Abstract: The invention provides a level sensor configured to determine a height level of a surface of a substrate, comprising a detection unit arranged to receive a measurement beam after reflection on the substrate, wherein the detection unit comprises an array of detection elements, wherein each detection element is arranged to receive a part of the measurement beam reflected on a measurement subarea of the measurement area, and is configured to provide a measurement signal based on the part of the measurement beam received by the respective detection element, and wherein the processing unit is configured to calculate, in dependence of a selected resolution at the measurement subarea, a height level of the measurement subarea, or to calculate a height level of a combination of multiple measurement subareas.

Abstract: An “angle-resolved” version of FD-OCT is used to measure reflectance properties. An inspection apparatus comprises an illumination source configured to provide an illumination beam, an interferometer configured to use the illumination beam to illuminate a target on a substrate at an incidence angle and to use radiation reflected from the substrate with a reference beam derived from the illumination beam to produce an output beam, a sampling device arranged to select a portion of the output beam, a spectrometer configured to receive the selected portion of the output beam and to measure a spectrum of the received selected portion of the output beam, and a processor configured to determine from the measured spectrum reflectance properties of the target such as raw spectrometer spectral data, the Fourier transformed data, the extracted intensity components or carrier phase or the calculated complex reflectance.

Abstract: A level sensor for measuring a position of a surface of a substrate includes a projection unit including an emitter for emitting a radiation beam towards the substrate and a projection grating including a measurement grating and an aperture, such that the radiation beam incident on the projection grating is divided into a measurement radiation beam and a capture radiation beam. The level sensor further includes a detection unit including a first and second measurement detector, a first and second capture detector, a detection grating, and a first and second optical unit. The detection grating includes a ruled grating with multiple rules, which direct radiation towards the first and second measurement detector via the first and second optical unit, and a capture element directing radiation towards the first and second capture detector via the first and second optical unit.

Abstract: A self-referencing interferometer includes an optical system to split an alignment beam to create a reference beam and a transformed beam. The optical system includes a beam splitter to combine the reference beam and the transformed beam so that the diffraction orders in the reference beam spatially overlap with their respective opposite orders in the transformed beam. A detector system receives the spatially overlapping reference beam and transformed beam from the optical system and determines a position signal. The detector system includes a polarizing system for manipulating the polarization of the beams so that they interfere, and for directing the interfering reference beam and transformed beam to a detector for determining a position signal from the variation of intensity of the interfering beams.

Abstract: A lithographic apparatus is arranged to transfer a pattern from a patterning device onto a substrate, in which a measuring subsystem includes one or (preferably) more alignment & level sensors (AS, LS) directed at the substrate near a patterning location of a patterning subsystem. The alignment sensor(s) is operable to recognize and measure alignment marks (P1) on the substrate passing by the sensor during relative motion of the substrate and patterning subsystem under control of the positioning subsystem. A processor combines measurements of relative locations of a plurality of said marks to provide measurement results with an accuracy sufficient for the positioning subsystem to position at least a first substrate portion at said patterning location relative to said alignment marks. A preliminary step obtains position relative to a known pattern (M1) on the patterning device. Measurements are taken and updated in real time during exposure of successive substrate portions.

Abstract: A level sensor for measuring a position of a surface of a substrate includes a projection unit including an emitter for emitting a radiation beam towards the substrate and a projection grating including a measurement grating and an aperture, such that the radiation beam incident on the projection grating is divided into a measurement radiation beam and a capture radiation beam. The level sensor further includes a detection unit including a first and second measurement detector, a first and second capture detector, a detection grating, and a first and second optical unit. The detection grating includes a ruled grating with multiple rules, which direct radiation towards the first and second measurement detector via the first and second optical unit, and a capture element directing radiation towards the first and second capture detector via the first and second optical unit.

Abstract: An “angle-resolved” version of FD-OCT is used to measure reflectance properties. An inspection apparatus comprises an illumination source configured to provide an illumination beam, an interferometer configured to use the illumination beam to illuminate a target on a substrate at an incidence angle and to use radiation reflected from the substrate with a reference beam derived from the illumination beam to produce an output beam, a sampling device arranged to select a portion of the output beam, a spectrometer configured to receive the selected portion of the output beam and to measure a spectrum of the received selected portion of the output beam, and a processor configured to determine from the measured spectrum reflectance properties of the target such as raw spectrometer spectral data, the Fourier transformed data, the extracted intensity components or carrier phase or the calculated complex reflectance.

Abstract: A self-referencing interferometer includes an optical system to split an alignment beam to create a reference beam and a transformed beam. The optical system includes a beam splitter to combine the reference beam and the transformed beam so that the diffraction orders in the reference beam spatially overlap with their respective opposite orders in the transformed beam. A detector system receives the spatially overlapping reference beam and transformed beam from the optical system and determines a position signal. The detector system includes a polarizing system for manipulating the polarization of the beams so that they interfere, and for directing the interfering reference beam and transformed beam to a detector for determining a position signal from the variation of intensity of the interfering beams.

Abstract: A lithographic apparatus is arranged to transfer a pattern from a patterning device onto a substrate, in which a measuring subsystem comprises one or (preferably) more alignment & level sensors (AS, LS) directed at the substrate near a patterning location of a patterning subsystem. The alignment sensor(s) is operable to recognize and measure alignment marks (P1) on the substrate passing by the sensor during relative motion of the substrate and patterning subsystem under control of the positioning subsystem. A processor combines measurements of relative locations of a plurality of said marks to provide measurement results with an accuracy sufficient for the positioning subsystem to position at least a first substrate portion at said patterning location relative to said alignment marks. A preliminary step obtains position relative to a known pattern (M1) on the patterning device. Measurements are taken and updated in real time during exposure of successive substrate portions.

Abstract: The invention provides a level sensor configured to measure a height level of a substrate comprising: a projection unit to project a measurement beam on the substrate, a detection unit to receive the measurement beam after reflection on the substrate, a processing unit to calculate a height level on the basis of the reflected measurement beam received by the detection unit, wherein the level sensor further comprises a tilt measuring device, wherein the tilt measuring device is arranged to receive at least partially the reflected measurement beam, and configured to provide a tilt signal representative for a tilt of the substrate with respect to a nominal plane.