KR20000004791A - Thin film actuated mirror array and method for manufacturing thereof - Google Patents

Abstract

PURPOSE: A thin film actuated mirrors array in an optical projection system is provided to preventing a point defect of pixel by preventing an effect in which an actuator are sticked on an active matrix. CONSTITUTION: The thin film actuated mirrors array comprising an active matrix (100) including a first metal layer (135), which a MOS transistor (120) is built-in and a drain pad of the transistor (120) extending from a drain of the transistor; a supporter (175) including i) a support line (174) formed onto the active matrix (100), ii) a support layer (170) formed integral with the support line and having a circular shape of rectangular, iii) a first anchor (171) and a second anchor (172a, 172b) supporting a support layer(170); an actuator (210) including a lower electrode (180), a first deformable layer (190), a second deformable layer (191), a first upper electrode (200), and a second electrode (201); a plurality of etching hole (290, 291) formed from one side of the first and the second upper electrode (200, 201) through the first and the second deformable layer (190, 191), the lower electrode (180), and the support layer(170); and a mirror formed onto the actuator (210).

Description

Thin film type optical path control device and its manufacturing method

The present invention relates to a method for manufacturing a thin film type optical path control device using an Actuated Mirror Array (AMA), and more particularly, to prevent point defects of pixels due to sticking of an actuator. It relates to a thin film type optical path control device and a method of manufacturing the same.

Optical path control devices or spatial light modulators for projecting optical energy onto the screen can be applied to a variety of applications such as optical communications, 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 type 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 an increase in manufacturing cost. There is. The projection image display device may 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 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, 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 in the 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. The AMA reflects light incident from a light source at each angle installed inside the mirror, and the reflected light is projected on a screen through an aperture such as a slit or pinhole to form an image. It is a device that can adjust the speed of light. 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.

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 to form an image on the screen.

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 cuts a thin layer of multilayer ceramic, mounts a ceramic wafer having a metal electrode therein in an active matrix including a transistor, and then processes it using a sawing method and mirrors the upper portion thereof. By installing. However, the bulk optical path control device requires very high precision in design and manufacturing, and has a disadvantage in that the response of the strained layer is slow.

Accordingly, a thin film type optical path control apparatus that can be manufactured using a semiconductor manufacturing process has been developed. Such a thin film type optical path control device is disclosed in Korean Patent Application No. 98-16545 (name of the invention: thin film type optical path control device and its manufacturing method) filed by the applicant of the Korean Patent Office on May 8, 1998.

FIG. 1 shows a perspective view of a thin film type optical path adjusting device described in the above prior application, and FIG. 2 shows a cross-sectional view of the device of FIG. 1 taken along 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, first and second actuators 90 and 91, and a mirror 99. .

The active matrix 1 is formed from a substrate 2 having M × N (M, where N is a natural number) P-MOS transistors 10, a drain 3 and a source 5 of the transistor 10. The first metal layer 20 formed on the substrate 2, the first protective layer 25, the second metal layer 30, and the second protective layer 35 sequentially formed on the first metal layer 20. ) And an etch stop layer 40.

The support element 75 includes a support line 74 formed on top of the active matrix 1, a support layer 73 formed integrally with the support line 74 and having a rectangular ring shape, and the support layer 73. The first anchor 71 and the second anchors 72a and 72b respectively contact the active matrix 1 under the portion adjacent to the middle support line 74 to support the support layer 73.

The first and second actuating parts 90 and 91 are formed in parallel with each other in a rectangular flat plate shape on the two arms of the square annular support layer 73, respectively. The first actuating part 90 includes a first lower electrode 80, a first deforming layer 82, and a first upper electrode 85, and the second actuating part 91 includes a second lower electrode ( 81, a second strained layer 83, and a second upper electrode 86.

The mirror 99 is centrally supported by the post 98 and both sides are formed horizontally on the first and second actuating portions 90 and 91 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 show a manufacturing process diagram of the apparatus shown in FIG. 2.

Referring to FIG. 3A, a device isolation layer 15 is formed on a substrate 2, which is a silicon wafer, by using a silicon partial oxidation method (LOCOS), which is a conventional device isolation process, to distinguish between an active region and a field region. Subsequently, a gate 16 made of a conductive material such as poly-silicon is formed on the active region, and then p ⁺ source 5 and drain 3 are formed using an ion implantation process. As a result, M x N (M and N are natural numbers) P-MOS transistors 10 are formed on the substrate 2.

After the insulating film 17 made of oxide is formed on the substrate 2 on which the P-MOS transistor 10 is formed, an upper portion of one side of the source 5 and the drain 3 is respectively formed using a photolithography method. Form openings that expose. Subsequently, after depositing the first metal layer 20 made of titanium, titanium nitride, tungsten, nitride, or the like on the resultant, the first metal layer 20 is patterned by a photolithography method. The patterned first metal layer 20 includes a drain pad extending from the drain 3 of the P-MOS transistor 10 to the first anchor 71 supporting the support layer 73.

The first passivation layer 25 is formed on the first metal layer 20 and the substrate 2. The first protective layer 25 is formed of phosphorous silicate (PSG) to have a thickness of about 8000 kPa by chemical vapor deposition (CVD). The first protective layer 25 prevents damage to the substrate 2 in which the transistor 10 is embedded during subsequent processing.

