Patent ID: 7384149

Claim:
A lithographic projection apparatus, comprising: an illuminator configured to condition a beam of radiation; a support configured to support a patterning device, the patterning device configured to pattern the beam according to a desired pattern; a substrate table configured to hold a substrate; a projection system configured to project the patterned beam onto a target portion of the substrate; and at least one purge gas supply system configured to provide a purge gas to at least part of the lithographic projection apparatus, the at least one purge gas supply system comprising: a purge gas mixture generator comprising a moisturizer configured to add moisture to a purge gas, the purge gas mixture generator configured to generate a purge gas mixture, which gas mixture comprises at least one purge gas and the moisture, wherein the moisturizer comprises a vessel with at least one gas inlet and gas outlet, the at least one gas inlet and gas outlet being connected to each other via a moisturizing connection, such that in case a purge gas flows through the moisturizing connection, the purge gas is fed through a liquid present in the vessel and the purge gas is moisturized; a purge gas mixture outlet connected to the purge gas mixture generator configured to supply the purge gas mixture to the at least part of the lithographic projection apparatus; and a dry gas inlet configured to mix a non-moisturized purge gas with the moisturized purge gas fed through the liquid to thereby obtain the purge gas mixture.