JP7316071B2 - Curable resin compositions, dry films, cured products and electronic components - Google Patents

Description

The present invention relates to a curable resin composition, dry film, cured product and electronic component.

2. Description of the Related Art In recent years, there has been a marked trend towards smaller size and higher density mounting methods in the field of electronic equipment for communication, consumer use, industrial use, etc. Along with this trend, electronic components are becoming smaller. Small mobile devices such as mobile phones and smartphones in particular use a large number of multilayer electronic components. In recent years, the demand has expanded rapidly. This multilayer chip inductor is formed by laminating a large number of ceramic sheets on which a coil pattern is printed with metal paste to create a three-dimensional coil inside. Ultimately, ceramic is fired at a high temperature to form an inductor, but problems such as cracks during firing and the need to stabilize Q characteristics due to a low dielectric constant have led to demand for chip inductors made of resin materials instead of ceramics. (For example, Patent Document 1).

As one method of forming a coil pattern, for a resin material, a tenting method using copper foil etching can be cited. In conventional ceramic inductors, circuit coils (conductor wires) are formed by screen-printing conductive paste. It was difficult to control the thickness of the conductor because it decreased. On the other hand, in the copper foil tenting method, the thickness of the copper foil and the plating thickness can be easily adjusted, and by freely increasing the thickness of the copper circuit coil, the resistance is lowered and the Q value can be increased. Furthermore, since the thickness does not decrease during the firing process, the thickness can be easily controlled.

JP 2016-225611 A

A multilayer chip inductor needs to have a three-dimensional spiral coil pattern, and via holes are opened in each layer to ensure electrical continuity in the vertical direction. Laser processing is commonly used as a method for forming via holes, but there are problems in reducing the diameter of the via holes and in terms of cost. To solve this problem, alkali-soluble photosensitive resin compositions have the advantage that vias can be formed by developing with an alkaline aqueous solution after exposure with a photo tool, and that the process costs are lower than with lasers. be.

However, compared with conventional ceramic inductors, chip inductors made of resin materials have problems with dimensional stability (warping) and coating strength during curing because they are resin components. To solve this problem, there is a method of filling the resin component with an inorganic filler. Image quality was difficult to obtain.

Therefore, the object of the present invention is to provide a curable resin composition having excellent adhesion to copper foil and resolution despite the high amount of inorganic filler, a dry film having a resin layer obtained from the composition, An object of the present invention is to provide a cured product of the composition or the resin layer of the dry film, and an electronic component having the cured product.

In general, resolution control is performed by adjusting the type and blending amount of an organic compound (photopolymerizable monomer) having an ethylenically unsaturated group. Therefore, it was difficult to satisfy both of them only by preparing an organic compound having an ethylenically unsaturated group.

As a result of intensive studies aimed at realizing the above object, the present inventors have found that an alkali-soluble resin having an ethylenically unsaturated group is blended as an alkali-soluble resin, and an ethylenically unsaturated group is added to the alkali-soluble resin. The present inventors have found that the above problems can be solved by substantially not blending organic compounds having organic compounds, and by using a liquid epoxy resin, a semi-solid epoxy resin, and a solid epoxy resin in combination, and have completed the present invention.

That is, the curable resin composition of the present invention contains (A) an alkali-soluble resin having an ethylenically unsaturated group, (B) a photopolymerization initiator, (C) an epoxy resin, and (D) an inorganic filler, A curable resin composition in which the amount of the (D) inorganic filler is 50% by mass or more in terms of solid content, and substantially the (A) alkali-soluble resin having an ethylenically unsaturated group and ethylene (C-1) a liquid epoxy resin that is liquid at 20° C., (C-2) that is solid at 20° C., and 40 and (C-3) a solid epoxy resin that is solid at 40°C.

In the curable resin composition of the present invention, the (D) inorganic filler is preferably treated with a surface treatment agent having a curable reactive group.

The curable resin composition of the present invention comprises the total amount of the (C-1) liquid epoxy resin and the (C-2) semi-solid epoxy resin, and the (C-3) solid epoxy resin. The mass ratio is 0.3:1.0 to 2.0:1.0, and the mass ratio of the amount of the (C-1) liquid epoxy resin and the (C-2) semi-solid epoxy resin is A ratio of 0.3:1.0 to 3.0:1.0 is preferred.

In the curable resin composition of the present invention, the (C-1) liquid epoxy resin, the (C-2) semi-solid epoxy resin, and the (C-3) solid epoxy resin are novolak epoxy resins. is preferred.

The curable resin composition of the present invention is preferably used for forming interlayer insulating layers of electronic parts.

The curable resin composition of the present invention is preferably used for forming interlayer insulating layers of inductors.

The dry film of the present invention is characterized by having a resin layer obtained by coating and drying the curable resin composition on the film.

The cured product of the present invention is characterized by being obtained by curing the curable resin composition or the resin layer of the dry film.

The electronic component of the present invention is characterized by having the cured product.

According to the present invention, a curable resin composition having excellent adhesion to a copper foil and excellent resolution despite a large amount of inorganic filler, a dry film having a resin layer obtained from the composition, and the It is possible to provide a cured product of the resin layer of the composition or the dry film, and an electronic component having the cured product.

The curable resin composition of the present invention comprises (A) an alkali-soluble resin having an ethylenically unsaturated group (hereinafter also abbreviated as "(A) alkali-soluble resin"), (B) a photopolymerization initiator, and (C) A curable resin composition comprising an epoxy resin and (D) an inorganic filler, wherein the amount of the (D) inorganic filler is 50% by mass or more in terms of solid content, and substantially the (A) The (C) epoxy resin that does not contain an organic compound having an ethylenically unsaturated group other than an alkali-soluble resin having an ethylenically unsaturated group, (C-1) a liquid epoxy resin that is liquid at 20 ° C. C-2) A semi-solid epoxy resin that is solid at 20°C and liquid at 40°C, and (C-3) a solid epoxy resin that is solid at 40°C. . Since the curable resin composition of the present invention has excellent adhesion to copper foil, even if the copper foil is heat-laminated after development, the adhesion is excellent. Therefore, it is possible to stably and repeatedly laminate the layer of the curable resin composition of the present invention and the layer of copper foil without providing a separate heating step during the formation of the laminated structure. The heating step in the middle can be omitted by collectively heating and final curing later.

