Photosensitive resin composition, cured product, and partition wall

Abstract

The purpose of the present invention is to provide a photosensitive resin composition that makes it possible to form cured products that have substantial liquid repellence, even if the photosensitive resin composition does not include or includes a small amount of an organic fluorine compound, and that also makes it possible to form thick-film patterns. This photosensitive resin composition contains: an alkali-soluble resin (A) that includes a repeating structural unit (a1) that has a hydrophobic group, a repeating structural unit (a2) that has an acid group, and a repeating structural unit (a3) that has a (meth)acryloyl group, the repeating structural unit (a1) content being more than 10 mole% but less than 45 mole%, and the double bond equivalent being 300–2000; a photopolymerizable monomer (B) that has a logP of 2.5–6.5; and a photopolymerization initiator (C).

Description

Technical Field

[0001] The present invention relates to a photosensitive resin composition capable of forming a cured product having liquid repellency.

Background Art

[0002] Conventionally, photosensitive resin compositions (resist compositions) have been used as materials for creating masks for circuit manufacturing such as semiconductor integrated circuits (ICs) and thin film transistor (TFT) circuits for liquid crystal displays (LCDs), and also as materials for forming partition walls of color filters of liquid crystal display elements, partition walls of ITO (indium tin oxide) electrodes of liquid crystal display elements, partition walls of organic EL display elements, and partition walls of circuit wiring boards. In recent years, photosensitive resin compositions have also been used as materials for forming flow paths of microfluidic chips, and the application range of this technology has been expanding more and more.

[0003] For example, in the manufacture of color filters of liquid crystal display elements, an inkjet method is adopted in which inks of each of R (red), G (green), and B (blue) are spray-coated into pixels of several tens to several hundreds of micrometers partitioned by partition walls (black matrices). The formation of pixel patterns composed of a large number of pixels is performed by photolithography using a photosensitive resin composition.

[0004] Also, in the manufacture of ITO electrodes of liquid crystal display elements, for example, when forming an ITO electrode pattern, an inkjet method in which an ITO solution is spray-coated between partition walls is adopted. The formation of an ITO electrode pattern composed of a large number of ITO electrodes is performed by photolithography using a photosensitive resin composition.

[0005] Also, in the manufacture of organic EL display elements, for example, when forming a hole transport layer or a light emitting layer within a pixel (between partition walls), an inkjet method in which a solution of a hole transport material or a light emitting material is spray-coated is adopted. The formation of pixel patterns is performed by photolithography using a photosensitive resin composition.

[0006] Furthermore, in the manufacturing of circuit wiring boards, for example, when forming circuit wiring, an inkjet method is employed in which a metal solution is sprayed between circuit wiring patterns formed by partitions. The formation of the circuit wiring patterns is carried out by photolithography using a photosensitive resin composition.

[0007] In the aforementioned inkjet method, it is necessary to prevent the mixing of inks between adjacent pixel regions and the adhesion of ITO solution, metal solution, etc., to areas other than the designated region. Therefore, the partition wall is required to have properties that repel water-based solvents, organic solvents, etc., which are inkjet coating liquids, in other words, liquid-repellent properties.

[0008] Microfluidic chips have channels that are fine channels (patterns) formed by partitions, and a technology has emerged to form these partitions using photolithography with a photosensitive resin composition.

[0009] As a method for imparting liquid-repellent properties to these partitions, it has been proposed to incorporate an organofluorine compound into a photosensitive resin composition.

[0010] For example, Patent Document 1 proposes a resist composition containing a fluorine-containing resin (A) having a fluorine atom content of 7 to 35% by mass. [Prior art documents] [Patent Documents]

[0011] [Patent Document 1] Japanese Patent Publication No. 2005-315984 [Overview of the Initiative] [Problems that the invention aims to solve]

[0012] Because organic fluorine compounds, such as fluororesins, can have adverse effects on human health and the environment, their use has been restricted by regulations in recent years. Therefore, there is a need to develop photosensitive resin compositions that can form cured products (e.g., partitions) with sufficient liquid repellency, even when they do not contain organic fluorine compounds or when they contain only small amounts of them, and that can also form relatively thick cured films with patterns (hereinafter referred to as thick-film patterns).

[0013] The present invention has been made in view of the above problems, and aims to provide a photosensitive resin composition that can form a cured product with sufficient liquid repellency and a thick film pattern, even when it does not contain an organofluorine compound or when it contains a small amount of organofluorine compounds. [Means for solving the problem]

[0014] The present invention provides the following embodiments of the invention. Item 1. An alkali-soluble resin (A) comprising repeating structural units having hydrophobic groups (a1), repeating structural units having acidic groups (a2), and repeating structural units having (meth)acryloyl groups (a3), wherein the content of the repeating structural unit (a1) is greater than 10 mol% and less than 45 mol%, and the double bond equivalent is 300 to 2000. A photopolymerizable monomer (B) with a LogP of 2.5 to 6.5, A photosensitive resin composition containing a photopolymerization initiator (C). Item 2. The photosensitive resin composition according to Item 1, wherein the hydrophobic group of the repeating structural unit (a1) is an aromatic hydrocarbon group, an alicyclic saturated hydrocarbon group, an alicyclic unsaturated hydrocarbon group, or a group to which two or more of these are bonded. Item 3. The alkali-soluble resin (A) is a photosensitive resin composition according to item 1 or 2, wherein the LogP is 1.2 to 1.9. Item 4. The alkali-soluble resin (A) is a photosensitive resin composition according to any one of items 1 to 3, wherein the acid value is 40 to 100 mg KOH / g. Item 5. The photopolymerizable monomer (B) has a functional group containing one or more ethylenically unsaturated double bonds and a ring structure, wherein the functional group is bonded to the ring structure directly or via a linking group, according to any one of items 1 to 4. Item 6. The photosensitive resin composition according to any one of items 1 to 5, wherein the photopolymerizable monomer (B) has a double bond equivalent of 90 to 400. Item 7. A cured product obtained from any of the photosensitive resin compositions described in items 1 to 6. Item 8. The cured product according to Item 7, wherein the cured product is a photospacer, partition, lens, interlayer insulating film, protective film, optical waveguide, or planarizing film. [Effects of the Invention]

