Polymer, photosensitive resin composition, photosensitive element, method for forming resist pattern, and method for forming wiring pattern

Abstract

One aspect of the present disclosure relates to a polymer including a structural unit represented by the following formula (I) and a structural unit having a carboxy group. 1 represents a hydrogen atom or a methyl group, M represents an alkylene group or an alkylene oxide chain, R 2 represents an alkyl group or an aryl group. TIFF2024535274000008.tif50149

Description

[Technical Field]

[0001] The present disclosure relates to a polymer, a photosensitive resin composition, a photosensitive element, a method for forming a resist pattern, and a method for forming a wiring pattern. [Background technology]

[0002] In the field of printed wiring board manufacturing, photosensitive elements (laminates) comprising photosensitive resin compositions and layers formed on support films using the photosensitive resin compositions (hereinafter also referred to as "photosensitive layers") are widely used as resist materials for etching processes, plating processes, and the like.

[0003] A printed wiring board is manufactured using the photosensitive element, for example, by the following procedure. That is, first, the photosensitive layer of the photosensitive element is laminated onto a circuit-forming substrate such as a copper-clad laminate. Next, the photosensitive layer is exposed to light through a mask film or the like to form a photocured portion. At this time, the support film is peeled off before or after exposure. Thereafter, areas of the photosensitive layer other than the photocured portion are removed with a developer to form a resist pattern. Next, using the resist pattern as a resist, an etching process or a plating process is performed to form a conductor pattern, and finally, the photocured portion (resist pattern) of the photosensitive layer is peeled off (removed).

[0004] Photosensitive resin compositions are required to be able to form resist patterns with excellent resolution, and also to have excellent peeling properties for the resist patterns (see, for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2005-122123 [Patent Document 2] Patent Publication No. 2006-234995 Summary of the Invention [Problem to be solved by the invention]

[0006] Photosensitive resin compositions are required to not only form resist patterns with excellent resolution and peeling properties, but also to have excellent conformability to a circuit-forming substrate when a photosensitive layer is laminated onto the circuit-forming substrate.The present disclosure aims to provide a novel polymer used in a photosensitive resin composition with excellent conformability during lamination, a photosensitive resin composition, a photosensitive element, a method for forming a resist pattern, and a method for forming a wiring pattern. [Means for solving the problem]

[0007] One aspect of the present disclosure relates to a polymer including a structural unit represented by the following formula (I) and a structural unit having a carboxy group: 1 represents a hydrogen atom or a methyl group, M represents an alkylene group or an alkylene oxide chain, and R 2 represents an alkyl group or an aryl group. [ka]

[0008] Another aspect of the present disclosure relates to a photosensitive resin composition containing a binder resin containing the above-mentioned polymer, a photopolymerizable compound, and a photopolymerization initiator.

[0009] Another aspect of the present disclosure also relates to a photosensitive element comprising a support and a photosensitive layer formed on the support, the photosensitive layer containing the above-described photosensitive resin composition.

[0010] Another aspect of the present disclosure relates to a method for forming a resist pattern, comprising the steps of: forming a photosensitive layer on a substrate using the photosensitive resin composition or photosensitive element; irradiating at least a portion of the photosensitive layer with actinic rays to form a photocured portion; and removing at least a portion of the photosensitive layer other than the photocured portion from the substrate.

[0011] Another aspect of the present disclosure relates to a method for forming a wiring pattern, comprising a step of etching or plating a substrate on which a resist pattern has been formed by the method for forming a resist pattern to form a conductor pattern. [Effects of the Invention]

[0012] According to the present disclosure, it is possible to provide a novel polymer used in a photosensitive resin composition having excellent conformability during lamination, a photosensitive resin composition, a photosensitive element, a method for forming a resist pattern, and a method for forming a wiring pattern. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a schematic cross-sectional view illustrating one embodiment of a photosensitive element. [Figure 2] 1 is an electron microscope photograph of a resist pattern formed in Example 5. [Figure 3] 1 is an electron microscope photograph of a resist pattern formed in Comparative Example 2. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, embodiments of the present disclosure will be described in detail, but the present disclosure is not limited to the following embodiments.

[0015] In this specification, the term "process" includes not only an independent process but also a process that cannot be clearly distinguished from other processes as long as the process achieves its intended effect. A numerical range indicated using "to" indicates a range that includes the numerical values ​​before and after "to" as the minimum and maximum values, respectively. The term "layer" encompasses not only a structure that is formed over the entire surface when observed in a plan view, but also a structure that is formed on only a portion of the surface. "(Meth)acrylic acid" means at least one of "acrylic acid" and the corresponding "methacrylic acid." The same applies to other similar expressions such as (meth)acrylate and (meth)acryloyl.

[0016] In this specification, when multiple substances corresponding to each component are present, the amount of each component in the photosensitive resin composition refers to the total amount of those multiple substances present in the photosensitive resin composition, unless otherwise specified. In the numerical ranges described in this specification, the upper or lower limit of the numerical range may be replaced with a value shown in the Examples. Furthermore, embodiments in which the descriptions in this specification are arbitrarily combined are also included in the present invention. In this specification, the term "solid content" refers to the non-volatile content of the photosensitive resin composition excluding volatile substances such as water and solvents. In other words, the term "solid content" refers to components other than the solvent that remain unvolatilized during drying of the photosensitive resin composition, as described below, and includes liquid, starch syrup-like, and wax-like components at room temperature (25°C).

[0017] [Polymer] The polymer according to this embodiment contains a structural unit represented by the following formula (I) and a structural unit having a carboxy group. [ka]

[0018] In formula (I), R 1 represents a hydrogen atom or a methyl group, M represents an alkylene group or an alkylene oxide chain, and R 2 represents an alkyl group or an aryl group.

[0019] The number of carbon atoms in the alkylene group may be 1 to 6, 1 to 4, or 1 to 3. The number of repeating alkylene oxide units in the alkylene oxide chain may be 1 to 10, 1 to 8, or 1 to 6, and the number of carbon atoms in the alkylene oxide may be 2 to 10, 2 to 6, or 2 to 4. M may be a methylene group, an ethylene group, a propylene group, a butylene group, an ethylene oxide chain, or a propylene oxide chain.

[0020] The number of carbon atoms in the alkyl group may be 1 to 20, 2 to 10, or 3 to 6. The number of carbon atoms in the aryl group may be 6 to 20, 6 to 15, or 6 to 10. R 2may be a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, or a phenyl group.

[0021] The monomer that provides the structural unit represented by formula (I) can be a reaction product of a (meth)acrylate compound having an isocyanate group and an amine compound. Examples of the (meth)acrylate compound having an isocyanate group include isocyanatomethyl (meth)acrylate, 2-isocyanatoethyl (meth)acrylate, 3-isocyanatopropyl (meth)acrylate, 2-isocyanatopropyl (meth)acrylate, 2-isocyanato-1-methylethyl (meth)acrylate, 2-isocyanatobutyl (meth)acrylate, and 2-(2-(meth)acryloyloxyethyloxy)ethyl isocyanate. Examples of the amine compound include ethylamine, propylamine, butylamine, pentylamine, hexylamine, 2-methoxyethylamine, 3-methoxyethylamine, and aniline.

[0022] The polymer according to the present embodiment contains a structural unit represented by formula (I), and when used as a photosensitive resin composition, it can improve conformability during lamination. The inventors believe that this effect is due to the polymer having a urea bond and a carboxy group in its side chain, which causes interactions between the urea bonds or between the urea bond and the carboxy group through hydrogen bonding.

