Cured product of resin composition, wiring board, and semiconductor package

Abstract

One aspect of the present invention is a cured product of a resin composition. The resin composition contains a filler. The filler has a 50%-particle size D50 of at most 2100 nm in a volume-based cumulative particle size distribution. The contained amount of the filler is less than 35 mass% with respect to the resin composition. The cured product has a relative dielectric constant of less than 2.6 at 10 GHz. The cured product has a surface roughness Ra of less than 100 nm.

Description

Cured product of resin composition, wiring board, and semiconductor package

[0001] The present invention relates to a cured product of a resin composition, a wiring board, and a semiconductor package.

[0002] As the amount of information processed in various electronic devices increases, packaging technologies such as higher integration of semiconductor devices, higher wiring density, and multi-layering have advanced. Furthermore, wiring boards used in various electronic devices are provided with insulating layers, for example, in rewiring layers such as build-up layers for multi-layering. Examples of insulating layers provided in such wiring boards include the insulating layer in the adhesive film described in Patent Document 1 and the hardened layer in the printed wiring board described in Patent Document 2.

[0003] Patent Document 1 describes an adhesive film including a support and a resin composition layer, in which the arithmetic mean roughness Ra of the surface of the support that contacts the resin composition layer is １ Patent Document 1 describes an adhesive film in which the dielectric loss tangent of the insulating layer formed by thermal curing of the resin composition layer is 200 nm or more, the dielectric loss tangent of the insulating layer is 0.005 or less, and the support is a film made of a plastic material or a film made of a plastic material with a release layer. Patent Document 1 discloses that the adhesive film can improve the adhesion of the dry film despite the low dielectric loss tangent.

[0004] Patent Document 2 describes a printed wiring board having a cured layer formed by thermally curing a resin composition containing a thermosetting resin, the cured layer having a first opening with an opening diameter of 50 μm or more on one side of the cured layer, a first via hole formed from the first opening and penetrating the cured layer, and a second via hole formed from the second opening with an opening diameter of 32 μm or less on the same side and penetrating the cured layer from the second opening, the cured layer having a thickness of 25 μm or less, and the cured layer having an elastic modulus at 25°C of 5 GPa or more and 15 GPa or less. Patent Document 2 discloses that it is possible to efficiently and simultaneously form large via holes by sandblasting and small via holes by laser processing while suppressing cracking and warping. It also discloses that by manufacturing a printed wiring board having via holes with different opening diameters in the same cured layer using a material with relatively high insulation reliability, it is possible to design more complex and precise semiconductor devices than ever before.

[0005] Wiring boards used in various electronic devices, such as substrates for servers in communication infrastructure, are required to be high-frequency compatible. For this reason, wiring boards used in various electronic devices are required to be able to increase signal transmission speeds. Therefore, the wiring boards are required to be able to reduce signal transmission loss. Specifically, the wiring boards are required to have an insulating layer that can reduce signal transmission loss more than conventional wiring boards, such as the wiring boards having an insulating layer in an adhesive film described in Patent Document 1 and the printed wiring board described in Patent Document 2. Furthermore, the insulating layer provided on the wiring board is, for example, a layer formed after processing a cured resin composition for wiring. Therefore, when plasma processing is performed for wiring, it is believed that signal transmission loss can be reduced if the cured resin composition used for the insulating layer has low dielectric properties such as a dielectric constant and low surface roughness after plasma processing.

[0006] JP 2020-74444 A JP 2022-70723 A

[0007] The present invention has been made in view of the above circumstances, and aims to provide a cured product of a resin composition that has low dielectric properties such as a dielectric constant and low surface roughness after plasma treatment. Another aim of the present invention is to provide a wiring board and a semiconductor package obtained using the cured product of the resin composition.

[0008] One aspect of the present invention is a cured product of a resin composition, the resin composition including a filler, the filler having a 50% particle size D50 in a volume-based cumulative particle size distribution of 2100 nm or less, the content of the filler being less than 35 mass% of the resin composition, the cured product having a relative dielectric constant at 10 GHz of less than 2.6, and the cured product having a surface roughness Ra of less than 100 nm.

[0009] These and other objects, features, and advantages of the present invention will become apparent from the following detailed description and the accompanying drawings.

[0010] Fig. 1 is a schematic diagram illustrating an example of a method for manufacturing a wiring board using a cured product according to an embodiment of the present invention. Fig. 2 is a schematic diagram illustrating another example of a method for manufacturing a wiring board using a cured product according to an embodiment of the present invention.

[0011] Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to these.

[0012] As a result of extensive investigations, the present inventors have found that the above object can be achieved by the present invention described below.

[0013] [Cured Product of Resin Composition] The cured product of the resin composition according to the embodiment of the present invention is a cured product obtained by curing a resin composition containing a filler. The filler has a 50% particle diameter D50 in a volume-based cumulative particle size distribution of 2100 nm or less, and its content is less than 35 mass% relative to the resin composition. The cured product also has a relative dielectric constant of less than 2.6 at 10 GHz and a surface roughness Ra of less than 100 nm. Such a cured product has low dielectric properties such as a relative dielectric constant and a low surface roughness after plasma treatment. Specifically, even after plasma treatment of the cured product to form a conductor wiring pattern or the like on this low dielectric loss tangent cured product, the surface roughness Ra remains low, for example, less than 100 nm. Because of this low relative dielectric constant of less than 2.6 at 10 GHz and a low surface roughness Ra of less than 100 nm after plasma treatment, signal transmission loss in the conductor wiring (conductor circuit) formed on the cured product can be reduced.

[0014] (Filler) The filler has a 50% particle diameter D50 in the volume-based cumulative particle diameter distribution of 2100 nm or less, preferably 100 to 700 nm, more preferably 100 to 600 nm, and even more preferably 100 to 500 nm. By using a filler that has such a particle diameter distribution as the filler, a cured product can be obtained that maintains a low surface roughness Ra after plasma treatment. This is thought to be due to the following. The filler contained in the resin composition is thought to be a filler that contains a small amount of filler with an excessively large particle diameter, such that the 50% particle diameter D50 is 2100 nm or less. Therefore, by curing a resin composition containing a filler that has such a particle diameter distribution, a cured product can be obtained that maintains a low surface roughness Ra after plasma treatment.

[0015] The filler is not particularly limited as long as the 99% particle diameter D99 in the volume-based cumulative particle diameter distribution is 2500 nm or less. The 99% particle diameter D99 is 2500 nm or less, preferably 700 to 1500 nm, and more preferably 700 to 1000 nm. By using a filler with such a particle diameter distribution as the filler, a cured product that maintains a low surface roughness Ra after plasma treatment can be more suitably obtained. This is thought to be due to the following. First, the 99% particle diameter D99 is thought to be the maximum particle diameter of particles other than the large particles that are inevitably contained. From this, it is thought that the filler contained in the resin composition is a filler with a low content of fillers with excessively large particle diameters, such that the 99% particle diameter D99 is 2500 μm or less. Therefore, it is thought that by curing a resin composition containing a filler with such a particle diameter distribution, a cured product that maintains a low surface roughness Ra after plasma treatment can be obtained.

[0016] The filler preferably has a 90% particle size D90 in the volume-based cumulative particle size distribution of 700 to 2300 nm, more preferably 700 to 1500 nm, and even more preferably 700 to 800 nm. By using a filler that has such a particle size distribution, a cured product can be obtained that can better maintain a low surface roughness Ra after plasma treatment.

[0017] The volume-based cumulative particle size distribution can be measured by known methods such as dynamic light scattering, centrifugal sedimentation, and laser diffraction scattering. The 50% particle size D50 is the particle size that is 50% from the smallest side in the volume-based cumulative particle size distribution. That is, D50 is the cumulative 50% particle size measured by laser diffraction scattering particle size distribution measurement, and is called the median size. The 99% particle size D99 is the particle size that is 99% from the smallest side in the volume-based cumulative particle size distribution. The 90% particle size D90 is the particle size that is 90% from the smallest side in the volume-based cumulative particle size distribution.

[0018] The filler may be, but is not limited to, organic or inorganic particles. Examples of the organic particles include, but are not limited to, acrylic particles, acrylonitrile particles, silicone particles, polycarbonate particles, polyolefin particles, polyester particles, polystyrene particles, melamine resin particles, and polyamide particles. Among these, acrylic particles, polystyrene particles, and polyolefin particles are preferred. Examples of the inorganic particles include, but are not limited to, silica particles, titanium oxide particles, aluminum oxide particles, tin oxide particles, indium oxide particles, zinc oxide particles, zirconium oxide particles, magnesium oxide particles, calcium carbonate particles, calcium carbonate particles, aluminum hydroxide particles, barium sulfate particles, and glass beads. The filler may also be hollow particles, specifically, for example, hollow organic particles such as hollow polystyrene particles, and hollow inorganic particles. Among these, the filler is preferably polystyrene particles, hollow polystyrene particles, inorganic particles, hollow inorganic particles, etc., and more preferably polystyrene particles, hollow polystyrene particles, silica particles, hollow silica particles, etc. The filler may be used alone or in combination of two or more thereof.

[0019] The resin composition contains the filler as described above so that its content is less than 35 mass % relative to the resin composition, and further so that the relative dielectric constant at 10 GHz of the cured product of the resin composition is less than 2.6.

[0020] The content of the filler relative to the resin composition is less than 35% by mass, preferably 30% by mass or less, and more preferably 25% by mass or less. While a lower filler content is preferable, in order to use the cured resin composition as an insulating layer on a wiring board, the filler content is preferably 5% by mass or more, and more preferably 7% by mass or more. Therefore, the filler content is preferably 5% by mass or more but less than 35% by mass, more preferably 5 to 30% by mass, and even more preferably 7 to 25% by mass. If the filler content is too high, the dielectric constant of the resin composition tends to be too high, and it may be impossible to achieve a dielectric constant of less than 2.6 at 10 GHz for the cured resin composition.

[0021] (Elastomer) The resin composition is not particularly limited as long as it is a resin composition containing the filler. Preferably, the resin composition further contains an elastomer.

[0022] The elastomer is not particularly limited, and examples thereof include elastomers contained in resin compositions used to form insulating layers provided in metal-clad laminates, wiring boards, etc. The resin compositions used to form insulating layers provided in metal-clad laminates, wiring boards, etc. may be resin compositions used to form resin layers provided in resin-coated films, resin-coated metal foils, etc., or may be resin compositions contained in prepregs. Examples of the elastomer include styrene-based polymers, etc.

