Multi-beam particle microscope with rapidly replaceable particle source and method for rapidly replacing particle source in multi-beam particle microscope

Abstract

A multi-beam particle microscope with a rapidly replaceable particle source is disclosed. To this end, the multi-beam particle microscope comprises specific dual-sealing and column separation modules. By means of the dual-seal and column separation module, a replacement module with a particle source can be replaced more quickly, and potentially sensitive component parts of a particle optical assembly of the multi-beam particle microscope can be protected from contamination.

Description

TECHNICAL FIELD

[0001] The present invention relates to a multi-beam particle microscope operated with a plurality of charged individual particle beams. In particular, the present invention relates to a multi-beam particle microscope having a particle source or cathode which can be quickly replaced. BACKGROUND

[0002] As microstructures such as semiconductor components are continuously developed which are smaller and more complex, there is a need for further development and optimization of planarization techniques, as well as inspection systems for the generation and inspection of small-sized microstructures. For example, the development and generation of semiconductor components requires monitoring the design of test wafers, while planarization techniques require process optimization for reliable generation with high yield. Furthermore, there is a recent need for analyzing the construction of semiconductor wafers and customer-specific, individual semiconductor components for reverse engineering. Therefore, there is a need for inspection means which can be used with high yield, to inspect microstructures on wafers with high precision.

[0003] Typical silicon wafers for generating semiconductor components have a diameter of up to 300 mm, each wafer being subdivided into 30 to 60 repeating areas ("dies") of up to 800 mm 2 A semiconductor device comprises a plurality of semiconductor structures generated in layers on the surface of a wafer by planar integration techniques. Due to the generation process, semiconductor wafers usually have a planar surface. The structure size of the integrated semiconductor structures in this case extends from a few µm to critical dimensions (CD) of a few nm, and in the near future the structure size will become even smaller; future structure sizes or critical dimensions (CD) are expected to correspond to process nodes of 3 nm, 2 nm or even smaller according to the International Technology Roadmap for Semiconductors (ITRS). At the aforementioned smaller structure sizes, defects of the size of the critical dimension must be identified quickly over very large areas. For several applications, the specification requirements regarding the measurement accuracy provided by the inspection apparatus are even higher, for example two times or one order of magnitude. For example, the width of a semiconductor feature must be measured with an accuracy of less than 1 nm, for example 0.3 nm or even less, and the relative positioning of semiconductor structures must be determined with an overlay accuracy of less than 1 nm, for example 0.3 nm or even less.

[0004] Multi-beam scanning electron microscopes (MSEM) are 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 US 7 244 949 B2 and US 2019 / 0355544 A1. In the case of multi-beam electron microscopes or MSEM, a sample is simultaneously irradiated by a plurality of individual electron beams, which are arranged in a field or raster. For example, 4 to 10 000 individual electron beams can be provided as a primary radiation, each individual electron beam being separated from an adjacent individual electron beam by a spacing of 1 to 200 micrometers. For example, an MSEM has approximately 100 individual electron beams ("small beams"), which are arranged, for example, in a hexagonal raster, wherein the individual electron beams are separated by a spacing of approximately 10 pm. The plurality of charged individual particle beams (primary beams) is focused by a common objective onto the surface of a sample to be inspected. The sample can be, for example, a semiconductor wafer fixed to a wafer carrier mounted on a movable stage. When the wafer surface is irradiated with the charged primary individual particle beams, interaction products, such as secondary electrons or backscattered electrons, are emitted from the wafer surface. Their point of origin corresponds to those locations on the sample at which, in each case, a plurality of primary individual particle beams is focused. The number and energy of the interaction products depend on the material composition and the layout of the wafer surface. The interaction products form a plurality of secondary individual particle beams (secondary beams), which are collected by a common objective and, by means of a projection imaging system of the multi-beam inspection system, are incident on a detector arranged in a detection plane. The detector comprises a plurality of detection regions, each region comprising a plurality of detection pixels, and the detector acquires an intensity distribution of each of the secondary individual particle beams. An image field of, for example, 100 pm x 100 pm is obtained in the process.

[0005] Prior art multi-beam electron microscopes comprise a series of electrostatic and magnetic elements. At least some of the electrostatic and magnetic elements can be set to adapt the focus position and stigmation of the plurality of charged individual particle beams. Prior art multi-beam systems with charged particles further comprise at least one cross-plane of primary or secondary individual charged particle beams. Furthermore, prior art systems comprise a detection system to aid adjustment. Prior art multi-beam particle microscopes comprise at least one beam deflector ("deflection scanner") for collectively scanning a region of the sample surface by the plurality of primary individual particle beams to obtain an image field of the sample surface.

[0006] With increasing requirements for imaging quality, requirements for multi-beam particle microscopes for imaging also increase. Stable operating parameters are very important for high-quality recordings. One of them is the beam current intensity of the individual particle beams used to scan the sample surface.

[0007] For a homogeneous beam intensity of the individual particle beams, the emission properties of the particle source are important, more precisely the homogeneity of the emission properties over the entire used emission angle. When using a relatively large emission angle, the emission properties of a particle source, for example a thermal field emission (TFE) source, are no longer completely homogeneous. As a result, the irradiance at the first multi-aperture plate in the respective particle beam system is also no longer completely homogeneous, and there is a relatively large variation in the current density in the different individual beams. In the case of a multi-particle inspection system, however, the system requires only a small variation in the current intensity between the individual beams, usually less than a few percent, and even less than one percent, so that all individual image fields of the multi-image field are scanned with an equal number of particles or electrons. This is, for example, a prerequisite for obtaining individual images with approximately the same brightness. The achievable resolution of the individual images also depends on the individual beam current. There are options for setting the beam current of the individual particle beams. One option in this regard is disclosed in DE 10 2018 007 652 A1, the disclosure of which is incorporated by reference in its entirety into the present patent application.

[0008] When the particle source or the tip ages, further problems arise with the particle source; for example, it can lose brightness. The brightness of an image, in turn, is related to the brightness or illuminance of the light source. If the light source loses brightness, this also applies to the image brightness. This can be at least temporarily compensated for by increasing the gain of the detection system, although this can result in a worsening of the signal-to-noise ratio (SNR) of the detector and a reduction in the contrast that can be achieved in the image. A further at least temporary solution consists in changing the voltage applied to the extraction electrode or in providing an additional electrostatic control lens between the extraction electrode and the anode, as proposed in WO 2023 / 001402 A1, the disclosure of which is incorporated by reference in its entirety into the present patent application. Furthermore, it is proposed to estimate the remaining useful life of the particle source or the cathode tip and to selectively activate a particle source change. Furthermore, WO 2023 / 001401 A1 discloses a multi-beam particle microscope that enables a high-precision beam current control. The disclosure of WO 2023 / 001401 A1 is likewise incorporated by reference in its entirety into the present patent application.

[0009] However, the useful life of the particle source or the cathode tip inevitably reaches an end at some point, and the particle source has to be replaced. According to the prior art, such a replacement takes several hours or even days, thus resulting in a standstill time or downtime of the multi-beam particle microscope, and this leads to a relatively long system downtime, which is disadvantageous, in particular when the multi-beam particle microscope is integrated into a production line.

[0010] In order to replace a particle source in a multi-beam particle microscope, the region in which the particle source or the cathode tip is located must first be made accessible. For example, a housing located in the upper region must be removed. The vacuum or high vacuum in the multi-beam particle microscope must be destroyed; only then can a technician replace the particle source or the cathode tip. Subsequently, the multi-beam particle microscope must be reassembled; the region for evacuation must then be evacuated and baked again. Subsequently, the multi-beam particle microscope with the new or replaced particle source must be readjusted. The replacement of the particle source usually takes about 30 hours, but can also take longer.

[0011] In addition to the unnecessary time expenditure, the replacement of the particle source also entails a further problem: the particle-optical components used in the multi-beam particle microscope can be exposed to contamination as a result of the vacuum destruction. So-called micro-optical components, which are constituent parts of the multi-beam generator, are particularly sensitive in this respect. Here, contamination has a particularly large influence on the beam quality of the individual particle beams generated, and should be avoided as far as possible. SUMMARY

[0012] It is therefore an object of the present patent application to provide a multi-beam particle microscope and a related method in which the particle source can be replaced more quickly. In this case, the replacement of the particle source should be as simple as possible and be carried out in the best possible time.

[0013] A further object is to also avoid, if possible, contamination of the multi-beam generator or the micro-optical components when the particle source is replaced.

[0014] The one or more objects can be achieved by the subject matter of the independent claims. Advantageous embodiments of the present application will be apparent from the dependent patent claims.

[0015] The present patent application claims priority from German patent application No. 10 2023 107 961.1 filed on March 29, 2023, the disclosure of which is incorporated by reference in its entirety into the present application.

[0016] The core concept of the present application is to reduce the time taken for the replacement of the particle source by significantly reducing the time required for the evacuation of the multi-beam particle microscope.

[0017] According to one aspect of the present application, this is achieved by significantly reducing the volume of the vacuum that needs to be evacuated for the particle source exchange and is successful in this matter due to the clever configuration of the dual sealing and column separation module. The interior of the dual sealing and column separation module is the only volume that needs to be evacuated during the exchange itself compared to the entire system. Furthermore, by implementing a module-based particle source exchange, the source or its constituent parts can be pre-qualified and / or pre-adjusted with respect to each other, which saves valuable time during the actual particle source exchange. Moreover, in some embodiment variants, the dual sealing and column separation module can protect sensitive constituent parts of the multi-beam particle microscope, such as micro-optical components, from contamination.

[0018] According to another aspect of the present application, the time spent for exchanging the particle source is minimized by completely avoiding the destruction of the vacuum, re-evacuation and baking. This is successfully solved, for example, by having a storage solution for multiple particle sources or replacing the particle source completely in vacuum, or by using electrostatic and / or magnetic deflection means to switch between multiple particle sources. Contamination can also be avoided in these solutions.

[0019] Aspects of the present application are explained in more detail below:

[0020] According to a first aspect of the present application, it relates to a multi-beam particle microscope with an exchangeable particle source, having the following features:

[0021] a particle source configured to emit charged particles;

[0022] a multi-beam generator configured to generate a first field of a plurality of charged first individual particle beams from the charged particles;

[0023] a first particle optical unit having a first particle beam path configured to image the generated first individual particle beams onto a sample surface in the object plane such that the first particle beams are incident on the sample surface at an incidence position, the incidence position forming a second field;

[0024] a detection system having a plurality of detection areas forming a third field;

[0025] a second particle optical unit having a second particle beam path configured to image second individual particle beams emanating from the incidence position in the second field onto the third field of the detection areas of the detection system;

[0026] a magnetic and / or electrostatic objective lens, both the first and the second individual particle beams passing through the objective lens;

[0027] a beam splitter configured in the first particle beam path between the multi-beam generator and the objective, and configured in the second particle beam path between the objective and the detection system;

[0028] a sample stage for holding and / or positioning a sample during sample inspection;

[0029] a controller configured to control the multi-beam particle microscope;

[0030] a beam tube having at least two beam tube sections configured between the particle source and the beam splitter, wherein the beam tube is evacuated during operation of the multi-beam particle microscope, and wherein said charged particles or said charged first individual particle beams are guided within the beam tube during operation of the multi-beam particle microscope; and

[0031] a double-sealing and column separation module sealing configured between said two beam tube sections during operation of the multi-beam particle microscope, and said charged particles or said first individual particle beams pass through the double-sealing and column separation module, and the double-sealing and column separation module is spatially separated into a first partial module and into a second partial module when the multi-beam particle microscope is not in operation,

[0032] wherein the first partial module comprises a first sealing element configured to seal off the particle source-side adjacent beam tube section in case of spatial separation between the first and second partial modules,

[0033] wherein the second partial module comprises a second sealing element configured to seal off the beam splitter-side adjacent beam tube section in case of spatial separation between the first and second partial modules, and

[0034] wherein the double-sealing and column separation module comprises an access within an intermediate region between the first sealing element and the second sealing element, such that the intermediate region can be evacuated for operation of the multi-beam particle microscope, and the vacuum in the intermediate region can be broken for the purpose of separating the first partial module and the second partial module.

[0035] At least one particle source is provided, but also a plurality of particle sources can be provided. The charged particles can be, for example, electrons, positrons, mesons or ions or other charged particles. Preferably, the charged particles are electrons generated, for example, using 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 rastered, for example, line by line or column by column. In this case, it is preferred that the individual field regions adjoin one another or cover the object or a portion thereof in a mosaic fashion. The individual field regions are substantially separated from one another, but they can also overlap one another in edge regions. In this way, a complete and continuous image of the object can be obtained. Preferably, the individual field regions have a rectangular or square shape, since this is the easiest to implement for a scanning process using particle radiation. Preferably, the individual field regions are configured as rectangles in different rows, one above the other, to generally form a hexagonal structure. It is advantageous if, in the hexagonal case, the number of particle beams is 3n(n-1) + 1, where n is an arbitrary natural number. Other configurations of the individual field regions are likewise possible, for example, square or rectangular raster.

[0036] The second individual particle beam can be a backscattered electron or a secondary electron. In this case, low-energy secondary electrons are preferably used for generating an image for analysis purposes. However, mirror ions / mirror electrons can also be used as a second individual particle beam, that is to say, a first individual particle beam which is directly inverted upstream of the object or at the object.

[0037] The beam tube describes the region of the multi-beam particle microscope in which a vacuum is drawn when the multi-beam particle microscope is in operation. In the present case, the beam tube itself can have a single-part or multi-part design. It can comprise a tubular portion and / or a cavity-like portion. The charged particles or the charged individual particle beams are guided in the beam tube during operation of the multi-beam particle microscope. For example, the beam tube itself can consist of steel or stainless steel or at least partially of titanium. The two beam tube portions according to claim 1 are spaced apart from one another and are substantially separated from one another by the double-sealing and column separation module. In this case, the double-sealing and column separation module is arranged in a sealing configuration between the two beam tube portions during operation of the multi-beam particle microscope. The double-sealing and column separation module is thus designed in such a way that the vacuum prevailing in the beam tube or in the two beam tube portions can be maintained therein during operation of the multi-beam particle microscope. When the multi-beam particle microscope is not in operation, the double-sealing and column separation module can be spatially divided into a first partial module and a second partial module. This separability is also expressed by the term "column separation module". Furthermore, each of the first partial module and the second partial module can have a single-part or multi-part design. An intermediate piece, for example an adapter, can be provided between the first partial module and the second partial module.

