Interfacial microstructure and properties of Sn–0.7Cu–0.05Ni/Cu solder joint with rare earth Nd addition

Development of high strength Sn–0.7Cu solders with the addition of small amount of Ag and In

“…The melting point of eutectic composition is relatively high (227 • C) when compared to the Sn-Pb (183 • C) [8]. Nevertheless, there has been only a limited amount of data about the mechanical properties of Sn-Cu solder and its joint [9,10].…”

“…Also, the tensile and shear strength of Sn-Cu eutectic solder were found to be inferior to those of Sn-Ag and Sn-Ag-Cu eutectic solders. Interestingly, it was also found that the Sn-Cu eutectic alloy has substandard mechanical properties when compared with other lead-free solders and even with Pb-Sn solders [10]. On the other hand, the Sn-Cu Pb-free solder joints typically have a bad solder joint appearance, insufficient oxidation resistance characteristic that can be more of issues for wave soldering applications [12].…”

“…On the other hand, the Sn-Cu Pb-free solder joints typically have a bad solder joint appearance, insufficient oxidation resistance characteristic that can be more of issues for wave soldering applications [12]. Thus, it is expected to improve its mechanical properties and oxidation resistance performance by adding trace amount of elements such as; Ag [10,11], P [11] and Mo [13]. Chuang et al [14] showed that by adding Ag into the Sn-Cu system, the melting temperature can be reduced from 227 • C to 217 • C, which reduces the magnitude of thermal stresses during soldering and improves the solder reliability.…”

“…Chuang et al [14] showed that by adding Ag into the Sn-Cu system, the melting temperature can be reduced from 227 • C to 217 • C, which reduces the magnitude of thermal stresses during soldering and improves the solder reliability. In addition, the high Ag content and strong Cu 6 Sn 5 phases of a well designed Sn-Ag-Cu alloy solder can promote enhanced joint strength and creep resistance [10]. Li et al [11] also showed that the trace P addition into Sn-Cu alloy can increase the rate of forming void of Sn-0.7Cu solder joint, which can potentially enhance crack initiation in the solder joint.…”

Effect of Trace Ge on Wettability and High-Temperature Oxidation Resistance of Sn-0.7Cu Lead-Free Solder

“…Therefore, it will not only produce a lot of wastes, but also increase the defects probability of solder joint for wave soldering applications which would seriously affect the reliability of soldering joints 3) . Thus, it is expected to improve its wettability and oxidation resistance performance by adding trace amount of elements such as; P 4,5) , Ag 3,6) , and Al 7) . However, these studies generally are centered on low temperature around 260 C. Electronics manufacturers sometimes need to use the same solder in a wider temperature range in the actual production process, such as 250 C 400 C. So the research on wettability and oxidation resistance of solder at high temperature is particularly important.…”