Photosensitive resin composition, photosensitive element, method for forming a resist pattern, method for forming a wiring pattern, and polymer

Abstract

To provide a photosensitive resin composition that exhibits excellent resolution, adhesion, and storage stability. [Solution] A photosensitive resin composition comprising a binder resin containing a polymer comprising a structural unit represented by the following formula (I) and a structural unit having a carboxyl group, a photopolymerizable compound, and a photopolymerization initiator. TIFF2026085647000011.tif34149 [In formula (I), R 1 R represents a hydrogen atom or a methyl group. 2 This represents an alkyl group having a chain-like structure in which four or more carbon atoms are continuously linked by single bonds from an adjacent nitrogen atom, and having a total of five or more carbon atoms.

Description

[Technical Field]

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

[0002] In the field of printed circuit board manufacturing, photosensitive elements (laminated structures) comprising a photosensitive resin composition and a layer formed on a support film using the photosensitive resin composition (hereinafter also referred to as the "photosensitive layer") are widely used as resist materials for etching or plating processes.

[0003] Printed circuit boards are manufactured using the above-mentioned photosensitive element by, for example, the following procedure. 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 photocurable area. At this time, the support film is peeled off before or after exposure. After that, the area of ​​the photosensitive layer other than the photocurable area is removed with a developer to form a resist pattern. Next, the resist pattern is used as a resist and subjected to etching or plating to form a conductor pattern, and finally the photocurable area (resist pattern) of the photosensitive layer is peeled off (removed).

[0004] Patent documents 1 and 2 disclose photosensitive resin compositions that have excellent high resolution as resist materials. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2005-122123 [Patent Document 2] Japanese Patent Publication No. 2006-234995 [Overview of the project] [Problems that the invention aims to solve]

[0006] However, conventional photosensitive resin compositions are not sufficient in terms of adhesion and still have room for improvement. Furthermore, conventional photosensitive resin compositions may experience edge fusion, where the resin seeps out during storage, and there is room for improvement in terms of storage stability as well.

[0007] Therefore, the main objective of this disclosure is to provide a photosensitive resin composition that is excellent in resolution, adhesion, and storage stability. [Means for solving the problem]

[0008] This disclosure includes the following [1] to

[14] . [1] A binder resin comprising a polymer containing structural units represented by the following formula (I) and structural units having a carboxyl group, Photopolymerizable compounds, Photopolymerization initiator, A photosensitive resin composition containing [a specific substance]. [ka] [In formula (I), R 1 R represents a hydrogen atom or a methyl group. 2 This represents an alkyl group having a chain-like structure in which four or more carbon atoms are continuously linked by single bonds from an adjacent nitrogen atom, and having a total of five or more carbon atoms. [2] The photosensitive resin composition according to [1], wherein the content of the structural unit represented by formula (I) is 5 to 50% by mass based on the total amount of the polymer. [3] The photosensitive resin composition according to [1] or [2], wherein the photopolymerization initiator comprises a hexaarylbiimidazole compound. [4] A photosensitive resin composition according to any one of [1] to [3], further comprising a sensitizer. [5] A photosensitive resin composition according to any one of [1] to [4], further comprising a photochromic agent. [6] comprising a support film and a photosensitive layer formed on the support film, A photosensitive element, wherein the photosensitive layer contains the photosensitive resin composition according to any one of [1] to [5]. [7] A step of forming a photosensitive layer on a substrate using the photosensitive resin composition according to any one of [1] to [5]; A step of irradiating at least a part of the photosensitive layer with actinic rays to form a photocured part; A step of removing at least a part other than the photocured part of the photosensitive layer from the substrate to form a resist pattern; A method for forming a resist pattern, comprising: [8] A step of forming a photosensitive layer on a substrate using the photosensitive element according to [6]; A step of irradiating at least a part of the photosensitive layer with actinic rays to form a photocured part; A step of removing at least a part other than the photocured part of the photosensitive layer from the substrate to form a resist pattern; A method for forming a resist pattern, comprising: [9] A method for forming a wiring pattern, comprising a step of forming a conductor pattern by subjecting a substrate on which a resist pattern has been formed by the method for forming a resist pattern according to [7] to an etching treatment or a plating treatment.

[10] A method for forming a wiring pattern, comprising a step of forming a conductor pattern by subjecting a substrate on which a resist pattern has been formed by the method for forming a resist pattern according to [8] to an etching treatment or a plating treatment.

[11] The method for forming a wiring pattern according to [9], further comprising a step of removing the photocured part with an alkaline aqueous solution after the etching treatment or the plating treatment.

[12] The method for forming a wiring pattern according to

[10] , further comprising a step of removing the photocured part with an alkaline aqueous solution after the etching treatment or the plating treatment.

[13] A polymer containing a structural unit represented by the following formula (I) and a structural unit having a carboxy group.

Chemical formula

[14] The polymer according to

[13] , wherein the content of the structural unit represented by formula (I) is 5 to 50% by mass based on the total amount of the polymer. [Effects of the Invention]

[0009] According to this disclosure, it is possible to provide a photosensitive resin composition, a photosensitive element, a method for forming a resist pattern, and a method for forming a wiring pattern that are excellent in resolution, adhesion, and storage stability. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 is a schematic cross-sectional view showing one embodiment of a photosensitive element. [Modes for carrying out the invention]

[0011] The embodiments of this disclosure will be described in detail below. However, this disclosure is not limited to the embodiments described below.

[0012] In this specification, the term "process" includes not only independent processes but also processes that are indistinguishable from other processes as long as their intended function is achieved. Numerical ranges indicated using "~" include the minimum and maximum values ​​of the numbers before and after "~", respectively. The term "layer" includes not only structures formed over the entire surface when observed in a plan view, but also structures formed in only a portion of it. "(meth)acrylic acid" means at least one of "acrylic acid" or its corresponding "methacrylic acid." The same applies to other similar expressions such as (meth)acrylate and (meth)acryloyl.

[0013] In this specification, the amount of each component in the photosensitive resin composition means the total amount of multiple substances present in the photosensitive resin composition, unless otherwise specified, if there are multiple substances corresponding to each component. In the numerical ranges described in this specification, the upper or lower limits of the numerical range may be replaced with the values ​​shown in the examples. Embodiments that combine the matters described in this specification as arbitrarily are also included in this disclosure. In this specification, "solids" refers to the non-volatile content of the photosensitive resin composition excluding volatile substances such as water and solvents. That is, "solids" refers to components other than solvents that remain without volatilizing during the drying of the photosensitive resin composition described later, and includes components that are liquid, syrup-like, and waxy at room temperature (25°C).

[0014] [polymer] The polymer according to this embodiment includes a structural unit represented by the following formula (I) and a structural unit having a carboxyl group.

[0015] [ka]

[0016] In formula (I), R 1 R represents a hydrogen atom or a methyl group. 2 This represents an alkyl group having a chain-like structure in which four or more carbon atoms are continuously linked by single bonds from an adjacent nitrogen atom, and having a total number of carbon atoms of five or more.

[0017] Here, we will explain alkyl groups that have a chain-like structure in which four or more carbon atoms are continuously linked by single bonds from an adjacent nitrogen atom, and have a total of five or more carbon atoms, using specific examples.

