阅读说明：本技术 具有单束模式的多束检查设备 (Multi-beam inspection apparatus having single-beam mode ) 是由 任伟明 刘学东 胡学让 陈仲玮 于 2020-03-17 设计创作，主要内容包括：公开了一种支持多种操作模式的多束检查设备。支持多种操作模式的用于检查样品的带电粒子束设备包括被配置为沿着主光轴发射带电粒子束的带电粒子束源、在第一位置与第二位置之间能够移动的可移动孔板、以及控制器,控制器具有电路系统并且被配置为改变该设备的配置以在第一模式与第二模式之间进行切换。在第一模式下,可移动孔板位于第一位置并且被配置为允许源自带电粒子束的第一带电粒子束波穿过。在第二模式下,可移动孔板位于第二位置并且被配置为允许第一带电粒子束波和第二带电粒子束波穿过。(A multi-beam inspection apparatus supporting a plurality of operation modes is disclosed. A charged particle beam device for inspecting a sample supporting multiple modes of operation includes a charged particle beam source configured to emit a charged particle beam along a primary optical axis, a movable aperture plate movable between a first position and a second position, and a controller having circuitry and configured to change a configuration of the device to switch between the first mode and the second mode. In a first mode, the movable aperture plate is in a first position and is configured to allow a first charged particle beam wave originating from the charged particle beam to pass through. In a second mode, the movable aperture plate is in a second position and is configured to allow the first and second charged particle beam waves to pass through.)

1. A charged particle beam apparatus for inspecting a sample supporting multiple modes of operation, comprising:

a charged particle beam source configured to emit a charged particle beam along a primary optical axis;

a first aperture plate configured to form a plurality of charged particle beam waves from the charged particle beam;

a second orifice plate movable between a first position and a second position; and

a controller having circuitry and configured to change a configuration of the device to switch between a first mode and a second mode, wherein:

in the first mode:

the second aperture plate is located at the first position, and the first aperture plate and the second aperture plate are configured to allow a first charged particle beam wave of the plurality of charged particle beam waves to pass through, and

in the second mode:

the second orifice plate being located at the second position, an

The first and second aperture plates are configured to allow the first and second charged particle beam waves of the plurality of charged particle beam waves to pass through.

2. The apparatus of claim 1, wherein the first mode is a single beam mode and the second mode is a multiple beam mode.

3. The apparatus of claim 1, wherein the first charged particle beam is an on-axis beam with respect to the primary optical axis and the second charged particle beam is an off-axis beam with respect to the primary optical axis.

4. The apparatus of claim 1, wherein the second orifice plate is configured to: blocking the second charged particle beam wave when the apparatus is operating in the first mode.

5. The apparatus according to claim 1, wherein the first aperture plate is located between the charged particle beam source and the second aperture plate when the apparatus is operated in the first mode.

6. The apparatus of claim 1, further comprising:

a condenser lens configured to alter a path of the plurality of charged particle beam waves to form a plurality of images of the charged particle beam source on an image plane.

7. The apparatus of claim 6, wherein the second aperture plate is positioned between the first aperture plate and the condenser lens when the apparatus is operating in the first mode.

8. The apparatus of claim 6, wherein the condenser lens is positioned between the first aperture plate and the second aperture plate when the apparatus is operating in the first mode.

9. The apparatus of claim 6, wherein the condenser lens comprises a first deflector and a second deflector, and wherein the second aperture plate is located between the first deflector and the second deflector when the apparatus is operated in the first mode.

10. The apparatus according to claim 1, wherein the second aperture plate is located between the charged particle beam source and the first aperture plate when the apparatus is operated in the first mode.

11. The apparatus of claim 1, further comprising:

a beam splitter configured to deflect secondary electrons generated from the sample; and

first electron detection means configured to detect the secondary electrons when the apparatus is operating in the first mode or the second mode.

12. The apparatus of claim 11, wherein the controller comprises circuitry to:

in the first mode or the second mode, controlling the beam splitter to deflect the secondary electrons towards the first electron detection device, wherein the first electron detection device is aligned with a first secondary optical axis.

13. The apparatus of claim 1, further comprising:

a beam splitter configured to deflect secondary electrons generated from the sample;

first electron detection means configured to detect the secondary electrons when the apparatus is operating in the second mode; and

second electron detection means configured to detect the secondary electrons when the apparatus is operating in the first mode.

