Abstract: A system (400) includes an illumination system (402), a detector (404), and a comparator (406). The illumination system includes a radiation source (408) and a spatial light modulator (410). The radiation source generates a beam of radiation (442). The spatial light modulator directs the beam toward a surface (436) of an object (428) and adjusts a spatial intensity distribution of the beam at the surface. The detector receives radiation (444) scattered at the surface and by a structure (434) near the surface. The detector generates a detection signal based on the received radiation. The comparator receives the detection signal, generates a first image based on the detection signal, and distinguishes between a spurious signal and a signal corresponding to a presence of a foreign particle on the surface based on the first image and the adjusted spatial intensity distribution.

Abstract: A system (400) includes an illumination system (402), a detector (404), and a comparator (406). The illumination system includes a radiation source (408) and a spatial light modulator (410). The radiation source generates a beam of radiation (442). The spatial light modulator directs the beam toward a surface (436) of an object (428) and adjusts a spatial intensity distribution of the beam at the surface. The detector receives radiation (444) scattered at the surface and by a structure (434) near the surface. The detector generates a detection signal based on the received radiation. The comparator receives the detection signal, generates a first image based on the detection signal, and distinguishes between a spurious signal and a signal corresponding to a presence of a foreign particle on the surface based on the first image and the adjusted spatial intensity distribution.

Abstract: Methods and apparatus for determining a parameter of a structure fabricated in or on a substrate and compensated for a drift error. The methods comprising: illuminating, at a plurality of times, at least part of the structure with electromagnetic radiation, the at least part of the structure being at a first orientation; sensing, at the plurality of times, a plurality of average reflectances of the at least part of the structure; and determining, based on the plurality of average reflectances, an estimation of the parameter at one or more further times.

Abstract: Disclosed is a method of metrology. The method comprises illuminating a radiation onto a substrate; obtaining measurement data relating to at least one measurement of each of one or more structures on the substrate; using a Fourier-related transform to transform the measurement data into a transformed measurement data; and extracting a feature of the substrate from the transformed measurement data, or eliminating an impact of a nuisance parameter.

Abstract: A grating is provided on a mirror for specularly reflecting and diffracting a grazing-incidence beam of radiation and has a periodic structure with a grating period comprising first (ridge) and second (trench) substructures either side of a sidewall 806 facing the incident beam 800. The ridge is configured to specularly reflect the beam from the flat top 808 of the ridge into a specularly reflected beam 810 in a zeroth-order direction ??=?. The grating is configured with fixed or varying pitch to diffract the beam from the grating periods in one or more non-zero-diffraction-order direction ????. The shape of the trench may be is described by structural parameters top width and depth that define the aspect ratio of the trench. The shape is determined such that any rays (and optionally diffraction) of the beam that reflect once from the trench floor in the zeroth-order direction are obscured by the sidewall.

Abstract: Methods and apparatus for determining an intensity profile of a radiation beam. The method comprises providing a diffraction structure, causing a relative movement of the diffraction structure relative to the radiation beam from a first position, wherein the radiation beam does not irradiate the diffraction structure to a second position, wherein the radiation beam irradiates the diffraction structure, measuring, with a radiation detector, diffracted radiation signals produced from a diffraction of the radiation beam by the diffraction structure as the diffraction structure transitions from the first position to the second position or vice versa, and determining an intensity profile of the radiation beam based on the measured diffracted radiation signals.

Abstract: Designs are provided to reduce the possibility of contaminant particles with a large range of sizes, materials, travel speeds and angles of incidence reaching a particle-sensitive environment. According to an aspect of the disclosure, there is provided an object stage comprising first and second chambers, a first structure having a first surface, and a second structure. The second structure is configured to support an object in the second chamber, movable relative to the first structure. The second structure comprises a second surface opposing the first surface of the first structure thereby defining a gap between the first structure and the second structure that extends between the first chamber and the second chamber. The second structure further comprises a third surface within the first chamber. The object stage further comprises a trap disposed on at least a portion of the third surface, the trap comprising a plurality of baffles.

Abstract: A radiation source comprises: an emitter for emitting a fuel target towards a plasma formation region; a laser system for hitting the target with a laser beam to generating a plasma; a collector for collecting radiation emitted by the plasma; an imaging system configured to capture an image of the target; one or more markers at the collector and within a field of view of the imaging system; and a controller. The controller receives data representative of the image; and controls operation of the radiation source in dependence on the data.

Abstract: A lithographic apparatus that includes an illumination system that conditions a radiation beam, a first stationary plate having a first surface, and a reticle stage defining, along with the first stationary plate, a first chamber. The reticle stage supports a reticle in the first chamber, and the reticle stage includes a first surface spaced apart from a second surface of the first stationary plate, thereby defining a first gap configured to suppress an amount of contamination passing from a second chamber to the first chamber. The first stationary plate is between the reticle stage and both the illumination system and a projection system configured to project a pattern imparted to the radiation beam by the patterning device onto a substrate.

Abstract: A beam-splitting apparatus arranged to receive an input radiation beam and split the input radiation beam into a plurality of output radiation beams. The beam-splitting apparatus comprising a plurality of reflective diffraction gratings arranged to receive a radiation beam and configured to form a diffraction pattern comprising a plurality of diffraction orders, at least some of the reflective diffraction gratings being arranged to receive a 0th diffraction order formed at another of the reflective diffraction gratings. The reflective diffraction gratings are arranged such that the optical path of each output radiation beam includes no more than one instance of a diffraction order which is not a 0th diffraction order.

