Photosensitive resin composition

Abstract

According to one embodiment of the present invention, the photosensitive resin composition includes, relative to 100 parts by weight of an acrylic copolymer: 0.1 to 20 parts by weight of a free radical photoinitiator; 0.1 to 10 parts by weight of an ionic photoinitiator; 1 to 50 parts by weight of a multifunctional acrylate oligomer; 1 to 50 parts by weight of a multifunctional monomer having an ethylenically unsaturated bond; and a solvent.

Description

Technical Field

[0001] The invention relates to a photosensitive resin composition and a pattern forming method using the composition. Background Art

[0002] Generally, display devices are widely used at present, including liquid crystal display devices (LCD) and organic light emitting display devices (OLED). In addition, recently, display devices that are bent to form a curved surface have attracted attention, which can improve the user's sense of immersion.

[0003] In the process of forming such a display device, a photolithography process may be used to pattern a film, in which case a photoresist is used, or the photoresist may be exposed and developed to directly form a film.

[0004] The above-mentioned photoresist can be used to form an insulating film, a columnar spacer, an overcoat layer, and a color filter layer. The composition of the photosensitive resin composition used to form the photoresist affects the resolution, adhesion, film retention rate, etc. Summary of the invention

[0005] The embodiment provides a photosensitive resin composition that can be cured at low temperature and has excellent sensitivity, film retention rate and residue characteristics, and a pattern forming method using the same.

[0006] According to one embodiment of the present invention, the photosensitive resin composition includes, relative to 100 parts by weight of an acrylic copolymer: 0.1 to 20 parts by weight of a free radical photoinitiator; 0.1 to 10 parts by weight of an ionic photoinitiator; 1 to 50 parts by weight of a multifunctional acrylate oligomer; 1 to 50 parts by weight of a multifunctional monomer having an ethylenically unsaturated bond; and a solvent.

[0007] The photosensitive resin composition may be cured at a temperature below 90° C.

[0008] The free radical photoinitiator may be 2-(O-benzoyloxime)-1-[4-(phenylthio)phenyl]-1,2-octanedione or 2-(O-acetyloxime)-1-[4-(phenylthio)phenyl]-1,2-octanedione.

[0009] The ionic photoinitiator may be one selected from the group consisting of phenyl(4-methoxyphenyl)iodonium phosphorus hexafluoride, N,N-dimethyl-N-benzyltrifluoromethanesulfonic acid, 4-methylphenyl(4-(2-methylpropylphenyl))iodonium phosphorus hexafluoride and phenyl(4-methoxyphenyl)iodonium arsenic hexafluoride.

[0010] The content ratio of the free radical photoinitiator to the ionic photoinitiator may be 2:1 to 1:2.

[0011] The photosensitive resin composition may have a solid content of 10 wt % to 50 wt %.

[0012] The photosensitive resin composition may further include a melamine cross-linking agent.

[0013] The photosensitive resin composition may further include a silane coupling agent.

[0014] The acrylic copolymer may be formed by copolymerizing an unsaturated carboxyl compound and an unsaturated olefin compound.

[0015] The boiling point of the solvent may be less than 150°C.

[0016] According to the embodiment, the photosensitive resin composition and the pattern forming method using the composition have excellent sensitivity and film retention rate, can improve residue characteristics, and have excellent adhesion and chemical resistance in a low-temperature process. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figures 1 to 4 FIG. 4 is a process flow chart showing a pattern forming method according to an embodiment of the present invention.

[0018] Explanation of symbols

[0019] 110: substrate 400: coated photosensitive resin composition

[0020] 410: Photosensitive resin composition layer 700: Mask DETAILED DESCRIPTION

[0021] Hereinafter, multiple embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those with basic knowledge in the technical field to which the present invention belongs can easily implement the present invention. The present invention can be implemented in many different forms and is not limited to the embodiments described herein.

[0022] In order to clearly describe the present invention, parts not related to the description are omitted, and the same or similar components are denoted by the same reference numerals throughout the specification.

[0023] In addition, for the sake of convenience of explanation, the size and thickness of each structure shown in the drawings are illustrated as arbitrary sizes and thicknesses, so the present invention is not necessarily limited to the contents of the drawings. In the drawings, the thickness is enlarged to clearly show multiple layers and regions. Moreover, in the drawings, the thickness of some layers and regions is exaggerated for the sake of convenience of explanation.

[0024] Furthermore, when a part such as a layer, film, region, plate, etc. is described as being “on” or “above” another part, it includes not only the case where it is “directly” located “on” another part, but also the case where there is another part between the two. On the contrary, when a part is described as being “directly” located “on” another part, it means that there is no other part in between. Furthermore, when it is described as being “on” or “above” a part serving as a reference, it means being located above or below the part serving as a reference, and does not necessarily mean being “on” or “above” in the opposite direction of gravity.

[0025] Furthermore, throughout the specification, unless there is an explicit statement to the contrary, when a certain part is mentioned as “including” a certain constituent element, it means that other constituent elements may also be included, and other constituent elements are not excluded.

[0026] Next, the photosensitive resin composition according to one embodiment of the present invention is described. The photosensitive resin composition according to one embodiment of the present invention includes: 0.1 to 20 parts by weight of a free radical photoinitiator; 0.1 to 10 parts by weight of an ion photoinitiator; 1 to 50 parts by weight of a multifunctional acrylate oligomer; 1 to 50 parts by weight of a multifunctional monomer having an ethylenically unsaturated bond; and a solvent, relative to 100 parts by weight of an acrylic copolymer.

