JPH01167826A - Production of active matrix type liquid crystal display device - Google Patents

Abstract

PURPOSE:To lower the resistance of a bus line without complicating the production process and to decrease the film breakage by underlying steps by subjecting an image reversal photoresist to a negative type processing and positive type processing. CONSTITUTION:A conductive film 2 such as Ti film and a conductive film 3 such as Al film and an image reversal photoresist film 4 by a coating method are laminated on a substrate 1. A region 5 except an intersected region (C) of a gate electrode forming region (B) and a drain bus line in the gate bus line forming region (A) is then exposed and is baked. The other regions except the region A are then exposed and are subjected to the development processing to form the resist film 6. The exposed parts of the films 3, 2 are further removed by the similar processing. The film 6 is in succession exposed and developed and the resist film 6' covering the region A except the regions B, C is formed; thereafter, the exposed part of the film 3 and the film 6' are successively removed and the gate bus line of the laminated structure is formed.

Description

[Detailed Description of the Invention] [Summary] The present invention relates to a method for manufacturing an active matrix type liquid crystal display device, and a method for easily forming a gate bus line with a low resistance layered structure without causing film breakage. A first conductive film and a second conductive film are laminated thereon on a transparent insulating substrate, and an image reversal photoresist film is formed on the second conductive film by a coating method. 4 is formed, and then the image reversal photoresist film 4 is subjected to a first exposure to other regions of the gate bus line formation region except for the intersection between the portion where the gate electrode is to be formed and the drain bus line. Then, a reversal bake is performed, a second exposure is performed on other regions excluding the gate bus line formation region including the gate electrode formation portion and the intersection with the drain bus line, and then a development treatment is performed, and the 2
A resist film covering the entire gate bus line is formed by removing the exposed portion in the exposure, and the exposed portions of the second and first conductive films are removed using the resist film as a mask, and then the resist film is removed. A third exposure is performed on the front surface, and then a development process is performed to remove the unexposed part in the second exposure, and cover other areas of the gate bus line formation area except for the gate electrode formation part and the intersection part. Then, using the resist film as a mask, the exposed portion of the second conductive film is removed so that the gate electrode and the intersection portion are made of a single layer of the first conductive film, and the other portions are made of the first conductive film. and a step of forming a gate bus line having a stacked structure of a second conductive film.

[Industrial application field]

The present invention relates to a method of manufacturing an active matrix liquid crystal display device.

[Conventional technology]

The active matrix method, in which a thin film transistor (TPT) is provided for each pixel of a liquid crystal cell, has the advantage that display quality does not deteriorate even if the number of scanning lines increases.
It is beginning to be used in pocket TVs, etc.

Increasing the number of pixels using an active matrix method,
In order to make the screen larger, lowering the resistance of the pass lines is a major issue, and among the two intersecting pass lines, it is especially important to lower the resistance of the gate bus line formed under the semiconductor film, gate insulating film, etc. The big challenge is to make this possible.

In order to reduce the resistance of the gate bus line, it is sufficient to make the gate bus line thicker, but if the gate bus line is formed of a single Ti layer, thickening the Ti layer will cause the gate electrode part of the TPT and the gate bus line to become thicker. At the intersection with the drain bus line, the coverage of the gate insulating film deteriorates, and the existence of a step in the underlying layer causes film breakage, resulting in a problem of deterioration of breakdown voltage.

In order to solve this problem, the pass line has a two-layer structure, the lower layer is thin to improve the coverage of the metal layer laminated on top of it, and the metal layer laminated on top of this layer lowers the resistance. A method is conceivable, but this method has the problem of complicating the process and increasing manufacturing costs.

[Problem that the invention seeks to solve]

Conventionally, as mentioned above, when trying to increase the number of pixels and make the screen larger, film breakage is likely to occur due to the step of the gate bus line, and if you try to avoid this, the manufacturing process becomes complicated and the manufacturing cost increases. The problem is that it gets expensive.

It is an object of the present invention to provide a gate bus line with a low resistance layered structure that can be easily formed without causing film breakage.

