JP6660678B2 - Photoresist pattern forming method - Google Patents

Description

  The present invention relates to a method for forming a photoresist pattern, and more particularly, to a method for forming a photoresist pattern that does not require a thermosetting step after development.

  Photolithography is the most widely used method for forming various fine patterns, such as semiconductors, thin film transistors, and touch electrodes. After depositing a material for forming a pattern on a substrate, the photoresist corresponds to the pattern. This is a method in which a fine pattern is obtained by forming a resist pattern and then etching except for the portion where the resist pattern is formed.

  A general method of forming a photoresist pattern using a photoresist is a film forming process of applying a photosensitive resin composition for a photoresist on a deposited film of a material to be formed with a pattern, and a pattern to be formed. An exposure step of selectively irradiating the photoresist photosensitive resin film with light using a mask manufactured corresponding to the above, and removing the exposed areas and the unexposed areas separately ( (A part removed by the positive method and a part removed by the negative method are different from each other).

  In addition, by performing a pre-bake step before the exposure step, the formed resin film is prevented from moving, and a post-bake (post-bake) step is performed after the development step. Improves the durability of the resist pattern, such as chemical resistance and heat resistance.

  However, in recent years, due to the diversification of the use area of the photoresist, a polymer substrate which is vulnerable to heat, such as a flexible display device, may be used, so that the heat treatment conditions in the post-bake process have to be performed more gently. There is no situation.

  However, in such a case, there is a problem that the durability of the photoresist pattern is reduced and the reliability of the resist pattern in the photolithography process is reduced.

Korean Patent Publication No. 2003-0082875

  An object of the present invention is to provide a method for forming a photoresist pattern that does not require a post-baking step.

  It is another object of the present invention to provide a method capable of forming a photoresist pattern having excellent reliability such as heat resistance and chemical resistance without performing a post-baking step.

  1. A photoresist pattern forming method comprising a film forming step, an exposing step, and a developing step, wherein an additional exposing step is further performed after the developing step.

  2. Item 1. The method of forming a photoresist pattern according to Item 1, wherein the additional exposing step is performed at 4 to 20 times the energy of the exposing step before the developing step.

  3. Item 1. The method of forming a photoresist pattern according to Item 1, wherein the additional exposure step is an overall exposure performed without a mask.

  4. In the above item 1, the photoresist pattern forming method, wherein the substrate on which the photoresist pattern is formed is a flexible substrate.

  5. Item 4. The method for forming a photoresist pattern according to Item 4, wherein the substrate is a polymer substrate.

  6. In the item 5, the polymer substrate is made of polyethersulfone (PES; polyethersulphone), polyacrylate (PAR; polyacrylate), polyetherimide (PEI; polyetherimide), polyethylene naphthalate (PEN; polyethylene naphthalate), polyethylene terephthalate (polyethylene terephthalate). PET; polyethylene terephthalate, polyphenylene sulfide (PPS), polyallylate (polyallylate), polyimide (polyimide), polycarbonate (PC; polycarbonate), cellulose triacetate (TAC), and cellulose acetate propionate (CAP; cellulose acetate) A method of forming a photoresist pattern, wherein the substrate is formed of at least one polymer selected from the group consisting of propionate).

  7. In the above item 1, the photoresist pattern is a negative photoresist, wherein the photoresist pattern is a negative photoresist.

  8. In the above item 1, a photoresist pattern forming method, further comprising performing a pre-bake step after the film forming step and before the exposing step.

  9. The method of claim 1, wherein a post-bake process is performed or not performed after the additional exposure process.

  10. In the above item 1, a photoresist pattern forming method, wherein a post-bake step is performed after the development step and before the additional exposure step.

  11. In the above item 1, the photoresist pattern comprises a pattern selected from the group consisting of an array flattening film pattern, a protective film pattern, an insulating film pattern, a photoresist pattern, a black matrix pattern, and a column spacer pattern. Pattern formation method.

  The method of forming a photoresist pattern according to the present invention can form a photoresist pattern having high reliability such as chemical resistance and heat resistance without performing a heat treatment step, for example, a post-baking step after development.

  Therefore, the method of forming a photoresist pattern according to the present invention does not require a post-bake process, so that a thermal shock applied to the substrate is small. Further, even when a material more vulnerable to heat is used, a photoresist pattern having excellent reliability can be formed, and therefore, it can be suitably used, for example, in a manufacturing process of a flexible display device.

  The present invention provides a photoresist pattern forming method including a film forming step, an exposing step, and a developing step, wherein an additional exposing step is further performed after the developing step, thereby forming a photoresist pattern that does not require a heat treatment step after the developing step. About.

  Hereinafter, a specific example of the method of forming a photoresist pattern according to the present invention will be described in more detail.

<Film forming process>
The film forming step may be performed by applying a photosensitive resin composition for a photoresist to a substrate.

  As the photosensitive resin composition for a photoresist, those known in the art may be applied without particular limitation. The photosensitive resin composition for a photoresist can be classified into a positive type and a negative type according to a developing method.However, in the case of a positive type, a heat treatment step as a bleaching step after the developing step is often required. On the other hand, in the case of the negative type, the bleaching step is not often required, so that a photosensitive resin composition for a negative type photoresist may be preferably used.

  Specific examples of the photosensitive resin composition for a photoresist that can be used include an alkali-soluble resin (A), a polymerizable monomer compound (B), a photopolymerization initiator (C), and a solvent (D). And a photosensitive resin composition for a photoresist.

Alkali-soluble resin (A)
The alkali-soluble resin (A) used in the present invention is a component that imparts solubility to an alkali developing solution used in a development processing step for forming a pattern, and is a carboxyl-containing ethylenically unsaturated monomer. And is polymerized.

