The disclosure relates to charged-particle multi-beam columns and multi-beam column arrays. In one arrangement, a sub-beam defining aperture array forms sub-beams from a beam of charged particles. A collimator array collimates the sub-beams An objective lens array projects the collimated sub-beams onto a sample. A detector detects charged particles emitted from the sample. Each collimator is directly adjacent to one of the objective lenses. The detector is provided in a plane down-beam from the sub-beam defining aperture array.

A charged particle assessment tool including: an objective lens configured to project a plurality of charged particle beams onto a sample, the objective lens having a sample-facing surface defining a plurality of beam apertures through which respective ones of the charged particle beams are emitted toward the sample; and a plurality of capture electrodes, each capture electrode adjacent a respective one of the beam apertures, configured to capture charged particles emitted from the sample.

A particle beam system includes a multi-source system. The multi-source system comprises an electron emitter array as a particle multi-source. The inhomogeneous emission characteristics of the various emitters in this multi-source system are correctable, or pre-correctable for subsequent particle-optical imaging, via particle-optical components that are producible via MEMS technology. A beam current of the individual particle beams is adjustable in the multi-source system.

The present disclosure provides a method of manufacturing an electron source. The method includes forming one or more fixed emission sites on at least one needle tip, the fixed emission sites including a reaction product formed by metal atoms on a surface of the needle tip and gas molecules.

The present disclosure provides a method of regenerating an electron source, the electron source including at least one emission site fixed on a needle tip, and the emission site including a reaction product formed by metal atoms and gas molecules. The method includes regenerating the electron source in situ if an emission capability of the electron source satisfies a regeneration condition.

The present disclosure provides an electron source, including one or more tips, wherein at least one of the tips comprises one or more fixed emission sites, wherein at least one of the tips includes one or more fixed emission sites, wherein the emission sites includes a reaction product of metal atoms on a surface of the tip with gas molecules.

A light modulated electron source utilizes a photon-beam source to modulate the emission current of an electron beam emitted from a silicon-based field emitter. The field emitter's cathode includes a protrusion fabricated on a silicon substrate and having an emission tip covered by a coating layer. An extractor generates an electric field that attracts free electrons toward the emission tip for emission as part of the electron beam. The photon-beam source generates a photon beam including photons having an energy greater than the bandgap of silicon, and includes optics that direct the photon beam onto the emission tip, whereby each absorbed photon creates a photo-electron that combines with the free electrons to enhance the electron beam's emission current. A controller modulates the emission current by controlling the intensity of the photon beam applied to the emission tip. A monitor measures the electron beam and provides feedback to the controller.

A light modulated electron source utilizes a photon-beam source to modulate the emission current of an electron beam emitted from a silicon-based field emitter. The field emitter's cathode includes a protrusion fabricated on a silicon substrate and having an emission tip covered by a coating layer. An extractor generates an electric field that attracts free electrons toward the emission tip for emission as part of the electron beam. The photon-beam source generates a photon beam including photons having an energy greater than the bandgap of silicon, and includes optics that direct the photon beam onto the emission tip, whereby each absorbed photon creates a photo-electron that combines with the free electrons to enhance the electron beam's emission current. A controller modulates the emission current by controlling the intensity of the photon beam applied to the emission tip. A monitor measures the electron beam and provides feedback to the controller.

A multi-electron beam imaging apparatus is disclosed herein. An example apparatus at least includes an electron source for producing a precursor electron beam, an aperture plate comprising an array of apertures for producing an array of electron beams from said precursor electron beam, an electron beam column for directing said array of electron beams onto a specimen, where the electron beam column is configured to have a length less than 300 mm, and where the electron beam column comprises a single individual beam crossover plane in which each of said electron beams forms an intermediate image of said electron source, and a single common beam crossover plane in which the electron beams in the array cross each other.

In a first cross section along an electron ray that passes between an inner curved surface and an outer curved surface of a beam bender, the curvature of the surfaces are fixed, and the center of the curvature of the surfaces are set so as to match each other. In a second cross section perpendicular to the electron ray, the curvature of the surfaces are fixed, and the center of curvature of the surfaces are set so as to match each other. The radius of the curvature of the surface in the second cross section is set to be larger than that of the surface in the first cross section. The radius of curvature of the surface in the second cross section is set to be larger than that of the surface in the first cross section.