[0015] The photosensitive resin composition of the present invention is characterized by containing an alkali-soluble resin (A) comprising repeating structural units having hydrophobic groups (a1), repeating structural units having acidic groups (a2), and repeating structural units having (meth)acryloyl groups (a3), wherein the content of the repeating structural units (a1) is greater than 10 mol% and less than 45 mol%, and the double bond equivalent is 300 to 2000, and a photopolymerizable monomer (B) having a LogP of 2.5 to 6.5. By using these two components, a cured product with sufficient liquid repellency can be formed even when no organofluorine compounds are included or when the content of organofluorine compounds is low. Furthermore, the photosensitive resin composition of the present invention has the advantage of easy formation of thick cured films and good pattern-forming properties. Because the photosensitive resin composition of the present invention has the above characteristics, it is suitably used as a material for forming photospacers, partitions, lenses, interlayer insulating films, protective films, optical waveguides, or planarization films. [Modes for carrying out the invention]

[0016] In this invention, (meth)acrylate means acrylate and / or methacrylate, (meth)acrylic means acrylic and / or methacrylic, (meth)acryloyl means acryloyl and / or methacryloyl, and (meth)acrylic acid means acrylic acid and / or methacrylic acid.

[0017] In the present invention, LogP is an index representing the hydrophobicity of a chemical substance, and is a value obtained by calculation using ChemDraw Professional 21.0.0 of PerkinElmer.

[0018] In the present invention, the double bond equivalent refers to the number of grams of a target compound per mole of a functional group containing an ethylenically unsaturated double bond (hereinafter also referred to as a "radical polymerizable functional group"), and is a value obtained by double bond equivalent = (amount of target compound (g) / number of radical polymerizable functional groups contained in the target compound (mol)).

[0019] In the present invention, the acid value represents the mass (mg) of potassium hydroxide required to neutralize the acid groups contained in 1 g of the target compound, and is a theoretical value calculated from the molecular weight based on the structure of the target compound and the number of functional groups per molecule (number of acid groups). Specifically, the acid value of the target compound is a value obtained by [number of moles of acid groups of the target compound (mmol)] × [56.11 / amount of target compound (g)].

[0020] Examples of the target compound in the double bond equivalent and the acid value include an alkali-soluble resin (A) and a photopolymerizable monomer (B). The structure, double bond equivalent, and acid value of the target compound, as well as the content of the target compound in the photosensitive resin composition, etc. may be specified by analyzing the photosensitive resin composition by a known method, or may be specified from the structure and ratio of the raw materials used in the production of the photosensitive resin composition.

[0021] 1. Photosensitive resin composition The photosensitive resin composition of the present invention is characterized by containing an alkali-soluble resin (A) comprising repeating structural units having hydrophobic groups (a1), repeating structural units having acidic groups (a2), and repeating structural units having (meth)acryloyl groups (a3), wherein the content of the repeating structural units (a1) is greater than 10 mol% and less than 45 mol%, and the double bond equivalent is 300 to 2000; a photopolymerizable monomer (B) having a LogP of 2.5 to 6.5; and a photopolymerization initiator (C). Furthermore, the photosensitive resin composition of the present invention is characterized by being substantially free of organofluorine compounds (organofluorine compounds are intentionally omitted), or having a reduced content of organofluorine compounds compared to conventional compositions.

[0022] The reason why a cured product with excellent liquid repellency and thick-film pattern-forming properties can be obtained from the photosensitive resin composition of the present invention is not limited by theory, but can be considered as follows. The inventors have found that when only relatively hydrophobic photopolymerizable monomers are used to improve the liquid repellency of the cured product (when the alkali-soluble resin does not have structural units with hydrophobic groups), although the liquid repellency improves, the patterning properties (especially the developability) of the cured product tend to deteriorate. In particular, it is thought that if relatively hydrophobic photopolymerizable monomers are included in the composition as they are, residue is generated and the patterning properties deteriorate because the monomers themselves have low solubility in alkali. Therefore, by including both structural units having acid groups and structural units derived from relatively hydrophobic photopolymerizable monomers in the polymer, and by increasing the content of relatively hydrophobic components (the repeating structural units having hydrophobic groups (a1) and photopolymerizable monomers (B) in the alkali-soluble resin (A) of the present invention) to a certain extent in the overall composition, while including a certain proportion of alkali-soluble components (the repeating structural units having acid groups (a2) in the alkali-soluble resin (A) of the present invention) in the composition, the content of relatively hydrophobic photopolymerizable monomers can be reduced in the uncured portion, thereby suppressing the generation of residue, while in the cured portion, a large amount of relatively hydrophobic components can be included, thus exhibiting high liquid repellency.

[0023] Embodiments of the photosensitive resin composition of the present invention include embodiments in which the organofluorine compound is included as a structural unit constituting an alkali-soluble resin, and embodiments in which it is included in the composition (i.e., as a monomer or additive). In either embodiment, the content of the organofluorine compound in the photosensitive resin composition of the present invention is preferably as low as possible while still being able to solve the problems of the present invention. For example, it can be 10% by mass or less, 5% by mass or less, or 1% by mass or less relative to the total solid content of the photosensitive resin composition, and preferably below the detection limit. The photosensitive resin composition of the present invention will be described in detail below.

[0024] [Alkali-soluble resin (A)] The alkali-soluble resin (A) contains repeating structural units having hydrophobic groups (a1), repeating structural units having acidic groups (a2), and repeating structural units having (meth)acryloyl groups (a3), wherein the content of the repeating structural units (a1) is greater than 10 mol% and less than 45 mol%, and the double bond equivalent is 300 to 2000.

