processing.

An etch stop layer 15 is formed on the passivation layer 10. The etch stop layer 15 is formed of nitride by using a low pressure chemical vapor deposition (LPCVD) method. The etch stop layer 15 prevents the active matrix 1 and the protective layer 10 from being etched during subsequent processes.

The sacrificial layer 20 is formed on the etch stop layer 15. The sacrificial layer 20 is formed of amorphous silicon using a sputtering method. Subsequently, a portion of the sacrificial layer 20 in which the drain pad 5 is formed is etched in consideration of the position where the support portion of the actuator 50 is to be formed to expose a portion of the etch stop layer 15.

The membrane 30 is formed on the exposed etch stop layer 15 and on the sacrificial layer 20. The membrane 30 is formed of a nitride using a sputtering method. The lower electrode 35 made of a metal such as aluminum (Al) or platinum (Pt) is formed on the membrane 30. The lower electrode 35 is stacked using a sputtering method. Subsequently, the lower electrode 35 is iso-cutted so as to apply an independent first signal (image signal) for each pixel. The first signal is applied to the lower electrode 35 through the transistor, the drain pad 5, and the via contact 65 embedded in the active matrix 1.

The strained layer 40 is formed on the lower electrode 35. The strained layer 40 is formed using a sputtering method of ZnO. Subsequently, an upper electrode 45 is formed on the strained layer 40. The upper electrode 45 is formed of aluminum (Al) or silver (Ag) using a sputtering method. The upper electrode 45 functions as a bias electrode to which a second signal (bias signal) is applied to generate an electric field, and a mirror to reflect light incident from a light source.

Subsequently, the upper electrode 45 is patterned to have a predetermined pixel shape. In this case, a part of the upper electrode 45 may be made to uniformly operate the upper electrode 45 so that light incident from a light source causes deformation of the upper electrode 45 according to the deformation of the strained layer 40. A stripe 55 is formed to prevent diffuse reflection at the boundary of the portion that is not deformed. The strained layer 40 and the lower electrode 35 are each patterned to have a predetermined pixel shape.

The strained layer 40, the lower electrode 35, the membrane 30, the etch stop layer 15, and the protective layer 10 are sequentially etched from one side of the strained layer 40 so that a portion of the drain pad 5 may be etched. The via hole 60 is formed to be exposed. Subsequently, a via contact 65 is formed in the via hole 60 so that the lower electrode 35 and the drain pad 5 are connected by sputtering a metal such as tungsten (W) or titanium (Ti). Accordingly, since the lower electrode 35 and the drain pad 5 are electrically connected to each other through the via contact 65, the transistor, the drain pad 5, and the via embedded in the active matrix 1 are connected to the lower electrode 35. The first signal may be applied through the contact 65. Subsequently, after the membrane 30 is patterned to have a predetermined pixel shape, the sacrificial layer 20 is etched using hydrogen fluoride (HF) vapor, washed and dried to complete a thin film type optical path control device. . When the sacrificial layer 20 is removed, an air gap 25 is formed at the position of the sacrificial layer 20.

In the above-described thin film type optical path adjusting device, the first signal transmitted from the outside is applied to the lower electrode 35 through the transistor, the drain pad 5, and the via contact 65 embedded in the active matrix 1. On the other hand, since the same second signal is applied to the upper electrode 45 for each of the upper electrodes of each actuator from the outside, an electric field is generated according to the potential difference between the upper electrode 45 and the lower electrode 35. Due to this electric field, the deformation layer 40 causes deformation. The strained layer 40 contracts in a direction orthogonal to the electric field, the lower part of which is limited to contraction by the formed membrane 30, and one side thereof is structurally fixed to the active matrix 1 so that the actuator 50 is consequently It is bent upward at a predetermined angle. Since the upper electrode 45 formed on the actuator 50 also functions as a mirror, the upper electrode 45 is inclined according to the deformation of the deformation layer 40. Therefore, the light incident from the light source is reflected by the upper electrode 45 inclined 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, after removing the sacrificial layer temporarily formed during the process to form the air gap, the stress of the residual stress and the stress distribution between the layers stacked in a single pixel is removed. due to the gradient, there is a significant amount of initial tilt of the actuator. If the initial tilt of the actuator occurs, there is a problem that the contrast of the image projected on the screen is reduced by becoming gray on a system configured to maintain normal black (or white) in the state where no signal is applied. Furthermore, after the actuator is driven, there is a problem that it becomes more difficult to control the driving angle of the actuator by hysteresis of the PZT constituting the deformation layer.

