JP2006257220A - Copolymer, radiation-sensitive resin composition using this, spacer for liquid crystal display element, and liquid crystal display element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radiation-sensitive resin composition of high sensitivity and high resolution, and excellent in resilience, rubbing resistance, adhesivity to a transparent substrate and thermal resistance. <P>SOLUTION: This radiation-sensitive resin composition comprises a copolymer having a weight-average molecular weight of 2,000-100,000, obtained by copolymerizing an unsaturated carboxylic acid and/or carboxylic acid anhydride, an unsaturated compound expressed by formula (1) and other unsaturated compounds, a polymerizable unsaturated compound and a radiation-sensitive polymerization initiator. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention particularly relates to a copolymer used in a radiation-sensitive resin composition extremely suitable for forming a spacer in a liquid crystal display element, a radiation-sensitive resin composition using the copolymer, a spacer for a liquid crystal display element, a method for forming the same, and The present invention relates to a liquid crystal display element.

Conventionally, spacers such as glass beads and plastic beads having a predetermined particle diameter have been used for liquid crystal display elements in order to keep the distance (cell gap) between two substrates constant. However, since these spacers are randomly distributed on a transparent substrate such as a glass substrate, if there is a spacer in the pixel formation region, a reflection phenomenon of the spacer occurs or incident light is scattered and the liquid crystal display element As a result, there is a problem that the contrast decreases.
Therefore, in order to solve such a problem, a method of forming a spacer by photolithography has been adopted. In this method, a radiation-sensitive resin composition is applied on a substrate, exposed to, for example, 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 place other than the region, 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) from the viewpoint of increasing the area of the liquid crystal display element and improving productivity. However, since the conventional substrate size (about 680 × 880 mm) is smaller than the mask size, it was possible to cope with the batch exposure method. However, in the case of a large substrate, the mask size is about the same as this substrate size. It is almost impossible to manufacture, 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. .
Further, in the batch exposure method, an exposure amount of about 3,000 J / m ² is possible, but in the step exposure method, it is necessary to lower the exposure amount each time, and the conventional exposure method used for forming the spacer is used. In the radiation sensitive resin composition, it has been difficult to achieve a sufficient spacer shape and film thickness with an exposure amount of 1,200 J / m ² or less.

On the other hand, from the viewpoint of improving the throughput in the process of producing a liquid crystal display element, it is required to shorten the development time required for the conventional radiation-sensitive resin composition used for forming the spacer. For example, the optimal development time of the currently used spacer-forming radiation-sensitive resin composition is often 60 seconds, but it is more desirable that it be shorter than 40 seconds.
Similarly, from the viewpoint of improving throughput, a process technology “ODF (One Drop Fill) method” in which a liquid crystal material is applied to the surface of the glass substrate before bonding the glass substrates is introduced. The time required for manufacturing the liquid crystal display element can be greatly reduced. For example, in the case of a 30-inch liquid crystal display element, it takes about 5 days to fill the liquid crystal material with the conventional method, but about 2 hours is sufficient with the ODF method, and the throughput can be greatly improved. .
However, in the case of the ODF method, a step of pressure bonding the thin film transistor (TFT) array and the color filter is necessary at room temperature, and when the plastic deformation of the spacer due to the compressive load increases, the uniformity of the cell gap cannot be maintained, A gap is generated in the cell, causing display unevenness.

  Therefore, a spacer that is difficult to plastically deform and has a high recovery rate even when subjected to deformation due to a compressive load is required. For example, Patent Document 1 discloses that a monomer having a cyclic imide group, a (meth) acrylic acid monomer, and a hydroxyl group-containing monomer. A spacer composed of a polymer obtained by reacting an ethylenically unsaturated bond-containing isocyanate compound with a polymer and a photosensitive resin composition containing a thermally crosslinkable epoxy group-containing compound has been proposed. It is said to be sensitive and elastic. However, in this photosensitive resin composition, from the viewpoint of developability with respect to an alkaline aqueous solution, the amount of the thermally crosslinkable epoxy group-containing compound that contributes to the improvement in heat resistance is limited, so the heat resistance of the resulting spacer is not always satisfactory. There is a problem that you can not.

JP 2003-173025 A

The problems of the present invention are high sensitivity and high resolution, a short development time, and a sufficient spacer shape can be obtained even with an exposure amount of 1,200 J / m ² or less, elastic recovery, rubbing resistance, adhesion to a transparent substrate. Provided a specific copolymer capable of obtaining a radiation sensitive resin composition capable of forming a spacer for a liquid crystal display device having excellent properties such as heat resistance and heat resistance, and a radiation sensitive fiber resin composition using the same copolymer There is to do.

According to the present invention, the above problem is firstly
(A1) unsaturated carboxylic acid and / or unsaturated carboxylic acid anhydride,
(A2) a repeating compound derived from (a1) obtained by copolymerizing an unsaturated compound represented by the following formula (1), and (a3) another unsaturated compound other than the above components (a1) to (a2) The unit is 5 to 60% by weight, the repeating unit derived from (a2) is 1 to 60% by weight, the repeating unit derived from (a3) is 10 to 70% by weight [However, (a1) + (a2) + (a3 ) = 100 wt%] and is achieved by a copolymer having a polystyrene equivalent weight average molecular weight of 2,000 to 100,000.

(Wherein R ₁ is a hydrogen atom or a methyl group, R ₂ , R ₃ and R ₄ are each independently a hydrogen atom, a hydroxyl group, or an alkyl or alkoxy group having 1 to 6 carbon atoms, and n is It is an integer from 0 to 6.)

According to the present invention, the above problem is secondly,
[A] copolymer,
[B] A radiation-sensitive resin composition containing a polymerizable unsaturated compound and [C] a radiation-sensitive 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 spacer for a liquid crystal display element”) used for forming a spacer for a liquid crystal display element, comprising the radiation sensitive resin composition. The

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

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 element, comprising at least the following steps in the order described below.
(A) a step of forming a film of the radiation-sensitive resin composition for a spacer for a liquid crystal display element on a substrate;
(B) exposing at least a part of the coating;
(C) a step of developing the coated film after exposure, and (d) a step of heating the coated film after development.

According to the present invention, the above problem is sixth,
This is achieved by a liquid crystal display element comprising the liquid crystal display element spacer.

