Laminated structure, cured product and printed wiring board

Abstract

To provide a laminated structure that enables formation of a cured product that achieves both high dielectric constant and good resolution, and suppresses scattering of light during light exposure.SOLUTION: A laminated structure includes a first film, a first resin layer and a second resin layer, where the first film, the first resin layer and the second resin layer are laminated in this order. A carboxyl group-containing resin, a photopolymerization initiator and a thermosetting component are blended with the first resin layer. The carboxyl group-containing resin, the photopolymerization initiator, the thermosetting component, a perovskite type compound, silica and a photocurable compound containing no carboxyl group are blended with the second resin layer. A content of a filler in the first resin layer is adjusted to 0 to 10 vol.% in terms of solid content, and a content of the perovskite type compound in the second resin layer is adjusted to 25 to 55 vol.% in terms of solid content. When the content of the filler in the first resin layer exceeds 0 vol.%, a refractive index of the filler is adjusted to less than 2.2.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a laminate structure including a resin layer, particularly to a laminate structure suitable for use in forming a solder resist layer. The present invention also relates to a cured product of the resin layer of the laminate structure and a printed wiring board including the cured product. [Background technology]

[0002] Biometric authentication has been used as a personal authentication tool in various fields. In particular, in recent years, fingerprint authentication has been used in many mobile devices, and as a result, mobile devices equipped with fingerprint detection devices have become mainstream. In particular, mobile devices that store personal information (e.g., smartphones) require high-precision fingerprint authentication, and most such mobile devices employ capacitive fingerprint detection devices (fingerprint authentication sensors).

[0003] The operating principle of a capacitive fingerprint detection device is that electrodes read the difference in charge generated within the device due to the unevenness of a fingerprint, thereby recognizing the fingerprint.Currently, fingerprint detection devices generally use FC-BGA (Flip Chip-Ball Grid Array) substrates, which have build-up layers on both sides of a core layer.The build-up layer on the outer surface (top side) of the fingerprint detection device forms the sensor, and the build-up layer on the inner surface (bottom side) of the fingerprint detection device is where electronic components such as IC chips are mounted and solder balls are arranged.A solder resist layer is then formed on each of the build-up layers on the top and bottom sides.

[0004] Because such fingerprint detection devices require high fingerprint authentication accuracy, attempts have been made to improve the resolution and dielectric constant of the solder resist layers formed on the top and bottom build-up layers of FC-BGA substrates to improve the fingerprint readability of the sensor. Typically, to improve the resolution and dielectric constant of the solder resist layer, the type and content of carboxyl-containing resin, carboxyl-free photocurable compound, and / or photopolymerization initiator in the resin composition used to form the solder resist layer are adjusted. For example, Patent Document 1 proposes blending at least two perovskite-type compounds, one of which is barium titanate, into the resin composition used to form the solder resist in order to improve the resolution and dielectric constant while maintaining the reliability of the solder resist layer, such as its HAST resistance.

[0005] However, in order to increase the dielectric constant of the solder resist layer, a relatively large amount of inorganic filler with a high dielectric constant, such as barium titanate, must be blended into the resin composition. It is known that increasing the content of inorganic filler in the resin composition deteriorates the deep curing of the resulting solder resist layer, resulting in an inversely tapered cross-sectional shape of the solder resist layer after development, making it difficult to improve resolution. In other words, there is a trade-off between increasing the content of inorganic filler with a high dielectric constant in the solder resist layer and improving resolution. To resolve this trade-off, for example, Patent Document 2 proposes using a combination of barium titanate and zirconium oxide as fillers. Patent Document 3 also proposes combining zirconium dioxide particles with two types of epoxy (meth)acrylate resins having specific structures. However, the limited fillers and resins used limit the composition of the resin composition, making it difficult to obtain a resin composition with desired properties.

[0006] On the other hand, it has also been proposed to incorporate a surface-treated perovskite compound as a filler into a resin composition and adjust its content higher than usual. However, since perovskite compounds generally have a high refractive index, resin compositions with a high content of perovskite compounds have the problem of light refraction during exposure. In particular, in dry films in which a resin layer made of a dried coating film of such a resin composition is laminated with a PET film, light is severely refracted during exposure, and the repeatedly refracted light is further scattered within the PET film, causing halation, which necessitates peeling off the PET film before exposure. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 2017-37287 [Patent Document 2] International Publication No. 2013 / 161968 Brochure [Patent Document 3] International Publication No. 2018 / 21497 Brochure Summary of the Invention [Problem to be solved by the invention]

[0008] Under these circumstances, a technical challenge exists to provide a laminate structure that includes a resin layer and a film that can form a cured product that has both a high dielectric constant and good resolution, and that suppresses light scattering during exposure.

[0009] Therefore, an object of the present invention is to provide a laminate structure including a resin layer and a film that can form a cured product that has both a high dielectric constant and good resolution, and that suppresses light scattering during exposure. Another object of the present invention is to provide a cured product that has both a high dielectric constant and good resolution, obtained by curing the resin layer of such a laminate structure, and a printed wiring board that includes the cured product. [Means for solving the problem]

[0010] As a result of extensive research, the present inventors have discovered that the above-mentioned problems can be solved by laminating the first film, first resin layer, and second resin layer in this order in a laminate structure comprising a first film, a first resin layer, and a second resin layer; blending a carboxyl group-containing resin, a photopolymerization initiator, and a thermosetting component in the first resin layer; blending a carboxyl group-containing resin, a photopolymerization initiator, a thermosetting component, a perovskite compound, silica, and a carboxyl-free photosetting compound in the second resin layer; adjusting the filler content in the first resin layer to 0-10% by volume, calculated as solids; adjusting the perovskite compound content in the second resin layer to 25-55% by volume, calculated as solids; and, when the filler content in the first resin layer is greater than 0% by volume, adjusting the refractive index of the filler to less than 2.2. The present invention is based on this discovery. Specifically, the gist of the present invention is as follows.

[0011] [1] A laminated structure comprising a first film, a first resin layer, and a second resin layer, the first film, the first resin layer, and the second resin layer are laminated in this order; the first resin layer contains a carboxyl group-containing resin, a photopolymerization initiator, and a thermosetting component; the second resin layer contains a carboxyl group-containing resin, a photopolymerization initiator, a thermosetting component, a perovskite compound, silica, and a photosetting compound that does not contain a carboxyl group; the content of the filler in the first resin layer is 0 to 10% by volume in terms of solid content; the content of the perovskite compound in the second resin layer is 25 to 55% by volume in terms of solid content; When the content of the filler in the first resin layer exceeds 0% by volume, the refractive index of the filler is less than 2.2. The laminated structure characterized in that: [2] The laminate structure according to [1], wherein the perovskite compound includes a perovskite compound having a refractive index of 2.2 to 2.8. [3] The laminate structure according to [1] or [2], wherein the content of the perovskite compound in the second resin layer is 30 to 55% by volume in terms of solid content. [4] The laminate structure according to any one of [1] to [3], wherein the perovskite compound includes at least one compound selected from the group consisting of barium titanate, calcium titanate, and strontium titanate. [5] The laminate structure according to any one of [1] to [4], wherein the perovskite compound is surface-treated with one or more coupling agents selected from the group consisting of silane coupling agents and titanate coupling agents. [6] A cured product obtained by curing the first resin layer and the second resin layer of the laminate structure according to any one of [1] to [5]. [7] A printed wiring board comprising the cured product according to [6]. [Effects of the Invention]

[0012] According to the present invention, it is possible to provide a laminate structure including a resin layer and a film that can form a cured product that has both a high dielectric constant and good resolution, and in which light scattering during exposure is suppressed. Furthermore, according to the present invention, it is possible to provide a cured product that has both a high dielectric constant and good resolution, obtained by curing the resin layer of such a laminate structure, and a printed wiring board that includes the cured product. In particular, according to the present invention, it is possible to achieve both a high dielectric constant and good resolution in the cured product of the resin layer, which have traditionally been considered difficult to achieve, and further it is possible to suppress light scattering when the laminate structure is exposed to light. DETAILED DESCRIPTION OF THE INVENTION

