KR100251100B1 - Thin film actuated mirror array and manufacturing method of the same - Google Patents

Abstract

PURPOSE: A thin film type apparatus for controlling a light path preventing initial inclining of an actuator and a method for manufacturing the same are provided to minimize initial inclining of an actuator and improve a contrast of an image by forming a secondary supporting member between an active matrix and a supporting layer. CONSTITUTION: An active matrix comprises the first metal layer(105) extended from a drain and a source of a MOS transistor and formed on the active matrix(100), the first protective layer(110) formed on the first metal layer(105), the second metal layer(115) formed on the first protective layer(110), the second protective layer(120) formed on the second metal layer(115) and an etching preventing layer(125) formed on the second protective layer(120). An actuator(170) involves a lower electrode(145) formed in parallel with a lower part of the active matrix(100), a strain layer(150) laminated on the lower electrode(145), and an upper electrode(155) laminated on the strain layer(150). The actuator also comprises a via hole(160) formed from the strain layer(150) to a drain pad of the first metal layer(105) vertically and a via contact formed inside the via hole(160). A supporting component(141) comprises a supporting layer(140), a supporting member(131) supporting the actuator(170) and a secondary supporting member(135) preventing initial inclining of the actuator(170).

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, to form an auxiliary support member between an active matrix and a support layer to uniform initial tilt of an actuator, thereby projecting onto a screen. The present invention relates to a thin film type optical path adjusting device capable of improving the contrast of an image to be produced 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. The image processing apparatus using the optical path adjusting device or the spatial light modulator typically has a direct-view image display device and a projection-type image device according to a method of displaying optical energy on a screen. display device).

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

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

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

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

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

Accordingly, a thin film type optical path control apparatus that can be manufactured using a semiconductor manufacturing process has been developed. Such a thin film type optical path 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 preceding application, and FIG. 2 shows a cross-sectional view taken along line A-A 'of the device shown in FIG. 1 and 2, the thin film type optical path adjusting 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 one side in contact with the etch stop layer 15 having the drain pad 5 formed below and the other side formed in parallel with the lower portion of the active matrix 1 via the air gap 25. The strained layer 40 has a membrane 30 having a cross section, a lower electrode 35 formed on the membrane 30, a strained layer 40 formed on the lower electrode 35, and a stripe 45 on one side thereof. The lower electrode 35 and the drain pad in the upper electrode 45 stacked on the upper side of the upper electrode 45 and the via hole 60 formed vertically from one side of the strained layer 40 to the upper portion of the drain pad 5. And a via contact 65 formed to be connected.

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

3A to 3E show a manufacturing process diagram of the apparatus shown in FIG.

Referring to FIG. 3A, first, an M × N MOS transistor (not shown) is embedded, and a protective layer 10 is stacked on an active matrix 1 having 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.

Referring to FIG. 3B, a 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. A first signal (image 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 from the outside.

Referring to FIG. 3C, a 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. At this time, a stripe 55 is formed on one side of the upper electrode 45 to uniformly operate the upper electrode 45 to prevent diffuse reflection of light incident from the light source. The strained layer 40 and the lower electrode 35 are each patterned to have a predetermined pixel shape.

Referring to FIG. 3D, the strain 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 strain layer 40 to the drain pad. The via hole 60 is formed so that a part of (5) is 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 and the drain pad 5 embedded in the active matrix 1 from the outside of the lower electrode 35 from the outside. And a first signal may be applied through the via contact 65. Subsequently, after the membrane 30 is patterned to have a predetermined pixel shape, the sacrificial layer 20 is etched using 49% hydrogen fluoride (HF) vapor, washed and dried to provide a thin film type optical path control device. Complete 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. At the same time, a second signal is applied to the upper electrode 45 from the outside to generate an electric field 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, and thus the actuator 50 is bent in a direction opposite to the direction in which the membrane 30 is formed. Since the upper electrode 45 formed on the actuator 50 also functions as a mirror, the upper electrode 45 is inclined in a direction opposite to the direction in which the membrane 30 is formed at a predetermined angle 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. At this time, the stripe 55 formed on one side of the upper electrode 45 operates the upper electrode 45 uniformly to prevent diffuse reflection of light.

