The disclosure relates to systems and method for processing images. The method includes selecting a predetermined reference structure, the predetermined reference structure having a known feature size/shape. The method also includes obtaining a reference image of the predetermined reference structure, and capturing a calibration image of the predetermined reference structure using an observation device. The calibration image includes a plurality of features. Additionally, the method includes identifying at least one portion of the plurality of features of the calibration image that include a feature size/shape substantially similar to the known feature size and shape of the predetermined reference structure. Finally, the method includes combining the identified portion of the plurality of features of the calibration image to form a stacked feature image, and determining a point spread function (PSF) of the observation device by comparing the obtained reference image with the stacked feature image.

A reference-standard device (20) for calibration of measurements of length, comprising a substrate (10) that includes a surface (10a) having at least one calibration pattern (11). According to the invention, this pattern comprises a plurality of nanometric structures (14), said nanometric structures (14) having one and the same section in the plane of said surface and having the same nanometric dimensions, in particular less than 50 nm, said nanometric structures (14) being arranged at a distance from one another by a constant pitch of nanometric length, in particular less than 50 nm, in at least one direction, said nanometric structures (14) being arranged within spatial regions (12) delimited in one or more directions in the plane of the substrate (10), said nanometric structures (14) being obtained via application to said substrate (10) of a process of nanostructuring (100) by means of a mask of block copolymers in order to make calibrations of measurements of length of the order of nanometres.

A method of determining a distortion of a field of view of a scanning electron microscope is described. The method may include: providing a sample including substantially parallel lines extending in a first direction; performing scans across the field of view of the sample along respective scan-trajectories extending in a scan direction; the scan direction being substantially perpendicular to the first direction; detecting a response signal of the sample caused by the scanning of the sample; determining a distance between a first line segment of a line and a second line segment of the line, whereby each of the first line segment and the second line segment are crossed by scan trajectories, based on the response signal; performing the previous step for multiple locations within the field of view; and determining the distortion across the field of view, based on the determined distances at the multiple locations.

The scanning charged particle beam microscope according to the present application is characterized in that, in acquiring an image of the FOV (field of view), interspaced beam irradiation points are set, and then, a deflector is controlled so that a charged particle beam scan is performed faster when the charged particle beam irradiates a position on the sample between each of the irradiation points than when the charged particle beam irradiates a position on the sample corresponding to each of the irradiation points (a position on the sample corresponding to each pixel detecting a signal). This allows the effects from a micro-domain electrification occurring within the FOV to be mitigated or controlled.

Systems and methods of measuring beam current in a multi-beam apparatus are disclosed. The multi-beam apparatus may include a charged-particle source configured to generate a primary charged-particle beam, and an aperture array. The aperture array may comprise a plurality of apertures configured to form a plurality of beamlets from the primary charged-particle beam, and a detector including circuitry to detect a current of at least a portion of the primary charged-particle beam irradiating the aperture array. The method of measuring beam current may include irradiating the primary charged-particle beam on the aperture array and detecting an electric current of at least a portion of the primary charged-particle beam.

Objective lens alignment of a scanning electron microscope review tool with fewer image acquisitions can be obtained using the disclosed techniques and systems. Two different X-Y voltage pairs for the scanning electron microscope can be determined based on images. A second image based on the first X-Y voltage pair can be used to determine a second X-Y voltage pair. The X-Y voltage pairs can be applied at the Q4 lens or other optical components of the scanning electron microscope.

A multiple beam image acquisition apparatus includes a stage to mount thereon a target object, a beam forming mechanism to form multiple primary electron beams and a measurement primary electron beam, a primary electron optical system to collectively irradiate the target object surface with the multiple primary electron beams and the measurement primary electron beam, a secondary electron optical system to collectively guide multiple secondary electron beams generated because the target object is irradiated with the multiple primary electron beams, and a measurement secondary electron beam generated because the target object is irradiated with the measurement primary electron beam, a multi-detector to detect the multiple secondary electron beams collectively guided, a measurement mechanism to measure a position of the measurement secondary electron beam collectively guided, and a correction mechanism to correct a trajectory of the multiple secondary electron beams by using a measured position of the measurement secondary electron beam.

A multi-charged particle beam inspection apparatus includes a movable stage to place thereon an inspection substrate where plural dies each with the same pattern are arranged in a predetermined direction, a pitch acquisition circuit to acquire an arrangement pitch of plural dies, a magnification control circuit to control, when imaging the inspection substrate with multi-charged particle beams while continuously moving the stage, magnification of the multi-charged particle beams to be a controlled magnification such that the arrangement pitch of the plural dies becomes a natural number (2 or greater) multiple of an imaging region cycle in the predetermined direction of plural imaging regions to be individually imaged by each beam at each arrangement position of the multi-charged particle beams, and an acquisition mechanism to acquire inspection images of the plural dies on the inspection substrate, using the multi-charged particle beams whose magnification has been controlled to be the controlled magnification.

A reference sample (41) has a step/terrace structure made of monocrystalline SiC and a surface of each terrace has first or second stack orientation. In the reference sample (41), contrast as difference in lightness and darkness between an image of a terrace with a surface directly under which the first stack orientation lies and an image of a terrace with a surface directly under which the second stack orientation lies changes according to an incident electron angle which is an angle that an electron beam emitted from a scanning electron microscope forms with a perpendicular to the terrace surface. Even when a SiC substrate has an off angle (e.g., from 1 to 8), using an inclined support base (20a) capable of correcting the off angle enables sharp contrast that reflects difference between the first and second stack orientations directly under the surface to be obtained irrespective of the off angle.

The methods and systems disclosed here detect edges of top-down images of respective cross-sections of an array of high-aspect-ratio (HAR) features. The respective cross sections are at various depths of a HAR feature along a longitudinal direction. The detected edges are re-sampled in a spatial domain at a target angular resolution. The re-sampled edges are represented as a corresponding set of harmonics in a frequency domain, each set of harmonics preserving characteristic information about a respective cross-section of the HAR feature at a certain depth. A plurality of cross-sections at the various depths of the HAR feature are reconstructed by analyzing the corresponding sets of harmonics in the frequency domain. A 3D profile of the HAR feature is generated by stitching the plurality of re-constructed cross-sections at the various depths of the HAR feature.