Deflector for charged particle beam device, deflection system, charged particle beam device and method of manufacturing deflector

Abstract

A deflector for a charged particle beam device is described. And a deflector having an axis and configured to deflect the charged particle beam in a direction perpendicular to the axis, the deflector comprising a plurality of flat coils, the plurality of flat coils comprising two pairs of flat coils, where the two pairs of flat coils are arranged on opposite sides about the axis of the deflector.

Description

Technical Field

[0001] Embodiments described herein relate to a deflector for deflecting a charged particle beam in a charged particle beam device, such as an electron microscope, in particular a scanning electron microscope (SEM). In addition, embodiments of the present disclosure relate to a deflection system, a charged particle beam device, and a method of manufacturing a deflector. Background Art

[0002] Modern semiconductor technology places high demands on structuring and detection of samples at nanometer or even sub-nanometer scales. Micrometer and nanometer scale process control, inspection or structuring are often accomplished with charged particle beams (e.g., electron beams) that are generated, shaped, deflected and focused in charged particle beam equipment (such as electron microscopes or electron beam pattern generators). For inspection purposes, charged particle beams provide excellent spatial resolution compared to, for example, photon beams.

[0003] Equipment using charged particle beams, such as scanning electron microscopes (SEMs), has many functions in multiple industrial fields, including but not limited to inspection of electronic circuits, exposure systems for photolithography, detection systems, defect detection tools, and test systems for integrated circuits. In such particle beam systems, a fine beam probe with a high current density can be used. For example, in the case of a SEM, a primary electron beam generates signal particles, such as secondary electrons (SE) and / or backscattered electrons (BSE) that can be used for imaging and / or inspecting samples.

[0004] In charged particle beam equipment, deflectors are often used to deflect the charged particles relative to the optical axis. For example, conventional deflectors use saddle coils, toroidal coils or more complex wiring to deflect the particle beam. However, it remains challenging to provide deflectors to reliably inspect and / or image samples with good resolution and small aberrations. Reliable and reproducible production of complex deflection systems is challenging, resulting in significant deviations between individual deflectors.

[0005] In view of the above, it would be beneficial to provide an improved deflector, an improved deflection system, an improved charged particle beam apparatus and an improved method of manufacturing a deflector. Summary of the invention

[0006] In view of the above, a deflector for deflecting a charged particle beam in a charged particle beam device, a deflection system, a charged particle beam device and a method for manufacturing a deflector are provided. Further advantages, features, aspects and details that can be combined with the embodiments described herein are apparent from the dependent claims, the description and the drawings.

[0007] According to one embodiment, a deflector for a charged particle beam device is provided. The deflector has an axis and is configured to deflect a charged particle beam in a direction perpendicular to the axis. The deflector includes a plurality of flat coils, the plurality of flat coils including two pairs of flat coils, wherein the two pairs of flat coils are arranged on opposite sides around the axis of the deflector.

[0008] According to one embodiment, a deflection system for a charged particle beam device is provided. The deflection system is configured to deflect a charged particle beam of the charged particle beam device relative to an optical axis. The deflection system includes a plurality of deflectors, each of the plurality of deflectors having an axis and configured to deflect the charged particle beam in a direction perpendicular to the axis. Each deflector includes a plurality of flat coils, the plurality of flat coils including two pairs of flat coils, wherein the two pairs of flat coils are arranged on opposite sides around the axis of the deflector.

[0009] According to one embodiment, a charged particle beam device is provided. The charged particle beam device includes a deflection system, which is configured to deflect a charged particle beam of the charged particle beam device relative to an optical axis. The deflection system includes a plurality of deflectors for the charged particle beam device, each of the plurality of deflectors having an axis and configured to deflect the charged particle beam in a direction perpendicular to the axis. Each deflector includes a plurality of flat coils, the plurality of flat coils including two pairs of flat coils, wherein the two pairs of flat coils are arranged on opposite sides around the axis of the deflector.

[0010] According to one embodiment, a method of manufacturing a deflector for a charged particle beam device is provided. The method comprises arranging four flat coils as two pairs of flat coils of the deflector around an axis of the deflector, wherein the two pairs of flat coils are arranged on opposite sides around the axis. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Therefore, in order that the manner in which the above-described features of the present disclosure may be understood in detail, a more particular description briefly summarized above may be had by reference to the embodiments. The accompanying drawings relate to one or more embodiments and are described below.

[0012] Figure 1 Illustrated is a schematic diagram of a charged particle device according to embodiments described herein.

[0013] Figure 2a and Figure 2b Each illustrates a schematic diagram of a deflector according to an embodiment of the present disclosure.

[0014] Figure 3 The arrangement of flat coils in a deflector according to an embodiment of the present disclosure is schematically shown.

[0015] Figure 4A further arrangement of flat coils in a deflector according to embodiments described herein is schematically shown.

[0016] Figure 5 A deflection system with multiple deflectors according to an embodiment of the present disclosure is schematically shown.

[0017] Figure 6 A diagram showing beam deflection along an optical axis using a deflection system is illustrated in accordance with an embodiment of the present disclosure.

[0018] Figure 7 Illustrated is a schematic diagram of a charged particle device with a deflection system according to embodiments described herein.

[0019] Figure 8 A flow chart showing a method of manufacturing a deflector according to an embodiment of the present disclosure is illustrated. DETAILED DESCRIPTION

[0020] Reference will now be made in detail to various embodiments, one or more examples of which are shown in the drawings. In the following description of the drawings, like reference numerals refer to like parts. Generally, only the differences with respect to various embodiments are described. Each example is provided by way of explanation and is not intended to be limiting. In addition, features shown or described as part of one embodiment may be used in other embodiments or used in conjunction with other embodiments to produce further embodiments. The description is intended to include such modifications and variations.