[0023] The content of the structural unit represented by formula (I) in the polymer is preferably 5 to 50 mass % based on the total amount of the polymer. From the viewpoint of further improving conformability, the content of the structural unit represented by formula (I) may be 6 mass % or more, 7 mass % or more, or 8 mass % or more. From the viewpoint of increasing the solubility of the polymer in alkaline aqueous solutions, the content of the structural unit represented by formula (I) may be 45 mass % or less, 40 mass % or less, or 35 mass % or less.

[0024] From the viewpoint of alkaline developability, the polymer according to this embodiment contains a structural unit having a carboxy group. The content of the structural unit having a carboxy group may be 10 to 45 mass %, 15 to 40 mass %, or 20 to 35 mass % based on the total amount of the polymer, in order to improve alkaline developability and alkaline resistance in a well-balanced manner. When the content of the structural unit having a carboxy group is 10 mass % or more, alkaline developability tends to be improved, and when it is 45 mass % or less, alkaline resistance tends to be excellent.

[0025] Examples of monomers that provide structural units having a carboxy group include (meth)acrylic acid, α-bromoacrylic acid, α-chloroacrylic acid, β-furyl(meth)acrylic acid, β-styryl(meth)acrylic acid, maleic acid, maleic anhydride, maleic acid monoesters such as monomethyl maleate, monoethyl maleate, and monoisopropyl maleate, fumaric acid, cinnamic acid, α-cyanocinnamic acid, itaconic acid, crotonic acid, and propiolic acid. The polymer according to the embodiment preferably contains a structural unit based on (meth)acrylic acid in order to further improve alkaline developability.

[0026] From the viewpoint of adhesion and release properties, the polymer according to this embodiment may have a structural unit based on styrene or a styrene derivative. A styrene derivative is a polymerizable compound in which a hydrogen atom at the α-position or on the aromatic ring of styrene is substituted. Examples of styrene derivatives include vinyltoluene, α-methylstyrene, p-methylstyrene, and p-ethylstyrene.

[0027] The content of structural units based on styrene or a styrene derivative in the polymer may be 10 to 60 mass%, 15 to 55 mass%, or 25 to 50 mass%, based on the total amount of the polymer. When the content of structural units based on styrene or a styrene derivative is 10 mass% or more, adhesion tends to be improved, while when it is 60 mass% or less, peeled pieces can be prevented from becoming large during development, and the time required for peeling tends to be kept from increasing.

[0028] From the viewpoints of resolution and aspect ratio, the polymer according to this embodiment may have structural units based on benzyl (meth)acrylate or a benzyl (meth)acrylate derivative. Examples of benzyl (meth)acrylate derivatives include 4-methylbenzyl (meth)acrylate. From the viewpoint of improving resolution, the content of structural units based on benzyl (meth)acrylate or a benzyl (meth)acrylate derivative in the polymer may be 5 to 40 mass%, 10 to 40 mass%, or 15 to 30 mass%, based on the total amount of the polymer.

[0029] From the viewpoint of improving plasticity, the polymer according to this embodiment may have a structural unit based on a (meth)acrylic acid alkyl ester. Examples of the (meth)acrylic acid alkyl ester include methyl (meth)acrylic acid ester, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, undecyl (meth)acrylate, and dodecyl (meth)acrylate.

[0030] From the viewpoint of improving resolution, the weight average molecular weight (Mw) of the polymer may be 5,000 or more, 6,000 or more, 7,000 or more, or 8,000 or more. From the viewpoint of enabling suitable development, the Mw of the polymer may be 30,000 or less, 28,000 or less, 26,000 or less, or 24,000 or less. Mw can be measured by gel permeation chromatography (GPC) using a calibration curve of standard polystyrene.

[0031] [Photosensitive resin composition] The photosensitive resin composition according to this embodiment contains (A) a binder resin (hereinafter sometimes referred to as "component (A)"), (B) a photopolymerizable compound (hereinafter sometimes referred to as "component (B)"), and (C) a photopolymerization initiator (hereinafter sometimes referred to as "component (C)"). Each component that may be contained in the photosensitive resin composition will be described in detail below.

[0032] (binder resin) The binder resin, which is the component (A), contains a polymer having the specific structure described above (hereinafter, sometimes referred to as "component (A1)"). Use of component (A1) can improve the conformability of the photosensitive resin composition (photosensitive layer) during lamination. Component (A1) may be composed of only one type of resin, or may contain two or more types of resins.

[0033] Component (A) may further contain a resin other than component (A1). Such a resin may be an alkali-soluble resin having a phenolic hydroxyl group. Examples of resins having a phenolic hydroxyl group include hydroxystyrene-based resins such as polyhydroxystyrene and copolymers containing hydroxystyrene as a monomer unit, phenolic resins, polybenzoxazole precursors such as poly(hydroxyamide), poly(hydroxyphenylene) ether, and polynaphthol.

[0034] The content of component (A) may be 30 to 90 parts by mass, 40 to 85 parts by mass, or 50 to 80 parts by mass, relative to 100 parts by mass of the total amount of components (A) and (B). When the content of component (A) is within this range, the strength of the photocured portion of the photosensitive layer is improved.

[0035] (Photopolymerizable compound) The photopolymerizable compound of component (B) is a compound having a functional group with an ethylenically unsaturated bond, such as a vinyl group, allyl group, propargyl group, butenyl group, ethynyl group, phenylethynyl group, maleimide group, nadimide group, or (meth)acryloyl group, as a functional group exhibiting photopolymerization. Component (B) is not particularly limited as long as it is a compound having one or more ethylenically unsaturated groups. The photopolymerizable functional group is preferably a (meth)acryloyl group. Component (B) may be used alone or in combination of two or more types.

[0036] Examples of photopolymerizable compounds having one ethylenically unsaturated group include (meth)acrylic acid, (meth)acrylic acid alkyl esters, and phthalic acid compounds.

[0037] Examples of the (meth)acrylic acid alkyl ester include (meth)acrylic acid methyl ester, (meth)acrylic acid ethyl ester, (meth)acrylic acid butyl ester, (meth)acrylic acid 2-ethylhexyl ester, and (meth)acrylic acid hydroxylethyl ester.

[0038] From the viewpoint of suitably improving resolution, adhesion, and resist profile, component (B) may contain a phthalic acid compound, such as γ-chloro-β-hydroxypropyl-β'-(meth)acryloyloxyethyl-o-phthalate (also known as 3-chloro-2-hydroxypropyl-2-(meth)acryloyloxyethyl phthalate), β-hydroxyethyl-β'-(meth)acryloyloxyethyl-o-phthalate, and β-hydroxypropyl-β'-(meth)acryloyloxyethyl-o-phthalate.

[0039] Examples of photopolymerizable compounds having two ethylenically unsaturated groups include polyethylene glycol di(meth)acrylate, trimethylolpropane di(meth)acrylate, polypropylene glycol di(meth)acrylate, 2,2-bis(4-(meth)acryloxypolyethoxypolypropoxyphenyl)propane, bisphenol A diglycidyl ether di(meth)acrylate, and alkylene oxide-modified bisphenol A di(meth)acrylate.

