A Model for Rapid Tin Whisker Growth on the Surface of ErSn3 Phase

作者:Hao, Hu*; Xu, Guangchen; Song, Yonglun; Shi, Yaowu; Guo, Fu
来源:Journal of Electronic Materials, 2012, 41(2): 184-189.
DOI:10.1007/s11664-011-1820-9

摘要

Spontaneous growth of tin whiskers on the finish of leadframes is an extremely slow process under moderate temperature conditions. It therefore becomes difficult to track the continuous growth of tin whiskers and to vary the experimental conditions to determine their root causes. Accordingly, the fundamental growth behaviors of tin whiskers are still not fully understood. In this study, rapid tin whisker growth was achieved by adding 1 wt.% Er to Sn-3.8Ag-0.7Cu solder alloy. The results showed unique tin whisker morphology with nonconstant cross-section. An explanation is proposed by adding kinetic energy to the conventional energy balance equation. In addition, a double compressive stress zone is proposed to demonstrate the driving force for tin whisker growth in rare-earth-bearing phases.

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