The radiation-sensitive resin composition of the present invention has high sensitivity and high resolution, and a sufficient pattern shape can be obtained even with an exposure amount of 1,200 J / m ² or less. Elastic recovery, rubbing resistance, adhesion to a transparent substrate It is possible to form spacers for liquid crystal display elements that are also excellent in heat resistance, etc., and at the time of spacer formation, it is possible to lower the post-baking temperature after development, which can cause yellowing and deformation of the resin substrate Absent.
In addition, the liquid crystal display element of the present invention includes a spacer having excellent performance such as pattern shape, elastic recovery, rubbing resistance, adhesion to a transparent substrate, and heat resistance, and has high reliability over a long period of time. Can be expressed.

Hereinafter, the present invention will be described in detail.
Radiation sensitive resin composition [A] copolymer:
The copolymer (A) used in the radiation-sensitive resin composition of the present invention comprises (a1) an unsaturated carboxylic acid and / or an unsaturated carboxylic acid anhydride, (a2) an unsaturated compound represented by the above formula (1). It is obtained by copolymerizing a compound and (a3) other unsaturated compounds other than the above components (a1) to (a2).

[A] Among the components constituting the copolymer, (a1) unsaturated carboxylic acid and / or unsaturated carboxylic acid anhydride (hereinafter collectively referred to as “(a1) unsaturated carboxylic acid compound”) ), For example,
Monocarboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, 2-acryloyloxyethyl succinic acid, 2-methacryloyloxyethyl succinic acid, 2-acryloyloxyethyl hexahydrophthalic acid, 2-methacryloyloxyethyl hexahydrophthalic acid;
Dicarboxylic acids such as maleic acid, fumaric acid, citraconic acid, mesaconic acid, itaconic acid;
The anhydride of the said dicarboxylic acid etc. can be mentioned.

Among these (a1) unsaturated carboxylic acid compounds, acrylic acid, methacrylic acid, 2 are preferable because of copolymerization reactivity, solubility of the resulting [A] copolymer in an alkaline developer, and easy availability. -Acryloyloxyethyl succinic acid, 2-methacryloyloxyethyl succinic acid, etc. are preferable.
[A] In the copolymer, (a1) unsaturated carboxylic acid compounds may be used alone or in admixture of two or more.

  [A] In the copolymer, the content of the repeating unit derived from the (a1) unsaturated carboxylic acid compound is 5 to 60% by weight, preferably 10 to 50% by weight, more preferably 15 to 40% by weight [ However, (a1) + (a2) + (a3) = 100 wt%, and so on. In this case, if the content of the repeating unit derived from the (a1) unsaturated carboxylic acid compound is less than 5% by weight, the solubility in an alkali developer tends to be reduced, whereas if it exceeds 60% by weight, There is a possibility that the solubility of the polymer in an alkaline developer becomes too large.

Moreover, (a2) As an unsaturated compound shown by the said Formula (1), for example,
Phenyl acrylate, phenyl methacrylate, benzyl acrylate, benzyl methacrylate, 2-methylphenyl acrylate, 2-methylphenyl methacrylate, 3-methylphenyl acrylate, 3-methylphenyl methacrylate, 4-methylphenyl acrylate, 4-methylphenyl methacrylate, 2- Hydroxyphenyl acrylate, 2-hydroxyphenyl methacrylate, 3-hydroxyphenyl acrylate, 3-hydroxyphenyl methacrylate, 4-hydroxyphenyl acrylate, 4-hydroxyphenyl methacrylate, 2,6-dimethyl-4-hydroxyphenyl acrylate, 2,6- Examples thereof include dimethyl-4-hydroxyphenyl methacrylate.

When the unsaturated carboxylic acid content in the copolymer is increased, the developability for an aqueous alkaline developer can be improved. However, in that case, the storage stability of the radiation-sensitive resin composition is reduced and the solution viscosity is increased. However, these (a2) can improve the developability with respect to the aqueous alkaline developer and can shorten the development time required for the conventional radiation-sensitive resin composition without impairing other performances. In particular, phenyl methacrylate, benzyl methacrylate, 4-hydroxyphenyl methacrylate and the like are preferable.
[A] In the copolymer, (a2) can be used alone or in admixture of two or more.

  [A] In the copolymer, the content of the repeating unit derived from (a2) is 1 to 60% by weight, preferably 3 to 50% by weight, and more preferably 5 to 40% by weight. In this case, if the content of the repeating unit derived from (a2) is less than 1% by weight, the solubility in the developer tends to decrease. On the other hand, if it exceeds 60% by weight, swelling during development and increase in the viscosity of the solution occur. Tend to generate.

Furthermore, as the (a3) other unsaturated compound, an epoxy group-containing unsaturated compound is first mentioned.
As an epoxy group-containing unsaturated compound, for example,
Acrylates such as glycidyl acrylate, 2-methylglycidyl acrylate, 4-hydroxybutyl acrylate glycidyl ether, 3,4-epoxybutyl acrylate, 6,7-epoxyheptyl acrylate, 3,4-epoxycyclohexyl acrylate (Cyclo) alkyl esters;
Methacrylic acid epoxy (cyclo) alkyl esters such as glycidyl methacrylate, 2-methylglycidyl methacrylate, 3,4-epoxybutyl methacrylate, 6,7-epoxyheptyl methacrylate, 3,4-epoxycyclohexyl methacrylate;
α-ethyl acrylate glycidyl, α-n-propyl acrylate glycidyl, α-n-butyl acrylate glycidyl, α-ethyl acrylate 6,7-epoxyheptyl, α-ethyl acrylate 3,4-epoxycyclohexyl, etc. Other α-alkyl acrylic acid epoxy (cyclo) alkyl esters;
Examples thereof include glycidyl ethers such as o-vinylbenzyl glycidyl ether, m-vinylbenzyl glycidyl ether, and p-vinylbenzyl glycidyl ether.

Among these epoxy group-containing unsaturated compounds, from the viewpoint of copolymerization reactivity and spacer strength, glycidyl methacrylate, 2-methylglycidyl methacrylate, 6,7-epoxyheptyl methacrylate, 4-hydroxybutyl acrylate glycidyl ether O-vinylbenzyl glycidyl ether, m-vinylbenzyl glycidyl ether, p-vinylbenzyl glycidyl ether, and the like are preferable.
[A] In the copolymer, (a3) the epoxy group-containing unsaturated compound can be used alone or in admixture of two or more.

