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Effects of electromigration on interfacial reactions in cast Sn/Cu joints

Published online by Cambridge University Press:  03 March 2011

Sinn-Wen Chen*
Affiliation:
Department of Chemical Engineering, National Tsing Hua University, Hsin-chu, Taiwan
Chao-Hong Wang
Affiliation:
Department of Chemical Engineering, National Tsing Hua University, Hsin-chu, Taiwan
*
a) Address all correspondence to this author. e-mail: swchen@che.nthu.edu.tw
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Abstract

The Sn/Cu/Sn/Cu/Sn sandwich-type couples prepared by the casting method are used for examining the effects of electromigration on Sn/Cu interfacial reactions. The samples are reacted at 170 and 180 °C for 24–240 h by passing an electric current with a density of 5000 A/cm2. At the interfaces where electrons flow from the Sn side to the Cu side, uniform layers of Cu6Sn5 and Cu3Sn are formed. The results are similar to those without passage of an electric current. The relatively thicker Cu6Sn5 layer is attributed to the extra Cu source from the dissolved Cu during the sample preparation. At the interfaces where electrons flow from the Cu side to the Sn side, large and nonplanar Cu6Sn5 phase regions are formed. Formation of large Cu6Sn5 regions is the result of electromigration-enhanced Cu diffusion through the grain boundaries and surfaces.

Type
Articles
Copyright
Copyright © Materials Research Society 2007

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References

REFERENCES

1Görlich, J., Schmitz, G., and Tu, K.N.: On the mechanism of the binary Cu/Sn solder reaction. Appl. Phys. Lett. 86, 053106 (2005).CrossRefGoogle Scholar
2Gagliano, R.A. and Fine, M.E.: Thickening kinetics of interfacial Cu6Sn5 and Cu3Sn layers during reaction of liquid tin with solid copper. J. Electron. Mater. 32, 1441 (2003).CrossRefGoogle Scholar
3Chen, S-W. and Yen, Y-W.: Interfacial reactions in Ag-Sn/Cu couples. J. Electron. Mater. 28, 1203 (1999).CrossRefGoogle Scholar
4Su, L-H., Yen, Y-W., and Chen, S-W.: Interfacial reactions in the molten Sn/Cu and molten In/Cu couples. Metall. Mater. Trans. B 28B, 927 (1997).CrossRefGoogle Scholar
5Tu, K.N., Gusak, A.M., and Li, M.: Physics and materials challenges for lead-free solders. J. Appl. Phys. 93, 1335 (2003).CrossRefGoogle Scholar
6Sharif, A. and Chan, Y.C.: Comparative study of interfacial reactions of Sn-Ag-Cu and Sn-Ag solders on Cu pads during reflow soldering. J. Electron. Mater. 34, 46 (2005).CrossRefGoogle Scholar
7Chen, S-W., Chen, C-M., and Liu, W-C.: Electric current effects upon the Sn/Cu and Sn/Ni interfacial reactions. J. Electron. Mater. 27, 1193 (1998).CrossRefGoogle Scholar
8Gan, H. and Tu, K.N.: Polarity effect of electromigration on kinetics of intermetallic compound formation in Pb-free solder V-groove samples. J. Appl. Phys. 97, 063514 (2005).CrossRefGoogle Scholar
9Hu, Y.C., Lin, Y.H., Kao, C.R., and Tu, K.N.: Electromigration failure in flip chip solder joints due to rapid dissolution of copper. J. Mater. Res. 18, 2544 (2003).CrossRefGoogle Scholar
10Hsu, Y.C., Chen, D.C., Liu, P.C., and Chen, C.: Measurement of electromigration parameters of lead-free SnAg3.5 solder using U-groove lines. J. Mater. Res. 20, 2831 (2005).CrossRefGoogle Scholar
11Chen, C-M. and Chen, S-W.: Electromigration effect upon the Sn-0.7 wt%Cu/Ni and Sn-3.5 wt%Ag/Ni interfacial reactions. J. Appl. Phys. 90, 1208 (2001).CrossRefGoogle Scholar
12Chen, C-M. and Chen, S-W.: Effect upon the Sn/Ag and Sn/Ni interfacial reactions at various temperatures. Acta Mater. 50, 2461 (2002).CrossRefGoogle Scholar
13Nah, J.W., Suh, J.O., and Tu, K.N.: Effect of current crowding and Joule heating on electromigration induced failure in flip chip composite solder joints tested at room temperature. J. Appl. Phys. 98, 013715 (2005).CrossRefGoogle Scholar
14Ye, H., Basaran, C., and Hopkins, D.: Thermomigration in Pb-Sn solder joints under Joule heating during electric current stressing. Appl. Phys. Lett. 82, 1045 (2003).CrossRefGoogle Scholar
15Van Loo, F.J.J.: Multiphase diffusion in binary and ternary solid-state systems. Prog. Solid State Chem. 20, 47 (1990).CrossRefGoogle Scholar
16Choi, W.J., Yen, E.C.C., and Tu, K.N.: Mean-time-to-failure study of flip chip solder joints on Cu/Ni(V)/Al thin-film under-bump-metallization. J. Appl. Phys. 94, 5665 (2003).CrossRefGoogle Scholar
17Huang, M.L., Loeher, T., Ostmann, A., and Reichl, H.: Role of Cu in dissolution kinetics of Cu metallization in molten Sn-based solders. Appl. Phys. Lett. 86, 181908 (2005).CrossRefGoogle Scholar
18Sheng, G.T.T., Hu, C.F., Choi, W.J., Tu, K.N., Bong, Y.Y., and Nguyen, L.: Tin whiskers studied by focused ion beam imaging and transmission electron microscopy. J. Appl. Phys. 92, 64 (2002).CrossRefGoogle Scholar