Element exchange in vacuum chamber of a multi-beam charged particle microscope

Abstract

For maintenance of a charged-particle microscope, a box (200) is attached in a vacuum-tight manner to a port (115) of a vacuum chamber (110) of the multi-beam charged-particle microscope, while the vacuum chamber (110) is in evacuated condition and the port (115) is sealed from outside by a lid part (162) of a first element (160) inserted into the vacuum chamber (110). The box (200) encloses a second element (161) for replacing the first element (160) and is provided with an opening (210) aligned with the port (115). The box (200) attached to the port (115) is evacuated. While the box (200) is in the evacuated condition, the first element (160) is pulled from the port (115) through the opening (210) into the box (200) and the second element (161) is pushed through the opening (210) from the box (200) into the port (115), thereby sealing the port (115) from outside by a lid part (162) of the second element (161). The box (200) is then vented and detached from the port (115).

Description

[0001] D E S C R I P T I O N

[0002] ELEMENT EXCHANGE IN VACUUM CHAMBER OF A MULTI-BEAM CHARGED

[0003] PARTICLE MICROSCOPE

[0004] TECHNICAL FIELD

[0005] The present disclosure relates to methods of exchange of an element in a vacuum chamber of a multi-beam charged particle beam microscope and corresponding devices and systems.

[0006] BACKGROUND

[0007] A scanning electron microscope (SEM) produces images by focusing a beam of electrons onto a sample surface. The electron beam including primary electrons is scanned across the sample, and the resulting signal, often generated by secondary electrons, is detected. A Multi-Beam Scanning Electron Microscope (MSEM) utilizes multiple electron beams to contemporaneously scan and image a sample, allowing for higher throughput and faster data acquisition compared to traditional single-beam SEMs.

[0008] In an MSEM, an aperture plate may be used to generate multiple electron beams from a single electron beam. Such aperture plate is inserted into the path of the electron beam and has multiple aperture holes through which the electron beam passes. It is also known to utilize a stack of multiple aperture plates to further condition the electron beams, e.g., by applying electric and / or magnetic fields in the vicinity of the aperture holes. Such single aperture plate or stacks of aperture plates are typically provided in the form of aperture plate module which is exchangeably inserted into the vacuum column of the MSEM. The aperture plate module may also include a lid part which, when the aperture plate module is installed, seals a flange of the vacuum column from the outside. The lid part may also be used when handling the aperture plate module, e.g., during installation or exchange. Further, the lid part may provide electrical connectivity to the aperture plate(s), e.g., by means of a connector on the outer side of the lid part.

[0009] As described in US 2020 / 0357600 A1 , a closed box may be used for handling and storing such multi-aperture plate modules. The box is attached to the vacuum enclosure of a multi-beam charged particle system, and an aperture plate module can then be moved from the vacuum enclosure into the box, and another aperture plate module can be moved from the box into the vacuum enclosure. The box ensures safe handling of the aperture plate modules and helps to prevent contamination during storage of the aperture plate modules. However, exchange of the aperture plate modules requires breaking the vacuum inside the vacuum enclosure of the multi-beam charged particle system, which means that exchanging the aperture plate modules, including recovery of the required vacuum conditions, is typically a rather time-consuming process, which may take up to several days. Due to exposure of the aperture plate module inside the box to ambient air, there is a risk of contamination of the aperture plate module while it is stored or transported within the box.

[0010] SUMMARY

[0011] Accordingly, a need exists for enhanced techniques which allow for efficiently exchanging an aperture plate module or similar element in the vacuum chamber of a multi-beam charged-particle beam microscope.

[0012] This need is met by the features of the independent claims. The features of the dependent claims define further embodiments.

[0013] One aspect of the present disclosure relates to a method for maintenance of a multibeam charged-particle microscope. The charged-particle microscope can be a MSEM, but the method could also be applied to other types of multi-beam charged- particle microscope, e.g., a multi-beam ion-beam microscopes. The multi-beam charged-particle-microscope is assumed to comprise a vacuum chamber. Typically, charged particle beams, e.g., electron beams, would be generated and / or guided within the vacuum chamber. Specifically, primary charged-particle beams would be guided to a sample to be investigated, secondary charged-particle beams, generated in response to interaction of the primary charged-particle beams with the sample, may be guided to a detector. Further, it is assumed that an exchangeable element is arranged in the vacuum chamber. Such exchangeable element may specifically be a multi-aperture plate module for conditioning multiple charged-particle beams of the multi-beam charged-particle microscope. However, other types of exchangeable elements could be considered as well. The exchangeable element comprises a lid part which, when the element is installed in the vacuum chamber, seals a port of the vacuum chamber from outside. For this purpose, the lid part may engage with a flange or other surface on the outside of the port.

[0014] According to the method, a box is attached in a vacuum-tight manner to the port of the vacuum chamber, while the vacuum chamber is in evacuated condition and the port is sealed from outside by the lid part of a first element inserted into the vacuum chamber. The box encloses a second element for replacing the first element. The box is provided with an opening aligned with the port. Then the box attached to the port is evacuated, thereby bringing the box to an evacuated condition. While the box is in the evacuated condition, the first element is pulled from the port through the opening into the box. Further, while the box still is in the evacuated condition, the second element is pushed through the opening from the box into the port, thereby sealing the port from outside by the lid part of the second element. The box attached to the port is then vented, and the box is detached from the port. By using the evacuated box, it can be achieved that the first element is replaced with the second element, without having to break vacuum inside the vacuum chamber.

[0015] In some embodiments, sealing of the box in the evacuated condition may be based on a vacuum seal between the port and the box. For example, the box may be attached in a vacuum-tight manner to a flange or other surface on the outside of the port. Evacuation of the box may then be achieved by pumping on a vacuum line attached to the port. A sealing pressure of the vacuum seal between the port and the box is at least in part based on a pressure difference between the vacuum chamber and the box. Handling and usage of the box may thereby be facilitated.

[0016] In some embodiments, the box may comprise a door for sealing the opening from inside the box while the box is not attached to the port. The method may then further comprise that the door is opened when the box is attached to the port and closed after the second element is inserted into the vacuum chamber and the port is sealed by the lid part of the second element. By means of the door, protection of the first or second element within the box may be enhanced. In some embodiments, the box may be vented with a high-purity gas and / or the box may be filled with a high purity gas before its attachment to the port. In this way, protection with respect to contamination from the outside atmosphere may be further improved. While the box is not attached to the port, a sealing pressure of the door against an inner sealing surface of the box may be based on pressure within the box, specifically a pressure difference between the interior of the box and the outside atmosphere. Opening of the door may be assisted by pressurizing the port, while the port is still sealed by the lid part of the first element. In this way, construction of the box and door may be implemented with low complexity.