Accordingly, an object of the present invention is to form a spring bar on one side of the actuator, which is in contact with one side thereof, to uniformize the initial tilt of the actuator, and to return the actuator to the initial state even after the signal is applied and the actuator is driven. It is to provide a thin film type optical path control device and a method of manufacturing the same.

1 is a plan view of a membrane of the thin film optical path control 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.

3 is a plan view of the support layer of the 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 ′.

5A to 5D are manufacturing process diagrams of the apparatus shown in FIGS. 3 and 4.

<Explanation of symbols for main parts of drawing>

100: active matrix 105: first metal layer

110: first protective layer 115: second metal layer

120: second protective layer 125: etch stop layer

130: victim layer 131: actuator support portion

135: spring bar 137: spring bar support

140: support layer 145: lower electrode

150: strained layer 155: upper electrode

160: Beer hall 165: Beer contact

170: Actuator 175: air gap

In order to achieve the above object, the present invention includes an active matrix including a first metal layer containing M x N (M, N is an integer) transistor, the drain pad extending from the drain of the transistor; Iii) a support layer formed on top of the first metal layer and the active matrix, ii) a bottom electrode formed on top of the support layer, iii) a strained layer formed on top of the bottom electrode, and iii) a top formed on top of the strained layer. An actuator comprising an electrode; And it is provided with a thin film type optical path control device including a spring bar formed on the side is in contact with each side of the actuator and the other side is formed by a spring bar support formed on a portion corresponding to the actuator support.

In addition, to achieve the above object, the present invention includes the step of forming a first metal layer containing M × N (M, N is an integer) transistor, the drain pad extending from the drain of the transistor; Providing an active matrix; Forming a sacrificial layer over the first metal layer and over the active matrix; Patterning the sacrificial layer to expose both sides of the portion where the drain pad is formed in the active matrix in the shape of a rectangle, and exposing portions corresponding to the portion where the drain pad is formed in the shape of a rectangle; Forming an actuator support and a spring bar support on top of the exposed sacrificial layer; Sequentially forming a first layer, a lower electrode layer, a second layer, and an upper electrode layer on the actuator support, the spring bar support, and the sacrificial layer; And forming an upper electrode by patterning the upper electrode layer, forming a strained layer by patterning the second layer, forming a lower electrode by patterning the lower electrode layer, and patterning the first layer. And it provides a method of manufacturing a thin film type optical path control device comprising the step of forming an actuator comprising the step of forming a spring bar.

In the above-described thin film type optical path control device, the first signal transmitted from the outside, that is, the image signal, is applied to the lower electrode through the transistor, the drain pad, and the via contact embedded in the active matrix. On the other hand, since the same second signal, that is, a bias signal is always applied to the upper electrode of each actuator from the outside, an electric field is generated 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, the lower part of which is limited in shrinkage by the formed support layer, and one side is structurally fixed to the active matrix so that the actuator including the strained layer has a predetermined angle upwards. Bent. The upper electrode, which also functions to reflect light incident from the light source, is formed on the actuator and is inclined together 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.

However, in the above-described thin film type optical path adjusting device according to the present invention, spring bars which one side thereof is in contact with both sides of the actuator are formed. Therefore, the actuator is not only supported on one side by the actuator support, but also supported by the spring bar, so that the actuator is substantially supported in four parts. Therefore, initial tilting of the actuator can be prevented, and the actuator can be formed horizontally and stably. Moreover, after the image signal is applied and the actuator is driven, the restoring force of the spring bar is returned to the driving angle close to the initial driving angle before the next image signal is applied. Therefore, the reproducibility of the drive angle of the actuator can be improved.

Hereinafter, a thin film type optical path adjusting apparatus according to the present invention will be described in detail with reference to the accompanying drawings.

