Alkali-soluble resin containing polymerizable unsaturated group, photosensitive resin composition containing the same as an essential component, and cured product thereof

Abstract

The present application provides a photosensitive resin composition that has high heat resistance and is capable of maintaining a rectangular cross-sectional shape and not exhibiting heat-sagging, and a cured product thereof. A polymerizable unsaturated group-containing alkali-soluble resin according to the present invention is represented by general formula (1) and has, in each molecule, a carboxy group and a polymerizable unsaturated group. (In formula (1), X1 represents a tetravalent aromatic ring-containing group, and Y1 represents a divalent aromatic ring-containing group. A portion of the hydrogen atoms in X1 and Y1 are optionally substituted with a linear or branched chain hydrocarbon group having 1-20 carbon atoms. V1 is a substituent represented by general formula (2). The value of l, as an average, is 0.2-4.0. Q1 is a hydrogen atom or a linear or branched chain hydrocarbon group having 1-20 carbon atoms.) (In formula (2), R1 represents a hydrogen atom or a methyl group. L represents a substituent represented by general formula (3). * represents a binding site with an oxygen atom (O) in formula (1).) (In formula (3), M represents a divalent or trivalent residue derived from a dicarboxylic acid, a tricarboxylic acid, or an acid monoanhydride of either, and p is 1 or 2. * represents a binding site with an oxygen atom (O) in formula (2).)

Description

[Technical Field]

[0001] The present invention relates to an alkali-soluble resin containing a polymerizable unsaturated group, a photosensitive resin composition containing the same as an essential component, and a cured product thereof. [Background technology]

[0002] In recent years, with the increasing performance and resolution of electronic devices, display components, and the like, miniaturization and high density have been required for the electronic components used therein. Furthermore, there has been a growing demand for finer processing of the insulating materials used therein, as well as for optimization of the cross-sectional shape of the processed patterns. Patterning by exposure and development is known as an effective means for fine processing of insulating materials, and photosensitive resin compositions have been used in this process. However, there has been a growing demand for various properties, such as high sensitivity, adhesion to substrates, reliability, heat resistance, and chemical resistance.

[0003] Conventional insulating materials made from photosensitive resin compositions utilize a photocuring reaction between a photoreactive alkali-soluble resin and a photopolymerization initiator. The i-line (365 nm), a line spectrum of a mercury lamp, is typically used as the exposure wavelength for photocuring. However, this i-line is absorbed by the photosensitive resin itself and colorants, resulting in a decrease in the degree of photocuring. Furthermore, the amount of absorption increases with thicker films. This results in a difference in crosslink density across the film thickness in the exposed area. As a result, even if the surface of the coating film is sufficiently photocured, the bottom surface of the coating film is less photocured, making it extremely difficult to achieve a difference in crosslink density between the exposed and unexposed areas. This makes it difficult to obtain insulating materials made from photosensitive resin compositions that can be developed with high resolution and have the desired pattern dimensional stability, development margin, pattern adhesion, and pattern edge and cross-sectional shape.

[0004] Generally, photosensitive resin compositions for such applications contain a polyfunctional photocurable monomer having a polymerizable unsaturated bond, an alkali-soluble binder resin, a photopolymerization initiator, etc., and photosensitive resin compositions disclosed as technical applications for color filter materials can be used. For example, Patent Documents 1 and 2 disclose copolymers of (meth)acrylic acid or (meth)acrylic acid esters having a carboxy group, maleic anhydride, and other polymerizable monomers as binder resins.

[0005] Furthermore, Patent Document 3 discloses that an alkali-soluble unsaturated compound having a polymerizable unsaturated group and a carboxyl group in one molecule is effective for forming negative patterns such as color filters.

[0006] On the other hand, Patent Documents 4, 5, 6 and 7 disclose liquid resins using reaction products of epoxy (meth)acrylates having a bisphenol fluorene structure and acid anhydrides.

[0007] Furthermore, Patent Documents 8, 9, and 10 disclose alkali-developable unsaturated resin compositions obtained by copolymerizing dihydroxypropyl acrylate with an acid dianhydride, or alkali-developable unsaturated resin compositions obtained by copolymerizing an acid monoanhydride and an acid dianhydride with dihydroxypropyl acrylate. In these cases, the copolymerization of the acid dianhydride with dihydroxypropyl acrylate proceeds to produce an oligomer.

[0008] Furthermore, Patent Document 11 discloses the multifunctionalization of an alkali-soluble resin composition to increase the molecular weight of a carboxyl group-containing copolymer. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Application Publication No. 61-213213 [Patent Document 2] Japanese Patent Application Publication No. 1-152449 [Patent Document 3] Japanese Patent Application Publication No. 4-340965 [Patent Document 4] Japanese Patent Application Publication No. 4-345673 [Patent Document 5] Japanese Patent Application Publication No. 4-345608 [Patent Document 6] Japanese Patent Application Publication No. 4-355450 [Patent Document 7] Japanese Patent Application Publication No. 4-363311 [Patent Document 8] Japanese Patent Application Publication No. 5-339356 [Patent Document 9] Japanese Patent Application Publication No. 7-3122 [Patent Document 10] International Publication No. 94 / 00801 [Patent Document 11] Japanese Patent Application Publication No. 9-325494 Summary of the Invention [Problem to be solved by the invention]

[0010] However, the copolymers disclosed in Patent Documents 1 and 2 are random copolymers, and therefore a distribution of alkali dissolution rates occurs in the light-irradiated and non-irradiated areas, narrowing the margin during development, making it difficult to obtain sharp-angled pattern shapes or fine patterns.

[0011] Furthermore, the alkali-soluble unsaturated compound described in Patent Document 3 is insolubilized by light irradiation, and is therefore expected to have higher sensitivity than the combination of the binder resin and polyfunctional polymerizable monomer described above. Examples of compounds described in Patent Document 3 include compounds in which acrylic acid and acid anhydride, which are polymerizable unsaturated bond groups, are added to the hydroxyl groups of a phenol oligomer. Even with the compound described in Patent Document 3, a wide distribution occurs in the molecular weight of each molecule and the amount of carboxyl groups, resulting in a wide distribution in the alkali dissolution rate of the alkali-soluble resin, making it difficult to form fine negative patterns.

[0012] Furthermore, examples of resins described in Patent Documents 4, 5, 6, and 7 include reaction products of epoxy (meth)acrylate and acid monoanhydride. Because this reaction product has a small molecular weight, it is difficult to increase the difference in alkali solubility between exposed and unexposed areas, making it impossible to form fine patterns.

[0013] Furthermore, the copolymers described in Patent Documents 8, 9, 10, and 11 have a small number of polymerizable unsaturated bonds, and therefore do not provide sufficient crosslinking density. Therefore, there is room for improvement in the copolymer structure, such as by increasing the proportion of polymerizable unsaturated bonds in one molecule.

[0014] Furthermore, photosensitive resin compositions are also desired to have high heat resistance, i.e., to have little deformation in the cross-sectional shape of the pattern even after a thermal curing step following exposure and development, when used as resists for various color filters or insulating films in semiconductor devices, etc. In particular, when forming fine line patterns of 10 μm or less or via patterns of 50 μm or less in diameter, it is necessary to minimize changes in pattern dimensions due to heat sagging and maintain the rectangular shape of the pattern.

[0015] Alternatively, photosensitive resin compositions for producing cured films used in insulating films and the like are required to have both high adhesion to substrates and reduced residue, and also be capable of forming nearly rectangular patterns.

[0016] An object of the present invention is to provide a photosensitive resin composition and a cured product thereof that have high heat resistance and can maintain a rectangular cross-sectional shape without sagging due to heat, or that can form a pattern shape close to a rectangle while achieving both high adhesion to a substrate and suppressing residue. Another object of the present invention is to provide a technology that is effective especially when strict requirements are placed on the heat resistance of the cured product. [Means for solving the problem]

[0017] As a result of intensive research to solve the above-mentioned problems, the present inventors have found that a photosensitive resin composition using an alkali-soluble resin containing a polymerizable unsaturated group is suitable for forming a cured film that requires photopatterning and has excellent heat resistance. The photosensitive resin composition is prepared by reacting a resin in which an aromatic compound having two hydroxy groups (e.g., a compound having two phenolic hydroxyl groups directly bonded to an aromatic ring, such as biphenol or naphthalenediol) is bonded via a divalent aromatic ring-containing group (a resin similar to a so-called phenol aralkyl resin) with a carboxyl group-containing (meth)acrylate, and then reacting the resulting polyhydric alcohol compound having a polymerizable unsaturated group with a dicarboxylic acid, tricarboxylic acid, or an acid monoanhydride thereof.

[0018] The alkali-soluble resin of the present invention is an alkali-soluble resin having a carboxy group and a polymerizable unsaturated group in one molecule, represented by the following general formula (1).

