Coupling effect of thermomigration and cross-interaction on evolution of intermetallic compounds in Cu/Sn/Ni ultrafine interconnects undergoing TLP bonding


By reflowing Cu/Sn/Ni ultrafine interconnects under a temperature gradient, a new transient liquid phase (TLP) bonding process was proposed for three-dimensional packaging applications. The evolution of the dominant (Cu,Ni)6Sn5 intermetallic compounds depends strongly on the temperature gradient. The essential cause of such dependence is attributed to the different amounts of Cu and Ni atomic fluxes being introduced into the liquid solder. Under the coupling effect of thermomigration and Cu–Ni cross-interaction, the total atomic flux of Cu and Ni is promoted. As a result, the growth of dense (Cu,Ni)6Sn5 is significantly accelerated and the formation of Cu3Sn is eliminated. The new TLP bonding process consumes only a limited amount of the Ni substrate, but much more from the Cu substrate. The mechanism for the new TLP bonding process is discussed and experimentally verified in this study.

This is a preview of subscription content, access via your institution.

We’re sorry, something doesn't seem to be working properly.

Please try refreshing the page. If that doesn't work, please contact support so we can address the problem.

FIG. 1.
FIG. 2.
FIG. 3.
FIG. 4.
FIG. 5.
FIG. 6.
FIG. 7.


  1. 1.

    A. Munding, H. Hübner, A. Kaiser, S. Penka, P. Benkart, and E. Kohn: Cu/Sn solid-liquid interdiffusion bonding. In Wafer Level 3-D ICs Process Technology, C.S. Tang, R.J. Gutmann, and L.R. Reif eds. (Springer, New York, USA, 2008); pp. 131–169.

    Google Scholar 

  2. 2.

    G. Humpston and D.M. Jacobson: Principles of Soldering (ASM International, Materials Park, USA, 2004).

    Google Scholar 

  3. 3.

    G.O. Cook and C.D. Sorensen: Overview of transient liquid phase and partial transient liquid phase bonding. J. Mater. Sci. 46, 5305–5323 (2011).

    CAS  Article  Google Scholar 

  4. 4.

    N.S. Bosco and F.W. Zok: Critical interlayer thickness for transient liquid phase bonding in the Cu–Sn system. Acta Mater. 52, 2965–2972 (2004).

    CAS  Article  Google Scholar 

  5. 5.

    J.F. Li, P.A. Agyakwa, and C.M. Johnson: Kinetics of Ag3Sn growth in Ag–Sn–Ag system during transient liquid phase soldering process. Acta Mater. 58, 3429–3443 (2010).

    CAS  Article  Google Scholar 

  6. 6.

    N. Quitoriano, W.S. Wong, L. Tsakalakos, Y. Cho, and T. Sands: Kinetics of the Pd/In thin-film bilayer reaction: Implications for transient-liquid-phase wafer bonding. J. Electron. Mater. 30, 1471–1475 (2001).

    CAS  Article  Google Scholar 

  7. 7.

    T. Studnitzky and R. Schmid-Fetzer: Phase formation and diffusion soldering in Pt/In, Pd/In, and Zr/Sn thin-film systems. J. Electron. Mater. 32, 70–80 (2003).

    CAS  Article  Google Scholar 

  8. 8.

    S.W. Yoon, M.D. Glover, and K. Shiozaki: Nickel-tin transient liquid phase bonding toward high-temperature operational power electronics in electrified vehicles. IEEE Trans. Power Electron. 28, 2448–2456 (2013).

    Article  Google Scholar 

  9. 9.

    J.F. Li, P.A. Agyakwa, and C.M. Johnson: Interfacial reaction in Cu/Sn/Cu system during the transient liquid phase soldering process. Acta Mater. 59, 1198–1211 (2011).

    CAS  Article  Google Scholar 

  10. 10.

    M.L. Huang, C.M.L. Wu, J.K.L. Lai, and Y.C. Chan: Microstructural evolution of alead-free solder alloy Sn–Bi–Ag–Cu prepared by mechanical alloying during thermal shock and aging. J. Electron. Mater. 29, 1021–1026 (2000).

    CAS  Article  Google Scholar 

  11. 11.

    C.E. Ho, S.C. Yang, and C.R. Kao: Interfacial reaction issues for lead-free electronic solders. J. Mater. Sci.: Mater. Electron. 18, 155–174 (2007).

    CAS  Google Scholar 

  12. 12.

    S.J. Wang and C.Y. Liu: Kinetic analysis of the interfacial reactions in Ni/Sn/Cu sandwich structures. J. Electron. Mater. 35, 1955–1960 (2006).

    CAS  Article  Google Scholar 

  13. 13.

