Set of masks for the projection of structure patterns onto a semiconductor wafer

A set of at least two masks for the projection of structure patterns coordinated with one another by a projection system into the same photosensitive layer of a semiconductor wafer can include a primary mask having an opaque structure element, which is formed at a first position on the first mask. A second mask of the set, for example a trimming mask, which is assigned to the first mask, can have a semitransparent region assigned to the structure element of the first mask. The semitransparent region can be formed at the same position on the second mask as the opaque structure element on the first mask. With the aid of the suitable choice of the transparency of the semitransparent region, it is possible to enable an undesirable resist region to be trimmed away with an enlargement of the process window during the exposure of the semiconductor wafer.