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.
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.
G. Humpston and D.M. Jacobson: Principles of Soldering (ASM International, Materials Park, USA, 2004).
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).
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).
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).
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).
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).
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).
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).
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).
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).
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).
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).
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).
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).
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).
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).
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).
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).
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).
F.P. Incropera and D.P. DeWitt: Fundamentals of Heat and Mass Transfer (Wiley, New York, USA, 2001).
M.V. Peralta-Martinez and W.A. Wakeham: Thermal conductivity of liquid tin and indium. Int. J. Thermophys. 22, 395–403 (2001).
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).
V.I. Dybkov: Growth Kinetics of Chemical Compound Layers (Cambridge International Science Publishing, Cambridge, U.K., 1998).
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).
D. Mu, J. Read, Y. Yang, and K. Nogita: Thermal expansion of Cu6Sn5 and (Cu,Ni)6Sn5. J. Mater. Res. 26, 2660–2664 (2011).
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).
About this article
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). https://doi.org/10.1557/jmr.2017.171