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Ripening-assisted void formation in the matrix of lead-free solder joints during solid-state aging

Published online by Cambridge University Press:  03 March 2011

J.W. Jang ,
J.K. Lin ,
D.R. Frear ,
T.Y. Lee  and
K.N. Tu
J.W. Jang*
Affiliation:
Freescale Semiconductor, Inc., Tempe, Arizona 85284
J.K. Lin
Affiliation:
Freescale Semiconductor, Inc., Tempe, Arizona 85284
D.R. Frear
Affiliation:
Freescale Semiconductor, Inc., Tempe, Arizona 85284
T.Y. Lee
Affiliation:
Department of Materials Engineering, Hanbat National University, Daejeon, Republic of Korea
K.N. Tu
Affiliation:
Department of Materials Science and Engineering, University of California–Los Angeles, Los Angeles, California 90095-1595
*
a) Address all correspondence to this author. e-mail: [email protected]
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Abstract

Void formation in lead-free solder joints, away from the joint interface, has been observed after solid-state aging. These voids are attached to intermetallic precipitates in the solder matrix, especially to those that are adjacent to the layered intermetallic at the joint interface. Two potential void formation mechanisms are discussed. The mechanism proposed to describe void formation is that a flux of vacancies is created due to volume contraction during solid-state reaction. The ripening process among the intermetallics also assists this process. Using the suggested mechanisms, the void size was estimated. This phenomenon differs from the classical Kirkendall void formation because it is a nonequilibrium state of void formation and stress generation.

Keywords

DiffusionPackagingSoldering
Type
Rapid Communications
Information
Journal of Materials Research , Volume 22 , Issue 4 , April 2007 , pp. 826 - 830
Copyright
Copyright © Materials Research Society 2007

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References

REFERENCES

1Vianco, P.T. and Frear, D.R.: Issues in the replacement of lead-bearing solders. JOM 93, 14 (1993).CrossRefGoogle Scholar
2Glazer, J.: Metallurgy of low temperature Pb-free solders for electronic assembly. Int. Mater. Rev. 40, 65 (1995).CrossRefGoogle Scholar
3Kim, H.K., Liou, H.K., and Tu, K.N.: Morphology of instability of the wetting tips of eutectic SnBi, eutectic SnPb, and pure Sn on Cu. J. Mater. Res. 10, 497 (1995).CrossRefGoogle Scholar
4Powers, T.A., Singler, T.J., and Clum, J.A.: Role of tin content in the wetting of Cu and Au by tin–bismuth solders. J. Electron. Mater. 23, 773 (1994).CrossRefGoogle Scholar
5Jang, J.W., Frear, D.R., Lee, T.Y., and Tu, K.N.: Morphology of interfacial reaction between lead-free solders and electroless Ni-P under bump metallization. J. Appl. Phys. 88, 8359 (2000).CrossRefGoogle Scholar
6Vianco, P.T., Erickson, K.L., and Hopkins, P.L.: Solid state intermetallic compound growth between copper and high temperature, tin-rich solders. I. Experimental analysis. J. Electron. Mater. 23, 721 (1994).CrossRefGoogle Scholar
7Vianco, P.T., Hilva, P.F., and Kilgo, A.C.: Intermetallic compound layer formation between copper and hot-dipped 100In, 50In–50Sn, 100Sn, and 63Sn–37Pb coatings. J. Electron. Mater. 23, 583 (1994).CrossRefGoogle Scholar
8Flanders, D.R., Jacobs, E.G., and Pinizzotto, R.F.: Activation energies of intermetallic growth of Sn–Ag eutectic solder on copper substrates. J. Electron. Mater. 26, 883 (1997).CrossRefGoogle Scholar
9Minor, A.M. and Morris, J.W.: Inhibiting growth of the Au0.5Ni0.5Sn4 intermetallic layer in Pb–Sn solder joints reflowed on Au/Ni metallization. J. Electron. Mater. 29, 1170 (2000).CrossRefGoogle Scholar
10Lee, K.Y., Li, M., and Tu, K.N.: Growth and ripening of (Au,Ni)Sn4 phase in Pb-free and Pb-containing solders on Ni/Au metallization. J. Mater. Res. 18, 2562 (2003).CrossRefGoogle Scholar
11Deng, X., Sidhu, R.S., Johnson, P., and Chawla, N.: Influence of reflow and thermal aging on the shear strength and fracture behavior of Sn–3.5Ag solder/Cu joints. Metall. Mater. Trans. A 36A, 55 (2005).CrossRefGoogle Scholar
12Shin, M.S. and Kim, Y.H.: Microstructure characterization of Sn–Ag solder joints between stud bumps and metal pads. J. Electron. Mater. 32, 1448 (2003).CrossRefGoogle Scholar
13Nurmi, S.T., Sundelin, J.J., Ristolainen, E.O., and Lepisto, T.: The influence of multiple reflow cycles on solder joint voids for lead-free PBGAs. Solder. Surf. Mount Technol. 15, 31 (2003).CrossRefGoogle Scholar
14Tu, K.N.: Irreversible processes of spontaneous whisker growth in bimetallic Cu–Sn thin-film reactions. Phys. Rev. B49, 2030 (1994).CrossRefGoogle Scholar
15Gusak, A.M., Lutsenko, G.V., and Tu, K.N.: Ostwald ripening with non-equilibrium vacancies. Acta Mater. 54, 785 (2006).CrossRefGoogle Scholar
16Tu, K.N.: Interdiffusion and reaction in bimetallic Cu–Sn thin films. Acta Metall. 21, 347 (1973).CrossRefGoogle Scholar
17Lee, B.Z. and Lee, D.N.: Spontaneous growth mechanism of tin whiskers. Acta Mater. 46, 3701 (1998).CrossRefGoogle Scholar
18Tu, K.N., Mayer, J.W., and Feldman, L.C.: Electronic Thin Film Science (Macmillan Co., New York, 1992), Chap. 4.Google Scholar