AVS 46th International Symposium
    Plasma Science and Technology Division Monday Sessions
       Session PS-MoA

Paper PS-MoA5
Optical Emission Thermometry Applied to the Measurement of Neutral Gas Temperature within a High-density, Inductively-coupled Plasma Abatement Device

Monday, October 25, 1999, 3:20 pm, Room 609

Session: Plasma Diagnostics I
Presenter: E.J. Tonnis, University of California, Berkeley
Authors: D.B. Graves, University of California, Berkeley
E.J. Tonnis, University of California, Berkeley
M.W. Kiehlbauch, University of California, Berkeley
Correspondent: Click to Email
Flowing plasma reactors have proven important as downstream sources of reactive species and show promise for applications such as abatement of perfluorocompounds and other environmentally harmful effluents produced by the semiconductor industry. Recent spectroscopic measurements and simulation predictions in a inductively-coupled plasma source indicate that at high input powers, the neutral gas temperature within the plasma zone can be many times higher than ambient (> 1500 K) depending upon the plasma chemistry. High neutral-gas temperature could alter the dominant chemical mechanisms in the plasma and it is therefore important to measure and compare these results to model predictions. In this work, the neutral temperature of flowing CF@sub 4@/O@sub 2@, C@sub 2@F@sub 6@/O@sub 2@, and CF@sub 4@/H@sub 2@O plasmas was measured at varying input conditions using optical emission thermometry techniques. It was found that the rotational temperature, which was assumed to thermalize with translational temperature, is sensitive to the chemical nature of the plasma. In particular, C@sub 2@-derived (516.5 nm) emission temperatures measured within a CF@sub 4@/O@sub 2@ plasma were estimated at greater than 2000 K, which is several times higher than N@sub 2@-derived (399.8 nm) temperatures (~500 K) observed within a pure N@sub 2@ discharge over the same range of pressures and powers. In addition, the rotational temperatures were found to be relatively insensitive to the input power as long as a high-density discharge was sustained.