Charged particle microscope having charged particle detector

Abstract

To provide an improved charged particle microscope.SOLUTION: A charged particle microscope M incorporates dual data stream output interfaces 101, 102 within an imaging system. These interfaces enable the microscope to capture and process data from a charged particle camera in two distinct ways, leading to enhanced imaging capabilities and improved flexibility. This invention has the potential to significantly advance the field of charged particle microscopy and find applications in various scientific and industrial fields.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to charged particle microscopes for imaging samples, and more particularly to systems that utilize a charged particle optical column, a sample holder, a charged particle camera, and an imaging system to generate detailed images of a sample. [Background technology]

[0002] In a variety of sciences and industries, it is often necessary to study the microscopic structure and composition of a sample. Traditional optical microscopes have limited resolution and cannot provide sufficient detail for certain types of samples. To overcome these limitations, charged particle microscopes have been developed.

[0003] Charged particle microscopy is a well-known and increasingly important technique for imaging microscopic objects, particularly in the form of electron microscopy. To date, the basic type of electron microscope has evolved into several well-known instrument types, such as transmission electron microscopes (TEMs), scanning electron microscopes (SEMs), and scanning transmission electron microscopes (STEMs), as well as various variants, such as so-called "dual beam" instruments (e.g., FIB-SEMs) that additionally employ a focused ion beam (FIB) to enable supporting functions such as ion beam milling or ion beam induced deposition (IBID). Those skilled in the art will be familiar with the different types of charged particle microscopy.

[0004] These charged particle microscopes typically include several components, which are described below.

[0005] First, a charged particle microscope comprises a charged particle optical column that is used to direct a beam of charged particles to a sample, and is responsible for directing and controlling the charged particles to the sample to ensure accurate imaging.

[0006] Additionally, charged particle microscopes are equipped with a specimen holder to hold the specimen securely in place during the imaging process. Specimen holders are typically designed to accommodate a variety of specimen sizes and shapes, providing stability and reproducibility in positioning.

[0007] Additionally, the charged particle microscope includes a charged particle camera for capturing charged particles interacting with the sample, which converts the energy or intensity of the charged particles into electrical signals that can be further processed to generate an image.

[0008] The charged particle microscope also includes an imaging system positioned to process signals from the charged particle camera, the imaging system receiving data from the charged particle camera and generating an image signal based on the collected information.

[0009] Charged particle microscopes include a charged particle camera output interface, which allows the output of data streams associated with the charged particle camera. In modern imaging systems, especially those incorporating transmission electron microscope (TEM) cameras, output interfaces are designed to provide the highest image quality, with a focus on high data reliability and minimizing data loss.

[0010] In the area of ​​charged particle microscopy, especially in transmission electron microscopy (TEM), significant challenges remain for certain applications, such as drift correction based on active images, field correction for tilt-sequential tomography, and methods for measuring system state. Current systems show limitations, especially in the context of electron-counting cameras, where electron-counting algorithms play a key role.

[0011] Therefore, there is a need for a system and method that effectively supports these applications without compromising the overall performance of the imaging system. Summary of the Invention

[0012] It is therefore an object of the present disclosure to provide improved charged particle microscopes and / or improved methods. In particular, it is an object of the present disclosure to provide a charged particle microscope that allows real-time feedback without compromising data reliability, while minimizing data loss.

[0013] To this end, the present disclosure provides a charged particle microscope as defined in claim 1. The charged particle microscope disclosed herein includes a charged particle optical column. The column is arranged to direct a charged particle beam, such as an electron beam or an ion beam, toward a sample. The system also includes a sample holder for securing the sample. The system includes a charged particle camera and an imaging system. The imaging system generates an image signal based on information from the detector camera. The imaging system has a first output interface. The interface outputs a first data stream of data related to the camera.

[0014] As defined herein, the charged particle microscope further comprises a second charged particle camera output interface for outputting a second data stream of data associated with the charged particle camera, and in this sense, the charged particle microscope and the first and second charged particle camera output interfaces are arranged such that the second data stream is different compared to the first data stream.

