Thermosetting resin compositions, prepregs, resin films, laminates, printed wiring boards, and semiconductor packages

Abstract

To provide a thermosetting resin composition which can improve a dielectric loss tangent (Df), and a prepreg, a resin film, a laminated plate, a printed wiring board and a semiconductor package, which are obtained by using the thermosetting resin composition.SOLUTION: A thermosetting resin composition contains (A) a thermosetting resin and (B) an inorganic filler, wherein (B) the inorganic filler has D10 / D50 of 0.70 or more, when a particle diameter corresponding to cumulative 10 vol.% is represented by D10 and a particle diameter corresponding to cumulative 50 vol.% is represented by D50, from the small particle diameter side in a particle cumulative particle size distribution.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to a thermosetting resin composition, a prepreg, a resin film, a laminate, a printed wiring board, and a semiconductor package. [Background technology]

[0002] The speed and capacity of signals used in various electronic devices, such as mobile communication devices typified by mobile phones, their base station equipment, network infrastructure devices such as servers and routers, and mainframe computers, are increasing year by year. Accordingly, the printed wiring boards used in these electronic devices must be able to handle higher frequencies, and there is a demand for substrate materials with a low dielectric loss tangent (Df) in high-frequency bands that can reduce transmission loss. In recent years, in addition to the electronic devices mentioned above, new systems using high-frequency wireless signals have been put into practical use or are planned for use in the fields of ITS (Intelligent Transport Systems), such as automobiles and transportation systems, and indoor short-range communications. Low-transmission-loss substrate materials are also required for the printed wiring boards used in these devices.

[0003] Conventionally, thermoplastic polymers with small dielectric dissipation factor (Df) have been used for printed wiring boards that require low transmission loss. For example, a method of using polyphenylene ether as a thermoplastic polymer in combination with a thermosetting resin is known. Specifically, a resin composition containing polyphenylene ether and an epoxy resin (see, for example, Patent Document 1) is known. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 58-069046 Summary of the Invention [Problem to be solved by the invention]

[0005] However, increasing the content of thermoplastic polymer in a thermosetting resin composition to further reduce the dielectric loss tangent (Df) has adverse effects such as a decrease in heat resistance, moldability, and processability, and it has not been easy to further reduce the dielectric loss tangent (Df) without adversely affecting other properties of the thermosetting resin composition.

[0006] In view of the current situation, the present disclosure aims to provide a thermosetting resin composition capable of improving the dielectric loss tangent (Df), as well as to provide a prepreg, a resin film, a laminate, a printed wiring board, and a semiconductor package obtainable using the thermosetting resin composition. [Means for solving the problem]

[0007] As a result of extensive research, the present inventors have found that the thermosetting resin composition of the present disclosure can achieve the above object.

[0008] The present disclosure includes the following [1] to

[13] . [1] A thermosetting resin composition containing (A) a thermosetting resin and (B) an inorganic filler, The thermosetting resin composition is such that the (B) inorganic filler has a D10 / D50 ratio of 0.70 or more, where D10 is the particle diameter corresponding to the smallest 10% by volume of the particles in a cumulative particle size distribution, and D50 is the particle diameter corresponding to the smallest 50% by volume of the particles. [2] The thermosetting resin composition according to the above [1], wherein, in the inorganic filler (B), when the particle diameter corresponding to the cumulative 90% by volume of particles having smallest particle diameters in the cumulative particle size distribution of the particles is represented as D90, D90 / D50 is 1.80 or less. [3] The thermosetting resin composition according to the above [1] or [2], wherein the inorganic filler (B) has a D50 of 0.50 to 5 μm. [4] The thermosetting resin composition according to any one of the above [1] to [3], wherein the content of the (B) inorganic filler is 5 to 95 mass % based on the total solid content in the thermosetting resin composition. [5] The thermosetting resin composition according to any one of the above [1] to [4], wherein the (A) thermosetting resin comprises at least one selected from the group consisting of an epoxy resin, a maleimide compound, a polyphenylene ether resin, a phenolic resin, a polyimide resin, a cyanate resin, an isocyanate resin, a benzoxazine resin, an oxetane resin, an amino resin, an unsaturated polyester resin, an allyl resin, a dicyclopentadiene resin, a silicone resin, a triazine resin, and a melamine resin. [6] The thermosetting resin composition according to any one of the above [1] to [5], further comprising (C) an elastomer. [7] The thermosetting resin composition according to any one of the above [1] to [6], further comprising (D) a modified conjugated diene polymer. [8] The thermosetting resin composition according to any one of the above [1] to [7], further comprising (E) a curing accelerator. [9] A prepreg containing the thermosetting resin composition according to any one of the above [1] to [8] or a semi-cured product of the thermosetting resin composition.

[10] A resin film containing the thermosetting resin composition according to any one of the above [1] to [8] or a semi-cured product of the thermosetting resin composition.

[11] A laminate comprising a cured product of the thermosetting resin composition according to any one of the above [1] to [8] or a cured product of the prepreg according to the above [9], and a metal foil.

[12] A printed wiring board comprising one or more members selected from the group consisting of a cured product of the thermosetting resin composition according to any one of [1] to [8] above, a cured product of the prepreg according to [9] above, and a laminate according to

[11] above.

[13] A semiconductor package comprising the printed wiring board according to

[12] above and a semiconductor element. [Effects of the Invention]

[0009] The present disclosure provides a thermosetting resin composition that can improve the dielectric loss tangent (Df), as well as a prepreg, a resin film, a laminate, a printed wiring board, and a semiconductor package that are obtained using the thermosetting resin composition. DETAILED DESCRIPTION OF THE INVENTION

[0010] In the numerical ranges described in this specification, the upper or lower limit of the numerical range may be replaced with the values ​​shown in the examples. Furthermore, the lower and upper limits of a numerical range can be arbitrarily combined with the lower or upper limit of another numerical range. In the expression "AA to BB," the numerical values ​​AA and BB at the ends are included as the lower and upper limits, respectively, of the numerical range. In this specification, for example, the expression "10 or more" means 10 or a numerical value exceeding 10, and this also applies when the numerical values ​​are different. Furthermore, for example, the expression "10 or less" means 10 or a numerical value less than 10, and this also applies when the numerical values ​​are different. Furthermore, unless otherwise specified, each component and material exemplified in this specification may be used alone or in combination of two or more. In this specification, the content of each component in a composition means the total amount of the multiple substances present in the composition when multiple substances corresponding to each component are present in the composition, unless otherwise specified.

[0011] In this specification, the term "resin component" refers to all components of the solid content constituting the resin composition, excluding inorganic compounds such as inorganic fillers, which will be described later. In this specification, the term "solid content" refers to components in a resin composition other than volatile substances (such as water and the solvent described below). In other words, the solid content includes not only those that are solid at room temperature around 25° C., but also those that are liquid, syrup-like, or wax-like at room temperature around 25° C. The expression "containing" used in this specification means both simply containing and containing the component described in the component in a reacted state. Any combination of the descriptions in this specification is also included in the present disclosure and the present embodiment.

