KR19990061416A - Thin film type optical path controller - Google Patents

Abstract

The present invention relates to a thin film type optical path control apparatus capable of preventing poor contact between a pad formed on an upper portion of a driving substrate and a pad of a tape carrier package (TCP).

In the present invention, in order to prevent poor contact between the pad formed on the top of the driving substrate and the pad of the TCP, an adhesive layer is formed of an electrically conductive adhesive material on the pad. And a connection layer is formed in the upper part of a contact bonding layer thicker than before. Next, after the metal sphere is mounted on the connection layer, the metal sphere and the pad of the TCP are contacted to prevent a poor contact between the pad of the driving substrate and the pad of the TCP.

Description

Thin film type optical path controller

The present invention relates to a thin film type optical path control device, and more particularly, to a thin film type optical path control device capable of preventing poor contact between a pad formed on an upper portion of a driving substrate and a pad of a tape carrier package (TCP).

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 of the apparatus shown in FIG. 2 arranged in M × N (M, N is an integer), FIG. 4 is a plan view connecting TCP to the apparatus shown in FIG. 3, and FIG. 5 is the apparatus of FIG. Is a cross-sectional view taken along the line B-B '.

3, 4 and 5, after completing the M × N thin film type optical path control device, a method of evaporation or sputtering a metal such as chromium (Cr), copper (Cu), or gold (Au) Is deposited on the bottom of the driving substrate 10 to form an ohmic contact (not shown). In addition, a bias voltage is applied to the upper electrode 100, which is a common electrode, and an image signal is applied to the lower electrode 80, which is a signal electrode, by using a photolithography method. After etching 10), TCP 170 bonding is performed.

In more detail, a photoresist layer (not shown) is formed on the driving substrate 10 in which the pad 160, the protective layer 30, the etch stop layer 40, the sacrificial layer 50, and the membrane 70 are sequentially formed. Not stacked). That is, a photoresist layer is formed on the membrane 70.

Subsequently, after removing the photoresist layer of the portion where the pads 160 are formed in the lower direction of the photoresist layer, the membrane 70, the sacrificial layer 50, the etch stop layer 40, and the protective layer 30 are sequentially removed. Etching to expose the pad 160. When the pad 160 is exposed, the photoresist formed on the membrane 70 is removed.

Next, an ACF (Anisotropic Conductive Film) 190 is stacked on the exposed pad 160, and then the pad 180 of the TCP 170 is attached. Thus, pad 160 of AMA and pad 180 of TCP 170 are electrically connected to each other by ACF 190.

As described above, the conventional thin film type optical path control device has a problem in that a poor contact occurs between the pad of the AMA and the pad of TCP when the pad of the AMA is connected to the pad of the TCP using the ACF. .

The present invention has been made to solve the conventional problems as described above, an object of the present invention is to form a connection layer of an electrically conductive material on top of the pad formed on the top of the drive substrate and the pad formed on the top of the drive substrate; It is to provide a thin film type optical path control device that can prevent a poor contact between the pads of the TCP.

In order to achieve the above object, the present invention includes a driving substrate in which M × N (M, N is an integer) transistors are built, and a plurality of pads are formed at edges and drain pads are formed on one side; A plurality of TCPs corresponding to pads formed at edges of the driving substrate; An adhesive layer formed on an upper portion of a pad formed at an edge of the driving substrate; A connection layer formed on the adhesive layer; A metal sphere formed on the connection layer and electrically connected to the connection layer; And a pad of the TCP formed with an upper portion of the metal sphere and electrically connected thereto.

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 connecting the TCP to the device shown in FIG.

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

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

FIG. 7 is a cross-sectional view of the apparatus shown in FIG. 6 taken along line C-C '; FIG.

FIG. 8 is a plan view of the apparatus shown in FIG. 7 arranged in M × N (M and N are integers)

9 is a plan view connecting the TCP to the device shown in FIG. 8;

10 is a cross-sectional view taken along the line D-D 'of the device of FIG.

