Scanning patterns for scientific instruments

Abstract

Scanning patterns for scientific instruments. The invention relates to a system and method for adjusting a scan pattern of a scientific instrument based on electromagnetic interference. One example charged particle instrument includes a chamber supporting a sample, a column coupled to the chamber, a pump configured to create a vacuum within the chamber, a sensing device configured to detect a measure of a frequency of electromagnetic interference generated via the pump, and a controller including an electronic processor and a memory. The column includes a charged particle source configured to generate a charged particle beam that travels through the column and into the chamber. The charged particle beam is generated from the scanning pattern. The controller is configured to receive a signal from the sensing device indicative of a frequency of electromagnetic interference, and adjust the scan pattern based on the frequency of electromagnetic interference.

Description

Technical Field

[0001] The present disclosure generally relates to systems and methods for adjusting a scan pattern of a scientific instrument based on electromagnetic interference such as electromagnetic interference occurring within a charged particle system. Summary of the Invention

[0002] Scanning scientific instruments such as charged particle systems include components that generate electromagnetic interference, such as molecular pumps. Other sensitive components involved in measuring a sample, such as columns and detection electronics, may be located close to the electromagnetic interference. For example, during scanning of a sample, the electromagnetic interference may cause the scan pattern to shift. Typically, a shield may be provided to block the electromagnetic interference. Alternatively, the sensitive components may be located far from the electromagnetic interference. However, as the size of the instrument decreases, it becomes increasingly difficult to reduce the impact of the electromagnetic interference.

[0003] The embodiments described herein implement an antenna near an electromagnetic interference generating component of a scientific instrument. The antenna is tuned to a frequency approximating the electromagnetic interference. The frequency of the measured electromagnetic interference is provided to a controller that is configured to adjust, for example, the scan pattern of the scientific instrument based on the interference. For example, scanning may be avoided during peaks of the electromagnetic interference.

[0004] In one aspect, a charged particle instrument includes a chamber that supports a sample, a column coupled to the chamber, and a pump configured to create a vacuum within the chamber. The column includes a charged particle source configured to generate a charged particle beam that travels through the column and into the chamber. The charged particle beam is generated according to a scan pattern. The charged particle instrument also includes a sensing device and a controller, the sensing device being configured to detect a measure of the frequency of electromagnetic interference generated via the pump, the controller including an electronic processor and a memory. The controller is configured to receive a signal from the sensing device indicating the frequency of the electromagnetic interference and to adjust the scan pattern based on the frequency of the electromagnetic interference.

[0005] In another aspect, a charged particle instrument includes a chamber that supports a sample and a column coupled to the chamber. The column includes a charged particle source configured to generate a charged particle beam that travels through the column and into the chamber. The charged particle beam is generated according to a scan pattern. The charged particle instrument also includes an antenna and a controller, the antenna being configured to detect the frequency of electromagnetic interference generated by the charged particle instrument, the controller including an electronic processor and a memory. The controller is configured to receive a signal from the antenna indicating the frequency of the electromagnetic interference and to align the starting point of each scan line forming the scan pattern with a zero crossing of the electromagnetic interference.

[0006] In another aspect, a method for adjusting a scan pattern of a charged particle instrument includes receiving, by an electronic processor, a signal from an antenna indicative of a frequency of electromagnetic interference. The electromagnetic interference is generated by a pump configured to create a vacuum in a chamber that supports a sample. The method includes adjusting, by the electronic processor, a scan pattern of a charged particle beam based on the frequency of the electromagnetic interference. The charged particle beam is generated by a charged particle source of a column. The column is coupled to the chamber and the charged particle beam travels through the column to the chamber.

[0007] There is no specific requirement that a system, method, or technology related to a scanning scientific instrument include all of the details characterized herein in order to obtain some of the beneficial effects in accordance with the present disclosure. Accordingly, the specific examples characterized herein are intended as example applications of the described technology and alternative implementations may also be employed. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The features and advantages of the present technology will become more apparent from the following detailed description of example implementations of the present technology in conjunction with the accompanying drawings, in which:

[0009] Figure 1 is a block diagram illustrating an example scientific instrument in accordance with some implementations.

