Particle optical arrangement, in particular multi-beam particle microscope, having magnet arrangement for separating primary particle optical beam path from secondary particle optical beam path

Abstract

A particle optical arrangement, in particular a multi-beam particle microscope, having a magnet arrangement to separate a primary particle optical beam path from a secondary particle optical beam path is disclosed. The magnet arrangement has: a first magnetic field region through which a primary particle optical beam path and a secondary particle optical beam path pass for separating the primary particle optical beam path and the secondary particle optical beam path from each other; and a second magnetic field region disposed in the primary particle optical beam path and not disposed in the secondary particle optical beam path, the second magnetic field region being disposed upstream of the first magnetic field region with respect to the primary particle optical beam path, the first magnetic field region and the second magnetic field region substantially deflect the primary particle optical beam path in different directions; and a third magnetic field region disposed in the primary particle optical beam path and not disposed in the secondary particle optical beam path, the third magnetic field region being disposed upstream of the second magnetic field region with respect to the primary particle optical beam path, and the first and third magnetic field regions substantially deflect the primary particle optical beam path in the same direction. The direction of entry of the primary particle optical beam path into the third magnetic field region and the direction of exit of the primary particle optical beam path from the first magnetic field region are parallel to each other and are not offset.

Description

Technical Field

[0001] The present invention relates to a particle optical arrangement with an improved beam splitter. In particular, the present invention relates to a particle optical arrangement with a magnet arrangement to separate a primary particle optical beam path from a secondary particle optical beam path, in particular a multi-beam particle microscope. Background Art

[0002] With the continuous development of ever smaller and more complex microstructures such as semiconductor components, there is a need to further develop and optimize planar production technology and inspection systems for the production and inspection of small-sized microstructures. For example, the development and production of semiconductor components requires monitoring the design of test wafers, and planar production technology requires process optimization for reliable production with high throughput. In addition, there is a recent need to analyze semiconductor wafers for reverse engineering and customer-specific individual construction of semiconductor components. Therefore, an inspection device that can be used with high throughput is required to inspect microstructures on wafers with high accuracy.

[0003] Typical silicon wafers for the production of semiconductor components have a diameter of up to 300 mm. Each wafer is divided into 30 to 60 repeating areas ("dies") with a size of up to 800 mm2. Semiconductor devices include multiple semiconductor structures, which are produced in layers on the surface of the wafer by planar integration technology. Due to the production process, semiconductor wafers usually have a flat surface. The structural dimensions of the integrated semiconductor structures in this case extend from a few μm to a critical dimension (CD) of 5 nm, and the structural dimensions will become smaller in the near future; in the future, the structural dimensions or critical dimensions (CD) are expected to be less than 3 nm, such as 2 nm, or even less than 1 nm. In the case of the above-mentioned small structural dimensions, dimensional defects of critical dimensions must be quickly identified in very large areas. For several applications, the specifications for the measurement accuracy provided by the inspection equipment are even higher, for example by a factor of two or one order of magnitude. For example, the width of semiconductor features must be measured with an accuracy of less than 1 nm, such as 0.3 nm or even less, and the relative position of semiconductor structures must be determined with an overlay accuracy of less than 1 nm, such as 0.3 nm or even less.

[0004] MSEM is a multi-beam scanning electron microscope, which is a relatively new development in the field of charged particle systems (charged particle microscopes (CPMs)). For example, multi-beam scanning electron microscopes are disclosed in US 7 244 949 B2 and US2019 / 0355544 A1. In the case of a multi-beam electron microscope or MSEM, a sample is irradiated simultaneously with multiple individual electron beams, which are arranged in a field or raster. For example, 4 to 10,000 individual electron beams can be provided as a primary radiation, wherein each individual electron beam is separated from adjacent individual electron beams by a pitch of 1 to 200 microns. For example, MSEM has about 100 separate individual electron beams ("beamlets"), which are, for example, arranged in a hexagonal raster, wherein the individual electron beams are separated by a pitch of about 10 μm. The multiple charged individual particle beams (primary beams) are focused on the surface of the sample to be inspected through a shared objective lens. For example, the sample can be a semiconductor wafer, which is fixed to a wafer holder mounted on a movable stage. During the irradiation of the wafer surface with a charged primary individual particle beam, interaction products, such as secondary electrons or backscattered electrons, are emitted from the wafer surface. Their starting points correspond to those positions on the sample (each of the multiple primary individual particle beams is focused on it). The number and energy of the interaction products depend on the material composition and the topography of the wafer surface. The interaction products form multiple secondary individual particle beams (secondary beams), which are bunched by a shared objective lens, and due to the projection imaging system of the multi-beam inspection system, these secondary individual particle beams are incident on a detector configured in a detection plane. The detector includes multiple detection areas, each detection area includes multiple detection pixels, and the detector captures the intensity distribution of each secondary individual particle beam. In this process, an image field of, for example, 100 μm×100 μm is obtained.

[0005] The prior art multi-beam electron microscope comprises a series of electrostatic and magnetic elements. At least some of the electrostatic and magnetic elements are adjustable to adapt the focus position and stigmation of the multiple charged individual particle beams. In addition, the prior art multi-beam system with charged particles comprises at least one intersection plane of the primary or secondary charged individual particle beams. In addition, the prior art system comprises a detection system to make adjustment easier. The prior art multi-beam particle microscope comprises at least one beam deflector ("deflection scanner") for scanning an area of ​​the sample surface by a plurality of primary individual particle beams in a bunched manner to obtain an image field of the sample surface. .

[0006] A so-called beam splitter (or alternatively a beam separator or beam splitter) is used to separate the particle optical beam path of the primary beam from the particle optical beam path of the secondary beam. In this case, the separation is achieved by a special configuration of magnetic and / or electrostatic fields, for example by a Wien filter.

[0007] Imaging aberrations usually arise due to the use of particle optical components. When beam splitters are used, aberrations within the particle optical imaging range also occur and need to be corrected as much as possible. Ideally, imaging aberrations of all individual particle beams should be avoided or corrected. As the image field becomes more and more extensive within the particle optical imaging range, correction usually becomes more and more important. In the case of multi-beam particle microscopes operating with multiple individual particle beams (multi-image field, so-called mFOV), the image field can be particularly extensive.

[0008] To correct aberrations caused by the beam splitter of a multi-beam particle microscope, EP 1 668 662 B1 discloses providing another sector magnetic field in the primary path upstream of the actual sector magnetic field. Aberrations in the secondary path are corrected by up to three additional sector magnetic fields in the auxiliary path.

[0009] US 9,153,413 B2 discloses another beam splitter for a multi-beam particle microscope, in which the aberrations caused by the beam splitter are corrected. The beam splitter operates according to the Wiener filter principle. To correct the aberrations, the alignment or tilt of the individual particle beams is corrected one by one or individually after passing through the beam splitter by means of a multi-deflector array.

[0010] As the resolution requirements for multibeam particle microscopy continue to increase, so too do the requirements for aberration correction. Therefore, an overall improvement in correcting the imaging aberrations caused by the beam splitter is required. Summary of the invention

[0011] It is therefore an object of the present invention to provide a particle optical arrangement, and in particular a multibeam particle microscope, by means of which aberrations caused by a beam splitter, occurring in particular in the primary path, can be better corrected.

[0012] This object is achieved by the subject-matter of the independent patent claims.

[0013] Advantageous embodiments of the invention are evident from the dependent claims.

[0014] This patent application claims the priority of German patent application with application number 10 2022 120 496.0 filed on August 12, 2022, the entire disclosure of which is incorporated by reference into the present patent application.

[0015] In the case of a multi-beam particle microscope, the aberrations that may typically occur include, for example, spherical aberration, astigmatism, coma, field curvature, distortion, chromatic aberration or dispersion, etc. In the case of a multi-beam particle microscope, as described in EP 1 668 662 B1, with the above-described configuration of the beam splitter or the fan-shaped magnetic field or magnetic field region briefly described above, the imaging of a plurality of first individual particle beams into the object plane as a whole can already be substantially free of astigmatism in the first order and substantially free of distortion in the first order, and also free of dispersion. This should be possible. The complete disclosure of EP 1 668 662 B1 is incorporated herein by reference.

[0016] Therefore, according to a first approach, attempts are made to provide an existing beam splitter with additional correction elements while leaving the beam splitter itself substantially unchanged. For example, this approach is used to perform field curvature correction.

[0017] Surprisingly, however, more recent, more precise tests (high-precision measurements known as focus maps) have shown that during particle optical imaging, the main residual error remaining is usually not field curvature but field inclination. In the case of field inclination, the focus position of the first individual particle beam relative to the (ideal) object plane varies linearly with the distance from the optical axis; in the case of field curvature, by contrast, the focus position varies quadratically with the distance from the optical axis. Several compensators for correcting field inclination have already been proposed in DE 2021200 799 B3.

[0018] For example, unlike field curvature, field tilt is a non-rotationally symmetric aberration. In the case of existing beam splitters, possible causes of non-rotationally symmetric aberrations can be found in the symmetry violation in the case of the beam splitter. The angle between the optical axis when the primary beam enters the beam splitter and the optical axis when the primary beam exits the beam splitter ("skew angle") may lead to this symmetry violation. Therefore, the present invention proposes a modified design for the beam splitter itself or the associated magnet configuration. In particular, the field tilt can be corrected at the same time, or even does not occur in the case of a suitable choice of the beam splitter design: this is because the field tilt is essentially the result of small path differences between the individual particle beams when passing through the beam splitter. According to the inventors' inspection, in the case of the design according to EP 1 668 662 B1, these path differences are decisively caused by the angle (so-called "skew angle") between the optical axis when the primary beam enters the beam splitter and the optical axis when the primary beam exits the beam splitter. As a result, the primary beam column is slightly tilted relative to the remaining structure or the lower area of ​​the column in the area of ​​the objective and the sample. Likewise, non-precisely collimated entrances of individual particle beams into the beam splitter may result in path length differences, as may tilting of the depressions of magnetic field regions or sectors relative to the optical axis.

[0019] Therefore, according to the present invention, an aligned optical axis design for a beam splitter is proposed, which, in addition, provides at least as many or even more manipulation parameters for correcting aberrations than designs known in the prior art. In the case of the aligned optical axis design, no bevel is required, which, in addition to improving the imaging properties of the beam splitter, provides great advantages during the manufacture and adjustment of the multi-beam particle microscope.

