RF signal parameter measurement in an integrated circuit fabrication chamber

An apparatus adapted to estimate radio frequency (RF) power coupled to a station of an integrated circuit fabrication chamber, comprising:

• a voltage sensor configured to provide an indication of a voltage of the RF signal;
• a current sensor configured to provide an indication of the current conducted by the RF signal;
• an analog-to-digital conversion module coupled to an output port of the voltage sensor and to an output port of the current sensor, the analog-to-digital converter configured to provide digital representations of an instantaneous voltage and an instantaneous current of the RF signal;
• and
• one or more processors configured to:
• obtain the digital representations of the instantaneous voltage of the RF signal and the digital representations of the instantaneous current conducted by the RF signal;
• transform the obtained digital representations of the instantaneous voltage of the RF signal and the instantaneous current of the RF signal into a frequency domain representation of a complex voltage corresponding to the voltage of the RF signal and into a frequency domain representation of a complex current corresponding to the current conducted by the RF signal;
• and
• combine the complex voltage of the RF signal and the complex current of the RF signal to form root mean square (RMS) voltage and RMS current, wherein the frequency domain representation of the complex voltage and the frequency domain representation of the complex current each include a plurality of samples.