Interfacial reaction between multicomponent lead-free solders and Ag, Cu, Ni, and Pd substrates

G. Ghosh*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

33 Scopus citations

Abstract

The interfacial reaction between two prototype multicomponent lead-free solders, Sn-3.4Ag-1Bi-0.7Cu-4In and Sn-3.4Ag-3Bi-0.7Cu-4In (mass%), and Ag, Cu, Ni, and Pd substrates are studied at 250°C and 150°C. The microstructural characterization of the solder bumps is carried out by scanning electron microscopy (SEM) coupled with energy dispersive x-ray analysis. Ambient temperature, isotropic elastic properties (bulk, shear, and Young's moduli and Poisson's ratio) of these solders along with eutectic Sn-Ag, Sn-Bi, and Sn-Zn solders are measured. The Isotropic elastic moduli of multicomponent solders are very similar to the eutectic Sn-Ag solder. The measured solubility of the base metal in liquid solders at 250°C agrees very well with the solubility limits reported in assessed Sn-X (X = Ag, Cu, Ni, Pd) phase diagrams. The measured contact angles were generally less than 15° on Cu and Pd substrates, while they were between 25° and 30° on Ag and Ni substrates. The observed intermediate phases in Ag/solder couples were Ag3Sn after reflow at 250°C and Ag3Sn and ζ (Ag-Sn) after solid-state aging at 150°C. In Cu/solder and Ni/solder couples, the interfacial phases were Cu6Sn5 and (Cu,Ni) 6Sn5, respectively. In Pd/solder couples, only PdSn 4 after 60-sec reflow, while both PdSn4 and PdSn 3 after 300-sec reflow, were observed.

Original languageEnglish (US)
Pages (from-to)1080-1091
Number of pages12
JournalJournal of Electronic Materials
Volume33
Issue number10
DOIs
StatePublished - Oct 2004
Externally publishedYes

Keywords

  • Contact angle
  • Dissolution
  • Elastic properties
  • Interfacial reaction
  • Intermetallic compounds
  • 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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