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

The thermal resistance and its temperature dependence was measured for thre e industrial adhesives used for electronic packaging. Measurements were mad e by the laser-flash method from room temperature to 300 degreesC. The samp les were in the form of sandwiches consisting of two platelets of silicon c arbide-reinforced aluminum (AlSiC) bonded together with the adhesives. The total thermal resistance of the bond (the sum of the bulk thermal resistanc e 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 singl e laser-flash. The total thermal resistance was found to decrease with incr easing 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 resistan ce 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 interf acial resistance at 300 degreesC. For two of the adhesives considered in th is study, the interfacial thermal resistances for the AlSiC/adhesive interf aces were found to be considerably higher than those found in an earlier st udy of Si/adhesive interfaces.