[0040] From the viewpoint of improving alkali developability and resolution, component (B) may contain an alkylene oxide-modified bisphenol A di(meth)acrylate. Examples of alkylene oxide-modified bisphenol A di(meth)acrylates include 2,2-bis(4-((meth)acryloxypolyethoxy)phenyl)propane (2,2-bis(4-((meth)acryloxypentaethoxy)phenyl)propane, etc.), 2,2-bis(4-((meth)acryloxypolypropoxy)phenyl)propane, 2,2-bis(4-((meth)acryloxypolybutoxy)phenyl)propane, and 2,2-bis(4-((meth)acryloxypolyethoxypolypropoxy)phenyl)propane.

[0041] Examples of photopolymerizable compounds having three or more ethylenically unsaturated groups include (meth)acrylates having a skeleton derived from trimethylolpropane, such as trimethylolpropane tri(meth)acrylate; (meth)acrylates having a skeleton derived from tetramethylolmethane, such as tetramethylolmethane tri(meth)acrylate and tetramethylolmethane tetra(meth)acrylate; (meth)acrylates having a skeleton derived from pentaerythritol, such as pentaerythritol tri(meth)acrylate and pentaerythritol tetra(meth)acrylate; (meth)acrylates having a skeleton derived from dipentaerythritol, such as dipentaerythritol penta(meth)acrylate and dipentaerythritol hexa(meth)acrylate; (meth)acrylates having a skeleton derived from ditrimethylolpropane, such as ditrimethylolpropane tetra(meth)acrylate; and (meth)acrylates having a skeleton derived from diglycerin. Among these, from the viewpoint of increasing the chemical resistance after curing (exposure) and increasing the difference in developer resistance between exposed and unexposed areas, a (meth)acrylate compound having a skeleton derived from dipentaerythritol is preferred, and dipentaerythritol penta(meth)acrylate is more preferred.

[0042] In order to improve the alkali developability of the unexposed areas of the photosensitive resin composition and the adhesive strength of the exposed areas, component (B) may contain a photopolymerizable compound having an ethylenically unsaturated group and an acid-modifiable group. Examples of the acidic group to be modified include a carboxy group, a sulfo group, and a phenolic hydroxyl group, and among these, a carboxy group is preferred.

[0043] Examples of photopolymerizable compounds having an ethylenically unsaturated group and an acidic group include styrene-maleic acid resins and acid-modified vinyl group-containing epoxy derivatives.

[0044] The styrene-maleic acid resin is a hydroxyethyl (meth)acrylate-modified styrene-maleic anhydride copolymer. The acid-modified vinyl group-containing epoxy derivative is a compound obtained by reacting a compound obtained by modifying an epoxy resin with a vinyl group-containing organic acid with a saturated or unsaturated group-containing polybasic acid anhydride.

[0045] The epoxy resin is not particularly limited as long as it is a compound having two or more epoxy groups. Examples of the epoxy resin include glycidyl ether type epoxy resins, glycidyl amine type epoxy resins, and glycidyl ester type epoxy resins. Among these, from the viewpoint of reliability during semiconductor chip mounting, bisphenol novolac type epoxy resins are preferred, and bisphenol F novolac type epoxy resins are more preferred.

[0046] The vinyl group-containing organic acid is not particularly limited and may be a vinyl group-containing monocarboxylic acid. Examples of the vinyl group-containing monocarboxylic acid include acrylic acid, acrylic acid dimers, methacrylic acid, β-furfurylacrylic acid, β-styrylacrylic acid, cinnamic acid, crotonic acid, α-cyanocinnamic acid and other acrylic acid derivatives; half-ester compounds which are reaction products of hydroxyl group-containing acrylates and dibasic acid anhydrides; and half-ester compounds which are reaction products of vinyl group-containing monoglycidyl ethers or vinyl group-containing monoglycidyl esters and dibasic acid anhydrides.

[0047] Examples of photopolymerizable compounds having an α,β-unsaturated carbonyl group include α,β-unsaturated carboxylic acid esters of polyhydric alcohols, bisphenol-type (meth)acrylates, α,β-unsaturated carboxylic acid adducts of glycidyl group-containing compounds, (meth)acrylates having a urethane bond, nonylphenoxypolyethyleneoxyacrylate, and (meth)acrylic acid alkyl esters.

[0048] Examples of the α,β-unsaturated carboxylic acid ester of a polyhydric alcohol include polyethylene glycol di(meth)acrylate having 2 to 14 ethylene groups, polypropylene glycol di(meth)acrylate having 2 to 14 propylene groups, polyethylene-polypropylene glycol di(meth)acrylate having 2 to 14 ethylene groups and 2 to 14 propylene groups, trimethylolpropane di(meth)acrylate, trimethylolpropane tri(meth)acrylate, EO-modified trimethylolpropane tri(meth)acrylate, PO-modified trimethylolpropane tri(meth)acrylate, EO,PO-modified trimethylolpropane tri(meth)acrylate, tetramethylolmethane tri(meth)acrylate, tetramethylolmethane tetra(meth)acrylate, and (meth)acrylate compounds having a skeleton derived from dipentaerythritol or pentaerythritol. "EO modified" means that it has a block structure of ethylene oxide (EO) groups, and "PO modified" means that it has a block structure of propylene oxide (PO) groups.

[0049] From the viewpoint of improving the flexibility of the resist pattern, component (B) may contain a polyalkylene glycol di(meth)acrylate. The polyalkylene glycol di(meth)acrylate may have at least one of an EO group and a PO group, or may have both an EO group and a PO group. In a polyalkylene glycol di(meth)acrylate having both an EO group and a PO group, the EO groups and the PO groups may be present in succession in a block form or randomly. The PO group may be either an oxy-n-propylene group or an oxyisopropylene group. In the (poly)oxyisopropylene group, the secondary carbon of the propylene group may be bonded to an oxygen atom, or the primary carbon may be bonded to an oxygen atom.

[0050] Commercially available polyalkylene glycol di(meth)acrylates include, for example, FA-023M (manufactured by Showa Denko Materials Co., Ltd.), FA-024M (manufactured by Showa Denko Materials Co., Ltd.), and NK Ester HEMA-9P (manufactured by Shin-Nakamura Chemical Co., Ltd.).

[0051] From the viewpoint of improving the flexibility of the resist pattern, component (B) may contain a (meth)acrylate having a urethane bond. Examples of (meth)acrylates having a urethane bond include an addition reaction product of a (meth)acrylic monomer having an OH group at the β-position with a diisocyanate (such as isophorone diisocyanate, 2,6-toluene diisocyanate, 2,4-toluene diisocyanate, or 1,6-hexamethylene diisocyanate), tris((meth)acryloxytetraethylene glycol isocyanate)hexamethylene isocyanurate, EO-modified urethane di(meth)acrylate, and EO,PO-modified urethane di(meth)acrylate.

[0052] Commercially available EO-modified urethane di(meth)acrylates include, for example, "UA-11" and "UA-21EB" (manufactured by Shin-Nakamura Chemical Co., Ltd.). Commercially available EO,PO-modified urethane di(meth)acrylates include, for example, "UA-13" (manufactured by Shin-Nakamura Chemical Co., Ltd.).

[0053] From the viewpoints of facilitating the formation of a thick resist pattern and achieving a balanced improvement in resolution and adhesion, component (B) may contain a (meth)acrylate compound having a skeleton derived from dipentaerythritol or pentaerythritol. The (meth)acrylate compound having a skeleton derived from dipentaerythritol preferably has four or more (meth)acryloyl groups, and may be dipentaerythritol penta(meth)acrylate or dipentaerythritol hexa(meth)acrylate.

