The invention provides an inspection apparatus for inspecting an object, the apparatus comprising: a measurement system configured to measure: —a first parameter of the object across an area of interest of the object, and —a second parameter, different from the first parameter, of the object at a plurality of locations on the object; a stage apparatus configured to position the object relative to the measurement system during a measurement of the first parameter, wherein the measurement system is configured to measure the second parameter at the plurality of different locations during the measurement of the first parameter and wherein the stage apparatus is configured to position the object relative to the measurement system based on a compliance characteristic of the stage apparatus.

A broadband radiation source device configured for generating a broadband output radiation upon receiving pump radiation, the device including: a hollow-core photonic crystal fiber (HC-PCF) including at least one structurally varied portion having at least one structural parameter of the HC-PCF varied with respect to one or more main portions of the HC-PCF, wherein the at least one structurally varied portion includes at least a structurally varied portion located downstream of a position along the length of the HC-PCF where the pump radiation will be spectrally expanded by a modulation instability dominated nonlinear optical process, and wherein the at least one structurally varied portion is configured and located such that the broadband output radiation includes wavelengths in the ultraviolet region.

A method to reduce sensitivity of a level sensor, arranged to measure a height of a substrate, to variations of a property of an optical component in the level sensor includes directing a beam of radiation toward a diffractive element and directing the beam, via an optical system, to a first reflective element at a first angle of incidence. The beam has a first polarization and a second polarization that is perpendicular to the first polarization. The first reflective element reflects the beam toward a second reflective element at a second angle of incidence causing the beam to impinge on the substrate. The first and second angles of incidence are selected to reduce variations of a ratio of intensities of the first polarization to the second polarization of the beam imparted by a property of a layer of at least one of the first and second reflective elements.

An apparatus comprising: a position monitoring system configured to determine the position of the substrate with respect to a projection system configured to project a radiation beam through an opening in the projection system and onto a substrate, wherein a component of the position monitoring system is located beneath the projection system in use; and a baffle disposed between the opening and the component.

The present invention provides a method for calculating a corrected substrate height map of a first substrate using a height level sensor. The method comprises: sampling the first substrate by means of the height level sensor with the first substrate moving with a first velocity, wherein the first velocity is a first at least partially non-constant velocity of the first substrate with respect to the height level sensor, to generate a first height level data, generating a first height map based on the first height level data, and calculating a corrected substrate height map by subtracting a correction map from the first height map, wherein the correction map is calculated from the difference between a first velocity height map and a second velocity height map.

The present invention provides a method to obtain a height map of a substrate having alignment marks, the method comprising the steps: determining a height of one or more locations or areas of the substrate, and determining the height map of the substrate on the basis of the determined height of the one or more locations or areas of the substrate and a shape model of the substrate.

A supercontinuum radiation source including a modulator being operable to modulate pump laser radiation including a train of radiation pulses to provide modulated pump laser radiation, the modulation being such to selectively provide a burst of the pulses; and a hollow-core photonic crystal fiber being operable to receive the modulated pump laser radiation and excite a working medium contained within the hollow-core photonic crystal fiber so as to generate supercontinuum radiation.

Methods and associated apparatus for reconstructing a free-form geometry of a substrate, the method including: positioning the substrate on a substrate holder configured to retain the substrate under a retaining force that deforms the substrate from its free-form geometry; measuring a height map of the deformed substrate; and reconstructing the free-form geometry of the deformed substrate based on an expected deformation of the substrate by the retaining force and the measured height map.

A distance sensor (1) for estimating a distance to a surface (OS) of an object (O), the distance sensor including a micro electric mechanical system (MEMS) (5), a detection means (30) and a processing device (40). The MEMS comprises a MEMS device (10) having a surface (12), denoted as MEMS sensor surface, to be arranged opposite the surface (OS) of said object (O) and a MEMS driver (20) for generating an ac driving signal to cause the MEMS sensor surface (12) to vibrate. The detection means (30) is to determine a value of a property of a dynamic behavior of the MEMS (5) and the processing device (40) is to estimate an average distance (h) as a measured distance (D2) between the MEMS sensor surface (12) and the surface (Os) of the object (O) based on the determined value for said property.

The invention provides a level sensor to measure a position of a surface of a substrate, comprising a projection unit arranged to direct a beam of radiation to the surface of the substrate and a detection unit. The detection unit comprises a detection grating arranged to receive the beam of radiation reflected on the surface of the substrate, one or more detectors, one or more optical elements to direct the beam of radiation from the detection grating to the one or more detectors, and a processing unit to determine the position of the surface of the substrate on the basis of the beam of radiation received by the one or more detectors. The detection grating and the one or more optical elements are integrated in a single integrated optical element.