Journal of Electronic Materials

, Volume 33, Issue 12, pp 1545–1549

Quantitative metallography of β-Sn dendrites in Sn-3.8Ag-0.7Cu ball grid array solder balls via electron backscatter diffraction and polarized light microscopy

  • A. LaLonde
  • D. Emelander
  • J. Jeannette
  • C. Larson
  • W. Rietz
  • D. Swenson
  • D. W. Henderson
Special Issue Paper

DOI: 10.1007/s11664-004-0096-8

Cite this article as:
LaLonde, A., Emelander, D., Jeannette, J. et al. Journal of Elec Materi (2004) 33: 1545. doi:10.1007/s11664-004-0096-8

Abstract

Electron backscatter diffraction and polarized light microscopy have been used to quantify the number of crystallographically independent β-Sn dendrites present in near-eutectic, ball grid array Sn-Ag-Cu (SAC) solder balls as a function of cooling rate (0.35–3.0°C/s). Based on these data, it is estimated that a single 900-µm-diameter solder ball contains on average eight individual β-Sn dendrites, independent of cooling rate. Specific orientation relationships were also found to be prevalent between neighboring β-Sn dendrites. These results confirm and expand upon recent research, and further emphasize the probable anisotropic nature of SAC solder joints.

Key Words

Pb-free solderSn-Ag-Cudendrite orientationβ-Snelectron backscatter diffractionpolarized light microscopytwinning

Copyright information

© TMS-The Minerals, Metals and Materials Society 2004

Authors and Affiliations

  • A. LaLonde
    • 1
  • D. Emelander
    • 1
  • J. Jeannette
    • 1
  • C. Larson
    • 1
  • W. Rietz
    • 1
  • D. Swenson
    • 1
  • D. W. Henderson
    • 2
  1. 1.Department of Materials Science and EngineeringMichigan Technological UniversityHoughton
  2. 2.IBM MicroelectronicsEast Fishkill