JP2019178304A - Curable resin composition, dry film, cured product and printed wiring board - Google Patents

Abstract

To provide a curable resin composition having excellent B-HAST resistance and PCT resistance while ensuring excellent reliability as a cured product such as high rigidity and excellent TCT resistance, and a dry film, cured product and printed wiring board including the same.SOLUTION: The present invention provides a curable resin composition containing (A) a carboxyl group-containing resin, (B) an epoxy resin having a dicyclopentadiene skeleton, (C) a photopolymerization initiator, (D) spherical silica, where a content of the (D) spherical silica is 50 mass% or more in a nonvolatile component of the composition. There are also provided a dry film, cured product and printed wiring board including the same.SELECTED DRAWING: None

Description

  The present invention relates to a curable resin composition (hereinafter also simply referred to as “composition”), a dry film, a cured product, and a printed wiring board.

Conventionally, as a material for forming a permanent film such as a solder resist on a printed wiring board by exposure and development, a curable resin composition that can be developed with an alkaline aqueous solution has been used.
On the other hand, in response to the increase in the density of printed wiring boards as electronic devices become lighter and thinner, semiconductor packages have become smaller and more pins have been put into practical use and mass production has progressed. Recently, QFP (Quad Flat Flat) has been developed. Instead of semiconductor packages called packages) or SOP (small outline packages), semiconductor packages such as BGA (ball grid array) and CSP (chip scale packages) using package substrates are adopted. It has become to.
In such a package substrate, since the wiring patterns are formed with higher density and close to each other, a permanent film such as a solder resist used for the package substrate has high reliability (insulation reliability (B-HAST). Resistance), high temperature humidification resistance (PCT resistance), cooling cycle resistance (TCT resistance), heat resistance, and the like) have been demanded.

  As a method for imparting high reliability to such a solder resist for package substrates, for example, it is generally performed to improve characteristics such as rigidity by highly filling an inorganic filler in a curable resin composition. It has been broken. Among these inorganic fillers, especially spherical silica is widely used for improving the rigidity of the solder resist and improving the TCT resistance because of its excellent filling property and low coefficient of thermal expansion (CTE) (see Patent Document 1). .

JP 2014-81611 A

  However, when an inorganic filler such as spherical silica is highly filled in the curable resin composition, there is a new problem that the B-HAST resistance and PCT resistance of the cured product deteriorate.

  Therefore, the object of the present invention is to ensure excellent reliability as a cured product such as high rigidity and excellent TCT resistance even if highly filled with an inorganic filler such as spherical silica in the curable resin composition, It is in providing the curable resin composition which is excellent in B-HAST tolerance and PCT tolerance, a dry film using this, a hardened | cured material, and a printed wiring board.

The inventors paid attention to spherical silica excellent in high filling property, and conducted earnest studies for realizing the above-mentioned object. As a result, when the inventors highly charged spherical silica into the curable resin composition, the amount of the resin component decreased, and the water absorption as a cured product decreased, while B-HAST resistance and PCT I noticed that tolerance tends to get worse. The inventors have intensively studied the cause, and when the spherical resin is highly filled in the curable resin composition, moisture easily penetrates into the resin from the surface of the cured product through the interface between the inorganic filler and the resin. It was newly found that the ester bond of the resin in the cured product causes hydrolysis.
Then, based on such a cause, paying attention to the chemical structure of the epoxy resin which is a curable component of the composition, further intensive studies were conducted. As a result, if an epoxy resin having a dicyclopentadiene skeleton having a bulky molecular structure is used as the curable component, it is surprisingly possible to suppress hydrolysis of the resin by water molecules and to improve B-HAST resistance and PCT resistance. The headline and the present invention were completed.

  That is, the curable resin composition of the present invention comprises (A) a carboxyl group-containing resin, (B) an epoxy resin having a dicyclopentadiene skeleton, (C) a photopolymerization initiator, (D) spherical silica, The (D) spherical silica is characterized in that the content thereof is 50% by mass or more in the nonvolatile component of the composition.

  In the curable resin composition of the present invention, the (B) epoxy resin having a dicyclopentadiene skeleton has an epoxy group ratio of 0.5 to 2 with respect to 1 mol of the carboxyl group in the (A) carboxyl group-containing resin. It is preferable to mix | blend so that it may become 0.5 mol.

  Moreover, the dry film of this invention has a resin layer obtained from the said curable resin composition, It is characterized by the above-mentioned.

  Furthermore, the cured product of the present invention is obtained by curing the curable resin composition or the resin layer of the dry film.

  Furthermore, the printed wiring board of the present invention is characterized by having the cured product.

  According to the curable resin composition of the present invention, it is possible to suppress the progress of hydrolysis such as ester bonds while preventing the water absorption of the cured product, and to prevent deterioration of insulation and adhesion. As a result, even when highly filled with an inorganic filler such as spherical silica in the curable resin composition, B-HAST resistance is ensured while ensuring excellent reliability as a cured product such as high rigidity and excellent TCT resistance. And a curable resin composition excellent in PCT resistance, a dry film using the same, a cured product, and a printed wiring board can be obtained.

Hereinafter, embodiments of the present invention will be described in detail.
(Curable resin composition)
The curable resin composition of the present invention includes (A) a carboxyl group-containing resin, (B) an epoxy resin having a dicyclopentadiene skeleton, (C) a photopolymerization initiator, and (D) spherical silica. (D) The spherical silica has a content of 50% by mass or more in the nonvolatile component of the composition.

  Thus, the composition containing the epoxy resin (B) having a dicyclopentadiene skeleton in the composition, the dicyclopentadiene skeleton having a bulky molecular structure blocks the free space in the crosslinked structure of the cured product, It is considered that water molecules can be prevented from penetrating into the resin and hydrolysis of the resin cured product by water molecules can be suppressed. As a result, even when highly filled with an inorganic filler such as spherical silica in the curable resin composition, excellent B- is achieved while ensuring excellent reliability as a cured product such as high rigidity and excellent TCT resistance. HAST resistance and PCT resistance can be maintained.

