An electrical diagnostic method for double probe applicable to processing plasma

Plasma parameters were measured by applying AC voltage to the double probe. The double probe has the advantage of measuring plasma parameters regardless of the condition of the wall of the processing chamber. When the area of the two probes is different, the plasma parameters were measured considering the area of the probe, and it agrees well with the results measured by the conventional method. Since the electron temperature and ion density are corrected using the phase difference between the applied voltage and the measured current, accurate measurement is possible even when a polymer is deposited on the probe tips. In various RF discharge conditions, the electron temperature and ion density of the proposed method and the conventional method were matched in the case of different areas and the case of deposition. Additionally, when measuring plasma parameters with an asymmetric double probe, the measurable density range is extended.