Systems and methods for compensating for dispersion of a beam splitter in a single-beam or multi-beam apparatus

Abstract

Systems and methods for compensating for dispersion of a beam splitter in a single-beam or multi-beam apparatus are provided. Embodiments of the present disclosure provide a dispersion device that includes an electrostatic deflector and a magnetic deflector configured to induce beam dispersion that is set to cancel the dispersion generated by the beam splitter. The combination of the electrostatic deflector and the magnetic deflector can be used to keep the deflection angle due to the dispersion device constant as the induced beam dispersion is changed to compensate for changes in the dispersion generated by the beam splitter. In some embodiments, the deflection angle due to the dispersion device can be controlled to be zero and there is no primary beam axis change due to the dispersion device.

Description

[0001] This application is a divisional application of application number 201880048462.7, filed on 12 / 07 / 2018, having the title "System and method for compensating for dispersion of a beam splitter in a single or multiple beam apparatus". TECHNICAL FIELD

[0002] The present disclosure relates generally to the field of charged particle beam apparatuses, and more specifically to a system and method for compensating for dispersion of a beam splitter in a single or multiple beam apparatus. BACKGROUND

[0003] In the manufacturing process of integrated circuits (ICs), unfinished or finished circuit components are inspected to ensure that they are manufactured according to design and are free of defects. Inspection systems utilizing optical microscopes typically have a resolution down to a few hundred nanometers; and the resolution is limited by the wavelength of light. As the physical size of IC components continues to shrink down to sub-100 nanometers and even sub-10 nanometers, inspection systems with higher resolution compared to systems using optical microscopes are needed.

[0004] Charged particle (e.g., electron) beam microscopes (e.g., scanning electron microscopes (SEMs) or transmission electron microscopes (TEMs)) with resolutions down to less than a nanometer are used as a practical tool for inspecting IC components having feature sizes that are sub-100 nanometers. With an SEM, the electrons of a single primary electron beam or multiple primary electron beams can be focused at a probe point of a wafer under inspection. The interaction of the primary electrons with the wafer can result in one or more secondary electron beams. The secondary electron beams can include backscattered electrons, secondary electrons, or Auger electrons resulting from the interaction of the primary electrons with the wafer. The intensity of the one or more secondary electron beams can vary based on the properties of the internal and / or external structures of the wafer.

[0005] A detection device or detector can be used to determine the intensity of the secondary electron beams. The secondary electron beams can form one or more beam spots at predetermined locations on the surface of the detector. The detector can generate an electrical signal (e.g., current, voltage, etc.) representative of the detected intensity of the secondary electron beams. The electrical signal can be measured using a measurement circuit (e.g., an analog-to-digital converter) to obtain a distribution of the detected electrons. The electron distribution data collected during a detection time window in combination with corresponding scan path data of the one or more primary electron beams incident on the wafer surface can be used to reconstruct an image of the wafer structure under inspection. The reconstructed image can be used to reveal various features of the internal and / or external structures of the wafer and can be used to reveal any defects that can be present in the wafer.

[0006] In an inspection system comprising a single primary beam and a single secondary beam (single-beam apparatus), if the detector has a hole that allows the primary beam to pass through, the detector can be placed along the optical axis of the apparatus. However, the presence of the hole reduces the detection efficiency of the secondary beam and in some cases results in a dark spot in the center of the reconstructed image. A beam splitter can be used to separate the secondary beam from the primary beam and direct the secondary beam towards a detector placed off-axis. In an inspection system comprising multiple primary beams and multiple secondary beams (multi-beam apparatus), a beam splitter can be used to separate the multiple secondary beams from the multiple primary beams and direct the multiple secondary beams towards a detector placed off-axis.

[0007] The beam splitter comprises at least one magnetic deflector and therefore generates dispersion on the one or more primary beams and the one or more secondary beams. The dispersion can distort the circular probe spot of the primary beam into an elliptical shape. The dispersion can also distort the detected beam spot, resulting in a degradation of the resolution of the reconstructed image. The beam splitter also adds an associated astigmatism aberration to the primary and secondary beams. Furthermore, the deflection angle associated with the beam splitter results in a non-straight path of the primary beam. The optical elements of the single-beam or multi-beam apparatus placed between the beam source and the beam splitter need to be tilted with respect to the optical axis. The tilted arrangement and associated alignment add complexity to the apparatus. In addition, for any change in the primary beam energy, the beam splitter can be adjusted to keep the deflection angle of the primary beam constant. However, the adjustment causes an associated change in the deflection angle of the secondary beam. Uncontrolled changes in the secondary beam deflection angle can result in a decrease in the detection efficiency in single-beam and multi-beam apparatuses and can also result in cross-talk issues in multi-beam apparatuses. SUMMARY

[0008] Embodiments of the present disclosure provide systems and methods for compensating for the dispersion of a beam splitter in a single-beam or multi-beam apparatus. In some embodiments, a dispersion device is provided. The dispersion device comprises an electrostatic deflector and a magnetic deflector configured to induce a first beam dispersion of a charged particle beam of a system. The first beam dispersion is set to cancel the effect of a second beam dispersion of the beam caused by a beam splitter. The electrostatic deflector exerts a first force on the beam and the magnetic deflector exerts a second force on the beam, and the first force and the second force are substantially opposite to each other and form the first beam dispersion.

[0009] In some embodiments, a charged particle beam apparatus is provided. The charged particle beam apparatus includes a source for generating a primary charged particle beam, a first dispersion device below the source, a beam splitter below the first dispersion device, an objective lens below the beam splitter, a sample stage for supporting a sample, and a detector above the beam splitter. The primary charged particle beam is focused onto the sample through the objective lens, forming a primary detection point thereon, thereby generating a secondary charged particle beam. The beam splitter separates the primary and secondary charged particle beams such that the secondary charged particle beam is detected by the detector. The first dispersion device generates a first primary beam dispersion on the primary charged particle beam, and the beam splitter generates a second primary beam dispersion on the primary charged particle beam and a second secondary beam dispersion on the secondary charged particle beam. The first dispersion device includes a first electrostatic deflector and a first magnetic deflector that apply a first force and a second force, respectively, to the primary charged particle beam, and the first and second forces are opposite to each other and form the first primary beam dispersion, wherein the first primary beam dispersion is adjusted such that it eliminates the effect of the second primary beam dispersion on the primary detection point.

[0010] In some embodiments, a method is provided for controlling dispersion in a charged particle beam system having a beam splitter. The method includes: providing a first dispersion device in the path of a primary charged particle beam of the system; placing the first dispersion device upstream of the beam splitter; generating a first primary beam dispersion of the primary charged particle beam through the first dispersion device; and adjusting the first primary beam dispersion to eliminate the effect of a second primary beam dispersion of the primary charged particle beam caused by the beam splitter. The first dispersion device includes a first electrostatic deflector and a first magnetic deflector that apply a first force and a second force, respectively, to the primary charged particle beam, the first force and the second force being opposite to each other and forming the first primary beam dispersion.

[0011] In some embodiments, a charged particle beam apparatus is provided. The charged particle beam apparatus includes: a source configured to provide a primary charged particle beam; a source conversion unit configured to form a plurality of parallel images of the source using a plurality of sub-beams of the primary charged particle beam; a first projection system having an objective lens and configured to project the plurality of parallel images onto a sample, and thus use the plurality of sub-beams to form a plurality of primary detection points thereon; a beam splitter configured to separate the plurality of sub-beams and a plurality of secondary charged particle beams generated from the sample through the plurality of primary detection points; a detection device having a plurality of detection elements; a secondary projection system configured to focus the plurality of secondary charged particle beams onto the detection device and form a plurality of secondary detection points thereon, and the plurality of secondary detection points being detected by the plurality of detection elements; and a first dispersion device disposed upstream of the beam splitter and configured to generate a plurality of first primary beam dispersions on the plurality of sub-beams, wherein the plurality of first primary beam dispersions are adjusted to eliminate the influence of a plurality of second primary beam dispersions generated by the beam splitter on the plurality of primary detection points. The first dispersion device includes a first electrostatic deflector and a first magnetic deflector that apply a first force and a second force to each of a plurality of sub-beams, respectively, the first force and the second force being opposite to each other and forming a corresponding first primary beam dispersion.

[0012] In some embodiments, a method is provided for controlling dispersion in a charged particle beam system having a beam splitter. The method includes: providing a source conversion unit to form multiple images of a source through multiple sub-beams of a primary charged particle beam generated by the source; providing a first dispersion device in the path of the multiple sub-beams; placing the first dispersion device upstream of the beam splitter; generating multiple first primary beam dispersions of the multiple sub-beams by the first dispersion device; and adjusting the multiple first primary beam dispersions to eliminate the influence of multiple second primary beam dispersions generated by the beam splitter on the multiple sub-beams. The first dispersion device includes a first electrostatic deflector and a first magnetic deflector that respectively apply a first force and a second force to each of the multiple sub-beams, the first force and the second force being opposite to each other and forming corresponding first primary beam dispersions.

[0013] Other objects and advantages of the disclosed embodiments will be set forth in part in the description which follows, and will be apparent in part from the description, or may be learned by practice of the embodiments. The objects and advantages of the disclosed embodiments may be realized and obtained by means of the elements and combinations set forth in the claims.

[0014] It should be understood that the foregoing general description and the following detailed description are exemplary and illustrative only, and are not limited to the claimed disclosed embodiments. Attached Figure Description

[0015] Figure 1 This is a schematic diagram illustrating an exemplary electron beam inspection (EBI) system consistent with embodiments of the present disclosure.

