Chemical mechanical polisher cleaning unit

A rotating substrate support for use in a substrate processing system, the substrate support comprising:

• a cylindrical shaped outer hub comprising a first end, a second end, a wall that extends from the first end to the second end, a central opening formed through the wall at the first end and the second end, and a central axis extending through a center of the central opening, wherein
• the wall comprises an inner surface, an outer surface, and a flexible region,
• a circumferential groove formed in the outer surface of the wall and within the flexible region, wherein the circumferential groove comprises a gap that extends in a first direction, and
• the inner surface of the wall forms at least a portion of an inner region of the cylindrical shaped outer hub;
• a first support plate coupled to a first portion of the inner surface of the wall;
• a second support plate coupled to a second portion of the inner surface of the wall;
• and
• an expandable actuator, wherein the expandable actuator is configured to change a size of the gap of the circumferential groove by adjusting a distance in the first direction between the second support plate and the first support plate.