TWI902956B - Alkali-soluble resins containing polymerizable unsaturated groups, photosensitive resin compositions with such resins as essential components, and their cured forms. - Google Patents

Abstract

Alkali-soluble resins represented by general formula (1) possess a carboxyl group and a polymerizable unsaturated group within a single molecule.

In formula (1), _X1 represents a tetravalent aromatic ring group, _Y1 represents a divalent aromatic ring group, and some of the hydrogen atoms in _X1 and _Y1 can also be substituted by a straight-chain or branched hydrocarbon group with 1 to 20 carbon atoms. _V1 is the substituent represented by general formula (2), with an average value of 0.2 to 4.0. _Q1 is a hydrogen atom or a straight-chain or branched hydrocarbon group with 1 to 20 carbon atoms. In formula (2), _R1 represents a hydrogen atom or a methyl group, L represents the substituent represented by general formula (3), and * represents the site of bonding with the oxygen atom (O) in formula (1). In formula (3), M represents a divalent or trivalent residual group derived from dicarboxylic acid, tricarboxylic acid, or their anhydrides, p is 1 or 2, and * represents the site of bonding with the oxygen atom (O) in formula (2).

Description

Alkali-soluble resins containing polymerizable unsaturated groups, photosensitive resin compositions containing such resins as essential components, and their cured forms.

This invention relates to an alkali-soluble resin containing polymerizable unsaturated groups, a photosensitive resin composition comprising the resin as an essential component, and its cured form.

With the increasing performance and precision of electronic devices and display components in recent years, there is a growing demand for miniaturization and high density of the electronic parts used in them. Furthermore, the processability of the insulating materials used in these devices also requires miniaturization and optimization of the cross-sectional shape of the processed patterns. Effective methods for the micro-processing of insulating materials include patterning methods using exposure and development, which utilize photosensitive resin compositions and require numerous properties such as high sensitivity, good adhesion to the substrate, reliability, heat resistance, and chemical resistance.

Previous insulating materials containing photosensitive resin compositions utilized a photocuring reaction caused by the reaction of a photoreactive alkali-soluble resin with a photopolymerization initiator. The exposure wavelength used for photocuring was primarily the i-ray (365 nm), one of the line spectra of a mercury lamp. However, this i-ray is absorbed by the photosensitive resin itself or by the colorant, leading to a decrease in photocurability. Furthermore, the absorption increases with the thickness of the film. Consequently, the exposed areas exhibit differences in crosslink density relative to the film thickness. Therefore, even if sufficient photocuring occurs on the coating surface, photocuring is difficult on the underside of the coating, making it significantly difficult to create a difference in crosslink density between the exposed and unexposed areas. Therefore, it is difficult to obtain insulating materials containing photosensitive resin compositions that can develop images with high resolution, exhibiting the desired pattern dimensional stability, development margin, pattern adhesion, pattern edge shape, and cross-sectional shape.

Generally, photosensitive resin compositions for this purpose are suitable for use with multifunctional photocurable monomers containing polymerically unsaturated bonds, alkali-soluble adhesive resins, photopolymerization initiators, etc., and photosensitive resin compositions disclosed in the art that can be used as materials for color filters. For example, Patents 1 and 2 disclose copolymers of carboxyl-containing (meth)acrylic acid or (meth)acrylate, maleic anhydride, and other polymeric monomers as adhesive resins.

Furthermore, Patent 3 discloses that alkali-soluble unsaturated compounds containing polymerizable unsaturated groups and carboxyl groups in a single molecule are effective for forming negative patterns such as color filters.

On the other hand, patents 4, 5, 6, and 7 disclose liquid resins using the reaction products of epoxy (meth)acrylates with bisphenol fluorene structures and acid anhydrides.

Furthermore, patents 8, 9, and 10 disclose alkali-developing unsaturated resin compositions formed by copolymerizing dihydroxypropyl acrylate with dianhydride, or alkali-developing unsaturated resin compositions formed by copolymerizing dianhydride and dihydroxypropyl acrylate. In these cases, oligomers are obtained by copolymerizing dianhydride with dihydroxypropyl acrylate.

Furthermore, Patent 11 discloses the multifunctionalization of alkali-soluble resin compositions that increases the molecular weight of carboxyl-containing copolymers.

[Existing technical literature] [Patent Documents]

[Patent Document 1] Japanese Patent Application Publication No. Sho 61-213213

[Patent Document 2] Japanese Patent Application Publication No. Hei 1-152449

[Patent Document 3] Japanese Patent Application Publication No. Hei 4-340965

[Patent Document 4] Japanese Patent Application Publication No. Hei 4-345673

[Patent Document 5] Japanese Patent Application Publication No. Hei 4-345608

[Patent Document 6] Japanese Patent Application Publication No. Hei 4-355450

[Patent Document 7] Japanese Patent Application Publication No. Hei 4-363311

[Patent Document 8] Japanese Patent Application Publication No. Hei 5-339356

[Patent Document 9] Japanese Patent Application Publication No. Hei 7-3122

[Patent Document 10] International Publication No. 94/00801

[Patent Document 11] Japanese Patent Application Publication No. Hei 9-325494

However, the copolymers disclosed in Patents 1 and 2 are random copolymers, resulting in varying alkali dissolution rates in the light-irradiated and unirradiated areas. This narrows the margin during development, making it difficult to obtain sharp-angled patterns or fine textures.

Furthermore, the alkali-soluble unsaturated compound described in Patent 3 does not dissolve upon light irradiation, thus it is predicted to have higher sensitivity compared to the combination of the aforementioned adhesive resin and multifunctional polymerizable monomers. Here, examples of compounds described in Patent 3 include compounds formed by the arbitrary addition of polymerizable unsaturated groups to the hydroxyl groups of phenol oligomers with acrylic acid and acid anhydrides. In the compound of Patent 3, a wide distribution exists in the molecular weight and amount of carboxyl groups of each molecule, thus broadening the distribution of the alkali dissolution rate of the alkali-soluble resin, making it difficult to form fine negative patterns.

Furthermore, the resin examples described in patents 4, 5, 6, and 7 include reaction products of epoxy (meth)acrylates and acid monohydric anhydrides. These products have small molecular weights, making it difficult to increase the difference in alkali solubility between the exposed and unexposed areas, thus preventing the formation of fine patterns.

Furthermore, the copolymers described in patents 8, 9, 10, and 11 have a low number of polymerically unsaturated bonds, thus preventing the achievement of sufficient crosslinking density. Therefore, there is room for improvement in the copolymer structure, such as increasing the proportion of polymerically unsaturated bonds per molecule.

Furthermore, photosensitive resin compositions are expected to exhibit minimal deformation of the pattern cross-sectional shape after the thermosetting step following exposure and development, i.e., high heat resistance, in applications such as corrosion inhibitors for various color filters or insulation films in semiconductor devices. Particularly important is the need for minimal change in pattern size due to overheating, particularly when forming fine line patterns smaller than 10 μm or via patterns with a diameter of 50 μm or less, maintaining a rectangular pattern shape.

Alternatively, the photosensitive resin composition of the hardened film used in the manufacture of insulating films, etc., must balance high adhesion to the substrate with residue suppression, and be able to form near-rectangular patterns.

The purpose of this invention is to provide a photosensitive resin composition and its cured form, which exhibits high heat resistance and can maintain a rectangular cross-sectional shape without overheating, or simultaneously achieves high adhesion to the substrate and residue suppression, and can form near-rectangular patterns. Furthermore, another objective of this invention is to provide a technique particularly effective for situations requiring stringent heat resistance properties in the cured form.

The inventors have conducted intensive research to solve the aforementioned problems and have discovered that photosensitive resin compositions using alkali-soluble resins containing polymerizable unsaturated groups are suitable for the formation of photo-patterned curing films with excellent heat resistance. These alkali-soluble resins containing polymerizable unsaturated groups are produced by reacting carboxyl-containing (meth)acrylates with a resin of the following form (a family resin of so-called phenolic aralkyl resins). A polyol compound having polymerizable unsaturated groups is obtained by reacting a dicarboxylic acid, tricarboxylic acid, or their monohydric anhydride with the obtained polyol compound having polymerizable unsaturated groups. The above resin is a resin in the form of an aromatic compound having two hydroxyl groups (such as compounds with two phenolic hydroxyl groups directly bonded to the aromatic ring, like biphenol or naphthol) bonded to a divalent aromatic ring group.