[0010] Figure 2 is an illustration of an example antenna of a scientific instrument coupled to Figure 1 in accordance with some implementations.

[0011] Figure 3 is in accordance with some implementations of Figure 1 a block diagram of a controller of a scientific instrument.

[0012] Figure 4 is a block diagram of a method performed by a controller of Figure 3 in accordance with some implementations.

[0013] Figure 5A is an illustration of an image of a sample and a scan pattern without correction to account for electromagnetic interference.

[0014] Figure 5B is an illustration of an image of a sample and a scan pattern corrected to account for electromagnetic interference.

[0015] While the present technology is susceptible to various modifications and alternative forms, specific implementations have been shown by way of example in the drawings and will be described in detail herein. However, it should be understood that the invention is not intended to be limited to the particular forms disclosed. On the contrary, the invention will cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims. DETAILED DESCRIPTION

[0016] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. In case of conflict, the present document (including definitions) shall prevail. Although methods and systems similar or equivalent to those described herein can be used to practice or test the present disclosure, example methods and systems are described below. The systems, methods, and examples disclosed herein are merely illustrative and not restrictive systems, methods, and examples.

[0017] As used herein, the terms "comprising," "including," "having," "may," "containing," and variations thereof are intended as open transitional phrases, terms, or words that do not preclude the possibility of the existence of additional acts or structures. Unless the context clearly dictates otherwise, the singular forms "a" and "the" include plural references.

[0018] The modifier "about" used in connection with a quantity includes the recited value and has the meaning provided by the context (e.g., it includes at least the degree of error associated with the measurement of a particular quantity). The modifier "about" should also be considered as disclosing a range defined by the absolute values of the two end-points. For example, the expression "about 2 to about 4" also discloses the range "2 to 4". The term "about" can mean plus or minus 10% of the indicated number. For example, "about 10%" can represent a range from 9% to 11%, and "about 1" can refer to 0.9 to 1.1. Other meanings of "about" can be apparent from the context, such as rounding, so that, for example, "about 1" can also refer to 0.5 to 1.4.

[0019] As used herein, the term "or" is intended to mean an inclusive "or" rather than an exclusive "or". That is, unless otherwise specified or clear from the context, "X uses A or B" is intended to mean any natural inclusive permutation. That is, if X uses A, X uses B, or X uses both A and B, then "X uses A or B" is satisfied in any of the foregoing instances. In addition, unless otherwise specified or clear from the context with respect to the singular form, the articles "a" as used in this specification and the drawings shall generally be construed to mean "one or more".

[0020] For the recitation of numerical ranges herein, each intermediate value having the same degree of precision between those numerical ranges is clearly contemplated. For example, for the range from 6 to 9, the values 7 and 8 are contemplated in addition to 6 and 9, and for the range from 6.0 to 7.0, the values 6.0, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9, and 7.0 are clearly contemplated.

[0021] Reference is now made to the accompanying drawings, in which like reference numerals throughout the specification refer to like elements. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure. It will be evident, however, that the systems and methods of the present disclosure may be practiced without one or more of these specific details. In other instances, well-known structures and devices are shown in block diagram form in order to facilitate describing the systems and methods of the present disclosure.

[0022] Figure 1 is a block diagram illustrating a scientific instrument 100 according to some embodiments. The scientific instrument 100 includes a scanning transmission electron microscope (STEM) column 102 coupled to a vacuum chamber 108. The vacuum chamber 108 houses a movable sample holder 110 and can be evacuated using one or more vacuum pumps 190. In an example embodiment, the sample holder 110 is capable of independent movement parallel to the XY coordinate plane and parallel to the Z axis, where the corresponding coordinate system is defined by Figure 1 the XYZ coordinate triple shown in. The sample S to be interrogated using the scientific instrument 100 is mounted in the sample holder 110, as Figure 1 shown.

