JP7216483B2 - Curable resin composition, dry film, cured product and printed wiring board - Google Patents

Description

The present invention relates to a curable resin composition, dry film, cured product and printed wiring board.

Conventionally, as materials for forming permanent films such as solder resists, interlayer insulating layers, and coverlays for printed wiring boards, Patent Document 1 discloses a carboxyl group-containing polyurethane and a polyfunctional polyurethane having a total chlorine content of less than 0.7% by mass. A thermosetting resin composition containing an aliphatic glycidyl ether compound is disclosed.

In recent years, with the rapid progress of semiconductor parts, electronic devices tend to be lighter, thinner, shorter, and more sophisticated, and have more functions. Following this trend, miniaturization and multi-pin semiconductor packages have been put to practical use.
Specifically, instead of IC packages called QFP (quad flat pack package), SOP (small outline package), etc., BGA (ball grid array), CSP (chip scale package), etc. An IC package called is used. In recent years, FC-BGA (Flip Chip Ball Grid Array) has also been put to practical use as an IC package with a higher density.
In printed wiring boards (also called package substrates) used for such IC packages, SROs (Solder Resist Openings) have a narrow pitch and are formed close to each other, so short circuits and crosstalk noise occur between SROs. more likely to fall. In addition, the solder resist formed between the SROs becomes thin and thin, so cracks are likely to occur. Therefore, permanent films such as solder resists used for package substrates are required to have high long-term reliability, specifically high insulation reliability. In particular, the demand for reliability is expected to further increase as the density of package substrates increases in the future.
In recent years, the reliability of the thermosetting resin composition described in Patent Literature 1 has become insufficient.

In order to meet such reliability requirements, Patent Document 2 discloses a curable resin composition containing a carboxyl group-containing resin and an epoxy resin having a silsesquioxane skeleton.

Patent No. 5167113 WO2017/170959

The curable resin composition described in Patent Literature 2 is excellent in reliability, but there is still room for improvement as there is a constant demand for improved reliability. In addition, there is a high demand for insulation reliability under high voltage for automotive applications, and the HAST test under high voltage, that is, the B-HAST test accelerates the decomposition of the silsesquioxane skeleton compared to general-purpose resin skeletons. There was room for improvement.

Accordingly, an object of the present invention is to provide a curable resin composition capable of obtaining a cured product having excellent reliability, particularly excellent insulation reliability under high voltage loading, and a resin layer obtained from the composition. , a cured product of the composition or the resin layer of the dry film, and a printed wiring board having the cured product.

As a result of extensive research and development on a curable resin composition that can further improve reliability, the present inventors have found that by using an epoxy resin having a specific epoxy equivalent, it is possible to achieve high reliability even when a voltage is applied. The inventors have found that a cured product can be obtained, and have completed the present invention.

The curable resin composition of the present invention contains (A) a carboxyl group-containing resin, (B) a photopolymerization initiator, (C) an epoxy resin having an epoxy equivalent of 130 or less, and (D) an inorganic filler. It is characterized by

In the curable resin composition of the present invention, the (C) epoxy resin preferably has an epoxy equivalent of 100 or less, and the (D) inorganic filler is preferably surface-treated. (D) The mixing ratio of the inorganic filler is preferably 25 to 85% by mass.

The dry film of the present invention is characterized by having a resin layer obtained by coating the curable resin composition on a film and drying the composition.
Moreover, the cured product of the present invention is characterized by being obtained by curing the resin layer of the curable resin composition or the dry film.
Furthermore, the printed wiring board of the present invention is characterized by having the cured product.

ADVANTAGE OF THE INVENTION According to this invention, the hardened|cured material excellent in the insulation reliability in the state where a high voltage is loaded can be obtained.

The curable resin composition of the present invention contains (A) a carboxyl group-containing resin, (B) a photopolymerization initiator, (C) an epoxy resin having an epoxy equivalent of 130 or less, and (D) an inorganic filler. It is something to do.

Since the curable resin composition of the present invention contains a carboxyl group-containing resin and an epoxy resin having an epoxy equivalent of 130 or less, the obtained cured product has a high glass transition temperature (Tg) and a linear expansion coefficient (CTEα1, Not only is α2) low, but the storage modulus (E) at high temperatures is high. Therefore, the fluidity of the cured product is suppressed at high temperatures, the generated stress is reduced, and the heat resistance is excellent. In other words, it can be said that the cured product of the present invention has a high crosslink density and hardly changes in physical properties at high temperatures.
Furthermore, since the curable resin composition of the present invention contains a carboxyl group-containing resin and an epoxy resin having an epoxy equivalent of 130 or less, many of them have fluidity at room temperature, and the curability (reaction rate) at low temperatures is improved. In addition, oxidation of the copper circuit due to high-temperature treatment can be suppressed, and adhesion between the cured product and the printed wiring board can be maintained.
In addition, the cured product of the present invention has a high storage elastic modulus at high temperatures, so it is thought that the crosslink density is high and the water absorption is low.
Furthermore, since the curable resin composition of the present invention contains an epoxy resin having an epoxy equivalent of 130 or less, it is possible to obtain a cured product with a high crosslink density. A cured product having high resistance to cracking can be obtained.
Specific examples of epoxy resins having an epoxy equivalent of 130 or less will be described later, but conventional epoxy resins having a silsesquioxane skeleton are not included. Epoxy resins having a silsesquioxane skeleton have Si—O bonds derived from the silsesquioxane skeleton. It was found that the insulation reliability at high voltage is not sufficient because it is vulnerable to basicity. On the other hand, the epoxy resin of the present invention having an epoxy equivalent of 130 or less does not have a Si—O bond and has a bond that does not decompose at the cathode, and has excellent insulation reliability at high voltage. ing.
By using an epoxy resin having an epoxy equivalent of 130 or less to achieve such a high crosslinking density, heat resistance, low-temperature curability, and low water absorption can be imparted, and the cured product of the curable resin composition of the present invention can be obtained. is considered to be excellent in crack resistance and insulation reliability at high voltage.
Moreover, according to the curable resin composition of the present invention, a cured product having excellent resolution can be obtained.

Each component of the curable resin composition of the present invention is described below. In this specification, (meth)acrylate is a generic term for acrylate, methacrylate and mixtures thereof, and the same applies to other similar expressions.

[(A) Carboxyl Group-Containing Resin]
As the carboxyl group-containing resin, conventionally known various carboxyl group-containing resins having a carboxyl group in the molecule can be used. In particular, a carboxyl group-containing photosensitive resin having an ethylenically unsaturated double bond in the molecule is preferable from the viewpoint of photocurability and development resistance. The ethylenically unsaturated double bonds are preferably derived from acrylic acid or methacrylic acid or derivatives thereof. When only a carboxyl group-containing resin having no ethylenically unsaturated double bonds is used, in order to make the composition photocurable, a compound having a plurality of ethylenically unsaturated groups in the molecule, i.e., photo It is necessary to use a reactive monomer together.
Specific examples of the carboxyl group-containing resin include the following compounds (both oligomers and polymers).

(1) A carboxyl group-containing resin obtained by copolymerizing an unsaturated carboxylic acid such as (meth)acrylic acid and an unsaturated group-containing compound such as styrene, α-methylstyrene, lower alkyl (meth)acrylate, isobutylene, or the like.

