Abstract: Apparatus for X-ray scatterometry includes an X-ray source, which directs an X-ray beam to be incident at a grazing angle on an area of a surface of a sample, and an X-ray detector measures X-rays scattered from the area. A knife edge is arranged parallel to the surface of the sample in a location adjacent to the area so as to define a gap between the surface and the knife edge and to block a portion of the X-ray beam that does not pass through the gap. A motor moves the knife edge perpendicular to the surface so as to control a size of the gap. An optical rangefinder receives optical radiation reflected from the surface and outputs a signal indicative of a distance of the knife edge from the surface. Control circuitry drives the motor responsively to the signal in order to regulate the size of the gap.

Abstract: Apparatus for X-ray scatterometry includes an X-ray source, which directs an X-ray beam to be incident at a grazing angle on an area of a surface of a sample, and an X-ray detector measures X-rays scattered from the area. A knife edge is arranged parallel to the surface of the sample in a location adjacent to the area so as to define a gap between the surface and the knife edge and to block a portion of the X-ray beam that does not pass through the gap. A motor moves the knife edge perpendicular to the surface so as to control a size of the gap. An optical rangefinder receives optical radiation reflected from the surface and outputs a signal indicative of a distance of the knife edge from the surface. Control circuitry drives the motor responsively to the signal in order to regulate the size of the gap.

Abstract: A method for X-ray measurement includes, in a calibration phase, scanning a first X-ray beam, having a first beam profile, across a feature of interest on a calibration sample and measuring first X-ray fluorescence (XRF) emitted from the feature and from background areas of the calibration sample surrounding the feature. Responsively to the first XRF and the first beam profile, a relative emission factor is computed. In a test phase, a second X-ray beam, having a second beam profile, different from the first beam profile, is directed to impinge on the feature of interest on a test sample and second XRF emitted from the test sample is measured in response to the second X-ray beam. A property of the feature of interest on the test sample is computed by applying the relative emission factor together with the second beam profile to the measured second XRF.

Abstract: An apparatus includes an X-ray tube, X-ray optics, one or more coils and control circuitry. The X-ray tube is configured to direct an electron beam onto an anode so as to emit an X-ray beam. The X-ray optics which configured to receive the X-ray beam emitted from the X-ray tube and to direct the X-ray beam onto a target. The coils are configured to steer the electron beam in the X-ray tube using electrical currents flowing through the coils. The control circuitry is configured to compensate for misalignment between the X-ray tube and the X-ray optics by analyzing the X-ray beam output by the X-ray optics, and setting the electrical currents based on the analyzed X-ray beam.

Abstract: A method for X-ray Fluorescence (XRF) analysis includes directing an X-ray beam onto a sample and measuring an XRF signal excited from the sample, in a reference measurement in which the sample includes one or more first layers formed on a substrate, and in a target measurement after one or more second layers are formed on the substrate in addition to the first layers, so as to produce a reference XRF spectrum and a target XRF spectrum, respectively. A contribution of the first layers to the target XRF spectrum is reduced using the reference XRF spectrum. A parameter of at least one of the second layers is estimated using the target XRF spectrum in which the contribution of the first layers has been reduced.

Abstract: Apparatus, including a sample-support that retains a sample in a plane having an axis, the plane defining first and second regions separated by the plane. A source-mount in the first region rotates about the axis, and an X-ray source on the source-mount directs first and second incident beams of X-rays to impinge on the sample at first and second angles along beam axes that are orthogonal to the axis. A detector-mount in the second region moves in a plane orthogonal to the axis and an X-ray detector on the detector-mount receives first and second diffracted beams of X-rays transmitted through the sample in response to the first and second incident beams, and outputs first and second signals, respectively, in response to the received first and second diffracted beams. A processor analyzes the first and the second signals so as to determine a profile of a surface of the sample.

Abstract: A method includes directing an X-ray beam to be incident at a grazing angle on a location on a surface of the sample. An X-ray fluorescence excited at the location is measured. A reflection angle of the X-ray beam from the surface and a transmission angle of the X-ray beam are measured. An angle of incidence of the X-ray beam on the surface is evaluated using the measured reflection and transmission angles, and the measured X-ray fluorescence is analyzed using the evaluated angle of incidence.

Abstract: A method for inspection includes capturing an optical image of one or more features on a surface of a sample and irradiating an area of the sample containing at least one of the features with an X-ray beam. An intensity of X-ray fluorescence emitted from the sample in response to the irradiating X-ray beam is measured. The optical image is processed so as to extract geometrical parameters of the at least one of the features and to compute a correction factor responsively to the geometrical parameters. The correction factor is applied to the measured intensity in order to derive a property of the at least one of the features.

Abstract: A method for inspection includes irradiating, with a focused beam, a feature formed on a semiconductor wafer, the feature including a volume containing a first material and a cap made of a second material, different from the first material, that is formed over the volume. One or more detectors positioned at different angles relative to the feature are used to detect X-ray fluorescent photons that are emitted by the first material in response to the irradiating beam and pass through the cap before striking the detectors. Signals output by the one or more detectors at the different angles in response to the detected photons are processed in order to assess a quality of the cap.

