JP5126354B2 - 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 photosensitive solder resist that can be produced is required.

  The solder resist generally requires characteristics such as developability, high resolution, insulation, solder heat resistance, and gold plating resistance. In particular, for solder resists for semiconductor package substrates, in addition to the above characteristics, for example, crack resistance against a temperature cycle test (TCT) of −55 to 150 ° C., and super accelerated high temperature between fine wirings. There is a demand for HAST resistance to a high humidity life test (HAST).

  The solder resist has a fine opening pattern in which a part of the conductor layer having the wiring pattern is exposed. From the viewpoint of solder adhesion, the opening shape (via shape) of the opening (via hole) is A forward tapered shape is required. 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-part type photosensitive resin composition in which a curable epoxy resin and a photosensitive prepolymer containing a carboxylic acid group for imparting alkali developability are separately provided. Is 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). .

  However, the conventional liquid photosensitive resin composition has excellent solder heat resistance among the characteristics required for solder resists, but the cured product tends to be brittle and has insufficient crack resistance. There was a problem of being. In order to improve crack resistance, a method of adding an elastomer to the photosensitive resin composition is known (see, for example, Patent Document 2).

On the other hand, in recent years, a dry film type solder resist has attracted attention from the viewpoint of improving film thickness uniformity, surface smoothness, thin film forming property, 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, a photosensitive resin composition having excellent storage stability, which is difficult to achieve with the conventional two-component type photosensitive resin composition, capable of alkali development, and excellent in chemical resistance, heat resistance, etc. Products have been developed (see, for example, Patent Document 3).
JP-A 61-243869 JP 2002-162738 A JP 2005-316431 A

  However, the solder resist obtained from the conventional photosensitive resin composition is susceptible to contamination by the metal constituting the circuit at high temperature and high humidity, and it is difficult to maintain the properties such as insulation over a long period of time. However, sufficient HAST resistance was not obtained. In recent years, further improvements in crack resistance and HAST resistance have been demanded for solder resists.

  Moreover, in the solder resist obtained from the conventional photosensitive resin composition, it is not fully realized to obtain a good via shape having a high resolution and a forward taper shape.

  The present invention has been made in view of the above problems, and when a solder resist is formed on a printed wiring board, a good via shape can be obtained, and excellent crack resistance and HAST resistance are excellent. It is an object to provide a photosensitive resin composition, a photosensitive element using the same, a solder resist, and a printed wiring board.

  As a result of intensive studies in view of the above problems, the present inventors can solve the above problems by including a specific photopolymerizable compound as the component (B) in the photosensitive resin composition. I found out.

That is, 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 sensitizer. Wherein the component (B) is (B-1) a photopolymerizable compound represented by the following general formula (1), and (B-2) a light represented by the following general formula (2). A polymerizable compound and (B-3) a photopolymerizable compound having three or more ethylenically unsaturated bonds.
[In Formula (1), R ¹ and R ² each independently represent a hydrogen atom or a methyl group. A and B each independently represent an alkylene group having 1 to 6 carbon atoms, m ₁ and m ₂ each independently represents an integer of 1 to 20, and m ₁ + m ₂ is 4 to 40. ]
[In Formula (2), X represents a divalent organic group containing an alicyclic skeleton, and R ³ and R ⁴ each independently represent a hydrogen atom or a methyl group. D and E each independently represent an alkylene group having 1 to 6 carbon atoms, n ₁ and n ₂ each independently represents an integer of 0 to 20, and n ₁ + n ₂ is 0 to 40. ]

  According to the photosensitive resin composition of the present invention, by including the component (B-1) in the component (B), the compatibility with the binder polymer can be increased, and the alkali developability can be improved. ) Component can increase the glass transition temperature (Tg) of the cured film, improve the crack resistance and HAST resistance, and improve the resolution by including the component (B-3). Moreover, by containing a polyfunctional photopolymerizable compound such as the component (B-3), a tough cured film can be formed after curing, and a solder resist with further improved crack resistance can be obtained. In addition, a good forward taper via shape can be obtained after curing. Furthermore, the solder resist obtained from the photosensitive resin composition of the present invention is hardly contaminated even under high temperature and high humidity conditions, and has excellent HAST resistance.

  Furthermore, in the photosensitive resin composition of this invention, the said (B-2) component is 10-40 mass% on the basis of the solid content whole quantity of the said (B) component, The said (B-3) component is It is preferable that it is 10-59 mass%. Thereby, alkali developability, crack resistance, HAST resistance, and via shape characteristics can be improved in a balanced manner.