(2) Diisocyanates such as aliphatic diisocyanates, branched aliphatic diisocyanates, alicyclic diisocyanates, and aromatic diisocyanates; Carboxyl group-containing urethane resins obtained by polyaddition reaction of diol compounds such as polyols, polyester polyols, polyolefin polyols, acrylic polyols, bisphenol A alkylene oxide adduct diols, and compounds having phenolic hydroxyl groups and alcoholic hydroxyl groups.

(3) Diisocyanate and bifunctional epoxy resin such as bisphenol A type epoxy resin, hydrogenated bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bixylenol type epoxy resin, biphenol type epoxy resin ( A carboxyl group-containing photosensitive urethane resin produced by a polyaddition reaction of a meth)acrylate or its partial acid anhydride modified product, a carboxyl group-containing dialcohol compound and a diol compound.

(4) During the synthesis of the resin (2) or (3), a compound having one hydroxyl group and one or more (meth)acryloyl groups in the molecule such as hydroxyalkyl (meth)acrylate is added, and the terminal ( Meta) acrylated carboxyl group-containing photosensitive urethane resin.

(5) During the synthesis of the resin of (2) or (3), one isocyanate group and one or more (meth)acryloyl groups are added in the molecule, such as an equimolar reaction product of isophorone diisocyanate and pentaerythritol triacrylate. A carboxyl group-containing photosensitive urethane resin that is terminally (meth)acrylated by adding a compound having

(6) A carboxyl group-containing photosensitive resin obtained by reacting (meth)acrylic acid with a polyfunctional (solid) epoxy resin having a functionality of 2 or more and adding a dibasic acid anhydride to the hydroxyl group present in the side chain.

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

(8) A bifunctional oxetane resin is reacted with a dicarboxylic acid such as adipic acid, phthalic acid, and hexahydrophthalic acid, and the resulting primary hydroxyl group is treated with a dibasic such as phthalic anhydride, tetrahydrophthalic anhydride, and hexahydrophthalic anhydride. Carboxyl group-containing polyester resin to which acid anhydride is added.

(9) an epoxy compound having a plurality of epoxy groups in one molecule, a compound having at least one alcoholic hydroxyl group and one phenolic hydroxyl group in one molecule, such as p-hydroxyphenethyl alcohol; Maleic anhydride, tetrahydrophthalic anhydride, trimellitic anhydride, pyromellitic anhydride, adipic acid to the alcoholic hydroxyl group of the reaction product obtained by reacting with a monocarboxylic acid containing an unsaturated group such as acrylic acid. A carboxyl group-containing resin obtained by reacting a polybasic acid anhydride such as an acid.

(10) A reaction product obtained by reacting a compound having a plurality of phenolic hydroxyl groups in one molecule with an alkylene oxide such as ethylene oxide or propylene oxide and reacting an unsaturated group-containing monocarboxylic acid to obtain a reaction product A carboxyl group-containing photosensitive resin obtained by reacting a polybasic acid anhydride with a substance.

(11) Obtained by reacting a reaction product obtained by reacting a compound having a plurality of phenolic hydroxyl groups in one molecule with a cyclic carbonate compound such as ethylene carbonate or propylene carbonate with a monocarboxylic acid containing an unsaturated group. A carboxyl group-containing photosensitive resin obtained by reacting a reaction product with a polybasic acid anhydride.

(12) A carboxyl group-containing photosensitive resin obtained by further adding a compound having one epoxy group and one or more (meth)acryloyl groups in one molecule to the resins of (1) to (11).
In this specification, (meth)acrylate is a generic term for acrylate, methacrylate and mixtures thereof, and the same applies to other similar expressions.

(A) The acid value of the carboxyl group-containing resin is preferably 20 to 200 mgKOH/g. When the acid value of (A) the carboxyl group-containing resin is 20 to 200 mgKOH/g, the pattern formation of the cured product is facilitated. More preferably, it is 50 to 130 mgKOH/g.
Although the weight average molecular weight of the carboxyl group-containing resin differs 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 2,000 or more, the development resistance of the film in the exposed area is improved and the resolution is excellent. On the other hand, when the weight average molecular weight is 150,000 or less, the solubility of the unexposed area is good, the resolution is excellent, and the storage stability may be improved. A weight average molecular weight can be measured by a gel permeation chromatography.

The amount of the carboxyl group-containing resin (A) is, for example, 10 to 60% by mass, preferably 20 to 60% by mass, based on the total amount of the curable resin composition excluding the solvent. A coating strength of 10% by mass or more, preferably 20% by mass or more, can be improved. Moreover, by making it 60% by mass or less, the viscosity becomes appropriate and the workability improves. More preferably, it is 30 to 50% by mass.
These carboxyl group-containing resins are not limited to those listed above, and one type may be used alone, or a plurality of types may be mixed and used. Among them, carboxyl group-containing resins such as the carboxyl group-containing resins (10) and (11) synthesized using phenolic compounds as starting materials are excellent in B-HAST resistance and PCT resistance, and can be preferably used.

[(B) Photoinitiator]
As the photopolymerization initiator, any photopolymerization initiator known as a photopolymerization initiator or a photoradical generator can be used.

Examples of photopolymerization initiators include bis-(2,6-dichlorobenzoyl)phenylphosphine oxide, bis-(2,6-dichlorobenzoyl)-2,5-dimethylphenylphosphine oxide, bis-(2, 6-dichlorobenzoyl)-4-propylphenylphosphine oxide, bis-(2,6-dichlorobenzoyl)-1-naphthylphosphine oxide, bis-(2,6-dimethoxybenzoyl)phenylphosphine oxide, bis-( 2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, bis-(2,6-dimethoxybenzoyl)-2,5-dimethylphenylphosphine oxide, bis-(2,4,6- bisacylphosphine oxides such as trimethylbenzoyl)-phenylphosphine oxide (OMnirad 819 manufactured by IGM Resins); 2,6-dimethoxybenzoyldiphenylphosphine oxide, 2,6-dichlorobenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoylphenylphosphinic acid methyl ester, 2-methylbenzoyldiphenylphosphine oxide, pivaloylphenylphosphinic acid isopropyl ester, 2,4,6-trimethylbenzoyldiphenylphosphine oxide (IGM Resins) Monoacylphosphine oxides such as Omnirad (TPO); 1-hydroxy-cyclohexylphenyl ketone, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propane -1-one, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-propan-1-one, 2-hydroxy-2- Hydroxyacetophenones such as methyl-1-phenylpropan-1-one; benzoins such as benzoin, benzyl, benzoin methyl ether, benzoin ethyl ether, benzoin n-propyl ether, benzoin isopropyl ether, benzoin n-butyl ether; benzoin alkyl ethers benzophenone such as benzophenone, p-methylbenzophenone, Michler's ketone, methylbenzophenone, 4,4'-dichlorobenzophenone, 4,4'-bisdiethylaminobenzophenone amines; acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 1-hydroxycyclohexylphenylketone, 2-methyl-1-[4- (Methylthio)phenyl]-2-morpholino-1-propanone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1,2-(dimethylamino)-2-[(4- Acetophenones such as methylphenyl)methyl)-1-[4-(4-morpholinyl)phenyl]-1-butanone and N,N-dimethylaminoacetophenone; thioxanthone, 2-ethylthioxanthone, 2-isopropylthioxanthone, 2,4 -thioxanthones such as dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, 2,4-diisopropylthioxanthone; - anthraquinones such as chloroanthraquinone, 2-amyl anthraquinone, and 2-aminoanthraquinone; ketals such as acetophenone dimethyl ketal and benzyl dimethyl ketal; ethyl-4-dimethylaminobenzoate, 2-(dimethylamino)ethylbenzoate, p-dimethyl Benzoates such as ethyl benzoate; 1,2-octanedione, 1-[4-(phenylthio)-, 2-(O-benzoyloxime)], ethanone, 1-[9-ethyl-6-( 2-methylbenzoyl)-9H-carbazol-3-yl]-, 1-(O-acetyloxime) and other oxime esters; bis(η5-2,4-cyclopentadien-1-yl)-bis(2, 6-difluoro-3-(1H-pyrrol-1-yl)phenyl)titanium, bis(cyclopentadienyl)-bis[2,6-difluoro-3-(2-(1-pyrr-1-yl)ethyl ) Titanocenes such as phenyl]titanium; phenyl disulfide 2-nitrofluorene, butyroin, anisoine ethyl ether, azobisisobutyronitrile, tetramethylthiuram disulfide and the like. A photoinitiator may be used individually by 1 type, and may be used in combination of 2 or more type. Among them, monoacylphosphine oxides and oxime esters are preferred, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3 -yl]-,1-(O-acetyloxime) is more preferred.

