Disturbance compensation for charged particle beam devices

Abstract

This relates to disturbance compensation for charged particle beam devices. A charged particle beam device for repair work, for example, is subjected to a disturbance, and the sensor output of one or more sensors is used to compensate for the disturbance during execution of a manipulation mode, for example, to repair a defect on a lithography mask.

Description

[Technical Field]

[0001] Priority This application claims priority from German Patent Application No. 102022124686.8 (filed September 26, 2022), the entire contents of which are incorporated herein by reference.

[0002] Various embodiments of the present disclosure relate generally to charged particle beam devices and methods of operating charged particle beam devices, and more particularly to compensating for disturbances during operation of charged particle beam devices. [Background technology]

[0003] For example, charged particle beam devices can be used for microscopic inspection or manipulation of semiconductor structures. Charged particles that can be used in charged particle beam devices include electrons, positrons, muons, and ions. Examples of charged particle beam devices include scanning electron microscopes (SEMs), focused ion beam (FIB) devices, and SEMs that include multiple beams, sometimes called multi-SEMs.

[0004] For example, Japanese Patent Application No. 2004-079334 discloses an electron beam device, such as an electron microscope or electron beam lithography device, equipped with a semiconductor electron beam detector for detecting electron beams. A plurality of electron beam sensors are arranged on opposite sides of a mounting substrate, thereby enabling easy replacement of the semiconductor electron beam detector.

[0005] Particle microscopes can be used to record images of objects. In this way, for example, the structure of a surface can be analyzed (inspection mode). Also, samples can be modified, for example, by removing or depositing material (manipulation mode). For example, charged particle beam devices can be used to modify / manipulate lithography masks. In that case, the charged particle beam device may be called a repair device. An example of such a repair device is disclosed in U.S. Patent Application Publication No. 20200912914, the disclosure of which is incorporated herein by reference.

[0006] US Patent Application Publication No. 2018 / 0277361 discloses a method for depositing material on a sample, comprising directing a charged particle beam at a substrate to induce deposition from a precursor gas of a protective layer above a region of interest. The protective layer can be a complex mixture of materials having an array of spots substantially coinciding with the array of spots on the substrate.

[0007] External disturbances often cause irregularities in the operation of charged particle beam devices. For example, external disturbances from fluctuating temperature, pressure, vibrations, etc. often affect the beam positioning of the particle beam of the charged particle beam device relative to the sample stage.

[0008] Since measurement of the beam offset of a charged particle beam during operation in inspection or manipulation mode is not possible or is only possible to a limited extent, closed-loop control for compensating for the beam offset is not always possible. Forward compensation of individual disturbances is known in the art and will be described below.

[0009] For example, Japanese Patent Application No. 2003173755 discloses a charged particle beam device including an active magnetic field source configured to cancel disturbances caused by external magnetic fields. However, it has been observed that the technique disclosed in Japanese Patent Application No. 2003173755 only provides insufficient compensation for the placement offset.

[0010] U.S. Patent No. 3,842,272 discloses a scanning charged particle microscope system. A beam scans a sample in a predetermined pattern. Spurious external electric and magnetic fields can be compensated for by applying a beam correction signal to the beam scanning means. Again, the use of techniques such as those disclosed in U.S. Patent No. 3,842,272 provides insufficient compensation for the position offsets caused by these spurious external electric and magnetic fields.

[0011] No. 6,043,490 discloses a charged particle beam device that includes means for separately detecting the x and y components of mechanical vibrations and means for correcting the x and y scan signals to eliminate the effects of the mechanical vibrations. The technique of U.S. Pat. No. 6,043,590 provides only limited ability to compensate for beam placement offsets in a charged particle beam device due to disturbances.

[0012] U.S. Patent No. 9,601,310 discloses a charged particle microscope including a barometric pressure sensor. A control procedure is used to compensate for relative position errors between the charged particle beam and the specimen holder based on a sensor signal from the barometric pressure sensor. The technique disclosed in U.S. Patent No. 9,601,310 only achieves limited accuracy in compensating for position offsets due to external disturbances.

[0013] US Pat. No. 4,698,503 discloses a refocusing apparatus for use in a transmission electron microscope operable to respond to electron beam sensor output signals at discrete illumination angles. Summary of the Invention

[0014] Therefore, there is a need for advanced techniques to compensate for beam offsets of a beam of a charged particle beam device on a sample stage caused by multiple disturbances. Therefore, as the demand for resolution increases, there is a need for advanced techniques to compensate for beam aberrations of beam blur of a beam of a charged particle beam device caused by multiple disturbances.

[0015] This need is met by the features of the independent claims. The features of the dependent claims define embodiments.

[0016] According to an embodiment, a charged particle beam device includes a beam source, a beam deflection unit, and a sample stage.

[0017] The charged particle beam device, in some embodiments, implements a charged particle beam repair device, in which case the charged particle beam repair device further includes a precursor gas source. The precursor gas source includes a gas supply, a supply valve, and a supply nozzle located near the sample stage. In some cases, the charged particle beam repair device can include multiple precursor gas sources to supply different types of precursor gas.

[0018] The beam deflection unit is configured to deflect a beam of charged particles, for example electrons or ions, for positioning the beam on the sample stage.

[0019] The charged particle beam repair device includes a plurality of sensors configured to measure a plurality of disturbances of a plurality of physical quantities, each of which affects a beam offset of the beam on the sample stage.

[0020] The charged particle beam repair device also includes at least one control unit, such as a microprocessor or processor, configured to execute program code loaded from the memory. Embedded electronics can also be used. A field programmable gate array (FPGA) can also be used to implement the control unit.

[0021] At least one control unit has various tasks of beam control and process control.

[0022] The at least one control unit may also process sensor outputs provided by the plurality of sensors to determine one or more compensation signals for combating beam offset.

[0023] In some embodiments, the at least one control unit is also configured to provide control signals to the beam source, the beam deflection unit, and the precursor gas source for performing electron beam induced manipulation of a sample attached to the sample stage, for example when a manipulation mode is implemented to perform a repair operation on the sample.

[0024] The at least one control unit is configured to supply one or more compensation signals to at least one of one or more compensation modules arranged in or around the beam source, the beam deflection unit, the sample stage, or the charged particle beam repair device, for example during this electron beam induced manipulation or when operating in imaging mode.

[0025] Such techniques allow for the reduction or complete compensation of disturbances during operation of the charged particle beam device, for example, when operating in imaging or manipulation mode. For example, one or more repair operations can be performed on a semiconductor mask during manipulation mode. By reducing or compensating for disturbances while the manipulation is being performed, damage to the mask can be avoided.

[0026] A method for manipulating a sample attached to a sample stage of a charged particle beam repair device is disclosed. The charged particle beam repair device includes a beam source, a beam deflection unit, a precursor gas source, and a sample stage. The beam deflection unit is configured to deflect a beam of charged particles emanating from the beam source to position the beam on the sample stage. The method includes acquiring sensor outputs of a plurality of sensors of the charged particle beam repair device. The plurality of sensors measure a plurality of disturbances of a plurality of physical quantities, each of which affects a beam offset of the beam on the sample stage. The method also includes determining one or more compensation signals for suppressing the beam offset based on the sensor outputs of the plurality of sensors. The method also includes providing control signals to the beam source, the beam deflection unit, and the precursor gas source to perform electron beam-induced manipulation of the sample. The method further includes providing the one or more compensation signals to at least one of the beam source, the beam deflection unit, the sample stage, or one or more compensation modules during the electron beam-induced manipulation.

[0027] A computer program or computer program product or computer readable storage medium includes program code that is loadable and executable by at least one processor, the at least one processor being configured, when loaded and executed, to perform the method of manipulation of a sample as described above.

[0028] In some embodiments, the charged particle beam device includes a beam source, a beam deflection unit, and a sample stage. The beam deflection unit is configured to deflect a beam emanating from the beam source to position the beam on the sample stage. The charged particle beam device includes a plurality of sensors configured to measure a plurality of disturbances of a plurality of physical quantities, each disturbance affecting a beam offset of the beam on the sample stage. The at least one control unit is configured to determine, based on sensor outputs of the plurality of sensors, metadata indicative of one or more compensation actions to suppress beam offset in imaging data acquired by the charged particle beam repair device operating in an imaging mode. The metadata can be stored in association with the image data.

[0029] A method for post-processing image data acquired by a charged particle beam device is disclosed. The charged particle beam device includes a beam source, a beam deflection unit, and a sample stage. The beam deflection unit is configured to deflect a beam emanating from the beam source to position the beam on the sample stage. The method includes acquiring sensor outputs of a plurality of sensors of the charged particle beam device. The plurality of sensors measure a plurality of disturbances of a plurality of physical quantities, each disturbance affecting a beam offset of the beam on the sample stage. The method also includes determining metadata based on the sensor outputs of the plurality of sensors. The metadata indicates one or more compensation operations for suppressing the beam offset in the image data. The image data is acquired by the charged particle beam device when operating in an imaging mode. The method also includes post-processing the image data based on the metadata and in accordance with the one or more compensation operations.

[0030] A computer program or computer program product or computer-readable storage medium includes program code that is loadable and executable by at least one processor, the at least one processor being configured to, when loaded and executed, perform the method for post-processing image data as described above.

[0031] Such techniques allow for reduced or complete compensation of disturbances in the post-processing of imaging data acquired by a charged particle beam device, for example when operating in imaging mode.

[0032] It is to be understood that the features mentioned above and those described below may be used not only in the respective combinations shown, but also in other combinations or separately without departing from the scope of the invention. [Brief explanation of the drawings]

[0033] [Figure 1] 1A-1C are diagrams illustrating schematic placement offsets of charged particle beams, according to various embodiments. [Figure 2] 2A-2C are diagrams illustrating schematic diagrams of compensation for the placement offset of FIG. 1, according to various embodiments. [Figure 3] 2A-2C are diagrams illustrating schematic diagrams of compensation for the placement offset of FIG. 1, according to various embodiments. [Figure 4] 1A-1C are diagrams illustrating schematic representations of charged particle beam focus offsets and respective compensations, according to various embodiments; [Figure 5] 1A-1C are diagrams illustrating schematic illustrations of focus offsets and respective compensations according to various embodiments. [Figure 6] 1A and 1B are schematic diagrams illustrating charged particle beam devices according to various embodiments. [Figure 7] 1 is a flowchart illustrating a method according to various embodiments. [Figure 8] 1 is a flowchart illustrating a method according to various embodiments. [Figure 9]1A-1C are diagrams illustrating schematic time series data of sensor outputs and characteristic fingerprints of disturbances of the respective physical quantities, according to various embodiments. [Figure 10] 1 is a flowchart illustrating a method according to various embodiments. [Figure 11] 1A-1C are schematic diagrams illustrating embodiments of charged particle beam devices with repair devices, according to various embodiments. [Figure 12] 12A-12C are schematic diagrams illustrating sensor placement relative to the repair device of FIG. 11, according to various embodiments. [Figure 13] 12A-12C are diagrams illustrating schematic sensor placements in the repair device according to FIG. 11, according to various embodiments. [Figure 14] 1A-1C are diagrams that schematically illustrate defects in lithography masks, according to various embodiments. [Figure 15] 1A-1C are diagrams that schematically illustrate repaired defects in a lithography mask, according to various embodiments. [Figure 16] 1A and 1B are schematic diagrams illustrating charged particle beam devices according to various embodiments. DETAILED DESCRIPTION OF THE INVENTION

[0034] Some embodiments of the present disclosure generally provide multiple circuits or other electronic devices. All references to these circuits and other electrical devices and the functions provided by each are not intended to be limited to encompass only those shown and described herein. While various disclosed circuits and other electrical devices may be labeled with specific labels, such labels are not intended to limit the scope of operation of the circuits and other electrical devices. Such circuits and other electrical devices may be combined and / or separated in any manner based on the particular type of electrical implementation desired. It is recognized that any circuit or electrical device disclosed herein can include any number of microcontrollers, graphics processor units (GPUs), integrated circuits, memory devices (e.g., flash, random access memory (RAM), read-only memory (ROM), electrically programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or other suitable variations thereof), and software that cooperate with each other to perform the operations disclosed herein. Furthermore, any one or more of the electrical devices can be configured to execute program code embodied in a non-transitory computer-readable medium that is programmed to perform any number of functions as disclosed.