[0017] In some embodiments, the box may comprise at least one manipulator for moving the first element and the second element. For example, such manipulator(s) may be used for pulling the first element from the port and / or for pushing the second element into the port. Further, such manipulator(s) may be used for moving the first element and / or the second element to or from a storage position within the box. The at least one manipulator may be configured for moving at least one of the first element and the second element in at least two different spatial directions. In this way, it can be facilitated that the first element is moved to a position within the box which does not obstruct pushing the second element into the port. In some embodiments, the at least one manipulator may comprise at least a first linear manipulator and a second linear manipulator. Alternatively or in addition, the box may comprise a flexible portion which enables displacing a first part of the box, which holds the first element or the second element, with respect to a second part of the box, which is attached to the port.

[0018] In some embodiments, a cover may be attached to the port after detaching the box from the port. Similarly, such cover could be attached to the port before the box is attached to the port. By means of the cover, a risk of contamination of the lid part of the first element or the lid part of the second element may be reduced. In some scenarios, the cover may be provided with a feed-through connector which mates with an electronics connector on the lid part of the element. Alternatively, the cover may be provided with an opening which provides access to an electronics connector on the lid part of the element.

[0019] A further aspect of the present disclosure relates to a box for maintenance of a multibeam charged-particle microscope. The multi-beam charged-particle microscope can be a MSEM, but the method could also be applied to other types of charged-particle microscope, e.g., a multi-beam ion-beam microscope. The multi-beam charged- particle-microscope is assumed to comprise a vacuum chamber. Further, it is assumed that an exchangeable element is arranged in the vacuum chamber. Such exchangeable element may specifically be a multi-aperture plate module for conditioning multiple charged-particle beams of the multi-beam charged-particle microscope. However, other types of exchangeable elements could be considered as well. The exchangeable element comprises a lid part which, when the element is installed in the vacuum chamber, seals a port of the vacuum chamber from outside. For this purpose, the lid part may engage with a flange or other surface on the outside of the port. The box may enclose a second element for replacing the first element. The box may be used for carrying out the above method for maintenance of a charged-particle microscope.

[0020] The box comprises an attachment portion for attaching the box in a vacuum-tight manner to a port of a vacuum chamber of the multi-beam charged-particle microscope, while the vacuum chamber is evacuated and the port is sealed from outside of the vacuum chamber by a lid part of a first element inserted into the vacuum chamber. Further, the box comprises an opening which aligns with the port when the box is attached. Further, the box comprises at least one manipulator for, while the box is attached to the port and in the evacuated condition, pulling the first element from the port through the opening into the box. Further, the at least one manipulator may be configured for pushing a second element enclosed in the box through the opening from the box into the port, thereby sealing the port from outside of the vacuum chamber by a lid part of the second element.

[0021] According to some embodiments, the box may comprise at least one gas port for evacuating and / or venting the box attached to the port.

[0022] According to some embodiments, the box comprises a door for sealing the opening from inside the box while the box is not attached to the port.

[0023] According to some embodiments, the at least one manipulator is configured for moving at least one of the first element and the second element in at least two different spatial directions. According to some embodiments, the at least one manipulator comprises at least a first linear manipulator and a second linear manipulator.

[0024] According to some embodiments, the box comprises a flexible portion which enables displacing a first part of the box, which holds the first element or the second element, with respect to a second part of the box, which is attached to the port.

[0025] A further aspect of the present disclosure relates to a system which comprises at least one box according to the above aspect and the multi-beam charged-particle microscope. Further, the system may comprise at least one of the above-mentioned first element and second element.

[0026] It is to be understood that the features mentioned above and those yet to be explained below may be used not only in the respective combinations indicated, but also in other combinations or in isolation without departing from the scope of the invention.

[0027] BRIEF DESCRIPTION OF THE DRAWINGS

[0028] FIG. 1 schematically illustrates a multi-beam charged particle microscope according to an embodiment.

[0029] FIG. 2 schematically illustrates an example of a transfer box according to an embodiment.

[0030] FIGs. 3A-3I schematically illustrate an example of a maintenance process according to an embodiment.

[0031] FIG. 4 schematically illustrates a further example of a transfer box according to an embodiment.

[0032] FIGs. 5A-5J schematically illustrate a further example of a maintenance process according to an embodiment.

[0033] FIGs. 6A, 6B, 7A, 7B, 8A, 8B, 9A, 9B, 10A, and 10B further illustrate examples of maintenance processes according to an embodiment.

[0034] FIGs. 11 A and 11 B schematically illustrates a further example of a transfer box according to an embodiment. FIG. 12 schematically illustrates a further example of a transfer box according to an embodiment.

[0035] FIGs. 13A and 13B schematically illustrate an example of connecting electronics to a multi-aperture plate module.

[0036] FIGs. 14A and 14B schematically illustrate an example of usage of a cover according to an embodiment.

[0037] FIGs. 15A and 15B schematically illustrate a further example of usage of a cover according to an embodiment.

[0038] FIGs. 16A and 16B schematically illustrate a further example of usage of a cover according to an embodiment.

[0039] FIG. 17 is schematically illustrates a further example of a transfer box according to an embodiment.

[0040] FIG. 18 shows a flowchart for schematically illustrating a method according to an embodiment.

[0041] DETAILED DESCRIPTION

[0042] In the following, embodiments of the invention will be described in detail with reference to the accompanying drawings. It is to be understood that the following description of embodiments is not to be taken in a limiting sense. The scope of the invention is not intended to be limited by the embodiments described hereinafter or by the drawings, which are taken to be illustrative only.

[0043] Various techniques disclosed herein relate to maintenance of a charged-particle microscope by exchanging an element arranged in a vacuum chamber of the multibeam charged-particle microscope. The charged-particle microscope may have the purpose of imaging a sample by scanning with multiple charged-particle beams. In the examples further detailed below, it is assumed that the charged-particle microscope is an MSEM which scans the sample by multiple electron beams. It is however noted that the illustrated concepts could also be applied to multi-beam microscopes using beams of other charged particles, e.g., ions. FIG. 1 schematically illustrates an MSEM 100 in accordance with the present disclosure. The MSEM 100 includes a vacuum chamber 110 which houses a beam source 120, a sample stage 130, and a detector 140. Operation of the MSEM 100 typically involves jointly scanning multiple primary electron beams 121 , derived from the beam source 120, across a sample arranged on the sample stage 130. Secondary electron beams 122 formed due to interaction of the primary electron beams 121 with the sample are detected by the detector 140. As further illustrated, the MSEM 100 may include various elements 150 for guiding and shaping the electron beams 121 , 122. Such elements 150 may for example be based on magnets and / or field electrodes.

