JP5618118B2 - Photosensitive resin composition, and photosensitive element, solder resist and printed wiring board using the same - Google Patents

Description

  The present invention relates to a photosensitive resin composition, and a photosensitive element, a solder resist, and a printed wiring board using the same.

  With the miniaturization, weight reduction, and multi-functionalization of various electric and electronic components, the semiconductor elements, semiconductor packages, printed wiring boards, flexible wiring boards, etc. that form them are becoming more precise and form minute opening patterns. A solder resist that can be used is required.

  As a method for forming a solder resist, for example, a method of screen printing a thermosetting resin on a conductor layer of a printed wiring board is known. However, since there is a limit to the miniaturization of the resist pattern in such a method, it is difficult to cope with the recent high definition of the printed wiring board.

  Therefore, in order to achieve a finer resist pattern, a photoresist method has been used. In this photoresist method, a photosensitive resin composition layer made of a photosensitive resin composition is formed on a substrate, the photosensitive resin composition layer is cured by exposure of a predetermined pattern, and unexposed portions are removed by development. Thus, a cured film having a predetermined pattern is formed.

  The photosensitive resin composition for solder resist generally requires characteristics such as developability, high resolution, insulation, solder heat resistance, and gold plating resistance. In particular, for a solder resist for a semiconductor package substrate on which a semiconductor chip is directly mounted, in addition to the above characteristics, for example, crack resistance against a temperature cycle test (TCT) of −65 to 150 ° C. HAST resistance to ultra-accelerated high temperature and high humidity life test (HAST) is required.

  Further, the solder resist has a fine opening pattern that exposes a part of the conductor layer having the wiring pattern in order to solder and connect the substrates. From the viewpoint of solder adhesion, the opening shape (via shape) of the opening (via hole) is required to be a forward tapered shape. This is because in the soldering process such as IR reflow, if the via shape is a reverse taper shape such as an undercut or an overhang, it is difficult to attach the solder, and in the subsequent process, the solder can be easily removed.

  By the way, as the photosensitive resin composition for the solder resist, a liquid photosensitive resin composition is usually used in the field of printed wiring boards. The liquid solder resist is composed of a two-component type photosensitive resin composition in which a thermosetting epoxy resin and a photosensitive prepolymer containing a carboxylic acid group for imparting alkali developability are separately separated. Things are common. As the photosensitive prepolymer, an alkali developable photosensitive prepolymer which is obtained by adding acrylic acid to a cresol novolak type epoxy resin and then acid-modifying with an acid anhydride or the like is widely used (for example, see Patent Document 1). .

  Since the reaction of the carboxylic acid group of the epoxy resin and the photosensitive prepolymer proceeds at room temperature, the storage stability (pot life) after mixing the two liquids is from a few hours. The usage conditions are limited, such as being short and short and having to be mixed immediately before use. Therefore, a one-component type photosensitive resin composition having a storage stability improved by using a blocked isocyanate compound instead of an epoxy resin as a thermosetting agent is disclosed (for example, see Patent Document 2).

  On the other hand, in recent years, a dry film type solder resist has been strongly desired from the viewpoint of improving film thickness uniformity, surface smoothness, thin film formability, and handleability. According to such a dry film type photosensitive resin composition, in addition to the above characteristics, effects such as simplification of a process for forming a resist and reduction of a solvent discharge amount at the time of forming the resist can be obtained. As a dry film type solder resist having excellent storage stability, a photosensitive film containing a polymer having a carboxyl group, a photopolymerizable compound, a photopolymerization initiator, and a bismaleimide compound is disclosed (for example, Patent Documents). 3).

  Further, it contains a copolymer obtained by reacting 0.1 to 1.2 equivalents of a primary amine compound with respect to the anhydride group of the maleic anhydride copolymer, a polymerizable compound and a photopolymerization initiator. A photosensitive film is disclosed (for example, see Patent Document 4).

JP-A 61-243869 JP 2001-305726 A JP 2004-287267 A JP 2005-316431 A

  However, the conventional photosensitive resin composition described in Patent Document 2 is excellent in alkali developability, storage stability, curability, chemical resistance, and adhesion, but the cured film has heat resistance, HAST resistance, and resistance. There was a problem that the reliability required for a solder resist such as cracking property was insufficient, and it was difficult to obtain a good via shape.

  In addition, the conventional photosensitive resin composition described in Patent Document 3 is excellent in storage stability, film formability, and high temperature and humidity resistance, but has insufficient characteristics that require heat resistance such as a temperature cycle test. Met.

  Furthermore, the conventional photosensitive resin composition described in Patent Document 4 is excellent in storage stability, tackiness of the surface of the photosensitive resin composition layer, sensitivity, resolution, and surface curability, but the cured film The reliability required for solder resists such as heat resistance, HAST resistance and crack resistance was insufficient.

  Thus, it is difficult for the conventional photosensitive resin composition to achieve both alkali developability and storage stability, and reliability such as heat resistance, HAST resistance, and crack resistance of the cured film. It was.

  The present invention has been made in view of the above problems, and is excellent in storage stability as a one-pack type or dry film, has good sensitivity, alkali developability, and via shape, and crack resistance of a cured film, It aims at providing the photosensitive resin composition which is excellent in HAST tolerance, and the photosensitive element, solder resist, and printed wiring board using the same.

The present invention includes [1] (A) a binder polymer, (B) a photopolymerizable compound having an ethylenically unsaturated bond, (C) a photopolymerization initiator, and (D) a thermosetting agent. The (B) component provides a photosensitive resin composition containing (B-1) a photopolymerizable compound having a fluorene skeleton and an oxyethylene group or oxypropylene group in the molecule.
The photosensitive resin composition of the present invention contains a specific compound as the component (B), so that the solder resist has excellent sensitivity, alkali developability, via shape, and excellent crack resistance and HAST resistance. Can be formed.

  Moreover, this invention provides the photosensitive resin composition as described in said [1] whose [2] said (B-1) component is a compound represented by following General formula (1).

［一般式（１）中、Ｒ^１及びＲ^２は、それぞれ独立に水素原子又はメチル基を示し、Ｒ^３及びＲ^４は、それぞれ独立にハロゲン原子、アミノ基、炭素数１〜６のアルキル基、炭素数１〜６のアルコキシ基又は炭素数１〜６のアルキルアミノ基を示し、ｐ及びｒはそれぞれ独立に０〜４の整数を示す。ｐ又はｒが２以上の場合、複数存在するＲ^３又はＲ^４は、それぞれ同一でも異なっていてもよい。−（Ａ−Ｏ）−及び−（Ｏ−Ｂ）−はそれぞれ独立に、（ポリ）オキシエチレン鎖、（ポリ）オキシプロピレン鎖、又はエチレンオキサイドとプロピレンオキサイドとのブロック共重合鎖若しくはランダム共重合鎖を示し、−（Ａ−Ｏ）−及び−（Ｏ−Ｂ）−に含まれるオキシエチレン基又はオキシプロピレン基の繰り返し総数；ｍ＋ｎは１〜２０である。］

[In General Formula (1), R ¹ and R ² each independently represent a hydrogen atom or a methyl group, and R ³ and R ⁴ each independently represent a halogen atom, an amino group, or an alkyl group having 1 to 6 carbon atoms. Represents an alkoxy group having 1 to 6 carbon atoms or an alkylamino group having 1 to 6 carbon atoms, and p and r each independently represent an integer of 0 to 4. When p or r is 2 or more, a plurality of R ³ or R ⁴ may be the same or different. -(A-O)-and-(OB)-are each independently a (poly) oxyethylene chain, a (poly) oxypropylene chain, or a block copolymer chain or random copolymer of ethylene oxide and propylene oxide. Represents a chain, and the total number of repeating oxyethylene groups or oxypropylene groups contained in-(AO)-and-(OB)-; m + n is 1-20. ]

  The photosensitive resin composition of the present invention contains the compound represented by the general formula (1) as the component (B), so that the sensitivity, alkali developability, via shape are good, and crack resistance, A solder resist having excellent HAST resistance can be formed.