  The type of the ethylenically unsaturated monomer having a carboxy group is not particularly limited, for example, monocarboxylic acids such as acrylic acid, methacrylic acid, crotonic acid; dicarboxylic acids such as fumaric acid, mesaconic acid, and itaconic acid And anhydrides thereof; ω-carboxypolycaprolactone mono (meth) acrylate and the like, and mono (meth) acrylates of a polymer having a carboxy group and a hydroxyl group at both terminals, and the like, preferably acrylic acid and methacrylic acid. May be. These can be used alone or in combination of two or more.

  The alkali-soluble resin (A) according to the present invention may be obtained by further polymerizing at least one other monomer copolymerizable with the monomer. For example, styrene, vinyltoluene, methylstyrene, p-chlorostyrene, o-methoxystyrene, m-methoxystyrene, p-methoxystyrene, o-vinylbenzyl methyl ether, m-vinylbenzyl methyl ether, p-vinylbenzyl methyl ether Aromatic vinyl compounds such as o-vinylbenzyl glycidyl ether, m-vinylbenzyl glycidyl ether, p-vinylbenzyl glycidyl ether; N-cyclohexylmaleimide, N-benzylmaleimide, N-phenylmaleimide, and N-o-hydroxyphenylmaleimide , Nm-hydroxyphenylmaleimide, Np-hydroxyphenylmaleimide, No-methylphenylmaleimide, Nm-methylphenylmaleimide, Np-methylphenylmaleimide N-substituted maleimide compounds such as No-methoxyphenylmaleimide, Nm-methoxyphenylmaleimide, Np-methoxyphenylmaleimide; methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) Alkyl (meth) acrylates such as acrylate, i-propyl (meth) acrylate, n-butyl (meth) acrylate, i-butyl (meth) acrylate, sec-butyl (meth) acrylate, and t-butyl (meth) acrylate; Cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-methylcyclohexyl (meth) acrylate, tricyclo [5.2.1.02,6] dec-8-yl (meth) acrylate, 2-dicyclopentanyloxy Ethyl (meth) acryl And alicyclic (meth) acrylates such as isobornyl (meth) acrylate; aryl (meth) acrylates such as phenyl (meth) acrylate and benzyl (meth) acrylate; 3- (methacryloyloxymethyl) oxetane; (Methacryloyloxymethyl) -3-ethyloxetane, 3- (methacryloyloxymethyl) -2-trifluoromethyloxetane, 3- (methacryloyloxymethyl) -2-phenyloxetane, 2- (methacryloyloxymethyl) oxetane, 2- Unsaturated oxetane compounds such as (methacryloyloxymethyl) -4-trifluoromethyloxetane; glycidyl (meth) acrylate, 3,4-epoxycyclohexyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (methyl (T) Unsaturated oxirane compounds such as acrylate and methylglycidyl (meth) acrylate; and (meth) acrylates substituted with a cycloalkane, dicycloalkane or tricycloalkane ring having 4 to 16 carbon atoms. These can be used alone or in combination of two or more.

  The alkali-soluble resin (A) preferably has an acid value in the numerical range of 20 to 200 (KOH mg / g). When the acid value is in the above numerical range, it becomes possible to manufacture a spacer having excellent stability over time and elastic recovery.

  The weight average molecular weight in terms of polystyrene of the alkali-soluble resin (A) is from 3,000 to 100,000, preferably from 5,000 to 50,000. It is preferable that the weight-average molecular weight of the alkali-soluble resin is within the above-mentioned numerical range, because the reduction of the film during development is suppressed and the dropout property of the pattern portion is improved.

  The molecular weight distribution [weight average molecular weight (Mw) / number average molecular weight (Mn)] of the alkali-soluble resin (A) is preferably from 1.5 to 6.0, and more preferably from 1.8 to 4.0. More preferred. It is preferable that the molecular weight distribution [weight average molecular weight (Mw) / number average molecular weight (Mn)] is within the above numerical range, since the developability is excellent.

  The content of the alkali-soluble resin (A) is not particularly limited. For example, based on solid powder, 10 to 90 parts by mass, preferably 25 to 70 parts by mass, based on 100 parts by mass of the photosensitive resin composition. May be included in quantity. When it is included in the above numerical range, the solubility in a developer is sufficient, so that the developability is good, and a photocured pattern having an excellent elastic recovery rate and a small total displacement can be formed.

Polymerizable compound (B)
The polymerizable compound (B) used in the photosensitive resin composition of the present invention is a monofunctional monomer, a difunctional monomer, or another polyfunctional monomer, and the type thereof is not particularly limited. The following compounds are mentioned as examples.

  Specific examples of the monofunctional monomer include nonylphenyl carbitol acrylate, 2-hydroxy-3-phenoxypropyl acrylate, 2-ethylhexyl carbitol acrylate, 2-hydroxyethyl acrylate, N-vinylpyrrolidone, and the like. Specific examples of the bifunctional monomer include 1,6-hexanediol di (meth) acrylate, ethylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, Bis (acryloyloxyethyl) ether of bisphenol A, 3-methylpentanediol di (meth) acrylate and the like can be mentioned. Specific examples of other polyfunctional monomers include trimethylolpropane tri (meth) acrylate, ethoxylated trimethylolpropane tri (meth) acrylate, propoxylated trimethylolpropane tri (meth) acrylate, pentaerythritol tri ( (Meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, ethoxylated dipentaerythritol hexa (meth) acrylate, propoxylated dipentaerythritol hexa (meth) acrylate, dipentaerythritol hexa (meth) acrylate A) acrylate and the like. Among these, a bifunctional or higher functional monomer is preferably used.

