A multibeam particle microscope with a rapidly replaceable particle source, and a method for rapidly replacing the particle source of a multibeam particle microscope.

Abstract

A multibeam particle microscope with a rapidly replaceable particle source is disclosed. For this purpose, the multibeam particle microscope includes a specific double-sealing and tube separation module. This double-sealing and tube separation module allows for faster replacement of the interchangeable module with the particle source and, in some cases, protects the potentially sensitive particle optics components of the multibeam particle microscope from contamination.

Description

[Technical Field]

[0001] The present invention relates to a multibeam particle microscope that operates using a number of charged individual particle beams. More specifically, the present invention relates to a multibeam particle microscope that includes a rapidly replaceable particle source or cathode. [Background technology]

[0002] As the development of increasingly smaller and more complex microstructures, such as semiconductor components, progresses, there is a need to further develop and optimize planar manufacturing techniques and inspection systems for producing and inspecting these small-dimensional microstructures. For example, the development and production of semiconductor components requires monitoring the design of test wafers, and planar manufacturing techniques require process optimization for high-throughput and reliable production. More recently, there is a demand for the analysis of semiconductor wafers in reverse engineering and for customized, individual configurations of semiconductor components. Therefore, there is a need for inspection methods that can be used at high throughput to scrutinize microstructures on wafers with high precision.

[0003] Typical silicon wafers used in the production of semiconductor components have a maximum diameter of 300 mm. Each wafer has a maximum diameter of 800 mm. 2The semiconductor is subdivided into 30 to 60 repeating regions ("dies") of a certain size. The semiconductor device comprises multiple semiconductor structures that are layered on the wafer surface by planar integration techniques. The semiconductor wafer typically has a plane for the production process. The structural dimensions of the integrated semiconductor structures in this case range from a few micrometers to a few nanometers in critical dimensions (CD), and in the near future, structural dimensions will become even smaller, with structural dimensions or critical dimensions (CD) expected to correspond to 3 nm, 2 nm, or even smaller process nodes in the International Technology Roadmap for Semiconductors (ITRS). In the case of the aforementioned small structural dimensions, defects of critical dimension size must be rapidly identified over very wide areas. In some applications, the specification requirements for measurement accuracy achieved by inspection equipment are even higher, for example, twice or an order of magnitude higher. For example, the width of semiconductor features must be measured with an accuracy of less than 1 nm, e.g., 0.3 nm or less, and the relative position of semiconductor structures must be identified with an overlap accuracy of less than 1 nm, e.g., 0.3 nm or less.

[0004] The multi-beam scanning electron microscope (MSEM) is a relatively new development in the field of charged particle systems ("charged particle microscopes," CPM). Multi-beam scanning electron microscopes are disclosed, for example, in U.S. Patent No. 7,244,949 and U.S. Patent Application Publication No. 2019 / 0355544. In a multi-beam electron microscope, i.e., an MSEM, the sample is simultaneously irradiated with a number of individual electron beams arranged in a field or raster. For example, 4 to 10,000 individual electron beams can be supplied as primary radiation, with each individual electron beam separated from adjacent individual electron beams by a distance of 1 to 200 micrometers. An MSEM, for example, has about 100 distinct individual electron beams ("beamlets"), which are arranged, for example, in a hexagonal raster and separated by a distance of about 10 μm. Multiple charged individual particle beams (primary beams) are focused onto the sample surface being examined by a common objective lens. The sample may be, for example, a semiconductor wafer securely held in a wafer holder mounted on a movable stage. When the wafer surface is illuminated with a charged primary discrete particle beam, interaction products, such as secondary electrons or backscattered electrons, are emitted from the wafer surface. The starting points of the interaction products all coincide with such locations on the sample where a large number of primary discrete particle beams are focused. The amount and energy of the interaction products vary depending on the material composition and the surface shape of the wafer. The interaction products form multiple secondary discrete particle beams (secondary beams), which are collected by a common objective lens and incident on a detector placed on the detection surface by the projection imaging system of a multibeam inspection system. The detector comprises multiple detection regions, each with multiple detection pixels, and the detector acquires the respective intensity distributions of the secondary discrete particle beams. In this process, an image plane of, for example, 100 μm × 100 μm is obtained.

[0005] Conventional multibeam electron microscopes comprise a series of electrostatic and magnetic elements. At least some of the electrostatic and magnetic elements are configurable to match the focal position and astigmatism of a number of charged individual particle beams. Conventional charged particle multibeam systems further comprise at least one crossover plane of primary or secondary individual charged particle beams. Conventional systems further comprise a detection system for facilitating adjustment. Conventional multibeam particle microscopes comprise at least one beam deflector ("deflection scanner") that scans a region of the sample surface using a number of primary individual particle beams in a single motion to obtain an image plane of the sample surface.

[0006] As the demand for image quality increases, so do the demands on the multi-beam particle microscopes used for imaging. Stable operating parameters are crucial for high-quality recording. One of these operating parameters is the beam current intensity of the individual particle beams used to scan the sample surface.

[0007] For uniform beam current intensity in individual particle beams, the emission characteristics of the particle source, more precisely, the uniformity of emission characteristics across the entire emission angle used, is crucial. When using relatively large emission angles, the emission characteristics of the particle source, such as a thermal field emission (TFE) source, are no longer uniform across the entire beam. Consequently, the irradiance in the first multi-aperture plate of the corresponding particle beam system is also no longer uniform across the entire beam, and there is relatively large variation in the current density of the separate individual beams. However, in the case of multi-particle inspection systems, the system requirement is that the variation in current intensity between the various individual beams is small, typically less than a few percent, or even less than 1%, so that all individual image planes of the multi-image field are scanned by the same number of particles or electrons. This is a prerequisite, for example, for obtaining individual images with nearly identical brightness. The resolution of the individual images that can be obtained also depends on the individual beam current. There is an option to set the beam current individually for each individual particle beam. One option in this regard is disclosed in German Patent No. 102018007652, which is fully incorporated into this patent application by reference.

[0008] As the particle source or chip ages, further problems may arise with the particle source, such as a loss of brightness. Image brightness is also correlated with the brightness or lightness of the source. If the source loses brightness, this also applies to the image brightness. This can be compensated for, at least temporarily, by increasing the gain in the detection system, but this can lead to a deterioration of the signal-to-noise ratio (SNR) in the detector, resulting in a decrease in the contrast of the image that can be obtained. Another solution, at least temporary, is proposed in International Patent Application No. 2023 / 001402, the contents of which are fully incorporated by reference into this patent application, to change the voltage applied to the extractor electrode or to provide an additional electrostatic control lens between the extractor and the anode. Furthermore, it is proposed to estimate the remaining service life of the particle source or cathode chip and, optionally, to begin changing the particle source. Furthermore, International Patent Application No. 2023 / 001401 discloses a multi-beam particle microscope that enables high-precision beam current control. The disclosures in International Patent Application No. 2023 / 001401 are similarly incorporated in full by reference into this Patent Application.

[0009] However, particle sources or cathode tips will inevitably reach the end of their service life, and the particle source must be replaced. According to conventional technology, such replacement can take several hours or even several days, thus leading to downtime or shutdown of the multibeam particle microscope, which is inconvenient, especially when the multibeam particle microscope is integrated into a production line, as it results in relatively long and further system downtime.

[0010] To replace the particle source in a multibeam particle microscope, first, the area where the particle source or cathode tip is located must be made accessible. For example, the housing located in the upper area must be removed. The vacuum or high vacuum inside the multibeam particle microscope must be broken, and only then can a technician replace the particle source or cathode tip. After that, the multibeam particle microscope must be reassembled, then the area provided for vacuum evacuation must be suctioned out and baked out again. Finally, the multibeam particle microscope with the new or replaced particle source must be calibrated again. Particle source replacement usually takes about 30 hours, but it can sometimes take longer.

[0011] Replacing particle sources, in addition to being time-consuming, leads to further problems. Vacuum disruption can, in some cases, expose the particle optics used in multi-beam particle microscopes to contamination. The so-called micro-optics, a component of the multi-beam generator, is particularly susceptible to this. This contamination has a particularly significant impact on the beam quality of the individual particle beams produced and should be avoided whenever possible. [Overview of the Initiative]

[0012] Therefore, the object of this patent application is to provide a multi-beam particle microscope and related methods that allow for faster replacement of particle sources. In this case, the replacement of particle sources should be as simple as possible and at the most optimal timing possible.

[0013] Another objective is to avoid contamination of the multi-beam generator or micro-optical system as much as possible when replacing particle sources.

[0014] One or more objectives are achieved by the subject matter of the independent claims. Advantageous embodiments of the present invention are evident from the dependent claims.

[0015] This patent application claims priority to German Patent Application No. 102023107961.1, filed on 29 March 2023, the contents of which are incorporated in full by reference.

[0016] The central concept of this invention is to reduce the time spent on particle source replacement by significantly shortening the time required for vacuum evacuation of a multibeam particle microscope.

[0017] According to one aspect of the present invention, this is achieved by significantly reducing the volume that needs to be evacuated to replace the particle source, and the success in this regard is a result of the clever configuration of the double-sealed and barrel separation module. The interior of the double-sealed and barrel separation module is the only remaining volume that needs to be evacuated when it is replaced, compared to the entire system. In addition, by enabling module-based replacement of the particle source, it is possible to perform relative pre-screening and / or pre-adjustment of the source or its components relative to each other, thereby saving valuable time during the actual replacement of the particle source. Furthermore, in some modifications of the embodiments, the double-sealed and barrel separation module can provide protection against contamination to sensitive components of the multibeam particle microscope, such as the microoptics system.

[0018] According to a further aspect of the present invention, the time spent changing particle sources is minimized because the vacuum breaking, vacuum evacuation, and rebaking are completely unnecessary. Success in this regard is achieved, for example, by a solution with a storage facility equipped with multiple particle sources, or by changing particle sources in a complete vacuum, or by switching between multiple particle sources using electrostatic and / or magnetic deflection mechanisms. In these solution approaches, contamination can also be avoided.

[0019] Aspects of the present invention will be described in more detail below.

[0020] According to a first aspect of the present invention, the present invention relates to a multi-beam particle microscope comprising an exchangeable particle source, the multi-beam particle microscope comprising: a particle source configured to emit charged particles, a multi-beam generator configured to generate a first field of a plurality of charged first individual particle beams from the charged particles, a first particle optical unit comprising a first particle optical beam path and configured to image the generated first individual particle beams onto a sample surface of an object plane, whereby the first individual particle beams are incident on the sample surface at an incident location and form a second field, a detection system comprising a plurality of detection regions and forming a third field, a second particle optical unit comprising a second particle optical beam path and configured to image a second individual particle beam radiated from an incident location of the second field onto the third field of the detection regions of the detection system, a magnetic and / or electrostatic objective lens through which both the first individual particle beam and the second individual particle beam pass, a beam splitter disposed between the multi-beam generator and the objective lens in the first particle optical beam path and between the objective lens and the detection system in the second particle optical beam path, a sample stage for holding and / or positioning a sample during sample inspection, a controller configured to control the multi-beam particle microscope, a beam tube having at least two beam tube portions disposed between the particle source and the beam splitter, the beam tube being evacuated during operation of the multi-beam particle microscope and guiding charged particles or charged first individual particle beams therein during operation of the multi-beam particle microscope, and a double-sealing and lens barrel separation module disposed in a sealed state between two beam tube portions during operation of the multi-beam particle microscope, through which charged particles or the first individual particle beams pass and which is spatially separable into a first sub-module and a second sub-module when the multi-beam particle microscope is not operating, comprising. The first partial module includes a first sealing element configured to hermetically shield a beam tube portion adjacent to the particle source side when the first partial module and the second partial module are spatially separated. The second partial module includes a second sealing element configured to hermetically shield a beam tube portion adjacent to the beam splitter side when the first partial module and the second partial module are spatially separated. The double-sealing and lens barrel separation module includes a passage in an intermediate region between the first sealing element and the second sealing element, such that the intermediate region can be evacuated for operating the multi-beam particle microscope and the vacuum in the intermediate region can be broken to separate the first partial module and the second partial module.

[0021] At least one particle source is provided, but multiple particle sources are also possible. The charged particles may be, for example, electrons, positrons, muons, or ions, or other charged particles. Preferably, the charged particles are electrons produced using, for example, a thermal field emission source (TFE). However, other particle sources can also be used. The individual field regions (second fields) of the object assigned to each first individual particle beam are raster-scanned, for example, row by row or column by column. In this case, it is preferable that the individual field regions are adjacent to each other or cover the object or a part of the object in a mosaic-like manner. The individual field regions may be substantially separated from each other but overlap each other in their peripheral regions. In this way, it is possible to obtain an image of the object that is as complete and continuous as possible. The individual field regions preferably have a rectangular or square shape, as this is the easiest way to implement the scanning process using particle radiation. The individual field regions are preferably arranged as rectangles overlapping vertically across different rows, such that the overall result is a hexagonal structure. In the case of a hexagon, it is advantageous to have 3n(n-1)+1 particle beams, where n is any natural number. Other arrangements of individual field regions, such as square or rectangular rasters, are similarly possible. The second individual particle beam may be backscattered electrons or secondary electrons. In this case, it is preferable that low-energy secondary electrons are used to generate the image for analysis. However, it is also possible to use mirror ions / mirror electrons as the second individual particle beam, i.e., as the first individual particle beam that is inverted immediately upstream of or at the object.

[0022] The beam tube represents the region of the multibeam particle microscope that is evacuated when the multibeam particle microscope is in operation. In this context, the beam tube itself can have a single-part or multi-part design. The beam tube may comprise a tubular portion and / or a chamber-like portion. Charged particles or a beam of charged individual particles are guided into the beam tube during the operation of the multibeam particle microscope. The beam tube itself may be made of, for example, steel or stainless steel, or at least partially titanium. The two beam tube portions explicitly mentioned in claim 1 are spaced apart from each other and substantially separated from each other by a double seal and tube separation module. In this case, the double seal and tube separation module is sealed and positioned between the two beam tube portions during the operation of the multibeam particle microscope. As a result, the double seal and tube separation module is designed to maintain within it the vacuum present in the beam tube or throughout the two beam tube portions during the operation of the multibeam particle microscope. The double seal and tube separation module is spatially separable into a first submodule and a second submodule when the multibeam particle microscope is not in operation. This separability is expressed in words using the term "lens tube separation module." Again, each of the first and second submodules can have a single-part or multi-part design. An intermediate piece, such as an adapter, can be placed between the first and second submodules.

[0023] The term "double-sealed module" already indicates that the double-sealed and tube-separated module is provided with at least two sealing elements. In this configuration, the first submodule comprises a first sealing element, and the second submodule comprises a second sealing element. The first sealing element is configured to seal the adjacent beam tube portion on the particle source side when the first and second submodules of the double-sealed and tube-separated module are spatially separated. In this configuration, the closure itself may be direct or indirect. The sealing element may have dimensions that match the diameter of the adjacent beam tube portion, but it does not need to reach the entire width of the first submodule. The second sealing element is similarly configured to seal the adjacent beam tube portion on the beam splitter side when the first and second submodules of the double-sealed and tube-separated module are spatially separated. Therefore, by manipulating the first and second sealing elements before disassembling or separating the double seal and tube separation module into the first and second submodules, both can be sealed in a vacuum-sealed manner. This sealing is for elements or regions of the beam tube located above and below the double seal and tube separation module. As a result, the vacuum in these regions is broken, eliminating the need to re-evacuate them in a later stage following particle source replacement.

