CN115485804A

CN115485804A - Device for manipulating a charged particle beam using an enhanced deflector

Info

Publication number: CN115485804A
Application number: CN202180032940.7A
Authority: CN
Inventors: 王勇新; 董仲华; 季晓宇; 沙赫杜尔·霍克; 任伟明; 刘学东; 叶国凡; 简国晋
Original assignee: ASML Holding NV
Current assignee: ASML Holding NV
Priority date: 2020-03-20
Filing date: 2021-03-18
Publication date: 2022-12-16
Also published as: US20230178328A1; WO2021185938A1

Abstract

An apparatus comprises a first charged particle beam manipulator positioned in a first layer configured to influence a charged particle beam and a second charged particle beam manipulator positioned in a second layer configured to influence a charged particle beam. The first charged particle beam manipulator and the second charged particle beam manipulator may each comprise a plurality of electrodes having a first set of opposing electrodes and a second set of opposing electrodes. A first driver system electrically connected to the first group may be configured to provide a plurality of discrete output states to the first group. A second driver system electrically connected to the second group may be configured to provide a plurality of discrete output states to the second group. The first charged particle beam manipulator and the second charged particle beam manipulator may each comprise a plurality of segments; and a controller having circuitry configured to individually control operation of each of the plurality of segments.

Description

Device for manipulating a charged particle beam using an intensifying deflector

Cross Reference to Related Applications

This application claims priority from U.S. application 62/992,870, filed on 20/2020, and U.S. application 63/145,694, filed on 4/2/2021, which are incorporated herein by reference in their entirety.

Technical Field

Embodiments provided herein relate generally to inspection (inspection) devices, and more particularly to charged particle beam manipulation systems of inspection devices.

Background

During the manufacture of Integrated Circuits (ICs), incomplete or completed circuit components are inspected to ensure that they are manufactured as designed and are defect free. An inspection system using an optical microscope or a charged particle (e.g., electron) beam microscope, such as a Scanning Electron Microscope (SEM), may be employed. As the physical size of IC devices continues to shrink, the accuracy of defect detection in yield control becomes increasingly important. Although multiple beams may be used to increase throughput (throughput), the limitations of beam deflection may limit the imaging throughput required for reliable defect inspection and analysis, thereby making the inspection tool insufficient to meet its desired throughput.

As devices continue to shrink and the structure of IC chips becomes more complex, inspection and metrology systems have made significant advances, such as multi-beam inspection, multi-detector, etc., to improve wafer inspection throughput, etc. A charged particle probe beam with low landing energy (landing energy) provides surface related information, while a probe beam with high landing energy can be used to extract information from the buried layer. To achieve high overall wafer inspection throughput, it may be desirable to increase the scan field of view for both low landing energy and high landing energy modes. Achieving a large field of view at high landing energies may include optimization of the scan deflection system and associated electronic circuit design. While existing systems may achieve high throughput for low landing energy checks, they have difficulty in achieving high throughput while maintaining image quality.

Disclosure of Invention

Some embodiments of the present disclosure may provide a single beam inspection apparatus or a multi-beam inspection apparatus, and more particularly, may provide a single beam inspection apparatus or a multi-beam inspection apparatus including a scanning deflection system. In some embodiments, an apparatus is provided that includes a first charged particle beam manipulator comprising a plurality of layers. The manipulator may be configured to influence the charged particle beam. The charged particle beam may be an electron beam. The apparatus also includes a plurality of electrodes having a first set of opposing electrodes and a second set of opposing electrodes, a first driver system electrically connected to the first set of opposing electrodes and configured to provide a plurality of discrete output states to the first set of opposing electrodes, and a second driver system electrically connected to the second set of opposing electrodes and configured to provide a plurality of discrete output states to the second set of opposing electrodes. Further, each of the plurality of layers may include a plurality of electrodes, a first driver system, and a second driver system.

In some embodiments, a method of dynamically deflecting an electron beam is provided. The method includes controlling a first set of opposing electrodes to affect the electron beam using a first driver system, and controlling a second set of opposing electrodes to affect the electron beam using a second driver system, wherein the first driver system, the first set of opposing electrodes, the second driver system, and the second set of opposing electrodes are implemented in a first layer.

In some embodiments, a non-transitory computer-readable medium is provided that includes a set of instructions executable by one or more processors of a controller to cause the controller to perform a method for dynamically deflecting an electron beam. The method includes instructing a first driver system connected to a first set of opposing electrodes to control a first set of output states to affect the electron beam, and instructing a second driver system connected to a second set of opposing electrodes to control a second set of output states to affect the electron beam, wherein the first driver system, the first set of opposing electrodes, the second driver system, and the second set of opposing electrodes may be implemented in a first layer.

Some aspects of the present disclosure relate to a charged particle beam apparatus comprising a first charged particle beam deflector configured to influence a primary charged particle beam generated by a charged particle source along a primary optical axis; a second charged particle beam deflector positioned downstream of the first charged particle beam deflector and configured to influence the primary charged particle beam, wherein the first charged particle beam deflector and the second charged particle beam deflector each comprise a plurality of segments; and a controller having circuitry configured to individually control the operation of each of the plurality of segments.

Some aspects of the present disclosure relate to a charged particle beam apparatus, the apparatus comprising a first charged particle beam deflector configured to influence a primary charged particle beam generated by a charged particle source along a primary optical axis; a second charged particle beam deflector positioned downstream of the first charged particle beam deflector and configured to affect the primary charged particle beam, wherein the first charged particle beam deflector and the second charged particle beam deflector each comprise: an electrostatic deflector electrically connected to a first driver system, the first driver system configured to enable the electrostatic deflector to deflect the primary charged particle beam; and a magnetic deflector electrically connected to a second driver system, the second driver being configured to enable the magnetic deflector to deflect the primary charged particle beam.

Some aspects of the present disclosure relate to a method for deflecting a primary charged particle beam passing through a deflection scanning unit of a charged particle beam device. The method may comprise deflecting a primary charged particle beam generated by a charged particle source along a primary optical axis using a first charged particle beam deflector; deflecting the primary charged particle beam using a second charged particle beam deflector positioned downstream of the first charged particle beam deflector, wherein the first charged particle beam deflector and the second charged particle beam deflector each comprise a plurality of segments; and individually controlling the operation of each segment of the plurality of segments using a controller having circuitry.

Some aspects of the present disclosure relate to a method for deflecting a primary charged particle beam passing through a deflection scanning unit of a charged particle beam device. The method may comprise deflecting a primary charged particle beam generated by a charged particle source along a primary optical axis using a first charged particle beam deflector; deflecting the primary charged particle beam using a second charged particle beam deflector positioned downstream of the first charged particle beam deflector, wherein the first charged particle beam deflector and the second charged particle beam deflector each comprise: an electrostatic deflector electrically connected to a first driver system, the first driver system configured to enable the electrostatic deflector to affect the primary charged particle beam; and a magnetic deflector electrically connected to a second driver system configured to enable the magnetic deflector to affect the primary charged particle beam.

Some aspects of the present disclosure relate to a non-transitory computer readable medium having stored thereon a set of instructions executable by one or more processors of a charged particle beam device to cause the charged particle beam device to perform a method of deflecting a primary charged particle beam passing through a deflection scanning unit of the charged particle beam device. The method can comprise the following steps: deflecting said primary charged particle beam generated by a charged particle source along a main optical axis using a first charged particle beam deflector; deflecting the primary charged particle beam using a second charged particle beam deflector positioned downstream of the first charged particle beam deflector, wherein the first charged particle beam deflector and the second charged particle beam deflector each comprise a plurality of segments; and individually controlling operation of each of a plurality of segments, each segment configured to deflect a primary charged particle beam.

Some aspects of the present disclosure relate to a non-transitory computer readable medium having stored thereon a set of instructions executable by one or more processors of a charged particle beam device to cause the charged particle beam device to perform a method of deflecting a primary charged particle beam passing through a deflection scan unit of the charged particle beam device. The method can comprise the following steps: deflecting a primary charged particle beam generated by a charged particle source along a primary optical axis using a first charged particle beam deflector; deflecting the primary charged particle beam using a second charged particle beam deflector located downstream of the first charged particle beam deflector, wherein the first charged particle beam deflector and the second charged particle beam deflector each comprise: an electrostatic deflector electrically connected to a first driver system, the first driver system configured to enable the electrostatic deflector to affect the primary charged particle beam; and a magnetic deflector electrically connected to a second driver system configured to enable the magnetic deflector to affect the primary charged particle beam.

Other advantages of embodiments of the present disclosure will become apparent from the following description taken in conjunction with the accompanying drawings, in which certain embodiments of the invention are set forth by way of illustration and example.

Drawings

Fig. 1 is a diagram illustrating an exemplary charged particle beam inspection system, according to an embodiment of the present disclosure.

Fig. 2 is a diagram illustrating an example multi-beam apparatus as part of the example electron beam inspection system of fig. 1, in accordance with an embodiment of the present disclosure.

Fig. 3A is a diagram illustrating a configuration of a scanning deflection system according to an embodiment of the present disclosure.

Fig. 3B is a diagrammatic representation of deflection of a charged particle beam in accordance with an embodiment of the present disclosure.

Fig. 3C is a diagram illustrating a configuration of an exemplary deflecting element according to an embodiment of the present disclosure.

Fig. 4A is a diagram showing a plan view of an illustrative embodiment of a deflection system that may be implemented in a deflection scanning unit in a single beam or multi-beam inspection system, according to an embodiment of the present disclosure.

Fig. 4B is a diagram showing a cross-sectional view of an illustrative embodiment of a deflection system in multiple layers that may be implemented in a deflection scanning unit in a single-beam or multi-beam inspection system, according to an embodiment of the present disclosure.

Fig. 4C is a diagram showing a cross-sectional view of another illustrative embodiment of a deflection system in multiple layers, which may be implemented in a deflection scanning unit in a single-beam or multi-beam inspection system.

Fig. 4D is a diagram illustrating a plan view of an embodiment of a deflection system of a manipulator having a smaller diameter than that of fig. 4A, according to an embodiment of the present disclosure.

Fig. 4E is a diagram showing a cross-sectional view of an illustrative embodiment of a deflection system in multiple layers, which may be implemented in a deflection scanning unit in a single-beam or multi-beam inspection system.

FIG. 4F is a diagram showing a cross-sectional view of another illustrative embodiment of a deflection system in multiple layers, which may be implemented in a deflection scanning unit in a single-beam or multi-beam inspection system.

FIG. 4G is a diagram showing a cross-sectional view of another illustrative embodiment of a deflection system in multiple layers, which may be implemented in a deflection scanning unit in a single-beam or multi-beam inspection system.

Fig. 5A is a diagram illustrating a driver according to an embodiment of the present disclosure.

Fig. 5B is a diagram illustrating a plurality of drivers according to an embodiment of the present disclosure.

FIG. 6 is a flow chart illustrating an exemplary method for controlling a driver associated with a deflection system according to an embodiment of the present disclosure.

Fig. 7A is a schematic diagram illustrating an exemplary configuration of a charged particle beam device including a plurality of charged particle beam deflectors according to an embodiment of the present disclosure.

Fig. 7B is a schematic diagram illustrating an exemplary configuration of the segmented charged particle beam deflector of fig. 7A, in accordance with an embodiment of the present disclosure.

Fig. 7C is a schematic diagram illustrating an exemplary configuration of control circuitry associated with a segmented charged particle beam deflector, according to an embodiment of the present disclosure.

Fig. 7D is a schematic diagram illustrating an exemplary deflection field distribution of a charged particle beam deflector according to an embodiment of the present disclosure.

Fig. 7E is a schematic diagram illustrating another exemplary deflection field distribution of a charged particle beam deflector, according to an embodiment of the present disclosure.

Figures 8A-8C are schematic diagrams illustrating exemplary configurations of control circuitry associated with a hybrid charged particle beam deflector, according to embodiments of the present disclosure.

Fig. 8D is a schematic diagram of an exemplary configuration of a hybrid beam deflector according to an embodiment of the present disclosure.

Fig. 9A-9B are schematic diagrams illustrating an exemplary configuration of a charged particle beam device including an adjustable sample stage, according to an embodiment of the present disclosure.

Fig. 10 is a process flow diagram illustrating an exemplary method for deflecting a charged particle beam through a deflection scanning unit of a charged particle beam device in accordance with an embodiment of the present disclosure.

Fig. 11 is a process flow diagram illustrating another exemplary method for deflecting a charged particle beam through a deflection scanning unit of a charged particle beam device in accordance with an embodiment of the present disclosure.

Detailed Description

Reference will now be made in detail to the illustrative embodiments, examples of which are illustrated in the accompanying drawings. The following description refers to the accompanying drawings, in which the same reference numbers in different drawings identify the same or similar elements. The embodiments set forth in the following description of illustrative embodiments do not represent all embodiments according to the present invention. Rather, they are merely examples of apparatus and methods according to aspects of the invention described in the appended claims. For example, although some embodiments are described in the context of utilizing an electron beam, the disclosure is not so limited. Other types of charged particle beams may be similarly applied. In addition, other imaging systems may also be used, such as optical imaging, light detection, x-ray detection, and the like.

Electronic devices are made up of circuits formed on a piece of silicon, called a substrate. Many circuits may be formed together on the same piece of silicon and are referred to as an integrated circuit or IC. The size of these circuits has decreased dramatically so that more circuits can be mounted on the substrate. For example, an IC chip in a smartphone may be as small as a thumb nail, but may include more than 20 hundred million transistors, each of which is less than 1/1000 the size of human hair.

Manufacturing these extremely small ICs is a complex, time consuming and expensive process, typically involving hundreds of individual steps. Even if an error occurs in one step, it may cause defects in the finished IC, rendering it useless. Therefore, one goal of the manufacturing process is to avoid such defects to maximize the number of functional ICs manufactured in the process, i.e., to improve the overall yield of the process.

One component that improves yield is monitoring the chip manufacturing process to ensure that it produces a sufficient number of functional integrated circuits. One way to monitor this process is to inspect the chip circuit structure at various stages of its formation. The examination may be performed using a Scanning Electron Microscope (SEM). SEMs can be used to image these extremely small structures, and in fact, can take "photographs" of these structures. The image may be used to determine whether the structure is formed correctly and in the correct location. If the structure is defective, the process can be adjusted to reduce the likelihood of the defect reoccurring.

