11 Scopus citations

Abstract

Tin (Sn)-rich lead (Pb)-free solders containing rare-earth (RE) elements have been shown to exhibit desirable attributes of microstructural refinement and enhanced ductility relative to conventional Sn-3.9Ag-0.7Cu lead-free solder, due to the unique mechanical properties of RE-Sn intermetallics. However, the roles of soft intermetallic phase in the enhanced ductility of Pb-free solder still need to be further investigated. In this paper, Ca and Mn were selected as doping elements for Sn-Ag-Cu solder. The mechanical properties of Ca-Sn and Mn-Sn intermetallics as a function of indentation depth were measured by nanoindentation using the continuous stiffness method (CSM). The microstructure and mechanical properties of as-reflowed Ca- and Mn-containing Sn-Ag-Cu solder joints were studied and compared with those of conventional Sn-Ag-Cu and RE-containing solder joints. It is shown that soft intermetallics result in higher ductility in Pb-free solders.

Original languageEnglish (US)
Pages (from-to)527-536
Number of pages10
JournalJournal of Electronic Materials
Volume42
Issue number3
DOIs
StatePublished - Jan 7 2013

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Keywords

  • Lead-free solder
  • Young's modulus
  • calcium
  • hardness
  • intermetallic
  • manganese
  • nanoindentation

ASJC Scopus subject areas

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

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