However, in the above-described thin film type optical path adjusting device, the actuator is removed after the sacrificial layer is removed due to the stress variation and the stress distribution of the thin film stacks in the single pixel and the residual stress of the thin film stacks within the single pixel. There is a significant amount of initial tilt of. When the initial tilt of the actuator occurs, the contrast of the image projected on the screen is lowered, so uniformity of the initial tilt of the actuator is required. Inclination of the actuator of the thin film type optical path control device is caused by two types of bending moments. One bending moment exists at the stepped interface formed along the width direction W of the actuator, and the other bending moment is distributed along the length direction L of the actuator. The bending moments present at the stepped interface mainly depend on the residual stresses and the nonuniformity of the stress distribution, and the bending moments distributed along the longitudinal direction of the actuator are irrelevant. In other words, the inclination due to the bending moment at the stepped interface is superior to the inclination due to the bending moment in the longitudinal direction of the actuator. 70-80% of the total tilt of the actuator is due to the bending moment at the step interface. Due to such bending moment at the stepped boundary, there is a problem that the contrast of the image projected on the screen is lowered.

There are two ways to control the initial tilt of such actuators. One is to adjust the residual stress resulting from PZT shrinkage at the stepped interface, and the other is to reinforce the structure which is less sensitive to the residual stress or to the imbalance of the stress distribution in the actuator having the container structure. Due to variations in process variables in wafers that are common in semiconductor manufacturing processes, the magnitude and variation of residual stresses cannot be controlled to an acceptable uniformity of ± 5% or less. Therefore, even if the process is best adjusted, it is inevitable to produce non-uniformity pixel by pixel in the wafer. In order to minimize and homogenize the initial tilt of the actuator, improvements in structural design as well as efforts to control process variables must be performed.

Accordingly, it is an object of the present invention to provide an auxiliary support member between the active matrix and the support layer to reduce the residual stress or unbalance of the stress distribution of the actuator, thereby making the initial tilt of the actuator uniform and reducing the contrast of the image projected on the screen. The present invention provides 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.

3A to 3C are manufacturing process diagrams of the apparatus shown in FIG. 2.

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

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

6 to 10 are manufacturing process diagrams of the apparatus shown in FIG. 5.

11 is a plan view of a thin film type optical path control device according to a second embodiment of the present invention.

FIG. 12 is a plan view illustrating a state in which a sacrificial layer is patterned during the manufacturing process of the apparatus illustrated in FIG. 11.

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

FIG. 14 is a cross-sectional view taken along line C′C ′ of the apparatus shown in FIG. 13.

15A is a cross-sectional view illustrating a state in which a sacrificial layer is patterned during the manufacturing process of the apparatus shown in FIG. 14.

15B is a plan view illustrating a state in which a sacrificial layer is patterned during the manufacturing process of the apparatus shown in FIG. 14.

15C to 15E are plan views showing still another embodiment of patterning a sacrificial layer during the manufacturing process of the apparatus shown in FIG. 14.

16 is a plan view of a thin film-type optical path control apparatus according to a fourth embodiment of the present invention.

FIG. 17 is a plan view illustrating a state in which a sacrificial layer is patterned during the manufacturing process of the apparatus illustrated in FIG. 16.

18 is a graph showing the initial tilting degree of the actuator in the thin film type optical path adjusting apparatus described in the applicant's prior application and the thin film type optical path adjusting apparatus according to the present invention.

<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: support member

135: auxiliary support member 140: support layer

141: support element 145: lower electrode

150: strained layer 155: upper electrode

160: Beer hall 165: Beer contact

170: actuator 185: air gap

In order to achieve the above object, the present invention has a drain pad having M x N (M, N is an integer) transistor for receiving the first signal from the outside and delivering the first signal and extending from the drain of the transistor. An active matrix having a first metal layer, iii) a lower electrode to which the first signal is applied, ii) an upper electrode formed corresponding to the lower electrode, and a second signal to generate an electric field, and iii) the lower electrode; An actuator including a strained layer formed between the upper electrodes and causing deformation according to the electric field, and a) a support layer attached to a lower portion of the lower electrode to support the actuator, and b) the drain pad of the active matrix. A support member formed between the formed portion and one lower portion of the support layer to support the actuator, and c) A support element integrally formed with the support member between the lower side of the support layer and the active matrix, the support element including auxiliary support means for preventing initial tilting of the actuator, the drive element being driven in accordance with the first signal and the second signal. It provides a thin film type optical path control device.