Although charged particle beam imaging systems (such as single-beam SEMs or multi-beam SEMs) can help to improve yield, achieving higher throughput that needs to be achieved may result in higher complexity and higher power consumption of high speed scanning deflection systems. The disclosed deflecting structures may be configured to enable the beam to scan a large surface of a sample at high speed with low distortion. SEM uses deflecting structures to direct a beam to scan a surface to create an image of a sample. The deflection structure requires that the deflection driver generates various voltages within a predefined range to generate an electromagnetic field to enable the beam to be steered.

To make a scanning deflection system, conventional systems use either carefully designed and constructed linear amplifiers and digital-to-analog converters (DACs) or continuous-time sawtooth generators. The use of conventional yaw drive assemblies is undesirable because they can cause problems. For example, conventional deflection driver components are more complex, leading to reliability issues, increased noise levels in various situations, and increased power consumption, which may stress the SEM.

Some embodiments of the present disclosure may relate to an electron beam scanning deflection system. A scanning deflection system may be used for dynamic deflection. In some embodiments of the present disclosure, a charged particle beam inspection system includes an improved deflection structure having a driver system configured to manipulate the beam. Instead of analog amplifiers and DACs or continuous-time sawtooth generators, which may be required by conventional techniques, the driver system may use multiple high voltage power supplies, or high speed and high voltage switches, to steer the beam. The high voltage power supply may provide a static high voltage output having a predefined value. The high speed and high voltage switch can provide the high voltage(s) needed to supply the deflector (electrodes).

For example, the high speed and high voltage switches may replace high voltage linear amplifiers and digital-to-analog converters (DACs) or continuous time sawtooth signal generators. This alternative may simplify the circuit design of the driver system, since fewer components are required to build the switch compared to a high voltage linear amplifier. Furthermore, a digital-to-analog converter or a continuous-time sawtooth signal generator may not be needed, since the configuration transmitted in the form of a digital signal from the controller of the charged particle beam inspection system may be directly applied to a switch connected to a high voltage regulator, which provides a static high voltage output.

In some embodiments, the deflection structure and driver system may provide several advantages by operating the active device in a switching mode rather than a linear mode, where the active device may control and power the deflection structure. The trade-off between linearity, speed and power consumption (as in conventional scanning deflection systems) can be reduced or avoided. First, the deflection structure can regulate the voltage provided by the power supply faster because the high speed and high voltage switches can be built more easily than the high voltage and high speed linear amplifiers, and the switches can reach higher speeds, using the same components or processes. This may enable faster steering of the beam. Second, the scanning deflection system can also provide more accurate control input signals (e.g., linearity) because the switch-mode active devices in the driver system can provide the desired voltages to the deflection structure even at high speeds. Third, the scanning deflection system can use less power. Therefore, energy waste can be reduced. By closing or opening the high speed high voltage switch, the active device in the switch mode consumes less power than the passive device in the linear mode. Thus, the switch mode active device simplifies the thermal management of the charged particle beam inspection system. And fourth, the disclosed drive system can improve the overall reliability of the charged particle beam inspection system by using fewer components. The circuitry of the driver system is simplified, thereby improving the overall reliability of the SEM.

In support of advances in chip design and device design, the limits of electron beam inspection and metrology systems in wafer fabrication plants are constantly being driven. Due to the complex 3D structures employed in devices such as 3D NAND, finFET, DRAM, etc., defects may be buried deeper within the substrate and secondary electron microscopes that provide surface level information may be inadequate and often misleading. An electron beam with high landing energy can penetrate the secondary surface layer and provide more information about the more deeply embedded defects and structures within the substrate. However, some of the problems encountered when using high landing energy electron beams include the generation of backscattered electrons with low detection and sampling rates, a smaller field of view (FOV), poor image quality, and low throughput compared to low landing energy electron beams. Furthermore, as landing energy increases, high landing energy beam systems may also encounter challenges in driver circuit design because beam deflection requires extremely high voltages to maintain the FOV. Accordingly, it may be desirable to provide systems and methods for acquiring a large FOV for low and high landing energies while maintaining high image quality and high output for defect inspection and overlay metrology.

Some embodiments of the present disclosure relate to an apparatus and method for deflecting a primary electron beam using a segmented deflector. The method may comprise deflecting the primary electron beam with two or more deflectors, each deflector comprising a plurality of segments. Each of the plurality of segments may include a multi-pole structure (multipole) including a plurality of electrodes configured to deflect the primary electron beam. The segments may be electronically driven using dedicated driver systems or driver circuitry capable of supporting the scan frequency and driver linearity to deflect the beam sufficiently to form a large FOV.

Other objects and advantages of the present disclosure may be realized by means of the elements and combinations set forth in the embodiments discussed herein. However, embodiments of the present disclosure need not achieve such exemplary objectives or advantages, and some embodiments may not achieve any of the stated objectives or advantages.

Without limiting the scope of the present disclosure, some embodiments may be described in the context of providing a scanning deflection system and a scanning deflection method in a system utilizing electron beams ("e-beams"). Some scanning deflection systems may use electric fields to influence the charged particle beam. However, the present disclosure is not limited thereto. Other types of charged particle beams may be similarly applied. For example, the systems and methods may be applicable to optics, photons, x-rays, ions, and the like. Deflection may be used to scan the beam over a surface in a Cathode Ray Tube (CRT), a lithography machine, a Scanning Electron Microscope (SEM), or other analytical instrument. Although some embodiments are discussed with reference to a deflection system using an electric field to influence the beam, the deflection may also be realized by a magnetic field, for example.

Referring now to fig. 1, fig. 1 is a schematic diagram illustrating an exemplary charged particle beam inspection system 1, according to an embodiment of the present disclosure. As shown in fig. 1, the charged particle beam inspection system 1 includes a main chamber 10, a load/lock chamber 20, an electron beam tool 100, and an Equipment Front End Module (EFEM) 30. The electron beam tool 100 is located within the main chamber 10. Although the description and drawings are directed to electron beams, it should be understood that the embodiments are not intended to limit the disclosure to specific charged particles.

The EFEM30 includes a first load port 30a and a second load port 30b. The EFEM30 may include additional load port(s). For example, the first and

second load ports

30a and 30b may receive a wafer front opening transfer pod (FOUP) that contains a wafer (e.g., a semiconductor wafer or a wafer made of other material (s)) or a sample to be inspected (wafer and sample are hereinafter collectively referred to as "wafer"). One or more robotic arms (not shown) in the EFEM30 transport the wafers to the load/lock chamber 20.

The load/lock chamber 20 may be connected to a load/lock vacuum pumping system (not shown) that may remove gas molecules in the load/lock chamber 20 to a first pressure below atmospheric pressure. After the first pressure is reached, one or more robotic arms (not shown) transport the wafer from load/lock chamber 20 to main chamber 10. The main chamber 10 is connected to a main chamber vacuum pumping system (not shown) that removes gas molecules in the main chamber 10 to reach a second pressure lower than the first pressure. After the second pressure is reached, the wafer is inspected by the electron beam tool 100. In some embodiments, the e-beam tool 100 may comprise a single beam inspection tool. In other embodiments, the e-beam tool 100 may comprise a multi-beam inspection tool.

The controller 50 is electrically connected to the e-beam tool 100. The controller 50 may be a computer configured to perform various controls of the charged particle beam inspection system 1. The controller 50 may also include processing circuitry configured to perform various signal and image processing functions. While the controller 50 is shown in FIG. 1 as being external to the structure including the main chamber 10, the load/lock chamber 20 and the EFEM30, it is understood that the controller 50 may be part of the structure. Although the present disclosure provides an example of a main chamber 10 housing an electron beam inspection tool, it should be noted that the broadest aspects of the present disclosure are not limited to a chamber housing an electron beam inspection tool. Rather, it should be understood that the principles described above may also be applied to other tools that operate at a second pressure (under the second pressure).

Referring now to fig. 2, fig. 2 shows a schematic diagram of an exemplary electron beam tool 100, the electron beam tool 100 comprising a multi-beam inspection tool as part of the exemplary charged particle beam inspection system 1 of fig. 1, in accordance with an embodiment of the present disclosure. The electron beam tool 100 (also referred to herein as the apparatus 100) includes an electron source 101, a gun aperture plate (gun aperture plate) 171, a condenser lens 110, a source conversion unit 120, a main projection optical system 130, a sample stage (not shown in fig. 2), an auxiliary optical system 150, and an electron detection device 140M. The main projection optical system 130 may include an objective lens 131. The electronic detection device 140M may include a plurality of detection elements 140 u 1, 140 u 2, and 140 u 3. The beam splitter 160 and the deflection scanning unit 132 may be disposed inside the main projection optical system 130.

The electron source 101, the gun aperture plate 171, the condenser lens 110, the source conversion unit 120, the beam splitter 160, the deflection scanning unit 132, and the main projection optical system 130 may be aligned with the main optical axis 100_1 of the apparatus 100. The secondary optical system 150 and the electronic detection device 140M may be aligned with a secondary optical axis 150_1 of the apparatus 100.

The electron source 101 may comprise a cathode (not shown) and an extractor (extractor) or an anode (not shown), wherein during operation the electron source 101 is configured to emit primary electrons from the cathode, and the primary electrons are extracted or accelerated by the extractor and/or the die anode to form a primary electron beam 102, the primary electron beam 102 forming a primary electron beam intersection (virtual or real) 101s. The primary electron beam 102 may be visualized as being emitted from the intersection 101s.

The source conversion unit 120 may include an image forming element array (not shown in fig. 2), a field curvature compensator array (not shown in fig. 2), a dispersion compensator array (not shown in fig. 2), and a beam limiting aperture array (not shown in fig. 2). The image forming element array may include a plurality of micro deflectors or micro lenses to form a plurality of parallel images (virtual or real) of the intersection 101s using a plurality of electron beams (e.g., beam waves) of the primary electron beam 102. The field curvature compensator array may comprise a plurality of micro lenses to compensate for field curvature aberrations of the primary electron beams. The astigmatism (astigmatism) compensator array may comprise a plurality of micro-diffusers (stigmator) to compensate for astigmatic aberrations of the primary electron beams. The beam limiting aperture array may limit a plurality of electron beams. Fig. 2 shows three electron beams 102 \, 2 and 102 \, 3 as an example, but it should be understood that the source conversion unit 120 may be configured to form any number of electron beams.

The controller 50 may be connected to various components of the charged particle beam inspection system 1 of fig. 1, such as the source conversion unit 120, the electron detection device 140M, or the main projection optical system 130. More specifically, the controller 50 may be connected to the deflection scanning unit 132. In some embodiments, the controller 50 may perform various processing functions, as described in further detail below. The controller 50 may also generate various control signals to control the operation of the charged particle beam inspection system.

The condenser lens 110 may focus the primary electron beam 102. The current of the electron beams 102_1, 102_2, and 102 _3downstream of the source conversion unit 120 may be varied by adjusting the focusing power of the condenser lens 110 or by changing the radial size of the corresponding beam limiting apertures within the array of beam limiting apertures. The objective lens 131 may focus the electron beams 102_1, 102_2, and 102 _3onto the sample 190 for inspection, and may form detection points 102_1s, 102_2s, and 102 _3son the surface of the sample 190. The gun aperture plate 171 may block peripheral electrons of the unused primary electron beam 102 to reduce coulomb effects. The coulomb effect increases the size of each of the detection points 102_1s, 102_2s, and 102_3s, and thereby reduces the detection resolution.

The beam splitter 160 may be a Wien (Wien) filter type beam splitter including an electrostatic deflector that generates an electrostatic dipole field E1 and a magnetic dipole field B1 (both not shown in fig. 2). If they are applied, the force exerted by the electrostatic dipole field E1 on the electrons of electron beams 102_1, 102_2, and 102 _3is equal in magnitude and opposite in direction to the force exerted by the magnetic dipole field B1 on the electrons. Thus, electron beams 102_1, 102_2, 102 _3may have a zero deflection angle and pass directly through beam splitter 160.

The deflection scanning unit 132 can deflect the electron beams 102_1, 102_2, and 102 _3to scan the detection points 102_1s, 102_2s, and 102 _3sover a scanning area in a section of the surface of the sample 190. In response to the incidence of the electron beams 102_1, 102_2, 102 _3at the detection points 102_1s, 102_2s, and 102_3s, secondary electron beams 102_2se, and 102 _3semay be emitted from the sample 190. Each of the secondary electron beams 102_1se, 102_2se, and 102 _3semay include electrons having an energy distribution including secondary electrons and backscattered electrons. Beam splitter 160 may direct secondary electron beams 102_1se, 102_2se, and 102 _3setoward secondary optics 150. The secondary optical system 150 may focus the secondary electron beams 102_1se, 102_2se, 102 _3seonto the detection elements 140_1, 140_2, and 140 _3of the electronic detection device 140M. The detection elements 140_1, 140_2, and 140 _3may detect the corresponding secondary electron beams 102_1se, 102_2se, and 102 _3seand generate corresponding signals for reconstructing an image of the corresponding scanned area of the sample 190.

In some embodiments, the scanning deflection system may be applied to a deflection scanning unit of a single-beam or multi-beam charged particle beam system. For example, the deflection scanning unit 132 (see fig. 2) may include an electron beam scanning deflection system.

Referring now to fig. 3A, fig. 3A illustrates a configuration of a deflector and objective lens assembly according to an embodiment of the present disclosure. As shown in FIG. 3A, magnetic objective lens assembly 310 and deflectors 309-1 and 309-2 may be disposed within the magnetic field of objective lens assembly 320, where deflectors 309-1 and 309-2 may be implemented in a deflecting scanning unit (e.g., deflecting scanning unit 132 of FIG. 2). Deflectors 309-1 and 309-2 may be configured to dynamically deflect the electron beam to scan a desired area on the surface of sample 308. Dynamic deflection of the electron beam may cause the desired region or desired regions of interest to be iteratively scanned, for example, in a raster (raster) scan mode, to generate secondary electron beams (e.g., 102_1se, 102_2se, and 102 _3seof fig. 2) for examination of the sample. The deflector 309-1 or 309-2 may be configured to deflect the electron beam in the X-axis or Y-axis direction. As used herein, the X-axis and Y-axis form cartesian coordinates of an arbitrary reference frame in which the electron beam may propagate along the Z-axis or main optical axis 304. In the views of fig. 2 or fig. 3A, the X-axis refers to a horizontal or transverse axis extending along the width of the sheet, and the Y-axis refers to a vertical axis extending in and out of the plane of the sheet.