In the photosensitive resin composition of the present invention, in the general formulas (1) and (2), the A, B, D, and E are each independently an ethylene group or a propylene group, and the X is the following formula (8 It is preferable that it is a divalent organic group represented by this. Thereby, the dispersibility with respect to an alkali developing solution can be improved, the glass transition temperature (Tg) of the cured film can be increased, and crack resistance and HAST resistance can be further improved.

  In the photosensitive resin composition of the present invention, the component (B-1) preferably contains 2,2-bis (4- (meth) acryloxypolyethoxy) phenyl) propane. Thereby, the dispersibility with respect to alkali developability can be improved, and alkali developability can further be improved.

Moreover, in the photosensitive resin composition of this invention, it is preferable that the said (B-2) component contains the compound represented by following General formula (3). Thereby, crack resistance and HAST resistance can further be improved.
[In Formula (3), R ⁵ and R ⁶ each independently represent a hydrogen atom or a methyl group. ]

Moreover, in the photosensitive resin composition of this invention, it is preferable that the said (B-3) component contains the compound represented by following General formula (9). Thereby, crack resistance can be further improved and a favorable via shape can be obtained.
Wherein (9), R represents a hydrogen atom or ^-CO-CR 9 = CH ^_2, showing the respective R 7 to R ⁹ independently represent a hydrogen atom or a methyl group. ]

  In the photosensitive resin composition of the present invention, the component (C) preferably contains an acyl phosphine oxide compound. As a result, the photosensitive resin composition exhibits excellent sensitivity to exposure light and good transparency to ultraviolet light, resulting in a high reaction rate at the bottom of the resist and a better via shape with a better forward taper shape. It is done.

  The component (D) preferably contains a thioxanthone compound. Since the thioxanthone-based compound absorbs ultraviolet rays on the long wavelength side, the absorption wavelength range of the photosensitive resin composition can be widened and cured more efficiently.

  In the photosensitive resin composition of the present invention, an excellent forward tapered taper good via shape can be obtained by using an acylphosphine oxide compound as the component (C) and a thioxanthone compound as the component (D). It is done.

  The present invention also provides a photosensitive element comprising a support and a layer made of the above-described photosensitive resin composition of the present invention formed on the support. 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, this invention provides the soldering resist (it is also called "photosensitive permanent resist") which consists of a photocured material of the said photosensitive resin composition of this invention formed on the board | substrate for printed wiring boards. 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 sufficient crack resistance and HAST resistance.

  Moreover, this invention provides a printed wiring board provided with the board | substrate for printed wiring boards, and the soldering resist which consists of photocured material of the said photosensitive resin composition of this invention formed on this printed wiring board board | substrate. To do. 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 sufficient crack resistance and HAST resistance. It becomes.

  According to the present invention, when a solder resist is formed on a printed wiring board, a favorable via shape can be obtained, and a photosensitive resin composition excellent in sufficient crack resistance and HAST resistance, and The used photosensitive element, solder resist, and printed wiring board can be provided.

It is a schematic sectional drawing which shows one Embodiment of the photosensitive element which concerns on this invention. (A) is a schematic cross-sectional view showing an example of a solder resist whose via shape is a “forward taper” shape, and (b) is an electron micrograph showing an example of a solder resist whose via shape is a “forward taper” shape ( Example 2, magnification: 1000 times). (A) is a schematic cross-sectional view showing an example of a solder resist whose via shape is a “straight” shape, and (b) is an electron micrograph showing an example of a solder resist whose via shape is a “straight” shape (Example) 1, magnification: 1000 times). (A) is a schematic cross-sectional view showing an example of a solder resist having a via shape of “undercut”, and (b) is an electron micrograph showing an example of a solder resist having a via shape of “undercut” ( Comparative Example 2, magnification: 1000 times). (A) is a schematic cross-sectional view showing an example of a solder resist whose via shape is an “overhang” shape, and (b) is an electron micrograph showing an example of a solder resist whose via shape is an “overhang” shape ( Comparative Example 4, magnification: 1000 times).

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Photosensitive element, 10 ... Support film, 14 ... Photosensitive layer, 2 ... Evaluation board | substrate provided with solder resist, 21 ... Solder resist, 22 ... Evaluation board | substrate (board | substrate main body), 23 ... Opening part.

  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 sensitizer. contains. Hereinafter, the components (A) to (D) will be described in detail.

