System and Method for Projecting a Pattern from a Mask onto a Substrate

A system for projecting a pattern from a mask onto a substrate comprises a radiation source for emitting a light beam in the extreme ultraviolet wavelength range, a mask including absorbent and reflective structures forming the pattern, a collector mirror and an illumination optical system forming a first part of a beam path in order to direct the light beam onto the mask to produce a patterned light beam, a projection optical system including an arrangement of reflective mirrors forming a second part of the beam path in order to focus the reflected light beam from the mask onto the substrate, and an optical element arranged in the beam path and including at least two regions having different degrees of reflection or transmission. First and second of the regions are assigned to respective different first and second positions on the mask and/or collector mirror in accordance with the beam path.