JPH09101407A - Forming method for black matrix for color filter, substrate for formation and photoresist - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a fine black matrix having high light-shielding property at a low cost by forming a resist pattern on a glass substrate, applying a coating liquid containing a black color component, etching and developing. SOLUTION: A photoresist coating film on a glass substrate is irradiated with UV rays through a photomask having a desired pattern and developed to form a resist pattern. Then a coating liquid containing a black color component is applied on the whole surface of the glass substrate with the resist pattern formed. The obtd. black component coating material is etched and developed to form a black matrix for a color filter. As for the photoresist, a water-soluble photoresist containing polyvinyl pyrrolidone as a photosetting component and a water-soluble bisazide compd. as a photosensitive agent is preferably used. As for the coating liquid containing a black color component, a water dispersion liquid containing graphite in a fine power state or scale state and a water-soluble binder is preferably used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a black matrix for a color filter used in a color display device such as a color liquid crystal display or a plasma display, a solid-state image pickup device, a color image pickup device such as a color sensor.

[0002]

2. Description of the Related Art In recent years, color filters in which three primary colors (red, green, blue) are regularly arranged are used in a color liquid crystal display and a plasma display, which are attracting attention as flat displays. In order to enhance the coloring effect and contrast of this color filter, a black stripe-shaped or lattice-shaped black matrix is formed at the boundary between the three primary colors. This black matrix is required to have fine workability and high light-shielding property. Conventionally, as a method of forming a black matrix, a method of depositing metal chromium and etching it (chrome etching method), a method of patterning a hydrophilic resin and dyeing it (staining method), and dispersing a black component such as a pigment There is a method of photo-curing the above photoresist to form a pattern (pigment resist method), a method of forming a transparent electrode on which a pattern is formed by using an electrodeposition coating (electrodeposition method).

[0003]

However, although the chromium etching method is excellent in fine workability, the cost of the vacuum film forming process such as vapor deposition is high, and the reflectance of metallic chromium is high, so that it can be exposed to strong external light. There is a problem that the contrast is hard to increase. The dyeing method is 20 because the dye is weak to heat.
There is a problem that the color becomes light when heat of 0 ° C. or more is applied, and there is a problem that the heat treatment temperature in the subsequent color filter manufacturing process can be restricted. In the pigment resist method, if a large amount of the black component is dispersed in an attempt to increase the light-shielding property of the black matrix, it is difficult to obtain a sufficient amount of UV irradiation to cure the photoresist and it is difficult to form a pattern. There is a problem that the light-shielding property of the matrix becomes low. Further, the electrodeposition method has a problem that it is difficult to form a grid-like black matrix because the coating material is electrodeposited through the transparent electrode.

[0004]

Means for Solving the Problems The inventors of the present invention have made earnest studies to solve the problems of the conventional method for forming a black matrix for a color filter, and as a result, photoresist coating, ultraviolet irradiation (hereinafter referred to as exposure). ), Development, black component application, etching, development manufacturing process,
The present invention has been accomplished by finding a method capable of inexpensively forming a fine black matrix for a color filter having a high light-shielding property, a black matrix forming substrate for a color filter and a photoresist for forming a black matrix for a color filter, which are obtained by this method, and arrived at the present invention. .

That is, according to the present invention, a photoresist coating film on a glass substrate is irradiated with ultraviolet rays through a photomask having a desired pattern and developed to form a resist pattern, and the entire surface of the glass substrate on which the resist pattern is formed,
A method for forming a black matrix for a color filter, in which a black component coating material obtained through the step of applying a coating liquid containing a black component is subjected to an etching step and a developing step; a black matrix forming substrate for a color filter obtained by this method A photoresist for a black matrix forming step for a color filter, which comprises an ultraviolet-curable water-soluble photoresist; and a photoresist used in the method for forming a black matrix, wherein polyvinylpyrrolidone and a water-soluble bisazide compound are added in an amount of 100: 0.3-. It is a photoresist for a black matrix forming step for a color filter, which is contained in a weight ratio of 100: 15.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION In the method for forming a black matrix of the present invention, a halogen lamp,
A metal halide lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, etc. can be used, but an ultra-high-pressure mercury lamp is preferable. The exposure dose is usually 1 to 100 mJ / cm ² .

