Patent ID: 8638370

Claim:
An apparatus for processing a substrate, including a mark to be detected for positioning the substrate, the apparatus comprising: an illuminator configured to illuminate the mark, the illuminator including a shutter, which opens and closes an optical path thereof, and determine an illumination period during which the mark is to be illuminated; an image pickup device configured to pick up an image of the mark illuminated by the illuminator; and a storage device configured to store correction data for correcting, regarding an illuminance unevenness of the illuminator that depends on the illumination period, an output of the image pickup device with respect to each of a plurality of illumination periods, wherein the apparatus is configured to obtain the correction data from the storage device in accordance with the illumination period, and to correct the output of the image pickup device using the obtained correction data, and wherein the storage device is configured to store, as the correction data for each pixel of the image pickup device, a coefficient of a first-order term and a coefficient of a zeroth-order term of a linear function of the output with respect to each of the plurality of illumination periods.