In addition, in order to achieve the above object, the present invention, the drain pad which is embedded with M × N (M, N is an integer) transistor for receiving the first signal from the outside and delivering the first signal and extending from the drain of the transistor Iii) a lower electrode to which the first signal is applied, ii) an upper electrode formed corresponding to the lower electrode and to which a second signal is applied to generate an electric field, and iii) the lower electrode. An actuator comprising a strained layer formed between an electrode and the upper electrode to cause deformation according to the electric field, and a) a support layer attached to a lower portion of the lower electrode to support the actuator, b) the drain of the active matrix. A support member formed between the pad portion and the lower portion of one side of the support layer to support the actuator, and c) a support element formed separately from said support member between said other lower portion of said support layer and said active matrix, said support element comprising auxiliary support means for preventing initial tilting of said actuator, said first signal and said second signal It provides a thin film type optical path control device to drive according to.

In addition, in order to achieve the above object, the present invention, the drain pad which is embedded with M × N (M, N is an integer) transistor for receiving the first signal from the outside and delivering the first signal and extending from the drain of the transistor Providing an active matrix having a first metal layer formed thereon, forming a sacrificial layer on top of the active matrix, patterning the sacrificial layer to expose a portion of the active matrix in which the drain pad is formed in a quadrangular shape; Exposing a portion adjacent to the portion where the drain pad is formed to have a smaller rectangular shape than the portion where the drain pad is formed, forming a support member and an auxiliary support means on the exposed active matrix; Forming a first layer on the auxiliary support means and the sacrificial layer Forming a lower electrode layer, a second layer, and an upper electrode layer on the first layer, and patterning the upper electrode layer to form an upper electrode to generate an electric field by applying a second signal to the second layer. Forming a strained layer to cause deformation according to the electric field, patterning the lower electrode layer to form a lower electrode to which the first signal is applied, and patterning the first layer to form a support layer It includes, and provides a method of manufacturing a thin film type optical path control device for driving in accordance with the first signal and the second signal.

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. At the same time, a second signal, that is, a bias signal, is applied to the upper electrode from the outside through the common electrode line. Therefore, 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, and the actuator including the strained layer actuates upward at a predetermined angle. 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.

Therefore, in the above-described thin film type optical path control device according to the present invention, by forming the auxiliary support member between the active matrix and the support layer, it is possible to minimize the generation of the bending moment at the stepped interface. Therefore, the initial tilt of the actuator can be minimized and made uniform, and the contrast of the image projected on the screen can be improved.

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

Example 1

4 is a plan view showing a thin film type optical path adjusting device according to Embodiment 1 of the present invention, and FIG. 5 is a sectional view taken along the line B′B ′ of the device.

4 and 5, the thin film type optical path adjusting apparatus according to the first embodiment of the present invention includes an active matrix 100, an actuator 170 formed on the active matrix 100, and an active matrix 100 and an actuator. And a supporting element 141 formed between 170 to support the actuator.

Referring to FIG. 5, the active matrix 100 in which M × N (M, N is an integer) MOS transistors in which a signal is applied from the outside to perform a switching operation may include a drain and a drain of the MOS transistor. The first metal layer 105 formed on the active matrix 100, the first passivation layer 110 formed on the first metal layer 105, and the first passivation layer 110 extending from the source. The second metal layer 115 formed on the upper portion, the second protective layer 120 formed on the second metal layer 115, and the etch stop layer 125 formed on the second protective layer 120 are 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 is stacked on the lower electrode 145 and the lower electrode 145 formed in parallel with the lower portion of the active matrix 100 via an air gap 185 between the upper and lower portions of the active matrix. The strained layer 150 and the upper electrode 155 stacked on the strained layer 150 are included. In addition, the actuator 170 may include a via hole 160 formed vertically from one side of the deforming layer 150 to a drain pad of the first metal layer 105, and a via contact 165 formed inside the via hole 160. ). The lower electrode 145 is electrically connected to the drain pad of the first metal layer 105 through the via contact 165.

The supporting element 141 may include a supporting layer 140 attached to the lower portion of the lower electrode 145, a portion of the etch stop layer 125 in which a drain pad of the first metal layer 105 is formed, and the supporting layer 140. A support member 131 is formed between one lower portion of the 140 to support the actuator 170, and the support member between the lower portion of the support layer 140 and the active matrix 100. 131 is formed integrally with a secondary supporting member (135) to prevent the initial tilt of the actuator (170). Preferably, the auxiliary support member 135 has a column shape whose width is narrower than that of the support member 131 of the actuator 170.

