JP2007249005A - Radiation-sensitive resin composition, spacer for liquid crystal display panel, method for forming spacer for liquid crystal display panel, and liquid crystal display panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radiation-sensitive resin composition which has a sufficient process margin, makes it possible to obtain a satisfactory spacer shape and film thickness with an exposure amount of ≤1,500 J/m<SP>2</SP>, and forms spacers for a display panel having high flexibility under compressive load, excellent also in adhesion, rubbing resistance and heat resistance, and excellent in resistance to a stripping solution. <P>SOLUTION: The radiation-sensitive resin composition useful for spacers for a liquid crystal display panel contains (A) a copolymer of (a1) an ethylenically unsaturated carboxylic acid and/or an ethylenically unsaturated carboxylic acid anhydride and (a2) another ethylenically unsaturated compound, (B) a polymerizable compound consisting mainly of (b1) tri- or higher functional (meth)acrylic esters and (b2) an ethylenically unsaturated compound other than the (b1), and (C) a radiation-sensitive polymerization initiator. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a radiation-sensitive resin composition, a spacer for a liquid crystal display panel, a method for forming a spacer for a liquid crystal display panel, and a liquid crystal display panel, and more specifically, a spacer used for a display panel such as a liquid crystal display panel or a touch panel. The present invention relates to a radiation-sensitive resin composition suitable as a material for forming the liquid crystal, a spacer for a liquid crystal display panel formed from the composition, a method for forming the liquid crystal display panel, and a liquid crystal display panel including the spacer.

Conventionally, liquid crystal display panels have used spacer particles such as glass beads and plastic beads having a predetermined particle size in order to keep the distance (cell gap) between two substrates constant. Since particles are randomly distributed on a transparent substrate such as a glass substrate, the presence of spacer particles in the pixel formation region may cause a phenomenon of spacer particle reflection or scattering of incident light, resulting in a contrast of the liquid crystal panel. There was a problem of lowering.
In order to solve these problems, a method of forming a spacer by photolithography has been adopted. In this method, a radiation-sensitive resin composition is applied onto a substrate, exposed to ultraviolet rays through a predetermined mask, and then developed to form dot-shaped or stripe-shaped spacers. Since the spacer can be formed only at a predetermined position, the above-described problem is basically solved.

In recent years, the mother glass substrate has been increased in size (for example, about 1,500 × 1,800 mm, and further about 1,870 × 2,200 mm) from the viewpoint of increasing the area of the liquid crystal display element and improving productivity. . However, with the conventional substrate size, the substrate size is smaller than the mask size, so it was possible to cope with the batch exposure method. However, with a large substrate, it is almost impossible to produce a mask size comparable to this substrate size. It is possible, and it is difficult to cope with the batch exposure method.
Therefore, a step exposure method has been proposed as an exposure method that can be applied to a large substrate. However, in the step exposure method, since a single substrate is exposed several times, and each exposure requires time for alignment and step movement, reduction of throughput is regarded as a problem compared to the batch exposure method. .
In addition, the collective exposure method allows an exposure amount of about 3,000 J / m ² , but the step exposure method requires a lower exposure amount each time, which is a conventional method used for forming a spacer. In the radiation-sensitive resin composition, it has been difficult to achieve a sufficient spacer shape and film thickness with an exposure amount of 1,500 J / m ² or less.

Therefore, in order to solve such a problem, the applicant of the present patent application has already disclosed in Patent Document 1 that the design size of the mask pattern can be faithfully reproduced with high sensitivity and has excellent adhesion to the substrate. A radiation-sensitive resin composition that can provide a spacer for a display panel that can form a sufficient spacer with an exposure amount of m ² or less and that is excellent in compressive strength, rubbing resistance, etc. has been clarified.

JP 2005-227525 A

By the way, in recent years, from the viewpoint of improving productivity, a process technique “ODF (One Drop Fill) method” in which a liquid crystal material is put on the glass surface before the glass of the liquid crystal panel is bonded is introduced.
This approach can save a lot of time. For example, in the conventional method, it takes about 5 days to fill the liquid crystal for a 30-inch panel. However, if the ODF method is introduced, only 2 hours are required, and the productivity can be greatly improved.
In the conventional bonding method, since a load is applied when the TFT array and the color filter are bonded together, the spacer is pressed evenly by the load, and the height uniformity of the spacer is maintained. However, in the ODF method, the initial bonding load is smaller than the conventional method because the bonding is performed only by the load due to the weight of the substrate and the atmospheric pressure. Therefore, even if the spacer is pushed with a small load, it is important to develop height uniformity by being pushed evenly. For this purpose, the flexibility of the spacer is required. If the height of the spacer is not uniform, the cell gap cannot be kept uniform, causing a gap in the cell and causing display unevenness. Therefore, a spacer material having high flexibility due to compressive load is required.

  In addition, the required values for the controllability of the spacer shape and film thickness have become increasingly severe in recent years, accompanying the shape and film thickness variation due to process variations when forming the spacer, and the composition solution over time. , Problems remained with respect to stability of shape and film thickness. Furthermore, radiation-sensitive resin compositions used in recent liquid crystal display panel manufacturing have become serious problems such as contamination during the storage period and the occurrence of foreign substances due to crystallization of components in the composition during use. Therefore, a radiation sensitive resin composition with reduced such problems has been desired.

It is an object of the present invention to have a sufficient process margin, to obtain a sufficient spacer shape and film thickness with an exposure amount of 1,500 J / m ² or less, to have a high flexibility due to a compressive load, and to adhere Another object of the present invention is to provide a radiation-sensitive resin composition that is excellent in rubbing resistance, heat resistance, and the like and can form a display panel spacer excellent in peeling liquid resistance.

According to the present invention, the above problem is firstly
(A) a copolymer of (a1) an ethylenically unsaturated carboxylic acid and / or an ethylenically unsaturated carboxylic acid anhydride and (a2) another ethylenically unsaturated compound,
(B) (b1) a trifunctional or higher-functional (meth) acrylic acid ester and (b2) a polymerizable compound mainly comprising another ethylenically unsaturated compound other than (b1), and (C) radiation sensitivity. This is achieved by a radiation sensitive resin composition characterized by containing a polymerization initiator.
Here, (b1) a trifunctional or higher functional (meth) acrylic acid ester is dipentaerythritol hexaacrylate, and (b2) another ethylenically unsaturated compound is (α) a polyfunctional isocyanate compound, (Β) A polyfunctional urethane acrylate having a weight average molecular weight of 15,000 or less obtained by reacting a (meth) acrylate compound containing one hydroxyl group in the molecule and (γ) polyol is preferred.

According to the present invention, the above problem is secondly,
(C) The radiation-sensitive polymerization initiator is achieved by a radiation-sensitive resin composition in which at least one is an O-acyloxime type polymerization initiator.

According to the present invention, the above problem is thirdly,
It is achieved by a radiation-sensitive resin composition (hereinafter referred to as “a radiation-sensitive resin composition for a liquid crystal display panel spacer”) used for forming a spacer for a liquid crystal display panel, comprising the radiation sensitive resin composition. .

According to the present invention, the above problem is fourthly,
This is achieved by a spacer for a liquid crystal display panel formed from a radiation sensitive resin composition for a spacer for a liquid crystal display panel.

According to the present invention, fifthly, the above problem is
This is achieved by a method for forming a spacer for a liquid crystal display panel, comprising at least the following steps in the order described below.
(A) A step of forming a film of the radiation-sensitive resin composition described above on a substrate.
(B) A step of exposing at least a part of the coating.
(C) A step of developing the film after exposure.
(D) A step of heating the coated film after development.

The radiation-sensitive resin composition of the present invention has high sensitivity, can faithfully reproduce the design size of the mask pattern, has excellent adhesion to the substrate, and has a sufficient spacer shape with an exposure amount of 1,500 J / m ² or less. It is possible to obtain a film thickness, and is excellent in strength, heat resistance, etc., excellent in the shape of the spacer and the film thickness in a low exposure amount region, and hardly generates foreign matters during storage and use.

Hereinafter, the present invention will be described in detail.
Radiation-sensitive resin composition- (A) copolymer-
The (A) copolymer can be produced by radical polymerization of the above components (a1) and (a2) in a solvent in the presence of a polymerization initiator.

  (A) Among the components constituting the copolymer, (a1) ethylenically unsaturated carboxylic acid and / or ethylenically unsaturated carboxylic acid anhydride (hereinafter collectively referred to as “(a1) unsaturated carboxylic acid type” Monomers "such as acrylic acid, methacrylic acid, crotonic acid, 2-methacryloyloxyethyl succinic acid, 2-methacryloyloxyethyl hexahydrophthalic acid; maleic acid, fumaric acid Examples thereof include dicarboxylic acids such as acid, citraconic acid, mesaconic acid and itaconic acid; anhydrides of the above dicarboxylic acids.

Among these (a1) unsaturated carboxylic acid-based monomers, acrylic acid, methacrylic acid, maleic anhydride are available from the viewpoints of copolymerization reactivity, solubility of the resulting copolymer in an alkaline aqueous solution, and easy availability. 2-methacryloyloxyethyl hexahydrophthalic acid is preferred.
In the copolymer (A), the (a1) unsaturated carboxylic acid monomer can be used alone or in admixture of two or more.

