JPH06294967A - Production of liquid crystal display panel - Google Patents

Abstract

PURPOSE:To eliminate arc-shaped patterns at the internal angles of pattern which are heretofore unaviodable in a photolithographic stage by subjecting the prescribed patterns to exposing, then shifting the patterns so as to partly overlap the patterns and subjecting the patterns to reexposing. CONSTITUTION:The photomask patterns 1 of the parts where the arc-shaped pattern at the inside angles of the patterns are undesirable are composed of only the rectangular shapes in the stage for subjecting the negative type photoresist applied on a substrate to exposing. The reexposing is executed by stepping after the exposing is executed once and thereafter the photoresist is developed, by which the desired patterns are obtd. A line width increases in the overlap parts as the double exposed parts are overexposed if the overlap quantity of the first exposing and the second exposing is large. The constriction of the arc-shaped pattern parts arises if the overlap quantity is small. The adequate overlap quantity is the quantity at which the arc-shaped patterns generated as latent images are negated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing an active matrix type liquid crystal display panel.

[0002]

2. Description of the Related Art Liquid crystal display panels have been put into practical use, and nowadays high quality and high density are desired. This is possible in an active matrix liquid crystal display panel.

In the active matrix type liquid crystal display panel, active elements and pixels are arranged in the liquid crystal display portion in an amount of 50,000 to 200,000, and the dimensional accuracy of each must be strictly controlled.

Moreover, in a high-density active matrix type liquid crystal display panel for improving display image quality and an active matrix type liquid crystal display panel having a small display area such as a viewfinder, a wiring pattern, an element area and a pattern are formed. There is a limit to miniaturization of dimensions such as alignment accuracy between layers.

For these reasons, it is desirable to form a photoresist having a pattern accuracy faithful to the photomask.

For this reason, the patterning technology is required to be more sophisticated, but the liquid crystal panel manufacturing apparatus is sufficiently capable of handling from the experiment to the mass production due to the restrictions such as the enlargement of the substrate area and the variation of the substrate material. A device with excellent performance is not currently available.

In a semiconductor integrated circuit manufacturing process, a method has been proposed in which a multi-layered resist is used to deal with the deformation of a pattern caused by the reduction in contrast of an exposure apparatus. However, this multi-layer resist method is difficult to use for manufacturing a liquid crystal panel and has not been put to practical use because the control of the resist film thickness is very strict and the material is expensive.

Moreover, in the semiconductor integrated circuit manufacturing process, the general reduction projection exposure method is also required to have a large area. For this reason, the ½ reduction is only partially used, and most of them are the same-magnification exposure method. For this reason,
Photomask accuracy also affects pattern accuracy.

In particular, regarding the arc-shaped pattern generated in the inner corner area of the pattern, the finer the pattern, the more it affects the alignment margin and the aperture ratio of the liquid crystal display panel.

Therefore, the arc-shaped pattern of the inner corner of the pattern is an obstacle for manufacturing a high-density, high-definition and high-quality liquid crystal display panel, but there is currently no method for removing it.

An object of the present invention is to solve an arc-shaped pattern generated in a pattern inner angle, which cannot be achieved by a liquid crystal manufacturing apparatus, which is an obstacle in advancing miniaturization, without using a special process such as a multilayer resist. A method of manufacturing a high quality active matrix type liquid crystal display panel is provided.

[0012]

In order to achieve the above object, the method described below is adopted as the method of manufacturing the liquid crystal display panel of the present invention.

The method for producing a liquid crystal display panel of the present invention is a method for etching and patterning a metal film, an insulator film or a semiconductor film using a negative photoresist, and the negative photoresist is exposed to light at a predetermined level. After exposing the pattern (1), the pattern is shifted so that a part of the pattern is overlapped, and then exposed again, and then the negative photoresist is developed.

[0014]

According to the manufacturing method of the present invention, in the step of exposing the negative type photoresist coated on the substrate, the photomask pattern of the portion where the arc-shaped pattern of the inner corner of the pattern is not preferable is formed only by the rectangle and is exposed once. It is characterized in that a desired pattern is obtained by performing a post-step, exposing again, and then developing.

By exposing a rectangular pattern in steps and overlapping the patterns, the arc-shaped pattern at the inner corner of the photoresist pattern is remarkably reduced, and a high-density and high-definition active matrix liquid crystal display. Enables panel manufacturing.

[0016]

Embodiments of the method of manufacturing a liquid crystal display panel according to the present invention will be described below with reference to the drawings.

A case where a lattice-like black matrix pattern 1 having a width of 10 μm as shown in FIG. 1 is manufactured will be described as an example.