[0044] The vacuum chamber 110 is provided with a number of ports 111 , 115. As illustrated, for the ports 111 may for example be used for connecting the vacuum chamber 110 to a vacuum pump system. In the illustrated example, the vacuum pump system is assumed to include vacuum pumps 181 , 182, 183 which may be used for evacuating the vacuum chamber 110. As further illustrated, the ports 111 may also be used for venting the vacuum chamber 110. Vacuum shutters 112 may be used for segmenting the vacuum chamber 110 into different compartments which can be evacuated or vented independently.

[0045] As further illustrated, a maintenance port 115 is provided for inserting an exchangeable element 160 into the vacuum chamber 110. In the illustrated example, the exchangeable element 160 is assumed to be a multi-aperture plate module which has a single aperture plate or stack of aperture plates with multiple aperture holes. The one or more aperture plates are inserted into the path of the electron beam coming from the beam source 120, and the electron beam passes through the aperture holes. In this way, a single electron beam coming from the beam source 120 may be transformed to multiple parallel electron beams. By applying electric and / or magnetic fields in the vicinity of the aperture holes, the electron beams may be further conditioned. Diameters of the aperture holes may be in the order of less than a micrometer, which makes the aperture-plate module susceptible to degradation by contamination. The risk of contamination significantly increases when the vacuum chamber 110 or the multi-aperture plate module is exposed to air.

[0046] As further illustrated, the element 160 has a lid part 162. When the element 160 is installed in the vacuum chamber 110, the lid part 162 seals the port 115 by engaging with a flange or other outer surface of the port 115. If the vacuum chamber 110 is under vacuum, the atmospheric pressure outside the vacuum chamber 110 provides at least a part of the sealing pressure of the lid part 162 against the outer surface of the port 115. In addition, the lid part 162 may be secured by screws and / or a clamp. Further, the lid part 162 may be used for engagement when handling the element 160, thereby avoiding a need for physical contact with the aperture plate(s) or other sensitive vacuum parts of the element 160. In this way, damages and / or contamination can be avoided.

[0047] In the example of FIG. 1 , a cover 116 is attached to the outside of the port 115 holding the element 160. The cover 116 may protect the port 115 and the lid part 162 of the element 160 from contamination during regular operation of the MSEM 100. Further details of such cover are explained below.

[0048] As further illustrated, the port 115 is connected to a vacuum pump 185 and to a vent line 184. The vacuum pump 185 may be used for evacuating an external portion of the port 115, which is arranged outside the lid part 162. The vent line 184 may in turn be used for venting the external portion of the port 115.

[0049] If during maintenance of the MSEM 100 the element 160 needs to be exchanged, the cover 116 can be removed from the port 115, the element 160 removed from the vacuum chamber 110, and then be replaced by another element. In accordance with the concepts illustrated herein, this can be achieved without breaking the vacuum in the vacuum chamber 110. For this purpose, the illustrated concepts involve usage of a transfer box which can be attached in a vacuum-tight manner to the port 115 and be evacuated before pulling the element 160 from the port 115. Details of such transfer box and of maintenance processes using the transfer box will be explained in the following.

[0050] FIG. 2 schematically illustrates an example of the transfer box 200. As can be seen, the transfer box 200 has an opening 210 which aligns with the port 115 of the vacuum chamber 110 when the transfer box 200 is attached to the port 115. For attaching the transfer box 200 to the port 115, the transfer box 200 may be provided with an attachment portion, e.g., a flange which mates with a corresponding flange on the port 115. Clamps and / or screws may be used for attaching the transfer box 200 to the port 115. Further, an O-ring or similar sealing element may be used for ensuring the vacuum seal between the attachment portion of the transfer box 200 and the port 115.

[0051] As further illustrated, the transfer box 200 otherwise forms a closed case which houses the further element 161 for replacement of the element 160 currently mounted inside the vacuum chamber 110. For this purpose, the transfer box 200 may be provided with a storage section where the further element 161 is placed. While the further element 161 is placed in the storage section, the further element 161 does not obstruct access to the opening 210 from inside the transfer box 200.

[0052] In the state as illustrated in Fig. 2, the transfer box 200 is not yet attached to the port 115, and the external portion of the port 115 is open to the outside atmosphere. Vacuum inside the vacuum chamber 110 is still ensured by the seal provided between the lid part 162 of the element 160 and the outer surface of the port 115. During normal operation of the MSEM 100 the lid part 162 may be secured by screws to the port 115. However, even if the screws are removed before attaching the transfer box 200, the vacuum inside the vacuum chamber 110 remains intact due to the pressure difference between the vacuum chamber 110 and the outside atmospheric pressure, which pushes the lid part 162 onto the outer surface of the port 115. It has been found that for typical dimensions configurations of the element 160 and lid part 162, the pressure difference, which is substantially 1 bar, is sufficient to maintain the vacuum seal.

[0053] As further illustrated, the transfer box 200 is provided with a set of linear manipulators 250, 260 which can be used to move the elements 160, 161 within the transfer box 200 and through the opening 210. In the illustrated example, the linear manipulators 250, 260 include a first linear manipulator 250 for moving the elements 160, 161 along a first spatial direction denoted by “A” and a second linear manipulator 250 for moving the elements along a second spatial direction denoted by “B”. The first direction extends along an axis of the port 115, and the second direction extends transversely to the first direction, in the illustrated example substantially perpendicular to the first direction. Each linear manipulator is provided with a grip mechanism that can engage the respective lid part 162 of the elements 160, 161 .

[0054] As regards the implementation of the manipulators 250, 260, various known types of manipulator or mechanical feedthrough may be used, which are compatible with the required level of vacuum inside the transfer box 200. For example, the manipulators 250, 260 could be based on driving movement inside the transfer box 200 from outside using elements like metallic membranes, spring bellows, special elastomer seals, magnetically coupled systems, or differentially pumped seals.

[0055] FIGs. 3A-3I illustrate different stages of the further process of replacing the element 160 with the further element 161 , using the transfer box 200.

[0056] In the stage illustrated by FIG. 3A, the transfer box 200 is still vented and attached in a vacuum-tight manner to the port 115.