14. The apparatus of claim 13, wherein the controller comprises circuitry to:

in the second mode, controlling the beam splitter to deflect the secondary electrons towards the first electron detection device, wherein the first electron detection device is aligned with a first auxiliary optical axis, and

in the first mode, the beam splitter is disabled to allow the secondary electrons to travel toward the second electron detection device.

15. A method of inspecting a sample using a charged particle beam device comprising a first aperture plate configured to form a plurality of charged particle beam waves from a charged particle beam emitted by a charged particle beam source, the method comprising:

moving the second orifice plate from the second position to the first position, wherein:

positioning the second aperture plate in the first position such that a single charged particle beam wave of the charged particle beam can pass through a combination of the first aperture plate and the second aperture plate, and

positioning the second aperture plate in the second position enables a plurality of charged particle beam waves of the charged particle beam to pass through a combination of the first aperture plate and the second aperture plate.

Technical Field

Embodiments provided herein relate generally to a multi-beam inspection apparatus, and more particularly, to a multi-beam inspection apparatus supporting multiple operation modes.

Background

In manufacturing semiconductor Integrated Circuit (IC) chips, pattern defects or foreign substances (residues) inevitably occur on a wafer or a mask during the manufacturing process, thereby reducing the yield. For example, for patterns with smaller critical feature sizes (which have been adopted to meet the more advanced performance requirements of IC chips), undesirable particles can be troublesome.

Pattern inspection tools with charged particle beams have been used to detect defects or undesirable particles. These tools typically employ a Scanning Electron Microscope (SEM). In SEM, a primary electron beam having a relatively high energy is decelerated so as to land on a sample at a relatively low landing energy and focused to form a probe spot thereon. Due to this focused detection point of the primary electrons, secondary electrons will be generated from the surface. The secondary electrons may include backscattered electrons, secondary electrons, or Auger electrons resulting from the interaction of the primary electrons with the sample. The pattern inspection tool may acquire an image of the sample surface by scanning a probe point on the sample surface and collecting secondary electrons.

Disclosure of Invention

Embodiments provided herein disclose a multi-beam inspection apparatus, and more particularly, a multi-beam inspection apparatus supporting multiple operating modes.

In some embodiments, a charged particle beam apparatus for inspecting a sample supports multiple modes of operation. The charged particle beam device comprises a charged particle beam source configured to emit a charged particle beam along a main optical axis, a first aperture plate configured to form a plurality of charged particle beam waves from the charged particle beam, and a second aperture plate movable between a first position and a second position. The charged particle beam device further comprises a controller having circuitry and configured to change a configuration of the device to switch between the first mode and the second mode. When the apparatus is operated in a first mode, the second aperture plate is located at a first position, and the first aperture plate and the second aperture plate are configured to allow a first charged particle beam wave of the plurality of charged particle beam waves to pass through. When the apparatus is operated in a second mode, the second aperture plate is located at a second position, and the first aperture plate and the second aperture plate are configured to allow the first charged particle beam wave and the second charged particle beam wave of the plurality of charged particles to pass through.

In some embodiments, a method is disclosed for inspecting a sample using a charged particle beam device. The charged particle beam device may comprise a first aperture plate configured to form a plurality of charged particle beam waves from a charged particle beam emitted by a charged particle beam source. The method includes moving the second aperture plate from a second position to a first position, wherein positioning the second aperture plate in the first position enables a single charged particle beam wave of the charged particle beam to pass through the combination of the first aperture plate and the second aperture plate, and positioning the second aperture plate in the second position enables a plurality of charged particle beam waves of the charged particle beam to pass through the combination of the first aperture plate and the second aperture plate.

In some embodiments, a charged particle beam device for inspecting a sample supporting multiple modes of operation includes a charged particle beam source configured to emit a charged particle beam along a primary optical axis, a movable aperture plate movable between a first position and a second position, and a controller having circuitry and configured to change a configuration of the device to switch between the first mode and the second mode. When the apparatus is operated in a first mode, the movable aperture plate is in a first position and is configured to allow a first charged particle beam wave of a plurality of charged particle beam waves derived from the charged particle beam to pass through. When the apparatus is operated in a second mode, the movable aperture plate is located at a second position and is configured to allow the first and second charged particle beam waves of the plurality of charged particle beam waves to pass through.

