Photosensitive resin composition, photosensitive element, method for forming resist pattern, and method for manufacturing printed wiring board

Abstract

This photosensitive resin composition contains a binder polymer containing structural units derived from a (meth)acrylate compound having a dicyclopentanyl group, a photopolymerizable compound, a photopolymerization initiator, a sensitizer having absorption at 340-430 nm, and a UV absorbent, wherein the UV absorbent has a molar light absorption coefficient within the range 500-50000 L / (mol*cm) for 365 nm wavelength light.

Description

[Technical field]

[0001] The present invention relates to a photosensitive resin composition, a photosensitive element, a method for forming a resist pattern, and a method for producing a printed wiring board. [Background technology]

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

[0003] When a printed wiring board is manufactured using a photosensitive element, first, the photosensitive layer of the photosensitive element is laminated on a circuit-forming substrate. Next, a predetermined portion of the photosensitive layer is irradiated with active light rays to harden the exposed portion. After that, the support is peeled off and removed, and the unexposed portion of the photosensitive layer is removed with a developer to form a resist pattern on the substrate. Next, using this resist pattern as a mask, the substrate on which the resist pattern is formed is subjected to an etching process or a plating process to form a circuit pattern on the substrate, and finally, the hardened portion of the photosensitive layer (resist pattern) is peeled off and removed from the substrate.

[0004] The exposure method involves exposing the photosensitive layer to a pattern through a mask film or the like. In recent years, the projection exposure method has come into use, in which the photosensitive layer is exposed by irradiating it with active light projected from an image of a photomask through a lens. Ultra-high pressure mercury lamps are used as the light source for the projection exposure method. Generally, exposure machines that use monochromatic i-line light (365 nm) as the exposure wavelength are widely used, but monochromatic h-line light (405 nm) and IHG mixed line exposure wavelengths may also be used.

[0005] The projection exposure method is an exposure method that can ensure higher resolution and higher alignment than the contact exposure method, and therefore has attracted much attention in the current situation where there is a demand for finer circuit formation on printed wiring boards.

[0006] With the recent trend toward high density printed wiring boards, there is an increasing demand for photosensitive resin compositions with excellent resolution and adhesion. In particular, in the manufacture of package substrates, there is a demand for photosensitive resin compositions capable of forming resist patterns with a line width / space width of 10 / 10 (unit: μm) or less. For example, Patent Document 1 discusses the use of a specific photopolymerizable compound to improve resolution and adhesion. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2013-195712 A Summary of the Invention [Problem to be solved by the invention]

[0008] However, in recent years, conductor patterns have become increasingly finer, and it is desired that the photosensitive resin composition be used to form even finer resist patterns in which the line width and space width are both 5 μm or less, and even more preferably the line width and space width are both 1 μm or less.

[0009] The present disclosure has been made in consideration of the problems associated with the above-mentioned conventional techniques, and has an object to provide a photosensitive resin composition that is excellent in resolution and adhesion and is capable of forming a fine resist pattern, a photosensitive element that uses the same, a method for forming a resist pattern, and a method for producing a printed wiring board. [Means for solving the problem]

[0010] One aspect of the present disclosure relates to a photosensitive resin composition comprising a binder polymer including a structural unit derived from a (meth)acrylate compound having a dicyclopentanyl group, a photopolymerizable compound, a photopolymerization initiator, a sensitizer having absorption at 340 to 430 nm, and an ultraviolet absorber, wherein the molar absorption coefficient of the ultraviolet absorber for light with a wavelength of 365 nm is in the range of 500 to 50,000 L / (mol cm).

[0011] Another aspect of the present disclosure relates to a photosensitive element including a support and a photosensitive layer formed on the support using the above-mentioned photosensitive resin composition.

[0012] Another aspect of the present disclosure relates to a method for forming a resist pattern, comprising: a photosensitive layer forming step of laminating a photosensitive layer containing the above-mentioned photosensitive resin composition or a photosensitive layer of the above-mentioned photosensitive element on a substrate; an exposure step of irradiating a predetermined portion of the photosensitive layer with active light to form a photocured portion; and a development step of removing an area of ​​the photosensitive layer other than the predetermined portion from the substrate.

[0013] Another aspect of the present disclosure relates to a method for producing a printed wiring board, including a step of etching or plating a substrate on which a resist pattern has been formed by the above-described method for forming a resist pattern, to form a conductor pattern. Effect of the Invention

[0014] According to the present disclosure, it is possible to provide a photosensitive resin composition that is excellent in resolution and adhesion and is capable of forming a fine resist pattern, a photosensitive element that uses the same, a method for forming a resist pattern, and a method for producing a printed wiring board. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, the embodiment for carrying out the present disclosure will be described in detail. However, the present disclosure is not limited to the following embodiment. In this specification, the term "process" includes not only an independent process, but also a process that cannot be clearly distinguished from other processes, as long as the intended effect of the process is achieved. In this specification, the term "layer" includes a structure having a shape formed on the entire surface as well as a structure having a shape formed on a part of the surface when observed in a plan view. In this specification, "(meth)acrylic acid" means at least one of "acrylic acid" and the corresponding "methacrylic acid". The same applies to other similar expressions such as (meth)acrylate.

[0016] In this specification, a numerical range indicated using "~" indicates a range including the numerical values ​​before and after "~" as the minimum and maximum values, respectively. In the numerical ranges described in stages in this specification, the upper limit or lower limit of a certain numerical range may be replaced with the upper limit or lower limit of a numerical range of another stage. In addition, in the numerical ranges described in this specification, the upper limit or lower limit of the numerical range may be replaced with a value shown in the examples.

[0017] In this specification, when referring to the amount of each component in a composition, if multiple substances corresponding to each component are present in the composition, the amount refers to the total amount of those multiple substances present in the composition, unless otherwise specified.

[0018] [Photosensitive resin composition] The photosensitive resin composition of the present embodiment contains (A) component: a binder polymer containing a structural unit derived from a (meth)acrylate compound having a dicyclopentanyl group, (B) component: a photopolymerizable compound, (C) component: a photopolymerization initiator, (D) component: a sensitizer having absorption at 340 nm to 430 nm, and (E) component: an ultraviolet absorber, and the molar absorption coefficient of the (E) component with respect to light having a wavelength of 365 nm is in the range of 500 to 50,000 L / (mol·cm). The photosensitive resin composition of the present embodiment contains the above components (A) to (E) as essential components, and thus has excellent resolution and adhesion, and can form a fine resist pattern. The photosensitive resin composition may further contain a hydrogen donor or other components as necessary. Hereinafter, each component used in the photosensitive resin composition of the present embodiment will be described in more detail.

[0019] (Component (A): Binder polymer) The photosensitive resin composition of the present embodiment can have improved resolution and adhesion by using a binder polymer that includes a structural unit derived from a (meth)acrylate compound having a dicyclopentanyl group.

[0020] The component (A) can be produced, for example, by radical polymerization of a polymerizable monomer containing a (meth)acrylate compound having a dicyclopentanyl group. In order to improve the hydrophobicity of the binder polymer, for example, a compound represented by the following formula (1) may be used as the (meth)acrylate compound having a dicyclopentanyl group. [ka]

[0021] In formula (1), Y represents a hydrogen atom or a methyl group, R represents an alkylene group having 1 to 4 carbon atoms, X represents a dicyclopentanyl group, and n represents an integer of 0 to 2.

