Abstract: The purpose of the present invention is to provide a carrier mechanism, that polishes the wafer equally across the wafer surface by circumventing the problems caused by “pad rebound” or “waving phenomenon” during polishing. In doing this, pressure against the pad at the edge of the wafer will be equal to that at the center resulting in uniform pressure on the wafer during polishing and even planarization of thin film semiconductor material. One embodiment of the present invention uses a wider extension ring causing the pressure stress concentration point to occur just inside the outer edge of the extension ring and away from the wafer. This allows for constant pressure application to the surface of the wafer and results in uniform material removal across the wafer surface. A second embodiment of the present invention uses a wider extension ring having a slurry channel and a plurality of passageways.

Abstract: Double or multiple unit polishing heads are used thereby negating the negative effects that irregularities in the surface of the polishing pad have on the polishing results obtained. Adjacent double or multiple unit polishing heads rotate in opposite directions thereby eliminating the effects of microscopic directions in the surface of the polishing pads.