Improvement of microstructure and interface structure of eutectic Sn-0.7Cu solder with small amount of Zn addition

With small amount of Zn addition, a refined microstructure of bulk Sn-0.7Cu solder alloy has been obtained. Meanwhile, retardation effect has been observed on the growth of IMC layer at the solder/Cu joint interface. The composition variation of the interface IMC layer with the amount of Zn addition is reported and thermodynamically analyzed.