WO2022201432A1

WO2022201432A1 - Photosensitive resin film, resist pattern forming method, and method for forming wiring pattern

Info

Publication number: WO2022201432A1
Application number: PCT/JP2021/012569
Authority: WO
Inventors: 穣川上; 尚樹平松
Original assignee: 昭和電工マテリアルズ株式会社
Priority date: 2021-03-25
Filing date: 2021-03-25
Publication date: 2022-09-29
Also published as: JPWO2022201432A1; KR20230158050A; CN117099044A

Abstract

The present disclosure relates to: a photosensitive resin film that contains a binder polymer, a photopolymerizable compound including an acrylate compound, a photopolymerization initiator, and a polymerization inhibitor, and that has a thickness of 35-300 μm; a method for forming a resist pattern using the photosensitive resin film; and a method for forming a wiring pattern.

Description

Photosensitive resin film, method for forming resist pattern, and method for forming wiring pattern

The present disclosure relates to a photosensitive resin film, a method of forming a resist pattern, and a method of forming a wiring pattern.

In the field of manufacturing semiconductor integrated circuits (LSI) or wiring boards, photosensitive materials are used as resists for making conductor patterns. For example, in the manufacture of wiring boards, a photosensitive resin composition is used to form a resist, and then a conductive pattern, metal posts, and the like are formed by plating. More specifically, a photosensitive layer is formed on a substrate using a photosensitive resin composition or the like, the photosensitive layer is exposed through a predetermined mask pattern, and then a conductor pattern, metal posts, etc. are formed. A resist pattern (resist) is formed by developing so that portions can be selectively removed (peeled off). Next, a conductor such as copper is formed on the removed portion by plating, and then the resist pattern is removed to manufacture a wiring board having a conductor pattern, metal posts, etc. (for example,

Patent Documents

1 and 2 reference).

JP-A-2000-356852 WO2008/064803

For electronic parts such as inductors, it is being studied to increase the thickness of the conductor layer to form a wiring pattern with a high aspect ratio, and to shorten and shorten each process in order to improve production efficiency. . Therefore, the photosensitive resin film is required to be capable of forming a thick resist pattern and to shorten the peeling time of the formed resist pattern.

The present disclosure has been made in view of the above circumstances, and includes a photosensitive resin film capable of achieving both pattern formability and peeling properties, a method for forming a resist pattern using the same, and a method for forming a wiring pattern. intended to provide

A photosensitive resin film according to the present disclosure contains a binder polymer, a photopolymerizable compound containing an acrylate compound, a photopolymerization initiator, and a polymerization inhibitor, and has a thickness of 35 to 300 μm.

A method for forming a resist pattern according to the present disclosure includes the steps of providing a photosensitive layer on a substrate using the photosensitive resin film described above, and irradiating at least a portion of the photosensitive layer with actinic rays to form a photocured portion. and removing at least part of the photosensitive layer other than the photocured portion to form a resist pattern.

The method of forming a wiring pattern according to the present disclosure includes the steps of plating a substrate on which a resist pattern is formed by the method of forming a resist pattern to form a conductor pattern, and removing the photocured portion after the plating. and

According to the present disclosure, it is possible to provide a photosensitive resin film that can achieve both pattern formability and peeling properties, a resist pattern forming method using the same, and a wiring pattern forming method.

It is a schematic cross section showing one embodiment of a photosensitive resin film. It is a figure which shows typically one aspect|mode of the process of forming a wiring pattern.

The present disclosure will be described in detail below. In this specification, a numerical range indicated using "to" indicates a range including the numerical values before and after "to" as the minimum and maximum values, respectively. In addition, in the numerical ranges described stepwise in this specification, the upper limit or lower limit of the numerical range at one stage may be replaced with the upper limit or lower limit of the numerical range at another stage. In the numerical ranges described herein, the upper or lower limits of the numerical ranges may be replaced with the values shown in the examples.

In this specification, "(meth)acrylic acid" means at least one of "acrylic acid" and "methacrylic acid" corresponding thereto, and the same applies to other similar expressions such as (meth)acrylate. Further, the "acrylate compound" includes a compound having an acryloyl group, and the "methacrylate compound" includes a compound having a methacryloyl group.

As used herein, the term “solid content” refers to non-volatile content excluding volatile substances such as water and solvents contained in the photosensitive resin composition, and when the resin composition is dried, It also includes those that are liquid, syrup-like, and wax-like at room temperature around 25°C.

[Photosensitive resin film]
The photosensitive resin film according to this embodiment contains a binder polymer, a photopolymerizable compound containing an acrylate compound, a photopolymerization initiator, and a polymerization inhibitor, and has a thickness of 35 to 300 μm.

The photosensitive resin film according to this embodiment can be produced using a photosensitive resin composition containing a binder polymer, a photopolymerizable compound, a photopolymerization initiator, and a polymerization inhibitor. Each component used in the photosensitive resin film and the photosensitive resin composition will be described in detail below.