[0057] In the stage illustrated by FIG. 3B, the first linear manipulator 250 is moved forward to engage with the lid part 162 of the element 160. The transfer box 200 is then evacuated, using the pump 185. As a result, the pressure difference between the vacuum chamber and the inside of the transfer box 200, which pushed the lid part 162 of the element 160 onto the outer surface of the port 115, is significantly reduced. Evacuation of the transfer box 200 is however not performed down to the same level of vacuum as inside the vacuum chamber 110, so that there is still some residual pressure difference remaining, which however allows for pulling the element 160 from the port 115, as further explained below. It is noted that the typical level of vacuum inside the vacuum chamber 110 corresponds to ultra-high vacuum (UHV), i.e. , lower than 10’8mbar, and that the level of evacuation inside the transfer box 200 could correspond to UHV as well, but could also be of lower degree, e.g., high-vacuum (HV) or of even lower degree.

[0058] In the stage illustrated by FIG. 3C, the first linear manipulator 250 is retracted to pull the element 160 from the port 115. To pull the element 160 from the port 115, the first linear manipulator 250 needs to exert sufficient pulling force on the element 160 so that the forces resulting from the residual pressure difference between the vacuum chamber 110 and the interior of the transfer box 200 are overcome.

[0059] In the stage illustrated by FIG. 3D, the element 160 has been pulled into a storage section within the transfer box 200, so that the opening 210 of the transfer box 200 is not obstructed by the element 160. The second linear manipulator 260 is then moved forward to engage with the lid part 162 of the further element 161 .

[0060] In the stage illustrated by FIG. 3E, the further element 161 has been pushed by the second linear manipulator 260 to a position where it is substantially aligned with the axis of the port 115 and in reach of the first linear manipulator 250. In the stage illustrated by FIG. 3F, the first linear manipulator 250 has been disengaged from the lid part 162 of the element 160 and moved forward to engage with the lid part 162 of the further element 161 , so that the further element can be pushed forward by the first linear manipulator 250.

[0061] In the stage illustrated by FIG. 3G, the further element 161 has been completely pushed into the port 115, so that the lid part 162 of the further element 161 forms a vacuum seal with the outer surface of the port 115. The transfer box 200 is then vented using the vent line 184. As a result, the pressure difference between the vacuum chamber 110 and the interior of the transfer box 200 increases, so that the lid part 162 of the further element 161 is further pushed onto the outer surface of the port 115, thereby further enhancing the vacuum seal of the lid part 162 with respect to the port 115.

[0062] In the stage illustrated by FIG. 3H, the first linear manipulator 250 has been disengaged from the lid part 162 of the element 161 and the transfer box 200 completely vented, so that the transfer box 200 is ready to be detached from the port 115. In the stage illustrated by FIG. 3I, the transfer box 200 has been detached from the port 115. The cover 116 may then be again placed on the port 115. Before placing the cover 116 on the port 115, screws for fixing the lid part 162 of the further element 161 on the port 115 may be installed.

[0063] As can be seen, using the processes of FIGs. 3A-3H, the elements 160, 161 may be exchanged in an efficient manner, without breaking the vacuum inside the vacuum chamber 110. A temporary increase of pressure in the vacuum chamber 110 due to opening the vacuum chamber 110 towards the interior of the transfer box 200 may be quickly compensated by continuous pumping on the vacuum chamber 110 during the exchange process, e.g., using one or more of the pumps 181 , 182, 183. It is noted that the temporary increase of the pressure in the vacuum chamber 110 during the illustrated process, which may reach up to a few orders of magnitude, was found to not affect the vacuum conditions in the vacuum chamber 110 in the long term. For example, UHV conditions may recover within a few hours following the end of the procedure of exchange of the element 160 against element 161 .

[0064] FIG. 4 schematically illustrates a further example of the transfer box 200’. Similar to the example of FIG. 2, the transfer box 200’ has an opening 210 which aligns with the port 115 of the vacuum chamber 110 when the transfer box 200’ is attached to the port 115. Further, the transfer box 200’ is provided with a door 220 which selectively closes the opening 210. When closed, the door 220 provides a gas seal with respect to an interior surface of the transfer box 200’. As illustrated by “C”, the door 220 may be opened in a flap-like manner. Any movements to close the door 220 and / or movements to open the door 220 may be accomplished with the aid of an actuating mechanism, e.g., based on magnetic elements which allow for moving the door 220 through the wall of the transfer box 200’. Further, a lock mechanism may be provided to keep the door 220 in its closed position. Also the lock mechanism could be based on magnetic elements which allow for engaging the lock mechanism through the wall of the transfer box 200’. While using the transfer box 200’ to store or transport the element 160 or the further element 161 , the door 220 may be kept close, thereby protecting the element 160, 161 from contamination. In some scenarios, the interior or the transfer box 200’ may be filled with a high-purity industrial gas, e.g., high-purity nitrogen having a purity level of higher than 99.99%, or even higher than 99.999%. A slight overpressure, relative to the outside atmosphere, inside the transfer box 200’ may help in maintaining the seal of the door 220 against the interior surface of the transfer box 200’. The pressure difference between the interior of the box and the outside atmosphere may be 1 ,5 bar or more.

[0065] For attaching the transfer box 200’ to the port 115, the transfer box 200 may be provided with an attachment portion, e.g., a flange which mates with a corresponding flange on the port 115. Clamps and / or screws may be used for attaching the transfer box 200’ to the port 115. Further, an O-ring or similar sealing element may be used for ensuring the vacuum seal between the attachment portion of the transfer box 200’ and the port 115.

[0066] As further illustrated, the transfer box 200’ otherwise forms a closed case which houses the further element 161 for replacement of the element 160 currently mounted inside the vacuum chamber 110. For this purpose, the transfer box 200’ may be provided with a storage section where the further element 161 is placed. While the further element 161 is placed in the storage section, the further element 161 does not obstruct the access to the opening 210 from inside the transfer box 200’.

[0067] In the state as illustrated in Fig. 4, the transfer box 200’ is not yet attached to the port 115, and the external portion of the port 115 is open to the outside atmosphere. Vacuum inside the vacuum chamber 110 is still ensured by the seal provided between the lid part 162 of the element 160 and the outer surface of the port 115. During normal operation of the MSEM 100 the lid part 162 may be secured by screws to the port 115. However, even if the screws are removed, e.g., before attaching the transfer box 200’, the vacuum inside the vacuum chamber 110 remains intact due to the pressure difference between the vacuum chamber 110 and the outside atmospheric pressure, which pushes the lid part 162 onto the outer surface of the port 115.