[0016] Figure 2A , Figure 2B The illustrations are consistent with the embodiments of this disclosure. Figure 1 A schematic diagram of an exemplary electron beam tool, which is part of an exemplary electron beam inspection system.

[0017] Figure 3A , Figure 3B , Figure 3C This is a schematic diagram illustrating an exemplary dispersive apparatus consistent with embodiments of the present disclosure.

[0018] Figure 4A , Figure 4B This is a schematic diagram illustrating an exemplary single-beam device consistent with embodiments of the present disclosure.

[0019] Figure 5 This is a schematic diagram illustrating an exemplary single-beam device consistent with embodiments of the present disclosure.

[0020] Figure 6 This is a schematic diagram illustrating an exemplary single-beam device consistent with embodiments of the present disclosure.

[0021] Figure 7 This is a schematic diagram illustrating an exemplary multi-beam device consistent with embodiments of the present disclosure.

[0022] Figure 8 This is a schematic diagram illustrating an exemplary multi-beam device consistent with embodiments of the present disclosure.

[0023] Figure 9 This is a schematic diagram illustrating an exemplary multi-beam device consistent with embodiments of the present disclosure.

[0024] Figure 10 This is a schematic diagram illustrating an exemplary single-beam device consistent with embodiments of the present disclosure.

[0025] Figure 11 This is a schematic diagram illustrating an exemplary multi-beam device consistent with embodiments of the present disclosure.

[0026] Figure 12 This is a schematic diagram illustrating an exemplary multi-beam device consistent with embodiments of the present disclosure.

[0027] Figure 13 This is a schematic diagram illustrating an exemplary multi-beam device consistent with embodiments of the present disclosure.

[0028] Figure 14 This is a schematic diagram illustrating an exemplary multi-beam device consistent with embodiments of the present disclosure.

[0029] Figure 15 This is a flowchart illustrating an exemplary method for controlling dispersion in a charged particle beam system, consistent with embodiments of this disclosure. Detailed Implementation

[0030] Exemplary embodiments, as illustrated in the accompanying drawings, will now be discussed in detail with reference to their examples. The following description refers to the accompanying drawings, in which, unless otherwise indicated, the same reference numerals in different drawings denote the same or similar elements. The implementations set forth in the following description of the exemplary embodiments do not represent all implementations consistent with the invention. Rather, they are merely examples of devices and methods consistent with aspects of the invention as set forth in the appended claims.

[0031] This disclosure relates to systems and methods for compensating for dispersion of a beam splitter in a single-beam or multi-beam device. The beam splitter generates dispersion over one or more primary beams and one or more secondary beams. Embodiments of this disclosure provide a dispersion device including an electrostatic deflector and a magnetic deflector configured to induce beam dispersion, the beam dispersion being set to eliminate dispersion generated by the beam splitter. A combination of the electrostatic and magnetic deflectors can be used to keep the deflection angle (due to the dispersion device) constant when the induced beam dispersion is altered to compensate for the dispersion variation generated by the beam splitter. In some embodiments, the deflection angle can be controlled to zero, and there is no change in the primary beam axis due to the dispersion device. In some embodiments, the dispersion device may include a multipole lens (e.g., a quadrupole lens) configured to generate a quadrupole field to eliminate at least one effect of astigmatism caused by the beam splitter and the dispersion device at the detection point formed by the primary beam.

[0032] Now for reference Figure 1 , Figure 1 An exemplary electron beam inspection (EBI) system 100 consistent with embodiments of this disclosure is illustrated. (As shown...) Figure 1 As shown, the EBI system 100 includes a main chamber 101, a loading / locking chamber 102, an electron beam tool 104, and an equipment front-end module (EFEM) 106. The electron beam tool 104 is located within the main chamber 101.

[0033] EFEM 106 includes a first loading port 106a and a second loading port 106b. EFEM 106 may include multiple additional loading ports. The first loading port 106a and the second loading port 106b can receive a front-opening wafer assembly (FOUP) containing wafers (e.g., semiconductor wafers or wafers made of multiple other materials) or samples to be inspected (wafers and samples are collectively referred to as “wafers” hereinafter). One or more robotic arms (not shown) in EFEM 106 can transfer the wafers to the loading / locking chamber 102.

[0034] Loading / locking chamber 102 is connected to a loading / locking vacuum pump system (not shown), which removes gas molecules from the loading / locking chamber 102 to achieve a first pressure below atmospheric pressure. After reaching the first pressure, one or more robotic arms (not shown) can transfer the wafer from the loading / locking chamber 102 to the main chamber 101. The main chamber 101 is connected to a main chamber vacuum pump system (not shown), which removes gas molecules from the main chamber 101 to achieve a second pressure below the first pressure. After reaching the second pressure, the wafer is inspected by an electron beam tool 104.

[0035] Now for reference Figure 2A , Figure 2A Exemplary components of an electron beam tool 104 consistent with embodiments of the present disclosure are illustrated. Figure 2A The diagram illustrates an electron beam tool 104A (also referred to herein as device 104A), which includes an electron source 206, a gun aperture 212, a focusing lens 214, a primary electron beam 210 emitted from the electron source 206, a beam confinement aperture 216, a beam splitter 222, a deflection scanning unit 226, an objective lens 228, and a sample stage. Figure 2A (Not shown in the image), secondary electron beam 220, and electron detector 218. Electron source 206, gun aperture 212, focusing lens 214, beam limiting aperture 216, beam splitter 222, deflection scanning unit 226, and objective lens 228 can be aligned with the optical axis 202 of device 104A.

[0036] Electron source 206 may include a cathode, extractor, or anode, wherein primary electrons may be emitted from the cathode and extracted or accelerated to form a primary electron beam 210 with high energy (e.g., 8-20 keV), high angular intensity (e.g., 0.1-1 mA / sr), and a cross (virtual or real) 208. The primary electron beam 210 can be considered as being emitted from the cross 208. A gun aperture 212 may block peripheral electrons of the primary electron beam 210 to reduce the Coulomb effect. The Coulomb effect can lead to an increase in the size of the probe point 236.

[0037] The focusing lens 214 focuses the primary electron beam 210, and the beam-limiting aperture 216 limits the size of the primary electron beam 210. The current of the primary electron beam 210 downstream of the beam-limiting aperture 216 can be changed by adjusting the focusing power of the focusing lens 214 or by changing the radial dimension of the beam-limiting aperture 216. The objective lens 228 focuses the primary electron beam 210 onto the sample 238 for inspection. The primary electron beam 210 can form a probe point 236 on the surface of the sample 238.

[0038] In response to the incident primary electron beam 210 at detector point 236, secondary electron beam 220 can be emitted from sample 238. Secondary electron beam 220 may include electrons with an energy distribution, including secondary electrons (energy ≤ 50 eV) and backscattered electrons (energy between 50 eV and the landing energy of primary electron beam 210).

[0039] Beam splitter 222 can be a Wien filter type beam splitter, which includes an electrostatic deflector that generates an electrostatic dipole field E1 and a magnetic dipole field B1. For a Wien filter type beam splitter, the force exerted on the electrons of the primary electron beam 210 by the electrostatic dipole field E1 is equal in magnitude and opposite in direction to the force exerted on the electrons by the magnetic dipole field B1. Therefore, the primary electron beam 210 can pass straight through beam splitter 222 with zero deflection angle. However, the total dispersion of the primary electron beam 210 generated by beam splitter 222 is not zero. For the dispersion plane 224 of beam splitter 222, Figure 2A A primary electron beam 210 with nominal energy V0 and energy spread ΔV is shown dispersed into a beam portion 230 corresponding to energy V0 - ΔV / 2, a beam portion 232 corresponding to energy V0, and a beam portion 234 corresponding to energy V0 + ΔV / 2. The total force exerted on the electrons of the secondary electron beam 220 by the beam splitter 222 is not zero. Therefore, the beam splitter 222 can separate the secondary electron beam 220 from the primary electron beam 210 and guide the secondary electron beam 220 toward the electron detector 218. The electron detector 218 can detect the secondary electron beam 220 and generate a corresponding signal.

[0040] The deflection scanning unit 226 can deflect the primary electron beam 210 to scan the detection point 236 on the surface region of the sample 238. The electron detector 218 can detect the corresponding secondary electron beam 220 and generate a corresponding signal for reconstructing an image of the surface region of the sample 238.

[0041] The object plane 204 of objective lens 228 can shift with changes in the focusing power of condenser lens 214. For primary electron beam 210, if the dispersive plane 224 of beam splitter 222 does not coincide with the object plane 204 of objective lens 228, beam portions 230, 232, and 234 remain separated, and probe point 236 extends in the dispersive direction. This may lead to a degradation in the resolution of the reconstructed image of sample 238.

[0042] Now for reference Figure 2B , Figure 2BThe diagram illustrates an electron beam tool 104B (also referred to herein as device 104B), which includes an electron source 206, a gun aperture 212, a focusing lens 214, a primary electron beam 210 emitted from the electron source 206, a source conversion unit 252, multiple sub-beams 254, 256, and 258 of the primary electron beam 210, a primary projection optics system 260, and a sample stage. Figure 2B (Not shown in the diagram) Multiple secondary electron beams 276, 278, and 280, a secondary optical system 282, and an electronic detection device 284. The primary projection optical system 260 may include an objective lens 228. The electronic detection device 284 may include detection elements 286, 288, and 290. A beam splitter 222 and a deflection scanning unit 226 may be placed inside the primary projection optical system 260.