[(A) Carboxyl group-containing resin]
As the carboxyl group-containing resin, various conventionally known 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 bond is preferably derived from acrylic acid or methacrylic acid or a derivative thereof. In the case of using only a carboxyl group-containing resin having no ethylenically unsaturated double bond, in order to make the composition photocurable, a compound having a plurality of ethylenically unsaturated groups in the molecule described later, that is, light It is necessary to use a reactive monomer together.
Specific examples of the carboxyl group-containing resin include the following compounds (any of oligomers and polymers).

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

  (2) Diisocyanates such as aliphatic diisocyanates, branched aliphatic diisocyanates, alicyclic diisocyanates, aromatic diisocyanates, carboxyl group-containing dialcohol compounds such as dimethylolpropionic acid and dimethylolbutanoic acid, polycarbonate polyols, polyethers A carboxyl group-containing urethane resin by a polyaddition reaction of a diol compound such as a polyol, a polyester-based polyol, a polyolefin-based polyol, an acrylic polyol, a bisphenol A-based alkylene oxide adduct diol, a compound having a phenolic hydroxyl group and an alcoholic hydroxyl group.

  (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 obtained by a polyaddition reaction of (meth) acrylate or a partially acid anhydride-modified product thereof, a carboxyl group-containing dialcohol compound, and a diol compound.

  (4) During the synthesis of the resin of the above (2) or (3), a compound having one hydroxyl group and one or more (meth) acryloyl groups in a molecule such as hydroxyalkyl (meth) acrylate is added, and the terminal ( (Meth) acrylic 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 obtained by adding a compound having a terminal (meth) acrylate.

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

  (7) A carboxyl obtained by reacting (meth) acrylic acid with a polyfunctional epoxy resin obtained by 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) Two bases such as phthalic anhydride, tetrahydrophthalic anhydride, and hexahydrophthalic anhydride are reacted with a dicarboxylic acid such as adipic acid, phthalic acid, and hexahydrophthalic acid on a bifunctional oxetane resin. A carboxyl group-containing polyester resin to which an 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, and (meth) Reacting with an unsaturated group-containing monocarboxylic acid such as acrylic acid, and then reacting with the alcoholic hydroxyl group of the resulting reaction product, maleic anhydride, tetrahydrophthalic anhydride, trimellitic anhydride, pyromellitic anhydride, adipine A carboxyl group-containing resin obtained by reacting a polybasic acid anhydride such as an acid.

  (10) Reaction product obtained by reacting 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, with an unsaturated group-containing monocarboxylic acid. A carboxyl group-containing photosensitive resin obtained by reacting a product with a polybasic acid anhydride.

  (11) Obtained by reacting a compound having a plurality of phenolic hydroxyl groups in one molecule with a reaction product obtained by reacting a cyclic carbonate compound such as ethylene carbonate or propylene carbonate with an unsaturated group-containing monocarboxylic acid. 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 adding a compound having one epoxy group and one or more (meth) acryloyl groups in one molecule to the resins (1) to (11).
In addition, in this specification, (meth) acrylate is a term that collectively refers to acrylate, methacrylate, and mixtures thereof, and the same applies to other similar expressions.

  The acid value of the carboxyl group-containing resin is suitably in the range of 30 to 150 mgKOH / g, more preferably in the range of 50 to 120 mgKOH / g. When the acid value of the carboxyl group-containing resin is 30 mgKOH / g or more, alkali development is facilitated. On the other hand, when the acid value is 150 mgKOH / g or less, sufficient resistance to the developer in the exposed area is obtained, and a normal resist pattern Can be reliably drawn, which is preferable.

  Moreover, although the weight average molecular weight of the said carboxyl group containing resin changes with resin frame | skeletons, what is generally in the range of 2,000-150,000, Furthermore, 5,000-100,000 is preferable. 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 part is good and the resolution is excellent, and the storage stability may be improved. The weight average molecular weight can be measured by gel permeation chromatography.

  These carboxyl group-containing resins are not limited to those listed above, and one kind thereof may be used alone, or a plurality of kinds may be mixed and used. Among these, carboxyl group-containing resins synthesized using a phenol compound such as the carboxyl group-containing resins (10) and (11) as starting materials are excellent in B-HAST resistance and PCT resistance, and therefore can be suitably used.

[(B) Epoxy resin having dicyclopentadiene skeleton]
(B) As an epoxy resin having a dicyclopentadiene skeleton, for example, Epicron HP-7200 manufactured by DIC Corporation, Adeka Resin EP-4088L manufactured by ADEKA Corporation, and the like can be suitably used. (B) The epoxy resin which has a dicyclopentadiene frame | skeleton can be used individually by 1 type or in combination of 2 or more types.

  The epoxy resin having the (B) dicyclopentadiene skeleton has a ratio of epoxy group of 0.5 to 2.5 mol, more preferably 0.8 to 2 with respect to 1 mol of carboxyl group in the (A) carboxyl group-containing resin. It is preferable to mix | blend so that it may be set to 0.0 mol. (B) By making the compounding quantity of component 0.5 mol or more, the improvement effect of B-HAST tolerance of a hardened | cured material or PCT tolerance can be acquired favorably. Moreover, favorable developability is acquired by the compounding quantity of (B) component being 2.5 mol or less.

