https://publica.fraunhofer.de/entities/patent/c27ce05b-10cd-409d-8303-670cdc14a557
Verfahren und Sensoreinheit zur Abstandsmessung in einer lithografischen Vorrichtung und...
The method involves deflecting light (1) of an illumination device around a defined angle by using a diffraction structure (3) located on a photomask (5) or on...
verfahrenundzurabstandsmessungeiner