TWI417662B - A photosensitive resin composition and a hardened product thereof - Google Patents

Description

Photosensitive resin composition and cured product thereof

The present invention relates to a photosensitive resin composition which is suitable for a thin printed circuit board which requires low warpage, in particular, a solder resist or a resin insulating layer of a flexible circuit board, and a hardened material and a hardened film. Printed circuit board.

Conventionally, a flexible circuit board uses an insulating film coated with an adhesive on a polyimide film called a cover layer, which is punched and laminated by a press, and then pressed by a press. The film is thermally cured to form a coating layer on the surface of the flexible substrate on which the circuit is formed. Since the cover layer is composed of a polyimide film as a base and a low shrinkage thermosetting resin as an adhesive layer, warpage after lamination and hardening of the press is very small, and reinforcement thereafter. The warpage of the board after sticking, heat hardening or reflow soldering of the component mounting may be very small, and it is used in a large amount for flexible substrate applications.

However, since the punching process is performed by the press, the microfabrication is difficult, and when it is laminated with the circuit board on which the circuit is formed, there is a disadvantage that the positioning accuracy is poor.

In the above, an alkali-developing photosensitive resin composition which is a photosensitive coating layer, or a dry film thereof, is proposed, and a photosensitive resin composition is proposed in the patent document 1 (JP-A-2000-131836). It contains (a) a compound having two or more hydroxyl groups and one or more carboxyl groups, (b) a bifunctional or higher polyisocyanate having a 6-membered ring structure, and (c) a (meth) acrylate having a hydroxyl group. Further, a urethane acrylate having a carboxyl group, a photopolymerization initiator, a diluent, and a bifunctional or higher epoxy resin are obtained.

However, due to the photocurable thermosetting composition, there is a problem of hardening shrinkage due to crosslinking, and warpage occurs after photocuring and after thermal curing.

In addition, a photosensitive resin composition for a solder resist of a circuit board, which contains an amine group containing a carboxyl group, is proposed in the patent document 2 (Japanese Unexamined Patent Publication No. 2005-10318). An active energy ray-curable resin of ethyl acrylate-modified epoxy (meth) acrylate, an active energy ray-curable unsaturated compound having one to two ethylenic unsaturated bonds in one molecule, a photopolymerization initiator, A thinner and a thermosetting epoxy compound, and a photosensitive resin composition containing an alkali aqueous solution soluble urethane resin, a photopolymerization initiator, and reactive crosslinking are proposed in Patent Document 3 (WO2004/079452). Agent. In addition, a photosensitive composition containing a urethane (meth) acrylate compound having a carboxyl group and having an ethylenicity other than the above is proposed in the patent document 4 (JP-A-2002-229201). A photocurable component of a saturated group compound, a thermosetting resin, a photopolymerization initiator, and a thermal polymerization catalyst.

Although the warpage after hardening of these compositions is a sufficiently small value, when it is actually used for a flexible wiring board, there is a disadvantage that warpage occurs due to heating after the reinforcing plate bonding step and heating at the time of component mounting.

Further, in recent years, laser direct exposure for the purpose of improving the positioning accuracy has been attracting attention. However, when the photosensitive resin composition as described above is used, there is a problem that a large amount of exposure and exposure time are required.

[Patent Document 1] JP-A-2000-131836 (Scope of Invention Application)

[Patent Document 2] JP-A-2005-10318 (Scope of Invention Application)

[Patent Document 3] WO 2004/079452 (Scope of Invention Patent Application)

[Patent Document 4] JP-A-2002-229201 (Scope of Invention Application)

The present invention has been made in order to eliminate the problems of the prior art as described above, and its main object is to provide an occurrence of warpage caused by heating in the manufacturing step of the flexible substrate and the subsequent step or part mounting step, and Even if the photopolymerization initiator is added in a small amount, it is highly sensitive, and it can be directly exposed by laser, and can form the same adhesion to various substrates, solder heat resistance, moisture resistance, and chemical resistance as in the conventional solder resist composition. A photosensitive resin composition of a pattern of a cured film having excellent properties such as properties and electrical insulating properties.

In addition, it is an object of the present invention to provide a printed circuit board obtained by using such a photosensitive resin composition and having a cured product having excellent properties as described above, and a cured film obtained by forming a solder resist or the like from the cured product. Printed circuit board.

In order to achieve the above object, the present invention provides a photosensitive resin composition comprising (A) a carboxyl group-containing resin and (B) an oxime ester light having a group represented by the following formula (I). A composition which can be developed by a dilute alkali aqueous solution of a polymerization initiator and a compound having two or more ethylenically unsaturated groups in the molecule (C), for 100 parts by mass of the above carboxyl group-containing resin (A) , the above oxime ester photopolymerization initiator (B) is contained in a ratio of 0.1 to 1.5 parts by mass;

(wherein R ¹ represents a hydrogen atom, a phenyl group (which may be substituted by an alkyl group having 1 to 6 carbon atoms, a phenyl group or a halogen atom), or an alkyl group having 1 to 20 carbon atoms (which may be one or more hydroxyl groups) Substituting, there may be one or more oxygen atoms in the middle of the alkyl chain), a cycloalkyl group having 5 to 8 carbon atoms, an alkanoyl group having 2 to 20 carbon atoms or a benzhydryl group (a carbon number of 1 to 6) Alkyl or phenyl substituted), R ² represents a phenyl group (which may be substituted by an alkyl group having 1 to 6 carbon atoms, a phenyl group or a halogen atom), and an alkyl group having 1 to 20 carbon atoms (more than one or more) Substituted by a hydroxyl group, may have one or more oxygen atoms in the middle of the alkyl chain), a cycloalkyl group having 5 to 8 carbon atoms, an alkanoyl group having 2 to 20 carbon atoms, or a benzhydryl group (carbon number per pass) 1~6 alkyl or phenyl substituted)).

In a preferred aspect, the carboxyl group-containing resin (A) has a structure of bisphenol A, bisphenol F, biphenyl, dimethicone skeleton or a hydrogenated skeleton thereof from the viewpoint of low warpage. Resin, or a resin having a urethane configuration. Moreover, it is preferable that the carboxyl group-containing resin (A) is a photosensitive resin having two or more radical polymerizable unsaturated double bonds, from the viewpoint of photocurability. Further, the dry coating film of the photosensitive resin composition had an absorbance at 355 nm in a range of 0.3 to 1.2 in terms of a dry film thickness of 25 μm. In addition, the photosensitive resin composition of the present invention preferably contains a thermosetting component (D) from the viewpoint of improving properties such as heat resistance of the cured film.

The photosensitive resin composition may be either a liquid form or a dry film form.

Furthermore, the present invention provides a printed circuit board having a cured product obtained by photohardening the photosensitive resin composition or a dry film thereof on copper, in particular, hardening by laser hardening of a laser source. And hardening the film by hardening the light by laser light having a maximum wavelength of 350 to 410 nm, and hardening the film.

The photosensitive resin composition of the present invention contains the oxime ester-based photopolymerization initiator (B) having a group represented by the following formula (I) as having two or more of the carboxyl group-containing resin (A) and the molecule. The photopolymerization initiator in which the ethylenically unsaturated group-containing compound (C) is blended together can suppress the occurrence of warpage caused by heating in the manufacturing step of the flexible substrate and the subsequent step or part mounting step, and even The above-mentioned oxime ester-based photopolymerization initiator (B) is contained in a small amount in an amount of 0.1 to 1.5 parts by mass based on 100 parts by mass of the carboxyl group-containing resin (A), and is also highly sensitive or directly exposed by laser. Further, the photosensitive resin composition of the present invention is a composition which can be developed by a dilute aqueous alkali solution, and has low warpage properties, and can form the same adhesion to various substrates as the conventional solder resist composition. A pattern of a hardened film excellent in properties such as solder heat resistance, moisture resistance, chemical resistance, electroless gold plating resistance, and electrical insulating properties. Therefore, the photosensitive resin composition of the present invention can be favorably applied to the formation of a hardened film such as a solder resist or a resin insulating layer of a printed circuit board, particularly a flexible printed circuit board.

Best form for implementing the invention

The present inventors have found that the post-heating step and the warpage at the time of component mounting are caused by the volatilization of the photopolymerization initiator, and the absorbance of the composition greatly affects the warpage. The present inventors have further studied the above phenomenon, and as a result, it has been found that an oxime ester-based photopolymerization initiator (B) having a group represented by the following formula (I) is used as a carboxyl group-containing resin (A) and in a molecule. When a photopolymerization initiator containing a compound (C) having two or more ethylenically unsaturated groups is blended together, a photosensitive resin composition which has sufficient light characteristics even when added in a small amount and which can be directly exposed by laser can be obtained. The invention has finally been completed.

Each component of the photosensitive resin composition of the present invention will be described below.

First, as the carboxyl group-containing resin (A), any of a carboxyl group-containing resin having no ethylenic unsaturated double bond or a photosensitive carboxyl group-containing resin having an ethylenically unsaturated double bond can be used, but no Specific compounds, particularly exemplified below (which may be either an oligomer or a polymer) may be suitably used.

(1) copolymerizing an unsaturated carboxylic acid such as (meth)acrylic acid with a compound having an unsaturated double bond such as styrene, α-methylstyrene, a lower alkyl (meth)acrylate or isobutylene. a carboxyl group-containing resin.

