JPH10104648A - Active matraix substrate and its defect correcting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the active matrix substrate which is reducible in substrate size by eliminating the need for preliminary wiring, makes it possible to correct the breaking of all source bus lines, and also enables the breaking of plural parts of the same source bus line to be corrected. SOLUTION: A 1st connection area 3' where a pixel electrode 4 overlaps with a source bus line 3 across an inter-layer insulating film is formed. Further, a 2nd connection area 9 where a connection wire 9 overlaps with two pixel electrodes 4 and 4 across an inter-layer insulating film is formed at two pixel electrode parts which adjoin to each along the source bus line across a gate bus line 2. To correct a defect due to an open circuit, the 1st connection area 3' and 2nd connection area 9 are worked with a laser to connect one source bus line 3a which is disconnected at the open-circuit part to the pixel electrode 4 and also connect the pixel electrodes which adjoin to each other along the source bus line to each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an active matrix type liquid crystal display device which is used for a display such as a computer or a television set and executes display by applying a drive signal to a pixel electrode via a switching element. And a defect repairing method thereof.

[0002]

2. Description of the Related Art FIG. 5 shows a conventional example of this type of active matrix substrate. The active matrix substrate includes switching elements 1 formed in a matrix,
A plurality of pixel electrodes 4 formed in a matrix corresponding to each switching element 1 and a gate bus line 2 and a source bus line 3 formed orthogonal to each other in a row direction and a column direction. Have.

Here, a gate bus line 2 is connected to a thin film transistor (hereinafter, referred to as a TFT 1) as a switching element 1.
(Hereinafter referred to as “gate”), and drive control of the TFT 1 by applying a scanning signal to the gate electrode. On the other hand, the source bus line 3 is connected to the source electrode of each TFT 1, and supplies a data signal to the pixel electrode 4 via the TFT 1 when driving the TFT 1. The pixel electrode 4 and one terminal of the additional capacitor 7 are connected to the drain electrode of the TFT 1, and the other terminal of the additional capacitor 7 is connected to the additional capacitor line 8. Connected to counter electrode.

In order to manufacture a high-definition liquid crystal display device, it is necessary to increase the number of pixels. That is, it is necessary to reduce the size of the switching elements and increase the number thereof. However, in this case, when manufacturing the active matrix substrate, electric leakage easily occurs between the pixel electrode and the bus line or between the bus lines due to the accuracy of the device and dust. This leak causes a point defect or a line defect when the display device is turned on. In particular, a line defect treated as a heavy defect becomes a serious problem in terms of product yield. For this reason, it is necessary to correct the disconnection of the source bus line which is the main cause of the line defect.

FIG. 6 shows a conventional example of an active matrix substrate in consideration of correction of a defect caused by disconnection of a source bus line. This active matrix substrate has spare wirings 20 and 21 outside the display section. When the source bus line 3 is disconnected at a position indicated by A in the drawing, one of the source bus lines 3a sandwiching the disconnected portion
And the other source bus line 3b is connected to another spare wiring 21. The spare wirings 20 and 21 are usually connected by a connecting wiring 22 in the drive circuit board. As a result, the signal sent from the drive circuit to the source bus line 3a branches at the connection between the source bus line 3a and the spare wiring 20, and one of the signals goes to the disconnection point, while the other goes to the wiring 22 in the drive circuit board. As described above, the connection between the source bus line 3b and the spare wiring 21 reaches the source bus line 3b.

[0006]

In the above-mentioned conventional active matrix substrate, the disconnection of the source bus line is corrected by the spare wiring provided outside the display section. However, providing spare wirings for a large number of source bus lines is not a good idea in view of the area occupied by the spare wirings and the probability of line defects. For this reason, the whole is usually divided into several blocks, and a number of spare wirings are provided for each block.

However, with such a structure, it is impossible to correct a line defect beyond a specified number. Further, although the number is small, the area occupied by the spare wiring is not small, so that the size of the substrate is increased. Further, it is impossible to correct a plurality of disconnections in the same bus line.

The present invention has been made in view of such circumstances, and there is no limitation on the number of disconnection correction lines, no increase in substrate size, and it is possible to correct a plurality of disconnections on the same bus line. It is an object of the present invention to provide an active matrix substrate and a method for repairing the defect.