  The content of the polymerizable compound (B) is not particularly limited. For example, based on the solid powder in the photosensitive resin composition, 10 to 90 parts by mass based on 100 parts by mass of the alkali-soluble resin and the polymerizable compound in total. It is used in an amount of 30 parts by mass, preferably 30 to 80 parts by mass. When the polymerizable compound (B) is contained in the above content range, a cured pattern having an excellent elastic recovery rate and a small total displacement can be formed, and the developability of the composition can be improved.

Photopolymerization initiator (C)
The photopolymerization initiator (C) according to the present invention can be used without particular limitation as long as it can polymerize the polymerizable compound (B). For example, an acetophenone-based compound, benzophenone Compound, a triazine compound, a biimidazole compound, a thioxanthone compound, and at least one compound selected from the group consisting of oxime ester compounds, and preferably an oxime ester compound is used. .

  Specific examples of the acetophenone-based compound include diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzyldimethylketal, and 2-hydroxy-1- [4- (2-hydroxyethoxy). Phenyl] -2-methylpropan-1-one, 1-hydroxycyclohexylphenyl ketone, 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino- 1- (4-morpholinophenyl) butan-1-one, 2-hydroxy-2-methyl-1- [4- (1-methylvinyl) phenyl] propan-1-one, 2- (4-methylbenzyl)- 2- (dimethylamino) -1- (4-morpholinophenyl) butan-1-one and the like.

  Specific examples of the benzophenone-based compound include benzophenone, methyl o-benzoylbenzoate, 4-phenylbenzophenone, 4-benzoyl-4′-methyldiphenylsulfide, 3,3 ′, 4,4′-tetra (tert-butyl) Peroxycarbonyl) benzophenone, 2,4,6-trimethylbenzophenone and the like.

  Specific examples of the triazine-based compound include 2,4-bis (trichloromethyl) -6- (4-methoxyphenyl) -1,3,5-triazine and 2,4-bis (trichloromethyl) -6- ( 4-methoxynaphthyl) -1,3,5-triazine, 2,4-bis (trichloromethyl) -6-piperonyl-1,3,5-triazine, 2,4-bis (trichloromethyl) -6- (4 -Methoxystyryl) -1,3,5-triazine, 2,4-bis (trichloromethyl) -6- [2- (5-methylfuran-2-yl) ethenyl] -1,3,5-triazine, , 4-Bis (trichloromethyl) -6- [2-furan-2-yl) ethenyl] -1,3,5-triazine, 2,4-bis (trichloromethyl) -6- [2- (4-diethylamino) -2-methylfe Le) ethenyl] -1,3,5-triazine, 2,4-bis (trichloromethyl) -6- [2- (3,4-dimethoxyphenyl) ethenyl] -1,3,5-triazine and the like. .

  Specific examples of the biimidazole compound include 2,2′-bis (2-chlorophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole and 2,2′-bis (2,3-dichlorophenyl). ) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (2-chlorophenyl) -4,4 ′, 5,5′-tetra (alkoxyphenyl) biimidazole, 2,2 '-Bis (2-chlorophenyl) -4,4', 5,5'-tetra (trialkoxyphenyl) biimidazole, 2,2-bis (2,6-dichlorophenyl) -4,4'5,5'- Examples include tetraphenyl-1,2'-biimidazole or an imidazole compound in which the phenyl group at the 4,4 ', 5,5'-position is substituted with a carboalkoxy group, and preferably 2,2'-bis (2 − (Rolophenyl) -4,4 ', 5,5'-tetraphenylbiimidazole, 2,2'-bis (2,3-dichlorophenyl) -4,4', 5,5'-tetraphenylbiimidazole, 2,2 -Bis (2,6-dichlorophenyl) -4,4'5,5'-tetraphenyl-1,2'-biimidazole and the like.

  Specific examples of the thioxanthone-based compound include 2-isopropylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone, 1-chloro-4-propoxythioxanthone, and the like.

  Specific examples of the oxime ester-based compound include o-ethoxycarbonyl-α-oximino-1-phenylpropan-1-one, 1,2-octadion-1- (4-phenylthio) phenyl-2- (o-benzoyl). ) Oxime, ethanone-1- (9-ethyl) -6- (2-methylbenzoyl-3-yl) -1- (o-acetyloxime) and the like, and as a commercial product, CGI-124 (Ciba-Geigy) , CGI-224 (Ciba-Geigy), Irgacure OXE-01 (BASF), Irgacure OXE-02 (BASF), N-1919 (Adeka), NCI-831 (Adeka) and the like.

  Further, the photopolymerization initiator (C) may further include a photopolymerization initiation aid in order to improve the sensitivity of the photosensitive resin composition of the present invention. Since the photosensitive resin composition according to the present invention contains a photopolymerization initiation assistant, the sensitivity can be further increased, and the productivity can be improved.

  Examples of the photopolymerization initiation aid include at least one compound selected from the group consisting of an amine compound, a carboxylic acid compound, and an organic sulfur compound having a thiol group.

  Specific examples of the amine compound include aliphatic amine compounds such as triethanolamine, methyldiethanolamine, and triisopropanolamine, methyl 4-dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, 2-Ethylhexyl 4-dimethylaminobenzoate, (2-dimethylamino) ethyl benzoate, N, N-dimethylparatoluidine, 4,4′-bis (dimethylamino) benzophenone (commonly known as Michler's ketone), 4,4 ′ -Bis (diethylamino) benzophenone and the like, and it is preferable to use an aromatic amine compound.

  Specific examples of the carboxylic acid compound are preferably aromatic heteroacetic acids, such as phenylthioacetic acid, methylphenylthioacetic acid, ethylphenylthioacetic acid, methylethylphenylthioacetic acid, dimethylphenylthioacetic acid, and methoxyphenylthioacetic acid. Examples include acetic acid, dimethoxyphenylthioacetic acid, chlorophenylthioacetic acid, dichlorophenylthioacetic acid, N-phenylglycine, phenoxyacetic acid, naphthylthioacetic acid, N-naphthylglycine, and naphthoxyacetic acid.

