LITHOGRAPHIC PROJECTION APPARATUS, GAS PURGING METHOD, DEVICE MANUFACTURING METHOD AND PURGE GAS SUPPLY SYSTEM

摘要

A lithographic projection apparatus (1) comprising: a support structure for supporting patterning means, the patterning means serving to pattern the projection beam according to a desired patter. The apparatus has a substrate table (WT) for holding a substrate, a projection system (PL) for projecting the patterned beam onto a target portion of the substrate. The apparatus also has a purge gas supply system (100) for providing a purge gas near a surface of a component of the lithographic projection apparatus. The purge gas supply system comprises a purge gas mixture generator (120). The purge gas mixture generator (120) is arranged for generating a purge gas mixture which comprises at least one purging gas and a moisture. The purge gas mixture generator (120) has a moisturiser device arranged for adding the moisture to the purge gas and a purge gas mixture outlet (130-133) connected to the purge gas mixture generator for supplying the purge gas mixture near the surface.