Mask with programmed defects and method for the fabrication thereof

A mask, and in particular a phase shift product mask, utilizes predetermined defects being produced during the fabrication thereof in the so-called "second layer" process. The defects are identified by markers in their direct vicinity. The markers are quadrangular and indicate, by virtue of their number in combination with their configuration, information about the respectively assigned defect, such as, for example, defect type, defect size, etc.