[0019] [ka]

[0020] In formula (1), X1 represents a tetravalent aromatic ring-containing group, and Y1 represents a divalent aromatic ring-containing group. Some of the hydrogen atoms of X1 and Y1 may be substituted with a linear or branched chain hydrocarbon group having 1 to 20 carbon atoms. V1 is a substituent represented by the following general formula (2). The average value of l is 0.2 to 4.0. Q1 is a hydrogen atom or a linear or branched chain hydrocarbon group having 1 to 20 carbon atoms.

[0021] [ka]

[0022] In formula (2), R1 represents a hydrogen atom or a methyl group. L represents a substituent represented by the following general formula (3). * represents the bonding site with the oxygen atom (O) in formula (1).

[0023] [ka]

[0024] In formula (3), M represents a divalent or trivalent residue derived from a dicarboxylic acid, tricarboxylic acid, or an acid monoanhydride thereof, and p is 1 or 2. * represents the bonding site with the oxygen atom (O) in formula (2).

[0025] The photosensitive resin composition of the present invention contains, as essential components, (i) the alkali-soluble resin, (ii) a photopolymerizable monomer having at least one polymerizable unsaturated group, and (iii) a photopolymerization initiator.

[0026] The cured product of the present invention is obtained by curing the above-mentioned photosensitive resin composition. [Effects of the Invention]

[0027] According to the present invention, by including an alkali-soluble resin having a carboxyl group and a polymerizable unsaturated group in one molecule represented by general formula (1), it is possible to provide a photosensitive resin composition and a cured product thereof that have high heat resistance and can maintain a rectangular cross-sectional shape without being sagged by heat. Alternatively, it is possible to achieve both high adhesion to the substrate and reduced residue, and form a pattern shape that is close to rectangular. Furthermore, it is possible to provide a technology that is effective when strict requirements for the heat resistance of the cured product are required. DETAILED DESCRIPTION OF THE INVENTION

[0028] Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the following embodiments. In the present invention, when the first decimal place of the content of each component is 0, the notation after the decimal point may be omitted.

[0029] The photosensitive resin composition according to one embodiment of the present invention contains, as essential components, (i) an alkali-soluble resin represented by general formula (1), (ii) a photopolymerizable monomer having at least one polymerizable unsaturated group, and (iii) a photopolymerization initiator. Each component will be described below.

[0030] [Alkali-soluble resin] The alkali-soluble resin represented by general formula (1) will be described below.

[0031] The alkali-soluble resin represented by the following general formula (1) has a carboxyl group and a polymerizable unsaturated group in one molecule. The alkali-soluble resin can be obtained by reacting a resin in which an aromatic compound having two hydroxyl groups (e.g., a compound having two phenolic hydroxyl groups directly bonded to an aromatic ring, such as biphenol or naphthalenediol) is bonded via a divalent aromatic ring-containing group (a resin similar to a so-called phenol aralkyl resin) with a cyclic ether compound such as epichlorohydrin to obtain an epoxy compound having two or more glycidyl ether groups, and a carboxylic acid compound having an unsaturated group such as (meth)acrylic acid, and then reacting the resulting polyhydric alcohol compound having a polymerizable unsaturated group with a dicarboxylic acid, tricarboxylic acid, or an acid monoanhydride thereof.

[0032] [ka]

[0033] In formula (1), X1 represents a tetravalent aromatic ring-containing group, and Y1 represents a divalent aromatic ring-containing group. Some of the hydrogen atoms of X1 and Y1 may be substituted with a linear or branched chain hydrocarbon group having 1 to 20 carbon atoms. V1 is a substituent represented by the following general formula (2). 1 represents a number from 0 to 20, and the average value of 1 is preferably 0.2 to 4.0. Q1 is a hydrogen atom or a linear or branched chain hydrocarbon group having 1 to 20 carbon atoms.

[0034] [ka]

[0035] In formula (2), R1 represents a hydrogen atom or a methyl group. L represents a substituent represented by the following general formula (3). * represents the bonding site with the oxygen atom (O) in formula (1).

[0036] [ka]

[0037] In formula (3), M represents a divalent or trivalent residue derived from a dicarboxylic acid, tricarboxylic acid, or an acid monoanhydride thereof, and p is 1 or 2. * represents the bonding site with the oxygen atom (O) in formula (2).

[0038] For example, the alkali-soluble resin represented by general formula (1) can be an alkali-soluble resin derived from a biphenol aralkyl resin represented by the following general formula (4): X2, Y2, V2, and Q2 in formula (4) correspond to X1, Y1, V1, and Q1 in formula (1), respectively.

[0039] [ka]

[0040] In formula (4), X2 is a tetravalent substituent represented by the following general formula (5) derived from a biphenol compound, and Y2 is a divalent substituent represented by the following general formula (6). In the following general formulas (5) and (6), some of the hydrogen atoms may be substituted with a linear or branched hydrocarbon group having 1 to 20 carbon atoms. V2 is a substituent represented by general formula (2). m represents a number from 0 to 20, and the average value of m is preferably 0.2 to 4.0. Q2 is a hydrogen atom or a linear or branched hydrocarbon group having 1 to 20 carbon atoms.

[0041] In the above general formula (4), when X2 has a structure in which it is bonded to two Y2, the two bonds may be on only one of the benzene rings, as represented by the following general formula (5), or both benzene rings may have one bond each bonded to Y2. Note that in one embodiment of the present invention, a form in which two bonds are bonded to one benzene ring is representatively described.

[0042] [ka]

[0043] In formula (5), * indicates the bonding site to the oxygen atom (O), Y2, or Q2 in formula (4). Preferably, the upper and lower bonding sites (bonding sites at positions 4 and 4') in formula (5) are bonding sites to the oxygen atom (O) in formula (4), and the left and right bonding sites (other bonding sites) are bonding sites to Y2 or Q2 in formula (4), but this is not limitative.

[0044] [ka]

[0045] In formula (6), * indicates the bonding site with X2 in formula (4).

[0046] [ka]

[0047] In formula (2), R1 represents a hydrogen atom or a methyl group. L represents a substituent represented by the following general formula (3). * represents the bonding site with the oxygen atom (O) in formula (4).

[0048] [ka]

[0049] In formula (3), M represents a divalent or trivalent residue derived from a dicarboxylic acid, tricarboxylic acid, or an acid monoanhydride thereof, and p is 1 or 2. * represents the bonding site with the oxygen atom (O) in formula (2).

[0050] The alkali-soluble resin represented by general formula (1) according to one embodiment of the present invention has both a polymerizable unsaturated group and a carboxyl group, and therefore a photosensitive resin composition containing the alkali-soluble resin has excellent photocurability, good developability, and patterning properties. This is an effective technique, particularly when heat resistance is required when the photosensitive resin composition is cured.

[0051] [Method for producing photosensitive resin composition] (Method for producing alkali-soluble wood species) First, the method for producing the alkali-soluble resin represented by general formula (1) will be described in detail, taking the alkali-soluble resin represented by general formula (4) as an example.

[0052] The alkali-soluble resin represented by general formula (4) is an alkali-soluble resin having a polymerizable double bond and a carboxy group in one molecule, in which X2 is a tetravalent substituent represented by general formula (5) derived from a biphenol compound, Y2 is a divalent substituent represented by general formula (6), Q2 is a hydrogen atom, and V2 is a substituent represented by general formula (2) (hereinafter referred to as a biphenol aralkyl alkali-soluble resin).

[0053] The alkali-soluble resin represented by general formula (4) can be obtained by reacting a biphenol aralkyl resin, in which biphenol compounds are bonded via an aromatic ring-containing group, with a cyclic ether compound such as epichlorohydrin to obtain an epoxy compound, which is then reacted with a carboxylic acid compound containing an unsaturated group such as (meth)acrylic acid, and further reacting the resulting polyhydric alcohol compound having a polymerizable unsaturated group with a dicarboxylic acid, tricarboxylic acid, or an acid monoanhydride thereof.

[0054] Specifically, the alkali-soluble resin represented by general formula (4) can be obtained by adding a polycarboxylic acid or its anhydride to a polyhydric alcohol compound containing a polymerizable unsaturated group, which is obtained by reacting an epoxy compound having a biphenyl skeleton represented by general formula (8) below, which has two or more glycidyl ether groups in which the hydrogen atoms of the phenolic hydroxyl groups of a biphenol aralkyl resin represented by general formula (7) below are substituted with glycidyl groups. The resulting compound is then reacted with (meth)acrylic acid. The method for producing this epoxy compound having a biphenyl skeleton can be, for example, as described in International Publication No. 2011 / 74517. When producing the resin represented by general formula (8) below, it is usually obtained as a mixture of molecules with different values ​​of n.

[0055] [ka]

[0056] In formula (7), n represents a number from 0 to 20, and the average value of n is preferably 0.2 to 4.0.