(A) Binder polymer The component (A) of the present invention is not particularly limited. For example, acrylic resin, polyurethane, epoxy resin, phenoxy resin, polyester, polyamide, polyamide epoxy, polyimide, polyamideimide, polyesterimide, polycarbonate, melamine Known resins such as resins, polyphenylene sulfide, polyoxybenzoyl, polyalkyd and the like and acid-modified resins thereof may be mentioned. 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. Among them, (meth) acrylic acid alkyl ester is preferable. 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 (4) and the alkyl group of these compounds are mentioned, for example.
^{_{CH 2 = C (R 10)}} -COOR 11 (4)
Wherein ^{(4), R 10} represents a hydrogen atom or a methyl ^{group, R 11} represents an alkyl group having 1 to 12 carbon atoms. ]

As the alkyl group having 1 to 12 carbon atoms represented by R ¹¹ in the general formula (4), 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 (4) 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 preferably 30 to 150 mgKOH / g, more preferably 50 to 100 mgKOH / g, and more preferably 60 to 80 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 measuring method, the Mw of the binder polymer is preferably 5,000 to 150,000, more preferably 20,000 to 100,000, and particularly preferably 30,000 to 80,000. When Mw is less than 5000, the developer resistance tends to decrease, and when it exceeds 300,000, 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.

(B) Photopolymerizable compound having an ethylenically unsaturated bond The component (B) of the present invention is (B-1) a photopolymerizable compound represented by the following general formula (1), (B-2) the following general The photopolymerizable compound represented by Formula (2), and (B-3) a photopolymerizable compound having three or more ethylenically unsaturated bonds are contained.
[In Formula (1), R ¹ and R ² each independently represent a hydrogen atom or a methyl group. A and B each independently represent an alkylene group having 1 to 6 carbon atoms, m ₁ and m ₂ each independently represents an integer of 1 to 20, and m ₁ + m ₂ is 4 to 40. ]
[In Formula (2), X represents a divalent organic group containing an alicyclic skeleton, and R ³ and R ⁴ each independently represent a hydrogen atom or a methyl group. D and E each independently represent an alkylene group having 1 to 6 carbon atoms, n ₁ and n ₂ each independently represents an integer of 0 to 20, and n ₁ + n ₂ is 0 to 40. ]

Each component constituting the component (B) will be described. First, (B-1) In the general formula (1), A and B are each an alkylene group having 1 to 6 carbon atoms. Examples of the alkylene group having 1 to 6 carbon atoms include a methylene group, an ethylene group, a propylene group, a trimethylene group, a butylene group, an amylene group, and a hexylene group. Here, an isomeric structure exists in the butylene group, the amylene group, and the hexylene group, but what is used in the present invention is not limited to one structure. A and B are preferably ethylene groups or propylene groups, and more preferably ethylene groups from the viewpoint of improving the dispersibility of the sludge. In the general formula (1), when m ₁ or m ₂ is 2 or more, two or more adjacent A or B may be the same or different. In addition, when A or B is two or more alkylene groups, the structural unit of-(A-O)-or-(B-O)-may be present randomly or in a block form. Also good.

Further, in the general formula (1), _{m 1} or _{m 2} is an integer of 1 to _20, m 1 + _{m 2} is 4 to 40. From the viewpoint of reducing development sludge, m ₁ + m ₂ is preferably 6 to 20, and more preferably 8 to 12. When m ₁ + m ₂ is less than 4, the development time tends to be long, and when m ₁ + m ₂ exceeds 40, sufficient resolution tends not to be obtained.

  Furthermore, the photopolymerizable compound represented by the above general formula (1) which is the component (B-1) of the present invention is such that A and B in the formula (1) are only ethylene groups from the viewpoint of alkali developability. A photopolymerizable compound constituted by, for example, 2,2-bis (4-((meth) acryloxypolyethoxy) phenyl) propane polyethoxy is tetraethoxy, pentaethoxy, hexaethoxy, heptaethoxyoctaethoxy, Photopolymerizable compounds such as nonaethoxy, decaethoxy, undecaethoxy, dodecaethoxy, tridecaethoxy, tetradecaethoxy, pentadecaethoxy, hexadecaethoxy, heptadecaethoxy, octadecaethoxy, nonadecaethoxy, eicosaethoxy, etc. Can be mentioned. Of these, 2,2-bis (4- (methacryloxypentaethoxy) phenyl) propane is particularly preferable. 2,2-bis (4- (methacryloxypentaethoxy) phenyl) propane is FA-321M (manufactured by Hitachi Chemical Co., Ltd., product name) or BPE-500 (manufactured by Shin-Nakamura Chemical Co., Ltd., product name). ) Commercially available. These can be used alone or in any combination of two or more.