Figure 3 shows a plan view of the support layer of the thin film type optical path control apparatus according to the present invention, Figure 4 shows a cross-sectional view taken by the line B ­ B '.

3 and 4, in the thin film type optical path adjusting apparatus according to the present invention, one side is in contact with both sides of the active matrix 100, the actuator 170 formed on the active matrix 100, and the actuator 170. And a spring bar 135 supporting the actuator.

Referring to FIG. 4, the active matrix 100 in which M × N (M, N is an integer) MOS transistors is formed, the first metal layer extending from the drain and source of the MOS transistor and formed on the active matrix 100. 105, a first passivation layer 110 formed on the first metal layer 105, a second metal layer 115 formed on the first passivation layer 110, and a second metal layer 115 formed on the top of the first metal layer 105. The second protective layer 120 and the etch stop layer 125 formed on the second protective layer 120 is included.

The first metal layer 105 extends from the drain region of the transistor and includes a drain pad for transmitting a first signal (image signal) to the lower electrode 145.

The actuator 170 may be in contact with a portion of the etch stop layer 125 at which a drain pad of the first metal layer 105 is formed, and the other side thereof may be parallel to a lower portion of the active matrix 100 via an air gap 175. The support layer 140 includes a lower electrode 145 formed on the support layer, a strain layer 150 stacked on the lower electrode, and an upper electrode 155 stacked on the strain layer. In addition, the actuator 170 may include the via hole 160 vertically formed from one side of the strained layer 150 to the drain pad of the first metal layer 105, and the via contact 165 formed inside the via hole 160. Include. The lower electrode 145 is electrically connected to the drain pad of the first metal layer 105 through the via contact 165.

The spring bar 135 has a rectangular bar shape and is formed on both sides of the actuator in parallel to the actuator in the longitudinal direction of the actuator 170. Each of the spring bars 135 is supported by a spring bar support part 137 formed at a portion corresponding to the actuator support part 131, and the other side of the spring bar 135 is bent in a '-' shape to be in contact with both sides of the actuator 170. An air gap 175 is interposed between the spring bar 135 and the active matrix 100 and is formed in parallel with the support layer 140 on the same plane as the support layer 140. The spring bar support 137 has the same height as the actuator support 131.

In addition, referring to FIG. 3, one side of the support layer 140 is formed in a shape having a rectangular concave portion at the center thereof. In addition, the other side of the support layer 140 has a protrusion having a rectangular shape corresponding to the concave portion. Therefore, the protruding portion of the support layer of the actuator adjacent to the concave portion of the support layer 140 is fitted, and the rectangular projection is fitted into the concave portion of the support layer of the adjacent actuator. The support layer 140 performs the function of a membrane in the thin film optical path control device described in the previous application.

Hereinafter, the manufacturing method of the thin film type optical path control device according to the present embodiment.

5A to 5D are manufacturing process diagrams of the apparatus shown in FIGS. 3 and 4. In Figs. 5A to 5D, the same reference numerals are used for the same members as Figs. 3 and 4.

Referring to FIG. 5A, after forming the first metal layer 105 on the active matrix 100 having M × N MOS transistors therein, the first metal layer 105 is patterned and the MOS transistors below it. To expose the gate region. Thus, the first metal layer 105 is connected to the drain and the source of the MOS transistor. The active matrix 100 is made of a semiconductor such as silicon (Si) or an insulating material such as glass or alumina (Al ₂ O ₃ ). The first metal layer 105 is composed of tungsten, titanium, titanium nitride, or the like, and includes a drain pad extending from the drain region of the transistor to an actuator support portion 131 formed later. The first signal applied from the outside is transferred to the lower electrode 145 through the MOS transistor embedded in the active matrix 100 and the drain pad of the first metal layer 105.

The first passivation layer 110 is formed on the first metal layer 105 including the active matrix 100 and the drain pad by using Phosphor-Silicate Glass (PSG). The first protective layer 110 is 0.8 to 1. using a chemical vapor deposition (CVD) method. It is formed to have a thickness of about 0㎛. The first protective layer 110 prevents damage to the active matrix 100 in which the transistor and drain pads are formed during subsequent processes.

