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.