Pupil filtering for a lithographic tool

The present invention relates generally to integrated circuit fabrication equipment. More particularly, the present invention relates to integrated circuit fabrication system for and a method of correcting pupil errors. Even further, the present invention relates to a mask that includes a layer for pupil filtering in a photolithographic camera or stepper unit. A mask or reticle is optimized for use in a lithographic system. The mask or reticle includes a substrate and a pupil filter pattern. The substrate includes an IC pattern representing at least one integrated circuit feature. The pupil filter pattern can enhance the resolution associated with the lithographic system.