Consequences of particulate charging in RF discharge sheaths
- Los Alamos National Lab., NM (United States). Applied Theoretical Physics Division
The properties and dynamics of particulates in rf plasma processing reactors remain a major concern for contamination reduction. Laser scattering measurements have shown that the particulates are charged and tend to collect in certain well defined regions of the reactor, while theory has demonstrated that the particulates are subject to a number of forces (the ion drag and electric forces usually being dominant) that tend to balance at the edge of the sheath. In this paper the authors discuss an extension to a one-dimensional force balance analysis at the edge of an rf sheath by the inclusion the effect of the finite charging time of the particulates compared to the period of the rf driven electrode. They determine how the time averaged charge on the particulates is modified, as a function of the plasma, contaminants, and rf parameters. The corresponding modifications to the ion drag and electric forces acting on the particulates and resulting changes in the equilibrium positions of the particulates are also presented. Furthermore, consequences for lower pressure, higher plasma density (> 10{sup 11} cm{sup {minus}3}) devices are considered.
- OSTI ID:
- 63068
- Report Number(s):
- CONF-940604--; ISBN 0-7803-2006-9
- Country of Publication:
- United States
- Language:
- English
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