[0018] [ka]

[0019] The group represented by formula (2A) is a 1,1,3,3 - tetramethylbutyl (tert - octyl) group. * represents the bonding position with the adjacent nitrogen atom, and the group represented by formula (2A) has a chain structure (main chain) in which 4 carbon atoms are continuously connected by single bonds from *. Since the group represented by formula (2A) has a predetermined chain structure and the total number of carbon atoms is 8, R 2 is included in the alkyl group represented by

[0020] The group represented by formula (2B) is a 1,1 - dimethyl - 3 - oxobutyl group. * represents the bonding position with the adjacent nitrogen atom, and the group represented by formula (2B) has a chain structure (main chain) in which 4 carbon atoms are continuously connected by single bonds from *. Since the group represented by formula (2B) has a predetermined chain structure and the total number of carbon atoms is 6, R 2 is included in the alkyl group represented by

[0021] The group represented by formula (2C) is an n - dodecyl group. * represents the bonding position with the adjacent nitrogen atom, and the group represented by formula (2C) has a chain structure (main chain) in which 12 carbon atoms are continuously connected by single bonds from *. Since the group represented by formula (2C) has a predetermined chain structure and the total number of carbon atoms is 12, R 2 is included in the alkyl group represented by​​​​​​​​​​2 It is not included in the alkyl group represented by .

[0024] R 2 The number of consecutive carbon atoms constituting the chain structure of the alkyl group represented by may be, for example, 20 or less, 15 or less, or 12 or less.

[0025] The chain structure is not particularly limited as long as four or more carbon atoms are continuously linked by single bonds from an adjacent nitrogen atom. The chain structure may be, for example, a chain structure in which four or more groups are linked together, at least one of which is selected from the group consisting of divalent groups represented by the following formulas (Ia), (Ib), (Ic), and (Id) (except for chain structures in which the divalent group represented by formula (Id) is bonded to an adjacent nitrogen atom). The chain structure may consist of one of the divalent groups represented by formulas (Ia), (Ib), (Ic), and (Id) alone, or it may consist of a combination of two or more.

[0026] [ka]

[0027] In equation (Ia), * indicates the joining position. In equation (Ib), R b1 R represents an alkyl group having 1 to 4 carbon atoms, and * represents the bond position. In formula (Ic), R c1 and R c2 Each of these independently represents an alkyl group with 1 to 4 carbon atoms, and * represents the bond position.

[0028] R b1 , R c1 , and R c2 The alkyl group represented may be, for example, a methyl group, an ethyl group, a propyl group, or a butyl group.

[0029] R 2 The total number of carbon atoms in the alkyl group represented by may be, for example, 6 or more, and may be 20 or less, 15 or less, or 12 or less.

[0030] R 2 Specific examples of alkyl groups represented by include n-hexyl group, n-octyl group, n-decyl group, n-dodecyl group, 1,1,3,3-tetramethylbutyl (tert-octyl) group, 2-ethylhexyl group, and 1,1-dimethyl-3-oxobutyl group.

[0031] Examples of monomers that give rise to the structural unit represented by formula (II) include N-(1,1,3,3-tetramethylbutyl)(meth)acrylamide (N-tert-octyl(meth)acrylamide), N-(1,1-dimethyl-3-oxobutyl)(meth)acrylamide (diacetone(meth)acrylamide), and Nn-dodecyl(meth)acrylamide.

[0032] The polymer according to this embodiment, by containing the structural unit represented by formula (I), can improve adhesion and storage stability while maintaining resolution when used as a photosensitive resin composition. This effect is due to the pseudo-high molecular weight formation that occurs through intermolecular interactions via hydrogen bonds, and R 2 The inventors believe that this is because the Tg (glass transition temperature) can be controlled by an alkyl group having a predetermined structure.

[0033] Furthermore, the polymer according to this embodiment can control its viscosity by utilizing the interaction between amide groups through hydrogen bonding, and therefore tends to exhibit excellent conformability.

[0034] The content of the structural unit represented by formula (I) in the polymer may be 5 to 50% by mass, based on the total amount of polymer. The content of the structural unit represented by formula (I) may be 6% or more by mass, 7% or more by mass, or 8% or more by mass, from the viewpoint of further improving resolution, adhesion, and storage stability. The content of the structural unit represented by formula (I) may be 45% or less by mass, 40% or less by mass, 35% or less by mass, 30% or less by mass, 25% or less by mass, or 20% or less by mass, from the viewpoint of increasing the solubility of the polymer in alkaline aqueous solutions.

[0035] The polymer according to this embodiment contains structural units having carboxyl groups from the viewpoint of alkali developability. The content of structural units having carboxyl groups may be 10 to 45% by mass, 15 to 40% by mass, or 20 to 35% by mass, based on the total amount of polymer, in order to improve alkali developability in a balanced manner. When the content of structural units having carboxyl groups is 10% by mass or more, alkali developability tends to be further improved, and when it is 45% by mass or less, alkali resistance tends to be superior.

[0036] Examples of monomers that provide structural units having a carboxyl 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, monomethyl maleate, monoethyl maleate, monoisopropyl maleate, fumaric acid, cinnamic acid, α-cyanocinnamic acid, itaconic acid, crotonic acid, and propiolic acid. The polymer according to this embodiment may contain structural units derived from (meth)acrylic acid in order to further improve alkali developability.

[0037] The polymer according to this embodiment may further contain structural units derived from styrene or styrene derivatives from the viewpoint of adhesion and peelability. Styrene derivatives are polymerizable compounds in which a hydrogen atom at the α-position or aromatic ring of styrene is substituted. Examples of styrene derivatives include vinyltoluene, α-methylstyrene, p-methylstyrene, and p-ethylstyrene.

[0038] The content of structural units derived from styrene or styrene derivatives in the polymer may be 20-60% by mass, 25-55% by mass, or 30-50% by mass, based on the total amount of polymer. When the content of structural units derived from styrene or styrene derivatives is 20% by mass or more, adhesion tends to improve, and when it is 60% by mass or less, the size of the peeling fragments during development can be suppressed, and the time required for peeling tends to be reduced.

[0039] The polymer according to this embodiment may further contain structural units derived from benzyl (meth)acrylate or a benzyl (meth)acrylate derivative, from the viewpoint of resolution and aspect ratio. Examples of benzyl (meth)acrylate derivatives include 4-methylbenzyl (meth)acrylate. From the viewpoint of improving resolution, the content of structural units derived from benzyl (meth)acrylate or a benzyl (meth)acrylate derivative in the polymer may be 5 to 40% by mass, 8 to 30% by mass, or 10 to 25% by mass, based on the total amount of the polymer.

[0040] The polymer according to this embodiment may further contain structural units derived from alkyl (meth)acrylates from the viewpoint of improving plasticity. Examples of alkyl (meth)acrylates include methyl (meth)acrylate, 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.

[0041] The weight-average molecular weight (Mw) of the polymer may be 5000 or more, 8000 or more, 10000 or more, 12000 or more, or 15000 or more, from the viewpoint of improving resolution. The Mw of the polymer may be 60000 or less, 55000 or less, 50000 or less, 45000 or less, or 40000 or less, from the viewpoint of superior developability. Mw can be measured using a calibration curve of standard polystyrene by gel permeation chromatography (GPC).

