Mechanical characterization of lead-free Sn-Ag-Cu solder joints by high-temperature nanoindentation

S. Lotfian, J. M. Molina-Aldareguia, K. E. Yazzie, J. Llorca, Nikhilesh Chawla

Research output: Contribution to journalArticlepeer-review

34 Scopus citations


The reliability of Pb-free solder joints is controlled by their microstructural constituents. Therefore, knowledge of the solder microconstituents' mechanical properties as a function of temperature is required. Sn-Ag-Cu lead-free solder alloy contains three phases: a Sn-rich phase, and the intermetallic compounds (IMCs) Cu6Sn5 and Ag3Sn. Typically, the Sn-rich phase is surrounded by a eutectic mixture of β-Sn, Cu6Sn5, and Ag3Sn. In this paper, we report on the Young's modulus and hardness of the Cu 6Sn5 and Cu3Sn IMCs, the β-Sn phase, and the eutectic compound, as measured by nanoindentation at elevated temperatures. For both the β-Sn phase and the eutectic compound, the hardness and Young's modulus exhibited strong temperature dependence. In the case of the intermetallics, this temperature dependence is observed for Cu 6Sn5, but the mechanical properties of Cu3Sn are more stable up to 200 C.

Original languageEnglish (US)
Pages (from-to)1085-1091
Number of pages7
JournalJournal of Electronic Materials
Issue number6
StatePublished - Jun 2013


  • High-temperature nanoindentation
  • Sn-Ag-Cu solder
  • intermetallics
  • lead-free solder

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering
  • Materials Chemistry


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