Method for operating a multi-particle beam system and multi-particle beam system with electrostatic trapping electrodes

Abstract

A multi-particle beam system and a method for operating it in a decontamination mode are disclosed, in which charged interfering particles located in a sensitive area of ​​a multi-aperture arrangement are captured and removed from the sensitive area. Electrostatic capture electrodes are arranged and controlled in a specific manner, and / or a trench trapping system is used to capture the charged interfering particles. The charged interfering particles are stored during the normal operating mode of the multi-particle beam system in such a way that they do not interfere with normal operation.

Description

Field of invention

[0001] The invention relates generally to multi-particle beam systems that operate with a multitude of charged single-particle beams, such as multi-beam particle microscopes or lithography systems. Specifically, the invention relates to a method for operating a multi-particle beam system and to a multi-particle beam system with electrostatic trapping electrodes and / or a trapping trench system for protecting the micro-optics or multi-aperture arrangement. State of the art

[0002] With the continuous development of increasingly smaller and more complex microstructures, such as semiconductor devices, there is a need for the further development and optimization of planar fabrication techniques and inspection systems for the production and inspection of these small microstructures. The development and fabrication of semiconductor devices, for example, requires verification of test wafer designs, and planar fabrication techniques necessitate process optimization for reliable, high-throughput manufacturing. Furthermore, the analysis of semiconductor wafers for reverse engineering and the customized configuration of semiconductor devices is increasingly required. Therefore, there is a need for inspection tools that can be used with high throughput to examine microstructures on wafers with high accuracy.

[0003] Typical silicon wafers used in the production of semiconductor devices have diameters of up to 300 mm. Each wafer is divided into 30 to 60 repeating sections ("dies") with a size of up to 800 mm. 2A semiconductor device comprises multiple semiconductor structures fabricated in layers on a wafer surface using planar integration techniques. Due to the fabrication processes, semiconductor wafers typically have a flat surface. The feature size of the integrated semiconductor structures ranges from a few micrometers to critical dimensions (CDs) of a few nanometers, with feature sizes expected to become even smaller in the near future. It is anticipated that future feature sizes, or critical dimensions (CDs), will correspond to the 3 nm, 2 nm, or even smaller technology nodes of the International Technology Roadmap for Semiconductors (ITRS). At these small feature sizes, defects of critical dimension size must be identified quickly across a very large area.For several applications, the specification requirement for the accuracy of a measurement provided by an inspection instrument is even higher, for example by a factor of two or an order of magnitude. For example, the width of a semiconductor feature must be measured with sub-1 nm accuracy, such as 0.3 nm or even less, and the relative position of semiconductor structures must be determined with a sub-1 nm superposition accuracy, such as 0.3 nm or even less.

[0004] A more recent development in the field of charged particle microscopes (CPM) is the mSEM, a multi-beam scanning electron microscope. A multi-beam scanning electron microscope is disclosed, for example, in US 7,244,949 B2 and US 2019 / 0355544 A1. In a multi-beam electron microscope, or mSEM, a sample is simultaneously irradiated with a multitude of single-electron beams arranged in a field or grid. For example, 4 to 10,000 (really that many?) single-electron beams can be used as primary radiation, with each single-electron beam separated from an adjacent single-electron beam by a distance of 1 to 200 micrometers. For example, an mSEM has approximately 100 separate single-electron beams (beamlets) arranged, for example, in a hexagonal grid, with the single-electron beams separated by a distance of approximately 10 µm.A multitude of charged single-particle beams (primary beams) are focused by a common objective lens onto the surface of a sample under investigation. The sample can be, for example, a semiconductor wafer mounted on a wafer holder attached to a movable stage. During illumination of the wafer surface with the charged primary single-particle beams, interaction products, such as secondary electrons or backscattered electrons, emanate from the wafer surface. Their starting points correspond to the locations on the sample onto which the multitude of primary single-particle beams are focused. The quantity and energy of the interaction products depend on the material composition and the topography of the wafer surface.The interaction products form several secondary single-particle beams (secondary beams) that are collected by the common objective lens and directed by a projection imaging system of the multi-beam inspection system onto a detector located in a detection plane. The detector comprises several detection areas, each containing several detection pixels, and the detector records an intensity distribution for each of the secondary single-particle beams. This results in an image field of, for example, 100 µm × 100 µm.

[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 stigmatization of the multiple charged single-particle beams. The prior art multi-beam charged particle system also includes at least one intersection plane of the primary or secondary charged single-particle beams. Furthermore, the prior art system includes detection systems to facilitate adjustment. The prior art multi-beam particle microscope includes at least one deflection scanner for collectively scanning an area of ​​the sample surface using the multiple primary single-particle beams to obtain an image field of the sample surface.

[0006] To separate the particle-optical beam path of the primary beams from the particle-optical beam path of the secondary beams, a so-called beam splitter (also called a beam separator or beam divider) is used. This separation is achieved by means of special arrangements of magnetic fields and / or electrostatic fields, for example, using a Wien filter.

[0007] Multi-particle beam systems are generally divided into single-column and multi-column systems. In single-column systems, the individual particle beams pass at least partially through the same particle optics or through one or more global particle lenses. Furthermore, in a single-column system, the individual particle beams are relatively close together. Despite the partially global particle optics, even single-column systems require individual control and / or shaping of the individual particle beams to correct imaging errors such as field curvature, field astigmatism, and other aberrations. A so-called micro-optics unit can be used for this individual control and / or shaping of the individual particle beams. The micro-optics unit often also serves as a multi-beam generator for the production and shaping of a large number of individual particle beams.The multi-beam generator, or micro-optics, comprises a sequence of several multi-aperture plates to generate a multitude of single-particle beams and to shape them so that they possess the necessary properties for subsequent particle-optical imaging. In generating the multitude of single-particle beams, a widened single-particle beam typically strikes a first multi-aperture plate or filter plate and passes through its apertures, resulting in a multitude of single-particle beams instead of a single beam. Subsequent beam shaping using one or more multi-aperture plates employs electrodes, which are positioned, for example, in the aperture area of ​​a multi-aperture plate and can be controlled collectively or individually.The electrodes can be, for example, ring electrodes or multipole electrodes. In another example, a multi-aperture plate can be monolithic, with a voltage applied to the entire plate; that is, the monolithic multi-aperture plate is then at a specific potential, so that its apertures, in conjunction with other particle-optical elements, can create a lensing effect. Other configurations of a multi-aperture plate for active beam shaping are also possible.

[0008] In addition to the described arrangement of multi-aperture plates, the multi-beam generator can also have one or more simple aperture plates with a single central opening, which can be used, for example, as a pre-aperture or as a global electrode for beam shaping.

[0009] For the production of micro-optics, for example MEMS techniques or planar integration techniques are used, i.e. the same processes that are also used for semiconductor manufacturing.

[0010] A reliable and precise multi-beam generator is crucial for a multi-particle beam system. Errors and inaccuracies in the generation and shaping of the individual particle beams impair the subsequent particle-optical imaging. Furthermore, it is essential that all of the multiple individual particle beams are indeed generated and shaped with absolute precision.

[0011] One problem associated with multi-beam generators is contamination, which can occur even when a multi-particle beam system is operated in a high vacuum. Specifically, minute impurities in the form of small solid particles or dust can be present. If these particles settle on or near the multi-beam generator, its multi-aperture array, or in its vicinity, there is a risk that the particles will become charged during operation of the multi-particle beam system or even become embedded in a multi-aperture plate. Charges and electrostatic fields, in turn, negatively affect the shape and / or position of the individual particle beams. The imaging properties of the multi-particle beam system deteriorate. It is therefore desirable to avoid even the slightest contamination of the multi-particle beam generator.

[0012] US 10,861,666 B1 describes the prevention of contamination by dust particles in charged single-beam and multi-particle beam systems, specifically in the region of the (single) particle source or in the region of the emitter / cathode tip (gun or tip). Unwanted discharges in the region of the cathode tip or arc discharges are to be avoided. US 10,861,666 B1 therefore discloses an arrangement near the cathode tip of a capture electrode, in particular annular in shape, which is activated before the actual operation of the emitter, so that charged particles present in the emitter region migrate to the capture electrode and are deposited there. The capture electrode remains activated even during the actual operation of the particle beam system. Furthermore, a shielding element is disclosed to shield the electrostatic field of the capture electrode during normal operation of the particle beam system.Furthermore, according to US 10,861,666 B1, two ring-shaped trapping electrodes can also be used, which are arranged at different positions and with different diameters around the particle-optical axis, but are otherwise used or switched in the same way.

[0013] Although US 10,861,666 B1 also mentions multi-beam particle beam systems, the patent does not address the specific requirements of multi-beam particle beam systems; the particular problem with a multi-beam generator is not mentioned. Description of the invention

[0014] The object of the present invention is to provide an improved multi-particle beam system whose performance is less dependent on existing contamination in the form of small solid particles. In particular, it is an object of the invention to better protect a multi-beam generator or a multi-aperture arrangement of a multi-particle beam system from contamination in the form of solid particles.

[0015] The object of the invention is solved by the subject matter of the independent claims. Advantageous embodiments of the invention are described in the dependent claims.

[0016] According to a first aspect of the invention, it relates to a method for operating a multi-particle beam system, thereby reducing contamination by interfering particles. In principle, the method according to the invention first involves providing a multi-particle beam system with a specific combination of features, then operating the multi-particle beam system in a decontamination mode, and finally operating it in a normal operating mode. These basic process steps are described in more detail below.

[0017] In an initial process step, a multi-aperture particle beam system with a multi-aperture array and at least two capture electrodes is provided. The multi-aperture array can be part of a multi-beam generator, but it can also be located elsewhere or be a separate component within the multi-aperture particle beam system. The multi-aperture array comprises a plurality of multi-aperture plates, each of which has a multi-aperture region with a plurality of apertures and an outer area surrounding the multi-aperture region. In a normal operating mode of the multi-aperture particle beam system, the plurality of apertures in the multi-aperture region is penetrated by a plurality of charged single-particle beams. In particular, the single-particle beams can be generated in this way. The multi-aperture region of the multi-aperture array is part of the sensitive region of the multi-aperture array.In the sensitive area, contamination by interfering particles, and especially by charged interfering particles, is particularly disruptive because it affects the generated single-particle beams. The outer area surrounding the multi-aperture region is less sensitive in this respect. This outer area typically does not have any apertures, at least not for the standard operation of a multi-particle beam system in its normal operating mode. However, (other) apertures may be provided in the outer area, for example, for adjustment or current measurement purposes. The outer area directly adjacent to the multi-aperture region is also normally considered part of the sensitive area of ​​the multi-aperture array. In this inner boundary region of the outer area, charged interfering particles can generate interference fields, and from this boundary region of the outer area, charged interfering particles can also migrate to the multi-aperture region and generate interference fields there.

[0018] The first capture electrode is essentially circumferential around the particle-optical axis Z of the multi-particle beam system. Furthermore, it is projected along the direction of the particle-optical axis onto the multi-aperture arrangement in its outer region. In other words, the first capture electrode is located above or below the outer region, and not slightly above or below the multi-aperture region.

[0019] The same applies to the second capture electrode: This is arranged around the particle-optical axis Z of the multi-particle beam system and projected along the direction of the particle-optical axis Z onto the multi-aperture arrangement in its outer region. The second capture electrode is positioned further away from the particle-optical axis than the first capture electrode.

[0020] Following the initial process step of deploying the multi-aperture particle beam system, the system is operated in a decontamination mode in which charged interfering particles are trapped in the sensitive area of ​​the multi-aperture array. This decontamination mode comprises the following steps (a) to (c) in the specified order: In step (a), the same potential is applied to the multi-aperture arrangement, to the first trapping electrode, and to the second trapping electrode. This identical potential could be, for example, ground potential, but this is not necessarily the case.

[0021] In step (b), the potential at the first trapping electrode is changed, and a first electrostatic trapping field is generated between the first trapping electrode and the multi-aperture array, allowing charged interfering particles to migrate from the multi-aperture array to the first trapping electrode. The sign of the potential at the first trapping electrode, or the direction of the first electrostatic trapping field, is advantageously chosen such that charged interfering particles with a specific sign can be trapped in the first electrostatic trapping field by the first trapping electrode and move away from the multi-aperture array. The sign of the charge, in turn, is determined by the specific characteristics of the multi-particle beam system.For example, if a high-energy electron beam is used in the normal operating mode of the multi-particle beam system, such as with electrons accelerated to several keV (e.g., 20 keV, 25 keV, 30 keV or more), negatively charged ions are to be expected near the multi-aperture array, making a positive capture potential at the first capture electrode advantageous. Similarly, a large number of backscattered secondary electrons in the region of the multi-aperture array, for example, within the multi-beam generator vacuum chamber, can predominantly lead to the formation of negatively charged interfering particles, so here too a positive potential at the first capture electrode may be beneficial. These considerations generally apply equally to all capture electrodes.

[0022] In step (c), the potential at the second trapping electrode is changed, and a second electrostatic trapping field is generated between the second and first trapping electrodes. This second electrostatic trapping field is stronger than the first, allowing charged particles to migrate from the first to the second trapping electrode. Preferably, this transfers charged particles initially captured by the first trapping electrode to the second trapping electrode. It is also possible, of course, for previously uncaptured charged particles to be captured directly by the second trapping electrode.

[0023] After performing process steps (a), (b), and (c) of the decontamination mode, the multi-particle beam system is then operated in a normal operating mode, in which the multi-aperture arrangement is penetrated by, or generated by, the multitude of charged single-particle beams. In this normal operating mode, the same potential is applied to the multi-aperture arrangement and the first capture electrode. Furthermore, a different potential is applied to one of the other capture electrodes than to the multi-aperture arrangement, so that the charged contaminants remain at this capture electrode, which serves as a storage capture electrode, during normal operating mode. If exactly two capture electrodes are provided in the area of ​​the multi-aperture arrangement, the second capture electrode automatically becomes the storage capture electrode.By providing the same potential at the multi-aperture arrangement and at the first capture electrode, it is avoided that an electrostatic field from the capture electrode negatively affects beam generation and shaping by the multi-aperture arrangement during normal operation. Preferably, ground potential is present at the multi-aperture arrangement and at the first capture electrode during normal operation, but this is not mandatory.

[0024] According to a preferred embodiment of the invention, more than two capture electrodes are provided in the area of ​​the multi-aperture arrangement, wherein, in normal operating mode, a different potential is provided at exactly one of the capture electrodes than at the multi-aperture arrangement. This reduces electrostatic interference fields that can result from capture electrodes or from only one storage capture electrode.

[0025] According to a preferred embodiment of the invention, the one capture electrode or storage capture electrode at which a different potential than at the multi-aperture arrangement is provided is the capture electrode located furthest outward with respect to the particle-optical axis Z of the multi-particle beam system. This storage capture electrode is thus furthest from the sensitive area of ​​the multi-aperture arrangement, which is why any residual fields or interference fields have the least influence on the charged single-particle beams there.

[0026] According to a preferred embodiment of the invention, in the decontamination mode after step (c) the following process step is further carried out: In step (d), the potential at the first capture electrode is changed, without altering the direction of the second electrostatic capture field. This measure facilitates the transfer of charged particles from the first to the second capture electrode. Several methods exist for changing the potential at the first capture electrode: In one implementation, the potential at the first capture electrode is reduced in magnitude while maintaining its sign. This reduction can be abrupt or continuous, or it can occur in several equal steps. In another implementation, the potential at the first capture electrode is set to ground potential. It is also possible to initially reduce the potential while maintaining its sign and then finally set it to ground potential.In another embodiment, the potential of the first capture electrode is reversed. Instead of merely weakening the first electrostatic capture field, this allows for the active repulsion of charged interfering particles at the first capture electrode. This can be advantageous, for example, when the first and second capture electrodes are relatively far apart. The reversal can also be performed continuously, stepwise, or in a single step.

[0027] According to a preferred embodiment of the invention, a third capture electrode is provided, which is arranged circumferentially around the particle-optical axis Z of the multi-particle beam system and projected along the direction of the particle-optical axis onto the multi-aperture arrangement in its outer region. The third capture electrode is arranged further away from the particle-optical axis Z than the second capture electrode. According to this embodiment of the invention, after step (c) and, in particular, after the optional step (d), the following further step is carried out in the decontamination mode: In step (e), the potential at the third capture electrode is changed, and a third electrostatic capture field is generated between the third and second capture electrodes. This third electrostatic capture field is stronger than the second, allowing charged particles to migrate from the second to the third capture electrode. The same principles apply to this transfer of charged particles from the second to the third capture electrode as were already described regarding the migration of charged particles from the first to the second capture electrode.

