PRODUCTION AND CONTROL OF LARGE-DIAMETER SURFACE-WAVE PLASMAS

A planar cylindrical plasma has been produced using small slot antenna s in an aluminum discharge chamber with a cylindrical section with a d iameter of 22 cm. The 2.45 GHz microwave with a power of 0.2-2.0 kW wa s fed through a quartz window into the discharge chamber filled with A r or CF4 at a pressure of a few mTorr to 1 Torr. At relatively high pr essures, interesting made patterns of optical emission and microwave f ield intensity, that is, the m = 3/n = 3 TM mode at 1 Torr and m = 6/n = 2 TM mode at 0.3 Torr, were observed just below a quartz window. Fr om theoretical analysis, these modes are considered to be attributable to the surface waves excited in a large planar cylindrical plasma. Su rface wave plasmas filled with a low-pressure Ar or CF4 gas, say 10 mT orr, were also studied for the etching application. Furthermore, we ha ve carried out time- and space-resolved measurements of plasma paramet ers and microwave field intensity using a pulse-modulated microwave so urce to study the power absorption mechanism in the surface wave plasm a and to demonstrate the pulse-modulated surface wave plasma. Prelimin ary results also show that short-wavelength fluctuations in the electr ic field intensity, which might be considered as mode-converted electr on plasma waves, exist near the quartz window (z < 2 mm) for 5-10 mu s after the microwave pulse was applied. Lastly, a recent result of min imizing a dielectric window is briefly presented.