[0068] As further illustrated, the transfer box 200’ is provided with a set of linear manipulators 250, 260 which can be used to move the elements 160, 161 within the transfer box 200’ and through the opening 210. In the illustrated example, the linear manipulators 250, 260 include a first linear manipulator 250 for moving the elements 160, 161 along a first spatial direction denoted by “A” and a second linear manipulator 250 for moving the elements along a second spatial direction denoted by “B”. The first direction extends along an axis of the port 115, and the second direction extends transversely to the first direction, in the illustrated example substantially perpendicular to the first direction. Each linear manipulator is provided with a grip mechanism that can engage the respective lid part 162 of the elements 160, 161. As regards the implementation of the manipulators 250, 260, various known types of manipulator or mechanical feedthrough may be used, which are compatible with the required level of vacuum inside the transfer box 200’. For example, the manipulators 250, 260 could be based on driving movement inside the transfer box 200 from outside using elements like metallic membranes, spring bellows, special elastomer seals, magnetically coupled systems, or differentially pumped seals.

[0069] FIGs. 5A-5J illustrate different stages of the further process of replacing the element 160 with the further element 161 , using the transfer box 200’.

[0070] In the stage illustrated by FIG. 5A, the transfer box 200’ is still gas-filled and the door 220 is closed. In this condition, the transfer box 200’ is attached in a vacuum-tight manner to the port 115.

[0071] In the stage illustrated by Fig. 5B, the door 220 is opened, e.g., by operation of an actuating mechanism. In some scenarios, opening of the door 220 could also be driven by gravitational force acting on the door 220 and be initiated by simply unlocking the door 220. Further, it would be possible to drive opening of the door 220 by pressurizing the external space of the port 115 between the lid part 162 of the element 160 and the door 220, using the vent line 184.

[0072] In the stage illustrated by FIG. 5C, after opening the door 220, the first linear manipulator 250 is moved forward to engage with the lid part 162 of the element 160. The transfer box 200’ is then evacuated, using the pump 185. As a result, the pressure difference between the vacuum chamber 110 and the interior of the transfer box 200’, which pushes the lid part 162 of the element 160 onto the outer surface of the port 115, is significantly reduced. Evacuation of the transfer box 200’ is however not performed up to the same level of vacuum as inside the vacuum chamber 110, so that there is still some residual pressure difference between the vacuum chamber 110 and the interior of the transfer box 200 remaining, which however allows for pulling the element 160 from the port 115, as further explained below. It is noted that the typical level of vacuum inside the vacuum chamber 110 corresponds to UHV and that the level of evacuation inside the transfer box 200 may correspond to UHV as well or to a lower degree of vacuum, e.g., HV or of even lower degree.

[0073] In the stage illustrated by FIG. 5D, the first linear manipulator 250 is retracted to pull the element 160 from the port 115. To pull the element 160 from the port 115, the first linear manipulator 250 needs to exert sufficient pulling force on the element 160 so that the forces resulting from the residual pressure difference between the vacuum chamber 110 and the interior of the transfer box 200’ are overcome.

[0074] In the stage illustrated by FIG. 5E, the element 160 has been pulled into a storage section within the transfer box 200’, so that the opening 210 of the transfer box 200 is not obstructed by the element 160. The second linear manipulator 260 is then moved forward to engage with the lid part 162 of the further element 161 .

[0075] In the stage illustrated by FIG. 5F, the further element 161 has been pushed by the second linear manipulator 260 to a position where it is substantially aligned with the axis of the port 115 and in reach of the first linear manipulator 250. In the stage illustrated by FIG. 5G, the first linear manipulator 250 has been disengaged from the lid part 162 of the element 160 and moved forward to engage with the lid part 162 of the further element 161 , so that the further element can be pushed forward by the first linear manipulator 250. In the stage illustrated by FIG. 5H, the further element 161 has been completely pushed into the port 115, so that the lid part 162 of the further element 161 forms a vacuum seal with the outer surface of the port 115. The transfer box 200’ is then vented or re-filled with high-purity gas, using the vent line 184. As a result, the pressure difference between the vacuum chamber 110 and the interior of the transfer box 200’ increases, so that the lid part 162 of the further element 161 is further pushed onto the outer surface of the port 115, thereby further enhancing the vacuum seal of the lid part 162 with respect to the port 115.

[0076] In the stage illustrated by FIG. 5I, the first linear manipulator 250 has been disengaged from the lid part 162 of the element 161 , and the transfer box 200 completely vented or filled with high-purity gas. Further, the door 220 has been closed, e.g., using the actuating mechanism. In addition, the door 220 may be locked in the closed state. In this condition, the transfer box 200’ is ready to be detached from the port 115. In the stage illustrated by FIG. 5J, the transfer box 200’ has been detached from the port 115. The cover 116 may then be again placed on the port 115. Before placing the cover 116 on the port 115, screws for fixing the lid part 162 of the further element 161 on the port 115 may be installed.

[0077] As can be seen, using the processes of FIGs. 5A-5I, the elements 160, 161 may be exchanged in an efficient manner, without breaking the vacuum inside the vacuum chamber 110. A temporary increase of pressure in the vacuum chamber 110 due to opening the vacuum chamber 110 towards the interior of the transfer box 200’ may be quickly compensated by continuous pumping on the vacuum chamber 110 during the exchange process, e.g., using one or more of the pumps 181 , 182, 183. It is noted that the temporary increase of the pressure in the vacuum chamber 110 during the illustrated process, which may reach up to a few orders of magnitude, was found to not affect the vacuum conditions in the vacuum chamber 110 in the long term. For example, UHV conditions may recover within a few hours following the end of the procedure of exchange of the element 160 against element 161 .

[0078] FIGs. 6A, 6B, 7A, 7B, 8A, 8B, 9A, 9B, 10A, and 10B further illustrate how the elements 160, 161 may be moved to, from, and inside the transfer box 200. It is however noted that similar processes may also be performed in case of the transfer box 200’. In addition to the above-mentioned first linear manipulator 250 and second linear manipulator 260, these processes involve a third linear manipulator 270, which may be implemented in a similar way as the linear manipulators 250, 260. As a result, the elements 160, 161 can be moved in three different spatial directions to facilitate transferring the elements 160, 161 to different storage sections within the transfer box 200.

