“…To improve process productivity, process monitoring techniques based on plasma diagnostic methods have garnered much attention [ 15 ] since key process parameters such as etching and deposition rates are related to the plasma parameters [ 16 , 17 , 18 , 19 , 20 ]. Plasma diagnostic methods employ an analysis of (i) the current-voltage characteristics of plasma using the Langmuir probe [ 21 , 22 , 23 ], (ii) the response characteristics of plasma to microwaves using resonators (microwave probes) [ 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 ], (iii) the optical emission characteristics of plasma using an optical emission spectrometer (OES) [ 33 , 34 ], and (iv) the voltage and current (VI) waveforms on a powered electrode using VI probes with circuit modeling [ 35 , 36 , 37 ].…”