[0028] It is also important here that charged interfering particles are first transferred from the second capture electrode to the third capture electrode before the potential at the second capture electrode is changed in a further process step (f). Again, the direction of the third electrostatic capture field is not changed. The potential at the second capture electrode can therefore, for example, be reduced in magnitude while maintaining its sign, the potential at the second capture electrode can be set to ground potential, or the potential at the second capture electrode can be reversed. These changes can be carried out stepwise, continuously, or in a single step.

[0029] Analogous considerations apply if one or more additional capture electrodes are provided besides the third. By gradually transferring charged interfering particles from one capture electrode to the next, these particles can be progressively moved further away from the sensitive area of ​​the multi-aperture arrangement before being finally captured at the last and outermost capture electrode, the storage capture electrode.

[0030] According to a preferred embodiment of the invention, in normal operating mode the electrostatic field of the storage capture electrode is shielded so that it does not interfere with beam shaping or single-beam shaping. Various technical means can be used for this shielding. For example, it is possible to provide a special electrostatic shield or shielding element in the area of ​​the multi-aperture arrangement. It is also possible to arrange one or more of the other annular capture electrodes or transfer capture electrodes in such a way that this arrangement provides a shielding effect. Other elements of the multi-particle beam system can also be used for shielding purposes, for example, a beam tube in which a charged particle beam or in which charged particle beams are guided.

[0031] According to a preferred embodiment of the invention, at least one of the capture electrodes is not used for beam shaping in the normal operating mode of the multi-particle beam system. In this embodiment, at least one additional, separate capture electrode is therefore provided in the area of ​​the multi-aperture arrangement of the multi-particle beam system.

[0032] Additionally or alternatively, at least one of the capture electrodes is used as a capture electrode in decontamination mode and for beam shaping in the normal operating mode of the multi-particle beam system. This embodiment of the invention takes into account the fact that a multi-beam generator often has one or more simple aperture plates with a central opening in addition to the multi-aperture arrangement. This single aperture plate is used, for example, as a pre-aperture or as a suction electrode in normal operating mode and thus contributes fundamentally to beam shaping. Structurally, this single aperture plate already has all the properties that a capture electrode should also have: It is arranged around the particle-optical axis Z of the multi-particle beam system and projected onto the multi-aperture arrangement in its outer area along the direction of the particle-optical axis. The single aperture plate, orIts opening is often slightly larger than the multi-aperture area. This offers an elegant way to use the existing electrode or single aperture plate as a capture electrode in decontamination mode. Naturally, such a single aperture plate is only a transfer capture electrode and not the final storage capture electrode. This would significantly disrupt operation in normal mode.

[0033] According to a preferred embodiment of the invention, a plurality of capture electrodes, arranged circumferentially around the particle-optical axis Z and projected along the direction of the particle-optical axis onto the multi-aperture arrangement in its outer region, are provided both above and below the multi-aperture arrangement with respect to the particle-optical beam path. In simplified terms, a group of at least two capture electrodes is located above the multi-aperture arrangement, and another group of at least two capture electrodes is located below the multi-aperture arrangement. According to this embodiment of the invention, process steps (a) to (c) are now carried out using the respective capture electrodes both above and below the multi-aperture arrangement. This takes into account the fact that charged interfering particles naturally occur both on the source side, i.e.,They may be present above the multi-aperture array as well as on the object side, i.e. below the multi-aperture array, and must be removed.

[0034] Interfering particles are not only found on the upper or lower surfaces of the multi-aperture arrangement, but can also migrate into the apertures within the arrangement and cause interference during the normal operating mode of the multi-particle microscope. To remove interfering particles from inside the multi-aperture arrangement, one embodiment of the invention provides the following: In decontamination mode, a first suction potential is applied to an upper multi-aperture plate of the arrangement, and a second suction potential is applied to a lower multi-aperture plate. The first suction potential is different from the second suction potential.This allows charged particles from the interior of the multi-aperture arrangement to be virtually sucked out between the upper and lower multi-aperture plates due to the electrostatic field applied between them. The upper multi-aperture plate can be the topmost plate of the arrangement, which is advantageous but not mandatory. The same applies to the lower or bottommost multi-aperture plate. A potential difference between the first and second suction potentials is typically several hundred volts, e.g., 100 V, 200 V, or 300 V. After the charged particles have been sucked out of the interior of the multi-aperture arrangement, the decontamination of the arrangement or its surface area can then proceed, in particular by carrying out process steps (a) to (c) of the invention.

[0035] According to a preferred embodiment of the invention, in decontamination mode and in particular before step (a), the following step (g) is further carried out: In step (g), the multi-aperture arrangement is irradiated to electrostatically charge interfering particles. This irradiation can be carried out in different ways. It is possible to irradiate the multi-aperture arrangement directly with charged particles. This can be done, for example, using a flood gun. However, it is also possible for a particle source, which initially generates a beam of single-particle charged particles, to be operated in a different mode or in a different manner than in a normal operating mode for the source or emitter.

[0036] Furthermore, the irradiation of the multi-aperture arrangement for the electrostatic charging of interfering particles can also be achieved indirectly by selecting a different irradiation method, in which charged particles such as electrons are generated in a further interaction step. This includes irradiating the multi-aperture arrangement with UV radiation as well as irradiating the surroundings of the multi-aperture arrangement with X-rays. This generates secondary electrons through interaction processes, which can then be used for the electrostatic charging of interfering particles.

[0037] According to a preferred embodiment of the invention, the multi-aperture arrangement is irradiated on both the source and object sides with respect to the particle-optical beam path. This can be achieved, firstly, by providing the irradiation source on the respective sides of the multi-aperture arrangement. However, it is also possible to employ reflection and scattering processes for bi-sided irradiation of the multi-aperture arrangement.

[0038] According to a preferred embodiment of the invention, a beam stop is inserted into the particle-optical beam path below the multi-aperture arrangement, so that when the beam stop is irradiated through the multi-aperture arrangement, the irradiating charged particles are backscattered and thereby irradiate the multi-aperture arrangement on the object side. This is particularly advantageous when charged particle beams, and especially electron beams, are used for irradiation, particularly from the particle source already mentioned, which is already integrated into the multi-particle beam system. The backscattering of the charged particles towards the multi-aperture arrangement can optionally be supported by suitable control of one or more electrodes, which can be arranged between the multi-aperture arrangement and the inserted beam stop.

[0039] According to a further preferred embodiment of the invention, the method in decontamination mode and in particular after steps (g) and (h) comprises the following step (i): In step (i), vibrations are applied to the multi-aperture assembly. This application of vibrations facilitates the removal of charged interfering particles adhering to a surface or within the multi-aperture assembly. The actual removal of particles from a surface is more difficult than the mere transfer of charged interfering particles from the multi-aperture assembly to the first capture electrode or, more generally, to one of the capture electrodes. This additional energy required for the removal process is provided by the vibrations.

[0040] The multi-aperture arrangement as a whole is often designed as a tongue, meaning that one of its lateral ends can oscillate freely. However, other oscillating configurations are also conceivable. The vibrations at the multi-aperture arrangement can be provided in various ways: According to a preferred embodiment of the invention, the provided vibrations include mechanical vibrations. For example, it is possible to subject the multi-aperture arrangement itself to such vibrations. The multi-aperture arrangement is designed to withstand these mechanical vibrations without damage. According to an alternative or additional embodiment of the invention, the provided vibrations include acoustic vibrations and / or ultrasonic vibrations. No damage is observed at vibration levels up to 120 dB in a corresponding multi-aperture arrangement.

[0041] According to a further preferred embodiment of the invention, the method in decontamination mode, and in particular after steps (g) and (h), comprises the following step: In step (j), an alternating electric field is provided near the surface of the multi-aperture arrangement, the direction of which is oriented essentially parallel to one of the surfaces of the multi-aperture arrangement. This alternating electric field can also set a charged perturbation particle in motion and, in particular, detach it from the surface of the multi-aperture arrangement or at least orient it so that detachment by means of the capture electrodes can be achieved.

[0042] The various methods that support the removal of charged particles can, of course, be combined. It is particularly advantageous to harmonize one frequency of alternating electric fields with another vibration frequency. In this way, the different methods can mutually support and enhance each other.

[0043] It is possible to combine the different embodiments and variants in whole or in part according to the first aspect of the invention, provided that this does not result in any technical contradictions.

[0044] According to a second aspect of the invention, it relates to a multi-particle beam system, which can be, for example, a multi-beam particle microscope or a lithography system. The multi-particle beam system according to the invention comprises a multi-beam generator with a multi-aperture arrangement, wherein the multi-aperture arrangement has a plurality of multi-aperture plates, each of which has a multi-aperture region with a plurality of apertures and an exterior area around the multi-aperture region. In a normal operating mode of the multi-particle beam system, the plurality of apertures is penetrated by a plurality of charged single-particle beams. In normal operating mode, for example, a plurality of real or imaginary particle sources can be imaged onto an object plane or sample plane.In addition to the multi-aperture arrangement, the multi-beam generator can have other features, for example it can also include simple or singular aperture plates that can function as global electrodes or particle lenses in normal operating mode.

[0045] The multi-particle beam system according to the invention further comprises a first trapping electrode which is arranged around the particle-optical axis Z of the multi-particle beam system and projected along the direction of the particle-optical axis Z onto the multi-aperture arrangement in its outer area.

[0046] Furthermore, the multi-particle beam system has a second trapping electrode which is arranged around the particle-optical axis Z of the multi-particle beam system and projected along the direction of the particle-optical axis Z onto the multi-aperture arrangement in its outer area.

[0047] Furthermore, the multi-particle beam system according to the invention has a mode selection device for operating the multi-particle beam system in normal operating mode or in a decontamination mode, wherein in the decontamination mode charged interfering particles from a sensitive area of ​​the multi-aperture arrangement comprising the multi-aperture area are captured by means of the capture electrodes. The sensitive area comprises not only the multi-aperture area but also an adjacent area of ​​the outside and designates the area in which the presence of charged interfering particles would adversely affect the beam shaping in the normal operating mode of the multi-particle beam system.

[0048] Furthermore, the multi-particle beam system according to the invention includes a control unit for controlling the multi-particle beam system. The control unit can be a central control unit or it can be subdivided into several modules. According to the invention, the control unit is configured to provide an adjustable potential at the first capture electrode and to provide an adjustable potential at the second capture electrode. Adjustable here means selectable. It is possible that two predetermined potentials can be provided according to ON / OFF, but it is also possible that the potential can be continuously varied. In particular, the potential at the first capture electrode is adjustable independently of the potential at the second capture electrode. The two potentials are therefore individually adjustable. Furthermore, the control unit is configured to provide a potential, in particular ground potential, at the multi-aperture arrangement.The control system is configured to provide the same potential, and in particular ground potential, to the multi-aperture arrangement and the electrostatic shielding element. This can also be a passive provision if the multi-aperture arrangement and the electrostatic shielding element are simply grounded. The potential only needs to be provided; it does not necessarily have to be variable. Such a multi-particle beam system is particularly suitable for carrying out the method described above for operating the multi-particle beam system as described in the first aspect of the invention.

[0049] The potential provided at the multi-aperture arrangement can be adjustable. However, it is also possible that this potential is not adjustable and a constant potential, in particular ground potential, is provided at the multi-aperture arrangement. As described in connection with the first aspect of the invention, the successful application of a decontamination mode depends on the potential differences between the first capture electrode, the second capture electrode, and the multi-aperture arrangement, not on the absolute values ​​of the provided potential(s). The trivial case in which the multi-aperture arrangement is simply grounded and requires no control whatsoever is explicitly included in the wording of independent claim 22.

[0050] Using the mode selection device, a user of the system can, for example, switch between normal operation and decontamination mode. It is also possible for the system to remind the user, after a certain operating time of the multi-particle beam system, to temporarily operate it in decontamination mode. Furthermore, the system can be implemented to automatically initiate decontamination mode whenever, for example, the multi-particle beam system, and in particular a multi-beam generator vacuum chamber, has been vented and the air or gas subsequently pumped out of the chamber to re-establish a vacuum or high vacuum. The mode selection can then be confirmed by the user, for example, via a switch or a selection button on a display.However, it is also possible that a mode selection device is inherently implemented within the multi-particle beam system and that the mode selection is made based on process parameters of the multi-particle beam system.

[0051] According to a preferred embodiment of the invention, the multi-particle beam system according to the invention further comprises an electrostatic shielding element that is arranged on a surface of the multi-aperture arrangement and protrudes from this surface, surrounding the multi-aperture area of ​​the multi-aperture arrangement. The electrostatic shielding element thus essentially has a ring structure. It can form a kind of barrier on a surface of the multi-aperture arrangement. The electrostatic shielding element can be integrally formed with the surface of the multi-aperture arrangement. In addition to its electrostatic shielding function, the electrostatic shielding element also forms a mechanical barrier against interfering particles.charged interference particles that can move on or around the surface of the multi-aperture arrangement and thereby risk penetrating the sensitive area of ​​the multi-aperture arrangement, which would be disruptive to the normal operating mode of the multi-particle beam system.

[0052] When the electrostatic shielding element is provided, the second trapping electrode and the electrostatic shielding element are arranged at the same height relative to the particle-optical beam path, so that the electrostatic shielding element can shield the electrostatic field of the second trapping electrode in normal operating mode. The second trapping electrode and the electrostatic shielding element are therefore located next to each other, which is advantageous for shielding the second trapping electrode. In contrast, the first trapping electrode is arranged above the second trapping electrode and above the electrostatic shielding element relative to the particle-optical beam path.

[0053] If a multi-particle beam system configured in this way is used to carry out the method for operating a multi-particle beam system according to the first aspect of the invention, the second capture electrode can be used as a storage capture electrode. It is then the only capture electrode that actively generates an electrostatic field in normal operating mode, which must be shielded.

[0054] In a decontamination mode, for example, an electric field between the multi-aperture array and the first capture electrode first transports a potentially present charged interfering particle from the multi-aperture array to the first capture electrode. In a second step, the interfering particle is transported from the first capture electrode to the second capture electrode. Afterward, the first capture electrode can be switched off, while the second capture electrode remains activated as a storage capture electrode. Therefore, in normal operating mode, the electric field of the first capture electrode does not need to be shielded; this is only necessary for the second capture electrode and its field. For this purpose, the electrostatic shielding element described is sufficient.

[0055] According to a preferred embodiment of the invention, the first capture electrode is arranged closer to the particle-optical axis than the second capture electrode, and / or the first capture electrode is located further away from the particle-optical axis than the electrostatic shielding element. This is a particularly advantageous arrangement of the first capture electrode, as it can then effectively act as a bridge in the transfer of charged interfering particles from the sensitive area of ​​the multi-aperture arrangement to the storage capture electrode or the second capture electrode.

[0056] According to a preferred embodiment of the invention, the shielding element comprises a shielding ring whose profile is essentially triangular. It is, of course, possible for the "corners" of the profile to be rounded. The essentially triangular profile is thus wider at the surface of the multi-aperture arrangement than in an upper region. It tapers upwards, preferably continuously. The shielding element can therefore have a wall-like or dike-like structure, which not only enables electrostatic shielding but also forms a good mechanical barrier against any charged interfering particles. The shielding element can have a height h A exhibit properties for which: 0.5 mm ≤ h A ≤ 10.0 mm, preferably 0.5 mm ≤ h A ≤ 5.0mm.

[0057] According to a preferred embodiment of the invention, the multi-beam generator is arranged in a multi-beam generator vacuum chamber into which an evacuable beam tube opens on the particle source side, in which charged particles are guided. It is generally known to guide the particle-optical beam path in a multi-particle beam system within an evacuable beam tube. Furthermore, it is generally known to arrange certain features or components of a multi-particle beam system not within the beam tube, but within a special vacuum chamber. These vacuum chambers or high-vacuum chambers, in which a high vacuum with 10 -9 mbar or better, they offer more space than the jet tube itself.

