JP2005208360A - Radiation-sensitive resin composition for forming spacer, spacer and method for forming the same, and liquid crystal display element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radiation-sensitive resin composition for forming spacers which is of high resolution and of high sensitivity even when radiation for exposure practically contains no beam with wavelength <350 nm, and which easily forms the spacers excellent in various performances such as a pattern shape, compression strength, rubbing resistance, and adhesion to a transparent substrate. <P>SOLUTION: The radiation-sensitive resin composition for the spacers contains [A] a copolymer of an unsaturated carboxylic acid and/or an unsaturated carboxylic acid anhydride (a1), an unsaturated compound containing an epoxy group (a2) and another unsaturated compound (a3), [B] polymerizable unsaturated compound, [C] a biimidazole compound, [D] a radiation-sensitive polymerization initiator having a carbonyl group, and [E] a compound having a dialkylamino group and/or [F] a thiol compound. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a radiation-sensitive resin composition for forming a spacer, a spacer, a method for forming the spacer, and a liquid crystal display device. More specifically, the spacer can be formed even by exposure to radiation that does not substantially contain a wavelength of less than 350 nm. The present invention relates to a spacer-forming radiation-sensitive resin composition, a spacer formed therefrom, a method for forming the spacer, and a liquid crystal display device having the spacer.

Conventionally, liquid crystal display elements have been used spacer particles such as glass beads and plastic beads having a predetermined particle size in order to keep the distance between two transparent substrates constant. Since spacer particles are randomly scattered on a transparent substrate such as a glass substrate, if spacer particles are present in the pixel formation region, the phenomenon of spacer particle reflection will occur, or incident light will be scattered, reducing the contrast of the liquid crystal display element. There was a problem.
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.

  By the way, radiation from a mercury lamp used as a light source in photolithography is usually around 436 nm (g line), around 404 nm (h line), around 365 nm (i line), around 335 nm, around 315 nm (j line), In order to show a strong spectrum around 303 nm, etc., the radiation-sensitive polymerization initiator that is a component of the radiation-sensitive resin composition is selected to have a maximum absorption wavelength in the wavelength region of these strong spectra. Usually, from the viewpoint of transparency, a radiation-sensitive polymerization initiator having a maximum absorption wavelength in the region of i-line or less is used (see, for example, Patent Document 1). . When a radiation-sensitive polymerization initiator having a maximum absorption wavelength near the g-line and h-line whose wavelength is longer than the i-line is used, the radiation-sensitive polymerization initiator has absorption in a wavelength region close to visible light. The contained radiation sensitive resin composition is colored, and the transparency of the formed film is lowered. When the transparency of the film is low, the curing reaction proceeds on the film surface during exposure, and the curing reaction in the depth direction of the film becomes insufficient. As a result, the shape of the spacer obtained after development is a reverse taper (as a cross-sectional shape) The side of the film surface has an inverted triangular shape that is longer than the side of the substrate side), which causes the spacer to peel off during the subsequent rubbing treatment of the alignment film.

JP 2001-261761 A

  On the other hand, in the case of forming a spacer by photolithography on a transparent substrate used for an actual spacer forming process, for example, a color filter, a proximity exposure machine is often used. For improvement, mercury lamps with high illuminance are generally used. In this case, although there is an effect in improving the throughput, in order to reduce the lifetime of the mirror used in the exposure machine as it is, in many cases, radiation with a short wavelength of less than 350 nm having high energy is cut with a filter and used. . However, since most conventional radiation-sensitive polymerization initiators have a maximum absorption wavelength below 350 nm, cutting radiation with a wavelength less than 350 nm is sufficient to provide active species such as radicals necessary for curing the radiation-sensitive resin composition. It cannot occur and the curing reaction becomes insufficient, and it becomes difficult to obtain satisfactory spacer dimensions and shapes.

  The problem of the present invention is that, even when exposed to radiation that does not substantially contain a wavelength of less than 350 nm, it has high resolution and high sensitivity, and has a pattern shape, compressive strength, rubbing resistance, adhesion to a transparent substrate, and the like. It is an object to provide a radiation-sensitive resin composition for spacers capable of easily forming a spacer having excellent performance, a spacer formed therefrom, a method for forming the spacer, and a liquid crystal display device having the spacer.

The present invention, first,
[A] a copolymer of (a1) an unsaturated carboxylic acid and / or an unsaturated carboxylic acid anhydride, (a2) an epoxy group-containing unsaturated compound, and (a3) another unsaturated compound,
[B] polymerizable unsaturated compound,
[C] biimidazole compound,
A radiation-sensitive resin composition for spacer formation, comprising [D] a radiation-sensitive polymerization initiator having a carbonyl group, and [E] a compound having a dialkylamino group and / or [F] a thiol compound. Consists of.
The term “radiation” as used in the present invention means one containing ultraviolet rays, far ultraviolet rays, X-rays, electron beams, molecular beams, γ rays, synchrotron radiation, proton beam rays, and the like.

  Secondly, the present invention comprises a spacer formed from the radiation-sensitive resin composition for forming a spacer.

Thirdly, the present invention comprises a spacer forming method characterized by including at least the following steps (a) to (d).
(A) A step of forming a coating of the radiation-sensitive resin composition for forming a spacer according to claim 1 or 2 on a substrate.
(B) A step of exposing at least a part of the film to radiation that does not substantially contain a wavelength of less than 350 nm.
(C) A step of developing the film after exposure.
(D) A step of heating the film after development.

  Fourthly, the present invention comprises a liquid crystal display element comprising the spacer.

Hereinafter, the present invention will be described in detail.
The following spacer radiation sensitive resin composition, the spacer radiation sensitive resin composition of the present invention (hereinafter, simply referred to as. "Radiation-sensitive resin composition") will be described in detail each component of.
-[A] copolymer-
The component [A] in the radiation-sensitive resin composition of the present invention is (a1) an unsaturated carboxylic acid and / or an unsaturated carboxylic acid anhydride (hereinafter collectively referred to as “compound (a1)”), ( a2) a copolymer of an epoxy group-containing unsaturated compound (hereinafter referred to as “compound (a2)”) and (a3) another unsaturated compound (hereinafter referred to as “compound (a3)”) (hereinafter referred to as “[ A] a copolymer ").

Examples of the compound (a1) include acrylic acid, methacrylic acid, crotonic acid, succinic acid mono (2-acryloyloxyethyl), succinic acid mono (2-methacryloyloxyethyl), hexahydrophthalic acid mono (2- Monocarboxylic acids such as acryloyloxyethyl) and hexahydrophthalic acid mono (2-methacryloyloxyethyl); dicarboxylic acids such as maleic acid, fumaric acid, citraconic acid, mesaconic acid and itaconic acid; and anhydrides of these dicarboxylic acids Examples can be given.
Of these compounds (a1), acrylic acid, methacrylic acid, maleic anhydride and the like are preferable from the viewpoint of copolymerization reactivity and availability.
The said compound (a1) can be used individually or in mixture of 2 or more types.

  [A] In the copolymer, the content of the structural unit derived from the compound (a1) is preferably 5 to 50% by weight, particularly preferably 10 to 40% by weight. In this case, if the content of the structural unit is less than 5% by weight, the compressive strength, heat resistance and chemical resistance of the resulting spacer tend to decrease, while if it exceeds 50% by weight, the radiation sensitive resin The storage stability of the composition may be reduced.

