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Proceedings Paper

Electrical measurements for monitoring and control of rf plasma processing
Author(s): Mark A. Sobolewski; James R. Whetstone
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Paper Abstract

We have investigated the possibility of using current and voltage measurements for real-time monitoring and control of radio-frequency discharges. Specifically, we have equipped a gaseous electronics conference (GEC) rf reference cell with a computer-controlled measurement system that samples the voltage and current waveforms at the cell power input and Fourier analyzes these waveforms to obtain the amplitude and phase of their fundamental and harmonic components. The system accounts for errors introduced by the stray impedance of the cell, yielding corrected values that more accurately reflect the values of voltage and current at electrode surfaces in contact with the plasma. These corrected values are monitored to reveal changes in fundamental plasma parameters such as sheath voltages, sheath fields, and sheath (dark space) thicknesses. Furthermore, the corrected values serve as better control parameters than the raw values of voltage, current or power, measured externally. The time required for the acquisition and analysis of a pair of current and voltage waveforms is approximately one second, making these measurements suitable for real-time sensing and control applications.

Paper Details

Date Published: 16 April 1993
PDF: 12 pages
Proc. SPIE 1803, Advanced Techniques for Integrated Circuit Processing II, (16 April 1993); doi: 10.1117/12.142926
Show Author Affiliations
Mark A. Sobolewski, National Institute of Standards and Technology (United States)
James R. Whetstone, National Institute of Standards and Technology (United States)

Published in SPIE Proceedings Vol. 1803:
Advanced Techniques for Integrated Circuit Processing II
James A. Bondur; Gary Castleman; Lloyd R. Harriott; Terry R. Turner, Editor(s)

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