[0025] <Repeating structural unit with hydrophobic groups (a1)> The monomer (a1') that forms the repeating structural unit (a1) having a hydrophobic group may have a radical polymerizable functional group and a hydrophobic group, but is not particularly limited otherwise.

[0026] The radical polymerizable functional group is not particularly limited and examples include vinyl group, allyl group, (meth)acryloyl group, (meth)acryloyloxy group, and (meth)acrylamide group, and (meth)acrylamide group are preferred from the viewpoint of polymerizability with monomers that form other structural units. The monomer (a1') may have one radical polymerizable functional group of one type, or it may have two or more radical polymerizable substituents of the same or different type, but from the viewpoint of imparting good developability to the photosensitive resin composition (hereinafter simply referred to as "from the viewpoint of developability"), it is preferred to have one.

[0027] The hydrophobic group may be any group whose LogP of monomer (a1') is 2.0 to 4.0, but is preferably an aromatic hydrocarbon group, an alicyclic saturated hydrocarbon group, an alicyclic unsaturated hydrocarbon group, or a group in which two or more of these are bonded. Examples of aromatic hydrocarbon groups include benzene rings, naphthalene rings, biphenyl rings, anthracene rings, phenanthrene rings, pyrene rings, fluorene rings, acenaphthylene rings, acenaphthene rings, and aromatic rings in which two or more of these are bonded, with benzene rings being preferred. The aromatic hydrocarbon group may have substituents such as alkyl groups, alkenyl groups, alkoxy groups, and halogen groups. Examples of alicyclic saturated hydrocarbon groups and alicyclic unsaturated hydrocarbon groups include those with 6 to 20 carbon atoms constituting the ring, preferably those with 6 to 12 carbon atoms constituting the ring, more preferably those with 6 to 10 carbon atoms constituting the ring, and may be bridged rings, fused rings, spiro rings, and alicyclic rings in which two or more of these are bonded. Alicyclic saturated hydrocarbon groups and alicyclic unsaturated hydrocarbon groups may have substituents such as alkyl groups, alkenyl groups, alkoxy groups, and halogen groups. Examples of alicyclic saturated hydrocarbon groups and alicyclic unsaturated hydrocarbon groups include the following groups. [ka]

[0028] The monomer (a1') may have one hydrophobic group of one type, or two or more hydrophobic groups of the same or different types, but from the viewpoint of developability, it is preferably one.

[0029] The radical polymerizable functional group and the hydrophobic group may be directly bonded or bonded via a linking group. The linking group is not particularly limited and includes, for example, a linear or branched aliphatic saturated hydrocarbon group or aliphatic unsaturated hydrocarbon group, or an organic group in which some of the carbon atoms constituting the hydrocarbon group are substituted with heteroatoms (e.g., oxygen, nitrogen, and sulfur atoms). Furthermore, the hydrocarbon group and the organic group may have various substituents (e.g., halogen groups, alkyl groups, alkenyl groups, and alkoxy groups) or functional groups (e.g., ester bonds, amide bonds, ether bonds, thioether bonds, and urethane bonds). From the viewpoint of developability, the linking group is preferably a linear or branched aliphatic saturated hydrocarbon group or aliphatic unsaturated hydrocarbon group having 1 to 10 carbon atoms, or an organic group in which some of the carbon atoms constituting the hydrocarbon group are substituted with oxygen atoms.

[0030] Examples of the monomer (a1') include the following monomers. Furthermore, the monomers listed below may have an acryloyloxy group instead of a methacryloyloxy group. [ka]

[0031] In the alkali-soluble resin (A), the repeating structural unit (a1) may consist of one type or two or more types.

[0032] In the alkali-soluble resin (A), the content of the repeating structural unit (a1) is, from the viewpoint of imparting sufficient liquid repellency to the cured product of the photosensitive resin composition and from the viewpoint of facilitating the formation of a thick film of the cured product of the photosensitive resin composition and forming a good thick film pattern, more than 10 mol% and less than 45 mol%, preferably 15 to 40 mol%, more preferably 20 to 35 mol%, and even more preferably 25 to 35 mol%.

[0033] <Repeating structural unit having an acid group (a2)> The monomer (a2') that forms the repeating structural unit (a2) having an acid group may be any monomer having a radical polymerizable functional group and an acid group, and is not particularly limited otherwise.

[0034] The radical polymerizable functional group is not particularly limited and examples include vinyl group, allyl group, (meth)acryloyl group, (meth)acryloyloxy group, and (meth)acrylamide group, with (meth)acryloyloxy group being preferred from the viewpoint of polymerizability with monomers that form other structural units. The monomer (a2') may have one radical polymerizable functional group, or it may have two or more radical polymerizable substituents of the same or different types, but one is preferred from the viewpoint of developability.

[0035] The acid group is not particularly limited and examples include carboxylic acid groups, sulfonic acid groups, and phosphoric acid groups, but from the viewpoint of ease of manufacturing the alkali-soluble resin (A), a carboxylic acid group is preferred. The monomer (a2') may have one acid group of one type, or two or more acid groups of the same or different types, but from the viewpoint of developability, one is preferred.

[0036] The radical polymerizable functional group and the acid group may be directly bonded or bonded via a linking group. The linking group is not particularly limited and includes, for example, a linear or branched aliphatic saturated hydrocarbon group or aliphatic unsaturated hydrocarbon group, or an organic group in which some of the carbon atoms constituting the hydrocarbon group are substituted with heteroatoms (e.g., oxygen, nitrogen, and sulfur atoms). Furthermore, the hydrocarbon group and the organic group may have various substituents (e.g., halogen groups, alkyl groups, alkenyl groups, and alkoxy groups) or functional groups (e.g., ester bonds, amide bonds, ether bonds, thioether bonds, and urethane bonds). From the viewpoint of developability, the linking group is preferably a linear or branched aliphatic saturated hydrocarbon group or aliphatic unsaturated hydrocarbon group having 1 to 10 carbon atoms, or an organic group in which some of the carbon atoms constituting the hydrocarbon group are substituted with oxygen atoms.

