KR20230158050A - Photosensitive resin film, method of forming a resist pattern, and method of forming a wiring pattern - Google Patents

Abstract

The present disclosure relates to a photosensitive resin film containing a binder polymer, a photopolymerizable compound containing an acrylate compound, a photopolymerization initiator, and a polymerization inhibitor, and having a thickness of 35 to 300 μm, and formation of a resist pattern using the photosensitive resin film. It relates to a method and a method of forming a wiring pattern.

Description

Photosensitive resin film, method of forming a resist pattern, and method of forming a wiring pattern

This 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 producing conductor patterns. For example, in the manufacture of a wiring board, a resist is formed using a photosensitive resin composition, and then conductor patterns, metal posts, etc. are formed through plating treatment. More specifically, a photosensitive layer is formed on a substrate using a photosensitive resin composition, etc., the photosensitive layer is exposed to light through a predetermined mask pattern, and then the portions where the conductor pattern, metal post, etc. are formed are selectively formed. A resist pattern (resist) is formed by developing so that it can be removed (peeled). Next, a conductor such as copper is formed in the removed portion by plating treatment, and then the resist pattern is removed, thereby producing a wiring board including a conductor pattern, a metal post, etc. (for example, Patent Document 1 and 2).

Patent Document 1: Japanese Patent Publication No. 2000-356852 Patent Document 2: International Publication No. 2008/064803

In electronic components such as inductors, increasing the thickness of the conductor layer to form a wiring pattern with a high aspect ratio, and shortening and shortening each process to improve production efficiency, are being considered. Therefore, the photosensitive resin film is required to be able to form a thick resist pattern and to shorten the peeling time of the formed resist pattern.

The present disclosure has been made in consideration of the above circumstances, and aims to provide a photosensitive resin film capable of achieving both pattern formation and peeling characteristics, a method of forming a resist pattern using the same, and a method of forming a wiring pattern.

The 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.

The method for forming a resist pattern according to the present disclosure includes steps of providing a photosensitive layer on a substrate using the photosensitive resin film described above, and irradiating actinic rays to at least a portion of the photosensitive layer to form a photocured portion. and a step of 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 a step of forming a conductor pattern by plating a substrate on which a resist pattern is formed by the above-described resist pattern forming method, and a step of removing a photocured portion after the plating treatment.

According to the present disclosure, it is possible to provide a photosensitive resin film capable of achieving both pattern formation and peeling characteristics, a method of forming a resist pattern using the same, and a method of forming a wiring pattern.

1 is a schematic cross-sectional view showing one embodiment of a photosensitive resin film.
FIG. 2 is a diagram schematically showing one aspect of a process for forming a wiring pattern.

Hereinafter, the present disclosure will be described in detail. In this specification, the numerical range indicated using “~” indicates a range that includes the numerical values written before and after “~” as the minimum and maximum values, respectively. In addition, in the numerical range described in stages in this specification, the upper or lower limit of the numerical range at a certain level may be replaced with the upper or lower limit of the numerical range at another level. In the numerical range described in this specification, the upper or lower limit of the numerical range may be replaced with the value shown in the examples.

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

In this specification, “solid content” refers to the non-volatile content excluding volatile substances such as water and solvent contained in the photosensitive resin composition, and refers to the component that remains without volatilizing when the resin composition is dried, and is stored at 25°C. It also includes those in liquid form, starch syrup form, and wax form at around room temperature.

[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. Hereinafter, each component used in the photosensitive resin film and photosensitive resin composition will be described in detail.

((A) Binder polymer)

(A) The binder polymer (hereinafter also referred to as “component (A)”) 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, benzyl (meth)acrylic acid, alkyl (meth)acrylic acid, and tetrahydro (meth)acrylic acid. Acrylamides such as furfuryl ester, (meth)acrylic acid dimethylaminoethyl ester, (meth)acrylic acid diethylaminoethyl ester, (meth)acrylic acid glycidyl ester, and diacetone acrylamide, acrylonitrile, and alkylvinyl. ter, 2,2,2-trifluoroethyl (meth)acrylate, and 2,2,3,3-tetrafluoropropyl (meth)acrylate. Polymerizable monomers can be used individually or in combination of two or more types.