Referring now to fig. 3B, fig. 3B shows a representation of a charged particle beam passing through a deflector, according to an embodiment of the present disclosure. In some embodiments, the charged particle beam may be deflected as it passes through the region between a pair of electrodes. As shown in fig. 3B, the charged particle beam 320 can travel along an axis 350. Axis 350 may be aligned with the Z-axis of the charged particle beam system.

Electrodes

335 and 345 may be disposed on either side of axis 350. A voltage may be applied to

electrodes

335 and 345. An electric field may be formed between the electrodes, the electric field component being substantially perpendicular to the direction of travel of the charged particle beam 320. As the charged particle beam 320 travels through the resulting electric field, it may be affected by the electric field. For example, its trajectory may change. The deflection scanning unit may deflect the beam using a deflector to scan the beam across an area on the sample.

Referring now to fig. 3C, fig. 3C is a diagram illustrating an electrode configuration according to an embodiment of the present disclosure. FIG. 3C shows a multipole structure having four electrodes e1-e4, the four electrodes e1-e4 may be configured to operate differently based on the voltage applied to each electrode. The electrodes e1-e4 may be used to form a deflector. In some embodiments, a deflection voltage may be formed between opposing pairs of electrodes (e.g., the pair formed by electrodes e2 and e 4; or the pair formed by electrodes e1 and e 3). Multiple pairs of electrodes may be combined so that deflection in a two-dimensional plane is possible. The deflector may be located in the region of the objective lens in the SEM system. The deflector may be used to dynamically direct the beam to a desired location on the sample surface. In some embodiments, there may be multiple beams that may be directed to multiple locations on the sample surface.

In some embodiments, the deflector may be used for other functions. In some cases, for example in the case of microlenses or microdiffusers, a static drive voltage may typically be applied to the deflector. Such deflectors can also operate dynamically at high speeds, for example, when switching rapidly between different operating conditions. Accordingly, it may be useful to apply aspects of the present disclosure (e.g., deflector and driver designs) to such deflectors. In one case, the multipole structure may be configured to act as a microlens when one voltage is applied to all of the electrodes. The multipole structure may be configured to act as a micro-imager when two voltages of the same absolute value but opposite directions are applied to the two pairs of opposing electrodes. For example, in FIG. 3C, the multipole structure acts as a microimager when V1 is applied to electrodes e1 and e3, and when-V1 is applied to electrodes e2 and e 4. And when zero voltage is applied to one pair of opposing electrodes and two voltages of the same absolute value but opposite polarity are applied to the other pair of opposing electrodes, the multipole structure can be configured to act as a micro-deflector. For example, in FIG. 3C, the multipole structure acts as a micro-deflector when 0V is applied to e2 and e4, V2 is applied to e1, and-V2 is applied to e 3. When used as a micro-deflector, the deflection angle of the electron beam increases with an increase in V2. In some cases, the micro-deflector may be configured to use a two-dimensional deflection function or more. Fig. 3C shows four electrodes configured in a multi-polar configuration as an example, it being understood that the multi-polar configuration may be configured to form more than four electrodes.

Referring now to fig. 4A, fig. 4A shows a plan view of an illustrative embodiment of a deflection structure 400 implemented in an electron beam inspection system, in accordance with embodiments of the present disclosure. The electron beam inspection system may comprise a single beam or a multi-beam system. In some embodiments, the deflection structure 400 may be one of several deflection structures to be implemented in a scanning deflection system (e.g., the deflection scanning unit 132 of fig. 2) of an electron beam inspection system. The deflection structure 400 may be used to manipulate the electron beam.

The deflection system may include a deflection structure and a driver system. The deflecting structure may comprise a multi-polar structure. As shown in fig. 4A, deflection structure 400 includes multipole structure 410, first drive system 401y, and second drive system 402x. Multipole structure 410 includes a first set of opposing electrodes 411A-B and a second set of opposing electrodes 421A-B, the first set of opposing electrodes 411A-B and the second set of opposing electrodes 421A-B may be configured to deflect an electron beam in each deflection direction (e.g., x-direction or y-direction) based on an output state applied to each set. The output state may correspond to a voltage applied to the electrodes. Multipole structure 410 including electrode sets 411A-B and 412A-B may function as a dynamic deflector (e.g., which may perform the function of deflector 309-1 or 309-2 in fig. 3A) based on the voltages applied to electrodes 411A-B and 412A-B. For example, when first driver system 401y applies 0V to

electrodes

411A and 411B, and second driver system 402x applies V1 to electrode 412A and-V1 to electrode 412B, the electron beam is deflected in the x-direction. As a further example, when first driver system 401y applies V2 to electrode 411A and-V2 to electrode 411B, and second driver system 402x applies 0V to

electrodes

412A and 412B, the electron beam is deflected in the y-direction. When V1 and V2 increase, the deflection angle of the electron beam also increases. Fig. 4A shows four electrodes configured in multipole structure 410 as an example, it being understood that multipole structure 420 may be configured to form more than four electrodes. Further, FIG. 4A shows two sets of opposing electrodes 411A-B and 412A-B configured in multipole structure 410 as an example, it being understood that multipole structure 420 may be configured to form any number of sets of opposing electrodes (including one set).

In some embodiments, the electrode sets 411A-B and 412A-B may be formed in a substrate and include a plurality of beam manipulators in the substrate. For example, each beam manipulator may be electrically isolated from the other beam manipulators by a circular trench filled with an isolation material (e.g., CVD oxide). Within the circular area, the manipulator may be formed by etching any isolation trenches between the deflector holes and the etched electrodes, and sputtering a metal layer on the locations where the electrodes should be formed. The metal layers may form electrode sets 411A-B and 412A-B, and some layers may be used for a first set of electrodes while other layers may be used for a second set of electrodes.

The first driver system 401y is electrically connected to the first set of opposing electrodes 411A-B and is configured to provide a plurality of discrete output states to the first set of opposing electrodes 411A-B, and the second driver system 402x is electrically connected to the second set of opposing electrodes 412A-B and is configured to provide a plurality of discrete output states to the second set of opposing electrodes 412A-B. As described above with respect to multipole structure 410, each of

driver systems

401y and 402x is configured to enable one set of opposing electrodes (e.g., 411A-B and 412A-B) to deflect electrons in one direction by providing a plurality of discrete output states to a corresponding set of opposing electrodes. Each of the

driver systems

401y and 402x may include multiple power supplies and multiple switches. A switch may refer to an active device operating in a switching mode.

The power supply may be configured to provide a plurality of discrete output states. Alternatively, each of the plurality of power supplies may be configured to provide a discrete output state. For example, the driver 401y may be configured with power supplies that provide-100V, 0V, and +100V. As a further example, driver 401y may be configured with power supplies that provide-100V, -50V, 0V, +50V, and +100V.

The plurality of switches may be configured by the controller and transmit incoming discrete output states from the power supply to corresponding sets of opposing electrodes. A controller (e.g., controller 50 in fig. 1) may transmit a digital signal to apply the digital signal to turn on or off the switch to transmit an incoming discrete output state or to block the output state. For example, three switches may connect three tap points associated with the power source and a first set of opposing electrodes, and the controller may transmit a digital signal to select one of the three switches to transmit a desired output state from the power source corresponding to the selected switch. The plurality of switches may be MOS drivers capable of achieving fast switching of the output state.

Referring now to fig. 5A, fig. 5A shows a pictorial representation of a drive (e.g., drive system 401 y) according to an embodiment of the present disclosure. The driver system 401y may be configured to provide a plurality of output states. The output states may correspond to, for example, -100V, 0V and 100V. The driver system 401y may include a multiple output driver 440. The multi-output driver 440 may have a first output 441, a second output 442, and a third output 443.

Outputs

441, 442, 443 may correspond to-100V, 0V and 100V, respectively. The driver system 401y may further comprise a switching unit 450. The switching unit 450 may include a plurality of individual switches. The switching unit 450 may be configured to operate such that only one connection is allowed at a time. The switching unit 450 includes a first switch 451, a second switch 452, and a third switch 453. In the state shown in fig. 5A, only the third switch 453 is connected. The output of electrode 411A may thus be the output provided by third output 443.

Control signals may be provided to components of driver system 401y. As shown in fig. 5A, the controller 50 may be configured to control a driver system 401y. The controller 50 may be connected to the multi-output driver 440 and may be configured to instruct the multi-output driver 430 to operate. The controller 50 may be connected to the switching unit 450, and may be configured to instruct the switching unit 450 to operate. For example, the controller 50 may instruct the multi-output driver 440 to supply power and instruct the switching unit 450 to select one of the

switches

451, 452, 453 to be connected so that the output state is provided to the electrode 411A.

The plurality of switches may enable the deflection structure 400 to provide several advantages over conventional scan deflection drivers, including, for example, high voltage linear amplifiers and digital-to-analog converters (DACs) or continuous time sawtooth signal generators, among others. First, the deflection structure 400 can more quickly adjust the voltage provided by the power supply because the configuration of the controller 50 can be directly applied to the switches in the driver system, thereby enabling faster beam steering. In the conventional deflection structure, the configuration in the form of a digital signal transmitted from the controller must be further converted by a digital-to-analog converter to configure a high-voltage linear amplifier, thereby causing a delay. A trade-off between speed, linearity and power consumption, which can limit the performance of conventional scanning deflection systems, can be avoided. Furthermore, when operating in the switching mode, the active device can operate at a higher speed. Furthermore, compatibility may be improved since more high voltage active devices are typically designed to operate in a switched mode rather than a linear mode. Operating such devices in a linear mode may limit performance in terms of linearity and speed, especially when the devices are operated at high pressures.

Second, the deflection structure 400 can provide a more accurate control input signal (e.g., linearity) because the switch can provide the desired voltage to the deflection structure even at high speeds. On the other hand, when the predefined operating voltage of the amplifier is high, the linearity of the high voltage linear amplifier may be affected.

Third, active devices operating in the switching mode of the deflecting structure 400 may waste less power than active devices operating in the linear mode. On the other hand, active devices operating in linear mode may consume more power and linear amplifier based systems may be more difficult to maintain.

In some embodiments, each of the first drive system 401y and the second drive system 402x may include a plurality of physical drives. Each of the plurality of physical drivers may include a power supply providing a discrete output and a switch similar to that described above. The physical drivers may be configured to provide discrete output states to corresponding electrodes, such as electrodes 411A-B and 412A-B.

Referring now to fig. 5B, fig. 5B shows a schematic diagram of a plurality of drivers, according to an embodiment of the present disclosure. The driver system 401y may be configured to provide multiple output states by providing separate drivers that each produce an output. Each individual driver may be configured to provide its own output. The drive system 401y may include a first drive 461, a second drive 462, and a third drive 463. Each of the

drivers

461, 462, and 463 may be configured to be powered at a predetermined output.

Drivers

461, 462 and 463 are connected to

switches

451, 452 and 453, respectively. The controller 50 may be configured to operate the

switches

451, 452, and 453 individually. The controller 50 may be configured to operate the

drivers

461, 462 and 463 individually. The controller 50 may be configured to operate the switches such that only one switch is connected at a time. In the state shown in fig. 5B, only the third switch 453 is connected. Thus, the output of the electrode 411A may be provided only by the third driver 463.

Referring now to fig. 4B, fig. 4B shows a cross-sectional view of an illustrative embodiment of a deflection system 450 that may be used in an electron beam inspection system in accordance with embodiments of the present disclosure. The deflection system 450 includes deflection structures 450A-D, each in a corresponding layer. Each deflection structure 450A-D includes a manipulator or multipole structure (410A-D) and a plurality of driver systems (401 yA-D and 402 xA-D). In some embodiments, the multiple driver systems (401 yA-D and 402 xA-D) and multipole structures (410A-D) may be implemented in separate layers. The deflecting structures 450A-D may be used as deflectors, etc., implemented in the deflecting scanning unit 132 shown in FIG. 2 or the deflectors 309-1 and 309-2 shown in FIG. 3A. Each of a plurality of driver systems (401 yA-D and 402 xA-D) is electrically connected to a set of opposing electrodes implemented in a multipole structure (410A-D) and configured to provide a plurality of discrete output states to the set of opposing electrodes implemented in the multipole structure. For example, driver 401yA may be electrically connected to one set of opposing electrodes implemented in multipole structure 410A, and driver 402xA may be electrically connected to another set of opposing electrodes in multipole structure 410A. The deflecting structures 450A-D and deflecting structure 400 (shown in FIG. 4A) share the same functionality, such as steering the electron beam. Multipole structures 410A-D and multipole structure 410 (shown in FIG. 4A) share the same functionality to deflect an electron beam in a certain direction when provided with an output state from a driver system. The driver systems 401A-D and 402A-D and the

driver systems

401y and 402x (shown in FIG. 4A) share the same functionality to provide discrete output states to the multipole structure to deflect the beam. Further, while FIG. 4B illustrates four layers of deflecting structures 450A-D, it should be understood that the deflecting structures may be implemented in any number of layers.

Although in the embodiment of FIG. 4B, each of the plurality of layers (e.g., 410A-D) is sized to have substantially the same size, the size of each layer may be determined by the physical dimensions (e.g., length, inner diameter, and outer diameter) of the electrodes implemented in that layer and correspond to the deflection angle. For example, deflection structures (e.g., 450A-D) in each layer may deflect the electron beams at substantially the same deflection angle when driver systems 401yA-D and 402xA-D provide substantially the same output state to the electrodes of multipole structures 410A-D. In another example, deflection structures (e.g., 450A-D) in each layer may deflect the electron beam at different deflection angles when its corresponding driver system (e.g., 401yA-D and 402 xA-D) provides different output states to the electrodes of its corresponding multipole structure (e.g., 410A-D).

In some embodiments, one or more of the layers (e.g., the layer comprising the deflection structure 450D) may be implemented with a driver system comprising a linear amplifier with a limited output voltage swing to provide finer deflection control by enabling embodiments to provide high resolution output voltages to electrodes in one layer of the multilayer structure. For example, when a scanning deflection system in an electron beam inspection system is configured to deflect an electron beam with a deflection equivalent to applying 155V to a single conventional multipole structure of the same size as one of 410A-D, a controller may configure a switch connected to the multipole structure (e.g., one of 450A-C) to deliver 50V from a separate power supply implemented in each deflection structure. Thus, the electrode pairs in three of the four multipole structures in FIG. 4B may be connected to-25V and +25V, respectively. To achieve a residual deflection equivalent to 5V applied to a conventional multipole structure of the same size, the controller may configure the deflection structure (e.g., 450D) implemented with the linear amplifier described above to provide-2.5V and 2.5V to the multipole structure. However, since the range of such a linear amplifier is much smaller than that required by existing deflectors, it can be implemented more easily, faster, lower power, etc. than existing deflectors.