[0037] Examples of the monomer (a2') include carboxyl group-containing monomers such as (meth)acrylic acid, 2-(meth)acryloyloxyethyl succinic acid, maleic acid, and itaconic acid, with (meth)acrylic acid being preferred.

[0038] In the alkali-soluble resin (A), the repeating structural unit (a2) may consist of one type or two or more types.

[0039] In the alkali-soluble resin (A), the content of the repeating structural unit (a2) is not particularly limited, but from the viewpoint of imparting excellent liquid repellency to the cured product of the photosensitive resin composition and from the viewpoint of alkali developability of the photosensitive resin composition, it is preferably 1 to 50 mol%, more preferably 5 to 40 mol%, even more preferably 10 to 35 mol%, and even more preferably 20 to 30 mol%.

[0040] <(meth)acryloyl group-containing repeating structural unit (a3)> The monomer (a3') that forms the repeating structural unit (a3) ​​having a (meth)acryloyl group only needs to have a radical polymerizable functional group and a (meth)acryloyl group in one molecule, and is not particularly limited otherwise. When producing an alkali-soluble resin (A) using monomer (a3') as a raw material, theoretically, one of the radical polymerizable functional group and one or more (meth)acryloyl groups will randomly constitute the main chain of the alkali-soluble resin (A). Therefore, from the viewpoint of precisely adjusting the ratio of the structural unit (a3) ​​in the alkali-soluble resin (A), it is preferable that the radical polymerizable functional group is a (meth)acryloyl group, or that the structural unit (a3) ​​is formed by the production method described later.

[0041] The radical polymerizable functional group is not particularly limited and includes, for example, a vinyl group, an allyl group, a (meth)acryloyl group, a (meth)acryloyloxy group, and a (meth)acrylamide group. From the viewpoint of polymerizability with monomers that form other structural units, (meth)acryloyl groups and (meth)acryloyloxy groups are preferred. When the radical polymerizable functional group is a (meth)acryloyl group, monomer (a3') can be said to be a monomer having two or more (meth)acryloyl groups, and the structural unit (a3) ​​derived from the monomer has one (meth)acryloyl group polymerize with a radical polymerizable functional group of another monomer (including other monomers (a3')) to constitute the main chain of the alkali-soluble resin (A). The monomer (a3') may have one radical polymerizable functional group of one type, or it may have two or more radical polymerizable substituents of the same or different types, but from the viewpoint of developability, one is preferred.

[0042] The monomer (a3') may have one (meth)acryloyl group of one type, or two or more (meth)acryloyl groups of the same or different types, but from the viewpoint of improving the adhesion of the cured product, it is preferably one.

[0043] The radical polymerizable functional group and the (meth)acryloyl group may be directly bonded or bonded via a linking group. The linking group is not particularly limited and includes, for example, linear or branched aliphatic saturated hydrocarbon groups or aliphatic unsaturated hydrocarbon groups, and organic groups in which some of the carbon atoms constituting the hydrocarbon group are substituted with heteroatoms (e.g., oxygen atoms, nitrogen atoms, and sulfur atoms). Furthermore, the hydrocarbon group and the organic group may have various substituents (e.g., halogen groups, alkyl groups, alkenyl groups, and alkoxy groups) and functional groups (e.g., ester bonds, amide bonds, ether bonds, thioether bonds, and urethane bonds).

[0044] Examples of the monomer (a3') include the monomer represented by the following general formula (a3''). [ka] (In the formula, R 1 and R 4 Each is independently a hydrogen atom or a methyl group, and R 2 and R 3 Each of these is independently a linear or branched aliphatic saturated hydrocarbon group or aliphatic unsaturated hydrocarbon group having 1 to 10 carbon atoms.

[0045] In the alkali-soluble resin (A), the repeating structural unit (a3) ​​may consist of one type or two or more types.

[0046] In the alkali-soluble resin (A), the content of the repeating structural unit (a3) ​​is not particularly limited, but from the viewpoint of imparting excellent liquid repellency to the cured product of the photosensitive resin composition, and from the viewpoint of facilitating the formation of a thick film of the cured product of the photosensitive resin composition and forming a good thick film pattern, it is preferably 10 to 60 mol%, more preferably 15 to 55 mol%, even more preferably 15 to 50 mol%, and even more preferably 15 to 45 mol%.

[0047] <Repeating structural units (other structural units) derived from copolymer monomers> The alkali-soluble resin (A) may contain repeating structural units derived from copolymer monomers such as alkyl(meth)acrylates including methyl(meth)acrylate, ethyl(meth)acrylate, propyl(meth)acrylate, butyl(meth)acrylate, lauryl(meth)acrylate, and stearyl(meth)acrylate; hydroxyl-containing(meth)acrylates including 2-hydroxyethyl(meth)acrylate and hydroxypropyl(meth)acrylate; alkoxy-containing(meth)acrylates including ethoxyethyl(meth)acrylate; epoxy-containing(meth)acrylates including glycidyl(meth)acrylate; and maleimides including cyclohexylmaleimide, phenylmaleimide, methylmaleimide, ethylmaleimide, n-butylmaleimide, and laurylmaleimide, to the extent that it does not impair the effects of the present invention. One of these repeating structural units may be present, or two or more may be present. Of these, from the viewpoint of developability, it is preferable to include repeating structural units (a4) derived from hydroxyl group-containing (meth)acrylate. In the alkali-soluble resin (A), the content of repeating structural units (a4) derived from hydroxyl group-containing (meth)acrylate is preferably 35 mol% or less, more preferably 30 mol% or less, even more preferably 20 mol% or less, and even more preferably 10 mol% or less.

[0048] <Other configurations> The weight-average molecular weight (MW) of the alkali-soluble resin (A) is not particularly limited, but when the photosensitive resin composition is used as a resist material, it is preferably 5,000 to 100,000, more preferably 10,000 to 50,000, and even more preferably 12,000 to 20,000, from the viewpoint of obtaining good exposure sensitivity and good developability. The weight-average molecular weight is determined by gel permeation chromatography (GPC) in accordance with JIS K 7252-1:2016 and is a value converted using standard polystyrene.