The blending amount of the photopolymerization initiator is preferably 0.5 to 20 parts by mass with respect to 100 parts by mass of the carboxyl group-containing resin (A). When the amount is 0.5 parts by mass or more, good surface curability is achieved, and when the amount is 20 parts by mass or less, halation is less likely to occur and good resolution can be obtained.

[(C) epoxy resin having an epoxy equivalent of 130 or less]
The epoxy resin contained in the curable resin composition of the present invention is not particularly limited as long as it has an epoxy equivalent of 130 or less. When the epoxy equivalent is 130 or less, the cross-linking density can be increased, so the crack resistance is excellent, and the water absorption can be suppressed, so the reliability under high voltage is improved. Here, the reliability in a voltage-applied state can be evaluated by the reliability when a voltage of 15 V is applied. In addition, since the epoxy resin with a low epoxy equivalent is in a liquid state, it contributes to high filling of the inorganic filler. can.

As the epoxy resin, when an aliphatic epoxy compound among the epoxy resins (C) is synthesized by the epichlorohydrin route, the intermediate, which is an alcohol addition product, and the raw material alcohol compete as nucleophilic adducts. Since it induces a reaction, high molecular weight substances containing organic chlorides are likely to be produced. In general, the content of chlorine in aliphatic epoxy compounds increases, and this tendency is particularly strong in polyfunctional epoxies having many reaction points, and chlorine impurities are mixed in on the order of %. Therefore, the epoxy equivalent becomes large and exceeds 130. Therefore, in the present invention, it is desirable to synthesize epoxy by oxidizing an allyl ether that does not contain an organic chlorine compound.
By this synthesis method, the epoxy equivalent can be designed to be low, and since it does not contain halogen impurities, it can contribute to further improvement in insulation reliability.

(C) Epoxy resins having an epoxy equivalent of 130 or less include compounds having a glycidyl ether group. Compounds having a glycidyl ether group include compounds having the following skeletons (1) to (7), such as pentaerythritol tetraglycidyl ether and 2,2-bis(3-glycidyl-4-glycidyloxyphenyl)propane. , trimethylolpropane triglycidyl ether, and the like.

Epoxy resins having a glycidyl ether group are not particularly limited in structure, such as pentaerythritol type, trimethylolpropane type, glycerin type, etc., as understood from the compounds having the above skeletons (1) to (6). A known and commonly used structure having an epoxy equivalent of 130 or less can be used.

(C) The epoxy equivalent of the epoxy resin is 130 g/eq. It is preferably less than or equal to 100 g/eq. The following are more preferable.

The curable resin composition of the present invention may contain (C) an epoxy resin having an epoxy equivalent of 130 or less and a commonly used epoxy resin having an epoxy equivalent of more than 130 within a range that does not impair the unique effects of the present invention. can.

The amount of epoxy resin (C) to be blended is, for example, 1 to 100 parts by mass, preferably 10 to 80 parts by mass, more preferably 20 to 60 parts by mass, per 100 parts by mass of carboxyl group-containing resin (A). When the amount of the epoxy resin (C) is 10 parts by mass or more, the crack resistance and insulation reliability are further improved, and when it is 100 parts by mass or less, the storage stability is improved.

[(D) inorganic filler]
The curable resin composition of the present invention contains (D) an inorganic filler. Moreover, it is preferable that the inorganic filler is a surface-treated inorganic filler. (D) Including an inorganic filler further improves the crack resistance of the cured product.

The inorganic filler is not particularly limited, and known and commonly used fillers such as silica, crystalline silica, Neuburg silica, aluminum hydroxide, glass powder, talc, clay, magnesium carbonate, calcium carbonate, natural mica, synthetic mica, Inorganic fillers such as aluminum hydroxide, barium sulfate, barium titanate, iron oxide, non-fibrous glass, hydrotalcite, mineral wool, aluminum silicate, calcium silicate, and zinc white can be used. Among them, silica is preferable, and spherical silica is more preferable because it has a small surface area and is less likely to cause cracks because stress is dispersed over the entire surface.

Here, the surface-treated (D) inorganic filler refers to a filler that has undergone a treatment to react with at least one of (A) the carboxyl group-containing resin and (C) the epoxy resin to improve compatibility therebetween. . This surface treatment is not particularly limited, and a surface treatment capable of introducing a curable reactive group onto the surface of the inorganic filler is preferred.
The curable reactive group may be a thermosetting reactive group or a photocurable reactive group. Thermosetting reactive groups include hydroxyl group, carboxyl group, isocyanate group, amino group, imino group, epoxy group, oxetanyl group, mercapto group, methoxymethyl group, methoxyethyl group, ethoxymethyl group, ethoxyethyl group, oxazoline group, etc. is mentioned. A vinyl group, a styryl group, a methacryl group, an acryl group etc. are mentioned as a photocurable reactive group. Among them, the photocurable reactive group is preferably a methacrylic group, an acrylic group, or a vinyl group, and the thermosetting reactive group is preferably an epoxy group or an amino group. In addition, (D) the inorganic filler may have two or more curable reactive groups. (D) The inorganic filler is preferably surface-treated silica. Including surface-treated silica can lower the CTE and increase the glass transition temperature.

(D) The method of introducing the curable reactive group on the surface of the inorganic filler is not particularly limited, and may be introduced using a known and commonly used method. The surface of the inorganic filler may be treated with a coupling agent or the like.

(D) Surface treatment with a coupling agent is preferable as the surface treatment of the inorganic filler. A silane coupling agent, a titanium coupling agent, a zirconium coupling agent, an aluminum coupling agent, or the like can be used as the coupling agent. Among them, silane coupling agents are preferred.

As the silane coupling agent, a silane coupling agent capable of introducing a curing reactive group into the (D) inorganic filler is preferable. Examples of the silane coupling agent capable of introducing a thermosetting reactive group include a silane coupling agent having an epoxy group, a silane coupling agent having an amino group, a silane coupling agent having a mercapto group, and a silane coupling agent having an isocyanate group. Among them, a silane coupling agent having an epoxy group is more preferable. Silane coupling agents capable of introducing photocurable reactive groups include silane coupling agents having a vinyl group, silane coupling agents having a styryl group, silane coupling agents having a methacryl group, and silane coupling agents having an acryl group. Among them, a silane coupling agent having a methacrylic group is more preferable.

Examples of (D) inorganic fillers having no curable reactive group include inorganic fillers surface-treated with alumina.