[0058] According to a preferred embodiment of the invention, the presence of a multi-beam generator vacuum chamber can be utilized for shielding purposes: In a preferred embodiment of the invention, the first and second trapping electrodes are arranged such that they are laterally retracted behind an imaginary extension of the beam tube towards the multi-aperture arrangement. This prevents the first and second trapping electrodes from being struck by the individual particle beams of the multi-particle beam system, even during normal operation. The cylindrical, grounded beam tube also serves as an electrostatic shielding element in this embodiment of the invention.

[0059] According to a further preferred embodiment of the invention, the multiple particle beam system comprises at least two additional trapping electrodes arranged around the particle-optical axis Z of the multiple particle beam system and projected along the direction of the particle-optical axis onto the multi-aperture arrangement in its outer region, and which are arranged below the multi-aperture arrangement relative to the particle-optical beam path. The control system is configured to control the additional trapping electrodes and to provide an individually adjustable potential at each trapping electrode. In this embodiment of the invention, the multiple particle beam system thus comprises a total of at least four trapping electrodes, two of which are arranged above the multi-aperture arrangement and two below it.In this way, it is possible to transfer and store potentially present interfering particles both above and below the multi-aperture arrangement using the capture electrodes.

[0060] According to a preferred embodiment of the invention, the profile of one of the trapping electrodes is neither circular nor elliptical. It is also possible for all trapping electrodes to be neither circular nor elliptical. The profile of the trapping electrodes is therefore not standard, but can be specifically designed to shape and influence the electrostatic trapping field generated by the trapping electrodes. For example, this makes it possible to increase the field strength at the trapping electrode, thus enabling better capture of charged particles.

[0061] According to a further preferred embodiment of the invention, the multi-particle beam system further comprises a flood gun for irradiating the multi-aperture arrangement, wherein the control system is configured to activate the flood gun in decontamination mode for irradiating the multi-aperture arrangement. The flood gun can be positioned above the multi-aperture arrangement, i.e., on the source side, or it can be positioned below the multi-aperture arrangement, i.e., on the object side. The flood gun is arranged in such a way that it does not interfere with the normal particle-optical beam path of the multi-particle beam system. Using the flood gun, the multi-aperture arrangement can be irradiated very precisely with charged particles, such as electrons, in order to selectively charge any existing interfering particles before the actual decontamination process.

[0062] Additionally or alternatively, according to one embodiment of the invention, the multi-particle beam system comprises a particle source for generating a charged particle beam. The multi-particle beam system is configured to direct the charged particle beam as an illuminating particle beam onto the multi-aperture arrangement. This can be achieved in a known manner by appropriately controlling the particle source itself, including the cathode, anode, suppressor, etc., and / or by appropriately controlling a condenser lens system or collimation lens system. In this embodiment of the invention, the control system is further configured to control the particle source, which can be operated in a normal operating mode and in a flooding mode. In the flooding mode, the particle source emits fewer charged particles and / or charged particles with lower energy than in the normal operating mode.By providing a flooding mode for the particle source, it is therefore possible to do without a separate flood cannon.

[0063] According to a further preferred embodiment of the invention, the multi-particle beam system comprises a UV source and / or an X-ray source for irradiating the multi-aperture arrangement. The UV source and / or an X-ray source can also be used to irradiate the multi-aperture arrangement, whereby this irradiation cannot and should not be direct, but only indirect. In secondary processes, charged particles such as ions or electrons, in particular secondary electrons, are also generated during these irradiation processes, which can be used to charge interfering particles on the multi-aperture arrangement.

[0064] According to a preferred embodiment of the invention, the multi-particle beam system further comprises a beam stop that can be inserted into the particle-optical beam path in the lower region of the multi-beam generator vacuum chamber. The beam stop is configured to backscatter incident charged particles, so that charged particles backscattered from the beam stop can irradiate the multi-aperture arrangement from the rear. For example, the beam stop can close off the lower region of the multi-beam generator vacuum chamber. It can, for example, be provided on or in combination with a valve on the multi-beam generator vacuum chamber.

[0065] According to a preferred embodiment of the invention, the multi-aperture arrangement is designed as a tongue, and a vibration generator is arranged on the multi-aperture arrangement. The control system is then configured to activate the vibration generator in decontamination mode. The vibration generator can, for example, be located at the end of the tongue in the vibrating area of ​​the multi-aperture arrangement. However, it can also be located at another point on the multi-aperture arrangement. Alternatively, the multi-aperture arrangement can also be designed to vibrate in a different way. The multi-aperture arrangement can also be designed in a form other than tongue-shaped. The vibration generator can, for example, provide mechanical vibrations or acoustic vibrations. Both result in a mechanical movement or vibration of the multi-aperture arrangement as a whole, which helps to detach charged contaminant particles from a surface of the multi-aperture arrangement.easier to resolve before these charged interfering particles are captured by the trapping electrodes.

[0066] According to a preferred embodiment of the invention, the multi-particle beam system comprises a field-generating means for generating an alternating electric field, wherein the field-generating means is arranged close to the surface of the multi-aperture arrangement. The field-generating means is preferably multi-part and can, for example, be configured as a capacitor, and in particular as a plate capacitor. The field-generating means is configured to generate an alternating electric field in decontamination mode, which is oriented parallel to the surface of the multi-aperture arrangement. Such field generation contributes to the removal of charged contaminant particles from the surface of a multi-aperture arrangement. The influence of the alternating electric field reduces the contact area of ​​the contaminant particle, effectively causing it to stand upright, which facilitates its subsequent capture by the capture electrodes.The frequencies of the alternating electric field can be chosen, for example, so that the corresponding wavelength roughly corresponds to the dimensions of a particle. Typically, this is about 10. -5 m to about 10 -3 m.

[0067] According to a further preferred embodiment of the invention, the multi-particle beam system comprises a pumping system with at least one vacuum pump. Preferably, the pumping system includes more than one vacuum pump. The pumping system can, for example, include a so-called turbomolecular pump and / or an ion getter pump. The pumping system is connected to the multi-beam generator vacuum chamber by means of a pumping line system. This pumping line system can be branched or unbranched. According to this embodiment of the invention, at least one particle trap for capturing charged interfering particles is arranged within this pumping line system, but not within the pumps themselves. Although there are pumps on the market that are specified as non-particle-evolving, it has nevertheless been observed that individual particles can be observed in the multi-beam generator vacuum chamber that appear to originate from a pump. Particle traps within the vacuum pumps or...High-vacuum pumps, therefore, do not appear to be sufficient in every case to completely eliminate contaminants. It is also possible that air vents contribute to contaminants reaching the multi-aperture assembly; valves are not specifically specified as "non-particle-evolving." These facts are addressed by the additional provision of particle traps within the pumping system, i.e., within pipes or lines.

[0068] According to one embodiment of the invention, a particle trap is arranged directly upstream of the inlet to the multi-beam generator vacuum chamber. Alternatively, a particle trap can be arranged directly downstream of a vacuum pump outlet. The former prevents the ingress of interfering particles into the multi-beam generator vacuum chamber if the particles have already entered the pumping system. The latter combats or captures interfering particles directly after their formation. Of course, it is also possible to provide multiple particle traps in the pumping system, with one particle trap located directly upstream of the inlet to the multi-beam generator vacuum chamber and another particle source positioned directly downstream of the vacuum pump outlet. This configuration can be applied to all pumps.

[0069] According to one embodiment of the invention, the particle source comprises a capacitor and a flood gun for emitting charged particles, in particular electrons. The capacitor can be designed, for example, as a parallel-plate capacitor or a cylindrical capacitor. The capacitor and the flood gun are arranged such that they are sequentially permeated by a gas stream during the ventilation of the multi-beam generator vacuum chamber. The order of the arrangement is important: The flood gun is positioned upstream of the capacitor in the pumping line system, in the direction of the gas stream used to ventilate the multi-beam generator vacuum chamber. This ensures that the ventilation gas stream first passes through the flood gun and only then through the capacitor. As a result, unwanted particles can first be charged by the flood gun and then captured by an electrostatic field from the capacitor.Furthermore, in this embodiment of the invention, the control system is configured to operate the capacitor for providing an electric field and the flood gun for emitting charged particles during a ventilation process of the multi-jet generator vacuum chamber. The ventilation process is critical here, while the venting and pumping process is less critical. Only at a relatively high pressure in the pumping system, for example ≥ 1 mbar, is the airflow strong enough to actually transport potential contaminants based on the airflow. This pressure corresponds to the critical time interval during which charged contaminants can be transported into the multi-jet generator vacuum chamber by the gas flow. After this pressure, this mechanism becomes irrelevant and effectively ceases to occur at lower pressures.

[0070] According to a preferred embodiment of the invention, the control system is configured to limit the gas flow through the pumping line system during a critical time interval and to operate the particle trap during this critical interval. This only marginally increases the overall time for the venting process. Theoretically, the venting of the multi-jet generator vacuum chamber could also be performed more quickly. However, this would result in more particles being entrained and potentially deposited in the area of ​​the multi-aperture arrangement. Therefore, it is advantageous to control the venting process and limit the gas flow so that, virtually in passing, more interfering particles can be charged and captured by the particle trap than with a larger gas flow or airflow. It should be noted that while a similar deposit problem can arise during a venting process, it is not inevitable.This depends on the specific arrangement of the pumps and the specific execution of the venting process. Therefore, even during a venting process, it can be advantageous to control the process and limit the gas flow.

[0071] According to a further embodiment of the invention, the particle trap comprises a first capacitor and a second capacitor. The first and second capacitors are arranged such that they are successively traversed by a gas stream during the ventilation of the multi-jet generator vacuum chamber. Compared to the embodiment described above, the flood gun is thus replaced by a second capacitor. Again, the arrangement sequence of the first and second capacitors is important: The first capacitor is positioned upstream of the second capacitor in the pumping line system, in the direction of the gas stream used to ventilate the multi-jet generator vacuum chamber. The control system is configured to control the first capacitor to provide an alternating electric field and the second capacitor to provide a non-alternating electrostatic field.Initially neutral particles are charged in the first capacitor and trapped in the second capacitor.

[0072] In this embodiment of the invention, the control system is also preferably configured to limit the gas flow through the pump line system during a critical time interval of the aeration and / or venting process and to activate the particle trap during this critical time interval. Preferably, the critical time interval is the time interval corresponding to the time interval during which the pressure in the pump line system is ≥ 1 mbar during aeration.

[0073] According to a third aspect of the invention, this relates to a multi-particle beam system, such as a multi-beam particle microscope or a lithography system. Unlike the first and second aspects of the invention, the third aspect provides a passive solution for capturing charged interfering particles. In particular, it is possible to combine this passive solution with active solutions.

[0074] The multi-particle beam system according to the invention comprises a multi-beam generator with a multi-aperture arrangement, wherein the multi-aperture arrangement includes a plurality of multi-aperture plates. Each of the multi-aperture plates has a multi-aperture region with a plurality of apertures and an outer area around the multi-aperture region, wherein the plurality of apertures is penetrated by a plurality of charged single-particle beams in a normal operating mode of the multi-particle beam system. A first multi-aperture plate of the multi-aperture arrangement is provided, wherein this first multi-aperture plate is the first to be penetrated by the plurality of charged particles. This first multi-aperture plate is therefore the uppermost multi-aperture plate, which can also be referred to as a pre-multi-aperture plate or a filter plate.According to the invention, this first multi-aperture plate has a trapping trench system in its outer surface, comprising at least one trapping trench for capturing charged interfering particles. The trapping trench system acts, firstly, as a mechanical barrier for interfering particles located in the trapping trench. Secondly, the trapping trench system increases the surface area of ​​the first multi-aperture plate, which in turn increases the interaction between charged interfering particles and the surface, for example, due to van der Waals forces. This, in turn, reduces the momentum of the interfering particles and any movement of the interfering particles. As a result, fewer interfering particles enter the sensitive area of ​​the first multi-aperture plate.

[0075] According to a preferred embodiment of the invention, the first multi-aperture plate, including the trapping trench system, has a metallic layer for stopping and absorbing charged particles that strike it. The provision of such a metallic layer is generally known and is now extended to the trapping trench system according to the invention.

[0076] In the normal operating mode of the multi-aperture particle beam system, the multi-aperture array or the multi-aperture plates are at a defined potential, for example, ground potential. Doped silicon, with or without an additional metal coating, can be used as the material for the multi-aperture plates, and especially for the first multi-aperture plate. This takes into account the fact that most multi-aperture arrays use the same manufacturing processes as are common in semiconductor manufacturing.

[0077] According to a preferred embodiment of the invention, the at least one trap trench is formed around the multi-aperture area. It can be formed completely or intermittently. The more completely the multi-aperture area is enclosed by the at least one trap trench, the better the trapping effect of the trench.

[0078] According to a preferred embodiment of the invention, the surrounding trap trench has one or more interruptions. The inclusion of such interruptions may be due to the manufacturing process of the trap trench. For the same reason, a trap trench is preferably designed to be linear in sections. For example, it is possible to surround the multi-aperture area of ​​the first multi-aperture plate with a trap trench consisting of four linear sections. Each trap trench can be produced, for example, by an etching process. The entire multi-aperture area can then be surrounded by a rectangular or square trap trench structure. However, other overall configurations of a trap trench system with at least one trap trench are also possible.

[0079] According to a preferred embodiment of the invention, the cross-sectional shape of a trap trench is essentially rectangular, essentially triangular, or essentially circular. Additionally or alternatively, a trap trench can be produced using etching techniques. Anisotropic or isotropic etching processes can be employed. Rectangular or triangular cross-sections are most easily produced using anisotropic etching processes, while circular cross-sectional shapes, which approximately represent a segment of a circle, are best produced using isotropic etching processes.

[0080] According to a preferred embodiment of the invention, the interceptor system comprises a sequence of interceptor trenches extending away from the multi-aperture area, with at least one first inner interceptor trench and a second interceptor trench arranged further outwards. The interceptor system can, of course, also include a third, fourth, fifth, etc., interceptor trench. The sequence of interceptor trenches further increases the surface area of ​​the first multi-aperture plate. Furthermore, by providing a sequence of interceptor trenches, the movement of interfering particles towards the sensitive inner area of ​​the first multi-aperture plate can be further reduced: Potential movement requires multiple exchanges of kinetic and potential energy, which is accompanied by losses due to frictional forces. Therefore, the movement of interfering particles can be slowed down.

[0081] According to a preferred embodiment of the invention, the first interceptor trench has a first cross-section and the second interceptor trench has a second cross-section. The shape of the first cross-section and the shape of the second cross-section are identical, and their dimensions are also identical. Thus, the first and second interceptor trenches are largely identical in design; only their overall length differs. Such an interceptor trench system is particularly easy to manufacture.

[0082] According to an alternative embodiment of the invention, the first trap trench has a first cross-section and the second trap trench has a second cross-section, wherein the shape of the first cross-section and the shape of the second cross-section are identical. However, the dimensions of the first and second cross-sections are different in this embodiment. For example, it is possible that both the first and second trap trenches have a substantially triangular cross-section, but that the first and second trap trenches are of different depths. By varying the dimensions of the cross-sections, other design features of the multi-aperture arrangement can be tailored to suit specific requirements. According to a preferred embodiment of the invention, the entire multi-aperture area of ​​the first multi-aperture plate is arranged in a central trench, and the outer area of ​​the first multi-aperture plate is essentially not located in this central trench. It is then advantageous that the trench depth of the sequence of intercepting trenches arranged in the outer area increases from the inside out. This makes it possible to design the first multi-aperture plate to be more stable overall.

[0083] According to a preferred embodiment of the invention, the entire multi-aperture area of ​​the first multi-aperture plate is arranged in a central trench, wherein the following relationship applies for a depth t of the central trench: 10µm ≤ t ≤ 200µm.

[0084] According to a preferred embodiment of the invention, the following relationship applies to the trench depth t of a trap: 10 µm ≤ t ≤ 200 µm, preferably 10 µm ≤ t ≤ 20 µm or 10 µm ≤ t ≤ 18 µm. This relationship can also apply to all traps of the trap system. The trench depth t is readily achievable during the manufacturing processes of the first multi-aperture plate. Furthermore, the trench depth is adapted to the typical size of interfering particles, which range from the upper nanometer range down to approximately 1 µm. These types of interfering particles can be effectively trapped in traps with the corresponding trench depth t.

[0085] Additionally or alternatively, the following relationship can apply for a maximum trench width b of a trap trench: 8 µm ≤ b ≤ 12 µm.