Referring now to fig. 4C, fig. 4C illustrates a cross-sectional view of another deflection system 550 that may be used in an electron beam inspection system, in accordance with an embodiment of the present disclosure. Deflection system 550 includes deflection structures 550A-D, where each structure is in a corresponding layer. Each deflection structure 550A-D includes a manipulator or multipole structure (510A-D) connected to a plurality of actuators (501 yA-D and 502 xA-D). In some embodiments, the multiple driver systems (501 yA-D and 502 xA-D) and multipole structures (510A-D) may be implemented in separate layers. The deflecting structures 550A-D may be used as deflectors implemented in the deflecting scanning unit 132 shown in FIG. 2 or as deflectors 309-1 and 309-2 shown in FIG. 3A. Each of the plurality of driver systems (501 yA-D and 502 xA-D) is electrically connected to a set of opposing electrodes implemented within the multipole structure (510A-D) and is configured to provide a plurality of discrete output states to the set of opposing electrodes implemented in the multipole structure. For example, the driver 501yA may be electrically connected to one set of opposing electrodes implemented in the multipole structure 510A, and the driver 502xA may be electrically connected to another set of opposing electrodes in the multipole structure 520A. The deflecting structures 550A-D and deflecting structures 450A-D (shown in FIG. 4B) share the same function, e.g., steering the electron beam. Multipole structures 510A-D and multipole structures 410A-D (shown in FIG. 4B) share the same function to deflect an electron beam in one direction when provided with an output state from a driver system. The driver systems 501yA-D and 502xA-D and the driver systems 401yA-D and 402xA-D (shown in FIG. 4B) share the same functionality to provide discrete output states to the multipole structure to deflect the beam. Further, while FIG. 4C illustrates four layers of deflection structures 550A-D, it should be understood that the deflection structures may be implemented in any number of layers.

In the present embodiment, each of the plurality of layers is set to be different in length, and therefore, when each layer is provided with substantially the same output state, the deflection angle of each layer is different. In some embodiments, the size of each layer may be set to a different proportion of the size of the smallest layer. The first structure may have a size of N and the second structure may have a size of M, where a ratio of N to M satisfies a certain relationship. For example, in the embodiment of FIG. 4C, the lengths of the multipole structures 510A-D are: 510A is N,510B is 2N,510C is 4N, and 510D is 8N. When the driver systems 501A-D and 502A-D provide the same output state to each of the multipole structures 510A-D, the multipole structure 510D generates the highest deflection angle, the multipole structure 510C generates the second high deflection angle, the multipole structure 510B generates the third high deflection angle, and the multipole structure 510A generates the minimum deflection angle because the length (e.g., 8N) of 510D along the Z-axis direction (e.g., along the primary optical axis 100_1 shown in fig. 2) is the longest. When the driver system provides the same output state to all multipole structures, the deflection angle is proportional to the length of the multipole structure. Furthermore, while fig. 4C shows that the size of the layers increases in the direction of travel of the beam through the deflector (e.g., along the primary optical axis 100 \, 1), it should be understood that different arrangements of the size of the layers may be implemented in the deflection system.

In some embodiments, one or more of the layers (e.g., the layer comprising deflection structure 550A) may be implemented with a driver system that includes a linear amplifier with a limited output voltage swing to provide finer deflection control. That is, such layers may be configured to provide a variable range of outputs, rather than being limited to discrete output states. This may enable embodiments to provide a high resolution output voltage to the electrodes in one layer of the multilayer structure. For example, when a scanning deflection system in an electron beam inspection system is configured to deflect an electron beam with a deflection equivalent to applying 155V to a single conventional multipole structure of the same size as 510A, the controller may configure switches connected to the multipole structure (e.g., 510B) to deliver-37.5V and +37.5V from separate power supplies electrically connected thereto. To achieve deflection equivalent to the remainder of a conventional multipole structure of the same size as 510A, the controller may configure the deflection structure implemented with the linear amplifier described above (e.g., deflection structure 550A) and apply-2.5V and +2.5V to the multipole structure.

In some embodiments, only one layer of the multilayer structure may be provided with a linear amplifier and configured to provide an output swing. This one layer may be the smallest layer in the multilayer structure. One layer configured to provide an output swing may constitute an optimal control level for deflecting the charged particle beam.

Referring now to fig. 4D, fig. 4D shows a plan view of an illustrative embodiment of a deflection structure 600 that may be implemented in an electron beam inspection system, in accordance with embodiments of the present disclosure. As shown in fig. 4D, the deflection structure 600 includes a multipole structure 610, a first driver system 601y, and a second driver system 602x. The multipole structure 610 includes a first and second set of opposing electrodes 611A-B and 6102A-B, which may be configured to deflect an electron beam in each deflection direction (e.g., y-direction or x-direction) based on an output state applied to each set. The deflection structure 600 of FIG. 4D is similar to the deflection structure 400 of FIG. 4A, except that the diameters of the electrodes 611A-D may be different. Furthermore, the diameter of the electrodes in different layers may be different. For example, as shown in fig. 4E, the inner and outer diameters of the electrodes in the multipole structure 610A may be reduced relative to the inner and outer diameters of the other electrodes.

Further, in some embodiments, the diameter of the electrodes in the same layer may vary. For example, as shown in FIGS. 4F and 4G, electrodes 712A-B may be different than electrodes 711A-B.

Referring now to fig. 6, fig. 6 is a flow chart illustrating an exemplary method 800 of controlling a plurality of driver systems to dynamically deflect an electron beam in accordance with an embodiment of the present disclosure. The method 800 may be performed by an e-beam tool (e.g., the e-beam tool 100 of fig. 2). In particular, a controller of an e-beam tool (e.g., controller 50 of fig. 2) may perform method 800.

In step 810, a first driver system (e.g., driver system 401yA of fig. 4B) in a first deflection structure (e.g., first deflection structure 450A of fig. 4B) can provide a first set of discrete output states to a first set of opposing electrodes of a deflection scan cell (e.g., deflection scan cell 132 of fig. 2) to affect an electron beam. Affecting the beam may involve directing the beam or deflecting the beam. In some embodiments, the first driver system is electrically connected to the first set of opposing electrodes and is configured to provide a plurality of discrete output states to the first set of opposing electrodes.

In some embodiments, the output states may include-100V, 0V, and +100V. In other embodiments, the output states may include-100V, -50V, 0V, +50V, and +100V. It should be understood that different combinations of discrete output states may be provided by the driver system.

In step 820, a second driver system in the first deflection structure (e.g., driver system 402xA of fig. 4B) may provide a second set of discrete output states to a second set of opposing electrodes of the deflection scan cell to affect (e.g., direct) the electron beam. In some embodiments, the second driver system is electrically connected to the second set of opposing electrodes and is configured to provide a plurality of discrete output states to the second set of opposing electrodes.

In some embodiments, such as embodiments in which the deflection system (e.g., deflection system 450 of fig. 4B) includes another layer having a second deflection structure (e.g., deflection structure 450B of fig. 4B), steps 830 and 840 may be further performed. In step 830, a third driver system in the second deflection structure (e.g., driver system 401yB of fig. 4B) may provide a third set of discrete output states to a third set of opposing electrodes of the deflection scan unit to affect (e.g., direct) the electron beam. In some embodiments, the third driver system is electrically connected to the third set of opposing electrodes and is configured to provide a plurality of discrete output states to the third set of opposing electrodes.

In step 840, a fourth driver system in the second deflection structure (e.g., driver system 402xB of fig. 4B) may provide a fourth set of discrete output states to a fourth set of opposing electrodes of the deflection scan unit to affect (e.g., direct) the electron beam. In some embodiments, the fourth driver system is electrically connected to the fourth set of opposing electrodes and is configured to provide a plurality of discrete output states to the fourth set of opposing electrodes. In some embodiments, the second deflecting structure may be placed in a different layer than the first deflecting structure. Further, the set of opposing electrodes can be any type of multipole structure (e.g.,

multipole structure

410A or 410B of fig. 4B), such as a dipole (2-pole) structure, a quadrupole (4-pole) structure, an octupole (8-pole) structure, and the like.

In some embodiments, such as embodiments in which deflection system 450 includes another layer having a third deflection structure (e.g., deflection structure 450C of fig. 4B), step 850 may be further performed. In step 850, the linear driver system in the third deflection system is instructed to control the output state of the other set of electrodes to influence the electron beam. In some embodiments, the linear driver system is electrically connected to the set of electrodes and is configured to provide a continuous output state to the set of electrodes. A linear driver system may be used to deflect the beam in two directions (e.g., in the x-direction and the y-direction).

Referring now to FIG. 7A, FIG. 7A shows an exemplary charged particle beam device 700 (also referred to as device 700), device 700 including charged particle beam deflectors 709-1 and 709-2 (also referred to as primary electron beam deflectors 719-1 and 719-2), according to embodiments of the present disclosure. The apparatus 700 may include a charged particle source, e.g., an electron source configured to emit primary electrons from a cathode 701 and to be extracted using an extractor electrode 702 to form a primary electron beam 700B1 along a primary optical axis 700-1. The apparatus 700 may further comprise an anode 703, a condenser lens 704, a beam limiting aperture array 705, a signal electron detector 706, an objective 707, a scanning deflection unit comprising primary electron beam deflectors 709-1 and 709-2 configured to be controlled by a deflection control unit 720, control electrodes 714 and a sample 715. It should be understood that related components may be added, omitted, or reordered as appropriate. It should also be understood that in the context of the present disclosure, unless otherwise indicated, a charged particle beam device may refer to an electron beam device, a primary charged particle beam may refer to a primary electron beam, and a charged particle beam deflector may refer to an electron beam deflector.

The electron source (not shown) may include a thermionic source configured to emit electrons upon the provision of thermal energy to overcome the work function of the source, a field emission source configured to emit electrons upon exposure to a large electrostatic field, and the like. In the case of a field emission source, the electron source may be electrically connected to a controller (e.g., controller 50 of fig. 2) configured to apply and adjust the voltage signal based on desired landing energy, sample analysis, source characteristics, and the like. The extractor electrode 702 may be configured to extract or accelerate electrons emitted from the field emission gun, e.g., to form a primary electron beam 700B1, the primary electron beam 700B1 forming a virtual or real main beam intersection (not shown) along the main optical axis 700-1. The primary electron beam 700B1 may be visualized as emanating from a primary beam intersection. In some embodiments, the controller 50 may be configured to apply and adjust a voltage signal to the extractor electrode 702 to extract or accelerate electrons generated from the electron source. The magnitude of the voltage signal applied to the extractor electrode 702 may be different from the magnitude of the voltage signal applied to the cathode 701. In some embodiments, the difference between the magnitudes of the voltage signals applied to the extractor electrode 702 and the cathode 701 may be configured to accelerate the downstream electrons along the primary optical axis 700-1 while maintaining the stability of the electron source. As used in the context of the present disclosure, "downstream" refers to a direction from the electron source toward the sample 715 along the path of the primary electron beam 700B1. With respect to the positioning of elements of a charged particle beam device (e.g., device 700 of fig. 7A), "downstream" refers to the position of an element below or behind another element along the path of the primary electron beam from the electron source, and "immediately downstream" refers to the position of a second element below or behind the first element along the path of the primary electron beam 700B1, such that there are no other active elements between the first element and the second element. For example, as shown in fig. 7A, a charged particle beam deflector 709-1 may be positioned downstream of the condenser lens 704, and a signal electron detector 706 may be positioned immediately downstream of the beam limiting aperture array 705, such that no other optical or electron optical elements are present between the beam limiting aperture array 705 and the electron detector 706. As used in the context of the present disclosure, "upstream" may refer to a location of an element above or before another element along the path of the primary electron beam from the electron source, and "immediately upstream" refers to a location of a second element above or before the first element along the path of the primary electron beam 700B1, such that there are no other active elements between the first and second elements. As used herein, an "active element" may refer to any element or component whose presence may modify an electromagnetic field between a first element and a second element by generating an electric, magnetic, or electromagnetic field.

The apparatus 700 may comprise a condenser lens 704, the condenser lens 704 being configured to receive a part or a majority of the primary electron beam 700B1 and to focus the primary electron beam 700B1 on a beam limiting aperture array 705. The condenser lens 70 may be substantially similar to the condenser lens 110 of fig. 2 and may perform substantially similar functions. Although illustrated as a magnetic lens in fig. 7A, the condenser lens 704 may be an electrostatic lens, a magnetic lens, an electromagnetic lens, a compound electromagnetic lens, or the like. The condenser lens 704 may be electrically coupled with the controller 50. Controller 50 may apply an electrical excitation signal to condenser lens 504 to adjust the focusing power of the condenser lens based on factors including, but not limited to, the mode of operation, the application, the desired analysis, the sample material to be inspected, and the like.

Apparatus 700 may further include a beam limiting aperture array 705, beam limiting aperture array 705 configured to limit a beam current of primary electron beam 700B1 passing through one of a plurality of beam limiting apertures of beam limiting aperture array 705. Although only one beam limiting aperture is shown in fig. 7A, beam limiting aperture array 705 may include any number of apertures having uniform or non-uniform aperture sizes, cross-sections, or spacings. In some embodiments, beam limiting aperture array 705 may be disposed downstream of condenser lens 704 or immediately downstream of condenser lens 70 and substantially perpendicular to primary optical axis 700-1. In some embodiments, beam limiting aperture array 705 may be configured as a conductive structure including a plurality of beam limiting apertures. Beam limiting aperture array 705 may be electrically connected to controller 50 via a connector (not shown), and controller 50 may be configured to instruct the provision of voltage to beam limiting aperture array 705. The voltage provided may be a reference voltage, for example, ground potential. The controller 50 may also be configured to maintain or regulate the supplied voltage. The controller 50 may be configured to adjust the position of the beam limiting aperture array 705.

