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Journal of Materials Science

, Volume 49, Issue 4, pp 1755–1763 | Cite as

Reverse polarity effect and cross-solder interaction in Cu/Sn–9Zn/Ni interconnect during liquid–solid electromigration

  • M. L. Huang
  • Q. Zhou
  • N. Zhao
  • X. Y. Liu
  • Z. J. Zhang
Article

Abstract

The diffusion behavior of Zn atoms and Cu–Ni cross-solder interaction in Cu/Sn–9Zn/Ni interconnects during liquid–solid electromigration were investigated under a current density of 5.0 × 103 A/cm2 at 230 °C. Under the combined effect of chemical potential gradient and electron wind, Zn atoms with positive effective charge number would directionally diffuse toward the Cu interface under both flowing directions of electrons. When electrons flowed from Cu substrate to Ni substrate, EM significantly enhanced the diffusion of Cu atoms to the opposite Ni interface, resulting in the formation of interfacial Cu5Zn8; while no Ni atoms diffused to the opposite Cu interface. When electrons flowed from Ni substrate to Cu substrate, only a small amount of Cu atoms diffused to the opposite Ni interface, resulting in the formation of a thin interfacial (NiCu)3(SnZn)4 (containing 3 wt% Cu); EM significantly accelerated the diffusion of Ni atoms to the Cu interface, resulting in the formation of a large amount of (NiCu)3(SnZn)4 at the Cu interface. Even under downwind diffusion, no apparent consumption of Cu substrate was observed due to the formation of a thick and dense Cu5Zn8 layer at the Cu interface. It is more damaging with electrons flowing from Ni to Cu than that from Cu to Ni.

Keywords

Solder Joint SnZn Liquid Solder Chemical Potential Gradient Electron Wind Force 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Notes

Acknowledgements

This work is supported by the National Natural Science Foundation of China under Grant No. 51171036 and the Specialized Research Fund for the Doctoral Program of Higher Education of China under Grant No. 20120041120038.

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Copyright information

© Springer Science+Business Media New York 2013

Authors and Affiliations

  • M. L. Huang
    • 1
  • Q. Zhou
    • 1
  • N. Zhao
    • 1
  • X. Y. Liu
    • 1
  • Z. J. Zhang
    • 1
  1. 1.Electronic Packaging Materials Laboratory, School of Materials Science and EngineeringDalian University of TechnologyDalianPeople’s Republic of China

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