[0054] From the viewpoint of further improving resolution and release properties after curing, component (B) may contain a bisphenol-type (meth)acrylate, and among bisphenol-type (meth)acrylates, it may contain bisphenol A-type (meth)acrylate. Examples of bisphenol A-type (meth)acrylates include 2,2-bis(4-((meth)acryloxypolyethoxy)phenyl)propane, 2,2-bis(4-((meth)acryloxypolypropoxy)phenyl)propane, 2,2-bis(4-((meth)acryloxypolybutoxy)phenyl)propane, and 2,2-bis(4-((meth)acryloxypolyethoxypolypropoxy)phenyl)propane. Among them, from the viewpoint of further improving resolution and pattern formability, 2,2-bis(4-((meth)acryloxypolyethoxy)phenyl)propane is preferred.

[0055] Commercially available examples include 2,2-bis(4-((meth)acryloxydipropoxy)phenyl)propane, BPE-200 (Shin-Nakamura Chemical Co., Ltd.), and 2,2-bis(4-(methacryloxypentaethoxy)phenyl)propane, BPE-500 (Shin-Nakamura Chemical Co., Ltd.), and FA-321M (Showa Denko Materials Co., Ltd.).

[0056] Examples of nonylphenoxy polyethyleneoxyacrylates include nonylphenoxytetraethyleneoxyacrylate, nonylphenoxypentaethyleneoxyacrylate, nonylphenoxyhexaethyleneoxyacrylate, nonylphenoxyheptaethyleneoxyacrylate, nonylphenoxyoctaethyleneoxyacrylate, nonylphenoxynonaethyleneoxyacrylate, nonylphenoxydecaethyleneoxyacrylate, and nonylphenoxyundecaethyleneoxyacrylate.

[0057] (Photopolymerization initiator) The photopolymerization initiator (C) is not particularly limited as long as it is a component that can polymerize component (B), and can be appropriately selected from commonly used photopolymerization initiators. Component (C) can be used alone or in combination of two or more.

[0058] Examples of the component (C) include photopolymerization initiators such as acylphosphine oxides, oxime esters, aromatic ketones, quinones, alkylphenones, imidazoles, acridines, phenylglycines, and coumarins.

[0059] As the component (C), a hexaarylbiimidazole compound, an acridine compound, or an imidazole compound may be used in order to improve sensitivity and resolution in a well-balanced manner.

[0060] Examples of the hexaarylbiimidazole compound include 2-(o-chlorophenyl)-4,5-diphenylbiimidazole, 2,2',5-tris-(o-chlorophenyl)-4-(3,4-dimethoxyphenyl)-4',5'-diphenylbiimidazole, 2,4-bis-(o-chlorophenyl)-5-(3,4-dimethoxyphenyl)-diphenylbiimidazole, 2,4,5-tris-(o-chlorophenyl)-diphenylbiimidazole, 2-(o-chlorophenyl)-bis-4,5-(3,4-dimethoxyphenyl)-biimidazole, 2, Examples of suitable imidazoles include 2'-bis-(2-fluorophenyl)-4,4',5,5'-tetrakis-(3-methoxyphenyl)-biimidazole, 2,2'-bis-(2,3-difluoromethylphenyl)-4,4',5,5'-tetrakis-(3-methoxyphenyl)-biimidazole, 2,2'-bis-(2,4-difluorophenyl)-4,4',5,5'-tetrakis-(3-methoxyphenyl)-biimidazole, and 2,2'-bis-(2,5-difluorophenyl)-4,4',5,5'-tetrakis-(3-methoxyphenyl)-biimidazole. Among these, 2-(o-chlorophenyl)-4,5-diphenylimidazole dimer is preferred from the viewpoints of sensitivity and adhesion. As the 2-(o-chlorophenyl)-4,5-diphenylimidazole dimer, 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenyl-1,2-biimidazole is commercially available from Hodogaya Chemical Co., Ltd. under the trade name "B-CIM."

[0061] Examples of the acridine compound include 9-phenylacridine, 9-(p-methylphenyl)acridine, 9-(m-methylphenyl)acridine, 9-(p-chlorophenyl)acridine, 9-(m-chlorophenyl)acridine, 9-aminoacridine, 9-dimethylaminoacridine, 9-diethylaminoacridine, 9-pentylaminoacridine, 1,2-bis(9-acridinyl)ethane, 1,4-bis(9-acridinyl)butane, 1,6-bis(9-acridinyl)hexane, 1,8 ... bis(9-acridinyl)octane, 1,10-bis(9-acridinyl)decane, 1,12-bis(9-acridinyl)dodecane, 1,14-bis(9-acridinyl)tetradecane, 1,16-bis(9-acridinyl)hexadecane, 1,18-bis(9-acridinyl)octadecane, 1,20-bis(9-acridinyl)eicosane, 1,3-bis(9-acridinyl)-2-oxapropane, 1,3-bis(9-acridinyl)-2-thiapropane, and 1,5-bis(9-acridinyl)-3-thiapentane.

[0062] Examples of the imidazole compound include 2-(o-chlorophenyl)-4,5-diphenylbiimidazole, 2,2',5-tris-(o-chlorophenyl)-4-(3,4-dimethoxyphenyl)-4',5'-diphenylbiimidazole, 2,4-bis-(o-chlorophenyl)-5-(3,4-dimethoxyphenyl)-diphenylbiimidazole, 2,4,5-tris-(o-chlorophenyl)-diphenylbiimidazole, 2-(o-chlorophenyl)-bis-4,5-(3,4-dimethoxyphenyl)-biimidazole, 2,2'-bi bis-(2-fluorophenyl)-4,4',5,5'-tetrakis-(3-methoxyphenyl)-biimidazole, 2,2'-bis-(2,3-difluoromethylphenyl)-4,4',5,5'-tetrakis-(3-methoxyphenyl)-biimidazole, 2,2'-bis-(2,4-difluorophenyl)-4,4',5,5'-tetrakis-(3-methoxyphenyl)-biimidazole, and 2,2'-bis-(2,5-difluorophenyl)-4,4',5,5'-tetrakis-(3-methoxyphenyl)-biimidazole.

[0063] The amount of component (C) may be 0.1 to 10 parts by mass, 0.2 to 5 parts by mass, or 0.5 to 4 parts by mass, based on 100 parts by mass of the total amount of components (A) and (B). When the amount of component (C) is 0.1 part by mass or more, photosensitivity, resolution, and adhesion tend to be improved, while when it is 10 parts by mass or less, resist pattern formability tends to be better.

[0064] (sensitizer) The photosensitive resin composition according to this embodiment may further contain a sensitizer as component (D). By containing component (D), when exposed to light having a peak within a specific wavelength range, the photosensitive resin composition can have a maximum absorption near that specific wavelength range, thereby increasing the sensitivity of the photosensitive resin composition. The component (D) may be used alone or in combination of two or more.

[0065] Examples of component (D) include dialkylaminobenzophenone compounds, pyrazoline compounds, anthracene compounds, coumarin compounds, xanthone compounds, thioxanthone compounds, oxazole compounds, benzoxazole compounds, thiazole compounds, benzothiazole compounds, triazole compounds, stilbene compounds, triazine compounds, thiophene compounds, naphthalimide compounds, triarylamine compounds, and aminoacridine compounds. Component (D) may contain a pyrazoline compound or an anthracene compound to further improve resolution.