The second metal layer 30 is formed on the first protective layer 25. The second metal layer 30 is formed by sputtering titanium to form a titanium layer having a thickness of about 300 kV, and then depositing titanium nitride on the titanium layer by physical vapor deposition (PVD) to form a titanium nitride layer. Since the light incident from the light source is incident not only on the mirror 99 but also on a portion other than the portion covered by the mirror 99, the second metal layer 30 causes a photocurrent to flow in the active matrix 1, causing the device to malfunction. To prevent them. Subsequently, a portion of the second metal layer 30 in which the via hole 50 is to be formed in a subsequent process, that is, a portion in which the drain pad of the first metal layer 20 is formed is etched to the second metal layer 30. Form a hole (not shown).

The second passivation layer 35 is stacked on the second metal layer 30. The second protective layer 35 is formed to have a thickness of about 2000 GPa by using the silicate glass PSG by chemical vapor deposition. The second protective layer 35 prevents the substrate 2 and the results formed on the substrate 2 from being damaged during subsequent processing.

An etch stop layer 40 is stacked on the second passivation layer 35. The etch stop layer 40 prevents the second passivation layer 35 and the products on the active matrix 1 from being etched due to the subsequent etching process. The etch stop layer 40 is made of low temperature oxide (LTO) such as silicon oxide (SiO ₂ ) or phosphorus pentoxide (P ₂ O ₅ ). The etch stop layer 40 is formed to have a thickness of about 0.2 to 0.8 μm by low pressure chemical vapor deposition (LPCVD).

The first sacrificial layer 45 is stacked on the etch stop layer 40. The first sacrificial layer 45 serves to facilitate stacking of the thin films constituting the first and second actuators 90 and 91. The first sacrificial layer 45 is formed of poly-silicon to have a thickness of about 2.0 to 3.0 μm by low pressure chemical vapor deposition (LPCVD). 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 about 1.1 μm.

Subsequently, after applying and patterning a first photoresist (not shown) on top of the first sacrificial layer 45, the first photoresist is used as a mask and below the first sacrificial layer 45. The first anchors 71 and the second supporting the supporting layer 73 are formed by etching the portions in which the holes of the second metal layer 30 and the portions adjacent to both sides are etched to expose a portion of the etch stop layer 40. Make the position where anchors 72a and 72b are to be formed. Accordingly, the etch stop layer 40 is exposed in the shape of three squares spaced apart by a predetermined distance. Then, the first photoresist is removed.

The first layer 69 is stacked on the etch stop layer 40 and the first sacrificial layer 45 exposed in the shape of a rectangle as described above. The first layer 69 is formed to have a thickness of about 0.1 μm to about 1.0 μm by using a low pressure chemical vapor deposition (LPCVD) method. The first layer 69 is later patterned with a support element 75, which supports the support layer 73, the common electrode line 77, for supporting the first and second actuating portions 90, 91. It consists of a support line 74 for supporting and a first anchor 71 and second anchors 72a, 72b for supporting the support layer 73. In this case, a portion of the first layer 69 attached to the etch stop layer 40 having a center shape among the portions attached to the etch stop layer 40 exposed in the shape of the three rectangles is the first anchor 71. The portions attached to both sides of the rectangular anti-etching layer 40 become second anchors 72a and 72b.

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 about 0.1 μm to 1.0 μm using a metal such as platinum (Pt), tantalum (Ta), or platinum-tantalum (Pt-Ta) using a sputtering method or a chemical vapor deposition method. The lower electrode layer 79 is later patterned with first and second lower electrodes 80 and 81 which are respectively applied with a first signal (image signal) from the outside and spaced apart by a predetermined distance.

A second layer 59 made of a piezoelectric material such as PZT or PLZT is stacked on the lower electrode layer 79. The second layer 59 is formed to have a thickness of about 0.1 to 1.0 mu m using a sol-gel method, a sputtering method, or a chemical vapor deposition method. Preferably, the second layer 59 is formed to have a thickness of about 0.4 μm by sputtering PZT manufactured by the sol-gel method. Subsequently, the piezoelectric material constituting the second layer 59 is subjected to heat treatment by a rapid heat treatment (RTA) method 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 of a metal such as platinum, tantalum, silver (Ag), or platinum-tantalum to have a thickness of about 0.1 μm to 1.0 μm using 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 is formed on a rectangular flat plate using the second photoresist as a mask. The first and second upper electrodes 85 and 86 have a shape and are spaced apart from each other by a predetermined distance to be patterned (see FIG. 1). The second 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 method of patterning the upper electrode layer 87 to form a rectangular flat plate, and the first and second strained layers formed side by side with a predetermined distance apart from each other. (82, 83) are formed. In this case, as shown in FIG. 1, the first and second strained layers 82 and 83 are patterned to have a shape of a rectangular plate slightly wider than the first and second upper electrodes 85 and 86, respectively.

