KR19990005302A - Manufacturing method of thin film type optical path control device - Google Patents

Abstract

The present invention is characterized in that it comprises sequentially forming a protective layer, an etching prevention layer, a membrane and a lower electrode on a driving substrate on which M × N (M, N is an integer) transistors (not shown) are embedded in a matrix form, Forming a photoresist on the upper portion of the electrode; forming a diffusing-preventing layer for preventing irregular reflection of ultraviolet light irradiated to the upper portion of the photoresist; and forming a predetermined portion of the photoresist under the diffusing- Exposing a portion of the lower electrode by removing a portion exposed to ultraviolet rays in the photoresist; and removing the exposed portion of the lower electrode Removing the photoresist formed on the upper portion of the lower electrode, And an insulating includes forming sequentially the strained layer and the upper electrode on the top of the window.

Description

Manufacturing method of thin film type optical path control device

The present invention relates to a manufacturing method of a thin film type optical path adjusting device and more particularly to a thin film type optical path adjusting device capable of preventing a crack from being generated in an upper electrode formed on an upper part of an insulating window, And a manufacturing method of the apparatus.

2. Description of the Related Art Generally, a spatial light modulator, which is an apparatus for projecting optical energy onto a screen, can be variously applied to optical communication, image processing, and information display devices. These 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 on a screen. Examples of the direct-view type image display device include a CRT (Cathod Ray Tube), and the projection type image display device includes a liquid crystal display (LCD), a DMD (Deformable Mirror Device), or an AMA Mirror Arrays).

The CRT device described above is an excellent display device with a luminance of at least 100 ft-L (white display), a contrast ratio of 30: 1 or more, and a lifetime of 10,000 hours or more. However, since the CRT has a large weight and a large volume and maintains high mechanical strength, it is difficult to make the screen a perfect flat surface, and the peripheral portion is distorted. Further, since the CRT emits light by exciting the phosphor with an electron beam, there is a problem that a high voltage is required to make an image.

Therefore, an LCD has been developed to solve the problems of the CRT described above. The advantages of such a LCD are described below in comparison with a CRT. The LCD operates at a low voltage, consumes less power and provides a distortion-free image.

However, despite the advantages described above, the LCD has a low optical efficiency of 1 to 2% due to the polarization of the light beam, and 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. At present, AMA has a light efficiency of 10% or more compared to DMD having a light efficiency of about 5%. In addition, the AMA is not affected by the polarity of the incident light beam, nor does it affect the polarity of the light beam.

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

Accordingly, the 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 constituent materials of the actuators for driving the respective mirrors. As the constituent material of the actuator, an electrostriction ceramic such as PMN (Pb (Mg, Nb) O ₃ ) can be used.

The AMA described above is divided into a bulk type and a thin film type. At present, AMA is the main trend of thin film type optical path control device.

1 is a plan view of a conventional thin film type optical path adjusting apparatus.

Referring to FIG. 1, the thin film type optical path adjusting apparatus is composed of an actuator 130 and a bridge 170.

One side of the actuator 130 has a rectangular concave portion at its central portion, and the concave portion is formed into a shape widening stepwise toward both edges. The other side of the actuator 130 has a rectangular protruding portion corresponding to the concave portion and narrowing stepwise toward the center portion. Therefore, the rectangular protrusion of the actuator adjacent to the concave portion of the actuator 130 is fitted, and the rectangular protrusion is fitted into the concave portion of the adjacent actuator.

The bridge 170 connects the actuator 130 and the neighboring actuator in the transverse direction. The actuator 130 operates stably by the bridge 170. In addition, an insulating window 160 is formed at a predetermined portion of the bridge 170 to electrically isolate the neighboring actuator.

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

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

In the driving substrate 130, M × N (M, N is an integer) transistors are embedded in a matrix form. The driving substrate 10 includes a protective layer 30 formed on the driving substrate 10 and the drain 20 and an etching prevention layer 40 formed on the protective layer 30.

The actuator 130 includes a membrane formed such that one side thereof is in contact with a portion where the drain 20 is formed in the lower part of the etching preventing layer 40 and the other side is in parallel with the etching preventing layer 40 via an air gap 50 a lower electrode 70 formed on the upper portion of the membrane 60, a strained layer 80 formed on the upper portion of the lower electrode 70, an upper electrode 90 formed on one side of the strained layer 80, The stripe 100 formed on a predetermined portion of the upper electrode 90 and the drain 20 through the lower electrode 70, the membrane 60, the etching prevention layer 40 and the protection layer 30 from the other side of the strained layer 80 And a power supply 120 formed in the power distribution hole 110 such that the lower electrode 70 and the drain 20 are electrically connected to each other.

