Patent ID: 7787177

Claim:
A projection objective configured to image a pattern provided in an object surface of the projection objective onto an image surface of the projection objective, the projection objective comprising: an object-side imaging subsystem configured to create an intermediate image closest to the image surface from radiation coming from the object surface; and an image-side imaging subsystem configured to directly image the intermediate image onto the image surface, the image-side imaging subsystem comprising: a diverting lens group configured to create a divergent beam from radiation coming from the intermediate image; a converging lens group including an optical element closest to the image surface configured to convert the divergent beam into a convergent beam having an aperture sin α≧0.8 in the optical element to provide an image-side numerical aperture NA; a primary correcting group including a primary correcting lens having an aspheric primary correcting surface formed by an image-side concave surface, the primary correcting group being in a region of the divergent beam such that a primary angular load defined by a primary local maximum SINIMAX 1 for the sine of the angle of incidence of radiation on the aspheric primary correcting surface of the correcting lens is obtained and such that a primary subaperture offset SO 1 is given on the primary correcting surface; and a secondary correcting group including at least one secondary correcting lens having an aspheric secondary correcting surface, wherein the secondary correcting surface is shaped and arranged such that a secondary local maximum SINIMAX 2 for the sine of the angle of incidence similar to the primary local maximum SINIMAX 1 is obtained on the secondary correcting surface and arranged at a position where an absolute value of a secondary subaperture offset SO 2 is similar to, but different from, the absolute value of the first subaperture offset S 01 , where a subaperture offset SO between a first subaperture SA 1 corresponding to a first object point of minimum height and a second subaperture SO 2 corresponding to a second object point with maximum height is defined as: SO=D SA /DIA SA , where D SA is a distance between the centers of the first and the second subaperture in an offset direction and DIA SA is the mean value of the diameters of the first and second subaperture in the offset direction.