A method and system are presented for use in X-ray based measurements on patterned structures. The method comprises: processing data indicative of measured signals corresponding to detected radiation response of a patterned structure to incident X-ray radiation, and subtracting from said data an effective measured signals substantially free of background noise, said effective measured signals being formed of radiation components of reflected diffraction orders such that model based interpretation of the effective measured signals enables determination of one or more parameters of the patterned structure, wherein said processing comprises: analyzing the measured signals and extracting therefrom a background signal corresponding to the background noise; and applying a filtering procedure to the measured signals to subtract therefrom signal corresponding to the background signal, resulting in the effective measured signal.

A method includes obtaining a dark-field signal generated from a dark-field CT scan of an object, wherein the dark-field CT scan is at least a 360 degree scan. The method further includes weighting the dark-field signal. The method further includes performing a cone beam reconstruction of the weighted dark-field signal over the 360 degree scan, thereby generating volumetric image data. For an axial cone-beam CT scan, in one non-limiting instance, the cone-beam reconstruction is a full scan FDK cone beam reconstruction. For a helical cone-beam CT scan, in one non-limiting instance, the dark-field signal is rebinned to wedge geometry and the cone-beam reconstruction is a full scan aperture weighted wedge reconstruction. For a helical cone-beam CT scan, in another non-limiting instance, the dark-field signal is rebinned to wedge geometry and the cone-beam reconstruction is a full scan angular weighted wedge reconstruction.

A method includes obtaining a dark-field signal generated from a dark-field CT scan of an object, wherein the dark-field CT scan is at least a 360 degree scan. The method further includes weighting the dark-field signal. The method further includes performing a cone beam reconstruction of the weighted dark-field signal over the 360 degree scan, thereby generating volumetric image data. For an axial cone-beam CT scan, in one non-limiting instance, the cone-beam reconstruction is a full scan FDK cone beam reconstruction. For a helical cone-beam CT scan, in one non-limiting instance, the dark-field signal is rebinned to wedge geometry and the cone-beam reconstruction is a full scan aperture weighted wedge reconstruction. For a helical cone-beam CT scan, in another non-limiting instance, the dark-field signal is rebinned to wedge geometry and the cone-beam reconstruction is a full scan angular weighted wedge reconstruction.

Optical elements that efficiently propagate x-ray radiation over a desired energy range and reject radiation outside the desired energy range are presented herein. In one aspect, one or more optical elements of an x-ray based system include an integrated optical filter including one or more material layers that absorb radiation having energy outside the desired energy band. In general, the integrated filter improves the optical performance of an x-ray based system by suppressing reflectivity within infrared (IR), visible (vis), ultraviolet (UV), extreme ultraviolet (EUV) portions of the spectrum, or any other undesired wavelength region. In a further aspect, one or more diffusion barrier layers prevent degradation of the integrated optical filter, prevent diffusion between the integrated optical filter and other material layers, or both. In some embodiments, the thickness of one or more material layers of an integrated optical filter vary over the spatial area of the filter.

Optical elements that efficiently propagate x-ray radiation over a desired energy range and reject radiation outside the desired energy range are presented herein. In one aspect, one or more optical elements of an x-ray based system include an integrated optical filter including one or more material layers that absorb radiation having energy outside the desired energy band. In general, the integrated filter improves the optical performance of an x-ray based system by suppressing reflectivity within infrared (IR), visible (vis), ultraviolet (UV), extreme ultraviolet (EUV) portions of the spectrum, or any other undesired wavelength region. In a further aspect, one or more diffusion barrier layers prevent degradation of the integrated optical filter, prevent diffusion between the integrated optical filter and other material layers, or both. In some embodiments, the thickness of one or more material layers of an integrated optical filter vary over the spatial area of the filter.

Methods and systems for performing measurements of semiconductor structures based on high-brightness, Soft X-Ray (SXR) illumination over a small illumination spot size with a small physical footprint are presented herein. In one aspect, the focusing optics of an SXR based metrology system project an image of the illumination source onto a specimen under measurement with a demagnification of at least 1.25. In a further aspect, an illumination beam path from the x-ray illumination source to the specimen under measurement is less than 2 meters. In another aspect, SXR based measurements are performed with x-ray radiation in the soft x-ray region (i.e., 80-3000 eV). In some embodiments, SXR based measurements are performed at grazing angles of incidence in a range from near zero degrees to 90 degrees. In some embodiments, the illumination optics project an image of an illumination source onto a specimen under measurement with a demagnification of 50, or less.

Methods and systems for performing measurements of semiconductor structures based on high-brightness, Soft X-Ray (SXR) illumination over a small illumination spot size with a small physical footprint are presented herein. In one aspect, the focusing optics of an SXR based metrology system project an image of the illumination source onto a specimen under measurement with a demagnification of at least 1.25. In a further aspect, an illumination beam path from the x-ray illumination source to the specimen under measurement is less than 2 meters. In another aspect, SXR based measurements are performed with x-ray radiation in the soft x-ray region (i.e., 80-3000 eV). In some embodiments, SXR based measurements are performed at grazing angles of incidence in a range from near zero degrees to 90 degrees. In some embodiments, the illumination optics project an image of an illumination source onto a specimen under measurement with a demagnification of 50, or less.

Automated analysis of particle beam measurement results is facilitated by a device that calculates a spatial parameter distribution representing spatial structure of a sample based on a scattering pattern corresponding to projection of the spatial structure of the sample to wavenumber space, the projection being obtained by detecting scattering of a particle beam which enters the sample and intersects with the sample. The device includes a section to provide estimates for signals on the scattering pattern in association with at which point on a spatial parameter distribution of the sample interactions occur during scattering; a section to aggregate estimation results of the interaction estimation section to calculate a spatial parameter distribution of a sample matching an aggregated result; and a section to perform alternately and repeatedly estimation in the interaction estimation section and calculation in the parameter distribution calculation section in order to improve estimation accuracy in spatial parameter distributions.

Automated analysis of particle beam measurement results is facilitated by a device that calculates a spatial parameter distribution representing spatial structure of a sample based on a scattering pattern corresponding to projection of the spatial structure of the sample to wavenumber space, the projection being obtained by detecting scattering of a particle beam which enters the sample and intersects with the sample. The device includes a section to provide estimates for signals on the scattering pattern in association with at which point on a spatial parameter distribution of the sample interactions occur during scattering; a section to aggregate estimation results of the interaction estimation section to calculate a spatial parameter distribution of a sample matching an aggregated result; and a section to perform alternately and repeatedly estimation in the interaction estimation section and calculation in the parameter distribution calculation section in order to improve estimation accuracy in spatial parameter distributions.

A transmission type small-angle scattering device of the present invention includes a goniometer 10 including a rotation arm 11. The rotation arm 11 is freely turnable around a θ-axis extending in a horizontal direction from an origin with a vertical arrangement state of the rotation arm being defined as the origin, and has a vertical arrangement structure in which an X-ray irradiation unit 20 is installed on a lower-side end portion of the rotation arm 11, and a two-dimensional X-ray detector 30 is installed on an upper-side end portion of the rotation arm 11 to form a vertical arrangement structure.