Abstract: A sample mapping system includes a sample chuck including absolute reference marks, an imaging metrology tool to capture sets of alignment images at locations associated with sample marks on a sample on the sample chuck, and a controller. A particular set of alignment images at a particular location may include at least one alignment image associated with a particular sample mark and at least one alignment image associated with a particular portion of the absolute reference marks within a field of view of the imaging metrology tool visible through the sample. The controller may determine absolute coordinates of the sample marks based on the sets of alignment images. Determining the absolute coordinates of the particular sample mark may include determining the absolute coordinates of the particular sample mark based on a position of the particular sample mark relative to the particular portion of the absolute reference marks.

Abstract: A method for imaging overlay targets on a wafer includes (1) using a sensor to acquire images of overlay targets on a wafer while the wafer is in motion and (2) accelerating and decelerating the wafer to move the overlay targets into alignment with the sensor between acquiring images of the overlay targets. Accelerating/decelerating the wafer may include: (1) accelerating the wafer at a maximum acceleration and then decelerating the wafer at a maximum deceleration, (2) accelerating/decelerating the wafer in a triangular waveform pattern, (3) accelerating/decelerating the wafer in a sinusoidal pattern, or (4) accelerating/decelerating the wafer in a near-sinusoidal pattern (created by combining a pure sinusoidal profile with one or more harmonic profiles). A system is also provided for implementing the above method(s).

Abstract: A metrology tool may include an illumination sub-system to illuminate sample within two or more acquisition fields with two or more illumination beams, where the two or more acquisition fields are distributed along a scan direction in a non-overlapping configuration, and where a translation stage translates a metrology target on the sample along the scan direction sequentially through the two or more acquisition fields. The metrology tool may further include an imaging sub-system to image the two or more acquisition fields while the sample is scanned along the scan direction. The imaging sub-system may include a field-repositioning optical relay to relay images of the two or more acquisition fields to a scanning detector including one or more pixel columns distributed along a column direction, where the field-repositioning optical relay positions the images of the two or more acquisition fields on the scanning detector along the column direction.

Abstract: An overlay metrology system may include an illumination sub-system to sequentially illuminate an overlay target with a first illumination lobe and a second illumination lobe opposite the first illumination lobe, where the overlay target includes grating-over-grating features formed from periodic structures on a first sample layer and a second sample layer. The system may further include an imaging sub-system to generate a first image and a second image of the overlay target. The first image includes an unresolved image of the grating-over-grating structures formed from a single non-zero diffraction order of the first illumination lobe. The second image includes an unresolved image of the one or more grating-over-grating structures formed from a single non-zero diffraction order of the second illumination lobe. The system may further include a controller to determine an overlay error between the first layer and the second layer based on the first image and the second image.

Abstract: An overlay metrology system may include an illumination sub-system to sequentially illuminate an overlay target with a first illumination lobe and a second illumination lobe opposite the first illumination lobe, where the overlay target includes grating-over-grating features formed from periodic structures on a first sample layer and a second sample layer. The system may further include an imaging sub-system to generate a first image and a second image of the overlay target. The first image includes an unresolved image of the grating-over-grating structures formed from a single non-zero diffraction order of the first illumination lobe. The second image includes an unresolved image of the one or more grating-over-grating structures formed from a single non-zero diffraction order of the second illumination lobe. The system may further include a controller to determine an overlay error between the first layer and the second layer based on the first image and the second image.

Abstract: A metrology system may include an illumination sub-system to illuminate a metrology target on a sample with illumination having a symmetric off-axis illumination profile, where the symmetric off-axis illumination profile is symmetric along one or more measurement directions, and where the illumination sub-system provides illumination from opposing angles in the symmetric off-axis illumination profile at least one of simultaneously or sequentially. The metrology target may include a first periodic structure on a first layer of the sample and a second periodic structure on a second layer of the sample. The metrology system may further include an imaging sub-system to generate images of the metrology target formed using two non-zero diffraction orders from each point of the symmetric off-axis illumination profile. The metrology subsystem may further determine an overlay error indicative of alignment between the first layer and the second layer based on the one or more images.