Subsequently, the lower electrode layer 79 is patterned by the same method as described above to form first and second lower electrodes 80 and 81, each having a rectangular flat plate shape and separated from each other by a predetermined distance. In addition, when the lower electrode layer 79 is patterned, the common electrode line 77 is first and second in a direction perpendicular to the first and second lower electrodes 80 and 81 on one side of the first layer 69. It is formed simultaneously with the lower electrodes 80 and 81. The first and second lower electrodes 80 and 81 have a slightly larger area than the first and second deformable layers 82 and 83, respectively, and the common electrode line 77 is formed on an upper portion of the support line 74 formed later. The first and second lower electrodes 80 and 81 are spaced apart from each other by a predetermined distance. Therefore, the first actuating part 90 including the first upper electrode 85, the first strained layer 82, and the first lower electrode 80, the second upper electrode 86, and the second strained layer ( The second actuating part 91 including the 83 and the second lower electrode 81 is completed.

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 contacting the etch stop layer 40 exposed in the shape of the three quadrangles are the second anchors 72a and 72b, and the center portion of the first layer 69 is the first anchor 71. ) Each of the first anchor 71 and the second anchors 72a and 72b has a rectangular box shape, and a hole of the second metal layer 30 is formed under the first anchor 71. The support layer 73 has a rectangular ring shape and is integrally formed with the support line 74. In this state, when the first sacrificial layer 45 is later removed, a support element 75 having a shape as shown in FIG. 1 is formed. A first anchor 71 is integrally formed with the two arms and etched in a lower portion between two arms horizontally extending in a direction orthogonal to the support line 74 among the support layers 73 having a rectangular ring shape. Attached to the barrier layer 40, two second anchors 72a and 72b are respectively formed integrally with the two arms and attached to the etch stop layer 40 at the outer lower portion of the two arms. The first anchor 71 and the second anchors 72a and 72b together supporting the support layer 73 are formed in the lower portion of the support layer 73 adjacent to the support line 74.

The first and second actuating parts 90 and 91 are formed parallel to each other on top of two arms horizontally extending in a direction orthogonal to the support line 74 of the support layer 73. Accordingly, the first anchor 71 is formed between the first and second actuating parts 90 and 91, and the second anchors 72a and 72b are respectively formed on the outer side and the first of the first actuating part 90. 2 is formed on the outer side of the actuating portion 91.

Referring to FIG. 3C, a third photoresist (not shown) is applied and patterned on top of the support element 75, the first and second actuating portions 90, 91, onto the support line 74. Portions of the first and second upper electrodes 85 and 86 are exposed from the common electrode line 77 formed at the upper portion thereof. At this time, a part of the first and second lower electrodes 80 and 81 are also exposed together from the first anchor 71.

Subsequently, by depositing and patterning amorphous silicon or silicon oxide or phosphorus pentoxide, which is a low temperature oxide, on the exposed portion, the first strained layer 82 and the first lower portion from a part of the first upper electrode 85 are patterned. The first insulating layer 65 is formed through the electrode 80 to a part of the support layer 73, and at the same time, the second deformable layer 83 and the second lower electrode 81 from a part of the second upper electrode 86. The second insulating layer 66 is formed to a part of the supporting layer 73 through the second insulating layer 66. The first and second insulating layers 65 and 66 are formed to have a thickness of about 0.2 to 0.4 µm, respectively, using a low pressure chemical vapor deposition (LPCVD) method.

Subsequently, the first anchor 71, the etch stop layer 40, and the first anchor 71 are formed from a central portion of the first anchor 71, which is a portion where the hole of the second metal layer 30 and the drain pad of the first metal layer 20 are formed below. After the second protective layer 35 and the first protective layer 25 are etched to form the via hole 50 to the drain pad, a via contact 60 is formed in the via hole 50, and the via hole 50 is formed. The first and second lower electrode connecting members 88 and 89 are formed from 50 to the first and second lower electrodes 80 and 81, respectively (see FIG. 1). At the same time, the first upper electrode connecting member 67 is formed from the first upper electrode 85 to the common electrode line 77 through a portion of the first insulating layer 65 and the supporting layer 73, and the second upper electrode The second upper electrode connecting member 68 is formed from the 86 through the second insulating layer 66 and the support layer 73 to the common electrode line 77.

The via contact 60, the first and second lower electrode connecting members 88 and 89, and the first and second upper electrode connecting members 67 and 68 respectively sputter platinum or platinum-tantalum by sputtering or chemical vapor deposition. After the deposition by a method having a thickness of about 0.1 ~ 0.2㎛, and formed by patterning the deposited metal. The first and second upper electrode connecting members 67 and 68 connect the first and second upper electrodes 85 and 86 to the common electrode line 77, respectively, and the first lower electrode 80 is connected to the first lower electrode. It is connected to the drain pad of the first metal layer 20 through the connecting member 88 and the via contact 60, the second lower electrode 81 is connected to the second lower electrode connecting member 89 and the via contact 60. It is connected to the drain pad through.

Referring to FIG. 3D, the first and second actuators 90, 91 are formed on top of the first and second actuators 90, 91 and the support element 75 by a low pressure chemical vapor deposition method. ) Is formed a second sacrificial layer (95) having a sufficient height to cover. Subsequently, the surface of the second sacrificial layer 95 is planarized by using a chemical mechanical polishing (CMP) method so that the top of the second sacrificial layer 95 has a flat surface. Subsequently, by patterning the second sacrificial layer 95 to form the mirrors 99 and the posts 98, parallel to the support lines 74 of the support layers 73 having the shape of the square rings, without being adjacent to each other. Expose a portion of the formed part. Next, a metal such as aluminum (Al) is deposited on a part of the exposed support layer 73 and on the second sacrificial layer 95 by using a sputtering method or a chemical vapor deposition method, and patterning the deposited metal. A mirror 99 having a rectangular flat plate shape and a post 95 supporting the mirror 99 are simultaneously formed.

