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.

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 method for inspecting a specimen with an array of primary charged particle beamlets in a charged particle beam device having an optical axis. The method includes generating a primary charged particle beam; illuminating a multi-aperture lens plate with the primary charged particle beam to generate the array of primary charged particle beamlets; and correcting a field curvature of the charged particle beam device with a first and a second field curvature correction electrode. The method further includes applying a voltage to the first and to the second field curvature correction electrode. At least one of the field strength provided by the first and the second field curvature correction electrode varies in a plane perpendicular to the optical axis of the charged particle beam device. The method further includes focusing the primary charged particle beamlets on separate locations on the specimen with an objective lens.

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.

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.

An electron beam apparatus addresses blanking issues resulting from sinking high-power heat onto an aperture diaphragm by evenly spreading heat on the aperture diaphragm. The apparatus can include an aperture diaphragm and a deflector that deflects the electron beam on the aperture diaphragm. The electron beam is directed at the aperture diaphragm in a pattern around the aperture. The pattern may be a circle, square, or polygon. The pattern also may include a variable locus relative to the aperture.

A multi-electron beam system that forms hundreds of beamlets can focus the beamlets, reduce Coulomb interaction effects, and improve resolutions of the beamlets. A Wien filter with electrostatic and magnetic deflection fields can separate the secondary electron beams from the primary electron beams and can correct the astigmatism and source energy dispersion blurs for all the beamlets simultaneously.

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 method for operating a particle beam microscope includes: setting a potential of a particle source; setting a potential of an object; directing a particle beam onto the object; focusing the particle beam using a particle-optical lens; providing a dependence between a value of an excitation of the particle-optical lens and a value of the potential of the object; changing a manipulated variable with the aid of an actuating element actuatable by a user; and setting the excitation of the particle-optical lens in a manner dependent on the manipulated variable. In a first mode of operation, the potential of the object is set on the basis of the excitation of the particle-optical lens in accordance with the dependence between the value of the excitation of the particle-optical lens and the value of the potential of the object.