Journal of Electronic Materials

, Volume 23, Issue 8, pp 765–772 | Cite as

Microstructure evolution of eutectic Sn-Ag solder joints

  • Wenge Yang
  • Robert W. Messler
  • Lawrence E. Felton
Special Issue Papers


Laser and infrared reflow soldering methods were used to make Sn-Ag eutectic solder joints for surface-mount components on printed wiring boards. The microstructures of the joints were evaluated and related to process parameters. Aging tests were conducted on these joints for times up to 300 days and at temperature up to 190°C. The evolution of microstructure during aging was examined. The results showed that Sn-Ag solder microstructure is unstable at high temperature, and microstructural evolution can cause solder joint failure. Cu-Sn intermetallics in the solder and at copper-solder interfaces played an important role in both the microstructure evolution and failure of solder joints. Void and crack formation in the aged joints was also observed.

Key words

Intermetallics laser-soldering lead-free solder 


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Copyright information

© The Metallurgical of Society of AIME 1994

Authors and Affiliations

  • Wenge Yang
    • 1
  • Robert W. Messler
    • 1
  • Lawrence E. Felton
    • 2
  1. 1.Materials Engineering DepartmentRensselaer Polytechnic InstituteTroy
  2. 2.Design and Manufacturing Institute, Rensselaer Polytechnic InstituteTroy

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