Electrical resistivity of multicomponent Sn–Bi–In–Zn–Cu–Ag alloys as materials for low-temperature lead-free solders

Abstract

Low-melting lead-free solders play a crucial role in the step soldering process, which is commonly used in the fabrication of multi-chip modules as well as optoelectronic components. Since they help minimize thermal damage, they are also used to bond temperature-sensitive components in high-reliability electronics. Electrical resistivity of equiatomic multicomponent Bi-In-Sn-Zn, Bi-In-Zn-Sn-Cu and Bi-In-Sn-Zn-Cu-Ag alloys, as key characteristic of solders, has been investigated in a wide temperature range from room temperature to the liquid state with special attention to the melting-solidification region. The features of the resistivity behavior in the melting–solidification temperature range were confirmed by DSC and XRD analysis. Modification of binary and ternary Sn-, Ag-, Cu- based alloys with additional elements (Bi, In, Zn) can lower soldering temperatures.