[0020] According to a first aspect of the invention, the invention thus relates to a particle optical arrangement for providing a primary particle optical beam path for a plurality of first individual particle beams, which emanate from a multibeam particle generator and are directed towards an object positionable in an object plane of the arrangement, and for providing a secondary particle optical beam path for a plurality of second individual particle beams, which emanate from the object,

[0021] Wherein the particle-optical configuration has a magnet configuration comprising:

[0022] a first magnetic field region through which the primary particle optical beam path and the secondary particle optical beam path pass, for separating the primary particle optical beam path and the secondary particle optical beam path from each other,

[0023] a second magnetic field region disposed in the primary particle optical beam path and not disposed in the secondary particle optical beam path, the second magnetic field region being disposed upstream of the first magnetic field region relative to the primary particle optical beam path, and the first magnetic field region and the second magnetic field region substantially deflect the primary particle optical beam path in different directions;

[0024] a third magnetic field region disposed in the primary particle optical beam path and not disposed in the secondary particle optical beam path, the third magnetic field region being disposed upstream of the second magnetic field region relative to the primary particle optical beam path, and the first and third magnetic field regions substantially deflect the primary particle optical beam path in the same direction,

[0025] The entry direction of the primary particle optical beam path into the third magnetic field region and the departure direction of the primary particle optical beam path from the first magnetic field region are substantially parallel to each other and substantially not offset. As a result of this condition, the magnet configuration therefore has an "aligned optical axis" for the primary particle optical beam path. This aligned optical axis characteristic can be obtained very accurately; in the case of the optical axis alignment characteristic, the error or angle between the entry direction of the primary particle optical beam path into the third magnetic field region and the departure direction of the primary particle optical beam path from the first magnetic field region is less than or equal to 4mrad, preferably less than or equal to 1mrad, or optimally less than or equal to 0.1mrad. The error of the non-offset characteristic is also very small, for example no more than + / -0.6mm, preferably + / -0.3mm, + / -0.1mm or even + / -0.05mm.

[0026] For example, if the particle optical arrangement is a multi-beam particle microscope, then, unlike the prior art, the first plurality of individual particle beams can reach the sample even if the beam splitter or the magnet arrangement is switched off. This makes it substantially easier to check the intended operation of the magnet arrangement and other particle optical imaging elements. This also substantially simplifies the manufacturing of the multi-beam particle microscope as a whole.

[0027] Using magnetic fields pointing in substantially the same direction, a deflection of the particle beam in substantially the same direction can be achieved; in this case, the magnetic field strengths in the two magnetic field regions may be the same or different.

[0028] Using magnetic fields pointing in substantially opposite directions, a deflection of the particle beam in substantially different directions can be achieved; in this case, the magnetic field strengths in the two magnetic field regions may be substantially the same or different.

[0029] Since the primary path of the particle optical configuration provides one more magnetic field region than the prior art, the magnet configuration also provides enough options for the optimization method for the purpose of correcting aberrations. This is because there are at least as many independent operating parameters as the previous system. The manipulation parameters for the magnet configuration are particularly the positions (height or z position) of the entry point and the exit point for entering / leaving each magnetic field region, and the associated entry or exit angle. By defining these manipulation parameters, the corresponding arc length in the magnetic field region can be set (for a given magnetic field and a given kinetic energy of the charged particles), wherein the first individual charged particle beam moves through the magnetic field region along this arc length.

[0030] The magnetic field regions themselves can be formed in a manner known per se. They are particularly designed to form a uniform magnetic field, wherein the direction of the magnetic field is oriented orthogonal to the direction of movement of the first individual particle beam. For example, each magnetic field region can be formed by two spaced apart plates of magnetizable material, each plate having a milled recess into which a current conductor or coil has been inserted. However, other specific embodiments are also possible.

[0031] The first individual charged particle beam can be, for example, electrons, positrons, muons or ions or other charged particles. The second individual charged particle beam can be the mirror image particles of the first individual charged particle beam; they can be secondary electrons or backscattered electrons. In principle, the particle optical configuration can thus be used flexibly.

[0032] The terms primary particle optical beam path and secondary particle optical beam path are used according to the routine of the art. However, it should be noted here that a primary particle optical beam path, just like a secondary particle optical beam path, is a path describing a plurality of first or second individual particle beams. However, for simplicity, depending on the context, the terms "primary particle optical beam path" and "secondary particle optical beam path" may also refer only to individual particle beams or a central beam moving along the optical axis of the system.

[0033] According to a preferred specific embodiment of the present invention, the first drift region substantially without magnetic field is configured in the primary particle optical beam path between the first magnetic field region and the second magnetic field region; and / or the second drift region substantially without magnetic field is configured in the primary particle optical beam path between the second magnetic field region and the third magnetic field region. In this case, the first drift region and the second drift region can have different lengths and different orientations. Providing drift regions between magnetic field regions provides advantages in the design of particle optical configuration, especially in the case of a given entry point and a given exit point of the particle optical configuration: this is because this situation causes the magnet configuration to have more independent manipulation parameters, providing more options for correcting imaging aberrations. In addition, the larger distance between the magnetic field regions helps to reduce or avoid the interaction effect between the magnetic field regions. In addition, it is also possible to promote the spatial separation between the primary particle beam and the secondary particle beam.

[0034] According to another preferred embodiment of the present invention, the magnet configuration has a fourth magnetic field region which is arranged in the primary particle optical beam path and not arranged in the secondary particle optical beam path,

[0035] wherein the fourth magnetic field region is arranged upstream of the second magnetic field region and downstream of the third magnetic field region relative to the primary particle optical beam path, and

[0036] The fourth magnetic field region and the second magnetic field region substantially deflect the primary particle optical beam path in the same direction.

[0037] The advantage of providing a fourth magnetic field region is that more manipulation parameters are provided for correcting aberrations. These can be up to four additional manipulation parameters (e.g., an entrance height into the magnetic field region and an exit height out of the magnetic field region, and a magnetic field region or groove inclination relative to the optical axis of the primary particle optical beam path when entering or leaving).

[0038] According to another preferred embodiment of the present invention, the particle optical configuration has a first drift region substantially free of magnetic field, which is configured in the primary particle optical beam path between the first magnetic field region and the second magnetic field region. In addition, or as an alternative, the particle optical configuration has a second drift region substantially free of magnetic field, which is configured in the primary particle optical beam path between the second magnetic field region and the fourth magnetic field region. In addition, or as an alternative, the particle optical configuration has a third drift region substantially free of magnetic field, which is configured in the primary particle optical beam path between the fourth magnetic field region and the third magnetic field region. Also in this specific embodiment variation of the present invention, providing a drift region helps to increase the number of parameters of the magnet configuration that can be adjusted independently of each other.

[0039] According to another preferred embodiment of the present invention, the magnet is configured in the primary particle optical beam path without being designed to deflect the primary particle optical beam path by more than 2 °, preferably more than 1 °, and most preferably more than 0.5 ° of other magnetic field regions. In other words, according to this preferred embodiment, exactly three magnetic field regions or exactly four magnetic field regions should be provided in the primary particle optical beam path. The advantage of limiting the number of magnetic field regions in the primary particle optical beam path is that multiple first individual particle beams will not be strongly focused as a whole during the movement through the magnet configuration. This is because, due to the occurrence of a quadrupole field, the first individual charged particle beams all experience focusing when entering or leaving each magnetic field region, although the focusing is weaker. At the same time, limiting the magnetic field region to a relatively small number also limits this focusing that is not expected to occur in principle.

[0040] According to another preferred embodiment of the invention, the magnet arrangement of the particle optical arrangement is arranged such that no substantial path differences occur when the plurality of first individual particle beams pass through the magnet arrangement. This eliminates or reduces field tilt, for example.

[0041] According to a preferred specific embodiment of the present invention, the magnet configuration of the particle optical configuration has a symmetry plane, and when passing through the magnet configuration, the primary particle optical beam path is mirror-symmetric with respect to the symmetry plane. Therefore, this symmetry plane can be located at an intermediate position between the entry point of the primary particle optical beam path into the magnet configuration as a whole and the exit point of the secondary particle optical beam path leaving the magnet configuration as a whole. If the magnet configuration as a whole has exactly three magnetic field regions, the symmetry plane intersects with the second magnetic field region. If the magnet configuration as a whole has four magnetic field regions, the symmetry plane is configured between the second magnetic field region and the fourth magnetic field region. The symmetry condition about the symmetry plane is related to the particle optical beam path, in particular to the chief ray; it is not automatically related to the design of the magnetic field region itself. However, some magnetic field regions can have the same or mirror-identical dimensions, which can provide advantages from a manufacturing perspective. In addition, due to the symmetrical design of the magnet configuration, five second-order aberration terms (out of a total of 18 linearly independent second-order aberration terms) are eliminated. In general, each symmetry requirement reduces the number of manipulation parameters that can be adjusted independently of each other. However, if, as already described in detail above, corresponding drift paths are provided in the magnet configuration, then in principle a sufficient number of actuation parameters which can be adjusted independently of one another remain.

[0042] According to a preferred embodiment of the invention, during operation of the particle optical arrangement, the direction of the magnetic field in all magnetic field regions of the magnet arrangement is substantially orthogonal to the optical axis of the primary particle optical beam path and the magnetic field is substantially uniform. Thus, the trajectory in the magnet arrangement described by the first individual particle beam (a circular trajectory or a trajectory having a radius r B The spiral trajectory of the track r can be adjusted in a better and more precise manner. For example, the following can be applied to the track radius r B :0.1m≤r B ≤10.0m.

[0043] According to another preferred embodiment of the present invention, during operation of the particle optical arrangement, the uniform magnetic fields in the magnetic field regions in the primary particle optical beam path each have an absolute value of the magnetic field strength, and each magnetic field is assigned a sign, the sign characterizing the direction of the magnetic field, and

[0044] The product of the signed absolute value of the magnetic field intensity and the relevant arc length in the magnetic field region is substantially zero to an approximate value in the primary particle optical beam path for all magnetic field regions, and the primary particle optical beam path travels along the arc length in the magnetic field region. This condition is applicable to the first approximation of the central beam. For the alignment optical axis characteristic of the magnet configuration, this is a necessary but not sufficient condition. The entry direction of the primary particle optical beam path into the third magnetic field region is substantially parallel to each other with the departure direction of the primary particle optical beam path from the first magnetic field region. However, in principle, an offset may still occur. The latter can be eliminated by appropriately selecting a drift path or its length. For example, if there are three magnetic field regions in total and if the first drift region and the second drift region are respectively configured between two magnetic field regions, the lengths of the two drift regions must be the same so that there is no offset. For example, if magnet configuration provides four magnetic field regions in total, and if corresponding drift region is provided between two magnetic field regions, the length of the first drift region and the last drift region can be selected as, for example, the same, and the central drift region extends parallel to the entry direction or the exit direction of (having shown vector consistency) of the primary particle optical beam path entering / leaving the magnet configuration. Quite generally, for the magnet configuration with the alignment optical axis relative to the primary particle optical beam path, the vector sum of the overall drift path produces a vector, which is a multiple of the entry direction of the primary particle optical beam path entering the magnet configuration as a whole. In any case, if the magnetic field intensity in all magnetic field regions is the same, this description is applicable. In addition to the above-mentioned conditions of the particle optical beam path of the central beam, the magnet configuration is preferably designed to, when traveling through the magnet configuration, there is substantially no path length difference between each first individual particle beam, even when the first individual particle beam diverges or converges to enter the magnet configuration and / or when the first individual particle beam diverges or converges from the magnet configuration The off-axis beam in the case of emitting.

