Abstract
The etching rates and reaction products of refractory metals (W, Mo, and Ta) and silicon have been studied in a SF6-O2 r.f. plasma at 0.2 torr. The relative concentrations of WF6 and WOF4 and the intensities of the WF + n (n=3−5), WOF + m (m=1−3), MoF + n , and MoF + m ions have been measured by mass spectroscopy. An analysis of the neutral composition of the plasma during etching of these metals and a comparison with the results obtained for silicon show that at least two species are involved for W and Mo etching: fluorine and oxygen atoms. A reaction scheme is proposed.
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Picard, A., Turban, G. Plasma etching of refractory metals (W, Mo, Ta) and silicon in SF6 and SF6-O2. An analysis of the reaction products. Plasma Chem Plasma Process 5, 333–351 (1985). https://doi.org/10.1007/BF00566008
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DOI: https://doi.org/10.1007/BF00566008