[0024] Instead, the vacuum is simply broken within the double-seal and tube separation module, or recreated in a later stage. For this purpose, the double-seal and tube separation module includes a passage in an intermediate region between the first and second sealing elements, so that the intermediate region can be evacuated to operate the multi-beam particle microscope and the vacuum within the intermediate region can be broken to separate the first and second modules. This passage may be a single-part or multi-part passage. In a simple exemplary embodiment, the passage is, for example, a drilled hole into which a conduit is connected in a vacuum-sealed manner, and the conduit is further connected to or can be connected to a vacuum pump.

[0025] According to a preferred embodiment of the present invention, a multibeam particle microscope is A replacement module comprising a first partial module of the double sealing and barrel separation module, and also a multibeam particle microscope component including a particle source, positioned above the double sealing and barrel separation module with respect to the particle light beam path. The replacement module further comprises the following: In this case, the replacement module is configured to be replaced as a whole within the multibeam particle microscope. The replacement module can therefore comprise not only the particle source itself, but also other elements of the multibeam particle microscope as substantial components. This depends in principle on the position of the double-sealing and tube separation module in the illumination tube or particle light beam path of the multibeam particle microscope. In this case, the particle source to be replaced may further comprise one or more parts. The particle source may comprise, for example, a cathode, a drawer electrode, and an anode. The particle source may further comprise a suppressor electrode. The arrangement of these elements within the particle source may be pre-examined and / or pre-adjusted in advance within the (new) replacement module. This facilitates the overall adjustment of the (new) replacement module to the rest of the illumination tube of the multibeam particle microscope. The replacement module comprises all the components of the multibeam particle microscope, which are, as preferred, positioned above the double-sealing and tube separation module with respect to the particle light beam path. In other words, the replacement module in this case comprises the entire "head" of the illumination tube.

[0026] According to a preferred embodiment of the present invention, a multibeam particle microscope is A focusing lens system located downstream of the particle source and upstream of the multibeam generator in the particle light beam path, through which charged particles pass. The double-sealing and tube separation module is further positioned between the focusing lens system and the multibeam generator. In this case, the focusing lens system may comprise one or more focusing lenses. When the double-sealing and tube separation module is positioned between the focusing lens system and the multibeam generator, in a variation of this embodiment, the double-sealing and tube separation module is positioned so that charged particles first pass through all the focusing lenses of the focusing lens system before reaching the multibeam generator. Thus, in this embodiment of the present invention, it is a fact that the focusing lens system is a component of the replacement module. In this embodiment, it is also a fact that the double-sealing and tube separation module is positioned above the multibeam generator. Thus, in this process, the multibeam generator is not replaced. Instead, when replacing the replacement module containing the particle source, in a variation of this embodiment, the beam tube portion adjacent to the beam splitter side, which is still upstream of the multibeam generator in the direction of the particle light beam path, is shielded in a sealed state. As a result of this shielding, when the particle source is replaced, the multibeam generator, specifically the micro-optical system located within the multibeam generator, is protected from contamination.

[0027] According to a more preferred embodiment of the present invention, a multibeam particle microscope is A focusing lens system located downstream of the particle source and upstream of the multibeam generator in the particle light beam path, through which charged particles pass. The focusing lens system comprises a first, specifically magnetic focusing lens, and a second, specifically magnetic focusing lens, and the double sealing and barrel separation module is positioned between the first and second focusing lenses. The double sealing and barrel separation module can be positioned, for example, within the drift path of the focusing lens system. This saves mounting space or barrel height overall. In this embodiment of the present invention, the replacement module comprises only a part of the focusing lens system, in particular at least one, specifically magnetic focusing lens. Therefore, the replacement module is smaller or comprises fewer components, which requires fewer resources. Nevertheless, the double sealing and barrel separation module is located above the multibeam generator in the particle light beam path, and as a result, the multibeam generator can be protected by sealing the second sealing element of the second sub-module of the double sealing and barrel separation module when the particle source is replaced.

[0028] Theoretically, a double sealing and barrel separation module could be placed between the particle source and the focusing lens system. However, in practice, this is likely to be avoided because the particle source and focusing lens system are positioned very close to each other, and there is usually not enough space left for the arrangement of the double sealing and barrel separation modules.

[0029] According to a more preferred embodiment of the present invention, a multibeam particle microscope is A field lens system located downstream of the multi-beam generator and upstream of the beam splitter in the particle light beam path, through which the charged first individual particle beam passes. The field lens system further comprises a first, specifically magnetic field lens, and a second, specifically magnetic field lens, with the double sealing and tube separation module positioned between the first and second field lenses. However, the field lens system may, of course, comprise three or more field lenses. In this case, the first field lens is considered the field lens closest to the multibeam generator. Thus, in this embodiment of the present invention, the illumination tube is separated directly below the multibeam generator or immediately after the first field lens. As a result, the replacement module itself is relatively large or complex. However, this offers the advantage that the entire relatively large replacement module, comprising the particle source and multibeam generator, and optionally a focusing lens system located between the particle source and the multibeam generator, can be pre-examined and / or pre-adjusted before the necessary replacement of the particle source. As a result, the replacement of the particle source can be performed more quickly within the scope of the replacement module. Furthermore, contamination or uncleaning of the entire multibeam generator does not occur.

[0030] According to a preferred embodiment of the present invention, the double-sealed and isolated module is 10 -10 The module is configured to achieve mbar or better ultra-high vacuum, and / or double-sealed and separated, 10 -9 It is configured to achieve a leakage rate of less than mbar / l / second. As a result, when separating the first and second sub-modules, it is possible to maintain the high vacuum in the (old or new) replacement module and the remaining illumination tube. Furthermore, this allows for the use of the double-sealed and separated modules without problems during the operation of the multi-beam particle microscope, without degradation of the ultra-high vacuum required for the multi-beam particle microscope or excessively high leakage rates.

[0031] According to a preferred embodiment of the present invention, the double seal and lens barrel separation module are conductive and have a relative permeability μ r μ rThe material contains or is composed of a material satisfying ≤1.005. This relative permeability is achieved by several types of stainless steel alloys and several types of titanium-based materials. Detailed information regarding the relative permeability of the material used to manufacture the beam tube portion can also be found in German patent application No. 102022124933.6, the disclosure of which is fully incorporated into this patent application by reference. The material specified in said patent application can also be used as material for double sealing and tube separation modules.

[0032] According to a preferred embodiment of the present invention, the first and / or second sealing elements of the double sealing and barrel separation module comprise one element from the list of ultra-high vacuum sliders, flap valves, and pendulum valves. However, the first and / or second sealing elements may be designed in any other way.

[0033] According to a preferred embodiment of the present invention, the first sealing element and / or the second sealing element are configured to operate manually, pneumatically, or electrically. In this configuration, if not manually operated, the first and / or second sealing elements can be controlled, specifically, using signals from a multibeam particle microscope controller. However, non-manual control can also be performed independently of the multibeam particle microscope controller.

[0034] According to a preferred embodiment of the present invention, the overall height h of the double seal and tube separation module, measured along the optical axis of the multibeam particle microscope when installed, satisfies the following relationship: h ≤ 8.0 cm, preferably h ≤ 7.0 cm, and most preferably h ≤ 6.0 cm. In this case, the double seal and separation module has, by design, a minimum height h of, for example, about 5.0 cm, in order to ensure the necessary stability and airtightness of the double seal and tube separation module. However, at the same time, this height h must be kept as low as possible so as not to unnecessarily increase the overall height of the illumination tube, which is important in any case. In this situation, the ceiling height of the examination room is often a limiting factor. Furthermore, the specified overall height h of the double seal and tube separation module is low enough to accommodate the double seal and tube separation module, for example, within a drift path of the illumination tube. Such a drift path may be provided, for example, within a focusing lens system.

[0035] According to a more preferred embodiment of the present invention, the double-sealed and separated module further comprises a heating element disposed within the double-sealed and tube-separated module. This heating element may accelerate, or even simply enable, the creation of a high vacuum within the double-sealed and tube-separated module. Localized heating may increase the desorption rate of the chamber walls, thereby enabling the achievement of an ultra-high vacuum more quickly. The heating element can be controlled using the multibeam particle microscope controller, either while installed or during operation of the multibeam particle microscope. In this context, the heating element itself can be designed in various ways. The heating element may be designed, for example, as a flat heating plate or flat mat, in which case it can be inserted flat in the intermediate space between, for example, a first sub-module and a second sub-module. However, the heating element may also be substantially cylindrical and / or wrapped around or suspended from one or both sub-modules. The heating element is made up of multiple parts and / or multiple heating elements can be provided, for example, a first heating element is located in a first sub-module of the double sealing and barrel separation module, and a second heating element is located in a second sub-module of the double sealing and barrel separation module.

[0036] According to a more preferred embodiment of the present invention, the double-sealed and barrel separation module further comprises an adjustment member for adjusting a replacement module, the adjustment member being located adjacent to or incorporated into the first sub-module on the particle source side. The adjustment member facilitates extremely precise adjustment of the (new) replacement module on the remaining illumination barrel of the multibeam particle microscope. The adjustment member may include, for example, a bellows that allows for lateral, axial, and / or tilting movement when fine-tuning the replacement module on the remaining illumination barrel. In this case, the adjustment member may be flange-mounted on the first sub-module, for example. However, it is also conceivable that the adjustment member and bellows be designed integrally with the first sub-module.

[0037] According to a more preferred embodiment of the present invention, the particle source of a multibeam particle microscope comprises a cathode tip, an extractor aperture (stop), and an anode aperture, which are either flush or otherwise arranged on the same plane. The particle source may further include a suppressor electrode that surrounds the cathode tip, for example, as the side of a cylinder, and serves to suppress the lateral emergence of electrons from the cathode tip. The cathode tip may be, for example, a thermal field emitter, but other configurations are possible in principle. With respect to the aforementioned coplanar arrangement of the cathode tip, extractor aperture, and anode aperture, the centers of the cathode tip, the extractor aperture, and the anode aperture are precisely aligned, i.e., on the optical axis. This correct positioning is particularly important for high-precision recording using a multibeam particle microscope, and it ensures optimal use of the particle source or the particles supplied from the particle source. Spatially speaking, the cathode tip emits a particle cone, and the beam current in the cross-section of the cone has a roughly plateau-shaped change over a wide range, then changes toward the edge of the cone, typically increasing toward the edge (forming "teeth"), and then rapidly decreasing just outside. Here, the region outside the particle cone beam can be blocked by the extractor aperture and / or anode aperture. In other words, charged particles typically occur on at least a portion of the extractor aperture and / or anode aperture. This fact can be used for monitoring the cathode tip and / or adjusting the components of the particle source. Thus, in this embodiment of the invention, the extractor aperture comprises an extractor current meter configured to record a current pattern having spatial resolution around the extractor aperture, and / or the anode aperture comprises an anode current meter configured to record a current pattern having spatial resolution around the anode aperture. In this context, it should be understood that spatial resolution does not mean only the overall current that is determined. Instead, the position dependence of the beam current can also be reproduced in the current pattern. In this case, the position dependence of the beam current is related to at least two locations, preferably two or more locations or sectors.The drawer current meter and / or anode current meter may comprise, for example, mutually insulated sensor plates, which are grounded current measuring probes positioned around each aperture, with the current measuring device connected between the plates and ground. Alternatively, a scintillator on the aperture can be used as a current meter, and the brightness distribution on the scintillator plate can be determined. Thus, the beam current is determined indirectly in this case. In principle, other embodiments are also possible.

[0038] According to a more preferred embodiment of the present invention, a cathode positioning means is provided to set the position of the cathode relative to the drawer throttling and / or anode throttling based on a recorded current pattern. For example, the cathode tip can be displaced, rotated, and / or tilted in all three spatial directions. For this purpose, for example, the cathode tip can be mounted using a hexapod. However, other fine-tuning means or mounting bases are also possible.

[0039] According to a more preferred embodiment of the present invention, a multibeam particle microscope is conductive coating element The covering element is further positioned above the multibeam generator with respect to the particle beam path and is insertable into the particle beam path such that, when inserted, the multibeam generator is covered by the covering element. The conductive covering element can be designed, for example, as a metal slider or metal cantilever, or as a movable disk. This covering further protects the multibeam generator during particle source exchange. During particle source exchange, the conductive covering element not only protects from contamination but also protects the electronic components mounted on the multibeam generator from scattered electrons and / or high-energy light radiation. Furthermore, it is possible to provide a multibeam particle microscope that has the conductive covering element described but does not have the double sealing and tube separation module according to the present invention.

[0040] According to a more preferred embodiment of the present invention, the covering element is designed as a metal cantilever that is displaceable in a direction perpendicular to the particle light beam path between a first fastening position and a second fastening position. The metal cantilever has through holes, the diameter of which matches the diameter of the beam tube adjacent to the through hole, and in the first fastening position, charged particles can pass through the through holes and through the covering element without obstruction. The metal cantilever specifically has a circular recess, the diameter of which matches the diameter of the adjacent beam tube, and in the second stopper position, charged particles are incident on the recess. Thus, the metal cantilever is, for example, a slider that can move back and forth between two stopper positions, in one case introducing a through hole into the particle light beam path, and in the other case introducing a circular recess. This modification has the further advantage that, in addition to its protective function, it can be used for the purpose of beam current measurement, and therefore for monitoring and / or adjustment purposes. This is because, according to a more preferred embodiment of the present invention, a beam current meter is specifically located in the circular recess and / or the circular recess is connected to a beam current meter. This makes it possible, for example, to measure scattered electrons. Alternatively, or in addition, the beam current can also be measured directly.

[0041] In a modified embodiment, the metal cantilever has a specific thickness and extends laterally across the entire beam tube or through the beam tube. This, in principle, enables the extension of the beam tube and allows for better protection of the multibeam generator, including electronic equipment and / or circuits located on the multibeam generator, from, for example, the generated X-ray radiation. The beam current meter can also directly or indirectly confirm the beam current in this modified embodiment. In this modified embodiment as well, in principle, it is possible to record or monitor the beam current with spatial resolution.

[0042] Modifications of the embodiments described above according to a first aspect of the present invention can be combined with one another, in whole or in part, as long as no technical inconsistencies result.