[0049] The double bond equivalent of the alkali-soluble resin (A) is 300 to 2000, preferably 350 to 1500, and more preferably 400 to 1200, from the viewpoint of imparting sufficient liquid repellency to the cured product of the photosensitive resin composition, and from the viewpoint of facilitating the formation of a thick film of the cured product of the photosensitive resin composition and forming a good thick film pattern.

[0050] The LogP of the alkali-soluble resin (A) is not particularly limited, but from the viewpoint of imparting excellent liquid repellency to the cured product of the photosensitive resin composition, and from the viewpoint of obtaining good exposure sensitivity and good developability when the photosensitive resin composition is used as a resist material, it is preferably 1.2 to 1.9, more preferably 1.25 to 1.85, and even more preferably 1.3 to 1.8.

[0051] The acid value of the alkali-soluble resin (A) is not particularly limited, but from the viewpoint of imparting good developability to the photosensitive resin composition, it is preferably 40 to 100 mg KOH / g, more preferably 50 mg KOH / g or more and less than 90 mg KOH / g, and even more preferably 60 to 85 mg KOH / g.

[0052] Alkali-soluble resin (A) can be produced by known methods, for example, by radical polymerization of a monomer composition containing monomer (a1'), monomer (a2'), monomer (a3'), and optionally the copolymer monomer (particularly monomer (a4') that forms repeating structural units (a4) derived from hydroxyl group-containing (meth)acrylate). Alternatively, each repeating structural unit may be formed by radical polymerization of a monomer composition containing precursor monomers that serve as precursors for each structural unit, followed by substitution and addition reactions with the repeating structural units derived from the precursor monomers. Specifically, a first resin solution containing a first resin is produced by radical polymerization of a monomer composition containing monomer (a1'), monomer (a2'), and monomer (a3'-1), which is a precursor of monomer (a3'). Then, reactant (a3'-2) is added to the first resin solution, and the repeating structural unit (a3) ​​can be formed by reacting reactant (a3'-2) with all or part of the structural units derived from monomer (a3'-1). When the repeating structural unit (a3) ​​is derived from monomer (a3'-1) and reactant (a3'-2), depending on the ratio of these when synthesizing the alkali-soluble resin (A), the alkali-soluble resin (A) may contain repeating structural units corresponding to monomer (a3'-1), but these repeating structural units are treated as other structural units.

[0053] The alkali-soluble resin (A) may be a random copolymer, block copolymer, alternating copolymer, or periodic copolymer composed of the repeating structural unit (a1), the repeating structural unit (a2), the repeating structural unit (a3), and any repeating structural unit derived from the copolymer monomer (in particular, the repeating structural unit (a4)).

[0054] In the photosensitive resin composition, the content of alkali-soluble resin (A) is usually about 20 to 90% by mass relative to the total solid content of the photosensitive resin composition, and from the viewpoint of further improving the effects of the present invention, it is preferably 30 to 85% by mass, more preferably 40 to 80% by mass, and even more preferably 45 to 78% by mass.

[0055] [Photopolymerizable monomer (B)] The photopolymerizable monomer (B) is not particularly limited as long as its LogP is between 2.5 and 6.5.

[0056] The LogP of the photopolymerizable monomer (B) is preferably 2.8 to 6.5, more preferably 3.0 to 6.5, from the viewpoint of imparting excellent liquid repellency to the cured product of the photosensitive resin composition, and from the viewpoint of obtaining good exposure sensitivity and good developability when the photosensitive resin composition is used as a resist material.

[0057] The photopolymerizable monomer (B) preferably has one or more radical polymerizable functional groups and a ring structure in its molecule, from the viewpoint of imparting excellent liquid repellency to the cured product of the photosensitive resin composition, and from the viewpoint of obtaining good exposure sensitivity and good developability when the photosensitive resin composition is used as a resist material, and the radical polymerizable functional group is preferably bonded directly to the ring structure or via a linking group. The radical polymerizable functional group is not particularly limited, and examples include vinyl group, allyl group, (meth)acryloyl group, (meth)acryloyloxy group, and (meth)acrylamide group, but from the viewpoint of the above, (meth)acryloyl group and (meth)acryloyloxy group are preferred. The photopolymerizable monomer (B) may have one of a single type of radical polymerizable functional group, or may have two or more of the same or different types of radical polymerizable substituents, but from the viewpoint of improving the adhesion of the cured product, the number of radical polymerizable functional groups is preferably 1 to 6, more preferably 1 to 4, and even more preferably 1 or 2.

[0058] The aforementioned ring structure is not particularly limited and includes, for example, an aromatic hydrocarbon group, an alicyclic saturated hydrocarbon group, an alicyclic unsaturated hydrocarbon group, a heterocycle in which some of the carbon atoms constituting the hydrocarbon group are substituted with heteroatoms, and an organic group in which two or more of these are linked directly or via a linking group (for example, a linear or branched aliphatic saturated hydrocarbon group or aliphatic unsaturated hydrocarbon group, a heteroatom, or a group in which some of the carbon atoms constituting the hydrocarbon group are substituted with heteroatoms). Examples of the aforementioned aromatic hydrocarbon group include a benzene ring, a naphthalene ring, a biphenyl ring, an anthracene ring, a phenanthrene ring, a pyrene ring, a fluorene ring, an acenaphthene ring, and an acenaphthene ring. The aforementioned aromatic hydrocarbon group may have substituents such as alkyl groups, alkenyl groups, alkoxy groups, and halogen groups. Examples of the alicyclic saturated hydrocarbon group and alicyclic unsaturated hydrocarbon group include those having 6 to 20 carbon atoms in the ring, preferably 6 to 12 carbon atoms, and more preferably 6 to 10 carbon atoms, and may be a bridged ring, a fused ring, a spiro ring, or a polycyclic ring formed by the bonding of two or more of these. The alicyclic saturated hydrocarbon group and alicyclic unsaturated hydrocarbon group may have substituents such as alkyl groups, alkenyl groups, alkoxy groups, and halogen groups. Examples of the heteroatoms include oxygen atoms, nitrogen atoms, and sulfur atoms. The heterocycle may contain one or more heteroatoms, or one or more heteroatoms.

