“…In recent years, environmental concerns, legislation, and even customer preferences are propelling the microelectronics industry towards implementation of lead-free solder alloys [3,4]. Among all Pb-free solder alloys, the Sn-Cu solder system, which shows good mechanical properties (ductility, creep resistance and thermal resistance), electrical properties and low cost, is proven to be one of the most promising Pb-free candidates for electronic assembly, compared with other Sn-based solder systems [5][6][7]. During soldering process, the intermetallic compounds (IMCs) are generally formed at the Sn-Cu solder/Cu interface [8,9].…”