[0043] According to a second aspect of the present invention, the present invention is A multibeam particle microscope with interchangeable modules, as described in the various modifications of the above embodiments, At least one other interchangeable module for the multibeam particle microscope, A storage cabinet with at least one vacuum-sealed connector for at least one other replacement module In a system comprising the above, the storage chamber is configured to store the interior of another replacement module within the storage chamber in a high vacuum, specifically an ultra-high vacuum, when the first sealing element of the other replacement module is open. In this case, it is preferable that the replacement module and the other replacement module are structurally identical. The replacement module can be pre-examined and / or pre-adjusted before bringing at least one other replacement module into the storage chamber. This significantly saves time when changing particle sources in a multibeam particle microscope. Furthermore, in the case of the storage chamber, it is possible to pre-evacuate and / or bake at least one other replacement module, thereby reducing the critical evacuation and baking time when changing particle sources, or to perform evacuation and baking before actually changing the particle source. At least one vacuum-sealed connector of the storage chamber is sized so that a replacement module or a first sub-module of a double-sealed and tube-separated module can be vacuum-sealed to the connector. The connector on the storage side preferably has the same dimensions and airtightness as the second partial module of the double seal and tube separation module that remains on the rest of the irradiating tube when the particle source is replaced. However, the connector may also have other embodiments, as long as there are corresponding connection options and the required sealing characteristics.

[0044] According to a third aspect of the present invention, the present invention relates to a method for replacing the particle source of a multibeam particle microscope as described in the various embodiments described above. In this case, the multibeam particle microscope comprises the replacement module described above, and the method is as follows: Steps to close the first sealing element and the second sealing element of the double sealing and barrel separation module, Steps to break the vacuum in the region between the first sealing element and the second sealing element of the double sealing and barrel separation module, The steps include spatially separating the double-sealed and tube separation module into a first sub-module and a second sub-module, thereby separating the first replacement module, which includes the first particle source, from the rest of the multibeam particle microscope or from the remaining illumination tube of the multibeam particle microscope, The step of assembling a second double-seal and tube separation module, wherein the second replacement module, which includes a second particle source, is placed on the remainder of the multibeam particle microscope or on the remainder of the illumination tube, and the second replacement module is pre-vacuumed and the first sealing element of the second replacement module is closed. Steps include: evacuating the area between the first sealing element and the second sealing element of the second double sealing and barrel separation module; After vacuum evacuation is performed, the first sealing element of the second double seal and barrel separation module and the second sealing element of the second double seal and barrel separation module are opened. Includes.

[0045] The terms used herein in relation to the method according to the present invention are the same terms already used and defined above in relation to multibeam particle microscopes or systems. The method described describes in detail the replacement of a first replacement module with a first particle source for a second replacement module with a second particle source, using a double-sealed and barrel separation module. The double-sealed and barrel separation module is spatially separable into a first submodule and a second submodule. Within the scope of this method, as described above, the double-sealed and barrel separation module is, so to speak, reassembled. The second submodule is retained in the same state, but the first submodule is replaced as it is considered part of the replacement module. Thus, the first double-sealed and barrel separation module is the original double-sealed and barrel separation module, and the second double-sealed and barrel separation module is the newly assembled double-sealed and barrel separation module. Similar descriptions apply to a third replacement module, possibly equipped with a third particle source, and a third double-sealed and tube-separated module, which may or may not be assembled in this manner.

[0046] According to a modified version of a preferred embodiment of this method, this method is Steps to heat the first double seal and barrel separation module and / or the second double seal and barrel separation module. This further includes the following: This heating can be performed when the double-seal and tube separation module is installed in the multibeam particle microscope, and the heating may be maintained even during the normal operation of the multibeam particle microscope. In addition, or alternatively, it is also possible to heat a portion of the double-seal and tube separation module located in the storage chamber so that the entire replacement module in the storage chamber can be evacuated more quickly and / or more sustainably. For this purpose, the first sealing element is opened in the storage chamber.

[0047] According to a further preferred embodiment of this method, the method further includes the step of pre-adjusting and / or technically pre-examining the second replacement module before it is placed on the rest of the multibeam particle microscope. This is one of the main advantages of the method according to the present invention, or of the multibeam particle microscope according to the present invention. Pre-adjustment and / or technical pre-examination can save valuable time when exchanging particle sources. Technical pre-examination and / or pre-adjustment may include establishing an ultra-high vacuum (evacuation with baking), breaking in the tip cathode (adjustment with high voltage), evaluating the emission characteristics of the tip cathode, and making adjustments to guide the electron beam to align with the optical axis.

[0048] According to a more preferred embodiment of the present invention, the method further includes the step of storing the second replacement module in a storage chamber under evacuated vacuum. As a result, the second replacement module can be used or replaced with the first replacement module very quickly. The storage chamber itself can be located, for example, in the same room as the multibeam particle microscope, but may be in an adjacent room or at least in the same building. The shorter the path between the storage chamber and the multibeam particle microscope, the faster the overall particle source replacement process proceeds. Furthermore, the possibility of disrupting adjustments when transporting the second replacement module to the multibeam particle microscope is avoided. However, it is also possible that the storage chamber is located in a remote location relative to the multibeam particle microscope. In this case, the storage itself may be carried out over a relatively long period, for example, several months or several years. Throughout this process, it is preferable that the vacuum in the stored replacement module is maintained, and that the first sealing element is kept open at all times.

[0049] According to a more preferred embodiment of the present invention, this method is The steps include: positioning the second replacement module isotropically on the rest of the multibeam particle microscope or illumination tube; A step of adjusting the second replacement module using an adjustment member, and / or Step 1: Adjust the second replacement module using an electric and / or magnetic deflection field that deflects the charged particle and / or the first charged individual particle beam. This further includes the following. In this situation, it is ideal to position the second replacement module isotropically relative to or on the rest of the multibeam particle microscope without the need to perform any further adjustment processes.

[0050] The adjustment of the second interchangeable module using adjustment components essentially represents a mechanical adjustment, i.e., adjustment by mechanical means, where the second interchangeable module can be displaced, rotated, and / or tilted relative to, for example, the rest of the multibeam particle microscope. When the second interchangeable module is adjusted using electrical and / or magnetic deflection fields, it is possible to eliminate the need for additional mechanical adjustments. However, additional mechanical adjustments may still be required. An example of adjusting the second interchangeable module using electrical and magnetic deflection fields is, for example, modifying the control of one or more focusing lenses and / or electrical and / or magnetic deflectors or dual deflectors provided in the focusing lens system. It is also possible to provide one or more additional electrical and / or magnetic deflectors specifically for adjustment purposes.

[0051] According to a more preferred embodiment of the present invention, this method is A step of monitoring the current pattern in the region of the particle source, The steps include adjusting the components of the particle source relative to each other based on the current pattern, and It also includes. The components of a particle source may include, for example, a cathode tip, a lead-out aperture, and an anode aperture, which should be aligned on the same plane. In this scenario, monitoring the current pattern in the region of the particle source can be performed on the lead-out aperture and / or anode aperture, and, for example, specifically, a current pattern with spatial resolution can be recorded. In this case, the current pattern can be effectively used, in particular, for tuning purposes.

[0052] According to a more preferred embodiment of the present invention, this method is A step of monitoring the current pattern in the region of the particle source, In both cases, the remaining service life of the particle source is predicted based on the current pattern, and specifically, the step of initiating the replacement of the particle source is... This further includes the following. In principle, it is known that the emission characteristics of a particle source change as the particle source's service life progresses, and how the emission characteristics typically change. Therefore, by monitoring the current pattern during the operation of a multibeam particle microscope, changes in the particle source can be observed. This makes it possible to predict the remaining service life of the particle source and, specifically, to initiate a timely replacement of the particle source.

[0053] Alternatively, or in addition, the remaining service life of a particle source can be derived from other current measurements. For example, an indicator in this regard can be derived from a measurement of the beam current on the first multi-aperture plate of a multi-beam generator. Further information in this regard can be found in International Patent Application No. 2023 / 001402, which has already been cited at the beginning, and its disclosure is fully incorporated into this patent application by reference.

[0054] According to a more preferred embodiment of the present invention, the method is carried out in whole or in part multiple times, specifically, by placing a third replacement module with a third particle source and / or another replacement module with another particle source on the rest of the multibeam particle microscope or on the remaining illumination tube. This method can be carried out, for example, until all replacement modules stored in the storage chamber are actually mounted on the multibeam particle microscope. Furthermore, it is naturally possible to fill the storage chamber with another replacement module in the meantime, and therefore, in principle, to carry out the method according to the present invention for any desired period of time.

[0055] According to a fourth aspect of the present invention, the present invention relates to a multibeam particle microscope equipped with an interchangeable particle source, wherein the multibeam particle microscope is A first vacuum region comprising a first particle source positioned in an operational location and configured to emit charged particles, A multibeam generator configured to generate a first field of a large number of charged individual particles from charged particles, A first particle optical unit is provided with a first particle light beam path and configured to image the generated first individual particle beam onto the sample surface of the object surface, thereby causing the first individual particle beam to enter the sample surface at the point of incidence and form a second field. A detection system equipped with multiple detection areas, forming a third field. A second particle optical unit comprising a second particle light beam path, configured to image a second individual particle beam emitted from the incident site of the second field onto a third field in the detection region of the detection system, A magnetic and / or electrostatic objective lens through which both the first individual particle beam and the second individual particle beam pass, A beam splitter is positioned between the multibeam generator and the objective lens of the first particle light beam path, and between the objective lens and the detection system of the second particle light beam path. A sample stage for holding and / or positioning a sample during sample inspection. A controller configured to control a multibeam particle microscope. A second vacuum region comprising a storage unit having at least one second particle source having the same structure as the first particle source as a replacement particle source, and A transfer mechanism for vacuum-transferring a second particle source from a storage unit in a second vacuum region to an operational position within the first vacuum region. It is equipped with.

[0056] In this context, “operable position” should be understood to mean the position in which the particle source is located within the multibeam particle microscope during the operation of the multibeam particle microscope. In this embodiment of the present invention, the operable position is not merely a storage position for storing the particle source. The operable position is therefore different from the storage position in this embodiment of the present invention. In contrast, one or more such storage positions are found within the storage unit.

[0057] According to this embodiment of the present invention, the working particle source, i.e., the particle source in operation or currently provided for operation, is located within a vacuum region. Therefore, the operational location is located within a vacuum region, particularly within a first vacuum region. Similarly, a storage unit, which includes at least a second particle source as a replacement particle source, is also located within a vacuum region, particularly within a second vacuum region. Therefore, the storage location is located within a vacuum region. In this situation, the first and second vacuum regions can be formed as two separate vacuum chambers. The two vacuum chambers can be separated from each other, for example, by a gate. However, the first and second vacuum regions can also be located within the same vacuum chamber, i.e., without a gate in between. The second vacuum region can also be composed of multiple vacuum chambers. The effect is the same. In a variation of this embodiment of the present invention, the replacement of the particle source can be carried out in a complete vacuum. Therefore, it is possible to avoid potentially required vacuum evacuation of the vacuum chamber and necessary baking of the vacuum chamber. Therefore, the particle source can be replaced much more quickly.

[0058] In this embodiment of the present invention, a transport mechanism is configured for vacuum transporting a second particle source from a storage unit in a second vacuum area to an operational position in a first vacuum area. In this configuration, it is also possible, optionally, for the transport mechanism to be further configured to vacuum transport the first particle source from an operational position in the first vacuum area to a storage unit in the second vacuum area. Thus, it is possible not only to transport a replacement particle source to an operational position in a complete vacuum, but also to remove the old particle source from the operational position. In this configuration, the transport mechanism itself can have a single-part or multi-part design. For example, one transport rod or multiple transport rods can be used for transport under vacuum conditions. The operation of the transport rods can be performed, for example, manually or automatically by a suitable motor and / or sensor system. The transport mechanism may further include mechanical positioning means such as guides, positioning pins, screws, or fasteners.

[0059] The particle source itself may comprise a unit made up of multiple components, such as a cathode tip, a drawer throttling, and an anode throttling. The particle source may also include a suppressor electrode. However, the particle source may consist only of a cathode tip. In this embodiment according to the fourth aspect of the present invention, the replacement particle source unit is preferably smaller than the replacement module according to the first aspect of the present invention. This is because, since the replacement particle source is already in a vacuum, there is no need to simultaneously replace the housing parts that house the particle source and maintain the vacuum around it. Furthermore, within the scope of the modifications of this embodiment, it is important to keep the storage space for the replacement particle sources as small as possible so that as many replacement particle sources as possible can be accommodated in the storage unit. Nevertheless, the modifications of this embodiment are preferably of a pre-configured replacement unit comprising multiple components, such as a cathode tip, a drawer throttling, and an anode throttling, and optionally a suppressor electrode, because in that case, these components of the replacement particle source can be pre-configured before actually replacing the particle source in a vacuum. In other words, the storage unit will only contain replacement particle sources that have been pre-screened and / or pre-calibrated for future use. This makes it easier to correctly position and adjust the replacement particle sources to an operational position after replacement, resulting in time savings.

[0060] According to a preferred embodiment of the present invention, the storage unit has a plurality of storage positions or storage spaces arranged according to a physically linear topology for replacement particle sources. For example, in a variation of this embodiment, a storage bus system that is displaceable, for example, in the Z direction, on a stage, can be used as the storage unit. A transport rod may be used to move the storage bus system. In any case, in a variation of this embodiment, the replacement particle sources can be transported to their initial positions using linear movement by an appropriate transport mechanism for subsequent transport from a second vacuum region to a first vacuum region.

[0061] According to an alternative embodiment of the present invention, the storage unit has a plurality of storage positions or storage spaces for replacement particle sources, arranged according to a physically star-shaped topology. Thus, in a modification of this embodiment, the storage positions are, for example, arranged in a ring, and the replacement particle sources can then be transported to the center of the ring for transport to an operational position. In other words, the operational position of each working particle source is located midway between the storage positions, at the center of the storage unit. Since each replacement particle source is transported to the “center” of the topology, a star-shaped topology is again referred to in this situation, and a ring-shaped topology is not, for example. In a modification of this embodiment, the transport mechanism itself may comprise, for example, a plurality of transport rods, preferably corresponding to the number of storage positions. In other words, each transport rod is used for transport from a storage position to an operational position. In a modification of this embodiment, the operational positions themselves are accessible from various directions.

[0062] According to an alternative embodiment of the present invention, the storage unit has a plurality of storage positions or storage spaces for replacement particle sources, arranged according to a physically ring-shaped topology. In this embodiment, for replacement of the particle source, the replacement particle source is moved along the ring. The operable positions in this case are located on this ring. This topology may be realized, for example, using a turret mechanism, such as a rotating stage in a high vacuum housing the replacement particle source.

[0063] According to a more preferred embodiment of the present invention, a multibeam particle microscope is At an operational position, each unit is electrically in contact with an operating particle source, An adjustment unit precisely positions each operating particle source within its operational range. The following are further provided. The contact unit may have a single-part or multi-part design. The electrical contact may have one or more contact points. For example, a separate contact point can be provided for each electrode of the particle source. For example, the contact unit can be movable to an operable position using, for example, a unidirectionally displaceable stage. For example, in this way, a connector with multiple electrical contacts can be realized, and thus a replacement particle source can be connected. Electrical contact can, in principle, be established in a vacuum using connectors, clamps, and / or sliding contacts.

