Active far edge plasma tunability

A method for tuning a plasma in a chamber, comprising:

• applying a first radio frequency power to a central electrode embedded in a substrate support;
• applying a second radio frequency power to an annular electrode embedded in the substrate support at a location different than the central electrode, wherein the annular electrode circumferentially surrounds the central electrode;
• monitoring parameters of the first and second radio frequency power;
• and
• adjusting both of the first and second radio frequency powers based on the monitored parameters.

A method for tuning a plasma in a chamber, comprising:

• applying a first impedance, a first voltage, or a combination of the first impedance and voltage to a central electrode embedded in a substrate support;
• applying a second impedance, a second voltage, or a combination of the second impedance and voltage to an annular electrode embedded in the substrate support at a location different than the central electrode, wherein the annular electrode circumferentially surrounds the central electrode;
• monitoring one or more parameters of the first impedance, the second impedance, the first voltage, the second voltage, or any combination thereof;
• and
• adjusting one or more of the first impedance, the second impedance, the first voltage, the second voltage, or any combination thereof based on the monitored parameters.