Mitigation of Long Whisker Growth Based upon the Dynamic Recrystallization Mechanism

  • P. T. ViancoEmail author
  • D. P. Cummings
  • P. G. Kotula
  • B. M. McKenzie
  • L. M. Lowery
  • S. Williams
  • D. Banga


The role of an Fe layer under a Sn layer to mitigate long whisker formation by the Fe/Sn interface through modification of the driving force for dynamic recrystallization (DRX) has been studied using a laboratory test vehicle with a Si (wafer) base material and evaporated layers of Cr (adhesion layer), Fe, and Sn. The latter two layers had thickness combinations of 10 nm Fe/0.5 μm Sn and 40 nm Fe/2.0 μm Sn. Aging was carried out for 9 days at temperature of 25°C, 60°C, and 100°C under stress conditions. Applied loads of 0 g or 500 g compression did not affect the results. Industrial test vehicles including electroplated layers of Sn and Fe (0.5 μm to 2.0 μm) were subjected to the same aging treatments. The absence of long whiskers and hillocks from the laboratory test vehicles indicated that the Fe/Sn interface altered the driving force of DRX rather than altering grain boundary mobility. The presence of depleted zones confirmed that the Fe layer did not affect the long-range diffusion. The industrial test samples showed that the Fe/Sn interface prevented the formation of long whiskers on the electroplated Sn films for similar aging conditions. The Fe layer provided a suitable barrier against Cu diffusion into the Sn layer. Copper in the Sn layer, even when only in solid solution, enhanced the DRX driving force for whisker growth.


Tin whiskers Fe layer dynamic recrystallization mitigation 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.



The authors wish to thank Don Susan for a thorough review of the manuscript. Sandia National Laboratories is a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia LLC, a wholly owned subsidiary of Honeywell International Inc. for the US Department of Energy’s National Nuclear Security Administration under Contract DE-NA0003525. This paper describes objective technical results and analysis. Any subjective views or opinions that might be expressed in the paper do not necessarily represent the views of the US Department of Energy or the US Government.