[0022] Examples of the (meth)acrylate compound having a dicyclopentanyl group include dicyclopentanyl (meth)acrylate, dicyclopentanyloxyethyl (meth)acrylate, dicyclopentanyloxypropyl (meth)acrylate, and dicyclopentanyloxypropyloxyethyl (meth)acrylate. From the viewpoint of further increasing the hydrophobicity of the binder polymer, dicyclopentanyl (meth)acrylate may be used.

[0023] From the viewpoint of further improving the resolution and adhesion of the photosensitive resin composition, the content of the structural unit derived from a (meth)acrylate compound having a dicyclopentanyl group (hereinafter also referred to as a "dicyclopentanyl-based structural unit") may be 1 to 50 mass%, 2 to 40 mass%, 3 to 30 mass%, or 3 to 25 mass%, preferably 4 to 20 mass%, more preferably 5 to 15 mass%, and even more preferably 6 to 10 mass%, based on the total mass (100 mass%) of the structural units derived from the polymerizable monomers constituting the binder polymer.

[0024] The component (A) may further contain a structural unit derived from (meth)acrylic acid from the viewpoint of improving alkaline developability, and may further contain a structural unit derived from styrene or a styrene derivative (hereinafter also referred to as a "styrene-based structural unit") from the viewpoint of improving resolution and adhesion and reducing the amount of resist tail generation.

[0025] From the viewpoint of improving the hydrophobicity of the binder polymer, a compound represented by the following formula (2) may be used as the styrene or styrene derivative. [ka]

[0026] In formula (2), R 11 represents a hydrogen atom or a methyl group, R 12 each independently represents a hydrogen atom, an alkyl group, a (meth)acryloyl group, a phenyl group or a derivative thereof; and n represents an integer of 1 to 5.

[0027] Styrene derivatives include, for example, vinyltoluene, α-methylstyrene, p-methylstyrene, and p-ethylstyrene.

[0028] From the viewpoint of improving resolution and adhesion and reducing the amount of resist tail generation, the content of the dicyclopentanyl structural unit and the styrene structural unit may be 50 mass% or more, 55 mass% or more, or 58 mass% or more based on the total mass of the structural units derived from the polymerizable monomers constituting the binder polymer. From the viewpoint of appropriately shortening the development time and reducing the occurrence of undeveloped portions, the content of the dicyclopentanyl structural unit and the styrene structural unit may be 85 mass% or less, 80 mass% or less, or 75 mass% or less.

[0029] From the viewpoint of improving the resolution, adhesion, and suppression of the occurrence of resist tailing, the content of the structural unit derived from (meth)acrylic acid may be 10 to 40 mass%, 15 to 35 mass%, or 20 to 30 mass%, based on the total mass of the structural units derived from the polymerizable monomers constituting the binder polymer.

[0030] The component (A) may further contain a structural unit derived from a polymerizable monomer other than the above (hereinafter also referred to as "other monomer"). Examples of the other monomer include benzyl (meth)acrylate or a derivative thereof, cycloalkyl (meth)acrylate, furfuryl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, isobornyl (meth)acrylate, adamantyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, glycidyl (meth)acrylate, 2,2,2-trifluoroethyl (meth)acrylate, 2,2,3,3-tetrafluoropropyl (meth)acrylate, β-furyl (meth)acrylic acid, β-styryl (meth)acrylic acid, maleic acid, maleic anhydride, maleic acid monoalkyl ester, fumaric acid, cinnamic acid, α-cyanocinnamic acid, itaconic acid, crotonic acid, and propiolic acid. These may be used alone or in combination of two or more.

[0031] The weight average molecular weight (Mw) of the (A) component may be 8000 to 60000, 10000 to 50000, 15000 to 40000, 20000 to 35000, or 25000 to 30000. When Mw is 60000 or less, the resolution and developability tend to improve, and when Mw is 8000 or more, the flexibility of the cured film improves, and chipping and peeling of the resist pattern tend to be less likely to occur. The dispersity (Mw / Mn) of the (A) component may be 1.0 to 3.0, 1.2 to 2.5, 1.4 to 2.3, or 1.5 to 2.0. When the dispersity is smaller, the resolution tends to improve. The weight average molecular weight of the binder polymer is measured by gel permeation chromatography (GPC) (converted by a calibration curve using standard polystyrene).

[0032] The acid value of component (A) may be 100 to 250 mgKOH / g, 120 to 240 mgKOH / g, 140 to 230 mgKOH / g, or 150 to 230 mgKOH / g. When the acid value of component (A) is 100 mgKOH / g or more, it is possible to sufficiently prevent the development time from becoming long, and when it is 250 mgKOH / g or less, it is easy to improve the developer resistance (adhesion) of the cured product of the photosensitive resin composition.

[0033] The acid value of component (A) can be measured as follows. First, 1 g of the binder polymer to be measured for acid value is precisely weighed out. 30 g of acetone is added to the precisely weighed binder polymer and dissolved uniformly. Next, an appropriate amount of phenolphthalein as an indicator is added to the solution, and titration is performed using a 0.1 N aqueous potassium hydroxide (KOH) solution. The acid value is obtained by calculating the number of mg of KOH required to neutralize the acetone solution of the binder polymer to be measured. When the solution to be measured is a mixture of the binder polymer with a synthesis solvent, dilution solvent, etc., the acid value is calculated using the following formula. Acid value = 0.1 x Vf x 56.1 / (Wp x I / 100) In the formula, Vf represents the titration amount (mL) of the KOH aqueous solution, Wp represents the mass (g) of the measured solution containing the binder polymer, and I represents the proportion (mass%) of the non-volatile content in the measured solution containing the binder polymer. In addition, when the binder polymer is mixed with a volatile matter such as a synthesis solvent or a dilution solvent and then blended, the acid value can be measured after removing the volatile matter by heating the mixture at a temperature 10°C or more higher than the boiling point of the volatile matter for 1 to 4 hours before weighing.

[0034] In the photosensitive resin composition of the present embodiment, the component (A) may be one type of binder polymer used alone, or two or more types of binder polymers may be used in any combination. Examples of the binder polymers used in combination of two or more types include two or more types of binder polymers made of different copolymerization components (containing different monomer units as copolymerization components), two or more types of binder polymers with different Mw, and two or more types of binder polymers with different dispersities.

[0035] The content of the component (A) in the photosensitive resin composition of this embodiment may be 20 to 90 mass%, 30 to 80 mass%, or 40 to 65 mass% based on the total solid content of the photosensitive resin composition. When the content of the component (A) is 20 mass% or more, the film tends to have excellent formability, and when it is 90 mass% or less, the sensitivity and resolution tend to be excellent.

[0036] ((B) component: photopolymerizable compound) The (B) component is not particularly limited as long as it has at least one ethylenically unsaturated bond and is a photopolymerizable compound. From the viewpoint of improving the alkali developability, resolution, and peeling properties after curing, the (B) component preferably contains at least one bisphenol type (meth)acrylate, and among the bisphenol type (meth)acrylates, it is more preferable to contain bisphenol A type (meth)acrylate. Examples of the bisphenol A type (meth)acrylate include 2,2-bis(4-((meth)acryloxypolyethoxy)phenyl)propane, 2,2-bis(4-((meth)acryloxypolypropoxy)phenyl)propane, 2,2-bis(4-((meth)acryloxypolybutoxy)phenyl)propane, and 2,2-bis(4-((meth)acryloxypolyethoxypolypropoxy)phenyl)propane. Among these, from the viewpoint of further improving the resolution and peeling properties, 2,2-bis(4-((meth)acryloxypolyethoxy)phenyl)propane is preferred.

