Abstract
This study aims to investigate the interfacial reactions and cross-interaction of Ni/Sn-3.0Ag-0.5Cu/Cu-xZn (Ni/SAC/Cu-xZn; x = 0, 15, and 30 wt.%) solder joints. In comparison with the Ni/SAC/Cu solder joint, Ni/SAC/Cu-15Zn and Ni/SAC/Cu-30Zn solder joints revealed thinner Cu 6 Sn 5 -based intermetallic compounds (IMCs) at both Ni/SAC and SAC/Cu-Zn interfaces after aging at 150°C for 40 days. (Cu,Ni) 6 (Sn,Zn) 5 /(Cu,Ni) 6 Sn 5 dual-phase formed at the Ni side, while (Cu,Ni) 6 (Sn,Zn) 5 single-phase at the Cu-Zn side. Interestingly, the interfacial IMCs grew very slowly, and no void formed in these Zn-contained solder joints during the heating process. Also, the dissolved Zn in the solder alloy reduced the elemental cross-interaction between Ni and Cu-Zn substrates. The noticeable thermal stability of Ni/SAC/Cu-Zn solder joints is attributed to the Zn redistribution retarding the reaction of Ni, Cu and Sn. Phase formation and IMCs suppression mechanisms in Ni/SAC/Cu-Zn solder joints were probed and discussed. © 2012 Published by Elsevier Ltd. All rights reserved.