JPS62252964A - Active matrix substrate housed in driver - Google Patents

Abstract

PURPOSE:To prevent dielectric breakdown of a thin film transistor in a driving circuit due to charge-up of electric charge to the surface at the time of ion implantation and the like, by shielding the driving circuits at the peripheral part by the interconnection of conductor films. CONSTITUTION:Gate lines (G1-Gm) are timing lines. Source lines 2 (S1-Sn) are data lines. A thin film transistor 3 and a picture element electrode 4 are arranged at each intersection of the gate line 1 and the source line 2. Timing- line driving circuits 5 and data-line driving circuits 6 are formed. The driving circuits 5 and 6 are covered with interconnecting wires using the same material as that of the gate lines 1 and connected to the periphery of a transparent insulating substrate with the same material. Therefore, The thin film transistors in the driving circuits 5 and 6 are perfectly shielded. Thus dielectric breakdown due to ion implantation and the like is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to the structure of an active matrix substrate with a built-in driver, in which thin film transistors are formed on a transparent insulating substrate.

[Conventional technology]

In recent years, the performance of MO3 type thin film transistors, which use semiconductor thin films deposited on insulating substrates as active regions, has improved to such an extent that they can be used not only as optical switches for pixels in liquid crystal display devices, but also as peripheral drive circuits. But 7,
In devices using insulating substrates, the challenge is how to dissipate charges generated on the surface of the insulating substrate to the outside and prevent dielectric breakdown of thin film transistors. Particularly in devices such as liquid crystal display devices where the panel display area is large, it is important to prevent charge-up on the substrate surface during the manufacturing process.

FIG. 2 is a schematic diagram of an active matrix substrate with a built-in driver for a liquid crystal display, which is composed of thin film transistors and peripheral drive circuits arranged in a matrix on a transparent insulating substrate. 1 (G, ~(), , ) are gate lines serving as timing lines, 2 (S1~Ss) are source lines serving as data lines, and thin film transistors 3 and pixel electrodes 4 are gate lines, Located at the intersection of the source lines.

5 is a timing line drive circuit, and 6 is a data line drive circuit. In this figure, both sides are driven. FIG. A plan view near the outer periphery of (
α) and cross-sectional view Cb). A polycrystalline silicon thin film 8 is deposited on a transparent insulating substrate 7 by a CVD method in which crystals or amorphous materials are deposited through a chemical reaction. Next, after patterning the polycrystalline silicon thin film, a gate insulating film 9 is formed, and a gate electrode 10 and a gate line 1 made of metal or polycrystalline silicon thin film are formed on the gate insulating film 9 inside the drive circuit. Form simultaneously. Next, using the gate electrode 10 and a resist as a mask, P-type impurity ions and N-type impurity ions are selectively implanted to form source and drain regions of P-type and N-type thin film transistors. Next, an interlayer insulating film 11 is laminated by the CVD method, a contact hole is opened, a transparent conductive film is deposited, a pixel electrode 4 is formed, and a metal is deposited to form the source line 2 and the surrounding area. This is assumed to be wiring within the timing line drive circuit 5 and data line drive circuit 6.

[Problem that the invention seeks to solve]

However, in the above-mentioned conventional technology, there is no escape route for charges built up on the transparent insulating substrate during the ion implantation process, and therefore dielectric breakdown of the thin film transistor is likely to occur.

For this reason, when implanting ions, an implantation method is used in which the implanted ions are neutralized by thermoelectrons near the substrate surface, but complete neutralization is difficult, and slight damage occurs that is not apparent from the outside. In particular, by cutting the thin film transistor that drives a pixel using a laser or the like, only the pixel can be sacrificed. However, the film transistors in the peripheral drive circuit portion are 1
If there is any defect at any time, a problem arises in that it causes malfunction. SUMMARY OF THE INVENTION The present invention is intended to solve these problems, and an object of the present invention is to provide a peripheral drive circuit in which the dielectric breakdown strength of thin film transistors is increased.

[Hiratan to solve problems]

The active matrix substrate with a built-in driver of the present invention is characterized in that the peripheral drive circuit is surrounded by conductive film wiring, and a conductive film region is also provided around the substrate to short-circuit the two.

[Effect]

According to the above-described structure of the present invention, the drive circuit is shielded by conductive film wiring, and the charges that are recharged from the display area that occupies a large area can be dissipated to the outside by grounding the periphery of the substrate. Therefore, it is possible to eliminate damage to the thin film transistor in the drive circuit.

〔Example〕

FIG. 1 is an embodiment of the present invention, and is a plan view of the vicinity of the outer periphery of an active matrix substrate with a built-in driver for liquid crystal display. Compared to the conventional example shown in Figure 3, the drive circuit is surrounded by wiring made of the same material as the gate line, and is connected to the periphery of the transparent insulating substrate using the same material. Since the transistor is completely shielded, dielectric breakdown due to ion implantation or the like can be sufficiently prevented. The wiring surrounding the drive circuit does not need to be made of the same material as the gate line as on the actual flow side, and is made of JJ4.
There is no problem in using a conductive film of any kind. The wiring width is
A thickness of 10 micrometers is sufficient, occupies a small area, and does not increase the number of steps, which is advantageous.

〔Effect of the invention〕

As described above, according to the present invention, the peripheral drive circuit is shielded by conductive film wiring, which prevents dielectric breakdown of the thin film transistor in the drive circuit due to charge build-up on the surface due to ion implantation, etc. It has the effect of preventing Also, in cleaning processes such as oxygen plasma,
This helps prevent damage.

[Brief explanation of drawings]

FIG. 1 is a plan view of the vicinity of the outer periphery of an active matrix substrate with a built-in driver for liquid crystal display according to the present invention. FIG. 2 is a schematic diagram of an active matrix substrate with a built-in driver for liquid crystal display. FIG. 3 is a plan view (α) and a cross-sectional view (b) of the vicinity of the outer periphery of a conventional active material with a built-in driver for liquid crystal display (IJ sock board). 1... Gate line (timing line) 2...
- Source line (data line) 3... Thin film transistor 4... Pixel electrode 5... Timing line drive circuit 6... Data line drive circuit 7... ...Transparent insulating substrate 8...Polycrystalline silicon thin film 9...Gate insulating film 10...Gate electrode 11...Interlayer insulating film 12...Contact hole and above Applications People Seiko Epson Corporation Figure 1

Claims (3)

[Claims] (1) It has a plurality of data lines and a plurality of timing lines that are perpendicular to each other, and a thin film transistor and a pixel electrode to be switched by the thin film transistor are provided at the intersection of the data line and the timing line, and the data line and the timing line are provided at the intersection of the data line and the timing line. In an active matrix substrate with a built-in driver, in which at least one of the drive circuits is configured on the same transparent insulating substrate, the drive circuit is surrounded by wiring of a conductive film, and a conductive film is also provided around the substrate to prevent a short circuit with the wiring. An active matrix board with a built-in driver. (2) The active matrix substrate with a built-in driver according to claim 1, wherein the wiring layer surrounding the driver is the same layer as a gate wiring layer of a thin film transistor in the drive circuit. (3) The active matrix substrate with a built-in driver according to claim 1, wherein the wiring layer surrounding the driver is the same layer as the gate wiring layer of the pixel electrode switch layer thin film transistor.