Patent attributes
Hard-material, flat-surfaced workpieces such as semiconductor wafers or sapphire disks are attached with vacuum to the flexible elastomeric membrane of a wafer carrier that allows one surface of the workpiece to be in conformal abrading contact with a moving flat-surfaced abrasive. The elastomeric membrane external wafer attachment surface has a pattern of recessed vacuum grooves and vacuum is supplied to the grooves to firmly attach the rigid-material silicon wafer in flat-surfaced contact with the membrane. The attached wafer seals the vacuum grooves and also provides lateral stiffness to the center portion of the membrane. An outer annular extension of the flexible elastomer membrane maintains the wafer at its original membrane-centered location when abrading forces are applied to the rotating wafer. The rotating wafer peripheral edge does not contact a rigid retaining ring during a wafer polishing procedure. Fixed-abrasive disks or raised-island abrasive disks are attached to a rotatable flat-surfaced platen.
