Patent ID: 11881381
Assignee: LAM RESEARCH CORPORATION
Field: Measurement (Instruments)
Classification: CPC H  C  G | IPC C  G  H

Claim 9:
10. The method of claim 3, wherein:
aa) includes generating an alternating voltage (Vin) as the first signal at the first frequency (ω) using an oscillator, an output of the oscillator being coupled to a reference capacitor (Cref), and connecting the reference capacitor to be electrically parallel with the capacitor when the alternating voltage charges the reference capacitor to a reference voltage (Vref);
cc) includes measuring as the measured filtered signal a voltage corresponding to a charge in the electrically parallel combination of the reference capacitor and the capacitor at the first frequency (ω); and
dd) includes converting the measured filtered signal to the measured capacitance value (C) based in part on C=Cref (Vref/Vout−1).