JP2006301148A - Radiation-sensitive resin composition, protrusions and spacers formed therefrom, and liquid crystal display device comprising the same - Google Patents

Abstract

To provide a radiation-sensitive resin composition suitably used for simultaneously forming protrusions and spacers of a vertical alignment type liquid crystal display element.
[A] A copolymer of (a1) an ethylenically unsaturated carboxylic acid and / or an ethylenically unsaturated carboxylic acid anhydride and (a2) an ethylenically unsaturated compound other than (a1),
[B] A photosensitive composition containing a polymerizable compound having an ethylenically unsaturated bond and [C] a photopolymerization initiator, wherein the content of [C] photopolymerization initiator is [B] 100 parts by weight It is a radiation sensitive resin composition for forming simultaneously the protrusion and spacer of a vertical alignment type liquid crystal display element characterized by being 0.1 to 5 parts by weight.
[Selection figure] None

Description

  The present invention relates to a radiation-sensitive resin composition suitable for simultaneously forming protrusions and spacers of a vertical liquid crystal display element, protrusions and spacers formed therefrom, and a liquid crystal display element having the same.

Liquid crystal display panels are most widely used today among flat panel displays. Especially, TFT (thin film transistor) type liquid crystal display panels (TFT-LCD) are used in office automation equipment such as personal computers and word processors, liquid crystal televisions, etc. With the widespread use, the required performance for display quality has become increasingly severe.
The most widely used method among TFT-LCDs is a TN (Twisted Nematic) type LCD, and this method arranges polarizing films whose orientation directions differ by 90 degrees outside two transparent electrodes, An alignment film is arranged inside the two transparent electrodes, and a nematic liquid crystal is arranged between the two alignment films so that the alignment direction of the liquid crystal is twisted 90 degrees from one electrode side to the other electrode side. It is a thing. When non-polarized light is incident in this state, the linearly polarized light transmitted through one polarizing plate is transmitted through the liquid crystal while the polarization direction is shifted, so that it can be transmitted through the other polarizing plate, resulting in a bright state. Next, when a voltage is applied to both the electrodes to make the liquid crystal molecules stand upright, the linearly polarized light reaching the liquid crystal is transmitted as it is, so that it cannot be transmitted through the other polarizing plate and becomes dark. Thereafter, when the voltage is not applied again, the light state is restored.
Such a TN-type LCD has the same or better CRT as the contrast and color reproducibility in the front due to recent technological improvements. However, the TN type LCD has a big problem that the viewing angle is narrow.

In order to solve such problems, STN (Super Twisted Nematic) type LCDs and MVA (Multi-domain Vertically Aligned) type LCDs (vertical alignment type liquid crystal display panels) have been developed. Among these, the STN type LCD is a nematic type liquid crystal of a TN type LCD that is blended with a chiral agent that is a photoactive substance so that the alignment axis of liquid crystal molecules is twisted by 180 degrees or more between two electrodes. It is. The MVA type LCD uses a negative type liquid crystal having negative dielectric anisotropy and a vertical alignment film, and utilizes the birefringence mode instead of the optical rotation mode of the TN type LCD. The alignment direction of the liquid crystal at a position close to the alignment film is maintained almost vertical even in a non-exposed state, so that the contrast, viewing angle, etc. are excellent, and there is no need for rubbing treatment to align the liquid crystal. The process is also excellent (see Non-Patent Document 1 and Patent Document 1).
In the MVA type LCD, in order to allow the liquid crystal to take a plurality of orientation directions in one pixel region, the display-side electrode has a slit in one pixel region as a domain regulating means, In the same pixel region on the light incident side electrode, the position of the electrode is shifted from the position of the electrode to form a protrusion having a slope (for example, a triangular pyramid shape, a semi-convex lens shape, etc.).
Such protrusions are usually formed by photolithography, which has the advantage that microfabrication is possible and shape control is easy.

  On the other hand, it is necessary to install a predetermined spacer in the liquid crystal panel in order to keep the distance between the two substrates constant. Conventionally, spacer particles such as glass beads and plastic beads having a predetermined particle diameter have been used as such spacers. However, since these spacer particles are randomly distributed on the glass substrate, if the spacer is present in the effective pixel portion, the spacer is reflected or the incident light is scattered and the contrast of the liquid crystal panel is lowered. There was a problem. In order to solve these problems, a method has been adopted in which a spacer other than the effective pixel portion is formed by photolithography using a radiation sensitive resin composition.

The same process can be used for the protrusion formation and the spacer formation in that photolithography using a radiation sensitive resin is used, but the required performance differs as described below.
(1) The required film thickness differs between the protrusion and the spacer.
(2) The required shape is that the protrusion is a semi-convex lens shape, whereas the spacer is different from a columnar shape or a forward tapered shape.

In addition, since it is necessary to form an alignment film on the protrusions, sufficient wettability to the alignment film material is required so that no repelling occurs when the alignment film is formed in a later step.
On the other hand, the spacer is required to have a high compressive strength so as not to be deformed even by an external pressure applied to the liquid crystal panel.
Furthermore, both the protrusion and the spacer need to be resistant to heat applied in the subsequent panel assembly process.

  When the alignment film is formed on the protrusion, if the taper angle of the protrusion with respect to the substrate is too large, for example, if it is 30 degrees or more, the alignment film is printed on the upper portion of the protrusion, and a display defect occurs after the panel is formed. The possibility increases. Therefore, the taper angle of the protrusion with respect to the substrate is preferably 30 degrees or less.

  As described above, since the protrusion and the spacer are required to have different shapes and chemical properties, conventionally, it has been necessary to use different radiation-sensitive materials and form them in different steps. Patent Document 2 discloses that a negative photosensitive material can be used to form a protrusion and a spacer at the same time. However, in this publication, there is a feeling that should be used for such an application. No specific embodiment of the radiation composition is disclosed, and a radiation sensitive composition for forming the protrusion and the spacer at the same time is not yet known, and there is a strong demand for providing such a material. It has been.

