Systems for reducing the generation of thermal magnetic field noise in optical elements of microscope systems, are disclosed. Example microscopy optical elements having reduced Johnson noise generation according to the present disclosure comprises an inner core composed of an electrically isolating material, and an outer coating composed of an electrically conductive material. The product of the thickness of the outer coating and the electrical conductivity is less than 0.01Ω.sup.−1. The outer coating causes a reduction in Johnson noise generated by the optical element of greater than 2×, 3×, or an order of magnitude or greater. In a specific example embodiment, the optical element is a corrector system having reduced Johnson noise generation. Such a corrector system comprises an outer magnetic multipole, and an inner electrostatic multipole. The inner electrostatic multipole comprises an inner core composed of an electrically isolating material and an outer coating composed of an electrically conductive material.

A multi-beam inspection apparatus including an improved source conversion unit is disclosed. The improved source conversion unit may comprise a micro-structure deflector array including a plurality of multipole structures. The micro-deflector deflector array may comprise a first multipole structure having a first radial shift from a central axis of the array and a second multipole structure having a second radial shift from the central axis of the array. The first radial shift is larger than the second radial shift, and the first multipole structure comprises a greater number of pole electrodes than the second multipole structure to reduce deflection aberrations when the plurality of multipole structures deflects a plurality of charged particle beams.

A multi-charged particle beam irradiation apparatus includes a forming mechanism to form multiple charged particle beams, a multipole deflector array to individually deflect each beam of the multiple charged particle beams so that a center axis trajectory of each beam of the multiple charged particle beams may not converge in a region of the same plane orthogonal to the direction of a central axis of a trajectory of the multiple charged particle beams, and an electron optical system to irradiate a substrate with the multiple charged particle beams while maintaining a state where the multiple charged particle beams are not converged.

An object is to provide a multipole unit capable of achieving both high positional accuracy and ease of assembling and preventing a decrease in the transmission rate of the magnetic flux. A multipole unit 109a includes a pole 1 that is made of a soft magnetic metal material, a shaft 2 that is made of a soft magnetic metal material and is magnetically connected to the pole, and a coil 3 that is wound around the shaft 2. The pole 1 is provided with a first fitting portion JP1 that forms a first recessed portion or a first protruding portion. The shaft 2 is provided with a second fitting portion JP2 that forms a second protruding portion or a second recessed portion. The first fitting portion JP1 and the second fitting portion JP2 are fitted with each other such that the pole 1 and the shaft 2 are physically separated from each other.

A method of influencing a charged particle beam (11) propagating along an optical axis (A) is described. The method includes: guiding the charged particle beam (11) through at least one opening (102) of a multipole device (100, 200) that comprises a first multipole (110, 210) with four or more first electrodes (111, 211) and a second multipole (120, 220) with four or more second electrodes (121, 221) arranged in the same sectional plane, the first electrodes and the second electrodes being arranged alternately around the at least one opening (102); and at least one of exciting the first multipole to provide a first field distribution for influencing the charged particle beam in a first manner, and exciting the second multipole to provide a second field distribution for influencing the charged particle beam in a second manner. Further, a multipole device (100, 200) with a first multipole (110, 210) and a second multipole (120, 220) provided on the same substrate as well as a charged particle beam apparatus (500) with a multipole device (100, 200) are provided.

A Wien filter and a charged particle beam imaging apparatus are provided. The Wien filter Wien filter, including a Wien filter body which includes: an electrostatic deflector, including at least one pair of electrodes, respective two electrodes in each pair of which are opposite to each other, each electrode including an electrode body constructed in an arc-shaped form, and respective electrode bodies of respective two electrodes in each pair of the at least one pair of electrodes being arranged concentrically with and opposite to each other in a diameter direction, and the at least one pair of electrodes being configured to generate respective electric fields by cooperation of the respective two electrodes in each pair of the at least one pair of electrodes, in the condition of respective bias voltages applied individually thereon; and a magnetic deflector, including at least one pair of magnetic poles, respective two magnetic poles in each pair of which are opposite to each other, each magnetic pole including a magnetic pole body constructed in an arc-shaped form, and respective magnetic pole bodies of respective two magnetic poles in each pair of the at least one pair of magnetic poles being arranged concentrically with and opposite to each other in the diameter direction, and the magnetic pole bodies of the at least one pair of magnetic poles in the magnetic deflector and the electrode bodies of the at least one pair of electrodes in the electrostatic deflector being arranged concentrically and spaced apart from each other in a circumferential direction, and the at least one pair of magnetic poles being configured to generate respective magnetic fields by cooperation of respective two magnetic poles in each pair of the at least one pair of magnetic poles; a resultant electric field formed collectively by all of the respective electric fields is perpendicular to a resultant magnetic field formed collectively by all of the respective magnetic fields; and each electrode is also provided with a respective first protrusion extending radially inwards from a radial inner side of the respective electrode body thereof, and each magnetic pole is also provided with a second protrusion extending radially inwards from a radial inner side of the respective magnetic pole body thereof.

A multi-charged particle beam irradiation apparatus includes a forming mechanism to form multiple charged particle beams, a multipole deflector array to individually deflect each beam of the multiple charged particle beams so that a center axis trajectory of each beam of the multiple charged particle beams may not converge in a region of the same plane orthogonal to the direction of a central axis of a trajectory of the multiple charged particle beams, and an electron optical system to irradiate a substrate with the multiple charged particle beams while maintaining a state where the multiple charged particle beams are not converged.

The invention relates to a method for electron microscopy. The method comprises providing an electron microscope, generating an electron beam and an image beam, adjusting one of the beam and of the beam and the image beam to reduce off-axial aberrations and correcting a diffraction pattern of the resulting modified beam. The invention also relates to a method for reducing throughput time in a sample image acquisition session in transmission electron microscopy. The method comprises providing an electron microscope, generating a beam and an image beam, adjusting one of the two to reduce off-axial aberrations and filtering the resulting modified image beam. The invention further relates to an electron microscope and to a non-transient computer-readable medium with a computer program for carrying out the methods.

A multi-beam apparatus for observing a sample with high resolution and high throughput is proposed. In the apparatus, a source-conversion unit changes a single electron source into a virtual multi-source array, a primary projection imaging system projects the array to form plural probe spots on the sample, and a condenser lens adjusts the currents of the plural probe spots. In the source-conversion unit, the image-forming means is on the upstream of the beamlet-limit means, and thereby generating less scattered electrons. The image-forming means not only forms the virtual multi-source array, but also compensates the off-axis aberrations of the plurality of probe spots.

A multi-beam apparatus for observing a sample with high resolution and high throughput is proposed. In the apparatus, a source-conversion unit forms plural and parallel images of one single electron source by deflecting plural beamlets of a parallel primary-electron beam therefrom, and one objective lens focuses the plural deflected beamlets onto a sample surface and forms plural probe spots thereon. A movable condenser lens is used to collimate the primary-electron beam and vary the currents of the plural probe spots, a pre-beamlet-forming means weakens the Coulomb effect of the primary-electron beam, and the source-conversion unit minimizes the sizes of the plural probe spots by minimizing and compensating the off-axis aberrations of the objective lens and condenser lens.