[0037] Commercially available bisphenol A type (meth)acrylates include, for example, BPE-200 (trade name, manufactured by Shin-Nakamura Chemical Co., Ltd.) as 2,2-bis(4-((meth)acryloxydipropoxy)phenyl)propane, and BPE-500 (trade name, manufactured by Shin-Nakamura Chemical Co., Ltd.) and FA-321M (trade name, manufactured by Showa Denko Materials Co., Ltd. (formerly Hitachi Chemical Co., Ltd.)). The refractive index of BPE-200 is 1.512, and the refractive index of BPE-500 is 1.532. These bisphenol A type (meth)acrylates may be used alone or in combination of two or more.

[0038] The content of the bisphenol type (meth)acrylate may be 40 to 98% by mass, 50 to 97% by mass, 60 to 95% by mass, or 70 to 90% by mass based on the total amount of the (B) component. If the content is 40% by mass or more, the resolution, adhesion, and suppression of the occurrence of resist tailing will be improved, and if it is 98% by mass or less, the development time will be appropriately shortened and the occurrence of development residue will be more unlikely.

[0039] As the (B) component other than the bisphenol type (meth)acrylate, from the viewpoint of improving the flexibility of the cured product (cured film), at least one of polyalkylene glycol di(meth)acrylate having at least one of a (poly)oxyethylene chain and a (poly)oxypropylene chain in the molecule may be further included, and polyalkylene glycol di(meth)acrylate having both a (poly)oxyethylene chain and a (poly)oxypropylene chain in the molecule may be further included. Examples of the polyalkylene glycol di(meth)acrylate include FA-023M (manufactured by Showa Denko Materials Co., Ltd., trade name), FA-024M (manufactured by Showa Denko Materials Co., Ltd., trade name), and NK Ester HEMA-9P (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name). These may be used alone or in combination of two or more.

[0040] The content of the polyalkylene glycol di(meth)acrylate may be 2 to 40 mass %, 3 to 30 mass %, or 5 to 20 mass % based on the total amount of the component (B).

[0041] Other (B) components may include nonylphenoxy polyethyleneoxy acrylate, phthalic acid compounds, (meth)acrylic acid polyol esters, (meth)acrylic acid alkyl esters, etc. Among them, from the viewpoint of improving the resolution, adhesion, resist shape, and peeling properties after curing in a well-balanced manner, the (B) component may contain at least one selected from nonylphenoxy polyethyleneoxy acrylate and phthalic acid compounds. However, since the refractive index of these compounds is relatively low, from the viewpoint of improving the resolution, the content thereof may be 5 to 50 mass%, 5 to 40 mass%, or 10 to 30 mass% based on the total amount of the (B) component.

[0042] Examples of nonylphenoxy polyethyleneoxyacrylates include nonylphenoxy triethyleneoxyacrylate, nonylphenoxy tetraethyleneoxyacrylate, nonylphenoxy pentaethyleneoxyacrylate, nonylphenoxy hexaethyleneoxyacrylate, nonylphenoxy heptaethyleneoxyacrylate, nonylphenoxy octaethyleneoxyacrylate, nonylphenoxy nonaethyleneoxyacrylate, nonylphenoxy decaethyleneoxyacrylate, and nonylphenoxy undecaethyleneoxyacrylate.

[0043] Examples of the phthalic acid compound include γ-chloro-β-hydroxypropyl-β'-(meth)acryloyloxyethyl-o-phthalate, β-hydroxyethyl-β'-(meth)acryloyloxyethyl-o-phthalate, and β-hydroxypropyl-β'-(meth)acryloyloxyethyl-o-phthalate, and among them, γ-chloro-β-hydroxypropyl-β'-(meth)acryloyloxyethyl-o-phthalate may be used. γ-Chloro-β-hydroxypropyl-β'-methacryloyloxyethyl-o-phthalate is commercially available as FA-MECH (trade name, manufactured by Showa Denko Materials Co., Ltd.).

[0044] From the viewpoint of improving sensitivity and reducing tailing, the component (B) may contain a (meth)acrylic acid polyol ester. Examples of the (meth)acrylic acid polyol ester include trimethylolpropane polyethoxy tri(meth)acrylate, trimethylolpropane polypropoxy tri(meth)acrylate, trimethylolpropane polybutoxy tri(meth)acrylate, trimethylolpropane polyethoxy polypropoxy tri(meth)acrylate, trimethylolethane polyethoxy tri(meth)acrylate, trimethylolethane polypropoxy tri(meth)acrylate, trimethylolethane polybut ... Examples of the polyethoxypolypropoxytri(meth)acrylate include pentaerythritol polyethoxytri(meth)acrylate, pentaerythritol polypropoxytri(meth)acrylate, pentaerythritol polybutoxytri(meth)acrylate, pentaerythritol polyethoxypolypropoxytri(meth)acrylate, glyceryl polyethoxytri(meth)acrylate, glyceryl polypropoxytri(meth)acrylate, glyceryl polybutoxytri(meth)acrylate, and glyceryl polyethoxypolypropoxytri(meth)acrylate.

[0045] The content of component (B) is preferably 20 to 60 parts by mass, more preferably 30 to 55 parts by mass, and even more preferably 35 to 50 parts by mass, relative to 100 parts by mass of the total amount of components (A) and (B). When the content of component (B) is within this range, the photosensitive resin composition exhibits better photosensitivity and coating properties in addition to better resolution, adhesion, and resist tail generation properties.

[0046] (Component (C): Photopolymerization initiator) The component (C) is not particularly limited, but in order to improve the sensitivity and resolution in a well-balanced manner, a hexaarylbiimidazole derivative or an acridine compound having one or more acridinyl groups may be used. In particular, when the photosensitive layer is exposed to an actinic ray of 390 nm to 420 nm, in terms of sensitivity and adhesion, the component (C) may contain an acridine compound having one or more acridinyl groups.

[0047] Examples of the 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, Examples of the imidazole include 2'-bis-(2-fluorophenyl)-4,4',5,5'-tetrakis-(3-methoxyphenyl)-biimidazole, 2,2'-bis-(2,3-difluoromethylphenyl)-4,4',5,5'-tetrakis-(3-methoxyphenyl)-biimidazole, 2,2'-bis-(2,4-difluorophenyl)-4,4',5,5'-tetrakis-(3-methoxyphenyl)-biimidazole, and 2,2'-bis-(2,5-difluorophenyl)-4,4',5,5'-tetrakis-(3-methoxyphenyl)-biimidazole. Among them, from the viewpoint of sensitivity and resolution, 2-(o-chlorophenyl)-4,5-diphenylimidazole dimer is preferred. As the 2-(o-chlorophenyl)-4,5-diphenylimidazole dimer, 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenyl-1,2-biimidazole is commercially available under the trade name "B-CIM" manufactured by Hodogaya Chemical Co., Ltd.

[0048] Examples of the acridine compound include acridine compounds having one acridinyl group, such as 9-phenylacridine, 9-(p-methylphenyl)acridine, 9-(m-methylphenyl)acridine, 9-(p-chlorophenyl)acridine, 9-(m-chlorophenyl)acridine, 9-aminoacridine, 9-dimethylaminoacridine, 9-diethylaminoacridine, and 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)ethane, 1,4-bis(9-acridinyl)butane, 1,6-bis(9-acridinyl)hexane, and 1,8-bis(9-acridinyl)hexane. Examples of acridine compounds having two acridinyl groups include 1,10-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. These compounds may be used alone or in combination of two or more.