Examples of the compound (a2) include glycidyl acrylate, glycidyl methacrylate, glycidyl α-ethyl acrylate, glycidyl α-n-propyl acrylate, glycidyl α-n-butyl acrylate, and 3,4-acrylic acid. Epoxy butyl, 3,4-epoxy butyl methacrylate, 3,4-epoxy butyl α-ethyl acrylate, 6,7-epoxy heptyl acrylate, 6,7-epoxy heptyl methacrylate, α-ethyl acrylate 6,7 -Epoxyheptyl, β-methylglycidyl acrylate, β-methylglycidyl methacrylate, β-ethylglycidyl acrylate, β-ethylglycidyl methacrylate, β-n-propyl glycidyl acrylate, β-n-propyl glycidyl methacrylate, 3,4-epoxycyclohexyl acrylate And carboxylic acid esters such as 3,4-epoxycyclohexyl methacrylate; ethers such as o-vinylbenzyl glycidyl ether, m-vinylbenzyl glycidyl ether, and p-vinylbenzyl glycidyl ether.
Among these compounds (a2), glycidyl methacrylate, 6,7-epoxyheptyl methacrylate, 3,4-epoxycyclohexyl methacrylate, β-methylglycidyl methacrylate, o-vinylbenzyl glycidyl ether, m-vinylbenzyl glycidyl Ether, p-vinylbenzylglycidyl ether and the like are preferable from the viewpoint of increasing the copolymerization reactivity and the strength of the obtained spacer.
The said compound (a2) can be used individually or in mixture of 2 or more types.

  [A] In the copolymer, the content of the structural unit derived from the compound (a2) is preferably 10 to 70% by weight, particularly preferably 20 to 60% by weight. In this case, if the content of the structural unit is less than 10% by weight, the compressive strength, heat resistance and chemical resistance of the resulting spacer tend to decrease, whereas if it exceeds 70% by weight, the radiation-sensitive resin. The storage stability of the composition tends to decrease.

Examples of the compound (a3) include acrylic acid such as methyl acrylate, ethyl acrylate, n-propyl acrylate, i-propyl acrylate, n-butyl acrylate, i-butyl acrylate, sec-butyl acrylate, and t-butyl acrylate. Alkyl esters; methacrylic acid alkyl esters such as methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, i-propyl methacrylate, n-butyl methacrylate, i-butyl methacrylate, sec-butyl methacrylate, t-butyl methacrylate; cyclohexyl acrylate, 2-methylcyclohexyl acrylate, tricyclo [5.2.1.0 ^2,6 ] decan-8-yl acrylate (hereinafter referred to as “tricyclo [5.2.1.0 ^{2 , 6} ] decan-8-yl "is referred to as" dicyclopentanyl "), alicyclic esters of acrylic acid such as 2-dicyclopentanyloxyethyl acrylate, isobornyl acrylate, tetrahydrofuryl acrylate, etc .; cyclohexyl Methacrylic acid alicyclic esters such as methacrylate, 2-methylcyclohexyl methacrylate, dicyclopentanyl methacrylate, 2-dicyclopentanyloxyethyl methacrylate, isobornyl methacrylate, tetrahydrofuryl methacrylate; phenyl acrylate, benzyl acrylate, etc. Acrylic acid aryl esters; Methacrylic acid aryl esters such as phenyl methacrylate and benzyl methacrylate; Diesters such as diethyl maleate, diethyl fumarate and diethyl itaconate Rubonic acid diesters; acrylic acid hydroxyalkyl esters such as 2-hydroxyethyl acrylate and 2-hydroxypropyl acrylate; methacrylic acid hydroxyalkyl esters such as 2-hydroxyethyl methacrylate and 2-hydroxypropyl methacrylate; styrene, α-methyl Aromatic vinyl compounds such as styrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, acrylonitrile, methacrylonitrile, vinyl chloride, vinylidene chloride, acrylamide, methacrylamide, vinyl acetate, 1,3-butadiene, Isoprene, 2,3-dimethyl-1,3-butadiene, N-cyclohexylmaleimide, N-phenylmaleimide, N-benzylmaleimide, N-succinimidyl-3-maleimide Nzoate, N-succinimidyl-4-maleimidobutyrate, N-succinimidyl-6-maleimidocaproate, N-succinimidyl-3-maleimidopropionate, N- (9-acridinyl) maleimide and the like.

Of these compounds (a3), 2-methylcyclohexyl acrylate, t-butyl methacrylate, dicyclopentanyl methacrylate, styrene, p-methoxystyrene, 1,3-butadiene and the like are preferable from the viewpoint of copolymerization reactivity.
The said compound (a3) can be used individually or in mixture of 2 or more types.
[A] In the copolymer, the content of the structural unit derived from the compound (a3) is preferably 10 to 80% by weight, particularly preferably 20 to 60% by weight. In this case, if the content of the structural unit is less than 10% by weight, the storage stability of the radiation-sensitive resin composition may be lowered, whereas if it exceeds 80% by weight, the developability may be lowered. is there.

[A] The polystyrene-reduced weight average molecular weight (hereinafter referred to as “Mw”) by gel permeation chromatography (GPC) of the copolymer is usually 2 × 10 ^{3 to} 5 × 10 ⁵ , preferably 5 × 10 ³ to 1 × 10 ⁵ . In this case, the Mw of the [A] copolymer is 2 ×
If it is less than 10 ³ , the compressive strength and heat resistance of the resulting spacer tend to decrease, while if it exceeds 5 × 10 ⁵ , developability tends to decrease.
In the present invention, the [A] copolymer can be used alone or in admixture of two or more.

[A] The copolymer can be produced by radical polymerization of the compound (a1), the compound (a2) and the compound (a3) in a solvent in the presence of a polymerization initiator, for example. [A] As a solvent used in the production of the copolymer, for example,
Alcohols such as methanol and ethanol; ethers such as tetrahydrofuran; ethylene glycol ethers such as ethylene glycol monomethyl ether and ethylene glycol monoethyl ether; ethylene glycol alkyl ether acetates such as ethylene glycol methyl ether acetate and ethylene glycol ethyl ether acetate Diethylene glycol ethers such as diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol ethyl methyl ether; propylene glycol methyl ether, propylene glycol ethyl ether, propylene glycol-n-propyl ether; Propylene glycol ethers such as propylene glycol-n-butyl ether; propylene glycol alkyl ether acetates such as propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, propylene glycol-n-propyl ether acetate, propylene glycol-n-butyl ether acetate; Propylene glycol alkyl ether propionates such as propylene glycol methyl ether propionate, propylene glycol ethyl ether propionate, propylene glycol-n-propyl ether propionate, propylene glycol-n-butyl ether propionate; toluene, xylene Aromatic hydrocarbons such as methyl ethyl ketone, cyclohexane Sanon, ketones such as 4-hydroxy-4-methyl-2-pentanone;