  In addition, the present invention provides: [3] The component (B) is a compound obtained by reacting (B-2) a bisphenol A-based (meth) acrylate compound, a polyhydric alcohol with an α, β-unsaturated carboxylic acid, or The photosensitive resin composition according to the above [1] or [2], comprising one or more selected from the group consisting of (meth) acrylate compounds having a urethane bond in the molecule. Thereby, the flexibility at the time of film formation and the crack resistance of a cured film can further be improved.

Moreover, this invention provides the photosensitive resin composition in any one of said [1]-[3] which further contains [4] (E) sensitizer. Thereby, the sensitivity and resolution of the photosensitive resin composition can be further improved.
[5] The above [1], wherein the content of the component (E) is 0.01 to 20% by mass based on the total solid content of the component (A) and the component (B). The photosensitive resin composition in any one of-[4] is provided.

  The present invention also includes [6] a support, and a photosensitive resin composition layer formed on the support, the photosensitive resin composition layer including the photosensitive resin composition according to any one of the above [1] to [5], A photosensitive element is provided. According to the photosensitive element of the present invention, a dry film type solder resist made of the photosensitive resin composition of the present invention can be easily formed.

  Furthermore, the present invention provides [7] a solder resist (“photosensitive” comprising a photocured product of the photosensitive resin composition according to any one of the above [1] to [5] formed on a printed wiring board substrate. Also referred to as “permanent resist”. Since the solder resist according to the present invention is formed from the photosensitive resin composition of the present invention, it has a good via shape and is excellent in crack resistance and HAST resistance.

  The present invention also provides [8] a printed wiring board substrate and a photocured product of the photosensitive resin composition according to any one of the above [1] to [5] formed on the printed wiring board substrate. A printed wiring board provided with a solder resist made of Since the solder resist provided in the printed wiring board of the present invention is formed from the photosensitive resin composition of the present invention, it has a good via shape and is excellent in crack resistance and HAST resistance. .

  According to the present invention, a photosensitive resin composition having excellent storage stability as a one-pack type or dry film, excellent sensitivity, alkali developability and via shape, and excellent crack resistance and HAST resistance of a cured film, and A photosensitive element, a solder resist, and a printed wiring board using the same can be provided.

It is a schematic sectional drawing which shows one Embodiment of the photosensitive element which concerns on this invention. It is a schematic sectional drawing which shows one Embodiment of the opening part of the photosensitive permanent resist which concerns on this invention.

  Hereinafter, preferred embodiments of the present invention will be described. However, the present invention is not limited to the following embodiments. In the present invention, (meth) acrylic acid means acrylic acid or methacrylic acid corresponding thereto, (meth) acrylate means acrylate or corresponding methacrylate, and (meth) acryloyl group means acryloyl group or The corresponding methacryloyl group is meant.

(Photosensitive resin composition)
The photosensitive resin composition of the present invention comprises (A) a binder polymer, (B) a photopolymerizable compound having an ethylenically unsaturated bond, (C) a photopolymerization initiator, and (D) a thermosetting agent. contains.
Hereinafter, the components (A) to (D) will be described in detail.

(A) Binder polymer The component (A) used in the present invention is not particularly limited as long as it is a polymer that can be photocured with a photopolymerizable compound to be described later. For example, acrylic resin, polyurethane, epoxy resin, phenoxy resin And known resins such as polyester, polyamide, polyamide epoxy, polyimide, polyamideimide, polyesterimide, polycarbonate, melamine resin, polyphenylene sulfide, polyoxybenzoyl, polyalkyd, and acid-modified resins thereof. Among them, it is preferable to be obtained by polymerizing a monomer (polymerizable monomer) having an ethylenically unsaturated double bond (such as radical polymerization).

  Examples of such a monomer having an ethylenically unsaturated double bond include acrylamide such as diacetone acrylamide, esters of vinyl alcohol such as acrylonitrile and vinyl-n-butyl ether, and (meth) acrylic acid alkyl esters. , (Meth) acrylic acid tetrahydrofurfuryl ester, (meth) acrylic acid dimethylaminoethyl ester, (meth) acrylic acid diethylaminoethyl ester, (meth) acrylic acid glycidyl ester, 2,2,2-trifluoroethyl (meth) Acrylate, 2,2,3,3-tetrafluoropropyl (meth) acrylate, (meth) acrylic acid, α-bromo (meth) acrylic acid, α-chloro (meth) acrylic acid, β-furyl (meth) acrylic acid , Β-styryl (meth) acrylic acid, etc. ) Acrylic acid monomer, maleic acid, maleic anhydride, maleic acid monomer such as monomethyl maleate, monoethyl maleate, monoisopropyl maleate, fumaric acid, cinnamic acid, α-cyanocinnamic acid, Itaconic acid, crotonic acid, propiolic acid and the like can be mentioned. You may use these individually by 1 type or in combination of 2 or more types arbitrarily.

  As said (meth) acrylic-acid alkylester, the compound etc. which the hydroxyl group, the epoxy group, the halogen atom, etc. substituted by the compound shown by following General formula (2) and the alkyl group of these compounds are mentioned, for example.

［一般式（２）中、Ｒ^５は水素原子又はメチル基を示し、Ｒ^６は炭素数１〜１２のアルキル基を示す。］

[In General Formula (2), R ⁵ represents a hydrogen atom or a methyl group, and R ⁶ represents an alkyl group having 1 to 12 carbon atoms. ]

As the alkyl group having 1 to 12 carbon atoms represented by R ⁶ in the general formula (2), for example, a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, heptyl group, octyl Group, nonyl group, decyl group, undecyl group, dodecyl group and structural isomers thereof.

  Examples of the compound represented by the general formula (2) include (meth) acrylic acid methyl ester, (meth) acrylic acid ethyl ester, (meth) acrylic acid propyl ester, (meth) acrylic acid butyl ester, (meth) Examples include acrylic acid pentyl ester, (meth) acrylic acid hexyl ester, (meth) acrylic acid heptyl ester, (meth) acrylic acid octyl ester, (meth) acrylic acid 2-ethylhexyl ester, and the like. These can be used alone or in any combination of two or more.

  The binder polymer as component (A) is preferably composed of one or more kinds of polymers having a carboxyl group from the viewpoint of alkali developability. Such a (A) binder polymer can be produced, for example, by radical polymerization of a polymerizable monomer having a carboxyl group and another polymerizable monomer.

  The acid value of the binder polymer is, for example, preferably 30 to 150 mgKOH / g, more preferably 50 to 120 mgKOH / g, and 60 to 100 mgKOH / g in the case of a binder polymer such as acrylic or acid-modified polyester. And particularly preferred.

  Moreover, it is preferable that the binder polymer which is (A) component has a structural unit based on (meth) acrylic acid and (meth) acrylic-acid alkylester from a viewpoint of alkali developability and resolution.

  The binder polymer as the component (A) is used singly or in combination of two or more. As a binder polymer in the case of using two or more types in combination, for example, two or more types of binder polymers comprising different copolymerization components, two or more types of binder polymers having different weight average molecular weights, and two or more types of binder polymers having different degrees of dispersion are used. A binder polymer etc. are mentioned. A polymer having a multimode molecular weight distribution described in JP-A No. 11-327137 can also be used.

  The weight average molecular weight (Mw) and number average molecular weight (Mn) of the binder polymer as the component (A) can be measured by gel permeation chromatography (GPC) (converted by a calibration curve using standard polystyrene). . According to this measurement method, the Mw of the binder polymer is preferably 5000 to 150,000, more preferably 10,000 to 120,000, and particularly preferably 30,000 to 100,000. When Mw is less than 5000, the developer resistance tends to decrease, and when it exceeds 150,000, the development time tends to be long.

