Microelectronic packages

Claim 1

A heat dissipating package assembly for a microelectronic circuit chip wherein no thermal treatment or contact of the chip with encapsulating media is required after the chip is mounted and connected within the assembly, said package assembly comprising: a thermally conductive plate of metal serving as a base for mounting of the chip thereon; a lead frame assembly comprising a first insulating sheet and a second insulating sheet in face to face relationship, each such sheet being made up or a mass of glass fibers impregnated with a thermoset resin and a plurality of electrically conductive leads each having a flat portion disposed between and bonded to said insulating sheets by said resin, said first insulating sheet having bonded to said base that face opposite the one facing said second insulating sheet and having an opening therein leaving exposed an area of said base sufficient to receive the chip when it is mounted on the base, said leads being so arranged as to present first ends disposed adjacent said opening for bonding thereto of connections from the chip, said leads each having an opposite end located outside the package and serving as an external terminal, said second insulating sheet having an opening therein larger than and encompassing the opening in the first sheet so as to leave exposed said first ends of said leads to permit establishing connections to said chip; and mechanical means for enclosing the chip, the face of the base on which the chip is mounted, and the leads except for said external terminals while leaving exposed the opposite face of the base to permit heat to be dissipated therefrom.