[0042] Polymers can be obtained, for example, by polymerizing monomers by radical polymerization using solution polymerization. More specifically, they can be obtained by polymerizing monomers containing a monomer that gives a structural unit represented by formula (I) and a monomer that gives a structural unit having a carboxyl group in a solvent.

[0043] The solvent can be any organic solvent commonly used in the field of radical polymerization. Examples of solvents include aromatic hydrocarbons such as toluene, xylene, and benzene; aliphatic hydrocarbons such as hexane and heptane; alicyclic hydrocarbons such as cyclohexane and methylcyclohexane; ketones such as methyl ethyl ketone and methyl isobutyl ketone; alcohols or glycols such as ethylene glycol, propylene glycol, and dipropylene glycol; glycol ethers such as methyl cellosolve, 2-butoxyethanol, propylene glycol monomethyl ether, and dipropylene glycol monomethyl ether; and glycol esters such as ethylene glycol diacetate and propylene glycol monomethyl ether acetate. The amount of solvent used can be appropriately determined depending on the type of monomer, reaction conditions, solid content concentration, etc.

[0044] When polymerizing monomers, a chain transfer agent may be added as needed. Examples of chain transfer agents include monofunctional thiol compounds such as n-dodecyl mercaptan and β-mercaptopropionic acid; difunctional thiol compounds such as polysiloxanes with mercapto-modified ends; and polyfunctional polysiloxanes with mercapto-modified side chains. The amount of chain transfer agent can be appropriately set according to the type of monomer, reaction conditions, etc., and is not particularly limited, but may be 0.01 to 3% by mass relative to the total amount of monomers.

[0045] When polymerizing monomers, a thermal radical generator may be added as needed. Examples of thermal radical generators include 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). The amount of thermal radical generator can be appropriately set according to the type of monomer, reaction conditions, etc., and is not particularly limited, but may be 0.01% by mass or more, 0.05% by mass or more, 10% by mass or less, 5% by mass or less, or 1% by mass or less, relative to the total amount of monomers.

[0046] The polymerization temperature may be 60-100°C or 70-100°C. The polymerization time may be 1-15 hours or 5-10 hours.

[0047] (A) Component: Binder resin Component (A) includes a polymer having the above-described specific structure (hereinafter sometimes referred to as "component (A1)"). By including component (A1) in component (A), the adhesion and storage stability of the photosensitive resin composition (photosensitive layer) can be improved while maintaining its resolution. Component (A1) may consist of only one type of resin, or it may consist of two or more types of resins.

[0048] Component (A) may further contain resins other than component (A1). Examples of such resins include alkali-soluble resins having phenolic hydroxyl groups. Examples of resins having phenolic hydroxyl groups include polyhydroxystyrene; hydroxystyrene-based resins such as copolymers containing hydroxystyrene as a monomer unit; phenolic resins; polybenzoxazole precursors such as poly(hydroxyamide); poly(hydroxyphenylene) ethers; and polynaphthol.

[0049] 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 per 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 photo-cured portion of the photosensitive layer tends to be better.

[0050] (B) Component: Photopolymerizable compound 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, nadiimide 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 functional group exhibiting photopolymerization may be a (meth)acryloyl group. Component (B) may be used alone or in combination of two or more.

[0051] Examples of photopolymerizable compounds having one ethylenically unsaturated group include (meth)acrylic acid, alkyl (meth)acrylate esters, and phthalic acid compounds.

[0052] Examples of alkyl (meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and hydroxyethyl (meth)acrylate.

[0053] Component (B) may contain a phthalate compound from the viewpoint of suitably improving resolution, adhesion, and resist shape. Examples of phthalate compounds include 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.

[0054] 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.

[0055] Component (B) may contain alkylene oxide-modified bisphenol A di(meth)acrylate from the viewpoint of improving alkaline developability and resolution. Examples of alkylene oxide-modified bisphenol A di(meth)acrylate include 2,2-bis(4-((meth)acryloxypolyethoxy)phenyl)propane(EO-modified bisphenol A dimethacrylate), 2,2-bis(4-((meth)acryloxypolypropoxy)phenyl)propane(PO-modified bisphenol A dimethacrylate), 2,2-bis(4-((meth)acryloxypolybutoxy)phenyl)propane(BO-modified bisphenol A dimethacrylate), and 2,2-bis(4-((meth)acryloxypolyethoxypolypropoxy)phenyl)propane(EO,PO-modified bisphenol A dimethacrylate).

[0056] In this specification, "EO-modified" means having a block structure of ethylene oxide (EO) groups, "PO-modified" means having a block structure of propylene oxide (PO) groups, and "BO-modified" means having a block structure of butylene oxide (BO) groups.

[0057] Examples of photopolymerizable compounds having three or more ethylenically unsaturated groups include (meth)acrylates having a trimethylolpropane-derived skeleton such as trimethylolpropane tri(meth)acrylate; (meth)acrylates having a tetramethylolmethane-derived skeleton such as tetramethylolmethane tri(meth)acrylate and tetramethylolmethane tetra(meth)acrylate; (meth)acrylates having a pentaerythritol-derived skeleton such as pentaerythritol tri(meth)acrylate and pentaerythritol tetra(meth)acrylate; (meth)acrylates having a dipentaerythritol-derived skeleton such as dipentaerythritol penta(meth)acrylate and dipentaerythritol hexa(meth)acrylate; (meth)acrylates having a ditrimethylolpropane-derived skeleton such as ditrimethylolpropane tetra(meth)acrylate; and (meth)acrylates having a diglycerin-derived skeleton. Among these, from the viewpoint of improving chemical resistance after curing (exposure) and increasing the difference in developer resistance between the exposed and unexposed areas, the photopolymerizable compound having three or more ethylenically unsaturated groups may be a (meth)acrylate compound having a skeleton derived from dipentaerythritol, or it may be dipentaerythritol penta(meth)acrylate.

[0058] From the viewpoint of improving the alkali developability of the unexposed portion of the photosensitive resin composition and improving the adhesive strength of the exposed portion, component (B) may contain a photopolymerizable compound having an ethylenically unsaturated group and an acid-modified group. Examples of the acidic group to be modified include a carboxyl group, a sulfo group, and a phenolic hydroxyl group. Among these, the acidic group to be modified may be a carboxyl group.

[0059] Examples of photopolymerizable compounds having ethylenically unsaturated groups and acidic groups include styrene-maleic acid resins and acid-modified vinyl group-containing epoxy derivatives.

[0060] Styrene-maleic acid resins are hydroxyethyl (meth)acrylate-modified products of styrene-maleic anhydride copolymers. Acid-modified vinyl group-containing epoxy derivatives are compounds 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.

[0061] The epoxy resin is not particularly limited as long as it is a compound having two or more epoxy groups. Examples of epoxy resins include glycidyl ether type epoxy resins, glycidylamine type epoxy resins, and glycidyl ester type epoxy resins. Among these, the epoxy resin may be a bisphenol novolac type epoxy resin or a bisphenol F novolac type epoxy resin from the viewpoint of reliability when mounted on semiconductor chips.