The apparatus 700 may include one or more signal electronic detectors 706. Signal electron detector 706 may be configured to detect substantially all secondary electrons and a portion of the backscattered electrons based on an azimuth of emission, a polar angle of emission, an energy of emission, etc. of the backscattered electrons. In some embodiments, signal electron detector 706 may be configured to detect secondary electrons, backscattered electrons, or auger electrons (auger electrons). Signal electrons emitted from sample 715 having low emission energy (typically ≦ 50 eV) or small emitter angles may comprise secondary electron beam(s) 700B2, while signal electrons having high emission energy (typically >50 eV) and medium emitter angles may comprise backscattered electron beam(s) (not shown). In some embodiments, 700B2 may include secondary electrons with small emitter angles, low-energy backscattered electrons, or high-energy backscattered electrons. It should be appreciated that although not shown, a portion of the backscattered electrons may be detected by signal electron detector 706. In overlay metrology and inspection applications, signal electron detector 606 may be used to detect secondary electrons generated from surface layers and backscattered electrons generated from deeper layers of the underlying layer, such as deep trenches or high aspect ratio holes.

The apparatus 700 may further comprise a compound objective 707, the compound objective 707 being configured to focus the primary electron beam 700B1 on a surface of the sample 715. Objective 707 may also be configured to focus signal electrons, such as secondary electrons having low emission energy or backscattered electrons having high emission energy, on a detection surface of a signal electron detector (e.g., in-lens signal electron detector 706). Objective 707 may be substantially similar to or perform substantially similar functions to objective assembly 131 of fig. 2.

In some embodiments, the objective 707 can include a cavity defined by the space between the

imaginary planes

707A and 707B. It should be understood that

imaginary planes

707A and 707B labeled as dashed lines in fig. 7A are for illustration purposes only. An imaginary plane 707A closer to the condenser lens 704 may define an upper boundary of the chamber, and an imaginary plane 707B closer to the sample 715 may define a lower boundary of the chamber of the objective 707. As used herein, the "cavity" of the objective lens refers to a space defined by elements of the magnetic lens, which are configured to allow the primary electron beam to pass, wherein the space is rotationally symmetric around the primary optical axis. The term "within the objective lens cavity" or "inside the objective lens cavity" refers to the space defined within the

imaginary planes

707A and 707B and the inner surfaces of the magnetic lenses directly exposed to the primary electron beam. The

planes

707A and 707B may be substantially perpendicular to the main optical axis 700-1. Although fig. 7A shows a tapered cavity, the cross-section of the cavity may be cylindrical, tapered, staggered (tapered) cylindrical, staggered tapered, or any suitable cross-section.

The apparatus 700 may further include a scanning deflection unit including primary charged particle beam deflectors (e.g., electron beam deflectors) 709-1 and 709-2, the electron beam deflectors 709-1 and 709-2 configured to deflect the primary electron beam 700B1 and scan the primary electron beam 700B1 over the surface of the sample 715 to form a field of view (FOV). In some embodiments, the scanning deflection unit including the primary electron beam deflectors 709-1 and 709-2 may be referred to as a beam manipulator or beam manipulator assembly. The dynamic deflection of the primary electron beam 700B1 may cause a desired area or desired region of interest of the sample 715 to be scanned, e.g., in a raster scan pattern, to generate SE and BSE for sample inspection. One or more primary electron beam deflectors 709-1 and 709-2 may be configured to deflect the primary electron beam 700B1 in the X-axis or the Y-axis or a combination of the X-axis and the Y-axis. As used herein, the X-axis and Y-axis form cartesian coordinates, and the primary electron beam 700B1 propagates along the Z-axis or primary optical axis 700-1.

Electrons are negatively charged particles and travel through an electron optical column and can do so at high energies and high speeds. One method of deflecting electrons is to pass the electrons through an electric or magnetic field, for example, generated by a pair of plates held at two different potentials, or pass a current through a deflection coil, among other techniques. Varying the electric or magnetic field on a deflector, such as primary electron beam deflector 709-1 or 709-2, may vary the deflection angle of the electrons in the primary electron beam 700B1 based on factors including, but not limited to, electron energy, applied electric field magnitude, deflector dimensions, and the like.

In some embodiments, one or two primary electron beam deflectors 709-1 and 709-2 may be positioned within the cavity of objective lens 707. As shown in fig. 7A, the entirety of the primary electron beam reflectors 709-1 and 709-2 may be positioned within the cavity of the objective lens 707. In some embodiments, the entirety of the at least one primary electron beam deflector may be positioned within the cavity of the objective lens 707. A beam deflector (e.g., primary electron beam deflector 709-1) may be circumferentially disposed along an inner surface of objective lens 707. One or more primary electron beam reflectors may be placed between the signal electron detector 706 and the control electrode 714. In some embodiments, all primary electron beam deflectors may be placed between the signal electron detector 706 and the control electrode 714.

In some embodiments, the primary electron beam deflectors 709-1 and 709-2 may comprise electrostatic deflectors or magnetic deflectors. The electron beam deflector 709-1 may also be referred to as an "upper deflector" and the electron beam deflector 709-2 may be referred to as a "lower deflector". As used herein, "upper" and "lower" denote the relative position of the deflector with respect to the trajectory of the primary electron beam 700B1. As used herein, an upper deflector refers to a deflector that is located upstream and closer to the electron source, and a lower deflector refers to a deflector that is located downstream from the upper deflector and closer to the sample 715. Although fig. 7A shows only two primary electron beam deflectors 709-1 and 709-2, it is to be understood that the charged particle beam device 700 may suitably comprise two or more deflectors.

In some embodiments, each of the upper and lower deflectors 709-1 and 709-2 may comprise a segmented deflector. Fig. 7B illustrates an exemplary structure of a segmented electron beam deflector 709-1 according to an embodiment of the present disclosure. The electron beam deflector 709-1 may include segments 709-1A, 709-1B, and 709-1C coaxially disposed along the primary optical axis 700-1. The segments 709-1A, 709-1B, 709-1C may have substantially similar inner radii or different inner radii relative to the main optical axis 700-1, and the lengths of the segments 709-1A, 709-1B, and 709-1C may be substantially similar or different. As shown, each segment may include a multi-polar structure having eight electrodes 709-1e to 709-8e arranged radially with respect to the primary optical axis 700-1, and may be configured to operate differently based on the voltage applied to each electrode. Multiple electrode pairs may be combined such that deflection in a two-dimensional plane is possible. In some embodiments, each segment (segments 709-1A, 709-1B, and 709-1C) may comprise a multi-polar structure having two electrodes (dipoles), four electrodes (quadrupoles), or eight electrodes (octupoles), or any number of electrodes. Each segment (segments 709-1A, 709-1B, and 709-1C) may include the same number of electrodes or a different number of electrodes. Although fig. 7B shows a deflector structure comprising three segments, and eight electrodes per segment, the deflector may comprise fewer or more segments and fewer or more electrodes. In some embodiments, the number of segments in the upper deflector 709-1 and the lower deflector 709-2 may be different. It should be understood that although fig. 7A illustrates an apparatus 700 that includes two segmented deflectors, two or more segmented deflectors may be suitably used.

In some embodiments, the electrodes 709-1e to 709-8e of the segments 709-1A, 709-1B and 709-1C may be held in place by a support structure (not shown), such as a ring, sleeve, stent, or the like support structure. The support structure may be made of a non-conductive material including, but not limited to, ceramic, glass, and the like.

Referring again to FIG. 7A, sample 715 may be disposed on a plane substantially perpendicular to primary optical axis 700-1. The position of the plane of sample 715 can be adjusted along the main optical axis 700 so that the distance between sample 715 and the pole piece of objective 707 can be adjusted. In some embodiments, the specimen 715 may be electrically connected to the controller 50 via a connector (not shown), and the controller 50 may be configured to provide a voltage to the specimen 715 to move the specimen 715 along the primary optical axis 700-1. The controller 50 may also be configured to maintain or regulate the supplied voltage. It should be appreciated that sample 715 may be placed on a sample support or stage configured to receive a signal from a controller, for example, to adjust the height of the sample along main optical axis 700-1. In some embodiments, movement of sample 715 or sample stage along primary optical axis 700-1 may be controlled using mechanical, electromechanical, or other suitable motion mechanisms.

The apparatus 700 may further comprise a deflection control unit 720 (described with reference to fig. 7C), the deflection control unit 720 being configured to control the operation of the primary electron beam deflectors 709-1 and 709-2. Although the deflection control unit 720 is shown as a separate control unit in fig. 7A, the deflection control unit 720 may be integrated with the controller 50, thereby becoming a part of the controller 50. Deflection control unit 720 may include circuitry and components configured to power one or more components (e.g., amplifiers, digital-to-analog converters, distributed output stages, etc.), generate and provide electrical signals, and other functionality. In some embodiments, deflection control unit 720 may include electronic driver circuitry to individually control the operation of each segment of the electron beam deflector (e.g., primary electron beam deflectors 709-1 and 709-2).

Referring now to fig. 7C, fig. 7C illustrates an exemplary configuration of a deflection control unit 720 associated with segmented charged particle beam deflectors (e.g., primary electron beam deflectors 709-1 and 709-2), according to an embodiment of the present disclosure. As shown, each primary beam deflector may be electronically driven by a respective driver system. For example, the deflection control unit 720 may include a driver system 725-1 associated with the primary beam deflector 709-1, and a driver system 725-2 associated with the primary beam deflector 709-2. Driver system 722-1 can include scan control unit 730, digital-to-analog converter 734-1, variable gain amplifier 740-1, and distributed output stages 751-1, 752-1, and 753-1. It should be understood that although not shown, the driver system 725-1 may include other components and circuitry, such as power supplies, timing circuits, etc., needed to properly manipulate the primary electron beam traveling along the primary optical axis 700-1.

The scan control unit 730 can be configured to generate and provide control signals 751-1a, 752-1a, and 753-1a, with the control signals 751-1a, 752-1a, and 753-1a configured to activate an enable or disable state of the respective distributed output stages. The scan control unit 730 may be further configured to generate a deflection signal 732-1, the deflection signal 732-1 being configured to be applied to one or more segments 709-1A, 709-1B and 709-1C of the primary electron beam deflector 709-1. In some embodiments, deflection control unit 720 may include a single scan control unit 730, with single scan control unit 730 configured to generate and provide control signals and deflection signals for multiple driver systems (e.g., 725-1 and 725-2). Deflection signal 732-1 may comprise a voltage signal applied to one or more segments of the primary electron beam deflector.

In some embodiments, driver system 725-1 may include circuitry such as a digital-to-analog converter 734-1, digital-to-analog converter 734-1 configured to convert digital deflection signals 732-1 to analog deflection signals. The driver system 725-1 may also include circuitry, such as a variable gain amplifier 740-1, the variable gain amplifier 740-1 configured to receive the analog deflection signal and generate a tunable amplitude of the deflection signal. In general, a VGA is a signal conditioning amplifier with an electronically settable voltage gain. Variable gain amplifier 740-1 may comprise analog VGA, digital VGA, or any suitable circuitry. In some embodiments, the driver system 725-1 can also include circuitry such as a distributed output stage implemented as a plurality of directly coupled amplifiers or relays, or other suitable circuitry.

In an exemplary configuration of the deflection control unit 720 as shown in FIG. 7C, the segments 709-1A, 709-1B and 709-1C of the primary electron beam deflector 709-1 may be connected to distributed output stages 751-1, 752-1 and 753-1, respectively. The enabled or disabled state of distributed output stages 751-1, 752-1 and 753-1 may be activated by control signals 751-1a, 752-1a and 753-1a, respectively, provided by scan control unit 730. Variable gain amplifier 740-1 may be configured to output a tunable amplitude of deflection signal 732-1 applied to primary electron beam deflector 709-1 while maintaining a low noise level. In the enable mode, activated by a control signal provided by the scan control unit 730, the distributed output stage (e.g., 751-1, 752-1, or 753-1) may reproduce (reduce) the output signal from the variable gain amplifier 740-1 to drive the corresponding segment of the primary beam deflector 709-1. For example, control signal 751-1A may activate an enabled state of distributed output stage 751-1 such that distributed output stage 741-1 may reproduce an adjusted output signal comprising a tunable amplitude of deflection signal 732-1 from variable gain amplifier 740-1 to be applied to segment 709-1A of primary electron beam deflector 709-1. The primary electron beam may be deflected based on a deflection signal applied to the segment 709-1A of the primary electron beam deflector 709-1. In some embodiments, in a disable mode of a distributed output stage (e.g., 751-1, 752-1, or 753-1), the output signal may be grounded and the distributed output stage may be powered down. Such a configuration may help reduce power consumption as well as provide other advantages. The driver system 725-2 may be substantially similar to the driver system 725-1 and may perform substantially similar functions to control the primary electron beam deflector 709-2. It will be appreciated that the apparatus 700 may comprise two or more primary electron beam deflectors and corresponding driver systems.

Some advantages of a beam deflection system including segmented deflectors (e.g., primary electron beam deflectors 709-1 and 709-2) controlled by a driver system (e.g., driver system 725-1) such as in fig. 7C include, but are not limited to:

i. the effective length or deflection sensitivity of the beam deflector is adjusted by activating or deactivating the segments of the primary electron beam deflector.

Extending the working range of the beam deflector to provide a large range of deflection sensitivity based on the desired FOV and landing energy of the primary electron beam.

The position of the deflection center may be adjusted based on the segments and the number of segments activated to deflect the primary electron beam.

Referring now to fig. 7D, fig. 7D illustrates an exemplary deflection field distribution of the primary electron beam deflectors 709-1 and 709-2 according to an embodiment of the disclosure.

In some embodiments, the primary electron beam deflectors 709-1 and 709-2 may comprise electrostatic deflectors, and deflection voltages applied to the electrodes of the segments (e.g., 709-1e-709-8e of fig. 7B) may generate an electrostatic deflection field experienced by the primary electron beam 700B1 traveling along the primary optical axis 700-1. As shown in FIG. 7D, deflection field distribution patterns 762-1, 762-2, 764-1 and 764-2 represent exemplary distributions of deflection fields experienced by a primary electron beam 700B1 traveling downstream from an electron source to a sample (e.g., sample 715 of FIG. 7A). In some embodiments, the desired deflection sensitivity of the primary electron beam deflector may be based on the landing energy or the desired field of view (FOV) of the primary electron beam. In the context of the present disclosure, "deflection sensitivity" may refer to the displacement or deflection of the primary electron beam from its original path per unit change in the deflection field causing the deflection. As used herein, the landing energy of an electron beam may be defined as the energy at which electrons of the primary electron beam strike the sample. The landing energy of the primary electron beam is equal to the potential difference between the electron emission source and the stage/sample. For example, if the power supply is operated at-10 kV, and the sample is applied at-5 kV, the landing energy of the primary electrons may be 5keV. Typically, in SEM, the landing energy may be between 0.2keV and 50keV, depending on the application, the material under study, the tool conditions, and the like.

