Interface reaction between SnAgCu/SnAgCuCe solders and Cu substrate subjected to thermal cycling and isothermal aging

Highlights: → Interface reaction mechanism, experienced thermal cycling and isothermal aging, was carried out. → The growth kinetics which forming intermetallic compounds in both systems were also investigated under different aging conditions. → We found that the morphology of IMCs formed both at the solder/Cu interfaces was gradually changed from scallop-like to planar-like. → We found that rare earth Ce can refine the microstructures, decrease the thickness of the intermetallic compound layer. - Abstract: Trace amount of rare earth Ce (0.03 wt.%) was added into SnAgCu solder in order to reform the properties of the solder. In this study, interface reaction mechanism during thermal cycling and isothermal aging, was studied by studying the formation and growth of the intermetallic compound (IMC) at the solder (SnAgCu or SnAgCuCe)/Cu interface, and the growth kinetics which forming IMC in both systems (SnAgCu or SnAgCuCe) were also investigated under different aging conditions. The results show that the morphology of IMCs formed both at SnAgCu/Cu and SnAgCuCe/Cu interfaces was gradually changed from scallop-like to planar-like, and the thickness of different IMCs evolved with the increasing of aging time. The results also indicate that the growth rate of IMC at both interfaces during thermal cycling was higher than that during isothermal aging. Especially, the addition of amount of rare earth Ce into the SnAgCu solder can refine the microstructures; decrease the thickness of the intermetallic compound layer of SnAgCu solder alloys.