Abstract: A plastic-sealed IC device comprises an IC lead frame having a chip mounting area, an IC chip fixedly mounted on the IC lead frame in the chip mounting frame area, and a plastic package molded so as to seal the IC lead frame therein.The plastic package has an opening formed so as to allow the backside of the chip mounting area to communicate with the atomonphere to discharge the moisture accumulating in the vicinity of the IC chip.

Abstract: A heat-resistant plastic-packaged semiconductor device comprises an IC chip having contacts on its first surface, an island on which the IC chip is mounted with its second surface facing a first surface of the island, a low-adhesion layer which is formed on a second surface of the island, external leads, bonding wires for connection of the contacts on the IC chip and inner ends of the external leads, a package of mold resin for encapsulating the IC chip, the low-adhesion layer, the bonding wires and inner parts of the external leads, the mold resin being provided with a vent hole which extends to the vicinity of the low-adhesion layer. The low-adhesion layer has a low or no adhesive power to the mold resin.