US Patent 11571786 Consumable part monitoring in chemical mechanical polisher

A polishing apparatus includes a polishing station to hold a polishing pad, a carrier head to hold a substrate in contact with a polishing pad at the polishing station, a camera positioned to capture an image of a lower surface of a consumable part when the consumable part moves away from the polishing pad, and a controller configured to perform an image processing algorithm on the image to determine whether the consumable part is damaged. The consumable part can be a retaining ring on a carrier head, or a conditioner disk on a conditioner head.