Comparison of Pd-42Cu-10Ni and Pd-30Cu-29.5Ag-0.5Zn as Probe Material in Interfacial Reaction with Sn

A test probe is used for continuity test of semiconductor packages with solder balls. The probe material is often damaged due to solder adhesion on it by repeated test. The Pd-42Cu-10Ni (mass%) alloy has been developed as a substitute material for the conventional Pd-30Cu-29.5Ag-0.5Zn (mass%) alloy. The interfacial reaction between Pd-42Cu-10Ni and Sn by aging at 150°C was investigated in this study. Moreover, the obtained data was compared to those of the conventional alloy. As a result, it was confirmed that granular (Cu,Ni) 6 Sn 5 forms at the interface between the reaction layer and Sn, and the reaction layer consists of stacked layers of the PdSn 4 +PdSn 3 layer and the (Cu,Ni) 6 Sn 5 +Cu 3 Sn+PdSn layer. The reaction layer mainly grew toward the Sn side from the original interface. Furthermore, the thickness of the reaction layer grown by aging was suppressed to approximately one-fourth compared with the conventional alloy.