[0012] [Thermosetting resin composition] The thermosetting resin composition of this embodiment is as follows. A thermosetting resin composition containing (A) a thermosetting resin (hereinafter, sometimes referred to as component (A)) and (B) an inorganic filler (hereinafter, sometimes referred to as component (B)), The thermosetting resin composition is such that the (B) inorganic filler has a D10 / D50 ratio of 0.70 or more, where D10 is the particle diameter corresponding to the smallest 10% by volume of the particles in a cumulative particle size distribution, and D50 is the particle diameter corresponding to the smallest 50% by volume of the particles. According to the thermosetting resin composition of this embodiment, the dielectric loss tangent (Df) can be further reduced without adversely affecting other properties of the thermosetting resin composition, as will be described in detail later. The components contained in the thermosetting resin composition of this embodiment will be described in detail below.

[0013] ((A) Thermosetting resin) Examples of component (A) include epoxy resins, maleimide compounds, polyphenylene ether resins, phenolic resins, polyimide resins, cyanate resins, isocyanate resins, benzoxazine resins, oxetane resins, amino resins, unsaturated polyester resins, allyl resins, dicyclopentadiene resins, silicone resins, triazine resins, melamine resins, etc. Among these, component (A) preferably contains at least one selected from the group consisting of epoxy resins, maleimide compounds, polyphenylene ether resins, phenolic resins, polyimide resins, cyanate resins, and isocyanate resins, more preferably contains at least one selected from the group consisting of epoxy resins and maleimide compounds, and even more preferably contains a maleimide compound from the viewpoint of low thermal expansion, etc. As the component (A), one type may be used alone, or two or more types may be used in combination.

[0014] The epoxy resin is preferably an epoxy resin having two or more epoxy groups in one molecule. Here, epoxy resins are classified into glycidyl ether type epoxy resins, glycidyl amine type epoxy resins, glycidyl ester type epoxy resins, etc. Among these, glycidyl ether type epoxy resins are preferred. Epoxy resins are classified into various epoxy resins depending on the main skeleton, and each of the above types of epoxy resins can be further classified into bisphenol-type epoxy resins such as bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, and bisphenol S-type epoxy resins; alicyclic epoxy resins such as dicyclopentadiene-type epoxy resins; aliphatic linear epoxy resins; novolac-type epoxy resins such as phenol novolac-type epoxy resins, cresol novolac-type epoxy resins, bisphenol A novolac-type epoxy resins, bisphenol F novolac-type epoxy resins, phenol aralkyl novolac-type epoxy resins, and biphenyl aralkyl novolac-type epoxy resins; stilbene-type epoxy resins; naphthalene-type epoxy resins such as naphthol novolac-type epoxy resins and naphthol aralkyl-type epoxy resins; biphenyl-type epoxy resins; xylylene-type epoxy resins; and dihydroanthracene-type epoxy resins.

[0015] The maleimide compound preferably includes at least one selected from the group consisting of maleimide compounds having one or more (preferably two or more) N-substituted maleimide groups and derivatives thereof. The maleimide compound having one or more N-substituted maleimide groups is not particularly limited, and examples thereof include aromatic maleimide compounds preferably having one N-substituted maleimide group bonded to an aromatic ring, such as N-phenylmaleimide, N-(2-methylphenyl)maleimide, N-(4-methylphenyl)maleimide, N-(2,6-dimethylphenyl)maleimide, N-(2,6-diethylphenyl)maleimide, N-(2-methoxyphenyl)maleimide, and N-benzylmaleimide; 4,4'-diphenylmethane bismaleimide, bis(4-maleimidophenyl)ether, bis(4-maleimidophenyl)sulfone, 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethane bismaleimide, 4-methyl-1 aromatic bismaleimide compounds preferably having two N-substituted maleimide groups bonded to an aromatic ring, such as 3-phenylene bismaleimide, m-phenylene bismaleimide, 2,2-bis[4-(4-maleimidophenoxy)phenyl]propane, and indane ring-containing aromatic bismaleimides; aromatic polymaleimide compounds preferably having three or more N-substituted maleimide groups bonded to an aromatic ring, such as polyphenylmethane maleimide and biphenyl aralkyl maleimide; and aliphatic maleimide compounds such as N-dodecylmaleimide, N-isopropylmaleimide, and N-cyclohexylmaleimide, 1,6-bismaleimide-(2,2,4-trimethyl)hexane, and pyrrolidine acid binder-type long-chain alkyl bismaleimides. Among these, from the viewpoints of compatibility with other resins, adhesion to conductors, heat resistance, low thermal expansion, mechanical properties, and dielectric loss tangent (Df), aromatic bismaleimide compounds having two N-substituted maleimide groups bonded to an aromatic ring are more preferred, and 4,4'-diphenylmethane bismaleimide and indane ring-containing aromatic bismaleimide are even more preferred.

[0016] Examples of the derivatives of maleimide compounds include addition reaction products of a maleimide compound having one or more (preferably two or more) N-substituted maleimide groups with an amine compound such as a monoamine compound or a diamine compound. Examples of the monoamine compounds include monoamine compounds having an acidic substituent, such as o-aminophenol, m-aminophenol, p-aminophenol, o-aminobenzoic acid, m-aminobenzoic acid, p-aminobenzoic acid, o-aminobenzenesulfonic acid, m-aminobenzenesulfonic acid, p-aminobenzenesulfonic acid, 3,5-dihydroxyaniline, and 3,5-dicarboxyaniline. Examples of the diamine compound include 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylethane, 4,4'-diaminodiphenylpropane, 2,2'-bis(4,4'-diaminodiphenyl)propane, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, 3,3'-diethyl-4,4'-diaminodiphenylmethane, 3,3'-dimethyl-4,4'-diaminodiphenylethane, 3,3'-diethyl-4,4'-diaminodiphenylethane, 4,4'-diaminodiphenyl ether, Examples of the alkyl esters include 4,4'-diaminodiphenyl thioether, 3,3'-dihydroxy-4,4'-diaminodiphenylmethane, 2,2',6,6'-tetramethyl-4,4'-diaminodiphenylmethane, 3,3'-dichloro-4,4'-diaminodiphenylmethane, 3,3'-dibromo-4,4'-diaminodiphenylmethane, 2,2',6,6'-tetrachloro-4,4'-diaminodiphenylmethane, 2,2',6,6'-tetrabromo-4,4'-diaminodiphenylmethane, and siloxane diamine.

[0017] (Content of component (A)) The content of the thermosetting resin (A) in the thermosetting resin composition of the present embodiment is not particularly limited, but from the viewpoints of heat resistance and moldability, it is preferably 5 to 95 mass %, more preferably 10 to 80 mass %, even more preferably 10 to 60 mass %, and particularly preferably 15 to 40 mass %, relative to the total solid content in the thermosetting resin composition.

[0018] ((B) Inorganic filler) (B) When the particle diameter corresponding to the cumulative 10% by volume from the smallest particle diameter in the cumulative particle size distribution of particles is expressed as D10 and the particle diameter corresponding to the cumulative 50% by volume is expressed as D50, the inorganic filler has a D10 / D50 (ratio of D10 to D50) of 0.70 or more. A D10 / D50 of 0.70 or more means that the particle diameter at D10 and the particle diameter at D50 are close to each other, and therefore the peak in the particle "frequency distribution" (volume basis) is sharp rather than broad, meaning that the width of the peak is narrow.

