Plasma etching for carbon materials by inward RF plasma apparatus

ABSTRACT

Diamond has high wear resistance and shape stability, and poly-crystalline chemical vapour deposition (CVD) diamond is difficult to mechanically process because of cleavage and wear anisotropy. On the other hand, diamond can be removed under an oxidising atmosphere with O₂ as the etching gas by reactive ion etching which is processing using plasma. In this study, the fabrication of an inward radio frequency (RF) plasma apparatus and the possibility of a removal process for carbon materials such as CVD diamond film and graphite plate by using it were investigated. OES, confocal laser scanning microscope and Raman spectroscopy were used for the evaluation of the etching. It was confirmed that the inward RF plasma apparatus fabricated could be applied to plasma etching for carbon materials. In addition, it was suggested that carbon materials were etched as CO with O₂ in the atmosphere, and amorphous structures were etched preferentially over crystalline ones.

KEYWORDS:

• CVD diamond
• plasma etching
• RF
• graphite
• oxidising
• OES
• Raman spectroscopy
• etching rate

Acknowledgements

Thanks are due to Tomoya Matsumoto for cooperation in the experiments. This paper is based on a presentation given at Interfinish2020, held online 6–8 September 2021, organised by the Surface Finishing Society of Japan, co-organised by Nagoya University and supported by the International Union for Surface Finishing (IUSF).

Disclosure statement

No potential conflict of interest was reported by the author(s).