[0023] In the example shown, the STEM column 102 includes an electron source 112 and two or more electron beam lenses, two of which (the objective lens 106 and the condenser lens 116 (collectively referred to as electron beam lenses)) are shown schematically only in Figure 1 for purposes of illustration. In some examples, a different (other than two) number of such lenses may be used in the STEM column 102. In some embodiments, the objective lens 106 may be an ultra-high resolution (UHR) lens.

[0024] In operation, electron source 112 generates an electron beam 114 that propagates generally along the longitudinal axis 115 of STEM column 102. Electron beam lenses 106 and 116 are operative to generate electric and magnetic fields that affect the electron trajectories in electron beam 114. Control signals 152, 156 generated by electron controller 150 are used to vary the intensity and / or spatial configuration of the fields and impart desired characteristics to electron beam 114. Generally, electron beam lenses 106 and 116, control signals 152 and 156, and other associated components of scientific instrument 100 can be used to perform various operations and support various functions, such as beam focusing, aberration mitigation, aperture truncation, filtering, and the like. In some embodiments, STEM column 102 also includes a deflection unit 118 that can steer electron beam 114 in response to a control signal 154 applied thereto by electron controller 150. Such beam steering can be used to move the focused portion of electron beam 114 along a desired path across sample S, such as, for example, to perform a raster or vector scan thereon. The path of electron beam 114 can hereafter be referred to as a scan pattern.

[0025] Scientific instrument 100 also includes detectors 160, 170, 180 located within vacuum chamber 108 relatively close to sample S. In operation, detectors 160, 170, and 180 generate measurement result streams 162, 172, and 182 that are received by electron controller 150. The specific types of detectors 160, 170, 180 depend on the embodiment of scientific instrument 100 and can generally be selected from a variety of detector types suitable for detecting different types of emissions and / or radiation from sample S in response to electron beam 114. Example types of emissions / radiation that can be generated in this manner include, but are not limited to, X-rays, infrared light, visible light, ultraviolet light, backscattered electrons, secondary electrons, Auger electrons, elastically scattered electrons, unscattered (e.g., zero energy loss) electrons, and inelastically scattered electrons. In various embodiments, different numbers (other than three) of such detectors can be used in scientific instrument 10. In some embodiments, detectors 160, 170, 180 are selected from the group consisting of: a high angle annular dark field detector, a medium angle annular dark field detector, an annular bright field detector, a segmented annular detector, a differential phase contrast detector, and a two-dimensional (e.g., pixelated) diffraction pattern detector. Other detectors capable of detecting various ones of the above types of emissions / radiation can also be used in various additional embodiments.

[0026] Additionally, although scientific instrument 100 includes electron source 112 that generates electron beam 114, the embodiments described herein can be implemented using charged particle instruments that include other types of charged particle sources and charged particle beams. For example, an ion source can generate an ion beam for scanning sample S.

[0027] The exemplary pump 190 is a turbomolecular pump that includes a turbine-shaped rotor that rotates at high speed when driven by an electric motor. The electric motor includes a static magnet and a rotating magnet that generate an electromagnetic field that varies over time at the same frequency as the rotation frequency of the motor, and the electromagnetic field affects the path of the electron beam 114 and / or the detectors 160, 170, 180. Additionally, in some embodiments of the turbomolecular pump, magnetic bearings are used in place of (or in addition to) other types of bearings that may cause further electromagnetic interference.

[0028] In some embodiments, another type of pump may be substituted for the exemplary pump 190. For example, the pump 190 may be a turbopump, a rotary mechanical pump, an oil diffusion pump, etc.

[0029] An antenna 194 (e.g., a sensing device) is coupled to the outer surface of the pump 190. In some cases, as Figure 2 shown, the antenna 194 is mounted, bolted, or otherwise fixed to the outer surface of the pump 190 via a fastener 200. In some cases, the antenna 194 is mounted to a printed circuit board (PCB) 202, and the PCB 202 is mounted to the outer surface of the pump 190. Additionally, in some cases, the antenna 194 may be mounted near the pump 190 without being mounted to the pump 190. For example, the antenna 194 may be mounted at a location near the pump 190 within the instrument 100 and on a support structure within the outer surface of the instrument 100. The antenna 194 senses electromagnetic interference generated by the pump 190 and sends a signal representative of the sensed electromagnetic interference to the electronic controller 150. In some cases, the antenna 194 sends a signal representative of the amplified, sensed electromagnetic interference to the electronic controller 150. The frequency of the electromagnetic interference generated by the pump 190 may be between 1000 Hz and 2000 Hz (e.g., 1500 Hz).