[0086] The maximum width of the interceptor trench is measured at its widest point. Depending on the cross-sectional shape, this can be at the bottom of the trench, at the entrance, or within the trench itself (for example, in the case of a circular, bowl-shaped design). The maximum trench width b can be greater or less than the trench depth t. Generally, however, it is preferable that, at least for some interceptor trenches, the trench depth t is greater than the maximum trench width b. Shallower trenches are chosen primarily for stability reasons. Deeper interceptor trenches generally provide better interceptor function. Additionally or alternatively, the following relationship can apply to the distance a between adjacent interceptor trenches: b / a ≥ 1.5, preferably b / a ≥ 2.0.

[0087] This makes it possible to significantly increase the surface area of ​​the first multi-aperture plate. However, the distance between adjacent interceptor trenches must not become too small, so as not to compromise the stability of the first multi-aperture plate.

[0088] According to a preferred embodiment of the invention, the multiple particle beam system further comprises a particle source for generating a charged particle beam. The multiple particle beam system is then configured to direct the charged particle beam as an illuminating particle beam onto the multi-aperture arrangement. This can be achieved, for example, by means of a condenser lens system comprising one or more magnetic lenses or electrostatic lenses, or combinations thereof. Furthermore, the multiple particle beam system is configured, in a normal operating mode, to illuminate the multi-aperture area of ​​the first multi-aperture plate and to essentially not illuminate the outer area of ​​the first multi-aperture plate. As a result, in a normal operating mode, the trapping trench system is also not illuminated, and any interfering particles located therein are not further charged.

[0089] According to a further preferred embodiment of the invention, the multi-particle beam system can have a pre-aperture that truncates a widened particle beam before it strikes the multi-aperture arrangement. This pre-aperture can be configured in a stepped manner, for example, with exactly one step. The step can represent an additional mechanical barrier for interfering particles on the path to the multi-aperture arrangement that approach the particle source side of the arrangement. Additionally or alternatively, an exit aperture can be provided downstream of the multi-aperture arrangement, which can also be configured in a stepped manner, for example, with exactly one step. This step can, in turn, represent an additional mechanical barrier for interfering particles on the path to the multi-aperture arrangement that approach the object side of the arrangement.

[0090] The embodiments according to the third aspect of the invention can in turn be combined wholly or partially with one another.

[0091] Furthermore, it is possible to combine the embodiments according to the first, the second and the third aspect of the invention, provided that this does not result in any technical contradictions.

[0092] The invention will be better understood with reference to the accompanying figures. These show: Fig. 1: schematically shows a multi-particle beam system; Fig. 2: schematically shows a structure of a multi-beam generator with a multi-aperture arrangement; Fig. Figure 3: schematically shows arrangements of a multi-beam generator in multiple particle beam systems; Fig. 4: schematically shows the structure of a multi-aperture arrangement; Fig. 5: schematically shows a multi-aperture arrangement with capture electrodes; Fig. 6: schematically shows a multi-aperture arrangement with capture electrodes; Fig. Figure 7: schematically illustrates a method for operating a multi-particle beam system; Fig. Figure 8: schematically shows a multi-aperture arrangement with trapping electrodes and an electrostatic shielding element; Fig. Figure 9: schematically shows the process steps for operating a multi-particle beam system; Fig. Figure 10: schematically shows further process steps for operating a multi-particle beam system; Fig. 11: schematically illustrates a rearward irradiation of a multi-aperture arrangement; Fig. 12: schematically illustrates a suction process of charged interfering particles from the interior of a multi-aperture arrangement; Fig. Figure 13: schematically illustrates the removal of charged perturbation particles from a surface of a multi-aperture arrangement using an alternating electric field; Fig. Figure 14: schematically shows a multi-aperture arrangement with a vibration generator; Fig. 15: schematically shows a pumping system of a multi-particle beam system with a particle trap; Fig. Figure 16: schematically shows a particle trap in a pumping system; Fig. 17: schematically shows an arrangement of particle traps in a pumping system; Fig. 18: schematically shows a first multi-aperture plate with a trench system in a top view; Fig. 19: schematically shows trenches in a sectional view; Fig. 20: schematically shows trenches in a sectional view; Fig. 21: schematically shows trenches in a sectional view; Fig. Figure 22: schematically shows a first multi-aperture plate with a central trench and a trap trench system in a sectional view; and Fig. Figure 23: schematically shows a multi-aperture arrangement with a preceding pre-aperture and a subsequent exit aperture, each of which is graduated.

[0093] Fig. Figure 1 schematically shows a multi-particle beam system 1 in the form of a multi-beam particle microscope 1. The multi-beam particle microscope 1 has a beam generation device 300 with a particle source 301, for example, an electron source. A diverging particle beam 309 is collimated by a sequence of condenser lenses 303.1 and 303.2 and strikes a multi-beam particle generator 305 with a multi-aperture arrangement. The multi-beam particle generator 305 comprises several multi-aperture plates 304, 306 and a field lens 307. The multi-beam particle generator 305 generates a multitude of single-particle beams 3 or single-electron beams 3, which are arranged in a field that is imaged onto another field formed by beam spots 5 in the object plane 101. The distance between the centers of apertures of a multi-aperture plate 306 can be, for example, 5 µm, 100 µm and 200 µm.The diameters D of the apertures are smaller than the distance between the centers of the apertures; examples of the diameters are 0.2 times, 0.4 times, and 0.8 times the distances between the centers of the apertures.

[0094] The multi-aperture arrangement 305 and the field lens 308 are configured to generate a multitude of focal points 323 of primary beams 3 in a grid arrangement on a surface 321. The surface 321 need not be a flat surface, but can be a spherically curved surface to accommodate field curvature of the subsequent particle optical system.

[0095] The multi-beam particle microscope 1 further comprises a system of electromagnetic lenses 103 and an objective lens 102, which reduce the size of the beam foci 323 from the intermediate image surface 325 onto the object plane 101. The first individual particle beams 3 pass through the beam splitter 400 and a collective beam deflection system 500, which deflects the multitude of first individual particle beams 3 during operation and scans the image field. The first individual particle beams 3 incident on the object plane 101 form, for example, a substantially regular field, with distances between adjacent point locations 5 being, for example, 1 µm, 10 µm, or 40 µm. The field formed by the point locations 5 can, for example, have a rectangular or hexagonal symmetry.

[0096] The object 7 to be examined can be of any type, for example a semiconductor wafer or a biological sample, and it can comprise an array of miniaturized elements or the like. The surface 15 of the object 7 is located in the object plane 101 of the objective lens 102. The objective lens 102 can comprise one or more electron-optical lenses. It can be, for example, a magnetic objective lens and / or an electrostatic objective lens.

[0097] The primary particles 3 striking object 7 generate interaction products such as secondary electrons, backscattered electrons, or primary particles that have undergone a reversal of motion for other reasons. These products originate from the surface of object 7 or from the first plane 101 or object plane 101. The interaction products emanating from the surface 15 of object 7 are shaped into secondary particle beams 9 by the objective lens 102. After passing through the objective lens 102, the secondary beams 9 pass through the beam splitter 400 and are directed to a projection system 200. The projection system 200 has an imaging system 205 with projection lenses 206, 208 and 210, a contrast aperture 214 and a multi-particle detector 207. The impact points 25 of the second single-particle beams 9 on the detection areas of the multi-particle detector 207 are located in a third field at a regular distance from each other.Examples of values ​​are 10 µm, 100 µm and 200 µm.

[0098] The multi-beam particle microscope 1 further comprises a computer system or a control unit or controller 10, which in turn may be designed as a single unit or as a multi-part unit, and which is designed both for controlling the individual particle-optical components of the multi-beam particle microscope 1 and for evaluating and analyzing the signals obtained with the multi-detector 207 or the detection unit.

[0099] Further information on such multi-beam particle beam systems or multi-beam particle microscopes 1 and components used therein, such as particle sources, multi-aperture plates and lenses, can be obtained from the international patent applications WO 2005 / 024881 A2, WO 2007 / 028595 A2, WO 2007 / 028596 A1, WO 2011 / 124352 A1 and WO 2007 / 060017 A2 and the German patent applications DE 10 2013 016 113 A1 and DE 10 2013 014 976 A1, the disclosure of which is incorporated in full by reference into the present application.

[0100] Fig. Figure 2 shows an example of a micro-optics 305 configured as a multi-beam generator 305. In the example shown, the multi-beam generator 305 comprises, in the z-direction, which corresponds to the propagation direction of the single-particle beams 3, a sequence of six multi-aperture plates 304, 306.1, 306.2, 306.3, 306.4, and 310, as well as a global field lens 307. Each of the multi-aperture plates 304, 306.1 to 306.4, and 310 comprises a plurality of apertures 351, each of which is penetrated by the plurality of single-particle beams 3. The cross-section through the apertures 351 in Fig. Figure 2 is not to scale.

[0101] The multiple multi-aperture plates 304, 306.1, 306.2, 306.3, 306.4, and 310 are spaced apart from each other by spacers 83.1 to 83.5. Furthermore, a spacer 86 is provided between the final multi-aperture plate 310 and the global lens electrode 307. When a collimated particle or electron beam 309 passes through the first multi-aperture plate 304, also called the filter plate or pre-aperture plate, the multiple individual particle beams 3 are generated. The pre-aperture plate 304 comprises a metallic layer 99 on its beam-entry side for stopping and absorbing the charged particles or electrons of the electron beam 309 around the multiple apertures 85. In the example shown, the material of the preparation plate 304 is made of a conductive material, e.g. doped silicon, and is at earth potential.

[0102] The next multi-aperture plate is in the example shown. Fig. 2 a multi-stigmator plate 306.1. The multi-stigmator plate 306.1 comprises a plurality of four or more electrodes 82, e.g., eight electrodes for each of the apertures. During operation of the multi-beam particle microscope 1, different voltages, for example, in the range between -20 V and +20 V, can be applied to each of these electrodes, thereby influencing each individual particle beam 3 individually. For example, it is possible to deflect each individual particle beam 3 in any direction down to a few µm using an antisymmetric voltage difference in order to pre-correct a distortion correction of the illuminating unit 100. Astigmatism pre-correction of each individual particle beam 3 can thus be performed. With an offset voltage, each multipole element can additionally function as a single lens.

[0103] The multi-aperture plates 306.2, 306.3, and 306.4 can, in principle, be any monolithic path correction plates, each subjected to a voltage V1, V2, and V3, respectively, as shown in the example. It is also possible for the multi-aperture plates 306.2, 306.3, and 306.4 to form a single-lens array. Different apertures 351 within the same multi-aperture plate 306.2, 306.3, and 306.4 can be identical or different, for example, having different diameters, in order to account for the field dependence of the correction when correcting the path of the individual particle beams 3.

[0104] The multi-aperture plate 310 is a two-layer multi-aperture plate comprising a plurality of ring electrodes 79 for the plurality of apertures, each ring electrode being configured to individually modify or correct a focal position of the first single-particle beam 3 passing through it. The upper layer is insulated from the layer containing the ring electrodes 79 and is made of a conductive material such as doped silicon.

[0105] The field lens 307 comprises a ring electrode 84 to which a high voltage of, for example, 3 kV to 20 kV can be applied, e.g., 12 kV to 17 kV. In the example shown, the field lens 307 provides a global electrostatic lens field for global focusing of the multitude of individual particle beams 3.

[0106] The in Fig. The micro-optics 305 shown, or their multi-aperture plates, can in principle be manufactured using known manufacturing processes or planar integration techniques.

[0107] Fig. Figure 3 schematically shows arrangements of a multi-beam generator 305 in multiple particle beam systems 1. Fig. Figure 3a) shows a system with a multi-beam generator 305, which has a multi-lens array with several multi-aperture plates 304, 306 on the one hand, i.e., a multi-aperture arrangement 305, and a counter electrode or simple aperture plate 307. In contrast, the system according to Fig. Figure 3b shows a multi-beam generator 305 comprising a multi-aperture arrangement 352 and a multi-deflector array 353. In this embodiment, the multi-deflector array 353 can also be considered part of the multi-aperture arrangement. Furthermore, it is of course possible to replace the multi-aperture plate 352 with several multi-aperture plates; the illustration in Figure 3 therefore only shows the principle of the multi-beam generators 305.

[0108] Due to the different generation of the multitude of single-particle beams 3, the actual image with the two in Fig. 3a and Fig. The systems shown in 3b differ: While in Fig. 3a a multiple real image of the particle source 301 with focal point 323 in the plane E1 is formed, in the execution variant according to Fig. 3b Foci 323 are viewed as virtual particle sources and images of the real particle beam source 301. In both cases, foci 323 are mapped onto the plane E2, in which the surface of object 7 is positioned, by a particle-optical imaging technique.

[0109] Furthermore, in both cases, the multi-beam generator 305 is illuminated with a charged particle beam after this charged particle beam has passed through a condenser lens system 303. The illumination can be collimated ( Fig. 3a) or convergent or divergent ( Fig. 3b - the divergent case is shown). After passing through the multi-beam generator 305, the generated single-particle beams 3 each pass through a field lens system 108, which provides various degrees of freedom for adjusting imaging properties. Subsequently, a beam splitter 400 is passed through before the single-particle beams 3 are imaged by an objective lens system 102 onto the plane E2 on the surface of the object 7. The secondary beam path for secondary beams 9 originating from the surface of the sample 7 is shown in Fig. 3 not shown for the sake of simplicity.

[0110] Fig. Figure 4 schematically shows the setup of a multi-aperture arrangement 350. In the example shown, charged particles are emitted from a particle source 301. A potential of several kV can be applied to the particle source 301, for example, + / - 20 kV, + / - 25 kV, + / - 30 kV. This is shown in Fig. 4. Then an extractor electrode, at which, for example, a potential of a few kV, e.g., + / - 3 kV, + / - 4 kV, or + / - 5 kV, is applied. The charged particle beam 309 then passes through an electrode or aperture 399, which in the example shown is at ground potential. Subsequently, the charged particle beam 309 passes through a condenser lens system 303.1 and 303.2, which, in the example shown, enables the divergent entry of the charged particle beam 309, or the subsequently illuminating particle beam 311, into the electrostatic field of a pre-counter electrode 398. However, entry into this electrostatic field of the pre-counter electrode 398 could also occur convergently or telecentrically. The charged particle beam 311 then collides telecentrically with a first multi-aperture plate 304 with a multitude of round apertures, so that the multitude of single particle beams 3 are formed at this first multi-aperture plate 304 as they pass through the multi-aperture plate 304.In the next step, the single-particle beams 3 are shaped, in the example shown by means of a sequence of further multi-aperture plates 306.1, 306.2 and 306.3 as well as by means of the simple aperture plate or field lens 307, which represents a counter electrode for separating the single-particle beams 3, so that the foci 323 in the intermediate image plane are further apart.

[0111] In the example shown, the multi-aperture plates 304, 306.1, 306.2, and 306.3 form a multi-aperture arrangement 350. A potential can be individually applied to the multi-aperture plates 304 and 306.3 by means of a controller 10 (not shown). It is also possible to apply ground potential to the multi-aperture plates 304 and 306.3. An individually adjustable potential can also be provided to the pre-counter electrode 398 and the counter electrode 307 by means of the controller 10. While in the example shown the first multi-aperture plate 304 and the final multi-aperture plate 306.3 are preferably at ground potential, a relatively high voltage of several kV is applied to the pre-counter electrode 398 and the counter electrode 307, e.g., approximately + / -10 kV, + / -15 kV, or + / -20 kV. The sign depends on the potential of the emitter 301 or the counter electrode 307.The charge sign of the charged particles forming the particle beams 309, 311, and 3 is given. In the example shown, the multi-aperture plate 306.1 has a plurality of ring electrodes that can be individually controlled by the controller 10 to individually set a focal position of the single particle beam 3 passing through them. In the example shown, the multi-aperture plate 306.2 has individually controllable multipole lenses around each aperture. However, it would also be possible to design, shorten, or supplement the sequence of multi-aperture plates 304, 306.1, 306.2, and 306.3 of the multi-aperture arrangement differently.