Abstract: A method for X-ray measurement includes, in a calibration phase, scanning a first X-ray beam, having a first beam profile, across a feature of interest on a calibration sample and measuring first X-ray fluorescence (XRF) emitted from the feature and from background areas of the calibration sample surrounding the feature. Responsively to the first XRF and the first beam profile, a relative emission factor is computed. In a test phase, a second X-ray beam, having a second beam profile, different from the first beam profile, is directed to impinge on the feature of interest on a test sample and second XRF emitted from the test sample is measured in response to the second X-ray beam. A property of the feature of interest on the test sample is computed by applying the relative emission factor together with the second beam profile to the measured second XRF.

Abstract: Apparatus, including a sample-support that retains a sample in a plane having an axis, the plane defining first and second regions separated by the plane. A source-mount in the first region rotates about the axis, and an X-ray source on the source-mount directs first and second incident beams of X-rays to impinge on the sample at first and second angles along beam axes that are orthogonal to the axis. A detector-mount in the second region moves in a plane orthogonal to the axis and an X-ray detector on the detector-mount receives first and second diffracted beams of X-rays transmitted through the sample in response to the first and second incident beams, and outputs first and second signals, respectively, in response to the received first and second diffracted beams. A processor analyzes the first and the second signals so as to determine a profile of a surface of the sample.

Abstract: A method for X-ray Fluorescence (XRF) analysis includes directing an X-ray beam onto a sample and measuring an XRF signal excited from the sample, in a reference measurement in which the sample includes one or more first layers formed on a substrate, and in a target measurement after one or more second layers are formed on the substrate in addition to the first layers, so as to produce a reference XRF spectrum and a target XRF spectrum, respectively. A contribution of the first layers to the target XRF spectrum is reduced using the reference XRF spectrum. A parameter of at least one of the second layers is estimated using the target XRF spectrum in which the contribution of the first layers has been reduced.

Abstract: An apparatus includes an X-ray tube, X-ray optics, one or more coils and control circuitry. The X-ray tube is configured to direct an electron beam onto an anode so as to emit an X-ray beam. The X-ray optics which configured to receive the X-ray beam emitted from the X-ray tube and to direct the X-ray beam onto a target. The coils are configured to steer the electron beam in the X-ray tube using electrical currents flowing through the coils. The control circuitry is configured to compensate for misalignment between the X-ray tube and the X-ray optics by analyzing the X-ray beam output by the X-ray optics, and setting the electrical currents based on the analyzed X-ray beam.

Abstract: A method includes directing an X-ray beam to be incident at a grazing angle on a location on a surface of the sample. An X-ray fluorescence excited at the location is measured. A reflection angle of the X-ray beam from the surface and a transmission angle of the X-ray beam are measured. An angle of incidence of the X-ray beam on the surface is evaluated using the measured reflection and transmission angles, and the measured X-ray fluorescence is analyzed using the evaluated angle of incidence.

Abstract: A method for inspection includes capturing an optical image of one or more features on a surface of a sample and irradiating an area of the sample containing at least one of the features with an X-ray beam. An intensity of X-ray fluorescence emitted from the sample in response to the irradiating X-ray beam is measured. The optical image is processed so as to extract geometrical parameters of the at least one of the features and to compute a correction factor responsively to the geometrical parameters. The correction factor is applied to the measured intensity in order to derive a property of the at least one of the features.

Abstract: A method for analysis includes directing a converging beam of X-rays toward a surface of a sample having an epitaxial layer formed thereon, and sensing the X-rays that are diffracted from the sample while resolving the sensed X-rays as a function of angle so as to generate a diffraction spectrum including a diffraction peak and fringes due to the epitaxial layer. A characteristic of the fringes is analyzed in order to measure a relaxation of the epitaxial layer.

Abstract: Apparatus for inspection of a sample includes an X-ray source, which is configured to irradiate a location on the sample with a beam of X-rays. An X-ray detector is configured to receive the X-rays that are scattered from the sample and to output a first signal indicative of the received X-rays. A VUV source is configured to irradiate the location on the sample with a beam of VUV radiation. A VUV detector is configured to receive the VUV radiation that is reflected from the sample and to output a second signal indicative of the received VUV radiation. A processor is configured to process the first and second signals in order to measure a property of the sample.

Abstract: A method for analysis includes directing a converging beam of X-rays toward a surface of a sample having an epitaxial layer formed thereon, and sensing the X-rays that are diffracted from the sample while resolving the sensed X-rays as a function of angle so as to generate a diffraction spectrum including a diffraction peak and fringes due to the epitaxial layer. A characteristic of the fringes is analyzed in order to measure a relaxation of the epitaxial layer.

Abstract: Apparatus for inspection of a sample includes an X-ray source, which is configured to irradiate a location on the sample with a beam of X-rays. An X-ray detector is configured to receive the X-rays that are scattered from the sample and to output a first signal indicative of the received X-rays. A VUV source is configured to irradiate the location on the sample with a beam of VUV radiation. A VUV detector is configured to receive the VUV radiation that is reflected from the sample and to output a second signal indicative of the received VUV radiation. A processor is configured to process the first and second signals in order to measure a property of the sample.

Abstract: A method for analysis includes directing a converging beam of X-rays toward a surface of a sample having an epitaxial layer formed thereon, and sensing the X-rays that are diffracted from the sample while resolving the sensed X-rays as a function of angle so as to generate a diffraction spectrum including a diffraction peak and fringes due to the epitaxial layer. A characteristic of the fringes is analyzed in order to measure a relaxation of the epitaxial layer.