63rd Annual Gaseous Electronics Conference and 7th International Conference on Reactive Plasmas
Volume 55, Number 7
Monday–Friday, October 4–8, 2010;
Paris, France
Session VF1: Capacitively-Coupled Plasmas
4:00 PM–6:00 PM,
Friday, October 8, 2010
Room: 151
Chair: Miles Turner, Dublin City University
Abstract ID: BAPS.2010.GEC.VF1.4
Abstract: VF1.00004 : Electrode Impedance Effect in a CCP reactor
5:00 PM–5:30 PM
Preview Abstract
Abstract
Author:
Yohei Yamazawa
(Tokyo Electron AT LTD.)
The generation of harmonics of drive frequency is of great
technological importance in CCP reactors. It is commonly observed
that a minor change in an external circuit, such as changing the
cable length between the RF power supply and the matcher, brings
about a significant difference both in the
amplitude of harmonics and in process results.
Recently, Mussenbrock and Brinkmann proposed a nonlinear electron
resonance heating (NERH) model that predicts the enhanced
dissipation caused by the harmonics originating from the series
resonance between plasma bulk and sheath [1]. This theory gives a
good explanation of the change in the amplitude of harmonics and
in plasma property. However, there is a
discrepancy between the simplified theory and observed result.
The theory predicts that the resonant growth of harmonics takes
place for frequencies greater than 100 MHz, given the typical
inductance of the bulk and capacitance of the sheath. On the
other hand, the frequencies of the harmonics which are commonly
observed to grow tend to be lower than 100 MHz.
By taking into account the external circuit in the series
resonance condition, the resonance is possible at a frequency
below 100MHz. We have experimentally demonstrated the resonant
growth of the second, third and forth harmonics of a 13.56MHz
drive frequency by tuning an external circuit [2]. We also
observed an increase in electron density as the amplitude of
the harmonics grows [3]. Thus, the external circuit modifies the
impedance of the electrode and the change in impedance has
significant effect on the growth of the harmonics, and the growth
of these harmonics brings about an increase in electron density.
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[1] T. Mussenbrock and R. P. Brinkmann, Appl. Phys. Lett. 88,
151503 (2006)
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[2] Y. Yamazawa, M. Nakaya, M. Iwata and A. Shimizu, Jpn. J.
Appl. Phys., Part 1 46, 7453 (2007)
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[3] Y. Yamazawa, Appl. Phys. Lett. 95, 191504 (2009)
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2010.GEC.VF1.4