[0079] FIGs. 6A and 6B illustrate an initial stage of the exchange process, corresponding to the stage of FIGs. 3A and 5A. FIG. 6A shows a side view, similar to FIGs. 3A and 5A, and FIG. 6B shows a top view. As can be seen from FIGs. 6A and 6B, the three linear manipulators 250, 260, 270 are operable to move the elements 160, 161 in three mutually perpendicular directions: The first linear manipulator 250 is configured for movements along the axis of the port 115. The second linear manipulator 260 is configured for movements along a vertical axis, and the third linear manipulator 270 is configured for movements along a horizontal axis. Each linear manipulator 250, 260, 270 is based on multiple parallel rods, thereby enhancing stiffness with respect to rotational movements. In the stage of FIGs. 6A and 6B, the transfer box 200 is attached to the port 115 (not illustrated), but the linear manipulators 250, 260, and 270 are not yet engaged with the elements 160, 161.

[0080] FIGs. 7A and 7B illustrate a further stage of the exchange process. FIG. 7A shows a side view, and FIG. 7B shows a top view. In the stage of FIGs. 7A and 7B, the first linear manipulator 250 has pulled the element 160 into the transfer box 200, to a position where the element 160 is in reach of the third linear manipulator 270.

[0081] Further, the second linear manipulator 260 has engaged the further element 161 to push it vertically from a first storage section of the transfer box 200 towards the axis of the port 115, to a position where the further element can be engaged by the first linear manipulator 250.

[0082] FIGs. 8A and 8B illustrate subsequent further stage of the exchange process. FIG. 8A shows a side view, and FIG. 8B shows a top view. In the stage of FIGs. 8A and 8B, the first linear manipulator 250 has disengaged from the element 160, and the third linear manipulator 270 has engaged with the element 160 and pushed it horizontally to a second storage section of the transfer box 200.

[0083] FIGs. 9A and 9B illustrate subsequent further stage of the exchange process. FIG. 9A shows a side view, and FIG. 9B shows a top view. In the stage of FIGs. 9A and 9B, the second linear manipulator 260 has pushed the element 161 to a position on the axis of the port 115, and the first linear manipulator 250 has engaged with the element 161 and to push it into the port 115.

[0084] FIGs. 10A and 10B illustrate subsequent further stage of the exchange process. FIG. 10A shows a side view, and FIG. 10B shows a top view. In the stage of FIGs. 10A and 10B, the second linear manipulator 260 has disengaged from the further element 161 , and the first linear manipulator 250 has pushed the element 161 into the port 115. As a result, the element 160 is now stored in the second storage section of the transfer box 200, and the further element is transferred to its installation position in the vacuum chamber 110.

[0085] It is noted that the above-described implementations of the transfer box 200 or the transfer box 200’ using two or three linear manipulators are illustrative examples, and that other configurations of manipulators could be used as well. Figs. 11 A, 11 B, and 12 illustrated some further examples of manipulator configurations that could be used in modified versions of the transfer box 200 or of the transfer box 200’.

[0086] In the example of FIGS. 11A and 11 B, two manipulators 310, 320 are provided, each configured to move a respective one of the element 160 and the further element 161 along a bow-shaped trajectory. Using the manipulator 310, the element 160 can be moved along a first bow-shaped trajectory, which extends between the port 115 and a first storage section of the transfer box. Using the manipulator 320, the further element 161 can be moved along a second bow-shaped trajectory, which extends between the port 115 and a second storage section of the transfer box. The second storage section is vertically offset from the first storage section. Towards the port 115, the first bow-shaped trajectory and the second bow-shaped trajectory converge to the axis of the port. FIG. 11A shows both elements 160, 161 in their respective storage section. FIG. 11 B shows the further element 161 in a state where it has been pushed by the second manipulator 320 into the port 115, while the element 160 remains in its storage section.

[0087] In the example of FIG. 12, the transfer box is provided with a flexible portion 410 that connects the attachment portion 420 of the transfer box to a storage section part 430 of the transfer box. A single linear manipulator 450 is provided and can be used for either moving the element 160 between the port 115 and a first storage section within the storage section part 430 or moving the further element 161 between the port 115 and a first storage section within the storage section part 430. The flexible portion 410 allows for moving of the storage section part 430 with respect to the attachment portion 420, so that either the first storage section or the second storage section can be aligned with the port 115 and the linear manipulator 450.

[0088] In some cases, the elements 160, 161 may require an electrical connection to an electronics system outside the vacuum chamber. For example, when the elements 160, 161 constitute aperture-plate modules or multi-aperture plate modules for beam conditioning, electric and / or magnetic fields may be generated in the vicinity of the aperture hole(s), and electric signals to control the electric and / or magnetic fields may be provided by the electronics system. For this purpose, the elements 160, 161 may be provided with an electronics connector. FIGs. 13A and 13B illustrate a corresponding example.

[0089] In the example of FIGs. 13A and 13B, an electronics connector 165 is provided on the outside of the lid part 162 of the element 161. The electronics connector 165 could for example be a Sub-D connector. For connection to the electronics system 500, a complementary connector 510 is provided on the electronics system 500, e.g., on a cable or on a directly connectable electronics module of the electronics system 500. By way of example, the electronics connector 165 could be a male Sub-D connector and the complementary connector 510 could be a female Sub-D connector.

[0090] During operation of the MSEM 100, there may be a risk of the outer parts of the element 161 being contaminated by extended exposure to the outside atmosphere, which may in turn affect the achievable quality of vacuum inside the transfer box 200, 200’. The cover 116 illustrated in FIG. 1 may help to avoid such contamination. However, also the possibility of an electric connection to the element 161 may need to be accommodated. FIGs. 14A, 14B, 15A, 15B, 16A, and 16B illustrate examples of how the contamination risk for outer parts of the element 160 can be reduced while still being able to provide the connection to the electronics system 500.

[0091] In the example of FIGs. 14A and 14B, a cover 600 is utilized which has a feedthrough connector. A first part 650 of the feedthrough connector mates with the electronics connector 165 of the element 161 , and a second part 660 of the feedthrough connector mates with the complementary connector 510 of the electronics system. The cover 600 can be installed in a sealed manner on the port 115. An O-ring 610 may be used as part of the sealing mechanism and be fitted on the cover 600. The O-ring may for example be made of FKM (Fluorine Kautschuk Material), but other types of O-ring or sealing could be used as well. The cover 600 may be fixed on the port 115 by using screws or a clamp. FIG. 14A illustrates the cover 600 detached from the port 115 and the electronics system 500. FIG. 14B illustrates the cover 600 mounted on the port 115, with the electronics system 500 connected.

