Thermosetting resin compositions for filling holes, cured products, and electronic components

Abstract

A thermosetting resin composition for via filling, a cured product, and an electronic component are disclosed. The composition is particularly suitable for filling through-holes or vias in printed circuit boards. It has a suitable viscosity, and the cured product formed therefrom possesses a low dielectric constant, a low dielectric loss tangent, a suitable coefficient of thermal expansion, and good solder heat resistance. The thermosetting resin composition for via filling contains at least the following components (A) to (C): (A) a difunctional epoxy resin, (B) a trifunctional or higher epoxy resin, and (C) an inorganic filler, wherein the mass ratio of (A) a difunctional epoxy resin to (B) a trifunctional or higher epoxy resin is 1:4 to 2:1, the content of (C) the inorganic filler is 60% by mass or more, and the chlorine content in the thermosetting resin composition for via filling is 800 ppm or less.