JPH09274104A - Production of color filters - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a process for producing color filters capable of entirely eliminating pixel defects after stages of applying, exposing and developing and forming stable images by completely removing the foreign matter sticking to the surfaces of black matrices and color pixel patterns after the formation of these matrices and patterns and simultaneously adequately reforming surface properties. SOLUTION: The production of the color filters is executed in this process by forming the black matrices on a transparent substrate, then applying respective photosensitive resins dispersed with respective pigments of red, green and blue on the black matrix forming surface on this transparent substrate and forming the color pixel patterns by photolithography. In such a case, the black matrices and the color pixel pattern forming surfaces up to the second color are respectively treated by a washing liquid which is adjusted in pH to 9 to 13 by potassium and contains a nonionic surfactant and, thereafter, the photosensitive resins of the ensuing colors are successively applied thereon. The color images are then formed by color lithography.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a color filter, and more particularly to a method for manufacturing a color filter that can eliminate pixel defects and form a stable image.

[0002]

2. Description of the Related Art There are pigment dispersion method, dyeing method, electrodeposition method and printing method as a method of manufacturing a color filter used in a liquid crystal display device, etc., but there are spectral characteristics, durability, pattern shape and accuracy. The pigment dispersion method which is excellent in terms of average is most widely adopted.

The outline of the pigment dispersion method will be described below. First, a black matrix is formed on a glass substrate with a metal light-shielding film such as chromium or chromium oxide, and then, for example, a photosensitive resin in which a red pigment is dispersed is applied on the entire surface by spin coating, and exposed through a mask. . When the image is developed after exposure, red pixels are obtained. The same process as this is green,
If this is also performed for blue pixels, a three-color pixel pattern is formed.

Since the black matrix portion becomes a concave portion between each pixel, an overcoat film of a transparent resin such as an epoxy resin or an acrylic resin is coated for smoothing. In some cases, no overcoat film is provided. Further, a transparent conductive film such as an ITO film is formed on the overcoat film by sputtering or vacuum deposition.

As a method of forming the above black matrix, a method of using a photosensitive resin in which a black material such as carbon black is dispersed has been proposed in addition to the method of using a metal light-shielding film. According to this method, there is an advantage that a large cost reduction can be realized in equipment such as sputtering, electric power, and waste treatment containing chromium.

[0006]

One of the major problems in the color filter manufacturing process is a pixel defect. Pixel defects are roughly classified into three types: white defects, black defects and protrusion defects. Regarding the former two, if there is a visually observable level of defect, it is considered defective.
Usually, it is said that there should not be a single defect having a diameter of 40 to 50 μm or more and a black defect having a diameter of 70 to 100 μm or more on the entire surface. Further, the protrusion defect is the most disliked defect because it causes a common short circuit at the time of bonding with the TFT array, and the height is usually 5 to 10 μm.
There must be no single defect of m or more on the entire surface.

There are various possible causes of pixel defects, but a factor common to all of the above three types of defects is foreign matter adhering to the surface before the photosensitive resin is applied. If the adhered foreign matter and the photosensitive resin have a high affinity, the foreign matter is taken into the photosensitive resin, and the size, height, and
It becomes a black defect or a protrusion defect depending on the light transmittance. Also,
When the affinity between the adhering foreign matter and the photosensitive resin is poor, the repelling of both causes white defects. The size of the foreign matter and the size of various defects do not uniquely correspond to each other, and vary greatly depending on the type of foreign matter.

In addition to the above-mentioned foreign matters, it has been known that the white defects are increased even when the surface roughness of the surface to be coated, surface functional groups, adsorbed water and the like are not suitable. Therefore, it is considered that if the physical properties of the surface to be coated are appropriately modified, the adhesion between the surface to be coated and the photosensitive resin is improved and white defects are reduced.

In order to solve the above problems, in the method of manufacturing a color filter, the surface after the black matrix and color pixel pattern formation is usually washed to remove the adhering foreign matter and to modify the surface to be coated. After that, the photosensitive resin is applied, but with the conventionally proposed cleaning method, the adhered foreign matter cannot be sufficiently removed.
Modification of the coated surface is not sufficient.

