A collector mirror for an EUV microlithography system. The collector mirror includes an optical grating having an optically effective mirror surface, which reflects electromagnetic used rays in an EUV spectral range emanating from a first focal point and focuses them onto a second focal point. The first and second focal points lie on a side of the optical grating facing the mirror surface and define an optical axis. The optical grating is configured, in interaction with a stop arranged at the second focal point, to allow the used rays to pass through the stop and to block electromagnetic remaining rays in a remaining spectral range different than the EUV spectral range. The optical grating includes a blazed grating composed of a plurality of mirror facets, each having a facet surface. The facet surfaces form the mirror surface of the blazed grating.

Disclosed is an illumination system for a metrology apparatus and a metrology apparatus comprising such an illumination system. The illumination system comprises an illumination source; and a linear variable filter arrangement configured to filter a radiation beam from said illumination source and comprising one or more linear variable filters. The illumination system is operable to enable selective control of a wavelength characteristic of the radiation beam subsequent to it being filtered by the linear variable filter arrangement.

An EUV collector mirror has a reflection surface (16) to reflect usable EUV light which impinges on the reflection surface (16) from a source region (17) to a subsequent EUV optics. The reflection surface (16) carries a pump light grating structure (19) configured to retroreflect pump light (22) which impinges upon the pump light grating structure (19) from the source region (17) back to the source region (17). The pump light (22) has a wavelength deviating from the wavelength of the usable EUV light. Such EUV collector mirror enables a high conversion efficiency between the energy of pump light of a laser discharged produced plasma (LDPP) EUV light source on the one hand and the resulting usable EUV energy on the other.

Apparatus for and method of controlling a laser system capable of generating bursts of pulses of laser radiation having multiple alternate wavelengths in which an element controlling the wavelength is pre-positioned between bursts to be between its position for generating one wavelength and its position for generating another wavelength. Also disclosed is a system that determines an optimal control waveform for the element to move between positions using quadratic programming, dynamic programing, inversion feed forward control, or iterative learning control. A data storage device such as a pre-populated lookup table or a field programmable gate array may be used to store at least one optimal control parameter for each of a plurality of repetition rates.

An optical fiber, manufacturing intermediate for forming an optical fiber and a method for forming an optical fiber. The method includes providing a manufacturing intermediate having an elongate body and having an aperture extending through the elongate body along an axial dimension of the elongate body, a boundary of the aperture defining an internal surface of the manufacturing intermediate. The method further includes etching the internal surface of the manufacturing intermediate using an etching substance, and drawing the manufacturing intermediate along the axial dimension so as to form the optical fiber.

An exposure apparatus configured to expose a substrate to light from a solid-state light emitting element, includes an illumination optical system configured to illuminate a mask with the light, and a projection optical system configured to project an image of a pattern of the mask onto the substrate, wherein a pupil plane intensity distribution, which is a light intensity distribution on a pupil plane included in the illumination optical system and optically conjugated with a light emission plane of the solid-state light emitting element, is a light intensity distribution in which a maximum intensity is achieved outside an optical axis of the illumination optical system, and wherein the pupil plane intensity distribution is a light intensity distribution on the pupil plane onto which a light emission distribution of the light emission plane is projected with a predetermined magnification.

An optical diffraction component is configured to suppress at least one target wavelength by destructive interference. The optical diffraction component includes at least three diffraction structure levels that are assignable to at least two diffraction structure groups. A first of the diffraction structure groups is configured to suppress a first target wavelength λ.sub.1. A second of the diffraction structure groups is configured to suppress a second target wavelength λ.sub.2, where (λ.sub.1−λ.sub.2).sup.2/(λ.sub.1+λ.sub.2).sup.2<20%. A topography of the diffraction structure levels can be described as a superimposition of two binary diffraction structure groups. Boundary regions between adjacent surface sections of each of the binary diffraction structure groups have a linear course and are superimposed on one another at most along sections of the linear course.

The present disclosure provides an interference filter, a lithography system incorporating an interference filter, and a method of fabricating an interference filter. The interference filter includes a transparent substrate having a front surface and a back surface, a plurality of alternating material layers formed over the front surface of the transparent substrate that form a bandpass filter, and an anti-reflective structure formed over the back surface of the transparent substrate. The alternating material layers alternate between a relatively high refractive index material and a relatively low refractive index material.

An optical diffraction component has a periodic grating structure profile. The diffraction structure levels are arranged so that a wavelength range around two different target wavelengths diffracted by the grating structure profile has radiation components with three different phases that interfere destructively with one another. Diffraction structure levels predefine a topography of a grating period of the grating structure profile that is repeated regularly along a period running direction. These include a neutral diffraction structure level, a positive diffraction structure level raised relative thereto, and a negative diffraction structure level lowered relative thereto. The neutral diffraction structure level has an extent along the period running direction which is less than 50% of the extent of the grating period. A difference between the two target wavelengths is less than 50%. The result is an optical diffraction component whose possibilities for use can be extended, for example, to stray light suppression.

Systems, methods, and computer programs for increasing a contrast for a lithography system are disclosed. In one aspect, a method of optimizing a process for imaging a feature on a substrate using a photolithography system is disclosed, the method including obtaining an optical spectrum of a light beam for the imaging, wherein the light beam includes pulses having a plurality of different wavelengths, and narrowing the optical spectrum of the pulses of the light beam for the imaging to improve a quality metric of the imaging.