  The binder polymer as the component (A) preferably has a dispersity (Mw / Mn) of 1.0 to 3.0, and more preferably 1.0 to 2.0. When the degree of dispersion exceeds 3.0, the adhesion and resolution tend to decrease.

  Furthermore, it is preferable that content of (A) component in the photosensitive resin composition of this invention is 10-80 mass% on the basis of the solid content whole quantity of (A) component and (B) component, and 20-20. More preferably, it is 70 mass%, and it is especially preferable that it is 40-60 mass%. If the content is less than 10% by mass, the sensitivity and the resolution tend to decrease, and if it exceeds 80% by mass, a good via shape tends to be difficult to obtain.

(B) Photopolymerizable compound having an ethylenically unsaturated bond The component (B) used in the present invention is (B-1) a photopolymerizable compound having a fluorene skeleton and an oxyethylene group or oxypropylene group in the molecule. contains. As the component (B-1), a compound represented by the following general formula (1) is preferable.

In the general formula (1), R ¹ and R ² each independently represent a hydrogen atom or a methyl group.

R ³ and R ⁴ each independently represent a halogen atom, an amino group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms or an alkylamino group having 1 to 6 carbon atoms, and is dissolved in a solvent. From the viewpoint of properties, an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms is preferable, and an alkyl group having 1 to 6 carbon atoms is more preferable. The alkyl group having 1 to 6 carbon atoms, the alkoxy group having 1 to 6 carbon atoms or the alkylamino group having 1 to 6 carbon atoms may be linear or branched, and is particularly preferably branched. The hydrogen atom may be substituted with an arbitrary substituent as long as the effect is not impaired.

p and r each independently represent an integer of 0 to 4, and preferably 1 to 4 from the viewpoint of solubility in a solvent. When p or r is 2 or more, a plurality of R ³ or R ⁴ may be the same or different.

-(A-O)-and-(OB)-are each independently a (poly) oxyethylene chain, a (poly) oxypropylene chain, or a block copolymer chain or random copolymer of ethylene oxide and propylene oxide. In view of resolution, it is preferably a (poly) oxyethylene chain or a block copolymer chain or random copolymer chain of ethylene oxide and propylene oxide, and preferably a (poly) oxyethylene chain. More preferred. The propylene group in the (poly) oxypropylene chain or the copolymer chain may be linear or branched, and when it is branched, it may be —CH (CH ₃ ) CH ₂ — or —CH ₂ CH. (CH ₃₎ - it may be.

  The total number of repeating oxyethylene groups or oxypropylene groups contained in-(AO)-and-(OB)-; m + n is 1 to 20, with a good balance of resolution, crack resistance and heat resistance From the viewpoint of improving, it is preferably 2 to 15, more preferably 4 to 12, and still more preferably 5 to 10.

  Examples of photopolymerizable compounds other than the component (B-1) include bisphenol A (meth) acrylate compounds, compounds obtained by reacting polyhydric alcohols with α, β-unsaturated carboxylic acids, and glycidyl group-containing compounds. And a compound obtained by reacting an α, β-unsaturated carboxylic acid, a urethane monomer such as a (meth) acrylate compound having a urethane bond in the molecule, or a urethane oligomer. Besides these, nonylphenoxy polyoxyethylene acrylate, γ-chloro-β-hydroxypropyl-β ′-(meth) acryloyloxyethyl-o-phthalate, β-hydroxyalkyl-β ′-(meth) acryloyloxy Examples thereof include phthalic acid compounds such as alkyl-o-phthalate, (meth) acrylic acid alkyl esters, and EO-modified nonylphenyl (meth) acrylate. These may be used alone or in combination of two or more. Among these, the component (B) is (B-2) a bisphenol A (meth) acrylate compound, a compound obtained by reacting a polyhydric alcohol with an α, β-unsaturated carboxylic acid, or a urethane in the molecule. It is preferable to include one or more selected from the group consisting of (meth) acrylate compounds having a bond.

“EO” refers to “ethylene oxide”, and “PO” refers to “propylene oxide”. Further, “EO modified” means having a block structure of ethylene oxide units (—CH ₂ —CH ₂ —O—), and “PO modified” means propylene oxide units (—CH ₂ —CH ₂ —CH _2). -O-, -CH (CH ₃ ) CH ₂ -O-, -CH ₂ CH (CH ₃ ) -O-) having a block structure, and "EO / PO-modified" means ethylene oxide units and propylene It means having a block copolymer chain or random copolymer chain of oxide units.

  Examples of bisphenol A-based (meth) acrylate compounds include 2,2-bis (4-((meth) acryloxypolyethoxy) phenyl) propane and 2,2-bis (4-((meth) acryloxypolypropoxy). EO or PO-modified bisphenol A-based (meth) acrylate compounds such as) phenyl) propane and 2,2-bis (4-((meth) acryloxypolyethoxypolypropoxy) phenyl) propane. These may be used alone or in combination of two or more.

  Examples of 2,2-bis (4-((meth) acryloxypolyethoxy) phenyl) propane include 2,2-bis (4-((meth) acryloxydiethoxy) phenyl) propane, 2,2- Bis (4-((meth) acryloxytriethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxytetraethoxy) phenyl) propane, 2,2-bis (4-((meth)) Acryloxypentaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxyhexaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxyheptaethoxy) phenyl) propane 2,2-bis (4-((meth) acryloxyoctaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxy nonaethoxy) ) Phenyl) propane, 2,2-bis (4-((meth) acryloxydecaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxyundecaethoxy) phenyl) propane, 2, 2-bis (4-((meth) acryloxydodecaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxytridecaethoxy) phenyl) propane, 2,2-bis (4- ( (Meth) acryloxytetradecaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxypentadecaethoxy) phenyl) propane, and 2,2-bis (4-((meth) acryloxy) Hexadecaethoxy) phenyl) propane and the like.

  Among the above compounds, 2,2-bis (4- (methacryloxypentaethoxy) phenyl) propane is FA-321M (manufactured by Hitachi Chemical Co., Ltd., trade name) or BPE-500 (manufactured by Shin-Nakamura Chemical Co., Ltd.). , And commercially available as trade name), and 2,2-bis (4- (methacryloxypentadecaethoxy) phenyl) propane is commercially available as BPE-1300 (trade name, manufactured by Shin-Nakamura Chemical Co., Ltd.). Are available.

  Examples of 2,2-bis (4-((meth) acryloxypolypropoxy) phenyl) propane include 2,2-bis (4-((meth) acryloxydipropoxy) phenyl) propane, 2, 2-bis (4-((meth) acryloxytripropoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxytetrapropoxy) phenyl) propane, 2,2-bis (4-(( (Meth) acryloxypentapropoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxyhexapropoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxyheptapropoxy) phenyl ) Propane, 2,2-bis (4-((meth) acryloxyoctapropoxy) phenyl) propane, 2,2-bis (4-((meth)) Acryloxynonapropoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxydecapropoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxyundecapropoxy) phenyl) Propane, 2,2-bis (4-((meth) acryloxydodecapropoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxytridecapropoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxytetradecapropoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxypentadecapropoxy) phenyl) propane, and 2,2-bis (4-(( (Meth) acryloxyhexadecapropoxy) phenyl) propane and the like. These may be used alone or in combination of two or more.

  Examples of 2,2-bis (4-((meth) acryloxypolyethoxypolypropoxy) phenyl) propane include 2,2-bis (4-((meth) acryloxydiethoxyoctapropoxy) phenyl) propane, Examples include 2,2-bis (4-((meth) acryloxytetraethoxytetrapropoxy) phenyl) propane and 2,2-bis (4-((meth) acryloxyhexaethoxyhexapropoxy) phenyl) propane. . These can be used alone or in combination of two or more.