Each component of the curable resin composition of the present invention is described below.

[(A) Alkali-soluble resin having an ethylenically unsaturated group]
(A) Alkali-soluble resin is a resin that contains at least one functional group selected from phenolic hydroxyl group, thiol group and carboxyl group and an ethylenically unsaturated group and is developable with an alkaline solution, preferably phenol photosensitive resins having two or more functional hydroxyl groups, carboxyl group-containing photosensitive resins, photosensitive resins having phenolic hydroxyl groups and carboxyl groups, and photosensitive resins having two or more thiol groups. Here, "photosensitive" means having an ethylenically unsaturated group.

(A) The alkali-soluble resin more preferably has a carboxyl group. A carboxyl group-containing photosensitive resin starting from an epoxy resin, a carboxyl group-containing photosensitive resin starting from a phenol compound, a carboxyl group having a copolymer structure A group-containing photosensitive resin and a photosensitive carboxyl group-containing resin having a urethane structure are more preferable. As the ethylenically unsaturated group, those derived from (meth)acrylic acid or (meth)acrylic acid derivatives are preferred. As used herein, (meth)acrylic acid is a generic term for acrylic acid, methacrylic acid and mixtures thereof, and the same applies to other similar expressions.

(A) Specific examples of the alkali-soluble resin include, but are not limited to, compounds (both oligomers and polymers) listed as (1) to (10) below.

(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, etc. , Glycidyl (meth)acrylate, α-methylglycidyl (meth)acrylate, etc. A carboxyl group having a copolymer structure obtained by adding a compound having one epoxy group and one or more (meth)acryloyl groups in the molecule. Contains photosensitive resin. In addition, lower alkyl refers to an alkyl group having 1 to 5 carbon atoms.

(2-1) A carboxyl group-containing urethane resin obtained by a polyaddition reaction of a diisocyanate, a carboxyl group-containing dialcohol compound, and a diol compound, and further containing one epoxy group and one or more (meth ) A carboxyl group-containing photosensitive resin having a urethane structure to which a compound having an acryloyl group is added.
(2-2) Having a urethane structure obtained by reacting a diisocyanate, a carboxyl group-containing dialcohol compound, a diol compound, and a compound having one hydroxyl group and one or more (meth)acryloyl groups in the molecule Carboxyl group-containing photosensitive resin.
(2-3) a urethane structure obtained by reacting a diisocyanate, a carboxyl group-containing dialcohol compound, a diol compound, and a compound having one isocyanate group and one or more (meth)acryloyl groups in the molecule; Carboxyl group-containing photosensitive resin having.
Examples of diisocyanates include aliphatic diisocyanates, branched aliphatic diisocyanates, alicyclic diisocyanates, and aromatic diisocyanates.
Examples of carboxyl group-containing dialcohol compounds include dimethylolpropionic acid and dimethylolbutanoic acid.
Diol compounds include polycarbonate-based polyols, polyether-based polyols, polyester-based polyols, polyolefin-based polyols, acrylic-based polyols, bisphenol A-based alkylene oxide adduct diols, compounds having phenolic hydroxyl groups and alcoholic hydroxyl groups, and the like. be done.
Compounds having one hydroxyl group and one or more (meth)acryloyl groups in the molecule include hydroxyalkyl (meth)acrylates.
Compounds having one isocyanate group and one or more (meth)acryloyl groups in the molecule include an equimolar reaction product of isophorone diisocyanate and pentaerythritol triacrylate.

(3-1) Diisocyanate, (meth)acrylate of bifunctional epoxy resin or its partial acid anhydride-modified product, carboxyl group-containing dialcohol compound, and carboxyl group-containing urethane structure obtained by polyaddition reaction with diol compound Photosensitive resin.
(3-2) A carboxyl having a urethane structure obtained by adding a compound having one epoxy group and one or more (meth)acryloyl groups in the molecule to the carboxyl group-containing photosensitive resin of (3-1). Group-containing photosensitive resin.
(3-3) a diisocyanate, a bifunctional epoxy resin (meth)acrylate or its partial acid anhydride modified product, a carboxyl group-containing dialcohol compound, a diol compound, and one hydroxyl group and one or more in the molecule A carboxyl group-containing photosensitive resin having a urethane structure obtained by reacting with a compound having a (meth)acryloyl group.
(3-4) a diisocyanate, a bifunctional epoxy resin (meth)acrylate or its partial acid anhydride modified product, a carboxyl group-containing dialcohol compound, a diol compound, one isocyanate group in the molecule and one or more A carboxyl group-containing photosensitive resin having a urethane structure obtained by reacting with a compound having a (meth)acryloyl group.

(4) Polyfunctional epoxy resin is reacted with unsaturated monocarboxylic acid such as (meth)acrylic acid, and dibasic acid anhydride such as phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride is added to the hydroxyl group present in the side chain. A carboxyl group-containing photosensitive resin to which a substance is added.

(5) A carboxyl group obtained by reacting an unsaturated group-containing monocarboxylic acid with a polyfunctional epoxy resin obtained by further epoxidizing the hydroxyl group of a bifunctional epoxy resin with epichlorohydrin, and adding a dibasic acid anhydride to the resulting hydroxyl group. Contains photosensitive resin.

(6) 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, and an unsaturated mono Polybasic acid anhydrides such as maleic anhydride, tetrahydrophthalic anhydride, trimellitic anhydride, pyromellitic anhydride, and adipic anhydride are added to the alcoholic hydroxyl groups of the reaction product obtained by reacting with a carboxylic acid. A carboxyl group-containing photosensitive resin obtained by reacting

(7) A polyfunctional oxetane resin is reacted with a dicarboxylic acid, and a dibasic acid anhydride is added to the resulting primary hydroxyl group to form a carboxyl group-containing polyester resin. ) A carboxyl group-containing photosensitive resin obtained by adding a compound having one epoxy group and one or more (meth)acryloyl groups in the molecule such as acrylate.

