AVS 50th International Symposium
    Plasma Science and Technology Wednesday Sessions
       Session PS2-WeA

Paper PS2-WeA4
Ultraviolet Emission Spectroscopy and Absorption Spectroscopy of CF@sub 2@ Radical in Chemical Vaporization Machining (CVM) Plasma Generated with High Speed Rotating Cylindrical Electrode

Wednesday, November 5, 2003, 3:00 pm, Room 315

Session: Atmospheric Plasmas & Micro Discharges
Presenter: Y. Oshikane, Osaka University, Japan
Authors: Y. Oshikane, Osaka University, Japan
S. Sato, Osaka University, Japan
A. Nagao, Osaka University, Japan
K. Yamamura, Osaka University, Japan
K. Endo, Osaka University, Japan
Y. Mori, Osaka University, Japan
Correspondent: Click to Email
Optical emission spectroscopy and broad-band absorption spectroscopy in UV region have been applied for determining CF@sub 2@ radical density in the chemical vaporization machining (CVM) plasma, which is generated in below 1 mm gap between the side of rotating cylindrical electrode (alumina) and flat substrate (silicon, quartz) by VHF at 150 MHz. By using a grating spectrograph consists of imaging aspheric mirrors coupled with cooled CCD camera, a spatially resolved UV spectrum has been recorded for CF and CF@sub 2@ radicals. Relative changes in CF@sub 2@ density in He/CF@sub 4@/O@sub 2@ plasma were monitored. The experiments cover a wide range of pressure, composition, rotation speed, and power deposition conditions (10@super 3@-10@super 5@ Pa, 0.01-1% CF@sub 2@, 0.01-1% O@sub 2@, 0-2000 rpm, 15-100 W). Increasing the pressure from 10@super 3@ to 10@super 5@ Pa showed large changes in CF@sub 2@ band spectrum. Both emission and absorption spectrum of a 10@super 3@ Pa He/CF@sub 4@/O@sub 2@ plasma showed the A(0,v,0)-X(0,0,0) (v=0 to 13) transition of the CF@sub 2@ molecule from 230 to 270 nm. But the spectrum shifts to longer wavelengths and showed the A(0,0,0)-X(0,v,0) (v=0 to 10) transition spectrum from 260 to 340 nm at atmospheric pressure. The spatially resolved absorption spectrum showed the absorption peaks near the side of electrode and substrate surface.