In Situ TEM Observations of Cu6Sn5 Polymorphic Transformations in Reaction Layers Between Sn-0.7Cu Solders and Cu Substrates

Kazuhiro Nogita, M. A.A. Mohd Salleh, E. Tanaka, G. Zeng, S. D. McDonald, S. Matsumura

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

Direct evidence of the relationship between the polymorphic phase transformation from monoclinic Cu6Sn5 to hexagonal Cu6Sn5 and stress accumulation/release in Cu6Sn5, formed at the interface between Sn-0.7Cu lead-free solder and their Cu substrates, has been obtained. To explore this challenging phenomenon, we developed an in situ heating/isothermal observation technique in ultrahigh-voltage transmission electron microscopy that enables the observation of thick samples (around 0.5 μm) for solder joints, including Cu/Cu3Sn/Cu6Sn5/Sn-0.7Cu solder interfaces prepared by a focused ion beam milling technique. The results show evidence of stress creation and release events by imaging bend contours that may arise due to the polymorphic transformations of the Cu6Sn5 phase and the associated volumetric change.

Original languageEnglish
Pages (from-to)2871-2878
Number of pages8
JournalJOM
Volume68
Issue number11
DOIs
Publication statusPublished - Nov 1 2016

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Engineering(all)

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