| abstract |
A substrate, a circuit board and a multilayer circuit board are provided which, although being made of an inorganic filler as a crushed product, are capable of providing a highly reliable hybrid integrated circuit because of having excellent adhesion to a metal plate or metal foil and exhibiting a high thermal conductivity. n A resin composition comprising a curable resin comprising an epoxy resin and a curing agent for the epoxy resin; and an inorganic filler filled in the curable agent; wherein the curing agent comprises a phenol novolak resin, and wherein the inorganic filler comprises a coarse powder containing particles having an average particle size of 5 to 20 μm, preferably particles is having a maximum particle size of 100 μm or below and a particle size of 5 to 50 μm in an amount of 50 vol % or above; and a fine powder containing particles having an average particle size of 0.2 to 1.5 μm, preferably particles having a particle size of 2.0 μm or below in an amount of 70 vol % or above. A substrate for a hybrid integrated circuit, a circuit board and a multilayer circuit board, which use the resin composition. |