Journal of Electronic Materials

, Volume 48, Issue 1, pp 9–16 | Cite as

Effects of Aspect Ratio on Microstructural Evolution of Ni/Sn/Ni Microjoints

  • T. H. Yang
  • H. Y. Yu
  • Y. W. Wang
  • C. R. KaoEmail author
TMS2018 Microelectronic Packaging, Interconnect, and Pb-free Solder
Part of the following topical collections:
  1. TMS2018 Advanced Microelectronic Packaging, Emerging Interconnection Technology, and Pb-free Solder


Under the simultaneous influence of volume shrinkage and surface solder diffusion, the microstructural evolution in Ni/Sn/Ni microjoints exhibits a conformable tendency among different joint sizes. This conformable tendency is the necking of the Sn layer and the initiation of voids which occur only near the periphery of the Sn layer. The reasons for this joint-size dependency have been theoretically evaluated and proposed in this study. This dependency remains applicable until the Ni3Sn4 layers growing in opposite directions impinge on each other. Afterward, microvoids are able to form everywhere along the centerline of the joints. It is hypothesized that the electrical and mechanical performance of microjoints is significantly related to the microstructures in these joints. With the help of the joint-size dependency proposed in this study, it is expected that the dimensional design of microjoints is capable of being optimized to assure high reliability.


Microjoints volume shrinkage surface diffusion interfacial reactions NiSn4 


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The authors are grateful to the financial support of the Ministry of Science and Technology of Taiwan through Grants 104-2221-E-002-040-MY3 and 104-2221-E-002-052-MY3.


  1. 1.
    H.Y. Chuang, T.L. Yang, M.S. Kuo, Y.J. Chen, J.J. Yu, C.C. Li, and C.R. Kao, I.E.E.E. Trans. Device Mater. Reliab. 12, 233 (2012).CrossRefGoogle Scholar
  2. 2.
    W.M. Haynes, CRC Handbook of Chemistry and Physics, 92nd ed. (New York, NY: CRC Press, 2012).Google Scholar
  3. 3.
    H.P.R. Frederikse, R.J. Fields, and A. Feldman, J. Appl. Phys. 72, 2879 (1992).CrossRefGoogle Scholar
  4. 4.
    H.Y. Chuang, J.J. Yu, M.S. Kuo, H.M. Tong, and C.R. Kao, Scr. Mater. 66, 171 (2012).CrossRefGoogle Scholar
  5. 5.
    W.M. Chen, T.L. Yang, C.K. Chung, and C.R. Kao, Scr. Mater. 65, 331 (2011).CrossRefGoogle Scholar
  6. 6.
    K. Kulojärvi, V. Vuorinen, and J. Kivilahti, Microelectron. Int. 15, 20 (1998).CrossRefGoogle Scholar
  7. 7.
    J.J. Yu, C.A. Yang, Y.F. Lin, C.H. Hsueh, and C.R. Kao, J. Alloys Compd. 629, 16 (2015).CrossRefGoogle Scholar
  8. 8.
    C.C. Li, C.K. Chung, W.L. Shih, and C.R. Kao, Metall. Mater. Trans. A 45, 2343 (2014).CrossRefGoogle Scholar
  9. 9.
    C.C. Li, J.H. Ke, C.A. Yang, and C.R. Kao, Mater. Lett. 156, 150 (2015).CrossRefGoogle Scholar
  10. 10.
    Y.S. Kaganovskii, L.N. Paritskaya, and W. Lojkowski, Surf. Sci. 454, 591 (2000).CrossRefGoogle Scholar
  11. 11.
    Y.S. Kaganovsky, L.N. Paritskaya, and V.V. Bogdanov, Defect. Diffus. Forum (2008).
  12. 12.
    Y. Kaganovskii, L.N. Paritskaya, V.V. Bogdanov, and A.O. Grengo, Acta Mater. 45, 3927 (1997).CrossRefGoogle Scholar
  13. 13.
    H.W. Yang, J.Y. Wu, Z.X. Zhu, and C.R. Kao, Mater. Chem. Phys. 191, 13 (2017).CrossRefGoogle Scholar
  14. 14.
    H.W. Yang, H.Y. Yu, and C.R. Kao, in Electronic Components and Technology Conference (ECTC) Proceeding (2017), pp. 1008–1013.Google Scholar
  15. 15.
    H.K. Cheng, Y.J. Lin, H.C. Chang, K.C. Liu, Y.L. Wang, T.F. Liu, and C.M. Chen, Metall. Mater. Trans. A 46, 1834 (2015).CrossRefGoogle Scholar
  16. 16.
    H.K. Cheng, Y.J. Lin, C.M. Chen, K.C. Liu, Y.L. Wang, and T.F. Liu, Metall. Mater. Trans. A 47, 3971 (2016).CrossRefGoogle Scholar
  17. 17.
    M.E. Glicksman, Diffusion in Solids: Field Theory, Solid-State Principles and Applications (New York, NY: Wiley, 2000), p. 79.Google Scholar
  18. 18.
    C.M. Chen and S.W. Chen, Acta Mater. 50, 2461 (2002).CrossRefGoogle Scholar
  19. 19.
    C.E. Ho, S.C. Yang, and C.R. Kao, J. Mater. Sci.: Mater. Electron. 18, 155 (2007).Google Scholar

Copyright information

© The Minerals, Metals & Materials Society 2018

Authors and Affiliations

  • T. H. Yang
    • 1
  • H. Y. Yu
    • 1
  • Y. W. Wang
    • 1
  • C. R. Kao
    • 1
    Email author
  1. 1.Department of Materials Science and EngineeringNational Taiwan UniversityTaipei CityTaiwan

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