Component (A) may have a structural unit based on styrene or a styrene derivative from the viewpoint of adhesion and peeling characteristics. Styrene derivatives are polymerizable compounds in which the hydrogen atom in the α position or aromatic ring of styrene, such as vinyl toluene or α-methylstyrene, is substituted. Component (A) can be produced, for example, by radically polymerizing a polymerizable monomer containing styrene or a styrene derivative and other polymerizable monomers.

The content of the structural unit based on styrene or a styrene derivative in the component (A) may be 15 to 64 mass%, 25 to 60 mass%, 35 to 55 mass%, or 45 to 50 mass%. When the content of structural units based on styrene or styrene derivatives is 15% by mass or more, adhesion tends to improve, and when it is 64% by mass or less, the growth of peeling pieces during development can be suppressed and is not required for peeling. There is a tendency to suppress the lengthening of the time spent doing it.

(A) Component may have a carboxy group from the viewpoint of alkaline developability. Examples of polymerizable monomers having a carboxyl group include (meth)acrylic acid, α-bromoacrylic acid, α-chloroacrylic acid, β-furyl (meth)acrylic acid, β-styryl (meth)acrylic acid, and maleic acid. , maleic acid monoesters such as maleic acid anhydride, monomethyl maleate, monoethyl maleate, and monoisopropyl maleate, fumaric acid, cinnamic acid, α-cyanocinnamic acid, itaconic acid, crotonic acid, and propiolic acid. You can. From the viewpoint of further improving alkali developability, the polymerizable monomer having a carboxy group may be (meth)acrylic acid or methacrylic acid.

In order to improve alkali developability and alkali resistance with a good balance, the content of the structural unit based on a polymerizable monomer having a carboxyl group is 10 to 50% by mass, 15 to 40%, based on the total amount of component (A). It may be mass%, or 20 to 35 mass%. When the content of structural units based on polymerizable monomers having a carboxyl group is 10% by mass or more, alkali developability tends to improve, and when it is 50% by mass or less, alkali resistance tends to be excellent.

(A) The component may have a hydroxyl group from the viewpoint of segmentation of the peeled piece. Examples of polymerizable monomers having a hydroxyl group include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and 2-hydroxybutyl. Hydroxyl group-containing (meth)acrylates such as (meth)acrylate, 3-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.

In order to improve pattern formation and peeling properties with a good balance, the content of the structural unit based on a polymerizable monomer having a hydroxyl group is 0.5 to 15% by mass, 1 to 10%, based on the total amount of component (A). It may be mass%, or 2-5 mass%.

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

Component (A) may have a structural unit based on (meth)acrylic acid alkyl ester from the point of improving the reversibility of the resist pattern. Examples of alkyl (meth)acrylate include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, and (meth)acrylate. ) heptyl acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, undecyl (meth)acrylate, and dodecyl (meth)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 170 in order to further improve the balance of developability, resolution, and peeling characteristics. It may be ~190mgKOH/g.

The weight average molecular weight (Mw) of the 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 component (A) is 10,000 or more, there is a tendency for the photocured portion to have excellent developer resistance, and when it is 100,000 or less, there is a tendency to suppress the development time for the unexposed portion from being prolonged. (A) Component may have a dispersion degree (weight average molecular weight/number average molecular weight) of 1.0 to 3.0 or 1.0 to 2.0. As the degree of dispersion decreases, resolution tends to improve.

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

(A) Component can be used individually or in combination of 2 or more types. Component (A) when two or more types are used in combination include, for example, two or more binder polymers made of different polymerizable monomers, two or more binder polymers with different Mw, and two or more types of binder polymers with different dispersions. A binder polymer may be mentioned.

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 60 parts by mass, based on 100 parts by mass of the total amount of component (A) and component (B) described later. It can also be granted. When the content of component (A) is within this range, the strength of the photocured portion of the photosensitive resin film and the photosensitive layer becomes better.

