JPH09281318A - Production of color filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress and control the residue of a photosensitive resin remaining after development and to improve the production yield of a color filter. SOLUTION: In this production method, a black matrix is formed on a transparent supporting body, and then color pixels are formed by photolithography using a photosensitive resin in which red, green and blue pigments are dispersed on the supporting body. Before the photosensitive resin is applied, the surface to be coated is treated with ozone to control the contact angle with water to between >=12 deg. and <=40 deg. in the area where no pixel is formed. The ozone treatment is carried out in an atmosphere of >=1ppm ozone concn, at >=30 deg.C and for >=30sec. Further, the treatment is carried out in such an environment containing <=1000 particles per 1 cubic foot of particles having >=0.5μm particle size.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device and a method of manufacturing a color filter for an electro-optical display device of precision electronic equipment.

[0002]

2. Description of the Related Art There are pigment dispersion method, dyeing method, electrodeposition method, printing method and the like 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 most widely used method is a pigment dispersion method, which has excellent properties on average in terms of points.

The outline of the pigment dispersion method will be described below. Usually, a black matrix is first formed on a transparent support such as a glass substrate by 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 spin-coated on the entire surface, Exposing through a mask. When the image is developed after exposure, red pixels are obtained. When the same process is performed for green and blue pixels, three color pixels are formed. Since the black matrix portion becomes a recess between each pixel, it is covered with an overcoat film of a transparent resin such as an epoxy resin or an acrylic resin for smoothing. The overcoat film may not be provided in some cases. 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 black matrix, a method of using a photosensitive resin in which a black pigment such as carbon black is dispersed has been proposed in addition to the method of using the metal light shielding film. According to this method, it is possible to realize a significant cost reduction such as equipment such as sputtering, reduction of electric power, and treatment of waste liquid containing chromium, and there are great advantages in environmental protection.

[0005]

Problems in the manufacturing process of the color filter include defects and residues of the photosensitive resin film. Among the white defects, which is one type of defects, the chipping and peeling of pixels are usually improved by increasing the adhesion between the photosensitive resin and the transparent support. On the other hand, the residue of the photosensitive resin film is generally improved by lowering the adhesion between the photosensitive resin and the transparent support. That is, there is a so-called trade-off (alternate choice) between the chipping and peeling of the pixel and the residue of the photosensitive resin film.

The adhesion between the photosensitive resin and the transparent support is usually optimized by improving the composition of the resin and the like, and is controlled under the condition that both chipping and peeling of pixels and resin film residue are optimized. . However, particularly when the next pixel is formed after the pixels of one or more colors are formed, the resin film residue of the previous color has a strong adhesive action between the next pixel and the support, and therefore The adhesion between the photosensitive resin and the transparent support becomes very high, the resin film residue of the next color increases greatly, and it becomes difficult to control the resin composition only by improving the composition. In addition, when a photosensitive resin is used for the black matrix, the process of coating, exposure, and development is increased by one step, so that the residue is further amplified, and finally there is a resin film residue that can be clearly confirmed visually. The problem of remaining remains.

[0007] When such a residue remains, there arises a problem that the adhesiveness at the time of attachment to the TFT array is deteriorated and the sealing is deteriorated. In addition, since pixels of other colors are superimposed on the residue, the color tone of the pixels may change.
In the method of manufacturing a color filter, the surface to be coated is irradiated with UV light before being coated with the photosensitive resin to modify the surface,
A method for coating is proposed in JP-A-2-294602. However, since this method focuses on removing organic contaminants on the substrate, the UV irradiation time is long, the adhesiveness of the photosensitive resin is reduced, and white defects such as chipping and peeling are reversed. It increased, which was not preferable.

Further, there is a method of cleaning the color filter by UV irradiation to modify the surface thereof, as disclosed in JP-A-63-16203.
8, JP-A-5-134397 and JP-A-5-22416
Proposed in 7. According to these methods, the “wettability” after UV irradiation treatment is improved, so the cleaning effect of contaminants such as fine particles and organic substances is improved, but conversely, regarding the adhesion of the photosensitive resin in the subsequent step, Since it decreases as described above, white defects such as chipping and peeling tend to increase.

In view of the above problems, an object of the present invention is to control the adhesive action of the resin film residue of the previous color and optimize the adhesion between the next color and the support, thereby To provide a method for manufacturing a color filter that enables control of chipping, peeling, and resin film residue, and can control pixel chipping, separation, and resin film residue after forming all colors to the most preferable state. is there.

[0010]

As a result of various studies to solve the above-mentioned problems, the inventors of the present invention bring a specific state to the surface to be coated before coating the photosensitive resin. By carrying out such ozone treatment, it was found that the adhesion between the photosensitive resin and the surface to be coated is lowered, and consequently the amount of resin film residue can be controlled, and the present invention was reached.