The alkali-soluble resin of this invention is represented by the following general formula (1) and has a carboxyl group and a polymerizable unsaturated group within one molecule.

In formula (1), _X1 represents a tetravalent aromatic ring group, _Y1 represents a divalent aromatic ring group, and some of the hydrogen atoms in _X1 and _Y1 can also be substituted by a straight-chain or branched hydrocarbon group with 1 to 20 carbon atoms. _V1 is the substituent represented by the following general formula (2), and the value of l as the average value is 0.2 to 4.0. _Q1 is a hydrogen atom or a straight-chain or branched hydrocarbon group with 1 to 20 carbon atoms.

In formula (2), _R1 represents a hydrogen atom or a methyl group, L represents a substituent represented by the general formula (3) below, and * represents the site bonded to the oxygen atom (O) in formula (1).

In formula (3), M represents a divalent or trivalent residual group derived from a dicarboxylic acid, tricarboxylic acid, or an anhydride thereof, p is 1 or 2, and * indicates the site of bonding with the oxygen atom (O) in formula (2).

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

The cured material of this invention is formed by curing the aforementioned photosensitive resin composition.

According to the present invention, a photosensitive resin composition and its cured form are provided, comprising an alkali-soluble resin containing a carboxyl group and a polymerizable unsaturated group within a molecule, as represented by general formula (1), exhibiting high heat resistance and maintaining a rectangular cross-sectional shape without overheating. Alternatively, it can achieve both high adhesion to the substrate and residue suppression, and can form near-rectangular patterns. Furthermore, it provides a technique effective for applications requiring stringent heat resistance properties in the cured form.

The embodiments of this invention are described below, but are not limited thereto. Furthermore, in this invention, when the first decimal place of the content of each component is 0, the description below the decimal point is often omitted.

The photosensitive resin composition of one embodiment of the present invention contains (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 as essential components. The components are described below.

[Alkali-soluble resin]

The following explains the alkali-soluble resin represented by general formula (1).

The alkaline soluble resin represented by general formula (1) has a carboxyl group and a polymerizable unsaturated group within one molecule. It can be obtained by reacting an epoxy compound with two or more glycidyl ether groups with a carboxylic acid compound with an unsaturated group, such as (meth)acrylic acid, to obtain a polyol compound containing a polymerizable unsaturated group, and then reacting a dicarboxylic acid, a tricarboxylic acid, or its anhydride with the obtained polyol compound containing a polymerizable unsaturated group. The aforementioned epoxy compounds with two or more glycidyl ether groups are obtained by reacting cyclic ether compounds such as epichlorohydrin with resins in the form of aromatic compounds (such as biphenol or naphthol, which have two phenolic hydroxyl groups directly bonded to the aromatic ring) that are divalent and contain aromatic ring groups (so-called phenolic aralkyl resins' family resins).

In formula (1), _X1 represents a tetravalent aromatic ring-containing group, _Y1 represents a divalent aromatic ring-containing group, and a portion of the hydrogen atom in _X1 and _Y1 may also be substituted by a straight-chain or branched hydrocarbon with 1 to 20 carbon atoms. Additionally, _V1 is the substituent represented by the general formula (2) below. Furthermore, l represents a number from 0 to 20, and the average value of l is preferably 0.2 to 4.0. _Q1 is a hydrogen atom or a straight-chain or branched hydrocarbon with 1 to 20 carbon atoms.

In formula (2), _R1 represents a hydrogen atom or a methyl group. L represents a substituent represented by the general formula (3) below. * indicates the site of bonding with the oxygen atom (O) in formula (1).

In formula (3), M represents a divalent or trivalent residual group derived from a dicarboxylic acid, tricarboxylic acid, or an anhydride thereof, and p is 1 or 2. * indicates the site of bonding with the oxygen atom (O) in formula (2).

For example, the alkali-soluble resin represented by general formula (1) can be an alkali-soluble resin derived from biphenyl aralkyl resin represented by general formula (4) below. Furthermore, X ₂ , Y ₂ , V ₂ and Q ₂ in formula (4) correspond to X ₁ , Y ₁ , V ₁ and Q ₁ in formula (1), respectively.

In formula (4), _X2 is a tetravalent substituent represented by the following general formula (5) derived from biphenol compounds, and _Y2 is a divalent substituent represented by the following general formula (6). In the following general formulas (5) and (6), a portion of the hydrogen atom may also be substituted with a straight-chain or branched hydrocarbon 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 value of m as an average value is preferably 0.2 to 4.0. _Q2 is a hydrogen atom or a straight-chain or branched hydrocarbon having 1 to 20 carbon atoms.

In the above general formula (4), when _X2 is a structure bonded to two _Y2 , as shown in the following general formula (5), the two bonds can be located on either benzene ring, or each of the two benzene rings can have a bond, forming a configuration bonded to _Y2 . Furthermore, in one embodiment of the present invention, a configuration in which two bonds are bonded to one benzene ring is representatively described.

In equation (5), * indicates the location bonded to the oxygen atom (O), _Y2 , or _Q2 in equation (4). Furthermore, it is preferable that the upper and lower bonding locations in equation (5) (located at positions 4 and 4') are the locations bonded to the oxygen atom (O) in equation (4), and the left and right bonding locations (other bonding locations) are the locations bonded to _Y2 or _Q2 in equation (4), but this is not a limitation.

In equation (6), * indicates the part that is bonded to X ₂ in equation (4).

In formula (2), _R1 represents a hydrogen atom or a methyl group, L represents a substituent represented by the general formula (3) below, and * represents the site bonded to the oxygen atom (O) in formula (4).

In formula (3), M represents a divalent or trivalent residual group derived from a dicarboxylic acid, tricarboxylic acid, or an anhydride thereof, p is 1 or 2, and * indicates the site of bonding with the oxygen atom (O) in formula (2).

The alkali-soluble resin represented by general formula (1) of one embodiment of the present invention simultaneously possesses polymerizable unsaturated groups and carboxyl groups. Therefore, photosensitive resin compositions containing this alkali-soluble resin exhibit excellent photocuring properties, good developing properties, and patterning characteristics. This can be described as an effective technique, particularly for applications requiring heat resistance, when preparing said photosensitive resin composition into cured products.

[Method for manufacturing photosensitive resin components]

(Method for manufacturing alkaline-soluble resins)

First, the method for manufacturing the alkali-soluble resin represented by general formula (1) will be explained in detail, taking the alkali-soluble resin represented by general formula (4) as an example.

The alkali-soluble resin represented by general formula (4) is the following alkali-soluble resin (hereinafter referred to as biphenol aralkyl alkali-soluble resin), wherein X ₂ is a tetravalent substituent represented by general formula (5) derived from biphenol compounds, Y ₂ is a divalent substituent represented by general formula (6), Q ₂ is a hydrogen atom, V ₂ is a substituent represented by general formula (2), and has polymerizable double bonds and carboxyl groups within a molecule.

The alkali-soluble resin represented by general formula (4) is obtained as follows: A cyclic ether compound such as epichlorohydrin is reacted with a biphenol aralkyl resin in the form of a biphenol compound bonded to an aromatic ring to obtain an epoxy compound; then, a carboxylic acid compound containing an unsaturated group, such as (meth)acrylic acid, is reacted with the obtained epoxy compound to obtain a polyol compound with a polymerizable unsaturated group; further, a dicarboxylic acid, tricarboxylic acid, or its anhydride is reacted with the obtained polyol compound with a polymerizable unsaturated group.

Specifically, the alkali-soluble resin represented by general formula (4) can be obtained by adding a polycarboxylic acid or its anhydride to a polyol compound containing a polymerizable unsaturated group, obtained by reacting an epoxy compound having a biphenyl skeleton with (meth)acrylic acid. The epoxy compound having a biphenyl skeleton is formed by replacing the hydrogen atom of the phenolic hydroxyl group of a biphenyl aralkyl resin represented by general formula (7) with a glycidyl group and having two or more glycidyl ether groups, and is represented by general formula (8). Furthermore, the method for manufacturing this epoxy compound having a biphenyl skeleton can be found, for example, in International Publication No. 2011/74517. Moreover, in the case of manufacturing the resin represented by general formula (7), it is usually obtained as a mixture of molecules with different numbers of n.