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

(9) Obtained by reacting a reaction product obtained by reacting a compound having multiple 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.

(10) A compound obtained by further adding a compound having one epoxy group and one or more (meth)acryloyl groups in the molecule as described above to the carboxyl group-containing photosensitive resins of (4) to (9) above. Carboxyl group-containing photosensitive resin.

(A) The acid value of the alkali-soluble resin is desirably in the range of 20-200 mgKOH/g, more preferably in the range of 40-150 mgKOH/g. (A) When the acid value of the alkali-soluble resin is 20 mgKOH/g or more, the adhesion of the coating film is good, and alkali development is good when it is made into a photocurable resin composition. On the other hand, if the acid value is 200 mgKOH/g or less, the dissolution of the exposed area by the developer can be suppressed, so the opening may become larger than necessary, and in some cases, the exposed area and the unexposed area may be developed without distinction. It is possible to satisfactorily draw a resist pattern by suppressing dissolution and peeling with a liquid.

As the alkali-soluble resin (A), the carboxyl group-containing photosensitive resins (4) to (10) are preferable, and from the viewpoint of HAST resistance, the carboxyl group-containing photosensitive resins (8) and (9) are more preferable.

The weight-average molecular weight of (A) the alkali-soluble resin varies depending on the resin skeleton, but is preferably in the range of 1,500 to 50,000, more preferably 1,500 to 30,000. When the weight-average molecular weight is 1,500 or more, the tack-free property is good, the moisture resistance of the coating film after exposure is good, the film reduction during development is suppressed, and the deterioration of resolution can be further suppressed. On the other hand, when the weight average molecular weight is 50,000 or less, the developability is good and the storage stability is also excellent.

(A) The double bond equivalent of the alkali-soluble resin is, for example, 500 to 3,500 g/eq. , and from the viewpoint of resolution, 700 to 3,000 g/eq. is preferred.

(A) Alkali-soluble resins may be used alone or in combination of two or more. (A) The content of the alkali-soluble resin is, for example, 5 to 30% by mass based on the total solid content of the composition.

Moreover, the curable resin composition of the present invention may contain a conventionally known alkali-soluble resin having no ethylenically unsaturated groups within a range that does not impair the effects of the present invention.

[(B) Photoinitiator]
The curable resin composition of the present invention contains (B) a photopolymerization initiator. (B) As the photopolymerization initiator, any known one can be used. (B) A photoinitiator may be used individually by 1 type, and may be used in combination of 2 or more type.

Specific examples of the (B) photopolymerization initiator include bis-(2,6-dichlorobenzoyl)phenylphosphine oxide and 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)phenyl Phosphine oxide, bis-(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, bis-(2,6-dimethoxybenzoyl)-2,5-dimethylphenylphosphine oxide, bis- bisacylphosphine oxides such as (2,4,6-trimethylbenzoyl)-phenylphosphine oxide; 2,6-dimethoxybenzoyldiphenylphosphine oxide, 2,6-dichlorobenzoyldiphenylphosphine oxide, 2,4, Monoacylphosphine oxides such as 6-trimethylbenzoylphenylphosphinic acid methyl ester, 2-methylbenzoyldiphenylphosphine oxide, pivaloylphenylphosphinic acid isopropyl ester, and 2,4,6-trimethylbenzoyldiphenylphosphine oxide ; ethyl phenyl (2,4,6-trimethylbenzoyl)phosphinate, 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 benzophenones such as benzophenone, p-methylbenzophenone, Michler's ketone, methylbenzophenone, 4,4′-dichlorobenzophenone, and 4,4′-bisdiethylaminobenzophenone; acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2, 2-diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 1-hydroxycyclohexylphenyl ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-1-propanone, 2-benzyl- 2-dimethylamino-1-(4-morpholinophenyl)-butanone-1,2-(dimethylamino)-2-[(4-methylphenyl)methyl)-1-[4-(4-morpholinyl)phenyl] -Acetophenones such as 1-butanone and N,N-dimethylaminoacetophenone; thioxanthones such as 4-diisopropylthioxanthone; anthraquinones such as anthraquinone, chloroanthraquinone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 1-chloroanthraquinone, 2-amylanthraquinone, and 2-aminoanthraquinone; ketals such as acetophenone dimethyl ketal and benzyl dimethyl ketal; benzoic acid esters such as ethyl-4-dimethylaminobenzoate, 2-(dimethylamino)ethyl benzoate and p-dimethylbenzoic acid ethyl ester; 1-[4-(phenylthio)-,2-(O-benzoyloxime)], ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, 1- Oxime esters such as (O-acetyloxime); 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-pyr-1-yl)ethyl)phenyl]titanium; phenyl disulfide 2-nitrofluorene, butyroin, Anisoin ethyl ether, azobisisobutyronitrile, tetramethylthiuram disulfide and the like can be mentioned. Among the photopolymerization initiators, it is preferable to contain any one of acetophenones and acylphosphine oxides, and since the resolution and adhesion to the copper foil are further improved, the acylphosphine oxides are included. is more preferable.

The amount of the photopolymerization initiator (B) is, for example, 5 to 30 parts by mass with respect to 100 parts by mass of the alkali-soluble resin (A).

[(C) epoxy resin]
The curable resin composition of the present invention comprises (C) an epoxy resin, (C-1) a liquid epoxy resin that is liquid at 20°C, and (C-2) a solid at 20°C and a liquid at 40°C. Some semi-solid epoxy resins and (C-3) solid epoxy resins that are solid at 40°C. Here, the determination of the liquid state is carried out in accordance with the "Confirmation method of the liquid state" in Attachment No. 2 of the Ministerial Ordinance on the Test and Properties of Hazardous Substances (Ministry of Home Affairs Ordinance No. 1 of 1989). For example, the method described in paragraphs 23 to 25 of JP-A-2016-079384 is used.

