A method of generating broadband output radiation and associated broadband radiation source. The method includes generating pulses of input radiation having a duration between 50 fs and 400 fs and having a rise time of less than 60 fs; and exciting a working medium within a hollow core fiber with the pulses of input radiation.

A substrate inspection apparatus includes a light irradiator including an objective lens and a plurality of optical fibers. The objective lens is configured to irradiate light to an illumination area on a semiconductor substrate having a plurality of circuit pattern layers, the plurality of optical fibers are adjacent a periphery of the objective lens and are configured to irradiate the light to a peripheral area adjacent the illumination area. A light generator is configured to generate the light. The light generator is configured to change an irradiation angle of the light to selectively irradiate the light to one or more of the objective lens and the plurality of optical fibers. A light analyzer is configured to obtain images of the circuit pattern layers from the light reflected from the illumination area and the peripheral area. The light analyzer is configured to model each of the circuit pattern layers of the semiconductor substrate to obtain image models and to measure an overlay between the circuit pattern layers through the images and the image models.

An overlay metrology system may include a collection sub-system with an objective lens and detector located at a pupil plane. The system may include an illumination sub-system with illumination optics to direct one or more broadband illumination beams to an overlay target on a sample at incidence angles outside a numerical aperture of the objective lens, where the overlay target includes one or more cells having periodic features formed grating-over-grating structures. The system may further include a controller to receive pupil images of the cells from the detector, where a respective one of the one or more pupil images include first-order diffraction from at least one of the one or more broadband illumination beams, wherein spectra of the first-order diffraction is spectrally dispersed in the pupil plane. The controller may further generate an overlay measurement of the sample based on selected portions of the one or more pupil images.

A beam metrology device for determining at least one characteristic of first radiation and/or at least one characteristic of second radiation, said second radiation being generated via a first nonlinear process upon receiving a first portion of the first radiation; the beam metrology device comprising: a metrology device nonlinear medium configured to receive a second portion of the first radiation and thereby to generate third radiation via a second nonlinear process; at least one detector configured to measure at least one characteristic of the third radiation; and a processing unit operable to determine the at least one characteristic of the first radiation and/or the at least one characteristic of the second radiation based on said at least one characteristic of the third radiation.

An inspection system includes a radiation source, first and second optical structures, and a detection system. The radiation source generates beams of radiation. An image formed by the beams includes radiation spots corresponding to the beams. Diameters of the radiation spots is less than a dimension of a target and the radiation spots are non-overlapping. The first optical structure routes the beams toward the target so as to project the radiation spots on the target and generate scattered radiation from the target. The second optical structure collects the scattered radiation from the target. The detection system receives the scattered radiation collected by the second optical structure and generates measurement signals. Each of the measurement signals corresponds to each of the radiation spots.

Disclosed is a metrology method. The method comprises illuminating a target comprising one or more sub-targets on a substrate using underfilled illumination such that an illumination beam profile underfills each of said one or more sub-targets; capturing scattered radiation resultant from said illuminating the target; imaging the scattered radiation at a detection image plane to obtain an image; and determining a parameter of interest from the imaged scattered radiation.

Disclosed is a method of determining an orthonormalized structure of interest reference image. the orthonormalized structure of interest reference image for applying to a measured image of the structure of interest to correct for the effect of crosstalk from at least one nuisance structure. The method comprises determining a structure of interest reference image based on knowledge of the structure of interest; determining at least one nuisance structure reference image based on knowledge of the at least one nuisance structure; and orthonormalizing the structure of interest reference image to the at least one nuisance reference image to obtain the orthonormalized structure of interest reference image.

A method including: obtaining a detected representation of radiation redirected by each of a plurality of structures from a substrate additionally having a device pattern thereon, wherein each structure has an intentional different physical configuration of the respective structure than the respective nominal physical configuration of the respective structure, wherein each structure has geometric symmetry at the respective nominal physical configuration, wherein the intentional different physical configuration of the structure causes an asymmetric optical characteristic distribution and wherein a patterning process parameter measures change in the physical configuration; and determining a value, based on the detected representations and based on the intentional different physical configurations, to setup, monitor or correct a measurement recipe for determining the patterning process parameter.

A method of determining a parameter of interest of a structure comprising at least one first feature oriented along a first axis of a structure coordinate system and at least one second feature oriented along a second axis of the structure coordinate system. The method comprising: illuminating the first feature and the second feature with first illumination from a first direction oblique to said first axis and second axis, so as to generate first scattered radiation from the first feature and second scattered radiation from the second feature, detecting a first interference pattern formed by interference between a portion of the first scattered radiation and first reference illumination; detecting a second interference pattern formed by interference between a portion of the second scattered radiation and the first reference illumination; and determining the parameter of interest of the structure using the first interference pattern and the second interference pattern.

A lithography mask may include a substrate layer. The lithography mask may include a multilayer reflective film disposed on the substrate layer and forming a first pattern, wherein the multilayer reflective film is configured to receive incident light and reflect a portion of the incident light toward an imaging collection pupil. The lithography mask may include a grating forming a second pattern on the substrate layer and configured to receive the incident light and deflect an additional portion of the incident light outside of the imaging collection pupil. The lithography mask may be inspected by an Actinic Patterned Mask Inspection (APMI) system. The second pattern may include a reflective film deposited on the grating.