[0009]

According to the active matrix substrate of the present invention, switching elements are formed in a matrix, and a gate bus line for controlling the switching elements and a source bus line for supplying a data signal to the switching elements are orthogonal. And an interlayer insulating film is formed on the switching element, the gate bus line and the source bus line, and is surrounded by the gate bus line and the source bus line on the interlayer insulating film. A pixel electrode formed in the region is connected to a drain electrode of the switching element through a contact hole penetrating the interlayer insulating film, and a transmissive display using a highly transparent organic thin film as the interlayer insulating film is used. In the active matrix substrate used in the device, the pixel electrode is connected to the source via the interlayer insulating film. First that overlaps the bus lines and partially
And a connection line for connecting two pixel electrodes adjacent to each other in the direction of the source bus line sandwiching the gate bus line, and the connection line is adjacent to the pixel electrode via the interlayer insulating film. A second connection area partially overlaps with each of the two pixel electrodes, whereby the object is achieved.

Preferably, the source bus line is constituted by a lower transparent conductive film and an upper metal film, and the connection wiring is formed by the transparent conductive film.

The method of repairing a defect of an active matrix substrate according to the present invention is the method of repairing a defect of an active matrix substrate according to claim 1 or 2, which is caused by the disconnection of the source bus line. Cutting both sides of the disconnection point of the source bus line,
Processing the first connection area connected to each of the separated source bus lines and connecting the source bus line to the pixel electrode; processing the second connection area; Connecting the adjacent pixel electrodes to each other, thereby achieving the above object.

The operation of the present invention will now be described with reference to FIGS. 1, 3 and 4.
This will be specifically described with reference to FIG.

As shown in FIG. 1, the active matrix substrate of the present invention has a source bus line partially formed with a projection protruding toward the pixel electrode 4. That is, two projections are formed for one pixel electrode 4 formed in a matrix. The projection overlaps the pixel electrode 4 via the interlayer insulating film, and the overlapping portion is hereinafter referred to as first connection areas 3 ', 3'.

In two pixel electrode portions adjacent to each other in the source bus line direction with the gate bus line 2 interposed therebetween, a connection wiring 9 (second connection area) is provided with two pixel electrodes 4 via an interlayer insulating film. , 4 partially overlap.

In the active matrix substrate having such a structure, the gate bus line 1 and the source bus line 3
It is assumed that a leak has occurred at the intersection B of FIG. This defect correction is performed in the following procedure.

First, the source bus line 3 is cut at positions C and D with the intersection B interposed therebetween. Next, for example, the first connection areas 3 ′, 3 ′ (connection areas 3 ′, 3 ′ close to the cut location) formed on the two cut source bus lines 3 a, 3 b are, for example, As shown in FIG. 3, laser processing is performed by irradiating a laser beam from the insulating substrate 11 side, thereby removing the interlayer insulating film 18 at this position.
The source bus line 3 and the pixel electrode 4 are electrically connected.

More specifically, when a laser beam is irradiated, as shown in FIG. 3, a penetrating portion 30 is formed in the irradiated portion, and at this time, a connection area 3 'around the penetrating portion 30 is formed.
Is melted, and the melted portion 3 ″ sticks to the pixel electrode 4. As a result, the source bus line 3 and the pixel electrode 4 are electrically connected.

Subsequently, the second connection area 9 is also irradiated with a laser beam (more specifically, a position indicated by x in the figure), the interlayer insulating film at this position is removed, and the adjacent pixel electrode 9 is removed. The wires 4 and 4 are electrically connected to each other by the connection wiring 9.

More specifically, when a laser beam is irradiated to this portion in the same manner as described above, a through portion 90 is formed in the irradiated portion as shown in FIG. The area 9 'melts, and the melted portion 9' sticks to the pixel electrode 4. As a result, the adjacent pixel electrodes 4 and 4 are electrically connected to each other via the connection area 9 and the melted portion 9 '.

By the above correction processing, the source bus line 3 is electrically connected in the column direction bypassing the cut portion,
Since a data signal can be applied to each pixel electrode 4 from the source bus line 3, a line defect is corrected.

As described above, according to the active matrix substrate of the present invention, it is possible to repair a defect caused by a disconnection without providing a spare wiring for repairing the disconnection outside the display section. Therefore, the substrate size can be reduced.

Further, since the disconnection can be corrected for all the source bus lines, the number of corrections is not limited. Further, if a structure in which a plurality of first connection areas are provided for one pixel electrode is adopted, it is possible to correct a plurality of disconnections in one source bus line corresponding to each pixel electrode.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below with reference to the drawings.

First, the planar structure of the active matrix substrate will be described with reference to FIG. On a transparent insulating substrate 11 (see FIG. 2), a gate bus line 2 and a source bus line 3 are formed orthogonally in the vertical and horizontal directions. Each pixel electrode 4 is formed in a matrix in a rectangular area surrounded by the gate bus line 2 and the source bus line 3 via an interlayer insulating film 18 (see FIG. 2).

Each pixel electrode 4 is connected to a TFT 1 as a switching element for driving the pixel electrode 4 for display. More specifically, the drain electrode of the TFT 1 and the pixel electrode 4 are connected by the connection electrode 6 via the contact hole 5 penetrating the interlayer insulating film 18. The gate electrode of the TFT 1 is connected to the gate bus line 2, and the source electrode is connected to the source bus line 3.