[0043] The electronic source 206, the gun aperture 212, the focusing lens 214, the source conversion unit 252, the beam splitter 222, the deflection scanning unit 226, and the objective lens 228 can be aligned with the primary optical axis 250 of the device 104B. The secondary optical system 282 and the electronic detection device 284 can be aligned with the secondary optical axis 292 of the device 104B.

[0044] Electron source 206 may include a cathode, extractor, or anode, wherein primary electrons may be emitted from the cathode and extracted or accelerated to form a primary electron beam 210 having a cross (virtual or real) 208. The primary electron beam 210 can be considered to be emitted from the cross 208. A bore 212 may block peripheral electrons of the primary electron beam 210 to reduce the Coulomb effect. The Coulomb effect can lead to an increase in the size of the detection points 270, 272, and 274.

[0045] Source conversion unit 252 may include an array of image forming elements ( Figure 2B (not shown in the image) and arrays of beam-limiting apertures ( Figure 2B (Not shown in the image). The array of image forming elements may include an array of micro-deflectors or microlenses. The array of image forming elements can use multiple sub-beams 254, 256, and 258 of the primary electron beam 210 to form multiple parallel images (virtual or real) of the intersection 208. The array of beam-limiting apertures can limit multiple sub-beams 254, 256, and 258.

[0046] The focusing lens 214 can focus the primary electron beam 210. The current of the sub-beams 254, 256, and 258 downstream of the source conversion unit 252 can be changed by adjusting the focusing power of the focusing lens 214 or by changing the radial dimension of the corresponding beam-limiting aperture within the beam-limiting aperture array. The objective lens 228 can focus the sub-beams 254, 256, and 258 onto the sample 238 for inspection and can form multiple probe points 270, 272, and 274 on the surface of the sample 238.

[0047] Beam splitter 222 can be a Wien filter type beam splitter, which includes generating an electrostatic dipole field E1 and a magnetic dipole field B1 (neither of which is in the...). Figure 2B The electrostatic deflector (shown in the diagram) is used. If an electrostatic dipole field E1 and a magnetic dipole field B1 are applied, the force exerted by the electrostatic dipole field E1 on the electrons of sub-bundles 254, 256, and 258 is equal in magnitude and opposite in direction to the force exerted by the magnetic dipole field B1 on the electrons. Sub-bundles 254, 256, and 258 can therefore pass straight through beam splitter 222 with zero deflection angle. However, the total dispersion of sub-bundles 254, 256, and 258 generated by beam splitter 222 is non-zero. For the dispersion plane 224 of beam splitter 222, Figure 2B Sub-beam 254, with nominal energy V0 and energy spread ΔV, is shown dispersed into sub-beam portion 262 corresponding to energy V0, sub-beam portion 264 corresponding to energy V0 + ΔV / 2, and sub-beam portion 266 corresponding to energy V0 - ΔV / 2. The total force exerted on the electrons of secondary electron beams 276, 278, and 280 by beam splitter 222 is non-zero. Beam splitter 222 can therefore separate secondary electron beams 276, 278, and 280 from sub-beams 252, 254, and 256, and guide secondary electron beams 276, 278, and 280 toward secondary optical system 282.

[0048] The deflection scanning unit 226 can deflect sub-beams 254, 256, and 258 to scan detection points 270, 272, and 274 on the surface region of sample 238. In response to the incident of sub-beams 254, 256, and 258 at detection points 270, 272, and 274, secondary electron beams 276, 278, and 280 can be emitted from sample 238. The secondary electron beams 276, 278, and 280 can include electrons with an energy distribution comprising secondary electrons (energy ≤ 50 eV) and backscattered electrons (energy between 50 eV and the landing energy of sub-beams 254, 256, and 258). The secondary optical system 282 can focus the secondary electron beams 276, 278, and 280 onto detection elements 286, 288, and 290 of the electron detection device 284. Detection elements 286, 288, and 290 can detect the corresponding secondary electron beams 276, 278, and 280, and generate corresponding signals for reconstructing images of the surface region of sample 238.

[0049] Now for reference Figure 3A , Figure 3A This is a schematic diagram illustrating an exemplary dispersive apparatus consistent with embodiments of the present disclosure. Figure 3AThe diagram illustrates a dispersion device 310 including an electrostatic deflector and a magnetic deflector. The electrostatic deflector generates an electrostatic dipole field E2, and the magnetic deflector generates a magnetic dipole field B2, wherein E2 and B2 are superimposed in a manner substantially perpendicular to each other and perpendicular to the optical axis 330. The electrostatic dipole field E2 exerts a force F on the electrons of the electron beam 210 propagating along the optical axis 330. e Furthermore, the magnetic dipole field B2 applies a force F. m Force F e and F m Acting in essentially opposite directions. The total force exerted by the electrostatic dipole field E2 and the magnetic dipole field B2 on an electron with nominal energy V0 and nominal velocity v0 can be calculated using the following equation:

[0050] F(v0) = F e + F m = e (E2 - v0× B2) (1)

[0051] For an electron with energy V0+dV and velocity v0+dv, the total force exerted by the electrostatic dipole field E2 and the magnetic dipole field B2 can be calculated using the following equation:

[0052] F(v0 + dv) = F e + F m = F(v0) - (e × dv × B2) (2)

[0053] Now for reference Figure 3B , Figure 3B A dispersion device 311 consistent with an embodiment of this disclosure is illustrated. Similar to dispersion device 310, dispersion device 311 includes an electrostatic deflector and a magnetic deflector capable of generating corresponding electrostatic dipole fields E2 and B2. The electrostatic deflector and magnetic deflector can be arranged such that E2 and B2 are stacked substantially perpendicular to each other and perpendicular to the optical axis 331. In dispersion device 311, the electrostatic dipole field E2 and the magnetic dipole field B2 can be controlled such that the total force (F) e +F m The result can be essentially zero when E2 and B2 are changed. Therefore, as... Figure 3B As shown, the nominal deflection angle is zero. The deflection dispersion induced by the dispersion device 311 at the dispersion plane 341 can be controlled by changing E2 and B2 while keeping the deflection angle zero.

[0054] Now for reference Figure 3C , Figure 3CA dispersion device 312 consistent with embodiments of the present disclosure is illustrated. Similar to dispersion devices 310 and 311, dispersion device 312 includes an electrostatic deflector and a magnetic deflector capable of generating corresponding electrostatic dipole fields E2 and B2. The electrostatic deflector and magnetic deflector can be arranged such that E2 and B2 are stacked substantially perpendicular to each other and perpendicular to the optical axis 332. In dispersion device 312, the electrostatic dipole field E2 and the magnetic dipole field B2 can be controlled such that the total force (F) e +F m The constant non-zero value can be obtained when E2 and B2 are changed. Therefore, as... Figure 3C As shown, the nominal deflection angle α is non-zero. The deflection dispersion induced by the dispersion device 312 at the dispersion plane 342 can be controlled by changing E2 and B2 while keeping the deflection angle at α.

[0055] Now for reference Figure 4A , Figure 4A An exemplary single-beam device 400 consistent with embodiments of this disclosure is illustrated. The single-beam device 400 may further include... Figure 3B The dispersion device 311 Figure 2A Electron beam tool 104A. Figure 4A The diagram illustrates the operation of the dispersion device 311 when the object plane 204 of the objective lens 228 is above the objective lens 228. Figure 4B The diagram illustrates the operation of the dispersion device 311 when the object plane 204 of the objective lens 228 is below the objective lens 228. As described below, the disclosed embodiments can compensate for beam dispersion without limiting the operating modes of the objective lens 228.

[0056] The single-beam device 400 may include an electron source 206, a gun aperture 212, a focusing lens 214, a primary electron beam 210 emitted from the electron source 206, a beam-limiting aperture 216, a dispersion device 311, a beam splitter 222, a deflection scanning unit 226, an objective lens 228, a secondary electron beam 220, and an electron detector 218. The electron source 206, gun aperture 212, focusing lens 214, beam-limiting aperture 216, dispersion device 311, beam splitter 222, deflection scanning unit 226, and objective lens 228 may be aligned with the optical axis 402 of the single-beam device 400.

[0057] As referenced above Figure 3BThe nominal dispersion angle associated with the dispersion device 311 is zero, and the primary electron beam 210 can pass straight through the dispersion device 311. The dispersion device 311 can induce beam dispersion based on the values ​​of E2 and B2. The primary electron beam 210 can also pass straight through a Wien filter-type beam splitter 222. The beam splitter 222 can also induce beam dispersion based on the values ​​of E1 and B1. The beam dispersion induced by the beam splitter 222 can be referred to as the principal dispersion (MDS), and the beam dispersion induced by the dispersion device 311 can be referred to as the compensating dispersion (CDS). The dispersion device 311 can be configured and controlled to generate a CDS opposite to the direction of the MDS. For example, refer to... Figure 4A Electrons with energies greater than the nominal energy V0 can be deflected in the -x direction by beam splitter 222 and in the +x direction by dispersion device 311 (corresponding to beam path 430). Electrons with energies less than the nominal energy V0 can be deflected in the +x direction by beam splitter 222 and in the -x direction by dispersion device 311 (corresponding to beam path 434). The size of the CDS generated by dispersion device 311 can be controlled such that electrons with energies different from the nominal energy V0 (e.g., electrons corresponding to beam paths 430 and 434) are virtually focused on object plane 204. Therefore, objective lens 228 focuses primary electron beam 210 onto sample 238 to form detector point 236.

