| CPC G01R 19/2509 (2013.01) [G01R 15/16 (2013.01); G01R 15/18 (2013.01); H01J 37/32183 (2013.01); H01J 37/32899 (2013.01); H01L 21/67161 (2013.01); H01L 21/67253 (2013.01); H01J 2237/24495 (2013.01); H01J 2237/24564 (2013.01)] | 19 Claims |
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1. An apparatus to estimate parameters of a radio frequency (RF) signal coupled to 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 a 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 transform the digital representations of the instantaneous voltage and the digital representations of the instantaneous current into frequency domain representations of a complex voltage corresponding to the RF signal voltage and into frequency domain representations of a complex current corresponding to the RF signal current, the one or more processors additionally configured to combine frequency domain representations of the complex voltage and the complex current to form root mean square (RMS) voltage and RMS current, wherein the frequency domain representations of the complex voltage and the frequency domain representations of the complex current each include a plurality of samples.
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