[0057] [ka]

[0058] In formula (8), o represents a number of 0 to 20, and the average value of o is preferably 0.2 to 4.0. W represents a glycidyl group.

[0059] The polymerization method for the biphenol aralkyl resin can refer to the general production methods for phenol resins and phenol aralkyl resins.

[0060] Specifically, the epoxy compound represented by the general formula (8) can be obtained by reacting the biphenol aralkyl resin represented by the general formula (7) with epichlorohydrin. The method for producing the polyhydric hydroxy resin, which is the raw material for the epoxy resin, will be explained first.

[0061] In the first step, a polyhydric hydroxy resin can be obtained by condensing a biphenol with a crosslinking agent in the absence of a catalyst or in the presence of an acidic catalyst.

[0062] Examples of the biphenols include 4,4'-dihydroxybiphenyl.

[0063] Examples of the crosslinking agent include 4,4'-bis(hydroxymethyl)biphenyl, 4,4'-bis(chloromethyl)biphenyl, 4,4'-bis(bromomethyl)biphenyl, 4,4'-bis(methoxymethyl)biphenyl, 4,4'-bis(ethoxymethyl)biphenyl, etc. Among the crosslinking agents, 4,4'-bis(chloromethyl)biphenyl, 4,4'-bis(hydroxymethyl)biphenyl, and 4,4'-bis(methoxymethyl)biphenyl are preferred.

[0064] The acidic catalyst can be appropriately selected from well-known inorganic acids and organic acids, and examples of the acidic catalyst include inorganic acids such as hydrochloric acid and sulfuric acid, organic acids such as formic acid, oxalic acid and p-toluenesulfonic acid, Lewis acids such as aluminum chloride, and solid acids such as activated clay and zeolite.

[0065] In the second step, the hydrogen atom of the phenolic hydroxyl group of the biphenol aralkyl resin represented by general formula (7) is substituted with a glycidyl group to obtain an epoxy compound having a biphenyl skeleton represented by general formula (8) and two or more glycidyl ether groups. This can be produced in the same manner as in a typical epoxidation reaction of a hydroxyl group. For example, the biphenol aralkyl resin can be dissolved in excess epichlorohydrin and then reacted in the presence of an alkali metal hydroxide such as sodium hydroxide at 20 to 150°C for 1 to 10 hours.

[0066] Next, known methods can be used to react such epoxy compounds with (meth)acrylic acid. For example, 1 mole of (meth)acrylic acid is used per mole of epoxy groups. To ensure that all epoxy groups are reacted with (meth)acrylic acid, it is preferable to add (meth)acrylic acid in a slight excess over the equimolar ratio of epoxy groups to carboxy groups. It is also possible to use a resin in which some or all of the (meth)acrylic acid has been replaced with a carboxyl group-containing (meth)acrylate. A carboxyl group-containing (meth)acrylate is a compound having one carboxyl group and one or more (meth)acrylate groups in the molecule. Examples of carboxyl group-containing (meth)acrylates include 2-acryloyloxyethyl phthalate, 2-acryloyloxyethyl hexahydrophthalate, 2-acryloyloxyethyl succinate, 2-acryloyloxyhexanoic acid, and 2-methacryloyloxyhexanoic acid.

[0067] The reaction product obtained by the above reaction is an epoxy (meth)acrylate represented by the following general formula (9).

[0068] [ka]

[0069] In formula (9), q represents a number of 0 to 20, and the average value of q is preferably 0.2 to 4.0. W1 is a substituent having a polymerizable unsaturated group in the molecule, represented by the following general formula (10).

[0070] [ka]

[0071] In formula (10), R2 represents a hydrogen atom or a methyl group. * represents the bonding site with the oxygen atom (O) in formula (9).

[0072] The solvent, catalyst, and other reaction conditions used in this reaction are not particularly limited. For example, it is preferable that the solvent does not have a hydroxyl group and has a boiling point higher than the reaction temperature. Examples of such solvents include cellosolve-based solvents such as ethyl cellosolve acetate and butyl cellosolve acetate; high-boiling ether or ester-based solvents such as diglyme, ethyl carbitol acetate, butyl carbitol acetate, and propylene glycol monomethyl ether acetate; and ketone-based solvents such as cyclohexanone and diisobutyl ketone. Examples of catalysts include known catalysts such as ammonium salts such as tetraethylammonium bromide and triethylbenzylammonium chloride; and phosphines such as triphenylphosphine and tris(2,6-dimethoxyphenyl)phosphine.

[0073] The alkali-soluble resin represented by general formula (4) can be obtained by reacting the hydroxyl group of the compound represented by general formula (9) with a dicarboxylic acid, tricarboxylic acid, or an acid monoanhydride thereof.

[0074] Examples of the dicarboxylic acid or tricarboxylic acid or their acid monoanhydrides include saturated chain hydrocarbon dicarboxylic acid or tricarboxylic acid, saturated cyclic hydrocarbon dicarboxylic acid or tricarboxylic acid, unsaturated dicarboxylic acid or tricarboxylic acid, aromatic hydrocarbon dicarboxylic acid or tricarboxylic acid, or their acid monoanhydrides, etc. Each hydrocarbon residue (structure excluding the carboxy group) of these acid monoanhydrides may be substituted with a substituent such as an alkyl group, a cycloalkyl group, or an aromatic group.

[0075] Examples of acid monoanhydrides of saturated chain hydrocarbon dicarboxylic or tricarboxylic acids include acid monoanhydrides of succinic acid, acetylsuccinic acid, adipic acid, azelaic acid, citramalic acid, malonic acid, glutaric acid, citric acid, tartaric acid, oxoglutaric acid, pimelic acid, sebacic acid, suberic acid, diglycolic acid, and the like.

[0076] Examples of the acid monoanhydrides of saturated cyclic hydrocarbon dicarboxylic or tricarboxylic acids include the acid monoanhydrides of hexahydrophthalic acid, cyclobutanedicarboxylic acid, cyclopentanedicarboxylic acid, norbornanedicarboxylic acid, hexahydrotrimellitic acid, and the like.

[0077] Examples of the acid monoanhydrides of unsaturated dicarboxylic acids or tricarboxylic acids include the acid monoanhydrides of maleic acid, itaconic acid, tetrahydrophthalic acid, methylendomethylenetetrahydrophthalic acid, chlorendic acid, and the like.

[0078] Examples of the acid monoanhydrides of aromatic hydrocarbon dicarboxylic acids or tricarboxylic acids include the acid monoanhydrides of phthalic acid, trimellitic acid, and the like.

[0079] Among the above-mentioned dicarboxylic acid or tricarboxylic acid monoanhydrides, the acid monoanhydrides of succinic acid, hexahydrophthalic acid, hexahydrotrimellitic acid, maleic acid, itaconic acid, tetrahydrophthalic acid, phthalic acid, and trimellitic acid are preferred, and the acid monoanhydrides of succinic acid, hexahydrotrimellitic acid, maleic acid, itaconic acid, tetrahydrophthalic acid, phthalic acid, and trimellitic acid are more preferred. The above-mentioned dicarboxylic acid or tricarboxylic acid monoanhydrides may be used alone or in combination of two or more.

[0080] The reaction temperature when the hydroxyl group of the compound represented by general formula (10) is reacted with a dicarboxylic acid or tricarboxylic acid or an acid monoanhydride thereof to synthesize the alkali-soluble resin represented by general formula (4) is preferably 20 to 120° C., more preferably 40 to 90° C. The molar ratio of the acid monoanhydride when synthesizing the compound represented by general formula (4) can be changed as desired to adjust the acid value of the alkali-soluble resin represented by general formula (4).

[0081] In this manner, the alkali-soluble resin represented by the general formula (4) can be obtained.

[0082] The alkali-soluble resin represented by general formula (1) is not limited to the alkali-soluble resin obtained by the above-mentioned method. For example, a known naphthalenediol aralkyl resin or biphenyldiol aralkyl resin may be used instead of the biphenol aralkyl resin represented by general formula (7). Alternatively, a known biphenol aralkyl resin obtained by using an aromatic compound other than a biphenyl compound as a crosslinking agent (such as a crosslinking agent used in synthesizing a naphthalenediol aralkyl resin, as described below) may be used instead of the biphenol aralkyl resin represented by general formula (7).

[0083] When a naphthalenediol aralkyl resin is used, various naphthalenediols such as 1,5-naphthalenediol, 1,6-naphthalenediol, 1,7-naphthalenediol, 1,8-naphthalenediol, 2,6-naphthalenediol, and 2,7-naphthalenediol can be used as the material instead of the above-mentioned biphenols.