[0035]

[0023] In the following, embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be understood that the following description of the embodiments should not be construed in a limiting sense. The scope of the present invention is not intended to be limited by the embodiments described below or in the drawings, which should be construed as examples only.

[0036] The drawings should be considered as schematic representations, and the elements shown in the figures are not necessarily drawn to scale. Rather, the various elements are represented so that their function and general purpose will be apparent to those skilled in the art. Any connections or couplings between functional blocks, devices, components, or other physical or functional units shown in the drawings or described herein may be implemented by indirect connections or couplings. Couplings between components may also be established via wireless connections. The functional blocks may be implemented in hardware, firmware, software, or a combination thereof.

[0037] The following disclosure relates to particle beam devices. In particular, the disclosure relates to charged particle beam devices. Charged particles usable by such devices are electrons and / or ions. In other embodiments, non-charged particles, such as photons, may be used. However, the following disclosure relates to charged particle beam devices for illustrative purposes.

[0038] Examples of charged particle beam devices include SEMs, aberration-corrected SEMs (typically with a relatively large detection aperture so that the depth of focus range is small), FIB devices, multi-SEMs, cross-beam devices including SEM and FIB optics, and SEMs or FIBs with precursor gas sources for repair / circuit modification operations in manipulation mode (also referred to as repair devices, as described in more detail below in connection with Figure 11).

[0039] Repair operations relate to the modification of structures on semiconductor masks used for lithography. Repair operations are performed using electron-beam-induced manipulation of a sample based on the interaction of one or more precursor gases with an electron beam. Alternatively or additionally, ions can be used in the repair or modification operations. In some embodiments, repair operations are employed to modify electrical circuits on semiconductor devices, e.g., wafers. In particular, charged particles, e.g., electrons or ions such as helium or neon, are used to modify such structures. For example, a charged particle beam interacts with one or more precursor gases selectively delivered to a sample stage. One or more components of the one or more precursor gases are then deposited on the structures. In embodiments, material can also be removed using, for example, a focused ion beam. Repair operations are generally associated with the manipulation mode of a charged particle beam device in which a sample / specimen is manipulated. Repair operations essentially involve the execution of control of a beam source, a beam deflection unit, and a precursor gas source using their respective control signals to perform electron-beam-induced manipulation of the sample. Examples of manipulation include electron-beam induced deposition (EBID) and electron-beam induced etching (EBIE). Exemplary repair operations are described in more detail below in connection with FIGS. 14 and 15.

[0040] The various techniques disclosed herein are based on the realization that the demands on precision of operation of charged particle beam devices increase with the continuing miniaturization of the typical dimensions of the structures to be inspected or altered (the structures are typically characterized by a critical dimension that indicates the minimum feature size that needs to be addressed). For example, a typical critical dimension may be less than 7 nanometers, or even less than 5 nanometers.

[0041] Below, techniques are disclosed that facilitate operation of charged particle beam devices in high precision inspection and / or manipulation modes so that structures having small critical dimensions can be handled, for example, critical dimensions of less than 7 nanometers or even less than 5 nanometers.

[0042] This is achieved by providing one or more compensation signals that compensate for the beam offset. Details regarding such beam offset and associated compensation are disclosed in connection with the following figures.

[0043] 1 schematically illustrates a charged particle beam 91 of a charged particle beam device, such as an electron beam or an ion beam of, for example, helium ions. The charged particle beam 91 is focused by the optics of a beam deflection unit 112 to a specific position 85 on a sample stage 113 of the charged particle beam device. However, due to one or more disturbances, a beam offset occurs, specifically a position offset 81 that shifts the charged particle beam 91 toward another position 86 on the sample stage 113. This is a shift in the x-direction. Similarly, a shift in the y-direction may also occur. In addition to such a position offset 81, the disturbances may also introduce other aberrations that lead to reduced accuracy.

[0044] In principle, the accuracy of a charged particle beam device depends on both the resolution of the charged particle beam and the placement of the charged particle beam on the sample stage. Typical resolution is defined by a beam diameter typically in the 3-5 nanometer range or even smaller (less than 1 nm for aberration-corrected instruments). Meanwhile, the placement of the charged particle beam on the sample stage is typically affected by multiple disturbances of multiple physical quantities that affect beam offset, including the placement offset discussed above in connection with Figure 1. A further type of beam offset is the focus offset, discussed below in connection with Figures 4 and 5.

[0045] Such positioning offsets, which reduce the accuracy of beam positioning, are particularly critical for the operation of charged particle beam devices, since the specification requirements imposed on the accuracy of the positioning of the charged particle beam on the sample stage are often much higher than the specification requirements imposed on the beam diameter / resolution. One reason for this is that, for example, in connection with the manipulation mode, certain structures need to be created or modified with an accuracy of less than 3 nanometers, optionally less than 2 nanometers, or even less than 1 nanometer. Furthermore, positioning offsets when operating in inspection mode can reduce the overall image quality of the resulting image, while positioning offsets due to disturbances during manipulation can cause damage to expensive semiconductor structures or even lithography masks.

[0046] Accordingly, techniques are disclosed that facilitate compensation for placement offset and focus offset by providing one or more compensation signals when a charged particle beam device is operating in a manipulation mode.

[0047] According to various embodiments, a charged particle beam device includes a plurality of sensors for measuring a plurality of disturbances of a plurality of physical quantities, all of which affect a beam offset of a beam on a sample stage. The charged particle beam device also includes a control unit configured to determine one or more compensation signals for suppressing the beam offset based on sensor outputs of the plurality of sensors. The control unit is configured to provide the one or more compensation signals to at least one of a beam source of the charged particle beam device, a beam deflection unit of the charged particle beam device, the sample stage, or one or more compensation modules.

[0048] In principle, the beam offset may include at least one of a beam position offset (along the X or Y direction in FIG. 1, i.e., along the plane of the sample stage 113) or a beam focus offset (along the Z direction in FIG. 1, perpendicular to the plane of the sample stage 113).

[0049] By considering disturbances arising from multiple physical quantities, a comprehensive compensation of the beam offset is obtained, in particular a more accurate compensation when compared to scenarios known from the prior art in which only individual physical quantities, such as temperature, pressure, vibrations or acoustic vibrations (i.e. sound waves), are considered in isolation. To achieve a more accurate compensation of the beam offset, cross-correlations between different pairs of physical quantities can be taken into account. For example, nonlinear effects due to cross-correlations can be considered.

[0050] In principle, according to an embodiment, various physical quantities are taken into account for compensation, the physical quantities being selected from the group comprising acoustic vibrations, vibrations, pressure, humidity, laminar flow, turbulent flow, differential quantities, temperature, rate of change (i.e. defining the rate of change over time), differential quantities, vector quantities (e.g. electric field, magnetic field) or scalar quantities (e.g. temperature, pressure).

[0051] Differential quantities represent spatial gradients of the respective quantities, such as temperature or pressure gradients. Often, such differential quantities can impose stresses or strains on materials, thereby creating disturbances. Further examples include laminar or turbulent flow.

[0052] Acoustic vibrations, in some embodiments, include external acoustic vibrations arising from, for example, objects being moved around the charged particle beam device. Passive damping systems are known in the prior art that attempt to isolate the charged particle beam device from its surroundings. However, such passive damping typically cannot absorb all acoustic vibrations, and therefore active compensation as described herein may be desirable. Acoustic vibrations may have residual components from moving parts within the charged particle beam device. Such internal components may be excited by external acoustic vibrations via mechanical contact, e.g., via the floor or support wires, or via sound.

[0053] In some embodiments, pressure varies as a function of time. Pressure fluctuations can occur on relatively long time scales, for example, when compared to acoustic vibrations. Passive compensation by pressure stabilization systems is known. However, such passive compensation has some accuracy limitations. Pressure fluctuations can occur in the coolant or the ambient air. Ambient air pressure fluctuations change the forces applied to the vacuum housing of the charged particle beam device, thereby causing changes in the hardware mechanisms.

[0054] Temperature fluctuations are compensated for to some extent by passive temperature control, for example, using a stabilized temperature bath or an external air conditioning system, according to some embodiments. Active control according to the techniques disclosed herein can be used to more accurately compensate for even small temperature fluctuation disturbances. For example, temperature fluctuations in the coolant are measured using appropriately positioned temperature sensors, according to various embodiments. In further embodiments, the temperature of the coolant is measured. In further embodiments, temperature fluctuations in an electronic control device or measurement device are measured and compensated for. According to embodiments, temperature differences / gradients between two or more components of a charged particle beam device are measured. For example, the temperature gradient between different measurement points in a fluid flow, e.g., in the coolant, is measured and the respective disturbances are compensated for.

[0055] Another physical quantity that can cause disturbances is the electric field. Prior art systems often employ respective shielding. However, while such shielding may be somewhat effective against external electric fields, internally generated electric fields due to, for example, electric or induced currents or charging capacitances cannot be easily shielded using external shielding. Unwanted particle charging inside the column due to the charged particle beam may occur. On the other hand, using the techniques described herein, sensors near the optics, for example, inside the vacuum chamber of the charged particle beam device, are used in some embodiments to measure the electric field and then compensate for such fields. Similar observations apply to magnetic fields.

[0056] As can be seen from the above, some disturbances, such as magnetic or electric fields, directly affect a charged particle beam by deflecting charged particles propagating along the beam. For example, electric or magnetic fields exert forces on electrons or charged ions, deflecting these particles. These are direct disturbances. Disturbances can also indirectly affect a charged particle beam by affecting one or more components of a charged particle beam device. For example, acoustic vibrations cause a position offset in the optics of a beam deflection unit of a charged particle beam device, which in turn causes a beam offset of the beam. Electric or magnetic fields change the analog supply current or voltage of the beam source or the optics of a beam deflection unit of a charged particle beam device, which in turn affects the position offset. These are indirect disturbances. The techniques disclosed herein make it possible to compensate for both direct and indirect disturbances.

[0057] For example, a geometry offset, such as that shown in Figure 1, or more generally, a beam offset, can occur in the imaging mode of a scanning electron microscope. For example, the movement of magnetic materials, such as iron, cobalt, nickel, steel, etc., can change the magnetic field at the location of the charged particle beam. This can occur due to movements around the charged particle beam device, for example, due to elevators, cranes, doors, lifting trucks, moving people, mobile phones, keys, etc.

