JPH0764108A - Semiconductor device and its production - Google Patents

Abstract

PURPOSE:To prevent the exposure of an Al film to a resist developer by an insulating protective film serving as protection at the time of working a source- drain film by forming source-drain electrodes into a laminated structure of a metallic layer and insulating layer. CONSTITUTION:The Al film is patterned and formed as gate electrodes 2 on one main plane of a transparent substrate 1 and a semiconductor layer is so formed as to overlap on a part of the gate electrodes via an insulating thin-film layer 3. An ITO film is then patterned and formed as pixel electrodes 4. A laminated layer 5a of Ti and Al as a metallic film and an SiNx film as an insulating film 6 are thereafter laminated and formed and are patterned and formed to obtain the source-drain electrodes 5. A TFT array substrate 7 is completed in such a manner. The gate insulating thin film 3 is preferably made to remain on the gate drawing out electrodes at this time. The metallic film 5a and the insulating film 6 are formed as the source-drain electrodes in such a manner, by which the insulating film 6 is acted as the protective film at the time of processing the source-drain film and the exposure of the Al to the resist developer is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device such as a thin film transistor (hereinafter abbreviated as TFT) for driving a liquid crystal display device and a method for manufacturing the same.

[0002]

2. Description of the Related Art A conventional method will be described below with reference to the TFT array forming process diagram of FIG. 3 and the schematic configuration diagrams of the TFT array and liquid crystal display device of FIGS.

In the TFT array, an Al film is patterned as a gate electrode 2 on one main surface of the transparent substrate 1 (see FIG. 3).
In steps 1 and 2), the semiconductor layer is formed so as to overlap a part of the gate electrode with the insulating thin film layer 3 interposed therebetween (steps 3 to 8 in FIG. 3). Then, an ITO film is patterned as the pixel electrode 4 (steps 9 and 10 in FIG. 3), and a metal laminated film 5a of Ti and Al to be the source / drain electrodes 5 is patterned (steps 11 and 12 in FIG. 3). Finally, the insulating protection film 6 is patterned (steps 13 and 14 in FIG. 3) to complete the TFT array 7 (see FIG. 4).

After the performance of the TFT array substrate 7 thus obtained is inspected, as shown in FIG.
The liquid crystal 9 is sandwiched and stuck between the T array substrate and the counter substrate 8 on which the transparent electrodes are arranged, and the subsequent TFT performance is inspected to obtain the liquid crystal display device 10.

As a process of assembling the liquid crystal display device, for dividing the substrate, chamfering, forming an alignment film on the TFT array substrate and the counter substrate, liquid crystal alignment control processing, printing a sealing material for bonding the both substrates, and controlling a gap between the substrates. The spacer material arrangement, the alignment and bonding of the both substrates, the liquid crystal injection and the injection port sealing, and the removal of the short ring for preventing the destruction of the TFT due to static electricity. Thereafter, TAB mounting is performed (see FIG. 6).

In these steps, the four steps surrounded by broken lines in the figure are concerned about substrate contamination.

Finally, by applying a voltage between the electrode connected to the conductor layer forming the TFT and the counter electrode (not shown), the liquid crystal is driven to display an image.

[0008]

In the TFT array, it is necessary to reduce the number of steps, improve the yield, and promote the cost reduction. By the way, one of the things that restrict the cost reduction is the photo process. In the above-mentioned TFT configuration, the insulating protection film, which is the final step, is caused by the inclusion of foreign substances made of a conductive material in the assembly process of the liquid crystal image display device.
This is an important step aimed at preventing a short circuit between the source electrode and the counter electrode, but this is one of the causes of the increase in the number of steps.
Further, in assembling the liquid crystal display device, the gate / source electrode lead-out portions have already been exposed in the TFT array process, so that there is a problem such as contamination during the assembling process.

In consideration of the above problems of the conventional TFT manufacturing method, the present invention can reduce the number of steps, and the semiconductor device and its manufacturing in which the lead-out portion of the gate / source electrode is not contaminated during the assembly process. It is intended to provide a method.

[0010]

According to the present invention, after a metal film and an insulating film are formed as source / drain electrodes, a resist mask having a source / drain electrode pattern is formed to form a source / drain electrode.
The insulating film of the drain electrode and the metal film are sequentially etched.

[0011]

By forming a metal film and an insulating film as the source / drain electrodes, the insulating film serves as a protective film when processing the source / drain film, and the Al film can be prevented from being exposed to the resist developing solution. .

Further, the photo process and the etching process can be reduced by collectively processing the metal film and the insulating film. Further, since the insulating film exists as a protective film on the source / drain electrodes in the same pattern, it is possible to prevent a short circuit between the source electrode and the counter electrode when the liquid crystal display device is assembled, and a liquid crystal image display device without uneven brightness. Can be secured.

