Laminated curable resin structure, dry film, cured product and electronic component

Abstract

To provide a laminated curable resin structure from which a cured product that has high resolution and crack resistance and excellent adhesion to metal plating can be obtained.SOLUTION: A laminated curable resin structure is composed of two resin layers in which an X layer composed of an alkali-soluble resin composition X and a Y layer composed of an alkali-soluble resin composition Y are laminated, wherein the X layer is 5% or more and 30% or less of the thickness of the total two resin layers combined with the Y layer, the alkali-soluble resin compositions of the X layer and the Y layer contain inorganic particles, the inorganic particles of the X layer are inorganic particles containing a metal element having O, S and N in a coordinated electron, and the inorganic particles of the Y layer contain silica.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a laminated curable resin structure, a dry film, a cured product, and an electronic component. [Background technology]

[0002] In recent years, rapid advances in semiconductor components have led to a trend toward lighter, thinner, smaller, higher performance, and more multi-functional electronic devices. Following this trend, proposals have been made for smaller, more multi-pin, and even higher-density semiconductor packages that combine chips with different performance capabilities in a single package.

[0003] Specifically, high-density IC packages such as FC-CSP (flip-chip chip-scale package), FC-BGA (flip-chip ball grid array), and FO-WLP (fan-out wafer-level package) have been put to practical use for smartphone AP (application processor) applications. In organic interposers, and in some cases glass or silicon interposers, used in such high-density IC packages, the conductive vias formed in the insulating layer made of curable resin are becoming smaller in diameter. Circuit wiring is also becoming finer and denser. Therefore, the insulating materials used in such interposers must have high insulation reliability and patterning ability (resolution). Furthermore, when high-density wiring is formed using the semi-additive method, excellent adhesion between the curable resin and the plated metal, specifically copper, is required. This is because when vias formed in an insulating layer made of the cured curable resin are filled with conductive copper by electroless copper plating using the semi-additive method, the adhesion between the curable resin and copper affects the reliability of the wiring.

[0004] Regarding high-resolution photosensitive resin compositions, in order to suppress warpage due to the difference in thermal expansion coefficient between a semiconductor chip and a substrate that accompanies thinner package substrates, there is a photosensitive resin composition for permanent mask resist in which inorganic filler is highly loaded, and the highly loaded inorganic filler contains two types with different average particle sizes, and also contains an organic filler (Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 6210060 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the technique described in Patent Document 1 does not necessarily provide sufficient adhesion to metal plating. To improve adhesion to metal plating, methods have been considered in which the cured curable resin is subjected to a dry plasma treatment or a wet desmear treatment as a pretreatment to roughen the surface and create an anchoring effect. However, when dry plasma treatment is performed for a long period of time on a curable resin containing a filler, as described in Patent Document 1, the filler contained in the resin is likely to become exposed to the surface. Because filler does not have good adhesion to metal plating, it is difficult to obtain sufficient adhesive strength if a large amount of filler is exposed to the surface. If the filler is surface-treated, even if the filler is exposed to the surface by plasma, the surface is modified, and adhesion to organic materials can be expected. However, when it comes to adhesion to metal plating, if the filler is coordinated to the surface, it is still difficult to obtain sufficient adhesion.

[0007] Another pretreatment method for improving adhesion has been investigated: surface roughening using a desmear solution. Compared to plasma treatment, using a desmear solution makes it more difficult for the filler in the curable resin to maintain its surface coordination state, and the contact interface with the metal plating is primarily resin, which is expected to result in high adhesive strength. However, if the surface of a curable resin composition is immersed in a desmear solution for a long period of time to create a sufficient anchor shape on the surface, the cured product is damaged by the desmear solution, resulting in a decrease in strength and, in fact, poor adhesion. In particular, when the curable resin is an alkali-soluble resin, it is difficult to form an ideal roughened surface on the surface due to its low resistance to the high pH of the desmear solution. In response to this, some conventional alkali-soluble resins have improved alkali resistance, but they have poor developability during patterning, poor productivity, and difficulty in achieving high resolution.

[0008] Accordingly, an object of the present invention is to provide a laminated curable resin structure that can give a cured product that has high resolution, crack resistance, and excellent adhesion to metal plating; a dry film having a resin layer obtained from the laminated curable resin structure; a cured product of the resin layer of the laminated curable resin structure or the dry film; and an electronic component having the cured product. [Means for solving the problem]

[0009] The present inventors have conducted extensive research to develop an alkali-soluble resin composition that has high resolution, crack resistance, and high adhesion to metal plating. As a result, they have discovered that by forming an alkali-soluble resin composition into a two-layer laminated curable resin structure in which one layer with improved adhesion to metal plating and one layer with improved physical properties in terms of reliability are laminated in the thickness direction, it is possible to achieve insulating reliability due to high crack resistance and high adhesion to metal plating while maintaining the high resolution of the alkali-soluble resin composition, thereby arriving at the present invention.

[0010] That is, the laminated curable resin structure of the present invention comprises: the resin film is composed of two resin layers, an X layer made of an alkali-soluble resin composition X and a Y layer made of an alkali-soluble resin composition Y, laminated together, and the X layer accounts for 5% to 30% of the total thickness of the two resin layers combined with the Y layer; The alkali-soluble resin compositions X and Y of the X layer and the Y layer contain inorganic particles, the inorganic particles of the X layer contain inorganic particles containing a metal element having O, S, or N in its coordination electrons, and the inorganic particles of the Y layer contain silica.

[0011] In the laminated curable resin structure of the present invention, it is preferable that the alkali-soluble resin compositions X and Y of the X layer and the Y layer further contain at least one selected from a radical polymerizable compound and an epoxy resin, Furthermore, it is preferable that the alkali-soluble resin compositions X and Y of the X layer and the Y layer contain at least one selected from rubber particles and elastomers having an average particle size of 100 nm or more and 1 μm or less, Furthermore, the alkali-soluble resin compositions X and Y of the X layer and the Y layer preferably contain a curing accelerator.

[0012] The dry film of the present invention is characterized by having a resin layer obtained by applying the laminated curable resin structure to a film and drying it. The cured product of the present invention is characterized by being obtained by curing the resin layer of the laminated curable resin structure or the dry film. The electronic component of the present invention is characterized by comprising the cured product. [Effects of the Invention]

[0013] According to the present invention, it is possible to provide a laminated curable structure having high resolution (shape sharpness), crack resistance (heat and cold resistance) and high adhesion to metal plating, a dry film having a resin layer obtained from the laminated curable structure, a cured product of the resin layer of the laminated curable structure or the dry film, and an electronic component having the cured product. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a schematic cross-sectional view of an example of the dry film of the present invention. [Figure 2] FIG. 2 is a sketch of an SEM photograph in which the resolution (shape sharpness) of Example 1 was evaluated. [Figure 3] FIG. 10 is a sketch of an SEM photograph in which the resolution (shape sharpness) of Comparative Example 2 was evaluated. DETAILED DESCRIPTION OF THE INVENTION

[0015] The laminated curable resin structure, dry film, cured product, and electronic part of the present invention will now be described in more detail. The laminated curable resin structure is composed of two resin layers, an X layer made of alkali-soluble resin composition X and a Y layer made of alkali-soluble resin composition Y, laminated together. This two-layer structure, laminated in the resin thickness direction, is formed on a substrate such as a printed wiring board or flexible printed wiring board on which a circuit made of copper or the like has been formed in advance, with the Y layer being the bottom side of a via formed in this structure and the X layer being the top side of the via. This two-layer laminated curable resin structure is a combination of X and Y layers with different properties, with the proportion of the X layer being a specific percentage or less of the total thickness of the X and Y layers, the alkali-soluble resin compositions X and Y of the X and Y layers containing inorganic particles, and the inorganic particles of the X layer being inorganic particles containing a metal element having O, S, or N in its coordination electrons, and the inorganic particles of the Y layer containing silica. This allows for a balance of high resolution, crack resistance, and high adhesion to metal plating. The laminated curable resin structure of the present invention may also be a structure comprising another layer on the outer side of the X layer or the Y layer of the laminate of the X layer and the Y layer.

[0016] The thickness of the X layer is 30% or less of the total thickness of the two resin layers, including the Y layer. By making the thickness 30% or less, the X layer can sufficiently ensure adhesion to the metal plating while ensuring the physical properties, particularly crack resistance, of the Y layer. There is no particular lower limit for the thickness of the X layer, but it is preferably 5% or more of the total thickness of the two resin layers, including the Y layer.

[0017] Furthermore, adhesion to metal plating can be achieved by using different resin compositions for the X layer and the Y layer. Regarding adhesion to metal plating, the X layer contains inorganic particles containing metal elements with O, S, or N in the coordination electrons as inorganic particles, thereby improving the adhesion of metal plating, and preferably also contains rubber particles or elastomer, which facilitates anchor formation, thereby making it possible to form a layer that improves the adhesion of metal plating when either plasma pretreatment or desmear pretreatment is performed. Furthermore, because the X layer contains few inorganic particles and is mostly a resin layer, there is little light scattering, which allows for good shape sharpness at the top of the via.

[0018] The Y layer emphasizes physical properties to ensure insulation reliability through high crack resistance throughout the laminated curable resin structure, and contains silica particles as inorganic particles, which allows the layer to have a good tapered shape at the bottom of the via.

[0019] Each component of the laminated curable resin structure will be described below. In this specification, the term "(meth)acrylate" is a general term that refers to acrylate, methacrylate, and mixtures thereof, and the same applies to other similar expressions.

[0020] [(A) Alkali-soluble resin] The alkali-soluble resin compositions X and Y of the X and Y layers both contain an alkali-soluble resin. The alkali-soluble resin is, for example, a resin containing one or more alkali-soluble groups selected from the group consisting of a phenolic hydroxyl group, a thiol group, and a carboxyl group. Preferred examples include compounds having two or more phenolic hydroxyl groups, carboxyl group-containing resins, compounds having a phenolic hydroxyl group and a carboxyl group, and compounds having two or more thiol groups. As the (A) alkali-soluble resin, a carboxyl group-containing resin or a phenolic hydroxyl group-containing resin can be used, but a carboxyl group-containing resin is preferred from the viewpoint of reactivity with the (B) epoxy resin.

[0021] In addition, a smaller weight-average molecular weight of the alkali-soluble resin (A) is preferable because it increases the proportion of alkali-soluble groups in the alkali-soluble resin and increases the crosslink density of the cured product. The weight-average molecular weight (Mw) of the alkali-soluble resin (A) is preferably 20,000 or less, calculated as polystyrene when measured by gel permeation chromatography (GPC).

[0022] From the viewpoints of developability, photocurability, and development resistance, the alkali-soluble resin (A) preferably has an ethylenically unsaturated group in addition to a carboxyl group in the molecule. Alternatively, a carboxyl group-containing resin without an ethylenically unsaturated group may be used. The ethylenically unsaturated group is preferably derived from acrylic acid, methacrylic acid, or a derivative thereof. Specific examples of the carboxyl group-containing resin include the compounds (which may be either oligomers or polymers) listed below.