[0059] When the radical polymerizable functional group is bonded to the ring structure via a linking group, the linking group is not particularly limited and can be, for example, a linear or branched aliphatic saturated hydrocarbon group or an aliphatic unsaturated hydrocarbon group, or an organic group in which some of the carbon atoms constituting the hydrocarbon group are substituted with heteroatoms (e.g., oxygen atoms, nitrogen atoms, and sulfur atoms). Furthermore, the hydrocarbon group and the organic group may have various substituents (e.g., halogen groups, alkyl groups, alkenyl groups, and alkoxy groups) or functional groups (e.g., ester bonds, amide bonds, ether bonds, thioether bonds, and urethane bonds). From the viewpoint of developability, the linking group is preferably a linear or branched aliphatic saturated hydrocarbon group or an aliphatic unsaturated hydrocarbon group having 1 to 10 carbon atoms, or an organic group in which some of the carbon atoms constituting the hydrocarbon group are substituted with oxygen atoms.

[0060] Examples of photopolymerizable monomers (B) include the following monomers. Furthermore, the monomers listed below may have a methacryloyloxy group instead of an acryloyloxy group. [ka] [ka]

[0061] The double bond equivalent of the photopolymerizable monomer (B) is preferably 90 to 400, more preferably 95 to 395, and even more preferably 100 to 390, from the viewpoint of imparting excellent liquid repellency to the cured product of the photosensitive resin composition, and from the viewpoint of facilitating the formation of a thick film of the cured product of the photosensitive resin composition and forming a good thick film pattern.

[0062] In the photosensitive resin composition, the content of the photopolymerizable monomer (B) is usually about 5 to 80% by mass relative to the total solid content of the photosensitive resin composition, and from the viewpoint of further improving the effects of the present invention, it is preferably 10 to 70% by mass, more preferably 20 to 60% by mass, and even more preferably 22 to 55% by mass.

[0063] In the photosensitive resin composition, the mass ratio of the photopolymerizable monomer (B) to the alkali-soluble resin (A) [(B) / (A)] is preferably 0.1 to 2.0, more preferably 0.2 to 1.7, even more preferably 0.3 to 1.5, and even more preferably 0.3 to 1.2, from the viewpoint of further improving the effects of the present invention.

[0064] [Photopolymerization initiator (C)] The photopolymerization initiator (C) is not particularly limited and includes, for example, benzoin and its alkyl ethers such as benzoin, benzoin methyl ether, and benzoin ethyl ether; acetophenones such as acetophenone, 2,2-dimethoxy-2-phenylacetophenone, and 1,1-dichloroacetophenone; anthraquinones such as 2-methylanthraquinone, 2-amylanthraquinone, 2-t-butylanthraquinone, and 1-chloroanthraquinone; thioxanthones such as 2,4-dimethylthioxanthone, 2,4-diisopropylthioxanthone, and 2-chlorothioxanthone; ketals such as acetophenone dimethyl ketal and benzyl dimethyl ketal; benzophenones such as benzophenone; 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-propan-1-one and 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1; acylphosphine oxides and xanthones. These photopolymerization initiators may be used individually or in combination of two or more.

[0065] In the photosensitive resin composition, the content of the photopolymerization initiator (C) is not particularly limited, but when the total solid content of the photosensitive resin composition is considered to be 100% by mass, it is preferably 0.1 to 5% by mass, more preferably 0.2 to 3% by mass, and even more preferably 0.3 to 1% by mass.

[0066] [Optional ingredients] The photosensitive resin composition may contain polymerizable monomers other than photopolymerizable monomer (B) to the extent that it does not impair the effects of the present invention. Examples of polymerizable monomers include monofunctional monomers such as nonylphenylcarbitol (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, 2-ethylhexylcarbitol (meth)acrylate, N-vinylpyrrolidone, and ethoxylated-o-phenylphenol (meth)acrylate; polyfunctional aromatic vinyl monomers such as divinylbenzene, diallyl phthalate, and diallylbenzene phosphonate; (di)ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, trimethylolpropane di(meth)acrylate, bisphenol A ethylene oxide-added di(meth)acrylate, and trimethylolpropane Examples include polyfunctional (meth)acrylates such as tri(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol di(meth)acrylate, dipentaerythritol tri(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and tri(meth)acrylate of tris(hydroxyethyl) isocyanurate; and polyfunctional epoxy monomers such as bisphenol diglycidyl ether, diglycidyl phthalate ester, 3',4'-epoxycyclohexylmethyl 3,4-epoxycyclohexane carboxylate, and triglycidyl isocyanurate. These polymerizable monomers may be used individually or in combination of two or more.

[0067] The photosensitive resin composition may contain known alkali-soluble resins other than the alkali-soluble resin (A) of the present invention; radical polymerizable oligomers such as unsaturated polyesters, epoxy acrylates, urethane acrylates, and polyester acrylates; and curable resins such as epoxy resins, to the extent that the effects of the present invention are not impaired.

[0068] The photosensitive resin composition may contain a photopolymerization initiator. Examples of photopolymerization initiators include trifunctional thiol compounds such as 1,3,5-tris(3-mercaptopropionyloxyethyl)-isocyanurate, 1,3,5-tris(3-mercaptobutyloxyethyl)-isocyanurate (manufactured by Showa Denko, Karenz MT® NR1), and trimethylolpropanetris(3-mercaptopropionate); tetrafunctional thiol compounds such as pentaerythritol tetrakis(3-mercaptopropionate) and pentaerythritol tetrakis(3-mercaptobutyrate) (manufactured by Showa Denko, Karenz MT® PEI); and polyfunctional thiol compounds such as dipentaerythritol hexakis(3-propionate). These photopolymerization initiators may be used alone or in combination of two or more.

