Abstract: An overlay metrology system and method are disclosed for generating an overlay measurement of an overlay target including cells with structures in reversed orders. The overlay metrology system may include an illumination sub-system and a collection sub-system. The collection sub-system may include one or more detectors to collect measurement light from a sample. The sample, according to a metrology recipe, may include an overlay target having a first cell of a first cell type and a second cell of a second cell type, where the second cell type includes structures in a reverse order relative to the first cell type. The metrology recipe may include receiving detection signals, generating an overlay measurement of each cell based on the detection signals, and generating an overlay measurement associated with the overlay target based on a value indicative of an average of the overlay measurements of each cell.

Abstract: A metrology system and method for imaging samples such as semiconductor devices having metrology targets for measuring overlay. In embodiments, the system includes an illumination source configured to generate a multiwavelength illumination beam, collection channels for collecting wavelength-selective collected light from the sample in accordance with a metrology recipe, and a controller configured to receive wavelength-selective datasets and determine at least one overlay measurement from the wavelength-selective datasets received.

Abstract: An overlay metrology system includes a controller communicatively coupled to a first photodetector and a second photodetector. The controller may be configured to receive one or more signals from the first and second photodetector as an overlay target is scanned. The overlay target may include a plurality of measurement cells, where each measurement cell includes a grating-over-grating structure including a first-layer grating feature on a first layer of a sample and a second-layer grating feature on a second layer of the sample in an overlapping region. The first-layer grating feature and the second-layer grating feature may have a common pitch. The controller may be further configured to determine one or more differential signals between the first photodetector and the second photodetector for each measurement cell of the plurality of measurement cells and determine an overlay measurement based on the determined one or more differential signals.

Abstract: A method for overlay metrology may include generating broadband illumination beams and directing the broadband illumination beams to an overlay target on a sample, where the overlay target may include cells having periodic features formed as overlapping grating structures. The method may include generating diffracted light using the periodic features of the overlay target, where the periodic features may act as a diffraction grating to generate diffracted light by separating the broadband illumination beam into a plurality of wavelengths. The method may include generating pupil images of cells of the overlay target, where a distribution of light in the pupil plane may include first-order diffraction lobes, where spectra of the first-order diffraction lobes may be spatially dispersed in the pupil plane. The method may include generating an overlay measurement based on portions of the pupil images corresponding to selected wavelengths of the spectra of the first-order diffraction lobes.

Abstract: A system includes an illumination source configured to generate an illumination beam, and a collection sub-system that includes an objective lens, one or more detectors located at a collection pupil plane, a light modulator, and a controller. The light modulator is configured to direct one or more selected portions of measurement light to the one or more detectors. The controller includes one or more processors configured to execute program instructions causing the one or more processors to execute a metrology recipe by: receiving detection signals from the one or more detectors, wherein the detection signals are associated with the one or more selected portions of the measurement light directed to the one or more detectors; and generating an overlay measurement associated with at least two layers of a sample based on the detection signals.

Abstract: A method may include illuminating an overlay target on a sample as the sample is translated along a stage-scan direction with two or more illumination beams. The two or more illumination beams include at least a first illumination beam having a first wavelength and a second illumination beam having a second wavelength, where the first wavelength is different than the second wavelength. The method may further include receiving time-varying interference signals from two or more photodetectors associated with a first-layer grating feature and a second-layer grating feature of a grating-over-grating structure. The first-layer grating feature may have a first pitch and the second-layer grating feature may have a second pitch different than the first pitch. The method may further include determining an overlay measurement between one of the first-layer grating feature and the second-layer grating feature of the sample based on the time-varying interference signals.

Abstract: A system and method for adjusting a focus based on a scan are disclosed. The system may include an optical sub-system configured to detect light from a light modulation target of a sample as the sample is scanned along a scan direction. Two or more detection elements may be configured to detect the light modulation target at different points in time as the sample is scanned along the scan direction by virtue of a spatial separation between the two or more detection elements. The system may determine a time difference between different points in time that the light modulation target is detected during the scanning of the sample, determine a defocused value indicative of being under-focused or over-focused based on the time difference, and direct an adjustment of a focus of the optical sub-system based on the defocused value.

Abstract: A method includes illuminating an overlay target with a plurality of measurement cells. The method further includes receiving time-varying interference signals from a first and second photodetector as an overlay target is scanned along a stage-scan direction by a translation stage when implementing a metrology recipe. The overlay target may include a plurality of measurement cells, where each measurement cell includes a grating-over-grating structures including a first-layer grating feature on a first layer of the sample and a second-layer grating feature on a second layer of the sample in an overlapping region. The first-layer grating feature and the second-layer grating feature may have a similar pitch. The method includes determining one or more differential signals between the first photodetector and the second photodetector for each measurement cell of the plurality of measurement cells. The method includes determining an overlay measurement based on the determined one or more differential signals.

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 is disclosed. The overlay metrology system may include a controller with one or more processors. The processors may be configured to execute program instructions causing the processors to receive pupil images of collected light from an overlay target and receive a known phase distribution to be introduced to an illumination beam directed at the overlay target. The processors may model an intensity function relating the pupil images, the known phase distribution, and one or more decentered shift parameters of structures of the overlay target. The processors may fit the pupil images to the intensity function depending on the known phase distribution and the decentered shift parameters. The processors may generate an overlay measurement based on the fit.