[0019] The thermosetting resin composition of this embodiment, containing an inorganic filler with a D10 / D50 ratio of 0.70 or greater as component (B), enables a reduction in the dielectric loss tangent (Df) while maintaining the properties of the other components. The reason for this effect is presumed to be as follows: As the particle size distribution of the inorganic filler narrows, the number of particles with small particle sizes (e.g., particles with a D30 or less) decreases, resulting in a reduction in particles with large specific surface areas. This leads to (1) a reduction in the "interface" between the inorganic filler and the resin component, which is thought to be the cause of an increase in the dielectric loss tangent (Df), or (2) a reduction in the amount of surface treatment agent (coupling agent) on the surface of the inorganic filler, which is thought to be the cause of an increase in the dielectric loss tangent (Df), resulting in a lower dielectric loss tangent (Df). Note that D30 refers to the particle size corresponding to the smallest 30% by volume of the particles in the cumulative particle size distribution. However, the validity of this presumption does not affect the scope of the present invention. From the above viewpoints, D10 / D50 is preferably 0.72 or more, and more preferably 0.74 or more. The upper limit of D10 / D50 is not particularly limited, but is 1.00 or less, and may be 0.90 or less, 0.80 or less, or 0.78 or less. In other words, D10 / D50 is preferably 0.70 to 1.00, and the preferred lower and upper limits are as described above. From the above viewpoints, D10 is preferably 0.30 μm or more, more preferably 0.40 μm or more, and even more preferably 0.45 μm or more. It may be 0.50 μm or more, 0.60 μm or more, 0.65 μm or more, 0.80 μm or more, 1.3 μm or more, or 1.5 μm or more. The upper limit of D10 is not particularly limited, but may be 2.5 μm or less, 2.0 μm or less, or 1.8 μm or less. That is, D10 is preferably 0.30 to 2.5 μm, and the preferred upper and lower limits are as described above. It was also found that when D10 is equal to or greater than the predetermined value, the adhesive strength with the copper foil also tends to improve. The reason for this effect is speculated as follows: Comparing the resin component and the inorganic filler, the resin component has higher adhesion to the copper foil, while the adhesion between the inorganic filler and the copper foil is lower. In other words, it can be considered that the contact between the inorganic filler and the copper foil reduces adhesion. In this case, it is thought that as the D10 of the inorganic filler increases, the inorganic filler will have a small specific surface area, which reduces the contact area between the inorganic filler and the copper foil, thereby suppressing the decrease in adhesion. However, the validity of this speculation does not affect the scope of the present invention.

[0020] In addition, in component (B), when D90 is the particle diameter corresponding to the cumulative 90% by volume of the smallest particle diameter in the cumulative particle size distribution of the particles, it is preferable that D90 / D50 (the ratio of D90 to D50) be 1.80 or less. Having a D90 / D50 ratio of 1.80 or less reduces coarse particles, making it possible to suppress separation in the thermosetting resin composition during press molding in the production of laminates, and also tends to avoid reduced reliability and increased dielectric loss tangent (Df) in printed wiring boards due to separation in the resin composition. From the above viewpoints, D90 / D50 is preferably 1.70 or less, more preferably 1.60 or less, and even more preferably 1.58 or less. The lower limit of D90 / D50 is not particularly limited, but is 1.00 or more, and may be 1.20 or more, 1.30 or more, or 1.40 or more. In other words, D90 / D50 is preferably 1.00 to 1.80, and the preferred lower and upper limits are as described above. From the above viewpoints, D90 is preferably 7 μm or less, more preferably 6 μm or less, even more preferably 5 μm or less, particularly preferably 4.0 μm or less, most preferably 3.5 μm or less, and may be 2.0 μm or less, 1.5 μm or less, or 1.2 μm or less. The lower limit of D90 is not particularly limited, but may be 0.6 μm or more, 0.8 μm or more, or 0.90 μm or more. In other words, D90 is preferably 0.6 to 7 μm, and the preferred values ​​for the lower and upper limits are as described above.

[0021] In component (B), the D50 is preferably 0.50 to 5 μm. When D50 is 0.50 μm or more, the effect of component (B) in this embodiment, i.e., the effect of reducing the dielectric loss tangent (Df) while maintaining the properties of the other components, tends to be more fully exhibited, and the adhesive strength to the copper foil also tends to be improved. In other words, when D50 is 0.50 μm or more and D10 / D50 is within the above range, the effects of the present invention are more fully exhibited, and further, the adhesive strength to the copper foil also tends to be improved. Here, the reason for the improved adhesive strength to the copper foil is inferred to be the same as the reason why the adhesive strength to the copper foil tends to be improved when D10 is equal to or greater than the predetermined value. Furthermore, when D50 is 5 μm or less and D90 / D50 is 1.80 or less, coarse particles are reduced, which tends to suppress separation in the thermosetting resin composition during press molding in the production of a laminate, and also tends to avoid a decrease in reliability and an increase in dielectric loss tangent (Df) in printed wiring boards that are caused by separation in the resin composition. From these viewpoints, the D50 is more preferably from 0.50 to 4 μm, further preferably from 0.50 to 3.5 μm, particularly preferably from 0.55 to 3.0 μm, and most preferably from 0.60 to 2.5 μm.

[0022] There are no particular limitations on how D10, D50, and D90 of component (B) can be determined, but they can be determined by analyzing the cumulative particle size distribution of component (B) using a particle size distribution analyzer. The method and conditions for analyzing the cumulative particle size distribution may be, in detail, the same as those described in the Examples.

[0023] By including the component (B), the thermosetting resin composition of the present embodiment tends to have low thermal expansion, high elastic modulus, heat resistance, and flame retardancy in addition to the above-mentioned effects. The component (B) may be used alone or in combination of two or more. Examples of component (B) include silica, alumina, mica, beryllia, aluminum carbonate, magnesium hydroxide, aluminum hydroxide, aluminum silicate, calcium carbonate, calcium silicate, magnesium silicate, silicon nitride, boron nitride, clays such as calcined clay, talc, aluminum borate, and silicon carbide. Among these, from the viewpoints of low thermal expansion, elastic modulus, heat resistance, and flame retardancy, silica, alumina, mica, and talc are preferred, silica and alumina are more preferred, and silica is even more preferred. Examples of silica include crushed silica, fumed silica, and fused silica. Among these, fused silica is preferred, and fused spherical silica is more preferred. The shape of component (B) is not particularly limited, and it may be irregular, but spherical is preferred from the viewpoint of significantly achieving the effects of the present invention. A spherical shape reduces the specific surface area, which leads to (1) a smaller "interface" between the inorganic filler and the resin component, and (2) a reduced amount of surface treatment agent (coupling agent) on the surface of the inorganic filler, which tends to result in a lower dielectric loss tangent (Df). Furthermore, the contact area between the inorganic filler and the copper foil tends to be smaller, which tends to more easily suppress a decrease in adhesion.

[0024] The method for producing the component (B) used in this embodiment is not particularly limited, but examples include a method in which a crushed inorganic filler is put into a melting furnace to form spherical particles, and then the spherical particles are classified, and a method using a sol-gel process.

[0025] ((B) Component Content) In the thermosetting resin composition of the present embodiment, the content of the component (B) is not particularly limited, but in any case, from the viewpoints of the thermal expansion coefficient, elastic modulus, heat resistance, and flame retardancy, the content is preferably 5 to 95 mass %, more preferably 10 to 80 mass %, even more preferably 10 to 55 mass %, even more preferably 15 to 55 mass %, particularly preferably 25 to 55 mass %, and most preferably 30 to 50 mass %, relative to the total solid content in the thermosetting resin composition.

