JP2005128562A - Method for manufacturing color filter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that when superimposing a pixel and either a black matrix or pixels, the superimposed convex-concave parts tend to cause cracks in ITO on the superimposed convex-concave part, leading to lowering of reliability. <P>SOLUTION: In a method for manufacturing a color filter composed of the pixel and either the black matrix or the pixels, the film thickness of these component members are almost the same. And the bulge of the superimposed convex part of the pixel and either the black matrix or the pixels is 0.4μm or less toward each coloring pixel. Furthermore, the dimension of the superimposed part of the pixel and either the black matrix or the pixels is 1.0 to 9.0 μm. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing a color filter used in combination with a display device such as a liquid crystal display device and a line sensor, or a light receiving device.

  Color filters using a black matrix as a light shield are roughly divided into two types.

  A) Etching a metal thin film such as Cr, using this as a black matrix, forming colored pixels on it, and forming a color filter. FIG. 2A shows a cross-sectional view of a color filter in which pixels are formed by etching a metal thin film. A metal thin film is vapor-deposited on a transparent glass substrate, and necessary portions are removed by etching to make it light transmissive, and colored pixels of red, blue, and green are formed thereon. Finally, a transparent conductive film, for example, ITO is formed thereon to obtain a color filter. The black matrix obtained by etching this metal thin film has become the mainstream at present because the optical density of the light-shielding portion can be 3 or more and it can be formed finely.

  B) Making a black pigment-dispersed photosensitive resin, using it as a black matrix, forming colored pixels on it, and forming a color filter. FIG. 2B is a cross-sectional view of a color filter in which a black pigment-dispersed photosensitive resin is made and pixels are formed thereon. A black matrix is formed on a transparent glass substrate through a series of photolithography processes such as application, exposure, and development of black pigment-dispersed photosensitive resin, and red, blue, and green colored pixels are formed in each opening. To do. Finally, a transparent conductive film, for example, ITO is formed thereon to obtain a color filter. The black matrix using the black pigment-dispersed photosensitive resin is disadvantageous in that the optical density of the light-shielding part is small and fine processing is difficult as compared with the type using the metal thin film. However, it does not require a metal vacuum deposition process, which contributes to a reduction in manufacturing costs. For this reason, development of a black pigment-dispersed photosensitive resin has been advanced, and it is becoming possible to form a black matrix that can be used practically.

  On the other hand, in the conventional color filter, a resin film called a transparent protective film is formed between the colored pixels and the ITO. This is because the chemical resistance of the colored pixels is improved, the surface unevenness is relaxed, and the surface stress during the formation of the transparent conductive film is minimized. However, an extra step of forming the transparent protective film is necessary, and the raw material and the manufacturing cost are increased correspondingly. Therefore, the process of adopting the transparent protective film is decreasing at present.

  By the way, when forming a black pixel after forming a black matrix with a black pigment-dispersed photosensitive resin, the overlapping portion of the black matrix and the colored pixel is about 3 μm in total due to the film thickness of both, There was a problem of becoming. In order to obtain sufficient color characteristics for the colored pixels and a sufficient optical density for the black pigment-dispersed photosensitive resin, a film thickness of about 1.5 μm is required.

  As a result, when a transparent conductive film is deposited or when heat treatment is performed in a subsequent process, for example, a liquid crystal cell manufacturing process, a black black matrix or colored pixels having a large thermal expansion expands, and a transparent inorganic substance having a relatively small thermal expansion. Interfacial stress occurs between the conductive film, causing delamination between the black black matrix or colored pixels and the transparent conductive film, reducing the reliability of the color filter, or cracking the transparent conductive film There arises a problem that causes an increase in surface resistance. This phenomenon is more susceptible to the thicker the organic material located in the lower layer. In addition, this phenomenon was also observed when colored pixels were superimposed.

  Furthermore, when the transparent conductive film is formed directly on the colored pixels and the black matrix without using the transparent protective film, the above phenomenon is more likely to occur because there is no effect of reducing the surface unevenness due to the transparent protective film. .

