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.

Described embodiments include a system for inspecting a tubular device that includes an outer surface and a spatially-periodic supporting structure beneath the outer surface. The system includes an imaging device, configured to acquire an image of a reflection of light from the outer surface, and a processor, configured to ascertain a spatial frequency of the supporting structure by processing the image. Other embodiments are also described.

An optical system and method are presented for use in measurements on an upper surface of a layered sample when located in a measurement plane. The optical system is configured as a normal-incidence system having an illumination channel and a collection channel, and comprises an objective lens unit and a light propagation affecting device. The objective lens unit is accommodated in the illumination and collection channels, thereby defining a common optical path for propagation of illuminating light from the illumination channel toward an illuminating region in the measurement plane and for propagation of light returned from measurement plane to the collection channel. The light propagation affecting device comprises an apertured structure located in at least one of the illumination and collection channels, and configured to provide angular obscuration of light propagation path for blocking angular segments associated with light propagation from regions outside the illuminated region.

An optical system includes an illumination module configured to illuminate a sample object with at least one angle-variable illumination geometry. The optical system includes an imaging optical unit configured to produce an imaged representation of the sample object that is illuminated with the at least one angle-variable illumination geometry on a detector. The optical system includes the detector, which is configured to capture at least one image of the sample object based on the imaged representation. The optical system includes a controller configured to determine a result image based on a transfer function and the at least one image. A method includes illuminating a sample object with at least one angle-variable illumination geometry, imaging the sample object on a detector, based on the imaged representation, capturing at least one image of the sample object, and, based on a transfer function and the at least one image, determining a result image.

Disclosed is a method for a metrology measurement on an area of a substrate comprising at least a portion of a target structure. The method comprises receiving a radiation information representing a portion of radiation scattered by the are, and using a filter in a Fourier domain for removing or suppressing at least a portion of the received radiation information that does not relate to radiation that has been scattered by the target structure for obtaining a filtered radiation information for the metrology measurement, wherein characteristics of the filter are based on target information about the target structure.

An optical inspection system includes one or more gratings to convert the polarization of light scattered from a target from an elliptical polarization that varies spatially across a collection pupil to a linear polarization that is uniformly oriented across the collection pupil. The one or more gratings have phase retardation that varies spatially across the collection pupil in accordance with the elliptical polarization. The one or more gratings include at least one grating on a reflective substrate. The optical inspection system also includes a linear polarizer to filter out the linearly polarized light.

Provided are a defect observation method and a defect observation device which detect a defect from an image obtained by imaging the defect on a sample with an optical microscope by using positional information of the defect on the sample detected by a different inspection device to correct the positional information of the defect and observe in detail the defect on the sample with a scanning electron microscope using the corrected positional information. The defect observation method includes detecting the defect from the image to correct the positional information of the defect, switching a spatially-distributed optical element of a detection optical system of the optical microscope according to the defect to be detected, and changing an image acquisition condition for acquiring the image and an image processing condition for detecting the defect from the image according to a type of the switched spatially-distributed optical element.

Provided is a sample property detecting apparatus including: a wave source configured to irradiate a wave towards a sample; a detector configured to detect a laser speckle that is generated when the wave is multiple-scattered by the sample, at every time point that is set in advance; and a controller configured to obtain a temporal correlation that is a variation in the detected laser speckle according to time, and to detect properties of the sample in real-time based on the temporal correlation, wherein the detector detects the laser speckle between the sample and the detector or from a region in the detector.

A system that may include a radiation source to generate a beam of coherent radiation; traveling lens optics to focus the beam so as to generate multiple spots on a surface of a sample and to scan the spots together over the surface; collection optics to collect the radiation scattered from the multiple spots and to focus the collected radiation so as to generate a pattern of interference fringes; and a detection unit to detect changes in the pattern of interference fringes.

A metrology system includes an illumination source configured to generate an illumination beam, one or more illumination optics configured to direct the illumination beam to a sample, one or more collection optics configured to collect illumination emanating from the sample, a detector, and a hyperspectral imaging sub-system. The hyperspectral imaging sub-system includes a dispersive element positioned at a pupil plane of the set of collection optics configured to spectrally disperse the collected illumination, a lens array including an array of focusing elements, and one or more imaging optics. The one or more imaging optics combine the spectrally-dispersed collected illumination to form an image of the pupil plane on the lens array. The focusing elements of the lens array distribute the collected illumination on the detector in an arrayed pattern.