An additional capacitance line 8 is formed between the adjacent gate bus lines 2 and 2 in parallel with the gate bus line 2.

In addition, at a portion of the source bus line 3 located between the adjacent gate bus lines 2, 2, a protruding portion is formed protruding toward the pixel electrode 4 in the vicinity of each gate bus line 2, 2. I have. Each projection overlaps the pixel electrode 4 via the interlayer insulating film 18, and a first connection area 3 'is formed in the overlap.

In two pixel electrode portions adjacent to each other in the source bus line direction with the gate bus line 2 interposed therebetween, a connection wiring 9 partially overlaps with the two pixel electrodes 4 and 4 via an interlayer insulating film. A second connection area 9 is formed in the overlapping portion.

Next, a sectional structure of the active matrix substrate and a method of manufacturing the same will be described with reference to FIG.

First, a gate bus line 2, a gate electrode 12, and a gate insulating film 1 are formed on a transparent insulating substrate 11.
3, semiconductor layer 14, channel protective film 15, and TFT
An n + / Si layer 16 serving as one source / drain electrode is sequentially stacked. Next, an ITO film 17 ′, which is a transparent conductive film constituting the source bus line 3, and a metal layer 17 are laminated by a sputtering method, and are patterned to form the source bus line 3 and the source electrode 16.

Here, the source bus line 3 is connected to the ITO film 1
The two-layer structure including the metal layer 7 'and the metal layer 17 is such that even if a part of the metal layer 17 has a film defect, the ITO film 17'
This ensures conduction of the source bus line 3.

Next, a photosensitive acrylic resin as an interlayer insulating film 18 is applied thereon by spin coating.
For example, it is formed to a thickness of 3 μm. Subsequently, the interlayer insulating film 1
In order to form the contact hole 5 in 8, the acrylic resin is exposed to light in a desired pattern, and is treated with an alkaline solution.

Here, a photosensitive acrylic resin is used as the interlayer insulating film 18 because a thin film having a thickness of several μm can be easily formed since a thin film can be formed by a spin coating method. This is advantageous in improving productivity, for example, by eliminating the need for a photoresist coating step.

Subsequently, the pixel electrode 4 is formed on the interlayer insulating film 18.
Are laminated by sputtering and patterned. The pixel electrode 4 is connected to the ITO film 17 ′ through the contact hole 5 penetrating the interlayer insulating film 18, and is connected to the drain electrode 16 of the TFT 1 through the ITO film 17 ′.

As described above, in the active matrix substrate of this embodiment, the drain electrode of the TFT 1 and the pixel electrode 4
Is formed of an ITO film 17 ′, and a connection wiring 9 for connecting two pixel electrodes 4, 4 adjacent in the direction of the source bus line 3 is formed by the ITO film 17 ′. Is formed.

Next, a method for correcting a defect of the active matrix substrate caused by the disconnection of the source bus line 3 will be specifically described with reference to FIGS. In FIG. 1, a black circle indicates a disconnection position, and a cross indicates a connection position.

Now, it is assumed that a leak has occurred at the intersection B between the gate bus line 2 and the source bus line 3 due to a disconnection, and a line defect has occurred. First, the source bus line 3 is cut at positions C and D with the intersection B interposed therebetween. Next, for example, a laser is applied to the first connection areas 3 ', 3' (the connection areas 3 ', 3' close to the cut location) formed on the two cut source bus lines 3a, 3b. Laser processing for irradiating a beam is performed, whereby the interlayer insulating film at this position is removed, and the source bus line 3 and the pixel electrode 4 are electrically connected.

More specifically, when a laser beam is irradiated, as shown in FIG. 3, a penetrating portion 30 is formed in the irradiated portion, and at this time, a connection area 3 'around the penetrating portion 30 is formed.
Is melted, and the melted portion 3 ″ sticks to the pixel electrode 4. As a result, the source bus line 3 and the pixel electrode 4 are electrically connected.

Subsequently, the second connection area 9 is also irradiated with a laser beam (more specifically, at the position indicated by x in the figure), the interlayer insulating film at this position is removed, and the adjacent pixel electrode 9 is removed. The wires 4 and 4 are electrically connected to each other by the connection wiring 9.

More specifically, when a laser beam is irradiated to this portion in the same manner as described above, a through portion 90 is formed in the irradiated portion as shown in FIG. The area 9 'melts, and the melted portion 9' sticks to the pixel electrode 4. As a result, the adjacent pixel electrodes 4 and 4 are electrically connected to each other via the connection area 9 and the melted portion 9 '.

