Journal of Electronic Materials

, Volume 33, Issue 12, pp 1485–1496

Elevated temperature aging of solder joints based on Sn-Ag-Cu: Effects on joint microstructure and shear strength

  • I. E. Anderson
  • J. L. Harringa
Special Issue Paper

DOI: 10.1007/s11664-004-0090-1

Cite this article as:
Anderson, I.E. & Harringa, J.L. Journal of Elec Materi (2004) 33: 1485. doi:10.1007/s11664-004-0090-1

Abstract

The shear strength behavior and microstructural effects after aging for 100 h and 1,000 h at 150°C are reported for near-eutectic Sn-Ag-Cu (SAC) solder joints (joining to Cu) made from Sn-3.5Ag (wt.%) and a set of SAC alloys (including Co- and Fe-modified SAC alloys). All joints in the as-soldered and 100-h aged condition experienced shear failure in a ductile manner by either uniform shear of the solder matrix (in the strongest solders) or by a more localized shear of the solder matrix adjacent to the Cu6Sn5 interfacial layer, consistent with other observations. After 1,000 h of aging, a level of embrittlement of the Cu3Sn/Cu interface can be detected in some solder joints made with all of the SAC alloys and with Sn-3.5Ag, which can lead to partial debonding during shear testing. However, only ductile failure was observed in all solder joints made from the Co- and Fe-modified SAC alloys after aging for 1,000 h. Thus, the strategy of modifying a strong (high Cu content) SAC solder alloy with a substitutional alloy addition for Cu seems to be effective for producing a solder joint that retains both strength and ductility for extended isothermal aging at high temperatures.

Key words

Lead-free soldershear strengthjoint microstructurethermal aging

Copyright information

© TMS-The Minerals, Metals and Materials Society 2004

Authors and Affiliations

  • I. E. Anderson
    • 1
  • J. L. Harringa
    • 1
  1. 1.Ames Laboratory (USDOE)Iowa State UniversityAmes