[0058] Similar considerations apply to focused ion beam devices. Focused ion beams can be used to remove material from a sample in a manipulation mode. If a disturbance occurs that affects the ion beam, material will be removed in unintended areas of the sample. Therefore, using the techniques disclosed herein, the ion beam is stabilized on the sample and on the sample stage, respectively. This helps avoid damage to the sample and allows for greater accuracy in, for example, transmission electron microscope (TEM) sheet preparation or 3D tomography sample inspection.

[0059] Similarly, in the case of a mask repair process in a manipulation operation, structures on a lithography mask are repaired by depositing material and / or locally removing material from the lithography mask using electron or ion beam induced processes. Using the techniques disclosed herein, any beam offset of the electron or ion beam relative to the lithography mask and sample stage, respectively, is reduced to allow for greater precision in the manipulation operation.

[0060] In principle, various options are available for suppressing beam offset according to the disclosed embodiments. According to the embodiments, different options for suppressing beam offset are employed for different root causes of disturbances. For example, different options for suppressing beam offset are employed for direct and indirect disturbances, respectively, as described above. For example, a compensation signal is applied to the optics of the beam deflection unit to steer the beam in an opposite direction compared to the positioning offset. For example, a compensation signal is applied to the focusing optics of the beam deflection unit to change the focal length to suppress the focus offset caused by the respective disturbance. In some embodiments, instead or in addition, the sample stage is controlled to reposition itself to suppress the beam offset. In further embodiments, dedicated compensation is used, such as external coils for applying a magnetic field or field plates for applying an electric field. For example, compensation for DC or slowly changing magnetic fields can be obtained using a Helmholtz coil pair, one coil for each spatial direction. Such a coil pair is positioned outside the housing of the charged particle beam device. According to further embodiments, active cooling or heating is used. For example, a heating or cooling element in thermal contact with the cooling liquid may be provided, allowing active temperature control. In some embodiments, active damping is controlled to suppress vibrations. In some embodiments, pressure is actively controlled. Hereinafter, devices or units that suppress beam offset indirectly, i.e., do not apply a direct force to the charged particle beam by applying a magnetic or electric field or do not shift the sample stage relative to the charged particle beam, will be referred to as compensation modules. Such compensation modules are controlled by respective compensation signals.

[0061] Below, we will mainly discuss techniques related to applying compensation signals to the beam deflection unit and / or the sample stage, and some exemplary options for suppressing beam offset by such means will be described.

[0062] Figure 2 shows an aspect related to compensation of the placement offset 81 of Figure 1. As shown in Figure 2, an additional beam shift 82 that counteracts the placement offset 81 is realized by providing a control signal to the beam deflection unit 112. For example, an additional voltage is applied to the respective electron lens.

[0063] Figure 3 shows a schematic representation of the compensation of the placement offset 81 of Figure 1. In the scenario of Figure 3, a compensation signal is applied to the control motor of the sample stage 113 to cause a stage shift 83 that compensates for the placement offset 81.

[0064] 3 may be particularly useful for closed-loop controlled motorized stages 113. For example, interferometric stages are known that can provide positioning accuracy in the nanometer range.

[0065] Above, we have described a scenario where the geometry offset is affected by multiple disturbances. Instead of or in addition to affecting the geometry offset, the disturbances can affect the focus offset of the charged particle beam. This is shown in Figure 4.

[0066] Figure 4 shows an undisturbed beam 91 in the absence of any disturbances. Also shown are two disturbed beams 93, 94 with respective focus offsets 71, 72. By adding additional defocus to the beams, the focus offsets 71, 72 can be suppressed. The beam deflection unit 112 can be controlled accordingly. A defocus 75 is shown to suppress the focus offset 71, and a further defocus 76 is shown to suppress the focus offset 72. In another scenario, it is also possible to add respective vertical stage shifts 77, 78, as shown in Figure 5.

[0067] According to various embodiments, focus offset compensation is applied to an aberration-corrected SEM. Typically, an aberration-corrected SEM has a relatively large numerical aperture and therefore a shallow depth of focus range. Such an aberration-corrected SEM can be employed for manipulation operations where the thickness of the structure to be manipulated is in the same range as or smaller than the depth of focus range. In such scenarios, focus offset compensation is particularly important for achieving good results in the manipulation operations.

[0068] Various techniques are based on the knowledge that disturbances can occur on different time scales. On the other hand, there can be slowly varying disturbances, such as those caused by DC magnetic fields, temperature, or pressure changes. Typically, such slowly varying disturbances can be compensated for using the techniques disclosed herein, for example, by applying one or more compensation signals to suppress beam offset. Here, the use of compensation by applying additional voltages to the beam optics (see FIGS. 2 or 4) typically results in a shorter response time compared to compensation based on stage shifts (see FIGS. 3 and 5). This is because stage movement typically requires a longer time due to the limited movement speed of the motors. The operation of the charged particle beam device, for example, in the imaging or manipulation mode, does not need to be stopped for such compensation; i.e., compensation can be applied during ongoing operation.

[0069] On the other hand, some disturbances may change on a fast time scale, for example, within a few seconds or in the sub-second range. An example relates to physical quantities such as acoustic or seismic vibrations, for example, resulting from vibrations in a building foundation. A technique that enables determining a predicted component of the beam offset to compensate for such fast disturbances is disclosed below. Alternatively or additionally, in a further embodiment, information about such disturbances is stored, and such information is determined based on sensor outputs, for example, together with imaging data acquired in imaging mode. In other words, according to an embodiment, metadata indicative of one or more compensation actions for suppressing the beam offset in image data acquired by a charged particle beam device operating in imaging mode is determined based on sensor outputs of a plurality of sensors, and then the metadata is stored in association with the image data. Then, after acquisition, the acquired image data is digitally post-processed to compensate for such disturbances based on the metadata.

[0070] In some embodiments, a disturbance is detected that causes an interruption of the operation of the charged particle beam device. For example, the charged particle beam can be blanked. The imaging or manipulation mode is suspended until the disturbance is resolved. Such a scenario is particularly useful during the manipulation mode to avoid damage to the manipulated sample.

[0071] 6 shows a charged particle beam device 100 according to various embodiments. For example, the charged particle beam device 100 can be a charged particle beam repair device. The charged particle beam device 100 includes a vacuum chamber 110. Inside the vacuum chamber 110, a beam source 111, a beam deflection unit 112, and a sample stage 113 are arranged. An integrated control unit 119 controls the beam source 111, the beam deflection unit 112, and the sample stage 113. The control unit 119 can also control further components of the charged particle beam device 100, such as control valves of precursor gas sources (not shown in FIG. 6).

[0072] Also shown are two sensors 121, 122, each for measuring a disturbance of a physical quantity that affects the beam offset of the charged particle beam 90 on the sample stage 113.

[0073] Although two sensors 121, 122 are shown in the scenario of Figure 6, in principle only a single sensor may be used, or more than two sensors may be used.

[0074] In some embodiments, at least one of the sensors is located inside the vacuum chamber 110. Alternatively or additionally, at least one sensor is located outside the vacuum chamber 110.

[0075] For example, sensors measuring the same physical quantity, e.g., temperature, are placed at multiple locations, thereby measuring a differential physical quantity, e.g., a temperature difference or a pressure difference.

[0076] By locating the sensor outside the vacuum chamber, it is possible to measure physical quantities that change slowly as a function of position, such as external electric or magnetic fields, while at the same time avoiding the operation of the sensor affecting the particle beam. In some embodiments, nevertheless, sensors for physical quantities that exhibit, for example, strong position dependence, are located closer to the beam path of the beam 90.

[0077] Also shown is a control unit 130. In some embodiments, the control unit 130 is implemented by a computer. The control unit 130 communicates with the built-in control unit 119 and the sensors 121, 122. While Figure 6 illustrates a scenario in which the control unit 130 communicates directly with the sensors 121, 122, in other embodiments, such communication is via the built-in control unit 119.

[0078] In either case, the control unit 130 obtains sensor signals 161, 162 (i.e., sensor outputs) from the sensors 121, 122. Based thereon, the control unit 130 provides one or more compensation signals 165 to one or more components of the charged particle beam device 100 to compensate for the placement offset.

[0079] Control unit 130 includes a processor 132 coupled to memory 133. Processor 132 also communicates via communication interface 131. The processor loads program code from memory 133 and executes the program code. Execution of the program code causes processor 132 to perform the techniques disclosed herein for compensation of multiple disturbances of multiple physical quantities, each of which affects the beam offset.

[0080] The control unit 130 also includes a human-machine interface (HMI) 134, such as a display, a web interface, a mouse, a keyboard, etc. User input is received via the HMI 134, or information is output via the HMI 134. For example, site-specific disturbance events are obtained from a user via the HMI 134. In some examples, alerts are output to a user via the HMI 134.

[0081] The following describes scenarios involving logic related to beam offset compensation residing in control unit 130, although in other embodiments at least a portion of that logic resides in embedded control unit 119.

[0082] Figure 7 is a flowchart of a method according to various embodiments. Figure 7 illustrates phases of operation of a charged particle beam device, such as the charged particle beam device 100 of Figure 6. The method of Figure 7 can be performed by the control unit 130 and / or the integrated control unit 119.

[0083] Box 6005 corresponds to a calibration phase, in which one or more transfer functions are set between the sensor outputs of multiple sensors that measure disturbances of multiple physical quantities and the compensation signal.

[0084] Such a transfer function therefore links the values ​​of multiple physical quantities (represented by sensor signals 161, 162) to beam offset compensation (represented by compensation signal 165).

[0085] Box 6010 then corresponds to the operation phase. In the operation phase, the charged particle beam device operates in an imaging mode or a manipulation mode. For example, as part of the imaging mode, the control unit of the charged particle beam device can provide control signals to the beam source and beam deflection unit of the charged particle beam device to perform imaging of a sample attached to a sample stage of the charged particle beam device. As part of the manipulation mode, the control unit of the charged particle beam device provides control signals to the beam source, beam deflection unit, and precursor gas source (e.g., including a gas reservoir or tank and respective nozzles positioned near the sample stage; details are described in connection with FIG. 11A) to perform electron-beam-induced manipulation of a sample attached to the sample stage. Here, the precursor gas supplied by the precursor gas source interacts with the electrons of the electron beam. Material can be deposited or locally etched.

[0086] In the operational phase, compensation for multiple disturbances of multiple physical quantities is employed, each of the multiple physical quantities affecting a beam offset of the beam of the charged particle beam device relative to the sample stage. For example, the control unit employs the transfer function obtained from box 6005 to determine one or more compensation signals for translating the beam offset based on sensor outputs of the multiple sensors, and thereafter to provide the one or more compensation signals to one or more components of the charged particle beam device.

[0087] 7 also illustrates an optional post-processing phase associated with box 6015, in which metadata derived from the sensor outputs of the multiple sensors is used to apply one or more compensation operations to suppress beam offset by post-processing the respective image data. In some embodiments, such compensation operations include applying an imaging shift, e.g., shifting image pixels in the image data by a certain image offset. In further embodiments, rotation or skew operations are used. In some embodiments, composite image artifacts are compensated for. Examples of image artifacts include artificially recurring contrasts. To compensate for this, the compensation operations can be implemented using, for example, a neural network that determines configuration information in the form of metadata.

[0088] As indicated by the dashed line in Figure 7, the calibration mode of box 6005 can be re-run from time to time to capture certain disturbance events that are site-specific, i.e., dependent on the particular deployment site of the charged particle beam device, as will be described in more detail below.