[0084] Examples of crosslinking agents that can be used when synthesizing naphthalene diol aralkyl resins include halogenated alkyl compounds such as 1,4-bis(chloromethyl)benzene, 1,4-bis(chloroethyl)benzene, 4,4'-bis(chloromethyl)biphenyl, 4,4'-bis(bromomethyl)biphenyl, and 4,4'-bis(chloromethylbiphenyl) ether; alcohols such as p-xylylene glycol, p-di(hydroxyethyl)benzene, 4,4'-bis(hydroxymethyl)biphenyl, 2,6-bis(hydroxymethyl)naphthalene, and 2,2'-bis(hydroxymethyl)diphenyl ether; dialkyl ethers of the above alcohols such as 4,4'-bis(methoxymethyl)biphenyl, 4,4'-bis(ethoxymethyl)biphenyl, and p-xylylene glycol dimethyl ether; and divinyl compounds such as divinylbenzene and divinylbiphenyl.

[0085] When a known biphenol aralkyl resin obtained by using an aromatic compound other than a biphenyl compound as a crosslinking agent is used, an alkali-soluble resin obtained by synthesis in the same manner as the biphenol aralkyl resin represented by general formula (7) can be used, except that the above crosslinking agent (excluding a biphenyl compound) is used. When a naphthalenediol aralkyl resin or a biphenyldiol aralkyl resin is used, the alkali-soluble resin of the present invention can also be obtained by the same method.

[0086] (Method for producing photosensitive resin composition) Next, a method for producing a photosensitive resin composition according to one embodiment of the present invention will be described. The photosensitive resin composition of the present invention contains, in addition to the above-mentioned (i) alkali-soluble resin represented by general formula (1), (ii) a photopolymerizable monomer having at least one polymerizable unsaturated group, and (iii) a photopolymerization initiator. Each component will be described below.

[0087] The photosensitive resin composition contains, as the alkali-soluble resin (i), an alkali-soluble resin represented by the above-mentioned general formula (1). The content of component (i) is preferably 30% by mass or more and 80% by mass or less of the solid content of the photosensitive resin composition (solid content excluding the solvent (solid content includes monomers that become solid content after curing)).

[0088] Examples of the photopolymerizable monomer having at least one polymerizable unsaturated group as component (ii) include monomers having a hydroxyl group such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate; and (meth)acrylic acid esters such as ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, tetramethylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, trimethylolethane tri(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and glycerol (meth)acrylate. When it is necessary to form a crosslinked structure between molecules of an alkali-soluble resin, it is preferable to use a photopolymerizable monomer having two or more polymerizable unsaturated groups, and it is more preferable to use a photopolymerizable monomer having three or more polymerizable unsaturated groups. These compounds may be used alone or in combination of two or more.

[0089] The blending ratio [(i) / (ii)] of the above component (ii) to the alkali-soluble resin (i) [component (i)] is preferably 20 / 80 to 90 / 10, more preferably 40 / 60 to 80 / 20. Here, if the blending ratio of the alkali-soluble resin is sufficiently high, the cured product after the photocuring reaction will be sufficiently hard. Furthermore, since the acid value of the coating film is sufficiently high, it dissolves well in an alkali developer, and the pattern edges in the unexposed areas are less likely to be loose and tend to be sharp. Conversely, if the blending ratio of the alkali-soluble resin is not too high, the proportion of photoreactive functional groups in the resin can be sufficiently increased, allowing for sufficient formation of a crosslinked structure by the photocuring reaction. Furthermore, since the acid value of the resin component is not too high, it is easy to control the solubility in an alkali developer within a predetermined range, and it is easy to form a pattern having a desired line width in the exposed areas, making it less likely for pattern defects to occur.

[0090] Examples of the photopolymerization initiator as component (iii) include acetophenones such as acetophenone, 2,2-diethoxyacetophenone, p-dimethylacetophenone, p-dimethylaminopropiophenone, dichloroacetophenone, trichloroacetophenone, and p-tert-butylacetophenone; alkylphenones such as 1-hydroxycyclohexyl phenyl ketone; benzophenones such as benzophenone, 2-chlorobenzophenone, and p,p'-bisdimethylaminobenzophenone; benzil, benzoin, benzoin methyl ether, and benzoyl benzoates. benzoin ethers such as benzoin isopropyl ether and benzoin isobutyl ether; biimidazole compounds such as 2-(O-chlorophenyl)-4,5-phenylbiimidazole, 2-(O-chlorophenyl)-4,5-di(m-methoxyphenyl)biimidazole, 2-(O-fluorophenyl)-4,5-diphenylbiimidazole, 2-(O-methoxyphenyl)-4,5-diphenylbiimidazole, and 2,4,5-triarylbiimidazole; 2-trichloromethyl-5-styryl-1,3,4-oxadiazole, 2- halomethylthiazole compounds such as trichloromethyl-5-(p-cyanostyryl)-1,3,4-oxadiazole and 2-trichloromethyl-5-(p-methoxystyryl)-1,3,4-oxadiazole; 2,4,6-tris(trichloromethyl)-1,3,5-triazine, 2-methyl-4,6-bis(trichloromethyl)-1,3,5-triazine, 2-phenyl-4,6-bis(trichloromethyl)-1,3,5-triazine, 2-(4-chlorophenyl)-4,6-bis(trichloromethyl)-1,3,5-triazine, 2-( halomethyl-s-triazine compounds such as 4-methoxyphenyl)-4,6-bis(trichloromethyl)-1,3,5-triazine, 2-(4-methoxynaphthyl)-4,6-bis(trichloromethyl)-1,3,5-triazine, 2-(4-methoxystyryl)-4,6-bis(trichloromethyl)-1,3,5-triazine, 2-(3,4,5-trimethoxystyryl)-4,6-bis(trichloromethyl)-1,3,5-triazine, and 2-(4-methylthiostyryl)-4,6-bis(trichloromethyl)-1,3,5-triazine;O-Acyloxime compounds such as 1,2-octanedione, 1-[4-(phenylthio)phenyl]-, 2-(O-benzoyloxime), 1-(4-phenylsulfanylphenyl)butane-1,2-dione-2-oxime-O-benzoate, 1-(4-methylsulfanylphenyl)butane-1,2-dione-2-oxime-O-acetate, and 1-(4-methylsulfanylphenyl)butan-1-one oxime-O-acetate; benzil dimethyl ketal, thioxanthone, 2-chlorothioxanthone, and 2,4-diethylthioxane Examples of photopolymerization initiators include sulfur compounds such as thioxanthone, 2-methylthioxanthone, and 2-isopropylthioxanthone; anthraquinones such as 2-ethylanthraquinone, octamethylanthraquinone, 1,2-benzanthraquinone, and 2,3-diphenylanthraquinone; organic peroxides such as azobisisobutylnitrile, benzoyl peroxide, and cumene peroxide; thiol compounds such as 2-mercaptobenzimidazole, 2-mercaptobenzoxazole, and 2-mercaptobenzothiazole; and tertiary amines such as triethanolamine and triethylamine. These photopolymerization initiators may be used alone or in combination of two or more.

[0091] The content of the photopolymerization initiator (iii) is preferably 0.1 to 10 parts by weight, more preferably 2 to 5 parts by weight, per 100 parts by weight of the combined total of (i) the alkali-soluble resin and (ii) the photopolymerizable monomer. When the amount of photopolymerization initiator added is 0.1 parts by weight or more, sensitivity is sufficiently high. When the amount of photopolymerization initiator added is 10 parts by weight or less, halation, in which the tapered shape (the shape of the developed pattern cross section in the film thickness direction) becomes less sharp and becomes tapered, is less likely to occur. Furthermore, the possibility of decomposition gas generation when exposed to high temperatures in subsequent processes is reduced.

[0092] The photosensitive resin composition according to one embodiment of the present invention may also contain an epoxy compound (iv).

[0093] As the epoxy compound (iv), known compounds commercially available as epoxy resins or the like can be used without any particular limitation. Examples of epoxy resins include bisphenol A epoxy compounds, bisphenol F epoxy compounds, bisphenol S epoxy resins, biphenyl epoxy resins, bisphenol fluorene epoxy compounds, phenol novolac epoxy compounds, cresol novolac epoxy compounds, glycidyl ethers of polyhydric alcohols, glycidyl esters of polycarboxylic acids, polymers containing glycidyl (meth)acrylate units, alicyclic epoxy compounds typified by 3,4-epoxycyclohexanecarboxylic acid [(3,4-epoxycyclohexyl)methyl], 1,2-epoxy-4-(2-oxiranyl)cyclohexane adducts of 2,2-bis(hydroxymethyl)-1-butanol (e.g., "EHPE3150" manufactured by Daicel Corporation), phenyl glycidyl ether, p-butylphenol glycidyl ether, triglycidyl isocyanurate, diglycidyl isocyanurate, epoxidized polybutadiene (e.g., "NISSO-PB·JP-100" manufactured by Nippon Soda Co., Ltd.), and epoxy compounds having a silicone skeleton. These components are preferably compounds having an epoxy equivalent of 100 to 300 g / eq and a number average molecular weight of 100 to 5000. Component (iv) may be used alone or in combination of two or more types. When it is necessary to increase the crosslink density of the alkali-soluble resin, a compound having at least two epoxy groups is preferred.