((B) Photopolymerizable compound)

(B) By containing an acrylate compound as the photopolymerizable compound (hereinafter also referred to as “component (B)”), the photosensitive resin film can form a thick resist pattern with excellent adhesion during development, The peeling time of the formed resist pattern can be shortened. Since the acryloyl group does not have a methyl group, its hydrophobicity is lower than that of the methacryloyl group, and there is no steric hindrance due to the methyl group, the present inventors speculate that the resist pattern becomes easier to remove with a stripper.

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 with a polyhydric alcohol-derived skeleton, acrylates with a urethane bond, acrylates with a bisphenol skeleton, acrylates with an alicyclic skeleton, acrylates with a phthalic acid skeleton, Nonylphenoxypolyethyleneoxyacrylate, and acrylic acid alkyl ester can be mentioned. Acrylate compounds can be used individually or in combination of two or more types.

Acrylates having a skeleton derived from polyhydric alcohol include, for example, polyalkylene glycol diacrylate, trimethylolpropane diacrylate, trimethylolpropane triacrylate, and EO-modified trimethylolpropane triacrylate. Acrylates, PO-modified trimethylolpropane triacrylate, EO, PO-modified trimethylolpropane triacrylate, tetramethylolmethane triacrylate, tetramethylolmethanetetraacrylate, and dipentaerythritol. Alternatively, an acrylate having a skeleton derived from pentaerythritol can be mentioned. “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.

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 polyalkylene glycol diacrylate having both an EO group and a PO group, the EO group and the PO group may each exist continuously in a block form or may exist randomly. Additionally, the PO group may be either an oxy-n-propylene group or an oxyisopropylene group. Additionally, in the (poly)oxyisopropylene group, the secondary carbon of the propylene group may be bonded to an oxygen atom, or the primary carbon may be bonded to an oxygen atom.

Acrylates having a urethane bond include, for example, acrylic monomers having an OH group on β and diisocyanates (isophorone diisocyanate, 2,6-toluene diisocyanate, 2,4 -Addition reactants of (toluene diisocyanate, 1,6-hexamethylene diisocyanate, etc.), tris (acryloxytetraethylene glycol isocyanate) hexamethylene isocyanurate, EO modified urethane Examples include indiacrylate and EO, PO modified urethane diacrylate.

Acrylates having a bisphenol skeleton include, for example, 2,2-bis(4-(acryloxypolyethoxy)phenyl)propane and 2,2-bis(4-(acryloxypolypropoxy)phenyl)propane. Payne, 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 preferred because it further improves pattern formation properties.

As an acrylate having an alicyclic skeleton, an acrylate having an alicyclic hydrocarbon group having 5 to 20 carbon atoms can be used. Examples of the alicyclic skeleton include cyclopentane, cyclohexane, cyclooctane, cyclodecane, norbornene, dicyclopentane, and tricyclodecane. Among these, the acrylate compound may be an acrylate having a tricyclodecane skeleton in order to further improve the peeling properties. Acrylates having an alicyclic skeleton include, for example, dicyclopentenyl acrylate, dicyclopentenyl acrylate, dicyclopentenyloxyethyl acrylate, cyclohexyl acrylate, cyclohexyl diacrylate, and tricyclopentenyl acrylate. Decane dimethanol diacrylate can be mentioned. Examples of commercially available products of tricyclodecane dimethanol diacrylate include A-DCP (tricyclodecane dimethanol diacrylate, manufactured by Shinnakamura Chemical Industry Co., Ltd.).

Acrylates having a phthalic acid skeleton include, for example, γ-chloro-β-hydroxypropyl-β'-acryloyloxyethyl-o-phthalate, β-hydroxyethyl-β'-acryloyloxyethyl- o-phthalate, and β-hydroxypropyl-β'-acryloyloxyethyl-o-phthalate.

Nonylphenoxypolyethyleneoxyacrylate includes, for example, nonylphenoxytetraethyleneoxyacrylate, nonylphenoxypentaethyleneoxyacrylate, nonylphenoxyhexaethyleneoxyacrylate, nonylphenoxyheptaethyleneoxyacrylate, and nonylphenoxyheptaethyleneoxyacrylate. Examples include phenoxyoctaethyleneoxyacrylate, nonylphenoxynonaethyleneoxyacrylate, nonylphenoxydecaethyleneoxyacrylate, and nonylphenoxyundecaethyleneoxyacrylate.