[0023] (1) A carboxyl group-containing photosensitive resin obtained by reacting a difunctional or higher polyfunctional epoxy resin with (meth)acrylic acid and adding a dibasic acid anhydride such as phthalic anhydride, tetrahydrophthalic anhydride, or hexahydrophthalic anhydride to the hydroxyl groups present in the side chains. Here, the difunctional or higher polyfunctional epoxy resin is preferably solid.

[0024] (2) A carboxyl group-containing photosensitive resin obtained by reacting a polyfunctional epoxy resin in which the hydroxyl groups of a difunctional epoxy resin are further epoxidized with epichlorohydrin with (meth)acrylic acid, and then adding a dibasic acid anhydride to the resulting hydroxyl groups. Here, the difunctional epoxy resin is preferably solid.

[0025] (3) A carboxyl group-containing photosensitive resin obtained by reacting an epoxy resin having two or more epoxy groups per molecule with a compound having at least one alcoholic hydroxyl group and one phenolic hydroxyl group per molecule and an unsaturated group-containing monocarboxylic acid such as (meth)acrylic acid, and then reacting the alcoholic hydroxyl groups of the resulting reaction product with a polybasic acid anhydride such as maleic anhydride, tetrahydrophthalic anhydride, trimellitic anhydride, pyromellitic anhydride, or adipic anhydride.

[0026] (4) A carboxyl group-containing photosensitive resin obtained by reacting a compound having two or more phenolic hydroxyl groups in one molecule, such as bisphenol A, bisphenol F, bisphenol S, novolac-type phenolic resin, poly-p-hydroxystyrene, a condensation product of naphthol and aldehydes, or a condensation product of dihydroxynaphthalene and aldehydes, with an alkylene oxide, such as ethylene oxide or propylene oxide, and then reacting the resulting reaction product with an unsaturated group-containing monocarboxylic acid, such as (meth)acrylic acid, and then reacting the resulting reaction product with a polybasic acid anhydride.

[0027] (5) A carboxyl group-containing photosensitive resin obtained by reacting a compound having two or more phenolic hydroxyl groups per molecule with a cyclic carbonate compound such as ethylene carbonate or propylene carbonate, reacting the resulting reaction product with an unsaturated group-containing monocarboxylic acid, and then reacting the resulting reaction product with a polybasic acid anhydride.

[0028] (6) Carboxyl group-containing photosensitive resins obtained by copolymerizing unsaturated carboxylic acids such as (meth)acrylic acid with unsaturated group-containing compounds such as styrene, α-methylstyrene, lower alkyl (meth)acrylates, and isobutylene.

[0029] (7) Polyester resins containing carboxyl groups, which are obtained by reacting a polyfunctional oxetane resin with a dicarboxylic acid such as adipic acid, phthalic acid, or hexahydrophthalic acid, and then adding a dibasic acid anhydride to the resulting primary hydroxyl groups.

[0030] (8) A carboxyl group-containing photosensitive resin obtained by adding a compound having a cyclic ether group and a (meth)acryloyl group in one molecule to the carboxyl group-containing resin such as any of the above (1) to (7).

[0031] (9) A carboxyl group-containing photosensitive resin having a copolymer structure, which is obtained by adding a compound having one epoxy group and one or more (meth)acryloyl groups in the molecule, such as glycidyl (meth)acrylate, α-methylglycidyl (meth)acrylate, or epoxycyclohexylmethyl (meth)acrylate, to a carboxyl group-containing copolymer resin having as monomers maleimide or a maleimide derivative, such as N-phenylmaleimide or N-benzylmaleimide, an unsaturated carboxylic acid, such as (meth)acrylic acid, an unsaturated group-containing compound having a hydroxyl group, such as hydroxyalkyl (meth)acrylate, and an unsaturated group-containing compound having an aromatic ring, such as styrene, α-methylstyrene, α-chlorostyrene, or vinyltoluene.

[0032] Carboxyl group-containing resins having ethylenically unsaturated groups (also referred to as carboxyl group-containing photosensitive resins) preferably have a structure in which the ethylenically unsaturated groups in the side chains are spaced apart from the main chain derived from phenolic resins, epoxy resins, etc. In other words, when introducing ethylenically unsaturated groups into the side chains, it is preferable to introduce a chain extension structure so that a certain distance is created between the main chain and the ethylenically unsaturated groups. Such a structure is preferable because it improves the reactivity between the ethylenically unsaturated groups in the side chains. As carboxyl group-containing resins having a chain extension structure and ethylenically unsaturated groups, for example, the carboxyl group-containing resins described above in (3), (4), (5), and (8) are preferred.

[0033] The double bond equivalent of the (A) alkali-soluble resin and the laminated curable resin structure including the compound having an ethylenically unsaturated group, etc., described below, is 1000 g / eq or less. Being 1000 g / eq or less, coupled with the epoxy equivalent of the (B) epoxy resin, described below, being 1000 g / eq or less, improves the reactivity of the laminated curable resin structure, provides stable resistance to the electroless copper plating treatment solution, and ultimately enables the formation of an ideal roughened surface.

[0034] The acid value of the alkali-soluble resin is preferably 40 to 150 mgKOH / g. By making the acid value of the carboxyl group-containing resin 40 mgKOH / g or more, alkaline development becomes good. Furthermore, by making the acid value 150 mgKOH / g or less, it becomes easier to draw a normal cured product pattern. More preferably, it is 50 to 130 mgKOH / g.

[0035] The amount of the alkali-soluble resin (A) in the alkali-soluble resin compositions X and Y of the X and Y layers is, for example, 10 to 70 mass %, and preferably 20 to 60 mass %, based on the total solid content of the alkali-soluble resin compositions X and Y of the X and Y layers excluding the solvent. By making the amount 10 mass % or more, preferably 20 mass % or more, the coating strength can be improved. Furthermore, by making the amount 70 mass % or less, the processability can be improved. It is more preferably 30 to 50 mass %.

[0036] [(B) Epoxy resin] The alkali-soluble resin compositions X and Y of the X layer and the Y layer can both contain an epoxy resin, which is a thermosetting resin. By containing an epoxy resin, the crosslink density can be improved and the resistance to alkaline solutions such as electroless plating solutions can be further improved.

[0037] Epoxy resins include bisphenol A type epoxy resins, hydroquinone type epoxy resins, bisphenol type epoxy resins, thioether type epoxy resins, brominated epoxy resins, novolac type epoxy resins, biphenol novolac type epoxy resins, bisphenol F type epoxy resins, hydrogenated bisphenol A type epoxy resins, glycidylamine type epoxy resins, hydantoin type epoxy resins, alicyclic epoxy resins, trihydroxyphenylmethane type epoxy resins, alkylphenol type epoxy resins (e.g., bixylenol type epoxy resins), biphenol type epoxy resins, and bisphenol S type. Examples of epoxy resins include bisphenol A novolac epoxy resins, tetraphenylolethane epoxy resins, heterocyclic epoxy resins, diglycidyl phthalate resins, tetraglycidylxylenoylethane resins, naphthalene group-containing epoxy resins, epoxy resins having a dicyclopentadiene skeleton, triphenylmethane epoxy resins, epoxy resins having a silsesquioxane skeleton, glycidyl methacrylate copolymer epoxy resins, cyclohexylmaleimide and glycidyl methacrylate copolymer epoxy resins, epoxy-modified polybutadiene rubber derivatives, and CTBN-modified epoxy resins. The epoxy resins may be used alone or in combination of two or more. Among these, at least one of novolac epoxy resins, bisphenol epoxy resins, bixylenol epoxy resins, biphenol epoxy resins, biphenol novolac epoxy resins, naphthalene epoxy resins, epoxy resins having a silsesquioxane skeleton, and triphenylmethane epoxy resins is particularly preferred.

[0038] Alternatively, an epoxy resin having the structure of the following formula (I) containing trisphenolmethane and bisphenol A in the skeleton can be used. TIFF0007825341000001.tif38160

[0039] Epoxy resins having the structure of formula (I) above are aromatic polyfunctional epoxies with a high softening point, and therefore have excellent toughness and heat resistance. They are available, for example, as Techmore (registered trademark) VG3101L manufactured by Mitsui Chemicals, Inc. and NC-6300H manufactured by Nippon Kayaku Co., Ltd. Techmore VG3101L has a softening point of 60°C, a pale yellow solid with a Gardner color scale of 3 or less, an epoxy equivalent of 210 g / eq., and a total chlorine content of 1000 ppm or less, and possesses properties such as high heat resistance, low water absorption, and low cure shrinkage. The epoxy resin preferably contains two or more types of multifunctional epoxy resins from the viewpoint of increasing the crosslink density and lowering the CTE. In this specification, "multifunctional" means bifunctional or more functional.

[0040] The epoxy resin used in the alkali-soluble resin composition Y of the Y layer preferably contains a tri- or higher functional epoxy resin in order to improve adhesion to the substrate. The structure of the tri- or higher functional epoxy resin is not particularly limited, and it may be an epoxy resin having three or more epoxy groups.

[0041] Specific examples of commercially available epoxy resins with three or more functional epoxy groups include a trifunctional aminophenol type epoxy resin with the trade name "jER-630" (manufactured by Mitsubishi Chemical Corporation), a trifunctional triazine skeleton-containing epoxy resin with the trade names "TEPIC-S", "TEPIC-HP", and "TEPIC-VL" (manufactured by Nissan Chemical Industries, Ltd.), a trifunctional aromatic epoxy resin with the trade name "TECMO VG3101" (manufactured by Printec Co., Ltd.), a tetrafunctional aromatic epoxy resin with the trade name "GTR-1800" (manufactured by Nippon Kayaku Co., Ltd.), and a modified novolak epoxy resin with the trade name "GTR-1800" (manufactured by Nippon Kayaku Co., Ltd.). Examples of suitable epoxy resins include a cresol novolac type epoxy resin under the trade name "EPICLON-N740" (manufactured by DIC Corporation), a dicyclopentadiene type epoxy resin under the trade name "EPICLON-HP7200H-75M" (manufactured by DIC Corporation), a cresol novolac type epoxy resin under the trade name "EPICLON-N660" (manufactured by DIC Corporation), a phenol novolac type epoxy resin under the trade name "jER-152" (manufactured by Mitsubishi Chemical Corporation), and a naphthalene type epoxy resin under the trade name "ESN-175S" (manufactured by Nippon Steel Chemical & Material Co., Ltd.).

[0042] The amount of (B) epoxy resin in each of the alkali-soluble resin compositions X and Y for the X and Y layers is, for example, 1 to 100 parts by mass, preferably 10 to 80 parts by mass, and more preferably 20 to 60 parts by mass, per 100 parts by mass of the (A) alkali-soluble resin in each of the alkali-soluble resin compositions X and Y for the X and Y layers. When the amount of (B) thermosetting component is 1 part by mass or more, adhesion and mechanical properties are improved, and when it is 100 parts by mass or less, storage stability is improved. Note that, when rubber particles are blended in a form dispersed in an epoxy resin, as in the examples described below, the amount of epoxy resin in which the rubber particles are dispersed is also included in the amount of the epoxy resin.

