Special Feature : Plasma-induced Interface Reaction and Surface Science
Surface Reactions Induced by Gas Cluster Ion Beams and Application for Atomic Layer Etching
2020 Volume 63 Issue 12 Pages 623-628
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2020 Volume 63 Issue 12 Pages 623-628
Atomic layer etchings (ALE) with gas cluster ion beam (GCIB) were reviewed. Gas cluster ions are aggregates of thousands of atoms or molecules. Thus, energy/atom of gas cluster ions are easily reduced to several eV/atom. In addition, gas cluster ions realize transient high-temperature and high-pressure conditions on the bombard area, enhancement of chemical reaction and removal of chemically altered surface layer are expected. These irradiation effects are beneficial for ALE. In this report, ALE of metal films (Cu or Ni) by oxygen GCIB (O2-GCIB) with acetic acid or acetylacetone (acac) vapor were investigated. Metal oxide layer was removed owing to chemical reactions with acetic acid or acac included by 5 kV O2-GCIB irradiation. Since there was no physical sputtering by 5 kV O2-GCIB, etching terminated after removal of surface layer.