  Specific examples of the organic sulfur compound having a thiol group include 2-mercaptobenzothiazole, 1,4-bis (3-mercaptobutyryloxy) butane, 1,3,5-tris (3-mercaptobutyloxyethyl) -1,3,5-triazine-2,4,6 (1H, 3H, 5H) -trione, trimethylolpropane tris (3-mercaptopropionate), pentaerythritol tetrakis (3-mercaptobutyrate), pentaerythritol Examples thereof include tetrakis (3-mercaptopropionate), dipentaerythritol hexakis (3-mercaptopropionate), and tetraethylene glycol bis (3-mercaptopropionate).

  The content of the photopolymerization initiator (C) is not particularly limited. For example, the content is 0.1 to 10 parts by mass based on 100 parts by mass of the photosensitive resin composition based on solid powder. And preferably in an amount of 0.1 to 5 parts by mass. When the above numerical range is satisfied, since the exposure time is shortened by increasing the sensitivity of the photosensitive resin composition, the productivity can be improved and a high resolution can be maintained. Is preferable in that the surface has good smoothness.

Solvent (D)
The solvent (D) can be used without any limitation as long as it is commonly used in the art.

  Specific examples of the solvent include ethylene glycol monoalkyl ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, and ethylene glycol monobutyl ether; diethylene glycol dimethyl ether, diethylene glycol diethyl ether, and diethylene glycol. Diethylene glycol dialkyl ethers such as ethyl methyl ether, diethylene glycol dipropyl ether and diethylene glycol dibutyl ether; ethylene glycol alkyl ether ethers such as methyl cellosolve acetate, ethyl cellosolve acetate, ethylene glycol monobutyl ether acetate and ethylene glycol monoethyl ether acetate; Tates; propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, methoxybutyl acetate, methoxypentyl acetate, and other alkylene glycol alkyl ether acetates; propylene glycol monomethyl ether, propylene glycol monoethyl ether; Propylene glycol monoalkyl ethers such as propylene glycol monopropyl ether and propylene glycol monobutyl ether; propylene glycol dimethyl ether, propylene glycol diethyl ether, propylene glycol ethyl methyl ether, propylene glycol dipropyl ether, propylene glycol propyl ether Propylene glycol dialkyl ethers such as propylene glycol methyl ether propionate, propylene glycol ethyl ether propionate, propylene glycol propyl ether propionate, propylene glycol butyl ether propionate, etc. Ether propionates; butyldiol monoalkyl ethers such as methoxybutyl alcohol, ethoxybutyl alcohol, propoxybutyl alcohol, butoxybutyl alcohol; butanediol monoalkyl such as methoxybutyl acetate, ethoxybutyl acetate, propoxybutyl acetate, butoxybutyl acetate; Alkyl ether acetates; Butanediol monoalkyl ether propionates such as cibutylpropionate, ethoxybutylpropionate, propoxybutylpropionate, butoxybutylpropionate; dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether, dipropylene glycol methyl Dipropylene glycol dialkyl ethers such as ethyl ether; aromatic hydrocarbons such as benzene, toluene, xylene and mesitylene; ketones such as methyl ethyl ketone, acetone, methyl amyl ketone, methyl isobutyl ketone and cyclohexanone; ethanol, propanol, butanol, Alcohols such as hexanol, cyclohexanol, ethylene glycol, and glycerin; methyl acetate, ethyl acetate, propyl acetate, and vinegar Butyl, ethyl 2-hydroxypropionate, methyl 2-hydroxy-2-methylpropionate, ethyl 2-hydroxy-2-methylpropionate, methyl hydroxyacetate, ethyl hydroxyacetate, butyl hydroxyacetate, methyl lactate, ethyl lactate, lactic acid Propyl, butyl lactate, methyl 3-hydroxypropionate, ethyl 3-hydroxypropionate, propyl 3-hydroxypropionate, butyl 3-hydroxypropionate, methyl 2-hydroxy-3-methylbutanoate, methyl methoxyacetate, ethyl methoxyacetate , Propyl methoxyacetate, butyl methoxyacetate, methyl ethoxyacetate, ethyl ethoxyacetate, propyl ethoxyacetate, butyl ethoxyacetate, methyl propoxyacetate, ethyl propoxyacetate, propylpropoxyacetate, Butyl oxyacetate, methyl butoxyacetate, ethyl butoxyacetate, propyl butoxyacetate, butyl butoxyacetate, methyl 2-methoxypropionate, ethyl 2-methoxypropionate, propyl 2-methoxypropionate, butyl 2-methoxypropionate, 2- Methyl ethoxypropionate, ethyl 2-ethoxypropionate, propyl 2-ethoxypropionate, butyl 2-ethoxypropionate, methyl 2-butoxypropionate, ethyl 2-butoxypropionate, propyl 2-butoxypropionate, 2-butoxy Butyl propionate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, propyl 3-methoxypropionate, butyl 3-methoxypropionate, methyl 3-ethoxypropionate, 3-ethoxyp Ethyl lopionate, propyl 3-ethoxypropionate, butyl 3-ethoxypropionate, methyl 3-propoxypropionate, ethyl 3-propoxypropionate, propyl 3-propoxypropionate, butyl 3-propoxypropionate, 3-butoxypropione Esters such as methyl acrylate, ethyl 3-butoxypropionate, propyl 3-butoxypropionate and butyl 3-butoxypropionate; cyclic ethers such as tetrahydrofuran and pyran; cyclic esters such as γ-butyrolactone. The solvents listed here can be used alone or in combination of two or more.