  Examples of the compound obtained by reacting a polyhydric alcohol with an α, β-unsaturated carboxylic acid include, for example, polyethylene glycol di (meth) acrylate having 2 to 14 ethylene groups and 2 to 14 propylene groups. Polyalkylene glycol di (meth) acrylates such as polypropylene glycol di (meth) acrylate, such as polyethylene / polypropylene glycol di (meth) acrylate having 2 to 14 ethylene groups and 2 to 14 propylene groups, Trimethylolpropane di (meth) acrylate, trimethylolpropane tri (meth) acrylate, EO modified trimethylolpropane tri (meth) acrylate, PO modified trimethylolpropane tri (meth) acrylate, EO / PO modified trimethylolpropane tri (meta) ) Examples include acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, and dipentaerythritol hexa (meth) acrylate. These may be used alone or in combination of two or more.

  Examples of the compound obtained by reacting a glycidyl group-containing compound with an α, β-unsaturated carboxylic acid include trimethylolpropane triglycidyl ether tri (meth) acrylate and 2,2-bis (4- (meth) acryloxy- 2-hydroxy-propyloxy) phenyl and the like. Examples of the α, β-unsaturated carboxylic acid for obtaining the above compound include (meth) acrylic acid.

  Examples of urethane monomers include (meth) acrylic monomers having an OH group at the β-position, isophorone diisocyanate, 2,6-toluene diisocyanate, 2,4-toluene diisocyanate, and 1,6-hexamethylene diisocyanate. Addition reaction products with diisocyanate compounds, tris ((meth) acryloxytetraethylene glycol isocyanate) hexamethylene isocyanurate, EO-modified urethane di (meth) acrylate, PO-modified urethane di (meth) acrylate, and EO / PO-modified urethane di (meth) ) EO such as acrylate or PO-modified urethane di (meth) acrylate compound.

  Furthermore, examples of the (meth) acrylic acid alkyl ester include (meth) acrylic acid methyl ester, (meth) acrylic acid ethyl ester, (meth) acrylic acid butyl ester, and (meth) acrylic acid 2-ethylhexyl ester. Can be mentioned. These (B) components can be used individually by 1 type or in combination of 2 or more types.

  The component (B) is a photopolymerizable compound other than the component (B-1), as described above, from the viewpoint of improving the flexibility during film formation and the crack resistance of the cured film. (B-2) Bisphenol One or two selected from the group consisting of an A-based (meth) acrylate compound, a compound obtained by reacting a polyhydric alcohol with an α, β-unsaturated carboxylic acid, or a (meth) acrylate compound having a urethane bond in the molecule Preferably it contains more than one species.

  The content ratio of the component (B-1) in the photosensitive resin composition of the present invention is based on the mass of the entire component (B) from the viewpoint of improving the flexibility during film formation and the crack resistance of the cured film. 1 to 50% by mass, more preferably 2 to 40% by mass, further preferably 3 to 30% by mass, and particularly preferably 5 to 20% by mass.

  Furthermore, it is preferable that content of the whole (B) component in the photosensitive resin composition of this invention is 15-50 mass% on the basis of the solid content whole quantity of (A) component and (B) component, 20 More preferably, it is -45 mass%, and it is especially preferable that it is 25-40 mass%. If this content is less than 15% by mass, good sensitivity and resolution tend to be difficult to obtain, and if it exceeds 50% by mass, the tackiness of the surface tends to deteriorate, and a good via shape tends to be difficult to obtain. is there.

(C) Photopolymerization initiator As the component (C) used in the present invention, for example, 4,4′-bis (diethylamine) benzophenone, benzophenone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -Butanone-1, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propanone-1 and other aromatic ketones, quinones such as alkylanthraquinones, benzoin compounds such as benzoin and alkylbenzoin, benzoin Benzoin ether compounds such as alkyl ethers, benzyl derivatives such as benzyldimethyl ketal, 2- (o-chlorophenyl) -4,5-diphenylimidazole dimer, 2- (o-chlorophenyl) -4,5-di (methoxyphenyl) ) Imidazole dimer, 2- (o-fluorophenyl) -4 2,4 such as 5-diphenylimidazole dimer, 2- (o-methoxyphenyl) -4,5-diphenylimidazole dimer, 2- (p-methoxyphenyl) -4,5-diphenylimidazole dimer , 5-triarylimidazole dimer, N-phenylglycine, N-phenylglycine derivative, 7-diethylamino-4-methylcoumarin and other coumarin compounds, bis (2,4,6-trimethylbenzoyl) -phenylphosphine Such as oxide (Ciba Specialty Chemicals, product name “IRGACURE-819”), 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (Ciba Specialty Chemicals, product name “DAROCUR-TPO”), etc. Acylphosphine oxide compounds, 1 -Phenyl-1,2-propanedione-2 (o-ethoxycarbonyl) oxime, 1,2-octanedione-1- [4- (phenylthio) phenyl] -2- (o-benzoyloxime) (Ciba Specialty Chemicals Co., Ltd.) Product name "IRGACURE-OXE01"), 1- [9-ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl] ethanone 1- (o-acetyloxime) (Ciba Specialty Chemicals Co., Ltd.) Oxime ester compounds such as “IRGACURE-OXE02” manufactured by company, 9-phenylacridine, 1,7-bis (9,9′-acridinyl) heptane (product name “N-1717” manufactured by ADEKA CORPORATION) ) And the like. The two aryl substituents of the 2,4,5-triarylimidazole dimer may give the same and symmetric compounds or differently give asymmetric compounds. These can be used alone or in combination of two or more.

  The component (C) used in the present invention preferably contains an acyl phosphine oxide compound from the viewpoint of obtaining a better via shape, and is represented by bis (2, 4, 4) represented by the following formula (3). It is particularly preferred to include 6-trimethylbenzoyl) -phenylphosphine oxide. Bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide is commercially available as IRGACURE-819 (product name, manufactured by Ciba Specialty Chemicals Co., Ltd.).

  By containing the bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide represented by the above formula (3), the photosensitive resin composition of the present invention is more excellent in transparency, and is a solder resist. As a result, a better via shape can be obtained.

  Moreover, content of (C) component in the photosensitive resin composition of this invention is 0.1-10 mass parts with respect to 100 mass parts of solid content total amount of (A) component and (B) component. Is preferable, it is more preferable that it is 0.5-6 mass parts, and it is especially preferable that it is 1-5 mass parts. If this content is less than 0.1 parts by mass, good sensitivity and resolution tend to be difficult to obtain, and if it exceeds 10 parts by mass, a good via shape tends to be difficult to obtain.

(D) Thermosetting agent As the component (D) used in the present invention, for example, a thermosetting agent that itself crosslinks by heating, that is, a curing agent that forms a polymer network structure by applying heat, or by heating (A) The hardening | curing agent etc. which react with the carboxyl group of a component and form a three-dimensional structure are mentioned.

  Examples of the thermosetting agent that itself crosslinks by heating include a bismaleimide compound.

  Examples of the bismaleimide compound include 1,6-bis (N-malemidyl) -2,2,4-trimethylhexane, m-di-N-malemidylbenzene, and bis (4-N-malemidylphenyl). ) Methane, 2,2-bis (4-N-maleimidylphenyl) propane, 2,2-bis (4-N-maleimidyl 2,5-dibromophenyl) propane, 2,2-bis [(4-N Examples thereof include various bismaleimide compounds such as -malemidylphenoxy) phenyl] propane and 2,2-bis [(4-N-malemidyl-2-methyl-5-ethylphenyl) propane. These bismaleimide compounds may be used alone or as a modified product with various resins. Among these, a bismaleimide compound having an aromatic ring is preferable from the viewpoint of heat resistance of the cured film. These can be used individually by 1 type or in combination of 2 or more types.