The initial film thickness of the photoresist coating film in the step (1) is preferably less than 1 μm, particularly preferably 0.1 μm to 0.5 μm. Below 0.1 μm,
A good black matrix may not be obtained in some cases because the photoresist photo-cured product is not sufficiently removed in the etching / developing process.

Examples of the photoresist used in the method for forming the black matrix of the present invention include organic solvent type photoresists and water-soluble photoresists. Here, the organic solvent-based photoresist refers to a photoresist containing an organic solvent, and the water-soluble photoresist is
It refers to a photoresist containing water as a solvent.

As the photo-curable component of the organic solvent type photoresist, cinnamic acid polyvinyl alcohol ester, cyclized rubber, polyvinyl phenol, polystyrene-maleic anhydride copolymer, phenol novolac resin, cresol novolac resin, epoxy resin, Poly (o-phthalaldehyde) resin, polyimide resin, acrylic monomer (alkyl acrylate, etc.), acrylic oligomer (polyester acrylate, polyether acrylate, urethane acrylate, epoxy acrylate, etc.), methacrylic monomer, methacrylic oligomer, etc. Can be given.

The organic solvent-based photoresist contains these photocurable components and, if necessary, a photosensitizer, trichloroethylene, trichloroethane, ethyl cellosolve acetate,
It is dissolved in a solvent such as ethyl lactate, ethyl-3-ethoxypropionate, and propylene glycol monomethyl ether acetate, and the content of the photocurable component is usually 0.05% by weight to 50% by weight.

As the photo-curable component of the water-soluble photoresist, polyvinylpyrrolidone and vinylpyrrolidone copolymers, polyvinyl alcohol and vinyl alcohol copolymers, styrylpyridinium resins, polyacrylamide and acrylamide copolymers, acrylamide- Examples thereof include diacetone acrylamide copolymer, maleic acid-vinyl methyl ether copolymer, methyl cellulose, hydroxypropyl cellulose, polyvinyl cellulose, polyethylene glycol, polyethylene glycol acrylate, polyacrylic acid and acrylic acid copolymer. The water-soluble photoresist is obtained by dissolving these photocurable components and, if necessary, a photosensitizer in water, and the content of the photocurable components is usually 0.05% by weight to 5%.
0% by weight.

If necessary, a surfactant may be added to the photoresist. By adding the surfactant, the wettability with respect to the glass substrate is improved. The surfactant is not particularly limited as long as it is compatible with each component, and examples thereof include an anionic surfactant, a nonionic surfactant, and a cationic surfactant. Preferred are nonionic surfactants (eg, sorbitan ester ethylene oxide adduct, alkylphenol ethylene oxide adduct, etc.). The amount of the surfactant added is usually 5% by weight or less based on the photocurable component, preferably 0.05.
~ 3% by weight.

If necessary, an adhesion improver can be added to the photoresist. Examples of the adhesion improver include a silane coupling agent and a titanium-based coupling agent, and preferably an amine-based silane coupling agent [for example, vinyl-tris- (β-methoxyethoxy)
Silane, N-β- (aminoethyl) -γ-aminopropylmethyldimethoxysilane, N-β- (aminoethyl)
-Γ-aminopropyltrimethoxysilane and the like], particularly preferably N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane. The amount of the adhesion improver added is usually 5% by weight or less, preferably 0.01 to 2% by weight, based on the photocurable component.

Examples of the photosensitizer optionally used in the photoresist include an azide compound, a bisazide compound, a naphthoquinonediazide, a dichromate, a diazo resin and a photocation generator, and a bisazide compound is preferable. As the bisazide compound, 2,6-bis (4,4′-diazidobenzal) -cyclohexanone,
Water-insoluble bisazide compounds such as 2,6-bis (4,4'-diazidobenzal) -4-methyl-cyclohexanone; and 4,4'-diazidobenzal-acetophenone-2-sulfonic acid, 4,4'-diazidobenzal-
Acetophenone-2-sodium sulfonate, 4,4 '
-Diazidostilbene-2,2'-disulfonic acid, 4,
Examples thereof include water-soluble bisazide compounds such as 4'-diazidostilbene-2,2'-sodium disulfonate, and water-soluble bisazide compounds are particularly preferable.