  In consideration of coatability and drying property, the solvent is selected from alkylene glycol alkyl ether acetates, ketones, butanediol alkyl ether acetates, butanediol monoalkyl ethers, ethyl 3-ethoxypropionate, and methyl 3-methoxypropionate. Esters such as propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, cyclohexanone, methoxybutyl acetate, methoxybutanol, ethyl 3-ethoxypropionate, and methyl 3-methoxypropionate. May be used.

  The content of the solvent (D) may be included in an amount of 40 to 95 parts by mass, preferably 45 to 85 parts by mass, based on 100 parts by mass of the entire photosensitive resin composition. When the above range is satisfied, the coatability becomes good when applied with a coater such as a spin coater, a slit and spin coater, a slit coater (sometimes referred to as a “die coater” or a “curtain flow coater”), or an inkjet. Therefore, it is preferable.

Additive (E)
The photosensitive resin composition according to the present invention may contain, if necessary, a filler, another polymer compound, a curing agent, a leveling agent, an adhesion promoter, an antioxidant, an ultraviolet absorber, a coagulation inhibitor, a chain transfer agent, and the like. May be further included.

  Specific examples of the filler include glass, silica, and alumina.

  Specific examples of the other polymer compound include curable resins such as epoxy resin and maleimide resin; and thermoplastic resins such as polyvinyl alcohol, polyacrylic acid, polyethylene glycol monoalkyl ether, polyfluoroalkyl acrylate, polyester, and polyurethane. Resins.

  The curing agent is used for deep curing and increasing mechanical strength, and specific examples of the curing agent include an epoxy compound, a polyfunctional isocyanate compound, a melamine compound, and an oxetane compound.

  Specific examples of the epoxy compound as the curing agent include bisphenol A epoxy resin, hydrogenated bisphenol A epoxy resin, bisphenol F epoxy resin, hydrogenated bisphenol F epoxy resin, novolac epoxy resin, and other aromatic compounds. Group-based epoxy resin, alicyclic-based epoxy resin, glycidyl ester-based resin, glycidylamine-based resin, or bromo derivative of such epoxy resin, aliphatic resin, alicyclic or aromatic epoxy other than epoxy resin and its bromo derivative Compound, butadiene (co) polymer epoxy compound, isoprene (co) polymer epoxy compound, glycidyl (meth) acrylate (co) polymer, triglycidyl isocyanurate, and the like.

  Specific examples of the oxetane compound as the curing agent include carbonate bisoxetane, xylene bisoxetane, adipate bisoxetane, terephthalate bisoxetane, and bisoxetane cyclohexanedicarboxylate.

  As the curing agent, a curing auxiliary compound capable of ring-opening polymerizing the epoxy group of the epoxy compound and the oxetane skeleton of the oxetane compound can be used together with the curing agent. Examples of the curing auxiliary compound include polycarboxylic acids, polycarboxylic anhydrides, and acid generators.

  As the carboxylic anhydrides, those commercially available as epoxy resin curing agents can be used. Examples of the epoxy resin curing agent include Adeka Hardener EH-700 (trade name, manufactured by Adeka Industry Co., Ltd.), Rikashid HH (trade name, manufactured by Shin Nippon Rika Co., Ltd.), and MH-700 (trade name, Nippon Rika Co., Ltd.) Co., Ltd.). The curing agents exemplified above can be used alone or in combination of two or more.

  As the leveling agent, commercially available surfactants can be used, for example, silicone-based, fluorine-based, ester-based, cationic, anionic, nonionic, amphoteric surfactants, and the like. Each may be used alone or in combination of two or more.

  Examples of the surfactant include polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyethylene glycol diesters, sorbitan fatty acid esters, fatty acid-modified polyesters, tertiary amine-modified polyurethanes, and polyethylene imines Other than the above, KP (manufactured by Shin-Etsu Chemical Co., Ltd.), Polyflow (manufactured by Kyoei Chemical Co., Ltd.), F-Top (manufactured by Tochem Products Co., Ltd.), Megafac (Dai Nippon Ink Chemical Industry Co., Ltd.) ), Florard (manufactured by Sumitomo 3M Limited), Asahi Guard, Surflon (all manufactured by Asahi Glass Co., Ltd.), Solsperse (manufactured by Zeneca Corporation), EFKA (manufactured by EFKA CHEMICALS), PB821 (Ajinomoto Co., Ltd.) Manufactured).

  As the adhesion promoter, a silane compound is preferable, and specifically, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (2-methoxyethoxy) silane, N- (2-aminoethyl) -3-aminopropyl Methyldimethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2 -(3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-chloropropylmethyldimethoxysilane, 3-chloropropyltrimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, and the like. Is .

  Specific examples of the antioxidant include 2-tert-butyl-6- (3-tert-butyl-2-hydroxy-5-methylbenzyl) -4-methylphenyl acrylate and 2- [1- (2- Hydroxy-3,5-di-tert-pentylphenyl) ethyl] -4,6-di-tert-pentylphenyl acrylate, 6- [3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propoxy ] -2,4,8,10-Tetra-tert-butyldibenz [d, f] [1,3,2] dioxaphosphepin, 3,9-bis [2- {3- (3-tert-butyl) -4-hydroxy-5-methylphenyl) propionyloxy} -1,1-dimethylethyl] -2,4,8,10-tetraoxaspiro [5.5] undecane, 2,2′-methyl Lenbis (6-tert-butyl-4-methylphenol), 4,4'-butylidenebis (6-tert-butyl-3-methylphenol), 4,4'-thiobis (2-tert-butyl-5-methylphenol) ), 2,2'-thiobis (6-tert-butyl-4-methylphenol), dilauryl-3,3'-thiodipropionate, dimyristyl-3,3'-thiodipropionate, distearyl-3, 3′-thiodipropionate, pentaerythrityltetrakis (3-laurylthiopropionate), 1,3,5-tris (3,5-di-tert-butyl-4-hydroxybenzyl) -1,3,3 5-triazine-2,4,6 (1H, 3H, 5H) -trione, 3,3 ′, 3 ″, 5,5 ′, 5 ″ -hexa-tert-butyl-a a ′, a ″-(mesitylene-2,4,6-triyl) tri-p-cresol, pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 2 , 6-di-tert-butyl-4-methylphenol and the like.

