ILLUMINATION SYSTEM, LITHOGRAPHIC APPARATUS AND METHOD OF FORMING AN ILLUMINATION MODE.

摘要

An illumination system of a lithographic apparatus includes a plurality of reflective elements arranged to receive radiation from a radiation source, the reflective elements being movable between different orientations. In the different orientations, the reflective elements direct radiation towards different locations at a reflective component in a pupil plane of the illumination system, thereby forming different illumination modes. Each reflective element is moveable between a first orientation, which directs radiation towards a first location the pupil plane, and a second orientation, which directs radiation towards a second location in the pupil plane. The first orientation and the second orientation of the reflective element are defined by end stops.