JPH04283725A - Thin film transistor matrix and its wire break repairing method - Google Patents

Abstract

PURPOSE:To repair the breaking of a wire even in the later period of a manufacturing process. CONSTITUTION:The thin film transistor(TFT) matrix consists of plural TFTs 20, a 1st bus line 32 to which 1st electrodes of the TFTs are connected, a 2nd bus line 34 to which 2nd electrodes of the TFTs are connected, a display electrode 28 which is connected to 3rd electrodes of the TFTs, and a conductor layer 42 for repair which is provided in an electrical floating state at a position where it overlaps with at least one of the 1st bus line and 2nd bus line, e.g. 34 across insulating layers 30, 38, and 44.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film transistor matrix and a method for repairing disconnection thereof. Recently, for example, liquid crystal display panels, electroluminescence, and the like have been increasingly used as displays for televisions. A large number of pixels are required to obtain a large, high-resolution television, and in order to drive such a large number of pixels in liquid crystal display panels, electroluminescence, etc., it is necessary to use a thin film transistor matrix with active elements. It is a promising material, and the development of thin film transistor matrices has been active recently.

0002

2. Description of the Related Art A thin film transistor matrix is a matrix in which a plurality of thin film transistors (TFTs), gate bus lines, drain bus lines, and display electrodes are formed in a transparent insulating substrate. A counter solid electrode film is formed on the other transparent insulating substrate, and in the case of a liquid crystal display panel, liquid crystal is sealed between these substrates. Furthermore, an auxiliary capacitor may be provided in parallel with the liquid crystal, in which case,
The auxiliary capacitor electrode is often formed in the lowest layer of the substrate on which the thin film transistor is fabricated.

[0003] In a thin film transistor matrix, each of the above-mentioned constituent elements is formed in layers with an insulating layer interposed therebetween. For example, an auxiliary capacitance electrode is provided on the surface of a transparent insulating substrate, a gate bus line is provided on the surface of the transparent insulating substrate, a gate bus line is provided on the surface of the transparent insulating substrate, a thin film transistor and a display electrode are provided on the insulating layer, and a thin film transistor and a display electrode are provided on the surface of the transparent insulating substrate. A drain bus line is provided via an insulating layer.

[0004] In order to obtain a large-sized television with high resolution, a large number of pixels are required, and each layer has thousands or tens of thousands of thin film transistors, gate bus lines, and drain bus lines. The greater the number of these elements and bus lines, the greater the possibility that defects will occur. Since it is inconvenient for the entire device to become unusable due to a small number of defects, conventionally each element or bus line has a redundant configuration, for example, an additional bus line is provided over the main bus line, and the main bus line Even if the bus line was disconnected, the entire bus line could be used by making use of the additional bus line.

[0005]

[Problems to be Solved by the Invention] However, in the conventional bus line redundant configuration, the main bus line and the additional bus line are placed in direct contact with each other, and there is a possibility that both of them may be disconnected. Ta. For example, additional bus lines and main bus lines may be placed one above the other, and in this case, even if the lower main bus line breaks during a certain manufacturing process, the If the additional bus line is not disconnected, the bus line can be used, but
As the manufacturing process progresses, stress acts on the bus line,
Additional bus lines above the main bus line that had been disconnected could also become disconnected at the same location. Conventionally, it has not been possible to repair the disconnection in such cases.

SUMMARY OF THE INVENTION An object of the present invention is to provide a thin film transistor matrix and a method for repairing the disconnection in which the disconnection can be repaired even in the latter stages of the manufacturing process.

[0007]

Means for Solving the Problems A thin film transistor matrix according to the present invention includes a plurality of thin film transistors, a first bus line connecting first electrodes of the thin film transistors, and a second bus line connecting second electrodes of the thin film transistors.
electrically floating at a position overlapping with at least one of the first bus line and the second bus line via an insulating layer. and a repair conductive layer provided in the state of.

The method for repairing a disconnection in a thin film transistor matrix according to the present invention, when at least one of the first bus line and the second bus line is disconnected, repairs the disconnection of the disconnected bus line by irradiating a laser beam. It is characterized in that parts on each side of the part are electrically connected to the repair conductor layer.