[0015] In accordance with this finding, the disclosed charged particle microscope provides an effective and innovative solution to the problem of providing real-time feedback while maintaining high data quality and reliability. By having two charged particle camera output interfaces arranged to provide different data streams, the system can have two separate data streams that can be used for different purposes.

[0016] As an example, the first data stream can be designed to prioritize data quality and reliability, ensuring accurate and reliable data output (i.e., maintaining the high image quality standards of currently known charged particle microscopes).

[0017] The second data stream is designed to be optimized with low and / or fixed latency, making one or more critical parameters available for real-time feedback to the charged particle system. The addition of this second output interface and the placement of the second data stream distinct from the first data stream enables real-time feedback desirable (or even required) for certain applications, such as active image-based drift correction, field of view correction for continuous tilt tomography, or a method for measuring system state. Thus, the dual output interface design of the charged particle microscope achieves a balance not achievable in previous systems by ensuring both 1) high data quality and reliability and 2) the provision of real-time feedback.

[0018] As defined herein, delay refers to the time difference between the moment a charged particle contacts the charged particle camera and the time information from that charged particle is available to a device downstream of the output interface. Examples of such devices that may be present or configured downstream of the output interface include data storage, feedback processing equipment, control equipment, etc. Delay may refer to an average time difference or a maximum time difference.

[0019] In an embodiment suitable for charged particle microscopy, the delay period is on the order of half the readout integration time of the charged particle camera. For example, if a charged particle camera, such as a TEM camera, operates at 500 fps, it takes 2 ms to read out all pixels. Low latency means that the time it takes for data to be output from the charged particle camera and output through the second output interface (where it can then be used, for example, by further processing equipment) is also on the order of pixel readout. This means that low latency values ​​should be on the order of ms. Based on this example, the average latency should be on the order of 1 ms, and the maximum latency should be around 2 ms. It should be noted that good results can also be obtained with delay periods of up to 6 ms.

[0020] Therefore, the poor tolerability may be related to the frame rate of the charged particle camera, the average poor tolerability may be on the order of half the readout integration time, and the maximum delay may be on the order of the readout integration time.

[0021] In summary, the present disclosure describes a charged particle microscope with a dual output data interface that can be used for different data streams, such as one that is optimized for low tolerance, thereby increasing the efficiency of a real-time charged particle microscope platform, and one that is optimized for high quality and reliable data, thereby maintaining the high image quality of the charged particle microscope, thereby achieving the objectives of the present disclosure.

[0022] Further examples are described below.

[0023] In an embodiment, the charged particle microscope is arranged such that the second data stream is optimized for low latency output.

[0024] Such low latency output can be defined by a maximum low latency output of 750 ms, and a maximum low latency transmission of 250 ms. In the example, the system has an average latency (delay) of 10 0 ~10 1 It is designed in the order of ms (e.g., 1 to 50 ms), with a range of 2 to 8 ms being desirable.

[0025] As mentioned above, the maximum low latency output may be related to the frame rate of the charged particle camera. For a frame rate of 500 fps, the maximum low latency is preferably in the order of 1 / 500 = 2 ms. For lower frame rates (e.g., 250 fps), the maximum low latency is 1 / 250 = 4 ms. To achieve acceptable results, higher latency (10 times higher, i.e., in the order of 10 ms, or even 100 ms) may be used.

[0026] Additionally or alternatively, the charged particle microscope may be arranged such that the second data stream has a substantially fixed low latency output. Such a fixed low latency output may have an average latency output below 100 ms. In an example, the system may have an average latency (delay) of 1, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 100, 200, 300, 400, 500, 600, 700, 800, 900, 10 ... 0 ~10 1 It is designed in the order of ms (e.g., 1 to 50 ms), with a range of 2 to 8 ms being desirable.

[0027] In an embodiment, the charged particle microscope is arranged so that the second data stream has an average low latency output of 100 ms or less and a maximum low latency output of 750 ms or less, preferably 250 ms or less.