  In the copolymer (A), the content of repeating units derived from the (a1) unsaturated carboxylic acid monomer is preferably 5 to 50% by weight, more preferably 10 to 40% by weight, and particularly preferably 15%. ~ 30% by weight. In this case, if the content of the repeating unit derived from the (a1) unsaturated carboxylic acid monomer is less than 5% by weight, the solubility in an alkaline aqueous solution tends to decrease, whereas if it exceeds 50% by weight There is a possibility that the solubility in an aqueous alkali solution becomes too large.

Examples of (a2) other ethylenically unsaturated compounds (hereinafter simply referred to as “(a2) other monomers”) include acrylic acid alkyl esters such as methyl acrylate and i-propyl acrylate. Alkyl methacrylates such as methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, sec-butyl methacrylate, t-butyl methacrylate; cyclohexyl acrylate, 2-methylcyclohexyl acrylate, tricycloacrylate [5 .2.1.0 ^2,6 ] decan-8-yl, acrylic acid 2- (tricyclo [
5.2.1.0 ^2,6 ] decan-8-yloxy) ethyl, acrylic alicyclic esters such as isobornyl acrylate; cyclohexyl methacrylate, 2-methylcyclohexyl methacrylate, tricyclomethacrylate [
5.2.1.0 ^2,6 ] Decan-8-yl, methacrylic acid 2- (tricyclo [
5.2.1.0 ^2,6 ] Decan-8-yloxy) ethyl, methacrylic acid alicyclic esters such as isobornyl methacrylate; aryl acrylates or aralkyl esters of acrylic acid such as phenyl acrylate and benzyl acrylate Aryl esters or aralkyl esters of methacrylic acid such as phenyl methacrylate and benzyl methacrylate; dicarboxylic acid dialkyl esters such as diethyl maleate, diethyl fumarate and diethyl itaconate; 2-hydroxyethyl methacrylate, 2-methacrylic acid 2- Hydroxyalkyl methacrylates such as hydroxypropyl; one oxygen atom such as tetrahydrofurfuryl methacrylate, tetrahydrofuryl methacrylate, tetrahydrofupyran-2-methyl methacrylate, etc. Unsaturated hetero 5- and 6-membered methacrylic acid esters; glycidyl acrylate, 2-methylglycidyl acrylate, 3,4-epoxybutyl acrylate, 6,7-epoxyheptyl acrylate, 3,4-epoxy acrylate Epoxy alkyl esters of acrylic acid such as cyclohexyl; methacrylic acid such as glycidyl methacrylate, 2-methylglycidyl methacrylate, 3,4-epoxybutyl methacrylate, 6,7-epoxyheptyl methacrylate, 3,4-epoxycyclohexyl methacrylate Α-alkyl acrylate epoxies such as glycidyl α-ethyl acrylate, glycidyl α-n-propyl acrylate, glycidyl α-n-butyl acrylate, 6,7-epoxyheptyl α-ethyl acrylate, etc. Al Kill esters; glycidyl ethers such as o-vinylbenzyl glycidyl ether, m-vinylbenzyl glycidyl ether, p-vinylbenzyl glycidyl ether; styrene, α-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxy Vinyl aromatic compounds such as styrene; phenylmaleimide, cyclohexylmaleimide, benzylmaleimide, N-succinimidyl-3-maleimidobenzoate, N-succinimidyl-4-maleimidobutyrate, N-succinimidyl-6-maleimidocaproate, N-succinimidyl Dicarbonylimide derivatives such as -3-maleimidopropionate and N- (9-acridinyl) maleimide; 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butyl In addition to the conjugated diene compound such as a diene, acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, vinyl chloride, vinylidene chloride, vinyl acetate, and the like.

Among these (a2) other monomers, 2-methylcyclohexyl acrylate, hydroxyethyl methacrylate, benzyl methacrylate, methacrylic acid from the viewpoint of copolymerization reactivity and solubility of the resulting copolymer in an alkaline aqueous solution. N-Butyl acid, tricyclomethacrylate [5.2.1.0 ^2,6 ]
Decan-8-yl, styrene, glycidyl methacrylate, tetrahydrofurfuryl methacrylate, 1,3-butadiene and the like are preferable.
In the copolymer (A), (a2) other monomers can be used alone or in admixture of two or more.

  The (A) copolymer used in the present invention is preferably (a2) a constituent unit derived from another monomer, preferably 95 to 50% by weight, more preferably 90 to 60% by weight, particularly preferably 85. ˜70 wt% [however, (a1) + (a2) = 100 wt% above]. In this case, when the structural unit of (a2) is less than 50% by weight, the storage stability of the (A) copolymer tends to decrease, whereas when it exceeds 95% by weight, the copolymer (A) It becomes difficult to dissolve in an alkaline aqueous solution.

As described above, the (A) copolymer used in the present invention has a carboxyl group and / or a carboxylic anhydride group and has appropriate solubility in an aqueous alkali solution.
The radiation-sensitive resin composition containing the (A) copolymer exhibits good alkali solubility during development and can easily form a spacer having a predetermined pattern.

  (A) As a solvent used for manufacture of a copolymer, alcohol, ether, glycol ether, ethylene glycol alkyl ether acetate, diethylene glycol, dipropylene glycol, propylene glycol monoalkyl ether, propylene glycol alkyl ether acetate, propylene glycol, for example Examples include alkyl ether propionates, aromatic hydrocarbons, ketones and esters.

Specific examples thereof include alcohols such as methanol, ethanol, benzyl alcohol, 2-phenylethyl alcohol, and 3-phenyl-1-propanol;
Ethers such as tetrahydrofuran;
Examples of glycol ethers include ethylene glycol monomethyl ether and ethylene glycol monoethyl ether;
Examples of ethylene glycol alkyl ether acetate include methyl cellosolve acetate, ethyl cellosolve acetate, ethylene glycol monobutyl ether acetate, and ethylene glycol monoethyl ether acetate;
Examples of diethylene glycol include diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, and diethylene glycol ethyl methyl ether.
Examples of dipropylene glycol include dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether, and dipropylene glycol ethyl methyl ether;
Examples of propylene glycol monoalkyl ethers include propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether;
Examples of propylene glycol alkyl ether acetates include propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, propylene glycol propyl ether acetate, propylene glycol butyl ether acetate;
As propylene glycol alkyl ether propionate, for example, propylene glycol methyl ether propionate, propylene glycol ethyl ether propionate, propylene glycol propyl ether propionate, propylene glycol butyl ether propionate, etc .;
Aromatic hydrocarbons such as toluene, xylene, etc .;
Examples of ketones include methyl ethyl ketone, cyclohexanone, 4-hydroxy-4-methyl-2-pentanone, etc .;

Examples of esters include methyl acetate, ethyl acetate, propyl acetate, butyl acetate, ethyl 2-hydroxypropionate, methyl 2-hydroxy-2-methylpropionate, ethyl 2-hydroxy-2-methylpropionate, methyl hydroxyacetate, hydroxy Ethyl acetate, hydroxybutyl acetate, methyl lactate, ethyl lactate, propyl lactate, butyl lactate, methyl 3-hydroxypropionate, ethyl 3-hydroxypropionate, propyl 3-hydroxypropionate, butyl 3-hydroxypropionate, 2-hydroxy -3-methylbutanoate, methyl methoxyacetate, ethyl methoxyacetate, propyl methoxyacetate, butyl methoxyacetate, methyl ethoxyacetate, ethyl ethoxyacetate, propyl ethoxyacetate, butyl ethoxyacetate, propoxy Methyl acetate, ethyl propoxyacetate, propyl propoxyacetate, butyl propoxyacetate, methyl butoxyacetate, ethyl butoxyacetate, propyl butoxyacetate, butylbutoxyacetate, 3-methoxybutyl acetate, methyl 2-methoxypropionate, ethyl 2-methoxypropionate Propyl 2-methoxypropionate, butyl 2-methoxypropionate, methyl 2-ethoxypropionate, ethyl 2-ethoxypropionate, propyl 2-ethoxypropionate, butyl 2-ethoxypropionate, methyl 2-butoxypropionate, Ethyl 2-butoxypropionate, propyl 2-butoxypropionate, butyl 2-butoxypropionate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, 3-methoxypropionic acid Lopyl, butyl 3-methoxypropionate, methyl 3-ethoxypropionate, ethyl 3-ethoxypropionate, propyl 3-ethoxypropionate, butyl 3-ethoxypropionate, methyl 3-propoxypropionate, ethyl 3-propoxypropionate , Esters of propyl 3-propoxypropionate, butyl 3-propoxypropionate, methyl 3-butoxypropionate, ethyl 3-butoxypropionate, propyl 3-butoxypropionate, butyl 3-butoxypropionate, etc. it can.

Of these, ethylene glycol alkyl ether acetate, diethylene glycol, dipropylene glycol, propylene glycol monoalkyl ether, and propylene glycol alkyl ether acetate are preferred. Among them, diethylene glycol dimethyl ether, diethylene glycol ethyl methyl ether, dipropylene glycol dimethyl ether, dipropylene glycol ethyl Particularly preferred are methyl ether, propylene glycol methyl ether, propylene glycol methyl ether acetate, and 3-methoxybutyl acetate.
The said solvent can be used individually or in mixture of 2 or more types.
In addition, the usage-amount of the said solvent is 80-400 weight part normally with respect to 100 weight part of monomer components which consist of (a1)-(a2) component, Preferably it is about 100-300 weight part.