[0009]

[Function] In the above structure, the repair conductor layer is provided at a position overlapping the bus line where disconnection is likely to occur via the insulating layer, and is in an electrically floating state. Therefore, the bus line is usually not in electrical contact with the repair conductor layer. If the bus line is disconnected, for example, if a laser is irradiated to the parts on each side of the disconnected part of the disconnected bus line, the insulating layer at that part will melt and the conductive material of the disconnected bus line will become a repair conductor. comes into electrical contact with the layer. Therefore, an electrical path that bypasses the disconnection is formed by the repair conductor layer, and the disconnection can be repaired.

0010

Embodiment FIG. 4 is a diagram showing a liquid crystal display panel 10 of the present invention. The liquid crystal display panel 10 has an upper transparent insulating substrate 1
2, a lower transparent insulating substrate 14, and both substrates 12, 14.
and a liquid crystal 16 sealed between the two. An ITO solid electrode 18 is formed on the inner surface of the upper substrate 12, and the lower substrate 1
A thin film transistor matrix for image formation is provided on the inner surface of 4. An alignment film for the liquid crystal 16 may be provided on the inner surfaces of the upper substrate 12 and the lower substrate 14, and a color filter may be provided on the upper substrate 12. Further, the present invention is applicable not only to the liquid crystal display panel 10 but also to electroluminescence.

FIG. 5 shows an equivalent circuit of a thin film transistor matrix provided on the lower substrate 14, and FIG. 4 is a simplified enlarged view of one thin film transistor (TFT) 20 in the matrix. As shown in FIG. 4, the thin film transistor 20 includes a gate 22, a drain 24, and a source 26, to which a gate electrode 22a, a drain electrode 24a, and a source electrode 26a are attached, respectively. An ITO display electrode 28 is connected to the source electrode 26a. The thin film transistor 20 and the display electrode 28 are surrounded by an insulating layer 30. This insulating layer 30 is shown as a single-layer insulating layer in order not to complicate the drawing, but in reality, an insulating layer of SiO2 is formed in each step of laminating the thin film transistor 20 and the display electrode 28. be done.

Referring to FIGS. 4 and 5, the gate electrodes 22a of the thin film transistors 20 in each row are connected by a gate bus line 32, and the drain electrodes 24a of the thin film transistors 20 in each column are connected by a drain bus line 34. The gate bus line 32 and the drain bus line 34 are each formed of a metal film and are connected to a drive circuit (not shown). Further, the ITO auxiliary capacitance electrode 36 is connected to the lower substrate 1.
provided on the surface of 4. An insulating layer 38 is provided on the auxiliary capacitor electrode 36, and together with the display electrode 28 thereon, forms an auxiliary capacitor 40 of the liquid crystal 16 (FIG. 4). moreover,
A bus line repair conductor layer 42 is provided on the surface of the lower substrate 14 with ITO and covered with an insulating layer 38. This repair conductive layer 42 is provided in an electrically floating state at a position overlapping the drain bus line 34 with the insulating layers 38 and 30 interposed therebetween.

In the embodiment, when manufacturing the thin film transistor matrix, the auxiliary capacitance electrode 36 and the repair conductive layer 42 are simultaneously provided on the surface of the lower substrate 14, and then the gate bus line 32 is formed via the insulating layer 38. Then, the thin film transistor 20 and the display electrode 28 are formed through each constituent layer of the insulating layer 30, and then the drain bus line 34 is formed through the insulating layer 44. According to another manufacturing method, the vertical relationship between the gate bus line 32 and the drain bus line 34 can be reversed, and in this case, the repair conductor layer 42 is overlapped with the gate bus line 32 on the upper layer side. It is preferable to

FIG. 1 is a diagram showing a planar structure of this thin film transistor matrix with each insulating layer omitted. The display electrode 28 is located in a region surrounded by the gate bus line 32 and the drain bus line 34, and the thin film transistor 20 is located at one corner of the region. The auxiliary capacitance electrode 36 is located below the display electrode 28, extends in a cross shape, and extends continuously beyond the gate bus line 32 and the drain bus line 34 to other adjacent thin film transistor regions. The repair conductor layer 42 is provided so as to overlap the drain bus line 34 (via the insulating layer). The repair conductor layer 42 was manufactured from ITO at the same time as the auxiliary capacitance electrode 36, and as is clear from FIGS. 1 and 2,
The repair conductor layer 42 is not continuous with the auxiliary capacitor electrode 36,
That is, it is provided apart from the auxiliary capacitance electrode 36.