[0058] Now for reference Figure 5 , Figure 5 An exemplary single-beam device 500 consistent with embodiments of this disclosure is illustrated. The single-beam device 500 may include an electron source 206, a gun aperture 212, a focusing lens 214, a primary electron beam 210 emitted from the electron source 206, a beam-limiting aperture 216, a dispersion device 311, a beam splitter 510, a deflection scanning unit 226, an objective lens 228, a secondary electron beam 220, and an electron detector 218. The beam splitter 510 includes a magnetic deflector, and therefore the associated deflection angle 540 has a non-zero value. The electron source 206, gun aperture 212, focusing lens 214, beam-limiting aperture 216, dispersion device 311, beam splitter 510, deflection scanning unit 226, and objective lens 228 may be aligned relative to the optical axis 502 of the single-beam device 500.

[0059] As referenced above Figure 3BAs described, the nominal dispersion angle associated with the dispersion device 311 is zero, and the primary electron beam 210 can pass straight through the dispersion device 311 and has an associated beam dispersion CDS. Electrons of the primary electron beam 210 having a nominal energy V0 traveling along the optical axis 502 can be incident on the beam splitter 510 at an incident angle 540 (with respect to the optical axis of the beam splitter 510). Electrons having an energy > V0 traveling along the optical axis 502 can be incident on the beam splitter 510 at an incident angle < angle 540. Electrons having an energy < V0 traveling along the optical axis 502 can be incident on the beam splitter 510 at an incident angle > angle 540.

[0060] The beam splitter 510 can deflect the primary electron beam 210 with a nominal deflection angle equal to angle 540 and an associated beam dispersion MDS. Electrons having a nominal energy V0 can be deflected at an angle equal to angle 540. Electrons having an energy > V0 can be deflected at an angle less than angle 540. Electrons having an energy < V0 can be deflected at an angle greater than angle 540.

[0061] The CDS generated by the dispersion device 311 can be controlled such that the change in the incident angle generated by the CDS for electrons having different energies can compensate for the change in the deflection angle generated by the MDS. Thus, electrons having different energies can be controlled to be virtually focused on the object plane 204. In addition, the objective lens 228 can focus electrons having different energies (corresponding to the beam paths 530, 532, and 534) onto the sample 238 to form a detection point 236.

[0062] Now refer to Figure 6 , Figure 6 FIG. illustrates an exemplary single-beam device 600 consistent with an embodiment of the present disclosure. The single-beam device 600 can include an electron source 206, a gun aperture 212, a bunching lens 214, a primary electron beam 210 emitted from the electron source 206, a beam limiting aperture 216, a dispersion device 312, a beam splitter 510, a deflection scanning unit 226, an objective lens 228, a secondary electron beam 220, and an electron detector 218. The beam splitter 510 includes a magnetic deflector, and thus the associated deflection angle 642 has a non-zero value. The electron source 206, the gun aperture 212, the bunching lens 214, the beam limiting aperture 216, the dispersion device 312, the beam splitter 510, the deflection scanning unit 226, and the objective lens 228 can be aligned with respect to the optical axis 602 of the single-beam device 600.

[0063] As referred to above Figure 3CAs described, the nominal dispersion angle associated with the dispersion device 312 is non-zero, and the primary electron beam 210 can pass through the dispersion device 312 at the nominal deflection angle 641 and the associated beam dispersion CDS. For the single-beam device 600, electrons of the primary electron beam 210 having the nominal energy V0 traveling along the optical axis 602 can be deflected by the angle 641 at the deflection plane 342 (of the dispersion device 312), and can be incident on the deflection plane 520 (of the beam splitter 510) at the incident angle 641. Electrons having an energy > V0 traveling along the optical axis 602 can be incident on the beam splitter 510 at the incident angle < angle 641. Electrons having an energy < V0 traveling along the optical axis 602 can be incident on the beam splitter 510 at the incident angle > angle 641.

[0064] The beam splitter 510 can deflect the primary electron beam 210 at the nominal deflection angle 642 and the associated beam dispersion MDS. Electrons having the nominal energy V0 can be deflected by the angle 642 at the deflection plane 520. Electrons having an energy > V0 can be deflected at an angle less than the angle 642. Electrons having an energy < V0 can be deflected at an angle greater than the angle 642.

[0065] The CDS generated by the dispersion device 312 can be controlled such that the change in the incident angle generated by the CDS for electrons having different energies can compensate for the change in the deflection angle generated by the MDS. Thus, electrons having different energies can be controlled to be virtually focused on the object plane 204. In addition, the objective lens 228 can focus electrons having different energies (corresponding to the beam paths 630, 632, and 634) onto the sample 238 to form the detection point 236. The dispersion device 312 includes an electrostatic deflector and a magnetic deflector, and thus can change the CDS while maintaining the deflection angle 641 constant. Thus, the CDS can be changed to match the change in the position of the object plane 204, and there is no limitation on the operating mode of the objective lens 228. Another dispersion device 312 can be controlled to keep the angles 641 and 642 equal. Thus, the optical axis 602 can be kept parallel to the optical axis of the beam splitter 510. This can simplify the arrangement and alignment of the various components of the single-beam device 600.

[0066] Now refer to Figure 7 , Figure 7 FIG. illustrates an exemplary multi-beam device 700 consistent with an embodiment of the present disclosure. The multi-beam device 700 can be an electron beam tool 104A of Figure 3B further including Figure 2B the dispersion device 311.

[0067] The multi-beam device 700 may include an electron source 206, a gun aperture 212, a focusing lens 214, a primary electron beam 210 emitted from the electron source 206, a source conversion unit 252, multiple sub-beams 254, 256, and 258 of the primary electron beam 210, a primary projection optics system 260, multiple secondary electron beams 730, 732, and 734, a secondary optics system 282, and an electronic detection device 284. The primary projection optics system 260 may include an objective lens 228. The electronic detection device 284 may include detection elements 286, 288, and 290. A dispersion device 311, a beam splitter 222, and a deflection scanning unit 226 may be housed within the primary projection optics system 260.

[0068] The electronic source 206, the aperture 212, the focusing lens 214, the source conversion unit 252, the dispersion device 311, the beam splitter 222, the deflection scanning unit 226, and the objective lens 228 can be aligned with the primary optical axis 702 of the device 700. The secondary optical system 282 and the electronic detection device 284 can be aligned with the secondary optical axis 292 of the device 700.

[0069] As referenced above Figure 3B The nominal dispersion angle associated with the dispersion device 311 is zero, and sub-beams 254, 256, and 258 can pass straight through the dispersion device 311. The dispersion device 311 can induce CDS for sub-beams 254, 256, and 258. The dispersion device 311 can be positioned above the primary projection optics system 260.

[0070] Sub-beams 254, 256, and 258 can also pass straight through a Wien filter-type beam splitter 222. Beam splitter 222 can be used to induce MDS for the sub-beams. (See above reference.) Figure 4A and Figure 4B The dispersion device 311 can be configured and controlled to generate a CDS opposite to the direction of the MDS. The size of the CDS generated by the dispersion device 311 can be controlled such that the dispersive electrons of each sub-beam (e.g., electrons corresponding to beam paths 720 and 724) are virtually focused on the object plane of the objective lens 228. Thus, the objective lens 228 focuses the dispersive electrons of sub-beams 254, 256, and 258 onto the sample 238 to form corresponding detection points 270, 272, and 274.

[0071] Now for reference Figure 8 , Figure 8FIG. illustrates an exemplary multi-beam device 800 consistent with embodiments of the present disclosure. The multi-beam device 800 may include an electron source 206, a gun aperture 212, a bunching lens 214, a primary electron beam 210 emitted from the electron source 206, a source conversion unit 252, multiple sub-beams 254, 256, and 258 of the primary electron beam 210, a primary projection optical system 260, multiple secondary electron beams 830, 832, and 834, a secondary optical system 282, and an electron detection device 284. The primary projection optical system 260 may include an objective lens 228. The electron detection device 284 may include detection elements 286, 288, and 290. A dispersion device 311, a beam splitter 510, and a deflection scanning unit 226 may be disposed inside the primary projection optical system 260.

[0072] The electron source 206, the gun aperture 212, the bunching lens 214, the source conversion unit 252, the dispersion device 311, the beam splitter 510, the deflection scanning unit 226, and the objective lens 228 may be aligned with the primary optical axis 802 of the device 800. The secondary optical system 282 and the electron detection device 284 may be aligned with the secondary optical axis 292 of the device 800.

[0073] As referred to above as Figure 3B 所述,与分散装置311相关联的标称色散角为零,并且子束254、256和258可以笔直穿过分散装置311。分散装置311可以针对子束254、256和258诱导CDS。分散装置311可以被放置在初级投影光学系统260上方。

[0074] The beam splitter 510 may deflect the sub-beams 254, 256, and 258 with a nominal deflection angle equal to the angle 804 and an associated beam dispersion MDS. Electrons having a nominal energy V0 may be deflected at an angle equal to the angle 804. Electrons having an energy > V0 may be deflected at an angle less than the angle 804. Electrons having an energy < V0 may be deflected at an angle greater than the angle 804.

[0075] The CDS generated by the dispersion device 311 may be controlled such that the change in the incident angle generated by the CDS for electrons having different energies may compensate for the change in the deflection angle generated by the MDS. Thus, electrons having different energies may be controlled to be virtually focused on the object plane of the objective lens 228. In addition, the objective lens 228 may focus electrons having different energies (corresponding to the beam paths 820, 822, and 824) onto the sample 238 to form corresponding detection points 270, 272, and 274.

