Effect of Ag content and the minor alloying element Fe on the electrical resistivity of Sn–Ag–Cu solder alloy

•The electrical resistivity of Sn–Ag–Cu solder is affected by the content of Fe and Ag.•The electrical resistivity increases with decreasing the Ag content.•Adding 0.1 wt.% Fe to the SAC105 solder reduces the electrical resistivity.•Fe-added SAC105 solder exhibits comparable electrical performance to support mechanical performance.

In this paper, we investigated the electrical resistivity of the high-Ag-content Sn–3Ag–0.5Cu, the low-Ag-content Sn–1Ag–0.5Cu solder alloy, and the three quaternary solder alloys Sn–1Ag–0.5Cu–0.1Fe, Sn–1Ag–0.5Cu–0.3Fe, and Sn–1Ag–0.5Cu–0.5Fe. The electrical resistivity was characterized by the four-point probe technique. The results show that both the Ag content and the addition of Fe significantly affected the electrical resistivity. The electrical resistivity was found to increase with a reduction in the Ag content in the solder alloy. The electrical resistivity of Fe-modified Sn–1Ag–0.5Cu solder alloys decreased initially with the addition of 0.1 wt.% Fe, and then gradually increased with 0.3 wt.% and 0.5 wt.% Fe addition. Microstructural changes resulting from the content of Ag and the addition of Fe have been correlated to the electrical resistivity change.