[0094] The content of the epoxy compound (iv) is preferably 10 to 40 parts by mass per 100 parts by mass of the total of components (i) and (ii). One purpose of adding the epoxy compound is to reduce the amount of carboxyl groups remaining after patterning to improve the reliability of the cured film. By adding 10 parts by mass or more of the epoxy compound, the moisture resistance reliability of the composition when used as an insulating film can be further improved. Furthermore, by adding 40 parts by mass or less of the epoxy compound, the amount of photosensitive groups in the resin component of the photosensitive resin composition can be sufficiently increased, thereby ensuring sufficient sensitivity for patterning.

[0095] The photosensitive resin composition according to one embodiment of the present invention may contain a dispersoid as component (v).

[0096] The dispersoid of component (v) can be any known dispersoid used in photosensitive resin compositions, as long as it has an average particle size of 1 to 1,000 nm (as measured by a laser diffraction / scattering particle size distribution analyzer or a dynamic light scattering particle size distribution analyzer). Examples of dispersoids include organic pigments such as azo pigments, condensed azo pigments, azomethine pigments, phthalocyanine pigments, quinacridone pigments, isoindolinone pigments, isoindoline pigments, dioxazine pigments, threne pigments, perylene pigments, perinone pigments, quinophthalone pigments, diketopyrrolopyrrole pigments, and thioindigo pigments; inorganic pigments such as titanium oxide pigments and composite oxide pigments; pigments (colorants that are substantially insoluble in the medium) such as carbon black pigments; organic fillers such as acrylic polymer particles and urethane polymer particles; inorganic fillers such as silica, talc, mica, glass fiber, carbon fiber, calcium silicate, magnesium carbonate, calcium carbonate, calcium sulfate, and barium sulfate; and metal or metal oxide nanoparticles.

[0097] These (v) dispersoids can be used alone or in combination depending on the desired function of the photosensitive resin composition. Examples of light-shielding resists used in the production of black matrices for color filters include carbon black, titanium black, and black organic pigments. Examples of colored resists used in the production of pixels for color filters include red, orange, yellow, green, blue, and purple organic pigments. Examples of solder resists used in the production of insulating films for printed wiring boards include organic pigments, inorganic pigments, and inorganic fillers. Examples of decorative resists used in the design of the front glass of touch panels include carbon black, titanium black, black organic pigments, and white pigments. Examples of transparent resists with high hardness, high refractive index, and high durability include transparent fillers such as silica and titania. These (v) dispersoids can be selected and used as appropriate.

[0098] Examples of (v) dispersoids that are light-blocking materials include black organic pigments, mixed-color organic pigments, and black inorganic pigments. In this case, the (v) dispersoid (light-blocking material) preferably has excellent insulating properties, heat resistance, light resistance, and solvent resistance, depending on the application. Examples of black organic pigments that are light-blocking materials include perylene black, aniline black, cyanine black, and lactam black. Examples of mixed-color organic pigments that are light-blocking materials include pseudo-black pigments obtained by mixing two or more pigments selected from red, blue, green, purple, yellow, cyanine, magenta, etc. Examples of black inorganic pigments that are light-blocking materials include carbon black, chromium oxide, iron oxide, and titanium black. These (v) dispersoids can be used alone or in combination.

[0099] Examples of organic pigments that can be used as component (v) include, but are not limited to, those with the following color index numbers: Pigment Red 2, 3, 4, 5, 9, 12, 14, 22, 23, 31, 38, 112, 122, 144, 146, 147, 149, 166, 168, 170, 175, 176, 177, 178, 179, 184, 185, 187, 188, 202, 207, 208, 209, 210, 213, 214, 220, 221, 242, 247, 253, 254, 255, 256, 257, 262, 264, 266, 272, 279, etc. Pigment Orange 5, 13, 16, 34, 36, 38, 43, 61, 62, 64, 67, 68, 71, 72, 73, 74, 81 etc. Pigment Yellow 1, 3, 12, 13, 14, 16, 17, 55, 73, 74, 81, 83, 93, 95, 97, 109, 110, 111, 117, 120, 126, 127, 128, 129, 130, 136, 138, 139, 150, 151, 153, 154, 155, 173, 174, 175, 176, 180, 181, 183, 185, 191, 194, 199, 213, 214, etc. Pigment Green 7, 36, 58, etc. Pigment Blue 15, 15:1, 15:2, 15:3, 15:4, 15:6, 16, 60, 80, etc. Pigment Violet 19, 23, 37, etc.

[0100] Furthermore, known rubber components may be added as other dispersoids to improve impact resistance, adhesion to plated metal during processing, etc. The rubber component is preferably a crosslinked elastic polymer having a carboxy group to ensure developability. Examples of rubber components include crosslinked acrylic rubber having a carboxy group, crosslinked NBR having a carboxy group, and crosslinked MBS having a carboxy group. When using a rubber component, it is preferable to add one having an average particle size of 0.1 μm or less in an amount of 3 to 10 parts by mass per 100 parts by mass of the resin component.

[0101] (v) The dispersoid is preferably dispersed in advance in a solvent together with a dispersant to form a dispersion, which is then blended into the photosensitive resin composition. In this case, the solvent to be used may be one of those exemplified as solvents for dissolving the photosensitive resin composition of the present invention, or two or more of them may be used in combination.

[0102] The blending ratio of the dispersoid forming the dispersoid dispersion can be 1 to 95% by mass based on the total solid content of the photosensitive resin composition of the present invention. The solid content refers to the components of the composition excluding the solvent. The solid content also includes component (ii), which becomes solid after photocuring. The wide range of dispersoid addition amount, 1 to 95% by mass, accounts for the use of dispersoids ranging from organic dispersoids with low specific gravity, such as acrylic resin particles or rubber particles, to dispersoids with high specific gravity, such as metal particles or metal oxide particles. Furthermore, when dispersoids are added for coloring purposes, a content of 5 to 80% by mass is preferred. By adding more than 5% by mass of the solid content, it becomes easier to impart the desired coloring and the functions that the dispersoid is intended to impart, such as the desired light-blocking properties. By setting the solid content to 80% by mass or less, the content of the photosensitive resin, which originally serves as a binder, can be sufficiently increased, ensuring developability and film-forming ability. Therefore, when the component (v) in the solid content is a colorant (including a light-shielding material), the content thereof is preferably 10 to 70 mass %, and more preferably 20 to 60 mass %.

[0103] The dispersoid dispersion may contain a known dispersant such as a polymer dispersant to stably disperse the dispersoid. The dispersant may be a known compound used in pigment dispersion (e.g., a compound commercially available under the names of dispersant, dispersing wetting agent, dispersion promoter, etc.).

[0104] Examples of dispersants include cationic polymer dispersants, anionic polymer dispersants, nonionic polymer dispersants, and pigment derivative dispersants (dispersing aids). In particular, the dispersant is preferably a cationic polymer dispersant having a cationic functional group, such as an imidazolyl group, a pyrrolyl group, a pyridyl group, or a primary, secondary, or tertiary amino group, as an adsorption site for the pigment or other dispersoid, and having an amine value of 1 to 100 mgKOH / g and a number-average molecular weight of 1,000 to 100,000. The blending amount of this dispersant is preferably 1 to 35% by mass, more preferably 2 to 25% by mass, relative to the dispersoid. While high-viscosity substances such as resins generally have the effect of stabilizing dispersion, those without the ability to promote dispersion are not considered dispersants. However, this does not limit their use for the purpose of stabilizing dispersion.

[0105] The dispersoid dispersion thus obtained can be made into a photosensitive resin composition containing a dispersoid by mixing it with component (i) (if component (i) was co-dispersed when preparing the dispersoid dispersion, the remaining component (i)), component (ii), component (iii), and optionally added component (iv), and adding a solvent as necessary to adjust the solution viscosity to an appropriate level.

[0106] The photosensitive resin composition according to one embodiment of the present invention may contain a solvent.

[0107] Examples of the solvent include alcohols such as methanol, ethanol, n-propanol, isopropanol, ethylene glycol, and propylene glycol; terpenes such as α- or β-terpineol; ketones such as acetone, methyl ethyl ketone, cyclohexanone, and N-methyl-2-pyrrolidone; aromatic hydrocarbons such as toluene, xylene, and tetramethylbenzene; cellosolve, methyl cellosolve, ethyl cellosolve, carbitol, methyl carbitol, ethyl carbitol, butyl carbitol, propylene glycol monomethyl ether, and propylene glycol monoethyl ether. Examples of suitable acetic acid esters include glycol ethers such as dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, triethylene glycol monomethyl ether, and triethylene glycol monoethyl ether; and acetate esters such as ethyl acetate, butyl acetate, cellosolve acetate, ethyl cellosolve acetate, butyl cellosolve acetate, carbitol acetate, ethyl carbitol acetate, butyl carbitol acetate, propylene glycol monomethyl ether acetate, and propylene glycol monoethyl ether acetate. These can be dissolved and mixed alone or in combination of two or more to form a uniform solution composition.

