ADVANCED MATERIALS FOR ELECTRONIC PACKAGING APPLICATIONS

AS POWER REQUIREMENTS FOR ELECTRONIC DEVICES INCREASE, THE THERMAL EXPANSION MATCH BETWEEN THE VARIOUS COMPONENTS BECOMES AN IMPORTANT FACTOR IN DETERMINING RELIABILITY. FOR SEM E THIS INCLUDES THE SI CHIP, CASE, PRINTED WIRING BOARD (PWB), AND FRAME. THE INNOVATION IN THIS PROPOSAL IS TO MATCH THE THERMAL EXPANSION OF ALL FOUR OF THESE COMPONENTS USING ADVANCED MATERIALS, PARTICULARLY COMPOSITES. HIGH THERMAL CONDUCTIVITY MATERIALS WILL BE EMPHASIZED WHILE RECOGNIZING THE REQUIREMENT FOR DIELELECTRIC PROPERTIES IN SOME COMPONENTS. FOR THE CASE, ALN MATCHES SI IN THERMAL EXPANSION AND ALSO HAS BOTH EXCELLENT DIELECTRIC PROPERTIES AND HIGH THERMAL CONDUCTIVITY. ASSUMING A GLASS-EPOXY DIELECTRIC, THE PWB THERMAL EXPANSION MUST BE MATCHED TO CHIP AND CASE BY CONSTRAINING LAYERS. THE USE OF HIGH THERMAL CONDUCTIVITY GRAPHITE FIBERS WITH NEGATIVE THERMAL EXPANSION IN THESE LAYERS IS INDICATED. IN THE THERMAL PLANE, GRAPHITE FIBERS CAN BE USED IN CU OR AL MATRICES TO MATCH PWB THERMAL EXPANSION. IN PHASE I, MATERIALS WILL BE SELECTED FOR DEMONSTRATION BASED ON THE STATUS OF FABRICATION TECHNOLOGY AND POTENTIAL IMPACT ON DEVICE PERFORMANCE, RELIABILITY, AND COST. MEASUREMENT OF THERMAL CONDUCTIVITY AND THERMAL EXPANSION OF THE MATERIALS SELECTED WILL CONFIRM PREDICTED PROPERTIES. IN PHASE II THE VARIOUS DEVICE COMPONENTS WILL BE ASSEMBLED FOR QUALIFICATION TESTING.