[0038] The term "dual sealing module" has been introduced to mean that at least two sealing elements are provided in the dual sealing and column separation module: in the present context, the first part module comprises a first sealing element and the second part module comprises a second sealing element. The first sealing element is configured to seal off the particle source side adjacent beam tube section in case of a spatial separation of the first part module and the second part module of the dual sealing and column separation module. In this case, the sealing off can be direct or indirect. In this case, the sealing element can have a size corresponding to the diameter of the adjacent beam tube section; however, it need not reach the entire width of the first part module. Similarly, the second sealing element is configured to seal off the beam splitter side adjacent beam tube section in case of a spatial separation of the first part module and the second part module of the dual sealing and column separation module. Thus, before dismounting or separating the dual sealing and column separation module into the first part module and the second part module, a vacuum tight sealing off can be obtained in each case by actuating the first sealing element and the second sealing element, which sealing off serves the elements or regions of the beam tube above and below the dual sealing and column separation module. Thus, it is not necessary to destroy the vacuum in these regions and to re-evacuate them at a later stage after replacement of the particle source.

[0039] In contrast, the vacuum is only destroyed or re-established at a later stage of the dual sealing and column separation module: for this purpose, the dual sealing and column separation module comprises an inlet in an intermediate region between the first sealing element and the second sealing element, so that the intermediate region can be evacuated for the operation of the multi-beam particle microscope and the vacuum in the intermediate region can be destroyed for the purpose of separating the first module and the second module. This inlet can be a single-part or multi-part inlet. In the case of a simple exemplary embodiment, the inlet is a drilled hole, a line is connected to the drilled hole, for example in a vacuum-tight manner, and the line is in turn connected or connectable to a vacuum pump.

[0040] According to a preferred embodiment of the present application, the multi-beam particle microscope further comprises the following:

[0041] A replacement module comprising the first part module of the dual-sealing and column separation module and constituent components of the multi-beam particle microscope which are arranged above the dual-sealing and column separation module with respect to the particle beam path, including the particle source. In this case, the replacement module is configured to be replaced as a whole in the multi-beam particle microscope. The replacement module can thus comprise not only the particle source itself, but also further elements of the multi-beam particle microscope as necessary constituent components. In principle, this depends on the position of the dual-sealing and column separation module in the illumination column or in the particle beam path of the multi-beam particle microscope. In this case, the particle source to be replaced can be one component or a plurality of components. For example, it can comprise a cathode, an extraction electrode and an anode. Furthermore, it can also comprise a suppression electrode. The arrangement of these elements within the particle source can already be pre-characterized and / or pre-adjusted in the (new) replacement module. Overall, this facilitates the adjustment of the (new) replacement module with respect to the remaining illumination column of the multi-beam particle microscope. Preferably, the replacement module comprises all constituent components of the multi-beam particle microscope which are arranged above the dual-sealing and column separation module with respect to the particle beam path. In other words, the replacement module in this case comprises the entire "head" of the illumination column.

[0042] According to a preferred embodiment of the present application, the multi-beam particle microscope further comprises the following:

[0043] A condenser lens system which is arranged in the particle beam path downstream of the particle source and upstream of the multi-beam generator and through which the charged particles pass, wherein the dual-sealing and column separation module is arranged between the condenser lens system and the multi-beam generator. In this case, the condenser lens system can comprise one or a plurality of condenser lenses. If the dual-sealing and column separation module is arranged between the condenser lens system and the multi-beam generator, it is configured in this way so that in this embodiment variant the charged particles initially pass through all condenser lenses of the condenser lens system before reaching the multi-beam generator. The condenser lens system is thus a constituent component of the replacement module in this embodiment of the present application. This embodiment likewise configures the dual-sealing and column separation module above the multi-beam generator. It is thus also not replaced in this process. Rather, when the replacement module containing the particle source is replaced, the beam tube section which in this embodiment variant is located upstream of the multi-beam generator in the direction of the particle beam path and adjacent to the beam splitter side is sealed off. As a result of this sealing, the multi-beam generator, in particular the micro-optical components arranged therein, is protected from contamination during the particle source replacement.

[0044] According to a further preferred embodiment of the present application, the multi-beam particle microscope comprises the following:

[0045] A condenser lens system is configured in the particle beam path downstream of the particle source and upstream of the multi-beam generator, and the charged particles pass through the condenser lens system, wherein the condenser lens system comprises a first special magnetic condenser lens and a second special magnetic condenser lens, and wherein the double-sealing and column separation module is configured between the first condenser lens and the second condenser lens. For example, the double-sealing and column separation module can be configured within a drift path of the condenser lens system. Overall, this saves installation space or column height. In this embodiment of the invention, the replacement module comprises only a part of the condenser lens system, in particular at least one special magnetic condenser lens. Thus, the replacement module is smaller or comprises fewer constituent components, and this requires fewer resources. However, the double-sealing and column separation module is located in the particle beam path above the multi-beam generator, so that the multi-beam generator can be protected by the second sealing element of the second part module of the double-sealing and column separation module when the particle source is replaced.

[0046] It is theoretically also conceivable to provide the double-sealing and column separation module between the particle source and the condenser lens system. However, this is likely to be avoided in practice, since the particle source and the condenser lens system are very close together, and there is usually too little space left for the configuration of the double-sealing and column separation module.

[0047] According to a further preferred embodiment of the invention, the multi-beam particle microscope further comprises the following:

[0048] A field lens system is configured in the particle beam path downstream of the multi-beam generator and upstream of the beam splitter, and the charged first individual particle beams pass through the field lens system, wherein the field lens system comprises a first special magnetic field lens and a second special magnetic field lens, and wherein the double-sealing and column separation module is configured between the first field lens and the second field lens. However, the field lens system can also essentially comprise more than two field lenses. In this case, the first field lens is considered to be the field lens that is closest to the multi-beam generator. Thus, in this embodiment of the invention, the illumination column is separated directly below the multi-beam generator or after the first field lens. Thus, the replacement module itself is relatively large or complex. However, this offers the advantage that the entire relatively large replacement module, which contains the particle source and the multi-beam generator, and optionally the condenser lens system located therebetween, can be pre-characterized and / or pre-adjusted before the particle source has to be replaced. Thus, the replacement of the particle source in the range of the replacement module can take place more quickly. In addition, contamination or soiling of the multi-beam generator as a whole is prevented.

[0049] According to a preferred embodiment of the invention, the double-sealing and column separation module is configured to achieve an ultra-high vacuum of 10 -10 millibar or more; and / or the double-sealing and column separation module is configured to achieve an ultra-high vacuum of less than or equal to 10-9 mbar / l / s. Thus, when separating the first part module and the second part module, a correspondingly high vacuum can be maintained in the (old or new) replacement module and the remaining lighting column. Moreover, this makes the double-sealing and column separation module usable without problems during operation of the multi-beam particle microscope; the ultra-high vacuum required by the multi-beam particle microscope is not impaired, and the leakage rate does not become too high.

[0050] According to a preferred embodiment of the application, the double-sealing and column separation module comprises or consists of an electrically conductive material, and has a relative magnetic permeability μ r for which the following applies: μ r ≤ 1.005. This relative magnetic permeability can be obtained by some stainless steel alloys and some titanium materials. Details about the relative magnetic permeability of materials used to manufacture the beam tube part are also disclosed in German patent application No. 10 2022 124 933.6, the disclosure of which is incorporated by reference in its entirety into the present patent application. The materials specified therein can also be used as materials for the double-sealing and column separation module.

[0051] According to a preferred embodiment of the application, the first and / or second sealing element of the double-sealing and column separation module comprises an element from the list: ultra-high vacuum slide, flap valve, pendulum valve. However, the first sealing element and / or the second sealing element can also have a different design.

[0052] According to a preferred embodiment of the application, the first sealing element and / or the second sealing element is configured to be operated manually, pneumatically or electrically. In this context, in particular in the case of non-manual operation, the first sealing element and / or the second sealing element can be controlled by a signal from a controller of the multi-beam particle microscope. However, the non-manual control can also be implemented independently of the controller of the multi-beam particle microscope.

[0053] According to a preferred embodiment of the present application, the following relation applies to the total height h of the double sealing and column separation module measured along the optical axis of the multi-beam particle microscope in the installed state: h < 8.0 cm, preferably h < 7.0 cm, most preferably h < 6.0 cm. In this case, the double sealing and column separation module has a minimum height h due to the design, for example approximately 5.0 cm, to ensure the necessary stability and sealing of the double sealing and column separation module. At the same time, however, it is necessary to keep the height h as low as possible in order not to unnecessarily increase the total height of the illumination column, which is important in any case. In this context, the ceiling height of the laboratory is often a limiting factor. Furthermore, the specified total height h of the double sealing and column separation module is sufficiently low here to accommodate the double sealing and column separation module within a drift path, for example in the illumination column. Such a drift path can be provided, for example, within the condenser lens system.

[0054] According to a further preferred embodiment of the present application, the double sealing and column separation module further comprises a heating element arranged within the double sealing and column separation module. This heating element can accelerate or even make it possible to generate a high vacuum within the double sealing and column separation module. Local heating can increase the desorption rate of the chamber walls, as a result of which an ultrahigh vacuum can be achieved more quickly. It is possible for the heating element to be controlled by means of a controller of the multi-beam particle microscope in the installed state of the multi-beam particle microscope or during operation of the multi-beam particle microscope. In this context, the heating element itself can be designed in various ways. For example, it can be designed as a flat heating plate or a flat mat; in this case, it can be inserted, for example, flat into the intermediate space between the first part module and the second part module. However, the heating element can also have a substantially cylindrical shape and / or be wound or hung around one part module or both part modules. The heating element can be made of several parts and / or several heating elements are provided, and, for example, a first heating element is arranged in the first part module and a second heating element is arranged in the second part module of the double sealing and column separation module.

[0055] According to a further preferred embodiment of the present application, the double sealing and column separation module further comprises an adjustment for adjusting the replacement module, wherein the adjustment is arranged adjacent to or integrated in the first part module on the particle source side. The adjustment facilitates a high-precision adjustment of the (new) replacement module on the remaining illumination column of the multi-beam particle microscope. For example, the adjustment can comprise bellows, allowing lateral, axial and / or tilting movements during fine adjustment of the replacement module on the remaining illumination column. In this case, the adjustment can be flange-mounted to the first part module, for example. However, it is also conceivable for the adjustment and the bellows to be designed integrally with the first part module.

[0056] According to a further preferred embodiment of the present application, the particle source of the multi-beam particle microscope comprises a cathode tip, an extraction aperture and an anode aperture, which are arranged flush with each other or should be arranged flush with each other. Additionally, the particle source can comprise a suppression electrode, which surrounds the cathode tip, for example like a cylindrical side surface, and serves for suppressing a lateral emission of electrons from the cathode tip. For example, the cathode tip can be a thermal field emitter; however, other configurations are possible in principle. For the flush arrangement of the cathode tip, the extraction aperture and the anode aperture, the center of the cathode tip, the center of the extraction aperture and the center of the anode aperture are exactly on one line or on the optical axis. This precise positioning is particularly important for high-precision recordings by means of the multi-beam particle microscope and this ensures that the particle source or the particles provided thereby are used optimally. Spatially, the cathode tip emits a particle cone, wherein the beam current through the cross section of the cone has an approximately plateau-shaped profile in a wide range, which then changes towards the edge of the cone and usually increases in this direction (forming a "tooth-like" shape), and then drops significantly at the outside. The outer regions of the particle cone beam can now be cut by means of the extraction aperture and / or the anode aperture. In other words, the charged particles usually impinge at least on a portion of the extraction aperture and / or the anode aperture. This fact can be used for monitoring the cathode tip and / or for adjusting the constituent parts of the particle source. Thus, in this embodiment of the present application, the extraction aperture comprises an extraction current meter configured to record the current pattern around the extraction aperture with spatial resolution and / or the anode aperture comprises an anode current meter configured to record the current pattern around the anode aperture with spatial resolution. In this context, spatial resolution is to be understood to mean that it is not only the overall current that is established. Rather, the position dependence of the beam current can also be reproduced in the current pattern. In this case, this relates to at least two, but preferably more than two, positions or sectors. The extraction current meter and / or the anode current meter may, for example, comprise sensor plates insulated from each other as current measurement probes, which are arranged around the corresponding aperture and are grounded, wherein a current measurement device is connected between the plates and the ground. Alternatively, a scintillator on the aperture can be used as a current meter and a brightness distribution on the scintillator plate can be established. Thus, in this case, the beam current is determined indirectly. Other embodiment variants are possible in principle.

[0057] According to a further preferred embodiment of the present application, a cathode positioning adjustment means is provided to set the position of the cathode relative to the extraction aperture and / or relative to the anode aperture based on the recorded current pattern. For example, the cathode tip can be moved, rotated and / or tilted in all three spatial directions. For this purpose, the cathode tip can be mounted, for example, by means of a six-legged stand. However, other fine adjustment means or mounts are possible.

[0058] According to a further preferred embodiment of the present application, the multi-beam particle microscope further comprises the following:

[0059] A conductive cover element, which is arranged above the multi-beam generator with respect to the particle beam path and which can be inserted into the particle beam path, such that in the inserted state the multi-beam generator is covered by the cover element. For example, the conductive cover element can be designed as a metal slide or as a metal cantilever, or as a movable disk. The cover can also protect the multi-beam generator during replacement of the particle source. During replacement of the particle source, the conductive cover element serves not only to prevent contamination, but also to protect electronic components installed in the multi-beam generator from scattered electrons and / or high-energy optical radiation.

[0060] Furthermore, a multi-beam particle microscope can be provided which has the conductive cover element, but not the double seal and the column separation module according to the invention.

[0061] According to a further preferred embodiment of the invention, the cover element is designed as a metal cantilever, which can be displaced between a first diaphragm position and a second diaphragm position orthogonal to the particle beam path,

[0062] wherein the metal cantilever has a through-hole, the diameter of which matches the beam tube diameter of a beam tube adjacent to the through-hole, and in the first diaphragm position the charged particles can pass unhindered through the cover element through the through-hole, and

[0063] wherein the metal cantilever has a recess, in particular circular, the diameter of which matches the beam tube diameter of an adjacent beam tube, wherein charged particles are incident into the recess at the second diaphragm position. Thus, for example, the metal cantilever is a slide which can be moved back and forth between the two diaphragm positions, and which in one case introduces a through-hole into the particle beam path and in the other case a recess, in particular circular. In addition to the protection function, this variant has the further advantage that it can be used for beam current measurement purposes, for monitoring purposes and / or for adjustment purposes: This is because, according to a further preferred embodiment of the invention, a beam current meter is arranged in the recess, in particular circular, and / or the circular recess is connected to a beam current meter. This makes it possible, for example, to measure scattered electrons. Alternatively or additionally, the direct beam current can also be measured.

[0064] According to an embodiment variant, the metal cantilever has a certain thickness and extends transversely to or through the entire beam tube. In principle, this achieves a beam tube lengthening and can better protect the multi-beam generator with electronic devices and / or circuits located thereon, for example, from the x-ray radiation occurring. In this embodiment variant, the beam current meter is also able to determine the beam current directly or indirectly. In the case of this embodiment variant, it is also possible in principle to record or monitor the beam current with spatial resolution.