[0027] That is, the photosensitive resin composition according to one embodiment of the present invention includes both a free radical photoinitiator and an ion photoinitiator. Therefore, it can be cured at a low temperature below 90°C, and also exhibits excellent adhesion and chemical resistance when cured at a low temperature below 90°C. The photosensitive resin composition according to this embodiment is a negative photosensitive resin as follows: the exposed portion is cured and remains, and the unexposed portion is removed.

[0028] Generally, a temperature of 200° C. or higher is required for curing of a photosensitive resin composition. However, in the case where the photosensitive resin composition is applied as an insulating film of a touch panel integrated with a display device, etc., the characteristics of the light-emitting layer included in the display device may change at a high temperature of 200° C. or higher required for curing the photosensitive resin composition. Therefore, a photosensitive resin composition cured at a high temperature of 200° C. or higher cannot be applied to an insulating film formed by a process continuous with the light-emitting layer, and a process of laminating the composition after manufacturing the insulating film by a separate process is required.

[0029] However, the photosensitive resin composition according to this embodiment includes both a radical photoinitiator and an ion photoinitiator, and can be cured at a low temperature below 90° C., so it can be used as an insulating film manufactured in a process continuous with the light-emitting layer. Therefore, the number of masks in the manufacturing process can be reduced.

[0030] Furthermore, the insulating film etc. manufactured using the photosensitive composition of this embodiment is an organic film, and therefore is more suitable for application in a flexible display device than the insulating film etc. including conventional inorganic substances. Furthermore, chemical vapor deposition (CVD), dry etching, and stripping steps etc. required in the process of manufacturing the insulating film including conventional inorganic substances can be omitted.

[0031] The reason why the photosensitive resin composition of the present invention can be cured at a temperature below 90°C is that it contains both a free radical photoinitiator and an ion photoinitiator. That is, in order to produce a curing reaction, it is necessary to destroy the ring bond and open the ring structure, wherein both the free radical photoinitiator and the ion photoinitiator play a role in destroying the ring, thereby increasing the reaction area and allowing the reaction to proceed actively at a lower temperature.

[0032] At this time, the content ratio of the radical photoinitiator to the ion photoinitiator may be about 2: 1 to 1: 2. The above range is a numerical range that can maximize the adhesion and chemical resistance of the photosensitive resin composition cured at a low temperature.

[0033] In the photosensitive resin composition according to an embodiment of the present invention, the acrylic copolymer can prevent residue from being generated during development, thereby facilitating pattern formation.

[0034] The acrylic copolymer can be formed by copolymerizing an unsaturated carboxyl compound and an unsaturated olefin compound. Specifically, the acrylic copolymer can be obtained by synthesizing i) an unsaturated carboxylic acid, an unsaturated carboxylic acid anhydride or a mixture thereof, and ii) an olefinic unsaturated compound as monomers by free radical reaction in the presence of a solvent and a polymerization initiator, and then removing unreacted monomers through precipitation, filtration, and vacuum drying.

[0035] The unsaturated carboxylic acid, unsaturated carboxylic acid anhydride or mixture thereof used in the present invention may be an unsaturated monocarboxylic acid such as acrylic acid and methacrylic acid, an unsaturated dicarboxylic acid such as maleic acid, fumaric acid, citraconic acid, mesaconic acid, itaconic acid or an unsaturated dicarboxylic acid anhydride, alone or in combination of two or more. In particular, acrylic acid, methacrylic acid or maleic acid is preferred because of its excellent copolymerization reactivity and solubility in an alkaline aqueous solution as a developer.

[0036] The unsaturated carboxylic acid, unsaturated carboxylic acid anhydride or a mixture thereof is preferably contained in an amount of 5 to 40 parts by weight relative to 100 parts by weight of the total monomers. If the content is less than 5 parts by weight, it is difficult to dissolve in an alkaline aqueous solution, and if it exceeds 40 parts by weight, it has a problem of too high solubility in an alkaline aqueous solution.

[0037] The olefinic unsaturated compound used in the present invention can be selected from the group consisting of methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, sec-butyl methacrylate, tert-butyl methacrylate, methyl acrylate, isopropyl acrylate, cyclohexyl acrylate, 2-methylcyclohexyl methacrylate, dicyclopentenyl acrylate, dicyclopentyl acrylate, dicyclopentenyl methacrylate, dicyclopentyl methacrylate, 1-adamantyl acrylate, 1-adamantyl methacrylate, dicyclopentanyloxyethylmethacrylate, isobornyl methacrylate, cyclohexyl acrylate, 2-methylcyclohexyl acrylate, dicyclopentanyloxyethylmethacrylate, isobornyl methacrylate, phenyl methacrylate, phenyl acrylate, benzyl acrylate, 2-hydroxyethyl methacrylate, methacrylate), styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, vinyltoluene, p-methoxystyrene, 1,3-butadiene, isoprene or 2,3-dimethyl-1,3-butadiene, glycidyl acrylate, glycidyl methacrylate, α-ethyl glycidyl acrylate, α-n-propyl glycidyl acrylate, α-n-butyl glycidyl acrylate, β-methyl glycidyl acrylate, β-methyl glycidyl methacrylate, β-ethyl glycidyl acrylate One or more selected from the group consisting of glycerol ester, β-ethyl glycidyl methacrylate, 3,4-epoxybutyl acrylate, 3,4-epoxybutyl methacrylate, 6,7-epoxyheptyl acrylate, 6,7-epoxyheptyl methacrylate, α-ethyl acrylate-6,7-epoxyheptyl ester, o-vinylbenzyl glycidyl ether, m-vinylbenzyl glycidyl ether, p-vinylbenzyl glycidyl ether, and 3,4-epoxycyclohexyl methacrylate, and the above compounds can be used alone or in combination of two or more.