Furthermore, the array process is terminated with the insulating thin film left on the external extraction electrode, and the residual insulating thin film is removed in the assembly process as a liquid crystal display device, so that the external extraction electrode is immediately before TAB mounting. Can be kept up to clean.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a process chart of forming a TFT array which is an embodiment of the present invention, and FIG. 2 is a T which is an embodiment of the present invention.
It is sectional drawing of FT.

In the TFT array of the present invention, an Al film is patterned as the gate electrode 2 on one main surface of the transparent substrate 1 as in the conventional example, and the semiconductor layer is the gate electrode via the insulating thin film layer 3. An ITO film is formed as a pixel electrode 4 so as to overlap with a part thereof.
After that, a laminated film 5a of Ti and Al is formed as a metal film, and a SiNx film is formed as an insulating film 6 (see steps 11 and 1 in FIG. 1).
2), pattern formation is performed to obtain the source / drain electrodes 5 (step 13 in FIG. 1). In this way, the TFT array substrate 7
Is completed (see FIG. 2).

At this time, it is desirable to leave the gate insulating thin film 3 on the gate extraction electrode. An insulator layer exists on the gate electrode 2 and the uppermost layer of the source / drain electrodes 5. Therefore, in the inspection before and after the assembly process of the liquid crystal display device, the probe needle is brought into contact with the metal film 5a of the gate electrode and the source / drain electrode 5 by penetrating the insulating layer. In this way, the performance of the TFT array is inspected. Then, the protective film is removed by etching when the TAB is mounted.

The source / drain electrode film and the insulating protective film may be formed continuously or individually. The photoresist may be negative or positive depending on the array structure and work environment. Further, in processing the source / drain electrode film and the insulating protective film, either wet etching or dry etching may be performed depending on the array configuration and the working environment.

Further, if the dry etching of SiNx, Ti and Al is carried out at the same time, the etching process can be simplified.

Further, in the present embodiment, the pixel electrode is provided in the pre-process of the source / drain electrodes, but the present invention is not limited to such a configuration.

[0021]

As is apparent from the above description,
According to the present invention, by forming the source / drain electrode with a laminated film of a metal film and an insulating film, the insulating protective film serves as a protective film during processing of the source / drain film, and the Al film is exposed to the resist developing solution. To be prevented. As a result, in a photoprocess using a positive resist, it is possible to avoid elution of Al due to a redox reaction between ITO and Al that occurs when the resist developing solution serves as an electrolytic solution.

Further, by collectively processing the metal film and the insulating film as the source / drain electrode film, the photo and etching steps can be reduced. Along with this, the steps of resist removal and substrate cleaning can be reduced.

Further, since the insulating film exists on the source / drain electrodes in the same pattern, it is possible to prevent a short circuit between the source electrode and the counter electrode when assembled as a liquid crystal display device,
It is possible to secure a liquid crystal image display device without uneven brightness.

In the TFT array, after the insulator layer on the gate / source electrodes is pierced by stylus to inspect the transistor function, the insulator layer on the gate / source electrode is removed at the time of assembly as a liquid crystal display device. Therefore, the electrode contamination in the assembling process can be prevented. As a result, the mounting lead-out electrode can be kept in a clean state until just before TAB mounting. Therefore, reliability after TAB mounting can be improved.

Further, in the present embodiment, the correlation between the laminated film of Al and Ti on the ITO film and the source / drain electrodes and the positive resist developing solution is described. Especially effective for metallic films with
It goes without saying that any metal film has the effect of simplifying the photo process.

[Brief description of drawings]

FIG. 1 is a process diagram of forming a TFT array according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a TFT configuration according to an embodiment of the present invention.

FIG. 3 is a process diagram of a conventional TFT array formation process.

FIG. 4 is a sectional view of a conventional TFT configuration.

FIG. 5 is a cross-sectional view of a configuration of a conventional liquid crystal display device.

FIG. 6 is an assembly / mounting process diagram of a liquid crystal display device.

[Explanation of symbols]

 1 Transparent Substrate 2 Gate Electrode 3 Insulating Thin Film Layer 4 Pixel Electrode 5 Source / Drain Electrode 5a Metal Laminated Film 6 Insulation Protective Film 7 TFT Array Substrate 8 Counter Substrate 9 Liquid Crystal 10 Liquid Crystal Display Device

Claims (2)

[Claims] 1. A gate electrode formed on one main surface of a substrate, a semiconductor layer formed so as to overlap a part of the gate electrode with an insulating thin film layer interposed therebetween, and a source / drain electrode. A semiconductor device, wherein the source / drain electrodes have a laminated structure of a metal layer and an insulator layer. 2. A step of forming a deposition pattern of a first metal film to be a gate electrode on an insulating substrate, a step of depositing a gate insulating film and a silicon semiconductor layer, and forming the silicon semiconductor layer in an island shape. A step of patterning, a step of forming a deposition pattern of a transparent electrode film, a step of depositing a second metal film to be a source / drain electrode and an insulating film in a laminated structure, and then using an etching mask of the source / drain electrode. And a step of subsequently etching the second metal film after etching the insulating film.