The radical polymerization initiator used for the polymerization is not particularly limited. For example, 2,2′-azobisisobutyronitrile, 2,2′-azobis- (2,4-dimethylvalero) Nitrile), 2,2′-azobis- (4-methoxy-2,4-dimethylvaleronitrile), 4,4′-azobis (4-cyanovaleric acid), dimethyl 2,2′-azobis (2-methylpro) Azo compounds such as pionate), 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile); benzoyl peroxide, lauroyl peroxide, t-butylperoxypivalate, 1,1-bis (t-butyl) Organic peroxides such as peroxy) cyclohexane; hydrogen peroxide and the like. Moreover, when using a peroxide as a radical polymerization initiator, it is good also as a redox type initiator combining it and a reducing agent.
These radical polymerization initiators can be used alone or in admixture of two or more.
In addition, the usage-amount of the said radical polymerization initiator is 0.5-10 weight part normally with respect to 100 weight part of monomer components which consist of (a1)-(a2) component, Preferably it is about 1-8 weight part. It is.
The above radical polymerization usually has a polymerization temperature of 60 to 100 ° C., preferably 70 to 90 ° C., and a polymerization time of 120 to 420 minutes, preferably about 180 to 360 minutes.
The copolymer (A) thus obtained may be used for the preparation of the radiation sensitive resin composition in the form of a solution, or may be separated from the solution and used for the preparation of the radiation sensitive resin composition.

  (A) The polystyrene-converted weight average molecular weight (hereinafter referred to as “Mw”) by gel permeation chromatography (GPC) of the copolymer is usually 2,000 to 100,000, preferably 5,000 to 50,000. It is. In this case, if the Mw is less than 2,000, the developability and the remaining film ratio of the resulting film may be reduced, and the pattern shape, heat resistance and the like may be impaired. , There is a possibility that the resolution is lowered or the pattern shape is damaged.

-(B) Polymerizable compound-
Component (B) in the radiation-sensitive resin composition is a polymerization mainly composed of (b1) trifunctional or higher functional (meth) acrylic acid esters and (b2) other ethylenically unsaturated compounds other than (b1). It is a sex compound. Here, (b1) trifunctional or higher functional (meth) acrylic acid esters include dipentaerythritol hexaacrylate, and (b2) other ethylenic compounds include (α) a polyfunctional isocyanate compound, ( β) A polyfunctional urethane acrylate having a weight average molecular weight of 15,000 or less obtained by reacting a (meth) acrylate compound containing one hydroxyl group in the molecule with (γ) polyol is preferred.

Examples of the (b1) trifunctional or higher functional (meth) acrylic acid esters include trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol triacrylate, pentaerythritol trimethacrylate, pentaerythritol tetraacrylate, pentaerythritol tetra Methacrylate, dipentaerythritol pentaacrylate, dipentaerythritol pentamethacrylate, dipentaerythritol hexaacrylate, dipentaerythritol hexamethacrylate, tri (2-acryloyloxyethyl) phosphate, tri (2-methacryloyloxyethyl) phosphate, etc. Particularly preferably dipentaerythritol hexaacrylate It is a DPHA).
As said commercial item, for example, Aronix M-309, M-400, M-405, M-450, M-7100, M-8030, M-8060, M-8060, TO-1382, TO- 1450 (manufactured by Toa Gosei Co., Ltd.), KAYARAD TMPTA, DPHA, DPCA-20, DPCA-30, DPCA-60, DPCA-60, DPCA-120 (manufactured by Nippon Kayaku Co., Ltd.), Biscote 295, 300 360, GPT, 3PA, 400 (manufactured by Osaka Organic Chemical Industry Co., Ltd.).

  (B2) Other ethylenic compounds are not particularly limited, but monofunctional, bifunctional, or trifunctional or higher (meth) acrylic urethanes (polyfunctional urethane acrylates), (meth) acrylic. Acid esters (excluding the component (b1) above) are preferred from the viewpoint of good polymerizability.

  Of these, as (meth) acrylic acid urethanes, (α) a polyfunctional isocyanate compound, (β) a (meth) acrylate compound containing one hydroxyl group in the molecule, and (γ) polyol are reacted. The polyfunctional urethane acrylate obtained is mentioned.

The (α) polyfunctional isocyanate compound as a constituent material of the polyfunctional urethane acrylate includes 2,3-tolylene diisocyanate, 2,4-tolylene diisocyanate, 2,5-tolylene diisocyanate, and 2,6-tolylene diene. Isocyanate, 1,2-ethylene diisocyanate, 1,3-trimethylene diisocyanate, 1,4-tetramethylene diisocyanate, 1,5-pentamethylene diisocyanate, 1,6-hexamethylene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, iso Foron diisocyanate, 1,2-phenylene diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, xylene diisocyanate, cyclohexane dii Cyanate, 2,5-bis (isocyanatomethyl) bicyclo [2.2.1]
Examples include heptane and 2,6-bis (isocyanatomethyl) bicyclo [2.2.1] heptane.

  Among these (α) polyfunctional isocyanate compounds, 2,3-tolylene diisocyanate, isophorone diisocyanate, 1,6-hexadiene from the viewpoint of compatibility of the resulting polyfunctional urethane acrylate with the radiation-sensitive resin composition. Methylene diisocyanate, 1,3-phenylene diisocyanate and the like are preferable. These may be used alone or in combination of two or more.

  Further, (β) a (meth) acrylate compound containing one hydroxyl group in the molecule includes 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 3-hydroxypropyl acrylate, 3-hydroxypropyl methacrylate, 4-hydroxy Examples include butyl acrylate, 4-hydroxybutyl methacrylate, caprolactone-modified 2-hydroxyethyl acrylate, polyethylene glycol monoacrylate, polypropylene glycol monoacrylate, pentaerythritol triacrylate, and dipentaerythritol pentaacrylate.

  Of the (meth) acrylate compounds containing one hydroxyl group in the (β) molecule, 2-hydroxyethyl acrylate, 3-hydroxypropyl acrylate, Pentaerythritol triacrylate and the like are preferable. These may be used alone or in combination of two or more.

  Furthermore, examples of the (γ) polyol include polyether polyol, polyester polyol, polycarbonate polyol, polycaprolactone polyol, and the like. Among these, polyether polyol is preferable from the viewpoint of imparting flexibility to the radiation-sensitive resin composition using the obtained polyfunctional urethane acrylate. Of these polyether polyols, polyethylene glycol and polypropylene glycol having a weight average molecular weight of 10,000 or less are particularly preferred.

  The (α) polyfunctional isocyanate compound, (β) a (meth) acrylate compound containing one or more hydroxyl groups in the molecule, and (γ) polyol are (α) isocyanate group, (β) hydroxyl group and (γ ) With a hydroxyl group in the range of 1.00 / 1.00 / 0.50 to 1.00 / 1.20 / 0.60, preferably 1.00 / 1.00 / 0.50. It is preferable to make it react in the ratio which becomes the range of 1.00 / 1.10 / 0.55. When the molar ratio of hydroxyl groups is less than 1.00 with respect to the molar ratio of isocyanate groups, unreacted isocyanate groups remain in the resulting polyfunctional urethane acrylate, and the storage stability of the radiation-sensitive resin composition using the same Tend to decrease. Moreover, when the molar ratio of a hydroxyl group is larger than 1.20 with respect to the molar ratio of an isocyanate group, an excess hydroxyl group remains and there exists a tendency for the storage stability of the radiation sensitive resin composition using the hydroxyl group to fall.

The polyfunctional urethane acrylate can be synthesized by a known method, and a predetermined amount of (α) polyfunctional isocyanate compound and (β) (meth) acrylate compound containing one or more hydroxyl groups in the molecule. , And (γ) polyol is charged all at once, and is heated and stirred at 60 ° C. to 100 ° C. until free isocyanate groups disappear. The reaction time is usually about 60 to 240 minutes.
In addition, a catalyst such as hydroquinone monomethyl ether or dibutyltin dilaurate (IV) may be added as necessary during the reaction, and hydroquinone, p-benzoquinone, t-butylcatechol, etc. to prevent gelation due to dark reaction during storage. May be added.
The above polyfunctional urethane acrylate has a weight average molecular weight of 15,000 or less, preferably 6,000 to 12,000. When the weight average molecular weight exceeds 15,000, the solubility in a developing solution is lowered, which is not preferable.

  Commercially available products of the polyfunctional urethane acrylate include KAYARAD UX-2201, UX-2301, UX-3204, UX-3301, UX-4101, UX-6101, UX-7101, UX-8101, UX-101 0937 (above, Nippon Kayaku Co., Ltd.), Art Resin UN-9000PEP, UN-9200A (above, Negami Kogyo Co., Ltd.), and the like.

  As (b2) ethylenically unsaturated compounds other than the above polyfunctional urethane acrylates, monofunctional, bifunctional, or trifunctional or higher (meth) acrylic urethanes (however, excluding the above polyfunctional urethane acrylates), (meta ) Acrylic acid esters (excluding the above component (b1)).

