Electromigration issues in lead-free solder joints

Chih Chen*, S. W. Liang

*Corresponding author for this work

研究成果: Chapter同行評審

13 引文 斯高帕斯(Scopus)


As the microelectronic industry advances to Pb-free solders due to environmental concerns, electromigration (EM) has become a critical issue for finepitch packaging as the diameter of the solder bump continues decreasing and the current that each bump carries keeps rising owing to higher performance requirement of electronic devices. As stated in 2003 International Technology Roadmap for Semiconductors (ITRS), the EM is expected to be the limiting factor for high-density packages. This paper reviews general background of EM, current understanding of EM in solder joints, and technical hurdles to be addressed as well as possible solutions. It is found that the EM lifetimes of Pb-free solder bumps are between the high-Pb and the eutectic composition under the same testing condition. However, our simulation results show that the electrical and thermal characteristics remain essentially almost the same during accelerated EM tests when the Pb-containing solders are replaced by Pb-free solders, suggesting that the melting points of the solders are likely the dominant factor in determining EM lifetimes. The EM behavior in Pb-free solder is a complicated phenomenon as multiple driving forces coexist in the joints and each joint contains more than four elements with distinct susceptibility to each driving force. Therefore, atomic transport due to electrical and thermal driving forces during EM is also investigated. In addition, several approaches are presented to reduce undesirable current crowding and Joule heating effects to improve EM resistance.

主出版物標題Lead-Free Electronic Solders
主出版物子標題A Special Issue of the Journal of Materials Science: Materials in Electronics
發行者Springer US
ISBN(列印)0387484310, 9780387484310
出版狀態Published - 1 十二月 2007

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