Methyl acetate, ethyl acetate, n-propyl acetate, n-butyl acetate, methyl hydroxyacetate, ethyl hydroxyacetate, n-propyl hydroxyacetate, n-butyl hydroxyacetate, methyl lactate, ethyl lactate, n-propyl lactate, n-lactic acid Butyl, methyl 3-hydroxypropionate, ethyl 3-hydroxypropionate, n-propyl 3-hydroxypropionate, n-butyl 3-hydroxypropionate, methyl 2-hydroxy-2-methylpropionate, 2-hydroxy-2 -Ethyl methylpropionate, methyl 2-hydroxy-3-methylbutanoate, methyl methoxyacetate, ethyl methoxyacetate, n-propyl methoxyacetate, n-butyl methoxyacetate, methyl ethoxyacetate, ethyl ethoxyacetate, n-propyl ethoxyacetate, Ethoxyacetic acid n- Chill, n-propoxyacetate methyl, n-propoxyacetate ethyl, n-propoxyacetate n-propyl, n-propoxyacetate n-butyl, n-butoxyacetate methyl, n-butoxyacetate, n-butoxyacetate n-propyl, n-Butoxyacetate n-butyl, 2-methoxypropionate methyl, 2-methoxypropionate ethyl, 2-methoxypropionate n-propyl, 2-methoxypropionate n-butyl, 2-ethoxypropionate methyl, 2-ethoxy Ethyl propionate, n-propyl 2-ethoxypropionate, n-butyl 2-ethoxypropionate, methyl n-propoxypropionate, ethyl n-propoxypropionate, n-propyl n-propoxypropionate, n-propoxypropionic acid n-butyl, 2-n-butoxy Methyl lopionate, ethyl 2-n-butoxypropionate, n-propyl 2-n-butoxypropionate, n-butyl 2-n-butoxypropionate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, 3 -N-propyl methoxypropionate, n-butyl 3-methoxypropionate, methyl 3-ethoxypropionate, ethyl 3-ethoxypropionate, n-propyl 3-ethoxypropionate, n-butyl 3-ethoxypropionate, 3 -Methyl n-propoxypropionate, ethyl 3-n-propoxypropionate, n-propyl 3-n-propoxypropionate, n-butyl 3-n-propoxypropionate, methyl 3-n-butoxypropionate, 3- n-Butoxypropionate ethyl, 3-n-butoxypro Other esters such as n-propyl pionate and n-butyl 3-n-butoxypropionate can be mentioned.

  Moreover, as a polymerization initiator used for manufacture of [A] copolymer, what is generally known as a radical polymerization initiator can be used, for example, 2,2'-azobisisobutyronitrile, 2,2'-azobis- (2,4-dimethylvaleronitrile), 2,2'-azobis- (4-methoxy-2,4-dimethylvaleronitrile), 4,4'-azobis (4-cyanovaleric acid ), Dimethyl-2,2′-azobis (2-methylpropionate), 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile); benzoyl peroxide, lauroyl peroxide, t -Organic peroxides such as butylperoxypivalate and 1,1'-bis- (t-butylperoxy) cyclohexane; hydrogen peroxide and the like. When a peroxide is used as the radical polymerization initiator, a redox initiator may be used in combination with a reducing agent.

-[B] polymerizable unsaturated compound-
The polymerizable unsaturated compound in the radiation-sensitive resin composition of the present invention is preferably a bifunctional or higher functional acrylate and methacrylate (hereinafter referred to as “(meth) acrylate”).
Examples of the bifunctional (meth) acrylate include ethylene glycol acrylate, ethylene glycol methacrylate, 1,6-hexanediol diacrylate, 1,6-hexanediol dimethacrylate, 1,9-nonanediol diacrylate, 1,9. -Nonanediol dimethacrylate, tetraethylene glycol diacrylate, tetraethylene glycol dimethacrylate, polypropylene glycol diacrylate, polypropylene glycol dimethacrylate, bisphenoxyethanol full orange acrylate, bisphenoxyethanol full orange methacrylate, and the like.

  Moreover, as a commercial item of bifunctional (meth) acrylate, for example, Aronix M-210, M-240, M-6200 (above, manufactured by Toagosei Co., Ltd.), KAYARAD HDDA, KAYARAD HX-220, R-604, UX-2201, UX-2301, UX-3204, UX-3301, UX-4101, UX-6101, UX-7101, UX-8101, MU-2100, MU-4001 (above, Nippon Kayaku (Manufactured by Co., Ltd.), Biscoat 260, 312 and 335HP (manufactured by Osaka Organic Chemical Industry Co., Ltd.).

  Examples of the tri- or higher functional (meth) acrylate include trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol triacrylate, pentaerythritol trimethacrylate, pentaerythritol tetraacrylate, pentaerythritol tetramethacrylate, dipentaerythritol pentaacrylate. , Dipentaerythritol pentamethacrylate, dipentaerythritol hexaacrylate, dipentaerythritol hexamethacrylate, tri (2-acryloyloxyethyl) phosphate, tri (2-methacryloyloxyethyl) phosphate, ) As an acrylate, it has a linear alkylene group and an alicyclic structure, and two or more iso Urethane acrylate obtained by reacting a compound having an anate group with a compound having one or more hydroxyl groups in the molecule and having three, four or five acryloyloxy groups and / or methacryloyloxy groups And the like, and the like.

Moreover, as a commercial item of (meth) acrylate more than trifunctional, for example, Aronix M-309, the same -400, the same -402, the same -405, the same -450, the same -1310, the same -1600, the same -1960 -7100, -8030, -8060, -8100, -8530, -8560, -8560, -9050, Aronix TO-1450 (manufactured by Toagosei Co., Ltd.), KAYARAD TMPTA, DPHA, DPCA-20, DPCA-30, DPCA-60, DPCA-120, DPCA-120, MAX-3510 (manufactured by Nippon Kayaku Co., Ltd.), Biscote 295, 300, 360, GPT, 3PA , 400 (above, manufactured by Osaka Organic Chemical Industry Co., Ltd.) and urethane acrylate compounds such as New Frontier R-1150 (1st Work made by Pharmaceutical Co., Ltd.), can be mentioned KAYARAD DPHA-40H (manufactured by Nippon Kayaku Co., Ltd.), and the like.
In this invention, a polymerizable unsaturated compound can be used individually or in mixture of 2 or more types.

  In the radiation-sensitive resin composition of the present invention, the amount of the polymerizable unsaturated compound used is preferably 30 to 200 parts by weight, particularly preferably 50 to 140 parts by weight with respect to 100 parts by weight of the [A] copolymer. It is. In this case, if the amount of the polymerizable unsaturated compound used is less than 30 parts by weight, the resulting spacer tends to be thin and the strength tends to decrease. On the other hand, if it exceeds 200 parts by weight, Adhesion may be insufficient.

-[C] biimidazole compound-
Examples of the biimidazole compound used in the present invention include a compound represented by the following general formula (1) (hereinafter referred to as “biimidazole compound (C1)”) and a general formula (2). Compound (hereinafter referred to as “biimidazole compound (C2)”) and the like.

〔式中、Ｘは水素原子、ハロゲン原子、シアノ基、炭素数１〜４のアルキル基または炭素数６〜９のアリール基を示し、Ａは−ＣＯＯ−Ｒ（但し、Ｒは炭素数１〜４のアルキル基または炭素数６〜９のアリール基を示す。）を示し、ｎは１〜３の整数であり、各ｍは１〜３の整数である。〕

[Wherein, X represents a hydrogen atom, a halogen atom, a cyano group, an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 9 carbon atoms, A represents —COO—R (where R represents 1 to 4 is an alkyl group of 4 or an aryl group of 6 to 9 carbon atoms.), N is an integer of 1 to 3, and each m is an integer of 1 to 3. ]

（式中、Ｘ¹ 、Ｘ² およびＸ³ は相互に独立に水素原子、ハロゲン原子、シアノ基、炭素数１〜４のアルキル基または炭素数６〜９のアリール基を示す。但し、Ｘ¹ 、Ｘ² およびＸ³ の２個以上が同時に水素原子をとることはない。）

(Wherein X ¹ , X ² and X ³ each independently represent a hydrogen atom, a halogen atom, a cyano group, an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 9 carbon atoms, provided that X ¹ , X ² and X ³ do not take a hydrogen atom at the same time.)