[0066] Examples of the pyrazoline compound include 1-(4-methoxyphenyl)-3-styryl-5-phenyl-pyrazoline, 1-phenyl-3-(4-methoxystyryl)-5-(4-methoxyphenyl)-pyrazoline, 1,5-bis-(4-methoxyphenyl)-3-(4-methoxystyryl)-pyrazoline, 1-(4-isopropylphenyl)-3-styryl-5-phenyl-pyrazoline, 1-phenyl-3-(4-isopropylstyryl)-5-(4-isopropylphenyl)-pyrazoline, 1,5-bis-(4-isopropylphenyl)-3-(4- 1-(4-tert-butyl-phenyl)-3-(4-isopropylstyryl)-pyrazoline, 1-(4-methoxyphenyl)-3-(4-tert-butyl-styryl)-5-(4-tert-butyl-phenyl)-pyrazoline, 1-(4-tert-butyl-phenyl)-3-(4-methoxystyryl)-5-(4-methoxyphenyl)-pyrazoline, 1-(4-isopropyl-phenyl)-3-(4-tert-butyl-styryl)-5-(4-tert-butyl-phenyl)-pyrazoline, 1-(4-tert-butyl-phenyl)-3-(4-isopropyl-styryl)-5-(4-isopropyl 1-phenyl-3-(4-isopropylstyryl)-5-(4-isopropylphenyl)-pyrazoline, 1-(4-isopropyl-phenyl)-3-(4-methoxystyryl)-5-(4-methoxyphenyl)-pyrazoline, 1-phenyl-3-(3,5-dimethoxystyryl)-5-(3,5-dimethoxyphenyl)-pyrazoline, 1-phenyl-3-(3,4-dimethoxystyryl)-5-(3,4-dimethoxyphenyl)-pyrazoline, 1-phenyl-3-(2,6-dimethoxystyryl)-5 -(2,6-dimethoxyphenyl)-pyrazoline, 1-phenyl-3-(2,5-dimethoxystyryl)-5-(2,5-dimethoxyphenyl)-pyrazoline, 1-phenyl-3-(2,3-dimethoxystyryl)-5-(2,3-dimethoxyphenyl)-pyrazoline, 1-phenyl-3-(2,4-dimethoxystyryl)-5-(2,4-dimethoxyphenyl)-pyrazoline, 1-(4-methoxyphenyl)-3-(3,5-dimethoxystyryl)-5-(3,5-dimethoxyphenyl)-pyrazoline, 1-(4-methoxyphenyl)-3-(3,4-dimethoxystyryl)-5-(3,4-dimethoxyphenyl)-pyrazoline, 1-(4-methoxyphenyl)-3-(2,6-dimethoxystyryl)-5-(2,6-dimethoxyphenyl)-pyrazoline, 1-(4-methoxyphenyl)-3-(2,5-dimethoxystyryl)-5-(2,5-dimethoxyphenyl)-pyrazoline, 1-(4-methoxyphenyl)-3-(2,3-dimethoxystyryl)-5-(2,3-dimethoxyphenyl)-pyrazoline, 1-(4-methoxyphenyl)-3-(2,4-dimethoxystyryl)-5-(2 ,4-dimethoxyphenyl)-pyrazoline, 1-(4-tert-butyl-phenyl)-3-(3,5-dimethoxystyryl)-5-(3,5-dimethoxyphenyl)-pyrazoline, 1-(4-tert-butyl-phenyl)-3-(3,4-dimethoxystyryl)-5-(3,4-dimethoxyphenyl)-pyrazoline, 1-(4-tert-butyl-phenyl)-3-(2,6-dimethoxystyryl)-5-(2,6-dimethoxyphenyl)-pyrazoline, 1-(4-tert-butyl-phenyl)-3-(2,5-dimethoxystyryl)-5 -(2,5-dimethoxyphenyl)-pyrazoline, 1-(4-tert-butyl-phenyl)-3-(2,3-dimethoxystyryl)-5-(2,3-dimethoxyphenyl)-pyrazoline, 1-(4-tert-butyl-phenyl)-3-(2,4-dimethoxystyryl)-5-(2,4-dimethoxyphenyl)-pyrazoline, 1-(4-isopropyl-phenyl)-3-(3,5-dimethoxystyryl)-5-(3,5-dimethoxyphenyl)-pyrazoline, 1-(4-isopropyl-phenyl)-3-(3,4-dimethoxystyryl)-5- (3,4-Dimethoxyphenyl)-pyrazoline, 1-(4-isopropyl-phenyl)-3-(2,6-dimethoxystyryl)-5-(2,6-dimethoxyphenyl)-pyrazoline, 1-(4-isopropyl-phenyl)-3-(2,5-dimethoxystyryl)-5-(2,5-dimethoxyphenyl)-pyrazoline, 1-(4-isopropyl-phenyl)-3-(2,3-dimethoxystyryl)-5-(2,3-dimethoxyphenyl)-pyrazoline, and 1-(4-isopropyl-phenyl)-3-(2,4-dimethoxystyryl)-5-(2,4-dimethoxyphenyl)-pyrazoline.

[0067] Examples of anthracene compounds include 9,10-dimethoxyanthracene, 9,10-diethoxyanthracene, 9,10-dipropoxyanthracene, 9,10-dibutoxyanthracene, and 9,10-dipentoxyanthracene.

[0068] From the viewpoint of improving photosensitivity and resolution, the content of component (D) may be 0.01 to 5 parts by mass, 0.01 to 1 part by mass, or 0.01 to 0.2 parts by mass relative to 100 parts by mass of the total amount of components (A) and (B).

[0069] (photochromic agent) The photosensitive resin composition may further contain a photocolor former as component (E) to enhance the sensitivity of the photosensitive resin composition. The photocolor former may be an amine-based compound. Examples of photocolor formers include tribromophenyl sulfone, leucocrystal violet, diphenylamine, benzylamine, triphenylamine, diethylaniline, and o-chloroaniline.

[0070] (Other ingredients) The photosensitive resin composition according to this embodiment may further contain, as necessary, additives such as dyes, thermal color-developing inhibitors, plasticizers, pigments, fillers, antifoaming agents, flame retardants, adhesion promoters, leveling agents, release promoters, antioxidants, fragrances, imaging agents, thermal crosslinking agents, polymerization inhibitors, etc. These additives may be used alone or in combination of two or more.

[0071] Dyes include, for example, malachite green, Victoria Pure Blue, brilliant green, and methyl violet. Plasticizers include, for example, p-toluenesulfonamide.

[0072] The photosensitive resin composition can be dissolved, as needed, in a solvent such as methanol, ethanol, acetone, methyl ethyl ketone, methyl cellosolve, ethyl cellosolve, toluene, N,N-dimethylformamide, propylene glycol monomethyl ether, or a mixed solvent thereof to prepare a solution with a solids content of about 30 to 60 mass %.

[0073] [Photosensitive element] The photosensitive element according to this embodiment includes a support and a photosensitive layer formed on the support, the photosensitive layer containing the photosensitive resin composition described above. When using the photosensitive element according to this embodiment, the photosensitive layer may be laminated on a substrate and then exposed without peeling off the support (support film). As shown in the schematic cross-sectional view of an example in FIG. 1, the photosensitive element 1 according to this embodiment includes a support 2 and a photosensitive layer 3 formed on the support 2 and derived from the photosensitive resin composition described above, and may also include other layers, such as a protective layer 4, if necessary.