[0038] The olefinic unsaturated compound is preferably contained in an amount of 60 to 95 parts by weight relative to 100 parts by weight of the total monomers. If the content is less than 60 parts by weight, the resolution and heat resistance may be reduced, and if the content exceeds 95 parts by weight, the acrylic copolymer may be difficult to dissolve in an alkaline aqueous solution as a developer.

[0039] As the olefinic unsaturated compound, a monomer including an epoxy group can be used. These monomers can form a dense structure by cross-linking reaction with the aid of an ionic photoinitiator in a low-temperature curing process, thereby improving heat resistance, chemical resistance and physical properties.

[0040] As the solvent used for solution polymerization of the above-mentioned monomers, methanol, tetrahydrofuran, toluene, dioxane, etc. can be used.

[0041] The polymerization initiator used for polymerizing the above-mentioned monomer solution can be a free radical polymerization initiator, specifically, 2,2′-azobisisobutyronitrile, 2,2′-azobis(2,4-dimethylvaleronitrile), 2,2′-azobis(4-methoxy-2,4-dimethylvaleronitrile), 1,1-azobis(cyclohexane-1-carbonitrile) or dimethyl 2,2′-azobis(isobutyric acid) can be used.

[0042] The monomers as described above are subjected to free radical reaction in the presence of a solvent and a polymerization initiator, and unreacted monomers are removed by precipitation, filtration, and vacuum drying processes to manufacture an acrylic copolymer. The polystyrene-converted weight average molecular weight (Mw) of such acrylic copolymers may be 3,000 to 30,000. When the polystyrene-converted weight average molecular weight is less than 3,000, developability, film retention, etc. may decrease, or pattern developability and heat resistance may decrease, and when it exceeds 30,000, pattern developability may deteriorate.

[0043] The photoinitiator used in the photosensitive resin composition of the present invention includes one or more free radical photoinitiators and one or more ion photoinitiators.

[0044] As the free radical photoinitiator, acetophenone compounds such as 4-phenoxydichloroacetophenone, 4-t-butyl-dichloroacetophenone, diethoxyacetophenone, p-dimethylaminoacetophenone, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropane-1-one, 1-hydroxycyclohexylphenyl ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropane-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butane-1-one, 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholino)phenyl]-1-butanone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzyl dimethyl ether, Benzoin compounds such as benzophenone, benzoylbenzoic acid, benzoylbenzoic acid methyl, 4-phenylbenzophenone, hydroxybenzophenone, acrylated benzophenone, 4-benzoyl-4'-methyldiphenyl sulfide, 3,3',4,4'-tetra(t-butylperoxyketo)benzophenone and other benzophenone compounds, thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, isopropylthioxanthone, 2,4-diisopropylthioxanthone, 2,4-diethylthioxanthone and other thioxanthone compounds, 2,4,6-trichloro-s-triazine, 2-phenyl-4,6-bis(trichloromethyl)-s-triazine, 2-(p-methoxyphenyl)-4,6-bis(trichloromethyl)-s-triazine, 2-(p-tolyl)-4,6 -bis(trichloromethyl)-s-triazine, 2-piperonyl-4,6-bis(trichloromethyl)-s-triazine, 2,4-bis(trichloromethyl)-6-phenylvinyl-s-triazine, 2-(naphtho-1-yl)-4,6-bis(trichloromethyl)-s-triazine, 2-(4-methoxy-naphtho-1-yl)-4,6-bis(trichloromethyl)-s-triazine, 2,4-trichloromethyl-(piperonyl)-6-triazine, 2,4-trichloromethyl (4'-methoxyphenylvinyl)-6-triazine and other triazine compounds, 2-(O-benzoyl oxime)-1-[4-(phenylthio)phenyl]-1,2-octanedione, 1-(O-acetyl oxime)-1-[9-ethyl-6-(2-methylbenzoyl)-9 H-carbazol-3-yl]-ethanone, O-ethoxycarbonyl-α-oxyamino-1-phenylpropane-1-one, 1,2-octanedione, 2-dimethylamino-2-(4-methylbenzyl)-1-(4-morpholinyl-4-yl-phenyl)-butane-1-one, 1-(4-phenylsulfonylphenyl)-butane-1,2-dione-2-oxime-O-benzoic acid, 1-(4-phenylsulfonylphenyl)-octane-1,2-dione-2-oxime-O-benzoic acid, 1-(4-phenylsulfonylphenyl)-octane-1-one oxime-O-acetate, 1-(4-phenylsulfonylphenyl)-butane-1-one oxime-O-acetate, 2-(O-benzoyloxime)-1-[4-(phenylthio)-p-methylphenyl]-1,Oxime ester compounds such as 2-octanedione, 2-(O-benzoyloxime)-1-[4-(phenylthio)phenyl]-1,2-phenyldione, 2-(O-acetyloxime)-1-[4-(phenylthio)phenyl]-1,2-octanedione, 2-(O-acetyloxime)-1-[4-(phenylthio)phenyl]-1,2-phenyldione, 2-(O-acetyloxime)-1-[4-(phenylthio)phenyl]-1,2-methyldione, O-(acetyl)-N-(1-phenyl-2-keto-2-(4'-methoxy-naphthyl)ethylidene)hydroxylamine, and di(2,4,6-trimethylbenzoyl) Phosphine compounds such as phenylphosphine oxide, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, 2,2'-bis(o-chlorophenyl)-4,5,4',5'-tetraphenyl-1,2'-biimidazole, 2,2'-bis(o-methoxyphenyl)-4,4',5,5'-tetraphenylbiimidazole, 2,2'-bis(o-methoxyphenyl)-4,4',5,5'-tetra(p-methylphenyl)biimidazole, quinone compounds such as 9,10-phenanthrenequinone, camphorquinone, ethylanthraquinone, borate compounds, carbazole compounds, titanocene compounds, etc., and these can be used alone or in combination.