[Means for solving problems]

In the present invention, a first conductive film and a second conductive film for forming a gate bus line are laminated on a transparent insulating substrate, and an image reversal photoresist is applied thereon. Of the area where the gate bus line is to be formed, other areas excluding the intersection with the drain bus line and the area where the gate electrode is to be formed are exposed, and then baking is performed to make the exposed area insoluble in the developer. do.

Next, the image reversal photoresist film is exposed to light in other areas except for the gate bus line formation area including the intersection and the gate electrode formation area, and then developed to remove the exposed area in this step. do.

This resist film covers the entire gate bus line formation region. Therefore, using this resist film as a mask, the exposed portions of the second and first conductive films are removed to form a gate bus line.

Further, the entire surface of the resist film is exposed to light to make the portion covering the intersection and the gate electrode portion soluble in a developer, and this portion is removed by development processing, and then the remaining resist film is used as a mask. By removing the exposed portions of the second conductive film, a gate bus line is obtained in which only the crossing portions and gate electrode portions are a single layer film, and the other portions have a laminated structure.

[For production]

In the present invention, when the image reversal photoresist is subjected to baking following exposure, the exposed area becomes insoluble in the developer, and when developed without baking after exposure, the exposed area becomes soluble, and any Taking advantage of the property that the unexposed area retains its original state even in the case of a resist film, it is possible to combine the negative processing of exposure-baking-development and the positive processing of exposure-development to improve the quality of one resist film. The patterning of the gate bus line is performed by sequentially changing the pattern.

That is, in the first exposure, the remaining regions of the gate bus lines except for the intersections and gate electrode portions are insolubilized by negative processing.

In the second exposure, areas other than the gate bus line forming area including the above-mentioned intersections and gate electrode portions are exposed, and development is immediately performed, so it is a positive type process, and the exposed portion of this step is removed. Therefore, the formed resist film covers the entire gate bus line including the gate electrode and the intersection.

By patterning the first and second conductive films using this resist film as a mask, a gate bus line having a --like laminated structure is obtained.

Since the portion of the resist film that covers the gate electrode portion and the intersection portion is an unexposed portion, it retains its original properties. Therefore, by exposing the entire surface of the resist film to light and performing a development process, the above two portions are removed and the conductive film at the intersection with the gate electrode portion is exposed. Therefore, by etching the second conductive film using this resist film as a mask, a gate bus line can be obtained in which the gate electrode and the intersection portion have a single layer structure, and the other portions have a laminated structure.

As described above in the present invention, gate bus lines having partially different configurations can be formed using one resist film by sequentially changing the pattern of a resist film by utilizing the properties of an image reversal photoresist.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1(a) to (1) and FIGS. 2(a) and (b).

First, as shown in FIG. 1(a), a first conductive film 2 made of Ti (
titanium) film and a second conductive film 3 on top of the AN(
Aluminum) film is formed.

Next, as shown in Figure 3), an image reversal photoresist film 4 is formed by a coating method, and prebater is performed on this.

Next, as shown in Figures (C) and (d), the image reversal photoresist film is coated with the area where the gate bus line is to be formed, at the intersection with the drain bus line and where the gate electrode is to be formed. The remaining area is exposed to light and then baked. This baking technique is called versatile baking. The satin-finished area in the figure shows the exposed area 5 in this step.

The processing in this step is a negative type processing, and the exposed area 5 is made insoluble in the developer. The remaining unexposed areas retain the original properties of the image reversal photoresist and can be further exposed to desired light in the future.

Next, as shown in FIGS. 5(e) and 5(f), the entire gate bus line forming region is masked, the remaining portion is exposed, and then a development process is performed. This process is a positive type process, and since the exposed area in this process is soluble in the developer, a resist film 6 is obtained that covers the entire area where the gate bus line is to be formed. This resist film 6 is composed of two parts: an exposed area 5 in the first exposure shown as a matte finish, and an unexposed area 7 in the second exposure shown as a white background.

Next, as shown in FIG. 3G, the exposed portions of the first conductive film 2 and the second conductive film 3 are removed using the resist film 6 as a mask. As a result, a gate bus line having a --like laminated structure is obtained.

Next, as shown in FIG. 6(h), the entire surface of the resist film 6 is exposed, followed by a development process.
The unexposed portion 7 is removed. As a result, a resist film 6' consisting only of the exposed portion 5 in the first exposure is obtained. This resist film 6° has a pattern that covers the area of the gate bus line excluding the above-mentioned intersection and gate electrode.