[0021] Embodiments of the present disclosure provide a deflector for a charged particle beam device, wherein the deflector comprises a flat coil. The flat coil can be easier to manufacture and / or manufactured with lower tolerances than deflectors comprising other types of coils (such as saddle coils or toroidal coils). In an embodiment, the flat coils can be arranged independently to reduce aberrations. In an embodiment of the present disclosure, providing a deflector based on a flat coil can reduce production costs, reduce aberrations, improve the performance of beam separation between a primary charged particle beam and a signal charged particle beam, and / or improve matching between manufactured charged particle beam devices.

[0022] Figure 1 1 is a schematic diagram of a charged particle beam device 100. Specifically, the charged particle beam device 100 can be configured to inspect and / or image a sample 10 or a portion of a sample. The charged particle beam device 100 includes a column 102. The column 102 can provide a vacuum enclosure so that the charged particle beam travels under a vacuum. The beam optical components of the charged particle beam device 100 can be placed in a vacuum chamber of the column 102, which can be evacuated. The vacuum can facilitate the propagation of the charged particle beam from the charged particle beam source 104 toward the sample stage 130, for example, along the optical axis 12. The charged particle beam can hit the sample at a sub-atmospheric pressure, for example, less than 10-3 mbar pressure or less than 10 -5 Pressure in millibars.

[0023] The charged particle beam device 100 includes a charged particle beam source 104. The charged particle beam source can be configured to emit a charged particle beam. The charged particle beam can be an electron beam. The charged particle beam can propagate along an optical axis 12. The charged particle beam device 100 further includes a sample stage 130. The objective lens 110 focuses the charged particle beam (i.e., a primary charged particle beam) on the sample 10. The sample 10 can be placed on the sample stage 130.

[0024] The condenser lens 106 or a condenser lens system including one or more condenser lenses can be arranged downstream of the charged particle beam source 104. The condenser lens system can collimate the charged particle beam propagating toward the objective lens 110. In addition, an electrode or a tube (not shown) configured as an accelerating beam can be provided. The electrode or tube can be provided at a high potential. For example, the high potential can be a high positive potential relative to the charged particle beam source to accelerate the electron beam. The electrode or tube can provide an accelerating section for accelerating the electron beam, for example, accelerating to an electron energy of 5keV or higher. The electron can first be accelerated by an extractor electrode arranged on a positive potential relative to the emission tip of the charged particle beam source 104. The electrode or tube can provide further beam acceleration. In some embodiments, charged particles (for example, electrons) are accelerated to an electron energy of 10keV or greater, 30keV or greater, or even 50keV or greater. The high electron energy in the column can reduce the negative impact of electron-electron interaction. The high beam energy in the charged particle beam device can improve imaging resolution.

[0025] The charged particle beam device 100 may include one or more charged particle detectors, in particular two or more charged particle detectors, such as two or more electron detectors. According to the embodiments described herein, an on-axis detector 122 may be provided. Additionally or alternatively, an off-axis detector 123 may be provided. The on-axis detector and / or the off-axis detector may detect signal particles emitted or released from the sample 10. When a charged particle beam hits the sample, the signal electron is emitted or released from the sample. According to different operating modes, the charged particle detectors may each detect high-energy signal electrons or low-energy signal electrons. For example, high-energy signal electrons may be backscattered electrons (BSE), and low-energy signal electrons may be secondary electrons (SE). According to different operating modes, signal electron filtering depending on the energy of the signal electrons may be provided.

[0026] According to embodiments that can be combined with other embodiments described herein, the column 102 includes a deflection system 140 as described herein. In particular, according to embodiments of the present disclosure, the deflection system can include one or more deflectors. The deflector can deflect the charged particle beam relative to the optical axis 12. For example, in Figure 1 In the embodiment of the present invention, the deflection system comprises a plurality of deflectors 144. In particular, the deflection system 140 comprises a beam splitter 124 for separating the signal charged particle beam 22 from the primary charged particle beam travelling along the optical axis 12. The beam splitter 124 may comprise a deflector according to the embodiments described herein, in particular a magnetic deflector, wherein the beam deflection of the signal charged particle beam 22 away from the primary beam is caused by the signal charged particle beam travelling in an opposite direction compared to the primary charged particle beam. The beam splitter 124 may in particular direct the signal charged particle beam 22 to an off-axis detector 123, for example, as Figure 1 It is schematically shown in FIG.

[0027] An image generation unit (not shown) may be provided. The image generation unit may be configured to generate one or more images of the sample 10. The image generation unit may generate one or more images based on the signals received from the detector. The image generation unit may forward one or more images of the sample to a processing unit (not shown).

[0028] The sample stage 130 can be a movable stage. Specifically, the sample stage 130 can be movable in the Z direction (i.e., in the direction of the optical axis 12) so that the distance between the objective lens 110 and the sample stage 130 can be adjusted. By moving the sample stage 130 in the Z direction, the sample 10 can be moved to different "working distances". In addition, the sample stage 130 can also be moved in a plane perpendicular to the optical axis 12 (also referred to herein as the XY plane). By moving the sample stage 130 in the XY plane, a specified surface area of ​​the sample 10 can be moved to an area (e.g., a field of view (FOV)) below the objective lens 110, so that the specified surface area can be imaged by focusing the charged particle beam on the surface area of ​​the sample.

[0029] For example, the charged particle beam device 100 can be an electron microscope, in particular a scanning electron microscope. According to some embodiments that can be combined with other embodiments described herein, a scanning deflector (not shown) can be provided for scanning the charged particle beam, in particular scanning the charged particle beam over the surface of the sample 10 along a predetermined scanning pattern (e.g., in the X direction and / or the Y direction).

[0030] One or more surface areas of the sample 10 can be inspected and / or imaged using the charged particle beam device 100. The term "sample" as used herein may also be referred to as a "specimen" and may relate to, for example, a substrate having one or more layers or features formed thereon, a semiconductor wafer, a glass substrate, a flexible substrate (such as a web substrate), or another sample to be inspected. The sample may be subjected to one or more of the following inspections: (1) imaging the surface of the sample, (2) measuring the dimensions of one or more features of the sample, for example, in a lateral direction, i.e., in an XY plane, (3) performing critical dimension measurements and / or metrology, (4) detecting defects, and / or (5) investigating the quality of the sample.