[0045] The content of the free radical photoinitiator is preferably 0.1 to 20 parts by weight relative to 100 parts by weight of the acrylic copolymer. When the content of the free radical photoinitiator is less than 0.1 parts by weight, the film retention rate is deteriorated due to low sensitivity, and when it exceeds 20 parts by weight, there are problems of reduced developability and reduced resolution.

[0046] The ionic photoinitiator may include a cationic photoinitiator and an anionic photoinitiator. The cationic photoinitiator may be a sulfonium salt system, an iodonium salt system, a phosphonium salt system, a diazonium salt system, a pyridinium salt system, a benzothiazolium salt system, an oxidized sulfur salt system, a ferrocene compound, and in addition, nitrobenzene sulfonic acid, an alkyl or aryl-N-sulfonyloxy imide, a halogenated alkyl sulfonate, a sulfonic acid oxime ester, etc., but is not limited thereto.

[0047] As an example, the cationic photoinitiator can be selected from tetrabutylammonium tetrafluoroborate, tetrabutylammonium hexafluorophosphate, tetrabutylammonium hydrogen sulfate, tetraethylammonium tetrafluoroborate, tetraethylammonium, p-toluenesulfonic acid, N,N-dimethyl-N-benzylaniline antimony hexafluoride, N,N-dimethyl-N-benzylaniline boron tetrafluoride, N,N-dimethyl-N-benzylpyridinium antimony hexafluoride, N,N-dimethyl-N-benzyl trifluoromethanesulfonic acid, N,N-dimethyl-N-(4-methoxybenzyl)pyridinium antimony hexafluoride, N,N-dimethyl-N-(4-methoxybenzyl)toluidinium antimony hexafluoride, ethyltriphenylphosphine antimony hexafluoride, tetrabutylphosphine antimony hexafluoride, triphenylsulfonium boron tetrafluoride, triphenylsulfonium antimony hexafluoride, triphenylsulfonium arsenic hexafluoride, tri(4-methoxyphenyl)sulfonium Arsenic hexafluoride, diphenyl(4-phenylthiophenyl)sulfonium arsenic hexafluoride, diphenyliodonium arsenic hexafluoride, di-4-chlorophenyliodonium arsenic hexafluoride, di-4-bromophenyliodonium arsenic hexafluoride, phenyl(4-methoxyphenyl)iodonium arsenic hexafluoride, diphenyliodonium phosphorus hexafluoride, di-4-chlorophenyliodonium phosphorus hexafluoride, di-4-bromophenyliodonium phosphorus hexafluoride, phenyl(4-methoxyphenyl)iodonium arsenic hexafluoride, At least one of the group consisting of, but not limited to, 4-(2-methylpropylphenyl))iodonium phosphorus hexafluoride, 4-(4-(2-methylpropylphenyl))iodonium phosphorus hexafluoride, di-4-tetraphenyliodonium phosphorus hexafluoride, diphenyliodonium phosphorus hexafluoride, di-4-tetraphenyliodonium antimony hexafluoride, diphenyliodonium antimony hexafluoride, and 4-methylphenyl(4-(2-methylpropylphenyl))iodonium arsenic tetrafluoride.

[0048] The anionic photoinitiator may be one or more selected from the group consisting of benzoin carbamate, dimethylbenzyloxycarbamide, o-acyloxime, o-nitrobenzoin carbamate, formanilide derivatives, and α-aminoacetophenone, but is not limited thereto.

[0049] The content of the ionic photoinitiator may be 0.1 to 10 parts by weight relative to 100 parts by weight of the acrylic copolymer. When the content of the ionic photoinitiator is less than 0.1 parts by weight, chemical resistance may be deteriorated due to low degree of curing, and when the content exceeds 10 parts by weight, residue may be generated due to excessive degree of curing and resolution may be reduced.

[0050] The multifunctional acrylate oligomer contained in the photosensitive resin composition according to the present embodiment has 2 to 20 functional groups. As an example, aliphatic urethane acrylate oligomer, aromatic urethane acrylate oligomer, epoxy acrylate oligomer, epoxy methacrylate oligomer, polyester acrylate oligomer, silicon acrylate oligomer, melamine acrylate oligomer, dendritic acrylate oligomer, etc. can be used, and these can also be used alone or in combination of two or more.

[0051] The content of the multifunctional acrylate oligomer is preferably 1 to 50 parts by weight relative to 100 parts by weight of the acrylic copolymer. When the content of the multifunctional acrylate oligomer is less than 1 part by weight, the film retention rate may be deteriorated due to low sensitivity, and when the content exceeds 50 parts by weight, the developability may be reduced and the resolution may be reduced.

[0052] Furthermore, the multifunctional monomer having an ethylenically unsaturated bond contained in the photosensitive resin composition according to one embodiment of the present invention may use 1,4-butanediol diacrylate, 1,3-butanediol diacrylate, ethylene glycol diacrylate, trimethylolpropane diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, triethylene glycol diacrylate, polyethylene glycol diacrylate, dipentaerythritol hexaacrylate, dipentaerythritol triacrylate, dipentaerythritol diacrylate, sorbitol triacrylate, bisphenol A diacrylate derivatives, dipentaerythritol polyacrylate, and their methacrylates, etc., and these may be used alone or in combination of two or more.

[0053] The content of the multifunctional monomer having the ethylenically unsaturated bond may be 1 to 50 parts by weight relative to 100 parts by weight of the acrylic copolymer. When the content is less than 1 part by weight, the film retention rate may be poor due to low sensitivity, and when the content exceeds 50 parts by weight, the developability may be reduced and the resolution may be reduced.