In some embodiments, it may be desirable to image the sample with low landing energies (0.2 to 10 keV). At low landing energies, the deflection sensitivity of the primary electron beam deflectors 709-1 and 709-2 may be higher, and therefore, in order to acquire a certain FOV, the required deflection voltage signals from the respective driver systems 725-1 and 725-2 may be lower. Typically, digital-to-analog converters (DACs), such as digital-to-analog converters 734-1 and 734-2, have optimal linearity when the analog output voltage is about 50% -70% of the total voltage output range. For example, if the desired deflection voltage signal is below the optimal linear range of the digital-to-analog converter 734-1, the induced noise level may be high. In this case, a scan control unit (e.g., scan control unit 730 of FIG. 7C) may generate and provide a control signal (e.g., control signal 752-1a of FIG. 7C) to activate only the enabled state of distributed output stage 752-1 such that only segment 709-1B may receive a deflection signal (e.g., deflection signal 732-1 in FIG. 7C) to create deflection field distribution pattern 764-1. The reduced deflection sensitivity due to the reduced effective deflector length may result in an increase in the required deflection voltage signal, which may return the digital-to-analog converter 734-1 and the driver system 725-1 to an optimal linear performance state. Based on the distribution and intensity of the deflection field, electrons of an incident primary electron beam (e.g., primary electron beam 700B1 of fig. 7A) may experience a deflection that deviates from the original trajectory. The segment 709-1B of the primary electron beam deflector 709-1 may deflect the primary electron beam based on a deflection voltage signal between two or more electrodes. The scan control unit 730 may generate and provide a control signal 752-2a to activate an enable state of the distributed output stage 752-2 such that the segment 709-2B may receive a deflection signal to deflect the primary electron beam to create a deflection field distribution pattern 764-2. The scan control unit 730 can also be configured to provide control signals to activate the disable state of the distributed output stages 751-1, 753-1, 751-2, and 753-2, thereby grounding the disabled distributed output stages.

In some embodiments, it may be desirable to image samples with high landing energies (> 10 keV). At high landing energies, the deflection sensitivity of the primary electron beam deflectors 709-1 and 709-2 may be low, and therefore, in order to acquire a certain FOV, the required deflection voltage signals from the respective driver systems 725-1 and 725-2 may be high. The variable gain amplifiers, such as variable gain amplifiers 740-1 and 740-2, may not, by themselves, provide sufficient signal gain as required by the deflector. In this case, the scan control unit 730 may generate and provide control signals 751-1a, 752-1a, and 753-1a to activate the enable states of all corresponding distributed output stages 751-1, 752-1, and 753-1, respectively, such that all segments 709-1a, 709-1B, and 709-1C may receive the deflection signal 732-1 to create a deflection field distribution pattern 762-1, the deflection field distribution pattern 762-1 being wider compared to the deflection field distribution pattern 764-1. A wide deflection field distribution may result in an increase in the effective length of the primary electron beam deflector 709-1, thereby improving deflection sensitivity. The effective length of the deflector can be increased to meet the deflection sensitivity requirements to acquire a larger FOV. The scan control unit 730 may further generate and provide control signals 751-2a, 752-2a and 753-2a to activate the enable states of all corresponding distributed output stages 751-2, 752-2 and 753-2, respectively, such that all segments 709-2a, 709-2B and 709-2C may receive the deflection signal 732-2, thereby creating a deflection field distribution pattern 762-2, the deflection field distribution pattern 762-2 being wider compared to the deflection field distribution pattern 764-2. In this configuration, the deflection field distribution patterns 762-1 and 762-2 are wider along the main optical axis 700-1 as compared to the deflection field distribution patterns 764-1 and 764-2, resulting in higher deflection sensitivity. Although fig. 7D shows a uniform deflection field distribution between the primary electron beam deflectors 709-1 and 709-2, it is to be understood that the deflection field distribution may also be non-uniform. Additionally or alternatively, deflector designs may be adjusted, including number of electrodes, number of segments, segment inner radius, electrode material; voltage gain of the amplifier, etc., to adjust the FOV and deflection sensitivity at the desired landing energy range.

Referring now to fig. 7E, fig. 7E illustrates an exemplary deflection field distribution of the primary electron beam deflectors 709-1 and 709-2 according to an embodiment of the disclosure. In some embodiments, it may be desirable to reduce off-axis aberrations at large FOVs to maintain high image quality. In this case, the scan control unit 730 may be configured to provide control signals to activate the enabled states of the distributed output stages 751-1 and 753-2, such that the segments 709-1A and 709-2C may receive deflection signals and deflect the primary electron beams based on the generated deflection field distribution patterns 766-1 and 766-2. By doing so, the effective deflection length d2 or deflection sensitivity can be increased. In some embodiments, the scan control unit 730 may be configured to provide control signals to activate the enabled states of the distributed output stages 752-1 and 752-2 such that the segments 709-1B and 709-2B may receive the deflection signals and deflect the primary electron beams based on the generated deflection field distribution patterns 768-1 and 768-2. In such a configuration, the effective deflection length d1 may be less than d2, and the overall deflection sensitivity may be lower. It will be appreciated that these are exemplary configurations and that other combinations of activation of different segments of different beam deflectors can also be used to adjust the deflection sensitivity over a wide range of landing energies and FOVs as appropriate.

Referring now to fig. 8A, fig. 8A shows an exemplary configuration of a deflection control unit 820 associated with charged particle beam deflectors (e.g., primary beam deflectors 809-1 and 809-2), according to an embodiment of the present disclosure. The primary electron beam deflectors 809-1 and 809-2 can each include a hybrid deflector that includes an electrostatic deflector (e.g., 809-1E, 809-2E) and a magnetic deflector (e.g., 809-1M, 809-2M). As shown, each primary beam deflector may be electronically driven by a respective driver system. For example, the deflection control unit 820 may include a driver system 825-1 associated with the primary beam deflector 809-1, and a driver system 825-2 associated with the primary beam deflector 809-2. Driver system 825-1 may include scan control unit 830, driver control units 845-1E and 845-1M, and relays 841-1E and 842-1M controlled by control signals 843-1 and 844-1, respectively, generated by scan control unit 830. Driver system 825-2 may include scan control unit 830, driver control units 845-2E and 845-2M, and relays 841-2E and 842-2M that are controlled by control signals 843-2 and 844-2, respectively, generated by scan control unit 820. It should be understood that although not shown, the driver systems 825-1 and 825-2 may include other components and circuitry, such as power supplies, timing circuits, etc., needed to manipulate the primary electron beam traveling along the primary optical axis 800-1. It should be understood that relays (e.g., relays 841-1E, 841-2E, 842-1M, and 842-2M) are merely examples of functional requirements for switching between signal and ground states to activate or deactivate deflectors, respectively. Other suitable electrical switching mechanisms may also be used, such as, but not limited to, electrical switches, distributed output gates.

Hybrid deflectors such as primary beam deflectors 809-1 and 809-2 (including electrostatic and magnetic deflectors) can be used to acquire large FOVs over a large range of landing energies. This is because at low landing energies, the deflection sensitivity of the electrostatic deflector (e.g., 809-1E) can be higher than the deflection sensitivity of the magnetic deflector, while at high landing energies, the deflection sensitivity of the magnetic deflector (e.g., 809-1M) can be higher than the deflection sensitivity of the electrostatic deflector. In addition to the high deflection sensitivity of magnetic deflectors at high landing energies, the scanning speed of magnetic deflectors is also slow. At high landing energies, the signal electrons may include primarily backscattered electrons (BSE) originating from deep layers of the sample. Due to the low BSE yield, the required sampling rate may not be very high, which may allow the magnetic deflector to be used properly at high landing energies.

At low landing energy, the scan control unit 830 may generate a control signal 843-1, the control signal 843-1 configured to activate the relay 841-1E to enable the driver control unit 845-1E. The scan control unit 830 may also be configured to provide deflection signals to the driver control unit 845-1E for application to the electrostatic deflector 809-1E of the primary electron beam deflector 809-1. However, at high landing energies, the scan control unit 830 may generate a control signal 844-1, the control signal 844-1 configured to activate the relay 842-1M to enable the driver control unit 835-1M. Scan control unit 830 may also be configured to provide a deflection signal to driver controller 845-1M for application to magnetic deflector 809-1M. Thus, the electrostatic and magnetic deflectors of the hybrid primary beam deflector 809-1 may be configured to deflect the primary beam to acquire a large FOV over a large range of landing energies, while maintaining a high image quality.

As shown in FIG. 8A, electrostatic deflectors 809-1E and 809-2E are located upstream relative to respective magnetic deflectors 809-1M and 809-2M. In some embodiments, electrostatic deflectors 809-1E and 809-2E and magnetic deflectors 809-1M and 809-2M may be coaxially disposed along primary optical axis 800-1. The inner radii and lengths of the electrostatic deflectors 8029-1E and 8029-2E and the magnetic deflectors 809-1M and 809-2M may be substantially similar or different. In some embodiments, electrostatic deflectors 809-1E and 809-2E can comprise segmented deflectors. In some embodiments, the electrostatic deflectors 809-1E and 809-2E may be located downstream relative to the respective magnetic deflectors 809-1M and 809-2M, or any combination of relative positions is possible.

Referring now to fig. 8B, fig. 8B illustrates an exemplary configuration of the deflection control unit 821 according to an embodiment of the present disclosure. In contrast to the deflection control unit 820 of FIG. 8A, in the primary electron beam deflector 809-1, the electrostatic deflector 809-1E can be substantially coplanar with the magnetic deflector 809-1M, and in the primary electron beam deflector 809-2, the electrostatic deflector 809-2E can be substantially coplanar with the magnetic deflector 809-2M such that the electrostatic and magnetic fields substantially overlap. In such a configuration, the radii of the magnetic deflectors 809-1M and 809-2M can be larger than the radii of the corresponding electrostatic deflectors 809-1E and 809-2E. Such a configuration of the coplanar arrangement of the electrostatic deflector and the magnetic deflector is desirable in design options to reduce the overall length of the electron optical column or to make the electron optical column of the charged particle beam device compact.

Referring now to fig. 8C, fig. 8C shows an exemplary configuration of a deflection control unit 822 according to an embodiment of the present disclosure. The electrostatic deflector 809-1E can be located downstream of the magnetic deflector 809-1M, while the electrostatic deflector 809-2E can be located upstream of the magnetic deflector 809-2M. Like

deflection control units

820 and 821, electrostatic and magnetic deflectors can be activated at different landing energies when they are operated separately. However, with the electrostatic and magnetic deflectors operating in concert, the electrostatic deflectors 809-1E and 809-2E can provide faster scan speeds over small FOVs, while the magnetic deflectors 809-1M and 809-2M can provide static actuation to direct the FOVs scanned by the electrostatic deflectors to different locations within a larger FOV. In some embodiments, magnetic deflectors 809-1M and 809-2M can have smaller scan bandwidths to reduce noise levels and provide slow scan deflection signals. This configuration may reduce the voltage required for the electrostatic deflector because the required FOV may be smaller. This is beneficial when the landing energy of the primary electron beam is high.

In some embodiments, the electrostatic deflector or the magnetic deflector, or both, may be activated based on the landing energy and the desired FOV. For example, in a low landing energy mode, only the electrostatic deflector (e.g., 809-1E or 809-2E) can be activated; in the medium landing energy mode, only the magnetic deflector (e.g., 809-1M or 809-2M) can be activated; in the high landing energy mode, both electrostatic and magnetic deflectors can be activated. With the electrostatic and magnetic deflectors activated simultaneously, the effective deflection length can be longer along the primary optical axis 800-1 when the magnetic deflectors 809-1M and 809-2M are located downstream of the respective electrostatic deflectors 809-1E and 809-2E. Further, in the case where the electrostatic deflectors and magnetic deflectors are activated simultaneously, the deflection field strength is stronger when the electrostatic deflectors 809-1E and 809-2E are coplanar with the respective magnetic deflectors 809-1M and 809-2M.

Referring now to fig. 8D, fig. 8D illustrates an exemplary configuration of a hybrid deflector 810 in accordance with an embodiment of the present disclosure. The hybrid deflector 810 may include an electrostatic deflector formed of an electrostatic electrode 860 and a magnetic deflector formed of a coil 870 wound on a protrusion of the electrostatic electrode 860. In some embodiments, protrusions may be formed on the outer surface of the electrostatic electrode 860, away from the primary optical axis 800-1 (represented as the z-axis extending in the paper), so that the electrostatic electrode 860 may also serve as a pole piece for the magnetic deflector.

Referring now to fig. 9A and 9B, fig. 9A and 9B are schematic diagrams illustrating an exemplary configuration of a charged particle beam device 900 including an adjustable sample stage, according to an embodiment of the present disclosure. The charged particle beam device 900 (also referred to as device 900) may comprise an electron beam device. The apparatus 900 may include a low landing energy primary electron beam 900B1 or a high landing energy primary electron beam 900B3 traveling along a primary optical axis 900-1 toward the sample 915, primary electron beam deflectors 909-1 and 909-2, an objective lens assembly 907, and a control electrode 914. In contrast to apparatus 700, the position of sample 915 of apparatus 900 is adjustable along the main optical axis 900-1. The position of sample 915 may be adjusted along primary optical axis 900-1 relative to other components, including control electrode 914, objective lens 907, etc. The sample 915 may be disposed on a plane 915P substantially perpendicular to the main optical axis 900-1.

Fig. 9A shows a first position along a plane 915P in which a sample 915 is disposed, defining a distance WD1 between the sample 915 and a pole of the objective 907. An exemplary deflection path of the low landing energy primary electron beam 900B1 on the sample 916 is also shown. In some embodiments, the position of the plane 915P along which the sample 915 is disposed can be dynamically adjusted, for example, based on feedback associated with detection efficiency, detection distribution, imaging resolution, desired analysis, and the like. In some embodiments, sample 915 may be disposed on a sample stage (not shown) or a sample holder (not shown). In this configuration, the position of the sample stage or sample holder may be adjusted so that the position of the sample 915 may be adjusted. Although not shown, it is understood that the position of the sample 915 or sample stage/rack can be adjusted using electromechanical devices, including but not limited to piezoelectric motors, actuators, micromanipulators, and the like. Other micro-motion mechanisms may also be used, including but not limited to mechanical mechanisms, electromechanical mechanisms.