[0062] The vinyl group-containing organic acid is not particularly limited and may be a vinyl group-containing monocarboxylic acid. Examples of vinyl group-containing monocarboxylic acids include acrylic acid derivatives such as acrylic acid, acrylic acid dimers, methacrylic acid, β-furfurylacrylic acid, β-styrylacrylic acid, cinnamic acid, crotonic acid, and α-cyanocinnamic acid; semi-ester compounds which are reaction products of hydroxyl group-containing acrylates and dibasic acid anhydrides; and semi-ester compounds which are reaction products of vinyl group-containing monoglycidyl ethers or vinyl group-containing monoglycidyl esters and dibasic acid anhydrides.

[0063] Examples of photopolymerizable compounds having an α,β-unsaturated carbonyl group include α,β-unsaturated carboxylic acid esters of polyhydric alcohols, (meth)acrylates having a urethane bond, bisphenol-type (meth)acrylates, nonylphenoxypolyethylene oxyacrylates, α,β-unsaturated carboxylic acid adducts of glycidyl group-containing compounds, and alkyl (meth)acrylates.

[0064] Examples of α,β-unsaturated carboxylic acid esters of polyhydric alcohols 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.

[0065] Component (B) may contain polyalkylene glycol di(meth)acrylate from the viewpoint of improving the flexibility of the resist pattern. The polyalkylene glycol di(meth)acrylate may have at least one of an EO group and a PO group, or it 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 group and the PO group may be present in a continuous, block-like manner or randomly. The PO group may be either an oxy-n-propylene group or an oxyisopropylene group. In the case of a (poly)oxyisopropylene group, the secondary carbon of the propylene group may be bonded to the oxygen atom, or the primary carbon may be bonded to the oxygen atom.

[0066] Examples of commercially available polyalkylene glycol di(meth)acrylates include FA-023M, FA-024M (manufactured by Resonaq Corporation), and NK Ester 9PG (manufactured by Shin Nakamura Chemical Industry Co., Ltd.).

[0067] Component (B) may include a (meth)acrylate having a urethane bond, from the viewpoint of improving the flexibility of the resist pattern. Examples of (meth)acrylates having a urethane bond include addition products of a (meth)acrylic monomer having an OH group at the β position and a diisocyanate (isophorone diisocyanate, 2,6-toluene diisocyanate, 2,4-toluene diisocyanate, 1,6-hexamethylene diisocyanate, etc.), tris((meth)acryloxytetraethylene glycol isocyanate)hexamethylene isocyanurate, EO-modified urethane di(meth)acrylate, and EO,PO-modified urethane di(meth)acrylate.

[0068] Examples of commercially available EO-modified urethane di(meth)acrylate include UA-11 and UA-21EB (manufactured by Shin-Nakamura Chemical Industry Co., Ltd.). Examples of commercially available EO,PO-modified urethane di(meth)acrylate include UA-13 (manufactured by Shin-Nakamura Chemical Industry Co., Ltd.).

[0069] Component (B) may contain a (meth)acrylate compound having a skeleton derived from dipentaerythritol or pentaerythritol, from the viewpoint of facilitating the formation of thick resist patterns and improving resolution and adhesion in a balanced manner. The (meth)acrylate compound having a skeleton derived from dipentaerythritol or pentaerythritol may have four or more (meth)acryloyl groups and may be dipentaerythritol penta(meth)acrylate or dipentaerythritol hexa(meth)acrylate.

[0070] Component (B) may contain a bisphenol-type (meth)acrylate, or a bisphenol A-type (meth)acrylate, from the viewpoint of further improving resolution and peelability after curing. Examples of bisphenol A-type (meth)acrylates include 2,2-bis(4-((meth)acryloxypolyethoxy)phenyl)propane (EO-modified bisphenol A dimethacrylate), 2,2-bis(4-((meth)acryloxypolypropoxy)phenyl)propane (PO-modified bisphenol A dimethacrylate), 2,2-bis(4-((meth)acryloxypolybutoxy)phenyl)propane (BO-modified bisphenol A dimethacrylate), and 2,2-bis(4-((meth)acryloxypolyethoxypolypropoxy)phenyl)propane (EO,PO-modified bisphenol A dimethacrylate). Among these, component (B) may be 2,2-bis(4-((meth)acryloxypolyethoxy)phenyl)propane (EO-modified bisphenol A dimethacrylate) from the viewpoint of further improving resolution and pattern formation.

[0071] Commercially available bisphenol A type (meth)acrylate products include BPE-200, BPE-500 (manufactured by Shin-Nakamura Chemical Industry Co., Ltd.), FA-321M (manufactured by Resonaq Corporation), and BP-2EM (manufactured by Kyoeisha Chemical Co., Ltd.).

[0072] Examples of nonylphenoxypolyethylene oxyacrylates include nonylphenoxytetraethylene oxyacrylate, nonylphenoxypentaethylene oxyacrylate, nonylphenoxyhexaethylene oxyacrylate, nonylphenoxyheptaethylene oxyacrylate, nonylphenoxyoctaethylene oxyacrylate, nonylphenoxynonaethylene oxyacrylate, nonylphenoxydecaethylene oxyacrylate, and nonylphenoxyundaethylene oxyacrylate.

[0073] The content of component (B) may be 10 to 70 parts by mass, 15 to 60 parts by mass, or 20 to 50 parts by mass per 100 parts by mass of the total amount of components (A) and (B). When the content of component (B) is within this range, the strength of the photo-cured portion of the photosensitive layer tends to be better.

[0074] Component (A) and component (B) may be the main components of the photosensitive resin composition. The total content of component (A) and component (B) may be, for example, 70% by mass or more, 80% by mass or more, 90% by mass or more, or 95% by mass or more, and 99% by mass or less, based on the total amount of the photosensitive resin composition.

[0075] (C) Ingredient: Photopolymerization initiator Component (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.

[0076] (C) Examples of photopolymerization initiators include acylphosphine oxides, oxime esters, aromatic ketones, quinones, alkylphenones, imidazoles, acridines, phenylglycines, and coumarins.

[0077] As component (C), a hexaarylbiimidazole compound, an acridine compound, or an imidazole compound may be used to improve sensitivity and resolution in a balanced manner.

[0078] Examples of hexaarylbiimidazole compounds 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 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.

[0079] Among these, the hexaarylbiimidazole compound may be a 2-(o-chlorophenyl)-4,5-diphenylimidazole dimer from the viewpoint of sensitivity and adhesion. As a 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".

[0080] Examples of acridine compounds 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, and 1,8-bis(9-acridinyl) Examples include lysinyl 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.

[0081] Examples of imidazole compounds 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, and 2,2'-bi Examples include su-(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.

[0082] The content of component (C) may be 0.1 to 15 parts by mass, 0.5 to 10 parts by mass, or 1 to 8 parts by mass per 100 parts by mass of the total amount of components (A) and (B). When the content of component (C) is 0.1 parts by mass or more, the photosensitivity, resolution, and adhesion tend to improve, and when it is 10 parts by mass or less, the resist pattern formation properties tend to be superior.

