A catoptric system for EUV lithography includes six freeform reflective surfaces that are specified based on fringe Zernike polynomials. Each of the surfaces is tilted and/or decentered in a meridian plane and with respect to a common axis so that image and object planes are parallel. Rectangular fields can be imaged with image space numerical aperture of at least 0.5.

An imaging optical unit for projection lithography has a plurality of mirrors for guiding imaging light from an object field in an object plane into an image field in an image plane along an imaging light beam path. At least two of the mirrors are embodied as GI mirrors. Exactly one stop serves to predefine at least one section of an outer marginal contour of a pupil of the imaging optical unit. The stop is arranged spatially in front of a penultimate mirror in the imaging light beam path. This results in an imaging optical unit that is well defined with regard to its pupil and is optimized for projection lithography.

A lithographic apparatus includes a projection system which includes a plurality of optical elements configured to project a beam of radiation onto a radiation sensitive substrate. The lithographic apparatus also includes a metrology frame structure which includes a part of one or more optical element measurement systems to measure the position and/or orientation of at least one of the optical elements. The plurality of optical elements, a patterning device stage, and a substrate stage are arranged such that, in a two dimensional view on the projection system, a rectangle is defined such that it envelops the plurality of optical elements, the patterning device stage, and the substrate stage. The rectangle is as small as possible. The metrology frame structure is positioned within the rectangle.

An EUV illumination device and related method for operating a microlithographic projection exposure apparatus designed for operation in the EUV. An EUV illumination device comprises a first reflective component, a second reflective component and an exchange apparatus by which the first reflective component and the second reflective component in the optical beam path are exchangeable for one another. A polarization degree, defined as a ratio between the reflectivities for s-polarized and p-polarized radiation, for the first reflective component is at least 1.5 times greater than for the second reflective component.

A method for determining a position of a mirror of an optical system comprises: a) providing at least one parameter from a mechanical model of the mirror, b) interferometrically detecting a temporal change in a distance of a point of a curved mirror effective surface; and c) ascertaining an amplitude and a phase of N eigenmodes from the temporal change in the distance and the at least one parameter to determine the position of the mirror.

There is provided a reflective image-forming optical system which is applicable to an exposure apparatus using, for example, EUV light and which is capable of increasing numerical aperture while enabling optical path separation of light fluxes. In a reflective imaging optical system (6) forming an image of a first plane (4) onto a second plane (7), the numerical aperture on a side of the second plane with respect to a first direction (X direction) on the second plane is greater than 1.1 times a numerical aperture on the side of the second plane with respect to a second direction (Y direction) crossing the first direction on the second plane. The reflecting imaging optical system has an aperture stop (AS) defining the numerical aperture on the side of the second plane, and the aperture stop has an elliptic-shaped opening of which size in a major axis direction (X direction) is greater than 1.1 times that in a minor axis direction (Y direction).

A reflective exposure apparatus includes a platform, an illuminating system, a photomask, a chip, and a reflecting convex mirror. The photomask is formed on the platform and faces the illuminating system. The chip is formed on the platform. The illuminating system and the reflecting curved mirror are formed on opposite sides of the platform. The platform can be moved relative to the illuminating system and the reflecting curved mirror.

A method for aligning a mirror of a microlithographic projection exposure apparatus, according to one formulation, involves: recording a first partial interferogram between a wave reflected at a first mirror segment (101) and a reference wave reflected at a reference surface (110, 310, 510), recording a second partial interferogram between a wave reflected at a second mirror segment (102) and a reference wave reflected at the reference surface, determining a phase offset between the first partial interferogram and the second partial interferogram, and aligning the first mirror segment and the second mirror segment in relation to one another in accordance with the determined phase offset, so that the distance of the relevant mirror segments (101, 102) from a respective predetermined, hypothetical surface in the direction of the respective surface normal is less than /10 at each point on the mirror segments, where denotes the operating wavelength of the mirror.

A projection optical unit images an object field in an image field. The projection optical unit includes a plurality of mirrors guides imaging light from the object field to the image field. At least two of the mirrors are arranged directly behind one another in the beam path of the imaging light for grazing incidence with an angle of incidence of the imaging light which is greater than 60?. This results in an imaging optical unit that can exhibit a well-corrected imageable field with, at the same time, a high imaging light throughput.

An imaging optical system for a projection exposure system has at least one anamorphically imaging optical element. This allows a complete illumination of an image field in a first direction with a large object-side numerical aperture in this direction, without the extent of the reticle to be imaged having to be enlarged and without a reduction in the throughput of the projection exposure system occurring.