[0089] Details regarding the calibration phase of box 6005 are now disclosed in relation to FIG.

[0090] Figure 8 is a flowchart of a method according to various embodiments. Figure 8 shows details regarding the calibration phase of box 6005.

[0091] First, in box 6105, one or more disturbances are applied. This is done by changing one or more physical quantities. Some examples are applying a particular disturbing electric or magnetic field (e.g., using a Helmholtz coil arrangement around the charged particle beam device), changing the ambient temperature (e.g., in a temperature-stabilized environment), changing the ambient pressure, etc., where the one or more disturbances are actively applied and the magnitude of each of the disturbances is known.

[0092] As can be seen above, a "tuned" disturbance event is triggered in this way for calibration purposes.

[0093] In principle, such active application of a particular disturbance is optional. In other scenarios, naturally occurring disturbances, e.g., site-specific disturbances, are measured in box 6110. In other words, in some scenarios, disturbance events are actively triggered in box 6105, while in other scenarios, environmental disturbance events are monitored and characterized in box 6110.

[0094] The beam offset can then be measured in box 6115.

[0095] This beam offset may occur as a result of a respective adjusted disturbance actively applied in box 6105, or the beam offset may occur as a result of a naturally occurring disturbance, e.g., an environmental disturbance event. For example, a beam positioning offset and / or focus offset is measured. This can be done, for example, using a test pattern sample and using a respective inspection operation. For example, in the presence of the disturbance, an image of the test pattern acquired by a charged particle device operating in imaging mode is compared with ground truth knowledge about the test pattern. A conclusion about the beam offset is drawn from the deviation between the appearance of the image of the test pattern and the ground truth about the test pattern. For example, an image shift between the true positions of certain features of the test pattern and the positions where those features are shown in the image can be determined. For example, image blur can be quantified to determine the focus offset.

[0096] Next, a transfer function between the disturbance and the beam offset is determined in box 6120. This transfer function is then stored for later use during compensation mode (see box 6010 in FIG. 7).

[0097] Next, various embodiments for determining the transfer function in box 6120 will be described.

[0098] In one embodiment, the one or more compensation signals are determined using a lookup table that links the sensor output with the one or more compensation signals. In other words, multiple disturbance intensities, e.g., multiple values ​​of each physical quantity, associated beam offsets, and the compensation signals required to compensate for them are determined. Each value pair is then stored in the lookup table. Linear interpolation is optionally used during the operating phase to improve accuracy.

[0099] The lookup tables can be device-specific, i.e., different charged particle beam devices can have different lookup tables. Site-specific disturbances can be used to populate such device-specific lookup tables. The lookup tables can also be stored in the cloud and thus can be retrieved via the Internet. This allows for centralized maintenance and management of disturbance compensation for multiple charged particle beam devices.

[0100] An example lookup table is shown in Table 1 below. [Table 1]

[0101] Such a lookup table has the advantage that it is not necessary to model the dependency between the sensor output and the compensation signal using a predetermined function. Nonlinear dependencies are captured directly. On the other hand, such a lookup table can have a considerable size. This can introduce latency in the search for an appropriate compensation signal, which can be problematic, especially in the case of rapidly changing disturbances.

[0102] In another embodiment, the compensation signal or signals are determined using a (pre-parameterized) functional dependency, which is shown for the linear case.

[0103] For example, for a scalar physical quantity, say temperature, such a linear functional dependency can be defined as follows:

number

[0104]

number

[0105] For example, for a vector physical quantity, such as an electric field, such a linear functional dependency is defined as follows:

number

[0106] In some scenarios, cross-dependencies between multiple disturbances associated with different physical quantities are considered.

[0107] For example, one example would be the cross-dependence between temperature and pressure as explained below.

number

[0108] Although linear functional dependencies are disclosed above, it is equally possible to include non-linear terms, eg, quadratic, cubic, etc.

[0109] In addition to the functional dependencies exemplified above, in another embodiment, one or more compensation signals are determined using a model. For example, compensation for positioning offset and focus offset is determined using a neural network or other machine learning algorithm, or generally a pre-trained algorithm. A trained neural network receives as input a vector including sensor outputs from multiple sensors, e.g., temperature, pressure, multiple components of an electric field, multiple components of a magnetic field, etc. The neural network then outputs one or more compensation signals, or beam offsets from which one or more compensation signals are determined. Such a neural network is trained using ground truth labels obtained during calibration mode, i.e., the measured beam offsets in box 6115, in combination with the input vectors determined in box 6105 or box 6110.

[0110] This is an example of a data-driven model. In other embodiments, analytical models may be employed. For example, it has been shown that pressure changes cause twisting of the beam optics column. This results in a circular focus deviation that is tilted relative to the plane of the sample stage, i.e., the deviation has x, y, and z components. A focus offset in the +z or −z direction may occur. In one embodiment, an analytical model is determined, which determines the torque applied to the optical column based on the pressure gradient. Such analytical models have the advantage of reduced lead time for parameterization, for example, compared to time-consuming calibration of a transfer function. In some embodiments, such models can be extended to account for positional offsets due to other disturbances, such as magnetic fields.

[0111] Above, we have disclosed a scenario for immediate compensation of disturbances. Such techniques are generally effective for slowly varying disturbances, e.g., disturbances in the kHz range or below. For fast varying disturbances, even greater accuracy can be achieved by taking into account the time-resolved characteristics of the disturbance, as will be discussed in more detail below.

[0112] According to various embodiments, a predicted component of the beam offset is determined based on the sensor outputs of the plurality of sensors, and one or more compensation signals are determined based on the predicted component of the beam offset, in other words, the disturbance is predicted some time into the future.

[0113] Such techniques are based on the observation that certain disturbance events are repetitive. Specifically, site-specific disturbance events may occur repeatedly over time. For example, stray magnetic fields may be generated by the movement of an office chair between two desks in a test lab or a charged particle beam device deployment site. For example, vibrations may be generated by trains arriving and departing at a nearby train station or delivery trucks arriving and departing at a loading dock. In another example, stray magnetic fields may be generated by the operation of equipment in a wafer fabrication plant, such as the opening and closing of load locks, the depressurization of a vacuum chamber, or temperature changes as a function of daytime / sun height. These are just a few examples of typical site-specific repetitive disturbance events.

[0114] To make such predictions, in some embodiments, the sensor output of at least one of the plurality of sensors includes respective time series data. In other words, the sensor readings (along with their respective timestamps) over a particular observation period are considered. A predictive component is then determined based on an analysis of this time series data.

[0115] There are various options for performing such an analysis of time series data. In one option, fingerprints of one or more predetermined disturbance events are detected in the time series data. These fingerprints include characteristic time dependencies of the sensor output of each of the at least one sensor. The fingerprints relate to characteristic time domain patterns. This is illustrated in relation to FIG. 9.

[0116] 9 shows, as an example, a disturbance in the x-component of the electric field affecting the beam offset of a charged particle beam over time. Time series data 310 of the x-component of the electric field is acquired from each electric field sensor.

[0117] As an example, the arrival of a bus at a bus stop near the deployment site of the charged particle beam device is shown to cause a disturbance event 311. Also shown is the respective disturbance period 313. For example, the disturbance period 313 may be in the range of a few seconds or minutes.

[0118] A disturbance event 311 has a characteristic fingerprint 312 (here, a large rise followed by a small fall) that is detected in the electric field sensor time series data. Once this fingerprint 312 is detected, a prediction can be made regarding the future behavior of the disturbance, i.e., a predicted component of the beam offset can be determined (given the repetitive nature of each disturbance). The behavior of the disturbance during the remaining disturbance period 313 can be predicted.

[0119] During operation in the calibration phase of box 6005 (see FIG. 7 ), some embodiments populate the repository with fingerprints of multiple disturbance events. Various options are possible for finding such fingerprints. In one option, fingerprint repetitions are identified. For example, during calibration mode, the sensor output of each of at least one sensor is monitored over an extended period of time, e.g., hours, days, or even weeks, and then fingerprint repetitions are found. In a further option, user-input data indicating each one of the one or more disturbance events is obtained. For example, with reference to FIG. 9 , a user labels / annotates the time series data to identify the disturbance period 313. The user may do this through domain knowledge; for example, in the described embodiment, the user may be aware of the arrival of a bus at a bus stop. Another option includes training a predictive model based on the time series data measured during calibration mode to find the fingerprints. In that case, a predictive model, e.g., a recurrent neural network such as a long short-term memory (LSTM) neural network, is enabled to determine the predicted component of the beam offset. This makes it possible to react to disturbance events with high bandwidth signal content, i.e., to compensate for disturbance events with fast time dynamics, for example in the sub-millisecond or even microsecond range, since a compensation signal can be proactively deployed once the fingerprint has been detected.

[0120] 10 is a flow chart of an example method, which illustrates generally the operations in the operational phase of box 6010 of FIG.

[0121] In box 6205, a plurality of sensors of the charged particle beam device measure a plurality of disturbances of a plurality of physical quantities, each of which affects a beam offset, e.g., a position offset and / or a focus offset, of the charged particle beam on the sample stage. Respective sensor outputs are provided, which include a plurality of sensor signals provided by the plurality of sensors. The sensor outputs indicate values ​​of the physical quantities. That is, the sensor outputs are associated with the disturbances. The disturbances may overlap with each other or may be correlated with each other.

[0122] In principle, different arrangements of sensors are possible, and example arrangements are described below in connection with Figures 12 and 13.

[0123] Next, in box 6210, one or more compensation signals for suppressing such beam offset are determined based on the sensor outputs of the multiple sensors. More specifically, disturbances are estimated from the sensor outputs and converted into one or more compensation signals.

[0124] Thus, embodiments have been disclosed that facilitate the determination of such compensation signals using, for example, transfer functions that may be implemented by lookup tables, models, data-driven models using, for example, machine learning or analytical models, functional dependencies, machine learning algorithms, etc.

[0125] It is also possible to determine a predicted component of the beam offset to reduce latency, apply a compensation signal, and provide more accurate compensation.

[0126] In some scenarios, instead of or in addition to determining a compensation signal for actively compensating for beam offset during operation of the charged particle beam device, e.g., in an imaging mode or a manipulation mode, metadata is determined that indicates one or more compensation operations for suppressing beam offset in the imaging data. This enables post-processing of the imaging data (see box 6015 in FIG. 7 ). Here, compensation for beam offset occurs when digitally post-processing imaging data acquired using the charged particle beam device, instead of or in addition to compensating for at least a portion of the beam offset during operation.

[0127] The reliability of each image data can be determined. A log file can be generated to store the disturbances or specifically the compensation signal or signals.

[0128] In box 6211, optionally, the accuracy of operation of the charged particle beam device during a prediction period can be predicted based on the sensor outputs and / or the one or more compensation signals determined in box 6210. This can be the same as predicting the level of disturbance. For example, a recurrent neural network or an LSTM is used to make such a prediction. Again, such a prediction can be based on characteristic fingerprints of recurring disturbance events, as described in connection with FIG. 9. Unlike what was described in connection with FIG. 9, such a prediction of the level of accuracy may not directly affect the compensation signals. In some cases, the prediction may not be accurate enough to determine the predictive components of one or more compensation signals. Even in such a scenario, it is possible to predict the accuracy. In some embodiments, such accuracy is output to a user via an HMI. The user can then decide whether or not to abort the operation. In other embodiments, the prediction of the accuracy is used in the context of box 6215.