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

3, the bridge 170 includes a driving substrate 10, a protection layer 30 formed on the driving substrate 10, an etching prevention layer 40 formed on the protection layer 40, A lower electrode 70 formed on an upper portion of the membrane 60 and a predetermined portion of the lower electrode 70 are removed to form a membrane 60 having a predetermined size d ₄ , A transformer 80 formed on the upper portion of the insulating window 160 and an upper electrode 90 formed on the upper portion of the transformer 80. The insulating window 160, .

4A to 4E are process diagrams of the apparatus shown in Fig. In Figs. 4A to 4E, the same reference numerals are used for the same members as in Fig.

4A, a protection layer 30 made of phosphorous-silicate glass (PSG) is formed on an upper portion of a driving substrate 10 in which M × N (M, N is an integer) .

An etch stop layer 40 made of nitride is formed on the protective layer 30. On the upper side of the protective layer 40, a membrane 60 made of nitride is formed. A lower electrode 70 made of a metal such as platinum (Pt) or tantalum (Ta) is formed on the upper surface of the membrane 60.

Referring to FIG. 4B, a photoresist 140 is applied to the upper portion of the lower electrode 70. A mask 150 for forming an insulating window 160 described later is aligned on the photoresist 140. Then, when the mask 150 is aligned on the photoresist 140, ultraviolet rays are irradiated. At this time, the portions of the photoresist 140 that are multiplexed with the ultraviolet rays by the mask 150 and portions that are not multiplexed are generated. Subsequently, portions of the photoresist 140 that are not multiplexed by ultraviolet rays are removed to expose the lower electrode 70.

Referring to FIG. 4C, the mask 150 over the photoresist 140 is removed. However, in the process of removing the photoresist 140 with an ultraviolet ray, group the width (d ₂₎ that is actually a photoresist 140 is removed it is larger than the width (d ₁₎ which is designed for the photoresist 140 is removed. The reason why the width d _{2 at} which the actual photoresist 140 is removed is formed larger than the width d _{2 at} which the previously designed photoresist 140 is removed is that the mask 150 is not exposed to ultraviolet rays This is because the photoresist 140 also absorbs ultraviolet light and is multiplexed.

Referring to FIG. 4D, the photoresist 140 is removed and the exposed lower electrode 70 is removed to form the insulating window 160. Referring to FIG. Then, the photoresist 140 formed on the lower electrode 70 is removed. At this time, the width of the insulating window 160 is that the width (d ₄₎ formed relative to the actual width (d _3), designed based largely. The reason why the width d ₄ of the insulating window 160 actually formed is larger than the designed width d ₃ is that the width d ₄ from which the actual photoresist 140 is removed is smaller than the designed width d ₃ ).

Referring to FIG. 4E, the strained layer 80 includes a piezoelectric material such as PZT or PZLT on the lower electrode 70 and the insulating window 160 by a sol-gel method, a sputtering method, (CVD) method. Then, the strained layer 80 is phase-changed by a rapid thermal annealing (RTA) method.

An upper electrode (90) is formed on the strained layer (80). The upper electrode 90 is formed of aluminum, platinum, or silver by a sputtering method.

However, since the upper electrode 90 of the conventional thin film type optical path adjusting device is formed such that the width d ₄ of the insulating window 160 formed actually is larger than the width d ₃ of the designed insulating window 160, So that there is a problem in that it is short-circuited.

SUMMARY OF THE INVENTION The present invention has been conceived to solve the above problems, and it is an object of the present invention to provide a method of manufacturing a plasma display panel in which a width of an insulation window is formed to be larger than a designed width, And a method of manufacturing the thin film type optical path adjusting device.

According to an aspect of the present invention, there is provided a method of driving a plasma display panel including a driving substrate on which M × N (M, N is an integer) transistors (not shown) are embedded in a matrix, Forming an anti-glare layer on the upper portion of the lower electrode to prevent irregular reflection of ultraviolet light irradiated on the upper portion of the photoresist; Exposing a predetermined portion of the photoresist to the ultraviolet light; removing a diffuse reflection preventing layer formed on the photoresist; exposing a part of the lower electrode by removing a portion exposed to ultraviolet rays of the photoresist; Forming an insulating window by removing a lower electrode exposed by using a photoresist as a mask; Removing the resist, and sequentially forming a strained layer and an upper electrode on the lower electrode and the insulating window.