(C-1) Liquid epoxy resins include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AF type epoxy resin, phenol novolac type epoxy resin, tert-butyl-catechol type epoxy resin, glycidylamine type epoxy resin, Examples include aminophenol type epoxy resins and alicyclic epoxy resins. Among the liquid epoxy resins (C-1), bisphenol A type epoxy resins and novolak type epoxy resins are preferred. Further, among the liquid epoxy resins (C-1), novolac type epoxy resins are more preferable from the viewpoint of adhesion to the copper foil.

The (C-1) liquid epoxy resin may be used alone or in combination of two or more.

(C-2) Semi-solid epoxy resins include EPICLON860, EPICLON 900-IM, EPICLON EXA-4816, EPICLON EXA-4822 manufactured by DIC, Epotote YD-134 manufactured by Tohto Kasei Co., Ltd., jER834 and jER872 manufactured by Mitsubishi Chemical, Sumitomo Bisphenol A type epoxy resins such as ELA-134 manufactured by Kagaku Co.; naphthalene type epoxy resins such as EPICLON HP-4032 manufactured by DIC Corporation; and phenol novolac type epoxy resins such as EPICLON N-740 manufactured by DIC Corporation. (C-2)) Of the semi-solid epoxy resins, bisphenol A type epoxy resins and novolak type epoxy resins are preferred. Further, (C-2)) among the semi-solid epoxy resins, the novolak type epoxy resin is preferable from the viewpoint of adhesion to the copper foil.

The (C-2) semi-solid epoxy resin may be used alone or in combination of two or more.

(C-3) Solid epoxy resins include naphthalene-type epoxy resins such as EPICLON HP-4700 (naphthalene-type epoxy resin) manufactured by DIC and NC-7000 (naphthalene skeleton-containing polyfunctional solid epoxy resin) manufactured by Nippon Kayaku; EPPN-502H (trisphenol epoxy resin) manufactured by Nippon Kayaku Co., Ltd., an epoxidized product (trisphenol type epoxy resin) of a condensation product of a phenol and an aromatic aldehyde having a phenolic hydroxyl group; EPICLON HP-7200H manufactured by DIC ( Dicyclopentadiene aralkyl type epoxy resin such as dicyclopentadiene skeleton-containing polyfunctional solid epoxy resin); Nippon Kayaku Co., Ltd. NC-3000H (biphenyl skeleton-containing polyfunctional solid epoxy resin) and other biphenyl aralkyl type epoxy resins; Nippon Kayaku Biphenyl/phenol novolak type epoxy resins such as NC-3000L manufactured by DIC Corporation; Novolac type epoxy resins such as EPICLON N660, EPICLON N690 manufactured by DIC Corporation, and EOCN-104S manufactured by Nippon Kayaku; Biphenyl type such as YX-4000 manufactured by Mitsubishi Chemical Co., Ltd. Epoxy resins; phosphorus-containing epoxy resins such as TX0712 manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.; tris(2,3-epoxypropyl) isocyanurate such as TEPIC manufactured by Nissan Chemical Industries; (C-3) Among the solid epoxy resins, preferred are dicyclopentadiene type epoxy resins, naphthalene type epoxy resins, biphenyl type epoxy resins, and novolac type epoxy resins. Further, among (C-3) solid epoxy resins, novolac type epoxy resins are preferable from the viewpoint of copper foil adhesion.

(C-3) The solid epoxy resin may be used alone or in combination of two or more.

In the present invention, the (C-1) liquid epoxy resin, the (C-2) semi-solid epoxy resin, and the (C-3) solid epoxy resin are novolak type epoxy resins to improve copper foil adhesion. It is preferable because it is excellent in

In the present invention, the mass ratio of the total amount of (C-1) liquid epoxy resin and (C-2) semi-solid epoxy resin to the amount of (C-3) solid epoxy resin is 0.3:1. .0 to 2.0:1.0, and the mass ratio of the blending amount of (C-1) liquid epoxy resin and (C-2) semi-solid epoxy resin is 0.3:1.0 to 3.0: 1.0 is preferred. Within such a range, the adhesion to the copper foil and the resolution are further improved.

(C) The amount of the epoxy resin compounded is preferably 0.6 to 2.5 equivalents of the epoxy group with respect to 1 equivalent of the alkali-soluble group such as the carboxyl group or phenolic hydroxyl group of the alkali-soluble resin (A). .

The curable resin composition of the present invention may contain thermosetting components other than (C) the epoxy resin within a range that does not impair the effects of the present invention.

[(D) inorganic filler]
The curable resin composition of the present invention contains (D) an inorganic filler in an amount of 50% by mass or more in terms of solid content. (D) An inorganic filler may be used individually by 1 type, and may be used in combination of 2 or more type. In addition, (D) the inorganic filler is preferably a surface-treated filler (surface-treated filler), so that a cured product with higher elasticity and lower CTE can be obtained without impairing resolution.
Here, (D) the surface treatment of the inorganic filler means a treatment for improving compatibility with (A) an alkali-soluble resin having an ethylenically unsaturated group or (C) an epoxy resin. The surface treatment of the (D) inorganic filler is not particularly limited, but the (D) inorganic filler is preferably treated with a surface treatment agent having a curable reactive group. By reducing the interface between the two, the elastic modulus can be increased and the strength of the coating film can be improved.

(D) Examples of inorganic fillers include silica, barium sulfate, barium titanate, Neuburg silica, talc, clay, magnesium carbonate, calcium carbonate, aluminum oxide, titanium oxide, aluminum hydroxide, silicon nitride, and aluminum nitride. mentioned. Among them, silica is preferable, and it can suppress curing shrinkage of the cured product of the curable resin composition and improve properties such as adhesion and hardness. Examples of silica include fused silica, spherical silica, amorphous silica, and crystalline silica.