[0028] As mentioned above, the average low latency output can be related to the frame rate of the charged particle camera. For a frame rate of 500 fps, the average low latency is preferably on the order of 0.5*1 / 500=1 ms. For lower frame rates (e.g., 250 fps), the average low latency can be 0.5*1 / 250=2 ms.

[0029] The charged particle microscope may be arranged in such a way that the second data stream is arranged to have an output with less delay compared to the first data stream. The delay of the second data stream may be at least an order of magnitude less than the delay of the first data stream. For example, the delay of the second data stream may be two orders of magnitude less than the delay of the first data stream. For example, the delay in storing high quality data using the first data stream may be at most a few seconds (i.e., 10 3 ms), while the low-latency second data stream has a maximum delay of tens of microseconds (i.e., 10 1 ms order) as follows:

[0030] In one embodiment, the charged particle microscope is configured such that the charged particle microscope and the second charged particle camera output data interface are connected and configured to utilize the image signal from the imaging system to provide real-time feedback to the charged particle microscope. This is particularly useful when the second charged particle camera output is configured to provide a low-latency and / or fixed-latency output, as described above. This low-latency and / or fixed-latency output allows for the establishment of a real-time feedback loop, which is useful in applications such as active image-based dock compensation, continuous tilt tomography field correction, or system state metrology. Other applications of the real-time feedback loop described herein are also contemplated.

[0031] In some embodiments, the first data stream is configured to be optimized for reliability, which in other embodiments includes optimizing the first data stream for complete data transfer without significant data loss. This means that data is transferred without corrupted information packets. In some embodiments, a checksum of the data packets may indicate a transmission error. The charged particle microscope and / or imaging system may be configured to accommodate a transmission error, causing the receiver to request a retransmission of the information packets. For the second data stream, if low latency is required, the charged particle microscope and / or imaging system may be configured to mark the data stream as "bad" whenever a transmission error is indicated, although this does not result in retransmission of data to prevent delay accumulation / fluctuation.

[0032] In one embodiment, the charged particle microscope includes a data processing unit located upstream of the first and second charged particle camera output interfaces. The data processing unit is configured to process raw data input from the charged particle camera chip in a first step before sending the raw data to the camera output interface. The data processing unit may be, for example, an FPGA, an ASIC, and / or a GPU that is part of the charged particle camera. Thus, the charged particle camera may include a charged particle camera chip connected to a data processing unit downstream of the charged particle camera chip. The data processing unit is connected to a second charged particle camera output interface located downstream of the data processing unit.

[0033] The data processing unit may be processing hardware contained within or may be an inherent part of a charged particle camera, such as a TEM camera. The data processing unit may comprise one or more of an FPGA, a GPU, and a CPU. The data processing unit may be arranged to run processing algorithms on raw data input from the sensor chip.

[0034] The data processing unit may be arranged to process the data provided to the second charged particle camera output interface.

[0035] The data processing unit may also, or alternatively, be arranged to process data provided to the second charged particle camera output interface.

[0036] The first charged particle camera output may be arranged to output the data from the data processing unit. A storage server system connected to the charged particle microscope may be arranged to accumulate the data output from the charged particle camera and to accumulate data processed by the data processing unit. The data stored in the storage server system may then be post-processed, for example after an imaging experiment of the sample is completed.

[0037] In one embodiment, the charged particle microscope includes a feedback data processing device configured downstream of the second charged particle camera output interface, such that data from the second output data interface can be processed for use as feedback data to the charged particle microscope.

[0038] In one embodiment, the charged particle camera is a charged particle camera, such as a TEM camera, positioned to acquire images from the sample. The TEM camera may operate in an integration mode, also known as integration mode. In another embodiment, the TEM camera may operate in an electron counting mode. An integration mode camera can use direct detection, or indirect detection, where a scintigraphy layer is used to convert electrons into light, which the camera detects. A counting camera can create "count frames" or EER data. Electron counting is an example of a low-level processing pipeline component that adds a small amount of latency. [Brief explanation of the drawings]