[0043] The laminated curable resin structure containing the above-mentioned (B) epoxy resin has an epoxy equivalent of 1000 g / eq or less. The epoxy equivalent of 1000 g / eq or less, coupled with the double bond equivalent of 1000 g / eq or less of the laminated curable resin structure containing the above-mentioned (A) alkali-soluble resin, provides stable resistance to metal plating solutions and also enables the formation of an ideal roughened surface.

[0044] [Radical polymerizable compounds] The alkali-soluble resin compositions X and Y of the X and Y layers may each contain a radically polymerizable compound instead of or in addition to the epoxy resin of the present invention. Similar to the epoxy resin described above, the radically polymerizable compound can improve the crosslink density and further enhance resistance to alkaline solutions such as electroless plating solutions. Such radically polymerizable compounds include radically polymerizable resins and radically polymerizable monomers.

[0045] Examples of radically polymerizable resins that can be used include unsaturated polyesters, epoxy acrylates, urethane acrylates, polyester acrylates, polyether (meth)acrylates, and polybutadiene-modified (meth)acrylates. When using these radically polymerizable resins, it is preferable to use 80 parts by mass or less of the radically polymerizable resin per 100 parts by mass of the carboxyl group-containing photosensitive resin (A) in the alkali-soluble resin compositions X and Y of the X and Y layers. A more preferred upper limit is 70 parts by mass, and an even more preferred upper limit is 60 parts by mass.

[0046] The radical polymerizable monomer may be either a monofunctional monomer (having one radical polymerizable double bond) or a polyfunctional monomer (having two or more radical polymerizable double bonds). Because the radical polymerizable monomer participates in polymerization, it not only improves the properties of the resulting cured product but also adjusts the viscosity of the resin composition. When using a radical polymerizable monomer, the amount used is preferably 300 parts by mass or less, more preferably 100 parts by mass or less, per 100 parts by mass of the (A) carboxyl group-containing photosensitive resin in the alkali-soluble resin compositions X and Y of the X and Y layers. The preferred lower limit is 1 part by mass, more preferably 5 parts by mass, per 100 parts by mass of the (A) carboxyl group-containing photosensitive resin. When the (A) carboxyl group-containing photosensitive resin is used in combination with a carboxyl group-containing resin other than (A), the amount of the radical polymerizable monomer used is within the above range per 100 parts by mass of the combined amount of the (A) carboxyl group-containing photosensitive resin and the carboxyl group-containing resin other than (A).

[0047] Specific examples of radical polymerizable monomers include N-phenylmaleimide, N-(2-methylphenyl)maleimide, N-(4-methylphenyl)maleimide, N-(2,6-diethylphenyl)maleimide, N-(2-chlorophenyl)maleimide, N-methylmaleimide, N-ethylmaleimide, N-isopropylmaleimide, N-laurylmaleimide, N-cyclohexylmaleimide, N-phenylmethylmaleimide, N-(2,4,6-tribromophenyl)maleimide, N-[3-(triethoxysilyl)propyl]maleimide, N-octadecenylmaleimide, N-dodecenylmaleimide, N-(2-methyl ...methylmaleimide, N-methylmaleimide, N-methylmaleimide, N-methylmaleimide, N-methylmaleimide, N-methylmaleimide, N-methylmaleimide, N-methylmaleimide, N-methylmaleimide, N-methylmaleimide, N-methylmaleimide, N-methylmaleimide, N-methylmaleimide, N-methylmaleimide, N-methylmaleimide N-substituted maleimide group-containing monomers such as N-(2,4,6-trichlorophenyl)maleimide, N-(4-hydroxyphenyl)maleimide, and N-(1-hydroxyphenyl)maleimide; styrene derivatives such as styrene, α-methylstyrene, and α-chlorostyrene; aromatic vinyl monomers such as vinyltoluene, p-hydroxystyrene, divinylbenzene, diallyl phthalate, and diallyl benzene phosphonate; allyl compounds such as triallyl isocyanurate and diallyl isophthalate; vinyl ester monomers such as vinyl acetate, vinyl adipate, vinyl butyrate, and vinyl benzoate;(Meth)acrylic acid, methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, methoxyethyl (meth)acrylate, ethoxyethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 4-hydroxymethyl (meth)acrylamide, pentaerythritol mono(meth)acrylate, pentaerythritol Ethritol tri(meth)acrylate, dipentaerythritol mono(meth)acrylate, trimethylolpropane mono(meth)acrylate, butanediol di(meth)acrylate, 1,6-hexanediol mono(meth)acrylate, glycerol mono(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, (di)ethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, Propylene glycol di(meth)acrylate, trimethylolpropane di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane tri(meth)acrylate, tris[2-(meth)acryloyloxyethyl]triazine, dendritic acrylate, hydroxypivalate (Meth)acrylic monomers such as neopentyl glycol phosphate ester di(meth)acrylate; (meth)acrylic acid esters such as 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, isobornyl (meth)acrylate, phenyl (meth)acrylate, and phenoxyethyl (meth)acrylate; isocyanurate-type poly(meth)acrylates such as tris[(meth)acryloxyethyl]isocyanurate;(Meth)acrylamides such as acrylamide, methacrylamide, N-hydroxymethylacrylamide, N-hydroxymethylmethacrylamide, N-methoxymethylacrylamide, N-ethoxymethylacrylamide, and N-butoxymethylacrylamide; n-propyl vinyl ether, isopropyl vinyl ether, vinyl-n-butyl ether, vinyl-t-butyl ether, vinyl-n-amyl ether, vinyl isoamyl ether, vinyl-n-octadecyl ether, isobutyl vinyl ether, n-hexyl vinyl ether, cyclohexyl vinyl ether, 2-ethylhexyl vinyl ether, 4-hydroxybutyl vinyl ether, ethylene glycol monobutyl vinyl ether, and triethylene glycol monomethyl vinyl ether. vinyl (thio)ethers having a radically polymerizable double bond such as 2-(vinyloxyethoxy)ethyl (meth)acrylate, 2-(isopropenoxyethoxyethoxy)ethyl (meth)acrylate, 2-(isopropenoxyethoxyethoxy)ethyl (meth)acrylate, and 2-(isopropenoxyethoxyethoxyethoxy)ethyl (meth)acrylate; acid anhydride group-containing monomers such as maleic anhydride, or monomers obtained by ring-opening modification of the acid anhydride group with alcohols, amines, water, or the like; N-vinyl monomers such as N-vinylpyrrolidone and N-vinyloxazolidone; and compounds having one or more radically polymerizable double bonds such as allyl alcohol and triallyl cyanurate; These may be selected appropriately depending on the application and required properties, and may be used alone or in combination of two or more.

[0048] [(C) Inorganic particles] The alkali-soluble resin compositions X and Y of the X and Y layers both contain inorganic particles as inorganic fillers. The inclusion of inorganic particles reduces the thermal expansion coefficient and improves the alkali resistance of the cured product. The X layer contains inorganic particles containing metal elements with O, S, or N in the coordinated electrons. The inclusion of an inorganic component containing a metal element with O, S, or N in the coordinated electrons improves the adhesion of metal plating and provides excellent adhesion to the via wall surface. Specific examples of inorganic components containing a metal element with O, S, or N in the coordinated electrons include Al2O3, AlN, BaSO4, BaCO3, CaCO3, Ca(OH)2, MgO, Mg(OH)2, and Mg3SiO. 10 Examples include (OH)2, hydrotalcite, and hydrotalcite-like compounds. The average particle size of the inorganic component particles containing such specific metal elements is not particularly limited, but is preferably in the range of 1 nm to 2 μm from the viewpoint of appropriately mixing with spherical silica in the curable resin.

[0049] The hydrotalcite and hydrotalcite-like compounds are a type of naturally occurring clay mineral, and are, for example, composed of a positively charged base layer [Mg 1-X Al X (OH)2] X+ and a negatively charged intermediate layer [(CO3) X / 2 mH2O] X- It is a layered inorganic compound consisting of many divalent and trivalent metals, and its general structural formula is shown below in formula (II). TIFF0007825341000002.tif14155, M 2+ is Mg 2+ ,Fe 2+ ,Zn 2+ ,Ca 2+ ,Li 2+ ,Ni 2+ ,Co 2+ ,Cu 2+ Divalent metal cations such as M 3+ Al 3+ ,Fe 3+ ,Mn 3+ trivalent metal cations such as A n- is CO3 2-represents, and the subscript of each element and atomic group represents the ratio of each element and atomic group. X satisfies 0 < X ≤ 0.33, and m ≥ 0. Although m ≥ 0, it changes significantly due to dehydration.

[0050] Specific examples of the above-layered double hydroxide (A) include Indigirite Mg2Al2[(CO3)4(OH)2]·15H2O, Fe 2+ 4Al2[(OH) 12 CO3]·3H2O, Quintinite Mg4Al2(OH) 12 CO3·H2O, Manasseite Mg6Al2[(OH) 16 CO3]·4H2O, SjOegrenite Mg6Fe 3+ 2[(OH) 16 CO3]·4H2O, Zaccagnaite Zn4Al2(CO3)(OH) 12 ·3H2O, Desautelsite Mg6Mn 3+ 2[(OH) 16 CO3]·4H2O, Hydrotalcite Mg6Al2[(OH) 16 CO3]·4H2O, Pyroaurite Mg6Fe 3+ 2[(OH) 16 CO3]·4H2O, Reevesite Ni6Fe 3+ 2[(OH) 16 CO3]·4H2O, Stichtite Mg6Cr2[(OH) 16 CO3]·4H2O, Takovite Ni6Al2[(OH) 16 CO3]·4H2O and the like can be mentioned, and they can be used alone or in combination of two or more.

[0051] Also, as commercially available products of synthetic hydrotalcites, there are those manufactured by Kyowa Chemical Industry Co., Ltd.; Alkamazier, DHT-4A, Kyoward 500, Kyoward 1000, and those of the STABIACE series such as HT-1, HT-7, HT-P manufactured by Sakai Chemical Industry Co., Ltd. Particularly preferred are synthetic hydrotalcites, with an average particle size of 2 μm or less, and more preferably 1 μm or less. These hydrotalcites can be used as hydrates or in an anhydrous state after calcination.

[0052] The inorganic particle containing a metal element having O, S, or N in the coordinated electrons is preferably contained in the X layer in an amount of less than 20 mass % relative to the total solid content of the alkali-soluble resin composition X of the X layer. By containing it in an amount of less than 20 mass %, the adhesion of the metal plating to the via wall surface can be improved. The lower limit of the content is not particularly limited, but is more preferably 3 to 15 mass %.

[0053] The Y layer contains silica as inorganic particles. The silica is preferably slurried, and the average particle size after slurriing is preferably 1 to 900 nm. The silica in the Y layer more preferably has an average particle size of 700 nm or less. In this specification, the average particle size of the inorganic particles is the cumulative 50% volume particle size (D50 vol%), which includes not only the particle size of primary particles but also the particle size of secondary particles (aggregates). The average particle size can be determined using a laser diffraction particle size distribution analyzer and a measuring device using dynamic light scattering. An example of a measuring device using laser diffraction is Microtrac MT3300EXII manufactured by Microtrac-Bell, and an example of a measuring device using dynamic light scattering is Nanotrac Wave II UT151 manufactured by Microtrac-Bell. Among silicas, spherical silica is a preferred inorganic particle because it has a relatively small surface area compared to other types of silica, and stress is dispersed throughout the silica, making it less likely to become a starting point for cracks, and it also has excellent filling properties.