[0030] Although Figure 1 the scientific instrument 10 is illustrated as a STEM instrument, the scientific instrument 10 may be or may include one or more different types of optical microscopes and / or charged particle microscopes, such as but not limited to a scanning electron microscope (SEM), STEM, a transmission electron microscope (TEM), a charged particle microscope (CPM), a cryo-compatible microscope, a focused ion beam (FIB) microscope, a dual-beam microscope system, or a combination thereof.

[0031] Figure 3A block diagram of the electronic controller 150 is illustrated. The electronic controller 150 includes an electronic processor 300, a memory 302, an input / output (I / O) interface 304, and so on. However, it should be understood that the electronic controller 150 may have more or fewer components. The electronic controller 150 is suitable for applications and settings and may include, for example, multiple electronic processors, multiple I / O interfaces, multiple data storage devices, or combinations thereof. In some specific embodiments, some or all of the components included in the electronic controller 150 may be attached to one or more motherboards and enclosed in a housing (e.g., including plastic, metal, and / or other materials). In some specific embodiments, some of these components may be fabricated onto a single system-on-chip, i.e., SoC (e.g., the SoC may include one or more processing devices and one or more storage devices).

[0032] As used herein, the term "processor" or "electronic processor" refers to any device or part of a device that processes electronic data from registers and / or memory to transform that electronic data into electronic data that can be stored in registers and / or memory. The electronic processor 300 may include one or more digital signal processors (DSPs), application-specific integrated circuits (ASICs), central processing units (CPUs), graphics processing units (GPUs), cryptographic processors (specialized processors that execute cryptographic algorithms in hardware), server processors, or any other suitable processing device.

[0033] The memory 302 may include one or more local memory devices or remote memory devices, such as random access memory (RAM) devices (e.g., static RAM (SRAM) devices, magnetic RAM (MRAM) devices, dynamic RAM (DRAM) devices, resistive RAM (RRAM) devices, or conductive-bridge RAM (CBRAM) devices), hard-drive-based memory devices, solid-state memory devices, network drives, cloud drives, or any combination of memory devices. In some specific embodiments, the memory 302 may include a memory that shares a die with the processor. In such embodiments, the memory may be used as a cache memory and may include, for example, embedded dynamic random access memory (eDRAM) or spin-transfer torque magnetic random access memory (STT-MRAM). In some specific embodiments, the memory 302 may include a non-transitory computer-readable medium having instructions thereon that, when executed by one or more processors (e.g., the electronic processor 300), cause the electronic controller 150 to store various applications and data for performing the methods described herein or one or more of the portions described herein.