In addition, referring to FIG. 4, one side of the support layer 140 has a concave portion having a rectangular shape in the center thereof, and the concave portion is formed in a shape that is stepped toward both edges. In addition, the other side of the support layer 140 has a quadrangular protrusion that narrows stepwise toward the central portion 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. Support members 131 of the actuator 170 having a quadrangular shape are formed under both sides of the support layer 140. The support layer 140 performs a function of a membrane supporting an actuator of the thin film type optical path adjusting device described in the previous application.

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

6 to 10 are manufacturing process diagrams of the thin film type optical path control apparatus according to the first embodiment of the present invention. 6 to 10, the same reference numerals are used for the same members as in FIG.

Referring to FIG. 6, after forming a first metal layer 105 on an active matrix 100 having M × N MOS transistors therein, the first metal layer 105 is patterned to form a MOS below it. The gate portion of the transistor is exposed. 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 made of tungsten, titanium, titanium nitride, or the like, and includes a drain pad extending from the drain region of the transistor to the support portion 131 of the actuator 170 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 Phospor-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. Subsequently, it is completed by forming a titanium nitride layer using titanium nitride (TiN) on the titanium layer. The titanium nitride layer is formed to have a thickness of about 1000 to 1200 GPa using a physical vapor deposition (PVD) method. 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 by using the silicate glass PSG. 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 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 upper portion of the active matrix 100 in which the transistor and the drain pad 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.

FIG. 7A is a cross-sectional view illustrating a state in which the sacrificial layer 130 is patterned to form a position where the supporting member 131 and the auxiliary supporting member 135 of the actuator are to be formed. 7B is a plan view illustrating a state in which the sacrificial layer is patterned.

7A to 7B, a portion of the sacrificial layer 130 on which the drain pad of the first metal layer 105 is formed is patterned in a quadrangular shape to expose a portion of the etch stop layer 125. That is, as shown in FIG. 7B, the sacrificial layer 130 is patterned into a rectangular shape having a length L ₁ and a width W ₁ to form the support member 131 of the actuator 170. Make the part to be At the same time, the sacrificial layer 130 is patterned from a side of one side of the support member 131 into a quadrangular shape having a narrower width than the support member 131 to expose a portion of the etch stop layer 125. That is, as shown in FIG. 7B, the sacrificial layer 130 is patterned and supported in a rectangular shape having a length L ₂ and a width W ₂ from one side of the support member 131. The portion where the support member 135 is to be formed is made. The cross-sectional area of the portion where the support member 131 is to be formed is larger than the cross-sectional area of the portion where the auxiliary support member 135 is to be formed. Preferably, the sacrificial layer 130 has a ratio (W ₁ : W ₂ ) of the width of the supporting member 131 and the auxiliary supporting member 135 of from 8: 1 to 4: 1, and the ratio of the length of the sacrificial layer 130. The patterning is performed so that (L ₁ : L ₂ ) is 2: 1 to 1: 1. More preferably, the sacrificial layer 130 has a ratio (W ₁ : W ₂ ) of the width of the supporting member 131 and the auxiliary supporting member 135 to 8: 1, and the ratio of the length (L _1). : L ₂ ) is patterned to be 1: 1. For example, when the portion of the sacrificial layer 130 on which the support member 131 of the actuator 170 is to be formed is patterned into a rectangular shape having a width of 16 μm and a length of 10 μm, the auxiliary support member 135 is formed. The part to be patterned is a rectangular shape having a length of 10 m and a width of 2 m. Therefore, one surface of the auxiliary support member 135 formed later comes into contact with one surface of the support member 131 and is integrally formed with the support member 131.

Conventionally, due to the thickness variation in the processed wafers and the unbalance of residual stresses and stress distributions of thin film stacks within a single pixel, there was a significant amount of initial tilt of the actuator at the stepped interface after removing the sacrificial layer. When the initial tilt of the actuator occurs due to the bending moment at the stepped boundary surface (the width direction of the actuator), there is a problem that the contrast of the image projected on the screen is lowered.

Therefore, in the present embodiment, the above-mentioned problems are solved by reinforcing the actuator to a structure that is less sensitive to an imbalance of residual stress or stress distribution. That is, since the bending moment at the stepped boundary is proportional to the width of the stepped boundary, when the auxiliary support member 135 having a narrow width is formed on one side of the support member 131, the bending moment is Since it occurs to a degree proportional to the width of the auxiliary support member 135, the initial degree of inclination of the actuator 170 is significantly reduced. That is, as illustrated above, when the length of the width of the supporting member 131 is 16 μm and the length of the width of the auxiliary supporting member 135 is 2 μm, the bending moment is provided with the auxiliary supporting member. It is reduced by about compared to the case where it is not. Therefore, the actuator 170 can be remarkably reduced in inclined upwardly in a state in which the first signal is not applied.