[0045] According to a preferred specific embodiment of the present invention, during the operation of the particle optical configuration, the following relationship applies to the splitting angle γ≥2°, preferably γ≥5°, and optimally γ≥10° of the overall deflection of the primary particle optical beam path in the first magnetic field region. In this case, the splitting angle is a measure of the maximum possible separation of the primary particle optical beam path from the secondary particle optical beam path. The splitting angle γ cannot be selected too small, otherwise other magnetic field regions of the secondary particle optical beam path cannot be smoothly integrated into the magnet configuration of the particle optical configuration. For example, other magnetic field regions that should be specifically allocated to the secondary particle optical beam path may collide with magnetic field regions of the primary particle optical beam path. For example, this may lead to crosstalk between the various magnetic field regions.

[0046] According to another preferred specific embodiment of the present invention, the overall length of the magnet configuration is defined by the distance between the entry point of the primary particle optical beam path entering the third magnetic field region and the exit point of the primary particle optical beam path leaving the first magnetic field region, which is less than or equal to 1.0m, preferably less than or equal to 0.5m or most preferably less than or equal to 0.3m.

[0047] According to another preferred specific embodiment of the present invention, each magnetic field region has an entrance region having an entry tilted primary particle optical beam path, and an exit region having an exit tilted primary particle optical beam path, wherein the exit tilt of the first magnetic field region is substantially 0°. Here, the entry tilt is defined as the angle at which the alignment of the entrance region deviates from the normal of the optical axis of the primary particle optical beam path, and the exit tilt is defined as the angle at which the alignment of the exit region deviates from the normal of the primary particle optical beam path. The departure tilt of the first magnetic field region is specified to be substantially 0°, ensuring that the optical axis of the objective lens further down in the primary particle optical beam path can correspond to or coincide with the exit direction of the primary particle optical beam path. This is beneficial to other settings of the particle optical configuration as a whole.

[0048] According to a preferred embodiment of the present invention, the entry inclination of the third magnetic field region is substantially 0°. This is also further advantageous for other configurations of the particle optical configuration in the primary particle optical beam path, while the 0° inclination can represent a condition for establishing symmetry in the magnet configuration aligned with the optical axis.

[0049] According to a preferred specific embodiment of the present invention, the particle optical configuration also has a deflection configuration, which is configured upstream of the third magnetic field region in the direction of the primary particle optical beam path, and is configured to set the entry direction of the primary particle optical beam path into the third magnetic field region, and thus set the required entry tilt 0°, with an accuracy of + / -0.1° or better, especially + / -0.05° or better, or + / -0.025° or better, and is configured to set the entry position of the primary particle optical beam path into the third magnetic field region, with an accuracy of + / -0.3mm or better, especially + / -0.1mm or better or even + / -0.05mm or better. Preferably, the deflection configuration includes two adjustment deflectors, which can be adjusted accurately and independently of each other, so that both the offset and skew of the first individual particle beam when entering the magnet configuration can be set accurately and independently of each other. This prevents a possible recurrence of beamsplitter aberrations which have in fact been corrected by means of the design of the magnet arrangement, such as field tilt in the case of tilted or offset beam incoupling, field astigmatism, global astigmatism or other second- or third-order aberrations.

[0050] According to a preferred embodiment of the present invention, the entry inclination of the first magnetic field region is selected so that the departure angle σ of the secondary particle optical beam path from the first magnetic field region is limited to σ≤35°, preferably σ≤25° or optimally σ≤15°. This avoids large aberration aggregation when emitting from the first magnetic field region, and creates additional installation space for possible additional secondary path magnetic field regions in the gap between the first magnetic field region and the second magnetic field region. More details on this are given below.

[0051] According to a preferred embodiment of the invention, the magnet arrangement has a beam tube arrangement in which the primary particle optical beam path extends within the magnet arrangement, wherein the beam tube arrangement has a torus topological form. As a result, the optical axis alignment property of the magnet arrangement can be used for adjustment purposes when a primary path beam splitter is turned off or when a magnetic field region in the primary particle optical beam path is turned off. The torus topology very generally describes two branches of a beam tube arrangement, wherein the primary particle optical beam path can branch at a first branch and can couple back at a second branch when the magnetic field region is turned off.

[0052] According to a preferred embodiment of the invention, during operation of the particle optical arrangement, the following relationship applies to the fill factor F of the beam tube arrangement: F≤50%, preferably F≤30%, or optimally F≤10%. In this case, the fill factor is given as the ratio of the maximum diameter S of the beam (the sum of the individual particle beams at a time) to the inner diameter R of the beam tube or beam tube arrangement. In this case, the beam tube is made of a non-magnetic material. For a given maximum diameter S of the beam, the inner diameter R of the beam tube can be determined accordingly. This minimizes the contamination of the beam tube due to interaction with the charged particle beam during operation, in order to avoid undesired beam deflections due to charged contamination points on the inside of the beam tube.

[0053] According to an alternative specific embodiment of the present invention, the magnet configuration does not include a beam tube configuration in which a primary particle optical beam path extends within the magnet configuration. The beam tube configuration used in the prior art limits the manipulation space of individual particle beams when passing through the magnet configuration. However, if it is possible to check the primary particle optical beam path in the state where the magnet configuration is closed in the alignment optical axis design of the magnet configuration according to the present invention, the limitation of the manipulation space of the particle beam brought by the beam tube configuration may be an obstacle. For example, more details can be collected from GB000002519511A, the complete disclosure of which is incorporated by reference in this patent application. According to a preferred specific embodiment of the present invention, the magnet configuration therefore has a vacuum chamber, and the primary particle optical beam path and / or the secondary particle optical beam path extend within the magnet configuration in the vacuum chamber. The free mobility required for individual particle beams is provided in this vacuum chamber. In principle, each magnetic field region can be configured or fixed in a vacuum chamber in a manner known per se.

[0054] According to a preferred embodiment of the present invention, the magnet is configured to have at least two additional magnetic field regions in the secondary particle optical beam path after passing through the first magnetic field region, and in the case of a change in energy of the secondary particles, whose path forms the second particle optical beam path, the at least two additional magnetic field regions are configured to accurately couple the particle optical axis in the secondary beam path, in terms of offset and angle, into the downstream projection optical unit. For example, the energy of the secondary particle change can be the result of modifying the landing energy setting.

[0055] According to a preferred specific embodiment of the present invention, the magnet is configured to have at least six additional magnetic field regions and / or quadrupole fields in the secondary particle optical beam path after passing through the first magnetic field region. When the energy of the secondary particles changes and their paths form the second particle optical beam path, the at least six additional magnetic field regions and / or quadrupole fields are arranged to precisely couple the particle optical axis in the secondary beam path into the downstream projection optical unit in terms of offset and angle, and additionally enable near-axis astigmatism-free, near-axis distortion-free and near-axis dispersion-free imaging.

[0056] According to another preferred embodiment, at least one of the additional magnetic field regions of the secondary particle optical beam path is arranged in a gap between the first magnetic field region and the second magnetic field region of the primary particle optical beam path.

[0057] According to another preferred embodiment, the magnet configuration further comprises a magnetic shielding wall, which is configured between at least one of the magnetic field regions of the primary particle optical beam path and at least one of the magnetic field regions of the secondary particle optical beam path. Of course, it can also be substantially continuously configured between all magnetic field regions of the primary particle optical beam path and all magnetic field regions of the secondary particle optical beam path. For example, the magnetic shielding wall comprises a mesh of soft magnetic material, which minimizes crosstalk between the magnetic field regions of the primary path and the secondary path.

[0058] According to another preferred embodiment, the magnetic shielding wall has an open channel, and when the magnet configuration is closed, the first particle optical beam path passes through the open channel in a straight line along the particle optical axis. As a result, when the magnetic field area of ​​the primary path is closed, the alignment optical axis characteristic of the magnet configuration can be used for adjustment purposes. The open channel can be characterized by a ratio K of the channel length L to the channel width B. For example, in the case of K≥3, preferably K≥5 or optimally K≥10, despite the presence of the open channel, the magnetic shielding between the magnetic field areas of the primary path and the secondary path can still be well ensured.

[0059] According to another preferred embodiment of the present invention, the particle optical configuration is a multi-beam particle microscope, and the particle optical configuration further has the following:

[0060] a multi-beam particle generator configured to generate a first field of a plurality of charged first individual particle beams;

[0061] a first particle optical unit having a primary particle optical beam path, arranged to image the generated first individual particle beam onto the object plane so that the first individual particle beam impinges on the object at an incident position forming a second field;

[0062] a detection unit having a plurality of detection areas forming a third field;

[0063] a second particle optical unit having a secondary particle optical beam path arranged to image a second individual particle beam emitted from an incident position in the second field onto a third field of detection area of ​​the detection system;

[0064] a magnetic and / or electrostatic objective lens through which both the first individual particle beam and the second individual particle beam pass; and

[0065] a controller arranged to control particle optical components and / or components of the magnet arrangement in the primary and / or secondary particle optical beam paths,

[0066] Wherein the magnet arrangement is arranged in a first particle optical beam path between the multi-beam particle generator and the objective lens, and wherein the magnet arrangement is arranged in a second particle optical beam path between the objective lens and the detection unit.

[0067] The first individual charged particle beam can be, for example, an electron, a positron, a muon or an ion or other charged particle. If the number of the first individual particle beam is 3n(n-1)+1, this is advantageous, where n is any natural number. Then, the first individual particle beam can be configured in a hexagonal field. However, other configurations of the first individual particle beam are also possible. The second individual particle beam can be backscattered electrons or secondary electrons. In this case, for analysis, it is preferred that low-energy secondary electrons are used for image generation. However, mirror ions / mirror electrons can also be used as the second individual particle beam, that is to say, the first individual particle beam directly experiences inversion upstream of the object or at the object.

