Resin composition

Abstract

To provide a resin composition enabling acquisition of a cured product which has low dielectric loss tangent and has low average coefficient of linear thermal expansion, and is excellent in adhesion to a conductor layer after tested in an HAST manner.SOLUTION: A resin composition is provided, including (A) a silane coupling agent having a radical reactive functional group, (B) one or more polystyrene materials selected from the group consisting of a polystyrene resin having a weight average molecular weight of 1,000 to 100,000, and polystyrene particles having an average particle diameter of 3 μm or less, (C) a radical reactive resin, and (D) an inorganic filler, wherein the amount of the component (D) is 70 mass% or more with respect to 100 mass% of a non-volatile component in the resin composition.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a resin composition, a method for producing the same, a resin sheet, a cured product, a circuit board, and a semiconductor device. [Background technology]

[0002] Circuit boards such as printed wiring boards are widely used in various electronic devices. A known method for manufacturing circuit boards is a build-up method in which insulating layers and conductor layers are alternately stacked on an inner layer substrate. The insulating layer is formed, for example, from a cured product of a resin composition (Patent Documents 1 to 3). Specific examples include forming a resin composition layer containing a resin composition and curing the resin composition layer to form an insulating layer containing a cured product of the resin composition. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4325337 [Patent Document 2] International Publication No. 2022 / 025123 [Patent Document 3] Japanese Patent Publication No. 2020-128501 Summary of the Invention [Problem to be solved by the invention]

[0004]

[0003] An insulating layer is required to have a low dielectric loss tangent and a low coefficient of linear thermal expansion. Therefore, the present inventors have investigated a resin composition containing a radical-reactive resin and an inorganic filler. However, it has been found that when the amount of inorganic filler is increased to significantly reduce the coefficient of linear thermal expansion of a cured product of a resin composition containing a radical-reactive resin and an inorganic filler, the adhesiveness to the conductor layer, which corresponds to the base of the insulating layer, is reduced.

[0005] Specifically, the following applies. Generally, an insulating layer may be formed so as to bond to a conductor layer. For example, an insulating layer may be formed from a cured resin composition on a substrate having conductor layers such as electrodes and wiring formed on its surface. To improve the reliability of a circuit board, high adhesion between the insulating layer and the conductor layer is desirable. In particular, from the perspective of achieving high reliability over a long period of time and extending the life of the circuit board, it is desirable for the adhesion between the insulating layer and the conductor layer to be excellent after HAST (High Accelerated Stress Test). However, it has been found that a cured resin composition containing a combination of a radical-reactive resin and a large amount of inorganic filler has poor adhesion between the insulating layer and the conductor layer, and the adhesion after HAST is particularly significantly poor.

[0006] The present invention has been made in view of the above-mentioned problems, and aims to provide a resin composition and a method for producing the same that can give a cured product that has a low dielectric loss tangent and a low mean linear thermal expansion coefficient and that has excellent adhesion to a conductor layer after HAST; a resin sheet containing the resin composition; a cured product of the resin composition; and a circuit board and a semiconductor device that contain the cured product. [Means for solving the problem]

[0007] The present inventors have conducted extensive research to solve the above-mentioned problems, and as a result, have found that the above-mentioned problems can be solved by a resin composition containing (A) a silane coupling agent having a radical-reactive functional group, (B) one or more polystyrene materials selected from the group consisting of polystyrene resins having a weight-average molecular weight within a specific range and polystyrene particles having an average particle size within a specific range, (C) a radical-reactive resin, and (D) an inorganic filler in an amount within a specific range, and have completed the present invention. That is, the present invention includes the following.

[0008] <1> (A) a silane coupling agent having a radical-reactive functional group; (B) one or more polystyrene materials selected from the group consisting of polystyrene resins having a weight-average molecular weight of 1,000 to 100,000 and polystyrene particles having an average particle diameter of 3 μm or less; (C) a radical reactive resin, and (D) an inorganic filler; A resin composition, wherein the amount of component (D) is 70% by mass or more relative to 100% by mass of the nonvolatile components in the resin composition. <2> The amount of the (A) component is 0.01% by mass or more and 5% by mass or less based on 100% by mass of the nonvolatile components in the resin composition. <1> The resin composition according to claim 1. <3> The component (D) contains (D-1) an inorganic filler that has been surface-treated with the component (A). <1> or <2> The resin composition according to claim 1. <4> the amount of the surface treatment of the component (D-1) with the component (A) is 0.1% by mass or more and 3.0% by mass or less; <3> The resin composition according to claim 1. <5> The amount of the (B) component is 0.1% by mass or more and 40% by mass or less, relative to 100% by mass of the resin component in the resin composition. <1> ~ <4> The resin composition according to any one of claims 1 to 10. <6> The component (C) contains one or more selected from the group consisting of a maleimide resin, a styryl resin, a (meth)acrylic resin, and an allyl resin. <1> ~ <5> The resin composition according to any one of claims 1 to 10. <7> (E) containing a polymer resin; <1> ~ <6> The resin composition according to any one of claims 1 to 10. <8> The amount of the (E) component is 1% by mass or more and 15% by mass or less, based on 100% by mass of the resin component in the resin composition. <7> The resin composition according to claim 1. <9> With or without epoxy resin; The amount of the epoxy resin is 3% by mass or less based on 100% by mass of the nonvolatile components in the resin composition. <1> ~ <8> The resin composition according to any one of claims 1 to 10. <10> Have a minimum melt viscosity of 5,000 poise or less, <1> ~ <9> The resin composition according to any one of claims 1 to 10. <11> For forming insulating layers on circuit boards. <1> ~ <10> The resin composition according to any one of claims 1 to 10. <12> <1> ~ <11> A method for producing the resin composition according to any one of the above items: A method for producing a resin composition, comprising the step of mixing (A) a silane coupling agent having a radical-reactive functional group, (B) one or more polystyrene materials selected from the group consisting of a polystyrene resin having a weight-average molecular weight of 1,000 to 100,000 and polystyrene particles having an average particle diameter of 3 μm or less, (C) a radical-reactive resin, and (D) an inorganic filler. <13> <3> or <4> A method for producing the resin composition according to the present invention; (A) a silane coupling agent having a radical-reactive functional group and (D') an inorganic filler before surface treatment are mixed to obtain (D-1) an inorganic filler surface-treated with component (A); a step of mixing component (D-1), (B) one or more polystyrene materials selected from the group consisting of polystyrene resins having a weight average molecular weight of 1,000 to 100,000 and polystyrene particles having an average particle diameter of 3 μm or less, and (C) a radical reactive resin; A method for producing a resin composition, comprising: <14> A support and a resin composition layer provided on the support, The resin composition layer is <1> ~ <11> A resin sheet comprising the resin composition according to any one of claims 1 to 4. <15> <1> ~ <11> A cured product of the resin composition according to any one of claims 1 to 4. <16> <1> ~ <11> A circuit board comprising a cured product of the resin composition according to any one of claims 1 to 4. <17> <16> A semiconductor device comprising the circuit board according to claim 1. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a resin composition and a method for producing the same that can give a cured product that has a low dielectric loss tangent and a low mean linear thermal expansion coefficient and that has excellent adhesion to a conductor layer after HAST; a resin sheet containing the resin composition; a cured product of the resin composition; and a circuit board and a semiconductor device that contain the cured product. DETAILED DESCRIPTION OF THE INVENTION

[0010] The present invention will be described below with reference to embodiments and examples. However, the present invention is not limited to the embodiments and examples shown below, and may be modified and implemented within the scope of the claims and their equivalents.

[0011] As used herein, the term "optionally substituted" in reference to a compound or group means both a case where the hydrogen atoms of the compound or group are not substituted with substituents, and a case where some or all of the hydrogen atoms of the compound or group are substituted with substituents.

[0012] <Outline of Resin Composition> A resin composition according to one embodiment of the present invention comprises (A) a silane coupling agent having a radical-reactive functional group, (B) one or more polystyrene materials selected from the group consisting of polystyrene resins having a weight-average molecular weight of 1,000 to 100,000 and polystyrene particles having an average particle size of 3 μm or less, (C) a radical-reactive resin, and (D) an inorganic filler, wherein the total amount of the inorganic filler (D) is within a specific range.

[0013] In the following description, "(A) a silane coupling agent having a radical-reactive functional group" may be referred to as "(A) a radical-reactive silane coupling agent." Also, "(B) one or more polystyrene materials selected from the group consisting of polystyrene resins having a weight-average molecular weight of 1,000 to 100,000 and polystyrene particles having an average particle diameter of 3 μm or less" may be referred to as "(B) a specific polystyrene material." Furthermore, "polystyrene resins having a weight-average molecular weight of 1,000 to 100,000" may be referred to as "low-molecular-weight polystyrene resins," and may be designated with the symbol "(B-1)" as needed. Also, "polystyrene particles having an average particle diameter of 3 μm or less" may be referred to as "small-diameter polystyrene particles," and may be designated with the symbol "(B-2)" as needed.

[0014] The resin composition according to this embodiment can form a bond by reacting the (A) radical-reactive silane coupling agent and the (C) radical-reactive resin, and can be cured to form a cured product through this reaction. The reactions can include reactions between the (A) radical-reactive silane coupling agents, reactions between the (C) radical-reactive resins, and reactions between the (A) radical-reactive silane coupling agent and the (C) radical-reactive resin. This cured product has a low dielectric loss tangent and mean linear thermal expansion coefficient and exhibits excellent adhesion to the conductor layer after HAST. Furthermore, this cured product typically exhibits excellent adhesion to the conductor layer not only after HAST but also before HAST. Furthermore, the resin composition according to this embodiment typically exhibits a low minimum melt viscosity.

[0015] The present inventors speculate that the mechanism by which the resin composition according to the present embodiment exhibits the above-described excellent effects is as follows, although the present invention is not limited to the mechanism described below.

[0016] The resin composition according to this embodiment is cured by the reaction of (A) a radical-reactive silane coupling agent and (C) a radical-reactive resin. This reaction is a radical reaction, and does not typically produce polar groups such as hydroxyl groups. Furthermore, (B) the specific polystyrene material is generally a polymer material with low polarity. Therefore, the cured product of the resin composition can have low polarity, thereby reducing the dielectric loss tangent.

[0017] The resin composition according to this embodiment contains a large amount of (D) inorganic filler, and therefore, the cured product of the resin composition also contains a large amount of (D) inorganic filler. In general, the inorganic material contained in (D) inorganic filler has a smaller thermal expansion than organic material. Therefore, the (D) inorganic filler can reduce the thermal expansion of the cured product, thereby reducing the mean linear thermal expansion coefficient of the cured product.

[0018] In the past, silane coupling agents have been added to resin compositions to improve the dispersibility of inorganic particles in the resin composition or to enhance adhesion between the cured resin composition and a conductor. However, conventional silane coupling agents used in insulating layers often contain polar groups such as amino groups, resulting in poor compatibility with the low-polarity radical-reactive resin (C). Therefore, when conventional silane coupling agents are used as surface treatment agents for inorganic particles, the compatibility between the inorganic particles and the resin component containing the radical-reactive resin (C) is poor, leading to the occurrence of fracture of the cured product originating from the interface between the two. Furthermore, when conventional silane coupling agents are mixed with the resin component containing the radical-reactive resin (C), the poor compatibility between the two components results in the formation of a phase interface, which in turn leads to the occurrence of fracture of the cured product originating from the phase interface. This tendency to fracture the cured product has traditionally led to delamination due to the fracture of the cured product. In particular, during HAST, the cured product is placed in a high-temperature, high-humidity environment, which allows water vapor to penetrate the phase interface, accelerating resin deterioration. This makes delamination more likely to occur, and the adhesion between the cured product and the conductor layer tends to decrease significantly.

[0019] In contrast, the radical-reactive silane coupling agent (A) used in the resin composition according to this embodiment generally has low polarity and therefore has excellent compatibility with the radical-reactive resin (C). Furthermore, (B) specific polystyrene materials, such as (B-1) low-molecular-weight polystyrene resins and (B-2) small-diameter polystyrene particles, have excellent compatibility with (C) radical-reactive resins. Specifically, polystyrene resins with too low a molecular weight may aggregate together, resulting in poor compatibility with (C) radical-reactive resins. Furthermore, polystyrene resins with too high a weight-average molecular weight and polystyrene particles with too large a particle size tend to have poor compatibility with (C) radical-reactive resins. In contrast, (B-1) low-molecular-weight polystyrene resins and (B-2) small-diameter polystyrene particles with an appropriate weight-average molecular weight or average particle size have excellent compatibility with (C) radical-reactive resins, thereby suppressing the formation of phase interfaces. Furthermore, (B) specific polystyrene materials generally have flexible molecular skeletons, which can absorb stress and increase the toughness of the cured product. Therefore, according to the resin composition of this embodiment, the mechanical strength of the cured product can be improved while suppressing the formation of the above-mentioned phase interface, thereby suppressing delamination due to destruction of the cured product and improving the adhesion between the cured product and the conductor layer both before and after HAST.

[0020] Furthermore, since the (A) radical-reactive silane coupling agent, the (B) specific polystyrene material, and the (C) radical-reactive resin have excellent compatibility or affinity, the resistance in the resin composition can be reduced, and therefore the resin composition according to this embodiment can usually have a low minimum melt viscosity.

[0021] <(A) Radical reactive silane coupling agent> The resin composition according to this embodiment contains (A) a radical-reactive silane coupling agent as component (A). (A) The radical-reactive silane coupling agent refers to a silane coupling agent having a radical-reactive functional group.

[0022] The radical-reactive functional group typically includes a group containing a non-aromatic carbon-carbon unsaturated bond, such as a non-aromatic carbon-carbon double bond or a non-aromatic carbon-carbon triple bond. Examples of the radical-reactive functional group include unsaturated hydrocarbon groups such as vinyl, allyl, 1-propenyl, 3-cyclohexenyl, 3-cyclopentenyl, 2-vinylphenyl, 3-vinylphenyl, and 4-vinylphenyl; and α,β-unsaturated carbonyl groups such as acryloyl and methacryloyl.

[0023] Typically, (A) the radical-reactive silane coupling agent has a structure in which the radical-reactive functional group is directly or indirectly bonded to a silicon atom. Here, the "direct" bond between the functional group and the silicon atom means that there is no linking group between the functional group and the silicon atom. Furthermore, the "indirect" bond between the functional group and the silicon atom means that there is a linking group between the functional group and the silicon atom.

[0024] The number of radically reactive functional groups contained in one molecule of the (A) radically reactive silane coupling agent may be 1 or 2 or more. Furthermore, when the (A) radically reactive silane coupling agent contains two or more radically reactive functional groups in one molecule, these functional groups may be the same or different. The number of radically reactive functional groups contained in one molecule of the (A) radically reactive silane coupling agent is preferably 1.

[0025] Preferred examples of the radically reactive functional group include groups represented by the following formula (A1).

[0026] [ka]

[0027] (In formula (A1), R 1 represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms; R 2 each independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms; R 3represents a divalent hydrocarbon group; L represents a divalent linking group; m1 and m2 each independently represent 0 or 1; * represents a bonding site.

[0028] In formula (A1), R 1 represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. Examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, an n-pentyl group, a neopentyl group, and an n-hexyl group. 1 is preferably a hydrogen atom or a methyl group.

[0029] In formula (A1), R 2 each independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. Examples of the alkyl group include R 1 Examples of alkyl groups are the same as those given in the above. 2 is preferably a hydrogen atom or a methyl group, more preferably a hydrogen atom.

[0030] In formula (A1), R 3 represents a divalent hydrocarbon group. The divalent hydrocarbon group may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group. The aliphatic hydrocarbon group may be a saturated aliphatic hydrocarbon group or an unsaturated aliphatic hydrocarbon group. Furthermore, the aliphatic hydrocarbon group may be linear, branched, or cyclic. The number of carbon atoms in the divalent hydrocarbon group is usually 1 or more and 20 or less. R 3Examples of the divalent hydrocarbon group include alkylene groups having usually 1 to 20 carbon atoms, preferably 4 to 12 carbon atoms, and more preferably 6 to 8 carbon atoms; cycloalkylene groups having 3 to 20 carbon atoms; alkenylene groups having 2 to 10 carbon atoms; arylene groups having 6 to 10 carbon atoms; and aralkylene groups having 7 to 10 carbon atoms. Specific examples of the divalent hydrocarbon group include alkylene groups such as methylene, ethylene, propylene, trimethylene, tetramethylene, pentamethylene, hexamethylene, heptamethylene, and octamethylene; cycloalkylene groups such as cyclohexylene; alkenylene groups such as vinylene and propenylene; arylene groups such as phenylene, tolylene, xylylene, and naphthylene; and aralkylene groups such as benzylene, phenylethylene, and phenylpropylene. Among these, alkylene groups and arylene groups are preferred; hexamethylene groups, octamethylene groups and phenylene groups are more preferred.

[0031] In formula (A1), L represents a divalent linking group. The divalent linking group preferably contains a heteroatom other than carbon atoms, such as -O-, -CO-, -NHCO-, and -OCO-. Of these, an oxycarbonyl group (-OCO-) is preferred.

[0032] In formula (A1), m1 and m2 each independently represent 0 or 1.

[0033] The silicon atom of the (A) radical-reactive silane coupling agent may have any organic group bonded thereto other than the radical-reactive functional group. Examples of the optional organic group include hydrocarbon groups such as alkyl groups having 1 to 10 carbon atoms and aryl groups having 6 to 10 carbon atoms; hydrocarbonoxy groups such as alkyloxy groups having 1 to 10 carbon atoms and aryloxy groups having 6 to 10 carbon atoms; and acyloxy groups having 1 to 20 carbon atoms. The number of optional organic groups contained in one molecule of the (A) radical-reactive silane coupling agent may be one or two or more. Preferably, the number of optional organic groups contained in one molecule of the (A) radical-reactive silane coupling agent is one to three, and more preferably three.

[0034] A preferred example of the radical reactive silane coupling agent (A) is a compound represented by the following formula (A2).

[0035] [ka]

[0036] (In formula (A2), R 1 represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms; R 2 each independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms; R 3 represents a divalent hydrocarbon group; R 4 each independently represents an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, or an acyl group having 1 to 20 carbon atoms; R 5 each independently represents an alkyl group having 1 to 10 carbon atoms or an aryl group having 6 to 10 carbon atoms; L represents a divalent linking group; m1 and m2 each independently represent 0 or 1; and n represents an integer of 1 to 3.

