Methods and systems for characterizing dimensions and material properties of semiconductor devices by transmission small angle x-ray scatterometry (TSAXS) systems having relatively small tool footprint are described herein. The methods and systems described herein enable Q space resolution adequate for metrology of semiconductor structures with reduced optical path length. In general, the x-ray beam is focused closer to the wafer surface for relatively small targets and closer to the detector for relatively large targets. In some embodiments, a high resolution detector with small point spread function (PSF) is employed to mitigate detector PSF limits on achievable Q resolution. In some embodiments, the detector locates an incident photon with sub-pixel accuracy by determining the centroid of a cloud of electrons stimulated by the photon conversion event. In some embodiments, the detector resolves one or more x-ray photon energies in addition to location of incidence.

A method of aligning a wafer for semiconductor fabrication processes may include applying a magnetic field to a wafer, detecting one or more residual magnetic fields from one or more alignment markers within the wafer, responsive to the detected one or more residual magnetic fields, determining locations of the one or more alignment markers. The marker locations may be determined relative to an ideal grid, followed by determining a geometrical transformation model for aligning the wafer, and aligning the wafer responsive to the geometrical transformation model. Related methods and systems are also disclosed.

An overlay mark includes a first, a second, a third, and a fourth component. The first component is located in a first region of the first overlay mark and includes a plurality of gratings that extend in a first direction. The second component is located in a second region of the first overlay mark and includes a plurality of gratings that extend in the first direction. The third component is located in a third region of the first overlay mark and includes a plurality of gratings that extend in a second direction different from the first direction. The fourth component is located in a fourth region of the first overlay mark and includes a plurality of gratings that extend in the second direction. The first region is aligned with the second region. The third region is aligned with the fourth region.

Disclosed is a method for determining a stage position or correction therefor in a lithographic process. The method comprises obtaining transmission data describing the transmission of alignment radiation onto the substrate; obtaining position data relating to a stage position of said stage and/or a sensor position of said sensor. A weighting is determined for the position data based on said transmission data. The position based on said transmission data, position data and weighting.

An image analysis method for identifying features in an image of a part of an array of features formed by a multi-step process, the method comprising: analyzing variations in features visible in the image; and associating features of the image with steps of the multi-step process based at least in part on results of the analyzing.

The present disclosure provides a system. The system includes a metrology tool configured to collect overlay errors from a patterned substrate; and a controller module coupled to the metrology tool and configured to generate an overlay compensation from the collected overlay errors, wherein the generating of the overlay compensation includes identifying a portion of the overlay errors as a set of outliers, identifying inside the set of outliers overlay errors not due to reticle effects, thereby creating a set of noise, excluding the set of noise from overlay errors, thereby creating a set of filtered overlay errors, and calculating the overlay compensation based on the set of filtered overlay errors.

A method for determining a metric of a feature on a substrate obtained by a semiconductor manufacturing process involving a lithographic process, the method including: obtaining an image of at least part of the substrate, wherein the image includes at least the feature; determining a contour of the feature from the image; determining a plurality of segments of the contour; determining respective weights for each of the plurality of segments; determining, for each of the segments, an image-related metric; and determining the metric of the feature in dependence on the weights and the calculated image-related metric of each of the segments.

A method of applying a measurement correction includes determining an orthogonal subspace used to characterize a first principal component of the measurement and a second principal component of the measurement, and rotating the orthogonal subspace by a first angle such that the first principle component rotates to become a first factor vector and the second principle component rotates to become a second factor vector. An asymmetry vector is generated by rotating the second factor vector by a second angle, where the asymmetry vector and the first factor vector define a non-orthogonal subspace. An asymmetry contribution is determined in the measurement based on the projection of the measurement onto the first factor vector in the non-orthogonal subspace. The method also includes subtracting the asymmetry contribution from the measurement.

Methods and systems for measuring the orientation of a wafer at or near an X-ray scatterometry measurement location are described herein. In one aspect, an X-ray scatterometry based metrology system includes a wafer orientation measurement system that measures wafer orientation based on a single measurement without intervening stage moves. In some embodiments, an orientation measurement spot is coincident with an X-ray measurement spot. In some embodiments, an X-ray scatterometry measurement and a wafer orientation measurement are performed simultaneously. In another aspect, signals detected by a wafer orientation measurement system are filtered temporally, spatially, or both, to improve tracking. In another aspect, a wafer orientation measurement system is calibrated to identify the orientation of the wafer with respect to an incident X-ray beam. In another aspect, a wafer under measurement is positioned based on the measured orientation in a closed loop or open loop manner.

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.