[0031] According to an embodiment of the present disclosure, a deflector for a charged particle beam device is provided. The deflector has an axis and is configured to deflect a charged particle beam in a direction perpendicular to the axis. The deflector includes a plurality of flat coils. According to an embodiment, the plurality of flat coils include two pairs of flat coils, wherein the two pairs of flat coils are arranged on opposite sides around the axis of the deflector. For example, the deflector may be an electron beam deflector, in particular an electron beam deflector for an electron microscope, such as a scanning electron microscope. In an embodiment, the deflector is a magnetic deflector.

[0032] For example, Figure 2a and Figure 2b A deflector 240 is shown with two pairs 242 of flat coils 244 arranged on opposite sides around an axis 241 of the deflector 240. In an embodiment, the flat coils in each pair of flat coils are arranged closer to each other than the flat coils in the other pair of flat coils. The two pairs of flat coils can be held in place by supports (not shown). The supports can be made of a non-magnetic material. In some embodiments, the supports can allow for the fixation of individually positioned flat coils 244 as described herein.

[0033] In some embodiments, the flat coil 244 may be surrounded by a housing 246 in a circumferential direction around the axis 241, the housing 246 comprising or made of a metal having a high magnetic permeability (e.g., mu-metal). The housing 246 may be provided to contain and / or increase the magnetic field provided by the flat coil 244. For example, the housing 246 may include a tubular structure, such as Figure 2a and Figure 2b shown.

[0034] According to embodiments described herein, the flat coil comprises one or more windings. The or each winding may be wound substantially in a flat plane, wherein the windings are in the same flat plane or in parallel flat planes. The flat coil may have a plurality of winding layers, in particular wherein each winding layer is provided at least substantially in one of a plurality of parallel flat planes. It should be understood that the winding may be considered to be substantially in one flat plane even if the wire of the winding is led from one plane to another or the next plane.

[0035] In some embodiments, the flat coils 244 of the two pairs 242 of flat coils may have a substantially rectangular or square shape. In particular, it will be appreciated that the substantially rectangular or square shaped flat coils may have rounded corners, in particular due to the winding of the wires of the flat coils. The flat coils may be arranged in the deflector so that the edge of the first flat coil in each pair of flat coils is at least substantially parallel to the edge of the second flat coil in the pair of flat coils. In some embodiments, each of the two pairs of flat coils may have at least one edge, in particular two edges, oriented at least substantially parallel to the axis of the deflector. Each flat coil may have another edge in a flat plane perpendicular to the axis, and in particular have yet another edge in another flat plane perpendicular to the axis. In an embodiment, the two pairs of flat coils may be provided by four flat coils of the same size, in particular four identical flat coils. Each pair of flat coils may be arranged so that the flat planes of the two flat coils are inclined relative to each other. Thereby, a pair of flat coils may advantageously approximate a saddle shape using flat coils.

[0036] In an embodiment, the axis 241 of the deflector 240 extends through the area between the two pairs 242 of flat coils, in particular through the central area between the two pairs 242 of flat coils. The axis 241 may be at least substantially parallel to the flat planes of the flat coils 244 in the two pairs 242 of flat coils. The deflector 240 may be configured to be arranged in a charged particle beam device such that the axis 241 is at least substantially parallel to the optical axis of the charged particle beam device.

[0037] In some embodiments, the magnetic axes of the flat coils of the two pairs of flat coils are arranged in a direction at least substantially radial with respect to the axis. The magnetic axis of the flat coil extends perpendicular to the flat plane of the flat coil and in particular passes through the flat coil in the center, more particularly through an opening surrounded by one or more windings of the flat coil. According to some embodiments, which can be combined with other embodiments, each pair of the two pairs of flat coils comprises a first flat coil and a second flat coil. The flat coils of the two pairs of flat coils can be arranged such that the flat planes of the respective first flat coils are at least substantially parallel and such that the flat planes of the respective second flat coils are at least substantially parallel. In particular, the magnetic axes of the first flat coils can be parallel and in particular at least substantially collinear, and / or the further magnetic axes of the second flat coils can be parallel and in particular at least substantially collinear. In some embodiments, the axis of the deflector as mentioned herein, about which the two pairs of flat coils are arranged, can be perpendicular to the magnetic axis of the flat coil and in particular pass through the intersection between the magnetic axes of the first flat coil and the second flat coil.

[0038] For example, Figure 3 The arrangement of the flat coils in the deflector 340 according to an embodiment of the present disclosure is illustrated. The deflector 340 includes two pairs 342 of flat coils, each pair including a first flat coil 351 and a second flat coil 352. The magnetic axis 358 of the first flat coil 351 and the further magnetic axis 359 of the second flat coil 352 are arranged substantially perpendicular to the axis 341 of the deflector. Specifically, the axis 341 may pass through the intersection between the magnetic axis 358 and the further magnetic axis 359.

[0039] According to some embodiments, which can be combined with other embodiments described herein, each of the two pairs of flat coils comprises a first flat coil and a second flat coil. The center positions of the first flat coil and the second flat coil can be arranged at an angular distance of at least 45 degrees in the circumferential direction around the axis, in particular at an angular distance of at least 50 degrees or at least 55 degrees, and / or at an angular distance of at most 75 degrees in the circumferential direction around the axis, in particular at a maximum of 70 degrees or at most 65 degrees. For example, the first flat coil and the second flat coil can be arranged so that the respective center positions of the flat coils are at an angular distance of about 60 degrees around the axis. See Figure 3 The first flat coil 351 and the second flat coil 352 of each of the two pairs 342 are arranged so that the center positions of the flat coils are at an angular distance 354 of 60 degrees in the circumferential direction around the axis 341 of the deflector 340. For example, the first flat coil 351 and the second flat coil 352 may be arranged at 60 degrees to avoid the hexapole field.