[0068] Of course, as already described above, the magnet configuration of the multi-beam particle microscope can still be extended or improved for the secondary particle optical beam path. According to a preferred specific embodiment of the present invention, the magnet configuration has at least one additional magnetic field region in the secondary particle optical beam path. For example, one or two or three additional magnetic field regions can be configured in the secondary particle optical beam path, as described in the prior art in EP 1 668 662B1. As a result, imaging aberrations caused by the magnet configuration or beam splitter can also be corrected in the secondary particle optical beam path.

[0069] According to a preferred embodiment of the present invention, the first individual particle beam imaging substantially exhibits no field tilt in the object plane. Of course, other imaging aberrations can also be corrected by means of appropriate design of the magnet configuration, as described in detail above.

[0070] According to a preferred embodiment of the present invention, the first individual particle beam is imaged into the object plane substantially without distortion as a whole, and / or

[0071] The first individual particle beam is imaged into the object plane substantially without dispersion, and / or

[0072] The incident position of the first individual particle beam in the object plane is astigmatic and circular. In addition, or as a replacement, other aberrations within the particle optical imaging range can also be corrected. Depend on the design, in order to correct, magnet configuration according to the present invention provides suitable manipulation parameters. Correction can also include the skew of the correction sample and / or the correction of the focus tilt caused by the misalignment of the illumination system / condenser lens system.

[0073] According to a preferred embodiment of the present invention, the first individual particle beam is imaged into the object plane without field astigmatism.

[0074] According to a preferred embodiment of the invention, the sum of all other second-order and third-order aberrations in the object plane does not exceed only 1 nm, in particular does not exceed only 0.5 nm or does not exceed only 0.25 nm.

[0075] The above-mentioned specific embodiments can be combined with each other in whole or in part as long as no technical contradiction occurs. BRIEF DESCRIPTION OF THE DRAWINGS

[0076] The present invention will be better understood with reference to the accompanying drawings, in which:

[0077] Figure 1 A multi-beam particle microscope is schematically shown;

[0078] Figure 2 Schematically illustrates a multi-beam particle microscope with a beam splitter or magnet configuration according to the prior art;

[0079] Figure 3 schematically illustrates a magnet configuration according to the prior art and the occurrence of a field tilt;

[0080] Figure 4 schematically illustrates the manipulation parameters in the case of a magnet configuration with two magnetic field regions in the primary path;

[0081] Figure 5 schematically illustrates the manipulation parameters in the case of a magnet configuration with three magnetic field regions in the primary path;

[0082] Figure 6 Schematically illustrating the steering parameters in the case of a symmetrical magnet configuration with three magnetic field regions in the primary path;

[0083] Figure 7 schematically illustrates the steering parameters for a symmetrical magnet configuration with four magnetic field regions in the primary path; and

[0084] Figure 8 The configuration or alignment of a first magnetic field region in the particle optical beam path is schematically depicted. DETAILED DESCRIPTION

[0085] Figure 1 A multi-beam particle microscope 1 is schematically shown. The multi-beam particle microscope 1 includes a beam generating device 300 having a particle source 301 (e.g., an electron source). A divergent particle beam 309 is collimated by a sequence of condenser lenses 303.1 and 303.2 and is incident on a multi-hole configuration 305. The multi-hole configuration 305 includes a plurality of multi-hole plates 306 and a field lens 308. A single or multiple individual particle beams 3 are generated by the multi-hole configuration. The midpoints of the holes in the multi-hole plate configuration are configured in a field, which is imaged onto another field formed by the beam spot 5 in the object plane 101. The pitch between the midpoints of the holes of the multi-hole plate 306 can be, for example, 5 μm, 100 μm, and 200 μm. The diameter D of the hole is smaller than the pitch of the midpoints of the hole, and examples of the diameter are 0.2 times, 0.4 times, and 0.8 times the pitch between the midpoints of the hole.

[0086] The multi-aperture arrangement 305 and the field lens 307 are arranged to generate a plurality of focal points 323 of the primary particle beam 3 in a raster arrangement on a surface 325. The surface 325 need not be a flat surface but may be a spherically curved surface to take into account the field curvature of the subsequent particle optics.

[0087] The multi-beam particle microscope 1 also includes a system of an electromagnetic lens 103 and an objective lens 102, which images the beam focus 323 from the intermediate image plane 325 into the object plane 101 in a reduced size manner. In the meantime, the first individual particle beam 3 passes through the beam splitter 400 and the collective beam deflection system 500, thereby causing the plurality of first individual particle beams 3 to be deflected and scan the image field during operation. For example, the first individual particle beam 3 incident on the object plane 101 forms a substantially regular field, wherein the pitch between adjacent incident positions 5 can be, for example, 1 μm, 10 μm or 40 μm. For example, the field formed by the incident positions 5 can have a rectangular or hexagonal symmetry.

[0088] The object 7 to be inspected can be of any desired type, such as a semiconductor wafer or a biological sample, and can include a configuration of miniaturized components, etc. The surface 15 of the object 7 is arranged in the object plane 101 of the objective lens 102. The objective lens 102 can include more than one electron-optical lens. This can be, for example, a magnetic objective lens and / or an electrostatic objective lens.

[0089] The primary particle beam 3 incident on the object 7 produces interaction products, such as secondary electrons, backscattered electrons, or primary particles that undergo motion reversal for other reasons, which are emitted from the surface of the object 7 or from the first plane 101 or the object plane 101. The interaction products emitted from the surface 15 of the object 7 are shaped by the objective lens 102 to form a secondary particle beam 9. In this process, the secondary particle beam 9 passes through the beam splitter 400 after passing through the objective lens 102 and is provided to the projection system 200. The projection system 200 includes an imaging system 205 having a first lens 210 and a second lens 220, a contrast aperture 222, and a multi-particle detector 209. The incident positions of the second individual particle beam 9 on the detection area of ​​the multi-particle detector 209 are located in a third field having a regular pitch with each other. Exemplary values ​​are 10μm, 100μm, and 200μm.

[0090] The multi-beam particle microscope 1 also has a computer system or control unit 10, which can in turn be made of one part or multiple parts and is designed to control the individual particle optical components of the multi-beam particle microscope 1 and to evaluate and analyze the signals obtained by the multi-particle detector 209 or detection unit 209.

[0091] Further information about such multi-beam particle beam systems or multi-beam particle microscopes 1 and the components used therein, such as particle sources, multi-aperture plates and lenses, can be obtained from international patent applications WO 2005 / 024881A2, WO 2007 / 028595A2, WO 2007 / 028596 A1, WO 2011 / 124352A1 and WO 2007 / 060017 A2 and from German patent applications DE 102013 016 113 A1 and DE 10 2013 014 976A1, the full scope of their disclosure contents being incorporated into the present application by reference.

[0092] Figure 1 The beam splitter 400 or the magnet arrangement 400 is depicted only schematically in the figure without further details. In principle, the magnet arrangement 400 can be a magnet arrangement 400 comprised in a particle-optical arrangement according to the invention. However, a beam splitter 400 known from the prior art or from EP 1 668 662 B1 can also be used in conjunction with the particle-optical arrangement according to the invention. Figure 1 The multi-beam particle microscope 1 is compatible.

[0093] Figure 2 Schematically, a cross-section of a multi-beam particle microscope 1 with a beam splitter 400 or a magnet arrangement 400 according to the prior art is shown. Special aspects of the known beam splitter 400 are explained here. Figure 2In the depicted multi-beam particle microscope 1, the particle beam emitted by the particle source 301 passes through the magneto-optical focusing lens system 303 and then enters the multi-aperture arrangement 305. The latter acts as a multi-beam particle generator, and the individual particle beams 3 emitted from the multi-aperture arrangement 305 immediately pass through the magneto-optical field lens system 307 and then enter the magneto-optical beam splitter 400 or magnet arrangement 400. The depicted beam splitter 400 includes a beam tube arrangement 490, which has a Y-shaped embodiment and includes three limbs 461, 462 and 463 in the example shown. Here, in addition to two flat, interconnected structures for holding the magnetic sectors or magnetic field regions 410, 430, the beam splitter 400 also includes two magnetic sectors or magnetic field regions 410 and 430 contained in or fixed to the structures. In the case of a semiconductor wafer with an HV structure, after passing through the beam splitter 400, the first particle beam 3 passes through the scanning deflector 500 and immediately passes through the particle optical objective 102 before the primary particle beam 3 is incident on the surface 15 of the object 7. In this case, the HV structure represents the main horizontal or vertical profile of the semiconductor structure. In this case, the semiconductor wafer 7 is positioned by a displacement stage 600 below the objective 102. Due to the incidence of the first individual particle beam 3, secondary particles or the second individual particle beam 9 are emitted from the object 7. After emerging from the object 7, the second individual particle beam 9 first passes through the particle optical objective 102, then through the scanning deflector 500, and then through the beam splitter 400. From the beam splitter 400, the second individual particle beam 9 emerges from the limb 462, passes through the projection lens system 205 (drawn in a very simplified manner), passes through the electrostatic element 260, the so-called anti-scan, and then irradiates the particle optical detection unit 209. For simplicity, the control unit 209 used to control the particle optical detection unit 209 according to the present invention is shown in FIG. Figure 2 The computer system 10 or control unit 10 of the particle optical components and other components of the multi-beam particle microscope 1 is not Figure 2 Depicted in.

[0094] It can be clearly seen from the beam splitter 400 according to the prior art that for the illustrated configuration and the necessary clearing of the surroundings of the first particle optical beam path 13 and the second particle optical beam path 11, it is advantageous to provide a beam pipe arrangement 490 within the beam splitter 400. However, it is also obvious that when the beam splitter 400 is in the closed state, the first particle optical beam path 13 cannot pass through the beam splitter 400 but is incident on the walls of the beam pipe arrangement 490. This makes adjustment of the multi-beam particle microscope 1 more difficult, since the influence of the beam splitter 400 on a possible misadjustment cannot be checked separately.

[0095] Figure 3The magnet configuration according to the prior art and the occurrence of field tilt are schematically shown. In the example shown, the magnet configuration 400 includes a first magnetic field region 410 and a second magnetic field region 430, the directions of the magnetic fields of which are opposite to each other, and the primary particle optical beam path 13 travels through these two magnetic field regions. In addition, three additional magnetic field regions 450, 460 and 470 are provided in the example shown. The secondary particle optical beam path 11 extends through the first magnetic field region 410 and through these additional magnetic field regions 450, 460 and 470. The magnetic field in the magnetic field region 450 is oriented the same as the magnetic field in the magnetic field region 410, so the curvature of the second particle optical beam path 11 has no curvature change in these magnetic field regions 410, 450.