((A) binder polymer)
(A) The binder polymer (hereinafter also referred to as "(A) component") can be produced, for example, by radically polymerizing a polymerizable monomer. Examples of polymerizable monomers include styrene or styrene derivatives, polymerizable monomers having a carboxy group, polymerizable monomers having a hydroxyl group, (meth)acrylic acid benzyl esters, (meth)acrylic acid alkyl esters, Acrylamides such as (meth)acrylic acid tetrahydrofurfuryl ester, (meth)acrylic acid dimethylaminoethyl ester, (meth)acrylic acid diethylaminoethyl ester, (meth)acrylic acid glycidyl ester, diacetone acrylamide, acrylonitrile, alkyl vinyl ether, 2 , 2,2-trifluoroethyl (meth)acrylate, and 2,2,3,3-tetrafluoropropyl (meth)acrylate. A polymerizable monomer can be used individually by 1 type or in combination of 2 or more types.

The (A) component may have a structural unit based on styrene or a styrene derivative from the viewpoint of adhesion and peeling properties. Styrene derivatives are polymerizable compounds such as vinyltoluene, α-methylstyrene, etc., in which the hydrogen atom at the α-position or aromatic ring of styrene is substituted. The component (A) can be produced, for example, by radically polymerizing a polymerizable monomer containing styrene or a styrene derivative and another polymerizable monomer.

The content of structural units based on styrene or styrene derivatives in component (A) may be 15 to 64% by mass, 25 to 60% by mass, 35 to 55% by mass, or 45 to 50% by mass. When the content of the structural unit based on styrene or a styrene derivative is 15% by mass or more, the adhesion tends to be improved, and when it is 64% by mass or less, it is possible to suppress the size of the peeled pieces during development and shorten the time required for peeling. There is a tendency to suppress prolongation.

The (A) component may have a carboxy group from the viewpoint of alkali developability. Examples of the polymerizable monomer 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 monoesters such as 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. From the viewpoint of further improving alkali developability, the polymerizable monomer having a carboxy group may be (meth)acrylic acid or methacrylic acid.

From the viewpoint of improving the alkali developability and alkali resistance in a well-balanced manner, the content of the structural unit based on the polymerizable monomer having a carboxy group is 10 to 50% by mass, based on the total amount of the component (A). It may be 15 to 40% by mass, or 20 to 35% by mass. When the content of the structural unit based on the polymerizable monomer having a carboxy group is 10% by mass or more, the alkali developability tends to be improved, and when it is 50% by mass or less, the alkali resistance tends to be excellent.

The (A) component may have a hydroxyl group from the viewpoint of subdividing the exfoliated pieces. Polymerizable monomers having a hydroxyl group include, for example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3 - hydroxyl group-containing (meth)acrylates such as hydroxybutyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate; and hydroxyl group-containing vinyl ethers such as 2-hydroxyethyl vinyl ether, 3-hydroxypropyl vinyl ether and 4-hydroxybutyl vinyl ether. be done.

From the viewpoint of improving the pattern formability and peeling properties in a well-balanced manner, the content of the structural unit based on the polymerizable monomer having a hydroxyl group is 0.5 to 15% by mass based on the total amount of component (A). , 1 to 10% by weight, or 2 to 5% by weight.

From the viewpoint of resolution and aspect ratio, the component (A) may have a structural unit based on benzyl (meth)acrylate. The content of structural units derived from (meth)acrylic acid benzyl ester in component (A) is 5 to 40% by mass, 10 to 35% by mass, or 15 to 30% by mass from the viewpoint of improving resolution and aspect ratio. %.

The (A) component may have a structural unit based on a (meth)acrylic acid alkyl ester from the viewpoint of improving the plasticity of the resist pattern. Examples of (meth)acrylic acid alkyl esters include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, pentyl (meth)acrylate, and (meth)acrylate. hexyl acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, undecyl (meth)acrylate, and ( Meth) dodecyl acrylate.

The acid value of component (A) is 100 to 220 mgKOH/g, 120 to 210 mgKOH/g, 140 to 200 mgKOH/g, 160 to 195 mgKOH/g, or It may be 170-190 mg KOH/g.

The weight average molecular weight (Mw) of component (A) may be 10,000 to 100,000, 15,000 to 80,000, 18,000 to 60,000, 20,000 to 50,000, or 25,000 to 40,000. When the Mw of the component (A) is 10,000 or more, the developer resistance of the photocured portion tends to be excellent. Component (A) may have a dispersity (weight average molecular weight/number average molecular weight) of 1.0 to 3.0, or 1.0 to 2.0. Resolution tends to improve as the degree of dispersion decreases.

The weight average molecular weight and number average molecular weight in this specification are values measured by gel permeation chromatography (GPC) and converted from standard polystyrene as a standard sample.

The (A) component can be used singly or in combination of two or more. As the component (A) when two or more are used in combination, for example, two or more binder polymers composed of different polymerizable monomers, two or more binder polymers having different Mw, and different dispersities. Two or more binder polymers are included.

The content of component (A) is 30 to 80 parts by mass, 40 to 75 parts by mass, 50 to 70 parts by mass, or 50 to It may be 60 parts by mass. When the content of the component (A) is within this range, the strength of the photocured portion of the photosensitive resin film and the photosensitive layer will be better.