[0039] For a more detailed understanding of the present disclosure and its advantages, please refer to the following description taken in conjunction with the accompanying drawings. [Figure 1] 1 shows a longitudinal cross section of a charged particle microscope, in particular a transmission charged particle microscope. [Figure 2] 1 shows a longitudinal section of a charged particle microscope, in particular a scanning charged particle microscope. [Figure 3] 1 illustrates an embodiment of a charged particle microscope having an imaging system as defined herein. [Figure 4] 1 shows a further embodiment of a charged particle microscope having an imaging system as defined herein. DETAILED DESCRIPTION OF THE INVENTION

[0040] FIG. 1 (not to scale) is a highly schematic depiction of an embodiment of a charged particle microscope M, in accordance with an embodiment of the present invention. More specifically, it shows one form of transmission microscope M, in this case a TEM / STEM (although in the context of the present invention, an SEM (see FIG. 2), an ion-based microscope, etc. would be equally valid). In FIG. 1, within a vacuum enclosure 2, an electron source 4 generates a beam B of electrons propagating along an electron optical axis B′ and traversing an electron optical illuminator 6, which serves to direct / focus the electrons onto a selected portion of a sample S (which may, for example, be (locally) thinned / flattened). Also shown is a deflector 8, which (among other things) may be used to effect a scanning movement of the beam B.

[0041] The sample S is held in a sample holder H and can be positioned with multiple degrees of freedom by a positioning device / stage A, which moves a cradle A to which the holder H is (removably) fixed. For example, the sample holder H may be equipped with fingers that are (among other things) movable in the XY plane (see the depicted Cartesian coordinate system) (usually, movements parallel to Z and tilting about X / Y are also possible). Such movements allow different parts of the sample S to be illuminated / imaged / inspected by the electron beam B traveling along axis B' (Z direction) (and / or allow a scanning movement to be performed as an alternative to beam scanning). If necessary, an optional cooling device (not depicted) can be in intimate thermal contact with the sample holder H, thereby maintaining the sample holder H (and the sample S thereon) at, for example, cryogenic temperatures.

[0042] The electron beam B interacts with the sample S, causing various types of "stimulated" radiation to be emitted from the sample S, including (for example) secondary electrons, backscattered electrons, X-rays, and optical radiation (cathodoluminescence). If desired, one or more of these radiation types can be detected using an analytical device 22, e.g., a scintillator / photomultiplier tube or an EDX (energy dispersive X-ray spectroscopy) module. In such cases, images can be constructed using essentially the same principles as in an SEM. However, alternatively or supplementarily, electrons that traverse (pass through) the sample S and then exit it, continuing their propagation along axis B' (although in practice, typically with some deflection / scattering), can also be studied. This transmitted electron flux enters a projection system (projection lens 24), which typically consists of various components such as electrostatic / magnetic lenses, deflectors, and collectors (e.g., stigmators). In a conventional (non-scanning) TEM mode, this projection system 24 can focus the transmitted electron beam onto a phosphor screen 26. If necessary, the fluorescent screen 26 can be retracted (schematically indicated in the figure by arrow 26') so as to be out of the way of the axis B'. By means of the projection system 24, an image (or diffraction pattern) of (a part of) the sample S is formed on the screen 26, which can be observed through a viewing port 28 located at a suitable position in the wall of the enclosure 2. The retraction mechanism for the screen 26 can be, for example, mechanical and / or electrical in nature and is not shown here.

[0043] Instead of viewing an image on a screen 26, one can take advantage of the fact that the depth of focus of the electron beam emerging from the projection system 24 is typically quite large (e.g., on the order of one meter). As a result, various other types of analytical equipment can be used downstream of the screen 26, such as:

[0044] -TEM detector (camera) 30. In camera 30, the electron beam can be processed by controller / processor 20 to form a static image (or diffractogram) that is displayed on a display device (not shown), such as a flat panel display. When not needed, camera 30 can be retracted / recovered (as shown diagrammatically by arrow 30') so that it is off axis B'.