[0026] In addition, a coupling agent may be used in combination with the (B) component, if necessary, for the purpose of improving the dispersibility of the (B) component and the adhesion between the (B) component and the resin components in the thermosetting resin composition. Examples of the coupling agent include a silane coupling agent and a titanate coupling agent. One type of coupling agent may be used alone, or two or more types may be used in combination. As the coupling agent, a silane coupling agent is preferred. Examples of silane coupling agents include epoxysilane coupling agents, aminosilane coupling agents, vinylsilane coupling agents, phenylsilane coupling agents, alkylsilane coupling agents, alkenylsilane coupling agents, alkynylsilane coupling agents, haloalkylsilane coupling agents, siloxane coupling agents, hydrosilane coupling agents, silazane coupling agents, alkoxysilane coupling agents, chlorosilane coupling agents, (meth)acrylicsilane coupling agents, isocyanuratesilane coupling agents, ureidosilane coupling agents, mercaptosilane coupling agents, sulfidesilane coupling agents, isocyanatesilane coupling agents, etc. Among these, the use of a vinylsilane coupling agent tends to make it easier for the effects of the present invention to be realized. When a coupling agent is used, the treatment method may be a so-called integral blend treatment method in which an inorganic filler is blended into a thermosetting resin composition and then the coupling agent is added, but a method in which an inorganic filler is previously surface-treated with a coupling agent by a dry or wet method is used is preferred. By adopting this method, low thermal expansion, high elastic modulus, heat resistance, and flame retardancy can be more effectively achieved. If necessary, the component (B) may be used in the form of a slurry in which it has been dispersed in an organic solvent in advance.

[0027] The thermosetting resin composition of this embodiment may further contain other components. The other components are not particularly limited, but preferably contain one or more selected from the group consisting of (C) elastomer, (D) modified conjugated diene polymer, (E) curing accelerator, flame retardant, flame retardant aid, antioxidant, adhesion improver, heat stabilizer, antistatic agent, UV absorber, pigment, colorant, and lubricant, and more preferably contain one or more selected from the group consisting of (C) elastomer, (D) modified conjugated diene polymer, and (E) curing accelerator.

[0028] ((C) Elastomer) The thermosetting resin composition of the present embodiment is not particularly limited, but preferably contains (C) an elastomer (hereinafter, also referred to as component (C)). Examples of the (C) elastomer include styrene-based elastomers, olefin-based elastomers, urethane-based elastomers, polyester-based elastomers, polyamide-based elastomers, acrylic-based elastomers, silicone-based elastomers, etc. These elastomers are composed of hard segment components and soft segment components, and generally, the hard segment components contribute to heat resistance and strength, while the soft segment components contribute to flexibility and toughness. The component (C) may be used alone or in combination of two or more types.

[0029] From the viewpoint of dielectric loss tangent (Df), the styrene-based elastomer is preferred as component (C), and a styrene-based thermoplastic elastomer is more preferred. The styrene-based elastomer may have a structural unit derived from a styrene-based compound. From the viewpoints of dielectric loss tangent (Df), adhesion to a conductor, heat resistance, and low thermal expansion, one or more selected from the group consisting of hydrogenated styrene-butadiene-styrene block copolymers (SEBS, SBBS), hydrogenated styrene-isoprene-styrene block copolymers (SEPS), and styrene-maleic anhydride copolymers (SMA) are preferred, one or more selected from the group consisting of hydrogenated styrene-butadiene-styrene block copolymers (SEBS) and hydrogenated styrene-isoprene-styrene block copolymers (SEPS) are more preferred, and hydrogenated styrene-butadiene-styrene block copolymers (SEBS) are even more preferred. The styrene-based elastomer (excluding the SMA) may be modified with an acid anhydride such as maleic anhydride, and examples thereof include SEBS modified with an acid anhydride such as maleic anhydride, and SEPS modified with an acid anhydride such as maleic anhydride. The acid value of the acid-modified styrene-based elastomer (excluding the SMA) is not particularly limited, but is preferably 2 to 20 mg CHONa / g, more preferably 5 to 15 mg CHONa / g, and even more preferably 7 to 13 mg CHONa / g.

[0030] In component (C), the content of structural units derived from styrene (hereinafter sometimes referred to as "styrene content") is not particularly limited, but from the viewpoints of dielectric loss tangent (Df), adhesion to a conductor, heat resistance, and low thermal expansion, it is preferably 5 to 80 mass%, more preferably 10 to 75 mass%, even more preferably 15 to 60 mass%, and particularly preferably 20 to 45 mass%. The weight-average molecular weight (Mw) of component (C) is not particularly limited, but is preferably 12,000 to 1,000,000, more preferably 30,000 to 500,000, and may be 50,000 to 120,000, or even 70,000 to 100,000. In this specification, the weight-average molecular weight (Mw) is a value measured in terms of polystyrene by gel permeation chromatography (GPC), and more specifically, a value measured by the method described in the Examples. The melt flow rate (MFR) of component (C) is not particularly limited, but is preferably 0.1 to 20 g / 10 min, more preferably 0.5 to 15 g / 10 min, and may be 0.5 to 3 g / 10 min, 2 to 10 g / 10 min, or 3 to 7 g / 10 min, measured under conditions of 230°C and a load of 2.16 kgf (21.2 N).

[0031] ((C) Elastomer Content) When the thermosetting resin composition of this embodiment contains the elastomer (C), its content is not particularly limited, but is preferably 1 to 35 mass %, more preferably 3 to 30 mass %, even more preferably 5 to 25 mass %, and particularly preferably 10 to 25 mass %, of the total solid content in the thermosetting resin composition. When the content of the component (C) is equal to or greater than the lower limit, a better dielectric loss tangent (Df) tends to be obtained, and when it is equal to or less than the upper limit, good heat resistance, moldability, processability, and flame retardancy tend to be obtained.

[0032] ((D) Modified Conjugated Diene Polymer) The thermosetting resin composition of the present embodiment is not particularly limited, but preferably contains (D) a modified conjugated diene polymer (hereinafter, sometimes referred to as component (D)). The component (D) is preferably obtained by modifying (d1) a conjugated diene polymer having a vinyl group in the side chain [hereinafter, sometimes referred to as component (d1)] with (d2) a maleimide compound having two or more N-substituted maleimide groups [hereinafter, sometimes referred to as component (d2)]. The component (D) may be used alone or in combination of two or more types. The components (d1) and (d2) will be described in detail below.

[0033] ((d1) Conjugated diene polymer having vinyl groups in the side chains) The component (d1) is not particularly limited as long as it is a conjugated diene polymer having a vinyl group in the side chain, but is preferably a conjugated diene polymer having a plurality of vinyl groups in the side chain. The number of vinyl groups contained in one molecule of the component (d1) is preferably 3 or more, more preferably 5 or more, and even more preferably 10 or more, from the viewpoint of dielectric properties and heat resistance. The component (d1) may be used alone or in combination of two or more.

[0034] In this specification, the term "conjugated diene polymer" refers to a polymer of a conjugated diene compound, such as 1,3-butadiene, isoprene, 1,3-pentadiene, 2,3-dimethyl-1,3-butadiene, 2-phenyl-1,3-butadiene, or 1,3-hexadiene. The conjugated diene polymer may be a polymer of one kind of conjugated diene compound, or may be a polymer of two or more kinds of conjugated diene compounds. The conjugated diene polymer may be a copolymer of one or more conjugated diene compounds and one or more monomers other than the conjugated diene compounds. In this case, the polymerization method is not particularly limited and may be any of random polymerization, block polymerization, and graft polymerization.

