Nanocomposite SAC solders: the effect of heat treatment on the morphology of Sn-3.0Ag-0.5Cu/Cu solder joints reinforced with Ni and Ni-Sn nanoparticles

The concept of nanocomposite lead-free solders has provided a promising approach to improve mechanical reliability of solder joints. Minor additions of metal nanoparticles into the commonly used Sn-3.0Ag-0.5Cu solder impact on the morphology of both the solder alloy and solder/Cu joint. For instance, it was stated that the average thickness of the interfacial intermetallic compound layer between Sn-3.0Ag-0.5Cu solder and Cu substrate decreases by addition up to 2.0wt.% of nano-sized Ni and Ni-Sn particles. The present research is the follow-up of our previous study and is focused on the investigations of the thermal aged Sn-3.0Ag-0.5Cu solder joints with up to 2.0wt.% of nano-sized Ni, Ni3Sn and Ni3Sn2 inclusions. The produced Cu/nanocomposite solder/Cu joints were kept at the temperature of 423 K for 10 and 20 days. Based on the average thickness of the interfacial intermetallic compound layer Cu6Sn5/Cu3Sn estimated for solder joints with different aging time, the growth kinetics of the interfacial IMC layer was examined.