  In the curable resin composition, in addition to (B) the epoxy resin having a dicyclopentadiene skeleton, other epoxy resins may be further blended within a range not impairing the effects specific to the present invention. Examples of such other epoxy resins include epoxidized vegetable oils; bisphenol A type epoxy resins; hydroquinone type epoxy resins; bisphenol type epoxy resins; thioether type epoxy resins; brominated epoxy resins; novolac type epoxy resins; Epoxy resin; Bisphenol F type epoxy resin; Hydrogenated bisphenol A type epoxy resin; Glycidylamine type epoxy resin; Hydantoin type epoxy resin; Alicyclic epoxy resin; Trihydroxyphenylmethane type epoxy resin; Bixylenol type or biphenol type epoxy resin Or a mixture thereof; bisphenol S type epoxy resin; bisphenol A novolak type epoxy resin; tetraphenylolethane type epoxy resin; heterocyclic epoxy resin Diglycidyl phthalate resin; Tetraglycidyl xylenoyl ethane resin; Naphthalene group-containing epoxy resin; Glycidyl methacrylate copolymer epoxy resin; Copolymer epoxy resin of cyclohexylmaleimide and glycidyl methacrylate; Epoxy modified polybutadiene rubber derivative; CTBN modified epoxy Resins etc. are mentioned, but it is not limited to these. In the curable resin composition of the present invention, when (B) an epoxy resin having a dicyclopentadiene skeleton and another epoxy resin are used in combination, the total amount of the epoxy resin is converted into a non-volatile component and the component (B) It is preferable that 10 mass% or more of the epoxy resin having the above-mentioned dicyclopentadiene skeleton is included, more preferably 20 to 80 mass%.

[(C) Photopolymerization initiator]
(C) Any known photopolymerization initiator can be used. (B) A photoinitiator may be used individually by 1 type, and may be used in combination of 2 or more type.

  (C) Specific examples of the 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- (2,4,6-Trimethylbenzoyl) -phenylphos Bisacylphosphine oxides such as phosphine oxide; 2,6-dimethoxybenzoyldiphenylphosphine oxide, 2,6-dichlorobenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoylphenylphosphinic acid methyl ester, 2-methyl Monoacylphosphine oxides such as benzoyldiphenylphosphine oxide, pivaloylphenylphosphinic acid isopropyl ester, 2,4,6-trimethylbenzoyldiphenylphosphine oxide (IGNrad TPO manufactured by IGM); phenyl (2,4 6-trimethylbenzoyl) ethyl phosphinate, 1-hydroxy-cyclohexyl phenyl ketone, 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydro Ci-2-methyl-1-propan-1-one, 2-hydroxy-1- {4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] phenyl} -2-methyl-propane-1 -Hydroxyacetophenones such as 2-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one; benzoin, benzyl, benzoin methyl ether, benzoin ethyl ether, benzoin n-propyl ether, benzoin isopropyl ether, benzoin n- Benzoins such as butyl ether; benzoin alkyl ethers; benzophenones such as benzophenone, p-methylbenzophenone, Michler's ketone, methylbenzophenone, 4,4'-dichlorobenzophenone, 4,4'-bisdiethylaminobenzophenone; Non, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 1-hydroxycyclohexyl phenyl 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) Acetophenones such as methyl) -1- [4- (4-morpholinyl) phenyl] -1-butanone and N, N-dimethylaminoacetophenone; thioxanthone, 2-ethylthioxanthone, 2-isopropylthioxanthone, 2,4-dimethylthioxanthone 2,4-diethylthioxanthone, 2-chloro Thioxanthones such as thioxanthone and 2,4-diisopropylthioxanthone; anthraquinone, chloroanthraquinone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 1-chloroanthraquinone, 2-amylanthraquinone, 2-aminoanthraquinone, etc. Anthraquinones; ketals such as acetophenone dimethyl ketal and benzyl dimethyl ketal; benzoic acid esters such as ethyl-4-dimethylaminobenzoate, 2- (dimethylamino) ethylbenzoate and p-dimethylbenzoic acid ethyl ester; -Octanedione, 1- [4- (phenylthio)-, 2- (O-benzoyloxime)], ethanone, 1- [9-ethyl-6- (2-methylbenzoyl) -9H-cal Oxime esters such as zol-3-yl]-, 1- (O-acetyloxime); bis (η5-2,4-cyclopentadien-1-yl) -bis (2,6-difluoro-3- (1H) -Tyranocenes such as -pyrrol-1-yl) phenyl) titanium, bis (cyclopentadienyl) -bis [2,6-difluoro-3- (2- (1-pyr-1-yl) ethyl) phenyl] titanium And phenyl disulfide 2-nitrofluorene, butyroin, anisoin ethyl ether, azobisisobutyronitrile, tetramethylthiuram disulfide and the like.

  Among these, monoacylphosphine oxide photopolymerization initiators and bisacylphosphine oxide photopolymerization initiators are preferable because they have photobleaching properties. Here, photobleaching is also called photobleaching or photobleaching, and is a reaction that occurs because a fluorescent substance in an excited state is chemically activated and becomes unstable compared to the ground state. Specifically, when a compound acting as a photopolymerization initiator absorbs light in a specific wavelength region and generates radicals, the structure of the compound changes due to the generation of radicals, and light in that wavelength region changes. It means that it will not absorb. Thereby, since it becomes easy to let the light in the wavelength range pass, it becomes easy to photocure to a deep part. In particular, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (OMIRAD TPO manufactured by IGM), bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide (IRGACURE819 manufactured by BASF Japan Ltd.), phenyl ( 2,4,6-trimethylbenzoyl) ethyl phosphinate (IRGACURE TPO-L manufactured by BASF Japan Ltd.) and the like can be suitably used.

  It is preferable that the compounding quantity of the photoinitiator except an oxime ester system photoinitiator is 0.1-30 mass parts with respect to 100 mass parts of (A) carboxyl group-containing resin in conversion of a non-volatile component. When the amount is 0.1 parts by mass or more, the photocurability of the resin composition is good, the coating film is hardly peeled off, and the coating properties such as chemical resistance are also good. On the other hand, in the case of 30 parts by mass or less, an effect of reducing outgas is obtained, and light absorption on the surface of the solder resist coating film is good, and the deep curability is hardly lowered. More preferably, it is 0.5-15 mass parts. Moreover, it is preferable that the compounding quantity of an oxime ester system photoinitiator shall be 0.01-5 mass parts with respect to 100 mass parts of (A) carboxyl group-containing resin in conversion of a non-volatile component. When the amount is 0.01 parts by mass or more, the photocurability of the resin composition is good, and the coating film properties such as heat resistance and chemical resistance are also good. On the other hand, in the case of 5 parts by mass or less, the light absorption of the solder resist coating film is good, and the deep part curability is hardly lowered. More preferably, it is 0.5-3 mass parts.

