JPS63287825A - Active matrix substrate plate - Google Patents

Abstract

PURPOSE:To enable the correct decision of a short circuiting portion by constituting one sides of a 1st and a 2nd wirings of an electrically transparent conductive film in the neighbourhood of the crossing part of the 1st and the 2nd wiring respectively. CONSTITUTION:The 1st wiring is constituted of a timing line 2 and a common film 3 for building image element capacity, and the 2nd wiring is constituted of a video wiring. The 2nd wiring is arranged at an upside of the 1st wiring, and is composed of the transparent electrode film in the neighbourhood of the crossing part to facilitate an appearance inspection from the surface of a substrate. Accordingly, the video wiring 2 is constituted of two layer structures of the electrically transparent conductive film 15 and a metallic thin film 16. Thus, the appearance inspection about whether the short circuiting of the 1st and the 2nd wirings occurs in the crossing part of said wirings or not, or what place the short circuiting occurs, is easily effected, without remarkably reducing the wiring resistance of the title plate, by constituting at least one side of the 1st and the 2nd wirings of the electrically transparent conductive film in the neighbourhood of the crossing part respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention is directed to the structure of an active matrix substrate in which thin film transistors are formed on an insulating substrate.

[Conventional technology]

In recent years, MO3 type thin film transistors, which use a semiconductor thin film deposited on an insulating substrate as an active region, have been used as optical shutter switches for liquid crystal panels.

FIG. 3 is a schematic diagram of an active matrix substrate using conventional thin film transistors. 1 (S-, St.
) is the data line, 2 (G,,G.

) is a timing line. 3 (C,,C,...
・) is a common gland for building pixel capacitance, and is a constant potential line that aims to add additional capacitance to the pixel capacitance and improve retention characteristics when the pixel capacitance created by the liquid crystal is small. The signal on the data line 1 is written to each pixel electrode 5 via the thin film transistor 4 in accordance with the signal on the timing line 2 .

FIG. 4 is a structural plan view of a part of the active matrix substrate, and FIG. 5 is a structural cross-sectional view taken along line bb' in FIG. 4.

The thin film transistor 4 consists of a process of depositing and patterning a polycrystalline silicon thin film 7 on a transparent glass substrate 6, depositing a gate insulating film 8, a gate metal thin film, a gate electrode 9, and timing! ! i! 2, using the gate electrode 9 as a mask, ions of P-type or N-type impurities are implanted to form a source region 10 and a drain region 11.
a step of depositing an interlayer insulating film 12; a step of depositing a metal thin film and patterning the common gland 3 for forming the pixel capacitance; laminating the insulating film 13 for forming the pixel capacitor; , a step of depositing a transparent conductive film and patterning the pixel electrode 4, and a step of depositing a metal thin film and patterning the data 1ill.

[Problems to be Solved by the Invention] However, when the defect f22iT% is repaired using a laser in the active matrix substrate manufactured by the above-mentioned conventional technique, the following problems occur.

The first case is the correction of a defect due to a short circuit between the data line 1 and the timing line 2. The factors include data, I
A short circuit may occur due to a pinhole in the interlayer insulating film at the intersection of II and the timing line 2, and a pinhole or electrostatic breakdown in the gate insulating film 8 between the source region 10 and gate electrode 9 of the thin film transistor 3 may cause a short circuit. A short circuit may occur. Therefore, it is necessary to determine which mode is causing the defect through an external inspection using a microscope. At this time, data is caused by weak electrostatic discharge damage in thin film transistors, small pinholes in interlayer insulating films, and especially cracks at stepped areas!
1 and timing il! i! It is difficult to detect a short circuit or the like in No. 2 when both the data line and the timing line are metal wiring, so there is a problem that an appropriate judgment cannot be made.

The second case is the case of correcting a defect due to a short circuit between the data line 1 and the pixel capacitance building connector 3. Common for building pixel capacitance! ! ! 3 is a constant potential, so data, II
It is electrically difficult to find out which intersection with I is short-circuited, and it is necessary to find the short-circuit location along the data line. In this case as well, short circuits due to small pinholes etc. are difficult to detect when both the data line and the timing line are metal wiring.

Therefore, the present invention solves the following problems.
The purpose is to provide an active matrix substrate that can correctly identify short circuit locations.