[0040] In some embodiments, which can be combined with other embodiments described herein, each of the two pairs of flat coils extends over an angular interval of at least 30 degrees, in particular over an angular interval of at least 40 degrees, at least 45 degrees or at least 50 degrees, and / or over an angular interval of at most 75 degrees, in particular over at most 70 degrees or at most 65 degrees, in the circumferential direction around the axis. For example, each flat coil may extend over an angular interval of approximately 59 degrees in the circumferential direction around the axis. See Figure 3 , each of the first flat coil 351 and the second flat coil 352 of the two pairs 342 of flat coils extends over an angular interval 356 of 59 degrees (angles not drawn to scale).

[0041] According to an embodiment, the first flat coil and the second flat coil are arranged adjacent to each other in a circumferential direction around the axis, in particular in contact with each other. In an embodiment, the first flat coil and the second flat coil are spaced apart from each other in a circumferential direction around the axis. Specifically, the first flat coil and the second flat coil may be spaced apart from each other by less than 10 degrees, in particular less than 5 degrees or less than 3 degrees, and / or spaced apart from each other by more than 0.5 degrees, in particular more than 0.75 degrees, in the circumferential direction. For example, the first flat coil and the second flat coil may be spaced apart by between 0.5 degrees and 3 degrees, in particular between 1 degree and 2 degrees. The flat coils may be arranged such that the flat coils do not overlap in the circumferential direction around the axis. For example, the first flat coil 351 and the second flat coil 352 in a pair 342 of flat coils may be spaced apart by an angular interval 357 of approximately 1 degree in the circumferential direction, for example, as Figure 3 (angles are not drawn to scale). In some embodiments, the first coil and the second coil may be spaced apart by approximately 1 mm.

[0042] In some embodiments, the flat coils of the two pairs of flat coils may be arranged symmetrically around the central axis. In further embodiments that may be combined with other embodiments of the present disclosure, the two pairs of flat coils are arranged on opposite sides around the central axis of the two pairs of flat coils, wherein the flat coils of the two pairs of flat coils are arranged asymmetrically relative to the central axis. Additionally or alternatively, the flat coils may be arranged reflection asymmetrically relative to a plane along the central axis, and / or may be arranged center asymmetrically relative to a center point of the flat coils. In an embodiment, one or more flat coils may be displaced by a radial displacement ΔR relative to a symmetrical arrangement around the central axis. In one example, the radial displacement may be less than 2 mm, in particular less than 1.5 mm or less than 1.3 mm, and / or greater than 0.1 mm, in particular greater than 0.2 mm or greater than 0.5 mm. In particular, the radial distances of the flat coils from the central axis may be different. The asymmetrical arrangement of the flat coils may be used to compensate for astigmatism of a charged particle beam. In particular, astigmatism correction may be improved for deflectors having other types of coils, such as saddle coils or toroidal coils. More specifically, the flat coils in the two pairs of flat coils can be individually displaced relative to the central axis to compensate for astigmatism. The compensation (or correction) of astigmatism by the arrangement of the flat coils of the deflector described herein can be understood as pre-compensation (or pre-correction) of astigmatism to reduce astigmatism in the electron beam column. The total astigmatism of the electron beam provided by the electron beam column may depend on, for example, the deflection and / or operating mode used. In addition to the deflector or deflection system described herein, the electron beam column according to an embodiment may include an astigmatism detector, such as a conventional astigmatism detector, in order to finely correct the astigmatism. In an embodiment, the radial displacement ΔR may vary for different electron beam columns. For example, the radial displacement may depend on the amount of deflection provided by the electron beam column.

[0043] In some embodiments, two of the two pairs of flat coils can be displaced by a radial displacement ΔR toward the axis, wherein the two flat coils are adjacent flat coils in a circumferential direction around the axis and belong to different pairs of the two pairs of flat coils. The other two of the two pairs of flat coils can be displaced by a radial displacement ΔR away from the axis. Specifically, the asymmetric arrangement can introduce a quadrupole component into the magnetic field of the deflector. The quadrupole component can be provided to compensate for astigmatism.

[0044] For example, Figure 4 The diagram shows an asymmetric arrangement of the first flat coil 351 and the second flat coil 352 relative to the axis 341. Specifically, in the image plane shown perpendicular to the axis 341, the flat coils are arranged relative to Figure 4 The intersection of the image plane and the axis 314 is arranged in an asymmetric manner. Figure 4Compared to the dotted line 450 in FIG. 3 , in each of the two pairs 342 of flat coils, one of the flat coils is displaced by a radial displacement ΔR toward the axis 341, while the other of the flat coils is displaced by a radial displacement ΔR away from the axis 341. The asymmetric arrangement introduces a quadrupole component into the magnetic field of the deflector 340. It will be appreciated that in further embodiments, not all of the flat coils of the deflector may be positioned with a radial displacement relative to the axis 341. For example, in some embodiments, only two of the flat coils of the deflector may be radially displaced relative to the axis.

[0045] According to an embodiment, the distance of each flat coil of the two pairs of coils from the axis of the deflector is greater than 18 mm, in particular greater than 19 mm, and / or less than 30 mm, in particular less than 27 mm or less than 25 mm. For example, the distance of the flat coil from the axis of the deflector may be about 21 mm, in particular plus or minus the individual displacement of the flat coils. Positioning the flat coils at a radial distance as described herein may provide a uniform magnetic field of the deflector. In a further embodiment, the distance of each flat coil of the two pairs of coils from the axis of the deflector may be less than 18 mm.

[0046] In an embodiment, the deflector is a one-dimensional deflector. Specifically, the deflector can be configured to deflect the charged particle beam in a direction perpendicular to the axis of the deflector. In particular, the deflector can be configured to deflect the charged particle beam in an X direction perpendicular to the axis (z axis) of the deflector. Depending on the charge of the charged particles of the charged particle beam, the direction of travel of the charged particles and the direction of the current through the flat coil of the deflector, the deflector can be configured to deflect the charged particle beam in the +X direction or the -X direction.

