Pd-doped Sn–Ag–Cu–In solder material for high drop/shock reliability

Pd was chosen as a minor alloying element in a new Sn–1.2Ag–0.7Cu–0.4In solder alloy to improve the drop/shock reliability. The tensile properties and drop/shock reliability of the new Sn–1.2Ag–0.7Cu–0.4In–0.03Pd solder alloy was compared with those of the Sn–1.0Ag–0.5Cu and Sn–3.0Ag–0.5Cu alloys. The UTS, yield strength and elongation of Sn–1.2Ag–0.7Cu–0.4In–0.03Pd were superior to those of the other alloys tested. Sn–1.2Ag–0.7Cu–0.4In–0.03Pd showed outstanding drop/shock reliability compared to the representative Pb-free solder, Sn–3.0Ag–0.5Cu. Therefore, the Sn–1.2Ag–0.7Cu–0.4In–0.03Pd composition is assessed to be an alternative Pb-free solder composition that may replace Sn–3.0Ag–0.5Cu.