Influence of Ni particle addition on grain refinement of Cu-Sn intermetallic compound joints bonded at various temperatures

In this study, the influence of 4 wt% Ni particles addition on the grain refinement of the Cu-Sn intermetallic compound (IMC) joints bonded by solid-liquid interdiffusion (SLID) bonding process at various temperatures was investigated. The addition of Ni particle could induce a dispersive non-interfacial nucleation of IMC grains during the bonding process, which could effectively prevent the grain mergence phenomenon, resulting in significant reductions in both the grain size of (Cu, Ni)6Sn5 grains and the layer thickness of Cu3Sn grains in the IMC joint. However, the magnitude of grain refinement induced by Ni particle addition exhibited an inverse relationship with the bonding temperature. Furthermore, there was an enhancement of the shear strength of the IMC joint due to the refinement of intermetallic grains.