[0065] The above-mentioned embodiment variants according to the first aspect of the invention can all or in part be combined with one another, as long as no technical contradictions arise as a result.

[0066] According to a second aspect of the present application, the present application relates to a system comprising the following: a multi-beam particle microscope as described before in various embodiments, having a replacement module,

[0067] at least one further replacement module for the multi-beam particle microscope; and

[0068] a housing having at least one vacuum-tight connector for the at least one further replacement module,

[0069] wherein the housing is configured to store the further replacement module inside the housing under high vacuum, in particular under ultra-high vacuum, when the first sealing element of the further replacement module is open. In this case, the replacement module and the further replacement module are preferably structurally identical. The replacement module can be pre-characterized and / or pre-adjusted before bringing the at least one further replacement module into the housing. This can save a significant amount of time when changing the particle source in the multi-beam particle microscope. Furthermore, in the case of the housing, the at least one further replacement module can already be evacuated and / or baked and thus reduce the evacuation and baking time, which is significant during the particle source change or this is performed before the actual replacement of the particle source. The at least one vacuum-tight connector in the housing is dimensioned such that the replacement module or the first part module of the double-sealing and column separation module can be connected thereto in a vacuum-tight manner. Preferably, the housing-side connector has the same dimensions and sealing properties as the second part module of the double-sealing and column separation module, which remains on the remaining column of the illumination column when the particle source is replaced. However, different embodiments are also possible as long as there are corresponding connection options and the required sealing properties.

[0070] According to a third aspect of the present application, in accordance with the above-mentioned embodiments, the present application relates to a method for replacing a particle source in a multi-beam particle microscope. In this case, the multi-beam particle microscope comprises a replacement module as described before and the method comprises the following steps:

[0071] closing the first sealing element and the second sealing element of the double-sealing and column separation module;

[0072] breaking the vacuum in the region between the first sealing element and the second sealing element in the double-sealing and column separation module;

[0073] spatially separating the double-sealing and column separation module into a first part module and a second part module, thereby separating the first replacement module comprising the first particle source from the remaining part of the multi-beam particle microscope or the remaining illumination column;

[0074] a second replacement module containing a second particle source is arranged on the remaining part of the multi-beam particle microscope or on the remaining illumination column, so that the second double-sealing and column-separation module is combined with the first double-sealing and column-separation module, wherein the second replacement module has been evacuated, and wherein the first sealing element is closed;

[0075] the second double-sealing and column-separation module is evacuated between its first sealing element and its second sealing element;

[0076] after the evacuation, the first sealing element of the second double-sealing and column-separation module and the second sealing element of the second double-sealing and column-separation module are opened.

[0077] The terms used herein in the context of the method according to the application are identical to the terms already used and defined above in the context of the multi-beam particle microscope or in the context of the system. The described method describes the replacement of a first replacement module containing a first particle source by a second replacement module containing a second particle source using the double-sealing and column-separation module. The double-sealing and column-separation module is spatially divisible into the first part module and the second part module. In the context of this method, as described above, the double-sealing and column-separation module is reassembled as it is: the second part module remains the same, while the first part module, as it is considered to be part of the replacement module, is replaced. Thus, the first double-sealing and column-separation module is the originally existing double-sealing and column-separation module, while the second double-sealing and column-separation module is the newly assembled double-sealing and column-separation module. The corresponding statements apply to a possible third replacement module with a third particle source and a third double-sealing and column-separation module assembled or assemblable therefrom.

[0078] According to a preferred embodiment variant of the method, the method further comprises the step of heating the first and / or second double-sealing and column-separation module. Such heating can be carried out in the case of the double-sealing and column-separation module being installed in the multi-beam particle microscope, and can also be maintained during normal operation of the multi-beam particle microscope. In addition or alternatively, a part of the double-sealing and column-separation module located in the accommodation can also be heated in order to be able to evacuate the entire replacement module in the accommodation more quickly and / or more sustainably. To this end, the first sealing element is opened in the accommodation.

[0079] According to a further preferred embodiment variant of the method, the method further comprises the step of pre-adjusting or technically pre-characterizing the second replacement module before configuring the second replacement module on the remaining part of the multi-beam particle microscope. This is one of the main advantages of the method according to the application or of the multi-beam particle microscope according to the application: the pre-adjustment and / or technical pre-characterization can save valuable time during the replacement of the particle source. The technical pre-characterization and / or pre-adjustment can comprise the establishment of an ultra-high vacuum (bake-out evacuation), the running-in of the tip cathode (high-voltage adjustment), the characterization of the tip cathode emission properties and the adjustment of the electron beam to be aligned with the optical axis.

[0080] According to a further preferred embodiment of the application, the method further comprises the step of storing the second replacement module in a storage in a vacuumized state. Thus, the second replacement module can be quickly used or can replace the first replacement module. For example, the storage itself can be located in the same room as the multi-beam particle microscope; however, it can also be located in an adjacent room or at least in the same building. The shorter the path between the storage and the multi-beam particle microscope, the faster the overall replacement process of the particle source progresses. Furthermore, possible adjustment losses during the transport of the second replacement module to the multi-beam particle microscope are avoided. However, the storage can of course also be located at a greater distance compared to the multi-beam particle microscope. In this case, the storage itself can be implemented for a relatively long time, for example several months or years. During this time, the vacuum within the stored replacement module is preferably maintained at all times; the first sealing element is preferably kept open at all times.

[0081] According to a further preferred embodiment of the application, the method further comprises the step of:

[0082] configuring the second replacement module isostatically on the remaining part of the multi-beam particle microscope or of the illumination column; and / or

[0083] adjusting the second replacement module by means of an adjustment; and / or

[0084] adjusting the second replacement module by means of an electric and / or magnetic deflection field which deflects the charged particles and / or the charged first individual particle beams.

[0085] In this context, the isostatic configuration of the second replacement module on or against the remaining part of the multi-beam particle microscope without the need to perform a further adjustment process represents an ideal case.

[0086] The adjustment of the second replacement module by the adjustment means essentially describes a mechanical adjustment or an adjustment with mechanical components, wherein, for example, the second replacement module is displaceable, rotatable and / or tiltable compared to the remaining part of the multi-beam particle microscope. If the second replacement module is adjusted by electric and / or magnetic deflection fields, additional mechanical adjustments can be dispensed with. However, the latter can also be required in addition. Examples of the adjustment of the second replacement module by means of electric and magnetic deflection fields are, for example, the modified control of one or more condenser lenses and / or electric and / or magnetic deflection or double deflection devices arranged in the condenser lens system. One or more further electric and / or magnetic deflection devices can also be provided specifically for adjustment purposes.

[0087] According to a further preferred embodiment of the application, the method further comprises the steps of:

[0088] monitoring a current pattern in the particle source region; and

[0089] adjusting the relationship of the components of the particle source relative to each other on the basis of the current pattern.

[0090] For example, the components of the particle source can be the cathode tip, the extraction diaphragm and the anode diaphragm, which should be aligned flush with each other. In this context, the monitoring of the current pattern in the particle source region can be carried out, for example, on the extraction diaphragm and / or the anode diaphragm; in particular, the current pattern can be recorded with spatial resolution. In this case, the current pattern can be used particularly well for adjustment purposes.

[0091] According to a further preferred embodiment of the application, the method further comprises the steps of:

[0092] monitoring a current pattern in the particle source region; and

[0093] predicting the remaining useful life of the particle source and, in particular, initiating the replacement of the particle source on the basis of the current pattern in each case. In principle, it is known that the emission properties of the particle source change over the course of the useful life of the particle source and how they generally change. Thus, changes in the particle source can be observed by monitoring the current pattern during operation of the multi-beam particle microscope. On this basis, the remaining useful life of the particle source can be predicted and, in particular, the replacement of the particle source can also be initiated in good time.

[0094] Alternatively or in addition, the remaining useful life of the particle source can also be derived from other current measurements. Indications in this regard can also be derived from, for example, beam current measurements on the first multi-aperture plate of the multi-beam generator. Details in this regard can be gathered from the document WO 2023 / 001402 A1 cited at the outset, the disclosure of which is incorporated by reference in its entirety into the present patent application for reference.

[0095] According to a further preferred embodiment of the present application, the method is performed multiple times, in whole or in part, wherein, in particular, a third replacement module with a third particle source and / or a further replacement module with a further particle source is configured on the remaining part of the multi-beam particle microscope or on the remaining illumination column. For example, the method can be performed until all replacement modules stored in the accommodation have actually been installed in the multi-beam particle microscope. Furthermore, it is also possible in principle to fill the accommodation with further replacement modules at the same time and thus to perform the method according to the present application for any desired length of time.

[0096] According to a fourth aspect of the present application, the present application relates to a multi-beam particle microscope with replaceable particle sources, having the following features:

[0097] a first vacuum region with a first particle source configured in an operating position and configured to emit charged particles;

[0098] a multi-beam generator configured to generate a first field of a plurality of charged first individual particle beams from the charged particles;

[0099] a first particle-optical unit with a first particle beam path configured to image the generated first individual particle beams onto a sample surface in an object plane such that the first particle beams are incident on the sample surface at an incidence position, the incidence position forming a second field;

[0100] a detection system with a plurality of detection regions forming a third field;

[0101] a second particle-optical unit with a second particle beam path configured to image second individual particle beams emanating from the incidence position in the second field onto the third field of the detection regions of the detection system;

[0102] a magnetic and / or electrostatic object lens, both the first and the second individual particle beams passing through the object lens;

[0103] a beam splitter configured in the first particle beam path between the multi-beam generator and the object lens and configured in the second particle beam path between the object lens and the detection system;

[0104] a sample stage for holding and / or positioning a sample during sample examination;

[0105] a controller configured to control the multi-beam particle microscope;

[0106] a second vacuum region with a storage unit, the storage unit accommodating at least one second particle source identical in structure to the first particle source as a replacement particle source; and

[0107] a transport mechanism for vacuum-transporting the second particle source from the storage unit of the second vacuum region to the operation position in the first vacuum region.

[0108] In this context, the operation position is understood to be the position of the particle source in the multi-beam particle microscope in which the particle source is configured during operation of the multi-beam particle microscope. In this embodiment of the invention, the operation position is not the storage position in which only the particle source is stored. Thus, in this embodiment of the invention, the operation position is different from the storage position. In contrast, one or more such storage positions are found in the storage unit.

[0109] According to this embodiment of the invention, the active particle source, i.e. the particle source in operation or currently provided for operation, is in a vacuum region. Thus, the operation position is located in a vacuum region, in particular the first vacuum region. Likewise, the storage unit with at least the second particle source as replacement particle source is also located in a vacuum, in particular in the second vacuum region. Thus, the storage position is located in a vacuum region. In this context, the first vacuum region and the second vacuum region can be formed as two vacuum chambers separate from one another. For example, they can be separated from one another by a gas lock. However, the first vacuum region and the second vacuum region can also be configured in the same vacuum chamber, i.e. without one or more gas locks interposed. It can also be that the second vacuum region consists of a plurality of vacuum chambers. The effect is the same: in this variant of the embodiment of the invention, the replacement of the particle source can be carried out completely in a vacuum. Thus, it can not be necessary to evacuate the vacuum chamber and the necessary vacuum chamber baking, etc. The particle source can thus be replaced more quickly.

[0110] In this embodiment of the invention, the transport mechanism is configured for vacuum-transporting the second particle source from the storage unit of the second vacuum region to the operation position in the first vacuum region. In this context, it is also possible that the transport mechanism is configured for vacuum-transporting the first particle source from the operation position in the first vacuum region into the storage unit of the second vacuum region, optionally also essentially. Thus, not only can the replacement particle source be brought into the operation position, but the old particle source can also be completely removed from the operation position in a vacuum. In this context, the transport mechanism itself can have a single-part or multi-part design. For example, one or more transport rods can be used for the transport under vacuum conditions. For example, the actuation of the transport rods can be carried out manually or in an automated manner by means of suitable motors and / or sensor systems. Furthermore, the transport mechanism can comprise mechanical positioning means, such as guides, positioning pins, screws or clamps.

[0111] The particle source itself can comprise a unit made of a plurality of component parts, such as a cathode tip, an extraction aperture and an anode aperture. It can also comprise a suppression electrode at the same time. However, it can also consist only of a cathode tip. In this embodiment according to the fourth aspect of the application, the replacement particle source as a unit is preferably smaller than the replacement module according to the first aspect of the application. This is because, since the replacement particle source is already in the vacuum, it is not necessary to replace the housing part at the same time which accommodates the particle source and maintains the vacuum around the particle source. Furthermore, it is important in the context of this embodiment variant that the storage space for one or more replacement particle sources is kept as small as possible in order to be able to accommodate as many replacement particle sources as possible in the storage unit. However, this will preferably be the case with a replacement unit which is pre-equipped with a plurality of component parts, such as a cathode tip, an extraction aperture and an anode aperture, and optionally a suppression electrode, since in this case the component parts of the replacement particle source can be pre-equipped before the actual replacement of the particle source in the vacuum. In other words, the storage unit only comprises a replacement particle source which has been pre-identified and / or pre-adjusted as a future replacement particle source. This facilitates a subsequent exact positioning and adjustment of the replacement particle source in the operating position after the particle source replacement and this in turn saves time.

[0112] According to a preferred embodiment of the application, the storage unit comprises a plurality of storage positions or storage spaces for the replacement particle source which are arranged according to a physical linear layout. For example, in this embodiment variant a storage bus system can be used as the storage unit, which system can be moved, for example, on a platform in the Z direction. It is also conceivable to use a transport bar to move the storage bus system. In any case, it is applicable in this embodiment variant that the replacement particle source can be brought to its initial position by linear movement by means of a suitable movement mechanism for subsequent transfer from the second vacuum region into the first vacuum region.

[0113] According to an alternative embodiment of the application, the storage unit has a plurality of storage positions or storage spaces for the replacement particle source which are arranged according to a physical star-shaped layout. Thus, it is applicable in this embodiment variant that the storage positions are arranged, for example, in a ring, wherein the replacement particle source can then be brought into the centre of the ring for transport to the operating position. In other words, the operating position of the respective active particle source is located in the centre between the storage positions of the storage unit. Since the replacement particle source is introduced in each case into the centre of the layout, reference is made in this context also to a star-shaped layout instead of, for example, a ring-shaped layout. For example, in this embodiment variant the transport mechanism itself can comprise a plurality of transport bars, wherein the plurality of transport bars preferably corresponds to the number of storage positions. In other words, it is applicable that a respective transport bar is used for the transport from the storage position to the operating position. In this embodiment variant, the operating position itself can be approached from different directions.

[0114] According to an alternative embodiment of the application, the storage unit has a plurality of storage positions or storage spaces for the replacement particle source, which are arranged according to a physical ring layout. In this embodiment, the replacement particle source is moved along the ring for the purpose of particle source replacement. In this case, the operating position is located on the ring. This layout can be realized, for example, by means of a rotating mechanism, for example a rotating table with the replacement particle source in a high vacuum.

