Cu film thermal stability on plasma cleaned polycrystalline Ru

Xin Liu, Chiyu Zhu, Brianna S. Eller, Tianyin Sun, Christopher J. Jezewski, Sean W. King, Robert Nemanich

Research output: Contribution to journalArticlepeer-review

5 Scopus citations


The first part of this study examined oxide stability and cleaning of Ru surfaces. The surface reactions during H2 plasma exposure of Ru polycrystalline films were studied using x-ray photoelectron spectroscopy (XPS). The ∼2 monolayer native Ru oxide was reduced after H-plasma processing. However, absorbed oxygen, presumably in the grain boundaries, remains after processing. A vacuum thermal anneal at 150 °C substantially removes both surface oxide and absorbed oxygen which is attributed to a reduction by carbon contamination. The second part of the study examined the thermal stability of Cu on a Ru layer. The thermal stability or islanding of the Cu film on the Ru substrate was characterized by in situ XPS. After plasma cleaning of the Ru adhesion layer, the deposited Cu exhibited full coverage. In contrast, for Cu deposition on the Ru native oxide substrate, Cu islanding was detected and was described in terms of grain boundary grooving and surface and interface energies. The oxygen in the grain boundary has a negligible contribution to the surface energy and does not contribute to Cu islanding.

Original languageEnglish (US)
Article number052203
JournalJournal of Vacuum Science and Technology B:Nanotechnology and Microelectronics
Issue number5
StatePublished - Sep 2012

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Instrumentation
  • Process Chemistry and Technology
  • Surfaces, Coatings and Films
  • Electrical and Electronic Engineering
  • Materials Chemistry


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