In addition, as the other unsaturated compound (a3), in addition to the epoxy group-containing unsaturated compound, for example,
Alkyl acrylates such as methyl acrylate, n-propyl acrylate, i-propyl acrylate, n-butyl acrylate, sec-butyl acrylate, t-butyl acrylate;
Alkyl methacrylates such as methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, i-propyl methacrylate, n-butyl methacrylate, sec-butyl methacrylate, t-butyl methacrylate;

Cyclohexyl acrylate, 2-methylcyclohexyl acrylate, tricyclo [5.2.1.0 ^2,6 ] decanoyl acrylate, 2- (tricyclo [5.2.1.0 ^2,6 ] acrylate Acrylic alicyclic esters such as decan-8-yloxy) ethyl, isobornyl acrylate;
Cyclohexyl methacrylate, 2-methylcyclohexyl methacrylate, tricyclo [5.2.1.0 ^2,6 ] decanoyl methacrylate, 2- (tricyclo [5.2.1.0 ^2,6 ] methacrylate) Decane-8-yloxy) ethyl, methacrylic acid alicyclic esters such as isobornyl methacrylate;

Unsaturated dicarboxylic acid dialkyl esters such as diethyl maleate, diethyl fumarate, diethyl itaconate;

Acrylic esters having an oxygen-containing hetero 5-membered ring or an oxygen-containing hetero 6-membered ring such as tetrahydrofuran-2-yl acrylate, tetrahydropyran-2-yl acrylate, 2-methyltetrahydropyran-2-yl acrylate;
Methacrylate esters having an oxygen-containing hetero 5-membered ring or an oxygen-containing hetero 6-membered ring such as tetrahydrofuran-2-yl methacrylate, tetrahydropyran-2-yl methacrylate, 2-methyltetrahydropyran-2-yl methacrylate;

Vinyl aromatic compounds such as styrene, α-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene;
In addition to conjugated diene compounds such as 1,3-butadiene, isoprene and 2,3-dimethyl-1,3-butadiene,
Examples include acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, vinyl chloride, vinylidene chloride, and vinyl acetate.
Among the unsaturated compounds (a3) other than the epoxy group-containing unsaturated compound, from the viewpoint of copolymerization reactivity and solubility of the obtained [A] copolymer in an aqueous alkali solution, 2-methylcyclohexyl acrylate, Preferred are t-butyl methacrylate, tricyclo [5.2.1.0 ^2,6 ] decan-8-yl methacrylate, styrene, p-methoxystyrene, tetrahydrofuran-2-yl methacrylate, 1,3-butadiene and the like. .
[A] In the copolymer, (a3) other unsaturated compounds other than the epoxy group-containing unsaturated compound can be used alone or in admixture of two or more.

  [A] In the copolymer, the content of the repeating unit derived from the other unsaturated compound (a3) is 10 to 70% by weight, preferably 20 to 50% by weight, more preferably 30 to 50% by weight. It is. In this case, when the content of the repeating unit derived from (a3) another unsaturated compound is less than 10% by weight, the storage stability tends to be lowered. On the other hand, when the content exceeds 70% by weight, the alkali of the copolymer is reduced. There is a tendency for the solubility in a developing solution to fall.

  In the [A] copolymer, the (a3) other unsaturated compound is preferably an epoxy group-containing unsaturated compound. When using this epoxy group-containing unsaturated compound, the content of repeating units derived from the epoxy group-containing unsaturated compound in (a1) to (a3) is preferably 10 to 70% by weight, more preferably 15%. -60% by weight, particularly preferably 20-50% by weight. In this case, when the content of the repeating unit derived from the (a3) epoxy group-containing unsaturated compound is less than 10% by weight, the strength of the obtained spacer tends to decrease, whereas when it exceeds 70% by weight, the storage stability is increased. There is a tendency to decrease.

  [A] The copolymer may contain, for example, (a1) an unsaturated carboxylic acid compound, (a2) an unsaturated compound represented by the above formula (1), and (a3) another unsaturated compound in a suitable solvent. It can be produced by polymerizing in the presence of a radical polymerization initiator.

As the solvent used for the polymerization, for example,
Alcohols such as methanol, ethanol, n-propanol, i-propanol;
Ethers such as tetrahydrofuran and dioxane;
Ethylene glycol monoalkyl ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono-n-propyl ether, ethylene glycol mono-n-butyl ether;
Ethylene glycol monoalkyl ether acetates such as ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether, ethylene glycol mono-n-propyl ether acetate, ethylene glycol mono-n-butyl ether acetate;

Ethylene glycol monoalkyl ether propionates such as ethylene glycol monomethyl ether propionate, ethylene glycol monoethyl ether propionate, ethylene glycol mono-n-propyl ether propionate, ethylene glycol mono-n-butyl ether propionate ;
Diethylene glycol alkyl ethers such as diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol methyl ethyl ether;

Propylene glycol monoalkyl ethers such as propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono-n-propyl ether, propylene glycol mono-n-butyl ether;
Dipropylene glycol alkyl ethers such as dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether, dipropylene glycol methyl ethyl ether;

Propylene glycol monoalkyl ether acetates such as propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol mono-n-propyl ether acetate, propylene glycol mono-n-butyl ether acetate;
Propylene glycol monoalkyl ether propionates such as propylene glycol monomethyl ether propionate, propylene glycol monoethyl ether propionate, propylene glycol mono-n-propyl ether propionate, propylene glycol mono-n-butyl ether propionate ;

Aromatic hydrocarbons such as toluene and xylene;
Ketones such as methyl ethyl ketone, 2-pentanone, 3-pentanone, cyclohexanone, 4-hydroxy-4-methyl-2-pentanone;

Methyl 2-methoxypropionate, ethyl 2-methoxypropionate, n-propyl 2-methoxypropionate, n-butyl 2-methoxypropionate, methyl 2-ethoxypropionate, ethyl 2-ethoxypropionate, 2-ethoxypropion N-propyl acid, n-butyl 2-ethoxypropionate, methyl 2-n-propoxypropionate, ethyl 2-n-propoxypropionate, n-propyl 2-n-propoxypropionate, 2-n-propoxypropionic acid n-butyl, methyl 2-n-butoxypropionate, ethyl 2-n-butoxypropionate, n-propyl 2-n-butoxypropionate, n-butyl 2-n-butoxypropionate, methyl 3-methoxypropionate , Ethyl 3-methoxypropionate, 3-methoxy N-propyl propionate, n-butyl 3-methoxypropionate, methyl 3-ethoxypropionate, ethyl 3-ethoxypropionate, n-propyl 3-ethoxypropionate, n-butyl 3-ethoxypropionate, 3-n -Methyl propoxypropionate, ethyl 3-n-propoxypropionate, n-propyl 3-n-propoxypropionate, n-butyl 3-n-propoxypropionate, methyl 3-n-butoxypropionate, 3-n- Alkyl alkoxypropionates such as ethyl butoxypropionate, n-propyl 3-n-butoxypropionate, n-butyl 3-n-butoxypropionate,

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 2-hydroxy-2-methylpropionate, ethyl 2-hydroxy-2-methylpropionate, methyl 3-hydroxypropionate, ethyl 3-hydroxypropionate, n-propyl 3-hydroxypropionate, 3-hydroxy N-butyl propionate, 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, Other esters such as n-butyl n-butoxyacetate can be mentioned.