[0047] Deflectors according to embodiments may be easier to produce, particularly in view of the fact that flat coils are easier to manufacture than saddle coils or toroidal coils. In particular, flat coils may be produced with fewer manufacturing steps and / or within lower tolerances. The arrangement of a pair of flat coils according to embodiments may advantageously allow for individual arrangements of flat coils, particularly asymmetric arrangements, which may be used in particular for astigmatism compensation, compared to the magnetic field provided by a saddle coil. Embodiments may provide improved matching between manufactured charged particle beam devices, as tolerances in the deflector may be reduced. Embodiments may reduce adjustments regarding the matching of charged particle beam devices and thus provide easier manufacture of charged particle beam devices. In addition, the cost of a deflector based on a flat coil may be lower than the cost of a deflector based on a saddle coil or other type of coil.

[0048] According to an embodiment of the present disclosure, a deflection system for a charged particle beam device is provided. The deflection system can be configured to deflect a charged particle beam of the charged particle beam device relative to an optical axis, and the deflection system includes a plurality of deflectors according to the embodiments described herein. In some embodiments, the deflector of the deflection system can be configured as a beam splitter to separate a primary charged particle beam from a signal charged particle beam.

[0049] In some embodiments, the plurality of deflectors of the deflection system comprises at least four deflectors arranged along the optical axis, in particular precisely four deflectors according to the embodiments described herein, in particular four magnetic deflectors. In an embodiment, the plurality of deflectors comprises a first deflector, a second deflector, a third deflector and a fourth deflector arranged in this order along the optical axis. The first deflector is configured to be arranged closest to a charged particle beam source, which is configured to generate a primary charged particle beam of a charged particle beam device. The fourth deflector may be configured to be arranged closest to a sample stage of the charged particle beam device. Specifically, the fourth deflector may be configured as a beam splitter. According to some embodiments, each of the plurality of deflectors is arranged such that the respective axis of the deflector is at least substantially parallel to the optical axis of the deflection system. Specifically, the flat coils of the deflectors may arrange their magnetic axes to be at least substantially perpendicular to the optical axis of the deflection system.

[0050] For example, Figure 5 A deflection system 570 is shown that is configured to deflect a charged particle beam relative to an optical axis 12 of the deflection system 570. The deflection system 570 includes a first deflector 571, a second deflector 572, a third deflector 573, and a fourth deflector 574 arranged in this order along the optical axis 12. The deflection system 570 is configured to deflect a primary charged particle beam along a primary charged particle beam path 575. In addition, the fourth deflector 574 is configured as a beam splitter so that a signal charged particle beam path 576 is directed away from the primary charged particle beam path 575, in particular for detection by the off-axis detector 522.

[0051] According to some embodiments, a plurality of deflectors may be at least substantially arranged so that the axis of the deflector is aligned with the optical axis of the deflection system. In a further embodiment, the third deflector may be arranged so that the axis of the third deflector (particularly the central axis of the third deflector) is offset or displaced in a direction perpendicular to the optical axis. Specifically, the third deflector may be offset relative to at least one of the first deflector, the second deflector, and the fourth deflector. In an embodiment, the offset may be greater than 1 mm, particularly greater than 2 mm or greater than 3 mm, and / or less than 15 mm, particularly less than 10 mm, for example approximately 6 mm. The offset of the third deflector may be in the direction of the primary beam deflection provided by the first deflector and the second deflector. Shifting the third deflector may provide a more uniform magnetic field for the primary charged particle beam at the third deflector.

[0052] In some embodiments, the first deflector, the second deflector and / or the fourth deflector may be arranged such that the respective axes of the deflectors are at least substantially aligned with the optical axis. Figure 5 570. In the embodiment of the present invention, the first deflector 571, the second deflector 572 and the fourth deflector 574 are aligned with the optical axis 12 of the deflection system 570. The third deflector 573 is arranged with an offset 578 in the primary beam deflection direction provided by the first deflector 571 and the second deflector 572.

[0053] According to some embodiments, the two pairs of flat coils of the fourth deflector comprise four flat coils arranged asymmetrically around the axis of the fourth deflector. According to embodiments described herein, an asymmetrical arrangement may be provided, in particular with a radial displacement ΔR relative to the axis of the fourth deflector. An asymmetrical arrangement may be provided such that astigmatism of the primary charged particle beam is corrected at the fourth deflector.

[0054] Figure 6 The diagram shows that Figure 5 600 of a primary beam deflection 610 performed by a deflection system schematically shown in FIG. 600 illustrates the deflection of a primary beam, particularly an electron beam, from a charged particle beam source 604 (left) toward a sample (right). The deflection is illustrated in the X direction along the optical axis (Z axis), wherein the X direction is a direction perpendicular to the optical axis. The diagram 600 specifically illustrates the positions 621, 622, 623, and 624 of a first deflector, a second deflector, a third deflector, and a fourth deflector, respectively.

[0055] According to some embodiments and Figure 6 Specifically shown in , the first deflector and the second deflector can be configured to deflect the charged particle beam away from the optical axis. The third deflector and the fourth deflector can be configured to deflect the charged particle beam toward the optical axis or to align the charged particle beam with the optical axis. Figure 6, arrow 612 shows the apparent beam path from the charged particle beam source 604 to a midpoint 626 between the positions 622, 623 of the second and third deflectors. In some embodiments, deflecting a primary charged particle beam so that the beam appears to come from a charged particle beam source may be advantageous for beam conditioning in a column of a charged particle beam device. A deflection system using a flat coil as described herein may advantageously provide low astigmatism and / or a small virtual spot size for a charged particle beam, particularly even when the amount of deflection of the charged particle beam is greater than that of a conventional system.