That is, the gist of the present invention is that after a black matrix is formed on a transparent support, a red matrix is formed on the support.
In a method for producing a color filter by forming color pixels by photolithography using a photosensitive resin in which green and blue pigments are dispersed, in a method for producing a color filter, the surface to be coated is treated with ozone before coating the photosensitive resin, A method for producing a color filter is characterized in that a contact angle of water with respect to a portion without pixels is set to a lower limit of 12 ° or more, preferably 15 ° or more, and an upper limit of 40 ° or less, preferably 30 ° or less.

Hereinafter, the present invention will be described in detail. The color filter in the present invention is manufactured by a pigment dispersion method, and the photosensitive resin used is usually an acrylic resin or a polyimide resin as a binder component, a coloring pigment, a pigment dispersant, and light irradiation. Is a mixture of a photopolymerization initiator for initiating the polymerization reaction, a diluting solvent and the like. As the transparent support, glass is usually used, and preferably alkali-free glass is used. The black matrix is usually formed of a metal light-shielding film such as chromium or a resin film containing a black component such as carbon black, and is preferably formed using a photosensitive resin in which a black pigment is dispersed.

The contact angle of water in the present invention means a diameter of 1 to
It is the contact angle read by a direct-viewing method after a water drop of 2 mm was dropped most recently and 30 seconds later. The water used here is
Pure water having a specific resistance of 18 MΩ or more is used. The ozone treatment of the present invention may be basically performed before the application of the photosensitive resin, and more specifically, before forming the next color pixel on the surface having the black matrix or the color pixel. Done. Therefore, most completely, the black matrix formation, the first color pixel formation and the second color pixel formation may be performed three times, and if the stain in the non-colored area formed in the previous step is not a problem. If not, the processing at that point may be omitted. The treatment of the present invention on the support before the formation of the black matrix is usually unnecessary, but the present invention does not exclude it. The ozone treatment is usually carried out in a temperature environment close to room temperature, but in the present invention, it is preferably carried out in a temperature environment of 30 ° C. or higher. Regarding the ozone concentration, an appropriate concentration may be selected depending on the case as long as the object of the present invention is achieved,
The treatment is usually performed under a concentration condition of 1 ppm or more, more preferably 3 ppm or more. Also, regarding the processing time,
An appropriate time is set, but preferably 30 seconds or more,
More preferably, the treatment is performed for 1 minute or more. In order to prevent the adhesion of particles, which is the main cause of defects,
Usually, the ozone treatment is performed in a clean environment, preferably in an atmosphere in which the amount of particles of 0.5 μm is 1000 or less (class 1000) within 1 cubic foot, and more preferably 100 or less (class). 100) under the atmosphere. Further, the substrate to be processed is introduced into the ozone treatment tank by a single-wafer conveyance in which the substrate is sequentially introduced into the tank by a transfer means capable of transferring one by one, and the substrate is placed on the transfer means and sequentially transferred and withdrawn. While a method of continuously performing ozone treatment is preferably used industrially,
It is not limited to this.

Regarding the method of supplying ozone in the present invention, it is usually 254 nm and 185 nm, or 172 nm.
It is generated by decomposing oxygen in the air by UV irradiation having a wavelength of nm as the main wavelength, but UV of other wavelength may be used, and it may be supplied by another method such as arc discharge. Absent. Further, the ozone treatment in the present invention may be used in combination with other treatment methods, and as a result, the contact angle may satisfy the above conditions. Other treatment methods include, for example, wet cleaning with water, acid, alkali, detergent, etc., ultrasonic cleaning, megasonic cleaning, brush scrub cleaning,
Examples of the method include, but are not limited to, physical force cleaning such as cavitation jet, hot air drying, and far infrared ray drying. The treatment may be performed before or after the ozone treatment.

Although the reason why the adhesion between the photosensitive resin and the surface to be coated is lowered by the ozone treatment in the present invention is not clear yet, the surface of the coating is made hydrophilic by the ozone treatment and the photosensitive resin is hydrophobic. It is presumed that the ease of peeling is improved because the adhesion of the aqueous solution is deteriorated and, at the same time, the penetration of the aqueous developer is promoted. On the other hand, the contact angle of water is
Since it is an index showing the hydrophilicity of the surface, it is presumed that the surface condition, that is, the adhesion is controlled by controlling this.

[0016]

EXAMPLES Next, specific embodiments of the present invention will be described with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist thereof.