[0083] (D) Ingredients: Sensitizer The photosensitive resin composition according to this embodiment may further contain a sensitizer (hereinafter sometimes referred to as "component (D)"). By containing component (D) in the photosensitive resin composition, when exposed with light having a peak within a specific wavelength range, a maximum absorption can be provided near that specific wavelength range, thereby increasing the sensitivity of the photosensitive resin composition. Component (D) can be used alone or in combination of two or more types.

[0084] 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 also contain dialkylaminobenzophenone compounds to further improve resolution.

[0085] Examples of dialkylaminobenzophenone compounds include 4,4'-bis(dimethylamino)benzophenone and 4,4'-bis(diethylamino)benzophenone.

[0086] 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 per 100 parts by mass of the total amount of components (A) and (B).

[0087] (E) Ingredients: Photochromic agent The photosensitive resin composition may further contain a photochromic agent (hereinafter sometimes referred to as "component (E)") to enhance the sensitivity of the photosensitive resin composition. The photochromic agent may be an amine compound. Examples of photochromic agents include tribromophenylsulfone, leucocrystal violet, diphenylamine, benzylamine, triphenylamine, diethylaniline, and o-chloroaniline.

[0088] Other ingredients The photosensitive resin composition according to this embodiment may further contain additives as needed, such as polymerization inhibitors, dyes, adhesion promoters, thermal color inhibitors, plasticizers, pigments, fillers, defoamers, flame retardants, leveling agents, release accelerators, antioxidants, fragrances, imaging agents, and thermal crosslinking agents. These additives can be used individually or in combination of two or more.

[0089] Examples of polymerization inhibitors include catechol compounds (such as 4-tert-butylcatechol) and hindered amines (such as 2,2,6,6-tetramethyl-4-hydroxypiperidine-1-oxyl).

[0090] Examples of dyes include malachite green, Victoria pure blue, brilliant green, and methyl violet.

[0091] Examples of adhesion-enhancing agents include triazoles (benzotriazole, tolyltriazole, carboxybenzotriazole, 1-hydroxybenzotriazole, etc.), imidazoles (1H-imidazole, 2-methylimidazole, 2-undecylimidazole, 2-ethyl-4-methylimidazole, etc.), and tetrazoles (1H-tetrazole, 5-amino-1H-tetrazole, 5,5'-azobis-1H-tetrazole, 1-methyl-5-mercapto-1H-tetrazole, 1-phenyl-5-mercapto-1H-tetrazole, etc.).

[0092] The photosensitive resin composition can be dissolved in solvents such as methanol, ethanol, acetone, methyl ethyl ketone, methyl cellosolve, ethyl cellosolve, toluene, N,N-dimethylformamide, propylene glycol monomethyl ether, or a mixture thereof, as needed, to prepare a solution with a solid content of approximately 30-60% by mass.

[0093] [Photosensitive element] Figure 1 is a schematic cross-sectional view showing one embodiment of a photosensitive element. The photosensitive element 1 according to this embodiment comprises a support 2 and a photosensitive layer 3 formed on the support 2, the photosensitive layer 3 containing the above-mentioned photosensitive resin composition. The photosensitive element 1 may also include other layers, such as a protective layer 4, which may be provided as needed. When using the photosensitive element according to this embodiment, the photosensitive layer may be laminated onto a substrate and then exposed without peeling off the support (support film).

[0094] Examples of support materials include polyester films such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polyethylene-2,6-naphthalate (PEN), as well as polyolefin films such as polypropylene and polyethylene. Among these, PET film may be used as the support material because it is readily available and has excellent handling properties in the manufacturing process (especially in terms of heat resistance, thermal shrinkage rate, and breaking strength).

[0095] The haze of the support may be 0.01 to 1.0% or 0.01 to 0.5%. A haze of 0.01% or more tends to make the support itself easier to manufacture, while a haze of 1.0% or less tends to reduce the minute defects that may occur in the resist pattern. "Haze" means the degree of cloudiness. In this specification, haze refers to the value measured using a commercially available cloudiness meter (turbidimeter) in accordance with the method specified in JIS K7136:2000. Haze can be measured with a commercially available turbidimeter such as the NDH-5000 (manufactured by Nippon Denshoku Industries Co., Ltd.).

[0096] The thickness of the support may be 1-100 μm, 5-60 μm, 10-50 μm, 10-40 μm, 10-30 μm, or 10-25 μm. A support thickness of 1 μm or more tends to suppress tearing of the support when it is peeled off. Furthermore, a support thickness of 100 μm or less can suppress the decrease in resolution when exposure is performed through the support.

[0097] The photosensitive element may further include a protective layer as needed. The protective layer may be a film such that the adhesive force between the photosensitive layer and the support is less than the adhesive force between the photosensitive layer and the support, or a low-fisheye film may be used. Specifically, examples include those that can be used as the support mentioned above. From the viewpoint of release from the photosensitive layer, it may be a polyethylene film.

[0098] The thickness of the protective layer varies depending on the application, but may be 1-100 μm, 5-50 μm, 5-30 μm, or 15-30 μm. A protective layer thickness of 1 μm or more tends to suppress tearing of the protective layer when it is peeled off, while a protective layer thickness of 100 μm or less tends to be cost-effective.

[0099] A photosensitive element can be manufactured, for example, as follows: a solution of a photosensitive resin composition (coating solution) is applied to a support to form a coating layer, and this is dried to form a photosensitive layer. Then, the side of the photosensitive layer opposite to the support is covered with a protective layer to obtain a photosensitive element comprising a support, a photosensitive layer formed on the support, and a protective layer laminated on the photosensitive layer.

[0100] The coating solution can be applied to the support by known methods such as roll coating, comma coating, gravure coating, air knife coating, die coating, and bar coating.

[0101] The drying of the coating layer is not particularly limited as long as at least a portion of the organic solvent can be removed from the coating layer. Drying conditions may be, for example, 70 to 150°C for 5 to 30 minutes. After drying, the amount of residual solvent in the photosensitive layer may be 2% by mass or less, from the viewpoint of preventing solvent diffusion in subsequent processes.

[0102] The thickness of the photosensitive layer in a photosensitive element can be appropriately selected depending on the application, but the thickness after drying may be 1-100 μm, 5-50 μm, or 10-40 μm. A thickness of 1 μm or more facilitates industrial coating and improves productivity. Conversely, a thickness of 100 μm or less improves adhesion and resolution.

[0103] The transmittance of the photosensitive layer to ultraviolet light at a wavelength of 365 nm may be 5-75%, 7-60%, or 10-40%. A transmittance of 5% or higher tends to improve adhesion, while a transmittance of 75% or lower tends to improve resolution. The transmittance can be measured using a UV spectrometer.

[0104] The form of the photosensitive element is not particularly limited. The form of the photosensitive element may be, for example, a sheet, or it may be wound in a roll on a core. When wound in a roll, the support film may be wound on the outside. Examples of the core include plastics such as polyethylene resin, polypropylene resin, polystyrene resin, polyvinyl chloride resin, or ABS resin (acrylonitrile-butadiene-styrene copolymer).

[0105] An end separator may be installed on the end face of the roll-shaped photosensitive element for end face protection, or a moisture-proof end separator may be installed to prevent edge fusion (resin seepage). The photosensitive element may be wrapped and packaged in a black sheet with low moisture permeability.