[(D) Spherical silica]
As (D) spherical silica, any spherical silica can be used as long as it can be used as a filler for electronic materials, and one kind may be used alone, or two or more kinds may be used in combination. Moreover, the shape of (C) spherical silica should just be spherical shape, and is not limited to a true spherical thing. Suitable (C) spherical silica includes, for example, those having a sphericity measured as follows of 0.8 or more, but are not limited thereto.

The sphericity is measured as follows. That is, first, a photograph of spherical silica was taken with a scanning electron microscope (SEM), and from the area and circumference of the particles observed on the photograph, (sphericity) = {4π × (area) ÷ (ambient Long) Calculated as a value calculated in ² }. Specifically, an average value measured for 100 particles using an image processing apparatus can be employed.

  In the present invention, as (D) spherical silica, it is preferable to use spherical silica (D1) having an average particle diameter of 300 nm to 1000 nm, and more preferably, the average particle diameter is 500 nm to 900 nm.

  Here, in this specification, the average particle diameter of (D) spherical silica is not only the particle diameter of primary particles but also the average particle diameter (D50) including the particle diameter of secondary particles (aggregates). , D50 value measured by laser diffraction method. An example of a measuring apparatus using the laser diffraction method is Microtrac MT3300EXII manufactured by Nikkiso Co., Ltd. Note that the maximum particle size (D100) and the particle size (D10) can be measured in the same manner using the above-described apparatus.

  In the present invention, two types of spherical silica having different average particle diameters can be used as the (D) spherical silica. That is, in addition to spherical silica (D1) having an average particle diameter of 300 nm to 1000 nm, spherical silica (D2) having an average particle diameter of 1 nm or more and less than 300 nm can be used in combination. By using together, since the spherical silica (D2) is filled into the gaps between the spherical silica (D1), the gap amount can be reduced. Thereby, (D) spherical silica can be highly filled in the composition, and a curable resin composition having a low resin content, that is, a high ratio of filler mass in the total mass can be obtained.

  Even within the same normal commercial product, the particle size originally varies 2-3 times, but since the fine particles do not effectively enter the gap at that ratio, spherical silica (D1) and spherical silica ( It is preferable that there is a difference of 5 times or more in the average particle diameter with D2). The larger the average particle size ratio between the spherical silica (D1) and the spherical silica (D2), the better. The average particle diameter of the spherical silica (D1) is more preferably 8 times or more, and further preferably 10 times or more the average particle diameter of the spherical silica (D2).

  Moreover, it is preferable that the largest particle diameter (D100) of spherical silica (D1) is 5 micrometers or less. The maximum particle size varies depending on the use of the curable resin composition, and is preferably 5 μm or less for use in forming a cured film on a package substrate, for example. Furthermore, the particle diameter (D10) of the spherical silica (D1) is preferably 5 times or more the average particle diameter (D50) of the spherical silica (D2). When this ratio is 5 times or more, the filling efficiency of the spherical silica (D2) into the gaps of the spherical silica (D1) is improved, and the balance between the strength of the cured product and the laminate property of the dry film is excellent.

  In addition, it is preferable that the compounding ratio in the case of using spherical silica (D1) and spherical silica (D2) together is spherical silica (D1): spherical silica (D2) = 5: 5 to 9: 1 by volume ratio. 6: 4 to 8: 2 is more preferable. It is preferable for it to be within the above-mentioned range since both the strength of the cured product and the laminate property of the dry film can be further achieved.

  The method for producing spherical silica is not particularly limited, and methods known to those skilled in the art can be applied. For example, it can be manufactured by burning silicon powder by a VMC (Vaporized Metal Combustion) method. In the VMC method, a chemical flame is formed by a burner in an oxygen-containing atmosphere, and metal powder that constitutes part of the target oxide particles is introduced into the chemical flame in such an amount that a dust cloud is formed. In this method, deflagration is caused to obtain oxide particles.

  In addition, as spherical silica (D1) as commercially available spherical silica, for example, Admafine SO-C2 and SO-E2 manufactured by Admatechs Co., Ltd., SFP-20M and SFP- manufactured by Denka Co., Ltd. Examples of spherical silica (D2) include Admanano (manufactured by Admatechs), UFP-30 (Denka), Seahoster series (manufactured by Nippon Shokubai Co., Ltd.), Sakai Chemical Industry ( Examples include Sciqas series manufactured by Co., Ltd., SG-SO100 manufactured by Kyoritsu Material Co., Ltd., and the like.

  (D) The presence or absence of surface treatment of the spherical silica is not particularly limited, but the curable resin composition of the present invention is highly filled with (D) spherical silica and has a relatively low resin content. Silica is preferably subjected to a surface treatment for improving dispersibility. Aggregation can be suppressed by using a filler that has been surface-treated. In addition, when (D) spherical silica (D1) and spherical silica (D2) are used together as spherical silica, only one of them may be surface-treated, or both may be surface-treated.

  (D) The surface treatment method of the spherical silica is not particularly limited, and a known and commonly used method may be used. A surface treatment agent having a curable reactive group, for example, a coupling agent having a curable reactive group as an organic group, etc. It is preferable to treat the surface of the inorganic filler.

  As the coupling agent, coupling agents such as silane, titanate, aluminate and zircoaluminate can be used. Of these, 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 coupling agents are preferably immobilized in advance on the surface of spherical silica by adsorption or reaction. Here, it is preferable that the processing amount of the coupling agent with respect to 100 parts by mass of (D) spherical silica is 0.5 to 10 parts by mass. In the present invention, the reactive functional group derived from coupling (D) applied to the spherical silica is not included in the compound having a photocurable reactive group or a thermosetting functional group.