[0108] The photosensitive resin composition of the present invention may contain additives such as a curing agent, a curing accelerator, a thermal polymerization inhibitor, an antioxidant, a chain transfer agent, a plasticizer, a leveling agent, an antifoaming agent, a coupling agent, a surfactant, an ultraviolet absorber, etc. Furthermore, in order to control the properties of the cured product, resins such as vinyl resins, polyester resins, polyamide resins, polyimide resins or precursors thereof, polybenzoxazole resins or precursors thereof, polyurethane resins, polyether resins, and melamine resins may also be added.

[0109] The curing agent may be, for example, a known compound known as a curing agent normally used for epoxy compounds, including amine compounds, polycarboxylic acid compounds, amino resins, dicyandiamide, Lewis acid complex compounds, phenolic resins, etc.

[0110] Examples of the curing accelerator include known compounds commonly used in epoxy compounds, such as curing accelerators, curing catalysts, and latent curing agents. Examples of curing accelerators include tertiary amines, quaternary ammonium salts, tertiary phosphines, quaternary phosphonium salts, borate esters, Lewis acids, organometallic compounds, imidazoles, and diazabicyclo compounds. Examples of thermal polymerization inhibitors and antioxidants include hydroquinone, hydroquinone monomethyl ether, pyrogallol, tert-butylcatechol, phenothiazine, hindered phenol antioxidants, and phosphorus-based thermal stabilizers. Examples of chain transfer agents include mercaptan compounds, halogen-based compounds, quinone compounds, and α-methylstyrene dimer. Examples of plasticizers include dibutyl phthalate, dioctyl phthalate, and tricresyl phosphate. Examples of antifoaming agents and leveling agents include silicone-based, fluorine-based, and acrylic compounds. Examples of coupling agents include vinyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-(glycidyloxy)propyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, 3-aminopropyltriethoxysilane, 3-(phenylamino)propyltrimethoxysilane, 3-ureidopropyltriethoxysilane, etc. Examples of surfactants include fluorine-based surfactants, silicone-based surfactants, etc. Examples of ultraviolet absorbers include benzotriazole compounds, benzophenone compounds, triazine compounds, etc.

[0111] The photosensitive resin composition of the present invention preferably contains at least 70 mass %, more preferably at least 80 mass %, and even more preferably at least 90 mass % of (i) the alkali-soluble resin represented by general formula (1), (ii) the photopolymerizable monomer, (iii) the photopolymerization initiator, and optional components (iv) the epoxy compound and (v) the dispersoid in a total amount of 70 mass % or more, more preferably at least 80 mass %, and even more preferably at least 90 mass % or more of the solid content excluding the solvent (the solid content includes the monomers that become solid after curing). The amount of solvent varies depending on the target viscosity, but is preferably 10 to 80 mass % of the total amount.

[0112] In this manner, the photosensitive resin composition of the present invention can be obtained.

[0113] The photosensitive resin composition containing the alkali-soluble resin represented by general formula (1) produced as described above can provide cured films that have excellent heat resistance, dimensional accuracy, and pattern cross-sectional shape, which are formed by photolithography for use in solder resists, plating resists, and etching resists for producing circuit boards, as well as color filters and light-shielding films for liquid crystal display devices, organic EL display devices, μLED display devices, image sensors, and the like.

[0114] Each step of the method for forming a coating film (cured product) by coating and drying a photosensitive resin composition will now be specifically illustrated.

[0115] The coating film (cured product) of the present invention can be obtained, for example, by applying a solution of the photosensitive resin composition to a substrate or the like, drying it, and curing it by irradiating it with light (including ultraviolet rays, radiation, etc.). A photomask or the like is used to define areas that are exposed to light and areas that are not, and only the areas that are exposed to light are cured while the other areas are dissolved in an alkaline solution, thereby obtaining a coating film with a desired pattern.

[0116] Specific examples of the steps of the film-forming method by coating and drying a photosensitive resin composition include applying the photosensitive resin composition to a substrate using any of the known methods, such as solution immersion, spraying, roller coater, land coater, slit coater, or spinner. After applying the composition to a desired thickness using these methods, a coating is formed by removing the solvent (prebaking). Prebaking is performed by heating in an oven or hot plate, vacuum drying, or a combination of these. The heating temperature and heating time in prebaking are appropriately selected depending on the solvent used, and are, for example, performed at 80 to 120°C for 1 to 10 minutes.

[0117] Radiation used for exposure can be, for example, visible light, ultraviolet light, far ultraviolet light, electron beams, or X-rays, with the wavelength of the radiation preferably ranging from 250 to 450 nm. Examples of developers suitable for this alkaline development include aqueous solutions of sodium carbonate, potassium carbonate, potassium hydroxide, diethanolamine, tetramethylammonium hydroxide, and the like. These developers can be selected appropriately depending on the characteristics of the resin layer, and adding a surfactant is also effective if necessary. The development temperature is preferably 20 to 35°C, and fine images can be precisely formed using a commercially available developing machine or ultrasonic cleaner. After alkaline development, the film is usually washed with water. Examples of development methods that can be used include shower development, spray development, dip (immersion) development, and puddle (puddle) development.

[0118] After development in this manner, a heat treatment (post-baking) is carried out at 180 to 250°C for 20 to 100 minutes. This post-baking is carried out for purposes such as increasing the adhesion between the patterned coating film and the substrate. As with pre-baking, this is carried out by heating using an oven, hot plate, or the like. The patterned coating film of the present invention is formed through the above-mentioned steps of the photolithography method. Then, polymerization or curing (sometimes collectively referred to as curing) is completed by heat to form a cured film pattern. The curing temperature at this time is preferably 160 to 250°C.

[0119] The photosensitive resin composition of the present invention has a larger number of polymerizable unsaturated groups than conventional compositions, resulting in improved photocurability and a higher crosslink density after curing without increasing the amount of photopolymerization initiator. Specifically, when a thick film is irradiated with ultraviolet light or an electron beam, the cured portion is cured to the bottom, eliminating the difference in solubility in alkaline developer between the exposed and unexposed portions. This improves pattern dimensional stability, development margin, and pattern adhesion, enabling high-resolution pattern formation. Furthermore, even in the case of a thin film, the increased sensitivity significantly improves the remaining film thickness in the exposed area and suppresses peeling during development.

[0120] The photosensitive composition of the present invention is extremely useful as a solder resist, plating resist, or etching resist for producing circuit boards, an insulating film for multilayering wiring boards on which semiconductor elements are mounted, various insulating films for semiconductor devices, gate insulating films for semiconductors, and photosensitive adhesives (particularly adhesives that require heat adhesion properties even after pattern formation by photolithography). [Example]

[0121] Hereinafter, the present invention will be described in detail based on examples and comparative examples, but the present invention is not limited to these. In the present invention, when the first decimal place of the content of each component is 0, the decimal point may be omitted.

[0122] First, we will explain the synthesis examples of the alkali-soluble resin containing a polymerizable unsaturated group represented by general formula (1), which is component (i). Unless otherwise specified, the resins in these synthesis examples were evaluated as follows.

[0123] [Solid content concentration] The resin solutions, photosensitive resin compositions, etc. (1 g) obtained in Synthesis Examples 1 and 2 and Comparative Synthesis Example were impregnated into a glass filter (mass: W0 (g)), weighed [W1 (g)], and calculated from the mass [W2 (g)] after heating at 160°C for 2 hours using the formula below. Solid content concentration (mass%) = 100 × (W2-W0) / (W1-W0)

[0124] [Acid value] The acid value was determined by dissolving the resin solution in tetrahydrofuran and titrating it with a 1 / 10N KOH aqueous solution using a potentiometric titrator "COM-1600" (manufactured by Hiranuma Sangyo Co., Ltd.), and the amount of KOH required per 1 g of solid content was taken as the acid value.

[0125] [Molecular weight] The molecular weight was measured by gel permeation chromatography (GPC) ("HLC-8320GPC" manufactured by Tosoh Corporation, columns: TSKgelSuperH2000 (2 columns) + TSKgelSuperH3000 (1 column) + TSKgelSuperH4000 (1 column) + TSKgelSuperH5000 (1 column) (all manufactured by Tosoh Corporation), solvent: tetrahydrofuran, temperature: 40°C, rate: 0.6 ml / min), and the value calculated as a standard polystyrene ("PS-oligomer kit" manufactured by Tosoh Corporation) was used as the weight average molecular weight (Mw).

