Performance comparisons for electrically conductive epoxies in wireless applications

The thermal conductivity of electrically conductive epoxies is usually the most important factor when considering new epoxy materials for die attach in wireless applications. Some recently developed epoxies with improved mechanical and electrical properties were studied. A combination of numerical modeling, simulation and measured data were used to determine the trends between the thermal, mechanical and electrical performance of various die attach epoxies. The thermal simulation results indicated that the higher (20 W/mK) thermally conductive epoxy provides only a slight improvement (less than 10/spl deg/C) in thermal performance when considered against the lower (8 W/mK) thermally conductive epoxy. By comparison, the electrical conductivity of the higher thermally conductive epoxy was lower by an order of magnitude than the lower thermally conductive epoxy. Also during the moisture sensitivity level testing (MSL), the higher thermally conductive epoxy exhibited some degree of delamination while the lower thermally conductive epoxy exhibited no delamination. The study revealed that the improved mechanical and electrical properties reduce the reliance on the thermal property as the most important factor in the selection of electrically conductive epoxies.