[0049] Other examples of the photopolymerization initiator include benzophenones such as 4,4'-bis(diethylamino)benzophenone; aromatic ketones such as 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1,2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-propanone-1; quinones such as alkylanthraquinone; benzoin ether compounds such as benzoin alkyl ether; benzoin compounds such as benzoin and alkylbenzoin; benzil derivatives such as benzil dimethyl ketal, N-phenyl Examples of the photopolymerization initiator include glycine, N-phenylglycine derivatives, acylphosphine oxide photopolymerization initiators such as 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide and bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, and oxime ester compounds such as 1,2-octanedione, 1-[4-(phenylthio)phenyl-, 2-(O-benzoyloxime)], ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, 1-(O-acetyloxime). These may be used in combination with hexaarylbiimidazole derivatives or acridine compounds.

[0050] The content of component (C) may be 0.5 to 10 parts by mass, 1 to 8 parts by mass, or 1.5 to 5 parts by mass, based on 100 parts by mass of the total amount of components (A) and (B). When the content of component (C) is within this range, it becomes easy to improve both photosensitivity and resolution in a well-balanced manner.

[0051] (Component (D): Sensitizer) The photosensitive resin composition of the present embodiment contains a sensitizer having an absorption at 340 to 430 nm as the component (D), thereby improving the photosensitivity of the photosensitive resin composition. Examples of the sensitizer include a dialkylaminobenzophenone compound, a pyrazoline compound, an anthracene compound, a coumarin compound, a xanthone compound, a stilbene compound, and a triarylamine compound. From the viewpoint of sensitivity and adhesion, the sensitizer may contain at least one selected from the group consisting of a pyrazoline compound, an anthracene compound, a coumarin compound, and a triarylamine compound, and may contain at least one selected from the group consisting of a pyrazoline compound, an anthracene compound, and a coumarin compound.

[0052] Examples of pyrazoline compounds include 1-phenyl-3-(4-methoxystyryl)-5-(4-methoxyphenyl)pyrazoline, 1-phenyl-3-(4-tert-butylstyryl)-5-(4-tert-butylphenyl)pyrazoline, and 1-phenyl-3-biphenyl-5-(4-tert-butylphenyl)pyrazoline. Examples of anthracene compounds include 9,10-dibutoxyanthracene and 9,10-diphenylanthracene. Examples of coumarin compounds include 3-benzoyl-7-diethylaminocoumarin, 7-diethylamino-4-methylcoumarin, 3,3'-carbonylbis(7-diethylaminocoumarin), and 2,3,6,7-tetrahydro-9-methyl-1H,5H,11H-[1]benzopyrano[6,7,8-ij]kyrolidin-11-one.

[0053] The content of the (D) component may be 0.005 to 1 mass%, 0.008 to 0.8 mass%, or 0.01 to 0.5 mass% based on the total solid content of the photosensitive resin composition. When the content of the (D) component is 0.01 mass% or more, the sensitivity and resolution are further improved, and when the content is 10 mass% or less, the resist shape is prevented from becoming an inverted trapezoid, and the adhesion is further improved. From the viewpoint of the balance between the resolution and the adhesion, the content of the (D) component may be 0.005 to 0.5 mass parts, 0.008 to 0.2 mass parts, or 0.01 to 0.1 mass parts relative to 100 mass parts of the total amount of the (A) component and the (B) component.

[0054] (Component (E): UV absorber) The photosensitive resin composition of the present embodiment contains an ultraviolet absorber as the component (E), and thus can form a fine resist pattern with excellent resolution. A photosensitive layer having a thickness of 10 μm or less has low absorbance at the exposure wavelength and is easily affected by halation on the substrate surface. When a resist pattern with a line width / space width of 5 / 5 μm or less is exposed to light, the reaction proceeds even in the unexposed area due to the halated light, and the solubility of the unexposed area in the developer is likely to decrease. As a method for increasing the absorbance of the photosensitive layer at the exposure wavelength, it is considered to increase the content of the component (D), but since the amount of radicals generated at the initial stage of the reaction during exposure increases, the degree of polymerization of the component (B) decreases, and the adhesion of the exposed area is likely to decrease. In contrast, a photosensitive layer formed from a photosensitive resin composition containing the component (E) increases the absorbance at the exposure wavelength and suppresses halation on the substrate surface, which results in a significant difference in solubility between the exposed area and the unexposed area, thereby enabling high resolution to be achieved and improving the adhesion of the photocured area.

[0055] The component (E) may be a compound that absorbs light in the range of 340 to 430 nm, and may be a compound that efficiently absorbs light with a wavelength of 365 nm. The molar absorption coefficient of the component (E) for light with a wavelength of 365 nm is in the range of 500 to 50,000 L / (mol cm). The molar absorption coefficient is an index of the ease of light absorption. The molar absorption coefficient of the ultraviolet absorber can be measured, for example, by the following procedure.

[0056] First, acetonitrile solutions of ultraviolet absorbers having four or more different concentrations (mol / L) are prepared at room temperature (25°C, the same applies below) using a volumetric flask and a volumetric pipette. Methanol may be used as a diluting solvent if necessary. The concentration (mol / L) can be calculated by dividing the mass (g) of the ultraviolet absorber placed in the volumetric flask by the molecular weight (g / mol) of the ultraviolet absorber, and then dividing it by the volume (L) of the volumetric flask. The molecular weight (g / mol) of the ultraviolet absorber can be measured by mass spectrometry or the like. The prepared acetonitrile solution of the ultraviolet absorber is filled into a quartz cell with an optical path length of 1 cm, and the absorption spectrum of the ultraviolet absorber is measured using a UV-visible spectrophotometer (e.g., Hitachi High-Technologies Corporation, product name: Hitachi Spectrophotometer U-3310). The spectrophotometer is used after stabilizing the light source, and then a background measurement is performed using a quartz cell with a length of 1 cm filled with acetonitrile, and then used to measure the absorption spectrum of the ultraviolet absorber. The measurement conditions are as follows: temperature at the time of solution preparation, slit width 2 nm, scan speed 300 nm / min, sampling interval 0.50 nm, measurement range 600 nm to 300 nm. Confirm that the absorbance at a wavelength of 365 nm does not exceed 2.0 in each measurement. The vertical axis is the absorbance of the UV absorber at a wavelength of 365 nm, and the horizontal axis is the product of the concentration of the UV absorber and the optical path length, and an approximate line is drawn using the least squares method. Confirm that the coefficient of determination is 0.999 or higher. Using the Beer-Lambert law, the slope of the obtained line is calculated as the molar extinction coefficient at a wavelength of 365 nm (L / (mol cm)). Note that in the above method, when the sample concentration is 1×10 -4 If the absorbance at 365 nm measured in mol / L is 0.01 or less, the molar extinction coefficient is defined as 100 or less.

[0057] From the viewpoint of efficiently absorbing light of the exposure wavelength, the molar absorption coefficient of the component (E) for light of 365 nm is 500 to 50,000 L / (mol cm), and may be 800 to 30,000 L / (mol cm), 1,000 to 20,000 L / (mol cm), or 1,100 to 15,000 L / (mol cm).

[0058] When the photosensitive layer is exposed to actinic rays of 340 to 430 nm, the component (E) may contain at least one selected from the group consisting of benzophenone compounds, benzotriazole compounds, and triazine compounds, since it effectively absorbs light of the exposure wavelength, and may contain a benzophenone compound. The benzophenone compound may be a benzophenone compound in which some of the hydrogen atoms are substituted with a group having an oxygen atom, or a benzophenone compound having a hydroxyl group.

