IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Plasma Science Tuesday Sessions
       Session PS1-TuM

Paper PS1-TuM10
Submillimeter Absorption Spectroscopy of an Inductively Coupled Plasma

Tuesday, October 30, 2001, 11:20 am, Room 103

Session: Diagnostics II
Presenter: E.C. Benck, National Institute of Standards and Technology
Authors: E.C. Benck, National Institute of Standards and Technology
G. Golubiatnikov, National Institute of Standards and Technology
G. Fraser, National Institute of Standards and Technology
Correspondent: Click to Email
Millimeter and submillimeter (100 GHz to 1 THz) absorption spectroscopy is being developed as a sensor for measuring radical densities and temperatures in processing plasmas for microelectronics. Most molecules, radicals, and ions have transitions suitable for detection with submillimeter waves and the necessary spectroscopic data is available in the literature for determining the absolute radical densities. In addition, the narrow linewidths of cw submillimeter sources are suitable for measuring rotational, vibrational and translational temperatures of radicals. Initial measurements are being conducted with a backward wave oscillator (BWO) source and a liquid-He-cooled bolometer detector. Radical densities have been measured in an inductively coupled Gaseous Electronics Conference (GEC) RF Reference Reactor. At frequencies around 100 GHz, large absorption signals can be observed for CHF@sub 3@. Significant amounts of molecular dissociation can be measured when the discharge is ignited. The plasma does not significantly increase the translational temperature, probably due to a large volume of cool gas surrounding the plasma. A 25 times increase in sensitivity would be expected for absorption measurements with frequencies around 500 GHz. Measurements of C@sub x@F@sub y@ and SiF@sub x@ radical densities will also be presented.