In addition, the first sacrificial layer 45 and the second sacrificial layer 95 are removed using xenon fluoride (XeF ₂ ) or bromine fluoride (BrF ₂ ), and the cleaning and drying treatments are performed to remove the first sacrificial layer 45 and the second sacrificial layer 95. Complete the AMA device as shown. 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.

However, in the removal of the first sacrificial layer and the second sacrificial layer using xenon fluoride or bromide fluoride, as described above, the first and second sacrificial layers may be removed from the outside of the first and second actuating portions. Etching of the constituent material poly-silicon starts, so that the poly-silicon at the bottom of the support layer is not completely removed, and therefore, even after the first and second sacrificial layers are removed, the ends of the two arms of the support layer are due to the residues. The so-called sticking phenomenon occurs, in which portions (see D ₁ and D _{2 in} FIG. 1) stick to the etch stop layer on the active matrix. In this way, when the actuator is attached to the active matrix, the actuator does not drive even when a signal is applied, resulting in a point defect of the pixel.

Accordingly, it is an object of the present invention to provide a thin film type optical path control apparatus and a method of manufacturing the same which can prevent a point defect of a pixel by forming a plurality of etching holes in the actuator to prevent the actuator from sticking.

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. 2.

Figure 4 is a perspective view of a thin film type optical path control apparatus according to 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 6E are manufacturing process diagrams of the apparatus shown in FIGS. 4 and 5.

<Explanation of symbols for the main parts of the drawings>

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: actuator

220, 221: first and second insulating layer 250: post

260: mirror 270: empty hall

280: via contact 290, 291: first and second etching holes

300: second sacrificial layer

In order to achieve the above object, the present invention provides an active matrix including a first metal layer in which a MOS transistor is embedded and having a drain pad extending from a drain of the transistor, a support line, a support layer, a first anchor, and an upper portion of the active matrix. A support element formed with second anchors, an actuator formed on top of the support element, and a mirror formed on top of the actuator. The actuator may include a lower electrode formed on an upper portion of the support layer, a first strained layer formed on an upper side of one side of the lower electrode, a second strained layer formed on the other side of the lower electrode, and a first formed on the first strained layer. And an upper electrode, and a second upper electrode formed on the second strained layer. A plurality of etching holes are formed from one side of the first and second upper electrodes through the first and second strained layers, the lower electrode, and the support layer.

In addition, in order to achieve the above object, the present invention provides an active matrix comprising a first metal layer having an M x N MOS transistor embedded therein and having a drain pad extending from the drain of the transistor, Forming a first sacrificial layer on the upper portion, forming a first layer, a lower electrode layer, a second layer, and an upper electrode layer on the first sacrificial layer, and forming the upper electrode layer, the second layer, and the lower electrode layer. Patterning to form an actuator including a first upper electrode, a second upper electrode, a first strained layer, a second strained layer, and a lower electrode; patterning the first layer to support a support line, a support layer, and a first anchor and a first Forming a support element comprising two anchors, the plurality of edges penetrating the support layer from one side of the first upper electrode and the second upper electrode, respectively; Forming a hole, and provides a process for the production of thin-film optical path control device comprising: after forming the second sacrificial layer on the top of the actuator to form a mirror.

According to the present invention, first and second etching holes are respectively formed to penetrate the support layer from the first and second upper electrodes on both sides of the post, and the sacrificial layer is formed through the first and second etching holes simultaneously with the outer portion of the actuator. By etching, the supporting layer may be prevented from adhering to the etch stop layer, thereby preventing the actuator from sticking to the active matrix, thereby preventing the point defect of the pixel.

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

Figure 4 shows a perspective view of a 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 along the line B ₁ B ₂ .

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

Referring to FIG. 5, the active matrix 100 includes a substrate 101 having M × N (M, N being a natural number) P-MOS transistors 120, and a drain 105 of the MOS transistors 120. ) Of the first metal layer 135 formed on the substrate 101, the first protective layer 140 formed on the first metal layer 135, and the first protective layer 140 extending from the source 110. The second metal layer 145 formed on the upper portion, the second protective layer 150 formed on the second metal layer 145, and the etch stop layer 155 formed on the second protective layer 150 are included.

Referring to FIG. 4, the support element 175 may include a support line 174 formed on the active matrix 100, a support layer 170 integrally formed with the support line 174, and having a rectangular ring shape. The first anchor 171 and the second anchors 172a and 172b which contact the active matrix 100 below the portion of the support layer 170 adjacent to the support line 174 to support the support layer 170, respectively. Include. The common electrode line 240 is formed on the support line 174, and the support line 174 functions to support the common electrode line 240.

