EXPERIMENTAL STUDY OF SPATIAL NON-UNIFORMITIES IN A DUAL FREQUENCY CAPACITIVELY COUPLED PLASMA

Radial non-uniformities of dual frequency capacitively coupled argon plasma were experimentally studied, using an optical emission spectroscopy probe, for different discharge pressures, discharge gaps, and frequencies and powers of the low frequency source. It was shown that the plasma emission profiles strongly depend on the working gas pressure and the lower frequency (LF) power. With the increasing LF power the emission profiles changed from a bell-shaped distribution at low LF power to a double-peak distribution at high LF power.