Abstract: A lithographic projection apparatus is disclosed. The apparatus includes a radiation system for providing a beam of radiation, and a support structure for supporting a patterning device. The patterning device serves to pattern the beam of radiation according to a desired pattern. The apparatus also includes a substrate support for supporting a substrate, a projection system for projecting the patterned beam of radiation onto a target portion of the substrate, and a purge gas supply system. The purge gas supply system includes a purge gas mixture generator that includes a moisturizer that is arranged for adding moisture to a purge gas to generate a purge gas mixture, and a purge gas mixture outlet connected to the purge gas mixture generator for supplying the purge gas mixture to at least part of the lithographic projection apparatus.

Abstract: A lithographic projection apparatus includes a support configured to support a patterning device, the patterning device configure to pattern the projection beam according to a desired patter. The apparatus has a substrate table configure to hold a substrate, a projection system configured to project the patterned beam onto a target portion of the substrate. The apparatus also has a purge gas supply system configured to provide a purge gas near a surface of a component of the lithographic projection apparatus. The purge gas supply system includes a purge gas mixture generator configured to generate a purge gas mixture which includes at least one purging gas and a moisture. The purge gas mixture generator has a moisturizer configured to add the moisture to the purge gas and a purge gas mixture outlet connected to the purge gas mixture generator configured to supply the purge gas mixture near the surface.