[0054] The Y layer preferably contains silica in an amount of 25% by mass or more and less than 50% by mass relative to the total solid content of the alkali-soluble resin composition Y of the Y layer. By including silica in an amount of 25% by mass or more and less than 50% by mass, it is possible to lower the CTE while imparting a tapered shape to the via bottom, and to improve plating adhesion and crack resistance of the cured product.

[0055] The spherical silica inorganic particles and the inorganic component containing the specific metal component are preferably surface-treated. The surface treatment is preferably a surface treatment with a coupling agent. As the coupling agent, a silane coupling agent, a titanium coupling agent, a zirconium coupling agent, an aluminum coupling agent, etc. can be used. Among them, a silane coupling agent is preferred. For the inorganic particles containing the specific metal element, a surface treatment of the inorganic particles can be used, which is expected to improve compatibility with the organic component.

[0056] Silane coupling agent is preferably a silane coupling agent that can introduce reactive groups into inorganic particles. Examples of silane coupling agents that can introduce reactive groups into inorganic particles include silane coupling agents having vinyl groups, silane coupling agents having methacryl groups, silane coupling agents having acrylic groups, silane coupling agents having epoxy groups, and silane coupling agents having carboxyl groups, and among them, silane coupling agents having at least one of (meth)acrylic groups and vinyl groups are preferred.

[0057] The surface-treated inorganic particles may be blended into the laminated curable resin structure in a surface-treated state. While untreated inorganic particles and a surface treatment agent may be blended separately to surface-treat the inorganic particles in the composition, blending pre-surface-treated inorganic particles is preferred. Blending pre-surface-treated inorganic particles can prevent degradation of crack resistance, etc., due to the surface treatment agent that may remain unconsumed during the surface treatment if blended separately. When surface-treating the inorganic particles in advance, it is preferred to blend a pre-dispersion in which the inorganic particles are pre-dispersed in a solvent or resin component. It is more preferred to pre-disperse the surface-treated inorganic particles in a solvent and then blend the pre-dispersion into the composition, or to thoroughly surface-treat the untreated inorganic particles when pre-dispersing them in a solvent, and then blend the pre-dispersion into the composition.

[0058] [(D) At least one selected from rubber particles and thermoplastic elastomers] The alkali-soluble resin compositions X and Y of the X layer and the Y layer of the present invention each preferably contain, as an organic filler, a material that contains a flexible polymer and serves as a stress relaxation agent for impact resistance, etc., such as at least one selected from rubber particles and thermoplastic elastomers.

[0059] (rubber particles) Specific examples of rubber particles include silicone rubber particles, acrylic rubber particles, cross-linked acrylonitrile butadiene rubber particles, cross-linked styrene butadiene rubber particles, and core-shell rubber particles, from the viewpoint of crack resistance, adhesion, electrical insulation, etc. of the cured film, with core-shell rubber particles being particularly preferred. Core-shell rubber particles refer to a rubber material with a multilayer structure consisting of core layers of different compositions and one or more shell layers covering the core layers. As described below, by forming the core layer of the core-shell rubber particles from a material with excellent flexibility and the shell layer from a material with excellent affinity for other components, it is possible to achieve a low modulus of elasticity by blending the rubber components while improving dispersibility.

[0060] The core layer is made of a material with excellent flexibility, such as a silicone elastomer, a butadiene elastomer, a styrene elastomer, an acrylic elastomer, a polyolefin elastomer, or a silicone / acrylic composite elastomer, but preferably a (meth)acrylate polymer.

[0061] Specific examples of the (meth)acrylate polymer constituting the core layer include: Ethyl acrylate and methyl methacrylate polymer, Methyl acrylate and methyl methacrylate polymers, Polymer of 2-ethylhexyl acrylate and methyl methacrylate, Polymers of butyl acrylate, butyl methacrylate and methyl methacrylate, Polymer of 2-ethylhexyl acrylate, methyl acrylate and methyl methacrylate, Butyl methacrylate, methyl acrylate and methyl methacrylate polymers, Polymer of butyl acrylate, ethyl acrylate and methyl methacrylate, -Butyl acrylate and methyl methacrylate polymer, -Butyl methacrylate and 2-ethylhexyl acrylate polymer, Isobutyl acrylate and methyl methacrylate polymer, Polymers of ethyl acrylate, methyl acrylate and methyl methacrylate, Polymer of butyl acrylate, 2-ethylhexyl acrylate and methyl methacrylate, Polymer of butyl methacrylate, ethyl acrylate and methyl methacrylate, -Butyl acrylate and isobutyl methacrylate polymer, Polymer of butyl acrylate, ethyl methacrylate and methyl acrylate, Polymers of butyl acrylate, methyl acrylate and methyl methacrylate, Ethyl acrylate and ethyl methacrylate polymers, Isobutyl acrylate and octadecyl methacrylate polymer, Polymer of butyl acrylate, isobutyl methacrylate and methyl methacrylate, -Butyl acrylate, methyl acrylate and octadecyl methacrylate polymer, Polymers of ethyl acrylate, ethyl methacrylate and methyl acrylate, Polymers of butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate and methyl methacrylate, Polymer of ethyl acrylate, isooctyl acrylate and methyl methacrylate, Butyl acrylate and dodecyl methacrylate polymer, Polymers of butyl acrylate, butyl methacrylate and 2-ethylhexyl acrylate, Polymer of 2-ethylhexyl acrylate, methyl methacrylate and octadecyl methacrylate, Polymer of butyl acrylate, methyl methacrylate and octadecyl methacrylate, Polymer of dodecyl methacrylate, 2-ethylhexyl acrylate and tridecyl methacrylate, Polymer of 2-ethylhexyl acrylate, methyl methacrylate, pentadecyl methacrylate and tetradecyl methacrylate, Polymers of butyl acrylate, butyl methacrylate, tert-butyl methacrylate and methyl methacrylate, Polymers of dodecyl methacrylate, ethyl acrylate, methyl methacrylate and tridecyl methacrylate are included. The core layer is preferably made of at least one of the above (meth)acrylate polymers.

[0062] On the other hand, a material having excellent affinity for other components is used as a constituent material of the shell layer. For example, when the alkali-soluble resin composition contains an epoxy resin, it is preferable to use core-shell rubber particles having a shell layer made of a material having excellent affinity for the epoxy resin.

[0063] The material constituting the core layer is preferably a rubbery polymer with a glass transition temperature of -30°C or lower, while the material constituting the shell layer is preferably a glassy polymer with a glass transition temperature of 70°C or higher. Such core-shell rubber particles can be produced by a multistage seed emulsion polymerization method consisting of at least two consecutive stages. Alternatively, the seed latex prepared in the first stage can be partially coagulated by solvent coagulation or the like, and then graft-polymerized onto the coagulated latex to form the shell.

[0064] In the first stage polymerization, a (meth)acrylate monomer having an alkyl group with 2 to 8 carbon atoms, preferably the (meth)acrylate monomer and a crosslinkable monomer, are polymerized to prepare a rubbery seed polymer having a glass transition temperature of −30° C. or lower.

[0065] The crosslinkable monomer may be one having two or more double bonds with substantially equal reactivity, such as ethylene glycol diacrylate, ethylene glycol dimethacrylate, butylene glycol diacrylate, butylene glycol dimethacrylate, trimethylolpropane diacrylate, trimethylolpropane dimethacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, hexanediol diacrylate, hexanediol methacrylate, oligoethylene diacrylate, oligoethylene dimethacrylate, aromatic divinyl monomers such as divinylbenzene, triallyl trimellitate, triallyl isocyanurate, etc. These crosslinkable monomers may be used alone or in combination of two or more, and the amount used is generally selected from the range of 0.01 to 5% by weight, preferably 0.1 to 2% by weight, based on the total weight of the monomers.

[0066] Furthermore, other copolymerizable monomers can be used as desired together with the (meth)acrylate monomer and crosslinkable monomer. Examples of such copolymerizable monomers include aromatic vinyl compounds such as styrene, vinyltoluene, and α-methylstyrene, vinyl cyanide compounds such as acrylonitrile and methacrylonitrile, and vinylidene cyanide, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 3-hydroxybutyl acrylate, 2-hydroxyethyl fumarate, hydroxybutyl vinyl ether, monobutyl maleate, glycidyl methacrylate, and butoxyethyl methacrylate. These monomers can be used alone or in combination of two or more, and the amount used is usually selected from a range of 50% by weight or less based on the total weight of the monomers.

[0067] Next, the thus obtained (meth)acrylate polymer particles are used as a core, and a second-stage emulsion polymerization is carried out to form a shell by graft copolymerization of a (meth)acrylate monomer having an alkyl group with 1 to 4 carbon atoms and a crosslinkable monomer. In this case, examples of the (meth)acrylate monomer having an alkyl group with 1 to 4 carbon atoms used include ethyl acrylate, n-butyl acrylate, methyl methacrylate, and butyl methacrylate. These may be used alone or in combination of two or more, but among these, methyl methacrylate is particularly preferred.

[0068] The crosslinkable monomer may be one or more selected from those exemplified in the description of the (meth)acrylate polymer forming the core. The amount of the crosslinkable monomer used is selected from the range of usually 0.01 to 10% by weight, preferably 0.1 to 5% by weight, based on the total weight of the monomers. Furthermore, other copolymerizable monomers can be used together with the (meth)acrylate monomer and crosslinkable monomer as desired. As such other copolymerizable monomers, one or more can be selected from those exemplified in the description of the (meth)acrylate polymer forming the core. The amount used is usually selected from the range of 50% by weight or less based on the total weight of the monomers.

[0069] The core-shell rubber particles obtained by such multistage emulsion polymerization are usually directly spray-dried to obtain core-shell type rubber particles that are excellent in dispersibility in resin components such as epoxy resins. These core-shell rubber particles can be obtained by at least two stages of multistage seed emulsion polymerization as described above, but in some cases they may be prepared by partially agglomerating the seed latex prepared in the first stage and then graft-polymerizing the seed latex thereon. Furthermore, after emulsion polymerization, the latex particles can be coagulated and separated by salting out or freezing, and the wet cake prepared by dehydration can be dried in a fluidized bed or the like to obtain agglomerated particles.

[0070] In the core-shell type rubber particles thus obtained, the content of the constituent material of the core layer is preferably in the range of 20 to 80% by weight, and the content of the constituent material of the shell layer is preferably in the range of 80 to 20% by weight.

[0071] Furthermore, the weight-average particle diameter of the core of the core-shell type powder polymer is preferably in the range of 0.1 to 2.0 μm. The core particles may be polymerized with the shell component following polymerization of the core component, or the core particles may be aggregated by solvent coagulation or salting-out coagulation before polymerization for coating with the shell component. Many known methods for secondary aggregation are available, and any of them can be used. Core particle diameters less than 0.1 μm result in poor dispersibility due to a large surface area per weight, significantly reducing the mechanical strength and storage stability of compositions containing the core-shell type powder polymer. Core particle diameters greater than 2.0 μm tend to result in reduced shear strength and peel strength. The average shell thickness of the core-shell type powder polymer is preferably 50 Å or greater. If the thickness is less than 50 Å, the shell component will not provide sufficient coverage, resulting in reduced storage stability. The content of the core-shell type rubber particles is preferably 10 to 100 parts by weight, more preferably 10 to 50 parts by weight, per 100 parts by weight of the alkali-soluble resin in each of the X layer and the Y layer.