[0045] - a STEM detector (camera) 32. The output from camera 32 can be recorded as a function of the scanning position (X,Y) of beam B on sample S to construct an image that is a "map" of the output from camera 32 as a function of X,Y. Camera 32 may comprise a single pixel, e.g., having a diameter of 20 mm, as opposed to a matrix of pixels that is typically present in camera 30. Furthermore, camera 32 is typically configured to capture images at a rate of 100 kB per second (e.g., 100 kB / s). 2 much higher acquisition rates (e.g., 10 per second) 2 Again, when not needed, the camera 32 can be retracted / extended again (schematically indicated by arrow 32') so as to get out of the way of axis B' (although such retraction is not necessary, such as in the case of a doughnut-shaped annular dark field camera 32, where a central hole allows the light beam to pass through when the camera is not in use).

[0046] As an alternative to imaging using the camera 30 or 32, a spectroscopic detector 34, for example an EELS module, can also be activated.

[0047] It should be noted that the order / location of items 30, 32 and 34 is not strict and many possible variations are possible. For example, spectroscopic detector 34 could be integrated into projection system 24.

[0048] In the embodiment shown, the microscope M further comprises a retractable X-ray computed tomography (CT) module, generally designated by the reference numeral 40. In computed tomography (also called tomography), a source and a detector (opposing each other) are used to interrogate a sample along different lines of sight so as to obtain transmitted views of the sample from various viewpoints.

[0049] It should be noted that the detectors 30, 32, and 34 are part of an imaging system (generally designated by the reference numeral 200). The imaging system is arranged to generate image signals based on information from the charged particle detectors 30, 32, and 34, and can be part of the detectors or separate from the detectors. A controller (computer processor) 20 is connected to the various components shown via control lines (bus) 20′. This controller 20 can provide various operations such as synchronizing actions, providing set points, processing signals, performing calculations, and displaying messages / information on a display device (not shown). Of course, the (schematically drawn) controller 20 can be located (partially) inside or outside the enclosure 2 and can have a unitary or composite structure, as desired.

[0050] Those skilled in the art will understand that the interior of the enclosure 2 need not be maintained under strict vacuum conditions. For example, in so-called "environmental TEM / STEM," a background atmosphere of a given gas is intentionally introduced / maintained within the enclosure 2. Those skilled in the art will also understand that in practice it may be advantageous to confine the volume of the enclosure 2, possibly so that the enclosure 2 essentially encompasses the axis B', and to employ an electron beam that passes through and expands to take the form of a small diameter tube (e.g., about 1 cm in diameter) to house structures such as the source 4, sample holder H, screen 26, camera 30, camera 32, spectrometer 34, etc.

[0051] Referring now to Figure 2, another embodiment of the apparatus disclosed herein is shown. Figure 2 (not to scale) is a very schematic representation of a charged particle microscope M, more specifically showing an embodiment of a non-transmission microscope M, in this case an SEM (although in the context of the present invention, for example, an ion-based microscope would be equally valid). In the figure, parts corresponding to items in Figure 1 are indicated using the same reference numerals and will not be considered separately here. Added to Figure 1 are, inter alia, the following parts: - 2a: The vacuum port can be opened to introduce / remove items (parts, samples) into / from the vacuum chamber 2. Alternatively, auxiliary devices / modules can be attached, for example. The microscope M may have multiple such ports 2a, if necessary; - 10a, 10b: Schematically depicted lenses / optical elements in the illuminator 6; -12: a voltage source, allowing the specimen holder H, or at least the specimen S, to be biased (levitated) relative to ground, if necessary; -14: Display such as FPD or CRT; - 22a, 22b: A segmented electron detector 22a may be provided, which includes multiple independent detection segments (e.g., quadrants) arranged around a central aperture 22b (allowing the passage of the beam B). Such a detector can be used, for example, to investigate the flux (angular dependence) of the output (secondary or backscattered) electrons emitted from the sample S.

[0052] Thus, the charged particle microscopes M shown in Figures 1 and 2 each include a charged particle optical column O for irradiating a sample with a charged particle beam B, a sample holder H for holding a sample S, and charged particle detectors 22a, 22b, 30, 32, and 34 having an imaging system 200 for generating image signals based on information from the charged particle detectors.

