An optical assembly includes a bulb and a lens for a laser-operated light source. The bulb has a chamber for accommodating an ionizable gas and a plasma formed by energizing the ionizable gas and has a longitudinal axis and a transverse axis perpendicular to the longitudinal axis. In use, the lens is arranged to focus a wavefront of radiation from a laser to a virtual object point located inside the chamber. In use, the bulb is arranged to transmit and refract the wavefront of the radiation to a first real image point in a first cross-section of the longitudinal axis and a second real image point in a second cross-section of the transverse axis. The first real image point and the second real image point are image conjugates of the virtual object point. The virtual object point, the first real image point and the second real image point coincide.

A source selection module for spectrally shaping a broadband illumination beam to obtain a spectrally shaped illumination beam. The source selection module includes a beam dispersing element for dispersing the broadband illumination beam; a grating light valve module for spatially modulating the broadband illumination beam subsequent to being dispersed; and a beam combining element to recombine the spatially modulated broadband illumination beam to obtain an output source beam.

Displacement measurement systems, measurement methods and EUV lithography machines for quantum meta-structure elements are disclosed, which include: an entangled state light source generator, a meta-device, a collimating lens, a polarizing beam splitter, and a computing section. Left-rotation photon and the right-rotation photon are projected to the polarizing beam splitter, and the correlation between output ports of two polarizing beam splitters is counted for reading to measure the displacement of the meta-device element. The displacement of the meta-structure element is measured in a manner that realizes the correlation between the left-rotation photons and the right-rotation photons.

An aperture for detecting a laser beam misalignment, the aperture comprising: a body including a first opening and defining a first axis; a beam dump; an optical element including a second opening wherein the first opening and the second opening are coaxial with the first axis, the optical element being configured to redirect a misaligned laser beam to a detector or to split a misaligned laser beam into at least two sub-beams; a laser beam detection system configured to detect laser light, wherein the optical element is configured to direct a first sub-beam to the beam dump, and to direct a second sub-beam to the laser beam detection system. Also described is an aperture including an enclosure, a method of detecting misalignment of a laser beam, a radiation source comprising such an aperture, a lithographic apparatus comprising such a radiation source or aperture, and the use of the same in a lithographic apparatus or method.

Systems, methods, and media for determining a processing parameter associated with a lithography process. In some embodiments, image data of features on a substrate may be obtained, and the image data may be analyzed in Fourier space. Based on the analysis, an amplitude and a phase may be determined, and an overlay of the features may be determined based on the amplitude and the phase.

A supercontinuum radiation source including a pump laser arrangement for generating pump radiation and including a plurality of pump laser heads; a radiation combiner for combining the respective pump radiation from each pump laser head, and a non-linear fiber for receiving the pump radiation so as to excite a working medium within the non-linear fiber to generate supercontinuum radiation. Each pump laser head has dimensions no greater than 5 cm in any direction. Alternatively, or in addition the supercontinuum radiation source further includes a control arrangement for controlling the pump laser arrangement, the control arrangement configured for non-simultaneous emission of pulses from each pump laser head.

A measurement optical system and an overlay measurement method using the same are provided. The measurement optical system includes: a light source configured to emit infrared light; a light splitter configured to reflect, from the light source and to a subject, a first portion of the infrared light incident to the light splitter; a photodetector on a same optical axis as the light splitter and configured to receive a second portion of the infrared light reflected from the subject; a first lens optical system between the light splitter and the photodetector; and a second lens optical system between the first lens optical system and the photodetector, wherein the subject may include an alignment key on which a meta key is provided.

An inspection system, a lithographic apparatus, and a method are provided. The inspection system includes an illumination system, an optical system, a shutter system, an objective system and a detector. The illumination system is configured to generate an illumination beam. The optical system is configured to split the illumination beam into a first sub-beam and a second sub-beam. The shutter system is configured to independently control a transmittance of the first sub-beam and the second subbeam. The objective system is configured to receive the first sub-beam and the second beam from the optical system and direct the first sub-beam and the second sub-beam towards a substrate having a target structure. The detector is configured to receive an image or a diffracted image of the target structure.

Displacement measurement systems, measurement methods and EUV lithography machines for quantum meta-structure elements are disclosed, which include: an entangled state light source generator, a meta-device, a collimating lens, a polarizing beam splitter, and a computing section. Left-rotation photon and the right-rotation photon are projected to the polarizing beam splitter, and the correlation between output ports of two polarizing beam splitters is counted for reading to measure the displacement of the meta-device element. The displacement of the meta-structure element is measured in a manner that realizes the correlation between the left-rotation photons and the right-rotation photons.

Disclosed is a method of correcting a measured spectrum for the effects of a source spectrum resulting from an illumination source. The method comprises obtaining a measured spectrum in terms of a measurement parameter, the measured spectrum being obtained from captured diffracted radiation from a periodic structure following illumination of said periodic structure using source radiation from said illumination source, the periodic structure being the spectrometer grating and an object being measured; determining an estimate of the source spectrum from the measured spectrum; and correcting the measured spectrum using the estimate of the source spectrum.