Patent ID: 9188881
Filing Date: 2015-11-17
Classification: G03F

Abstract:
1. A lithographic apparatus comprising: an illumination system configured to condition a beam of extreme ultra-violet radiation; a support configured to hold a reflective patterning device, the reflective patterning device configured to impart a pattern to the beam of extreme ultra-violet radiation; a substrate table configured to hold a substrate; a projection system configured to project the patterned beam of extreme ultra-violet radiation onto a target portion of the substrate; and a masking device configured to control illumination of the reflective patterning device by the beam of extreme ultra-violet radiation, the masking device comprising a masking blade including a masking edge configured to delimit a boundary of an illumination region on the reflective patterning device, and a masking surface having a plurality of facet surfaces, wherein each of the facet surfaces is inclined in a first direction at an angle greater than a maximum angle subtended by radiation that can be captured by the projection system to reflect a portion of the beam of extreme ultra-violet radiation incident on the masking blade such that the reflected extreme ultra-violet radiation is not captured by the projection system.