Low Pressure and Short-Time Silver-Sintering for Power Modules

Abstract

Silver-sintering has become one of the main chip interconnect technologies in wide bandgap (WBG) semiconductor power modules due to its excellent thermal conductivity, high temperature stability and mechanical reliability. However, the traditional silver sintering process generally has the problems of long sintering time and high auxiliary pressure, which not only restricts the industrial production efficiency, but also may cause mechanical damage to the brittle chip. In this study, an innovative low-pressure and short-time silver sintering process, namely the Paste+Film method, was proposed and systematically verified. Through controlled experiments, the results showed that the Paste+Film method can achieve high-quality silver connections with a shear strength of more than 40MPa under the conditions of only applying a mild pressure of 5–10 MPa and shortening the sintering time to 3–5 minutes. In addition, the process was successfully applied to the packaging preparation of double-sided cooled SiC MOSFET half-bridge modules, and the overall sintering time was shortened by about 75% compared with the traditional method. Electrical testing and mechanical performance evaluation further verified the superiority of the Paste+Film process in ensuring chip structural integrity, improving process yield and material utilization, and provided a new path for achieving large-scale manufacturing of next-generation high-power density and high-reliability power modules.