In order to further improve the balance between pattern formation and peeling properties, the component (B) preferably contains a diacrylate having two acryloyl groups as an acrylate compound, and has a bisphenol skeleton or an alicyclic skeleton. It is more preferable to include diacrylate.

(B) Component may further contain a methacrylate compound. Examples of methacrylate compounds include methacrylate with a polyhydric alcohol-derived skeleton, methacrylate with a urethane bond, methacrylate with a bisphenol skeleton, methacrylate with an alicyclic skeleton, and phthalic acid skeleton. Examples include methacrylate, nonylphenoxypolyethyleneoxymethacrylate, and methacrylic acid alkyl ester. As a methacrylate compound, a compound obtained by changing the acryloyl group of the above-mentioned acrylate compound to a methacryloyl group can be used. Methacrylate compounds can be used individually or in combination of two or more types.

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

((C) Photopolymerization initiator)

(C) The photopolymerization initiator (hereinafter also referred to as "component (C)") is not particularly limited as long as it can polymerize component (B), and can be appropriately selected from commonly used photopolymerization initiators. Component (C) may contain a hexaarylbiimidazole derivative or an acridine compound having one or more acridinyl groups in order to improve sensitivity and resolution with a good balance. (C) Component can be used individually 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)-diphenyl Biimidazole, 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)- and 4,4',5,5'-tetrakis-(3-methoxyphenyl)-biimidazole.

Examples of acridine compounds include 9-phenylacridine, 9-(p-methylphenyl)acridine, 9-(m-methylphenyl)acridine, and 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-acrylate) dinyl)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 may be mentioned.

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

((D) Polymerization inhibitor)

The photosensitive resin film according to this embodiment can improve pattern formation by containing (D) a polymerization inhibitor (hereinafter also referred to as "component (D)"). (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 pattern formation properties.

[Formula 1]

In formula (I), R ⁵ is a halogen atom, a hydrogen atom, an alkyl group with 1 to 20 carbon atoms, a cycloalkyl group with 3 to 10 carbon atoms, an amino group, an aryl group, a mercapto group, an alkylmercapto group with 1 to 10 carbon atoms, The alkyl group represents a carboxyl alkyl group having 1 to 10 carbon atoms, 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, R ⁵ may be the same or different. Additionally, 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 viewpoint 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. From the viewpoint of further improving resolution, m may be 2 or 3, or may be 2.

Compounds represented by the general formula (I) include, for example, catechol, 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- Catechol compounds such as butylcatechol, 3-tert-butylcatechol, 4-tert-butylcatechol, and 3,5-di-tert-butylcatechol; Resorcinol (Resorcinol), 2-methylresorcinol, 4-methylresorcinol, 5-methylresorcinol (Orsine), 2-ethylresorcinol, 4-ethylresorcinol, 2-propylreso Resorcinol such as cinol, 4-propylresorcinol, 2-n-butylresorcinol, 4-n-butylresorcinol, 2-tert-butylresorcinol, and 4-tert-butylresorcinol compound; Hydroquinone compounds such as 1,4-hydroquinone, methylhydroquinone, ethylhydroquinone, propylhydroquinone, tert-butylhydroquinone, and 2,5-di-tert-butylhydroquinone; and trihydric phenol compounds such as pyrogallol and phloroglucinol.

(D) Component may contain a catechol compound since it improves resolution. Catechol compounds include 2-methylcatechol, 3-methylcatechol, 4-methylcatechol, 2-ethylcatechol, 3-ethylcatechol, 4-ethylcatechol, 2-propylcatechol, and 3-propylcatechol. Catechol, 4-propylcatechol, 2-n-butylcatechol, 3-n-butylcatechol, 4-n-butylcatechol, 2-tert-butylcatechol, 3-tert-butylcatechol, 4 Alkylcatechols such as -tert-butylcatechol and 3,5-di-tert-butylcatechol are preferred, and 3-tert-butylcatechol, 4-tert-butylcatechol, or 3,5-di- tert-butylcatechol is more preferred.