  Moreover, content of (B-1) component is 5-25 mass% on the basis of the solid content whole quantity of said (A) component and (B) component, and it is more preferable that it is 5-20 mass%. . If this content is less than 5% by mass, the development time tends to be long, and if it exceeds 25% by mass, the glass transition temperature (Tg) of the cured film tends to be low, and crack resistance and HAST resistance tend to decrease. is there.

Next, among the components (B), (B-2) the photopolymerizable compound represented by the general formula (2) will be described. X in the formula (2) is a divalent organic group containing an alicyclic skeleton, for example, a divalent organic containing an alicyclic skeleton represented by the following formulas (5) to (8). Groups are preferred.

Moreover, D and E in the said General formula (2) are C1-C6 alkylene groups, respectively.
Examples of the alkylene group having 1 to 6 carbon atoms include a methylene group, an ethylene group, a propylene group, a trimethylene group, a butylene group, an amylene group, and a hexylene group. Here, an isomeric structure exists in the butylene group, the amylene group, and the hexylene group, but what is used in the present invention is not limited to one structure. D and E are preferably ethylene groups or propylene groups, and more preferably ethylene groups from the viewpoint of improving the dispersibility of sludge. Further, in the general formula (2), when n ₁ or n ₂ is 2 or more, two or more A or B that adjacent may be different even in each identical. In addition, when A or B is two or more alkylene groups, the structural unit of-(A-O)-or-(B-O)-may be present randomly or in a block form. Also good.

Further, in the general formula (2), _{n 1} or _{n 2} is an integer of 0 to _20, n 1 + _{n 2} is 0 to 40. From the viewpoint of reducing development sludge, n ₁ + n ₂ is preferably 0 to 20, and more preferably 0 to 10.

The component (B-2) of the present invention is particularly preferably a photopolymerizable compound represented by the following general formula (3) from the viewpoint of increasing the glass transition temperature (Tg) of the cured film.

In formula (3), R ⁵ and R ⁶ each independently represent a hydrogen atom or a methyl group. Among the compounds represented by the general formula (3), tricyclodecane dimethanol dimethacrylate in which R ⁵ and R ⁶ are both methyl groups is NK-DCP (manufactured by Shin-Nakamura Chemical Co., Ltd., product name). ) Commercially available.

  Moreover, content of (B-2) component is 4-10 mass% on the basis of the solid content whole quantity of the said (A) component and (B) component, and it is more preferable that it is 5-10 mass%. . If this content is less than 4% by mass, the glass transition temperature (Tg) of the cured film tends to be low, and the crack resistance and HAST resistance tend to decrease. If it exceeds 10% by mass, the surface tackiness deteriorates. Tend.

  Next, among the components (B), (B-3) a photopolymerizable compound having three or more ethylenically unsaturated bonds will be described. Examples of the component (B-3) of the present invention include trimethylolpropane tri (meth) acrylate, trimethylolpropane EO-modified tri (meth) acrylate, trimethylolpropane PO-modified tri (meth) acrylate, and isocyanuric acid EO modification. Examples include tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, and dipentaerythritol hexa (meth) acrylate. These can be used alone or in combination of two or more.

The component (B-3) of the present invention is preferably a photopolymerizable compound having 5 or more ethylenically unsaturated bonds represented by the following general formula (9) from the viewpoints of resolution and via shape.

Wherein (9), R represents a hydrogen atom or ^-CO-CR 9 = CH ^_2, showing the respective R 7 to R ⁹ independently represent a hydrogen atom or a methyl group. Among the compounds represented by the general formula (9), dipentaerythritol hexaacrylate in which R is —CO—CR ⁹ ═CH ₂ and R ^{7 to} R ⁹ are hydrogen atoms is KAYARAD-DPHA (Nippon Kayaku) It is commercially available as a product name.

  Moreover, content of (B-3) component is 4-15 mass% on the basis of the solid content whole quantity of the said (A) component and (B) component, and it is more preferable that it is 7-12 mass%. . If this content is less than 4% by mass, the resolution tends to decrease and the via shape tends to deteriorate, and if it exceeds 15% by mass, the tackiness of the surface tends to deteriorate.

  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 -40 mass%, and it is especially preferable that it is 25-35 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.

  Moreover, in the photosensitive resin composition of this invention, the said (B-1) component is 5-25 mass% on the basis of the solid content whole quantity of the said (A) component and (B) component, (B- 2) It is preferable that a component is 4-10 mass% and (B-3) component is 4-15 mass%. As a result, the effects of crack resistance, HAST resistance, and good via shape can be further improved.