[0126] The abbreviations used in Synthesis Examples 1 to 3 and Comparative Synthesis Examples are as follows: BPAEA: A compound obtained by reacting an epoxy compound (epoxy equivalent: 199 g / eq, in general formula (8), where W is a glycidyl group) obtained by reacting a reaction product of 4,4'-biphenol and 4,4'-bischloromethylbiphenyl (biphenyl aralkyl resin) with epichlorohydrin, and then reacting the epoxy compound with acrylic acid (equivalent reaction product of epoxy groups and carboxy groups). BNAEA: A compound (equivalent reaction product of epoxy and carboxyl groups) obtained by reacting epichlorohydrin with a reaction product of 1,6-dihydroxynaphthalene and p-xylylene glycol dimethyl ether (naphthalenediol aralkyl resin) to obtain an epoxy compound (epoxy equivalent 166) and then reacting it with acrylic acid. BPDA: 3,3',4,4'-biphenyltetracarboxylic dianhydride THPA: 1,2,3,6-tetrahydrophthalic anhydride SA: Succinic anhydride TEAB: Tetraethylammonium bromide PGMEA: Propylene glycol monomethyl ether acetate

[0127] The following Synthesis Examples 1 and 2 are synthesis examples of alkali-soluble resins having a carboxy group and a polymerizable unsaturated group in one molecule, as represented by general formula (1). The comparative synthesis example is a polymerizable unsaturated group-containing alkali-soluble resin having a skeleton different from that of the alkali-soluble resin represented by general formula (1), which is an epoxy acrylate acid adduct of a bisphenol A epoxy compound. The following Synthesis Example 3 is a synthesis example of an alkali-soluble resin having a carboxy group and a polymerizable unsaturated group in one molecule, as represented by general formula (1).

[0128] [Synthesis Example 1] (Synthesis of alkali-soluble resin (i)-1 represented by general formula (1)) A 1000 ml four-neck flask equipped with a reflux condenser was charged with 419.6 g of a 50% BPAEA solution in PGMEA, 88.3 g of THPA, 1.63 g of TEAB, and 29.2 g of PGMEA, and the mixture was stirred at 120-125°C for 6 hours to obtain alkali-soluble resin (i)-1. The solids concentration of the resulting resin was 56.2 wt%, the acid value (solids equivalent) was 113.6 mg KOH / g, and the molecular weight (Mw) by GPC analysis was 3410.

[0129] [Synthesis Example 2] (Synthesis of alkali-soluble resin (i)-2 represented by general formula (1)) A 1000 ml four-neck flask equipped with a reflux condenser was charged with 419.6 g of a 50% PGMEA solution of BPAEA, 58.1 g of SA, 1.63 g of TEAB, and 5.2 g of PGMEA, and the mixture was stirred at 120-125°C for 6 hours to obtain alkali-soluble resin (i)-2. The solids concentration of the resulting resin was 56.1 wt%, the acid value (solids equivalent) was 125.7 mg KOH / g, and the molecular weight (Mw) by GPC analysis was 3220.

[0130] [Comparative synthesis example] (Synthesis of alkali-soluble resin (i)-3) A 1000 ml four-neck flask equipped with a reflux condenser was charged with 442.0 g of a 50% PGMEA solution (480 g / eq) of a bisphenol A epoxy compound (epoxy equivalent) and acrylic acid, 20.6 g of BPDA, 24.3 g of THPA, 0.84 g of TEAB, and 12.0 g of PGMEA. The mixture was stirred at 120-125°C for 6 hours to obtain alkali-soluble resin solution (i)-3. The solids concentration of the resulting resin was 56.1 wt%, the acid value (solids equivalent) was 62.7 mg KOH / g, and the molecular weight (Mw) by GPC analysis was 9000.

[0131] [Synthesis Example 3] (Synthesis of alkali-soluble resin (i)-4 represented by general formula (1)) A 1000 ml four-neck flask equipped with a reflux condenser was charged with a 50% BNAEA solution in PGMEA (368.5 g), THPA (88.3 g), TEAB (1.63 g), and PGMEA (54.7 g), and the mixture was stirred at 120-125°C for 6 hours to obtain alkali-soluble resin (i)-4. The solids concentration of the resulting resin was 57.0 wt%, the acid value (solids equivalent) was 126.6 mg KOH / g, and the molecular weight (Mw) by GPC analysis was 2990. The resulting compound was a compound of general formula (1), where X1 is a tetravalent naphthalene ring, Y1 is a xylylene group, and Q1 are both hydrogen atoms. In addition, all V1s have a structure in which, in general formula (2), R1 is a hydrogen atom, L is general formula (3), and in general formula (3), M is a cyclohexene-1,2-diyl group (residue of 1,2,3,6-tetrahydrophthalic acid), and p=1.

[0132] [Experiment 1] In Experiment 1, the heat resistance of the alkali-soluble resin represented by general formula (1) and the cured film of the photosensitive resin composition containing the same was evaluated.

[0133] [evaluation] [Heat resistance evaluation] Substrates with cured films of alkali-soluble resins (i)-1 to (i)-3 to be used in heat resistance evaluation 1 and heat resistance evaluation 2 were prepared as follows.

[0134] (Preparation of substrates with cured films for heat resistance evaluation 1 and heat resistance evaluation 2) Five grams of the alkali-soluble resins ((i)-1 to (i)-3) obtained in Synthesis Examples 1 and 2 and Comparative Synthesis Example were each diluted with 5 g of acetone, and then thinly spread on a 125 mm x 125 mm glass substrate "#1737" (manufactured by Corning Incorporated) and dried at 110°C for 60 minutes to obtain substrates with cured films for heat resistance evaluation 1 and heat resistance evaluation 2.

[0135] (Evaluation method) The heat resistance of the cured film was evaluated by measuring the weight change under atmospheric conditions using a thermogravimetric-differential thermal analyzer (TG-DTA). The measurement was performed by scraping off the cured film from the glass substrate. The measurement conditions are shown in Table 1.

[0136] [Table 1]

[0137] The results of heat resistance evaluation 1 and heat resistance evaluation 2 of the above cured film are shown in Tables 2 and 3.

[0138] [Table 2]

[0139] [Table 3]

[0140] As shown in Tables 2 and 3, it was found that the cured product of the alkali-soluble resin having a polymerizable unsaturated group represented by general formula (1) had high heat resistance.

[0141] Next, photosensitive resin compositions of Examples 1 and 2 were prepared in the amounts (unit: mass %) shown in Table 4. The ingredients used in Table 4 are as follows.

[0142] (Polymerizable unsaturated group-containing alkali-soluble resin) (i)-1: Alkali-soluble resin containing polymerizable unsaturated groups obtained in Synthesis Example 1 (i)-2: Alkali-soluble resin containing polymerizable unsaturated groups obtained in Synthesis Example 2 (Photopolymerizable monomer) (ii) : Dipentaerythritol hexaacrylate (Photopolymerization initiator) (iii): 1-hydroxycyclohexyl phenyl ketone (trade name: Omnirad184, manufactured by IGM Resins BV) (solvent) PGMEA

[0143] [Table 4]

[0144] A substrate with a cured film of a photosensitive resin composition containing an alkali-soluble resin ((i)-1 or (i)-2) for use in heat resistance evaluation 3 was prepared as follows.

[0145] (Preparation of substrate with cured film for heat resistance evaluation 3) The photosensitive resin compositions containing the alkali-soluble resins ((i)-1 or (i)-2) shown in Table 4 were each applied to a glass substrate using a spin coater so that the film thickness after post-baking would be 1.0 to 1.5 μm, and the substrate was pre-baked at 90°C for 1 minute to prepare a coated plate. 2 The entire surface was irradiated with ultraviolet light of 365 nm wavelength from a high-pressure mercury lamp to carry out a photo-curing reaction. Further, a heat-curing treatment was carried out at 230°C for 30 minutes using a hot air dryer to obtain a cured film for heat resistance evaluation 3.

[0146] (Evaluation method) The heat resistance of the obtained cured film for heat resistance evaluation 3 was evaluated in the same manner as in the heat resistance evaluation described above. The cured film on the glass substrate was scraped off and used for the measurement. The measurement conditions are shown in Table 5.

[0147] [Table 5]

[0148] The results of the heat resistance evaluation 3 are shown in Table 6.

[0149] [Table 6]

[0150] As shown in Table 6, it was found that the photosensitive resin composition containing the alkali-soluble resin represented by general formula (1) had high heat resistance.

[0151] [Experiment 2] In Experiment 2, various properties required when a photosensitive resin composition containing an alkali-soluble resin represented by general formula (1) is used for an insulating film or the like were evaluated.