[0115] According to a further preferred embodiment of the application, the multi-beam particle microscope also comprises the following:

[0116] a contact unit for electrically contacting the respective active particle source in the operating position; and

[0117] an adjustment unit for fine positioning of the respective active particle source in the operating position.

[0118] In this case, the contact unit can have a single-part or multi-part design. The electrical contacting can comprise one or more contact points. For example, a separate contact can be provided for each electrode of the particle source. This contact unit can be moved relative to the operating position, for example by means of a platform which can be moved in one direction. For example, a connector with a plurality of electrical contact points can be realized in this way and the replacement particle source can thus be connected. In principle, the electrical contacting can be established within the vacuum by means of a connector, a clamp and / or a sliding contact.

[0119] In this case, the adjustment unit for fine positioning of the respective active particle source in the operating position can also have a single-part or multi-part design. It can be realized in different ways, for example by means of a 3D platform and / or by means of piezoelectric elements. Other embodiments are also possible here.

[0120] According to a preferred embodiment of the application, each replacement particle source comprises a tip cathode, an extraction electrode and an anode, which have been adjusted and / or technically pre-certified relative to one another. In this embodiment variant, therefore, fine tuning of the constituent parts of the replacement particle source relative to one another can largely or completely be dispensed with, and this saves time.

[0121] According to a fifth aspect of the application, the application relates to a multi-beam particle microscope with replaceable particle sources, which has the following features:

[0122] a plurality of structurally identical particle sources, which are fixedly arranged in space, each particle source being arranged to emit charged particles;

[0123] a switching member, which is arranged to switch between the particle sources such that at any time, in each case, only one of the particle sources is an active particle source which emits charged particles;

[0124] an electric and / or magnetic deflection member configured to deflect the charged particles emitted by the respective active particle source onto an optical axis of the multi-beam particle microscope;

[0125] a multi-beam generator configured to generate a first field of a plurality of charged first individual particle beams from the charged particles of the particle source;

[0126] a first particle optical unit having a first particle beam path configured to image the generated first individual particle beams onto a sample surface in an object plane such that the first individual particle beams are incident on the sample surface at an incidence position, the incidence position forming a second field;

[0127] a detection system having a plurality of detection areas forming a third field;

[0128] a second particle optical unit having a second particle beam path configured to image second individual particle beams emanating from the incidence position in the second field onto the third field of the detection areas of the detection system;

[0129] a magnetic and / or electrostatic objective lens, both the first and the second individual particle beams passing through the objective lens;

[0130] a beam splitter configured in the first particle beam path between the multi-beam generator and the objective lens and configured in the second particle beam path between the objective lens and the detection system;

[0131] a sample stage for holding and / or positioning a sample during sample inspection;

[0132] a controller configured to control the particle source, the switching member and the deflection member. Of course, the controller can also control the multi-beam particle microscope as a whole. As always, the controller itself can have a single component or a multi-component design.

[0133] This embodiment of the present application does not require a transport mechanism for transporting the particle source. Instead, the active particle source and the replacement particle source are fixedly arranged in space (under vacuum) in the multi-beam particle microscope. Thus, in this embodiment variant, there is a switching between the particle sources instead of a mechanical transfer. In principle, this embodiment variant thus comprises a plurality of mutually different operating positions, which are also intermittent storage positions. In order to enable a precise coupling of the emitted charged particles from each of these operating positions to the illumination column of the multi-beam particle microscope, electrical and / or magnetic deflection means are provided. In the present context, the deflection means can have a single-part or multi-part design. This embodiment variant of the present application also allows for a quick replacement or change of the particle source, since the replacement of the particle source does not require a destruction of the vacuum, a re-evacuation of the multi-beam particle microscope, nor a re-baking. Moreover, the fixed spatial arrangement of the particle source also makes it possible to dispense with a fine-tuning of the particle source itself in the context of the replacement of the particle source. Instead, each particle source can be independently adjusted during the initial adjustment of the multi-beam particle microscope. In principle, of course, further means for a subsequent fine-tuning can also be provided, as already described in the context of the other embodiment variants of the present application.

[0134] The switching means for switching between the particle sources can for example be a selection button or a selection display; however, the switching means can also be implicitly set or integrated in the controller of the multi-beam particle microscope. For example, an automatic switching can be precisely carried out when the particle source needs to be replaced.

[0135] According to a preferred embodiment of the present application, the multi-beam particle microscope comprises exactly four particle sources, which are arranged opposite to each other in pairs and are configured such that each of the particle sources is capable of emitting charged particles orthogonal to the optical axis of the multi-beam particle microscope. In other words, the charged particles emitted from the particle sources are not emitted directly in the direction of the optical axis of the multi-beam particle microscope, but at 90°, that is to say from the side. In this embodiment variant of the present application, the switching means comprise two pairs of Helmholtz coils, thus a total of four coils, wherein in each case only one pair of Helmholtz coils is activated at any one time. Furthermore, the respective coils are arranged between one of the particle sources and the imaginary extension of the optical axis of the multi-beam particle microscope. Thus, in this case the sequence particle source - coil of the Helmholtz coil pair - imaginary extension of the optical axis of the multi-beam particle microscope is implemented four times in each case. The axes of the Helmholtz coil pairs themselves are arranged orthogonal to the optical axis of the multi-beam particle microscope (or its imaginary extension), such that the magnetic fields generated by the Helmholtz coil pairs, respectively, are oriented orthogonal to the optical axis of the multi-beam particle microscope. Furthermore, the controller is configured to control the Helmholtz coil pairs in such a way that the charged particles emitted by the respective active particle source are deflected or reoriented in the direction of the optical axis of the multi-beam particle microscope.

[0136] In this embodiment of the present application, the particle source preferably comprises a cathode tip, an extraction aperture and an anode aperture and optionally a suppression electrode.

[0137] According to an alternative embodiment of the present application, the multi-beam particle microscope comprises exactly four particle sources, which are arranged opposite to each other in pairs and in each case at an inclination angle a ≠ 0°, in particular 40° ≤ a ≤ 50°, preferably a = 45°, with respect to the optical axis of the multi-beam particle microscope. Compared to the above-mentioned embodiment variant with two pairs of Helmholtz coils, the four particle sources are thus inclined in the direction of the optical axis of the multi-beam particle microscope. In this embodiment of the present application, the deflection means comprise four deflection electrodes, each assigned to one particle source. The deflection electrodes can be identical to the four anodes of the four particle sources; however, separate deflection electrodes can also be provided. In particular, the deflection electrodes can be configured as deflection electrode diaphragms. These electrode diaphragms can be configured parallel to the anode diaphragms or extraction diaphragms of the particle sources, for example. In this embodiment variant of the present application, the controller is likewise configured to control the deflection electrodes of the particle source opposite the active particle source in each case using a deflection potential, such that the charged particles emitted by the respective active particle source are deflected or redirected in the direction of the optical axis of the multi-beam particle microscope. In addition, a voltage for adjustment in the lateral direction can be applied to the other two deflection electrodes, which are not assigned to the active particle source and also not to the particle source directly opposite the active particle source. This embodiment of the present application thus also completely dispenses with the need for transport particle sources. Ideally, no mechanical adjustment is also required in the replacement range of the particle sources. Rather, electric fields are used for switching and optionally (fine) adjustment. This replacement of the particle sources can thus also be carried out very quickly and very precisely.

[0138] The above-mentioned embodiments of the present application can all or in part be combined with each other within one aspect of the present application and in the manner of the overall aspect, as long as no technical contradictions arise therefrom. BRIEF DESCRIPTION OF DRAWINGS

[0139] The present application will be better understood with reference to the accompanying drawings. In the drawings:

[0140] Figure 1 Schematic illustration of a multi-beam particle microscope;

[0141] Figure 2 Schematic illustration of a cross-sectional view of a double-sealing and column separation module;

[0142] Figure 3 Schematic illustration of a spatial view of a double-sealing and column separation module;

[0143] Figure 4 Schematic illustration of an illumination column and a double-sealing and column separation module in a multi-beam particle microscope;

[0144] Figure 5 Schematic illustration of various configurations of a double-sealing and column separation module in a multi-beam particle microscope;

[0145] Figure 6 Schematic illustration of replacement of a particle source;

[0146] Figure 7 Schematic illustration of a part of a multi-beam particle microscope with replaceable particle sources, wherein the replaceable particle sources are arranged in a storage unit;

[0147] Figure 8 Schematic illustration of a part of a multi-beam particle microscope with replaceable particle sources, wherein the replaceable particle sources are arranged in a storage unit;

[0148] Figure 9 Schematic illustration of a part of a multi-beam particle microscope with replaceable particle sources, wherein the replaceable particle sources are arranged in a storage unit;

[0149] Figure 10 Schematic illustration of a part of a multi-beam particle microscope with replaceable particle sources, wherein the replacement is performed by switching;

[0150] Figure 11 Schematic illustration of a part of a multi-beam particle microscope with replaceable particle sources, wherein the replacement is performed by switching;

[0151] Figure 12 Schematic illustration of a part of a multi-beam particle microscope with replaceable particle sources, wherein the replacement is performed by switching;

[0152] Figure 13 Schematic illustration of a multi-beam particle source and its position dependence of the current strength;

[0153] Figure 14 Schematic illustration of a current mode acquisition of an anode aperture, which can be used for fine tuning of a particle source;

[0154] Figure 15 Schematic plan view of an overlay element which can be inserted into the beam path;

[0155] Figure 16 Schematic cross-sectional representation of an overlay element which can be inserted into the beam path;

[0156] Figure 17 Schematic cross-sectional view of a double-sealing and column separation module with a filling volume;

[0157] Figure 18 Schematic illustration of a foldable shielding element for sealing;

[0158] Figure 19 Schematic space view of a double-sealing and column separation module with a foldable shielding element for sealing; and

[0159] Figure 20Differential pumping is schematically shown in the context of a double-sealing and column separation module. DETAILED DESCRIPTION

[0160] Figure 1 A multi-beam particle microscope 1 is schematically shown. The multi-beam particle beam system 1 comprises a beam generating device 300 with a particle source 301, for example an electron source. A divergent particle beam 309 is collimated by a series of condenser lenses 303.1 and 303.2 and impinges on a multi-aperture arrangement 305. The multi-aperture arrangement 305 comprises a plurality of multi-aperture plates 306 and a field lens 308. A plurality of individual particle beams 3 or individual electron beams 3 is generated by the multi-aperture arrangement. The center points of the apertures in the multi-aperture plate arrangement are arranged in a field which is imaged onto a further field formed by the beam spots 5 in the object plane 101. The distance between the center points of the apertures of the multi-aperture plate 306 can be, for example, 5 μιη, 100 μιη and 200 μιη. The diameter D of the apertures is smaller than the pitch of the center points of the apertures; examples of diameters are 0.2 times, 0.4 times and 0.8 times the distance between the center points of the apertures.

[0161] The multi-aperture arrangement 305 and the field lens 308 are configured to generate a plurality of focal points 323 of the primary beams 3 in a raster arrangement on a surface 321. The surface 321 is not necessarily planar, but can be a spherical surface to take into account the image field curvature of the subsequent particle optical system.

[0162] The multi-beam particle microscope 1 further comprises a system of electromagnetic lens systems 103 and an objective 102 which image the beam foci 323 from an intermediate image surface 325 into the object plane 101 with reduced dimensions. In between, the first individual particle beams 3 pass through a beam splitter 400 and a beamlet deflection system 500 by which the plurality of first individual particle beams 3 are deflected and scanned over the image field during operation. The first individual particle beams 3 which are incident into the object plane 101 form, for example, a substantially regular field in which the distance between adjacent incident positions 5 can be, for example, 1 μιη, 10 μιη or 40 μιη. By way of example, the field formed by the incident positions 5 can have rectangular or hexagonal symmetry.

[0163] The object 7 to be inspected can be of any type, for example a semiconductor wafer or a biological sample, and comprises an arrangement of miniaturized elements or the like. A surface 15 of the object 7 is arranged within the object plane 101 of the objective 102. The objective 102 can comprise one or more electron optical lenses. For example, this can be a magnetic objective and / or an electrostatic objective.

[0164] Primary particles 3 are incident on object 7, generating interaction products such as secondary electrons, backscattered electrons, or primary particles undergoing reverse motion due to other factors. These interaction products exit from the surface of object 7 or from the first plane 101 or object plane 101. The interaction products generated from the surface 15 of object 7 are shaped by objective lens 102 to form secondary particle beam 9. In this process, the secondary beam 9 passes through a beam splitter 400 downstream of objective lens 102 and is provided to projection system 200. Projection system 200 includes imaging system 205 having projection lenses 208, 209, and 210, a contrast stop 214, and a multi-particle detector 207. The second individual particle beam 9 is incident at a regular interval 25 in the detection area of ​​multi-particle detector 207 within a third field. Example values ​​are 10 µm, 100 µm, and 200 µm.

[0165] The multibeam particle microscope 1 also includes a computer system or control unit 10, which may have a single component or multiple component design and is designed to control the individual particle optics components of the multibeam particle microscope 1 and to evaluate and analyze the signals obtained by the multiple detectors 207 or detection units.

[0166] Further information relating to this multi-beam particle system or multi-beam particle microscope 1 and the components used herein, such as, for example, particle sources, perforated plates and lenses, can be obtained from international patent applications WO 2005 / 024881 A2, WO 2007 / 028595 A2, WO 2007 / 028596A1, WO 2011 / 124352 A1 and WO 2007 / 060017 A2, and German patent applications DE 10 2013 016 113A1 and DE 10 2013 014 976 A1, which are incorporated herein by reference in their entirety.

