A system and method for minimizing critical dimension errors on imaged wafers is described. After imaging and processing one or more wafers, the various critical dimensions are determined across the imaged exposure field and compared with the target critical dimensions to ascertain average critical dimension errors. The critical dimension error distribution across the field is modeled and the necessary exposure dose corrections are calculated to compensate the critical dimension errors. A pellicle is formed with light intensity modifying regions corresponding to the calculated local dose corrections. These regions alter the amount of light which is transmitted from a light source through a semiconductor mask onto the exposure fields of the wafers. As a consequence, the critical dimensions of the printed features are altered as well. The light intensity modifying region may be formed by depositing, such as by sputtering, particles which reflect or absorb light. Alternatively, the light intensity modifying region may be formed with an ink jet printer. Instead, a clear or grey-scaled pellicle may be used, and portions of it may be ablated to alter light transmission in certain areas.