KR20000032304A - Fabrication method of thin film actuated mirror array - Google Patents

Abstract

PURPOSE: A fabrication method of thin film actuated mirror array is provided to protect an actuator formed on a front surface of an actuator in etching process for patterning a rear surface of an active matrix. CONSTITUTION: A fabrication method of thin film actuated mirror array comprises steps of: forming an actuator(210) on an active matrix(100); forming support elements(175) between the active matrix and the actuator; patterning the rear surface of the active matrix; and forming a mirror(260). The actuator and the support elements are formed by forming a first layer, a lower electrode layer, a second layer and an upper electrode layer on the active matrix and then sequentially patterning them. The actuator comprises first/second upper electrodes, first/second deformation layers and a lower electrode. The support elements comprise a support layer, support lines and first/second anchors.

Description

Manufacturing method of thin film type optical path control device

The present invention relates to a method for manufacturing a thin film type optical path control apparatus using thin-film micromirror array-actuated (TMA), and more particularly, is formed on the front surface of an active matrix during an etching process for patterning a backside of an active matrix. It relates to a method for manufacturing a thin film type optical path control device that can protect the actuator.

Optical path control devices or spatial light modulators for projecting optical energy onto the screen can be applied to various fields such as optical communication, image processing and information display devices. Typically, image processing apparatuses using such an optical modulator are classified into a direct view type image display device and a projection type image display device according to a method of displaying optical energy on a screen.

An example of a direct view image display device is a CRT (Cathode Ray Tube), which is a so-called CRT device, which has excellent image quality but increases in weight and volume as the size of the screen increases, leading to increased manufacturing costs. There is. Examples of the projection image display apparatus include a liquid crystal display (LCD), a deformable mirror device (DMD), and an actuated mirror array (AMA). Such projection image display apparatuses can be further divided into two groups according to their optical characteristics. That is, devices such as LCDs can be classified as transmit light modulators, while DMD and AMA can be classified as reflected 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, the light efficiency is low due to the polarity of the light, there is a problem inherent in the liquid crystal material, for example, the response speed is slow and its inside is easy to overheat. In addition, the maximum light efficiency of existing transmission optical modulators is limited to a range of 1-2% and requires 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. AMA reflects the light incident from the light source at a predetermined angle, and each mirror installed therein adjusts the luminous flux so that the reflected light is projected on the screen through an opening such as a slit or pinhole to form an image. Device. 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 brighter and clearer image.

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

Accordingly, a thin film type optical path control device (TMA) 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. 98-41672 (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 October 2, 1998.

Figure 1 shows a perspective view of the thin film type optical path control device described in the preceding application, Figure 2 shows a cross-sectional view of the device of Figure 1 cut along the line A ₁ -A ₂ .

1 and 2, the thin film type optical path control device includes an active matrix 1, a support element 75, an actuator 90, and a mirror 99.

The active matrix 1 in which M x N (M, N are integers) containing MOS transistors (not shown) includes a drain pad 5, an active matrix 1, and a drain pad 5 extending from the drain of the transistor. Protection layer 35 stacked on top of the substrate) and an etch stop layer 40 stacked on top of the protective layer 35.

The support element 75 includes a support line 74 formed on the top of the active matrix 1, a support layer 73 of a square ring formed integrally with the support line 74, and a support line 74 of the support layers 73. The first anchor 71 and the second anchors 72a and 72b are respectively in contact with the active matrix 1 below the portion adjacent to each other and support the support layer 73.

The actuator 90 is formed on the support layer 73 in the shape of a mirror-shaped 'c' with respect to the support line 74, the lower electrode 80, the first strained layer 82, the second strained layer ( 83), a first upper electrode 85, and a second upper electrode 86. The lower electrode 80 has a mirror-shaped 'c' shape spaced apart from the support line 74 by a predetermined distance, and protruding portions are stepped toward the first anchor 71 at one side of the lower electrode 80. Are formed corresponding to each other. The protrusions of the lower electrode 80 extend to the periphery of the via hole 50 formed in the first anchor 71, respectively. The mirror 99 and the hard mask 92 at the bottom thereof are supported at the center by the post 98, and both sides thereof are formed horizontally on the actuator 90 via the second air gap 97.

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 3D are diagrams for describing a method of manufacturing the apparatus shown in FIGS. 1 and 2. Referring to FIG. 3A, a protective layer is formed on top of an active matrix 1 in which M x N (M, N is an integer) MOS transistors (not shown) are formed and a drain pad 5 extending from the drain of the transistor is formed. 35 is formed. The protective layer 35 is formed to have a thickness of 0.1 to 1.0 μm by chemical vapor deposition (CVD). The protective layer 35 is made of silicate glass (PSG) and prevents damage to the active matrix 1 in which the MOS transistor and the drain pad 5 are formed during the subsequent process.

An etch stop layer 40 is formed on the passivation layer 35 to prevent the passivation layer 35 and the active matrix 1 from being etched during the subsequent etching process. The etch stop layer 40 is formed by depositing nitride by low pressure chemical vapor deposition (LPCVD).

