Interfacial reaction of Cu/SnPbInBiSb/Cu sandwich solder joints

The high quality of 3D integrated circuit technology is in need of solder alloy with high reliability. To optimize the performance of solder alloys, the conception of high entropy alloy is introduced into the design of solder alloy. In this study, a new-style high entropy alloy SnPbInBiSb was prepared and investigated. This high entropy alloy has a wetting angle about 39.8 degrees and a melting temperature around 112.8 degrees C, thus it has a great potential to work as a new kind of low-temperature high entropy solder alloy. The interfacial reaction behavior of Cu/SnPbInBiSb/Cu sandwich joints was also investigated. The intermetallic compound Cu6Sn5 was transformed into Cu-6(Sn, Pb, In, Bi, Sb)(5) with the diffusion of Pb, In, Bi and Sb atoms. Moreover, the growth behavior of intermetallic compound was effectively restrained due to the effect of high entropy solder alloy.