[0112] A reliable and precise multi-beam generator 305 is crucial for the good imaging properties of a multi-particle beam system 1. Even the smallest impurities in the form of small solid particles or dust negatively affect the generation and shaping of the individual particle beams 3 and thus the imaging properties of the multi-particle beam system 1. If interfering particles accumulate on or near the multi-beam generator 305 or its multi-aperture arrangement 350, there is a risk that the particles will become charged during operation of the multi-particle beam system 1 or even be burned into the micro-optics 305. Therefore, one countermeasure is to provide trapping electrodes in the area of ​​the multi-aperture arrangement 350. Fig. Figure 5 schematically shows a multi-aperture arrangement 350 with two capture electrodes 361 and 362. For simplification, in Fig. 5 an excerpt from Fig. Figure 4 is shown for illustrative purposes. However, the multi-aperture arrangement 350 could also be configured differently than in the example shown. In the example shown, the first trapping electrode 361 is arranged around the particle-optical axis Z of the multiple particle beam system 1 and is projected onto the multi-aperture arrangement 350 in its outer region along the direction of the particle-optical axis Z. The trapping electrode 361 is therefore not located within the region of the multiple apertures, but rather further away from the particle-optical axis Z than the multiple apertures. In the example shown, the first trapping electrode 361 is ring-shaped and arranged between the pre-counter electrode 398 and the first multi-aperture plate or filter plate 304. Furthermore, in Fig. 5 A second trapping electrode 362 is arranged downstream of the final multi-aperture plate 306.3 and upstream of the counter electrode or field lens 307 with respect to the particle-optical beam path. In the example shown, the second trapping electrode 362 is also a ring electrode, arranged circumferentially around the particle-optical axis Z of the multi-aperture particle beam system, and is projected along the direction of the particle-optical axis Z onto the multi-aperture arrangement 350 in its outer region. Unlike the first trapping electrode 361, the second trapping electrode 362 is partially surrounded by an electrostatic shield 370. This is advantageous when the second trapping electrode 362 is used as a storage trapping electrode; in a normal operating mode of the multi-aperture particle beam system 1, an electrostatic field of the trapping electrode 362 can then be shielded by the shield 370.It is also possible to provide the first capture electrode 361 with further shielding; the one in . Fig. The embodiment shown in Figure 5 illustrates only the principle for an arrangement of capture electrodes 361, 362 both above and below the multi-aperture arrangement 350 with respect to the particle-optical beam path. In general, in a decontamination mode of the multi-particle beam system, in which charged interfering particles are captured in a sensitive area of ​​the multi-aperture arrangement 350, a potential is applied to the capture electrodes 361, 362. This potential causes the charged interfering particles to migrate from the multi-aperture arrangement 350 to the capture electrodes 361, 362, where they are captured. The details of the method that can be used for this purpose will be discussed further below.

[0113] Fig. Figure 6 schematically shows another multi-aperture arrangement 350 with a plurality of capture electrodes 361, 362, 363, 364 and 365. In the example shown, the multi-beam generator 305 with the multi-aperture arrangement 350 is arranged within a multi-beam generator vacuum chamber 380, which is in Fig. 6 is only partially indicated. An illuminating particle beam 311 passes through a grounded beam tube 371 into the multi-beam generator vacuum chamber 380 and irradiates the multi-aperture arrangement 350 there for the purpose of generating and shaping the individual particle beams 3. Specifically, the multi-aperture area 350 with its multitude of apertures is essentially irradiated, while the outer area 356 around the multi-aperture area 355 is essentially not irradiated, but could be at least partially irradiated if the illuminating particle beam 311 were appropriately expanded. The multi-aperture area 355 and directly adjacent areas of the outer area 356 form the sensitive region of the multi-aperture arrangement 350. In this sensitive region, interfering particles, and in particular charged interfering particles 701, 702, have a negative influence on the beam shaping.In the example shown, an exemplary interfering particle 701 is located on the upper side of the multi-aperture arrangement 350, and another interfering particle 702 is located on the rear side of the multi-aperture arrangement 350. To capture these interfering particles 701 and 702, several capture electrodes 361, 362, 363, 364, and 365 are provided both above and below the multi-aperture arrangement 350. All capture electrodes 361, 362, 363, 364, and 365 are arranged around the particle-optical axis Z of the multi-particle beam system 1 and projected along the direction of the particle-optical axis Z onto the multi-aperture arrangement 350 in its outer area 356. They are also retracted laterally behind an imaginary extension of the beam tube 371 to the multi-aperture arrangement 350. In the example shown, the trapping electrodes 361 and 363 are arranged at the same height z2.The second trapping electrode 362 is located at height z1, and thus closer to the surface of the multi-aperture arrangement 350. The diameter of the first trapping electrode 361 is smaller than the diameter of the second trapping electrode 362, which in turn is smaller than the diameter of the third trapping electrode 363. In the example shown, by means of a control mechanism for the trapping electrodes 361, 362, and 363, as well as the multi-aperture arrangement 350 (to be described in more detail later), it is possible to successively move a charged interfering particle 701 first to the first trapping electrode 361, then to the second trapping electrode 362, and then to the third trapping electrode 363, and to store it at the third trapping electrode 363 even during normal operation of the multi-particle beam system 1. The trapping electrode 363 that is furthest from the particle-optical axis Z is therefore used as the storage trapping electrode 363.Furthermore, it is due to the special arrangement of the two remaining storage electrodes 361 and 362 in . Fig. 6. It is possible to shield the electrostatic potential of the third trapping electrode 363 in normal operating mode by the two trapping electrodes 361 and 362. The grounded, ring-shaped beam tube 371 can also serve as additional shielding.

[0114] Below the multi-aperture arrangement 350, two trapping electrodes 364 and 365 are arranged in the example shown. These have no beam-shaping function in a normal operating mode of the multi-particle beam system 1. In normal operating mode, however, the counter electrode 307 – as described in connection with Fig. As described in section 4, the counter electrode 307 is used for beam shaping. In decontamination mode, however, this counter electrode 307, due to its ring-shaped or rotating design around the particle-optical axis Z, can also be used as a capture electrode. It is simply not suitable for permanent use as a storage capture electrode. In a decontamination mode of the multi-particle beam system 1, it is therefore possible to move a charged interfering particle 702 first to the counter electrode 307, then to the capture electrode 364, and finally to the capture electrode 365. The interfering particle 702 can then be stored at the capture electrode 365 as a storage capture electrode 365.

[0115] Similarly, a pre-counter electrode 398 could also be used, as in Fig. 4 described, can be used as a trapping electrode, for example instead of the first trapping electrode 361.

[0116] Fig. Figure 7 schematically illustrates a method for operating a multi-particle beam system 1. In the initial process step S1, the multi-particle beam system 1 is first provided with a multi-aperture arrangement 350 and, in the described example, with 3 trapping electrodes, for example the trapping electrodes 361, 362 and 363, as shown in Fig. Figure 6 shows the multi-aperture arrangement 350, which comprises a plurality of multi-aperture plates, each of which 304, 306 has a multi-aperture region 355 with a plurality of apertures 85, 351 and an outer area 356 around the multi-aperture region 355. In a normal operating mode of the multi-particle beam system 1, the plurality of apertures 85, 351 is penetrated by a plurality of charged single-particle beams. A first trapping electrode 361 is arranged around the particle-optical axis Z of the multi-particle beam system 1 and projected along the direction of the particle-optical axis Z onto the multi-aperture arrangement 350 in its outer area 356. The same applies to the second trapping electrode 362 and the third trapping electrode 363.The second trapping electrode is positioned further away from the particle-optical axis Z than the first trapping electrode, and the third trapping electrode is positioned further away from the particle-optical axis Z than the second trapping electrode.

[0117] In an optional process step S2, the multi-aperture arrangement 350 is irradiated to electrostatically charge interfering particles 701, 702 in the described example. For this purpose, it is possible, for example, to use a flood gun to irradiate the multi-aperture arrangement 350 and to control this flood gun in decontamination mode for this irradiation of the multi-aperture arrangement 350. However, it is also possible to use the particle source 301 already present in the multi-particle beam system 1 for this charging process of interfering particles. The control system 10 can be configured to control or operate the particle source 301 in a normal operating mode and in a flooding mode, whereby the particle source 301 imitates fewer charged particles and / or charged particles with lower energy in the flooding mode than in the normal operating mode.Additionally or alternatively, it is also possible to use a UV source and / or an X-ray source to irradiate the multi-aperture arrangement 350 in step S2, whereby secondary electrons are generated by means of secondary processes, for example, which can in turn irradiate the multi-aperture arrangement 350. Overall, it is advantageous if, during irradiation according to step S2, the multi-aperture arrangement 350 is irradiated both on the source side and on the object side with respect to the particle-optical beam path.

[0118] In a further process step S3, the multi-particle beam system 1 is operated in a decontamination mode, whereby in step S3 the same potential is first provided at the multi-aperture arrangement 350, at the first trapping electrode 361, at the second trapping electrode 362 and at the third trapping electrode 363. This potential can be ground potential.

[0119] In process step S4, the potential at the first trapping electrode 361 is changed by means of the control system, thereby generating a first electrostatic trapping field between the first trapping electrode 361 and the multi-aperture arrangement 350. A charged interfering particle 701 can therefore migrate from the multi-aperture arrangement 350 to the first trapping electrode 361.

[0120] In step S5, the potential at the second trapping electrode 362 is changed, and a second electrostatic trapping field is generated between the second trapping electrode 362 and the first trapping electrode. This second electrostatic trapping field is stronger than the first. Thus, the charged interfering particle 701 can migrate from the first trapping electrode 361 to the second trapping electrode 362.

[0121] In process step S6, the potential of the first trapping electrode 361 is changed in the example shown, without altering the direction of the second electrostatic trapping field. This change can be achieved, for example, by decreasing the magnitude of the potential at the first trapping electrode 361 while maintaining its sign, by setting the potential at the first trapping electrode to ground potential, or by reversing the polarity of the potential at the first trapping electrode 361. The simplest method is to set the potential at the first trapping electrode 361 back to ground potential. The change in the potential at the first trapping electrode 361 only occurs once the charged interfering particle 701 has been reliably moved from the first trapping electrode 361 to the second trapping electrode 362; thus, the interfering particle 701 is not lost from the first trapping electrode 361 due to a change in its potential.A safe transfer of the interfering particle 701 is therefore guaranteed.

[0122] In process step S7, the potential at the third trapping electrode 363 is changed, and a third electrostatic trapping field is generated between the third trapping electrode 363 and the second trapping electrode 362. Again, the third electrostatic trapping field is stronger than the second electrostatic trapping field, allowing the charged interfering particle 701 to migrate from the second trapping electrode 362 to the third trapping electrode 363.

[0123] In process step S8, the potential at the second trapping electrode 362 is changed, without altering the direction of the third electrostatic trapping field. It is again possible to decrease the magnitude of the potential at the second trapping electrode 362 while maintaining its initial value, to set the potential at the second trapping electrode to ground potential, or to reverse the polarity of the potential at the second trapping electrode 362. The simplest option is to set the potential at the second trapping electrode back to ground potential.

[0124] Optionally, it is also possible to change the potential applied to the second trapping electrode 362 between process steps S5 and S6, in particular to lower it. This allows the potential applied to the third trapping electrode 363 in step S6 to be selected such that the third electrostatic trapping field is stronger than the second electrostatic trapping field, but only needs to be as strong overall as the second electrostatic trapping field was at the beginning of its formation in process step S5. This makes it possible to successively transfer charged interfering particles 701 from one trapping electrode to the next without requiring the electrostatic trapping field to become progressively stronger.

[0125] In process step S9, the multi-particle beam system 1 is then operated in its normal operating mode by permeating the multi-aperture arrangement 350 with the multitude of charged single-particle beams 3, and in particular by means of these - as for example in Fig. 1 and Fig. Figure 3 is shown – mapped onto an object plane 101. In process step S9, the same potential is provided at the multi-aperture arrangement 350, the first trapping electrode 361, and the second trapping electrode 362 in normal operating mode. However, a different potential is provided at the third trapping electrode 363 than at the multi-aperture arrangement 350. In this way, charged interfering particles 701 can remain at this third trapping electrode 363, which in the described example represents a storage trapping electrode 363, during normal operating mode. Preferably, ground potential is present at the first trapping electrode 361, the second trapping electrode 362, and at least at the multi-aperture plate 304 of the multi-aperture arrangement that is closest to the trapping electrodes. In this way, the method according to the invention is particularly easy to carry out.

[0126] Similarly, the described method for operating a multiple particle beam system 1 can also be carried out for a plurality of trapping electrodes that are not arranged above the multi-aperture arrangement 350, but below it (compare, for example, the illustration in Fig. 6) In this context, it is also possible to use electrodes already provided near the multi-aperture arrangement 350, which serve for beam shaping in normal operating mode, as capture electrodes in decontamination mode.

[0127] Depending on the size of the interfering particles and / or their charge state, it may be difficult to remove charged interfering particles 701 directly from a surface of the multi-aperture arrangement 350 using electrostatic capture fields. Therefore, according to a preferred embodiment of the invention, an additional process step is proposed for the initial or partial removal of charged interfering particles 701 from the surface of the multi-aperture arrangement 350. This process step for removing the interfering particles 701 can be implemented in various ways: For example, vibrations can be applied to the multi-aperture arrangement 350. These vibrations can include, for example, mechanical vibrations or sound or ultrasonic vibrations.An additional or alternative possibility is to provide an alternating electric field near the surface of the multi-aperture arrangement 350, wherein the direction of the electric field is oriented parallel or antiparallel to one of the surfaces of the multi-aperture arrangement. Such an alternating electric field makes it possible for a charged interfering particle 701 to stand upright on the surface of the multi-aperture arrangement 350, if not completely detach, which facilitates its removal by means of the electrostatic capture field.

[0128] Fig. Figure 8 schematically shows a multi-aperture arrangement 350 with trapping electrodes 361, 362 and an electrostatic shielding element 372. The multi-aperture arrangement 350, the trapping electrodes 361, 362 and the electrostatic shielding element 372 shown can in turn be part of a multi-particle beam system 1, which is equipped with a mode selection device to operate the multi-particle beam system 1 in a normal operating mode and in a decontamination mode, as has already been described several times above. Fig. In Figure 8, the first trapping electrode 361 is arranged as the first trapping electrode 361 after the opening of the beam tube 371 to a multi-beam generator vacuum chamber 380. The trapping electrode 361 is laterally retracted behind an imaginary extension of the beam tube 371 towards the multi-aperture arrangement 350. The first trapping electrode 361 is arranged circumferentially around the particle-optical axis Z of the multi-particle beam system 1 and is projected along the direction of the particle-optical axis Z onto the multi-aperture arrangement 350 in its outer area 356. In the example shown, the first trapping electrode 361 is designed as a ring electrode and has a diameter D1. The second trapping electrode 362 is also designed as a ring electrode in the example shown and has a larger diameter D2 than the first trapping electrode 361. Furthermore, the second trapping electrode 362 is positioned very close to the multi-aperture arrangement 350.In the sensitive region of the multi-aperture arrangement 350, i.e. in the multi-aperture region 355 or near the multi-aperture region 355, charged perturbation particles 701 and 702 and 703 are in . Fig. Figure 8 is shown. In the example shown, the electrostatic shielding element 372 is arranged between these interfering particles 701, 702, 703 and the second trapping electrode 362. Specifically, the electrostatic shielding element 372 is located on a surface of the multi-aperture arrangement and protrudes from this surface, as well as surrounding the multi-aperture area 355 of the multi-aperture arrangement 350. The electrostatic shielding element 372 provides a ring-like or ridge-like structure which, due to its arrangement, is suitable for shielding an electrostatic trapping field at the second trapping electrode 362 during operation of the multi-particle beam system 1 in normal operating mode. The second trapping electrode 362 and the electrostatic shielding element 372 are arranged at essentially the same height with respect to the particle-optical beam path. In the example shown, the electrostatic shielding element 372 is positioned slightly higher.extends higher than the second trapping electrode 362. In contrast, the electrostatic shielding element 372 is not designed to be so tall as to also shield the first trapping electrode 361. Instead, the fundamental idea is to arrange the two trapping electrodes 361, 362 and the electrostatic shielding element in such a way that progressively charged interfering particles 701, 702 can first be transferred from the multi-aperture arrangement 350 or from the electrostatic shielding element 372 to the first trapping electrode 361 and then further transferred to the second trapping electrode 362. In the normal operating mode of the multi-particle beam system 1, this serves as a storage trapping electrode 362 and can be shielded by the electrostatic shielding element 372. The first trapping electrode 361 can simply be switched off or...The first trapping electrode 361 is set to ground potential so that no electrostatic field or interference field exists there. Therefore, with respect to the particle-optical beam path, the first trapping electrode 361 is arranged above the second trapping electrode 362 and above the electrostatic shielding element 372.