Recently, for example, NaOH or KOH 25
% By weight, a chelating agent comprising at least one kind of anionic surfactant, hydroxycarboxylic acid, aminocarboxylic acid or a salt thereof or a water-soluble polymer, alkyl ether sulfate ester salt, alcohol, polyhydric alcohol, At least 2 in glycol ether solvent
A method of cleaning a glass substrate using a strong alkaline liquid cleaning composition containing at least one kind of stabilizer has been proposed (JP-A-6-108092).

However, the above-mentioned cleaning method exhibits an excellent effect for cleaning oils and fats attached to the glass substrate, but is sufficiently effective for removing foreign matters attached to the black matrix and the color pixel pattern forming surface. In addition, since the cleaning solution is too alkaline, the already formed pattern is damaged, and many defects remain as a result.

A color by a transfer method characterized by including a step of rubbing the surface of a substrate having a patterned photosensitive resin layer with a brush in a residual developing film removing liquid containing a surfactant as a main component. A method for manufacturing a filter has been proposed (JP-A-6-258514). According to this manufacturing method, it is said that an excellent color filter having no development residual film and no peeling of pixels can be obtained.

However, when the above method is directly applied to the method for producing a color filter by the pigment dispersion method, there are the following problems. That is, when using a cleaning solution without addition of an alkali as a builder, a large number of defects remain because the effect of removing adhering foreign matter on the surface before application of the photosensitive resin is small, and when using a cleaning solution with an alkali added, The use of the sodium-based alkali described in Japanese Patent Laid-Open Publication No. 2001-242242 reduces the number of defects, but makes the image formation unstable and lowers the yield.

The present invention has been made in view of the above circumstances, and an object thereof is to completely remove foreign matter adhering to the surface after forming a black matrix and a color pixel pattern and at the same time appropriately modify the physical properties of the surface. Accordingly, it is an object of the present invention to provide a method for producing a color filter which can eliminate a pixel defect after the steps of coating, exposing and developing and form a stable image.

[0015]

As a result of various studies, the inventor of the present invention can easily achieve the above object if the surface after the black matrix and color pixel pattern formation is treated with a specific cleaning liquid. I got the knowledge.

The present invention has been completed based on the above findings, and the gist thereof is that after forming a black matrix on a transparent substrate, red, green, and In a method for producing a color filter in which each photosensitive resin in which each blue pigment is dispersed is applied and a color pixel pattern is formed by photolithography, the pH is adjusted to 9 to 13 with potassium and a nonionic surfactant is used. A black matrix and a surface for forming a color pixel pattern up to the second color are treated with a cleaning liquid containing, respectively, and then a photosensitive resin of the next color is sequentially applied to form a color pixel by photolithography. There is a method of manufacturing a color filter for

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.
The color filter in the invention is manufactured by a known pigment dispersion method. That is, after forming a black matrix on a transparent substrate, each photosensitive resin in which red, green, and blue pigments are dispersed is applied to the black matrix forming surface of the transparent substrate, and color pixels are formed by photolithography. Form a pattern.

As the transparent substrate, glass is usually used, and preferably alkali-free glass is used. The black matrix may be composed of a metal light-shielding film such as chromium or chromium oxide, but is preferably composed of a photosensitive resin in which carbon black is dispersed. The photosensitive resin composition required for forming the black matrix and the pixel pattern of each color is usually a binder component such as an acrylic resin or a polyimide resin, a color material, a color material powder, or photopolymerization that initiates a polymerization reaction by light irradiation. It is prepared by mixing an initiator, a diluent solvent and the like.

The feature of the present invention is that the pH value is 9 with potassium.
Each of the black matrix and the color pixel pattern forming surface up to the second color is treated with a cleaning liquid adjusted to 13 and containing a nonionic surfactant, and then a photosensitive resin of the next color is sequentially applied. Color pixels are formed by photolithography. As described above, the black matrix is preferably a resin black matrix.

In the present invention, the kind of the nonionic surfactant used in the cleaning liquid is not particularly limited, but the structure represented by the following general formula (where R = C _m H _{2m + 1} (6 ≦ m ≤
Those having 11) are preferred. And you may use together with the nonionic surfactant of another structure.

[0021]

Embedded image R-φ- (OCH ₂ CH ₂ ) _n OH (where R: C _m H _{2m + 1} (6 ≦ m ≦ 11), φ: phenylene group, 5 ≦ n ≦ 20)

In the present invention, the concentration of the nonionic surfactant in the cleaning liquid is usually selected in the range of 0.01 to 10% by weight, preferably 0.1 to 5% by weight. Further, the potassium in the cleaning liquid is preferably potassium hydroxide or potassium carbonate. Then, in the cleaning liquid, EDTA
A chelating agent such as or the like, a carboxylic acid having a complexing action, or the like may be contained.