[0092] In the example of FIGs. 15A and 15B, a cover 700 is utilized which provides direct access to the electronics connector 165. The cover 700 can be installed in a sealed manner on the port 115. An O-ring 710 may be used as part of the sealing mechanism and be fitted on the cover 700. The O-ring may for example be made of FKM. The cover 900 may be fixed on the port 115 by using screws or a clamp. On the side of the electronics system 500, a further cover 800 is provided which has a removable lid 820. When the electronics system 500 is disconnected, the lid 820 may be installed, like illustrated in FIG. 15A. The lid 820 may for example be fixed by a clamp to the further cover 800. An O-ring 810, e.g., formed of FKM, may be fitted to the further cover 800 to enhance the seal between the further cover 800 and the lid 820. In this state, the complementary connector 510 and its surrounding are protected from contamination. As a result, also the risk of the electronics connector 165 being contaminated by contact with the complementary connector 510 and its surrounding can be reduced. If the electronics system 500 is connected, the lid 820 is removed and the further cover 800 is mounted in a sealed manner to the cover 700, with the electronics connector 165 and the complementary connector 510 directly fitting, as illustrated in FIG. 15B.

[0093] In the example of FIGs. 16A and 16B, a cover 900 is utilized which is mounted on the electronics system 500 and allows for mating the electronics connector 165 and the complementary connector 510. If the electronics system 500 is connected, the cover 900 forms a seal with the outer surface of the port 115, with the electronics connector 165 and the complementary connector 510 directly fitting, as illustrated in FIG. 16B. An O-ring 910 may be used as part of the sealing mechanism and be fitted on the cover 900. The O-ring may for example be made of FKM. The cover 900 may be fixed on the port 115 by using screws or a clamp.

[0094] It is noted that while FIGs. 13A, 13B, 14A, 14B, 15A, 15B, 16A, 16B refer to the further element 161 , similar considerations also apply to the element 160. FIG. 17 illustrates a further example of the transfer box 200”. The example of FIG. 17 is generally similar to that of FIG. 4. However, in this case the transfer box 200” is further provided with a gas port 201 for connection to the pump 185 and vent line 184. The transfer box 200” may be utilized in a similar manner as the transfer box 200’, however using the gas port 201 to evacuate the transfer box 200” and to vent or fill the transfer box with high-purity gas. It would further be possible to use both the gas port 201 on the box 200” and a pump line and vent line on the port 115, as illustrated in Fig. 4. Further, it would be possible to connect a gas bottle or other container with high-purity gas to the gas port 201 for constantly pressurizing the transfer box 200” also during transport or storage, or to be used for re-pressurizing in the event of a pressure loss within the transfer box 200”.

[0095] FIG. 18 shows a flowchart for illustrating a maintenance method which is based on the above concepts. The method may be used for maintenance of the MSEM 100, using any of the above-described transfer boxes 200, 200’, 200”.

[0096] At step 1810, the transfer box 200, 200’, 200” is attached in a vacuum-tight manner to the port 115 of the vacuum chamber 110 of the MSEM 100. This is accomplished while the vacuum chamber 110 is in evacuated condition and the port 115 is sealed from outside by the lid part 162 of the first element 160 inserted into the vacuum chamber 110. The transfer box 200, 200’, 200” encloses the second element 161 which is intended to replace the first element. The opening 210 of the transfer box 200, 200’, 200” is aligned with the port 115.

[0097] In the case of the transfer box 200, 200” equipped with the door 220, the transfer box 200’; 200” may be filled with a high purity gas, e.g., high-purity nitrogen, before it is attached to the port 115.

[0098] In the case of the transfer box 200’, 200” equipped with the door 220, the door 220 may be opened at step 1820, when the transfer box 200’, 200” is attached to the port 115. In some scenarios, an overpressure in the box may be released between attachment to the vacuum chamber and opening the door.

[0099] At step 1830, the transfer box 200, 200’, 200” attached to the port 115 is evacuated. This may be accomplished using the pump 185. As mentioned above, the pump 185 may be connected to the port 115 of the vacuum chamber 110 or to a gas port of the transfer box 200”. At step 1840, the first element 160 is pulled from the port 115, through the opening 210, and into the transfer box 200, 200’, 200’. This is accomplished while the transfer box 200, 200’, 200” is in the evacuated condition. The transfer box 200, 200’, 200” comprises at least one manipulator, such as the above-mentioned manipulators 250, 260, 270, 310, 320, or 420, that may be used for this purpose.

[0100] At step 1850, the second element 161 is pushed through the opening 210 from the box 200, 200’, 200” into the port 115, thereby sealing the port 115 from outside by the lid part 162 of the second element 161. The transfer box 200, 200’, 200” comprises at least one manipulator, such as the above-mentioned manipulators 250, 260, 270, 310, 320, or 420, that may be used for this purpose.

[0101] At step 1860, the transfer box 200, 200’, 200’ attached to the port 115 is vented. In some scenarios, this venting of the transfer box 200, 200’, 200” may be accomplished with a high-purity gas, e.g., high-purity nitrogen. In this case, step 1860 may involve filling or even pressurizing the transfer box 200, 200, 200” with the high- purity gas.

[0102] In the case of the transfer box 200, 200” equipped with the door 220, the door 220 may be closed at step 1870, when the second element 161 is inserted into the vacuum chamber 110, the port 115 is sealed by the lid part 162 of the second element, and the transfer box 200’, 200” is vented. In some scenarios, an overpressure in the box may be built up after closing the door.

[0103] At step 1880, the transfer box 200; 200’; 200” is detached from the port 115. After detaching the transfer box 200, 200’, 200” from the port 115, attaching a cover may be attached to the port 115, such as the above-mentioned cover 116, 600 or 700. In some scenarios, the cover may have a feed-through connector which mates with an electronics connector on the lid part 162 of the second element 161 , e.g., as explained for the cover 600. In some scenarios, the cover may have an opening which provides access to an electronics connector on the lid part of the second element 161 , e.g. , as explained for the cover 700.

[0104] In the case of the transfer box 200, 200” equipped with the door 220, while the transfer box 200’, 200” is not attached to the port 115, a sealing pressure of the door 220 against an inner sealing surface of the transfer box 200’, 200” may be based on pressure within the box 200’, 200”, in particular a pressure difference between the interior of the box and the outside atmosphere.

[0105] As can be seen, the illustrated concepts may be used for efficiently enabling maintenance of a multi-beam charged-particle microscope, such as an MSEM. Specifically, an element in the vacuum chamber of the multi-beam charged-particle microscope may be replaced in an efficient manner, without having to break the vacuum in the vacuum chamber.

[0106] Although the invention has been shown and described with respect to certain preferred embodiments, equivalents and modifications will occur to others skilled in the art upon the reading and understanding of the specification. The present invention includes all such equivalents and modifications and is limited only by the scope of the appended claims.