The first sacrificial layer 45, which serves to facilitate the stacking of the thin films constituting the actuator 90, is stacked on the etch stop layer 40. The first sacrificial layer 45 is formed to have a thickness of 2.0-3.0 μm by depositing polysilicon at a temperature of 500 ° C. or less by low pressure chemical vapor deposition. Subsequently, the surface of the first sacrificial layer 45 is polished using a chemical mechanical polishing (CMP) method to planarize the surface of the first sacrificial layer 45 to have a thickness of 1.1 μm. Subsequently, after applying and patterning a first photoresist (not shown) on top of the first sacrificial layer 45, the drain pad 5 is disposed below the first sacrificial layer 45 by using the pattern as a mask. By etching the located portion and the portions adjacent to both sides to expose a portion of the anti-etching layer 40, a position where the first anchor 71 and the second anchors 72a and 72b are to be formed later is formed and the first photoresist is removed. Remove Accordingly, the etch stop layer 40 is exposed in the shape of three squares spaced apart by a predetermined distance.

The first layer 69 is stacked above the exposed etch stop layer 40 and the first sacrificial layer 45. The first layer 69 is formed to have a thickness of 0.1 to 1.0 μm of a hard material such as nitride or metal by low pressure chemical vapor deposition (LPCVD). The lower electrode layer 79 is stacked on top of the first layer 69. The lower electrode layer 79 is formed to have a thickness of 0.1 to 1.0 μm by depositing a metal such as platinum (Pt), tantalum (Ta), or platinum-tantalum (Pt-Ta) by sputtering or chemical vapor deposition.

A second layer 59 made of a piezoelectric material such as PZT or PLZT is stacked on the lower electrode 79. Preferably, the second layer 59 is formed to have a thickness of 0.4 μm by sputtering PZT produced by the sol-gel method. Subsequently, the piezoelectric material constituting the second layer 59 is subjected to heat treatment by rapid thermal treatment (RTA) to cause phase shift. The upper electrode layer 87 is stacked on top of the second layer 59. The upper electrode layer 87 is formed to have a thickness of 0.1 to 1.0 μm by depositing a metal such as platinum, tantalum, silver (Ag), or platinum-tantalum by a sputtering method or a chemical vapor deposition method.

Referring to FIG. 3B, after applying and patterning a second photoresist (not shown) on the upper electrode layer 87, the upper electrode layer 87 has a rectangular flat shape using each of the upper electrode layers 87 as a mask. The first and second upper electrodes 85 and 86 are spaced apart by a predetermined distance (see FIG. 1). A second signal (bias signal) is applied to the first and second upper electrodes 85 and 86 through a common electrode line 77 formed later from the outside, respectively. Then, the second photoresist is removed.

Subsequently, the second layer 59 is patterned in the same manner as the patterning of the upper electrode 87 to form a rectangular flat plate, and the first and second strained layers 82 and 83 spaced apart from each other by a predetermined distance. ). In this case, as shown in FIG. 1, the first and second strained layers 82 and 83 are patterned to have a slightly larger area than the first and second upper electrodes 85 and 86, respectively. Subsequently, the lower electrode layer 79 is patterned in the same manner as the method of patterning the upper electrode 87 to have a mirror-shaped 'c' shape for the support line 74 formed later, and the first anchor 71 is formed. To form a lower electrode 80 having protrusions formed in a stepped toward. In this case, the two arms of the lower electrode 80 have the shape of a rectangular flat plate having a larger area than the first and second deforming layers 82 and 83, respectively.

In addition, when the lower electrode layer 79 is patterned, the common electrode line 77 is simultaneously formed in a direction perpendicular to the lower electrode 80 on one side of the first layer 69. The common electrode line 77 is formed to be spaced apart from the lower electrode 80 by a predetermined distance on the support line 74 formed later.

Subsequently, the first layer 69 is patterned to form a support element 75 comprising a support layer 73, a support line 74, a first anchor 71 and second anchors 72a, 72b. . At this time, both sides of the portion of the first layer 69 which contacts the etch stop layer 40 exposed in the shape of the three quadrangles are second anchors 72a and 72b, and the center portion of the first anchor 69 is the first anchor 71. ) The first anchor 71 and the second anchors 72a and 72b each have a rectangular box shape, and a drain pad 5 is positioned below the first anchor 71.

The first and second deformable layers 82 and 83 are formed parallel to each other on two arms horizontally extending in a direction orthogonal to the support line 74 of the support layer 73, respectively. Accordingly, the first anchor 71 is formed between the mirror-shaped 'c' shaped lower electrodes 80, and the second anchors 72a and 72b are formed at the outer bottom of the lower electrode 80, respectively. .

Subsequently, a third photoresist (not shown) is applied and patterned on top of the support element 75 and the actuator 90 including the support layer 73 and the support line 74 to support the line 74. Portions of the first and second upper electrodes 85 and 86 are exposed from the common electrode line 77 formed thereon. At this time, even the protrusion of the lower electrode 80 is exposed together from the first anchor 71. Subsequently, the first insulating layer 65 is deposited from a portion of the first upper electrode 85 to a portion of the support layer 73 by depositing and patterning amorphous silicon or silicon oxide or phosphorus pentoxide, which is a low temperature oxide, on the exposed portion. And a second insulating layer 66 from a part of the second upper electrode 86 to a part of the support layer 73 at the same time. The first and second insulating layers 65 and 66 are formed to have a thickness of 0.2 to 0.4 탆, respectively, using low pressure chemical vapor deposition (LPCVD).