[0152] Photosensitive resin compositions of Examples 3 to 5 and Comparative Example 2 were prepared in the amounts (unit: mass %) shown in Table 7. The ingredients used in Table 7 are as follows.

[0153] (Polymerizable unsaturated group-containing alkali-soluble resin) (i)-1: Alkali-soluble resin obtained in Synthesis Example 1 (i)-2: Alkali-soluble resin obtained in Synthesis Example 2 (i)-3: Alkali-soluble resin obtained in Comparative Synthesis Example 1 (i)-4: Alkali-soluble resin obtained in Synthesis Example 3 (Photopolymerizable monomer) (ii): Dipentaerythritol hexaacrylate (Photopolymerization initiator) (iii)-1: Omnirad 184 (manufactured by IGM RESINS BV) (iii)-2: p,p'-bis(dimethylamino)benzophenone (Michler's ketone) (epoxy resin) (iv): Cresol novolac epoxy resin (YDCN-700-7, epoxy equivalent 200 g / eg, softening point 70°C, manufactured by Nippon Steel Chemical & Material Co., Ltd.) (solvent) PGMEA

[0154] [Table 7]

[0155] [Evaluation of Photosensitive Resin Compositions of Examples 3 to 5 and Comparative Example 2] The photosensitive resin compositions shown in Table 7 were applied to a 125 mm × 125 mm glass substrate using a spin coater so that the film thickness after post-baking would be 10 μm, and the substrate was pre-baked at 90°C for 3 minutes to prepare a coated plate. Then, the coated plate was exposed to a 500 W / cm 2 photoirradiation through a photomask for pattern formation. 2 The exposed plate was irradiated with ultraviolet light of 365 nm wavelength from a high-pressure mercury lamp, and a photo-curing reaction was carried out in the exposed area. Next, the exposed plate was developed for an additional 20 seconds from the time when the pattern began to appear using a 1.0 wt% aqueous sodium carbonate solution at 23°C for shower development, and then spray-washed with water to remove the unexposed areas of the coating. Subsequently, a heat-curing treatment was carried out using a hot air dryer at 230°C for 30 minutes, yielding cured films according to Examples 1 to 3 and Comparative Example 2.

[0156] The cured film was evaluated as follows, and the results are shown in Table 8.

[0157] (sensitivity) The photosensitive resin compositions shown in Table 7 were applied to a 125 mm × 125 mm glass substrate using a spin coater so that the film thickness after post-baking would be 10 μm, and the substrate was pre-baked at 90°C for 3 minutes to prepare a coated plate. The coated plate was then exposed to 500 W / cm 2 light through a photomask whose transmittance was continuously changed from 0% to 100%. 2The exposed area was irradiated with ultraviolet light of 365 nm wavelength from a high-pressure mercury lamp, and a photo-curing reaction was carried out in the exposed area. Next, the exposed coated plate was developed for an additional 10 seconds from the time when the pattern began to appear using a 1.0 wt% aqueous sodium carbonate solution at 23°C for shower development, and then spray-washed with water to remove the unexposed areas of the coating. The plate was then subjected to a heat-curing treatment at 230°C for 30 minutes using a hot air dryer, and the minimum exposure dose (mJ / cm) at which a cured film remained was determined. 2 ) was calculated.

[0158] (Method for measuring adhesion and residue) The adhesion of the cured film to the fine line pattern was confirmed using a digital microscope "VHX5000" (manufactured by KEYENCE Corporation) and evaluated according to the following criteria.

[0159] The evaluation criteria for adhesion are as follows: ○: A pattern with an L / S (line width / space width) of 30 μm / 30 μm or more is formed ×: No pattern with L / S (line width / space width) of less than 30 μm / 30 μm is formed

[0160] The residue evaluation criteria are as follows: ○: No residue between patterns in patterns with L / S (line width / space width) of 30 μm / 30 μm or more ×: Residue is noticeable between patterns in patterns with an L / S (line width / space width) of 30 μm / 30 μm or more.

[0161] (Linearity measurement method) The linearity of the fine line pattern on the cured film was confirmed using a digital microscope "VHX5000" (manufactured by KEYENCE Corporation) and evaluated according to the following criteria. ○: No peeling or chipping of the fine line pattern from the glass substrate, and no jagged edges of the pattern were observed. ×: Peeling or chipping of the fine line pattern from the glass substrate, or jagged edges of the pattern are observed

[0162] (Tapered shape) The tapered shape was evaluated using a negative photomask with a line and space pattern of 1 to 100 μm, and the exposed and developed pattern was observed using a scanning electron microscope "VE-7800" (manufactured by KEYENCE Corporation) and evaluated according to the following criteria. ◎: Cross-sectional shape is nearly vertical ○: The cross-sectional shape is trapezoidal, and the inner angle of the pattern end formed by the pattern side surface and the glass substrate is 90° to 60° △: The cross-sectional shape is smooth and round ×: The cross-sectional shape is trapezoidal, and the inner angle of the pattern end formed by the pattern side surface and the glass substrate is greater than 90°

[0163] [Table 8]

[0164] As shown in Table 8, the photosensitive resin compositions containing the alkali-soluble resins prepared in Examples 3 to 5 exhibit both high adhesion and reduced residue, and are capable of forming cured film patterns with excellent tapered shapes.

[0165] As described above, the photosensitive resin composition containing the alkali-soluble resin of the present invention can be used in a variety of applications, including solder resists, plating resists, and etching resists for producing circuit boards, as well as in applications requiring the formation of cured films having excellent dimensional accuracy and pattern cross-sectional shapes formed by photolithography, such as color filters and light-shielding films for liquid crystal display devices, organic EL display devices, μLED display devices, image sensors, and the like.

[0166] This application claims priority from Japanese Patent Application No. 2020-182575, filed October 30, 2020. The entire contents of the specification and claims of that application are incorporated herein by reference. [Industrial Applicability]

[0167] The photosensitive resin composition containing the alkali-soluble resin of the present invention can be used as a solder resist, plating resist, etching resist for producing circuit boards, or resist for insulating films in semiconductor devices, etc., and the cured product thereof can be used as various cured films formed by photolithography, such as protective films, color filters, and light-shielding films, which are components of liquid crystal display devices, organic EL display devices, μLED display devices, image sensors, etc.

Claims

1. An alkali-soluble resin having a carboxy group and a polymerizable unsaturated group in one molecule, represented by the following general formula (1): 【Chemistry 1】 (In formula (1), X １ represents a tetravalent aromatic ring-containing group, Y １ represents a divalent aromatic ring-containing group. １ and Y １ A part of the hydrogen atoms of may be substituted with a linear or branched hydrocarbon group having 1 to 20 carbon atoms. １ is a substituent represented by the following general formula (2). The average value of l is 0.2 to 4.

0. １ is a hydrogen atom or a straight or branched chain hydrocarbon group having 1 to 20 carbon atoms. 【Chemistry 2】 (In formula (2), R １ represents a hydrogen atom or a methyl group. L represents a substituent represented by the following general formula (3). * represents the bonding site with the oxygen atom (O) in formula (1). 【Transformation 3】 (In formula (3), M represents a divalent or trivalent residue derived from a dicarboxylic acid, a tricarboxylic acid, or an acid monoanhydride thereof, and p is 1 or 2. * represents the bonding site with the oxygen atom (O) in formula (2).)

2. X １ is a tetravalent substituent represented by the following general formula (5), and Y １ is a divalent substituent represented by the following general formula (6), and in the following general formulas (5) and (6), some of the hydrogen atoms may be substituted with a linear or branched hydrocarbon group having 1 to 20 carbon atoms. 【Chemistry 4】 (In formula (5), * represents an oxygen atom (O) in formula (1), Y １ or Q １ The binding site is shown.) 【Transformation 5】 (In formula (6), * represents X in formula (1) １ The binding site is shown.)

3. X １ The alkali-soluble resin according to claim 1 , wherein R is a tetravalent substituent derived from naphthalenediol.

4. (i) the alkali-soluble resin according to any one of claims 1 to 3; (ii) a photopolymerizable monomer having at least one polymerizable unsaturated group; (iii) a photopolymerization initiator; and A photosensitive resin composition comprising as an essential component:

5. 5. The photosensitive resin composition according to claim 4, wherein the content of the component (iii) is 0.1 to 10 parts by mass per 100 parts by mass of the total of the component (i) and the component (ii).

6. The photosensitive resin composition according to claim 4 or 5, further comprising (iv) an epoxy compound.

7. 7. The photosensitive resin composition according to claim 6, wherein the content of the component (iv) is 10 to 40 parts by mass per 100 parts by mass of the total of the component (i) and the component (ii).

8. The photosensitive resin composition according to any one of claims 4 to 7, further comprising (v) a dispersoid.

9. A cured product obtained by curing the photosensitive resin composition according to any one of claims 4 to 8.

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