Of these solvents, diethylene glycol alkyl ethers, propylene glycol monoalkyl ether acetates, alkyl alkoxypropionates and the like are preferable.
The said solvent can be used individually or in mixture of 2 or more types.
The usage-amount of the above solvent is 150-450 weight part with respect to 100 weight part of total amounts of (a1)-(a3) component, Preferably it is 200-400 weight part.

The radical polymerization initiator is not particularly limited, and examples thereof include 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), Azo compounds such as 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile); benzoyl peroxide, lauroyl peroxide, t-butylperoxypivalate, 1,1-bis (t-butylperoxy) cyclohexane, etc. And organic peroxides such as hydrogen peroxide.
Moreover, when using a peroxide as a radical polymerization initiator, it is good also as a redox type initiator using it together with a reducing agent.
These radical polymerization initiators can be used alone or in admixture of two or more.

  The usage-amount of a radical polymerization initiator is 1-20 weight part with respect to 100 weight part of total amounts of (a1)-(a3) component, Preferably it is 3-15 weight part.

In addition, in the radical polymerization, a surfactant, a continuous transfer agent, and the like can be used in combination.
The radical polymerization conditions are such that the temperature is 50 to 110 ° C., preferably 60 to 100 ° C., and the polymerization time is 180 to 480 minutes, preferably about 240 to 420 minutes.

[A] The polystyrene-reduced weight average molecular weight (hereinafter referred to as “Mw”) of the copolymer by gel permeation chromatography (GPC) is 2,000 to 100,000, preferably 5,000 to 50,000. In this case, if the Mw is less than 2,000, there is a possibility that the alkali developability, the remaining film ratio, etc. of the resulting film may be reduced, and the pattern shape, heat resistance, etc. may be impaired. If it exceeds 1, the resolution may be reduced, or the pattern shape may be impaired.
[A] The molecular weight of the copolymer depends on the amount of solvent, the amount of radical polymerization initiator, the polymerization time, the polymerization temperature, and the use of a chain transfer agent with respect to the total amount of the copolymers (a1) to (a3). Can be adjusted.

  [A] The copolymer has a carboxyl group and / or a carboxylic anhydride group, and can have an appropriate solubility in an alkali developer. Moreover, (a2) By having the unsaturated compound shown by Formula (1), the solubility with respect to an alkali developing solution can be improved, without reducing storage stability. Furthermore, when the [A] copolymer has a carboxyl group and / or a carboxylic anhydride group, an epoxy group and a polymerizable unsaturated bond, it can be easily cured by heating without using a special curing agent. It can be done. Therefore, the radiation-sensitive resin composition of the present invention containing the [A] copolymer can easily form a spacer having a predetermined shape without developing residue and film loss during development.

  The radiation sensitive resin composition of the present invention is a radiation sensitive resin composition containing the following [B] polymerizable unsaturated compound and [C] radiation sensitive polymerization initiator in the above [A] copolymer. is there.

[B] Polymerizable unsaturated compound:
[B] The polymerizable unsaturated compound comprises an unsaturated compound that is polymerized by exposure to radiation in the presence of a radiation-sensitive polymerization initiator.
Such a [B] polymerizable unsaturated compound is not particularly limited. For example, monofunctional, bifunctional, or trifunctional or higher (meth) acrylic esters have good copolymerizability. From the viewpoint of improving the strength of the obtained spacer.

  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, 3 -Methoxybutyl acrylate, 3-methoxybutyl methacrylate, (2-acryloyloxyethyl) (2-hydroxypropyl) phthalate, (2-methacryloyloxyethyl) (2-hydroxypropyl) phthalate, etc. As a trade name, for example, Aronix M-101, M-111, M-114 (above, manufactured by Toa Gosei Co., Ltd.); KAYARAD TC-110S, T C-120S (Nippon Kayaku Co., Ltd.); Biscote 158, 2311 (Osaka Organic Chemical Co., Ltd.) can be used.

  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, 1,6 -Hexanediol diacrylate, 1,6-hexanediol dimethacrylate, 1,9-nonanediol diacrylate, 1,9-nonanediol dimethacrylate, bisphenoxyethanol full orange acrylate, bisphenoxyethanol full orange methacrylate, polyester both ends (meta ) Acrylic modification, Polypropylene glycol both ends (meth) acrylic modification, Polytetramethylene Glycol In addition, as a commercial product, for example, Aronix M-210, M-240, M-6200 (above, manufactured by Toa Gosei Co., Ltd.), KAYARAD HDDA, HX-220, R-604 (above, manufactured by Nippon Kayaku Co., Ltd.), Biscoat 260, 312, 335HP (above, manufactured by Osaka Organic Chemical Industry Co., Ltd.), U-108A, U -200AX, UA-4100, UA-4400, UA-340P, UA-2235PE, UA-160TM, UA-6100, U-2PPA200A (above, manufactured by Shin-Nakamura Chemical Co., Ltd.), etc., UN-9000PEP, UN- 9200A, UN-7600, UN-5200, UN-1003, UN-1255, UN-6060PTM, UN-6060P, SH-50 B (above, Negami Chemical Industry Co., Ltd.), and the like.

  Further, the trifunctional or higher functional (meth) acrylic acid esters include, for example, 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, and 9 functional As the above (meth) acrylic acid esters, linear alkylene groups and alicyclic rings A compound having a structure and having two or more isocyanate groups, one or more hydroxyl groups in the molecule, and having three, four or five acryloyloxy groups and / or methacryloyloxy groups The polyfunctional urethane acrylate type compound obtained by making it react with a compound can be mentioned.

  Commercially available products of tri- or higher functional (meth) acrylic acid esters are trade names, for example, Aronix M-309, M-400, M-405, M-450, M-7100, M -8030, M-8060, TO-1450 (above, manufactured by Toa Gosei Co., Ltd.), KAYARAD TMPTA, DPHA, DPCA-20, DPCA-30, DPCA-60, DPCA-120 (above) , Nippon Kayaku Co., Ltd.), Biscoat 295, 300, 360, GPT, 3PA, 400 (above, Osaka Organic Chemical Co., Ltd.) and polyfunctional urethane acrylate compounds As commercial products, New Frontier R-1150 (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), KAYARAD DPHA-40H (manufactured by Nippon Kayaku Co., Ltd.), U 4HA, U-6HA, U-6LPA, U-15HA, UA-32P, U-324A, U-4H, U-6H (manufactured by Shin-Nakamura Chemical Co., Ltd.), UN-9000H, UN-3320HA, And UN-3320HB, UN-3320HC, UN-901T, UN-1200TPK (manufactured by Negami Industrial Co., Ltd.).

Of these monofunctional, bifunctional, or trifunctional or higher (meth) acrylic acid esters, bifunctional or higher functional (meth) acrylic acid esters are more preferable, and particularly, polyester both-end acrylic modification, trimethylolpropane triacrylate. Pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, and a commercial product containing a polyfunctional urethane acrylate compound are preferred.
The monofunctional, bifunctional, or trifunctional or higher (meth) acrylic acid esters 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 [B] polymerizable unsaturated compound used is preferably 1 to 120 parts by weight, more preferably 3 to 100 parts by weight of the [A] copolymer. 100 parts by weight. In this case, if the amount of the [B] polymerizable unsaturated compound used is less than 1 part by weight, there is a risk of developing residue during development, whereas if it exceeds 120 parts by weight, the adhesion of the resulting spacer tends to decrease. There is.

[C] Radiation sensitive polymerization initiator:
[C] Radiation sensitive polymerization initiator generates [B] active species capable of initiating polymerization of polymerizable unsaturated compounds upon exposure to radiation such as visible light, ultraviolet light, far ultraviolet light, charged particle beam, and X-ray. It consists of ingredients that
As such [C] 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, the [C] radiation sensitive polymerization initiator is an O-acyl oxime photopolymerization initiator other than the O-acyl oxime polymerization initiator (I) (hereinafter referred to as “O-acyl oxime polymerization”). One or more initiators (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 obtain a pacer with sufficient sensitivity and good adhesion even at an exposure amount of 1,200 J / m ² or less.

In the radiation sensitive resin composition of the present invention, the amount of the O-acyloxime polymerization initiator (I) used is preferably 5 to 30 parts by weight with respect to 100 parts by weight of the [B] polymerizable unsaturated compound, More preferably, it is 5-20 weight part. In this case, if the amount of the O-acyloxime type polymerization initiator (I) used is less than 5 parts by weight, the remaining film ratio during development tends to decrease. There exists a tendency for the solubility with respect to an alkali developing solution to fall.
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, the sensitivity, spacer shape and compressive strength can be further improved by using an acetophenone compound in combination.

  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 , 2,2'-bis (2-chlorophenyl) -4,4 ', 5,5'-tetraphenyl-1,2'-biimidazole are preferred.
In the present invention, it is possible to further improve sensitivity, resolution and adhesion by using a biimidazole compound in combination.

When a biimidazole compound is used in combination, an aliphatic or aromatic compound having a dialkylamino group (hereinafter referred to as “amino sensitizer”) can be added to sensitize it. .
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. In addition, 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 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 80 parts by weight or less, more preferably 70 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 80 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 tends to be reduced. There is a tendency to be damaged.
Moreover, when using a biimidazole type compound and a thiol type compound together, the addition amount of a thiol type compound becomes like this. Preferably it is 0.1-50 weight part with respect to 100 weight part of biimidazole type compounds, More preferably, it is 1- 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 shape of the spacer tends to be reduced or the film tends to be reduced. On the other hand, if the amount exceeds 50 parts by weight, the resulting spacer There is a tendency that the shape of is damaged.

  However, in this invention, only [C] 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.

Additive:
In the radiation-sensitive resin composition of the present invention, a surfactant, an adhesion assistant, a storage stabilizer, a heat resistance, in addition to the above components, if necessary, within a range that does not impair the intended effect of the present invention. Additives such as property improvers can also be blended.

The surfactant is a component having an effect of improving applicability, and a fluorine surfactant and a silicone surfactant are preferable.
The fluorine-based surfactant is preferably a compound having a fluoroalkyl group or a fluoroalkylene group in at least one of the terminal, main chain and side chain. Specific examples thereof include 1,1,2,2- Tetrafluorooctyl (1,1,2,2-tetrafluoro-n-propyl) ether, 1,1,2,2-tetrafluoro-n-octyl (n-hexyl) ether, octaethylene glycol di (1,1 , 2,2-tetrafluoro-n-butyl) ether, hexaethylene glycol (1,1,2,2,3,3-hexafluoro-n-pentyl) ether, octapropylene glycol di (1,1,2, 2-tetrafluoro-n-butyl) ether, hexapropylene glycol di (1,1,2,2,3,3-hexafluoro-n- Nethyl) ether, 1,1,2,2,3,3-hexafluoro-n-decane, 1,1,2,2,8,8,9,9,10,10-decafluoro-n-dodecane, Sodium perfluoro-n-dodecylsulfonate, sodium fluoroalkylbenzenesulfonates, sodium fluoroalkylphosphonates, sodium fluoroalkylcarboxylates, fluoroalkylpolyoxyethylene ethers, diglycerin tetrakis (fluoroalkylpolyoxyethylene ether) ), Fluoroalkyl ammonium iodides, fluoroalkyl betaines, fluoroalkyl polyoxyethylene ethers, perfluoroalkyl polyoxyethanols, perfluoroalkyl alkoxylates, fluorine alkyl esters It can be mentioned.

  Moreover, as a commercial item of a fluorine-type surfactant, it is a brand name, for example, BM-1000, the same -1100 (above, the product made from BM CHEMIE), MegaFuck F142D, the same F172, the same F173, the same F183, the same F178. F191, F471, F476 (above, manufactured by Dainippon Ink & Chemicals, Inc.), Florard FC 170C, FC-171, FC-430, FC-431 (above, manufactured by Sumitomo 3M Limited) ), Surflon S-112, S-113, S-131, S-141, S-145, S-382, SC-101, SC-102, SC-103, SC-103 104, SC-105, SC-106 (above, manufactured by Asahi Glass Co., Ltd.), F-top EF301, EF303, EF352 (above, manufactured by Shin-Akita Kasei Co., Ltd.), lid Agent FT-100, FT-110, FT-140A, FT-150, FT-250, FT-251, FTX-251, FTX-218, FT-300, FT-310, FT-400S (above, manufactured by Neos Co., Ltd.).

  As said silicone type surfactant, it is a commercial item and is a brand name, for example, Toray silicone DC3PA, same DC7PA, same SH11PA, same SH21PA, same SH28PA, same SH29PA, same SH30PA, same SH-190, same SH-193 SZ-6032, SF-8428, DC-57, DC-190 (manufactured by Toray Dow Corning Silicone Co., Ltd.), TSF-4440, -4300, -4445, -4446 -4460, -4442 (above, manufactured by GE Toshiba Silicone Co., Ltd.).

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; For example, KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.), Polyflow No. 57, no. 95 (manufactured by Kyoeisha Chemical Co., Ltd.).
The said surfactant can be used individually or in mixture of 2 or more types.
The compounding amount of the surfactant is preferably 5 parts by weight or less, and more preferably 2 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 surfactant exceeds 5 parts by weight, there is a tendency that film roughening is likely to occur during coating.

The adhesion assistant is a component having an action of further improving the adhesion between the spacer and the substrate, and a functional silane coupling agent is preferable.
Examples of the functional silane coupling agent include compounds having a reactive functional group such as a carboxyl group, a methacryloyl group, a vinyl group, an isocyanate group, and an epoxy group, and more specifically, trimethoxysilyl. Benzoic acid, γ-methacryloyloxypropyltrimethoxysilane, vinyltriacetoxysilane, vinyltrimethoxysilane, γ-isocyanatopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ) Ethyltrimethoxysilane and the like.
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 [A] copolymer. 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.

Examples of the storage stabilizer include sulfur, quinones, hydroquinones, polyoxy compounds, amines, nitronitroso compounds, and more specifically, 4-methoxyphenol, N-nitroso-N-phenyl. Examples include hydroxylamine aluminum.
These storage stabilizers can be used alone or in admixture of two or more.
The amount of the storage stabilizer is preferably 3 parts by weight or less, more preferably 0.001 to 0.5 parts by weight with respect to 100 parts by weight of the [A] copolymer. In this case, if the amount of the storage stabilizer exceeds 3 parts by weight, the sensitivity may decrease and the pattern shape may be impaired.

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 particularly 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 (ethoxy). Methyl) melamine, N, N, N, N, N, N-hexa (n-propoxymethyl) melamine, N, N, N, N, N, N-hexa (i-propoxymethyl) melamine, N, N, Examples thereof include N, N, N, N-hexa (n-butoxymethyl) melamine, N, N, N, N, N, N-hexa (t-butoxymethyl) melamine and the like.
Among these N- (alkoxymethyl) melamine compounds, N, N, N, N, N, N-hexa (methoxymethyl) melamine is particularly preferable, and a commercial product thereof is, for example, Nicalac N- 2702, MW-30M (manufactured by Sanwa Chemical Co., Ltd.) and the like.

  Examples of the compound having two or more epoxy groups include ethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, and polypropylene glycol diester. Glycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerin diglycidyl ether, glycerin triglycidyl ether, trimethylolpropane triglycidyl ether, hydrogenated bisphenol A diglycidyl ether, bisphenol A diglycidyl ether , Ortho-cresol novolac type epoxy resin and commercial products Thus, for example, Epolite 40E, 100E, 200E, 70P, 200P, 400P, 1500NP, 1600, 80MF, 100MF, 3002, and 4000 (above Kyoeisha Chemical Co., Ltd.), EOCN102 103S, 104S, 1020, 1025, 1027 (manufactured by Nippon Kayaku Co., Ltd.), Epicoat 180S (manufactured by Japan Epoxy Resin Co., Ltd.), and the like.

The above heat resistance improvers can be used alone or in admixture of two or more.
The blending amount of the heat resistance improver is preferably 30 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 heat resistance improver exceeds 30 parts by weight, the storage stability of the radiation-sensitive resin composition tends to decrease.

The radiation-sensitive resin composition of the present invention is preferably used as a composition solution dissolved in an appropriate solvent.
As the solvent, those components that uniformly dissolve each component constituting the radiation-sensitive resin composition, do not react with each component, and have moderate volatility are used. Alcohols, ethylene glycol monoalkyl ether acetates, diethylene glycol monoalkyl ether acetates, diethylene glycol alkyl ethers, propylene glycol monoalkyl ether acetates, alkyl alkoxypropionates In particular, benzyl alcohol, 2-phenylethanol, 3-phenyl-1-propanol, ethylene glycol mono-n-butyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol dimethyl ester Ether, diethylene glycol diethyl ether, diethylene glycol ethyl methyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate are preferred.
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 above 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. , Di-n-hexyl ether, acetonyl acetone, isophorone, caproic acid, caprylic acid, 1-octanol, 1-nonanol, benzyl alcohol, benzyl acetate, ethyl benzoate, diethyl oxalate, diethyl maleate, γ-butyrolactone, Examples thereof include ethylene carbonate, propylene carbonate, and ethylene glycol monophenyl ether acetate.
These high boiling point solvents can be used alone or in admixture of two or more.
The amount of the high-boiling solvent used is preferably 50% by weight or less, more preferably 30% by weight or less in the total solvent.
Moreover, the usage-amount of the above solvent is the quantity from which the solid content concentration of the radiation sensitive resin composition of this invention will be 15 to 45 weight% normally, Preferably it is about 20 to 40 weight%.
In addition, the composition solution prepared as described above can be used after being filtered using a Millipore filter having a pore diameter of about 0.5 μm.

  Especially the radiation sensitive resin composition of this invention can be used very suitably for formation of the spacer for liquid crystal display elements.

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 formation of the spacer of the present invention includes at least the following steps in the order described below.
(A) forming a film of the radiation sensitive resin composition of the present invention on a substrate;
(B) exposing at least a part of the coating;
(C) a step of developing the coated film after exposure, and (d) a step of heating the coated 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, and a radiation-sensitive resin composition is applied onto the transparent conductive film, preferably as a composition solution, 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 the transparent conductive film provided on one surface of the transparent substrate, a NESA film (registered trademark of PPG, USA) made of tin oxide (SnO2), an ITO film made of indium oxide-tin oxide (In2O3-SnO2), or the like 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. However, the spin coating method and the slit die coating method are particularly preferable.
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. In this case, when exposing a part of the film, the exposure is usually performed through a photomask having a predetermined pattern.
As the radiation used for the exposure, for example, visible light, ultraviolet light, far ultraviolet light, electron beam, X-ray and the like can be used. However, radiation having a wavelength in the range of 190 to 450 nm is preferable, and particularly radiation containing 365 nm ultraviolet light. Is preferred.
The exposure amount 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 3,000 J / m ² .

(C) Process:
Subsequently, the exposed film is developed to remove unnecessary portions and form a predetermined pattern.
As the developer used for development, an alkali developer is preferable, and examples thereof include inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, and ammonia; ethylamine, n Aliphatic primary amines such as propylamine; Aliphatic secondary amines such as diethylamine and di-n-propylamine; Aliphatic tertiary amines such as trimethylamine, methyldiethylamine, dimethylethylamine and triethylamine; pyrrole and piperidine , N-methylpiperidine, N-methylpyrrolidine, 1,8-diazabicyclo [5.4.0] -7-undecene, 1,5-diazabicyclo [4.3.0] -5-nonene 3 Secondary amines: aromatics such as pyridine, collidine, lutidine, quinoline 3 Examples include quaternary amines; alkanolamines such as ethanoldimethylamine, methyldiethanolamine, and triethanolamine; and aqueous solutions of alkaline compounds such as quaternary ammonium salts such as tetramethylammonium hydroxide and tetraethylammonium hydroxide.
Further, an appropriate amount of a water-soluble organic solvent such as methanol or ethanol or a surfactant can be added to the aqueous solution of the alkaline compound.
As a developing method, any of a liquid piling method, a dipping method, a shower method and the like may be used, and the developing time is usually about 10 to 180 seconds.
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.

(2) Process:
Next, the obtained pattern is heated at a predetermined temperature, for example, 150 to 250 ° 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 an oven. A predetermined spacer can be obtained by heating (post-baking).

Liquid crystal display element The liquid crystal display element of the present invention comprises the spacer of the present invention formed as described above.
The structure of the liquid crystal element of the present invention is not particularly limited. For example, as shown in FIG. 1, a color filter layer and a spacer are formed on a transparent substrate, and the liquid crystal 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. Moreover, as shown in FIG. 1, you may form a protective film on a polarizing plate or a color filter layer as needed.

  In addition, as shown in FIG. 2, a color filter layer and a spacer are formed on a transparent substrate, and are opposed to a thin film transistor (TFT) array through an alignment film and a liquid crystal layer, whereby a TN-TFT type liquid crystal display. It can also be an element. Also in this case, a protective film may be formed on the polarizing plate or the color filter layer as necessary.

  Hereinafter, the embodiment of the present invention will be described more specifically with reference to examples. Here, parts and% are based on weight.

Synthesis example 1
A flask equipped with a condenser and a stirrer was charged with 5 parts of 2,2′-azobis (isobutyronitrile) and 250 parts of diethylene glycol methyl ethyl ether, followed by 10 parts of methacrylic acid and 30 parts of 2-methacryloyloxyethyl succinic acid. 1 part, 25 parts of n-butyl methacrylate and 30 parts of benzyl methacrylate, and after nitrogen substitution, further 5 parts by weight of 1,3-butadiene were added and the temperature of the solution was raised to 90 ° C. while gently stirring. The polymerization was carried out while maintaining this temperature for 5 hours to obtain an [A] copolymer solution having a solid content concentration of 28.0%. This is referred to as [A-1] polymer.
With respect to the obtained [A-1] polymer, Mw was measured by GPC (gel permeation chromatography) HLC-8020 (trade name, manufactured by Tosoh Corporation) and found to be 10,000.

Synthesis example 2
A flask equipped with a condenser and a stirrer was charged with 5 parts of 2,2′-azobis (isobutyronitrile) and 250 parts of diethylene glycol methyl ethyl ether, followed by 10 parts of methacrylic acid and 30 parts of 2-methacryloyloxyethyl succinic acid. Parts, 25 parts of n-butyl methacrylate and 30 parts of 4-hydroxyphenyl methacrylate, and after replacing with nitrogen, further 5 parts of 1,3-butadiene were added and the temperature of the solution was raised to 90 ° C. while gently stirring. By raising the temperature and carrying out polymerization for 5 hours, an [A] copolymer solution having a solid content concentration of 27.9% was obtained. This is designated as [A-2] polymer.
With respect to the obtained [A-2] polymer, Mw was measured by GPC to be 9,800.

Synthesis example 3
A flask equipped with a condenser and a stirrer was charged with 7 parts of 2,2′-azobis (2,4-dimethylvaleronitrile) and 250 parts of diethylene glycol methyl ethyl ether, followed by 18 parts of methacrylic acid and 27 parts of glycidyl methacrylate. , Tricyclomethacrylic acid [5.2.1.0 ^2,6 ] decan-8-yl 20 parts, 4-hydroxyphenyl methacrylate 30 parts, and after nitrogen substitution, further 5 parts 1,3-butadiene While gently stirring, the temperature of the solution was raised to 70 ° C., and this temperature was maintained for 4 hours for polymerization to obtain an [A] copolymer solution having a solid content concentration of 28.5%. This is referred to as [A-3] polymer.
With respect to the obtained [A-3] polymer, Mw was measured by GPC and found to be 10,000.

Synthesis example 4
A flask equipped with a condenser and a stirrer was charged with 5 parts of 2,2′-azobis (isobutyronitrile) and 250 parts of diethylene glycol methyl ethyl ether, followed by 10 parts of methacrylic acid and 30 parts of 2-methacryloyloxyethyl succinic acid. Parts, 25 parts by weight of n-butyl methacrylate, 25 parts by weight of tricyclo [5.2.1.0 ^2,6 ] decane-8-yl, and after substituting with nitrogen, further 5 parts by weight of 1,3-butadiene Was added, and the temperature of the solution was raised to 90 ° C. while polymerizing while maintaining this temperature for 5 hours to obtain an [A] copolymer solution having a solid content concentration of 28.0%. [A-4] A polymer.
With respect to the obtained [A-4] polymer, Mw was measured by GPC to be 11,000.

Example 1
Preparation of Composition Solution As component [A], 100 parts of polymer solution (A-1) obtained in Synthesis Example 1 as polymer (A-1) and dipentaerystol hexaacrylate (product) as component [B] Name KAYARAD DPHA, manufactured by Nippon Kayaku Co., Ltd.) 80 parts, [C] component, 1- [9-ethyl-6- (2-methylbenzoyl) -9. H. -Carbazol-3-yl] -ethane-1-one oxime-O-acetate (trade name CGI-242, manufactured by Ciba Specialty Chemicals), γ-glycidoxypropyltrimethoxysilane as an adhesion assistant 5 parts, 0.5 parts FTX-218 (trade name, manufactured by Neos Co., Ltd.) as a surfactant and 0.5 parts 4-methoxyphenol as a storage stabilizer are mixed to a solid content concentration of 30%. After being dissolved in propylene glycol monomethyl ether acetate, it was filtered through a Millipore filter having a pore size of 0.5 μm to prepare a composition solution.