In equation (7), n represents a number from 0 to 20, and the optimal value of n for the average is 0.2 to 4.0.

In equation (8), o represents a number from 0 to 20, and the preferred value of o for the average value is 0.2 to 4.0. W represents the glycidyl group.

The polymerization method for biphenyl aralkyl resins can refer to the general manufacturing methods for phenol resins and phenol aralkyl resins.

Specifically, the epoxy compound represented by general formula (8) can be obtained by reacting a biphenol aralkyl resin represented by general formula (7) with epichlorohydrin. A method for manufacturing a multi-hydroxyl resin as a raw material for epoxy resins will be explained.

As a first stage, multi-functional hydroxyl resins can be obtained by condensing biphenols with crosslinking agents in the absence of a catalyst or in the presence of an acidic catalyst.

The examples of biphenols mentioned above include 4,4'-dihydroxybiphenyl, etc.

In addition, examples of the aforementioned crosslinking agents include 4,4'-bis(hydroxymethyl)biphenyl, 4,4'-bis(chloromethyl)biphenyl, 4,4'-bis(bromomethyl)biphenyl, 4,4'-bis(methoxymethyl)biphenyl, and 4,4'-bis(ethoxymethyl)biphenyl. Among the aforementioned crosslinking agents, 4,4'-bis(chloromethyl)biphenyl, 4,4'-bis(hydroxymethyl)biphenyl, and 4,4'-bis(methoxymethyl)biphenyl are preferred.

The aforementioned acidic catalyst can be appropriately selected from well-known inorganic and organic acids, including 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, solid acids such as activated clay and zeolite, etc.

As a second stage, the hydrogen atom of the phenolic hydroxyl group in the biphenyl aralkyl resin represented by general formula (7) can be replaced with a glycidyl group to obtain an epoxide compound with a biphenyl skeleton represented by general formula (8) having two or more glycidyl ether groups. Its preparation method can be the same as a conventional hydroxyl group epoxidation reaction, for example, by dissolving the biphenyl aralkyl resin in excess epichlorohydrin and reacting it at 20°C to 150°C for 1 to 10 hours in the presence of an alkaline metal hydroxide such as sodium hydroxide.

Next, the reaction of this epoxy compound with (meth)acrylic acid can be carried out using known methods. For example, 1 mole of (meth)acrylic acid is used relative to 1 mole of epoxy groups. To ensure that the (meth)acrylic acid reacts with all epoxy groups, it is preferable to add a slight excess of (meth)acrylic acid relative to the equimolar amounts of epoxy and carboxyl groups. Alternatively, a resin obtained by partially or completely replacing (meth)acrylic acid with carboxyl-containing (meth)acrylates and reacting it can also be used. Carboxyl-containing (meth)acrylates are compounds having one carboxyl group and one or more (meth)acrylate groups within their molecules. Examples of carboxyl-containing (meth)acrylates include 2-acrylic acid, 2-acrylic acid, 2-acrylic acid, 2-hexahydrophthalic acid, 2-acrylic acid, 2-acrylic acid, 2-acrylic acid, and 2-methacrylic acid.

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

In formula (9), q represents a number from 0 to 20, and the value of q as the average value is preferably 0.2 to 4.0. _W1 is a substituent with a polymerizable unsaturated group in the molecule, as represented by the following general formula (10).

In formula (10), _R2 represents a hydrogen atom or a methyl group. * indicates the site of bonding with the oxygen atom (O) in formula (9).

There are no particular restrictions on the solvents, catalysts, and other reaction conditions used in this process. For example, the solvent preferably does not contain hydroxyl groups and has a boiling point higher than the reaction temperature. Examples of such solvents include: solvent-based solvents containing ethyl solvent acetate and butyl solvent acetate; high-boiling-point ether or ester-based solvents containing diethylene glycol dimethyl ether, ethyl carbitol acetate, butyl carbitol acetate, and propylene glycol monomethyl ether acetate; and ketone-based solvents containing cyclohexanone and diisobutyl ketone. Examples of catalysts include: ammonium salts containing tetraethylammonium bromide and triethylbenzylammonium chloride; and phosphine-based catalysts containing triphenylphosphine and tris(2,6-dimethoxyphenyl)phosphine, among other known catalysts.

The base-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, a tricarboxylic acid, or an anhydride of such an acid.

Examples of the aforementioned dicarboxylic or tricarboxylic acids, or their monohydric anhydrides, include saturated chain dicarboxylic or tricarboxylic acids, saturated cyclic dicarboxylic or tricarboxylic acids, unsaturated dicarboxylic or tricarboxylic acids, aromatic dicarboxylic or tricarboxylic acids, or their monohydric anhydrides. Furthermore, the hydrocarbon residues (structures other than the carboxyl group) of these monohydric anhydrides may also be substituted with alkyl, cycloalkyl, aromatic, or other substituents.

Examples of monoanhydrides of saturated chain dicarboxylic or tricarboxylic acids include monoanhydrides of succinic acid, acetylsuccinic acid, adipic acid, azelaic acid, malic acid, malonic acid, glutaric acid, citric acid, tartaric acid, oxoglutaric acid, pimelic acid, sebacic acid, octanoic acid, and diglycolic acid.

In addition, examples of monohydric anhydrides of saturated cyclic dicarboxylic or tricarboxylic acids include monohydric anhydrides of hexahydrophthalic acid, cyclobutanedicarboxylic acid, cyclopentanedicarboxylic acid, norbornanedicarboxylic acid, and hexahydrotriphenylcarboxylic acid.

In addition, examples of monohydric anhydrides of unsaturated dicarboxylic or tricarboxylic acids include monohydric anhydrides of maleic acid, itaconic acid, tetrahydrophthalic acid, methylmethylenetetrahydrophthalic acid, chlorendic acid, etc.

Furthermore, examples of the monohydric anhydrides of aromatic dicarboxylic or tricarboxylic acids include monohydric anhydrides of phthalic acid, trimellitic acid, etc.

The anhydrides of the dicarboxylic or tricarboxylic acids are preferably those of succinic acid, hexahydrophthalic acid, hexahydrotriphenylamine, maleic acid, itaconic acid, tetrahydrophthalic acid, phthalic acid, and trimellitic acid; more preferably, they are anhydrides of succinic acid, hexahydrotriphenylamine, maleic acid, itaconic acid, tetrahydrophthalic acid, phthalic acid, and trimellitic acid. Furthermore, the anhydrides of the dicarboxylic or tricarboxylic acids may be used alone or in combination with two or more.

The reaction temperature for synthesizing the base-soluble resin represented by general formula (4) by reacting the hydroxyl group of the compound represented by general formula (10) with di or tricarboxylic acids or their monohydric anhydrides is preferably 20–120 °C, and more preferably 40–90 °C. The molar ratio of the monohydric anhydride during the synthesis of the compound represented by general formula (4) can be arbitrarily changed to adjust the acid value of the base-soluble resin represented by general formula (4).

Thus, the alkali-soluble resin represented by general formula (4) can be obtained.

Furthermore, the alkali-soluble resin represented by general formula (1) is not limited to the alkali-soluble resin obtained by the above method. For example, known naphthoquinone aralkyl resins or biphenyl aralkyl resins can be used instead of the biphenol aralkyl resin represented by general formula (7). Alternatively, known biphenol aralkyl resins obtained using aromatic compounds other than biphenyl compounds (such as crosslinking agents used in the synthesis of the naphthoquinone aralkyl resins described later) as crosslinking agents can be used instead of the biphenol aralkyl resin represented by general formula (7).

When using aralkyl naphthol resins, various naphthols such as 1,5-naphthol, 1,6-naphthol, 1,7-naphthol, 1,8-naphthol, 2,6-naphthol, and 2,7-naphthol can be used instead of the biphenols.