[0076] Now refer to Figure 9 , Figure 9FIG. illustrates an exemplary multi-beam device 900 consistent with embodiments of the present disclosure. The multi-beam device 900 may include an electron source 206, a gun aperture 212, a bunching lens 214, a primary electron beam 210 emitted from the electron source 206, a source conversion unit 252, multiple sub-beams 254, 256, and 258 of the primary electron beam 210, a primary projection optical system 260, multiple secondary electron beams 930, 932, and 934, a secondary optical system 282, and an electron detection device 284. The primary projection optical system 260 may include an objective lens 228. The electron detection device 284 may include detection elements 286, 288, and 290. A dispersion device 312, a beam splitter 510, and a deflection scanning unit 226 may be placed inside the primary projection optical system 260.

[0077] The electron source 206, the gun aperture 212, the bunching lens 214, the source conversion unit 252, the dispersion device 312, the beam splitter 510, the deflection scanning unit 226, and the objective lens 228 may be aligned with the primary optical axis 902 of the device 900. The secondary optical system 282 and the electron detection device 284 may be aligned with the secondary optical axis 292 of the device 900.

[0078] As referred to above Figure 3C The nominal dispersion angle associated with the dispersion device 312 is non-zero, and the primary electron beam 210 may pass through the dispersion device 312 with a nominal deflection angle 908 and an associated beam dispersion CDS. Electrons of the sub-beams 254, 256, and 258 having a nominal energy V0 traveling along the optical axis 902 may be incident on the beam splitter 510 at an incident angle 908. Electrons having an energy > V0 traveling along the optical axis 902 may be incident on the beam splitter 510 at an incident angle < angle 908. Electrons having an energy < V0 traveling along the optical axis 902 may be incident on the beam splitter 510 at an incident angle > angle 908. The dispersion device 312 may be placed above the primary projection optical system 260.

[0079] The beam splitter 510 may deflect the sub-beams 254, 256, and 258 with a nominal deflection angle equal to angle 910 and an associated beam dispersion MDS. Electrons having a nominal energy V0 may be deflected at an angle equal to angle 910. Electrons having an energy > V0 may be deflected at an angle less than angle 910. Electrons having an energy < V0 may be deflected at an angle greater than angle 910.

[0080] The CDS generated by the dispersion device 312 can be controlled such that changes in the incident angle generated by the CDS for electrons with different energies can compensate for changes in the deflection angle generated by the MDS. Therefore, electrons with different energies can be controlled to be virtually focused on the object plane of the objective lens 228. Furthermore, the objective lens 228 can focus electrons with different energies (corresponding to beam paths 920, 922, and 924) onto the sample 238 to form corresponding detection points 270, 272, and 274. The dispersion device 312 includes an electrostatic deflector and a magnetic deflector, and the CDS can therefore be varied while maintaining a constant deflection angle 908. Therefore, the CDS can be changed to match changes in the position of the object plane 204, and there are no limitations on the operating mode of the objective lens 228. Furthermore, the dispersion device 312 can be controlled to keep angles 908 and 910 equal. Therefore, the optical axis 902 can be kept parallel to the optical axis 906 of the beam splitter 510. This simplifies the arrangement and alignment of the various components of the single-beam device 900.

[0081] Now for reference Figure 10 , Figure 10 An exemplary single-beam device 1000 consistent with embodiments of the present disclosure is illustrated. The single-beam device 1000 may include an electron source 206, a gun aperture 212, a focusing lens 214, a beam-limiting aperture 216, a multipole lens 1010, a dispersion device 311, a beam splitter 222, a deflection scanning unit 226, an objective lens 228, and an electron detector 218. The electron source 206, gun aperture 212, focusing lens 214, beam-limiting aperture 216, multipole lens 1010, dispersion device 311, beam splitter 222, deflection scanning unit 226, and objective lens 228 may be aligned with the optical axis 1002 of the single-beam device 1000. The multipole lens 1010 may be configured to generate a quadrupole field to eliminate the effect of one or both of the astigmatic aberrations caused by the beam splitter 222 and dispersion device 311 on the primary beam detection point. The multipole lens 1010 can be placed at different locations between the electron source 206 and the sample 238. In some embodiments, the multipole lens 1010 can be placed adjacent to the beam splitter 222. In some embodiments, the multipole lens 1010 can be placed adjacent to the dispersion device 311.

[0082] In some embodiments, one or both of the electrostatic deflector and magnetic deflector of the dispersion device may include a multipole structure configured to generate a quadrupole field to eliminate the effects of astigmatism. For example... Figure 3B , Figure 4A to Figure 4B , Figure 5 , Figure 7 , Figure 8 or Figure 10 The dispersion device 311 may include a quadrupole field. In other examples, Figure 6 or Figure 9The dispersion device 312 may include a quadrupole field.

[0083] In some embodiments, one or both of the electrostatic deflectors and magnetic deflectors of the beam splitter may include a multipole structure configured to generate a quadrupole field to eliminate the effects of astigmatism. For example... Figure 4A , Figure 4B , Figure 7 or Figure 10 The beam splitter 222 may include a quadrupole field. In other examples, Figure 5 , Figure 6 , Figure 8 or Figure 9 The beam splitter 510 may include a quadrupole field.

[0084] In some embodiments, one of the image forming elements within the source conversion unit may include a multipole structure configured to generate a quadrupole field to eliminate the effects of astigmatism. For example... Figure 7 , Figure 8 or Figure 9 The image forming element within the source conversion unit 252 may include a quadrupole field.

[0085] In some embodiments, the source conversion unit may include an array of image compensation elements. One of the image compensation elements may include a multipole structure configured to generate a quadrupole field to eliminate the effects of astigmatic aberration. For example, Figure 7 , Figure 8 or Figure 9 The image compensation element within the source conversion unit 252 may include a quadrupole field.

[0086] Now for reference Figure 11 , Figure 11 An exemplary multi-beam device 1100 consistent with embodiments of this disclosure is illustrated. The multi-beam device 1100 may further include a first-stage deflector 1110 and a second-stage deflector 1120. Figure 8 The multi-beam device 800. In some embodiments, the secondary deflector 1110 may be an electrostatic deflector. In other embodiments, the secondary deflector 1110 may be a magnetic deflector. In some embodiments, the secondary deflector 1120 may be an electrostatic deflector. In other embodiments, the secondary deflector 1120 may be a magnetic deflector.

[0087] The multi-beam device 1100 may include an electronic source 206, a gun aperture 212, a focusing lens 214, a source conversion unit 252, a primary projection optics system 260, secondary deflectors 1110 and 1120, a secondary optics system 282, and an electronic detection device 284. The primary projection optics system 260 may include an objective lens 228. The electronic detection device 284 may include detection elements 286, 288, and 290. A beam splitter 311, a beam splitter 510, and a deflection scanning unit 226 may be housed within the primary projection optics system 260.

[0088] An electron source 206, a gun aperture 212, a focusing lens 214, a source conversion unit 252, a dispersion device 311, a beam splitter 510, a deflection scanning unit 226, and an objective lens 228 can be aligned with the primary optical axis 1102 of the device 1100. A secondary optical system 282 and an electronic detection device 284 can be aligned with the secondary optical axis 292 of the device 1100. Secondary deflectors 1110 and 1120 can be arranged between the beam splitter 510 and the electronic detection device 284. In some embodiments, secondary deflectors 1110 and 1120 can be configured to adjust at least one of the position and angle at which the secondary charged particle beam 1130 is incident on the detector.

[0089] Now for reference Figure 12 , Figure 12 An exemplary multi-beam device 1200 consistent with embodiments of this disclosure is illustrated. The multi-beam device 1200 may further include a dispersing device 1210. Figure 7 The multi-beam device 700.

[0090] The multi-beam device 1200 may include an electron source 206, a gun aperture 212, a focusing lens 214, a primary electron beam 210 emitted from the electron source 206, a source conversion unit 252, multiple sub-beams 254, 256, and 258 of the primary electron beam 210, a primary projection optics system 260, multiple secondary electron beams 730, 732, and 734, a secondary optics system 282, and an electronic detection device 284. The primary projection optics system 260 may include an objective lens 228. A dispersion device 311, a beam splitter 222, and a deflection scanning unit 226 may be disposed within the primary projection optics system 260. The electronic detection device 284 may include detection elements 286, 288, and 290. In some embodiments, the dispersion device 1210 may be disposed between the beam splitter 222 and the secondary optics system 282. In other embodiments, the dispersion device 1210 may be disposed between the electronic detection device 284 and the secondary optics system 282. The dispersion device 1210 may be similar to Figure 3B Dispersion device 311.

[0091] The electron source 206, the gun aperture 212, the beam focusing lens 214, the source conversion unit 252, the dispersion device 311, the beam splitter 222, the deflection scanning unit 226, and the objective lens 228 can be aligned with the primary optical axis 702 of the device 1200. The secondary optical system 282 and the electron detection device 284 can be aligned with the secondary optical axis 292 of the device 700.

