JPH0289003A - Formation of color filter - Google Patents

Abstract

PURPOSE:To easily and accurately form the color filter by forming light shielding parts to a transparent substrate exclusive of the parts where patterns of desired colors are disposed and aligning the light shielding parts on the transparent substrate on which a photoresist layer for coloration is formed and the light transmission parts of a photomask. CONSTITUTION:A black matrix 2 to be disposed between the colored patterns is formed on the substrate 1. The photoresist 3 for coloration of the 1st color, for example, red is applied thereon and thereafter, the photomask 4 corresponding to the 1st color is registered to the surface on the side opposite to the surface of the substrate 1 coated with the photoresist 3 at the specified gap maintained therebetween. The desired colored patterns are formed by repeating the position setting, exposing and developing of the photomask. The color filter is easily and accurately formed in this way.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for forming a color filter.

[Conventional technology]

Color filters are widely used in liquid crystal color display devices, color solid-state image pickup devices, etc., and one way to form them is to coat gelatin on a transparent substrate such as glass.
By repeating the process of applying a coloring photoresist such as a colored photoresist, exposing the surface with a photomask in close contact with the surface coated with the coloring photoresist, and then developing, a desired color such as red, green, blue, etc. can be obtained. A contact exposure method is known to form a colored pattern, and another method is to place a photomask on a colored photoresist with a certain gap between them without making it come into close contact with the photoresist, and then develop the photoresist after exposure. A proximity exposure method is also known, in which a desired colored pattern is formed by repeating exposure.

[Problem to be solved by the invention]

However, the following problems arise with the contact exposure method. In other words, in contact exposure, it is necessary to use a number of photomasks corresponding to the colored patterns to precisely match the arrangement of each color. After aligning the target board with a certain gap,
I try to keep them close together. However, during this close contact, positional deviation may occur, making it impossible to achieve highly accurate positioning. For this reason, the total pitch of the colored pattern on the substrate to be exposed is slightly off, and for example, when assembling a cell through the liquid crystal layer, the relative positional relationship will be off, and the exact pitch on the display will be off. In some cases, colors may not be obtained or the colors may be uneven across the display. In addition, in the case of the contact exposure method, the photomask is placed in close contact with the photoresist surface multiple times.
Due to exposure, foreign matter tends to adhere to the photoresist surface and the photomask.For this reason, the parts of the photoresist surface where the foreign matter has adhered are not exposed to light, and after development, they become defects and cannot be used as color filters. There was also the problem that it could not withstand use.

In addition, with the proximity exposure method, the problem of foreign matter adhering to the contact exposure method is alleviated, but when it comes to alignment between the photomask and the substrate to be exposed, the contact exposure method does not cause any misalignment, but it does not have high accuracy. In order to determine the position, it is necessary to monitor with a television camera or a laser scanning method, which makes the device complicated. Furthermore, in the case of the proximity exposure method, a certain gap is set between the photomask and the substrate to be exposed. It is very difficult to set a constant gap between them at any position, and as a result, variations in size tend to occur in the colored pattern printed on the substrate to be exposed. Furthermore, due to the constant gap, there was also the problem that fine patterns could not be formed using colored photoresists with poor resolution.

The present invention is intended to solve the above-mentioned problems, and an object of the present invention is to provide a method for forming a color filter that can easily and accurately form a color filter.

[Means to solve the problem]

In order to achieve the above object, the method for forming a color filter of the present invention includes coating a colored photoresist on a transparent substrate, exposing it to light through a photomask from the side opposite to the surface of the colored photoresist layer, and then, In a method for forming a color filter in which a color filter is formed by repeating a developing step, first, a light-shielding portion is formed on the transparent substrate other than a portion where a pattern of a predetermined color is arranged,
After that, the coloring photoresist layer is formed on the surface of the transparent substrate opposite to the coloring photoresist) J1 surface,
By providing a photomask with a light-transmitting part corresponding to a pattern of each color, maintaining a certain gap, and aligning the light-shielding part with the light-transmitting part of the photomask, each coloring photoresist layer surface is exposed. , development is performed.

[Action and effect of the invention]

According to the present invention, the arrangement of all colors is first determined by the light-shielding part, that is, the black matrix, so even if the light-transmitting part of the photomask is slightly misaligned with the color pattern, the accuracy of the colored pattern obtained will change. There isn't.

