KR19990035346A - Manufacturing method of thin film type optical path control device - Google Patents

Abstract

The present invention provides a driving substrate in which M × N (M, N is an integer) transistors (not shown) are embedded in a matrix form, including a drain pad on one side, and a plurality of pads on an edge thereof. Steps; I) forming a membrane in parallel with the driving substrate, one side of which is in contact with the upper portion of the driving substrate and the other side of the driving substrate through an air gap; ii) forming a lower electrode on the driving substrate; iii) forming a strained layer on top of the lower electrode; iv) forming an actuator comprising forming an upper electrode on top of the strained layer; Forming a spacer inside an AMA pad of an AMA panel in which actuators are arranged in an M × N (M, N is an integer) portion of an upper portion of the drive substrate, and an AMA pad is formed at a periphery thereof; Mounting a transparent substrate on top of the spacer; Cutting the AMA panel by a dicing method along the outside of the AMA pad to which the transparent substrate is attached.

Description

Manufacturing method of thin film type optical path control device

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a thin film type optical path control apparatus, and more particularly, to a method for manufacturing a thin film type optical path control apparatus having a spacer formed around an AMA panel in a vacuum state and a transparent substrate mounted thereon. .

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. CRT (Cathod Ray Tube) is a direct type image display device, and liquid crystal display (hereinafter referred to as LCD), DMD (Deformable Mirror Device), or AMA (Actuated) is a projection type image display device. 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 advantages described above, 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 the 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, Figure 2 is a cross-sectional view taken along the line AA 'of the device of FIG.

1 and 2, the thin film type optical path control apparatus includes a driving substrate 10 and an actuator 140 formed thereon.

The driving substrate 10 includes M x N (M, where N is an integer) MOS (Metal Oxide Semiconductor) transistors (not shown). The driving substrate 10 may include a drain pad 20 formed on one surface of the driving substrate 10, a passivation layer 30 formed on the driving substrate 10, and a top of the drain pad 20. An etch stop layer 40 is formed on the upper portion.

The actuator 140 has one side contacted to a portion where the drain pad 20 is formed in the lower portion of the etch stop layer 40, and the other side of the actuator 140 is stacked in parallel with the etch stop layer 40 through an air gap 60. A membrane 70, a bottom electrode 80 stacked on top of the membrane 70, an active layer 90 stacked on top of the bottom electrode 80, and a deformation layer 90 The upper electrode (top electrode) 100 formed on one side and the strained layer 90, the lower electrode 80, the membrane 70, the etch stop layer 60, and the protective layer 40 are formed from the other side of the strained layer 90. A distribution hole 120 vertically formed to the drain pad 20, and a power distribution 130 formed to electrically connect the lower electrode 80 and the drain pad 20 to each other in the distribution hole 120. do. A stripe 110 is formed on one side of the upper electrode 100.

In addition, referring to FIG. 1, one side of the membrane 70 has a rectangular concave portion at a central portion thereof, and the rectangular concave portion has a shape widening stepwise toward both edges. The other side of the membrane 70 has a protrusion that narrows stepwise to correspond to the recessed portion where the membrane of the adjacent actuator is stepped wide. Thus, the protrusion of the membrane 70 is formed by fitting into the concave portion of the adjacent membrane, and the protrusion of the adjacent membrane is formed by inserting into the concave portion of the membrane 70.

FIG. 3 is a plan view in which the apparatus shown in FIG. 2 is arranged in M × N (M, where N is an integer).

Referring to FIG. 3, after completing M × N thin film type AMA elements, a metal such as chromium (Cr), copper (Cu), or gold (Au) is evaporated on the lower end of the driving substrate 10. An ohmic contact (not shown) is formed by a sputtering method. In addition, in order to prepare a TCP bonding for applying a bias voltage to the upper electrode 100 and applying an image signal to the lower electrode 80 as a signal electrode, the driving substrate 10 using a conventional photolithography method. Is diced. At this time, in preparation for the subsequent process, the driving substrate 10 is diced only up to a predetermined thickness. Preferably, the driving substrate 10 is diced up to half.

Subsequently, a photoresist layer (not shown) is formed between the pads 160 of the AMA panel 150 to have a sufficient height for subsequent TCP bonding, and then the pads 160 are disposed below the photoresist layer. Patterned portions are exposed to expose the pads 160 of the AMA panel 150. Thereafter, the photoresist layer is removed, and then the driving substrate 10 diced to a predetermined depth is manually cut.