[0092] The nominal deflection angles of the secondary beams 730, 732, and 734 associated with the beam splitter 222 are non-zero, and the secondary beams can pass through the beam splitter 222 with the nominal deflection angle 1220 and the associated beam dispersion MDS_2. The electrons of the secondary electron beams 730, 732, or 734 traveling along the optical axis 702 can enter the secondary optical system 282 at an incident angle of zero. The electrons traveling along the optical axis 702 with an energy > V s can enter the secondary optical system 282 at an incident angle < zero (clockwise with respect to the axis 292). The electrons traveling along the optical axis 702 with an energy > V s can enter the secondary optical system 282 at an incident angle < zero (clockwise with respect to the axis 292). The electrons traveling along the optical axis 702 with an energy < V s can enter the secondary optical system 282 at an incident angle > zero (counterclockwise with respect to the axis 292).

[0093] The dispersion device 1210 can deflect the secondary electron beams 730, 732, and 734 with a nominal deflection angle equal to 0 and the associated beam dispersion CDS_2. The electrons with the nominal energy V S are not deflected by the dispersion device 1210. The electrons with an energy > V S can be deflected clockwise, while the electrons with an energy < V0 can be deflected counterclockwise.

[0094] The CDS_2 generated by the dispersion device 1210 can be controlled to compensate for the deflection angle variation associated with MDS_2. Therefore, electrons with different energies can be controlled to virtually focus on the object plane of the downstream lens of the secondary optical system 282, and corresponding beam spots can be formed at the detection elements 286, 288, and 290.

[0095] Now refer to Figure 13 , Figure 13An exemplary multi-beam device 1300 consistent with embodiments of the present disclosure is illustrated. The multi-beam device 1300 may include an electron source 206, a gun aperture 212, a focusing lens 214, a primary electron beam 210 emitted from the electron source 206, a source conversion unit 252, a plurality of sub-beams 254, 256, and 258 of the primary electron beam 210, a primary projection optics system 260, a plurality of secondary electron beams 1321, 1322, and 1323, a dispersion device 1330, a secondary optical system 282, and an electronic detection device 284. The primary projection optics system 260 may include an objective lens 228. The dispersion device 311, beam splitter 222, and deflection scanning unit 226 may be disposed within the primary projection optics system 260. The electronic detection device 284 may include detection elements 286, 288, and 290. In some embodiments, the dispersion device 1330 may be disposed between the beam splitter 222 and the secondary optical system 282 (e.g., ...). Figure 13 (As shown). In other embodiments, the dispersion device 1330 may be placed inside the secondary system 282. In other embodiments, the dispersion device 1330 may be placed between the electronic detection device 284 and the secondary optical system 282. The dispersion device 1330 may be similar to... Figure 3C The dispersion device 312.

[0096] The electronic source 206, the aperture 212, the focusing lens 214, the source conversion unit 252, the dispersion device 311, the beam splitter 222, the deflection scanning unit 226, and the objective lens 228 can be aligned with the primary optical axis 1302 of the device 1300. The secondary optical system 282 and the electronic detection device 284 can be aligned with the secondary optical axis 1340 of the device 1300.

[0097] The secondary beams 1321, 1322, and 1323 associated with beam splitter 222 have a nominal deflection angle of 1305°, and the secondary beams can pass through beam splitter 222 with a nominal deflection angle of 1305° and an associated beam dispersion MDS_2. A beam with a nominal energy V travels along the optical axis 1302. s Electrons from the secondary electron beams 1321, 1322, and 1323 can be incident at the dispersion device 1330 at a zero incident angle. Electrons traveling along the optical axis 1302 have energies >V. s Electrons can be incident at the dispersion device 1330 with an incident angle < zero (clockwise relative to axis 1340). Electrons traveling along the optical axis 1302 possess energy... <V s Electrons can be incident at the dispersion device 1330 at an incident angle > zero (counterclockwise relative to axis 1340).

[0098] The dispersion device 1330 can deflect the secondary electron beams 1321, 1322, and 1323 with a nominal non-zero deflection angle 1310 and the associated beam dispersion CDS_2. It has a nominal energy V.S The electrons having are deflected by the electron dispersing device 1330 at an angle 1310. Having an energy > V S The electrons having can be deflected at an angle less than 1310, while the electrons having an energy < V0 can be deflected at an angle greater than 1310.

[0099] The CDS_2 generated by the dispersing device 1330 can be controlled to compensate for the change in the deflection angle associated with MDS_2. The CDS_2 can be controlled such that electrons having different energies are deflected at very similar angles after leaving the dispersing device 1330 and focused on the object plane of the first lens within the secondary optical system 282. Thus, electrons having different energies can be controlled to converge and form beam spots at the detection elements 286, 288, and 290.

[0100] Now refer to Figure 14 , Figure 14 FIG. illustrates an exemplary multi-beam device 1400 consistent with an embodiment of the present disclosure. The multi-beam device 1400 can be a multi-beam device 1100 that further includes a multipole lens 1010 and a dispersing device 1210 Figure 11 .

[0101] The multi-beam device 1400 can include an electron source 206, a gun aperture 212, a bunching lens 214, a source conversion unit 252, a multipole lens 1010, a primary projection optical system 260, a secondary deflector 1110, a secondary deflector 1120, a secondary optical system 282, and an electron detection device 284. The primary projection optical system 260 can include an objective lens 228. The electron detection device 284 can include detection elements 286, 288, and 290.

[0102] The electron source 206, the gun aperture 212, the bunching lens 214, the source conversion unit 252, the multipole lens 1010, the dispersing device 311, the beam splitter 510, the deflection scanning unit 226, and the objective lens 228 can be aligned with the primary optical axis 1102 of the device 1400. The secondary optical system 282 and the electron detection device 284 can be aligned with the secondary optical axis 292 of the device 1100. The secondary deflector 1110 and the secondary deflector 1120 can be arranged between the beam splitter 510 and the electron detection device 284.

[0103] The dispersing device 311 can be configured to compensate for the dispersion of the sub-beams of the primary electron beam caused by the beam splitter 510. The quadrupole field of the multipole lens 1010 can be configured to compensate for the astigmatism aberration of the sub-beams introduced by the dispersing device 311 and the beam splitter 510. The secondary deflector 1110 and the secondary deflector 1120 can be configured to adjust at least one of the position and the angle of the secondary charged particle beam 1130. The dispersing device 1210 can be configured to compensate for the dispersion of the secondary electron beam caused by the beam splitter 510.

[0104] Figure 15 This is a flowchart illustrating an exemplary method 1500 for controlling dispersion in a charged particle beam system with a beam splitter, consistent with embodiments of this disclosure. For example, method 1500 may be... Figure 14 The process can be performed using a multi-beam device 1400 or any other disclosed beam device. It is readily understood that the illustrated process can be altered to modify the order of steps, remove steps, or further include additional steps.

[0105] Following the initial startup, in step 1510, a dispersion device (e.g., dispersion device 311 of the multi-beam device 1400) induces dispersion in the primary beam of the charged particle beam system. The induced dispersion may be substantially opposite to the dispersion of the primary beam caused by the beam splitter.

[0106] In step 1520, the multipole lens (e.g., the multipole lens 1010 of the multi-beam device 1400) can generate a quadrupole field to compensate for astigmatism introduced by the dispersion device and the beam splitter. In some embodiments, the multipole lens may be included within the dispersion device or the beam splitter.

[0107] In step 1530, one or more secondary deflectors (e.g., secondary deflectors 1110 and 1120) can adjust the position or angle of the secondary electron beam incident on the detector. In some embodiments, the secondary deflector may be an electrostatic deflector. In other embodiments, the secondary deflector may be a magnetic deflector.

[0108] In step 1540, the dispersion device (e.g., dispersion device 1210 of the multi-beam device 1400) induces dispersion in the secondary beam of the charged particle beam system. The induced dispersion may be substantially opposite to the dispersion of the secondary beam caused by the beam splitter.

[0109] The embodiments may be further described using the following terms:

[0110] 1. A dispersion device for a charged particle beam system having a beam splitter, the dispersion device comprising:

[0111] Electrostatic deflectors and magnetic deflectors are configured to induce a first beam dispersion in the system's charged particle beam, wherein the first beam dispersion is set to eliminate the effect of a second beam dispersion caused by the beam splitter.

[0112] An electrostatic deflector applies a first force to the beam, and a magnetic deflector applies a second force to the beam. The first and second forces are substantially opposite to each other and form a first beam dispersion.

[0113] 2. The dispersion device according to Clause 1, wherein when the dispersion of the first beam is changed relative to the dispersion of the second beam, the deflection angle of the beam caused by the dispersion device remains unchanged.

[0114] 3. The dispersing device according to Clause 2, wherein the deflection angle is zero.

[0115] 4. The dispersion device according to Clause 1 further includes a multipole lens that can generate a quadrupole field to eliminate the effects of astigmatism caused by the first force and the second force.

[0116] 5. A dispersing device according to Clause 1, wherein the beam of charged particles is an electron beam.

[0117] 6. A dispersion device according to any one of clauses 1 to 5, wherein the charged particle beam system includes an electron beam inspection tool.

[0118] 7. A charged particle beam device, comprising:

[0119] Source, used to generate primary charged particle beams;

[0120] The first dispersing device is located below the source;

[0121] The beam splitter is located below the first dispersing device;

[0122] The objective lens is located below the beam splitter;

[0123] The sample stage is used to support the sample; and

[0124] The detector is located above the beam splitter.

[0125] The primary charged particle beam is focused onto the sample through the objective lens, forming a primary detection point on it, and from this, a secondary charged particle beam is generated.

[0126] The beam splitter separates the primary charged particle beam from the secondary charged particle beam, allowing the secondary charged particle beam to be detected by the detector.