The content of component (D) may be 0.010 to 0.30 parts by mass, 0.015 to 0.20 parts by mass, or 0.020 to 0.10 parts by mass with respect to 100 parts by mass of the total amount of component (A) and component (B). By setting the content of the component (D) to 0.30 parts by mass or less, the exposure time can be shortened. By setting the content of component (D) to 0.010 parts by mass or more, the photoreaction in the photocurable portion can sufficiently proceed and pattern formation can be further improved.

(Other ingredients)

The photosensitive resin composition according to the present embodiment may contain, if necessary, a sensitizer, dye, photochromic agent, anti-chromic agent, plasticizer, pigment, filler, anti-foaming agent, flame retardant, adhesion imparting agent, leveling agent, peeling accelerator, antioxidant, and fragrance. , it may further contain additives such as an imaging agent, a thermal crosslinking agent, and a polymerization inhibitor. These additives can be used individually or in combination of two or more types.

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

In terms of improving photosensitivity and resolution, the content of the sensitizer is 0.01 to 1 part by mass, 0.02 to 0.5 part by mass, 0.03 to 0.2 part by mass, based on 100 parts by mass of the total amount of component (A) and component (B). Alternatively, 0.04 to 0.1 mass may be assigned.

Examples of dyes include malachite green, Victoria pure blue, brilliant green, and methyl violet. Examples of photochromic agents include tribromophenyl sulfone, leuco crystal violet, diphenylamine, benzylamine, triphenylamine, diethylaniline, and o-chloroaniline. Examples of the plasticizer include p-toluenesulfonamide.

1 is a schematic cross-sectional view showing one embodiment of a photosensitive resin film. The photosensitive resin film 1 according to the present 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 provided with a support film 2 and a photosensitive resin film 1 provided on the support film 2, as shown in FIG. 1.

The thickness of the photosensitive resin film 1 is 35 to 300 μm. From the viewpoint of forming a wiring pattern with a high aspect ratio, 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 the 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. can be mentioned.

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

The thickness of the support film may be 1 to 200 μm, 1 to 100 μm, 1 to 60 μm, 5 to 60 μm, 10 to 60 μm, 10 to 50 μm, 10 to 40 μm, 10 to 30 μm, or 10 to 25 μm. When the thickness of the support film is 1 μm or more, tearing of the support film tends to be suppressed when peeling off the support film. Additionally, when the thickness of the support film is 200 μm or less, it tends to be easy to obtain economic benefits.

A protective film may be laminated on the surface of the photosensitive resin film 1 opposite to the support film 2. As a protective film, a polymer film such as polyethylene or polypropylene may be used. 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 the photosensitive resin composition on the support film 2 and then drying it. Application can be performed using known methods such as roll coat, comma coat, gravure coat, air knife coat, die coat, and bar coat, for example. Drying can be performed at 70 to 150°C for about 5 to 30 minutes.

When applying the photosensitive resin composition on the support film 2, a solvent may be added to the photosensitive resin composition as needed, and a solution having a solid content of about 30 to 60% by mass may be used. Examples of solvents include methanol, ethanol, acetone, methyl ethyl ketone, methyl cellosolve, ethyl cellosolve, toluene, N,N-dimethylformamide, and propylene glycol monomethyl ether. there is. Solvents can be used individually or in combination of two or more types. In this case, the amount of residual solvent in the photosensitive resin film is preferably 2% by mass or less to prevent diffusion of the solvent in subsequent processes.

The form of the photosensitive element is not particularly limited. For example, it may be in the form of a sheet or may be wound in a roll shape around a core. When winding up in roll shape, you may wind up so that the support film faces the outside. Examples of the winding core include plastic such as polyethylene resin, polypropylene resin, polystyrene resin, polyvinyl chloride resin, or ABS resin (acrylonitrile-butadiene-styrene copolymer).