(Examples 1, 2 and Comparative Examples-1 to 3) A photosensitive resin containing acrylic resin as a main component and carbon black dispersed therein was 370 × 470 × 0.7 mmt (AN-635 manufactured by Asahi Glass). After uniformly coating the above glass plate with a film thickness of 1.0 μm by spin coating, exposure and development were performed to form a black matrix. Hot air drying was carried out at 200 ° C. for 10 minutes for the purpose of completely curing the black matrix. After this, an ozone atmosphere of 5 ppm was created by UV irradiation with the main wavelengths of 185 nm and 254 nm (the distance between the UV light source and the glass was 10 mm), and the substrate with the black matrix was placed on a horizontal transport roller as shown in Table-1. Substrates having different water contact angles were prepared by changing the passage time in the ozone atmosphere.

Table 1 shows the contact angles of the substrate surface obtained in each of these cases. The contact angle was measured by bringing the tip of the injection needle as close as possible to the glass surface, and by applying a specific resistance of about 1 mm to the peripheral edge of the glass plate, which has a sufficient exposed area of the glass surface.
A water drop of pure water of MΩ or more was dropped, and 30 seconds later, it was judged by a direct visual method. Substrates with black matrix thus treated with ozone (Examples 1 and 2, Comparative Examples 2 and 3) and substrates not treated with ozone (Comparative Example-
In 1), a photosensitive resin containing an acrylic resin as a main component and a red pigment dispersed therein was applied by spin coating to a film thickness of 1.5 μm, exposed and developed to form red pixels.
Table 2 shows the number of white chips and peelings having an area of 1000 μm ² or more on the red pixel and the amount of the residual photosensitive resin.

[0019]

[Table 1]

[0020]

[Table 2]

(Examples 3 to 4 and Comparative Examples 4 to 6) 3
70 x 470 x 0.7 mmt glass (AN- manufactured by Asahi Glass
635), a chromium oxide film is formed by sputtering to form a black matrix, and then a photosensitive resin containing an acrylic resin as a main component and a red pigment dispersed therein is uniformly applied by spin coating to a film thickness of 1.0 μm. Then, exposure and development were performed to form red pixels. Hot air drying was performed at 200 ° C. for 10 minutes for the purpose of curing the red pixels. After this, an ozone atmosphere of 5 ppm was created by UV irradiation with main wavelengths of 185 nm and 254 nm (the distance between the UV light source and the glass was 10 mm), and the substrate with red pixels was placed on a horizontal transport roller, as shown in Table-3. The treatment was performed by changing the passage time in the ozone atmosphere.

Table 3 shows the contact angles of the substrate surface obtained in each of these cases. On the substrate with red pixels thus treated with ozone (Examples 3 and 4, Comparative Examples 5 and 6) and the substrate not treated with ozone (Comparative Example 4),
A photosensitive resin containing an acrylic resin as a main component and a green pigment dispersed therein was applied by spin coating to a film thickness of 1.5 μm, and exposed and developed to form a green pixel. Table 4 shows the number of white chips and peelings having an area of 1000 μm ² or more on the green pixel and the amount of the residual photosensitive resin after forming the green pixel.

[0023]

[Table 3]

[0024]

[Table 4]

[0025]

According to the present invention, by controlling the contact angle of water with respect to the surface coated with the photosensitive resin in the ozone treatment, the residual of the photosensitive resin residue after development is suppressed and controlled. It is possible to improve the manufacturing yield of the product, which is a great advantage for industrial production.

Claims (8)

[Claims] 1. A color filter in which a black matrix is formed on a transparent support and color pixels are formed on the support by photolithography using a photosensitive resin in which red, green and blue pigments are dispersed. In the method for producing the above method, the surface to be coated is subjected to ozone treatment before the coating of the photosensitive resin, and the contact angle of water with respect to the non-pixel portion of the surface to be coated is 12 ° or more and 40 ° or less. Filter manufacturing method. 2. The method for producing a color filter according to claim 1, wherein the black matrix is formed by using a resin containing a black colorant. 3. The method for producing a color filter according to claim 1, wherein the ozone treatment is performed for 30 seconds or more in an atmosphere having an ozone concentration of 1 ppm or more and a temperature of 30 ° C. or more. 4. The ozone treatment is performed in an environment in which the amount of particles of 0.5 μm or more is 1000 or less in 1 cubic foot.
A method for producing the described color filter. 5. The ozone treatment is carried out while sequentially introducing and withdrawing the substrate to be treated into and out of an ozone atmosphere by a transport means for transporting the substrates one by one.
4. The method for producing a color filter according to 4. 6. The ozone supply is 254 nm and 1
The method for producing a color filter according to any one of claims 1 to 5, which is performed by UV irradiation having a main wavelength of 85 nm or 172 nm. 7. The method of manufacturing a color filter according to claim 6, wherein the UV irradiation is performed by setting the distance from the UV light source to the surface to be irradiated to 30 mm or less. 8. The method for producing a color filter according to claim 1, wherein the transparent support is glass.