The surface-treated filler is preferably an inorganic filler surface-treated with a coupling agent.
As the coupling agent, silane-based, titanate-based, aluminate-based, and zirco-aluminate-based coupling agents can be used. Among them, silane coupling agents are preferred. Examples of such silane coupling agents include vinyltrimethoxysilane, vinyltriethoxysilane, N-(2-aminomethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-amino propyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-anilinopropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2-(3,4-epoxy Cyclohexyl)ethyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane and the like can be mentioned, and these can be used alone or in combination. These silane-based coupling agents are preferably immobilized in advance on the surface of the inorganic filler by adsorption or reaction. In the present invention, the coupling agent applied to the inorganic filler is not included in the "organic compound having an ethylenically unsaturated group".

The surface-treated filler preferably has a curable reactive group. 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, it is preferable to have an ethylenically unsaturated group such as a vinyl group, a styryl group, a methacrylic group, an acrylic group, or an epoxy group, so that a curable resin composition having more excellent resolution can be obtained. More preferably, the surface-treated filler is silica having an ethylenically unsaturated group or an epoxy group.

(D) The inorganic filler preferably has an average particle size of 5 μm or less, more preferably 0.4 to 1.0 μm. Here, the average particle size is the average particle size of the inorganic filler alone or the inorganic filler dispersion. A nanofiller having an average particle size of 100 nm or less may also be used in combination. Here, in the present specification, the average particle size of the inorganic filler is not only the particle size of the primary particles, but also the average particle size (D50) including the particle size of the secondary particles (aggregate), and is measured by a laser diffraction method. is the value of D50 measured by Microtrac MT3300EXII manufactured by Microtrac Bell Co., Ltd. can be used as a measuring device using the laser diffraction method.

The inorganic filler (D) may have an average particle size adjusted, and is preferably pre-dispersed with a bead mill or a jet mill, for example. In addition, the inorganic filler (D) is preferably blended in a slurry state. By blending in a slurry state, high dispersion is easily achieved, aggregation is prevented, and handling is facilitated.

The curable resin composition of the present invention has excellent adhesion to copper foil and resolution even when (D) is highly filled with an inorganic filler, and when highly filled with (D) an inorganic filler, when cured (D) The inorganic filler may be added in an amount of, for example, 60% by mass or more in terms of solid content, because the dimensional stability (low warpage) and coating strength of the (D) inorganic filler are excellent.

The amount of the inorganic filler (D) to be blended is preferably in the range of 50 to 75% by mass in terms of the solid content of the curable resin composition from the viewpoint of securing the rigidity of the cured film and obtaining better resolution.

(Organic compound having an ethylenically unsaturated group)
The curable resin composition of the present invention does not substantially contain an organic compound having an ethylenically unsaturated group other than (A) the alkali-soluble resin having an ethylenically unsaturated group. Examples of organic compounds having an ethylenically unsaturated group include acrylate compounds that are blended in conventional curable resin compositions as photoreactive monomers.

Here, "substantially does not contain" means that it is not actively blended as a constituent component, and it is not excluded that it is contained in a small amount within a range that does not impair the effects of the present invention. For example, it is 3 parts by mass or less, preferably 1 part by mass or less per 100 parts by mass of the alkali-soluble resin (A), and most preferably does not contain an organic compound having an ethylenically unsaturated group. The smaller the content of the organic compound having an ethylenically unsaturated group, the better the resolution and copper foil adhesion.

(Curing accelerator)
The curable resin composition of the present invention preferably contains a curing accelerator. Examples of such curing accelerators include 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 as a curing accelerator is used. A hardening accelerator may be used individually by 1 type, and may be used in combination of 2 or more type.

The content of the curing accelerator is preferably 0.1 to 20 parts by mass per 100 parts by mass of the alkali-soluble resin (A).

(Organic solvent)
In the curable resin composition of the present invention, (A) an organic solvent may be used for synthesizing an alkali-soluble resin, preparing the composition, or adjusting the viscosity for application to a substrate or carrier film. can. Examples of organic solvents include ketones, aromatic hydrocarbons, glycol ethers, glycol ether acetates, esters, alcohols, aliphatic hydrocarbons, and petroleum solvents. More specifically, 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, glycol ethers such as dipropylene glycol monomethyl ether, dipropylene glycol diethyl ether, triethylene glycol monoethyl ether; ethyl acetate, butyl acetate, diethylene glycol monoethyl ether acetate, dipropylene glycol methyl ether acetate, propylene glycol methyl ether acetate , propylene glycol ethyl ether acetate, propylene glycol butyl ether acetate; alcohols such as ethanol, propanol, ethylene glycol, propylene glycol; aliphatic hydrocarbons such as octane and decane; petroleum ether, petroleum naphtha, hydrogenated petroleum naphtha and petroleum solvents such as solvent naphtha. An organic solvent may be used individually by 1 type, and may be used in combination of 2 or more type.

(Other optional ingredients)
The curable resin composition of the present invention may optionally further contain a colorant, a photoinitiation aid, a cyanate compound, an elastomer, a mercapto compound, a urethanization catalyst, a thixotropic agent, an adhesion promoter, a block copolymer, Magnetic particles, chain transfer agents, polymerization inhibitors, copper damage inhibitors, antioxidants, rust inhibitors, UV absorbers, fine powder silica, organic bentonite, thickeners such as montmorillonite, silicone-based, fluorine-based, acrylic-based , polymer-based antifoaming agents and / or leveling agents, imidazole-based, thiazole-based, triazole-based silane coupling agents, phosphinates, phosphate ester derivatives, phosphazene compounds and other phosphorus compounds, etc. Ingredients can be blended. As these, those known in the field of electronic materials can be used.

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. In the case of a dry film, the dried resin layer is excellent in film thickness accuracy, and excellent in dimensional accuracy when laminating the multilayer chip capacitor. 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 appropriately within the range of 3 to 150 μm, preferably 5 to 60 μm, in terms of film 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, as the film to which the curable resin composition of the present invention is applied when producing the dry film in the present invention, either a carrier film or a cover film may be used.