As a crosslinking agent in the synthesis of naphthyldiol aralkyl resins, the following halogenated alkyl compounds can be used: 1,4-bis(chloromethyl)benzene, 1,4-bis(chloroethyl)benzene, 4,4'-bis(chloromethyl)biphenyl, 4,4'-bis(bromomethyl)biphenyl, 4,4'-bis(chloromethylbiphenyl) ether, etc.; alcohols such as p-xylene glycol, p-di(hydroxyethyl)benzene, 4,4'-bis(hydroxymethyl)biphenyl, 2,6-bis(hydroxymethyl)naphthalene, 2,2'-bis(hydroxymethyl)diphenyl ether, etc.; dialkyl ethers of the aforementioned alcohols such as 4,4'-bis(methoxymethyl)biphenyl, 4,4'-bis(ethoxymethyl)biphenyl, p-xylene glycol dimethyl ether, etc.; and divinyl compounds such as divinylbenzene, divinylbiphenyl, etc.

Furthermore, when using known biphenyl aralkyl resins obtained by using aromatic compounds other than biphenyl compounds as crosslinking agents, an alkali-soluble resin obtained by synthesis using the same method as that used for biphenyl aralkyl resins represented by general formula (7) can be used, in addition to using the crosslinking agent (other than biphenyl compounds). Additionally, when using naphthol aralkyl resins or biphenyl aralkyl resins, the alkali-soluble resin of this invention can also be obtained by the same method.

(Method for manufacturing photosensitive resin components)

Next, a method for manufacturing a photosensitive resin composition according to an embodiment of the present invention will be described. In addition to comprising (i) the alkali-soluble resin represented by general formula (1), the photosensitive resin composition of the present invention also comprises (ii) a photopolymerizable monomer having at least one polymerizable unsaturated group and (iii) a photopolymerization initiator. The components will be described below.

The photosensitive resin composition comprises an alkali-soluble resin represented by the general formula (1) as (i) an alkali-soluble resin. The content of component (i) is preferably 30% by mass and 80% by mass in the solid components of the photosensitive resin composition (excluding the solvent; the solid components include monomers that become solid components after curing)).

Examples of photopolymerizable monomers having at least one polymerizable unsaturated group as component (ii) include monomers having hydroxyl groups such as 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, and 2-ethylhexyl methacrylate; and (meth)acrylates 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, trihydroxymethylpropane tri(meth)acrylate, trihydroxymethylethane 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. Where it is necessary to form a cross-linked structure between molecules of an alkali-soluble resin, it is preferable to use a photopolymerizable monomer having two or more polymerizable unsaturated groups, and more preferably a photopolymerizable monomer having three or more polymerizable unsaturated groups. Furthermore, these compounds may be used alone or in combination of two or more.

The mixing ratio of component (ii) to the alkaline-soluble resin [(i) component] [(i)/(ii)] is preferably 20/80 to 90/10, more preferably 40/60 to 80/20. Here, if the proportion of alkaline-soluble resin is sufficiently high, the cured product after the photocuring reaction will become sufficiently hard. In addition, since the acid value of the coating film becomes sufficiently high and it dissolves sufficiently in the alkaline developer, the edges of the pattern in the unexposed areas are less likely to wobble and become easier to become clear. Conversely, by ensuring that the proportion of alkaline-soluble resin is not too high, the proportion of photoreactive functional groups in the resin is sufficiently increased, and the cross-linked structure can be fully formed by the photocuring reaction. Furthermore, the resin component has a low acid value, thus easily suppressing its solubility relative to alkaline developing solutions within a specified range. It also facilitates the formation of patterns with the target line width in the exposed areas, reducing the likelihood of pattern defects.

Examples of photopolymerization initiators as components (iii) include acetophenones such as acetophenone, 2,2-diethoxyacetophenone, p-dimethylacetophenone, p-dimethylaminoacetophenone, dichloroacetophenone, trichloroacetophenone, and p-tert-butylacetophenone; phenylalkyl ketones such as 1-hydroxycyclohexylphenyl ketone; benzophenones such as 2-chlorobenzophenone and p,p'-bis(dimethylamino)benzophenone; benzoyl ethers such as benzoin, benzoin methyl ether, benzoin isopropyl ether, and benzoin isobutyl ether; and benzoin ethers such as 2-(n-chlorophenyl)-4,5-phenylbiimidazole, 2-(n-chlorophenyl)-4,5-di(m-methoxyphenyl)biimidazole, and 2-(n-fluorophenyl)-4,5-diphenylbiimidazole. Biimidazole compounds such as 2-(orthomethoxyphenyl)-4,5-diphenylbiimidazole and 2,4,5-triarylbiimidazole; halogenated methylthiazole compounds such as 2-trichloromethyl-5-styryl-1,3,4-oxadiazole, 2-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 halogenated triazine compounds, including 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; 1,2-octanedione, 1-[4-(phenylthio)phenyl]-,2-(O-benzoyl oxime), and 1-(4-phenylthiophenyl)butane-1,2-dione. -2-oxime-O-benzoate, 1-(4-methylphenyl)butane-1,2-dione-2-oxime-O-acetate, 1-(4-methylphenyl)butane-1-one oxime-O-acetate, and other O-acetylated oxime compounds; benzodiazepine dimethyl acetone, thiatonone, 2-chlorothiatonone, 2,4-diethylthiatonone, 2-methylthiatonone, 2 - Sulfur compounds such as isopropylthiotonone; anthraquinones such as 2-ethylanthraquinone, octamethylanthraquinone, 1,2-benzanthraquinone, and 2,3-diphenylanthraquinone; organic peroxides such as azobisisobutyronitrile, benzoyl peroxide, and cumene peroxide; thiols such as 2-phenylbenzimidazole, 2-phenylbenzoxazole, and 2-phenylbenzothiazole; and tertiary amines such as triethanolamine and triethylamine. Furthermore, these photopolymerization initiators can be used alone or in combination.

Relative to 100 parts by mass of the combined amount of (i) alkaline-soluble resin and (ii) photopolymerizable monomer, the content of the photopolymerization initiator as component (iii) is preferably 0.1 to 10 parts by mass, more preferably 2 to 5 parts by mass. Here, if the amount of photopolymerization initiator added is 0.1 parts by mass or more, the sensitivity is sufficiently high; if the amount of photopolymerization initiator added is 10 parts by mass or less, it is less likely to result in unclear tapered shapes (film thickness direction shape in the development pattern cross-section) and halos with a downward sloping appearance. Furthermore, the possibility of generating decomposition gases when exposed to high temperatures in subsequent steps is also reduced.

Additionally, the photosensitive resin composition of one embodiment of the present invention may also include (iv) the epoxy compound.

(iv) The epoxy compounds may be used without particular restriction as commercially available known compounds such as epoxy resins. Examples of epoxy resins include bisphenol A type epoxy compounds, bisphenol F type epoxy compounds, bisphenol S type epoxy resins, biphenyl type epoxy resins, bisphenol fluorene type epoxy compounds, phenolic varnish type epoxy compounds, cresol phenolic varnish type epoxy compounds, glycidyl ethers of polyols, glycidyl esters of polycarboxylic acids, polymers containing glycidyl (meth)acrylate as a unit, and 3,4-epoxycyclohexanecarboxylic acid [(3,4- Alicyclic epoxides represented by cyclohexyl(epoxy)methyl esters, 1,2-epoxy-4-(2-oxocyclopropyl)cyclohexane adducts of 2,2-bis(hydroxymethyl)-1-butanol (e.g., EHPE3150 from Daicel), phenyl glycidyl ether, p-butylphenol glycidyl ether, triglyceride isocyanate, diglyceride isocyanate, epoxidized polybutadiene (e.g., NISSO-PB.JP-100 from Nippon Soda Co., Ltd.), and epoxides with a silicone backbone. These components are preferably compounds with an epoxy equivalent of 100 g/eq to 300 g/eq and a number average molecular weight of 100 to 5000. (iv) The component may be a single compound or two or more compounds. Where there is a need to increase the crosslinking density of the alkali-soluble resin, a compound having at least two epoxy groups is preferred.

