Thermosetting resin composition, prepreg, resin-coated metal foil, laminate, printed wiring board, and semiconductor package

A thermosetting resin composition comprising (A) a phenol-based resin and (B) a thermosetting resin,

• the component (A) containing (A-1) a phenol-based resin having an aliphatic hydrocarbon group having 10 to 25 carbon atoms, having a weight average molecular weight (Mw) of 1,412 to 1,738, and having a hydroxy group equivalent of 214 to 238 g/eq, and (A-2) a phenol-based resin that does not have an aliphatic hydrocarbon group having 10 to 25 carbon atoms and having a hydroxy group equivalent of 80 to 150 g/eq, wherein:
• the component (A-1) has at least one kind of a structural unit selected from the group consisting of a structural unit (a1) represented by the following general formula (a1) and a structural unit (a2) represented by the following general formula (a2):
• wherein R1 represents a hydrogen atom, an aliphatic hydrocarbon group having 1 to 9 carbon atoms, which optionally have a substituent, an aromatic hydrocarbon group having 5 to 15 ring atoms, which optionally have a substituent, or a combination of the aliphatic hydrocarbon group and the aromatic hydrocarbon group;
• R2 represents an aliphatic hydrocarbon group having 10 to 25 carbon atoms;
• X represents a hydrogen atom, a hydroxy group, or a hydroxymethyl group;
• and m and n each independently represent 0 or 1;
• the component (A-2) comprises a cresol novolac phenol resin;
• the component (B) comprises at least one thermosetting resin selected from the group consisting of a dicyclopentadiene epoxy resin, a tetrabromobisphenol A epoxy resin, a naphthalene skeleton-containing novolac epoxy resin, a phenol novolac epoxy resin, and a phenol biphenyl aralkyl epoxy resin, wherein a content of the component (B) is 60 to 90 parts by mass per 100 parts by mass of the total resin content of the thermosetting resin composition;
• the thermosetting resin composition further comprises a curing accelerator (C) in an amount of 0.01 to 10 parts by mass per 100 parts by mass of the total resin content of the thermosetting resin composition, a filler (D) in an amount of 5 to 40 parts by mass per 100 parts by mass of the total resin content of the thermosetting resin composition, and a coupling agent in an amount of 0.01 to 20 parts by mass per 100 parts by mass of the total resin content of the thermosetting resin composition;
• and
• a content of the component (A-1) is from 10 to 18 parts by mass per 100 parts by mass of the total resin content of the thermosetting resin composition and a content ratio of the component (A-1) is from 30 to 95% by mass based on the total amount of the component (A-1) and the component (A-2).