材料期刊网

In the current study, the interfacial microstructures of Sn-Ag/Cu-X alloy (X = Ag, Sn or Zn) couples were investigated. The experimental results confirm that addition of Ag or Zn can effectively suppress the growth of the Cu(3)Sn layer, while addition of Sn accelerates the growth of the Cu(3)Sn layer. Meanwhile, the formation of voids is effectively suppressed by alloying the Cu substrate. The disappearance of voids and the absence of the Cu(3)Sn layer were well explained in terms of the phase diagram and the diffusion flux: the Cu(3)Sn phase is a nonequilibrium phase based on the Sn-Cu-Zn ternary phase diagram, since a high-Zn region is formed at the Cu(6)Sn(5)/Cu-Zn alloy interface; in addition, the high Sn diffusion flux in the Cu(6)Sn(5) can suppress the growth of Cu(3)Sn and the formation of voids.