Electrochemical composite deposition of Sn–Ag–Cu alloys

The dominant materials used for solders in electronic assemblies over the past 60 years have been Pb–Sn alloys. Increasing pressure from environmental and health authorities has stimulated the development of various Pb-free solders. One of the most promising replacements is eutectic or near-eutectic Sn–Ag–Cu alloys produced by electrodeposition. In this study, simple and “green” Sn–Cu-citrate solutions with suspended Ag particles have been developed and optimized for electrochemical composite deposition of eutectic and near-eutectic Sn–Ag–Cu solder films. Different plating conditions, including solution concentration, current density, agitation and additives, are investigated by evaluating their effects on plating rate, deposit composition and microstructure.