[0074] Examples of the support include polyester films such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polyethylene-2,6-naphthalate (PEN), and polyolefin films such as polypropylene and polyethylene. Of these, PET film may be used because it is readily available and has excellent handleability (particularly heat resistance, heat shrinkage, and breaking strength) in the production process.

[0075] The haze of the support may be 0.01 to 1.0% or 0.01 to 0.5%. When the haze is 0.01% or more, the support itself tends to be easier to manufacture, while when it is 1.0% or less, micro-defects that may occur in the resist pattern tend to be reduced. "Haze" refers to cloudiness. In the present disclosure, haze refers to a value measured using a commercially available haze meter (turbidity meter) in accordance with the method specified in JIS K 7105. Haze can be measured, for example, using a commercially available turbidity meter such as the NDH-5000 (manufactured by Nippon Denshoku Industries Co., Ltd.).

[0076] The thickness of the support may be 1 to 100 μm, 5 to 60 μm, 10 to 50 μm, 10 to 40 μm, 10 to 30 μm, or 10 to 25 μm. When the thickness of the support is 1 μm or more, it tends to be possible to prevent the support from being broken when peeled off. Furthermore, when the thickness of the support is 100 μm or less, it is possible to prevent a decrease in resolution when exposure is performed through the support.

[0077] The photosensitive element may further include a protective layer, if necessary. As the protective layer, a film may be used in which the adhesive strength between the photosensitive layer and the protective layer is smaller than the adhesive strength between the photosensitive layer and the support, or a film with low fisheyes may be used. Specific examples include those that can be used as the support described above. From the viewpoint of releasability from the photosensitive layer, a polyethylene film may be used.

[0078] The thickness of the protective layer varies depending on the application, but may be 1 to 100 μm, 5 to 50 μm, 5 to 30 μm, or 15 to 30 μm. When the thickness of the protective layer is 1 μm or more, the protective layer tends to be less likely to be broken when peeled off, and when the thickness of the protective layer is 100 μm or less, the cost is likely to be excellent.

[0079] The photosensitive element can be produced, for example, as follows: A solution (coating liquid) of the photosensitive resin composition is applied to a support to form a coating layer, which is then dried to form a photosensitive layer. Next, the surface of the photosensitive layer opposite the support is covered with a protective layer to obtain a photosensitive element comprising the support, the photosensitive layer formed on the support, and the protective layer laminated on the photosensitive layer.

[0080] The coating solution can be applied to the support by a known method such as roll coating, comma coating, gravure coating, air knife coating, die coating, or bar coating.

[0081] The drying of the coating layer is not particularly limited as long as it can remove at least a portion of the organic solvent from the coating layer. For example, it may be performed at 70 to 150°C for about 5 to 30 minutes. After drying, the amount of solvent remaining in the photosensitive layer may be 2% by mass or less, from the viewpoint of preventing diffusion of the solvent in subsequent steps.

[0082] The thickness of the photosensitive layer in the photosensitive element can be appropriately selected depending on the application, but may be 1 to 100 μm, 5 to 50 μm, or 10 to 40 μm after drying. A thickness of 1 μm or more facilitates industrial coating and improves productivity. A thickness of 100 μm or less improves adhesion and resolution.

[0083] The photosensitive layer preferably has a transmittance of 5 to 75%, more preferably 7 to 60%, and even more preferably 10 to 40% for ultraviolet light with a wavelength of 365 nm. A transmittance of 5% or more facilitates improved adhesion, while a transmittance of 75% or less facilitates improved resolution. The transmittance can be measured using a UV spectrometer.

[0084] The form of the photosensitive element is not particularly limited. For example, it may be in the form of a sheet, or may be wound into a roll around a core. When wound into a roll, it may be wound with the support film on the outside. Examples of the core include plastics such as polyethylene resin, polypropylene resin, polystyrene resin, polyvinyl chloride resin, and ABS resin (acrylonitrile-butadiene-styrene copolymer).

[0085] An end separator may be provided on the end surface of the roll-shaped photosensitive element to protect the end surface, or a moisture-proof end separator may be provided to prevent edge fusion. The photosensitive element may be wrapped and packaged in a black sheet with low moisture permeability.

[0086] The photosensitive element can be suitably used, for example, in the method for forming a resist pattern described below. In particular, from the viewpoint of resolution, it is suitable for application to a manufacturing method for forming a conductor pattern by plating treatment.

[0087] [Method for forming resist pattern] The method for forming a resist pattern of this embodiment includes: (i) a step of forming a photosensitive layer on a substrate using the photosensitive resin composition or the photosensitive element (photosensitive layer forming step); (ii) a step of irradiating at least a portion (predetermined portion) of the photosensitive layer with actinic light to form a photocured portion (exposure step); and (iii) a step of removing at least a portion of the substrate other than the photocured portion to form a resist pattern (development step), and may include other steps as necessary. The resist pattern can also be referred to as a photocured product pattern of the photosensitive resin composition or a relief pattern. The method for forming a resist pattern can also be referred to as a method for producing a substrate with a resist pattern.

[0088] ((i) Photosensitive layer forming step) The photosensitive layer can be formed on the substrate by, for example, applying and drying the photosensitive resin composition, or by removing the protective layer from the photosensitive element and then heating and pressing the photosensitive layer of the photosensitive element onto the substrate. When a photosensitive element is used, a laminate is obtained, which is composed of a substrate, a photosensitive layer, and a support, which are stacked in this order. The substrate is not particularly limited, but is typically a circuit-forming substrate having an insulating layer and a conductor layer formed on the insulating layer, or a die pad (substrate for lead frame) such as an alloy substrate.

[0089] When a photosensitive element is used, the photosensitive layer forming step is preferably carried out under reduced pressure from the viewpoint of adhesion and followability. The photosensitive layer and / or the substrate may be heated at a temperature of 70 to 130°C during pressure bonding. The pressure bonding is carried out at a pressure of about 0.1 to 1.0 MPa (1 to 10 kgf / cm). 2The heating may be performed under a pressure of about 1000 psi (approximately 1000 psi), but these conditions are appropriately selected as needed. Note that if the photosensitive layer is heated to 70 to 130°C, it is not necessary to preheat the substrate in advance, but the substrate can also be preheated in order to further improve adhesion and conformability.

[0090] ((ii) Exposure process) In the exposure step, at least a part of the photosensitive layer formed on the substrate is irradiated with actinic rays, whereby the part irradiated with actinic rays is photocured to form a latent image. In this case, if a support is present on the photosensitive layer, and the support is transparent to actinic rays, the actinic rays can be irradiated through the support, but if the support is light-shielding, the support is removed before the photosensitive layer is irradiated with actinic rays.

[0091] Examples of the exposure method include a method of irradiating an actinic ray imagewise through a negative or positive mask pattern called artwork (mask exposure method). Other examples of the exposure method include a method of irradiating an actinic ray imagewise by a projection exposure method, and a method of irradiating an actinic ray imagewise by a direct writing exposure method such as an LDI (Laser Direct Imaging) exposure method or a DLP (Digital Light Processing) exposure method.

[0092] As the light source of the actinic rays, a known light source can be used, for example, a carbon arc lamp, a mercury vapor arc lamp, a high-pressure mercury lamp, a xenon lamp, a gas laser such as an argon laser, a solid-state laser such as a YAG laser, a semiconductor laser, etc., which effectively emit ultraviolet light and visible light, can be used.

