Patent ID: 7476491
Filing Date: 2009-01-13
Classification: G03F

Abstract:
1. A lithographic apparatus comprising: an illumination system for providing a beam of radiation; a support structure for supporting a patterning device, the patterning device serving to impart the beam of radiation with a pattern in its cross-section; a substrate table for holding a substrate; a projection system for projecting the patterned beam onto a target portion of the substrate; and a gas supply system for supplying a purge gas comprising oxygen to a plurality of spaces in said apparatus, the gas supply system being arranged so that the purge gas being supplied to each of the plurality of spaces is a premixed purge gas mixture composed by the gas supply system for each of the plurality of spaces on the basis of a predetermined relationship that relates a desired amount of oxygen in the premixed purge gas mixture to the respective space to which that premixed purge gas mixture is supplied.