In some embodiments, the charged particle beam apparatus further comprises a plurality of electron detection devices. In some embodiments, the first electron detection device is configured to detect secondary electrons emerging from the sample in the first mode, and the second electron detection device and/or the third electron detection device is configured to detect secondary electrons in the second mode.

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

Drawings

The above and other aspects of the present disclosure will become more apparent by describing exemplary embodiments in conjunction with the attached drawings.

FIG. 1 is a schematic diagram illustrating an exemplary charged particle beam inspection system consistent with embodiments of the present disclosure.

Fig. 2 is a schematic diagram illustrating an exemplary multi-beam apparatus as part of the exemplary charged particle beam inspection system of fig. 1, consistent with an embodiment of the present disclosure.

Fig. 3A and 3B are schematic diagrams of a multi-beam e-beam tool illustrating an exemplary configuration of a movable aperture plate consistent with embodiments of the present disclosure.

Fig. 3C is a schematic diagram of an embodiment of the movable orifice plate of fig. 3A and 3B consistent with embodiments of the present disclosure.

Fig. 4A and 4B are schematic diagrams of a multi-beam e-beam tool illustrating an exemplary configuration of a movable aperture plate consistent with embodiments of the present disclosure.

Fig. 5A and 5B are schematic diagrams of a multi-beam e-beam tool illustrating an exemplary configuration of a movable aperture plate consistent with embodiments of the present disclosure.

Fig. 6A and 6B are schematic diagrams of a multi-beam e-beam tool illustrating an exemplary configuration of a movable aperture plate consistent with embodiments of the present disclosure.

Fig. 6C is a schematic diagram of an embodiment of the movable orifice plate of fig. 6A and 6B consistent with embodiments of the present disclosure.

Fig. 7A and 7B are schematic diagrams of a multi-beam electron beam tool illustrating an exemplary configuration of a secondary electron detection apparatus consistent with an embodiment of the present disclosure.

Fig. 8A and 8B are schematic diagrams of a multi-beam electron beam tool illustrating an exemplary configuration of a secondary electron detection apparatus consistent with an embodiment of the present disclosure.

Fig. 9A, 9B, and 9C are schematic diagrams of a multi-beam electron beam tool illustrating an exemplary configuration of a secondary electron detection apparatus consistent with an embodiment of the present disclosure.

Fig. 10A and 10B are schematic diagrams of a multi-beam electron beam tool illustrating an exemplary configuration of a secondary electron detection apparatus consistent with an embodiment of the present disclosure.

Fig. 10C, 10D, and 10E are schematic diagrams of an embodiment of the secondary electron detection device of fig. 10B consistent with an embodiment of the present disclosure.

Fig. 11 is a flow chart illustrating an exemplary method of inspecting a specimen using a multi-beam e-beam tool consistent with embodiments of the present disclosure.

Detailed Description

Reference will now be made in detail to exemplary embodiments, examples of which are illustrated in the accompanying drawings. The following description refers to the accompanying drawings, in which like reference numerals refer to the same or similar elements in different drawings unless otherwise specified. The implementations set forth in the following description of exemplary embodiments do not represent all implementations consistent with the invention. Rather, they are merely examples of apparatus and methods consistent with aspects related to the invention as set forth in the claims below.

Electronic devices are made up of circuits formed on a silicon wafer 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 been significantly reduced so that more circuits can be mounted on the substrate. For example, an IC chip in a smartphone may be as small as the thumb, but may include more than 20 hundred million transistors, each of which is less than 1/1000 for 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 unusable. Therefore, one goal of the fabrication process is to avoid such defects to maximize the number of functional ICs fabricated in the process, i.e., to improve the overall yield of the process.

One component that improves yield is monitoring the chip fabrication process to ensure that it produces a sufficient number of functional integrated circuits. One method for monitoring the 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). SEM can be used to image these very small structures, in effect taking a "photograph" of the structure. This image can be used to determine whether the structure was formed correctly and whether it was formed in the correct location. If the structure is defective, the process can be adjusted so that the defect is less likely to reoccur.

