標題: Relieving Sn whisker growth driven by oxidation on Cu leadframe by annealing and reflowing treatments
作者: Wei, C. C.
Liu, P. C.
Chen, Chih
Lee, Jeffrey C. B.
Wang, I. Ping
材料科學與工程學系
Department of Materials Science and Engineering
公開日期: 15-Aug-2007
摘要: Owing to environmental concern, Pb-free solders are replacing eutectic tin lead in electronic packaging industry. Thus, whisker growth becomes a serious reliability issue for Sn finishes. In this study, the mechanism of whisker growth from Sn finish on Cu leadframe was investigated under the temperature/humidity storage test. It is found that oxidation of the Sn finish was the driving force behind the whisker growth. Thermal treatments including annealing at 220 degrees C and reflowing at 260 degrees C were employed to mitigate the whisker growth. It is found that both heat treatments can significantly reduce the whisker growth rate. It is speculated that the heat treatments can relieve the residual stress in the Sn finishes and can modify their grain structure, resulting in a slower oxidation rate. Thus, they can slow down the grow rate of Sn whiskers. In addition, reflowing treatment can change the columnar grain structure of the Sn film to the equiaxed grain structure in some of its regions, resulting in a lower grain boundary diffusion rate of Sn. Therefore, the reflowed sample had the lowest growth rate of Sn whiskers. (c) 2007 American Institute of Physics.
URI: http://dx.doi.org/10.1063/1.2770832
http://hdl.handle.net/11536/10443
ISSN: 0021-8979
DOI: 10.1063/1.2770832
期刊: JOURNAL OF APPLIED PHYSICS
Volume: 102
Issue: 4
結束頁: 
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