Investigation of multi-component lead-free solders

M. E. Loomans*, S. Vaynman, G. Ghosh, M. E. Fine

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

108 Scopus citations

Abstract

Binary phase diagrams of interest for lead-free solder development have been entered into the THERMO-CALC data base. These may be used directly to calculate multi-component phase relations vs temperature provided there are no ternary or higher order interactions. Such occur in the Sn-Ag-Zn system and are being evaluated. Contact angles of a number of solder-flux combinations on copper were directly measured in spreading tests. With a rosin-isopropyl alcohol flux, the contact angles of binary eutectic solders were in degrees: Sn-Bi at 166°C, 40; Sn-Zn at 225°C, 60; Sn-Ag at 250°C, 45. These angles were little affected by a number of 1% ternary additions to the solder. The contact angles were 20 degrees or less when SnCl2 was used as a flux. The SnCl2 reacts with Cu to form Cu3Sn. The most likely successful approach to obtain satisfactory wetting with lead-free solders appears to be development of a satisfactory flux.

Original languageEnglish (US)
Pages (from-to)741-746
Number of pages6
JournalJournal of Electronic Materials
Volume23
Issue number8
DOIs
StatePublished - Aug 1 1994

Keywords

  • Contact angle
  • lead-free solders
  • wettability

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)
  • Electronic, Optical and Magnetic Materials
  • Materials Science(all)
  • Electrical and Electronic Engineering
  • Condensed Matter Physics
  • Materials Chemistry

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