The actuator 210 includes a lower electrode 180, a first strained layer 190, a second strained layer 191, a first upper electrode 200, and a second upper electrode 201. The lower electrode 180 is formed in a mirror-shaped 'c' shape spaced apart from the support line 174 by a predetermined distance on an upper portion of the support layer 170 having a rectangular ring shape, and the first and second deformed layers. 190 and 191 are formed in the shape of a rectangular flat plate on the two arms of the lower electrode 180, respectively, and the first and second upper electrodes 200 and 201 are formed of the first and second strained layers, respectively. 190 and 191 are formed in the shape of a rectangular flat plate having a smaller area than the first and second strained layers 190 and 191. The lower electrode 180 having a mirror-shaped 'c' shape has protrusions extending in a downward direction toward the first anchor 171. The protrusions of the lower electrode 180 extend to a part of the first anchor 171 corresponding to each other.

The first anchor 171 is formed on a portion in which the drain pad of the first metal layer 135 is formed below the etch stop layer 155. In the central portion of the first anchor 171, the first metal layer 135 is formed through the etch stop layer 155, the second passivation layer 150, the hole 147 of the second metal layer 145, and the first passivation layer 140. The via hole 270 is formed to the drain pad of the. The first anchor 171 is formed between the lower portion of the mirror-shaped 'c' shaped lower electrode 180, and the second anchors 172a and 172b are formed on the outer lower portion of the lower electrode 180, respectively. .

The via contact 280 formed in the via hole 270 extends from the drain pad to the protrusions of the lower electrode 180 through the via hole 270 to connect the drain pad and the lower electrode 180.

A first insulating layer 220 is formed from a portion of the first upper electrode 200 to a portion of the support layer 170 through the first deforming layer 190 and the lower electrode 180, and the first upper electrode connecting member. 230 is formed to the common electrode line 240 through a portion of the first insulating layer 220 and the support layer 170. 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 has the first upper electrode 200 and the lower electrode 180 mutually connected to each other. Connected to prevent electrical shorts between them.

In addition, a second insulating layer 221 is formed from a portion of the second upper electrode 201 to a portion of the support layer 170 through the second deforming layer 191 and the lower electrode 180, and connects the second upper electrode. The member 231 is formed to the common electrode line 240 through a portion of the second insulating layer 221 and the support layer 170. The second upper electrode connecting member 231 connects the second upper electrode 201 and the common electrode line 240, and the second insulating layer 221 has the second upper electrode 201 and the lower electrode 180 mutually connected to each other. Connection to prevent electrical shorts between them. The second upper electrode connecting member 231 and the second insulating layer 221 are formed in parallel with the first upper electrode connecting member 230 and the first insulating layer 220, respectively.

The post 250 is formed on a part of the lower electrode 180 having the shape of 'mirror' on the mirror in which the first and second upper electrodes 200 and 201 are not formed, and the mirror 260 is a post. The central portion is supported by the 250, and both sides thereof are horizontally formed on the upper portion of the actuator 210 via the second air gap 310. The mirror 260 reflects the light incident from the light source (not shown) at a predetermined angle so that the image is projected onto the screen (not shown).

A portion of the first and second upper electrodes 200 and 201 on both sides of the post 250, that is, end portions of the two arms of the support layer 170, respectively, may include first and second etching holes 290 and 291, respectively. Is formed. The first etching hole 290 is formed from the first upper electrode 200 through one of two arms of the first deforming layer 190, the lower electrode 180, and the support layer 170, and the second etching is performed. The hole 291 is also formed through the other one of the two arms of the second deformable layer 191, the lower electrode 180, and the support layer 170 from the second upper electrode 201. The first and second etching holes 290 and 291 may allow the first and second sacrificial layers 160 and 300 to be easily removed without residues, so that the support layer 170 may prevent the etch stop layer 155. It is attached to the actuator 210 to prevent causing sticking.

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

6A to 6F are diagrams for describing a method of manufacturing the apparatus shown in FIGS. 4 and 5. In Figs. 6A to 6F, the same reference numerals are used for the same members as Figs. 4 and 5.

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

After forming an insulating film made of an oxide on the top of the resultant P-MOS transistor 120 is formed, an opening 147 for exposing the top of one side of the source 110 and the drain 105, respectively, using a photolithography method. Form them. Subsequently, a first metal layer 135 made of titanium, titanium nitride, tungsten, nitride, or the like is deposited on the resultant product on which the openings 147 are formed, and then 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 first anchor 171 supporting the support layer 170.

The first passivation layer 140 is formed on the first metal layer 135 and the substrate 101. The first passivation layer 140 is formed of a silicate glass (PSG) to have a thickness of about 8000 kPa using a chemical vapor deposition (CVD) method. The first protective layer 140 prevents damage to the substrate 101 in which the P-MOS 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 forms a titanium layer having a thickness of about 300 kW using a sputtering method of titanium, and then uses titanium nitride on the titanium layer at about 1200 kW using a physical vapor deposition method (PVD). It is completed by forming a titanium nitride layer in thickness. Since the light incident from the light source (not shown) is incident on the second metal layer 145 not only to the mirror 260 but also to a portion other than the portion covered by the mirror 260, a light leakage current is generated in the active matrix 100. (photo leakage current) flows to prevent the device from malfunctioning. Subsequently, a portion of the second metal layer 145 in which the via hole 270 is to be formed in a subsequent process, that is, a portion in which the drain pad of the first metal layer 135 is formed is etched into the second metal layer 145. Form a hole (not shown).

