Highly Reliable Polyimide-based Thermal Interface Material Sheets for Power Modules

Miniaturization of power modules in xEVs is progressing, but there are still several thermal management challenges toward higher power density of it. Direct bonding by using a flexible thermal interface material (TIM) between a heat sink and a packaging is one of promising methods to achieve excellent reliability and heat dissipation. In this study, we have developed the TIM sheet made from polyimide and fillers to achieve high thermal conductivity, insulation, and adhesion. It was found that TIM-C, the lowest elasticity and the highest tensile elongation among tested samples, showed excellent solder reflow resistance and thermal cycle reliability.