JPH0496023A - Active matrix circuit and its manufacture - Google Patents

Abstract

PURPOSE:To remedy a spot defect and a line defect by connecting an auxiliary electrode, which is formed at the same time with gate lines, to a gate electrode partially and arranging them in parallel to each other, and making the electrode cross a source electrode while they are insulated. CONSTITUTION:A metal layer of Mo, Cr, etc., is patterned in parallel to the gate lines so that the pattern of the gate lines G1 (2)... crosses the source lines S1, S2..., and the auxiliary electrode 8 is formed at the same time together with the gate lines. If a transistor(TR) T11 becomes defective, a gate part G is cut, a dot pad is connected to the drain pads of other dots through the auxiliary electrode 8, and a spot defect caused by the defect of the TR can be prevented. Then, if a short circuit is formed at the intersection of the gate line G1 and source line S1, the right and left X-marked parts of the intersection part A of the gate line G10 are cut. In this case, the auxiliary electrode 8 serves as a by-pass line for the cut place and the line defect is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an active matrix circuit such as a liquid crystal display (LCD) or an electroluminescence (EL) display using thin film transistors, and a method for manufacturing the same.

[Conventional technology]

FIGS. 6 and 7 show examples of thin film transistors according to the prior art. This thin film transistor is used in an active matrix circuit as shown in FIG. 5, and the like.

FIG. 5 schematically shows a planar addition of an active matrix substrate with gate lines Gl, G2 laterally on the substrate.
．． G3. ... run vertically, and source lines 31 . . . run vertically to intersect with these gate lines. S2. S3.
... are running and the intersection points form a matrix. Corresponding to each intersection, a drain pad Di1. D1
2. ...D21°D22...D31. D32・
... is placed. These drain pads form the driving poles of, for example, liquid crystal cells. An insulated gate field effect transistor TiJ is arranged between each drain pad and the corresponding source line Si (i=1.2.3...) and gate line Gj (J=1.2.3...). , the voltage of the source line St is applied to the drain pad Dij according to the signal of the gate line Gj.

These insulated gate field effect transistors T11 T1
2...T21. T22...T31°T32... are formed of thin film transistors using amorphous silicon as shown in FIGS. 6 and 7.

6 is a plan view showing an enlarged pattern of a part of the area in FIG. 5, and FIG.
FIG.

Figure 6-75! A method of manufacturing a thin film transistor according to the prior art will be described with reference to I.

A conductive film of Mo, Cr, etc. is formed on the glass substrate 1, and a gate electrode [! Pattern 2. The gate electrode 2 is connected to a storage capacitor electrode 2° or 't# for stabilizing the potential of the drain pad DiJ of another cell. However, there are cases where this storage capacitor electrode 2' is not provided. On top of that, SiN
, a gate insulating film 3 made of SiO2 or the like, and a semiconductor layer 4 made of amorphous silicon or the like are patterned into an island shape. Furthermore, a t[i metal layer is formed, a zero-order transparent conductive film such as ITO is formed to pattern the source/drain electrodes 5.6, and a train pad 7 is patterned to cover the storage capacitor S pole 2'. do. Finally, the low resistivity layer placed on top of the semiconductor layer 4 is etched to form a channel.

[Problem to be solved by the invention]

However, when such a thin film transistor is made into an active matrix as shown in FIG. 5, it has the following problems.

When manufacturing a thin film transistor, for example, the transistor Tl
If a defect such as a source-drain short circuit or a source-gate short circuit occurs in L, a point defect occurs in which the pixel driven by that transistor is either always ON or always OFF. Further, if there is a short circuit between lines at the intersection A of the gate line G1 and the source line S2, a line defect occurs.

Furthermore, if the gate line G1 is disconnected, the gate signal will not be transmitted to the gate lines after the disconnection, resulting in a line defect.

An object of the present invention is to provide an active matrix circuit for thin film transistors that can be corrected so that even if a transistor defect, a short circuit between a source line and a gate line, or a gate line disconnection occurs, it will not become a point defect or a line defect, and a method for manufacturing the same. The goal is to provide the following.