In this embodiment, although the supporting member 131 and the auxiliary supporting member 135 having the above ratios of width and length are formed, the present embodiment is not limited thereto but as shown in FIG. 7C. The ratio (W ₁ : W ₂ ) of the width of the 131 and the auxiliary support member 135 may be 8: 1, and the ratio L ₁ : L ₂ of the length may be 2: 1.

Referring to FIG. 8, the first layer 139 is stacked using a rigid material such as 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 support member 131 and the auxiliary support member 135 of the actuator 170. Accordingly, the support member 131 and the auxiliary support member 135 of the actuator 170 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. In addition, the second layer 149 may be formed using an electrostrictive material such as PMN. 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. In the above, when the second layer 149 is formed using ZnO, the second layer 149 may be formed at a low temperature of 300 ° C to 600 ° C. Therefore, the active matrix 100 can be prevented from being damaged by heat. In addition, when the second layer 149 is formed using ZnO, since the polarization is performed by an applied electric field, a separate polarization step 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. 9, 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. Form. Subsequently, the photoresist is 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.

Subsequently, 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. The hole 160 is formed. 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 using a sputtering method to form a via contact 165, and then patterning the via contact 165. 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.

A first signal, that is, an image signal, is applied to the lower electrode 145 through the transistor, the drain pad formed in the active matrix 100, and the via contact 165 formed in a subsequent process. Therefore, when the first signal is applied to the lower electrode 145 and the second signal is applied to the upper electrode 155 at the same time, 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. 10, the sacrificial layer 130 is removed using hydrogen fluoride (HF) vapor. When the sacrificial layer 130 is removed, the air gap 185 is formed at the position of the sacrificial layer 130 to complete the actuator 170.

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

In the thin film type optical path adjusting device according to the present exemplary embodiment, a first signal, that is, an image 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. At the same time, a second signal, that is, a bias signal, is applied to the upper electrode 155 through the common electrode line. Thus, an electric field is generated 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 perpendicular to the generated electric field. Accordingly, the actuator 170 including the deformation layer 150 is actuated upward at a predetermined angle. The upper electrode 155, which also serves to reflect light incident from the light source, is inclined together with the actuator 200. 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.

As a result of measuring the initial tilt degree of the thin film type optical path adjusting device according to the present embodiment, using an interferometer and a laser measuring method. An initial tilt value of about 90 μm was obtained.

Example 2

FIG. 11 is a plan view of a thin film type optical path adjusting device according to Embodiment 2, and FIG. 12 is a plan view showing a state in which the sacrificial layer 130 is patterned during the manufacturing process of the device shown in FIG. The plan view and cross-sectional view of the thin film type optical path control device according to the second embodiment of the present invention is the device according to the first embodiment shown in Figs. 4 and 5, except for two auxiliary support members 235 and its configuration and shape same. In the present embodiment, the same reference numerals are used for the same members as in the first embodiment.

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

In the present embodiment, the process from forming the sacrificial layer 130 to planarizing the same is the same as the first embodiment of the present invention shown in FIG. 6.

12, the support member of the actuator 170 having the same size as that of the first embodiment is patterned by patterning a portion of the sacrificial layer 130 where the drain pad of the first metal layer 105 is formed in a square shape. 131 makes a position to be formed. At the same time, the sacrificial layer 130 is patterned to form a position where the auxiliary supporting members 235 are to be formed. That is, the position at which the auxiliary support members 235 are to be formed is formed in a quadrangular shape having the same size as in the first embodiment from the stepped boundary surface of the support member 131. Therefore, one surface of each of the auxiliary support members 235 formed in a subsequent process may be in contact with one surface of the support member 131 and may be integrally formed with the support member 131. The two parts where the auxiliary supporting members 235 are to be formed are formed side by side apart from each other at a predetermined interval.

Preferably, the sacrificial layer 130 has a ratio (W ₁ : W ₂ ) of the width of each of the supporting member 131 and the auxiliary supporting members 235 is 8: 1, and the ratio L of the length of the sacrificial layer 130. ₁ : L ₂ ) is patterned to be 1: 1. For example, when the portion of the sacrificial layer 130 on which the support member 131 of the actuator 170 is to be formed is patterned into a rectangular shape having a width of 16 μm and a length of 10 μm, the auxiliary support members 235 may be formed. The portions to be formed are patterned in a rectangular shape having a length of 10 μm and a width of 2 μm.