Arihiro Takeda, Liquid Crystal, Japanese Liquid Crystal Society, April 25, 1999, Vol. 3, No. 2, 117 Japanese Patent Laid-Open No. 11-258605 JP 2001-83517 A

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 size is about the same as the substrate size. It is almost impossible to produce a mask, and it is difficult to cope with the batch exposure method.
Therefore, a step exposure method has been proposed as an exposure method that can be applied to a large substrate. However, in the step exposure method, since a single substrate is exposed several times, and each exposure requires time for alignment and step movement, reduction of throughput is regarded as a problem compared to the batch exposure method. .
In addition, in the batch exposure method, an exposure amount of about 3,000 J / m ² is possible, but in the case of the step exposure method, it is necessary to lower the exposure amount at each time, which is conventionally used for forming a spacer. In the radiation sensitive resin composition, it was difficult to achieve a sufficient spacer shape and film thickness with an exposure amount of 1,500 J / m ² or less.

Furthermore, recently, precipitation of insoluble components in the developer has become a problem. Conventional radiation-sensitive resin compositions used for spacer formation often use a photopolymerization initiator that is insoluble in an alkaline developer. However, in order to obtain the above-mentioned high throughput, the amount of photopolymerization initiator added is reduced. High sensitivity may be achieved by setting it higher. In such a case, after the unexposed portion after the spacer formation is dissolved and removed, the photopolymerization initiator may be precipitated in the developer after development, and the deposited photopolymerization initiator is reattached to the substrate to display the display element. Or a photopolymerization initiator may be deposited in a developing tank or a developing nozzle of a developing device to cause development failure. The problem of precipitation of the photopolymerization initiator has become more apparent with the recent increase in size of the substrate, that is, the increase in the area of the unexposed region.

  The present invention has been made in view of the above circumstances, and the object thereof is a radiation-sensitive resin composition suitably used for simultaneously forming the protrusions and spacers of a vertical alignment type liquid crystal display element, and formed therefrom. Protrusions and spacers, and a liquid crystal display device including them.

According to the present invention, the problem is firstly
[A] a copolymer of (a1) an ethylenically unsaturated carboxylic acid and / or an ethylenically unsaturated carboxylic acid anhydride and (a2) an ethylenically unsaturated compound other than (a1),
[B] A radiation-sensitive resin composition containing a polymerizable compound having an ethylenically unsaturated bond and [C] a photopolymerization initiator, wherein the content of [C] photopolymerization initiator is [B] 100. A radiation-sensitive resin composition (hereinafter referred to as “radiation-sensitive resin composition”) for simultaneously forming protrusions and spacers of a vertical alignment type liquid crystal display element, which is 0.1 to 5 parts by weight with respect to parts by weight This may be achieved by the object (b) ”.

  The present invention secondly comprises a forming method for simultaneously forming protrusions and spacers of a vertical alignment type liquid crystal display element characterized by including the following steps in the following order.

(1) The process of forming the coating film of said radiation sensitive composition on a board | substrate,
(2) A step of irradiating at least a part of the coating film under low oxygen conditions;
(3) Development step, and (4) Heating step.

  Thirdly, according to the present invention, there is provided a forming method (hereinafter referred to as “process”) for simultaneously forming protrusions and spacers of a vertical alignment type liquid crystal display device characterized in that the low oxygen condition is an inert gas atmosphere. a) ".

  Fourthly, the present invention provides a method for simultaneously forming protrusions and spacers of a vertical alignment type liquid crystal display element characterized in that the low oxygen condition is under reduced pressure (hereinafter referred to as “process (b)”). It may be said.)

  Fifthly, the present invention provides a forming method for simultaneously forming protrusions and spacers of a vertical alignment type liquid crystal display element, wherein the low oxygen condition is a condition in which the cover film is shielded from the ambient atmosphere. (Hereinafter also referred to as “process (c)”).

  Sixth, the present invention comprises a protrusion and a spacer formed by the above method.

Seventhly, the present invention comprises a liquid crystal display device comprising the above protrusion and spacer.
Hereinafter, the present invention will be described in detail.

Radiation sensitive resin composition (I)
-Copolymer [A]-
The component [A] in the radiation-sensitive resin composition (A) comprises (a1) an ethylenically unsaturated carboxylic acid and / or an ethylenically unsaturated carboxylic acid anhydride and (a2) an ethylenically unsaturated compound other than (a1) (Hereinafter also referred to as “copolymer [A]”).

Among the components constituting the copolymer [A], (a1) an ethylenically unsaturated carboxylic acid and / or an ethylenically unsaturated carboxylic acid anhydride (hereinafter referred to as “unsaturated carboxylic acid monomer”) (It may be referred to as “(a1)”), for example, monocarboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, 2-methacryloyloxyethyl succinic acid, 2-methacryloyloxyethyl hexahydrophthalic acid; Examples thereof include dicarboxylic acids such as acid, fumaric acid, citraconic acid, mesaconic acid, and itaconic acid; anhydrides of the dicarboxylic acid.
Among these unsaturated carboxylic acid monomers (a1), acrylic acid, methacrylic acid, maleic anhydride are available from the viewpoints of copolymerization reactivity, solubility of the resulting copolymer in an alkaline aqueous solution and easy availability. Etc. are preferred.
In the radiation sensitive resin composition (A), the unsaturated carboxylic acid monomer (a1) can be used alone or in admixture of two or more.

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

Examples of the ethylenically unsaturated compound other than (a2) include an epoxy group-containing ethylenically unsaturated compound.
Examples of the epoxy group-containing ethylenically unsaturated compound include:
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 ethylenically unsaturated compounds, 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, the (a2) epoxy group-containing ethylenically unsaturated compound can be used alone or in admixture of two or more.

Moreover, as (a2) other ethylenically unsaturated compounds, in addition to the epoxy group-containing ethylenically unsaturated compounds, 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 other ethylenically unsaturated compounds (a2) other than the epoxy group-containing ethylenically unsaturated compound, acrylic acid 2 is used from the viewpoint of copolymerization reactivity and solubility of the obtained [A] copolymer in an alkaline aqueous solution. -Methylcyclohexyl, tert-butyl methacrylate, tricyclomethacrylate [5.2.1.0 ^2,6 ] decan-8-yl, styrene, p-methoxystyrene, tetrahydrofuran-2-yl methacrylate, 1,3- Butadiene is preferred.
[A] In the copolymer, (a2) other ethylenically unsaturated compounds other than the epoxy group-containing ethylenically unsaturated compound can be used alone or in admixture of two or more.