((B) photopolymerizable compound)
By including an acrylate compound as (B) a photopolymerizable compound (hereinafter also referred to as "component (B)"), the photosensitive resin film forms a thick resist pattern with excellent adhesion during development. In addition, the time required for stripping the formed resist pattern can be shortened. The present inventors presume that the acryloyl group has no methyl group, is less hydrophobic than the methacryloyl group, and has no steric hindrance due to the methyl group, making it easier to remove the resist pattern with a stripping solution.

The acrylate compound is not particularly limited as long as it has at least one acryloyl group, and may have two or more acryloyl groups. Examples of acrylate compounds include acrylates having a polyhydric alcohol-derived skeleton, acrylates having a urethane bond, acrylates having a bisphenol skeleton, acrylates having an alicyclic skeleton, acrylates having a phthalic acid skeleton, nonylphenoxypolyethyleneoxyacrylate, and acrylic acid alkyl esters. An acrylate compound can be used individually by 1 type or in combination of 2 or more types.

Examples of acrylates having a polyhydric alcohol-derived skeleton include polyalkylene glycol diacrylate, trimethylolpropane diacrylate, trimethylolpropane triacrylate, EO-modified trimethylolpropane triacrylate, PO-modified trimethylolpropane triacrylate, EO, Examples include PO-modified trimethylolpropane triacrylate, tetramethylolmethane triacrylate, tetramethylolmethane tetraacrylate, and acrylates having a skeleton derived from dipentaerythritol or pentaerythritol. "EO-modified" means having a block structure of ethylene oxide (EO) groups, and "PO-modified" means having a block structure of propylene oxide (PO) groups.

A polyalkylene glycol diacrylate 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 the polyalkylene glycol diacrylate having both EO groups and PO groups, the EO groups and PO groups may be present continuously in blocks or randomly. Also, the PO group may be either an oxy-n-propylene group or an oxyisopropylene group. In addition, in the (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.

The acrylate having a urethane bond includes, for example, an 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.). Addition reactants, tris(acryloxytetraethyleneglycol isocyanate) hexamethylene isocyanurate, EO-modified urethane diacrylate, and EO,PO-modified urethane diacrylate.

Examples of acrylates having a bisphenol skeleton include 2,2-bis(4-(acryloxypolyethoxy)phenyl)propane, 2,2-bis(4-(acryloxypolypropoxy)phenyl)propane, 2,2- Bis(4-(acryloxypolybutoxy)phenyl)propane and 2,2-bis(4-(acryloxypolyethoxypolypropoxy)phenyl)propane. Among them, 2,2-bis(4-(acryloxypolyethoxy)phenyl)propane is preferable from the viewpoint of further improving pattern formability.

As the acrylate having an alicyclic skeleton, an acrylate having an alicyclic hydrocarbon group having 5 to 20 carbon atoms can be used. Alicyclic skeletons include, for example, cyclopentane, cyclohexane, cyclooctane, cyclodecane, norbornane, dicyclopentane, and tricyclodecane. Among these, the acrylate compound may be an acrylate having a tricyclodecane skeleton in order to further improve the peeling properties. Examples of acrylates having an alicyclic skeleton include dicyclopentenyl acrylate, dicyclopentanyl acrylate, dicyclopentenyloxyethyl acrylate, cyclohexyl acrylate, cyclohexyl diacrylate, and tricyclodecane dimethanol diacrylate. Examples of commercial products of tricyclodecanedimethanol diacrylate include A-DCP (tricyclodecanedimethanol diacrylate, manufactured by Shin-Nakamura Chemical Co., Ltd.).

Examples of acrylates having a phthalic acid skeleton include γ-chloro-β-hydroxypropyl-β'-acryloyloxyethyl-o-phthalate, β-hydroxyethyl-β'-acryloyloxyethyl-o-phthalate, and β- Hydroxypropyl-β'-acryloyloxyethyl-o-phthalate can be mentioned.

Examples of nonylphenoxypolyethyleneoxyacrylate include nonylphenoxytetraethyleneoxyacrylate, nonylphenoxypentaethyleneoxyacrylate, nonylphenoxyhexaethyleneoxyacrylate, nonylphenoxyheptaethyleneoxyacrylate, nonylphenoxyoctaethyleneoxyacrylate, nonylphenoxynonaethyleneoxy acrylates, nonylphenoxydecaethyleneoxy acrylate, and nonylphenoxyundecaethyleneoxy acrylate.

Component (B) preferably contains a diacrylate having two acryloyl groups as an acrylate compound from the viewpoint of further improving the balance between pattern formability and peeling properties. More preferably it contains an acrylate.

The (B) component may further contain a methacrylate compound. Examples of methacrylate compounds include methacrylates having a polyhydric alcohol-derived skeleton, methacrylates having a urethane bond, methacrylates having a bisphenol skeleton, methacrylates having an alicyclic skeleton, methacrylates having a phthalic acid skeleton, nonylphenoxypolyethyleneoxymethacrylate, and methacrylic acid alkyl esters. As the methacrylate compound, a compound obtained by changing the acryloyl group of the acrylate compound described above to a methacryloyl group can be used. A methacrylate compound can be used individually by 1 type or in combination of 2 or more types.