A single-sided separator may be provided on the end face of the roll-shaped photosensitive element from the point of view of end-face protection, or a moisture-proof end-side separator may be provided from the point of view of edge fusion resistance. The photosensitive element may be wrapped and packaged in a black sheet with low moisture permeability.

Since the photosensitive resin film according to this embodiment has excellent pattern formation properties, it can form a resist pattern with a high aspect ratio.

[Method of forming resist pattern]

The resist pattern forming method according to the present embodiment includes 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 a portion of the photosensitive layer. A process of forming a photocured portion by irradiating actinic rays (hereinafter also referred to as “exposure process”), and a process of forming a resist pattern by removing at least part of the photosensitive layer other than the photocured portion (hereinafter referred to as “development process”). Also referred to as “process”). A resist pattern can be referred to as a photocured product pattern of a photosensitive resin film, and can also be referred to as a relief pattern. Additionally, the method of forming a resist pattern can also be referred to as a method of manufacturing a substrate containing a resist pattern.

In the photosensitive layer formation process, when using the photosensitive element, if the photosensitive element has a protective film, this is removed, and then the photosensitive resin film is heated to about 70 to 130°C, and 0.1 to 1 MPa is applied to the substrate under reduced or normal pressure. A photosensitive layer is formed on the substrate by pressing and stacking with a pressure of about 1 to 10 kgf/cm ² . As a substrate, for example, a copper-clad laminate in which copper foil is provided on one or both sides of a layer made of an insulating material such as glass fiber reinforced epoxy resin is used.

In the exposure process, the support film is removed, or the photosensitive layer is exposed to actinic light through the support film. Exposure methods include a method of irradiating actinic rays in an image shape through a negative or positive mask pattern called artwork (mask exposure method), a method of irradiating actinic rays in an image shape by a projection exposure method, and LDI (Laser Direct Imaging). ) A method of irradiating actinic rays in the form of an image by a direct drawing exposure method such as an exposure method or a DLP (Digital Light Processing) exposure method is included.

As a light source of actinic light, a known light source can be used, for example, a carbon arc lamp, a mercury vapor arc lamp, a high-pressure mercury lamp, a xenon lamp, a gas laser such as an argon laser, a solid laser such as a YAG laser, a semiconductor laser, etc. Those that effectively radiate ultraviolet rays and visible light are used.

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

In the development process, at least part of the photosensitive layer other than the photocured portion is removed from the substrate, thereby forming a resist pattern on the substrate.

When a support film is present on the photosensitive layer, the support film is removed, and then removal (development) of areas other than the photocured portion (which may also be referred to as unexposed portion) is performed. There are two developing methods: wet development and dry development, but wet development is widely used.

In the case of wet development, development is performed by a known developing method using a developing solution corresponding to the photosensitive resin composition. Development methods include methods using a dip method, puddle method, spray method, brushing, slapping, scrubbing, oscillation immersion, etc., and in order to improve resolution, a high pressure spray method may be used. Development may be performed by combining two or more of these methods.

The composition of the developer is appropriately selected depending on the composition of the photosensitive resin composition. Examples of developing solutions include alkaline aqueous solutions and organic solvent developing solutions.

From the standpoint of safety, stability, and good operability, an alkaline aqueous solution may be used as a developer. Examples of the base of the alkaline aqueous solution include alkali hydroxides such as hydroxides of lithium, sodium, or potassium; Alkali carbonates such as carbonates or bicarbonates of lithium, sodium, potassium or ammonium; Alkali metal phosphates such as potassium phosphate and sodium phosphate; Alkali metal pyrophosphates such as sodium pyrophosphate and potassium pyrophosphate; Borax, sodium metasilicate, tetramethylammonium hydroxide, ethanolamine, ethylenediamine, diethylenetriamine, 2-amino-2-hydroxymethyl-1,3-propanediol, 1,3-diaminopropanol- 2, and morpholine.

Examples of alkaline aqueous solutions used for development include 0.1 to 5% by mass aqueous sodium carbonate solution, 0.1 to 5% by mass aqueous potassium carbonate 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.

