Semiconductor package having multiple dies with independently biased back surfaces

Abstract

A thin, thermally efficient, lead frame-type of semiconductor package incorporating multiple dies includes a plurality of electrically conductive leads held together in a spaced, planar relationship about a central opening defined by the leads, and a plurality of thick, plate-like heat sinks supported within the opening such they are generally coplanar with each other, parallel to the plane of the leads, and electrically isolated from the leads and each other. Each of the heat sinks has a lower surface that can be exposed through the outer surface of a molded resin envelope encapsulating the package for the efficient dissipation of heat therefrom, and an upper surface having a recess formed into it. A semiconductor die is mounted in each of the recesses with its back surface in electrical connection with the floor of the recess. Each recess defines a wire bonding ring around the periphery of the upper surface of the respective heat sink immediately adjacent to the edges of the corresponding die for the bonding thereto of wires from the die and/or the leads. The package enables the back surface of each die to be independently biased to the same or a different electrical potential, provides enhanced heat dissipating capabilities and an improved resistance to penetration by moisture, and yields a wire-bonding region that substantially shortens the length of wires bonded thereto and reduces the residual shear stresses acting on the bonds.