Chemical mechanical polishing with friction-based control

摘要

A chemical mechanical polishing apparatus (20)has a polishing surface, a carrier head (34) to press a substrate (10)against the polishing surface (24) with a controllable pressure, a motor (26) to generate relative motion between the polishing surface (24) and the carrier head (34) at a velocity, and a controller (42). The controller is configured to vary at least one of the pressure and velocity in response to a signal that depends on the friction between the substrate and the polishing surface to maintain a constant torque, frictional force, or coefficient of friction.