Chromium (Cr) used as a black matrix on a glass substrate at a film thickness of 100 nm,
It is formed using a sputtering method.

Thereafter, a negative photoresist having a viscosity of 35 cp is formed to a thickness of 1.2 μm by a spin coating method under the conditions of a rotation speed of 2500 rpm and a time of 30 seconds. After that, baking treatment is performed using a hot plate at a temperature of 110 ° C. for 90 seconds.

Next, as shown in FIG. 2, a first exposure is performed using a photomask having a rectangular pattern.

In the photomask, the line width of the portion corresponding to the vertical line 1a of the black matrix pattern 1 of FIG. 1 is 5.5.
μm.

On the other hand, the size of the portion corresponding to the horizontal line 1b of the black matrix pattern 1 is 10 μm, which is the same width as the design value, but the width of 5 μm is maintained without contacting the vertical line 1a. It is arranged like an island.

An arc-shaped pattern of about 0.2 μm is attached to the corner region of the rectangular portion of the photomask through which light is transmitted.

Using a photomask having a pattern as shown in FIG. 2 as a photoresist on a glass substrate,
Ultraviolet rays are irradiated for 1.5 seconds with an exposure energy of 11 mW / cm ² using a 1 × stepper.

As a result, a latent image 2 having the same shape as the photomask pattern is formed in the photoresist as shown in FIG.

The corner portion of the rectangular pattern at this time is
As shown in FIG. 3, an arc-shaped pattern of about 0.6 μm, which is formed by performing the development process as it is, is formed.

Next, the glass substrate is laterally moved to 4.5 μm.
Then, the second exposure is performed under the same conditions as those described above. As shown in FIG. 4, even in the second exposure, a 0.6 μm arc-shaped pattern is formed as a latent image in the corner portion of the pattern.

In the present embodiment, the overlapping dimension between the first exposure and the second exposure is such that one of the patterns has an arcuate pattern like the abutting portion of the vertical line 1a and the horizontal line 1b. If there is 0.5 μm, horizontal line 1b
When both patterns have an arc-shaped pattern as in each other, it is 1 μm.

As a result, 0 ..
The 6 μm arc-shaped patterns are overlapped with each other, and developed for 1 minute with a dedicated developer for negative-type photoresist, and the negative-type photoresist pattern obtained through the rinsing process becomes a right angle because the arc-shaped pattern at the inner corner of the pattern disappears. Furthermore, the straight line pattern becomes a straight line.

The black matrix pattern 1 thus obtained has no arcuate pattern at the corners.

When an active matrix type liquid crystal display panel of 1 inch or less, which is used for a viewfinder or the like, is manufactured by using the method described above, the aperture ratio is improved by 1% and a bright panel can be realized.

When the amount of overlap between the first exposure and the second exposure is large, the double exposure portion is overexposed and the line width becomes thick at the overlap portion. When the overlap amount is small, the arc-shaped pattern portion is formed. Constriction occurs. The appropriate overlap amount is the amount by which the arc-shaped pattern generated in the latent image is canceled.

Next, a manufacturing method according to the second embodiment of the present invention will be described with reference to FIGS.

A lower electrode pattern 4 having a width of 2 μm is projected on a wiring pattern 3 having a width of 10 μm as shown in FIG. 5A, and an upper electrode pattern 6 having a width of 2 μm as shown in FIG. An example will be described in which an element that has a shape protruding from the pixel electrode 5 and is stacked with an insulating layer interposed is formed.

As shown in FIG. 5B, the overlapping area 7 of the lower electrode pattern 4 and the upper electrode pattern 6 is
The area 7 error is managed very strictly because it controls the characteristics as an element.

The arc-shaped pattern of the inner angles shown in FIGS. 5A and 5B is about 1 μm, and an alignment margin of ± 1.5 μm is considered so that the area 7 of the element is not changed even if an alignment error occurs. Then, the length of the protruding patterns of the lower electrode 4 and the upper electrode 6 needs to be 7 μm.

In this embodiment, a photomask as shown in FIG. 6A is used. The wiring pattern 3a has a width of 8 μm, and 2 μm is provided at a position 1 μm away from the wiring pattern 3a.
A lower electrode pattern 4a having a width of m and a length of 5 μm is arranged.

Using a photomask having such a pattern, tantalum (Ta) serving as a lower electrode was formed on a glass substrate to a thickness of 200 nm by a sputtering method, and a negative photoresist was used as in Example 1. Are formed and exposure is performed.

The exposure conditions may be exactly the same as in Example 1, but the amount of movement of the glass substrate during the second exposure is 2 μm.
And

The overlap amount of the wiring pattern 3a is 6 μm, but there is no problem in terms of the pattern.
Reliable resist formation by double exposure is convenient.