[0106] Photosensitive elements can be suitably used, for example, in the resist pattern formation method described later. In particular, from the viewpoint of resolution, photosensitive elements are suitable for application in manufacturing methods that form conductive patterns by plating.

[0107] [Method for forming a resist pattern] The resist pattern formation method of this embodiment comprises: (i) forming a photosensitive layer on a substrate using the photosensitive resin composition or the photosensitive element (photosensitive layer formation step); (ii) irradiating at least a part (a predetermined part) of the photosensitive layer with active light to form a photocured portion (exposure step); and (iii) removing at least a part other than the photocured portion from the substrate to form a resist pattern (development step). The resist pattern formation method of this embodiment may include other steps as needed. The resist pattern can also be called a photocured pattern of the photosensitive resin composition or a relief pattern. The resist pattern formation method can also be called a method for manufacturing a substrate with a resist pattern.

[0108] (i) Photosensitive layer formation process As a method for forming a photosensitive layer on a substrate, for example, the above-mentioned photosensitive resin composition may be applied and dried, or, after removing the protective layer from the photosensitive element, the photosensitive layer of the photosensitive element may be pressed onto the substrate while heating. When a photosensitive element is used, a laminate is obtained in which the substrate, the photosensitive layer, and the support are stacked in order. The above-mentioned substrate is not particularly limited, but typically includes a circuit forming substrate having an insulating layer and a conductive layer formed on the insulating layer, or a die pad (lead frame substrate) such as an alloy substrate.

[0109] When using a photosensitive element, the photosensitive layer formation process is preferably carried out under reduced pressure from the viewpoint of adhesion and conformability. Heating of the photosensitive layer and / or substrate during bonding may be carried out at a temperature of 70 to 130°C. Bonding should be performed at approximately 0.1 to 1.0 MPa (1 to 10 kgf / cm²). 2The process may be carried out under pressure of a certain degree, but these conditions should be selected as appropriate as needed. Note that if the photosensitive layer is heated to 70-130°C, preheating the substrate is not necessary; however, preheating the substrate can be performed to further improve adhesion and conformability.

[0110] (ii) Exposure process In the exposure process, at least a portion of the photosensitive layer formed on the substrate is irradiated with active light, causing the irradiated portion to photocur and form a latent image. If a support is present on the photosensitive layer, and the support is transparent to the active light, the active light can be irradiated through the support. However, if the support is light-blocking, the support is removed before irradiating the photosensitive layer with active light.

[0111] One exposure method is to irradiate the image with active light through a negative or positive mask pattern called artwork (mask exposure method). Alternatively, other exposure methods may be employed, such as projection exposure, direct drawing exposure, or DLP (Digital Light Processing) exposure.

[0112] A known light source can be used for the active light source. Examples of active light sources include carbon arc lamps, mercury vapor arc lamps, high-pressure mercury lamps, xenon lamps, gas lasers (argon lasers, etc.), solid-state lasers (YAG lasers, etc.), semiconductor lasers, etc., which effectively emit ultraviolet or visible light.

[0113] (iii) Development process In the development process, 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.

[0114] If a support is present on the photosensitive layer, the support is removed before removing (developing) the areas other than the photocured area (unexposed areas). There are two development methods: wet development and dry development, with wet development being more widely used.

[0115] In the case of wet development, development is carried out using a developer solution corresponding to the photosensitive resin composition and a known development method. Examples of development methods include the dip method, paddle method, spray method, brushing, slashing, scrubbing, and agitation immersion. From the viewpoint of improving resolution, a high-pressure spray method may also be used. Two or more of these development methods may be combined.

[0116] The composition of the developer is appropriately selected according to the composition of the photosensitive resin composition described above. Examples of developers include alkaline aqueous solutions and organic solvent developers.

[0117] From the viewpoint of safety, stability, and ease of use, the developer may be an alkaline aqueous solution. Examples of bases in alkaline aqueous solutions include alkali hydroxides such as lithium, sodium, or potassium hydroxides; alkali carbonates such as lithium, sodium, potassium, or ammonium carbonates and bicarbonates; 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.

[0118] Examples of alkaline aqueous solutions include dilute solutions of 0.1-5% by mass sodium carbonate, 0.1-5% by mass potassium carbonate, 0.1-5% by mass sodium hydroxide, and 0.1-5% by mass sodium tetraborate. The pH of the alkaline aqueous solution may be in the range of 9-14, and its 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, and a small amount of organic solvent to accelerate development.

[0119] Examples of organic solvents used in alkaline aqueous solutions include acetone, ethyl acetate, alkoxyethanol having alkoxy groups with 1 to 4 carbon atoms, ethyl alcohol, isopropyl alcohol, butyl alcohol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, and diethylene glycol monobutyl ether.

[0120] Examples of organic solvents used in organic solvent developers include 1,1,1-trichloroethane, N-methyl-2-pyrrolidone, N,N-dimethylformamide, cyclohexanone, methyl isobutyl ketone, and γ-butyrolactone. Water may be added to these organic solvents to prevent ignition, thus forming an organic solvent developer. The amount of water may be in the range of 1 to 20% by mass.

[0121] In the resist pattern formation method of this embodiment, after removing the uncured portion in the development step, heating at 60 to 250°C or 0.2 to 10 J / cm² is performed as necessary. 2 The system may also include a step to further harden the resist pattern by performing exposure.

[0122] [Method for forming wiring patterns] The wiring pattern formation method according to this embodiment includes a step of forming a conductor pattern by etching or plating a substrate on which a resist pattern has been formed by the resist pattern formation method described above. The wiring pattern formation method may further include a step of removing the photocured portion with an alkaline aqueous solution after the etching or plating process.

[0123] In the plating process, a resist pattern formed on the substrate is used as a mask, and the conductive layer provided on the substrate is plated. After the plating process, the resist is removed by removing the resist pattern as described later, and the conductive layer that was covered by this resist may be further etched to form a conductive pattern. Examples of plating processes include electrolytic plating and electroless plating. The plating process may be electroless plating.

[0124] In the etching process, a resist pattern formed on the 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.

[0125] After etching or plating, the resist pattern on the substrate may be removed. The resist pattern can be removed, for example, by using an aqueous solution that is even more strongly alkaline than the alkaline aqueous solution used in the development step. Examples of strongly alkaline aqueous solutions include 1-10% by mass sodium hydroxide aqueous solution and 1-10% by mass potassium hydroxide aqueous solution. The resist pattern may also be removed using a strongly alkaline aqueous solution at 45-65°C.

[0126] After plating and removing the resist pattern, the conductive layer covered with the resist can be further etched to form a conductive pattern, thereby manufacturing the desired printed circuit board. The etching method used in this process is appropriately selected depending on the conductive layer to be removed. For example, the etching solution described above can be applied.

[0127] The wiring pattern formation method according to this embodiment is applicable not only to the manufacture of single-layer printed circuit boards but also to the manufacture of multi-layer printed circuit boards, and furthermore, to the manufacture of printed circuit boards having small-diameter through-holes. [Examples]

[0128] The present disclosure will be described in detail below based on examples, but the present disclosure is not limited thereto.