One of several methods of maintaining a large FOV over a large landing energy range may include increasing the working distance WD1 between the sample 915 and the pole piece (polepece) of the objective 907. The working distance may be adjusted by, for example, lowering the sample 915 or lowering the stage holding the sample. The low landing energy primary electron beam 900B1 may be focused on the surface of the sample 915 by the objective lens 907, and the deflectors 909-1 and 909-2 may scan the beam 900B1 over the sample 915 to form a FOV. It should be appreciated that the low landing energy primary electron beam 900B1 may be offset a greater distance from the main optical axis 900-1 due to the higher deflection sensitivity of the electrostatic primary electron beam deflector 909-1, as shown in FIG. 9A.

Fig. 9B shows a second position along the plane 915P along which the sample 915 is disposed, defining a second working distance WD2 between the polarity of the sample 915 and the objective 907. The second working distance WD2 may be greater than the first working distance WD1 such that the sample 915 is away from the polarity of the objective lens 908 along the primary optical axis 900-1. As shown in FIG. 9B, since the deflection sensitivity of the electrostatic deflectors 909-1 and 909-2 can be low, the high landing energy primary electron beam 900B3 can be deflected a smaller distance than the low landing energy primary electron beam 900B 1. An increase in the vertical distance between the samples 915 may allow the high landing energy primary electron beam 900B3 to travel a longer distance before being incident on the samples 915, so that a larger FOV may be acquired. In some embodiments, lowering the position of the plane 915P along which the sample 915 is disposed may increase the objective lens focal length and reduce the magnetic lens excitation required to focus the primary electron beam 900B3 on the sample 915 to avoid magnetic saturation on the objective lens pole pieces.

Referring now to fig. 10, fig. 10 is a flow chart representing an exemplary method 1000 for deflecting a primary charged particle beam passing through a deflection scanning unit of a charged particle beam device (e.g., device 700) according to an embodiment of the present disclosure. The steps of method 1000 may be performed by apparatus 700 of fig. 7A, for example, to perform or otherwise use features of a computing device (e.g., controller 50 of fig. 1) for illustrative purposes. It should be understood that the illustrated method 1000 may be altered to modify the order of steps and include additional steps.

In step 1010, a first charged particle beam deflector (e.g., primary electron beam deflector 709-1 of fig. 7A) may deflect a primary electron beam (e.g., primary electron beam 700B1 of fig. 7A). The primary electron beam deflector may comprise an electrostatic deflector, a magnetic deflector, or a hybrid deflector comprising an electrostatic deflector and a magnetic deflector. The first electrostatic deflector may comprise a segmented deflector comprising a multipole structure having two or more electrodes.

In step 1020, a second primary electron beam deflector (e.g., primary electron beam deflector 709-2 of fig. 7A) may deflect the primary electron beam. The second primary electron beam deflector may comprise an electrostatic deflector, a magnetic deflector, or a hybrid deflector comprising an electrostatic deflector and a magnetic deflector. The second primary electron beam deflector may be located downstream of the first primary electron beam deflector. The second electrostatic deflector can comprise a segmented deflector having a plurality of segments (e.g., segments 709-1A, 709-1B, and 709-1C of fig. 7B) coaxially disposed along the main optical axis 700-1, each segment comprising a multi-polar structure having two or more electrodes.

In step 1030, a controller having circuitry (e.g., deflection control unit 720 of fig. 7A or 7C) may individually control operation of each of the plurality of segments of the first and second primary electron beam deflectors. The controller may include a driver system associated with the first primary electron beam deflector (e.g., the first driver system 725-1 of fig. 7C) and a second driver system associated with the second primary electron beam deflector (e.g., the second driver system 725-2 of fig. 7B). The first driver system or the second driver system may include a scan control unit (e.g., scan control unit 730 of FIG. 7C) configured to generate and provide control signals (e.g., 751-1a, 752-1a, and 753-1a of FIG. 7C). The control signal may activate an enable or disable state of the corresponding distributed output stage. The scan control unit may also be configured to generate a deflection signal (e.g., deflection signal 732-1 of fig. 7C) configured to be applied to one or more segments of the primary electron beam deflector.

The driver system may further comprise circuitry for converting the digital deflection signals to analog deflection signals. The driver system may also include circuitry configured to receive the analog deflection signals from a DAC (digital-to-analog converter) and generate tunable amplitudes of the deflection signals. The driver system may also include circuitry configured to function as a switching mechanism, or a distributed output stage implemented as a directly coupled amplifier or relay, or other suitable circuitry.

In an exemplary configuration of the deflection control unit, the segments of the primary electron beam deflector can be connected to distributed output stages (e.g., distributed output stages 751-1, 752-1, and 753-1 of FIG. 7C). The enable or disable state of the distributed output stages may be activated by a control signal provided by the scan control unit. The variable gain amplifier (e.g., variable gain amplifier 740-1 of fig. 7C) may be configured to output a tunable amplitude of the deflection signal applied to the primary electron beam deflector while maintaining a low noise level. In an enable mode, activated by a control signal provided by the scan control unit, the distributed output stage may reproduce the output signal from the variable gain amplifier to drive the respective segment of the primary electron beam deflector. For example, control signal 751-1a may activate an enabled state of distributed output stage 751-1 such that distributed output stage 741-1 may reproduce an adjusted output signal comprising a tunable amplitude of deflection signal 732-1 from variable gain amplifier 740-1 to be applied to segment 709-1a of primary beam deflector 709-1. The primary electron beam may be deflected based on a deflection signal applied to a segment of the primary electron beam deflector.

Referring now to fig. 11, fig. 11 is a flow chart representing an exemplary method 1100 for deflecting a primary charged particle beam passing through a deflection scanning unit of a charged particle beam device (e.g., device 700), in accordance with an embodiment of the present disclosure. The steps of method 1100 may be performed by apparatus 700 of fig. 7A, for example, to perform or otherwise use features of a computing device (e.g., controller 50 of fig. 1) for illustrative purposes. It should be understood that the illustrated method 1100 may be altered to modify the order of steps and include additional steps.

In step 1110, a first charged particle beam deflector (e.g., primary beam deflector 809-1 of fig. 8A) may deflect the primary electron beam. The primary electron beam deflector may comprise a hybrid deflector having electrostatic and magnetic deflectors.

In step 1120, a second primary electron beam deflector (e.g., primary electron beam deflector 809-2 of FIG. 8A) may deflect the primary electron beam. The second primary electron beam deflector may comprise a hybrid deflector having electrostatic and magnetic deflectors. The second primary electron beam deflector may be located downstream of the first primary electron beam deflector. The first hybrid deflector and the second hybrid deflector may be disposed along the main optical axis 800-1.

In step 1130, a first driver system (e.g., driver system 825-1 of fig. 8A) may be associated with a first primary electron beam deflector (e.g., primary electron beam deflector 809-1) and a driver system (e.g., driver system 825-2 of fig. 8B) may be associated with a second primary electron beam deflector. The first and second driver systems may individually control the electrostatic and magnetic deflectors of the first and second primary electron beam deflectors. The driver system may include a scan control unit (e.g., scan control unit 830 of FIG. 8A), a driver control unit (e.g., driver control units 845-1E and 845-1M of FIG. 8A), and relays (e.g., relays 841-1E and 842-1M of FIG. 8A) controlled by control signals (e.g., control signals 843-1 and 844-1) generated by the scan control unit.

Hybrid deflectors such as primary electron beam deflectors including electrostatic deflectors and magnetic deflectors can be used to acquire large FOVs over a large range of landing energies. This is because at low landing energies, the deflection sensitivity of the electrostatic deflector (e.g., 809-1E) can be higher than the deflection sensitivity of the magnetic deflector, and at high landing energies, the deflection sensitivity of the magnetic deflector (e.g., 809-1M) can be higher than the deflection sensitivity of the electrostatic deflector.

In some embodiments, the controller may control the charged particle beam system. The controller may comprise a computer processor. The controller may instruct components of the charged particle beam system to perform various functions, such as controlling various drivers for manipulating one or more electron beams. The controller may include memory as a storage medium, such as a hard disk, cloud storage, random Access Memory (RAM), other types of computer readable memory, and the like. The controller may be in communication with the cloud storage device. A non-transitory computer readable medium may be provided that stores instructions for the processor of the controller 50 to dynamically deflect the electron beam or perform other functions and methods consistent with the present disclosure. Common forms of non-transitory media include, for example, a floppy disk, a flexible disk, a hard disk, a solid state drive, a magnetic tape, or any other magnetic data storage medium. In some embodiments, the storage medium may comprise a CD-ROM, any other optical data storage medium, any physical medium with patterns of holes, a RAM, a PROM, and EPROM, a FLASH-EPROM, or any other FLASH memory, NVRAM, cache, registers, any other memory chip or cartridge, and networked versions thereof.

The embodiments may be further described using the following clauses:

1. an apparatus, comprising:

a first charged particle beam manipulator positioned at the first layer and configured to affect a charged particle beam; and

a second charged particle beam manipulator positioned at a second layer and configured to affect the charged particle beam, wherein the first charged particle beam manipulator and the second charged particle beam manipulator each comprise:

a plurality of electrodes having a first set of opposing electrodes and a second set of opposing electrodes;

a first driver system electrically connected to the first set of opposing electrodes and configured to provide a plurality of first discrete output states to the first set of opposing electrodes; and

a second driver system electrically connected to the second set of opposing electrodes and configured to provide a plurality of second discrete output states to the second set of opposing electrodes.

2. The apparatus of clause 1, wherein the first driver system is configured to enable the first set of opposing electrodes to deflect the charged particle beam in a first direction.

3. The apparatus of clause 2, wherein the second driver system is configured to enable the second set of opposing electrodes to deflect the charged particle beam in a second direction perpendicular to the first direction.

4. The apparatus of clause 1, wherein the first driver system is configured to provide discrete output states to the first set of opposing electrodes to deflect the charged particle beam in a first direction.

5. The apparatus of clause 4, wherein the second driver system is configured to provide discrete output states to the second set of opposing electrodes to deflect the charged particle beam in a second direction substantially perpendicular to the first direction.

6. The apparatus of clause 1, wherein the first charged particle beam manipulator is configured to deflect the charged particle beam at a first angle and the second charged particle beam manipulator is configured to deflect the charged particle beam at a second angle.

7. The apparatus of any of clauses 1-6, wherein each of the first and second driver systems comprises a switch for providing the plurality of first discrete output states and the plurality of second discrete output states.

8. The apparatus of any of clauses 1-6, wherein each of the first and second driver systems comprises a plurality of power supplies, each of the plurality of power supplies providing a discrete output state.

9. The apparatus of any of clauses 1-6, wherein the first driver system comprises a first power supply configured to provide the first plurality of discrete output states, and the second driver system comprises a second power supply configured to provide the second plurality of discrete output states.

10. The apparatus according to clause 1, wherein the first charged particle beam manipulator and the second charged particle beam manipulator are of equal size.

11. The apparatus according to clause 1, wherein the first charged particle beam manipulator has a size N and the second charged particle beam manipulator has a size M, wherein M is an integer multiple of N.

12. The apparatus of clause 11, wherein N defines a length of the first charged particle beam manipulator and M defines a length of the second charged particle beam manipulator.

13. The apparatus of clause 1, further comprising:

a third charged particle beam manipulator configured to influence the charged particle beam, the third charged particle beam manipulator comprising:

a plurality of electrodes;

a driver system electrically connected to the plurality of electrodes and configured to provide a continuous output state to the plurality of electrodes.

14. The apparatus of clause 1, wherein the first layer comprises a plurality of charged particle beam manipulators.

15. The apparatus of clause 1, further comprising a controller for generating various control signals to control the first and second driver systems.

16. The apparatus of clause 1, wherein a charged particle beam manipulator of the first charged particle beam manipulator and the second charged particle beam manipulator comprises a set of electrodes formed in a substrate.

17. A method for influencing a charged particle beam passing through a deflection scanning unit, the method comprising:

providing, by a first driver system, a first set of discrete output states to a first set of opposing electrodes of a first manipulator of the deflection scanning unit; and

providing, by a second driver system, a second set of discrete output states to a second set of opposing electrodes of the first manipulator of the deflected scanning unit.

18. The method of clause 17, further comprising:

providing, by a third driver system, a third set of discrete output states to a third set of opposing electrodes of a second manipulator of the deflection scanning unit; and

providing, by a fourth driver system, a fourth set of discrete output states to a fourth set of opposing electrodes of the second manipulator of the deflection scanning unit,

wherein providing the third and fourth sets of discrete output states enables the second manipulator to affect the charged particle beam passing through the deflection scanning unit.

19. The method of any of clauses 17 and 18, further comprising:

controlling a linear drive system to affect the charged particle beam, wherein the linear drive system controls a state of an electrode set of a third manipulator, the third manipulator being positioned at a third layer.

20. A non-transitory computer-readable medium comprising a set of instructions executable by one or more processors of a controller to cause the controller to perform a method for deflecting a charged particle beam to scan a sample, the method comprising:

instructing a first driver system connected to a first set of opposing electrodes to control a first set of discrete output states to cause the first set of opposing electrodes of a first manipulator to affect a charged particle beam; and

instructing a second driver system connected to a second set of opposing electrodes to control a second set of discrete output states to cause the second set of opposing electrodes of the first manipulator to affect the charged particle beam,

wherein the first driver system, the first set of opposing electrodes, the second driver system, and the second set of opposing electrodes are implemented in a first layer.

21. The computer-readable medium of clause 20, wherein the set of instructions is executable by the one or more processors of the controller to cause the controller to further perform:

instructing a third driver system connected to a third set of opposing electrodes to control a third set of discrete output states to cause the third set of opposing electrodes of a second manipulator to affect the charged particle beam; and

instructing a fourth driver system connected to a fourth set of opposing electrodes to control a fourth set of discrete output states to cause the fourth set of opposing electrodes of the second manipulator to affect the charged particle beam,

wherein the third driver system, the third set of counter electrodes, the fourth driver system and the fourth set of counter electrodes are implemented in a second layer.

