Patent ID: 6977714

Claim:
A lithographic apparatus comprising: a radiation system configured to provide a projection beam of radiation, said radiation system having an exposure energy setting and an illumination setting; a support structure configured to support patterning structure, the patterning structure serves 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 and information on spatial-frequency dependence of the reference lithographic transfer function, and (B) a change of at least one of said exposure energy setting and said illumination setting to reduce said difference.