“…In many cases a junction coat (layer of plastic such as an epoxy, silicone varnish, or room-temperature vulcanizing silicone elastomer) was applied prior to molding (84,97,121,311,165,2). Plastics can be a source of ions (182,128,230,228,29,166,177,308) or impurities (183,230,135,298,176) which adversely affect silicon devices, particularly in moist atmospheres and under bias conditions. In the last several years, a considerable number of process and materials changes has been made to improve the reliability of plastic-encapsulated silt,con integrated circuits (96,24,95,98,165,113).…”