JPH02223928A - Defect relieving method - Google Patents

Abstract

PURPOSE:To correct defects without exerting the influence of contamination, etc., on other parts by electrically insulating a defective TFT simply by partially applying heat to a contact part. CONSTITUTION:A semiconductor film consisting of silicon, etc., or a metallic conductive film 2 consisting of aluminum, etc., is formed on an insulating substrate 1 and after an interlayer insulating film 6 is formed thereon, contact holes are opened to a prescribed pattern. The conductive film 2 and a conductive film 8 of an oxide system are electrically conducted if the conductive film 8 is deposited thereon. However, the oxygen in the conductive film 8 of the oxide system diffuses into the conductive film 2 and the insulating film 9 of the oxide system, such as SiO2 and Al2O3 is formed at a contact boundary 9 if heat is partially applied by a laser beam, etc., to the contact regions 9 and 116 of the conductive film 2 and the conductive film 8 of the oxide system. The conductive film 2 and the conductive film 8 of the oxide system are thereby insulated. The picture element of the defective TFT part is the defect of a normally lighting abnormal lamp if the transparent conductive film 117 for driving the picture element is insulated from the drain region 116 in such a manner. The defect of the panel is, thus, inconspicuous.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an active matrix substrate used in a liquid crystal display device and a method for relieving defects in semiconductor elements.

[Conventional technology]

In recent years, thin film i-transistors (hereinafter referred to as TPT) have been developed on insulating substrates.
Research is being actively conducted to form the This technology is important for applications such as active matrix panels that realize thin displays using inexpensive insulating substrates such as glass. In this application, a transmissive display panel structure can be obtained by using a transparent electrode as the display electrode of the 9 display panel and sealing liquid crystal between the opposing transparent electrodes.

FIG. 2(a) shows an external view of a TPT constituting a transmissive display panel. In the drawing, 201 is the source line, 20
2 is a gate line, 203 is a gate electrode, 204 is a polycrystalline silicon thin film, 2o5 is a source contact, and 206 is a drain contact.

207 is a liquid crystal drive electrode which is a transparent conductive film. Terminals are formed on the source line and the gate line outside the pixel to connect them to an external drive circuit and an electrical property measuring device.

Next, a cross-sectional view of the broken line part in FIG. 2(a) is shown in FIG. 2(b).
Shown below. In the drawing, 211 is an insulating substrate, 212 is a source diffusion region doped with impurities in polycrystalline silicon,
213 also has a drain diffusion region formed in the same manner as 212;
14 is a gate oxide film.

215 is a gate electrode, 216 is an insulating film between the eyebrows, 217 is a saucepan, and 218 is a liquid crystal drive electrode.

The gate electrode and source line or source diffusion region of the TPT are insulated by a glabella insulating film with a thickness of about 1 micron and a gate oxide film with a thickness of several tens to hundreds of microns. Leakage between diffusion regions is likely to occur.

For example, during the process, foreign matter (dust, fluff, etc.)
If TPT is further deposited on the polycrystalline silicon, gate oxide film, etc. on the substrate at the TPT portion, leakage occurs due to a short circuit between the polycrystalline silicon gate electrodes. The same applies to uneven rubbing. In particular, if it gets on the gate oxide film, it will almost always result in a very large leak. Also.

Leakage may also occur due to damage to the gate oxide film due to minute foreign matter or static electricity that is difficult to determine from the outside.

When leakage occurs between the source diffusion region and the gate electrode due to the above-mentioned causes, an electrical connection is made thereto. This results in leakage between the source line and gate line. Due to the leakage between the lines, the gate line signal and the source line signal are mixed, and when the display panel 9 is turned on, it is visually confirmed as a defect in the source/gate line. Further, when leakage occurs between the source diffusion region and the drain diffusion region, the pixel connected to the TPT in the portion where the leakage occurs is visually confirmed as a defect.

The conventional defect repair method described above will be explained with reference to FIG.

FIG. 2(a) shows a TPT with leakage between the source diffusion region and the gate electrode, and is before correction.

(c) and (d) are after correction. In (C), the polycrystalline silicon layer connecting the source diffusion region and the source line is cut (fused) in a non-contact manner using a laser repair device or the like. In the case of (d), a defect repair method has conventionally been used in which a similar method is used to cut the conductive thin film connecting the gate electrode and the gate line. Note that related defect repair methods of this type include, for example, Japanese Patent Application Laid-Open No. 58-171.
845, No. 845.

[Problem to be solved by the invention]

In the above conventional technology, when a defect occurs, the polycrystalline silicon layer between the source diffusion region and the source line or the conductive 7a film connecting between the gate electrode and the gate line electrode is fused using a laser or the like, and the semiconductor film, metal thin film, etc. contaminate. There were problems such as short circuits occurring in new parts.

The present invention eliminates this problem, and its purpose is to correct defects that affect other parts than the defective part.

[Means to solve the problem]

In order to achieve the above purpose, if a defect occurs, the part to be electrically disconnected should have a structure in which a contact area between a metal film and an oxide-based conductive film or a contact region between a semiconductor film and an oxide-based conductive film is formed. .

If a defect occurs, heat can be applied locally using a laser beam or the like.

[Effect]

Oxide-based conductive films come into contact with semiconductor films such as silicon or metal films such as aluminum, and when heat is applied, S is generated at the contact interface.
An oxide-based insulating film such as iO, AQ, 03, etc. is formed.

