JPH09230124A - Color filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To relieve positional accuracy and to make it possible to form color filters having fine patterns by patterning the peripheral parts of adjacent filter layers so as to overlap these parts on each other with light shielding layers and flattening the build-ups of the overlap parts by polishing. SOLUTION: Black matrices 2 which are the light shielding layers are pattern formed on a substrate 1 and, thereafter, the filter layer 3R of the first color is pattern formed. Next, the filter layer 3G is patterned in such a manner that the pixel ends thereof overlap on the pixel ends of the filter layer 3R. Similarly, the filter layer 3B is patterned as well. The overlap parts 3A are thereafter removed by the polishing treatment to flatten the surface of the filter layers 3. Consequently, the difference in level of the intra-surface film thickness is confined within 0.5μm. Transparent electrodes (ITO) are sputtered directly on the color filters after the stages described above. In such a case, the film deposition condition of the transparent electrodes is good.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color filter used in a color liquid crystal display device, a plasma display panel or the like, and more particularly to a color filter having a high definition pattern.

[0002]

2. Description of the Related Art In order to perform color display in a color liquid crystal display device, red, green and blue filter layers are patterned on a light-shielding layer (black matrix) having a pattern having openings in a light transmitting portion. Color filters are commonly used. The recent market demand for liquid crystal display devices is to improve the aperture ratio of the color filter to improve the screen brightness, and to increase the definition of pixels to increase the added value of products using the liquid crystal display device. Is required to do. However, at the stage of realizing those requirements, the accuracy of alignment of pixel patterns in the process of manufacturing a color filter becomes a serious problem.

According to the prior art, as shown in FIG. 1, when the line width a of the patterned light-shielding layer 2 (black matrix) is small, the pixel position shift is half the light-shielding portion line width a (a /
2) or less, and it was difficult to manufacture a product having a light-shielding part line width a of less than 8 μm due to the positional accuracy of the manufacturing apparatus.

In the example of FIG. 1 described above, the filter layer 3 has a striped elongated continuous pattern, but the filter layer 3 has a delta arrangement as shown in FIG. 4 (a) or 4 (b). In this case, in addition to the above problems, there were the following problems. That is, as shown in FIG. 5, the dot pixels 3d in the delta array of (b) have a long island-shaped pixel per unit area, compared to the stripe filter pixel layer 3s of (a). , The speed of development and etching during pattern formation is faster, and the cross section is shown in FIG. 6 (a).
It is highly possible that the taper will have an inverse taper shape, as shown in FIG.
As shown in (b), when the transparent electrode 4 (ITO) film was applied, there was a high risk of causing disconnection failure.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above problems in manufacturing a color filter having a pixel pattern having a light-shielding portion having a narrow line width.

[0006]

According to the present invention, a patterned light-shielding layer formed on a transparent substrate and a plurality of color filter layers are sequentially formed in an opening where the light-shielding layer is not formed. In the color filter, the peripheral portions of the adjacent filter layers are patterned so as to overlap each other on the light-shielding layer, and the ridge of the overlapping portion is flattened by polishing. The invention is applied to a color filter in which the line width of the light shielding layer obtained by the above manufacturing process is 8 μm or less,
Preferably, the present invention is a color filter in which the in-plane film thickness difference obtained by the above manufacturing process is within 0.5 μm.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. First, as shown in FIGS. 2 and 7, the black matrix 2 as a light shielding layer is patterned on the substrate 1 by photolithography or the like, and then the first color filter layer 3R is patterned. Next, the filter layer 3G is patterned so that the pixel ends thereof overlap the pixel ends of the filter layer 3R. Similarly, the filter layer 3B is also patterned.

This process will be described by taking a case of a delta arrangement pattern as an example. As shown in FIG. 9, when the pixel pitch is X direction x, Y direction y, and Cr line width (narrowest portion) is a, the pixel is The overlapping dimension b of is determined in consideration of the condition that the filter layer of the adjacent pixel does not enter the effective pixel portion (the opening portion of the black matrix pattern), that is, the color mixture or the pattern non-adhesion in the effective pixel portion, that is, the white spot does not occur. Also 0
It can be designed to be not less than μm and not more than aμm. Letting this be X direction: b ₁ μm and Y direction: b ₂ μm, 1
The design dimensions of the pixel are (x + 2b ₁ ) μm in the X direction and (y + 2b ₂ ) μm in the Y direction. The misalignment tolerances during pattern exposure, as can be seen from FIG. 10, for X-direction smaller ones of b ₁ or a-b _1, for Y direction b ₂ or a-b ₂ It becomes a small value of them. As a result, the narrowest C that can be formed
The r line width can be up to about 4 μm.

After that, the overlapping portion 3A is polished and removed by polishing treatment as shown in FIGS. 3 and 8, and the surface of the filter layer 3 is flattened. As a result, the in-plane film thickness step is reduced to 0.
It can be within 5 μm. After the above steps, the transparent electrode (IT
O) may be sputtered, but in that case, the film deposition condition of the transparent electrode is good, and the end shape of the patterned resist cross section, which has occurred conventionally, becomes an inverse taper shape. No clear disconnection of the transparent electrode is seen in any part.

[0010]

According to the method of the present invention, the required positional accuracy is substantially alleviated, and even a color filter having a fine pattern with a light-shielding portion line width of 8 μm or less can be easily produced. Further, in the color filter of the delta arrangement, a flat color filter having an extremely small in-plane film thickness difference can be obtained without increasing processes such as overcoating. Therefore, there is no fear of the disconnection defect that has occurred when the ITO film is attached to the color filter manufactured by the conventional method. Further, in the STN type liquid crystal display device, the allowable range of the surface step difference is as small as 0.5 μm or less, but in the present invention, tilt reverse (liquid crystal alignment defect) or the like that tends to occur when the surface step difference is large does not occur. This has the effect of improving the display quality.

[0011]

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example of a conventional color filter.

FIG. 2 is an explanatory view showing the process of manufacturing the color filter of the present invention.

FIG. 3 is an explanatory diagram showing an embodiment of a color filter of the present invention.

4A and 4B are explanatory diagrams showing an example of pixels in a delta array.

5 (a) and 5 (b) are explanatory views schematically showing the situation of side etching.

6A and 6B are explanatory diagrams showing a state of a color filter having a pattern section of an inverse taper shape.

FIG. 7 is an explanatory view showing the manufacturing process of the color filter of the present invention.

FIG. 8 is an explanatory diagram showing an embodiment of the color filter of the present invention.

FIG. 9 is an explanatory diagram showing design dimensions of a color filter.

FIG. 10 is an explanatory diagram showing design dimensions of a color filter.

[Explanation of symbols]

 1 transparent substrate 2 light shielding layer 3 filter layer 4 transparent electrode

Claims (3)

[Claims] 1. A color filter comprising a pattern-shaped light-shielding layer formed on a transparent substrate and filter layers of a plurality of colors sequentially formed in an opening where the light-shielding layer is not formed. The color filter is characterized in that the peripheral portions thereof are patterned so as to overlap each other on the light-shielding layer, and the protrusions of the overlapping portions are flattened by polishing. 2. The line width of the light shielding layer is 8 μm or less.
Color filter as described. 3. The color filter according to claim 1, wherein the in-plane film thickness difference is within 0.5 μm.