High-reliability plastic-packaged semiconductor device

Claim 1

A plastic-packaged semiconductor device having improved resistance to degradation in the presence of water vapor and corrosive atmospheres comprising a body of silicon having a surface, PN junction-defining regions in said body adjacent to said surface, passivating means comprising a layer of silicon dioxide on said surface and a silicon nitride layer on said layer of silicon dioxide, a metallization system comprising a plurality of conductors, each conductor comprising a first layer of titanium, a second layer, of platinum or palladium, and a third layer of gold, and a pyrolytically-deposited silicon dioxide protective coating having a thickness of at least 10,000 A over said metallization system, a plurality of leads, each having a portion adjacent to said silicon body, means for interconnecting said metallization system with said plurality of leads, and a transfer molded body of polymeric material surrounding said silicon body, said interconnecting means, and parts of said leads, whereby the combination of the silicon dioxide protective coating and the surrounding transfer molded body of polymeric material protects the metallization system to prevent degradation thereof.