(D) The inorganic filler may be blended in the curable resin composition of the present invention in a surface-treated state, and the surface-untreated inorganic filler and the surface treatment agent are separately blended in the composition. Although the inorganic filler may be surface-treated, it is preferable to incorporate a surface-treated inorganic filler in advance. By blending the inorganic filler which has been surface-treated in advance, it is possible to prevent deterioration in crack resistance and the like caused by the surface-treating agent not consumed in the surface treatment, which may remain when blended separately. In the case of pre-surface treatment, it is preferable to blend a pre-dispersed liquid (D) in which an inorganic filler is pre-dispersed in a solvent or a resin component. It is more preferable to mix the predispersed liquid into the composition after sufficiently surface-treating the surface-untreated inorganic filler when pre-dispersing it in the solvent.

In the curable resin composition of the present invention, the inorganic filler preferably has an average particle size of 2 μm or less because crack resistance is excellent. More preferably, it is 1 μm or less. In the present specification, the average particle size is the value of D50 measured using a Microtrac particle size analyzer manufactured by Nikkiso Co., Ltd.

The amount of the inorganic filler is preferably 25 to 85% by mass, more preferably 30 to 75% by mass, more preferably 35 to 70% by mass based on the total solid content of the curable resin composition. More preferred.

In the curable resin composition of the present invention, the (D) inorganic filler may be a combination of a surface-treated inorganic filler and an unsurface-treated inorganic filler. In that case, the surface-treated inorganic filler is preferably 30% by mass or more, more preferably 50% by mass or more, based on the total amount of the surface-treated inorganic filler and the non-surface-treated inorganic filler. , more preferably 70% by mass or more. Moreover, the inorganic filler that is not surface-treated is preferably spherical silica.

(Compound having an ethylenically unsaturated group)
A compound having one or more ethylenically unsaturated groups in the molecule is preferably used in the curable resin composition of the present invention. As the compound having an ethylenically unsaturated group, photopolymerizable oligomers, photopolymerizable vinyl monomers, and the like, which are known and commonly used photosensitive monomers, can be used. The compound having an ethylenically unsaturated group as used herein does not include the (A) carboxyl group-containing resin having an ethylenically unsaturated group.

Examples of photopolymerizable oligomers include unsaturated polyester-based oligomers and (meth)acrylate-based oligomers. (Meth)acrylate oligomers include epoxy (meth)acrylates such as phenol novolac epoxy (meth)acrylate, cresol novolak epoxy (meth)acrylate, bisphenol type epoxy (meth)acrylate, urethane (meth)acrylate, epoxyurethane (meth)acrylate, ) acrylates, polyester (meth)acrylates, polyether (meth)acrylates, polybutadiene-modified (meth)acrylates, and the like.

Examples of photopolymerizable vinyl monomers include known and commonly used monomers, for example, styrene derivatives such as styrene, chlorostyrene and α-methylstyrene; vinyl esters such as vinyl acetate, vinyl butyrate and vinyl benzoate; vinyl isobutyl ether, vinyl- Vinyl ethers such as n-butyl ether, vinyl-t-butyl ether, vinyl-n-amyl ether, vinyl isoamyl ether, vinyl-n-octadecyl ether, vinylcyclohexyl ether, ethylene glycol monobutyl vinyl ether, triethylene glycol monomethyl vinyl ether; acrylamide, (Meth)acrylamides such as methacrylamide, N-hydroxymethylacrylamide, N-hydroxymethylmethacrylamide, N-methoxymethylacrylamide, N-ethoxymethylacrylamide, N-butoxymethylacrylamide; triallyl isocyanurate, diallyl phthalate, Allyl compounds such as diallyl isophthalate; 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, isobornyl (meth)acrylate, phenyl (meth)acrylate, phenoxyethyl (meth)acrylate, etc. Esters of (meth)acrylic acid; hydroxyalkyl (meth)acrylates such as hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, and pentaerythritol tri(meth)acrylate; methoxyethyl (meth)acrylate, ethoxyethyl Alkoxyalkylene glycol mono (meth) acrylates such as (meth) acrylate; ethylene glycol di (meth) acrylate, butanediol di (meth) acrylates, neopentyl glycol di (meth) acrylate, 1,6-hexanediol di ( Alkylene polyol poly(meth)acrylates such as meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate; diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate; Polyoxyalkylene glycol poly(meth)acrylates such as (meth)acrylates, ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane tri(meth)acrylates, etc. i) Acrylates; poly(meth)acrylates such as neopentylglycol hydroxypivalate di(meth)acrylate; isocyanurate-type poly(meth)acrylates such as tris[(meth)acryloxyethyl]isocyanurate, etc. mentioned. These can be used alone or in combination of two or more according to the required properties.

The compounding amount of the compound having an ethylenically unsaturated bond is preferably 3 to 40 parts by mass with respect to 100 parts by mass of the carboxyl group-containing resin (A). When it is 3 parts by mass or more, the surface curability is improved, and when it is 40 parts by mass or less, halation is suppressed. More preferably, it is 5 to 30 parts by mass.

(Thermosetting catalyst)
The curable resin composition of the present invention preferably contains a thermosetting catalyst. Such thermosetting catalysts include, for example, imidazole, 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 4-phenylimidazole, 1-cyanoethyl-2-phenylimidazole. , 1-(2-cyanoethyl)-2-ethyl-4-methylimidazole; dicyandiamide, benzyldimethylamine, 4-(dimethylamino)-N,N-dimethylbenzylamine, 4-methoxy-N,N amine compounds such as -dimethylbenzylamine and 4-methyl-N,N-dimethylbenzylamine; hydrazine compounds such as adipic acid dihydrazide and sebacic acid dihydrazide; and phosphorus compounds such as triphenylphosphine. Also, guanamine, acetoguanamine, benzoguanamine, melamine, 2,4-diamino-6-methacryloyloxyethyl-S-triazine, 2-vinyl-2,4-diamino-S-triazine, 2-vinyl-4,6-diamino S-triazine derivatives such as S-triazine/isocyanuric acid adducts and 2,4-diamino-6-methacryloyloxyethyl-S-triazine/isocyanuric acid adducts can also be used, and these adhesion-imparting agents are preferred. A compound that also functions is used in conjunction with a thermosetting catalyst.

The amount of the thermosetting catalyst is preferably 0.05 to 40 parts by mass, more preferably 0.1 to 30 parts by mass, per 100 parts by mass of the epoxy resin (C).

(curing agent)
The curable resin composition of the present invention can contain a curing agent. Curing agents include phenol resins, polycarboxylic acids and their acid anhydrides, cyanate ester resins, active ester resins, maleimide compounds, alicyclic olefin polymers, and the like. Curing agents may be used singly or in combination of two or more.

In the curing agent, the ratio of the functional group capable of thermosetting reaction such as the epoxy group of the thermosetting resin such as (C) epoxy resin and the functional group in the curing agent that reacts with the functional group is It is preferable to blend the functional group/functional group capable of thermosetting reaction (equivalence ratio) in a ratio of 0.2 to 3. By setting it as the said range, it is excellent in the balance of storage stability and curability.

(coloring agent)
The curable resin composition of the present invention may contain a coloring agent. As the coloring agent, known coloring agents such as red, blue, green, yellow, black, and white can be used, and any of pigments, dyes, and pigments can be used. However, it is preferable not to contain a halogen from the viewpoint of environmental load reduction and influence on the human body.

