APPARATUS FOR MEASURING PHOTO MASK AND METHOD FOR MEASURING CD OF PHOTO MASK USING THE SAME, APPARATUS AND METHOD OF CORRECTING THE PHOTO MASK USING THE CD AND METHOD OF MANUFACTURING THE PHOTO MASK

摘要

An approach to correcting non-uniformity of critical dimension (CD) in a semiconductor wafer includes measuring 0SUPth/SUP-order light transmitted through or reflected from a photomask in a plurality of regions of the photomask. The photomask is altered to equalize the 0SUPth/SUP-order light from the photomask such that the wafer CD is uniform. The photomask can be altered such as by forming a phase grating on the back side of the photomask or by introducing shadowing elements into the photomask to alter the transmittance of the photomask.