Abstract: An overlay metrology system may include an objective lens, illumination optics to illuminate an overlay target including a first grating with a first pitch on a first sample layer and a second grating with a second pitch on a second sample layer, where the first and second sample layers are separated by a layer separation distance greater than a depth of field of the objective lens. The system may further include collection optics with a radially-varying defocus distribution to compensate for the layer separation distance such that the first and second gratings are simultaneously in focus on the detector.

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.

Abstract: A multi-column metrology tool may include two or more measurement columns distributed along a column direction, where the two or more measurement columns simultaneously probe two or more measurement regions on a sample including metrology targets. A measurement column may include an illumination sub-system to direct illumination to the sample, a collection sub-system including a collection lens to collect measurement signals from the sample and direct it to one or more detectors, and a column-positioning sub-system to adjust a position of the collection lens. A measurement region of a measurement column may be defined by a field of view of the collection lens and a range of the positioning system in the lateral plane. The tool may further include a sample-positioning sub-system to scan the sample along a scan path different than the column direction to position metrology targets within the measurement regions of the measurement columns for measurements.

Abstract: A multi-column metrology tool may include two or more measurement columns distributed along a column direction, where the two or more measurement columns simultaneously probe two or more measurement regions on a sample including metrology targets. A measurement column may include an illumination sub-system to direct illumination to the sample, a collection sub-system including a collection lens to collect measurement signals from the sample and direct it to one or more detectors, and a column-positioning sub-system to adjust a position of the collection lens. A measurement region of a measurement column may be defined by a field of view of the collection lens and a range of the positioning system in the lateral plane. The tool may further include a sample-positioning sub-system to scan the sample along a scan path different than the column direction to position metrology targets within the measurement regions of the measurement columns for measurements.

Abstract: A metrology system may include an imaging sub-system including one or more lenses and a detector to image a sample, where the sample includes metrology target elements on two or more sample layers. The metrology system may further include a controller to determine layer-specific imaging configurations of the imaging sub-system to image the metrology target elements on the two or more sample layers within a selected image quality tolerance, where each layer-specific imaging configuration includes a selected configuration of one or more components of the imaging sub-system. The controller may further receive, from the imaging sub-system, one or more images of the metrology target elements on the two or more sample layers generated using the layer-specific imaging configurations. The controller may further provide a metrology measurement based on the one or more images of the metrology target elements on the two or more sample layers.

Abstract: A method for metrology includes directing at least one illumination beam to illuminate a semiconductor wafer on which at least first and second patterned layers have been deposited in succession, including a first target feature in the first patterned layer and a second target feature in the second patterned layer, overlaid on the first target feature. A sequence of images of the first and second target features is captured while varying one or more imaging parameters over the sequence. The images in the sequence are processed in order to identify respective centers of symmetry of the first and second target features in the images and measure variations in the centers of symmetry as a function of the varying image parameters. The measured variations are applied in measuring an overlay error between the first and second patterned layers.

Abstract: An overlay metrology system may scan a sample including inverted Moiré structure pairs along a scan direction, include an illumination sub-system to illuminate first and second Moiré structures of one of an inverted Moiré structure pair with common mutually coherent illumination beam distributions, and include an objective lens to capture at least +/?1 diffraction orders from sample, where a first pupil plane includes overlapping distributions of the collected light with an interference pattern associated with relative wavefront tilt. The system may also include a diffractive element in the first pupil plane, where one diffraction order associated with the first Moiré structure and one diffraction order associated with the second Moiré structure overlap at a common overlap region in a field plane, and a collection field stop located in the field plane to pass light in the common overlap region and block remaining light and remove the relative wavefront tilt.

Abstract: A multi-column metrology tool may include two or more measurement columns distributed along a column direction, where the two or more measurement columns simultaneously probe two or more measurement regions on a sample including metrology targets. A measurement column may include an illumination sub-system to direct illumination to the sample, a collection sub-system including a collection lens to collect measurement signals from the sample and direct it to one or more detectors, and a column-positioning sub-system to adjust a position of the collection lens. A measurement region of a measurement column may be defined by a field of view of the collection lens and a range of the positioning system in the lateral plane. The tool may further include a sample-positioning sub-system to scan the sample along a scan path different than the column direction to position metrology targets within the measurement regions of the measurement columns for measurements.