The amount of the colorant to be added is not particularly limited, but is preferably 10 parts by mass or less, particularly preferably 0.1 to 7 parts by mass, per 100 parts by mass of the carboxyl group-containing resin (A).

(Organic solvent)
The curable resin composition of the present invention may contain an organic solvent for the purpose of preparing the composition and adjusting the viscosity when applied to a substrate or carrier film. Examples of organic solvents include ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene, xylene and tetramethylbenzene; cellosolve, methyl cellosolve, butyl cellosolve, carbitol, methyl carbitol, butyl carbitol, propylene glycol monomethyl ether; , dipropylene glycol monomethyl ether, dipropylene glycol diethyl ether, diethylene glycol monomethyl ether acetate, tripropylene glycol monomethyl ether; ethyl acetate, butyl acetate, butyl lactate, cellosolve acetate, butyl cellosolve acetate, carbitol acetate, butyl carbi Esters such as tall acetate, propylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether acetate, and propylene carbonate; aliphatic hydrocarbons such as octane and decane; petroleum solvents such as petroleum ether, petroleum naphtha, and solvent naphtha; Conventional organic solvents can be used. These organic solvents can be used alone or in combination of two or more.

(Other optional ingredients)
Furthermore, the curable resin composition of the present invention may be blended with other known and commonly used additives in the field of electronic materials. Other additives include thermal polymerization inhibitors, ultraviolet absorbers, silane coupling agents, plasticizers, flame retardants, antistatic agents, anti-aging agents, antibacterial/antifungal agents, antifoaming agents, leveling agents, and thickeners. agent, adhesion imparting agent, thixotropy imparting agent, photoinitiation aid, sensitizer, thermoplastic resin, organic filler, release agent, surface treatment agent, dispersant, dispersion aid, surface modifier, stabilizer , phosphors, and the like.

The curable resin composition of the present invention may contain (C) a thermosetting resin other than the epoxy resin within a range that does not impair the effects of the present invention. The thermosetting resin may be a resin that cures by heating and exhibits electrical insulation. Examples include (C) epoxy compounds other than epoxy resins, oxetane compounds, melamine resins, and silicone resins. These may be used in combination.

The curable resin composition of the present invention may be used as a dry film or as a liquid. When used as a liquid, it may be one-liquid or two-liquid or more.

Next, the dry film of the present invention has a resin layer obtained by coating and drying the curable resin composition of the present invention on a carrier film. When forming a dry film, first, the curable resin composition of the present invention is diluted with the above organic solvent to adjust the viscosity to an appropriate value, and then a comma coater, blade coater, lip coater, rod coater, and squeeze coater are used. , a reverse coater, a transfer roll coater, a gravure coater, a spray coater, or the like to a uniform thickness on the carrier film. After that, the applied composition is usually dried at a temperature of 40 to 130° C. for 1 to 30 minutes to form a resin layer. The coating thickness is not particularly limited, but is generally selected as appropriate in the range of 3 to 150 μm, preferably 5 to 60 μm, in terms of thickness after drying.

As the carrier film, a plastic film is used, and for example, a polyester film such as polyethylene terephthalate (PET), a polyimide film, a polyamideimide film, a polypropylene film, a polystyrene film, or the like can be used. The thickness of the carrier film is not particularly limited, but is generally selected appropriately within the range of 10 to 150 μm. More preferably, it is in the range of 15 to 130 μm.

After forming the resin layer composed of the curable resin composition of the present invention on the carrier film, for the purpose of preventing dust from adhering to the surface of the resin layer, a peelable cover is further placed on the surface of the resin layer. It is preferred to laminate the films. As the peelable cover film, for example, a polyethylene film, a polytetrafluoroethylene film, a polypropylene film, surface-treated paper, or the like can be used. Any cover film may be used as long as the adhesive force is smaller than the adhesive force between the resin layer and the carrier film when the cover film is peeled off.

In the present invention, the curable resin composition of the present invention may be coated on the cover film and dried to form a resin layer, and a carrier film may be laminated on the surface of the resin layer. That is, either a carrier film or a cover film may be used as the film to which the curable resin composition of the present invention is applied when producing the dry film in the present invention.

The printed wiring board of the present invention has a cured product obtained from the curable resin composition or the resin layer of the dry film of the present invention. As a method for producing the printed wiring board of the present invention, for example, the curable resin composition of the present invention is adjusted to a viscosity suitable for the coating method using the above organic solvent, and is coated on the substrate by a dip coating method, After applying by a method such as flow coating, roll coating, bar coating, screen printing, or curtain coating, the organic solvent contained in the composition is volatilized and dried (temporary drying) at a temperature of 60 to 100 ° C. Thus, a tack-free resin layer is formed. In the case of a dry film, the resin layer is formed on the substrate by laminating it on the substrate with a laminator or the like so that the resin layer is in contact with the substrate, and then peeling off the carrier film.

Examples of the substrate include printed wiring boards and flexible printed wiring boards on which circuits are formed in advance using copper or the like, paper phenol, paper epoxy, glass cloth epoxy, glass polyimide, glass cloth/non-woven cloth epoxy, glass cloth/paper epoxy. , Synthetic fiber epoxy, fluororesin, polyethylene, polyphenylene ether, polyphenylene oxide, cyanate, and other materials such as copper-clad laminates for high-frequency circuits, and copper-clad laminates of all grades (FR-4, etc.) Plates, metal substrates, polyimide films, PET films, polyethylene naphthalate (PEN) films, glass substrates, ceramic substrates, wafer plates and the like can also be used.

Volatilization drying performed after applying the curable resin composition of the present invention can be performed using a hot air circulation drying oven, an IR oven, a hot plate, a convection oven, etc. A method of bringing hot air into countercurrent contact and a method of blowing hot air onto the support from a nozzle) can be used.

After forming a resin layer on the printed wiring board, it is selectively exposed to active energy rays through a photomask having a predetermined pattern, and the unexposed area is treated with a dilute alkaline aqueous solution (e.g., 0.3 to 3% by mass sodium carbonate aqueous solution). ) to form a pattern of the cured product. Furthermore, the cured product is cured by heat after irradiation with active energy rays (for example, 100 to 220 ° C), or by irradiation with active energy rays after heat curing, or by final curing (main curing) only by heat curing. Forms a cured film with excellent properties such as toughness and hardness.
When the curable resin composition of the present invention contains a photobase generator, it is preferably heated after exposure and before development. Heating for 60 minutes is preferred.

The exposure machine used for the active energy ray irradiation may be any device equipped with a high-pressure mercury lamp, ultra-high pressure mercury lamp, metal halide lamp, mercury short arc lamp, etc., and irradiating ultraviolet rays in the range of 350 to 450 nm. In addition, a direct writing device (eg, a laser direct imaging device that draws an image with a laser directly from CAD data from a computer) can also be used. The lamp light source or laser light source of the direct drawing machine may have a maximum wavelength in the range of 350 to 450 nm. The amount of exposure for image formation varies depending on the film thickness and the like, but can generally be in the range of 10-1000 mJ/cm ² , preferably in the range of 20-800 mJ/cm ² .

Examples of the developing method include a dipping method, a shower method, a spray method, a brush method, and the like. Alkaline aqueous solutions such as ammonia and amines can be used.

The curable resin composition of the present invention is preferably used to form a cured film on a printed wiring board, more preferably used to form a permanent film, and more preferably a solder resist, Used to form interlayer insulating layers, coverlays. Further, according to the curable resin composition of the present invention, it is possible to obtain a cured product having excellent crack resistance and insulation reliability. For example, it can be suitably used for forming a package substrate, especially a permanent film (especially a solder resist) for FC-BGA.