[0167] Figure 2 The schematic diagram shows a cross-sectional view of the dual-seal and column separation module 710, which can be integrated into... Figure 1 In the multi-beam particle microscope shown, a double-sealed and column separation module 710 is configured within the illumination column of the multi-beam particle microscope 1. In this case, Figure 2 Only a portion of the illumination column is shown. A housing 708 with a first beam tube portion 704 and a housing 709 with a second beam tube portion 705 are shown. The beam tube 703 is subdivided into two beam tube portions 704 and 705 by a double-seal and column separation module 710. During operation of the multi-beam particle microscope 1, or in the installed state, the double-seal and column separation module 710 is sealed between the two beam tube portions 704 and 705, and charged particles or the first individual particle beam 3 (charged particles and the first individual particle beam 3 in...) are... Figure 2(Not explicitly shown) passes through the double seal and column separation module. The sealing surface 706 for the sealing configuration passes through... Figure 2 An example is illustrated below. In this case, the aim is to ensure the high vacuum required for the operation of the multi-beam particle microscope even within the installed double-sealed and column separation module 710. When the multi-beam particle microscope 1 is not in operation, the double-sealed and column separation module 710 can be spatially divided into a first part module 711 and a second part module 712. For this purpose, the double-sealed and column separation module 710 can be appropriately accessed from the outside, so that the first part module 711 and the second part module 712 are spatially separable, for example, by loosening the connection of a screw. An intermediary or adapter 713 can be configured between the first part module 711 and the second part module 712. However, this adapter 713 may also belong to the second part module 712, which is located in... Figure 2 The figure is indicated by reference numeral 712' in the attached map (see also...) Figure 4 (b) The first part module 711 includes a first sealing element 714, which, when spatially separated from the second part modules 711 and 712, is configured to seal and enclose the adjacent beam tube portion 704 on the particle source side. The second part module 712 includes a second sealing element 715, which, when spatially separated from the first part modules 711 and 712, is configured to seal and enclose the adjacent beam tube portion 705 on the beam splitter side. Sealing elements 714 and 715 in... Figure 2 The image depicts it as being in a closed position. Therefore, the beam tube 703 is vacuum-sealed in each case by components of sealing elements 714 and 715. The sealing elements, in a narrower sense, are... Figure 2 Reference numerals 714a and 715a are used to indicate this. In this case, the sealing elements 714 and 715 can be implemented in different ways. For example, the first sealing element 714 and / or the second sealing element 715 of the dual-seal and column separation module 710 may comprise an ultra-high vacuum slider, a valve 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 be manually, pneumatically, or electrically operated. According to one example, the dual-seal and column separation module 710 is configured to achieve 10 -10 Millibars or better ultra-high vacuum. Additionally or alternatively, according to one example, the dual-seal and column separation module 710 is configured to achieve less than or equal to 10... -9 Leakage rate in mbar / l / s.

[0168] To achieve a vacuum or high vacuum during operation, the double-sealed and column separation module 710 includes an inlet 717 located in an intermediate region 716 between the first sealing element 714 and the second sealing element 715. Therefore, the intermediate region 716 is evacuable for operation of the multibeam particle microscope 1, and the vacuum in the intermediate region 716 can be disrupted due to the separation of the first part module 711 and the second part module 712 (see also...). Figure 4 b). In Figure 2 In the example shown, inlet 717 is achieved through a simple drilled hole. However, multiple drilled holes or inlets with different designs can also be achieved. In the example shown, drilled hole 717 connects to a vacuum-sealed line 718. The latter may be connected to or has been connected to a vacuum pump (not depicted).

[0169] Figure 17 A schematic cross-sectional view of a double-sealed and column separation module 710 with a filler volume 707 is shown. This filler volume 707 is used to reduce the volume below which a vacuum should be generated in the double-sealed and column separation module 710. For example, the filler volume 707 may contain titanium or be composed of titanium. Furthermore, the filler volume 707 (especially a filler volume containing titanium or composed of titanium) has the advantage of acting as a barrier to prevent the propagation of scattered radiation or scattered electrons, specifically in the second part of the double-sealed and column separation module 710, module 712, and in the region or module of the multi-beam particle microscope 1 disposed below it in the direction of the particle beam path. It also reduces the charging of the seals. In the example shown, the filler volume 707 has a through-hole with a diameter d2 smaller than the diameter dl of the beam tube 703. This dimensional design also helps to reduce scattered radiation.

[0170] Figure 3 The schematic diagram shows a spatial view of the double-sealed and column separation module 710. In the example shown, the housings 708 and 709 of the lighting column are substantially tubular. The beam tube portions 704 and 705 of the beam tube 703 are respectively disposed within the housings 708 and 709. However, for clarity, in Figure 3 The actual beam tube sections 704 and 705, which extend in the illumination columns on the particle source side and beam splitter side respectively, are not explicitly depicted in this manner. Instead, Figure 3 A perspective view illustrates the basic setup of the double-seal and column separation module 710 and its integration into the lighting column. The first part module 711 of the double-seal and column separation module 710 is disposed on the housing 708, and also on the beam tube 703 disposed therein, or on the beam tube portion 704 disposed therein. In this case, the connection between the housing portion 708 and the first part module 711 is flange-shaped, wherein the sealing surface 706 is... Figure 3is particularly important, especially in the region of the beam tube 703. The second partial module 712 is connected to the first partial module 711 via a further sealing surface 706. The second partial module 712 is then sealingly connected to the housing 709, or the beam tube 703 or the associated beam tube section 705 located therein. In the depicted example, a first sealing element 714 and a second sealing element 715 are implemented by ultra-high vacuum slides. For sealing, the partial elements 714a and 715a are pushed or slid, for example, into an intermediate region 716 of the double-sealing and column separation module 710 to achieve a vacuum-tight closure. This is shown in Figure 3 B. In particular, this figure shows a sectional view of the double-sealing and column separation module 710. The double-sealing and column separation module 710 comprises an inlet 717 in the form of a bore in the intermediate region 716 between the first sealing element 714 and the second sealing element 715. A vacuum-sealing line (not shown) can be connected to this bore 717, and the former can be connected or has been connected to a vacuum pump (not shown). In the example shown, the inlet 717 itself is integrated in the first partial module 711 in this case. However, it is also possible for the inlet 717 not to be arranged in the first partial module 711, but for example in an intermediate piece or adapter between the two partial modules 711, 712. In principle, it is advantageous if the double-sealing and column separation module 710 comprises as few separate component parts or modules as possible, since this allows better handling of the sealing problems associated with the generation and maintenance of ultra-high vacuum. In contrast, the argument for an adapter piece is that this allows the first partial module 711 and the second partial module 712 to be manufactured in identical construction.

[0171] The double-sealing and column separation module 710 can comprise or consist of an electrically conductive material, and for its relative magnetic permeability μ r the following applies: μ r ≤ 1.005. Thus, during operation of the multi-beam particle microscope, the particle beams passing through the double-sealing and column separation module 710 are not disturbed, and the double-sealing and column separation module is not charged or magnetized. It is therefore also advantageous for the sealing surface 706 arranged in the region of the intermediate region 716, i.e. in the interior of the double-sealing and column separation module 710, to be slightly recessed from the cavity 716 or to shield the sealing surface 706 from the cavity 716, in order to avoid potential charging of the sealing surface 706.

[0172] Figure 18Foldable shielding elements 722, 723 for the seal 726 are schematically shown. The seal 726 can comprise, for example, a fluoroelastomer, for example known under the trademark Viton®. An advantage of using a seal 726 made of a fluoroelastomer, such as Viton®, is, for example, that the sealing process requires a lower contact pressure than in the case of a metal seal. Furthermore, such a seal is relatively soft and elastic, which puts lower requirements on the mechanical tolerances in the sealing area and on the surface roughness there. The shielding elements 722, 723 are composed of metal. The foldable shielding elements 722, 723 comprise an upper area 724 and a lateral area 725, resulting in a housing or garage type for the seal 726. If the valve of the double seal and column separation module 710 is open or if the multi-beam particle microscope 1 is evacuated and in operation (see Figure 18 a), the shielding elements 722, 723 are closed. Thus, the seal 726 can be protected from charging during operation. Potential scattered radiation, for example scattered electrons, can be captured and diverted by the metal shielding elements 722, 723. When the seal 726 is used for double sealing and column separation, the seal is only free outside the shielding elements 722, 723. When the valve of the double seal and column separation module 710 is closed, or if the double seal and column separation module 710 is separated or should be separated into the first partial module 711 and the second partial module 712 (see Figure 18 b), the shielding elements 722, 723 are open.

[0173] Figure 19 A spatial diagram of the double seal and column separation module 710 with foldable shielding elements 722, 723 for the seal 726 (not explicitly drawn in Figure 19 ) is schematically shown. The housing features or garage features of the foldable shielding elements 722, 723 are easily visible in the spatial diagram.

[0174] Figure 20Differential pumping is schematically shown in the case of the double-seal and column separation module 710. If a seal made of fluoro rubber or fluoro elastomer is used for the seal 726 in the separation plane T of the double-seal and column separation module 710, this seal 726 has very good sealing properties, but still has a higher leakage rate than a metal seal. This increase in the leakage rate can lead to an increase in the UHV end pressure. In order to minimize or ideally eliminate this problem, it is proposed to use differential pumping in the separation plane T; this reduces the leakage rate due to the reduced pressure gradient. For this purpose, a further seal 727 is provided, which can be made of the same material as the seal 726. Thus, in addition to the volume V1 to be evacuated, at least one additional pressure stage with the volume V2 is created in the region between the two seals 726, 727. The volume V1 is connected to a pump (not shown) via the line 729; the volume V2 is connected to a pump (not shown) via the line 728. The volumes V3 and V4 are schematically depicted and assigned to the evacuation volumes within the column, above and below the double-seal and column separation module 710, respectively.

[0175] Figure 4 The illumination column 700 of the multi-beam particle microscope 1 and the double-seal and column separation module 710 are schematically shown in a schematic view. In this case, the housings 708, 709 of the illumination column 700 are only schematically depicted as outlines. The particle-optical components are located within the housings, as already described in detail in Figure 1 . Basically, the order of the particle-optical components within the illumination column 700 is, for example, as follows: At the top, a particle source 301 is arranged within the illumination column 700 or the housing part 708. In the example shown, a condenser lens system with, for example, two magnetic condenser lenses 303.1 and 303.2 is located thereunder. A multi-beam generator 305 is arranged thereunder in the particle beam path. Thereunder, a first field lens 308 is arranged in sequence, and further field lenses 103 are arranged thereafter. A beam splitter 400 is located even further down in the particle beam path.

[0176] There are various options regarding the position at which the double-seal and column separation module 710 can be arranged in the illumination column 700: Figure 5 Various possible arrangements of the double-seal and column separation module 710 in the multi-beam particle microscope 1 or within the illumination column 700 are schematically shown:

[0177] According to Figure 5In the exemplary embodiment shown in A, the double-sealing and column separation module 710 is configured within the condenser lens system 303, or, in this context, between the first special magnetic condenser lens 303.1 and the second special magnetic condenser lens 303.2. As such, the illumination column 700 is subdivided into a head of the illumination column 701 and a remaining illumination column 702 or remaining column 702. The head of the illumination column 701 also always contains the particle source 301, which in this case forms the replacement module 701. The configuration of the double-sealing and column separation module 710 in the shown position is particularly space-saving, since a drift path is provided between the two special magnetic condenser lenses 303.1 and 303.2. The configuration of the double-sealing and column separation module 710 within this drift path saves installation space or column height.

[0178] In Figure 5 In the exemplary embodiment shown in B, the double-sealing and column separation module 710 is configured between the condenser lens system 303 and the multi-beam generator 305. In the shown example, the condenser lens system contains two condenser lenses 303.1 and 303.2; however, it can also contain more than two condenser lenses in nature. The advantage of the depicted exemplary embodiment is that the replacement module 701 can be preconfigured or pre-adjusted to a greater extent. This is particularly relevant for the complete pre-adjustment of the particle source 301 and the entire condenser lens system 303.

[0179] According to Figure 5 In the exemplary embodiment shown in C, the double-sealing and column separation module 710 is configured further down the illumination column 700. Specifically, the double-sealing and column separation module 710 is configured between the first field lens 308 and the second field lens 103 of the field lens system. In this embodiment variant, the replacement module 701 can even be slightly larger than in the examples according to Figure 5 A and Figure 5 B. This allows for a greater pre-qualification or pre-adjustment of the more constituent parts of the replacement module 701 before the replacement of the particle source 301. Specifically, the optimal pre-setting of the charged particles on the multi-beam generator 305 can even be done before the replacement of the particle source 301. This in turn saves time during the actual replacement of the particle source 301. However, this is at the expense of greater material and manufacturing effort. However, after the replacement of the particle source 301, one or more constituent parts of the replacement module 701 can be reused or refurbished for the new replacement module 701.

[0180] In Figure 5In the depicted example, the following relation applies to the total height h of the dual sealing and column separation module 710 measured along the optical axis of the multi-beam particle microscope 1 in the installed state: h < 8.0 cm, preferably h < 7.0 cm or h < 6.0 cm. In this case, the dual sealing and column separation module 710 has a minimum height h due to the design, for example about 5.0 cm, to ensure the necessary stability and sealing of the dual sealing and column separation module 710.

[0181] Furthermore, in all the embodiment variants shown, the particularly sensitive micro-optical components of the multi-beam generator 305 are well protected during the replacement of the particle source 301 : in accordance with Figure 5 Figure 5 A and Figure 5 B, the lower sealing element 715 is closed before the replacement of the particle source 301 or the removal of the replacement module 701. Thus, the multi-beam generator 305 or the micro-optical components located therein remain in a protected vacuum during the replacement. However, in accordance with the embodiment variant Figure 5 C, there is no contamination problem of the micro-optical components or the multi-beam particle generator 305 in this way, since it is a component of the replacement module 701.

[0182] Figure 6 The replacement of the particle source 301 is schematically illustrated. In this case, the particle source 301 is configured in the replacement module 701.1. The other components of the illumination column 700 can likewise be configured in the replacement module 701.1; in this regard, Figure 6 only the replacement solution is shown, without the specific configuration of the replacement module 701.1, for example as shown in Figure 5 A to Figure 5 C. In this case, the illumination column 700 is separated by the dual sealing and column separation module 710 into the replacement module 701.1 and the remaining illumination column 702. In Figure 6 A, it has been spatially separated into its two partial modules, in particular the first partial module 711.1 and the second partial module 712. In this case, Figure 6 The arrows in Figure 6 A should illustrate the spatial separation of the two partial modules 711.1 and 712. Each of the two sealing elements 714.1 and 715 is closed itself during the separation procedure, so that a high vacuum can be maintained in both the replacement module 701.1 and the remaining column 702. The vacuum in the intermediate region 716 within the dual sealing and column separation module 710 is destroyed before the separation, in particular by the inlet as already explained in the context of the preceding figures. In the depicted example, the part of the intermediate region or the adapter means containing the inlet and the supply line 718 remains configured on the remaining column 702, or on the second partial module 712, or in any case has an integrated embodiment with the latter.

[0183] Once the replacement module 701.1 has been removed from the remaining column 702, the replacement particle source 301.2 can now be taken from the housing 720 and placed on the remaining column 702 to replace the original module 701.1. Figure 6 B illustrates this procedure:

[0184] In the example shown, the housing 720 contains three storage spaces for three replacement modules 701.2, 701.3 and 701.4. Each of these 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 is pre-certified and / or pre-adjusted. Additionally, the replacement modules 701.2, 701.3 and 701.4 have been evacuated and stored in or on the housing 720 together with the open sealing elements 711, 712. In this process, the interior 721 of the housing 720 is evacuated by the vacuum pump 719.

