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).

An imaging optical unit for EUV microlithography is configured so that, when used in an optical system for EUV microlithography, relatively high EUV throughput and high imaging quality can achieved.

An illumination optical unit for projection lithography illuminates an object field with illumination light along an illumination beam path. The arrangement of field facets of a field facet mirror and also of pupil facets of a pupil facet mirror is such that an illumination channel is guided over each of them. The field facet mirror images a light source image along in each case one illumination channel onto one of the pupil facets. The pupil facet mirror superimposedly images of the field facets into the object field. The illumination optical unit is designed for the settable specification of a spatial resolution of an illumination light illumination of an entrance pupil of a projection optical unit arranged downstream of the object field in the illumination light beam path. The result of this is an illumination optical unit with which illumination light can be used efficiently for high-contrast imaging of the structures to be projected.

An imaging optical unit includes a plurality of mirrors to guide imaging light along an imaging beam path. The plurality of mirrors includes a number of mirrors for grazing incidence (GI mirrors), which deflect a chief ray of a central object field point with an angle of incidence of more than 45. At least two of the GI mirrors are in the imaging beam path as basic GI mirrors so that the deflection effect thereof adds up for the chief ray. At least one further GI mirror is arranged in the imaging beam path as a counter GI mirror so that the deflection effect thereof acts in subtractive fashion for the chief ray in relation to the deflection effect of the basic GI mirrors. This can yield an imaging optical unit having enhanced flexibility in relation to an installation space used for mirror bodies of the mirrors of the imaging optical unit.

The present disclosure relates to a lithography scanner including: a light source configured to emit extreme ultra-violet (EUV) light; a pellicle including an EUV transmissive membrane that is configured to scatter the EUV light into an elliptical scattering pattern having a first major axis; a reticle configured to reflect the scattered EUV light through the pellicle; and an imaging system configured to project a portion of the reflected light that enters an acceptance cone of the imaging system onto a target wafer, wherein a cross section of the acceptance cone has a second major axis, and wherein the pellicle is arranged such that the first major axis is oriented at an angle relative to the second major axis.

The present invention relates to a lithographic apparatus, comprising: a base frame (10), adapted for mounting the lithographic apparatus (1) on a support surface (9), a projection system (20) comprising: a force frame (30), an optical element (21) which is moveable relative to the force frame, a sensor frame (40), which is separate from the force frame, at least one sensor which is adapted to monitor the optical element, comprising at least one sensor (25) element which is mounted to the sensor frame, a force frame support (31), which is adapted to support the force frame on the base frame, an intermediate frame (45), which is separate from the force frame, a sensor frame coupler (41), which is adapted to couple the sensor frame to the intermediate frame, an intermediate frame support (46), which is separate from the force fame support and adapted to support the intermediate frame on the base frame.

When producing a mirror as an optical component for an optical system of a projection exposure apparatus for projection lithography, first, an average value of a global gravitational acceleration is determined. Next, a gravitational acceleration difference between the gravitational acceleration at the production location and the gravitational acceleration average value is determined. After a determination of a target surface shape of a reflection surface of the mirror, a mirror substrate is machined at the production location taking into consideration the gravitational acceleration difference in a manner such that, under the influence of the gravitational acceleration average value, a current surface shape of the reflection surface of the mirror substrate does not deviate from the target surface shape by more than a prescribed figure tolerance value (P.sub.max). The result is an optical element with a relatively small figure at a use location of the mirror.

A projection lens of an EUV-lithographic projection exposure system with at least two reflective optical elements each comprising a body and a reflective surface for projecting an object field on a reticle onto an image field on a substrate if the projection lens is exposed with an exposure power of EUV light, wherein the bodies of at least two reflective optical elements comprise a material with a temperature dependent coefficient of thermal expansion which is zero at respective zero cross temperatures, and wherein the absolute value of the difference between the zero cross temperatures is more than 6K.

An illumination optical system is used with a reflective imaging optical system configured to form an image of a pattern arranged on a first plane onto a second plane, and is configured to illuminate an illumination area on the first plane with a light from a light source. The illumination optical system includes one or more reflecting mirrors configured to reflect the light from the light source to the first plane such that the reflected light reaches the first plane after crossing an optical path of a light which travels in the reflective imaging optical system.

An imaging optical unit for projection lithography has a plurality of mirrors for guiding imaging light from an object field into an image field. The object field is spanned by two object field coordinates, with a normal coordinate being perpendicular thereto. Imaging light propagates in a first imaging light plane through at least one first plane intermediate image of the imaging optical unit. In a second imaging light plane, the imaging light propagates through at least one second plane intermediate image of the imaging optical unit. The number of first plane intermediate images and the number of second plane intermediate images differ from one another. An imaging optical unit with reduced production costs emerges.