[0072] The core-shell rubber particles may have curable reactive groups on their surfaces, which may be thermosetting reactive groups or photocurable reactive groups, or may have two or more types of curable reactive groups.

[0073] Examples of the thermosetting reactive group include a hydroxyl group, a carboxyl group, an isocyanate group, an imino group, an epoxy group, an oxetanyl group, a mercapto group, a methoxymethyl group, a methoxyethyl group, an ethoxymethyl group, an ethoxyethyl group, and an oxazoline group. An epoxy group is more preferable. Examples of the photocurable reactive group include an ethylenically unsaturated group such as a vinyl group, a styryl group, a methacrylic group, and an acrylic group.

[0074] The method for introducing the curable reactive groups on the surface of the rubber particles is not particularly limited, and they may be introduced by any known or commonly used method. For example, when forming a shell layer around the core layer, the shell layer can be introduced by polymerizing a material having a curable reactive group different from the functional group for polymerizing with the core layer into the core layer as a constituent material of the shell layer.

[0075] The rubber particles preferably have an average particle size of 1 nm to 2 μm in both the X layer and the Y layer, since this does not interfere with crosslinking, and more preferably 0.05 to 1 μm.

[0076] In the X layer and the Y layer, the content of rubber particles is preferably 0.01 to 20% by mass relative to the total solid content of the alkali-soluble resin compositions X and Y of each layer. A content of 0.01% by mass or more is preferable in that it provides an excellent roughening effect by pre-plating, forms dense irregularities different from inorganic fillers, forms a desirable anchor shape, and provides excellent adhesion of metal plating. On the other hand, a content of 20% by mass or less is preferable because it does not interfere with the crosslink density of the resin. A content of 0.01 to 15% by mass is more preferable. The alkali-soluble resin compositions X and Y may also contain rubber particles without curable reactive groups, as long as the effects of the invention are not impaired.

[0077] The total amount of rubber particles and elastomer in the alkali-soluble resin composition X of the X layer is greater than the total amount of rubber particles and elastomer in the alkali-soluble resin composition Y of the Y layer. By having a larger amount of rubber particles and elastomer in the X layer than in the Y layer, anchors are more easily formed on the surface of the X layer, which can improve the adhesion of metal plating when either plasma pretreatment or desmear pretreatment is performed.

[0078] (thermoplastic elastomer) The alkali-soluble resin compositions X and Y of the X and Y layers may each contain a thermoplastic elastomer as an organic filler in place of or in combination with the rubber particles. Known elastomers can be used as the thermoplastic elastomer. Examples of thermoplastic elastomers that can be used include polyester elastomers, polyurethane elastomers, polyesterurethane elastomers, polyamide elastomers, polyesteramide elastomers, acrylic elastomers, and olefin elastomers. Resins in which some or all of the epoxy groups of epoxy resins having various skeletons have been modified with both-end carboxylic acid-modified butadiene-acrylonitrile rubber can also be used. Furthermore, epoxy-containing polybutadiene elastomers, acrylic-containing polybutadiene elastomers, hydroxyl-containing polybutadiene elastomers, hydroxyl-containing isoprene elastomers, and block copolymers can also be used. For example, trade names include R-45HT, Poly bd HTP-9 (both manufactured by Idemitsu Kosan Co., Ltd.), Epolead PB3600 (manufactured by Daicel Corporation), Denalex R-45EPT (manufactured by Nagase ChemteX Corporation), Tafthren (manufactured by Sumitomo Chemical Co., Ltd.), Ricon 130, Ricon 131, Ricon 134, Ricon 142, Ricon 150, Ricon 152, Ricon 153, Ricon 154, Ricon 156, Ricon 157, Ricon 100, Ricon 181, Ricon 184, Ricon 130MA8, Ricon 130MA13, Ricon 130MA20, Ricon 131MA5, Ricon 131MA10, Ricon 131MA17, Ricon 131MA20, Ricon 184MA6, Ricon 156MA17 (all manufactured by Cray Valley Corp.), etc. These elastomers can be used alone or in combination of two or more.

[0079] (polyester polyol) The polyester elastomer according to the present invention may be, for example, a polyester polyol obtained by polycondensation of a polycarboxylic acid and a polyhydric alcohol. The polyester polyol contained in the X layer and the Y layer may be one type or multiple types.

[0080] (Polycarboxylic Acid) Examples of polycarboxylic acids include malonic acid, succinic acid, succinic anhydride, glutaric acid, adipic acid, azelaic acid, sebacic acid, phthalic acid, phthalic anhydride, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, isophthalic acid, terephthalic acid, nadic anhydride, maleic acid, maleic anhydride, fumaric acid, itaconic acid, citraconic acid, trimellitic acid, trimellitic anhydride, pyromellitic acid, and pyromellitic anhydride, and among these, aliphatic polycarboxylic acids such as succinic acid, adipic acid, and sebacic acid are preferably used.

[0081] (Polyhydric alcohol) Examples of polyhydric alcohols include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,3-butylene glycol, 1,4-butylene glycol, 1,2-butylene glycol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, diethylene glycol, dipropylene glycol, 2,2,4-trimethyl-1,3-pentanediol, cyclohexanediol, bisphenol A ethylene oxide adduct, bisphenol A propylene oxide adduct, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, glycerin, trimethylolpropane, trimethylolethane, and pentaerythritol, of which 1,2-propylene glycol, 1,4-butylene glycol, and 1,6-hexanediol are preferably used.

[0082] In particular, the polyester polyol used as the modifier according to the present invention is preferably an aliphatic polyester polyol, which is a polycondensate of an aliphatic polycarboxylic acid and an aliphatic polyhydric alcohol, because it can provide a fiber-reinforced composite material with high mechanical properties. In particular, an aliphatic polyester polyol using succinic acid, adipic acid, sebacic acid, or the like as the aliphatic polycarboxylic acid and 1,2-propylene glycol, 1,4-butylene glycol, 1,6-hexanediol, or the like as the aliphatic polyhydric alcohol is more preferred, because it can provide a fiber-reinforced composite material with high 90° flexural strength.

[0083] The weight average molecular weight of the polyester polyol is preferably 40,000 or less, more preferably 20,000 or less, and even more preferably 10,000 or less, from the viewpoint of developability. For example, trade names include Polylite OD-X-2068 and OD-X-3100 (both polyester polyols manufactured by DIC Corporation).

[0084] The elastomer may be used alone or in combination of two or more. The amount of the elastomer is preferably 0.01 to 20% by mass based on the total solid content of the alkali-soluble resin compositions X and Y of the X and Y layers.

[0085] [(E) Photopolymerization initiator] The alkali-soluble resin compositions X and Y of the X layer and the Y layer can both contain a photopolymerization initiator. By containing a photopolymerization initiator, radical polymerization by light becomes possible. In particular, a negative curable resin composition can be obtained. As the photopolymerization initiator, any photopolymerization initiator known as a photopolymerization initiator or a photoradical generator can be used.

[0086] Examples of the photopolymerization initiator include bis-(2,6-dichlorobenzoyl)phenylphosphine oxide, bis-(2,6-dichlorobenzoyl)-2,5-dimethylphenylphosphine oxide, bis-(2,6-dichlorobenzoyl)-4-propylphenylphosphine oxide, bis-(2,6-dichlorobenzoyl)-1-naphthylphosphine oxide, bis-(2,6-dimethoxybenzoyl)phenylphosphine oxide, bis-(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, bis-(2,6-dimethoxybenzoyl)-2,5-dimethylphenylphosphine oxide, and bis-(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (Omnirad, manufactured by IGM Resins). 819) and other bisacylphosphine oxides; monoacylphosphine oxides such as 2,6-dimethoxybenzoyldiphenylphosphine oxide, 2,6-dichlorobenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoylphenylphosphinic acid methyl ester, 2-methylbenzoyldiphenylphosphine oxide, pivaloylphenylphosphinic acid isopropyl ester, and 2,4,6-trimethylbenzoyldiphenylphosphine oxide; 1-hydroxy-cyclohexyl phenyl ketone, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy- Hydroxyacetophenones such as 1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-propan-1-one and 2-hydroxy-2-methyl-1-phenylpropan-1-one; benzoins such as benzoin, benzil, benzoin methyl ether, benzoin ethyl ether, benzoin n-propyl ether, benzoin isopropyl ether, and 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-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)methyl]-1-[ acetophenones such as 4-(4-morpholinyl)phenyl]-1-butanone and N,N-dimethylaminoacetophenone; thioxanthones such as thioxanthone, 2-ethylthioxanthone, 2-isopropylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, and 2,4-diisopropylthioxanthone; anthraquinone, chloroanthraquinone, 2-methylanthraquinone, 2-ethylanthraquinone, 2 Anthraquinones such as 1-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; 1,2-octanedione, 1-[4-(phenylthio)-, 2-(O-benzoyl)o]benzoates, etc. oxime)], ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, 1-(O-acetyloxime), and other oxime esters; bis(η5-2,4-cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrol-1-yl)phenyl)titanium, bis(cyclopentadienyl)-bis[2,6-difluoro-3-(2-(1-pyr-1-yl)ethyl)phenyl]titanium, and other titanocenes;Examples of suitable photopolymerization initiators include phenyl disulfide, 2-nitrofluorene, butyroin, anisoin ethyl ether, azobisisobutyronitrile, and tetramethylthiuram disulfide. One photopolymerization initiator may be used alone, or two or more may be used in combination. Among these, monoacylphosphine oxides and oxime esters are preferred, with highly sensitive oxime esters being most preferred. Oxime esters preferably have one or more oxime ester groups, and examples thereof include ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, and 1-(O-acetyloxime).

[0087] The blending amount of (E) photopolymerization initiator is preferably 0.5 to 30 parts by mass per 100 parts by mass of (A) alkali-soluble resin in each of the alkali-soluble resin compositions X and Y of the X and Y layers. When the blending amount is 0.5 parts by mass or more, good surface curing properties are obtained, and when the blending amount is 30 parts by mass or less, halation is unlikely to occur and good resolution is obtained.