(2) a diisocyanate such as an aliphatic diisocyanate, a branched aliphatic diisocyanate, an alicyclic diisocyanate or an aromatic diisocyanate, or a carboxyl group containing dimethylolpropionic acid or dimethylolbutanoic acid a diol compound, a polycarbonate-based polyol, a polyether-based polyol, a polyester-based polyol, a polyolefin-based polyol, an acrylic polyol, a bisphenol A-based alkylene oxide adduct diol, and a phenol A carboxyl group-containing urethane resin obtained by a polyaddition reaction of a diol compound such as a hydroxyl group or an alcoholic hydroxyl group.

(3) From diisocyanate and bisphenol A epoxy resin, hydrogenated bisphenol A epoxy resin, brominated bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin, (meth) acrylate of a bifunctional epoxy resin such as a bixylenol type epoxy resin or a bisphenol type epoxy resin, or a partial acid anhydride modified product thereof, a carboxyl group-containing compound, and a diol compound A photosensitive carboxyl group-containing urethane resin obtained by the reaction.

(4) In the synthesis of the resin of the above (2) or (3), a molecule having a hydroxyalkyl (meth) acrylate or the like has one hydroxyl group and one or more (meth) acrylonitrile groups. a compound, and a terminal (meth) acrylated carboxyl group-containing urethane resin.

(5) In the synthesis of the resin of the above (2) or (3), one or more isocyanate groups and one or more molecules are added to the molecule such as isophorone diisocyanate and pentaerythritol triacrylate. A (meth)acrylonitrile-based compound and a terminal (meth)acrylated carboxyl group-containing urethane resin.

(6) A photosensitive carboxyl group-containing resin obtained by reacting a polyfunctional (solid) epoxy resin as described later with (meth)acrylic acid and adding a dibasic acid anhydride to the produced hydroxyl group.

(7) A photosensitive epoxy resin obtained by reacting a polyfunctional epoxy resin which further epoxidizes a hydroxyl group of a bifunctional (solid) epoxy resin with epichlorohydrin with (meth)acrylic acid, and adding a dibasic acid anhydride to the generated hydroxyl group A resin containing a carboxyl group.

(8) A polyester resin containing a carboxyl group obtained by reacting a bifunctional oxetane resin as described later with a dicarboxylic acid to form a dibasic acid anhydride in the produced first-order hydroxyl group.

(9) A photosensitive carboxyl group-containing resin obtained by adding a compound having one epoxy group and one or more (meth) acrylonitrile groups in one molecule to the above resins (1) to (8).

Among these carboxyl group-containing resins, a compound having an isocyanate group (including a diisocyanate) used in the synthesis of the resin of the above (2) to (5) is preferably a diisocyanate having no benzene ring. In the case, the polyfunctional and bifunctional epoxy resin used in the synthesis of the resin of the above (6) and (7) has a linear form of a bisphenol A skeleton, a bisphenol F skeleton, a biphenyl skeleton, and a bixylenol skeleton. In the case of constructing a compound and a hydrogenated compound thereof, it is preferred from the viewpoint of flexibility and the like. On the other hand, the resins of the above (2) to (5) and the modified product of the above (9) are preferably bonded to the main chain with a urethane bond. In addition, the resin other than the above (1), (2), and (8) is preferred from the viewpoint of photocurability because it has a photosensitive group (radical polymerizable unsaturated double bond) in the molecule.

Further, in the present specification, the (meth) acrylate is a term generally referred to as an acrylate, a methacrylate, and a mixture thereof, and the other similar expressions are also the same.

The carboxyl group-containing resin (A) as described above, due to the backbone. The side chain of the polymer has a large number of free carboxyl groups and can be visualized by a dilute aqueous alkali solution.

Further, the acid value of the carboxyl group-containing resin (A) is preferably in the range of 40 to 200 mgKOH/g, more preferably 45 to 120 mgKOH/g. When the acid value of the carboxyl group-containing resin (A) is less than 40 mgKOH/g, alkali development becomes difficult. On the other hand, if it exceeds 200 mgKOH/g, the exposed portion is dissolved by the developing solution, and the wire system exceeds the desired position. The thickness is reduced or, as the case may be, the exposure portion is not different from the final exposure portion, and is dissolved and peeled off by the developing liquid, and it is difficult to form a normal resist pattern.

In addition, although the weight average molecular weight of the carboxyl group-containing resin (A) varies depending on the resin skeleton, it is generally preferably in the range of 2,000 to 150,000, more preferably in the range of 5,000 to 100,000. When the weight average molecular weight is less than 2,000, the adhesiveness of the coating film is poor, and the moisture resistance of the coating film after exposure is poor, and film thinning occurs at the time of development, and the resolution is greatly deteriorated. On the other hand, if the weight average molecular weight exceeds 150,000, the developability is remarkably deteriorated, and the storage stability is deteriorated.

The amount of the carboxyl group-containing resin (A) is preferably in the range of 20 to 60% by mass, preferably 30 to 50% by mass based on the entire composition. If it is less than the above range, the film strength is lowered, which is not preferable. On the other hand, when it is more than the above range, the viscosity of the composition becomes high, and the coatability and the like are lowered.

In addition, the oxime ester-based photopolymerization initiator (B) having the group represented by the above formula (I) used in the present invention has sufficient sensitivity even in a small amount, and can effectively prevent post-heating and initiator volatilization during component mounting. The resulting warpage. In the photosensitive composition for the photosensitive coating layer and the solder resist, the photopolymerization initiator is contained in an amount of 5 to 20 parts by mass based on 100 parts by mass of the carboxyl group-containing resin. However, for 100 parts by mass of the carboxyl group-containing resin (A), 0.1 to 1.5 parts by mass of the oxime ester-based photopolymerization initiator (B) having the group represented by the above formula (I) is sufficient, and Give the hardened material with less warpage after the parts are installed. It is considered that in the case of a composition containing a plurality of photopolymerization initiators, the photopolymerization initiator may volatilize and shrink in volume upon post-heating or reflow soldering of component mounting, resulting in occurrence of warpage. On the other hand, in the case of thermal curing of the composition, if it is a photopolymerization initiator which is almost volatilized, there is no problem even if it is added in a relatively large amount. That is, the manufacturing process of the flexible substrate is photo-curing→thermal curing→post-heating→part mounting (reflow soldering). If a general example is given, the temperature is tempered by photohardening (at 20 to 30 ° C for several seconds) → thermosetting (At 140~160°C for 30~60 minutes) → After heating (at 150~170°C for 2 hours) → Parts installation (240~260°C for several seconds~ tens of seconds). Here, the photopolymerization initiator which is almost volatilized at the time of thermal curing is hardly left in the component which has volatilized after the hardening, and does not cause volume shrinkage during post-heating and component mounting. As such a photopolymerization initiator, a compound which is reduced by 50% or more by heating at 150 ° C is mentioned, and (B1a) which is mentioned later is suitable.

The oxime ester-based photopolymerization initiator (B) having a group represented by the above formula (I) is preferably 2-(ethyloxyiminomethyl) represented by the following formula (V). A thioxan-9-one or a compound represented by the following formulas (VI) and (VII).

(In the formula, R ¹⁰ represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, a cyclopentyl group, a cyclohexyl group, a phenyl group, a benzyl group, a benzamyl group, an alkanoyl group having 2 to 12 carbon atoms, The alkoxycarbonyl group having 2 to 12 carbon atoms (when the number of carbon atoms of the alkyl group constituting the alkoxy group is 2 or more, the alkyl group may be substituted by one or more hydroxyl groups, and one or more of the alkyl chains may be present in the middle of the alkyl chain. Oxygen atom) or phenoxycarbonyl,

R ¹¹ and R ¹³ each independently represent a phenyl group (which may be substituted by an alkyl group having 1 to 6 carbon atoms, a phenyl group or a halogen atom) or an alkyl group having 1 to 20 carbon atoms (which may be substituted by one or more hydroxyl groups). , may have one or more oxygen atoms in the middle of the alkyl chain), a cycloalkyl group having 5 to 8 carbon atoms, an alkanoyl group having 2 to 20 carbon atoms, or a benzamidine group (a carbon number of 1 to 6) Alky or phenyl substituted),

R ¹² represents a hydrogen atom, a phenyl group (which may be substituted by an alkyl group having 1 to 6 carbon atoms, a phenyl group or a halogen atom), or an alkyl group having 1 to 20 carbon atoms (which may be substituted by one or more hydroxyl groups). There may be one or more oxygen atoms in the middle of the base chain, a cycloalkyl group having 5 to 8 carbon atoms, an alkanoyl group having 2 to 20 carbon atoms or a benzhydryl group (a group having 1 to 6 carbon atoms or Substituted by phenyl)).

[Chemical 4]

(wherein R ¹⁴ and R ¹⁵ each independently represent an alkyl group having 1 to 12 carbon atoms, M represents S, O or NH, and R ¹⁶ , R ¹⁷ , R ¹⁸ , R ¹⁹ and R ²⁰ each independently represent a hydrogen atom. Or an alkyl group having 1 to 6 carbon atoms, and m and n represent an integer of 0 to 5).

Among the above oxime ester-based photopolymerization initiators (B), more preferably 2-(ethyloxyiminomethyl)thioxanthene-9-one represented by the above formula (V) and formula (VI) The compound shown. As a commercial product, CGI-325, Irgacure OXE01, Irgacure OXEO2, etc. manufactured by Ciba Specialty Chemicals Co., Ltd.

The oxime ester-based photopolymerization initiators may be used singly or in combination of two or more.