  Examples of the monofunctional (meth) acrylic acid esters include 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, diethylene glycol monoethyl ether acrylate, diethylene glycol monoethyl ether methacrylate, isobornyl acrylate, isobornyl methacrylate, ω -Carboxy-polycaprolactone monoacrylate, 3-methoxybutyl acrylate, 3-methoxybutyl methacrylate, (2-acryloyloxyethyl) (2-hydroxypropyl) phthalate, (2-methacryloyloxyethyl) (2-hydroxypropyl) phthalate, etc. Moreover, as a commercial item, it is a brand name, for example, Aronix M-101, M-111, M-114, M-53. 0 (above, manufactured by Toa Gosei Co., Ltd.); KAYARAD TC-110S, TC-120S (above, manufactured by Nippon Kayaku Co., Ltd.); Biscote 158, 2311 (above, manufactured by Osaka Organic Chemical Industry Co., Ltd.) And so on.

  Examples of the bifunctional (meth) acrylic acid esters include ethylene glycol diacrylate, ethylene glycol dimethacrylate, diethylene glycol diacrylate, diethylene glycol dimethacrylate, tetraethylene glycol diacrylate, tetraethylene glycol dimethacrylate, and 1,6-hexane. Diol diacrylate, 1,6-hexanediol dimethacrylate, 1,9-nonanediol diacrylate, 1,9-nonanediol dimethacrylate, bisphenoxyethanol full orange acrylate, bisphenoxyethanol full orange methacrylate, etc. As a commercial item, for example, Aronix M-210, M-240, M-6200 (manufactured by Toa Gosei Co., Ltd.), AYARAD HDDA, HX-220, R-604 (manufactured by Nippon Kayaku Co., Ltd.), Biscoat 260, 312, 335HP (manufactured by Osaka Organic Chemical Industry Co., Ltd.), Light acrylate 1,9-NDA (Kyoeisha) For example).

  Furthermore, commercially available products of polyfunctional urethane acrylates having 9 or more functional groups include, for example, New Frontier R-1150 (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), KAYARAD DPHA-40H (manufactured by Nippon Kayaku Co., Ltd.). ) And the like.

Among these (b2) monofunctional or bifunctional (meth) acrylic acid esters constituting other ethylenically unsaturated compounds, ω-carboxy-polycaprolactone monoacrylate, 1,6-hexanediol diacrylate, 1,9-nonanediol diacrylate is preferred.
Monofunctional, bifunctional, or trifunctional or more (meth) acrylic acid urethanes and (meth) acrylic acid esters (excluding the (b1) component) constituting the component (b2) may be used alone or 2 More than one species can be used in combination.

  In the above (B) polymerizable unsaturated compound, the proportion of the component (b1) and the component (b2) is such that the component (b1) is 15 to 98% by weight, preferably 20 to 95% by weight, and the component (b2) is 85 to 2% by weight, preferably 80 to 5% by weight (where (b1) + (b2) = 100% by weight). When the component (b1) is less than 15% by weight, the developability is deteriorated.

  In the radiation sensitive resin composition of the present invention, the amount of the (B) polymerizable unsaturated compound used is preferably 1 to 250 parts by weight, more preferably 50 to 100 parts by weight with respect to 100 parts by weight of the (A) copolymer. 200 parts by weight. In this case, if the amount of the (B) polymerizable unsaturated compound used is less than 1 part by weight, there may be a residual image during development, whereas if it exceeds 250 parts by weight, the adhesion of the resulting spacer tends to decrease. There is.

  (C) The radiation-sensitive polymerization initiator is a component that generates active species capable of initiating polymerization of a polymerizable unsaturated compound by exposure to radiation such as visible light, ultraviolet light, far ultraviolet light, charged particle beam, and X-ray. Become. As such a radiation sensitive polymerization initiator, for example, 9. H. A carbazole-based O-acyloxime polymerization initiator (hereinafter referred to as “O-acyloxime polymerization initiator (I)”) is preferable.

  Examples of the O-acyloxime polymerization initiator (I) include 1- [9-ethyl-6-benzoyl-9. H. -Carbazol-3-yl] -nonane-1,2-nonane-2-oxime-O-benzoate, 1- [9-ethyl-6-benzoyl-9. H. -Carbazol-3-yl] -nonane-1,2-nonane-2-oxime-O-acetate, 1- [9-ethyl-6-benzoyl-9. H. -Carbazol-3-yl] -pentane-1,2-pentane-2-oxime-O-acetate, 1- [9-ethyl-6-benzoyl-9. H. -Carbazol-3-yl] -octane-1-one oxime-O-acetate, 1- [9-ethyl-6- (2-methylbenzoyl) -9. H. -Carbazol-3-yl] -ethane-1-one oxime-O-benzoate, 1- [9-ethyl-6- (2-methylbenzoyl) -9. H. -Carbazol-3-yl] -ethane-1-one oxime-O-acetate, 1- [9-ethyl-6- (1,3,5-trimethylbenzoyl) -9. H. -Carbazol-3-yl] -ethane-1-one oxime-O-benzoate, 1- [9-butyl-6- (2-ethylbenzoyl) -9. H. -Carbazol-3-yl] -ethane-1-one oxime-O-benzoate.

Of these O-acyloxime type polymerization initiators (I), 1- [9-ethyl-6- (2-methylbenzoyl) -9. H. -Carbazol-3-yl] -ethane-1-one oxime-O-acetate is preferred.
The O-acyloxime type polymerization initiator (I) can be used alone or in admixture of two or more.

In the present invention, as the radiation-sensitive polymerization initiator, an O-acyl oxime photopolymerization initiator other than the O-acyl oxime polymerization initiator (I) (hereinafter referred to as “O-acyl oxime polymerization initiator ( II) ")) can be used in combination.
Examples of the O-acyloxime type polymerization initiator (II) include 1,2-octadion-1- [4- (phenylthio) phenyl] -2- (O-benzoyloxime), 1,2-butanedione-1- [4- (phenylthio) phenyl] -2- (O-benzoyloxime), 1,2-butanedione-1- [4- (phenylthio) phenyl] -2- (O-acetyloxime), 1,2-octadione- 1- [4- (methylthio) phenyl] -2- (O-benzoyloxime), 1,2-octadion-1- [4- (phenylthio) phenyl] -2- (O- (4-methylbenzoyloxime)) And so on.
Of these O-acyloxime type polymerization initiators (II), 1,2-octadion-1- [4- (phenylthio) phenyl] -2- (O-benzoyloxime) is particularly preferable.

In the present invention, the O-acyl oxime type polymerization initiator (I) or a mixture thereof and an O-acyl oxime type polymerization initiator (II) (hereinafter, these are collectively referred to as “O-acyl oxime type polymerization initiator”). )), It is possible to achieve a pacer having good sensitivity and good adhesion to the substrate even with an exposure amount of 1,500 J / m ² or less.

In the radiation sensitive resin composition of the present invention, the amount of the O-acyloxime type polymerization initiator used is preferably 0.1 to 30 parts by weight with respect to 100 parts by weight of the (B) polymerizable unsaturated compound. Preferably it is 1-20 weight part. In this case, if the amount of the O-acyloxime polymerization initiator used is less than 0.1 parts by weight, the residual film ratio tends to decrease during development. There is a tendency for solubility in an alkali developer to decrease.
The proportion of the O-acyloxime polymerization initiator (II) used is 100 parts by weight in total of the O-acyloxime polymerization initiator (I) and the O-acyloxime polymerization initiator (II). , Preferably 30 parts by weight or less, more preferably 20 parts by weight or less.

Furthermore, in the radiation sensitive resin composition of the present invention, one or more other radiation sensitive polymerization initiators can be used in combination with the O-acyloxime type polymerization initiator.
Examples of the other radiation-sensitive polymerization initiator include, for example, acetophenone compounds, biimidazole compounds, benzoin compounds, benzophenone compounds, α-diketone compounds, polynuclear quinone compounds, xanthone compounds, phosphine compounds, Examples include triazine compounds, among which acetophenone compounds and biimidazole compounds are preferable.

Examples of the acetophenone compounds include α-hydroxy ketone compounds and α-amino ketone compounds.
Examples of the α-hydroxyketone compound include 1-phenyl-2-hydroxy-2-methylpropan-1-one and 1- (4-i-propylphenyl) -2-hydroxy-2-methylpropane-1. -One, 4- (2-hydroxyethoxy) phenyl- (2-hydroxy-2-propyl) ketone, 1-hydroxycyclohexylphenylketone and the like. Examples of the α-aminoketone compound include 2 -Methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one, 2- (4- Mention of methylbenzoyl) -2- (dimethylamino) -1- (4-morpholinophenyl) -butan-1-one Examples of compounds other than these include 2,2-dimethoxyacetophenone, 2,2-diethoxyacetophenone, and 2,2-dimethoxy-2-phenylacetophenone.

Among these acetophenone compounds, in particular, 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one, 2- (4-methylbenzoyl) -2- (dimethylamino) -1- (4-Morpholinophenyl) -butan-1-one is preferred.
In the present invention, by using an acetophenone compound in combination, the sensitivity, the shape of the obtained spacer and the compressive strength can be further improved.

