Patent attributes
Methods and apparatus are provided to provide a substantially uniform layer thickness above a wafer contour as the wafer rotates and is traversed past a pre-planarization tool. The tool has a shank defining an axis of rotation, and a planarization member coupled to the shank has a hook-shaped section supporting a pre-planarization surface spaced by an at-rest-distance from the axis of during an at-rest condition of the shank. The hook-shaped section has a modulus of elasticity selected so that upon rotation, the hook-shaped section flexes and moves the pre-planarization surface to rotation-distances spaced from the axis in response to a velocity of rotation of the hook-shaped section around the axis in a range of velocities. As the tool rotates, metrology intermittently directly senses the layer thickness and controls the velocity of rotation so the rotation-distances have values in excess of a value of the at-rest-distance.