The amount of the acrylate compound contained in component (B) is preferably 5% by mass or more, based on the total amount of component (B), from the viewpoint of shortening the resist pattern stripping time, 10% by mass or more, 15% by mass, It may be 80% by mass or more, or 20% by mass or more, and from the viewpoint of improving the resolution of the resist pattern, it is preferably 85% by mass or less, and 80% by mass or less, 75% by mass or less, or 70% by mass or less. may be

((C) photoinitiator)
(C) The photopolymerization initiator (hereinafter also referred to as "component (C)") is not particularly limited as long as it can polymerize the component (B). It can be selected as appropriate. The component (C) may contain a hexaarylbiimidazole derivative or an acridine compound having one or more acridinyl groups in order to improve sensitivity and resolution in a well-balanced manner. (C) Component can be used individually by 1 type or in combination of 2 or more types.

Examples of hexaarylbiimidazole derivatives 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′-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.

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, 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.

The content of component (C) is 0.5 to 10 parts by mass, 1 to 8 parts by mass, or 2 to 5 parts by mass with respect to the total amount of 100 parts by mass of components (A) and (B). may When the content of component (C) is 0.5 parts by mass or more, photosensitivity, resolution and adhesion tend to be improved, and when it is 10 parts by mass or less, resist pattern formability tends to be more excellent.

((D) polymerization inhibitor)
The photosensitive resin film according to the present embodiment can improve the pattern formability by containing (D) a polymerization inhibitor (hereinafter also referred to as "(D) component"). (D) Component can be used individually by 1 type or in combination of 2 or more types.

The component (D) may contain a compound represented by the following formula (I) from the viewpoint of further improving the pattern formability.

In formula (I), R ⁵ is a halogen atom, a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, an amino group, an aryl group, a mercapto group, or a It represents an alkylmercapto group, a carboxylalkyl group having 1 to 10 carbon atoms in the alkyl group, an alkoxy group having 1 to 20 carbon atoms, or a heterocyclic group. m and n are integers selected so that m is an integer of 2 or more, n is an integer of 0 or more, and m+n=6. When n is an integer of ² or more, each R5 may be the same or different. The aryl group may be substituted with an alkyl group having 1 to 20 carbon atoms.

R ⁵ may be a hydrogen atom or an alkyl group having 1 to 20 carbon atoms from the standpoint of further improving compatibility with component (A). The alkyl group having 1 to 20 carbon atoms represented by R ⁵ may be an alkyl group having 1 to 4 carbon atoms. m may be 2 or 3, or may be 2 from the standpoint of further improving resolution.

Examples of compounds represented by the above formula (I) include catechol, 2-methylcatechol, 3-methylcatechol, 4-methylcatechol, 2-ethylcatechol, 3-ethylcatechol, 4-ethylcatechol, 2-propyl catechol, 3-propylcatechol, 4-propylcatechol, 2-n-butylcatechol, 3-n-butylcatechol, 4-n-butylcatechol, 2-tert-butylcatechol, 3-tert-butylcatechol, 4-tert Catechol compounds such as -butylcatechol and 3,5-di-tert-butylcatechol; Resorcinol compounds such as resorcinol, 2-propylresorcinol, 4-propylresorcinol, 2-n-butylresorcinol, 4-n-butylresorcinol, 2-tert-butylresorcinol, 4-tert-butylresorcinol; 1,4-hydroquinone, hydroquinone compounds such as methylhydroquinone, ethylhydroquinone, propylhydroquinone, tert-butylhydroquinone and 2,5-di-tert-butylhydroquinone; and trihydric phenol compounds such as pyrogallol and phloroglucinolone.

The (D) component may contain a catechol compound from the viewpoint of improving resolution. The catechol compounds include 2-methylcatechol, 3-methylcatechol, 4-methylcatechol, 2-ethylcatechol, 3-ethylcatechol, 4-ethylcatechol, 2-propylcatechol, 3-propylcatechol, 4-propylcatechol, 2-n-butylcatechol, 3-n-butylcatechol, 4-n-butylcatechol, 2-tert-butylcatechol, 3-tert-butylcatechol, 4-tert-butylcatechol, 3,5-di-tert- Alkylcatechols such as butylcatechol are preferred, with 3-tert-butylcatechol, 4-tert-butylcatechol, or 3,5-di-tert-butylcatechol being more preferred.

The content of component (D) is 0.010 to 0.30 parts by mass, 0.015 to 0.20 parts by mass, or 0.020 parts by mass based on 100 parts by mass of the total amount of components (A) and (B). It may be up to 0.10 parts by mass. By setting the content of component (D) to 0.30 parts by mass or less, the exposure time can be shortened. By setting the content of the component (D) to 0.010 parts by mass or more, the photoreaction of the photocured portion can be sufficiently advanced, and the pattern formability can be further enhanced.