Therefore, using this resist film 6' as a mask, the exposed portion of the second conductive film 3 is removed to expose the surface of the underlying first conductive film 2. As a result, the intersection with the gate electrode made of only the first conductive film 2 becomes a single layer structure of only the first conductive film 2.

The perspective view of FIG. 2(a) shows the gate bus line GB obtained by the series of steps described above.

As shown in the figure, the intersection 8 between the gate electrode G and the drain bus line is made of a single layer of Ti, which is the first conductive film 2, and the other parts are made of a Ti film, which is the first conductive film 2, and a Ti film, which is the first conductive film 2. It has a laminated structure with the Aj2 film which is the conductive film 3.

Most of the gate bus line GB in this embodiment has a laminated structure, so the pass line resistance is small.Moreover, since the intersection 8 and the gate electrode C have a single layer structure, other films are formed thereon. In this case, the risk of membrane breakage due to the step is extremely small.

After this, a gate &f film such as a 3iN (silicon nitride) film is
i-edge) IL a-st: Source, source and drain electrodes made of an active semiconductor layer such as an H (amorphous silicon) film and a transparent conductive film such as an ITO film.

Then, pixel electrodes are formed to obtain an active matrix as shown in FIG. 2(b).

As is clear from the above description, in this example, by utilizing the properties of image reversal photoresist, a conductive film is formed while sequentially changing the pattern of one resist film by using both negative processing and positive processing. By etching, gate bus lines GB with partially different configurations can be created.
It could be formed using one resist film.

The gate bus line GB obtained in this example has a single layer structure at the intersection with the gate electrode G and the drain bus line DB and can be made thin, so it is formed to overlap these parts. Drain bus line DB
In the pixel electrode P, there is little risk of film breakage due to the step difference in the underlying layer, and therefore, the risk of failures such as disconnections, short circuits, or reductions in breakdown voltage is greatly reduced.

〔Effect of the invention〕

As explained above, according to the present invention, the resistance of the pass line can be lowered without complicating the manufacturing process, and there is no risk of disconnection, short circuit, or breakdown voltage deterioration due to film breakage caused by the step difference between the bases of each film. This significantly reduces the reliability and manufacturing yield of liquid crystal display devices.

[Brief explanation of the drawing]

Figures 1 (al to 1) are explanatory diagrams of one embodiment of the present invention, and Figures 2 (al and (1) are perspective views showing the above-mentioned embodiment. In the figures, 1 is a transparent insulating substrate, 2 is a a first conductive film;
3 is a second conductive film, 4 is an image reversal photoresist film, 5 is an exposed area, 6 and 6' are resist films, 7
8 is an unexposed portion, 8 is an intersection, G is a gate electrode, GB is a gate bus line, DB is a drain bus line, and P is a pixel electrode. Snake OD Ri

Claims (1)

[Claims] On a transparent insulating substrate (1), a first conductive film (2) and a second conductive film (3) are laminated thereon.
3) An image reversal photoresist film 4 is formed on the image reversal photoresist film 4 by a coating method, and then a portion of the gate bus line formation region where the gate electrode is to be formed intersects with the drain bus line. A first exposure is performed on other regions except for the gate bus line forming region including the gate electrode forming portion and the intersection with the drain bus line. Exposure is performed, and then development processing is performed to remove the exposed portion in the second exposure to form a resist film (6) covering the entire gate bus line (GB), and the resist film (6) is the second and first as masks;
The exposed portions of the conductive films (3, 2) are removed, and then a third exposure is performed on the front surface of the resist film (6), and a development process is performed to remove the unexposed portions (7) in the second exposure. A resist film (6') is formed to cover other areas of the gate bus line formation area excluding the gate electrode formation part and the intersection part, and then, using the resist film (6') as a mask, the second resist film (6') is removed. The exposed portion of the conductive film (3) is removed so that the gate electrode (G) and the intersection (8) are made of a single layer of the first conductive film (1),
A method for manufacturing an active matrix liquid crystal display device, characterized in that the other part includes a step of forming a gate bus line (GB) having a stacked structure of first and second conductive films (2, 3).