[0093] ((iii) Development process) In the development step, at least a portion of the photosensitive layer other than the photocured portion is removed from the substrate, thereby forming a resist pattern on the substrate.

[0094] When a support is present on the photosensitive layer, the support is removed, and then the areas other than the photocured areas (which can also be called unexposed areas) are removed (developed). There are two development methods, wet development and dry development, but wet development is widely used.

[0095] In the case of wet development, development is carried out by a known development method using a developer suitable for the photosensitive resin composition. Examples of the development method include dipping, puddling, spraying, brushing, slapping, scrubbing, and swinging immersion. From the viewpoint of improving resolution, a high-pressure spray method may also be used. Development may also be carried out by combining two or more of these methods.

[0096] The composition of the developer is appropriately selected depending on the composition of the photosensitive resin composition. Examples of the developer include an alkaline aqueous solution and an organic solvent developer.

[0097] From the viewpoints of safety, stability, and ease of use, an alkaline aqueous solution may be used as the developer. Examples of bases for the alkaline aqueous solution include alkali hydroxides such as lithium, sodium, or potassium hydroxide; alkali carbonates such as carbonates or bicarbonates of lithium, sodium, potassium, or ammonium; alkali metal phosphates such as potassium phosphate and sodium phosphate; alkali metal pyrophosphates such as sodium pyrophosphate and potassium pyrophosphate; borax, sodium metasilicate, tetramethylammonium hydroxide, ethanolamine, ethylenediamine, diethylenetriamine, 2-amino-2-hydroxymethyl-1,3-propanediol, 1,3-diaminopropanol-2, and morpholine.

[0098] Examples of alkaline aqueous solutions that can be used include a dilute solution of 0.1 to 5% by mass of sodium carbonate, a dilute solution of 0.1 to 5% by mass of potassium carbonate, a dilute solution of 0.1 to 5% by mass of sodium hydroxide, and a dilute solution of 0.1 to 5% by mass of sodium tetraborate. The pH of the alkaline aqueous solution may be in the range of 9 to 14, and the temperature can be adjusted according to the alkaline developability of the photosensitive layer. The alkaline aqueous solution may contain, for example, a surfactant, an antifoaming agent, or a small amount of an organic solvent to promote development.

[0099] Examples of organic solvents used in alkaline aqueous solutions include acetone, ethyl acetate, alkoxyethanols having an alkoxy group having 1 to 4 carbon atoms, ethyl alcohol, isopropyl alcohol, butyl alcohol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, and diethylene glycol monobutyl ether.

[0100] Examples of organic solvents used in the organic solvent developer include 1,1,1-trichloroethane, N-methylpyrrolidone, N,N-dimethylformamide, cyclohexanone, methyl isobutyl ketone, γ-butyrolactone, etc. To prevent ignition, water may be added to these organic solvents in an amount of 1 to 20% by mass to form the organic solvent developer.

[0101] In the method for forming a resist pattern according to the present embodiment, after removing the uncured portion in the development step, the resist is heated at about 60 to 250°C or irradiated with 0.2 to 10 J / cm 2 as needed. 2 The method may further include a step of further hardening the resist pattern by exposing the resist pattern to light.

[0102] [Wiring pattern formation method] The method for forming a wiring pattern according to this embodiment includes a step of etching or plating a substrate on which a resist pattern has been formed by the method for forming a resist pattern described above, and may further include a step of removing the photocured portion with an alkaline aqueous solution after the etching or plating.

[0103] In the plating process, a conductive layer provided on a substrate is plated using a resist pattern formed on the substrate as a mask. After the plating process, the resist may be removed by removing the resist pattern as described below, and the conductive layer covered by the resist may be etched to form a conductive pattern. The plating method may be electrolytic plating or electroless plating, or may be electroless plating.

[0104] In the etching process, a resist pattern formed on a substrate is used as a mask to etch away the conductive layer provided on the substrate, thereby forming a conductive pattern. The etching method is appropriately selected depending on the conductive layer to be removed. Examples of etching solutions include cupric chloride solution, ferric chloride solution, alkaline etching solution, and hydrogen peroxide-based etching solution.

[0105] After the etching or plating process, the resist pattern on the substrate may be removed. The resist pattern can be removed, for example, with an aqueous solution that is stronger than the aqueous alkaline solution used in the development process. Examples of the strong alkaline aqueous solution include a 1 to 10% by mass aqueous solution of sodium hydroxide and a 1 to 10% by mass aqueous solution of potassium hydroxide. The resist pattern may be removed using a strong alkaline aqueous solution at 45 to 65°C.

[0106] When the resist pattern is removed after plating, the conductor layer covered with the resist is further etched by etching to form a conductor pattern, thereby manufacturing a desired printed wiring board. The etching method used here is appropriately selected depending on the conductor layer to be removed. For example, the above-mentioned etching solution can be used.

[0107] The method for forming a wiring pattern according to this embodiment can be applied to the manufacture of not only single-layer printed wiring boards but also multi-layer printed wiring boards, and can also be applied to the manufacture of printed wiring boards having small-diameter through holes. [Example]

[0108] The present disclosure will be specifically described below based on examples, but the present disclosure is not limited thereto.

[0109] (Synthesis Example 1) Butylamine (23.8 g, 0.325 mol) and dehydrated toluene (400 mL) were added to a flask equipped with a magnetic rotor, reflux condenser, calcium chloride tube, thermometer, and dropping funnel, and the mixture was cooled to 0 to 5°C. 2-isocyanatoethyl methacrylate (50.4 g, 0.325 mol) was then slowly added dropwise to the flask, followed by stirring at room temperature for 6 hours to obtain a reaction solution. The precipitate formed in the reaction solution was collected by filtration, and the filtrate was concentrated under reduced pressure. The precipitate and the concentrate were combined to obtain Monomer U (yield 100%). Monomer U is a compound with a urea bond formed by the reaction of the isocyanate group of 2-isocyanatoethyl methacrylate with the amino group of butylamine.

[0110] [Polymer] Examples 1 to 4 A flask equipped with a stirrer, reflux condenser, thermometer, dropping funnel, and nitrogen inlet tube was charged with the amounts (g) of styrene, benzyl methacrylate, methacrylic acid, monomer U, methyl cellosolve, and toluene shown in Table 1, and the mixture was heated to 70°C while stirring under a nitrogen atmosphere. A mixture of azobisisobutyronitrile (AIBN), methyl cellosolve, and toluene was added dropwise to the flask over 30 minutes, and the reaction was carried out with stirring at 75°C for 90 minutes, 85°C for 2 hours, and 95°C for 2 hours. The reaction solution was then cooled to room temperature. The toluene was removed from the reaction solution by distillation under reduced pressure, and the residue was poured into water. The precipitate was collected and dried to obtain polymers A1 to A4.

[0111] (Comparative Example 1) Polymer A5 was obtained in the same manner as in Examples 1 to 4, except that styrene, benzyl methacrylate, methacrylic acid, AIBN, methyl cellosolve, and toluene in the amounts (g) shown in Table 1 were used.

[0112] The Mw of the polymer was measured by gel permeation chromatography (GPC) and calculated using a calibration curve of standard polystyrene. The calibration curve was approximated by a cubic equation of the universal calibration curve according to JIS K 7252-2 (2016) using a set of five standard polystyrene samples (PStQuick MP-H, PStQuick B [product name, manufactured by Tosoh Corporation]). The GPC conditions are shown below.