[0059] Examples of benzophenone compounds include 4,4'-dimethoxybenzophenone, 4,4'-bis(trimethylacetoxy)benzophenone, 2,4,4'-trihydroxybenzophenone, 2,2',4,4'-tetrahydroxybenzophenone, 2,3,4,4'-tetrahydroxybenzophenone, 2,2',3,4,4'-pentahydroxybenzophenone, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2-hydroxy-4-(octyloxy)benzophenone, and 2-hydroxy-4-methoxy-benzophenone-5-sulfonic acid. Examples of the benzotriazole compound include 2,2-methylenebis[6-(2H-benzotriazol-2-yl)-4-tert-octylphenol], 2-(2'-hydroxy-5'-methacryloxyethylphenyl)-2H-benzotriazole, 2-(2H-benzotriazol-2-yl)-4,6-di-tert-pentylphenol, and 2-(5-chloro-2H-benzotriazol-2-yl)-6-tert-butyl-4-methylphenol. Examples of the triazine compound include 2-[4,6-di(2,4-xylyl)-1,3,5-triazin-2-yl]-5-octyloxyphenol, and 2,4,6-tris(2-hydroxy-4-hexyloxy-3-methylphenyl)-1,3,5-triazine.

[0060] The content of the component (E) may be 0.05 to 5.0 parts by mass, 0.1 to 4.0 parts by mass, or 0.2 to 2.0 parts by mass, based on 100 parts by mass of the total amount of the components (A) and (B). When the content of the component (E) is within this range, it is easy to improve the resolution and adhesion in a well-balanced manner.

[0061] From the viewpoint of further improving the resolution and adhesion of the photosensitive resin composition, the ratio of the absorbance at the exposure wavelength derived from the component (E) may be 30 to 90%, 40 to 90%, or 45 to 85% based on the absorbance at the exposure wavelength of the photosensitive layer. When the ratio of the absorbance attributable to the component (E) is 30% or more, it becomes easier to suppress the influence of halation on the substrate surface, and when it is 90% or less, it becomes easier to further improve the adhesion of the resist pattern to the substrate.

[0062] (Hydrogen donor) The photosensitive resin composition of the present embodiment may further contain a hydrogen donor. This further improves the sensitivity of the photosensitive resin composition. Examples of hydrogen donors include bis[4-(dimethylamino)phenyl]methane, bis[4-(diethylamino)phenyl]methane, N-phenylglycine, and leuco crystal violet. These may be used alone or in combination of two or more.

[0063] When the photosensitive resin composition contains a hydrogen donor, the content thereof may be 0.01 to 10 mass%, 0.05 to 5 mass%, or 0.1 to 2 mass% based on the total solid content of the photosensitive resin composition. When the hydrogen donor content is 0.01 mass% or more, the sensitivity can be further improved, and when it is 10 mass% or less, the excessive hydrogen donor is prevented from precipitating as a foreign matter after film formation.

[0064] (Other Ingredients) The photosensitive resin composition may further contain other components as necessary. Examples of the other components include a photopolymerizable compound (such as an oxetane compound) having at least one cationic polymerizable cyclic ether group in the molecule, a cationic polymerization initiator, a dye (such as malachite green), tribromophenyl sulfone, a photocoloring agent, a thermal coloring inhibitor, a plasticizer (such as p-toluenesulfonamide), a polymerization inhibitor (such as tert-butylcatechol), a silane coupling agent, a pigment, a filler, a defoaming agent, a flame retardant, a stabilizer, an adhesion imparting agent, a leveling agent, a peeling promoter, an antioxidant, a fragrance, an imaging agent, and a thermal crosslinking agent. These are used alone or in combination of two or more. The content of each of the other components may be about 0.01 to 20% by mass.

[0065] The photosensitive resin composition may contain at least one organic solvent in order to improve the handling property of the photosensitive resin composition and adjust the viscosity and storage stability. As the organic solvent, any organic solvent that is commonly used may be used without any particular limitation. Examples of the organic solvent include methanol, ethanol, acetone, methyl ethyl ketone, methyl cellosolve, ethyl cellosolve, toluene, N,N-dimethylformamide, propylene glycol monomethyl ether, and mixed solvents thereof. For example, the (A) component, the (B) component, and the (C) component may be dissolved in an organic solvent to form a solution having a solid content of about 30 to 60 mass% (hereinafter referred to as a "coating liquid"). The solid content means the remaining components obtained by removing volatile components from the solution of the photosensitive resin composition.

[0066] [Photosensitive element] The photosensitive element of the present embodiment includes a support and a photosensitive layer containing the above-mentioned photosensitive resin composition formed on the support. When using the photosensitive element of the present embodiment, the photosensitive layer may be laminated on a substrate and then exposed to light without peeling off the support.

[0067] (Support) The support may be a polymer film (support film) having heat resistance and solvent resistance, such as polyesters such as polyethylene terephthalate (PET), polyolefins such as polypropylene and polyethylene, etc. Among them, the support may be a PET film, which is easily available and has excellent handleability (particularly heat resistance, heat shrinkage rate, and breaking strength) in the manufacturing process.

[0068] The haze of the support may be 0.01 to 1.0%, or 0.01 to 0.5%. When the haze of the support is 0.01% or more, the support itself tends to be easily manufactured, and when it is 1.0% or less, micro defects that may occur in the resist pattern tend to be reduced. Here, "haze" means cloudiness. The haze in the present disclosure refers to a value measured using a commercially available haze meter (turbidity meter) in accordance with the method specified in JIS K 7105. The haze can be measured, for example, using a commercially available turbidity meter such as NDH-5000 (manufactured by Nippon Denshoku Industries Co., Ltd.).

[0069] The number of particles with a diameter of 5 μm or more contained in the support is 5 / mm 2 The support may be a support containing particles. This improves the slipperiness of the support surface, and can improve the resolution and adhesion by well-balanced suppression of light scattering during exposure. The average particle size of the particles may be 5 μm or less, 1 μm or less, or 0.1 μm or less. The lower limit of the average particle size is not particularly limited, but may be 0.001 μm or more.

[0070] Commercially available examples of such supports include three-layer biaxially oriented PET films containing particles in the outermost layer, such as "QS48" (Toray Industries, Inc.), "FB40" (Toray Industries, Inc.), "QS69" (Toray Industries, Inc.), "R705G" (Mitsubishi Chemical Corporation), and "HTF-01" (Teijin Film Solutions Limited), as well as a two-layer biaxially oriented PET film "A-1517" (Toyobo Co., Ltd.), which has a particle-containing layer on one side.

[0071] The thickness of the support may be 1 to 100 μm, 5 to 50 μm, or 5 to 30 μm. When the thickness is 1 μm or more, the support can be prevented from being broken when peeled off, and when the thickness is 100 μm or less, the resolution can be prevented from decreasing.

[0072] (Middle class) The photosensitive element may further include an intermediate layer between the support and the photosensitive layer. The intermediate layer may be a layer containing a water-soluble resin. Examples of the water-soluble resin include a resin containing polyvinyl alcohol as a main component.

[0073] (protective layer) The photosensitive element may further include a protective layer as necessary. As the protective layer, a film in which the adhesive strength between the photosensitive layer and the protective layer is smaller than the adhesive strength between the photosensitive layer and the support may be used, or a film with low fisheyes may be used. Specifically, the protective film may be, for example, a polymer film that can be used as the support described above. From the viewpoint of peelability from the photosensitive layer, the protective film may be a polyethylene film. The thickness of the protective layer may be about 1 to 100 μm, depending on the application.

[0074] [Method of manufacturing photosensitive element] The photosensitive element can be produced, for example, as follows. It can be produced by a production method including preparing the above-mentioned coating liquid, applying the coating liquid onto a support to form a coating layer, and drying the coating layer to form a photosensitive layer. The coating liquid can be applied onto the support by a known method such as roll coating, comma coating, gravure coating, air knife coating, die coating, bar coating, etc.

