Patent ID: 7307263

Claim:
A lithographic apparatus comprising: a radiation system comprising a source for producing a radiation beam, a contaminant trap arranged in a path of the radiation beam, and an illumination system configured to condition the radiation beam produced by said source; a support for supporting a patterning device, the patterning device serving to impart the conditioned radiation beam with a pattern in its cross-section; a substrate table for holding a substrate; and a projection system for projecting the patterned radiation beam onto a target portion of the substrate, said contaminant trap comprising a plurality of foils that define channels that are arranged substantially parallel to the direction of propagation of said radiation beam, wherein the contaminant trap is provided with a gas supply system that is arranged to inject gas into at least one of the channels of the contaminant trap, and wherein at least one of the foils comprises at least one opening for the gas injection.