Emerging issues in the physics and control of electromigration in SnPb and Pb-free solder bumps

摘要: Electromigration is the movement of metal atoms in direction current flow. It caused by transfer momentum from passing electrons to lattice. First discovered thin-film aluminum conductors some thirty years ago, electromigration a significant concern for solder bumps on chip scale packages (CSP). As understanding expands, new opportunities risk mitigation have emerged. This paper addresses physics solders with particular emphasis time and temperature dependant factors that affect accelerated testing. Pb-based are contrasted Pb-free realizing microstructures these substantially different risks as well.