Ultra-low-temperature lead-free multicomponent alloy solder for application in heat-sensitive electronic components

Abstract

This manuscript describes the development of a lead-free multicomponent solder alloy composed of Sn, Bi, In, Cu, and Zn for heat-sensitive electronic devices. The microstructure comprises a homogeneous distribution of CuZn particles embedded in a eutectic mixture of Sn (solid solution) and InBi with a melting temperature of 83.7 °C. The average thickness of the generated intermetallic compounds between solder/substrate (Cu) was < 4 µm with a wetting contact angle below 55°, which is acceptable in the electronic industries. Additionally, the solder's shear stress (12.94 ± 1.50 MPa) is lower than commercial counterparts; but it shows a much higher shear strain (0.53 ± 0.06 mm/mm). Thus, the developed system could have great potential for applications in ultra-low-temperature lead-free solders.