Patent ID: 7459346

Claim:
A method of fabricating a semiconductor device, comprising: applying a heat sink layer onto a first surface of a support substrate having a thickness and a thermally conductive via interconnect extending therethrough, the heat sink comprising a thermally conductive material and having a thickness greater than the thickness of the support substrate, the heat sink layer in conductive contact with the thermally conductive via interconnect; forming a soldermask layer directly on the heat sink layer; forming a conductive plane layer on a second surface of the support substrate, the conductive plane layer comprising conductive traces and a plurality of ball bonding pads, each trace connected to a ball bonding pad, and the thermally conductive via interconnect connected to a ball bonding pad but not to a trace; mounting a semiconductor die on the soldermask layer; and mounting a plurality of ball contacts onto the ball bonding pads; wherein heat from the die passes through the heat sink layer, the via interconnect, and the ball contact connected to the via interconnect but not into the ball contacts connected to the traces, and the ball contact connected to the via interconnect is not electrically connected to the die.