Subsequently, the first anchor 71, the etch stop layer 40, the second passivation layer 35, and the first passivation layer () are formed from the center of the first anchor 71, which is a portion where the drain pad 5 is positioned below. After etching 25 to form a via hole 50 to the drain pad 5, a via contact 89 is formed from the drain pad 5 to the protrusion of the lower electrode 80 through the via hole 50 (FIG. 1). At the same time, a first upper electrode connecting member 67 is formed from one side of the first upper electrode 85 to the common electrode line 77, and a second portion from one side of the second upper electrode 86 to the common electrode line 77. The upper electrode connecting member 68 is formed.

After the via contact 89 and the first and second upper electrode connecting members 67 and 68 are deposited to have a thickness of 0.1 to 0.2 μm by platinum, tantalum or platinum-tantalum, respectively, by sputtering or chemical vapor deposition. Then, the deposited metal is formed by patterning. The first and second upper electrode connecting members 67 and 68 connect the first and second upper electrodes 85 and 86 and the common electrode line 77, respectively, and the lower electrode 80 connects the via contact 89. It is connected to the drain pad 5 through.

Referring to FIG. 3C, after forming the photoresist protective layer 93 on the active matrix 1 having the actuator 90 and the support element 75 to a thickness of about 2 μm, the active matrix 1 may be formed. By applying and patterning a fourth photoresist 94 on the backside, the backside of the active matrix 1 is etched to a predetermined depth by using the patterned fourth photoresist 94 as a mask. A large number of irregularities are formed on the back surface of the active matrix 1. At this time, in the etching process for patterning the back surface of the active matrix 1, the photoresist protective layer 93 comes into contact with equipment by an actuator 90 formed on the front surface of the active matrix 1. Prevents this from occurring. As described above, by forming a plurality of uneven parts on the rear surface of the active matrix 1, bowing of both ends of the TMA module may be prevented after completing all manufacturing processes.

Referring to FIG. 3D, after the fourth photoresist 94 and the photoresist protective layer 93 are removed, the accucu (on the front surface of the active matrix 1, that is, the actuator 90 and the support element 75) is removed. accuflo) is used to form the second sacrificial layer 95.

Next, a hard mask 92 made of aluminum or silicon oxide (SiO ₂ ) is formed on top of the second sacrificial layer 95 to form the mirror 99 and the post 98. After the hard mask 92 is patterned by a photolithography method, the second sacrificial layer 95 is patterned along the hard mask 92 pattern to support the support line 74 of the lower '80' mirror electrode 80. A portion of the portion formed in parallel but not adjacent to (ie, a portion where the first and second upper electrodes 85 and 86 are not formed thereon) is exposed. The hard mask 92 is formed by depositing the same aluminum as the mirror 99 formed later by a sputtering method or a chemical vapor deposition method.

Subsequently, a portion of the exposed lower electrode 80 and a metal such as aluminum (Al) having high reflectivity on the upper portion of the hard mask 92 are formed to a thickness of about 0.1 to 1.0 μm using a sputtering method or a chemical vapor deposition method. The deposited metal is patterned to simultaneously form a mirror 99 having a rectangular flat plate shape and a post 98 supporting the mirror 99.

After the second sacrificial layer 95 is removed by plasma ashing, the first sacrificial layer 45 is removed by using xenon fluoride (XeF ₂ ) or bromine fluoride (BrF ₂ ), followed by cleaning. And drying treatment to complete the TMA element as shown in FIG. 1. As described above, when the second sacrificial layer 95 is removed, the second air gap 97 is formed at the position of the second sacrificial layer 95, and when the first sacrificial layer 45 is removed, the first sacrificial layer 45 is removed. The first air gap 47 is formed at the position of.

In the above-described method for manufacturing a thin film type optical path control device, a photoresist protective layer is formed to prevent the actuator formed on the front surface of the active matrix from directly contacting the equipment during the photolithography process for patterning the back surface of the active matrix. do. However, since the photoresist protective layer is not only low in hardness but also laminated at a thickness of about 2 μm, scratches easily occur when contacting the equipment, so that the actuator cannot be completely protected. In addition, since the photoresist protective layer has a low thermal stability of about 180 ° C. or less, there is a problem in that an automated process by a hot plate cannot be performed during a photographic process.

Accordingly, it is an object of the present invention to provide a method for manufacturing a thin film type optical path control apparatus that can protect an actuator formed on the front surface of an active matrix during an etching process for patterning the back surface of an active matrix.

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

FIG. 2 is a cross-sectional view of the device of FIG. 1 taken along line A ₁ -A _2. FIG.

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

Figure 4 is a perspective view of a thin film type optical path control device according to an embodiment of the present invention.

FIG. 5 is a cross-sectional view of the apparatus shown in FIG. _{4 taken along} line B ₁ -B ₂ .

6A to 6F are manufacturing process diagrams of the apparatus shown in FIG.

7 is a manufacturing process chart of a thin film type optical path control device according to another embodiment of the present invention.