The second metal layer 115 is formed on the first protective layer 110. The second metal layer 115 is first sputtered with titanium to form a titanium layer having a thickness of about 300 to 500 kPa. Then, it completes by forming a titanium nitride layer using titanium nitride (TiN) on an upper part of a titanium layer. The titanium nitride layer is formed to have a thickness of about 1000 to 1200 하여 using physical vapor deposition (PVD). The second metal layer 115 prevents light leakage current from flowing through the active matrix 100 because light incident from the light source is also incident to portions other than the portion where the upper electrode 155 is formed. . Subsequently, a portion of the second metal layer 115 is etched to form an opening 117 in a portion in which the drain pad is formed below the second metal layer 115.

The second passivation layer 120 is formed on the second metal layer 115. The second passivation layer 120 is 0.2-0. 0 using a chemical vapor deposition method. It is formed to have a thickness of about 4㎛. The second protective layer 120 is formed using phosphorus silicate glass PSG. The second protective layer 120 prevents damage to the active matrix 100 in which the transistor and drain pads are formed during subsequent processes.

An etch stop layer 125 is stacked on the second passivation layer 120. The etch stop layer 125 is formed to have a thickness of about 1000 ~ 2000Å using nitride. The etch stop layer 125 is formed using a low pressure chemical vapor deposition (LPCVD) method. The etch stop layer 125 prevents the second passivation layer 120 and the active matrix 100 from being etched and damaged during the subsequent etching process.

The sacrificial layer 130 is stacked on the etch stop layer 125 by using a silicate glass (PSG), a metal, or an oxide. The sacrificial layer 130 is formed to have a thickness of about 2.0 to 3.0 μm using an Atmospheric Pressure Vapor Deposition (APCVD) method, a sputtering method, or an evaporation method. The sacrificial layer 130 performs a function of facilitating the stacking of thin films for forming the actuator 170. In this case, since the sacrificial layer 130 covers the top of the active matrix 100 in which the transistors and the drain pads are formed, the surface flatness is very poor. Therefore, the surface of the sacrificial layer 130 is planarized by using a spin on glass (SOG) method or a chemical mechanical polishing (CMP) method.

Subsequently, both sides of the portion of the sacrificial layer 130 where the drain pad of the first metal layer 105 is formed are patterned in a square shape to expose a portion of the etch stop layer 125 to expose the actuator support 131. Make At the same time, both sides of the portion of the sacrificial layer 130 corresponding to the portion where the actuator support portion 131 is to be formed are patterned into a quadrangular shape having a narrower width than the actuator support portion 131 to expose a portion of the etch stop layer 125. Let's do it.

Referring to FIG. 5B, the first layer 139 is stacked using a rigid material, for example, nitride or metal, on the exposed etch stop layer 125 and on the sacrificial layer 130. The first layer 139 is formed to have a thickness of about 0.01 to 1.0 탆 using low pressure chemical vapor deposition (LPCVD). At this time, the hard material is deposited while filling the inside of the sacrificial layer 130 patterned to form the actuator support 131 and the spring bar support 137. Accordingly, the actuator support 131 and the spring bar support 137 are formed using the same material as the first layer 139 while the first layer 139 is formed. The first layer 139 is later patterned into a support layer 140 having a predetermined pixel shape.

The lower electrode layer 144 is stacked on the first layer 139. The lower electrode layer 144 is formed using platinum (Pt), tantalum (Ta), or platinum-tantalum (Pt-Ta), which is a metal having electrical conductivity. The lower electrode layer 144 is formed to have a thickness of about 0.01 to 1.0 μm using a sputtering method or a chemical vapor deposition method. Subsequently, the lower electrode layer 144 is iso-cutted to apply an independent first signal for each pixel. The lower electrode layer 144 is later patterned into the lower electrode 145.

The second layer 149 is stacked on the lower electrode layer 144. The second layer 149 is formed using a piezoelectric material such as ZnO, PZT, or PLZT to have a thickness of about 0.01 to 1.0 탆. The second layer 149 is formed using a sol-gel method, a sputtering method, or a chemical vapor deposition (CVD) method, and then heat-treated using a rapid thermal annealing (RTA) method. Phase change Since the second layer 149 has a thickness of 1.0 μm or less, a separate poling process is not necessary. The second layer 149 is later patterned into the strained layer 150.