    [A] In the copolymer, two or more types of (a2) may be used, and the total content of repeating units derived therefrom is 40 to 95% by weight, preferably 50 to 90% by weight, more preferably 60 ~ 85% by weight. In this case, if the total content of the repeating units derived from (a2) is less than 40% by weight, there is a tendency to cause swelling during development and increase in the viscosity of the solution. Tend to decrease. There is a tendency to cause swelling during development and increase in viscosity of the solution.

  The copolymer [A] is obtained by polymerizing, for example, (a1) an unsaturated carboxylic acid compound and (a2) an unsaturated compound other than (a1) in a suitable solvent in the presence of a radical polymerization initiator. Can be manufactured.

  Examples of the solvent used for the polymerization include alcohol, ether, glycol ether, ethylene glycol alkyl ether acetate, diethylene glycol, propylene glycol monoalkyl ether, propylene glycol alkyl ether acetate, propylene glycol alkyl ether propionate, and aromatic hydrocarbon. , Ketones, esters and the like.

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

Examples of esters include methyl acetate, ethyl acetate, propyl acetate, butyl acetate, ethyl 2-hydroxypropionate, methyl 2-hydroxy-2-methylpropionate, ethyl 2-hydroxy-2-methylpropionate, methyl hydroxyacetate, hydroxy Ethyl acetate, hydroxybutyl acetate, methyl lactate, ethyl lactate, propyl lactate, butyl lactate, methyl 3-hydroxypropionate, ethyl 3-hydroxypropionate, propyl 3-hydroxypropionate, butyl 3-hydroxypropionate, 2-hydroxy -3-methylbutanoate, methyl methoxyacetate, ethyl methoxyacetate, propyl methoxyacetate, butyl methoxyacetate, methyl ethoxyacetate, ethyl ethoxyacetate, propyl ethoxyacetate, butyl ethoxyacetate, propoxy Methyl acetate, ethyl propoxyacetate, propyl propoxyacetate, butyl propoxyacetate, methyl butoxyacetate, ethyl butoxyacetate, propyl butoxyacetate, butylbutoxyacetate, methyl 2-methoxypropionate, ethyl 2-methoxypropionate, 2-methoxypropionic acid Propyl, butyl 2-methoxypropionate, methyl 2-ethoxypropionate, ethyl 2-ethoxypropionate, propyl 2-ethoxypropionate, butyl 2-ethoxypropionate, methyl 2-butoxypropionate, ethyl 2-butoxypropionate Propyl 2-butoxypropionate, butyl 2-butoxypropionate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, propyl 3-methoxypropionate, 3-methoxypropyl Butyl pionate, methyl 3-ethoxypropionate, ethyl 3-ethoxypropionate, propyl 3-ethoxypropionate, butyl 3-ethoxypropionate, methyl 3-propoxypropionate, ethyl 3-propoxypropionate, 3-propoxypropionate Examples thereof include esters such as propyl acid, butyl 3-propoxypropionate, methyl 3-butoxypropionate, ethyl 3-butoxypropionate, propyl 3-butoxypropionate, and butyl 3-butoxypropionate.

Of these, ethylene glycol alkyl ether acetate, diethylene glycol, propylene glycol monoalkyl ether, and propylene glycol alkyl ether acetate are preferable, and diethylene glycol dimethyl ether, diethylene glycol ethyl methyl ether, propylene glycol methyl ether, and propylene glycol methyl ether acetate are particularly preferable. .
The said solvent can be used individually or in mixture of 2 or more types.

The radical polymerization initiator used for the polymerization is not particularly limited, and for example, 2,2′-azobisisobutyronitrile, 2,2′-azobis- (2,4-dimethylvalero). Nitrile), 2,2′-azobis- (4-methoxy-2,4-dimethylvaleronitrile), 4,4′-azobis (4-cyanovaleric acid), dimethyl 2,2′-azobis (2-methylpro) Azo compounds such as pionate), 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile); benzoyl peroxide, lauroyl peroxide, t-butylperoxypivalate, 1,1-bis (t-butyl) Peroxy) organic peroxides such as cyclohexane; hydrogen peroxide and the like. Moreover, when using a peroxide as a radical polymerization initiator, it is good also as a redox type initiator combining it and a reducing agent.
These radical polymerization initiators can be used alone or in admixture of two or more.
The copolymer [A] thus obtained may be used for the preparation of the radiation-sensitive resin composition in the form of a solution, or may be separated from the solution and used for the preparation of the radiation-sensitive resin composition. .

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

-Polymerizable compound [B]-
The component [B] in the radiation-sensitive resin composition (A) is a polymerizable compound having an ethylenically unsaturated bond (hereinafter sometimes referred to as “polymerizable compound [B]”).
Although it does not specifically limit as polymeric compound [B], Monofunctional, bifunctional, or trifunctional or more (meth) acrylic acid ester has favorable polymerizability, and obtained protrusion and spacer This is preferable from the viewpoint of improving the strength.

  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. can be mentioned, and commercially available products include, for example, Aronix M -101, M-111, M-114 (manufactured by Toa Gosei Co., Ltd.); KAYARAD TC-110S, TC-120S (manufactured by Nippon Kayaku Co., Ltd.) ; Viscoat 158, mention may be made of the 2311 (manufactured by Osaka Organic Chemical Industry Ltd.) and the like.

  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, etc. As commercial products, for example, Aronix M-210, M-240, M-6200 (manufactured by Toa Gosei Co., Ltd.) , KAYARAD HDDA, the HX-220, (manufactured by Nippon Kayaku Co.) Same R-604, Viscoat 260, the 312, the 335HP (manufactured by Osaka Organic Chemical Industry 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, etc. Can do.
In particular, a (meth) acrylate having 9 or more functional groups has an alkylene straight chain and an alicyclic structure, a compound containing two or more isocyanate groups, and a trifunctional, tetrafunctional and 5 functional group containing one or more hydroxyl groups in the molecule. The urethane acrylate compound obtained by making a functional (meth) acrylate compound react is mentioned.
As said commercial item, for example, Aronix M-309, M-400, M-405, M-450, M-7100, M-8030, M-8060, M-8060, TO-1450 (Toa Gosei ( KAYARAD TMPTA, DPHA, DPCA-20, DPCA-30, DPCA-60, DPCA-60, DPCA-120 (manufactured by Nippon Kayaku Co., Ltd.), Biscote 295, 300, 360, GPT, 3PA, 400 (produced by Osaka Organic Chemical Industry Co., Ltd.) and the like. Examples of commercially available products of polyfunctional urethane acrylates having 9 or more functional groups include New Frontier R-1150 (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), KAYARAD DPHA-40H (manufactured by Nippon Kayaku Co., Ltd.) Is mentioned.