The overlap amount of the lower electrode pattern 4a is 3 μm, and the line width is slightly thicker than that of the pattern formed by one exposure.

However, the increase amount of the line width is uniform, and is a sufficiently small value even compared with the amount of thinning of the line width due to under-etching which occurs in the etching process of the next step. Therefore, it cannot be a factor that deteriorates the quality such as the characteristics of each element or the variation as a whole.

Wiring pattern 3a and lower electrode pattern 4a
As shown in the first embodiment, the connection portion with and can form a pattern without an arcuate pattern of an inner angle by an overlap of 1 μm.

By eliminating the arcuate pattern at the inner corner of the pattern, the upper electrode pattern 6 is expected to have an error due to alignment up to the point of contact with the wiring pattern.
The length of the lower electrode pattern 4 can be shortened by about 1 μm.

Using the negative photoresist pattern thus obtained, tantalum (Ta) is etched by the reactive ion etching method, and the photoresist is peeled off.

Next, tantalum (Ta) is anodized to form an insulating film layer, and then indium tin oxide (ITO) to be an upper electrode pattern is formed to a thickness of 200 nm by a sputtering method.

As in Example 1, a negative photoresist was applied and exposed, but the photomask had a shape as shown in FIG. 6B.

That is, the pixel electrode 5a has a pattern smaller than the design value by 2 μm in the moving direction. An upper electrode pattern 6a having a width of 2 μm and a length of 5 μm is arranged at a position 1 μm away from the pixel electrode 5a.

Example 1 using such a photomask
The first exposure and the second exposure are performed under the same conditions as. Second
The exposure is performed by moving the glass substrate by 2 μm in the vertical direction.

Thereafter, the pattern obtained by development is a pattern having no arc-shaped pattern at the inner angle as shown in the example of the lower electrode pattern 4 described above, and the length of the upper electrode pattern 6 can be shortened by approximately 1 μm. it can.

Next, after heat-treating the negative photoresist, the ITO is etched with an etching solution composed of an acid containing iron chloride to remove the negative photoresist.

Using the device thus obtained, a process for producing a normal liquid crystal display, that is, an alignment film coating process, an alignment treatment process by rubbing, a bonding process with a counter substrate which has been similarly treated, An active matrix type liquid crystal display panel is completed through a liquid crystal injection process and a sealing process.

The active matrix type liquid crystal display panel manufactured by the methods shown in the first and second embodiments of the present invention has a very bright and good display quality because the aperture ratio can be made large.

In the first and second embodiments of the present invention, the exposure is performed twice with the first exposure and the second exposure being shifted.
It is possible to obtain a pattern having no arc-shaped pattern at the inner corner of the pattern even when the exposure is performed with a shift more than once.

Further, in the above-described first and second embodiments of the present invention, the photomasks having the same pattern are shifted and exposed, but the photomasks having different patterns are also used for exposure. It is possible to obtain a pattern having no arcuate pattern at the inner corner of the pattern.

[0056]

As is apparent from the above description, according to the present invention, it is possible to eliminate the arc-shaped pattern of the pattern inner angle which cannot be avoided in the photolithography process.

As a result, the aperture ratio can be improved by reducing the areas of the black matrix and the active element portion of the liquid crystal display panel. Furthermore, it is possible to manufacture a bright and high-quality liquid crystal display panel even for a high-density and high-definition active matrix liquid crystal display panel.

[Brief description of drawings]

FIG. 1 is a plan view showing a method of manufacturing a liquid crystal display device according to a first embodiment of the present invention.

FIG. 2 is a plan view showing the method of manufacturing the liquid crystal display device according to the first embodiment of the present invention.

FIG. 3 is a plan view showing the method of manufacturing the liquid crystal display device according to the first embodiment of the present invention.

FIG. 4 is a plan view showing the method of manufacturing the liquid crystal display device according to the first embodiment of the present invention.

FIG. 5 is a plan view showing the method of manufacturing the liquid crystal display device according to the second embodiment of the present invention.

FIG. 6 is a plan view showing the method of manufacturing the liquid crystal display device according to the second embodiment of the present invention.

[Explanation of symbols]

 1 Black matrix pattern 2 Latent image 3 Wiring pattern 4 Lower electrode pattern 5 Pixel electrode 6 Upper electrode pattern

Claims (1)

[Claims] 1. In a manufacturing method of etching and patterning a metal film, an insulator film or a semiconductor film using a negative photoresist, the negative photoresist is exposed by exposing a predetermined pattern and then exposing the pattern. A method of manufacturing a liquid crystal display panel, which comprises exposing the photoresist again so that the portions overlap each other, and then developing the negative photoresist.