Patent ID: 7256407

Claim:
A lithographic projection apparatus, comprising: an illumination system configured to form a beam of radiation from radiation provided by an EUV radiation source; a support configured to hold a patterning device which is to be irradiated by the beam to pattern the beam; a substrate table configured to hold a substrate; a projection system configured to image an irradiated portion of the patterning device onto a target portion of the substrate; a reflector assembly placed in the vicinity of the source or an image of the EUV radiation source, the reflector assembly comprising at least an inner and an outer reflector extending in a direction of an optical axis on which the EUV radiation source or an image of the EUV radiation source is located, the inner reflector being closer to the optical axis than the outer reflector, the inner and outer reflectors each having an inner reflective surface and an outer backing layer, the inner reflective surface of the outer reflector facing the backing layer of the inner reflector; a foil trap configured to collect debris from the EUV radiation source, the foil trap being between the EUV radiation source and the reflector assembly; a housing constructed and arranged to contain the reflector assembly and the foil trap, the reflector assembly being connected to the housing via a first wall, and the foil trap being connected to the housing via a second wall; a chamber between the foil trap and the reflector assembly, the chamber being defined by the housing, the first wall, and the second wall; and a pump configured to create a vacuum in the chamber.