An improved leveling sensor and method for adjusting a sample height in a charged-particle beam inspection system are disclosed. An improved leveling sensor comprises a light source configured to project a first pattern onto a sample and a detector configured to capture an image of a projected pattern after the first pattern is projected on the sample. The first pattern can comprise an irregularity to enable a determination of a vertical displacement of the sample.

An improved leveling sensor and method for adjusting a sample height in a charged-particle beam inspection system are disclosed. An improved leveling sensor comprises a light source configured to project a first pattern onto a sample and a detector configured to capture an image of a projected pattern after the first pattern is projected on the sample. The first pattern can comprise an irregularity to enable a determination of a vertical displacement of the sample.

Electron sources can include an electron source crystal coupled in series between opposing electrically conductive supports to form an electrically conductive path, wherein the electrical resistance of each of the electrically conductive supports is lower than the electrical resistance of the electron source crystal. Electron source crystals can include an emitting end and opposing shank end, wherein the shank end includes opposing leg portions. Electrically conductive supports can include foil supports spaced apart across a gap, wherein each of the opposing leg portions is attached to a respective foil support such that the foil supports are electrically connected to form the electrically conductive path. Particle focusing system are also disclosed. Electron sources can include an electron source crystal having an emitting end and opposing shank end, wherein the shank end is formed of a pair of opposing leg portions. Methods of manufacturing and operating electron sources are also disclosed.

Electron sources can include an electron source crystal coupled in series between opposing electrically conductive supports to form an electrically conductive path, wherein the electrical resistance of each of the electrically conductive supports is lower than the electrical resistance of the electron source crystal. Electron source crystals can include an emitting end and opposing shank end, wherein the shank end includes opposing leg portions. Electrically conductive supports can include foil supports spaced apart across a gap, wherein each of the opposing leg portions is attached to a respective foil support such that the foil supports are electrically connected to form the electrically conductive path. Particle focusing system are also disclosed. Electron sources can include an electron source crystal having an emitting end and opposing shank end, wherein the shank end is formed of a pair of opposing leg portions. Methods of manufacturing and operating electron sources are also disclosed.

A charged particle beam system includes: a charged particle beam device configured to emit a charged particle beam from a charged particle source to a sample via a charged particle optical system; and a control system configured to control the charged particle beam device. The control system scans the sample with the charged particle beam in a manner of forming a scan trajectory and determines scores of signal intensities associated with different scan directions in the scan trajectory. The control system generates, based on a relation between the scores and the different scan directions, information on at least one of a focus deviation and an aberration coefficient of the charged particle optical system.

A charged particle beam system includes: a charged particle beam device configured to emit a charged particle beam from a charged particle source to a sample via a charged particle optical system; and a control system configured to control the charged particle beam device. The control system scans the sample with the charged particle beam in a manner of forming a scan trajectory and determines scores of signal intensities associated with different scan directions in the scan trajectory. The control system generates, based on a relation between the scores and the different scan directions, information on at least one of a focus deviation and an aberration coefficient of the charged particle optical system.

A pattern inspection apparatus includes a secondary electron image acquisition mechanism to include a deflector deflecting multiple primary electron beams and a detector detecting multiple secondary electron beams, and acquire a secondary electron image corresponding to each of the multiple primary electron beams by scanning a target object with a pattern thereon with the multiple primary electron beams by the deflector, and detecting the multiple secondary electron beams from the target object by the detector, a storage device to store individual correction kernels each generated for individually adjusting a secondary electron image corresponding to each primary electron beam concerning a reference pattern to be commensurate with a reference blurred image, and a correction circuit to correct, by correspondingly using the individual correction kernel, the secondary electron image corresponding to each primary electron beam acquired from the inspection target object.

A method of automatically focusing a charged particle beam on a surface region of a sample is provided. The method includes acquiring a plurality of images for a corresponding plurality of focusing strength values; calculating a plurality of sharpness values based on the plurality of images, the plurality of sharpness values are calculated with a sharpness function provided as a sum in a frequency space based on the plurality of images; and determining subsequent focusing strength values of the plurality of focusing strength values with a golden ratio search algorithm based one the calculated sharpness values.

A method of automatically focusing a charged particle beam on a surface region of a sample is provided. The method includes acquiring a plurality of images for a corresponding plurality of focusing strength values; calculating a plurality of sharpness values based on the plurality of images, the plurality of sharpness values are calculated with a sharpness function provided as a sum in a frequency space based on the plurality of images; and determining subsequent focusing strength values of the plurality of focusing strength values with a golden ratio search algorithm based one the calculated sharpness values.

A method for operating a particle beam microscope comprises setting a distance of an object from an objective lens, setting an excitation of the objective lens, setting an excitation of a double deflector to a first setting such that a particle beam is incident on the object at a first orientation, and recording a first particle-microscopic image at these settings. The method also comprises setting the excitation of the double deflector to a second setting such that the particle beam is incident on the object at a second orientation which differs from the first orientation; and recording a second particle-microscopic image at the second setting of the double deflector. Thereupon, a new distance of the object from the objective lens is determined based on an analysis of the first and second particle-microscopic images, and the distance of the object from the objective lens is set to the new distance.