Compact power semiconductor device and method of making same

Claim 1

A compact high power semiconductor device bridge assembly which comprises at least two proximate spaced mutually insulated heat sinks, said heat sinks having facing surfaces with at least one recess in each of said surfaces, each of said recesses being of a given depth, side and end walls in each of said recesses, a disk of copper in each of said recesses, said disk having two faces spaced by a circumferential edge of a given thickness, said thickness being substantially less than the depth of said recesses, one face of said disk abutting said end wall and said disk edge engaging said recess side wall to wedge said disk in place, a wafer of semiconductive material supported on each of said copper disks, each of said wafers having a PN junction therein separating its two major faces, silicone rubber sealing said recesses, discrete terminal leads electrically contacting each of said wafers and extending out of said recesses through said silicone rubber, a conductive stud interconnecting terminal leads from said recesses in said facing surfaces, said stud being electrically insulated from said heat sinks, complementary pairs of transverse undercut grooves in said facing surfaces on opposite sides of said recesses, a nonconductive retainer element interlocked within each of said complementary pairs of grooves thereby forming a cavity between said heat sinks, said nonconductive retainer element having an X-shaped cross section and a longitudinal extension substantially across the heat sinks serving as a damming for a plastic resin therebetween, a plastic resin filling the cavity between the heat sinks and said insulating members, and means on said heat sinks to enhance adhesion of the said plastic resin to said heat sinks.