[0023] The styrene-based polymer may be, for example, a polymer obtained by polymerizing a monomer containing a styrene-based monomer, and may be a styrene-based copolymer. Examples of the styrene-based copolymer include copolymers obtained by copolymerizing one or more of the styrene-based monomers with one or more other monomers copolymerizable with the styrene-based monomer. The styrene-based copolymer may be a random copolymer or a block copolymer, as long as it has a structure derived from the styrene-based monomer in its molecule. Examples of the block copolymer include a binary copolymer of the structure (repeating unit) derived from the styrene-based monomer and the other copolymerizable monomer (repeating unit), a terpolymer of the structure (repeating unit) derived from the styrene-based monomer, the other copolymerizable monomer (repeating unit), and the structure (repeating unit) derived from the styrene-based monomer, and a terpolymer of the structure (repeating unit) derived from the styrene-based monomer, the other copolymerizable monomer, and the styrene-based monomer, and a random copolymer block (repeating unit) containing the structure (repeating unit) derived from the styrene-based monomer and the other copolymerizable monomer and the styrene-based monomer. The styrene polymer may be a hydrogenated styrene copolymer obtained by hydrogenating the styrene copolymer. The styrene polymer may be a copolymer obtained by partially modifying the copolymer with maleic anhydride.

[0024] The styrene-based monomer is not particularly limited, but examples thereof include styrene, styrene derivatives, styrene in which some of the hydrogen atoms on the benzene ring have been substituted with alkyl groups, styrene in which some of the hydrogen atoms on the vinyl group have been substituted with alkyl groups, vinyltoluene, α-methylstyrene, butylstyrene, dimethylstyrene, and isopropenyltoluene. These styrene-based monomers may be used alone or in combination of two or more. Furthermore, the copolymerizable other monomer is not particularly limited, but examples thereof include olefins such as α-pinene, β-pinene, and dipentene, non-conjugated dienes such as 1,4-hexadiene and 3-methyl-1,4-hexadiene, and conjugated dienes such as 1,3-butadiene and 2-methyl-1,3-butadiene (isoprene). These copolymerizable other monomers may be used alone or in combination of two or more.

[0025] As the styrene-based polymer, a wide variety of conventionally known polymers can be used, and examples thereof include, but are not limited to, polymers having a structural unit represented by the following formula (4) (a structure derived from the styrene-based monomer) in the molecule:

[0026] In formula (1), R １ ~R ３ each independently represents a hydrogen atom or an alkyl group, and R ４ represents any group selected from the group consisting of a hydrogen atom, an alkyl group, an alkenyl group, and an isopropenyl group. The alkyl group is not particularly limited, and is preferably, for example, an alkyl group having 1 to 18 carbon atoms, and more preferably an alkyl group having 1 to 10 carbon atoms. Specific examples include a methyl group, an ethyl group, a propyl group, a hexyl group, and a decyl group. The alkenyl group is preferably an alkenyl group having 1 to 10 carbon atoms.

[0027] The styrene-based polymer preferably contains at least one structural unit represented by the formula (1), and may contain two or more different structural units in combination. The styrene-based polymer may also contain a structure in which the structural unit represented by the formula (1) is repeated.

[0028] The styrene-based polymer may have, in addition to the structural unit represented by formula (1), at least one of structural units represented by formulas (2), (3), and (4) below, and structures in which structural units represented by formulas (1), (2), and (3) below are repeated, as structural units derived from other monomers copolymerizable with the styrene-based monomer:

[0029]

[0030]

[0031] In the formula (2), the formula (3) and the formula (4), R ５ ~R ２２ are each independently a group selected from the group consisting of a hydrogen atom, an alkyl group, an alkenyl group, and an isopropenyl group. The alkyl group is not particularly limited, and is preferably, for example, an alkyl group having 1 to 18 carbon atoms, and more preferably, an alkyl group having 1 to 10 carbon atoms. Specific examples include a methyl group, an ethyl group, a propyl group, a hexyl group, and a decyl group. The alkenyl group is preferably an alkenyl group having 1 to 10 carbon atoms.

[0032] The styrene-based polymer preferably contains at least one structural unit represented by the formula (2), the formula (3), or the formula (4), and may contain two or more different structural units in combination. The styrene-based polymer may also have at least one structure in which the structural units represented by the formula (2), the formula (3), or the formula (4) are repeated.

[0033] More specifically, the structural unit represented by formula (1) includes structural units represented by the following formulas (5) to (7). The structural unit represented by formula (1) may also be a structure in which the structural units represented by formulas (5) to (7) are respectively repeated. The structural unit represented by formula (1) may be one of these alone or a combination of two or more different types.

[0034]

[0035]

[0036] More specifically, examples of the structural unit represented by formula (2) include structural units represented by the following formulas (8) to (14). The structural unit represented by formula (2) may also be a structure in which the structural units represented by formulas (8) to (14) below are respectively repeated. The structural unit represented by formula (2) may be one of these alone or a combination of two or more different types.

[0037]

[0038]

[0039]

[0040]

[0041]

[0042]

[0043] More specifically, the structural unit represented by formula (3) includes structural units represented by the following formulas (15) and (16). The structural unit represented by formula (3) may also be a structure in which the structural units represented by formula (15) and formula (16) are respectively repeated. The structural unit represented by formula (3) may be one of these alone or a combination of two or more different types.

[0044]

[0045] More specifically, the structural unit represented by the formula (4) includes structural units represented by the following formulas (17) and (18). The structural unit represented by the formula (4) may also be a structure in which the structural units represented by the following formulas (17) and (18) are respectively repeated. The structural unit represented by the formula (4) may be one of these alone or a combination of two or more different types.

[0046]

[0047]

[0048] Preferred examples of the styrene-based copolymer include polymers or copolymers obtained by polymerizing or copolymerizing one or more styrene-based monomers such as styrene, vinyltoluene, α-methylstyrene, isopropenyltoluene, divinylbenzene, and allylstyrene. More specific examples of the styrene-based copolymer include methylstyrene (ethylene / butylene) methylstyrene copolymer, methylstyrene (ethylene-ethylene / propylene) methylstyrene copolymer, styrene-isoprene copolymer, styrene-isoprene styrene copolymer, styrene (ethylene / butylene) styrene copolymer, styrene (ethylene-ethylene / propylene) styrene copolymer, styrene-butadiene styrene copolymer, butadiene styrene-butadiene copolymer such as butadiene styrene-butadiene oligomer, styrene (butadiene / butylene) styrene copolymer, methylstyrene (styrene / butadiene random copolymer block) methylstyrene copolymer, styrene (styrene / butadiene random copolymer block) styrene copolymer, and styrene-isobutylene styrene copolymer. Examples of the hydrogenated styrene-based copolymer include hydrogenated products of the styrene-based copolymers. More specific examples of the hydrogenated styrene copolymer include hydrogenated methylstyrene (ethylene / butylene) methylstyrene copolymer, hydrogenated methylstyrene (ethylene-ethylene / propylene) methylstyrene copolymer, hydrogenated styrene-isoprene copolymer, hydrogenated styrene-isoprene styrene copolymer, hydrogenated styrene (ethylene / butylene) styrene copolymer, hydrogenated styrene (ethylene-ethylene / propylene) styrene copolymer, hydrogenated methylstyrene (styrene / butadiene random copolymer block) methylstyrene copolymer, and hydrogenated styrene (styrene / butadiene random copolymer block) styrene copolymer.

[0049] As the styrene-based polymer, commercially available products may be used, and examples thereof include V9827, V9461, 2002, and 7125F manufactured by Kuraray Co., Ltd., FTR2140 and FTR6125 manufactured by Mitsui Chemicals, Inc., Tuftec H1041, Tuftec P1500, Tuftec H1221, and Tuftec M1913 manufactured by Asahi Kasei Corporation, liquid 1,2-SBS manufactured by Nippon Soda Co., Ltd., and Ricon 181 and Ricon 184 manufactured by Cray Valley.

[0050] The elastomer (the styrene-based polymer) preferably has a weight-average molecular weight of 1,000 to 300,000, more preferably 1,200 to 200,000. If the molecular weight is too low, the glass transition temperature of the cured product of the resin composition tends to decrease, and the heat resistance tends to decrease. If the molecular weight is too high, the viscosity of the resin composition when made into a varnish or when heat-molded tends to become too high. The weight-average molecular weight may be measured by a general molecular weight measurement method, and specific examples include values ​​measured using gel permeation chromatography (GPC).

[0051] The elastomers may be used alone or in combination of two or more.

[0052] (Curable Compound) The resin composition may contain at least one curable compound selected from the group consisting of a polyphenylene ether compound, a maleimide compound, and a hydrocarbon-based compound. The resin composition may also contain a curing agent. The curing agent is preferably contained in the resin composition when the resin composition contains the polyphenylene ether compound as the curable compound. That is, the resin composition preferably contains the polyphenylene ether compound and the curing agent. The resin composition preferably contains a maleimide compound and a hydrocarbon-based compound.

[0053] (Polyphenylene Ether Compound) The polyphenylene ether compound is not particularly limited, and examples thereof include polyphenylene ether compounds having a carbon-carbon unsaturated double bond at a terminal thereof. Examples of the polyphenylene ether compound include polyphenylene ether compounds having a carbon-carbon unsaturated double bond at a molecular terminal thereof, and more specifically, polyphenylene ether compounds having a substituent having a carbon-carbon unsaturated double bond at a molecular terminal thereof, such as modified polyphenylene ether compounds whose terminals are modified with a substituent having a carbon-carbon unsaturated double bond.

[0054] Examples of the substituent having a carbon-carbon unsaturated double bond include a group represented by the following formula (19) and a group represented by the following formula (20). That is, examples of the polyphenylene ether compound include a polyphenylene ether compound having at least one selected from the group represented by the following formula (19) and the group represented by the following formula (20) at a molecular end.

[0055] In formula (19), R ２３ ~R ２５ are independent of each other. That is, R ２３ ~R ２５ may be the same group or different groups. ２３ ~R ２５ represents a hydrogen atom or an alkyl group. Ar represents an arylene group. p represents an integer of 0 to 10. In addition, in the formula (19), when p is 0, it means that Ar is directly bonded to the end of the polyphenylene ether.

[0056] The arylene group is not particularly limited. Examples of the arylene group include monocyclic aromatic groups such as a phenylene group and polycyclic aromatic groups such as a naphthalene ring. The arylene group also includes derivatives in which a hydrogen atom bonded to the aromatic ring is substituted with a functional group such as an alkenyl group, an alkynyl group, a formyl group, an alkylcarbonyl group, an alkenylcarbonyl group, or an alkynylcarbonyl group.

[0057] The alkyl group is not particularly limited, and is preferably, for example, an alkyl group having 1 to 18 carbon atoms, more preferably an alkyl group having 1 to 10 carbon atoms. Specific examples include a methyl group, an ethyl group, a propyl group, a hexyl group, and a decyl group.