[0013] [Laminated structure] According to one aspect of the present invention, there is provided a laminate structure (hereinafter also referred to as "the laminate structure of the present invention"). The laminate structure of the present invention comprises a first film, a first resin layer, and a second resin layer, the first film, the first resin layer, and the second resin layer being laminated in this order. Furthermore, in the laminate structure of the present invention, the first resin layer contains a carboxyl group-containing resin, a photopolymerization initiator, and a thermosetting component, and the second resin layer contains a carboxyl group-containing resin, a photopolymerization initiator, a thermosetting component, a perovskite compound, silica, and a photosetting compound that does not contain a carboxyl group. The content of the filler in the first resin layer is adjusted to a specific range, the content of the perovskite compound in the second resin layer is adjusted to a specific range, and when the content of the filler in the first resin layer is greater than 0% by volume, the refractive index of the filler is adjusted to be within a specific range. The laminate structure of the present invention, having such a configuration, can produce a cured product that has both a high dielectric constant and good resolution when exposed to light. In particular, even when the first film is not peeled off, light scattering can be suppressed, thereby preventing a decrease in the resolution of the cured product. Thus, the laminate structure of the present invention can form a cured product with high resolution even when the first film is not peeled off, so that a cured product that has both a high dielectric constant and good resolution and a printed wiring board including the cured product can be efficiently produced. In other words, the laminate structure of the present invention can be suitably used as a dry film for efficiently forming an insulating layer, particularly an insulating layer with a high dielectric constant, on the surface of a printed wiring board with high resolution.

[0014] Each element constituting the laminated structure of the present invention will be described in detail below. <First resin layer> The laminate structure of the present invention comprises a first resin layer containing a carboxyl group-containing resin, a photopolymerization initiator, and a thermosetting component. The first resin layer is composed of a dried coating of a resin composition and serves to suppress light scattering when the laminate structure of the present invention is exposed to light. When a printed wiring board is manufactured using the laminate structure of the present invention, the first resin layer is typically located on the opposite side of the substrate constituting the printed wiring board, via a second resin layer. The laminate structure of the present invention comprises a second resin layer containing a large amount of a perovskite compound having a relatively high refractive index, so light is severely refracted in the second resin layer. Therefore, in the absence of the first resin layer, light amplified by the severe refraction in the second resin layer would directly reach the first film. However, the structure of the present invention comprises a first resin layer between the second resin layer and the first film in addition to the second resin layer, thereby preventing refracted light generated in the second resin layer during exposure from reaching the first film. Therefore, even when the laminated structure of the present invention is exposed to light without peeling off the first film, halation caused by refracted light generated in the second resin layer being scattered within the first film can be suppressed, thereby suppressing a decrease in the resolution of the cured product. The reason why providing a first resin layer in addition to a second resin layer can suppress halation caused by refracted light generated in the second resin layer being scattered within the first film is unclear, but it is inferred as follows. That is, by providing a first resin layer with a relatively low refractive index between the second resin layer, which contains a perovskite compound and therefore has a relatively high refractive index, and the first resin layer, the first resin layer absorbs the refracted light generated in the second resin layer (i.e., prevents it from reaching the first film), thereby suppressing halation caused by refracted light being scattered within the first film. The components of the first resin layer are described in detail below.

[0015] (Carboxyl group-containing resin) As the carboxyl group-containing resin, various conventionally known resins having a carboxyl group in the molecule can be used. By including a carboxyl group-containing resin in the first resin layer, alkali developability can be imparted to the first resin layer. In particular, from the viewpoint of the photocurability and development resistance of the first resin layer, a photosensitive carboxyl group-containing resin having an ethylenically unsaturated double bond in the molecule is preferred. The ethylenically unsaturated double bond in the molecule constituting the carboxyl group-containing resin is preferably derived from acrylic acid, methacrylic acid, or a derivative thereof. When using only a carboxyl group-containing resin without an ethylenically unsaturated double bond, a photocurable compound not containing a carboxyl group, as described below, must be used in combination to render the first resin layer photocurable.

[0016] Specific examples of the carboxyl group-containing resin include the following compounds (which may be either oligomers or polymers): The carboxyl group-containing resins may be used alone or in combination of two or more.

[0017] (1) Carboxyl group-containing 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.

[0018] (2) Carboxylic acid-containing urethane resins obtained by the polyaddition reaction of diisocyanates such as aliphatic diisocyanates, branched aliphatic diisocyanates, alicyclic diisocyanates, and aromatic diisocyanates with carboxyl-containing dialcohol compounds such as dimethylolpropionic acid and dimethylolbutanoic acid, and diol compounds such as polycarbonate polyols, polyether polyols, polyester polyols, polyolefin polyols, acrylic polyols, bisphenol A alkylene oxide adduct diols, and compounds having phenolic hydroxyl groups and alcoholic hydroxyl groups.

[0019] (3) Carboxylic acid group-containing photosensitive urethane resins obtained by the polyaddition reaction of diisocyanates with bifunctional epoxy resins such as bisphenol A epoxy resins, hydrogenated bisphenol A epoxy resins, bisphenol F epoxy resins, bisphenol S epoxy resins, bixylenol epoxy resins, and biphenol epoxy resins, and monocarboxylic acid compounds having ethylenically unsaturated double bonds such as (meth)acrylic acid, partially acid anhydride-modified products thereof, carboxyl group-containing dialcohol compounds, and diol compounds.

[0020] (4) A carboxyl group-containing photosensitive urethane resin that is (meth)acrylated at the terminal by adding a compound having one hydroxyl group and one or more (meth)acryloyl groups in the molecule, such as hydroxyalkyl (meth)acrylate, during the synthesis of the resin (2) or (3) described above.

[0021] (5) A carboxyl group-containing photosensitive urethane resin that has been (meth)acrylated at the end by adding a compound having one isocyanate group and one or more (meth)acryloyl groups in the molecule, such as an equimolar reaction product of isophorone diisocyanate and pentaerythritol triacrylate, during the synthesis of the resin (2) or (3) described above.

[0022] (6) A carboxyl group-containing photosensitive resin obtained by reacting a difunctional or more polyfunctional (solid) epoxy resin with (meth)acrylic acid and adding a dibasic acid anhydride to the hydroxyl group present in the side chain.

[0023] (7) A carboxyl group-containing photosensitive resin in which the hydroxyl groups of a bifunctional (solid) epoxy resin are further epoxidized with epichlorohydrin to form a multifunctional epoxy resin, which is then reacted with (meth)acrylic acid, and a dibasic acid anhydride is added to the resulting hydroxyl groups.

[0024] (8) Carboxyl group-containing polyester resins obtained by reacting a dicarboxylic acid such as adipic acid, phthalic acid, or hexahydrophthalic acid with a bifunctional oxetane resin, and then adding a dibasic acid anhydride such as phthalic anhydride, tetrahydrophthalic anhydride, or hexahydrophthalic anhydride to the resulting primary hydroxyl groups.

[0025] (9) A carboxyl group-containing photosensitive resin obtained by reacting an epoxy compound having multiple epoxy groups in one molecule with a compound having at least one alcoholic hydroxyl group and one phenolic hydroxyl group in one molecule, such as p-hydroxyphenethyl alcohol, and an unsaturated 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 acid.

[0026] (10) A carboxyl group-containing photosensitive resin obtained by reacting a compound having multiple phenolic hydroxyl groups in one molecule with an alkylene oxide such as ethylene oxide or propylene oxide, reacting the resulting reaction product with an unsaturated group-containing monocarboxylic acid, and then reacting the resulting reaction product with a polybasic acid anhydride.

[0027] (11) A carboxyl group-containing photosensitive resin obtained by reacting a compound having multiple phenolic hydroxyl groups in one molecule with a cyclic carbonate compound such as ethylene carbonate or propylene carbonate, 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] (12) A carboxyl group-containing photosensitive resin obtained by adding a compound having one epoxy group and one or more (meth)acryloyl groups in one molecule to the resins (1) to (11). In this specification, (meth)acrylate is a general term for acrylate, methacrylate and mixtures thereof, and the same applies to other similar expressions.

