Method for determination and/or optimization of focus setting in optical arrangement i.e. measuring device, for measurement of structures of photomasks, involves determining parameter for determination of sharpness of image in image regions

摘要

The method involves producing an image by an optical arrangement (1). A parameter for determination of sharpness of the image is determined for the produced image. The image is produced with different image regions in which focal positions (5-8) are different. The parameter for determination of the sharpness of the image is determined in the image regions. The different focal positions in the image regions are produced by a stage plate (4) i.e. focus manipulator. The stage plate in a field plane or in proximity to the field plane is arranged in the optical arrangement. An independent claim is also included for an optical arrangement for imaging of an object.