Examples of biimidazole compounds include:
2,2′-bis (2-chlorophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (2-chlorophenyl) -4,4 ′, 5,5′-trakis (4-Ethoxycarbonylphenyl) biimidazole, 2,2′-bis (2-chlorophenyl) -4,4 ′, 5,5′-tetrakis (4-phenoxycarbonylphenyl) biimidazole, 2,2′-bis ( 2,4-dichlorophenyl) -4,4 ', 5,5'-tetrakis (4-ethoxycarbonylphenyl) biimidazole, 2,2'-bis (2,4-dichlorophenyl) -4,4', 5,5 '-Tetrakis (4-phenoxycarbonylphenyl) biimidazole, 2,2'-bis (2,4,6-trichlorophenyl) -4,4', 5,5'-tetrakis (4-ethoxycarbonylphenyl) biimidazole Midazole, 2,2′-bis (2,4,6-trichlorophenyl) -4,4 ′, 5,5′-tetrakis (4-phenoxycarbonylphenyl) biimidazole, 2,2′-bis (2-cyano) Phenyl) -4,4 ′, 5.5′-tetrakis (4-ethoxycarbonylphenyl) biimidazole, 2,2′-bis (2-cyanophenyl) -4,4 ′, 5,5′-tetrakis (4 -Phenoxycarbonylphenyl) biimidazole, 2,2'-bis (2-methylphenyl) -4,4 ', 5,5'-tetrakis (4-methoxycarbonylphenyl) biimidazole, 2,2'-bis (2 -Methylphenyl) -4,4 ', 5,5'-tetrakis (4-ethoxycarbonylphenyl) biimidazole, 2,2'-bis (2-methylphenyl) -4,4', 5,5'-tetrakis ( -Phenoxycarbonylphenyl) biimidazole, 2,2'-bis (2-ethylphenyl) -4,4 ', 5,5'-tetrakis (4-methoxycarbonylphenyl) biimidazole, 2,2'-bis (2 -Ethylphenyl) -4,4 ', 5,5'-tetrakis (4-ethoxycarbonylphenyl) biimidazole, 2,2'-bis (2-ethylphenyl) -4,4', 5,5'-tetrakis (4-phenoxycarbonylphenyl) biimidazole, 2,2′-bis (2-phenylphenyl) -4,4 ′, 5,5′-tetrakis (4-methoxycarbonylphenyl) biimidazole, 2,2′-bis (2-Phenylphenyl) -4,4 ′, 5,5′-tetrakis (4-ethoxycarbonylphenyl) biimidazole, 2,2′-bis (2-phenylphenyl) -4 4 ', 5,5'-tetrakis (4-phenoxycarbonylphenyl) bicycloalkyl biimidazole-based compounds such as imidazole (C1);

2,2′-bis (2,4-dichlorophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (2,4,6-trichlorophenyl) -4,4 ′ , 5,5′-tetraphenylbiimidazole, 2,2′-bis (2,4-dibromophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (2, 4,6-tribromophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (2,4-dicyanophenyl) -4,4 ′, 5,5′-tetra Phenylbiimidazole, 2,2'-bis (2,4,6-tricyanophenyl) -4,4 ', 5,5'-tetraphenylbiimidazole, 2,2'-bis (2,4-dimethylphenyl) ) -4,4 ', 5,5'-tetraphenylbiimi Sol, 2,2′-bis (2,4,6-trimethylphenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (2,4-diethylphenyl) -4 , 4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (2,4,6-triethylphenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2 ′ -Bis (2,4-diphenylphenyl) -4,4 ', 5,5'-tetraphenylbiimidazole, 2,2'-bis (2,4,6-triphenylphenyl) -4,4', 5 Biimidazole compounds (C2) such as, 5′-tetraphenylbiimidazole and the like can be mentioned.

Among these biimidazole compounds, in particular, 2,2′-bis (2-chlorophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (2-chlorophenyl) -4,4 ', 5,5'-tetrakis (4-ethoxycarbonylphenyl) biimidazole, 2,2'-bis (2-bromophenyl) -4,4', 5,5'-tetrakis (4-ethoxy) Carbonylphenyl) biimidazole, 2,2′-bis (2,4-dichlorophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (2,4-dibromophenyl)- 4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (2,4,6-trichlorophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2 '-Bis (2,4,6-Tribro Mophenyl) -4,
4 ′, 5,5′-tetraphenylbiimidazole and the like are preferable.
Biimidazole compound (C1) and biimidazole compound (C2) are excellent in solubility in solvents, do not generate foreign matters such as undissolved substances and precipitates, and have high sensitivity and cut wavelengths of 350 nm or less. Even with the irradiated radiation, it is possible to sufficiently advance the curing reaction by exposure with a small amount of energy and to form an excellent spacer without pattern loss, deficiency or undercut.
In the present invention, biimidazole compounds can be used alone or in admixture of two or more.

  In the radiation-sensitive resin composition of the present invention, the amount of the biimidazole compound used is preferably 0.1 to 50 parts by weight, particularly preferably 1 to 35 parts by weight, based on 100 parts by weight of the [A] copolymer. Part. In this case, if the amount of the biimidazole compound used is less than 0.1 parts by weight, the resulting spacer tends to cause film slippage or a decrease in strength, while if it exceeds 50 parts by weight, There is a tendency that the effluent increases and the voltage holding ratio tends to decrease.

-[D] Carbonyl group-containing polymerization initiator-
The component [D] in the present invention is a radiation-sensitive polymerization initiator having a carbonyl group (hereinafter referred to as “[D] carbonyl group-containing polymerization initiator”), and has an action of adjusting the shape of the spacer to be formed. It is an ingredient.
[D] Examples of the carbonyl group-containing polymerization initiator include α-diketones such as benzyl and diacetyl; acyloins such as benzoin; acyloin ethers such as benzoin methyl ether, benzoin ethyl ether and benzoin isopropyl ether; thioxanthone, Benzophenones such as 2,4-diethylthioxanthone, thioxanthone-4-sulfonic acid, benzophenone, 4,4′-bis (dimethylamino) benzophenone, 4,4′-bis (diethylamino) benzophenone; acetophenone, 4-dimethylaminoacetophenone , Α, α′-dimethoxyacetoxybenzophenone, 2,2′-dimethoxy-2-phenylacetophenone, 4-methoxyacetophenone, 2-methyl [4- (methylthio) phenyl] -2-morpholino-1 Acetophenones such as propanone and 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1; quinones such as anthraquinone and 1,4-naphthoquinone; 2,4,6-trimethylbenzoyl Phosphine oxides such as diphenylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide, etc. Can be mentioned.

[D] Commercially available products of carbonyl group-containing polymerization initiators include, for example, IRGACURE-124, 149, 184, 369, -500, 651, -819, and 907. -1700, -11000, -1800, -1850, -2959, Darocur-1173, -1116, -1664, -2959, -4959 (above, manufactured by Ciba Specialty Chemicals) ), KAYACURE-DETX, same-MBP, same-DMBI, same-EPA, same-OA (manufactured by Nippon Kayaku Co., Ltd.), LUCIRIN TPO (manufactured by BASF Co. LTD), VICURE-10, same-55 (Thus, STAUFER Co. LTD) and the like.
In the present invention, the [D] carbonyl group-containing polymerization initiator can be used alone or in admixture of two or more.

