Patent ID: 10042271

Abstract:
A projection exposure system (10) for microlithography which includes: a mask holding device (14) holding a mask (18) with mask structures (20) disposed on the mask, a substrate holding device (36) holding a substrate (30), projection optics (26) imaging the mask structures (20) onto the substrate (30) during an exposure process, and a measurement structure (48) disposed in a defined position with respect to a reference element (16) of the projection exposure system (10), which defined position is mechanically uncoupled from the position of the mask holding to device (14). The projection exposure system (10) also includes a detector (52) arranged to record an image of the measurement structure (48) imaged by the projection optics (26). The projection exposure system (10) is configured such that during operation of the projection exposure system (10) the imaging of the mask structures (20) and the imaging of the measurement structure (48) take place at the same time by the projection optics (26. An evaluation device (54) is configured to establish a lateral position of the image of the measurement structure (48) in the area of the detector (52) during the exposure process.