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

100: active matrix 101: substrate

120: transistor 135: first metal layer

140: first protective layer 145: second metal layer

150: second protective layer 155: etch stop layer

160: first sacrificial layer 170: support layer

171: first anchor 172a, 172b: second anchor

174: support line 175: support element

180: lower electrode 190, 191: first and second strained layers

200, 201: first and second upper electrodes 210: actuators

220, 221: first and second insulating layers

230 and 231: first and second upper electrode connecting members

250: Post 260: Mirror

270: Beer Hall 280: Beer Contact

300: second sacrificial layer 310: second air gap

320: photoresist protective layer 330: first hard mask

340: fourth photoresist 350: AccuFlu protective layer

370: second hard mask

In order to achieve the above object of the present invention, the present invention comprises the steps of forming an actuator on top of an active matrix including a first metal layer having a transistor embedded therein and having a drain pad, and forming a support element between the active matrix and the actuator. It provides a method of manufacturing a thin film type optical path control device comprising the step of, patterning the back surface of the active matrix, and forming a mirror. The actuator and the supporting element are formed by sequentially forming a first layer, a lower electrode layer, a second layer and an upper electrode layer on the active matrix, and then patterning the upper and lower electrode layers sequentially. The actuator includes first and second upper electrodes, first and second strained layers, and a lower electrode, and the support element includes a support layer, a support line, and a first anchor and a second anchor. The patterning of the back surface of the active matrix may include forming a photoresist protective layer and a hard mask on the support element and the actuator, and then patterning the back surface of the active matrix by a photolithography method and removing the photoresist protective layer and the hard mask. Is performed.

In addition, the patterning of the back surface of the active matrix may be performed by forming an acuflo protective layer on the support element and the actuator, then patterning the back surface of the active matrix by a photolithography method and removing the acuflo protective layer. have.

According to the present invention, a hard mask made of a photoresist and a metal is formed on the front surface of the active matrix on which the actuator and the supporting element are formed, or an acuflo protective layer is formed, and then the back surface of the active matrix is patterned by a photolithography method. Since the metal hard mask or AccuFlu protective layer has higher hardness than photoresist, no scratch occurs even when contacted with photographic equipment or etching equipment, and thus is formed on the front surface of the active matrix during the photolithography process for patterning the back surface of the active matrix. The actuator can be safely protected from scratches and dust. In addition, since the metal hard mask or the acuflo protective layer has a higher thermal stability than the photoresist, automation by a hot plate during the photolithography process is possible.

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

Figure 4 shows a perspective view of the thin film type optical path control apparatus according to the present invention, Figure 5 shows a cross-sectional view of the device of Figure 4 cut line B ₁ -B ₂ .

4 to 5, the thin film type optical path control apparatus according to the present invention includes an active matrix 100, a support element 175 formed on the top of the active matrix 100, and an actuator formed on the support element 175. 210, and a mirror 260 formed on the actuator 210.

The active matrix 100 includes a substrate 101 having M × N (M, N being a natural number) P-MOS transistors 120, a drain 105 and a source 110 of the P-MOS transistors 120. Extending from the first metal layer 135 formed on the substrate 101, the first protective layer 140 formed on the first metal layer 135, and the second metal layer formed on the first protective layer 140. 145, a second passivation layer 150 formed on the second metal layer 145, and an etch stop layer 155 formed on the second passivation layer 150.

Referring to FIG. 4, the support element 175 includes a support line 174, a support layer 170, a first anchor 171, and second anchors 172a and 172b. The support line 174 and the support layer 170 are horizontally formed on the etch stop layer 155 via the first air gap 165. A common electrode line 240 is formed on a portion of the support line 174, and the support line 174 serves to support the common electrode line 240.

The support layer 170 has a rectangular ring shape, preferably a rectangular ring shape, and is integrally formed with the support line 174 along a direction orthogonal to the support line 174 on the same plane. A first anchor 171 is formed integrally with the two arms at a lower portion between two arms horizontally extending in a direction orthogonal to the support line 174 of the support layer 170 to the etch stop layer 155. Two second anchors 172a and 172b are integrally formed with the two arms and attached to the etch stop layer 155 at the outer lower portion of the two arms. The first anchor 171 and the second anchors 172a and 172b each have a shape of a rectangular box.

The support layer 170 is centrally supported by the first anchor 171 and both sides are supported by the second anchors 172a and 172b, so that the cross-sections of the support layer 170 and the anchors 171, 172a and 172b As shown in FIG. 5, it has a 'T' shape.

The first anchor 171 is formed at a portion of the etch stop layer 155 where the drain pad of the first metal layer 135 is located. In the central portion of the first anchor 171, the first metal layer may be formed through the etch stop layer 155, the second passivation layer 150, the holes (not shown) of the second metal layer 145, and the first passivation layer 140. The via hole 270 is formed to the drain pad of the 135, and the via contact 280 is formed inside the via hole 270.

The actuator 210 has a mirror-shaped 'c' shape with respect to the support line 174 and is formed on the support layer 170, and has a lower electrode 180, a first strained layer 190, and a second strained layer ( 191, the first upper electrode 200 and the second upper electrode 201. The lower electrode 180 has a mirror-shaped 'c' shape spaced apart from the support line 174 by a predetermined distance, and is stepped toward the first anchor 171 at both sides of the lower electrode 180. The protrusions are formed corresponding to each other. The protrusions of the lower electrode 180 extend to the periphery of the via hole 270 formed in the first anchor 171, respectively.

The via contact 280 is formed from the drain pad of the first metal layer 135 to the protrusion of the lower electrode 180 through the via hole 280 to electrically connect the drain pad and the lower electrode 180.