  Examples of the photocurable reactive group include ethylenically unsaturated groups such as a vinyl group, a styryl group, a methacryl group, and an acrylic group. Among these, at least one of a vinyl group and a (meth) acryl group is preferable.

  Examples of thermosetting reactive groups include hydroxyl groups, carboxyl groups, isocyanate groups, amino groups, imino groups, epoxy groups, oxetanyl groups, mercapto groups, methoxymethyl groups, methoxyethyl groups, ethoxymethyl groups, ethoxyethyl groups, oxazoline groups, etc. Is mentioned. Among these, at least one of an amino group and an epoxy group is preferable.

  In addition, the surface-treated (D) spherical silica may be contained in the curable resin composition of the present invention in a surface-treated state. The surface-untreated (D) spherical silica, the surface treatment agent, The (D) spherical silica may be surface-treated in the composition by separately blending, but it is preferable to blend the (D) spherical silica that has been surface-treated in advance. By blending the (D) spherical silica that has been surface-treated in advance, it is possible to suppress a decrease in crack resistance or the like due to the surface treatment agent that has not been consumed by the surface treatment that can remain when blended separately. When the surface treatment is performed in advance, it is preferable to blend a predispersion liquid in which (D) spherical silica is predispersed in a solvent or a curable component. More preferably, the liquid is mixed into the composition, or after sufficiently surface-treating when the surface-untreated (D) spherical silica is predispersed in the solvent, this predispersed liquid is blended into the composition.

  (D) The spherical silica may be blended with the component (A) or the like in a powder or solid state depending on how the curable resin composition of the present invention is used, and after mixing with a solvent or a dispersant to form a slurry. And may be blended with the component (A).

  (D) Content of spherical silica needs to be 50 mass% or more in the non-volatile component of a composition, Preferably it is 50 mass%-85 mass%, More preferably, 70 mass%-85 mass%, More preferably, it is more than 80 mass%-85 mass%. (D) By making content of spherical silica into 50 mass% or more in the non-volatile component of a composition, hardened | cured material can be made high intensity | strength and high rigidity, and a linear expansion coefficient (CTE) can be made low, and it is preferable.

[Photopolymerizable monomer]
A photopolymerizable monomer can be blended with the curable resin composition of the present invention. The photopolymerizable monomer is a compound having an ethylenically unsaturated double bond. Examples of such a photopolymerizable monomer include alkyl (meth) acrylates such as 2-ethylhexyl (meth) acrylate and cyclohexyl (meth) acrylate; 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) Hydroxyalkyl (meth) acrylates such as acrylates; Mono- or di (meth) acrylates of alkylene oxide derivatives such as ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol; hexanediol, trimethylolpropane, pentaerythritol, ditrimethylolpropane , Dipentaerythritol, trishydroxyethyl isocyanurate and other polyhydric alcohols or their addition of ethylene oxide or propylene oxide Polyhydric (meth) acrylates; Phenoxyethyl (meth) acrylate, (meth) acrylates of ethylene oxide or propylene oxide adducts of phenols such as polyethoxydi (meth) acrylate of bisphenol A; Glycerin diglycidyl ether, trimethylolpropane And (meth) acrylates of glycidyl ethers such as triglycidyl ether and triglycidyl isocyanurate; and melamine (meth) acrylates.

  A photopolymerizable monomer can be used individually by 1 type or in combination of 2 or more types. The content of the photopolymerizable monomer is preferably a ratio of 0.5 to 20 parts by mass with respect to 100 parts by mass of the (A) carboxyl group-containing resin in terms of nonvolatile components. When the blending amount is 0.5 parts by mass or more, the photocurability is good, and pattern formation is easy in alkali development after irradiation with active energy rays. On the other hand, in the case of 20 parts by mass or less, halation hardly occurs and good resolution can be obtained.

[Thermosetting catalyst]
A thermosetting catalyst can be mix | blended with the curable resin composition of this invention. Examples of the thermosetting catalyst include imidazole, 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 4-phenylimidazole, 1-cyanoethyl-2-phenylimidazole, 1- Imidazole derivatives such as (2-cyanoethyl) -2-ethyl-4-methylimidazole; dicyandiamide, benzyldimethylamine, 4- (dimethylamino) -N, N-dimethylbenzylamine, 4-methoxy-N, N-dimethylbenzyl Examples include amines, amine compounds such as 4-methyl-N, N-dimethylbenzylamine, hydrazine compounds such as adipic acid dihydrazide and sebacic acid dihydrazide; phosphorus compounds such as triphenylphosphine, and the like. 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 and isocyanuric acid adducts and 2,4-diamino-6-methacryloyloxyethyl-S-triazine and isocyanuric acid adducts can also be used. A compound that also functions in combination with a thermosetting catalyst.

  A thermosetting catalyst can be used individually by 1 type or in combination of 2 or more types. The compounding amount of the thermosetting catalyst is preferably 0.5 to 10 parts by mass and more preferably 1 to 8 parts by mass with respect to 100 parts by mass of the (A) carboxyl group-containing resin in terms of nonvolatile components. . In the case of 0.5 parts by mass or more, the heat resistance is excellent. In the case of 10 parts by mass or less, the storage stability is improved.

[Colorant]
The curable resin composition of the present invention may contain a colorant. As the colorant, conventionally known colorants such as red, blue, green, yellow, white, and black can be used, and any of pigments, dyes, and pigments may be used.

  Specific examples include color index (CI; issued by The Society of Dyer's and Colorists) number.

  Examples of the red colorant include monoazo series, diazo series, azo lake series, benzimidazolone series, perylene series, diketopyrrolopyrrole series, condensed azo series, anthraquinone series, and quinacridone series. As the blue colorant, there are phthalocyanine series, anthraquinone series, and the like, and as the pigment series, a compound classified as Pigment can be used. In addition to these, metal-substituted or unsubstituted phthalocyanine compounds can also be used. Similarly, the green colorant includes phthalocyanine, anthraquinone and perylene. In addition to these, metal-substituted or unsubstituted phthalocyanine compounds can also be used. Examples of the yellow colorant include monoazo, disazo, condensed azo, benzimidazolone, isoindolinone, and anthraquinone. Examples of the white colorant include rutile type or anatase type titanium oxide. Black colorants include carbon black, graphite, iron oxide, titanium black, anthraquinone, cobalt oxide, copper oxide, manganese, antimony oxide, nickel oxide, perylene, aniline, and sulfide. There are molybdenum and bismuth sulfide. In addition, a colorant such as purple, orange or brown may be added for the purpose of adjusting the color tone.