Among the photoresists exemplified above, a water-soluble photoresist is preferable, and a particularly preferable one is a water-soluble photoresist containing polyvinylpyrrolidone as a photocurable component and a water-soluble bisazide compound as a photosensitizer. is there.

When the water-soluble photoresist contains polyvinylpyrrolidone and a water-soluble bisazide compound, the content of polyvinylpyrrolidone is usually 0.05% by weight to 50% by weight, preferably 0.1% by weight to 20% by weight. % By weight. The weight ratio of polyvinylpyrrolidone to the water-soluble bisazide compound is preferably 100: 0.3 to 1
It is 00:15, and can be arbitrarily set within this range depending on the exposure conditions.

When the exposure is carried out under the condition that the exposure amount is 1 to 30 mJ / cm ² , the weight ratio of polyvinylpyrrolidone to the water-soluble bisazide compound is preferably 100: 1 to 100: 15. When the exposure is performed under the condition of the exposure amount of 30 to 100 mJ / cm ² , the weight ratio of polyvinylpyrrolidone and the water-soluble bisazide compound is preferably 100: 0.3 to 100: 5. Thus, if the weight ratio of polyvinylpyrrolidone and the water-soluble bisazide compound is set within the above range according to the exposure dose, the residual film ratio [the film thickness after exposure / development with respect to the photoresist initial film thickness (pre-exposure film thickness)] Ratio] is 40
% To 80%, whereby the photoresist photo-cured product is easily removed in the etching / developing process, and it becomes possible to form a black matrix having excellent linearity.

When the residual film ratio is 40% or less, the photocrosslinking density of the photocured product of the photoresist is low, so that the resist pattern is likely to fall off during exposure and development of the photoresist (called swelling). If it is 80% or more, the photocrosslinking density is too high, so that the photoresist photocured product is not sufficiently removed in the etching / developing process, and it is difficult to obtain a good black matrix.

In the step (1), the method of drying the photoresist when forming the coating film is not particularly limited as long as it does not affect the characteristics of the photoresist. For example, a method of drying with a hot plate, an infrared heater, a far infrared heater or the like is available. can give.

As the black component-containing coating liquid, it is possible to use a powder of graphite, a black pigment, a black dye, magnetic iron, manganese dioxide or the like as a black component, which is dispersed in water or a solvent together with a binder component. Is an aqueous dispersion containing graphite and a water-soluble binder in the form of fine powder or flakes and having an average particle size of 5 microns or less. Particularly preferred is an aqueous dispersion containing graphite and a water-soluble binder in the form of flakes and having an average particle size of 1 micron or less. By using graphite and a water-soluble binder, it is possible to form a black matrix that is firmly adhered to the glass substrate and has a high light-shielding property. Further, by using scaly graphite, it is possible to form a uniform thin film even with graphite having a relatively large particle size, and it is possible to form a black matrix having a high light-shielding property.

The content of the black component in the coating liquid containing the black component is usually 1% by weight to 50% by weight, preferably 3% by weight.
30% by weight. The black component-containing coating liquid preferably uses water as a solvent and contains a water-soluble binder. The water-soluble binder used for this purpose is not particularly limited as long as it does not affect the characteristics of the black component, and examples thereof include water glass, (meth) acrylic oligomer, polyethylene glycol, polyvinyl alcohol, polyvinylpyrrolidone, polyacrylamide, and methylcellulose. And the like, and particularly preferably water glass, (meth) acrylic oligomer, and polyethylene glycol. When a water-soluble binder is used in the black component-containing coating liquid, the content is usually 3% by weight to 70% by weight, preferably 5% by weight to 50% by weight.

Examples of the etching solution used in the etching step include hydrogen peroxide solution, alkaline aqueous solution (for example, sodium hydroxide aqueous solution), and the like, preferably hydrogen peroxide solution. The concentration of hydrogen peroxide water is preferably 1 to 10%. When hydrogen peroxide solution is used as the etching solution, a strong acid such as sulfuric acid may be added. The addition amount of sulfuric acid is usually 5% by weight or less, preferably 0.1% by weight to 2% by weight. The temperature of the etching solution is not particularly limited, but is usually 80 ° C or lower, preferably room temperature to 60 ° C.
It is. The etching time can be arbitrarily set depending on the etching solution temperature, the photoresist exposure conditions, etc., but is usually 5 seconds to 120 seconds, preferably 10 seconds to 60 seconds.

