Reduction of electromigration damage in SAC305 solder joints by adding Ni nanoparticles through flux doping

The characteristics of interfacial intermetallic compounds (IMCs) can have serious impact on the reliability of solder joints. In this study, Ni nanoparticles (NPs) were added to SAC305 solder/Cu substrate interface by flux mixing. The effects of Ni NP addition on electromigration (EM) under high current density were investigated. EM tests with a maximum duration of 1128 h were conducted under a current density of 1 × 10⁴ A/cm², at 80 ± 3 °C on the solders prepared using 0 and 2 wt% Ni NPs-doped flux. At 2 wt% Ni NPs addition to flux, the growth rate of interfacial IMC at the anode side decreased by more than five times. No significant change in electrical resistance was observed in 2 wt% samples for up to 1128 h. Ni NP addition at the solder/substrate through flux mixing is, therefore, expected to lead to more reliable solder joints.