Abstract: Semiconductor devices which comprise a semiconductor chip, electrically conductive materials for connections to external leads, and encapsulated by a sealing resin has a surface and a portion of the electrically conductive material covered with a hardened silicone layer whose surface is exposed to ultraviolet radiation and the irradiation processed surface adheres to and is unified with the sealing resin. The sealing resin does not break easily when the device is exposed to heat cycles, thermal shock, repeated interruptions in current flow, and long periods of time at high temperature or low temperature. Such devices also exhibit excellent properties of moisture resistance, corrosion resistance and stress relaxation.

Abstract: Cured electrically conductive silicone rubber products exhibiting bleed-out of a silicone oil at a controlled rate are prepared from compositions containing carbon black and a curable polyorganosiloxane wherein 90 mol % of the silicon-bonded hydrocarbon groups are methyl. The silicone oil is a liquid polyorganosiloxane containing at least 1 mol %, based on the total number of hydrocarbon radicals present in said silicone oil, of silicon-bonded halogenated hydrocarbon radicals and the silicone oil is incompatible with the cured silicone rubber product.