An apparatus for generating extreme ultraviolet (EUV) light includes a raw material supply unit supplying a plasma source for generating EUV light. An EUV light source unit uses a laser to generate plasma from the plasma source. A filter is configured to extract EUV light from the light. A first protective layer is disposed on a front surface of the filter. A frame having a first region exposing at least a portion of the filter or the first protective layer is disposed on the first protective layer. A width of the first region is smaller than a width of the first protective layer and smaller than or equal to a width of the filter.

A reflective optical element (17), in particular for reflecting EUV radiation (16), includes: a substrate (25), and a reflective coating (26) applied to the substrate (25). In one disclosed aspect, the substrate (25) is doped within its volume (V) with at least one precious metal (27). In a further disclosed aspect, the reflective coating (26) and/or a structured layer (28) that is formed between the substrate (25) and the reflective coating (26) is doped with at least one precious metal (27). Also disclosed are an optical arrangement, preferably a projection exposure apparatus for microlithography, in particular for EUV lithography, which includes at least one such reflective optical element (17), and a method of producing such a reflective optical element (17).

Nanostructured photonic materials and associated components for use in devices and systems operating at ultraviolet (UV), extreme ultraviolet (EUV), and/or soft Xray wavelengths are described. Such a material may be fabricated with nanoscale features tailored for a selected wavelength range, such as at particular UV, EUV, or soft Xray wavelengths or wavelength ranges. Such a material may be used to make components such as mirrors, lenses or other optics, panels, lightsources, masks, photoresists, or other components for use in applications such as lithography, wafer patterning, biomedical applications, or other applications.

Nanostructured photonic materials, and associated components for use in devices and systems operating at ultraviolet (UV), extreme ultraviolet (EUV), and/or soft Xray wavelengths are described. Such a material may be fabricated with nanoscale features tailored for a selected wavelength range, such as at particular UV, EUV, or soft Xray wavelengths or wavelength ranges. Such a material may be used to make components such as mirrors, lenses or other optics, panels, lightsources, masks, photoresists, or other components for use in applications such as lithography, wafer patterning, astronomical and space applications, biomedical applications, biotech or other applications.

A method for producing an optical element (2), in particular for a projection exposure system (400), according to which a protective layer (11) consisting of a protective material is applied to a surface of a main body (7) until a protective layer thickness is obtained. The main body (7) has a substrate (17) and a reflective layer (18) applied to the substrate (17). The protective layer (11) is at least substantially defect-free.

Treating a reflective optical element (104) for the EUV wavelength range that has a reflective coating on a substrate. The reflective optical element in a holder (106) is irradiated with at least one radiation pulse of a radiation source (102) having a duration of between 1 μs and 1 s. At least one radiation source (102) and the reflective optical element move relative to one another. Preferably, this is carried out directly after applying the reflective coating in a coating chamber (100). Reflective optical elements of this type are suitable in particular for use in EUV lithography or in EUV inspection of masks or wafers, for example.

An illumination optical system for projection lithography includes a pupil facet mirror having pupil facets. For at least some of the pupil facets which are designed as selectively reflecting pupil facets, the selectively reflecting pupil facet has a reflective coating for the illumination light, wherein a first coating area on a first part of the selectively reflecting pupil facet has a first reflectivity, a second coating area on a second part of the selectively reflecting pupil facet has a second reflectivity, the first coating area is different from the second coating area, and the first reflectivity is different from the second reflectivity. In combination or as an alternative, for at least some of the pupil facets which are designed as broadbands reflecting pupil facets, the broadband reflecting facets have a broadband reflective coating for the illumination light.

A multilayer stack in the form of a Bragg reflector comprising a graded interfacial layer and a method of manufacturing are disclosed. The graded interfacial layer eliminates the formation of low-reflectivity interfaces in a multilayer stack and reduces roughness of interfaces in a multilayer stack.

Strontium tetraborate can be used as an optical material. Strontium tetraborate exhibits high refractive indices, high optical damage threshold, and high microhardness. The transmission window of strontium tetraborate covers a very broad range of wavelengths, from 130 nm to 3200 nm, making the material particularly useful at VUV wavelengths. An optical component made of strontium tetraborate can be incorporated in an optical system, such as a semiconductor inspection system, a metrology system, or a lithography system. These optical components may include mirrors, lenses, lens arrays, prisms, beam splitters, windows, lamp cells or Brewster-angle optics.

An apparatus for generating extreme ultraviolet (EUV) light includes a raw material supply unit supplying a plasma source for generating EUV light. An EUV light source unit uses a laser to generate plasma from the plasma source. A filter is configured to extract EUV light from the light. A first protective layer is disposed on a front surface of the filter. A frame having a first region exposing at least a portion of the filter or the first protective layer is disposed on the first protective layer. A width of the first region is smaller than a width of the first protective layer and smaller than or equal to a width of the filter.