The upper electrode layer 154 is formed on the second layer 149. The upper electrode layer 154 is formed using a metal having electrical conductivity such as aluminum (Al), platinum, or silver (Ag). The upper electrode layer 154 is formed to have a thickness of about 0.01 to 1.0 탆 using a sputtering method or a chemical vapor deposition method.

Referring to FIG. 5C, after the photoresist (not shown) is coated on the upper electrode layer 154, the upper electrode layer 154 is patterned using the photoresist as an etching mask to form the upper electrode 155. . The photoresist is then removed. The second signal is applied to the upper electrode 155 from a common line (not shown). The second signal is a bias signal.

The second layer 149 and the lower electrode layer 144 are also patterned using the same method as the patterning of the upper electrode layer 154. The second layer 149 is patterned as the strained layer 150, and the lower electrode layer 144 is patterned as the lower electrode 145. The strained layer 150 has the same shape as the upper electrode 155 and has a slightly larger area than the upper electrode 155. In addition, the lower electrode 145 also has the same shape as the upper electrode 155 and has a slightly larger area than the deformation layer 150.

Next, one side of the strained layer 150, the lower electrode 145, the first layer 139, the etch stop layer 125, the second passivation layer 120, and the first passivation layer 110 are sequentially etched to form a via hole. To form 160. Accordingly, the via hole 160 is formed from one side of the strained layer 150 to an upper portion of the drain pad of the first metal layer 105 through the opening 117 of the second metal layer 115. Subsequently, a metal having excellent electrical conductivity such as tungsten (W), aluminum, or titanium (Ti) is deposited in the via hole 160 by using a sputtering method to form the via contact 165, and then patterning the via contact 160. The via contact 165 electrically connects the drain pad and the lower electrode 145. Therefore, the first signal applied from the outside is applied to the lower electrode 145 through the transistor, the drain pad of the first metal layer 105, and the via contact 165.

Subsequently, the first layer 139 is patterned to form a support layer 140 having a predetermined pixel shape. In this case, the support layer 140 has a slightly larger area than the lower electrode 145. At the same time, one side of the both sides of the support layer 140 adjacent to the actuator support part 131 is in contact with the side of the support layer 140 in the pattern of a bar (bar) patterned to form a spring bar 135. . The spring bar 135 is formed in parallel with the support layer 140 on both sides of the support layer 140 on the same plane as the support layer starting from the spring bar support 137, and one side is bent in a '-' shape to support the layer 140. It is formed integrally with (see Fig. 3).

The spring bar 135 may adjust its length and width as necessary to control the driving angle of the actuator 170. That is, when the support layer 140 is patterned, the actuator 170 may be adjusted by adjusting the length of the spring bar 135 by adjusting the position where the bent portion of the spring bar 135 is in contact with the support layer 140. To control the driving angle. In this case, as the length of the spring bar 135 is shorter, the restoring force of the spring bar 135 is increased, so that the driving angle of the actuator is reduced. On the contrary, as the length of the spring bar 135 is longer, the restoring force of the spring bar 135 is somewhat reduced, so that the driving angle of the actuator is increased. In addition, as the width of the spring bar 135 is wider, the restoring force is increased, thereby reducing the driving angle of the actuator.

The first signal, that is, an image signal, is applied to the lower electrode 145 through the transistor, the drain pad, and the via contact 165 formed in the active matrix 100. Therefore, when the first signal is applied to the lower electrode 145 and the second signal is applied to the upper electrode 155, an electric field is generated between the upper electrode 155 and the lower electrode 145. The deformation layer 150 causes deformation by this electric field.

Referring to FIG. 5D, the sacrificial layer 130 is removed using hydrogen fluoride (HF) vapor. When the sacrificial layer 130 is removed, the air gap 175 is formed at the position of the sacrificial layer 130 to complete the actuator 170. The actuator 170 formed as described above is supported not only by the actuator support part 131 but also by a spring bar 135 having one side integrally formed thereon. Therefore, since the actuator 170 is substantially supported by four places, the level of the actuator can be much improved as compared with the conventional apparatus.