[0054] The solvent used in the photosensitive resin composition according to an embodiment of the present invention is not limited, for example, its boiling point may be less than 150° C. When a solvent with a boiling point less than 150° C. is used, residual solvent in a low temperature process can be minimized and chemical resistance can be ensured.

[0055] For example, the solvent can be selected from the group consisting of esters such as methyl 2-hydroxyisobutyrate, ethylene glycol methyl ether acetate, 2-methoxy-1-methylethyl ester, propylene acetate, ethyl propionate, and ethyl pyruvate, ethers such as 1-methoxy-2-propanol, dibutyl ether, ethylene glycol monoethyl ether, ethylene glycol dimethyl ether, propylene glycol dimethyl ether, and tetrahydrofuran, and alcohols such as methanol, ethanol, and isopropanol, and one or more can be used in consideration of solubility, reactivity with each component, ease of film formation, etc.

[0056] Preferably, the solvent is included in the overall photosensitive resin composition so that the solid content is 10 to 50% by weight. The composition having the solid content in the above range can be used after filtering with a 0.1 to 0.2 μm microporous filter or the like. In addition, for example, in the photosensitive resin composition, the content of the solvent can be in the range of 15 to 40% by weight.

[0057] When the solid content of the photosensitive resin composition is less than 10 wt %, there are problems that the coating thickness becomes thinner and the coating flatness decreases. When it exceeds 50 wt %, the coating thickness becomes thicker and the coating equipment may be overloaded during coating, and the residual solvent may increase.

[0058] Furthermore, the photosensitive composition according to the present embodiment may further include a melamine crosslinking agent, which improves the heat resistance, chemical resistance and adhesion of the photosensitive composition.

[0059] As the melamine crosslinking agent, a condensation product of urea and formaldehyde, a condensation product of melamine and formaldehyde, or methylol urea alkyl ethers or methylol melamine alkyl ethers obtained from alcohols can be used.

[0060] Specifically, as the condensation product of urea and formaldehyde, monomethylol urea, dimethylol urea, etc. can be used. As the condensation product of melamine and formaldehyde, hexamethylol melamine can be used, and in addition, partial condensation products of melamine and formaldehyde can be used.

[0061] Furthermore, the methylol urea alkyl ethers are obtained by reacting part or all of the methylol groups with alcohols in a condensation product of urea and formaldehyde, and monomethyl urea methyl ether, dimethyl urea methyl ether, etc. can be used as specific examples. The methylol melamine alkyl ethers are obtained by reacting part or all of the methylol groups with alcohols in a condensation product of melamine and formaldehyde, and hexamethylol melamine hexamethyl ether, hexamethylol melamine hexabutyl ether, etc. can be used as specific examples. Furthermore. Compounds having a structure in which the hydrogen atoms of the amino group of melamine are substituted with methylol and methoxymethyl, compounds having a structure in which the hydrogen atoms of the amino group of melamine are substituted with butoxymethyl and methoxymethyl, etc. can also be used, and methylol melamine alkyl ethers are particularly preferably used.

[0062] The content of the melamine cross-linking agent may be 0.1 to 20 parts by weight relative to 100 parts by weight of the acrylic copolymer.

[0063] Furthermore, the photosensitive composition according to the present embodiment may further include a silane coupling agent. The silane coupling agent improves the adhesion between the photosensitive resin composition and the lower substrate. The silane coupling agent may be (3-glycidyloxypropyl)trimethoxysilane, (3-glycidyloxypropyl)triethoxysilane, (3-glycidyloxypropyl)methyldimethoxysilane, (3-glycidyloxypropyl)methyldiethoxysilane, (3-glycidyloxypropyl)dimethylethoxysilane, 3,4-epoxybutyltrimethoxysilane, 3,4-epoxybutyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrieth ...methoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysil 4-epoxycyclohexyl)ethyltriethoxysilane, aminopropyltrimethoxysilane, aminopropyltriethoxysilane, 3-triethoxysilyl-N-(1,3-dimethyl-butylene)propylamine, N-2(aminoethyl)3-aminopropyltrimethoxysilane, N-2(aminoethyl)3-aminopropyltriethoxysilane, N-2(aminoethyl)3-aminopropylmethyldimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane or (3-isocyanatopropyl)triethoxysilane can be used alone or in combination of two or more.

[0064] The silane coupling agent may be included in an amount of 0.1 to 20 parts by weight based on 100 parts by weight of the acrylic copolymer.

[0065] Furthermore, the photosensitive resin composition according to an embodiment of the present invention may further include a surfactant. Such a surfactant may improve the coating and developing properties of the photosensitive resin composition. Such surfactants include silicon-based and fluorine-based surfactants. The surfactant may be included in an amount of 0.0001 to 2 parts by weight relative to 100 parts by weight of the solid content in the photosensitive resin composition.

[0066] Hereinafter, a method for forming a pattern using a photosensitive resin composition according to an embodiment of the present invention is described. The method for forming a pattern using a photosensitive resin composition according to an embodiment of the present invention comprises the following steps: coating a photosensitive resin composition on a substrate; heating the photosensitive resin composition once at a temperature of 75° C. to 85° C.; exposing and developing the photosensitive resin composition; and heating the developed photosensitive resin composition twice at a temperature of 80° C. to 90° C. The photosensitive resin composition used at this time is the same as the photosensitive resin composition described above. Repeated descriptions of the same components are omitted.

[0067] Figures 1 to 4 FIG. 4 is a process flow chart showing a pattern forming method according to an embodiment of the present invention.

[0068] Reference Figure 1, a photosensitive resin composition 400 is coated on the substrate 110 to form a photosensitive resin composition coating layer 400. At this time, the coating can be performed by spray coating, roller coating, spin coating, etc.