The alkaline aqueous solution may contain, for example, a surface active agent, an antifoaming agent, or a small amount of an organic solvent to promote development. Organic solvents used in alkaline aqueous solutions include, for example, acetone, ethyl acetate, alkoxyethanol having an alkoxy group of 1 to 4 carbon atoms, ethyl alcohol, isopropyl alcohol, butyl alcohol, diethylene glycol monomethyl ether, and dimethyl alcohol. Examples include ethylene glycol monoethyl ether and diethylene glycol monobutyl ether. Organic solvents Examples of organic solvents used in the developer include 1,1,1-trichloroethane, N-methylpyrrolidone, N,N-dimethylformamide, cyclohexanone, methylisobutylketone, and Examples include γ-beutyrolactone. To prevent ignition, water may be added to the organic solvent in a range of 1 to 20% by mass to form an organic solvent developer.

In the resist pattern formation method in this embodiment, after removing the uncured portion in the development process, heating at about 60 to 250°C or exposure at about 0.2 to 10 J/cm ² is performed as necessary. A step of further hardening the resist pattern may be included.

[Method of forming wiring pattern]

The method of forming a wiring pattern according to the present embodiment includes a step of forming a conductor pattern by plating a substrate on which a resist pattern is formed by the above-described resist pattern forming method, and a step of removing a photocured portion after the plating treatment. .

In the plating process, copper, solder, etc. are plated on the conductor layer of the substrate that is not covered with the resist, using the resist pattern formed on the substrate with the conductor layer as a mask. After the plating treatment, the resist is removed by removing the resist pattern described later, and the conductor layer covered by the resist is further etched to form a conductor pattern.

As a method of plating treatment, electrolytic plating treatment or electroless plating treatment may be used, but among these, electroless plating treatment may be used. Electroless plating treatments include, for example, copper plating such as copper sulfate plating and copper pyrophosphate plating, solder plating such as high-slow solder plating, Watt bath (nickel sulfate-nickel chloride) plating, and nickel sulfa nitrate. Gold plating such as nickel plating, hard gold plating, and soft gold plating can be mentioned.

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

When the resist pattern is removed after performing the plating treatment, the conductor layer covered with the resist is further etched by an etching process to form a conductor pattern, thereby producing the desired printed wiring board. The etching method at this time is appropriately selected depending on the conductor layer to be removed. For example, the etching solution described above can be applied.

Examples of resist pattern removal methods include an immersion method and a spray method, and these may be used individually or in combination.

One aspect of the process of forming a wiring pattern using the photosensitive resin film according to this embodiment is shown in FIG. 2.

In Figure 2 (a), the photosensitive layer 20 is formed by laminating the photosensitive resin film 1 on the substrate 10 on which the conductor layer is formed on the insulating layer through the photosensitive layer forming process. In Figure 2 (b), through the exposure process, actinic rays 30 are irradiated onto the photosensitive layer 20, and a photocured portion is formed on the photosensitive layer 20. In FIG. 2(c) , a resist pattern 22, which is a photocurable portion, is formed on the substrate 10 by removing areas other than the photocured portion formed through the exposure process from the substrate through the development process. In Figure 2(d), the plating layer 40 is formed on the substrate 10 not covered with resist by plating using the resist pattern 22 as a mask. In Figure 2(e), the resist pattern 22, which is a photocurable portion, is peeled off with a strong alkali aqueous solution to form a conductor pattern 42.

The photosensitive resin film according to the present embodiment has excellent pattern formation properties even if it is a thick film, and the formed resist pattern has excellent peeling properties, so it can be suitably used, for example, in the production of electronic circuit boards such as inductors.

Example

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

[Production of photosensitive resin film]

(Examples 1 to 4 and Comparative Example 1)

Each component shown in Table 1 was mixed in the mixing amount shown in the same table (the unit of the numerical value in the table is mass part, and in the case of a solution, it is the amount converted to solid content) to prepare a solution of the photosensitive resin composition. The details of each component shown in Table 1 are as follows.