By the above correction processing, the source bus line 3 is electrically connected in the column direction bypassing the cut portion,
Since a data signal can be applied to each pixel electrode 4 from the source bus line 3, a line defect is corrected.

As described above, according to the active matrix substrate of the present invention, it is possible to repair a defect caused by a disconnection without providing a spare line for repairing a disconnection outside the display section. Therefore, the substrate size can be reduced.

Further, since the disconnection can be corrected for all the source bus lines, the number of corrections is not limited. Further, the active matrix substrate of the present embodiment employs a structure in which a plurality of connection areas 3 'are provided for each pixel electrode, so that a plurality of connection areas 3' are provided for one source bus line corresponding to each pixel electrode. It is also possible to correct a disconnection at a location.

In the above-described embodiment, the connection wiring 9 for connecting the adjacent pixel electrodes 4 and 4 is formed by the ITO film 17 ′ located below the source bus line 3 having the two-layer structure.
But not limited to this, source metal,
That is, the upper metal layer 17 may be used, or the ITO film 1 may be used.
As a two-layer structure of 7 ′ and the metal layer 17, it is also possible to adopt a structure in which the connection with the pixel electrodes 4 and 4 can be performed more stably. Further, it is also possible to make the interlayer insulating film 18 thin at the portion of the connection wiring 9 so as to make the connection with the pixel electrodes 4 and 4 easy.

[0045]

The active matrix substrate according to the present invention has a first connection area and a second connection area. If these areas are subjected to, for example, laser processing, the cut source bus line can be obtained. And the pixel electrodes are electrically connected, and the pixel electrodes adjacent in the source bus line direction are electrically connected to each other. Therefore, the source bus line is connected in the column direction bypassing the cut portion, and the data signal can be applied to each pixel electrode from the source bus line, so that the line defect is corrected.

As described above, according to the active matrix substrate of the present invention, it is possible to repair a defect caused by a disconnection without providing a spare wiring for repairing a disconnection outside the display section. Therefore, the substrate size can be reduced.

Further, since the disconnection can be corrected for all the source bus lines, the number of corrections is not limited. Further, if a structure in which a plurality of first connection areas are provided for one pixel electrode is adopted, it is possible to correct a plurality of disconnections in one source bus line corresponding to each pixel electrode.

[Brief description of the drawings]

FIG. 1 is a plan view of an active matrix substrate of the present invention.

FIG. 2 is a sectional view taken along line XX of FIG.

FIG. 3 is a sectional view showing a method for connecting a source bus line and a pixel electrode.

FIG. 4 is a cross-sectional view showing a method of connecting adjacent pixel electrodes.

FIG. 5 is an equivalent circuit diagram showing a conventional example of an active matrix substrate.

FIG. 6 is a schematic plan view showing a conventional example of an active matrix substrate provided with a spare wire for disconnection correction.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 TFT 2 Gate bus line 3 Source bus line 3 '1st connection area 4 Pixel electrode 5 Contact hole 6 Connection electrode 8 Additional capacitance wiring 9 Connection wiring (2nd connection area) 11 Insulating substrate 12 Gate electrode DESCRIPTION OF SYMBOLS 13 Gate insulating film 14 Semiconductor layer 15 Channel protective film 16 n + / Si layer 17 Metal layer 17 'ITO film 18 Interlayer insulating film 19 Transparent conductive film

Claims (3)

[Claims] A switching element is formed in a matrix, and a gate bus line for controlling the switching element and a source bus line for supplying a data signal to the switching element are formed to be orthogonal to each other. An interlayer insulating film is formed on the bus line and the source bus line, and a pixel electrode formed on the interlayer insulating film in a region surrounded by the gate bus line and the source bus line is formed on the interlayer insulating film. An active matrix substrate connected to a drain electrode of the switching element through a contact hole penetrating an insulating film and used for a transmission type display device using an organic thin film having high transparency as the interlayer insulating film, A first connection area partially overlapping the source bus line via the interlayer insulating film; Has a connection wiring for connecting the two pixel electrodes adjacent to the source bus line direction sandwiching the gate bus line, the connection wiring is the adjacent via the interlayer insulating film 2
An active matrix substrate having two pixel electrodes and a second connection area partially overlapping each other. 2. The active matrix substrate according to claim 1, wherein said source bus line comprises a lower transparent conductive film and an upper metal film, and said connection wiring is formed by said transparent conductive film. 3. The method for repairing defects in an active matrix substrate according to claim 1, wherein the source bus line is disconnected due to the disconnection of the source bus line. Cutting the first connection area connected to each of the separated source bus lines, connecting the source bus line to the pixel electrode, and processing the second connection area. Connecting the adjacent pixel electrodes with each other by the connection wiring.