[0069] At this time, the photosensitive resin composition includes 0.1 to 20 parts by weight of a free radical photoinitiator, 0.1 to 10 parts by weight of an ionic photoinitiator, 1 to 50 parts by weight of a multifunctional acrylate oligomer, 1 to 50 parts by weight of a multifunctional monomer having an ethylenically unsaturated bond, and a solvent, relative to 100 parts by weight of the acrylic copolymer. This photosensitive resin composition includes both a free radical photoinitiator and an ionic photoinitiator, so that it can be cured at a low temperature below 90°C, and when cured at a low temperature below 90°C, it also exhibits excellent adhesion and chemical resistance. This photosensitive resin composition is a negative photosensitive resin composition in which the exposed part is partially cured and remains.

[0070] Next, refer to Figure 2 The coated photosensitive resin composition 400 is heated once at a temperature of 75°C to 85°C. This is a pre-baking process, and the gas contained in the coated photosensitive resin composition 400 is removed by the above process. The first heating can be performed for about 1 minute to 5 minutes. At this time, the photosensitive resin composition of the present invention uses a solvent with a boiling point of less than 150°C, so the gas contained in the solvent can be better removed.

[0071] Next, refer to Figure 3 , the coated photosensitive resin composition is exposed and developed to form a photosensitive resin composition layer 410. The photosensitive resin composition according to an embodiment of the present invention is a negative photosensitive resin composition, and the portion corresponding to the opening of the mask 700, that is, the exposed portion, is cured and remains, while the unexposed portion is removed. At this time, visible light, ultraviolet light, far ultraviolet light, electron beam or X-ray can be used for exposure. A developer is used in development, and the unexposed portion is removed.

[0072] The developer preferably uses an alkaline aqueous solution, specifically, inorganic bases such as sodium hydroxide, potassium hydroxide, sodium carbonate, etc.; primary amines such as n-propylamine, etc.; secondary amines such as diethylamine, n-propylamine, etc.; tertiary amines such as trimethylamine, methyldiethylamine, dimethylethylamine, triethylamine, etc.; alcohol amines such as dimethylethanolamine, methyldiethanolamine, triethanolamine, etc.; or aqueous solutions of quaternary ammonium salts such as tetramethylammonium hydroxide and tetraethylammonium hydroxide, etc. In this case, the developer is used by dissolving the alkaline compound at a concentration of 0.1 to 10% by weight, and an appropriate amount of a water-soluble organic solvent such as methanol, ethanol, etc. and a surfactant can be added.

[0073] Next, refer to Figure 4, the photosensitive resin composition layer 410 is reheated at a temperature of 80° C. to 90° C. The reheating is a process for curing the photosensitive resin composition layer 410. The reheating can be performed for about 30 minutes to 240 minutes. The photosensitive resin composition according to one embodiment of the present invention is cured at a temperature below 90° C., so even if a light-emitting layer is arranged below the photosensitive resin composition, an insulating film can be manufactured without damaging the light-emitting layer.

[0074] That is, the photosensitive resin composition of the present invention can be used as a passivation insulating film, a gate insulating film, a planarizing film, a columnar spacer, an excess coating or a color photoresist contained in a display element such as a TFT-LCD, a touch screen panel (TouchScreen Panel; TSP) or an OLED. In this case, the photosensitive resin composition is cured by a low temperature process, so it can be manufactured by a single process on a structure including a light-emitting layer, etc., so the process can be simplified.

[0075] Furthermore, the structure of the manufactured display device can be simplified. For example, by utilizing the pattern forming method of the photosensitive resin composition according to the present embodiment, a display device having a structure in which a touch panel is built into an organic light-emitting element can be manufactured. That is, a touch sensing electrode is directly formed on the thin film encapsulation layer on the organic light-emitting element, and the photosensitive resin composition according to the present embodiment can be utilized as an insulating film located between the touch sensing electrodes. For the above structure, in the process of manufacturing the insulating film, if the temperature exceeds 100°C, the light-emitting layer of the organic light-emitting element is damaged, so it is not preferred. However, in the photosensitive resin composition according to the present embodiment and the pattern forming method using the same, the photosensitive resin composition is cured at a temperature below 90°C, so an insulating film or the like can be manufactured without damaging the lower light-emitting layer.

[0076] Next, the effects of the photosensitive resin composition and the pattern forming method using the composition according to an embodiment of the present invention are described below through specific experimental examples.

[0077] Synthesis Example 1: (Production of acrylic acid-based copolymer)

[0078] 400 parts by weight of tetrahydrofuran, 30 parts by weight of methacrylic acid, 30 parts by weight of styrene and 40 parts by weight of a methyl methacrylate mixed solution were placed in a flask equipped with a cooler and a stirrer. The liquid composition was fully mixed in a mixing container at 600 rpm, and then 15 parts by weight of 2,2'-azobis(2,4-dimethylvaleronitrile) was added, and the polymerization mixed solution was slowly heated to 55°C, and then maintained at this temperature for 24 hours, and then cooled to room temperature, and then 500 ppm of hydroxybenzophenone was added as a polymerization inhibitor to obtain a polymer solution with a solid content of 30% by weight.

[0079] In order to remove the unreacted monomers of the polymer solution, 100 parts by weight of the polymer solution was precipitated in 1000 parts by weight of n-hexane. After the precipitation, the solvent (Poor solvent) in which the unreacted products were dissolved was removed by a filtration process using a mesh. Then, in order to remove the solvent containing the unreacted monomers remaining after the filtration process, the solvent containing the unreacted monomers was completely removed by vacuum drying at 30 degrees or less, thereby producing an acrylic copolymer.

