Silver-Copper Hybrid Nanocomposite Thermal Interface Materials for Power Electronic Device Packaging

Thermal interface materials (TIMs) play a crucial role in the thermal management of power electronic devices. In this study, a new class of TIMs, the silver-copper micro-nano hybrid composite pastes (AgCuMNH), was presented utilizing the sizes and shapes the materials natural properties of copper microparticles (CuMPs), silver nanoflakes (AgNFs), and silver nanoparticles (AgNPs), to form the low temperature sintering Ag-Cu hybrid nanocomposites, which demonstrated superior thermal conductivity up to 330.0 W/(m·K) under the process conditions of 220 ℃ of temperature and 0.7 MPa of pressure. It was found that the solvent choices would play a significant role in the paste formulation since the polarity of solvent highly affect the disperse and distribution of the silver nanoparticles and nanoflakes in the pastes, which dictated the degree of sintering in the hybrid nanocomposites and hence showed large differences in material thermal and electrical conductivities. To further validate the AgCuMNH as high performance TIMs for power electronic device packaging, they were used as the die-attach pastes for a model LED chip packaging structure. The thermal resistance of AgCuMNH as the die-attach TIMs was 0.56 K/W. Compared with the best commercially available low-temperature sintered silver paste from Kyocera (CT2700R7S), whose thermal resistance in the same device was measured to be 1.00 K/W in the parallel tests, there were more than 40% improvement in performance as the TIMs for packaged devices.