  In view of the above problems, the present invention has been completed as a result of examination. The gist of the present invention is that, in the method of manufacturing a color filter in which colored pixels are regularly arranged on a substrate, at least The colored pixels are made of a pigment-dispersed photosensitive resin, and by controlling the pre-baking temperature of the pigment-dispersed photosensitive resin, the end portions of the patterns of the colored pixels are overlapped, and the overlapping dimension is 1 0.0 μm to 9.0 μm, and the rise of the portion where the end portions of the colored pixels overlap each other is 0.4 μm or less with respect to the thickness of each colored pixel. The color filter manufacturing method is characterized in that the film thickness is substantially the same. According to a second aspect of the present invention, in the method for producing a color filter in which colored pixels are regularly arranged on a substrate and at the same time, a black matrix, at least the colored pixels or the black matrix are composed of a pigment-dispersed photosensitive resin, and the pigment dispersion By controlling the pre-baking temperature of the type photosensitive resin, the colored pixel pattern and the end of the black matrix pattern are overlapped, and the overlapping dimension is 1.0 μm to 9.0 μm. And the rise of the portion where the end of the black matrix overlaps is 0.4 μm or less with respect to the thickness of each colored pixel, and the thickness of each colored pixel excluding the raised portion and the thickness of the black matrix are A color filter manufacturing method characterized by being substantially identical.

  In other words, in the first and second inventions, it has been found that cracks in the transparent conductive film or delamination between the colored pixels and the black matrix can be prevented by making the thickness of the colored pixels and the thickness of the black matrix substantially the same. Depending on the results. That is, as described above, when substances having different thermal expansions are in contact with each other in two layers, stress acts on the interface. This tendency increases as the organic layers constituting the colored pixels and the black matrix become thicker. For this reason, it is desirable that the film thickness be as small as possible.

  On the other hand, there is a limit to the thin film thickness of the organic layer. This is because excessive addition of pigment to the pigment-dispersed photosensitive resin of each color for forming the organic layer leads to a reduction in sensitivity, and is therefore limited. For this reason, the film thicknesses of the colored pixels and the black matrix are both 1.0 to 1.5 μm. From the above, while it is necessary to make the pixel thickness of the colored pixels and the black black matrix as thin as possible, it is necessary to avoid the occurrence of overlapping portions of pixels and prevent cracks and delamination between the organic layer and ITO. is there.

  Furthermore, cracks are likely to occur at sites where the film thickness changes rapidly. This is because stress is applied due to expansion / contraction of each layer during heating or cooling, and the stress is concentrated on the part.

  On the other hand, it is technically impossible for each colored pixel and the black matrix to be adjacent to each other without any gap, and there is no overlapping portion between the colored pixels or the colored pixel and the black matrix. It must be allowed.

  According to the inventor's experiment, it has been found that if the overlapped portion is raised to 0.4 μm or less with respect to the film thickness of each pixel, problems such as cracks do not occur.

  FIG. 3 shows the relationship between the pre-baking temperature and the dimensional change amount (design size is 0 μm and the image shift amount is shown) using a black pigment-dispersed photosensitive resin. When the pre-baking temperature is 40 ° C., the dimensional change is 0.5 μm, but when it reaches 120 ° C., it becomes 3.0 μm. The reason why the pre-baking temperature and the dimensional change are dependent on the pre-baking is considered to be because the pre-baking causes a slight cross-linking and facilitates radical polymerization. It can also be seen that the higher the temperature, the easier the taper. Since this taper is formed, light leakage of the color filter can be prevented while flattening the surface of the color filter even if the end of the colored pixel and the end of the black matrix are overlapped. Therefore, the color filter of the present invention can be obtained by a simple process device by controlling the design size of the photomask and the prebake temperature.

  FIG. 4 shows the relationship between the pre-baking temperature and the dimensional change of the pigment-dispersed photosensitive resin for each color. Although there is a slight difference depending on the color, the dimensional change amount (taper width) increases as the pre-baking temperature increases as in the black pigment-dispersible photosensitive resin in FIG.

  According to the present invention, even if ITO is deposited directly on the colored pixels and the black matrix, the possibility of causing cracks in the ITO and delamination at the interface between the ITO and the colored pixels in the subsequent steps is significantly reduced. The reliability of the color filter without the surface protective film is improved. Furthermore, even a color filter having a surface protective film has an effect that the surface flatness is further improved and the reliability of the color filter is improved.