[0064] The adjustment unit for precise positioning of the particle sources, each operating at a movable position, can again, in this case, have a single-part or multi-part design. The adjustment unit can be implemented in various ways, for example, by a 3-D stage and / or by a piezoelectric element. Other embodiments are also possible.

[0065] According to a preferred embodiment of the present invention, each replacement particle source comprises a tip cathode, an extractor electrode, and an anode that are pre-adjusted relative to each other and / or technically pre-tested. As a result, in a variation of this embodiment, relative fine-tuning between the components of the replacement particle source can be largely or completely eliminated, which saves time.

[0066] According to a fifth aspect of the present invention, the present invention relates to a multibeam particle microscope equipped with an interchangeable particle source, wherein the multibeam particle microscope is Multiple identically constructed particle sources, fixedly positioned in space and configured to emit charged particles, A switching means configured to switch between multiple particle sources, so that at any given time, exactly one of the particle sources becomes the active particle source emitting charged particles. Electrical and / or magnetic deflection means configured to deflect charged particles emitted from each operating particle source onto the optical axis of a multibeam particle microscope, A multibeam generator configured to generate a first field of numerous charged first individual particle beams from charged particles from a particle source, A first particle optical unit is provided with a first particle light beam path and configured to image the generated first individual particle beam onto the sample surface of the object surface, thereby causing the first individual particle beam to enter the sample surface at the point of incidence and form a second field. A detection system equipped with multiple detection areas, forming a third field. A second particle optical unit comprising a second particle light beam path, configured to image a second individual particle beam emitted from the incident site of the second field onto a third field in the detection region of the detection system, A magnetic and / or electrostatic objective lens through which both the first individual particle beam and the second individual particle beam pass, A beam splitter is positioned between the multibeam generator and the objective lens of the first particle light beam path, and between the objective lens and the detection system of the second particle light beam path. A sample stage for holding and / or positioning a sample during sample inspection. A controller configured to control the particle source, switching means, and deflection means. It is equipped with the following features. The controller can, of course, also control the multi-beam particle microscope as a whole. In this situation, as mentioned above, the controller itself can have a single-part or multi-part design.

[0067] In this embodiment of the present invention, a transport mechanism for transporting particle sources is not required. Instead, the working particle source and the replacement particle source are pre-fixed and positioned in a space (under vacuum) within the multibeam particle microscope. Thus, in this modification of the embodiment, there is switching between particle sources rather than mechanical transport. Therefore, this modification of the embodiment includes, in principle, a number of mutually distinct operable positions, which are also intermittently storage positions. Electrical and / or magnetic deflection means are provided to precisely couple the emitted charged particles from each of these operable positions into the illumination tube of the multibeam particle microscope. The deflection means can have a single-part or multi-part design in this context. In this modification of the embodiment of the present invention, rapid replacement or modification of particle sources is possible because the vacuum does not need to be broken, the multibeam particle microscope does not need to be evacuated again, and the baking does not need to be redone. Furthermore, the spatially fixed arrangement of particle sources makes it possible to replace particle sources without fine-tuning the particle sources themselves within the range of particle source replacement. Each particle source can, instead, be individually calibrated during the initial setup of the multibeam particle microscope. Of course, it is still possible to provide additional means for subsequent fine-tuning, as has already been described in relation to modifications of other embodiments of the present invention.

[0068] The switching mechanism for switching between particle sources may be, for example, a selection button or a selection indicator, but it is also possible to provide or implicitly integrate the switching mechanism into the controller of the multi-beam particle microscope. For example, it is possible to perform automatic switching accurately when it is deemed necessary to change the particle source.

[0069] According to a preferred embodiment of the present invention, the multibeam particle microscope comprises exactly four particle sources, the four particle sources arranged in pairs facing each other, and each particle source is positioned to emit charged particles perpendicular to the optical axis of the multibeam particle microscope. In other words, the emission of charged particles from the particle sources is not carried out directly from above in the direction of the optical axis of the multibeam particle microscope, but rather at 90° to the optical axis, i.e., to the side. In a variation of this embodiment of the present invention, the switching means comprises two pairs of Helmholtz coils, i.e., four coils in total, in each case where only one pair of Helmholtz coils is operational at any given time. Each coil is further positioned between one of the particle sources and a virtual extension of the optical axis of the multibeam particle microscope. Thus, in this situation, the sequence of particle source-one coil of the Helmholtz coil pair-virtual extension of the optical axis of the multibeam particle microscope is realized four times. The axes of the Helmholtz coil pair itself are positioned perpendicular to the optical axis (or a virtual extension of the optical axis) of the multibeam particle microscope, thereby directing the magnetic fields that each Helmholtz coil pair can generate perpendicular to the optical axis of the multibeam particle microscope. The controller is further configured to control the Helmholtz coil pair so that charged particles emitted from each operating particle source are deflected or reoriented in the direction of the optical axis of the multibeam particle microscope.

[0070] In this embodiment of the present invention, the particle source preferably comprises a cathode tip, an extractor throttling, and an anode throttling, and optionally a suppressor electrode.

[0071] According to an alternative embodiment of the present invention, the multibeam particle microscope comprises exactly four particle sources, which are arranged in pairs facing each other and each is tilted at an angle α≠0°, specifically 40°≦α≦50°, preferably α=45°, with respect to the optical axis of the multibeam particle microscope. Thus, compared to the modification of the embodiment with two pairs of Helmholtz coils described above, the four particle sources are tilted in the direction of the optical axis of the multibeam particle microscope. In this embodiment of the present invention, the deflection means comprises four deflection electrodes, each assigned to one particle source. The deflection electrodes may be identical to the four anodes of the four particle sources, but separate deflection electrodes may be provided. Specifically, the deflection electrodes can be configured as deflection electrode diaphragms. Such electrode diaphragms may be arranged parallel to, for example, the anode diaphragm or extractor diaphragm of the particle source. In a variation of this embodiment of the present invention, the controller is similarly configured to use deflection potentials to control the deflection electrodes of particle sources facing the working particle source, so that the charged particles emitted from each working particle source are deflected or reoriented toward the optical axis of the multibeam particle microscope. Furthermore, it is possible to apply voltages for lateral adjustment to two other deflection electrodes that are not assigned to the working particle source and are not assigned to the particle source directly facing the working particle source. Thus, this embodiment of the present invention also allows for the complete absence of particle source transport. Ideally, mechanical adjustment is also unnecessary within the range of particle source exchange. Instead, an electric field is used for switching and optional (fine) adjustments. Thus, this particle source exchange can also be performed very quickly and even more precisely.

[0072] The embodiments of the present invention described above can be combined in whole or in part, within the scope of one aspect of the invention and beyond, as long as no technical inconsistencies result.

[0073] The present invention will be better understood with reference to the attached figures. [Brief explanation of the drawing]

[0074] [Figure 1] This is a schematic diagram illustrating a multibeam particle microscope. [Figure 2] This is a schematic cross-sectional view showing the double sealing and lens barrel separation module. [Figure 3] This diagram schematically shows the spatial representation of the double-sealed and tube-separated modules. [Figure 4] This diagram schematically shows the illumination tube, double sealing, and tube separation module of a multibeam particle microscope. [Figure 5] This diagram schematically illustrates various arrangements of double-sealed and tube-separated modules within a multi-beam particle microscope. [Figure 6] This diagram schematically illustrates the exchange of particle sources. [Figure 7] This diagram schematically shows a portion of a multibeam particle microscope equipped with replaceable particle sources, where the replacement particle sources are located within a storage unit. [Figure 8] This diagram schematically shows a portion of a multibeam particle microscope equipped with replaceable particle sources, where the replacement particle sources are located within a storage unit. [Figure 9] This diagram schematically shows a portion of a multibeam particle microscope equipped with replaceable particle sources, where the replacement particle sources are located within a storage unit. [Figure 10] This diagram schematically shows a portion of a multi-beam particle microscope equipped with replaceable particle sources, where replacement is performed by switching. [Figure 11] This diagram schematically shows a portion of a multi-beam particle microscope equipped with replaceable particle sources, where replacement is performed by switching. [Figure 12] This diagram schematically shows a portion of a multi-beam particle microscope equipped with replaceable particle sources, where replacement is performed by switching. [Figure 13] This figure schematically shows a multi-beam particle source and the position dependence of the current intensity of the multi-beam particle source. [Figure 14]This diagram schematically illustrates the acquisition of a current pattern at an anode aperture, which can be used to precisely adjust the particle source. [Figure 15] This is a schematic plan view showing a covering element that can be inserted into the beam path. [Figure 16] This is a schematic cross-sectional view showing a covering element that can be inserted into the beam path. [Figure 17] This is a schematic cross-sectional view showing a double-sealed and barrel separation module with a filling volume. [Figure 18] This diagram schematically illustrates a foldable shield element for a sealing mechanism. [Figure 19] This diagram schematically illustrates the spatial representation of a double-sealed and barrel separation module equipped with a foldable shielding element for the sealing mechanism. [Figure 20] This diagram schematically illustrates differential pumping in the case of a double-sealed and barrel-separated module. [Modes for carrying out the invention]

[0075] Figure 1 schematically shows a multibeam particle microscope 1. The multibeam particle microscope 1 comprises a beam generator 300 equipped with a particle source 301, for example, an electron source. A diffuse particle beam 309 is collimated by a series of focusing lenses 303.1 and 303.2 and collides with a multi-aperture array 305. The multi-aperture array 305 comprises a plurality of multi-aperture plates 306 and a field lens 308. The multi-aperture array generates a number of individual particle beams 3 or individual electron beams 3. The aperture centers of the multi-aperture plate array are positioned in the field, and this field is imaged onto another field formed by a beam spot 5 on the object surface 101. The distance between the aperture centers of the multi-aperture plates 306 may be, for example, 5 μm, 100 μm, and 200 μm. The aperture diameter D is shorter than the distance between the aperture's center points, and examples of diameters are 0.2 times, 0.4 times, and 0.8 times the distance between the aperture's center points.

[0076] The multi-aperture array 305 and the field lens 308 are configured to generate a raster array of multiple focal points 323 of the primary beam 3 on the surface 321. The surface 321 does not need to be planar, but rather can be spherically curved to account for the image field curvature of the subsequent particle optics system.

[0077] The multibeam particle microscope 1 further comprises a system of electromagnetic lenses 103 and objective lenses 102, which image the beam focus 323 at a reduced size from the intermediate image plane 325 to the object plane 101. The first individual particle beam 3 passes between the intermediate image plane 325 and the object plane 101 through a beam splitter 400 and a combined beam deflection system 500, which are used to deflect a number of first individual particle beams 3 during operation, scanning the image plane. The first individual particle beams 3 incident on the object plane 101 form, for example, a substantially equilateral and equiangular field, and the distance between adjacent incident locations 5 may be, for example, 1 μm, 10 μm, or 40 μm. The field formed by the incident locations 5 may have, for example, rectangular or hexagonal symmetry.

[0078] The object 7 being examined may be any desired type of object, such as a semiconductor wafer or a biological sample, and may comprise an array of miniaturized elements. The surface 15 of the object 7 is positioned on the object surface 101 of the objective lens 102. The objective lens 102 may include one or more electro-optical lenses. The objective lens 102 may be, for example, a magnetic objective lens and / or an electrostatic objective lens.

[0079] Primary particles 3 incident on the object 7 generate interaction products, such as secondary electrons, backscattered electrons, or primary particles that have moved backward for other reasons. These interaction products are emitted from the surface of the object 7 or from the first plane 101, i.e., the object surface 101. The interaction products emitted from the surface 15 of the object 7 are shaped by the objective lens 102 to form a secondary particle beam 9. In this process, the secondary beam 9 passes through a beam splitter 400 located downstream of the objective lens 102 and is fed to the projection system 200. The projection system 200 comprises an imaging system 205 with projection lenses 208, 209, and 210, a contrast diaphragm 214, and a multi-particle detector 207. The incident locations 25 of the second individual particle beam 9 on the detection area of ​​the multi-particle detector 207 are arranged at regular intervals in the third field. Exemplary values ​​are 10 μm, 100 μm, and 200 μm.

[0080] The multibeam particle microscope 1 may have a single-part or multi-part design and further comprises a computer system or control unit 10 designed to control the individual particle optical components of the multibeam particle microscope 1, as well as to evaluate and analyze signals obtained from the multi-detector 207 or detection unit.

[0081] Further information relating to such multi-beam particle beam systems or multi-beam particle microscopes 1, as well as components used therein, such as particle sources, multi-aperture plates, and lenses, can be obtained from International Patent Applications 2005 / 024881, 2007 / 028595, 2007 / 028596, 2011 / 124352, and 2007 / 060017, as well as German Patent Applications 102013016113 and 102013014976, the disclosures thereof being fully incorporated into this application by reference.

[0082] Figure 2 schematically shows a cross-sectional view of a double-sealing and tube separation module 710, which may be incorporated into the multibeam particle microscope shown in Figure 1. The double-sealing and tube separation module 710 is positioned in the illumination tube of the multibeam particle microscope 1. In this case, Figure 2 shows only a portion of the illumination tube. A housing 708 with a first beam tube section 704 and a housing 709 with a second beam tube section 705 are shown. The beam tube 703 is subdivided into two beam tube sections 704 and 705 by the double-sealing and tube separation module 710. The double-sealing and tube separation module 710 is positioned in a sealed state between the two beam tube sections 704 and 705 during operation of the multibeam particle microscope 1 or while installed, and charged particles or a first individual particle beam 3 (charged particles and the first individual particle beam 3 are not explicitly shown in Figure 2) pass through the double-sealing and tube separation module. Figure 2 shows, as an example, a sealing surface 706 for a sealed array. In this case, the objective is to ensure the high vacuum required for the operation of the multibeam particle microscope, even in the mounted double-seal and barrel separation module 710. The double-seal and barrel separation module 710 is spatially separable into a first submodule 711 and a second submodule 712 when the multibeam particle microscope 1 is not operating. For this purpose, the double-seal and barrel separation module 710 is preferably accessible from the outside, and as a result, the first submodule 711 and the second submodule 712 are spatially separable, for example, by unscrewing a screw connection. An intermediate member or adapter 713 can be placed between the first submodule 711 and the second submodule 712. However, this adapter 713 can also be part of the second submodule 712, indicated by reference numeral 712' in Figure 2 (see also Figure 4b). The first submodule 711 includes a first sealing element 714 configured to shield the adjacent beam tube portion 704 on the particle source side in a sealed state when the first submodule 711 and the second submodule 712 are spatially separated.The second submodule 712 includes a second sealing element 715 configured to seal the adjacent beam tube portion 705 on the beam splitter side when the first submodule 711 and the second submodule 712 are spatially separated. The sealing elements 714 and 715 are shown in the closed position in Figure 2. As a result, each beam tube 703 is vacuum-sealed by the components of the sealing elements 714 and 715. The sealing elements in the narrow sense are indicated by reference numerals 714a and 715a in Figure 2. In this case, the sealing elements 714 and 715 can be implemented in various ways. For example, the first sealing element 714 and / or the second sealing element 715 of the double sealing and beam tube separation module 710 may comprise an ultra-high vacuum slider, a flap valve, or a pendulum valve. Other embodiments of the first sealing element 714 and / or the second sealing element 715 are also possible. In this case, the first sealing element 714 and / or the second sealing element 715 can be configured to operate manually, pneumatically, or electrically. The double sealing and barrel separation module 710 is, according to one example, 10. -10 It is configured to achieve mbar or better ultra-high vacuum. The double sealing and barrel separation module 710, as an example, is also, or alternatively, 10 -9 It is configured to achieve a leakage rate of less than mbar / l / second.