As described above, the most suitable amount of the above-mentioned oxime ester-based photopolymerization initiator (B) is sufficient for 0.1 to 1.5 parts by mass of 100 parts by mass of the carboxyl group-containing resin (A), but in order to cause light reaction More specifically, a photopolymerization initiator (B1) or a photoretention aid (B2) other than the above oxime ester type may be added. For the purpose of reducing the warpage caused by the post-heating, the amount of the other initiator to be added is preferably 6 parts by mass or less, more preferably 100 parts by mass of the carboxyl group-containing resin (A). It is 5 parts by mass or less. Further, as an exception, the photopolymerization initiator (B1a) volatilized by the heat hardening step (heating at about 150 ° C) is more than the above range, and does not affect volatilization during the post-heating step, and can achieve the purpose. Low warpage. Such a heated volatile photopolymerization initiator (B1a) can be selected by simple analysis by thermogravimetric analysis and headspace GC-MS, etc., and the amount of volatilized photopolymerization initiator is extreme after heat hardening at 150 °C. (50% or more) varying compounds are suitable. Specific examples are 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinoacetone-1, and commercially available products include Irgacure 907 manufactured by Ciba Specialty Chemicals Co., Ltd., and the like.

Further, as a photopolymerization initiator which is not volatile at 150 ° C and can be added in a small amount, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one is exemplified. , 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone, N,N- Dimethylamino acetophenone and the like. As a commercial item, Irgacure 369, Irgacure 379, etc. by Ciba Specialty Chemicals Co., Ltd. are mentioned.

Further, examples of the mercaptophosphine oxide-based initiator include 2,4,6-trimethylbenzimidyldiphenylphosphine oxide and bis(2,4,6-trimethylbenzylidene). )-Phenylphosphine oxide, bis(2,6-dimethoxybenzylidene)-2,4,4-trimethyl-pentylphosphine oxide, and the like. As a commercial item, Lucirin TPO by BASF Corporation, Irgacure 819 by Ciba Specialty Chemicals Co., Ltd., etc. are mentioned.

In addition, examples of the photoinitiation aid and the sensitizer which can be used in the photosensitive resin composition of the present invention include a benzoin compound, an acetophenone compound, an anthraquinone compound, a thioxanthone compound, and a ketal compound. A benzophenone compound, a xanthone compound, and a tertiary amine compound.

Specific examples of the benzoin compound include benzoin, benzoin methyl ether, benzoin ethyl ether, and benzoin isopropyl ether.

Specific examples of the acetophenone compound are, for example, acetophenone, 2,2-dimethoxy-2-phenylacetophenone, and 2,2-diethoxy-2-phenylacetophenone. 1,1-dichloroacetophenone.

Specific examples of the hydrazine compound include 2-methyl hydrazine, 2-ethyl hydrazine, 2-tert-butyl fluorene, and 1-chloroindole.

Specific examples of the thioxanthone compound are, for example, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, 2,4-diisopropyl Thiophenone.

Specific examples of the ketal compound include acetophenone dimethyl ketal and benzyl dimethyl ketal.

Specific examples of the benzophenone compound include benzophenone, 4-benzylidene diphenyl sulfide, 4-benzylidene-4'-methyldiphenyl sulfide, and 4 - benzylidene-4'-ethyldiphenyl sulfide, 4-benzylidene-4'-propyldiphenyl sulfide.

Specific examples of the tertiary amine compound include, for example, an ethanolamine compound and a compound having a dialkylaminobenzene structure, such as 4,4'-dimethylaminobenzophenone (Nisocure MABP manufactured by Nippon Soda Co., Ltd.), 4, 4 Dialkylaminobenzophenone, 7-(diethylamino)-4-methyl-2H-1-benzopyridine, such as '-diethylaminobenzophenone (EAB, manufactured by Hodogaya Chemical Co., Ltd.) a dialkylamine-containing coumarin compound, 4-dimethylaminobenzoic acid ethyl ester, such as nal-2-one (7-(diethylamino)-4-methylcoumarin) Kayacure EPA), ethyl 2-dimethylaminobenzoate (Quantacure DMB manufactured by International Biosynthetic Co., Ltd.), 4-dimethylaminobenzoic acid (n-butoxy)ethyl (Quantacure BEA manufactured by International Biosynthetic Co., Ltd.), p-Isoamylethyl dimethylaminobenzoate (Kayacure DMBI, manufactured by Nippon Kayaku Co., Ltd.), 2-ethylhexyl 4-dimethylaminobenzoate (Esolol 507, manufactured by Van Dyk Co., Ltd.), 4, 4' -Diethylaminobenzophenone (EAB manufactured by Hodogaya Chemical Co., Ltd.).

Among the above photopolymerization initiators, a thioxanthone compound and a tertiary amine compound are preferred. In the photosensitive resin composition of the present invention, from the viewpoint of deep hardenability, it is preferred to contain a thioxanthone compound, of which 2,4-dimethylthioxanthone and 2,4-di are preferred. A thioxanthone compound such as ethyl thioxanthone, 2-chlorothioxanthone or 2,4-diisopropylthioxanthone.

The amount of the thioxanthone compound to be added is preferably 2 parts by mass or less, more preferably 1 part by mass or less, per 100 parts by mass of the carboxyl group-containing resin (A). When the amount of the thioxanthone compound is too large, it causes a warpage at the time of post-heating, and it is not preferable in connection with an increase in the cost of the product.

As the tertiary amine compound, a compound having a dialkylaminobenzene structure is preferred, and a dialkylaminobenzophenone compound and a dialkylamine-containing coumarin having a maximum absorption wavelength of 350 to 410 nm are particularly preferred. Compound. As the dialkylaminobenzophenone compound, the 4,4'-diethylaminobenzophenone is also low in toxicity and is preferable. The coumarin compound having a dialkylamine group having a maximum absorption wavelength of 350 to 410 nm has a small absorption wavelength in the ultraviolet region, so that the coloring is small, and it is not necessary to use a colorless and transparent photosensitive resin composition, and a coloring pigment can also be used to provide a reflection. A colored solder resist film of the coloring pigment itself. Particularly preferred is 7-(diethylamino)-4-methyl-2H-1-benzopyran-2-one because it exhibits an excellent sensitizing effect on laser light having a wavelength of 400 to 410 nm.

The amount of the tertiary amine compound to be added is preferably 0.1 to 2 parts by mass, more preferably 0.1 to 1 part by mass, per 100 parts by mass of the carboxyl group-containing resin (A). When the amount of the tertiary amine compound is 0.1 part by mass or less, a sufficient sensitizing effect may not be obtained. When it exceeds 2 parts by mass, it causes a warpage at the time of post-heating, and it is unsuitable because it is related to the cost increase of a product.

The photopolymerization initiator, the photoinitiation aid, and the sensitizer described above may be used singly or as a mixture of two or more types.

The mixing ratio of the photopolymerization initiator and the initiator auxiliary agent is not particularly limited to 100 parts by mass of the carboxyl group-containing resin (A), and the compounding ratio of 0.1 to 1.5 parts by mass is defined by the above formula (I). The base-based ester-based photopolymerization initiator (B) is preferably a dry coating film of a composition containing a coloring agent and a sensitizer described later at an absorbance at 355 nm of 0.3 to 1.2 in a dry film thickness of 25 μm. The proportion of the range is added. This range of absorbance is effective for the purpose of the present invention to reduce warpage during post-heating and reflow soldering of component mounting. Although the details are not clear, it is considered that the photoreaction of the composition is relatively uniform in the surface layer and the deep portion. When the absorbance is higher than 1.2, the light cannot be transmitted to the deep portion, and the unreacted photohardenable component remains a lot, and the violent reaction occurs due to post-heating or reflow soldering of the component mounting, and the substrate is warped or bent. On the other hand, if the absorbance is lower than 0.3, the light cannot be effectively used, and it is not suitable for laser direct exposure which is high sensitivity or one of the objects of the present invention. Further, by adjusting the absorbance to the above-mentioned appropriate range, the chemical resistance of the hardened film and the electroless gold plating property are remarkably improved. Since these phenomena are not understood in the past, they are the effects first discovered by the inventors.

As the compound (C) having two or more ethylenically unsaturated groups in the molecule, various conventionally known (meth) acrylate monomers can be used, and are not limited to those specific.

Specific examples thereof include diacrylates of diols such as ethylene glycol, methoxytetraethylene glycol, polyethylene glycol, and propylene glycol; hexanediol, trimethylolpropane, pentaerythritol, and dipentaerythritol; a polyvalent acrylate such as a polyol such as trihydroxyethyl isocyanurate or such an ethylene oxide adduct, a propylene oxide adduct or a caprolactone adduct; or a phenoxy group; a polyvalent acrylate such as an acrylate, a bisphenol A diacrylate, or an oxirane adduct of such a phenol or a propylene oxide adduct; or a urethane acrylate of the above polyol a polyvalent acrylate of a glycidyl ether such as glycerol diglycidyl ether, glycerol triglycidyl ether, trimethylolpropane triglycidyl ether or triglycidyl isocyanurate; melamine acrylate And each methacrylate corresponding to the above acrylate.

Further, an epoxy acrylate resin obtained by reacting a polyfunctional epoxy resin such as a cresol novolac type epoxy resin with (meth)acrylic acid, or a hydroxyl group of the epoxy acrylate resin may be used. An epoxy urethane acrylate compound obtained by reacting a hydroxy ester of (meth) acrylate such as pentaerythritol triacrylate or a diisocyanate compound of a diisocyanate such as isophorone diisocyanate. These epoxy acrylate-based resins can improve the photocurability without reducing the dryness of the touch.