[0034] The electronic controller 150 is connected to the electron beam lenses 106 and 116, the deflection unit 118, the detectors 160, 170, and 180, and the antenna 194 via the I / O interface 304. The I / O interface 304 may include one or more communication chips, connectors, and / or other hardware and software to manage the communication between the electronic controller 150 and other components. The I / O interface 304 may include interface circuitry for coupling to one or more components using any suitable interface (e.g., Universal Serial Bus (USB) interface, High-Definition Multimedia Interface (HDMI) interface, Controller Area Network (CAN) interface, Serial Peripheral Interface (SPI) interface, Ethernet interface, wireless interface, or any other suitable interface). For example, the RO interface 304 may include circuitry for managing wireless communication for passing data to and from the electronic controller 150. The term “wireless” and its derivatives may be used to describe circuits, devices, systems, methods, techniques, communication channels, etc., that can convey data by using modulated electromagnetic radiation through a non-solid medium. The term does not imply that the associated devices do not contain any wires, although in some particular implementations there may be no wires in the associated devices. The circuitry for managing wireless communication included in the I / O interface 304 may implement any one of a variety of wireless standards or protocols, including but not limited to Institute of Electrical and Electronics Engineers (IEEE) standards, including Wi-Fi (IEEE 802.11 series), IEEE 802.16 standard (e.g., IEEE 802.16-2005 Amendment), Long-Term Evolution (LTE) project, and any amendments, updates, and / or revisions (e.g., Advanced LTE project, Ultra Mobile Broadband (UMB) project (also known as “3GPP2”, etc.). In some particular implementations, the circuitry for managing wireless communication included in the RO interface 304 may operate according to Global System for Mobile Communications (GSM), General Packet Radio Service (GPRS), Universal Mobile Telecommunications System (UMTS), High-Speed Packet Access (HSPA), Evolved HPS (E-HPSA), or LTE network. In some particular implementations, the circuitry for managing wireless communication included in the I / O interface 252 may operate according to enhanced data for GSM Evolution (EDGE), GSM EDGE Radio Access Network (GERAN), Universal Terrestrial Radio Access Network (UTRAN), or Evolved UTRAN (E-UTRAN). In some particular implementations, the circuitry for managing wireless communication included in the I / O interface 304 may operate according to Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Digital Enhanced Cordless Telecommunications (DECT), Evolution-Data Optimized (EV-DO), and its derivatives, and any other wireless protocols designated as 3G, 4G, 5G, and higher generations.In some specific implementations, the I / O interface 304 may include one or more antennas (e.g., one or more antenna arrays) for receiving and / or transmitting for limited communication.

[0035] Figure 4 The block diagram of an example method 400 for controlling the scan pattern of the scientific instrument 100 is illustrated. The method 400 is described herein as being executed by the electronic controller 150. However, it should be understood that the method 400 (or portions thereof) may be executed by one or more electronic controllers 150 located within the instrument 100, separate from the instrument 100, remote from the instrument 100, or a combination of both.

[0036] At step 402, the electronic controller 150 receives a signal from the antenna 194 indicating the frequency of the electromagnetic interference. For example, the antenna 194 detects the electromagnetic interference generated by the pump 190. The antenna 194 sends a signal representing the sensed electromagnetic interference to the electronic controller 150.

[0037] At step 404, the electronic controller 150 adjusts the scan pattern performed via the instrument 100 based on the frequency of the electromagnetic interference. For example, referring to Figure 5A , the sample S is scanned using multiple scan lines 500. The scan lines 500 form a scan pattern and include an acquisition portion 510 and a retrace portion 512. However, the electromagnetic interference 502 affects the multiple scan lines 500, resulting in the deformation of the imaged sample 504.

[0038] Therefore, in one specific implementation, to adjust the scan pattern, the electronic controller 150 aligns the starting point of each of the multiple scan lines 500 with the zero crossing point 516 of the electromagnetic interference 502, as shown in Figure 5B . The alignment of the scan lines 500 with the zero crossing point 516 can be achieved by inserting a delay period 514 after the retrace portion 512 of the scan lines 500. By aligning the scan lines 500 with the zero crossing point 516, the influence of the electromagnetic interference 502 is reduced, and the imaged sample 506 is substantially similar to the sample S.

[0039] In another specific implementation, to adjust the scan pattern, the electronic controller 150 adjusts the dwell time of the electron beam 114. The dwell time is the amount of time the electron beam 114 stays on each pixel of the sample S during the acquisition of the image of the sample S. For example, multiplying the dwell time by the number of pixels in one scan line and adding the retrace time provides the scan time for a single scan line.

[0040] In one example, the electron beam 114 stays at each position for 200 ns and the scan time is about 200 μs to 400 μs per scan line. At an electromagnetic interference frequency of 1500 Hz, the resulting scan line time is about 667 μs per line. Thus, all the time between 267 μs and 467 μs is lost, and about half of the sample exposure time is not used. Further, the time to reposition the electron beam to the start of the next scan line also takes, for example, dozens of μs, which further increases the time loss.

