Patent ID: 7563547

Claim:
A photomask comprising: a substrate transparent to exposure light emitted from a light source of optical exposure equipment and having a front side and a back side; a light-shielding film extending along the front side of the substrate and defining a mask pattern comprising a pattern of transmission regions through which the photomask transmits exposure light, the transmission regions being dedicated for use in forming a pattern on a substrate during a photolithography process in which the substrate is irradiated with the exposure light such that an image corresponding to the pattern of transmission regions is transmitted by the photomask; and an auxiliary pattern different from the mask pattern on the front side of the substrate, the auxiliary pattern comprising at least one recess in the substrate, each said at least one recess being located within one of the transmission regions so as to decrease the intensity of the light passing through the substrate, and each said at least one recess occupying a smaller area than the transmission region in which it is located.