[0129] The same potential, in particular ground potential, is present at the electrostatic shielding element 372 and at the multi-aperture arrangement 350, or rather at its surface, in both decontamination mode and normal operating mode. It is also possible to form the shielding element 372 integrally with the multi-aperture arrangement 350 itself. In the example shown, the shielding element 372 is designed as a shielding ring whose profile is essentially triangular. The corners of the essentially triangular profile are preferably rounded. The essentially triangular profile has two advantages: Firstly, it is easy to manufacture; secondly, the shape of the profile of the electrostatic shielding element 372 allows the electrostatic field formed between this shielding element 372 and the first capture electrode 361 in decontamination mode to be shaped, thus enabling higher field strengths to be provided for the capture process due to the shape.However, other shapes besides an essentially triangular shape for the electrostatic shielding element 372 are also possible.

[0130] Fig. Figure 9 schematically shows the process steps for operating a multi-particle beam system 1 in a decontamination mode. The detailed description is provided in Figure 9. Fig. 8 replaced by a more schematic representation. Fig. Figure 9a shows an initial process step in which the same potential, for example earth potential, is provided at the multi-aperture arrangement 350 including the electrostatic shielding 372 and also at the first trapping electrode 361 and at the second trapping electrode 362.

[0131] In Fig. Figure 9b shows the situation with a changed potential at the first trapping electrode 361: A first electrostatic trapping field is formed between the surface of the multi-aperture arrangement 350 and the first trapping electrode 361, and charged interfering particles 702, 703 move from the surface of the multi-aperture arrangement 350 towards the first trapping electrode 361. The same applies to the transfer of a charged interfering particle 701 from the electrostatic shielding element 372 to the first trapping electrode 361.

[0132] Fig. Figure 10a shows the situation after the potential at the second trapping electrode 362 has also been changed and a second electrostatic trapping field has been established between the second trapping electrode 362 and the first trapping electrode 361. This second electrostatic trapping field is stronger than the first electrostatic trapping field, so that charged interfering particles 701, 702, 703 migrate from the first trapping electrode 361 to the second trapping electrode 362. Fig. Figure 10b shows the end of this migration process: All charged interfering particles 701, 702, 703 are now located at the second capture electrode 362, which also serves as a storage capture electrode. After the transfer of the charged interfering particles 701, 702, 703 to the second capture electrode 362 is complete, the potential at the first capture electrode 361 can be changed and, in particular, switched off or set to ground potential. This is the simplest implementation. However, the potential at the first capture electrode 361 can also be reduced in magnitude while maintaining its sign, or the potential can be reversed. Of course, it is also possible to provide one or more capture electrodes above the multi-aperture arrangement 350, which have a larger diameter D than the capture electrodes 361, 362 and are thus located further away from the particle-optical axis Z.

[0133] Fig. Figure 11 schematically shows another embodiment of the invention. In principle, it depicts an extension of the multi-aperture arrangement 350 from the Fig. 8, Fig. 9 and Fig. 10: At the in Fig. In the embodiment shown in Figure 11, three further trapping electrodes 363, 364, and 365 are arranged below the multi-aperture arrangement 350 with respect to the particle-optical beam path. The control unit 10 of the multi-particle beam system 1 is configured to also control these further trapping electrodes 363, 364, and 365 and to provide each of them with an individually adjustable potential. These trapping electrodes 363, 364, and 365 serve to capture or store charged interfering particles 704, 705, and 706 located on the underside of the multi-aperture arrangement 350.Before the charged interfering particles 704, 705, and 706 are transferred to the capture electrodes 363, 364, and 365 in decontamination mode, as described in several previous sections, they can be irradiated from the underside of the multi-aperture arrangement 350 to selectively charge them. For this purpose, the multi-particle beam system 1 has a retractable beam stop 390 in the lower region of the multi-beam generator vacuum chamber 380 within the particle-optical beam path. This beam stop 390 is designed to backscatter charged particles, especially electrons, that strike it, so that charged particles backscattered from the beam stop 390 can irradiate the multi-aperture arrangement 350 from the rear. This is indicated by arrows 313, which emanate from beam stop 390. Furthermore, it is not only primarily backscattered particles or...Electrons can be used for charging, but also secondarily backscattered particles or electrons. This is shown by arrows 314 in . Fig. 11 is indicated, while the primarily backscattered particles are indicated by arrows 313. Overall, this irradiation process within the multi-beam generator vacuum chamber 380 results in the appearance of many charged particles or electrons, so that any interfering particles 704, 705, 706 that may be present can be comprehensively charged. This affects, on the one hand, the back side of the multi-aperture arrangement 350, but possibly also wall areas of the multi-beam generator vacuum chamber 380.

[0134] The source for the irradiation process can be identical to the particle source 301 of the multiplicity particle beam system. For example, it is possible to operate the particle source 301 in a normal operating mode and in a flooding mode, whereby the particle source 301 emits fewer charged particles and / or charged particles with lower energy, such as electrons, than in the normal operating mode. This is also possible with the particle beam 312 in Fig. 11 as indicated. Alternatively, it is possible that the multi-particle beam system is equipped with another particle source, such as a flood gun, which is controlled by the controller 10 to irradiate the multi-aperture arrangement 350 in decontamination mode. The flood gun can, for example, be located in the multi-beam generator vacuum chamber 380 (not shown).

[0135] Additionally or alternatively, it is also possible to arrange a UV source and / or an X-ray source for irradiating the multi-aperture arrangement within the multi-beam generator vacuum chamber 380 (neither shown). The basic idea here is that charged particles are also generated during these irradiation processes via scattering and secondary processes, which then traverse the interior of the multi-beam generator vacuum chamber 380 and enable the charging of interfering particles 704, 705, 706. When using an X-ray source for irradiation, a low-energy X-ray source, for example with energies around 100 eV, is preferred in order to avoid damaging the multi-aperture arrangement with X-rays. Furthermore, the exposure time of the multi-aperture arrangement with low-energy X-rays is short, which also minimizes potential residual damage to the multi-aperture arrangement.

[0136] Of course, it is possible that interfering particles 701, 702 can occur not only on a first plate of the multi-aperture arrangement and on a last plate of the multi-aperture arrangement 350, but that they can also occur within the apertures of the multi-aperture arrangement 350. A corresponding example is given in Fig. Figure 12 shows the multi-aperture arrangement 350. In the example shown, the arrangement comprises a first multi-aperture plate 304 and a final multi-aperture plate 306.2. A further multi-aperture plate 306.1 is arranged between them, with ring electrodes provided around each aperture. These ring electrodes 82 can be individually energized during normal operation of the multi-particle beam system 1. The actual plate 306.1, in contrast, is at a different potential, for example, ground potential. In the example shown, the first multi-aperture plate 304 is also the filter plate and is electrically conductive. The final multi-aperture plate 306.2 is also electrically conductive in the example shown. It is therefore possible to selectively apply a first or final voltage to the first multi-aperture plate 304 and the final multi-aperture plate 306.2, respectively, using the control unit 10 (not shown).To provide a second suction potential, where the first and second suction potentials are different. In the example shown, the first multi-aperture plate 304 has a potential of -100 V, and the final multi-aperture plate 306.2 has a potential of +100 V. The multi-aperture plate 306.1, located between these two plates, is at ground potential. These potentials provide a suction potential, allowing charged contaminant particles 701, 702 to be drawn out of the interior of the multi-aperture arrangement 350 due to the applied electrostatic field. In the case of negatively charged contaminant particles 701, 702, these initially migrate to the final multi-aperture plate 306.2 and from there, during the described decontamination process, first to the first capture electrode 307, which in the example shown is identical to a counter electrode 307 in normal operating mode.Charged interfering particles 701, 702 can then be successively transferred to the second trapping electrode 362, then to the third trapping electrode 363, and finally to the fourth trapping electrode 364. In normal operating mode, preferably only the fourth trapping electrode 364 is switched on. Due to its position at the same level as the second trapping electrode 362 and the ring-shaped design of all trapping electrodes 362, 363, 364, the electrostatic field of the fourth trapping electrode 364 is shielded during normal operation.

[0137] Furthermore, in Fig. Figure 12 illustrates that the movable beam stop 390 also allows charging with charged particles inside the multi-aperture arrangement 350: By flooding the area around the multi-aperture arrangement 350, the backscattered particles can be used to charge perturbing particles 701, 702 and 703 on the particle tracks 313.1, 313.2 and 313.3.

[0138] In the illustrated embodiments, the profiles of the trapping electrodes 361, 362, 363, 364, 365 are either circular or elliptical. However, it is also possible to explicitly choose a non-circular and non-elliptical profile for the trapping electrodes. This allows the shape and strength of the electrostatic springs of the trapping electrodes 361, 362, 363, 364, 365 to be specifically influenced.

[0139] Fig. Figure 13 schematically illustrates the removal of charged perturbation particles 701 from a surface 352 of a multi-aperture arrangement 350 by means of an alternating electric field. Fig. Figure 13a shows the situation at the beginning of the dissolving process: A perturbation particle 701 is negatively charged and rests with its long side on the surface 352 of the multi-aperture arrangement 350. The contact area is therefore large. Van der Waals forces between the charged perturbation particle 701 and the surface 352 are therefore also large. By providing an alternating electric field EA, which in Fig. As shown in Figure 13a by the double arrow, it is possible to reduce the contact area between the interfering particle 701 and the surface 352: For this purpose, an alternating electric field is generated near the surface of the multi-aperture arrangement 350, which is oriented parallel to the surface of the multi-aperture arrangement 350. In contrast, an electrostatic trapping field ED is non-alternating and directed away from the surface 352.

[0140] In Fig. Figure 13b shows the effect of the alternating electric field EA after some time: Due to the shaking of the charged interfering particle 701, the interfering particle 701 has stood upright and its contact area with the surface 352 of the multi-aperture arrangement 350 has been reduced. Thus, the frictional forces, the van der Waals forces, between the charged interfering particle 701 and the multi-aperture arrangement 350 are also reduced, so that by a suitably selected electrostatic capture field ED the charged interfering particle 701 can ultimately be removed from the surface 352 of the multi-aperture arrangement 350.

[0141] Fig. Figure 14 schematically shows another implementation for the facilitated removal of a disruptive particle 701 from a surface of the multi-aperture arrangement 350 or, more generally, from the multi-aperture arrangement 350: In Fig. In the example shown, a multi-aperture arrangement 350 is tongue-shaped. This means that a support 386 is provided only on one side of the multi-aperture arrangement 350. The end of the multi-aperture arrangement 350 opposite the support 386 is, in principle, freely movable and can oscillate. To detach charged interfering particles, a vibration generator 385 is arranged at the free end of the tongue of the multi-aperture arrangement 350 in the example shown. The control unit 10 (not shown) is configured to control the vibration generator 385 in decontamination mode and thus set the multi-aperture arrangement 350 into vibration. In this way, charged interfering particles 701 adhering to the multi-aperture arrangement 350 are also shaken and can therefore be detached from the multi-aperture arrangement 350 in a decontamination mode of the multi-particle beam system 1. The vibration generator 385 can provide mechanical vibrations and / or sound vibrations.

[0142] A multi-particle beam system 1 according to the invention preferably operates in normal operating mode in a high vacuum, i.e. in a pressure range of 10 -9mbar or better. Nevertheless, it has been found that charged interfering particles 701 can pose a problem in this type of multi-particle beam system 1. To eliminate this problem, various measures for decontamination of the multi-beam generator vacuum chamber 380 or the multi-aperture arrangement 350 have been described above. However, another idea is to prevent interfering particles from entering the multi-beam generator vacuum chamber 380 in the first place, or at least to further reduce their number through additional measures. Although pumps suitable for generating a high vacuum often have the specification "non-particle-forming," it seems that corresponding interfering particles are still repeatedly present in the vicinity of pumps. It therefore appears insufficient to rely entirely on the particle traps inherent in the pumps.Therefore, a further or alternative approach of the invention is to further develop a pump line system 900 for a multiple particle beam system 1:. According to this embodiment, a multi-particle beam system 1 further comprises a pumping system with at least one vacuum pump 901, 902, which is connected to the multi-beam generator vacuum chamber 380 by means of a pumping line system 390. A particle trap 910 for capturing charged interfering particles is arranged within the pumping line system 900. It should be emphasized again that this particle trap 910 is arranged independently of, or outside of, the pumps 901 and 902. This therefore truly represents an improvement of the pumping line system 900.

[0143] Fig. Figure 15 schematically shows a pump line system 900 of a multi-particle beam system 1 with a particle trap 910: The pump line system 900 branches out after exiting the multi-beam generator vacuum chamber. One branch leads to the ion getter pump 901, and another branch leads to the turbopump 902. Furthermore, a potential source of interfering particles, such as a chamber 903, is arranged in the pump line system 900. This chamber may, for example, be used for storing or preserving a sample for the multi-particle beam system. A vent valve 904 is arranged between the chamber 903 and the multi-beam generator vacuum chamber 380. Vent valves are not normally explicitly classified as "non-particle-forming." Therefore, a vent valve 904 represents a potential source of interfering particles.

[0144] In the Fig. In the embodiment shown in Figure 15, a particle trap 910 is now arranged directly in front of the entrance to the multi-beam generator vacuum chamber 380. This is intended to prevent charged interfering particles 701 from entering the multi-beam generator vacuum chamber 380 during a ventilation process.

[0145] The particle trap itself can be implemented in different ways. Fig. Figure 16 schematically shows a particle trap 910 in two different versions. Fig. 16 The patterned hatched background is due to the fact that the particle trap 910 is located within the pumping system 900. Fig. Figure 16a shows an embodiment of a particle trap 910 with a capacitor 911a, 911b and a flood gun 912, which is configured to emit charged particles 3, in particular electrons. This emission is indicated by the circular elements with the minus sign in the center; the arrow indicates the direction of motion of the electrons emitted by the flood gun 912. If a disturbance particle 701, which is initially uncharged, passes the flood gun 912 or the particle jet emitted by it, the disturbance particle 701 becomes negatively charged in the example shown. If it then moves into the electrostatic field of the capacitor with the two plates 911a, 911b, the charged disturbance particle 701 is deposited on the positively charged capacitor plate 911b. The charged disturbance particle 701 is thus trapped there.Both the flood cannon 912 and the condenser 911a, 911b can be controlled by the control unit 10 during a ventilation process of the multi-jet generator vacuum chamber 380.

[0146] Fig. Figure 16b shows an alternative embodiment of a particle trap 910 with a first capacitor 913a, 913b and a second capacitor 911a, 911b. In the direction of ventilation of a gas stream for ventilating the multi-jet generator vacuum chamber 380, the first capacitor 913a, 913b is arranged upstream of the second capacitor 911a, 911b. During the ventilation process, an alternating electric field is applied to the first capacitor 913a, 913b by means of the control system, which causes a charge to be generated by a foreign particle 701 passing through this field. After passing through the alternating electric field, the now charged foreign particle 701 can again be trapped by a non-alternating electrostatic field of the second capacitor 911a, 911b and is deposited on one of the plates, here 911b.

[0147] It should be noted that the design of the two capacitors 911 and 913 as plate capacitors is only an example. The design could also be implemented as cylindrical capacitors or in another way.

[0148] In both versions according to Fig. The control unit 10 of the multi-particle beam system is configured to limit the gas flow through the pump line system 900 during a critical time interval of the aeration and / or venting process and thus to activate the particle trap 910 during this critical time interval. The critical time interval preferably corresponds to the time interval in which the pressure in the pump line system is greater than or equal to 1 mbar during aeration. At lower gas or air flow rates, it is unlikely that interfering particles 701 will be moved by this gas or air flow. Therefore, it is possible to limit the active time of the particle trap 910 to a specific, critical time interval.

[0149] It should be emphasized that the particle trap 910 is to be used in the pumping system 900 in connection with the invention described above, in which a multiple particle beam system 1 is operated in a decontamination mode on the one hand and in a normal operating mode on the other. However, it is also possible to provide a particle trap in a pumping system 900 for a different multiple particle beam system.

[0150] Fig. Figure 17 schematically shows an alternative arrangement of particle traps 910 in a pumping system 900. Unlike the example according to Fig. In section 15, a particle trap 910 is not arranged directly in front of the entrance to the multi-beam generator vacuum chamber 380, but rather particle traps 910 are arranged directly after an outlet of a vacuum chamber 901 and directly after an outlet of a potential source of interfering particles, such as the valve 904. Other arrangements of particle traps 910 are also possible. Furthermore, these particle traps 910 can be designed in different ways, as is the case, for example, in connection with Fig. 16 has already been described.

