KR19990019659A - Thin film type optical path control device and its manufacturing method - Google Patents

Abstract

According to an embodiment of the present invention, a protective layer and a protective layer are formed on an upper portion of a driving substrate in which MxN transistors (not shown) corresponding to MxN (M and N are integers) pixels are formed in a matrix form. An etch stop layer that prevents damage to the protective layer and its lower portion during subsequent processing and a bridge that is connected to neighboring pixels in a row (or column) direction for each pixel on the top of the etch stop layer, wherein the region adjacent to the bridge is etched. The other region, which is in contact with the barrier layer and extends from the bridge, is formed through a membrane formed at a predetermined distance from the etch barrier layer and an adjacent pixel and an insulator on the top of the membrane to receive an image signal from a transistor for each pixel. The insulating layer is formed on the upper portion of the strained layer and the strained layer is deformed in proportion to the size of the electric field. Each pixel and the upper electrode are formed to connect with the neighboring pixels in the row (or column) direction and a connection layer formed on top of the insulation and the top of the upper electrode.

Description

Thin film type optical path control device and its manufacturing method

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film type optical path adjusting device and a method of manufacturing the same. In particular, cracks may be prevented in the strained layer and the upper electrode due to the step difference between the insulating windows formed on the bridge of the actuator. A thin-film optical path control device and its manufacturing method.

In general, a spatial light modulator, which is an apparatus for projecting optical energy onto a screen, may be variously applied to optical communication, image processing, and information display apparatus. Such devices are classified into a direct view type image display device and a projection type image display device according to a method of projecting a light beam incident from a light source onto a screen. The direct view image display device includes a CRT (Cathod Ray Tube), and the projection image display device includes a liquid crystal display (hereinafter referred to as an LCD), a DMD (deformable mirror device), or an AMA (Actuated). Mirror Arrays).

The above-described CRT apparatus is an excellent display apparatus which is guaranteed an average brightness of 100 ft-L (white display) or more, a contrast ratio of 30: 1 or more, a lifetime of 10,000 hours or more. However, since the CRT has a large weight and volume and maintains high mechanical strength, it is difficult to make the screen completely flat, which causes distortion of the peripheral part. In addition, since CRTs excite phosphors with an electron beam to emit light, there is a problem that a high voltage is required to produce an image.

Therefore, LCDs have been developed to solve the above-mentioned problems of CRT. The advantages of such LCDs are explained in comparison with CRTs. LCDs operate at low voltages, consume less power, and provide images without distortion.

However, despite the above-mentioned advantages, the LCD has a low light efficiency of 1 to 2% due to the polarization of the light beam, and there is a problem that the response speed of the liquid crystal material therein is slow.

Accordingly, in order to solve the problems of the LCD as described above, a device such as a DMD or an AMA has been developed. Currently, AMA can achieve a light efficiency of 10% or more, while DMD has a light efficiency of about 5%. In addition, the AMA is not only affected by the polarity of the incident luminous flux but also does not affect the polarity of the luminous flux.

Typically, the respective actuators formed inside the AMA cause deformation depending on the electric field generated by the applied image signal and bias voltage. When this actuator causes deformation, each of the mirrors mounted on top of the actuator is inclined in proportion to the magnitude of the electric field.

Thus, these inclined mirrors can reflect light incident from the light source at a predetermined angle. Piezoelectric ceramics such as PZT (Pb (Zr, Ti) O ₃ ), or PLZT ((Pb, La) (Zr, Ti) O ₃ ) are used as a constituent material of the actuator for driving the respective mirrors. As the constituent material of this actuator, electrodistorted ceramics such as PMN (Pb (Mg, Nb) O ₃ ) can be used.

The AMA is classified into a bulk type and a thin film type. Currently, AMA is the main trend of the thin-film optical path control device.

1 is a plan view of a conventional thin film type optical path control device.