[0129] In some cases, scenarios arise where a disturbance exceeds or is predicted to exceed a certain predetermined threshold (see box 6211). If the disturbance exceeds the predetermined threshold, such disturbance is deemed unable to be compensated for.

[0130] Thus, in box 6215, it is determined whether one or more predetermined events are detected in the sensor outputs of the plurality of sensors. In some embodiments, such one or more predetermined events are associated with at least one of the plurality of disturbances exceeding a certain predetermined threshold, which corresponds to the sensor output exceeding the respective threshold. In further embodiments, it is determined whether one or more compensation signals exceed a certain threshold. Another example of such one or more predetermined events is the detection of an anomaly in the sensor output. In some embodiments, an anomaly detection algorithm is used. Examples include cluster-based anomaly detection or an autoencoder neural network. Such an anomaly detection algorithm can be trained in an unsupervised manner.

[0131] If one or more predetermined events are not detected in box 6215, box 6205 is re-executed, i.e., the disturbance is measured again and a compensation signal is further applied. On the other hand, if an excessive disturbance is detected in box 6215, the beam is blanked in box 6220. For example, the inspection mode or manipulation mode is aborted. Alternatively or additionally, a warning message is output via the HMI. In some embodiments, each sensor output leading to execution of box 6220 is logged. According to some embodiments, a safe mode is entered that can be manually exited by the user.

[0132] Beam blanking is performed with a relatively low latency to avoid damage. For example, determining one or more compensation signals typically requires a significant amount of time, e.g., to perform a search operation or to calculate a compensation signal. Thus, in some embodiments, beam blanking is performed with a lower latency than such determining one or more compensation signals.

[0133] In principle, the decision in box 6215 may, according to some embodiments, be based on sensor signals other than those considered by the logic in box 6210. For example, the following physical quantities have been found to be particularly suitable for detecting excessive disturbances in box 6215: acoustic vibration, vibration, environmental pressure, and environmental pressure changes. On the other hand, the following physical quantities have been found to be particularly suitable for determining one or more compensation signals to suppress beam offset: magnetic field, environmental temperature, environmental pressure, and environmental pressure changes.

[0134] FIG. 11 illustrates a schematic diagram of an exemplary embodiment of a charged particle beam device, such as the charged particle beam device 100 described above. The scenario in FIG. 11 pertains to a charged particle beam repair device (or simply, repair device). FIG. 11 illustrates a schematic cross-sectional view of some key components of an example repair device 11120 that can be used to identify and repair defects 11160 in a photolithography mask. For example, a sample 11405 in the form of a photolithography mask 11110 can be placed on a sample stage 11402 (corresponding to sample stage 113). The photomask may have one or more defects 11160 in the form of excess material ("dark defects") and / or missing material ("bright defects"). The defects in the photolithography mask are not reproduced in FIG. 11. The defects, or generally defects of excess or missing material, can be scanned using a charged particle beam and thus analyzed. Additionally, particle-beam-induced machining processes can be used to correct the defects. To this end, the repair device 11120 includes a scanning electron microscope (SEM) 11410. Additionally, defects in the excess material can be repaired using the measuring tip of a scanning probe microscope 11480. Accordingly, the repair device 11120 includes one or more scanning probe microscopes 11480, typically in the form of an atomic force microscope (AFM) 11480.

[0135] In the SEM 11410 of FIG. 11 , an electron gun embodying a beam source 11412 generates an electron beam 11415, which an imaging element (embodying a beam deflection unit) not shown in FIG. 11 , located in an electron column 11417, directs / deflects as a focused electron beam 11415 onto a sample 11405 at location 11422, which may include a photolithography mask as previously described. The sample 11405 is located on a sample stage 11402, which is also referred to in the art as a "stage." As represented by the arrows in FIG. 11 , a positioning unit 11407 can move the sample stage 11402 about six axes relative to the column 11417 of the SEM 11410. Movement of the sample stage 11402 by the positioning unit 11407 can be achieved, for example, using a micromanipulator not shown in FIG. 11 .

[0136] At the processing location 11422, the particle beam 11415 is incident on the sample 11405. Thus, the positioning unit 11407 allows for analyzing defects in the photomask (inspection operation) by first generating an image of the defect through displacement of the sample stage 11402 perpendicular to the beam axis of the electron beam 11415. For this purpose, an imaging element of the column 11417 of the SEM 11410 can scan the electron beam 11415 over the sample 11405. Using tilting and / or rotation of the six-axis sample stage 11402, the sample stage 11402 allows for the inspection of one or more defects from different angles or perspectives. The respective positions of the various axes of the sample stage 11402 can be measured by interferometry (not reproduced in FIG. 11 ). The positioning unit 11407 is controlled by signals from the control unit 11425. The control unit 11425 may be part of the computer system 11430 of the repair device 11120. The control unit 11425, in some embodiments, implements the control unit 119 or the control unit 130 (see FIG. 6).

[0137] The repair device 11120 further includes one or more sensors that allow characterization of both the current state of the SEM 410 and the process environment (e.g., vacuum environment) in which the SEM 11410 is being used. For example, vibration, temperature, pressure, and their respective differentials or rates of change (over time) can be measured.

[0138] The electron beam 11415 can further be used to induce particle beam induced machining processes that repair the identified defects, for example, in the context of an electron beam induced etching process (EBIE) to remove dark defects and / or an electron beam induced deposition process (EBID) to repair bright defects. Additionally, in the repair device 11120 of FIG. 11, the electron beam 11415 can be used to analyze the repair locations on the photomask.

[0139] Electrons backscattered from the electron beam 11415 by the sample 11405 and secondary electrons generated by the electron beam 11415 at the sample 11405 are recorded by the detector 11420. If the sample 11405 includes a photomask, the detector 11420 identifies secondary electrons emitted during the scanning of an absorbing strip disposed on the photomask for lithography. The detector 11420 disposed within the electron column 11417 is referred to as an "in-lens detector." In various embodiments, the detector 11420 can be disposed within the column 11417. The detector 11420 can also be used to detect electrons backscattered from one or more defects 11160 in the mask 11110. The detector 11420 is controlled by a control unit 11425 of a computer system 11430 of the device 120. For example, the computer system 11430 can implement the control unit 130. The control unit 11425 could also implement the built-in control unit 119.

[0140] The repair device 11120 can include a second detector 11445. The second detector 11445 is designed to detect electromagnetic radiation, particularly in the x-ray range. As a result, the second detector 11445 allows for analyzing the material composition of a sample, for example a photolithography mask, i.e., its substrate, absorber strips, and / or one or more defects. The detector 11445 is likewise controlled by the control unit 11425.

[0141] A control unit 11425 of the computer system 430 (which may be separate from the computer system 430) can set parameters of the electron beam 11415 to induce a deposition process to remove bright defects and / or an EBIE process to etch dark defects.

[0142] The computer system 11430 also has an evaluation unit 11435. The evaluation unit 11435 receives measurement data from the detectors 11420, 11445. The evaluation unit 11435 can generate from the measurement data, for example from secondary electron contrast data, an image with a grayscale representation or grayscale value representation that is displayed on the monitor 11432. Furthermore, the computer system 11430 includes an interface 11437 via which the computer system 11430 can transmit to further processing devices. The computer system 11430 of the repair device 11120 can also receive one or more processed or evaluated images and / or one or more overlaid images from the evaluation device.

[0143] As already explained above, the electron beam 11415 of the modified SEM 11410 can be used to induce electron beam induced machining processes / manipulation. Also as already explained above, electron beam induced manipulation can be used to repair defects in the sample 11405. To perform these processes, the example scanning electron microscope 11410 of the repair device 11120 of FIG. 11 has three different supply containers 11450, 11460, and 11470.

[0144] The first supply container 11450 stores a first precursor gas in the form of a deposition gas, such as a metal carbonyl, e.g., chromium hexacarbonyl (Cr(CO)6), or a carbon-containing precursor gas, e.g., pyrene. The precursor gas stored in the first supply container 11450 can be used to deposit material on the sample 11405 or mask by local chemical reaction with the electron beam 11415 of the SEM 11410, which acts as an energy source, to split the precursor gas stored in the first supply container 11450 into preferably chromium atoms and carbon monoxide molecules at the intended location of material deposition, i.e., at the location of bright defects. This means that the EBID process for repairing defects in a photomask is carried out by the combined supply of the electron beam 11415 and the precursor gas. The modified SEM 11410, combined with the first supply container 11450 or the volumetric gas stored therein, forms the repair device 11120.

[0145] In the repair device 11120 shown in FIG. 11, the second supply container 11460 stores a precursor gas in the form of an etching gas that enables a localized electron beam induced etching (EBIE) process to be performed. The electron beam induced etching process can be used to remove excess material or dark defects from a photolithography mask 11110 (or other sample, such as a semiconductor wafer). The precursor gas in the form of an etching gas can include, for example, xenon fluoride (XeF), chlorine (Cl), oxygen (O), ozone (O), water vapor (H), hydrogen peroxide (H), nitrous oxide (N), nitric oxide (NO), nitrogen dioxide (N), nitric acid (HNO), ammonia (NH), or sulfur hexafluoride (SF), or a combination thereof. Thus, the improved SEM 11410 combines with the second supply container 11460 or the precursor gas stored therein to form the repair device 11120.

[0146] Third supply container 11470 can store an additive gas that can be added, when needed, to the etching gas maintained as available in second supply container 11460 or to the deposition gas stored in first supply container 11450. Alternatively, third supply container 11470 can store a precursor gas in the form of a second deposition gas or a second etching gas.

[0147] In the scanning electron microscope 11410 shown in Figure 11, each of the supply vessels 11450, 11460 and 11470 has its own control valve 11452, 11462 and 11472 to monitor or control the amount of corresponding gas supplied per unit time, i.e., the gas volumetric flow rate at the location 11422 of incidence of the electron beam 11415 on the sample 11405. The control valves 11452, 11462 and 11472 are controlled and monitored by a control unit 11425. By this means, partial pressure conditions of one or more gases supplied to the processing location 11422 for performing the EBID and / or EBIE processes (see box 6010 in Figure 7) can be set over a wide range during operation.

[0148] Also, in the example SEM 11410 of FIG. 11, each supply vessel 11450, 11460, and 11470 has its own gas supply piping 11454, 11464, and 11474 that terminates in a nozzle 11456, 11466, and 11476 near the point of incidence, i.e., the processing location 11422, of the electron beam 11415 on the sample 11405.

[0149] The supply vessels 11450, 11460, and 11470 can have their own temperature setting and / or control elements that allow both cooling and heating of the corresponding supply vessels 11450, 11460, and 11470. This allows for storing and specifically supplying deposition and / or etching gas precursor gases, respectively, at optimal temperatures (not shown in FIG. 11). The control unit 11425 can control the temperature setting and temperature control elements of the supply vessels 11450, 11460, and 11470. During the EBID and EBIE fabrication processes, the temperature setting elements of the supply vessels 11450, 11460, and 11470 can further be used to set the vapor pressure of the process gases stored therein by selecting the appropriate temperature.

[0150] The device 11400 can include multiple supply vessels 11450 for storing precursor gases for two or more deposition gases, and the device 400 can include multiple supply vessels 11460 for storing precursor gases for two or more etching gases.