  The bismaleimide compound may be a commercially available product such as BMI-1000, BMI-2000, BMI-3000, BMI-4000, BMI-5100, BMI-7000, BMI-TMH (above, manufactured by Daiwa Kasei Kogyo Co., Ltd., Product name) etc. are commercially available.

  Moreover, as a hardening | curing agent which reacts with the carboxyl group of (A) component by heating and forms a three-dimensional structure, a block isocyanate compound is mentioned, for example.

  Examples of the blocked isocyanate compound include polyisocyanate compounds blocked with a blocking agent such as an alcohol compound, a phenol compound, ε-caprolactam, an oxime compound, and an active methylene compound. The dissociation temperature of the blocking agent is preferably 120 to 200 ° C. These can be used individually by 1 type or in combination of 2 or more types.

  Examples of the polyisocyanate compound to be blocked include 4,4-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, naphthalene 1,5-diisocyanate, o-xylene diisocyanate, m-xylene diisocyanate, Aromatic polyisocyanates such as 2,4-tolylene dimer, aliphatic polyisocyanates such as hexamethylene diisocyanate, 4,4-methylenebis (cyclohexyl isocyanate), isophorone diisocyanate, and alicyclic polyisocyanates such as bicycloheptane triisocyanate. An aromatic polyisocyanate is preferable from the viewpoint of heat resistance, and an aliphatic polyisocyanate or an alicyclic polyisocyanate is preferable from the viewpoint of preventing coloring. These can be used individually by 1 type or in combination of 2 or more types.

  Commercially available products may be used as the above-mentioned blocked isocyanate compound, Sumidur BL-3175, Desmodur TPLS-2957, TPLS-2062, TPLS-2957, TPLS-2078, BL4165, TPLS2117, BL1100, BL1265, Desmotherm 2170, Desmotherm 2265. (Trade name) manufactured by Sumitomo Bayer Urethane Co., Ltd., Coronate 2512, Coronate 2513, Coronate 2520 (trade name, manufactured by Nippon Polyurethane Industry Co., Ltd.), B-830, B-815, B-846, B-870, B- 874, B-882 (trade name, manufactured by Mitsui Takeda Chemical Co., Ltd.) and the like.

  From the viewpoint of improving the heat resistance, crack resistance and HAST resistance of the cured film, the content of the component (D) in the photosensitive resin composition of the present invention is the total solid content of the components (A) and (B). As a reference, it is preferably 0.1 to 20% by mass, more preferably 0.5 to 15% by mass, and further preferably 1 to 10 parts by mass.

(E) Sensitizer The photosensitive resin composition of the present invention preferably further contains (E) a sensitizer. Examples of the component (E) include pyrazoline, anthracene, coumarin, xanthone, thioxanthone, oxazole, benzoxazole, thiazole, benzothiazole, triazole, stilbene, triazine, thiophene, Naphthalimide type, triarylamine type compounds and the like can be mentioned. These can be used alone or in combination of two or more.

  The component (E) preferably contains a thioxanthone compound from the viewpoint of obtaining a better via shape. Examples of the thioxanthone compound include 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, and the like. It is particularly preferable to contain 2,4-diethylthioxanthone represented by the following formula (4). 2,4-Diethylthioxanthone is commercially available as KAYACURE-DETX (manufactured by Nippon Kayaku Co., Ltd., product name).

  By containing 2,4-diethylthioxanthone represented by the above formula (4), the photosensitive resin composition of the present invention can have higher sensitivity to exposure light.

  Moreover, it is preferable that content of (E) component in the photosensitive resin composition of this invention is 0.01-10 mass% on the basis of the solid content whole quantity of (A) component and (B) component, More preferably, it is 0.05-5 mass%, and it is especially preferable that it is 0.1-2 mass%. If this content is less than 0.01% by mass, good sensitivity and resolution tend to be difficult to obtain, and if it exceeds 10% by mass, a good via shape tends to be difficult to obtain.

  Moreover, the photosensitive resin composition of this invention may contain a thermal-polymerization initiator as needed in the range which does not inhibit the effect show | played by the said structure.

  As the thermal polymerization initiator, known ones can be used, for example, benzoyl peroxide, ketone peroxides such as methyl ethyl ketone peroxide, alkyl peroxides such as tertiary butyl peroxide, and peroxydicarbonates. Peroxyketals, peroxyesters, alkyl peresters, and the like can be used. These can be used individually by 1 type or in combination of 2 or more types.

  When the photosensitive resin composition contains a thermal polymerization initiator, the content is from the viewpoint of improving various properties such as heat resistance, crack resistance, HAST resistance and the like of the cured film (A) component and (B). It is preferably 0.01 to 10% by mass, more preferably 0.1 to 8% by mass, and still more preferably 0.5 to 5% by mass, based on the total solid content of the components.

  Moreover, you may add a filler in the photosensitive resin composition in order to improve various characteristics, such as the heat resistance of a cured film, crack resistance, and HAST resistance.

  Examples of the filler include silica, fused silica, talc, alumina, hydrated alumina, barium sulfate, aluminum hydroxide, magnesium hydroxide, calcium hydroxide, aerosil, calcium carbonate and other inorganic fine particles, powdered epoxy resin, powdered Examples thereof include organic fine particles such as polyimide particles, and powdered Teflon (registered trademark) particles. These fillers may be subjected to a coupling treatment in advance. These can be used individually by 1 type or in combination of 2 or more types.

  Examples of the method for dispersing the filler in the photosensitive resin composition include known kneading methods such as a kneader, ball mill, bead mill, and three rolls.

  When the photosensitive resin composition contains a filler, the content thereof is a solid of the component (A) and the component (B) from the viewpoint of improving various properties such as heat resistance, crack resistance and HAST resistance of the cured film. It is preferably 1 to 50% by mass, more preferably 3 to 40% by mass, and further preferably 5 to 30% by mass based on the total amount of the components.

  In addition, the photosensitive resin composition of this invention may contain components other than the above-mentioned (A)-(E) component as needed. Such components include photopolymerizable compounds having at least one cationically polymerizable cyclic ether group in the molecule (such as oxetane compounds), cationic polymerization initiators, dyes such as malachite green, tribromophenylsulfone, leucocrystals. Photo-coloring agents such as violet, thermo-coloring inhibitors, plasticizers such as p-toluenesulfonamide, pigments, fillers, antifoaming agents, flame retardants, stabilizers, adhesion-imparting agents, leveling agents, peeling accelerators, oxidation Examples thereof include an inhibitor, a fragrance, an imaging agent, a thermal crosslinking agent, an inorganic and / or organic filler. These should just be added to such an extent that the achievement of the object of the present invention is not hindered, and each is added in an amount of about 0.01 to 20% by mass based on the total solid content of the component (A) and the component (B). Can do. These are used alone or in combination of two or more.

  In addition, the photosensitive resin composition of the present invention may contain a solvent such as methanol, ethanol, acetone, methyl ethyl ketone, methyl cellosolve, ethyl cellosolve, toluene, N, N-dimethylformamide, propylene glycol monomethyl ether, or the like as necessary. It is good also as a solution about 30-60 mass% of solid content by melt | dissolving in a mixed solvent. This solution can be used as a coating solution for forming the photosensitive layer of the photosensitive element.

  The above coating solution may be used for forming a photosensitive layer of a photosensitive element by coating and drying on a support described later. For example, the surface of a metal plate, for example, copper, copper-based You may apply | coat and use as a liquid resist on the surface of iron-type alloys, such as an alloy, nickel, chromium, iron, and stainless steel, Preferably copper, a copper-type alloy, and an iron-type alloy.