[0075] The drying of the coating layer is not particularly limited as long as at least a part of the organic solvent can be removed from the coating layer. For example, the drying may be performed at 70 to 150° C. for about 5 to 30 minutes. After drying, the amount of the organic solvent remaining in the photosensitive layer may be 2% by mass or less from the viewpoint of preventing the diffusion of the organic solvent in the subsequent steps.

[0076] The thickness of the photosensitive layer in the photosensitive element can be appropriately selected depending on the application, and may be 1 to 100 μm, 1 to 50 μm, 1 to 40 μm, or 3 to 20 μm after drying. When the thickness of the photosensitive layer is 1 μm or more, industrial coating becomes easy and productivity improves, and when the thickness is 100 μm or less, adhesion and resolution are further improved.

[0077] The photosensitive element can be suitably used, for example, in the method for forming a resist pattern described below. In particular, from the viewpoint of resolution, it is suitable for application to a manufacturing method for forming a conductor pattern by plating treatment.

[0078] [Method of forming resist pattern] The method for forming a resist pattern of this embodiment includes a photosensitive layer forming step of laminating a photosensitive layer containing the photosensitive resin composition or a photosensitive layer of the photosensitive element on a substrate, an exposure step of irradiating a predetermined portion of the photosensitive layer with active light to form a photocured portion, and a development step of removing an area of ​​the photosensitive layer other than the predetermined portion from the substrate. The method for forming a resist pattern may include other steps as necessary. The resist pattern may be a photocured product pattern of the photosensitive resin composition or a relief pattern. The method for forming a resist pattern may also be a method for producing a substrate with a resist pattern.

[0079] (Photosensitive layer formation process) The method of forming the photosensitive layer on the substrate may be, for example, coating and drying a photosensitive resin composition, or removing a protective layer from a photosensitive element, and then heating and pressing the photosensitive layer of the photosensitive element onto the substrate. When a photosensitive element is used, a laminate consisting of a substrate, a photosensitive layer, and a support, which are laminated in order, is obtained. The substrate is not particularly limited, but typically includes a circuit-forming substrate having an insulating layer and a conductor layer formed on the insulating layer, a metal substrate for manufacturing a metal mask, or a die pad (substrate for lead frame) such as an alloy substrate.

[0080] From the viewpoint of further improving the resolution, the surface roughness (Ra) of the substrate may be 10 to 200 nm, 30 to 100 nm, or 40 to 100 nm. By setting Ra to 40 to 100 nm, halation caused by unevenness on the substrate surface can be suppressed, and the resolution is further improved.

[0081] When a photosensitive element is used, it is preferable to carry out the bonding under reduced pressure from the viewpoint of adhesion and followability. The photosensitive layer and / or the substrate may be heated at a temperature of 70 to 130° C. The bonding is carried out under a pressure of about 0.1 to 1.0 MPa (1 to 10 kgf / cm 2 The pressure may be about 100 MPa (about 100 MPa), but these conditions are appropriately selected according to need. If the photosensitive layer is heated to 70 to 130° C., it is not necessary to preheat the substrate in advance, but the substrate can be preheated in order to further improve the adhesion and conformability.

[0082] (Exposure process) In the exposure step, at least a part of the photosensitive layer formed on the substrate is irradiated with active light rays, whereby the part irradiated with the active light rays is photocured to form a latent image. In this case, if the support present on the photosensitive layer is transparent to the active light rays, the active light rays can be irradiated through the support, but if the support is light-shielding, the support is removed before the photosensitive layer is irradiated with the active light rays.

[0083] The exposure method includes a method of irradiating an active light beam imagewise through a negative or positive mask pattern called artwork (mask exposure method). Alternatively, a method of irradiating an active light beam imagewise by a projection exposure method may be used.

[0084] As the light source of the actinic ray, a known light source can be used, for example, a carbon arc lamp, a mercury vapor arc lamp, a high pressure mercury lamp, an extra-high pressure mercury lamp, a xenon lamp, a gas laser such as an argon laser, a solid-state laser such as a YAG laser, a semiconductor laser, etc. that effectively emits ultraviolet light and visible light can be used. The wavelength of the actinic ray may be within the range of 340 nm to 430 nm.

[0085] (Developing process) In the development process, at least a part of the photosensitive layer other than the photocured portion is removed from the substrate, thereby forming a resist pattern on the substrate. If a support is present on the photosensitive layer, the support is removed, and then the area other than the photocured portion (which may also be called the unexposed portion) is removed (developed). There are two development methods, wet development and dry development, and wet development is widely used.

[0086] In the case of wet development, a developer corresponding to the photosensitive resin composition is used, and development is performed by a known development method. Examples of the development method include a dip method, a paddle method, a spray method, a brushing method, a slapping method, a scrubbing method, a swinging immersion method, etc., and from the viewpoint of improving the resolution, a high-pressure spray method may be used. Development may be performed by combining two or more of these methods.

[0087] The composition of the developer is appropriately selected depending on the composition of the photosensitive resin composition, and examples thereof include an alkaline aqueous solution and an organic solvent developer.

[0088] From the viewpoint of safety, stability, and good operability, an alkaline aqueous solution may be used as the developer. Examples of the base of the alkaline aqueous solution include alkali hydroxides such as lithium, sodium, or potassium hydroxides; alkali carbonates such as lithium, sodium, potassium, or ammonium carbonates or bicarbonates; alkali metal phosphates such as potassium phosphate and sodium phosphate; alkali metal pyrophosphates such as sodium pyrophosphate and potassium pyrophosphate; borax, sodium metasilicate, tetramethylammonium hydroxide, ethanolamine, ethylenediamine, diethylenetriamine, 2-amino-2-hydroxymethyl-1,3-propanediol, 1,3-diaminopropanol-2, and morpholine.

[0089] The alkaline aqueous solution used for development may be a dilute solution of 0.1 to 5 mass % sodium carbonate, a dilute solution of 0.1 to 5 mass % potassium carbonate, a dilute solution of 0.1 to 5 mass % sodium hydroxide, a dilute solution of 0.1 to 5 mass % sodium tetraborate, etc. The pH of the alkaline aqueous solution used for development may be in the range of 9 to 11, and the temperature can be adjusted according to the alkaline developability of the photosensitive layer.

[0090] The alkaline aqueous solution may contain, for example, a surfactant, an antifoaming agent, a small amount of an organic solvent for promoting development, etc. Examples of the organic solvent used in the alkaline aqueous solution include acetone, ethyl acetate, an 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.

[0091] Examples of organic solvents used in the organic solvent developer include 1,1,1-trichloroethane, N-methylpyrrolidone, N,N-dimethylformamide, cyclohexanone, methyl isobutyl ketone, and γ-butyrolactone. To prevent ignition, water may be added to these organic solvents in an amount of 1 to 20% by mass to prepare the organic solvent developer.

[0092] In the method for forming a resist pattern in this embodiment, after removing the uncured portion in the development step, heating at about 60 to 250° C. or applying 0.2 to 10 J / cm 2 is performed as necessary. 2 The method may further include a step of hardening the resist pattern by exposure to light of about 1000 nm.

[0093] [Printed wiring board manufacturing method] The method for producing a printed wiring board according to the present embodiment includes a step of forming a conductor pattern by plating or etching a substrate on which a resist pattern has been formed by the above-described method for forming a resist pattern. The method for producing a printed wiring board may include other steps, such as a resist pattern removal step, as necessary.