In the present invention, the cleaning liquid used is a cleaning liquid from which foreign matters are removed from the viewpoint of performing precision cleaning, but the particle concentration of 0.2 μm or more is preferably 10 particles / ml or less, more preferably. Use a washing solution of 5 pieces / ml or less. The cleaning liquid is usually used at a temperature of normal temperature or higher, but is preferably used after being heated to a temperature of 30 ° C. or higher.

In the present invention, the cleaning treatment is preferably carried out in combination with a mechanical cleaning method. More preferably, it is performed in combination with at least one of ultrasonic cleaning and brush cleaning. The washing time is set to an appropriate time, but is usually 20 seconds or longer, preferably 30 seconds or longer. Further, in the present invention, it is preferable that the above-mentioned cleaning treatment is carried out while introducing the transparent substrates one by one into the cleaning area by the transfer means and sequentially transferring them.

In the present invention, the reason why the adhering foreign matter on the surface after the formation of the black matrix or the color pixel pattern is completely removed and the surface is appropriately modified is not yet clear, but it is not clear that the alkaline action by potassium is It is considered that this is due to the combined effect with the ionic surfactant.

[0026]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to the following examples unless it exceeds the gist.

Examples 1 to 3 and Comparative Examples 1 to 5 A coating solution of a photosensitive resin composition in which carbon black was dispersed in an acrylic resin as a main component was applied to a glass substrate (Asahi Glass "AN-635"; length: Horizontal: Thickness = 370 x 470 x
0.7mm) surface with spin coater 1.0μm
Was applied to form a resin black matrix after exposure and development, followed by a curing treatment by hot air drying at a temperature of 200 ° C. for 10 minutes. Next, the glass substrate with the resin black matrix was placed in a circulating overflow tank containing the cleaning liquid shown in Table 1
After soaking for a minute, a pure water rinse treatment and an air knife drying were performed. The temperature of the cleaning liquid was set to 40 ° C., and ultrasonic cleaning at 50 kHz was used for the cleaning.

Next, a photosensitive resin in which a red pigment is dispersed in an acrylic resin as a main component is applied on the surface of the resin black matrix by a spin coater to a uniform thickness of 1.5 μm, and then exposed and developed to give red pixels. Got the pattern. Hereinafter, a photosensitive resin in which a green pigment was dispersed and a photosensitive resin in which a blue pigment was dispersed were sequentially used, and green and blue pixel patterns were obtained by the same operation as above. At this time, the red pixel pattern forming surface and the green pixel pattern forming surface were washed under the same conditions as above. Then, during the formation of each color pixel pattern, as a typical example, 1000 μ on the red pixel pattern is formed.
Number of white defects and peelings having an area of m ² or more, 1
The number of black defects having an area of 0000 μm ² or more and the number of protrusions having a height of 10 μm or more were measured, and the results are shown in Table 1.

Comparative Example 4 In Example 1, as the cleaning liquid, JP-A-6-1080 was used.
92, ie 1.2% by weight of C ₁₄
α-olefin sulfonic acid sodium, 2% by weight of ethylenediaminetetraacetic acid 4 soda, 2% by weight of ethanol,
9% by weight of propylene glycol, 4% by weight of 3-methyl-3-methoxybutanol, 0.8% by weight of polyoxyethylene butyl ether sulfate ester soda K
A red pixel pattern was formed on the surface of the resin black matrix in the same manner as in Example 1 except that a cleaning liquid adjusted to pH 14 or higher with OH was used. The defects on the obtained red pixel pattern were measured, and the results are shown in Table 2.

Comparative Example 5 In Example 1, as the cleaning liquid, JP-A-6-1080 was used.
No. 92, namely, 15% by weight of sodium dodecylbenzenesulfonate (“Neogen” manufactured by Dai-ichi Kogyo Co., Ltd.) and 11% by weight of polyoxyethylene nonylphenyl ether (“Nonion” manufactured by NOF Corporation). NS
208.5 "), 30% by weight of sodium pyrosulfate, and the balance being water, using a nylon roll brush with a fiber diameter of 50 μm and hair legs of 25 mm while showering the above cleaning liquid on the surface of the resin black matrix. Except that it was used and contact-cleaned at 100 rom for 5 seconds,
In the same manner as in Example 1, red pixel patterns were formed on the surface of the resin black matrix. The defects on the obtained red pixel pattern were measured, and the results are shown in Table 2.