  In the radiation-sensitive resin composition of the present invention, the amount of the [D] carbonyl group-containing polymerization initiator used is preferably 1 to 50 parts by weight, particularly preferably 3 to 100 parts by weight of the [A] copolymer. -30 parts by weight. In this case, if the amount of the [D] carbonyl group-containing polymerization initiator used is less than 1 part by weight, the resulting spacer tends to cause film slippage or pattern shape failure, whereas if it exceeds 100 parts by weight. There is a possibility that the size of the pattern to be obtained is larger than the allowable size than the design size of the mask pattern.

-[E] Compound having a dialkylamino group-
The compound having a dialkylamino group in the radiation-sensitive resin composition of the present invention is not particularly limited as long as it has an effect of sensitizing the [C] biimidazole compound. , 4′-bis (dimethylamino) benzophenone, 4,4′-bis (diethylamino) benzophenone, ethyl p-dimethylaminobenzoate, ethyl p-diethylaminobenzoate, i-amyl p-dimethylaminobenzoate, p-diethylamino Aromatic compounds such as i-amyl benzoate can be mentioned. However, as in the case of 4,4′-bis (dimethylamino) benzophenone and 4,4′-bis (diethylamino) benzophenone, compounds having a dialkylamino group are included in the category of [D] carbonyl group-containing polymerization initiator. When used, a compound different from the component [D] is used.
Of these compounds having a dialkylamino group, 4,4′-bis (diethylamino) benzophenone is particularly preferable.
In this invention, the compound which has a dialkylamino group can be used individually or in mixture of 2 or more types.

  In the radiation-sensitive resin composition of the present invention, the amount of the compound having a dialkylamino group is preferably 0.1 to 50 parts by weight, particularly preferably 1 to 100 parts by weight with respect to 100 parts by weight of the [A] copolymer. 20 parts by weight. In this case, if the amount of the compound having a dialkylamino group is less than 0.1 parts by weight, the resulting spacer tends to be poor in film slippage or pattern shape, whereas if it exceeds 50 parts by weight, There is a tendency that a defect in the pattern shape tends to occur.

-[F] thiol compound-
The thiol compound in the radiation sensitive resin composition of the present invention is a component having an action of donating a hydrogen radical to the [C] biimidazole compound.
That is, the [C] biimidazole compound is sensitized by the compound having an [E] dialkylamino group and cleaved to generate an imidazole radical. In this case, if there is no thiol compound, a high radical is generated. The polymerization initiating ability is not expressed, and the obtained spacer often has an unfavorable shape such as a reverse taper shape. However, by adding a thiol compound to a system in which a [C] biimidazole compound and a compound having an [E] dialkylamino group coexist, a hydrogen radical is donated to the imidazole radical, so that the imidazole radical is neutral. In addition to conversion to imidazole, a component having a sulfur radical having a high polymerization initiating ability is generated, whereby the spacer can have a more preferable forward taper shape.

  Examples of the thiol compound include aromatic compounds such as 2-mercaptobenzothiazole, 2-mercaptobenzoxazole, 2-mercaptobenzimidazole, 2-mercapto-5-methoxybenzothiazole, 2-mercapto-5-methoxybenzimidazole. Compound; aliphatic monothiol compounds such as 3-mercaptopropionic acid, methyl 3-mercaptopropionate, ethyl 3-mercaptopropionate and n-octyl 3-mercaptopropionate; 3,6-dioxa-1,8-octane Examples thereof include aliphatic polythiol compounds such as dithiol, pentaerythritol tetra (mercaptoacetate), pentaerythritol tetra (3-mercaptopropionate), and the like.

  In the radiation sensitive resin composition of the present invention, the amount of the thiol compound used is preferably 0.1 to 50 parts by weight, particularly preferably 1 to 20 parts by weight per 100 parts by weight of the [C] biimidazole compound. Part. In this case, if the amount of the thiol-based compound used is less than 0.1 parts by weight, the resulting spacer tends to cause film slippage or pattern shape defects, whereas if it exceeds 50 parts by weight, the pattern shape There is a tendency to cause defects.

-Optional additives-
In the radiation-sensitive resin composition of the present invention, optional additives other than those described above, for example, an adhesion aid, a surfactant, a storage stabilizer, and a heat resistance improvement are added as necessary, as long as the effects of the present invention are not impaired. An agent or the like can be blended.
The adhesion assistant is a component used for improving the adhesion between the formed spacer and the substrate.
As such an adhesion assistant, a functional silane coupling agent having a reactive functional group such as a carboxyl group, a methacryloyl group, a vinyl group, an isocyanate group, and an epoxy group is preferable. Examples thereof include trimethoxysilylbenzoic acid. , Γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, vinyltrimethoxysilane, γ-isocyanatopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyl A trimethoxysilane etc. 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 20 parts by weight or less with respect to 100 parts by weight of the [A] copolymer. In this case, when the compounding amount of the adhesion assistant exceeds 20 parts by weight, there is a tendency that a development residue is likely to occur.

Moreover, the said surfactant is a component used in order to improve applicability | paintability.
As such a surfactant, for example, a fluorine-based surfactant, a silicone-based surfactant and the like are preferable.
The fluorine-based surfactant is preferably a compound having a fluoroalkyl group and / or a fluoroalkylene group in at least one of the terminal, main chain and side chain, and examples thereof include 1,1,2,2 -Tetrafluoro-n-octyl (1,1,2,2-tetrafluoro-n-propyl) ether, 1,1,2,2-tetrafluoro-n-octyl (n-hexyl) ether, hexaethylene glycol di (1, 1,2,2,3,3-hexafluoro-n-pentyl) ether, octaethylene glycol di (1,1,2,2-tetrafluoro-n-butyl) ether, hexapropylene glycol di (1,1,2, 2,3,3-hexafluoro-n-pentyl) ether, octapropylene glycol di (1,1,2,2-tetrafluoro-n- Til) ether, sodium perfluoro-n-dodecanesulfonate, 1,1,2,2,3,3-hexafluoro-n-decane, 1,1,2,2,8,8,9,9,10,10 -Decafluoro-n-dodecane, sodium fluoroalkylbenzenesulfonates, sodium fluoroalkylphosphates, sodium fluoroalkylcarboxylates, diglycerin tetrakis (fluoroalkylpolyoxyethylene ether), fluoroalkylammonium iodides, fluoroalkyl Examples include betaines, other fluoroalkyl polyoxyethylene ethers, perfluoroalkyl polyoxyethanols, perfluoroalkyl alkoxylates, and carboxylic acid fluoroalkyl esters.

  Examples of commercially available fluorosurfactants include BM-1000, BM-1100 (above, manufactured by BM CHEMIE), MegaFuck F142D, F172, F173, F183, F183, F178, F191, F471, F476 (above, Dainippon Ink & Chemicals, Inc.), Florard FC-170C, -171, -430, -431 (above, Sumitomo 3M Limited), Surflon S-112 -113, -131, -141, -145, -382, Surflon SC-101, -102, -103, -104, -105, -106 (above, Asahi Glass ( Co., Ltd.), Ftop EF301, 303, 352 (above, Shin-Akita Kasei Co., Ltd.), Footent FT-100, -110, -140A The -150, the -250, the -251, the -300, the -310, the same -400S, Ftergent FTX-218, the -251 (or more, (Ltd.) NEOS), and the like can be given.

  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.