The electronic component of the present invention has the curable resin composition of the present invention or a cured product obtained by curing the resin layer of the dry film. As a method for forming a resin layer using the curable resin composition 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 the substrate is coated. After coating by a method such as dip coating, flow coating, roll coating, bar coating, screen printing, curtain coating, etc., the organic solvent contained in the composition is removed at a temperature of 60 to 100 ° C. A tack-free resin layer is formed by volatilizing and drying (temporary drying). 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.

The substrate is not particularly limited, but in addition to printed wiring boards and flexible printed wiring boards on which a circuit is formed in advance with copper or the like, paper phenol, paper epoxy, glass cloth epoxy, glass polyimide, glass cloth/non-woven cloth epoxy, Materials such as glass cloth/paper epoxy, synthetic fiber epoxy, fluorine resin/polyethylene/polyphenylene ether, polyphenylene oxide/cyanate, copper-clad laminates for high-frequency circuits, etc. All grades (FR-4, etc.) ), metal substrates, polyimide films, PET films, polyethylene naphthalate (PEN) films, glass substrates, ferrite sheets, dielectric ceramic substrates, and wafer plates.

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.

As an example of the method of manufacturing the electronic component of the present invention, an example of the method of manufacturing an inductor having an interlayer insulating layer formed using the resin layer of the dry film of the present invention will be described below. The resin layer of the dry film of the present invention is laminated on a base material having a conductive pattern such as copper, and after forming the resin layer on the base material, the resin layer is exposed and developed to provide an interlayer conductive part. Form a via. Here, the carrier film may be peeled off either before or after exposure. Next, the via is filled with a conductor to provide an interlayer conductive portion. The method of filling the conductor is not particularly limited, and for example, the conductor may be filled into the via by a known and commonly used method such as filling of metal paste by paste printing, electroplating, or etching of copper foil. Next, after laminating a copper foil on the resin layer while heating, a conductor pattern of the copper foil is formed by etching. By repeating the above process and finally by collectively heat-curing, it is possible to manufacture an inductor having a three-dimensional spiral conductor coil pattern.

The exposure and development are performed by selectively exposing to active energy rays through a photomask having a predetermined pattern, and developing the unexposed area with a dilute alkaline aqueous solution (eg, 0.3 to 3% by mass aqueous solution of sodium carbonate). form a pattern.

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.

Although the lamination of the copper foil is not particularly limited, for example, lamination may be performed while heating at 40 to 120.degree.

The heat curing is not particularly limited, but for example, it may be heated at 130 to 220 ° C., and heat curing after irradiation with active energy rays, or irradiation with active energy rays after heat curing, or final finish curing only by heat curing ( main curing).

A protective layer for the inductor may also be provided. Although the protective layer is not particularly limited, for example, protective layers may be provided on both end surfaces in the stacking direction. In addition, the protective layer may be a cured product of the curable resin composition of the present invention, and by forming a cured product of the same composition, it is possible to reduce the influence of differences in thermophysical properties.

The curable resin composition of the present invention can be suitably used for the production of electronic parts, and is useful in electronic parts used in various electronic devices such as digital equipment, AV equipment, and information communication terminals. The electronic component may be passive or active, preferably an inductor. In particular, the curable resin composition of the present invention is excellent in adhesion to copper foil and resolution, so that it can be suitably used for forming an interlayer insulation layer of electronic components, and can be used for interlayer insulation of laminated electronic components. It can be preferably used to form a layer, particularly an interlayer insulating layer of an inductor. Although the size of the inductor is not particularly limited, it can be suitably used for manufacturing a small inductor with one side of 10 mm or less due to its excellent resolution.

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.

(Synthesis of alkali-soluble resin A-1 having ethylenically unsaturated groups)
An autoclave equipped with a thermometer, a nitrogen introduction device and an alkylene oxide introduction device, and a stirring device was charged with a novolak cresol resin (manufactured by Showa Polymer Co., Ltd., trade name "Shonol CRG951", OH equivalent: 119.4). 4 g of potassium hydroxide, 1.19 g of potassium hydroxide, and 119.4 g of toluene were charged, and the inside of the system was replaced with nitrogen while stirring, and the temperature was raised. Next, 63.8 g 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 g of 89% phosphoric acid was added to and mixed with the reaction solution to neutralize potassium hydroxide. A propylene oxide reaction solution of a novolak-type cresol resin was obtained. This was obtained by adding an average of 1.08 mol of alkylene oxide per equivalent of phenolic hydroxyl group.
Next, 293.0 g of the alkylene oxide reaction solution of the novolak type cresol resin obtained, 43.2 g of acrylic acid, 11.53 g of methanesulfonic acid, 0.18 g of methylhydroquinone and 252.9 g of toluene were mixed with a stirrer, a thermometer and air. The mixture was charged into a reactor equipped with a blowing tube, air was blown in at a rate of 10 ml/min, and the mixture was reacted at 110° C. for 12 hours while stirring. 12.6 g of water was distilled out as an azeotrope with toluene, which was produced by the reaction. After cooling to room temperature, the resulting reaction solution was neutralized with 35.35 g 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 g of diethylene glycol monoethyl ether acetate to obtain a novolac type acrylate resin solution. Next, 332.5 g of the obtained novolak-type acrylate resin solution and 1.22 g of triphenylphosphine were charged into a reactor equipped with a stirrer, a thermometer and an air blowing pipe, and air was blown at a rate of 10 ml/min. While stirring, 60.8 g of tetrahydrophthalic anhydride was gradually added and reacted at 95-101° C. for 6 hours. A resin solution A-1 of a carboxyl group-containing photosensitive resin having a solid acid value of 88 mgKOH/g and a non-volatile content of 65% was obtained.

