thermosetting resin sheets

Abstract

The objective of this invention is to provide thermosetting resin sheets, etc., that produce a curable material with a low dielectric loss tangent and an arithmetic mean roughness (Ra) that ensures elongation and adhesion to solder resist. The solution of this invention is a thermosetting resin sheet comprising a support and a resin composition layer disposed on the support; the resin composition layer comprises (A) a compound represented by formula (1), (B) an epoxy resin, and (C) an inorganic filler, wherein when the non-volatile component in the resin composition layer is set to 100% by mass, the content of component (C) is 40% by mass or more.