Low temperature sintering-bonding using mixed Cu+Ag nanoparticle paste for packaging application

In this study, the two kinds of nanoparticle pastes were prepared by using the modified polyol chemical reduction process, respectively, and the mixed nanoparticle paste was prepared by mechanically mixing of the two pastes. The sintering characteristics of the mixed paste were investigated, and the results show that the mixed paste had good oxidation resistance. Ag-coated copper bulks were bonded through the sintering of mixed paste. The results indicate that the increasing of Ag content in the paste was beneficial to high quality of joints, and with the bonding conditions of sintering at 250°C for 5 min under 5 MPa pressure, the average shear strengths of joints using nano-Cu paste, mixed paste consisting of 50% mole Ag and 50% mole Cu, and nano-Ag paste, were 15 MPa, 22 MPa and 56 MPa, respectively.