Carl Zeiss Smt Gmbh

Michael Jöst

Michael Budach

Ralf Schönberger

The invention relates to a method for automated determination of a reference point of an alignment mark on a substrate of a photolithographic mask, which method comprises the following steps: (a) performing a first line scan within a start region of the substrate in a first direction on a surface of the substrate, the alignment mark being arranged within the start region, for locating a first element of the alignment mark; (b) performing a second line scan within the start region in at least a second direction, which intersects the first direction, on the surface of the substrate for locating a second element of the alignment mark; (c) estimating the reference point of the alignment mark from the located first element and the located second element of the alignment mark; and (d) imaging a target region around the estimated reference point of the alignment mark in order to determine the reference point of the alignment mark, with the imaging being carried out at a higher resolution than the performance of the line scans in steps (a) and (b).

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Gross-Gerau, Germany

Michael Jöst