[0094] In the plating process, the conductive layer provided on the substrate is plated using the resist pattern formed on the substrate as a mask. After the plating process, the resist is removed by removing the resist pattern as described below, and the conductive layer covered by the resist may be etched to form a conductive pattern.

[0095] The plating method may be electrolytic plating or electroless plating, or may be electrolytic plating. Examples of electrolytic plating include copper plating, solder plating, nickel plating, and gold plating. In the etching process, a resist pattern formed on a substrate is used as a mask to etch away a conductive layer provided on the substrate, thereby forming a conductive pattern. The method of the etching process is appropriately selected according to the conductive layer to be removed. Examples of the etching solution include a cupric chloride solution, a ferric chloride solution, an alkaline etching solution, and a hydrogen peroxide-based etching solution.

[0096] After the etching or plating process, the resist pattern on the substrate may be removed. The resist pattern can be removed, for example, by stripping with an aqueous solution that is more strongly alkaline than the aqueous solution used in the development process. As the aqueous solution, for example, a 1 to 10% by mass sodium hydroxide aqueous solution, a 1 to 10% by mass potassium hydroxide aqueous solution, etc., can be used.

[0097] When the resist pattern is removed after the plating process, the conductor layer covered with the resist is etched by an etching process to form a conductor pattern, thereby manufacturing a desired printed wiring board. The method of the etching process is appropriately selected depending on the conductor layer to be removed. For example, the above-mentioned etching solution can be used.

[0098] The method for manufacturing a printed wiring board according to this embodiment can be applied to the manufacture of not only single-layer printed wiring boards but also multi-layer printed wiring boards, and can also be applied to the manufacture of printed wiring boards having small diameter through holes. EXAMPLES

[0099] The present disclosure will be specifically described below with reference to examples, but the present disclosure is not limited to these examples. In addition, unless otherwise specified, "parts" and "%" are based on mass.

[0100] (Binder polymer (A-1)) 162g of methacrylic acid, 395g of styrene, 44g of dicyclopentanyl methacrylate, and 6g of azobisisobutyronitrile, which are polymerizable monomers, were mixed to prepare solution a. 11g of 1-methoxy-2-propanol and 17g of toluene (mass ratio 2:3) were mixed to prepare solution b. 0.6g of azobisisobutyronitrile was mixed with a mixture of 11g of 1-methoxy-2-propanol and 17g of toluene (mass ratio 2:3) to prepare solution c.

[0101] A mixture of 323 g of 1-methoxy-2-propanol and 484 g of toluene (mass ratio 2:3) was placed in a flask equipped with a stirrer, a reflux condenser, a thermometer, a dropping funnel, and a nitrogen gas inlet tube. Next, the mixture was stirred while blowing nitrogen gas into the flask, and heated to 80°C.

[0102] The solution a was added dropwise to the mixture in the flask over 4 hours, and then the solution b was added dropwise over 10 minutes. The mixture was then stirred at 80°C for 2 hours. The solution c was then added dropwise to the solution in the flask over 10 minutes, and then stirred at 80°C for 2 hours. The solution in the flask was then heated to 95°C over 30 minutes while continuing to stir. The solution c was then newly added dropwise over 10 minutes, and then stirred at 95°C for 3 hours. The mixture was then stopped to stir, and cooled to room temperature to obtain a solution of binder polymer (A-1). In this specification, room temperature means 25°C.

[0103] The Mw of the binder polymer (A-1) was 27900. The Mw was measured by gel permeation chromatography (GPC) and calculated by converting the standard polystyrene calibration curve. The calibration curve was approximated by a cubic equation of the universal calibration curve according to JIS K 7252-2 (2016) using a set of five standard polystyrene samples (PStQuick MP-H, PStQuick B [product name, manufactured by Tosoh Corporation]). The GPC conditions are shown below.

[0104] (GPC conditions) Columns: Gelpack GL-R440, Gelpack GL-R450 and Gelpack GL-R400M (all manufactured by Showa Denko Materials Co., Ltd.) Eluent: Tetrahydrofuran Measurement temperature: 40℃ Flow rate: 2.05mL / min Concentration: 5mg / mL Injection volume: 200μL Detector: Hitachi L-2490 type RI (manufactured by Hitachi, Ltd.)

[0105] (Binder polymer (A-2)) A solution of binder polymer (A-2) was obtained in the same manner as for obtaining the solution of binder polymer (A-1), except that methacrylic acid, methyl methacrylate, styrene, and benzyl methacrylate were used in the mass ratio shown in Table 1 as the polymerizable monomers.

[0106] Table 1 shows the mass ratio (%) of the polymerizable monomer and Mw of the binder polymers (A-1) and (A-2).

[0107] [Table 1]

[0108] [Examples 1 to 3 and Comparative Example 1] <Preparation of Photosensitive Resin Composition> Photosensitive resin compositions of the examples and comparative examples were prepared by mixing binder polymer (A-1) or (A-2) with (B) photopolymerizable compound, (C) photopolymerization initiator, (D) sensitizer, (E) UV absorber, other components, and solvent in the amounts (parts by mass) shown in Table 2. The amounts of binder polymer shown in Table 2 are the masses of nonvolatile components (solid content).

[0109] ((B) Photopolymerizable compound) B-1: 2,2-bis(4-(methacryloxypentaethoxy)phenyl)propane (manufactured by Showa Denko Materials Co., Ltd., product name: FA-321M) B-2: Ethoxylated bisphenol A dimethacrylate (EO average 4 mol modified) (manufactured by Shin-Nakamura Chemical Co., Ltd., product name: BPE-200) B-3: (PO)(EO)(PO) modified polyethylene glycol dimethacrylate (modified with an average of 6 mol of EO and an average of 12 mol of PO) (manufactured by Showa Denko Materials Co., Ltd., product name: FA-024M) ((C) Photopolymerization initiator) C-1: 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenyl-1,2-biimidazole (manufactured by Hodogaya Chemical Co., Ltd., trade name: B-CIM) ((D) Sensitizer) D-1: 1-phenyl-3-(4-methoxystyryl)-5-(4-methoxyphenyl)pyrazoline (manufactured by Nippon Chemical Industry Co., Ltd., molar absorption coefficient (365 nm): 34,400 L / (mol cm)) ((E) Ultraviolet absorber) E-1: 2,2',4,4'-tetrahydroxybenzophenone (manufactured by Shipro Chemical Co., Ltd., molar absorption coefficient (365 nm): 10878 L / (mol cm)) E-2: 2-Hydroxy-4-(octyloxy)benzophenone (Chemipro Chemicals, molar absorption coefficient (365 nm): 1220 L / (mol cm)) ((F) Other Ingredients) F-1: Leuco Crystal Violet (Yamada Chemical Co., Ltd.) F-2: Malachite Green (Osaka Organic Chemical Industry Co., Ltd.) F-3: tert-Butylcatechol (FUJIFILM Wako Pure Chemical Industries, Ltd.) F-4: Benzotriazole derivative (manufactured by Sanwa Chemical Industries, Ltd., product name: SF-808H, molar absorption coefficient (365 nm): 100 L / (mol cm) or less) F-5: 3-mercaptopropyltrimethoxysilane (Shin-Etsu Chemical Co., Ltd.)

[0110] <Preparation of Photosensitive Element> The solution of the photosensitive resin composition was uniformly applied onto a 16 μm-thick polyethylene terephthalate film (manufactured by Toray Industries, Inc., product name "QS69"), dried for 10 minutes in a hot air convection dryer at 90° C., and then protected with a polyethylene film (manufactured by Tamapoly Co., Ltd., product name "NF-15A") to obtain a laminate (photosensitive element) in which the support, photosensitive layer, and protective film were laminated. The film thickness of the photosensitive layer after drying was 6 μm.