Compared to the total of 100 parts by mass of components (i) and (ii), the content of the epoxy compound in (iv) is preferably 10 to 40 parts by mass. Here, one purpose of adding the epoxy compound is sometimes to reduce the amount of carboxyl groups remaining after patterning to improve the reliability of the hardened film. By setting the amount of epoxy compound added to 10 parts by mass or more, the moisture resistance reliability when used as an insulating film can be further improved. Furthermore, by setting the amount of epoxy compound to 40 parts by mass or less, the amount of photosensitive groups in the resin component of the photosensitive resin composition can be sufficiently increased, resulting in sufficient sensitivity for patterning.

The photosensitive resin composition of one embodiment of the present invention may also include a dispersed phase as component (v).

As a dispersed phase for component (v), any known dispersed phase used in photosensitive resin compositions may be used without particular restriction, provided that it is dispersed with an average particle size of 1 to 1000 nm (measured by laser diffraction or dynamic light scattering). Examples of dispersed phases include organic pigments such as azo pigments, condensed azo pigments, azomethyl pigments, phthalocyanine pigments, quinacridone pigments, isoindolineone pigments, isoindoline pigments, dioxazine pigments, threne pigments, perylene pigments, perinone pigments, quinoline phthalone pigments, diketopyrrolopyrrole pigments, and indigo sulfide pigments; titanium oxide pigments. Inorganic pigments such as polymers and composite oxide pigments; pigments such as carbon black pigments (actually colorants that are insoluble in the medium); organic fillers such as acrylic polymer particles and carbamate 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 nanoparticles of metals or metal oxides.

These (v) dispersions can be used alone or in combination, depending on the function of the target photosensitive resin composition. Examples of light-shielding anti-corrosion agents used in the manufacture of black matrices for color filters include carbon black, titanium black, and black organic pigments. Examples of coloring anti-corrosion agents used in the manufacture of pixels for color filters include red, orange, yellow, green, blue, and purple organic pigments. Examples of solder resists used in the manufacture of insulating films for printed circuit boards include organic pigments, inorganic pigments, and inorganic fillers. Examples of decorative anti-corrosion agents 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 corrosion inhibitors with high hardness, high refractive index, and high durability include transparent fillers such as silicon dioxide and titanium dioxide. These (v) dispersions can be appropriately selected for use.

Furthermore, examples of (v) dispersed phases being light-blocking materials include black organic pigments, mixed-color organic pigments, and black inorganic pigments. In this case, the (v) dispersed phase (light-blocking material) varies depending on the application, but is preferably one with excellent insulation, heat resistance, lightfastness, and solvent resistance. Examples of black organic pigments as light-blocking materials include perylene black, aniline black, cyanine black, and lactam black. Examples of mixed-color organic pigments as light-blocking materials include pigments prepared by mixing two or more pigments selected from red, blue, green, purple, yellow, cyanine, and magenta and then simulating blackening. Examples of black inorganic pigments as light-blocking materials include carbon black, chromium oxide, iron oxide, and titanium black. One or more of these (v) dispersed phases may be used.

Furthermore, examples of organic pigments that can be used as ingredient (v) include, but are not limited to, pigments with the following designations in the Color Index.

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 in ratios of 15, 15:1, 15:2, 15:3, 15:4, 15:6, 16, 60, and 80, etc.

Pigment violet (19, 23, 37, etc.)

Furthermore, as other dispersions, known rubber components can be added to improve impact resistance and adhesion to the plated metal during processing. To ensure development, the rubber component is preferably a carboxyl-containing crosslinked elastic polymer. Examples of rubber components include carboxyl-containing crosslinked acrylic rubber, carboxyl-containing crosslinked acrylonitrile butadiene rubber (NBR), and carboxyl-containing crosslinked methyl methacrylate butadiene styrene (MBS). When using a rubber component, it is preferable to add 3 to 10 parts by weight of a component with an average particle size of 0.1 μm or less, relative to 100 parts by weight of the resin component.

(v) The dispersant is preferably prepared by pre-dispersing the dispersant in a solvent to form a dispersion before being formulated as a photosensitive resin composition. In this case, one of the solvents exemplified as solvents for dissolving the photosensitive resin composition of the present invention may be used alone, or two or more may be used in combination.

The proportion of the dispersed phase forming the dispersion can be set to 1-95% by mass relative to the total solid content of the photosensitive resin composition of the present invention. Furthermore, the solid content refers to the components in the composition other than the solvent. The solid content also includes component (ii) which becomes a solid component after photocuring. The wide range of 1-95% by mass of the dispersed phase is due to the existence of dispersed phases with low specific gravity, such as those made of organic matter like acrylic resin particles or rubber particles, and dispersed phases with high specific gravity, such as those made of metal particles or metal oxide particles. Additionally, when the dispersed phase is added for coloring purposes, 5-80% by mass is preferred. By including more than 5% by mass in the solid content, the desired coloring is achieved, and the desired functions of the dispersed phase, such as opacity, are easily imparted. By setting the content of the photosensitive resin, which is originally used as a binder, to below 80% by mass in the solid component, the amount of the photosensitive resin can be sufficiently increased, ensuring development properties and film-forming ability. Therefore, in the case of colorants (including light-blocking materials), the content of component (v) in the solid component is preferably 10-70% by mass, more preferably 20-60% by mass.

In addition, to ensure stable dispersion of the dispersed phase, the dispersion may contain known dispersants such as polymeric dispersants. These may include known compounds used in pigment dispersion (commercially available under names such as dispersant, dispersing wetting agent, and dispersing accelerator).

Examples of dispersants include cationic polymeric dispersants, anionic polymeric dispersants, nonionic polymeric dispersants, and pigment derivative-type dispersants (dispersing aids). In particular, the dispersant is preferably a cationic polymeric dispersant having cationic functional groups such as imidazole, pyrrole, pyridinium, primary amine, secondary amine, or tertiary amine groups as adsorption sites for dispersed substances such as pigments, and having an amine value in the range of 1 mg KOH/g to 100 mg KOH/g and a number average molecular weight in the range of 1,000 to 100,000. The amount of this dispersant prepared relative to the dispersed substance is preferably 1% to 35% by mass, more preferably 2% to 25% by mass. Furthermore, high-viscosity substances like resins generally have a stabilizing effect on dispersion; substances that do not promote dispersion are not considered dispersants. However, their use for the purpose of stabilizing dispersion is not restricted.

The dispersion obtained in the manner described above can be mixed with component (i) (the remaining component (i) if it is co-dispersed during the preparation of the dispersion), component (ii), component (iii), and any additional component (iv), and solvent can be added as needed to achieve a suitable solution viscosity, thereby producing a photosensitive resin composition containing the dispersed phase.

Additionally, the photosensitive resin composition of one embodiment of the present invention may also include a solvent.

Examples of solvents 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; and solvents such as methyl solvents, ethyl solvents, carbitol, methyl carbitol, ethyl carbitol, butyl carbitol, and propylene glycol. Glycol ethers such as monomethyl ether (MME), propylene glycol monoethyl ether (ME), dipropylene glycol monomethyl ether (ME), triethylene glycol monomethyl ether (ME), and triethylene glycol monoethyl ether (ME); acetate esters such as ethyl acetate, butyl acetate, solvent acetate, ethyl solvent acetate, butyl solvent acetate, carbitol acetate, ethyl carbitol acetate, butyl carbitol acetate, propylene glycol monomethyl ether acetate, and propylene glycol monoethyl ether acetate. By dissolving and mixing these ethers individually or in combination (two or more), a homogeneous solution can be prepared.

Furthermore, the photosensitive resin composition of this invention can be formulated with additives such as hardeners, hardening accelerators, thermal polymerization inhibitors, antioxidants, chain transfer agents, plasticizers, leveling agents, defoamers, coupling agents, surfactants, and UV absorbers as needed. To control the properties of the cured product, resins such as vinyl resins, polyester resins, polyamide resins, polyimide resins or their precursors, polybenzoxazole resins or their precursors, polyurethane resins, polyether resins, and melamine resins can also be added.

Hardeners can be, for example, compounds known to be suitable as hardeners for epoxy compounds. Examples of hardeners include amine compounds, polycarboxylic acid compounds, amino resins, dicyandiamine, Lewis acid complexes, phenolic resins, etc.