Among these monofunctional, bifunctional, or trifunctional or higher (meth) acrylic acid esters, trifunctional or higher functional (meth) acrylic acid esters are more preferable, and in particular, trimethylolpropane triacrylate, pentaerythritol triacrylate, Pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate are preferred.
The monofunctional, bifunctional, or trifunctional or higher (meth) acrylic acid esters can be used alone or in combination of two or more.

  In the radiation sensitive resin composition (A), the amount of the polymerizable compound [B] used is preferably 50 to 140 parts by weight, more preferably 60 to 120 parts by weight, relative to 100 parts by weight of the copolymer [A]. Part. In this case, if the amount of the polymerizable compound [B] used is less than 50 parts by weight, there is a risk of developing residue during development, whereas if it exceeds 140 parts by weight, the hardness of the resulting protrusions and spacers tends to decrease. is there.

-Photopolymerization initiator [C]-
The photopolymerization initiator as used in the present invention means a component that generates an active species capable of initiating polymerization of the polymerizable compound [B] by exposure with visible light, ultraviolet light, far ultraviolet light, charged particle beam, X-ray or the like. To do. The component [C] in the photosensitive resin composition (A) is preferably not micro-associated so as to give a high quantum yield in the coating film of the composition, and it is preferable that the loss of light energy due to the self-quenching effect is small. Therefore, it is preferable that the component [C] in the photosensitive resin composition (a) is uniformly dispersed. In order to disperse uniformly in the photosensitive resin composition (a) composed of an organic substance, It preferably has a solubility parameter substantially equivalent to that of the composition, and it is preferable that [C] alone has a hydrophobicity that does not dissolve in an alkaline developer.
The usage-amount of the photoinitiator [C] in a radiation sensitive resin composition (I) is 0.1-5 weight part with respect to polymeric compound [B], Preferably it is 0.2-3 weight part. More preferably, it is 0.2 to 1.5 parts by weight. If the amount exceeds 5 parts by weight, the radical active species generated from [C] may be deactivated by the excessively generated radical active species, which may hinder the smooth progress of photopolymerization of the polymerizable compound [B]. In addition, [C] tends to be micro-aggregated, and the energy of light cannot be effectively used due to self-quenching, or [C] in the developer tends to precipitate. On the other hand, if it is less than 0.1 part by weight, the heat resistance, surface hardness and chemical resistance tend to be lowered.
A photoinitiator [C] can be used individually or in mixture of 2 or more types.
In the radiation sensitive resin composition (a), it is possible to effectively use radical species generated from the photopolymerization initiator [C] by combining with the above processes (a), (b) and (c). Thus, it becomes possible to obtain protrusions and spacers having sufficient sensitivity and adhesion even with an exposure amount of 1500 J / m ² or less.

Specific examples of the compound [C] include, for example, biimidazole compounds, benzoin compounds, acetophenone compounds, benzophenone compounds, α-diketone compounds, polynuclear quinone compounds, xanthone compounds, phosphine compounds, triazines. And the like, and oxime compounds.
Examples of oxime compounds 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- Onoxime-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. .-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 1,2-octadion-1- [4- (phenylthio) phenyl] -2- (O-benzoyloxime), 1,2-butanedione-1- [4- (phenylthio) phenyl] -2- (O-benzoyl) Oxime), 1,2-butanedione-1- [4- (phenylthio) phenyl] -2- (O-acetyloxime), 1,2-octadion-1- [4- (methylthio) phenyl] -2- (O -Benzoy Oxime), 1,2-octadion-1- [4- (phenylthio) phenyl] -2- (O- (4-methylbenzoyloxime)) and the like. Of these, 1,2-octadion-1- [4- (phenylthio) phenyl] -2- (O-benzoyloxime) is particularly preferable.
Etc. Of these, 1- [9-ethyl-6- (2-methylbenzoyl) -9.H.-carbazol-3-yl] -ethane-1-one oxime-O-acetate is particularly preferable.

Examples of the acetophenone compounds include α-hydroxy ketone compounds, α-amino ketone compounds, and other compounds.
Specific examples of the α-hydroxyketone compound include 1-phenyl-2-hydroxy-2-methylpropan-1-one, 1- (4-i-propylphenyl) -2-hydroxy-2-methylpropane- 1-one, 4- (2-hydroxyethoxy) phenyl- (2-hydroxy-2-propyl) ketone, 1-hydroxycyclohexyl phenyl ketone and the like can be mentioned, and specific examples of the α-aminoketone compound include: Examples include 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1, and the like. Specific examples of compounds other than these include 2,2-dimethoxyacetophenone, 2,2-diethoxyacetophenone, 2, - it can be given dimethoxy-2-phenyl acetophenone and the like.
As a specific example of the biimidazole compound,
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) -4,4 ′, 5,5′-tetraphenyl-1,2′-biimidazole,
2,2′-bis (2,4-dibromophenyl) -4,4 ′, 5,5′-tetraphenyl-1,2′-biimidazole,
Examples include 2,2′-bis (2,4,6-tribromophenyl) -4,4 ′, 5,5′-tetraphenyl-1,2′-biimidazole.

Among the 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, is particularly preferable. 2'-biimidazole.
In order to sensitize the biimidazole compound, an aliphatic or aromatic compound having a dialkylamino group (hereinafter sometimes referred to as “sensitizer [D]”) can be used.
Specific examples of the sensitizer [D] include, for example, N-methyldiethanolamine, 4,4′-bis (dimethylamino) benzophenone, 4,4′-bis (diethylamino) benzophenone, ethyl p-dimethylaminobenzoate. , P-dimethylaminobenzoic acid i-amyl and the like. Of these sensitizers, 4,4′-bis (diethylamino) benzophenone is preferred.

Two or more of these sensitizers [D] may be used at the same time.
The amount of the sensitizer [D] used is preferably 0.1 to 50 parts by weight, more preferably 1 to 20 parts by weight with respect to 100 parts by weight of [A].
If the amount of the compound [D] is less than 0.1 parts by weight, the resulting protrusions and spacers tend to be slipped or have poor pattern shape. Tend to occur.

