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Mechanism of Dry Etching of Silicon Dioxide: a Case of Direct Reactive Ion Etching

Published online by Cambridge University Press:  21 February 2011

Ch. Steinbruchel
Affiliation:
Laboratories RCA Ltd., Badenerstrasse 569, CH-8048 Zurich, Switzerland
H. W. Lehmann
Affiliation:
Laboratories RCA Ltd., Badenerstrasse 569, CH-8048 Zurich, Switzerland
K. Frick
Affiliation:
Laboratories RCA Ltd., Badenerstrasse 569, CH-8048 Zurich, Switzerland
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Abstract

Reactive sputter etching of SiO2 with CHF3-O2 plasmas has been investigated in a parallel plate reactor by combining etch rate measurements with concurrent determination of ion densities (using a Langmuir probe) and the composition of neutral plasma species (using a mass spectrometer). Etch rates are found to follow the ion density and to be fairly independent of the plasma chemistry under most experimental conditions. Moreover, a comparison of reactive sputter etching and reactive ion beam etching of SiO2 with CHF3 and CF4 shows that etch yields per incoming ion are essentially independent of the flux of neutral radicals to the substrate. This strongly suggests as the dominant etch mechanism for SiO2 direct reactive ion etching, where ions themselves are the main reactants in the etch reaction. Measured values of etch yields are consistent with this picture.

Type
Research Article
Copyright
Copyright © Materials Research Society 1985

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