The above and other objects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.

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

FIG. 2 is a sectional view taken along the line A-A 'of FIG. 1,

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

Figs. 4A to 4E are a manufacturing process diagram of the apparatus shown in Fig. 3,

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

FIG. 6 is a cross-sectional view taken along the line D-D 'in FIG. 5,

FIG. 7 is a sectional view of the device of FIG. 5 taken along the line E-E '

Figs. 8A to 8E are diagrams showing manufacturing steps of the apparatus shown in Fig. 7; Fig.

DESCRIPTION OF THE REFERENCE NUMERALS

510: driving substrate 530: protective layer

540: etching prevention layer 560: membrane

570: lower electrode 580: strained layer

590: upper electrode 660: insulating window

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

5 is a plan view of a conventional thin film type optical path adjusting apparatus.

Referring to FIG. 5, the thin film type optical path adjusting apparatus includes an actuator 630 and a bridge 670.

One side of the actuator 630 has a quadrangular concave portion at its central portion, and the concave portion is formed into a shape that widens stepwise toward both edges. The other side of the actuator 630 has a rectangular protruding portion corresponding to the concave portion and narrowing stepwise toward the center portion. Therefore, the actuator 630 is fitted in the concave portion of the actuator adjacent to the concave portion, and the rectangular protrusion is fitted in the concave portion of the adjacent actuator.

The bridge 670 connects the actuator 630 and the adjacent actuator in the lateral direction. The actuator 630 operates stably by the bridge 670. In addition, an insulating window 660 is formed at a predetermined portion of the bridge 670 to electrically isolate the neighboring actuator.

6 is a sectional view taken along the line D-D 'in FIG.

Referring to FIG. 6, the thin film type optical path adjusting device includes a driving substrate 510 having a drain 520 formed on one side thereof, and an actuator 630 formed on the driving substrate 510.

In the driving substrate 510, M × N (M, N is an integer) transistors are embedded in a matrix form. The driving substrate 510 includes a protective layer 530 formed on the driving substrate 510 and the drain 520 and an etching prevention layer 540 formed thereon.

The actuator 630 includes a membrane 560 having one side thereof in contact with a portion where the drain 520 is formed in the lower portion of the etching prevention layer 540 and the other side being parallel to the etching prevention layer 540 via the air gap 550, A lower electrode 570 formed on the upper portion of the membrane 560, a strained layer 580 formed on the upper portion of the lower electrode 570, an upper electrode 590 formed on one side of the strained layer 580, A stripe 600 formed on a predetermined portion of the strained layer 580, a distribution electrode 560 formed from the other side of the strained layer 580 to the drain 520 through the lower electrode 570, the membrane 560, the etching prevention layer 540, And a discharge cell 620 in which the lower electrode 570 and the drain 520 are electrically connected to each other in the power distribution hole 610.

7 is a cross-sectional view of the device shown in Fig. 5 taken along the line E-E '.

7, the bridge 670 includes a driving substrate 510, a protective layer 530 formed on the driving substrate 510, an etching prevention layer 540 formed on the top of the protective layer 530, A lower electrode 570 formed on the upper portion of the membrane 560 and a predetermined portion of the lower electrode 570 are removed to form a membrane 560 having a predetermined size d ₅ , A transformer 580 formed on the upper portion of the insulating window 660 and an upper electrode 590 formed on the upper portion of the transformer 580. The insulating window 660, .

8A to 8E are process diagrams of the apparatus shown in Fig.

8A, the driving substrate 510 includes M × N (M, N is an integer) transistors (not shown) embedded in a matrix form.

The protective layer 530 is formed on the upper surface of the driving substrate 510 by a chemical vapor deposition method. The protective layer 530 is formed to a thickness of about 0.1 to 1.0 mu m. The protective layer 530 prevents damage to the driver substrate 510 on which the transistor is embedded during subsequent processing.

An etch stop layer 540 is formed on top of 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 to 2000 ANGSTROM. The etch stop layer 540 prevents the protective layer 530 and its bottom from being damaged during subsequent etching processes.

