Vacuum-grooved membrane wafer polishing workholder

摘要

Hard-material, flat-surfaced workpieces such as semiconductor wafers or sapphire disks are attached with vacuum to the flexible elastomeric membrane of a rotatable 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 where vacuum supplied to the grooves firmly attach the rigid-material silicon wafer in flat-surfaced contact with the membrane. The attached wafer seals the vacuum grooves. A flexible thin metal annular membrane support disk is attached to the membrane within an abrading-pressure chamber where attached drive pins engage matching holes in the wafer carrier provide rotational torque to the wafer and restrain it laterally against abrading forces. Wafer polishing pressure is applied uniformly over the wafer surface. The rotating wafer peripheral edge does not contact a rigid retaining ring during a wafer polishing procedure.

主权项

1. An abrasive polishing wafer carrier apparatus comprising:
a) a movable carrier housing attached to a rotatable shaft having a rotatable shaft axis of rotation; b) a flexible membrane attached to the movable carrier housing, the flexible membrane having a top surface, a nominally-circular and nominally-flat bottom surface, a flexible membrane thickness, and a rotation center nominally-concentric with the movable carrier housing rotatable axis of rotation, wherein the flexible membrane nominally-flat bottom surface has recessed vacuum grooves therein; c) a vacuum source fluid-coupled to the flexible membrane recessed vacuum grooves; and d) a pressure source fluid-coupled to a sealed pressure chamber formed by the flexible membrane and the movable carrier housing; and e) a flexible membrane flexible annular support ring attached to the flexible membrane wherein the flexible annular support ring has an annular width and a flexible support ring thickness that is positioned within the sealed pressure chamber.