Further, as surfactants other than the above, polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether; polyoxyethylene-n-octylphenyl ether, polyoxyethylene- polyoxyethylene aryl ethers such as n-nonylphenyl ether; nonionic surfactants such as polyoxyethylene dialkyl esters such as polyoxyethylene dilaurate and polyoxyethylene distearate; and organosiloxane polymer KP341 (Shin-Etsu Chemical Co., Ltd.) Manufactured by Co., Ltd.), (meth) acrylic acid copolymer polyflow No. 57, no. 95 (manufactured by Kyoeisha Chemical Co., Ltd.).
These surfactants can be used alone or in admixture of two or more.

  The compounding amount of the surfactant is preferably 1.0 part by weight or less, and more preferably 0.5 part by weight or less with respect to 100 parts by weight of the [A] copolymer. In this case, when the compounding amount of the surfactant exceeds 1.0 part by weight, film unevenness tends to occur.

Examples of the storage stabilizer include sulfur, quinones, hydroquinones, polyoxy compounds, amines, nitronitroso compounds and the like. More specifically, 4-methoxyphenol, N-nitroso-N- Examples include phenylhydroxylamine aluminum.
These storage stabilizers can be used alone or in admixture of two or more.
The blending amount of the storage stabilizer is preferably 3.0 parts by weight or less, more preferably 0.5 parts by weight or less with respect to 100 parts by weight of the [A] copolymer. In this case, when the amount of the storage stabilizer exceeds 3.0 parts by weight, the sensitivity may be lowered and the pattern shape may be deteriorated.

Examples of the heat resistance improver include N- (alkoxymethyl) glycoluril compounds, N- (alkoxymethyl) melamine compounds, and compounds having two or more epoxy groups.
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) glycoluril , N, N, N, N-tetra (t-butoxymethyl) glycoluril and the like.
Of these N- (alkoxymethyl) glycoluril compounds, N, N, N, N-tetra (methoxymethyl) glycoluril is preferred.

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, Examples thereof include N, N, N-hexa (n-butoxymethyl) melamine, N, N, N, N, N, N-hexa (t-butoxymethyl) melamine and the like.
Of these N- (alkoxymethyl) melamine compounds, N, N, N, N, N, N-hexa (methoxymethyl) melamine is preferred, and examples of commercially available products thereof include Nicalac N-2702 and MW- 30M (manufactured by Sanwa Chemical Co., Ltd.).

Examples of the compound having two or more epoxy groups include ethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, triethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, dipropylene glycol diglycidyl. Ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerin diglycidyl ether, trimethylolpropane triglycidyl ether, hydrogenated bisphenol A diglycidyl Mention ether, bisphenol A diglycidyl ether, etc. Kill.
Examples of commercially available compounds having two or more epoxy groups include Epolite 40E, 100E, 200E, 70P, 200P, 400P, 1500NP, 80MF, 100MF, 1600, 3002 and 4000 (manufactured by Kyoeisha Chemical Co., Ltd.).
These heat resistance improvers can be used alone or in admixture of two or more.

The radiation-sensitive resin composition of the present invention is preferably used as a composition solution dissolved in an appropriate solvent.
As said solvent, what melt | dissolves each essential component and arbitrary additive component of the radiation sensitive resin composition of this invention uniformly, and does not react with each component is used.
As such a solvent, for example,
Alcohols such as methanol and ethanol; ethers such as tetrahydrofuran; ethylene glycol ethers such as ethylene glycol monomethyl ether and ethylene glycol monoethyl ether; ethylene glycol alkyl ether acetates such as ethylene glycol methyl ether acetate and ethylene glycol ethyl ether acetate Diethylene glycol ethers such as diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol ethyl methyl ether;

Propylene glycol ethers such as propylene glycol methyl ether, propylene glycol ethyl ether, propylene glycol n-propyl ether, propylene glycol n-butyl ether; propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, propylene glycol n-propyl ether acetate, propylene Propylene glycol alkyl ether acetates such as glycol n-butyl ether acetate; propylene glycol methyl ether propionate, propylene glycol ethyl ether propionate, propylene glycol n-propyl ether propionate, propylene glycol n-butyl ether propionate, etc. Propylene glycol Ruki ether propionate like;

Aromatic hydrocarbons such as toluene and xylene; ketones such as methyl ethyl ketone, cyclohexanone and 4-hydroxy-4-methyl-2-pentanone; methyl acetate, ethyl acetate, n-propyl acetate, n-butyl acetate, 2-hydroxy Methyl 2-methylpropionate, ethyl 2-hydroxy-2-methylpropionate, methyl hydroxyacetate, ethyl hydroxyacetate, hydroxyacetate n-propyl, hydroxyacetate n-butyl, methyl lactate, ethyl lactate, n-propyl lactate, N-butyl lactate, methyl 3-hydroxypropionate, ethyl 3-hydroxypropionate, n-propyl 3-hydroxypropionate, n-butyl 3-hydroxypropionate, methyl 3-butoxypropionate, ethyl 3-butoxypropionate , 3-butoxypro Propionic acid n- propyl, mention may be made of other esters such as 3-butoxy-propionic acid n- butyl.

Of these solvents, ethylene glycol ethers, ethylene glycol alkyl ether acetates, diethylene glycol ethers and other esters are preferred from the standpoints of solubility, reactivity with each component, and ease of film formation.
The said solvent can be used individually or in mixture of 2 or more types.

In the present invention, a high boiling point solvent may be used in combination with the solvent.
Examples of the high boiling point solvent 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 alcohol, benzyl acetate, ethyl benzoate, diethyl oxalate, diethyl maleate, γ-butyrolactone, ethylene carbonate, carbonic acid Examples include propylene and phenyl cellosolve acetate.
These high boiling point solvents can be used alone or in admixture of two or more.
Further, the composition solution prepared as described above can be used after being filtered using a Millipore filter having a pore size of about 0.5 μm.

Method of forming spacers Next, a method of forming a spacer of the present invention will be described with reference to radiation-sensitive resin composition of the present invention.
The method for forming a spacer of the present invention includes at least the following steps (a) to (d).
(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 film to radiation that does not contain a wavelength of less than 350 nm.
(C) A step of developing the film after exposure.
(D) A step of heating the film after development.

Hereinafter, each of these steps will be described sequentially.
-(I) Process-
A transparent conductive film is formed on one surface of a transparent substrate, the composition solution of the radiation-sensitive resin composition of the present invention is applied on the transparent conductive film, and then the coated surface is heated (prebaked) to form a coating film. Form.
Examples of the transparent substrate used for forming the spacer include a glass substrate and a resin substrate. More specifically, glass substrates such as soda lime glass and non-alkali glass; polyethylene terephthalate, polybutylene terephthalate, Examples thereof include a resin substrate made of a plastic such as polyethersulfone, polycarbonate, and polyimide.
As a transparent conductive film provided on one surface of a transparent substrate, an NESA film (registered trademark of PPG, USA) made of tin oxide (SnO ₂ ), an ITO film made of indium oxide-tin oxide (In ₂ O ₃ -SnO ₂ ) Etc.
As a method for applying the composition solution, for example, an appropriate method such as a spray method, a roll coating method, or a spin coating method can be employed.
Moreover, although the conditions of prebaking differ also with the kind of each component, a mixture ratio, etc., it is normally about 1 to 15 minutes at 70-120 degreeC.

