The nucleation-controlled intermetallic grain refinement of Cu-Sn solid-liquid interdiffusion wafer bonding joints induced by addition of Ni particles

Abstract In this study, Ni particle was validated as an effective grain refiner for the Cu-Sn solid-liquid interdiffusion (SLID) wafer bonding joints, which induced a dispersive non-interfacial nucleation of intermetallic grains, effectively preventing the grain mergence phenomenon. With increasing the Ni particle addition, there were significant reductions in both the (Cu, Ni) 6 Sn 5 grain size and the Cu 3 Sn layer thickness, 6 wt% addition of Ni particles even led a formation of the intermetallic joints only consisted of (Cu, Ni) 6 Sn 5 grains with an average grain size of 1.3 μm. (Cu, Ni) 6 Sn 5 grain refinement could notably enhanced the shear strength of the intermetallic joints.