[0088] (curing accelerator) When the alkali-soluble resin compositions X and Y for the X and Y layers each contain an epoxy resin as the thermosetting resin, they preferably further contain a curing accelerator. This allows the curing reaction of the epoxy resin to proceed effectively, enabling the X and Y layers to be cured satisfactorily. Examples of the curing accelerator include imidazole-based curing catalysts, amine-based curing catalysts, and phosphorus-based curing catalysts. Specific examples of imidazole-based curing accelerators include imidazole, 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-ethyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-phenylimidazole, 1,2-dimethylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-phenylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, and 2-phenyl-4,5-di(hydroxymethyl)imidazole. From the viewpoint of reactivity, it is preferable to use 2-ethyl-4-methylimidazole. Specific examples of amine-based curing accelerators include melamine, dicyandiamide, triazine compounds such as 2,4-diamino-6-[2'-methylimidazolyl-(1')]ethyl-s-triazine, and tertiary amine compounds such as 1,8-diazabicyclo[5,4,0]undecene-7 (DBU), triethylenediamine, benzyldimethylamine, and triethanolamine. Of these, 2,4-diamino-6-[2'-methylimidazolyl-(1')]ethyl-s-triazine is preferred. Specific examples of phosphorus-based curing catalysts include triphenylphosphine, tributylphosphine, tri(p-methylphenyl)phosphine, tri(nonylphenyl)phosphine, etc. Among these curing accelerators, amine-based curing accelerators are preferred because they also contribute to adhesion with surrounding materials.

[0089] The amount of the curing accelerator to be added is preferably 0.05 to 20 parts by mass, more preferably 0.1 to 15 parts by mass, per 100 parts by mass of the epoxy resin (B) in the alkali-soluble resin compositions X and Y of the X and Y layers.

[0090] (hardening agent) The alkali-soluble resin compositions X and Y of the X and Y layers may each contain a curing agent. Examples of the curing agent include phenolic resins, polycarboxylic acids and their acid anhydrides, cyanate ester resins, active ester resins, maleimide compounds, and alicyclic olefin polymers. The curing agents may be used alone or in combination of two or more.

[0091] (coloring agent) The alkali-soluble resin compositions X and Y of the X and Y layers may each contain a colorant. Known colorants such as red, blue, green, yellow, black, and white can be used as the colorant, and any of pigments, dyes, and coloring matters can be used. However, from the viewpoint of reducing environmental impact and adverse effects on the human body, it is preferable that the colorant does not contain halogen.

[0092] The amount of colorant added is not particularly limited, but is preferably 10 parts by mass or less, and particularly preferably 0.1 to 10 parts by mass, per 100 parts by mass of the alkali-soluble resin (A) in the alkali-soluble resin compositions X and Y of the X and Y layers.

[0093] (organic solvent) The alkali-soluble resin compositions X and Y of the X layer and Y layer may contain an organic solvent for the purpose of adjusting the viscosity when preparing the composition or when applying it to the substrate or the first film. Examples of the organic solvent include ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene, xylene, and tetramethylbenzene; glycol ethers such as cellosolve, methyl cellosolve, butyl cellosolve, carbitol, methyl carbitol, butyl carbitol, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol diethyl ether, diethylene glycol monomethyl ether acetate, and tripropylene glycol monomethyl ether; esters such as ethyl acetate, butyl acetate, butyl lactate, cellosolve acetate, butyl cellosolve acetate, carbitol acetate, butyl carbitol acetate, propylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether acetate, and propylene carbonate; aliphatic hydrocarbons such as octane and decane; and petroleum-based solvents such as petroleum ether, petroleum naphtha, and solvent naphtha. These organic solvents may be used alone or in combination of two or more.

[0094] (Other optional ingredients) Furthermore, the alkali-soluble resin compositions X and Y of the X layer and the Y layer may each contain other additives known and commonly used in the field of electronic materials, such as thermal polymerization inhibitors, ultraviolet absorbers, silane coupling agents, plasticizers, flame retardants, antistatic agents, antioxidants, antibacterial and antifungal agents, antifoaming agents, leveling agents, thickeners, adhesion-imparting agents, thixotropy-imparting agents, photoinitiator assistants, sensitizers, thermoplastic resins, core organic fillers, release agents, surface treatment agents, dispersants, dispersion assistants, surface modifiers, stabilizers, phosphors, and AB or ABA block copolymers.

[0095] [Dry film] The laminated curable resin structure of the present invention may be used in the form of a dry film or in liquid form. When used in liquid form, it may be one-component or two or more-component.

[0096] Next, the dry film of the present invention has a resin layer obtained by applying the laminated curable resin structure or alkali-soluble resin composition X or Y of the present invention onto a first film and drying it. Fig. 1 shows a schematic cross-sectional view of an example of a dry film 1. The dry film 1 in Fig. 1 has a laminated curable resin structure 11 in which an X layer 11X and a Y layer 11Y are laminated together, and a first film 12 is provided to cover the surface of the X layer 11X of the laminated curable resin structure 11, and a second film 13 is provided to cover the surface of the Y layer 11Y of the laminated curable resin structure 11.

[0097] To form a dry film, the alkali-soluble resin composition X for the X layer of the laminated curable resin structure of the present invention is first diluted with the organic solvent to an appropriate viscosity and then coated onto the first film in a uniform thickness using a comma coater, blade coater, lip coater, rod coater, squeeze coater, reverse coater, transfer roll coater, gravure coater, spray coater, or the like. The coated composition is then dried, typically at a temperature of 40 to 130°C for 1 to 30 minutes, to form the X layer. Next, the alkali-soluble resin composition Y for the Y layer is coated onto the X layer in a uniform thickness in the same manner as for the X layer, and dried to form the Y layer overlying the X layer, thereby obtaining the laminated curable resin structure of the present invention. The thickness of the entire coated film 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 the film thickness after drying.

[0098] The first film is 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. There are no particular restrictions on the thickness of the first film, but it is generally selected appropriately in the range of 10 to 150 μm, and more preferably in the range of 15 to 130 μm.

[0099] After forming a resin layer made of the laminated curable resin structure of the present invention on a first film, it is preferable to further laminate a peelable second film on the surface of the resin layer for the purpose of preventing dust from adhering to the surface of the resin layer. Examples of the peelable second film that can be used include polyethylene film, polytetrafluoroethylene film, polypropylene film, and surface-treated paper. The second film may be any film as long as the adhesive strength between the resin layer and the first film is smaller than that between the first film and the second film when peeled off.

[0100] In the present invention, the laminated curable resin structure of the present invention may be applied to the second film and dried to form a resin layer, and the first film may be laminated on the surface of the resin layer. That is, in the production of a dry film in the present invention, either the first film or the second film may be used as the film to which the laminated curable resin structure of the present invention is applied.

[0101] [Electronic Components] The electronic component of the present invention, such as a printed wiring board, comprises a cured product obtained from the resin layer of the laminated curable resin structure or dry film of the present invention. A method for producing a printed wiring board of the present invention involves, for example, adjusting the viscosity of the alkali-soluble resin composition Y of the Y layer of the laminated curable resin structure of the present invention to a level suitable for the coating method using the organic solvent described above, applying it to a substrate by a method such as dip coating, flow coating, roll coating, bar coating, screen printing, or curtain coating, and then evaporating and drying (pre-drying) the organic solvent contained in the composition at a temperature of 60 to 100°C for 1 to 30 minutes to form a tack-free resin layer of the Y layer. Next, the alkali-soluble resin composition X of the X layer is applied to the Y layer to a uniform thickness in the same manner as for the Y layer, and dried to form a resin layer X overlying the Y layer, thereby obtaining the laminated curable resin structure of the present invention. Alternatively, in the case of a dry film, the resin layer is attached to the substrate using a laminator or the like so that the resin layer contacts the substrate, and then peeling off the first film to form a resin layer on the substrate.

[0102] The substrates include printed wiring boards and flexible printed wiring boards with circuits already formed using copper or the like, as well as copper-clad laminates for high-frequency circuits made from materials such as paper phenol, paper epoxy, glass cloth epoxy, glass polyimide, glass cloth / non-woven cloth epoxy, glass cloth / paper epoxy, synthetic fiber epoxy, fluororesin, polyethylene, polyphenylene ether, polyphenylene oxide, cyanate, etc., including copper-clad laminates of all grades (FR-4, etc.), as well as metal substrates, polyimide film, PET film, polyethylene naphthalate (PEN) film, glass substrates, ceramic substrates, wafer plates, etc.

[0103] The volatilization drying carried out after application of the alkali-soluble resin compositions X and Y can be carried out using a hot air circulation drying oven, an IR oven, a hot plate, a convection oven, or the like (a method in which hot air in a dryer equipped with a heat source of an air heating method using steam is brought into countercurrent contact with the substrate, or a method in which hot air is blown onto the substrate from a nozzle).

[0104] After forming a resin layer on a printed wiring board, the resin layer is selectively exposed to active energy rays through a photomask with a predetermined pattern, and the unexposed areas are developed with a dilute alkaline aqueous solution (e.g., a 0.3 to 3% by mass aqueous solution of sodium carbonate) to form a pattern of a cured product. The cured product is then irradiated with active energy rays and then heat-cured (e.g., at 100 to 220°C for 20 to 120 minutes), or is heat-cured and then irradiated with active energy rays, or is heat-cured alone to form a final finish curing (main curing) to form a cured film with excellent properties such as adhesion and hardness.

[0105] The exposure device used for the above-mentioned active energy ray irradiation may be a device equipped with a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a metal halide lamp, a mercury short arc lamp, or the like, and capable of irradiating ultraviolet rays in the range of 350 to 450 nm. Furthermore, a direct imaging device (for example, a laser direct imaging device that directly draws an image with a laser based on CAD data from a computer) may also be used. The lamp or laser light source of the direct imaging device may have a maximum wavelength in the range of 350 to 450 nm. The exposure dose for image formation varies depending on factors such as the film thickness, but is generally 10 to 1,000 mJ / cm. 2 , preferably 20 to 800 mJ / cm 2 The range may be:

[0106] The developing method may be a dipping method, a shower method, a spray method, a brush method, or the like, and the developing solution may be an aqueous alkali solution such as potassium hydroxide, sodium hydroxide, sodium carbonate, potassium carbonate, sodium phosphate, sodium silicate, ammonia, or an amine.

[0107] The laminated curable resin structure of the present invention is suitable for use in forming a cured film on a printed wiring board, more preferably for forming a permanent coating, and even more preferably for forming a solder resist, an interlayer insulating layer, or a coverlay. It is also suitable for forming permanent coatings (especially solder resist) for high-density wiring on printed wiring boards having fine-pitch wiring patterns that require high reliability, such as package substrates, particularly for FC-CSP, FC-BGA, and FO-WLP applications. In particular, the laminated curable resin structure of the present invention can provide a cured product that exhibits excellent crack resistance under high-temperature loads, making it suitable for applications exposed to high temperatures, such as in-vehicle applications. [Example]

[0108] 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, "parts" and "%" are all by mass unless otherwise specified.

[0109] [Synthesis of alkali-soluble resin A-1] To 400 parts of phenol novolac epoxy resin EPPN-201 (manufactured by Nippon Kayaku, epoxy equivalent 187), 117 parts of ethylene glycol salicylate, 56 parts of acrylic acid, 67 parts of methacrylic acid, 274 parts of ethyl carbitol acetate, 3 parts of triphenylphosphine, and 0.5 parts of methyl hydroquinone were added and reacted at 110°C for 12 hours to obtain an ethyl carbitol acetate solution. To 400 parts of this solution, 64 parts of tetrahydrophthalic anhydride was added and reacted at 100°C for 5 hours. An alkali-soluble resin (A-1) containing 74% carboxyl group-containing curable resin with an acid value of 80 mgKOH / g was obtained.

