Heat-dissipating package for microcircuit devices

Abstract

High density heatsinks for microcircuit packages are formed by first mold-pressing a composite powder of free-flowing spray-dried particles of an inexpensive high thermal conductivity material having a high coefficient of thermal expansion (CTE) such as copper and at least one other low CTE material such as tungsten, the proportions of which are adjusted to match the CTE of the microcircuit material. The pressed compacts are sintered in order to achieve an homogeneous distribution of the melting copper throughout the structure. A multilevel embodiment of the heatsink comprises two bonded layers of metals or composites having their coefficients of thermal expansion adjusted to match those of the semiconductor material and of any supporting structures respectively, wherein the second layer in contact with the supporting structure has a high CTE and the other has a lower CTE. Another embodiment provides for bonding a composite heatsink to a high thermal conductivity pedestal which mounts the microcircuit device, using sintering to shrink an aperture engaged by the pedestal.

Dependencies are inferred from the claim text.