[0053] Turning now to FIG. 3 , there is shown an embodiment of a charged particle microscope M including details of a charged particle detector D and an imaging system 200 as disclosed herein. It is noted that the detector D is typically either the TEM camera 30, STEM camera 32, spectroscopic detector 34, or segmented detector 22 shown in FIGS. 1 or 2, or a general charged particle detector. Similar to FIGS. 1 and 2, the charged particle microscope M includes a detector D including a detector chip 31. Raw data from the detector chip 31 is sent to an input interface 100 of the imaging system 200. The imaging system 200 is configured to generate an image signal based on information from the charged particle detector D.

[0054] In the embodiment described herein, the charged particle detector D is a charged particle camera D arranged to acquire images of the sample. It should be noted that in general, the use of low latency and high latency output interfaces applies equally to charged particle detectors. For simplicity, the term detector is used. Those skilled in the art will understand that the term detector herein explicitly refers to both charged particle cameras (arranged to acquire images) and other types of detectors (arranged to acquire other data).

[0055] As shown in FIG. 3, the imaging processing system 200 generally includes an input interface 100 for receiving data, a first charged particle detector output interface 101 for outputting a first data stream of data associated with the charged particle detector D, and a second charged particle detector output interface 102 for outputting a second data stream of data associated with the charged particle detector D.

[0056] 3, the first charged particle detector output interface 101 is arranged to transfer data to storage 300. The connection from detector D, via imaging system 200, to storage 300 is used to store high quality images from the sample. Here, the configuration of the first data stream is such that data quality and reliability are prioritized, ensuring accurate and reliable data output to storage 300 (i.e., maintaining the high image quality standards for which today's charged particle microscopes are known).

[0057] As defined herein, the imaging system also includes a second charged particle detector output interface 102. The second charged particle detector output interface 102 is arranged to provide a different output compared to the first output interface 101. In particular, the second charged particle detector output interface 102 is arranged to feed back a low latency output to a data processing device 400, which is connected to the microscope M. Thus, a feedback control loop is established that can be used for feedback control applications such as active image-based docking compensation, continuous tilt tomography field correction, or system state metrology.

[0058] The imaging system 200 comprises, in the embodiment shown, a data processing unit 99 arranged to process data, referred to as "raw" data, from the detector chip 31. This processing unit 99 may be part of the detector D itself, and thus the imaging system 200 may also form part of the detector D. Other arrangements are possible.

[0059] After initial processing by processing unit 99, the signal can be split into two different streams.

[0060] One stream is connected to the output interface 101 of the first charged particle detector and includes a storage representation module 201 and a buffer 211. The storage representation module 201 and the buffer 211 are arranged to provide high quality image data from the detector D to the storage 300 with substantially no loss of image information.

[0061] The other stream is connected to the second charged particle detector output interface 102 and includes a low latency representation module 202. The low latency representation module 202 is arranged to process the signals from the detector D (optionally processed by a data processing unit 99) and provide them to the second charged particle output interface 102. They are then forwarded to a feedback data processing unit 400 where further processing may occur to enable real-time feedback to the charged particle microscope M. This allows for low latency feedback to be provided to the charged particle microscope M, which may include stage movements, changes in optics, etc.

[0062] FIG. 4 illustrates a further embodiment of a charged particle microscope M having an imaging system 200 as disclosed herein. Here, the detector D includes a camera chip 31 and a data processing unit 99. The data processing unit 99 is configured to perform rapid "essential" processing, which may include gain correction and electron counting if the detector D is an electronic detector. This processing typically occurs with low latency. The resulting information is sent from the detector D through an output 90 to an input interface 100 of the imaging system 200. The imaging system 200 splits the data into two different display blocks 201 and 202, which can be configured to convert the data to a desired output-specific format. These blocks 201 and 202 may include additional processing steps or data enhancement steps based on other sources, such as a system clock. For example, if a user selects dose fraction storage, the storage representation block 201 can create a dose fraction image, and the low-latency representation block 202 can output an electronic event representation stream (a stream of electronic event positions (x, y, time)) while embedding additional timing information, such as a synchronization timestamp. The storage representation 201 is buffered in block 211 so that no data is lost if the connection to the storage 300 is recently interrupted. The low latency representation 202 is sent without buffering (or at least without significant buffering) so as not to add extra delay.

