Journal of Electronic Materials

, Volume 40, Issue 9, pp 1895–1902

Correlation Between Sn Grain Orientation and Corrosion in Sn-Ag-Cu Solder Interconnects

  • Tae-Kyu Lee
  • Bo Liu
  • Bite Zhou
  • Thomas Bieler
  • Kuo-Chuan Liu
Article

DOI: 10.1007/s11664-011-1654-5

Cite this article as:
Lee, TK., Liu, B., Zhou, B. et al. Journal of Elec Materi (2011) 40: 1895. doi:10.1007/s11664-011-1654-5

Abstract

The impact of a marine environment on Sn-Ag-Cu interconnect reliability is examined using salt spray exposure followed by thermal cycling. Sn-Ag-Cu solder alloy wafer-level packages, with and without pretreatment with 5% NaCl salt spray, were thermally cycled to failure. The prior salt spray reduced the characteristic lifetime of the Sn-Ag-Cu solder joints by over 43%. Although Sn-based materials show strong resistance to corrosion, the nature of localized corroded areas at critical locations in the solder joint caused significant degradation in the Sn-Ag-Cu solder joints. An important link between the corrosion path and Sn grain orientation was observed using orientation imaging microscopy (OIM). A strong correlation between the corrosion path and grain orientation was identified, indicating that the corrosion attack preferentially followed the basal plane of the Sn lattice.

Keywords

Pb-free solder Sn grain orientation salt spray corrosion orientation image microscopy (OIM) thermal fatigue 

Copyright information

© TMS 2011

Authors and Affiliations

  • Tae-Kyu Lee
    • 1
  • Bo Liu
    • 1
  • Bite Zhou
    • 2
  • Thomas Bieler
    • 2
  • Kuo-Chuan Liu
    • 1
  1. 1.Component Quality and Technology Group, Cisco Systems, Inc.San JoseUSA
  2. 2.Chemical Engineering and Materials ScienceMichigan State UniversityEast LansingUSA

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