In the present embodiment, the subsequent manufacturing process is the same as the first embodiment of the present invention shown in Figs. 8 to 10, and the operation of the apparatus according to the present embodiment is also the same as the first embodiment.

As a result of measuring the initial tilt degree of the thin film type optical path adjusting device according to the present embodiment using an interferometer and a laser measuring method. An initial tilt value of about 15 μm was obtained.

Example 3

FIG. 13 is a plan view of a thin film type optical path adjusting device according to a third embodiment of the present invention, and FIG. 14 is a cross-sectional view taken along line C′C ′ of the device shown in FIG. 13.

4 and 5 are plan views and cross-sectional views of the thin film optical path control apparatus according to the third exemplary embodiment of the present invention, except that the auxiliary support member 335 is separated from the support member 131 by a predetermined interval. The device and its configuration and shape are the same according to the first embodiment. In the present embodiment, the same reference numerals are used for the same members as in the first embodiment.

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

In the present embodiment, the process from forming the sacrificial layer 130 to planarizing the same is the same as the first embodiment of the present invention shown in FIG. 6. FIG. 15A is a cross-sectional view illustrating a state in which the sacrificial layer 130 is patterned during the manufacturing process of the apparatus illustrated in FIG. 14, and FIG. 15B is a pattern illustrating the sacrificial layer 130 during the manufacturing process of the apparatus illustrated in FIG. 14. It is a top view which shows a state.

15A and 15B, a portion of the sacrificial layer 130 having the drain pad of the first metal layer 105 formed thereon is patterned in a quadrangular shape to form an actuator 170 having the same size as that of the first embodiment. The portion where the support member 131 is to be formed is made. At the same time, the auxiliary supporting member 335 exposes a portion of the etch stop layer 125 by patterning a portion of the sacrificial layer 130 spaced apart from the supporting member 131 of the actuator 170 by a square shape. Make the part to be formed.

Preferably, the sacrificial layer 130 has a ratio (W ₁ : W ₂ ) between the widths of the support member 131 and the auxiliary support member 335 of 8: 1-4: 1, (L _1: L ₂₎ is 5: is patterned such that the 1: 1 to 2. More preferably, the sacrificial layer 130 has a ratio (W ₁ : W ₂ ) of the width of the support member 131 and the auxiliary support member 335 is 16: 3, and the ratio of the length (L _1). : L ₂ ) is patterned to be 10: 3. For example, when the portion of the sacrificial layer 130 on which the support member 131 of the actuator 170 is to be formed is patterned into a rectangular shape having a width of 16 μm and a length of 10 μm, the auxiliary support member 335 is formed. The part to be patterned is a square shape having a length of 3 m and a width of 3 m. Therefore, the auxiliary support member 335 formed in the subsequent process is formed in the shape of a square pillar at a position away from the support member 131 of the actuator 170 by a predetermined distance.

In the present embodiment, the supporting member 131 and the auxiliary supporting member 335 having the above ratios of width and length are formed, but the present embodiment is not limited thereto and is shown in FIGS. 15C to 15E. Similarly, the ratio (W ₁ : W ₂ ) of the width of the supporting member 131 and the auxiliary supporting member 135 is 8: 1 or 4: 1, and the ratio (L ₁ : L ₂ ) of the length is 5: 1, You may form so that it may become 5: 2 or 2: 1.

In the present embodiment, the subsequent manufacturing process is the same as the first embodiment of the present invention shown in Figs. 8 to 10, and the operation of the apparatus according to the present embodiment is also the same as the first embodiment.

As a result of measuring the initial tilt degree of the thin film type optical path adjusting device according to the present embodiment using an interferometer and a laser measuring method. 4. 30 to 5. An initial tilt value of about 05 μm was obtained.

Example 4

FIG. 16 is a plan view showing a thin film type optical path adjusting device according to Embodiment 4 of the present invention, and FIG. 17 is a plan view showing a state in which the sacrificial layer 130 is patterned during the manufacturing process of the device shown in FIG. 16. A plan view and a cross-sectional view of the thin film type optical path adjusting device according to the fourth embodiment of the present invention are except that two auxiliary supporting members 435 are formed at a predetermined distance from the supporting member 131 of the actuator 170. The configuration and shape of the apparatus according to the third embodiment shown in FIG. 13 and FIG. 14 are the same. In the present embodiment, the same reference numerals are used for the same members as in the first embodiment.