[0056] According to an embodiment of the present disclosure, there is provided a charged particle beam device comprising a deflection system as described herein. The deflection system may be arranged in a column of the charged particle beam device, in particular between a charged particle beam source and an objective lens of the column. The charged particle beam device may comprise any of the further features described herein, in particular in combination with Figure 1 Describe the characteristics of a charged particle beam device.

[0057] Figure 7 A charged particle beam apparatus 700 is shown having a column 702 having a Figure 5 The deflection system 770 is shown arranged along the optical axis 12 of the charged particle beam device 700. In particular, the deflection system 770 having a first deflector 771, a second deflector 772, a third deflector 773 and a fourth deflector 774 is arranged between the charged particle beam source 704 and the objective lens 710 of the charged particle beam device 700. The fourth deflector 774 is used as a beam splitter to separate the primary charged particle beam 775 from the signal charged particle beam 776. The signal charged particle beam 776 from the sample 10 placed on the sample stage 730 is guided to the off-axis detector 722 by the fourth deflector 774 and the third deflector 773. It should be understood that the charged particle beam device 700 may include additional components described herein, such as an on-axis detector, wherein Figure 7 These additional components are omitted for clarity.

[0058] According to some embodiments, which may be combined with other embodiments described herein, a charged particle beam device may include a controller having a processor and a memory, the memory storing instructions which, when executed by a process, cause the device and in particular the deflection system to operate according to any of the embodiments described herein. For example, the charged particle beam device may be controlled to image and / or inspect a sample. In some embodiments, a plurality of deflectors of a deflection system of the device may be operated and / or controlled individually. In a further embodiment, two or more of the plurality of deflectors of the deflection system may be controlled together, in particular a current passing through the two or more deflectors. For example, in a deflection system according to an embodiment, a first deflector and a second deflector may be controlled together, and / or a third deflector and a fourth deflector may be controlled together.

[0059] Figure 7 The controller 780 illustrated in the example controls the operation of the charged particle beam device 700 and in particular the operation of the deflection system 770. The controller 780 may include a central processing unit (CPU), a memory, and, for example, a support circuit. To facilitate the control of the charged particle beam device, and in particular the control of the deflection system 770, the CPU may be one of any form of general purpose computer processor that may be used to control various SEM components. The memory is coupled to the CPU. The memory or computer readable medium may be one or more readily available memory devices, such as random access memory, read-only memory, hard disk, or any other form of local or remote digital storage. The support circuit may be coupled to the CPU for supporting the processor in a conventional manner. The circuit includes a cache, a power supply, a clock circuit, an input / output circuit system, and related subsystems, etc. The inspection process instructions are typically stored in the memory as software routines, which are typically referred to as recipes. The software routines may also be stored and / or executed by a second CPU, which is located away from the hardware controlled by the CPU. When executed by the CPU, the software routines convert the general purpose computer into a special purpose computer (controller) that controls the operation of the device, in particular so that control of the deflection system of the device can be provided. Although the operations of the controller may be discussed as being implemented as software routines, some of the operations may be performed in hardware and performed by a software controller. Thus, the operations may be implemented in software executed on a computer system, in hardware as an application specific integrated circuit or other type of hardware implementation, or in a combination of software and hardware.

[0060] According to an embodiment of the present disclosure, a method for manufacturing a deflector for a charged particle beam device is provided. The method includes arranging four flat coils around an axis of the deflector as two pairs of flat coils of the deflector, wherein the two pairs of flat coils are arranged on opposite sides around the axis. The four flat coils can be arranged according to the embodiments described herein. According to an embodiment of the present disclosure, the arranged flat coils can form a deflector. In some embodiments, the four flat coils can be arranged symmetrically around the axis.

[0061] In a further embodiment, arranging the four flat coils comprises arranging the four flat coils asymmetrically around the axis. In particular, the method may comprise determining an astigmatism to be corrected by the deflector. The astigmatism to be corrected may be an astigmatism introduced in a column of a charged particle beam device by a device generating and / or interacting with the charged particle beam (e.g., a further deflector arranged along the primary beam path before the deflector). Additionally or alternatively, the astigmatism to be corrected may comprise an astigmatism introduced by the deflector itself. The astigmatism to be corrected may be determined, for example, by measurements (such as measurements in a charged particle beam device), and / or by simulations (such as ray tracing of multiple trajectories through a column of a charged particle beam device or through a deflection system (such as the deflection system described herein)). The method may further comprise determining a position and in particular an orientation of the four flat coils relative to the axis to correct the determined astigmatism. For example, the position and / or orientation may be determined by measurements and / or simulations. The four flat coils may be arranged at a determined position and in particular with a determined orientation to at least partially correct the astigmatism.

[0062] For example, Figure 8 A flow chart of a method 800 of manufacturing a deflector is shown. At 802, an astigmatism to be corrected by the deflector can be determined. At 804, positions and orientations of four flat coils arranged in two pairs on opposite sides around an axis can be determined so that the deflector can at least partially correct the determined astigmatism. At 806, the four flat coils are arranged as two pairs of flat coils around the axis on opposite sides around the axis of the deflector. Specifically, the four flat coils can be positioned and oriented according to the determined positions and orientations to at least partially correct the determined astigmatism.

[0063] In some embodiments, the manufactured deflector can be used in a method of manufacturing a deflection system, in particular a deflection system according to embodiments described herein. A deflector manufactured to correct for astigmatism can be used specifically as a fourth deflector in a deflector system as described herein. In some embodiments, the manufactured deflection system can be used in a method of manufacturing a charged particle beam device, in particular a charged particle beam device according to embodiments described herein.