  Furthermore, in the photosensitive resin composition of the present invention, the component (B-2) is preferably 10 to 40% by mass based on the total solid content of the component (B), and the component (B-3). The component is 10 to 59% by mass, more preferably the component (B-2) is 15 to 40% by mass, the component (B-3) is 15 to 59% by mass, and further preferably the component ( It is preferable that B-2) component is 20-35 mass%, and the said (B-3) component is 20-55 mass%. Thereby, alkali developability, crack resistance, HAST resistance, and via shape characteristics can be improved in a balanced manner.

(C) Photopolymerization initiator As the component (C) of the present invention, for example, 4,4′-bis (diethylamine) benzophenone, benzophenone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl)- Aromatic ketones such as butanone-1,2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propanone-1, quinones such as alkylanthraquinones, benzoin compounds such as benzoin and alkylbenzoin, benzoin alkyls Benzoin ether compounds such as ether, 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) -4,5- 2,4,5 such as phenylimidazole dimer, 2- (o-methoxyphenyl) -4,5-diphenylimidazole dimer, 2- (p-methoxyphenyl) -4,5-diphenylimidazole dimer -Triarylimidazole dimer, N-phenylglycine, N-phenylglycine derivative, coumarin compounds such as 7-diethylamino-4-methylcoumarin, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide ( Ciba Specialty Chemicals Co., Ltd., product name “IRGACURE-819”), 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (Ciba Specialty Chemicals Co., Ltd., 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.) Product name “IRGACURE-OXE02”), 9-phenylacridine, 1,7-bis (9,9′-acridinyl) heptane (manufactured by Adeka Co., Ltd., product name “N-1717”) )) 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) of the present invention preferably contains an acylphosphine oxide compound from the viewpoint of obtaining a better via shape, and is represented by the bis (2,4,6) represented by the following formula (10). -Trimethylbenzoyl) -phenylphosphine oxide is particularly preferred. 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 (10), the photosensitive resin composition of the present invention is more excellent in transparency and is also 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 resist shape tends to be difficult to obtain.

(D) Sensitizer Examples of the component (D) of the present invention include pyrazoline, anthracene, coumarin, xanthone, thioxanthone, oxazole, benzoxazole, thiazole, benzothiazole, triazole, Examples include stilbene-based, triazine-based, thiophene-based, and naphthalimide-based compounds. These can be used alone or in combination of two or more.

The component (D) of the present invention 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. In particular, 2,4-diethylthioxanthone represented by the following formula (11) is preferably included. 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 (11), the photosensitive resin composition of the present invention can have higher sensitivity to exposure light.

  Moreover, content of (D) component in the photosensitive resin composition of this invention is 0.01-10 mass parts with respect to 100 mass parts of solid content whole quantity of (A) component and (B) component. Is preferable, it is more preferable that it is 0.05-5 mass parts, and it is especially preferable that it is 0.1-2 mass parts. If the content is less than 0.01 parts by mass, good sensitivity and resolution tend to be difficult to obtain, and if it exceeds 10 parts by mass, a good resist shape tends to be difficult to obtain.

  In addition, the photosensitive resin composition of this invention may contain components other than the above-mentioned (A)-(D) 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 prevention agents, 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. The amount of these components added can be about 0.01 to 20 parts by mass with respect to 100 parts by mass of the total amount of component (A) and component (B). These are used alone or in combination of two or more.

  The photosensitive resin composition of the present invention is dissolved in a solvent such as methanol, ethanol, acetone, methyl ethyl ketone, methyl cellosolve, ethyl cellosolve, toluene, N, N-dimethylformamide, propylene glycol monomethyl ether, or a mixed solvent thereof. It is good also as a solution about 30-60 mass% of solid content. 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. The photosensitive element 1 shown in FIG. 1 includes a support film 10 and a photosensitive layer 14 made of a photosensitive resin composition formed on the support film 10. You may further provide the protective film (not shown) which coat | covers.

  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 easily broken when the support film 10 is peeled off before development. If it exceeds 25 μm, the resolution tends to decrease. In addition, you may use the support film 10 by laminating | stacking on the both surfaces of the photosensitive layer 14 one as a support body of the photosensitive layer 14, and the other as a protective film of the photosensitive resin composition.

