US Patent 7803720 Coating process and equipment for reduced resist consumption

A coating system and method of coating semiconductor wafers is disclosed that is able to maintain a wet condition on the outer portion of the semiconductor wafer to provide ease of spreading for a photo-resist or anti-reflective coating (ARC) that is being dispensed. The system can include a plurality of nozzles on a movable arm. A first nozzle dispenses a pre-wet solvent onto the semiconductor wafer. A second nozzle then dispenses the photo-resist or ARC coating onto the semiconductor wafer. A third nozzle dispenses additional pre-wet solvent onto the outer edge of the semiconductor wafer as the photo-resist or ARC coating is being dispensed. The nozzles dispense solutions onto the semiconductor wafer as it rotates. The system produces semiconductor wafers with few coating defects and uses less photo-resist or ARC coating.