[0058] In formula (20), R ２６ represents a hydrogen atom or an alkyl group. The alkyl group is not particularly limited, and is preferably, for example, an alkyl group having 1 to 18 carbon atoms, more preferably an alkyl group having 1 to 10 carbon atoms. Specific examples include a methyl group, an ethyl group, a propyl group, a hexyl group, and a decyl group.

[0059] Examples of the group represented by the formula (19) include a vinylbenzyl group (ethenylbenzyl group) represented by the following formula (21): Furthermore, examples of the group represented by the formula (20) include an acryloyl group and a methacryloyl group.

[0060] More specifically, examples of the substituent include vinylbenzyl groups (ethenylbenzyl groups) such as o-ethenylbenzyl groups, m-ethenylbenzyl groups, and p-ethenylbenzyl groups, vinylphenyl groups, acryloyl groups, and methacryloyl groups. The polyphenylene ether compound may have one type of substituent, or two or more types. The polyphenylene ether compound may have, for example, any one of an o-ethenylbenzyl group, an m-ethenylbenzyl group, and a p-ethenylbenzyl group, or may have two or three types of these.

[0061] The polyphenylene ether compound has a polyphenylene ether chain in the molecule, and preferably has, for example, a repeating unit represented by the following formula (22) in the molecule.

[0062] In formula (22), t represents 1 to 50. ２７ ~R ３０ are independent of each other. That is, R ２７ ~R ３０may be the same group or different groups. ２７ ~R ３０ represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, a formyl group, an alkylcarbonyl group, an alkenylcarbonyl group, or an alkynylcarbonyl group, among which a hydrogen atom and an alkyl group are preferred.

[0063] R ２７ ~R ３０ Specific examples of the functional groups mentioned in the above include the following:

[0064] The alkyl group is not particularly limited, but is preferably an alkyl group having 1 to 18 carbon atoms, and more preferably an alkyl group having 1 to 10 carbon atoms. Specific examples include a methyl group, an ethyl group, a propyl group, a hexyl group, and a decyl group.

[0065] The alkenyl group is not particularly limited, but is preferably an alkenyl group having 2 to 18 carbon atoms, and more preferably an alkenyl group having 2 to 10 carbon atoms. Specific examples include a vinyl group, an allyl group, and a 3-butenyl group.

[0066] The alkynyl group is not particularly limited, but is preferably an alkynyl group having 2 to 18 carbon atoms, and more preferably an alkynyl group having 2 to 10 carbon atoms. Specific examples include an ethynyl group and a prop-2-yn-1-yl group (propargyl group).

[0067] The alkylcarbonyl group is not particularly limited as long as it is a carbonyl group substituted with an alkyl group, but for example, an alkylcarbonyl group having 2 to 18 carbon atoms is preferred, and an alkylcarbonyl group having 2 to 10 carbon atoms is more preferred. Specific examples include an acetyl group, a propionyl group, a butyryl group, an isobutyryl group, a pivaloyl group, a hexanoyl group, an octanoyl group, and a cyclohexylcarbonyl group.

[0068] The alkenylcarbonyl group is not particularly limited as long as it is a carbonyl group substituted with an alkenyl group, but for example, an alkenylcarbonyl group having 3 to 18 carbon atoms is preferred, and an alkenylcarbonyl group having 3 to 10 carbon atoms is more preferred. Specific examples include an acryloyl group, a methacryloyl group, and a crotonoyl group.

[0069] The alkynylcarbonyl group is not particularly limited as long as it is a carbonyl group substituted with an alkynyl group, but for example, an alkynylcarbonyl group having 3 to 18 carbon atoms is preferred, and an alkynylcarbonyl group having 3 to 10 carbon atoms is more preferred. Specific examples include a propioloyl group.

[0070] The weight-average molecular weight (Mw) and number-average molecular weight (Mn) of the polyphenylene ether compound are not particularly limited, and specifically, are preferably 500 to 5,000, more preferably 800 to 4,000, and even more preferably 1,000 to 3,000. The weight-average molecular weight and number-average molecular weight may be measured by a general molecular weight measurement method, specifically, values ​​measured using gel permeation chromatography (GPC) may be used. Furthermore, when the polyphenylene ether compound has a repeating unit represented by formula (22) in the molecule, t is preferably a value such that the weight-average molecular weight and number-average molecular weight of the polyphenylene ether compound fall within the above ranges. Specifically, t is preferably 1 to 50.

[0071] When the weight-average molecular weight and number-average molecular weight of the polyphenylene ether compound are within the above ranges, the compound has the excellent low dielectric properties of polyphenylene ether, and the cured product not only has excellent heat resistance but also has excellent moldability. This is believed to be due to the following reasons. When the weight-average molecular weight and number-average molecular weight are within the above ranges, ordinary polyphenylene ethers have a relatively low molecular weight, which tends to reduce heat resistance. In this regard, the polyphenylene ether compound according to the present embodiment has one or more unsaturated double bonds at its terminals, and therefore, as the curing reaction progresses, it is believed that a cured product with sufficiently high heat resistance can be obtained. Furthermore, when the weight-average molecular weight and number-average molecular weight of the polyphenylene ether compound are within the above ranges, it is believed that the compound has a relatively low molecular weight and therefore has excellent moldability. Therefore, it is believed that such polyphenylene ether compounds not only have excellent heat resistance but also have excellent moldability.

[0072] The average number of the substituents (number of terminal functional groups) at the molecular terminals per molecule of the polyphenylene ether compound is not particularly limited. Specifically, it is preferably 1 to 5, more preferably 1 to 3, and even more preferably 1.5 to 3. If the number of terminal functional groups is too small, it tends to be difficult to obtain a cured product with sufficient heat resistance. On the other hand, if the number of terminal functional groups is too large, the reactivity becomes too high, which may cause problems such as reduced shelf life and reduced fluidity of the resin composition. In other words, when such a polyphenylene ether compound is used, insufficient fluidity may cause molding defects such as the generation of voids during multilayer molding, making it difficult to obtain a highly reliable printed wiring board.

[0073] The number of terminal functional groups of a polyphenylene ether compound can be exemplified by a numerical value representing the average number of the substituents per molecule of all polyphenylene ether compounds present in 1 mole of the polyphenylene ether compound. The number of terminal functional groups can be measured, for example, by measuring the number of hydroxyl groups remaining in the obtained polyphenylene ether compound and calculating the difference from the number of hydroxyl groups in the polyphenylene ether before it has the substituents (before modification). This difference from the number of hydroxyl groups in the polyphenylene ether before modification is the number of terminal functional groups. The number of hydroxyl groups remaining in the polyphenylene ether compound can be measured by adding a quaternary ammonium salt (tetraethylammonium hydroxide) that associates with hydroxyl groups to a solution of the polyphenylene ether compound and measuring the UV absorbance of the resulting mixed solution.

[0074] The intrinsic viscosity of the polyphenylene ether compound is not particularly limited. Specifically, it may be 0.03 to 0.12 dl / g, preferably 0.04 to 0.11 dl / g, and more preferably 0.06 to 0.095 dl / g. If the intrinsic viscosity is too low, the molecular weight tends to be low, and it tends to be difficult to achieve low dielectric properties such as a low dielectric constant and a low dielectric loss tangent. On the other hand, if the intrinsic viscosity is too high, the viscosity tends to be high, sufficient fluidity cannot be achieved, and the moldability of the cured product tends to be reduced. Therefore, if the intrinsic viscosity of the polyphenylene ether compound is within the above range, excellent heat resistance and moldability of the cured product can be achieved.

[0075] The intrinsic viscosity here is the intrinsic viscosity measured in methylene chloride at 25° C., and more specifically, it is the value measured, for example, with a viscometer using a 0.18 g / 45 ml methylene chloride solution (liquid temperature: 25° C.). Examples of such viscometers include the AVS500 Visco System manufactured by Schott.

[0076] Examples of the polyphenylene ether compound include a polyphenylene ether compound represented by the following formula (23) and a polyphenylene ether compound represented by the following formula (24). As the polyphenylene ether compound, these polyphenylene ether compounds may be used alone, or these two types of polyphenylene ether compounds may be used in combination.

[0077]

[0078] In formula (23) and formula (24), R ３１ ~R ３８ and R ３９ ~R ４２ are independent of each other. That is, R ３１ ~R ３８ and R ３９ ~R ４２ may be the same group or different groups. ３１ ~R ３８ and R ３９ ~R ４２ represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, a formyl group, an alkylcarbonyl group, an alkenylcarbonyl group, or an alkynylcarbonyl group. １ and X ２ are independent of each other. １ and X ２ and may be the same group or different groups. １ and X ２ represents a substituent having a carbon-carbon unsaturated double bond. A and B represent repeating units represented by the following formulas (25) and (26), respectively. In addition, in formula (24), Y represents a linear, branched, or cyclic hydrocarbon having 20 or less carbon atoms.

[0079]

[0080] In the formulas (25) and (26), m and n each represent an integer of 0 to 20. ４７ ~R ５０ and R ５１ ~R ５４are independent of each other. That is, R ４７ ~R ５０ and R ５１ ~R ５４ may be the same group or different groups. ４７ ~R ５０ and R ５１ ~R ５４ represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, a formyl group, an alkylcarbonyl group, an alkenylcarbonyl group, or an alkynylcarbonyl group.

[0081] The polyphenylene ether compound represented by the formula (23) and the polyphenylene ether compound represented by the formula (24) are not particularly limited as long as they satisfy the above-mentioned constitution. Specifically, in the formula (23) and the formula (24), R ３１ ~R ３８ and R ３９ ~R ４２ As described above, each of R is independent. ３１ ~R ３８ and R ３９ ~R ４２ may be the same group or different groups. ３１ ~R ３８ and R ３９ ~R ４２ represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, a formyl group, an alkylcarbonyl group, an alkenylcarbonyl group, or an alkynylcarbonyl group, among which a hydrogen atom and an alkyl group are preferred.

[0082] In formula (25) and formula (26), m and n each preferably represent a value of 0 to 20, as described above. Furthermore, it is preferable that m and n represent a numerical value such that the sum of m and n is 1 to 30. Therefore, it is more preferable that m represents a value of 0 to 20, n represents a value of 0 to 20, and the sum of m and n represents a value of 1 to 30. Furthermore, R ４７ ~R ５０ and R ５１ ~R ５４ are independent of each other. That is, R ４７ ~R ５０ and R５１ ~R ５４ may be the same group or different groups. ４７ ~R ５０ and R ５１ ~R ５４ represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, a formyl group, an alkylcarbonyl group, an alkenylcarbonyl group, or an alkynylcarbonyl group, among which a hydrogen atom and an alkyl group are preferred.

[0083] R ３１ ~R ５４ is R in the above formula (22). ２７ ~R ３０ is the same as

[0084] In the formula (24), as described above, Y is a linear, branched, or cyclic hydrocarbon having 20 or less carbon atoms. Examples of Y include a group represented by the following formula (27).

[0085] In the formula (27), R ５５ and R ５６ are each independently a hydrogen atom or an alkyl group. Examples of the alkyl group include a methyl group. Examples of the group represented by formula (27) include a methylene group, a methylmethylene group, and a dimethylmethylene group, and among these, a dimethylmethylene group is preferred.

[0086] In the formula (23) and the formula (24), X １ and X ２ are each independently a substituent having a carbon-carbon double bond. In the polyphenylene ether compound represented by the formula (23) and the polyphenylene ether compound represented by the formula (24), X １ and X ２ may be the same group or different groups.

[0087] More specific examples of the polyphenylene ether compound represented by the formula (23) include polyphenylene ether compounds represented by the following formula (28).

[0088] More specific examples of the polyphenylene ether compound represented by the formula (24) include a polyphenylene ether compound represented by the following formula (29) and a polyphenylene ether compound represented by the following formula (30).

[0089]

[0090] In the above formulas (28) to (30), m and n are the same as m and n in the above formulas (25) and (26). ２３ ~R ２５ , p and Ar are R in the above formula (19). ２３ ~R ２５ , p, and Ar. In the formulas (29) and (30), Y is the same as Y in the formula (24). In the formula (30), R ２６ is R in the above formula (20). ２６ is the same as

[0091] The method for synthesizing the polyphenylene ether compound used in the present embodiment is not particularly limited as long as it is possible to synthesize a polyphenylene ether compound having a carbon-carbon unsaturated double bond in the molecule. Specific examples of this method include a method of reacting polyphenylene ether with a compound in which a substituent having a carbon-carbon unsaturated double bond and a halogen atom are bonded.

[0092] Examples of the compound in which a substituent having a carbon-carbon unsaturated double bond and a halogen atom are bonded include compounds in which a halogen atom is bonded to a substituent represented by the formulas (19) to (21). Specific examples of the halogen atom include a chlorine atom, a bromine atom, an iodine atom, and a fluorine atom, with a chlorine atom being preferred. More specific examples of the compound in which a halogen atom is bonded to a substituent having a carbon-carbon unsaturated double bond include o-chloromethylstyrene, p-chloromethylstyrene, and m-chloromethylstyrene. The compound in which a halogen atom is bonded to a substituent having a carbon-carbon unsaturated double bond may be used alone or in combination of two or more. For example, o-chloromethylstyrene, p-chloromethylstyrene, and m-chloromethylstyrene may be used alone or in combination of two or more.

[0093] The polyphenylene ether used as a raw material is not particularly limited as long as it can ultimately synthesize a predetermined polyphenylene ether compound. Specific examples include polyphenylene ethers composed of 2,6-dimethylphenol and at least one of a bifunctional phenol and a trifunctional phenol, and compounds containing polyphenylene ether as a main component, such as poly(2,6-dimethyl-1,4-phenylene oxide). A bifunctional phenol is a phenolic compound having two phenolic hydroxyl groups per molecule, such as tetramethylbisphenol A. A trifunctional phenol is a phenolic compound having three phenolic hydroxyl groups per molecule.

[0094] The polyphenylene ether compound can be synthesized by the method described above. Specifically, the polyphenylene ether and the compound in which a substituent having a carbon-carbon unsaturated double bond and a halogen atom are bonded to each other are dissolved in a solvent and stirred. By doing so, the polyphenylene ether reacts with the compound in which a substituent having a carbon-carbon unsaturated double bond and a halogen atom are bonded to each other, thereby obtaining the polyphenylene ether compound used in this embodiment.

[0095] The reaction is preferably carried out in the presence of an alkali metal hydroxide. It is believed that this allows the reaction to proceed smoothly. This is believed to be because the alkali metal hydroxide functions as a dehydrohalogenating agent, specifically, a dehydrochlorinating agent. That is, it is believed that the alkali metal hydroxide eliminates hydrogen halide from the phenol group of the polyphenylene ether and the compound in which the substituent having a carbon-carbon unsaturated double bond and a halogen atom are bonded, and as a result, the substituent having a carbon-carbon unsaturated double bond is bonded to the oxygen atom of the phenol group in place of the hydrogen atom of the phenol group of the polyphenylene ether.

[0096] The alkali metal hydroxide is not particularly limited as long as it can act as a dehalogenating agent, and examples thereof include sodium hydroxide, etc. The alkali metal hydroxide is usually used in the form of an aqueous solution, specifically, an aqueous sodium hydroxide solution.

[0097] The reaction conditions, such as the reaction time and reaction temperature, vary depending on the compound in which the substituent having a carbon-carbon unsaturated double bond is bonded to a halogen atom, and are not particularly limited as long as the conditions are such that the reaction proceeds favorably. Specifically, the reaction temperature is preferably room temperature to 100°C, and more preferably 30 to 100°C. The reaction time is preferably 0.5 to 20 hours, and more preferably 0.5 to 10 hours.

[0098] The solvent used in the reaction is not particularly limited as long as it can dissolve the polyphenylene ether and the compound in which a substituent having a carbon-carbon unsaturated double bond and a halogen atom are bonded, and does not inhibit the reaction between the polyphenylene ether and the compound in which a substituent having a carbon-carbon unsaturated double bond and a halogen atom are bonded. Specific examples include toluene.

[0099] The above reaction is preferably carried out in the presence of not only an alkali metal hydroxide but also a phase transfer catalyst. That is, the above reaction is preferably carried out in the presence of an alkali metal hydroxide and a phase transfer catalyst. Doing so is believed to allow the reaction to proceed more smoothly. This is believed to be due to the following: A phase transfer catalyst has the function of incorporating an alkali metal hydroxide, is soluble in both a polar solvent phase such as water and a nonpolar solvent phase such as an organic solvent, and is capable of transferring between these phases. Specifically, when an aqueous solution of sodium hydroxide is used as the alkali metal hydroxide and an organic solvent such as toluene, which is incompatible with water, is used as the solvent, even if the aqueous solution of sodium hydroxide is added dropwise to the solvent being used for the reaction, the solvent and the aqueous solution of sodium hydroxide separate, and it is believed that the sodium hydroxide is unlikely to migrate to the solvent. In this case, it is believed that the aqueous solution of sodium hydroxide added as the alkali metal hydroxide is unlikely to contribute to promoting the reaction. On the other hand, when the reaction is carried out in the presence of an alkali metal hydroxide and a phase transfer catalyst, the alkali metal hydroxide is transferred to the solvent while being incorporated into the phase transfer catalyst, and the aqueous sodium hydroxide solution is thought to contribute more to promoting the reaction. Therefore, when the reaction is carried out in the presence of an alkali metal hydroxide and a phase transfer catalyst, the reaction is thought to proceed more smoothly.

[0100] The phase transfer catalyst is not particularly limited, but examples thereof include quaternary ammonium salts such as tetra-n-butylammonium bromide.

[0101] The resin composition used in the present embodiment preferably contains the polyphenylene ether compound obtained as described above as the polyphenylene ether compound.

[0102] (Maleimide Compound) The maleimide compound is not particularly limited as long as it is a maleimide compound having a maleimide group in the molecule. Examples of the maleimide compound include maleimide compounds having an arylene structure in the molecule that is oriented and bonded at the meta position, maleimide compounds having an indane structure in the molecule, and maleimide compounds having an arylene structure and an indane structure in the molecule that are oriented and bonded at the meta position. The maleimide compound may contain either one of these or may contain two of these.

[0103] The maleimide compound having an arylene structure in the molecule oriented to the meta position is not particularly limited, as long as it has the arylene structure in the molecule. Examples of the arylene structure include an arylene structure in which a structure containing a maleimide group is bonded to the meta position (an arylene structure in which a structure containing a maleimide group is substituted at the meta position). The arylene group is not particularly limited as long as it is an arylene group oriented to the meta position, and examples include m-arylene groups such as an m-phenylene group and an m-naphthylene group. As the maleimide compound having an arylene structure in the molecule oriented to the meta position, commercially available products can be used, and for example, the solid content of MIR-5000-60T manufactured by Nippon Kayaku Co., Ltd. may be used.

[0104] The maleimide compound having an indane structure in the molecule is not particularly limited as long as it is a maleimide compound having an indane structure in the molecule. Examples of the indane structure include a divalent group formed by removing two hydrogen atoms from indane or indane substituted with a substituent. The maleimide compound having an indane structure in the molecule also has a maleimide group in the molecule.

[0105] Specific examples of methods for producing the maleimide compound having an indane structure in its molecule include a method of reacting an amine compound with maleic anhydride in an organic solvent such as toluene in the presence of a catalyst such as toluenesulfonic acid, which is known as a maleimide reaction. Specifically, after the maleimide reaction, unreacted maleic anhydride and other impurities are removed by washing with water or the like, and the solvent is removed under reduced pressure to obtain the maleimide compound having an indane structure in its molecule. A dehydrating agent may be used during this reaction. Commercially available products may also be used as the maleimide compound having an indane structure in its molecule.

[0106] Examples of the maleimide compound having an arylene structure and an indane structure oriented and bonded at the meta position in the molecule include maleimide compounds having the arylene structure and the indane structure in the molecule.

[0107] The maleimide compound may be, for example, a maleimide compound having an arylene structure oriented to the meta position in the molecule, a maleimide compound having an indane structure in the molecule, or a maleimide compound other than the maleimide compound having an arylene structure and an indane structure oriented to the meta position in the molecule (another maleimide compound). The other maleimide compound is a maleimide compound having a maleimide group in the molecule and not having an arylene structure and an indane structure oriented to the meta position in the molecule, and examples thereof include a maleimide compound having one or more maleimide groups in the molecule and a modified maleimide compound. Examples of the other maleimide compounds include phenylmaleimide compounds such as 4,4'-diphenylmethane bismaleimide, polyphenylmethane maleimide, m-phenylene bismaleimide, bisphenol A diphenyl ether bismaleimide, 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethane bismaleimide, 4-methyl-1,3-phenylene bismaleimide, and biphenylaralkyl polymaleimide compounds, as well as N-alkyl bismaleimide compounds having an aliphatic skeleton. Examples of the modified maleimide compounds include modified maleimide compounds in which a portion of the molecule is modified with an amine compound, and modified maleimide compounds in which a portion of the molecule is modified with a silicone compound. Commercially available products can also be used as the other maleimide compounds, such as BMI-4000 and BMI-5100 manufactured by Daiwa Chemical Industry Co., Ltd., and BMI-5100 manufactured by Designer Molecules Inc. BMI-689, BMI-1500, BMI-3000J, etc. manufactured by Epson Corporation may also be used.

[0108] The maleimide compounds may be used alone or in combination of two or more.

[0109] (Hydrocarbon Compound) The hydrocarbon compound is not particularly limited as long as it is a thermosetting hydrocarbon compound. Examples of the hydrocarbon compound include hydrocarbon compounds represented by the following formula (31):

[0110] In formula (31), Z represents a hydrocarbon group having 6 or more carbon atoms, including at least one selected from an aromatic cyclic group and an aliphatic cyclic group, and a represents 1 to 10.

[0111] The aromatic cyclic group is not particularly limited, but examples thereof include a phenylene group, a xylylene group, a naphthylene group, a tolylene group, and a biphenylene group. The aliphatic cyclic group is not particularly limited, but examples thereof include a group containing an indane structure and a group containing a cycloolefin structure. Among these, Z is preferably an aromatic cyclic group, and more preferably a xylylene group. The number of carbon atoms in the hydrocarbon group is not particularly limited as long as it is 6 or more, but is preferably 6 to 20.

[0112] More specifically, the hydrocarbon compound represented by the formula (31) includes a hydrocarbon compound represented by the following formula (32): In addition, the hydrocarbon compound preferably includes a hydrocarbon compound represented by the following formula (32):

[0113] In formula (32), n represents 1 to 10.

[0114] Examples of the hydrocarbon-based compound include aromatic polymers having structural units derived from bifunctional aromatic compounds, such as divinyl aromatic compounds, in which two carbon-carbon unsaturated double bonds are bonded to an aromatic ring. The structural units derived from bifunctional aromatic compounds are structural units obtained by polymerizing the bifunctional aromatic compounds. Examples of the bifunctional aromatic compounds include divinylbenzenes such as m-divinylbenzene and p-divinylbenzene, with p-divinylbenzene being more preferred. The aromatic polymer may contain not only structural units derived from the bifunctional aromatic compounds but also other structural units. Examples of such other structural units include structural units derived from monofunctional aromatic compounds, such as monovinyl aromatic compounds, in which one carbon-carbon unsaturated double bond is bonded to an aromatic ring. Examples of the monovinyl aromatic compounds include ethylvinyl aromatic compounds. The structural units derived from monofunctional aromatic compounds are structural units obtained by polymerizing the monofunctional aromatic compounds. When the aromatic polymer has not only the structural unit derived from the bifunctional aromatic compound but also other structural units, it is a copolymer of the structural unit derived from the bifunctional aromatic compound and other structural units, such as the structural unit derived from the monofunctional aromatic compound. This copolymer may be a block copolymer or a random copolymer. As described above, examples of the hydrocarbon-based compound include the aromatic polymers, and among these, for example, a polyfunctional vinyl aromatic copolymer can be mentioned. For example, the polyfunctional vinyl aromatic copolymer can be a copolymer having a repeating unit (a) derived from a divinyl aromatic compound and a repeating unit (b) derived from a monovinyl aromatic compound. The contents of the repeating units (a) and (b) in the polyfunctional vinyl aromatic copolymer are not particularly limited, but when the sum of the repeating units (a) and (b) is taken as 100 mol%, it is preferable that the repeating unit (a) is contained in an amount of 2 mol% or more but less than 95 mol%, and the repeating unit (b) is contained in an amount of 5 mol% or more but less than 98 mol%.The molecular weight of the polyfunctional vinyl aromatic copolymer is not particularly limited, but preferably has a number average molecular weight (Mn) of 300 to 10,000. Examples of the polyfunctional vinyl aromatic copolymer include the polyfunctional vinyl aromatic copolymers described in JP 2018-168347 A. The hydrocarbon compound preferably contains at least one of the polyfunctional vinyl aromatic copolymer and a hydrocarbon compound represented by formula (31).

[0115] (Curing Agent) As described above, the resin composition may contain a curing agent that reacts with the curable compound, if necessary. Here, the curing agent refers to a compound that reacts with the curable compound and contributes to curing of the resin composition. Examples of the curing agent include epoxy compounds, methacrylate compounds, acrylate compounds, vinyl compounds, cyanate ester compounds, active ester compounds, and allyl compounds.

[0116] The epoxy compound is a compound having an epoxy group in the molecule, and specific examples thereof include bisphenol-type epoxy compounds such as bisphenol A-type epoxy compounds, phenol novolac-type epoxy compounds, cresol novolac-type epoxy compounds, dicyclopentadiene-type epoxy compounds, bisphenol A novolac-type epoxy compounds, biphenyl aralkyl-type epoxy compounds, and naphthalene ring-containing epoxy compounds. The epoxy compound also includes epoxy resins, which are polymers of the above-mentioned epoxy compounds.

[0117] The methacrylate compound is a compound having a methacryloyl group in the molecule, and examples thereof include monofunctional methacrylate compounds having one methacryloyl group in the molecule and polyfunctional methacrylate compounds having two or more methacryloyl groups in the molecule. Examples of the monofunctional methacrylate compound include methyl methacrylate, ethyl methacrylate, propyl methacrylate, and butyl methacrylate. Examples of the polyfunctional methacrylate compound include dimethacrylate compounds such as tricyclodecane dimethanol dimethacrylate (DCP).

[0118] The acrylate compound is a compound having an acryloyl group in the molecule, and examples thereof include monofunctional acrylate compounds having one acryloyl group in the molecule and polyfunctional acrylate compounds having two or more acryloyl groups in the molecule. Examples of the monofunctional acrylate compound include methyl acrylate, ethyl acrylate, propyl acrylate, and butyl acrylate. Examples of the polyfunctional acrylate compound include diacrylate compounds such as tricyclodecane dimethanol diacrylate.

[0119] The vinyl compound is a compound having a vinyl group in the molecule, and examples thereof include monofunctional vinyl compounds (monovinyl compounds) having one vinyl group in the molecule and polyfunctional vinyl compounds having two or more vinyl groups in the molecule. Examples of the polyfunctional vinyl compound include divinylbenzene, curable polybutadiene having a carbon-carbon unsaturated double bond in the molecule, and curable butadiene-styrene copolymer having a carbon-carbon unsaturated double bond in the molecule.

[0120] The cyanate ester compound is a compound having a cyanate group in the molecule, and examples thereof include 2,2-bis(4-cyanatephenyl)propane, bis(3,5-dimethyl-4-cyanatephenyl)methane, and 2,2-bis(4-cyanatephenyl)ethane.

[0121] The active ester compound is a compound having an ester group with high reactivity in the molecule, and examples thereof include benzenecarboxylic acid active ester, benzenedicarboxylic acid active ester, benzenetricarboxylic acid active ester, benzenetetracarboxylic acid active ester, naphthalenecarboxylic acid active ester, naphthalenedicarboxylic acid active ester, naphthalenetricarboxylic acid active ester, naphthalenetetracarboxylic acid active ester, fluorenecarboxylic acid active ester, fluorenedicarboxylic acid active ester, fluorenetricarboxylic acid active ester, and fluorenetetracarboxylic acid active ester.

[0122] The allyl compound is a compound having an allyl group in the molecule, and examples thereof include triallyl isocyanurate compounds such as triallyl isocyanurate (TAIC), diallyl bisphenol compounds, and diallyl phthalate (DAP).

[0123] The curing agent may be used alone or in combination of two or more kinds.

[0124] The weight-average molecular weight of the curing agent is not particularly limited, but is preferably 100 to 5000, more preferably 100 to 4000, and even more preferably 100 to 3000. If the weight-average molecular weight of the curing agent is too low, the curing agent may be more likely to volatilize from the resin composition's blending components. Furthermore, if the weight-average molecular weight of the curing agent is too high, the viscosity of the resin composition varnish or the melt viscosity when the resin composition is brought to a B-stage may become too high, resulting in poor moldability and a poor appearance after molding. Therefore, when the weight-average molecular weight of the curing agent is within this range, a resin composition with excellent heat resistance and moldability of the cured product can be obtained. This is thought to be because the resin composition can be cured appropriately. The weight-average molecular weight may be measured using a common molecular weight measurement method, specifically, a value measured using gel permeation chromatography (GPC), etc.

[0125] The average number of functional groups per molecule of the curing agent that contribute to the reaction during curing of the resin composition (number of functional groups) varies depending on the weight-average molecular weight of the curing agent, but is preferably 1 to 20, and more preferably 2 to 18. If the number of functional groups is too small, it tends to be difficult to obtain sufficient heat resistance of the cured product. On the other hand, if the number of functional groups is too large, the reactivity becomes too high, which may cause problems such as reduced shelf life and reduced fluidity of the resin composition.

[0126] (Content) The content of the elastomer is preferably more than 10% by mass, more preferably more than 10% by mass but not more than 40% by mass, and even more preferably 15 to 35% by mass, relative to the resin composition. The content of the curable compound is preferably less than 80% by mass, more preferably 20% by mass or more but less than 80% by mass, and even more preferably 30 to 70% by mass, relative to the resin composition. When the contents of the elastomer and the curable compound are each within the above ranges, a cured product with a low dielectric constant (for example, a dielectric constant of less than 2.6 at 10 GHz) can be obtained.

[0127] (Other Components) The resin composition may contain, as necessary, components other than the filler, the elastomer, and the curable compound (other components) within a range that does not impair the effects of the present invention. Examples of other components contained in the resin composition may include additives such as a reaction initiator, a reaction accelerator, a catalyst, a polymerization retarder, a polymerization inhibitor, a dispersant, a leveling agent, a silane coupling agent, an antifoaming agent, an antioxidant, a heat stabilizer, an antistatic agent, an ultraviolet absorber, a dye or pigment, and a lubricant.

[0128] As described above, the resin composition may contain a reaction initiator. The reaction initiator is not particularly limited as long as it can accelerate the curing reaction of the resin composition, and examples thereof include peroxides and organic azo compounds. Examples of peroxides include α,α'-bis(t-butylperoxy-m-isopropyl)benzene, 2,5-dimethyl-2,5-di(t-butylperoxy)-3-hexyne, and benzoyl peroxide. Examples of organic azo compounds include azobisisobutyronitrile. If necessary, a metal carboxylate or the like can be used in combination. This can further accelerate the curing reaction. Among these, α,α'-bis(t-butylperoxy-m-isopropyl)benzene is preferably used. α,α'-bis(t-butylperoxy-m-isopropyl)benzene has a relatively high reaction initiation temperature, which can suppress acceleration of the curing reaction when curing is not required, such as during prepreg drying, thereby suppressing deterioration of the shelf life of the resin composition. Furthermore, since α,α'-bis(t-butylperoxy-m-isopropyl)benzene has low volatility, it does not volatilize during drying or storage of the prepreg, and has good stability. The reaction initiators may be used alone or in combination of two or more.

[0129] As described above, the resin composition may contain a silane coupling agent. The silane coupling agent may be contained in the resin composition, or may be contained as a silane coupling agent that has been surface-treated in advance in a filler contained in the resin composition. Among these, the silane coupling agent is preferably contained as a silane coupling agent that has been surface-treated in advance in a filler, and it is more preferable to contain the silane coupling agent in advance in the filler in this way, and further to contain the silane coupling agent in the resin composition. Furthermore, in the case of a prepreg, the prepreg may contain the silane coupling agent that has been surface-treated in advance in a fibrous substrate. Examples of the silane coupling agent include the same silane coupling agents as those used in the surface treatment of the filler described above.

[0130] As described above, the resin composition may contain a flame retardant. The inclusion of a flame retardant can enhance the flame retardancy of the cured resin composition. The flame retardant is not particularly limited. Specifically, in fields where halogen-based flame retardants such as bromine-based flame retardants are used, for example, ethylene dipentabromobenzene, ethylene bistetrabromoimide, decabromodiphenyl oxide, and tetradecabromodiphenoxybenzene, which have melting points of 300°C or higher, are preferred. The use of a halogen-based flame retardant is believed to suppress halogen elimination at high temperatures and prevent a decrease in heat resistance. Furthermore, in fields where halogen-free materials are required, phosphorus-containing flame retardants (phosphorus-based flame retardants) are sometimes used. Examples of the phosphorus-based flame retardant include, but are not limited to, phosphate ester-based flame retardants, phosphazene-based flame retardants, phosphine oxide-based flame retardants, and phosphinate-based flame retardants. Specific examples of phosphate ester-based flame retardants include condensed phosphate esters of dixylenyl phosphate. A specific example of a phosphazene-based flame retardant is phenoxyphosphazene. A specific example of a phosphine oxide-based flame retardant is bisdiphenylphosphine oxide-based flame retardant, and a specific example of this is xylylenebisdiphenylphosphine oxide. A specific example of a phosphinate-based flame retardant is a metal phosphinate salt of an aluminum dialkylphosphinate. As the flame retardant, each of the exemplified flame retardants may be used alone or in combination of two or more.

[0131] (Production Method) The method for producing the resin composition is not particularly limited, and examples thereof include a method of mixing components constituting the resin composition, such as the filler, the elastomer, and the curable compound, to a predetermined content. The method for producing a cured product of the resin composition is not particularly limited, and examples thereof include a method of curing the resin composition by heating the resin composition.

[0132] (Dielectric Properties) The cured product of the resin composition has a dielectric constant at 10 GHz of less than 2.6, preferably 1 or more but less than 2.4, and more preferably 1 or more but less than 2.2. A cured product with such a dielectric constant can reduce signal transmission loss in conductor wiring (conductor circuit) formed on the cured product. The cured product of the resin composition also has a dielectric loss tangent at 10 GHz of preferably 0.005 or less, more preferably 0.0001 to 0.005, and even more preferably 0.0001 to 0.003. The dielectric constant and dielectric loss tangent here refer to the dielectric constant and dielectric loss tangent of the insulating layer at a frequency of 10 GHz, and examples thereof include the dielectric constant and dielectric loss tangent of the insulating layer at a frequency of 10 GHz measured by a cavity resonator perturbation method.

[0133] (Surface roughness) The surface roughness Ra of the cured product of the resin composition is less than 100 nm, preferably 1 nm or more and less than 80 nm, and more preferably 1 nm or more and less than 60 nm. If the surface roughness Ra is too high, the surface roughness Ra after plasma treatment tends to be unable to remain low. Therefore, if the surface roughness Ra is within the above range, a cured product with a low surface roughness Ra after plasma treatment can be obtained. Note that Ra is the arithmetic mean height of the roughness curve as defined in JIS B 0601:2001. Examples of Ra include values ​​measured using a surface roughness measuring instrument, a laser microscope, and an atomic force microscope. More specifically, examples of Ra include values ​​measured using surface roughness analysis using a scanning confocal laser microscope (LEXT OLS3000 manufactured by Olympus Corporation).

[0134] (Thermal Expansion Coefficient) The thermal expansion coefficient (CTE) of the cured product of the resin composition is preferably less than 80 ppm / °C, preferably 15 to 65 ppm / °C, and more preferably 15 to 55 ppm / °C. When the thermal expansion coefficient is within the above range, the dimensional change rate of the cured product of the resin composition due to heating is small. The thermal expansion coefficient is a value expressed per 1°C of the rate at which the length of an object expands due to an increase in temperature, and examples thereof include the thermal expansion coefficient measured by the TMA (thermo-mechanical analysis) method. More specifically, examples thereof include the thermal expansion coefficient when measured by the TMA method in a temperature range of 50 to 100°C.

[0135] (Storage Modulus) The storage modulus E' of the cured product of the resin composition is preferably 4 GPa or less, more preferably 0.5 to 3 GPa. When the storage modulus is within the above range, the cured product of the resin composition is relatively soft, and the stress applied to, for example, a wiring board or a semiconductor package can be reduced. The storage modulus E' can be, for example, the storage modulus at 40°C when measured using a dynamic viscoelasticity measuring device.

[0136] (Wiring Board) The cured product of the resin composition according to this embodiment can be used for the manufacture of a wiring board, etc. For example, the cured product of the resin composition according to this embodiment can be used as an insulating layer provided on a wiring board. That is, a wiring board according to another embodiment of the present invention is a wiring board including an insulating layer containing the cured product (the cured product of the resin composition) and wiring.

[0137] The method for producing the wiring board is not particularly limited as long as it can produce a wiring board having an insulating layer containing the cured product and wiring. Specific examples of the production method include a production method such as that shown in Fig. 1. Fig. 1 is a schematic diagram for explaining an example of a method for producing a wiring board using the cured product according to this embodiment.

[0138] First, as shown in Fig. 1(a), a release film 13 having a resin layer 12 is placed on a support plate 11 so that the resin layer 12 contacts the surface 11a of the support plate 11. At this time, the support plate 11 and the resin layer 12 may be adhered to each other by vacuum lamination or the like. By doing so, the support plate 11 and the resin layer 12 are laminated, and the resin layer 12 is formed on the surface 11a of the support plate 11, as shown in Fig. 1(b). Note that here, a metal-clad laminate or the like having an insulating layer 112 and a metal foil 111 provided on the surface of the insulating layer 112 is used as the support plate 11, but the present invention is not limited thereto.

[0139] Next, as shown in Fig. 1(b), the resin layer 12 formed on the surface of the support plate 11 is cured with the release film 13 still attached. At this time, the resin layer 12 may be cured by vacuum curing (for example, curing by heating under vacuum) as described above. By doing so, an insulating layer 14 formed by curing the resin layer 12 is formed on the surface of the support plate 11 as shown in Fig. 1(c). Thereafter, the release film 13 is peeled off as shown in Fig. 1(c).

[0140] Next, as shown in FIG. 1( d ), a surface 14 a of the insulating layer 14 that is not in contact with the support plate 11 is subjected to plasma treatment to roughen the surface 14 a .

[0141] Next, a sputtering process is performed on the roughened surface 14a of the insulating layer 14, thereby forming a seed layer 15 on the roughened surface 14a of the insulating layer 14, as shown in FIG. 1( e). Here, the seed layer 15 includes a seed layer main body 152 and a seed adhesion layer 151 that improves adhesion of the seed layer main body 152 to the insulating layer 14, but is not limited thereto. Examples of the seed adhesion layer 151 include a Ti layer, and examples of the seed layer main body 152 include a Cu layer.

[0142] 1( f), a conductor layer 16 is formed using the seed layer 15. Specifically, by performing an electrolytic plating process using the seed layer 15, the conductor layer 16 integrated with the seed layer main body 152 can be formed. This conductor layer 16 may be formed to form a conductor wiring pattern.

[0143] In this manufacturing method, a layer containing the resin composition (e.g., a layer made of the resin composition) is used as the resin layer 12. Since the resin layer 12 is a layer containing the resin composition, the insulating layer 14 formed by curing the resin layer 12 is a layer containing a cured product of the resin composition (e.g., a layer made of the cured product of the resin composition). Therefore, this manufacturing method is a method for manufacturing a wiring board using a cured product of the resin composition. As described above, the cured product of the resin composition has a surface roughness Ra of less than 100 nm before the plasma treatment. Even after the cured product is subjected to the plasma treatment, the cured product of the resin composition can maintain a low surface roughness Ra, for example, less than 100 nm. Furthermore, the cured product of the resin composition has a low relative dielectric constant of less than 2.6 at 10 GHz. For these reasons, when a conductor wiring pattern is formed as the conductor layer 16 formed on the cured product, signal transmission loss in this conductor wiring (conductor circuit) can be reduced.

[0144] In the case of forming a conductor wiring pattern, the manufacturing method specifically includes a manufacturing method as shown in Fig. 2. Fig. 2 is a schematic diagram for explaining another example of a method for manufacturing a wiring board using the cured product according to the present embodiment.

[0145] First, as shown in FIG. 2( a), a release film 13 having a resin layer 12 is placed on a support plate 11 so that the resin layer 12 contacts the surface 11 a of the support plate 11, thereby forming the resin layer 12 on the surface of the support plate 11 as shown in FIG. 2( b).

[0146] 2(b), the resin layer 12 formed on the surface of the support plate 11 is cured with the release film 13 still attached. By doing so, an insulating layer 14 is formed on the surface of the support plate 11 by curing the resin layer 12.

[0147] Next, the insulating layer 14 obtained by curing the resin layer 12 is subjected to laser processing with the release film 13 still attached to form recesses 22 in the insulating layer 14. These recesses 22 correspond to the conductor wiring pattern that will ultimately be formed. The laser processing is not particularly limited as long as it can form recesses corresponding to the conductor wiring pattern in the insulating layer 14, and examples thereof include CO ２ Examples of the laser beam used for desmearing include a laser and a UV laser. Thereafter, the recesses 22 formed in the insulating layer 14 are subjected to a plasma desmearing treatment. By doing so, it is possible to remove residues (smears) of the insulating layer 14 generated by the laser processing from the recesses 22. The plasma desmearing treatment is not particularly limited as long as desmearing can be performed using plasma, and examples thereof include treatments similar to the plasma treatment described below. Here, a mixed gas plasma treatment of oxygen and carbon tetrafluoride (surface treatment using plasma generated using a mixed gas of oxygen and carbon tetrafluoride as a raw material gas) is preferred.

[0148] 2(d), the release film 13 is peeled off from the insulating layer 14 having the recesses 22 formed therein. Next, the surface 14a of the insulating layer 14 that is not in contact with the support plate 11 is subjected to the plasma treatment to roughen the surface 14a.

[0149] Next, a sputtering process is performed on the roughened surface 14a of the insulating layer 14, thereby forming a seed layer 15 on the roughened surface 14a of the insulating layer 14, as shown in FIG. 2(e).

[0150] Next, as shown in FIG. 2( f), a resist layer 18 is formed on the insulating layer 14 on which the seed layer 15 has been formed. Then, as shown in FIG. 2( g), the resist layer 18 is selectively exposed and developed so that the resist layer 18 remains in areas other than those where a conductor layer 19 is to be formed (areas corresponding to the final conductor wiring pattern). Next, as shown in FIG. 2( h), the conductor layer 19 is formed using the seed layer 15. Specifically, the conductor layer 19 integrated with the seed layer 15 can be formed by electrolytic plating using the seed layer 15. Then, as shown in FIG. 2( i), the resist layer 18 is peeled off. Then, as shown in FIG. 2( j), the portion of the conductor layer 19 corresponding to the seed layer 15 is removed by etching to form a conductor wiring pattern 20. Finally, as shown in FIG. 2( k), the conductor wiring pattern 20 may be covered with another insulating layer 31.

[0151] The manufacturing method may also form a conductor wiring pattern, etc., on the surface of the support plate opposite to the side on which the conductor wiring pattern, etc., is formed, by the same method as described above. That is, the manufacturing method may form a conductor wiring pattern, etc., on one side of the support plate, or may form a conductor wiring pattern, etc., on both sides. When forming a conductor wiring pattern, etc., on both sides, they may be formed simultaneously or at different times.

[0152] In this manufacturing method, a layer containing the resin composition (e.g., a layer made of the resin composition) is used as the resin layer 12. Since the resin layer 12 is a layer containing the resin composition, the insulating layer 14 formed by curing the resin layer 12 is a layer containing a cured product of the resin composition (e.g., a layer made of the cured product of the resin composition). Therefore, this manufacturing method is also a method for manufacturing a wiring board using a cured product of the resin composition. As described above, the cured product of the resin composition has a surface roughness Ra of less than 100 nm before the plasma treatment. Even after the cured product is subjected to the plasma treatment, the cured product of the resin composition can maintain a low surface roughness Ra, for example, less than 100 nm. Furthermore, the cured product of the resin composition has a low relative dielectric constant of less than 2.6 at 10 GHz. These factors reduce signal transmission loss in the conductor wiring pattern 20 formed on the cured product. Furthermore, by repeating the manufacturing method, a wiring board having a multilayered conductor wiring pattern 20 can be manufactured.

[0153] Based on the above, a method for manufacturing a wiring board using a cured resin composition according to this embodiment includes the steps of: (A) forming an insulating layer by curing a resin layer formed in contact with at least one surface of a support board; (B) roughening the surface of the insulating layer not in contact with the support board by plasma treatment; and (C) forming a seed layer on the roughened surface of the insulating layer by sputtering, wherein the insulating layer 14 is a layer made of the cured resin composition. The manufacturing method may further include the step of (D) forming a conductor wiring pattern on the seed layer. The wiring board may also be formed into a semiconductor package by mounting a semiconductor chip. That is, a semiconductor package according to another embodiment of the present invention includes the wiring board and a semiconductor chip mounted on the wiring board. Examples of the semiconductor package include a semiconductor package in which the semiconductor chip is connected to conductor wiring (conductor circuit) in the conductor wiring pattern.

[0154] The step (A) is not particularly limited as long as it can form an insulating layer by curing a resin layer formed so as to contact at least one surface of the support plate. The resin layer is not particularly limited as long as it is a layer containing the resin composition, and examples thereof include a layer made of the resin composition. Furthermore, the insulating layer is not particularly limited as long as it is a layer containing a cured product of the resin composition, and examples thereof include a layer made of the cured product of the resin composition.

[0155] Methods for forming the resin layer include, for example, a method of applying a resin composition to the support plate (application method) and a method of laminating a resin film on the support plate (lamination method). Specific examples of the application method include a method of applying a fluid resin composition (such as a resin varnish or a resin solution) to the support plate and drying the applied resin composition to form the resin layer on the support plate. Specific examples of the lamination method include a method of laminating a resin film that will become the resin layer onto the support plate. More specifically, this method includes a method of laminating the resin film laminated on a release film onto the support plate, and then peeling the release film from the resin film. Examples of resin film lamination include vacuum lamination. Examples of the resin film include a resin film formed by applying a fluid resin composition (such as a resin varnish or a resin solution) to a release film and drying the resin composition applied to the release film.

[0156] The support plate is not particularly limited as long as it has an insulating layer (insulating layer with a seed layer formed on its surface) on its surface. Examples of the support include a resin film, a metal foil, a metal plate, a metal-clad laminate, and an inner layer substrate.

[0157] The method for curing the resin layer is not particularly limited as long as it can form an insulating layer. Examples of methods for curing the resin layer include curing in a vacuum, i.e., vacuum curing. If the resin layer is thermosetting, methods such as heating the resin layer can be used. The conditions for curing the resin layer are not particularly limited as long as they can cure the resin layer and form the insulating layer. Examples of such conditions include a heating temperature of preferably 80 to 250°C, more preferably 100 to 230°C. A heating time of preferably 1 to 4 hours, more preferably 1.5 to 3 hours. More specifically, examples of methods for heating the resin layer include heating from room temperature to a predetermined temperature between 80 and 150°C, maintaining the temperature for approximately 30 minutes, further heating to a predetermined temperature between 180 and 230°C, and maintaining the predetermined temperature for 1 to 4 hours. The method for heating the resin layer may also be vacuum curing. Furthermore, examples of a method for curing the resin layer include a method in which, if the resin layer is photocurable, the resin layer is irradiated with light such as ultraviolet light.

[0158] The step (B) is not particularly limited as long as the insulating layer can be roughened by plasma treatment. In step (B), the insulating layer on the support is plasma-treated, and the surface of the insulating layer opposite the surface in contact with the support (the surface not in contact with the support) is plasma-treated. The plasma treatment is not particularly limited, and examples thereof include oxygen gas plasma treatment (surface treatment using plasma generated using oxygen gas as a raw material gas), oxygen and carbon tetrafluoride mixed gas plasma treatment (surface treatment using plasma generated using oxygen and carbon tetrafluoride mixed gas as a raw material gas), and argon, hydrogen, and nitrogen mixed gas plasma treatment (surface treatment using plasma generated using argon, hydrogen, and nitrogen mixed gas as a raw material gas). Among these, oxygen gas plasma treatment is preferred as the plasma treatment. These plasma treatments may be used alone or in combination of two or more.

[0159] The conditions for the plasma treatment are not particularly limited. The plasma irradiation amount in the plasma treatment is 100 to 500 W / cm in watt density. ２ The time for which the plasma treatment is carried out varies depending on the amount of raw material gas, the plasma density, etc., but is preferably 0.5 to 5 minutes, for example.

[0160] The plasma treatment may be a treatment using microwave plasma (plasma excited by microwaves) or RF (Radio Frequency) plasma (plasma excited by RF). These plasmas may be pulse-excited or DC-excited. The microwaves may be, for example, microwaves with a frequency of 1 GHz or higher, which is an industrially usable frequency band and capable of generating high-density non-equilibrium plasma. Microwaves with a frequency of 2.45 GHz are preferred. In the case of microwave plasma, the microwave power used to generate the plasma atmosphere may be, for example, 300 W or higher. RF plasma is widely used in industry, and the excitation frequency used to generate RF plasma is generally 13.56 MHz in Japan due to legal regulations.

[0161] The step (C) is not particularly limited as long as a seed layer can be formed on the roughened surface of the insulating layer by sputtering. The sputtering treatment is not particularly limited as long as the seed layer can be formed on the roughened surface of the insulating layer.

[0162] Examples of the sputtering process include sputtering processes using the metal constituting the seed layer as a target. Examples of the sputtering process include sputtering processes performed under vacuum. Specifically, examples of the sputtering process include placing the metal constituting the seed layer as a target in a vacuum chamber, applying a high voltage to ionize the gas, causing it to collide with the target, and causing metal atoms to separate from the target surface and adhere to the roughened surface of the insulating layer to form a film. Examples of the gas include rare gases such as argon and nitrogen. Examples of the sputtering process include direct current (DC) sputtering, radio frequency (RF) sputtering, DC magnetron sputtering, RF magnetron sputtering, and ion beam sputtering.

[0163] The seed layer is not particularly limited as long as it is formed on the surface of an insulating layer or the like during the manufacture of a wiring board. For example, the seed layer is used as an electrode when a conductor wiring pattern and a conductor layer are subsequently formed by electroplating or the like. That is, the seed layer acts as a power supply layer for the subsequent electroplating process. Examples of metals contained in the seed layer include titanium (Ti), chromium (Cr), nickel (Ni), tungsten (W), copper (Cu), cobalt (Co), aluminum (Al), molybdenum (Mo), tantalum (Ta), iridium (Ir), ruthenium (Ru), lead (Pb), gold (Au), and platinum (Pt). Among these, Ti, Cr, Ni, and W are preferred. These metals may be used alone or in combination. That is, the seed layer preferably contains at least one metal selected from the group consisting of Ti, Cr, Ni, and W. The seed layer may also include a seed layer main body and a seed adhesion layer that improves adhesion of the seed layer main body to the insulating layer, etc. Examples of the seed layer include a layer obtained by stacking a Ti-containing layer (e.g., a layer made of Ti) as the seed adhesion layer and a Cu-containing layer (e.g., a layer made of Cu) as the seed layer main body. Examples of the thickness of the seed layer include 200 to 350 nm. When the seed layer includes the seed layer main body and the seed adhesion layer, examples of the thickness of the seed layer main body include 150 to 250 nm, and examples of the thickness of the seed adhesion layer include 50 to 100 nm.

[0164] As described above, the manufacturing method may be such that a conductor wiring pattern is formed based on the seed layer, and specifically, may further include a step (D) of forming a conductor wiring pattern on the seed layer. This step (D) is not particularly limited as long as a conductor wiring pattern can be formed using the seed layer, and examples thereof include a method of forming a wiring layer by electroplating or the like. Examples of electroplating include electrolytic nickel plating, electrolytic copper plating, electrolytic chromium plating, electrolytic palladium plating, electrolytic gold plating, electrolytic rhodium plating, and electrolytic iridium plating, and among these, electrolytic copper plating is preferred.

