A beam-splitting apparatus arranged to receive an input radiation beam and split the input radiation beam into a plurality of output radiation beams. The beam-splitting apparatus comprising a plurality of reflective diffraction gratings arranged to receive a radiation beam and configured to form a diffraction pattern comprising a plurality of diffraction orders, at least some of the reflective diffraction gratings being arranged to receive a 0.sup.th diffraction order formed at another of the reflective diffraction gratings. The reflective diffraction gratings are arranged such that the optical path of each output radiation beam includes no more than one instance of a diffraction order which is not a 0.sup.th diffraction order.

A system includes a plate configured for mounting of a reflective extreme ultra-violet (EUV) mask thereon and a zone plate configured to divide EUV light into zero-order light and first-order light and to pass the zero-order light and the first-order light to the reflective EUV mask. The system further includes a detector configured to receive EUV light reflected by the EUV mask and including a zero-order light detection region configured to generate a first image signal and a first-order light detection region configured to generate a second image signal, and a calculator configured to generate a compensated third image signal from the first image signal and the second image signal. The third image signal may be used to determine a distance between mask patterns of the EUV mask.

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.

According to one embodiment, a prism system is provided. The prism system includes a polarizing beam splitter (PBS) surface. The PBS surface is configured to generate first and second sub-beams having corresponding first and second polarization information from a received beam, the second polarization information being different than the first polarization information. A first optical path of the first sub-beam within the prism system has substantially same length as a second optical path of the second sub-beam within the prism system. Additionally or alternatively, the first sub-beam achieves a predetermined polarization extinction ratio.

A reflective optical element for the extreme ultraviolet (EUV) wavelength range having a multi-layer system extending over an area on a substrate. The system includes layers (54, 55′) made of at least two different materials with different real parts of the refractive index in the EUV arranged alternately. A layer of one of the two materials forms a stack with the layer or layers arranged between this layer and the nearest layer of the same material with increasing distance from the substrate. In at least one stack (53′), the material of the layer (55′) with the lower real part of the refractive index and/or the material of the layer (54) with the larger real part of the refractive index is a combination (551, 552) made of at least two substances.

A cost-effective method for repairing reflective optical elements for EUV lithography. These optical elements (60) have a substrate (61) and a coating (62) that reflects at a working wavelength in the range between 5 nm and 20 nm and is damaged as a result of formation of hydrogen bubbles. The method includes: localizing a damaged area (63, 64, 65, 66) in the coating (62) and covering the damaged area (63, 64, 65, 66) with one or more materials having low hydrogen permeability by applying a cover element to the damaged area. The cover element is formed of a surface structure, a convex or concave surface, or a coating corresponding to the coating of the reflective optical element, or a combination thereof. The method is particularly suitable for collector mirrors (70) for EUV lithography. After the repair, the optical elements have cover elements (71, 72, 73).

The invention relates to a device for determining the exposure energy during the exposure of an element in an optical system, in particular for microlithography, comprising an optical element, a diffractive structure which has a locally varying grating period, and an intensity sensor arrangement, wherein electromagnetic radiation diffracted at the diffractive structure during operation of the optical system, in at least one order of diffraction, is directed to the intensity sensor arrangement by way of total internal reflection effected in the optical element.

Disclosed are systems and methods for achieving sub-diffraction limit resolutions for fabrication of integrated circuits. In one embodiment, a photolithography system is disclosed. The system includes a light source, configured to emit laser beams; a reflector configured to receive the laser beams and focus the laser beams on a condensing lens; a scattering medium, configured to receive the laser beams and generate scattered laser beams; and a wave-front shaping module, configured to receive the scattered laser beams and generate a focused laser beam on a silicon wafer.

One of gamma ray lithography systems includes a gamma ray generator and a wafer stage. The gamma ray generator is configured to generate a substantially uniform gamma ray. The gamma ray generator includes a plurality of gamma ray sources and a rotational carrier. The rotational carrier is configured to hold the gamma ray sources and rotate along a rotational axis. The wafer stage is disposed below the gamma ray generator and configured to secure a wafer.

Disclosed are systems and methods for achieving sub-diffraction limit resolutions for fabrication of integrated circuits. In one embodiment, a photolithography system is disclosed. The system includes a light source, configured to emit laser beams; a reflector configured to receive the laser beams and focus the laser beams on a condensing lens; a scattering medium, configured to receive the laser beams and generate scattered laser beams; and a wave-front shaping module, configured to receive the scattered laser beams and generate a focused laser beam on a silicon wafer.