ABSTRACT
Soldering technology plays a key role in various levels of electronic packaging, such as solder joints in printed circuit boards (PCB) formed by either surface mount soldering or platedthrough-hole (PTH) soldering of components, flip-chip connections, attaching heat sinks, and others. Solder joints in electronic packages serve as electrical interconnections and provide mechanical/physical support.When either of these requirements cannot bemet, the solder joint is considered to have failed, which can cause the failure of the entire electronic system. Lead (Pb)- containing solders, such as 63Sn-37Pb, Pb-10Sn, andPb-3Sn (all in weight%), have been used in various microelectronic applications. The research and development activities for replacing Pbcontaining solders with Pb-free solders have been intensified due to both competitive market pressures and environmental issues.
