Methods and systems for detecting charged particles from a specimen are provided. One system includes a first repelling mesh configured to repel charged particles from a specimen having an energy lower than a first predetermined energy and a second repelling mesh configured to repel the charged particles that pass through the first repelling mesh and have an energy that is lower than a second predetermined energy. The system also includes a first attracting mesh configured to attract the charged particles that pass through the first repelling mesh, are repelled by the second repelling mesh, and have an energy that is higher than the first predetermined energy and lower than the second predetermined energy. The system further includes a first detector configured to generate output responsive to the charged particles that pass through the first attracting mesh.

Provided is a projection electron beam application apparatus suitable for use in semiconductor manufacturing lines. An electron optical system of the electron beam application apparatus includes a mirror aberration corrector 106 disposed perpendicular to an optical axis 109, a plurality of magnetic field sectors 104 by which an orbit of electrons is deviated from the optical axis to make the electrons incident on the mirror aberration corrector 106, and the orbit of the electrons emitted from the mirror aberration corrector 106 is returned to the optical axis, and a doublet lens 105 disposed between adjacent magnetic field sectors along the orbit of the electrons. The plurality of magnetic field sectors have the same deflection angle for deflecting the orbit of the electrons, and the doublet lens is disposed such that an object plane and an image plane thereof are respectively central planes of the adjacent magnetic field sectors along the orbit of the electrons.

Electron-optical devices and associated methods are disclosed. In one arrangement, an electron-optical device projects a multi-beam of sub-beams of charged particles to a sample. A plurality of plates are provided in which are defined respective aperture arrays. The plates comprise an objective lens array configured to project the sub-beams towards the sample. The aperture arrays defined in at least two of the plates each have a geometrical characteristic configured to apply a perturbation to a corresponding target property of the sub-beams. A controller controls potentials applied to the plates having the geometrical characteristics such that the applied perturbations together substantially compensate for a variation in the target property over a range of a parameter of the device.

A charged particle beam apparatus for inspecting a specimen with a plurality of beamlets is described. The charged particle beam apparatus includes a charged particle beam emitter (105) for generating a charged particle beam (11) propagating along an optical axis (A) and a multi-beamlet generation- and correction-assembly (120), including a first multi-aperture electrode (121) with a first plurality of apertures for creating the plurality of beamlets from the charged particle beam, at least one second multi-aperture electrode (122) with a second plurality of apertures of varying diameters for the plurality of beamlets for providing a field curvature correction, and a plurality of multipoles (123) for individually influencing each of the plurality of beamlets, wherein the multi-beamlet generation- and correction-assembly (120) is configured to focus the plurality of beamlets to provide a plurality of intermediate beamlet crossovers. The charged particle beam apparatus further includes an objective lens (150) for focusing each of the plurality of beamlets to a separate location on the specimen, and a single transfer lens (130) for beamlet collimation arranged between the multi-beamlet generation- and correction-assembly and the objective lens. Further, a method of inspecting a specimen with a charged particle beam apparatus is described.

A charged particle beam system is disclosed, comprising: a charged particle beam generator for generating a beam of charged particles; a charged particle optical column arranged in a vacuum chamber, wherein the charged particle optical column is arranged for projecting the beam of charged particles onto a target, and wherein the charged particle optical column comprises a charged particle optical element for influencing the beam of charged particles; a source for providing a cleaning agent; a conduit connected to the source and arranged for introducing the cleaning agent towards the charged particle optical element;

wherein the charged particle optical element comprises: a charged particle transmitting aperture for transmitting and/or influencing the beam of charged particles, and at least one vent hole for providing a flow path between a first side and a second side of the charged particle optical element,

wherein the vent hole has a cross section which is larger than a cross section of the charged particle transmitting aperture.

Further, a method for preventing or removing contamination in the charged particle transmitting apertures is disclosed, comprising the step of introducing the cleaning agent while the beam generator is active.

A multi charged particle beam irradiation apparatus includes a shaping aperture array substrate, where plural openings are formed as an aperture array, to shape multi-beams by making a region including entire plural openings irradiated by a charged particle beam, and making portions of a charged particle beam individually pass through a corresponding one of the plural openings; and a plurality of stages of lenses, arranged such that a reduction ratio of multi-beams by at least one lens of a stage before the last stage lens is larger than that of the multi-beams by the last stage lens, to correct distortion of a formed image obtained by forming an image of the aperture array by the multi-beams, and to form the image of the aperture array by the multi-beams at a height position between the last stage lens and a last-but-one stage lens, and at the surface of a target object.

A method for operating a multi-beam particle optical unit comprises includes providing a first setting of effects of particle-optical components, wherein a particle-optical imaging is characterizable by at least two parameters. The method also includes determining a matrix A, and determining a matrix S. The method further includes defining values of parameters which characterize a desired imaging, and providing a second setting of the effects of the components in such a way that the particle-optical imaging is characterizable by the parameters having the defined values.

Apertures having references edges are situated to define a sample irradiation zone and a shielded zone. The sample irradiation zone includes a portion proximate the shielded zone that is conjugate to a detector. A sample is scanned into the sample irradiation zone from the shielded zone so that the sample can remain unexposed until situated properly with respect to the detector for imaging. Irradiation exposure of the sample is reduced, permitting superior imaging.

Systems and methods for automated alignment of cathodoluminescence (CL) optics in an electron microscope relative to a sample under inspection are described. Accurate placement of the sample and the electron beam landing position on the sample with respect to the focal point of a collection mirror that reflects CL light emitted by the sample is critical to optimizing the amount of light collected and to preserving information about the angle at which light is emitted from the sample. Systems and methods are described for alignment of the CL mirror in the XY plane, which is orthogonal to the axis of the electron beam, and for alignment of the sample with respect to the focal point of the CL mirror along the Z axis, which is coincident with the electron beam.

A multi-beam apparatus for observing a sample with high resolution and high throughput and in flexibly varying observing conditions is proposed. The apparatus uses a movable collimating lens to flexibly vary the currents of the plural probe spots without influencing the intervals thereof, a new source-conversion unit to form the plural images of the single electron source and compensate off-axis aberrations of the plural probe spots with respect to observing conditions, and a pre-beamlet-forming means to reduce the strong Coulomb effect due to the primary-electron beam.