Characterization of SiO 2 Plasma Etching with Perfluorocarbon (C 4 F 8 and C 6 F 6 ) and Hydrofluorocarbon (CHF 3 and C 4 H 2 F 6 ) Precursors for the Greenhouse Gas Emissions Reduction.

This paper proposes the use of environmentally friendly alternatives, C 6 F 6 and C 4 H 2 F 6 , as perfluorocarbon (PFC) and hydrofluorocarbon (HFC) precursors, respectively, for SiO 2 plasma etching, instead of conventional precursors C 4 F 8 and CHF 3 . The study employs scanning electron microscopy for etch profile analysis and quadrupole mass spectrometry for plasma diagnosis. Ion bombardment energy at the etching conditions is determined through self-bias voltage measurements, while densities of radical species are obtained using quadrupole mass spectroscopy. The obtained results compare the etch performance, including etch rate and selectivity, between C 4 F 8 and C 6 F 6 , as well as between CHF 3 and C 4 H 2 F 6 . Furthermore, greenhouse gas (GHG) emissions are evaluated using a million metric ton of carbon dioxide equivalent, indicating significantly lower emissions when replacing conventional precursors with the proposed alternatives. The results suggest that a significant GHG emissions reduction can be achieved from the investigated alternatives without a deterioration in SiO 2 etching characteristics. This research contributes to the development of alternative precursors for reducing global warming impacts.