[Means to solve the problem]

In the present invention, the auxiliary electrode is formed at the same time as the gate line is formed. The auxiliary electrode is partially connected to the gate electrode, 2 is arranged parallel to each other, and intersects with the source line without insulation.
That is it. By adding an auxiliary electrode to the gate line, redundancy can be provided to the gate wiring. In other words, an abnormality in the gate line can be relieved by this auxiliary line. Moreover, the portion of this auxiliary t&8 that overlaps with the drain pad becomes a storage capacitor electrode.

[Effect]

If a short circuit occurs at the intersection of the gate line and source line during manufacturing, cut both ends of the shorted part of the gate line to insulate it from the gate line, bypass the cut part with an auxiliary line, and then Ensure continuity of the line.

Next, if the gate line is broken in the middle, the line defect can be repaired because the auxiliary electrode serves as a bypass circuit.

Further, if the transistor is defective, the gate portion of the transistor is cut off. In order to cut the wiring at an abnormal location, a method is used in which the location to be cut is destroyed by irradiation with a high-density energy beam such as a laser beam.

〔Example〕

FIGS. 1 and 2 show a planar structure and a cross-sectional structure of an embodiment of the active matrix of a thin film transistor according to the present invention. Reference numbers are given to parts that are equivalent or have the same function. 6 Add an auxiliary electrode 8 in parallel to the gate line so as to intersect the source line as shown in the pattern of the gate line Gl(2), . . . on the substrate, and pattern a metal layer such as MoCr. Auxiliary electrodes 8 are also formed simultaneously with the lines. Furthermore, a gate insulating film such as SiN, SiO2, etc., and a laminated semiconductor film of high resistance $a-3i-low resistivity a-3i are deposited on the channel part, source-gate intersection, and source-auxiliary electrode intersection of the transistor. The semiconductor film 4 is patterned into an island shape. Of course, in an actual active matrix, it goes without saying that regions other than those shown in the drawings are also formed to have a similar structure, and source lines 31, S2, etc. in the A1 layer, etc. ,, and drain to pole 6, IT
Drain pads Dll, D12. ．． ．． form. At this time, most of the auxiliary electrode 8 is made to overlap with the drain pad DOI of the pixel immediately above the pixel driven by the gate line (the dotted line part of the auxiliary electrode 8), so that the correction@pole 8 is It serves as a capacitance electrode for the pad DOI.

If a defect occurs in the transistor Tll during manufacturing, the gate part G of the transistor is irradiated with a laser beam to be cut, and the train pad is connected to the drain pad of another dot via the auxiliary if. By,
Point defects due to transistor defects can be prevented.

Next, if the intersection A of the gate line G1 and the source line S1 is short-circuited, the intersection A of the gate line G10 is
Cut the X-marked parts on the left and right sides.

In this case, the second auxiliary pole 8 serves as a bypass line at the cutting location, and line defects are prevented.

Furthermore, even if the gate line G1 is broken at the point X, the line defect can be repaired by using the auxiliary voltage #18 as a bypass path.

Next, a method for manufacturing a thin film transistor according to an embodiment of the present invention will be described with reference to FIG. 2, which is a cross-sectional view taken along line III-II in FIG. 1.

A conductive film is formed on a glass substrate 1, and a correction electrode 8 and a gate electrode 12 (Gl) are patterned.

A gate insulating film 3× of SiN, SiO2, etc. is formed thereon, and a semiconductor film 4 including a stacked layer of a high resistivity amorphous S1 film and a low resistivity amorphous Si film is formed to form the channel and source of the transistor. - Patterning is performed so that the semiconductor film 4 and the gate insulating film 3 remain in an island shape at the gate intersection and the source/auxiliary S-pole intersection. Furthermore, a metal layer is formed, and source/drain electrodes 5.
Pattern 6. And a train pad D1 which is a transparent electrode. D2... is formed. Finally, the low resistivity amorphous St film on the channel portion of the transistor is etched to form a channel.

Next, a second embodiment of the present invention will be described with reference to FIG.

The embodiment shown in FIG. 3 has a configuration in which all of the auxiliary electrodes 8 of the embodiment shown in FIG. 1 are connected in the lateral direction. Therefore, auxiliary electrode 8
and gate t&G1 (2>) are formed in a ladder shape. In this embodiment, the area of the storage capacitor @ pole part 8° (dotted line part) of the auxiliary electrode 8 is increased compared to that of the embodiment shown in FIG. Therefore, larger capacity can be obtained.