[0107] Further, it is noted that while the illustrated concepts have been explained in connection with a multi-beam charged-particle microscope, the concepts could be applied in a corresponding manner to other systems equipped with a vacuum chamber including elements that may require replacement, e.g., in a multi-beam particle irradiation system.

Claims

C L A I M S1 . A method for maintenance of a multi-beam charged-particle microscope (100), comprising:- attaching a box (200; 200’; 200”) in a vacuum-tight manner to a port (115) of a vacuum chamber (110) of the multi-beam charged-particle microscope (100), while the vacuum chamber (110) is in evacuated condition and the port (115) is sealed from outside by a lid part (162) of a first element (160) inserted into the vacuum chamber (110), wherein the box (200; 200’; 200”) encloses a second element (161 ) for replacing the first element (160) and is provided with an opening (210) aligned with the port (115);- evacuating the box (200; 200’; 200”) attached to the port (115);- while the box (200; 200’; 200”) is in the evacuated condition, pulling the first element (160) from the port (115) through the opening (210) into the box (200; 200’; 200”);- while the box (200; 200’; 200”) is in the evacuated condition, pushing the second element (161 ) through the opening (210) from the box (200; 200’; 200”) into the port (115), thereby sealing the port (115) from outside by a lid part (162) of the second element (161 );- venting the box (200; 200’; 200”) attached to the port (115); and- detaching the box (200; 200’; 200”) from the port (115).

2. The method according to claim 1 , wherein the box (200’; 200”) comprises a door (220) for sealing the opening (210) from inside the box (200’; 200”) while the box (200’; 200”) is not attached to the port (115).

3. The method according to claim 2, comprising: opening the door (220) when the box (200’; 200”) is attached to the port (115); and closing the door (220) when the second element (161 ) is inserted into the vacuum chamber (110) and the port (115) is sealed by the lid part (162) of the second element (161 ).

4. The method according to claim 2 or 3, wherein said venting of the box (200’; 200”) is accomplished with a high-purity gas.

5. The method according to any of claims 2 to 4, wherein before attaching the box (200’; 200”) to the port (115), the box (200’;200”) is filled with a high-purity gas.

6. The method according to any of claims 2 to 5, wherein, while the box (200’; 200”) is not attached to the port (115), a sealing pressure of the door (220) against an inner sealing surface of the box (200’; 200”) is based on a pressure difference between an interior of the box (200; 200’; 200”) and the outside atmosphere.

7. The method according to any of the preceding claims, wherein the box (200; 200’; 200”) comprises at least one manipulator (250, 260, 270; 310, 320; 450) for moving the first element (160) and the second element (161 ).

8. The method according to claim 7, wherein the at least one manipulator (250, 260, 270; 310, 320; 450) is configured for moving at least one of the first element (160) and the second element (161 ) in at least two different spatial directions.

9. The method according to claim 7 or 8, wherein the at least one manipulator (250, 260, 270; 310, 320; 450) comprises at least a first linear manipulator and a second linear manipulator.

10. The method according to any of the preceding claims, wherein the box (200; 200’; 200”) comprises a flexible portion (410) which enables displacing a first part of the box (200; 200’; 200”), which holds the first element (160) or the second element (161 ), with respect to a second part of the box (200; 200’; 200”), which is attached to the port (115).11 . The method according to any of the preceding claims, comprising: after detaching the box (200; 200’; 200”) from the port (115), attaching a cover (600; 700) to the port (115).

12. The method according to claim 11 , wherein the cover (600) has a feed-through connector (650, 660) which mates with an electronics connector (165) on the lid part (162) of the second element (161 ).

13. The method according to claim 11 , wherein the cover (700) has an opening which provides access to an electronics connector (165) on the lid part (162) of the second element (161 ).

14. The method according to any of the preceding claims, wherein at least one of the first element (160) and the second element (161 ) is a multi-aperture plate module for conditioning multiple charged-particle beams (121 ) of the multi-beam charged-particle microscope (100).

15. A box (200; 200’; 200”) for maintenance of a multi-beam charged-particle microscope (100), the box (200; 200’; 200”) comprising:- an attachment portion for attaching the box (200; 200’; 200”) in a vacuum- tight manner to a port (115) of a vacuum chamber (110) of the multi-beam charged- particle microscope (100), while the vacuum chamber (110) is evacuated and the port (115) is sealed from outside by a lid part (162) of a first element (160) inserted into the vacuum chamber (110),- an opening (210) which aligns with the port (115) when the box is attached to the port (115);- at least one manipulator (250, 260, 270; 310, 320; 450) for, while the box is in the evacuated condition, pulling the first element (160) from the port through the opening (210) into the box and for pushing a second element (161 ) enclosed in the box through the opening (210) from the box into the port (115), thereby sealing the port (115) from outside of the vacuum chamber (110) by a lid part (162) of the second element (161 ).

16. The box (200; 200’; 200”) according to claim 15, wherein the box (200; 200’; 200”) comprises a door (220) for sealing the opening (210) from inside the box (200; 200’; 200”) while the box (200; 200’; 200”) is not attached to the port (115).

17. The box (200; 200’; 200”) according to claim 15 or 16, wherein the at least one manipulator (250, 260, 270; 310, 320; 450) is configured for moving at least one of the first element (160) and the second element (161 ) in at least two different spatial directions.

18. The box (200; 200’; 200”) according to any of claims 15 to 17, wherein the at least one manipulator (250, 260, 270; 310, 320; 450) comprises a first linear manipulator and a second linear manipulator.

19. The box (200; 200’; 200”) according to any of claims 15 to 18, wherein the box (200; 200’; 200”) comprises a flexible portion (410) which enables displacing a first part of the box (200; 200’; 200”), which holds the first element (160) or the second element (161 ), with respect to a second part of the box (200; 200’; 200”), which is attached to the port (115).

20. The box (200; 200’; 200”) according to any of claims 15 to 19, wherein the box (200; 200’; 200”) comprises at least one gas port (201 ) for evacuating and venting the box (200; 200’; 200”) attached to the port (115).21 . The box (200; 200’; 200”) according to any of claims 15 to 20, wherein at least one of the first element (160) and the second element (161 ) is a multi-aperture plate module for conditioning multiple charged-particle beams (121 ) of the multi-beam charged-particle microscope (100).

22. A system, comprising:- at least one box (200; 200’; 200”) according to any of claims 15 to 21 ; and- the multi-beam charged-particle microscope (100).

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