The two arms of the lower electrode 180 each have a shape of a rectangular plate, and the first and second deformable layers 190 and 191 each have a shape of a rectangular plate having a narrower area than the two arms of the lower electrode 180. And formed on top of two arms of the lower electrode 180. In addition, the first and second upper electrodes 200 and 201 have a shape of a rectangular plate having a smaller area than the first and second deformable layers 190 and 191, respectively, and have the first and second deformed layers 190 and 191. It is formed at the top of the.

The first insulating layer 220 is formed from one side of the first upper electrode 200 to a part of the support layer 170 through the first strained layer 190 and the lower electrode 180, and the first upper electrode 200. The first upper electrode connecting member 230 is formed from one side of the first insulating layer 220 and the support layer 170 to the common electrode line 240. The first upper electrode connecting member 230 connects the first upper electrode 200 and the common electrode line 240, and the first insulating layer 220 is one side of the first upper electrode 200 and the lower electrode 180. These are connected together to prevent electrical shorts from occurring.

In addition, a second insulating layer 221 is formed from one side of the second upper electrode 201 to a part of the support layer 170 through the second deformable layer 191 and the lower electrode 180. The second upper electrode connecting member 231 is formed from one side of the second upper electrode 201 to the common electrode line 240 through a portion of the second insulating layer 221 and the support layer 170. The second insulating layer 221 and the second upper electrode connecting member 231 are formed to be parallel to the first insulating layer 220 and the first upper electrode connecting member 230, respectively. The second upper electrode connecting member 231 connects the second upper electrode 201 and the common electrode line 240 to each other, and the second insulating layer 221 is formed of the second upper electrode 201 and the lower electrode 180. The other side is connected to each other to prevent electrical short circuit.

Posts for supporting mirrors are formed at portions of the lower '180'-shaped lower electrode 180 where the first and second upper electrodes 200 and 201 are not formed, that is, formed side by side with respect to the support line 174. 250) is formed. A second hard mask 370 having the same shape and size as the mirror 260 is formed between the post 250 and the mirror 260, and the mirror 260 is formed on the second hard mask 370. . The mirror 260 and the second hard mask 370 are supported at the center by the post 250, and both sides thereof are formed horizontally on the actuator 210 via the second air gap 310. The mirror 260 serves to reflect light incident from a light source (not shown) at a predetermined angle.

In the above-described thin film type optical path control apparatus according to the present invention, the first signal transmitted from the outside is the MOS transistor 120 embedded in the active matrix 100, the drain pad and the via contact 280 of the first metal layer 135. Is applied to the lower electrode 180, and at the same time, a second signal is applied to the first and second upper electrodes 200 and 201 through the common electrode line 240 from the outside, respectively, and thus, the first upper electrode 200 is applied. And a first electric field is generated between the one side of the lower electrode 180 and the second electric field according to the potential difference between the second upper electrode 201 and the other side of the lower electrode 180. The first strained layer 190 formed between one side of the first upper electrode 200 and the lower electrode 180 causes deformation by the first electric field, and at the same time, the second upper electrode 201 is caused by the second electric field. And the second strained layer 191 formed between the other side of the lower electrode 180 cause deformation.

As the first and second strained layers 190 and 191 contract in directions perpendicular to the first and second electric fields, respectively, the actuator 210 including the first strained layer 190 has a predetermined angle. It will bend upwards. The mirror 260 reflecting light incident from the light source is inclined together with the actuator 210 because the mirror 260 is supported by the post 250 and is formed on the actuator 210. Accordingly, the mirror 260 reflects incident light at a predetermined angle, and the reflected light passes through the slit to form an image on the screen.

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

6A to 6F are diagrams for describing a method of manufacturing the apparatus shown in FIG. 5. 6A to 6F, the same reference numerals are used for the same members as in FIG.

Referring to FIG. 6A, a device isolation layer 125 is formed on a substrate 101, which is a wafer made of silicon doped with n-type, by using silicon partial oxidation (LOCOS) to distinguish between an active region and a field region. Subsequently, after forming the gate 115 made of a conductive material such as polycrystalline silicon doped with impurities on the active region, the p ⁺ source 110 and the drain 105 are formed by using an ion implantation process. M × N (M and N are natural numbers) P-MOS transistors 120 are formed on the substrate 101.

After the insulating film 130 made of oxide is formed on the P-MOS transistor 120, the upper part of the source 110 and the drain 105 is formed on the insulating film 130 by using a photolithography method. Holes (not shown) that expose each are formed. Subsequently, after depositing a first metal layer 135 made of titanium, titanium nitride, tungsten, nitride, or the like on the insulating layer 130 on which the hole is formed, the first metal layer 135 is patterned by photolithography. The patterned first metal layer 135 includes a drain pad extending from the drain 105 of the P-MOS transistor 120 to the bottom of the first anchor 171 formed later.

The first passivation layer 140 is stacked on the substrate 101 on which the first metal layer 135 and the transistor 120 are formed. The first passivation layer 140 is formed to have a thickness of about 8000 인 by depositing silicate glass (PSG) by chemical vapor deposition (CVD). The first protective layer 140 prevents damage to the substrate 101 in which the transistor 120 is embedded during the subsequent process.