[0064] In another aspect of the present disclosure, a deflection system for a charged particle beam device and a charged particle beam device including such a deflection system are provided. The deflection system can be configured to deflect the charged particle beam of the charged particle beam device relative to the optical axis of the charged particle beam device. In an embodiment, the deflection system includes at least four deflectors, in particular four accurate deflectors. In an embodiment, the deflector is a magnetic deflector. The deflector includes a first deflector, a second deflector, a third deflector and a fourth deflector, wherein the deflectors are specifically arranged in this order between the charged particle beam source and the objective lens of the charged particle beam device. The deflector according to this aspect is specifically not limited to a deflector including a flat coil as described herein, but may additionally or alternatively include, for example, one or more deflectors having a saddle coil or having one or more other types of coils. The deflection system and charged particle beam device according to this aspect may include any of the other features of the deflection system or charged particle beam device of the present disclosure. The arrangement of the deflector as described in this aspect may be combined with other aspects and embodiments of the deflection system or charged particle beam apparatus of the present disclosure.

[0065] According to an embodiment, each of the first deflector, the second deflector, the third deflector and the fourth deflector has an axis according to the embodiments described herein. In an embodiment, the first deflector, the second deflector and the fourth deflector are arranged coaxially with the optical axis of the charged particle beam device. In an embodiment, the third deflector is positioned so that the deflector axis is arranged off-axis relative to the optical axis, in particular the deflector axis of the third deflector is offset relative to the optical axis. Specifically, only the third deflector of the at least four deflectors can be arranged offset relative to the optical axis. The deflector axis of the third deflector can be oriented parallel to the optical axis. The arrangement of the at least four deflectors and in particular the offset of the third deflector can be provided according to other embodiments of the deflection system or the charged particle beam device described herein, for example, as combined with Figures 5 to 7 Described. Specifically, the offset of the third deflector can be provided in a direction perpendicular to the optical axis. The offset can be greater than 1 mm, in particular greater than 2 mm or greater than 3 mm, and / or less than 15 mm, in particular less than 10 mm, for example about 6 mm. The first deflector and the second deflector can be configured to deflect the primary charged particle beam at least substantially toward the central area of ​​the third deflector. The offset of the third deflector can provide a uniform magnetic field for deflecting the primary charged particle beam at the third deflector.

[0066] Embodiments of the present disclosure may provide advantages specifically in the manufacture and / or operation of deflectors, deflection systems, and charged particle beam devices. For example, flat coils may allow for easier manufacture of deflectors compared to deflectors using other types of coils. In particular, the flat coils may be accurately manufactured with low tolerances. Manufacturing costs may be reduced. The use of two pairs of flat coils may provide flexibility in positioning the flat coils, particularly by placing the flat coils individually. For example, the flat coils may be advantageously positioned to pre-compensate for astigmatism. Additionally or alternatively, the coils of the deflector may be positioned to provide improved field uniformity. Embodiments may provide improved matching of charged particle beam devices in manufacture. In addition, the embodiments described herein may provide improved performance in beam separation and / or charged particle beam characteristics, such as improved performance with respect to astigmatism and / or virtual spot size.

[0067] In this disclosure, multiple embodiments are described, which include, among others, the following embodiments.

[0068] Embodiment 1. A deflector for a charged particle beam device, the deflector having an axis and configured to deflect the charged particle beam in a direction perpendicular to the axis, the deflector comprising: a plurality of flat coils, including two pairs of flat coils, wherein the two pairs of flat coils are arranged on opposite sides around the axis of the deflector.

[0069] Embodiment 2. A deflector as described in embodiment 1, wherein each of the two pairs of flat coils comprises a first flat coil and a second flat coil, wherein the center positions of the first flat coil and the second flat coil are arranged at an angular distance of at least one of the following: at least 45 degrees in the circumferential direction around the axis, and a maximum angular distance of 75 degrees in the circumferential direction around the axis.

[0070] Embodiment 3. A deflector as described in Embodiment 1 or 2, wherein each of the two pairs of flat coils extends over at least one of an angular interval of at least 30 degrees in the circumferential direction around the axis and an angular interval of at most 75 degrees in the circumferential direction around the axis.

[0071] Embodiment 4. The deflector of any one of embodiments 1 to 3, wherein the first flat coil and the second flat coil are arranged adjacent to each other or spaced apart from each other by less than 10 degrees in a circumferential direction around the axis.

[0072] Embodiment 5. A deflector as described in any one of embodiments 1 to 4, wherein the deflector is a one-dimensional deflector.

[0073] Embodiment 6. The deflector of any one of embodiments 1 to 5, wherein the magnetic axes of the flat coils in the two pairs of flat coils are arranged in a direction at least substantially radial relative to the axis.

[0074] Embodiment 7. A deflector as described in any one of embodiments 1 to 6, wherein the two pairs of flat coils are arranged on opposite sides around a central axis of the two pairs of flat coils, and wherein the flat coils in the two pairs of flat coils are arranged asymmetrically with respect to the central axis.

[0075] Embodiment 8. The deflector of any one of embodiments 1 to 7, wherein each flat coil in the two pairs of coils is located at a distance greater than 18 mm from the axis.

[0076] Embodiment 9. A deflection system for a charged particle beam device, wherein the deflection system is configured to deflect a charged particle beam of the charged particle beam device relative to an optical axis, and the deflection system comprises a plurality of deflectors as described in any one of Embodiments 1 to 8.

[0077] Embodiment 10. A deflection system as described in Embodiment 9, wherein the plurality of deflectors include a first deflector, a second deflector, a third deflector and a fourth deflector arranged in this order along the optical axis, wherein the first deflector is configured to be arranged closest to a charged particle beam source configured to generate a primary charged particle beam of the charged particle beam device, and wherein the fourth deflector is configured to be arranged closest to a sample stage of the charged particle beam device.

[0078] Embodiment 11. A deflection system as described in Embodiment 10, wherein the third deflector is arranged so that the axis of the third deflector is offset in a direction perpendicular to the optical axis relative to at least one of the first deflector, the second deflector and the fourth deflector.

[0079] Embodiment 12. A deflection system as described in Embodiment 11, wherein the axes of the first deflector, the second deflector and the fourth deflector are at least substantially aligned with the optical axis.