[0063] This low latency display module 202, in embodiments, can run independently from the previously described storage display module 201. The low latency display module 202 is preferably optimized for low latency, but data reliability is a low priority, meaning that it is acceptable to miss a small portion of the data as long as this can be detected.

[0064] The particular type of detector D of interest here is an electron counting camera. In this case, the electron counting algorithm is the primary algorithm. The type of data on the output data interface 201 is either an image "movie" (called a dose fraction) or a stream of electronic event locations (x, y, time), also called an Electronic Event Representation (EER). Providing EER data on the low-latency output data interface 202 enables low-latency event-based processing in low-dose applications. Under low-dose conditions, low-latency EER data leads to the best possible performance for the use cases described above.

[0065] Returning to FIG. 4 , it is shown that the low latency display module 202 can be connected to a feedback data processor 400, which in the illustrated embodiment is part of the controller / processor 20. It will be clear to those skilled in the art that the feedback data processor 400 can be a separate controller / processor. From here, the controller / processor 20 can provide feedback to the charged particle microscope M (e.g., as shown in FIGS. 1 and 2 ) by modifying one or more settings / parameters of the optical column O, the sample holder H, the imaging system 24, and / or the charged particle detector D (which can be any one of 22 a, 22 b, 30, 32, 34, as shown in FIGS. 1 and 2 ). The feedback data processor 400 and the low latency display module 202 can provide real-time feedback to the charged particle microscope M.

[0066] In summary, a charged particle microscope M has been described incorporating dual data stream output interfaces 101, 102 within an imaging system 200. These interfaces enable the microscope M to acquire and process data from the charged particle detector D in two different ways, leading to increased imaging capabilities and improved flexibility. This is especially true when one data stream is intended for low latency 102, allowing real-time feedback to the microscope M.

Claims

1. 1. A charged particle microscope, comprising: a charged particle optical column for directing the charged particle beam onto the sample; a sample holder for holding a sample; a charged particle camera and an imaging system for generating an image signal based on information from the charged particle camera; the imaging system comprising a first charged particle camera output interface for outputting a first data stream of data associated with the charged particle camera; A charged particle microscope, wherein the imaging system further comprises a second charged particle camera output interface for outputting a second data stream associated with the charged particle camera, the second data stream being arranged differently compared to the first data stream.

2. The charged particle microscope of claim 1 , wherein the second data stream is optimized for low latency output.

3. 2. The charged particle microscope according to claim 1, wherein the second data stream is arranged so that the maximum output delay is 750 ms, in particular 250 ms or less.

4. 4. The charged particle microscope of claim 3, wherein the second data stream is arranged to have a substantially fixed low latency output.

5. 4. The charged particle microscope of claim 3, wherein the second data stream is arranged to have an average output delay of less than 100 ms.

6. 10. The charged particle microscope of claim 1, wherein the charged particle microscope and a second charged particle camera output data interface are connected and arranged to use the image signal from the imaging system to provide real-time feedback to the charged particle microscope.

7. The charged particle microscope of claim 1 , wherein the first data stream is optimized for high reliability.

8. 8. The charged particle microscope of claim 7, wherein the first data stream is optimized for complete data transfer without data loss.

9. The charged particle microscope of claim 1 , wherein the second charged particle camera output interface operates independently of the first charged particle camera output interface.

10. 2. The charged particle microscope of claim 1, wherein the system comprises a data processing unit upstream of the first and second charged particle camera output interfaces, the data processing unit being arranged to process data provided to the second charged particle camera output interface.

11. The charged particle microscope of claim 10 , wherein the charged particle camera includes the data processing unit.

12. The charged particle microscope of claim 1 , wherein the charged particle microscope comprises a feedback data processing device downstream of the second charged particle camera output interface.

13. 13. A method of operating a charged particle microscope according to any one of claims 1 to 12, comprising using the second charged particle camera output interface to provide low latency data.

14. The method of claim 13 , including using the low latency data to control operation of the charged particle microscope.

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