[0096] Figure 3 The beam splitter shown is not of the optical axis alignment type: on the contrary, there is a skew angle β between the optical axis of the first particle optical beam path 13 and the axis A, which corresponds to the optical axis of the objective lens 102 or its continuation. The lower edge of the first magnetic field region 410 is set at a right angle to the axis A, which overall facilitates the characteristics of imaging into the object plane 101. When manufacturing the multi-beam particle microscope 1, the skew angle β requires specific and precise measurement, which is quite time-consuming and costly compared to the case of the optical axis alignment type or Cartesian configuration, in which the skew angle β is zero.

[0097] The angle γ is the so-called splitting angle, which provides a measure of the separation of the primary particle optical beam path 13 from the secondary particle optical beam path 11 within the magnetic field region 410. This angle must not be chosen too small, otherwise there may not be enough installation space available to configure the magnetic field regions 450, 460 and 470 in the secondary particle optical beam path 11.

[0098] The imaging aberrations of the first particle optical beam path 13 can be largely corrected and the imaging can be virtually free of astigmatism to the first order and virtually free of distortion to the first order. However, within the scope of more precise measurement tasks, the resolution requirements on the multibeam particle microscope 1 are becoming increasingly higher, and it has been shown that Figure 3 The field tilt of the beam splitter 400 is depicted Usually constitutes most of the remaining residual aberrations. Figure 3 In this field, the tilt Not drawn to scale. The first individual particle beams 3 illuminate the object or the object plane 101 at slightly different heights, wherein the position of the smallest particle beam diameter in this case is regarded as the focus. An individual particle beam 3 lying exactly on the optical axis A has a focus position lying exactly on the object plane 101, a first individual particle beam 3 arranged to the left of the optical axis A has a focus position arranged directly in front of the object plane 101, and a first individual particle beam 3 arranged to the right of the optical axis A has a focus position slightly below the object plane 101. Field tilt The focusing can be substantially explained by slightly different path lengths travelled by the plurality of first individual particle beams 3 within the magnet arrangement 400. According to the inventors' tests, due to the previous design with two magnetic field regions 410 and 430 and the provided tilt angle β, the field tilt cannot be compensated.

[0099] Figure 4 Schematically shows the manipulation parameters in the case of a magnet configuration 400 with two magnetic field regions 410 and 430 in the primary path 13 according to the prior art; the secondary path is not in Figure 4 . In order to obtain a vertical exit of the primary particle optical beam path 13 from the first magnetic field region 410, and good imaging properties at the objective lens (not shown), the inclination of the exit point P1 and the exit region G1 is fixed in the design of the magnetic field configuration 400, the angle α1 is 90°, and the position in the Z-axis direction is defined as z1. Therefore, the remaining entrance and exit regions entering / leaving the magnetic field regions 410, 430 can be used for the adaptation of the particle optical properties. For example, points P2, P3 and P4 can be described by their z positions z2, z3, z4 and angles α2, α3 and α4; however, other coordinates can certainly be selected to achieve this purpose. In principle, the corresponding arc lengths S2 and S1 in the magnetic field regions 430 and 410 are adapted by the appropriate selection or definition of points P2, P3 and P4. The drift path 405 is configured between points P2 and P3, and the length of the drift path is generated by the definition of points P2 and P3.

[0100] If point P1 is kept fixed, and the inclination G1 and magnetic field strength in magnetic field regions 410 and 430 are defined, then Figure 4 The system shown has up to six independent manipulation parameters: z positions z2, z3, and z4 and angles α2, α3, and α4. These six manipulation parameters can be used to optimize the imaging characteristics of the magnet configuration 400 and reduce aberrations. Figure 4 Under certain incident radiation conditions (if any) of the configuration shown, it is possible to fully compensate for the path differences in addition to the already corrected aberrations, and thus substantially eliminate the field tilt.

[0101] Figure 5 The manipulation parameters are schematically shown for a magnet configuration 400 with three magnetic field regions 410, 420 and 430 in the primary path 13. Figure 5 The secondary path 11 is shown in FIG; however, it may correspond to Figure 3 The configuration shown in FIG. 4 has magnetic field regions 450, 460, and 470. Other designs are also possible.

[0102] Figure 5The magnet configuration 400 in FIG. 4 is of the optical axis alignment type: the entry direction of the primary particle optical beam path 13 into the third magnetic field region 430 and the exit direction of the primary particle optical beam path 13 from the first magnetic field region 410 are parallel to each other and not offset. The directions correspond to the optical axis A, and the direction of the optical axis A corresponds to the optical axis of the objective lens 102 (not shown here). The orientation of the primary particle optical beam path 13 when it exits the first magnetic field region 410 is determined by Figure 5 , which is defined and represented by the angle α1 (which is 90°) in . In other words, the departure inclination of the first magnetic field region 410 is 0°; the exit region G1 (the letter G stands for "trench") is orthogonal to the z-axis, and its orientation is parallel to the optical axis A. In addition, the magnet configuration 400 specifies that the magnetic field of the first magnetic field region 410 and the magnetic field of the third magnetic field region 430 deflect the primary particle optical beam path 13 in substantially the same direction (in this case: into the plane of the drawing). In this case, the direction of the magnetic field is orthogonal to the z-axis and is also orthogonal to the optical axis A of the objective lens 102 (not shown here). In contrast, the magnetic field in the second magnetic field region 420 is oriented in opposite directions, with the result that the first magnetic field region 410 and the second magnetic field region 420 deflect the primary particle optical beam path 13 in substantially different directions.

[0103] In order to change or define the particle optical imaging properties of the magnet configuration 400, the magnet configuration 400 having a fixed point P1 (position and orientation) now includes ten parameters that can be adjusted independently of each other, specifically the angles α2, α3, α4, α5 and α6 representing the inclinations of the grooves G2, G3, G4, G5 and G6, and the z positions z2, z3, z4, z5 and z6. Figure 5 The absolute inclination angles are plotted; however, it is of course also possible to define the angular differences of the grooves G1 to G6 relative to the horizontal configuration of the grooves as a measure of the inclination. Furthermore, the individual angles α1 to α6 are selected relative to the field-free region (in this case the drift paths 405 and 406 or the region outside the magnet configuration 400), since here the angles can be plotted directly. However, these definitions can also be defined differently.

[0104] If it not only leaves point P1 but also enters point P6, and is therefore Figure 5 If the entire range of the magnet configuration 400 in the z direction is defined in the configuration of , the number of manipulation parameters is reduced accordingly. If the tilt α6 is also defined, there are still eight manipulation parameters.

[0105] In order to eliminate the field tilt caused by the beam splitter, according to Figure 5 The magnet configuration 400 can be configured such that substantially no path difference occurs when the plurality of first individual particle beams 3 pass through the magnet configuration 400 .

[0106] Figure 6A magnet arrangement 400 is shown with a symmetry plane Sy, about which the primary particle optical beam path 13 or the beam path of the chief ray is mirror-symmetric when passing through the magnet arrangement 400. The magnet arrangement 400 comprises three magnetic field regions 410, 420 and 430 in the primary path 13 and is symmetrical. Figure 6 The secondary path 11 is shown in FIG. However, the secondary path 11 may be designed as has been described above in the context of other exemplary embodiments.

[0107] The symmetry plane Sy intersects the second magnetic field region 420, to be precise in the middle. In the case of a symmetrical magnet configuration 400, the angles α1 and α6 are equal and are 90° in the example shown. Thus, the departure inclination of the first magnetic field region 410 is 0° relative to the horizontal; the same applies to the entry inclination of the third magnetic field region 430. The angles α2 and α5 as well as α3 and α4 correspond to each other. The z positions z1 and z6 are at the same distance from the symmetry plane Sy; the same applies to the pair z2 and z5 as well as the pair z3 and z4. As a result of the defined symmetry, the magnet configuration 400 still includes a total of six manipulation parameters, which can be defined independently of each other. These parameters are related to Figure 4 Due to the more pronounced symmetry of the magnet configuration 400, aberrations can be reduced or completely compensated. For this purpose, it is necessary to place further demands on the symmetry of the primary particle optical beam path 13, for example, symmetry related to divergence. Each first individual particle beam 3 may need to be emitted with a divergence D i Entering magnet configuration 400, and with the same divergence (although with opposite sign, i.e. -D i ) leaves magnet configuration 400.

[0108] In the example shown, sectors 410 and 430 are set to have the same magnetic field strength, which helps symmetry. The magnetic field strength of the second magnetic field region 420 in the opposite direction can also be selected to be the same in absolute value.

[0109] The particle optical configuration also has a deflection configuration ( Figure 6430 ), which is configured upstream of the third magnetic field region 430 in the direction of the primary particle optical beam path 13, and is configured to set the entry direction of the primary particle optical beam path 13 into the third magnetic field region 430, and thus set the required entry tilt, with an accuracy of + / -0.1° or better, in particular + / -0.05° or better, or + / -0.025° or better, and is configured to set the entry position of the primary particle optical beam path 13 into the third magnetic field region 430, with an accuracy of + / -0.3mm or better, in particular + / -0.1mm or better or even + / -0.05mm or better. For example, the deflection configuration includes two adjustment deflectors, which can be adjusted accurately and independently of each other, so that both the offset and the deflection of the first individual particle beam 3 when entering the magnet configuration 400 can be set accurately and independently of each other. This prevents possible recurrence of beamsplitter aberrations which have in fact been corrected by means of the design of the magnet arrangement 400, such as field tilt in the case of skewed or offset beam incoupling, field astigmatism, global astigmatism or other second or third order aberrations.

[0110] Figure 7Another symmetrical magnet configuration 400 having exactly four magnetic field regions 410, 420, 440 and 430 in the primary path is schematically shown. Since a total of four magnetic field regions 410, 420, 440 and 430 are used in the primary particle optical beam path 13, more manipulation parameters are provided. However, due to the symmetry, the manipulation parameters are lost again. This magnet configuration 400 is also of the optical axis alignment type. As with positions z1 and z8 or points P1 and P8, angles α1 and α8 are defined. The absolute values ​​of angles α2 and α7, α3 and α6, α4 and α5 are equal. The symmetry plane Sy is configured between the second magnetic field region 420 and the fourth magnetic field region 440. Points P4 and P5 are at the same distance from the symmetry plane Sy; this also applies to points P3 and P6 and P2 and P7, and also to points P1 and P8 or their respective z coordinates. In this defined case, there are three manipulation parameters from the angles α2, α3 and α4 and three manipulation parameters from the z positions z2, z3 and z4, taking into account the required symmetry conditions. In contrast, if the entry positions P1 and P8 are not defined simultaneously, but for example only the exit position P1 is defined, an additional manipulation parameter for the z position can be obtained. This causes the position displacement of the symmetry plane Sy, or in principle, the distance between the z positions z4 and z5 to change. Of course, even more symmetries can be eliminated and released here, and in theory, up to 16 manipulation parameters can be obtained due to the four parts of the magnet configuration 400 in the primary path. The introduction of symmetry reduces the number of these manipulation parameters, but can compensate for aberrations. In addition, due to the symmetrical design of the magnet configuration 400, five second-order aberration terms are eliminated (a total of 18 linearly independent second-order aberration terms). In particular, the field tilt caused by the magnet configuration 400 can be compensated or not appear at all.