  From the viewpoint of improving the concealability of the cured product, the content of the colorant is preferably 0.18 to 0.50% by mass in terms of nonvolatile components per total amount of the curable resin composition. When it is 0.18% by mass or more in terms of nonvolatile components, the circuit concealing property is excellent, and when it is 0.50% by mass or less, the resolution is more excellent. More preferably, it is 0.20 mass%-0.40 mass%.

[Organic solvent]
The curable resin composition of the present invention can contain an organic solvent for the purpose of preparing the composition and adjusting the viscosity when applied to a substrate or a 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 , Glycol ethers such as 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, butylcarby Tall acetate, propylene glycol monomethyl ether acetate, dip Propylene glycol monomethyl ether acetate, esters such as propylene carbonate; octane, aliphatic hydrocarbons decane; petroleum ether, petroleum naphtha, and petroleum solvents such as solvent naphtha, organic solvents conventionally known can be used. These organic solvents can be used alone or in combination of two or more.

[Other additive components]
The curable resin composition of the present invention may further include a photoinitiator aid, a cyanate compound, an elastomer, a mercapto compound, a urethanization catalyst, a thixotropic agent, an adhesion promoter, a block copolymer, and a chain transfer agent as necessary. , Polymerization inhibitors, copper damage inhibitors, antioxidants, rust inhibitors, fine silica, organic bentonite, montmorillonite and other thickeners, silicone-based, fluorine-based, polymer-based antifoaming agents and / or leveling agents Ingredients such as flame retardants such as silane coupling agents such as imidazole, thiazole and triazole, phosphinic acid salts, phosphoric acid ester derivatives and phosphorus compounds such as phosphazene compounds 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-component or two-component or more.

  The curable resin composition of the present invention is useful for forming a pattern layer as a permanent film of a printed wiring board such as a solder resist, a cover lay, and an interlayer insulating layer, and is particularly useful for forming a solder resist. Moreover, since the curable resin composition of the present invention can form a cured product having excellent film strength even in a thin film, it is used in a printed wiring board that is required to be thin, such as a package substrate (printed wiring board used for a semiconductor package). It can also be suitably used for forming a pattern layer. Furthermore, the cured product obtained from the curable resin composition of the present invention is preferably used for forming a pattern layer on a package substrate having a thin total thickness and lacking rigidity even in terms of high elastic modulus and low CTE. It can be done.

[Dry film]
The curable resin composition of this invention can also be made into the form of the dry film provided with the support (carrier) film and the resin layer which consists of the said curable resin composition formed on this support film. When forming a dry film, the curable resin composition of the present invention is diluted with the above organic solvent to adjust to an appropriate viscosity, and is applied to a comma coater, blade coater, lip coater, rod coater, squeeze coater, reverse coater, transfer roll coater. A film can be obtained by applying a uniform thickness on a carrier film with a gravure coater, spray coater or the like, and drying usually at a temperature of 50 to 130 ° C. for 1 to 30 minutes. Although there is no restriction | limiting in particular about a coating film thickness, Generally, it is 1-150 micrometers in the film thickness after drying, Preferably it selects suitably in the range of 10-60 micrometers.

  A plastic film is used as the support film, and a plastic film such as a polyester film such as polyethylene terephthalate (PET), a polyimide film, a polyamideimide film, a polypropylene film, or a polystyrene film is preferably used. Although there is no restriction | limiting in particular about the thickness of a support film, Generally, it selects suitably in the range of 10-150 micrometers.

  After forming the resin layer of the curable resin composition of the present invention on the support film, the protective layer (cover) that can be peeled off from the surface of the resin layer for the purpose of preventing dust from adhering to the surface of the resin layer. ) It is preferable to laminate films. As the peelable protective film, for example, a polyethylene film, a polytetrafluoroethylene film, a polypropylene film, a surface-treated paper, etc. can be used, and when the protective film is peeled off, the adhesive force between the resin layer and the support film As long as the adhesive strength between the resin layer and the protective film is smaller.

  In the present invention, a resin layer may be formed by applying and drying the curable resin composition of the present invention on the protective film, and a support film may be laminated on the surface. That is, as a film to which the curable resin composition of the present invention is applied when producing a dry film in the present invention, either a support film or a protective film may be used.

[Cured product]
The cured product of the present invention is obtained by curing the curable resin composition of the present invention or the resin layer of the dry film of the present invention, and has high rigidity and thermal dimensional stability.

[Printed wiring board]
The printed wiring board of the present invention has a cured product obtained from the curable resin composition of the present invention or the resin layer of the dry film. As a method for producing a printed wiring board of the present invention, for example, the curable resin composition of the present invention is adjusted to a viscosity suitable for a coating method using the organic solvent, and a dip coating method is performed on a substrate. After coating by a method such as a flow coating method, a roll coating method, a bar coater method, a screen printing method, or a curtain coating method, 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 peeling the support film after laminating the substrate so that the resin layer is in contact with the substrate.

  Examples of the base material include printed wiring boards and flexible printed wiring boards that have been previously formed with copper or the like, paper phenol, paper epoxy, glass cloth epoxy, glass polyimide, glass cloth / non-woven cloth epoxy, glass cloth / paper epoxy. It is made of materials such as copper-clad laminates for high-frequency circuits using synthetic fiber epoxy, fluororesin, polyethylene, polyphenylene ether, polyphenylene oxide, cyanate, etc., and copper-clad laminates of all grades (FR-4 etc.) Examples thereof include a plate, a metal substrate, a polyimide film, a polyethylene terephthalate film, a polyethylene naphthalate (PEN) film, a glass substrate, a ceramic substrate, and a wafer plate.

