Abstract: Metrology target design methods and verification targets are provided. Methods comprise using OCD data related to designed metrology target(s) as an estimation of a discrepancy between a target model and a corresponding actual target on a wafer, and adjusting a metrology target design model to compensate for the estimated discrepancy. The dedicated verification targets may comprise overlay target features and be size optimized to be measureable by an OCD sensor, to enable compensation for inaccuracies resulting from production process variation. Methods also comprise modifications to workflows between manufacturers and metrology vendors which provide enable higher fidelity metrology target design models and ultimately higher accuracy of metrology measurements.

Abstract: A target for use in the optical measurement of misregistration in the manufacture of semiconductor devices, the target including a first periodic structure formed on a first layer of a semiconductor device and having a first pitch along an axis and a second periodic structure formed on a second layer of the semiconductor device and having a second pitch along the axis, different from the first pitch, the second periodic structure extending beyond the first periodic structure along the axis.

Abstract: Systems and method are provided for analyzing target, process and metrology configuration sensitivities to a wide range of parameters, according to external requirements or inner development and verification needs. Systems comprise the following elements. An input module is arranged to receive parameters relating to targets, target metrology conditions and production processes, to generate target data. A metrology simulation unit is arranged to simulate metrology measurements of targets from the target data and to generate multiple metrics that quantify the simulated target measurements. A sensitivity analysis module is arranged to derive functional dependencies of the metrics on the parameters and to define required uncertainties of the parameters with respect to the derived functional dependencies. Finally, a target optimization module is arranged to rank targets and target metrology conditions with respect to the simulated target measurements.

Abstract: Metrology target design methods and verification targets are provided. Methods include using OCD data related to designed metrology target(s) as an estimation of a discrepancy between a target model and a corresponding actual target on a wafer, and adjusting a metrology target design model to compensate for the estimated discrepancy. The dedicated verification targets may include overlay target features and be size optimized to be measurable by an OCD sensor, to enable compensation for inaccuracies resulting from production process variation. Methods also include modifications to workflows between manufacturers and metrology vendors which provide enabled higher fidelity metrology target design models and ultimately higher accuracy of metrology measurements.

Abstract: A metrology system may include a controller coupled to a metrology tool. The controller may receive a metrology target design including at least a first feature formed by exposing a first exposure field on a sample with a lithography tool, and at least a second feature formed by exposing a second exposure field on the sample with the lithography tool, where the second exposure field overlaps the first exposure field at a location of a metrology target on the sample. The controller may further receive metrology data associated with the metrology target fabricated according to the metrology target design, determine one or more fabrication errors during fabrication of the metrology target based on the metrology data, and generate correctables to adjust one or more fabrication parameters of the lithography tool in one or more subsequent lithography steps based on the one or more fabrication errors.

Abstract: Metrology targets, design methods and measurement methods thereof are provided with periodic structure(s) which are oblique with respect to orthogonal production axes X and Y of the lithography tool—enabling more accurate overlay measurements of devices having diagonal (oblique, tilted) elements such as DRAM devices. One or more oblique periodic structure(s) may be used to provide one- or two-dimensional signals, with respect to one or more layers, possibly providing overlay measurements for multiple steps applied to one layer. The oblique periodic structure(s) may be used to modify current metrology target designs (e.g., imaging targets and/or scatterometry targets) or to design new targets, and measurement algorithms may be adjusted respectively to derive signals from the oblique periodic structure(s) and/or to provide pre-processed images thereof. The disclosed targets are process compatible and reflect more accurately the device overlays with respect to various process steps.

Abstract: Systems and methods are provided, which calculate overlay misregistration error estimations from analyzed measurements of each ROI (region of interest) in at least one metrology imaging target, and incorporate the calculated overlay misregistration error estimations in a corresponding estimation of overlay misregistration. Disclosed embodiments provide a graduated and weighted analysis of target quality which may be integrated in a continuous manner into the metrology measurement processes, and moreover evaluates target quality in terms of overlay misregistration, which forms a common basis for evaluation of errors from different sources, such as characteristics of production steps, measurement parameters and target characteristics.

Abstract: Imaging metrology targets and methods are provided, which combine one-dimensional (1D) elements designed to provide 1D imaging metrology signals along at least two measurement directions and two-dimensional (2D) elements designed to provide at least one 2D imaging metrology overlay signal. The target area of the 1D elements may enclose the 2D elements or the target areas of the 1D and 2D elements may be partially or fully congruent. The compound targets are small, possibly multilayered, and may be designed to be process compatible (e.g., by segmentation of the elements, interspaces between elements and element backgrounds) and possibly be produced in die. Two dimensional elements may be designed to be periodic to provide additional one dimensional metrology signals.

Abstract: Metrology methods and targets are provided for reducing or eliminating a difference between a device pattern position and a target pattern position while maintaining target printability, process compatibility and optical contrast—in both imaging and scatterometry metrology. Pattern placement discrepancies may be reduced by using sub-resolved assist features in the mask design which have a same periodicity (fine pitch) as the periodic structure and/or by calibrating the measurement results using PPE (pattern placement error) correction factors derived by applying learning procedures to specific calibration terms, in measurements and/or simulations. Metrology targets are disclosed with multiple periodic structures at the same layer (in addition to regular target structures), e.g., in one or two layers, which are used to calibrate and remove PPE, especially when related to asymmetric effects such as scanner aberrations, off-axis illumination and other error sources.