  Examples of the biimidazole compound include 2,2′-bis (2-chlorophenyl) -4,4 ′, 5,5′-tetrakis (4-ethoxycarbonylphenyl) -1,2′-biimidazole. 2,2′-bis (2-bromophenyl) -4,4 ′, 5,5′-tetrakis (4-ethoxycarbonylphenyl) -1,2′-biimidazole, 2,2′-bis (2- Chlorophenyl) -4,4 ′, 5,5′-tetraphenyl-1,2′-biimidazole, 2,2′-bis (2,4-dichlorophenyl) -4,4 ′, 5,5′-tetraphenyl -1,2'-biimidazole, 2,2'-bis (2,4,6-trichlorophenyl) -4,4 ', 5,5'-tetraphenyl-1,2'-biimidazole, 2,2 '-Bis (2-bromophenyl)- , 4 ′, 5,5′-tetraphenyl-1,2′-biimidazole, 2,2′-bis (2,4-dibromophenyl) -4,4 ′, 5,5′-tetraphenyl-1, Examples include 2'-biimidazole, 2,2'-bis (2,4,6-tribromophenyl) -4,4 ', 5,5'-tetraphenyl-1,2'-biimidazole, and the like. .

Among these biimidazole compounds, 2,2′-bis (2-chlorophenyl) -4,4 ′, 5,5′-tetraphenyl-1,2′-biimidazole, 2,2′-bis (2 , 4-dichlorophenyl) -4,4 ′, 5,5′-tetraphenyl-1,2′-biimidazole, 2,2′-bis (2,4,6-trichlorophenyl) -4,4 ′, 5 , 5′-tetraphenyl-1,2′-biimidazole and the like are preferable, and 2,2′-bis (2,4-dichlorophenyl) -4,4 ′, 5,5′-tetraphenyl-1,2 ′ is particularly preferable. -Biimidazole is preferred.
In the present invention, by using a biimidazole compound in combination, it is possible to further improve sensitivity, resolution, and adhesion of the resulting spacer to the substrate.

When a biimidazole compound is used in combination, an aliphatic or aromatic compound having a dialkylamino group (hereinafter referred to as “amino sensitizer”) may be added to sensitize it. it can.
Examples of amino sensitizers include N-methyldiethanolamine, 4,4′-bis (dimethylamino) benzophenone, 4,4′-bis (diethylamino) benzophenone, ethyl p-dimethylaminobenzoate, p-dimethylamino. Examples include i-amyl benzoate.
Of these amino sensitizers, 4,4′-bis (diethylamino) benzophenone is particularly preferable.
The amino sensitizers can be used alone or in admixture of two or more.

  Further, when a biimidazole compound and an amino sensitizer are used in combination, a thiol compound can be added as a hydrogen donor compound. The biimidazole compound is sensitized and cleaved by the amino sensitizer to generate an imidazole radical, but as it is, high polymerization initiation ability is not expressed, and the resulting spacer is not preferable such as a reverse taper shape. Often has a shape. However, by adding a thiol compound to a system in which a biimidazole compound and an amino sensitizer coexist, hydrogen radicals are donated from the thiol compound to the imidazole radical, so that the imidazole radical is neutral imidazole. And a component having a sulfur radical having a high polymerization initiating ability is generated, whereby the spacer shape can be made a more preferable forward tapered shape.

Examples of the thiol compound include aromatics such as 2-mercaptobenzothiazole, 2-mercaptobenzoxazole, 2-mercaptobenzimidazole, 2-mercapto-5-methoxybenzothiazole, 2-mercapto-5-methoxybenzimidazole. Compounds: aliphatic monothiols such as 3-mercaptopropionic acid, methyl 3-mercaptopropionate, ethyl 3-mercaptopropionate, octyl 3-mercaptopropionate; 3,6-dioxa-1,8-octanedithiol And bifunctional or higher aliphatic thiols such as pentaerythritol tetra (mercaptoacetate) and pentaerythritol tetra (3-mercaptopropionate).
Of these thiol compounds, 2-mercaptobenzothiazole is particularly preferable.

  In the radiation-sensitive resin composition of the present invention, the use ratio of the other radiation-sensitive polymerization initiator is preferably 100 parts by weight or less, more preferably 80 parts by weight with respect to 100 parts by weight of the total radiation-sensitive polymerization initiator. Part or less, particularly preferably 60 parts by weight or less. In this case, if the use ratio of the other radiation-sensitive polymerization initiator exceeds 100 parts by weight, the intended effect of the present invention may be impaired.

  Further, when the biimidazole compound and the amino sensitizer are used in combination, the addition amount of the amino sensitizer is preferably 0.1 to 50 parts by weight with respect to 100 parts by weight of the biimidazole compound. Preferably it is 1-20 weight part. In this case, if the addition amount of the amino sensitizer is less than 0.1 parts by weight, the effect of improving the sensitivity, resolution and adhesion of the resulting spacer to the substrate tends to be reduced, whereas if it exceeds 50 parts by weight. The spacer shape may be damaged.

  In addition, when a biimidazole compound and an amino sensitizer are used in combination, the addition amount of the thiol compound is preferably 0.1 to 50 parts by weight, more preferably 100 parts by weight of the biimidazole compound. 1 to 20 parts by weight. In this case, if the addition amount of the thiol compound is less than 0.1 parts by weight, the effect of improving the spacer shape tends to be reduced or the film tends to be reduced. On the other hand, if it exceeds 50 parts by weight, the spacer shape is impaired. There is a risk of being. However, in this invention, only radiation sensitive polymerization initiators other than O-acyl oxime type polymerization initiator (I) can be used individually or in mixture of 2 or more types.

-Additives-
In the radiation sensitive resin composition, additives other than the above-mentioned components can be blended as necessary within a range not impairing the intended effect of the present invention.
For example, in order to improve applicability, a surfactant can be blended. As the surfactant, a fluorine-based surfactant and a silicone-based surfactant can be suitably used.
As the fluorosurfactant, a compound having a fluoroalkyl or fluoroalkylene group in at least one of the terminal, main chain and side chain can be suitably used. Specific examples thereof include 1,1,2 , 2-tetrafluorooctyl (1,1,2,2-tetrafluoropropyl) ether, 1,1,2,2-tetrafluorooctyl hexyl ether, octaethylene glycol di (1,1,2,2-tetrafluoro) Butyl) ether, hexaethylene glycol (1,1,2,2,3,3-hexafluoropentyl) ether, octapropylene glycol di (1,1,2,2-tetrafluorobutyl) ether, hexapropylene glycol di ( 1,1,2,2,3,3-hexafluoropentyl) ether, sodium perfluorododecyl sulfonate, 1,1,2,2,8,8,9,9,1 , 10-decafluorododecane, 1,1,2,2,3,3-hexafluorodecane, sodium fluoroalkylbenzenesulfonate, sodium fluoroalkylphosphonate, sodium fluoroalkylcarboxylate, fluoroalkylpolyoxyethylene ether, diglycerin Examples thereof include tetrakis (fluoroalkyl polyoxyethylene ether), fluoroalkyl ammonium iodide, fluoroalkyl betaine, fluoroalkyl polyoxyethylene ether, perfluoroalkyl polyoxyethanol, perfluoroalkyl alkoxylate, and fluorine-based alkyl ester. .

Examples of these commercially available products include BM-1000, BM-1100 (manufactured by BM CHEMIE), MegaFuck F142D, F172, F173, F183, F178, F191, F191, F471, and F476. (Above, manufactured by Dainippon Ink & Chemicals, Inc.), Florard FC 170C, FC-171, FC-430, FC-431 (above, manufactured by Sumitomo 3M), Surflon S-112, S-113, S-131, S-141, S-145, S-382, SC-101, SC-102, SC-103, SC-104, SC-105, SC-106 ( Asahi Glass Co., Ltd.), Ftop EF301, 303, 352 (above, Shin-Akita Kasei Co., Ltd.), Footent FT-100, FT-11 FT-140A, FT-150, FT-250, FT-251, FTX-251, FTX-218, FT-300, FT-310, FT-400S ) Made by Neos).
Examples of the silicone-based surfactant include Torre Silicone DC3PA, DC7PA, SH11PA, SH21PA, SH28PA, SH29PA, SH30PA, SH-190, SH-193, SZ-6032, SF -8428, DC-57, DC-190 (above, manufactured by Toray Dow Corning Silicone Co., Ltd.), TSF-4440, TSF-4300, TSF-4445, TSF-4446, TSF-4460, TSF-4442 (The above-mentioned, GE Toshiba Silicone Co., Ltd. product) etc. can be mentioned what is marketed.

  Furthermore, as surfactants other than the above, for example, polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether; polyoxyethylene n-octylphenyl ether, polyoxy Polyoxyethylene aryl ethers such as ethylene n-nonylphenyl ether; nonionic surfactants such as polyoxyethylene dialkyl esters such as polyoxyethylene dilaurate and polyoxyethylene distearate, and commercially available products such as KP341 (Shin-Etsu) Chemical Industry Co., Ltd.), Polyflow No. 57, 95 (manufactured by Kyoeisha Yushi Chemical Co., Ltd.).

These surfactants can be used alone or in admixture of two or more.
The compounding amount of the surfactant is preferably 5 parts by weight or less, more preferably 2 parts by weight or less with respect to 100 parts by weight of the copolymer (A). In this case, when the compounding amount of the surfactant exceeds 5 parts by weight, there is a tendency that film roughening is likely to occur during coating.

