Effects of high-temperature treatment on the reaction between Sn-3%Ag-0.5%Cu solder and sputtered Ni-V film on ferrite substrate

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review

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  • Xiaohu Shen
  • Hao Jin
  • Shurong Dong
  • Jian Zhou
  • Zhaodi Guo
  • Demiao Wang

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Original languageEnglish
Pages (from-to)3145-3151
Journal / PublicationJournal of Electronic Materials
Issue number11
Publication statusPublished - Nov 2012


We have demonstrated a novel sputtering method for lead-free thin metal films on ferrite substrates for surface-mount inductor applications. In a surface- mounting process, the cladding of enameled wire needs to be burnt off at high temperature, which requires the devices to withstand a high-temperature reliability test at 420°C for 10 s. There are no reports that a sputtered film of thickness less than 6 lm can withstand this test. In this work, we used Ag/Ni-7 wt.%V double metal layers for the metallization. The dissolution of Ni-7 wt.%V in Sn-3%Ag-0.5%Cu lead-free solder at various temperatures was studied in detail. Scanning electron microscopy with energy-dispersive x-ray spectroscopy was used to investigate the interfacial reaction between the sputtered films and the solder. The intermetallic compounds are mainly (Cu,Ni) 6Sn 5 at 250°C; however, (Ni,Cu) 3Sn 4 becomes the predominant composition at 420°C. In addition, although outdiffusion of V atoms from the Ni-V layer was observed, its effect on the intermetallic compound (IMC) was insignificant. We further confirmed that the proposed metallization is able to pass the aforementioned high-temperature reliability test. © 2012 TMS.

Research Area(s)

  • Ferrite metallization, Intermetallic compounds, Lead-free solder, Magnetron sputtering

Citation Format(s)