[0083] The double-sealed and barrel separation module 710 includes a passage 717 in an intermediate region 716 between the first sealing element 714 and the second sealing element 715 to achieve vacuum or high vacuum during operation. The intermediate region 716 is thus evacuable to operate the multibeam particle microscope 1, and the vacuum in the intermediate region 716 can be broken to separate the first sub-module 711 and the second sub-module 712 (see also Figure 4b). In the example shown in Figure 2, the passage 717 is realized by a simple drilled hole. However, it is also possible to realize multiple drilled holes or a passage designed differently. In the example shown, the drilled hole 717 is connected to a vacuum airtight conduit 718. The vacuum airtight conduit 718 can or may be connected to a vacuum pump (not shown).

[0084] Figure 17 schematically shows a cross-sectional view of a double-sealed and tube-separated module 710 equipped with a filling volume 707. This filling volume 707 plays a role in reducing the volume below the double-sealed and tube-separated module 710 that should create a vacuum. The filling volume 707 may contain or be made of titanium, for example. Furthermore, an advantage of the filling volume 707, specifically a filling volume containing or made of titanium, is that it functions as a barrier that precisely prevents the propagation of scattered radiation or scattered electrons in both the second sub-module 712 of the double-sealed and tube-separated module 710 and the region or module of the multi-beam particle microscope 1 located below the second sub-module 712 in the direction of the particle light beam path. The charging of the sealing mechanism can also be reduced. In the example shown, the filling volume 707 has a through-hole whose diameter d2 is smaller than the diameter d1 of the beam tube 703. This dimensional setting also contributes to the reduction of scattered radiation.

[0085] Figure 3 schematically shows the spatial representation of the double-sealed and tube-separated module 710. In the example shown, the housings 708 and 709 of the illumination tube are substantially tubular. The beam tube portions 704 and 705 of the beam tube 703 are located within the housings 708 and 709, respectively. However, the actual beam tube portions 704 and 705, which continue within the illumination tube to the particle source side and the beam splitter side, respectively, are not explicitly shown in this way in Figure 3 for clarity. Instead, Figure 3A shows, as an example, the basic mechanism of the double-sealed and tube-separated module 710 and its integration into the illumination tube in a perspective view. The first sub-module 711 of the double-sealed and tube-separated module 710 is located in contact with the housing 708 and further in contact with the beam tube 703 located within the housing 708 or the beam tube portion 704 located within the housing 708. In this case, the connection between the housing 708 and the first submodule 711 is flange-like, and Figure 3 shows a sealing surface 706 as an example. Thus, the quality of the resulting sealing mechanism or sealing surface is particularly important, especially in the area of ​​the beam tube 703. The second submodule 712 is connected to the first submodule 711 via another sealing surface 706. The second submodule 712 is then sealed to the housing 709, or to the beam tube 703 or associated beam tube section 705 located within the housing 709. In the example shown, the first sealing element 714 and the second sealing element 715 are realized by ultra-high vacuum sliders. To achieve vacuum hermetically sealed closure, sections 714a and 715a are sealed, for example, by pushing or sliding them into the intermediate region 716 within the double sealing and tube separation module 710. This can be clearly seen, in particular, in Figure 3B, which shows a cross-sectional view of the double sealing and tube separation module 710. The double-sealing and barrel separation module 710 has a passage 717 in the form of a drilled hole in an intermediate region 716 between the first sealing element 714 and the second sealing element 715. A vacuum airtight conduit (not shown) can be connected to this drilled hole 717, which can then be connected to or connected to a vacuum pump (not shown).In this case, the passage 717 itself is incorporated in the first partial module 711 in the example shown. However, it is also possible to arrange the passage 717 not in the first partial module 711 but, for example, in an intermediate member or adapter between two partial modules 711 and 712. If the individual components or modules provided in the double-sealing and lens barrel separation module 710 are as few as possible, this is advantageous in principle because it enables a more appropriate handling of the sealing problems regarding the generation and maintenance of an ultra-high vacuum. In contrast, the argument for the adapter member may be that the adapter member enables the production of the first partial module 711 and the second partial module 712 with the same structure.

[0086] The double-sealing and lens barrel separation module 710 is electrically conductive and has a relative magnetic permeability μ r of μ r ≤ 1.005, or may include or be composed of a material that satisfies this. As a result, during the operation of the multi-beam particle microscope, the particle beam passing through the double-sealing and lens barrel separation module 710 is not obstructed, and the double-sealing and lens barrel separation module is not charged or magnetized. For this reason, in order to avoid possible charging of the sealing surface 706, it is also advantageous to slightly recess the region of the intermediate region 716, that is, the sealing surface 706 arranged inside the double-sealing and lens barrel separation module 710, from the cavity 716 or to mask the sealing surface.

[0087] Figure 18 schematically shows foldable shield elements 722, 723 for the sealing mechanism 726. For example, the sealing mechanism 726 may include a fluororubber or fluoroelastomer known, for example, by trade name Viton®. The use of a sealing mechanism 726 made of a fluororubber or fluoroelastomer, such as Viton®, is advantageous because the contact pressure is lower than when a metal sealing mechanism is required for the sealing process. Such a sealing mechanism is also relatively soft and flexible, which reduces the requirements for mechanical tolerances and surface roughness in the sealing area. The shield elements 722, 723 are made of metal. The foldable shield elements 722, 723 include an upper region 724 and a side region 725, resulting in the formation of a housing or a kind of garage for the sealing mechanism 726. The shield elements 722, 723 are closed when the valves of the double sealing and barrel separation module 710 are open, or when the multibeam particle microscope 1 is operated under vacuum (see Figure 18a). Therefore, the sealing mechanism 726 can be protected from static charge during operation. Any scattered radiation that may occur, such as scattered electrons, can be captured and redirected by the metal shielding elements 722 and 723. The sealing mechanism 726 is positioned without restriction outside the shielding elements 722 and 723 only when used for double sealing and barrel separation. The shielding elements 722 and 723 are open when the valve of the double sealing and barrel separation module 710 is closed, or when the double sealing and barrel separation module 710 is separated into the first submodule 711 and the second submodule 712, or should be separated (see Figure 18b).

[0088] Figure 19 schematically shows a spatial representation of the double-sealed and barrel separation module 710, which includes foldable shielding elements 722 and 723 for a sealing mechanism 726 (not explicitly shown in Figure 19). The housing or garage characteristics of the foldable shielding elements 722 and 723 are readily apparent in the spatial representation.

[0089] Figure 20 schematically illustrates differential pumping in the case of a double-sealed and barrel separation module 710. When a sealing mechanism 726 made of fluororubber or fluoroelastomer is used for the separation surface T of the double-sealed and barrel separation module 710, this sealing mechanism 726 has very good sealing properties, but still has a higher leakage rate than a metal sealing mechanism. This high leakage rate can lead to an increase in the final pressure of the UHV. To minimize or ideally eliminate this problem, it has been proposed to use differential pumping at the separation surface T, which reduces the pressure gradient and thus the leakage rate. For this purpose, another sealing mechanism 727 is provided, which may be made of the same material as the sealing mechanism 726. As a result, at least one additional pressure stage is created, having a volume V2 located in the region between the two sealing mechanisms 726 and 727, in addition to the volume V1 that is vacuum-evacuated. Volume V1 is connected to a pump (not shown) via conduit 729, and volume V2 is connected to a pump (not shown) via conduit 728. Volumes V3 and V4 are schematically shown and are assigned to vacuum-evacuated volumes above and below the double-sealed and tube isolation module 710, respectively, within the lens barrel.

[0090] Figure 4 schematically shows a schematic representation of the illumination tube 700 of the multibeam particle microscope 1, as well as the double-sealed and tube separation module 710. In this case, the housings 708 and 709 of the illumination tube 700 are simply shown schematicly as outlines. The particle optical system is located within the housing, as has already been described in considerable detail in relation to Figure 1. Substantial, the order of the particle light components within the illumination tube 700 is such that, for example, the particle source 301 is located at the top within the illumination tube 700 or within the housing section 708. In the example shown, a focusing lens system, for example, comprising two magnetic focusing lenses 303.1 and 303.2, is located below the particle source 301. The multibeam generator 305 is located below the focusing lens system in the particle light beam path. Next, below the multibeam generator 305, is the first field lens 308, followed by another field lens 103. The beam splitter 400 is located even further down within the particle light beam path.

[0091] There are several options regarding the placement of the double-sealing and tube separation module 710 within the illumination tube 700. Figure 5 schematically shows various possible arrangements of the double-sealing and tube separation module 710 within the multibeam particle microscope 1 or the illumination tube 700.

[0092] According to the exemplary embodiment shown in Figure 5A, the double sealing and barrel separation module 710 is located within the focusing lens system 303, i.e., between the first, specifically magnetic focusing lens 303.1 and the second, specifically magnetic focusing lens 303.2. The illumination barrel 700 is thus subdivided into the head of the illumination barrel 701 and the remaining illumination barrel 702 or the remaining barrel 702. The head of the illumination barrel 701, which always also includes the particle source 301, in this case forms the replacement module 701. The arrangement of the double sealing and barrel separation module 710 in the shown position is particularly space-saving because a drift path is provided between the two, specifically magnetic focusing lenses 303.1 and 303.2. By locating the double sealing and barrel separation module 710 within this drift path, mounting space or barrel height is saved.

[0093] In the exemplary embodiment shown in Figure 5B, the double sealing and barrel separation module 710 is positioned between the focusing lens system 303 and the multibeam generator 305. While the focusing lens system in the shown example comprises two focusing lenses 303.1 and 303.2, it may, of course, comprise three or more focusing lenses. The exemplary embodiment shown is advantageous because it allows for more extensive pre-configuration or pre-adjustment of the replacement module 701. This specifically relates to complete pre-adjustment of the entire particle source 301 and focusing lens system 303.

[0094] According to the exemplary embodiment shown in Figure 5C, the double sealing and barrel separation module 710 is located further below the illumination barrel 700. The double sealing and barrel separation module 710 is specifically located between the first field lens 308 and the second field lens 103 of the field lens system. In a variation of this embodiment, the replacement module 701 is slightly larger than in the example shown in Figures 5A and 5B. This allows for pre-examination or pre-adjustment of more components of the replacement module 701 before the replacement of the particle source 301. Specifically, it is possible to optimally pre-set the incidence of charged particles to the multibeam generator 305 even before the replacement of the particle source 301. As a result, time is saved during the actual replacement of the particle source 301. However, this comes at the cost of more materials and manufacturing costs. Nevertheless, after the replacement of the particle source 301, one or more components of the replacement module 701 can be reused or modified for the new replacement module 701.

[0095] In the example shown in Figure 5, the total height h of the double-seal and barrel separation module 710, measured along the optical axis of the multibeam particle microscope 1 when installed, satisfies the following relationship: h ≤ 8.0 cm, preferably h ≤ 7.0 cm or h ≤ 6.0 cm. In this case, the double-seal and barrel separation module 710 has, by design, a minimum height h of, for example, about 5.0 cm to ensure the necessary stability and airtightness of the double-seal and barrel separation module 710.

[0096] Furthermore, in all the modifications of the embodiments shown in Figure 5, it is a fact that the particularly sensitive microoptics of the multibeam generator 305 are adequately protected during the replacement of the particle source 301. In the exemplary embodiments of Figures 5A and 5B, the lower sealing element 715 is closed before the particle source 301 is replaced or the replacement module 701 is removed. Thus, the multibeam generator 305 or the microoptics located within the multibeam generator 305 remains in a protective vacuum during replacement. Then, again, in the modification of the embodiment of Figure 5C, since the multibeam particle generator 305 is a component of the replacement module 701, the problem of contamination of the microoptics or the multibeam particle generator 305 does not arise.

[0097] Figure 6 schematically illustrates the replacement of the particle source 301. In this case, the particle source 301 is located in the replacement module 701.1. Other components of the illumination tube 700 can also be located in the replacement module 701.1. In this regard, Figure 6 only shows the replacement method and does not show the specific configuration of the replacement module 701.1, as shown in Figures 5A to 5C, for example. In this case, the illumination tube 700 is separated into the replacement module 701.1 and the remaining illumination tube 702 by the double sealing and tube separation module 710. In Figure 6A, the double sealing and tube separation module 710 is already spatially separated into two sub-modules, in particular the first sub-module 711.1 and the second sub-module 712. The arrows in Figure 6A indicate the spatial separation of the two sub-modules 711.1 and 712 in this case. Each of the two sealing elements 714.1 and 715 is closed during the separation procedure itself, and as a result, a high vacuum can be maintained therein in both the replacement module 701.1 and the remaining lens barrel 702. The double seal and the vacuum in the intermediate region 716 of the lens barrel separation module 710 were broken before separation, precisely through the passage that has already been described in relation to the previous figure. In the example shown, a portion of the intermediate region, or the adapter member including the passage and supply conduit 718, remains located on the remaining lens barrel 702, or remains located on the second partial module 712, or in either case has an embodiment that is integrated with the second partial module 712.

[0098] Once the replacement module 701.1 is removed from the remaining illumination tube 702, the replacement particle source 301.2 can then be taken from the storage unit 720 and placed in the remaining illumination tube 702 in place of the original module 701.1. Figure 6B illustrates this procedure.

[0099] In the example shown, the storage unit 720 has three storage spaces for three replacement modules 701.2, 701.3, and 701.4. Each storage space contains a new, i.e., unused particle source 301.2, 301.3, and 301.4. Each of the replacement modules 701.2, 701.3, and 701.4 has been pre-screened and / or pre-adjusted. The replacement modules 701.2, 701.3, and 701.4 have also been pre-vacuumed and are stored inside or on the storage unit 720 with their sealing elements 711, 712 open. In this process, the interior 721 of the storage unit 720 is vacuumed using a vacuum pump 719.

[0100] Here, for example, before removing the replacement module 701.2 from the storage chamber, the two sealing elements 714.2 and 715.2 are closed. The vacuum in the intermediate region between the two sealing elements 714.2 and 715.2 is broken, and as a result, the replacement module 701.2 can now be removed from the storage chamber 720 without any problems. The replacement module 701.2 can then be immediately transported to the remaining illumination tube 702 and placed on the remaining tube 702. The arrows in Figure 6B further illustrate these movements. In this case, the first sub-module 711.2 of the second replacement module 701.2 has the same structure as the first sub-module 711.1 of the old replacement module 701.1. Therefore, the first sub-module 711.2 fits snugly into the second sub-module 712, and as a result, the new double-sealed and tube separation module 710 can be assembled from that situation. After the replacement module 701.2 is placed on the remaining barrel 702, the intermediate region 716 between the first sealing element 714.2 and the second sealing element 715 is first evacuated. The intermediate region 716 can then be baked out, for example, using a heating element (not shown in the figure) located within the double sealing and barrel separation module 710. After this relatively short vacuum evacuation and optional bake-out of the double sealing and barrel separation module 710, the sealing elements 714.2 and 715 can then be opened again.