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

In the present embodiment, the process from forming the sacrificial layer 130 to planarizing the same is the same as the first embodiment of the present invention shown in FIG. 6.

Referring to FIG. 17, a portion of the sacrificial layer 130 having the drain pad of the first metal layer 105 formed thereon is patterned in a square shape to support the actuator 170 having the same size as that of the first embodiment. 131 makes a position to be formed. At the same time, the auxiliary supporting members may be formed by patterning portions of the sacrificial layer 130 spaced apart from the supporting member 131 of the actuator 170 in two rectangular shapes to expose a portion of the etch stop layer 125. 435 makes a part to be formed. Therefore, the auxiliary supporting members 435 formed in a subsequent process are formed in the shape of a square pillar at a position away from the supporting member 131 of the actuator 170 by a predetermined distance. The two portions on which the auxiliary supporting members 435 are to be formed are separated from each other at predetermined intervals and are formed side by side.

Preferably, the sacrificial layer 130 has a ratio (W ₁ : W ₂ ) of the width of the supporting member 131 and the auxiliary supporting members 435 is 8: 1, and the ratio of the length (L _1). : L ₂ ) is patterned to be 5: 1. For example, when the portion of the sacrificial layer 130 on which the support member 131 of the actuator 170 is to be formed is patterned into a rectangular shape having a width of 16 μm and a length of 10 μm, the auxiliary support members 435 may be formed. The portion to be formed is patterned in a square shape having a length of 2 m and a width of 2 m.

In the present embodiment, the subsequent manufacturing process is the same as the first embodiment of the present invention shown in Figs. 8 to 10, and the operation of the apparatus according to the present embodiment is also the same as the first embodiment.

As a result of measuring the initial tilt degree of the thin film type optical path adjusting device according to the present embodiment using an interferometer and a laser measuring method. An initial tilt value of about 20 μm was obtained.

18 is a graph showing the initial tilting degree of the actuator in the thin film type optical path adjusting apparatus described in the applicant's prior application and the thin film type optical path adjusting apparatus according to the present invention. The thin film type optical path adjusting device described in the applicant's prior application in which the auxiliary supporting member was not formed is shown as a comparative example. The initial tilt degree of the thin film type optical path control apparatus according to each embodiment of the present invention was measured using an interferometer and a laser measuring method. The initial tilt value of the thin film type optical path adjusting device (comparative example) described in the preceding application in which the auxiliary supporting member is not formed is 6. 0-7. It was about 4 micrometers.

Referring to FIG. 18, it can be seen that the absolute value and the deviation of the initial tilt value of the actuator of the thin film type optical path adjusting device manufactured according to the embodiments of the present invention are very small when compared with the results of the comparative example. Accordingly, it can be seen that forming the auxiliary support member between the active matrix and the support layer can reduce the residual stress or the unbalance of the stress distribution of the actuator, and thus is very effective in reducing the initial tilting degree of the actuator.

In addition, in the case where one auxiliary supporting member is formed (Examples 1 and 3), while the deviation and absolute value of the initial inclination value of the actuator 170 are relatively small, good results are obtained, while two auxiliary supporting members are provided. In the case of forming (Example 2 and Example 4), the absolute value of the initial tilt value of the actuator 170 is small, but the deviation is large. Therefore, it can be seen that one auxiliary supporting member is more preferable than two auxiliary supporting members.

In Examples 1 to 4 of the present invention described above, by forming the auxiliary support member between the active matrix and the support layer, it is possible to minimize the generation of the bending moment at the stepped interface. Therefore, the initial tilt of the actuator can be minimized and made uniform, and the contrast of the image projected on the screen can be improved.

When applying the same method as Examples 1 to 4 according to the present invention, by forming one side of the auxiliary support member in a sharp shape, it is possible to significantly reduce the bending moment generated in proportion to the width of the auxiliary support member. Therefore, it will be appreciated that the thin film type optical path control device can be manufactured in which the absolute value and the deviation of the initial tilt value of the actuator are greatly reduced.

Furthermore, the auxiliary supporting member can be formed at the same time as the supporting member when the sacrificial layer is patterned by modifying only the mask used when patterning the sacrificial layer, so that the auxiliary supporting member can be easily formed without a process change that is difficult to control.

The present invention has been described and illustrated in detail by the preferred embodiments, but the present invention is not limited thereto, and it is possible for a person skilled in the art to modify or improve the present invention within a conventional range. .