Among the compounds containing an ethylenically unsaturated group, those having two ethylenically unsaturated groups and having a polyfunctional group and modified with ethylene oxide, propylene oxide or caprolactone are preferred. (Meth) acrylates.

Further, from the viewpoint of flame retardancy, it is preferably a 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and a conventionally known polyfunctional (meth) acrylate Michael Plus. A modified modification.

The compounding amount of the compound (C) having two or more ethylenically unsaturated groups in the molecule is preferably from 5 to 100 parts by mass, more preferably 100 parts by mass of the carboxyl group-containing resin (A). It is a ratio of 1 to 70 parts by mass. When the amount is less than 5 parts by mass, the photocurability is lowered, and it is difficult to form a pattern by the alkali developing system after the irradiation of the active energy ray, which is not preferable. On the other hand, when it exceeds 100 parts by mass, the solubility in the aqueous alkali solution is lowered, and the coating film becomes brittle, which is not preferable.

In the photosensitive resin composition of the present invention, a thermosetting component (D) may be added in order to impart heat resistance. A particularly preferred thermosetting component (D) is a thermosetting resin having two or more cyclic ether groups and/or cyclic thioether groups (hereinafter referred to as cyclic (thio)ether groups). Among these, a bifunctional epoxy resin is preferable, and a diisocyanate or a bifunctional block isocyanate can also be used.

The thermosetting component (D) having two or more cyclic (thio)ether groups in the molecule, such as a cyclic ether group or a cyclic thioether having two or more 3, 4 or 5 membered rings in the molecule. Examples of the compound of any one or two types of the group include a compound having at least two or more epoxy groups in the molecule, that is, a polyfunctional epoxy compound (D-1) having at least two or more molecules. The compound of the oxetane group, that is, the polyfunctional oxetane compound (D-2), a compound having two or more thioether groups in the molecule, that is, an episulfide resin (D-3).

Examples of the polyfunctional epoxy compound (D-1) include JER828, JER834, JER1001, and JER1004 manufactured by Nippon Epoxy Co., Ltd., Epiclon 840, Epiclon 850, Epiclon 1050, and Epiclon manufactured by Dainippon Ink and Chemicals. 2055, Epotohto YD-011, YD-013, YD-127, YD-128 manufactured by Dongdu Chemical Co., Ltd., DER317, DER331, DER661, DER664 manufactured by Ceramic Chemical Co., Ltd., Araldite of Ciba Specialty Chemicals Co., Ltd. 6071, Araldite 6084, Araldite GY250, Araldite GY260, Sumitepoxy ESA-011, ESA-014, ELA-115, ELA-128, manufactured by Sumitomo Chemical Industries, AER330, AER331, AER661, AER664 manufactured by Asahi Kasei Kogyo Co., Ltd. Bisphenol A type epoxy resin (both trade names); YL903 manufactured by Japan Epoxy Resin Co., Ltd., Epiclon 152, Epiclon 165 manufactured by Dainippon Ink and Chemicals Co., Ltd., Epotohto YDB-400, YDB- manufactured by Dongdu Chemical Co., Ltd. 500, DER542 manufactured by Ceramic Chemical Co., Ltd., Araldite 8011 manufactured by Ciba Specialty Chemicals Co., Ltd., Sumiepoxy ESBM400 manufactured by Sumitomo Chemical Industries Co., Ltd., ESB-700, AER711 manufactured by Asahi Kasei Industrial Co., Ltd. Brominated epoxy resin such as AER714 (both trade names); JER152 and JER154 manufactured by Nippon Epoxy Co., Ltd., DEN431 and DEN438 manufactured by Ceramic Chemical Co., Ltd., and Epiclon N-730 manufactured by Dainippon Ink Chemical Industry Co., Ltd. Epiclon N-770, Epiclon N-865, Epotohto YDCN-701, YDCN-704, manufactured by Dongdu Chemical Co., Ltd., Araldite ECN1235, Araldite ECN1273, Araldite ECN1299, Araldite XPY307, manufactured by Nippon Kayaku Co., Ltd. EPPN-201, EOCN-1025, EOCN-1020, EOCN-104S, RE-306, Sumiepoxy ESCN-195X, ESCN-220, manufactured by Sumitomo Chemical Industries, AERECN-235, ECN-299, etc., manufactured by Asahi Kasei Kogyo Co., Ltd. (all brand name) novolac type epoxy resin; Epiclon 830 manufactured by Dainippon Ink Chemical Industry Co., Ltd., JER807 manufactured by Nippon Epoxy Co., Ltd., Epotohto YDF-170, YDF-175, YDF-2001 manufactured by Dongdu Chemical Co., Ltd. YDF-2004, bisphenol F-type epoxy resin of Araldite XPY306 (all trade names) manufactured by Ciba Specialty Chemicals Co., Ltd.; Epotohto ST-2004, ST-2007, ST-3000 (trade name) manufactured by Dongdu Chemical Co., Ltd. Hydrogenated bisphenol A type epoxy tree JER604 manufactured by Nippon Epoxy Co., Ltd., Epotohto YH-434 manufactured by Tosho Chemical Co., Ltd., Araldite MY720 manufactured by Ciba Specialty Chemicals Co., Ltd., and Sumiepoxy ELM-120 manufactured by Sumitomo Chemical Industries Co., Ltd. (all trade names) Amine-type epoxy resin; an internal urethane-type epoxy resin such as Araldite CY-350 (trade name) manufactured by Ciba Specialty Chemicals Co., Ltd.; Celoxide 2021 manufactured by DAICEL Chemical Industry Co., Ltd., manufactured by Ciba Specialty Chemicals Co., Ltd. Araldite CY175, CY179, etc. (all trade name) alicyclic epoxy resin; YL-933 made by Japan Epoxy Resin Co., Ltd., TEN, EPPN-501, EPPN-502, etc., manufactured by Ceramic Chemical Co., Ltd. Trihydroxyphenylmethane type epoxy resin; biphenyl phenol type or bisphenol type epoxy resin such as YL-6056, YX-4000, YL-6121 (all trade name) manufactured by Nippon Epoxy Co., Ltd. Such a mixture; EBPS-200 manufactured by Nippon Kayaku Co., Ltd., EPX-30 manufactured by Asahi Kasei Kogyo Co., Ltd., and bisphenol S-type epoxy resin such as EXA-1514 (trade name) manufactured by Dainippon Ink Chemical Industry Co., Ltd.; Bisphenol A novolacs such as JER157S (trade name) manufactured by Oxygen Resin Co., Ltd. Epoxy resin; YL-931 manufactured by Nippon Epoxy Co., Ltd., Araldite 163 manufactured by Ciba Specialty Chemicals Co., Ltd. (all trade names), tetrahydroxyphenylethane type epoxy resin; Ciba Specialty Chemicals Co., Ltd. Araldite PT810, heterogeneous epoxy resin such as TEPIC (trade name) manufactured by Nissan Chemical Industries Co., Ltd.; diglycidyl phthalate resin such as Blenmer DGT manufactured by Nippon Oil & Fats Co., Ltd.; ZX-1063 manufactured by Dongdu Chemical Co., Ltd., etc. Tetraglycidyl xylenyl ethane resin; Naphthyl-containing ring made by Essence Chemical Co., Ltd. ESN-190, ESN-360, and Nippon Ink Chemical Industry Co., Ltd. HP-4032, EXA-4750, EXA-4700, etc. Oxygen resin; epoxy resin having a dicyclopentadiene skeleton such as HP-7200 and HP-7200H manufactured by Dainippon Ink and Chemicals Co., Ltd.; glycidyl methacrylate such as CP-50S and CP-50M manufactured by Nippon Oil & Fats Co., Ltd. a copolymerized epoxy resin; and a copolymerized epoxy resin of cyclohexylmaleimide and glycidyl methacrylate; an epoxy-modified polybutadiene rubber derivative (for example, PB-3600 manufactured by DAICEL Chemical Industry Co., Ltd.) Etc.), CTBN modified epoxy resin (such as Dongdu As manufactured by YR-102, YR-450, etc.) and the like, but these are not defined. These epoxy resins may be used alone or in combination of two or more. Among them, a novolac type epoxy resin, a heterocyclic epoxy resin, a bisphenol A type epoxy resin or a mixture thereof is particularly preferred.

The polyfunctional oxetane compound (D-2) may, for example, be bis[(3-methyl-3-oxetanylmethoxy)methyl]ether or bis[(3-ethyl) 1,-3-oxetanylmethoxy)methyl]ether, 1,4-bis[(3-methyl-3-oxetanylmethoxy)methyl]benzene, 1, 4-bis[(3-ethyl-3-oxetanylmethoxy)methyl]benzene, (3-methyl-3-oxetanyl)methacrylate, (3- Ethyl-3-oxetanyl)methacrylate, (3-methyl-3-oxetanyl)methyl methacrylate, (3-ethyl-3-oxocycle) Butylalkyl)methyl methacrylate or polyfunctional oxetane such as oligomers or copolymers, and oxetane with novolac resin, poly(p-hydroxystyrene) An etherified product of a resin having a hydroxyl group such as a comb-type bisphenol, a calixarene, a cup-resorcinol aromatic hydrocarbon, or a sesquioxane. Further, a copolymer of an unsaturated monomer having an oxetane ring and an alkyl (meth)acrylate may, for example, be mentioned.