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

The lower electrode 570 is formed on the upper surface of the membrane 560 by sputtering a metal having excellent electrical conductivity such as platinum or platinum-tantalum. The lower electrode 570 is provided with an image signal.

Referring to FIG. 8B, a photoresist 640 is applied to form an insulating window 660 on the lower electrode 570. Next, an anti-glare layer 680 is formed on the photoresist 640 formed on the lower electrode 570. This diffusing reflection preventing layer 680 prevents the ultraviolet rays incident on the photoresist 640 from being irregularly reflected during a subsequent exposure process. The mask 650 is aligned on top of the anti-reflection layer 680 formed on the top of the photoresist 640.

Referring to FIG. 8C, a predetermined portion of the photoresist 640 is multiplexed by irradiating ultraviolet rays to the upper portion of the mask 650 and the anti-reflection layer 680. At this time, the portion of the photoresist 640 that is multiplexed by the mask 650 and the portion that is not multiplexed are generated. Then, portions of the photoresist 640 that are not multiplexed with ultraviolet rays are removed. However, the anti-glare layer 680 prevents the ultraviolet rays from being irregularly reflected when the ultraviolet rays are irradiated on the photoresist 640. Thus, the photoresist width (d ₅₎ is 640, the removal is consistent with the diffuse reflection layer width (d ₁₎ which 680 is to remove a group designed photoresist 140 shown in Figure 4c, so preventing the scattered reflection of the ultraviolet light do.

Referring to FIG. 8D, after the photoresist 640 is removed, a predetermined portion of the lower electrode 570 is exposed to form an insulating window 660. At this time, the width of the insulating window 660 corresponds to the width d ₃ of the designed insulating window 160 shown in FIG. 4D. Therefore, the width d ₅ of the insulating window 660 is formed to be smaller than the width d ₄ of the conventional practically formed insulating window 660 shown in Fig. 4D.

Referring to FIG. 8E, a strained layer 580 is formed on the lower electrode 570 and the upper portion of the insulating window 660. The strained layer 580 is formed of a piezoelectric material such as PZT or PZLT by a sol-gel method, a sputtering method, or a chemical vapor deposition method. The strained layer 580 is then phase-inverted by rapid thermal annealing (RTA).

An upper electrode 590 is formed on top of the strained layer 580. The upper electrode 590 is formed by a sputtering method with a metal having excellent electrical conductivity and reflection characteristics, for example, aluminum, platinum or silver. Since the width d ₅ of the insulating window 660 is formed to be the same as the designed width d ₃ , a crack generated when the width d ₅ of the insulating window 660 is widened is formed in the upper electrode 590. It is not generated.

As described above, in the method for fabricating a thin film type optical path adjusting device according to the present invention, in the process for forming an insulating window, a diffusing reflection preventing layer is formed on the upper portion of the photoresist applied on the lower electrode to prevent diffused reflection of ultraviolet rays Therefore, the insulating window can be formed to have a designed width, so that there is an effect that a crack generated in the upper electrode formed subsequently can be prevented.

Although the present invention has been described with reference to the drawings, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention as defined in the following claims. It can be understood that

Claims (2)

A protective layer 530, an etching prevention layer 540, a membrane 560, and a lower electrode 560 are formed on an upper portion of a driving substrate 510 in which M × N (M, N is an integer) transistors (not shown) (640) on top of the lower electrode (570), forming a photoresist layer (640) on the lower electrode (570) Exposing a predetermined portion of the photoresist 640 under the diffusing-preventing layer 680 to the ultraviolet ray using the mask 650; forming a photoresist 640 on the photoresist 640, Removing the portion of the photoresist 640 that is exposed to ultraviolet light to expose a portion of the lower electrode 570; and removing the photoresist 640 ) As a mask, Removing the photoresist 640 formed on the lower electrode 570 and removing the photoresist 640 formed on the lower electrode 570 and the insulating window 660. [ Forming a strained layer (580) and an upper electrode (590) in sequence on the upper layer (660). The method of claim 1, wherein the passivation layer is formed of phosphorous silicate glass, the etch stop layer is formed of nitride, the membrane is formed of nitride, The upper electrode 590 is formed of a metal having excellent electrical conductivity, the strained layer 580 is formed of a piezoelectric material, and the upper electrode 590 is formed of a metal having excellent electrical conductivity and reflection characteristics. Way.