[0113] (GPC conditions) Pump, detector: HLC-8320 (Tosoh Corporation) Column: TSKgel SuperMultipore HZ-M (3 columns) (Tosoh Corporation) Eluent: tetrahydrofuran (THF) Measurement temperature: 40℃ Flow rate: 0.35mL / min

[0114] [Table 1]

[0115] [Photosensitive resin composition] Photosensitive resin compositions were prepared by mixing 60 parts by mass of the polymer with the components in the amounts (parts by mass) shown in Table 2.

[0116] Details of each component shown in Table 2 are as follows: (Photopolymerizable compound) B-1: EO-modified bisphenol A dimethacrylate (manufactured by Showa Denko Materials Co., Ltd., product name: FA-321M) B-2: EO-modified polypropylene glycol dimethacrylate (manufactured by Showa Denko Materials Co., Ltd., product name: FA-023M) (Photopolymerization initiator) C-1: 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenylbiimidazole (manufactured by Hodogaya Chemical Co., Ltd., trade name: B-CIM) (sensitizer) D-1: 9,10-dibutoxyanthracene (Kawasaki Chemical Industries, Ltd.) (photochromic agent) E-1: 4,4',4''-methylidynetris(N,N-dimethylaniline) (dye) F-1: 4-[(4-dimethylaminophenyl)-phenyl-methyl]-N,N-dimethyl-aniline

[0117] [Table 2]

[0118] [Photosensitive element] The photosensitive resin composition was applied to a 16 μm-thick PET film (Teijin Film Solutions Limited, product name "G2J") (support) and dried for 2 minutes in a hot air convection dryer at 80°C and 120°C, respectively, to form a photosensitive layer with a dry thickness of 35 μm. A polypropylene film (Tamapoly Corporation, product name "NF-13") (protective layer) was laminated onto this photosensitive layer, yielding a photosensitive element in which the support, photosensitive layer, and protective layer were laminated in this order.

[0119] [evaluation] The photosensitive element was subjected to the following evaluations, and the results are shown in Table 3.

[0120] (stickiness) After the photosensitive element was heated to 30° C., the protective film was removed and the surface of the photosensitive layer was checked for stickiness.

[0121] (elastic modulus) The photosensitive layer of the photosensitive element was laminated four times at 80°C under a pressure of 0.4 MPa to prepare a photosensitive film. The photosensitive film was sandwiched between the measuring plates of a rheometer (manufactured by TA Instruments Co., Ltd.), and the storage modulus at 30°C and 110°C was measured.

[0122] (Solubility) The photosensitive layer of the photosensitive element was laminated on a silicon substrate at 110° C. under a pressure of 0.4 MPa, and then immersed in a 1% by mass aqueous solution of sodium carbonate at 25° C. to measure the time it took for the photosensitive layer to completely dissolve.

[0123] (Laminate) A copper-clad laminate (product name MCL-E-67, manufactured by Showa Denko Materials Co., Ltd.) was prepared by laminating copper foil (35 mm thick) on both sides of a glass fiber-reinforced epoxy resin layer. A photoresist pattern with a line width / space width of 100 μm / 100 μm was formed on one copper surface of the copper-clad laminate, and then the laminate was immersed in an etching solution. The photoresist was then removed, and grooves with a width of 100 μm, a spacing of 100 μm, and a depth of 15 μm were formed in the copper-clad laminate.

[0124] The photosensitive element was laminated on the copper surface of the copper-clad laminate, on the grooved side of the copper-clad laminate. The lamination was carried out using a heat roll at 110°C, with a pressure of 0.4 MPa and a roll speed of 1.0 m / min, while removing the protective layer. In this way, a laminate was obtained in which the copper-clad laminate, the photosensitive layer, and the support were laminated in this order.

[0125] (Following ability) Using an ultraviolet exposure machine (manufactured by Mikasa Co., Ltd., product name: MA-20) equipped with a photomask on which a rectangular pattern with a line width / space width of 100 μm / 100 μm was formed, the laminate was exposed to 10 mJ / cm on the support surface of the laminate, with the photomask pattern and groove direction perpendicular to each other. 2 The illuminance was measured using an ultraviolet illuminance meter (manufactured by Ushio Inc., product name: UIT-150) equipped with a 365 nm compatible probe. After exposure, the support was peeled off, and the unexposed portions were removed by spraying a 1% by mass aqueous solution of sodium carbonate at 30°C for 90 seconds onto the photosensitive layer (development treatment).

[0126] After the development process, the presence or absence of voids formed between the photosensitive layer and the grooves of the copper-clad laminate was observed using a scanning electron microscope SU5000 manufactured by Hitachi High-Technologies Corporation. Figure 2 shows an electron microscope photograph of the resist pattern formed in Example 5, and Figure 3 shows an electron microscope photograph of the resist pattern formed in Comparative Example 2.

[0127] [Table 3]

[0128] From the above results, it can be confirmed that by using the polymers and photosensitive resin compositions of the examples, a photosensitive layer can be formed that is not sticky on the layer surface at around 30°C, exhibits fluidity at 110°C, and is free of lamination voids. [Explanation of symbols]

[0129] 1...photosensitive element, 2...support, 3...photosensitive layer, 4...protective layer.

Claims

1. A polymer comprising a structural unit represented by the following formula (I), a structural unit having a carboxy group, and a structural unit based on styrene or a styrene derivative: the content of the structural unit represented by formula (I) is 5 to 50 mass% based on the total amount of the polymer, A polymer having a weight average molecular weight of 5,000 or more and 30,000 or less. 【Chemistry 1】 [In formula (I), R １ represents a hydrogen atom or a methyl group, M represents an alkylene group or an alkylene oxide chain, R ２ represents an alkyl group or an aryl group.

2. A polymer described in claim 1, wherein the content of structural units based on styrene or a styrene derivative is 10 to 60 mass % based on the total amount of the polymer.

3. A photosensitive resin composition comprising a binder resin containing the polymer according to claim 1 or 2, a photopolymerizable compound, and a photopolymerization initiator.

4. The photosensitive resin composition according to claim 3 , wherein the photopolymerization initiator comprises a hexaarylbiimidazole compound.

5. A photosensitive resin composition described in claim 3 or 4, wherein the photopolymerizable compound includes alkylene oxide-modified bisphenol A di(meth)acrylate.

6. The photosensitive resin composition according to any one of claims 3 to 5, further comprising a sensitizer.

7. The photosensitive resin composition according to any one of claims 3 to 6, further comprising a photocolor former.

8. A support film and a photosensitive layer formed on the support film, A photosensitive element, wherein the photosensitive layer comprises the photosensitive resin composition according to any one of claims 3 to 7.

9. forming a photosensitive layer on a substrate using the photosensitive resin composition according to any one of claims 3 to 7 or the photosensitive element according to claim 8; a step of irradiating at least a portion of the photosensitive layer with actinic rays to form a photocured portion; removing at least a portion of the photosensitive layer other than the photocured portion from the substrate to form a resist pattern; A method for forming a resist pattern comprising:

10. A method for forming a wiring pattern, comprising the step of etching or plating a substrate on which a resist pattern has been formed by the method for forming a resist pattern according to claim 9 to form a conductor pattern.

11. The method for forming a wiring pattern according to claim 10 , further comprising the step of removing the photocured portion with an alkaline aqueous solution after the etching treatment or the plating treatment.

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