Challenges in converting to lead-free electronics

For the effective migration to lead-free electronics, the industry must ide ntify a number of lead-free compatible solders, establish an effective asse mbly process temperature hierarchy, and have a large number of components t hat 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 th e challenges in making packages compatible with the higher solder temperatu res associated with lead-free solders. We also briefly review the lead-free materials direction and challenges for solder ball interconnects, componen t termination and board finishes.