[0127] The first dispersion device generates a first primary beam dispersion for the primary charged particle beam, and the beam splitter generates a second primary beam dispersion for the primary charged particle beam and a second secondary beam dispersion for the secondary charged particle beam.

[0128] The first dispersion device includes a first electrostatic deflector and a first magnetic deflector that apply a first force and a second force to the primary charged particle beam, respectively, and the first force and the second force are opposite to each other and form a first primary beam dispersion.

[0129] The first primary beam dispersion is adjusted to eliminate the influence of the second primary beam dispersion on the primary detection point.

[0130] 8. A charged particle beam device according to Clause 7, wherein the beam splitter includes a second magnetic deflector.

[0131] 9. A charged particle beam apparatus according to Clause 8, wherein a first deflection angle of the primary charged particle beam caused by a first dispersing device is equal to and opposite to a second deflection angle of the primary charged particle beam caused by a beam splitter.

[0132] 10. A charged particle beam apparatus according to Clause 8, wherein the first deflection angle of the primary charged particle beam caused by the first dispersing device is zero.

[0133] 11. Charged particle beam apparatus according to Clause 7, wherein the beam splitter includes a Wien filter.

[0134] 12. A charged particle beam apparatus according to Clause 11, wherein the first deflection angle of the primary charged particle beam caused by the first dispersing device is zero.

[0135] 13. The charged particle beam device according to Clause 7 further includes one or more secondary deflectors located between the beam splitter and the detector, and configured to adjust at least one of the position and angle of the secondary charged particle beam incident on the detector.

[0136] 14. The charged particle beam apparatus according to Clause 7 further includes a first multipole lens configured to generate a quadrupole field to eliminate at least one of the astigmatic aberrations caused by the beam splitter and the first dispersion device to the primary detection point.

[0137] 15. A charged particle beam apparatus according to Clause 14, wherein a first multipole lens is positioned adjacent to one of a beam splitter and a first dispersion device.

[0138] 16. A charged particle beam apparatus according to any one of Clauses 7 and 14, wherein the beam splitter includes a second multipole lens configured to generate a quadrupole field to eliminate at least one of the astigmatic aberrations caused by the beam splitter and the first dispersion device to the primary detection point.

[0139] 17. A charged particle beam system according to any one of clauses 7, 14 and 16, wherein the first dispersion device includes a third multipole lens configured to generate a quadrupole field to eliminate at least one of the astigmatic aberrations caused by the beam splitter and the first dispersion device to the primary detection point.

[0140] 18. A charged particle beam system according to any one of clauses 7 and 13, further comprising a second dispersion device located between the beam splitter and the detector, and generating a first-order beam dispersion of the secondary charged particle beam, the second dispersion device comprising:

[0141] The third electrostatic deflector and the third magnetic deflector, wherein their deflection fields are adjusted such that the first-stage beam dispersion eliminates the effect of the second-stage beam dispersion on the secondary detection point of the secondary charged particle beam on the detector.

[0142] 19. A charged particle beam system according to Clause 7, wherein the charged particle beam is an electron beam.

[0143] 20. A method for controlling dispersion in a charged particle beam system with a beam splitter, comprising:

[0144] A first dispersion device is provided in the path of the primary charged particle beam of the system;

[0145] The first dispersing device is placed upstream of the beam splitter;

[0146] A first primary beam dispersion of the primary charged particle beam is generated by a first dispersion device; and

[0147] The first primary beam dispersion is adjusted to eliminate the influence of the second primary beam dispersion of the primary charged particle beam caused by the beam splitter.

[0148] The first dispersion device includes a first electrostatic deflector and a first magnetic deflector that apply a first force and a second force to the primary charged particle beam, respectively, and the first force and the second force are opposite to each other and form a first primary beam dispersion.

[0149] 21. The method according to Clause 20 further includes:

[0150] One or more secondary deflectors are provided between the beam splitter and the detector, arranged along the path of the secondary charged particle beam, wherein the secondary charged particle beam is generated from the sample by the primary charged particle beam.

[0151] 22. The method according to Clause 21 further includes:

[0152] Operate one or more secondary deflectors to adjust at least one of the position and angle of the secondary charged particle beam incident on the detector.

[0153] 23. The method according to Clause 20 further includes:

[0154] A multipole lens is provided, which generates a quadrupole field to eliminate at least one of the astigmatic aberrations caused by the beam splitter and the first dispersion device.

[0155] 24. The method according to Clause 20 further includes:

[0156] A second dispersion device is provided, which generates a first-order beam dispersion of a secondary charged particle beam of the system, wherein the secondary charged particle beam is generated from a primary charged particle beam from a sample. The second dispersion device includes a second electrostatic deflector and a second magnetic deflector that apply a third force and a fourth force to the secondary charged particle beam, respectively, and the third force and the fourth force are opposite to each other and form the first-order beam dispersion.

[0157] 25. The method according to Clause 24 further includes:

[0158] The first-stage beam dispersion is adjusted to eliminate the effect of the second-stage beam dispersion of the secondary charged particle beam caused by the beam splitter.

[0159] 26. A charged particle beam device, comprising:

[0160] The source is configured to provide a primary beam of charged particles;

[0161] The source conversion unit is configured to use multiple sub-beams of the primary charged particle beam to form multiple parallel images of the source;

[0162] The first projection system has an objective lens and is configured to project multiple parallel images onto the sample, and thus utilizes multiple sub-beams to form multiple primary detection points thereon.

[0163] The beam splitter is configured to separate multiple sub-beams and multiple secondary charged particle beams generated from the sample through multiple primary probe points.

[0164] The detection device has multiple detection elements;

[0165] The secondary projection system is configured to focus multiple secondary charged particle beams onto a detection device, forming multiple secondary detection points thereon, and these secondary detection points are detected by multiple detection elements; and

[0166] A first dispersion device, disposed upstream of the beam splitter, is configured to generate multiple first primary beam dispersions for multiple sub-beams, wherein the multiple first primary beam dispersions are adjusted to eliminate the influence of multiple second primary beam dispersions generated by the beam splitter on multiple primary detection points.

[0167] The first dispersion device includes a first electrostatic deflector and a first magnetic deflector that apply a first force and a second force to each of the plurality of sub-beams, respectively, the first force and the second force being opposite to each other and forming a corresponding first primary beam dispersion.

[0168] 27. A charged particle beam device according to Clause 26, wherein the beam splitter includes a second magnetic deflector.

[0169] 28. A charged particle beam device according to Clause 27, wherein the first deflection angle of one of a plurality of sub-beams caused by a first dispersing device is zero.

[0170] 29. A charged particle beam device according to Clause 27, wherein a first deflection angle of one of a plurality of sub-beams caused by a first dispersing device is equal to and opposite to a second deflection angle of one of a plurality of sub-beams caused by a beam splitter.

[0171] 30. Charged particle beam apparatus according to Clause 26, wherein the beam splitter includes a Wien filter.

[0172] 31. A charged particle beam device according to Clause 30, wherein the first deflection angle of one of a plurality of sub-beams caused by the first dispersing device is zero.

[0173] 32. The charged particle beam apparatus according to Clause 26 further includes one or more secondary deflectors located between the beam splitter and the secondary projection system, and configured to adjust at least one of the positions and angles of each of the plurality of secondary charged particle beams incident on the secondary projection system.

[0174] 33. The charged particle beam apparatus according to Clause 26 further includes a first multipole lens configured to generate a quadrupole field to eliminate the effects of astigmatism caused by at least one of the beam splitter and the first dispersion device on a plurality of primary detection points.

[0175] 34. A charged particle beam apparatus according to Clause 33, wherein a first multipole lens is placed adjacent to one of a beam splitter and a first dispersion device.

[0176] 35. A charged particle beam apparatus according to any one of clauses 26 and 33, wherein the beam splitter includes a second multipole lens configured to generate a quadrupole field to eliminate the effects of astigmatism caused by at least one of the beam splitter and the first dispersion device on a plurality of primary detection points.

[0177] 36. A charged particle beam system according to any one of clauses 26, 33 and 35, wherein the first dispersion device includes a third multipole lens configured to generate a quadrupole field to eliminate the effects of astigmatism caused by at least one of the beam splitter and the first dispersion device on a plurality of primary detection points.

[0178] 37. A charged particle beam system according to any one of clauses 26, 33, 35 and 36, wherein the source conversion unit comprises a plurality of sixth multipole lenses, each of the plurality of sixth multipole lenses being configured to generate a quadrupole field to eliminate the effect of astigmatism caused by at least one of the beam splitter and the first dispersion device on the corresponding primary detection point.

[0179] 38. The charged particle beam apparatus according to Clause 26 further includes a fourth multipole lens configured to generate a quadrupole field to eliminate the effects of astigmatism caused by the beam splitter on multiple secondary detection points.

[0180] 39. The charged particle beam system according to Clause 26, further comprising a second dispersion device, the second dispersion device being located between the beam splitter and the detection device and generating a plurality of first-stage beam dispersions for a plurality of secondary charged particle beams, the second dispersion device comprising:

[0181] The third electrostatic deflector and the third magnetic deflector apply a third force and a fourth force, respectively, to each of the multiple secondary charged particle beams. The third force and the fourth force are opposite to each other and form the corresponding first-stage beam dispersion.

[0182] Multiple primary beam dispersions are adjusted to eliminate the influence of multiple secondary beam dispersions generated by the beam splitter on multiple secondary detection points.

[0183] 40. The charged particle beam apparatus according to Clause 39 further includes a fourth multipole lens configured to generate a quadrupole field to eliminate the effects of astigmatism caused by at least one of the beam splitter and the second dispersion device on a plurality of secondary detection points.