(other ingredients)
The photosensitive resin composition according to the present embodiment may optionally contain a sensitizer, a dye, a photocoloring agent, a thermal coloration inhibitor, a plasticizer, a pigment, a filler, an antifoaming agent, a flame retardant, and adhesion. Additives such as imparting agents, leveling agents, release accelerators, antioxidants, fragrances, imaging agents, thermal cross-linking agents, and polymerization inhibitors may be further contained. These additives can be used singly or in combination of two or more.

Sensitizers include, for example, dialkylaminobenzophenone compounds, pyrazoline compounds, anthracene compounds, coumarin compounds, xanthone compounds, thioxanthone compounds, oxazole compounds, benzoxazole compounds, thiazole compounds, benzothiazole compounds, triazole compounds, stilbene compounds, and triazine compounds. , thiophene compounds, naphthalimide compounds, triarylamine compounds, and aminoacridine compounds.

From the viewpoint of improving photosensitivity and resolution, the content of the sensitizer is 0.01 to 1 part by mass, 0.02 to 0.02 part by mass, per 100 parts by mass of the total amount of components (A) and (B). It may be 5 parts by weight, 0.03 to 0.2 parts by weight, or 0.04 to 0.1 parts by weight.

Dyes include, for example, malachite green, victoria pure blue, brilliant green, and methyl violet. Photochromic agents include, for example, tribromophenylsulfone, leucocrystal violet, diphenylamine, benzylamine, triphenylamine, diethylaniline, and o-chloroaniline. Plasticizers include, for example, p-toluenesulfonamide.

FIG. 1 is a schematic cross-sectional view showing one embodiment of a photosensitive resin film. The photosensitive resin film 1 according to this embodiment may be formed on the support film 2 using the photosensitive resin composition described above. The photosensitive resin film according to this embodiment can be used in the form of a photosensitive element including a support film 2 and a photosensitive resin film 1 provided on the support film 2 as shown in FIG.

The thickness of the photosensitive resin film 1 is 35-300 μm. The thickness of the photosensitive resin film 1 may be 40 μm or more, 45 μm or more, or 50 μm or more from the viewpoint of forming a wiring pattern with a high aspect ratio. From the viewpoint of peelability of the photosensitive resin film, the thickness of the photosensitive resin film 1 may be 250 μm or less, 200 μm or less, or 150 μm or less.

Examples of the support film 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.

The haze of the support film may be 0.01-5.0%, 0.01-1.5%, 0.01-1.0%, or 0.01-0.5% . Haze refers to a value measured using a commercially available cloudiness meter (turbidity meter) in accordance with the method specified in JIS K7105. Haze can be measured with a commercially available turbidity meter such as NDH-5000 (manufactured by Nippon Denshoku Industries Co., Ltd., trade name).

The thickness of the support film may be 1-200 μm, 1-100 μm, 1-60 μm, 5-60 μm, 10-60 μm, 10-50 μm, 10-40 μm, 10-30 μm, or 10-25 μm. When the thickness of the support film is 1 μm or more, it tends to be possible to suppress the support film from tearing when the support film is peeled off. Further, when the thickness of the support film is 200 μm or less, there is a tendency to easily obtain an economic benefit.

A protective film may be laminated on the surface of the photosensitive resin film 1 opposite to the support film 2 . A polymer film such as polyethylene or polypropylene may be used as the protective film. The same polymer film as the support film may be used, or a different polymer film may be used. It is preferable that the adhesive force between the protective film and the photosensitive resin film 1 is smaller than the adhesive force between the support film 2 and the photosensitive resin film 1 .

The photosensitive resin film 1 can be formed, for example, by applying a photosensitive resin composition onto the support film 2 and then drying it. Coating can be performed using known methods such as roll coating, comma coating, gravure coating, air knife coating, die coating, and bar coating. Drying can be performed at 70 to 150° C. for about 5 to 30 minutes.

When applying the photosensitive resin composition onto the support film 2, if necessary, a solvent may be added to the photosensitive resin composition to use a solution having a solid content of about 30 to 60% by mass. Solvents include, for example, methanol, ethanol, acetone, methyl ethyl ketone, methyl cellosolve, ethyl cellosolve, toluene, N,N-dimethylformamide, and propylene glycol monomethyl ether. A solvent can be used individually by 1 type or in combination of 2 or more types. In this case, the amount of residual solvent in the photosensitive resin film is preferably 2% by mass or less in order to prevent the solvent from diffusing in subsequent steps.

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

On the end face of the roll-shaped photosensitive element, an end face separator may be installed from the viewpoint of end face protection, or a moisture-proof end face separator may be installed from the viewpoint of edge fusion resistance. The photosensitive element may be packaged by wrapping it in a black sheet with low moisture permeability.

Since the photosensitive resin film according to the present embodiment has excellent pattern formability, it is possible to form a resist pattern with a high aspect ratio.

[Method of forming a resist pattern]
The method of forming a resist pattern according to the present embodiment comprises a step of providing a photosensitive layer on a substrate using the photosensitive resin film described above (hereinafter also referred to as a “photosensitive layer forming step”), and at least one step of forming the photosensitive layer. A step of irradiating the part with actinic rays to form a photocured part (hereinafter also referred to as an “exposure step”), and a step of removing at least a part of the photosensitive layer other than the photocured part to form a resist pattern. (hereinafter also referred to as “development step”). A resist pattern can be called a photocured product pattern of a photosensitive resin film, and can be called a relief pattern. Further, the method of forming a resist pattern can also be said to be a method of manufacturing a substrate with a resist pattern.