Referring to FIG. 1, one side of the actuator 130 has a concave portion having a rectangular shape at a center thereof, and the concave portion is formed in a stepped shape toward both edges. The other side of the actuator 130 has a rectangular protrusion which narrows down stepwise toward the center portion corresponding to the concave portion. Therefore, the concave portion of the actuator 130 is fitted with a rectangular protrusion of the adjacent actuator, and the rectangular protrusion is fitted with the concave portion of the adjacent actuator.

The actuator 130 is divided into a driver 150 and a bridge 170. The driving unit 150 is formed to be spaced apart from the etch stop layer 40 of the driving substrate 10 shown in FIG. 2 by a predetermined distance, and is deformed when an image signal is applied to change the path of the light beam incident through the optical system to the slit. Reflect. At this time, the amount of luminous flux passing through the slit is changed according to the angle at which the driving unit 150 is deformed to implement various color screens.

The bridge 170 connects neighboring pixels in a row (or column) direction for each pixel. The bridge 170 is in contact with the etch stop layer 40 of the driving substrate 10 shown in FIG. 2, and the driving unit 150 extending from the bridge 170 is formed to be spaced apart from the etch stop layer 40 by a predetermined distance. Accordingly, the bridge 170 allows the driving unit 150 to operate stably when an image signal is applied. In addition, an insulating window 140 is formed at a predetermined portion of the bridge 170 to electrically separate the neighboring actuator.

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

Referring to FIG. 2, the thin film type optical path control apparatus includes a driving substrate 10 having a drain 20 formed on one side thereof, and an actuator 130 formed thereon.

M × N (M, N is an integer) transistors are built in a matrix form in the driving substrate 130. In addition, the driving substrate 10 includes a protective layer 30 formed on the upper portion and the drain 20 and an etch stop layer 40 formed on the upper portion.

The actuator 130 has a membrane formed on one side of the etch stop layer 40 in contact with the portion where the drain 20 is formed and the other side thereof is parallel to the etch stop layer 40 via an air gap 50. membrane: 60, the lower electrode 70 formed on the membrane 60, the strained layer 80 formed on the lower electrode 70, and the upper electrode 90 formed on the strained layer 80. ), The stripe 100 formed on a predetermined portion of the upper electrode 90, and the lower electrode 70, the membrane 60, the etch stop layer 40, and the protective layer 30 from the other side of the strained layer 80. The distribution hole 110 vertically formed to the drain 20 through the lower electrode 70 and the lower electrode 70 and the power distribution unit 120 is formed so that the drain electrode 20 is electrically connected to each other.

3 is a cross-sectional view of the apparatus shown in FIG. 1 taken along line B-B '.

Referring to FIG. 3, the bridge 170 may include a driving substrate 10, a protection layer 30 formed on the driving substrate 10, an etch stop layer 40 formed on the protection layer 30, The membrane 60 formed on the etch stop layer 40, the lower electrode 70 formed on the membrane 60, the insulating window 140 formed by removing a predetermined portion of the lower electrode 70, and the lower part thereof. And a strained layer 80 formed on the electrode 70 and the insulating window 140, and an upper electrode 90 formed on the strained layer 80.

The insulating window 140 in which the predetermined portion of the lower electrode 70 is removed from the bridge 170 is electrically separated from the actuator 130 and the neighboring actuator to provide a separate image signal from the transistor. Therefore, each actuator 130 is driven independently since the image signal is provided separately.

However, the conventional thin film type optical path adjusting device has a problem that cracks occur in the strained layer and the upper electrode due to a step generated by an insulating window electrically separating the neighboring actuators to provide individual image signals for each pixel.

The present invention has been made to solve the conventional problems as described above, an object of the present invention is to form an insulating portion inside the insulating window to remove the step by removing the cracks generated in the strained layer and the upper electrode It is an object of the present invention to provide an optical path control device and a method of manufacturing the same.