[0035] Specific examples of component (d1) include polybutadiene having 1,2-vinyl groups, butadiene-styrene copolymer having 1,2-vinyl groups, and polyisoprene having 1,2-vinyl groups. Among these, from the viewpoint of dielectric properties and heat resistance, polybutadiene having 1,2-vinyl groups and butadiene-styrene copolymer having 1,2-vinyl groups are preferred, and polybutadiene having 1,2-vinyl groups is more preferred. Furthermore, as polybutadiene having 1,2-vinyl groups, butadiene homopolymer having 1,2-vinyl groups is preferred. The butadiene-derived 1,2-vinyl group contained in the component (d1) is a vinyl group contained in a butadiene-derived structural unit represented by the following formula (d1-1).

[0036] [ka]

[0037] When component (d1) is a polybutadiene having a 1,2-vinyl group, the content of structural units having a 1,2-vinyl group (structural units represented by the above general formula (d1-1)) relative to all structural units derived from butadiene constituting the polybutadiene [hereinafter sometimes abbreviated as vinyl group content] is preferably 50 mol% or more, more preferably 60 mol% or more, even more preferably 70 mol% or more, particularly preferably 80 mol% or more, and most preferably 84 mol% or more, from the viewpoints of compatibility with other resins, dielectric properties, low thermal expansion, and heat resistance. There is no particular upper limit to the vinyl group content, and it may be 100 mol% or less. From the same viewpoint, the polybutadiene having a 1,2-vinyl group is preferably a 1,2-polybutadiene homopolymer.

[0038] The number average molecular weight (Mn) of the (d1) component is preferably 400 to 4,000, more preferably 500 to 3,500, from the viewpoints of compatibility with other resins, dielectric properties, low thermal expansion, and heat resistance, and may be 2,000 to 3,500, 600 to 2,000, or 700 to 1,500.

[0039] ((d2) Maleimide Compound Having an N-Substituted Maleimide Group) The component (d2) may be a maleimide compound having one N-substituted maleimide group or two or more N-substituted maleimide groups. Of the maleimide compounds exemplified for the thermosetting resin (A), the component (d2) is preferably a maleimide compound having two or more N-substituted maleimide groups. The component (d2) may be used alone or in combination of two or more.

[0040] Among these, component (d2) is preferably at least one selected from the group consisting of aromatic bismaleimide compounds having preferably two N-substituted maleimide groups bonded to an aromatic ring and aromatic polymaleimide compounds having preferably three or more N-substituted maleimide groups bonded to an aromatic ring, as described in the description of the maleimide compound in component (A) above, from the viewpoints of solubility in organic solvents, suppression of gelation during the reaction, and compatibility with other resins in the resulting component (D), dielectric properties, low thermal expansion, and heat resistance, and is more preferably an aromatic bismaleimide compound having preferably two N-substituted maleimide groups bonded to an aromatic ring. In particular, component (d2) is more preferably a compound represented by the following general formula (d2-1), from the same viewpoints as above.

[0041] [ka] (In the formula, R d1 and R d2 are each independently an aliphatic hydrocarbon group having 1 to 5 carbon atoms. d1 represents an alkylene group having 1 to 5 carbon atoms, an alkylidene group having 2 to 5 carbon atoms, an ether group, a sulfide group, a sulfonyl group, a carbonyloxy group, a keto group, a single bond, or a divalent group represented by the following general formula (d2-1-1): q1 and q2 each independently represent an integer of 0 to 4.

[0042] R d1 and R d2 Examples of the aliphatic hydrocarbon group having 1 to 5 carbon atoms represented by include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a t-butyl group, an n-pentyl group, etc. From the viewpoints of compatibility with other resins and suppression of gelation during the reaction, the aliphatic hydrocarbon group is preferably an aliphatic hydrocarbon group having 1 to 3 carbon atoms, more preferably an alkyl group having 1 to 3 carbon atoms, and even more preferably an ethyl group or a methyl group.

[0043] X d1 Examples of the alkylene group having 1 to 5 carbon atoms represented by include a methylene group, a 1,2-dimethylene group, a 1,3-trimethylene group, a 1,4-tetramethylene group, a 1,5-pentamethylene group, etc. As the alkylene group, an alkylene group having 1 to 3 carbon atoms is preferred, and a methylene group is more preferred. X d1 Examples of the alkylidene group having 2 to 5 carbon atoms represented by include an ethylidene group, a propylidene group, an isopropylidene group, a butylidene group, an isobutylidene group, a pentylidene group, and an isopentylidene group. q1 and q2 each independently represent an integer of 0 to 4. From the viewpoints of availability, compatibility with other resins, and suppression of gelation during the reaction, each is preferably an integer of 0 to 2, and may be 0. From the viewpoints of compatibility with other resins and suppression of gelation during the reaction, it is preferable that q1+q2 is an integer of 1 or more, and it is more preferable that q1 and q2 are each 1 or 2, and it is even more preferable that each is 2. When q1 or q2 is an integer of 2 or more, a plurality of R d1 Comrades or R d2 They may be the same or different from each other. In addition, X d1 The divalent group represented by general formula (d2-1-1) is as follows:

[0044] [ka] (In the formula, R d3 and Rd4 are each independently an aliphatic hydrocarbon group having 1 to 5 carbon atoms or a halogen atom. d2 represents an alkylene group having 1 to 5 carbon atoms, an alkylidene group having 2 to 5 carbon atoms, an ether group, a sulfide group, a sulfonyl group, a carbonyloxy group, a keto group, or a single bond. q3 and q4 each independently represent an integer of 0 to 4. * represents a bonding site.

[0045] R d3 and R d4 The aliphatic hydrocarbon group having 1 to 5 carbon atoms represented by R d1 This is explained in the same way as in the case of X d2 The alkylene group having 1 to 5 carbon atoms and the alkylidene group having 2 to 5 carbon atoms represented by X d1 Examples of the alkylene group having 1 to 5 carbon atoms and the alkylidene group having 2 to 5 carbon atoms are the same as those represented by the formula (I). q3 and q4 are each independently an integer of 0 to 4, and from the viewpoint of availability, may be either an integer of 0 to 2, or may be 0 or 1, or may be 0. When q3 or q4 is an integer of 2 or more, a plurality of R d3 Comrades or R d4 They may be the same or different from each other.

[0046] Examples of the compound represented by general formula (d2-1) include 4,4'-diphenylmethane bismaleimide, 2,2-bis[4-(4-maleimidophenoxy)phenyl]propane, 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethane bismaleimide, etc. Among these, 4,4'-diphenylmethane bismaleimide is preferred from the viewpoints of solubility in organic solvents and suppression of gelation during the reaction, as well as compatibility with other resins of the obtained component (D), dielectric properties, low thermal expansion, and heat resistance. As the component (d2), in addition to the compound represented by the general formula (d2-1), 4-methyl-1,3-phenylenebismaleimide and the like are also preferably used.