[Means for solving problems]

The active matrix substrate of the present invention has a plurality of parallel second wirings orthogonal to a plurality of parallel first wirings, and each pixel electrode is provided near the intersection of the first and second wirings. In an active matrix substrate on which a thin film transistor for driving is arranged, at least one of the first and second wirings is connected to an intersection of the first and second wirings;
It is characterized by a transparent conductive film in the vicinity.

[Effect]

According to the above configuration of the present invention, since at least one of the first wiring and the second wiring is made of a transparent conductive film near the intersection, it is possible to detect that the living room insulating film at the intersection is visually inspected by a microscope. If there is a small abnormality, the defective location can be easily identified. When the first wiring is located below the second wiring and a part of the second wiring is made of a transparent conductive film, the appearance inspection is performed by observing from the front side of the substrate and checking whether a part of the first wiring is If it is made of a transparent conductive film, it may be observed from the back side of the substrate.

〔Example〕

FIG. 1 is a structural plan view of a part of the active matrix substrate of the present invention, and FIG. 2 is a structural cross-sectional view taken along line 1-a' in FIG.

The first wiring is a timing line 2 and a common gland 3 for building pixel capacitance, and the second wiring is a video line. In this example, the second wiring is located above the first wiring, and a transparent electrode film is formed on the second wiring near the intersection so that the appearance can be inspected more easily than the substrate surface. Therefore, the video line 2 has a two-layer structure of a transparent conductive film 15 and a metal thin film 16.

Specifically, a transparent conductive film and a thin film of metal such as molybdenum or chromium are laminated in two layers as the second wiring layer, and the video lines are patterned in the two layers simultaneously using photolithography, and then the first wiring layer is formed. This can be easily done by removing the overlying metal thin film again using photophosphorography. Another method is to deposit a transparent conductive film and photolithographically pattern the video lines, and then
After removing the resist only in the area where the metal thin film is desired to be deposited and depositing the metal film, the resist is wiped off to form a pattern, or a transparent conductive film is deposited and video lines are patterned using photolithography, and then insulated. A plating method may be considered in which a film is deposited, the insulating film is removed only from the portion where the metal thin film is desired to be deposited, and a plating film of nickel or the like is deposited on the transparent conductive film by electroless plating.

Conversely, when a part of the first wiring is made of a transparent conductive film,
The first wiring may be formed in the same manner as described above, and the appearance may be inspected from the back surface of the substrate.

〔Effect of the invention〕

As described above, according to the present invention, at least one of the first and second wirings is made of a transparent conductive film in the vicinity of the intersection. It is possible to easily determine by visual inspection whether a short circuit between the wiring and the second wiring is at an intersection, and if so, where it is located, so that defects can be corrected appropriately using a laser. . In particular, when performing laser correction after assembly into a liquid crystal panel, there is usually a light-shielding layer on the counter substrate facing the data lines and timing lines, so it is impossible to visually inspect the vicinity of the intersection from the counter substrate side.

Therefore, it is necessary to conduct a visual inspection from the back side of the active matrix substrate, and when the first wiring is located below the second wiring, if a transparent conductive film is used near the intersection of the first wiring, it is possible to identify the defective location. However, it has the advantage of being clear.

[Brief explanation of drawings]

FIG. 1 is a structural plan view of a part of the active matrix substrate of the present invention, and FIG. 2 is a structural cross-sectional view taken along line aa' in FIG. FIG. 3 is a schematic diagram of an active matrix substrate using conventional thin film transistors. FIG. 4 is a structural plan view of a part of a conventional active matrix substrate, and FIG. 5 is a structural cross-sectional view taken along line bb' in FIG. 1... Data line 2... Timing line 3... Common gland for building pixel capacitance 4... Thin film transistor 5... Pixel electrode 6... Transparent glass substrate 7... Polycrystalline silicon thin film 8... Gate insulating film 9... Gate electrode 10... Source region 11... Drain region 12... Interlayer insulating film 13... Insulating film for building pixel capacitance 14... Contact hole 15 ...Transparent conductive film 16...Metal thin film or more

Claims (3)

[Claims] (1) A thin film transistor having a plurality of parallel second wirings orthogonal to a plurality of parallel first wirings, and driving each pixel electrode near the intersection of the first and second wirings. In the active matrix substrate on which the first
An active matrix substrate characterized in that at least one of the first and second wirings is made of a transparent conductive film near the intersection of the first and second wirings. (2) The active matrix substrate according to claim 1, wherein the first and second wirings are a data line and a timing line. (3) The active matrix substrate according to claim 1, wherein the first and second wirings are one of a data line and a timing line, and a common line for building pixel capacitance. .