[0151] The scanning electron microscope 11410 shown in FIG. 11 can be operated under ambient conditions or within a vacuum chamber 11442. The implementation of the EBID and EBIE processes requires a negative pressure within the vacuum chamber 11442 relative to ambient pressure. To this end, the SEM 11410 of FIG. 11 includes a pumping system 11444 for creating and maintaining the necessary negative pressure within the vacuum chamber 11442. With the control valves 11452, 11462, and 11472 closed, a pressure of <10 s is achieved within the vacuum chamber 11442. -4A residual gas pressure of 100 Pa is obtained. The pumping system 11444 may include separate pumping systems (not shown in FIG. 11 ) for the upper part of the vacuum chamber 11442 to supply the electron beam 11415 of the SEM 11410 and for the lower part of the reaction chamber 11448. Pressure sensors may be provided to monitor the pressure inside and outside the vacuum chamber 11442. The pressure difference may be monitored.

[0152] The SEM 11410 shown in the repair device 11120 of FIG. 11 has a single electron beam 11415. However, it is also possible for the SEM 11410 to have a source of a second particle beam. The second particle beam may include a photon beam and / or an ion beam (not shown in FIG. 11). The SEM 11410 may also have two or more electron beams 11415 so that two or more particle-beam-induced machining processes or two or more analysis processes for two or more defects can be performed in parallel.

[0153] 11 includes a scanning probe microscope 11480, which may be realized in the form of a scanning force microscope (SFM) 11480 or an atomic force microscope (AFM) 11480. The scanning probe microscope 11480 may be used to scan one or more defects 11160 in the sample 11405 or in the photomask 11110. The scanning probe microscope 11480 may also be used to repair defects in excess material. To this end, the scanning probe microscope 11480 may include a first measurement tip for analyzing the sample 11405 and a second measurement tip for machining the one or more defects.

[0154] Only the measurement head 11485 of the scanning probe microscope 11480 is shown in the repair device 11120 of Figure 11. In the embodiment of Figure 11, the measurement head 11485 includes a holding device 11487. The measurement head 11485 is fixed to the frame of the repair device 11120 using the holding device 11487 (not shown in Figure 11). A piezoelectric actuator is attached to the holding device 11487 of the measurement head 11485, which allows the free end of the piezoelectric actuator 11490 to move in three spatial directions (not shown in Figure 11). A probe 11492, which includes a cantilever 11494 or lever arm 11494 and a measuring tip 11495, is fixed to the free end of the piezoelectric actuator 11490. The free end of the cantilever 11494 of the probe 1192 has a measuring tip 11495.

[0155] 12 and 13, options for positioning sensors 800 are disclosed that can be used to measure disturbances in physical quantities, each of which affects the beam offset of the beam 11415 of the repair device 11120. The repair device 11120 is shown only schematically in FIGS. 12 and 13 at a higher level of abstraction compared to FIG. 11. In addition to what is disclosed in FIG. 11, FIGS. 12 and 13 also disclose a beam blanker 11801 that can be used to blank the beam 11415, an aperture 11802 for deflecting the beam (i.e., forming the optics of the beam deflection unit 112), and electrical coils 11803 and 11804.

[0156] In the scenario of Figure 12, the sensor 800 is located outside the vacuum chamber 11442 of the repair device 11120. In the scenario of Figure 13, the sensor 800 is located inside the vacuum chamber 11442 of the repair device 11120. Combinations are also possible, i.e. some sensors may be located inside the vacuum chamber while other sensors may be located outside the vacuum chamber.

[0157] 14 and 15 illustrate a highly accurate mask repair operation achievable by the repair device 11120 of the preceding figures. In the first step shown in FIG. 14, a mask defect 1471.1 at an absorption line 1453 on the substrate layer 1451 of the mask is determined with high accuracy. Using the inspection mode, a precise determination of the extent of the defect 1471.1, including at least the tilt angle 1473.1 of the defect 1471.1, is determined. The defect edge position, the deviation of the edge position from the target range, and the extent of the defect can be determined with an accuracy of less than 1 nm, preferably even 0.5 nm. The missing volume of material to be deposited in the repair operation can be determined with high accuracy. In the repair step (manipulation mode), the defect 1471.1 is filled, for example, with chromium, using, for example, low-energy electron-beam-assisted deposition of material from a precursor gas supplied by a gas supply system, thereby forming a repaired defect 1477. This is shown in FIG. 15. The accuracy of the repair operation is then verified by the device in inspection mode. The resulting edge position of line 1453 and the slope angle 1473.2 of the line edge are obtained with high precision. This keeps the repair operation very well within the mask specification requirements, including the stringent requirements of EUV masks with edge positions of less than 0.5 nm or even smaller. The repair and verification steps can also be performed iteratively. Such manipulation is not limited to missing material in a mask layer, but is equally applicable to removing excess material in a mask layer. Furthermore, manipulation is not limited to mask repair, but also applies to circuit repair operations on processed wafers. In both embodiments, layer material is removed by electron-beam-induced etching or deposited by electron-beam-induced deposition, and high-precision processing endpoint detection is required.

[0158] FIG. 16 illustrates a schematic diagram of an exemplary embodiment of a charged particle beam device, such as the charged particle beam device 100 described above.

[0159] The charged particle beam device 161001 of Figure 16 is an aberration-reduced low-energy corrected electron microscope, as described in German Patent Application No. 102019214936, filed September 27, 2019, which is incorporated herein by reference. Generally, low-energy corrected electron microscopes include means for correcting chromatic aberration (CC), spherical aberration (CS), and optionally also field curvature (FC). The low-energy corrected single-beam charged particle microscope 161001 includes a beamlet generator 161301 for generating a single primary charged particle beamlet 161003 and an object illumination unit 161100 for illuminating an image subfield on the surface of a sample 11110 (e.g., a lithography mask or a semiconductor wafer containing semiconductor structures) arranged in the object plane 16101, thereby generating a secondary electron beamlet 161009 that, in use, emanates from a focal point 161605 of the primary beamlet 161003 within the image subfield. The subfields typically have a lateral extent of at least 5 μm, preferably 8 μm, 12 μm or more. The object illumination unit 161100 further includes first to third electrostatic or magnetic lenses 161403, 161405, and 161407, and an objective lens 161102. The charged particle microscope 16100 further includes a detection unit 161200 for acquiring a digital image of the image subfields on the surface of the sample during use. The detection unit 161200 includes an electronic sensor 161207 and optional electrostatic or electromagnetic deflection elements 161205. The charged particle microscope 161001 further includes an electromagnetic beam splitting system 161400 for directing the primary beamlet 161003 along a primary beam path (solid line 161013) and the secondary beamlet 161009 along a secondary beam path (dashed line 161011). The secondary beamlets 161009 collected by the objective lens 161102 propagate counter to the primary beamlets 161003 and are therefore separated from the primary beamlets 161003 by the magnetic beam splitting system 161400. The charged particle microscope 161001 further comprises a long straw cluster scanner 161110. The raster scanner 16110 (forming a beam deflection unit) comprises at least a first set of deflection electrodes 161111.The charged particle microscope 161001 further includes a control unit 16800 (implementing the control unit 119 or the control unit 130). The charged particle microscope 161001 further includes at least a first corrector 161601 for correcting the primary charged particle beamlet 161003. The charged particle system 161001 further includes a correction system 161052 having a second optical axis 161050 angled with respect to the optical axis 16105. A beam splitter system 161400 directs the primary beamlet in the direction of the second optical axis 161050 into the correction system 161052. The correction system includes an electrostatic mirror 161414 that reflects the primary beamlet to the beam splitter system 161400. In one embodiment, the second corrector 161602 is disposed in the correction system 161052 together with the correction electrode 161612. The low energy corrected single beam charged particle microscope 161001 allows electron imaging with kinetic energies of less than 400 eV, preferably less than 300 eV, even more preferably less than 200 eV, or even more preferably less than 150 eV, achieving high resolution of less than 2 nm, preferably less than 1.5 nm, and even more preferably 1 nm using low incident energy primary electrons and the correction means of the low energy electron microscope.

[0160] The charged particle beam is again located within a vacuum chamber (not shown in FIG. 16). The sensor can be located inside and / or outside the vacuum chamber, as described above in connection with FIGS. 14 and 15.

[0161] In summary, techniques have been disclosed that facilitate compensation for multiple disturbances caused by multiple physical quantities that affect the beam offset of a beam in a charged particle beam device. Such compensation is performed during imaging or manipulation mode, for example, for mask repair or circuit addition. Such compensation is possible, particularly if the disturbance / beam offset is within a predetermined range. Otherwise, if the disturbance cannot be compensated, the imaging or manipulation mode is stopped, for example, by blanking the beam and / or closing a precursor gas supply valve, according to an embodiment. According to an embodiment, a warning is output. After the disturbance is resolved, operation is resumed from the point where the process was stopped. Using the techniques disclosed herein, improved quality of imaging or manipulation operations can be achieved. The risk of damaging expensive lithography masks or semiconductor devices being manipulated can be reduced.

[0162] Also disclosed is a technique that facilitates using sensor outputs from multiple sensors to predict future behavior of a charged particle beam device. For example, sensor outputs can be stored in a data repository, and multiple time series can be correlated with each other. Correlations can be found, and repeating fingerprints can be identified, which can be used to make predictions about future behavior of the charged particle beam device. For example, predictive maintenance information can be obtained by using a microphone to acquire an acoustic frequency spectrum and / or acoustic noise pressure, for example, to detect continuously increasing noise levels at certain frequencies in the acoustic spectrum that may indicate a failure of one or more components, such as a pump, of the charged particle beam device.

[0163] In various embodiments, machine learning algorithms, such as deep neural networks, are used to analyze sensor output. Training can be repeated from time to time based on training data acquired during calibration mode, thus continually improving accuracy. Additionally, site-specific training based on site-specific calibration is possible.

[0164] In summary, at least the following embodiments have been disclosed as defined by the following items:

[0165] Item 1. A charged particle beam device including a beam source, a beam deflection unit, and a sample stage, wherein the beam deflection unit is configured to deflect a beam of charged particles emanating from the beam source to position the beam on the sample stage, and the charged particle beam device is configured to: - one or more sensors configured to measure one or more disturbances of one or more physical quantities, each of which affects a beam offset of a beam on the sample stage; - at least one control unit configured to determine one or more compensation signals for suppressing beam offset based on sensor outputs of the one or more sensors; wherein at least one control unit is configured to provide one or more compensation signals to at least one of the beam source, the beam deflection unit, the sample stage, or the one or more compensation modules.

[0166] Item 2. The charged particle beam device of item 1, A charged particle beam device, wherein at least one control unit is configured to determine a predicted component of the beam offset based on sensor outputs of the one or more sensors, and to determine one or more compensation signals based on the predicted component of the beam offset.

[0167] Item 3. The charged particle beam device of Item 2, a sensor output of at least one sensor of the one or more sensors including respective time series data; A charged particle beam device, wherein the at least one control unit is configured to determine a predictive component based on an analysis of time series data of sensor output of at least one sensor of the one or more sensors.

[0168] Item 4. The charged particle beam device according to Item 3, A charged particle beam device, wherein analyzing the time series data includes finding fingerprints of one or more predetermined disturbance events in the time series data and / or applying a recurrent neural network, such as a long short-term memory network.