  Volatile drying performed after the application of the curable resin composition of the present invention is performed in a dryer using a hot air circulation drying furnace, an IR furnace, a hot plate, a convection oven or the like (equipped with a heat source of an air heating method using steam). The method can be carried out using a method in which hot air is brought into countercurrent contact and a method in which the hot air is blown onto the support.

  After the resin layer is formed on the substrate, it is selectively exposed with active energy rays through a photomask having a predetermined pattern, and the unexposed portion is diluted with a dilute alkaline aqueous solution (for example, 0.3 to 3 mass% sodium carbonate aqueous solution). To develop a cured product pattern. Further, the cured product is irradiated with active energy rays and then heat-cured (for example, 100 to 220 ° C.), irradiated with active energy rays after heat-curing, or subjected to final finish curing (main-curing) only by heat-curing. A cured film having excellent properties such as properties and hardness is formed.

As an exposure machine used for the active energy ray irradiation, a high-pressure mercury lamp lamp, an ultra-high pressure mercury lamp lamp, a metal halide lamp, a mercury short arc lamp, and the like may be used as long as the apparatus irradiates ultraviolet rays in a range of 350 to 450 nm. Furthermore, a direct drawing apparatus (for example, a laser direct imaging apparatus that directly draws an image with a laser using 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 is generally 10 to 1000 mJ / cm ² , preferably 20 to 800 mJ / cm ² .

  The developing method can be a dipping method, a shower method, a spray method, a brush method, etc., and as a developing solution, potassium hydroxide, sodium hydroxide, sodium carbonate, potassium carbonate, sodium phosphate, sodium silicate, Alkaline aqueous solutions such as ammonia and amines can be used.

  The curable resin composition of the present invention may be used not only for the purpose of forming a pattern of a cured film with the developer as described above, but also for a purpose of not forming a pattern, such as a mold application (sealing application).

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further in detail, this invention is not restrict | limited by these Examples and a comparative example. In the following description, “parts” and “%” are all based on mass unless otherwise specified.

(Synthesis Example 1)
(Synthesis of carboxyl group-containing photosensitive resin A-1)
In an autoclave equipped with a thermometer, a nitrogen introduction device / alkylene oxide introduction device, and a stirring device, a novolac-type cresol resin (trade name “Shonol CRG951”, manufactured by Showa Denko KK, OH equivalent: 119.4) 119.4 Part by mass, 1.19 parts by mass of potassium hydroxide and 119.4 parts by mass of toluene were introduced, the system was purged with nitrogen while stirring, and the temperature was raised. Next, 63.8 parts by mass of propylene oxide was gradually added dropwise and reacted at 125 to 132 ° C. and 0 to 4.8 kg / cm ² for 16 hours. Thereafter, the mixture was cooled to room temperature, and 1.56 parts by mass of 89% phosphoric acid was added to and mixed with the reaction solution to neutralize potassium hydroxide. The nonvolatile content was 62.1% and the hydroxyl value was 182.2 mgKOH / g (307 0.9 g / eq.) Of a novolac-type cresol resin propylene oxide reaction solution. This was an average of 1.08 moles of propylene oxide added per equivalent of phenolic hydroxyl group.

  293.0 parts by mass of the resulting novolak-type cresol resin propylene oxide reaction solution, 43.2 parts by mass of acrylic acid, 11.53 parts by mass of methanesulfonic acid, 0.18 parts by mass of methylhydroquinone and 252.9 parts by mass of toluene Then, it was introduced into a reactor equipped with a stirrer, a thermometer and an air blowing tube, and air was blown at a rate of 10 ml / min, and the reaction was carried out at 110 ° C. for 12 hours while stirring. The water produced | generated by reaction distilled 12.6 mass parts water as an azeotrope with toluene. Then, it cooled to room temperature and neutralized the obtained reaction solution with 35.35 mass parts of 15% sodium hydroxide aqueous solution, and then washed with water. Thereafter, toluene was distilled off while substituting 118.1 parts by mass of diethylene glycol monoethyl ether acetate with an evaporator to obtain a novolak acrylate resin solution. Next, 332.5 parts by mass of the resulting novolak acrylate resin solution and 1.22 parts by mass of triphenylphosphine were introduced into a reactor equipped with a stirrer, a thermometer and an air blowing tube, and air was supplied at 10 ml / min. While stirring and stirring, 60.8 parts by mass of tetrahydrophthalic anhydride was gradually added, reacted at 95 to 101 ° C. for 6 hours, cooled, and taken out. In this way, a solution of a photosensitive carboxyl group-containing resin having a nonvolatile component of 70.6% by mass and a solid acid value of 87.7 mgKOH / g was obtained.

(Preparation Example 1)
(Preparation of surface-treated spherical silica B-1)
70 parts by mass of spherical silica (SFP-30M, Denka Corp., average particle size: 600 nm), 28 parts by mass of PMA (propylene glycol monomethyl ether acetate) as a solvent, and a silane coupling agent having a methacryl group (Shin-Etsu Chemical Co., Ltd.) 2 parts by mass of KBM-503 (3-methacryloxypropyltrimethoxysilane) produced were uniformly dispersed to obtain a silica solvent dispersion product having a nonvolatile component of 70% by mass.

(Preparation Example 2)
(Preparation of surface-treated spherical silica B-2)
70 parts by mass of spherical silica (SG-SO100 manufactured by Kyoritsu Material Co., Ltd., average particle diameter d50 = 100 nm), 28 parts by mass of PMA (propylene glycol monomethyl ether acetate) as a solvent, and a silane cup having a methacrylic group 2 parts by mass of a ring agent (KBM-503 (3-methacryloxypropyltrimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd.) was uniformly dispersed to obtain a silica solvent dispersion product having a nonvolatile component of 70% by mass.