[0101] Ideally, the arrangement of the second replacement module 701.2 onto the remainder of the multibeam particle microscope 1 or the remaining tube 702 is performed isotropically. In this case, no further adjustment of the replacement module 701.2 to the remaining tube 702 is required. In addition, or alternatively, the adjustment of the second replacement module 701.2 can be performed using adjustment components. In addition, or alternatively, the second replacement module 701.2 can be adjusted using an electric and / or magnetic deflection field to deflect charged particles and / or the charged first individual particle beam. After these adjustment steps, the multibeam particle microscope 1 becomes operational with the new particle source 301.2.

[0102] In principle, the replacement of the particle source 301 located within the replacement module 701, as described, can be repeated until all replacement modules 701 stored in the storage unit 720 have been installed. Furthermore, it is naturally possible to fill any available storage space in the storage unit 720 with new replacement modules 701 that have been pre-screened and pre-adjusted. In this way, replacement modules equipped with new particle sources 301 are always available. Moreover, it is naturally possible to store replacement modules 701 for multiple multibeam particle microscopes 1 in the storage unit 720.

[0103] Figure 7 schematically shows details of a multibeam particle microscope 1 with interchangeable particle sources. The illumination tube 700 of the multibeam particle microscope 1 comprises a first vacuum region 730, which includes a first particle source 301.1 located at a movable position 731 within the illumination tube. The first particle source 301.1 is therefore positioned and configured to emit charged particles to operate the multibeam particle microscope 1. Similarly in the modifications of this embodiment of the present invention, a plurality of interchangeable particle sources 301.2, 301.3, and 301.4 are pre-examined and / or pre-adjusted. The interchangeable particle sources are located in a storage unit 741 which includes a number of storage positions 742.1, 742.2, 742.3, and 742.4. The storage unit 741 is in this case located within a vacuum region 740. A vacuum pump 719 can be used to create a high vacuum or ultra-high vacuum in this vacuum region 740.

[0104] Furthermore, a transport mechanism is provided for vacuum transporting replacement particle sources 301.2, 301.3, and 301.4 from the storage unit 741 in the second vacuum region 740 to an operational position 731 within the first vacuum region 730. As a result, pre-configured replacement particle sources 301.2, 301.3, and 301.4, which are structurally identical to the first particle source 301.1, can be transported to the operational position 731 as needed and, consequently, can function as the working particle source 301. The transport mechanism can have a single-part or multi-part design and can be implemented in various technical ways. In the example shown, the transport mechanism comprises two transport rods 743 and 744. The storage unit 741 can be displaced in the z direction by the movement of the transport rods 744 within the second vacuum region 740. As a result, the particle source 301 intended for replacement can be moved, in a narrow sense, to the z position required for transport. For example, in the example shown, the transport rod 743, which allows displacement in the x-direction, can be used to transport a replacement particle source from the second vacuum region 740 to the first vacuum region 730. A stage of the illumination tube 700 that is displaceable in the z-direction can be a further component of the transport mechanism. As a result, the operable position 731 of the working particle source 301.1 can be displaced in the z-direction and, if necessary, adapted to the transport or transfer position of the replacement particle source. In the example shown, the first vacuum region 730 and the second vacuum region 740 are designed as separate vacuum chambers 730, 740. In the example shown, an ultra-high vacuum slider 745, which is opened while the particle source 301 is being transported, is located between the two regions 730 and 740, or between the chambers 730 and 740. However, it is also possible to form the two vacuum regions 730, 740 as a common vacuum chamber without a gate and slider between the two regions 730 and 740. It is preferable that the transport mechanism is further configured to vacuum transport the first particle source 301.1 from an operable position 731 in the first vacuum region 730 to a storage unit 741 in the second vacuum region 740.For example, the same transport rod 743 can be used to both place the replacement particle source 301 into the illumination tube 700 and to remove the replacement particle source from the illumination tube 700 again.

[0105] A key feature of this modified embodiment of the present invention is that the pre-examined replacement particle sources 301.2, 301.3, and 301.4 are pre-positioned within a vacuum region directly or indirectly connected to the vacuum region 730 of the illumination tube. Therefore, no separate storage unit for the replacement particle sources or complete replacement modules is provided. As a result, the replacement unit can be smaller than that of the replacement module 701 in the modified embodiments of the present invention described in Figures 2 to 6. The replacement particle source 301 can also be said to be pre-integrated into the multibeam particle microscope 1.

[0106] In the exemplary embodiment shown in Figure 7, the storage unit 741 has a plurality of storage positions 742.1, 742.2, 742.3, and 742.4 arranged according to a physically linear topology. In this case, the storage positions 742 are arranged vertically in the z direction and are transported to the transport position by linear displacement, i.e., displacement in the z direction. An alternative, physically linear topology can also be designed such that the storage positions 742 are arranged continuously in the x direction. In this way, the replacement particle source 301 can be continuously transported to the operational position 731 and then moved again to the opposite side from the illumination tube 700.

[0107] Figure 8 schematically shows a further embodiment of the invention, a modified multibeam particle microscope with a replaceable particle source 301. In this modified embodiment, the replaceable particle source 301 is also located in a storage unit 741. This storage unit 741 is located in a vacuum region 740. In the example shown, the vacuum region 740 is formed integrally with a vacuum region 730 in which the particle source 301.1 is located at the operational position 731. In this case, Figure 8 shows a schematic plan view of the working particle source 301.1 and the replaceable particle sources 301.2-301.5 in the storage unit 741.

[0108] The embodiment shown in Figure 8 differs from the embodiment shown in Figure 7 in terms of the topology of the storage unit 741 in which the storage position 742 is located. According to a modification of the embodiment in Figure 8, the storage unit 741 has a plurality of storage positions 742.1 to 742.5 arranged according to a physically star-shaped topology. In the example shown, the storage positions 742.1 to 742.5 are arranged in a ring. In this case, each of the replacement particle sources 301.1 to 301.5 can be transported to an operational position 731 by movement toward the center of the circle, i.e., by star-shaped movement. This movement is radial r movement, schematically shown by double arrows in Figure 8. As a further example, the first particle source 301.1 is transported from its storage position 742.1 to an operational position 731 by radial movement using a transport rod 743.1.

[0109] Again, in this modified embodiment of the present invention, the replacement of the particle source 301 from the storage unit 741 at the operational position 731 is carried out in a complete or high vacuum. There is no need to first break the vacuum and then re-establish it. As a result, the replacement of the particle source 301 can be achieved much more quickly, and contamination of the vacuum areas 730, 740 is generally avoided. The multibeam particle microscope 1 actually only needs to be opened when all the replacement particle sources 301.2-301.5 have been used or consumed, and for this, of course, the vacuum must be broken again. Again, in that case, it is possible to immediately equip the multibeam particle microscope 1 with a number of particle sources 301, each of which has been pre-screened and / or pre-adjusted. Thus, the time required for the replacement of the particle source 301 is also greatly reduced overall.

[0110] Figure 9 shows a further exemplary embodiment of the multibeam particle microscope 1, equipped with a replaceable particle source 301. In this case, Figure 9A shows a schematic cross-sectional view, and Figure 9B shows a schematic plan view. Again, this modification of the embodiment of the present invention differs in topology from the exemplary embodiment described in Figures 7 and 8. A storage unit 741 is provided having a plurality of storage positions 742.2 to 742.6 for the replaceable particle sources 301.2 to 301.6, the storage positions being arranged according to a physically ring-shaped topology. The operable position 731 of the working particle source 301.1 is similarly located on this ring or ring. In the example shown, this physically ring-shaped topology is realized using a rotary conveyor 746. The physically ring-shaped topology can also be called a swivel-type topology. The rotary conveyor 746 in this case comprises a rod or coupling 750, and the rotary conveyor 746 is rotatable around a rotation center 747. This makes it possible to rotate the replacement particle sources 301.2 to 301.6 to the operable position 731.

[0111] A contact unit 748, equipped with electrical contacts 749.1 to 749.3, is also shown as an example in this embodiment of the present invention. This contact unit 748 plays a role in electrically contacting each of the operating particle sources 301 at a movable position 731. This may involve, for example, elastic sliding contacts for establishing an electrical connection (see Figure 9B). Alternatively, the contact unit 748 may be movable in the Z direction using a Z-stage, so that the contact unit 748 can be connected to each of the operating particle sources 301 like a connector. In this situation, it should be noted that these contacts 749.1, 749.2, and 749.3 are contacts that can be used for high-voltage applications. For example, the tip cathode, lead-out throttling, and anode throttling of the particle source 301 can be in contact via contacts 749.1, 749.2, and 749.3.

[0112] In all the modifications of the embodiments shown in Figures 7 to 9, an adjustment unit may optionally be provided for precisely positioning each operating particle source 301 at an operable position 731. Again, in this context, the adjustment unit may have a single-part or multi-part design. The adjustment unit can be implemented, for example, by a 3D stage and / or by a piezoelectric element. Other embodiments are also possible.

[0113] In general, in the modified embodiments of the present invention shown in Figures 7 to 9, each replacement particle source 301 comprises a tip cathode, an extractor electrode, and an anode, which are pre-adjusted relative to each other and / or technically pre-examined. As a result, in these modified embodiments, it is possible to avoid, with little or no relative fine-tuning between the components of the replacement particle source 301, which saves time.

[0114] Figure 10 schematically shows a portion of a multibeam particle microscope 1 equipped with a replaceable particle source 301, the replacement of which is performed by switching. According to this embodiment of the present invention, the multiple structurally identical particle sources 301.1 to 301.4 have a spatially fixed arrangement. Therefore, there is no need to transport or move the particle source 301 from a storage position to an operational position. The transport mechanism is replaced by a switching means configured to switch between the particle sources 301.1 to 301.4, so that at any given time, exactly one of the particle sources 301.1 to 301.4 is the working particle source emitting charged particles 309. In this case, the controller 10 of the multibeam particle microscope 1 is configured to control the switching means for switching. This is because the control of the particle sources 301.1 to 301.4 is involved, ensuring that at any given time, exactly one of the particle sources 301 is the working particle source 301.1.

[0115] In order to ensure that charged particles 309 emitted from each of the particle sources 301.1 to 301.4, or from each operable position, are precisely coupled to the illumination tube 700 of the multibeam particle microscope 1, this embodiment of the present invention includes electrical and / or magnetic deflection means configured to deflect charged particles 309 emitted from each operating particle source 301.1 onto the optical axis 350 of the multibeam particle microscope 1. In this case, the controller 10 of the multibeam particle microscope 1 is also configured to control the deflection means.

[0116] In the exemplary embodiment shown in Figure 10, the multibeam particle microscope 1 comprises exactly four particle sources 301.1 to 301.4, which are arranged in pairs facing each other, and each of the particle sources 301.1 to 301.4 is positioned to emit charged particles 309 perpendicular to the optical axis 350 of the multibeam particle microscope 1. In the plan view of Figure 10A, the optical axis is oriented in the plane of the drawing, and the optical axis 350 extends in the z direction. In the example shown, particle sources 301.1 and 301.3 are also paired and arranged facing each other. The corresponding description also applies to particle sources 301.2 and 301.4. In this case, of course, all particle sources 301.1 to 301.4 are located in a vacuum or high vacuum.

[0117] In the exemplary embodiment shown in Figure 10, the deflection means comprises two pairs of Helmholtz coils 344, 345, thus a total of four coils 344.1, 344.2, 345.1, and 345.2, in which at any given time only one pair of Helmholtz coils 344, 345 is operational. In this case, coils 344.1, 344.2, 345.1, and 345.2 are positioned between one of the particle sources 301.1 to 301.4 and the optical axis 350 of the multibeam particle microscope 1 or a virtual extension of the optical axis 350. In this case, since the axes of the two pairs of Helmholtz coils 344, 345 are positioned perpendicular to the optical axis 350 of the multibeam particle microscope 1, the magnetic field B that can be generated by either pair of Helmholtz coils 344, 345 is directed perpendicular to the optical axis 350 of the multibeam particle microscope 1. In this case, the controller 10 is configured to control the Helmholtz coil pairs 344 and 345 so that the charged particles 309 emitted from the respective operating particle sources 301 are deflected in the direction of the optical axis 350 of the multibeam particle microscope 1.

[0118] In the example shown in Figure 10A, particle source 301.1 emits charged particle 309 as an active particle source. The charged particle 309 passes through the opening of coil 344.1 of Helmholtz coil pair 344, in which case Helmholtz coil pair 344 is not active. Instead, Helmholtz coil pair 345, which has two Helmholtz coils 345.1 and 345.2, is active, and as a result the emitted charged particle 309 is subjected to a magnetic field B that is orthogonal to the emission direction of the charged particle 309 and also orthogonal to the optical axis 350 of the multibeam particle microscope 1. The charged particle 309 is deflected in a circular orbit. In the example shown, the charged particle 309 follows a quarter-circle arc. This is shown in Figure 10B, which shows a side view of the particle source region or the head of the multibeam particle microscope 1. After being deflected by 90°, the charged particle 309 leaves the magnetic field of the Helmholtz coil pair 345 in the example shown and passes through the aperture 346 having an aperture 347. The orientation of the charged particle 309 is here parallel to the optical axis 350, i.e., the z direction. The charged particle 309 then reaches a focusing lens system or collimation lens system 303 (not shown in Figure 10).

[0119] Here, for example, if there is a switch between particle source 301.1 and particle source 301.2, particle source 301.2 becomes the active particle source and particle source 301.1 becomes inactive. Furthermore, Helmholtz coil pair 345 is stopped and Helmholtz coil pair 344 becomes active instead. Similar procedures can be performed for replacement particle sources 301.3 and 301.4.

