Abstract
Time-lapse SEM studies of Sn whiskers were conducted to estimate growth kinetics and document whisker morphologies. For straight whiskers, growth rates of 3 to 4 microns per day were measured at room temperature. Two types of kinked whiskers were observed. For Type A kinks, the original growth segment spatial orientation remains unchanged, there are no other changes in morphology or diameter, and growth continues. For Type B kinks, the spatial orientation of the original segment changes and it appears that the whisker bends over. Whiskers with Type B kinks show changes in morphology and diameter at the base, indicating grain boundary motion in the film, which eliminates the conditions suitable for long-term whisker growth. To estimate the errors in the whisker growth measurements, a technique is presented to correct for SEM projection effects. With this technique, the actual growth angles and lengths of a large number of whiskers were collected. It was found that most whiskers grow at moderate or shallow angles with respect to the surface; few straight whiskers grow nearly normal to the surface. In addition, there is no simple correlation between growth angles and lengths for whiskers observed over an approximate 2-year period.
Similar content being viewed by others
References
NASA Goddard Space Flight Center Tin Whisker Homepage, website http://nepp.nasa.gov/whisker/.
D.F. Susan, J.R. Michael, R.P. Grant, and W.G. Yelton: Microsc. Microanal., 2010, vol. 16, Suppl. 2, pp. 792–93.
J.R. Michael, B.B. McKenzie, and D.F. Susan: Microsc. Microanal., 2011, vol. 17, Suppl. 2, pp. 392–93.
N. Jadhav, E. Buchovecky, E. Chason, and A. Bower: JOM, 2010, vol. 62, pp. 30–37.
K.N. Tu and J.C.M. Li: Mater. Sci. Eng. A, 2005, vol. A409, pp. 131–39.
L. Reinbold, N. Jadhav, E. Chason, and K.S. Kumar: J. Mater. Res., 2009, vol. 24, pp. 3583–89.
G.S. Baker: Acta Met., 1957, vol. 5, pp. 353–57.
N. Furuta: Jpn. J. Appl. Phys., 1965, vol. 4, pp. 155–56.
P.W. Levy and O.F. Kammerer: J. Appl. Phys., 1955, vol. 26, pp. 1182–83.
J.B. Lebret and M.G. Norton: J. Mater. Res., 2003, vol. 18, pp. 585–93.
J.W. Osenbach, J.M. DeLucca, B.D. Potteiger, A. Amin, and F.A. Baiocchi: J. Mater. Sci: Mater. Electron, 2007, vol. 18, pp. 283–305.
B. Jiang and A.-P. Xian: Philos. Mag. Lett., 2006, vol. 86, pp. 521–27.
P. Sarobol, A.E. Pedigo, P. Su, J.E. Blendell, and C.A. Handwerker: IEEE Trans. Elect. Pack. Manuf., 2010, vol. 33, pp. 159–64.
W.J. Boettinger, C.E. Johnson, L.A. Bendersky, K.-W. Moon, M.E. Williams, and G.R. Stafford: Acta Mater., 2005, vol. 53, pp. 5033–50.
G.T. Galyon and L. Palmer: IEEE Trans. Elect. Pack. Manuf., 2005, vol. 28, pp. 17–30.
T. Frolov, W.J. Boettinger, and Y. Mishin: Acta Mater., 2010, vol. 58, pp. 5471–80.
B.-Z. Lee and D.N. Lee: Acta Mater., 1998, vol. 46, pp. 3701–14.
L. Panashchenko and M. Osterman: IEEE Elect. Comp. Tech. Conf., 2009, pp. 1037–43.
L. Panashchenko: M.S. Thesis, Univ. Maryland, 2009.
J.I. Goldstein, D.E. Newbury, P. Echlin, D.C. Joy, A.D. Romig, C.E. Lyman, C. Fiori, and E. Lifshin: Scanning Electron Microscopy and X-Ray Microanalysis, 2nd ed., Plenum Press, New York, 1992, pp. 260–267.
JESD22-A121A, JEDEC Standard No. 22-A121A, “A Test Method for Measuring Whisker Growth on Tin and Tin Alloy Surface Finishes”, 2008, JEDEC Solid State Technology Association.
S. Meschter, P. Snugovsky, J. Kennedy, S. McKeown, J. Keeping, and E. Kosiba: 5th Int. Symp. on Tin Whiskers, 2011, CALCE and Univ. of Maryland, College Park.
W.J.Choi, T.Y. Lee, K.N. Tu, N. Tamura, R.S. Celestre, A.A. MacDowell, Y.Y. Bong, and L. Nguyen: Acta Mater., 2003, vol. 51, pp. 6253–61.
P.T. Vianco and J.R. Rejent: J. Elect. Mater., 2009, vol. 38, pp. 1815–25.
P.T. Vianco and J.R. Rejent: J. Elect. Mater., 2009, vol. 38, pp. 1826–37.
E.J. Buchovecky, N. Du, and A.F. Bower: Appl. Phys. Lett., 2009, vol. 94, p. 191904.
M.S. Sellers, A.J. Schultz, C. Basaran, and D.A. Kofke: Phys. Rev. B, 2010, vol. 81, p. 134111.
Acknowledgments
Special thanks to Alice Kilgo and Lisa Deibler for laser confocal microscopy analysis. Jamin Pillars is acknowledged for Sn plating and Mark Reece for substrate preparation. Thanks also to Dr. C. V. Robino for an insightful review of the manuscript.
Author information
Authors and Affiliations
Corresponding author
Additional information
Manuscript submitted March 20, 2012.
Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy’s National Nuclear Security Administration.
Rights and permissions
About this article
Cite this article
Susan, D., Michael, J., Grant, R.P. et al. Morphology and Growth Kinetics of Straight and Kinked Tin Whiskers. Metall Mater Trans A 44, 1485–1496 (2013). https://doi.org/10.1007/s11661-012-1488-7
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11661-012-1488-7