Micro-flake Ag paste sinter joining on bare DBA substrate for high temperature SiC power modules

Abstract

In this study, Ag flake particles paste sinter joining on a bare DBA (Al/AlN/Al) substrate at temperature of 250 °C without pressure was achieved with a robust shear strength of 33.6 MPa in a SiC power module. The microstructure of sintered Ag and the bonded interface of Ag/Al indicated that the excellent sinter ability of the Ag paste. The Ag nanoparticles were in-situ-formed from the Ag flake particles, which tight bonding to the Al surface. High-temperature reliability of the SiC-DBA joint structure were investigated by high-temperature aging at 250 °C, and thermal shock test from -50 to 250 °C. The shear strength still larger than 30 MPa after 1000 h aging. Large deformation of Al layer occurred after thermal shock test, leading to the interface cracks generation and shear strength decrease.