| abstract |
A multi-zone carrier head includes a housing; a retaining ring secured to a lower edge of the housing; a backing plate having a plurality of non-concentric pressure zones defined by a plurality of isolated apertures on the backing plate; wherein the backing plate has a wafer side and a non-wafer side, the wafer side facing a backside of a wafer during a CMP operation; and a plurality of pneumatic bladder for independently controlling pressure exerted in the respective non-concentric pressure zones on the backside of the wafer during the CMP operation. |