The second metal layer 145 is formed on the first protective layer 140. The second metal layer 145 is formed by sputtering titanium to form a titanium layer having a thickness of about 300 μs, and then depositing titanium nitride on the titanium layer by physical vapor deposition (PVD) to have a thickness of about 1200 μs. It is completed by forming a titanium nitride layer. Since the light incident from the light source is incident not only to the mirror 260 but also to a portion other than the portion covered by the mirror 260, the light leakage current flows through the active matrix 100, causing the device to malfunction. To prevent it. Subsequently, in order to prevent the second metal layer 145 from contacting the via contact 280, a portion of the second metal layer 145 in which the via hole 270 is to be formed in a subsequent process, that is, below the first metal layer 135. The portion where the drain pad is located is etched to form holes (not shown) in the second metal layer 145.

The second passivation layer 150 is stacked on the second metal layer 145. The second protective layer 150 is formed to have a thickness of about 2000 kPa by depositing the silicate glass by chemical vapor deposition. The second protective layer 150 prevents the substrate 101 and the resulting products formed on the substrate 101 from being damaged during subsequent processing.

An etch stop layer 155 is stacked on the second passivation layer 150. The etch stop layer 155 prevents the resultant on the second passivation layer 150 and the substrate 101 from being etched due to the subsequent etching process. The etch stop layer 155 is made of low temperature oxide (LTO) such as silicon oxide (SiO ₂ ) or phosphorus pentoxide (P ₂ O ₅ ). The etch stop layer 155 is formed to have a thickness of about 0.2 to 0.8 μm at a temperature of about 350 to 450 ° C. using a low pressure chemical vapor deposition (LPCVD) method. Accordingly, the substrate 101 having the transistor 120 embedded therein, the first metal layer 135, the first protective layer 140, the second metal layer 145, the second protective layer 150, and the etch stop layer 155 may be formed. The active matrix 100 is completed.

The first sacrificial layer 160 is stacked on the etch stop layer 155. The first sacrificial layer 160 serves to facilitate stacking of the thin films constituting the actuator 210. The first sacrificial layer 160 is formed to have a thickness of about 2.0 to 3.0 μm by using low pressure chemical vapor deposition (LPCVD) at a temperature of about 500 ° C. or less. Subsequently, the surface of the first sacrificial layer 160 is polished using a chemical mechanical polishing (CMP) method to planarize the surface of the first sacrificial layer 160 to have a thickness of about 1.1 μm.

6B is a plan view illustrating a state in which the first sacrificial layer 160 is patterned. 6A and 6B, after applying and patterning a first photoresist (not shown) on the first sacrificial layer 160, the first sacrificial layer is formed using the first photoresist as a mask. A portion of the second anti-etching layer 155 is etched by etching the portion of the second metal layer 145 in which the hole (not shown) of the second metal layer 145 is formed and the portions adjacent to both sides thereof, thereby exposing the first anchor 171 and The position where the second anchors 172a and 172b are to be formed is made. Thus, the etch stop layer 155 is exposed in the shape of three squares spaced apart by a predetermined distance. Subsequently, the first photoresist is removed.

Referring to FIG. 6C, the first layer 169 is stacked on the upper portion of the etch stop layer 155 and the first sacrificial layer 160 exposed in the shape of a rectangle as described above. The first layer 169 is formed by depositing a hard material such as nitride or metal by low pressure chemical vapor deposition (LPCVD) to have a thickness of about 0.1 to 1.0 μm. First layer 169 is later patterned with support element 175 including support layer 170, support line 174 and anchors 171, 172a, 172b.

The lower electrode layer 179 is stacked on top of the first layer 179. The lower electrode layer 179 is formed by depositing a metal having electrical conductivity such as platinum (Pt), tantalum (Ta), or platinum-tantalum (Pt-Ta) by a sputtering method or a chemical vapor deposition method, and having a thickness of about 0.1 to 1.0 μm. Form to have. The lower electrode layer 179 is later applied with a first signal (image signal) from the outside and patterned into a lower electrode 180 having a mirror-shaped 'c' shape.

A second layer 189 made of a piezoelectric material such as PZT or PLZT is stacked on the lower electrode 179. Preferably, the second layer 189 is formed to have a thickness of about 0.4 μm by spin coating PZT prepared by the sol-gel method. Subsequently, the piezoelectric material constituting the second layer 189 is subjected to heat treatment by rapid thermal treatment (RTA) to cause phase shift. The second layer 189 may be the first strained layer 190 and the second upper electrode 210 which are deformed by a first electric field generated between the first upper electrode 200 and the lower electrode 180 later. And a second deformation layer 191 causing deformation by a second electric field generated between the other side of the lower electrode 180 and the other side.

The upper electrode layer 199 is stacked on top of the second layer 189. The upper electrode layer 199 is formed to have a thickness of about 0.1 to 1.0 μm by depositing a metal having electrical conductivity such as platinum, tantalum, silver, or platinum-tantalum by sputtering or chemical vapor deposition. The upper electrode layer 199 is later patterned with the first and second upper electrodes 200 and 201 to which second signals (bias signals) are respectively applied and spaced apart by a predetermined distance.

Referring to FIG. 6D, after applying and patterning a second photoresist (not shown) on the upper electrode layer 199, each of the upper electrode layers 199 may be formed using a second photoresist as a mask. The first upper electrode 200 and the second upper electrode 201 are formed in a shape, preferably a rectangular flat plate, and are formed to be spaced apart from each other by a predetermined distance. The second signal is applied to the first and second upper electrodes 200 and 201 through the common electrode line 240 formed later from the outside, respectively. Subsequently, the second photoresist is removed.