[0111] exist Figure 6 and Figure 7 In the case of the depicted symmetrical magnet configuration 400, the sum of the signed absolute value of the magnetic field intensity multiplied by the associated arc length in the magnetic field regions 410, 420, 440, 430 along which the primary particle optical beam path 13 travels in the magnetic field regions 410, 420, 440, and 430 is substantially zero for all magnetic field regions 410, 420, 440, and 430. The magnetic field is uniform and usually has no sign; however, this sign is used mathematically to define the direction of the magnetic field. In other words, in the sense of a vector product, the sign specifies the direction of the magnetic field relative to a preferred axis perpendicular to the deflection plane. Specifically, in Figure 6In the illustrated embodiment, for the central beam, the sum of the following products is zero: M430*S3+M420*S2+M410*S1=0. In addition, the lengths of the drift paths 406 and 405 are the same. Overall, this therefore results in a condition for the alignment of the optical axis characteristics of the magnet configuration 400. The above conditions do not have to apply in this way to the off-axis, divergent first individual particle beam 3.

[0112] for Figure 7 In the illustrated exemplary embodiment, to satisfy the alignment condition, the sum of the following products is zero:

[0113] M430*S4+M440*S3+M420*S2+M410*S1. Furthermore, the drift paths 405 and 407 have the same length. The drift path 406 extends parallel to the z-axis or optical axis A (extension of the objective optical axis). In principle, the length of the drift path 406 can be freely selected; it can serve as a further manipulated parameter of the target variable to be set.

[0114] During operation of the particle optical configuration, the following relationship advantageously applies to the splitting angle γ, at which the primary particle optical beam path 13 is deflected as a whole in the first magnetic field region 410: γ ≥ 2°, preferably γ ≥ 5°, and most preferably γ ≥ 10°.

[0115] In addition, more advantageously, the overall length of the magnet configuration 400, defined by the distance between the entry point (P6, P8) where the primary particle optical beam path 13 enters the third magnetic field region 430 and the exit point P1 where the primary particle optical beam path 13 leaves the first magnetic field region 410, is less than or equal to 1.0 m, preferably less than or equal to 0.5 m or most preferably less than or equal to 0.3 m.

[0116] Furthermore, it is advantageous if the magnet arrangement 400 according to the invention does not comprise a beam tube arrangement in which the primary particle optical beam path 13 extends within the magnet arrangement 400. Alternatively, the magnet arrangement 400 can have a vacuum chamber in which the primary particle optical beam path extends within the magnet arrangement 400. Thus, even if the magnet arrangement 400 is switched off, it can be ensured that the first individual particle beam 3 passes through the magnet arrangement 400 or emerges from the magnet arrangement 400 at a departure point P1 which is the same as the departure point P1 when the magnet arrangement 400 is switched on. This facilitates the adjustment of the multi-beam particle microscope 1 and is a significant advantage of the optical axis alignment design of the magnet arrangement 400.

[0117] However, according to an alternative exemplary embodiment, the magnet arrangement 400 has a beam pipe arrangement (not shown here) within which the primary particle optical beam path 13 extends within the magnet arrangement 400, wherein the beam pipe arrangement has a torus topological form. As a result, the optical axis alignment property of the magnet arrangement 400 can be used for adjustment purposes when the primary path beam splitter is closed or when the magnetic field regions 410, 420, 430, 440 in the primary particle optical beam path 13 are closed. The torus topology very generally describes two branches of a beam pipe arrangement, wherein the primary particle optical beam path 13 can branch at a first branch and can be coupled back at a second branch when the magnetic field regions 410, 420, 430, 440 are closed.

[0118] According to a preferred embodiment of the invention, during operation of the particle optical arrangement, the following relationship applies to the filling factor F of the beam tube arrangement: F≤50%, preferably F≤30%, or optimally F≤10%. In this case, the filling factor is given as the ratio of the maximum diameter S of the beam (the sum of the individual particle beams at a time) to the inner diameter R of the beam tube or beam tube arrangement. In this case, the beam tube is made of non-magnetic material. For a given maximum diameter S of the beam, the inner diameter R of the beam tube can be determined accordingly. This minimizes the contamination of the beam tube due to interaction with the charged particle beam 3, 9 during operation, in order to avoid undesired beam deflections caused by charged contamination points on the inside of the beam tube.

[0119] Figure 8 The configuration or alignment of the first magnetic field region 410 in the particle optical beam path is schematically depicted. As in the previous exemplary embodiment, the departure inclination of the exit region or groove G1 from the first magnetic field region 410 is also 0°. Therefore, there is a right angle between the exit region or groove G1 and the axis A. If the particle optical device is configured in a multi-beam particle microscope 1, the departure direction from the first magnetic field region 410 corresponds in particular to the particle optical axis direction of the objective lens 102. During operation of the particle optical configuration, the secondary particle beam 9 (e.g., an electron beam) traveling through the secondary particle beam path 11 typically has a lower kinetic energy than the primary particle beam 3. Therefore, the secondary particles 9 are slower and more strongly deflected in the first magnetic field region 410, or the trajectory radius r of the trajectory described thereby in the uniform magnetic field. Bis smaller than the corresponding trajectory radius of the faster primary particle 3 or electron. Therefore, even when the groove G2 is orthogonally aligned with respect to the axis A, the departure angle σ of the secondary particle optical beam path 11 is, in principle, different from the entry angle Φ of the primary beam 3 of the primary particle optical beam path 13. The entry angle Φ and the departure angle σ can be defined by the entry inclination of the first magnetic field region 410 or the groove G2. In the process, it is advantageous to limit the departure angle σ of the secondary particle optical beam path 11 from the first magnetic field region 410 to σ≤35°, preferably σ≤25° or σ≤15°. This avoids large aberration aggregation when emitting from the first magnetic field region 410, and creates additional installation space for possible additional secondary path magnetic field regions in the gap between the first magnetic field region 410 and the second magnetic field region 420. According to another exemplary embodiment, at least one of the additional magnetic field regions of the secondary particle optical beam path 11 is configured in the gap between the first magnetic field region 410 and the second magnetic field region 420 of the primary particle optical beam path 13.

[0120] For example, the magnet configuration 400 can have at least two additional magnetic field regions in the secondary particle optical beam path 11 after passing through the first magnetic field region 410, and in the case where the energy of the secondary particles changes and their paths form the second particle optical beam path 11, the at least two additional magnetic field regions are configured to accurately couple the particle optical axis Z in the secondary beam path 11 into the downstream projection system 200 in terms of offset and angle (see Figure 1 Example). For example, the varying energy of the secondary particle beam 9 may be the result of modifying the impact energy setting.

[0121] According to an exemplary embodiment of the present invention, the magnet configuration 400 has at least six additional magnetic field regions and / or quadrupole fields in the secondary particle optical beam path 11 after passing through the first magnetic field region 410. In the case where the energy of the secondary particles 9 changes and their paths form the second particle optical beam path 11, the at least six additional magnetic field regions and / or quadrupole fields are arranged to accurately couple the particle optical axis Z in the secondary beam path 11 into the downstream projection optical unit 200 in terms of offset and angle (see Figure 1 example), and additionally enables paraxial astigmatism-free, paraxial distortion-free, and paraxial dispersion-free imaging.

[0122] According to another exemplary embodiment, the magnet configuration 400 further has a magnetic shielding wall, which is configured between at least one of the magnetic field regions 410, 420, 430, 440 of the primary particle optical beam path 13 and at least one of the magnetic field regions of the secondary particle optical beam path 11. Of course, it can also be substantially continuously configured between all the magnetic field regions 410, 420, 430, 440 of the primary particle optical beam path 13 and all the magnetic field regions of the secondary particle optical beam path 11. For example, the magnetic shielding wall includes a soft magnetic material mesh that minimizes crosstalk between the primary path and secondary path magnetic field regions.

[0123] According to another exemplary embodiment, the magnetic shielding wall has an open channel, and when the magnet configuration is closed, the first particle optical beam path passes through the open channel in a straight line along the particle optical axis. As a result, when the magnetic field area of ​​the primary path is closed, the alignment optical axis characteristic of the magnet configuration can be used for adjustment purposes. The open channel can be characterized by a ratio K of the channel length L to the channel width B. For example, in the case of K≥3, preferably K≥5 or K≥10, despite the presence of the open channel, the magnetic shielding between the magnetic field areas of the primary path and the secondary path can still be well ensured.

[0124] The magnet arrangement 400 according to the present invention can also be integrated into a multi-beam particle microscope 1, for example Figure 1 In the microscope schematically depicted in FIG. 4 , a magnet arrangement 400 is used, just as in the prior art.

[0125] According to an exemplary embodiment, multiple first individual particle beams 3 are imaged in the object plane 101 without substantially showing field tilt. Of course, other imaging aberrations can also be corrected by means of the appropriate design of the magnet configuration 400, as described in detail above. According to an exemplary embodiment, multiple first individual particle beams 3 are imaged in the object plane 101 substantially without distortion as a whole, and / or the first individual particle beam 3 is imaged in the object plane 101 substantially without dispersion, and / or the incident position 5 of the first individual particle beam 3 in the object plane 101 is astigmatic and circular. In addition, or as an alternative, other aberrations within the particle optical imaging range can also be corrected. Depending on the design, in order to correct, the magnet configuration 400 according to the present invention provides appropriate manipulation parameters. Correction can also include correction of the skew of the sample and / or correction of the focus tilt caused by the misalignment of the illumination system / condenser lens system.

[0126] According to an exemplary embodiment, the first individual particle beam 3 is imaged into the object plane 101 without field astigmatism. Additionally, it is applicable that the sum of all other second-order and third-order aberrations in the object plane 101 does not exceed only 1 nm, preferably does not exceed only 0.5 nm or does not exceed only 0.25 nm.

