Study of IMC morphologies and phase characteristics affected by the reactions of Ni and Cu metallurgies with Pb-free solder joints

The presence of a Cu layer either under or over the Ni layer was evaluated by varying the thickness of Cu and Ni. The type of Ni plating, either electrolytic or electroless, serving as a reaction/diffusion barrier, was also investigated. Overall, the results provide a detailed understanding of the interfacial reactions, which leads to the designing of a more reliable metallurgical system for Pb-free solder joints.