[0129] [Synthesis of polymers] (Examples 1-1 to 1-3 and Comparative Examples 1-1 to 1-6) Solution X1 was prepared by adding styrene (monomer 1), benzyl methacrylate (monomer 2), methacrylic acid (monomer 3), hydroxyethyl methacrylate (monomer 4), N-(1,1,3,3-tetramethylbutyl)acrylamide (acrylamide 1), diacetone acrylamide (acrylamide 2), N-tert-butylacrylamide (acrylamide 3), Nn-butylacrylamide (acrylamide 4), 2-ethylhexyl-β-mercaptopropionic acid (chain transfer agent), toluene (solvent 1), and 1-methoxy-2-propanol (solvent 2) to a flask equipped with a stirrer, reflux condenser, thermometer, dropping funnel, and nitrogen inlet tube. Separately, Solution X2 was prepared by adding toluene (solvent 1) and 1-methoxy-2-propanol (solvent 2) to 2,2'-azobis(isobutyronitrile) (polymerization initiator). Table 1 shows the amounts (in g) of each component. Note that the amount (in g) of Solvent 1 shown in Table 1 is the total amount of Solvent 1 in Solution X1 and Solvent 1 in Solution X2, and the amount (in g) of Solvent 2 shown in Table 2 is the total amount of Solvent 2 in Solution X1 and Solvent 2 in Solution X2. Solution X1 was heated to 70°C while stirring under a nitrogen atmosphere, and Solution X2 was added dropwise to the flask over 30 minutes. Then, the mixture was stirred at 75°C for 90 minutes, at 85°C for 2 hours, and at 95°C for 2 hours, and the reaction mixture was cooled to room temperature. After removing toluene from the reaction mixture under reduced pressure, the residue was added to water, and the precipitate was collected and dried to obtain polymers A1-1 to A1-3 and polymers a1-1 to a1-6.

[0130] The polymer's Mw was measured by gel permeation chromatography (GPC) and derived by conversion using a calibration curve for standard polystyrene. The calibration curve was approximated by a cubic universal calibration curve according to JIS K 7252-2 (2016), using a set of five standard polystyrene samples (PStQuick MP-H, PStQuick B (manufactured by Tosoh Corporation, product name)). The GPC conditions are shown below.

[0131] (GPC conditions) Pump, detector: HLC-8320 (manufactured by Tosoh Corporation) Column: TSKgel SuperMultipore HZ-M (3 tubes) (Manufactured by Tosoh Corporation) Eluent: Tetrahydrofuran (THF) Measurement temperature: 40℃ Flow rate: 0.35mL / min

[0132] [Table 1]

[0133] [Preparation of photosensitive resin composition] (Examples 2-1 to 2-3 and Comparative Examples 2-1 to 2-6) (A) The photosensitive resin compositions of Examples 2-1 to 2-3 and Comparative Examples 2-1 to 2-6 were prepared by mixing each component in the amounts (unit: parts by mass) shown in Table 2 with 60 parts by mass of each polymer (solid content) as component (A).

[0134] The details of each component shown in Table 2 are as follows: (B) Component: Photopolymerizable compound B-1: EO-modified bisphenol A dimethacrylate (manufactured by Resonaq Corporation, product name: FA-321M) B-2: EO-modified bisphenol A dimethacrylate (manufactured by Kyoeisha Chemical Co., Ltd., product name: BP-2EM) B-3: EO-modified polypropylene glycol dimethacrylate (manufactured by Resonaq Corporation, product name: FA-024M) (C) Ingredient: Photopolymerization initiator C-1: 2,2'-Bis(2-chlorophenyl)-4,4',5,5'-tetraphenylbiimidazole (manufactured by Hodogaya Chemical Co., Ltd., trade name: B-CIM) (D) Ingredients: Sensitizer D-1: 4,4'-Bis(diethylamino)benzophenone (manufactured by Hodogaya Chemical Co., Ltd.) (E) Ingredients: Photochromic agent E-1: Leucocrystal violet (manufactured by Yamada Chemical Co., Ltd.) Other ingredients • Polymerization inhibitors F-1: 4-tert-butylcatechol (manufactured by Fujifilm Wako Pure Chemical Corporation) ·dye G-1: Malachite Green (manufactured by Osaka Organic Chemical Industry Co., Ltd.) • Adhesion enhancer H-1: Benzotriazole derivative (manufactured by Sanwa Chemical Co., Ltd., product name: SF-808H) solvent I-1: Toluene I-2: Methanol I-3: Acetone

[0135] [Table 2]

[0136] [Photosensitive element] A photosensitive resin composition was applied to a 25 μm thick PET film (Teijin Film Solutions Limited (now Toyobo Co., Ltd.), product name: G2) (support) and dried in a 100°C hot air convection dryer for 4 minutes to form a photosensitive layer with a thickness of 25 μm after drying. A polypropylene film (Tamapoly Co., Ltd., product name: NF-13) (protective layer) was laminated onto this photosensitive layer to obtain a photosensitive element in which the support, photosensitive layer, and protective layer were laminated in this order.

[0137] [evaluation] The following evaluations were performed using a photosensitive element. The results are shown in Table 3.

[0138] <Stickiness> After heating the photosensitive element to 30°C, the protective film was removed, and the presence or absence of stickiness on the surface of the photosensitive layer was checked.

[0139] <Followability 1> Ten layers of photosensitive material were stacked on top of each other to create an evaluation sample (thickness: approximately 250 μm), which was then laminated at 80°C and 0.4 MPa for 20 seconds. An 8 mm diameter sample stage was set up in a viscoelasticity measuring device (product name: ARES G2, manufactured by TA Instruments). After setting the evaluation sample on the sample stage, the complex viscosity was measured while the temperature was increased from 30°C to 160°C at a heating rate of 5°C / min. The conformability was evaluated based on the complex viscosity at 105°C. A complex viscosity of less than 500 Pa·s at 105°C was evaluated as "A" for excellent conformability, and a complex viscosity of 500 Pa·s or more was evaluated as "B". A low complex viscosity at 105°C indicates that the resin can conform to recesses in the circuit board, etc., and that it has excellent conformability.

[0140] <Followability 2> (Fabrication of laminates) A copper-clad laminate (manufactured by Resonaq Corporation, product name MCL-E-67) was prepared by laminating copper foil (35 mm thick) onto 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 of the copper surfaces of the copper-clad laminate, and then it was immersed in an etching solution. Next, the photoresist was 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.

[0141] A photosensitive element was laminated onto the copper surface of a copper-clad laminate, on a grooved surface of the laminate. Lamination was performed using a 110°C heat roll, removing the protective layer, at a pressure of 0.4 MPa and a roll speed of 1.0 m / min. In this way, a laminate was obtained in which the copper-clad laminate, the photosensitive layer, and the support were laminated in this order.

