METAL MATRIX COMPOSITE HEAT SINK WITH INTEGRAL DIELECTRIC

HIGH DENSITY ELECTRONIC CIRCUITS REQUIRE SPECIAL CONSIDERATIONS WITH RESPECT TO THERMAL MANAGEMENT. ALONG WITH HEAT REMOVAL, MOST ELECTRONIC ASSEMBLIES REQUIRE SUBSTRATES OF CONTROLLED THERMAL EXPANSION. ALSO, THE DESIGN OF VHSIC ASSEMBLIES USUALLY IMPOSES SIZE AND WEIGHT REQUIREMENTS. EACH OF THE DIELECTRIC MATERIALS THAT IS NOW IN USE OFFERS SOME OF THESE FEATURES, BUT NONE OFFERS A COMBINATION THAT RESPONDS TO ALL OF THESE NEEDS. WE PROPOSE THE USE OF A CLAD ALUMINUM METAL MATRIC COMPOSITE SUBSTRATE. THE METAL MATRIX COMPOSITE OFFERS A COMBINATION OF LIGHT WEIGHT, LOW COEFFICIENT OF THERMAL EXPANSION, HIGH THERMAL CONDUCTIVITY AND MECHANICAL STRENGTH. THIS UNIQUE SET OF PROPERTIES RESULTS IN A STRONG SUBSTRATE THAT SERVES AS WELL AS A HEAT SINK. THE EXPANSION COEFFICIENT OF METAL MATRIX COMPOSITES IS TAILORABLE, AND THIS ALLOWS THE USE OF CIRCUIT DESIGNS WHERE SILICON OR GAAS DEVICES CAN BE MOUNTED DIRECTLY ON THE HEAT SINK. IN THIS APPLICATION, THE CLAD LAYER ON THE METAL MATRIX COMPOSITE IS CHEMICALLY CONVERTED TO A DIELECTRIC, AND THIS INTEGRAL LAYER IS TREATED BY INFILTRATION, IMPREGNATION OR OVERLAYERS TO ENHANCE DIELECTRIC PROPERTIES.