  As the protective film, for example, a polymer film having heat resistance and solvent resistance such as polyethylene terephthalate, polypropylene, polyethylene, and polyester can be used. Examples of commercially available products include, for example, product names “Alphan MA-410” and “E-200C” manufactured by Oji Paper Co., Ltd., polypropylene films manufactured by Shin-Etsu Film Co., Ltd., and product names “PS-25” manufactured by Teijin Limited. Polyethylene terephthalate film such as PS series is not limited to these. 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 preferably has a smaller adhesive strength between the photosensitive layer 14 and the protective film than the adhesive strength between the photosensitive layer 14 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 14 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 14 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, it tends to be difficult to apply industrially, and if it exceeds 100 μm, the effect of the present invention is reduced, and the adhesive force and resolution tend to be reduced.

  The photosensitive layer 14 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 with 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.

  First, 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 of the photosensitive element 1 is peeled off from the photosensitive layer 14, and the exposed surface of the photosensitive layer 14 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 14 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 removing the support film 10, the photosensitive layer 14 can be irradiated with actinic rays.

  As the active light source, a known light source such as a carbon arc lamp, a mercury vapor arc lamp, an ultrahigh pressure mercury lamp, a high pressure mercury lamp, or a xenon lamp can be used. 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 of sodium carbonate, a dilute solution of 0.1 to 5% by mass of potassium carbonate, and a dilute solution of 0.1 to 5% by mass of 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 14 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 mJ / 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).

  In addition, 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 1-6 and Comparative Examples 1-7)
(Preparation of photosensitive resin composition)
Table 1 shows the raw materials and blending composition (parts by weight) of the component (A) and other components used in the examples and comparative examples. Tables 2 and 3 show blending amounts (parts by weight) for the components (B), (C), and (D) used in Examples and Comparative Examples. Based on the compositions shown in Tables 1 to 3, photosensitive resin composition solutions were prepared.

In addition, the detail of each component in Table 2 and Table 3 is as follows.
(B) Photopolymerizable compound (B-1): 2,2-bis (4- (methacryloxypentaethoxy) phenyl) propane (manufactured by Hitachi Chemical Co., Ltd., product name “FA-321M”)
(B-2): Tricyclodecane dimethanol dimethacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., product name “NK-DCP”)
(B-3): Dipentaerythritol hexaacrylate (manufactured by Nippon Kayaku Co., Ltd., product name “KAYARAD-DPHA”)
(C) Photopolymerization initiator (C-1): bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide (manufactured by Ciba Specialty Chemicals Co., Ltd., product name “IRGACURE-819”)
(C-2): 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (product name “DAROCUR-TPO” manufactured by Ciba Specialty Chemicals Co., Ltd.)
(C-3): 1- [9-ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl] ethanone 1- (o-acetyloxime) (manufactured by Ciba Specialty Chemicals, product name) "IRGACURE-OXE02")
(C-4): 1,7-bis (9,9′-acridinyl) heptane (manufactured by Adeka, product name “N-1717”)
(D) Sensitizer (D-1): 2,4-diethylthioxanthone (manufactured by Nippon Kayaku Co., Ltd., product name “KAYACURE-DETX”)

(Production of photosensitive element)
Next, the solution of the obtained photosensitive resin composition was uniformly applied onto a 16 μm-thick polyethylene terephthalate film (manufactured by Teijin Limited, product name “HTF01”) as a support, and hot air at 80 ° C. and 125 ° C. A photosensitive layer made of a photosensitive resin composition was formed by drying with a convection 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. Then, the protective film which covers a photosensitive layer was affixed, and the photosensitive element was obtained.

(Preparation of evaluation laminate)
The copper surface of a glass cloth base epoxy resin double-sided copper-clad laminate (made by Hitachi Chemical Co., Ltd., product name “MCL-E-679” having a copper foil thickness of 18 μm and a copper foil layer on both sides) Chemical roughening was performed under the conditions of a treatment temperature of 35 ° C., a spray pressure of 0.2 MPa, and an etching amount of 2.0 μm using a No. processing machine (manufactured by Mec Co., Ltd.). On the copper surface of the obtained copper-clad laminate, the polyethylene film of the photosensitive element is peeled off, and using a press-type vacuum laminator (product name “MVLP-500” manufactured by Meiki Seisakusho) Thermocompression bonding was performed under the conditions of 70 ° C., vacuuming time 20 seconds, laminating press time 30 seconds, atmospheric pressure 4 hPa or less, and pressure bonding pressure 0.4 MPa to obtain a laminate for evaluation.