[0184] 41. A charged particle beam apparatus according to any one of clauses 39 and 40, wherein the second dispersion device includes a fifth multipole lens configured to generate a quadrupole field to eliminate the effects of astigmatism caused by at least one of the beam splitter and the second dispersion device on a plurality of secondary detection points.

[0185] 42. A charged particle beam system according to Clause 26, wherein the primary charged particle beam is an electron beam.

[0186] 43. A method for controlling dispersion in a charged particle beam system with a beam splitter, comprising:

[0187] A source conversion unit is provided to form multiple images of the source by multiple sub-beams of a primary charged particle beam generated by the source;

[0188] A first dispersing device is provided in the path of multiple sub-bundles;

[0189] The first dispersing device is placed upstream of the beam splitter;

[0190] The first dispersive device generates multiple first primary beam dispersions from multiple sub-beams; and

[0191] Multiple first primary beam dispersions are adjusted to eliminate the influence of multiple second primary beam dispersions generated by the beam splitter on multiple sub-beams.

[0192] The first dispersion device includes a first electrostatic deflector and a first magnetic deflector that apply a first force and a second force to each of the plurality of sub-beams, respectively, the first force and the second force being opposite to each other and forming a corresponding first primary beam dispersion.

[0193] 44. The method according to Clause 43 further includes:

[0194] A second dispersion device is provided, which generates multiple first-order beam dispersions of multiple secondary charged particle beams of the system, wherein the multiple secondary charged particle beams are generated from a sample by multiple sub-beams. The second dispersion device includes a second electrostatic deflector and a second magnetic deflector that apply a third force and a fourth force to each of the multiple secondary charged particle beams, respectively, and the third force and the fourth force are opposite to each other and form corresponding first-order beam dispersions.

[0195] 45. The method according to Clause 44 further includes:

[0196] Multiple primary beam dispersions are adjusted to eliminate the influence of multiple secondary beam dispersions generated by the beam splitter on multiple secondary detection points formed by multiple secondary charged particle beams on the detection device.

[0197] 46. ​​A dispersive filter for a charged particle beam system, the dispersive filter being disposed upstream of a beam splitter in the charged particle beam system, and comprising:

[0198] The combination of electrostatic deflectors and magnetic deflectors is configured to induce a first beam dispersion that is substantially opposite to the second beam dispersion caused by the beam splitter.

[0199] It should be understood that the present invention is not limited to the exact construction described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from the scope of the invention. The scope of the invention should be limited only by the appended claims.

Claims

1. A dispersion device for a charged particle beam system having a beam splitter and an objective lens, the dispersion device comprising: Electrostatic deflectors and magnetic deflectors are configured to induce a first beam dispersion on a beam of charged particles incident on a sample of the system, wherein the first beam dispersion is adjusted to eliminate the effect of a second beam dispersion caused by a beam splitter. An electrostatic deflector is configured to apply a first force to the charged particle beam, and a magnetic deflector is configured to apply a second force to the charged particle beam. The first and second forces are substantially opposite to each other and form a first beam dispersion. When the dispersion of the first beam is changed relative to the dispersion of the second beam, the beam deflection angle caused by the dispersion device remains unchanged, and The adjustment of the first beam dispersion causes an adjustment of the position of the object plane associated with the objective lens, which is a virtual focal plane of a portion of the charged particles in the charged particle beam.

2. The dispersing device according to claim 1, wherein the deflection angle is zero.

3. The dispersion device according to claim 1, further comprising a multipole lens capable of generating a quadrupole field to eliminate the effects of astigmatism caused by the first force and the second force.

4. The dispersion device according to claim 3, wherein the multipole lens is positioned adjacent to one of the beam splitter and the dispersion device.

5. The dispersion device according to claim 1, wherein the charged particle beam is an electron beam.

6. The dispersion apparatus according to any one of claims 1 to 4, wherein the charged particle beam system includes an electron beam inspection tool.

7. The dispersion device according to claim 1, wherein the dispersion device is arranged upstream of the beam splitter of the charged particle beam system.

8. A charged particle beam device, comprising: Source, used to generate primary charged particle beams; A first dispersing device is located below the source; The beam splitter is located below the first dispersing device; Objective lens, located below the beam splitter; Sample stage, used to support the sample; as well as The detector is located above the beam splitter. The primary charged particle beam is focused onto the sample through the objective lens, forming a primary detection point thereon, and thereby generating a secondary charged particle beam. The beam splitter is configured to separate the primary charged particle beam and the secondary charged particle beam, such that the secondary charged particle beam is detected by the detector. The first dispersing device is configured to generate a first primary beam dispersion on the primary charged particle beam, and the beam splitter is configured to generate a second primary beam dispersion on the primary charged particle beam and a second secondary beam dispersion on the secondary charged particle beam. The first dispersion device includes a first electrostatic deflector and a first magnetic deflector, respectively configured to apply a first force and a second force to the primary charged particle beam, wherein the first force and the second force are opposite to each other and form the first primary beam dispersion. The adjustment of the first primary beam dispersion eliminates the influence of the second primary beam dispersion on the primary detection point. Furthermore, the adjustment of the first primary beam dispersion causes an adjustment of the position of the object plane associated with the objective lens, the object plane being a virtual focal plane of a portion of the charged particles in the primary charged particle beam. When the dispersion of the first primary beam is changed relative to the dispersion of the second primary beam, the first deflection angle of the primary charged particle beam caused by the first dispersion device remains unchanged.

9. The charged particle beam device of claim 8, wherein the beam splitter is configured to further deflect the primary charged particle beam to a second deflection angle based on the energy of the charged particles of the primary charged particles.

10. The charged particle beam apparatus of claim 9, wherein the first deflection angle of the primary charged particle beam caused by the first dispersing device is equal to and opposite to the second deflection angle of the primary charged particle beam caused by the beam splitter.

11. The charged particle beam device according to claim 9, wherein the first deflection angle of the primary charged particle beam caused by the first dispersing device is zero.

12. The charged particle beam apparatus of claim 8, further comprising one or more secondary charged particle beam deflectors between the beam splitter and the detector, and the one or more secondary charged particle beam deflectors being configured to adjust at least one of the position and angle of the secondary charged particle beam incident on the detector.

13. The charged particle beam apparatus of claim 8 or 12, further comprising a second dispersion device between the beam splitter and the detector, and configured to generate a first-order beam dispersion of the secondary charged particle beam, the second dispersion device comprising: The third electrostatic deflector and the third magnetic deflector, wherein the adjustment of their corresponding deflection fields causes the first-stage beam dispersion to eliminate the influence of the second-stage beam dispersion on the secondary detection point of the secondary charged particle beam on the detector.

14. A method for controlling dispersion in a charged particle beam system having a beam splitter and an objective lens, comprising: A first dispersion device is provided in the path of the primary charged particle beam of the system; The first dispersing device is placed upstream of the beam splitter; The first primary beam dispersion of the primary charged particle beam is generated by the first dispersion device; as well as The first primary beam dispersion is adjusted to eliminate the effect of the second primary beam dispersion of the primary charged particle beam caused by the beam splitter, and the position of the object plane associated with the objective lens is adjusted, the object plane being a virtual focal plane of a portion of the charged particles of the primary charged particle beam. The first dispersion device includes a first electrostatic deflector and a first magnetic deflector that apply a first force and a second force to the primary charged particle beam, respectively, wherein the first force and the second force are opposite to each other and form the first primary beam dispersion. When the dispersion of the first primary beam is changed relative to the dispersion of the second primary beam, the deflection angle of the primary charged particle beam caused by the first dispersing device remains unchanged.

15. A dispersive filter for a charged particle beam system, the dispersive filter being disposed upstream of a beam splitter and an objective lens of the charged particle beam system, and comprising: The combination of electrostatic and magnetic deflectors is configured to induce a first beam dispersion that is substantially opposite to the second beam dispersion induced by the beam splitter. When the electrostatic dipole field and the magnetic dipole field are adjusted to control the change in the dispersion of the first beam relative to the dispersion of the second beam, the beam deflection angle caused by the dispersion filter remains unchanged, and The first beam dispersion adjustment operation is used to adjust the position of the object plane associated with the objective lens, the object plane being a virtual focal plane of a portion of the charged particles in the charged particle beam.

16. The dispersive filter of claim 15, wherein the combination of the electrostatic deflector and the magnetic deflector generates an electrostatic dipole field and a magnetic dipole field, wherein the electrostatic dipole field and the magnetic dipole field are substantially perpendicularly superimposed on each other and perpendicular to the optical axis of the charged particle beam system.

17. The dispersive filter of claim 16, wherein the electrostatic dipole field and the magnetic dipole field apply a first force and a second force to a beam of charged particles propagating along the optical axis, the first force and the second force being substantially opposite to each other and forming the first beam dispersion.

18. The dispersive filter of claim 15, wherein the deflection angle is zero.

19. The dispersive filter of claim 17, further comprising a multipole lens capable of generating a quadrupole field to eliminate the effects of astigmatism caused by the first force and the second force.

20. The dispersive filter of claim 19, wherein the multipole lens is contained within the dispersive filter or the beam splitter.

21. The dispersive filter of claim 15, wherein the charged particle beam is an electron beam.

22. The dispersive filter of claim 15, wherein the charged particle beam system includes an electron beam inspection tool.

23. The dispersive filter of claim 15, wherein the beam splitter comprises a Wien filter.

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