Patent ID: 7961292

Claim:
A photolithography system, comprising: an illumination system configured to direct illumination radiation towards a semiconductor wafer; and an imaging mask interposed between the illumination system and the semiconductor wafer that is formed on an optically transmissive substrate that is spaced apart from the wafer, the mask further including at least one sub-resolution assist device comprising: a first optical attenuation region and a spaced-apart second optical attenuation region; and an optically transmissive phase adjustment region extending through a space defined between the first optical attenuation region and the second optical attenuation region and configured to change a phase of the illumination radiation by altering an optical property of the substrate, wherein the phase adjustment region projects outwardly from a second side of the substrate opposing a first side of the substrate that includes the first optical attenuating region and the second optical attenuating region.