Abstract: An overlay metrology tool may include an illumination source, illumination optics to illuminate an overlay target having periodic features with one or more illumination beams, collection optics to direct diffracted light from the periodic features of the overlay target to a detector, an adjustable pupil mask located at a pupil plane, and a controller. The adjustable pupil mask may include one or more individually-addressable control zones distributed across the one or more portions of the pupil plane to provide an adjustable pupil transmissivity distribution. The controller may direct the adjustable pupil mask to provide a selected pupil transmissivity distribution corresponding to a selected overlay metrology recipe, where the selected pupil transmissivity distribution corresponds to a selected configuration of the one or more control zones providing transmission of a selected set of diffraction orders from the target to the detector.

Abstract: An overlay metrology system may include, an illumination sub-system, a collection sub-system and a controller. The illumination sub-system may include one or more illumination optics configured to direct an illumination beam to an overlay target on a sample as the sample is scanned along a stage-scan direction by a translation stage, where the overlay target includes one or more cells having a grating-over-grating structure with periodicity along the stage-scan direction. The collection sub-system may include an objective lens, a first photodetector located in a pupil plane at a location of overlap between 0-order diffraction and +1-order diffraction, and a second photodetector located in a pupil plane at a location of overlap between 0-order diffraction and ?1-order diffraction. The controller may receive time-varying interference signals from the first and second photodetectors and determine an overlay error between the first and second layers of the sample along the stage-scan direction.

Abstract: A metrology measurement apparatus may include one or more illumination sources, a beamsplitter configured to receive illumination from the one or more illumination sources from an illumination pathway and direct the illumination along a measurement pathway, and an objective lens. The objective lens may direct the illumination from the measurement pathway to a sample, collect light from the sample, and direct the collected light along the measurement pathway to the beamsplitter such that the beamsplitter may direct the collected light along a collection pathway to a detector. The apparatus may further include a pupil-plane scanner along the measurement pathway with a pupil relay and a deflector in a relayed pupil plane such that adjusting the deflector adjusts a position of the illumination spot on the sample without modifying a position of the illumination pupil distribution or a position of a distribution of the collected light along the collection pathway.

Abstract: An overlay metrology system may include, an illumination sub-system, a collection sub-system and a controller. The illumination sub-system may include one or more illumination optics configured to direct an illumination beam to an overlay target on a sample as the sample is scanned along a stage-scan direction by a translation stage, where the overlay target includes one or more cells having a grating-over-grating structure with periodicity along the stage-scan direction. The collection sub-system may include an objective lens, a first photodetector located in a pupil plane at a location of overlap between 0-order diffraction and +1-order diffraction, and a second photodetector located in a pupil plane at a location of overlap between 0-order diffraction and ?1-order diffraction. The controller may receive time-varying interference signals from the first and second photodetectors and determine an overlay error between the first and second layers of the sample along the stage-scan direction.

Abstract: A metrology system may include an imaging sub-system to image a metrology target buried in a sample, where the sample is formed from bonded first and second substrates with a metrology target at the interface. The metrology system may further include an illumination sub-system with an illumination field stop and an illumination pupil, where the illumination field stop includes an aperture to provide that a projected size of the field-stop aperture on a measurement plane corresponding to the metrology target matches a field of view of the detector at the measurement plane, and where the illumination pupil includes a central obscuration to provide oblique illumination of the metrology target with angles greater than a cutoff angle selected to prevent illumination from the illumination source from reflecting off of the bottom surface of the sample and through the field of view of the detector at the measurement plane.

Abstract: A spectral filter includes a curved filtering element including a concave surface forming a portion of a sphere. The concave surface may be positioned to receive light diverging from an output face of an optical fiber located at a first location proximate to a center of the sphere corresponding to the concave surface. The concave surface may transmit a first portion of a spectrum of the light. The concave surface may further reflect and focus a second portion of the spectrum to a second location proximate to the center of the sphere. The spectral filter may further include a collector to direct the second portion of the spectrum away from the output face of the optical fiber.

Abstract: An overlay metrology tool may include an illumination source, illumination optics to illuminate an overlay target having periodic features with one or more illumination beams, collection optics to direct diffracted light from the periodic features of the overlay target to a detector, an adjustable pupil mask located at a pupil plane, and a controller. The adjustable pupil mask may include one or more individually-addressable control zones distributed across the one or more portions of the pupil plane to provide an adjustable pupil transmissivity distribution. The controller may direct the adjustable pupil mask to provide a selected pupil transmissivity distribution corresponding to a selected overlay metrology recipe, where the selected pupil transmissivity distribution corresponds to a selected configuration of the one or more control zones providing transmission of a selected set of diffraction orders from the target to the detector.

