Interfacial thermal resistance and temperature dependence of three adhesives for electronic packaging

Abstract

The thermal resistance and its temperature dependence was measured for three industrial adhesives used for electronic packaging. Measurements were made by the laser-flash method from room temperature to 300/spl deg/C. The samples were in the form of sandwiches consisting of two platelets of silicon carbide-reinforced aluminum (AlSiC) bonded together with the adhesives. The total thermal resistance of the bond (the sum of the bulk thermal resistance of the adhesive and the resistances at the two interfaces) was calculated from the thermal response of the sandwich subjected on one side to a single laser-flash. The total thermal resistance was found to decrease with increasing temperature. The bulk thermal resistance of the adhesive, calculated from its thickness and independently determined thermal conductivity, was found to be relatively independent of temperature. The interfacial resistance at the AlSiC interfaces, depending on the adhesive, ranged from about 60 to 80% of the total resistance decreasing to about 50% of the total interfacial resistance at 300/spl deg/C. For two of the adhesives considered in this study, the interfacial thermal resistances for the AlSiC/adhesive interfaces were found to be considerably higher than those found in an earlier study of Si/adhesive interfaces.