[0165] As described above, the manufacturing method uses a layer containing a cured product of the resin composition (e.g., a layer made of a cured product of the resin composition) as the insulating layer. Therefore, this manufacturing method is a method for manufacturing a wiring board using a cured product of the resin composition. As described above, the cured product of the resin composition has a surface roughness Ra of less than 100 nm before the plasma treatment. Even after the cured product is subjected to the plasma treatment, the cured product of the resin composition can maintain a low surface roughness Ra, for example, less than 100 nm. Furthermore, the cured product of the resin composition has a low relative dielectric constant of less than 2.6 at 10 GHz. These factors can reduce signal transmission loss in the conductor wiring pattern formed based on the seed layer. Specifically, signal transmission loss in the conductor wiring (conductor circuit) of the conductor wiring pattern formed by performing step (D) can be reduced.

[0166] As described above, this specification discloses various aspects of the technology, the main technologies of which are summarized below.

[0167] The cured product of the resin composition according to a first aspect of the present invention is a cured product of a resin composition, wherein the resin composition contains a filler, the filler has a 50% particle size D50 in a volume-based cumulative particle size distribution of 2100 nm or less, the content of the filler is less than 35 mass% with respect to the resin composition, the cured product has a relative dielectric constant at 10 GHz of less than 2.6, and the cured product has a surface roughness Ra of less than 100 nm.

[0168] A cured product of the resin composition according to a second aspect of the present invention is the cured product of the resin composition according to the first aspect of the present invention, wherein the filler has a 50% particle size D50 in a volume-based cumulative particle size distribution of 100 to 700 nm.

[0169] The cured product of the resin composition related to the third aspect of the present invention is the cured product of the resin composition related to the first or second aspect of the present invention, and has a thermal expansion coefficient of less than 80 ppm / °C.

[0170] A cured product of a resin composition according to a fourth aspect of the present invention is the cured product of the resin composition according to any one of the first to third aspects of the present invention, wherein the resin composition further contains an elastomer, and the content of the elastomer is more than 10 mass% with respect to the resin composition.

[0171] A resin composition according to a fifth aspect of the present invention is the resin composition according to any one of the first to fourth aspects of the present invention, wherein the filler comprises at least one selected from the group consisting of polystyrene particles, hollow polystyrene particles, inorganic particles, and hollow inorganic particles.

[0172] A wiring board according to a sixth aspect of the present invention is a wiring board comprising an insulating layer containing a cured product of the resin composition according to any one of the first to fifth aspects of the present invention, and wiring.

[0173] A semiconductor package according to a seventh aspect of the present invention is a semiconductor package comprising the wiring board according to the sixth aspect of the present invention and a semiconductor chip mounted on the wiring board.

[0174] According to the present invention, it is possible to provide a cured product of a resin composition having low dielectric properties such as a dielectric constant and low surface roughness after plasma treatment. Furthermore, according to the present invention, it is possible to provide a wiring board and a semiconductor package obtained using the cured product of the resin composition.

[0175] The present invention will be explained in more detail below with reference to examples, but the scope of the present invention is not limited to these examples.

[0176] Examples 1 to 3 and Comparative Example 1 In these examples, each component used in preparing the resin composition will be described.

[0177] (Elastomers) Elastomer 1: Styrene butadiene styrene copolymer (liquid 1,2-SBS manufactured by Nippon Soda Co., Ltd.) Elastomer 2: Partially hydrogenated styrene (ethylene / butylene) styrene copolymer (Tuftec P1500 manufactured by Asahi Kasei Corporation) Elastomer 3: Hydrogenated styrene (ethylene / butylene) styrene copolymer (Tuftec H1221 manufactured by Asahi Kasei Corporation)

[0178] (Curable Compound) PPE: Modified polyphenylene ether compound (modified polyphenylene ether in which the terminal hydroxyl groups of polyphenylene ether are modified with methacrylic groups, SA9000 manufactured by SABIC Innovative Plastics, number average molecular weight Mn 2300)

[0179] (Curing agent) TAIC: triallyl isocyanurate (TAIC manufactured by Nippon Kasei Chemical Co., Ltd.)

[0180] (Reaction initiator) PBP: α,α'-bis(t-butylperoxy-m-isopropyl)benzene (Perbutyl P (PBP) manufactured by NOF Corporation) 2E4MZ: 2-ethyl-4-methylimidazole (2E4MZ manufactured by Shikoku Chemicals Corporation)

[0181] (Other Components) Epoxidized PB: epoxidized polybutadiene (JP-100 manufactured by Nippon Soda Co., Ltd.) Flame retardant: phosphine oxide flame retardant (paraxylylenebisdiphenylphosphine oxide, PQ60 manufactured by Shinichi Chemical Co., Ltd.)

[0182] (Fillers) Silica particles 1: Silica particles with a D50 of 180 nm (K180SV-C1 manufactured by Admatechs Co., Ltd.) Silica particles 2: Silica particles with a D50 of 500 nm (SC2300-SVJ manufactured by Admatechs Co., Ltd.) Hollow silica particles 1: Hollow silica particles with a D50 of 2000 nm (HS200 manufactured by AGC Si-Tech Co., Ltd., specific gravity 0.46) Hollow silica particles 2: Silica particles with a D50 of 580 nm (hollow silica manufactured by Admatechs Co., Ltd., specific gravity 1.4)

[0183] (Production of Evaluation Substrate) First, a resin composition was prepared to have the composition (parts by mass) shown in Table 1. The filler content relative to the resin composition was 28.5% by mass in Example 1, 12.7% by mass in Example 2, 29.5% by mass in Example 3, and 37.3% by mass in the comparative example. Using this resin composition, an evaluation substrate was produced by the method shown in FIG. 1 , in which a conductor layer was formed on an insulating layer made of a cured product of the resin composition. Specifically, a layer made of the resin composition was used as the resin layer 12, and the substrate was heated from room temperature to 130°C, held at that temperature for 30 minutes, then heated to 220°C and held at that temperature for 2 hours to cure the resin layer 12, thereby obtaining the insulating layer 14. That is, the insulating layer 14 was a layer made of a cured product of the resin composition. Furthermore, the plasma treatment was performed using oxygen gas plasma treatment. The sputtering process was a process in which a 50 to 100 nm Ti layer was formed as the seed adhesion layer, and a 150 to 250 nm Cu layer was formed as the seed layer main body, followed by an electrolytic plating process to form a 15 to 35 μm Cu layer as the conductor layer.

[0184] [Dielectric Properties (Dielectric Constant Dk and Dielectric Loss Tangent Df)] The dielectric constant and dielectric loss tangent of the insulating layer (cured product of the resin composition) at 10 GHz were measured by a cavity resonator perturbation method. Specifically, the dielectric constant (Dk) and dielectric loss tangent (Df) of the insulating layer at 10 GHz were measured using a network analyzer (N5230A manufactured by Keysight Technologies, Inc.).

[0185] [Storage Modulus] The insulating layer (cured product of the resin composition) was cut into a size of 10 mm x 40 mm and attached to a dynamic viscoelasticity measuring device (DMS6100 manufactured by Seiko Instruments Inc.) A test was performed at a strain amplitude of 10 μm, a frequency of 10 Hz (sine wave), and a temperature rise rate of 5° C. / min, and the storage modulus (MPa) at 40° C. was measured.

[0186] [Coefficient of Thermal Expansion] The insulating layer (cured product of the resin composition) was used as a test piece, and the coefficient of thermal expansion (CTE: ppm / °C) in the Y-axis direction was measured by the TMA method (thermo-mechanical analysis) in accordance with JIS C 6481. For the measurement, a TMA device (TMA6000 manufactured by SII NanoTechnology Inc.) was used, and measurements were performed in the range of 50 to 100°C.

[0187] [Surface Roughness Ra Before Plasma Treatment] The surface roughness Ra of the insulating layer (the cured product of the resin composition) before plasma treatment was measured by surface roughness analysis using a scanning confocal laser microscope (LEXT OLS3000 manufactured by Olympus Corporation).

[0188] [Surface Roughness Ra After Plasma Treatment] The surface roughness Ra of the insulating layer (cured product of the resin composition) after plasma treatment was measured by surface roughness analysis using a scanning confocal laser microscope (LEXT OLS3000 manufactured by Olympus Corporation).

[0189] These results are shown in Table 1 together with the formulation of the resin composition.

[0190] From Table 1, it was found that when a cured product of a resin composition containing a filler having a 50% particle size D50 in a volume-based cumulative particle size distribution of 2100 nm or less and having a content of less than 35 mass %, and when the relative dielectric constant of the cured product at 10 GHz is less than 2.6 and the surface roughness Ra of the cured product is less than 100 nm (0.1 μm) (Examples 1 to 3), the cured product has lower dielectric properties such as relative dielectric constant and lower surface roughness after plasma treatment compared to when this is not the case (Comparative Example).

[0191] This application is based on Japanese Patent Application No. 2023-201907 filed on November 29, 2023, the contents of which are incorporated herein by reference.

[0192] In order to express the present invention, the present invention has been properly and sufficiently described through the embodiments in the above, but it should be recognized that those skilled in the art can easily change and / or improve the above-mentioned embodiments. Therefore, unless the changes or improvements made by those skilled in the art are at a level that causes departure from the scope of the claims described in the claims, such changes or improvements are interpreted as being included in the scope of the claims.

[0193] According to the present invention, there is provided a cured product of a resin composition having low dielectric properties such as a dielectric constant and low surface roughness after plasma treatment. Also, according to the present invention, there are provided a wiring board and a semiconductor package obtained using the cured product of the resin composition.

Claims

1. A cured product of a resin composition, the resin composition comprising a filler, the filler having a 50% particle diameter D50 in a volume-based cumulative particle diameter distribution of 2100 nm or less, the content of the filler being less than 35 mass% relative to the resin composition, the cured product having a relative dielectric constant of less than 2.6 at 10 GHz, and the cured product having a surface roughness Ra of less than 100 nm.

2. A cured product of the resin composition according to claim 1, wherein the filler has a 50% particle size D50 in a cumulative particle size distribution on a volume basis of 100 to 700 nm.

3. A cured product of the resin composition according to claim 1, having a thermal expansion coefficient of less than 80 ppm / °C.

4. The cured product of the resin composition according to claim 1, wherein the resin composition further contains an elastomer, and the content of the elastomer is more than 10 mass% based on the resin composition.

5. A cured product of the resin composition according to claim 1, wherein the filler comprises at least one selected from the group consisting of polystyrene particles, hollow polystyrene particles, inorganic particles, and hollow inorganic particles.

6. A wiring board comprising an insulating layer containing a cured product of the resin composition according to any one of claims 1 to 5, and wiring.

7. A semiconductor package comprising the wiring board according to claim 6 and a semiconductor chip mounted on said wiring board.