[0110] [Synthesis of alkali-soluble resin A-2] 130 parts of biphenyl-type epoxy resin "YX4000" (manufactured by Mitsubishi Chemical Corporation), 43.3 parts of bisphenol S, 182.7 parts of propylene glycol monomethyl ether acetate, and 0.4 parts of benzyl triethyl ammonium chloride as a reaction catalyst were added and reacted at 140 ° C for 6 hours. After confirming the completion of the reaction between the phenolic hydroxyl group and the epoxy group by epoxy group quantification, 176.3 parts of bisphenol A-type epoxy resin (trade name "jER834"; manufactured by Japan Epoxy Resins; epoxy equivalent 255) and 182.7 parts of propylene glycol monomethyl ether acetate were added and dissolved to form a homogeneous solution. Next, 90.2 parts of methacrylic acid, 1.3 parts of triphenylphosphine as an esterification catalyst, and 0.6 parts of methylhydroquinone as a polymerization inhibitor were charged and reacted at 120 ° C for 20 hours. It was confirmed that the acid value of the reaction product was 2.9 mg KOH / g. Next, 131.7 parts of tetrahydrophthalic anhydride was added and the mixture was reacted at 110°C for 5 hours to obtain an alkali-soluble resin (A-2) containing 61% of a mixture of an acid-modified vinyl ester having an acid value of 90 mgKOH / g and a carboxyl group-containing bisphenol A type epoxy acrylate.

[0111] [Synthesis of alkali-soluble resin A-3] 120 parts of novolac cresol resin ("Shonol CRG-951" manufactured by Aica Kogyo, OH equivalent: 120), 1 part of potassium hydroxide, and 120 parts of toluene were introduced, and the system was purged with nitrogen while stirring and heated to an elevated temperature. Next, 64 parts of propylene oxide were gradually added dropwise, and the reaction was carried out at 130°C. After cooling to room temperature, 2 parts of 89% phosphoric acid were added and mixed to the reaction solution to neutralize the potassium hydroxide, yielding a propylene oxide reaction solution of novolac cresol resin with a nonvolatile content of 60% and a hydroxyl value of 180 mgKOH / g. 300 parts of the resulting propylene oxide reaction solution of novolac cresol resin, 40 parts of acrylic acid, 10 parts of methanesulfonic acid, 0.2 parts of methylhydroquinone, and 250 parts of toluene were introduced into a reactor equipped with a stirrer, thermometer, and air inlet tube, and the mixture was reacted at 110°C while stirring and blowing in air at a rate of 10 ml / min. The mixture was then cooled to room temperature, and the resulting reaction solution was neutralized with a 15% aqueous sodium hydroxide solution and then washed with water. The toluene was then distilled off using an evaporator while being replaced with 120 parts of diethylene glycol monoethyl ether acetate, yielding a novolac acrylate resin solution. Next, 300 parts of the obtained novolac type acrylate resin solution and 1 part of triphenylphosphine were introduced into a reactor equipped with a stirrer, a thermometer, and an air-inlet tube, and while blowing air at a rate of 10 ml / min and stirring, 60 parts of tetrahydrophthalic anhydride was gradually added and reacted at 100°C to obtain an alkali-soluble resin (A-3).

[0112] [Synthesis of alkali-soluble resin A-4] 450 parts of bisphenol A, 200 parts of water, and 650 parts of 37% formalin were charged, and 230 parts of 25% aqueous sodium hydroxide solution was added. After the reaction was completed, the mixture was cooled to 40°C and neutralized with 37% aqueous phosphoric acid solution. After separating the aqueous layer, 300 parts of methyl isobutyl ketone was added and uniformly dissolved, and then water and solvent were removed. The resulting polymethylol compound was dissolved in 550 parts of methanol to obtain 1,000 parts of a methanol solution of the polymethylol compound. A flask equipped with a condenser and a stirrer was charged with 500 parts of the resulting methanol solution of the polymethylol compound and 440 parts of 2,6-xylenol and uniformly dissolved. 8 parts of oxalic acid was then added, and the reaction was carried out at 100°C. After the reaction was completed, the distillate was removed at 180°C under a reduced pressure of 50 mmHg, yielding 550 parts of novolak resin A. An autoclave equipped with a thermometer, a nitrogen / alkylene oxide inlet, and a stirrer was charged with 130 parts of novolac resin A, 3 parts of a 50% aqueous sodium hydroxide solution, and 100 parts of a 2 / 1 toluene / methyl isobutyl ketone mixture. The system was purged with nitrogen while stirring, and then heated to 150°C. 60 parts of propylene oxide were gradually introduced at 8 kg / cm² to induce the reaction. The reaction was continued for approximately 4 hours, after which the mixture was cooled to room temperature. Three parts of a 36% aqueous hydrochloric acid solution were added and mixed to neutralize the sodium hydroxide. The neutralized reaction product was diluted with toluene, washed three times with water, and desolvated using an evaporator to obtain a propylene oxide adduct of novolac resin A with a hydroxyl value of 189 g / eq. This product had an average of 1 mole of propylene oxide added per equivalent of phenolic hydroxyl group. 189 parts of the resulting propylene oxide adduct of novolak resin A, 36 parts of acrylic acid, 3 parts of p-toluenesulfonic acid, 0.1 parts of hydroquinone monomethyl ether, and 140 parts of toluene were charged into a reactor equipped with a stirrer, thermometer, and air inlet tube, and the mixture was stirred while blowing in air. The temperature was raised to 115°C, and the reaction was continued for another 4 hours while distilling off the water produced by the reaction as an azeotrope with toluene. The mixture was then cooled to room temperature. The resulting reaction solution was washed with 5% aqueous NaCl, and the toluene was removed by distillation under reduced pressure to obtain a 7% acrylate resin solution.Next, 320 parts of the obtained acrylate resin solution, 0.1 parts of hydroquinone monomethyl ether, and 0.3 parts of triphenylphosphine were charged into a four-neck flask equipped with a stirrer and a reflux condenser, and this mixture was heated to 110°C. 60 parts of tetrahydrophthalic anhydride was added and reacted for 4 hours to obtain an alkali-soluble resin (A-4).

[0113] [Synthesis of alkali-soluble resin A-5] A separable flask equipped with a condenser was charged with 80 parts of carbitol acetate as a reaction vessel, and after purging with nitrogen, the temperature was raised to 80°C. Separately, a mixture of 30 parts of N-phenylmaleimide and 120 parts of carbitol acetate was charged into dropping vessel 1, a mixture of 30 parts of styrene and 20 parts of 2-hydroxyethyl methacrylate was charged into dropping vessel 2, a mixture of 20 parts of acrylic acid and 10 parts of carbitol acetate was charged into dropping vessel 3, and a mixture of 10 parts of Luperox 11 (Arkema Yoshitomi Co., Ltd., a hydrocarbon solution containing 70% t-butyl peroxypivalate) as a polymerization initiator and 20 parts of carbitol acetate was charged into dropping vessel 4. While maintaining the reaction temperature at 80°C, the mixture was added dropwise from the dropping vessel. After the completion of the dropwise addition, the reaction was continued at 80°C for an additional 30 minutes. The reaction temperature was then raised to 95°C, and the reaction was continued for 1.5 hours to obtain a polymer solution before the radical polymerizable double bond introduction reaction. Next, 10 parts of glycidyl methacrylate, 7 parts of carbitol acetate, 0.7 parts of triphenylphosphine as a reaction catalyst, and 0.2 parts of Antage W-400 (manufactured by Kawaguchi Chemical Industry Co., Ltd.) as a polymerization inhibitor were added to this polymer solution, and the mixture was reacted at 115°C while bubbling a mixed gas of nitrogen and oxygen (oxygen concentration 7%) to obtain alkali-soluble resin A-5.

[0114] [Preparation of inorganic particles C-1] A silica solvent dispersion was obtained by uniformly dispersing 60 g of spherical silica (SFP-30M manufactured by Denka, average particle size: 600 nm), 40 g of MEK (methyl ethyl ketone) as a solvent, and 1 g of a methacrylic silane coupling agent (KBM-503 manufactured by Shin-Etsu Chemical Co., Ltd.).

[0115] [Preparation of inorganic particles C-2] A silica solvent dispersion was obtained by uniformly dispersing 50 g of spherical silica (IX-3-NP manufactured by Nippon Shokubai Co., Ltd., average particle size 20 nm) prepared by the sol-gel method, 100 g of MEK (methyl ethyl ketone), and 20 g of an amino-silane coupling agent (KBE-573 manufactured by Shin-Etsu Chemical Co., Ltd.).

[0116] [Preparation of inorganic particles C-3] 70 g of a hydrotalcite compound (DHT-4C manufactured by Kyowa Chemical Industry Co., Ltd., average particle size 400 nm) was uniformly dispersed in 40 g of MEK (methyl ethyl ketone) as a solvent to obtain a hydrotalcite compound solvent dispersion C-3.

[0117] [Epoxy resin dispersion of rubber particles D-1] (Preparation of core-shell rubber particles with curable reactive groups on the surface) 1300 g of rubber latex and 440 g of purified water were placed in a 3-liter glass reactor and heated to 70°C with stirring under nitrogen. This rubber latex contained 480 g of polybutadiene particles with an average particle size of 0.1 μm and 1.5 mass% sodium dodecylbenzenesulfonate based on 100 mass% of the polybutadiene. 1.2 g of azoisobutyronitrile was added, followed by a mixture of 36 g of styrene, 48 g of methyl methacrylate, 24 g of acrylonitrile, and 12 g of glycidyl methacrylate over a period of 3 hours. The mixture was then stirred for an additional 2 hours to obtain core-shell rubber particles (latex (L)). The solids content of latex (L) was 32%. The gel fraction of the core-shell copolymer in latex (L) was 98%. The rubber particle diameter in latex (L) was 0.5 μm.

[0118] [Preparation of alkali-soluble resin composition] Each alkali-soluble resin obtained by the synthesis described above was adjusted with propylene glycol methyl ether acetate to a solids content of 60% to prepare a varnish solution (solids content shown in Table 1), which was then blended with an epoxy resin, inorganic particles, and other raw materials in the proportions (parts by mass) shown in Table 1. The mixture was premixed with a stirrer and then kneaded with a three-roll mill to prepare alkali-soluble resin compositions X-1 to X-10 for the X layer and alkali-soluble resin compositions Y-1 to Y-10 for the Y layer. [Table 1]

[0119] The notes in the headings of Table 1 are as follows: *1: Alkali-soluble resin A-1 synthesized above *2: Alkali-soluble resin A-2 synthesized above *3: Alkali-soluble resin A-3 synthesized above *4: Alkali-soluble resin A-4 synthesized above *5: Alkali-soluble resin A-5 synthesized above *6: Meiwa Kasei HF-1M, phenol novolac resin, hydroxyl equivalent 106 *7: Nissan Chemical TEPIC-VL, heterocyclic epoxy resin, trifunctional, liquid, epoxy equivalent: 128g / eq *8: Nippon Kayaku NC-3000H, biphenyl novolac epoxy resin, epoxy equivalent 290g / eq *9: DIC EPICLON HP7200L, dicyclopentadiene epoxy resin *10: Inorganic particles C-1 prepared above *11: Inorganic particles C-2 prepared above *12: Inorganic particle C-3 prepared above *13: Epoxy resin dispersion D-1 of rubber particles prepared above *14: DIC Polyester Polyol Polylite OD-X-2068 *15: Phenoxy resin YX7200B35 manufactured by Mitsubishi Chemical Corporation *16: Acylphosphine oxide photopolymerization initiator E-1, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide *17: Photopolymerization initiator E-2: Omnirad 907 (2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one) manufactured by IGM Resins *18: A-DCP (tricyclodecane dimethanol diacrylate) manufactured by Shin-Nakamura Chemical Co., Ltd.

