Spontaneous Tin Whisker Growth: Mechanism and Prevention
Whisker growth on beta-tin (β-Sn) is a surface relief phenomenon of creep [1–16]. It is driven by a compressive stress gradient and occurs at room temperature. Spontaneous Sn whiskers are known to grow on matte Sn finish on Cu. Today, due to the wide application of Pb-free solders on Cu conductors used in the packaging of consumer electronic products, Sn whisker growth has become a serious reliability issue because the Sn-based Pb-free solders are very rich in Sn. The matrix of most Sn-based Pb-free solders is almost pure Sn. The well-known phenomena of tin such as tin-cry, tin-pest, and tin-whisker are receiving attention again.
KeywordsStress Gradient Whisker Growth Consumer Electronic Product Laue Pattern Deviatoric Strain Tensor
Unable to display preview. Download preview PDF.
- F. C. Frank, Philos. Mag., 44, 854 (1953).Google Scholar
- W. C. Ellis, D. F. Gibbons, and R. C. Treuting, “Growth of metal whiskers from the solid,” in “Growth and Perfection of Crystals,” R. H. Doremus, B. W. Roberts, and D. Turnbull (Eds.), John Wiley, New York, pp. 102–120 (1958).Google Scholar
- A. P. Levitt, in “Whisker Technology,” Wiley–Interscience, New York (1970).Google Scholar
- I. Amato, “Tin whiskers: The next Y2K problem?” Fortune magazine, vol. 151, issue 1, p.27 (2005).Google Scholar
- R. Spiegel, “Threat of tin whiskers haunts rush to lead-free,” Electronic News, 03/17/2005.Google Scholar
- W. J. Choi, G. Galyon, K. N. Tu, and T. Y. Lee, “The structure and kinetics of tin whisker formation and growth on high tin content finishes,” in “Handbook of Lead-Free Solder Technology for Microelectronic Assemblies,” K. J. Puttlitz and K. A. Stalter (Eds.), Marcel Dekker, New York (2004).Google Scholar
- P. G. Shewmon, “Diffusion in Solids,” McGraw–Hill, New York (1963).Google Scholar
- D. A Porter and K. E. Easterling, “Phase Transformations in Metals and Alloys,” Chapman & Hall, London (1992).Google Scholar
- K. Zeng, R. Stierman, T.-C. Chiu, D. Edwards, K. Ano, and K. N. Tu, “Kirkendall void formation in SnPb solder joints on bare Cu and its effect on joint reliability,” J. Appl. Phys., 97, 024508-1 to –8 (2005).Google Scholar