Patent ID: 6969864

Claim:
A photomask inspection system to detect defects in a photomask, wherein an image of the photomask is produced on a wafer plane by an optical system having a platform, the system comprising: an image sensor unit capable of being disposed on or the platform, the image sensor unit includes: a sensor array, capable of being located in the wafer plane, including a plurality of sensor cells wherein each sensor cell includes an active area to sample the intensity of light of a predetermined wavelength that is incident thereon and wherein, at discrete locations relative to the image of the photomask produced on the wafer plane, the sensor cells sample the intensity of light; and a film, disposed over selected portions of the active areas of the plurality of sensor cells, to increase the spatial resolution of each sensor cell wherein the film is comprised of a material that impedes passage of light of the predetermined wavelength; and a first processing unit, coupled to the image sensor unit, to compare data which is representative of the intensity of light sampled by a plurality of sensor cells at the discrete locations to associated data of a mask pattern design database, wherein the mask pattern design database includes data which is representative of the features on the photomask.