METHOD FOR CORRECTING ERRORS IN PHOTOLITHOGRAPHIC MASKS WHILE AVOIDING DAMAGE TO REAR-SIDE COATINGS

The present invention relates to a method for correcting placement errors in a photolithographic mask comprising a substrate and structures formed on the substrate, the method involving at least one local density change, preferably a plurality of local density changes, each of which defines a pixel, being introduced into the substrate by use of a laser beam in order to correct placement errors of the structures, wherein in an examination step, an incidence surface of the mask, via which the laser beam radiates into the substrate, is examined for contaminations and, in regions in which a contamination of the incidence surface has been ascertained in the examination step, no laser irradiation or a laser irradiation with at least one changed laser beam parameter takes place, the laser beam parameter(s) being changed such that no damage to the incidence surface or near-surface regions occurs in the case of an interaction between laser beam and contamination.