Verfahren zur Fokussierung bei der Abbildung strukturierter Oberflächen von scheibenförmigen Objekten

摘要

The invention relates to a method for focusing during imaging of structured surfaces of disc-shaped objects in order to provide images required for image processing, to enhance error detection accuracy and to reduce the pseudo error rate. The distance arising as a result of controlled adjustment between a support plane acting as a base for the objects and a reference plane is corrected by an unadjusted pre-regulation control value at least for one part of the surface. The inventive method can be chiefly used in process control of semiconductor wafer manufacturing.