Thereby, the defective part becomes electrically insulated, so that the f#, electrically shorted defect is corrected. Also 1
According to the invention, an oxide thread conductor, ff1, is provided in the contact area.
Since heat of about 300 to 500'C, which is enough to react with 1000 ml of oxygen, is only partially applied, there is no effect of contamination on other areas.

〔Example〕

The following two embodiments of the present invention are shown in FIGS. 1 and 3.

This will be explained with reference to FIG. 4. FIG. 1(b) shows the source contact region 115. FIG. 3 is a plan view of a thin film transistor having leakage between drain contact regions 116; If a signal voltage is constantly applied to the pixel driving transparent conductor 11.117 due to a short circuit between the source contact l[115 and the drain contact region 116]9, the pixel with a defect in the display panel will always have a white spot. displayed as a defect. In this case, if the transparent conductive film 117 for pixel driving is removed from the drain region 116, the pixels in the defective TFT section will always be defective as a pair of abnormal points, and the defect will not be noticeable as a panel. Transparent conductive film 1 in this case
The insulation method of No. 17 will be explained with reference to FIG. 1(a). Figure 1 (
1(a) is a cross-sectional diffusion view of the drain contact region 116 of FIG. 1(b). A semiconductor film such as silicon or a metal conductive film 2 such as aluminum is formed on an insulating substrate 1, and after an interlayer insulating film 6 is formed thereon, contacts 1 to holes are opened in a predetermined pattern. After that, indium oxide, tin oxide,
When the oxide-based conductive film 8 such as indium or tin oxide is deposited, the conductive film 2 and the oxide-based conductive film 8 become electrically conductive. However, when heat is applied partially to the contact area 9.116 of the conductive film 2 and the oxide-based conductive film 8 using a laser beam or the like, oxygen in the oxide-based conductive film 8 diffuses into the conductive film 2, and the contact area 9 with Si, 02 and AQ20. Oxide-based insulating film 9 such as
is formed to insulate the conductive film 2 and the oxide-based conductive film 8. Here, the conductive film 2 corresponds to the polycrystalline silicon film 314 of the drain contact region 116, and the oxide conductive film 8 corresponds to the pixel driving transparent conductive film 3.17.

A second example is shown below. Figure 3 shows the source diffusion region 3.
05. 3 is a plan view of a thin film transistor having leakage between gate electrode regions 303. FIG. If a wiring-based conductive film is used as the source wiring 301 in the source region 305 and heat is applied partially to the contact region 305 using a laser or the like as in the first embodiment, an oxide-based insulating film is formed in the source contact region 305. A source line 301 and a gate line 3 are formed.
By insulating 02, line defects can be corrected.

A third example is shown below. Figure 4 shows the source diffusion region 4.
09. 3 is a plan view of a thin film transistor having leakage between gate electrode regions 403. FIG. In this embodiment, the source wiring 4
This is a case where a low-resistance conductive film such as aluminum is used for 01. Source wiring 40] and TFT source diffusion region 4
Contact hole is opened in 09, and oxide-based conductive film 4 is formed.
Electrical continuity is established at 08. Source diffusion region 40
9° In the thin film 1 and transistor having leakage in the gate electrode region 403, heat is applied partially to one or both sides of the contact regions 305 and 306 using a laser or the like to form an oxide-based insulating film at the contact region interfaces 305 and 306. However, line defects can be corrected by insulating the source line 401 and gate line 402.

〔Effect of the invention〕

According to the present invention, when a defect occurs in TI"T, the TP
Since the defective TPT can be electrically isolated by simply applying heat to the contact area 1 between the T and the source and gate lines, the defect can be repaired without contaminating other parts. be. Furthermore, it becomes possible to convert line defects into pixel defects due to source and gate line leakage. Therefore, there are excellent effects such as improving the yield of display panels and shortening the repair time.

[Brief explanation of the drawing]

FIGS. 1(a) and 1(b) show hair of a first embodiment of the present invention. The second (a) is 'g1. Top view of the crotch transistor, 2nd
Figure (b) is a sectional view taken along the broken line in Figure 2 (a). FIGS. 2(C) and 2(d) are external views after defect correction by the conventional method. FIG. 3 shows a second embodiment according to the invention. FIG. 4 shows a third embodiment according to the invention. 1.211...Insulating substrate, 2,212,213...
・Source/drain diffusion region, 113, 203° 215
．． 233,303,403--Goo 1-electrode. 112.202,302,402...gate line,
1.14,204,304,404...polycrystalline silicon thin film, 115,205,305°405.409...
・Source contact, 6°216... interlayer insulating film, 2
15...Gate electrode. 116.206,306,406...Drain contact, 8,117,207,218°307.407,
408...Transparent conductive film, ], ]-2201, 217
, 301, 401... Source line, 9... Oxide-based insulating film.

Claims (1)

[Claims] 1. A leakage current flows between the source equivalent region and the gate electrode of each thin film transistor arranged in a matrix on an insulating substrate, and leakage current flows between the source line and the gate line electrically connected to the gate electrode in terms of the source diffusion amount and the gate electrode. In a thin film transistor in which leakage has occurred, a contact region with an oxide-based conductive film is formed in the source diffusion region, and the contact region is partially heated to insulate between the source line and the gate line. and how to remedy defects.