[0069] The photosensitive resin composition may contain a thermal polymerization initiator. Examples of thermal polymerization initiators include organic peroxides such as cumene hydroperoxide, diisopropylbenzene peroxide, di-t-butyl peroxide, lauryl peroxide, benzoyl peroxide, t-butyl peroxyisopropyl carbonate, t-butyl peroxy-2-ethylhexanoate, and t-amyl peroxy-2-ethylhexanoate; and azo compounds such as 2,2'-azobis(isobutyronitrile), 1,1'-azobis(cyclohexanecarbonile), 2,2'-azobis(2,4-dimethylvaleronitrile), and dimethyl-2,2'-azobis(2-methylpropionate). These thermal polymerization initiators may be used alone or in combination of two or more.

[0070] The photosensitive resin composition may contain a solvent. Examples of solvents include ethers such as tetrahydrofuran, dioxane, ethylene glycol dimethyl ether, and diethylene glycol dimethyl ether; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; esters such as ethyl acetate, butyl acetate, propylene glycol monomethyl ether acetate, and 3-methoxybutyl acetate; alcohols such as methanol, ethanol, isopropanol, n-butanol, ethylene glycol monomethyl ether, and propylene glycol monomethyl ether; aromatic hydrocarbons such as toluene, xylene, and ethylbenzene; and chloroform and dimethyl sulfoxide. These solvents may be used individually or in combination of two or more. The solvent content should be appropriately set according to the optimal viscosity when using the curable resin composition.

[0071] The photosensitive resin composition may contain known additives such as fillers (aluminum hydroxide, talc, clay, barium sulfate, etc.), crosslinking agents, dyes, pigments, defoaming agents, coupling agents, leveling agents, sensitizers, mold release agents, lubricants, plasticizers, antioxidants, ultraviolet absorbers, flame retardants, polymerization inhibitors, thickeners, and dispersants, to the extent that they do not impair the effects of the present invention.

[0072] 2.Cured product The cured product of the present invention is obtained by curing the photosensitive resin composition and exhibits excellent liquid repellency, particularly water repellency. A method for producing the cured product includes, for example, coating the photosensitive resin composition onto a substrate or various functional layers to form a desired shape, and then curing the photosensitive resin composition by irradiating it with light (e.g., ultraviolet light). However, the method is not limited to this, and known methods can be adopted depending on the purpose and application of forming the cured product. The curing conditions are appropriately adjusted according to the photosensitive resin composition used.

[0073] The cured product of the present invention is suitably used as a cured product having a pattern shape, such as a photospacer, partition wall, lens, interlayer insulating film, protective film, optical waveguide, and planarization film.

[0074] The method for forming a cured product having a patterned shape is not particularly limited. For example, the photosensitive resin composition can be applied to a substrate or various functional layers, dried to form a coating film, and then formed by photolithography. In photolithography, either a positive or negative type may be used, but a negative type is preferred from the viewpoint of easily forming a thick film pattern. As a method for forming a cured product having a patterned shape in negative type photolithography, for example, a photomask is placed on the coating film, the coating film is photocured by irradiation with ultraviolet light, an alkaline aqueous solution is sprayed onto the coating film after ultraviolet irradiation to dissolve and remove the unexposed areas, and the remaining exposed areas are washed with water and developed to form a cured product having a patterned shape composed of many partitions. Post-baking may be performed thereafter.

[0075] By using the photosensitive resin composition of the present invention, it is possible to manufacture thick film patterns with relatively thick film thicknesses of 10 μm or more, 20 μm or more, 30 μm or more, and even 50 μm or more. Furthermore, these thick film patterns have high adhesion to the substrate after development (high developability) and can be made into high-resolution patterns. Note that the film thickness of the thick film pattern refers to the height of the cured portion in the thick film pattern, and is the height of the partition when the cured portion is used as a partition. [Examples]

[0076] The present invention will be described below with reference to examples, but the present invention is not limited in any way by these examples.

[0077] Manufacturing Example 1 [Synthesis of alkali-soluble resin (A-1)] In a glass flask equipped with a heating / cooling / stirring device, reflux condenser, and nitrogen inlet tube, 100.0 g of dicyclopentanyl methacrylate, 32.6 g of methacrylic acid, 88.6 g of 2-hydroxyethyl methacrylate, and 331.8 g of propylene glycol monomethyl ether acetate (PGMEA) were charged. After replacing the gas phase in the system with nitrogen, 11.2 g of 2,2'-azobisisobutyronitrile was added, and the mixture was heated to 80°C and reacted at the same temperature for 8 hours to obtain a resin solution containing the first resin. Subsequently, 81.1 g of 2-(acryloyloxy)ethyl isocyanate (AOI) and 0.01 g of hydroquinone were added to the first resin solution, and the mixture was thoroughly stirred at 65°C for 10 hours to obtain a solution containing an alkali-soluble resin (A-1). The synthesized alkali-soluble resin (A-1) contains 30 mol% of repeating structural units (a1-1) derived from dicyclopentanyl methacrylate, 25 mol% of repeating structural units (a2-1) derived from methacrylic acid, 38 mol% of repeating structural units (a3-1) represented by the following formula, and 7 mol% of repeating structural units (a4-1) derived from 2-hydroxyethyl methacrylate. The synthesized alkali-soluble resin (A-1) also has an acid value of 70 mgKOH / g, a weight-average molecular weight (Mw) of 14,000 according to GPC (standard substance: polystyrene), a LogP of 1.61, and a double bond equivalent of 526. [ka]

[0078] Manufacturing Examples 2-7 [Synthesis of alkali-soluble resins (A-2) to (A-4), (A'-1) to (A'-3)] Solutions containing alkali-soluble resins (A-2), (A-3), (A-4), (A'-1), (A'-2), and (A'-3), each having the repeating structural units listed in Table 1, were obtained using the same method as in Production Example 1. The repeating structural unit (a5-1) in Table 1 is a repeating structural unit derived from methyl methacrylate. The acid value, weight-average molecular weight, LogP, and double bond equivalent of each synthesized alkali-soluble resin are as shown in Table 1.