EXAMPLES The present invention will be described in more detail below using examples, but the present invention is not limited to the following examples. In the following description, "parts" and "%" are based on mass unless otherwise specified.
Each component shown in Tables 1 to 3 was blended in the ratio shown in Tables 1 to 3, premixed with a stirrer, and then kneaded with a three-roll mill for Examples 1 to 23, Reference Examples 1 to 5, and Comparative Example 1. ~4 curable resin compositions were prepared. Various properties of the resulting curable composition were evaluated, and the results are shown in Tables 1-3.

The alkali-developable resins in Tables 1-3 were prepared as follows.
[(A-1) Synthesis of alkali-developable resin]
An autoclave equipped with a thermometer, a nitrogen introduction device/alkylene oxide introduction device and a stirrer was charged with 119.4 parts of a novolak cresol resin (Showol CRG951 manufactured by Showa Denko Co., Ltd., OH equivalent: 119.4) and 1.5 parts of potassium hydroxide. 19 parts and 119.4 parts of toluene were introduced, the inside of the system was replaced with nitrogen while stirring, and the temperature was raised. Next, 63.8 parts of propylene oxide was gradually added dropwise and reacted at 125-132° C. and 0-4.8 kg/cm ² for 16 hours. After cooling to room temperature, 1.56 parts of 89% phosphoric acid was added to and mixed with the reaction solution to neutralize potassium hydroxide. 9 g/eq.) of a novolak-type cresol resin propylene oxide reaction solution was obtained. This was an average addition of 1.08 moles of propylene oxide per equivalent of phenolic hydroxyl group.
293.0 parts of the propylene oxide reaction solution of the obtained novolak-type cresol resin, 43.2 parts of acrylic acid, 11.53 parts of methanesulfonic acid, 0.18 parts of methylhydroquinone and 252.9 parts of toluene were mixed with a stirrer at a temperature of The mixture was introduced into a reactor equipped with a meter and an air blowing tube, air was blown in at a rate of 10 ml/min, and reaction was carried out at 110° C. for 12 hours while stirring. As for the water produced by the reaction, 12.6 parts of water was distilled as an azeotrope with toluene. After cooling to room temperature, the resulting reaction solution was neutralized with 35.35 parts of a 15% aqueous sodium hydroxide solution and then washed with water. After that, the toluene was removed by an evaporator while replacing it with 118.1 parts of diethylene glycol monoethyl ether acetate to obtain a novolac type acrylate resin solution. Next, 332.5 parts of the resulting novolac acrylate resin solution and 1.22 parts of triphenylphosphine were introduced into a reactor equipped with a stirrer, thermometer and air blowing tube, and air was added at a rate of 10 ml/min. 60.8 parts of tetrahydrophthalic anhydride was gradually added while stirring, reacted at 95 to 101° C. for 6 hours, cooled, and taken out. Thus, a solution of photosensitive carboxyl group-containing resin A-1 having a solid content of 65% and a solid acid value of 87.7 mgKOH/g was obtained. Hereinafter, the solution of this carboxyl group-containing photosensitive resin is referred to as resin solution A-1.

[(A-2) Synthesis of alkali-developable resin]
To 600 g of diethylene glycol monoethyl ether acetate was added 1070 g of an ortho-cresol novolac type epoxy resin (EPICLON N-695 manufactured by DIC, softening point 95°C, epoxy equivalent weight 214, average functional group number 7.6) (number of glycidyl groups (total number of aromatic rings): 5. 0 mol), 360 g (5.0 mol) of acrylic acid, and 1.5 g of hydroquinone were charged, heated to 100° C. with stirring, and uniformly dissolved.
Then, 4.3 g of triphenylphosphine was charged, heated to 110° C. and reacted for 2 hours, then heated to 120° C. and reacted for further 12 hours. 415 g of an aromatic hydrocarbon (Solvesso 150) and 456.0 g (3.0 mol) of tetrahydrophthalic anhydride were added to the resulting reaction solution, reacted at 110° C. for 4 hours, cooled, and photosensitive carboxyl A group-containing resin solution was obtained. The solid content of the resin solution thus obtained was 65%, and the acid value of the solid content was 89 mgKOH/g. Hereinafter, the solution of this carboxyl group-containing photosensitive resin is referred to as resin solution A-2.

[(A-3) Synthesis of alkali-developable resin]
A flask equipped with a thermometer, a stirrer, a dropping funnel, and a reflux condenser was heated with 325.0 parts of dipropylene glycol monomethyl ether as a solvent to 110° C., and 174.0 parts of methacrylic acid and ε-caprolactone-modified methacrylic acid were added. (Average molecular weight 314) 174.0 parts, 77.0 parts of methyl methacrylate, 222.0 parts of dipropylene glycol monomethyl ether, and t-butyl peroxy 2-ethylhexanoate as a polymerization catalyst (Perbutyl O ) 12.0 parts of the mixture was added dropwise over 3 hours and stirred at 110° C. for 3 hours to deactivate the polymerization catalyst to obtain a resin solution.
After cooling this resin solution, 289.0 parts of Cychromer A200 manufactured by Daicel Chemical Industries, Ltd., 3.0 parts of triphenylphosphine, and 1.3 parts of hydroquinone monomethyl ether are added, heated to 100° C., and stirred. A ring-opening addition reaction of the epoxy group was carried out to obtain a photosensitive carboxyl group-containing resin solution.
The resin solution thus obtained had a weight average molecular weight (Mw) of 15,000, a solid content of 57%, and an acid value of the solid matter of 79.8 mgKOH/g. Hereinafter, the solution of this carboxyl group-containing photosensitive resin is referred to as resin solution A-3.

In Tables 1-3, the photopolymerization initiators are as follows.
(B-1): Omnirad TPO (2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide) manufactured by IGM Resins
(B-2): Omnirad 907 (2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one) manufactured by IGM Resins
(B-3): BASF Japan Irgacure OXE02 (ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-1-(o-acetyloxime)

In Tables 1 to 3, (C) epoxy resins having an epoxy equivalent of 130 or less are as follows.
(C-1): an epoxy resin having the skeleton of (1) (epoxy equivalent 96)
(C-2): epoxy resin having the skeleton of (2) (epoxy equivalent: 113)
(C-3): Epoxy resin having the skeleton of (3) (epoxy equivalent 91)
(C-4): an epoxy resin having the skeleton of (4) (epoxy equivalent: 119)
(C-5): epoxy resin having the skeleton of (5) (epoxy equivalent: 120)
(C-6): an epoxy resin having the skeleton of (6) (epoxy equivalent: 130)
(C-7): epoxy resin having the skeleton of (7) (epoxy equivalent: 130)

（Ｃ－９）ダウケミカル社製ＤＥＮ４３１（フェノールノボラックエポキシ樹脂）
（Ｃ－１０）ＤＩＣ社製Ｎ－８７０ ７５ＥＡ（ビスフェノールＡノボラック型エポキシ樹脂）
（Ｃ－１１）ＤＩＣ社製ＥＸＡ－７２４１（トリスフェノールメタン型エポキシ樹脂）
（Ｃ－１２）下記骨格を有する特殊エポキシ樹脂

The cured resin compositions in Tables 1 to 3 may contain the following epoxy resins (C-8) to (C-12) as epoxy resins other than (C) epoxy resins having an epoxy equivalent of 130 or less.
(C-8): Special epoxy resin having the following silsesquioxane skeleton

