Abstract: Methods and systems for estimating values of parameters of interest from X-ray scatterometry measurements with reduced computational effort are described herein. Values of parameters of interest are estimated by regression using a trained, machine learning (ML) based electromagnetic (EM) response model. A training data set includes sets of Design Of Experiments (DOE) values of parameters of interest and corresponding DOE values of a plurality of electromagnetic response metrics. In some examples, values of parameters of interest are determined from measured images based on regression using a sequence of trained ML based electromagnetic response models. In some examples, input values employed to train the ML based EM response model are scaled based on model output variation.

Abstract: Methods and systems for characterizing dimensions and material properties of semiconductor devices by full beam x-ray scatterometry are described herein. A full beam x-ray scatterometry measurement involves illuminating a sample with an X-ray beam and detecting the intensities of the resulting zero diffraction order and higher diffraction orders simultaneously for one or more angles of incidence relative to the sample. The simultaneous measurement of the direct beam and the scattered orders enables high throughput measurements with improved accuracy. The full beam x-ray scatterometry system includes one or more photon counting detectors with high dynamic range and thick, highly absorptive crystal substrates that absorb the direct beam with minimal parasitic backscattering.

Abstract: Methods and systems for estimating values of geometric parameters characterizing in-plane, distorted shapes of high aspect ratio semiconductor structures based on x-ray scatterometry measurements are presented herein. A parameterized geometric model captures the scattering signature of in-plane, non-elliptical distortions in hole shape. By increasing the number of independent parameters employed to describe the in-plane shape of hole structures the model fit to the actual shape of high aspect ratio structures is improved. In one aspect, a geometrically parameterized measurement model includes more than two degrees of freedom to characterize the in-plane shape of a measured structure. In some embodiments, the geometric model includes a closed curve having three degrees of freedom or more. In some embodiments, the geometric model includes a piecewise assembly of two or more conic sections.

Abstract: Methods and systems for characterizing dimensions and material properties of semiconductor devices by full beam x-ray scatterometry are described herein. A full beam x-ray scatterometry measurement involves illuminating a sample with an X-ray beam and detecting the intensities of the resulting zero diffraction order and higher diffraction orders simultaneously for one or more angles of incidence relative to the sample. The simultaneous measurement of the direct beam and the scattered orders enables high throughput measurements with improved accuracy. The full beam x-ray scatterometry system includes one or more photon counting detectors with high dynamic range and thick, highly absorptive crystal substrates that absorb the direct beam with minimal parasitic backscattering.

Abstract: Methods and systems for characterizing dimensions and material properties of semiconductor devices by full beam x-ray scatterometry are described herein. A full beam x-ray scatterometry measurement involves illuminating a sample with an X-ray beam and detecting the intensities of the resulting zero diffraction order and higher diffraction orders simultaneously for one or more angles of incidence relative to the sample. The simultaneous measurement of the direct beam and the scattered orders enables high throughput measurements with improved accuracy. The full beam x-ray scatterometry system includes one or more photon counting detectors with high dynamic range and thick, highly absorptive crystal substrates that absorb the direct beam with minimal parasitic backscattering.

Abstract: Methods and systems for characterizing dimensions and material properties of semiconductor devices by full beam x-ray scatterometry are described herein. A full beam x-ray scatterometry measurement involves illuminating a sample with an X-ray beam and detecting the intensities of the resulting zero diffraction order and higher diffraction orders simultaneously for one or more angles of incidence relative to the sample. The simultaneous measurement of the direct beam and the scattered orders enables high throughput measurements with improved accuracy. The full beam x-ray scatterometry system includes one or more photon counting detectors with high dynamic range and thick, highly absorptive crystal substrates that absorb the direct beam with minimal parasitic backscattering.