[0127] Other exemplary embodiments are listed below:

[0128] Example 1. A particle optical configuration for providing a primary particle optical beam path for a plurality of first individual particle beams, the first individual particle beams emanating from a multi-beam particle generator and directed toward an object positionable in an object plane of the particle optical configuration, and for providing a secondary particle optical beam path for a plurality of second individual particle beams emanating from the object,

[0129] Wherein the particle optical configuration has a magnet configuration, the magnet configuration comprising:

[0130] a first magnetic field region through which the primary particle optical beam path and the secondary particle optical beam path pass, for separating the primary particle optical beam path and the secondary particle optical beam path from each other;

[0131] a second magnetic field region, disposed in the primary particle optical beam path and not disposed in the secondary particle optical beam path, the second magnetic field region being disposed upstream of the first magnetic field region relative to the primary particle optical beam path, and the first magnetic field region and the second magnetic field region substantially deflect the primary particle optical beam path in different directions;

[0132] a third magnetic field region, disposed in the primary particle optical beam path and not disposed in the secondary particle optical beam path, the third magnetic field region being disposed upstream of the second magnetic field region relative to the primary particle optical beam path, and the first and third magnetic field regions substantially deflecting the primary particle optical beam path in the same direction,

[0133] An entry direction of the primary particle optical beam path into the third magnetic field region and an exit direction of the primary particle optical beam path from the first magnetic field region are substantially parallel to each other and substantially not offset.

[0134] Example 2. A particle optical configuration as described in the previous example,

[0135] wherein a first drift region substantially free of a magnetic field is arranged in the primary particle optical beam path between the first magnetic field region and the second magnetic field region; and / or

[0136] A second drift region substantially free of magnetic field is arranged in the primary particle optical beam path between the second magnetic field region and the third magnetic field region.

[0137] Example 3. The particle optical configuration as described in Example 1,

[0138] wherein the magnet configuration has a fourth magnetic field region that is configured in the primary particle optical beam path and not configured in the secondary particle optical beam path,

[0139] wherein the fourth magnetic field region is arranged upstream of the second magnetic field region and downstream of the third magnetic field region relative to the primary particle optical beam path, and

[0140] The fourth magnetic field region and the second magnetic field region substantially deflect the primary particle optical beam path in the same direction.

[0141] Example 4. A particle optical configuration as described in the previous example,

[0142] wherein a first drift region substantially free of a magnetic field is arranged in the primary particle optical beam path between the first magnetic field region and the second magnetic field region; and / or

[0143] wherein a second drift region substantially free of a magnetic field is arranged in the primary particle optical beam path between the second magnetic field region and the fourth magnetic field region; and / or

[0144] A third drift region substantially free of magnetic field is arranged in the primary particle optical beam path between the fourth magnetic field region and the third magnetic field region.

[0145] Example 5. A particle optical configuration as described in any of the preceding examples,

[0146] The magnet arrangement has no further magnetic field region in the primary particle optical beam path which is designed to deflect the primary particle optical beam path by more than 2°, in particular 1° or 0.5°.

[0147] Example 6. A particle optical configuration as described in any of the preceding examples,

[0148] The magnet arrangement is configured so that no substantial path difference occurs for the first plurality of individual particle beams when the first plurality of individual particle beams pass through the magnet arrangement.

[0149] Example 7. A particle optical configuration as described in any of the preceding examples,

[0150] Wherein the magnet configuration has a symmetry plane, when passing through the magnet configuration, the primary particle optical beam path is mirror-symmetric relative to the symmetry plane.

[0151] Example 8. The particle optical configuration as described in Examples 3 and 7,

[0152] The symmetry plane intersects with the second magnetic field region.

[0153] Example 9. The particle optical configuration as described in Examples 5 and 7,

[0154] The symmetry plane is configured between the second magnetic field region and the fourth magnetic field region.

[0155] Example 10. A particle optical configuration as described in any of the preceding examples,

[0156] wherein, during operation of the particle optical configuration, the direction of the magnetic field in all of the magnetic field regions of the magnet configuration is substantially orthogonal to the optical axis of the primary particle optical beam path, and wherein the magnetic field is substantially uniform.

[0157] Example 11. A particle optical configuration as described in the preceding example,

[0158] wherein, during operation of the particle optical arrangement, the magnetic fields uniform in the magnetic field regions in the primary particle optical beam path each have an absolute value of the magnetic field strength, and wherein the magnetic fields are each assigned a sign characterizing the direction of the magnetic field, and

[0159] wherein the product of the signed absolute value of the magnetic field strength and the associated arc length in the magnetic field region along which the primary particle optical beam path travels in the magnetic field region is substantially zero when summed up for all said magnetic field regions.

[0160] Example 12. A particle optical configuration as described in any of the preceding examples,

[0161] Therein, during operation of the particle-optical configuration, the following relation applies to the splitting angle γ of the overall deflection of the primary particle optical beam path in the first magnetic field region: γ≥2°, in particular γ≥5° or γ≥10°.

[0162] Example 13. A particle optical configuration as described in any of the preceding examples,

[0163] The overall length of the magnet configuration is defined by the distance between the entry point of the primary particle optical beam path into the third magnetic field region and the exit point of the primary particle optical beam path from the first magnetic field region, and the overall length is less than or equal to 1.0m, in particular less than or equal to 0.5m or less than or equal to 0.3m.

[0164] Example 14. A particle optical configuration as described in any of the preceding examples,

[0165] wherein each magnetic field region has an entrance region entering the inclined primary particle optical beam path and an exit region exiting the inclined primary particle optical beam path,

[0166] wherein the entry tilt is defined as the angle at which the alignment of the entry region deviates from the normal to the optical axis of the primary particle optical beam path, and

[0167] wherein the exit tilt is defined as the angle at which the alignment of the exit region deviates from the normal to the optical axis of the primary particle optical beam path, and

[0168] The departure inclination of the first magnetic field region is 0°.

[0169] Example 15. A particle optical configuration as described in the preceding example,

[0170] The entry inclination of the third magnetic field region is 0°.

[0171] Example 16. A particle optical configuration as described in any of the preceding examples,

[0172] Wherein the magnet arrangement does not include a beam pipe arrangement in which the primary particle optical beam path extends within the magnet arrangement.

[0173] Example 17. A particle optical configuration as described in the preceding example,

[0174] Wherein the magnet comprises a vacuum chamber within which the primary particle optical beam path extends within the magnet arrangement.

[0175] Example 18. A particle optical configuration as described in any of the preceding examples,

[0176] wherein no intermediate images of the first plurality of individual particle beams are arranged in the primary particle optical beam path within the magnet arrangement; and / or

[0177] In this case, no intersection of a plurality of first individual particle beams with one another is formed in the optical beam path of the primary particles within the magnet arrangement.

[0178] Example 19. A particle optical configuration as described in any of the preceding examples,

[0179] Wherein the magnet is configured to have at least one additional magnetic field region in the secondary particle optical beam path.

[0180] Example 20. A particle optical configuration as described in any of the preceding examples,

[0181] wherein the particle optical configuration is a multi-beam particle microscope, and wherein the particle optical configuration further has the following:

[0182] a multi-beam particle generator configured to generate a first field of a plurality of charged first individual particle beams;

[0183] a first particle optical unit having the primary particle optical beam path, arranged to image the generated first individual particle beam onto the object plane such that the first individual particle beam irradiates the object at an incident position forming a second field;

[0184] a detection unit having a plurality of detection areas forming a third field;

[0185] a second particle optical unit having the secondary particle optical beam path, arranged to image a second individual particle beam emitted from the incident position in the second field onto the third field of the detection area of ​​the detection system;

[0186] a magnetic and / or electrostatic objective lens, through which both the first individual particle beam and the second individual particle beam pass; and

[0187] a controller arranged to control particle optical components in the primary particle optical beam path and / or the secondary particle optical beam path and / or components of the magnet arrangement,

[0188] Wherein the magnet configuration is configured in the primary particle optical beam path between the multi-beam particle generator and the objective lens, and wherein the magnet configuration is configured in the secondary particle optical beam path between the objective lens and the detection unit.

[0189] Example 21. A particle optical configuration as described in the preceding example,

[0190] The first individual particle beam is imaged on the object plane and exhibits substantially no field tilt.

[0191] Example 22. The particle optical configuration of any one of Examples 20 to 21,

[0192] wherein the first individual particle beam is imaged into the object plane substantially without distortion as a whole, and / or

[0193] wherein the first individual particle beam is imaged into the object plane substantially without dispersion, and / or

[0194] The incidence positions of the individual particle beams in the object plane are astigmatic and circular.

[0195] Reference numerals list

[0196] 1Multi-beam particle microscope

[0197] 3. Primary particle beam (individual particle beam)

[0198] 5Beam spot and incident position

[0199] 7 Objects and samples

[0200] 9 Secondary particle beam

[0201] 10Computer systems, controllers

[0202] 11 Secondary particle optical beam path

[0203] 13 Primary particle optical beam path

[0204] 15 Sample surface

[0205] 101 Object Plane

[0206] 102 Objective lens

[0207] 105 Axis

[0208] 200 Detector System

[0209] 205 Projection lens system

[0210] 209 detection system, multi-particle detector, detection unit

[0211] 210 Lens

[0212] 220 Lens

[0213] 222 Contrast stop

[0214] 260 Anti-scan

[0215] 300 Beam generation equipment

[0216] 301 Particle Source

[0217] 303 Condenser Lens System

[0218] 305 Multi-hole Configuration

[0219] 306 Micro-optics

[0220] 307 Field Lens

[0221] 308 Field Lens

[0222] 309 Divergent Particle Beam

[0223] 323 Beam Focus

[0224] 325 Intermediate Image Surface

[0225] 400 beam splitter, magnet configuration

[0226] 405 Drift Path

[0227] 406 Drift Path

[0228] 407 Drift Path

[0229] 410 Magnetic Field Region

[0230] 420 Magnetic Field Area

[0231] 430 Magnetic Field Area

[0232] 440 Magnetic Field Region

[0233] 450 Magnetic Field Area

[0234] 460 Magnetic Field Area

[0235] 461 Beam tube configuration limbs

[0236] 462 Beam tube configuration limbs

[0237] 463 Beam tube configuration limbs

[0238] 466 branch point

[0239] 470 Magnetic Field Area

[0240] 490 beam tube configuration

[0241] 500 Scanning Deflector

[0242] 600 Translation stage or positioning device

[0243] A-axis

[0244] z1-z8 z position

[0245] α1-α8 inclination angle

[0246] β Bevel

[0247] γ Splitting angle

[0248] δ Field tilt

[0249] σ Departure angle

[0250] Φ Entry Angle

[0251] G1-G8 magnetic field area edge, groove, depression

[0252] P1-P8 points / positions

[0253] S1-S4 arc length

[0254] Sy symmetry plane

Claims

1. A particle optical arrangement for providing a primary particle optical beam path for a plurality of first individual particle beams, the first individual particle beams emanating from a multi-beam particle generator and directed toward an object positionable in an object plane of the particle optical arrangement, and for providing a secondary particle optical beam path for a plurality of second individual particle beams, the second individual particle beams emanating from the object, Wherein the particle optical configuration has a magnet configuration, the magnet configuration comprising: a first magnetic field region through which the primary particle optical beam path and the secondary particle optical beam path pass, for separating the primary particle optical beam path and the secondary particle optical beam path from each other; a second magnetic field region, disposed in the primary particle optical beam path and not disposed in the secondary particle optical beam path, the second magnetic field region being disposed upstream of the first magnetic field region relative to the primary particle optical beam path, and the first magnetic field region and the second magnetic field region substantially deflect the primary particle optical beam path in different directions; a third magnetic field region, which is disposed in the primary particle optical beam path and is not disposed in the secondary particle optical beam path, the third magnetic field region being disposed upstream of the second magnetic field region relative to the primary particle optical beam path, and the first magnetic field region and the third magnetic field region substantially deflect the primary particle optical beam path in the same direction, An entry direction of the primary particle optical beam path into the third magnetic field region and an exit direction of the primary particle optical beam path from the first magnetic field region are parallel to each other and have no offset.