Comparative Example 6 A red pixel pattern was formed on the surface of the resin black matrix in the same manner as in Example 1 except that the washing treatment was omitted. The defects on the obtained red pixel pattern were measured, and the results are shown in Table 2.

[0032]

[Table 1]

[0033]

[Table 2]

[0034]

According to the present invention described above, since it is possible to completely remove the foreign matter attached to the black matrix and the color pixel pattern forming surface on the transparent substrate and to appropriately modify the surface, It is possible to eliminate pixel defects after the steps of coating, exposing, and developing the color photosensitive resin, and to form a stable image. As a result, according to the present invention, the production yield of color filters is significantly improved, and the industrial value of the present invention is great.

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[Procedure amendment]

[Submission date] September 19, 1996

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claim 5

[Correction method] Change

[Correction contents]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0023

[Correction method] Change

[Correction contents]

In the present invention, the cleaning liquid used is a cleaning liquid from which foreign matters are removed from the viewpoint of performing precision cleaning, but the number of particles having a particle size of 0.2 μm or more is preferably 10 particles / ml. Hereinafter, more preferably, 5 or less washing solutions are used. The cleaning liquid is usually used at a temperature of normal temperature or higher, but is preferably used after being heated to a temperature of 30 ° C. or higher.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0030

[Correction method] Change

[Correction contents]

Comparative Example 5 In Example 1, as the cleaning liquid, JP-A-6-1080 was used.
No. 92, namely, 15% by weight of sodium dodecylbenzenesulfonate (“Neogen” manufactured by Dai-ichi Kogyo Co., Ltd.) and 11% by weight of polyoxyethylene nonylphenyl ether (“Nonion” manufactured by NOF Corporation). NS
208.5 "), 30% by weight of sodium pyrosulfate, and the balance being water, using a nylon roll brush with a fiber diameter of 50 μm and hair legs of 25 mm while showering the above cleaning liquid on the surface of the resin black matrix. Except that it was used and contact-cleaned at 100 rpm for 5 seconds,
In the same manner as in Example 1, red pixel patterns were formed on the surface of the resin black matrix. The defects on the obtained red pixel pattern were measured, and the results are shown in Table 2.

Claims (9)

[Claims] 1. A black matrix is formed on a transparent substrate, and then each photosensitive resin in which red, green and blue pigments are dispersed is applied to the black matrix forming surface of the transparent substrate, and photolithography is performed. In the method of manufacturing a color filter for forming a color pixel pattern according to the above, the black matrix and the second surface of the color pixel pattern forming surface up to the second color are washed with a cleaning solution having a pH adjusted to 9 to 13 with potassium and containing a nonionic surfactant. A method for producing a color filter, which comprises subjecting each to a treatment, then sequentially applying a photosensitive resin of the next color, and forming color pixels by photolithography. 2. The production method according to claim 1, wherein the nonionic surfactant has a structure represented by the following general formula. Embedded image R-φ- (OCH ₂ CH ₂ ) _n OH (where R: C _m H _{2m + 1} (6 ≦ m ≦ 11), φ: phenylene group, 5 ≦ n ≦ 20) 3. The production method according to claim 1, wherein the concentration of the nonionic surfactant in the cleaning liquid is 0.01 to 10% by weight. 4. The production method according to claim 1, wherein the potassium in the cleaning liquid is potassium hydroxide or potassium carbonate. 5. A cleaning liquid having a concentration of particles of 0.2 μm or more of 10 particles / ml or less is used.
The manufacturing method according to any one of 1. 6. The manufacturing method according to claim 1, wherein the temperature of the cleaning liquid is 30 ° C. or higher. 7. The manufacturing method according to claim 1, wherein the cleaning treatment is performed by using at least one of ultrasonic waves and a brush. 8. A cleaning treatment for 20 seconds or more.
The manufacturing method according to any one of 1. 9. The manufacturing method according to claim 1, wherein the transparent substrate is introduced into the cleaning area one by one by the transfer means and the cleaning process is performed while sequentially transferring the transparent substrates.