[0029] The acid value of the carboxyl group-containing resin is preferably 30 to 150 mgKOH / g, more preferably 50 to 120 mgKOH / g. When the acid value of the carboxyl group-containing resin is 30 mgKOH / g or more, the alkali developability of the first resin layer can be improved. On the other hand, when the acid value of the carboxyl group-containing resin is 150 mgKOH / g or less, dissolution of the exposed area by a developer and subsequent indistinguishable dissolution and peeling of the exposed and unexposed areas can be suppressed, facilitating the drawing of a good resist pattern.

[0030] The weight-average molecular weight of the carboxyl group-containing resin varies depending on the resin skeleton, but is generally preferably 2,000 to 150,000, and more preferably 5,000 to 100,000. A weight-average molecular weight of 2,000 or more of the carboxyl group-containing resin can suppress a decrease in the moisture resistance of the cured product after exposure of the first resin layer and the accompanying film loss during development, thereby suppressing a decrease in the resolution of the cured product. On the other hand, a weight-average molecular weight of 150,000 or less of the carboxyl group-containing resin can improve the developability and storage stability of the first resin layer. The weight-average molecular weight of the carboxyl group-containing resin can be determined by gel permeation chromatography (GPC) using a standard polystyrene equivalent.

[0031] The content of the carboxyl group-containing resin in the first resin layer is preferably 10 to 60 mass %, more preferably 20 to 50 mass %, calculated as solid content, relative to the total mass of the first resin layer. By making the content of the carboxyl group-containing resin in the first resin layer 10 mass % or more, the coating strength of the first resin layer can be improved. On the other hand, by making the content of the carboxyl group-containing resin in the first resin layer 60 mass % or less, the viscosity of the resin composition constituting the first resin layer becomes appropriate, and processability can be improved.

[0032] (Photopolymerization initiator) Any known photopolymerization initiator can be used. The photopolymerization initiator may be used alone or in combination of two or more.

[0033] 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, and bis-(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide. Sphingoxide, bisacylphosphine oxides such as bis-(2,6-dimethoxybenzoyl)-2,5-dimethylphenylphosphine oxide and bis-(2,4,6-trimethylbenzoyl)-phenylphosphine oxide; 2,6-dimethoxybenzoyldiphenylphosphine oxide, 2,6-dichlorobenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoylphenylphosphinic acid methyl ester, 2-methylbenzoyldiphenylphosphine oxide, pivaloylphenyl Monoacylphosphine oxides such as phosphinic acid isopropyl ester and 2,4,6-trimethylbenzoyldiphenylphosphine oxide; ethyl phenyl(2,4,6-trimethylbenzoyl)phosphinate, 1-hydroxy-cyclohexyl phenyl ketone, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-propan-1-one hydroxyacetophenones such as 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-[4-(4-morpholinyl)phenyl]-1- Acetophenones such as 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-tert-butylanthraquinone, 1-chloroanthraquinone, 2-amylanthraquinone anthraquinones such as acetophenone dimethyl ketal and 2-aminoanthraquinone; ketals such as acetophenone dimethyl ketal and benzil 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)phenyl]-, 2-(O-benzoyloxime), ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, 1-(O- acetyl oxime); titanocenes such as bis(η5-2,4-cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrol-1-yl)phenyl)titanium and bis(cyclopentadienyl)-bis[2,6-difluoro-3-(2-(1-pyr-1-yl)ethyl)phenyl]titanium; phenyl disulfide 2-nitrofluorene, butyroin, anisoin ethyl ether, azobisisobutyronitrile, tetramethylthiuram disulfide, etc. Among these, oxime esters (oxime ester-based photopolymerization initiators) are preferably used.

[0034] The content of the oxime ester photopolymerization initiator in the first resin layer is preferably 0.1 to 40 parts by mass, more preferably 0.1 to 20 parts by mass, calculated as solids content, per 100 parts by mass of the carboxyl group-containing resin. By setting the content of the oxime ester photopolymerization initiator in the first resin layer to 0.1 parts by mass or more per 100 parts by mass of the carboxyl group-containing resin, the photocurability of the first resin layer can be improved, and further, coating properties such as heat resistance and chemical resistance can be improved. On the other hand, by setting the content of the oxime ester photopolymerization initiator in the first resin layer to 40 parts by mass or less per 100 parts by mass of the carboxyl group-containing resin, light absorption at the surface of the first resin layer can be improved, and as a result, a decrease in deep curability can be suppressed.

[0035] A photoinitiator aid or sensitizer may be used in combination with the above-mentioned photopolymerization initiator. Examples of the photoinitiator aid or sensitizer include benzoin compounds, anthraquinone compounds, thioxanthone compounds, ketal compounds, benzophenone compounds, tertiary amine compounds, and xanthone compounds. As the photoinitiator aid or sensitizer, thioxanthone compounds such as 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, 2-isopropylthioxanthone, and 4-isopropylthioxanthone are particularly preferred. The inclusion of a thioxanthone compound in the first resin layer can improve deep curing properties. While these compounds may be used as photopolymerization initiators, they are preferably used in combination with a photopolymerization initiator. Furthermore, the photoinitiator aid or sensitizer may be used alone or in combination of two or more.

[0036] These photopolymerization initiators, photoinitiator assistants, and sensitizers absorb specific wavelengths, which can reduce sensitivity in some cases and function as ultraviolet absorbers. However, they are not used solely for the purpose of improving the sensitivity of the composition. By absorbing light of specific wavelengths as needed, they can increase the photoreactivity of the surface, change the line shape and opening of the resist to vertical, tapered, or reverse tapered, and improve the accuracy of the line width and opening diameter.

[0037] (thermosetting component) Examples of thermosetting components that can be used include known thermosetting components such as amino resins such as melamine resins, benzoguanamine resins, melamine derivatives, and benzoguanamine derivatives, isocyanate compounds, blocked isocyanate compounds, cyclocarbonate compounds, epoxy compounds, oxetane compounds, episulfide resins, bismaleimides, and carbodiimide resins. It is particularly preferable to use a thermosetting component having multiple cyclic ether groups or cyclic thioether groups (hereinafter abbreviated as cyclic (thio)ether groups) in the molecule. By including a thermosetting component in the first resin layer, it is expected that the heat resistance of the first resin layer will be improved. One type of thermosetting component may be used alone, or two or more types may be used in combination.

[0038] The thermosetting component having multiple cyclic (thio)ether groups in the molecule is a compound having multiple 3-, 4-, or 5-membered cyclic (thio)ether groups in the molecule, and examples thereof include a compound having multiple epoxy groups in the molecule, i.e., a polyfunctional epoxy compound; a compound having multiple oxetanyl groups in the molecule, i.e., a polyfunctional oxetane compound; and a compound having multiple thioether groups in the molecule, i.e., an episulfide resin.

[0039] Examples of polyfunctional epoxy compounds include epoxidized vegetable oils, bisphenol A epoxy resins, hydroquinone epoxy resins, bisphenol epoxy resins, thioether epoxy resins, brominated epoxy resins, novolac epoxy resins, biphenol novolac epoxy resins, bisphenol F epoxy resins, hydrogenated bisphenol A epoxy resins, glycidylamine epoxy resins, hydantoin epoxy resins, alicyclic epoxy resins, trihydroxyphenylmethane epoxy resins, and bixylenol or biphenol epoxy resins. or mixtures thereof; bisphenol S type epoxy resin; bisphenol A novolac type epoxy resin; tetraphenylolethane type epoxy resin; heterocyclic epoxy resin; diglycidyl phthalate resin; tetraglycidyl xylenoylethane resin; naphthalene group-containing epoxy resin; epoxy resin having a dicyclopentadiene skeleton; glycidyl methacrylate copolymer epoxy resin; cyclohexylmaleimide and glycidyl methacrylate copolymer epoxy resin; epoxy-modified polybutadiene rubber derivative; CTBN-modified epoxy resin, etc. The epoxy resin may be used alone or in combination of two or more.

[0040] Examples of polyfunctional oxetane compounds include bis[(3-methyl-3-oxetanylmethoxy)methyl]ether, bis[(3-ethyl-3-oxetanylmethoxy)methyl]ether, 1,4-bis[(3-methyl-3-oxetanylmethoxy)methyl]benzene, 1,4-bis[(3-ethyl-3-oxetanylmethoxy)methyl]benzene, (3-methyl-3-oxetanyl)methyl acrylate, and (3-ethyl-3-oxetanyl)methyl acrylate. Examples of suitable oxetane compounds include polyfunctional oxetanes such as acrylate, (3-methyl-3-oxetanyl)methyl methacrylate, (3-ethyl-3-oxetanyl)methyl methacrylate, and their oligomers or copolymers, as well as ethers of oxetane alcohols with novolak resins, poly(p-hydroxystyrene), cardo-type bisphenols, calixarenes, calixresorcinarenes, or hydroxyl group-containing resins such as silsesquioxane. Other examples include copolymers of unsaturated monomers having an oxetane ring and alkyl (meth)acrylates.

[0041] Examples of compounds having multiple cyclic thioether groups in the molecule include bisphenol A episulfide resins. Furthermore, episulfide resins in which the oxygen atoms of the epoxy groups of novolac epoxy resins are replaced with sulfur atoms can also be used using a similar synthesis method.

[0042] The content of the thermosetting component in the first resin layer is preferably an amount such that the number of functional groups of the thermosetting component that reacts with 1 mol of carboxyl groups contained in the carboxyl group-containing resin of the first resin layer is 0.1 to 10.0 mol, more preferably 0.2 to 5.0 mol.

[0043] (First filler) The first resin layer may contain a filler (also referred to herein as a "first filler") as needed to increase the physical strength of the cured product. Known inorganic or organic fillers with a refractive index of less than 2.2 can be used as the first filler, with barium sulfate, spherical silica, hydrotalcite, and talc being particularly preferred. Furthermore, various metal oxides and metal hydroxides (e.g., aluminum hydroxide) can be used as the first filler to achieve a white appearance and flame retardancy.

[0044] The refractive index of the first filler is less than 2.2, preferably 1.8 or less, and more preferably 1.0 or more and 1.6 or less.

[0045] As described above, the first resin layer may contain a first filler if necessary, but may not contain a first filler. Specifically, the content of the first filler in the first resin layer is 0 to 10% by volume, calculated as solid content, relative to the total volume of the first resin layer. Preferably, the first resin layer does not contain the first filler (i.e., the first filler content is 0% by volume). When the first resin layer does not contain the first filler (i.e., the first filler content is 0% by volume), or when the first resin layer contains the first filler (i.e., the first filler content is greater than 0% by volume) and the refractive index of the first filler is less than 2.2, refracted light generated in the second resin layer (described below) is prevented from reaching the first film during exposure of the laminate structure of the present invention, thereby suppressing halation caused by scattering of the refracted light in the first film and improving the resolution of the cured product.

[0046] (Photocurable compound not containing a carboxyl group) The first resin layer may contain a photocurable compound that does not contain a carboxyl group, if necessary. The photocurable compound that does not contain a carboxyl group is not particularly limited as long as it is a photocurable resin having a chemical structure that does not contain a carboxyl group, and for example, a compound having multiple ethylenically unsaturated groups in the molecule is used. Examples of photocurable compounds that do not contain a carboxyl group include photopolymerizable oligomers and photopolymerizable monomers. Of these, photopolymerizable monomers are preferably used from the viewpoint of further improving the crosslinkability and curability of the cured product of the first resin layer.

[0047] Examples of photopolymerizable oligomers include unsaturated polyester oligomers and (meth)acrylate oligomers. Examples of (meth)acrylate oligomers include epoxy (meth)acrylates such as phenol novolac epoxy (meth)acrylate, cresol novolac epoxy (meth)acrylate, and bisphenol-type epoxy (meth)acrylate, as well as urethane (meth)acrylate, epoxy urethane (meth)acrylate, polyester (meth)acrylate, polyether (meth)acrylate, and polybutadiene-modified (meth)acrylate. One type of photopolymerizable oligomer may be used alone, or two or more types may be used in combination.

[0048] Examples of photopolymerizable monomers include commonly known polyester (meth)acrylates, polyether (meth)acrylates, urethane (meth)acrylates, carbonate (meth)acrylates, epoxy (meth)acrylates, etc. Specific examples include alkyl acrylates such as 2-ethylhexyl acrylate and cyclohexyl acrylate; hydroxyalkyl acrylates such as 2-hydroxyethyl acrylate and 2-hydroxypropyl acrylate; mono- or diacrylates of alkylene oxide derivatives such as ethylene glycol, propylene glycol, diethylene glycol, and dipropylene glycol; acrylamides such as N,N-dimethylacrylamide, N-methylolacrylamide, and N,N-dimethylaminopropylacrylamide; aminoalkyl acrylates such as N,N-dimethylaminoethyl acrylate and N,N-dimethylaminopropyl acrylate; and various alkyl acrylates such as hexanediol, trimethylolpropane, pentaerythritol, ditrimethylolpropane, dipentaerythritol, and trishydroxyethyl isocyanurate. Examples of suitable photopolymerizable monomers include polyhydric acrylates derived from hydroxyl alcohols or their alkylene oxide adducts or ε-caprolactone adducts; polyhydric acrylates such as phenols (e.g., phenoxy acrylate, bisphenol A diacrylate) or their alkylene oxide adducts; acrylates derived from glycidyl ethers (e.g., glycerin diglycidyl ether, trimethylolpropane triglycidyl ether, triglycidyl isocyanurate); and acrylates and melamine acrylates obtained by directly or via diisocyanate urethane acrylate of polyols (e.g., polyether polyols, polycarbonate diols, hydroxyl-terminated polybutadienes, polyester polyols), and methacrylates corresponding to the above acrylates. These photopolymerizable monomers can also be used as reactive diluents. The photopolymerizable monomers may be used singly or in combination of two or more.

[0049] The content of the photocurable compound not containing a carboxyl group in the first resin layer is preferably 0.1 to 50 parts by mass, calculated as solid content, per 100 parts by mass of the carboxyl group-containing resin. By setting the content of the photocurable compound not containing a carboxyl group in the first resin layer to 0.1 parts by mass or more per 100 parts by mass of the carboxyl group-containing resin, good photocurability can be achieved, and pattern formation can be facilitated by alkaline development after irradiation with active energy rays. On the other hand, by setting the content of the photocurable compound not containing a carboxyl group in the first resin layer to 50 parts by mass or less per 100 parts by mass of the carboxyl group-containing resin, halation during exposure of the laminate structure of the present invention can be suppressed, resulting in good resolution.

[0050] (Thermosetting catalyst) The first resin layer may contain a thermosetting catalyst as needed. Examples of the thermosetting catalyst include imidazole derivatives such as imidazole, 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 4-phenylimidazole, 1-cyanoethyl-2-phenylimidazole, and 1-(2-cyanoethyl)-2-ethyl-4-methylimidazole; amine compounds such as dicyandiamide, benzyldimethylamine, 4-(dimethylamino)-N,N-dimethylbenzylamine, 4-methoxy-N,N-dimethylbenzylamine, and 4-methyl-N,N-dimethylbenzylamine; hydrazine compounds such as adipic acid dihydrazide and sebacic acid dihydrazide; and phosphorus compounds such as triphenylphosphine. Commercially available catalysts include, for example, 2MZ-A, 2MZ-OK, 2PHZ, 2P4BHZ, and 2P4MHZ (all trade names of imidazole-based compounds) manufactured by Shikoku Chemical Industry Co., Ltd., and U-CAT 3513N (trade name of a dimethylamine-based compound), DBU, DBN, and U-CAT SA 102 (all bicyclic amidine compounds and salts thereof) manufactured by San-Apro Co., Ltd. However, the catalyst is not particularly limited to these, and any catalyst that promotes the reaction of a heat curing catalyst for an epoxy resin or an oxetane compound, or at least one of an epoxy group and an oxetanyl group with a carboxyl group may be used, and they may be used alone or in combination of two or more. In addition, S-triazine derivatives such as guanamine, acetoguanamine, benzoguanamine, melamine, 2,4-diamino-6-methacryloyloxyethyl-S-triazine, 2-vinyl-2,4-diamino-S-triazine, 2-vinyl-4,6-diamino-S-triazine·isocyanuric acid adduct, and 2,4-diamino-6-methacryloyloxyethyl-S-triazine·isocyanuric acid adduct can also be used, and these compounds that also function as adhesion promoters are preferably used in combination with a heat curing catalyst.The heat curing catalyst may be used alone or in combination of two or more.

[0051] The content of the thermosetting catalyst in the first resin layer is preferably 0.1 to 20 parts by mass, more preferably 1 to 15 parts by mass, calculated as solid content, per 100 parts by mass of the carboxyl group-containing resin. By setting the content of the thermosetting catalyst in the first resin layer to 1 part by mass or more per 100 parts by mass of the carboxyl group-containing resin, the cured product of the first resin layer can be made to have excellent heat resistance. On the other hand, by setting the content of the thermosetting catalyst in the first resin layer to 15 parts by mass or less per 100 parts by mass of the carboxyl group-containing resin, the storage stability of the first resin layer can be made good.

[0052] (coloring agent) The first resin layer may contain a colorant, if necessary, such as a pigment, dye, or coloring matter, and may be any of commonly used and known colorants, such as red, blue, green, yellow, white, and black.

[0053] Specific examples of colorants include those assigned the following Color Index (CI; published by The Society of Dyers and Colourists) numbers.

[0054] Examples of red colorants include monoazo, disazo, azo lake, benzimidazolone, perylene, diketopyrrolopyrrole, condensed azo, anthraquinone, and quinacridone. Examples of blue colorants include phthalocyanine and anthraquinone, and examples of pigments include compounds classified as pigments. In addition to these, metal-substituted or unsubstituted phthalocyanine compounds can also be used. Examples of green colorants include phthalocyanine, anthraquinone, and perylene. In addition to these, metal-substituted or unsubstituted phthalocyanine compounds can also be used. Examples of yellow colorants include monoazo, disazo, condensed azo, benzimidazolone, isoindolinone, and anthraquinone. Examples of white colorants include rutile or anatase titanium oxide. Examples of black colorants include carbon black, graphite, iron oxide, titanium black, anthraquinone, cobalt oxide, copper oxide, manganese, antimony oxide, nickel oxide, perylene, aniline, molybdenum sulfide, bismuth sulfide, etc. In addition, purple, orange, brown, etc. colorants may be added to adjust the color tone.

[0055] From the viewpoint of improving the concealing properties of the cured product of the first resin layer, the content of the colorant in the first resin layer is preferably 0.18 to 0.50 mass %, more preferably 0.20 to 0.40 mass %, calculated as solid content, relative to the total mass of the first resin layer. By making the content of the colorant in the first resin layer 0.18 mass % or more relative to the total mass of the first resin layer, excellent circuit concealing properties can be achieved. On the other hand, by making the content of the colorant in the first resin layer 0.50 mass % or less relative to the total mass of the first resin layer, even better resolution can be achieved.

[0056] (organic solvent) The first resin layer may contain an organic solvent to the extent that the effects of the present invention are not impaired. 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. The organic solvent may be used alone or in combination of two or more. Generally, an organic solvent can be blended into the resin composition constituting the resin layer for the purpose of adjusting the viscosity when preparing the resin composition or when applying it to a substrate or film. In this case, when forming the resin layer, the organic solvent contained in the resin composition constituting the resin layer may remain in the resin layer, resulting in the organic solvent being contained in the resin layer. Therefore, in one embodiment, the organic solvent contained in the first resin layer and the second resin layer described below is contained in each resin layer as a residue of the organic solvent contained in the resin composition constituting each resin layer.

[0057] The organic solvent can be evaporated and dried using a hot air circulation drying oven, an IR oven, a hot plate, a convection oven, etc. (a method using an oven equipped with a heat source for air heating using steam, in which hot air in the dryer is brought into countercurrent contact, or a method in which hot air is blown onto the support from a nozzle).

[0058] The content of the organic solvent in the first resin layer is preferably changed appropriately depending on the components constituting the first resin layer, but can be, for example, 50 to 400 parts by mass, converted into solid content, per 100 parts by mass of the carboxyl group-containing resin.

[0059] (Other ingredients) The first resin layer may optionally contain components such as a photoinitiator aid, cyanate compound, elastomer, mercapto compound, urethane catalyst, thixotropy agent, adhesion promoter, block copolymer, chain transfer agent, polymerization inhibitor, copper inhibitor, antioxidant, rust inhibitor, thickener such as organic bentonite or montmorillonite, at least one of silicone-based, fluorine-based, or polymer-based defoaming agent and leveling agent, imidazole-based, thiazole-based, or triazole-based silane coupling agent, phosphinate, phosphate ester derivative, phosphazene compound, or other phosphorus compound, etc. These may be flame retardants such as those known in the field of electronic materials.

[0060] <Second resin layer> The laminate structure of the present invention includes a second resin layer containing a carboxyl group-containing resin, a photopolymerization initiator, a thermosetting component, a perovskite compound, silica, and a photocurable compound that does not contain a carboxyl group. The second resin layer is composed of a dried coating of a resin composition and contributes to the high dielectric constant of the cured product of the laminate structure of the present invention. When a printed wiring board is manufactured using the laminate structure of the present invention, the second resin layer is typically positioned so as to be in contact with the substrate that constitutes the printed wiring board. Each component of the second resin layer is described in detail below.

[0061] The carboxyl group-containing resin, photopolymerization initiator, thermosetting component, and carboxyl group-free photocurable compound to be incorporated into the second resin layer can be the same as those described above for the first resin layer. The second resin layer can also contain the same thermosetting catalyst, colorant, organic solvent, and other components as those described above for the first resin layer. The content of each component in the second resin layer other than the carboxyl group-containing resin and colorant can be the same as those described above for the first resin layer. The content of the carboxyl group-containing resin in the second resin layer is preferably 5 to 30% by mass, more preferably 5 to 20% by mass, calculated as solids, relative to the total mass of the second resin layer. The content of the colorant in the second resin layer is preferably 0.1 to 20% by mass, calculated as solids, relative to the total mass of the second resin layer.

[0062] (Second filler) The second resin layer contains a filler (also referred to herein as "second filler"). The second filler includes at least a perovskite compound and silica. By incorporating a large amount of a perovskite compound and silica as the second filler into the second resin layer, the dielectric constant of the cured product formed by curing the second resin layer can be increased. Furthermore, the deterioration of deep curability of the cured product, which occurs when a large amount of filler is incorporated into the second resin layer, can be suppressed, and a decrease in resolution can be suppressed. Thus, the reason why an increase in the dielectric constant of the cured product of the second resin layer and a suppression of a decrease in resolution can both be achieved when a large amount of a perovskite compound and silica are incorporated into the second resin layer as the second filler is unclear, but it is inferred as follows. That is, by incorporating a large amount of a perovskite compound with a high relative dielectric constant as the second filler into the second resin layer, the dielectric constant of the cured product formed by the second resin layer can be increased. On the other hand, if a large amount of silica, which has low transparency (i.e., high absorption or a high refractive index), is incorporated into the second resin layer as the second filler, it is believed that the deep curing properties of the cured product will be impaired due to the blocking or diffusion of light during exposure caused by such a large amount of filler. Furthermore, perovskite compounds have a particularly high refractive index, which tends to impair the deep curing properties of the cured product. Therefore, by incorporating a perovskite compound in combination with silica, which has a relatively low refractive index, it is believed that the blocking or diffusion of light during exposure can be suppressed, thereby preventing the deterioration of deep curing properties of the cured product caused by the incorporation of a large amount of filler, and thus reducing the decrease in resolution.

[0063] The perovskite compound contained in the second filler is represented by the general formula ABO3 (A and B are divalent and tetravalent metal ions, respectively, and O is an oxygen ion). There are no particular limitations on the compound as long as it has the same crystal structure as perovskite (perovskite), and a compound with any elemental composition can be used. Examples of perovskite compounds include barium titanate, calcium titanate, strontium titanate, barium zirconate, calcium zirconate, strontium zirconate, and composite oxides containing these as main components. One type of perovskite compound may be used alone, or two or more types may be used in combination. Preferred perovskite compounds are barium titanate, calcium titanate, and strontium titanate. Commercially available perovskite compounds include the BT series, CT series, ST series, CZ series, SZ series, and CZ series manufactured by Sakai Chemical Industry Co., Ltd.

[0064] The perovskite compound is preferably surface-treated. The surface treatment of the perovskite compound is not particularly limited as long as it provides a reactive functional group on the surface of the perovskite compound, and conventionally known filler surface treatments can be used. Examples of reactive functional groups provided on the surface of the perovskite compound include methacrylic groups, carboxyl groups, hydroxyl groups, sulfonic acid groups, amino groups, epoxy groups, vinyl groups, mercapto groups, and acid anhydrides. The surface-treated perovskite compound may have one type of reactive functional group or two or more types of reactive functional groups. When two or more surface-treated perovskite compounds are used, they may have the same reactive functional group or different reactive functional groups. The surface-treated perovskite compound is preferably a perovskite compound having a methacrylic group on its surface. By surface-treating the perovskite compound, it is possible to particularly suppress a decrease in resolution and improve the mechanical properties and handleability of the resin composition and its cured product.

[0065] A conventional method can be used to obtain a surface-treated perovskite compound, i.e., to provide a reactive functional group on the surface of a perovskite compound. For example, a method can be used in which a coupling agent having a reactive functional group (e.g., a silane compound (a so-called silane coupling agent), a titanate coupling agent (a titanium coupling agent), etc.) is bonded to the perovskite compound (i.e., the perovskite compound is bonded to the reactive functional group via the coupling agent). In this specification, the term "bonding" between a coupling agent and a perovskite compound refers not only to bonding involving a chemical reaction between the coupling agent and the perovskite compound (chemisorption), but also to bonding without such a chemical reaction (physisorption).

[0066] Examples of coupling agents include silane-based, titanate-based, aluminate-based, and zircoaluminate-based agents. Of these, silane-based or titanate-based coupling agents are preferred, and silane-based coupling agents are particularly preferred. Examples of silane-based coupling agents include vinyltrimethoxysilane, vinyltriethoxysilane, N-(2-aminomethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-anilinopropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, and 3-mercaptopropyltrimethoxysilane. Coupling agents may be used alone or in combination of two or more.

[0067] When the surface-treated perovskite compound is obtained by bonding a coupling agent having a reactive functional group with a perovskite compound, conventionally known methods can be used. Specifically, the method includes dispersing a powdered perovskite compound in a solvent containing a coupling agent having a reactive functional group (with the solvent removed as necessary) and contacting the two. Alternatively, the method includes directly adding the powdered perovskite compound to the coupling agent having a reactive functional group, mixing, and contacting the two. If necessary, the method may include a heating step after contacting the coupling agent having a reactive functional group with the powdered perovskite compound. The amount of the coupling agent having a reactive functional group to be contacted with the powdered perovskite compound (the amount of the coupling agent to be treated) can be appropriately determined depending on the method for bonding the coupling agent having a reactive functional group with the perovskite compound, the type of reactive functional group, the type of coupling agent, and the like.

[0068] In one embodiment, the second filler contains a perovskite compound having a refractive index of 2.2 to 2.8. Generally, the refractive index is proportional to the square root of the dielectric constant, so the higher the refractive index, the higher the dielectric constant. Therefore, by including a perovskite compound having a relatively high refractive index of 2.2 to 2.8 in the second filler, the dielectric constant of the cured product can be made favorable.

[0069] The particle size of the perovskite compound is not particularly limited and can be set appropriately, for example, to 0.3 to 1.0 μm. By setting the average particle size of the perovskite compound within this range, the decrease in light transmittance during exposure can be suppressed, improving the deep curability of the cured product and improving dispersibility in the second resin layer. In this specification, the average particle size of the filler refers to the average particle size before being incorporated into the second resin layer, and is the D50 value measured by laser diffraction. The device used to measure the average particle size (D50) by laser diffraction is the Microtrac MT3300EXII manufactured by Microtrac-Bell Corporation.

[0070] The content of the perovskite compound in the second resin layer is 25 to 55% by volume, preferably 40 to 55% by volume, and more preferably 40 to 50% by volume, based on the total volume of the second resin layer, calculated as solid content. A perovskite compound content of 25% by volume or more can improve the dielectric constant of the cured product. On the other hand, a perovskite compound content of 55% by volume or less can improve resolution.

[0071] The silica contained in the second resin layer may be any of amorphous silica, non-crystalline silica, crystalline silica, fused silica, spherical silica, etc. One type of silica may be used alone, or two or more types may be used in combination. Commercially available silica products include SC2500-SMJ manufactured by Admatechs Co., Ltd.

[0072] The particle size of the silica is not particularly limited and can be set appropriately, for example, to 0.4 to 0.65 μm.

[0073] The silica may or may not be surface-treated. The type and method of surface treatment of the silica are not particularly limited, and may be the same as the surface treatment of the perovskite compound described above, for example.

[0074] The silica content in the second resin layer is preferably 0.6 to 6.0 volume %, more preferably 0.7 to 5.0 volume %, calculated as solid content, relative to the total volume of the second resin layer. A silica content of 0.6 volume % or more can improve the deep curability of the cured product. On the other hand, a silica content of 6.0 volume % or less can ensure a sufficient dielectric constant due to the perovskite compound, thereby improving the dielectric constant of the cured product.

[0075] The second resin layer may further contain other fillers in addition to the perovskite compound and silica described above. Examples of other fillers that can be used include known inorganic or organic fillers, such as hydrotalcite, talc, and metal oxides such as titanium oxide for achieving a white appearance and flame retardancy, and metal hydroxides such as aluminum hydroxide.

[0076] [Method of manufacturing laminated structure] The laminate structure of the present invention comprises a first film, a first resin layer formed on the first film, and a second resin layer formed on the first resin layer. The term "first film" as used herein refers to a film that is adhered to at least the first resin layer when a base material such as a substrate and the second resin layer formed on the laminate structure are laminated together by heating or other means to form an integrated structure. The first film may be peeled from the first resin layer in a post-lamination process. In particular, the present invention can suppress light scattering when the laminate structure is exposed to light. Therefore, even if the first film is not peeled off during exposure, halation caused by light scattering within the first film can be suppressed.

[0077] In the laminate structure of the present invention, the resin composition constituting the first resin layer is diluted with the organic solvent to adjust the viscosity to an appropriate level and applied to a uniform thickness on the first film 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 resin composition constituting the second resin layer is then similarly applied to a uniform thickness on the first resin layer, and typically dried at a temperature of 50 to 130°C for 1 to 30 minutes to obtain a film. There are no particular limitations on the coating thickness, but the thickness after drying is generally selected appropriately from the range of 1 to 150 μm, preferably 10 to 60 μm.

[0078] The first film can be any known film without particular limitation, and examples of suitable films include polyester films such as polyethylene terephthalate and polyethylene naphthalate, and films made of thermoplastic resins such as polyimide films, polyamideimide films, polypropylene films, and polystyrene films. Among these, polyester films are preferred from the viewpoints of heat resistance, mechanical strength, ease of handling, etc. A laminate of these films can also be used as the first film.

[0079] Moreover, from the viewpoint of improving mechanical strength, the thermoplastic resin film as described above is preferably a film that has been oriented in a uniaxial or biaxial direction.

[0080] The thickness of the first film is not particularly limited, but can be, for example, 10 μm to 150 μm.

[0081] After forming a first resin layer on a first film and then forming a second resin layer on the first resin layer, it is preferable to further laminate a peelable second film on the surface of the second resin layer for the purpose of preventing dust from adhering to the surface of the second resin layer. The second film refers to a film that is peeled from the second resin layer before lamination when laminating a base material such as a substrate and the second resin layer formed on the laminate structure by heating or the like so that they are in contact with each other to form an integrated structure. Examples of peelable second films that can be used include polyethylene film, polytetrafluoroethylene film, polypropylene film, and surface-treated paper. The second film may be any film that, when peeled, has a weaker adhesive strength between the second resin layer and the second film and between the first resin layer and the second resin layer than the adhesive strength between the first resin layer and the first film.

[0082] The thickness of the second film is not particularly limited, but can be, for example, 10 μm to 150 μm.

[0083] [Cured product] The laminate structure of the present invention can be cured to obtain a cured product (hereinafter also referred to as the "cured product of the present invention") by curing the resin layer. The cured product of the present invention has high dielectric properties and good resolution. Therefore, the cured product of the present invention is suitable for use in forming an insulating layer in an FC-BGA substrate, such as that used in a capacitive fingerprint detection device, which requires a particularly high dielectric constant.

[0084] [Printed wiring board] The printed wiring board of the present invention includes the cured product of the present invention. As a method for producing the printed wiring board of the present invention, for example, the laminated structure of the present invention is attached to a substrate using a laminator or the like so that the second resin layer contacts the substrate, thereby forming a resin layer on the substrate.

[0085] The substrate for printed wiring boards includes printed wiring boards and flexible printed wiring boards with circuits already formed using copper or other materials, 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, polyethylene terephthalate film, polyethylene naphthalate (PEN) film, glass substrates, ceramic substrates, and wafer plates.

[0086] The lamination of the laminated structure onto the substrate is preferably carried out under pressure and heat using a vacuum laminator or the like. By using such a vacuum laminator, when a circuit-formed substrate is used, even if the circuit substrate surface is uneven, the laminated structure adheres tightly to the circuit substrate, preventing the inclusion of air bubbles and improving the filling of recesses in the substrate surface. The pressure condition is preferably about 0.1 to 2.0 MPa, and the heating condition is preferably 40 to 120°C.

[0087] The volatilization drying carried out after laminating the laminated structure of the present invention can be carried out using a hot air circulation drying oven, an IR oven, a hot plate, a convection oven, etc. (a method in which hot air in the dryer is brought into countercurrent contact using a heat source of an air heating method using steam, or a method in which hot air is blown onto the support from a nozzle).

[0088] After forming a resin layer on a substrate, the resin layer is selectively exposed to active energy rays through a photomask having a predetermined pattern formed thereon, and the unexposed areas are developed with a dilute alkaline aqueous solution (e.g., a 0.3 to 3 mass % aqueous solution of sodium carbonate) to form a pattern of a cured product. In this case, the first film may be peeled off from the laminate structure after exposure and development may be carried out to form a patterned cured product on the substrate, or the first film may be peeled off from the laminate structure before exposure and the exposed resin layer may be exposed and developed to form a patterned cured product on the substrate.

[0089] The exposure device used for actinic 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:

[0090] 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.

[0091] When curing the resin layer of the laminated structure of the present invention, if necessary, after the exposure and development by irradiation with active energy rays as described above, ultraviolet light may be irradiated to further promote curing (post-UV), or heat may be applied to promote thermal curing (post-cure). By performing post-UV and post-cure, the properties of the cured resin layer, such as heat resistance, chemical resistance, moisture absorption resistance, adhesion, and electrical properties, can be further improved. Post-UV is performed, for example, by using a UV conveyor or the like to irradiate the resin layer with 1000 mJ / cm. 2 The post-cure can be carried out by irradiating the film with UV light with an integrated exposure amount of 150° C. for 60 minutes using the various dryers mentioned above.

[0092] The laminate structures of the present invention are suitable for use in the manufacture of electronic components such as printed wiring boards, and more preferably for forming permanent coatings (cured products). The laminate structures of the present invention can form cured products with high dielectric constants, which can contribute to the miniaturization and thinning of antennas, particularly in electronic devices. When forming cured products with such high dielectric constants, the laminate structures of the present invention are used to form the cured products by the methods described above. When the resin layer formed by the laminate structures of the present invention is insulating, it is preferably used to form solder resists, coverlays, or interlayer insulating layers. The resin layers of the present invention can also be used to form solder dams. [Example]

[0093] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. In the examples, "parts" and "%" are all by mass unless otherwise specified.

[0094] [Fabrication of laminated structure] (Synthesis example of carboxyl group-containing resin) Before producing the laminated structure, a carboxyl group-containing resin used in this example was prepared according to the procedure described below. First, 325.0 parts by mass of dipropylene glycol monomethyl ether was placed as a solvent in a flask equipped with a thermometer, a stirrer, a dropping funnel, and a reflux condenser, and the mixture was heated to 110°C. A mixture of 174.0 parts by mass of methacrylic acid, 174.0 parts by mass of ε-caprolactone-modified methacrylic acid (average molecular weight 314), 77.0 parts by mass of methyl methacrylate, 222.0 parts by mass of dipropylene glycol monomethyl ether, and 12.0 parts by mass of t-butylperoxy 2-ethylhexanoate (manufactured by NOF Corporation, Perbutyl (registered trademark) O) as a polymerization catalyst was added dropwise over 3 hours, and the mixture was stirred at 110°C for a further 3 hours to deactivate the polymerization catalyst, thereby obtaining a resin solution. The resulting resin solution was cooled, and then 289.0 parts by mass of Cyclomer M100 (3,4-epoxycyclohexylmethyl methacrylate) manufactured by Daicel Corporation, 3.0 parts by mass of triphenylphosphine, and 1.3 parts by mass of hydroquinone monomethyl ether were added and stirred at 100°C to carry out a ring-opening addition reaction of the epoxy groups, yielding a carboxyl group-containing resin. The resulting carboxyl group-containing resin had a solids content of 45.5% by mass and an acid value of the solids of 79.8 mgKOH / g.

[0095] (Synthesis example of perovskite compound 1) Before fabricating the laminated structure, the surface-treated perovskite compound used in this example was prepared according to the procedure described below. First, a mixture of 2000 parts by mass of barium titanate manufactured by Sakai Chemical Industry Co., Ltd., 100 parts of the silane coupling agent KBM503 (methacrylic silane) manufactured by Shin-Etsu Chemical Co., Ltd., and 200 parts of propylene glycol monomethyl ether acetate (PMA) manufactured by Daicel Chemical Industries, Ltd. was prepared and stirred at room temperature for 30 minutes using a mixer to obtain a perovskite compound with methacrylic groups attached to its surface. The refractive index of the perovskite compound, barium titanate, is 2.41.

[0096] (Synthesis example of perovskite compound 2) First, a mixture of 2,000 parts by mass of calcium titanate manufactured by Denka Co., Ltd., 100 parts of a silane coupling agent KBM503 (methacrylic silane) manufactured by Shin-Etsu Chemical Co., Ltd., and 200 parts of propylene glycol monomethyl ether acetate (PMA) manufactured by Daicel Chemical Industries, Ltd. was prepared and stirred at room temperature for 30 minutes using a mixer to obtain a perovskite-type compound with methacrylic groups attached to its surface. The refractive index of the perovskite-type compound, calcium titanate, is 2.38.

[0097] The components shown in Table 1 below were mixed in the amounts shown in the table, premixed in a mixer, and then kneaded using a three-roll mill to prepare resin compositions constituting the first and second resin layers. Details of each component in Table 1 are as follows. *1: Carboxyl group-containing resin: A carboxyl group-containing resin obtained by the synthesis example of the carboxyl group-containing resin described above. *2: Photopolymerization initiator: Irgacure OXE04 manufactured by BASF Japan Ltd. *3: Thermosetting component: jER (registered trademark) 828 manufactured by Mitsubishi Chemical Corporation *4: Filler 1: YA050C-HHL (refractive index: 1.46) manufactured by Admatechs Co., Ltd. *5: Filler 2: Barium titanate (refractive index: 2.41) manufactured by Sakai Chemical Industry Co., Ltd. *6: Organic solvent: Jukisol CA manufactured by Dow Chemical Japan Co., Ltd. *7: Perovskite compound 1: A perovskite compound (refractive index: 2.41) obtained by the synthesis example of perovskite compound 1 described above. *8: Perovskite compound 2: Perovskite compound obtained by the synthesis example of perovskite compound 2 described above (refractive index: 2.38) *9: Silica: SC2500-SMJ manufactured by Admatechs Co., Ltd. *10: Photocurable compound that does not contain a carboxyl group: Neomer DA-600 manufactured by Sanyo Chemical Industries, Ltd.