[0120] Figure 11 shows a modification of a further embodiment of the present invention, in which the replacement of particle source 301 is similarly carried out by switching rather than mechanical transport. The exemplary embodiment shown in Figure 11 differs substantially from the exemplary embodiment shown in Figure 10 by the design of the deflection means. In the modification of the embodiment according to Figure 11, an electric deflection means is used. Furthermore, the arrangement of particle sources 301.1 to 301.4 is slightly different from the arrangement in Figure 10. This is because the particle sources 301.1 to 301.4, which face each other in pairs, are each inclined at an angle α with respect to the optical axis 350 of the multibeam particle microscope 1. Figure 11B best illustrates this, and a schematic side view is shown in Figure 11B. The particle sources 301.1 and 301.3, which face each other in pairs, are inclined at approximately 45° with respect to the optical axis 350 of the multibeam particle microscope 1. However, the angle α can be slightly larger or slightly smaller, for example, 40° ≤ α ≤ 50°. In the example shown, the deflection means comprises four deflection electrodes corresponding to the four anodes 343.1 to 343.4 of the four particle sources 301.1 to 301.4 in the example shown. However, it is also possible to provide the four deflection electrodes separately, i.e., separate them from the four anodes 343.1 to 343.4 of the four particle sources 301.1 to 301.4. The controller 10 is configured to use the deflection potential to control the deflection electrodes of the particle sources 301, each facing the working particle source 301, so that the charged particles emitted from each working particle source 301 are deflected in the direction of the optical axis 350 of the multibeam particle microscope 1. In the example shown in Figure 11, particle source 301.1 is in the working state. In the example shown, particle source 301.3, having the same deflection electrode 343.3 as the anode of particle source 301.3, faces the working particle source. The function of the deflection electrode as deflection electrode 343.3 is obtained by control corresponding to particle source 301.3, i.e., in the exemplary case described, only the anode 343.3 of particle source 301.3. In Figures 11A and 11B, the deflection potential is indicated by a negative sign in front of anode 343.3. Modifications of the embodiment shown in Figure 11 are otherwise identical to those shown in Figure 10.The charged particles 309, deflected along the optical axis 350, pass through the aperture 347 of the diaphragm 346 and proceed along the path of the charged particles to the light condenser 303.

[0121] Figure 12 schematically illustrates a modification of a further embodiment of the present invention of a multibeam particle microscope 1 with a replaceable particle source 301, again, the replacement being performed by switching. The exemplary embodiment shown in Figure 12 differs from the exemplary embodiment shown in Figure 10 due to the position of the focusing lens system 303. In the modification of the embodiment according to Figure 12, the focusing lens system 303 is positioned further up, i.e., pre-mounted before the charged particles 309 are coupled to the (common) optical axis 350 of the multibeam particle microscope 1. The charged particles 309 pass pre-through the first magnetic lens 303.1a of the focusing lens system before the emitted charged particles 309 enter the magnetic field of the deflection means, i.e., the Helmholtz coil pair 345. The second magnetic focusing lens 303.2 is positioned downstream of the deflection means 344, 345 and is centered on the optical axis 350. Therefore, in this embodiment of the present invention, each particle source 301.1 is further provided with magnetic focusing lenses 303.1a to 303.1d (i.e., four additional magnetic lenses) specifically assigned to this particle source. The embodiment of the present invention shown in Figure 12 therefore saves even more space than the modified embodiment shown in Figure 10.

[0122] Figure 13 schematically shows a multibeam particle source 301 and the position dependence of the current intensity of the multibeam particle source 301. In the example shown, the particle source 301 is constructed as follows: The particle source 301 comprises a cathode tip 340 whose outer surface is surrounded by a cylindrical suppressor electrode 341, which serves to suppress the lateral emergence of electrons from the cathode tip 340. The cathode tip 340 can be, for example, a thermal field emitter operating with a heating current of several amperes. A voltage of several hundred volts is applied to the cathode tip 340 at the suppressor 341. A voltage of several kilovolts is applied to the cathode tip 340 at the extractor electrode 342, which is located away from the cathode tip 340. The anode 343 is located below the extractor 342, i.e., about 1 centimeter below the cathode tip 340. The accelerating potential between the tip 340 and the anode 343 is tens of thousands of kilovolts, for example, 25kV, 30kV, or 35kV. The focusing lens system, equipped with magnetic focusing lenses 303.1 and 303.2, is located downstream of the particle source 301 in the particle light beam path. The focusing lens system shapes the collimated particle beam 311, which is then incident on the first plate (filter plate) of the multibeam generator 305 (only a cross-section is shown in Figure 13A).

[0123] In the exemplary embodiment shown, the anode 343 is designed as an anode aperture 348 with the anode aperture 348 at its center. A portion of the beam cone 310 emitted from the tip 340 is blocked by the aperture 348.

[0124] Figure 13B shows the current intensity of emitted charged particles in a cross-sectional view through the optical axis 350. In this situation, curve 351 represents the current intensity of a new particle source 301, while curve 352 represents the curve of the old particle source 301 that will be replaced. In the case of the new particle source 301, i.e., curve 351, a plateau region 353 exists. The current intensity is very uniform in this region, and therefore this plateau 353 can be very conveniently used to generate a large number of individual particle beams with the same beam current density. For this reason, the plateau 353 should ideally coincide with the aperture region 348 of the anode aperture 343. In the example shown, the teeth 354 of curve 351 are blocked by the anode aperture 343. Here, if the cathode tip 340 is not in the optimal position, i.e., not precisely on the optical axis 350, then curve 351 will also be displaced relative to the optical axis 350. Therefore, if a specific sensor system is provided on the anode aperture 343, spatially resolved measurements of the current intensity can determine whether the cathode tip 340 is precisely aligned with respect to the optical axis 350 and / or with respect to the center of the anode aperture 348. Based on such current pattern measurements, the corresponding alignment of the cathode tip 340 can then be readjusted or fine-tuned. For example, the cathode tip 340 can be displaced in any spatial direction relative to the drawer 342 and / or anode 343. In addition, or alternatively, it is possible to rotate it about these axial / spatial directions, for example, using a hexapod.

[0125] In addition, or alternatively, it is also possible to monitor the current intensity or current pattern in the region of the particle source 301. Then, based on the current pattern, it is possible to predict the remaining service life of the particle source 301 and, specifically, to initiate the replacement of the particle source 301. In principle, it is known that the emission characteristics of the particle source 301 change as the service life of the particle source 301 progresses, and how the emission characteristics typically change. An example of this is curve 352 in Figure 13B. In the current intensity curve 352 of an old particle source 301, there are no longer any teeth 354. There are also no longer any actual plateaus. Furthermore, there is also a change in the absolute current intensity, and the current intensity usually increases significantly again just before the particle source 301 fails. Based on this knowledge, it is also possible to predict the remaining service life of the particle source 301 and, specifically, to initiate the replacement of the particle source 301 in a timely manner.

[0126] Figure 14 schematically illustrates the acquisition of a current pattern at the anode aperture 343, which can be used to precisely tune the particle source 301. In addition, or alternatively, the acquisition of the current pattern can also be used to predict the service life of the current particle source 301 and / or to initiate the replacement of the working particle source 301. In principle, the current pattern can be acquired in various ways in the region of the particle source 301. As an example, the acquisition of the current pattern at the anode aperture 343 is described. However, of course, it is possible to perform the acquisition of the current pattern in a completely similar manner at the drawer aperture 342 or other separately provided apertures. Figure 14 simply illustrates the principle in this regard.

[0127] The anode aperture 343 has a central aperture 348 through which some of the emitted particles 309 pass. The passing particles are typically those that contribute to a plateau in current intensity 353 (see Figure 13B). Emitted particles also incident around the anode aperture 348 of the anode aperture 343. The current intensity or beam current density of these charged particles blocked by the aperture 343 can here be observed at spatial or local resolution. The anode aperture 343 shown in Figure 14A is used for this purpose, and various sectors S 11~S xy These sectors S are subdivided into these sectors S ij Separate beam current measurements can be performed in each of these. In the simplest case, a number of highly sensitive ammeters, such as picometers, are used for this purpose. In this case, individual sector S ij They are isolated from each other. Sector S ij This can take the form of a specially shaped sensor plate, and the insulation between sectors is implemented in a concealed manner by a complex, intricate structure so that the insulator is ultimately prevented from being charged by charged particles between sectors. Alternatively, individual sectors S ij It is possible to design it as a scintillator. Other embodiments for obtaining current patterns are also possible.

[0128] Figure 14B shows sector S for obtaining spatially resolved current patterns. ij This shows another geometric arrangement. In the example shown, this time we have individual sectors S i Three concentric rings, subdivided into smaller sections, are provided. Separate beam currents are directed to sector S i Measured for each sector. In Figure 14, for clarity, not all sectors are shown, nor are all current measuring devices shown.

[0129] In addition, or alternatively, it is also possible to monitor the beam current in a different manner to obtain a conclusion regarding the remaining service life of the working particle source 301 in this way. In this situation, please refer once again to the previously cited International Patent Application No. 2023 / 001402.

[0130] Figure 15 schematically shows a plan view of a metal cladding element 760 that can be inserted into the beam path of a multibeam particle microscope 1. The conductive cladding element 760 comprises a particle protection section 770 that functions as a cladding element in the narrow sense, and a region 770 that functions substantially as an extension of the beam tube. In the example shown, this tubular region 770 can be realized by a circular through-hole 762 in the cladding element 760. In the example shown, the cladding element 760 comprises a metal cantilever that is displaceable in the x-direction, and therefore displaceable in a direction perpendicular to the optical axis (the optical axis is in the plane of the diagram in Figure 15, i.e., in the z-direction). In Figure 15, this displaceability is indicated by a double arrow. The cladding element 760 can be precisely displaced in the x-direction because it is held and guided by element 765. The cladding element 760 may also be positioned above the multibeam generator 305 with respect to the particle light beam path of the multibeam particle microscope, so that, when inserted, the multibeam generator 305 is covered by the cladding element 760. The particle protection unit 770, when inserted, blocks or covers the beam tube. When not inserted, the beam tube is open, and charged particles pass through the through-holes of the covering element. The conductive covering element 760 can be embodied in various forms, in which case Figure 15 simply illustrates the functional principle. The covering element 760 can be designed, for example, as a metal slider or metal cantilever, or as a movable disk. This covering using the particle protection unit 770 further protects the multibeam generator 305 during particle source 301 replacement. During particle source 301 replacement, the conductive covering element not only protects from contamination at this time, but also protects the electronic components mounted on the multibeam generator 305 from scattered electrons and / or high-energy light radiation. Furthermore, it is possible to provide a multibeam particle microscope 1 that includes the described conductive covering element 760 but does not include the double sealing and tube separation module 710 according to the present invention.

[0131] Figure 16 schematically shows a cross-section of an exemplary configuration of the covering element 760. According to this exemplary embodiment, the covering element 760 comprises a metal cantilever 761 displaceable between a first fastening position 768 and a second fastening position 769 in the x-direction, or perpendicular to the particle beam path, or in this case, in the x-direction, or in the form of a metal cantilever 761. The two fasteners 768, 769 can be formed, for example, by a body 764 fixedly connected in space to the housings 708, 709 of the multibeam particle microscope 1. The cantilever 761 can be supported, for example, by a linear bush 765 and guided through the linear bush 765. The metal cantilever 761 has a through hole 762, and it is advantageous that the diameter of the through hole 762 matches the beam tube diameter of the beam tube adjacent to the through hole. Charged particles can pass through the through-hole 762 and through the covering element 760 without obstruction when the covering element is in the first locking position 768. The cantilever 761 further specifically has a circular recess 763, and it is advantageous that the diameter of the recess 763 also matches the beam tube diameter of the adjacent beam tube. Charged particles enter the recess when the cantilever 761 is in the second locking position during the operation of the multibeam particle microscope 1. If the housings 708, 709 are open and / or the vacuum inside the multibeam particle microscope 1 is broken, particles that would otherwise enter the area below the illumination tube 700 enter the recess. In this way, particles are additionally protected when the particle source 301 is replaced. Modifications of this embodiment have the further advantage that, in addition to the protective function, they can be used for the purpose of beam current measurement, and therefore for monitoring and / or adjustment purposes. This is because, according to a more preferred embodiment of the present invention, the beam current meter is specifically located in the circular recess 763 and / or the circular recess 763 is connected to the beam current meter. This makes it possible, for example, to measure scattered electrons. Alternatively, or in addition, the beam current can also be measured directly during the operation of the multi-beam particle microscope 1.

[0132] In a modified embodiment, the metal cantilever 760 has a predetermined thickness and extends laterally to or through the entire beam tube 703. This, in principle, enables an extension of the beam tube 703, allowing for better protection of the multi-beam generator 305, which includes electronic equipment and / or circuits located therein, from, for example, the generated X-ray radiation. The beam current meter can, in this modified embodiment as well, directly or indirectly monitor the beam current. In this modified embodiment as well, in principle, it is possible to record or monitor the beam current with spatial resolution. In this case, spatial resolution can be achieved in a manner similar to the principle described in Figures 13 and 14.

[0133] The exemplary embodiments described should not be construed as limiting the invention, but rather serve to better illustrate the invention. Furthermore, the exemplary embodiments described in the figures can be combined all or in part with each other, as long as no technical inconsistencies result.

[0134] (Explanation of symbols) 1. Multibeam particle microscope 3. Primary particle beam, first individual particle beam 5. Beam spot, entry point 7. Object, sample, wafer 9. Secondary particle beam, second individual particle beam 10. Computer systems, controllers 15. Sample surface, wafer surface 25 Image point of the second individual particle beam 101 Object surface 102 Objective lens 103 Field Lens 105 axis 200 Detector Systems 205 Projection Lens System 206 Projection Lens 207 Multi-particle detector 208 Projection Lens 209 Projection Lens 210 Projection Lens 212 Crossover 214 Aperture Filter, Contrast Aperture 220 Multi-aperture correctors, individual polarizer arrays 222 Batch Anti-Bias System 300 Beam Generator 301 Particle source 303 Collimation Lens System 305 multi-aperture array, multi-beam particle generator Microoptics with 306 multi-aperture plates 307 Field Lens 308 Field Lens 309 Particle beam 310 Outer beam cone 311 Collimated particle beam 321 Intermediate image plane 323 Beam Focus 340 Cathode Chips 342 Drawer, drawer drawer drawer 343 Anode, Anode aperture 344 Helmholtz coil pair 345 Helmholtz coil pair 346 aperture 347 Aperture 348 Aperture 350 optical axis 351 Current intensity of new particle source 352 Current intensity of old particle sources 353 Plateau 354 teeth 400 beam splitter, magnet array 500 Scanning Polarizer 503 Voltage source 600 Displacement stage or positioning device 700 Illumination Tube 701 Illumination tube head, replacement module 702 Remaining illumination tubes, remaining tubes 703 Beam Tube 704 First beam tube section 705 Second beam tube section 706 Sealing surface 707 Filling volume 708 cabinet 709 cabinet 710 Double Sealing and Tube Separation Module 711 First submodule 712 Second submodule 713 Intermediate components, adapters 714 First sealing element 715 Second sealing element 716 Intermediate area 717 Passageway, drilled hole 718 Vacuum airtight conduit 719 Vacuum pump 720 Storage 721 Vacuum-evacuated area within the storage facility 722 Shield elements 723 Shield element 724 Upper area 725 Lateral region 726 Sealing mechanism 727 Sealing mechanism 728 Conduit 729 Conduit 730 First Vacuum Region 731 Operating position 740 Second vacuum region 741 Storage Unit 742 Storage position 743 Conveyor Rod 744 Conveyor Rod 745 Ultra-high vacuum slider 746 Rotary conveyor 747 Center of rotation 748 Contact Unit 749 Electrical contacts 750 rod, connecting part 760 Covering element 761 Metal cantilever 762 Through hole 763 Circular recess 764 Main Unit 765 Holder, Guide 766 Diaphragm Bellows 767 abutment body 768 First fastener 769 Second fastener 770 Particle protection section 771 Beam tube extension V1 Volume V2 Volume V3 Volume V4 Volume T separation plane, separation area

Claims

1. A multibeam particle microscope equipped with a replaceable particle source, wherein the multibeam particle microscope is A particle source configured to emit charged particles, A multibeam generator configured to generate a first field of a large number of charged first individual particle beams from the charged particles, A first particle optical unit comprising a first particle light beam path, configured to image the generated first individual particle beam onto the sample surface of the object surface, thereby causing the first individual particle beam to incident on the sample surface at the incident site and form a second field. A detection system having multiple detection areas, forming a third field. A second particle optical unit comprising a second particle light beam path, configured to image a second individual particle beam emitted from the incident site of the second field onto the third field of the detection region of the detection system, A magnetic and / or electrostatic objective lens through which both the first individual particle beam and the second individual particle beam pass, A beam splitter is positioned between the multi-beam generator and the objective lens of the first particle light beam path, and between the objective lens and the detection system of the second particle light beam path. A sample stage for holding and / or positioning a sample during sample inspection. A controller configured to control the multibeam particle microscope, A beam tube having at least two beam tube portions positioned between the particle source and the beam splitter, wherein the beam tube is evacuated during the operation of the multibeam particle microscope, and the charged particles or the charged individual particle beam is guided into the beam tube during the operation of the multibeam particle microscope, and A double-sealed and tube-separating module is positioned in a sealed state between the two beam tube sections during the operation of the multibeam particle microscope, through which the charged particles or the first individual particle beam pass, and which is spatially separable into a first submodule and a second submodule when the multibeam particle microscope is not operating. It is equipped with, The first submodule includes a first sealing element configured to shield the beam tube portion adjacent to the particle source side in a sealed state when the first submodule and the second submodule are spatially separated, The second submodule includes a second sealing element configured to shield the beam tube portion adjacent to the beam splitter side in a sealed state when the first submodule and the second submodule are spatially separated, A multibeam particle microscope in which the double-sealed and barrel separation module has a passage in an intermediate region between the first sealing element and the second sealing element, so that the intermediate region can be evacuated to operate the multibeam particle microscope and the vacuum in the intermediate region can be broken to separate the first and second submodules.