Furthermore, by exposing through a photomask from the side opposite to the coloring photoresist layer, it is possible to minimize the adhesion of foreign matter to the surface of the coloring photoresist layer, and by keeping a certain gap between the photomask and the substrate. Therefore, there is very little foreign matter adhering to the photomask.

Further, although a photomask for each color is used as a photomask, since the black matrix serves as the final photomask, high resolution comparable to that of the contact exposure method can be obtained.

As described above, according to the present invention, it is possible to extremely easily align the photomask, and it is possible to easily and accurately form a color filter with extremely few defective parts. Furthermore, in terms of resolution, it is possible to achieve a high resolution comparable to that of contact exposure, and it is also possible to use photoresists with somewhat poor resolution.

〔Example〕

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

The following examples will be described assuming that a colored pattern as shown in FIG. 1 is formed. In FIG. 1, RlG and B represent a red pattern, a green pattern, and a blue pattern, respectively.

In the present invention, first, as shown in FIG. 2, a black matrix 2 arranged between colored patterns is formed on a substrate 1 such as glass. The black matrix 2 can be formed using a Cr thin film, but since the total pitch of the black matrix pattern controls the pitch accuracy of each color pattern, when forming the black matrix 2 using the KCr thin film, it is necessary to use a stepper etc. with a reticle drawn by EB drawing. It is necessary to use a patterning method with excellent pitch accuracy and dimensional accuracy.

After the black matrix 2 is formed, as shown in FIG.
For example, a red coloring photoresist 3 is applied, and then a photomask 4 corresponding to the first color is placed on the opposite side of the substrate 1 to which the coloring photoresist 3 is applied, keeping a certain gap. Match. Here, the size of the gap is preferably about 30 to 70 μm in order to prevent the photomask 4 and the substrate 1 from coming into contact with each other.

The size of the light transmitting portion of the photomask 4 in the lateral direction in FIG. 1 should be larger than X and smaller than x+a. That is, if the dimensions of the photomask 4 are X+ΔX, Δ
It is sufficient that X satisfies the condition 0<ΔX<a. The same applies to the vertical direction in FIG. In other words, in the present invention, since the black matrix 2 is formed, the photomask 4 is not required to have high precision as conventionally required.

After placing the photomask 4 at a predetermined position, exposure and development are performed to form a colored pattern of the first color as shown in FIG. In addition, during exposure, in order to suppress the influence of scattered light, it is preferable to use substantially parallel light beams with a collimation angle a of about 1 to 3 degrees.

For the second and subsequent colors, by repeating the application of a coloring photoresist corresponding to each color, setting the position of the photomask 4, exposure, and development, a desired coloring pattern as shown in FIG. 1 is formed. Ru.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible. For example, the shape of the colored pattern is
In addition to the dot pattern shown in the figure, a striped pattern may also be used.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an example of a colored pattern, and FIGS. 2, 3, and 4 are diagrams showing steps of a method for forming a color filter according to the present invention. 1...Substrate, 2...Black matrix, 3...
Colored photoresist, 4...Photomask application
People Dai Nippon Printing Co., Ltd.

Claims (3)

[Claims] (1) A method for forming a color filter, in which a coloring photoresist is applied on a transparent substrate, and then exposed through a photomask from the opposite side of the coloring photoresist layer, and then a color filter is formed by repeating the development process. First, a light shielding portion is formed on the transparent substrate other than the portion where the pattern of a predetermined color is arranged, then the coloring photoresist layer is formed, and the coloring photoresist layer is formed on the surface of the transparent substrate opposite to the coloring photoresist layer. A photomask having a light transmitting part corresponding to a pattern of each color is provided on the surface, and by aligning the light shielding part and the light transmitting part of the photomask, the photoresist layer for coloring each color is exposed and developed for each surface. A method for forming a color filter, characterized by performing the following steps. (2) The method for forming a color filter according to claim 1, wherein the light transmitting portion of the photomask is larger than the colored pattern. (3) The method of forming a color filter according to claim 1 or 2, wherein the photomask is arranged with a predetermined gap from the transparent substrate.