(Photosensitive element)
Next, the photosensitive element of the present invention will be described. FIG. 1 is a schematic cross-sectional view showing a preferred embodiment of the photosensitive element of the present invention. A photosensitive element 1 shown in FIG. 1 includes a support film (support) 10 and a photosensitive layer 20 made of a photosensitive resin composition formed on the support film 10. You may further provide the protective film 30 which coat | covers it on top.

  As the support film 10, for example, a polymer film having heat resistance and solvent resistance such as polyethylene terephthalate, polypropylene, polyethylene, and polyester can be used. The thickness of the support film 10 (polymer film) is preferably 5 to 25 μm. If the thickness is less than 5 μm, the support film 10 tends to be broken when the support film 10 before development is peeled off. If it exceeds 25 μm, the resolution tends to decrease. In addition, you may use the support film 10 laminated | stacked on both surfaces of the photosensitive layer 20, one as a support body of the photosensitive layer 20, and another as the protective film 30 of the photosensitive resin composition.

  As the protective film 30, for example, a polymer film having heat resistance and solvent resistance such as polyester such as polyethylene terephthalate, polypropylene, and polyethylene can be used. Examples of commercially available products include polypropylene film such as product names “Alphan MA-410” and “E-200C” manufactured by Oji Paper Co., Ltd., Shin-Etsu Film Co., Ltd., and product name “PS-” manufactured by Teijin Limited. Polyethylene terephthalate film such as PS series such as “25” can be mentioned, but is not limited thereto. The thickness of the protective film is preferably 1 to 100 μm, more preferably 5 to 50 μm, still more preferably 5 to 30 μm, and particularly preferably 15 to 30 μm. If this thickness is less than 1 μm, the protective film tends to be broken during lamination, and if it exceeds 100 μm, the cost tends to be inferior. The protective film 30 preferably has a smaller adhesive strength between the photosensitive layer 20 and the protective film 30 than the adhesive strength between the photosensitive layer 20 and the support film 10, and is preferably a low fisheye film. Fisheye is a material in which foreign materials, undissolved materials, oxidatively deteriorated materials, etc. are incorporated into the film when the material is melted and kneaded, extruded, biaxially stretched, or casted to produce a film. It is.

  The photosensitive layer 20 is prepared by dissolving the photosensitive resin composition of the present invention in a solvent as described above to obtain a solution (coating solution) having a solid content of about 30 to 60% by mass, and then the solution (coating solution). It is preferable to form by coating on the support film 10 and drying. The application can be performed by a known method using, for example, a roll coater, comma coater, gravure coater, air knife coater, die coater, bar coater or the like. Moreover, the said drying can be performed at 70-150 degreeC and about 5 to 30 minutes. The amount of the remaining organic solvent in the photosensitive resin composition is preferably 2% by mass or less based on the total amount of the photosensitive resin composition from the viewpoint of preventing the diffusion of the organic solvent in the subsequent step. The thickness of the photosensitive layer 20 varies depending on the application, but is preferably 1 to 100 μm, more preferably 5 to 50 μm, and particularly preferably 10 to 40 μm after drying. If the thickness is less than 1 μm, there is a tendency that it is difficult to apply industrially.

  The photosensitive layer 20 preferably has an absorbance with respect to ultraviolet rays having a wavelength of 365 nm of 0.1 to 3, more preferably 0.15 to 2, and particularly preferably 0.2 to 1.5. preferable. If the absorbance is less than 0.1, the sensitivity tends to be inferior, and if it exceeds 3, the adhesion tends to be inferior. The absorbance can be measured by a UV spectrometer, and examples of the UV spectrometer include a 228A type (manufactured by Hitachi, Ltd., product name) W beam spectrophotometer.

  The photosensitive element 1 may further include an intermediate layer such as a cushion layer, an adhesive layer, a light absorption layer, and a gas barrier layer. Moreover, the obtained photosensitive element 1 can be wound up and stored in a sheet form or a roll around a core. In addition, it is preferable to wind up so that a support body may become the outermost part in this case. An end face separator is preferably installed on the end face of the roll-shaped photosensitive element 1 roll from the viewpoint of end face protection, and a moisture-proof end face separator is preferably installed from the viewpoint of edge fusion resistance. Moreover, as a packing method, it is preferable to wrap and package in a black sheet with low moisture permeability. Examples of the winding core include plastics such as polyethylene resin, polypropylene resin, polystyrene resin, polyvinyl chloride resin, and ABS resin (acrylonitrile-butadiene-styrene copolymer).

(Method for forming resist pattern)
Next, a resist pattern forming method using the photosensitive element 1 of the present invention will be described.

  A photosensitive layer made of the above-described photosensitive resin composition is formed on a substrate on which a resist is to be formed. The protective film 30 of the photosensitive element 1 is peeled off from the photosensitive layer 20, and the exposed surface of the photosensitive layer 20 is adhered by a laminate or the like so as to cover a conductor layer having a circuit pattern formed on the substrate. A method of laminating under reduced pressure is also preferable from the viewpoint of improving adhesion and followability. In addition, the photosensitive resin composition can also be apply | coated on a board | substrate by well-known methods, such as the method of apply | coating the varnish of the photosensitive resin composition with a screen printing method or a roll coater.

  Next, the photosensitive layer is irradiated with actinic rays through a mask pattern having a predetermined pattern shape, and a predetermined region of the photosensitive layer is photocured (mask exposure method). At this time, when the support film 10 present on the photosensitive layer 20 is transparent to the active light, the active light can be irradiated through the support film 10, and when the support film 10 is light-shielding. After the support film 10 is removed, the photosensitive layer 20 can be irradiated with actinic rays.

  Examples of the active light source include known light sources such as carbon arc lamps, mercury vapor arc lamps, ultrahigh pressure mercury lamps, high pressure mercury lamps, xenon lamps, semiconductor lasers such as blue-violet lasers, and solid-state lasers such as YAG lasers. Can be used that effectively radiate. Moreover, what can radiate | emit visible light effectively, such as a flood bulb for photography, a solar lamp, can be used.

  Further, when a support is present on the photosensitive layer, after removing the support, by removing a portion that has not been photocured by wet development or dry development (unexposed portion) and developing, A resist pattern can be formed.

  In the case of the above-described wet development, as the developer, an alkaline aqueous solution, an aqueous developer, an organic solvent, or the like that is safe and stable and has good operability is used according to the type of the photosensitive resin composition. Further, as a developing method, a known method such as spraying, rocking dipping, brushing, scraping or the like is appropriately employed.

  Examples of the base of the alkaline aqueous solution include alkali metals such as lithium hydroxide, sodium hydroxide and potassium hydroxide which are hydroxides of lithium, sodium and potassium, carbonates or bicarbonates such as alkali metals and ammonium. Alkaline carbonate or bicarbonate, alkali metal phosphate sodium phosphate, potassium phosphate, etc., alkali metal pyrophosphate sodium pyrophosphate, potassium pyrophosphate etc., safe and stable, operability The one with good is used.

  Examples of the alkaline aqueous solution include a dilute solution of 0.1 to 5% by mass sodium carbonate, a dilute solution of 0.1 to 5% by mass potassium carbonate, and a dilute solution of 0.1 to 5% by mass sodium hydroxide. A solution, a dilute solution of 0.1 to 5% by mass sodium tetraborate is preferred, and the pH is preferably in the range of 9 to 11. The temperature of the alkaline aqueous solution is adjusted according to the developability of the photosensitive layer 20 and is preferably 20 to 50 ° C. Furthermore, a small amount of an organic solvent such as a surfactant or an antifoaming agent may be mixed in the alkaline aqueous solution in order to promote development.

