Patent ID: RE43643

Claim:
A lithographic apparatus comprising: a radiation system an illuminator configured to provide manipulate a projection beam of radiation, said radiation system illuminator having an exposure energy setting and an illumination setting; a support structure configured to support hold a patterning structure, the patterning structure serves configured to pattern the projection beam according to a desired pattern; a substrate table configured to hold a substrate; a projection system configured to project the patterned beam onto a target portion of the substrate; a memory device that provides information on spatial-frequency dependence of a lithographic transfer function of the lithographic apparatus and information on spatial-frequency dependence of a reference lithographic transfer function ; and a processor configured to calculate (A) a difference between the information on spatial-frequency dependence of the lithographic transfer function of the lithographic apparatus spatial-frequency dependence on pitch of a feature error of a projected image by the lithographic apparatus at three or more pitches and reference information on spatial-frequency dependence of the reference lithographic transfer function at said three or more pitches on said spatial-frequency dependence on pitch , and (B) a change of at least one of said exposure energy setting and , or said illumination setting , or both said exposure energy setting and said illumination setting, to reduce said difference.