(Evaluation of photosensitive element)
The following tests were carried out using the photosensitive elements of Examples 1 to 6 and Comparative Examples 1 to 7, respectively, and the sensitivity, glass transition temperature (Tg), alkali developability, vias when each photosensitive element was used. The shape, crack resistance and HAST resistance were evaluated. The results are summarized in Table 4 and Table 5.

<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. A photo tool having a 41-step tablet is closely attached as a negative, and an EXM-1201 type exposure machine manufactured by Oak Manufacturing Co., Ltd. is used with an energy amount such that the number of remaining step steps after development of the 41-step tablet is 14. Were exposed. 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 5 ° C./min, a measurement range of 25 to 350 ° C., and a weight of 5 g.

<Alkali developability>
The laminated body for evaluation exposed under the above exposure conditions was allowed to stand at room temperature for 1 hour, and then the polyethylene terephthalate on this laminated body was peeled off, and a 1% by weight sodium carbonate aqueous solution at 30 ° C. was twice the minimum development time. Spray development was performed over time. 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. The shorter the minimum development time (MD), the better the alkali developability. When the minimum development time exceeds 70 seconds, development is impossible.

<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 development conditions, ultraviolet irradiation is performed with an energy amount of 1 J / cm ² using an ultraviolet irradiation device manufactured by Oak Manufacturing Co., Ltd., and further heat treatment is performed at 160 ° C. for 60 minutes, thereby obtaining a circular shape. An evaluation substrate having a solder resist in which an opening was formed was obtained.

  About the said board | substrate for evaluation, the shape (via shape) of the circular opening part of diameter 80micrometer formed in the soldering resist was observed using the scanning electron microscope (the Keyence company make, product name "VE-8800"). 2A is a schematic cross-sectional view showing an example of a solder resist whose via shape is “forward taper”, and FIG. 2B is an example of a solder resist whose via shape is “forward taper”. It is an electron micrograph (Example 2, magnification: 1000 times). 3A is a schematic cross-sectional view showing an example of a solder resist whose via shape is a “straight” shape, and FIG. 3B is an example of a solder resist whose via shape is a “straight” shape. It is an electron micrograph (Example 1, magnification: 1000 times). 4A is a schematic cross-sectional view showing an example of a solder resist whose via shape is an “undercut” shape, and FIG. 4B is an example of a solder resist whose via shape is an “undercut” shape. Is an electron micrograph showing Comparative Example 2 (magnification: 1000 times). 5A is a schematic cross-sectional view showing an example of a solder resist whose via shape is an “overhang” shape, and FIG. 5B is an example of a solder resist whose via shape is an “overhang” shape. Is an electron micrograph (Comparative Example 4, magnification: 1000 times). 2A to 5A, 2 is a substrate provided with a solder resist, 21 is a solder resist, 22 is an evaluation substrate, and 23 is an opening. The via shape is preferably a “forward taper” shape as shown in FIG. 2 or a “straight” shape as shown in FIG. Shape is desirable. The bottom of the resist elutes at the time of development due to underexposure, and the reverse taper shape such as “undercut” shown in FIG. 4 and the upper part of the resist protruding due to overexposure, such as “overhang” shown in FIG. When soldering, there is a possibility that the adhesiveness of the solder may deteriorate, 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 peeling degree 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.
A: No cracking or peeling of solder resist was observed B: No cracking or peeling of solder resist was observed

<HAST resistance>
First, the copper surface of a printed wiring board substrate (product name “MCL-E-679” manufactured by Hitachi Chemical Co., Ltd.) in which 18 μm thick copper foil is laminated on a glass epoxy base material is etched to obtain a line / space. Was 28 μm / 32 μm, the lines were not in contact with each other, and comb electrodes on the same surface opposed to each other were 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%/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.
A: The occurrence of migration in the solder resist could not be confirmed B: The occurrence of migration in the solder resist could be confirmed

<Desmear resistance>
A simple desmear (roughening) treatment was performed under the following treatment conditions to evaluate desmear resistance. After the desmear treatment, the cured film was visually observed for discoloration and evaluated according to the following criteria.
A: No discoloration of the cured film B: No discoloration of the cured film C: Some discoloration of the cured film D: Discoloration of the cured film observed Desmear treatment conditions Manganese Treatment (Atotech Concentrate Compact CP): 50 ° C./5 minutes Dragout treatment (pure water): 50 ° C./1 minute Neutralization treatment (Atotech Securiganth P500): 40 ° C./5 minutes Water washing: 5 minutes Baking: 80 ° C. / 30 minutes

