A method for the reproducible determination of the positions of structures (3) on a mask (2) is disclosed. A pellicle frame (30) is firmly attached to the mask (2). A theoretical model of the bending of the mask (2) with the firmly attached pellicle frame (30) is calculated, wherein material properties of the mask (2), of the pellicle frame (30), and of the attaching means between the pellicle frame (30) and the mask (2) are taken into account in the calculation of the bending of the mask (2). For the calculation of the bending of the mask (2) its contact with three support points is considered. The positions of the structures (3) on the mask (2) are measured with a metrology tool (1). The measured positions of each structure are corrected with the theoretical model of the bending of the mask at the position of the respectively measured structure.