Explanation of symbols for the main parts of the 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: adhesive layer 680: connection layer

690 metal sphere 700 TCP 710 TCP pad

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.

Figure 6 shows a plan view of the thin film type optical path control apparatus according to the present invention, Figure 7 shows a cross-sectional view of the device of Figure 6 cut along the line CC '.

6 and 7, the thin film type optical path control apparatus 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. 6, 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.

FIG. 8 is a plan view of the device shown in FIG. 7 arranged in M × N (M, N is an integer), FIG. 9 is a plan view of connecting the TCP to the device of FIG. 8, and FIG. It is a cross-sectional view cut by the line 'D'.

8, 9 and 10, after completing the M × N thin film type optical path control device, a method of evaporation or sputtering a metal such as chromium (Cr), copper (Cu), or gold (Au) Is deposited on the bottom of the driving substrate 510 to form a ohmic contact (not shown).

As shown in FIG. 10, a bias voltage is applied to the upper electrode 600, which is a common electrode, and TCP 700 bonding for applying an image signal to the lower electrode 580, which is a signal electrode. After etching the driving substrate 510 at the edge of the AMA panel 650 using the photolithography method, the pad 660 is exposed, and then the TCP 700 is bonded.

In more detail, first, a photoresist is formed on the driving substrate 510 on which the pad 660, the protective layer 530, the etch stop layer 540, the sacrificial layer 550, and the membrane 570 are sequentially formed. Apply a layer (not shown). Thus, a photoresist layer is formed on the membrane 570.

Next, the membrane 570, the sacrificial layer 550, the etch stop layer 540, and the protective layer 530 of the portion where the pad 660 is formed are sequentially etched to expose the pad 660 to the outside.

Next, an electrically conductive adhesive material 670 ′ is stacked on the pad 660 and the photoresist layer. Subsequently, the adhesive material 670 ′ formed on the photoresist layer is removed to form the adhesive layer 670. The adhesive layer 670 facilitates adhesion of the connection layer 680 and the pad 660 to be described later. Thus, the adhesive layer 670 is formed on the pad 660. Then, the photoresist layer formed on the membrane 570 is removed.

Next, the connection layer 680 is formed on the adhesive layer 670 with a material having excellent electrical conductivity, for example, aluminum. The connection layer 680 is formed by a lift-off method. The lower portion of the connection layer 680 is electrically connected to the adhesive layer 670, and the upper portion thereof is formed higher than the sacrificial layer 550 to remove the step near the pad 660.

After the electrically conductive metal sphere 690 is mounted on the connection layer 680, the pad 710 of the TCP 700 is bonded to the upper portion of the metal sphere 690. Accordingly, the pad 660 of the AMA and the pad 710 of the TCP 700 are electrically connected through the adhesive layer 670, the connection layer 680, and the metal sphere 690.

As described above, the thin film type optical path control device according to the present invention forms a connection layer with a conductive material between the pad formed on the top of the drive board and the pad of the TCP, thereby reducing the step, thereby reducing the pad and the pad formed on the top of the drive board. There is an effect that can remove the poor contact between the liver.

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 (3)

A driving substrate 510 having M × N (M, N is an integer) transistors formed therein, a plurality of pads 660 at edges, and a drain pad 520 at one side thereof; A plurality of TCPs 700 corresponding to the pads 660 formed at edges of the driving substrate 510; An adhesive layer 670 formed on an upper surface of the pad 660 formed at an edge of the driving substrate 510; A connection layer 680 formed on the adhesive layer 670; A metal ball 690 formed on the connection layer 680 and electrically connected to the connection layer 680; Thin film type optical path control device having a pad (710) of the TCP (700) formed and electrically connected to the upper portion of the metal sphere (690). The apparatus of claim 1, wherein the connection layer (680) is made of an electrically conductive material. The apparatus of claim 1, wherein the adhesive layer is formed of an electrically conductive adhesive material.