In the photosensitive layer forming step, when the photosensitive element is used, if the photosensitive element has a protective film, remove it, and then heat the photosensitive resin film to about 70 to 130 ° C. while heating under reduced pressure or at normal temperature. Under reduced pressure, the photosensitive layer is formed on the substrate by pressure-bonding to the substrate at a pressure of about 0.1 to 1 MPa (about 1 to 10 kgf/cm ² ). As the substrate, for example, a copper-clad laminate is used in which a layer made of an insulating material such as a glass fiber reinforced epoxy resin is provided with a copper foil on one side or both sides thereof.

In the exposure step, the support film is removed, or the photosensitive layer is exposed to actinic rays through the support film. Exposure methods include a method of irradiating actinic rays imagewise through a negative or positive mask pattern called artwork (mask exposure method), a method of imagewise irradiating actinic rays by a projection exposure method, LDI (Laser Direct Imaging) exposure method, DLP (Digital Light Processing) exposure method, and other direct drawing exposure methods can be used to imagewise irradiate actinic rays.

As a light source for actinic rays, known light sources can be used. A material that effectively emits ultraviolet rays and visible light is used.

From the viewpoint of improving adhesion, post-exposure baking (PEB: Post exposure bake) may be performed after exposure and before development. The temperature when performing PEB may be 50-100°C. As a heater, a hot plate, a box-type dryer, a heating roll, or the like may be used.

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.

If there is a support film on the photosensitive layer, remove the support film and then remove (develop) the area other than the photocured portion (which can be said to be the unexposed portion). Developing methods include wet development and dry development, and wet development is widely used.

In the case of wet development, development is performed by a known development method using a developer corresponding to the photosensitive resin composition. Examples of the developing method include methods using a dipping method, a paddle method, a spray method, brushing, slapping, scrubbing, rocking immersion, etc. A high-pressure spray method may be used from the viewpoint of improving resolution. Development may be performed by combining two or more of these methods.

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

From the standpoint of safety, stability, and good operability, an alkaline aqueous solution may be used as the developer. The base of the alkaline aqueous solution includes, for example, alkali hydroxides such as lithium, sodium or potassium hydroxide; alkali carbonates such as lithium, sodium, potassium or ammonium carbonates or bicarbonates; potassium phosphate, sodium phosphate alkali metal phosphates such as sodium pyrophosphate, alkali metal pyrophosphates such as potassium pyrophosphate; borax, sodium metasilicate, tetramethylammonium hydroxide, ethanolamine, ethylenediamine, diethylenetriamine, 2-amino-2-hydroxy Methyl-1,3-propanediol, 1,3-diaminopropanol-2, and morpholine.

Examples of alkaline aqueous solutions used for development include 0.1 to 5% by mass sodium carbonate aqueous solution, 0.1 to 5% by mass potassium carbonate aqueous solution, and 0.1 to 5% by mass aqueous sodium hydroxide solution. The pH of the alkaline aqueous solution may be in the range of 9 to 11, and the temperature of the alkaline aqueous solution can be adjusted according to the developability of the photosensitive layer.

For example, a surfactant, an antifoaming agent, and a small amount of organic solvent for promoting development may be mixed in the alkaline aqueous solution. Organic solvents used in the alkaline aqueous solution include, for example, acetone, ethyl acetate, alkoxyethanol 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 may be mentioned. Examples of organic solvents used in organic solvent developers include 1,1,1-trichloroethane, N-methylpyrrolidone, N,N-dimethylformamide, cyclohexanone, methylisobutylketone, and γ-butyrolactone. In order to prevent ignition, the organic solvent may be used as an organic solvent developer by adding water in the range of 1 to 20% by mass.

In the method of forming a resist pattern in the present embodiment, after removing the uncured portion in the development step, heating at about 60 to 250° C. or exposure at about 0.2 to 10 J/cm ² is performed as necessary. may include a step of further hardening the resist pattern.

[Method of forming wiring pattern]
The method for forming a wiring pattern according to the present embodiment includes a step of plating a substrate on which a resist pattern has been formed by the method of forming a resist pattern to form a conductor pattern, and removing the photocured portion after the plating. Have a process.

In the plating process, a resist pattern formed on a substrate with a conductor layer is used as a mask to plate copper, solder, or the like on the conductor layer of the substrate that is not covered with resist. After plating, the resist is removed by removing the resist pattern, which will be described later, and the conductor layer covered with the resist is etched to form a conductor pattern.

The plating method may be electroplating or electroless plating, and electroless plating may be used. Electroless plating includes, for example, copper plating such as copper sulfate plating and copper pyrophosphate plating, solder plating such as high-throw solder plating, Watt bath (nickel sulfate-nickel chloride) plating, nickel plating such as nickel sulfamate plating, Gold plating such as hard gold plating and soft gold plating can be used.