(Preparation of inorganic filler)
(Preparation of silica surface-treated with methacrylsilane)
Dispersion treatment was performed using 700 g of Admatec spherical silica, 300 g of PMA (propylene glycol monomethyl ether acetate) as a solvent, and 0.7 μm zirconia beads in a bead mill. This was repeated three times and filtered through a 3 μm filter to prepare a silica slurry having an average particle size of 0.7 μm.
Using the silica slurry having an average particle size of 0.7 μm obtained above (solid content of 70% by mass in PMA (propylene glycol monomethyl ether acetate)), 4% by weight of methacrylsilane is added to the silica, and a bead mill is used. After treatment for 10 minutes, silica surface-treated with methacrylsilane was obtained. As the methacrylsilane, KBM-503 manufactured by Shin-Etsu Silicone Co., Ltd. was used.

(Preparation of silica surface-treated with epoxysilane)
A silica slurry having an average particle size of 0.7 μm obtained in the same manner as above (in PMA (propylene glycol monomethyl ether acetate), solid content 70% by mass)) was used, and 4% by weight of epoxysilane was added to the silica. , for 10 minutes in a bead mill to obtain silica surface-treated with epoxysilane. As the epoxysilane, KBM-403 manufactured by Shin-Etsu Silicone Co., Ltd. was used.

[Examples 1 to 15, Comparative Examples 1 to 8]
Each component was blended according to the formulations shown in Tables 1 to 4 below, premixed with a stirrer, and then dispersed with a bead mill to prepare a curable resin composition. The compounding amount in the table indicates parts by mass. The prepared curable resin compositions of Examples and Comparative Examples were evaluated as follows.

<Preparation of dry film>
After appropriately diluting the curable resin compositions of Examples 1 to 15 and Comparative Examples 1 to 8 with methyl ethyl ketone, using an applicator, apply to a PET film (manufactured by Toray Industries, FB-50: 16 μm), 80 ° C. and dried for 30 minutes to obtain a dry film. The film thickness of the resin layer after drying was adjusted according to the type of applicator used, and dry films having different film thicknesses were produced depending on the evaluation items.

<Evaluation board manufacturing method>
After producing a dry film by the above method (thickness of the resin layer 20 μm), a printed wiring board on which a circuit of line/space = 25 μm/25 μm is formed, or a copper clad laminate without a circuit pattern (copper solid substrate) ) was chemically polished, then a vacuum laminator (Nikko Materials CVP-300) was used to pressurize: 0.4 MPa, 100° C., 1 minute, vacuum: 133.3 Pa, heat laminate at 100° C., After flat pressing at 5 kg/f, a substrate having an unexposed photosensitive resin layer (dry film) was obtained.

<Lamination property>
Laminatability was evaluated according to the following criteria using a circuit portion of line/space=25 μm/25 μm of the substrate obtained by the substrate manufacturing method described above.
◯: No bubbles were generated between the circuits, lamination was possible, and sufficient smoothness was obtained by observation of the cross section of the circuit portion.
x: Bubbles are generated between circuits, or the flow property is insufficient, and smoothness cannot be obtained by cross-sectional observation of the circuit portion.

<Copper foil adhesion>
A photosensitive resin layer on a copper solid substrate (150 mm × 95 mm) obtained under the above substrate manufacturing conditions (film thickness of resin layer 15 μm) was exposed at 300 mJ/cm ² () using Oak Manufacturing UV-DI exposure machine (Mms-60). Exposure was carried out with a step tablet 8/41 steps). Five minutes after the exposure, the PET film was peeled off to obtain a resin layer that was entirely exposed. After that, development is performed for 90 seconds with a 1 wt% Na ₂ CO ₃ aqueous solution at 30° C. under conditions of a spray pressure of 2 kg/cm ² , and the matte surface of electrolytic copper foil manufactured by Furukawa Electric Co., Ltd. (product name: F2-WS) is placed on the resin layer. , Using a vacuum laminator (Nikko Materials CVP-300), pressure: 0.4 MPa, 100 ° C., 1 minute, vacuum: 133.3 Pa Heat lamination, 120 ° C., flat press at 5 kg / f and attached the copper foil. After cutting the pasted substrate into a width of 2 cm and a length of 9.5 cm, the copper foil is peeled off leaving a width of 1 cm. Using a tensile tester (AGS-100) manufactured by Shimadzu Corporation, the remaining 1 cm wide copper foil was peeled off from the end face, and the copper foil adhesion was evaluated according to the following criteria.
◎: Peeling strength is 2 N / cm or more ○: Peeling strength is 1 N / cm or more and less than 2 N / cm ×: Peeling strength is less than 1 N / cm

<Resolution>
A pattern in which the photosensitive resin layer on the copper solid substrate obtained under the above substrate manufacturing conditions (film thickness of the resin layer is 15 μm) is opened in increments of 10 μm with a diameter of 30 to 80 μm using a UV-DI exposure machine (Mms-60) from Oak Manufacturing. was used, and exposure was performed at an exposure amount of 300 mJ/cm ² . Five minutes after the exposure, the PET film was peeled off, and then developed with a 1 wt % Na ₂ CO ₃ aqueous solution at 30° C. under conditions of a spray pressure of 2 kg/cm ² for 90 seconds. After that, it was irradiated with ultraviolet rays in a UV conveyor furnace under the condition of an accumulated exposure amount of 1000 mJ/cm ² , and then cured by heating at 170° C. for 60 minutes. The resulting openings were observed (scanning electron microscope) and evaluated according to the following criteria.
A: The bottom diameter of the opening pattern of 30 μmφ is 90 to 100% of the top diameter.
◯: The bottom diameter of the opening pattern of 30 μmφ is 80% to less than 90% of the top diameter.
x: The bottom diameter of the opening pattern of 30 μmφ is less than 80% of the top diameter.