2. The particle-optical arrangement of claim 1, in, a first drift region substantially free of a magnetic field, arranged in the primary particle optical beam path between the first magnetic field region and the second magnetic field region; and / or The second drift region substantially without a magnetic field is arranged in the primary particle optical beam path between the second magnetic field region and the third magnetic field region.

3. The particle-optical arrangement of claim 1, in, the magnet configuration having a fourth magnetic field region that is configured in the primary particle optical beam path and not configured in the secondary particle optical beam path, wherein the fourth magnetic field region is arranged upstream of the second magnetic field region and downstream of the third magnetic field region relative to the primary particle optical beam path, and The fourth magnetic field region and the second magnetic field region substantially deflect the primary particle optical beam path in the same direction.

4. The particle-optical arrangement according to claim 3, in, a first drift region substantially free of a magnetic field, arranged in the primary particle optical beam path between the first magnetic field region and the second magnetic field region; and / or Wherein, the second drift region substantially without a magnetic field is arranged in the primary particle optical beam path between the second magnetic field region and the fourth magnetic field region; and / or The third drift region substantially without a magnetic field is arranged in the primary particle optical beam path between the fourth magnetic field region and the third magnetic field region.

5. The particle-optical arrangement as claimed in any one of the preceding claims, in, The magnet arrangement has no further magnetic field region in the primary particle optical beam path which is designed to deflect the primary particle optical beam path by more than 2°, in particular by more than 1° or by more than 0.5°.

6. A particle-optical arrangement as claimed in any one of the preceding claims, in, The magnet arrangement is arranged such that no substantial path difference occurs when the first individual particle beam passes through the magnet arrangement.

7. A particle-optical arrangement as claimed in any one of the preceding claims, in, The magnet arrangement has a symmetry plane, and the primary particle optical beam path is mirror-symmetric relative to the symmetry plane when passing through the magnet arrangement.

8. The particle-optical arrangement according to claims 3 and 7, in, The symmetry plane intersects the second magnetic field region.

9. The particle-optical arrangement according to claims 5 and 7, in, The symmetry plane is configured between the second magnetic field region and the fourth magnetic field region.

10. The particle-optical arrangement as claimed in any one of the preceding claims, in, During operation of the particle optical arrangement, the direction of the magnetic field in all magnetic field regions of the magnet arrangement is substantially orthogonal to the optical axis of the primary particle optical beam path, and wherein the magnetic field is substantially uniform.

11. The particle-optical arrangement of claim 10, in, During operation of the particle optical arrangement, said magnetic fields are uniform in the magnetic field region in the primary particle optical beam path, each having an absolute value of magnetic field strength, and wherein said magnetic fields are each assigned a sign characterizing the direction of the magnetic field, and wherein the product of the signed absolute value of the magnetic field strength and the associated arc length in the magnetic field region along which the primary particle optical beam path travels in the magnetic field region is substantially zero when summed up for all magnetic field regions in the primary particle optical beam path.

12. A particle-optical arrangement as claimed in any one of the preceding claims, in, During operation of the particle-optical configuration, the following relation applies to the splitting angle γ of the overall deflection of the primary particle-optical beam path in the first magnetic field region: γ ≥ 2°, in particular γ ≥ 5° or γ ≥ 10°.

13. A particle-optical arrangement as claimed in any one of the preceding claims, in, The overall length of the magnet configuration is defined by the distance between the entry point of the primary particle optical beam path into the third magnetic field region and the exit point of the primary particle optical beam path from the first magnetic field region, and the overall length is less than or equal to 1.0m, in particular less than or equal to 0.5m or less than or equal to 0.3m.

14. A particle-optical arrangement as claimed in any one of the preceding claims, in, Each magnetic field region has an entrance region entering the inclined primary particle optical beam path, and an exit region exiting the inclined primary particle optical beam path, wherein the entry tilt is defined as the angle at which the alignment of the entry region deviates from the normal to the optical axis of the primary particle optical beam path, and wherein the exit tilt is defined as the angle at which the alignment of the exit region deviates from the normal to the optical axis of the primary particle optical beam path, and The departure inclination of the first magnetic field region is 0°.

15. The particle-optical arrangement of claim 14, in, The entry inclination of the third magnetic field region is 0°.

16. A particle optical configuration, further comprising a deflection configuration, which is configured upstream of a third magnetic field region in the direction of a primary particle optical beam path, and is configured to set an entry direction of the primary particle optical beam path into the third magnetic field region, and thereby set an entry inclination, with an accuracy of + / -0.1° or better, in particular + / -0.05° or better, or + / -0.025° or better, and is configured to set an entry position of the primary particle optical beam path into the third magnetic field region with an accuracy of + / -0.3mm or better, in particular + / -0.1mm or better or even + / -0.05mm or better.

17. The particle-optical arrangement of any one of claims 14 to 16, in, The entry inclination of the first magnetic field region is selected such that the exit angle σ of the secondary particle optical beam path from the first magnetic field region is limited to σ≤35°, in particular σ≤25° or σ≤15°.

18. A particle-optical arrangement as claimed in any one of the preceding claims, in, The magnet arrangement has a beam pipe arrangement in which the primary particle optical beam path extends within the magnet arrangement, wherein the beam pipe arrangement has a toroidal topological form.

19. The particle-optical arrangement of claim 18, wherein: During operation of the particle-optical arrangement, the following relation applies to the filling factor F of the beam pipe arrangement: F≤50%, in particular F≤30% or F≤10%.

20. The particle-optical arrangement of any one of claims 1 to 17, in, The magnet arrangement does not include a beam pipe arrangement in which the primary particle optical beam path extends within the magnet arrangement.

21. The particle-optical arrangement of claim 20, in, The magnet arrangement comprises a vacuum chamber in which the primary particle optical beam path extends within the magnet arrangement.

22. A particle-optical arrangement as claimed in any one of the preceding claims, in, The magnet configuration has at least one additional magnetic field region in the secondary particle optical beam path.

23. The particle-optical arrangement of claim 22, in, The magnet is configured to have at least two additional magnetic field regions in the secondary beam path after passing through the first magnetic field region. When the secondary particles have energy changes and their paths form the second particle optical beam path, the at least two additional magnetic field regions are configured to precisely couple the particle optical axis in the secondary beam path into a downstream projection optical unit in terms of offset and angle.

24. The particle-optical arrangement of claim 22, in, The magnet is configured to have at least six additional magnetic field regions and / or quadrupole fields in the secondary beam path after passing through the first magnetic field region. When the secondary particles have energy changes and their paths form the second particle optical beam path, the at least six additional magnetic field regions and / or quadrupole fields are arranged to precisely couple the particle optical axis in the secondary optical beam path into the downstream projection optical unit in terms of offset and angle, and additionally enable near-axis aberration-free, near-axis distortion-free and near-axis dispersion-free imaging.

25. The particle-optical arrangement of any one of claims 22 to 24, in, At least one of the additional magnetic field regions of the secondary particle optical beam path is arranged in a gap between the first magnetic field region and the second magnetic field region of the primary particle optical beam path.

26. The particle-optical arrangement of any one of claims 22 to 25, There is also a magnetic shielding wall arranged between at least one of the magnetic field regions of the primary particle optical beam path and at least one of the magnetic field regions of the secondary particle optical beam path.

27. The particle-optical arrangement of claim 26, wherein: The magnetic shielding wall has an open passage through which the first particle optical beam path passes in a straight line along the particle optical axis when the magnet configuration is closed.

28. The particle-optical arrangement of any preceding claim, wherein the particle-optical arrangement is a multi-beam particle microscope, and wherein the particle-optical arrangement further has the following: a multi-beam particle generator configured to generate a first field of a plurality of charged first individual particle beams; a first particle optical unit having a primary particle optical beam path, arranged to image the generated first individual particle beam onto the object plane such that the first individual particle beam irradiates the object at an incidence position forming a second field; a detection unit having a plurality of detection areas forming a third field; a second particle optical unit having a secondary particle optical beam path arranged to image a second individual particle beam emitted from the incident position in the second field onto the third field of the detection area of ​​the detection system; a magnetic and / or electrostatic objective lens, through which both the first individual particle beam and the second individual particle beam pass; as well as a controller arranged to control particle optical components in the primary particle optical beam path and / or the secondary particle optical beam path and / or components of the magnet arrangement, Wherein, the magnet configuration is configured in the primary particle optical beam path between the multi-beam particle generator and the objective lens, and wherein the magnet configuration is configured in the secondary particle optical beam path between the objective lens and the detection unit.

29. The particle-optical arrangement of claim 28, in, The first individual particle beam is imaged on the object plane and exhibits substantially no field tilt.

30. The particle-optical arrangement of any one of claims 28 to 29, in, The first individual particle beam is imaged into the object plane substantially entirely without distortion, and / or wherein the first individual particle beam is imaged into the object plane substantially without dispersion, and / or Therein, the incident position of the first individual particle beam in the object plane is astigmatic and circular.

31. The particle-optical arrangement of any one of claims 28 to 30, in, The imaging of the first individual particle beam into the object plane is field-free.

32. The particle-optical arrangement of claim 31 , in, The sum of all other second-order and third-order aberrations in the object plane does not exceed 1 nm, in particular does not exceed 0.5 nm or does not exceed 0.25 nm.

Images