MICROSTRUCTURE AND MECHANICAL PROPERTIES OF SOME LEAD FREE SOLDER ALLOYS IN RELATION TO THERMAL DEFORMATION

In recent years, the pollution of environment from lead (Pb) and Pb-containing compounds in microelectronic devices attracts more and more attentions in industry. The lead-free solder alloys begin to replace the lead-based solders in packaging process of In this study, the effects of Ag- and Au- additions on microstructure, thermal, and mechanical properties of Sn-5Sb-based solder alloy were investigated. The results showed that the microstructure of Sn-5Sb binary alloy is characterized by the presence ofTensile stress-strain tests were performed under constant strain rate of 1.3 x 10-2 s-1 at various temperatures ranging from 50 to 130 oC with 20 oC increments, and also conducted at constant temperature of 80 oC and various strain rate, ranging from 3.8 For Sn-5Sb-1.5Au alloy, an apparent activation energy of 136.0 kJ/mol for the entire stress range is close to activation energy of lattice self-diffusion (123.0 kJ/mol). On the other hand, activation energy for Sn-5Sb-3.5Ag and Sn-5Sb alloys are 85.5 and Creep is the most important deformation mechanism, which must be analyzed in order to understand the reliability characteristics of solder joints. In this study the steady state creep behaviour of the three solder alloys were also investigated in the stre