[0098] [Table 1]

[0099] Using each resin composition obtained according to the above-mentioned procedure, a laminate structure (dry film) was produced according to the following procedure. First, using a bar coater, each resin composition constituting the first resin layer was applied to one side of a first film (polyethylene terephthalate (PET) film) so that the film thickness after drying was as shown in Table 2 below, and the applied film was dried at 100°C for 5 to 10 minutes in a hot air circulation drying oven. Next, using a bar coater, each resin composition constituting the second resin layer was applied to the first resin layer. Next, the applied film was dried at 100°C for 5 to 10 minutes in a hot air circulation drying oven to form first and second resin layers on the first film. Next, a second film (polypropylene (PP) film) was laminated onto the surface of the second resin layer to obtain a laminate structure.

[0100] [Table 2]

[0101] [Resolution evaluation] A double-sided copper-clad laminate (copper foil thickness 35 μm, substrate thickness 1.6 mm, substrate size 150 mm × 95 mm) manufactured by Resonac Co., Ltd. was etched at a rate of 1 μm / m using MEC Etch Bond CZ-8101 manufactured by MEC Co., Ltd. 2 The roughened substrates were subjected to CZ treatment (roughening treatment) using a vacuum laminator CVP-300 manufactured by Nikko Materials Co., Ltd. The second film was peeled from each laminate structure obtained according to the procedure described above, and then the second resin layer was laminated onto the roughened surface of the roughened substrate so that it was in contact with the roughened surface. The laminate structure was then laminated onto the roughened substrate. The lamination was performed in a chamber at 100°C under conditions of a vacuum pressure of 3 hPa, a vacuum time of 30 seconds, a pressure time of 30 seconds, and a press pressure of 0.4 MPa.

[0102] Next, an exposure device EXP-2960 (light source: short arc lamp, parallel light exposure device) manufactured by Oak Manufacturing Co., Ltd. was used, and the exposure was performed at 200 mJ / cm 2 After the exposure, the first film was peeled off from the laminated structure, and the laminated structure was developed for 60 seconds using a 1 wt % aqueous solution of sodium carbonate at 30°C and a spray pressure of 0.2 MPa. The developed film was then exposed to a UV conveyor oven at a dose of 1000 mJ / cm. 2 The sample substrates were then heated at 150° C. for 60 minutes in a hot air circulation drying oven to fully cure the cured product on each sample substrate.

[0103] The opening diameter of the micropore pattern of the cured product on each sample substrate was measured, and the resolution after thermal curing was evaluated according to the following evaluation criteria. The evaluation results are shown in Table 2. ⊚: The opening diameter of 100 μm was maintained, and the amount of undercut on one side was less than 10 μm. ◯: The opening diameter of 100 μm was maintained, but the amount of undercut on one side was 10 μm or more. ×: The opening diameter of 100 μm was not maintained, and the opening diameter was significantly reduced.

[0104] [Measurement of dielectric constant] Using a vacuum laminator CVP-300 manufactured by Nikko Materials Co., Ltd., the second film was peeled from each laminate structure obtained according to the procedure described above, and then the laminate structure was laminated on the surface of an 18 μm-thick electrolytic copper foil manufactured by Furukawa Electric Co., Ltd. so that the second resin layer was in contact with the surface. Note that lamination was performed in a chamber at 100°C under conditions of a vacuum pressure of 3 hPa, a vacuum time of 30 seconds, a pressure time of 30 seconds, and a press pressure of 0.4 MPa.

[0105] Next, an exposure device EXP-2960 (light source: short arc lamp, parallel light exposure device) manufactured by Oak Manufacturing Co., Ltd. was used, and the exposure was performed at 200 mJ / cm 2 After the entire surface of the resin layer was exposed to an integrated exposure amount of 1000 ppm, the first film was peeled off from the laminated structure.

[0106] A resin layer (25 μm thick) of the laminated structure was further laminated on the exposed resin layer (25 μm thick) to form a resin layer with a thickness of 50 μm on the electrolytic copper foil. Next, the first film was peeled off, and the resin layer was exposed to 200 mJ / cm using an exposure device EXP-2960 (light source: short arc lamp, parallel light exposure device) manufactured by Oak Manufacturing Co., Ltd. 2 The entire resin layer was exposed to an integrated exposure dose of 1000 mJ / cm2 to obtain an electrolytic copper foil having a cured product (solder resist layer). The lamination was performed in a chamber at 100°C under the conditions of a vacuum pressure of 3 hPa, a vacuum time of 30 seconds, a pressure time of 30 seconds, and a press pressure of 0.4 MPa. The resin layer (thickness 50 μm) laminated on this electrolytic copper foil was irradiated with 1000 mJ / cm2 using a UV conveyor furnace. 2 Then, the foil was heated at 150° C. for 60 minutes to fully cure the cured product on the surface of each electrodeposited copper foil.

[0107] Next, the copper foil was etched away from each of the electrodeposited copper foils provided with the cured product using an etching solution having a composition of 340 g / L of cupric chloride and a free hydrochloric acid concentration of 51.3 g / L, and the foil was thoroughly washed with water and dried to obtain sample electrodeposited copper foils provided with the cured product each having a thickness of 50 μm.

[0108] The dielectric constant of each sample electrodeposited copper foil was measured at 10 GHz by the SPDR method using an SPDR dielectric resonator and network analyzer Agilent E4991A (RF impedance / material analyzer) manufactured by Agilent Technologies, Inc., and evaluated based on the measured values ​​according to the following evaluation criteria. The evaluation results are shown in Table 2. ◎: The dielectric constant was 15 or more. ◯: The dielectric constant was 10 or more and less than 15. ×: The dielectric constant was less than 10.

[0109] The evaluation results shown in Table 2 show that the solder resist layers formed using the laminate structures of Examples 1 to 7 have both good resolution and high dielectric constant, while the solder resist layers formed using the laminate structures of Comparative Examples 1 to 5 do not have both good resolution and high dielectric constant.

Claims

1. A laminated structure including a first film, a first resin layer, and a second resin layer, the first film, the first resin layer, and the second resin layer are laminated in this order; the first resin layer contains a carboxyl group-containing resin, a photopolymerization initiator, and a thermosetting component; the second resin layer contains a carboxyl group-containing resin, a photopolymerization initiator, a thermosetting component, a perovskite compound, silica, and a photosetting compound that does not contain a carboxyl group; the content of the filler in the first resin layer is 0 to 10% by volume in terms of solid content; the content of the perovskite compound in the second resin layer is 25 to 55% by volume in terms of solid content; The laminate structure, wherein when the content of the filler in the first resin layer exceeds 0% by volume, the refractive index of the filler is less than 2.

2.

2. 2. The layered structure according to claim 1, wherein the perovskite compound includes a perovskite compound having a refractive index of 2.2 to 2.

8.

3. 2. The laminate structure according to claim 1, wherein the content of the perovskite compound in the second resin layer is 30 to 55% by volume in terms of solid content.

4. 2. The laminate structure according to claim 1, wherein the perovskite compound comprises at least one compound selected from the group consisting of barium titanate, calcium titanate, and strontium titanate.

5. 2. The laminate structure according to claim 1, wherein the perovskite compound is surface-treated with at least one agent selected from the group consisting of a silane coupling agent and a titanate coupling agent.

6. A cured product obtained by curing the first resin layer and the second resin layer of the laminate structure according to any one of claims 1 to 5.

7. A printed wiring board comprising the cured product according to claim 6.

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