Electrical characterisation of an industrial capacitively coupled plasma processing chamber for actinometry studies in Ar/O$_{2}$/SF$_{6}$ gas mixtures with global model comparisons

Actinometry is an optical emission technique for estimating concentrations of radical particle densities in plasmas. This technique is based on normalised emission intensity of a radical to that of an inert gas giving a ratio of concentrations. To determine radical concentrations, electrical characteristics such as electron density, n$_{e}$, electron temperature, T$_{e}$ and electron energy distribution function (EEDF) must be known. A number of electrical diagnostics are used to measure these parameters which are subsequently used in calculation of radical particle densities of a given reactive gas. An investigation of the pressure and power effect on the electron and ion energy distribution functions (IEDF) was carried out for a number of discharge gases including Ar, O$_{2}$ and SF$_{6}$ in a capacitively coupled plasma reactor. A hairpin probe is used to measure the electron density in the centre of the discharge and a Langmuir probe determines the EEDF. In addition, the EEDF and IEDF at the surface of the electrode are investigated using a retarding field energy analyser (RFEA) for comparison. The data is compared with a global model of the discharge and the results presented.