Abstract: The disclosure relates to measuring a parameter of a lithographic process and a metrology apparatus. In one arrangement, radiation from a radiation source is modified and used to illuminate a target formed on a substrate using the lithographic process. Radiation scattered from a target is detected and analyzing to determine the parameter. The modification of the radiation comprises modifying a wavelength spectrum of the radiation to have a local minimum between a global maximum and a local maximum, wherein the power spectral density of the radiation at the local minimum is less than 20% of the power spectral density of the radiation at the global maximum and the power spectral density of the radiation at the local maximum is at least 50% of the power spectral density of the radiation at the global maximum.

Abstract: Disclosed is a method and associated inspection apparatus for detecting variations on a surface of a substrate. The method comprises providing patterned inspection radiation to a surface of a substrate. The inspection radiation is patterned such that an amplitude of a corresponding enhanced field is modulated in a manner corresponding to the patterned inspection radiation. The scattered radiation resultant from interaction between the enhanced field and the substrate surface is received and variations on the surface of the substrate are detected based on the interaction between the enhanced field and the substrate surface. Also disclosed is a method of detecting any changes to at least one characteristic of received radiation, the said changes being induced by the generation of a surface plasmon at said surface of the optical element.

Abstract: A lithographic apparatus that includes an illumination system that conditions a radiation beam, a first stationary plate having a first surface, and a reticle stage defining, along with the first stationary plate, a first chamber. The reticle stage supports a reticle in the first chamber, and the reticle stage includes a first surface spaced apart from a second surface of the first stationary plate, thereby defining a first gap configured to suppress an amount of contamination passing from a second chamber to the first chamber. The first stationary plate is between the reticle stage and both the illumination system and a projection system configured to project a pattern imparted to the radiation beam by the patterning device onto a substrate.

Abstract: A measurement system to determine a deformation of an object having a front surface, a back surface and a pattern. The measurement system includes a processor system and an interferometer system. The interferometer system has a radiation source and a detector system. The source is configured to emit, to each of a plurality of locations on the object, measurement beams in order to generate, at each of the respective plurality of locations, reflected measurement beams off the front and back surfaces of the object respectively. The detector system is configured to receive the respective reflected measurement beams and output signals representative of the received reflected measurement beams to the processor system. The processor system is configured to receive the signals; determine, based on the signals as received, a characteristic of the object; and determine a deformation of the pattern based on the characteristic.

Abstract: A radiation sensor apparatus for determining a position and/or power of a radiation beam, the radiation sensor apparatus including a chamber to contain a gas, one or more sensors, and a processor. The chamber has a first opening and a second opening such that a radiation beam can enter the chamber through the first opening, propagate through the chamber generally along an axis, and exit the chamber through the second opening. Each of the one or more sensors is arranged to receive and detect radiation emitted from a region of the chamber around the axis. The processor is operable to use the radiation detected by the one or more sensors to determine a position and/or power of the radiation beam.

Abstract: A measurement system to determine a deformation of an object having a front surface, a back surface and a pattern. The measurement system includes a processor system and an interferometer system. The interferometer system has a radiation source and a detector system. The source is configured to emit, to each of a plurality of locations on the object, measurement beams in order to generate, at each of the respective plurality of locations, reflected measurement beams off the front and back surfaces of the object respectively. The detector system is configured to receive the respective reflected measurement beams and output signals representative of the received reflected measurement beams to the processor system. The processor system is configured to receive the signals; determine, based on the signals as received, a characteristic of the object; and determine a deformation of the pattern based on the characteristic.

Abstract: A radiation source comprises: an emitter for emitting a fuel target towards a plasma formation region; a laser system for hitting the target with a laser beam to generating a plasma; a collector for collecting radiation emitted by the plasma; an imaging system configured to capture an image of the target; one or more markers at the collector and within a field of view of the imaging system; and a controller. The controller receives data representative of the image; and controls operation of the radiation source in dependence on the data.

Abstract: An optical system (OS) for focusing a beam of radiation (B) on a region of interest in a metrology apparatus is described. The beam of radiation (B) comprises radiation in a soft X-ray or Extreme Ultraviolet spectral range. The optical system (OS) comprises a first stage (S1) for focusing the beam of radiation at an intermediate focus region. The optical system (OS) comprises a second stage (S2) for focusing the beam of radiation from the intermediate focus region onto the region of interest. The first and second stages each comprise a Kirkpatrick-Baez reflector combination. At least one reflector comprises an aberration-correcting reflector.

Abstract: Designs are provided to reduce the possibility of contaminant particles with a large range of sizes, materials, travel speeds and angles of incidence reaching a particle-sensitive environment. According to an aspect of the disclosure, there is provided an object stage comprising first and second chambers, a first structure having a first surface, and a second structure. The second structure is configured to support an object in the second chamber, movable relative to the first structure. The second structure comprises a second surface opposing the first surface of the first structure thereby defining a gap between the first structure and the second structure that extends between the first chamber and the second chamber. The second structure further comprises a third surface within the first chamber. The object stage further comprises a trap disposed on at least a portion of the third surface, the trap comprising a plurality of baffles.

Abstract: The disclosure relates to measuring a parameter of a lithographic process and a metrology apparatus. In one arrangement, radiation from a radiation source is modified and used to illuminate a target formed on a substrate using the lithographic process. Radiation scattered from a target is detected and analyzing to determine the parameter. The modification of the radiation comprises modifying a wavelength spectrum of the radiation to have a local minimum between a global maximum and a local maximum, wherein the power spectral density of the radiation at the local minimum is less than 20% of the power spectral density of the radiation at the global maximum and the power spectral density of the radiation at the local maximum is at least 50% of the power spectral density of the radiation at the global maximum.