(C-9) DEN431 manufactured by Dow Chemical Co. (phenol novolac epoxy resin)
(C-10) N-870 75EA manufactured by DIC (bisphenol A novolak type epoxy resin)
(C-11) DIC EXA-7241 (trisphenolmethane type epoxy resin)
(C-12) Special epoxy resin having the following skeleton

The inorganic fillers in Tables 1-3 were prepared or procured as follows.
[(D-1) Inorganic treatment → Preparation of methacrylsilane-treated silica slurry]
A water slurry of 50 g of spherical silica particles (SFP-20M manufactured by Denka, average particle size: 400 nm) was heated to 70° C., and then 1% of a 10% sodium silicate aqueous solution was added to the silica particles in terms of silica particles. . Hydrochloric acid was added to this slurry to adjust the pH to 4, and the slurry was aged for 30 minutes. Further, while maintaining the pH at 7±1 with hydrochloric acid, a 20% sodium aluminate (NaAlO ₂ ) aqueous solution was added to the silica particles to form alumina ( 5% in terms of Al ₂ O ₃ ) was added. After this, a 20% aqueous sodium hydroxide solution was added to adjust the pH to 7 and aged for 30 minutes. Thereafter, the slurry was filtered with a filter press, washed with water, and dried in a vacuum to obtain a solid of silica particles coated with hydrated oxide of silicon and hydrated oxide of aluminum. 50 g of silica particles coated with hydrated oxide of silicon obtained in the same manner as above, 48 g of PMA as a solvent, and 2 g of a silane coupling agent having a methacrylic group (KBM-503 manufactured by Shin-Etsu Chemical Co., Ltd.) were uniformly mixed. A dispersed silica solvent dispersion was obtained.

[(D-2) Preparation of inorganically treated silica slurry]
A water slurry of 50 g of spherical silica particles (SFP-20M manufactured by Denka, average particle size: 400 nm) was heated to 70° C., and then 1% of a 10% sodium silicate aqueous solution was added to the silica particles in terms of silica particles. . Hydrochloric acid was added to this slurry to adjust the pH to 4, and the slurry was aged for 30 minutes. Further, while maintaining the pH at 7±1 with hydrochloric acid, a 20% sodium aluminate (NaAlO ₂ ) aqueous solution was added to the silica particles to form alumina ( 5% in terms of Al ₂ O ₃ ) was added. After this, a 20% aqueous sodium hydroxide solution was added to adjust the pH to 7 and aged for 30 minutes. Thereafter, the slurry was filtered with a filter press, washed with water, and dried in a vacuum to obtain a solid of silica particles coated with hydrated oxide of silicon and hydrated oxide of aluminum. A silica solvent dispersion product was obtained by uniformly dispersing 50 g of silica particles coated with a hydrated oxide of silicon obtained in the same manner as above, 48 g of PMA as a solvent, and 2 g of a dispersant (BYK-111).
[(D-3) Preparation of methacrylsilane-treated silica slurry]
50 g of spherical silica particles (SFP-20M manufactured by Denka, average particle size: 400 nm), 48 g of PMA as a solvent, and 2 g of a silane coupling agent having a methacrylic group (KBM-503 manufactured by Shin-Etsu Chemical Co., Ltd.) were uniformly dispersed. A silica solvent dispersion was obtained.
[(D-4) Preparation of silica slurry]
A silica solvent dispersion product was obtained by uniformly dispersing 50 g of spherical silica particles (SFP-20M manufactured by Denka, average particle size: 400 nm), 48 g of PMA as a solvent, and 2 g of a dispersant (BYK-111).
[(D-5) Inorganic treatment → preparation of methacrylsilane-treated barium sulfate slurry]
After heating an aqueous slurry of 50 g of barium sulfate particles (precipitated barium 100 manufactured by Sakai Chemical Industry Co., Ltd.) to 70° C., 10% sodium silicate aqueous solution was added to the silica particles in an amount of 1% in terms of silica particles. Hydrochloric acid was added to this slurry to adjust the pH to 4, and the slurry was aged for 30 minutes. Further, while maintaining the pH at 7±1 with hydrochloric acid, a 20% sodium aluminate (NaAlO ₂ ) aqueous solution was added to the silica particles to form alumina ( 5% in terms of Al ₂ O ₃ ) was added. After this, a 20% aqueous sodium hydroxide solution was added to adjust the pH to 7 and aged for 30 minutes. Thereafter, the slurry was filtered with a filter press, washed with water, and dried in a vacuum to obtain a solid of barium sulfate particles coated with hydrated oxide of silicon and hydrated oxide of aluminum. 50 g of barium sulfate particles coated with hydrated oxide of silicon obtained in the same manner as above, 48 g of PMA as a solvent, and 2 g of a silane coupling agent having a methacrylic group (KBM-503 manufactured by Shin-Etsu Chemical Co., Ltd.). A uniformly dispersed silica solvent dispersion product was obtained.
[(D-6) Preparation of inorganically treated barium sulfate slurry]
After heating an aqueous slurry of 50 g of barium sulfate particles (precipitated barium 100 manufactured by Sakai Chemical Industry Co., Ltd.) to 70° C., 10% sodium silicate aqueous solution was added to the silica particles in an amount of 1% in terms of silica particles. Hydrochloric acid was added to this slurry to adjust the pH to 4, and the slurry was aged for 30 minutes. Further, while maintaining the pH at 7±1 with hydrochloric acid, a 20% sodium aluminate (NaAlO ₂ ) aqueous solution was added to the silica particles to form alumina ( 5% in terms of Al ₂ O ₃ ) was added. After this, a 20% aqueous sodium hydroxide solution was added to adjust the pH to 7 and aged for 30 minutes. Thereafter, the slurry was filtered with a filter press, washed with water, and dried in a vacuum to obtain a solid of barium sulfate particles coated with hydrated oxide of silicon and hydrated oxide of aluminum. A silica solvent dispersion product was obtained by uniformly dispersing 50 g of barium sulfate particles coated with hydrated oxide of silicon obtained in the same manner as above, 48 g of PMA as a solvent, and 2 g of a dispersant (BYK-111). .
[(D-7) Preparation of methacrylsilane-treated barium sulfate slurry]
A barium sulfate solvent prepared by uniformly dispersing 50 g of barium sulfate particles (precipitated barium 100 manufactured by Sakai Chemical Industry Co., Ltd.), 48 g of PMA as a solvent, and 2 g of a silane coupling agent having a methacrylic group (KBM-503 manufactured by Shin-Etsu Chemical Co., Ltd.). A dispersed product was obtained.
[(D-8) Preparation of barium sulfate slurry]
A barium sulfate solvent-dispersed product was obtained by uniformly dispersing 50 g of barium sulfate particles (precipitated barium 100 manufactured by Sakai Chemical Industry Co., Ltd.), 48 g of PMA as a solvent, and 2 g of a dispersant (BYK-111).

The cured resin compositions of Tables 1-3 may also contain the following components.
・DPHA (dipentaerythritol hexaacrylate) manufactured by Nippon Kayaku Co., Ltd.
・ CZ-601D (blue colorant) manufactured by Nikko Bix Co., Ltd., colorant content 12% by mass
・ CZ-309D (yellow coloring agent) manufactured by Nikko Bix Co., Ltd., coloring agent content 10% by mass
・DICY (dicyandiamide)

(Preparation of dry film)
The curable resin composition of each example and each comparative example shown in Tables 1 to 3 was coated on PET at 10 m / min using a die coater. A dry film was obtained by passing through a drying oven at 120° C. to volatilize the solvent.

