Abstract: Provided is an impedance matching network having: an amplitude-adjusting variable capacitor and a phase-adjusting variable capacitor that are positioned between an input terminal and an output terminal, matching being achieved by adjustment of values of the variable capacitors; a first capacitor connected in series to one of the variable capacitors; a first switch connected in parallel to the one of the variable capacitors; and a unit operable to a) keep the first switch to an ON state while the input terminal does not receive RF power, and b) bring the first switch to an OFF state immediately after an initial start-up of a load connected to the output terminal after the input terminal has started to receive RF power.

Abstract: A plasma processing apparatus comprises: an RF generator operable to output RF power; an impedance matching network operable to receive the RF power; a plasma chamber operable to receive an output from the impedance matching network; a storing unit operable to store information relating to an S parameter of the impedance matching network; and a control unit operable to control an operating condition for the plasma chamber, based on the information relating to the S parameter.