[0080] The weight average molecular weight of the acrylic copolymer was 6,000. Here, the weight average molecular weight is a polystyrene-equivalent average molecular weight measured by GPC.

[0081] Example 1: Preparation of negative photosensitive resin composition

[0082] 100 parts by weight of the acrylic copolymer solution prepared in Synthesis Example 1, 10 parts by weight of 2-(O-benzoyloxime)-1-[4-(phenylthio)phenyl]-1,2-octanedione as a free radical photoinitiator, 10 parts by weight of phenyl(4-methoxyphenyl)iodonium phosphorus hexafluoride as an ionic photoinitiator, 10 parts by weight of a 10-functional urethane acrylate oligomer, 20 parts by weight of dipentaerythritol hexaacrylate as a multifunctional monomer having an ethylenically unsaturated bond, 3 parts by weight of hexamethylolmelamine hexamethoxyether as a melamine crosslinking agent, and 2 parts by weight of (3-glycidyloxypropyl)methyldiethoxysilane as a silane coupling agent were mixed. Propylene glycol monoethyl acetate was added to the mixture to dissolve it so that the solid content concentration became 20% by weight, and then filtered with a 0.2 μm microporous filter to prepare a negative photosensitive resin composition coating solution.

[0083] Example 2: Preparation of negative photosensitive resin composition

[0084] A photosensitive resin composition coating solution was prepared by the same method as in Example 1 except that ethylene glycol methyl ether acetate was used as the solvent.

[0085] Example 3: Preparation of negative photosensitive resin composition

[0086] In Example 1, a photosensitive resin composition coating solution was prepared by the same method as in Example 1 except that N,N-dimethyl-N-benzyltrifluoromethanesulfonic acid was used as the ionic photoinitiator.

[0087] Example 4: Preparation of negative photosensitive resin composition

[0088] A photosensitive resin composition coating solution was prepared by the same method as in Example 1 except that 4-methylphenyl(4-(2-methylpropylphenyl))iodonium phosphorus hexafluoride was used as the ionic photoinitiator.

[0089] Example 5: Preparation of negative photosensitive resin composition

[0090] A photosensitive resin composition coating solution was prepared by the same method as in Example 1 except that phenyl(4-methoxyphenyl)iodonium arsenic hexafluoride was used as the ionic photoinitiator.

[0091] Comparative Example 1: Preparation of Negative Photosensitive Resin Composition

[0092] In Example 1, a photosensitive resin composition coating solution was prepared by the same method as in Example 1 except that 0.05 parts by weight of an ionic photoinitiator was used.

[0093] Comparative Example 2: Preparation of Negative Photosensitive Resin Composition

[0094] In Example 1, a photosensitive resin composition coating solution was prepared by the same method as in Example 1 except that 25 parts by weight of the ion photoinitiator was used.

[0095] Comparative Example 3: Preparation of Negative Photosensitive Resin Composition

[0096] In the embodiment 1, the photosensitive resin composition coating solution was prepared by the same method as that of the embodiment 1 except that the ionic photoinitiator was completely removed.

[0097] Comparative Example 4: Preparation of Negative Photosensitive Resin Composition

[0098] In Comparative Example 3, a photosensitive resin composition coating solution was prepared by the same method as in Comparative Example 3 except that 2-(O-acetyloxime)-1-[4-(phenylthio)phenyl]-1,2-octanedione was used as the radical photoinitiator.

[0099] Comparative Example 5: Preparation of Negative Photosensitive Resin Composition

[0100] A photosensitive resin composition coating solution was prepared by the same method as in Example 1 except that ethyl lactate was used as the solvent.

[0101] Comparative Example 6: Preparation of Negative Photosensitive Resin Composition

[0102] A photosensitive resin composition coating solution was prepared by the same method as in Example 1 except that propylene glycol monomethyl propionate was used as the solvent.

[0103] The negative photosensitive resin composition coating solutions prepared in Examples 1 to 5 and Comparative Examples 1 to 6 were used to evaluate physical properties by the methods described in Experimental Examples 1 to 5 below, and the results are shown in [Table 1].

[0104] Experimental Example 1: Sensitivity and film retention rate measurement

[0105] In the deposition of SiN x The negative photosensitive resin composition solution prepared in Examples 1 to 5 and Comparative Examples 1 to 6 was applied to a glass substrate using a spin coater, and then pre-baked on a hot plate at 80° C. for 2 minutes to form a 2.0 μm film. The film obtained as described above was irradiated with ultraviolet light at intervals of 0.2 seconds for 1 to 5 seconds using a broadband exposure device using a predetermined pattern mask, and the intensity of the ultraviolet light at 365 nm was 10 mW / cm 2 Thereafter, the film was developed with a 2.38 wt % aqueous solution of tetramethylammonium hydroxide at 23° C. for 60 seconds, and then washed with ultrapure water for 60 seconds.

[0106] For final curing, the film was heated in an oven at 85° C. for 60 minutes to obtain a pattern film. The sensitivity was measured by SEM based on 20 μm line & space CD and exposure amount at which the film retention rate reached saturation.

[0107] Experimental Example 2: Film retention rate

[0108] When measuring the sensitivity in Experiment 1, the film retention rate at which the film retention rate reaches saturation was confirmed. If the film retention rate at this time is greater than 80%, it is indicated by ○, if it is between 80% and 75%, it is indicated by △, and if it is less than 75%, it is indicated by X.

[0109] Experimental Example 3: Residue

[0110] The residue (Scum) was inspected based on the contact hole (Contact Hole) of the pattern (Pattern) film formed when measuring the sensitivity in the above-mentioned Experimental Example 1. At this time, the case where there was no residue was indicated by ○, and the case where the residue was observed was indicated by X.