The second passivation layer 150 is formed on the second metal layer 145. The second protective layer 150 is formed of a silicate glass (PSG) having a thickness of about 2000 kPa using a chemical vapor deposition method. 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 formed on the second passivation layer 150. The etch stop layer 155 prevents the second passivation layer 150 and the products on 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. by using a low pressure chemical vapor deposition (LPCVD) method, thereby forming the substrate 101 and the first metal layer 135. The active matrix 100 including the first protective layer 140, the second metal layer 145, the second protective layer 150, and the etch stop layer 155 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 first anchor supporting the support layer 170 formed later by etching the portion of the second metal layer 145 formed below and the portions adjacent to both sides thereof by etching to expose a portion of the etch stop layer 155. 171 and the second anchors 172a, 172b make a position to be formed. Accordingly, the etch stop layer 155 is exposed in the shape of three squares spaced apart by a predetermined distance. Then, the first photoresist is removed.

Referring to FIG. 6C, the first layer 169 is stacked on top of the etch stop layer 155 and the first sacrificial layer 160 exposed in three quadrangles as described above. The first layer 169 is formed to have a thickness of about 0.1 to 1.0 μm using a low pressure chemical vapor deposition (LPCVD) method of a hard material such as nitride or metal. The first layer 169 is later patterned with a support element 175, which supports a support layer 170 for supporting the actuator 210, a support line 174 for supporting the common electrode line 240, and The first anchor 171 and the second anchors 172a and 172b supporting the support layer 170 may be formed. In this case, a portion of the first layer 169 attached to the etch stop layer 155 of the center among the portions attached to the etch stop layer 155 exposed to the three quadrangles becomes the first anchor 171, Portions attached to both sides of the etch stop layer 155 may be second anchors 172a and 172b.

The lower electrode layer 179 is stacked on top of the first layer 179. The lower electrode layer 179 is formed of a metal having electrical conductivity such as platinum, tantalum, or platinum-tantalum (Pt-Ta) to have a thickness of about 0.1 to 1.0 μm using a sputtering method or a chemical vapor deposition method. The lower electrode layer 179 is later applied with a first signal (image signal) from the outside, and is patterned into a lower electrode 180 having a mirror-shaped 'c' shape in which protrusions are formed toward the first anchor 171.

A second layer 189 made of a piezoelectric material such as PZT or PLZT is stacked on the lower electrode layer 179. The second layer 189 is formed to have a thickness of about 0.1 to 1.0 μm using a sol-gel method, sputtering method, spin coating method, or chemical vapor deposition method. Preferably, the second layer 189 is formed by spin coating PZT prepared by the sol-gel method to have a thickness of about 0.4 μm. Subsequently, the piezoelectric material constituting the second layer 189 is subjected to heat treatment by a rapid heat treatment (RTA) method to perform phase change. The second layer 189 is later formed with the first strained layer 190 and the second upper electrode 210 and the lower portion which are deformed by a first electric field generated between the first upper electrode 200 and the lower electrode 180. It is patterned into a second strained layer 191 causing strain by a second electric field generated between the electrodes 180.

The upper electrode layer 199 is formed on the second layer 189. The upper electrode layer 199 may have a thickness of about 0.1 to 1.0 μm of a metal having electrical conductivity such as platinum, tantalum, silver (Ag), aluminum (Al), or platinum-tantalum by chemical vapor deposition or sputtering. Form. The upper electrode layer 199 is patterned into first and second upper electrodes 200 and 201, each having a rectangular flat plate shape and spaced apart from each other by a predetermined distance.

Referring to FIG. 6D, after applying and patterning a second photoresist (not shown) on the upper electrode layer 199, the upper electrode layer 199 is patterned using the second photoresist as a mask. Each of the first upper electrode 200 and the second upper electrode 201 having the shape of a rectangular flat plate and being spaced apart from each other by a predetermined distance are formed side by side. Second signals (bias signals) are respectively applied to the first and second upper electrodes 200 and 201 through the common electrode line 240 formed later.

Subsequently, the second layer 189 is patterned in the same manner as the patterning of the upper electrode layer 199 to form a rectangular flat plate, and the first deformable layer 190 and the first sidewall are formed to be spaced apart from each other by a predetermined distance. 2 strain layer 191 is formed. In this case, the first and second strained layers 190 and 191 have a larger area than the first and second upper electrodes 200 and 201, respectively. The first strained layer 190 is deformed by a first electric field generated by a potential difference between the first upper electrode 200 and the lower electrode 180, and the second strained layer 191 is formed by the second upper electrode ( Deformation is caused by the second electric field generated by the potential difference between 201 and the lower electrode 180.

Subsequently, the lower electrode layer 179 is patterned by the above-described method so that the protrusions are stepped toward the first anchor 171 (that is, toward the direction where the hole of the second metal layer 145 is formed below). A lower electrode 180 having a mirror shaped 'c' shape is formed.