[0151] The following describes a further embodiment of the invention, which makes it possible to capture and retain interfering particles or charged interfering particles in a particularly simple manner. Unlike the solutions described with capture electrodes, this solution is passive. For capturing and retaining interfering particles, and in particular charged interfering particles 701, a trapping trench system with at least one trapping trench for capturing charged interfering particles 701 is provided.

[0152] Fig. Figure 18 schematically illustrates an exemplary embodiment of this aspect of the invention: Specifically, it shows Fig. Figure 18 schematically shows a multi-aperture arrangement 350 in a top view. The first multi-aperture plate 304 is shown in the particle-optical beam path. This first multi-aperture plate is normally identical to the so-called filter plate, and the first single-particle beams of a multi-particle beam system are only formed upon striking or passing through this multi-aperture plate 304 with its multitude of apertures. In the example shown, the first multi-aperture plate 304 has a multi-aperture region with a multitude of apertures, which are arranged in Fig. 18 are only schematically indicated as a pattern fill in the form of the dotted area. The arrangement of the multitude of apertures in the multi-aperture area 355 can be designed differently; for example, hexagonal arrangements of apertures can be provided. However, it is also possible to provide rectangular grids or an overall circular arrangement of apertures in the multi-aperture area. In addition to this multi-aperture area 355, the first multi-aperture plate 304 includes an outer area 356, which is arranged around the multi-aperture area 355. In this outer area 356, a trap trench system with at least one trap trench is provided. In the example shown, the trap trench system comprises three trap trenches 381, 382, ​​and 383, which are essentially formed around the multi-aperture area 356. In the example shown, each of the trap trenches 381, 382, ​​and 383 has four interruptions, each of which is arranged in corner areas.The interceptor trenches 381, 382, ​​383 are formed linearly in sections. For example, interceptor trench 381, which forms the innermost interceptor trench, comprises interceptor trench sections 381.1, 381.2, 381.3, and 381.4. It is also possible to form a continuous interceptor trench 381, 382, ​​and 383 without any interruptions, but this may be more difficult to manufacture than constructing an interceptor trench 381, 382, ​​383 with multiple interruptions, and especially the linear construction of interceptor trench sections in sections. An interceptor trench 381, 382, ​​383, or an interceptor trench section, can be produced very simply using etching techniques. Isotropic or anisotropic etching processes can be used.

[0153] A trapping trench system 381, 382, ​​383 is suitable for reducing or stopping the migration or movement of interfering particles 701 on the surface of the multi-aperture arrangement 350. This is based on the principle that, when interfering particles 701 migrate through a trapping trench system 381, 382, ​​383, potential energy and kinetic energy are repeatedly converted into one another, resulting in an overall energy loss due to friction. This continuously reduces the mobility or movement of the interfering particles 701 until it eventually comes to a complete standstill. Furthermore, a trapping trench system 381, 382, ​​383 increases the surface area to which interfering particles can adhere or be deposited compared to a flat surface of the multi-aperture plate 304, leading to increased interaction between the interfering particles and the first multi-aperture plate.the trench surface, so that Van der Waals forces between perturbation particles on the one hand and the trench or the first multi-aperture plate 304 on the other hand are increased, which is why the momentum of perturbation particles is further reduced.

[0154] The number of interceptor ditches 381, 382, ​​383 in the interceptor ditch system can vary. Generally, providing several interceptor ditches 381, 382, ​​383 is preferable to providing only a single interceptor ditch 381. However, it is possible that only a single interceptor ditch 381 is provided.

[0155] In general, it is advantageous to provide a sequence of trap trenches 381, 382, ​​383, with this sequence extending outwards from the multi-aperture area 355. Viewed in this way, trap trench 381 forms in Fig. 18 is the innermost trap trench, trap trench 382 forms a second trap trench located further outwards, and trap trench 383 forms the outermost trap trench in the example shown. It is also possible to provide further trap trenches, located even further outwards.

[0156] It is possible to choose an identical cross-sectional shape for all interceptor trenches 381, 382, ​​and 383, or to choose different shapes for each trench. Choosing an identical cross-sectional shape is preferred, as this simplifies the construction of the interceptor trench system with interceptor trenches 381, 382, ​​and 383.

[0157] Besides the shape of the cross-section itself, the dimensions of the cross-sections can also be identical or different between different trenches 381, 382, ​​383. The following figures show several exemplary embodiments:

[0158] Fig. Figure 19 schematically shows intercepting trenches 381, 382, ​​383 and 384 in a sectional view. The section shown begins at the multi-aperture area 355 (left side in Fig. 19) away from the multi-aperture area 355 (right side in Fig. 19).

[0159] In Fig. 19a All four interceptor trenches 381, 382, ​​383, and 384 have the same cross-sectional shape, which is that of a rectangle. However, the specific dimensions of the respective cross-sections of the interceptor trenches 381, 382, ​​383, and 384 differ in pairs: the depth t of the innermost interceptor trench 381 is the greatest, and the depth t decreases successively from the inside out. The depth t could also increase successively. The width b of all interceptor trenches 381, 382, ​​383, and 384 remains constant in this embodiment of the invention, but it could also vary. The distance a between adjacent interceptor trenches 381, 382, ​​383, and 384 does not vary in this embodiment but remains constant, although it could also vary.

[0160] In the Fig. In the example shown in Figure 19b, not only is the shape of the respective cross-sections of all intercepting trenches 381, 382, ​​383, 384 identical, namely always rectangular, but the width b of the intercepting trenches 381, 382, ​​383, 384 is also always the same, although it could also vary. The same applies to the distance a between adjacent intercepting trenches 381, 382, ​​383, 384, which does not vary from the inside to the outside. However, this could also be different.

[0161] The in Fig. The embodiments of the invention shown in Figure 19 can be produced using anisotropic etching processes. Fig. Figure 20 schematically shows another embodiment of several intercepting trenches 381, 382, ​​383, 384 in a sectional view: A section is again shown starting near the multi-aperture area 355 (left side in Fig. 20), which then continues outwards (right side in Fig. 20). Unlike in the example of Fig. 19 is a cross-sectional shape of the intercepting trenches 381, 382, ​​383, 384, essentially triangular. In the example according to Fig. 20a the depth t of the trenches 381, 382, ​​383, 384 varies, while the depth t in the example according to Fig. 20b remains constant. In the example shown, the widths of the trenches b and the distance a between adjacent intercepting trenches 381, 382, ​​383, 384 are also kept constant. However, this could also be achieved differently. These cross-sectional shapes and dimensions of intercepting trenches 381, 382, ​​383, 384 can also be produced using isotropic etching processes.

[0162] Fig. Figure 21 schematically shows another embodiment of intercepting trenches 381, 382, ​​383, 384 in a sectional view: the shape of a cross-section of the intercepting trenches 381, 382, ​​383, 384 is, in the example shown, circular or essentially corresponds to a segment of a circle. Such a shape of intercepting trenches 381, 382, ​​383, 384 can be generated by means of isotropic etching processes. Fig. 21a Not only the shape, but also the dimensions of the trenches 381, 382, ​​383, 384 are identical, but they could also vary. In Fig. In contrast, in 21b, although the cross-sectional shapes are identical, the dimensions vary: Both the depth t and the maximum width b of the intercepting trenches 381, 382, ​​383, 384 decrease from left to right, that is, in the example shown, from the multi-aperture area 355 outwards. The distance a between adjacent trenches on the opening side can vary or be kept constant.

[0163] Fig. Figure 22 schematically shows a first multi-aperture plate or filter plate 304 in a sectional view. According to this embodiment, a central trench 387 is provided in the multi-aperture plate 304, with the entire multi-aperture area 355 arranged in this central trench 387. The outer area 356 of the first multi-aperture plate 304 is not located in the central trench 387. Similarly, the intercepting trenches 381, 382, ​​which are located in the outer area 356, are also not located in the central trench 387. In the illustrated embodiment, the respective trench depth t of the sequence of intercepting trenches 381, 382, ​​which are located in the outer area 356, increases from the inside out. The innermost trench 381 has a depth t1 that is less than the depth t2 of the outermost trap trench 382. In the example shown, both trap trenches 381 and 382 are also less deep than the central trap trench 387.

[0164] The specific sequence of trenches 381, 382 or other trenches (In Fig. 22 (not shown) in combination with the central trap 387 ensures better overall stability of the first multi-aperture plate 304.

[0165] The central trench 387 results in many first multi-aperture plates 304 or filter plates 304 due to the manufacturing process for multi-aperture plates: MEMS techniques and planar integration techniques are used for their production, in which a central trench 387 results almost automatically. The entire surface of the first multi-aperture plate 304 with the central trench 387 and the trench system with the intercepting trenches 381, 382 can be provided with a conductive layer, in particular a metallic layer. When this layer 99 is grounded, this ensures that particles, and especially electrons, striking the filter plate 304 during the formation of the first single-particle beams 3 can be absorbed and dissipated there.

[0166] According to one embodiment, the following relationship applies to a depth t of the central trench: 10µm ≤ t ≤ 200µm. However, it is also possible not to provide a central trench at all.

[0167] According to a preferred embodiment, the following relationship applies to the trench depth t of a trap 381, 382, ​​383, 384: 10 µm ≤ t ≤ 180 µm. Additionally or alternatively, the following relationship can apply to the maximum trench width b of a trap 381, 382, ​​383, 384: 8 µm ≤ b ≤ 200 µm, in particular 8 µm ≤ b ≤ 20 µm or 8 µm ≤ b ≤ 18 µm. Additionally or alternatively, the following relationship can apply to the distance a between adjacent trap 381, 382, ​​383, 384: b / a ≥ 1.5, preferably b / a ≥ 2.0. However, it is also possible that the ratio b / a is significantly larger than 2.0; this depends in particular on the cross-sectional shape of the trench cross-sections. The distance a between adjacent intercepting trenches is measured at the surface of the multi-aperture plate and, in particular, the filter plate 304.The maximum trench width b is measured at the widest point of the interceptor trench, which can be located at any position within the interceptor trench 381, 382, ​​383, 384, depending on the cross-sectional shape of the interceptor trench 381, 382, ​​383, 384. It is important, of course, that adjacent interceptor trenches 381, 382, ​​383, 384 maintain a minimum distance from each other to prevent an unintended breach between them. In the case of... Fig. 19 and Fig. For the 21 design variants shown, the following minimum distance Ma can apply, for example: 20 µm ≤ Ma ≤ 40 µm. In the case of the Fig. In contrast, in the 20 shown design variants, the minimum distance Ma corresponds to the distance a and can, in principle, be chosen to be arbitrarily small.

[0168] Fig.Figure 23 schematically shows a multi-aperture arrangement 350 of a multi-particle beam system 1 with a preceding pre-aperture 379 and a subsequent exit aperture 378. The pre-aperture 379 truncates a widened particle beam before it strikes the multi-aperture arrangement 350. This pre-aperture 379 is designed in a stepped manner with exactly one step. The step can represent an additional mechanical barrier for interfering particles on the way to the multi-aperture arrangement 350, which approach the multi-aperture arrangement 350 from the particle source side. In the example shown, an exit aperture 378 is also provided downstream of the multi-aperture arrangement 350, which is designed in a stepped manner with exactly one step. This step can, in turn, represent an additional mechanical barrier for interfering particles on the way to the multi-aperture arrangement 350, which approach the multi-aperture arrangement 350 from the object side.

[0169] The embodiments of the invention described with reference to the figures are merely exemplary and are not to be understood as limiting the invention.

[0170] It is possible to combine the described embodiments in whole or in part, provided that no technical contradictions result.

[0171] A multi-particle beam system and a method for operating it in a decontamination mode are disclosed, in which charged interfering particles located in a sensitive area of ​​a multi-aperture arrangement are captured and removed from the sensitive area. Electrostatic capture electrodes are arranged and controlled in a specific manner, and / or a trench trapping system is used to capture the charged interfering particles. The charged interfering particles are stored during the normal operating mode of the multi-particle beam system in such a way that they do not interfere with normal operation. Reference symbol list 1. Multi-beam particle system, multi-beam particle microscope 3 primary particle beams, first single-particle beams 5 beam spots, points of impact 7. Object, sample, wafer 9 secondary particle beams, second single-particle beams 10 Computer system, control 15 Sample surface, wafer surface 25 pixels of a second single-particle beam 81 Multipole electrode 82 Ring electrode 83 spacers 84 Ring electrode 85 aperture 86 spacers 99 Absorbing and conductive layer 101 Object level 102 lens 103 Field lens 105 axle 108 Beam crossing, Cross-over 200 detector system 205 Projection lens system 206 Projection lens 207 Multi-particle detector 208 Projection lens 210 Projection lens 212 Beam crossing, Cross-over 214 aperture filter, contrast diaphragm 222 Collective Anti-Deflection System 300 beam generating device 301 Particle source 302 Extractor 303 Collimation lens system, condenser lens system 304 multi-aperture plate, filter plate 305 Multibeam Particle Generator 306 Multi-aperture plate 307 Field lens, aperture plate, counter electrode 308 Field lens 309 Particle beam 310 Multi-aperture plate 311 Illuminating particle beam 312 Particle beam (flood mode) 313 backscattered electrons 314 backscattered electrons 321 Intermediate image plane 323 beam foci 333 Stopping area 335 Membrane area 350 Multi-aperture arrangement 351 Aperture 352 multi-aperture plate, multi-aperture arrangement 353 Multideflector array 355 Multi-aperture range 356 Outdoor area 361 Capture electrode 362 Capture electrode 363 Capture electrode 364 Capture electrode 365 Catching electrode 370 shielding 371 Nozzle 372 Shielding element, shielding ring 378 Exit aperture 379 Preaps 380 Multi-beam generator vacuum chamber 381 trench 382 trenches 383 trenches 384 trenches 385 vibration generators 386 bracket 387 central trench 390 sliding jet stop 398 Pre-counter electrode 399 Electrode, Earth potential 400 beam switch, magnetic arrangement 500 scan deflectors 600 Moving table or positioning device 701 interfering particles 702 interfering particles 703 interfering particles 704 disruptive particles 900 Pumping system 901 Ion getter pump 902 Turbo pump 903 Interference particle source, chamber 904 Ventilation valve 910 particle trap 911 Capacitor 912 Flooding cannon 913 Capacitor (alternating electric field) x direction y direction z direction Z particle optical axis EA alternating electric field ED non-alternating electric field t trench depth b maximum trench width a distance between adjacent trenches on the opening side E1 Intermediate image plane E2 Object level QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] US 7 244 949 B2

[0004] US 2019 / 0355544 A1

[0004] US 10,861,666 B1 [0012, 0013] WO 2005 / 024881 A2

[0099] WO 2007 / 028595 A2

[0099] WO 2007 / 028596 A1

[0099] WO 2011 / 124352 A1

[0099] WO 2007 / 060017 A2

[0099] DE 10 2013 016 113 A1

[0099] DE 10 2013 014 976 A1

[0099]