As described above, in the conventional thin film type optical path control apparatus, since the AMA panel is exposed to the air, impurities in the air are easily adsorbed on the upper part of the AMA panel, and the air resistance is affected when the actuator is operated. There has been a problem in that the driving substrate diced to depth has to be manually cut.

The present invention has been made to solve the conventional problems as described above, the object of the present invention is to form a spacer in the periphery of the AMA panel in a vacuum state and to manufacture a thin film type optical path control apparatus equipped with a transparent substrate on top of the spacer In providing a method.

In order to achieve the object described above, the present invention, M × N (M, N is an integer) transistor (not shown) is built in the form of a matrix (matrix), including a drain pad on one side and a plurality of edges Providing a driving substrate comprising two pads; I) forming a membrane in parallel with the driving substrate, one side of which is in contact with the upper portion of the driving substrate and the other side of the driving substrate through an air gap; ii) forming a lower electrode on the driving substrate; iii) forming a strained layer on top of the lower electrode; iv) forming an actuator comprising forming an upper electrode on top of the strained layer; Forming a spacer inside an AMA pad of an AMA panel in which actuators are arranged in an M × N (M, N is an integer) portion of an upper portion of the drive substrate, and an AMA pad is formed at a periphery thereof; Mounting a transparent substrate on top of the spacer; Cutting the AMA panel by a dicing method along the outside of the AMA pad to which the transparent substrate is attached.

The above objects and various advantages of the present invention will become more apparent from the preferred embodiments of the invention described below with reference to the accompanying drawings 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 shown in FIG. 1; FIG.

3 is a plan view in which the apparatus shown in FIG. 2 is arranged in M × N (M and N are integers);

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

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

6a to 6c are manufacturing process diagrams of the apparatus shown in FIG.

FIG. 7 is a plan view of the apparatus shown in FIG. 5 arranged in M × N (M and N are integers). FIG.

<Description of Symbols for Main Parts of Drawings>

510: driving substrate 520: drain pad 530: protective layer

540: etch stop layer 550: sacrificial layer 560: air gap

570: membrane 580: lower electrode 590: strained layer

600: upper electrode 610: stripe 620: power distribution hole

630: distributor 640: actuator 650: AMA panel

660: pad 670: spacer 680: glass substrate

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

4 is a plan view showing a thin film type optical path control apparatus according to the present invention, FIG. 5 is a cross-sectional view taken along line BB ′ of the apparatus of FIG. 4, and FIGS. 6A to 6C are shown in FIG. 5. It is a manufacturing process diagram of an apparatus.

4 and 5, the thin film type optical path control device includes a driving substrate 510 and an actuator 640 formed thereon.

The driving substrate 510 includes M x N (M, N is an integer) MOS (Metal Oxide Semi-conductor) transistors (not shown). The driving substrate 510 may include a drain pad 520 formed on one surface of the driving substrate 510, a passivation layer 530 and a passivation layer 530 formed on the driving substrate 510 and the drain pad 520. An etch stop layer 540 is formed on the upper portion.

The actuator 640 contacts one side of a portion of the etch stop layer 540 where the drain pad 520 is formed, and the other side thereof is stacked in parallel with the etch stop layer 540 through an air gap 560. A membrane 570, a bottom electrode 580 stacked on top of the membrane 570, an active layer 590 stacked on top of the bottom electrode 580, and a modified layer 590 The strained layer 590, the lower electrode 580, the membrane 570, the etch stop layer 540, and the protective layer 530 are formed from the other side of the upper electrode 600, the strained layer 590 formed on one side. A distribution hole 620 vertically formed to the drain pad 520, and a power distribution 630 formed in the distribution hole 620 to electrically connect the lower electrode 580 and the drain pad 520 to each other. do. A stripe 610 is formed at one side of the upper electrode 600.

In addition, referring to FIG. 4, one side of the membrane 570 has a rectangular concave portion at a central portion thereof, and the rectangular concave portion has a shape widening stepwise toward both edges. The other side of the membrane 570 has a protrusion that narrows stepwise to correspond to the recessed portion where the membrane of the adjacent actuator widens stepwise. Thus, protrusions of the membrane 570 are formed by fitting into concave portions of the adjacent membrane, and protrusions of adjacent membranes are formed by inserting into the concave portions of the membrane 570.