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 two arms of the mirror-shaped 'c'-shaped lower electrode 180 have a slightly larger area than the first and second deformable layers 190 and 191, respectively, and the common electrode line 240 is formed after the support line ( The upper portion 174 is spaced apart from the lower electrode 180 by a predetermined distance. Accordingly, 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, 172b. . At this time, both sides of the portion of the first layer 169 that contacts the etch stop layer 155 exposed in the three quadrangles are second anchors 172a and 172b, and the center portion of the first anchor 171 is do. The first anchor 171 and the second anchors 172a and 172b each have a rectangular box shape, and a hole of the second metal layer 145 and a hole of the first metal layer 135 are disposed below the first anchor 171. A drain pad is formed.

The support layer 170 has a shape of a rectangular ring wider than the lower electrode 180 and is integrally formed with the support line 174. In this state, when the first sacrificial layer 160 is later removed, a supporting element 175 having a shape as shown in FIG. 4 is formed. That is, the support layer 170 has a rectangular ring shape and is formed at one side of the support line 174 along a direction orthogonal to the support line 174 on the same plane, and supports the rectangular support layer 170 among the rectangular ring shapes. A first anchor 171 is formed integrally with the two arms and is attached to the etch stop layer 155 at a lower portion between the two arms horizontally extending in a direction orthogonal to the line 174. Two second anchors 172a and 172b are formed integrally with the two arms, respectively, and attached to the etch stop layer 155 at an outer lower portion. The first anchor 171 and the second anchors 172a and 172b which together support the support layer 170 are formed under a portion of the support layer 170 adjacent to the support line 174. In addition, protrusions of the lower electrode 180 are formed in a step shape from the lower electrode 180 around the first anchor 171 toward the first anchor 171.

The lower electrode 180 is formed on an upper portion of two arms horizontally extending in a direction orthogonal to the support line 174 of the support layer 170. Accordingly, the first anchor 171 is formed between the mirror-shaped 'c' shaped lower electrodes 180, and the second anchors 172a and 172b are formed outside the lower electrode 180, respectively.

Subsequently, a third photoresist (not shown) is applied and patterned on top of the support element 175 and the actuator 210 to form the first and first layers from the common electrode line 240 formed on the support line 174. 2 A portion of the upper electrodes 200 and 201 are exposed. At this time, even the protrusions of the lower electrode 180 are exposed together from the first anchor 171.

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

Subsequently, the first anchor 171, the etch stop layer 155, and the first anchor 171 are formed from an upper portion 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 formed below. 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 lower electrode 180 is formed from the inside of the via hole 270 and the via hole 270. The via contact 280 is formed up to the protrusions of the. At the same time, as shown in FIG. 4, the first upper electrode connecting member 230 from the first upper electrode 200 to the common electrode line 240 through a portion of the first insulating layer 230 and the support layer 170. The second upper electrode connecting member 231 is formed from the second upper electrode 201 to the common electrode line 240 through a portion of the second insulating layer 231 and the support layer 170.

The via contact 280 and the first and second upper electrode connection members 230 and 231 are each deposited with platinum or platinum-tantalum to have a thickness of about 0.1 to 0.2 μm using a sputtering method or a chemical vapor deposition method. 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. The lower electrode 180 is connected to the drain pad of the first metal layer 135 through the protrusions and the via contact 280.

Subsequently, ends of the first and second upper electrodes 200 and 201 formed on the two arms of the rectangular ring-shaped support layer 170, that is, the upper and lower upper electrode connecting members 230, The first and second upper electrodes 200 and 201, the first and second strained layers 190 and 191, the lower electrode 180, and the support layer 170 are etched from the portion facing the 231 to thereby form a first portion. The first etching hole 290 penetrating the end of one of the two arms of the support layer 170 from the upper electrode 200 and the other one of the two arms of the support layer 170 from the second upper electrode 201. A second etching hole 291 penetrating the end is formed. The first and second etching holes 290 and 291 are formed to be positioned on the same straight line as the post 250 which is formed later, respectively. In consideration of the size of the actuator 210, preferably, the first etching hole 290 and the second etching hole 291 are each formed to have a diameter of about 2 μm. In the present invention, as described above, after the actuator 210 is completed, the first and second etching holes 290 and 291 are formed, but the first and second etching holes 290 and 291 are the actuator 210. Patterning each of the layers constituting the first and second upper electrodes 200 and 201, the first and second strained layers 190 and 191, and the lower electrode 180 and the support layer 170, respectively. When doing this, it can also form simultaneously.

Referring to FIG. 6E, a fourth photoresist is applied on the actuator 210 and the support element 175 by spin coating to form a second sacrificial layer 300. The second sacrificial layer 300 is formed to have a sufficient height so as to completely cover the actuator 210. Subsequently, the second sacrificial layer 300 is patterned to form the post 250 and the mirror 260, thereby forming the first and second upper electrodes 200, 200, of the '-' shaped lower electrode 180. A portion of the portion 201 that is not formed (that is, a portion of the portion spaced parallel to the common electrode line 240) is exposed. Subsequently, a metal such as aluminum (Al) having excellent reflectivity is deposited on the second sacrificial layer 300 using a sputtering method or a chemical vapor deposition method, and the deposited metal is patterned to have a rectangular plate shape. The mirror 260 and the post 250 supporting the mirror 260 are simultaneously formed.