  When a biimidazole compound is used, a thiol compound (hereinafter sometimes referred to as “thiol compound [D-2]”) may be used as the hydrogen donor compound. The biimidazole compound is sensitized by a benzophenone compound having a dialkylamino group, and the biimidazole compound is cleaved to generate an imidazole radical. In this case, a high radical polymerization initiating ability is not expressed, and an unfavorable shape such as a reverse tapered shape is often obtained. This problem is alleviated by adding the thiol compound [D-2] to a system in which a biimidazole compound and a benzophenone compound having a dialkylamino group coexist. A hydrogen radical is donated from the thiol compound to the imidazole radical, thereby generating a compound having a neutral imidazole and a sulfur radical having a high polymerization initiating ability. Thereby, it becomes a more preferable forward taper shape from a reverse taper shape.

The use ratio of the thiol compound [D-2] is preferably 0.1 to 50 parts by weight, more preferably 1 to 20 parts by weight with respect to 100 parts by weight of the compound [C]. . If the amount of the thiol-based compound [D-2] is less than 0.1 parts by weight, the resulting protrusions and spacers tend to be slipped or have poor pattern shapes. A pattern shape defect tends to occur.

Specific examples thereof include aromatic thiols such as 2-mercaptobenzothiazole, 2-mercaptobenzoxazole, 2-mercaptobenzimidazole, 2-mercapto-5-methoxybenzothiazole, 2-mercapto-5-methoxybenzimidazole, 3 -Aliphatic monothiols such as mercaptopropionic acid, methyl 3-mercaptopropionate, ethyl 3-mercaptopropionate and octyl 3-mercaptopropionate. Examples of the bifunctional or higher aliphatic thiol include 3,6-dioxa-1,8-octanedithiol, pentaerythritol tetra (mercaptoacetate), pentaerythritol tetra (3-mercaptopropionate), and the like.

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

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

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

These surfactants can be used alone or in admixture of two or more.
The blending 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 copolymer [A]. In this case, when the compounding amount of the surfactant exceeds 5 parts by weight, there is a tendency that film roughening is likely to occur during coating.

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

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

  In order to improve heat resistance, an N- (alkoxymethyl) glycoluril compound, an N- (alkoxymethyl) melamine compound, and a compound having a bifunctional or higher functional epoxy group in one molecule can be added. Specific examples of the N- (alkoxymethyl) glycoluril compound include N, N, N, N-tetra (methoxymethyl) glycoluril, N, N, N, N-tetra (ethoxymethyl) glycoluril, N, N, N, N-tetra (n-propoxymethyl) glycoluril, N, N, N, N-tetra (i-propoxymethyl) glycoluril, N, N, N, N-tetra (n-butoxymethyl) glycol Examples include uril, N, N, N, N-tetra (t-butoxymethyl) glycoluril and the like. Of these, N, N, N, N-tetra (methoxymethyl) glycoluril is particularly preferable. Specific examples of the N- (alkoxymethyl) melamine compound include N, N, N, N, N, N-hexa (methoxymethyl) melamine, N, N, N, N, N, N-hexa (ethoxymethyl). ) Melamine, N, N, N, N, N, N-hexa (n-propoxymethyl) melamine, N, N, N, N, N, N-hexa (i-propoxymethyl) melamine, N, N, N , N, N, N-hexa (n-butoxymethyl) melamine, N, N, N, N, N, N-hexa (t-butoxymethyl) melamine and the like. Among these, N, N, N, N, N, N-hexa (methoxymethyl) melamine is particularly preferable. Examples of these commercially available products include Nicalac N-2702, MW-30M (manufactured by Sanwa Chemical Co., Ltd.) and the like.

Examples of the compound having a bifunctional or higher functional epoxy group in one molecule include ethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, and polypropylene glycol diglycidyl. Examples include ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerin diglycidyl ether, trimethylolpropane triglycidyl ether, hydrogenated bisphenol A diglycidyl ether, and bisphenol A diglycidyl ether. Specific examples of these commercially available products include Epolite 40E, Epolite 100E, Epolite 200E, Epolite 70P, Epolite 200P, Epolite 400P, Epolite 40E, Epolite 1500NP, Epolite 1600, Epolite 80MF, Epolite 100MF, Epolite 4000, Epolite 3,002 ( As mentioned above, Kyoeisha Chemical Co., Ltd.) can be mentioned. These can be used alone or in combination of two or more.

The composition solution radiation-sensitive resin composition (a) is usually prepared by using components such as a copolymer [A], a polymerizable compound [B], a photopolymerization initiator [C] and the like in an appropriate solvent. Dissolved and prepared as a composition solution.
As the solvent used for the preparation of the composition solution, those that uniformly dissolve each component constituting the radiation-sensitive resin composition (i) and that do not react with each component are used. The thing similar to the solvent illustrated about the superposition | polymerization which manufactures copolymer [A] can be mentioned.
Of these solvents, alcohols, glycol ethers, ethylene glycol alkyl ether acetates, esters, and diethylene glycol are preferably used from the viewpoints of solubility of each component, reactivity with each component, and ease of film formation. Among these, for example, benzyl alcohol, 2-phenylethyl alcohol, 3-phenyl-1-propanol, ethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol diethyl ether, diethylene glycol ethyl methyl ether, diethylene glycol dimethyl ether, propylene glycol monomethyl ether Propylene glycol monomethyl ether acetate, methyl methoxypropionate, and ethyl ethoxypropionate can be particularly preferably used.

  Furthermore, in order to improve the in-plane uniformity of the film thickness together with the solvent, a high boiling point solvent can be used in combination. Examples of the high boiling point solvent that can be used in combination include N-methylformamide, N, N-dimethylformamide, N-methylformanilide, N-methylacetamide, N, N-dimethylacetamide, N-methylpyrrolidone, dimethylsulfoxide, and benzylethyl ether. , Dihexyl ether, acetonyl acetone, isophorone, caproic acid, caprylic acid, 1-octanol, 1-nonanol, benzyl acetate, ethyl benzoate, diethyl oxalate, diethyl maleate, γ-butyrolactone, ethylene carbonate, propylene carbonate, phenyl Examples include cellosolve acetate. Of these, N-methylpyrrolidone, γ-butyrolactone, and N, N-dimethylacetamide are preferable.

When a high boiling point solvent is used in combination as the solvent of the radiation sensitive resin composition of the present invention, the amount used is preferably 50% by weight or less, more preferably 40% by weight or less, still more preferably 30%, based on the total amount of the solvent. It can be made into weight% or less. If the amount of the high-boiling solvent used exceeds this amount, the coating film thickness uniformity, sensitivity, and residual film rate may decrease.
When preparing the radiation-sensitive resin composition of the present invention in a solution state, components other than the solvent in the solution, that is, the copolymer [A], [B] component and [C] component and optionally added The proportion of the total amount of the other components can be arbitrarily set according to the purpose of use, the value of the desired film thickness, etc., for example, 5 to 50% by weight, preferably 10 to 40% by weight, and more preferably 15%. -35% by weight.
The composition solution thus prepared can be used after being filtered using a Millipore filter having a pore size of about 0.5 μm.

  The radiation sensitive resin composition (A) can be used particularly suitably for the formation of protrusions and spacers of a vertical alignment type liquid crystal display element.

The method of forming the protrusions and spacers Next, a method of forming protrusions and spacers of the present invention will be described with reference to radiation-sensitive resin composition of the present invention.
The method for forming protrusions and spacers of the present invention is characterized by including the following steps in the order described below.
(1) The process of forming the coating film of the radiation sensitive composition of this invention 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.

Hereinafter, each of these steps will be described sequentially.
(1) Step of forming a coating film of the radiation-sensitive composition of the present invention on a substrate When forming the protrusions and spacers of a vertical alignment type liquid crystal display device using the photosensitive resin composition (a), the composition A method of forming a coating film by applying a product solution to the surface of a substrate or film and then pre-baking to remove the solvent, or a coating film once formed on the substrate or film to another substrate or film A method of transferring onto a film is used.
The coating method of the composition solution is not particularly limited, and 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, an ink jet coating method or the like can be used. In particular, a spin coating method and a slit die coating method are 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.

(2) Step of irradiating at least part of the coating film Next, radiation is exposed to at least part of the formed coating film. In this case, when exposing a part of the film, the exposure is performed through a photomask having a predetermined pattern.
Here, it is preferable that the region to be the protrusion and the region to be the spacer are exposed with substantially the same exposure amount in consideration of productivity. In this case, under a constant exposure gap, the exposure illuminance decreases as the mask opening width decreases, so the degree of cross-linking decreases, and as a result, the flow tends to flow during post-baking, resulting in a difference in height. It becomes.
Further, when the control of the spacer and the protrusion shape is strictly required, the exposure may be performed with a different substantial exposure amount as necessary. At this time, the effective exposure amount of the region to be the projection is made smaller than the effective exposure amount of the spacer portion. By exposing each region with such an effective exposure amount, the film thickness of the spacer portion can be easily made larger than the film thickness of the protrusion. Although an appropriate method can be adopted as a method of exposing with different effective exposure amounts, for example, the following methods can be used.
(1) A method of exposing through a pattern mask having a portion having a large radiation transmittance and a portion having a small radiation transmittance.
(2) A method of performing multiple exposures using two types of pattern masks having different patterns.
(3) A method of performing both exposure from the upper surface of the coating film and exposure from the back surface of the substrate.
As the radiation to be used, visible light, ultraviolet light, far ultraviolet light, electron beam, X-ray and the like can be used. However, radiation containing a wavelength in the range of 190 to 450 nm is preferable, and radiation containing 365 nm in particular (ultraviolet light) is particularly preferable. .
The exposure step is preferably performed under low oxygen conditions, for example, a process (a) for exposure and pattern formation under an inert gas atmosphere, a process (b) for exposure and pattern formation under vacuum, or a cover film A process (c) is preferably applied in which exposure is performed and a pattern is formed in a state of being shielded from the external atmosphere.
As the cover film layer that shields from the external atmosphere, a film layer that efficiently transmits the exposure and does not lose light energy is preferable. An organic film, an inorganic film, etc. are used. The cover film layer is removed after exposure and before development, or dissolved and removed in a developer during development. When dissolved and removed during development, the organic composition must be water-soluble or alkali-soluble.

(3) Development Step Next, 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.

(4) Heating step Next, the obtained pattern is subjected to a predetermined temperature, for example, 150 to 250 ° C., for a predetermined time, for example, 5 to 30 minutes on the hot plate, in an oven by a heating device such as a hot plate or an oven. Predetermined protrusions and spacers can be obtained by heating (post-baking) for 30 to 180 minutes.

Here, specific examples of the composition of the preferred radiation-sensitive resin composition (a) are as follows (i) to (vii).
(I) The component constituting the copolymer [A] is an epoxy resin in which the unsaturated carboxylic acid monomer (a1) is a single group of acrylic acid, methacrylic acid and maleic anhydride or a mixture of two or more types. The group-containing ethylenically unsaturated monomer (a2) is glycidyl methacrylate, 6,7-epoxyheptyl methacrylate, o-vinylbenzyl glycidyl ether, m-vinylbenzyl glycidyl ether, p-vinylbenzyl glycidyl ether, acrylic acid 2 -Methyl cyclohexyl, tert-butyl methacrylate, tricyclo [5.2.1.0 ^2,6 ] decan-8-yl methacrylate, styrene, p-methoxystyrene, tetrahydrofurfuryl methacrylate, and 1,3-butadiene. A composition comprising a group alone or a mixture of two or more.
(Ii) In the copolymer [A], the content of the repeating unit derived from the unsaturated carboxylic acid monomer (a1) is 5 to 50% by weight, more preferably 10 to 40% by weight, The composition according to (i), wherein the content of the repeating unit derived from is from 10 to 70% by weight, more preferably from 20 to 60% by weight.
(Iii) (i) or (i) wherein the polymerizable compound [B] is a monofunctional, bifunctional or trifunctional or higher (meth) acrylic acid ester, particularly preferably a trifunctional or higher functional (meth) acrylic acid ester. The composition of ii).

(Vi) The amount of the polymerizable compound [B] used is 50 to 140 parts by weight, more preferably 60 to 120 parts by weight with respect to 100 parts by weight of the copolymer [A], and the photopolymerization initiator [C ] In any one of (i) to (vi) above, preferably 0.5 to 5 parts by weight, more preferably 0.5 to 3 parts by weight, based on 100 parts by weight of the polymerizable compound [B]. Composition.

By using the photosensitive resin composition (a) of the present invention and applying the pattern formation process (a) (b) or (c) suitable for the photosensitive resin composition, the mask pattern can be designed with high sensitivity. The size can be faithfully reproduced, and the adhesion to the substrate is excellent, making it possible to obtain sufficient protrusions and spacers with an exposure amount of 1500 J / m ² or less, solving the problem of precipitation of the photopolymerization initiator in the developer. In addition, protrusions and spacers for a vertical alignment type liquid crystal display element excellent in strength, heat resistance, and the like can be formed.
Further, the vertical alignment type liquid crystal display element of the present invention is provided with protrusions and spacers having excellent performance such as pattern shape, spacer strength, rubbing resistance, adhesion to a transparent substrate, heat resistance, etc. High reliability can be expressed.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. However, the present invention is not limited to these examples.
Synthesis example 1
A flask equipped with a condenser and a stirrer was charged with 5 parts of 2,2′-azobis (isobutyronitrile) and 250 parts of diethylene glycol methyl ethyl ether, followed by 35 parts of 2-methacryloyloxyethyl succinic acid, n methacrylate. -After charging 25 parts of butyl methacrylate and 35 parts of benzyl methacrylate and replacing with nitrogen, 5 parts by weight of 1,3-butadiene was further added, and the temperature of the solution was raised to 90 ° C while gently stirring. By keeping the polymerization for a time, an [A] copolymer solution having a solid content concentration of 28.0% was obtained. This is referred to as [A-1] polymer.
With respect to the obtained [A-1] polymer, Mw was measured by using GPC (Gel Permeation Chromatography) HLC-8020 (trade name, manufactured by Tosoh Corporation) and found to be 12,000.

Synthesis example 2
A flask equipped with a condenser and a stirrer was charged with 5 parts by weight of 2,2′-azobis (2,4-dimethylvaleronitrile) and 200 parts by weight of diethylene glycol methyl ethyl ether, followed by 18 parts by weight of methacrylic acid and methacrylic acid. After charging 40 parts by weight of glycidyl, 5 parts by weight of styrene, and 32 parts by weight of tricyclo [5.2.1.0 ^2,6 ] decan-8-yl methacrylate, and substituting with nitrogen, 5 weights of 1,3-butadiene is further added. The temperature of the solution was raised to 70 ° C. while gently stirring, and the temperature was maintained for 5 hours for polymerization to obtain a solution of copolymer [A-2].
The solid content concentration of this solution was 33.0% by weight, and Mw of the copolymer [A-2] was 11,000.

Examples 1-4
Preparation of Composition Solution 100 parts by weight (solid content) of the copolymer [A-1] obtained in Synthesis Example 1 as a copolymer [A], and KAYARAD DPHA (Nippon Kayaku) as a polymerizable compound [B] Co., Ltd.) 80 parts by weight, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one (trade name “Irgacure 369”, Ciba Specialty as photopolymerization initiator [C] -1 part by weight of Chemicals) was dissolved in propylene glycol monomethyl ether acetate so that the solid content concentration was 30% by weight, and then filtered through a Millipore filter having a pore size of 0.2 µm to obtain a composition solution (S-1 ) Was prepared.

Formation of Protrusions and Spacers Protrusions and spacers were formed by the following processes (I-1) to (I-4) or (i-1). The applied process is shown in Table 2.
(I-1) Formation of protrusions and spacers 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. Formed.
Next, in the process (a) in which the inside of the exposure machine chamber is replaced with a nitrogen gas atmosphere with an exposure gap of 150 μm through a photomask having a 5 μm and 15 μm round residual pattern, the intensity at 365 nm is 250 W / mm. m ² UV light was exposed for 4 seconds. Then, after developing with a 0.05% by weight aqueous solution of potassium hydroxide at 25 ° C. for a predetermined time, washing with pure water for 1 minute, and further heating in an oven at 220 ° C. for 60 minutes, the protrusions and spacers are removed once. Formed simultaneously by exposure. Protrusions were formed through a 5 μm remaining pattern photomask, and spacers were formed through a 15 μm round remaining pattern photomask.
(I-2) Formation of protrusions and spacers A coating film having a thickness of 4.0 μm was formed in the same manner as in (I-1). A mask and an exposure gap were set in the same manner as in (I-1), and exposure was performed in the same manner as in (I-1) in process (b) in which the inside of the exposure machine chamber was under reduced pressure (20 mmHg). Next, as in (I-1), development, rinsing and heating were performed to form a spacer.
(I-3) Formation of protrusions and spacers After forming a coating film having a film thickness of 4.0 μm as in (I-1), NFC-620 (trade name: JSR Corporation) is applied under predetermined conditions to cover A film is formed. A mask and an exposure gap were set in the same manner as in (I-1), and exposure was performed in the same manner as in (I-1) in the process (c) for blocking from the ambient atmosphere. Next, development was carried out in the same manner as in (I-1) to wash away NFC-620, and at the same time a pattern was formed, followed by rinsing and heating to form a spacer.
(I-4) Formation of protrusions and spacers After forming a coating film having a thickness of 4.0 μm on a PET film having a thickness of 50 μm in the same manner as (I-1), ARTON having a thickness of 100 μm (trade name: JSR stock) Company) Paste on film. A mask and an exposure gap were set in the same manner as in (I-1), and exposure was performed in the same manner as in (I-1) in the process (c) in which exposure was performed through a PET film. Next, after peeling off the PET film, development, rinsing and heating were performed in the same manner as in (I-1) to form a spacer.
(I-1) Formation of protrusions and spacers (comparative example)
Similarly to (I-1), the above composition solution was applied on a non-alkali glass substrate using a spinner and then pre-baked on a hot plate at 80 ° C. for 3 minutes to form a coating film having a thickness of 4.0 μm. did.
Next, the obtained coating film was exposed to UV light having an intensity of 250 W / m ² at 365 nm in an air atmosphere with an exposure gap of 150 μm through a photomask having a left pattern of 5 μm and 15 μm circles for 4 seconds. Then, after developing with a 0.05% by weight aqueous solution of potassium hydroxide at 25 ° C. for a predetermined time, washing with pure water for 1 minute, and further heating in an oven at 220 ° C. for 60 minutes, the protrusions and spacers are removed once. Formed simultaneously by exposure. Protrusions were formed through a photomask having a remaining pattern of 5 μm, and spacers were formed through a photomask having a remaining pattern of 15 μm.