  Specific examples of the ultraviolet absorber include 2- (3-tert-butyl-2-hydroxy-5-methylphenyl) -5-chlorobenzotriazole and alkoxybenzophenone.

  Specific examples of the aggregation preventing agent include sodium polyacrylate.

  Specific examples of the chain transfer agent include dodecyl mercaptan, 2,4-diphenyl-4-methyl-1-pentene, and the like.

  The method for applying the photosensitive resin composition for a photoresist is not particularly limited, and may be, for example, spin coating, casting coating, roll coating, slit-and-spin coating, slit coating, or the like.

  The substrate on which the photosensitive resin composition for photoresist is applied is not particularly limited as long as it can form a photoresist pattern, and may be, for example, a glass or polymer substrate. In a further aspect, the substrate may be a flexible substrate, in which case the polymer substrate described above may be used.

  Examples of the polymer substrate include polyethersulfone (PES; polyethersulphone), polyacrylate (PAR; polyacrylate), polyetherimide (PEI; polyetherimide), polyethylene naphthalate (PEN; polyethylene naphthalate), and polyethylene terephthalate (PET; polyethylene). terephthalate), polyphenylene sulfide (PPS), polyallylate (polyallylate), polyimide (polyimide), polycarbonate (PC), cellulose triacetate (TAC), cellulose acetate propionate (CAP), etc. Are used alone, or a substrate manufactured from a polymer obtained by mixing two or more kinds thereof, but the present invention is not limited thereto.

  Further, the substrate may be further provided with a separate layer for forming a pattern on the substrate by photolithography. Examples of such a layer include a conductive layer, and the conductive layer may be formed of a metal, a metal oxide, a carbon-based material, or the like.

  After the film forming step of applying the photosensitive resin composition to the substrate, a heat treatment step (pre-bake) may be further performed. Through such a heat treatment step, volatile components such as a residual solvent are removed. The heat treatment temperature is about 70-200C, preferably 80-130C. The thickness of the coating film after the heat treatment step may be about 1 to 8 μm.

<Exposure process>
After the completion of the film forming process, light is irradiated through a mask for forming a desired pattern, and an exposure process for promoting curing of the irradiated portion is performed.

  At the time of the exposure step, it is preferable to use a device such as a mask aligner or a stepper so that the entire exposed portion is uniformly irradiated with parallel rays and the mask and the substrate are accurately aligned.

  The light to be used is not particularly limited as long as the light can cure the photosensitive resin composition, and a representative example is ultraviolet light.

As the ultraviolet rays, g-rays (wavelength: 436 nm), h-rays, i-rays (wavelength: 365 nm) and the like can be used. The irradiation amount of the ultraviolet ray can be appropriately selected as needed, and is not limited in the present invention. For example, the energy used in the irradiation of the ultraviolet ray is about 40 cm ² per unit area (cm ² ). It may be about 70 mJ.

<Development process>
After the curing is completed, if necessary, the coating film is brought into contact with a developing solution, and the unexposed portion is dissolved and developed to perform a developing step of forming a desired pattern shape.

  As the development method, any of a liquid addition method, a dipping method, a spray method, and the like may be used. Further, the substrate may be inclined at an arbitrary angle during development. The developer is usually an aqueous solution containing an alkaline compound and a surfactant. The alkaline compound may be any of inorganic and organic alkaline compounds. Specific examples of the inorganic alkaline compound include sodium hydroxide, potassium hydroxide, disodium hydrogen phosphate, sodium dihydrogen phosphate, diammonium hydrogen phosphate, ammonium dihydrogen phosphate, potassium dihydrogen phosphate, silica Sodium acid, potassium silicate, sodium carbonate, potassium carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate, sodium borate, potassium borate, ammonia and the like. Further, specific examples of the organic alkaline compound include tetramethylammonium hydroxide, 2-hydroxyethyltrimethylammonium hydroxide, monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, Ethanolamine and the like can be mentioned.

  These inorganic and organic alkaline compounds can be used alone or in combination of two or more. The concentration of the alkaline compound in the alkaline developer is preferably from 0.01 to 10% by mass, more preferably from 0.03 to 5% by mass.

  As the surfactant in the alkali developer, at least one selected from the group consisting of a nonionic surfactant, an anionic surfactant, and a cationic surfactant can be used.

  Specific examples of the nonionic surfactant include polyoxyethylene alkyl ether, polyoxyethylene aryl ether, polyoxyethylene alkyl aryl ether, other polyoxyethylene derivatives, oxyethylene / oxypropylene block copolymer, Examples include sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene sorbitol fatty acid esters, glycerin fatty acid esters, polyoxyethylene fatty acid esters, polyoxyethylene alkylamines, and the like.

  Specific examples of the anionic surfactant include higher alcohol sulfates such as sodium lauryl alcohol sulfate and sodium oleyl alcohol sulfate; alkyl sulfates such as sodium lauryl sulfate and ammonium lauryl sulfate; and sodium dodecylbenzene sulfonate. And alkylaryl sulfonates such as sodium dodecylnaphthalenesulfonate.