[0037] In formula (A2), R 4 R each independently represents an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, or an acyl group having 1 to 20 carbon atoms. 4 Specific examples of the alkyl group include linear, branched, or cyclic alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, neopentyl, n-hexyl, n-octyl, and cyclohexyl; aryl groups such as phenyl, tolyl, xylyl, and naphthyl; and acyl groups such as formyl, acetyl, and propionyl. Among these, alkyl groups having 1 to 8 carbon atoms are preferred, alkyl groups having 1 to 6 carbon atoms are more preferred, methyl and ethyl groups are even more preferred, and methyl is particularly preferred.

[0038] In formula (A2), R 5R each independently represents an alkyl group having 1 to 10 carbon atoms or an aryl group having 6 to 10 carbon atoms. 5 Specific examples of include linear, branched, or cyclic alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, neopentyl, n-hexyl, n-octyl, and cyclohexyl; and aryl groups such as phenyl, tolyl, xylyl, and naphthyl. Among these, alkyl groups and phenyl groups having 1 to 8 carbon atoms are preferred; alkyl groups and phenyl groups having 1 to 6 carbon atoms are more preferred; and methyl, ethyl, and phenyl groups are even more preferred.

[0039] In formula (A2), n represents an integer of 1 to 3, preferably 2 or 3, and more preferably 3.

[0040] In formula (A2), R 1 , R 2 , R 3 , L, m1 and m2 are the same as in formula (A1).

[0041] (A) Examples of radical-reactive silane coupling agents include 8-methacryloxyoctyltrimethoxysilane (such as "KBM-5803" manufactured by Shin-Etsu Chemical Co., Ltd.), 7-octenyltrimethoxysilane (such as "KBM-1083" manufactured by Shin-Etsu Chemical Co., Ltd.), p-styryltrimethoxysilane (such as "KBM-1403" manufactured by Shin-Etsu Chemical Co., Ltd.), 3-methacryloxypropyltrimethoxysilane (such as "KBM-503" manufactured by Shin-Etsu Chemical Co., Ltd.), and vinyltrimethoxysilane (such as "KBM-1003" manufactured by Shin-Etsu Chemical Co., Ltd.).

[0042] The (A) radical reactive silane coupling agent may be used alone or in combination of two or more.

[0043] There are no limitations on the state of the (A) radical-reactive silane coupling agent in the resin composition. Therefore, the (A) radical-reactive silane coupling agent may be adsorbed onto the surface of the (D) inorganic filler. Alternatively, the (A) radical-reactive silane coupling agent may be free in the resin component of the resin composition without being adsorbed onto the surface of the (D) inorganic filler. Unless otherwise specified, the "resin component" of the resin composition refers to the non-volatile components in the resin composition excluding the (A) radical-reactive silane coupling agent and the (D) inorganic filler. Unless otherwise specified, the "non-volatile component" of the resin composition refers to the components other than the solvent contained in the resin composition.

[0044] In particular, from the viewpoint of significantly achieving the effects of the present invention, it is preferable that the (A) radical-reactive silane coupling agent is adsorbed on the surface of the (D) inorganic filler. Usually, by subjecting the (D) inorganic filler before treatment with the (A) radical-reactive silane coupling agent to surface treatment with the (A) radical-reactive silane coupling agent, the (A) radical-reactive silane coupling agent is adsorbed on the surface of the (D) inorganic filler. Therefore, by mixing the (D) inorganic filler thus surface-treated with other components, a resin composition containing the (A) radical-reactive silane coupling agent adsorbed on the surface of the (D) inorganic filler can be obtained.

[0045] The amount of (A) radical-reactive silane coupling agent is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and even more preferably 0.2% by mass or more, relative to 100% by mass of the nonvolatile components in the resin composition, and is preferably 5.0% by mass or less, more preferably 2.0% by mass or less, and even more preferably 1.0% by mass or less. When the amount of (A) radical-reactive silane coupling agent is within the above range, the dielectric loss tangent, average coefficient of linear thermal expansion, and adhesion after HAST can be particularly improved, and more usually, the adhesion before HAST and the minimum melt viscosity of the resin composition can be effectively improved.

[0046] The amount of (A) radical-reactive silane coupling agent is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, even more preferably 0.5% by mass or more, and is preferably 10.0% by mass or less, more preferably 6.0% by mass or less, and even more preferably 3.0% by mass or less, relative to 100% by mass of the resin components in the resin composition. When the amount of (A) radical-reactive silane coupling agent is within the above range, the dielectric loss tangent, average coefficient of linear thermal expansion, and adhesion after HAST can be particularly improved, and more usually, the adhesion before HAST and the minimum melt viscosity of the resin composition can be effectively improved.

[0047] The amount of (A) radical-reactive silane coupling agent is preferably 0.1% by mass or more, more preferably 1% by mass or more, and even more preferably 3% by mass or more, relative to 100% by mass of (B) specific polystyrene material, and is preferably 40% by mass or less, more preferably 30% by mass or less, and particularly preferably 20% by mass or less. When the amount of (A) radical-reactive silane coupling agent is within the above range, the dielectric loss tangent, average coefficient of linear thermal expansion, and adhesion after HAST can be particularly improved, and more usually, the adhesion before HAST and the minimum melt viscosity of the resin composition can be effectively improved.

[0048] The amount of the (A) radical-reactive silane coupling agent is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and even more preferably 1.0% by mass or more, relative to 100% by mass of the (C) radical-reactive resin, and is preferably 20% by mass or less, more preferably 10% by mass or less, and even more preferably 5% by mass or less. When the amount of the (A) radical-reactive silane coupling agent is within the above range, the dielectric loss tangent, the average coefficient of linear thermal expansion, and the adhesion after HAST can be particularly improved, and more usually, the adhesion before HAST and the minimum melt viscosity of the resin composition can be effectively improved.

[0049] The amount of the (A) radical-reactive silane coupling agent is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, even more preferably 0.2% by mass or more, and preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 2% by mass or less, based on 100% by mass of the (D) inorganic filler. The amount of the (D) inorganic filler includes the amount of the (A) radical-reactive silane coupling agent and any surface treatment agent, such as a surface treatment agent, adsorbed to the particles of the (D) inorganic filler by surface treatment, unless otherwise specified. When the amount of the (A) radical-reactive silane coupling agent is within the above range, the dielectric loss tangent, mean coefficient of linear thermal expansion, and adhesion after HAST can be particularly improved, and typically, adhesion before HAST and the minimum melt viscosity of the resin composition can be effectively improved.

[0050] <(B) Specific polystyrene materials> The resin composition according to this embodiment includes a specific polystyrene material (B) as component (B). The specific polystyrene material (B) is selected from the group consisting of a low-molecular-weight polystyrene resin (B-1) and small-diameter polystyrene particles (B-2). The specific polystyrene material (B) does not include the above-mentioned component (A), unless otherwise specified. Typically, the low-molecular-weight polystyrene resin (B-1) is included in the resin composition in a state compatible with the resin components in the resin composition, and is included in the cured product in this compatible state. On the other hand, the small-diameter polystyrene particles (B-2) are not compatible with the resin components in the resin composition, and are included in the resin composition in a particulate state, and are included in the cured product in this particulate state.

[0051] The (B-1) low-molecular-weight polystyrene resin refers to a polystyrene resin having a weight-average molecular weight within a specific range. The weight-average molecular weight of the (B-1) low-molecular-weight polystyrene resin is typically 1,000 or more, preferably 5,000 or more, more preferably 8,000 or more, and typically 100,000 or less, more preferably 80,000 or less, and even more preferably 60,000 or less. The (B-1) low-molecular-weight polystyrene resin having a weight-average molecular weight within this range exhibits excellent compatibility with the (A) radical-reactive silane coupling agent and the (C) radical-reactive resin. This improves the mean linear thermal expansion coefficient of the cured product of the resin composition and the adhesion after HAST, and typically also improves the adhesion before HAST and the minimum melt viscosity of the resin composition.

[0052] The weight-average molecular weight of a resin such as (B-1) low-molecular-weight polystyrene resin can be measured as a polystyrene-equivalent value by gel permeation chromatography (GPC). Specifically, the polystyrene-equivalent weight-average molecular weight of the resin can be measured at a column temperature of 40°C using a Shimadzu LC-9A / RID-6A measuring device, a Showa Denko Shodex K-800P / K-804L / K-804L column, and chloroform or the like as a mobile phase, and calculated using a calibration curve of standard polystyrene.

[0053] The (B-1) low-molecular-weight polystyrene resin is generally polystyrene as a polymer of styrene, and therefore contains styrene units. Here, the styrene unit refers to a repeating unit having a structure formed by polymerizing styrene. The proportion of styrene units contained in 100% by mass of the (B-1) low-molecular-weight polystyrene resin is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, even more preferably 80% by mass or more, and even more preferably 90% by mass or more, and is usually 100% by mass or less. When the proportion of styrene units is within the above range, the dielectric loss tangent, average coefficient of linear thermal expansion, and adhesion after HAST can be particularly improved, and more usually, the adhesion before HAST and the minimum melt viscosity of the resin composition can be effectively improved.

[0054] The (B-1) low-molecular-weight polystyrene resin may be a homopolymer of styrene or a copolymer of styrene and an optional monomer. Therefore, the (B-1) low-molecular-weight polystyrene resin may contain an optional copolymerized unit in combination with the styrene unit. The optional copolymerized unit represents a structural unit other than the styrene unit contained in the (B-1) low-molecular-weight polystyrene resin, and corresponds to a structural unit formed by polymerization of an optional monomer. The optional structural unit may be one type or two or more types.

[0055] The (B-1) low-molecular-weight polystyrene resin preferably has a reactive group. The reactive group that the (B-1) low-molecular-weight polystyrene resin may have refers to a group that can undergo a reaction to form a bond when the resin composition is cured. When the (B-1) low-molecular-weight polystyrene resin containing a reactive group is used, the crosslink density of the cured product of the resin composition can be increased, thereby increasing the mechanical strength of the cured product. Therefore, the adhesion between the cured product and the conductor layer can be more effectively improved before and after HAST.

[0056] Examples of the reactive group include an oxazoline group, an acid anhydride group, and a radically reactive functional group. Among these, radically reactive functional groups are preferred from the viewpoint of lowering the minimum melt viscosity of the resin composition. Examples of the radically reactive functional group include the same radically reactive functional groups as those of the radically reactive silane coupling agent (A). Among these, vinylphenyl groups such as 2-vinylphenyl, 3-vinylphenyl, and 4-vinylphenyl groups, and α,β-unsaturated carbonyl groups are preferred; vinylphenyl groups and acryloyl groups are more preferred. One type of reactive group may be used alone, or two or more types may be used in combination.

[0057] Since the (B-1) low-molecular-weight polystyrene resin may have a reactive group, the (B-1) low-molecular-weight polystyrene resin may contain any copolymer unit having a reactive group. The (B-1) low-molecular-weight polystyrene resin containing any copolymer unit having a reactive group can be produced, for example, by a method including copolymerizing styrene with any monomer having a reactive group. The proportion of the any copolymer unit having a reactive group contained in 100% by mass of the (B-1) low-molecular-weight polystyrene resin is preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 20% by mass or more, and preferably 50% by mass or less, more preferably 40% by mass or less, even more preferably 30% by mass or more.

[0058] (B-2) small-diameter polystyrene particles refer to polystyrene resin particles having an average particle size within a specific range. The average particle size of the (B-2) small-diameter polystyrene particles is typically 3 μm or less, preferably 2 μm or less, and more preferably 1 μm or less. The lower limit is preferably 0.01 μm or more, more preferably 0.05 μm or more, and even more preferably 0.1 μm or more. (B-2) small-diameter polystyrene particles having an average particle size within this range have excellent compatibility with (A) the radical-reactive silane coupling agent and (C) the radical-reactive resin, and therefore can be dispersed in the resin component with high dispersibility. This can improve the mean linear thermal expansion coefficient of the cured resin composition and the adhesion after HAST, and also generally improve the adhesion before HAST and the minimum melt viscosity of the resin composition. The average particle size of the (B-2) small-diameter polystyrene particles can be measured using a laser diffraction particle size distribution analyzer (e.g., Shimadzu Corporation's "SALD-2100"). The volume-average particle size can be measured as the average particle size of the (B-2) small-diameter polystyrene particles using the above-mentioned measuring device. The measurement can be performed by dispersing the (B-2) small-diameter polystyrene particles in an organic solvent that does not dissolve the (B-2) small-diameter polystyrene particles. As the organic solvent, a low-polarity or medium-polarity solvent is usually used, preferably toluene or tetrahydrofuran (THF), to prevent aggregation of the (B-2) small-diameter polystyrene particles.

[0059] The (B-2) small-diameter polystyrene particles are polystyrene resin particles, and therefore may contain polystyrene resin or only polystyrene resin. The polystyrene resin contained in the (B-2) small-diameter polystyrene particles may be the same as the (B-1) low-molecular-weight polystyrene resin described above, except that it does not have to have a weight-average molecular weight within a specific range.

[0060] The weight-average molecular weight range of the polystyrene resin contained in the (B-2) small-diameter polystyrene particles may be the same as or different from the weight-average molecular weight range of the (B-1) low-molecular-weight polystyrene resin, but is usually larger than the weight-average molecular weight of the (B-1) low-molecular-weight polystyrene resin. The specific weight-average molecular weight range of the polystyrene resin contained in the (B-2) small-diameter polystyrene particles is preferably 10,000 or more, more preferably 30,000 or more, even more preferably 50,000 or more, and preferably 1,000,000 or less, more preferably 800,000 or less, even more preferably 600,000 or less. The weight-average molecular weight can be measured as a polystyrene-equivalent value by gel permeation chromatography (GPC).

[0061] The (B) specific polystyrene material may contain only (B-1) low-molecular-weight polystyrene resin, only (B-2) small-diameter polystyrene particles, or a combination of (B-1) low-molecular-weight polystyrene resin and (B-2) small-diameter polystyrene particles. The (B) specific polystyrene material may be used singly or in combination of two or more. From the viewpoint of obtaining a cured product with a particularly low dielectric loss tangent and average linear thermal expansion coefficient, it is preferred that the (B) specific polystyrene material contain (B-1) low-molecular-weight polystyrene resin.

[0062] The amount of the (B) specific polystyrene material is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, even more preferably 1% by mass or more, and particularly preferably 2.2% by mass or more, relative to 100% by mass of the nonvolatile components in the resin composition, and is preferably 10% by mass or less, more preferably 8% by mass or less, and particularly preferably 5% by mass or less. When the amount of the (B) specific polystyrene material is within the above range, the dielectric loss tangent, the average coefficient of linear thermal expansion, and the adhesion after HAST can be particularly improved, and more usually, the adhesion before HAST and the minimum melt viscosity of the resin composition can be effectively improved.

[0063] The amount of the (B) specific polystyrene material is preferably 0.1% by mass or more, more preferably 1% by mass or more, even more preferably 4% by mass or more, and particularly preferably 8% by mass or more, relative to 100% by mass of the resin components in the resin composition, and is preferably 40% by mass or less, more preferably 30% by mass or less, even more preferably 20% by mass or less, and particularly preferably 16% by mass or less. When the amount of the (B) specific polystyrene material is within the above range, the dielectric loss tangent, average coefficient of linear thermal expansion, and adhesion after HAST can be particularly improved, and more usually, the adhesion before HAST and the minimum melt viscosity of the resin composition can be effectively improved.

[0064] The amount of the (B) specific polystyrene material is preferably 1% by mass or more, more preferably 5% by mass or more, even more preferably 10% by mass or more, and particularly preferably 12% by mass or more, relative to 100% by mass of the (C) radical-reactive resin in the resin composition, and is preferably 80% by mass or less, more preferably 60% by mass or less, even more preferably 40% by mass or less, and particularly preferably 30% by mass or less. When the amount of the (B) specific polystyrene material is within the above range, the dielectric loss tangent, average coefficient of linear thermal expansion, and adhesion after HAST can be particularly improved, and more usually, the adhesion before HAST and the minimum melt viscosity of the resin composition can be effectively improved.

[0065] The amount of the (B) specific polystyrene material is preferably 0.1% by mass or more, more preferably 1% by mass or more, even more preferably 2% by mass or more, and particularly preferably 3% by mass or more, relative to 100% by mass of the total (D) inorganic filler in the resin composition. It is preferably 30% by mass or less, more preferably 20% by mass or less, even more preferably 10% by mass or less, and particularly preferably 7% by mass or less. As described above, the amount of the (D) inorganic filler includes the amount of the (A) radical-reactive silane coupling agent and any surface treatment agent adsorbed to the particles of the (D) inorganic filler by surface treatment. When the amount of the (B) specific polystyrene material is within the above range, the dielectric loss tangent, mean coefficient of linear thermal expansion, and adhesion after HAST can be particularly improved. Furthermore, the adhesion before HAST and the minimum melt viscosity of the resin composition can usually be effectively improved.

[0066] <(C) Radical reactive resin> The resin composition according to this embodiment contains a radical-reactive resin (C) as component (C). Unless otherwise specified, the radical-reactive resin (C) does not include those corresponding to the above-mentioned components (A) and (B). Because the radical-reactive resin (C) reacts with heat to form bonds, the resin composition can be thermally cured to form a cured product.

[0067] The (C) radical-reactive resin generally contains a radical-reactive unsaturated group. This radical-reactive unsaturated group refers to a group containing an unsaturated bond exhibiting radical reactivity. Examples of this radical-reactive unsaturated group include groups containing non-aromatic carbon-carbon unsaturated bonds. Examples of the radical-reactive unsaturated group include unsaturated hydrocarbon groups such as vinyl, allyl, 1-propenyl, 3-cyclohexenyl, 3-cyclopentenyl, 2-vinylphenyl, 3-vinylphenyl, and 4-vinylphenyl; and α,β-unsaturated carbonyl groups such as acryloyl, methacryloyl, and maleimide (2,5-dihydro-2,5-dioxo-1H-pyrrol-1-yl) groups. The number of radical-reactive unsaturated groups contained in the (C) radical-reactive resin is usually one or more, preferably two or more. When the (C) radical-reactive resin contains two or more radical-reactive unsaturated groups, these two or more radical-reactive unsaturated groups may be the same or different.

[0068] Preferred examples of the (C) radical-reactive resin include maleimide resins, styryl resins, (meth)acrylic resins, and allyl resins. Therefore, the (C) radical-reactive resin preferably contains one or more selected from the group consisting of maleimide resins, styryl resins, (meth)acrylic resins, and allyl resins. Among these, from the viewpoint of significantly achieving the effects of the present invention, maleimide resins and styryl resins are more preferred as the (C) radical-reactive resin.

[0069] The maleimide resin refers to a resin having one or more, preferably two or more, maleimide groups (2,5-dihydro-2,5-dioxo-1H-pyrrol-1-yl groups) per molecule. The maleimide resin may be an aromatic maleimide resin having a maleimide group directly bonded to an aromatic ring, or an aliphatic maleimide resin having no maleimide group directly bonded to an aromatic ring. Among these, the maleimide resin preferably includes an aromatic maleimide resin.