  1. 1.
    P. Vianco and J. Rejent, J. Electron. Mater. 38, 1815 (2009).CrossRefGoogle Scholar
  2. 2.
    P. Vianco and J. Rejent, J. Electron. Mater. 38, 1826 (2009).CrossRefGoogle Scholar
  3. 3.
    P. Vianco, M. Neilsen, J. Rejent, and R. Grant, J. Electron. Mater. 44, 4012 (2015).CrossRefGoogle Scholar
  4. 4.
    D.-K. Kim, W. Nix, R. Vinci, M. Deal, and J. Plummer, J. Appl. Phys. 90, 781 (2001).CrossRefGoogle Scholar
  5. 5.
    I. Petrov, P. Barna, L. Hultman, and J. Greene, J. Vac. Sci. Technol. A 21, s117 (2003).CrossRefGoogle Scholar
  6. 6.
    F. d’Huerle, Thin Solid Films 12, 399 (1972).CrossRefGoogle Scholar
  7. 7.
    P. Chaudhari, J. Vac. Sci. Technol. 9, 520 (1972).CrossRefGoogle Scholar
  8. 8.
    F. Genin, J. Appl. Phys. 77, 5130 (1995).CrossRefGoogle Scholar
  9. 9.
    W. Nix, Metall. Trans. A 20A, 2217 (1989).CrossRefGoogle Scholar
  10. 10.
    C. Thompson, Annu. Rev. Mater. Sci. 20, 245 (1990).CrossRefGoogle Scholar
  11. 11.
    C. Thompson and R. Carel, J. Mech. Phys. Solids 44, 657 (1996).CrossRefGoogle Scholar
  12. 12.
    U. Smith, J. Vac. Sci. Technol. 9, 2527 (1991).CrossRefGoogle Scholar
  13. 13.
    Y. Hou and C.M. Tan, Semicond. Sci. Technol. (2008). Scholar
  14. 14.
    F. d’Heurle, Int. Mater. Rev. 34, 53 (1989).CrossRefGoogle Scholar
  15. 15.
    J. Nielsen and T. Woodrow, Final Report: SERDP Project WP-1751 (Strategic Research and Development Program, Alexandria, 2013)Google Scholar
  16. 16.
    R. Kawanaka, K. Fujiwara, S. Nango, and T. Hasegawa, Jpn. J. Appl. Phys. 22, 917 (1983).CrossRefGoogle Scholar
  17. 17.
    C. Chang and R. Vook, Thin Solid Films 228, 205 (1993).CrossRefGoogle Scholar
  18. 18.
    J. Smetana, IEEE Trans. Comput. Packag. Manuf. Technol. 30, 11 (2007).Google Scholar
  19. 19.
    P. Jagtap, A. Chakraborty, P. Eisenlohr, and P. Kumar, Acta Mater. 134, 346 (2017).CrossRefGoogle Scholar
  20. 20.
    A. Etienne, E. Cadel, A. Lina, L. Cretinon, and P. Pareige, IEEE Trans. Comput. Packag. Manuf. Technol. 2, 1928 (2012).CrossRefGoogle Scholar
  21. 21.
    P. Jagtap, V. Sethuraman, and P. Kumar, J. Electron. Mater. 47, 5229 (2018).CrossRefGoogle Scholar
  22. 22.
    E. Chason and F. Pei, J. Met. 67, 2416 (2015).Google Scholar
  23. 23.
    Linear Thermal Expansion Coefficient for Metals (2018).
  24. 24.
    T. Massalski, J. Murray, L. Bennett, and H. Baker (eds.), Binary Alloy Phase Diagrams (ASM International, Materials Park, OH, 1986) p. 944Google Scholar
  25. 25.
    T. Massalski, J. Murray, L. Bennett, and H. Baker (eds.), Binary Alloy Phase Diagrams (ASM International, Materials Park, OH, 1986), p. 1861Google Scholar
  26. 26.
    G. Pantazopoulos and A. Vazdirvanidis, Microscopy and Analysis, p. 13 (2008)Google Scholar
  27. 27.
    J. Wilson, Philos. Mag. 27, 1467 (1973).CrossRefGoogle Scholar
  28. 28.
    J. Cheng, P. Vianco, and J. Li, J. Appl. Phys. (2010). Scholar
  29. 29.
    P. Vianco and M. Neilsen, Office of Scientific and Technical Information, 1427292 (U.S. Government, Washington, DC, 2015)Google Scholar
  30. 30.
    Y. Zhang, C. Xu, J. Abys, and A. Vysotskaya, Report to the IPC SMEMA Council (IPC, Bannockburn, IL, 2002)Google Scholar
  31. 31.
    Y. Wang, D. Ding, T. Liu, K.-P. Galuschki, Y. Hu, A. Gong, Ming Shen, H. Sun, X. Wang, J. Sun, M. Li, and D. Mao, in Proceedings of the 11th International Conference on Electronic Packaging Technology and High Density Package, pp. 980–983 (2010)Google Scholar
  32. 32.
    M. Osterman, in Report to the CALCE EPSC Working Group (CALCE, University of Maryland, 2002)Google Scholar
  33. 33.
    P. Vianco and J. Rejent, Low Thermal Expansion Alloys and Composites, ed. J. Stephens and D. Frear (Warrendale: TMS, 1992), p. 147.Google Scholar
  34. 34.
    G. Panzeri, A. Accogli, E. Gibertini, C. Rinaldi, L. Nobili, and L. Magagnin, Electrochim. Acta 271, 576 (2018).CrossRefGoogle Scholar

Copyright information

© The Minerals, Metals & Materials Society 2019

Authors and Affiliations

  • P. T. Vianco
    • 1
    Email author
  • D. P. Cummings
    • 1
  • P. G. Kotula
    • 1
  • B. M. McKenzie
    • 1
  • L. M. Lowery
    • 1
  • S. Williams
    • 1
  • D. Banga
    • 2
  1. 1.Sandia National LaboratoriesAlbuquerqueUSA
  2. 2.Sandia National LaboratoriesLivermoreUSA

Personalised recommendations