The light-shielding property of the black matrix is usually
Expressed as optical density (OD value). The OD value is defined as follows. The required performance of the OD value varies depending on the use of the color filter, but is usually 2.0 or more, preferably 3.
0 or more. OD value = Log (1 / transmittance), where transmittance = transmitted light amount / incident light amount

[0024]

EXAMPLES The present invention will be further described below with reference to examples, but the present invention is not limited thereto. Example 1 A photoresist solution having the composition shown in Table 1 was applied on a glass substrate by a spin coating method to a film thickness of 0.3 μm,
It was dried at 40 ° C. for 2 minutes on a hot plate to form a photoresist coating film. After that, using an ultra-high pressure mercury lamp,
Through a photomask with a line width of 20 μm, the exposure dose is 3 mJ /
After irradiating with cm ² of light, it was developed with water at room temperature to form a resist pattern. The residual film rate was 65%. The average grain size of 0.
An aqueous dispersion containing 8 μm of scaly graphite and water glass was applied to a film thickness of 0.8 μm by spin coating. Furthermore, the glass substrate treated with graphite is immersed for 30 seconds at room temperature in an etching solution containing 3% hydrogen peroxide and 0.2% sulfuric acid, and developed with water at room temperature to form the target black matrix. did. The black matrix formed by this method had an OD value of 4.0, which was an extremely high level. In addition, it is possible to form a black matrix with a line width of 20 μm that is extremely excellent in linearity,
The pattern forming ability was good.

[0025]

[Table 1]

Example 2 A photoresist solution having the composition shown in Table 2 was applied on a glass substrate by spin coating to a film thickness of 0.3 μm,
It was dried at 40 ° C. for 2 minutes on a hot plate to form a photoresist coating film. Then, using an ultra-high pressure mercury lamp, 2
Through a photomask with a line width of 0 μm, the exposure amount is 60 mJ /
After irradiating with cm ² of light, it was developed with water at room temperature to form a resist pattern. The residual film rate was 68%. The average grain size of 0.
An aqueous dispersion containing 8 μm of scaly graphite and water glass was applied to a film thickness of 0.8 μm by spin coating. Furthermore, the glass substrate treated with graphite is immersed for 30 seconds at room temperature in an etching solution containing 3% hydrogen peroxide and 0.2% sulfuric acid, and developed with water at room temperature to form the target black matrix. did. The black matrix formed by this method had an OD value of 3.9, which was an extremely high level. In addition, it is possible to form a black matrix with a line width of 20 μm that has extremely excellent linearity
The pattern forming ability was good.

[0027]

[Table 2]

Example 3 A photoresist solution having the composition shown in Table 3 was applied on a glass substrate by spin coating to a film thickness of 0.5 μm,
It was dried at 40 ° C. for 2 minutes on a hot plate to form a photoresist coating film. Then, using an ultra-high pressure mercury lamp, 2
Through a photomask with a line width of 0 μm, the exposure dose is 50 mJ /
After irradiating with light of cm ² , it was developed with trichloroethylene to form a resist pattern. The residual film rate was 59%. On the entire surface of the glass substrate on which this pattern was formed, scaly graphite having an average particle diameter of 0.8 μm and a water glass-containing water dispersion liquid were applied by a spin coating method to a film thickness of 0.8 μm. Further, the glass substrate treated with graphite was immersed in an etching solution in which a 5% aqueous sodium hydroxide solution was adjusted to a temperature of 50 ° C. for 30 seconds and developed with water at room temperature to form a target black matrix. The light-shielding property of the black matrix formed by this method is O
The D value was 3.7, which was an extremely high level. Also,
A black matrix having a line width of 20 μm having excellent linearity could be formed, and the pattern forming ability was good.

[0029]

[Table 3]

Comparative Example 1 A black pigment-containing photoresist having the composition shown in Table 4 was applied on a glass substrate by a spin coating method to a film thickness of 1.5 μm, and dried on a hot plate at 40 ° C. for 2 minutes. A photoresist coating film was formed. Then, using an ultrahigh pressure mercury lamp, light having an exposure amount of 150 mJ / cm ² was irradiated through a photomask having a line width of 20 μm, and then developed with a 0.25N sodium hydroxide aqueous solution to form a target black matrix. The light-shielding property of the black matrix formed by this method was 2.4 as the OD value, but the pattern was destroyed and the intended black matrix could not be formed.

