Facile Preparation of Cu-Ag Micro-Nano Composite Paste for High Power Device Packaging

In this paper, a novel Cu-Ag micro-nano composite particle (MNCP) paste was prepared, and a low temperature Cu- Cu bonding with high sheer strength was obtained. The microstructures and morphologies of the Cu-Ag MNCPs were systematically investigated. The surface chemical compositions of the composite particles displayed a little oxidized phenomenon, which could be reduced during sintering and bonding. After sintering at 275°C for 30 min under a low pressure, a sheer strength Cu-Cu bonding joint of 32.7 MPa was achieved. The fracture and cross-sectional microstructures of bonded joints exhibited obvious ductile characteristics and compact structure. These results manifested the Cu-Ag MNCPs are promising materials to fulfill the requirements of die-attach materials for high power device packaging.