Real-time edge encroachment control for wafer bevel

A method, comprising:

• generating a plasma for bevel edge processing of a wafer when present, the plasma being generated using radio frequency (RF) power delivered to a main electrode supporting the wafer, the RF power being generated by a main RF generator;
• providing an upper process exclusion zone ring that defines a physical boundary that establishes an amount of encroachment of the plasma toward a center of the wafer from a bevel edge process region;
• applying RF power to an electrode in the upper process exclusion zone ring, the RF power being applied to the electrode in the upper process exclusion zone ring being generated by a secondary RF generator that is separate from the main RF generator;
• and
• controlling the RF power applied to the electrode in the upper process exclusion zone ring to provide an additional barrier to plasma to reduce the amount of encroachment of the plasma toward the center of the wafer from the bevel edge process region, such that an amount of a periphery of the wafer to be bevel edge processed with the generated plasma is reduced.

A plasma processing system, comprising:

• a chamber;
• a bottom electrode disposed in the chamber;
• a lower extended electrode disposed around the bottom electrode;
• an upper ceramic plate disposed in the chamber, the upper ceramic plate being disposed above the bottom electrode in an opposing relationship with the bottom electrode, such that a separation gap is defined between a top surface of a wafer, when present over the bottom electrode, and the upper ceramic plate, wherein the separation gap is less than about 2.0 mm;
• an upper extended electrode disposed around the upper ceramic plate;
• a lower process exclusion zone ring situated between the lower extended electrode and the bottom electrode, the lower process exclusion zone ring being comprised of an insulative material that electrically separates the bottom electrode from the lower extended electrode;
• an upper process exclusion zone ring situated between the upper extended electrode and the upper ceramic plate, the upper process exclusion zone ring having a radio frequency (RF) electrode ring embedded therein, and the upper process exclusion zone ring being comprised of an insulative material that electrically separates the embedded RF electrode ring from the upper extended electrode;
• an RF generator for generating RF power for the bottom electrode, the RF generator for generating the RF power for the bottom electrode having a matching circuit associated therewith;
• an encroachment power module, the encroachment power module including an RF generator for generating RF power for the RF electrode ring embedded in the upper process exclusion zone ring and a matching circuit associated with the RF generator for generating the RF power for the embedded RF electrode ring;
• and
• a controller for transmitting processing instructions, the processing instructions including general etch settings and encroachment control settings.