In order to achieve the above object, the present invention provides an M x N transistor (not shown) corresponding to M x N (M, N is an integer) formed on the driving substrate in which the matrix is embedded. A bridge formed on the passivation layer and the upper portion of the passivation layer to prevent damage to the passivation layer and the lower portion of the passivation layer during the subsequent process, and a bridge connected to neighboring pixels in the row (or column) direction on each pixel on the etch stop layer. The region adjacent to the bridge is in contact with the etch stop layer, and the other region extending from the bridge is formed through the membrane formed by being spaced apart from the etch stop layer by a predetermined distance, and the pixel and the insulating part adjacent to the upper part of the membrane, and the image from the transistor for each pixel. It is formed in the upper part of the lower electrode and the lower electrode receiving the signal through an insulating part and is deformed in proportion to the magnitude of the electric field. And a connection layer formed on the upper portion of the upper-layer and the strain layer the upper electrode and the upper insulating portion for connection with the neighboring pixels in the row (or column) direction for the upper electrode and the pixel which is formed by sandwiching the insulation on.

The above objects and various advantages of the present invention will become more apparent from the preferred embodiments of the invention described below by those skilled in the art.

1 is a plan view of a conventional thin film type optical path control device,

FIG. 2 is a cross-sectional view taken along line AA ′ of the apparatus of FIG. 1; FIG.

3 is a cross-sectional view taken along line B-B 'of the apparatus of FIG.

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

FIG. 5 is a cross-sectional view of the device of FIG. 4 taken along line C-C '; FIG.

6 is a cross-sectional view taken along line D-D 'of the apparatus of FIG. 5;

7A to 7C are manufacturing process diagrams of the apparatus shown in FIG. 6.

* Explanation of symbols for main parts of the drawings

510: driving substrate 530: protective layer

540: etch stop layer 560: membrane

570: lower electrode 580: strained layer

590: upper electrode 640: insulating window

645: insulation 650: drive

660: connection layer 670: bridge

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

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

Referring to FIG. 4, one side of the actuator 630 has a concave portion having a rectangular shape at a center thereof, and the concave portion is formed to have a stepped shape toward both edges. The other side of the actuator 630 has a rectangular protrusion that narrows stepwise toward the center portion corresponding to the concave portion. Therefore, the concave portion of the actuator 630 is fitted with the rectangular protrusion of the adjacent actuator, and the rectangular protrusion is fitted with the concave portion of the adjacent actuator.

The actuator 630 is divided into a driver 650 and a bridge 670. The driving unit 650 is formed to be spaced apart from the etch stop layer 540 of the driving substrate 510 of FIG. 5 by a predetermined distance, and is deformed when an image signal is applied to change the path of the light beam incident through the optical system to reflect the slit. do. At this time, the amount of luminous flux passing through the slit is changed according to the angle at which the driving unit 650 is deformed to implement various color screens.

The bridge 670 is connected to neighboring pixels in a row (or column) direction for each pixel. The bridge 670 is in contact with the etch stop layer 540 of the driving substrate 510, and the driving unit 650 extending from the bridge 670 is formed to be spaced apart from the etch stop layer 540 by a predetermined distance. Accordingly, the bridge 670 allows the driving unit 650 to operate stably when an image signal is applied. In addition, an insulating window 640 is formed in a predetermined portion of the bridge 670 vertically from the upper electrode 590 on the bridge 670 to the top of the membrane 560 so as to be electrically separated from neighboring actuators. The insulating part 645 is formed of an insulating material such as silicon oxide in the insulating window 640. Since the step generated by the insulating window 640 is removed through the insulating part 645, cracks do not occur in the deformation layer 580 and the upper electrode 590.

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

Referring to FIG. 5, the thin film type optical path control apparatus includes a driving substrate 510 having a drain 520 formed on one side thereof, and an actuator 630 formed thereon.

Inside the driving substrate 510, M × N transistors (M and N are integers) are built in a matrix. In addition, the driving substrate 510 has a protective layer 530 and an etch stop layer 540 sequentially formed on the top and the drain 520.