[0047] (Reaction conditions) The method for reacting component (d1) and component (d2) is not particularly limited, and for example, component (D) can be obtained by charging predetermined amounts of components (d1), (d2), a reaction catalyst, and an organic solvent into a reaction vessel and, if necessary, reacting them while heating, keeping the temperature, stirring, etc. The reaction conditions in this step can be adjusted appropriately depending on the types of raw materials used, etc., but from the viewpoints of workability and suppressing gelation during the reaction, the reaction temperature is preferably 70 to 120°C, and the reaction time is preferably 0.5 to 15 hours.

[0048] As the reaction catalyst, a curing accelerator (E) described below can be used. Among these, organic peroxides are preferred, and α,α'-bis(t-butylperoxy)diisopropylbenzene is more preferred, from the viewpoint of obtaining sufficient reactivity while suppressing gelation during the reaction. The reaction catalyst may be used alone or in combination of two or more kinds.

[0049] When carrying out the above reaction, the blending amounts of the (d1) and (d2) components are determined based on the mole number (M v ) 、 The number of moles of N-substituted maleimide groups in the component (d2) (M m ) ratio (M m / M v ) is preferably 0.01 to 0.5, more preferably 0.02 to 0.4, and even more preferably 0.04 to 0.3.

[0050] By the above reaction, at least a portion of the vinyl groups in the side chain of component (d1) react with the N-substituted maleimide groups in component (d2), producing component (D). The resulting component (D) has a substituent (x) in the side chain formed by the reaction of the vinyl groups in component (d1) with the N-substituted maleimide groups in component (d2). Component (D) preferably has a substituent (x) and a vinyl group (y) in the side chain, and the vinyl group (y) is preferably a 1,2-vinyl group contained in a structural unit derived from butadiene. The extent to which the substituent (x) is present in component (D) can be determined by the extent to which the vinyl groups in component (d1) have been modified by component (d2) (hereinafter referred to as the "vinyl group modification rate"). From the viewpoints of compatibility with other resins, dielectric properties, low thermal expansion, and heat resistance, the vinyl group modification rate is preferably 1% or more, i.e., 1 to 100%, more preferably 1 to 95%, even more preferably 5 to 85%, still more preferably 10 to 80%, particularly preferably 25 to 80%, and most preferably 35 to 75%. Here, the modification rate of vinyl groups is a value determined by the method described in the examples.

[0051] The number average molecular weight (Mn) of component (D) is not particularly limited, but from the viewpoints of compatibility with other resins, dielectric properties, low thermal expansion, and heat resistance, it is preferably 700 to 6,000, more preferably 800 to 5,000, even more preferably 900 to 4,500, and particularly preferably 1,000 to 4,000.

[0052] ((D) Content of modified conjugated diene polymer) When the thermosetting resin composition of the present embodiment contains the component (D), its content is not particularly limited, but from the viewpoints of compatibility with other resin components, dielectric loss tangent (Df), low thermal expansion, and heat resistance, it is preferably 1 to 40 mass%, more preferably 3 to 30 mass%, even more preferably 5 to 25 mass%, and particularly preferably 7 to 20 mass%, relative to the total solid content in the thermosetting resin composition.

[0053] ((E) Curing accelerator) Examples of the (E) curing accelerator (hereinafter sometimes referred to as component (E)) include amine-based curing accelerators, imidazole-based curing accelerators, phosphorus-based curing accelerators, organometallic salts, acidic catalysts, and organic peroxides. In this embodiment, imidazole-based curing accelerators are not classified as amine-based curing accelerators. One type of curing accelerator may be used alone, or two or more types may be used in combination. Organic peroxides are preferred as the curing accelerator. Examples of the organic peroxides include dicumyl peroxide, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexyne-3, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexane, t-butylperoxyisopropyl monocarbonate, and α,α'-bis(t-butylperoxy)diisopropylbenzene.

[0054] ((E) Content of hardening accelerator) When the thermosetting resin composition of this embodiment contains component (E), its content is not particularly limited, but in any case, it is preferably 0.01 to 3 mass%, more preferably 0.05 to 2.5 mass%, still more preferably 0.1 to 2.0 mass%, and particularly preferably 0.3 to 1.5 mass%, relative to the total amount of resin components in the thermosetting resin composition. When the content of (E) curing accelerator is within the above range, better heat resistance, storage stability, and moldability tend to be obtained.

[0055] (Content of ingredients other than the above ingredients) When the thermosetting resin composition of the present embodiment contains components other than the above components (flame retardants, flame retardant aids, antioxidants, adhesion improvers, heat stabilizers, antistatic agents, ultraviolet absorbers, pigments, colorants, lubricants, and other components), the content of each of these components is not particularly limited, and may be, for example, 0.01 parts by mass or more, 10 parts by mass or less, 5 parts by mass or less, 1 part by mass or less, or none at all, relative to 100 parts by mass of the total resin components of the thermosetting resin composition.

[0056] (organic solvent) The thermosetting resin composition of the present embodiment may be a so-called "varnish" containing an organic solvent, from the viewpoint of facilitating handling and facilitating production of a prepreg, which will be described later. The organic solvent is not particularly limited, but examples thereof include alcohol-based solvents such as ethanol, propanol, butanol, methyl cellosolve, butyl cellosolve, and propylene glycol monomethyl ether; ketone-based solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ether-based solvents such as tetrahydrofuran; aromatic solvents such as toluene, xylene, and mesitylene; nitrogen-containing solvents such as dimethylformamide, dimethylacetamide, and N-methylpyrrolidone; sulfur-containing solvents such as dimethyl sulfoxide; and ester-based solvents such as γ-butyrolactone. From the viewpoint of solubility, ketone-based solvents are preferred, and methyl ethyl ketone is more preferred. The organic solvents may be used alone or in combination of two or more.

[0057] When the thermosetting resin composition of this embodiment is used as a varnish, the solids concentration is preferably 30 to 90 mass%, more preferably 40 to 80 mass%, and even more preferably 45 to 60 mass%. When the solids concentration of the thermosetting resin composition is within this range, the thermosetting resin composition is easy to handle, the impregnation into a substrate and the appearance of the produced prepreg are good, and the coatability when forming a resin film is also good.

[0058] The thermosetting resin composition of this embodiment can be produced by mixing component (A) and component (B) and the other optional components by a known method. In this process, each component may be dissolved or dispersed in the organic solvent while stirring. The mixing order, temperature, time, and other conditions are not particularly limited and can be set as desired.

[0059] [Prepreg] The prepreg of the present embodiment is a prepreg containing the thermosetting resin composition of the present embodiment or a semi-cured product of the thermosetting resin composition. The prepreg of this embodiment contains, for example, the thermosetting resin composition of this embodiment or a semi-cured product of the thermosetting resin composition and a sheet-like fiber substrate. The prepreg is formed using the thermosetting resin composition of this embodiment and a sheet-like fiber substrate. For example, the prepreg can be obtained by impregnating or coating the sheet-like fiber substrate with the thermosetting resin composition of this embodiment, and then heating and drying the composition to semi-cure (B-stage) as necessary. More specifically, the prepreg of this embodiment can be produced by heating and drying the composition in a drying oven, typically at 80 to 200°C for 1 to 30 minutes to semi-cure (B-stage). Here, B-staging as used herein refers to achieving the B-stage state defined by JIS K6900 (1994). The amount of the thermosetting resin composition used can be appropriately determined so that the solid content concentration derived from the thermosetting resin composition in the dried prepreg is 30 to 90 mass %. By setting the solid content concentration within this range, better moldability tends to be obtained when the laminate is made.

