Retaining ring with active edge-profile control by piezoelectric actuator/sensors

摘要

A polishing head for holding a wafer during a polishing process without the edge-effect or the edge peeling defect and a method for improving edge profile on a wafer during a polishing process are described. The polishing head is constructed by a carrier head, a retaining ring, and at least three piezoelectric actuator/sensors mounted in-between a recessed peripheral edge portion of the carrier head and a top surface of the retaining ring.