The actuator 630 may have a membrane 560 formed to be in contact with a portion of the etch stop layer 540 formed at a lower portion thereof and to be parallel to the etch stop layer 540 through the air gap 550. The lower electrode 570 formed on the membrane 560, the strained layer 580 formed on the lower electrode 570, the upper electrode 590 formed on one side of the strained layer 580, and the upper portion The strip 600 formed on a predetermined portion of the electrode 590 and the drain 520 through the lower electrode 570, the membrane 560, the etch stop layer 540, and the protective layer 530 from the other side of the strained layer 580. The distribution hole 610 formed up to) and the lower electrode 570 and the drain 520 in the distribution hole 610 are formed to be electrically connected to each other.

FIG. 6 is a cross-sectional view of the apparatus shown in FIG. 4 taken along the line D-D '.

Referring to FIG. 6, the bridge 670 may include a driving substrate 510, a protective layer 530 formed on the driving substrate 510, an etch stop layer 540 formed on the protective layer 530, The membrane 560 formed on the etch stop layer 540, the lower electrode 570 formed on the membrane 560, the strained layer 580 formed on the lower electrode 570, and the strained layer 580. The upper electrode 590 formed on the upper part of the upper part, the insulating window 640 vertically formed from the upper electrode 590 to the upper part of the membrane 560, and the insulating part 645 formed filling the inside of the insulating window 640. And a connection layer 660 that connects the insulating window 640 and the upper electrode 590 electrically separated by the insulating part 645.

7A to 7C are manufacturing process diagrams of the apparatus shown in FIG. 6.

Referring to FIG. 7A, the driving substrate 510 includes M × N transistors (not shown) where M is an integer, and is formed in a matrix form.

The protective layer 530 is formed on the driving substrate 510 by using a chemical vapor deposition method of the silicate glass. The protective layer 530 is formed to a thickness of about 0.1 to 1.0 μm. The protective layer 530 prevents the driving substrate 510 containing the transistor from being damaged during the subsequent process.

The etch stop layer 540 is formed on the passivation layer 530. The etch stop layer 540 is formed by low pressure chemical vapor deposition (LPCVD). The etch stop layer 540 is formed to a thickness of 1000 ~ 2000Å. The etch stop layer 540 prevents the protective layer 530 and its bottom from being damaged during the subsequent etch process.

The membrane material layer 560 ′ is stacked on the etch stop layer 540. The membrane material layer 560 'is formed by low pressure chemical vapor deposition. The membrane material layer 560 'is formed to a thickness of 0.1 to 1.0 mu m.

The lower electrode material layer 570 ′ is stacked on the membrane material layer 560 ′. The lower electrode material layer 570 ′ is formed to have a thickness of about 1000 to 1200 Å by sputtering a metal having excellent electrical conductivity such as platinum or platinum-tantalum.

A strained material layer 580 ′ is formed on the lower electrode material layer 570 ′ with a piezoelectric material such as PZT or PLZT. The deformable material layer 580 ′ is formed to have a thickness of 0.1 μm to 1.0 μm by a sol-gel method, a sputtering method, or a chemical vapor deposition method. Subsequently, the strained material layer 580 ′ is subjected to rapid thermal treatment (RAT) for phase transformation.

The upper electrode material layer 590 'is formed on the deformable material layer 580' of a metal having excellent electrical conductivity and reflective properties, for example, aluminum, platinum, or silver. The upper electrode material layer 590 'is formed by a sputtering method.

Referring to FIG. 7B, an insulating window 640 is formed by vertically removing the strained material layer 580 ′ and the lower electrode material layer 570 ′ from a predetermined portion of the upper electrode material layer 590 ′. The insulating window 640 electrically separates the neighboring actuators so that the actuators 630 of each pixel are driven independently of individual image signals. In this case, the insulating window 640 is formed to expose the membrane material layer 560 ′.

Referring to FIG. 7C, an insulating part 645 is formed by filling an inside of the insulating window 640 with an insulating material such as silicon oxide. The insulating portion 645 is formed from the top of the exposed membrane material layer 560 'to the top of the upper electrode material layer 590'.

Accordingly, the insulation unit 645 may prevent the cracks from occurring in the strained layer 580 and the upper electrode 590 to be described later by removing the step generated by the insulation window 640.