[0079] [Table 1]

[0080] Example 1 [Preparation of photosensitive resin composition] A photosensitive resin composition with a solid content of 50% by mass was prepared by mixing a solution containing alkali-soluble resin (A-1) at a concentration of 62.2% by mass (solids), an acrylic monomer (B-1) represented by the following formula at a concentration of 37.3% by mass, and a photopolymerization initiator (C) of trade name IrgacureOXE01 (manufactured by BASF Japan Ltd.). The acrylic monomer (B-1) has a LogP of 4.54 and a double bond equivalent of 332. [ka]

[0081] Examples 2-8, Comparative Examples 1-5 [Preparation of photosensitive resin composition] A photosensitive resin composition was prepared in the same manner as in Example 1, except that the formulation was changed as shown in Table 2. The acrylic monomer (B-2) and acrylic monomer (B') in Table 2 are represented by the following formulas. Acrylic monomer (B-2) has a LogP of 3.05 and a double bond equivalent of 152. Acrylic monomer (B') has a LogP of 2.36 and a double bond equivalent of 129. [ka] [ka]

[0082] [Table 2]

[0083] Next, the contact angle, water repellency, and thick film pattern formation properties of each photosensitive resin composition prepared in Examples 1-8 and Comparative Examples 1-5 were measured or evaluated using the following methods. The results are shown in Table 2.

[0084] [Contact angle] Each curable resin composition prepared in Examples 1-8 and Comparative Examples 1-5 was applied to a glass substrate by spin coating and heated on a 100°C hot plate for 120 seconds to form a coating film. The coating film was then exposed to light from an ultra-high pressure mercury lamp at a density of 100 mJ / cm². 2 Irradiation (Illuminance at 365nm: 20mW / cm²) 2 The material was then developed using a 0.4% NaOH aqueous solution for 110 seconds, and a cured film was formed by heating at 230°C for 30 minutes. Next, the contact angle was measured by dropping 1 μL of water onto the cured film using a contact angle measuring device [Kyowa Interface Science Co., Ltd., part number: DM-501].

[0085] [Water repellency] Water repellency was evaluated based on the contact angle obtained, according to the following criteria. A higher contact angle indicates superior water repellency. A: Contact angle of 80° or more B: Contact angle is less than 75° to 80° C: Contact angle less than 75°

[0086] [Thick film pattern formation ability] Each curable resin composition prepared in Examples 1-8 and Comparative Examples 1-5 was applied to a glass substrate by spin coating and pre-baked on a 100°C hot plate for 120 seconds to form a coating film. Subsequently, the coating film was exposed to light from a 150 μm exposure gap and a 100 mJ / cm² ultra-high pressure mercury lamp. 2 Irradiated (illuminance at 365nm: 20mW / cm²) 2 Subsequently, the substrate was developed using a 0.4% NaOH aqueous solution for 110 seconds and heated at 230°C for 30 minutes to form a cured film with a thickness of 50 μm, thereby creating a substrate with a cured film. The thick film pattern formation ability was then evaluated according to the following criteria. A: With a spacing of 100 μm, a pattern with a line width of 20 μm can be formed. B: With a spacing of 100 μm, a pattern with a line width of 30 μm can be formed. C: When the spacing is 100 μm, a pattern cannot be formed (residue is generated).

[0087] The results shown in Table 2 indicate that each curable resin composition from Examples 1 to 8 can form a cured film with excellent water repellency without the use of organofluorine compounds, and also exhibits excellent thick-film pattern formation. On the other hand, the cured films formed from each curable resin composition from Comparative Examples 1 to 3 exhibit poor water repellency. Furthermore, each curable resin composition from Comparative Examples 4 and 5 exhibits poor thick-film pattern formation. [Industrial applicability]

[0088] The curable resin composition of the present invention is suitably used as a material for forming photospacers, partitions, lenses, interlayer insulating films, protective films, optical waveguides, or planarization films.

Claims

1. An alkali-soluble resin (A) comprising repeating structural units having hydrophobic groups (a1), repeating structural units having acidic groups (a2), and repeating structural units having (meth)acryloyl groups (a3), wherein the content of the repeating structural unit (a1) is greater than 10 mol% and less than 45 mol%, and the double bond equivalent is 300 to 2000, A photopolymerizable monomer (B) having a LogP of 2.5 to 6.5, A photosensitive resin composition containing a photopolymerization initiator (C).

2. The photosensitive resin composition according to claim 1, wherein the hydrophobic group of the repeating structural unit (a1) is an aromatic hydrocarbon group, an alicyclic saturated hydrocarbon group, an alicyclic unsaturated hydrocarbon group, or a group to which two or more of these are bonded.

3. The photosensitive resin composition according to claim 1, wherein the alkali-soluble resin (A) has a LogP of 1.2 to 1.

9.

4. The photosensitive resin composition according to claim 1, wherein the alkali-soluble resin (A) has an acid value of 40 to 100 mgKOH / g.

5. The photopolymerizable monomer (B) has a functional group containing one or more ethylenically unsaturated double bonds and a ring structure, wherein the functional group is bonded to the ring structure directly or via a linking group, according to claim 1, the photosensitive resin composition.

6. The photosensitive resin composition according to claim 1, wherein the photopolymerizable monomer (B) has a double bond equivalent of 90 to 400.

7. A cured product obtained from the photosensitive resin composition according to any one of claims 1 to 6.

8. The cured product according to claim 7, wherein the cured product is a photospacer, a partition, a lens, an interlayer insulating film, a protective film, an optical waveguide, or a planarizing film.

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