In order to investigate the use of Sn-8Zn-3Bi solder as a potential substitute for Sn-Pb solder, which has a lower melting point than Sn-Ag family solders for CSP assembly, we studied mechanical properties of CSP joints plated with varying thicknesses of Au and Ni on Cu pad. Joint strength and other mechanical properties were evaluated in relation to reflow peak temperature. The combination of 0.05 mm Au plating thickness and reflow peak temperature of 498 K resulted in the best joint reliability in the as reflowed condition and also after aging treatment. The joint was founded to have thin Ni 3 Sn 4 type interfacial reaction layer that included Cu and Zn between the solder and the Ni plating. This interfacial structure was shown to improve the joint strength.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.