Abstract: A flame retardant epoxy resin composition suitable for semiconductor encapsulation contains (A) a crystalline epoxy resin whose 30 wt % m-cresol solution has a viscosity of lower than 80 centipoise at 25° C., (B) a curing agent having at least two phenolic hydroxyl groups, and (C) silica. The composition optionally contains (D) an organopolysiloxane, (E) an organic phosphine oxide, (F) an amide group-containing release agent, and/or (G) a silane coupling agent. The cured composition achieves flame retardance rating UL-94 V-0 without a need for flame retardants and remains stable at high temperature.

Abstract: An epoxy resin composition contains (A) an epoxy resin having an epoxy equivalent of at least 185 and possessing a skeleton having a structure in which two benzene rings are conjugable to each other directly or via an aliphatic unsaturated double bond, carbon atoms having an atomic orbital of SP.sup.2 type accounting for at least 50% of the carbon number, (B) a phenolic resin having a hydroxyl equivalent of at least 160, carbon atoms having an atomic orbital of Sp.sup.2 type accounting for at least 85% of the carbon number, (C) a polyimide resin in an amount of 1-20 parts by weight per 100 parts by weight of components (A) and (B) combined, and (D) 70-85% by volume of the entire composition of an inorganic filler. The composition cures into products having flame retardancy and high-temperature reliability even though it is free of bromine compounds and antimony compounds.

Abstract: An epoxy resin composition comprising a crystalline epoxy resin, a phenolic resin, and an inorganic filler is improved in moldability by previously reacting phenolic hydroxyl groups on the phenolic resin with epoxy groups on the crystalline epoxy resin to form a reaction product and blending the reaction product in the composition. The composition is moldable over semiconductor devices without voids and wire flow. The encapsulated semiconductor devices thus remain reliable.

Abstract: Novel organic silicon compounds are based on a benzene ring having two epoxy radicals and an alkoxysilane radical. They are useful as resin modifiers, adhesive aids for epoxy resins, and silane coupling agents. Inorganic fillers such as silica surface treated with the compounds are useful in encapsulating resin compositions.