Abstract: Systems and methods are provided, which calculate overlay misregistration error estimations from analyzed measurements of each ROI (region of interest) in at least one metrology imaging target, and incorporate the calculated overlay misregistration error estimations in a corresponding estimation of overlay misregistration. Disclosed embodiments provide a graduated and weighted analysis of target quality which may be integrated in a continuous manner into the metrology measurement processes, and moreover evaluates target quality in terms of overlay misregistration, which forms a common basis for evaluation of errors from different sources, such as characteristics of production steps, measurement parameters and target characteristics.

Abstract: Methods and systems are provided, which identify specified metrology target abnormalities using selected metrics and classify the identified target abnormalities geometrically to link them to corresponding sources of error. Identification may be carried out by deriving target signals such as kernels from specified regions of interest (ROIs) from corresponding targets on a wafer, calculating the metrics from the target signals using respective functions and analyzing the metrics to characterize the targets.

Abstract: A system for providing illumination to a measurement head for optical metrology is configured to combine illumination beams from a plurality of illumination sources to deliver illumination at one or more selected wavelengths to the measurement head. The intensity and/or spatial coherence of illumination delivered to the measurement head is controlled. Illumination at one or more selected wavelengths is delivered from a broadband illumination source configured for providing illumination at a continuous range of wavelengths.

Abstract: Method, metrology modules and RCA tool are provided, which use the behavior of resonance region(s) in measurement landscapes to evaluate and characterize process variation with respect to symmetric and asymmetric factors, and provide root cause analysis of the process variation with respect to process steps. Simulations of modeled stacks with different layer thicknesses and process variation factors may be used to enhance the analysis and provide improved target designs, improved algorithms and correctables for metrology measurements. Specific targets that exhibit sensitive resonance regions may be utilize to enhance the evaluation of process variation.

Abstract: Method, metrology modules and RCA tool are provided, which use the behavior of resonance region(s) in measurement landscapes to evaluate and characterize process variation with respect to symmetric and asymmetric factors, and provide root cause analysis of the process variation with respect to process steps. Simulations of modeled stacks with different layer thicknesses and process variation factors may be used to enhance the analysis and provide improved target designs, improved algorithms and correctables for metrology measurements. Specific targets that exhibit sensitive resonance regions may be utilize to enhance the evaluation of process variation.

Abstract: Methods and systems for minimizing of algorithmic inaccuracy in scatterometry overlay (SCOL) metrology are provided. SCOL targets are designed to limit the number of oscillation frequencies in a functional dependency of a resulting SCOL signal on the offset and to reduce the effect of higher mode oscillation frequencies. The targets are segmented in a way that prevents constructive interference of high modes with significant amplitudes, and thus avoids the inaccuracy introduced by such terms into the SCOL signal. Computational methods remove residual errors in a semi-empirical iterative process of compensating for the residual errors algorithmically or through changes in target design.

Abstract: Disclosed is a method for determining an overlay error between at least two layers in a multiple layer sample. An imaging optical system is used to measure multiple measured optical signals from multiple periodic targets on the sample, and the targets each have a first structure in a first layer and a second structure in a second layer. There are predefined offsets between the first and second structures A scatterometry overlay technique is used to analyze the measured optical signals of the periodic targets and the predefined offsets of the first and second structures of the periodic targets to thereby determine an overlay error between the first and second structures of the periodic targets. The scatterometry overlay technique is a phase based technique, and the imaging optical system is configured to have an illumination and/or collection numerical aperture (NA) and/or spectral band selected so that a specific diffraction order is collected and measured for the plurality of measured optical signals.

Abstract: The disclosure is directed to various apodization schemes for pupil imaging scatterometry. In some embodiments, the system includes an apodizer disposed within a pupil plane of the illumination path. In some embodiments, the system further includes an illumination scanner configured to scan a surface of the sample with at least a portion of apodized illumination. In some embodiments, the system includes an apodized pupil configured to provide a quadrupole illumination function. In some embodiments, the system further includes an apodized collection field stop. The various embodiments described herein may be combined to achieve certain advantages.

Abstract: A metrology system for determining overlay is disclosed. The system includes an optical assembly for capturing images of an overlay mark and a computer for analyzing the captured images to determine whether there is an overlay error. The mark comprises first and second regions that each include at least two separately generated working zones, juxtaposed relative to one another, configured to provide overlay information in a first direction, and include a periodic structure having coarsely segmented elements. The mark comprises third and fourth regions that each include at least two separately generated working zones, juxtaposed relative to one another, configured to provide overlay information in a second direction, and include a periodic structure having coarsely segmented elements.

Abstract: A system for providing illumination to a measurement head for optical metrology is configured to combine illumination beams from a plurality of illumination sources to deliver illumination at one or more selected wavelengths to the measurement head. The intensity and/or spatial coherence of illumination delivered to the measurement head is controlled. Illumination at one or more selected wavelengths is delivered from a broadband illumination source configured for providing illumination at a continuous range of wavelengths.

Abstract: Metrology target design methods and verification targets are provided. Methods include using OCD data related to designed metrology target(s) as an estimation of a discrepancy between a target model and a corresponding actual target on a wafer, and adjusting a metrology target design model to compensate for the estimated discrepancy. The dedicated verification targets may include overlay target features and be size optimized to be measureable by an OCD sensor, to enable compensation for inaccuracies resulting from production process variation. Methods also include modifications to workflows between manufacturers and metrology vendors which provide enable higher fidelity metrology target design models and ultimately higher accuracy of metrology measurements.