Subsequently, by patterning the second layer 189 in the same manner as the method of patterning the upper electrode layer 199, each of the first strained layers 190 having a shape of a rectangular flat plate and formed side by side with a predetermined distance therebetween. And a second strained layer 191. In this case, as shown in FIG. 4, the first and second deformable layers 190 and 191 are patterned to have a rectangular flat plate shape slightly wider than the first and second upper electrodes 200 and 201, respectively.

Subsequently, the lower electrode layer 179 is patterned in the same manner as the patterning of the upper electrode layer 199 to have a mirror-shaped 'C' shape for the support line 174 formed later, and the first side portions may be formed on both inner sides thereof. A lower electrode 180 having a protrusion formed in a step shape toward the anchor 171 is formed. In this case, the two arms of the lower electrode 180 have the shape of a rectangular flat plate having a larger area than the first and second strained layers 190 and 191, respectively.

In addition, when the lower electrode layer 179 is patterned, the common electrode line 240 is formed simultaneously with the lower electrode 180 in a direction perpendicular to the lower electrode 180 on one side of the first layer 169. The common electrode line 240 is formed to be spaced apart from the lower electrode 180 by a predetermined distance on the support line 174 formed later. Thus, the actuator 210 including the first and second upper electrodes 200 and 201, the first and second strained layers 190 and 191, and the lower electrode 180 is completed.

Subsequently, the first layer 169 is patterned to form a support element 175 comprising a support layer 170, a support line 174, a first anchor 171 and second anchors 172a and 172b. . At this time, both sides of the portion of the first layer 169 that contacts the etch stop layer 155 exposed in the shape of the three quadrangles become second anchors 172a and 172b, and the center portion of the first anchor 171 ) Each of the first anchor 171 and the second anchors 172a and 172b has a rectangular box shape, and a hole (not shown) and a first hole of the second metal layer 145 are disposed below the first anchor 171. The drain pad of the metal layer 135 is located.

The first and second upper electrodes 200 and 201 are formed parallel to each other on top of two arms horizontally extending in a direction orthogonal to the support line 174 of the support layer 170, respectively. Accordingly, the first anchor 171 is formed below the lower electrode 180, and the second anchors 172a and 172b are formed below the outer electrode 180, respectively.

Subsequently, a third photoresist (not shown) is applied and patterned on top of the support element 175 including the support layer 170 and the support line 174 and on the actuator 210 to pattern the support line 174. A portion of the first and second upper electrodes 200 and 201 are exposed from the common electrode line 240 formed on the second electrode. At this time, the protrusions of the lower electrode 180 are also exposed together from the first anchor 171.

Subsequently, the first strained layer 190 and the lower electrode 180 may be removed from a portion of the first upper electrode 200 by depositing and patterning amorphous silicon or silicon oxide or phosphorus pentoxide, which is a low temperature oxide, on the exposed portion. The first insulating layer 220 is formed up to a part of the support layer 170, and at the same time, the support layer 170 is formed through the second strained layer 191 and the lower electrode 180 from a part of the second upper electrode 201. The second insulating layer 221 is formed to a part. The first and second insulating layers 220 and 221 are formed to have a thickness of about 0.2 to 0.4 µm, and preferably about 0.3 µm, respectively, using low pressure chemical vapor deposition (LPCVD).

The first anchor 171, the etch stop layer 155, and the first anchor 171 are formed from the center of the first anchor 171, which is a portion where the hole of the second metal layer 145 and the drain pad of the first metal layer 135 are positioned. After the second protective layer 150 and the first protective layer 140 are etched to form the via hole 270 to the drain pad, the via contact is extended from the drain pad to the protrusions of the lower electrode 180 through the via hole 270. 280). At the same time, the first upper electrode connecting member 230 and the second upper electrode 201 extend from the first upper electrode 200 to the common electrode line 240 through a part of the first insulating layer 220 and the support layer 170. The second upper electrode connecting member 231 is formed from the second insulating layer 221 and the support layer 170 to the common electrode line 240.

The via contact 280 and the first and second upper electrode connection members 230 and 231 are deposited with platinum or platinum-tantalum to have a thickness of about 0.1 to 0.2 μm by sputtering or chemical vapor deposition. Then, the deposited metal is formed by patterning. The first and second upper electrode connecting members 230 and 231 connect the first and second upper electrodes 200 and 201 and the common electrode line 240, respectively, and the lower electrode 180 connects the via contact 280. It is connected to the drain pad of the first metal layer 135 through.

Referring to FIG. 6E, after the photoresist protective layer 320 is formed on the front surface of the active matrix 100 on which the support element 175 and the actuator 210 are formed, the hardness of the photoresist protective layer 320 is increased. And a first hard mask 330 made of a metal having high thermal stability. Subsequently, after applying and patterning the fourth photoresist 340 on the back surface of the active matrix 100, the back surface of the active matrix 100 is formed to a predetermined depth by using the patterned fourth photoresist 340 as a mask. By etching, a plurality of irregularities are formed on the back surface of the active matrix 100. As such, by forming a plurality of uneven parts on the rear surface of the active matrix 100, a bow phenomenon in which both ends of the TMA module are bent after the manufacturing process of the device is completed can be prevented. In this case, since the first hard mask 330 made of metal has high hardness and thermal stability, an actuator formed on the front surface of the active matrix 100 during the photolithography process for patterning the back surface of the active matrix 100 ( 210 can be protected from scratches and dust.

