Abstract: A tool for modifying substrate support elements of a substrate holder, the substrate support elements having support surfaces for supporting a substrate, the tool includes a main body having a main body surface, and multiple protrusions from the main body surface, the multiple protrusions having distal ends configured to contact the support surfaces to modify the substrate support elements. Furthermore, a lithographic apparatus and a method comprising such a tool are provided.

Abstract: A lithographic apparatus according to one embodiment includes an alignment system for aligning a substrate. The alignment system comprises an illuminator system configured to illuminate an alignment mark on the substrate with an illumination spot, the alignment mark comprising a plurality of lines and spaces. The system also includes a combiner system configured to transfer two images of the illuminated alignment mark without spatial filtering of the images, rotate the images 180° relatively to each other, and combine the two images; and a detection system configured to detect an alignment signal from the combined images and to determine a unique alignment position by selecting a specific one of extreme values in the detected alignment signal.