A multilayer mirror for reflecting Extreme Ultraviolet (EUV) radiation and a method for producing the same are disclosed. In an embodiment a multilayer mirror includes a layer sequence having a plurality of alternating first layers and second layers, the first layers including lanthanum or a lanthanum compound and the second layers including boron, wherein the second layers are doped with carbon, and wherein a molar fraction of carbon in the second layers is 10% or less.

A reflective film coated substrate includes a substrate having two main surfaces opposite to each other and end faces connected to outer edges of the two main surfaces; and a reflective film formed on one of the main surfaces and extending onto at least part of the end faces. The reflective film on the main surface has a multilayer structure including low refractive index layers and high refractive index layers alternately formed. The reflective film which extends onto the end faces has a single-layer structure containing a first element higher in content than any other element in the low refractive index layers and a second element higher in content than any other element in the high refractive index layers.

A radiation source apparatus includes a vessel, a laser source, a collector, and a reflective mirror. The vessel has an exit aperture. The laser source is at one end of the vessel and configured to excite a target material to form a plasma. The collector is disposed in the vessel and configured to collect a radiation emitted by the plasma and to direct the collected radiation to the exit aperture of the vessel. The reflective mirror is in the vessel and configured to reflect the laser beam toward an edge of the vessel.

Collection reflectors with multiple reflector elements defined on a curved surface are used to collect EUV optical radiation from an EUV emitting area. Each of the reflector elements can image the emitting area at or near a corresponding reflective element of a second multi-element reflector that overlaps radiation from each of the multiple reflector element of the collection reflector to illuminate a grating reticle. Systems with such a collection reflector can use fewer optical elements. In addition, grating reticles are defined on a curve substrate an include a plurality of grating phase steps so that the grating reticle provides phase curvature along two axes but with physical curvature along a single axis. Methods of producing varying duty cycle 1D patterns are also disclosed.

An imaging device of an embodiment comprises an aperture that transmits imaging light applied to a sample, a detector including a linear sensor comprising a linear light receiving surface extending in a first direction, a first image forming element that collects components of the imaging light in the first direction and forms an image on the light receiving surface with a first wave front aberration amount, and a second image forming element that collects components of the imaging light in a second direction orthogonal to the first direction and forms an image on the light receiving surface with a second wave front aberration amount smaller than the first wave front aberration amount.

An assembly, for example in a microlithographic projection exposure apparatus, comprises an optical element and a joint arrangement for mechanically bearing the optical element. The joint arrangement comprises at least one connecting element secured on the optical element. The mass of the connecting element is distributed over its length so that the moment of inertia of the connecting element is increased in comparison with a connecting element of identical mass and length in which the mass is distributed uniformly over the length.

A mirror for extreme ultraviolet light includes: a substrate (41); a multilayer film (42) provided on the substrate and configured to reflect extreme ultraviolet light; and a capping layer (53) provided on the multilayer film, and the capping layer includes a first layer (61) containing an oxide of a metal, and a second layer (62) arranged between the first layer and the multilayer film and containing at least one of a boride of the metal and a nitride of the metal.

A pulse width expansion apparatus according to an aspect of the present disclosure includes a polarization beam splitter and a transfer optical system. The transfer optical system includes ¼-wavelength and reflection mirror pairs. The ¼-wavelength mirror pair include first and second ¼-wavelength mirrors. The first ¼-wavelength mirror provides ¼-wavelength phase shift and reflects a pulse laser beam. The second ¼-wavelength mirror provides ¼-wavelength phase shift and reflects the pulse laser beam reflected by the first ¼-wavelength mirror. The reflection mirror pair are disposed on an optical path before and after or between the ¼-wavelength mirror pair. The transfer optical system transfers an image of an input pulse laser beam on the polarization beam splitter to the optical path between the ¼-wavelength mirror pair at one-to-one magnification as a first transfer image and transfers the first transfer image to the polarization beam splitter at one-to-one magnification as a second transfer image.

An exposure tool is configured to remove contaminants and/or prevent contamination of mirrors and/or other optical components included in the exposure tool. In some implementations, the exposure tool is configured to flush and/or otherwise remove contaminants from an illuminator, a projection optics box, and/or one or more other subsystems of the exposure tool using a heated gas such as ozone (O.sub.3) or extra clean dry air (XCDA), among other examples. In some implementations, the exposure tool is configured to provide a gas curtain (or gas wall) that includes hydrogen (H.sub.2) or another type of gas to reduce the likelihood of contaminants reaching the mirrors included in the exposure tool. In this way, the mirrors and one or more other components of the exposure tool are cleaned and maintained in a clean environment in which radiation absorbing contaminants are controlled to increase the performance of the exposure tool.

An illumination optical unit for EUV projection lithography includes a field facet mirror with a plurality of field facets for guiding illumination light into an object field where a lithography mask is arrangeable. At least one spectral output coupling mirror section is arranged on the field facet mirror. The mirror section serves to output couple the spectral analysis partial beam from a beam path of the illumination light. A detector serves for the spectral analysis of the spectral analysis partial beam. This can yield an illumination optical unit in which process monitoring during the projection exposure is improved.