[0080] Embodiment 13. The deflection system of any one of Embodiments 10 to 12, wherein the two pairs of flat coils of the fourth deflector include four flat coils arranged asymmetrically around the axis of the fourth deflector.

[0081] Embodiment 14 A charged particle beam device, comprising a deflection system as described in any one of embodiments 9 to 13.

[0082] Embodiment 15. A method for manufacturing a deflector for a charged particle beam device, the method comprising:

[0083] Four flat coils are arranged around the axis of the deflector as two pairs of flat coils of the deflector, wherein the two pairs of flat coils are arranged on opposite sides around the axis.

[0084] 16. The method of embodiment 15, wherein arranging the four flat coils comprises arranging the four flat coils asymmetrically about the axis.

[0085] While the foregoing is directed to embodiments, other and further embodiments may be devised without departing from the basic scope and the scope is determined by the claims that follow.

Claims

1. A deflector for a charged particle beam device, the deflector having an axis and being configured to deflect a charged particle beam in a direction perpendicular to the axis, the deflector comprising: A plurality of flat coils including two pairs of flat coils, wherein the two pairs of flat coils are arranged on opposite sides around the axis of the deflector.

2. The deflector according to claim 1, wherein each of the two pairs of flat coils comprises a first flat coil and a second flat coil, wherein the center positions of the first flat coil and the second flat coil are arranged at an angular distance of at least one of the following: at least 45 degrees in the circumferential direction around the axis and at most 75 degrees in the circumferential direction around the axis.

3. The deflector according to claim 1, wherein each of the two pairs of flat coils extends over at least one of an angular interval of at least 30 degrees in the circumferential direction around the axis and an angular interval of at most 75 degrees in the circumferential direction around the axis. 4 . The deflector of claim 1 , wherein the first flat coil and the second flat coil are arranged adjacent to each other or spaced apart from each other by less than 10 degrees in a circumferential direction around the axis.

5. A deflector according to any one of claims 1 to 4, wherein the deflector is a one-dimensional deflector.

6. The deflector according to any one of claims 1 to 4, wherein the magnetic axes of the flat coils in the two pairs of flat coils are arranged in a direction at least substantially radial with respect to the axis.

7. The deflector according to any one of claims 1 to 4, wherein the two pairs of flat coils are arranged on opposite sides around a central axis of the two pairs of flat coils, and wherein the flat coils in the two pairs of flat coils are arranged asymmetrically with respect to the central axis.

8. The deflector according to any one of claims 1 to 4, wherein each flat coil in the two pairs of coils is located at a distance greater than 18 mm from the axis.

9. A deflection system for a charged particle beam device, the deflection system being configured to deflect a charged particle beam of the charged particle beam device relative to an optical axis, the deflection system comprising a plurality of deflectors, each of the plurality of deflectors having an axis and being configured to deflect the charged particle beam in a direction perpendicular to the axis, each deflector comprising: A plurality of flat coils including two pairs of flat coils, wherein the two pairs of flat coils are arranged on opposite sides around the axis of the deflector.

10. The deflection yoke of claim 9, wherein each of the two pairs of flat coils comprises a first flat coil and a second flat coil, wherein center positions of the first flat coil and the second flat coil are arranged at an angular distance of at least 45 degrees in a circumferential direction around the axis and at most 75 degrees in a circumferential direction around the axis.

11. The deflection yoke of claim 9, wherein each of the two pairs of flat coils extends over at least one of an angular interval of at least 30 degrees in a circumferential direction around the axis and an angular interval of at most 75 degrees in a circumferential direction around the axis.

12. A deflection system according to any one of claims 9 to 11, wherein the plurality of deflectors include a first deflector, a second deflector, a third deflector and a fourth deflector arranged in this order along the optical axis, wherein the first deflector is configured to be arranged closest to a charged particle beam source configured to generate a primary charged particle beam of the charged particle beam device, and wherein the fourth deflector is configured to be arranged closest to a sample stage of the charged particle beam device.

13. The deflection system according to claim 12, wherein the third deflector is arranged so that the axis of the third deflector is offset in a direction perpendicular to the optical axis relative to at least one of the first deflector, the second deflector and the fourth deflector.

14. The deflection system of claim 13, wherein the axes of the first deflector, the second deflector and the fourth deflector are at least substantially aligned with the optical axis.

15. The deflection yoke of claim 12, wherein the two pairs of flat coils of the fourth deflector include four flat coils asymmetrically arranged around the axis of the fourth deflector.

16. A charged particle beam device, comprising a deflection system configured to deflect a charged particle beam of the charged particle beam device relative to an optical axis, the deflection system comprising a plurality of deflectors for the charged particle beam device, each of the plurality of deflectors having an axis and configured to deflect the charged particle beam in a direction perpendicular to the axis, each deflector comprising: A plurality of flat coils including two pairs of flat coils, wherein the two pairs of flat coils are arranged on opposite sides around the axis of the deflector.

17. The charged particle beam device according to claim 16, wherein each of the two pairs of flat coils comprises a first flat coil and a second flat coil, wherein the center positions of the first flat coil and the second flat coil are arranged at an angular distance of at least one of the following: at least 45 degrees in the circumferential direction around the axis, and at most 75 degrees in the circumferential direction around the axis.

18. The charged particle beam apparatus according to claim 16 or 17, wherein each of the two pairs of flat coils extends over at least one of an angular interval of at least 30 degrees in the circumferential direction around the axis and an angular interval of at most 75 degrees in the circumferential direction around the axis.

19. A method of manufacturing a deflector for a charged particle beam apparatus, the method comprising: Four flat coils are arranged around the axis of the deflector as two pairs of flat coils of the deflector, wherein the two pairs of flat coils are arranged on opposite sides around the axis.

20. The method of claim 19, wherein arranging the four flat coils comprises arranging the four flat coils asymmetrically about the axis.

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