Abstract

Solders serve as electrical and mechanical interconnects in electronic packaging. The mechanical shock behavior of a Pb-free solder joint is quite complex, since the influences of solder microstructure, intermetallic compound (IMC) layer thickness, and strain rate on the overall dynamic solder joint strength need to be quantified. Dynamic solder joint strength is hypothesized to be controlled by two factors. At low strain rates it should be controlled by the bulk solder, whereas at high strain rates it may be controlled by the brittle intermetallic compound layer. In this paper, the dynamic solder joint strength of Sn-3.9 Ag-0.7 Cu solder joints was experimentally measured over the strain rate range 10 -3-12 s -1. The influences of changes in solder microstructure and IMC layer on dynamic solder joint strength were quantified, and visualized in three dimensions. Fracture mechanisms operating in the solder-controlled and IMC layer-controlled dynamic strength regimes are discussed. Finally, qualitative numerical simulations were conducted, which accurately depict the experimentally observed fracture behaviors.

Original languageEnglish (US)
Pages (from-to)4336-4348
Number of pages13
JournalActa Materialia
Volume60
Issue number10
DOIs
StatePublished - Jun 1 2012

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Keywords

  • Cu Sn
  • Fracture
  • Mechanical shock
  • Pb-free solder
  • Strain rate

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Polymers and Plastics
  • Metals and Alloys

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