<Gold plating resistance>
Electroless Ni / Au plating treatment was performed under the following treatment conditions to evaluate gold plating resistance. After the electroless Ni / Au plating treatment, the formation of plating and the occurrence of plating peeling on the bottom of the resist were observed with an optical microscope (manufactured by Keyence Corporation, product name “VHX-100”), and evaluated according to the following criteria.
A: Plating was formed and plating was not peeled off B: Plating was formed and plating was peeled off C: Plating was not formed Plating treatment conditions Degreasing (Sulcup ACL-007): 50 ° C. / 5 minutes Washing with water Soft etch (sulfuric acid + SPS): 25 ° C./2 minutes Washing with water Pre-dip (5 vol% sulfuric acid): 25 ° C./3 minutes Activation (KAT-450): 25 ° C./90 seconds Washing with water Electroless Ni plating ( NPR-4 manufactured by Uemura Kogyo Co., Ltd .: 80 ° C./15 min. Replacement Au plating (TAM-55 manufactured by Uemura Kogyo Co., Ltd.): 85 ° C./15 min.

  As shown in Table 4, Examples 1 to 6 were sufficiently excellent in via shape, crack resistance and HAST resistance. Furthermore, Examples 4 to 6 were sufficiently excellent in desmear resistance and gold plating resistance. On the other hand, the contents of the components (B-1), (B-2) and (B-3) contained in the photopolymerizable compound of the component (B) are not within the range shown in the present invention. Comparative Examples 1 to 7 were inferior to Examples in at least two characteristics of via shape, crack resistance and HAST resistance.

  That is, according to the photosensitive resin composition of the present embodiment, a good via shape can be obtained, and a solder resist excellent in sufficient crack resistance and HAST resistance can be obtained.

Claims (9)

(A) a binder polymer;
(B) a photopolymerizable compound having an ethylenically unsaturated bond;
(C) a photopolymerization initiator;
(D) a sensitizer,
And the component (B) is
(B-1) a photopolymerizable compound represented by the following general formula (1);
(B-2) a photopolymerizable compound represented by the following general formula (2);
(B-3) a photopolymerizable compound having three or more ethylenically unsaturated bonds;
Contain,
The component (B-2) contains a compound represented by the following general formula (3),
Based on the total solid content of the component (A) and the component (B), the content of the component (B-1) is 5 to 25% by mass, and the content of the component (B-2) is 4 The photosensitive resin composition which is 10 mass% and whose content of the said (B-3) component is 4-15 mass% .
[In Formula (1), R ¹ and R ² each independently represent a hydrogen atom or a methyl group. A and B each independently represent an alkylene group having 1 to 6 carbon atoms, m ₁ and m ₂ each independently represents an integer of 1 to 20, and m ₁ + m ₂ is 4 to 40. ]
[In Formula (2), X represents a divalent organic group containing an alicyclic skeleton, and R ³ and R ⁴ each independently represent a hydrogen atom or a methyl group. D and E each independently represent an alkylene group having 1 to 6 carbon atoms, n ₁ and n ₂ each independently represents an integer of 0 to 20, and n ₁ + n ₂ is 0 to 40. ]
[In Formula (3), R ⁵ and R ⁶ each independently represent a hydrogen atom or a methyl group. ] The photosensitive resin composition according to claim 1, wherein A, B, D, and E are each independently an ethylene group or a propylene group, and X is a divalent organic group represented by the following formula (8). object.
The photosensitive resin composition of Claim 1 or 2 in which the said (B-1) component contains 2 , 2 -bis (4- (meth) acryloxy polyethoxy) phenyl) propane. The photosensitive resin composition as described in any one of Claims 1-3 in which the said (B-3) component contains the compound represented by following General formula (9).
Wherein (9), R represents a hydrogen atom or ^-CO-CR 9 = CH ^_2, showing the respective R 7 to R ⁹ independently represent a hydrogen atom or a methyl group. ] The photosensitive resin composition as described in any one of Claims 1-4 in which the said (C) component contains an acyl phosphine oxide type compound. The photosensitive resin composition as described in any one of Claims 1-5 in which the said (D) component contains a thioxanthone type compound. A photosensitive element provided with a support body and the layer which consists of a photosensitive resin composition as described in any one of Claims 1-6 formed on this support body. The solder resist which consists of a photocured material of the photosensitive resin composition as described in any one of Claims 1-6 formed on the board | substrate for printed wiring boards. A substrate for a printed wiring board, the printed and the solder resist made of a photocured product of the photosensitive resin composition according to any one of the wiring board according to claim 1 to 6 formed on a substrate, a printed circuit comprising Board.