[0185] Now, for example, before the replacement module 701.2 is taken from the housing, the two sealing elements 714.2 and 715.2 are closed. The vacuum in the intermediate region between the two sealing elements 714.2, 715.2 is destroyed, so that the replacement module 701.2 can now be taken from the housing 720 without any problems. The replacement module 701.2 is then transported to the remaining column 702 and can be placed on the remaining column 702. Figure 6 The arrows in B illustrate these movements in sequence. In this case, the first part module 711.2 of the second replacement module 701.2 has the same structure as the first part module 711.1 of the old replacement module 701.1. Therefore, the first part module 711.2 is assembled exactly on the second part module 712, so that a new double-sealed and column-separable module 710 can be assembled from it. After the replacement module 701.2 has been arranged on the remaining column 702, first the intermediate region 716 between the first sealing element 714.2 and the second sealing element 715 is evacuated. The intermediate region 716 can additionally be baked, for example by means of heating elements arranged in the double-sealed and column-separable module 710 (not shown in the figure). After this relatively short evacuation process and optional baking of the double-sealed and column-separable module 710, the sealing elements 714.2 and 715 can then be opened again.

[0186] In an ideal case, the configuration of the second replacement module 701.2 is balanced in respect to the remaining part or remaining column 702 of the multi-beam particle microscope 1. In this case, no further adjustment of the replacement module 701.2 in respect to the remaining column 702 is necessary. Additionally or alternatively, the adjustment of the second replacement module 701.2 can be performed by adjustment members. Additionally or alternatively, the second replacement module 701.2 can be adjusted by electric and / or magnetic deflection fields deflecting the charged particles and / or the charged first individual particle beams. According to these adjustment steps, the multi-beam particle microscope 1 can be operated with the new particle source 301.2.

[0187] In principle, the described replacement of the particle source 301 in the replacement module 701 can be repeated, exactly until all replacement modules 701 stored in the accommodation 720 have been installed. Furthermore, essentially, the accommodation 720 can be filled with new, pre-characterized and pre-adjusted replacement modules 701 emptying the storage space in the accommodation 720. In this way, replacement modules with new particle sources 301 are always available. Furthermore, essentially, replacement modules 701 for a plurality of multi-beam particle microscopes 1 can be stored in the accommodation 720.

[0188] Figure 7 Details of a multi-beam particle microscope 1 with replaceable particle sources are schematically shown. The illumination column 700 of the multi-beam particle microscope 1 comprises a first vacuum region 730 with a first particle source 301.1 configured in an operating position 731 in the illumination column. Thus, the first particle source 301.1 is positioned and configured such that it can emit charged particles for operation of the multi-beam particle microscope 1. In this embodiment variant of the present application, a plurality of replacement particle sources 301.2, 301.3 and 301.4 have also been pre-characterized and / or pre-adjusted. They are located in a storage unit 741 comprising a plurality of storage positions 742.1, 742.2, 742.3 and 742.4. In this case, the storage unit 741 is configured in a vacuum region 740. In this vacuum region 740, a high vacuum or an ultra-high vacuum can be provided by a vacuum pump 719.

[0189] Furthermore, a transport mechanism can be provided for vacuum transport of the replacement particle source 301.2, 301.3, 301.4 from a storage unit 741 in the second vacuum region 740 into an operating position 731 in the first vacuum region 730. Thus, a pre-configured replacement particle source 301.2, 301.3, 301.4 which is structurally identical to the first particle source 301.1 can enter the operating position 731 if necessary and thus can act as an active particle source 301. The transport mechanism can have a single component or a multi-component design and can be realized in technically different 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 within the second vacuum region 740 by movement of the transport rod 744. Thus, it is envisaged that the particle source 301 for replacement can be moved to the necessary z-position for transport in the narrower sense. For example, the transport rod 743 which can be displaced in the x-direction in the example shown can be used to transport the replacement particle source from the second vacuum region 740 into the first vacuum region 730. A further component of the transport mechanism can be a platform of the illumination column 700 which can be displaced in the z-direction. Thus, the operating position 731 of the active particle source 301.1 can be displaced in the z-direction and, if necessary, the replacement particle source is transferred to a transport or switching position. 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 ultrahigh vacuum slide 745 which is opened during transport of the particle source 301 is arranged between the two regions 730, 740 or chambers 730, 740. However, it is also possible to form the two vacuum regions 730, 740 as a joint vacuum chamber and to not provide a gas lock and slide between the two regions 730, 740. In the preferred case, the transport mechanism is also configured for vacuum transport of the first particle source 301.1 from the operating position 731 in the first vacuum region 730 into the storage unit 741 in the second vacuum region 740. For example, the same transport rod 743 can be used to place the replacement particle source 301 in the illumination column 700 and to remove the replacement particle source therefrom again.

[0190] In this embodiment variant of the application it is important that the pre-identified replacement particle source 301.2, 301.3, 301.4 is configured in a vacuum region which is directly or indirectly connected to the vacuum region 730 of the illumination column. Thus, there is no separate accommodation provided with a replacement particle source or a complete replacement module. Thus, the replacement unit can be smaller than in the case of the replacement module 701 described according to the embodiment variant of the application. Figure 2 to Figure 6 It can also be said that the replacement particle source 301 is integrated in the multi-beam particle microscope 1.

[0191] In Figure 7In the exemplary embodiment shown, the storage unit 741 has a plurality of storage positions 742.1, 742.2, 742.3 and 742.4 configured according to a physical linear layout. In this case, the storage positions 742 are configured in a stack in the z-direction and are entered into the transport position by linear displacement, i.e. in the z-direction. An alternative physical linear layout can also be designed such that the storage positions 742 are configured in succession in the x-direction. In this way, the replacement particle source 301 can be entered into the operating position 731 in succession and moved out of the illumination column 700 again on the other side.

[0192] Figure 8 A further embodiment variant of the application is schematically shown which comprises a multi-beam particle microscope with a replaceable particle source 301. In this embodiment variant, the replacement particle source 301 is also configured in a storage unit 741. This storage unit 741 is located in the vacuum region 740. In the example shown, the vacuum region 740 is formed integrally with the vacuum region 730, wherein the particle source 301.1 is configured in the operating position 731. In this case, Figure 8 A schematic plan view of the active particle source 301.1 and the replacement particle sources 301.2 to 301.5 in the storage unit 741 is shown.

[0193] Figure 8 The embodiment shown differs from the embodiment shown in Figure 7 The embodiment shown differs from the embodiment shown in Figure 8 In the embodiment variant shown in Fig. 7, the storage unit 741 has a plurality of storage positions 742.1 to 742.5 configured according to a physical star-shaped layout. In the example shown, the storage positions 742.1 to 742.5 are located on a ring. In this case, the replacement particle sources 301.1 to 301.5 can each be entered into the operating position 731 by means of a movement directed towards the centre of the circle, i.e. a star-shaped movement. This movement is a movement along the radius r; it is indicated schematically by the double-headed arrow in Fig. 7. Furthermore, by way of example, the first particle source 301.1 has been entered into the operating position 731 from its storage position 742.1 by means of a radial movement using the transport lever 743.1. Figure 8

[0194] ​Again, in this embodiment variant of the application, the replacement of the particle sources 301 from the storage unit 741 in the operating position 731 is carried out completely in vacuum or high vacuum. There is no need to first break the vacuum and then reestablish the vacuum. Thus, the replacement of the particle sources 301 can be achieved more quickly and contamination of the vacuum regions 730, 740 is generally avoided. In fact, only when all the replacement particle sources 301.2 to 301.5 have been used or consumed, it is necessary to open the multi-beam particle microscope 1 and, essentially, to break the vacuum for this purpose. Then, in this case, the multi-beam particle microscope 1 can be equipped with a plurality of particle sources 301 at once, each of which has been pre-characterized and / or pre-adjusted. Overall, the time required for the replacement of the particle sources 301 is thus also significantly reduced in this way.

[0195] Figure 9 A further exemplary embodiment of a multi-beam particle microscope with replaceable particle sources 301 is shown. In this case, Figure 9 A shows a schematic lateral cross-sectional view, Figure 9 B shows a schematic plan view. Again, this embodiment variant of the application differs from the exemplary embodiments described in Figure 7 and Figure 8 in the layout: a storage unit 741 is provided with a plurality of storage positions 742.2 to 742.6 for the replacement particle sources 301.2 to 301.6, which are configured according to a physical ring layout. The operating position 731 of the active particle source 301.1 is also located on this ring or ring band. In the example shown, this physical ring layout is implemented by a carousel 746. This physical ring layout can also be referred to as a tower layout. In this case, the carousel 746 comprises rods or links 750, around which the carousel 746 can be rotated about a rotation center 747. This allows the replacement particle sources 301.2 to 301.6 to be rotated into the operating position 731.

[0196] A contact unit 748 with electrical contacts 749.1 to 749.3 is also exemplified in this embodiment of the application. This contact unit 748 is used to electrically contact the respective active particle source 301 in the operating position 731. For example, this can relate to spring-loaded contacts for establishing an electrical connection (cf. Figure 9 B). In an alternative, the contact unit 748 can be moved in the Z direction by a Z stage, so that the contact unit 748 can be connected to the corresponding active particle source 301 like a connector. It should be noted in this context that these contacts 749.1, 749.2 and 749.3 are contacts that can be used for high-voltage purposes. For example, the tip cathode, the extraction aperture and the anode aperture of the particle source 301 can be contacted by the contacts 749.1, 749.2 and 749.3.

[0197] In Figure 7 to Figure 9In all of the shown embodiment variants, a selective settable adjustment unit is provided for fine positioning of the corresponding active particle source 301 in the operating position 731. In this context, the adjustment unit can again have a single component or a multi-component design. For example, it can be implemented by means of a 3D stage and / or by means of a piezoelectric element. Other embodiments are also possible here.

[0198] In general, in the embodiment variants of the application depicted in Figure 7 to Figure 9 It is also applicable in the embodiment variants of the application depicted in

[0199] Figure 10 A part of a multi-beam particle microscope 1 is schematically shown which has replaceable particle sources 301, wherein the replacement is carried out by means of a switch. According to this embodiment of the application, a plurality of structurally identical particle sources 301.1 to 301.4 have a spatially fixed configuration. As a result, it is not necessary to transport or move the particle sources 301 from a storage position to an operating position. The transport mechanism has been replaced by a switching member which is configured to switch between the particle sources 301.1 to 301.4, so that in each case only exactly one of the particle sources 301.1 to 301.4 is the active particle source which emits charged particles 309 at any time. In this case, the controller 10 of the multi-beam particle microscope 1 is configured to control the switching member to carry out the switching. This is accompanied by a control of the particle sources 301.1 to 301.4, so that only exactly one of the particle sources 301 is the active particle source 301.1 at any time.

[0200] In order to enable a precise coupling of the emitted charged particles 309 from each of the particle sources 301.1 to 301.4 or from each operating position into the illumination column 700 of the multi-beam particle microscope 1, this embodiment of the application provides an electric and / or magnetic deflection member which is configured to deflect the charged particles 309 emitted by the respective active particle source 301.1 onto the optical axis 350 of the multi-beam particle microscope 1. In this case, the controller 10 of the multi-beam particle microscope 1 is configured to also control the deflection member.

[0201] In the exemplary embodiment shown in Figure 10 In the exemplary embodiment shown in Figure 10In the plan view of A, the optical axis is directed to the drawing plane; the optical axis 350 extends in the z-direction. In the example shown, the particle sources 301.1 and 301.3 are in addition configured as a pair and opposite to each other. The corresponding statement applies to the particle sources 301.2 and 301.4. Of course, in this case all particle sources 301.1 to 301.4 are configured in a vacuum or high vacuum.

[0202] In Figure 10 In the exemplary embodiment shown, the deflection means comprises two pairs of Helmholtz coils 344, 345, thus in total four coils 344.1, 344.2, 345.1 and 345.2, wherein only one pair of Helmholtz coils pair 344, 345 is in active state at any time in each case. In this case, the coils 344.1, 344.2, 345.1, 345.2 are configured between one of the particle sources 301.1 to 301.4 and the optical axis 350 of the multi-beam particle microscope 1 or an imaginary extension of the optical axis 350, respectively. In this case, the axes of the two Helmholtz coil pairs 344, 345 are configured orthogonal to the optical axis 350 of the multi-beam particle microscope 1, such that the magnetic field B generated by the Helmholtz coil pair 344, 345 in each case is oriented orthogonal to the optical axis 350 of the multi-beam particle microscope 1. In this case, the controller 10 is configured to control the Helmholtz coil pairs 344, 345 in a manner such that the charged particles 309 emitted by the respective active particle source 301 are deflected in the direction of the optical axis 350 of the multi-beam particle microscope 1.

[0203] In accordance with Figure 10 In the example of A, the particle source 301.1 as active particle source emits charged particles 309. The charged particles pass through the opening in the coil 344.1 of the Helmholtz coil pair 344, which in this case is not activated. In contrast, the Helmholtz coil pair 345 with the two Helmholtz coils 345.1 and 345.2 is activated, so that the emitted charged particles 309 experience a magnetic field B orthogonal to their emission direction and also orthogonal to the optical axis 350 of the multi-beam particle microscope 1. The charged particles 309 are deflected on a circular trajectory. In the example shown, the charged particles 309 describe a quarter circular arc. This is shown in Figure 10 B, which shows a side view through the particle source region or head of the multi-beam particle microscope 1. After a deflection of 90°, the charged particles 309 exit the magnetic field of the Helmholtz coil pair 345 in the example shown and pass through the diaphragm 346 with the aperture 347. At this point the orientation of the charged particles 309 is parallel to the optical axis 350 or z-direction. Next, the charged particles 309 reach the condenser lens system or collimator lens system 303 (not shown in this view) and are focused on the sample 305. Figure 10not shown).

[0204] For example, if now a switch between particle source 301.1 and particle source 301.2 exists, then particle source 301.2 becomes the active particle source and particle source 301.1 becomes inactive. Again, Helmholtz coil pair 345 is deactivated and Helmholtz coil pair 344 is activated. For the replacement particle sources 301.3 and 301.4 a corresponding procedure can be implemented as well.

[0205] Figure 11 A further embodiment variant of the present application is shown, wherein the replacement of the particle sources 301 is not implemented by a mechanical transfer, but by a switch as well. Figure 11 The essential difference of the exemplary embodiment shown in Fig. 11A and 1 IB is the design of the deflection means: In the embodiment variant according to Figure 10 An electric deflection means is used in the embodiment variant according to Figure 11 Fig. 11A. Again, the configuration of the particle sources 301.1 to 301.4 differs slightly from the configuration according to Figure 10 Fig. 10A: This is because, the pair-wise opposite particle sources 301.1 to 301.4 are configured with an inclination angle a with respect to the optical axis 350 of the multi-beam particle microscope 1. Figure 11 B best shown; wherein a side view is schematically depicted: The pair-wise opposite particle sources 301.1 to 301.3 are inclined by about 45° with respect to the optical axis 350 of the multi-beam particle microscope 1. However, the angle a can also be slightly larger or slightly smaller, e.g. 40° < a < 50°. In the example shown, the deflection means comprises four deflection electrodes, which correspond to the four anodes 343.1 to 343.4 of the four particle sources 301.1 to 301.4 in the example shown. However, the four deflection electrodes can also be separately provided, i.e. separate 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 control the deflection electrodes of the particle source 301 opposite to the active particle source 301 in each case using a deflection potential, such that the charged particles emitted by the respective active particle source 301 are deflected in the direction of the optical axis 350 of the multi-beam particle microscope 1. In the example according to Figure 11 Fig. 11A, the particle source 301.1 is active. The particle source 301.3 with the same deflection electrode 343.3 as the anode of the particle source 301.3 in the example shown is opposite to this active particle source. The function of this deflection electrode as deflection electrode 343.3 is only obtained by the respective control of the particle source 301.3, or in the exemplary case depicted, only by the respective control of the anode 343.3 of the particle source 301.3. In Figure 11 A and 1 IB, the deflection potential is indicated by a negative sign in front of the anode 343.3 in each case. Otherwise, Figure 11 The embodiment variant shown in Fig. 11A and 1 IB differs from the embodiment variant according to Figure 10The same phenomenon is shown: the charged particle 309 deflected onto the optical axis 350 passes through the aperture 347 through the aperture 346 and continues along its path to the condenser 303.