[0041] To account for this idle period, the per-position line time can be calculated and adjusted based on the frequency of the electromagnetic interference to maximize the effective exposure time per scan line. For example, when the frequency of the electromagnetic frequency is 1500 Hz, the line time can be set within a synchronization period of 667 μs. For example, for 960 positions per line and a 10 μs flyback overhead, the per-position dwell time is set to (667 - 10) μs / 960 = 684 ns. For 1920 positions per line, the per-position line time is set to (667 - 10) μs / 1920 = 342 ns. The per-position line time can be further rounded to the timing granularity of the electronic controller 150 and the deflection unit 118, such as rounding down to the nearest 25 ns value (e.g., 675 ns and 325 ns).

[0042] Although the examples described herein are mainly directed to electromagnetic interference generated by a vacuum pump in a scanning electron microscope, the effects of electromagnetic interference generated by other components can also be mitigated. For example, a motor that moves the sample holder 110 may generate electromagnetic interference that affects the accuracy of the scan results. Thus, an antenna 194 (or an antenna other than antenna 194) can be located on the sample holder 110. Also, a DC / DC converter or other electronics within the scientific instrument 100 may generate electromagnetic interference. The frequency of the electromagnetic interference generated by such components may be different from the frequency of the electromagnetic interference generated by the pump 190. For example, a DC / DC converter may generate electromagnetic interference with a frequency between 100 kHz and 200 kHz.

[0043] In addition, although the examples described herein mainly relate to accounting for electromagnetic interference, in some cases, the effects of mechanical vibrations within the scientific instrument 10 can also be or alternatively mitigated. For example, instead of the antenna 194, a vibration sensor can be provided, and the vibration sensor is configured to detect vibrations caused by moving and / or rotating components attached to the STEM column 102. As a specific implementation of detecting vibrations, the vibration sensor is configured as a motion-sensitive (MEMS) sensor. The electronic controller 150 receives signals from the MEMS sensor and determines the frequency of the mechanical vibration based on the signals from the MEMS sensor.

[0044] Accordingly, the specific embodiments described herein provide a system, method, computing device, storage device, and computer-readable medium for controlling a scan pattern of a scientific instrument based on electromagnetic interference. The specific embodiments described herein improve the accuracy of scanning a sample. Accordingly, the specific embodiments disclosed herein improve scanning scientific instruments.

[0045] As described above in the detailed description, reference is made to the accompanying drawings, which form a part of the detailed description, wherein like reference numerals always designate like parts, and the practicable specific embodiments are illustrated by way of example in the drawings. It should be understood that other specific embodiments may be utilized and structural or logical changes may be made without departing from the scope of the present disclosure. Accordingly, the detailed description set forth above should not be construed in a limiting sense.

[0046] The various operations may be described sequentially in a manner that is most helpful in understanding the disclosed subject matter. However, the described order should be construed as implying that these operations necessarily depend on the order. Specifically, these operations may not be performed in the order presented. The described operations may be performed in a different order than the described specific embodiments. Various additional operations may be performed, and / or the described operations may be omitted in additional specific embodiments.

[0047] Clause

[0048] The following clauses disclose specific embodiments of the present disclosure:

[0049] Clause 1. A charged particle instrument, the charged particle instrument comprising: a chamber for supporting a sample; a column coupled to the chamber, the column including a charged particle source configured to generate a beam of charged particles that travels through the column and into the chamber, wherein the beam of charged particles is generated according to a scan pattern; a pump configured to form a vacuum in the chamber; a sensing device configured to detect a measure of the frequency of electromagnetic interference generated via the pump; and a controller including an electronic processor and a memory, the controller being configured to: receive a signal from the sensing device indicating the frequency of the electromagnetic interference, and adjust the scan pattern based on the frequency of the electromagnetic interference.

[0050] Clause 2. The charged particle instrument according to Clause 1, wherein the frequency of the electromagnetic interference is between about 1000 Hz and 2000 Hz.

[0051] Clause 3. The charged particle instrument according to Clause 2, wherein the frequency of the electromagnetic interference is about 1500 Hz.

[0052] Clause 4. The charged particle instrument according to any one of Clauses 1 to 3, wherein the pump includes one or more magnets that generate the electromagnetic interference.

