Heat-resistant plastic semiconductor device

Claim 1

A heat-resistant plastic-packaged semiconductor device capable of releasing a quantity of thermally expanded vapor resulting from penetration of water from a humid environment and a subsequent application of heat, comprising an integrated circuit chip having first and second surfaces, said chip having contacts on said first surface; an integrated circuit lead frame including external leads and an island on which the integrated circuit chip is mounted with said second surface facing a first surface of the island; a low-adhesion layer formed on a second surface of the island, said low-adhesion layer being formed of at least one element from the group consisting of Au, Ni, Cr, and Co; bonding wires for connecting the contacts on the integrated circuit chip and inner ends of the external leads; a package of epoxy resin for encapsulating the integrated circuit chip, the island, the low-adhesion layer, the bonding wires and inner ends of the external leads, said epoxy resin being provided with a vent hole which extends to the vicinity of said low-adhesion layer thereby exposing the surface of the low-adhesion layer to allow said thermally expanded vapor to be released from around the integrated circuit chip during subsequent heating, said low-adhesion layer adhering weakly to said epoxy resin.