[0169] Item 5. The charged particle beam device according to Item 4, at least one control unit configured to selectively activate the calibration phase; A charged particle beam device, wherein when operating in a calibration phase, at least one control unit is configured to enter fingerprints of one or more disturbance events into a repository, for example, based on at least one of identifying respective repetitions of the fingerprints in the time series data or obtaining user input data indicative of a respective one of the one or more disturbance events.

[0170] Item 6. The charged particle beam device according to Item 4 or 5, at least one control unit configured to selectively activate the calibration phase; A charged particle beam device, wherein when operating in a calibration phase, the at least one control unit is configured to train a predictive model based on the time series data measured during the calibration phase to find the fingerprint and thereby enable the predictive model to determine a predictive component.

[0171] Item 7. A charged particle beam device according to any one of the preceding items, The charged particle beam device, wherein the at least one control unit is further configured to predict accuracy of operation of the charged particle beam device during a prediction period based on at least one of the sensor output or the one or more compensation signals.

[0172] Item 8. The charged particle beam device according to Item 7, A charged particle beam device, wherein the at least one control unit is further configured to selectively discontinue operation of the charged particle beam device depending on the accuracy of the operation, for example by blanking the beam.

[0173] Item 9. A charged particle beam device according to any one of the preceding items, The charged particle beam device, wherein the one or more disturbances include a plurality of disturbances, and the at least one control unit is configured to determine one or more compensation signals based on cross-dependencies between the plurality of disturbances.

[0174] Item 10. The charged particle beam device according to Item 9, A charged particle beam device, wherein the at least one control unit is configured to determine one or more compensation signals based on a cross-dependence relationship between a temperature-induced disturbance and a pressure-induced disturbance.

[0175] Item 11. A charged particle beam device according to any one of the preceding items, A charged particle beam device, wherein at least one control unit is configured to determine one or more compensation signals based on a pre-trained algorithm.

[0176] Item 12. The charged particle beam device according to item 11, A charged particle beam device in which the pre-trained algorithm includes a deep neural network, such as a convolutional neural network.

[0177] Item 13. The charged particle beam device according to item 11, A charged particle beam device, wherein the pre-trained algorithm comprises a machine learning algorithm.

[0178] Item 14. The charged particle beam device according to any one of the preceding items, wherein at least one control unit is configured to determine one or more compensation signals based on a pre-parameterized functional dependency.

[0179] Item 15. A charged particle beam device according to any one of the preceding items, A charged particle beam device, wherein the at least one control unit is configured to determine the one or more compensation signals using a look-up table linking sensor outputs to the one or more compensation signals.

[0180] Item 16. The charged particle beam device according to Item 15, A charged particle beam device, wherein the lookup table is retrieved from a device-specific repository associated with the charged particle beam device.

[0181] Item 17. The charged particle beam device according to Item 15, A charged particle beam device, wherein the lookup table is retrieved from a cloud storage repository associated with a plurality of charged particle beam devices.

[0182] Item 18. A charged particle beam device according to any one of the preceding items, 1. A charged particle beam device, wherein the plurality of physical quantities are selected from the group including acoustic vibration, vibration, pressure, humidity, temperature, laminar flow, turbulent flow, differential quantity, rate of change of physical quantity, vector quantity, and scalar quantity.

[0183] Item 19. A charged particle beam device according to any one of the preceding items, A charged particle beam device, wherein the one or more sensors include at least one sensor for measuring a temperature or a pressure of a cooling fluid.

[0184] Item 20. A charged particle beam device according to any one of the preceding items, A charged particle beam device, wherein at least one of the one or more sensors is disposed inside a vacuum chamber of the charged particle beam repair device.

[0185] Item 21. A charged particle beam device according to any one of the preceding items, A charged particle beam device, wherein at least one of the one or more sensors is located outside a vacuum chamber of the charged particle beam device.

[0186] Item 22. A charged particle beam device according to any one of the preceding items, A charged particle beam device, wherein the one or more sensors include at least one sensor for measuring a pressure or temperature difference between two or more components of the charged particle beam repair device.

[0187] Item 23. A charged particle beam device according to any one of the preceding items, A charged particle beam device, wherein the one or more disturbances are selected from the group consisting of: direct disturbances that affect the beam offset by deflecting the beam; and indirect disturbances that affect the beam offset by affecting one or more components of the charged particle beam device.

[0188] Item 24. A charged particle beam device according to any one of the preceding items, A charged particle beam device, wherein the beam offset includes at least one of a position offset or a focus offset.

[0189] Item 25. A charged particle beam device according to any one of the preceding items, A charged particle beam device, wherein the at least one control unit is configured to monitor a sensor output of at least one of the one or more sensors or a further sensor output of the at least one further sensor, and selectively blank the beam based on the monitoring.

[0190] Item 26. The charged particle beam device according to Item 25, A charged particle beam device, wherein at least one control unit is configured to selectively blank the beam with less latency compared to said determining one or more compensation signals.

[0191] Item 27. A charged particle beam device according to any one of the preceding items, The charged particle beam device, wherein at least one control unit is configured to provide one or more compensation signals by the charged particle beam device operating in a manipulation mode, such as an electron beam induced etching or deposition mode, the manipulation mode including repairing or modifying a semiconductor device on a wafer mounted on a sample stage.

[0192] Item 28. A charged particle beam device according to any one of the preceding items, A charged particle beam device, wherein the charged particle beam device is a charged particle beam repair device.

[0193] Item 29. A charged particle beam device according to any one of the preceding items, A charged particle beam device, wherein the charged particles are electrons or ions, such as helium ions or neon ions.

[0194] Item 30. A charged particle beam device according to any one of the preceding items, A charged particle beam device, wherein the charged particle beam device is a combined focused ion beam electron microscope cross beam device.

[0195] Item 31. The charged particle beam device of any one of the preceding items, wherein the charged particle beam device is a charged particle beam repair device, and the charged particle beam repair device further comprises a precursor gas source; A charged particle beam device, wherein at least one control unit is configured to provide control signals to a beam source, a beam deflection unit, and a precursor gas source for performing electron beam induced manipulation of a sample mounted on a sample stage, and wherein the at least one control unit is configured to provide one or more compensation signals during the electron beam induced manipulation.

[0196] Item 32. A charged particle beam device according to any one of the preceding items, wherein at least one control unit is configured to provide the one or more compensation signals while the charged particle beam device is operating in an imaging mode that includes imaging a structure of the sample mounted on a sample stage.

[0197] Item 33. A charged particle beam device according to any one of the preceding items, A charged particle beam device, wherein at least one control unit determines one or more compensation signals according to a linear or non-linear dependence of the one or more compensation signals on the sensor output.

[0198] Item 34. A charged particle beam device according to any one of the preceding items, the one or more disturbances include multiple disturbances; A charged particle beam device in which one or more physical quantities include multiple physical quantities.

[0199] Item 35. A charged particle beam device according to any one of the preceding items, A charged particle beam device, wherein the one or more compensation modules are selected from the group comprising: a coil for applying a magnetic field, an external field plate for applying an electric field, a Helmholtz coil pair, an active cooling or heating element, an active damping element, a pressure control element such as a pump, external to the vacuum chamber or housing of the charged particle beam device, i.e., external to the vacuum chamber or housing of the charged particle beam device.

[0200] Item 36. A charged particle beam device including a beam source, a beam deflection unit, and a sample stage, wherein the beam deflection unit is configured to deflect a beam emitted from the beam source to position the beam on the sample stage, and the charged particle beam device is - one or more sensors, each configured to measure one or more disturbances of one or more physical quantities that affect the beam offset of the beam on the sample stage; - at least one control unit configured to determine, based on sensor output of the one or more sensors, metadata indicative of one or more compensation actions for suppressing beam offset in image data acquired by the charged particle beam device operating in an imaging mode, and to store the metadata in association with the image data.

[0201] Item 37. The charged particle beam device according to Item 36, A charged particle beam device, wherein the one or more compensation operations are selected from the group including image shift, rotation, skew, contrast enhancement, and blur reduction.

[0202] Item 38. - monitoring physical quantities that cause disturbances to a beam of a charged particle beam device; - compensating for disturbances based on said monitoring.

[0203] Item 39. The method according to Item 38, A method wherein said compensating for the disturbance comprises applying a voltage or current to the electron optics of a beam deflection unit of the charged particle beam device to move the beam in a direction opposite to the beam offset caused by the disturbance.

[0204] Item 40. The method according to Item 38 or 39, A method wherein said compensating or reducing the disturbance comprises moving a sample stage of a charged particle beam device in the direction of the beam offset caused by the disturbance.

[0205] Item 41. The method according to any one of items 38 to 40, wherein the time latency between the monitoring and the compensation or reduction is less than 50 milliseconds, optionally less than 500 milliseconds, and optionally less than 5 seconds.

[0206] Item 42. The method according to any one of Items 38 to 41, A method wherein the compensation or reduction is performed while the charged particle beam device is operating in a manipulation mode involving electron beam induced etching of material from or deposition of material onto a wafer mask.

[0207] Item 43. The method according to any one of Items 38 to 42, - selectively ceasing operation of the charged particle beam device based on said monitoring.

[0208] Item 44. The method according to Item 43, A method wherein said selectively ceasing operation of the charged particle beam device comprises blanking the beam.

[0209] Item 45. The method according to Item 43 or 44, The method further comprising selecting between performing the compensation for the disturbance and performing the deactivation based on the monitoring.

[0210] Item 46. A method of manipulating or imaging a sample mounted on a sample stage of a charged particle beam device, the charged particle beam device including a beam source, a beam deflection unit, and a sample stage, the beam deflection unit configured to deflect a beam of charged particles emanating from the beam source to position the beam on the sample stage, the method comprising: - acquiring sensor outputs of one or more sensors of the charged particle beam device, the one or more sensors measuring one or more disturbances of one or more physical quantities each affecting a beam offset of the beam on the sample stage; - determining one or more compensation signals to suppress beam offset based on the sensor output of the one or more sensors; - providing one or more compensation signals to the beam source, the beam deflection unit, the sample stage or one or more compensation modules.

[0211] Item 47. The method according to Item 46, which is executed by a control unit of the charged particle beam device according to Item 1.

[0212] Item 48. A method for post-processing image data acquired by a charged particle beam device including a beam source, a beam deflection unit, and a sample stage, wherein the beam deflection unit is configured to deflect a beam of charged particles emanating from the beam source to position the beam on the sample stage; - acquiring sensor outputs from one or more sensors of the charged particle beam device, the one or more sensors measuring one or more disturbances of one or more physical quantities each affecting a beam offset of the beam on the sample stage; - determining metadata indicative of one or more compensation actions to suppress beam offset in image data acquired by the charged particle beam device operating in an imaging mode based on sensor outputs of the one or more sensors; - post-processing the image data according to one or more compensation operations based on the metadata.

[0213] Item 49. The method of item 48, which is at least partially performed by a control unit of the charged particle beam device of item 36.

[0214] While the present invention has been shown and described with reference to certain preferred embodiments, equivalents and modifications will occur to those skilled in the art upon reading and understanding the specification. The present invention includes all such equivalents and modifications, and is limited only by the scope of the appended claims.

[0215] For illustrative purposes, the various embodiments above have been disclosed in the context of a charged particle beam repair device that performs repair operations using electron beam induced manipulation of a sample, i.e., EBID and / or EBIE. In principle, repair operations using physical action using ions, i.e., FIB etching, can also be employed. Furthermore, the techniques disclosed herein are not limited to charged particle repair devices, but can also be used to compensate for disturbances during circuit repair operations on semiconductor wafers of the respective imaging charged particle beam device, or during inspection or measurement operations while operating in imaging mode.

