Challenges in converting to lead-free electronics

For effective migration to lead-free electronics, the industry must identify a number of lead-free compatible solders, establish an effective assembly process temperature hierarchy, and have a large number of components that are compatible with this thermal hierarchy. In this paper, we propose a temperature hierarchy for lead-free reflow soldering, discuss the critical factors in developing an optimal lead-free reflow profile, and identify the challenges in making packages compatible with the higher solder temperatures associated with lead-free solders. We also briefly review the lead-free materials direction and challenges for solder ball interconnects, component termination and board finishes