Abstract: An illumination source may include two or more input light sources, a collector, and any combination of a beam uniformizer, a speckle reducer, or any number of output fibers to provide a selected illumination etendue. The collector may include one or more lenses to combine illumination from the two or more input light sources into an illumination beam, where the illumination from the two or more input light sources occupy different portions of an input aperture of the collector. The beam uniformizer may include a first noncircular-core fiber to receive the illumination beam, a second noncircular-core fiber, and one or more coupling lenses to relay a far-field distribution of the illumination beam from the first noncircular-core fiber to an input face of the second noncircular-core fiber to provide output light with uniform near-field and far-field distributions.

Abstract: A metrology system may include a controller coupled to a scanning metrology tool that images a sample in motion along a scan direction. The controller may receive an image of a metrology target on the sample from the scanning metrology tool, where the metrology target comprises a first measurement group including cells distributed along a transverse direction orthogonal to the scan direction, and a second measurement group separated from the first measurement group along the scan direction including cells distributed along the transverse direction. The controller may further generate at least a first metrology measurement based on at least one of the cells in the first measurement group, and generate at least a second metrology measurement based on at least one of the cells in the second measurement group.

Abstract: A multipole illumination system may include an illumination source to generate a source beam, one or more acousto-optic deflectors to diffract the source beam along at least two directions; one or more collection lenses to collect at least some of the diffracted light from the one or more acousto-optic deflectors, and a controller to generate one or more drive signals for the one or more acousto-optic deflectors. For example, the one or more drive signals may cause the one or more acousto-optic deflectors to generate a symmetric distribution of two or more illumination beams formed from light diffracted from the one or more acousto-optic deflectors and collected by the one or more collection lenses, where a distribution of wavelength and intensity of the two or more illumination beams is symmetric in a plane formed by the first and second directions.

Abstract: A tunable filter may include an input focusing optic, an output focusing optic, a linearly-varying filter located at a back focal plane of the input focusing optic and a front focal plane of the output focusing optic, an input angular scanning component located at a front focal plane of the input focusing optic configured to receive an input beam, and an output angular scanning component located at a back focal plane of the output focusing optic. The input focusing optic may receive the input beam from the input angular scanning component and direct the input beam to the linearly-varying filter, where a position of the input beam on the linearly-varying filter is selectable based on an angle of the input angular scanning component. The output focusing optic may receive a filtered beam from the linearly-varying filter and direct the filtered beam to the output angular scanning component.

Abstract: A metrology system may include a controller coupled to a scanning metrology tool that images a sample in motion along a scan direction. The controller may receive an image of a metrology target on the sample from the scanning metrology tool, where the metrology target comprises a first measurement group including cells distributed along a transverse direction orthogonal to the scan direction, and a second measurement group separated from the first measurement group along the scan direction including cells distributed along the transverse direction. The controller may further generate at least a first metrology measurement based on at least one of the cells in the first measurement group, and generate at least a second metrology measurement based on at least one of the cells in the second measurement group.

Abstract: A beamsplitter includes a substrate formed from a material transparent to wavelengths of light at least above a selected cutoff wavelength and reflective structures distributed across a surface of the substrate. The reflective structures split incident light having wavelengths above the selected cutoff wavelength into a reflected beam formed from portions of the incident light reflected from the reflective structures and a transmitted beam formed from portions of the incident light transmitted through the substrate. A splitting ratio of a power of the reflected beam to a power of the transmitted beam is based on a ratio of surface area of the reflective surfaces to an area of the incident light on the substrate. Separation distances between neighboring reflective structures are smaller than the cutoff wavelength such that diffracted power of the incident light having wavelengths above the selected cutoff wavelength is maintained below a selected tolerance.

Abstract: A metrology system may include a metrology tool to selectively perform metrology measurements in a static mode in which one or more metrology targets on a sample are stationary during a measurement or a scanning mode in which one or more metrology targets are in motion during a measurement, and a controller communicatively coupled to the translation stage and at least one of the one or more detectors. The controller may receive locations of metrology targets on the sample to be inspected, designate the metrology targets for inspection with the static mode or the scanning mode, direct the metrology tool to perform metrology measurements on the metrology targets in the static mode or the scanning mode based on the designation, and generate metrology data for the sample based on the metrology measurements on the metrology targets.