<Preparation of curable resin composition>
In accordance with the formulation shown in Table 1 below, each component was blended, premixed with a stirrer, dispersed with a three-roll mill, and kneaded to prepare curable resin compositions. The compounding quantity in a table | surface shows a mass part. Using the obtained curable resin compositions of Examples and Comparative Examples, evaluation was performed as follows.

<Evaluation of CTE>
The curable resin composition of each Example and Comparative Example was applied over the entire surface of the copper foil substrate. This was dried and allowed to cool to room temperature to form a resin layer made of a curable resin composition. On the other hand, exposure was performed through a strip-shaped negative mask of 50 mm × 3 mm with an optimal exposure amount. Then, it developed by injecting 1 mass% sodium carbonate aqueous solution of 30 degreeC, and obtained the pattern of the cured film. Furthermore, it heated and hardened | cured on predetermined conditions, and obtained the evaluation board | substrate.

The cured film of the evaluation board | substrate obtained by the above was peeled off from copper foil, and evaluation was implemented. The measurement was performed using a TMA measuring apparatus (TMA / SS6000 manufactured by Shimadzu Corporation) to obtain CTEα1 (0-50 ° C.). Judgment criteria are as follows.
○ ... less than 30ppm
× ... 30ppm or more

<Evaluation of B-HAST resistance>
A cured film of the curable resin composition of each example and comparative example was formed on a BT substrate on which comb-type electrodes (line / space = 20 μm / 15 μm) were formed, and an evaluation substrate was produced. This evaluation board | substrate was put into the high temperature, high humidity tank of the atmosphere of 130 degreeC and humidity 85%, the voltage 5V was applied, and the HAST test in a tank was done. The elapsed time when the insulation resistance value in the tank was less than 10 ⁶ Ω was evaluated according to the following criteria.
: Over 400 hours
○: 200 to 400 hours
×: Less than 200 hours

<Evaluation of TCT resistance>
The curable resin compositions of the examples and comparative examples were applied over the entire surface of the package substrate. This was dried and allowed to cool to room temperature to form a resin layer made of a curable resin composition. On the other hand, direct imaging exposure was performed on the copper pad at an optimum exposure amount with an opening size of 80 μm of SRO (Solder Resist Opening). Then, it developed by injecting 1 mass% sodium carbonate aqueous solution of 30 degreeC, and obtained the pattern of the cured film. Further, it was cured by heating under predetermined conditions. Thereafter, Au plating treatment and solder bump formation were performed, and a Si chip was mounted to obtain an evaluation substrate.

The evaluation board | substrate obtained by the above was put into the thermal cycle machine with which a temperature cycle is performed between -65 degreeC and 150 degreeC, and TCT (Thermal Cycle Test) was performed. Then, the surface of the cured film at 600 cycles, 800 cycles, and 1000 cycles was observed. Judgment criteria are as follows.
A: No abnormality after 1000 cycles
○: No abnormality at 800 cycles, cracks occurred at 1000 cycles
Δ: No abnormality at 600 cycles, cracks occurred at 800 cycles
×: Crack generated in 600 cycles

<Evaluation of PCT resistance>
The curable resin compositions of the examples and comparative examples were applied over the entire surface of the package substrate. This was dried and allowed to cool to room temperature to form a resin layer made of a curable resin composition. On the other hand, direct imaging exposure was performed with an SRO of 80 μm on the copper pad with an optimal exposure amount. Then, it developed by injecting 1 mass% sodium carbonate aqueous solution of 30 degreeC, and obtained the pattern of the cured film. Furthermore, it heated and hardened | cured on predetermined conditions, and obtained the evaluation board | substrate.

About the obtained evaluation board | substrate, PCT (Pressure Cooker Test) was performed for 168 hours on the conditions of 121 degreeC, saturation, and 0.2MPa using the PCT apparatus (Espec Co., Ltd. HAST SYSTEM TPC-412MD). And the state of the coating film after PCT was evaluated. Judgment criteria are as follows.
○: No swelling, peeling, discoloration, or elution
×: Swelling, peeling, discoloration and elution are often observed

  These evaluation results are also shown in the following table.

* 1) Carboxyl group-containing photosensitive resin A-1 obtained in Synthesis Example 1
* 2) HP-7200 (dicyclopentadiene type epoxy resin, manufactured by DIC Corporation, epoxy equivalent 260 g / eq)
* 3) jER834 (bisphenol A type epoxy resin, manufactured by Mitsubishi Chemical Corporation, epoxy equivalent 250 g / eq)
* 4) N-730 (phenol novolac type epoxy resin, manufactured by DIC Corporation, epoxy equivalent 175 g / eq)
* 5) EOCN1020 (cresol novolac type epoxy resin, Nippon Kayaku Co., Ltd., epoxy equivalent 200 g / eq)
* 6) TPO (2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, Omnirad TPO, manufactured by IGM)
* 7) Surface-treated spherical silica B-1 obtained in Preparation Example 1 (methacrylic silane treatment, average particle diameter 600 nm, nonvolatile component 70% by mass)
* 8) Surface-treated spherical silica B-2 obtained in Preparation Example 2 (methacrylic silane treatment, average particle size 100 nm, nonvolatile component 70% by mass)
* 9) DPHA (dipentaerythritol hexaacrylate, manufactured by Nippon Kayaku Co., Ltd.)

As is clear from the evaluation results shown in the above table, in each example, the B-HAST resistance and the PCT resistance are improved while ensuring excellent reliability such as rigidity and TCT resistance when cured. It was confirmed that the obtained curable resin composition was obtained.

Claims (4)

(A) a carboxyl group-containing resin;
(B) an epoxy resin having a dicyclopentadiene skeleton;
(C) a photopolymerization initiator;
(D) spherical silica;
And a content of the spherical silica (D) is 50% by mass or more in the nonvolatile component of the composition.   A dry film comprising a resin layer obtained from the curable resin composition according to claim 1.   A cured product obtained by curing the curable resin composition according to claim 1 or the resin layer of the dry film according to claim 2. A printed wiring board comprising the cured product according to claim 3.