Microstructure and sn crystal orientation evolution in Sn-3.5Ag lead-free solders in high-temperature packaging applications

Bite Zhou, Govindarajan Muralidharan, Kanth Kurumadalli, Chad M. Parish, Scott Leslie, Thomas R. Bieler

Research output: Contribution to journalArticlepeer-review

23 Scopus citations

Abstract

Understanding the reliability of eutectic Sn-3.5Ag lead-free solders in high-temperature packaging applications is of significant interest in power electronics for the next-generation electric grid. Large-area (2.5 mm × 2.5 mm) Sn-3.5Ag solder joints between silicon dies and direct bonded copper substrates were thermally cycled between 5 C and 200 C. Sn crystal orientation and microstructure evolution during thermal cycling were characterized by electron backscatter diffraction in the scanning electron microscope. Comparisons were made between the observed initial texture and microstructure and its evolution during thermal cycling. Gradual lattice rotation and grain boundary misorientation evolution observed due to thermal cycling suggested a continuous recrystallization mechanism. Recrystallization behavior was correlated with dislocation slip activities.

Original languageEnglish
Pages (from-to)57-68
Number of pages12
JournalJournal of Electronic Materials
Volume43
Issue number1
DOIs
StatePublished - Jan 2014

Funding

The authors would like to acknowledge Jackie Mayotte for metallography. This work was spon- sored by the US Department of Energy, Office of Electricity Delivery, and by the SHaRE User Facility supported by the Scientific User Facilities Division of the Office of Science. Work at Michigan State University was also partially supported by NSF-GOALI Contract 1006656 (B.Z. and T.R.B.).

Keywords

  • High-temperature packaging
  • dislocation slip
  • recrystallization
  • texture evolution
  • thermal cycling

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