Claims

[1] Method for operating a multiple particle beam system comprising the following steps: Providing a multi-particle beam system with a multi-aperture arrangement and with at least two capture electrodes, wherein the multi-aperture arrangement comprises a plurality of multi-aperture plates, each of the multi-aperture plates comprising a multi-aperture region with a plurality of apertures and an exterior area around the multi-aperture region, wherein the plurality of apertures in a normal operating mode of the plurality-particle beam system is penetrated by a plurality of charged single-particle beams, wherein a first trapping electrode is arranged around the particle-optical axis Z of the multi-particle beam system and projected along the direction of the particle-optical axis onto the multi-aperture arrangement in its outer area, wherein a second trapping electrode is arranged circumferentially around the particle-optical axis Z of the multi-particle beam system and projected along the direction of the particle-optical axis onto the multi-aperture arrangement in its outer area, and wherein the second trapping electrode is positioned further away from the particle-optical axis than the first trapping electrode; Operating the multi-particle beam system in a decontamination mode in which charged interfering particles are trapped in a sensitive region of the multi-aperture arrangement, wherein the decontamination mode comprises the following steps (a) to (c) in the specified order: (a) Providing the same potential at the multi-aperture arrangement, at the first trapping electrode and at the second trapping electrode; (b) Changing the potential at the first trapping electrode and generating a first electrostatic trapping field between the first trapping electrode and the multi-aperture arrangement, so that charged interfering particles can migrate from the multi-aperture arrangement to the first trapping electrode; and (c) Changing the potential at the second trapping electrode and generating a second electrostatic trapping field between the second trapping electrode and the first trapping electrode, wherein the second electrostatic trapping field is stronger than the first electrostatic trapping field, so that charged interfering particles can migrate from the first trapping electrode to the second trapping electrode; and Operating the multi-particle beam system in a normal operating mode in which the multi-aperture arrangement is permeated by the multitude of charged single-particle beams, wherein in normal operating mode the same potential is provided at the multi-aperture arrangement and at the first trapping electrode and wherein a different potential is provided at one of the other trapping electrodes than at the multi-aperture arrangement, so that in normal operating mode the charged interfering particles remain at this trapping electrode, which is a storage trapping electrode. [2] Method according to claim 1, where more than two capture electrodes are provided, and in normal operating mode, a different potential is provided at exactly one of the trapping electrodes than at the multi-aperture arrangement. [3] Method according to claim 2, wherein the exactly one trapping electrode at which a different potential than at the multi-aperture arrangement is provided is the trapping electrode that is located furthest outwards with respect to the particle-optical axis of the multiple particle beam system. [4] Method according to one of the preceding claims, wherein in the decontamination mode after step (c) the following step is further carried out: (d) Changing the potential at the first trapping electrode, without changing the direction of the second electrostatic trapping field. [5] Method according to claim 4, wherein the potential at the first trapping electrode is reduced in magnitude while maintaining its sign. [6] Method according to claim 4, wherein the potential at the first trapping electrode is set to earth potential. [7] Method according to claim 4, wherein the potential at the first trapping electrode is reversed. [8] Method according to one of the preceding claims, wherein a third trapping electrode is provided, which is arranged circumferentially around the particle-optical axis Z of the multi-particle beam system and projected along the direction of the particle-optical axis onto the multi-aperture arrangement in its outer area, wherein the third trapping electrode is arranged further away from the particle-optical axis Z than the second trapping electrode, and where, after step (c) and in particular after the optional step (d) in the decontamination mode, the following step is further executed: (e) Changing the potential at the third trapping electrode and generating a third electrostatic trapping field between the third trapping electrode and the second trapping electrode, wherein the third electrostatic trapping field is stronger than the second electrostatic trapping field, so that charged interfering particles can migrate from the second trapping electrode to the third trapping electrode. [9] Method according to the preceding claim, wherein in the decontamination mode after step (e) the following step is further carried out: (f) Changing the potential at the second trapping electrode, without changing the direction of the third electrostatic trapping field. [10] Method according to one of the preceding claims, wherein in normal operating mode the electrostatic field of the storage-capture electrode is shielded so that it does not interfere with the beam shaping. [11] Method according to one of the preceding claims, wherein at least one of the trapping electrodes is not used for beam shaping in the normal operating mode of the multiple particle beam system. [12] Method according to one of the preceding claims, wherein at least one of the trapping electrodes is used as a trapping electrode in decontamination mode and for beam shaping in normal operating mode of the multi-particle beam system. [13] Method according to any of the preceding claims, wherein a plurality of trapping electrodes, arranged circumferentially around the particle-optical axis, are provided both above and below the multi-aperture arrangement with respect to the particle-optical beam path, and wherein the process steps (a) to (c) are carried out using the respective capture electrodes both above and below the multi-aperture arrangement. [14] Method according to one of the preceding claims, wherein in decontamination mode a first suction potential is provided at an upper multi-aperture plate of the multi-aperture arrangement and wherein a second suction potential is provided at a lower multi-aperture plate of the multi-aperture arrangement, wherein the first suction potential and the second suction potential are different, so that charged interfering particles can be sucked out of the interior of the multi-aperture arrangement between the upper multi-aperture plate and the lower multi-aperture plate due to the applied electrostatic field. [15] Method according to one of the preceding claims, wherein in decontamination mode and in particular before step (a) the following step is further carried out: (g) Irradiation of the multi-aperture arrangement for electrostatic charging of interfering particles. [16] Method according to the preceding claim, wherein the multi-aperture arrangement is irradiated both on the source side and on the object side with respect to the particle-optical beam path. [17] Method according to the preceding claim, further comprising the following step: (h) Inserting a beam stop into the particle-optical beam path below the multi-aperture arrangement, so that when the beam stop is irradiated through the multi-aperture arrangement, the irradiating charged particles are backscattered and thereby irradiate the multi-aperture arrangement on the object side. [18] A method according to one of the preceding claims, further comprising, in decontamination mode and in particular after steps (g) and (h), the following step: (i) Providing vibrations to the multi-aperture arrangement. [19] Method according to the preceding claim, wherein the vibrations provided comprise mechanical vibrations. [20] Method according to any one of claims 18 to 19, wherein the vibrations provided comprise sound vibrations and / or ultrasonic vibrations. [21] A method according to one of the preceding claims, further comprising, in decontamination mode and in particular after steps (g) and (h), the following step: (j) Providing an alternating electric field near the surface of the multi-aperture arrangement, wherein the direction of the electrostatic field is oriented parallel to one of the surfaces of the multi-aperture arrangement. [22] Multi-beam particle beam system, in particular multi-beam particle microscope, comprising the following: a multi-beam generator with a multi-aperture arrangement, wherein the multi-aperture arrangement comprises a plurality of multi-aperture plates, each of the multi-aperture plates comprising a multi-aperture region with a plurality of apertures and an exterior area around the multi-aperture region, wherein the plurality of apertures in a normal operating mode of the plurality-particle beam system is penetrated by a plurality of charged single-particle beams, a first capture electrode, which is arranged around the particle-optical axis Z of the multi-particle beam system and projected along the direction of the particle-optical axis onto the multi-aperture arrangement in its outer area; a second capture electrode, which is arranged around the particle-optical axis Z of the multi-particle beam system and projected along the direction of the particle-optical axis onto the multi-aperture arrangement in its outer area, a mode selection device to operate the multi-particle beam system in normal operating mode or in a decontamination mode, wherein, in the decontamination mode, charged interfering particles from a sensitive area of ​​the multi-aperture arrangement encompassing the multi-aperture area are captured by means of the capture electrodes; and a control system for controlling the multiple particle beam system; wherein the control is set up to provide an adjustable potential at the first trapping electrode, to provide an adjustable potential at the second trapping electrode and to provide a potential, in particular earth potential, at the multi-aperture arrangement. [23] A multi-particle beam system according to claim 22, further comprising: an electrostatic shielding element that is located on a surface of the multi-aperture arrangement and projecting from that surface, and is arranged circumferentially around the multi-aperture area of ​​the multi-aperture arrangement; and wherein the second trapping electrode and the electrostatic shielding element are arranged at the same height with respect to the particle-optical beam path, so that the electrostatic shielding element can shield an electrostatic field of the second shielding electrode in the normal operating mode, wherein the first trapping electrode is arranged above the second trapping electrode and above the electrostatic shielding element with respect to the particle-optical beam path, and wherein the control system is configured to provide the same potential, and in particular ground potential, at the multi-aperture arrangement and at the electrostatic shielding element. [24] Multi-particle beam system according to claim 23, wherein the first trapping electrode is positioned closer to the particle-optical axis than the second trapping electrode; and / or wherein the first trapping electrode is positioned further away from the particle-optical axis than the electrostatic shielding element. [25] Multi-particle beam system according to one of claims 23 to 24, wherein the shielding element has a shielding ring whose profile is substantially triangular. [26] Multi-particle beam system according to one of claims 22 to 25, wherein the multi-beam generator is arranged in a multi-beam generator vacuum chamber, into which an evacuable beam tube opens on the particle source side, in which charged particles are guided. [27] Multi-particle beam system according to the preceding claim, wherein the first trapping electrode and the second trapping electrode are arranged such that they are retracted laterally behind an imaginary extension of the beam tube towards the multi-aperture arrangement. [28] A multi-particle beam system according to one of claims 23 to 27, comprising at least two further trapping electrodes arranged around the particle-optical axis Z of the multi-particle beam system and projected along the direction of the particle-optical axis onto the multi-aperture arrangement in its outer area and arranged below the multi-aperture arrangement with respect to the particle-optical beam path, wherein the control system is configured to control the further trapping electrodes and to provide an individually adjustable potential at each of the trapping electrodes. [29] A multi-particle beam system according to any one of claims 22 to 28, wherein the profile of one of the capture electrodes is non-circular and non-elliptical. [30] Multi-particle beam system according to any one of claims 22 to 29, which furthermore features a flood gun for irradiating the multi-aperture arrangement, and the control system is set up to operate the flood gun in decontamination mode for irradiation of the multi-aperture array. [31] Multi-particle beam system according to any one of claims 22 to 30, which furthermore has a particle source for generating a charged particle beam, wherein the multi-particle beam system is configured to direct the charged particle beam as an illuminating particle beam onto the multi-aperture arrangement, the control system is set up to control the particle source, and wherein the particle source can be operated in a normal operating mode and in a flooding mode, wherein the particle source emits fewer charged particles and / or charged particles with lower energy in the flooding mode than in the normal operating mode. [32] Multi-particle beam system according to one of claims 22 to 31, which further comprises a UV source and / or an X-ray source for irradiating the multi-aperture arrangement. [33] Multi-particle beam system according to any one of claims 26 to 32, wherein the multi-particle beam system further features a beam stop that can be inserted into the particle-optical beam path in the lower area of ​​the multi-beam generator vacuum chamber, wherein the beam stop is configured to backscatter charged particles striking it, so that charged particles backscattered at the beam stop can irradiate the multi-aperture arrangement from the rear. [34] Multi-particle beam system according to any one of claims 22 to 33, wherein the multi-aperture arrangement is designed as a tongue, wherein a vibration generator is arranged on the multi-aperture arrangement, and wherein the control system is configured to control the vibration generator in the decontamination mode. [35] Multi-particle beam system according to the preceding claim, wherein the vibration generator provides mechanical vibrations or sound vibrations. [36] Multi-particle beam system according to any one of claims 22 to 35, wherein the multi-particle beam system further comprises a field generating means for generating an alternating electric field, which are arranged close to the surface of the multi-aperture arrangement, and which is configured to generate an alternating electric field in the decontamination mode, which is oriented parallel to the surface of the multi-aperture arrangement. [37] Multi-particle beam system according to any one of claims 26 to 36, which furthermore includes a pumping system with at least one vacuum pump, which is connected to the multi-jet generator vacuum chamber by means of a pumping line system, a particle trap is arranged within the pumping system to capture charged interfering particles. [38] Multi-particle beam system according to the preceding claim, wherein the particle trap is located directly in front of the entrance to the multi-beam generator vacuum chamber; or the particle trap is located directly after the outlet of a vacuum pump or source of interfering particles. [39] Multi-particle beam system according to any one of claims 37 to 38, wherein the particle trap comprises a capacitor and a flood gun for emitting charged particles, in particular electrons, wherein the condenser and the flood gun are arranged in such a way that they are successively penetrated by a gas stream when the multi-jet generator vacuum chamber is vented, wherein the flood gun is arranged in the pumping line system in the ventilation direction of a gas stream for ventilating the multi-jet generator upstream of the condenser, and the control system is set up to control and activate the capacitor for spreading an electric field and the flood gun for emitting charged particles during a ventilation process of the multi-beam generator vacuum chamber. [40] Multi-particle beam system according to the preceding claim, wherein the control is configured to limit a gas flow through the pump line system during a critical time interval of the venting process and / or de-venting process and to operate the particle trap during the critical time interval. [41] Multi-particle beam system according to any one of claims 37 to 38, wherein the particle trap comprises a first capacitor and a second capacitor, wherein the first condenser and the second condenser are arranged such that they are successively permeated by a gas stream when the multi-jet generator vacuum chamber is vented, wherein the first condenser in the pumping line system is arranged in the ventilation direction of a gas stream for ventilating the multi-jet generator upstream of the second condenser, and wherein the control is set up to drive the first capacitor to provide an alternating electric field and the second capacitor to provide a non-alternating electrostatic field. [42] Multi-particle beam system according to the preceding claim, wherein the control is configured to limit a gas flow through the pump line system during a critical time interval of the venting and / or de-venting process and to activate the particle trap during the critical time interval. [43] Multi-particle beam system according to claim 40 or 42, wherein the critical time interval corresponds to the time interval in which, during ventilation, the pressure in the pump line system is greater than or equal to 1 mbar. [44] Multi-particle beam system, in particular multi-beam particle microscope, comprising the following: a multi-beam generator with a multi-aperture arrangement, wherein the multi-aperture arrangement comprises a plurality of multi-aperture plates, wherein each of the multi-aperture plates has a multi-aperture area with a plurality of apertures and an exterior area around the multi-aperture area, wherein the plurality of apertures in a normal operating mode of the plurality-particle beam system is penetrated by a plurality of charged single-particle beams, wherein a first multi-aperture plate of the multi-aperture arrangement is provided, which is the first to be penetrated by the multitude of charged particles, and wherein the first multi-aperture plate has in its outer area a trapping trench system with at least one trapping trench for capturing charged perturbing particles. [45] Multi-particle beam system according to claim 44, wherein the first multi-aperture plate including the trap system has a metallic layer for stopping and absorbing charged particles striking it. [46] Multi-particle beam system according to one of claims 44 to 45, wherein the at least one trapping trench is formed circumferentially around the multi-aperture region. [47] Multi-particle beam system according to any one of claims 44 to 46, wherein the circumferential trap has one or more interruptions. [48] ​​Multi-particle beam system according to one of claims 44 to 47, wherein a trap trench is formed section by section linearly. [49] Multi-particle beam system according to one of claims 44 to 48, wherein the shape of a cross-section of a trap trench is rectangular, triangular or round-shell shaped and / or can be produced by etching technology. [50] Multi-particle beam system according to one of claims 44 to 49, wherein the trap system has a sequence of traps in the direction away from the multi-aperture region, with at least a first inner trap and a second trap arranged further outwards. [51] Multi-particle beam system according to claim 50, wherein the first trench has a first cross-section, and the second trench has a second cross-section, wherein the shape of the first cross-section and the second cross-section is identical, and where the dimensions of the first cross-section and the second cross-section are identical. [52] Multi-particle beam system according to claim 50, wherein the first trench has a first cross-section, and the second trench has a second cross-section, wherein the shape of the first cross-section and the second cross-section is identical, and where the dimensions of the first cross-section and the second cross-section are different. [53] Multi-particle beam system according to claim 50 or 52, wherein the entire multi-aperture area of ​​the first multi-aperture plate is arranged in a central trench, where the outer area of ​​the first multi-aperture plate is not located in the central trench, and the depth of each trench in the sequence of interceptor trenches arranged in the outer area increases from the inside out. [54] Multi-particle beam system according to any one of claims 44 to 53, wherein the entire multi-aperture area of ​​the first multi-aperture plate is arranged in a central trench, and where the following relation applies for a depth t of the central trench: 10µm ≤ t ≤ 200 µm. [55] Multi-particle beam system according to any one of claims 44 to 54, where the following relationship applies to a trench depth t of a trap trench: 10µm ≤ t ≤ 200µm, in particular 10µm ≤ t ≤ 20µm or 10µm ≤ t ≤ 18µm, and / or where the following relationship applies to a maximum trench width b of a trap trench: 8µm ≤ b ≤ 12µm, and / or where the following relation applies for a distance a between adjacent trenches: b / a ≥ 1.5, in particular b / a ≥ 2.

0. [56] Multi-particle beam system according to any one of claims 44 to 55, wherein the multiple particle beam system includes a particle source for generating a charged particle beam, and wherein the multi-particle beam system is configured to direct the charged particle beam as an illuminating particle beam onto the multi-aperture arrangement, and wherein the multi-particle beam system is configured to illuminate the multi-aperture area of ​​the first multi-aperture plate in a normal operating mode and to essentially not illuminate the exterior of the first multi-aperture plate. [57] A multi-particle beam system according to any one of claims 44 to 56, further comprising: a pre-aperture which, with respect to the particle-optical beam path, is arranged in front of the multi-aperture arrangement such that it can clip a widened particle beam before it strikes the multi-aperture arrangement, wherein the pre-aperture is designed in a graduated manner; and / or an exit aperture which is arranged according to the multi-aperture arrangement with respect to the particle-optical beam path, and which is designed in a stepped manner.

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