Moreover, in order to further improve the adhesion to the substrate, an adhesion assistant can be blended.
As the adhesion aid, a functional silane coupling agent is preferable, and examples thereof include a silane coupling agent having a reactive functional group such as a carboxyl group, a methacryloyl group, an isocyanate group, and an epoxy group. More specifically, trimethoxysilylbenzoic acid, γ-methacryloyloxypropyltrimethoxysilane, vinyltriacetoxysilane, vinyltrimethoxysilane, γ-isocyanatopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane and the like can be mentioned.
These adhesion assistants can be used alone or in admixture of two or more.
The blending amount of the adhesion assistant is preferably 20 parts by weight or less, more preferably 10 parts by weight or less with respect to 100 parts by weight of the copolymer (A). In this case, when the blending amount of the adhesion assistant exceeds 20 parts by weight, there is a tendency that a development residue is likely to occur.

  In addition, other additives can be added for the purpose of improving storage stability. Specific examples include sulfur, quinones, hydroquinones, polyoxy compounds, amines, and nitronitroso compounds. Examples thereof include 4-methoxyphenol and N-nitroso-N-phenylhydroxylamine aluminum. These are preferably used in an amount of 3.0 parts by weight or less, more preferably 0.001 to 0.5 parts by weight with respect to 100 parts by weight of the copolymer (A). When the amount exceeds 3.0 parts by weight, sufficient sensitivity cannot be obtained, and the pattern shape deteriorates.

In order to improve heat resistance, an N- (alkoxymethyl) glycoluril compound, an N- (alkoxymethyl) melamine compound, and a compound having a bifunctional or higher functional epoxy group in one molecule can be added. Specific examples of the N- (alkoxymethyl) glycoluril compound include N, N, N, N-tetra (methoxymethyl) glycoluril, N, N, N, N-tetra (ethoxymethyl) glycoluril, N, N, N, N-tetra (n-propoxymethyl) glycoluril, N, N, N, N-tetra (i-propoxymethyl) glycoluril, N, N, N, N-tetra (n-butoxymethyl) glycol Examples include uril, N, N, N, N-tetra (t-butoxymethyl) glycoluril and the like. Of these, N, N, N, N-tetra (methoxymethyl) glycoluril is particularly preferable. Specific examples of the N- (alkoxymethyl) melamine compound include N, N, N, N, N, N-hexa (methoxymethyl) melamine, N, N, N, N, N, N-hexa (ethoxymethyl). ) Melamine, N, N, N, N, N, N-hexa (n-propoxymethyl) melamine, N, N, N, N, N, N-hexa (i-propoxymethyl) melamine, N, N, N , N, N, N-hexa (n-butoxymethyl) melamine, N, N, N, N, N, N-hexa (t-butoxymethyl) melamine and the like. Of these, N, N, N, N, N, N-hexa (methoxymethyl) melamine is particularly preferable. Examples of these commercially available products include Nicalac N-2702 and MW-30M (manufactured by Sanwa Chemical Co., Ltd.).
Examples of compounds having two or more functional epoxy groups in one molecule include ethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, and polypropylene glycol diglycidyl. Ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerin diglycidyl ether, trimethylolpropane triglycidyl ether, hydrogenated bisphenol A diglycidyl ether, bisphenol A diglycidyl ether, phenol novolac type liquid epoxy Resin etc. are mentioned. Specific examples of these commercially available products include Epolite 40E, Epolite 100E, Epolite 200E, Epolite 70P, Epolite 200P, Epolite 400P, Epolite 40E, Epolite 1500NP, Epolite 1600, Epolite 80MF, Epolite 100MF, Epolite 4000, Epolite 3002 (and more) Chemical Co., Ltd.), Epicoat 152, Epicoat 154 (above Japan Epoxy Resin Co., Ltd.) and the like. These can be used alone or in combination of two or more.

The composition solution radiation-sensitive resin composition is usually prepared by dissolving components such as (A) a copolymer, (B) a polymerizable compound, and (C) a photopolymerization initiator in an appropriate solvent. It is prepared as a composition solution.
As the solvent used for the preparation of the composition solution, a solvent that uniformly dissolves each component constituting the radiation-sensitive resin composition and does not react with each component is used.
As such a solvent, the thing similar to what was illustrated as a solvent which can be used in order to manufacture the above-mentioned (A) copolymer can be mentioned.

  Of these solvents, alcohols, glycol ethers, ethylene glycol alkyl ether acetates, esters and diethylene glycol are preferably used from the viewpoints of solubility of each component, reactivity with each component, and ease of film formation. It is done. Among these, for example, benzyl alcohol, 2-phenylethyl alcohol, 3-phenyl-1-propanol, ethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol diethyl ether, diethylene glycol ethyl methyl ether, diethylene glycol dimethyl ether, propylene glycol monomethyl ether Propylene glycol monomethyl ether acetate, methyl methoxypropionate, ethyl ethoxypropionate, 3-methoxybutyl acetate and the like can be particularly preferably used.

Furthermore, in order to improve the in-plane uniformity of the film thickness together with the above solvent, a high boiling point solvent can be used in combination. Examples of the high boiling point solvent that can be used in combination include N-methylformamide, N, N-dimethylformamide, N-methylformanilide, N-methylacetamide, N, N-dimethylacetamide, N-methylpyrrolidone, dimethylsulfoxide, and benzylethyl ether. , Dihexyl ether, acetonyl acetone, isophorone, caproic acid, caprylic acid, 1-octanol, 1-nonanol, benzyl acetate, ethyl benzoate, diethyl oxalate, diethyl maleate, γ-butyrolactone, ethylene carbonate, propylene carbonate, phenyl Examples include cellosolve acetate. Of these, N-methylpyrrolidone, γ-butyrolactone, and N, N-dimethylacetamide are preferable.
In addition, the usage-amount of the solvent in the radiation sensitive resin composition of this invention is the quantity by which solid content concentration of this composition is 10-50 weight% normally, Preferably it is 15-40 weight%.
The composition solution prepared in this way can be used for use after filtration through a Millipore filter having a pore size of, for example, about 0.2 to 0.5 μm, if necessary.

  The radiation sensitive resin composition is particularly suitable as a material for forming a spacer for a display panel such as a liquid crystal panel or a touch panel.

Spacer for display panel The present invention can form the spacer for liquid crystal display panel of the present invention by including at least the following steps in the following order.
(A) A step of forming a film of the radiation sensitive resin composition of the present invention on a substrate.
(B) A step of exposing at least a part of the coating.
(C) A step of developing the film after exposure.
(D) A step of heating the coated film after development.

Step (a) In step (a), the composition solution is applied to the surface of the substrate and then pre-baked to remove the solvent, thereby forming a coating film.
As a method of forming a film of the radiation sensitive resin composition of the present invention, for example, (1) a coating method and (2) a dry film method can be used.
As a coating method of the composition solution, for example, an appropriate method such as a spray method, a roll coating method, a spin coating method (spin coating method), a slit die coating method, a bar coating method, or an ink jet coating method can be employed. In particular, a spin coating method and a slit die coating method are preferable.
Further, when the film of the radiation sensitive resin composition of the present invention is formed, when (2) the dry film method is employed, the dry film is formed on a base film, preferably a flexible base film. It is obtained by laminating a radiation sensitive layer comprising the radiation sensitive resin composition of the invention (hereinafter referred to as “radiation sensitive dry film”).

The radiation-sensitive dry film can be formed by laminating a radiation-sensitive layer on the base film by applying the radiation-sensitive resin composition of the present invention, preferably as a liquid composition, and then drying. . As the base film of the radiation-sensitive dry film, for example, a synthetic resin film such as polyethylene terephthalate (PET), polyethylene, polypropylene, polycarbonate, polyvinyl chloride, or the like can be used. The thickness of the base film is suitably in the range of 15 to 125 μm. The thickness of the resulting radiation sensitive layer is preferably about 1 to 30 μm.
Further, when the radiation-sensitive dry film is not used, a cover film can be further laminated on the radiation-sensitive layer and stored. This cover film needs to have an appropriate releasability so that it does not peel off when not in use and can be easily peeled off when in use. As a cover film satisfying such conditions, for example, a film based on a silicone-based release agent or a baking film can be used on the surface of a synthetic resin film such as a PET film, a polypropylene film, a polyethylene film, or a polyvinyl chloride film. . A thickness of about 25 μm is usually sufficient for the cover film.
Moreover, although the conditions of prebaking differ also with the kind of each structural component, a mixture ratio, etc., it is normally about 1 to 15 minutes at 70-90 degreeC.

(B) Step Next, the pre-baked coating film is exposed to polymerization through a mask having a predetermined pattern and polymerized.
Visible light, ultraviolet rays, far ultraviolet rays, charged particle beams, X-rays, and the like can be appropriately selected as radiation used for exposure, but radiation having a wavelength in the range of 190 to 450 nm is preferable.
The exposure dose is usually 100 to 10,000 J / m ² , preferably 1, as the value of the intensity of the exposed radiation at a wavelength of 365 nm measured by an illuminometer (OAI model 356, manufactured by OAI Optical Associates Inc.). 500 to 4,000 J / m ² .