  As the aqueous developer, one comprising water and an alkaline aqueous solution or one or more organic solvents is used. Here, as the base of the alkaline aqueous solution, in addition to those described above, for example, borax, sodium metasilicate, tetramethylammonium hydroxide, ethanolamine, ethylenediamine, diethylenetriamine, 2-amino-2-hydroxymethyl-1,3- Examples include propanediol, 1,3-diaminopropanol-2, and morpholine. The pH of such an aqueous developer is preferably as small as possible within a range where development processing can be sufficiently performed, preferably pH 8 to 12, and more preferably pH 9 to 10.

  Examples of the organic solvent include acetone, ethyl acetate, alkoxyethanol having an alkoxy group having 1 to 4 carbon atoms, ethyl alcohol, isopropyl alcohol, butyl alcohol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, and diethylene glycol monobutyl ether. . The concentration of such an organic solvent is usually preferably 2 to 90% by mass. Moreover, the temperature of such an organic solvent can be adjusted according to developability. Such organic solvents can be used alone or in combination of two or more. Examples of the organic solvent-based developer used alone include 1,1,1-trichloroethane, N-methylpyrrolidone, N, N-dimethylformamide, cyclohexanone, methyl isobutyl ketone, and γ-butyrolactone. Furthermore, a small amount of an organic solvent such as a surfactant or an antifoaming agent may be mixed in the alkaline aqueous solution in order to promote development. The organic solvent is preferably added with water in the range of 1 to 20% by mass to prevent ignition.

  In the method for forming a resist pattern of the present invention, if necessary, two or more kinds of development methods described above may be used in combination. Development methods include a dip method, a battle method, a spray method, a high-pressure spray method, brushing, and slapping, and the high-pressure spray method is most suitable for improving resolution. For the etching of the metal surface performed after development, for example, a cupric chloride solution, a ferric chloride solution, an alkaline etching solution, or the like can be used.

(Solder resist)
Next, a preferred embodiment of the solder resist of the present invention using the photosensitive element 1 of the present invention will be described. After completion of the development step, it is preferable to further irradiate the resist pattern with ultraviolet rays or heat with a high-pressure mercury lamp for the purpose of improving the solder heat resistance and chemical resistance of the resist pattern. When irradiating with ultraviolet rays, it is preferable to adjust the irradiation amount as necessary. For example, irradiation can be performed at an irradiation amount of about 0.2 to 10 J / cm ² . Moreover, when heating a resist pattern, it is preferable to carry out on the conditions for about 15 to 90 minutes in the range of about 100-170 degreeC.

  Both ultraviolet irradiation and heating may be performed. In this case, both may be performed at the same time, and after either one is performed, the other may be performed. When performing ultraviolet irradiation and heating simultaneously, it is preferable to heat to 60-150 degreeC from a viewpoint of providing solder heat resistance and chemical resistance more favorably.

  The solder resist formed in this way is used, for example, as a plating resist or etching resist when plating or etching a substrate, and is left on the substrate as it is to protect wiring and the like. Used as a protective film (solder resist).

  Further, in the above-described exposure step, when exposure is performed using a mask having a pattern in which a predetermined portion of the conductor layer is unexposed, the unexposed portion is removed and formed on the substrate by developing the mask. Thus, a resist having an opening pattern in which a part of the conductive layer exposed is obtained. Thereafter, it is preferable to perform a process necessary for forming the above-described solder resist.

  The present invention has been described in detail based on the embodiments. However, the present invention is not limited to the above embodiment. The present invention can be variously modified without departing from the gist thereof.

  Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. However, the present invention is not limited to these examples.

(Examples 1-2 and Comparative Examples 1-2)
(Preparation of photosensitive resin composition)
Table 1 shows the blending amounts (parts by mass) of the components (A) to (E) and the solvent used in Examples and Comparative Examples. Based on the composition shown in Table 1, a solution of the photosensitive resin composition was prepared.

The details of each component in Table 1 are as follows.
(A-1): A copolymer of methacrylic acid / methyl methacrylate / ethyl acrylate (12/58/30 (mass ratio), weight average molecular weight 70000, acid value 78 mgKOH / g)
(B1): Bisphenoxy fluorange methacrylate (total number of repeating oxyethylene groups; m + n = 1) (Osaka Gas Chemical Co., Ltd., product name “EA-200”)
(B2) Bisphenoxy fluorange methacrylate (total number of repeating oxyethylene groups; m + n = 4) (manufactured by Osaka Gas Chemical Co., Ltd., product name “EA-1000”)
FA-321M: 2,2-bis (4- (methacryloxypentaethoxy) phenyl) propane (manufactured by Hitachi Chemical Co., Ltd., product name “FA-321M”)
I-819: Bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide (manufactured by Ciba Specialty Chemicals, product name “IRGACURE-819”)
DETX: 2,4-diethylthioxanthone (manufactured by Nippon Kayaku Co., Ltd., product name “KAYACURE-DETX”)
BL-3175SN: Block isocyanate (manufactured by Sumika Bayer Urethane Co., Ltd., product name “Death Module BL-3175SN”)

(Production of photosensitive element)
The obtained photosensitive resin composition solution was uniformly coated on a 16 μm-thick polyethylene terephthalate film (product name “HTF01”, manufactured by Teijin Ltd.) as a support, and hot air convection at 80 ° C. and 125 ° C. A photosensitive layer made of a photosensitive resin composition was formed by drying with a dryer (feed rate: 3.1 m / min, length of drying oven: 3 m each). The film thickness after drying of the photosensitive layer was 30 μm. Subsequently, a polyethylene film (manufactured by Teijin Limited, product name “NF-15”) was attached as a protective film covering the photosensitive layer to obtain a photosensitive element.

(Preparation of evaluation laminate)
The copper surface of a glass cloth base epoxy resin double-sided copper clad laminate (Hitachi Kasei Kogyo Co., Ltd., product name “MCL-E-679” having a copper foil thickness of 18 μm and a copper foil layer on both sides) is designated as CZ10. Chemical roughening was performed under the conditions of a processing temperature of 35 ° C., a spray pressure of 0.2 MPa, and an etching amount of 2.0 μm using a processing machine (manufactured by MEC Co., Ltd.). The polyethylene film of the photosensitive element is peeled off from the copper surface of the obtained copper-clad laminate, and press heat is applied using a press-type vacuum laminator (product name “MVLP-500” manufactured by Meiki Seisakusho Co., Ltd.). A laminate for evaluation was obtained by thermocompression bonding under conditions of a plate temperature of 70 ° C., a vacuuming time of 20 seconds, a laminating press time of 30 seconds, an atmospheric pressure of 4 hPa or less, and a pressure bonding pressure of 0.4 MPa.

(Evaluation of photosensitive element)
The following tests were performed using the photosensitive elements of Examples 1 and 2 and Comparative Examples 1 and 2, respectively, and the sensitivity, glass transition temperature (Tg), alkali developability, and vias when each photosensitive element was used. The shape, crack resistance and HAST resistance were evaluated. The results are shown in Table 2.

<Sensitivity>
On the evaluation laminate, the density region is 0.00 to 2.00, the density step is 0.05, the size of the tablet (rectangle) is 20 mm × 187 mm, and the size of each step (rectangle) is 3 mm × 12 mm. Using a photo tool having a 41-step tablet as a negative, with an energy amount such that the number of remaining step steps after development of the 41-step tablet is 14, using an EXM-1201 type exposure machine manufactured by Oak Manufacturing Co., Ltd. Exposure was performed. The exposure amount at which the number of remaining steps was 14 was defined as the sensitivity of the photosensitive layer (unit: mJ / cm ² ). A lower value indicates higher photosensitivity.

<Glass transition temperature (Tg)>
Each photosensitive element was exposed under the same conditions as described above, and the photosensitive layer was cured to form a cured film on the support. The glass transition temperature (Tg) of the cured film was measured using TMA (manufactured by Seiko Instruments Inc.) under the conditions of a heating rate of 10 ° C./min, a measurement range of 25 to 350 ° C., a sample width of 2 mm, and a weight of 5 g.