[0206] Figure 12 The illustration shows another embodiment variant of the multi-beam particle microscope 1 with a replaceable particle source 301, wherein the replacement is again implemented by switching. Figure 12 The exemplary embodiments shown are in accordance with Figure 10 The difference in the exemplary embodiment shown lies in the position of the condenser lens system 303: in accordance with Figure 12 In a variant embodiment, the condenser lens system 303 is mounted higher, prior to the charged particles 309 being connected to the (shared) optical axis 350 of the multi-beam particle microscope 1. The charged particles 309 pass through the first magnetic lens 303.1a of the condenser lens system before entering the magnetic field of the deflection members or the Helmholtz coil pair 345. The second magnetic condenser lens 303.2 is positioned downstream of the deflection members 344, 345 and centered on the optical axis 350. Therefore, in this embodiment of the invention, each particle source 301.1 is further equipped with magnetic condenser lenses 303.1a to 303.1d specifically assigned to that particle source (i.e., four additional magnetic lenses). Figure 12 The embodiments of the present invention shown are compared to Figure 10 The illustrated variant saves even more space.

[0207] Figure 13 The diagram schematically illustrates a multi-beam particle source 301 and the positional dependence of its current intensity. In the illustrated example, the particle source 301 is constructed as follows: it includes a cathode tip 340 surrounded by a suppression electrode 341 in the form of a transverse cylindrical surface, the suppression electrode 341 being used to suppress the transverse emergence of electrons from the cathode tip 340. For example, the cathode tip 340 may be a thermal field emitter operating with a heating current of several amperes. A voltage of several hundred volts relative to the cathode tip 340 is applied to the suppression electrode 341. A voltage of several thousand volts relative to the cathode tip 340 is applied to an extraction electrode 342 disposed at a distance from the cathode tip 340. An anode 343 is disposed below the extraction electrode 342, or approximately 1 cm below the cathode tip 340. The accelerating potential between the tip 340 and the anode 343 is tens of thousands of volts, for example, 25 kV, 30 kV, or 35 kV. A condenser lens system with magnetic focusing lenses 303.1 and 303.2 is disposed in the particle beam path downstream of the particle source 301. This causes the collimated particle beam 311 to be shaped, and the collimated particle beam is incident on the first plate (filter plate) of the multi-beam generator 305 (only on the first plate). Figure 13 (As shown in the cross-section of A).

[0208] In the exemplary embodiment shown, the anode 343 is designed as an anode diaphragm having a central anode aperture 348. A portion of the beam cone 310 emitted by the tip 340 is cut off at the aperture 348.

[0209] Figure 13 B depicts the current strength of the emitted charged particles in a cross-sectional view through the optical axis 350: Herein, the curve 351 shows the current strength of the new particle source 301, while the curve 352 shows the curve of the old particle source 301, which is thus replaced. There is a plateau region 353 in the case of the new particle source 301 or curve 351. The current strength is very uniform in this region, and this plateau region 353 can thus be well used for producing a plurality of individual particle beams having the same beam current density. To this end, the plateau region 353 ideally corresponds to the opening region 348 of the anode diaphragm 343. In the example shown, a tooth 354 of the curve 351 is cut off by the anode diaphragm 343. Now, if the cathode tip 340 is not in the optimum position, i.e. not exactly on the optical axis 350, then the curve 351 is also displaced relative to the optical axis 350. Thus, if the anode diaphragm 343 is provided with a particular sensor system, it is possible to determine by means of a spatially resolved measurement of the current strength whether the cathode tip 340 is precisely aligned relative to the optical axis 350 and / or precisely aligned relative to the center of the anode opening 348. Then, based on such a current pattern measurement, the corresponding alignment of the cathode tip 340 can be readjusted or fine-tuned. For example, the cathode tip 340 can be displaced in all spatial directions relative to the extraction electrode 342 and / or the anode 343. Additionally or alternatively, a rotation about these axes / spatial directions is possible, for example by means of a six-legged spider mechanism.

[0210] Additionally or alternatively, the current strength or current pattern in the region of the particle source 301 can also be monitored. The remaining useful life of the particle source 301 can then be predicted based on the current pattern, and in particular the replacement of the active particle source 301 can be initiated. In principle, it is known that the emission characteristics of the particle source 301 change over the service life of the particle source 301 and how they typically change. One example for this purpose is Figure 13 the curve 352 in B: The tooth 354 no longer exists in the current strength curve 352 of the old particle source 301. There is also no longer a real plateau. Additionally, there is also a change in the absolute current strength, wherein the current strength typically increases strongly again shortly before the particle source 301 fails. Based on this knowledge, the remaining useful life of the particle source 301 can be predicted, and in particular the replacement of the particle source 301 can also be initiated in time.

[0211] Figure 14The current pattern acquisition at the anode diaphragm 343 is schematically shown, which can be used for fine-tuning the particle source 301. In addition or alternatively, the current pattern acquisition can also be used to predict the service life of the currently active particle source 301 and / or to initiate the replacement of the active particle source 301. In principle, the current pattern can be obtained in different ways in the area of the particle source 301. For example, the current pattern acquisition at the anode diaphragm 343 is described. However, the current pattern acquisition can essentially be carried out in a completely analogous manner on the extraction diaphragm 342 or even on a further, separately arranged diaphragm. Figure 14 Only the principle of this aspect is shown:

[0212] The anode diaphragm 343 comprises a central opening 348, through which some of the emitted particles 309 pass. In general, those particles have an effect on a flat region 353 of the current strength (see Figure 13 B). The emitted particles also impinge on the anode diaphragm 343 around the anode aperture 348. Now, with spatial or local resolution, the current strength or beam current density of these charged particles, which are intercepted by the diaphragm 343, can be determined. For this purpose, the anode diaphragm 343 according to Figure 14 A is subdivided into individual sectors S 11 to S xy . Individual beam current measurements can be carried out in each of these sectors S ij . In the simplest case, for this purpose a plurality of high-sensitivity current meters, for example picoammeters, are used. In this case, the individual sectors S ij are insulated from one another. The sectors S ij can be in the form of special-shaped sensor plates, the insulation between which is achieved in a concealed manner by means of a labyrinth, so that charging of the insulator by the charged particles between the sectors can thus be prevented. In an alternative, the individual sectors S ij can be designed as scintillators. Other embodiments for the current pattern acquisition are also possible.

[0213] Figure 14 B shows different geometric configurations of the sectors S ij for acquiring a spatially resolved current pattern. In the example shown, three concentric rings are provided, which are in turn subdivided into individual sectors S i . Each sector S i has an individual beam current measurement. For the sake of clarity, Figure 14 not all sectors are drawn, nor are all current measurement devices.

[0214] In addition or alternatively, the beam current can also be monitored in different ways in order to draw conclusions in this way about the remaining service life of the active particle source 301. In this connection, reference is again made to the previously already cited WO 2023 / 001402 A1.

[0215] Figure 15The diagram schematically shows a plan view of a metal covering element 760 that can be inserted into the beam path of a multi-beam particle microscope 1. The conductive covering element 760 includes a particle protector 770, narrowly defined as a covering element, and a region 770 that essentially extends as a beam tube. In the illustrated example, this region 770 is tubular and can be implemented via a circular through-hole 762 in the covering element 760. In the illustrated example, the covering element 760 includes a metal cantilever that can be displaced in the x-direction and is therefore orthogonal to the optical axis (which points to...). Figure 15 The displacement in the plane of the diagram (i.e., in the z-direction). Figure 15 In this context, this displaceability is indicated by a double-headed arrow. The cover element 760 is held and guided by element 765, thus allowing for precise displacement along the x-direction. The cover element 760 can be positioned above the multi-beam generator 305 relative to the particle beam path in a multi-beam particle microscope, so that the multi-beam generator 305 is covered by the cover element 760 in the inserted state. In this case, the particle guard 770 closes or covers the beam tube. The beam tube is open in the non-inserted state; charged particles pass through the through-holes in the cover element. The conductive cover element 760 can be implemented in different ways; in this respect, Figure 15 This explanation only illustrates the functional principle. For example, the cover element 760 may be designed as a metal slider or metal cantilever, or as a movable disk. During particle source 301 replacement, the cover through particle protection 770 provides additional protection for the multi-beam generator 305. During particle source 301 replacement, the conductive cover element serves to prevent contamination and to protect the electronic components mounted in the multi-beam generator 305 from scattered electrons and / or high-energy light radiation. Alternatively, a multi-beam particle microscope 1 with the aforementioned conductive cover element 760 may be provided, but without the double-sealed and column separation module 710 according to the invention.

[0216] Figure 16A lateral cross-section of an exemplary configuration of the cover element 760 is schematically shown. According to this exemplary embodiment, the cover element 760 comprises or is in the form of a metallic cantilever 761, which can be displaced orthogonally to the particle beam path between a first diaphragm position 768 and a second diaphragm position 769, in this case in the x-direction. For example, the two diaphragms 768, 769 can be formed by a body 764, which is fixedly connected in space to the housing 708, 709 of the multi-beam particle microscope 1. The cantilever 761 can be supported and guided by a linear bushing 765, for example. The metallic cantilever 761 has a through-hole 762, the diameter of which advantageously matches the beam tube diameter of the beam tube adjacent thereto. When the cover element is in the first diaphragm position 768, charged particles can pass through the cover element 760 unhindered through the through-hole 762. Furthermore, the cantilever 761 has a recess 763, in particular circular, the diameter of which likewise advantageously matches the beam tube diameter of the adjacent beam tube. If the cantilever 761 is in the second diaphragm position, charged particles incident during operation of the multi-beam particle microscope 1 onto the recess. Particles which can enter the lower region of the illumination column 700 are incident onto the recess when the housing 708, 709 is opened and / or the vacuum in the multi-beam particle microscope 1 is destroyed. In this way, additional particle protection is generated during replacement of the particle source 301. In addition to the protection function, this embodiment variant has the further advantage that it can be used for beam current measurement purposes, for monitoring purposes and / or for adjustment purposes: This is because, according to a further preferred embodiment of the application, a beam current meter is arranged in the, in particular circular, recess 763 and / or the circular recess 763 is connected to a beam current meter. This makes it possible to measure scattered electrons, for example. Alternatively or additionally, the direct beam current can also be measured during operation of the multi-beam particle microscope 1.

[0217] According to an embodiment variant, the metallic cantilever 760 has a predetermined thickness and extends transversely to the entire beam tube 703 or through the entire beam tube. In principle, this achieves a lengthening of the beam tube 703 and better protection of the multi-beam generator 305 with electronic devices and / or circuits located thereon, for example, from occurring x-ray radiation. In this embodiment variant, the beam current meter is also able to determine the beam current directly or indirectly. In the case of this embodiment variant, it is also possible in principle to record or monitor the beam current with spatial resolution. In this case, the spatial resolution can be implemented in a similar manner to the principles described in Figure 13 and Figure 14

[0218] The exemplary embodiments described are not to be interpreted to restrict the application, but merely serve to better understand the application. Furthermore, the exemplary embodiments described in the figures can also be combined with one another in whole or in part, as far as no technical contradictions arise therefrom.

