20090323039 | Correction Method for Non-Uniform Reticle Heating in a Lithographic Apparatus - A method that includes conditioning a radiation beam, imparting the radiation beam with a pattern to form a patterned radiation beam by a reticle having a pattern image area and a reticle mark, and projecting the patterned radiation beam onto a target portion of a substrate by a projection system. The method further includes illuminating the reticle mark by the radiation beam for generating an aerial image of the reticle, projecting the aerial image on an image sensor, collecting image data from the image sensor, obtaining from the image data positional parameters of the aerial image, and correcting any deviation of the positional parameters from a required position of the aerial image by compensating an illumination induced thermal expansion of the reticle by an estimated correction of magnification settings of the projection system, the estimated correction being calculated from a prediction of the temporal thermal expansion of the reticle. | 12-31-2009 |