<Warp>
After producing a dry film (thickness of the resin layer: 15 μm) by the above method, the dry film is placed on the glossy surface of Furukawa Electric Co., Ltd.'s electrolytic copper foil (product name: FV-WS), and a vacuum laminator (Nikko Materials' CVP -300), pressurization: 0.4 MPa, 100 ° C., 1 minute, degree of vacuum: 133.3 Pa Heat lamination, flat press at 100 ° C., 5 kg / f, and affixed to copper foil . This copper foil was irradiated with ultraviolet rays in a UV conveyor furnace under the condition of an accumulated exposure amount of 1000 mJ/cm ² and then heated at 170° C. for 60 minutes to cure the resin layer. After curing, a piece of 5 cm×5 cm was cut out, and the amount of warpage on each of the four sides was measured and evaluated according to the following criteria.
◎: The average value of the warp amount on the 4 sides is less than 4 mm ○: The average value of the warp amount on the 4 sides is 4 mm or more and less than 7 mm ×: The average value of the warp amount on the 4 sides is 7 mm or more

<Paint film strength (flexural modulus)>
After producing a dry film (thickness of the resin layer: 20 μm) by the above method, the dry film is placed on the glossy surface of Furukawa Electric Co., Ltd.'s electrolytic copper foil (product name: FV-WS), and a vacuum laminator (Nikko Materials' CVP -300), pressurization: 0.4 MPa, 100 ° C., 1 minute, degree of vacuum: 133.3 Pa Heat lamination, flat press at 100 ° C., 5 kg / f, and affixed to copper foil . Repeat this twice to prepare a coating film with a thickness of 40 μm, and after exposure with an exposure amount of 300 mJ / cm ² with a UV-DI exposure machine (Mms-60) from Oak Works, repeat this three times to obtain a coating film with a thickness of about 120 μm. formed.
After that, it was irradiated with ultraviolet rays in a UV conveyor furnace under the condition of an accumulated exposure amount of 1000 mJ/cm ² , and then cured by heating at 170° C. for 60 minutes. The cured coating film was peeled off from the copper foil, cut into a size of 10 mm × 100 mm, and measured with a tensile tester (AGS-100) manufactured by Shimadzu Corporation under the conditions of a distance between fulcrums of 20 mm and a compression rate of 2 mm / min. , was evaluated according to the following criteria.
◎: bending elastic modulus is 10 GPa or more ○: bending elastic modulus is 5 GPa or more and less than 10 GPa ×: breaking strength is less than 5 GPa

*1: Carboxyl group-containing resin A-1 having an ethylenically unsaturated group synthesized above
*2: Omnirad TPO (2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide) manufactured by IGM Resins
*3: Omnirad 907 (2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one) manufactured by IGM Resins
*4: EPICLON N-730A manufactured by DIC (phenol novolac type epoxy resin)
*5: EPICLON 840-S manufactured by DIC (Bisphenol A type epoxy resin)
*6: EPICLON N-740 manufactured by DIC (phenol novolac type epoxy resin)
*7: EPICLON 860 manufactured by DIC (Bisphenol A type epoxy resin)
*8: EPICLON N-770 manufactured by DIC (phenol novolac type epoxy resin, softening point 70°C)
* 9: EPICLON N-870 manufactured by DIC (bisphenol A novolac type epoxy resin, softening point 70 ° C.)
* 10: Nippon Kayaku NC-7300L (naphthalene type epoxy resin, softening point 63 ° C.)
*11: Silica surface-treated with methacrylsilane prepared above *12: Silica surface-treated with epoxysilane prepared above *13: SO-C2 manufactured by Admatechs
* 14: Nippon Kayaku DPHA (dipentaerythritol hexaacrylate)
*15: BYK-361N (acrylate leveling agent) manufactured by BYK-Chemie Japan
*16: C.I. I. Pigment Yellow 147
*17: Propylene glycol monomethyl ether acetate

From the results shown in the above table, the curable resin compositions of Examples 1 to 15 of the present invention are excellent in adhesion to copper foil and resolution, despite the large amount of inorganic filler. Recognize.

Claims (9)

(A) an alkali-soluble resin having an ethylenically unsaturated group;
(B) a photoinitiator,
(C) an epoxy resin, and
A curable resin composition comprising (D) an inorganic filler, wherein the amount of the (D) inorganic filler is 50% by mass or more in terms of solid content,
An organic compound having an ethylenically unsaturated group in addition to the (A) alkali-soluble resin having an ethylenically unsaturated group (wherein the (D) inorganic filler is a surface treatment agent having a curable reactive group). If it is treated, it does not contain the surface treatment agent having the curable reactive group) ,
As the (C) epoxy resin, (C-1) a liquid epoxy resin that is liquid at 20° C., (C-2) a semi-solid epoxy resin that is solid at 20° C. and liquid at 40° C., and ( C-3) A curable resin composition comprising a solid epoxy resin that is solid at 40°C. 2. The curable resin composition according to claim 1, wherein the inorganic filler (D) is treated with a surface treatment agent having a curable reactive group. The mass ratio of the total amount of the liquid epoxy resin (C-1) and the semi-solid epoxy resin (C-2) to the solid epoxy resin (C-3) was 0.3:1. 0 to 2.0:1.0,
The mass ratio of the (C-1) liquid epoxy resin and the (C-2) semi-solid epoxy resin is 0.3:1.0 to 3.0:1.0. The curable resin composition according to claim 1 or 2. Claims 1 to 3, wherein the (C-1) liquid epoxy resin, the (C-2) semi-solid epoxy resin, and the (C-3) solid epoxy resin are novolac type epoxy resins. Curable resin composition according to any one of. 5. The curable resin composition according to any one of claims 1 to 4, which is used for forming interlayer insulating layers of electronic parts. 6. The curable resin composition according to claim 5, which is used for forming an interlayer insulating layer of an inductor. A dry film comprising a resin layer obtained by applying the curable resin composition according to any one of claims 1 to 6 to a film and drying the composition. A cured product obtained by curing the curable resin composition according to any one of claims 1 to 6 or the resin layer of the dry film according to claim 7. An electronic component comprising the cured product according to claim 8 .