[0142] (Observation of voids) Using an ultraviolet exposure machine (Mikasa Corporation, product name: MA-20) equipped with a photomask having a rectangular pattern with a line width / space width of 100 μm / 100 μm formed on it, the photomask pattern and groove direction are perpendicular to the support surface of the laminate, and the exposure is 10 mJ / cm². 2Ultraviolet light was irradiated onto the surface. Illuminance was measured using an ultraviolet illuminometer (Ushio Inc., product name: UIT-150) fitted with a 365nm probe. After exposure, the support was peeled off, and the unexposed areas were removed by spraying a 1% by mass sodium carbonate aqueous solution onto the photosensitive layer at 30°C for 90 seconds (development process). After development, the presence or absence of voids between the photosensitive layer and the grooves of the copper-clad laminate was observed using a scanning electron microscope (Hitachi High-Tech Corporation, product name: Hitachi High-Tech Corporation). If no voids were observed, the surface was evaluated as having excellent conformability as "A," and if voids were observed, it was evaluated as "B."

[0143] <Resolution> (Preparation of the laminate) A copper-clad laminate (Resonac, MCL-E679) was prepared by laminating a copper foil (18 μm thick) treated with CZ roughening onto both sides of a glass fiber reinforced epoxy resin layer. The photosensitive layer of the photosensitive element was laminated onto the CZ-roughened copper-clad laminate at 60°C and a pressure of 0.4 MPa to obtain a laminate in which the copper-clad laminate, the photosensitive layer, and the support were laminated in this order.

[0144] (Evaluation of resolution) Using an ultraviolet exposure machine (Mikasa Corporation, product name: MA-20) equipped with a photomask having five rectangular patterns formed on it with a line width / space width ratio of 1:1, the photomask pattern and groove direction are perpendicular to the support surface of the laminate, and the exposure is 10 mJ / cm². 2 The sample was irradiated with ultraviolet light. Illuminance was measured using an ultraviolet illuminometer (Ushio Inc., product name: UIT-150) fitted with a 365nm probe. After exposure, the support was peeled off, and the unexposed areas were removed by spraying a 1% by mass sodium carbonate aqueous solution onto the photosensitive layer at 30°C for 90 seconds (development process). The pattern of the photoresist after development was checked, and the smallest line width that could be resolved properly was recorded. The smaller the smallest line width (for example, line width / space width of 8μm:8μm or less), the better the resolution. (Rectangular pattern with a line width / space width ratio of 1:1 (unit: μm)) 100:100, 80:80, 60:60, 40:40, 30:30, 20:20, 15:15, 10:10, 8:8, 7:7, 6:6, 5:5, 4:4, 3:3, 2:2, 1:1

[0145] <Adhesion> (Preparation of the laminate) The laminate was prepared in the same manner as described in the resolution evaluation test.

[0146] (Evaluation of adhesion) Using a UV exposure machine (Mikasa Corporation, product name: MA-20) equipped with a photomask having four rectangular lines formed on it with a line width / space width ratio of 1:4, the photomask pattern and groove direction are perpendicular to the support surface of the laminate, and the exposure is 10 mJ / cm². 2 The sample was irradiated with ultraviolet light. Illuminance was measured using an ultraviolet illuminometer (Ushio Inc., product name: UIT-150) fitted with a 365nm probe. After exposure, the support was peeled off, and the unexposed areas were removed by spraying a 1% by mass sodium carbonate aqueous solution onto the photosensitive layer at 30°C for 90 seconds (development process). The pattern of the photoresist after development was checked, and the smallest line width that could be resolved properly was recorded. The smaller the smallest line width (for example, line width / space width of 8μm:32μm or less), the better the adhesion. (Rectangular pattern with a line width / space width ratio of 1:4 (unit: μm)) 100:400, 80:320, 60:240, 40:160, 30:120, 20:80, 15:60, 10:40, 8:32, 7:28, 6:24, 5:20, 4:16, 3:12, 2:8, 1:4

[0147] <Storage stability> Evaluation samples were prepared by stacking 10 photosensitive elements cut into 20mm squares. The evaluation samples were placed in a constant temperature and humidity chamber, with a weight placed on top, and stored for 70 hours at 40°C and 50% humidity. The mass loss rate (%) of the evaluation samples was measured based on the following formula. The smaller the mass loss rate (%) of the evaluation sample (for example, less than 2.0%), the less resin seepage there is, and the better the storage stability. Mass loss rate (%) = [(Mass of evaluation sample before storage - Mass of evaluation sample after storage) / (Mass of evaluation sample before storage)] × 100

[0148] [Table 3]

[0149] As shown in Table 3, the photosensitive resin composition of the example containing the specified polymer exhibited excellent resolution, adhesion, and storage stability, whereas the photosensitive resin composition of the comparative example not containing the specified polymer lacked sufficient resolution, adhesion, and storage stability in at least one of these properties. The photosensitive resin composition of the example was found to be non-sticky and excellent in terms of conformability. These results confirm that the photosensitive resin composition of this disclosure exhibits excellent resolution, adhesion, and storage stability. [Explanation of symbols]

[0150] 1...Photosensitive element, 2...Support, 3...Photosensitive layer, 4...Protective layer.

Claims

1. A binder resin comprising a polymer containing structural units represented by the following formula (I) and structural units having a carboxyl group, Photopolymerizable compounds, Photopolymerization initiator, A photosensitive resin composition containing [a specific substance]. 【Chemistry 1】 [In formula (I), R １ R represents a hydrogen atom or a methyl group. ２ This represents an alkyl group having a chain-like structure in which four or more carbon atoms are continuously linked by single bonds from an adjacent nitrogen atom, and having a total of five or more carbon atoms.

2. The photosensitive resin composition according to claim 1, wherein the content of the structural unit represented by formula (I) is 5 to 50% by mass based on the total amount of the polymer.

3. The photosensitive resin composition according to claim 1 or 2, wherein the photopolymerization initiator comprises a hexaarylbiimidazole compound.

4. The photosensitive resin composition according to claim 1 or 2, further comprising a sensitizer.

5. The photosensitive resin composition according to claim 1 or 2, further comprising a photochromic agent.

6. It comprises a support film and a photosensitive layer formed on the support film, A photosensitive element wherein the photosensitive layer comprises the photosensitive resin composition described in claim 1 or 2.

7. A step of forming a photosensitive layer on a substrate using the photosensitive resin composition described in claim 1 or 2, The steps include irradiating at least a portion of the photosensitive layer with active light to form a photocured portion, A step of 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 the following features.

8. A step of forming a photosensitive layer on a substrate using the photosensitive element described in claim 6, The steps include irradiating at least a portion of the photosensitive layer with active light to form a photocured portion, A step of 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 the following features.

9. 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 resist pattern forming method described in claim 7 to form a conductor pattern.

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 resist pattern forming method described in claim 8 to form a conductor pattern.

11. The method for forming a wiring pattern according to claim 9, further comprising the step of removing the photocured portion with an alkaline aqueous solution after the etching or plating process.

12. 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 or plating process.

13. A polymer comprising a structural unit represented by the following formula (I) and a structural unit having a carboxyl group. 【Chemistry 2】 [In formula (I), R １ R represents a hydrogen atom or a methyl group. ２ This represents an alkyl group having a chain-like structure in which four or more carbon atoms are continuously linked by single bonds from an adjacent nitrogen atom, and having a total of five or more carbon atoms.

14. The polymer according to claim 13, wherein the content of the structural unit represented by formula (I) is 5 to 50% by mass based on the total amount of the polymer.

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