Abstract: An overlay metrology system is disclosed. The overlay metrology system may include a controller with one or more processors. The processors may be configured to execute program instructions causing the processors to receive pupil images of collected light from an overlay target and receive a known phase distribution to be introduced to an illumination beam directed at the overlay target. The processors may model an intensity function relating the pupil images, the known phase distribution, and one or more decentered shift parameters of structures of the overlay target. The processors may fit the pupil images to the intensity function depending on the known phase distribution and the decentered shift parameters. The processors may generate an overlay measurement based on the fit.

Abstract: A method for overlay metrology may include generating broadband illumination beams and directing the broadband illumination beams to an overlay target on a sample, where the overlay target may include cells having periodic features formed as overlapping grating structures. The method may include generating diffracted light using the periodic features of the overlay target, where the periodic features may act as a diffraction grating to generate diffracted light by separating the broadband illumination beam into a plurality of wavelengths. The method may include generating pupil images of cells of the overlay target, where a distribution of light in the pupil plane may include first-order diffraction lobes, where spectra of the first-order diffraction lobes may be spatially dispersed in the pupil plane. The method may include generating an overlay measurement based on portions of the pupil images corresponding to selected wavelengths of the spectra of the first-order diffraction lobes.

Abstract: A method may include receiving time-varying interference signals from two or more photodetectors associated with a grating structure and a reference grating structure. The grating structure may include one or more diffraction gratings, where the reference grating structure includes a reference grating arranged next to the one or more diffraction gratings of the grating structure and where the one or more illumination beams simultaneously interact with grating structure and the reference grating structure as the sample is scanned relative to the illumination beam. The method may include determining at least one of a real-time position or a scanning velocity of the grating structure during the scan based on the reference grating signal. The method may include determining one or more overlay errors based on the grating signals from the grating structure and the real-time position of the grating structure during the scan determined based on the reference grating signal.

Abstract: A method may include receiving time-varying interference signals from two or more photodetectors associated with a first exposure structure and a second exposure structure in one or more cells as an overlay target is scanned in accordance with a metrology recipe, where the first exposure structure and the second exposure structure form a side-by-side grating, where the side-by-side grating includes one or more diffraction gratings, where at least one diffraction grating is a non-overlapping side-by-side grating, where the first exposure structure is arranged adjacent to the second exposure structure, where the side-by-side grating is periodic along the scan direction.

Abstract: A method for semiconductor metrology includes depositing first and second overlying film layers on a semiconductor substrate and patterning the layers to define an overlay target. The target includes a first grating pattern in the first layer, including at least a first linear grating oriented in a first direction and at least a second linear grating oriented in a second direction perpendicular to the first direction, and a second grating pattern in the second layer, including at least a third linear grating identical to the first linear grating and a fourth linear grating identical to the second linear grating. The second grating pattern has a nominal offset relative to the first grating pattern by first and second displacements in the first and second directions, respectively. A scatterometric image of the substrate is captured and processed to estimate an overlay error between the patterning of the first and second layers.

Abstract: Metrology is performed on a semiconductor wafer using a system with an apodizer. A spot is formed on the semiconductor wafer with a diameter from 2 nm to 5 nm. The associated beam of light has a wavelength from 400 nm to 800 nm. Small target measurement can be performed at a range of optical wavelengths.

Abstract: An overlay metrology target includes a multi-layer grating structure formed as an overlapping grating structure with different pitches on three or more layers of a sample. The three or more layers of the sample may include at least a first layer, a second layer, and a third layer, where the overlapping grating structure is periodic along at least one of the scan direction or a direction orthogonal to the scan direction. The multi-layer grating structure may include a first-layer grating on the first layer with a first pitch, a second-layer grating on the second layer with a second pitch, and a third-layer grating on the third layer with a third pitch.

Abstract: An overlay metrology system and method are disclosed for generating an overlay measurement of an overlay target including cells with structures in reversed orders. The overlay metrology system may include an illumination sub-system and a collection sub-system. The collection sub-system may include one or more detectors to collect measurement light from a sample. The sample, according to a metrology recipe, may include an overlay target having a first cell of a first cell type and a second cell of a second cell type, where the second cell type includes structures in a reverse order relative to the first cell type. The metrology recipe may include receiving detection signals, generating an overlay measurement of each cell based on the detection signals, and generating an overlay measurement associated with the overlay target based on a value indicative of an average of the overlay measurements of each cell.

Abstract: A method for semiconductor metrology includes depositing first and second overlying film layers on a semiconductor substrate and patterning the layers to define an overlay target. The target includes a first grating pattern in the first layer, including at least a first linear grating oriented in a first direction and at least a second linear grating oriented in a second direction perpendicular to the first direction, and a second grating pattern in the second layer, including at least a third linear grating identical to the first linear grating and a fourth linear grating identical to the second linear grating. The second grating pattern has a nominal offset relative to the first grating pattern by first and second displacements in the first and second directions, respectively. A scatterometric image of the substrate is captured and processed to estimate an overlay error between the patterning of the first and second layers.

Abstract: An overlay metrology system with pitches in multiple directions in a single cell is disclosed. The overlay target may, according to a metrology recipe, include a multi-layer structure on two or more layers of a cell of the sample. The multi-layer structure may include structures in each layer having one or more pitches in one or more directions of periodicity. The multi-layer structure may include structures with a first pitch in a first direction, a second pitch in a second direction, a third pitch in the first direction, and a fourth pitch in the second direction. At least one of the first pitch or the third pitch may be different than at least one of the second pitch or the fourth pitch.