After the plating process, the resist pattern on the substrate is removed. The resist pattern can be removed, for example, with a stronger alkaline aqueous solution than the alkaline aqueous solution used in the developing step. As the strong alkaline aqueous solution, for example, a 1 to 10% by mass sodium hydroxide aqueous solution, a 1 to 10% by mass potassium hydroxide aqueous solution, or the like is used. Among these, a 1 to 5% by mass aqueous sodium hydroxide solution or an aqueous potassium hydroxide solution may be used.

When the resist pattern is removed after plating, the desired printed wiring board can be manufactured by further etching the conductor layer covered with the resist by etching to form a conductor pattern. The etching method at this time is appropriately selected according to the conductor layer to be removed. For example, the etchant described above can be applied.

Methods for removing the resist pattern include, for example, an immersion method and a spray method, which may be used alone or in combination.

FIG. 2 shows one aspect of the process of forming a wiring pattern using the photosensitive resin film according to this embodiment.

In FIG. 2(a), the photosensitive layer 20 is formed by laminating the photosensitive resin film 1 on the substrate 10 in which the conductive layer is formed on the insulating layer by the photosensitive layer forming step. In FIG. 2B, the photosensitive layer 20 is irradiated with actinic rays 30 in the exposure process described above to form a photocured portion in the photosensitive layer 20 . In FIG. 2C, a resist pattern 22, which is a photocured portion, is formed on the substrate 10 by removing regions other than the photocured portion formed by the exposure step from the substrate by a development step. In FIG. 2D, a plating layer 40 is formed on the substrate 10 not covered with the resist by plating using the resist pattern 22 as a mask. In FIG. 2(e), the resist pattern 22, which is the photo-cured portion, is peeled off with a strong alkaline aqueous solution to form a conductor pattern 42. In FIG.

The photosensitive resin film according to the present embodiment has excellent pattern formability even if it is a thick film, and the formed resist pattern has excellent peeling properties. It can be suitably used for

Hereinafter, the purpose and advantages of this embodiment will be described more specifically based on examples and comparative examples, but this embodiment is not limited to the following examples.

[Preparation of photosensitive resin film]
(Examples 1 to 4 and Comparative Example 1)
Each component shown in Table 1 was mixed in the amount shown in the same table (the unit of the numerical value in the table is parts by mass, and in the case of a solution, it is the solid content conversion amount.), and the solution of the photosensitive resin composition was mixed. prepared. Details of each component shown in Table 1 are as follows.

((A) binder polymer)
A-1: Ethylene of methacrylic acid/hydroxyethyl methacrylate/styrene/benzyl methacrylate copolymer (mass ratio: 27/3/50/20, Mw: 35000, acid value: 176 mgKOH/g, Tg: 107°C) Glycol monomethyl ether/toluene solution (solid content: 45% by mass)

(Weight average molecular weight)
120 mg of the binder polymer solution was collected and dissolved in 5 mL of THF to prepare a sample for Mw measurement. Mw was derived by measuring by gel permeation chromatography (GPC) and converting using a standard polystyrene calibration curve. The conditions of GPC are shown below.

(GPC conditions)
Pump: Hitachi L-6000 type (manufactured by Hitachi, Ltd.)
Column: Gelpack GL-R420, Gelpack GL-R430 and Gelpack GL-R440 (manufactured by Showa Denko Materials Co., Ltd., column specifications: 10.7 mmφ × 300 mm)
Eluent: Tetrahydrofuran (hereinafter also referred to as "THF")
Measurement temperature: 40°C
Injection volume: 200 μL
Pressure: 49 kgf/cm ² (4.8 MPa)
Flow rate: 2.05 mL / min Detector: Hitachi L-3300 type RI (manufactured by Hitachi, Ltd.)

(acid value)
An appropriate amount of phenolphthalein solution is added as an indicator to a solution prepared by adding a mixed solvent (mass ratio: toluene/methanol = 70/30) to about 1 g of the binder polymer, and titration is performed with a 0.1N potassium hydroxide aqueous solution. Thus, the acid value of the binder polymer was measured.

((B) photopolymerizable compound)
FA-321A: 2,2-bis (4-(acryloxypentaethoxy) phenyl) propane (Showa Denko Materials Co., Ltd., number of EO groups: 10 (average value))
A-DCP: Tricyclodecanedimethanol diacrylate (Shin-Nakamura Chemical Co., Ltd.)
FA-321M: 2,2-bis (4-(methacryloxypentaethoxy) phenyl) propane (Showa Denko Materials Co., Ltd., number of EO groups: 10 (average value))
FA-024M: polyalkylene glycol dimethacrylate (Showa Denko Materials Co., Ltd., number of EO groups: 12 (average value), number of PO groups: 4 (average value))
BPE-200: Ethoxylated bisphenol A dimethacrylate (modified with EO average 4 mol) (Shin-Nakamura Chemical Industry Co., Ltd.)

((C) photoinitiator)
B-CIM: 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenylbiimidazole (Changzhou Power Electronics New Materials Co., Ltd.)