(Formation of Pigment Photosensitive Resin) First, a photosensitive resin serving as a base material for a pigment-dispersed photosensitive resin was mixed with the following composition.
O-cresol novolac epoxy acrylate (50% of the hydroxyl groups reacted with phthalic anhydride) 9.5 parts by weight Dipentaerythritol hexaacrylate 9.5 parts by weight Irgacure 1.0 parts by weight Ethyl sesosolve: 80.0 parts by weight This photosensitive resin, pigment and solvent were mixed in the following mixing ratio.
Black pigment-dispersed photosensitive resin-Carbon black ... 10 parts by weight-Photosensitive resin ... 5 parts by weight-Ethyl cellosolve ... 85 parts by weight Red pigment-dispersed photosensitive resin-Pyrazolone red ... 10 parts by weight-Photosensitive resin ... 5 parts by weight- Ethyl cellosolve ... 85 parts by weight Green pigment dispersed photosensitive resin-Lionol green 2Y-301 ... 9 parts by weight-Photosensitive resin ... 5 parts by weight-Ethyl cellosolve ... 86 parts by weight Blue pigment dispersed photosensitive resin-Fast Gen Blue ... 3 Part by weight-photosensitive resin ... 5 parts by weight-Ethyl cellosolve ... 92 parts by weight or more pigment photosensitive resin of each composition is kneaded with three rolls, this is rotated for 5 minutes with a centrifuge at 10,000 rpm, and the supernatant Only, and then filtered through a 1.0 μm membrane filter to remove large particles. .

(Formation of black matrix) A black pigment-dispersed photosensitive resin was applied to a glass substrate so as to have a film thickness of 1.5 μm, and prebaked by heating on a hot plate at 90 ° C. for 5 minutes. The black pigment-dispersed photosensitive resin formed by coating was exposed with an ultrahigh-pressure mercury lamp through a photomask (exposure amount 200 mJ / cm ² ), and developed with a 0.1% aqueous sodium carbonate solution for 1 minute. The obtained relief pattern of the black pigment-dispersed photosensitive resin was heated in an oven at 200 ° C. for 30 minutes.

  (Formation of each colored pixel) A red pigment-dispersed photosensitive resin was applied on the black matrix created above so as to have a thickness of 1.5 μm, and heated on a hot plate at 90 ° C. for 5 minutes. Pre-baked. Further, exposure, development and post-baking were performed in the same manner as described above. These steps were repeated in the order of green and blue to form a color filter in which primary color pixels were regularly arranged and a black matrix was arranged around these pixels.

1 is a cross-sectional structure diagram of a color filter showing an example of the best mode of the present invention. It is sectional drawing of the conventional color filter. It is a figure which shows the prebaking temperature and dimensional change amount in a black pigment dispersion photosensitive resin. It is a figure which shows the prebaking temperature and dimensional change amount of each color pigment dispersion photosensitive resin.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11, 11 '... Board | substrate 12, 12' ... Colored pixel 13 ... Light shielding layer 21, 21 '... Board | substrate 23 ... Metal light shielding film 24, 24' ... Colored pixel 25 ... Black pigment using black pigment dispersion photosensitive resin Light-shielding layer by resin using dispersed photosensitive resin

Claims (2)

  In a color filter manufacturing method in which colored pixels are regularly arranged on a substrate, at least the colored pixels are composed of a pigment-dispersed photosensitive resin, and the pre-baking temperature of the pigment-dispersed photosensitive resin is controlled, The end portions of the pattern of the colored pixels are overlapped, the overlapping dimension is 1.0 μm to 9.0 μm, and the bulge of the portion where the end portions of the colored pixels are overlapped with respect to the film thickness of each colored pixel The method for producing a color filter is characterized in that the thickness is 0.4 μm or less, and the thickness of each colored pixel excluding the raised portion is substantially the same. In a method for producing a color filter in which colored pixels are regularly arranged on a substrate and simultaneously formed of a black matrix, at least the colored pixels or the black matrix are composed of a pigment-dispersed photosensitive resin, and the pre-baking of the pigment-dispersed photosensitive resin is performed. By controlling the temperature, the colored pixel pattern and the end of the black matrix pattern are overlapped, and the overlapping dimension is 1.0 μm to 9.0 μm, and the end of the colored pixel and the black matrix is overlapped. The rise of the overlapping portion is 0.4 μm or less with respect to the thickness of each colored pixel, and the thickness of each colored pixel excluding the raised portion is substantially the same as the thickness of the black matrix. A characteristic color filter manufacturing method.

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