A lamp having a fin provided in a periphery of a metal base. The fin includes a first surface close to a bright spot of a light-emitting tube and a second surface far from the bright spot on an opposite side of the first surface. A distance between a first inner edge of the first surface and a bright spot plane as a plane orthogonal to a center axis of the metal base including the bright spot is shorter than a distance between the bright spot plane and a first outer edge of the first surface. A distance between the first inner edge and the first outer edge of the first surface is not shorter than a distance between a second inner edge and a second outer edge of the second surface.

A method includes: depositing a mask layer over a substrate; directing first radiation reflected from a central collector section of a sectional collector of a lithography system toward the mask layer according to a pattern; directing second radiation reflected from a peripheral collector section of the sectional collector toward the mask layer according to the pattern, wherein the peripheral collector section is vertically separated from the central collector section by a gap; forming openings in the mask layer by removing first regions of the mask layer exposed to the first radiation and second regions of the mask layer exposed to the second radiation; and removing material of a layer underlying the mask layer exposed by the openings.

An optical element (1)includes: a substrate (2), applied to the substrate (2), a multilayer system (3) which reflects EUV radiation (4), and applied to the multilayer system (3), a protective layer system (5) having an uppermost layer (5a). Nanoparticles (7) are embedded into the material of the uppermost layer (5a) of the protective layer system (5) which nanoparticles contain at least one metallic material. An EUV lithography system which includes at least one such optical element (1) designed as indicated above, and a method of forming nanoparticles (7) in the uppermost layer (5a) of the protective layer system (5) are also disclosed.

An optical element (11) has an optical surface (20) with a diffraction structure (21). The optical surface (20) is curved such that a distance-to-diameter ratio between a distance A between a deepest point (T) and a highest point (H) and a largest diameter D is greater than 1/10. When producing the optical element (11), firstly a raw optical element having a raw optical surface to be provided with the diffraction structure (21) is provided. The raw optical surface is then coated with a photoresist with the aid of an isotropic deposition method and the photoresist is exposed and then developed. This results in a production method for an optical element with an optical surface having a diffraction structure, which method satisfies stringent requirements made of a structure accuracy when producing the diffraction structure.

An EUV collector has a reflection surface with a basic mirror shape of a spherical section. A diffraction grating for EUV used light is applied to the reflection surface. The diffraction grating is designed so that the EUV used light, which emanates from a sphere center of the spherical section, is diffracted by the diffraction grating toward a collection region. The collection region is spatially spaced apart from the sphere center. This creates an EUV collector in which an effective separation between EUV used light, which is to be collected with the aid of the collector, and extraneous light having a wavelength that differs from a used light wavelength is made possible.

A light source is provided capable of maintaining the temperature of a collector surface at or below a predetermined temperature. The light source in accordance with various embodiments of the present disclosure includes a processor, a droplet generator for generating a droplet to create extreme ultraviolet light, a collector for reflecting the extreme ultraviolet light into an intermediate focus point, a light generator for generating pre-pulse light and main pulse light, and a thermal image capture device for capturing a thermal image from a reflective surface of the collector.

A faceted reflector (32, 32″) for receiving an incident radiation beam (2) and directing a reflected radiation beam at a target. The faceted reflector comprises a plurality of facets, each of the plurality of facets comprising a reflective surface. The reflective surfaces of each of a first subset of the plurality of facets define respective parts of a first continuous surface and are arranged to reflect respective first portions of the incident radiation beam in a first direction to provide a first portion of the reflected radiation beam. The reflective surfaces of each of a second subset of the plurality of facets define respective parts of a second continuous surface and are arranged to reflect respective second portions of the incident radiation beam in a second direction to provide a second portion of the reflected radiation beam.

An extreme ultraviolet (EUV) collector inspection apparatus and method capable of precisely inspecting a contamination state of an EUV collector and EUV reflectance in accordance with the contamination state are provided. The EUV collector inspection apparatus includes a light source arranged in front of an EUV collector to be inspected and configured to output light in a visible light (VIS) band from UV rays, an optical device configured to output narrowband light from the light, and a camera configured to perform imaging from an UV band to a VIS band. An image by wavelength of the EUV collector is obtained by using the optical device and the camera and a contamination state of the EUV collector is inspected.

A spheroidal mirror reflectivity measuring apparatus for extreme ultraviolet light may include an extreme ultraviolet light source, an optical system, and a first photosensor. The extreme ultraviolet light source may be configured to output extreme ultraviolet light to a spheroidal mirror that includes a spheroidal reflection surface. The optical system may be configured to allow the extreme ultraviolet light to travel to the spheroidal reflection surface via a first focal position of the spheroidal mirror. The first photosensor may be provided at a second focal position of the spheroidal mirror, and may be configured to detect the extreme ultraviolet light that has passed through the first focal position and then has been reflected by the spheroidal reflection surface.

A light source apparatus configured to emit light includes a condenser unit configured to reflect light from a light source and to condense the light on a condensing point, a light shielding unit disposed on an optical path of the light from the condenser unit, and a reflector unit disposed between the condenser unit and the light shielding unit and configured to reflect the light from the condenser unit. The reflector unit is disposed so that reflected light is condensed by the condenser unit toward the condensing point.