Abstract: A system, method and computer program product are provided for selecting signals to be measured utilizing a metrology tool that optimizes the precision of the measurement. The technique includes the steps of simulating a set of signals for measuring one or more parameters of a metrology target. A normalized Jacobian matrix corresponding to the set of signals is generated, a subset of signals in the simulated set of signals is selected that optimizes a performance metric associated with measuring the one or more parameters of the metrology target based on the normalized Jacobian matrix, and a metrology tool is utilized to collect a measurement for each signal in the subset of signals for the metrology target. For a given number of signals collected by the metrology tool, this technique optimizes the precision of such measurements over conventional techniques that collect signals uniformly distributed over a range of process parameters.

Abstract: Optimization of optical parametric models for structural analysis using optical critical dimension metrology is described. A method includes determining a first optical model fit for a parameter of a structure. The first optical model fit is based on a domain of quantities for a first model of the structure. A first near optical field response is determined for a first quantity of the domain of quantities and a second near optical field response is determined for a second, different quantity of the domain of quantities. The first and second near optical field responses are compared to locate a common region of high optical field intensity for the parameter of the structure. The first model of the structure is modified to provide a second, different model of the structure. A second, different optical model fit is determined for the parameter of the structure based on the second model of the structure.

Abstract: Methods and systems for optimizing measurement system parameter settings of an x-ray based metrology system are presented. X-ray based metrology systems employing an optimized set of measurement system parameters are used to measure structural, material, and process characteristics associated with different semiconductor fabrication processes with greater precision and accuracy. In one aspect, a set of values of one or more machine parameters that specify a measurement scenario is refined based at least in part on a sensitivity of measurement data to a previous set of values of the one or more machine parameters. The refinement of the values of the machine parameters is performed to maximize precision, maximize accuracy, minimize correlation between parameters of interest, or any combination thereof. Refinement of the machine parameter values that specify a measurement scenario can be used to optimize the measurement recipe to reduce measurement time and increase measurement precision and accuracy.

Abstract: Disclosed are apparatus and methods for determining a structure or process parameter value of a target of interest on a semiconductor wafer. A plurality of collection patterns are defined for a spatial light beam controller positioned at a pupil image plane of a metrology tool. For each collection pattern, a signal is collected from a sensor of the metrology tool, and each collected signal represents a combination of a plurality of signals that the spatial light beam controller samples, using each collection pattern, from a pupil image of the target of interest. The collection patterns are selected so that the pupil image is reconstructable based on the collection patterns and their corresponding collection signals. The collected signal for each of the collection patterns is analyzed to determine a structure or process parameter value for the target of interest.

Abstract: Methods and systems for characterizing dimensions and material properties of semiconductor devices by full beam x-ray scatterometry are described herein. A full beam x-ray scatterometry measurement involves illuminating a sample with an X-ray beam and detecting the intensities of the resulting zero diffraction order and higher diffraction orders simultaneously for one or more angles of incidence relative to the sample. The simultaneous measurement of the direct beam and the scattered orders enables high throughput measurements with improved accuracy. The full beam x-ray scatterometry system includes one or more photon counting detectors with high dynamic range and thick, highly absorptive crystal substrates that absorb the direct beam with minimal parasitic backscattering.

Abstract: Disclosed are apparatus and methods for performing small angle x-ray scattering metrology. This system includes an x-ray source for generating x-rays and illumination optics for collecting and reflecting or refracting a portion of the generated x-rays towards a particular focus point on a semiconductor sample in the form of a plurality of incident beams at a plurality of different angles of incidence (AOIs). The system further includes a sensor for collecting output x-ray beams that are scattered from the sample in response to the incident beams on the sample at the different AOIs and a controller configured for controlling operation of the x-ray source and illumination optics and receiving the output x-rays beams and generating an image from such output x-rays.

Abstract: Disclosed are apparatus and methods for determining a structure or process parameter value of a target of interest on a semiconductor wafer. A plurality of collection patterns are defined for a spatial light beam controller positioned at a pupil image plane of a metrology tool. For each collection pattern, a signal is collected from a sensor of the metrology tool, and each collected signal represents a combination of a plurality of signals that the spatial light beam controller samples, using each collection pattern, from a pupil image of the target of interest. The collection patterns are selected so that the pupil image is reconstructable based on the collection patterns and their corresponding collection signals. The collected signal for each of the collection patterns is analyzed to determine a structure or process parameter value for the target of interest.