Hereinafter, the operation of the thin film type optical path control device according to the present embodiment.

In the thin film type optical path control apparatus according to the present exemplary embodiment, a first signal is applied to the lower electrode 145 through a transistor, a drain pad of the first metal layer 105, and a via contact 165. On the other hand, since the same second signal is applied to the upper electrode 155 for each upper electrode of each actuator from the outside, an electric field is generated according to the potential difference between the upper electrode 155 and the lower electrode 145. Due to this electric field, the deformation layer 150 formed between the upper electrode 155 and the lower electrode 145 causes deformation. The strained layer 150 contracts in a direction orthogonal to the generated electric field. The lower portion of the strained layer 150 is contracted by the support layer 140, and one side thereof is structurally fixed to the active matrix 100, resulting in the strained layer 150. Actuator 170 including a bent upward with a predetermined angle. In this case, the driving angle of the actuator can be adjusted by adjusting the length of the spring bar 135. That is, since the spring bar 135 has a shorter length and a wider width, the restoring force is increased, thereby reducing the driving angle of the actuator 170. On the contrary, the longer the length of the spring bar 135 and the narrower the narrower the restoring force, the more the driving angle of the actuator 170 can be increased. The upper electrode 155, which also serves to reflect light incident from the light source, is inclined together with the actuator 170. Accordingly, the upper electrode 155 reflects the light incident from the light source at a predetermined angle, and the reflected light passes through the slit to form an image on the screen.

In this invention mentioned above, the spring bar which the one side contact | connects is formed in the both sides of an actuator. Therefore, the actuator is not only supported on one side by the actuator support, but also supported by the spring bar, so that the actuator is substantially supported in four parts. Therefore, initial tilting of the actuator can be prevented, and the actuator can be formed horizontally and stably. Furthermore, after the image signal is applied and the actuator is driven, the restoring force of the spring bar is returned to the driving angle close to the initial driving angle before receiving the next image signal. Therefore, the reproducibility of the drive angle of the actuator can be improved.

Moreover, the driving angle of the actuator can be controlled by adjusting the length and width of the spring bar.

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 (6)

An active matrix (100) containing M × N (M, N is an integer) transistors and including a first metal layer 105 including a drain pad extending from a drain of the transistor; Iii) a support layer 140 formed on the first metal layer 105 and the active matrix 100, ii) a lower electrode 145 formed on the support layer, and iv) a strained layer formed on the lower electrode. (150), and iii) an actuator (170) comprising an upper electrode (155) formed on the deformation layer; And One side is in contact with both sides of the actuator 170, the other side is supported by the spring bar support portion 137 formed in a portion corresponding to the actuator support portion 131 is a spring bar 135 formed in parallel with the actuator 170 Thin film type optical path control device comprising a). The apparatus of claim 1, wherein the support layer (140), the spring bar (135) and the spring bar support (137) are formed using the same material. The thin film type optical path control device of claim 1, wherein the spring bar 135 has a rod shape in which one side is bent in a '-' shape to be in contact with both sides of the support layer 140 and integrally formed with the support layer. . The apparatus of claim 1, wherein the actuator support (131) and the spring bar support (137) have the same height. Providing an active matrix comprising M × N (M, N is an integer) transistors, the first metal layer comprising a drain pad extending from a drain of the transistor; Forming a sacrificial layer over the first metal layer and over the active matrix; Patterning the sacrificial layer to expose both sides of the portion where the drain pad is formed in the active matrix in the shape of a rectangle, and exposing portions corresponding to the portion where the drain pad is formed in the shape of a rectangle; Forming an actuator support and a spring bar support on top of the exposed sacrificial layer; Sequentially forming a first layer, a lower electrode layer, a second layer, and an upper electrode layer on the actuator support, the spring bar support, and the sacrificial layer; And Patterning the upper electrode layer to form an upper electrode, patterning the second layer to form a strained layer, patterning the lower electrode layer to form a lower electrode, and patterning the first layer to support a layer; A method of manufacturing a thin film type optical path control device comprising the step of forming an actuator comprising the step of forming a spring bar. The method of claim 5, wherein the forming of the actuator support and the spring bar support and the forming of the first layer are performed at the same time.

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