Resistance and capacitance measurements of the films deposited on a planar Langmuir probe

The beneficial use of DC-pulsing instead of RF for biasing a capacitively coupled planar Langmuir probe mounted in industrial CCP etcher is demonstrated. The ion flux is determined from the discharging of a DC-biased capacitor for Ar, O$_{2}$, and C$_{2}$H$_{4}$-based plasmas taking into account the RC constant of the films grown on the probe. A comparison is made between the clean probe after Ar sputter-cleaning and the probe coated with a polymer film. A new fitting procedure is proposed including both the capacitance and resistance of the film. The experimental validation is done with a C$_{2}$H$_{4}$-based polymer film, which resistance and capacitance are measured. Finally, it is shown that, together with the measurement of intrinsic plasma parameters like T$_{e}$ and ion flux, one can monitor deposition on the chamber walls that can possibly be extrapolated to the etched wafer.