(C) Process After exposure, it develops with a developing solution, an unnecessary part is removed, and a pattern is formed.
As the developing method, for example, any of a liquid filling method, a dipping method, a shower method and the like may be used, and the developing time is usually 30 to 180 seconds.
Examples of the developer include inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, and ammonia; primary amines such as ethylamine and n-propylamine; Secondary amines such as n-propylamine; tertiary amines such as trimethylamine, methyldiethylamine, ethyldimethylamine, triethylamine; tertiary alkanolamines such as dimethylethanolamine, methyldiethanolamine, triethanolamine; pyrrole, piperidine , N-methylpiperidine, N-methylpyrrolidine, 1,8-diazabicyclo [5.4.0] -7-undecene, 1,5-diazabicyclo [4.3.0] -5-nonene 3 Secondary amines; pyridine, It can be used tetramethylammonium hydroxide, the aqueous solution of an alkaline compound such as quaternary ammonium salts such as tetraethylammonium hydroxide; lysine, lutidine, aromatic tertiary amines such as quinoline.
In addition, an appropriate amount of a water-soluble organic solvent such as methanol or ethanol and / or a surfactant can be added to the aqueous solution of the alkaline compound.
After development, for example, by washing with running water, for example, for 30 to 90 seconds, unnecessary portions are removed, and then compressed air or compressed nitrogen is blown to dry to form a predetermined pattern.

(D) Process The film after development is heated. That is, after development, this pattern is applied to a predetermined temperature, for example, 150 to 250 ° C., for a predetermined time by a heating device such as a hot plate or oven, for example, for 5 to 30 minutes on the hot plate, for example, 30 to 90 minutes in the oven. The target spacer can be obtained by heat treatment.

Liquid crystal display panel The liquid crystal display panel of the present invention is produced by the following method. First, two substrates on which a protective film having a liquid crystal alignment ability is formed are prepared, and the two substrates are placed through a gap (cell gap) so that the liquid crystal alignment directions in the respective protective films are orthogonal or antiparallel. The peripheral portions of the two substrates are bonded together via the spacer of the present invention, the liquid crystal is filled in the cell gap defined by the surface of the substrate and the spacer, the filling hole is sealed, and the liquid crystal cell is Constitute. Then, on the outer surface of the liquid crystal cell, that is, on the other surface side of each substrate constituting the liquid crystal cell, a polarizing plate is aligned or orthogonal to the liquid crystal alignment direction of the protective film formed on one surface of the substrate. Thus, the liquid crystal display panel of the present invention is obtained.

  Examples of the liquid crystal include a nematic liquid crystal and a smectic liquid crystal. Among them, nematic liquid crystal is preferable, for example, Schiff base liquid crystal, azoxy liquid crystal, biphenyl liquid crystal, phenyl cyclohexane liquid crystal, ester liquid crystal, terphenyl liquid crystal, biphenyl cyclohexane liquid crystal, pyrimidine liquid crystal, dioxane liquid crystal, bicyclooctane. Type liquid crystal, cubane type liquid crystal, etc. are used. Further, for these liquid crystals, for example, cholesteric liquid crystals such as cholestyl chloride, cholesteryl nonate, cholesteryl carbonate, and chiral agents such as those sold under the trade names “C-15” and “CB-15” (manufactured by Merck). Etc. can also be used. Furthermore, a ferroelectric liquid crystal such as p-decyloxybenzylidene-p-amino-2-methylbutylcinnamate can also be used.

  In addition, the polarizing plate used outside the liquid crystal cell is composed of a polarizing plate in which a polarizing film called an H film that has absorbed iodine while sandwiching and stretching polyvinyl alcohol is sandwiched between cellulose acetate protective films, or the H film itself. A polarizing plate etc. can be mentioned.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. However, the present invention is not limited to these examples.
Synthesis example 1
A flask equipped with a condenser and a stirrer was charged with 4 parts by weight of 2,2′-azobisisobutyronitrile and 220 parts by weight of diethylene glycol methyl ethyl ether. Subsequently, 5 parts by weight of styrene, 10 parts by weight of methacrylic acid, 4 parts by weight of acrylic acid, 31 parts by weight of benzyl methacrylate, and 45 parts by weight of n-butyl methacrylate were substituted with nitrogen and then further 1,3-butadiene. 5 parts by weight were charged and the temperature of the solution was raised to 80 ° C. while gently stirring, and this temperature was maintained for 4 hours, and further maintained at 100 ° C. for 1 hour, and the copolymer [A-1] was contained. A polymer solution was obtained. The obtained polymer solution had a solid content concentration of 31.0% by weight, and the polymer had a weight average molecular weight of 12,000 (weight average molecular weight was GPC (gel permeation chromatography) HLC-8020. (Molecular weight in terms of polystyrene measured using Tosoh Corporation).

Synthesis example 2
A flask equipped with a condenser and a stirrer was charged with 4 parts by weight of 2,2′-azobisisobutyronitrile and 220 parts by weight of propylene glycol monomethyl ether acetate. Subsequently, 5 parts by weight of styrene, 10 parts by weight of methacrylic acid, 4 parts by weight of acrylic acid, 31 parts by weight of benzyl methacrylate, and 45 parts by weight of n-butyl methacrylate were substituted with nitrogen and then further 1,3-butadiene. 5 parts by weight were charged and the temperature of the solution was raised to 80 ° C. while gently stirring, and this temperature was maintained for 4 hours, and further maintained at 100 ° C. for 1 hour, and the copolymer [A-2] was contained. A polymer solution was obtained. The obtained polymer solution had a solid content concentration of 31.0% by weight, and the polymer had a weight average molecular weight of 12,000 (weight average molecular weight was GPC (gel permeation chromatography) HLC-8020. (Molecular weight in terms of polystyrene measured using Tosoh Corporation).

Synthesis example 3
A flask equipped with a condenser and a stirrer was charged with 4 parts by weight of 2,2′-azobisisobutyronitrile and 220 parts by weight of diethylene glycol methyl ethyl ether. Subsequently, 5 parts by weight of styrene, 10 parts by weight of methacrylic acid, 4 parts by weight of acrylic acid, 31 parts by weight of benzyl methacrylate, and 50 parts by weight of n-butyl methacrylate were substituted with nitrogen, and then gently stirred. The temperature of the solution was raised to 80 ° C., this temperature was maintained for 4 hours, and further maintained at 100 ° C. for 1 hour to obtain a polymer solution containing the copolymer [A-3]. The resulting polymer solution had a solid content concentration of 32.0% by weight, and the polymer had a weight average molecular weight of 15,000 (weight average molecular weight was GPC (gel permeation chromatography) HLC-8020. (Molecular weight in terms of polystyrene measured using Tosoh Corporation).

Synthesis example 4
A flask equipped with a condenser and a stirrer was charged with 5 parts by weight of 2,2′-azobis (2,4-dimethylvaleronitrile) and 200 parts by weight of diethylene glycol methyl ethyl ether, followed by 18 parts by weight of methacrylic acid, methacrylic acid. After charging 40 parts by weight of glycidyl, 5 parts by weight of styrene, and 32 parts by weight of tricyclo [5.2.1.0 ^2,6 ] decan-8-yl methacrylate, and substituting with nitrogen, 5 parts by weight of 1,3-butadiene is further added. The temperature of the solution was raised to 70 ° C. while stirring gently, and the temperature was maintained for 5 hours for polymerization to obtain a solution of copolymer [A-4]. The resulting polymer solution had a solid content concentration of 33.3% by weight, and the polymer had a weight average molecular weight of 20,000 (weight average molecular weight was GPC (gel permeation chromatography) HLC-8020. (Molecular weight in terms of polystyrene measured using Tosoh Corporation).

Example 1
Preparation of Composition Solution (A) 100 parts by weight (solid content) of the copolymer [A-1] solution obtained in Synthesis Example 1 as a copolymer, (B) KAYARAD DPHA (Nippon Kayaku Co., Ltd.) as a polymerizable compound 100 parts by weight, manufactured by Nippon Kayaku Co., Ltd. 30 parts by weight, (C) 2-methyl-1- [4- (methylthio) phenyl] -2 as a photopolymerization initiator -Morpholinopropan-1-one (Irgacure 907 manufactured by Ciba Specialty Chemicals) 5 parts by weight, 2,2'-bis (2-chlorophenyl) -4,4 ', 5,5'-tetraphenyl-1,2 Use 2.5 parts by weight of '-biimidazole, 2.5 parts by weight of 4,4'-bis (diethylamino) benzophenone, and 1.25 parts by weight of 2-mercaptobenzothiazole so that the solid content concentration becomes 30% by weight. Niechire After dissolving in N-glycol methyl ethyl ether, the solution was filtered through a Millipore filter having a pore size of 0.2 μm to prepare a composition solution (S-1).

(I) Formation of Spacer The above composition solution was applied onto an alkali-free glass substrate using a spinner, and then prebaked on a hot plate at 90 ° C. for 3 minutes to form a coating film having a thickness of 3.5 μm.
The coating film obtained above was exposed to ultraviolet rays with an exposure gap of 200 μm and an exposure intensity of 300 W / m ^{2 at} a wavelength of 365 nm through a mask having a 15 μm round pattern. Subsequently, after developing with a 0.05 wt% potassium hydroxide aqueous solution at 25 ° C. for 120 seconds, rinsing was performed with pure water for 1 minute. Furthermore, it heated at 230 degreeC in oven for 20 minutes, and the spacer was formed.

(II) Observation of the surface state The surface state of the obtained spacer is observed with a scanning electron microscope. When the surface has protrusion-like foreign matters or roughness, the mark is x, and there are no protrusion-like foreign matters or roughness on the surface. The case was marked with ○. The results are shown in Table 2.