[0216] For illustrative purposes, the various embodiments described above are disclosed in the context of charged particle beam devices employing charged particles, such as electrons or ions. Similarly, the techniques disclosed herein can also be applied to non-charged particle beam devices, such as photon-based microscopes. In this case, disturbances can be generated by physical quantities such as seismic vibrations, acoustics, pressure changes, wind speed changes, humidity changes, and temperature. The respective beam devices can be, for example, lasers, x-ray inspection tools, etc. Compensation can be achieved by shifting the sample stage to suppress beam offset, as described in connection with FIGS. 1-5.

[0217] Also disclosed is a technique for active compensation of beam offsets due to disturbances of physical quantities. Such techniques can be applied in conjunction with passive shielding. For example, acoustic vibrations, thermal drift, laminar or turbulent flow can be reduced by enclosing beam-related components of a charged particle beam device in a housing. Noise-absorbing materials are attached to the housing. Passive or active vibration damping systems can be used to support the housing above the floor.

Claims

1. A charged particle beam repair device (100, 11120, 11410, 161001) comprising a beam source (111, 11412), a beam deflection unit (112, 11417), a precursor gas source (11456, 11466, 11476, 11450, 11460, 11470, 11452, 11462, 11472) and a sample stage (114, 11402), wherein the beam deflection a deflection unit (112, 11417) configured to deflect a beam of charged particles (90, 91, 92, 93, 94, 95, 11415, 161003, 161009) emanating from the beam source in order to position the beam on the sample stage (113, 11402); and the charged particle beam repair device (100, 11120, 11410, 161001) a plurality of sensors (121, 122, 800) configured to measure a plurality of disturbances of a plurality of physical quantities each of which affects the beam offset (71, 72, 81) of said beam (90, 91, 92, 93, 94, 95) on said sample stage (114, 11402); at least one control unit (119, 130, 11425, 16800) configured to determine one or more compensation signals (165) for suppressing said beam offset (71, 72, 81) based on the sensor outputs (161, 162) of said plurality of sensors (121, 122, 800); the at least one control unit (119, 130, 11425, 16800) is configured to provide control signals to the beam source (111, 11412), the beam deflection unit (112, 11417), and the precursor gas source (11456, 11466, 11476, 11450, 11460, 11470, 11452, 11462, 11472) for performing electron beam induced manipulation of a sample (11110) attached to the sample stage (113, 11402); A charged particle beam repair device (100, 11120, 11410, 161001), wherein the at least one control unit (119, 130, 11425, 16800) is configured to supply the one or more compensation signals (165) to at least one of the beam source (111, 11412), the beam deflection unit (112, 11417), the sample stage (114, 11402) or one or more compensation modules during the electron beam induced manipulation.

2. The charged particle beam repair device (100, 11120, 11410, 161001) of claim 1, wherein the at least one control unit (119, 130, 11425, 16800) is configured to determine a predicted component of the beam offset (71, 72, 81) based on the sensor outputs (161, 162) of the plurality of sensors (121, 122, 800), and to determine the one or more compensation signals (165) based on the predicted component of the beam offset (71, 72, 81).

3. the sensor output (161, 162) of at least one sensor of the plurality of sensors (121, 122, 800) includes respective time series data (310); The charged particle beam repair device (100, 11120, 11410, 161001) of claim 2, wherein the at least one control unit (119, 130, 11425, 16800) is configured to determine the predicted component based on an analysis of the time series data (310) of the sensor output (161, 162) of the at least one sensor among the plurality of sensors (121, 122, 800).

4. The charged particle beam repair device (100, 11120, 11410, 161001) of claim 3, wherein the analysis of the time series data (310) includes finding fingerprints (312) of one or more predetermined disturbance events (311) in the time series data (310).

5. the at least one control unit (119, 130, 11425, 16800) is configured to selectively activate a calibration phase (6005); A charged particle beam repair device (100, 11120, 11410, 161001) as described in claim 4, wherein when operating in the calibration phase (6005), the at least one control unit (119, 130, 11425, 16800) is configured to enter the fingerprints (312) of the one or more disturbance events (311) into a repository based on at least one of identifying each repetition of the fingerprint (312) in the time series data or obtaining user input data indicating each one of the one or more disturbance events (311).

6. the at least one control unit (119, 130, 11425, 16800) is configured to selectively activate a calibration phase (6005); A charged particle beam repair device (100, 11120, 11410, 161001) as described in claim 4 or 5, wherein when operating in the calibration phase (6005), the at least one control unit (119, 130, 11425, 16800) is configured to train the predictive model based on the time series data (310) measured during the calibration phase (6005) to find the fingerprint (312), thereby enabling the predictive model to determine the predictive component.

7. A charged particle beam repair device (100, 11120, 11410, 161001) as described in any one of claims 1 to 6, wherein the at least one control unit (119, 130, 11425, 16800) is further configured to predict the accuracy of operation of the charged particle beam repair device (100, 11120, 11410, 161001) during a prediction period based on at least one of the sensor output (161, 162) or the one or more compensation signals (165).

8. A charged particle beam repair device (100, 11120, 11410, 161001) according to any one of claims 1 to 7, wherein the at least one control unit (119, 130, 11425, 16800) is configured to determine the one or more compensation signals (165) based on cross-dependencies between the plurality of disturbances.

9. A charged particle beam repair device (100, 11120, 11410, 161001) according to any one of claims 1 to 8, wherein the at least one control unit (119, 130, 11425, 16800) is configured to determine the one or more compensation signals (165) based on a pre-trained algorithm.

10. A charged particle beam repair device (100, 11120, 11410, 161001) according to any one of claims 1 to 9, wherein the at least one control unit (119, 130, 11425, 16800) is configured to determine the one or more compensation signals based on a pre-parameterized functional dependency.

11. A charged particle beam repair device (100, 11120, 11410, 161001) according to any one of claims 1 to 10, wherein the at least one control unit (119, 130, 11425, 16800) is configured to determine the one or more compensation signals (165) using a look-up table linking the sensor output (161, 162) to the one or more compensation signals.

12. A charged particle beam repair device (100, 11120, 11410, 161001) according to any one of claims 1 to 11, wherein the plurality of physical quantities are selected from the group consisting of acoustic vibration, vibration, pressure, humidity, temperature, laminar flow, turbulent flow, differential quantity, rate of change of physical quantity, vector quantity, and scalar quantity.

13. The charged particle beam repair device (100, 11120, 11410, 161001) according to any one of claims 1 to 12, wherein the plurality of sensors (121, 122, 800) includes at least one sensor for measuring a temperature or a pressure of a cooling liquid.

14. A charged particle beam repair device (100, 11120, 11410, 161001) as described in any one of claims 1 to 13, wherein at least one of the plurality of sensors (121, 122, 800) is arranged inside a vacuum chamber (110) of the charged particle beam repair device (100, 11120, 11410, 161001).

15. A charged particle beam repair device (100, 11120, 11410, 161001) as described in any one of claims 1 to 14, wherein the plurality of sensors (121, 122, 800) includes at least one sensor for measuring a pressure difference or a temperature difference between two or more components of the charged particle beam repair device (100, 11120, 11410, 161001).

16. A charged particle beam repair device (100, 11120, 11410, 161001) as described in any one of claims 1 to 15, wherein the plurality of disturbances are selected from the group consisting of direct disturbances that affect the beam offset (71, 72, 81) by deflecting the beam, and indirect disturbances that affect the beam offset (71, 72, 81) by affecting one or more components of the charged particle beam repair device (100, 11120, 11410, 161001).

17. The charged particle beam repair device (100, 11120, 11410, 161001) according to any one of claims 1 to 16, wherein the beam offset (71, 72, 81) comprises at least one of a position offset (71, 72, 81) or a focus offset (71, 72) of the beam.

18. A charged particle beam repair device (100, 11120, 11410, 161001) according to any one of claims 1 to 17, wherein the at least one control unit (119, 130, 11425, 16800) is configured to monitor the sensor output (161, 162) of at least one sensor of the plurality of sensors (121, 122, 800) or a further sensor output (161, 162) of at least one further sensor, and selectively blank the beam based on the monitoring.

19. A charged particle beam repair device (100, 11120, 11410, 161001) as described in any one of claims 1 to 18, wherein the at least one control unit (119, 130, 11425, 16800) is configured to provide the one or more compensation signals (165) while the charged particle beam repair device (100, 11120, 11410, 161001) is operating in a manipulation mode which includes repairing or modifying semiconductor devices on a wafer attached to the sample stage (114, 11402).

20. 1. A charged particle beam device (100, 11120, 11410, 161001) comprising a beam source, a beam deflection unit (112, 11417), and a sample stage (114, 11402), wherein the beam deflection unit (112, 11417) is configured to deflect a beam emanating from the beam source to position the beam on the sample stage (114, 11402), and wherein the charged particle beam device (100, 11120, 11410, 161001) comprises: a plurality of sensors (121, 122, 800) configured to measure a plurality of disturbances of a plurality of physical quantities each of which affects the beam offset (71, 72, 81) of said beam (90, 91, 92, 93, 94, 95) on said sample stage (114, 11402); - a charged particle beam device (100, 11120, 11410, 161001) including at least one control unit (119, 130, 11425, 16800) configured to determine, based on the sensor outputs (161, 162) of the plurality of sensors (121, 122, 800), metadata indicative of one or more compensation operations for suppressing the beam offset (71, 72, 81) in image data acquired by the charged particle beam device operating in imaging mode, and to store the metadata in association with the image data.

21. 1. A method of manipulating a sample (11110) attached to a sample stage of a charged particle beam repair device (100, 11120, 11410, 161001), the charged particle beam repair device including a beam source, a beam deflection unit, a precursor gas source, and a sample stage, the beam deflection unit configured to deflect a beam of charged particles emanating from the beam source to position the beam on the sample stage; - acquiring sensor outputs of a plurality of sensors of the charged particle beam repair device, the plurality of sensors measuring a plurality of disturbances of a plurality of physical quantities each affecting a beam offset of the beam on the sample stage; determining one or more compensation signals for suppressing the beam offset based on the sensor outputs of the plurality of sensors; - supplying control signals to the beam source, the beam deflection unit and the precursor gas source for performing electron beam induced manipulation of the sample; - supplying said one or more compensation signals to at least one of said beam source, said beam deflection unit, said sample stage or one or more compensation modules during said electron beam induced manipulation.

22. 22. The method of claim 21, performed by the control unit of the charged particle beam repair device of claim 1.

23. 1. A method for post-processing image data acquired by a charged particle beam device including a beam source, a beam deflection unit, and a sample stage, the beam deflection unit being configured to deflect a beam of charged particles emanating from the beam source in order to position the beam on the sample stage; - acquiring sensor outputs from a plurality of sensors of the charged particle beam device, the plurality of sensors measuring a plurality of disturbances of a plurality of physical quantities each affecting a beam offset of the beam on the sample stage; determining metadata indicative of one or more compensation actions for suppressing the beam offset in image data acquired by the charged particle beam device operating in an imaging mode based on the sensor outputs of the plurality of sensors; - post-processing said image data based on said metadata and in accordance with said one or more compensation operations.

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