Abstract: An optical metrology system may include an overlay metrology tool for characterizing an overlay target on a sample, where the overlay target includes first-direction periodic features in a first set of layers of the sample, and second-direction periodic features in a second set of layers of the sample. The overlay metrology tool may simultaneously illuminate the overlay target with first illumination beams and second illumination beams and may further generate images of the overlay target based on diffraction of the first illumination beams and the second illumination beams by the overlay target, where diffraction orders of the first illumination beams contribute to resolved image formation of only the first-direction periodic features, and where diffraction orders of the second illumination beams contribute to resolved image formation of only the second-direction periodic features. The system may further generate overlay measurements along the first and second measurement directions based on the images.

Abstract: An optical metrology system may include an overlay metrology tool for characterizing an overlay target on a sample, where the overlay target includes first-direction periodic features in a first set of layers of the sample, and second-direction periodic features in a second set of layers of the sample. The overlay metrology tool may simultaneously illuminate the overlay target with first illumination beams and second illumination beams and may further generate images of the overlay target based on diffraction of the first illumination beams and the second illumination beams by the overlay target, where diffraction orders of the first illumination beams contribute to resolved image formation of only the first-direction periodic features, and where diffraction orders of the second illumination beams contribute to resolved image formation of only the second-direction periodic features. The system may further generate overlay measurements along the first and second measurement directions based on the images.

Abstract: An overlay metrology system may include an illumination an illumination source to generate an illumination beam, one or more illumination optics to direct the illumination beam to an overlay target on a sample as the sample is scanned relative to the illumination beam along a scan direction, the target including one or more cells having Moiré structures. The system may also include two photodetectors at locations of a pupil plane associated with Moiré or overlapping diffraction orders from the Moiré structures. The system may then generate overlay measurements based on time-varying interference signals captured by the detector as the sample is scanned.

Abstract: An overlay metrology system may include illumination sources configured to generate one or more pairs of mutually coherent illumination beams and illumination optics to direct the pairs of illumination beams to an overlay target at common altitude incidence angles and symmetrically opposed azimuthal incidence angles, where the overlay target includes two or more grating structures distributed along one or more measurement directions. The system may further include imaging optics to image the overlay target onto detectors when implementing the metrology recipe, where an image of a particular one of the two or more grating structures is generated exclusively with a single non-zero diffraction order of light from each of the illumination beams within the particular one of the pairs of illumination beams. The system may further include a controller to determine overlay measurements based on images of the overlay target.

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 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: An overlay metrology system may scan a sample including inverted Moire structure pairs along a scan direction, include an illumination sub-system to illuminate first and second Moire structures of one of an inverted Moire structure pair with common mutually coherent illumination beam distributions, and include an objective lens to capture at least +/-1 diffraction orders from sample, where a first pupil plane includes overlapping distributions of the collected light with an interference pattern associated with relative wavefront tilt. The system may also include a diffractive element in the first pupil plane, where one diffraction order associated with the first Moire structure and one diffraction order associated with the second Moiré structure overlap at a common overlap region in a field plane, and a collection field stop located in the field plane to pass light in the common overlap region and block remaining light and remove the relative wavefront tilt.

Abstract: An overlay metrology tool may include an illumination source to generate a first illumination beam distribution with a first linear polarization and a second illumination beam distribution with a second linear polarization orthogonal to the first linear polarization, an illumination sub-system to sequentially illuminate two or more cell pairs of an overlay target on a sample having orthogonally oriented grating-over-grating structures, a collection sub-system with two collection channels to capture collected light from an illuminated cell pair and filtering optics to direct light from different cells in an illuminated cell pair to different collection channels for detection. The tool may further include a controller to generate separate overlay measurements for orthogonally-oriented grating-over-grating structures in the two or more cell pairs.

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: 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: An overlay metrology system may include an overlay metrology tool suitable for measurement of an overlay target on a sample, the overlay target including one or more grating structures with patterned features distributed along one or more measurement directions. The overlay metrology tool may include an objective lens and an illumination pathway to illuminate the overlay target with two or more oblique illumination lobes distributed among one or more illumination distributions such that, for each of the measurement directions, diffraction orders of the one or more illumination distributions by the overlay target that are collected by the objective lens exclusively include a 0-order diffraction lobe and a single first-order diffraction lobe from at least one of the two or more illumination lobes. The overlay metrology tool may further include at least one detector to image the sample and a controller to generate overlay measurements based on the images.

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.