  Specific examples of the cationic surfactant include amine salts such as stearylamine hydrochloride and lauryltrimethylammonium chloride, and quaternary ammonium salts. These surfactants can be used alone or in combination of two or more.

  The concentration of the surfactant in the developer is generally from 0.01 to 10% by mass, preferably from 0.05 to 8% by mass, more preferably from 0.1 to 5% by mass.

<Additional exposure step>
In the present invention, an additional exposure step is performed after the development step.

  The additional exposure step in the present invention is a step of irradiating the formed photoresist pattern with light again after the development step. By increasing the degree of curing of the photoresist pattern formed by such an additional exposure step, reliability of the pattern such as heat resistance and chemical resistance can be improved.

  The additional exposure step in the present invention may use the light used in the exposure step before the development step in the same manner, and is preferably performed at 4 to 20 times the energy of the exposure step before the development step. Good. By irradiating light with the energy in the above numerical range, the reliability of the pattern can be further improved.

  The additional exposure step in the present invention may be performed by irradiating light only on a pattern formed using a mask in the same manner as the exposure step before the development step, or may be performed by full-surface exposure without a mask, In consideration of productivity, the entire surface exposure is preferable.

  According to the photoresist pattern forming method of the present invention, a pattern having required reliability can be formed without performing a general heat treatment step (post-bake) after the developing step. However, this does not exclude the heat treatment step (post-bake) after the development step in the present invention. In the present invention, the degree of curing can be further improved by performing a heat treatment step (post-bake) after the development step, if necessary. The post-bake process may be performed at 80 to 230C for 10 to 90 minutes.

  In another embodiment of the present invention, when performing the post-bake process, the additional exposure process may be performed after the post-bake process.

  Photoresist patterns that can be formed by the present invention include various patterns in an image display device, such as an array flattening film pattern, a protection pattern, in addition to a general photoresist pattern that is removed after being formed during a photolithography process. It may be a film pattern, an insulating film pattern, a black matrix pattern, a column spacer pattern, or the like, but is not limited thereto.

  Hereinafter, preferred embodiments will be described to facilitate understanding of the present invention. However, these embodiments are merely illustrative of the present invention, and do not limit the scope of the appended claims. It will be apparent to those skilled in the art that various changes and modifications can be made to the embodiments within the scope and spirit of the present invention, and such changes and modifications are set forth in the appended claims. It goes without saying that it belongs to

Synthesis Example 1: Synthesis of alkali-soluble resin (A-1) A 1- L flask equipped with a reflux condenser, a dropping funnel, and a stirrer was placed under a nitrogen atmosphere, and 300 parts by mass of methylethyldiethylene glycol was added. Until heated. Next, 300 parts by mass of a mixture of the following chemical formulas 1 and 2 (molar ratio 50:50), 100 parts by mass of glycidyl methacrylate, and 50 parts by mass of methacrylic acid were dissolved in 140 parts by mass of methyl ethyl diethylene glycol to prepare a solution.

調製した溶液を、滴下漏斗を用いて４時間かけて７０℃に保温したフラスコ内に滴下した。その一方で、重合開始剤２，２’−アゾビス（２，４−ジメチルバレロニトリル）３０質量部をメチルエチルジエチレングリコール２２５質量部に溶解させて調製した溶液を、別の滴下漏斗を用いて４時間かけてフラスコ内に滴下した。重合開始剤の溶液の滴下が終了した後、４時間、７０℃に維持し、その後に室温まで冷却させ、固形粉３６．７質量％、酸価５９ｍｇ−ＫＯＨ／ｇ（固形粉換算）の共重合体（Ａ−１）の溶液を得た。

The prepared solution was dropped into a flask kept at 70 ° C. over 4 hours using a dropping funnel. On the other hand, a solution prepared by dissolving 30 parts by mass of a polymerization initiator 2,2′-azobis (2,4-dimethylvaleronitrile) in 225 parts by mass of methyl ethyl diethylene glycol was used for another 4 hours using another dropping funnel. The mixture was dropped into the flask. After completion of the dropwise addition of the polymerization initiator solution, the temperature was maintained at 70 ° C. for 4 hours, and then cooled to room temperature, and 36.7% by mass of solid powder and an acid value of 59 mg-KOH / g (as solid powder) were used. A solution of the polymer (A-1) was obtained.

  The weight average molecular weight (Mw) of the obtained resin A-1 was 8,200, and the molecular weight distribution was 1.85.

  At this time, the weight average molecular weight (Mw) and the number average molecular weight (Mn) of the dispersion resin were measured using an HLC-8120GPC (manufactured by Tosoh Corporation), and the columns were TSK-GELG4000HXL and TSK-GELG2000HXL in series. The column temperature was 40 ° C., the mobile phase solvent was tetrahydrofuran, the flow rate was 1.0 mL / min, the injection volume was 50 μL, the detector was RI, and the measurement sample concentration was 0.6% by mass (solvent = tetrahydrofuran). ), TSK STANDARD POLYSTYRENE F-40, F-4, F-1, A-2500, A-500 (manufactured by Tosoh Corporation) were used as calibration standard substances.

  The ratio between the obtained weight average molecular weight and number average molecular weight was defined as a molecular weight distribution (Mw / Mn).

Synthesis Example 2: Synthesis of alkali-soluble resin (A-2) Nitrogen was introduced into a 1-L flask equipped with a reflux condenser, a dropping funnel, and a stirrer under a nitrogen atmosphere by flowing 0.02 L / min. 200 parts by mass of -methoxy-1-butanol and 105 parts by mass of 3-methoxybutyl acetate were charged, and the mixture was heated to 70 ° C with stirring. Next, 240 parts by mass of a mixture of formulas 1 and 2 (molar ratio 50:50), 60 parts by mass of methacrylic acid, and 140 parts by mass of 3-methoxybutyl acetate were dissolved to prepare a solution.