Subsequently, the second sacrificial layer 300 and the first sacrificial layer 160 are removed using xenon fluoride (XeF ₂ ) or bromine fluoride (BrF ₂ ). During removal of the first and second sacrificial layers 160 and 300, the xenon fluoride or bromide fluoride vapor is supported through the first and second etching holes 290 and 291 as well as the periphery of the actuator 210. Since the lower portion of the support layer 170 also penetrates simultaneously, the first sacrificial layer 160 under the support layer 170 may be easily removed.

As such, when the first and second sacrificial layers 160 and 300 are removed, a second air gap 310 is formed at the position of the second sacrificial layer 300, and the first sacrificial layer 160 is positioned at the position of the first sacrificial layer 160. An air gap 165 is formed. Then, washing and drying are performed to complete the AMA device as shown in FIG.

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 of the first metal layer 120, and the via contact 280. The common electrode wire 240 and the first and second upper electrode connecting members 230 and 231 are respectively applied to the lower electrode 180 through the first electrode and the second upper electrode 200 and 201. The second signal is applied through. Therefore, a first electric field is generated between the first upper electrode 200 and the lower electrode 180 according to the potential difference, and a second electric field is generated between the second upper electrode 201 and the lower electrode 180 according to the potential difference. do. The first strained layer 190 between the first upper electrode 200 and the lower electrode 180 causes deformation by the first electric field, and simultaneously the second upper electrode 201 and the lower electrode by the second electric field. The second strained layer 191 between the 180 causes deformation.

As the first and second strained layers 190 and 191 contract in a direction orthogonal to the first and second electric fields, respectively, the actuator 210 including the first and second strained layers 190 and 191 may be formed. It is bent at a predetermined angle. 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.

According to the manufacturing method of the thin film type optical path control device according to the present invention, the first and second etching holes are formed to penetrate the support layer from the first and second upper electrodes on both sides of the post, respectively, and the first and the same time as the outer part of the actuator. By etching the sacrificial layer through the second etching hole, the supporting layer may be prevented from adhering to the etch stop layer to prevent the actuator from sticking to the active matrix, thereby preventing the point defect of the pixel.

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 (6)

An active matrix (100) containing a first metal layer (135) having a MOS transistor (120) embedded therein and having a drain pad extending from the drain (105) of the transistor (120); Iii) a support line 174 formed on the active matrix 100, ii) a support layer 170 integrally formed with the support line 174 and having a rectangular ring shape, and iii) the support layer 170 A first anchor 171 and second anchors 172a and 172b respectively contacting the active matrix 100 below the portion adjacent to the support line 174 to support the support layer 170. Means 175; A lower electrode 180 formed on the support layer 170, a first strained layer 190 formed on one side of the lower electrode 180, and a second strained layer formed on the other side of the lower electrode 180 ( 191, an actuator 210 including a first upper electrode 200 formed on the first strained layer 190, and a second upper electrode 201 formed on the second strained layer 191. ; A plurality of etching holes formed through the first and second deforming layers 190 and 191, the lower electrode 180, and the support layer 170 from one side of the first and second upper electrodes 200 and 201, respectively. 290, 291); And Thin film type optical path control device, characterized in that it comprises a mirror formed on top of the actuator (210). The method of claim 1, wherein the first upper electrode 200 is formed on an upper portion of one arm formed in a direction perpendicular to the support line 174 of the support layer 170 having the shape of the square ring. The upper electrode 201 is formed on the other arm formed in a direction perpendicular to the support line 174 of the support layer 170 having the shape of the square ring, and is formed on the first upper electrode 200. A first etching hole 290 is formed by penetrating one arm of the support layer 170 from one side, and penetrates another arm of the support layer 170 from one side of the second upper electrode 201. A thin film type optical path adjusting device, characterized in that two etching holes (291) are formed. The apparatus of claim 2, wherein the first etching hole (290) and the second etching hole (291) each have a diameter of about 2 μm. 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 sacrificial layer on the active matrix; Forming a first layer, a lower electrode layer, a second layer, and an upper electrode layer on the first sacrificial layer; Patterning the upper electrode layer, the second layer and the lower electrode layer to form an actuator including a first upper electrode, a second upper electrode, a first strained layer, a second strained layer, and a lower electrode; Patterning the first layer to form a support line comprising a support line, a support layer and first and second anchors; Forming a plurality of etching holes penetrating the support layer from one side of the first upper electrode and the second upper electrode, respectively; And And forming a mirror after forming a second sacrificial layer on an upper portion of the actuator. The method of claim 4, wherein the forming of the support means comprises: forming a support line on the active matrix, forming a support layer having a rectangular ring shape integrally with the support line, and And forming first and second anchors respectively in contact with the active matrix under the portion adjacent to the support line to support the support layer, wherein forming the etching hole comprises: Forming a first etching hole through one arm formed in a direction perpendicular to the support line among the support layers having the shape of the square ring from one side, and forming the shape of the square ring from one side of the second upper electrode. A second layer penetrating the other arm of the support layer formed in a direction perpendicular to the support line; Method for manufacturing a thin-film optical path control device comprising the steps of forming a hole called. The method of claim 5, wherein the forming of the mirror comprises: placing the mirror on the same line as the first etching hole and the second etching hole on a portion formed in parallel with the support line in the support layer having the shape of the square ring. A method of manufacturing a thin film optical path control device, characterized in that it is carried out after the step of forming a post.