[0053] Clause 5. The charged particle instrument according to any one of Clauses 1 to 4, wherein adjusting the scan pattern includes aligning the starting point of each scan line forming the scan pattern with the zero crossing point of the electromagnetic interference.

[0054] Clause 6. The charged particle instrument according to any one of Clauses 1 to 5, wherein adjusting the scan pattern includes inserting a delay period into each scan line forming the scan pattern based on the frequency of the electromagnetic interference.

[0055] Clause 7. The charged particle instrument according to any one of Clauses 1 to 6, wherein the sensing device is configured to amplify the frequency of the electromagnetic interference to generate the signal.

[0056] Clause 8. The charged particle instrument according to any one of Clauses 1 to 7, wherein the sensing device is mounted on a printed circuit board, and the printed circuit board is mounted on the surface of the pump.

[0057] Clause 9. The charged particle instrument according to any one of Clauses 1 to 8, wherein adjusting the scan pattern includes adjusting the line time of the scan pattern.

[0058] Clause 10. A charged particle instrument, the charged particle instrument comprising: a chamber for supporting a sample; a column coupled to the chamber, the column including a charged particle source configured to generate a beam of charged particles that travels through the column and into the chamber, wherein the beam of charged particles is generated according to a scan pattern; an antenna configured to detect the frequency of electromagnetic interference generated by the charged particle instrument; and a controller including an electronic processor and a memory, the controller being configured to: receive a signal from the antenna indicating the frequency of the electromagnetic interference, and align the starting point of each scan line forming the scan pattern with the zero crossing point of the electromagnetic interference.

[0059] Clause 11. The charged particle instrument according to Clause 10, wherein the frequency of the electromagnetic interference is greater than 1000 Hz.

[0060] Clause 12. The charged particle instrument according to any one of Clauses 10 to 11, wherein aligning the starting point of each scan line with the zero crossing point of the electromagnetic interference includes inserting a delay period into each scan line forming the scan pattern based on the frequency of the electromagnetic interference.

[0061] Clause 13. The charged particle instrument according to any one of Clauses 10 to 12, wherein the antenna is configured to amplify the frequency of the electromagnetic interference to generate the signal.

[0062] Clause 14. The charged particle instrument according to any one of Clauses 10 to 13, wherein the controller is further configured to adjust the dwell time of the scan pattern based on the frequency of the electromagnetic interference.

[0063] Clause 15. A method for adjusting a scan pattern of a charged particle instrument, the method comprising: receiving, by an electronic processor, a signal from an antenna indicating a frequency of electromagnetic interference, wherein the electromagnetic interference is generated by a pump configured to form a vacuum in a chamber supporting a sample; and adjusting, by the electronic processor, a scan pattern of a charged particle beam based on the frequency of the electromagnetic interference, wherein the charged particle beam is generated by a charged particle source of a column, wherein the column is coupled to the chamber, and wherein the charged particle beam travels through the column to the chamber.

[0064] Clause 16. The method according to Clause 15, wherein the frequency of the electromagnetic interference is between about 1000 Hz and 2000 Hz.

[0065] Clause 17. The method according to any one of Clauses 15 to 16, wherein adjusting the scan pattern comprises aligning, by the electronic processor, a starting point of each scan line forming the scan pattern with a zero crossing of the electromagnetic interference.

[0066] Clause 18. The method according to any one of Clauses 15 to 17, wherein adjusting the scan pattern comprises inserting, by the electronic processor, a delay period into each scan line forming the scan pattern based on the frequency of the electromagnetic interference.

[0067] Clause 19. The method according to any one of Clauses 15 to 18, the method further comprising generating the signal by amplifying the frequency of the electromagnetic interference with the antenna.

[0068] Clause 20. The method according to any one of Clauses 15 to 19, wherein adjusting the scan pattern comprises adjusting, by the electronic processor, the dwell time of the scan pattern.

