Detection device for detecting a structure on an area portion of a lithography mask, and apparatus comprising a detection device of this type

A method for operating a detection device for detecting a structure on an area portion of a lithography mask or for operating an apparatus for detecting a structure on an area portion of a lithography mask,

• wherein the detection device comprises:
• a first spatially resolving detector, embodied as a high-intensity (HI) detector, arranged in an HI beam path of detection light which emanates from the mask area portion, and
• a further spatially resolving detector, arranged separately from the first spatially resolving detector embodied as a low-intensity (LI) detector, arranged in an LI beam path of the detection light,
• wherein the HI beam path on the one hand and the LI beam path on the other hand are embodied such that the HI detector is illuminated with a detection light intensity that is at least twice the magnitude of the detection light intensity with which the LI detector is illuminated,
• wherein the two spatially resolving detectors are embodied for simultaneously detecting the detection light, and the spatially resolving detectors are arranged such that a reflection at the HI detector is part of the LI beam path,
• wherein the apparatus comprises:
• the detection device,
• a light source for the detection light, and
• a mask holder for mounting the lithography mask,
• wherein the method comprises the following steps:
• recording images by simultaneously detecting the detection light by use of the detectors of the apparatus, and
• combining the recorded images to form an overall image.