((A) Binder polymer)

A-1: Copolymer of methacrylic acid/hydroxyethyl methacrylate/styrene/benzyl methacrylate (mass ratio: 27/3/50/20, Mw: 35000, acid value: 176mgKOH/g, Tg: 107°C ) ethylene 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 measured by gel permeation chromatography (GPC) and derived by conversion using a standard polystyrene calibration curve. The conditions of GPC are shown below.

(GPC conditions)

Pump: Hitachi L-6000 type (made by Hitachi Seisakusho Co., Ltd.)

Column: Gelpack GL-R420, Gelpack GL-R430 and Gelpack GL-R440 (manufactured by Showa Denko Materials Co., Ltd., column specifications: 10.7 mm ϕ × 300 mm)

Eluent: Tetrahydrofuran (hereinafter also referred to as “THF”)

Measurement temperature: 40℃

Injection volume: 200μL

Pressure: 49Kgf/ ^cm2 (4.8MPa)

Flow rate: 2.05mL/min

Detector: Hitachi L-3300 type RI (made by Hitachi Seisakusho Co., Ltd.)

(acid value)

The acid value of the binder polymer was determined by adding an appropriate amount of phenolphthalein solution as an indicator to a solution obtained by dissolving a mixed solvent (mass ratio: toluene/methanol = 70/30) in about 1 g of the binder polymer and titrating with a 0.1 N aqueous potassium hydroxide solution. 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 (Shinnakamura Kagaku High School 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 (EO average 4 mol modified) (Shinnakamura Kagaku Kogyo Co., Ltd.)

((C) Photopolymerization initiator)

B-CIM: 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenylbiimidazole (Changzhou Strong Electronic New Materials Co., Ltd.)

((D) Polymerization inhibitor)

TBC: 4-tert-butylcatechol (DIC Corporation)

(Sensitizer)

EAB: (Nippon Kagaku Kogyosho Co., Ltd.)

(Coloring agent)

LCV: Ryuko Crystal Violet (Yamada Kagaku High School Co., Ltd.)

(dyes)

MKG: Malachite Green (Osaka Yuki Kagaku High School Co., Ltd.)

(Adhesion granting agent)

SF-808H: mixture of carboxybenzotriazole, 5-amino-1H-tetrazole, and methoxypropanol (Sanwa Kasei Co., Ltd.)

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

[Adhesion]

A copper-clad laminate (manufactured by Showa Kogyo Materials Co., Ltd., product 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, pickled, and washed with air. dried with Next, the copper-clad laminate was heated to 80°C, and a photosensitive resin film was laminated on the copper surface of the copper-clad laminate. Lamination was performed using a heat roll at 110°C, a compression 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 PET film were laminated in this order.

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

On the PET film of the laminate, photomask PKG R&D Test Pattern No. was applied as a negative for evaluation. 2 (negative for evaluation: a line width/space width of x/250 (x: 2 to 30, unit: μm) with a wiring pattern) is used, and the number of remaining steps after development of the 41-step tablet is 14.0. Exposure was performed with different amounts of energy. After exposure, the PET film was peeled, and a 1 mass% 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, the space portion (unexposed portion) is removed cleanly, and the line portion (exposed portion) is formed without meandering or omission by the smallest line width/space width value. , adhesion was evaluated. The smaller this value, the better the adhesion.

[Peeling characteristics]

Using a drawing pattern that forms a cured film of 45 mm x 60 mm, the photosensitive layer of the laminated body was exposed under the same conditions as for evaluation of adhesiveness. After exposure, the PET film was peeled off and development was performed under the same conditions as for the evaluation of adhesion, thereby producing a test piece with a cured film of 45 mm x 60 mm on the substrate. Next, 300 mL of 3.0% by mass sodium hydroxide aqueous solution (stripping solution) at 50°C was added to a beaker with a capacity of 400 mL, and the mixture was stirred at 200 revolutions/minute (rpm) using a stirrer with a length of 30 mm. The test piece was immersed in the stripping liquid, and the time until the cured film completely separated from the substrate was measured. A shorter peeling time means better peeling characteristics.

[Table 1]

One… photosensitive resin film
2… support film
10… Board
20… photosensitive layer
22… resist pattern
30… active rays
40… plating layer
42… conductor pattern

Claims (8)

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