22. The computer-readable medium of any of clauses 20 and 21, wherein the set of instructions is executable by the one or more processors of the controller to cause the controller to further perform:

instructing a linear driver system connected to a set of electrodes to control an output state to affect the charged particle beam, wherein the linear driver system and the electrodes are implemented in another layer.

23. A deflector structure comprising:

a plurality of electrode stages, each of the stages comprising an electrode set configured to surround a charged particle beam of a scanning charged particle microscope and pass the charged particle beam substantially through a center of the electrode set of each of the stages,

wherein each electrode of the set is configured to be driven by a driver providing a plurality of discrete output states.

24. The deflector structure of clause 23, wherein a first one of the stages has a different size or shape than a second one of the stages.

25. The deflector structure of clause 23, wherein the plurality of discrete output states comprises a first voltage and a second voltage.

26. The deflector structure of clause 23, wherein the deflector structure is formed as a microelectromechanical system.

27. The apparatus of clause 1, wherein the charged particle beam comprises an electron beam.

28. The deflector structure of clause 23, wherein each stage is sized to be a different proportion of the size of the smallest of the stages.

29. The deflector structure of clause 23, wherein the driver comprises a power source.

30. The deflector structure of clause 23, wherein the driver comprises a plurality of drivers.

31. The apparatus of clause 1, wherein the second tier is below the first tier.

32. The apparatus of clause 1, wherein the plurality of first discrete output states and the plurality of second discrete output states are the same set of discrete output states.

33. The apparatus of clause 6, wherein the first charged particle beam manipulator has a first length so as to deflect the charged particle beam at the first angle and the second charged particle beam manipulator has a second length so as to deflect the charged particle beam at the second angle.

34. The apparatus of clause 6, wherein a first output is applied to the first charged particle beam manipulator so as to deflect the charged particle beam at the first angle, and a second output is applied to the second charged particle beam manipulator so as to deflect the charged particle beam at the second angle.

35. The apparatus of clause 7, wherein the first driver system includes a first set of switches configured to provide the first plurality of discrete output states, and the second driver system includes a second set of switches configured to provide the second plurality of discrete output states.

36. The apparatus of clause 8, wherein the first driver system includes a first set of power supplies configured to provide the first plurality of discrete output states, and the second driver system includes a second set of power supplies configured to provide the second plurality of discrete output states.

37. A charged particle beam device, comprising:

a first charged particle beam deflector configured to influence a primary charged particle beam generated by a charged particle source along a main optical axis;

a second charged particle beam deflector positioned downstream of the first charged particle beam deflector and configured to affect the primary charged particle beam, wherein the first charged particle beam deflector and the second charged particle beam deflector each comprise a plurality of segments; and

a controller having circuitry configured to individually control operation of each of the plurality of segments.

38. The apparatus of clause 37, wherein one of the plurality of segments of the first and second charged particle beam deflectors comprises a multipole structure configured to deflect the primary charged particle beam, and wherein the multipole structure comprises a dipole, quadrupole or octopole structure.

39. The apparatus of clause 38, wherein the segment comprises a plurality of electrodes arranged radially with respect to the primary optical axis.

40. The apparatus according to any of clauses 37 to 39, wherein the plurality of segments of the first and second charged particle beam deflectors are co-axially positioned along the primary optical axis.

41. The apparatus according to any of clauses 37 to 40, wherein the first charged particle beam deflector and the second charged particle beam deflector are located substantially within the cavity of the objective lens and along the primary optical axis.

42. The apparatus of any of clauses 37-41, wherein the controller comprises circuitry further configured to:

generating a first electrical signal configured to control an output stage associated with a segment of the plurality of segments; and

generating a second electrical signal configured to be applied to the segment to cause deflection of the primary charged particle beam.

43. The apparatus of clause 42, wherein the controller comprises circuitry further configured to adjust the second electrical signal based on a desired degree of deflection of the primary charged particle beam.

44. The apparatus of clause 43, wherein the controller comprises circuitry further configured to:

applying the first electrical signal to the output stage associated with the segment of the plurality of segments; and

applying a conditioned second electrical signal to the segment based on the first electrical signal, wherein the first electrical signal comprises an activation signal or a deactivation signal configured to enable or disable the output stage, respectively.

45. The apparatus according to clause 44, wherein the output stage enabled in response to an activation signal is configured to activate a corresponding segment, the activation of the corresponding segment comprising application of the conditioned second electrical signal to cause the primary charged particle beam to be deflected.

46. The apparatus of clause 44, wherein the output stage disabled in response to a disable signal is configured to disable the corresponding segment such that the primary charged particle beam passes substantially undeflected.

47. The apparatus of any of clauses 42 to 46, wherein the controller comprises circuitry further configured to generate the first electrical signal based on a landing energy of the primary charged particle beam.

48. The apparatus according to any of clauses 42 to 47, wherein the controller comprises circuitry further configured to generate the first electrical signal based on desired deflection sensitivities of the first and second charged particle beam deflectors.

49. The apparatus of any of clauses 42-48, wherein the controller comprises circuitry further configured to modify a characteristic of the second electrical signal, and wherein modification of the characteristic of the second electrical signal comprises digital-to-analog signal conversion.

50. The apparatus of any of clauses 37 to 49, wherein the primary charged particle beam comprises an electron beam.

51. The apparatus according to any of clauses 37 to 50, wherein the first charged particle beam deflector and the second charged particle beam deflector comprise electrostatic deflectors.

52. The apparatus of clause 47, wherein the position of the plane of the sample is adjustable along the primary optical axis to adjust the working distance between the sample and the pole piece based on the landing energy of the primary charged particle beam and the desired field of view.

53. A charged particle beam device, comprising:

a second charged particle beam deflector positioned downstream of the first charged particle beam deflector and configured to affect the primary charged particle beam, wherein the first charged particle beam deflector and the second charged particle beam deflector each comprise:

an electrostatic deflector electrically connected to a first driver system configured to enable the electrostatic deflector to deflect the primary charged particle beam; and

a magnetic deflector electrically connected to a second driver system configured to enable the magnetic deflector to deflect the primary charged particle beam.

54. The apparatus of clause 53, wherein the magnetic deflector is located downstream of the electrostatic deflector along the primary optical axis in the first and second charged particle beam deflectors.

55. The apparatus of any of clauses 53 and 54, wherein the first driver system comprises a first relay configured to:

receiving a first electrical signal from a signal source; and

switching between a grounded state and an activated state of the first deflection driver unit based on the first electrical signal, wherein

In the active state, the first deflection driver unit is configured to activate the electrostatic deflector to deflect the primary charged particle beam based on a second electrical signal, and wherein

In the grounded state, the first deflection driver unit is configured to deactivate the electrostatic deflector.

56. The apparatus of clause 55, wherein the second driver system comprises a second relay configured to:

receiving a third electrical signal from the signal source; and

switching between a grounded state and an activated state of a second deflection driver unit based on the third electrical signal, wherein

In the active state, the second deflection driver unit is configured to activate the magnetic deflector to cause the primary charged particle beam based on a fourth electrical signal, and wherein

In the grounded state, the second deflection driver unit is configured to deactivate the magnetic deflector.

57. The apparatus according to any of clauses 53 to 56, wherein the first deflection driver unit and the second deflection driver unit are configured to activate the electrostatic deflector or the magnetic deflector, respectively, based on a landing energy of the primary charged particle beam.

58. The apparatus of clause 53, wherein the electrostatic deflector and the magnetic deflector are substantially coplanar with respect to the primary optical axis.

59. The apparatus of clause 53, wherein the electrostatic deflector of the first charged particle beam deflector is located downstream of the magnetic deflector of the first charged particle beam deflector, and wherein the electrostatic deflector of the second charged particle beam deflector is located upstream of the magnetic deflector of the second charged particle beam deflector.

60. The apparatus of any of clauses 57-59, wherein a position of a plane of a sample is adjustable along the primary optical axis to adjust a working distance between the sample and a pole piece based on the landing energy of the primary charged particle beam and a desired field of view.

61. A method for deflecting a primary charged particle beam passing through a deflection scanning unit of a charged particle beam device, the method comprising:

deflecting said primary charged particle beam generated by a charged particle source along a main optical axis using a first charged particle beam deflector;

deflecting the primary charged particle beam using a second charged particle beam deflector positioned downstream of the first charged particle beam deflector, wherein the first charged particle beam deflector and the second charged particle beam deflector each comprise a plurality of segments; and

individually controlling operation of each of the plurality of segments using a controller having circuitry.

62. The method of clause 61, further comprising generating, using the controller:

a first electrical signal configured to control an output stage associated with a segment of the plurality of segments; and

a second electrical signal configured to activate the segment to deflect the primary charged particle beam.

63. The method of clause 62, further comprising adjusting, using the controller, the second electrical signal based on a desired degree of deflection of the primary charged particle beam.

64. The method of clause 63, further comprising, with the controller:

65. The method of clause 64, further comprising: enabling the output stage in response to the activation signal to activate the corresponding segment, thereby causing the primary charged particle beam to be deflected.

66. The method of clause 64, further comprising: disabling the output stage in response to the disable signal to disable the corresponding segment such that the primary charged particle beam passes undeflected.

67. The method of any of clauses 62 to 66, further comprising generating, using the controller, the first electrical signal based on a landing energy of the primary charged particle beam

68. The method of clause 67, further comprising adjusting a position of a plane of a sample along the primary optical axis to adjust a working distance between the sample and a pole piece based on the landing energy of the primary charged particle beam.

69. The method according to any of clauses 62 to 68, further comprising generating, using the controller, the first electrical signal based on desired deflection sensitivities of the first and second charged particle beam deflectors.

70. A method for deflecting a primary charged particle beam passing through a deflection scanning unit of a charged particle beam device, the method comprising:

deflecting the primary charged particle beam using a second charged particle beam deflector positioned downstream of the first charged particle beam deflector, wherein the first charged particle beam deflector and the second charged particle beam deflector each comprise:

an electrostatic deflector electrically connected to a first driver system configured to enable the electrostatic deflector to affect the primary charged particle beam; and

a magnetic deflector electrically connected to a second driver system configured to enable the magnetic deflector to affect the primary charged particle beam.

71. The method of clause 70, further comprising:

generating a first electrical signal and a second electrical signal from a signal source;

receiving the first electrical signal through a first relay; and

In the active state, the first deflection driver unit is configured to activate the electrostatic deflector to deflect the primary charged particle beam based on the second electrical signal, and wherein

72. The method of clause 71, further comprising:

generating a third electrical signal and a fourth electrical signal from the signal source;

receiving the third electrical signal through a second relay; and

In the active state, the second deflection driver unit is configured to activate the magnetic deflector to deflect the primary charged particle beam based on the fourth electrical signal, and wherein

73. The method according to any of clauses 70-72, further comprising activating an electrostatic deflector or a magnetic deflector of the first and second charged particle beam deflectors based on the landing energy of the primary charged particle beam.

74. The method of clause 73, further comprising adjusting a position of a plane of a sample along the primary optical axis to adjust a working distance between the sample and a pole piece based on the landing energy of the primary charged particle beam.

75. A non-transitory computer readable medium storing a set of instructions executable by one or more processors of a charged particle beam device to cause the charged particle beam device to perform a method of deflecting a primary charged particle beam passing through a deflection scanning unit of the charged particle beam device, the method comprising:

individually controlling operation of each segment of the plurality of segments, the each segment configured to deflect the primary charged particle beam.

76. A non-transitory computer readable medium storing a set of instructions executable by one or more processors of a charged particle beam device to cause the charged particle beam device to perform a method of deflecting a primary charged particle beam passing through a deflection scanning unit of the charged particle beam device, the method comprising:

As used herein, unless otherwise specifically noted, the term "or" includes all possible combinations unless not feasible. For example, if a stated component may include a or B, the component may include a, B, or a and B and C, unless explicitly stated otherwise or not possible. As a second example, if a claimed component can include a, B, or C, the component can include a, or B, or C, or a and B, or a and C, or B and C, or a and B and C, unless explicitly stated otherwise or not possible.

While embodiments of the present disclosure have been described in conjunction with various embodiments, it will be understood that various modifications and changes may be made without departing from the scope thereof. It is intended that the specification and examples be considered as exemplary only.

Claims

1. An apparatus, comprising:

a first charged particle beam manipulator positioned at the first layer and configured to affect the charged particle beam; and

2. The apparatus of claim 1, wherein the first driver system is configured to enable the first set of opposing electrodes to deflect the charged particle beam in a first direction.

3. The apparatus of claim 2, wherein the second driver system is configured to enable the second set of opposing electrodes to deflect the charged particle beam in a second direction perpendicular to the first direction.

4. The apparatus of claim 1, wherein the first driver system is configured to provide discrete output states to the first set of opposing electrodes to deflect the charged particle beam in a first direction.

5. The apparatus of claim 4, wherein the second driver system is configured to provide discrete output states to the second set of opposing electrodes to deflect the charged particle beam in a second direction substantially perpendicular to the first direction.

6. The apparatus of claim 1, wherein said first charged particle beam manipulator is configured to deflect said charged particle beam at a first angle and said second charged particle beam manipulator is configured to deflect said charged particle beam at a second angle.

7. The apparatus of claim 1, wherein each of the first and second driver systems comprises a switch to provide the plurality of first discrete output states and the plurality of second discrete output states.

8. The apparatus of claim 1, wherein each of the first and second driver systems comprises a plurality of power supplies, each of the plurality of power supplies providing a discrete output state.

9. The apparatus of claim 1, wherein the first driver system comprises a first power supply configured to provide the plurality of first discrete output states, and the second driver system comprises a second power supply configured to provide the plurality of second discrete output states.

10. The apparatus according to claim 1, wherein the first charged particle beam manipulator and the second charged particle beam manipulator are of equal size.

11. The apparatus according to claim 1, wherein the first charged particle beam manipulator has a size N and the second charged particle beam manipulator has a size M, wherein M is an integer multiple of N.

12. The apparatus of claim 11, wherein N defines a length of said first charged particle beam manipulator and M defines a length of said second charged particle beam manipulator.

13. The apparatus of claim 1, further comprising:

a plurality of electrodes;

14. The apparatus of claim 1, wherein the first layer comprises a plurality of charged particle beam manipulators.

15. A method for influencing a charged particle beam passing through a deflecting scanning unit, the method comprising:

providing, by a second driver system, a second set of discrete output states to a second set of opposing electrodes of the first manipulator of the deflection scanning unit.