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Interfacial reactions between Sn-3.5 Ag solder and Ni-W alloy films
Journal of Materials Science-Materials in Electronics (2011)

Nickel based alloys are currently being investigated in an effort to develop stable barrier films between lead free solder and copper substrate. In this study, interfacial reactions between Ni-W alloy films and Sn-3.5 Ag solder have been investigated. Ni-W alloys films with tungsten content in the range of 5.0-18.0 at.% were prepared on copper substrate by electrodeposition in ammonia citrate bath. Solder joints were prepared on the Ni-W coated substrate at a reflow temperature of 250 °C. The solder joint interface was investigated by Cross-sectional scanning electron microscopy, energy dispersive X-ray spectroscopy and electron back scatter diffraction. It has been observed that a Ni3Sn4 layer with faceted morphology formed on the Ni-W alloy film after reflow. The thickness of the bright layer was found to decrease with the increase of tungsten content in the Ni-W film. An additional layer with a bright appearance was also found to form below the Ni3Sn4 layer. The bright layer was identified to be a ternary phase containing Sn, W and Ni. The bright layer is found to be amorphous and is suggested to have formed through solid state amorphization caused by anomalously fast diffusion of Sn into Ni-W film. © Springer Science+Business Media, LLC 2011.

  • Barrier films,
  • Bright layer,
  • Citrate baths,
  • Coated substrates,
  • Copper substrates,
  • Cross-sectional scanning electron microscopies,
  • Electron back scatter diffraction,
  • Energy dispersive X ray spectroscopy,
  • Faceted morphology,
  • Fast diffusion,
  • Lead free solders,
  • Ni-W alloy,
  • Nickel based alloy,
  • Reflow temperatures,
  • Solder joints,
  • Solid-state amorphization,
  • Ternary phase,
  • Tungsten content,
  • Alloys,
  • Amorphous films,
  • Cerium alloys,
  • Film preparation,
  • Investments,
  • Metallic films,
  • Scanning electron microscopy,
  • Silver,
  • Silver alloys,
  • Tin alloys,
  • Tungsten,
  • Tungsten alloys,
  • X ray spectroscopy,
  • Tin
Publication Date
Citation Information
"Interfacial reactions between Sn-3.5 Ag solder and Ni-W alloy films" Journal of Materials Science-Materials in Electronics Vol. 22 Iss. 9 (2011)
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