Furthermore, in the embodiment of FIG. 3, in the case of color display using three primary color pixels as shown in FIG. 4, display defects due to pixel defects can be minimized and made less noticeable.

It takes the following method.

Active matrix color display! In the fourth
As shown in the figure, pixels in a horizontal row are arranged from left to right in the order of R (red), G (green), and B (blue), and the rows below are B (blue), R (red), and G (green). ). If R
If a defect has occurred in pixel R10, the drain electrode part of the drain pad of R10 is cut with a laser beam to separate pixel R10, and then the Y part (2 locations) of the auxiliary electrode 8 shown in FIG. is melted by a laser beam to cause dielectric breakdown and short-circuit the auxiliary electrode 8, RIO, and the drain pad of R20. Furthermore, part 2 (5 locations) of Figure 4
is cut with a laser beam. By doing this, the defective pixel R10 becomes the pixel R2 driven by the common gate line.
Driven by 0. In other words, since the same gate line is driven with the same color (red) closest to it, defects become almost invisible. Note that the cross-sectional view of the embodiment in FIG. 3 is substantially the same as that in FIG. 2, so illustration thereof is omitted.

Although the present invention has been described above in accordance with the examples, the present invention is not limited to these examples. For example, various modifications,
It will be obvious to those skilled in the art that improvements, combinations, etc. are possible.

〔Effect of the invention〕

As explained above, according to the present invention, even if a pixel point defect due to a transistor defect or a line defect due to a short circuit at the intersection of a gate line and a source line or a disconnection of the gate line occurs during manufacturing, the auxiliary electrode By configuring a bypass circuit, point defects and line defects can be relieved.

Furthermore, in the case of a color display device, display deterioration due to pixel defects can be made less noticeable.

Moreover, since this correction electrode can be formed using the same material and the same photomask in the same process as the formation of the gate line, it can be formed without adding any special process or increasing the number of manufacturing steps.

Furthermore, the auxiliary electrode can also serve as a storage capacitor electrode, which has the excellent advantage of suppressing a reduction in the aperture ratio of the pixel.

[Brief explanation of the drawing]

Fig. 1 is a plan view of an embodiment of the present invention, Fig. 2 is a sectional view of the embodiment of Fig. 1, @3 is a plan view showing another embodiment of the present invention, and Fig. 4 is a plan view of the embodiment of the present invention. , FIG. 3 is a conceptual wiring diagram of an active matrix color display device according to an embodiment, FIG. 5 is a diagram schematically showing an active matrix circuit, FIG. 6 is a partial plan view of a conventional active matrix thin film transistor, and FIG. FIG. 7 is a cross-sectional view of FIG. 6. In the figure, the substrate gate electrode gate insulating film semiconductor film source electrode drain is connected to poles 1 to T13, T21 to T23° T31 to T33 insulated gate field effect transistors D11 to D13, D21 to D23° D31 to D33 drain pad (transparent electrode ) 01~G3 Gate line 81~S3 Source line 8 Correction electrode 2', 8' Storage capacitor electrode Patent applicant Stanley Electric Co., Ltd. Agent
Patent Attorney Keishibu Takahashi Figure 7 Cross-sectional view of conventional thin film I transistor

Claims (3)

[Claims] (1) In an active matrix in which a plurality of thin film transistors in which a gate electrode layer, a gate insulating film, a channel layer, and a source/drain electrode layer are stacked on a substrate, and a plurality of electrode pads driven by the thin film transistors are arranged, , an active matrix having an auxiliary electrode connected to the gate electrode layer and disposed in parallel with the gate electrode layer and intersecting the source electrode layer in an insulating state. (2) The active matrix according to claim 1, wherein the auxiliary electrode faces a part of the electrode pad with a gate insulating film interposed therebetween to form a capacitor. (3) In a method for manufacturing an active matrix having a plurality of thin film transistors by laminating a gate electrode layer, a gate insulating film, a channel layer, a source/drain electrode layer, and an electrode pad on a substrate, the gate electrode is laminated on the substrate. A method for manufacturing an active matrix including the step of simultaneously forming an auxiliary electrode connected to the gate electrode, parallel to the gate electrode, and intersecting the source electrode.