[0120] (Examples 1 to 17, Comparative Examples 1 to 7) <Dry film preparation> Each alkali-soluble resin composition obtained as described above was diluted with 300 g of methyl ethyl ketone and stirred for 15 minutes with a mixer to obtain a coating solution. The coating solution was first applied to a 38 μm-thick polyethylene terephthalate film (hereinafter also referred to as PET film) (first film) so that the thickness ratio of the X layer to the Y layer was the same as that of Examples 1 to 17 and Comparative Examples 3, 5, and 6 in Table 2. The X layer was then dried at 80°C for 5 minutes in a hot air circulation drying oven. After cooling, the Y layer was applied on top of the X layer and then dried at 80°C for 15 minutes to form a laminated resin layer (two resin layers) with a total thickness of 25 μm. In Comparative Examples 1, 2, 4, and 7, a single layer was applied to a thickness of 25 μm, and the coating was dried at 80°C for 15 minutes. Next, a biaxially oriented polypropylene film (second film) was attached onto the laminated resin layer to prepare a dry film. The following tests and evaluations were carried out on the dry films of Examples 1 to 17 and Comparative Examples 1 to 7. The results are shown in Table 2.

[0121] <Crack resistance (heat and cold resistance) evaluation> The dry films of each of the examples and comparative examples prepared in the above <Dry Film Preparation> were CZ-treated onto a BT substrate with a 2 mm copper line pattern. After peeling off the second film, each dry film was laminated in a first chamber at 80°C using a vacuum laminator (CVP-600: manufactured by Nikko Materials Co., Ltd.) under conditions of a vacuum pressure of 3 hPa and a vacuum time of 30 seconds, followed by pressing under conditions of a press pressure of 0.5 MPa and a press time of 30 seconds to obtain an evaluation substrate. After exposure to an exposure dose sufficient to obtain 10 steps on a step tablet (41 steps) using a DI exposure machine (Example 6 only after 40 minutes of thermal drying at 80°C), the PET film was peeled off, and development (1 mass% Na2CO3, 30°C, 0.2 MPa) was carried out for 60 seconds to form a resin layer pattern. Subsequently, a UV conveyor furnace equipped with a high-pressure mercury lamp was used to laminate the dry films under conditions of 1 J / cm2. 2 After irradiating the resin layer with an exposure dose of 1000, the resin layer was heated at 160°C for 60 minutes to completely harden, and an evaluation substrate was fabricated with a 3mm square resist pattern formed on the copper line. This substrate was placed in a thermal cycler that cycles temperatures between -50°C and 150°C, and a TCT (Thermal Cycle Test) was performed. The occurrence of cracks was confirmed after evaluation up to 1000 cycles. ◎: No cracks occurred up to 2000 cycles. 〇: No cracks occurred after 1500 cycles. △: Cracks occurred within 1500 cycles. ×: Cracks occurred within 1000 cycles.

[0122] <Resolution (shape sharpness)> The dry films of each Example and Comparative Example prepared in the above <Dry Film Preparation> were applied to the copper of a CZ-treated copper-clad laminate, after peeling off the second film. The dry films were then laminated in a first chamber at 100°C using a vacuum laminator (CVP-600, manufactured by Nikko Materials Co., Ltd.) under conditions of a vacuum pressure of 3 hPa and a vacuum time of 30 seconds, followed by pressing under conditions of a pressure of 0.5 MPa and a press time of 30 seconds to obtain evaluation substrates. Subsequently, a φ30 μm SRO pattern was exposed using a projection exposure machine (i-line) at an exposure dose sufficient to obtain 10 steps on a step tablet (41 steps) (Example 6 was subjected to thermal drying at 80°C for 40 minutes). The PET film was then peeled off, and development (1% by mass Na2CO3, 30°C, 0.2 MPa) was carried out for 60 seconds to form a resin layer pattern. Subsequently, the film was laminated in a UV conveyor furnace equipped with a high-pressure mercury lamp at 1 J / cm2. 2 After irradiating the resin layer with an exposure dose of 1000, the resin layer was completely cured by heating at 160°C for 60 minutes to produce an evaluation substrate with a patterned cured film, and the shape of the shoulder at the top of the opening was observed at 3000x magnification using an SEM. ◎: The top shoulder has a sharp shape. 〇: The shoulders of the top are slightly rounded. △: The shoulders of the top are rounded. ×: The shoulders of the top are rounded or loose and not sharp.

[0123] <Metal plating adhesion evaluation> The dry films of each of the Examples and Comparative Examples prepared in the above <Preparation of Dry Film> were laminated onto acid-treated FR-4 using a vacuum laminator (CVP-600: manufactured by Nikko Materials Co., Ltd.) under conditions of a vacuum pressure of 3 hPa and a vacuum time of 30 seconds at 80°C, followed by pressing under conditions of a pressure of 0.5 MPa and a pressing time of 30 seconds to obtain evaluation substrates. After exposure using a contact exposure machine (Example 6 only: after 40 minutes of thermal drying at 80°C), the PET film was peeled off, and development (1 mass% Na2CO3, 30°C, 0.2 MPa) was carried out for 60 seconds, followed by irradiation with 1 J / cm2 in a UV conveyor oven equipped with a high-pressure mercury lamp. 2After irradiating the resin layer with an exposure amount of 1000 ppm, the resin layer was heated at 160° C. for 60 minutes to completely harden the resin layer, thereby preparing an evaluation substrate. The resin layer was subjected to a commercially available wet permanganate desmear process, followed by electroless copper plating and electrolytic copper plating, all under the same conditions, to a copper plating thickness of 25 μm. The test substrate was then annealed in a hot air circulating oven at 190°C for 60 minutes to obtain a test substrate. A 25-square grid measuring 1 mm x 1 mm was created on the copper-plated surface of the test substrate using a utility knife (JIS-K5600-5-6 1999, Adhesion (Cross-Cut Method)). Polyester tape (product number 9394, adhesive strength 3.3 N / cm, 3M) was then applied to the surface of the cut cured film. The edge of the tape was immediately held perpendicular to the cured film surface and the tape was instantly peeled off. The condition of the coating after peeling was evaluated according to the following criteria. ◎: Less than one square peeled off. ○: Peeled off in 1 or more but less than 5 places. △: Peeled off in 5 or more but less than 10 places. ×: More than 10 squares peeled off.

[0124] [Table 2]

[0125] [Table 3]

[0126] The results shown in Tables 2 and 3 indicate that the cured laminated curable resin structures of Examples 1 to 17 were excellent in crack resistance (cold and heat resistance), resolution (shape sharpness), and metal plating adhesion. In contrast, the cured laminated curable resin structures of each Comparative Example were poor in at least one of crack resistance (cold and heat resistance), resolution (shape sharpness), and metal plating adhesion. Specifically, Comparative Example 1 had a single-layer structure consisting of only the X-1 layer and was poor in crack resistance (cold and heat resistance). Comparative Example 2 had a single-layer structure consisting of only the Y-1 layer and was poor in resolution (shape sharpness) and metal plating adhesion. Comparative Example 3 had a thickness of the X layer greater than the thickness of the Y layer and was poor in crack resistance (cold and heat resistance). Comparative Example 4 had a single-layer structure consisting of only the X-10 layer, which did not contain hydrotalcite in the X layer, and was poor in crack resistance (cold and heat resistance) and metal plating adhesion. Comparative Example 5 is an example in which the Y layer did not contain silica, and the crack resistance (cold and heat resistance) was poor. Comparative Example 6 is an example in which the ratio of the thickness of the X layer to the total thickness of the resin composition including the X layer and the Y layer was too high, and the crack resistance (cold and heat resistance) and resolution (shape sharpness) were poor. Comparative Example 7 is an example in which the Y layer had a single-layer structure consisting of only the Y-8 layer, which did not contain rubber particles or elastomer, and the crack resistance (cold and heat resistance) and metal plating adhesion were poor.

[0127] Fig. 2 shows a sketch of an SEM photograph in which the resolution (shape sharpness) of Example 1 was evaluated, and Fig. 3 shows a sketch of an SEM photograph in which the resolution (shape sharpness) of Comparative Example 2 was evaluated. In Example 1, the shoulder of the opening in X layer 11X of the laminated curable resin structure was sharp, whereas in Comparative Example 2, the shoulder of the opening in curable resin 111 was rounded. In Figs. 2 and 3, reference numeral 14 denotes a copper-clad laminate. [Explanation of symbols]

[0128] 1 dry film 11 Laminated curable resin structure 11X X layer 11Y Y layer 12 First Film 13 Second Film 14 Copper-clad laminate 111 Curing resin

Claims

1. the resin film is composed of two resin layers, that is, an X layer made of an alkali-soluble resin composition X and a Y layer made of an alkali-soluble resin composition Y, laminated together, and the X layer accounts for 5% to 30% of the total thickness of the two resin layers combined with the Y layer; the alkali-soluble resin compositions X and Y of the X layer and the Y layer each contain inorganic particles, and the inorganic particles of the X layer are inorganic particles containing a metal element having O, S, or N in its coordination electrons, and the inorganic particles are contained in an amount of less than 20 mass % relative to the total solid content of the alkali-soluble resin composition X of the X layer; The inorganic particles of the Y layer contain silica, and the content of the silica is 25% by mass or more and less than 50% by mass with respect to the total solid content of the alkali-soluble resin composition Y of the Y layer. A laminated curable resin structure characterized by:

2. 2. The laminated curable resin structure according to claim 1, wherein the alkali-soluble resin compositions X and Y of the X layer and the Y layer each further comprise at least one selected from the group consisting of a radically polymerizable compound and an epoxy resin.

3. The laminated curable resin structure according to claim 1, wherein the alkali-soluble resin compositions X and Y of the X layer and the Y layer each contain at least one selected from rubber particles having an average particle size of 100 nm or more and 1 μm or less and a thermoplastic elastomer.

4. 4. The laminated curable resin structure according to claim 1, wherein the alkali-soluble resin compositions X and Y of the X layer and the Y layer each contain a curing accelerator.

5. A dry film comprising a resin layer obtained by applying the laminated curable resin structure according to any one of claims 1 to 3 to a film and drying the applied film.

6. A cured product obtained by curing the resin layer of the laminated curable resin structure according to any one of claims 1 to 3.

7. A cured product obtained by curing the resin layer of the dry film according to claim 5.

8. An electronic part comprising the cured product according to claim 6.

9. An electronic part comprising the cured product according to claim 7.

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