Influence of SrTiO3 nano-particles on the microstructure and shear strength of Sn-Ag-Cu solder on Au/Ni metallized Cu pads

Tama Fouzder, Ismathullakhan Shafiq, Y. C. Chan, A. Sharif, Kam Chuen Yung

Research output: Journal article publicationJournal articleAcademic researchpeer-review

65 Citations (Scopus)


Nano-sized, nonreacting, noncoarsening SrTiO3particles have been incorporated into Sn-3.0 wt% Ag-0.5 wt% Cu solder alloys and the interfacial microstructure and the shear strength on Au/Ni metallized Cu pads ball grid array substrates investigated as a function of the number of reflow cycles and aging time. At their interfaces, a scallop-shaped ternary Sn-Ni-Cu intermetallic compound layer was found in both plain Sn-Ag-Cu solder joints and solder joints containing SrTiO3nano-particles, and the intermetallic compound layer thickness increased with the number of reflow cycles and aging time. After the addition of SrTiO3nano-particles, in the solder ball region, a fine microstructure of AuSn4, Ag3Sn, Cu6Sn5intermetallic compounds appeared in the β-Sn matrix. In addition, the shear strength of solder joints containing SrTiO3nano-particles exhibited a consistently higher value than that of plain Sn-Ag-Cu solder joints due to a second phase dispersion strengthening mechanism as well as a refinement of the intermetallic compounds. The fracture surface of plain Sn-Ag-Cu solder joints exhibited a brittle fracture mode with a smooth surface while Sn-Ag-Cu solder joints containing SrTiO3nano-particles showed ductile failure characteristics with rough dimpled surfaces.
Original languageEnglish
Pages (from-to)1885-1892
Number of pages8
JournalJournal of Alloys and Compounds
Issue number5
Publication statusPublished - 3 Feb 2011


  • Ball grid array solder joints
  • Microstructure
  • Nano doping
  • Shearing force

ASJC Scopus subject areas

  • Mechanical Engineering
  • Mechanics of Materials
  • Materials Chemistry
  • Metals and Alloys

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