(Preparation of standard evaluation board)
The dry film obtained by the above method was laminated on a test substrate using a vacuum laminator CVP-300 (manufactured by Nikko Materials Co., Ltd.) to obtain a laminate of the photosensitive resin composition. Using DXP-3580 (manufactured by ORC Co., Ltd., ultra-high pressure mercury lamp DI exposure machine), the laminate was subjected to pattern exposure with a Stouffer 41-step tablet so as to obtain 10 curing steps according to the evaluation items. After 10 minutes from the exposure, the PET film was peeled off, and development was carried out with a 1% by mass sodium carbonate aqueous solution at 30° C. for a development time twice the break point (shortest development time). After that, the substrate was exposed at 2000 mJ with a UV conveyor (a metal halide lamp manufactured by ORC) and cured at 170° C. for 60 minutes in a thermal circulation box furnace to obtain an evaluation substrate.

<Glass transition temperature Tg and coefficient of thermal expansion CTE>
Each curable resin composition was formed on a copper foil substrate so as to have a film thickness of about 40 μm, and exposed in a strip-shaped pattern of 50 mm×3 mm. After that, development and curing were performed under predetermined conditions.
The cured film of the evaluation substrate obtained above was peeled off from the copper foil and evaluated. The measurement was performed using a TMA measurement device (manufactured by Shimadzu Corporation, model name: TMA6000), and Tg, CTEα1 (0° C.-50°) and CTEα2 (200° C.-250° C.) were evaluated. Evaluation criteria are as follows.
Tg
◎ ... 180 ° C. or higher ○ ... 170 ° C. or higher and less than 180 △ ... 160 ° C. or higher and less than 170 × ... less than 160 ° C. CTEα1
◎ ... less than 35 ppm ○ ... 35 ppm or more and less than 40 ppm △ ... 40 ppm or more and less than 45 ppm × ... 45 ppm or more CTEα2
◎ ... less than 100 ppm ○ ... 100 ppm or more and less than 105 ppm △ ... 105 ppm or more and less than 110 ppm × ... 110 ppm or more

<Modulus E>
An evaluation substrate having a cured film was obtained in the same manner as in the evaluation method of the glass transition temperature Tg.
The cured film of the evaluation substrate obtained above was peeled off from the copper foil and evaluated. The measurement was performed using a DMA measurement device (manufactured by Shimadzu Corporation, model name: DMS6100), and the E (elastic modulus) at 250°C was evaluated. Evaluation criteria are as follows.
⊚: 1 × 10 ⁹ Pa or more ○: 5 × 10 ⁸ Pa or more and less than 1 × 10 ⁹ Pa △: 1 × 10 ⁸ Pa or more and less than 5 × 10 ⁸ Pa x: less than 1 × 10 ⁸ Pa

<Toughness evaluation (preparation of copper foil substrate with resin layer)>
A curable resin composition was formed on a copper foil substrate so as to have a film thickness of about 40 μm, and was exposed in a strip-shaped pattern of 80 mm×10 mm. After that, development and curing were performed under predetermined conditions.
The cured film of the evaluation substrate obtained above was peeled off from the copper foil and evaluated. The measurement was performed using a tensile tester (manufactured by Shimadzu Corporation, model name: AGS-G 100N), and the maximum point stress or elongation at break was evaluated. Evaluation criteria are as follows.
◎: Maximum stress of 80 MPa or more, or elongation at break of 6% or more ○: Maximum stress of 70 MPa or more and less than 80 MPa, or elongation at break of 4% or more and less than 6% △: Maximum stress of 50 MPa or more and less than 70 MPa, elongation at break rate 2% or more and less than 4% × ... maximum point stress less than 50 MPa, or elongation at break less than 2%

<Resolution evaluation>
A curable resin composition was formed to a film thickness of about 20 μm on a plated copper substrate treated with CZ-8101B at an etching rate of 1.0 μm/m ² and exposed with various opening patterns. Thereafter, development was performed under predetermined conditions, and curing was performed under evaluation conditions.
The opening diameter of the evaluation substrate obtained above was observed, and evaluation was performed by confirming that there was no occurrence of halation or undercut.
⊚: Good opening diameter at 60 µm ○: Good opening diameter at 70 µm △: Good opening diameter at 80 µm ×: No good opening diameter at 80 µm or development impossible

<HAST resistance>
A curable resin composition was formed to a film thickness of about 20 μm on a substrate having a comb pattern of L/S=20/20 μm which had been treated with CZ-8101B at an etching rate of 1.0 μm/m ² . , a full-surface exposure was performed. After that, development and curing were performed under predetermined conditions.
After that, the electrodes were connected and a HAST test was performed under the conditions of 130°C, 85%, and 5V.
◎: 400h pass
○: 350h pass
△: 300h pass
×: NG within 250 hours

<High voltage HAST resistance (B-HAST resistance)>
A curable resin composition was formed to a film thickness of about 20 μm on a substrate having a comb pattern of L/S=20/20 μm which had been treated with CZ-8101B at an etching rate of 1.0 μm/m ² . , a full-surface exposure was performed. After that, development and curing were performed under predetermined conditions.
After that, the electrodes were connected and the HAST test was performed under the conditions of 130 degrees, 85%, and 15V.
◎: 300h pass
○: 250h pass
△: 200h pass
×: NG within 150 hours

<Crack resistance (TCT resistance)>
On a package substrate treated with CZ-8101B at an etching rate of 1.0 μm/m ² , a curable resin composition was formed to a film thickness of about 18 μm on Cu, and the copper pad was exposed to SRO 80 μm. rice field. After that, development and curing were performed under predetermined conditions. After that, Au plating treatment, solder bump formation, and Si chip mounting were performed to obtain an evaluation substrate.
The evaluation substrate obtained above was placed in a thermal cycler in which temperature cycles were performed between −65° C. and 150° C., and a TCT (Thermal Cycle Test) was performed. Then, the surface of the cured film after 600 cycles, 800 cycles and 1000 cycles was observed. Judgment criteria are as follows.
◎: No abnormalities after 1000 cycles ○: No abnormalities after 800 cycles, cracks after 1000 cycles △: No abnormalities after 600 cycles, cracks after 800 cycles ×: Cracks after 600 cycles

From the results shown in Tables 1 to 3, the cured products of the curable resin compositions of Examples 1 to 23 and Reference Examples 1 to 5 of the present invention are excellent in crack resistance and insulation reliability, especially insulation reliability at high voltage. It can be seen that it is superior to In contrast, when the curable resin compositions of Comparative Examples 1 to 4 were used, it was difficult to obtain insulation reliability at high voltage.

Claims (6)

(A) a carboxyl group-containing resin;
(B) a photoinitiator;
(C) an epoxy resin having a glycidyl ether group with an epoxy equivalent of 100 or less;
(D) an inorganic filler;
A curable resin composition comprising: 2. The curable resin composition according to claim 1 , wherein the inorganic filler (D) is surface-treated. 3. The curable resin composition according to claim 1, wherein the mixing ratio of the inorganic filler (D) is 25 to 85% by mass. A dry film comprising a resin layer obtained by coating the curable resin composition according to any one of claims 1 to 3 on a film and drying the composition. A cured product obtained by curing the curable resin composition according to any one of claims 1 to 3 or the resin layer of the dry film according to claim 4 . A printed wiring board comprising the cured product according to claim 5 .