Claims

1. A charged particle instrument, comprising: a chamber to support the specimen; a column coupled to the chamber, the column comprising a charged particle source configured to generate a charged particle beam that travels through the column and into the chamber, wherein the charged particle beam is generated according to a scan pattern; a pump configured to create a vacuum within the chamber; a sensing device configured to detect a measure of the frequency of electromagnetic interference generated via the pump; and A controller comprising an electronic processor and a memory, the controller being configured to: receiving a signal from the sensing device indicative of the frequency of the electromagnetic interference, and The scanning pattern is adjusted based on the frequency of the electromagnetic interference.

2. The charged particle instrument according to claim 1, wherein: The frequency of the electromagnetic interference is between about 1000 Hz and 2000 Hz.

3. The charged particle instrument according to claim 2, wherein: The frequency of the electromagnetic interference is about 1500 Hz.

4. The charged particle instrument according to claim 1, wherein: The pump comprises one or more magnets that generate the electromagnetic interference.

5. The charged particle instrument according to claim 1, wherein: Adjusting the scanning pattern includes aligning a starting point of each scanning line forming the scanning pattern with a zero-crossing point of the electromagnetic interference.

6. The charged particle instrument according to claim 1, wherein: Adjusting the scan pattern includes inserting a delay period into each scan line forming the scan pattern based on the frequency of the electromagnetic interference.

7. The charged particle instrument of claim 1, wherein: The sensing device is configured to amplify the frequency of the electromagnetic interference to generate the signal.

8. The charged particle instrument of claim 1, wherein: The sensing device is mounted on a printed circuit board which is mounted to a surface of the pump.

9. The charged particle instrument of claim 1, wherein: Adjusting the scan pattern includes adjusting a line time of the scan pattern.

10. A charged particle instrument, comprising: a chamber to support the specimen; a column coupled to the chamber, the column comprising a charged particle source configured to generate a charged particle beam that travels through the column and into the chamber, wherein the charged particle beam is generated according to a scan pattern; an antenna configured to detect frequencies of electromagnetic interference generated by the charged particle instrument; and A controller comprising an electronic processor and a memory, the controller being configured to: receiving a signal from the antenna indicative of the frequency of the electromagnetic interference, and The starting point of each scanning line forming the scanning pattern is aligned with the zero-crossing point of the electromagnetic interference.

11. The charged particle instrument according to claim 10, wherein: The frequency of the electromagnetic interference is greater than 1000 Hz.

12. The charged particle instrument of claim 10, wherein: Aligning a starting point of each scan line with a zero-crossing point of the electromagnetic interference includes inserting a delay period into each scan line forming the scan pattern based on the frequency of the electromagnetic interference.

13. The charged particle instrument of claim 10, wherein: The antenna is configured to amplify the frequency of the electromagnetic interference to generate the signal.

14. The charged particle instrument of claim 10, wherein: The controller is further configured to adjust a dwell time of the scanning pattern based on the frequency of the electromagnetic interference.

15. A method for adjusting a scan pattern of a charged particle instrument, the method comprising: receiving, with an electronic processor, a signal from the antenna indicative of a frequency of an electromagnetic interference, wherein the electromagnetic interference is generated by a pump configured to create a vacuum within a chamber supporting a sample, and A scanning pattern of a charged particle beam is adjusted with the electronic processor based on the frequency of the electromagnetic interference, wherein the charged particle beam is generated by a charged particle source of a column, wherein the column is coupled to the chamber, and wherein the charged particle beam travels through the column to the chamber.

16. The method according to claim 15, wherein: The frequency of the electromagnetic interference is between about 1000 Hz and 2000 Hz.

17. The method according to claim 15, wherein: Adjusting the scanning pattern includes aligning, using the electronic processor, a starting point of each scanning line forming the scanning pattern with a zero crossing point of the electromagnetic interference.

18. The method according to claim 15, wherein: Adjusting the scan pattern includes inserting, with the electronic processor, a delay period into each scan line forming the scan pattern based on the frequency of the electromagnetic interference.

19. The method of claim 15, further comprising generating the signal by amplifying the frequency of the electromagnetic interference with the antenna.

20. The method according to claim 15, wherein: Adjusting the scan pattern includes adjusting, with the electronic processor, a dwell time of the scan pattern.

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