Thermal shock reliability of micro–nano bimodal Cu–Ag sintered joints

Abstract

In this study, we investigated the thermal shock reliability of die-attach technology using a micro–nano bimodal Cu–Ag paste, which can considerably reduce material costs compared with a nano-Ag paste. A reliability study of Cu-sintered joints can facilitate large-scale applications in the electric vehicle industry as only a few systematic studies have investigated the thermal shock reliability of low-cost Cu-sintered joints. To evaluate the thermomechanical stability and bond strength of the Cu–Ag sintered joints, a thermal shock test between − 40 and 150 °C for 1000 cycles and die shear tests, respectively, were performed. The thermal shock test results clearly demonstrated that the micro–nano bimodal Cu–Ag sintered joints maintained a high strength (60 MPa) for 1000 cycles. The bimodal Cu–Ag paste die-attach is reliable because of stable microstructures that are free of cracks and interfacial debonding. The results showed that our bimodal Cu–Ag paste die-attach can be used in both Si and SiC power devices operating at high temperatures.