In this case, the upper electrode material layer 590 ′ is electrically separated from neighboring actuators by the insulating window 640 and the insulating part 645. However, since the upper electrode 590 is a common electrode, it must be electrically connected to neighboring actuators.

Therefore, the connection layer 660 is formed on the upper electrode material layer 590 electrically separated by the insulating window 640 and the insulating part 645. The connection layer 660 is formed by a method of lifting off platinum, which is a material having excellent electrical conductivity.

Lastly, the upper electrode material layer 590 ', the modifying material layer 580', the lower electrode material layer 570 ', and the membrane material layer 560 are patterned in pixel units to form the upper electrode 590 and the modifying layer ( 580, the lower electrode 570, and the membrane 560 are formed.

As described above, the thin film type optical path adjusting device according to the present invention forms an insulating window from the upper electrode to the upper part of the membrane and then fills the inside with an insulating material to remove the step, so that the cracks are generated due to the step between the strained layer and the upper electrode. There is an effect that can be prevented.

As described above, although the present invention has been described with reference to the drawings, those skilled in the art may variously modify and change the present invention without departing from the spirit and scope of the invention as set forth in the claims below. I can understand that you can.

Claims (7)

The protective layer 530 and the protective layer formed on the driving substrate 510 in which M × N transistors (not shown) corresponding to M × N (M and N are integers) pixels are formed in a matrix form. An etch stop layer 530 formed on an upper portion of the 530 to prevent damage to the protective layer 530 and its lower portion during a subsequent process, and a row (or column) direction for each pixel on the etch stop layer 530 And a bridge 670 connected to a neighboring pixel, and an area adjacent to the bridge 670 is in contact with the etch stop layer 540, and another area extending from the bridge 670 is the etch stop layer 670. ) And a lower electrode 570 formed through a membrane 560 spaced apart from each other by a predetermined distance and a pixel adjacent to an upper portion of the membrane 560 and an insulating part 645 to receive an image signal from the transistor for each pixel. And an image of the lower electrode 570 The deformable layer 580 formed through the insulating part 645 and deformed in proportion to the size of the electric field, and the upper electrode formed through the insulating part 645 on the deformable layer 580. 590 and a thin film type optical path adjusting device including a connection layer 660 formed on the upper portion of the insulating portion 645 and the upper electrode 590 so as to be connected to neighboring pixels in a row (or column) direction for each pixel. . The thin film type optical path adjusting device according to claim 1, wherein the insulating portion (645) is formed of an insulating material such as silicon oxide. The thin film type optical path control device according to claim 1, wherein the connection layer (660) is formed of a material such as platinum having excellent electrical conductivity. Sacrifice to have a pattern for exposing a portion of the driving substrate 510 for each pixel on the driving substrate 510 having a transistor, a protective layer 530 protecting the upper portion thereof, and an etch stop layer 540 at the top thereof. Forming a layer (not shown) and a membrane material layer 560 ', a lower electrode material layer 570', a strain material layer 580 'and an upper portion of the sacrificial layer and the exposed driving substrate 510. The electrode material layer 590 'is sequentially stacked, and a portion of the upper electrode material layer 590' is removed from a region in which a bridge 670 is formed to connect neighboring pixels along a row (or column) direction. Forming an insulating window 640 and filling the inside of the insulating window 640 with an insulating material to form an insulating part 645 and electrically by the insulating window 640 and the insulating part 645. A connection layer 640 is formed to electrically connect the separated upper electrode material layer 590 '. And patterning the upper electrode material layer 590 ', the strain material layer 580', the lower electrode material layer 570 ', and the membrane material layer 560' in pixel units. ), Forming the deformable layer (580), the lower electrode (570), the membrane (560). The method of manufacturing a thin film type optical path control device according to claim 4, wherein the insulating portion (645) is formed of an insulating material such as silicon oxide. The method of manufacturing a thin film type optical path control device according to claim 4, wherein the connection layer (660) is formed of a material having excellent electrical conductivity such as platinum. 8. A method according to claim 4 or 7, wherein the connection layer (660) is formed by a lift off method.