Abstract: A composition comprising (A) an epoxy resin having at least two epoxy groups in a molecule, (B) a silicone-modified epoxy resin, (C) an imidazole curing agent having a solubility of up to 0.1% by weight in epoxy resin (A) at 25.degree. C., and (D) fused silica having a mean particle size of up to 10 .mu.m and adjusted to a viscosity of up to about 4,000 poise at 25.degree. C. satisfies the requirements for flip chip encapsulation since the composition has improved shelf stability and filling ability and cures into products having improved moisture resistance. Semiconductor devices encapsulated with cured products of the composition remain reliable because of moisture resistance.

Abstract: A curable polyimide resin is blended with (a) an organic silicon compound having a functional group selected from an epoxy group and an amino group or (b) a copolymer of an aromatic polymer and an organic silicon compound. The resulting polyimide resin composition can be cured without inducing a crack. It is suitable for the encapsulation of semiconductor devices as well as for molding and powder coating.