-(B) Process-
Next, at least a part of the formed film is exposed to radiation substantially free of wavelengths less than 350 nm. In this case, when exposing a part of the film, the exposure is performed through a predetermined pattern mask. In the present invention, it is possible to effectively suppress the life reduction of the mirror used in the exposure machine by cutting radiation having a high energy and a wavelength of less than 350 nm.
Visible light, ultraviolet light, far ultraviolet light, or the like can be used as the radiation used for exposure, but radiation having a wavelength in the range of 190 to 450 nm is preferably less than 350 nm.
The exposure amount is usually 100 to 10,000 J / m ² , preferably 1,500, as a value obtained by measuring the intensity of the exposed radiation at a wavelength of 365 nm with an illuminometer (OAI model 356, manufactured by OAI Optical Associates Inc.). to 3, it is 000J / m ^2.
The method for cutting the wavelength of radiation less than 350 nm is not particularly limited, and for example, a method using a filter can be employed.
As the filter, for example, an ultraviolet transmission filter “UV-35” manufactured by Toshiba Glass Co., Ltd. can be employed.
The emission spectrum (thick line) of the mercury lamp that has passed through the ultraviolet transmission filter “UV-35” and the emission spectrum of the mercury lamp that has not been transmitted (thin line. However, the emission spectrum of 350 nm or more partially overlaps the thick line. ) Is shown in FIG. Although the emission spectrum (thick line) in FIG. 1 includes a slight wavelength of less than 350 nm, its relative intensity and accumulated area are sufficiently small, and it does not adversely affect the lifetime of the mirror used in the exposure machine.

-(C) Process-
Subsequently, the exposed film is developed to remove unnecessary portions and form a predetermined pattern.
Examples of the developer used for development include inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, and ammonia; and aliphatic primary grades such as ethylamine and n-propylamine. Amines; aliphatic secondary amines such as diethylamine and di-n-propylamine; aliphatic tertiary amines such as trimethylamine, methyldiethylamine, dimethylethylamine and triethylamine; pyrrole, piperidine, N-methylpiperidine, N-methyl Alicyclic tertiary amines such as pyrrolidine, 1,8-diazabicyclo [5.4.0] -7-undecene, 1,5-diazabicyclo [4.3.0] -5-nonene; pyridine, collidine, lutidine , Aromatic tertiary amines such as quinoline; dimethylethanolamine, methyl Ethanolamine, alkanolamines such as triethanolamine; tetramethylammonium hydroxide, may be used an aqueous solution of an alkaline compound such as quaternary ammonium salts such as tetraethyl ammonium hydroxide.
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.
As a developing method, any of a liquid filling method, a dipping method, a shower method and the like may be used, and the developing time is usually about 10 to 180 seconds at room temperature.
After development, for example, after washing with running water for 30 to 90 seconds, a desired pattern is formed by, for example, air drying with compressed air or compressed nitrogen.

-(D) Process-
Next, the obtained pattern is heated at a predetermined temperature, for example, 100 to 160 ° C., for a predetermined time, for example, 5 to 30 minutes on the hot plate, for 30 to 180 minutes in the oven, by a heating device such as a hot plate or oven. A predetermined spacer can be obtained by heating (post-baking).
The conventional radiation-sensitive resin composition used for the formation of the spacer cannot exhibit sufficient performance unless the heat treatment is performed at a temperature of about 180 to 200 ° C. or higher. The radiation sensitive resin composition can be heated at a lower temperature than before, and as a result, without causing yellowing or deformation of the resin substrate, compressive strength, rubbing resistance during liquid crystal alignment, A spacer excellent in various performances such as adhesion can be provided.

Next, the liquid crystal display element of the present invention will be described.
The liquid crystal display element of the present invention comprises the spacer formed as described above.
The structure of the liquid crystal display element is not particularly limited. For example, as shown in FIG. 2, a color filter layer and a spacer of the present invention are formed on a transparent substrate, and the liquid crystal display element 2 is disposed via the liquid crystal layer. A structure having two alignment films, opposing transparent electrodes, opposing transparent substrates, and the like can be given. As shown in FIG. 2, a protective film can be provided on the polarizing plate or the color filter layer as necessary.

  Further, as shown in FIG. 3, a color filter layer and a spacer of the present invention are formed on a transparent substrate, and are made to face a thin film transistor (TFT) array through an alignment film and a liquid crystal layer, thereby allowing a TN-TFT type. It can also be set as a liquid crystal display element. Also in this case, a protective film can be provided on the polarizing plate or the color filter layer as necessary.

The radiation-sensitive resin composition for spacer formation of the present invention has high resolution and high sensitivity even when exposed to radiation that does not substantially contain a wavelength of 350 nm or less, and has a pattern shape, compressive strength, rubbing resistance, It is possible to easily form spacers with excellent performance such as adhesion, and it is possible to lower the heating temperature after development at the time of spacer formation, and the resin substrate will not be yellowed or deformed .
The liquid crystal display element of the present invention includes a spacer having excellent performance such as pattern shape, compressive strength, rubbing resistance, and adhesion to a transparent substrate, and can exhibit high reliability over a long period of time.

Hereinafter, the embodiment of the present invention will be described more specifically with reference to examples.
Synthesis example 1
A flask equipped with a condenser and a stirrer was charged with 5 parts by weight of 2,2′-azobis (2,4-dimethylvaleronitrile) and 250 parts by weight of diethylene glycol methyl ethyl ether, followed by 20 parts by weight of styrene and 17 parts by weight of methacrylic acid. Part, 18 parts by weight of dicyclopentanyl methacrylate and 45 parts by weight of glycidyl methacrylate, and after purging with nitrogen, the temperature of the reaction solution was raised to 70 ° C. while gently stirring, and this temperature was maintained for 4 hours. By polymerization, a resin solution containing the [A] copolymer was obtained. The solid content concentration of this resin solution was 28.4% by weight, and the Mw of the obtained [A] copolymer was 16,000. This [A] copolymer is referred to as “copolymer (A-1)”.
Mw of the copolymer (A-1) and the copolymer (A-2) described below was measured using GPC (gel permeation chromatography) HLC-8020 (manufactured by Tosoh Corporation).

Synthesis example 2
A flask equipped with a condenser and a stirrer was charged with 4 parts by weight of 2,2′-azobis (2,4-dimethylvaleronitrile) and 250 parts by weight of diethylene glycol methyl ethyl ether, followed by 5 parts by weight of styrene and 16 parts by weight of methacrylic acid. , 34 parts by weight of dicyclopentanyl methacrylate and 40 parts by weight of glycidyl methacrylate were substituted with nitrogen, and further 5 parts by weight of 1,3-butadiene was added, and the temperature of the reaction solution was adjusted to 70 ° C. while gently stirring. And the temperature was maintained for 4 hours for polymerization to obtain a resin solution containing the [A] copolymer. The solid content concentration of this resin solution was 28.6% by weight, and Mw of the obtained [A] copolymer was 15,000. This [A] copolymer is referred to as “copolymer (A-2)”.