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

Referring to FIG. 6A, M × N (where M and N are integers) MOS transistors 520 are embedded in the driving substrate 510. Next, the drain pad 520 is formed on one surface of the driving substrate 510.

The protective layer 530 is formed on the drain pad 520 and the driving substrate 510 by chemical vapor deposition (CVD). The protective layer 530 is formed to have a thickness of about 0.1 to 1.0 μm. The protective layer 530 is made of Phospho-Silicate Glass (PSG) and prevents the driving substrate 510 from being damaged during subsequent processing.

Next, an etch stop layer 540 made of silicon nitride (Si ₃ N ₄ ) is deposited on the protective layer 530 to a thickness of about 1000 to 2000 kPa. The etch stop layer 540 is formed by Low Pressure Chemical Vapor Deposition (LPCVD). That is, the etch stop layer 540 is formed by depositing nitride on the protective layer 530 using a chemical reaction of thermal energy in a low pressure reaction vessel. The etch stop layer 540 serves to prevent the protective layer 530 and its lower portion from being damaged during the subsequent etching process.

Subsequently, a sacrificial layer 550 is deposited on the etch stop layer 540. The sacrificial layer 550 is removed by hydrofluoric acid (HF) gas after lamination of the AMA module is complete. The sacrificial layer 550 is formed of a silicate glass (PSG) having a high concentration of phosphorus (PG) to a thickness of about 0.5 to 2.0㎛ using an Atmospheric Pressure CVD (APCVD) process. That is, the sacrificial layer 550 is deposited using a chemical reaction by thermal energy in a reaction vessel under atmospheric pressure.

On the other hand, since the sacrificial layer 550 covers the surface of the driving substrate 510 in which the transistors are embedded, the flatness of the surface is very poor. Accordingly, the surface of the sacrificial layer 550 is planarized by using spin on glass (SOG) made of siloxane or silicide mixed with an alcohol-based solvent, or by using a chemical mechanical polishing (CMP) process.

Subsequently, the sacrificial layer 550 is patterned using a dry process or a wet process to create a location where the support of the actuator 640 is to be formed. For example, the sacrificial layer 550 may be etched using an etching solution such as, for example, hydrofluoric acid, or the sacrificial layer 550 may be etched using plasma or ion beam to support the actuator 640. Make a formation site.

Referring to FIG. 6B, after the support portion formation position of the actuator 640 is made, a membrane material layer 570 ′ formed of nitride is formed to a thickness of about 0.1 μm to about 1.0 μm. The membrane material layer 570 ′ is deposited using low pressure chemical vapor deposition (LPCVD), similar to the method of forming the etch stop layer 540 made of nitride. At this time, the internal stress is controlled by forming the membrane material layer 570 ′ while changing the ratio of the reactive gas with time in the low pressure reaction vessel.

Next, using a sputtering process, platinum (Pt) or platinum / tantalum (Pt / Ta) is deposited on the membrane material layer 570 'to a thickness of about 0.1 to 1.0 μm to form a lower electrode material layer 580'. To form.

After forming the lower electrode material layer 580 ', Iso-cutting is performed to separate the pixels. Subsequently, a piezoelectric ceramic or a total distortion ceramic is laminated on the lower electrode material layer 580 'by using a sol-gel method to form a strained material layer 590' which is a piezoelectric layer. For example, BaTiO ₃ , PZT (Pb (Zr, Ti) O ₃ ), which is a piezoelectric ceramic, or PLZT ((Pb, La) (Zr, Ti) O ₃ ) is deposited, or PMN (Pb ( Mg, Nb) O ₃ ) is deposited. Preferably, the strain material layer 590 ′ is formed to a thickness of about 0.1 μm to about 1.0 μm. In addition, the strain material layer 590 ′ is phase-transformed using a rapid thermal annealing (RTA) process.

Subsequently, the upper electrode material layer 600 'is formed by sputtering aluminum (Al) or platinum (Pt) having good electrical conductivity and reflectivity on top of the deformable material layer 590'.

Subsequently, the upper electrode material layer 600 'is patterned into a predetermined pixel shape to form the upper electrode 600. At the same time, a predetermined portion of the upper electrode 600 is patterned to form a stripe 610. The stripe 610 uniformly operates the upper electrode 600 to prevent diffuse reflection of the light beam incident from the light source.