The SEM scans the surface of the sample with a focused beam of primary electrons. The primary electrons interact with the sample and generate secondary electrons. The SEM creates an image of the scanned area of the sample by scanning the sample with a focused beam and capturing secondary electrons with a detector.

For high throughput inspection, some inspection systems use multiple focused beams of primary electrons. Because multiple focused beams can scan different portions of a wafer simultaneously, multi-beam inspection systems can inspect wafers at higher speeds than single-beam inspection systems. However, the conventional multi-beam inspection system has low detection accuracy and low resolution due to crosstalk between adjacent electron beams. Thus, once a defect on a specimen is detected, conventional multi-beam inspection systems often require that the specimen be transferred to a high resolution single-beam inspection tool for more careful inspection of the detected defect. Even though some newer multi-beam inspection systems provide dual mode support (e.g., multi-beam mode and single-beam mode), the maximum resolution during single-beam mode operation is still lower than what can be achieved using conventional single-beam inspection tools.

One of the main sources of limited resolution during single beam mode operation is the presence of off-axis electron beams that are not used when the multi-beam inspection system is operated in single beam mode. Since the electron source (e.g., electron gun) generates as many electrons as will be generated in the multi-beam mode, the adverse effect between electrons in the single-beam mode is as high as in the multi-beam mode, even though the off-axis electron beam is eventually filtered downstream. For example, source conversion unit 220 in fig. 2 may condition beam 712 and 713 in fig. 7A so that they are blocked from falling on the sample by detector 746 or an aperture (not shown) in fig. 7B. One aspect of the present disclosure includes an adaptive control mechanism for electron beam generation that can eliminate unused off-axis electron beams near the electron beam source before they affect the on-axis electron beam when the tool is operating in single beam mode, and thereby reduce degradation of the single beam.

The relative dimensions of the components in the figures may be exaggerated for clarity. In the following description of the drawings, the same or similar reference numerals refer to the same or similar components or entities, and only the differences with respect to the respective embodiments are described. As used herein, unless otherwise specifically stated, the term "or" encompasses all possible combinations, unless otherwise not feasible. For example, if a component is stated to include a or B, the component may include a or B, or both a and B, unless explicitly stated otherwise or otherwise not possible. As a second example, if it is stated that a 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.

Referring now to fig. 1, fig. 1 is a schematic diagram illustrating an exemplary charged particle beam inspection system 100 consistent with an embodiment of the present disclosure. As shown in fig. 1, a charged particle beam inspection system 100 includes a main chamber 10, a load lock chamber 20, an electron beam tool 40, and an Equipment Front End Module (EFEM) 30. An electron beam tool 40 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 EFEM 30 includes a first load port 30a and a second load port 30 b. The EFEM 30 may include additional load port(s). For example, the first and second load ports 30a and 30b may receive a wafer Front Opening Unified Pod (FOUP), which 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 EFEM 30 transfer wafers to the load lock chamber 20.

The load lock chamber 20 may be connected to a load lock vacuum pump system (not shown) that removes gas molecules in the load lock chamber 20 to achieve a first pressure below atmospheric pressure. After the first pressure is reached, one or more robotic arms (not shown) transfer wafers from the load lock chamber 20 to the main chamber 10. The main chamber 10 is connected to a main chamber vacuum pumping system (not shown) which will remove 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 subjected to inspection by the electron beam tool 40. In some embodiments, the e-beam tool 40 may comprise a single beam inspection tool. In other embodiments, e-beam tool 40 may comprise a multi-beam inspection tool.

The controller 50 is electrically connected to the electron beam tool 40. The controller 50 may be a computer configured to perform various controls of the charged particle beam inspection system 100. The controller 50 may also include processing circuitry configured to perform various signal and image processing functions. Although 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 EFEM 30, it should be 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 aspects of the present disclosure are not limited in their broadest sense to a chamber housing an electron beam inspection tool. Rather, it should be understood that the foregoing principles may also be applied to other tools operating at a second pressure.