Claims (13)

An active matrix having a first metal layer 105 having M x N (M, N is an integer) transistors receiving the first signal from the outside and delivering the first signal and having drain pads extending from the drain of the transistor 100; Iii) a lower electrode 145 to which the first signal is applied, ii) an upper electrode 155 formed corresponding to the lower electrode and generating a electric field by applying a second signal, and iii) the lower electrode and the upper part. An actuator (170) formed between the electrodes and including a deformation layer (150) for causing deformation according to the electric field; And a) a supporting layer 140 attached to a lower portion of the lower electrode 145 to support the actuator 170, b) a portion of the active matrix 100 in which the drain pad is formed and the supporting layer 140 A support member 131 formed between one lower portion of the one side and supporting the actuator 170, and c) between the lower side of the other side of the supporting layer 140 and the active matrix 100. A support element 141 formed integrally with 131 and including secondary supporting means 135 to prevent initial tilting of the actuator 170, the first signal and the second signal. Thin film type optical path control device to drive according to. The apparatus of claim 1, wherein the support layer (140), the support member (131) and the auxiliary support means (135) are formed using the same material. The apparatus of claim 1, wherein an area of the support member (131) is larger than an area of the auxiliary support means (135). The apparatus of claim 3, wherein the support member 131 has a rectangular cross section, and the auxiliary support means 135 has a rectangular cross section smaller than the support member 131. . The auxiliary supporting means 135 has a width ratio of 8: 1 to 4: 1, and a length ratio of 2: 1 to 1: 1 compared to the supporting member 131. Thin film type optical path control device. The thin film type optical path control apparatus according to claim 1, wherein two auxiliary support means (235) are formed in parallel with the support member on one side of the support member (131). The apparatus of claim 1, wherein the apparatus further comprises reflecting means on an upper portion of the upper electrode (155). An active matrix having a first metal layer 105 having M x N (M, N is an integer) transistors receiving the first signal from the outside and delivering the first signal and having drain pads extending from the drain of the transistor 100; Iii) a lower electrode 145 to which the first signal is applied, ii) an upper electrode 155 formed corresponding to the lower electrode and generating a electric field by applying a second signal, and iii) the lower electrode and the upper part. An actuator (170) formed between the electrodes and including a deformation layer (150) for causing deformation according to the electric field; And a) a support layer 140 attached to a lower portion of the lower electrode 145 to support the actuator 170, b) a portion in which the drain pad is formed in the active matrix 100 and a lower portion of one side of the support layer 140 A support member 131 formed therebetween to support the actuator 170, and c) formed separately from the support member 131 between the lower side of the support layer 140 and the active matrix 100. And a support element (141) comprising an auxiliary support means (335) for preventing initial tilting of the actuator (170), the thin film type optical path control device being driven in accordance with the first signal and the second signal. The method of claim 8, wherein the support member 131 has a cross section of a rectangular shape, the auxiliary support means 335 has a cross section of a smaller rectangular shape than the support member, the auxiliary support means 335 is the support The ratio of the width | variety is 8: 1-4: 1 compared with a member, and the ratio of the length is 5: 1-2: 1. The thin film type optical path control device according to claim 8, wherein two auxiliary support means (435) are formed to be parallel to each other, separated from the support member (131). Providing an active matrix having a first metal layer having M x N (M, N is an integer) transistors receiving the first signal from the outside and delivering the first signal and having drain pads extending from the drain of the transistor. step; Forming a sacrificial layer on top of the active matrix; Patterning the sacrificial layer to expose a portion where the drain pad is formed in the active matrix in a quadrangle shape, and expose a portion adjacent to the portion where the drain pad is formed in a quadrangle shape smaller than a portion where the drain pad is formed; Forming a support member and auxiliary support means on top of the exposed active matrix; Forming a first layer on the support member, the auxiliary support means, and the sacrificial layer; Forming a lower electrode layer, a second layer, and an upper electrode layer on the first layer; Patterning the upper electrode layer to form an upper electrode to which a second signal is applied to generate an electric field; Patterning the second layer to form a strained layer that causes strain in accordance with the electric field; Patterning the lower electrode layer to form a lower electrode to which the first signal is applied; And And forming a support layer by patterning the first layer, wherein the first layer is driven according to the first signal and the second signal. The method of claim 11, wherein the forming of the supporting member, the auxiliary supporting means, and the forming of the first layer are performed simultaneously. 12. The method of claim 11, wherein the method further comprises forming reflecting means on the upper electrode.

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