  The prepared solution was dropped into a flask kept at 70 ° C. over 4 hours using a dropping funnel. On the other hand, a solution prepared by dissolving 30 parts by mass of a polymerization initiator 2,2′-azobis (2,4-dimethylvaleronitrile) in 225 parts by mass of 3-methoxybutyl acetate was used for another dropping funnel. The solution was dropped into the flask over 4 hours. After completion of the dropwise addition of the polymerization initiator solution, the temperature was maintained at 70 ° C. for 4 hours, then cooled to room temperature, and the mixture of solid powder 32.6% by mass and an acid value of 75 mg-KOH / g (solid powder equivalent) was used. A solution of the polymer (A-2) was obtained.

  The weight average molecular weight (Mw) of the obtained resin A-2 was 10,400, and the molecular weight distribution was 2.50. The weight average molecular weight (Mw), number average molecular weight (Mn), and molecular weight distribution of the dispersion resin were the same as in Synthesis Example 1.

Preparation Example 1
A photosensitive resin composition having the composition shown in Table 1 below was prepared (unit: parts by mass).

Preparation Example 2
A photosensitive resin composition was prepared in the same manner as in Preparation Example 1, except that the alkali-soluble resin of Synthesis Example 2 was used.

Examples 1 to 5 and Comparative Examples 1 and 2
A 2-inch square glass substrate (Eagle 2000, manufactured by Corning Incorporated) was sequentially washed with a neutral detergent, water and alcohol, and then dried. After spin-coating the photosensitive resin composition of Preparation Example 1 on this glass substrate, a photoresist pattern was formed in the steps shown in Table 2 below.

Examples 6 to 10 and Comparative Examples 3 to 4
A photoresist pattern was formed in the same manner as in Table 2 except that the photosensitive resin composition of Preparation Example 2 was used.

Test Example The physical properties of the formed photoresist pattern were evaluated as follows, and the results are shown in Table 4 below.

  (1) Hole line width: An average value measured in the X direction and the Y direction of the bottom surface when a Hole pattern is formed.

  (2) CD-Bias: This is a value obtained by subtracting the applied mask size from the manufactured actual pattern size, and the closer the actual pattern size is to the applied mask size, the better the pattern forming performance is. You can judge.

  In this case, a composition having a value close to 0 is determined to be superior.

  (3) Heat resistant residual film rate: The formed coating film is heated at 230 ° C. for further 30 minutes, and the degree of film shrinkage due to additional heating is observed. When the heat resistance is excellent, it is considered that the film shrinkage due to the additional heating is small, and the one having a high heat resistant residual film ratio after the additional heating can be judged to be excellent in the heat resistance.

(4) Evaluation of chemical resistance: The formed coating film is immersed in an aqueous solution of HNO ₃ and HCl and treated for 45 minutes / 6 minutes.

  Thereafter, based on ASTM D-3359-08 standard test conditions, adhesion was confirmed by a method in which a tape was attached to the surface cut with a cutter and then peeled off.

  After performing the chemical treatment, the degree of peeling of the coating film in the Cutting / Tape test is defined as 0B to 5B based on the standard test method, and 5B is determined to have the best performance (5B: peeling 0). %, 4B: peeling less than 5%, 3B: peeling 5 or more to less than 15%, 2B: peeling 15 or more to less than 35%, 1B: peeling 35 or more to less than 65%, 0B: 65% or more).

  (5) Transmittance: The transmittance of the completed coating film is measured.

  Referring to Table 4, in the example in which the additional exposure is performed after the development step, when the post-bake step is not performed (Examples 2, 4, 5, 7, 9, and 10), the post-exposure step is performed after the additional exposure step. Neither the case of performing the bake process (Examples 1 and 6) or the case of performing the post-bake process and performing the additional exposure (Examples 3 and 8), but performing the additional exposure process (Comparative) As compared with Examples 1 and 3), remarkable improvements in heat resistance and chemical resistance were confirmed.

  In the case of Comparative Examples 2 and 4, additional exposure (overall exposure) was performed before development, and it was confirmed that no pattern was formed due to excessive curing of the photoresist. In this case, the reliability evaluation result is a result obtained in a film state.

Claims (8)

In a negative photoresist pattern forming method comprising a film forming step, an exposing step, and a developing step,
Wherein after the development step, further performing additional exposure process using a mask,
A negative photoresist pattern forming method , wherein a post-bake step is performed after the developing step and before the additional exposure step .   2. The method of claim 1, wherein the additional exposing step is performed at 4 to 20 times the energy of the exposing step before the developing step. 3.   The method according to claim 1, wherein the substrate on which the negative photoresist pattern is formed is a flexible substrate.   4. The method of claim 3, wherein the substrate is a polymer substrate.   The polymer substrate is made of polyethersulfone (PES), polyacrylate (PAR; polyacrylate), polyetherimide (PEI), polyethylene naphthalate (PEN), polyethylene terephthalate (PET). , Polyphenylene sulfide (PPS), polyallylate (polyallylate), polyimide (polyimide), polycarbonate (PC), cellulose triacetate (TAC), and cellulose acetate propionate (CAP). The method of claim 4, wherein the substrate is a substrate formed of at least one polymer selected from the group consisting of:   The method of claim 1, further comprising performing a pre-bake step after the film formation step and before the exposure step.   7. The method of claim 1, wherein a post-bake process is performed or not performed after the additional exposure process. The negative type photoresist pattern array flattening film pattern, the protective film pattern, an insulating film pattern, a black matrix pattern, and a pattern selected from the group consisting of column spacers pattern, in any one of claims 1 to 7 The method for forming a negative photoresist pattern as described in the above.