Method and apparatus for within-wafer profile localized tuning

A system for thickness profile tuning of a wafer, comprising:

• a rotating vacuum stage configured to hold a wafer, the wafer comprising an upwardly facing surface film with an incoming film thickness profile;
• an edge ring surrounding the vacuum stage and forming an alcove for the wafer;
• a rotating head;
• a pad attached to the rotating head, the pad comprising a downwardly facing front side surface, the rotating head configured to sweep the pad along a path, a surface area of the head being less than a surface area of the wafer;
• a controller;
• and
• a computer-readable memory in communication with the controller and having stored thereon computer executable instructions to cause the controller to be configured to:
• remove at least a portion of the surface film of the wafer via a plurality of steps, each of the steps comprising:
• bringing the surface film of the wafer and the front side down surface of the pad into contact with each other, and
• sweeping the head along the path comprising moving the pad across a boundary between the wafer and the edge ring, wherein the edge ring is positioned around the wafer during the sweeping such that a top surface of the edge ring is approximately aligned with the surface film of the wafer to avoid any shock when the pad moves across the boundary and to prevent removal drops at the edge of the wafer, and
• adjust one or more parameters for each of the removal steps to affect an amount of film thickness removed,
• wherein the one or more parameters are adjusted based on the incoming thickness profile and a criteria for the within-wafer-uniformity,
• wherein at least one of the removal steps comprises a rough tuning step including:
• determining a specific zone of the incoming film thickness profile in which at least one protrusive portion is confined, and
• oscillation scanning the head along the specific zone of the path to flatten the at least one protrusive portion in the incoming film thickness profile, the oscillation scanning including moving the head back and forth within the specific zone.