Rotary union for coupling fluids in a wafer polishing apparatus

Abstract

Device and method are described that reduce the force needed to release a wafer from a wet polishing surface after polishing. Device comprises attachment, such as a wafer carrier, adapted to be mounted to a polishing apparatus to permit attachment surface, configured to mate with two regions of the wafer, to tilt relative to polishing surface. Means for defining adhesive force between attachment surface and one of the two wafer regions, and means for defining adhesive force between attachment surface and other of the two wafer regions which is different than that defined between attachment surface and the one wafer region so as to cause a non-parallel relationship between the one wafer face and polishing surface, are provided. Unbalanced force, such as a vacuum force communicated to a limited region of the surface of the carrier, causes a non-parallel relationship between wafer and polishing pad and facilitates separation and lifting of wafer from polishing surface. Some embodiments include a mechanical lifting force to actively tilt the wafer surface. A rotary union device for use with a polishing apparatus is described that continuously communicates a fluid between a nonrotating fluid source and a fluid chamber enclosed within a rotatable polishing head portion of the polishing apparatus. Independent pressure chambers for controlling polishing pressure and adhesion of the wafer may be provided.