[0219] List of reference signs​

[0220] 1 multi-beam particle microscope

[0221] 3 primary particle beam, first individual particle beam

[0222] 5 beam spot, impingement position

[0223] 7 object, sample, wafer

[0224] 9 secondary particle beam, second individual particle beam

[0225] 10 computer system, controller

[0226] 15 sample surface, wafer surface

[0227] 25 imaging point of the second individual particle beam

[0228] 101 object plane

[0229] 102 objective lens

[0230] 103 field lens

[0231] 105 axis

[0232] 200 detector system

[0233] 205 projection lens system

[0234] 206 projection lens

[0235] 207 multi-particle detector

[0236] 208 projection lens

[0237] 209 projection lens

[0238] 210 projection lens

[0239] 212 intersection point

[0240] 214 aperture filter, contrast diaphragm

[0241] 220 multi-aperture corrector, individual deflector array

[0242] 222 collective counter-deflection system

[0243] 300 beam generation device

[0244] 301 particle source

[0245] 303 collimation lens system

[0246] 305 multi-aperture configuration, multi-beam particle generator

[0247] 306 micro-optical assembly with multi-well plate

[0248] 307 field lens

[0249] 308 field lens

[0250] 309 particle beam

[0251] 310 outer beam cone

[0252] 311 collimated particle beam

[0253] 321 intermediate image plane

[0254] 323 focal point of the beam

[0255] 340 cathode tip

[0256] 342 extractor, extraction diaphragm

[0257] 343 anode, anode diaphragm

[0258] 344 Helmholtz coil pair

[0259] 345 Helmholtz coil pair

[0260] 346 diaphragm

[0261] 347 aperture

[0262] 348 aperture

[0263] 350 optical axis

[0264] 351 current density of the new particle source

[0265] 352 current density of the old particle source

[0266] 353 flat region

[0267] 354 tooth

[0268] 400 beam splitter, magnetic configuration

[0269] 500 scanning deflector

[0270] 503 voltage source

[0271] 600 displacement stage or positioning device

[0272] 700 illumination column

[0273] 701 head of the illumination column, replacement module

[0274] 702 remaining illumination column, remaining column

[0275] 703 beam tube

[0276] 704 first beam tube portion

[0277] 705 second beam tube portion

[0278] 706 sealing surface

[0279] 707 filling volume

[0280] 708 housing

[0281] 709 housing

[0282] 710 double sealing and cylinder separation module

[0283] 711 first part module

[0284] 712 second part module

[0285] 713 intermediate piece, adapter

[0286] 714 first sealing element

[0287] 715 second sealing element

[0288] 716 intermediate region

[0289] 717 inlet, borehole

[0290] 718 vacuum-sealed line

[0291] 719 vacuum pump

[0292] 720 receiving portion

[0293] 721 evacuation region within the receiving portion

[0294] 722 shielding element

[0295] 723 shielding element

[0296] 724 upper region

[0297] 725 lateral region

[0298] 726 seal

[0299] 727 seal

[0300] 728 line

[0301] 729 line

[0302] 730 first vacuum region

[0303] 731 operating position

[0304] 740 second vacuum region

[0305] 741 storage unit

[0306] 742 storage location

[0307] 743 transfer lever

[0308] 744 transfer lever

[0309] 745 ultrahigh vacuum slide

[0310] 746 turntable

[0311] 747 rotation center

[0312] 748 contact unit

[0313] 749 electrical contact

[0314] 750 lever

[0315] 760 cover element

[0316] 761 metal cantilever

[0317] 762 through-hole

[0318] 763 circular recess

[0319] 764 main body

[0320] 765 holder

[0321] 766 diaphragm bellows

[0322] 767 adjacent body

[0323] 768 first aperture

[0324] 769 second aperture

[0325] 770 particle protection

[0326] 771 beam tube extension

[0327] V1 volume

[0328] V2 volume

[0329] V3 volume

[0330] V4 volume

[0331] T separation plane

Claims

1. A multi-beam particle microscope with a replaceable particle source, comprising the following features: A particle source, configured to emit charged particles. A multi-beam generator configured to generate a first field from the charged particles, comprising a plurality of first individual charged particle beams. A first particle optical unit having a first particle beam path is configured to image a generated first individual particle beam onto a sample surface in the object plane such that the first individual particle beam is incident on the sample surface at an incident position, the incident position forming a second field. The detection system has multiple detection zones that form a third field; The second particle optical unit, having a second particle beam path, is configured to image a second individual particle beam emitted from the incident position in 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 and second separate particle beams pass; A beam splitter is disposed in the first particle beam path between the multi-beam generator and the objective lens, and in the second particle beam path between the objective lens and the detection system; Sample stage, used to hold and / or position samples during sample inspection; A controller configured to control the multi-beam particle microscope; A beam tube having at least two beam tube sections disposed between the particle source and the beam splitter, wherein the beam tube is evacuated during the operation of the multi-beam particle microscope, and wherein the charged particles or the charged individual particle beams are guided within the beam tube during the operation of the multi-beam particle microscope. as well as A double-sealed and column-separation module is provided, which is sealed between the two beam tube sections during operation of the multi-beam particle microscope, through which the charged particles or the first individual particle beam pass, and which is spatially separable into a first part module and then into a second part module when the multi-beam particle microscope is not in operation. The first module includes a first sealing element configured to seal the adjacent beam tube portion on the particle source side when the first and second modules are spatially separated. The second module includes a second sealing element configured to seal the adjacent beam splitter section on the beam splitter side when the first and second modules are spatially separated. The dual-seal and column separation module includes an inlet in the intermediate region between the first sealing element and the second sealing element, which allows the intermediate region to be evacuated for the operation of the multi-beam particle microscope, and to break the vacuum in the intermediate region for the purpose of separating the first part module and the second part module.

2. The multibeam particle microscope as described in claim 1, further comprising: The replacement module includes the first part of the double-sealed and column separation module and components of the multi-beam particle microscope, the components being disposed above the double-sealed and column separation module relative to the particle beam path, including the particle source. The replacement module is configured to be replaced entirely within the multi-beam particle microscope.

3. The multi-beam particle microscope as described in any of the preceding claims further comprises: A condenser lens system is configured in the particle beam path downstream of the particle source and upstream of the multi-beam generator, and the charged particles pass through the condenser lens system. The dual-seal and column separation module is configured between the condenser lens system and the multi-beam generator.

4. The multibeam particle microscope as described in any one of claims 1 and 2, further comprising: A condenser lens system is configured in the particle beam path downstream of the particle source and upstream of the multi-beam generator, and the charged particles pass through the condenser lens system. The condensing lens system includes a first special magnetic condensing lens and a second special magnetic condensing lens, and The double-sealed and column separation module is configured between the first condenser lens and the second condenser lens.

5. The multi-beam particle microscope as described in claim 1, further comprising: A field lens system is configured in the particle beam path downstream of the multi-beam generator and upstream of the beam splitter, and the first charged individual particle beam passes through the field lens system. The field lens system includes a first special magnetic field lens and a second special magnetic field lens, and The double-sealed and column separation module is configured between the first field lens and the second field lens.

6. The multi-beam particle microscope as described in any of the preceding claims, The dual-seal and column separation module is configured to achieve 10 -10 ultra-high vacuum of millibars; and / or The dual-seal and column separation module is configured to achieve less than or equal to 10 -9 Leakage rate in mbar / l / s.

7. The multi-beam particle microscope as described in any of the preceding claims, The dual-seal and column separation module contains or is composed of a conductive material, and the relative permeability μ of the conductive material... r The following are applications: µ r ≤ 1.

005.

8. The multi-beam particle microscope as described in any of the preceding claims, The first and / or second sealing elements of the dual-seal and column separation module include components from the following list: ultra-high vacuum slider, valve, and pendulum valve.

9. The multi-beam particle microscope as described in any of the preceding claims, The first sealing element and / or the second sealing element are configured to be manually, pneumatically, or electrically operated.

10. The multi-beam particle microscope as described in any of the preceding claims, The following applies to the total height h of the dual-seal and column separation module, measured along the optical axis of the multi-beam particle microscope in the installed state: h ≤ 8.0 cm, especially h ≤ 7.0 cm or h ≤ 6.0 cm.

11. The multi-beam particle microscope as described in any of the preceding claims, The double-seal and column separation module also includes a heating element configured within the double-seal and column separation module.

12. The multibeam particle microscope as described in any of the preceding claims, The dual-seal and column separation module also includes an adjustment element for adjusting the replacement module, wherein the adjustment element is disposed adjacent to or integrated into the first part module on the particle source side.

13. The multibeam particle microscope as described in any of the preceding claims, The particle source includes a cathode tip, an extraction aperture, and an anode aperture, which are arranged flush with each other, or should be arranged flush with each other. The extraction aperture includes an extraction galvanometer configured to record the current pattern around the extraction aperture with spatial resolution; and / or The anode aperture includes an anode galvanometer configured to record the current pattern around the anode aperture with spatial resolution.

14. The multi-beam particle microscope as described in claim 13, The device includes a cathode positioning adjustment mechanism to set the position of the cathode relative to the extraction aperture and / or relative to the anode aperture based on a recorded current pattern.

15. The multi-beam particle microscope as described in any of the preceding claims further comprises: A conductive covering element is disposed above the multi-beam generator relative to the particle beam path and can be inserted into the particle beam path such that the multi-beam generator is covered by the covering element in the inserted state.

16. The multi-beam particle microscope as described in claim 15, The covering element is designed as a metal cantilever or includes a metal cantilever that can shift between a first aperture position and a second aperture position orthogonal to the particle beam path. The metal cantilever has a through-hole, the diameter of which matches the diameter of the beam tube adjacent to the through-hole. During the first aperture positioning, the charged particles can pass through the through-hole unimpeded through the covering element. The metal cantilever has a particularly circular recess with a diameter that matches the diameter of the adjacent beam tube, and the charged particles are able to enter the recess at the second aperture positioning point.

17. The multi-beam particle microscope as described in claim 16, The beam galvanometer is disposed in a particularly circular recess and / or the circular recess is connected to the beam galvanometer.

18. A system comprising: A multi-beam particle microscope with a replacement module as described in any one of claims 2 to 17, At least one additional replacement module for the multibeam particle microscope; and The housing has at least one vacuum-sealed connector for at least one additional replacement module. The receiving portion is configured such that when the first sealing element of the additional replacement module is opened, the interior of the additional replacement module is stored in the receiving portion under high vacuum, especially under ultra-high vacuum.

19. A method for replacing a particle source in a multi-beam particle microscope as claimed in any one of claims 2 to 17, comprising the following steps: The first sealing element and the second sealing element of the double-seal and column separation module are closed; The vacuum in the double-seal and column separation module in the area between the first sealing element and the second sealing element is disrupted; The double-sealed and column separation module is spatially separated into the first part module and the second part module, thereby separating the first replacement module containing the first particle source from the remainder of the multi-beam particle microscope; The second replacement module containing the second particle source is disposed on the remainder of the multibeam particle microscope, thereby combining the second double seal and column separation module, wherein the second replacement module has been evacuated and wherein the first sealing element is sealed. The second double-seal and column separation module is evacuated in the area between the first sealing element and the second sealing element. After vacuuming, open the first sealing element of the second double seal and column separation module and the second sealing element of the second double seal and column separation module.

20. The method of claim 19, further comprising the following steps: Heating the first and / or the second double-sealed and column separation module.

21. The method of any one of claims 19 and 20, further comprising the following steps: Before configuring the second replacement module in the remainder of the multi-beam particle microscope, the second replacement module is pre-adjusted and / or technically pre-qualified.

22. The method of any one of claims 19 to 21, further comprising the following steps: The second replacement module, which is in a vacuum state, is stored in the receiving section.

23. The method of any one of claims 19 to 22, further comprising the following steps: The second replacement module is evenly distributed across the remaining portion of the multibeam particle microscope; and / or Adjust the second replacement module using the adjustment mechanism; and / or The second replacement module is adjusted by an electric and / or magnetic deflection field that deflects the charged particles and / or the first individual charged particle beam.

24. The method of any one of claims 19 to 23, further comprising the following steps: Monitoring the current pattern in the particle source region; and The components of the particle source are adjusted relative to each other based on this current pattern.

25. The method of any one of claims 19 to 24, further comprising the following steps: Monitor the current pattern in the particle source region; and Predict the remaining lifetime of the particle source, and in particular, initiate the replacement of the particle source based on the current mode in each case.

26. The method as described in any one of claims 19 to 25, The method is performed in whole or in part multiple times, and in particular, a third replacement module having a third particle source and / or an additional replacement module having another particle source are configured on the remainder of the multi-beam particle microscope.

27. A multi-beam particle microscope with a replaceable particle source, comprising the following features: A first vacuum region having a first particle source configured to emit charged particles; A multi-beam generator configured to generate a first field from the charged particles, comprising a plurality of first individual charged particle beams. A first particle optical unit having a first particle beam path is configured to image a generated first individual particle beam onto a sample surface in the object plane such that the first individual particle beam is incident on the sample surface at an incident position, the incident position forming a second field. The detection system has multiple detection zones that form a third field; The second particle optical unit, having a second particle beam path, is configured to image a second individual particle beam emitted from the incident position in 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 and second separate particle beams pass; A beam splitter is disposed in the first particle beam path between the multi-beam generator and the objective lens, and is disposed in the second particle beam path between the objective lens and the detection system; Sample stage, used to hold and / or position samples during sample inspection; A controller configured to control the multi-beam particle microscope; The second vacuum region has a storage unit containing at least one second particle source with the same structure as the first particle source as a replacement particle source. as well as A transmission mechanism for transferring the second particle source from the storage unit in the second vacuum region to an operating position in the first vacuum region.

28. The multibeam particle microscope as described in claim 27, The transmission mechanism is further configured to transfer the first particle source from the operating position in the first vacuum region to the storage unit in the second vacuum region.

29. The multibeam particle microscope as described in claim 27 or 28, The first vacuum region and the second vacuum region are formed as separate vacuum cavities; or The first vacuum region and the second vacuum region are configured within the same vacuum chamber.

30. The multibeam particle microscope as described in any one of claims 27 to 29, The storage unit has multiple storage locations for the replacement particle source, which are configured according to a linear layout of the entity.

31. The multibeam particle microscope as described in any one of claims 27 to 29, The storage unit has multiple storage locations for the replacement particle source, which are configured according to a physical star-shaped layout.

32. The multibeam particle microscope as described in any one of claims 27 to 29, The storage unit has multiple storage locations for the replacement particle source, which are configured according to a solid ring layout.

33. The multibeam particle microscope according to any one of claims 27 to 32, further comprising: Contact unit for electrically contacting the corresponding active particle source in the operating position; and The adjustment unit is used to precisely position the corresponding active particle source in the operating position.

34. The multibeam particle microscope as described in any one of claims 27 to 33, Each replacement particle source includes a tip cathode, an extraction electrode, and an anode, which have been tuned and / or technically pre-qualified relative to each other.

35. A multi-beam particle microscope with a replaceable particle source, comprising the following features: Multiple identical particle sources are fixedly arranged in space, each configured to emit charged particles. A switching component configured to switch between the particle sources such that at any given time, in each case, only one of the particle sources is an active particle source that emits charged particles. An electric and / or magnetic deflection component configured to deflect charged particles emitted by the corresponding active particle source onto the optical axis of the multi-beam particle microscope; A multi-beam generator configured to generate a first field of a plurality of first individual charged particle beams from the charged particles of a particle source; A first particle optical unit having a first particle beam path is configured to image a generated first individual particle beam onto a sample surface in the object plane such that the first individual particle beam is incident on the sample surface at an incident position, the incident position forming a second field. The detection system has multiple detection zones that form a third field; The second particle optical unit, having a second particle beam path, is configured to image a second individual particle beam emitted from the incident position in 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 and second separate particle beams pass; A beam splitter is disposed in the first particle beam path between the multi-beam generator and the objective lens, and is disposed in the second particle beam path between the objective lens and the detection system; Sample stage, used to hold and / or position samples during sample inspection; A controller configured to control the particle source, the switching component, and the deflection component.

36. The multi-beam particle microscope as described in claim 35, The multi-beam particle microscope includes exactly four particle sources, which are arranged in pairs opposite to each other, and configured such that each of the particle sources can emit charged particles orthogonal to the optical axis of the multi-beam particle microscope; and The deflection mechanism comprises two pairs of Helmholtz coils, for a total of four coils, wherein only one pair of Helmholtz coils is activated at any given time in each case. One of the corresponding coils is positioned between one of the particle sources and an imaginary extension of the optical axis of the multi-beam particle microscope, and The axes of the Helmholtz coil pair are configured to be orthogonal to the optical axis of the multi-beam particle microscope, such that the magnetic fields generated by the Helmholtz coil pair are oriented orthogonal to the optical axis of the multi-beam particle microscope. The controller is configured to control the Helmholtz coil pair in such a way that charged particles emitted by the corresponding active particle source are deflected in the direction of the optical axis of the multi-beam particle microscope.

37. The multi-beam particle microscope as described in claim 35, The multi-beam particle microscope contains exactly four particle sources, which are arranged in pairs opposite each other and in each case are arranged with an angle of inclination α ≠ 0° relative to the optical axis of the multi-beam particle microscope, particularly 40° ≤ α ≤ 50°. The deflection member comprises four deflection electrodes, specifically the four anodes of the four particle sources, each deflection electrode being assigned to one particle source. The controller is configured to use a deflection potential to control the deflection electrode of the particle source opposite to the active particle source in each case, such that the charged particles emitted by the corresponding active particle source are deflected in the direction of the optical axis of the multi-beam particle microscope.

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