[0031]

[Table 4]

Comparative Example 2 In the same manner as in Comparative Example 1, only the exposure amount was 250 mJ / cm 2.
^A black matrix was formed under the condition of ² . However, the pattern distortion was strong, and some patterns were missing.

Comparative Example 3 A black pigment-containing photoresist containing 10 parts by weight of carbon black was prepared, and a black matrix was formed in the same manner as in Comparative Example 1. However, the OD value was 1.0 or less, the light-shielding property was poor, and the pattern shape was distorted.

[0034]

The method for forming a black matrix for a color filter of the present invention has the following effects. 1) Since the photoresist and the black component are applied separately,
Unlike the case of applying a photoresist in which a black component is dispersed as in the past, it is possible to increase the content of the black component in the black component-containing coating liquid, unlike the conventional case,
It is possible to enhance the light-shielding property without being affected by the exposure conditions for the photoresist coating film. 2) It is possible to select a heat-stable black component such as graphite, and it is possible to form a black matrix having good heat resistance. 3) Normally, the thinner the initial film thickness of a photoresist, the more the linearity of the resist pattern improves. However, when a conventional photoresist in which a black component is dispersed is used, a thin film of less than 1 μm will block light. There was a problem that the quality did not increase. On the other hand, in the method of the present invention,
Since the photoresist and the black component are separately applied, the initial film thickness of the photoresist can be set as thin as less than 1 μm. Therefore, it is possible to form a black matrix having excellent linearity and a high light-shielding property. 4) When polyvinylpyrrolidone is used as the photocurable component of the photoresist used in the method of the present invention and a water-soluble bisazide compound is used as the photosensitizer, the ratio of both is 1 to 100 mJ / cm ^2. It can be used as a photoresist that forms a black matrix with excellent linearity under a wide exposure condition. Therefore, the usefulness of the method of the present invention, the black matrix-forming substrate obtained by this method, and the photoresist for the black matrix-forming step of the present invention is extremely high.

Claims (10)

[Claims] 1. A resist pattern forming step of irradiating a photoresist coating film on a glass substrate with ultraviolet rays through a photomask having a desired pattern to develop the resist coating film, and covering the entire surface of the glass substrate on which the resist pattern is formed,
A method for forming a black matrix for a color filter, which comprises subjecting a black component coating product obtained through the step of applying a coating liquid containing a black component to an etching step and a developing step. 2. The initial film thickness of the photoresist coating film is 1
The method according to claim 1, wherein the thickness is less than μm. 3. The forming method according to claim 1, wherein the residual film rate of the photoresist after being irradiated with ultraviolet rays and developed is 40% to 80%. 4. The formation method according to claim 1, wherein the black component-containing coating liquid is an aqueous dispersion liquid containing fine powdery or scaly graphite and a water-soluble binder. 5. A black matrix forming substrate for a color filter obtained by the method according to claim 1. 6. A photoresist for a black matrix forming step for a color filter, which is composed of an ultraviolet curable water-soluble photoresist. 7. The photoresist for a black matrix forming process according to claim 6, wherein the water-soluble photoresist comprises polyvinylpyrrolidone and a water-soluble bisazide compound. 8. A photoresist used in the method for forming a black matrix according to claim 1.
Polyvinylpyrrolidone and water-soluble bisazide compound 10
A photoresist for forming a black matrix for a color filter, which is contained in a weight ratio of 0: 0.3 to 100: 15. 9. The ultraviolet irradiation amount in the black matrix forming step is 1 mJ / cm ^{2 to} 30 mJ / cm ² , and the weight ratio of polyvinylpyrrolidone to the water-soluble bisazide compound is 100: 1 to 100: 15. For the black matrix forming process of. 10. The ultraviolet irradiation amount in the black matrix forming step is 30 mJ / cm ^{2 to} 100 mJ / cm ^2.
9. The photoresist for a black matrix forming process according to claim 8, wherein the weight ratio of polyvinylpyrrolidone to the water-soluble bisazide compound is 100: 0.3 to 100: 5.