Referring to FIG. 6C, a photoresist layer (not shown) is formed on the strained material layer 590 ′ and then patterned into a predetermined pixel shape to form the strained layer 590.

In this manner, the lower electrode material layer 580 ′ and the membrane material layer 570 ′ are sequentially patterned into a predetermined pixel shape to form the lower electrode 580 and the membrane 570.

After the patterning is completed as described above, the strained layer 590, the lower electrode 580, the membrane 570, the etch stop layer 540, and the protective layer from one side of the strained layer 590 by a conventional photolithography method. The distribution holes 620 are formed by sequentially etching the 530. Subsequently, the inside of the distribution hole 620 is filled with a conductive material using a sputtering process to form a power distribution 630. That is, by distributing tungsten (W) or titanium (Ti) having good conductivity to fill the distribution holes 620, a power distribution unit 630 is formed to electrically connect the drain pad 520 and the lower electrode 580. do.

The sacrificial layer 550 is removed with hydrofluoric acid after the photoresist is applied to protect the device during the subsequent etching process after forming the distributor 630. Subsequently, after the photoresist layer is removed, a rinsing and drying process is performed to remove the remaining etching solution. As such, when the sacrificial layer 550 is removed, the air gap 560 is formed.

FIG. 7 is a plan view in which the apparatus shown in FIG. 5 is arranged in M × N (M and N are integers).

Referring to FIG. 7, after completing M × N thin film type AMA elements, a metal such as chromium (Cr), copper (Cu), or gold (Au) is evaporated on the lower end of the driving substrate 510. An ohmic contact (not shown) is formed by a sputtering method. Then, a bias voltage is applied to the upper electrode 600 and an image signal is applied to the lower electrode 580 which is a signal electrode.

Next, a spacer 670 is formed around the AMA panel 650. The spacer 670 is formed by a silk printing method using frit glass and is formed up to several tens of micrometers in which the actuator 640 is easily driven. Subsequently, a transparent substrate 680 such as glass or quartz is mounted on the spacer 670 in a nitrogen atmosphere, an argon atmosphere, or a vacuum atmosphere. In the conventional thin film type optical path control apparatus, the driver substrate 510 is diced to a predetermined depth in preparation for TCP bonding for applying an image signal to the lower electrode 580, which is a signal electrode, and then the driver substrate Although the outer portion of the 510 is manually cut, in the present invention, since the transparent substrate 680 protects the AMA panel 650, the driving substrate 510 is not required to be diced to a predetermined thickness without the need for dicing the driving substrate 510 to a predetermined thickness. 510 is cut in a conventional manner. Therefore, the present invention does not require dicing the driving substrate 510 to a predetermined depth and does not need to cut the driving substrate 510 manually in the final process.

As described above, the thin film type optical path control device according to the present invention forms a spacer around the AMA panel and mounts a transparent substrate thereon to prevent adsorption of impurities in the air on the upper part of the AMA panel, and the actuator provides air resistance. It works without being affected by the effects, and there is no need to manually cut the driving substrate in the final process.

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 (4)

M × N (M, N is an integer) transistor (not shown) is built in a matrix (matrix) form a drive board including a drain pad 520 on one side and a plurality of pads 660 on the edge Providing 510; On the upper portion of the driving substrate 510, i) one side is in contact with the upper portion of the driving substrate 510 and the other side forms a membrane 570 in parallel with the driving substrate 510 via the air gap 560. Making; ii) forming a lower electrode 580 on the driving substrate 510; iii) forming a strained layer 590 on the lower electrode 580; iv) forming an actuator 640 including forming an upper electrode 600 on the deformation layer 590; The AMA pads 660 of the AMA panel 650 in which the actuators 640 are arranged in M × N (M, N are integers) in the upper portion of the driving substrate 510, and the AMA pads 660 are formed in the periphery thereof. Forming a spacer 670 inside thereof; Mounting a transparent substrate 680 on the spacer 670; And a step of cutting the AMA panel 650 along the outside of the AMA pad 660 to which the transparent substrate 680 is attached by a dicing method. The method of claim 1, wherein the spacer (670) is formed of frit glass. The method of claim 2, wherein the spacer 670 is formed by a silk printing method. The method of claim 1, wherein the transparent substrate is mounted in an atmosphere of nitrogen, argon, or vacuum when the transparent substrate is mounted on the spacer.