Referring now to fig. 2, fig. 2 is a schematic diagram illustrating an exemplary electron beam tool 40 including a multi-beam inspection tool that is part of the exemplary charged particle beam inspection system 100 of fig. 1, consistent with an embodiment of the present disclosure. The multi-beam electron tool 40 (also referred to herein as apparatus 40) comprises an electron source 201, a gun-aperture plate 271, a beam pre-shaping aperture array 272, a condenser lens 210, a source conversion unit 220, a primary projection system 230, a motorized stage 209, and a specimen holder 207, the specimen holder 207 being supported by the motorized stage 209 to hold a specimen 208 (e.g., a wafer or a photomask) to be inspected. The multi-beam electron beam tool 40 may further comprise a secondary projection system 250 and an electron detection device 240. The primary projection system 230 may include an objective lens 231. The beam splitter 233 and the deflection scanning unit 232 may be located inside the primary projection system 230. The electronic detection device 240 may include a plurality of detection elements 241, 242, and 243.

The electron source 201, the gun aperture plate 271, the beam pre-forming aperture array 272, the condenser lens 210, the source conversion unit 220, the beam splitter 233, the deflection scanning unit 232 and the primary projection system 230 may be aligned with the main optical axis 204 of the apparatus 40. The secondary projection system 250 and the electronic detection device 240 may be aligned with the secondary optical axis 251 of the apparatus 40.

The electron source 201 may comprise a cathode (not shown) and an extractor or anode (not shown), wherein during operation the electron source 201 is configured to emit primary electrons from the cathode and the primary electrons are extracted or accelerated by the extractor and/or the anode to form a primary electron beam 202, the primary electron beam 202 forming a primary beam crossover (virtual or real) 203. The primary electron beam 202 may be visualized as being emitted from a primary beam crossover 203.

The source conversion unit 220 may include an image forming element array (not shown), an aberration compensator array (not shown), a beam limiting aperture array (not shown), and a pre-curved micro-deflector array (not shown). In some embodiments, the front curved micro-deflector array deflects the plurality of primary beam waves 211, 212, 213 of the primary electron beam 202 to normally enter the beam limiting aperture array, the image forming element array, and the aberration compensator array. In some embodiments, the condenser lens 210 is designed to focus the primary electron beam 202 into a parallel beam and make it incident perpendicularly on the source conversion unit 220. The array of image forming elements may comprise a plurality of micro-deflectors or micro-lenses to influence the plurality of primary beam waves 211, 212, 213 of the primary electron beam 202 and to form a plurality of parallel images (virtual or real) of the primary beam crossings 203, one for each of the primary beam waves 211, 212 and 213. In some embodiments, the aberration compensator array may include a field curvature compensator array (not shown) and a dispersion compensator array (not shown). The field curvature compensator array may include a plurality of microlenses to compensate for field curvature aberrations of the primary beam 211, 212, and 213. The astigmatism compensator array may include a plurality of micro-diffusers to compensate for astigmatic aberrations of the primary beam 211, 212, and 213. The beam limiting aperture array may be configured to limit the diameter of the individual primary beam waves 211, 212, and 213. By way of example, fig. 2 shows three primary beams 211, 212, and 213, and it is understood that source conversion unit 220 may be configured to form any number of primary beams. The controller 50 may be connected to various portions of the charged particle beam inspection system 100 of FIG. 1. In some embodiments, the controller 50 may perform various image and signal processing functions, as explained in further detail below. The controller 50 may also generate various control signals to manage the operation of the charged particle beam inspection system.

The condenser lens 210 is configured to focus the primary electron beam 202. The condenser lens 210 may also be configured to adjust the current of the primary beam 211, 212, and 213 downstream of the source conversion unit 220 by changing the focusing power of the condenser lens 210. Alternatively, the current may be varied by varying the radial size of the beam-limiting apertures within the array of beam-limiting apertures corresponding to the individual primary beam waves. The current can be varied by varying the radial size of the beam-limiting aperture and the focusing power of the condenser lens 210. The condenser lens 210 may be an adjustable condenser lens, which may be configured such that the position of its first main plane is movable. The adjustable condenser lens may be configured to be magnetic, which may result in off-axis beam waves 212 and 213 illuminating the source conversion unit 220 at an angle of rotation. The angle of rotation varies with the focusing power or the position of the first main plane of the adjustable condenser lens. Accordingly, the condenser lens 210 may be an anti-rotation condenser lens, which may be configured to maintain a rotation angle constant when a focusing power of the condenser lens 210 is changed. In some embodiments, the condenser lens 210 may be an adjustable anti-rotation condenser lens, wherein the angle of rotation of the adjustable anti-rotation condenser lens does not change when the focusing power of the adjustable anti-rotation condenser lens and the position of its first principal plane change.