[0111] Experimental Example 4: Adhesion

[0112] When the sensitivity was measured in Experimental Example 1, a case where the pattern film formed did not peel off was indicated by ◯, and a case where the pattern film peeled off was indicated by X.

[0113] Experimental Example 5: Chemical Resistance

[0114] The pattern film formed when measuring the sensitivity in Experimental Example 1 was placed in a peeler and left there, and the thickness change was measured. The case where the thickness change was less than 0.5 μm was indicated by ○, the case where it was 0.5 μm to 1.0 μm was indicated by △, and the case where it was greater than 1.0 μm was indicated by X.

[0115]

Table 1

[0116]

[0117] Table 1 shows that Examples 1 to 5 including an ionic photoinitiator and a low boiling point solvent according to an embodiment of the present invention are superior to Comparative Examples 3 to 6 in sensitivity, film retention rate, residue, adhesion, and chemical resistance.

[0118] Furthermore, by comparing Comparative Examples 1 and 2, in which the content of the ionic photoinitiator is not included in the range of 0.1 to 10 parts by weight, with Example 1, it can be confirmed that only when the content of the ionic photoinitiator is included in the range of 0.1 to 10 parts by weight, uniform performance can be exhibited in terms of film retention rate, residue and adhesive force. That is, the film retention rate and adhesive force of Comparative Example 1, in which the content of the ionic photoinitiator is 0.05 parts by weight, are poor, and the residue of Comparative Example 2, in which the content of the ionic photoinitiator is 25 parts by weight, is poor.

[0119] That is, as described above, the photosensitive resin composition according to one embodiment of the present invention, which contains both a free radical photoinitiator and an ion photoinitiator, has excellent sensitivity, film retention rate, residue, etc., especially in a low-temperature process below 90°C, has excellent adhesion and chemical resistance, and is therefore suitable for use in flexible displays.

[0120] The embodiments of the present invention are described in detail above, but the scope of the present invention is not limited thereto. Various modifications and improvements of the basic concept of the present invention defined in the claims by those skilled in the art also fall within the scope of the present invention.

Claims

1. A photosensitive resin composition, wherein: The acrylic copolymer comprises: 0.1 to 20 parts by weight of a free radical photoinitiator; 0.1 to 10 parts by weight of an ionic photoinitiator; 1 to 50 parts by weight of a multifunctional acrylate oligomer; 1 to 50 parts by weight of a multifunctional monomer having an ethylenically unsaturated bond; and Solvents, The multifunctional monomer having an ethylenically unsaturated bond is selected from at least one of 1,4-butanediol diacrylate, 1,3-butanediol diacrylate, ethylene glycol diacrylate, trimethylolpropane diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, triethylene glycol diacrylate, polyethylene glycol diacrylate, dipentaerythritol hexaacrylate, dipentaerythritol triacrylate, dipentaerythritol diacrylate, sorbitol triacrylate, bisphenol A diacrylate derivatives, dipentaerythritol polyacrylate, and methacrylates thereof. The photosensitive resin composition is cured at a temperature below 90° C.

2. The photosensitive resin composition according to claim 1, wherein The free radical photoinitiator is 2-(O-benzoyloxime)-1-[4-(phenylthio)phenyl]-1,2-octanedione or 2-(O-acetyloxime)-1-[4-(phenylthio)phenyl]-1,2-octanedione.

3. The photosensitive resin composition according to claim 1, wherein The ionic photoinitiator is one selected from the group consisting of phenyl(4-methoxyphenyl)iodonium phosphorus hexafluoride, N,N-dimethyl-N-benzyltrifluoromethanesulfonic acid, 4-methylphenyl(4-(2-methylpropylphenyl))iodonium phosphorus hexafluoride and phenyl(4-methoxyphenyl)iodonium arsenic hexafluoride.

4. The photosensitive resin composition according to claim 1, wherein The content ratio of the free radical photoinitiator to the ionic photoinitiator is 2:1 to 1:

2.

5. The photosensitive resin composition according to claim 1, wherein The solid content of the photosensitive resin composition is 10 wt % to 50 wt %.

6. The photosensitive resin composition according to claim 1, wherein Also included is a melamine crosslinking agent, wherein the melamine crosslinking agent is one or more selected from the group consisting of monomethylol urea, dimethylol urea, hexamethylol melamine, monomethyl urea methyl ether, dimethyl urea methyl ether, hexamethylol melamine hexamethyl ether and hexamethylol melamine hexabutyl ether.

7. The photosensitive resin composition according to claim 1, wherein The invention also includes: a silane coupling agent, wherein the silane coupling agent is selected from (3-glycidyloxypropyl)trimethoxysilane, (3-glycidyloxypropyl)triethoxysilane, (3-glycidyloxypropyl)methyldimethoxysilane, (3-glycidyloxypropyl)methyldiethoxysilane, (3-glycidyloxypropyl)dimethylethoxysilane, 3,4-epoxybutyltrimethoxysilane, 3,4-epoxybutyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane , 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane, aminopropyltrimethoxysilane, aminopropyltriethoxysilane, 3-triethoxysilyl-N-(1,3-dimethyl-butylene)propylamine, N-2(aminoethyl)3-aminopropyltrimethoxysilane, N-2(aminoethyl)3-aminopropyltriethoxysilane, N-2(aminoethyl)3-aminopropylmethyldimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane and (3-isocyanatepropyl)triethoxysilane.

8. The photosensitive resin composition according to claim 1, wherein The acrylic copolymer is formed by copolymerizing an unsaturated carboxyl compound and an unsaturated olefin compound.

9. The photosensitive resin composition according to claim 1, wherein The boiling point of the solvent is less than 150°C.

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