Journal of Electronic Materials

, Volume 33, Issue 12, pp 1524–1529 | Cite as

Intermetallic phase detection in lead-free solders using synchrotron x-ray diffraction

  • Gavin J. Jackson
  • Hua Lu
  • Raj Durairaj
  • Nick Hoo
  • Chris Bailey
  • Ndy N. Ekere
  • Jon Wright
Special Issue Paper

Abstract

The high-intensity, high-resolution x-ray source at the European Synchrotron Radiation Facility (ESRF) has been used in x-ray diffraction (XRD) experiments to detect intermetallic compounds (IMCs) in lead-free solder bumps. The IMCs found in 95.5Sn3.8Ag0.7Cu solder bumps on Cu pads with electroplated-nickel immersion-gold (ENIG) surface finish are consistent with results based on traditional destructive methods. Moreover, after positive identification of the IMCs from the diffraction data, spatial distribution plots over the entire bump were obtained. These spatial distributions for selected intermetallic phases display the layer thickness and confirm the locations of the IMCs. For isothermally aged solder samples, results have shown that much thicker layers of IMCs have grown from the pad interface into the bulk of the solder. Additionally, the XRD technique has also been used in a temperature-resolved mode to observe the formation of IMCs, in situ, during the solidification of the solder joint. The results demonstrate that the XRD technique is very attractive as it allows for nondestructive investigations to be performed on expensive state-of-the-art electronic components, thereby allowing new, lead-free materials to be fully characterized.

Key words

X-ray diffraction (XRD) synchrotron intermetallic compounds (IMCs) lead-free solder reliability European Synchrotron Radiation Facility (ESRF) 

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Copyright information

© TMS-The Minerals, Metals and Materials Society 2004

Authors and Affiliations

  • Gavin J. Jackson
    • 1
  • Hua Lu
    • 2
  • Raj Durairaj
    • 3
  • Nick Hoo
    • 4
  • Chris Bailey
    • 2
  • Ndy N. Ekere
    • 3
  • Jon Wright
    • 5
  1. 1.Henkel TechnologiesHertfordshireUK
  2. 2.CMS, University of GreenwichLondonUK
  3. 3.School of EngineeringUniversity of GreenwichChathamUK
  4. 4.Tin Technology Ltd.UK
  5. 5.ESRF, Polygone Scientifique Louis NéelGrenobleFrance

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