|Title:||Electromigration and Thermomigration in Pb-Free Flip-Chip Solder Joints|
Tong, H. M.
Tu, K. N.
Department of Materials Science and Engineering
|Keywords:||microelectronic packaging;diffusion;reliability;current stressing;Joule heating;thermal gradient;underbump metallization|
|Abstract:||Pb-free solders have replaced Pb-containing SnPb solders in the electronic packaging industry due to environmental concerns. Both electromigration (EM) and thermomigration (TM) have serious reliability issues for fine-pitch Pb-free solder bumps in the flip-chip technology used in consumer electronic products. We review the unique features of EM and TM in flip-chip solder bumps, emphasizing the effects of current crowding and joule heating. In addition, the challenges to a better understanding of EM and TM in Pb-free solders are discussed. For example, the anisotropic nature of Sn microstructure in Pb-free solders can enhance the dissolution rates of Ni and Cu in solders driven by EM and TM.|
|Journal:||ANNUAL REVIEW OF MATERIALS RESEARCH, VOL 40|
|Appears in Collections:||Articles|
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