As curing accelerators, well-known compounds commonly used as curing accelerators, curing catalysts, and potential curing agents in epoxy compounds can be utilized. Examples of curing accelerators include tertiary amines, tertiary ammonium salts, tertiary phosphine salts, tertiary phosphonium salts, borate esters, Lewis acids, organometallic compounds, imidazoles, and diazabicyclic compounds. Examples of thermal polymerization inhibitors and antioxidants include hydroquinone, hydroquinone monomethyl ether, pyrogallol, tertiary butylcatechol, phenanthrene, hindered phenolic antioxidants, and phosphorus-based thermal stabilizers. Examples of chain transfer agents include thiol compounds, halogen compounds, quinone compounds, and α-methylstyrene dimers. Examples of plasticizers include dibutyl phthalate, dioctyl phthalate, and tricresyl phosphate. Examples of defoamers and leveling agents include silicone-based, fluorinated, and acrylic compounds. Examples of coupling agents include vinyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-(glycidyloxy)propyltrimethoxysilane, 3-isocyanopropyltriethoxysilane, 3-aminopropyltriethoxysilane, 3-(phenylamino)propyltrimethoxysilane, and 3-ureopropyltriethoxysilane. Examples of surfactants include fluorinated surfactants and silicone-based surfactants. Examples of ultraviolet absorbers include benzotriazole compounds, benzophenone compounds, and triazine compounds.

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

Thus, the photosensitive resin composition of this invention can be obtained.

Photosensitive resin compositions comprising an alkaline-soluble resin represented by general formula (1), manufactured as described above, are exemplified by solder resists, plating resists, and etching resists used in the manufacture of circuit boards. They are hardened films formed using photolithography, exhibiting excellent heat resistance and possessing excellent dimensional accuracy and pattern cross-sectional shape, such as color filters or light-shielding films for liquid crystal displays, organic electroluminescent (EL) displays, microluminescent diode (μLED) displays, and image sensors.

Specific examples are given of each step in a film-forming method for a coating (cured material) obtained by applying and drying a photosensitive resin composition.

Furthermore, the coating (cured material) of this invention is obtained, for example, by applying a solution of a photosensitive resin composition to a substrate, drying it, and then curing it by irradiation with light (including ultraviolet light, radiation, etc.). By using a photomask or similar device to create areas that are exposed to light and areas that are not, only the light-exposed areas are cured, and the other areas are dissolved using an alkaline solution, thereby obtaining a coating with the desired pattern.

Specific examples of the film-forming methods involving the coating and drying of photosensitive resin compositions include the application of the photosensitive resin composition onto the substrate using any of the known methods such as solution impregnation, spraying, using a roller coater, a land coater, a slit coater, or a rotary coater. After coating to the desired thickness using these methods, the solvent is removed (pre-baking) to form the film. Pre-baking is performed using heating in an oven, a heating plate, vacuum drying, or a combination thereof. The heating temperature and time for pre-baking can be appropriately selected depending on the solvent used, for example, at 80°C to 120°C for 1 to 10 minutes.

The radiation used in the exposure can be, for example, visible light, ultraviolet light, far-ultraviolet light, electron beams, X-rays, etc., with a wavelength range preferably between 250 nm and 450 nm. Examples of suitable developing solutions for this alkaline developing process include aqueous solutions of sodium carbonate, potassium carbonate, potassium hydroxide, diethanolamine, tetramethylammonium hydroxide, etc. These developing solutions can be appropriately selected based on the characteristics of the resin layer, and the addition of surfactants as needed is also effective. The preferred developing temperature is 20°C to 35°C, and commercially available developing machines or ultrasonic cleaners can be used to precisely form fine images. Furthermore, water rinsing is typically performed after alkaline developing. As a developing method, it can be applied to spray developing, mist developing, dip developing, and puddle developing, among others.

After development as described above, a heat treatment (post-baking) is performed at 180°C to 250°C for 20 to 100 minutes. This post-baking is performed to improve the adhesion between the patterned coating and the substrate. It is performed similarly to pre-baking by heating using an oven or heating plate. The patterned coating of this invention is formed through the above-described steps using photolithography. Then, polymerization or curing (sometimes both are collectively referred to as curing) is completed by heat to create a cured film pattern. The preferred curing temperature at this stage is 160°C to 250°C.

Compared to previous photosensitive resin compositions, the photosensitive resin composition of this invention has a higher number of unsaturated polymerizable groups, thus improving photocurability. This allows for increased crosslinking density after curing without increasing the amount of photopolymerization initiator. Specifically, in the case of a thick film irradiated with ultraviolet light or an electron beam, the cured portion hardens to the bottom, eliminating the solubility difference of the alkaline developer between the exposed and unexposed areas. This results in improved pattern size stability, development margin, and pattern adhesion, enabling high-resolution pattern formation. Furthermore, in the case of a thin film, the increased sensitivity significantly improves the amount of residual film in the exposed area and suppresses peeling during development.

The photosensitive composition of this invention is extremely useful for use in the manufacture of solder resists, plating resists, etching resists, or insulating films for multilayering wiring substrates carrying semiconductor components, various insulating films for semiconductor devices, gate insulating films for semiconductors, and photosensitive adhesives (especially adhesives that require heat treatment for bonding performance after patterning using photolithography).

[Implementation Example]

The embodiments and comparative examples of this invention will be described in detail below, but this invention is not limited to these. Furthermore, in this invention, when the first decimal place of the content of each component is 0, the description below the decimal point is sometimes omitted.

First, examples of synthesized alkali-soluble resins containing polymerizable unsaturated groups, represented by general formula (1) as component (i), will be explained. However, unless otherwise explained, the resins in these synthetic examples will be evaluated as follows.

[Solid content concentration]

The following formula is used to calculate the mass of the resin solution and photosensitive resin composition (1g) obtained in Synthesis Example 1, Synthesis Example 2 and Comparative Synthesis Example after immersing them in a glass filter [mass: _W0 (g)] and weighing [ _W1 (g)] and heating at 160°C for 2 hours [ _W2 (g)].

Solid content concentration (mass %) = 100 × ( _W2 - _W0 ) / ( _W1 - _W0 )

[Acid Value]

Regarding acid value, the resin solution was dissolved in tetrahydrofuran, and titrated using a potentiometric titration apparatus COM-1600 (manufactured by Hiranuma Sangyo Co., Ltd.) with a 1/10 N-KOH aqueous solution. The amount of KOH required per 1g of solid component was taken as the acid value.

[Molecular weight]

Molecular weight was determined by gel osmosis chromatography (GPC) (TOSOH HLC-8320 GPC, column: two TSKgelSuper H2000 columns + one TSKgelSuper H3000 column + one TSKgelSuper H4000 column + one TSKgelSuper H5000 column (all TOSOH), solvent: tetrahydrofuran, temperature 40℃, flow rate 0.6 ml/min). The value calculated using standard polystyrene (TOSOH PS-Oligomer Kit) conversion was used as the weight-average molecular weight (Mw).

Furthermore, the abbreviations recorded in Synthetic Examples 1-3 and the Comparative Synthetic Examples are as follows.

BPAEA: An epoxy compound (epoxide equivalent 199 g/eq, W in general formula (8) is a glycidyl group) obtained by reacting epichlorohydrin with the product of 4,4'-biphenyl and 4,4'-dichloromethylbiphenyl (biphenyl aralkyl resin), and then reacting acrylic acid with it to obtain a compound (equissential reaction product of epoxy and carboxyl groups).

BNAEA: An epoxy compound (epoxide equivalent 166) obtained by reacting epichlorohydrin with the product of 1,6-dihydroxynaphthalene and p-xylene glycol dimethyl ether (naphthoquinone aralkyl resin), and subsequently by reacting acrylic acid with it to obtain a compound (equal stoichiometric reaction product of epoxy and carboxyl groups).