FIG. 3 shows a case where the drain bus line 34 is disconnected at a disconnection portion 50 in the thin film transistor matrix having the above structure. In FIG. 3, the drain bus line 34 itself has a redundant configuration, including a silicon n(+) layer 34a, a Ti layer 34b, and an A1
layer 34c. In FIG. 3, these silicon n(+) layer 34a, Ti layer 34b, and A1
The entire layer 34c has been cut.

When the drain bus line 34 is disconnected at the disconnection part 50, the parts 34x and 34y on each side of the disconnection part 50 of the drain bus line 34 are covered with a repair conductor layer 4.
Connect electrically to 2. In this case, when the laser is irradiated as shown by the arrow in FIG. 3, the drain bus line 3
4 and the repair conductive layer 42.
4 melts, and the material part 34p of the drain bus line 34
, 34q flow into the melted positions of the insulating layers 38, 30, and 44 and come into contact with the repair conductive layer 42. Thereby,
The material portions 34p and 34q of the drain bus line 34 and the repair conductor layer 42 form an electrical path that bypasses the disconnection portion 50, allowing the disconnection to be repaired.

[0017]

As explained above, the thin film transistor matrix according to the present invention has a plurality of thin film transistors, a first bus line that connects the first electrodes of the thin film transistors, and a second bus line that connects the second electrodes of the thin film transistors. A display electrode connected to the second bus line and the third electrode of the thin film transistor, respectively, is electrically connected to a position overlapping with at least one of the first bus line and the second bus line via an insulating layer. and a repair conductor layer provided in a floating state on the bus line, and when at least one of the first bus line and the second bus line is disconnected, each of the disconnected parts of the disconnected bus line is Since the side portion is electrically connected to the repair conductive layer, the disconnection can be repaired even in the latter stage of the manufacturing process.

[Brief explanation of the drawing]

FIG. 1 is a plan view of the thin film transistor matrix of FIG. 4 with an insulating layer omitted.

FIG. 2 is a plan view showing the bottom layer of FIG. 1;

FIG. 3 is a cross-sectional perspective view showing a case where the drain bus line is disconnected.

FIG. 4 is a sectional view of a liquid crystal display panel according to an embodiment of the present invention.

FIG. 5 is a diagram showing a thin film transistor matrix.

[Explanation of symbols]

10...Liquid crystal display panel 12, 14...Insulating substrate 16...Liquid crystal 20...Thin film transistor 22...Gate 24...Drain 26...Sauce 28...Display electrode 30, 38, 44,...insulating layer 32...Gate bus line 34...Drain bus line 34x, 34y...Parts on each side of the disconnection part 36...Auxiliary capacitance electrode 42...Repair conductor layer 50…Disconnection part

Claims (3)

[Claims] Claim 1: A plurality of thin film transistors (20);
A first bus line (32) connecting the first electrode of the thin film transistor, a second bus line (34) connecting the second electrode of the thin film transistor, and a third electrode connected to the thin film transistor, respectively. Display electrode (28
), and a repair part provided in an electrically floating state at a position overlapping with at least one of the first bus line and the second bus line (34) via an insulating layer (30, 38, 44). A thin film transistor matrix consisting of a conductor layer (42). 2. A repair conductor layer (4) comprising an auxiliary capacitance electrode (36) provided on a transparent insulating substrate (14).
2) is provided on the same layer as the auxiliary capacitor electrode on the transparent insulating substrate, apart from the auxiliary capacitor electrode, and an insulating layer (38) is provided on the repair conductor layer and the auxiliary capacitor electrode. The thin film transistor matrix according to claim 1, wherein the first bus line (32) or the second bus line (34) is provided on the insulating layer. 3. When at least one of the first bus line and the second bus line is disconnected, the parts (3) on each side of the disconnection part (50) of the disconnected bus line (34) are disconnected.
The parts on each side of the disconnected part (50) of the bus line (34) which was disconnected by irradiating laser to
34x, 34y) to the repair conductive layer (42).