Referring to FIG. 6F, after the first hard mask 330, the fourth photoresist 340, and the photoresist protective layer 320 are removed, an acuflow is formed on the support element 175 and the actuator 210. To form the second sacrificial layer 300. This accuflow is applied on top of the actuator 210 and the support element 175 using a spin coating method and subsequently removed using an ashing method.

Subsequently, after applying a fifth photoresist (not shown) on the second sacrificial layer 300, a second hard mask 370 made of aluminum or silicon oxide is formed on the fifth photoresist, After the second hard mask 370 is patterned by the photolithography method, the fifth photoresist and the second sacrificial layer 300 are patterned along the second hard mask 370 pattern to form a lower portion of the mirror image 'c'. The post 180 may be exposed by exposing a portion of the portion formed in parallel with and not adjacent to the stop line 174 of the electrode 180 (that is, the portion where the first and second upper electrodes 200 and 201 are not formed thereon). 250 forms a post hole to be formed.

Subsequently, aluminum is deposited on the exposed lower electrode 180 and the second hard mask 370 to a thickness of about 0.1 to 1.0 μm using a sputtering method or a chemical vapor deposition method. By patterning to form a mirror 260 having a shape of a square flat plate and a post 250 for supporting the mirror 260 at the same time.

After the second sacrificial layer 300 and the fifth photoresist are removed by plasma ashing, the first sacrificial layer 160 is removed using xenon fluoride (XeF ₂ ) or bromine fluoride (BrF ₂ ). Cleaning and drying treatments are performed to complete the TMA device as shown in FIG. As described above, when the second sacrificial layer 300 and the fifth photoresist are removed, a second air gap 310 is formed at positions of the second sacrificial layer 300 and the fifth photoresist, and the first sacrificial layer 160 is formed. When this is removed, the first air gap 165 is formed at the position of the first sacrificial layer 160.

7 is a manufacturing process chart of a thin film type optical path control device according to another embodiment of the present invention.

Referring to FIG. 7, after the same processes as described above with reference to FIGS. 6A to 6D, the hardness and thermal stability of the active matrix 100 on which the support element 175 and the actuator 210 are formed are high. The protective layer 350 made of high accuflo is laminated to a thickness of about 5 μm or more. Subsequently, after applying and patterning the fourth photoresist 340 on the back surface of the active matrix 100, the back surface of the active matrix 100 is etched to a predetermined depth using the patterned fourth photoresist 340 as a mask. As a result, a plurality of irregularities are formed on the rear surface of the active matrix 100. In this case, the acuflo protective layer 350 has a very stable property as the thermal deformation progresses, not only the hardness is high but the thermal stability is about 300 ° C. or higher. In addition, since the acuflo protective layer 350 may be formed to a thickness of about 5 μm or more, an actuator due to scratches or dust generated in contact with equipment during a photolithography process for patterning the back surface of the active matrix 100. Damage to the 210 can be prevented. Subsequently, after the acuflo protective layer 350 is removed by an ashing method, the manufacturing process of FIG. 6F described above is performed in the same manner to form a TMA element.

According to the manufacturing method of the thin film type optical path control apparatus according to the present invention, after forming a hard mask made of a photoresist protective layer and a metal or an acuflo protective layer on the front surface of the active matrix on which the supporting element and the actuator are formed, a photolithography method To pattern the back side of the active matrix. Since the metal hard mask or AccuFlu protective layer is harder than photoresist, no scratch occurs even when contacted with photographic or etching equipment. Therefore, during the photolithography process for patterning the back surface of the active matrix, the actuator formed on the front surface of the active matrix can be safely protected from scratches and dust. In addition, since the metal hard mask and the acuflo protective layer have higher thermal stability than the photoresist, automation by a hot plate during the photolithography process is possible.

As described above, although described with reference to a preferred embodiment of the present invention, those skilled in the art will be modified in various ways without departing from the spirit and scope of the invention described in the claims below. And can be changed.

Claims (3)

Providing an active matrix including a first metal layer having a MOS transistor embedded therein and having a drain pad extending from the drain of the transistor; Forming a first layer, a lower electrode layer, a second layer, and an upper electrode layer on the active matrix; Patterning the upper electrode layer, the second layer and the lower electrode to form an actuator including a lower electrode, first and second strained layers, and first and second upper electrodes; Patterning the first layer to form support means including support lines, support layers, and anchors; Stacking a photoresist and a hard mask on the support means and the actuator, and patterning a back surface of the active matrix; Removing the photoresist protective layer and the hard mask; And Method of manufacturing a thin film type optical path control device comprising the step of forming a mirror on top of the actuator. The method of claim 1, wherein the hard mask is formed of a metal material having high hardness and thermal stability. Providing an active matrix including a first metal layer having a MOS transistor embedded therein and having a drain pad extending from the drain of the transistor; Forming a first layer, a lower electrode, a second layer, and an upper electrode layer on the active matrix; Patterning the upper electrode layer, the second layer and the lower electrode layer to form an actuator including a lower electrode, first and second strained layers, and first and second upper electrodes; Patterning the first layer to form support means including support lines, support layers, and anchors; Patterning a back surface of the active matrix after forming a protective layer made of accuflo on the support means and the actuator; Removing the accul protective layer; And Method of manufacturing a thin film type optical path control device comprising the step of forming a mirror on top of the actuator.