(II) Sensitivity evaluation In the spacer pattern obtained by any of the processes (I-1) to (I-4) or (i-1), the sensitivity is such that the remaining film ratio after development is 90% or more. If it is 1500 J / m ² or less, it can be said that the sensitivity is good.

(III) Evaluation of pattern cross-sectional shape The cross-sectional shape of the pattern obtained by any one of the processes (I-1) to (I-4) or (i-1) was observed with a scanning electron microscope. The cross-sectional shapes of the obtained protrusions and spacers were evaluated according to which of A to E shown in FIG. In the case of protrusions, the cross-sectional shape is good when it is a semi-convex lens shape as shown in FIG. 1D, and when it is a regular triangle shape as shown in FIG. is not.
On the other hand, when the spacer is formed in a columnar shape as shown in FIG. 1A or a forward taper shape as shown in FIG. On the other hand, as shown in FIG. 1C, a pattern is also formed during the subsequent rubbing process even in the case of an inversely tapered shape (a cross-sectional shape and an inverted triangle shape in which the side of the film surface is longer than the side on the substrate side). Since the risk of peeling off becomes very large, it can be said that the cross-sectional shape is poor.

(IV) Evaluation of Spacer Strength The compression strength of the spacer obtained by any one of the above processes (I-1) to (I-4) or (i-1) was measured using a micro compression tester (DUH-201, ) Manufactured by Shimadzu Corporation). The amount of deformation when a load of 10 mN was applied was measured with a flat indenter with a diameter of 50 μm (measurement temperature: 23 ° C.). When this value is 0.5 or less, the compressive strength is good. The results are shown in Table 2.

(V) Evaluation of rubbing resistance AL3046 (manufactured by JSR Corporation) is used as a liquid crystal aligning agent on the substrate obtained by any one of the processes (I-1) to (I-4) or (i-1). It applied with the printing machine for liquid crystal aligning film application | coating, and it dried at 180 degreeC for 1 hour, and formed the coating film of the orientation agent with a dry film thickness of 0.05 micrometer.
The coating film was rubbed with a rubbing machine having a roll around which a nylon cloth was wound at a roll rotation speed of 500 rpm and a stage moving speed of 1 cm / sec. Table 2 shows the presence or absence of scraping or peeling of the spacer pattern.

(VI) Evaluation of adhesion The evaluation was performed in the same manner as in any of the above (I-1) to (I-4) or (i-1) except that no pattern mask was used. A cured film was formed and an adhesion test was conducted. The test method followed the cross-cut tape method of 8.5.2 in the adhesion test of JIS K-5400 (1900) 8.5. Table 2 shows the number of the remaining grids.

(VII) Precipitates in Developer Using 5 4-inch glass substrates and carrying out in the same manner as in any of the above processes (I-1) to (I-4) or (i-1), 50 cc Development is performed by immersing in the above developer. The developer was stored at room temperature in a dark place for 3 days, and the deposit was verified visually and under a microscope.

Examples 5-12, Comparative Examples 1-3
In Example 1, a composition solution was prepared and a spacer was formed in the same manner as in Example 1 except that the types and amounts shown in Table 1 were used as the components [A] to [D]. And evaluated. The addition amount of [B]-[D] is a weight ratio with respect to 100 weight part of polymeric compound [A].
In Table 1, the abbreviations of the components indicate the following compounds.
(B-1): KAYARAD DPHA (manufactured by Nippon Kayaku Co., Ltd.)
(B-2): KAYARAD DPHA-40H (manufactured by Nippon Kayaku Co., Ltd.)
(C-1): 1- [9-Ethyl-6- (2-methylbenzoyl) -9.H.-carbazol-3-yl] -ethane-1-one oxime-O-acetate (Ciba Specialty Chemicals) CGI-242)
(C-2): 1,2-octadion-1- [4- (phenylthio) phenyl] -2- (O-benzoyloxime) (CGI-124, manufactured by Ciba Specialty Chemicals)
(C-3): 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one (Irgacure 907 manufactured by Ciba Specialty Chemicals)
(C-4): 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1
(Irgacure 369 manufactured by Ciba Specialty Chemicals)
(C-5): 2,2′-bis (2,4-dichlorophenyl) -4,4 ′, 5,5′-tetraphenyl-1,2′-biimidazole (C-6) 2,2′- Bis (2-chlorophenyl) -4,4 ′, 5,5′-tetraphenyl-1,2′-biimidazole (D-1): 4,4′-bis (diethylamino) benzophenone (D-2): 2 -Mercaptobenzothiazole In Table 1,-mark shows that this component is not added.

It is a schematic diagram which illustrates the cross-sectional shape of protrusion and a spacer.

Claims (7)

[A] a copolymer of (a1) an ethylenically unsaturated carboxylic acid and / or an ethylenically unsaturated carboxylic acid anhydride and (a2) an ethylenically unsaturated compound other than (a1),
[B] A photosensitive composition containing a polymerizable compound having an ethylenically unsaturated bond and [C] a photopolymerization initiator, wherein the content of [C] photopolymerization initiator is [B] 100 parts by weight A radiation-sensitive resin composition for simultaneously forming protrusions and spacers of a vertical alignment type liquid crystal display element, which is 0.1 to 5 parts by weight based on the weight. A forming method for simultaneously forming protrusions and spacers of a vertical alignment type liquid crystal display element, comprising the following steps in the following order.
(1) The process of forming the coating film of the radiation sensitive composition of Claim 1 on a board | substrate,
(2) A step of irradiating at least a part of the coating film under low oxygen conditions;
(3) Development step, and (4) Heating step. 3. The method for simultaneously forming protrusions and spacers of a vertical alignment type liquid crystal display device according to claim 2, wherein the low oxygen condition is an inert gas atmosphere. 3. The method for simultaneously forming protrusions and spacers of a vertical alignment type liquid crystal display device according to claim 2, wherein the low oxygen condition is under reduced pressure. 3. The method for simultaneously forming protrusions and spacers of a vertical alignment type liquid crystal display element according to claim 2, wherein the low oxygen condition is a condition in which the cover film is shielded from the ambient atmosphere. A protrusion and a spacer formed by the method according to claim 3. A liquid crystal display device comprising the protrusion according to claim 6 and a spacer.

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