Abstract: A method for improving computation efficiency for diffraction signals in optical metrology is described. The method includes simulating a set of spatial harmonics orders for a grating structure. The set of spatial harmonics orders is truncated to provide a first truncated set of spatial harmonics orders based on a first pattern. The first truncated set of spatial harmonics orders is modified by an iterative process to provide a second truncated set of spatial harmonics orders based on a second pattern, the second pattern different from the first pattern. Finally, a simulated spectrum is provided based on the second truncated set of spatial harmonics orders.

Abstract: Disclosed are apparatus and methods for determining a structure or process parameter value of a target of interest on a semiconductor wafer. A plurality of collection patterns are defined for a spatial light beam controller positioned at a pupil image plane of a metrology tool. For each collection pattern, a signal is collected from a sensor of the metrology tool, and each collected signal represents a combination of a plurality of signals that the spatial light beam controller samples, using each collection pattern, from a pupil image of the target of interest. The collection patterns are selected so that the pupil image is reconstructable based on the collection patterns and their corresponding collection signals. The collected signal for each of the collection patterns is analyzed to determine a structure or process parameter value for the target of interest.

Abstract: Methods and systems for optimizing measurement system parameter settings of an x-ray based metrology system are presented. X-ray based metrology systems employing an optimized set of measurement system parameters are used to measure structural, material, and process characteristics associated with different semiconductor fabrication processes with greater precision and accuracy. In one aspect, a set of values of one or more machine parameters that specify a measurement scenario is refined based at least in part on a sensitivity of measurement data to a previous set of values of the one or more machine parameters. The refinement of the values of the machine parameters is performed to maximize precision, maximize accuracy, minimize correlation between parameters of interest, or any combination thereof. Refinement of the machine parameter values that specify a measurement scenario can be used to optimize the measurement recipe to reduce measurement time and increase measurement precision and accuracy.

Abstract: Optimization of optical parametric models for structural analysis using optical critical dimension metrology is described. A method includes determining a first optical model fit for a parameter of a structure. The first optical model fit is based on a domain of quantities for a first model of the structure. A first near optical field response is determined for a first quantity of the domain of quantities and a second near optical field response is determined for a second, different quantity of the domain of quantities. The first and second near optical field responses are compared to locate a common region of high optical field intensity for the parameter of the structure. The first model of the structure is modified to provide a second, different model of the structure. A second, different optical model fit is determined for the parameter of the structure based on the second model of the structure.

Abstract: Disclosed are apparatus and methods for performing small angle x-ray scattering metrology. This system includes an x-ray source for generating x-rays and illumination optics for collecting and reflecting or refracting a portion of the generated x-rays towards a particular focus point on a semiconductor sample in the form of a plurality of incident beams at a plurality of different angles of incidence (AOIs). The system further includes a sensor for collecting output x-ray beams that are scattered from the sample in response to the incident beams on the sample at the different AOIs and a controller configured for controlling operation of the x-ray source and illumination optics and receiving the output x-rays beams and generating an image from such output x-rays.

Abstract: A novel technique for model-based metrology. A geometry of structure to be measured on a surface of a substrate is received. A tessellation of the geometry of the structure is produced. The tessellation is used to determine a vertical discretization and a horizontal discretization so as to generate a discrete model for the geometry, and scatterometry computations are performed using the discrete model. Other embodiments, aspects and features are also disclosed.

Abstract: Provided is an automated determination of an optimized parameterization of a scatterometry model for analysis of a sample diffracting structure having unknown parameters. A preprocessor determines from a plurality of floating model parameters, a reduced set of model parameters which can be reasonably floated in the scatterometry model based on a relative precision for each parameter determined from the Jacobian of measured spectral information with respect to each parameter. The relative precision for each parameter is determined in a manner which accounts for correlation between the parameters for a combination.