<Alkali developability>
The laminate for evaluation exposed under the above exposure conditions was allowed to stand at room temperature (25 ° C.) for 1 hour, and then the polyethylene terephthalate on the laminate was peeled off, and the minimum development time was 1% by weight aqueous sodium carbonate solution at 30 ° C. Spray development was performed in twice as long as the above. Thereby, the pattern formed by hardening the photosensitive resin composition layer was formed. The minimum development time is the minimum time required for the unexposed area to be removed by the developer. A shorter minimum development time (MD) indicates better alkali developability.

<Via shape>
Exposure was performed under the above exposure conditions using a phototool having a circular opening pattern with a diameter of 30 μm to 200 μm as an evaluation negative. Subsequently, after development under the above-described development conditions, ultraviolet irradiation is performed with an energy amount of 1 J / cm ² using an ultraviolet irradiation apparatus manufactured by Oak Manufacturing Co., Ltd., and further, heat treatment is performed at 160 ° C. for 60 minutes, thereby forming a circular shape. The board | substrate for evaluation which has a soldering resist in which the opening part of was formed was obtained.

  About the said board | substrate for evaluation, the shape (via shape) of the circular opening part of diameter 80 micrometers formed in the soldering resist was observed using the scanning electron microscope (the Keyence Corporation make, product name "VE-8800"). 2A is a schematic sectional view showing an example of a solder resist whose via shape is a “forward taper” shape, and FIG. 2B is a schematic diagram showing an example of a solder resist whose via shape is a “straight” shape. It is sectional drawing, (c) is a schematic cross section which shows an example of the solder resist whose via shape is an "undercut" shape, (d) is an example of the solder resist whose via shape is an "overhang" shape It is a schematic cross section shown. In FIG. 2, 2 is a board | substrate provided with a soldering resist, 21 is a conductor layer, 22 is a glass epoxy base material, 23 shows an opening part. The via shape is preferably a “forward taper” shape as shown in FIG. 2A or a “straight” shape as shown in FIG. 2B from the viewpoint of solder adhesion. Reverse taper shape, such as “undercut” shown in FIG. 2 (c), and the upper part of the resist of the pattern protruding from the undeveloped residue, and “overhang” shown in (d). If this is the case, the solder adhesion may deteriorate during soldering, which is not preferable.

<Crack resistance>
The substrate for evaluation having the solder resist produced in the same manner as described above was exposed to the atmosphere at −65 ° C. for 15 minutes, then heated at a rate of temperature increase of 180 ° C./min, and then in the atmosphere at 150 ° C. Then, the test was repeated 500 times with a thermal cycle in which the temperature was lowered at a rate of 180 ° C./min. After the test, the crack and the degree of peeling of the solder resist (permanent resist film) on the evaluation substrate were observed with an optical microscope (manufactured by Keyence Corporation, product name “VHX-100”) and evaluated according to the following criteria.
“◯”: No cracking or peeling of solder resist was observed “×”: No cracking or peeling of solder resist was observed

<HAST resistance>
Etching was performed on the copper surface of a printed wiring board substrate (product name “MCL-E-679”, manufactured by Hitachi Chemical Co., Ltd.) in which an 18 μm-thick copper foil was laminated on a glass epoxy substrate, and the line / space was 28 μm / A comb-shaped electrode on the same surface facing each other was formed, and this was used as an evaluation wiring board.

On the comb-shaped electrode in this evaluation wiring board, a solder resist made of a cured resist was formed in the same manner as the above-described evaluation laminate, and this was used as an electric corrosion resistance evaluation substrate. This electric corrosion resistance evaluation substrate was exposed to a super accelerated high temperature and high humidity life test (HAST) bath for 100 hours under the conditions of 130 ° C., 85% and 50V. After the test, the degree of migration in the solder resist of each evaluation substrate was observed with an optical microscope (manufactured by Keyence Corporation, product name “VHX-100”) and evaluated according to the following criteria. Migration is a phenomenon in which discoloration of the solder resist around the electrode and a decrease in insulation resistance occur when copper is eluted and deposited from the copper electrode to the solder resist.
“○”: The migration could not be confirmed in the solder resist “×”: The migration could be confirmed in the solder resist

  As shown in Table 2, the films of Examples 1 and 2 using the photosensitive resin composition of the present invention containing the components (A) to (D) have sufficient via shape, crack resistance and HAST resistance. It was excellent. On the other hand, Comparative Example 1 having no component (B-1) is inferior to Examples in terms of via shape, crack resistance and HAST resistance, and Comparative Example 2 having no component (D) is Tg. The crack resistance and HAST resistance were inferior.

DESCRIPTION OF SYMBOLS 1 ... Photosensitive element, 10 ... Support body (support film), 20 ... Photosensitive layer (photosensitive resin composition layer), 30 ... Protective film,
DESCRIPTION OF SYMBOLS 2 ... Board | substrate provided with solder resist, 21 ... Conductor layer, 22 ... Glass epoxy base material, 23 ... Opening part, 24 ... Solder resist.

Claims (11)

A photosensitive resin composition for solder resist,
(A) a binder polymer;
(B) a photopolymerizable compound having an ethylenically unsaturated bond;
(C) a photopolymerization initiator;
(D) a thermosetting agent;
The (A) binder polymer has a structural unit based on (meth) acrylic acid and (meth) acrylic acid alkyl ester, and the (B) component is (B-1) a fluorene skeleton in the molecule. And a photosensitive resin composition comprising a photopolymerizable compound having an oxyethylene group or an oxypropylene group. The photosensitive resin composition according to claim 1, wherein the component (B-1) is a compound represented by the following general formula (1).

[In General Formula (1), R ¹ and R ² each independently represent a hydrogen atom or a methyl group, and R ³ and R ⁴ each independently represent a halogen atom, an amino group, an alkyl group having 1 to 6 carbon atoms, A C1-C6 alkoxy group or a C1-C6 alkylamino group is shown, p and r show the integer of 0-4 each independently. When p or r is 2 or more, a plurality of R ³ or R ⁴ may be the same or different. -(A-O)-and-(OB)-are each independently a (poly) oxyethylene chain, a (poly) oxypropylene chain, or a block copolymer chain or random copolymer of ethylene oxide and propylene oxide. Represents a chain, and the total number of repeating oxyethylene groups or oxypropylene groups contained in-(AO)-and-(OB)-; m + n is 1-20. ]   The component (B) has (B-2) a bisphenol A-based (meth) acrylate compound, a compound obtained by reacting a polyhydric alcohol with an α, β-unsaturated carboxylic acid, or a urethane bond in the molecule (meta 3) The photosensitive resin composition of Claim 1 or 2 containing the 1 type (s) or 2 or more types chosen from the group which consists of an acrylate compound.   (E) The photosensitive resin composition in any one of Claims 1-3 which further contains a sensitizer. The photosensitive resin composition of Claim 4 whose content of the said (E) component is 0.01-20 mass% on the basis of the solid content whole quantity of (A) component and (B) component. The photosensitive resin composition in any one of Claims 2-5 whose said (B-1) component is 1-40 mass% on the basis of the mass of the whole (B) component. The photosensitive resin composition in any one of Claims 1-6 in which the said (C) component contains an acyl phosphine oxide type compound. The photosensitive resin composition in any one of Claims 4-7 in which the said (E) component contains a thioxanthone type compound. A photosensitive element provided with a support body and the photosensitive resin composition layer which consists of a photosensitive resin composition in any one of Claims 1-8 formed on this support body. The soldering resist which consists of a photocured material of the photosensitive resin composition in any one of Claims 1-8 formed on the board | substrate for printed wiring boards. A printed wiring board comprising: a printed wiring board substrate; and a solder resist made of a photocured product of the photosensitive resin composition according to claim 1 formed on the printed wiring board substrate.

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