[0111] <Measurement of absorbance> A photosensitive element was laminated (laminated) on the surface of a slide glass (manufactured by Matsunami Glass Industry Co., Ltd., white slide glass cut No. 1 S1126). The lamination was performed by using a heat roll at 110°C with a pressure of 0.2 MPa and a roll speed of 1.0 m / min, with the photosensitive layer of the photosensitive element in contact with the surface of the slide glass while peeling off the protective layer. After the photosensitive layer was laminated on the slide glass, the support was peeled off. The absorbance of the photosensitive layer was measured using a U-3310 spectrophotometer (manufactured by Hitachi High-Tech Science Co., Ltd., measurement conditions: wavelength range: 330 to 700 nm, scan speed: 300 nm / min, scan interval: 0.50 nm). A baseline measurement was performed using untreated slide glass as a reference and sample. From the obtained measurement spectrum, the absorbance (A total The absorbance of Comparative Example 1, which does not contain an ultraviolet absorber, was recorded as the absorbance (A D ) and the absorbance (A E ) to A total From A D The value was calculated by subtracting

[0112] <Preparation of Laminate> A substrate (Ra: 40 nm) having a copper layer was pickled and washed with water, and then dried with an air flow. The substrate was then heated to 80°C, and a photosensitive element was laminated (laminated) onto the copper surface of the substrate. The lamination was performed using a heat roll at 110°C, with a pressure of 0.4 MPa and a roll speed of 1.0 m / min, with the photosensitive layer of the photosensitive element in contact with the copper surface of the substrate while peeling off the protective layer. In this way, a laminate was obtained in which the substrate, photosensitive layer, and support were laminated in this order. The obtained laminate was used as a test piece for the following test.

[0113] <Evaluation of resolution and adhesion> On the support of the test piece, a glass chrome type phototool (resolution negative: one having a wiring pattern with a line width / space width of x / x (x: 1 to 10, unit: μm), adhesion negative: one having a wiring pattern with a line width / space width of x / x (x: 1 to 18, unit: μm)) was used as a negative for evaluating resolution and adhesion, and the photosensitive layer was exposed with a predetermined amount of energy using a projection exposure device (manufactured by Ushio Inc., product name "UX-44101SM") with an ultra-high pressure mercury lamp (365 nm) as a light source. After exposure, the support was peeled off to expose the photosensitive layer, and a 1% by mass aqueous solution of sodium carbonate at 27°C was sprayed for three times the shortest development time (the shortest time for the unexposed part to be removed) to remove the unexposed part (development process).

[0114] After development, the space portion (unexposed portion) was completely removed, and the line portion (exposed portion) was formed without twisting, meandering, or chipping. The smallest line width / space width value among the resist patterns was used to evaluate the resolution and adhesion. At this time, the line width / space width value evaluated at the exposure dose at which the resist line width of the adhesion negative pattern (line width / space width=2 / 2 μm) was about 2.0 μm was recorded as the resolution and adhesion. The smaller this value, the better the resolution and adhesion.

[0115] <Evaluation of resist shape> Among the resist patterns after development, a scanning electron microscope (SEM, SU-8010, Hitachi High-Technologies Corporation), accelerating voltage: 5.0 kV) was used to measure the line widths of the top (x) and bottom (y) of the resist. From the measured values, the taper ratio (x / y) was calculated as an evaluation criterion for the resist shape. The closer the taper ratio is to 1, the closer the resist shape is to a rectangle, and the better it is. The resist shape was evaluated as follows: a taper ratio of 0.9 or more and less than 1.1 is "A", a taper ratio of 1.1 or more and less than 1.3 is "B", and a taper ratio of 1.3 or more is "C".

[0116] [Table 2]

[0117] It can be seen from Table 2 that the photosensitive resin compositions of Examples 1 to 3 are superior in resolution and adhesion to those of Comparative Examples 1 and 2, and are capable of forming fine resist patterns.

Claims

1. The composition comprises a binder polymer including a structural unit derived from a (meth)acrylate compound having a dicyclopentanyl group, a photopolymerizable compound, a photopolymerization initiator, a sensitizer having an absorption in the range of 340 to 430 nm, and an ultraviolet absorber; the photopolymerization initiator contains a hexaarylbiimidazole derivative or an acridine compound having one or more acridinyl groups, the sensitizer comprises at least one selected from the group consisting of a pyrazoline compound, an anthracene compound, and a triarylamine compound; the ultraviolet absorber comprises a benzophenone compound having a hydroxy group, The photosensitive resin composition, wherein the ultraviolet absorber has a molar absorption coefficient of 500 to 50,000 L / (mol cm) for light having a wavelength of 365 nm.

2. 2. The photosensitive resin composition according to claim 1, wherein the content of the ultraviolet absorber is 0.05 to 5.0 parts by mass per 100 parts by mass of the total amount of the binder polymer and the photopolymerizable compound.

3. 3. The photosensitive resin composition according to claim 1, wherein the content of the structural unit derived from the (meth)acrylate compound having a dicyclopentanyl group is 1 to 50 mass% based on the total mass of the structural units derived from the polymerizable monomers constituting the binder polymer.

4. The photosensitive resin composition according to any one of claims 1 to 3, wherein the photopolymerizable compound comprises bisphenol A type (meth)acrylate.

5. 5. The photosensitive resin composition according to claim 4, wherein the bisphenol A type (meth)acrylate comprises 2,2-bis(4-((meth)acryloxypolyethoxy)phenyl)propane.

6. 5. The photosensitive resin composition according to claim 4, wherein the bisphenol A type (meth)acrylate comprises 2,2-bis(4-((meth)acryloxydipropoxy)phenyl)propane.

7. 5. The photosensitive resin composition according to claim 4, wherein the bisphenol A type (meth)acrylate comprises 2,2-bis(4-(methacryloxypentaethoxy)phenyl)propane.

8. The photosensitive resin composition according to any one of claims 1 to 7, wherein the photopolymerizable compound comprises a polyalkylene glycol di(meth)acrylate.

9. The photosensitive resin composition according to any one of claims 1 to 8, wherein the binder polymer further contains a structural unit derived from styrene or a styrene derivative.

10. 10. The photosensitive resin composition according to claim 9, wherein the content of the structural unit derived from the (meth)acrylate compound having a dicyclopentanyl group and the structural unit derived from the styrene or styrene derivative is 50 mass% or more based on the total mass of the structural units derived from polymerizable monomers constituting the binder polymer.

11. A photosensitive element comprising: a support; and a photosensitive layer formed on the support, the photosensitive layer comprising the photosensitive resin composition according to any one of claims 1 to 10.

12. a photosensitive layer forming step of laminating a photosensitive layer containing the photosensitive resin composition according to any one of claims 1 to 10 or the photosensitive layer of the photosensitive element according to claim 11 on a substrate; an exposure step of irradiating a predetermined portion of the photosensitive layer with active light to form a photocured portion; and a developing step of removing the area of ​​the photosensitive layer other than the predetermined portion from the substrate.

13. 13. The method for forming a resist pattern according to claim 12, wherein the wavelength of the actinic light is within the range of 340 nm to 430 nm.

14. A method for producing a printed wiring board, comprising the step of etching or plating a substrate on which a resist pattern has been formed by the method for forming a resist pattern according to claim 12 or 13, to form a conductor pattern.

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