Patent attributes
A plasma processing apparatus performs a stable and accurate matching operation with high reproducibility in a power modulation process of modulating of a high frequency power to be supplied into a processing vessel in a pulse shape. In the plasma processing apparatus, an impedance sensor 96A provided in a matching device performs a dual sampling averaging process on a RF voltage measurement value and an electric current measurement value respectively obtained from a RF voltage detector 100A of a voltage sensor system and a RF electric current detector 108A of an electric current sensor system by sampling-average-value calculating circuits 104A and 112A and by moving-average-value calculating circuits 106A and 114A. Thus, an update speed of a load impedance measurement value outputted from the impedance sensor 96A can be matched well with a driving control speed of a motor in a matching controller.