The compound (D-3) having two or more cyclic thioether groups in the above-mentioned molecule may, for example, be a bisphenol A type episulfide resin YL7000 manufactured by Nippon Epoxy Co., Ltd., or the like. Further, an episulfide resin in which an oxygen atom of an epoxy group of a novolac type epoxy resin is substituted with a sulfur atom or the like can also be used.

The amount of the thermosetting component (D) having two or more cyclic (thio)ether groups in the molecule is preferably a ring (for one equivalent of the carboxyl group of the carboxyl group-containing resin (A)). The thio)ether group is in the range of 0.6 to 2.5 equivalents, more preferably 0.8 to 2.0 equivalents. When the amount of the thermosetting component (D) having two or more cyclic (thio)ether groups in the molecule is less than 0.6 equivalent, the carboxyl group remains in the residual hardening film, and heat resistance, alkali resistance, and electric resistance are caused. Insulation and the like are lowered, so it is not suitable. On the other hand, when it is more than 2.5 equivalents, since the low molecular weight cyclic (thio)ether group remains in the dried coating film, the strength of the coating film and the like are lowered, which is not preferable.

When the thermosetting component (D) having two or more cyclic (thio)ether groups in the above molecule is used, it is preferred to contain a thermosetting catalyst. Examples of such a thermosetting catalyst include imidazole, 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 4-phenylimidazole, and 1 - an imidazole derivative such as cyanoethyl-2-phenylimidazole or 1-(2-cyanoethyl)-2-ethyl-4-methylimidazole; cyanogen, benzyldimethylamine, 4-( Dimethylamino)-N,N-dimethylbenzylamine, 4-methoxy-N,N-dimethylbenzylamine, 4-methyl-N,N-dimethylbenzylamine, etc. An amine compound, a ruthenium compound such as diammonium adipate or bismuth sebacate; a phosphorus compound such as triphenylphosphine or the like. In addition, as a commercial product, for example, 2MZ-A, 2MZ-OK, 2PHZ, 2P4BHZ, 2P4MHZ (trade name of imidazole-based compound) manufactured by Shikoku Chemical Industrial Co., Ltd., U-CAT3503N and U-CAT3502T manufactured by SANAPRO Co., Ltd. A trade name of a blocked isocyanate compound of dimethylamine, DBU, DBN, U-CATSA102, U-CAT5002 (all bicyclic hydrazine compounds and salts thereof). The thermosetting catalyst of the epoxy resin or the oxetane compound is not particularly limited as long as it can promote the reaction of the carboxyl group of the epoxy group and/or the oxetane group, either alone or Mix two or more types for use. Further, guanamine, acetamide, benzoguanamine, melamine, 2,4-diamino-6-methylpropenyloxyethyl-S-III can also be used. 2-vinyl-4,6-diamino-S-three 2-vinyl-4,6-diamino-S-three ‧Isocyanuric acid adduct, 2,4-diamino-6-methylpropenyloxyethyl-S-three ‧S-three of isocyanuric acid adducts, etc. The derivative is preferably used in combination as a functional compound of the adhesion imparting agent and the aforementioned thermosetting catalyst.

The amount of the thermosetting catalyst is sufficient in a usual amount, for example, for 100 parts by mass of the carboxyl group-containing resin (A) or a thermosetting component having two or more cyclic (thio)ether groups in the molecule. In the case of (D), it is preferably 0.1 to 20 parts by mass, more preferably 0.5 to 15.0 parts by mass.

The photosensitive resin composition of the present invention can be blended with a colorant. As the coloring agent, a conventionally known coloring agent such as red, blue, green, or yellow can be used, and any of a pigment, a dye, and a coloring matter can be used. However, from the viewpoint of a reduction in environmental load and influence on the human body, it is preferred that halogen is not contained.

Blue colorant:

Examples of the blue coloring agent include a phthalocyanine system and an anthraquinone system, and the pigment system is a compound classified as a pigment. Specifically, a color index (CI; dyes and dyes associations as described below) is exemplified. Society of Dyers and Colourists) Issued by: Pigment Blue 15, Pigment Blue 15:1, Pigment Blue 15:2, Pigment Blue 15:3, Pigment Blue 15:4, Pigment Blue 15:6, Pigment Blue 16, Pigment Blue 60.

As the dye system, solvent blue 35, solvent blue 63, solvent blue 68, solvent blue 70, solvent blue 83, solvent blue 87, solvent blue 94, solvent blue 97, solvent blue 122, solvent blue 136, solvent blue 67, Solvent blue 70 and the like. In addition to the above, a metal-substituted or unsubstituted phthalocyanine compound can also be used.

Green colorant:

As the green colorant, phthalocyanine or guanidine is similarly used, and specifically, pigment green 7, pigment green 36, solvent green 3, solvent green 5, solvent green 20, solvent green 28, and the like can be used. In addition to the above, a metal-substituted or unsubstituted phthalocyanine compound can also be used.

Yellow colorant:

Examples of the yellow coloring agent include a monoazo type, a bisazo type, a condensed azo type, a benzimidazolone type, an isoindolinone type, an anthraquinone type, and the like, and specific examples thereof include the following.

Lanthanide: Solvent Yellow 163, Pigment Yellow 24, Pigment Yellow 108, Pigment Yellow 193, Pigment Yellow 147, Pigment Yellow 199, Pigment Yellow 202.

Isoindolinone: Pigment Yellow 110, Pigment Yellow 109, Pigment Yellow 139, Pigment Yellow 179, Pigment Yellow 185.

Condensed azo system: Pigment Yellow 93, Pigment Yellow 94, Pigment Yellow 95, Pigment Yellow 128, Pigment Yellow 155, Pigment Yellow 166, Pigment Yellow 180.

Benzimidazolone: Pigment Yellow 120, Pigment Yellow 151, Pigment Yellow 154, Pigment Yellow 156, Pigment Yellow 175, Pigment Yellow 181.

Monoazo system: Pigment Yellow 1, 2, 3, 4, 5, 6, 9, 10, 12, 61, 62, 62: 1, 65, 73, 74, 75, 97, 100, 104, 105, 111 , 116, 167, 168, 169, 182, 183.

Bisazo: Pigment Yellow 12, 13, 14, 16, 17, 55, 63, 81, 83, 87, 126, 127, 152, 170, 172, 174, 176, 188, 198.

Red colorant:

Examples of the red coloring agent include monoazo, bisazo, azo lake, benzimidazolone, anthracene, diketopyrrolopyrrole, condensed azo, anthraquinone, and quinacridine. Specific examples of the ketone system and the like include the following.

Monoazo system: Pigment Red 1, 2, 3, 4, 5, 6, 8, 9, 12, 14, 15, 16, 17, 21, 22, 23, 31, 32, 112, 114, 146, 147 , 151, 170, 184, 187, 188, 193, 210, 245, 253, 258, 266, 267, 268, 269.

Bisazo: Pigment Red 37, 38, 41.

Single azo lake system: Pigment Red 48:1, 48:2, 48:3, 48:4, 49:1, 49:2, 50:1, 52:1, 52:2, 53:1, 53: 2. 57:1, 58:4, 63:1, 63:2, 64:1, 68.

Benzimidazolone type: Pigment Red 171, Pigment Red 175, Pigment Red 176, Pigment Red 185, Pigment Red 208.

Lanthanide: Solvent Red 135, Solvent Red 179, Pigment Red 123, Pigment Red 149, Pigment Red 166, Pigment Red 178, Pigment Red 179, Pigment Red 190, Pigment Red 194, Pigment Red 224.

Diketopyrrolopyrrole: Pigment Red 254, Pigment Red 255, Pigment Red 264, Pigment Red 270, Pigment Red 272.

Condensed azo system: Pigment Red 220, Pigment Red 144, Pigment Red 166, Pigment Red 214, Pigment Red 220, Pigment Red 221, Pigment Red 242.

Lanthanide: Pigment Red 168, Pigment Red 177, Pigment Red 216, Solvent Red 149, Solvent Red 150, Solvent Red 52, Solvent Red 207.

Quinacridone type: Pigment Red 122, Pigment Red 202, Pigment Red 206, Pigment Red 207, Pigment Red 209.

Further, for the purpose of adjusting the color tone, a coloring agent such as purple, orange, brown, or black may be added.

Specific examples include Pigment Violet 19, 23, 29, 32, 36, 38, 42, Solvent Violet 13, 36, CI Pigment Orange 1, CI Pigment Orange 5, CI Pigment Orange 13, CI Pigment Orange 14, CI Pigment Orange 16. CI Pigment Orange 17, CI Pigment Orange 24, CI Pigment Orange 34, CI Pigment Orange 36, CI Pigment Orange 38, CI Pigment Orange 40, CI Pigment Orange 43, CI Pigment Orange 46, CI Pigment Orange 49, CI Pigment Orange 51, CI Pigment Orange 61, CI Pigment Orange 63, CI Pigment Orange 64, CI Pigment Orange 71, CI Pigment Orange 73, CI Pigment Brown 23, CI Pigment Brown 25, CI Pigment Black 1, CI Pigment Black 7, and the like.

The specific blending ratio of the coloring agent is not affected by the kind of the coloring agent used or the kind of other additives, etc., but in the photosensitive resin composition of the present invention, it is preferred to make the absorbance at 355 nm The dry film thickness of 25 μm was proportionally blended in the range of 0.3 to 1.2. Particularly preferred coloring agents are blue and green for the phthalocyanine, lanthanide, yellow for the lanthanide, red for the diketopyrrolopyrrole, lanthanide, and no halogen atoms. Among these, a red coloring agent and a yellow coloring agent are particularly preferable from the viewpoint of sensitivity and resolution.

In order to increase the physical strength and the like of the coating film of the photosensitive resin composition of the present invention, a filler may be blended as needed. As such a filler, a conventionally known inorganic or organic filler can be used, and particularly, barium sulfate, spheroidal vermiculite, and talc are used. Further, in order to obtain a white appearance or flame retardancy, a metal hydroxide such as titanium oxide, metal oxide or aluminum hydroxide may be used as the filler for filling. The blending amount of the filler is preferably 75% by weight or less, more preferably 0.1% to 60% by weight based on the total amount of the composition. When the amount of the filler is more than 75% by weight based on the total amount of the composition, the viscosity of the insulating composition is increased, coating and moldability are lowered, and the cured product is brittle, which is not preferable.

The amount of the filler to be added is preferably 300 parts by mass or less, more preferably 0.1 to 300 parts by mass, even more preferably 0.1 to 150 parts by mass, per 100 parts by mass of the carboxyl group-containing resin (A). When the amount of the filler is more than 300 parts by mass, the viscosity of the photosensitive resin composition is increased, the printability is lowered, and the cured product is brittle, which is not preferable.

Further, in the photosensitive resin composition of the present invention, an organic solvent can be used for the preparation of the carboxyl group-containing resin (A) or the preparation of the composition, or for coating the substrate or the carrier film to adjust the viscosity.

Examples of such an organic solvent include ketones, aromatic hydrocarbons, glycol ethers, glycol ether acetates, esters, alcohols, aliphatic hydrocarbons, petroleum solvents, and the like. More specifically, ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene, xylene, and tetramethylbenzene; cellosolve, methyl cellosolve, butyl cellosolve, and carbene Glycol ethers such as alcohol, methyl carbitol, butyl carbitol, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol diethyl ether, triethylene glycol monoethyl ether; Esters of ethyl ester, butyl acetate, dipropylene glycol methyl ether acetate, propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, propylene glycol butyl ether acetate; ethanol, propanol, ethylene glycol, propylene glycol An alcohol such as an aliphatic hydrocarbon such as octane or decane; a petroleum solvent such as petroleum ether, petroleum brain, hydrogenated petroleum brain or solvent oil. Such an organic solvent may be used singly or as a mixture of two or more kinds.

The photosensitive resin composition of the present invention may be further blended with hydroquinone, hydroquinone monomethyl ether, tert-butylcatechol, pyrocatechol, and thiophene as needed. A known conventionally used tackifier, such as a thermal polymerization inhibitor, a fine vermiculite, an organic bentonite, or a montmorillonite, a defoaming agent such as a polyfluorene-based, a fluorine-based or a polymer-based, and/or a leveling agent. A well-known and customary additive such as a decane coupling agent such as an imidazole type, a thiazole type or a triazole type, an antioxidant, or a rust preventive agent.

The photosensitive resin composition of the present invention may be in the form of a dry film, and includes a carrier film (support) and a layer formed of the photosensitive resin composition formed on the carrier film.

At the time of dry film formation, the photosensitive resin composition of the present invention is diluted with the above organic solvent to adjust the viscosity to a proper viscosity by a comma coater, a knife coater, a lip coater, and a bar coater. , extrusion coater, reverse coater, transfer roll coater, gravure roll coater, sprayer, etc., coated on the carrier film with a uniform thickness, usually dried at 50~130 ° C for 1~30 minutes , a film is available. The coating film thickness is not particularly limited, and is generally selected from the range of 10 to 150 μm, preferably 20 to 60 μm after drying.

As the carrier film, a plastic film is used, and a polyester film such as polyethylene terephthalate, a polyimide film, a polyimide film, a polypropylene film, a polystyrene film, or the like is preferably used. Plastic film. The thickness of the carrier film is not particularly limited, and is generally suitably selected in the range of 10 to 150 μm.

After the film is formed on the carrier film, it is more preferable to laminate the peelable cover film on the surface of the film for the purpose of preventing dust from adhering to the surface of the film.

As the peelable cover film, for example, a polyethylene film, a polytetrafluoroethylene film, a polypropylene film, a surface-treated paper, or the like can be used, as long as the adhesive film of the film and the cover film is smaller than the carrier when the cover film is peeled off. The adhesion of the film is sufficient.

The liquid photosensitive resin composition of the present invention having the above composition may be adjusted to a viscosity suitable for a coating method by the above-mentioned organic solvent, and may be subjected to dip coating, flow coating, or roll coating on a substrate. Coating by a method such as a method, a bar coating method, a screen printing method, or a curtain coating method, and the organic solvent contained in the composition is volatilized and dried (temporarily dried) at a temperature of about 60 to 100 ° C to form a film. Sticky coating. Moreover, in the dry film form, it is bonded to the base material using a hot roll laminator or the like (the photosensitive resin composition layer is bonded to the substrate so as to be in contact with each other). When the dry film of the peelable cover film is further provided on the photosensitive resin composition layer of the film, after the cover film is peeled off, the photosensitive resin composition layer is brought into contact with the substrate so that hot roll lamination is used. Machines and so on.

Then, the obtained coating film (photosensitive resin composition layer) (when the dry film is used, the carrier film is not peeled off after being laminated on the substrate), and exposure (irradiation of active energy rays) is performed. The exposure system may be a contact type (or non-contact method), a method of forming a pattern through a photomask, a selective exposure by an active energy line, or a direct pattern exposure by a laser direct exposure machine. Any of them. By this exposure, the exposed portion of the coating film (the portion irradiated by the active energy ray) is hardened. Next, the unexposed portion is developed by a dilute aqueous alkali solution (for example, 0.3 to 3% aqueous sodium carbonate solution) to form a resist pattern (when the dry film is used, after exposure, the carrier film is peeled off and developed). Then, it is only heat-hardened, or is subjected to heat-hardening or heat-hardening after irradiation with an active energy ray, and then the active energy ray is irradiated to cause final hardening (this hardening), thereby forming electrical insulation, adhesion, solder heat resistance, and chemical resistance. An excellent hardened film (hardened material) such as electroless gold plating resistance. In the case of the photosensitive resin composition containing the thermosetting component (D), for example, by heat-heating to a temperature of about 140 to 180 ° C, the carboxyl group and the molecule of the carboxyl group-containing resin (A) can be obtained. The thermosetting component (D) having two or more cyclic ether groups and/or a cyclic thioether group reacts to form excellent properties such as heat resistance, chemical resistance, moisture absorption resistance, adhesion, and electrical properties. Harden the membrane.

As the above substrate, a printed circuit board in which a circuit is formed in advance, in particular, a flexible printed circuit board, and paper-phenol resin, paper-epoxy resin, glass cloth-epoxy resin, glass-polyimine, glass can be used. Cloth/non-woven fabric-epoxy resin, glass cloth/paper-epoxy resin, synthetic fiber-epoxy resin, fluororesin, bismuth polyethylene, ̇PPO phthalocyanate, etc. All grades (FR-4, etc.) A copper clad laminate, a polyimide film, a PET film, a glass substrate, a ceramic substrate, a wafer plate, or the like.

The volatilization drying performed after applying the photosensitive resin composition of the present invention may be a hot air circulation type drying furnace, an IR furnace, a heating plate, a convection oven, or the like (a heat source having a steam heating air method is used to make a countercurrent contact dryer) The method of hot air inside, or the method of blowing the support by a nozzle).

The exposure machine used for the active energy ray irradiation may be a device that irradiates ultraviolet rays in the range of 350 to 450 nm, such as a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a metal halide lamp, or a short arc mercury lamp, and may be a direct drawing device ( For example, a laser direct imaging device that draws an image by direct laser imaging from CAD data from a computer). As the laser light source of the direct drawing machine, laser light having a maximum wavelength in the range of 350 to 410 nm can be used, and any of a gas laser and a solid laser can be used. The exposure amount for image formation varies depending on the film thickness and the like, and is generally 20 to 800 mJ/cm ² , preferably 20 to 600 mJ/cm ² .

As the developing method, a dipping method, a shower method, a spray method, a brush method, or the like can be used; as the developing solution, potassium hydroxide, sodium hydroxide, sodium carbonate, potassium carbonate, sodium phosphate, sodium citrate can be used. An aqueous alkali solution such as ammonia or an amine.

[Examples]

The present invention will be specifically described by the following examples and comparative examples, but the present invention is of course not limited by the following examples. Furthermore, the following "parts" and "%" are based on quality unless otherwise specified.

Synthesis Example 1

(A-1) a synthesis of a photosensitive carboxyl group-containing urethane resin having a bisphenol A structure using an alicyclic diisocyanate corresponding to the carboxyl group-containing resin (3): in a separable flask, 368.0 g of RE310S (2-functional bisphenol A type epoxy resin, epoxy equivalent: 184 g/eq.), 142.7 g of acrylic acid (molecular weight: 72.06), which is a bisphenol A type epoxy compound, was prepared. 2.94 g of 2,6-di-t-butyl-p-cresol as a thermal polymerization inhibitor and 1.53 g of triphenylphosphine as a reaction catalyst, the acid value of the reaction solution was changed to 0.5 mgKOH/g at a temperature of 98 °C. Hereinafter, the epoxy carboxylate compound (a) (theoretical molecular weight: 510.7) was obtained. Next, 588.2 g of carbitol acetate as a reaction solvent and 105.5 g of dimethylolpropionic acid (b) (molecular weight: 134.16) were added to the reaction mixture, and the temperature was raised to 45 °C. In this solution, 264.7 g of isophorone diisocyanate (c) (molecular weight: 222.28) was slowly added so that the reaction temperature did not exceed 65 °C. After the completion of the dropwise addition, the temperature was raised to 80 ° C, and the reaction was allowed to proceed for 6 hours until the absorption in the vicinity of 2250 cm ^{-1 was} not obtained by infrared absorption spectrometry, and the temperature was further lowered at 98 ° C for 2 hours to obtain 60% by weight. A resin solution of an aqueous alkali solution soluble urethane resin. The acid value was measured and found to be 28.9 mgKOH/g (solid content acid value: 48.1 mgKOH/g). Hereinafter, this reaction product was referred to as a resin solution (A-1).

Synthesis Example 2

(A-2) A synthesis of a photosensitive carboxyl group-containing urethane resin having a bisphenol F structure using an alicyclic diisocyanate corresponding to the carboxyl group-containing resin (3): 169 parts (0.5 mol) Bisphenol F type epoxy resin (R110, manufactured by Mitsui Chemicals Co., Ltd., epoxy equivalent 169 g/eq), 36 parts (0.5 mol) of acrylic acid, 74 parts (0.5 mol) of dimethylol Butyric acid, 0.10 parts of methylhydroquinone, and 185 parts of carbitol acetate were heated to 100 ° C. After confirming that the mixture was uniformly dissolved, 3.0 parts of triethylamine was added, and the mixture was heated to 110 ° C to react for about 25 hours. . Then, the reaction product was cooled to room temperature, and 152 parts (1.0 mol) of tetrahydrophthalic anhydride was charged, and the mixture was heated to 100 ° C to carry out a reaction for about 5 hours to obtain an acid anhydride-modified epoxy acrylate (d). Next, 832.5 parts (3.75 mol) of isophorone diisocyanate, 747 parts (0.75 mol) of polycarbonate polyol (PMHC-1050, manufactured by KURARAY), and 222 parts were charged under a nitrogen atmosphere. (1.5 mol) of dimethylolbutanoic acid, 1662 parts of carbitol acetate, and 6.5 parts of dibutyltin dilaurate were heated to 70 ° C to allow a reaction for about 8 hours. After stopping the nitrogen flow, the reaction mixture was cooled to room temperature, and 2463 parts (2.0 mol) of the above anhydride-modified epoxy acrylate (d) was charged under a dry air flow, and heated to 80 ° C to react. 6 hours. Then, the reaction product was cooled to room temperature, and 76 parts (0.5 mol) of tetrahydrophthalic anhydride was charged, and the mixture was heated to 110 ° C to carry out a reaction for about 4 hours to obtain a solid content acid value of 93.5 mgKOH/g, and a solid content. A carboxyl group-containing urethane resin having a concentration of 60%. Hereinafter, this reaction product was referred to as a resin solution (A-2).

Synthesis Example 3

(A-3) corresponds to the carboxyl group-containing resin (4), and is a synthesis of a photosensitive carboxyl group-containing urethane resin using an alicyclic diisocyanate: in a reaction vessel equipped with a stirring device, a thermometer, and a condenser 2400 g (3 mol) of polycarbonate diol derived from 1,5-pentanediol and 1,6-hexanediol (manufactured by Asahi Kasei Chemicals Co., Ltd., number average molecular weight 800), 603 g ( 4.5 moles of dimethylolpropionic acid and 238 grams (2.6 moles) of 2-hydroxyethyl acrylate as a monohydroxy compound. Next, 1887 g (8.5 mol) of isophorone diisocyanate as a polyisocyanate was charged, and it was stopped by heating to 60 ° C with stirring, and heated again at the time when the temperature in the reaction container began to decrease, and continued at 80 ° C. After stirring, it was confirmed by infrared absorption spectrum that the absorption spectrum (2280 cm ^-1 ) of the isocyanate group disappeared, and the reaction was terminated. Carbitol acetate was added so that the solid content became 50% by mass. The solid content of the obtained photosensitive carboxyl group-containing urethane resin was 50 mgKOH/g. Hereinafter, this reaction product was referred to as a resin solution (A-3).

(A-4) Corresponding to the carboxyl group-containing resin (6), a photosensitive carboxyl group-containing resin using a biphenyl novolak epoxy resin having a biphenyl skeleton: ZCR-1601H (solid) manufactured by Nippon Kayaku Co., Ltd. A resin solution having an acid value of 98 mg KOH/g of 65% resin was used as A-4.

(A-5) A carboxyl group-containing resin corresponding to the carboxyl group-containing resin (7) and a polyfunctional epoxy resin having a bisphenol F structure: ZFR-1124 (solid content 63) manufactured by Nippon Kayaku Co., Ltd. A resin solution having an acid value of 102 mgKOH/g of % resin was regarded as A-5.

Examples 1 to 7 and Comparative Examples 1 to 3

Each of the resin solutions (A-1) to (A-5) described above was blended with the various components shown in Table 1 in the proportions (mass parts) shown in Table 1 below, and prepared by mixing in a stirrer. The three-roll mill is kneaded to prepare a photosensitive resin composition for the solder resist. Here, the degree of dispersion of the obtained photosensitive resin composition was evaluated by particle size measurement by a grind meter manufactured by Erichsen Co., Ltd., and all the compositions were 15 μm or less.

Performance evaluation: <Optimum exposure/sensitivity>

The circuit pattern substrate having a copper thickness of 35 μm was pickled, washed with water, and after drying, the photosensitive resin composition of each of the above examples and comparative examples was completely applied by screen printing, and the hot air circulation type at 80 ° C was applied. Dry in a drying oven for 60 minutes. After drying, a direct drawing device equipped with a semiconductor laser having a maximum wavelength of 355 nm, an exposure device equipped with a short arc mercury lamp, and a direct drawing machine equipped with a high pressure mercury lamp were used, and exposed by a step wedge (Kodak No. 2). When the development was carried out for 60 seconds at a spray pressure of 0.2 MPa by a 1 wt% sodium carbonate aqueous solution at 30 ° C, the pattern of the remaining step wedges was regarded as the optimum exposure amount when the pattern was 6 stages.

<resolution>

A circuit pattern substrate having a line/gap of 300/300 μm and a copper thickness of 35 μm was polished by a polishing roll, washed with water, and after drying, the photosensitive resin composition of each of the foregoing examples and comparative examples was applied by screen printing. The material was dried in a hot air circulating drying oven at 80 ° C for 30 minutes. After drying, exposure was performed using a direct drawing device equipped with a semiconductor laser having a maximum wavelength of 355 nm. The exposure pattern uses data for direct drawing of a line of 20/30/40/50/60/70/80/90/100 μm for the gap portion. The active energy ray is irradiated so that the exposure amount becomes the most suitable exposure amount of the photosensitive resin composition. After the exposure, the pattern was drawn by development using a 1 wt% sodium carbonate aqueous solution at 30 ° C, and heat curing was performed at 150 ° C for 60 minutes to obtain a cured coating film.

The minimum residual line of the cured coating film of the obtained photosensitive resin composition for solder resist was obtained using an optical microscope adjusted to 200 times.

<absorbance>

The absorbance was measured using an ultraviolet-visible spectrophotometer (Ubest-V-570Ds manufactured by JASCO Corporation) and an integrating sphere device (ISN-470 manufactured by JASCO Corporation). The photosensitive resin composition of each of the above Examples and Comparative Examples was applied onto a glass plate using a coater, and then dried at 80 ° C for 30 minutes in a hot air circulating drying oven to prepare a photosensitive resin composition on a glass plate. Dry coating of the material. The absorbance baseline at 500 to 300 nm was measured using an ultraviolet-visible spectrophotometer and an integrating sphere device on the same glass plate as the glass plate coated with the photosensitive resin composition. The absorbance of the glass plate with the dried coating film produced was measured, and the absorbance of the dried coating film was calculated from the baseline to obtain the absorbance at a target light wavelength of 355 nm. In order to prevent the variation in the absorbance due to the variation in the thickness of the coating film, the coating thickness was changed to four stages by a coater, and a graph of the coating thickness and the absorbance at 355 nm was prepared, and the film was calculated from the approximate expression. The absorbance of the dried coating film having a thickness of 25 μm was taken as the respective absorbance.

Characteristic test

Evaluation of substrate production method: The photosensitive resin composition of each of the above examples and comparative examples was applied by screen printing on a polyimide substrate having a copper circuit, and dried at 80 ° C for 20 minutes, and allowed to stand for cooling. Until room temperature. For this substrate, an exposure apparatus equipped with a short-arc mercury lamp was used to expose the solder resist pattern at the most appropriate exposure amount, and the solution was carried out under a nozzle pressure of 0.2 MPa by a 1 wt% Na ₂ CO ₃ aqueous solution at 30 ° C. Second impression, and a resist pattern is obtained. The substrate was cured by heating at 150 ° C for 60 minutes. The following characteristics were evaluated about the obtained flexible wiring board (evaluation substrate).

<Color of coating film>

The color of the cured product was visually observed for the resist patterns of the above respective examples and comparative examples.

<solder heat resistance>

The evaluation substrate coated with the rosin-based flux was immersed in a solder bath set at 260 ° C in advance, and after modifying the alcohol to clean the flux, the flaking and peeling of the side resist layer was visually observed. The criterion for determination is as follows.

○: The immersion was carried out for 10 seconds, and even if the peeling test was carried out with the cellophane adhesive tape, no peeling was observed.

Δ: The immersion was carried out for 10 seconds, and if the peeling test was carried out with the cellophane adhesive tape, it peeled off a little.

X: If the etching is performed for 10 seconds, the resist layer may swell and peel off.

<electroless gold plating resistance>

The evaluation substrate was subjected to electroless nickel plating bath and electroless gold plating bath under the conditions of nickel 0.5 μm and gold 0.03 μm, and peeled off by a tape to evaluate the presence or absence of peeling of the resist layer or presence or absence of plating. After the infiltration of the material, the peeling of the resist layer was evaluated by tape peeling. The criterion for determination is as follows.

○: The infiltration of the plating material and the peeling of the resist layer were not observed.

Δ: Only slight infiltration was observed after plating, and peeling of the resist layer was also observed after the tape was peeled off.

×: Peeling of the resist layer after plating.

<Electrical corrosion resistance>

In place of the copper foil substrate, an evaluation electrode substrate was produced under the above conditions using a comb-shaped electrode B sample of IPC B-25, and a bias voltage of DC 100 V was applied to the comb-shaped electrode to confirm a constant temperature and humidity chamber at 85 ° C and 85% RH. There is no migration after 1,000 hours. The criterion for determination is as follows.

○: Almost no changers are seen

Δ: discoloration

×: The mover occurred

<acid resistance>

The evaluation substrate was immersed in a 10 vol% H ₂ SO ₄ aqueous solution at room temperature for 30 minutes, and the penetration of the aqueous sulfuric acid solution or the elution of the coating film and the peeling of the resist layer due to the tape peeling were confirmed. The criterion for determination is as follows.

○: There was no infiltration of a sulfuric acid aqueous solution, elution of a coating film, and peeling of a resist layer.

Δ: The infiltration of a small amount of the sulfuric acid aqueous solution, the elution of the coating film, or the peeling of the resist layer were confirmed.

X: The infiltration of the aqueous sulfuric acid solution, the elution of the coating film, or the large peeling of the resist layer was confirmed.

<warp>

The photosensitive resin composition was completely coated on a 50 μm-thick polyimine film (Kapton 300H) by screen printing, dried at 80 ° C for 20 minutes, and left to cool to room temperature. For this substrate, an exposure device equipped with a short-arc mercury lamp was used, and the solder resist pattern was applied at an optimum exposure amount by a 1 wt% Na ₂ CO ₃ aqueous solution at 30 ° C for 60 seconds under a nozzle pressure of 0.2 MPa. Visualization, and a resist pattern is obtained. The substrate was cured by heating at 150 ° C for 60 minutes. From the obtained film, 10 cm × 10 cm was cut out, and the amount of warpage was measured.

Further, the amount of warpage of the film after heating the film in a hot air drying oven at 170 ° C for 2 hours was measured in the same manner. (the amount of warpage after heating)

The evaluation results are shown in Table 2 and Table 3.

Implementation side 8<dry film evaluation>

The composition used in Example 3 was diluted with methyl ethyl ketone, coated on a PET film, and dried at 80 ° C for 30 minutes to form a photosensitive resin composition layer having a dry thickness of 25 μm. A cover film is then adhered thereon to obtain a dry film. Then, the cover film was peeled off, and the pattern was formed on a copper foil substrate having a circuit thickness of 35 μm, and the film was thermally laminated, followed by a direct drawing device equipped with a semiconductor laser having a maximum wavelength of 355 nm, at 150 mj/cm ² . Exposure. After the exposure, the carrier film was peeled off and heat-hardened by a hot air dryer at 150 ° C for 60 minutes to prepare a test substrate. The test substrate having the hardened film obtained was subjected to an evaluation test of each characteristic by the above test method and evaluation method.

As a result, results substantially similar to those of Example 3 shown in Table 3 were obtained.

As shown in the above Tables 2 and 3, in Examples 1 to 7 and 8 of the present invention using an oxime ester-based photopolymerization initiator, occurrence of warpage after heat curing and after heating can be suppressed. On the other hand, in Comparative Examples 1 to 3 in which a photopolymerization initiator other than the oxime ester type was used, it was not possible to suppress the occurrence of warpage after heat curing and after heating, especially in the case of non-volatile other than the oxime ester type. In Comparative Example 2 of the photopolymerization initiator, the absorbance was high, and the occurrence of warpage after the post-heating was remarkable. Further, in Comparative Example 3 in which a relatively small amount of a photopolymerization initiator other than the oxime ester system was used, since the curing was insufficient, the solder heat resistance was inferior.

Claims (12)

A photosensitive resin composition characterized in that it contains (A) a carboxyl group-containing resin having a structure of bisphenol A, bisphenol F, biphenyl, a bixylenol skeleton or a hydrogenated skeleton thereof, and (B) The oxime ester-based photopolymerization initiator represented by the following formula (I) and the (C) compound having two or more ethylenically unsaturated groups in the molecule which can be visualized by a dilute aqueous alkali solution The above-mentioned oxime ester-based photopolymerization initiator (B) is contained in an amount of 0.1 to 1.5 parts by mass based on 100 parts by mass of the above carboxyl group-containing resin (A); (wherein R ¹ represents a hydrogen atom, a phenyl group (which may be substituted by an alkyl group having 1 to 6 carbon atoms, a phenyl group or a halogen atom), or an alkyl group having 1 to 20 carbon atoms (which may be one or more hydroxyl groups) Substituting, there may be one or more oxygen atoms in the middle of the alkyl chain), a cycloalkyl group having 5 to 8 carbon atoms, an alkanoyl group having 2 to 20 carbon atoms or a benzhydryl group (a carbon number of 1 to 6) Alkyl or phenyl substituted), R ² represents a phenyl group (which may be substituted by an alkyl group having 1 to 6 carbon atoms, a phenyl group or a halogen atom), and an alkyl group having 1 to 20 carbon atoms (more than one or more) Substituted by a hydroxyl group, may have one or more oxygen atoms in the middle of the alkyl chain), a cycloalkyl group having 5 to 8 carbon atoms, an alkanoyl group having 2 to 20 carbon atoms, or a benzhydryl group (carbon number per pass) 1~6 alkyl or phenyl substituted)). The photosensitive resin composition of claim 1, wherein the carboxyl group-containing resin (A) further has an urethane structure. The photosensitive resin composition of the first aspect of the invention, wherein the carboxyl group-containing resin (A) is a resin having two or more radical polymerizable unsaturated double bonds. The photosensitive resin composition of the first aspect of the invention, wherein the oxime ester-based photopolymerization initiator (B) is an oxime ester-based photopolymerization initiator represented by the following formula (V), The photosensitive resin composition of the first aspect of the invention, wherein the oxime ester-based photopolymerization initiator (B) is an oxime ester-based photopolymerization initiator represented by the following formula (VI), (In the formula, R ¹⁰ represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, a cyclopentyl group, a cyclohexyl group, a phenyl group, a benzyl group, a benzamyl group, an alkanoyl group having 2 to 12 carbon atoms, The alkoxycarbonyl group having 2 to 12 carbon atoms (when the number of carbon atoms of the alkyl group constituting the alkoxy group is 2 or more, the alkyl group may be substituted by one or more hydroxyl groups, and one or more of the alkyl chains may be present in the middle of the alkyl chain. An oxygen atom) or a phenoxycarbonyl group; R ¹¹ and R ¹³ each independently represent a phenyl group (which may be substituted by an alkyl group having 1 to 6 carbon atoms, a phenyl group or a halogen atom), and an alkyl group having 1 to 20 carbon atoms. Substituted by one or more hydroxyl groups, one or more oxygen atoms may be present in the middle of the alkyl chain), a cycloalkyl group having 5 to 8 carbon atoms, an alkanoyl group having 2 to 20 carbon atoms or a benzhydryl group ( It can be substituted by an alkyl group having 1 to 6 carbon atoms or a phenyl group; R ¹² represents a hydrogen atom, a phenyl group (which may be substituted by an alkyl group having 1 to 6 carbon atoms, a phenyl group or a halogen atom), and a carbon number of 1~ 20 alkyl group (which may be substituted by one or more hydroxyl groups, may have one or more oxygen atoms in the middle of the alkyl chain), a cycloalkyl group having 5 to 8 carbon atoms, or an alkyl fluorenyl group having 2 to 20 carbon atoms Or a benzamidine group (which may be substituted by an alkyl group having 1 to 6 carbon atoms or a phenyl group)). The photosensitive resin composition of the first aspect of the invention, wherein the photopolymerization initiator contains a photopolymerization initiator (B) which volatilizes at 50 ° C or more at 150 ° C as a photopolymerization initiator (B). B1a). The photosensitive resin composition of claim 1, wherein the thermosetting component (D) is further contained. The photosensitive resin composition according to any one of claims 1 to 7, wherein the dry coating film has an absorbance at 355 nm in a range of 0.3 to 1.2 in a dry film thickness of 25 μm. A photosensitive dry film obtained by drying a photosensitive resin composition according to any one of claims 1 to 8 after drying on a carrier film. A cured product obtained by photohardening a photosensitive resin composition according to any one of claims 1 to 8 or a dry film of claim 9 in copper. A cured product characterized by the photosensitive resin composition according to any one of claims 1 to 8 or the dry film of claim 9 of the patent application, which is photohardened by a laser oscillating light source. . A printed circuit board characterized by having a photosensitive resin composition according to any one of claims 1 to 8 or a ninth application of the ninth aspect of the patent application by the laser light having a maximum wavelength of 350 to 410 nm. After the film is photohardened, it is hardened by heat to obtain a hardened film.