Formation of Spacer The above composition solution was applied on a non-alkali glass substrate using a spinner and then pre-baked on an 80 ° C. hot plate for 3 minutes to form a film having a thickness of 4.0 μm.
Subsequently, the obtained coating film was exposed to ultraviolet rays having an intensity of 365 W / m ² at 365 nm for 10 seconds through a photomask having a remaining pattern of 10 μm square. Then, after developing for a predetermined time with a 0.05 wt% aqueous solution of potassium hydroxide at 25 ° C., it was washed with pure water for 1 minute, and further heated in an oven at 220 ° C. for 60 minutes to form a spacer.

Next, various evaluations were performed in the following manner. The evaluation results are shown in Table 3.
(1) Evaluation of development time A spacer was formed in the same manner as in the formation of the spacer except that the development time was variable. At this time, the development time was set to 25, 30, 35, 40, 45, 50, and 60 seconds, and the residue in the unexposed area was observed with an optical microscope at each development time. Even when the development time is 40 seconds or less, if it is confirmed that there is no residue in the unexposed area, it can be said that the development time has been shortened.

(2) Evaluation of sensitivity When the spacer is formed in the same manner as the formation of the spacer except that the exposure amount is variable, the residual film ratio after development (film thickness after development × 100 / initial film thickness. Below) Similarly, the exposure amount at which 90% or more is defined as sensitivity. When this exposure amount is 1,200 J / m ² or less, it can be said that the sensitivity is good.

(3) Evaluation of resolution The minimum resolution that can be resolved by the exposure amount at which the residual film ratio after development is 90% or more when the spacer is formed in the same manner as the formation of the spacer except that the exposure amount is variable. The pattern size was evaluated.

(4) Evaluation of cross-sectional shape The cross-sectional shape of the obtained spacer was observed with a scanning electron microscope and evaluated according to which of A to C shown in FIG. At this time, when the pattern edge is forward tapered or vertical like A or B, it can be said that the cross-sectional shape is good. On the other hand, as shown in C, there is a risk that the pattern may be peeled off during the subsequent rubbing process even in the case of an inversely tapered shape (in the cross-sectional shape, an inverted triangle shape in which the side of the film surface is longer than the side on the substrate side). Since it became very large, the cross-sectional shape was regarded as defective.

(5) Evaluation of elastic recovery rate About the obtained spacer, using a micro compression tester (trade name MCTM-200, manufactured by Shimadzu Corporation), a flat indenter with a diameter of 50 μm was used to adjust both the loading speed and the 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. 4, 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

(6) Evaluation of rubbing resistance AL3046 (trade name, manufactured by JSR Co., Ltd.) as a liquid crystal aligning agent was applied to a substrate on which a spacer was formed by a printing machine for applying a liquid crystal alignment film, and then dried at 180 ° C. for 1 hour. A film of a liquid crystal aligning agent having a thickness of 0.05 μm was formed.
Thereafter, the coating film was subjected to a rubbing treatment with a rubbing machine having a roll around which a polyamide cloth was wound, with 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.

(7) Evaluation of adhesion After forming a cured film in the same manner as the formation of the spacer except that no photomask was used, among the adhesion tests of JIS K-5400 (1900) 8.5, It 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.

(8) Evaluation of heat resistance A cured film was formed in the same manner as the spacer formation except that no photomask was used, and then heated in an oven at 240 ° C. for 60 minutes, and the film thickness before and after heating was measured. Then, the remaining film ratio (film thickness after heating × 100 / initial film thickness) was evaluated.

Examples 2-18, Comparative Examples 1-6
In Example 1, each component shown in Table 1 was used as an adhesion assistant, 5 parts of γ-glycidoxypropyltrimethoxysilane, as a surfactant, 0.5 part of FTX-218, and as a storage stabilizer, 4 parts. -It mixed with 0.5 parts of methoxyphenol, dissolved in propylene glycol monomethyl ether acetate so that the solid content concentration was 30%, and then filtered through a Millipore filter having a pore size of 0.5 µm to prepare a composition solution. Thereafter, spacers were formed in the same manner as in Example 1 and evaluated in the same manner as in Example 1. The evaluation results are shown in Table 2.

In Table 1, each component other than the polymer is as follows.
[B] component B-1: dipentaerystol hexaacrylate (trade name KAYARAD DPHA)
B-2: A commercial product containing a polyfunctional urethane acrylate compound (trade name KAYARAD DPHA-40H)

[C] component C-1: 1- [9-ethyl-6- (2-methylbenzoyl) -9. H. -Carbazol-3-yl] -ethane-1-one oxime-O-acetate (trade name CGI-242, manufactured by Ciba Specialty Chemicals)
D-1: 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one (trade name Irgacure 907, manufactured by Ciba Specialty Chemicals)
D-2: 2- (4-Methylbenzoyl) -2- (dimethylamino) -1- (4-morpholinophenyl) -butan-1-one E-1: 2,2′-bis (2,4- Dichlorophenyl) -4,4 ′, 5,5′-tetraphenyl-1,2′-biimidazole E-2: 2,2′-bis (2-chlorophenyl) -4,4 ′, 5,5′-tetra Phenyl-1,2'-biimidazole,
E-3: 4,4′-bis (diethylamino) benzophenone E-4: 2-mercaptobenzothiazole

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. 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 (6)

(A1) unsaturated carboxylic acid and / or unsaturated carboxylic acid anhydride,
(A2) a repeating compound derived from (a1) obtained by copolymerizing an unsaturated compound represented by the following formula (1), and (a3) another unsaturated compound other than the above components (a1) to (a2) The unit is 5 to 60% by weight, the repeating unit derived from (a2) is 1 to 60% by weight, the repeating unit derived from (a3) is 10 to 70% by weight [However, (a1) + (a2) + (a3 ) = 100 wt%], and a copolymer having a polystyrene-equivalent weight average molecular weight of 2,000 to 100,000.

(Wherein R ₁ is a hydrogen atom or a methyl group, R ₂ , R ₃ and R ₄ are each independently a hydrogen atom, a hydroxyl group, or an alkyl or alkoxy group having 1 to 6 carbon atoms, and n is It is an integer from 0 to 6.) [A] the copolymer according to claim 1,
[B] A radiation-sensitive resin composition comprising a polymerizable unsaturated compound, and [C] a radiation-sensitive polymerization initiator.   The radiation-sensitive resin composition according to claim 2, which is used for forming a spacer for a liquid crystal display element. A method for forming a spacer for a liquid crystal display element, comprising the following steps in the order described below.
(1) The process of forming the coating film of the radiation sensitive composition in any one of Claims 2-3 on a board | substrate,
(2) A step of irradiating at least a part of the coating film with radiation,
(3) Development step, and (4) Heating step.   The spacer for liquid crystal display elements formed by the method of Claim 4. A liquid crystal display device comprising the spacer for a liquid crystal display device according to claim 5.

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