Learning based tuning in a radio frequency plasma processing chamber

A plasma processing chamber comprising:

• a match comprising a tuning circuit that comprises a first capacitor and a second capacitor;
• an RF generator having an RF power output and coupled to a first electrode within the plasma processing chamber;
• a controller;
• and
• a memory for storing a program to be executed in the controller, the program comprising instructions when executed cause the following:
• tuning a first capacitor and a second capacitor of a tuning circuit to match a first impedance corresponding to a first stage of a waveform, while a frequency of a radio frequency (RF) generator is preset to a first frequency;
• tuning a third capacitor of the tuning circuit and the frequency of the RF generator to match a second impedance corresponding to a second stage of the waveform, wherein the frequency of the RF generator is tuned to a second frequency, and the first stage and the second stage are different stages of the waveform;
• recording setting values of the first frequency and the second frequency that match the first impedance and second impedance, respectively;
• and
• switching between the first frequency and the second frequency to match the different impedances at the different stages of the waveform using the settings of the first capacitor, the second capacitor and the third capacitor set by the tuning of first capacitor and the second capacitor to match the first impedance and the tuning of third capacitor to match the second impedance.

A method of processing a substrate in a plasma processing system, comprising:

• tuning a first capacitor and a second capacitor of a tuning circuit to match a first impedance corresponding to a first stage of a waveform, while a frequency of a radio frequency (RF) generator is preset to a first frequency;
• tuning the frequency of the RF generator to match a second impedance corresponding to a second stage of the waveform, wherein the frequency of the RF generator is tuned to a second frequency, and the first stage and the second stage are different stages of the waveform;
• recording setting values of the first frequency and the second frequency that match the first impedance and second impedance, respectively;
• and
• switching between the first frequency and the second frequency to match the different impedances at the different stages of the waveform using the settings of the first capacitor and the second capacitor set by the tuning of first capacitor and the second capacitor to match the first impedance.