BPDA: 3,3',4,4'-Biphenyltetracarboxylic acid dianhydride

THPA: 1,2,3,6-Tetrahydrophthalic anhydride

SA: Succinic anhydride

TEAB: Tetraethylammonium bromide

PGMEA: Propylene Glycol Monomethyl Ether Acetate

The following synthetic examples 1 and 2 are examples of synthesizing alkali-soluble resins of general formula (1) that contain carboxyl groups and polymerizable unsaturated groups within a single molecule. The comparative synthetic example is an alkali-soluble resin containing polymerizable unsaturated groups, having a backbone different from that of the alkali-soluble resin represented by general formula (1), and is an epoxy acrylate adduct of a bisphenol A type epoxy compound. Furthermore, the following synthetic example 3 is an example of synthesizing an alkali-soluble resin of general formula (1) that contains carboxyl groups and polymerizable unsaturated groups within a single molecule.

Synthesis example 1

(Synthesis of alkaline soluble resin (i)-1 represented by general formula (1))

A 50% PGMEA solution of BPAEA (419.6 g), THPA (88.3 g), TEAB (1.63 g), and PGMEA (29.2 g) were added to a 1000 ml four-necked flask equipped with a reflux cooler. The mixture was stirred at 120°C–125°C for 6 hours to obtain an alkali-soluble resin (i)-1. The obtained resin had a solid content of 56.2 wt%, an acid value (converted from solid content) of 113.6 mg KOH/g, and a molecular weight (Mw) of 3410 as determined by GPC analysis.

[Synthesis example 2]

(Synthesis of alkaline soluble resin (i)-2 represented by general formula (1))

A 50% PGMEA solution of BPAEA (419.6 g), SA (58.1 g), TEAB (1.63 g), and PGMEA (5.2 g) were added to a 1000 ml four-necked flask equipped with a reflux cooler. The mixture was stirred at 120°C–125°C for 6 hours to obtain an alkali-soluble resin (i)-2. The obtained resin had a solid content concentration of 56.1 wt%, an acid value (converted from solid content) of 125.7 mg KOH/g, and a molecular weight (Mw) of 3220 as determined by GPC analysis.

[Comparative synthesis example]

(Synthesis of alkaline-soluble resin (i)-3)

A 50% PGMEA solution (442.0 g), BPDA (20.6 g), THPA (24.3 g), TEAB (0.84 g), and PGMEA (12.0 g) of the reaction product of bisphenol A type epoxy compound (epoxy equivalent 480 g/eq) and acrylic acid were added to a 1000 ml four-necked flask equipped with a reflux cooler. The mixture was stirred at 120–125 °C for 6 hours to obtain an alkali-soluble resin (i)-3. The solid content of the obtained resin was 56.1 wt%, the acid value (converted from solid content) was 62.7 mg KOH/g, and the molecular weight (Mw) analyzed by GPC was 9000.

[Synthesis example 3]

(Synthesis of alkaline soluble resin (i)-4 represented by general formula (1))

A 50% PGMEA solution of BNAEA (368.5 g), THPA (88.3 g), TEAB (1.63 g), and PGMEA (54.7 g) were placed in a 1000 ml four-necked flask equipped with a reflux cooler and stirred at 120-125 °C for 6 hours to obtain an alkaline soluble resin (i)-4. The solid content of the obtained resin was 57.0 wt%, the acid value (converted from solid content) was 126.6 mg KOH/g, and the molecular weight (Mw) analyzed by GPC was 2990. The obtained compound is a compound of general formula (1) with X ₁ being a tetravalent naphthalene ring, Y ₁ being a xylyl group, and Q ₁ being hydrogen atoms. In addition, _V1 is all of the following structure: in general formula (2) _{, R1} is a hydrogen atom, L is a general formula (3) where M is cyclohexene-1,2-diyl (the residue of 1,2,3,6-tetrahydrophthalic acid) and p=1.

[Experiment 1]

In Experiment 1, the heat resistance of the alkali-soluble resin represented by general formula (1) and the hardened film comprising a photosensitive resin thereof was evaluated.

[Evaluation]

[Heat Resistance Evaluation]

A substrate for a hardened film of alkali-soluble resin (i)-1 to alkali-soluble resin (i)-3, used for heat resistance evaluation 1 and heat resistance evaluation 2, is prepared as follows.

(Preparation of a substrate with a hardened film for heat resistance evaluation 1 and 2)

5g of the alkali-soluble resins ((i)-1~(i)-3) obtained in Synthetic Examples 1, 2, and the Comparative Synthetic Example were diluted with 5g of acetone, and then thinly spread on a 125mm × 125mm glass substrate "#1737" (manufactured by Corning Incorporated). The substrates were dried at 110°C for 60 minutes to obtain substrates with a hardened film for heat resistance evaluation 1 and heat resistance evaluation 2.

(Evaluation Methodology)

The heat resistance of the hardened film was evaluated by measuring the weight change at atmospheric conditions using a thermogravimetric differential thermal analysis (TG-DTA) apparatus. Furthermore, the measurement was performed after removing the hardened film from the glass substrate. The measurement conditions are shown in Table 1.

The results of the heat resistance evaluations 1 and 2 of the hardened film are shown in Tables 2 and 3.

As shown in Tables 2 and 3, it can be seen that the cured product of the alkali-soluble resin containing polymerizable unsaturated groups represented by general formula (1) has high heat resistance.

Next, the photosensitive resin compositions of Examples 1 and 2 were prepared using the formulation amounts (in mass %) recorded in Table 4. The formulation components used in Table 4 are as follows.

(Base-soluble resins containing polymerizable unsaturated groups)

(i)-1: The alkaline soluble resin containing polymerizable unsaturated groups obtained in Synthesis Example 1

(i)-2: The alkaline soluble resin containing polymerizable unsaturated groups obtained in Synthesis Example 2

(Photopolymerizable monomers)

(ii): Dipentaerythritol hexaacrylate

(Photopolymerization initiator)

(iii): 1-Hydrocyclohexylphenyl ketone (Omnirad 184, manufactured by IGM Resins B.V.)

(Soluble): PGMEA

A substrate having a hardened film comprising a photosensitive resin composition containing an alkali-soluble resin ((i)-1 or (i)-2) is prepared as follows for use in heat resistance evaluation 3.

(Fabrication of a substrate with a hardened film for heat resistance evaluation 3)

Using a spin coater, the photosensitive resin composition containing alkali-soluble resins ((i)-1 or (i)-2) shown in Table 4 was coated onto a glass substrate with a film thickness of 1.0 μm to 1.5 μm after baking. The coated substrate was then pre-baked at 90°C for 1 minute to create a coating plate. Subsequently, a photocuring reaction was carried out by irradiating the entire substrate with 365 nm ultraviolet light using a 500 W/ ^cm² high-pressure mercury lamp. Finally, a heat curing treatment was performed at 230°C for 30 minutes using a hot air dryer to obtain the cured film used for heat resistance evaluation 3.

(Evaluation Methodology)

The heat resistance of the hardened film used in heat resistance evaluation 3 was evaluated using the same method as described in the heat resistance evaluation. Furthermore, the hardened film on the glass substrate was removed for measurement. The measurement conditions are shown in Table 5.

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

As shown in Table 6, photosensitive resin compositions containing alkali-soluble resins represented by general formula (1) exhibit high heat resistance.

[Experiment 2]

In Experiment 2, the various properties required for the use of photosensitive resin compositions containing alkali-soluble resins represented by general formula (1) in insulating films, etc., were evaluated.

The photosensitive resin compositions of Examples 3-5 and Comparative Example 2 were prepared using the formulation amounts (in mass %) listed in Table 7. The formulation components used in Table 7 are as follows.

(Base-soluble resins containing polymerizable unsaturated groups)

(i)-1: The alkali-soluble resin obtained in Synthesis Example 1

(i)-2: The alkali-soluble resin obtained in Synthetic Example 2

(i)-3: Comparison of the alkali-soluble resin obtained in Synthesis Example 1

(i)-4: Alkali-soluble resin obtained in Synthesis Example 3

(Photopolymerizable monomers)

(ii): Dipentaerythritol hexaacrylate

(Photopolymerization initiator)

(iii)-1: Omnirad 184 (manufactured by IGM Resins B.V.)

(iii)-2: Yes, yes'-bis(dimethylamino)benzophenone (milchlerone)

(Epoxy Resin)

(iv): Cresol-phenolic varnish-type epoxy resin (YDCN-700-7, epoxy equivalent 200g/eg, softening point 70℃, manufactured by JITAC Chemicals & Materials Co., Ltd.)