    Y.S. Huang, H.Y. Hsiao, C. Chen, and K.N. Tu: The effect of a concentration gradient on interfacial reactions in microbumps of Ni/SnAg/Cu during liquid-state soldering. Scr. Mater. 66, 741–744 (2012).

    CAS  Article  Google Scholar 

  14. 14.

    H.Y. Hsiao, C.M. Liu, H.W. Lin, T.C. Liu, C.L. Lu, Y.S. Huang, C. Chen, and K.N. Tu: Unidirectional growth of microbumps on (111)-oriented and nanotwinned copper. Science 336, 1007–1010 (2012).

    CAS  Article  Google Scholar 

  15. 15.

    C. Chen, H.Y. Hsiao, Y.W. Chang, F.Y. Ouyang, and K.N. Tu: Thermomigration in solder joints. Mater. Sci. Eng., R 73, 85–100 (2012).

    Article  Google Scholar 

  16. 16.

    Y.S. Yang, C.J. Yang, and F.Y. Ouyang: Interfacial reaction of Ni3Sn4 intermetallic compound in Ni/SnAg solder/Ni system under thermomigration. J. Alloys Compd. 674, 331–340 (2016).

    CAS  Article  Google Scholar 

  17. 17.

    M.Y. Guo, C.K. Lin, C. Chen, and K.N. Tu: Asymmetrical growth of Cu6Sn5 intermetallic compounds due to rapid thermomigration of Cu in molten SnAg solder joints. Intermetallics 29, 155–158 (2012).

    CAS  Article  Google Scholar 

  18. 18.

    N. Zhao, Y. Zhong, M.L. Huang, H.T. Ma, and W. Dong: Growth kinetics of Cu6Sn5 intermetallic compound at liquid-solid interfaces in Cu/Sn/Cu joints under temperature gradient. Sci. Rep. 5, 13491 (2015).

    CAS  Article  Google Scholar 

  19. 19.

    Y. Zhong, M.L. Huang, H.T. Ma, W. Dong, Y.P. Wang, and N. Zhao: In situ study on Cu–Ni cross-interaction in Cu/Sn/Ni solder joints under temperature gradient. J. Mater. Res. 31, 609–617 (2016).

    CAS  Article  Google Scholar 

  20. 20.

    N. Zhao, Y. Zhong, M.L. Huang, H.T. Ma, and W. Dong: Dissolution and precipitation kinetics of Cu6Sn5 intermetallics in Cu/Sn/Cu micro interconnects under temperature gradient. Intermetallics 79, 28–34 (2016).

    CAS  Article  Google Scholar 

  21. 21.

    F.P. Incropera and D.P. DeWitt: Fundamentals of Heat and Mass Transfer (Wiley, New York, USA, 2001).

    Google Scholar 

  22. 22.

    M.V. Peralta-Martinez and W.A. Wakeham: Thermal conductivity of liquid tin and indium. Int. J. Thermophys. 22, 395–403 (2001).

    CAS  Article  Google Scholar 

  23. 23.

    J.Y. Tsai, Y.C. Hu, C.M. Tsai, and C.R. Kao: A study on the reaction between Cu and Sn3.5Ag solder doped with small amounts of Ni. J. Electron. Mater. 32, 1203–1208 (2003).

    CAS  Article  Google Scholar 

  24. 24.

    V.I. Dybkov: Growth Kinetics of Chemical Compound Layers (Cambridge International Science Publishing, Cambridge, U.K., 1998).

    Google Scholar 

  25. 25.

    K. Nogita, D. Mu, S.D. McDonald, J. Read, and Y.Q. Wu: Effect of Ni on phase stability and thermal expansion of Cu6−xNixSn5 (X = 0, 0.5, 1, 1.5 and 2). Intermetallics 26, 78–85 (2012).

    CAS  Article  Google Scholar 

  26. 26.

    D. Mu, J. Read, Y. Yang, and K. Nogita: Thermal expansion of Cu6Sn5 and (Cu,Ni)6Sn5. J. Mater. Res. 26, 2660–2664 (2011).

    CAS  Article  Google Scholar 

Download references


This work was supported by the National Natural Science Foundation of China (Grant Nos. 51675080 and 51571049), the Key Laboratory of Advanced Display and System Applications (Shanghai University) (Grant No. P201601), and the Ministry of Education and the China Scholarship Council (Grant No. 201606065047).

Author information



Corresponding authors

Correspondence to Ning Zhao or Haitao Ma.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Zhong, Y., Zhao, N., Dong, W. et al. Coupling effect of thermomigration and cross-interaction on evolution of intermetallic compounds in Cu/Sn/Ni ultrafine interconnects undergoing TLP bonding. Journal of Materials Research 32, 3128–3136 (2017).

Download citation