Patent ID: 6755726
Filing Date: 2004-06-29
Classification: B24B

Abstract:
An improvement CMP polishing head having a base, a retaining ring secured to the base defining a pocket area beneath the base, and a lower assembly floating within the pocket area by way of a diaphragm seal, the lower assembly having a disk-shaped plate having a plurality of apertures distributed in a center region of the plate, a clamp ring used to secure the diaphragm seal along a rim region of the plate, and a floating knife-edge mechanism, characterized in that:the floating knife-edge mechanism disposed through an opening between the rim region and the center region of the plate, the floating knife-edge mechanism including an independently movable member relative to the plate movable between a first retracted position wherein the plate presents a substantially flat bottom surface during a CMP operation, and a second extended position providing a downwardly projected lip portion engaging the wafer so as to form a seal for improved vacuum-chucking.