2. A replacement module comprising the first sub-module of the double-sealing and barrel separation module, and also the components of the multi-beam particle microscope, including the particle source, positioned above the double-sealing and barrel separation module with respect to the particle light beam path. Furthermore, it is equipped with, The multibeam particle microscope according to claim 1, wherein the replacement module is configured to be replaced entirely within the multibeam particle microscope.

3. A focusing lens system is located downstream of the particle source and upstream of the multibeam generator in the particle light beam path, through which the charged particles pass. Furthermore, The multibeam particle microscope according to claim 1 or 2, wherein the double sealing and barrel separation module is located between the focusing lens system and the multibeam generator.

4. A focusing lens system is located downstream of the particle source and upstream of the multibeam generator in the particle light beam path, through which the charged particles pass. Furthermore, The aforementioned focusing lens system comprises a first, specifically a magnetic focusing lens, and a second, specifically a magnetic focusing lens. The multibeam particle microscope according to claim 1 or 2, wherein the double-sealing and barrel separation module is disposed between the first focusing lens and the second focusing lens.

5. A field lens system positioned downstream of the multi-beam generator and upstream of the beam splitter in the particle light beam path, through which the charged first individual particle beam passes. Furthermore, The field lens system comprises a first, specifically a magnetic field lens, and a second, specifically a magnetic field lens. The multibeam particle microscope according to claim 1, wherein the double sealing and barrel separation module is disposed between the first field lens and the second field lens.

6. The double sealing and lens barrel separation module is 10 -10 Configured to achieve an ultra-high vacuum of mbar, and / or The double sealing and lens barrel separation module is 10 -9 A multibeam particle microscope according to any one of claims 1 to 5, configured to achieve a leakage rate of less than or equal to mbar / l / second.

7. The double sealing and lens barrel separation module is conductive and has a relative permeability μ r but m r ≦1.005 A multibeam particle microscope according to any one of claims 1 to 6, comprising or composed of a material that satisfies the following conditions.

8. The multibeam particle microscope according to any one of claims 1 to 7, wherein the first sealing element and / or the second sealing element of the double sealing and barrel separation module comprises one element from the list of ultra-high vacuum sliders, flap valves, and pendulum valves.

9. The multibeam particle microscope according to any one of claims 1 to 8, wherein the first sealing element and / or the second sealing element are configured to be operated manually, pneumatically, or electrically.

10. With the module installed, the total height h of the double-sealed and barrel separation module, measured along the optical axis of the multibeam particle microscope, h ≤ 8.0 cm, specifically h ≤ 7.0 cm or h ≤ 6.0 cm A multibeam particle microscope according to any one of claims 1 to 9, satisfying the requirements of the claim.

11. The multibeam particle microscope according to any one of claims 1 to 10, wherein the double-sealed and barrel separation module further comprises a heating element disposed within the double-sealed and barrel separation module.

12. The multibeam particle microscope according to any one of claims 1 to 11, wherein the double-sealed and barrel separation module further comprises an adjustment member for adjusting the replacement module, the adjustment member being provided adjacent to the first partial module on the particle source side or incorporated into the first partial module on the particle source side.

13. The particle source comprises a cathode tip, an extractor throttling, and an anode throttling, which are arranged on the same plane as each other, or should be arranged on the same plane as each other. The drawer aperture comprises a drawer current meter configured to record a current pattern having spatial resolution around the aperture of the drawer, and / or The multibeam particle microscope according to any one of claims 1 to 12, wherein the anode aperture comprises an anode current meter configured to record a current pattern having spatial resolution around the anode aperture.

14. The multibeam particle microscope according to claim 13, wherein a cathode position adjustment means is provided for setting the position of the cathode relative to the drawer aperture and / or the anode aperture based on the recorded current pattern.

15. A conductive covering element, wherein the covering element is positioned above the multibeam generator with respect to the particle light beam path and is insertable into the particle light beam path such that the multibeam generator is covered by the covering element. A multibeam particle microscope according to any one of claims 1 to 14, further comprising:

16. The covering element is designed as a metal cantilever that is displaceable between a first fastener position and a second fastener position in a direction perpendicular to the particle light beam path, or comprises a metal cantilever. The metal cantilever has a through hole, the diameter of which matches the diameter of the beam tube adjacent to the through hole, and at the first fastener position, the charged particles can pass through the through hole and through the covering element without obstruction. The multibeam particle microscope according to claim 15, wherein the metal cantilever specifically has a circular recess, the diameter of which matches the diameter of the adjacent beam tubes, and the charged particles can be incident on the recess at the second fastener position.

17. The multibeam particle microscope according to claim 16, wherein a beam current meter is specifically located in the circular recess and / or the circular recess is connected to the beam current meter.

18. A multibeam particle microscope according to any one of claims 2 to 17, comprising an interchangeable module, At least one other interchangeable module for the multibeam particle microscope, A storage cabinet equipped with at least one vacuum-sealed connector for at least one other replacement module A system that is equipped with, A system in which the storage chamber is configured to store the inside of the other replacement module in the storage chamber under a high vacuum, specifically an ultra-high vacuum, when the first sealing element of the other replacement module is open.

19. A method for replacing the particle source of a multibeam particle microscope according to any one of claims 2 to 17, wherein the method is: The step of closing the first sealing element and the second sealing element of the double sealing and lens barrel separation module, The steps of breaking the vacuum in the region between the first sealing element and the second sealing element of the double sealing and lens barrel separation module, The steps include spatially separating the double-sealed and barrel separation module into the first and second sub-modules, thereby separating the first replacement module, which includes the first particle source, from the rest of the multibeam particle microscope; Steps include: placing a second replacement module, which includes a second particle source, on the remaining portion of the multibeam particle microscope, thereby assembling a second double seal and barrel separation module, wherein the second replacement module is pre-vacuumed and the first sealing element of the second replacement module is closed; The steps of vacuuming the area between the first sealing element and the second sealing element of the second double sealing and barrel separation module, After the vacuum evacuation is performed, the first sealing element of the second double seal and lens barrel separation module and the second sealing element of the second double seal and lens barrel separation module are opened. Methods that include...

20. Steps to heat the first double seal and barrel separation module and / or the second double seal and barrel separation module. The method according to claim 19, further comprising:

21. Steps to pre-adjust and / or technically pre-examine the second replacement module before it is placed on the rest of the multibeam particle microscope. The method according to claim 19 or 20, further comprising:

22. Steps include storing the second replacement module in a storage facility under vacuum. The method according to any one of claims 19 to 21, further comprising:

23. The steps of: positioning the second replacement module isotropically on the remaining portion of the multibeam particle microscope; The steps of adjusting the second replacement module using an adjustment member, and / or Steps to adjust the second replacement module using an electric and / or magnetic deflection field that deflects the charged particles and / or the charged first individual particle beam. The method according to any one of claims 19 to 22, further comprising:

24. The steps include monitoring the current pattern in the region of the particle source, A step of adjusting the components of the particle source relative to each other based on the current pattern. The method according to any one of claims 19 to 23, further comprising:

25. The steps include: monitoring the current pattern in the region of the particle source; In each case, the remaining service life of the particle source is predicted based on the current pattern, and specifically, the step of initiating the replacement of the particle source is... The method according to any one of claims 19 to 24, further comprising:

26. The method according to any one of claims 19 to 25, wherein the method is performed in whole or in part multiple times, specifically, a third replacement module having a third particle source, or another replacement module having another particle source, is positioned on the remaining portion of the multibeam particle microscope.

27. A multibeam particle microscope equipped with a replaceable particle source, wherein the multibeam particle microscope is A first vacuum region comprising a first particle source configured to emit charged particles, A multibeam generator configured to generate a first field of a large number of charged first individual particle beams from the charged particles, A first particle optical unit comprising a first particle light beam path, configured to image the generated first individual particle beam onto the sample surface of the object surface, thereby causing the first individual particle beam to incident on the sample surface at the incident site and form a second field. A detection system having multiple detection areas, forming a third field. A second particle optical unit comprising a second particle light beam path, configured to image a second individual particle beam emitted from the incident site of the second field onto the third field of the detection region of the detection system, A magnetic and / or electrostatic objective lens through which both the first individual particle beam and the second individual particle beam pass, A beam splitter is positioned between the multi-beam generator and the objective lens of the first particle light beam path, and between the objective lens and the detection system of the second particle light beam path. A sample stage for holding and / or positioning a sample during sample inspection. A controller configured to control the multibeam particle microscope, A second vacuum region comprising a storage unit having at least one second particle source having the same structure as the first particle source as a replacement particle source, and A transport mechanism for vacuum transporting the second particle source from the storage unit in the second vacuum region to an operable position in the first vacuum region. A multi-beam particle microscope equipped with the following features.

28. The multibeam particle microscope according to claim 27, wherein the transport mechanism is further configured to vacuum transport the first particle source from the operable position in the first vacuum region to the storage unit in the second vacuum region.

29. The first vacuum region and the second vacuum region are formed as separate vacuum chambers, or The multibeam particle microscope according to claim 27 or 28, wherein the first vacuum region and the second vacuum region are located within the same vacuum chamber.

30. The multibeam particle microscope according to any one of claims 27 to 29, wherein the storage unit has a plurality of storage positions arranged according to a physically linear topology for the replacement particle source.

31. The multibeam particle microscope according to any one of claims 27 to 29, wherein the storage unit has a plurality of storage positions for the replacement particle source arranged according to a physically star-shaped topology.

32. The multibeam particle microscope according to any one of claims 27 to 29, wherein the storage unit has a plurality of storage positions arranged according to a physically ring-shaped topology for the replacement particle source.

33. In the aforementioned operable position, a contact unit that electrically contacts each of the operating particle sources, An adjustment unit and A multibeam particle microscope according to any one of claims 27 to 32, further comprising:

34. A multibeam particle microscope according to any one of claims 27 to 33, comprising a tip cathode, an extractor electrode, and an anode, each of which is pre-adjusted relative to one another and / or technically pre-tested.

35. A multibeam particle microscope equipped with a replaceable particle source, wherein the multibeam particle microscope is Multiple identically constructed particle sources, fixedly positioned in space and configured to emit charged particles, A switching means configured to switch between the aforementioned multiple particle sources, thereby ensuring that at any given time, exactly one of the particle sources becomes the active particle source that emits charged particles. Electrical and / or magnetic deflection means configured to deflect the charged particles emitted from each of the aforementioned operating particle sources onto the optical axis of the multibeam particle microscope, A multibeam generator configured to generate a first field of a number of charged first individual particle beams from the charged particles from a particle source, A first particle optical unit comprising a first particle light beam path, configured to image the generated first individual particle beam onto the sample surface of the object surface, thereby causing the first individual particle beam to incident on the sample surface at the incident site and form a second field. A detection system having multiple detection areas, forming a third field. A second particle optical unit comprising a second particle light beam path, configured to image a second individual particle beam emitted from the incident site of the second field onto the third field of the detection region of the detection system, A magnetic and / or electrostatic objective lens through which both the first individual particle beam and the second individual particle beam pass, A beam splitter is positioned between the multi-beam generator and the objective lens of the first particle light beam path, and between the objective lens and the detection system of the second particle light beam path. A sample stage for holding and / or positioning a sample during sample inspection. A controller configured to control the particle source, the switching means, and the deflection means. A multi-beam particle microscope equipped with the following features.

36. The multibeam particle microscope is equipped with exactly four particle sources, the four particle sources are arranged in pairs facing each other, and each of the particle sources is positioned to emit charged particles perpendicular to the optical axis of the multibeam particle microscope. The deflection means comprises two pairs of Helmholtz coils, i.e., four coils in total, and in each case, only one pair of Helmholtz coils is operating at any given time. Each coil is positioned between one of the particle sources and the virtual extension of the optical axis of the multibeam particle microscope. The axes of the Helmholtz coil pair are positioned so as to be perpendicular to the optical axis of the multibeam particle microscope, thereby directing the magnetic fields that can be generated by each Helmholtz coil pair so as to be perpendicular to the optical axis of the multibeam particle microscope. The multibeam particle microscope according to claim 35, wherein the controller is configured to control the pair of Helmholtz coils such that the charged particles emitted from each of the operating particle sources are deflected in the direction of the optical axis of the multibeam particle microscope.

37. The multibeam particle microscope is equipped with exactly four particle sources, and the four particle sources are arranged in pairs facing each other, and each is tilted at an angle α ≠ 0° with respect to the optical axis of the multibeam particle microscope, specifically by 40° ≤ α ≤ 50°. The deflection means comprises four deflection electrodes, each assigned to a particle source, specifically the four anodes of the four particle sources. The multibeam particle microscope according to claim 35, wherein the controller is configured to use a deflection potential to control the deflection electrodes of the particle sources, each facing the working particle source, such that the charged particles emitted from each of the working particle sources are deflected in the direction of the optical axis of the multibeam particle microscope.

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