(Soluble): PGMEA

[Evaluation of the photosensitive resin compositions of Examples 3-5 and Comparative Example 2]

Using a spin coater, the film thickness after baking was 10 μm. The photosensitive resin composition shown in Table 7 was coated onto a 125 mm × 125 mm glass substrate and pre-baked at 90 °C for 3 minutes to create the coating. Then, the exposed portions were photocured by irradiating the pattern-forming mask with 365 nm ultraviolet light using a 500 W/ ^cm² high-pressure mercury lamp. Next, the exposed coating was developed using a 1.0 wt% sodium carbonate aqueous solution at 23 °C for 20 seconds from the time the pattern first appeared, followed by a spray wash to remove unexposed areas of the coating. Subsequently, a hot air dryer was used to heat and harden the film at 230°C for 30 minutes to obtain the hardened films of Examples 3 to 5 and Comparative Example 2.

The hardened film was evaluated as shown below. The results are presented in Table 8.

(sensitivity)

Using a spin coater and baking process to achieve a film thickness of 10 μm, the photosensitive resin composition shown in Table 7 was coated onto a 125 mm × 125 mm glass substrate and pre-baked at 90 °C for 3 minutes to create a coated plate. Subsequently, a photocuring reaction was performed on the exposed portion by irradiating the photomask with a transmittance continuously varying from 0% to 100% with 365 nm ultraviolet light using a 500 W/ ^cm² high-pressure mercury lamp. Next, the exposed coated plate was developed using a 1.0 wt% sodium carbonate aqueous solution at 23 °C for 10 seconds from the time the pattern first appeared, followed by a spray wash to remove unexposed areas of the coating. Then, a hot air dryer was used to heat and harden the film at 230°C for 30 minutes, and the minimum exposure amount (mJ/ ^cm2 ) for the hardened film residue was calculated.

(Methods for determining adhesion and residue)

The adhesion of the fine-line pattern in the hardened film was confirmed using a VHX5000 digital microscope (manufactured by KEYENCE Corporation), and evaluated according to the following criteria.

The criteria for evaluating close contact are as follows.

○: Patterns with an L/S (linewidth/spacewidth) of 30μm or more are formed.

×: Patterns with L/S (linewidth/space width) less than 30μm/30μm were not formed.

The evaluation criteria for residue are as follows.

○: No residue between patterns in patterns with an L/S ratio of 30μm/30μm or larger.

×: In patterns with L/S ratios greater than 30μm/30μm, there is obvious residue between patterns.

(Methods for determining linearity)

The straightness of the fine line pattern in the hardened film was confirmed using a VHX5000 digital microscope (manufactured by KEYENCE Corporation), and evaluated according to the following criteria.

○: No peeling or damage to the fine line pattern relative to the glass substrate, or serrations at the ends of the pattern were found.

×: Fine lines were found to be peeling or missing from the glass substrate, or there were jagged edges at the ends of the lines.

(Conical shape)

The tapered shape was achieved using a negative photomask with a line and spatial pattern ranging from 1μm to 100μm, and the pattern after exposure and development was observed using a scanning electron microscope (VE-7800, manufactured by KEYENCE Co., Ltd.). Evaluation was performed according to the following criteria.

◎: The cross-sectional shape is nearly vertical.

○: The cross-sectional shape is trapezoidal, and the interior angle of the end of the pattern formed by the pattern side and the glass substrate is 90°~60°.

△: The cross-sectional shape is gentle and rounded.

×: The cross-sectional shape is trapezoidal, and the interior angle of the end of the pattern formed by the pattern side and the glass substrate is greater than 90°.

It can be seen that the photosensitive resin compositions containing alkali-soluble resins prepared in Examples 3 to 5, as shown in Table 8, can form hardened film patterns that combine high adhesion with residue suppression and excellent tapered shape.

Based on the above, the photosensitive resin composition containing the alkaline soluble resin of the present invention is suitable for the following applications: forming, by means of solder resists, plating resists, and etching resists used in the manufacture of circuit substrates, and for creating hardened films with excellent dimensional accuracy and pattern cross-sectional shape, such as color filters or light-shielding films for liquid crystal displays, organic EL displays, μLED displays, and image sensors, using photolithography.

This application claims priority based on Japanese Patent Application 2020-182575, filed on October 30, 2020. The entire contents of that application and its scope are incorporated herein by reference.

[Industry-level availability]

The photosensitive resin composition containing the alkaline-soluble resin of this invention is suitable as an anti-corrosion agent for solder resist, plating corrosion inhibitor, etching corrosion inhibitor, and insulating film of semiconductor devices used in the manufacture of circuit boards. Its cured form is suitable as various cured films formed by photolithography, such as protective films, color filters, and light-shielding films, for structural components of liquid crystal displays, organic EL displays, μLED displays, and image sensors.

Claims (9)

An alkaline soluble resin, represented by the following general formula (1), and having a carboxyl group and a polymerizable unsaturated group within one molecule, In formula (1), _X1 is a tetravalent substituent represented by the following general formula (5), _Y1 is a divalent substituent represented by the following general formula (6), and in the following general formulas (5) and (6), a portion of the hydrogen atom may also be substituted by a straight-chain or branched hydrocarbon with 1 to 20 carbon atoms, _V1 is a substituent represented by the following general formula (2); the value of 1 as an average value is 0.2 to 4.0; _Q1 is a hydrogen atom or a straight-chain or branched hydrocarbon with 1 to 20 carbon atoms; In equation (5), * indicates the site bonded to the oxygen atom (O), _Y1 , or _Q1 in equation (1); In equation (6), * indicates the part that is bonded to _X1 in equation (1); In formula (2), _R1 represents a hydrogen atom or a methyl group, L represents a substituent represented by the following general formula (3), and * represents the site bonded to the oxygen atom (O) in formula (1); In formula (3), M represents a divalent or trivalent residual group derived from dicarboxylic acid, tricarboxylic acid or their anhydride, p is 1 or 2, and * represents the site bonded to the oxygen atom (O) in formula (2). An alkaline soluble resin, represented by the following general formula (1), and having a carboxyl group and a polymerizable unsaturated group within one molecule, In formula (1), _X1 is a tetravalent substituent derived from naphthol, _Y1 represents a divalent group containing an aromatic ring, and part of the hydrogen atom of _X1 and _Y1 may also be substituted by a straight-chain or branched hydrocarbon with 1 to 20 carbon atoms, _V1 is a substituent represented by the following general formula (2); the value of 1 as an average value is 0.2 to 4.0; _Q1 is a hydrogen atom or a straight-chain or branched hydrocarbon with 1 to 20 carbon atoms; In formula (2), _R1 represents a hydrogen atom or a methyl group, L represents a substituent represented by the following general formula (3), and * represents the site bonded to the oxygen atom (O) in formula (1); In formula (3), M represents a divalent or trivalent residual group derived from dicarboxylic acid, tricarboxylic acid or their anhydride, p is 1 or 2, and * represents a part bonded to the oxygen atom (O) in formula (2). The alkaline soluble resin as described in claim 2, wherein _Y1 is a divalent substituent represented by the following general formula (6), in which a portion of the hydrogen atom may also be substituted by a linear or branched hydrocarbon having 1 to 20 carbon atoms. In equation (6), * indicates the part that is bonded to X ₁ in equation (1). A photosensitive resin composition comprising (i) an alkaline-soluble resin as described in any one of claims 1 to 3, (ii) a photopolymerizable monomer having at least one polymerizable unsaturated group, and (iii) a photopolymerization initiator as an essential component. The photosensitive resin composition as described in claim 4, wherein the content of component (iii) is 0.1 to 10 parts by weight relative to a total of 100 parts by weight of component (i) and component (ii). The photosensitive resin composition as described in claim 4 contains (iv) an epoxide compound. The photosensitive resin composition as described in claim 6, wherein the content of component (iv) is 10 to 40 parts by mass relative to a total of 100 parts by mass of components (i) and (ii). The photosensitive resin composition as described in claim 4 comprises (v) a dispersed phase. A curing agent is formed by curing a photosensitive resin composition as described in claim 4 or 5.