[0060] As the sheet-like fiber substrate for the prepreg, known materials used in various laminates for electrical insulating materials are used. Materials for the sheet-like fiber substrate include inorganic fibers such as E-glass, D-glass, S-glass, and Q-glass; organic fibers such as polyimide, polyester, and tetrafluoroethylene; and mixtures thereof. These sheet-like fiber substrates have shapes such as woven fabric, nonwoven fabric, roving, chopped strand mat, and surfacing mat.

[0061] [Resin film] The resin film of the present embodiment is a resin film containing the thermosetting resin composition of the present embodiment or a semi-cured product of the thermosetting resin composition. The resin film of this embodiment can be produced, for example, by applying a thermosetting resin composition containing an organic solvent, i.e., a varnish, to a support, heating and drying it, and semi-curing (B-staging) it as needed. Examples of the support include a plastic film, a metal foil, and a release paper. The drying temperature and drying time may be determined appropriately depending on the amount of organic solvent used, the boiling point of the organic solvent used, etc., but a resin film can be suitably formed by drying at 50 to 200°C for about 1 to 10 minutes.

[0062] [Laminate] The laminate of this embodiment is a laminate having a cured product of the thermosetting resin composition of this embodiment or a cured product of the prepreg, and a metal foil. The laminate of this embodiment can be produced, for example, by placing metal foil on one or both sides of a single prepreg of this embodiment, or by placing metal foil on one or both sides of a laminate obtained by stacking two or more prepregs of this embodiment, and then hot-pressing and molding. In the laminate produced by this production method, the prepreg of this embodiment is C-staged. In this specification, C-stage refers to achieving the C-stage state defined in JIS K6900 (1994). A laminate having metal foil is also sometimes called a metal-clad laminate. The metal of the metal foil is not particularly limited, but from the viewpoint of electrical conductivity, it may be copper, gold, silver, nickel, platinum, molybdenum, ruthenium, aluminum, tungsten, iron, titanium, chromium, or an alloy containing one or more of these metal elements, with copper and aluminum being preferred, and copper being more preferred. The conditions for hot pressing are not particularly limited, but may be, for example, a temperature of 100 to 300°C, a pressure of 0.2 to 10 MPa, and a time of 0.1 to 5 hours. Alternatively, hot pressing may be performed using a vacuum press or the like to maintain a vacuum state for 0.5 to 5 hours.

[0063] [Printed wiring board] The printed wiring board of this embodiment comprises one or more selected from the group consisting of a cured product of the thermosetting resin composition of this embodiment, a cured product of the prepreg of this embodiment, and a laminate of this embodiment. The printed wiring board of this embodiment can be manufactured by performing circuit formation processing such as drilling, metal plating, and metal foil etching using a known method, using one or more selected from the group consisting of the prepreg of this embodiment, the resin film of this embodiment, and the laminate of this embodiment. A multilayer printed wiring board can be manufactured by further performing multilayer adhesion processing as needed. In the printed wiring board of this embodiment, the prepreg of this embodiment and the resin film of this embodiment are C-staged.

[0064] [Semiconductor Package] The semiconductor package of this embodiment is a semiconductor package having the printed wiring board of this embodiment and a semiconductor element. The semiconductor package of this embodiment can be manufactured by mounting semiconductor elements such as semiconductor chips and memories at predetermined positions on the printed wiring board of this embodiment.

[0065] The resin composition, prepreg, resin film, laminate, printed wiring board, and semiconductor package of this embodiment can be suitably used in electronic devices that handle high-frequency signals of 10 GHz or higher. In particular, the printed wiring board is useful as a printed wiring board for millimeter-wave radar.

[0066] Although preferred embodiments have been described above, these are merely examples for the purpose of explaining the present disclosure, and the scope of the present disclosure is not intended to be limited to these embodiments. The present disclosure also includes various aspects that differ from the above-described embodiments without departing from the gist of the present disclosure. [Example]

[0067] The present embodiment will be specifically described below with reference to examples, but the present embodiment is not limited to the following examples.

[0068] In each example, the number average molecular weight (Mn) and weight average molecular weight (Mw) were measured by the following methods. (1. Method for measuring number average molecular weight (Mn) and weight average molecular weight (Mw)) The values ​​were calculated by gel permeation chromatography (GPC) from a calibration curve using standard polystyrene. The calibration curve was approximated by a cubic equation using standard polystyrene: TSKstandard POLYSTYRENE (Types: A-2500, A-5000, F-1, F-2, F-4, F-10, F-20, F-40) [manufactured by Tosoh Corporation, trade name]. The GPC measurement conditions are shown below. Device: Pump: L-6200 type [manufactured by Hitachi High-Technologies Corporation] Detector: L-3300 type RI [Hitachi High-Technologies Corporation] Column oven: L-655A-52 [Hitachi High-Technologies Corporation] Column: Guard column: TSK Guardcolumn HHR-L + column: TSKgel G4000HHR + TSKgel G2000HHR (all manufactured by Tosoh Corporation, product names) Column size: 6.0 x 40 mm (guard column), 7.8 x 300 mm (column) Eluent: tetrahydrofuran Sample concentration: 30 mg / 5 mL Injection volume: 20μL Flow rate: 1.00mL / min Measurement temperature: 40℃

[0069] Furthermore, for the components (B) and (B') used in each example, D10, D50 and D90 were measured by the following methods. (2. Measurement method of D10, D50 and D90 / particle size distribution) The cumulative particle size distribution was measured using a particle size distribution measuring device "Microtrac MT3000" (manufactured by Microtrac Bell Co., Ltd.). The operating procedure is as follows. First, an operation of circulating methyl isobutyl ketone in the apparatus and then discharging it was repeated three times, and then methyl isobutyl ketone was introduced again to replace the inside of the apparatus with methyl isobutyl ketone. A slurry of spherical silica (solid content concentration 60 to 70% by mass, dispersion solvent: methyl isobutyl ketone) was added to methyl isobutyl ketone so as to achieve a scattering intensity within a predetermined range, and then the cumulative particle size distribution was measured using the obtained dispersion with the above-mentioned device. The measurement parameters were as follows: refractive index input mode was set to transmission, spherical to aspherical, particle refractive index was set to 1.45, and dispersion medium refractive index was set to 1.40. From the obtained cumulative particle size distribution, the values ​​of D10, D50 and D90 were obtained.

[0070] (3. Measurement of the rate of modification of vinyl groups) The value determined by the following method was taken as the modification rate of the vinyl group of the modified conjugated diene polymer. The liquid containing the (d1) and (d2) components before the start of the reaction and the liquid containing the (D) modified conjugated diene polymer obtained after the reaction were subjected to GPC measurement in the same manner as described above. The reduction rate of the peak area derived from the (d2) component before and after the reaction, i.e., (peak area derived from the (d2) component before the reaction - peak area derived from the (d2) component after the reaction) × 100 / (peak area derived from the (d2) component before the reaction), was determined, and the resulting value was taken as the modification rate of the vinyl group.

