POLYMER AND METAL MATRIX COMPOSITES FOR THERMAL MANAGEMENT IN ELECTRONIC DEVICES

GRAPHITE FIBER WITH THERMAL CONDUCTIVITY THREE TIMES COPPER, HIGH MODULUS AND NEGATIVE THERMAL EXPANSION WILL BE USED TO DEMONSTRATE THE USE OF BOTH ALUMINUM AND ORGANIC MATRICES FOR THE SEM D HEAT SINK. COMPOSITES WILL BE TAILORED TO MATCH THE THERMAL EXPANSION OF THE PRINTED WIRING BOARD AND ALTERNATIVELY, TO PROVIDE A MAXIMUM THERMAL CONDUCTIVITY IN THE DIRECTION OF HEAT FLOW. FIBERS WILL BE USED THROUGH THE CURVATURE OF THE SEM D HEAT SINK. FOR ORGANIC MATRIX COMPOSITES, A COPPER-COATED GRAPHITE FIBER TOW WILL MAXIMIZE THERMAL CONDUCTIVITY AND PREVENT FIBER FRAYING AT THE CURVATURE. IN METAL MATRIX, THE EFFECT OF FRAYING AT THE CURVATURE ON MECHANICAL PROPERTIES WILL BE MINIMIZED BY THE USE OF A CLOTH PREFORM. THERE SHOULD BE NO DEGRADATION OF THERMAL CONDUCTIVITY. THE THICKNESS OF THE METAL MATRIX COMPOSITE IN CONTACT WITH THE PRINTED WIRING BOARD WILL BE A CONTROLLED VARIABLE. EVALUATION WILL BE CARRIED OUT USING A SEM SIMULATOR AND SURFACE STRAIN MEASUREMENTS. MEASUREMENTS WILL BE MADE BEFORE AND AFTER THERMAL CYCLING. THE POTENTIAL IMPACT OF THE COMPOSITE CONCEPT ON MODULE RELIABILITY AND WEIGHT SAVING WILL BE ASSESSED. THE PHASE II PROGRAM WILL EMPHASIZE PROPERTY PRODUCIBILITY, DATA BASE DEVELOPMENT, AND DEMONSTRATION OF HEAT SINK PERFORMANCE IN ACTUAL SEM E DEVICES.