Method and apparatus for controlled polishing

An apparatus for controlling a polishing process, in particular for detecting an end point of the polishing process, comprising a rotating or orbiting platen with a pad, a rotating head that supports an object to be treated, e.g., a semiconductor wafer, and performs radial movements with respect to the platen, and a polishing process control system comprising a plurality of groups of various sensing devices for detecting an end point of the process. In the illustrated embodiment one group of the sensing devices is a group of high-frequency acoustic emission sensors built on various levels into components of the rotating head. Another group of sensing devices is represented by force/torque sensors connected with various elements of the rotating head and the platen, respectively, and intended for direct measurement of compression force and friction response (force or torque) between the head and the platen and a coefficient of friction between the wafer and the polishing pad. All groups of sensors work simultaneously and their measurement data is processed and analyzed by a control unit for obtaining accurate and reliable results.