[0070] Commercially available maleimide resins include, for example, dimer diamine structure-containing maleimide resins such as "SLK-2600" and "SLK-6895-T90" (resins represented by the following formula (c-1)) manufactured by Shin-Etsu Chemical Co., Ltd.; dimer diamine structure-containing maleimide resins such as "BMI-1500," "BMI-1700," "BMI-3000J," "BMI-689," and "BMI-2500" manufactured by Designer Molecules Inc.; Examples of the aromatic maleimide resin include "BMI-6100" manufactured by Nippon Kayaku Co., Ltd.; "MIR-5000-60T" (a resin of formula (c-2) below), "MIR-3000-70MT," and "MIR-3000-70T" manufactured by Nippon Kayaku Co., Ltd.; "BMI-70" and "BMI-80" manufactured by K.I. Chemical Industry Co., Ltd.; and "BMI-2300" and "BMI-TMH" manufactured by Daiwa Chemical Industry Co., Ltd. In addition, the maleimide resin (indan ring skeleton-containing maleimide compound) disclosed in the Japan Institute of Invention and Innovation's Disclosure Technical Bulletin No. 2020-500211 may also be used.

[0071] [ka]

[0072] (In the above formula, c1 represents an integer of 1 or more.)

[0073] The amount of maleimide resin is preferably 1% by mass or more, more preferably 5% by mass or more, and even more preferably 10% by mass or more, relative to 100% by mass of the nonvolatile components in the resin composition, and is preferably 25% by mass or less, more preferably 20% by mass or less, and even more preferably 15% by mass or less. When the amount of maleimide resin is within the above range, the dielectric loss tangent, the average coefficient of linear thermal expansion, and the adhesion after HAST can be particularly improved, and more usually, the adhesion before HAST and the minimum melt viscosity of the resin composition can be effectively improved.

[0074] The amount of maleimide resin is preferably 20% by mass or more, more preferably 30% by mass or more, even more preferably 40% by mass or more, particularly preferably 45% by mass or more, and is preferably 80% by mass or less, more preferably 70% by mass or less, even more preferably 60% by mass or less, particularly preferably 54% by mass or less, relative to 100% by mass of the resin components in the resin composition. When the amount of maleimide resin is within the above range, the dielectric loss tangent, average coefficient of linear thermal expansion, and adhesion after HAST can be particularly improved, and more usually, the adhesion before HAST and the minimum melt viscosity of the resin composition can be effectively improved.

[0075] The styryl resin refers to a resin having one or more, preferably two or more, styryl groups or vinyl groups directly bonded to aromatic carbon atoms per molecule. Examples of the styryl resin include low-molecular-weight (molecular-weight less than 1000) styryl resins such as divinylbenzene, 2,4-divinyltoluene, 2,6-divinylnaphthalene, 1,4-divinylnaphthalene, 4,4'-divinylbiphenyl, 1,2-bis(4-vinylphenyl)ethane, 2,2-bis(4-vinylphenyl)propane, and bis(4-vinylphenyl)ether; and high-molecular-weight (molecular-weight 1000 or more) styryl resins such as vinylbenzyl-modified polyphenylene ether resins and styrene-divinylbenzene copolymers. Examples of commercially available styryl resins include "ODV-XET(X03)", "ODV-XET(X04)", and "ODV-XET(X05)" (styrene-divinylbenzene copolymers) manufactured by Nippon Steel Chemical & Material Co., Ltd.; and "OPE-2St" (resin of formula (c-3) below), "OPE-2St 1200", and "OPE-2St 2200" (vinylbenzyl-modified polyphenylene ether) manufactured by Mitsubishi Gas Chemical Company, Inc.

[0076] [ka]

[0077] (In formula (c-3), c2 and c3 each independently represent an integer of 1 or more.)

[0078] The amount of the styryl resin is preferably 1% by mass or more, more preferably 3% by mass or more, and even more preferably 5% by mass or more, relative to 100% by mass of the nonvolatile components in the resin composition, and is preferably 25% by mass or less, more preferably 20% by mass or less, and even more preferably 18% by mass or less. When the amount of the styryl resin is within the above range, the dielectric loss tangent, the average coefficient of linear thermal expansion, and the adhesion after HAST can be particularly improved, and more usually, the adhesion before HAST and the minimum melt viscosity of the resin composition can be effectively improved.

[0079] The amount of the styryl resin is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more, relative to 100% by mass of the resin components in the resin composition, and is preferably 80% by mass or less, more preferably 75% by mass or less, and even more preferably 70% by mass or less. When the amount of the styryl resin is within the above range, the dielectric loss tangent, the average coefficient of linear thermal expansion, and the adhesion after HAST can be particularly improved, and more usually, the adhesion before HAST and the minimum melt viscosity of the resin composition can be effectively improved.

[0080] The (meth)acrylic resin refers to a resin having one or more, preferably two or more, (meth)acryloyl groups in one molecule. The term "(meth)acryloyl group" can include an acryloyl group, a methacryloyl group, and a combination thereof. Examples of the (meth)acrylic resin include cyclohexane-1,4-dimethanol di(meth)acrylate, cyclohexane-1,3-dimethanol di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,8-octanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, and the like. Low molecular weight (molecular weight less than 1000) aliphatic (meth)acrylic acid ester resins such as 1,10-decanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, trimethylolethane tri(meth)acrylate, glycerin tri(meth)acrylate, and pentaerythritol tetra(meth)acrylate; dioxane glycol di(meth)acrylate, 3,6-dioxa-1,8-octanediol di(meth)acrylate, Examples of the acrylate include low molecular weight (molecular weight less than 1000) ether-containing (meth)acrylic acid ester resins such as acrylate, 3,6,9-trioxaundecane-1,11-diol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, 9,9-bis[4-(2-acryloyloxyethoxy)phenyl]fluorene, ethoxylated bisphenol A di(meth)acrylate, and propoxylated bisphenol A di(meth)acrylate; low molecular weight (molecular weight less than 1000) isocyanurate-containing (meth)acrylic acid ester resins such as tris(3-hydroxypropyl)isocyanurate tri(meth)acrylate, tris(2-hydroxyethyl)isocyanurate tri(meth)acrylate, and ethoxylated isocyanuric acid tri(meth)acrylate; and high molecular weight (molecular weight 1000 or more) acrylic acid ester resins such as (meth)acrylic-modified polyphenylene ether resins. The term "(meth)acrylate" may include acrylates, methacrylates, and combinations thereof.Examples of commercially available (meth)acrylic resins include "A-DOG" (dioxane glycol diacrylate) manufactured by Shin-Nakamura Chemical Co., Ltd., "DCP-A" (tricyclodecane dimethanol diacrylate) and "DCP" (tricyclodecane dimethanol dimethacrylate) manufactured by Kyoeisha Chemical Co., Ltd., "KAYARAD R-684" (tricyclodecane dimethanol diacrylate) and "KAYARAD R-604" (dioxane glycol diacrylate) manufactured by Nippon Kayaku Co., Ltd., and "SA9000" and "SA9000-111" (methacrylic-modified polyphenylene ether) manufactured by SABIC.

[0081] The allyl resin refers to a resin having one or more, preferably two or more, allyl groups in one molecule. Examples of allyl resins include aromatic carboxylic acid allyl ester resins such as diallyl diphenate, triallyl trimellitate, diallyl phthalate, diallyl isophthalate, diallyl terephthalate, diallyl 2,6-naphthalenedicarboxylate, and diallyl 2,3-naphthalenecarboxylate; isocyanuric acid allyl ester resins such as 1,3,5-triallyl isocyanurate and 1,3-diallyl-5-glycidyl isocyanurate; epoxy-containing aromatic allyl resins such as 2,2-bis[3-allyl-4-(glycidyloxy)phenyl]propane; benzoxazine-containing aromatic allyl resins such as bis[3-allyl-4-(3,4-dihydro-2H-1,3-benzoxazin-3-yl)phenyl]methane; ether-containing aromatic allyl resins such as 1,3,5-triallyl ether benzene; allyl silane resins such as diallyl diphenyl silane; and resins containing multiple benzene rings and multiple allyl groups. Commercially available allyl resins include, for example, "TAIC" (1,3,5-triallyl isocyanurate) manufactured by Nippon Kasei Chemical Industry Co., Ltd., "DAD" (diallyl diphenate) manufactured by Nisshoku Techno Fine Chemical Co., Ltd., "TRIAM-705" (triallyl trimellitate) manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., "DAND" (2,3-naphthalenecarboxylic acid diallyl) manufactured by Nisshoku Techno Fine Chemical Co., Ltd., and "ALP-d" (bis[3-allyl isocyanurate) manufactured by Shikoku Chemical Industry Co., Ltd. Examples include "RE-810NM" (2,2-bis[3-allyl-4-(glycidyloxy)phenyl]propane) manufactured by Nippon Kayaku Co., Ltd., "DA-MGIC" (1,3-diallyl-5-glycidyl isocyanurate) manufactured by Shikoku Chemicals Corporation, and "NE-V-1100-70T" (a resin containing multiple benzene rings and multiple allyl groups) manufactured by DIC Corporation.

[0082] The (C) radical reactive resin may be used alone or in combination of two or more.

[0083] The radical reactive unsaturated group equivalent of the (C) radical reactive resin is preferably 20 g / eq. to 3000 g / eq., more preferably 50 g / eq. to 2500 g / eq., even more preferably 70 g / eq. to 2000 g / eq., and particularly preferably 90 g / eq. to 1500 g / eq. The radical reactive unsaturated group equivalent represents the mass of the radical reactive resin per equivalent of the radical reactive unsaturated group.

[0084] The weight average molecular weight (Mw) of the (C) radical reactive resin is preferably 40,000 or less, more preferably 10,000 or less, even more preferably 5,000 or less, and particularly preferably 3,000 or less. There is no particular limitation on the lower limit, but it can be, for example, 150 or more. The weight average molecular weight of the (C) radical reactive resin can be measured as a polystyrene-equivalent value by gel permeation chromatography (GPC).

[0085] The amount of (C) radical-reactive resin is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more, relative to 100% by mass of nonvolatile components in the resin composition, and is preferably 25% by mass or less, more preferably 24% by mass or less, and even more preferably 23% by mass or less. When the amount of (C) radical-reactive resin is within the above range, the dielectric loss tangent, average coefficient of linear thermal expansion, and adhesion after HAST can be particularly improved, and more usually, the adhesion before HAST and the minimum melt viscosity of the resin composition can be effectively improved.

[0086] The amount of (C) radical-reactive resin is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more, relative to 100% by mass of the resin components in the resin composition, and is preferably 95% by mass or less, more preferably 90% by mass or less, and even more preferably 85% by mass or less. When the amount of (C) radical-reactive resin is within the above range, the dielectric loss tangent, average coefficient of linear thermal expansion, and adhesion after HAST can be particularly improved, and more usually, the adhesion before HAST and the minimum melt viscosity of the resin composition can be effectively improved.

[0087] <(D) Inorganic filler> The resin composition according to this embodiment includes an inorganic filler (D) as component (D). The inorganic filler (D) is contained in the resin composition in the form of particles, and is contained in the cured product while maintaining the particulate form.

[0088] (D) Inorganic fillers can be inorganic compounds. Examples of (D) inorganic filler materials include silica, alumina, glass, cordierite, silicon oxide, barium sulfate, barium carbonate, talc, clay, mica powder, zinc oxide, hydrotalcite, boehmite, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, magnesium oxide, boron nitride, aluminum nitride, manganese nitride, aluminum borate, strontium carbonate, strontium titanate, calcium titanate, magnesium titanate, bismuth titanate, titanium oxide, zirconium oxide, barium titanate, barium titanate zirconate, barium zirconate, calcium zirconate, zirconium phosphate, and zirconium tungstate phosphate. Among these, silica and alumina are preferred, and silica is particularly preferred. Examples of silica include amorphous silica, fused silica, crystalline silica, synthetic silica, and hollow silica. Spherical silica is preferred. The (D) inorganic filler may be used alone or in combination of two or more.

[0089] (D) Examples of commercially available inorganic fillers include "SP60-05" and "SP507-05" manufactured by Nippon Steel Chemical & Material Co., Ltd.; "YC100C," "YA050C," "YA050C-MJE," "YA010C," "SC2500SQ," "SO-C4," "SO-C2," and "SO-C1" manufactured by Admatechs Co., Ltd.; "UFP-30," "DAW-03," and "FB-105FD" manufactured by Denka Company, Limited; "Silfil NSS-3N," "Silfil NSS-4N," and "Silfil NSS-5N" manufactured by Tokuyama Corporation; "CellSpheres" and "MGH-005" manufactured by Taiheiyo Cement Corporation; and "Sferique" and "BA-1" manufactured by JGC Catalysts and Chemicals Co., Ltd.

[0090] The (D) inorganic filler is preferably surface-treated with a surface treatment agent. In this case, it is preferable to use a (A) radical-reactive silane coupling agent as the surface treatment agent. Therefore, the (D) inorganic filler preferably includes (D-1) an inorganic filler surface-treated with a (A) radical-reactive silane coupling agent. Hereinafter, the "(D-1) inorganic filler surface-treated with a (A) radical-reactive silane coupling agent" may be referred to as the "(D-1) specially treated inorganic filler." Typically, the (D-1) specially treated inorganic filler includes particles of the above-mentioned inorganic compound and the (A) radical-reactive silane coupling agent adsorbed on the surface of the particles.

[0091] The surface treatment amount of the (D-1) specially treated inorganic filler with the (A) radical-reactive silane coupling agent is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, even more preferably 0.3% by mass or more, and preferably 3.0% by mass or less, more preferably 2.0% by mass or less, and even more preferably 1.5% by mass or less. The surface treatment amount is expressed as the ratio of the (A) radical-reactive silane coupling agent used in the surface treatment of the particles to 100% by mass of the inorganic compound particles before surface treatment. Therefore, this surface treatment amount usually represents the ratio of the (A) radical-reactive silane coupling agent adsorbed to the particles to 100% by mass of the inorganic compound particles contained in the (D-1) specially treated inorganic filler. When the surface treatment amount with the (A) radical-reactive silane coupling agent is within the above range, the dielectric loss tangent, mean coefficient of linear thermal expansion, and adhesion after HAST can be particularly improved, and more usually, the adhesion before HAST and the minimum melt viscosity of the resin composition can be effectively improved.

[0092] The (D-1) specially treated inorganic filler may be surface-treated with an arbitrary surface treatment agent other than the (A) radical-reactive silane coupling agent in combination with the (A) radical-reactive silane coupling agent. In this case, the (D-1) specially treated inorganic filler may be surface-treated in the order of the (A) radical-reactive silane coupling agent and the arbitrary surface treatment agent. Alternatively, the (D-1) specially treated inorganic filler may be surface-treated in the order of the arbitrary surface treatment agent and the (A) radical-reactive silane coupling agent. Furthermore, the (D-1) specially treated inorganic filler may be surface-treated simultaneously with the (A) radical-reactive silane coupling agent and the arbitrary surface treatment agent.

[0093] Examples of the optional surface treatment agent include a fluorine-containing silane coupling agent, an aminosilane coupling agent, an epoxysilane coupling agent, a mercaptosilane coupling agent, a silane coupling agent, an alkoxysilane, an organosilazane compound, and a titanate coupling agent. Commercially available surface treatment agents include, for example, Shin-Etsu Chemical Co., Ltd.'s "KBM403" (3-glycidoxypropyltrimethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "KBM803" (3-mercaptopropyltrimethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "KBE903" (3-aminopropyltriethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "KBM573" (N-phenyl-3-aminopropyltrimethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "SZ-31" (hexamethyldisilazane), Shin-Etsu Chemical Co., Ltd.'s "KBM103" (phenyltrimethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "KBM-4803" (long-chain epoxy-type silane coupling agent), and Shin-Etsu Chemical Co., Ltd.'s "KBM-7103" (3,3,3-trifluoropropyltrimethoxysilane). Any surface treatment agent may be used alone or in any combination of two or more.

[0094] The surface treatment amount of the (D-1) specially treated inorganic filler with any surface treatment agent may be 0% by mass or more than 0% by mass, preferably 0.1% by mass or more, more preferably 0.2% by mass or more, even more preferably 0.3% by mass or more, and preferably 3.0% by mass or less, more preferably 2.5% by mass or less, and even more preferably 2.0% by mass or less. The surface treatment amount is expressed as the ratio of the surface treatment agent used to treat the particles to 100% by mass of the particles of the inorganic compound before surface treatment. Therefore, this surface treatment amount usually represents the ratio of the surface treatment agent adsorbed to the particles to 100% by mass of the particles of the inorganic compound contained in the (D-1) specially treated inorganic filler.

[0095] The amount of the (D-1) specially treated inorganic filler is preferably 20% by mass or more, more preferably 30% by mass or more, even more preferably 35% by mass or more, and preferably 90% by mass or less, more preferably 80% by mass or less, and even more preferably 75% by mass or less, based on 100% by mass of the nonvolatile components in the resin composition. When the amount of the (D-1) specially treated inorganic filler is within this range, the dielectric loss tangent, average coefficient of linear thermal expansion, and adhesion after HAST can be particularly improved, and usually the adhesion before HAST and the minimum melt viscosity of the resin composition can be effectively improved. Unless otherwise specified, the amount of the (D-1) specially treated inorganic filler includes the amount of surface treatment agent, such as the (A) radical-reactive silane coupling agent and any surface treatment agent, adsorbed to the particles of the (D-1) specially treated inorganic filler by surface treatment.

[0096] The amount of the (D-1) specially treated inorganic filler is preferably 30% by mass or more, more preferably 40% by mass or more, and even more preferably 50% by mass or more, based on 100% by mass of the total amount of the (D) inorganic filler. When the amount of the (D-1) specially treated inorganic filler is within this range, the dielectric loss tangent, average coefficient of linear thermal expansion, and adhesion after HAST can be particularly improved, and more usually, the adhesion before HAST and the minimum melt viscosity of the resin composition can be effectively improved. As described above, the amount of the (D) inorganic filler includes the amount of the (A) radical-reactive silane coupling agent and any surface treatment agent adsorbed to the particles of the (D) inorganic filler by surface treatment.

[0097] The (D) inorganic filler may include (D-2) an inorganic filler that has not been surface-treated with (A) a radical-reactive silane coupling agent. Hereinafter, the "(D-2) (A) inorganic filler that has not been surface-treated with a radical-reactive silane coupling agent" may be referred to as the "(D-2) optional inorganic filler." The (D-2) optional inorganic filler may be an inorganic filler that has not been surface-treated with a surface treatment agent, or may be an inorganic filler that has been surface-treated with an optional surface treatment agent other than the (A) radical-reactive silane coupling agent.

[0098] The surface treatment amount of the optional inorganic filler (D-2) with the optional surface treatment agent may be 0% by mass or more than 0% by mass, preferably 0.1% by mass or more, more preferably 0.2% by mass or more, even more preferably 0.3% by mass or more, and preferably 5.0% by mass or less, more preferably 3.0% by mass or less, and even more preferably 2.0% by mass or less. The surface treatment amount is expressed as the ratio of the optional surface treatment agent used to surface treat the particles to 100% by mass of the particles of the inorganic compound before surface treatment. Therefore, this surface treatment amount usually represents the ratio of the optional surface treatment agent adsorbed to the particles to 100% by mass of the particles of the inorganic compound contained in the optional inorganic filler (D-2).

[0099] The amount of the optional inorganic filler (D-2) may be 0% by mass or more, and is preferably 1% by mass or more, more preferably 5% by mass or more, even more preferably 10% by mass or more, and is preferably 90% by mass or less, more preferably 80% by mass or less, even more preferably 75% by mass or less, relative to 100% by mass of the nonvolatile components in the resin composition. Unless otherwise specified, the amount of the optional inorganic filler (D-2) includes the amount of any surface treatment agent adsorbed to the particles of the optional inorganic filler (D-2) by surface treatment.

[0100] The average particle size of the (D) inorganic filler is preferably 0.01 μm or more, more preferably 0.05 μm or more, even more preferably 0.1 μm or more, and is preferably 10 μm or less, more preferably 5 μm or less, even more preferably 3 μm or less.

[0101] The average particle size of the (D) inorganic filler can be measured by a laser diffraction / scattering method based on Mie scattering theory. Specifically, a particle size distribution of the (D) inorganic filler is prepared on a volume basis using a laser diffraction / scattering particle size distribution analyzer, and the median diameter is used as the average particle size. A measurement sample can be prepared by weighing 100 mg of inorganic filler and 10 g of methyl ethyl ketone into a vial and dispersing the mixture ultrasonically for 10 minutes. The measurement sample is measured using a laser diffraction particle size distribution analyzer with blue and red light source wavelengths using a flow cell system to measure the volumetric particle size distribution of the (D) inorganic filler, and the average particle size can be calculated as the median diameter from the obtained particle size distribution. Examples of laser diffraction particle size distribution analyzers include the LA-960 manufactured by Horiba, Ltd.

[0102] (D) The specific surface area of ​​the inorganic filler is preferably 0.1 m 2 / g or more, more preferably 0.5m 2 / g or more, more preferably 1m 2 / g or more, particularly preferably 3m 2 / g or more, preferably 100m 2 / g or less, more preferably 70m 2 / g or less, more preferably 50m 2 / g or less, particularly preferably 40m 2 / g or less. (D) The specific surface area of ​​the inorganic filler can be measured in accordance with the BET method by adsorbing nitrogen gas onto the surface of a sample using a specific surface area measuring device (Macsorb HM-1210 manufactured by Mountech Co., Ltd.) and calculating the specific surface area using the BET multipoint method.

[0103] The amount of the (D) inorganic filler is generally 70.0% by mass or more, preferably 70.1% by mass or more, more preferably 70.2% by mass or more, and is preferably 90% by mass or less, more preferably 80% by mass or less, and even more preferably 75% by mass or less, based on 100% by mass of the nonvolatile components in the resin composition. When the amount of the (D) inorganic filler is within the above range, the dielectric loss tangent, the average coefficient of linear thermal expansion, and the adhesion after HAST can be particularly improved, and more usually, the adhesion before HAST and the minimum melt viscosity of the resin composition can be effectively improved.

[0104] The amount of inorganic compound particles contained in the (D) inorganic filler (usually the amount of the (D) inorganic filler excluding the surface treatment agent) relative to 100% by mass of the nonvolatile components in the resin composition may be the same as the aforementioned range of the amount of the (D) inorganic filler relative to 100% by mass of the nonvolatile components in the resin composition. When the amount of inorganic compound particles contained in the (D) inorganic filler is within the aforementioned range, the dielectric loss tangent, average coefficient of linear thermal expansion, and adhesion after HAST can be particularly improved, and more usually, the adhesion before HAST and the minimum melt viscosity of the resin composition can be effectively improved.

[0105] The total amount of the (A) radical-reactive silane coupling agent and the (D) inorganic filler is preferably at least 70.0 mass%, more preferably at least 70.1 mass%, and even more preferably at least 70.2 mass%, based on 100 mass% of the nonvolatile components in the resin composition. It is preferably at most 90 mass%, more preferably at most 80 mass%, and even more preferably at most 75 mass%. The total amount of the (A) radical-reactive silane coupling agent and the (D) inorganic filler typically represents the sum of the amount of the (D) inorganic filler (including the (A) radical-reactive silane coupling agent contained in the (D) inorganic filler as a surface treatment agent) and the amount of the (A) radical-reactive silane coupling agent that is not adsorbed to the (D) inorganic filler and remains free in the resin component. When the total amount of the (A) radical-reactive silane coupling agent and the (D) inorganic filler falls within the above range, the dielectric loss tangent, mean coefficient of linear thermal expansion, and adhesion after HAST can be particularly improved. Furthermore, the adhesion before HAST and the minimum melt viscosity of the resin composition can usually be effectively improved.

[0106] The total amount of the (A) radical-reactive silane coupling agent, (B) specific polystyrene material, (C) radical-reactive resin, and (D) inorganic filler is preferably 85% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more, based on 100% by mass of the nonvolatile components in the resin composition. The upper limit is usually 100% by mass or less, and may be 99% by mass or less. The total amount of the (A) radical-reactive silane coupling agent, (B) specific polystyrene material, (C) radical-reactive resin, and (D) inorganic filler usually represents the sum of the amount of the (D) inorganic filler (including the (A) radical-reactive silane coupling agent contained in the (D) inorganic filler as a surface treatment agent), the amount of the (A) radical-reactive silane coupling agent that is free in the resin component and not adsorbed to the (D) inorganic filler, the amount of the (B) specific polystyrene material, and the amount of the (C) radical-reactive resin. When the total amount of the (A) radical-reactive silane coupling agent, (B) specific polystyrene material, (C) radical-reactive resin, and (D) inorganic filler is within the above range, the dielectric loss tangent, the average coefficient of linear thermal expansion, and the adhesion after HAST can be particularly improved, and moreover, usually the adhesion before HAST and the minimum melt viscosity of the resin composition can be effectively improved.

[0107] <(E) Polymer resin> The resin composition according to this embodiment may contain a polymer resin (E) as an optional component. The polymer resin (E) as component (E) does not include components (A) to (D) described above, unless otherwise specified. The polymer resin (E) is usually contained in the resin composition in a state where it is compatible with resin components other than the polymer resin (E).

[0108] The weight-average molecular weight of the (E) polymer resin is usually greater than 5,000, preferably at least 8,000, more preferably at least 10,000, even more preferably at least 20,000, and is preferably at most 100,000, more preferably at most 70,000, even more preferably at most 60,000. The weight-average molecular weight of the (E) polymer resin can be measured as a polystyrene-equivalent value by GPC.

[0109] Examples of (E) polymer resins include phenoxy resins, polybutadiene resins, polyimide resins, polyvinyl acetal resins, polyolefin resins, polyamideimide resins, polyetherimide resins, polysulfone resins, polyethersulfone resins, polyphenylene ether resins, polycarbonate resins, polyetheretherketone resins, and polyester resins. Among these, phenoxy resins, polybutadiene resins, and polyimide resins are preferred. One type of polymer resin may be used alone, or two or more types may be used in combination.

[0110] Examples of phenoxy resins include phenoxy resins having one or more skeletons selected from the group consisting of bisphenol A, bisphenol F, bisphenol S, bisphenolacetophenone, novolac, biphenyl, fluorene, dicyclopentadiene, norbornene, naphthalene, anthracene, adamantane, terpene, and trimethylcyclohexane. The terminal of the phenoxy resin may be any functional group such as a phenolic hydroxyl group or an epoxy group. Specific examples of phenoxy resins include "1256" and "4250" manufactured by Mitsubishi Chemical Corporation (both of which are phenoxy resins containing a bisphenol A skeleton); "YX8100" manufactured by Mitsubishi Chemical Corporation (phenoxy resin containing a bisphenol S skeleton); "YX6954" manufactured by Mitsubishi Chemical Corporation (phenoxy resin containing a bisphenol acetophenone skeleton); "FX280" and "FX293" manufactured by Nippon Steel Chemical & Material Co., Ltd.; and "YX7200B35," "YL7500BH30," "YX6954BH30," "YX7553BH30," "YL7769BH30," "YL6794," "YL7213," "YL7290," and "YL7482" manufactured by Mitsubishi Chemical Corporation.

[0111] Examples of polybutadiene resins include hydrogenated polybutadiene skeleton-containing resins, hydroxy group-containing polybutadiene resins, phenolic hydroxy group-containing polybutadiene resins, carboxy group-containing polybutadiene resins, acid anhydride group-containing polybutadiene resins, epoxy group-containing polybutadiene resins, isocyanate group-containing polybutadiene resins, urethane group-containing polybutadiene resins, polyphenylene ether-polybutadiene resins, etc. Polybutadiene resins whose molecular ends are blocked with phenol resins may also be used. Specific examples of polybutadiene resins include "Ricon 130MA8," "Ricon 130MA13," "Ricon 130MA20," "Ricon 131MA5," "Ricon 131MA10," "Ricon 131MA17," "Ricon 131MA20," and "Ricon 184MA6" (anhydride-containing polybutadienes) manufactured by Cray Valley Corporation; "GQ-1000" (hydroxyl- and carboxyl-introduced polybutadiene), "G-1000," "G-2000," and "G-3000" (polybutadiene having hydroxyl groups at both ends), "GI-1000," "GI-2000," and "GI-3000" (hydrogenated polybutadiene having hydroxyl groups at both ends) manufactured by Nippon Soda Co., Ltd.; and "FCA-061L" (a hydrogenated polybutadiene-based epoxy resin) manufactured by Nagase ChemteX Corporation.

[0112] Specific examples of polybutadiene resins include polyimide resins having a polybutadiene structure, a urethane structure, and an imide structure in the molecule. The polyimide resin can be produced as a linear polyimide resin (polyimides described in JP 2006-37083 A and WO 2008 / 153208 A) using hydroxyl-terminated polybutadiene, a diisocyanate compound, and a tetrabasic acid anhydride as raw materials. The content of the butadiene structure in the polyimide resin is preferably 60% to 95% by mass, more preferably 75% to 85% by mass. For details of the polyimide resin, please refer to the descriptions in JP 2006-37083 A and WO 2008 / 153208 A, the contents of which are incorporated herein by reference.

[0113] The polyimide resin may be a resin having an imide structure (preferably a cyclic imide structure), such as an imide compound of an acid anhydride and a diamine compound; an imide compound of an acid anhydride and a diisocyanate compound; etc. Among these, an imide compound of an acid anhydride and a diamine compound is preferred. The polyimide resin may also contain an indane skeleton such as a trimethylindane skeleton, for example, a structural unit formed by polymerization of a diamine compound may contain an indane skeleton.

[0114] As the acid anhydride for producing the polyimide resin, tetracarboxylic acid anhydrides are preferred. Examples of tetracarboxylic acid anhydrides include aromatic tetracarboxylic acid dianhydrides and aliphatic tetracarboxylic acid dianhydrides, with aromatic tetracarboxylic acid dianhydrides being preferred. Examples of aromatic tetracarboxylic acid dianhydrides include benzenetetracarboxylic acid dianhydride, naphthalenetetracarboxylic acid dianhydride, anthracenetetracarboxylic acid dianhydride, and diphthalic acid dianhydride, with diphthalic acid dianhydride being preferred. Examples of diphthalic acid dianhydrides include 3,3',4,4'-benzophenonetetracarboxylic acid dianhydride, 3,3',4,4'-diphenylethertetracarboxylic acid dianhydride, 3,3',4,4'-diphenylsulfonetetracarboxylic acid dianhydride, 3,3',4,4'-biphenyltetracarboxylic acid dianhydride, 2,2',3,3'-biphenyltetracarboxylic acid dianhydride, and 2,3,3',4'-biphenyltetracarboxylic acid dianhydride. carboxylic dianhydride, 2,3,3',4'-benzophenonetetracarboxylic dianhydride, 2,3,3',4'-diphenylethertetracarboxylic dianhydride, 2,3,3',4'-diphenylsulfonetetracarboxylic dianhydride, 2,2'-bis(3,4-dicarboxyphenoxyphenyl)sulfone dianhydride, 4,4'-oxydiphthalic anhydride, methylene-4,4'-diphthalic dianhydride, 1,1-ethynylidene-4 ,4'-Diphthalic dianhydride, 2,2-propylidene-4,4'-diphthalic dianhydride, 1,2-ethylene-4,4'-diphthalic dianhydride, 1,3-trimethylene-4,4'-diphthalic dianhydride, 1,4-tetramethylene-4,4'-diphthalic dianhydride, 1,5-pentamethylene-4,4'-diphthalic dianhydride, 1,3-bis(3,4-dicarboxyphenyl)benzene dianhydride, 1,4-bis(3,4-dicarboxyphenyl)benzene dianhydride Examples of the dianhydride include 1,3-bis(3,4-dicarboxyphenoxy)benzene dianhydride, 1,4-bis(3,4-dicarboxyphenoxy)benzene dianhydride, 2,2-bis(2,3-dicarboxyphenyl)propane dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride, and 4,4'-(4,4'-isopropylidenediphenoxy)bisphthalic dianhydride.

[0115] Examples of diamine compounds for producing polyimide resins include aliphatic diamine compounds and aromatic diamine compounds, with aromatic diamine compounds being preferred. Examples of the dianiline compound include 4,4'-diamino-2,2'-ditrifluoromethyl-1,1'-biphenyl, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfide, 4-aminophenyl 4-aminobenzoate, 1,3-bis(3-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene, 2,2-bis(4-aminophenyl)propane, 4,4'-(hexafluoroisopropylidene)dianiline, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, [4-(4-aminophenoxy)phenyl]hexafluoropropane, α,α-bis[4-(4-aminophenoxy)phenyl]-1,3-diisopropylbenzene, α,α-bis[4-(4-aminophenoxy)phenyl]-1,4-diisopropylbenzene, 4,4'-(9-fluorenylidene)dianiline, 2,2-bis(3-methyl-4-aminophenyl)propane, 2,2-bis(3-methyl-4-aminophenyl)benzene, 4,4'-diamino-3,3'-dimethyl-1,1'-biphenyl, 4,4'-diamino-2,2'-dimethyl-1,1'-biphenyl, 9,9'-bis(3-methyl-4-aminophenyl)fluorene, 5-(4-aminophenoxy)-3-[4-(4-aminophenoxy)phenyl]-1,1,3-trimethylindane, and the like.

[0116] Commercially available examples of polyimide resins include "Rikacoat SN20" and "Rikacoat PN20" manufactured by New Japan Chemical Co., Ltd. Other examples of polyimide resins include linear polyimides obtained by reacting bifunctional hydroxyl-terminated polybutadiene, a diisocyanate compound, and a tetrabasic acid anhydride (as described in JP-A No. 2006-37083), and modified polyimides such as polysiloxane skeleton-containing polyimides (as described in JP-A Nos. 2002-12667 and 2000-319386).

[0117] The (E) polymer resin may contain an elastomer. The elastomer is a flexible resin, preferably a resin with rubber elasticity or a resin that exhibits rubber elasticity by polymerizing with another component. Examples of rubber elasticity include resins that exhibit a modulus of elasticity of 1 GPa or less when subjected to a tensile test in accordance with Japanese Industrial Standards (JIS K7161) at a temperature of 25°C and a humidity of 40% RH. The range of the modulus of elasticity of the elastomer is, in detail, usually 1 GPa or less, preferably 0.9 GPa or less, more preferably 0.8 GPa or less, and even more preferably 0.7 GPa or less, and preferably 0.01 GPa or more, more preferably 0.03 GPa or more, even more preferably 0.05 GPa or more, and particularly preferably 0.1 GPa or more.

[0118] The elastomer is preferably one or more types selected from resins having a glass transition temperature (Tg) of 25°C or less and resins that are liquid at 25°C or less. The glass transition temperature of resins having a glass transition temperature (Tg) of 25°C or less is preferably 20°C or less, more preferably 15°C or less. The lower limit of the glass transition temperature is not particularly limited, but is usually -15°C or higher. Furthermore, resins that are liquid at 25°C are preferably resins that are liquid at 20°C or less, more preferably resins that are liquid at 15°C or less. The glass transition temperature can be measured by DSC (differential scanning calorimetry).

[0119] The amount of the (E) polymer resin is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, and even more preferably 0.5% by mass or more, relative to 100% by mass of the nonvolatile components in the resin composition, and is preferably 20% by mass or less, more preferably 10% by mass or less, and even more preferably 5% by mass or less. When the amount of the (E) polymer resin is within the above range, the dielectric loss tangent, the average coefficient of linear thermal expansion, and the adhesion after HAST can be particularly improved, and more usually, the adhesion before HAST and the minimum melt viscosity of the resin composition can be effectively improved.

[0120] The amount of the (E) polymer resin is preferably 1% by mass or more, more preferably 2% by mass or more, and even more preferably 2.5% by mass or more, relative to 100% by mass of the resin components in the resin composition, and is preferably 15% by mass or less, more preferably 13% by mass or less, and even more preferably 11% by mass or less. When the amount of the (E) polymer resin is within the above range, the dielectric loss tangent, the average coefficient of linear thermal expansion, and the adhesion after HAST can be particularly improved, and more usually, the adhesion before HAST and the minimum melt viscosity of the resin composition can be effectively improved.

[0121] <(F) Thermosetting resin> The resin composition according to this embodiment may contain a thermosetting resin (F) as an optional component. Unless otherwise specified, the thermosetting resin (F) as component (F) does not include components (A) to (E) described above. The thermosetting resin (F) can form bonds by inducing a reaction other than a radical reaction when exposed to heat. Therefore, the resin composition can be thermally cured to form a cured product not only by the reaction of the radical-reactive resin (C) but also by the reaction of the thermosetting resin (F).

[0122] The (F) thermosetting resin is a resin that reacts with heat to form bonds and cure the resin composition, and represents a component other than components (A) to (E). Examples of this thermosetting resin include epoxy resins, phenolic resins, benzoxazine resins, active ester resins, cyanate ester resins, carbodiimide resins, acid anhydride resins, and amine resins. Among these, epoxy resins, phenolic resins, and benzoxazine resins are preferred, with benzoxazine resins being more preferred. One type of (F) thermosetting resin may be used alone, or two or more types may be used in combination.

[0123] As the epoxy resin, a curable resin having an epoxy group can be used. Examples of epoxy resins include bixylenol-type epoxy resins, bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, bisphenol S-type epoxy resins, bisphenol AF-type epoxy resins, dicyclopentadiene-type epoxy resins, trisphenol-type epoxy resins, naphthol novolac-type epoxy resins, phenol novolac-type epoxy resins, tert-butyl-catechol-type epoxy resins, naphthalene-type epoxy resins, naphthol-type epoxy resins, anthracene-type epoxy resins, glycidylamine-type epoxy resins, glycidyl ester-type epoxy resins, cresol novolac-type epoxy resins, phenol aralkyl-type epoxy resins, biphenyl-type epoxy resins, linear aliphatic epoxy resins, epoxy resins having a butadiene structure, alicyclic epoxy resins, heterocyclic epoxy resins, spiro ring-containing epoxy resins, cyclohexane-type epoxy resins, cyclohexane dimethanol-type epoxy resins, naphthylene ether-type epoxy resins, trimethylol-type epoxy resins, tetraphenylethane-type epoxy resins, isocyanurate-type epoxy resins, and phenolphthalimidine-type epoxy resins.

[0124] As described above, the resin composition may or may not contain an epoxy resin. In this case, the amount of the epoxy resin is preferably within a specific range. Specifically, the amount of the epoxy resin is preferably 3% by mass or less, more preferably 2% by mass or less, and even more preferably 1% by mass or less, relative to 100% by mass of the nonvolatile components in the resin composition. The lower limit is 0% by mass or more, and may even be 0% by mass. When the amount of the epoxy resin is within the above range, the dielectric loss tangent, the average coefficient of linear thermal expansion, and the adhesion after HAST can be particularly good, and more typically, the adhesion before HAST and the minimum melt viscosity of the resin composition can be effectively improved.

[0125] As the phenolic resin, a resin having one or more, preferably two or more, hydroxyl groups (phenolic hydroxyl groups) bonded to an aromatic ring such as a benzene ring or a naphthalene ring per molecule can be used. From the viewpoint of heat resistance and water resistance, a phenolic resin having a novolac structure is preferred. From the viewpoint of adhesion, a nitrogen-containing phenolic resin is preferred, and a triazine skeleton-containing phenolic resin is more preferred. Among them, a triazine skeleton-containing phenolic novolac resin is preferred from the viewpoint of highly satisfying heat resistance, water resistance, and adhesion. Specific examples of phenolic resins include "MEH-7700", "MEH-7810", "MEH-7851", and "MEH-8000H" manufactured by Meiwa Chemical Industry Co., Ltd.; "NHN", "CBN", and "GPH" manufactured by Nippon Kayaku Co., Ltd.; and "SN-170", "SN-180", "SN-190", "SN-475", "SN-485", "SN-495", "SN-495V", and "SN- 375" and "SN-395" manufactured by DIC Corporation; "TD-2090", "TD-2090-60M", "LA-7052", "LA-7054", "LA-1356", "LA-3018", "LA-3018-50P", "LA-1356", "TD2090", and "TD-2090-60M" manufactured by DIC Corporation; and "GDP-6115L", "GDP-6115H", and "ELPC75" manufactured by Gun-ei Chemical Co., Ltd.

[0126] The benzoxazine resin may be a resin having one or more, preferably two or more, benzoxazine rings in one molecule. Specific examples of the benzoxazine resin include "JBZ-OP100D" and "ODA-BOZ" manufactured by JFE Chemical Corporation; "HFB2006M" manufactured by Showa Polymer Co., Ltd.; and "Pd", "Fa", and "ALP-d" manufactured by Shikoku Chemicals Corporation. The benzoxazine resin may be used alone or in combination of two or more.

[0127] The amount of the benzoxazine resin is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, even more preferably 1% by mass or more, and preferably 15% by mass or less, more preferably 10% by mass or less, and even more preferably 5% by mass or less, relative to 100% by mass of the nonvolatile components in the resin composition. When the amount of the benzoxazine resin is within the above range, the dielectric loss tangent, the average coefficient of linear thermal expansion, and the adhesion after HAST can be particularly improved, and more usually, the adhesion before HAST and the minimum melt viscosity of the resin composition can be effectively improved.

[0128] In one example, the active group equivalent of the (F) thermosetting resin is preferably 50 g / eq or more, more preferably 60 g / eq or more, even more preferably 80 g / eq or more, even more preferably 100 g / eq or more, and even more preferably 110 g / eq or more, and is preferably 5,000 g / eq or less, more preferably 3,000 g / eq or less, even more preferably 2,000 g / eq or less, even more preferably 1,000 g / eq or less, even more preferably 500 g / eq or less, and even more preferably 300 g / eq or less. The active group equivalent represents the mass of resin per equivalent of active group.

[0129] For example, the weight average molecular weight (Mw) of the thermosetting resin (F) is preferably in the range of 100 to 5,000, more preferably 250 to 3,000, and even more preferably 400 to 1,500. The weight average molecular weight can be measured by gel permeation chromatography (GPC) as a polystyrene-equivalent value.

[0130] The amount of the (F) thermosetting resin is preferably 0.1% by mass or more, more preferably 0.3% by mass or more, and even more preferably 0.5% by mass or more, relative to 100% by mass of the nonvolatile components in the resin composition, and is preferably 10% by mass or less, more preferably 8% by mass or less, and even more preferably 6% by mass or less. When the amount of the (F) thermosetting resin is within the above range, the dielectric loss tangent, the average coefficient of linear thermal expansion, and the adhesion after HAST can be particularly improved, and more usually, the adhesion before HAST and the minimum melt viscosity of the resin composition can be effectively improved.

[0131] The amount of the (F) thermosetting resin is preferably 0.1% by mass or more, more preferably 1% by mass or more, and even more preferably 2% by mass or more, relative to 100% by mass of the resin components in the resin composition, and is preferably 20% by mass or less, more preferably 15% by mass or less, and particularly preferably 10% by mass or less. When the amount of the (F) thermosetting resin is within the above range, the dielectric loss tangent, the average coefficient of linear thermal expansion, and the adhesion after HAST can be particularly improved, and more usually, the adhesion before HAST and the minimum melt viscosity of the resin composition can be effectively improved.

[0132] <(G) Polymerization initiator> The resin composition according to the present embodiment may contain a polymerization initiator (G) as an optional component. The polymerization initiator (G) as component (G) does not include those corresponding to the above-mentioned components (A) to (F), unless otherwise specified. The polymerization initiator (G) as component (G) can promote the reaction between the radical-reactive silane coupling agent (A) and the radical-reactive resin (C), thereby promoting the curing of the resin composition.

[0133] As the (G) polymerization initiator, a compound capable of generating free radicals upon heating is usually used. Examples of the (G) polymerization initiator include peroxide radical polymerization initiators and azo radical polymerization initiators, among which peroxide radical polymerization initiators are preferred.

[0134] Examples of the peroxide radical polymerization initiator include hydroperoxide compounds such as 1,1,3,3-tetramethylbutyl hydroperoxide; dialkyl peroxide compounds such as tert-butylcumyl peroxide, di-tert-butyl peroxide, di-tert-hexyl peroxide, dicumyl peroxide, 1,4-bis(1-tert-butylperoxy-1-methylethyl)benzene, and 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane; and diacyl peroxide compounds such as dilauroyl peroxide, didecanoyl peroxide, dicyclohexyl peroxydicarbonate, and bis(4-tert-butylcyclohexyl)peroxydicarbonate. peroxyester compounds such as tert-butyl peroxyacetate, tert-butyl peroxybenzoate, tert-butylperoxyisopropyl monocarbonate, tert-butylperoxy-2-ethylhexanoate, tert-butylperoxyneodecanoate, tert-hexylperoxyisopropyl monocarbonate, tert-butyl peroxylaurate, (1,1-dimethylpropyl) 2-ethylperhexanoate, tert-butyl 2-ethylperhexanoate, tert-butyl 3,5,5-trimethylperhexanoate, tert-butylperoxy-2-ethylhexyl monocarbonate, and tert-butylperoxymaleic acid; and the like.

[0135] Examples of the azo radical polymerization initiator include azonitrile compounds such as 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), 1,1'-azobis(cyclohexane-1-carbonitrile), 1-[(1-cyano-1-methylethyl)azo]formamide, and 2-phenylazo-4-methoxy-2,4-dimethyl-valeronitrile; 2,2'-azobis[2-methyl-N-[1,1-bis(hydroxymethyl)-2-hydroxyethyl]propionamide], and 2,2'-azobis[2-methyl-N-[1,1-bis(hydroxymethyl)-2-hydroxyethyl]propionamide]. azoamide compounds such as 2,2'-azobis[2-methyl-N-[2-(1-hydroxybutyl)]-propionamide], 2,2'-azobis[2-methyl-N-(2-hydroxyethyl)-propionamide], 2,2'-azobis(2-methylpropionamide) dihydrate, 2,2'-azobis[N-(2-propenyl)-2-methylpropionamide], 2,2'-azobis(N-butyl-2-methylpropionamide), and 2,2'-azobis(N-cyclohexyl-2-methylpropionamide); alkyl azo compounds such as 2,2'-azobis(2,4,4-trimethylpentane) and 2,2'-azobis(2-methylpropane); and the like.

[0136] Commercially available (G) polymerization initiators include, for example, "Perbutyl C," "Perbutyl A," "Perbutyl P," "Perbutyl L," "Perbutyl O," "Perbutyl ND," "Perbutyl Z," "Perbutyl I," "Percumyl P," "Percumyl D," "Perhexyl D," "Perhexyl A," "Perhexyl I," "Perhexyl Z," "Perhexyl ND," "Perhexyl O," and "Perhexyl PV," all manufactured by NOF Corporation. One (G) polymerization initiator may be used alone, or two or more may be used in combination.

[0137] The amount of (G) polymerization initiator is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, even more preferably 0.1% by mass or more, relative to 100% by mass of the nonvolatile components in the resin composition, and is preferably 5% by mass or less, more preferably 2% by mass or less, even more preferably 1% by mass or less.

[0138] The amount of the (G) polymerization initiator is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and even more preferably 0.5% by mass or more, relative to 100% by mass of the resin component in the resin composition, and is preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 2% by mass or less.

[0139] <(H) Curing accelerator> The resin composition according to this embodiment may contain a curing accelerator (H) as an optional component. The curing accelerator (H) as component (H) does not include components (A) to (G) described above. The curing accelerator (H) acts as a catalyst for the reaction of the thermosetting resin (F) to accelerate the curing of the resin composition.

[0140] Examples of the (H) curing accelerator include phosphorus-based curing accelerators, urea-based curing accelerators, guanidine-based curing accelerators, imidazole-based curing accelerators, metal-based curing accelerators, amine-based curing accelerators, etc. One type of (H) curing accelerator may be used alone, or two or more types may be used in combination.

[0141] Examples of the phosphorus-based curing accelerator include aliphatic phosphonium salts such as tetrabutylphosphonium bromide, tetrabutylphosphonium chloride, tetrabutylphosphonium acetate, tetrabutylphosphonium decanoate, tetrabutylphosphonium laurate, bis(tetrabutylphosphonium)pyromellitate, tetrabutylphosphonium hydrogenhexahydrophthalate, tetrabutylphosphonium 2,6-bis[(2-hydroxy-5-methylphenyl)methyl]-4-methylphenolate, and di-tert-butyldimethylphosphonium tetraphenylborate; methyltriphenylphosphonium bromide, ethyltriphenylphosphonium bromide, propyltriphenylphosphonium bromide, butyltriphenylphosphonium bromide, benzyltriphenylphosphonium chloride, tetraphenylphosphonium bromide, p-tolyltriphenylphosphonium tetra-p-tolylborate, and tetraphenylphosphonium tetra-p-tolylborate. aromatic phosphonium salts such as tetraphenylborate, tetraphenylphosphonium tetra-p-tolylborate, triphenylethylphosphonium tetraphenylborate, tris(3-methylphenyl)ethylphosphonium tetraphenylborate, tris(2-methoxyphenyl)ethylphosphonium tetraphenylborate, (4-methylphenyl)triphenylphosphonium thiocyanate, tetraphenylphosphonium thiocyanate, and butyltriphenylphosphonium thiocyanate; aromatic phosphine-borane complexes such as triphenylphosphine-triphenylborane; aromatic phosphine-quinone adducts such as triphenylphosphine-p-benzoquinone adduct; aliphatic phosphines such as tributylphosphine, tri-tert-butylphosphine, trioctylphosphine, di-tert-butyl(2-butenyl)phosphine, di-tert-butyl(3-methyl-2-butenyl)phosphine, and tricyclohexylphosphine;Dibutylphenylphosphine, di-tert-butylphenylphosphine, methyldiphenylphosphine, ethyldiphenylphosphine, butyldiphenylphosphine, diphenylcyclohexylphosphine, triphenylphosphine, tri-o-tolylphosphine, tri-m-tolylphosphine, tri-p-tolylphosphine, tris(4-ethylphenyl)phosphine, tris(4-propylphenyl)phosphine, tris(4-isopropylphenyl)phosphine, tris(4-butylphenyl)phosphine, tris(4-tert-butylphenyl)phosphine, tris(2,4-dimethylphenyl)phosphine, tris(2,5-dimethylphenyl)phosphine, tris(2,6-dimethylphenyl)phosphine aromatic phosphines such as benzene, tris(3,5-dimethylphenyl)phosphine, tris(2,4,6-trimethylphenyl)phosphine, tris(2,6-dimethyl-4-ethoxyphenyl)phosphine, tris(2-methoxyphenyl)phosphine, tris(4-methoxyphenyl)phosphine, tris(4-ethoxyphenyl)phosphine, tris(4-tert-butoxyphenyl)phosphine, diphenyl-2-pyridylphosphine, 1,2-bis(diphenylphosphino)ethane, 1,3-bis(diphenylphosphino)propane, 1,4-bis(diphenylphosphino)butane, 1,2-bis(diphenylphosphino)acetylene, and 2,2'-bis(diphenylphosphino)diphenyl ether;

[0142] Examples of the urea-based curing accelerator include 1,1-dimethylurea; aliphatic dimethylureas such as 1,1,3-trimethylurea, 3-ethyl-1,1-dimethylurea, 3-cyclohexyl-1,1-dimethylurea, and 3-cyclooctyl-1,1-dimethylurea; 3-phenyl-1,1-dimethylurea, 3-(4-chlorophenyl)-1,1-dimethylurea, 3-(3,4-dichlorophenyl)-1,1-dimethylurea, 3-(3-chloro-4-methylphenyl)-1,1-dimethylurea, 3-(2-methylphenyl)-1,1-dimethylurea, 3-(4-methylphenyl)-1,1-dimethylurea, and 3-(3,4-dimethylphenyl)-1,1-dimethylurea. aromatic dimethylureas such as toluene bis(dimethylurea), 3-(4-isopropylphenyl)-1,1-dimethylurea, 3-(4-methoxyphenyl)-1,1-dimethylurea, 3-(4-nitrophenyl)-1,1-dimethylurea, 3-[4-(4-methoxyphenoxy)phenyl]-1,1-dimethylurea, 3-[4-(4-chlorophenoxy)phenyl]-1,1-dimethylurea, 3-[3-(trifluoromethyl)phenyl]-1,1-dimethylurea, N,N-(1,4-phenylene)bis(N',N'-dimethylurea), and N,N-(4-methyl-1,3-phenylene)bis(N',N'-dimethylurea) [toluene bisdimethylurea].

[0143] Examples of guanidine curing accelerators include dicyandiamide, 1-methylguanidine, 1-ethylguanidine, 1-cyclohexylguanidine, 1-phenylguanidine, 1-(o-tolyl)guanidine, dimethylguanidine, diphenylguanidine, trimethylguanidine, tetramethylguanidine, pentamethylguanidine, 1,5,7-triazabicyclo[4.4.0]dec-5-ene, 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene, 1-methylbiguanide, 1-ethylbiguanide, 1-n-butylbiguanide, 1-n-octadecylbiguanide, 1,1-dimethylbiguanide, 1,1-diethylbiguanide, 1-cyclohexylbiguanide, 1-allylbiguanide, 1-phenylbiguanide, and 1-(o-tolyl)biguanide.

[0144] Examples of the imidazole curing accelerator include 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, and 1-benzyl-2-methylimidazole. Phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-phenylimidazolium trimellitate, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2,4-diamino-6-[2'-methylimidazolyl -(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-undecylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-ethyl-4'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine isocyanuric acid adduct, 2-phenylimidazole isocyanuric acid adduct Examples of imidazole compounds include 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazole, 1-dodecyl-2-methyl-3-benzylimidazolium chloride, 2-methylimidazoline, and 2-phenylimidazoline, as well as adducts of imidazole compounds with epoxy resins. Commercially available imidazole curing accelerators include "1B2PZ," "2E4MZ," "2MZA-PW," "2MZ-OK," "2MA-OK," "2MA-OK-PW," "2PHZ," "2PHZ-PW," "Cl1Z," "Cl1Z-CN," "Cl1Z-CNS," and "C11Z-A" manufactured by Shikoku Chemicals Corporation; and "P200-H50" manufactured by Mitsubishi Chemical Corporation.

[0145] Examples of metal-based curing accelerators include organometallic complexes or organometallic salts of metals such as cobalt, copper, zinc, iron, nickel, manganese, and tin. Specific examples of organometallic complexes include organic cobalt complexes such as cobalt(II) acetylacetonate and cobalt(III) acetylacetonate, organic copper complexes such as copper(II) acetylacetonate, organic zinc complexes such as zinc(II) acetylacetonate, organic iron complexes such as iron(III) acetylacetonate, organic nickel complexes such as nickel(II) acetylacetonate, and organic manganese complexes such as manganese(II) acetylacetonate. Examples of organometallic salts include zinc octoate, tin octoate, zinc naphthenate, cobalt naphthenate, tin stearate, and zinc stearate.

[0146] Examples of the amine curing accelerator include trialkylamines such as triethylamine and tributylamine, 4-dimethylaminopyridine, benzyldimethylamine, 2,4,6-tris(dimethylaminomethyl)phenol, 1,8-diazabicyclo(5,4,0)-undecene, etc. Commercially available amine curing accelerators may be used, such as "MY-25" manufactured by Ajinomoto Fine-Techno Co., Inc.

[0147] The amount of (H) curing accelerator is preferably 0.01% by mass or more, more preferably 0.02% by mass or more, even more preferably 0.05% by mass or more, and is preferably 2% by mass or less, more preferably 1% by mass or less, even more preferably 0.1% by mass or less, relative to 100% by mass of non-volatile components in the resin composition.

[0148] The amount of (H) curing accelerator is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, even more preferably 0.2% by mass or more, relative to 100% by mass of the resin component in the resin composition, and is preferably 5% by mass or less, more preferably 1% by mass or less, even more preferably 0.5% by mass or less.

[0149] <(I) Optional Additives> The resin composition according to the present embodiment may further contain (I) an optional additive as an optional component. The (I) optional additive as component (I) does not include those corresponding to the above-mentioned components (A) to (H). Examples of the (I) optional additive include organometallic compounds such as organocopper compounds, organozinc compounds, and organocobalt compounds; colorants such as phthalocyanine blue, phthalocyanine green, iodine green, diazo yellow, crystal violet, titanium oxide, and carbon black; polymerization inhibitors such as hydroquinone, catechol, pyrogallol, and phenothiazine; leveling agents such as silicone-based leveling agents and acrylic polymer-based leveling agents; thickeners such as bentone and montmorillonite; antifoaming agents such as silicone-based antifoaming agents, acrylic-based antifoaming agents, fluorine-based antifoaming agents, and vinyl resin-based antifoaming agents; ultraviolet absorbers such as benzotriazole-based ultraviolet absorbers; and adhesion promoters such as triazole-based adhesion promoters, tetrazole-based adhesion promoters, and triazine-based adhesion promoters. Examples of additives include antioxidants such as hindered phenol antioxidants, fluorescent brighteners such as stilbene derivatives, surfactants such as fluorine-based surfactants and silicone-based surfactants, flame retardants such as phosphorus-based flame retardants (e.g., phosphate ester compounds, phosphazene compounds, phosphinic acid compounds, and red phosphorus), nitrogen-based flame retardants (e.g., melamine sulfate), halogen-based flame retardants, and inorganic flame retardants (e.g., antimony trioxide), dispersants such as phosphate ester-based dispersants, polyoxyalkylene-based dispersants, acetylene-based dispersants, silicone-based dispersants, anionic dispersants, and cationic dispersants, and stabilizers such as borate-based stabilizers, titanate-based stabilizers, aluminate-based stabilizers, zirconate-based stabilizers, isocyanate-based stabilizers, carboxylic acid-based stabilizers, and carboxylic anhydride-based stabilizers. (I) Optional additives may be used alone or in combination of two or more.

[0150] <(J) Solvent> The resin composition may further contain a (J) solvent as an optional volatile component in addition to the nonvolatile components (A) to (I) described above. Typically, an organic solvent is used as the (J) solvent. Examples of the organic solvent include ketone-based solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ester-based solvents such as methyl acetate, ethyl acetate, butyl acetate, isobutyl acetate, isoamyl acetate, methyl propionate, ethyl propionate, and γ-butyrolactone; ether-based solvents such as tetrahydropyran, tetrahydrofuran, 1,4-dioxane, diethyl ether, diisopropyl ether, dibutyl ether, diphenyl ether, and anisole; alcohol-based solvents such as methanol, ethanol, propanol, butanol, and ethylene glycol; 2-ethoxyethyl acetate, propylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, ethyl diglycol acetate, γ-butyrolactone, and methyl methoxypropionate. Examples of suitable solvents include ether ester solvents such as ethyl acetate; ester alcohol solvents such as methyl lactate, ethyl lactate, and methyl 2-hydroxyisobutyrate; ether alcohol solvents such as 2-methoxypropanol, 2-methoxyethanol, 2-ethoxyethanol, propylene glycol monomethyl ether, and diethylene glycol monobutyl ether (butyl carbitol); amide solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone; sulfoxide solvents such as dimethyl sulfoxide; nitrile solvents such as acetonitrile and propionitrile; aliphatic hydrocarbon solvents such as hexane, cyclopentane, cyclohexane, and methylcyclohexane; and aromatic hydrocarbon solvents such as benzene, toluene, xylene, ethylbenzene, and trimethylbenzene. (J) Solvents may be used singly or in combination of two or more.

[0151] The amount of (J) solvent, relative to 100% by mass of all components in the resin composition, can be, for example, 60% by mass or less, 40% by mass or less, 30% by mass or less, 20% by mass or less, 15% by mass or less, or 10% by mass or less, or may be 0% by mass.

[0152] <Method of manufacturing resin composition> The resin composition can be produced, for example, by mixing components that can be contained in the resin composition. Thus, the resin composition can be produced by a production method including a step of mixing (A) a radical-reactive silane coupling agent, (B) a specific polystyrene material, (C) a radical-reactive resin, and (D) an inorganic filler. This production method may also include a step of mixing optional components such as components (E) to (J). Components (A) to (J) may be mixed in part or all at the same time, or they may be mixed sequentially.

[0153] In particular, the resin composition containing the (D-1) specially treated inorganic filler is preferably produced by a production method including the steps of: mixing (A) a radical-reactive silane coupling agent with (D') an inorganic filler before surface treatment to obtain the (D-1) specially treated inorganic filler; and mixing the (D-1) specially treated inorganic filler, (B) a specific polystyrene material, and (C) a radical-reactive resin.

[0154] (D') Pre-surface-treated inorganic filler refers to an inorganic filler before being subjected to surface treatment with (A) a radical-reactive silane coupling agent. Hereinafter, the "(D') pre-surface-treated inorganic filler" may be referred to as the "(D') pre-treatment filler." The (D') pre-treatment filler may be particles that have not been surface-treated with any surface treatment agent. Alternatively, the (D') pre-treatment filler may be particles that have been surface-treated with any surface treatment agent.

[0155] The surface treatment of the (D') pre-treatment filler can be carried out by contacting the (D') pre-treatment filler with the (A) radical-reactive silane coupling agent. For example, the (D') pre-treatment filler can be stirred while the (A) radical-reactive silane coupling agent is supplied to the (D') pre-treatment filler, thereby contacting the (D') pre-treatment filler with the (A) radical-reactive silane coupling agent, thereby carrying out the surface treatment. From the viewpoint of carrying out a uniform surface treatment, the (A) radical-reactive silane coupling agent is preferably supplied by spraying.

[0156] After the (D') pre-treatment filler is surface-treated with (A) a radical-reactive silane coupling agent to obtain (D-1) a specifically treated inorganic filler, the (D-1) specifically treated inorganic filler may be further surface-treated with an optional surface treatment agent. The surface treatment with the optional surface treatment agent may be carried out, for example, by the same method as the surface treatment with (A) a radical-reactive silane coupling agent. Furthermore, the surface treatment with (A) a radical-reactive silane coupling agent and the surface treatment with the optional surface treatment agent may be carried out simultaneously.

[0157] After obtaining the (D-1) specially treated inorganic filler, a resin composition can be obtained by mixing the (D) inorganic filler containing the (D-1) specially treated inorganic filler, the (B) specific polystyrene material, and the (C) radical-reactive resin, as well as any optional components, as needed. These components may be mixed in part or in whole simultaneously, or sequentially. Furthermore, as described above, the temperature may be appropriately set during the process of mixing the components, and thus heating and / or cooling may be performed temporarily or throughout the process. Furthermore, stirring or shaking may be performed during the process of mixing the components.

[0158] <Characteristics of the resin composition and its cured product> The resin composition according to this embodiment can usually have a low minimum melt viscosity. Therefore, for example, when a resin composition layer is formed on a substrate having wiring on its surface, the wiring on the substrate surface can be well embedded in the resin composition layer. The specific range of the minimum melt viscosity of the resin composition is preferably 5000 poise or less, more preferably 4000 poise or less, and even more preferably 3400 poise or less. The lower limit can be, for example, 500 poise or more, 1000 poise or more, etc.

[0159] The minimum melt viscosity of the resin composition can be determined by measuring the dynamic viscoelastic modulus using a dynamic viscoelasticity measuring device while raising the temperature from a starting temperature of 60°C to 200°C under measurement conditions of a heating rate of 5°C / min, a measurement interval temperature of 2.5°C, and a vibration frequency of 1 Hz, and obtaining the minimum melt viscosity as the minimum value of the measured melt viscosities. A specific measurement method can be the method described in <Test 1. Measurement test of minimum melt viscosity of resin composition> in the Examples below.

[0160] A cured product can be obtained by curing the resin composition according to this embodiment. Among the components contained in the resin composition, volatile components such as (J) solvent can usually be evaporated by heat during curing. Therefore, the cured product of the resin composition can contain non-volatile components such as components (A) to (I) or their reaction products.

[0161] The cured product of the resin composition according to this embodiment can have excellent dielectric properties, for example, a low dielectric dissipation factor (Df). In one example, the dielectric dissipation factor (Df) of the cured product is preferably 0.0100 or less, more preferably 0.0050 or less, even more preferably 0.0030 or less, and particularly preferably 0.0026 or less. The lower limit of the dielectric dissipation factor (Df) is not particularly limited, and can be, for example, 0.0010 or more. The dielectric dissipation factor (Df) of the cured product can be measured by a cavity resonance perturbation method at a measurement frequency of 5.8 GHz and a measurement temperature of 23°C. When the sample is a resin composition before curing, the resin composition may be heated at 190°C for 90 minutes to obtain a cured product, and the dielectric dissipation factor (Df) of the cured product may be measured. A specific measurement method may be as described in "Test 2. Measurement of Dielectric Dissipation Factor (Df) and Average Coefficient of Linear Thermal Expansion (CTE)" in the Examples section below.

[0162] The cured product of the resin composition according to this embodiment can exhibit a small degree of thermal expansion and thus a low mean coefficient of linear thermal expansion (CTE). In one example, the mean coefficient of linear thermal expansion (CTE) of the cured product is preferably 30 ppm / °C or less, more preferably 28 ppm / °C or less, and even more preferably 26 ppm / °C or less. The lower limit of the mean coefficient of linear thermal expansion (CTE) is not particularly limited and can be, for example, 10 ppm / °C or more. The mean coefficient of linear thermal expansion (CTE) of the cured product can be calculated by performing thermomechanical analysis twice consecutively using a tensile load method under measurement conditions of a load of 1 g and a heating rate of 5°C / min, and then calculating the value of the thermal expansion coefficient from 25°C to 150°C in the second measurement. When the sample is a resin composition before curing, the resin composition may be heated at 190°C for 90 minutes to obtain a cured product, and the mean coefficient of linear thermal expansion (CTE) of the cured product may be measured. A specific measurement method may be as described in "Test 2. Measurement of Dielectric Loss Tangent (Df) and Mean Coefficient of Linear Thermal Expansion (CTE)" in the Examples section below.

[0163] The cured product of the resin composition according to this embodiment exhibits excellent adhesion to the conductor layer after HAST. In particular, the cured product of the resin composition according to this embodiment exhibits excellent adhesion to metal foil. When forming an insulating layer for a circuit board using the cured product, the insulating layer may be formed on a conductor layer, such as wiring, formed on the surface of an inner layer board. The conductor layer generally comprises a metal foil. Therefore, high adhesion between the cured product and the metal foil can enhance adhesion between the conductor layer and the insulating layer. Furthermore, this excellent adhesion after HAST is expected to contribute to extending the life of the circuit board. For example, when an insulating layer is formed using the cured product using the method described in "Test 3: Evaluation of Adhesion with Conductive Layer" in the Examples below and the adhesion strength between the insulating layer and the conductor layer after HAST is measured, high adhesion strength can be obtained. The specific range of adhesion strength after HAST is preferably 0.30 kgf / cm or more, more preferably 0.35 kgf / cm or more, and even more preferably 0.40 kgf / cm or more. There is no particular upper limit, and it can be, for example, 1.5 kgf / cm or less.

[0164] The cured product of the resin composition according to this embodiment typically exhibits excellent adhesion to the conductor layer before HAST. For example, when an insulating layer is formed using the cured product by the method described in "Test 3: Evaluation Test for Adhesion to Conductor Layer" in the Examples below, and the adhesion strength between the insulating layer and the conductor layer is measured before HAST, high adhesion strength can be obtained. A specific range of adhesion strength before HAST is preferably 0.40 kgf / cm or more, more preferably 0.45 kgf / cm or more, and even more preferably 0.50 kgf / cm or more. There is no particular upper limit, and it can be, for example, 2 kgf / cm or less.

[0165] <Applications of resin composition> The resin composition according to this embodiment can be used to form an insulating layer, and is particularly preferably used to form an insulating layer for a circuit board. The resin composition can also be used to manufacture a resin sheet. Typically, an insulating layer is formed using this resin sheet. The resin composition may also be used for other purposes, such as a solder resist, an underfill material, a die bonding material, a hole filling resin, a sealing resin, or a component embedding resin.

[0166] <Resin sheet> A resin sheet according to one embodiment of the present invention includes a support and a resin composition layer formed on the support. The resin composition layer contains the resin composition described above, and preferably contains only the resin composition described above.

[0167] Since the resin composition layer contains the above-mentioned resin composition, the cured product obtained by curing the resin composition layer of the resin sheet has a low dielectric loss tangent and mean linear thermal expansion coefficient, and can have excellent adhesion to the conductor layer after HAST. Therefore, when the insulating layer of a circuit board is formed using this cured product, it is possible to obtain a circuit board with low transmission loss, suppressed warping, and high reliability over a long period of time. Furthermore, since the resin composition usually has a low minimum melt viscosity, when the resin sheet and the inner layer board are laminated, the wiring on the surface of the inner layer board can be well embedded by the resin composition layer.

[0168] From the viewpoint of thinning, the thickness of the resin composition layer provided in the resin sheet is preferably 200 μm or less, more preferably 150 μm or less, and even more preferably 100 μm or less. The lower limit of the thickness of the resin composition layer can be, for example, 1 μm or more, 3 μm or more, 5 μm or more, etc.

[0169] Examples of the support include plastic film, metal foil, and release paper, with plastic film and metal foil being preferred.

[0170] When a film of a plastic material is used as the support, examples of the plastic material include polyesters such as polyethylene terephthalate (hereinafter sometimes abbreviated as "PET") and polyethylene naphthalate (hereinafter sometimes abbreviated as "PEN"), polycarbonate (hereinafter sometimes abbreviated as "PC"), acrylics such as polymethyl methacrylate (PMMA), cyclic polyolefins, triacetyl cellulose (TAC), polyether sulfide (PES), polyether ketone, polyimide, etc. Among these, polyethylene terephthalate and polyethylene naphthalate are preferred, with inexpensive polyethylene terephthalate being particularly preferred.

[0171] When a metal foil is used as the support, examples of the metal foil include copper foil and aluminum foil, with copper foil being preferred. The copper foil may be a foil made of a single metal, copper, or an alloy of copper and another metal (e.g., tin, chromium, silver, magnesium, nickel, zirconium, silicon, titanium, etc.).

[0172] The surface of the support that is to be bonded to the resin composition layer may be subjected to a surface treatment such as matte treatment, corona treatment, or antistatic treatment.

[0173] The support may be a support with a release layer, which has a release layer on the surface that bonds with the resin composition layer. Examples of the release agent used in the release layer of the support with a release layer include one or more release agents selected from the group consisting of alkyd-based release agents, polyolefin-based release agents, urethane-based release agents, and silicone-based release agents. Commercially available products may be used as the support with a release layer, including PET films having a release layer primarily composed of a silicone-based release agent or an alkyd resin-based release agent, such as "PET501010," "SK-1," "AL-5," and "AL-7" manufactured by Lintec Corporation; "Lumirror T60" manufactured by Toray Industries, Inc.; "Purex" manufactured by Teijin Limited; and "Uni-Peel" manufactured by Unitika Limited.

[0174] The thickness of the support is not particularly limited, but is preferably 1 μm or more, more preferably 5 μm or more, even more preferably 10 μm or more, and is preferably 75 μm or less, more preferably 60 μm or less, even more preferably 50 μm or less. When a support with a release layer is used, it is preferable that the thickness of the entire support with a release layer is within the above range.

[0175] The resin sheet may include any optional member as needed. For example, the resin sheet may include a protective film for protecting the resin composition layer. The protective film is usually provided on the surface of the resin composition layer that is not bonded to the support (i.e., the surface opposite to the support). The thickness of the protective film is not particularly limited, but is, for example, 1 μm to 40 μm. When the protective film is provided, adhesion of dust and scratches to the surface of the resin composition layer can be suppressed.

[0176] The resin sheet can be produced, for example, by a method including forming a resin composition layer on a support. Specifically, the resin sheet can be produced by applying a liquid (varnish-like) resin composition directly or by mixing a solvent and the resin composition to prepare a liquid (varnish-like) resin composition, applying the liquid (varnish-like) resin composition to a support, and then drying it as necessary to form a resin composition layer. The solvent may be the same as the (J) solvent described as a component of the resin composition.

[0177] The resin composition can be applied using a coating device such as a die coater. Drying can be performed by a drying method such as heating or hot air blowing. The drying conditions are not particularly limited, but drying is typically performed so that the solvent content in the resin composition layer is 10% by mass or less, preferably 5% by mass or less. Although this may vary depending on the boiling point of the solvent, for example, when a resin composition containing 30% by mass to 60% by mass of solvent is used, a resin composition layer can be formed by drying at 50°C to 150°C for 3 to 10 minutes.

[0178] The produced resin sheet can be stored by being wound up in a roll. When the resin sheet has a protective film, the resin sheet can usually be used by peeling off the protective film.

[0179] <Circuit board> A circuit board according to one embodiment of the present invention includes a cured product of the resin composition described above. Typically, the circuit board includes an insulating layer, and this insulating layer includes a cured product of the resin composition. The insulating layer may include only a cured product of the resin composition. Typically, the insulating layer can have the same properties as the cured product of the resin composition described above. The thickness of the insulating layer is not particularly limited and can be, for example, in the same range as the thickness of the resin composition layer included in the resin sheet.

[0180] Preferably, the circuit board includes an inner layer substrate and the insulating layer is provided on the inner layer substrate. The circuit board may also include a conductor layer. For example, the conductor layer may be provided on an insulating layer. An example of a preferred method for manufacturing a circuit board will be described below.

[0181] A preferred example of a method for manufacturing a circuit board includes the steps of: Step (I) of forming a resin composition layer on an inner layer substrate; a step (II) of curing the resin composition layer; Includes:

[0182] An "inner layer substrate" is a member that serves as the base material of a circuit board, and examples thereof include glass epoxy substrates, metal substrates, polyester substrates, polyimide substrates, BT resin substrates, and thermosetting polyphenylene ether substrates. The inner layer substrate may have a conductor layer on one or both sides. The conductor layer of the inner layer substrate may be patterned. An inner layer substrate having a conductor layer (circuit) formed on one or both sides of the substrate is sometimes called an "inner layer circuit board." The term "inner layer substrate" also includes intermediate products on which insulating layers and / or conductor layers are to be further formed during the production of a circuit board. In addition, inner layer substrates with built-in components may also be used.

[0183] The resin composition layer may be formed on the inner layer substrate by, for example, a forming method including applying a resin composition to the inner layer substrate and drying it as necessary, but is preferably formed using a resin sheet. The method of forming a resin composition layer using a resin sheet typically includes laminating the resin sheet and the inner layer substrate. The resin sheet and the inner layer substrate are laminated so that the resin composition layer of the resin sheet and the inner layer substrate are bonded. This lamination may be performed, for example, by thermocompression bonding the resin sheet to the inner layer substrate from the support side. Examples of a member for thermocompression bonding the resin sheet to the inner layer substrate (hereinafter also referred to as a "thermocompression bonding member") include a heated metal plate (such as a SUS panel) or a metal roll (such as a SUS roll). It is preferable to press the thermocompression bonding member not directly against the resin sheet but through an elastic material such as heat-resistant rubber so that the resin sheet can sufficiently conform to the surface irregularities of the inner layer substrate.

[0184] The lamination of the inner layer substrate and the resin sheet may be carried out by a vacuum lamination method. In the vacuum lamination method, the thermocompression temperature is preferably in the range of 60°C to 160°C, more preferably 80°C to 140°C, the thermocompression pressure is preferably in the range of 0.098MPa to 1.77MPa, more preferably 0.29MPa to 1.47MPa, and the thermocompression time is preferably in the range of 20 seconds to 400 seconds, more preferably 30 seconds to 300 seconds. The lamination is preferably carried out under reduced pressure conditions of 26.7hPa or less.

[0185] The lamination may be performed using a commercially available vacuum laminator, such as a vacuum pressure laminator manufactured by Meiki Seisakusho Co., Ltd., a vacuum applicator manufactured by Nikko Materials Co., Ltd., or a batch-type vacuum pressure laminator.

[0186] The method for manufacturing a circuit board may include smoothing the resin sheet after lamination under normal pressure (atmospheric pressure), for example, by pressing the resin sheet from the support side with a thermocompression member. The pressing conditions for the smoothing may be the same as those for the thermocompression bonding of the lamination. The smoothing may be performed using a commercially available laminator. The lamination and smoothing may be performed consecutively using the commercially available vacuum laminator.

[0187] The method for producing a circuit board according to this example includes a step (II) of curing the resin composition layer after the step (I). By curing the resin composition layer in the step (II), an insulating layer can be formed.

[0188] The resin composition layer is usually cured by thermal curing. The thermal curing conditions for the resin composition layer may vary depending on the type of resin composition. For example, the curing temperature is preferably 120°C to 240°C, more preferably 150°C to 220°C, and even more preferably 170°C to 210°C. The curing time is preferably 5 minutes to 120 minutes, more preferably 10 minutes to 100 minutes, and even more preferably 15 minutes to 100 minutes.

[0189] The method for producing a circuit board may include preheating the resin composition layer at a temperature lower than the curing temperature before thermally curing the resin composition layer. For example, prior to thermally curing the resin composition layer, the resin composition layer may be preheated for typically 5 minutes or more, preferably 5 minutes to 150 minutes, more preferably 15 minutes to 120 minutes, and even more preferably 15 minutes to 100 minutes, at a temperature of typically 50°C to 150°C, preferably 60°C to 140°C, and more preferably 70°C to 130°C. Preheating is typically carried out after step (I). Furthermore, when a smoothing treatment is carried out after laminating the inner layer substrate and the resin sheet, preheating can be carried out after the smoothing treatment.

[0190] When a resin sheet is used, the method for producing a circuit board may include a step of peeling off the support of the resin sheet after laminating the inner layer substrate and the resin sheet. The peeling off of the support may be performed between steps (I) and (II), or after step (II). Furthermore, when the method for producing a circuit board includes step (III) of forming holes in the insulating layer, step (IV) of roughening the insulating layer, and step (V) of forming a conductor layer, as described below, the peeling off of the support may be performed between steps (II) and (III), between steps (III) and (IV), or between steps (IV) and (V).

[0191] The method for producing a circuit board may include, after step (II), step (III) of forming holes such as via holes or through holes in the insulating layer. The method for forming the holes may be selected depending on factors such as the composition of the resin composition used to form the insulating layer. For example, holes may be formed by processing methods such as drilling, laser processing, and plasma processing, with laser processing being preferred. For example, holes may be formed by irradiating the insulating layer with laser light after peeling off the support, or by irradiating the insulating layer with laser light through the support. The dimensions and shape of the holes may be determined appropriately depending on the design of the circuit board.

[0192] The method for manufacturing a circuit board may include a step (IV) of roughening the insulating layer. The roughening treatment can roughen the surface of the insulating layer. The roughening treatment can also remove smears (resin residues) from the insulating layer. Therefore, this roughening treatment is sometimes called a "desmear treatment." For example, when holes are formed in step (III), smears may form in the holes. Therefore, it is preferable to perform the roughening treatment of step (IV) after step (III) to remove the smears.

[0193] The procedure and conditions for the roughening treatment are not particularly limited, and known procedures and conditions that are commonly used when forming an insulating layer for a circuit board may be adopted. For example, the roughening treatment may be performed by subjecting the insulating layer to a swelling treatment using a swelling liquid, an oxidation treatment using an oxidizing agent, and a neutralization treatment using a neutralizing liquid in this order.

[0194] Examples of swelling liquids used in the roughening treatment include alkaline solutions and surfactant solutions, with alkaline solutions being preferred. Examples of the alkaline solution include sodium hydroxide solution and potassium hydroxide solution. Examples of commercially available swelling liquids include "Swelling Dip Securigance P" and "Swelling Dip Securigance SBU" manufactured by Atotech Japan. Swelling treatment using a swelling liquid can be performed by immersing the insulating layer in the swelling liquid at 30°C to 90°C for 1 to 20 minutes. From the viewpoint of suppressing swelling of the resin in the insulating layer to an appropriate level, it is preferable to immerse the insulating layer in the swelling liquid at 40°C to 80°C for 5 to 15 minutes.

[0195] Examples of oxidizing agents used in the roughening treatment include alkaline permanganate solutions prepared by dissolving potassium permanganate or sodium permanganate in an aqueous solution of sodium hydroxide. Oxidation treatment using an oxidizing agent such as alkaline permanganate solution is preferably carried out by immersing the insulating layer in an oxidizing agent solution heated to 60°C to 100°C for 10 to 30 minutes. The concentration of permanganate in the alkaline permanganate solution is preferably 5% by mass to 10% by mass. Commercially available oxidizing agents include alkaline permanganate solutions such as "Concentrate Compact CP" and "Dosing Solution Securigance P" manufactured by Atotech Japan.

[0196] The neutralizing solution used in the roughening treatment is preferably an acidic aqueous solution, and a commercially available product such as "Reduction Solution Securigant P" manufactured by Atotech Japan can be cited as an example. Neutralization treatment using a neutralizing solution can be carried out by immersing the surface that has been oxidized with an oxidizing agent in a neutralizing solution at 30°C to 80°C for 5 to 30 minutes. From the standpoint of workability, a preferred method is to immerse the object that has been oxidized with an oxidizing agent in a neutralizing solution at 40°C to 70°C for 5 to 20 minutes.

[0197] The method for producing a circuit board may include step (V) of forming a conductor layer on the insulating layer. When the method for producing a circuit board includes step (III) or (IV), step (V) of forming a conductor layer is usually preferably carried out after steps (III) and (IV).

[0198] The conductive material used for the conductor layer is not particularly limited. In a preferred embodiment, the conductor layer contains one or more metals selected from the group consisting of gold, platinum, palladium, silver, copper, aluminum, cobalt, chromium, zinc, nickel, titanium, tungsten, iron, tin, and indium. The conductor layer may be a single metal layer or an alloy layer. Examples of alloy layers include layers formed from an alloy of two or more metals selected from the above group (e.g., nickel-chromium alloy, copper-nickel alloy, and copper-titanium alloy). Among these, from the viewpoints of versatility in forming the conductor layer, cost, ease of patterning, etc., single metal layers of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver, or copper, or alloy layers of nickel-chromium alloy, copper-nickel alloy, or copper-titanium alloy are preferred. Single metal layers of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver, or copper, or alloy layers of nickel-chromium alloy are more preferred, and single metal layers of copper are even more preferred.

[0199] The conductor layer may have a single layer structure or a multi-layer structure including two or more single metal or alloy layers made of different types of metals or alloys. When the conductor layer has a multi-layer structure, the layer in contact with the insulating layer is preferably a single metal layer of chromium, zinc, or titanium, or an alloy layer of a nickel-chromium alloy.

[0200] The thickness of the conductor layer depends on the design of the circuit board, but is preferably 3 μm to 35 μm, and more preferably 5 μm to 30 μm.

[0201] The conductor layer may be formed by plating. For example, a conductor layer having a desired wiring pattern can be formed by plating the surface of the insulating layer using a conventionally known technique such as a semi-additive method or a full-additive method. From the viewpoint of ease of production, the semi-additive method is preferred. An example of forming a conductor layer by a semi-additive method will be described below.

[0202] First, an electroless plated layer (plating seed layer) is formed on the surface of the insulating layer by electroless plating. Next, a mask pattern is formed on the formed electroless plated layer, exposing a portion of the electroless plated layer corresponding to the desired wiring pattern. After forming an electroless plated layer on the exposed electroless plated layer by electrolytic plating, the mask pattern is removed. Thereafter, unnecessary electroless plated layer is removed by etching, thereby forming a conductor layer having the desired wiring pattern.

[0203] As another example, the conductor layer may be formed using a metal foil. When a metal foil is used to form the conductor layer, step (V) is preferably performed between steps (I) and (II). For example, after step (I), the support is removed, and a metal foil is laminated on the exposed surface of the resin composition layer. The lamination of the resin composition layer and the metal foil may be performed by a vacuum lamination method. The lamination conditions may be the same as those described for step (I). Next, step (II) is performed to form an insulating layer. Thereafter, a conductor layer having a desired wiring pattern can be formed using the metal foil on the insulating layer by a known technique such as a subtractive method or a modified semi-additive method. The metal foil can be manufactured by a known method such as an electrolytic method or a rolling method. Commercially available metal foils include, for example, HLP foil and JXUT-III foil manufactured by JX Nippon Mining & Smelting Co., Ltd., and 3EC-III foil and TP-III foil manufactured by Mitsui Mining & Smelting Co., Ltd.

[0204] When a conductor layer is formed on an insulating layer, the method for manufacturing a circuit board may include performing an annealing treatment after the formation of the conductor layer. The annealing treatment can improve the adhesion between the insulating layer and the conductor layer. The annealing treatment can be performed, for example, by heating at 150°C to 210°C for 20 to 180 minutes.

[0205] In the method for manufacturing a circuit board, each of the above steps may be performed only once or may be repeated two or more times. For example, steps (I) to (V) may be performed repeatedly to form a circuit board having a multilayer structure, such as a multilayer printed wiring board having a plurality of insulating layers and conductor layers.

[0206] The method for manufacturing a circuit board may further include any optional steps in addition to the steps described above. For example, the method for manufacturing a circuit board may include a step of providing a semiconductor chip so that the semiconductor chip is bonded to the conductor layer. Specifically, when manufacturing a circuit board for a semiconductor chip package including a semiconductor chip, the method for manufacturing a circuit board may include a step of providing the semiconductor chip. The semiconductor chip may be bonded under appropriate conditions that allow conductive connection between the terminal electrodes of the semiconductor chip and the conductor layer formed on the insulating layer. For example, conditions used in flip-chip mounting may be employed. The semiconductor chip may be bonded via an insulating adhesive or by reflow bonding. If necessary, the provided semiconductor chip may be filled with a mold underfill material. The method for manufacturing a circuit board may also include, for example, a step of forming a sealing layer, a step of forming a solder resist layer, and a step of dicing the manufactured circuit board into individual pieces.

[0207] Examples of circuit boards include printed wiring boards and semiconductor chip packages. Examples of semiconductor chip packages include FC-CSP, MIS-BGA package, ETS-BGA package, fan-out type WLP (Wafer Level Package), fan-in type WLP, fan-out type PLP (Panel Level Package), and fan-in type PLP. In these semiconductor chip packages, it is preferable to form a rewiring formation layer using an insulating layer obtained by curing the above-mentioned resin composition layer. However, the circuit board is not limited to those exemplified here.

[0208] <Semiconductor device> The circuit board can be used to manufacture a semiconductor device. The semiconductor device includes the circuit board described above. Examples of the semiconductor device include various semiconductor devices used in electrical appliances (e.g., computers, mobile phones, smartphones, tablet devices, wearable devices, digital cameras, medical equipment, and televisions) and vehicles (e.g., motorcycles, automobiles, trains, ships, and aircraft). [Example]

[0209] The present invention will be specifically described below with reference to examples. However, the present invention is not limited to these examples. In the following description, "parts" and "%" representing amounts mean "parts by mass" and "% by mass", respectively, unless otherwise specified. Furthermore, the temperature and pressure conditions were room temperature (23°C) and atmospheric pressure (1 atm), unless otherwise specified.

[0210] <Synthesis Example 1: Synthesis of Polystyrene Resin B1> According to Example 1 of WO 2017 / 115813, 3.0 moles (390.6 g) of divinylbenzene, 1.8 moles (229.4 g) of ethylvinylbenzene, 10.2 moles (1066.3 g) of styrene, and 15.0 moles (1532.0 g) of n-propyl acetate were charged into a 5.0 L reactor, and 600 mmol of boron trifluoride diethyl ether complex was added at 70 °C. The reaction was allowed to proceed for 4 hours. The polymerization solution was terminated with aqueous sodium bicarbonate solution, and the oil layer was washed three times with pure water. The polymer was recovered by devolatilization under reduced pressure at 60 °C. The resulting polymer was weighed, confirming that 896.7 g of polystyrene resin B1 was obtained. The weight-average molecular weight (Mw) of polystyrene resin B1 was 41,300.

[0211] <Synthesis Example 2: Synthesis of Maleimide Resin C1> A methyl ethyl ketone solution (70% by mass of non-volatile components) of maleimide resin C1 synthesized by the method described in Synthesis Example 1 of Japan Institute of Invention and Innovation Technical Journal Publication No. 2020-500211 was prepared. This maleimide resin C1 has a structure represented by the following formula (C1).

[0212] [ka]

[0213] <Synthesis Example 3: Synthesis of Elastomer E1> A flask equipped with a stirrer, thermometer, and condenser was charged with 271.7 parts by mass of propylene glycol methyl ether acetate (PGMAc), 14.1 parts by mass (0.064 mol) of isophorone diisocyanate (IPDI), and 112.2 parts by mass (0.03 mol) of polybutadiene ("G-3000" manufactured by Nippon Soda Co., Ltd., hydroxyl value: 30 mg KOH / g) containing OH groups at both ends to obtain a mixed solution. The mixed solution was heated to 50°C and then maintained at this temperature for 1 hour. It was then confirmed that the amount of isocyanate groups was below a predetermined value. Then, 145.2 parts by mass (0.09 mol) of an oligophenylene ether resin containing phenolic hydroxyl groups at both ends (SABIC SA90-100, hydroxyl group equivalent: 807 g / mol) and 1 part by mass (0.003 mol) of benzophenone tetracarboxylic dianhydride (BTDA) were added to the mixed solution. The mixed solution was then heated to 140°C, and the reaction was continued for 4 hours. Characteristic absorption was measured by infrared spectroscopy, and the characteristic absorption of the isocyanate group at 2270 cm was confirmed. -1 The reaction was terminated when it was confirmed that the absorption peak had completely disappeared and the increase in viscosity had subsided. In this way, a solution of elastomer E1 (50% by mass of non-volatile components) was obtained as a polymer resin having a structure in which the molecular ends are capped with a phenolic resin (oligophenylene ether resin containing phenolic hydroxyl groups at both ends). The weight-average molecular weight Mw of elastomer E1 was 15,000.

[0214] <Synthesis Example 4: Synthesis of Polyimide Resin E2> A 500 mL separable flask was prepared, equipped with a water content receiver connected to a reflux condenser, a nitrogen inlet tube, and a stirrer. 20.3 g of 4,4'-oxydiphthalic anhydride (ODPA), 200 g of γ-butyrolactone, 20 g of toluene, and 29.6 g of 5-(4-aminophenoxy)-3-[4-(4-aminophenoxy)phenyl]-1,1,3-trimethylindane were added to the flask to obtain a reaction solution. The reaction was carried out at 45°C for 2 hours with stirring under a nitrogen stream. The reaction solution was then heated and maintained at approximately 160°C, during which condensed water was azeotropically removed with toluene under a nitrogen stream. It was confirmed that the specified amount of water had accumulated in the water content receiver and that no water was leaking out. After confirmation, the reaction solution was further heated and stirred at 200°C for 1 hour. The mixture was then cooled to obtain a polyimide resin solution (20% by mass of non-volatile components) containing polyimide resin E2 as a polymer resin having a 1,1,3-trimethylindane skeleton. The obtained polyimide resin E2 had a repeating unit represented by the following formula (e-1) and a repeating unit represented by the following formula (e-2). The weight-average molecular weight of the polyimide resin E2 was 12,000.

[0215] [ka]

[0216] <Synthesis Example 5: Synthesis of 1,2-bis(vinylphenyl)ethane (BVPE)> 1,2-Bis(vinylphenyl)ethane (BVPE) was synthesized as follows. A 500 ml three-neck flask was charged with 5.36 g (220 mmol) of granular magnesium for Grignard reaction (manufactured by Kanto Chemical Co., Ltd.), and equipped with a dropping funnel, a nitrogen inlet tube, and a septum cap. Under a nitrogen stream, the entire system was heated and dehydrated in a dryer while stirring the magnesium granules with a stirrer.

[0217] 300 ml of dry tetrahydrofuran was placed in a syringe and poured into the flask through the septum cap. After the solution was cooled to -5°C, 30.5 g (200 mmol) of vinylbenzyl chloride (VBC, manufactured by Tokyo Chemical Industry Co., Ltd.) was added dropwise using a dropping funnel over approximately 4 hours. After the dropwise addition was completed, stirring was continued at 0°C for 20 hours. After the reaction was completed, the reaction solution was filtered to remove any remaining magnesium and concentrated using an evaporator.

[0218] The concentrated reaction solution was diluted with hexane, washed once with 3.6% aqueous hydrochloric acid, washed three times with purified water, and then dehydrated with magnesium sulfate. The dehydrated reaction solution was purified by passing it through a short column of silica gel (Wakogel C300, Fujifilm Wako Pure Chemical Industries, Ltd.) / hexane and then vacuum dried to obtain BVPE. The obtained BVPE was a mixture of mm (liquid), mp (liquid), and pp (crystalline) forms, with a yield of 90%. 1 The structure was investigated by H-NMR, and the values ​​were consistent with those in the literature (6H-vinyl: α-2H, 6.7, β-4H, 5.7, 5.2; 8H-aromatic: 7.1-7.35; 4H-methylene: 2.9).