[0071] Manufacturing Example 1 (D) Preparation of Modified Conjugated Diene Polymers The components (d1) and (d2), an organic peroxide, and toluene as an organic solvent in the amounts shown in Table 1 were placed in a 2 L glass flask equipped with a thermometer, a reflux condenser, and a stirrer, and the mixture was allowed to react under stirring at 90 to 100°C for 5 hours in a nitrogen atmosphere to obtain a liquid containing modified conjugated diene polymer D-1 (toluene diluted solution, solids concentration: 35% by mass). Table 1 shows the vinyl group modification rate and number average molecular weight of the resulting modified conjugated diene polymer D-1. [Table 1]

[0072] The details of each component listed in Table 1 are as follows: [(d1) component] Polybutadiene 1:1,2-polybutadiene homopolymer, number average molecular weight = 1,200, vinyl group content = 85% or more [(d2) component] Bismaleimide Compound 1: 4,4'-Diphenylmethane Bismaleimide [Reaction catalyst] Organic peroxide: α,α'-bis(t-butylperoxy)diisopropylbenzene

[0073] [Examples 1 to 3, Comparative Example 1] The components shown in Table 2 were mixed with methyl ethyl ketone at room temperature under stirring according to the formulation shown in Table 2 to prepare a thermosetting resin composition (varnish) with a solid content of 55 mass %. The varnish obtained above was applied to a 0.08 mm thick glass cloth (NE Glass, manufactured by Nitto Boseki Co., Ltd.) and then heated and dried at 105°C for 4 minutes to produce a prepreg with a solids content of approximately 75% by mass derived from the thermosetting resin composition. 18 μm thick low-profile copper foil (SI-VSP18, manufactured by Mitsui Mining & Smelting Co., Ltd.; "VSP" is a registered trademark) was placed on top and bottom of this prepreg with the matte side (M side) in contact with the prepreg, and then hot-pressed at 190°C, 3.0 MPa, and for 80 minutes to produce a double-sided copper-clad laminate (thickness: 0.60 mm). The double-sided copper-clad laminates obtained in each example were evaluated according to the following methods. The results are shown in Table 2.

[0074] [Evaluation of double-sided copper-clad laminates] (4. Dielectric loss tangent (Df)) The outer copper foil of each double-sided copper-clad laminate was removed by immersion in a copper etching solution (10% by weight ammonium persulfate solution, manufactured by Mitsubishi Gas Chemical Company, Inc.). A 60 mm long, 2 mm wide specimen was cut out and used to measure the dielectric loss tangent (Df) using the cavity resonator perturbation method. The measuring instrument used was an Agilent Technologies N5222B vector network analyzer, the Kanto Electronics Application Development Co., Ltd. CP129 (10 GHz band resonator) cavity resonator, and the measurement program was CPMA-V2. The measurements were performed at a frequency of 10 GHz and a temperature of 25°C.

[0075] (5. Adhesion strength with copper foil) The adhesive strength to the copper foil was measured using Shimadzu Corporation's "EZ-Test / CE" according to the following method. The copper foil of the double-sided copper-clad laminate obtained in each example was etched into a 3 mm wide straight line and then dried at 105°C / hr to prepare a test piece. Using this test piece, the copper foil was peeled off in a 90° direction in accordance with JIS C6481 to measure the peel strength. The pulling speed was 50 mm / min.

[0076] [Table 2]

[0077] Each component listed in Table 2 is explained below. [(A) Thermosetting resin] Maleimide compound A-1: ​​Indan ring-containing aromatic bismaleimide (number average molecular weight 1,200) Maleimide Compound A-2: 4,4'-Diphenylmethanebismaleimide

[0078] [(B) Inorganic filler with D10 / D50 of 0.70 or more, and (B') inorganic filler] The inorganic fillers used were spherical silica B-1 to B-3 or B'-4, each surface-treated with a vinylsilane coupling agent, and each of the spherical silica B-1 to B-3 and B'-4 had a particle size as shown in Table 3 below. [Table 3]

[0079] [(C) Elastomer] Thermoplastic elastomer C-1: styrene-ethylene-butylene-styrene copolymer (SEBS), styrene content 42% by mass, weight average molecular weight (Mw) = 75,000 Thermoplastic elastomer C-2: Styrene-ethylene-butylene-styrene copolymer (SEBS), styrene content 30 mass, weight average molecular weight (Mw) = 86,000

[0080] [(D) Modified conjugated diene polymer] Modified conjugated diene polymer D-1: Modified conjugated diene polymer D-1 obtained in Production Example 1

[0081] [(E) Curing accelerator] Organic peroxide E-1: Dicumyl peroxide

[0082] From the results in Table 1, Examples 1 to 3 have lower dielectric loss tangents (Df) than Comparative Example 1. Furthermore, Examples 1 to 3 also have excellent adhesive strength to the copper foil. On the other hand, in Comparative Example 1, although the D50 of the spherical silica B'-4 used was between the D50 of the spherical silica B-1 (Example 1) and the D50 of the spherical silica B-2 (Example 2), the dielectric loss tangent (Df) was high because the D10 / D50 was less than 0.70.

Claims

1. A thermosetting resin composition comprising (A) a thermosetting resin, (B) an inorganic filler, and (C) an elastomer, The thermosetting resin composition of the (B) inorganic filler, wherein D10 is a particle diameter corresponding to a cumulative 10% by volume from the smallest particle diameter in a cumulative particle size distribution of the particles, and D50 is a particle diameter corresponding to a cumulative 50% by volume from the smallest particle diameter, and the ratio D10 / D50 is 0.70 or more.

2. 2. The thermosetting resin composition according to claim 1, wherein, in the inorganic filler (B), when D90 is the particle diameter corresponding to cumulative 90% by volume from the smallest particle diameter in a cumulative particle size distribution of the particles, D90 / D50 is 1.80 or less.

3. 3. The thermosetting resin composition according to claim 1, wherein the inorganic filler (B) has a D50 of 0.50 to 5 μm.

4. The thermosetting resin composition according to any one of claims 1 to 3, wherein the content of the inorganic filler (B) is 5 to 95 mass% based on the total solid content in the thermosetting resin composition.

5. The thermosetting resin composition according to any one of claims 1 to 4, wherein the (A) thermosetting resin comprises at least one selected from the group consisting of an epoxy resin, a maleimide compound, a polyphenylene ether resin, a phenolic resin, a polyimide resin, a cyanate resin, an isocyanate resin, a benzoxazine resin, an oxetane resin, an amino resin, an unsaturated polyester resin, an allyl resin, a dicyclopentadiene resin, a silicone resin, a triazine resin, and a melamine resin.

6. A thermosetting resin composition described in any one of claims 1 to 5, wherein the content of (C) elastomer is 1 to 35 mass% relative to the total solid content in the thermosetting resin composition.

7. The thermosetting resin composition according to any one of claims 1 to 6, further comprising (D) a modified conjugated diene polymer.

8. The thermosetting resin composition according to any one of claims 1 to 7, further comprising (E) a curing accelerator.

9. A prepreg comprising the thermosetting resin composition according to any one of claims 1 to 8 or a semi-cured product of the thermosetting resin composition.

10. A resin film comprising the thermosetting resin composition according to any one of claims 1 to 8 or a semi-cured product of the thermosetting resin composition.

11. A laminate comprising a cured product of the thermosetting resin composition according to any one of claims 1 to 8 or a cured product of the prepreg according to claim 9 and a metal foil.

12. A printed wiring board having one or more selected from the group consisting of a cured product of the thermosetting resin composition according to any one of claims 1 to 8, a cured product of the prepreg according to claim 9, and the laminate according to claim 11.

13. A semiconductor package comprising the printed wiring board according to claim 12 and a semiconductor element.

Images