(III) Sensitivity Evaluation In the pattern obtained in (I) above, if the sensitivity at which the residual film ratio after development is 90% or more is 1,500 J / m ² or less, it can be said that the sensitivity is good. The results are shown in Table 2.

(IV) Evaluation of rubbing resistance On the substrate obtained in (I) above, AL3046 (manufactured by JSR Co., Ltd.) was applied as a liquid crystal aligning agent by a printing machine for applying a liquid crystal alignment film, and dried at 180 ° C. for 1 hour. A coating film of an orientation agent having a dry film thickness of 0.05 μm was formed.
The coating film was rubbed with a rubbing machine having a roll around which a nylon cloth was wound at a roll rotation speed of 500 rpm and a stage moving speed of 1 cm / sec. Table 2 shows the presence or absence of scraping or peeling of the spacer pattern.

(V) Evaluation of adhesiveness It exposed at 500 J / m < ² > through the mask with the pattern of 8-15 micrometers size, and the presence or absence of the pattern after image development was confirmed. If the mask pattern size is 10 μm or less and there is a pattern, it can be said that the adhesion is good. The results are shown in Table 2.

(VI) Evaluation of elastic recovery rate About the obtained spacer, using a micro-compression tester (trade name DUH-201, manufactured by Shimadzu Corporation), a flat indenter with a diameter of 50 μm was used for both loading speed and unloading speed. A load of up to 50 mN was applied as 2.6 mN / sec, the load was held for 5 seconds, and then unloaded, and a load-deformation curve at load and a load-deformation curve during loading were prepared. At this time, as shown in FIG. 1, the difference between the deformation amount at the load of 50 mN and the deformation amount at the load of 5 mN is L1, and the deformation amount at the load of 50 mN and the deformation amount at the load of 5 mN at unloading. The elastic recovery rate was calculated by the following formula, with the difference between L2 and L2.
Elastic recovery rate (%) = L2 × 100 / L1
Table 2 shows the elastic recovery rate and the amount of mutation.

(VII) Evaluation of stripping solution resistance The substrate on which the spacer was formed was immersed in an alignment layer stripping solution (product name: TS-204, manufactured by Sanyo Chemical Co., Ltd.) at 50 ° C. for 30 minutes, and further changed in film thickness after heating at 210 ° C. for 15 minutes. Was measured. Evaluation was carried out by film thickness after heating × 100 / initial film thickness. If there is no change in the film thickness before and after immersion in the alignment film stripping solution, it can be said that the alignment film stripping solution resistance is good. The results are shown in Table 2.

Examples 2-24, Comparative Examples 1-6
In Example 1, a composition solution was prepared and a spacer was formed in the same manner as in Example 1, except that the types and amounts described in Table 1 were used as the components (A) to (C). And evaluated. The addition amount of (B) to (C) is a weight ratio with respect to 100 parts by weight of (A) copolymer.
As is clear from Tables 1 and 2, Examples 1 to 24 are the radiation-sensitive resin compositions of the present invention, and all have sufficient spacer shapes and film thicknesses with an exposure amount of 1,500 J / m ² or less. It is possible to form a display panel spacer that has high flexibility by compressive load, is excellent in adhesion, rubbing resistance, heat resistance, etc., and has excellent stripping liquid resistance.
On the other hand, in Comparative Example 1, when the component (b-1) is used alone, a sufficient spacer cannot be formed with an exposure amount of 1,500 J / m ² or less. Comparative Examples 2 and 3 are cases where the component (b-2) is used alone, and there are protrusion-like foreign matters and roughness on the surface of the spacer, the rubbing resistance is low, and the peeling liquid resistance is also low. Comparative Example 4 is a case where the component (b-1) and the component (b-2) are used at the same time, but the case where the component (b-1) is 10% by weight and the component (b-2) is 90% by weight. There are protrusion-like foreign matters and roughness on the surface of the spacer, the rubbing resistance is low, and the peeling liquid resistance is also low.

In Table 1, the abbreviations of the components indicate the following compounds.
(B-1): KAYARAD DPHA (manufactured by Nippon Kayaku Co., Ltd.)
(B-2): KAYARAD UX-2201 (manufactured by Nippon Kayaku Co., Ltd.)
(B-3): KAYARAD UX-3204 (manufactured by Nippon Kayaku Co., Ltd.)
(B-4): KAYARAD UX-0937 (manufactured by Nippon Kayaku Co., Ltd.)
(B-5): KAYARAD DPHA-40H (manufactured by Nippon Kayaku Co., Ltd.)
(B-6): Aronix TO-1382 (manufactured by Toa Gosei Co., Ltd.)
(B-7): Light acrylate 1,9-NDA (manufactured by Kyoeisha)
(B-8): Aronix M-5300 (above, manufactured by Toa Gosei Co., Ltd.)

(C-1): 1- [9-ethyl-6- (2-methylbenzoyl) -9.H.-carbazol-3-yl] -ethane-1-one oxime-O-acetate (Ciba Specialty Chemicals) CGI-242)
(C-2): 1,2-octadion-1- [4- (phenylthio) phenyl] -2- (O-benzoyloxime) (CGI-124 manufactured by Ciba Specialty Chemicals)
(C-3): 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one (Irgacure 907 manufactured by Ciba Specialty Chemicals)
(C-4): 2- (4-methylbenzoyl) -2- (dimethylamino) -1- (4-morpholinophenyl) -butan-1-one (Irgacure 379 manufactured by Ciba Specialty Chemicals)
(C-5): 2,2′-bis (2-chlorophenyl) -4,4 ′, 5,5′-tetraphenyl-1,2′-biimidazole (C-6): 4,4′-bis (Diethylamino) benzophenone (C-7): 2-mercaptobenzothiazole (D-1): phenol novolac epoxy resin Epicoat 152 (manufactured by Japan Epoxy Resin Co., Ltd.)
(D-2): N- (alkoxymethyl) melamine compound Nicalac MW-30M (manufactured by Sanwa Chemical Co., Ltd.)
In Table 1,-indicates that the component is not added.
The evaluation results are shown in Table 2.

It is a figure which illustrates the load-deformation amount curve at the time of the load in evaluation of an elastic recovery factor, and a slow load.

Claims (13)

(A) a copolymer of (a1) an ethylenically unsaturated carboxylic acid and / or an ethylenically unsaturated carboxylic acid anhydride and (a2) another ethylenically unsaturated compound,
(B) (b1) a trifunctional or higher-functional (meth) acrylic acid ester and (b2) a polymerizable compound mainly comprising another ethylenically unsaturated compound other than (b1), and (C) radiation sensitivity. A radiation-sensitive resin composition comprising a polymerization initiator.   (A) In the copolymer, the repeating unit derived from (a1) is 5 to 50% by weight, the repeating unit derived from (a2) is 95 to 50% by weight [where (a1) + (a2) = 100% %]. The radiation-sensitive resin composition according to claim 1.   (B) The radiation-sensitive resin composition according to claim 1 or 2, wherein (b1) a trifunctional or higher functional (meth) acrylic acid ester is dipentaerythritol hexaacrylate.   (B) In the polymerizable compound, (b2) the other ethylenically unsaturated compound is (α) a polyfunctional isocyanate compound, (β) a (meth) acrylate compound containing one hydroxyl group in the molecule, ( The radiation-sensitive resin composition according to any one of claims 1 to 3, which is a polyfunctional urethane acrylate having a weight average molecular weight of 15,000 or less obtained by reacting γ) polyol.   In the polyfunctional urethane acrylate, the ratio of (α) polyfunctional isocyanate compound, (β) (meth) acrylate compound containing one hydroxyl group in the molecule, and (γ) polyol is (α) isocyanate group and (β 5. The radiation sensitive resin according to claim 4, wherein the molar ratio of the hydroxyl group of () to the hydroxyl group of (γ) is in the range of 1.00 / 1.00 / 0.50 to 1.00 / 1.20 / 0.60. Composition.   (B) In the polymerizable compound, the ratio of the component (b1) to the component (b2) is (b1) 20 to 95% by weight, (b2) 80 to 5% by weight [where (b1) + (b2) = 100 % By weight] The radiation sensitive resin composition according to any one of claims 1 to 5.   The radiation-sensitive resin composition according to any one of claims 1 to 6, wherein the amount of the polymerizable compound (B) used is 1 to 250 parts by weight with respect to 100 parts by weight of the copolymer (A).   (C) In the radiation sensitive polymerization initiator, at least one is an O-acyl oxime type polymerization initiator, The radiation sensitive resin composition in any one of Claims 1-7.   (C) The radiation sensitive polymerization initiator is used in an amount of 0.1 to 30 parts by weight per 100 parts by weight of (B) polymerizable unsaturated compound. Composition.   The radiation sensitive resin composition in any one of Claims 1-9 used for formation of the spacer for liquid crystal display panels.   The spacer for liquid crystal display panels formed from the radiation sensitive resin composition in any one of Claims 1-10. A method for forming a spacer for a liquid crystal display panel, comprising at least the following steps in the order described below.
(A) The process of forming the coating film of the radiation sensitive resin composition in any one of Claims 1-10 on a board | substrate.
(B) A step of exposing at least a part of the coating.
(C) A step of developing the film after exposure.
(D) A step of heating the coated film after development. A liquid crystal display panel comprising the spacer according to claim 11.