[0219] <Production Example 1: Production of Silica 1 Surface-Treated with a Radical-Reactive Silane Coupling Agent> Spherical silica (average particle size 0.5 μm, specific surface area 5.8 m 2 100 parts by mass of silica 1 (10 ...

[0220] <Production Example 2: Production of Silica 2 Surface-Treated with a Radical-Reactive Silane Coupling Agent> Silica 2 surface-treated with an allyl-based silane coupling agent was produced in the same manner as in Production Example 1, except that 0.6 parts by mass of an allyl-based silane coupling agent (7-octenyltrimethoxysilane, "KBM-1083", manufactured by Shin-Etsu Chemical Co., Ltd.) was used instead of 0.6 parts by mass of a methacrylic silane coupling agent ("KBM-5803", manufactured by Shin-Etsu Chemical Co., Ltd.) as the radical-reactive silane coupling agent. The amount of the allyl-based silane coupling agent used for surface treatment of silica 2 was 0.6% by mass.

[0221] <Production Example 3: Production of Silica 3 Surface-Treated with Radical-Reactive Silane Coupling Agent> Silica 3 surface-treated with a styryl silane coupling agent was produced in the same manner as in Production Example 1, except that 0.6 parts by mass of a styryl silane coupling agent (p-styryltrimethoxysilane, "KBM-1403", manufactured by Shin-Etsu Chemical Co., Ltd.) was used instead of 0.6 parts by mass of a methacrylic silane coupling agent ("KBM-5803", manufactured by Shin-Etsu Chemical Co., Ltd.) as the radical-reactive silane coupling agent. The amount of the styryl silane coupling agent on the surface of silica 3 was 0.6% by mass.

[0222] <Production Example 4: Production of Silica 4 Surface-Treated with Radical-Reactive Silane Coupling Agent> Silica 4 surface-treated with a methacrylic silane coupling agent was produced in the same manner as in Production Example 1, except that 0.5 parts by mass of a methacrylic silane coupling agent ("KBM-503" manufactured by Shin-Etsu Chemical Co., Ltd., 3-methacryloxypropyltrimethoxysilane) was used instead of 0.6 parts by mass of a methacrylic silane coupling agent ("KBM-5803" manufactured by Shin-Etsu Chemical Co., Ltd.) as the radical-reactive silane coupling agent. The amount of the methacrylic silane coupling agent on the surface of silica 4 was 0.5% by mass.

[0223] <Production Example 5: Production of Silica 5 Surface-Treated with Radical-Reactive Silane Coupling Agent> Silica particles ("SC-2050-SVJ" manufactured by Admatechs Co., Ltd.) surface-treated with a silane coupling agent having a vinyl group as a radical reactive silane coupling agent were prepared as silica 5. The average particle diameter of silica 5 was 0.5 μm and the specific surface area was 5.8 m. 2 / g, and the amount of the surface treatment of the silica 5 with the vinyl-based silane coupling agent was 1.0 mass %.

[0224] <Production Example 6: Production of Silica 6 Surface-Treated with an Arbitrary Surface Treatment Agent> Silica 6 surface-treated with an amine-based silane coupling agent was produced in the same manner as in Production Example 1, except that 0.6 parts by mass of an amine-based silane coupling agent ("KBM-573" manufactured by Shin-Etsu Chemical Co., Ltd.) was used instead of 0.6 parts by mass of a methacrylic silane coupling agent ("KBM-5803" manufactured by Shin-Etsu Chemical Co., Ltd.). The amount of the amine-based silane coupling agent used for surface treatment of silica 6 was 0.6% by mass.

[0225] <Examples 1 to 18 and Comparative Examples 1 to 6. Production of Resin Varnish> The components were weighed and mixed in the amounts (parts by mass) shown in the table below, and then 10 parts by mass of methyl ethyl ketone and 10 parts by mass of cyclohexanone were added and uniformly dispersed using a high-speed rotating mixer to obtain a resin varnish as a liquid resin composition. The details of each component shown in the table below are as follows.

[0226] (A) Radical reactive silane coupling agent KBM-5803: Methacrylic silane coupling agent (Shin-Etsu Chemical Co., Ltd., molecular weight 318)

[0227] (D-1) Specially treated inorganic filler (inorganic filler surface-treated with a radical reactive silane coupling agent): Silica 1: Silica 1 produced in Production Example 1. Amount of surface treatment with methacrylic silane coupling agent: 0.6% by mass Silica 2: Silica 2 produced in Production Example 2. Amount of surface treatment with allyl silane coupling agent: 0.6% by mass Silica 3: Silica 3 produced in Production Example 3. Amount of surface treatment with styryl silane coupling agent: 0.6% by mass Silica 4: Silica 4 produced in Production Example 4. Amount of surface treatment with methacrylic silane coupling agent: 0.5% by mass Silica 5: Spherical silica treated with a vinyl-based silane coupling agent ("SC-2050-SVJ" manufactured by Admatechs Co., Ltd.) as described in Production Example 5. The amount of surface treatment with the vinyl-based silane coupling agent was 1.0% by mass.

[0228] (D-2) Optional inorganic filler (inorganic filler not surface-treated with a radical reactive silane coupling agent): Silica 6: Silica 6 produced in Production Example 6. Amount of surface treatment with an amine-based silane coupling agent: 0.6 mass %.

[0229] (B) Specific polystyrene materials: PX-3-RP-61: Polystyrene resin containing oxazoline groups, manufactured by Nippon Shokubai Co., Ltd., weight average molecular weight 25,000. Polystyrene B1: toluene solution containing 50% by mass of nonvolatile components, polystyrene resin B1 synthesized in Synthesis Example 1, weight average molecular weight 41,000. XPA-8272: Polystyrene resin containing acryloyl groups, n-butyl acetate solution with 60% non-volatile content, manufactured by Mitsui Chemicals, Inc., weight average molecular weight 12,000. EF-40: Polystyrene resin containing acid anhydride groups, manufactured by CRAY VALLEY, weight average molecular weight 11,000. SEP-03T: Polystyrene particles, manufactured by Negami Chemical Industrial Co., Ltd., average particle size 0.3 μm.

[0230] (B') Any polystyrene material: G100C: Polystyrene resin, manufactured by Toyo Styrene Co., Ltd., weight average molecular weight 150,000 BVPE: BVPE synthesized in Synthesis Example 5, molecular weight 234 SX-500H: Polystyrene particles, manufactured by Soken Chemical & Engineering Co., Ltd., average particle size 5.0 μm

[0231] (C) Radical reactive resin: Maleimide C1: Maleimide resin having an indane skeleton, maleimide group equivalent weight 428 g / eq., maleimide resin C1 synthesized in Synthesis Example 2 (non-volatile components 70 mass %). MIR-5000-60MT: Maleimide resin with isopropylidene groups, maleimide group equivalent weight 266 g / eq., toluene solution with 60% non-volatile content, manufactured by Nippon Kayaku Co., Ltd. SLK-6895-T90: Maleimide resin with a carbon skeleton derived from dimer acid, maleimide group equivalent weight 345 g / eq., toluene solution with 90% non-volatile content, manufactured by Shin-Etsu Chemical Co., Ltd. OPE-2St: Vinylbenzyl-modified polyphenylene ether, functional group equivalent weight 590 g / eq., toluene solution with 65% non-volatile content, manufactured by Mitsubishi Gas Chemical Co., Ltd. NEV-1100-70T: Resin containing aromatic rings and radically polymerizable unsaturated groups, toluene solution with 70% non-volatile content, manufactured by Mitsubishi Chemical Corporation A-DOG: Dioxane acrylic monomer, (meth)acryloyl group equivalent 163g / eq., manufactured by Shin-Nakamura Chemical Co., Ltd.

[0232] (E) Thermoplastic resin: Elastomer E1: Elastomer E1 synthesized in Synthesis Example 3 (non-volatile components: 50% by mass) YX7553BH30: Phenoxy resin, 1:1 solution of MEK and cyclohexanone with 30% non-volatile content, manufactured by Mitsubishi Chemical Corporation Polyimide E2: Polyimide resin E2 synthesized in Synthesis Example 4 (non-volatile component 20% by mass)

[0233] (F) Thermosetting resin: ·ALP-d: Benzoxazine resin, active group equivalent 257g / eq., manufactured by Shikoku Kasei Kogyo Co., Ltd. ZX-1059: Epoxy resin (a 1:1 mixture of bisphenol A epoxy resin and bisphenol F epoxy resin), epoxy equivalent weight approximately 169g / eq., manufactured by Nippon Steel Chemical & Material Co., Ltd. LA-3018-50P: Phenolic resin, active group equivalent weight 151g / eq., 1-methoxy-2-propanol solution containing 50% non-volatile matter by mass, manufactured by DIC Corporation

[0234] (G) Polymerization initiator: Perhexyl D: Peroxide radical polymerization initiator, di-tert-hexyl peroxide, manufactured by NOF Corporation

[0235] (H) Curing accelerator: 1B2PZ: 1-benzyl-2-phenylimidazole, manufactured by Shikoku Chemicals Corporation

[0236] <Method of manufacturing resin sheet A> A polyethylene terephthalate film ("AL5" manufactured by Lintec Corporation, thickness 38 μm) with a release layer was prepared as a support. The resin varnishes obtained in the Examples and Comparative Examples were uniformly applied onto the release layer of this support so that the thickness of the resin composition layer after drying would be 40 μm. The applied resin varnish was then dried at 80°C to 100°C (average 90°C) for 2 minutes to obtain a resin sheet A including a support and a resin composition layer.

[0237] <Test 1. Measurement test of minimum melt viscosity of resin composition> Twenty-five resin composition layers of resin sheet A were stacked to obtain a 1 mm thick resin sample layer. This resin sample layer was punched out to a diameter of 20 mm to obtain a measurement sample. The dynamic viscoelastic modulus of the obtained measurement sample was measured using a dynamic viscoelasticity measuring device (UBM "Rheogel-G3000") under measurement conditions of a starting temperature of 60°C to 200°C, a heating rate of 5°C / min, a measurement temperature interval of 2.5°C, and an oscillation frequency of 1 Hz, and the minimum melt viscosity was determined.

[0238] <Test 2. Measurement test of dielectric dissipation factor (Df) and mean coefficient of linear thermal expansion (CTE)> (1) Preparation of cured product: Resin sheet A was heated in an oven at 190° C. for 90 minutes to cure the resin composition layer. The resin sheet was taken out of the oven and the support was peeled off to obtain a cured product B of the resin composition layer.

[0239] (2) Measurement of dielectric loss tangent (Df): Cured product B was cut into a piece 80 mm long and 2 mm wide to obtain a test piece. The dielectric loss tangent (Df value) of the test piece was measured by the cavity resonance perturbation method using a measuring device (Agilent Technologies "HP8362B") at a measurement frequency of 5.8 GHz and a measurement temperature of 23°C. Measurements were performed on two test pieces, and the average was calculated.

[0240] (3) Measurement of the mean coefficient of linear expansion (CTE): Cured product B was cut into a piece approximately 5 mm wide and 15 mm long to obtain a test specimen. This test specimen was subjected to thermomechanical analysis using a thermomechanical analyzer (Rigaku Corporation, "Thermo Plus TMA8310") by the tensile load method. In this thermomechanical analysis, the test specimen was mounted in the analyzer, and the thermal expansion coefficient (ppm) was measured twice consecutively under the following conditions: a load of 1 g and a heating rate of 5°C / min. The first measurement was performed by raising the temperature to 200°C, and the second measurement was performed by raising the temperature to 260°C. The average linear expansion coefficient (ppm / °C) was calculated from the thermal expansion coefficient measured from 25°C to 150°C in the second measurement.

[0241] <Test 3. Evaluation test of adhesion to conductor layer> (1) Copper foil surface preparation: The shiny side of an electrolytic copper foil (Mitsui Mining & Smelting Co., Ltd., "3EC-III," 35 μm thick) was etched to a depth of 1 μm with a microetching agent (Mec Co., Ltd., "CZ8101") to roughen the copper surface, followed by a rust-proofing treatment (CL8300). The copper foil whose surface had been etched with the microetching agent in this manner is hereinafter sometimes referred to as "CZ copper foil." Furthermore, this copper foil was heat-treated in an oven at 130°C for 30 minutes to obtain copper foil I having a roughened treated surface.

[0242] (2) Preparation of inner layer board: A glass cloth-based epoxy resin double-sided copper-clad laminate (copper foil thickness 18 μm, substrate thickness 0.4 mm, Panasonic "R1515A") with copper foil on the surface and inner layer circuitry was prepared. Both sides of this glass cloth-based epoxy resin double-sided copper-clad laminate were etched to a depth of 1 μm using a microetching agent (MEC "CZ8101") to roughen the copper foil surface. This resulted in an inner layer substrate with a treated CZ copper foil on its surface.

[0243] (3) Lamination of resin composition layer: Resin sheet A was laminated on both sides of the inner layer substrate. This lamination was performed using a batch-type vacuum pressure laminator (Nikko Materials Co., Ltd., two-stage build-up laminator "CVP700") so that the resin composition layer was in contact with the inner layer substrate. The lamination was performed by reducing the pressure for 30 seconds to 13 hPa or less, followed by pressure bonding at 120°C and a pressure of 0.74 MPa for 30 seconds. The laminated resin sheet A was then heat-pressed at 100°C and a pressure of 0.5 MPa for 60 seconds. The support was then peeled off to expose the resin composition layer.

[0244] (4) Lamination of copper foil and curing of resin composition layer: The treated surface of copper foil I was laminated onto the exposed resin composition layer under the same conditions as in "(3) Lamination of Resin Composition Layer" above. The resin composition layer was then cured at 200°C for 90 minutes to form an insulating layer as a cured product of the resin composition. Through these operations, evaluation substrate C was obtained, in which CZ copper foil was laminated on both sides of the insulating layer. This evaluation substrate C had a layer structure of copper foil I / insulating layer / inner layer substrate / insulating layer / copper foil I.

[0245] (5) Copper foil peel strength measurement: Evaluation board C was cut into small pieces measuring 150 mm x 30 mm. A cutter was used to cut a small copper foil I piece, enclosing a rectangular area 10 mm wide and 100 mm long. One end of this rectangular area was peeled off and gripped with the gripper of a tensile tester (TSE Autocom Universal Tester AC-50C-SL). The copper foil was pulled vertically at a rate of 50 mm / min at room temperature (25°C), and the load [kgf / cm] required to peel off 35 mm was measured as the copper foil peel strength. The higher the copper foil peel strength, the better the adhesion of the insulating layer to the conductor layer corresponding to the copper foil. Measurements were performed in accordance with Japanese Industrial Standard JIS C6481.

[0246] (6) Measurement of copper foil peel strength after HAST: An accelerated environmental test was performed on the evaluation substrate C using a highly accelerated life tester ("PM422" manufactured by Kusumoto Chemicals Co., Ltd.) in which the evaluation substrate C was exposed to an environment of 130°C temperature and 85% RH for 100 hours. Thereafter, the copper foil peel strength was measured using the same procedure as in "(5) Measurement of copper foil peel strength" above.

[0247] <Result> The results of the Examples and Comparative Examples are shown in the following table. In the table, the abbreviations have the following meanings: NVC: Non-volatile content Df: Dielectric loss tangent CTE: Coefficient of mean linear thermal expansion Adhesion before HAST: Copper foil peel strength before HAST Adhesion after HAST: Copper foil peel strength after HAST

[0248] [Table 1]

[0249] [Table 2]

[0250] [Table 3]

[0251]

Table 4

Claims

1. (A) a silane coupling agent having a radical-reactive functional group; (B) one or more polystyrene materials selected from the group consisting of polystyrene resins having a weight-average molecular weight of 1,000 to 100,000 and polystyrene particles having an average particle size of 3 μm or less; (C) a radical reactive resin, and (D) an inorganic filler; A resin composition, wherein the amount of component (D) is 70% by mass or more relative to 100% by mass of nonvolatile components in the resin composition.

2. The resin composition according to claim 1, wherein the amount of component (A) is 0.01% by mass or more and 5% by mass or less, based on 100% by mass of nonvolatile components in the resin composition.

3. The resin composition according to claim 1, wherein the component (D) comprises (D-1) an inorganic filler that has been surface-treated with the component (A).

4. The resin composition according to claim 3, wherein the amount of the surface treatment of the component (D-1) with the component (A) is 0.1% by mass or more and 3.0% by mass or less.

5. The resin composition according to claim 1, wherein the amount of the component (B) is 0.1% by mass or more and 40% by mass or less, based on 100% by mass of the resin components in the resin composition.

6. The resin composition according to claim 1, wherein the component (C) comprises at least one selected from the group consisting of a maleimide resin, a styryl resin, a (meth)acrylic resin, and an allyl resin.

7. The resin composition according to claim 1 , further comprising (E) a polymer resin.

8. The resin composition according to claim 7, wherein the amount of the component (E) is 1% by mass or more and 15% by mass or less, based on 100% by mass of the resin components in the resin composition.

9. With or without epoxy resin; The resin composition according to claim 1, wherein the amount of the epoxy resin is 3% by mass or less based on 100% by mass of nonvolatile components in the resin composition.

10. The resin composition according to claim 1, having a minimum melt viscosity of 5,000 poise or less.

11. The resin composition according to claim 1, which is used to form an insulating layer of a circuit board.

12. A method for producing the resin composition according to claim 1, comprising: A method for producing a resin composition, comprising the step of mixing (A) a silane coupling agent having a radical-reactive functional group, (B) one or more polystyrene materials selected from the group consisting of a polystyrene resin having a weight-average molecular weight of 1,000 to 100,000 and polystyrene particles having an average particle size of 3 μm or less, (C) a radical-reactive resin, and (D) an inorganic filler.

13. A method for producing the resin composition according to claim 3, comprising: (A) a silane coupling agent having a radical-reactive functional group is mixed with (D') an inorganic filler before surface treatment to obtain (D-1) an inorganic filler surface-treated with component (A); a step of mixing component (D-1), (B) one or more polystyrene materials selected from the group consisting of polystyrene resins having a weight average molecular weight of 1,000 to 100,000 and polystyrene particles having an average particle size of 3 μm or less, and (C) a radical-reactive resin; A method for producing a resin composition, comprising:

14. A support and a resin composition layer provided on the support, A resin sheet, wherein the resin composition layer comprises the resin composition according to any one of claims 1 to 11.

15. A cured product of the resin composition according to any one of claims 1 to 11.

16. A circuit board comprising a cured product of the resin composition according to any one of claims 1 to 11.

17. A semiconductor device comprising the circuit board according to claim 16.

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