((D) polymerization inhibitor)
TBC: 4-tert-butyl catechol (DIC Corporation)

(sensitizer)
EAB: (Japan Chemical Industry Co., Ltd.)

(color former)
LCV: Leuco Crystal Violet (Yamada Chemical Industry Co., Ltd.)
(dye)
MKG: Malachite Green (Osaka Organic Chemical Industry Co., Ltd.)
(Adherence imparting agent)
SF-808H: a mixture of carboxybenzotriazole, 5-amino-1H-tetrazole, and methoxypropanol (Sanwa Kasei Co., Ltd.)

A solution of a photosensitive resin composition is uniformly applied onto a polyethylene terephthalate (PET) film (manufactured by Toray Industries, Inc., trade name: FB-40) with a thickness of 16 μm, and dried at 70° C. for 10 minutes using a hot air convection dryer. and dried at 100° C. for 10 minutes to form a photosensitive layer on one side of the PET film as the support film.

[Adhesion]
A copper clad laminate (manufactured by Showa Denko Materials Co., Ltd., trade name “MCL-E-67”) in which copper foil (thickness: 12 μm) is laminated on both sides of a glass fiber reinforced epoxy resin layer is washed with water, pickled and washed with water. It was then dried in an air stream. Then, the copper-clad laminate was heated to 80° C. to laminate a photosensitive resin film on the copper surface of the copper-clad laminate. Lamination was carried out using heat rolls at 110° C. at a pressure of 0.4 MPa and a roll speed of 1.0 m/min. Thus, a laminate was obtained in which the copper-clad laminate, the photosensitive layer and the PET film were laminated in this order.

On the PET film of the laminate, as a negative mask, a 41-step tablet having a density range of 0.00 to 2.00, a density step of 0.05, a tablet size of 20 mm×187 mm, and each step size of 3 mm×12 mm was applied. A photo tool was placed. Then, the photosensitive layer was exposed with a predetermined amount of energy using a parallel light exposure device (manufactured by ORC Manufacturing Co., Ltd., product name "EXM-1201") using a high-pressure mercury lamp as a light source.

On the PET film of the laminate, a photomask PKG R&D Test Pattern No. 2 was applied as a negative for evaluation. 2 (negative for evaluation: having a wiring pattern with a line width/space width of x/250 (x: 2 to 30, unit: μm)), and the number of remaining steps after development of a 41-step tablet was 14. Exposure was performed with an energy amount of 0. After the exposure, the PET film was peeled off, and a 1% by weight sodium carbonate aqueous solution at 30° C. was sprayed for twice the shortest development time (shortest time for removing the unexposed portion) to remove the unexposed portion.

After development processing, the smallest line width/space width value among the resist patterns in which the space portion (unexposed portion) is cleanly removed and the line portion (exposed portion) is formed without meandering or chipping, Adhesion was evaluated. A smaller value means better adhesion.

[Peeling property]
Using a drawing pattern for forming a cured film of 45 mm×60 mm, the photosensitive layer of the laminate was exposed under the same conditions as those for evaluation of adhesion. After the exposure, the PET film was peeled off, and a test piece having a cured film of 45 mm x 60 mm formed on the substrate was prepared by performing development treatment under the same conditions as those used for evaluation of adhesion. Next, 300 mL of a 3.0% by mass sodium hydroxide aqueous solution (stripping solution) at 50° C. was placed in a 400 mL beaker and stirred at 200 revolutions per minute (rpm) using a 30 mm long stirrer. A test piece was immersed in a stripping solution, and the time required for the cured film to completely separate from the substrate was measured. It means that the shorter the peeling time, the better the peeling properties.

1... Photosensitive resin film, 2... Support film, 10... Substrate, 20... Photosensitive layer, 22... Resist pattern, 30... Active ray, 40... Plating layer, 42... Conductor pattern.

Claims

Containing a binder polymer, a photopolymerizable compound containing an acrylate compound, a photopolymerization initiator, and a polymerization inhibitor,
A photosensitive resin film having a thickness of 35 to 300 μm.
The photosensitive resin film according to claim 1, wherein the acrylate compound contains a diacrylate having two acryloyl groups.
The photosensitive resin film according to claim 2, wherein the diacrylate has a bisphenol skeleton or an alicyclic skeleton.
The photosensitive resin film according to any one of claims 1 to 3, wherein the photopolymerizable compound further contains a methacrylate compound.
The photosensitive resin film according to any one of claims 1 to 4, wherein the binder polymer has a structural unit derived from styrene or a styrene derivative.
The photosensitive resin film according to any one of claims 1 to 5, wherein the polymerization inhibitor contains a catechol compound.
A step of providing a photosensitive layer on a substrate using the photosensitive resin film according to any one of claims 1 to 6;
a step of irradiating at least a portion of the photosensitive layer with an actinic ray to form a photocured portion;
removing at least a portion of the photosensitive layer other than the photocured portion to form a resist pattern;
A method of forming a resist pattern, comprising:
forming a conductive pattern by plating the substrate on which the resist pattern is formed by the resist pattern forming method according to claim 7;
A step of removing the photocured portion after the plating process;
A method of forming a wiring pattern, comprising: