JP2006259150A - Photosensitive resin composition and printed wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photosensitive resin composition capable of forming an image by ultraviolet exposure and development with a dilute alkaline aqueous solution, having good sensitivity, excellent also in tackiness, removability, acid resistance, plating resistance and heat resistance, and excellent in photocuring property in the air without generating mist in curing. <P>SOLUTION: The photosensitive resin composition contains (A) an active energy line-curing resin having at least two ethylenically unsaturated bonds per molecule, (B) a photopolymerization initiator containing at least an oxime-based photopolymerization initiator, (C) a diluent, (D) a thermosetting compound and (E) mercaptopropionic acid or a derivative thereof. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention can form an image by ultraviolet exposure and development with a dilute alkaline aqueous solution, has high sensitivity, is excellent in tackiness, removability, acid resistance, plating resistance, heat resistance, and does not generate mist during curing. The present invention relates to a photosensitive resin composition excellent in photocuring property and a printed wiring board using the same.

  A printed wiring board is for mounting a circuit pattern on a circuit board by soldering an electronic component to the soldering land of the pattern, and the circuit part excluding the soldering land is permanent. It is coated with a solder resist film as a protective film. This prevents solder from adhering to unnecessary parts when soldering electronic components to a printed wiring board, and prevents circuit conductors from being directly exposed to air and being corroded by oxidation or humidity. .

With the demand for higher wiring density (miniaturization) of printed wiring boards, solder resist compositions are also required to have high resolution and high precision. A liquid photo solder resist method (photographic development method) that is excellent in accuracy and coverage of conductor edge portions has been proposed. For example, Patent Document 1 discloses a solder resist composition comprising a bisphenol type epoxy acrylate, a sensitizer, an epoxy compound, an epoxy curing agent, and the like. These solder resist compositions are applied to the entire surface of a liquid composition, which is a photosensitive resin composition, on a printed wiring board, and after volatilizing the solvent, it is exposed to remove unexposed portions using an organic solvent, Develop.
However, the removal (development) of unexposed areas with organic solvents is not only dangerous for the environment and fire, but also has a problem of environmental pollution, especially because it uses a large amount of organic solvent. Countermeasures have been taken since the impact has been greatly highlighted recently.
JP-A-50-144431

In order to solve these problems, an alkali development type photo solder resist composition that can be developed with a dilute aqueous alkali solution has been proposed. For example, Patent Document 2 discloses a material based on a reaction product obtained by reacting an unsaturated monocarboxylic acid with an epoxy resin and further adding a polybasic acid anhydride. Patent Document 3 discloses an active energy ray-curable resin obtained by reacting a reaction product of a novolac type epoxy resin and an unsaturated monocarboxylic acid with a saturated or unsaturated polybasic acid anhydride, and photopolymerization. A photocurable liquid resist ink composition that can be developed with a dilute alkaline aqueous solution containing an initiator is disclosed.
JP 49-5923 A JP-A 61-243869

These liquid solder resist compositions are provided with photosensitivity and developability in a dilute alkaline aqueous solution by introducing a carboxyl group into epoxy acrylate. The composition is further subjected to exposure and development treatment to form a desired resist pattern, and then usually heat-cured. In this process, a volatile component (mist) generated from the resist ink is deposited in a low temperature portion of a thermosetting furnace or piping. In such a case, problems such as the piping path being blocked by the deposited crystal substance and the deposit falling on the printed circuit board occur, so that it does not volatilize during the printed wiring board manufacturing process. A photosensitive resin composition using an oxime photoinitiator has been developed.
JP 2001-233842 A JP 2001-302871 A JP 2003-280193 A

  An oxime photoinitiator is known as a material that does not generate mist, has high photosensitivity required for a photosensitive resin composition, and has excellent resolution. However, when an oxime-based photopolymerization initiator is used as a photoinitiator for a solder resist, its thermal stability is low, so the developability with a dilute alkaline aqueous solution is lowered after preliminary drying, and the removability of non-exposed areas is extremely high. Adversely affect.

  The object of the present invention is that images can be formed by ultraviolet exposure and development with a dilute aqueous alkali solution, which has good sensitivity, excellent tackiness, removability, acid resistance, plating resistance, and heat resistance, and does not generate mist during curing. It is providing the photosensitive resin composition excellent in the photocurability in air | atmosphere.

  Moreover, the subject of this invention is providing the printed wiring board before or after electronic component mounting which has the cured film of the soldering resist film | membrane of such a photosensitive resin composition.

  The photosensitive resin composition according to the present invention comprises (A) an active energy ray-curable resin having at least two ethylenically unsaturated bonds in one molecule, (B) an oxime photopolymerization initiator, and (C) dilution. Agent, (D) a thermosetting compound, and (E) mercaptopropionic acid or a derivative thereof.

  In addition, the present invention relates to a printed wiring board before or after mounting an electronic component, characterized by having a cured film of the photosensitive resin composition.

  According to the present invention, since the oxime photoinitiator is used, no component (mist) that volatilizes from the solder resist during the printed wiring board manufacturing process is generated. In addition to that, by adding the (E) mercaptopropionic acid derivative, it is excellent in developability in dilute alkaline aqueous solution, excellent in heat resistance, acid resistance, plating resistance, and excellent in photocurability in the atmosphere. A photosensitive resin film suitable as a solder resist for producing a printed wiring board can be provided.

  However, it was found that when the (E) mercaptopropionic acid derivative was added to the composition, the copper foil was easily oxidized. Therefore, it was discovered that when the composition is further used with (F) monofunctional methacrylate antioxidant, oxidation of the copper foil is prevented.

  In addition, when the (E) mercaptopropionic acid derivative was added to the composition, the standing life of the composition was extended as compared with the case where this was not added, but by further using (G) a benzothiazole-based corrosion inhibitor, It has been found that the shelf life of the composition is significantly improved.

  Further, in the composition, (E) a mercaptopropionic acid derivative, (F) a monofunctional methacrylate antioxidant, and (G) a benzothiazole-based corrosion inhibitor are used in combination with the above-described effects of the present invention. Furthermore, it was found that the oxidation of the copper foil can be prevented and the shelf life of the composition can be significantly extended, and the present invention has been completed. Such a composition is extremely suitable as a solder resist for producing a printed wiring board, and has a great industrial utility value.

  In the present invention, “(A) an active energy ray-curable resin having at least two ethylenically unsaturated bonds in one molecule” is a curable resin having a plurality of ethylenically unsaturated groups in the molecule. There is no particular limitation. For example, at least part of the epoxy group of a polyfunctional epoxy resin having two or more epoxy groups in the molecule is reacted with a radically polymerizable unsaturated monocarboxylic acid such as acrylic acid or methacrylic acid, and then the resulting hydroxyl group is polybasic. What reacted with the acid anhydride etc. can be mentioned.

Any polyfunctional epoxy resin can be used as long as it is a bifunctional or higher functional epoxy resin, and there is no particular limitation on the epoxy equivalent, but usually 1,000 or less, preferably 100-500.
For example, phenol novolak type epoxy resins such as bisphenol A type, bisphenol F type and bisphenol AD type, cresol novolac type epoxy resins such as о-cresol novolak type, bisphenol A novolac type epoxy resins, cycloaliphatic polyfunctional epoxy resins, glycidyl Ester-type polyfunctional epoxy resins, glycidylamine-type polyfunctional epoxy resins, heterocyclic polyfunctional epoxy resins, bisphenol-modified novolac-type epoxy resins, polyfunctional-modified novolak-type epoxy resins, phenols and aromatic aldehydes having phenolic hydroxyl groups And the condensate type epoxy resin. Further, those obtained by introducing halogen atoms such as Br and Cl into these resins are also included. Among these, considering heat resistance, novolac type epoxy resin is preferable. These epoxy resins may be used alone or in combination of two or more.

  When these epoxy resins are reacted with radically polymerizable unsaturated monocarboxylic acid, the epoxy group is cleaved by the reaction of the epoxy group and the carboxyl group to form a hydroxyl group and an ester bond. The radical polymerizable unsaturated monocarboxylic acid to be used is not particularly limited and includes, for example, acrylic acid, methacrylic acid, crotonic acid, cinnamic acid, etc., but at least one of acrylic acid and methacrylic acid (hereinafter referred to as (meth) acrylic). It is sometimes referred to as an acid.), And acrylic acid is particularly preferable. There is no restriction | limiting in particular in the reaction method of an epoxy resin and radically polymerizable unsaturated monocarboxylic acid, For example, it can react by heating an epoxy resin and acrylic acid in a suitable diluent. Examples of the diluent include ketones such as methyl ethyl ketone and cyclohexanone, aromatic hydrocarbons such as toluene and xylene, alcohols such as methanol, isopropanol and cyclohexanol, and alicyclic hydrocarbons such as cyclohexane and methylcyclohexane. Petroleum solvents such as petroleum ether and petroleum naphtha, cellosolves such as cellosolve and butylcellosolve, carbitols such as carbitol and butylcarbitol, ethyl acetate, butyl acetate, cellosolve acetate, butyl cellosolve acetate, carbitol acetate, butyl Examples include acetates such as carbitol acetate. Examples of the catalyst include amines such as triethylamine and tributylamine, and phosphorus compounds such as triphenylphosphine and triphenylphosphate.

  In the reaction between the epoxy resin and the radically polymerizable unsaturated monocarboxylic acid, it is preferable to react 0.7 to 1.2 equivalents of the radically polymerizable unsaturated monocarboxylic acid per 1 equivalent of the epoxy group of the epoxy resin. When at least one of acrylic acid or methacrylic acid is used, 0.8 to 1.0 equivalent is more preferably added and reacted. If the radically polymerizable unsaturated monocarboxylic acid is less than 0.7 equivalent, gelation may occur during the synthesis reaction in the subsequent step, or the stability of the resin is lowered. Further, if the radically polymerizable unsaturated monocarboxylic acid is excessive, a large amount of unreacted carboxylic acid remains, which may reduce various properties (for example, water resistance) of the cured product. The reaction between the epoxy resin and the radically polymerizable unsaturated monocarboxylic acid is preferably performed in a heated state, and the reaction temperature is preferably 80 to 140 ° C. If the reaction temperature exceeds 140 ° C, the radically polymerizable unsaturated monocarboxylic acid is likely to undergo thermal polymerization and may be difficult to synthesize, and if it is less than 80 ° C, the reaction rate will be slow, which is undesirable in actual production. There is.

  In the reaction of the epoxy resin and the radically polymerizable unsaturated monocarboxylic acid in the diluent, the blending amount of the diluent is preferably 20 to 50% with respect to the total weight of the reaction system. The reaction product of the epoxy resin and the radically polymerizable unsaturated monocarboxylic acid can be subjected to the reaction with the next polybasic acid in the form of a diluent without isolation.

  A polybasic acid or an anhydride thereof is reacted with the unsaturated monocarboxylic oxide epoxy resin which is a reaction product of the epoxy resin and the radically polymerizable unsaturated monocarboxylic acid. There is no restriction | limiting in particular as a polybasic acid or its anhydride, Either saturated and unsaturated can be used. Examples of such polybasic acids include succinic acid, maleic acid, adipic acid, citric acid, phthalic acid, tetrahydrophthalic acid, 3-methyltetrahydrophthalic acid, 4-methyltetrahydrophthalic acid, 3-ethyltetrahydrophthalic acid, 4 -Ethyltetrahydrophthalic acid, hexahydrophthalic acid, 3-methylhexahydrophthalic acid, 4-methylhexahydrophthalic acid, 3-ethylhexahydrophthalic acid, 4-ethylhexahydrophthalic acid, methyltetrahydrophthalic acid, methylhexa Examples include hydrophthalic acid, endomethylenetetrahydrophthalic acid, methylendomethylenetetrahydrophthalic acid, trimellitic acid, pyromellitic acid, and diglycolic acid. Examples of polybasic acid anhydrides include these anhydrides. These compounds can be used alone or in combination of two or more.

  The polybasic acid or polybasic acid anhydride reacts with a hydroxyl group generated by the reaction of the above-described epoxy resin and a radically polymerizable unsaturated monocarboxylic acid, thereby giving the resin a free carboxyl group. The amount of the polybasic acid or polybasic acid anhydride to be reacted is 0.3 to 1.0 mol with respect to 1 mol of the hydroxyl group of the reaction product of the epoxy resin and the radically polymerizable unsaturated monocarboxylic acid. It is desirable that From the point that a highly sensitive resin film can be obtained at the time of exposure, the reaction is preferably carried out at a rate of 0.4 to 1.0 mol, more preferably 0.6 to 1.0 mol. When the amount is less than 0.3 mol, the dilute alkali developability of the obtained resin may be reduced. When the amount exceeds 1.0 mol, various properties (for example, water resistance) of the finally obtained cured coating film may be reduced. May decrease.

  The polybasic acid is preferably added to the unsaturated monocarboxylic oxide epoxy resin and subjected to a dehydration condensation reaction. The water produced during the reaction is preferably continuously removed from the reaction system, but the reaction is carried out in a heated state. Preferably, the reaction temperature is 70 to 130 ° C. When the reaction temperature exceeds 130 ° C., those bonded to an epoxy resin and radically polymerizable unsaturated groups of unreacted monomers may easily cause thermal polymerization, making synthesis difficult. The speed is slow, which may be undesirable in actual manufacturing.

  The acid value of the polybasic acid-modified unsaturated monocarboxylic acid epoxy resin, which is a reaction product of the polybasic acid or polybasic acid anhydride and the unsaturated monocarboxylic acid epoxy resin, is preferably 60 to 300 mgKOH / g. The acid value of the reaction product can be adjusted by the amount of the polybasic acid to be reacted.

  In the present invention, the polybasic acid-modified unsaturated monocarboxylic oxide epoxy resin can also be used as a photosensitive resin. However, one or more carboxyl groups in the polybasic acid-modified unsaturated monocarboxylic oxide epoxy resin have one or more. It is also preferable that a radically polymerizable unsaturated group is further introduced by reacting a radically polymerizable unsaturated group and a glycidyl compound having an epoxy group to further improve the photosensitivity.

  The photosensitive resin with improved photosensitivity has a photopolymerization reaction because the radical polymerizable unsaturated group is bonded to the side chain of the polymer skeleton of the precursor photosensitive resin by the reaction of the last glycidyl compound. It has high properties and can have excellent photosensitivity. Examples of the compound having one or more radically polymerizable unsaturated groups and an epoxy group include glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether, pentaerythritol triacrylate monoglycidyl ether, and the like. In addition, you may have multiple glycidyl groups in 1 molecule. These compounds may be used alone or in combination.

  The glycidyl compound is added to the polybasic acid-modified unsaturated monocarboxylic oxide epoxy resin solution and allowed to react. Usually, 0.05 to 0.5 mol of the carboxyl group introduced into the resin. React at a rate. In consideration of the photosensitivity (sensitivity) of the photosensitive resin composition containing the obtained photosensitive resin and the above-described electrical characteristics such as the thermal management width and electrical insulation, preferably 0.1 to 0.5. Preference is given to reacting in molar proportions. The reaction temperature is preferably 80 to 120 ° C. The photosensitive resin comprising the glycidyl compound-added polybasic acid-modified unsaturated monocarboxylic oxide epoxy resin thus obtained preferably has an acid value of 45 to 250 mgKOH / g.

  In the present invention, “(B) oxime photopolymerization initiator” means a photopolymerization initiator having an oxime group. The oxime photopolymerization initiator preferably has an aromatic group such as a substituted or unsubstituted phenyl group, and particularly preferably has a substituted or unsubstituted phenyl group. Also preferred are those in which a carbonyl group is present between an oxime group and an aromatic group (for example, a phenyl group).

  As the oxime photopolymerization initiator, those represented by the following chemical formulas (1) and (2) are particularly preferable.

In the formula, each symbol indicates the following.
n is 0 or 1.
R1 is any of the following groups.
(1) Aromatic groups such as phenyl groups (which are unsubstituted or substituted by one or more of alkyl groups having 1 to 6 carbon atoms, phenyl groups, halogens, OR8, SR9 and NR10R11. 2) C1-C20 alkyl group (3) C5-C8 cycloalkyl group (4) C2-C20 alkanoyl group (5) Benzoyl group (unsubstituted or C1-C1 Substituted with one or more of 6 alkyl groups, phenyl group, halogen, OR8, SR9, NR10R11)
(6) C2-C12 alkoxycarbonyl group (7) Phenoxycarbonyl group (unsubstituted or one or two of C1-C6 alkyl group, phenyl group, halogen, OR8, SR9, NR10R11) Substituted by more than species)
(8) -CONR10R11, CN, NO2, C1-C4 haloalkyl group, S (O) m- (C1-C6 alkyl group), unsubstituted or substituted with C1-C12 alkyl group S (O) m- (C6-C12 aryl group), or SO2O- (C1-C6 alkyl), SO2O- (C6-C10 aryl group), or diphenyl-phosphinoyl group (m = 1 or 2)

R2 is any of the following groups.
(1) C2-C12 alkanoyl group (unsubstituted or substituted by halogen or CN)
(2) C4-6 alkenoyl group (however, the double bond is not conjugated with the carbonyl group)
(3) Benzoyl group (unsubstituted or substituted with one or more of alkyl group having 1 to 6 carbon atoms, phenyl group, halogen, OR8, SR9, NR10R11)
(4) C2-C6 alkoxycarbonyl group (5) Phenoxycarbonyl group (which is unsubstituted or substituted by a C1-C6 alkyl group or halogen)

R3, R4, R5, R6 and R7 are each independently one of the following groups:
(1) hydrogen, halogen, alkyl group having 1 to 12 carbon atoms, cycloalkyl group having 5 to 8 carbon atoms (2) phenyl group (unsubstituted or alkyl group having 1 to 6 carbon atoms, phenyl group, Substituted with one or more of halogen, OR8, SR9, NR10R11)
(3) benzyl group, benzoyl group, alkanoyl group having 2 to 12 carbon atoms, or alkoxycarbonyl group having 2 to 12 carbon atoms (4) thiophenyl group (5) phenonoxycarbonyl group, OR8, SR9, SOR9, SO2R9 or NR10R11 (Wherein the substituents OR8, SR9 and NR10R11 are optionally 5 or 6-membered rings via a further substituent of the phenyl ring or one of the carbon atoms of the phenyl ring and the group R8, R9, R10 and / or R11). Form)

In the above, R8 is any of the following groups.
(1) hydrogen, alkyl group having 1 to 12 carbon atoms (2) alkyl group having 2 to 6 carbon atoms (—OH, —SH, —CN, C1 to C4 alkoxy, C3 to C6 alkeneoxy, —OCH 2 CH 2 CN, —OCH 2 CH 2 (CO) O (C1-C4 alkyl), -O (CO)-(C1-C4 alkyl), -O (CO) -phenyl,-(CO) OH or-(CO) O (C1-C4 alkyl) Has been replaced)
(3) C2-C6 alkyl group (interrupted by -O-)
(4)-(CH2CH2O) nH, C2-8 alkanoyl group, C3-12 alkenyl group, C3-6 alkenoyl group, C5-7 cycloalkyl group, phenyl group (non- Substituted or substituted by halogen, an alkyl group having 1 to 12 carbon atoms or an alkoxy group having 1 to 4 carbon atoms) (n = 1-20)

R9 is any of the following groups.
(1) C1-C12 alkyl group (2) C3-C12 alkenyl group (3) C5-C8 cycloalkyl group (4) C2-C6 alkyl group (-OH,- SH, -CN, C1-C4 alkoxy group, C3-C6 alkeneoxy group, -OCH2CH2CN, -OCH2CH2 (CO) O (C1-C4 alkyl), -O (CO)-(C1-C4 Alkyl), -O (CO) -phenyl,-(CO) OH or-(CO) O (C1-C4 alkyl))
(5) C2-C12 alkyl group (interrupted by -O- or -S-)
(6) Phenyl group (which is unsubstituted or substituted by halogen, an alkyl group having 1 to 12 carbon atoms or an alkoxy group having 1 to 4 carbon atoms)
(7) Phenyl group- (C1-C3 alkyl group),

R10 and R11 are each independently one of the following groups.
(1) hydrogen, alkyl group having 1 to 12 carbon atoms, hydroxyalkyl group having 2 to 4 carbon atoms, alkoxyalkyl group having 2 to 10 carbon atoms, alkenyl group having 3 to 5 carbon atoms, cyclohexane having 5 to 12 carbon atoms Alkyl group, phenyl group- (C1-C3 alkyl)
(2) Phenyl group (which is unsubstituted or substituted by an alkyl group having 1 to 12 carbon atoms or an alkoxy group having 1 to 4 carbon atoms)
(3) C2-C3 alkanoyl group, C3-C6 alkenoyl group, benzoyl (4) R10 and R11 together form a C2-C6 alkylene group.
(5) R10 and R11 together form an alkylene group having 2 to 6 carbon atoms (interrupted by -O- or -NR8-).
(6) R10 and R11 together form an alkylene group having 2 to 6 carbon atoms (substituted with hydroxyl, C1-C4 alkoxy, C2-C4 alkanoyloxy or benzoyloxy).
M is alkylene having 1 to 12 carbon atoms, cyclohexylene, phenylene,-(CO) O- (C2-C12 alkylene) -O (CO)-,-(CO) O- (CH2CH2O) n- (CO)- Or-(CO)-(C2-C12 alkylene)-(CO)-(n = 1-20).

  Specific examples of the oxime photopolymerization initiator include “IRUGACURE OXE01” and “CGI-325” (manufactured by Ciba Specialty Chemicals). The main component of “IRUGACURE OXE01” is 1,2-octanedione, 1- [4- (phenylthio) -2- (O-benzoyloxime)] (see the following formula). Here, R1 is a hexyl group, R2 is a benzoyl group, R3, R4, R6, and R7 are hydrogen atoms, and R5 is a thiophenyl group.

  (B) It is preferable that an oxime system photoinitiator is normally added in the ratio of 0.2-30 weight part with respect to 100 weight part of photosensitive resin of the said (A) component. When the amount of (B) is too small, the photocuring reaction of the photosensitive resin is difficult to proceed. If the amount of addition of (B) is too large, the effect is not improved for the increase of the amount added, but rather it is economically disadvantageous or the mechanical properties of the cured coating film may be reduced.

  By using an oxime photoinitiator, compared to the case of using a normal photopolymerization initiator, the sensitivity to the active energy rays irradiated during exposure is improved, and the photopolymerization rate of the photosensitive resin. As a result, high sensitivity and high resolution can be obtained. Further, the mist is not generated during manufacturing.

  In the photosensitive resin composition of the present invention, in addition to the (B) oxime photoinitiator, other photopolymerization initiator (H) can be used in combination. Moreover, by mixing and using (C) diluent and (D) thermosetting compound, it can be conveniently used, for example as a soldering resist composition for printed wiring board manufacture.

  The photopolymerization initiator (H) used in combination is not particularly limited, and any conventionally known photopolymerization initiator (H) can be used. Specific examples include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylaminoacetophenone, 2,2-dimethoxy-2-phenylacetophenone. 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1- [4- (methylthio) phenyl] 2-morpholino-propan-1-one, 4- (2-hydroxyethoxy) phenyl-2- (hydroxy-2-propyl) ketone, benzophenone, p-phenylbenzophenone, 4,4'-diethyla Nobenzophenone, dichlorobenzophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tertiarybutylanthraquinone, 2-aminoanthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone 2,4 diethylthioxanthone, benzyl dimethyl ketal, acetophenone dimethyl ketal, P-dimethylaminobenzoic acid ethyl ester and the like. These can be used alone or in combination.

  When a photopolymerization initiator (H) other than (B) is used in combination, the amount of photopolymerization initiator used (B) and the total amount) is 100 parts by weight of the photosensitive resin (A). 0.2 to 30 parts by weight is preferable. When this amount is too small, the photocuring reaction of the photosensitive resin is difficult to proceed. If this amount is too large, the effect is not improved with respect to the increase in the amount added, but it may be economically disadvantageous or the mechanical properties of the cured coating film may be deteriorated. From the viewpoint of photocurability, economy, mechanical properties of the cured coating film, etc., the amount used (total value) is preferably 1 to 15 parts by weight.

  (C) A diluent consists of at least 1 sort (s) of a photopolymerizable monomer and an organic solvent. The photopolymerizable monomer is also referred to as a reactive diluent, which further enhances the photocuring of the photosensitive resin as the component (A) to obtain a coating film having acid resistance, heat resistance, alkali resistance, and the like. It is intended for use. As the reactive diluent, a compound having at least two double bonds in one molecule is preferably used. An organic solvent that is a non-reactive diluent may be used to adjust the viscosity and drying properties of the composition containing the photosensitive resin as the component (A). May be. In addition, when the photocurability of only the photosensitive resin (A) is sufficient, a photopolymerizable monomer may not be used.

  Typical examples of the photopolymerizable monomer (reactive diluent) include 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di ( (Meth) acrylate, polyethylene glycol di (meth) acrylate, neopentyl glycol adipate di (meth) acrylate, hydroxypivalate neopentyl glycol di (meth) acrylate, dicyclopentanyl di (meth) acrylate, caprolactone modified dicyclopentenyl di (Meth) acrylate, ethylene oxide-modified phosphoric acid di (meth) acrylate, allylated cyclohexyl di (meth) acrylate, isocyanurate di (meth) acrylate, trimethylolpropane tri (meth) acrylate, dipe Taerythritol tri (meth) acrylate, propionic acid modified dipentaerythritol tri (meth) acrylate, pentaerythritol tri (meth) acrylate, propylene oxide modified trimethylolpropane tri (meth) acrylate, tris (acryloxyethyl) isocyanurate, propion Examples include reactive diluents such as acid-modified dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and caprolactone-modified dipentaerythritol hexa (meth) acrylate.

  The above-mentioned 2-6 functional and other polyfunctional reactive diluents can be used in either a single product or a plurality of mixed systems. The addition amount of the reactive diluent is preferably 2.0 to 40 parts by weight with respect to 100 parts by weight of the photosensitive resin. If the amount added is too small, sufficient photocuring cannot be obtained, and sufficient characteristics such as acid resistance of the cured coating film cannot be obtained. Adhesion to the surface is likely to occur, making it difficult to obtain the desired cured coating film. The amount of reactive diluent added is 100 parts by weight of the photosensitive resin (A) in terms of photocurability, physical properties such as acid resistance and heat resistance of the cured coating film, and prevention of adhesion of the artwork film to the substrate. On the other hand, it is more preferably 4.0 to 30 parts by weight.

  Examples of the organic solvent include ketones such as methyl ethyl ketone and cyclohexanone, aromatic hydrocarbons such as toluene and xylene, alcohols such as methanol, isopropanol and cyclohexanol, and alicyclic carbonization such as cyclohexane and methylcyclohexane. Petroleum solvents such as hydrogen, petroleum ether and petroleum naphtha, cellosolves such as cellosolve and butylcellosolve, carbitols such as carbitol and butylcarbitol, ethyl acetate, butyl acetate, cellosolve acetate, butyl cellosolve acetate, carbitol acetate And acetates such as butyl carbitol acetate. When using an organic solvent, it is preferable that the usage-amount is 40-500 weight part with respect to 100 weight part of photosensitive resin (A).

  “(D) Thermosetting compound” is a sufficiently strong coating film (coating strength, heat resistance, post-curing after exposure and development of the coating film in the photosensitive resin composition of the present invention. Durability, chemical resistance, environmental resistance, etc.). Examples of (D) include an epoxy thermosetting compound and other thermosetting compounds, and it is preferable that at least an epoxy thermosetting compound is contained in the photosensitive resin composition.

  A typical example of the epoxy thermosetting compound is an epoxy resin (including an epoxy oligomer) having at least one epoxy group, preferably two or more epoxy groups in one molecule. Not limited to. For example, a bisphenol A type epoxy resin obtained by reacting bisphenol A and epichlorohydrin in the presence of an alkali, an epoxidized product of a resin obtained by condensation reaction of bisphenol A and formalin, Instead, those using brominated bisphenol A, novolak type epoxy resins obtained by reacting novolak resin with epichlorohydrin to glycidyl ether (phenol novolak type epoxy resin, o-cresol novolak type epoxy resin, p-tert-butylphenol novolak type, etc. ), Bisphenol F-type and bisphenol S-type epoxy resins obtained by reacting bisphenol F and bisphenol S with epichlorohydrin, cyclohexene oxide groups, tricyclode Such as cycloaliphatic epoxy resins having thiol oxide groups, cyclopentene oxide groups, diglycidyl phthalate, diglycidyl tetrahydrophthalate, diglycidyl hexahydrophthalate, diglycidyl-p-hydroxybenzoic acid, glycidyl dimer, etc. Glycidyl ester resins, tetraglycidyl diaminodiphenylmethane, glycidylamine resins such as triglycidyl-p-aminophenol, (propylene, polypropylene) glycol diglycidyl ether, polytetramethylene glycol diglycidyl ether, glycerol polyglycidyl ether, trimethylolpropane poly Glycidyl ether, resorcin diglycidyl ether, 1,6 hexanediol diglycidyl ether, , Propylene) glycol diglycidyl ether, sorbitol polyglycidyl ether, sorbitan polyglycidyl ether, glycidyl ether resins such as pentaerythritol polyglycidyl ether, tris (2,3-epoxypropyl) isocyanurate, triglycidyl tris (2-hydroxyethyl) ) Triglycidyl isocyanurate having a triazine ring such as isocyanurate, dicyclopentadiene type epoxy resin and the like. A thermosetting compound (D) may be used independently and may be used together.

  (D) Epoxy thermosetting compound used alone or in combination with other thermosetting compounds) is in a ratio of 5 to 100 parts by weight with respect to 100 parts by weight of the photosensitive resin of component (A). It is preferable to be added. After the post-cure after the addition amount is too small, a coating film having desired physical properties may not be obtained, and when it is too much, the photocurability of the component (A) may be lowered. From the viewpoint of the physical properties of the coating film after post-curing and the photocurability of the component (A), the amount of the thermosetting compound added is more preferably 10 to 70 parts by weight.

  In addition to the above components (A) to (D), (I) a curing agent for epoxy resins can also be used. The curing agent includes at least one organic acid salt of dicyandiamide and an organic acid salt of N-substituted dicyandiamide as a derivative thereof. Examples of the substituent of the N-substituted dicyandiamide include linear and branched alkyl groups having 1 to 12 carbon atoms, allyl groups which may have a nuclear substituent such as alkyl groups, alkyls, and the like, and organic acids. Examples thereof include organic carboxylic acid, organic phosphoric acid, and organic sulfuric acid. These compounds may be used in combination of at least two (two or more), and are preferably selected in the range of 0.1 to 10 parts by weight per 100 parts by weight of the component (A). If this content is too small, the thermosetting properties may not be sufficiently exhibited, and if it is too much, the pot life of the photosensitive resin composition of the present invention tends to be shortened, and the characteristics of the solder resist film of the coating film deteriorate. It can be a cause. Considering the thermosetting characteristics, the pot life of the composition, the characteristics of the solder resist film, etc., the content of the above compound as a curing agent is more preferably in the range of 1 to 8 parts by weight.

  Other curing agents include dicyandiamide derivatives such as N-substituted dicyandiamide having the above substituents, dicyandiamide, boron trifluoride-amine complex, organic acid hydrazide, diaminomaleonitrile (DAMN) and its derivatives, melamine and its Derivatives, guanamine and its derivatives, amine imide (AI), polyamine salts, azoles, phenol compounds and the like.

  “(E) Mercaptopropionic acid or a derivative thereof” means a derivative such as mercaptopropionic acid or an ester, amide, or acid anhydride thereof. (E) is particularly preferably represented by the following formula.

  In the above formula, R12 is hydrogen (H) or an alkyl group having 1 to 13 carbon atoms.

  R13 is an alkyl group having 1 to 3 carbon atoms such as CH2 and C2H5. R14 is a hydroxyl group or an alkyl group having 1 to 3 carbon atoms. m is 1-4.

  Specific examples of (E) include 3-mercaptopropionic acid (3-MPA, BMPA), methoxybutyl mercaptopropionate, octyl mercaptopropionate (BMPA-2EH), tridecyl mercaptopropionate, trimethylolpropane tristhiopropionate. (TMTP), pentaerythritol tetrakisthiopropionate (PETP) and the like can be mentioned, and these can be used alone or in combination of two or more. Particularly preferred is trimethylolpropane tristhiopropionate (TMTP) from the viewpoint of improving developability in a dilute aqueous alkali solution after preliminary drying.

  (E) By using mercaptopropionic acid or a derivative thereof, it is possible to improve a reduction in the removability of the oxime photoinitiator by a dilute alkali developer. Also, oxygen exposure is removed by light irradiation in the atmosphere during exposure. Usually, in the presence of oxygen, peroxy radicals are generated, and there is a problem of suppressing the curing of oxygen, which inhibits the photopolymerization of the photosensitive resin. By using mercaptopropionic acid derivatives, peroxy radicals react with mercaptans to form thiyl radicals, eliminating the influence of oxygen during curing.

  The (E) mercaptopropionic acid derivative is preferably added at a ratio of 15 to 70 parts by weight with respect to 100 parts by weight of the (B) oxime photoinitiator.

  “(F) Monofunctional methacrylate antioxidant” means an antioxidant having one methacrylate group as a polymerizable group. Such antioxidants are known. Moreover, what is represented by a following formula is especially preferable.

  R16 is preferably a pentamethylpiperidyl group or a tetramethylpiperidyl group. Further, “(F) monofunctional methacrylate antioxidant” is specifically preferably pentamethylpiperidyl methacrylate or tetramethylpiperidyl methacrylate. These monofunctional methacrylate antioxidants can be used alone or in combination of two or more. Particularly preferred is tetramethylpiperidyl methacrylate from the viewpoint of improving the standing life after preliminary drying. Particularly preferred compound formulas are shown below.

  The monofunctional methacrylate antioxidant is extremely effective for suppressing copper foil oxidation by the mercaptopropionic acid derivative, but tends to shorten the standing life of the coating film after preliminary drying. For this reason, when (G) a benzothiazole-based corrosion inhibitor is used in combination, it is possible to prolong the life of the coating film after preliminary drying while suppressing the copper foil oxidation by the mercaptopropionic acid derivative.

  (G) A benzothiazole-based corrosion inhibitor is a compound having a benzothiazole skeleton, and is preferably represented by the following formula.

In the formula, p is 0 or 1. R17 is _{hydrogen, (CH 2) n COOH (n} = 0~4). Specific examples include (1,3-benzothiazol-2-ylthio) succinic acid (the following formula).

  In addition to the above components (A) to (I), the photosensitive resin composition of the present invention may contain various additives as necessary, for example, inorganic pigments such as silica, alumina, talc, calcium carbonate, barium sulfate and the like. Ingredients, phthalocyanine green, phthalocyanine-based organic pigments such as phthalocyanine blue, azo-based organic pigments, inorganic pigments such as titanium dioxide, and other known color pigments, antifoaming agents, leveling agents, and other paint additives be able to.

  The above (A) to (I) and other components are mixed as necessary, and if necessary, by a kneading means such as a three-roll, ball mill or sand mill, or a stirring means such as a super mixer or a planetary mixer. The photosensitive resin composition of the present invention is obtained by kneading or mixing.

  The photosensitive resin composition of the present invention obtained as described above has a desired thickness, for example, 5 to 100 μm, on a printed wiring board having a circuit pattern formed by etching a copper foil of a copper-clad laminate, for example. It is applied with a thickness of. As a coating means, full-scale printing by the screen printing method is generally used at present, but any means may be used as long as it can be applied uniformly including this. For example, spray coaters, phone melt coaters, bar coaters, applicators, blade coaters, knife coaters, air knife coaters, curtain flow coaters, roll coaters, gravure coaters, offset printing, dip coaters, brush coating, and other ordinary methods can be used.

  After coating, pre-baking is performed in a hot air furnace or a far-infrared furnace as necessary, that is, temporary drying is performed to bring the surface of the coating film into a tack-free state. The prebaking temperature is preferably about 50 to 100 ° C.

Next, exposure by laser direct drawing using LDI (Laser Direct imaging) is performed. Alternatively, exposure with active energy rays is performed using a negative mask that prevents the passage of active energy rays. As the negative mask, a negative film is used when the active energy ray is ultraviolet, a metal mask is used when it is an electron beam, and a lead mask is used when it is an X-ray, but it can be printed because a simple negative film can be used. In the production of wiring boards, ultraviolet rays are often used as active energy rays. The irradiation amount of ultraviolet rays is approximately 10 to 1000 mJ / cm ² .

  In the case of manufacturing a printed wiring board, for example, except for the soldering land of the circuit pattern, the light-transmitting pattern negative film is brought into close contact, and ultraviolet light is irradiated from above. The coating film is developed by removing the non-exposed areas corresponding to the lands with a dilute alkaline aqueous solution. This removal may be any of dissolution, swelling, peeling, etc. of the unexposed part. The dilute alkaline aqueous solution used at this time is generally 0.5 to 5% sodium carbonate aqueous solution, but other alkalis can also be used.

  Next, when a thermosetting compound is contained, it is post-cured by heating, for example, for 20 to 80 minutes in a dryer such as a hot air oven or a far-infrared oven at 130 to 170 ° C. Thus, a solder resist film can be formed.

  In this way, a printed wiring board coated with a solder resist film is obtained, on which electronic components are connected, fixed and mounted by soldering by a jet soldering method or a reflow soldering method. A circuit unit is formed.

  In the present invention, the printed wiring board coated with the solder resist film before mounting the electronic component and the printed wiring board mounted with the electronic component mounted on the printed wiring board are included in the object.

Example 1
(Preparation of solder resist composition)
Each component was mixed by weight (unit gram) as shown in Table 1 to prepare a composition. Detailed component amounts are shown below.
(A) Photosensitive resin, UE-EXP-2110 (Dainippon Ink Chemical Co., Ltd.) 37.5 g
(B) Oxime-based photoinitiator, IRGACURE OXE01 (Ciba Specialty Chemicals) 1.0 g,
(H) Non-oxime photoinitiator, BCIM (Hodogaya Chemical Co., Ltd.) 0.45 g,
(H) Non-oxime photoinitiator, EDB (made by Nippon Sebel Hegner) 0.75 g,
(C) Diluent, Aronix M-400 (Toagosei Co., Ltd.) 2.5 g, A-TMPt-9EO (Shin Nakamura Chemical Co., Ltd.) 2.5 g,
(D) thermosetting compound, Epicoat YL-6121H (manufactured by Japan Epoxy Resin Co., Ltd.) 5.0 g,
GTR-1800 (Nippon Kayaku Co., Ltd.) 5.0 g,
(E) Mercaptopropionic acid derivative, trimethylolpropane tristhiopropionate (manufactured by Sakai Chemical Co., Ltd.) 0.15 g
(F) Monofunctional methacrylate antioxidant, FA-712HM (manufactured by Hitachi Chemical Co., Ltd.) 0.4 g
(G) benzothiazole-based corrosion inhibitor, IRGACOR 252LD (manufactured by Ciba Specialty Chemicals) 1.0 g
Colored pigment, Lionol Blue FG-7351 (manufactured by Toyo Ink Co., Ltd.) 0.2g
Antifoam, KS-66 (Shin-Etsu Silicone) 0.9g
Thixox, AEROSIL R-97 (Japan Aerosil 4) 1.4g
CO-01 (made by Showa Polymer Co., Ltd.) 3.8 g
Daiso Dup A (Daiso Co., Ltd.) 1.25g
DICY-7 (Japan Epoxy Resin) 0.2g
Arcosolve DPM (Kyowa Hakko Kogyo Co., Ltd.) 1.25g
EDGAC (Daicel Chemical Industries) 7.7g
Solvesso 150 (ExxonMobil Corp.) 7.7g
Talc 1.1g
Barium sulfate 21.0g
Melamine 1.0g

  This blend was mixed and dispersed with three rolls to prepare a photosensitive resin composition. Table 2 shows the results of evaluating the sensitivity, tack, thermal management width, shelf life, and postcuring coating performance of this composition by the methods described below.

(Example 2)
A photosensitive resin composition was prepared in the same manner as in Example 1, except that the amount of (E) mercaptopropionic acid derivative and trimethylolpropane tristhiopropionate (manufactured by Sakai Chemical Co., Ltd.) was 0.3 g. Table 2 shows the results of evaluating the sensitivity, tack, thermal management width, shelf life, and postcuring coating performance of this composition by the methods described below.

(Example 3)
A photosensitive resin composition was prepared in the same manner as in Example 1, except that the amount of (G) benzothiazole-based corrosion inhibitor “IRGACOR 252LD” (manufactured by Ciba Specialty Chemicals) was 2.0 g. Table 2 shows the results of evaluating the sensitivity, tack, thermal management width, shelf life, and postcuring coating performance of this composition by the methods described below.

Example 4
In Example 1, the amount of (E) mercaptopropionic acid derivative and trimethylolpropane tristhiopropionate (manufactured by Sakai Chemical Co., Ltd.) was 0.15 g, (F) monofunctional methacrylate antioxidant, (G) benzothiazole No system corrosion inhibitor was added. A photosensitive resin composition was prepared in the same manner except for this. Table 2 shows the results of evaluating the sensitivity, tack, thermal management width, shelf life, and postcuring coating performance of this composition by the methods described below.

(Example 5)
In Example 1, 0.15 g of (E) mercaptopropionic acid derivative and trimethylolpropane tristhiopropionate (manufactured by Sakai Chemical Co., Ltd.), (F) monofunctional methacrylate antioxidant, FA-712HM (Hitachi Chemical) The amount of (made by Kogyo Co., Ltd.) was 0.4 g, and (G) was not added. A photosensitive resin composition was prepared in the same manner except for this. Table 1 shows the results of evaluating the sensitivity of the coating film of this composition, tack, thermal management width, standing life, and coating performance after post-curing by the methods described below.

(Example 6)
In Example 1, 0.15 g of (E) mercaptopropionic acid derivative, trimethylolpropane tristhiopropionate (manufactured by Sakai Chemical Co., Ltd.), (G) benzothiazole-based corrosion inhibitor, IRGACOR 252LD (Ciba Specialty Chemicals) (F) monofunctional methacrylate antioxidant was not added. Table 1 shows the results of evaluating the sensitivity of the coating film of this composition, tack, thermal management width, standing life, and coating performance after post-curing by the methods described below.

(Comparative Example 1)
In Example 1, (E) mercaptopropionic acid derivative, trimethylolpropane tristhiopropionate (manufactured by Sakai Chemical Co., Ltd.), (F) monofunctional methacrylate antioxidant, FA-712HM (manufactured by Hitachi Chemical Co., Ltd.), ( G) A photosensitive resin composition was prepared in the same manner except that the amount of the benzothiazole-based corrosion inhibitor, IRGACOR 252LD (manufactured by Ciba Specialty Chemicals) was 0 g. Table 2 shows the results of evaluating the sensitivity, tack, thermal management width, shelf life, and postcuring coating performance of this composition by the methods described below.

(Comparative Example 2)
In Comparative Example 1, 0.4 g of (F) monofunctional methacrylate antioxidant, FA-712HM (manufactured by Hitachi Chemical Co., Ltd.), (G) benzothiazole corrosion inhibitor, IRGACOR 252LD (manufactured by Ciba Specialty Chemicals) A photosensitive resin composition was prepared in the same manner except that the amount of) was 1.0 g. Table 2 shows the results of evaluating the sensitivity, tack, thermal management width, shelf life, and postcuring coating performance of this composition by the methods described below.

  Evaluation of coating film sensitivity (tack, thermal management width, shelf life, and post-curing coating film performance (acid resistance, plating resistance, heat resistance, copper foil oxidation) of the photosensitive resin composition obtained above The method is as follows.

(I) Sensitivity The photosensitive resin composition of each of the above examples was applied to a thickness of 35 μm (before drying) by screen printing using a 21-step step tablet as a test plate, and dried to dry each coated substrate. We were ^prepared, subjected to ultraviolet exposure in two different dose of 30mJ / cm 2, 530mJ / cm 2, using a 1 wt% aqueous solution of sodium carbonate, 0.2 MPa. Development was performed at a spray pressure of s for 60 seconds, and evaluation was performed with the maximum number of steps at which the coating film remained completely. The larger the number of steps, the better the photosensitive characteristics.

(II) Tuck (Dry to touch)
The photosensitive resin composition of each of the above examples was applied to the entire surface of the substrate with the copper foil on which the circuit pattern was formed, dried at 70 ° C. for 50 minutes, the negative film was adhered onto the coating film, and after exposure, The state of sticking marks on the negative film was visually observed and judged according to the following criteria.
○: There is no negative film sticking mark on the coating film surface. Δ: There is a slight negative film sticking mark on the coating film surface. X: There is a negative film sticking mark on the entire coating film surface.

(III) Thermal management width
Each photosensitive resin composition in each of the above examples was applied to the entire surface of a circuit board-formed copper foil substrate, and the drying time was extended to 70 minutes at intervals of 10 minutes. % Sodium carbonate aqueous solution and 0.2 MPa. Development was performed at a spray pressure of s for 60 seconds, and the longest drying time (min) at which the coated film could be completely removed was measured.

(IV) Leaving life Each photosensitive resin composition of each of the above examples was applied to the entire surface of a circuit board-formed copper foil substrate, and the substrate dried at 70 ° C. for 50 minutes was allowed to stand. Using an aqueous sodium carbonate solution of 0.2 MPa. Development was performed at a spray pressure of s for 60 seconds, and a standing time during which the coated film was completely removed was measured. The longer the time, the better the standing life.

(V) Coating film performance The substrate (copper-clad laminate) that had been surface-treated in advance was coated with the photosensitive resin composition of each of the above examples to a thickness of 35 μm (before drying) by screen printing. A coated substrate was prepared, and each coated substrate was pre-dried at 70 ° C. for 50 minutes. A negative film was brought into close contact with this substrate, exposed by irradiating with ultraviolet rays at an exposure amount of 50 mJ / cm ² , and then developed with a 1% by mass aqueous sodium carbonate solution for 60 seconds to form a pattern. Next, this substrate was thermally cured at 150 ° C. for 60 minutes to prepare a test piece having a cured coating film, and the following coating film performance was evaluated.

(I) Acid resistance A coated substrate having a cured coating film is immersed in 10% hydrochloric acid at room temperature for 30 minutes, washed with water, then subjected to a peeling test using a cellophane adhesive tape, and observed for peeling and discoloration of the coating film. Evaluated.
○: No change at all △: Only a slight change ×: Significant change

(Ii) Plating resistance A coated substrate having a cured coating film was subjected to gold plating and then subjected to a peeling test using a cellophane adhesive tape. The resist layer was peeled off and discolored and evaluated according to the following criteria.
○: No change at all △: Only a slight change ×: Significant change

(Iii) Heat resistance A coated substrate having a cured coating film is immersed in a solder bath at 260 ° C. for 30 seconds after applying a substrate coated with ULF-210R (Tamla Kaken Co., Ltd.) according to the test method of JIS C 6481, and then cellophane. A peeling test with an adhesive tape (trade name) was defined as one cycle, and the coating state after a total of 1 to 3 cycles was visually evaluated according to the following criteria.
○: No change in coating film even after 3 cycles Δ: Change after 2 cycles ×: Separation after 1 cycle

(Iv) Copper foil oxidizability The degree of discoloration of the copper foil of the substrate that had been thermally cured at 150 ° C. for 60 minutes was visually observed and evaluated according to the following criteria.
○: No discoloration Δ: Slightly discolored ×: Remarkably discolored

  From the results in Table 2, the compositions of Examples 1, 2, and 3 are excellent in terms of sensitivity, thermal management width, standing life, plating resistance, acid resistance, and prevention of copper foil oxidation.

  In the composition of Example 4, (E) a mercaptopropionic acid derivative is added, and (F) a monofunctional methacrylate-based antioxidant and (G) a benzothiazole-based corrosion inhibitor are not added. Although sensitivity, thermal management width, standing life, plating resistance, and acid resistance are excellent, copper foil oxidation occurs by using (E).

  In the composition of Example 5, (E) a mercaptopropionic acid derivative, (F) a monofunctional methacrylate-based antioxidant is added, and (G) a benzothiazole-based corrosion inhibitor is not added. Sensitivity, thermal management width, plating resistance and acid resistance are excellent, and copper foil oxidation does not occur. However, neglected life was slightly shortened by using (F).

  In the composition of Example 6, (E) a mercaptopropionic acid derivative, (G) a benzothiazole-based corrosion inhibitor is added, and (F) a monofunctional methacrylate-based antioxidant is not added. It has excellent sensitivity, thermal management width, plating resistance, and acid resistance, and has a long shelf life. However, copper foil oxidation slightly occurs because (F) and (G) are not used together.

Since Comparative Example 1 does not use (E), (F), or (G), the developability with a dilute alkaline aqueous solution is lowered and the thermal management width is adversely affected. The neglected life is short.
Since Comparative Example 2 does not use (E) a mercaptopropionic acid derivative, (G) the use of a benzothiazole-based corrosion inhibitor reduces the developability in a dilute alkaline aqueous solution and adversely affects the thermal management range. .

Claims (4)

  (A) an active energy ray-curable resin having at least two ethylenically unsaturated bonds in one molecule, (B) an oxime-based photopolymerization initiator, (C) a diluent, (D) a thermosetting compound, and (E) A photosensitive resin composition comprising mercaptopropionic acid or a derivative thereof.   The photosensitive resin composition according to claim 1, further comprising (F) a monofunctional methacrylate antioxidant.   The photosensitive resin composition according to claim 1, further comprising (G) a benzothiazole-based corrosion inhibitor.   It has a cured film of the photosensitive resin composition as described in any one of Claims 1-3, The printed wiring board before or after mounting electronic components.