US Patent 11745306 Polishing apparatus and method of controlling inclination of stationary ring

A polishing apparatus includes a rotatable head body having a pressing surface, a retainer ring configured to press a polishing surface while rotating together with the head body, a stationary ring, local load applying devices configured to apply a local load to the stationary ring, and a controller. The local load applying devices include a first pressing member and a second pressing member connected to the stationary ring. The first pressing member is disposed in the upstream side of the retainer ring in the traveling direction of the polishing surface, and the second pressing member is disposed in the downstream side. The controller calculates the inclination angle of the stationary ring based on a measured value of the height of at least one of the first pressing member and the second pressing member.