Hostname: page-component-586b7cd67f-rdxmf Total loading time: 0 Render date: 2024-11-23T10:33:59.487Z Has data issue: false hasContentIssue false
  • English
  • Français

Electromigration induced microstructure and morphological changes in eutectic SnPb solder joints

Published online by Cambridge University Press:  31 January 2011

A. Lee ,
C.E. Ho  and
K.N. Subramanian
A. Lee*
Affiliation:
Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, Michigan 48824
C.E. Ho
Affiliation:
Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, Michigan 48824
K.N. Subramanian
Affiliation:
Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, Michigan 48824
*
a)Address all correspondence to this author. e-mail: [email protected]
Get access

Abstract

Simultaneous direct current stressing with thermal aging accelerates the migration of conducting species resulting in significant microstructural coarsening. Because of the synergistic fields influence, such coarsening begins from the anode and propagates toward the cathode. Prolonged current stressing with 104 A/cm2 at 150 °C causes the inter-lamellar eutectic SnPb to become a two-layer structure, with a Pb-rich layer adjacent to the anode and an Sn-rich layer adjacent to the cathode. This mass movement causes hillock/valley formation, and the extents of such surface undulations increase with increases in the time duration of current stressing as well as with the joint thickness. In thinner solder joints these events occur sooner, although the extents of surface undulations depend on the thickness of joints. In addition, Cu present in the substrate and in the intermetallic layer at the cathode migrates to form Cu6Sn5 within the Sn-rich layer, in a region close to the Pb-rich layer.

Keywords

ElectromigrationMicrostructurePackaging
Type
Articles
Information
Journal of Materials Research , Volume 22 , Issue 11 , November 2007 , pp. 3265 - 3272
Copyright
Copyright © Materials Research Society 2007

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1Tu, K.N.: Recent advances on electromigration in very-large-scale-integration of interconnects. J. Appl. Phys. 94, 5451 2003CrossRefGoogle Scholar
2Yeh, Y.T., Chou, C.K., Hsu, Y.C., Chen, C.Tu, K.N.: Threshold- current density of electrmigration in eutectic SnPb solder. Appl. Phys. Lett. 86, 203504 2005CrossRefGoogle Scholar
3Yeh, E.C.C., Choi, W.J., Tu, K.N., Elenius, P.Balkan, H.: Current crowding induced electromigration failure in flip chip solder joints. Appl. Phys. Lett. 80, 580 2002CrossRefGoogle Scholar
4Shao, T.L., Chiu, S.H., Chen, C., Yao, D.J.Hsu, C.Y.: Thermal gradient in solder joints under electrical-current stressing. J. Electron. Mater. 33, 1350 2004CrossRefGoogle Scholar
5Liu, Y.H.Lin, K.L.: Damages and microstructural variation of high-lead and eutectic Sn-Pb composite flip chip solder bumps induced by electromigration. J. Mater. Res. 20, 2184 2005CrossRefGoogle Scholar
6Tsai, C.M., Lin, Y.L., Tsai, J.Y., Lai, Y.S.Kao, C.R.: Local melting induced by electromigration in flip-chip solder joints. J. Electron. Mater. 35, 1005 2006CrossRefGoogle Scholar
7Lin, Y.L., Chang, C.W., Tsai, C.M., Lee, C.W.Kao, C.R.: Electromigration-induced UBM consumption and the resulting failure mechanisms in flip chip solder joints. J. Electron. Mater. 35, 1010 2006CrossRefGoogle Scholar
8Liang, S.W., Chang, Y.W., Chen, C., Liu, Y.C., Chen, K.H.Lin, S.H.: Geometrical effect of bump resistance measurement by Kelvin structure. J. Electron. Mater. 35, 1647 2006CrossRefGoogle Scholar
9Chiu, S.H., Shao, T.L., Chen, C., Yao, D.J.Hsu, C.Y.: Infrared microscopy of hot spots induced by Joule heating in flip-chip SnAg solder joints under accelerated electromigration. Appl. Phys. Lett. 88, 022110 2006CrossRefGoogle Scholar
10Nah, J.W., Suh, J.O., Tu, K.N., Yoon, S.W., Rao, V.S., Kripesh, V.Hua, F.: Electromigration in flip chip solder joints having a thick Cu column bump and a shallow solder interconnect. J. Appl. Phys. 100, 123513 2006CrossRefGoogle Scholar
11Ho, C.E., Lee, A.Subramanian, K.N.: Design of solder joints for fundamental studies on the effects of electromigration. J. Mater. Sci.: Mater. Electron. 18, 129 2007Google Scholar
12Rahn, A.: The Basics of Soldering John Wiely and Sons Press New York 1993Google Scholar
13Liu, C.Y., Chen, C., Liao, C.N.Tu, K.N.: Microstructure-electromigration correlation in a thin stripe of eutectic SnPb solder stressed between Cu electrodes. Appl. Phys. Lett. 75, 58 1999CrossRefGoogle Scholar
14Wei, C.C.Chen, C.: Critical length of electromigration for eutectic SnPb solder stripe. Appl. Phys. Lett. 88, 182105 2006CrossRefGoogle Scholar
15Huntington, H.B.: Electromigartion in metals in Diffusion in Solids: Recent Developments edited by A.S. Nowick and J.J. Burton Academic Press New York 1975Google Scholar
16Guo, F.: Composite lead-free electronic solders. J. Mater. Sci.: Mater. Electron. 18, 129 2007Google Scholar