Abstract: A lithographic apparatus includes a device having a blade selectively insertable into the beam. The device is in a first plane intermediate a second plane conjugate to a plane of the substrate and a third plane conjugate to a pupil plane of the projection system. The blade may include a partially opaque blade and a solid blade or have a predetermined transmissibility pattern. The transmissibility may vary in a second direction perpendicular to the first direction in which the substrate and the patterning device are movable. In an illumination system including a field faceted mirror and a pupil faceted mirror, a reflecting blade is selectively insertable into the beam to reflect a portion of the beam to a beam dump that may be cooled to reduce a heat load. The reflecting element may have a coating that scatters the portion of radiation or changes the phase.

Abstract: An optical element for effecting a desired change in incident radiation at a plane of an illumination system of a lithographic apparatus comprises an array of cells manufactured as a single unit, each cell being arranged to redirect the incident radiation in a predetermined direction. An array of polarizing regions is also provided, each polarizing region being associated with a corresponding cell. Each cell arranged to redirect radiation in a first direction has associated with it a polarizing region ensuring that the redirected radiation has a first polarization, so that all of the radiation redirected in the first direction has the same polarization.

Abstract: A method and apparatus are provided for measuring the apodization of projection optics for use in a lithographic apparatus, the projection optics having an object plane where, in use, a reticle is placed, a pupil plane, and an image plane where, in use, a wafer is placed. The method includes placing one or more Appropriate apertures in said object plane for creating a substantially uniform light distribution, illuminating the or each aperture and measuring the intensity distribution at a plane which is conjugate to the pupil plane in order to calculate the apodization of the projection optics.