Solid-state impedance matching systems including a hybrid tuning network with a switchable coarse tuning network and a varactor fine tuning network

A method comprising:

• determining a distortion quantity, wherein the distortion quantity is an indication of an amount of reflected power provided from a radio frequency (RF) generator to a plasma processing chamber;
• based on the distortion quantity, determining a gain value for an electronic variable capacitance, wherein the electronic variable capacitance is a shunt capacitance or a series capacitance of an impedance matching network connected between the RF generator and the plasma processing chamber, wherein the electronic variable capacitance comprises a switchable circuit and a varactor, and wherein the varactor is connected in parallel with the switchable circuit;
• and
• during a direct convergence mode,
• adjusting a first direct current (DC) bias voltage from an initial DC bias voltage directly to a first target voltage, and
• supplying the first target voltage to the switchable circuit or the varactor.

A controller comprising:

• an adjustment module configured to determine a distortion quantity corresponding to a transfer of RF power from a RF generator to an impedance matching network of a plasma processing system;
• a control circuit configured to (i) generate a control signal based on the distortion quantity, and (ii) output the control signal to a driver circuit to provide a first direct current (DC) bias voltage to and set a capacitance of a switchable circuit of a hybrid tuning network in the impedance matching network;
• and
• a bias circuit configured to (i) generate a second DC bias voltage based on the distortion quantity, and (ii) output the second DC bias voltage to a varactor of the hybrid tuning network,
• wherein the adjustment module is configured to
• receive a first feedback signal based on a condition of the switchable circuit,
• receive a second feedback signal based on a condition of the varactor,
• adjust the control signal based on the first feedback signal, and
• adjust the second DC bias voltage based on the second feedback signal.

A electronic variable capacitance comprising:

• a first diode connected at a first end to a direct current (DC) bias voltage terminal;
• and
• a second diode connected to a second end of the first diode and in a back-to-back varactor configuration with the first diode,
• wherein
• the second diode is configured to receive a radio frequency (RF) signal from a RF generator of a plasma processing system,
• the DC bias voltage is provided across the first diode and the second diode,
• the second diode, based on the DC bias voltage, is forward biased to a voltage that is less than a built-in potential of the second diode,
• the first diode, based on the DC bias voltage, is reversed biased while the second diode is forward biased, such that the first diode and the second diode perform as a variable capacitor while in an OFF state, and
• the first diode outputs a RF output signal at the first end of the first diode.