Example 1
(I) Preparation of radiation-sensitive resin composition (A) 100 parts by weight (solid content) of the resin solution obtained in Synthesis Example 1 as component (A-1) as component (A-1) and dipenta as component (B) 80 parts by weight of erythritol hexaacrylate (trade name KAYARAD DPHA, manufactured by Nippon Kayaku Co., Ltd.), 2,2′-bis (2,4-dichlorophenyl) -4,4 ′, 5,5′- as component [C] 10 parts by weight of tetraphenylbiimidazole, 15 parts by weight of 2-methyl [4- (methylthio) phenyl] -2-morpholino-1-propanone (trade name Irgacure 907, manufactured by Ciba Specialty Chemicals) as the [D] component [E] component, 4,4′-bis (dimethylamino) benzophenone 10 parts by weight, [F] component 2-mercaptobenzothiazole 5 parts, adhesion promoter 5 parts by weight of γ-glycidoxypropyltrimethoxysilane, 0.5 parts by weight of FTX-218 (trade name, manufactured by Neos Co., Ltd.) as a surfactant, and 0.5 parts by weight of 4-methoxyphenol as a storage stabilizer After mixing and dissolving in propylene glycol monomethyl ether acetate so that the solid content concentration was 30% by weight, the solution was filtered through a Millipore filter having a pore size of 0.5 μm to prepare a composition solution.

(II) Formation of Spacer The composition solution was applied on an alkali-free glass substrate using a spinner and then pre-baked on a hot plate at 90 ° C. for 3 minutes to form a film having a thickness of 6.0 μm.
Next, the obtained coating film was passed through a mask with a 10 μm square left pattern and irradiated with 10 ultraviolet rays having an intensity at 365 nm of 250 W / m ² and transmitted through an ultraviolet transmission filter “UV-35” manufactured by Toshiba Glass Co., Ltd. Exposure for 2 seconds. Thereafter, development was performed with a 0.05 wt% aqueous solution of potassium hydroxide at 25 ° C. for 60 seconds, followed by washing with pure water for 1 minute. Then, the spacer of the predetermined pattern was formed by post-baking for 120 minutes at 150 degreeC in oven.

(III) Evaluation of Resolution When the pattern was formed in (II) above, the case where the remaining pattern was resolved was evaluated as good (◯), and the case where the pattern was not resolved was evaluated as defective (×). The evaluation results are shown in Table 2.
(IV) Evaluation of sensitivity When the pattern obtained in (II) above has a remaining film ratio after development (film thickness after development × 100 / initial film thickness) of 90% or more (◯), less than 90% The case of was evaluated as defective (×). The evaluation results are shown in Table 2.

(V) Evaluation of pattern shape The cross-sectional shape of the pattern obtained in the above (II) was observed with a scanning electron microscope and evaluated according to which of A to D shown in FIG. At this time, when the pattern edge is forward tapered or vertical like A or B, the pattern shape as a spacer can be said to be good. On the other hand, as shown in C, when the sensitivity is insufficient, the remaining film rate is low, the cross-sectional dimension is smaller than A and B, and the cross-sectional shape is a semi-convex lens shape with a flat bottom surface, Since the pattern shape as a spacer is poor, and as shown in D, the pattern shape as a spacer is very high because the pattern may be peeled off during the subsequent rubbing process even when the cross-sectional shape is a reverse taper shape. Defective. The evaluation results are shown in Table 2.
(VI) Evaluation of compressive strength When a load of 10 mN was applied to the pattern obtained in (II) above using a micro compression tester (MCTM-200, manufactured by Shimadzu Corporation) with a flat indenter having a diameter of 50 μm. The amount of deformation of was measured at a measurement temperature of 23 ° C. When this value is 0.5 or less, it can be said that the compressive strength is good. The evaluation results are shown in Table 2.

(VII) Evaluation of rubbing resistance After applying AL3046 (trade name, manufactured by JSR Co., Ltd.) as a liquid crystal aligning agent to a substrate on which the pattern obtained in (II) is formed, using a printing machine for applying a liquid crystal alignment film. And dried at 180 ° C. for 1 hour to form a coating film of an orientation agent having a dry film thickness of 0.05 μm. Thereafter, a rubbing machine having a roll around which a polyamide cloth was wound was applied to this coating film, and the rubbing treatment was performed at a roll rotation speed of 500 rpm and a stage moving speed of 1 cm / sec. At this time, the presence or absence of pattern shaving or peeling was evaluated. The evaluation results are shown in Table 2.
(VIII) Evaluation of Adhesiveness A cured film was formed in the same manner as in (II) except that the mask of the remaining pattern was not used. Thereafter, the adhesive test of JIS K-5400 (1900) 8.5 was evaluated by the 8.5 / 2 cross-cut tape method. At this time, the number of remaining grids out of 100 grids is shown in Table 2.

Examples 2-14
Each composition solution was prepared and evaluated in the same manner as in Example 1 except that the components shown in Table 1-1 were used as the components [A] to [F]. The evaluation results are shown in Table 2.

Comparative Examples 1-9
Each composition solution was prepared and evaluated in the same manner as in Example 1 except that the components shown in Table 1-2 were used as the components [A] to [F]. The evaluation results are shown in Table 2.

In Table 1-1 and Table 1-2, each component other than the copolymer (A-1) and the copolymer (A-2) is as follows.
[B] Component B-1: Dipentaerythritol hexaacrylate [C] Component C-1: 2,2′-bis (2,4-dichlorophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole C -2: 2,2'-bis (2-chlorophenyl) -4,4 ', 5,5'-tetraphenylbiimidazole [D] component D-1: 2-methyl [4- (methylthio) phenyl] -2 -Morpholino-1-propanone D-2: 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1
[E] component E-1: 4,4'-bis (dimethylamino) benzophenone [F] component F-1: 2-mercaptobenzothiazole F-2: pentaerythritol tetra (mercaptoacetate)

It is a figure which illustrates the emission spectrum (thick line) of the mercury lamp which permeate | transmitted the ultraviolet transmission filter "UV-35", and the emission spectrum (thin line) of the mercury lamp which is not permeate | transmitted. It is a schematic diagram which shows an example of the structure of a liquid crystal display element. It is a schematic diagram which shows the other example of the structure of a liquid crystal display element. It is a schematic diagram which illustrates the cross-sectional shape of a spacer.

Claims (5)

[A] a copolymer of (a1) an unsaturated carboxylic acid and / or an unsaturated carboxylic acid anhydride, (a2) an epoxy group-containing unsaturated compound, and (a3) another unsaturated compound,
[B] polymerizable unsaturated compound,
[C] biimidazole compound,
A radiation-sensitive resin composition for spacer formation, comprising [D] a radiation-sensitive polymerization initiator having a carbonyl group, and [E] a compound having a dialkylamino group and / or [F] a thiol compound. . [C] The radiation-sensitive resin composition for forming a spacer according to claim 1, wherein the biimidazole compound is a compound represented by the following general formula (1) or general formula (2).

[Wherein, X represents a hydrogen atom, a halogen atom, a cyano group, an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 9 carbon atoms, A represents —COO—R (where R represents 1 to 4 is an alkyl group of 4 or an aryl group of 6 to 9 carbon atoms.), N is an integer of 1 to 3, and each m is an integer of 1 to 3. ]

(Wherein X ¹ , X ² and X ³ each independently represent a hydrogen atom, a halogen atom, a cyano group, an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 9 carbon atoms, provided that X ¹ , X ² and X ³ do not take a hydrogen atom at the same time.)   The spacer formed from the radiation sensitive resin composition for spacer formation of Claim 1 or Claim 2. A method for forming a spacer, comprising at least the following steps (a) to (d). (A) A step of forming a coating of the radiation-sensitive resin composition for forming a spacer according to claim 1 or 2 on a substrate.
(B) A step of exposing at least a part of the film to radiation that does not substantially contain a wavelength of less than 350 nm.
(C) A step of developing the film after exposure.
(D) A step of heating the film after development.   A liquid crystal display device comprising the spacer according to claim 3.

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