Low temperature, low pressure, fluxless and plateless Cu-Cu bonding by Cu nano particle transient liquid phase sintering

Abstract

In this work, low temperature of 200 °C, low pressure of 0.1MPa, fluxless and plateless Cu-Cu bonding in SiC power module is achieved by the transient phase liquid sintering (TLPS) of Cu nano particle and Sn-Bi eutectic powder. In this paper, shear strength at room temperature and 150 °C of two compositions of Cu mixed with Sn-Bi is investigated and the factor influencing the shear strength at 150 °C is examined by means of differential scanning calorimetry (DSC). In 70 mass% added Sn-Bi (Cu-70SnBi), which was sintered at 200 °C, the remelting event at 139 °C occurred due to the residual Sn-Bi eutectic phase and assumed to result in the decrease of shear strength at 150 °C. On contrary, in 65 mass% added Sn-Bi (Cu-65SnBi), which was sintered at the same conditions, remelting event at 139 °C was not observed, and the obtained shear strength at 150 °C was almost similar to that of at room temperature (R. T.).