Objective 231 may be configured to focus beam waves 211, 212, and 213 onto sample 208 for inspection, and in the current embodiment, three probe points 221, 222, and 223 may be formed on the surface of sample 208. The deflection scanning unit 232 is in operation configured to deflect the primary beam waves 211, 212 and 213 to scan the probe points 221, 222 and 223 over individual scan areas in a portion of the surface of the sample 208. The aperture plate 271 is configured in operation to block peripheral electrons of the primary electron beam 202 to reduce coulomb effects. The coulomb effect may enlarge the size of each of the probe points 221, 222, and 223 of the primary beam waves 211, 212, 213, and thus reduce the inspection resolution. In some embodiments, the beam pre-forming aperture array 272 further slices the peripheral electrons of the primary electron beam 202 to reduce coulombic effects. The primary electron beam 202 may be tailored into three beam waves 211, 212, and 213 by a beam pre-shaping aperture array 272.

In response to the incidence of the primary beam waves 211, 212, and 213 or probe points 221, 222, and 223 on the sample 208, electrons emerge from the sample 208 and generate three secondary electron beams 261, 262, and 263. Each of the secondary electron beams 261, 262, and 263 typically includes secondary electrons (electron energy ≦ 50eV) and backscattered electrons (electron energy between 50eV and the landing energy of the primary beam waves 211, 212, and 213).

The beam splitter 233 may be a wien filter including an electrostatic deflector generating an electrostatic dipole field and a magnetic lens (not shown) generating a magnetic dipole field. In operation, beam splitter 233 can be configured to generate an electrostatic dipole field using an electrostatic deflector to apply electrostatic forces to individual electrons of primary beam waves 211, 212, and 213. Beam splitter 233 can also be configured to generate a magnetic dipole field to apply a magnetic force to the electrons. The electrostatic force is equal in magnitude but opposite in direction to the magnetic force. Primary beam waves 211, 212, and 213 can thus pass at least substantially linearly through beam splitter 233 at an at least substantially zero deflection angle.

However, the secondary electron beams 261, 262 and 263 may be deflected towards the secondary projection system 250, and the secondary projection system 250 subsequently focuses the secondary electron beams 261, 262 and 263 onto the detection elements 241, 242 and 243 of the electron detection device 240. The detection elements 241, 242 and 243 are arranged to detect the corresponding secondary electron beams 261, 262 and 263 and generate corresponding signals, which are sent to the controller 50 or a signal processing system (not shown), for example to construct an image of the corresponding scanned area of the sample 208.

In some embodiments, detection elements 241, 242, and 243 detect corresponding secondary electron beams 261, 262, and 263, respectively, and generate corresponding intensity signal outputs (not shown) to an image processing system (e.g., controller 50). In some embodiments, each detection element 241, 242, and 243 may include one or more pixels. The intensity signal output of the detection element may be the sum of the signals generated by all pixels within the detection element.

In some embodiments, the controller 50 may include an image processing system including an image acquirer (not shown) and a storage device (not shown). The image acquirer may include one or more processors. For example, the image capturer may include a computer, server, mainframe, terminal, personal computer, any kind of mobile computing device, etc., or a combination thereof. The image acquirer can be communicatively coupled to the electronic detection device 240 of the apparatus 40 through a medium such as electrical conductors, fiber optic cable, portable storage media, IR, Bluetooth, the internet, wireless networks, radio, or combinations thereof. In some embodiments, the image acquirer may receive the signal from the electronic detection device 240 and may construct the image. The image acquirer can thus acquire an image of the sample 208. The image acquirer may also perform various post-processing functions, such as generating contours, superimposing indicators on the acquired image, and so forth. The image acquirer may be configured to perform adjustment of brightness, contrast, and the like on the acquired image. In some embodiments, the storage device may be a storage medium such as a hard disk, flash drive, cloud storage, Random Access Memory (RAM), other types of computer-readable memory, and so forth. A storage device may be coupled to the image acquirer and may be used to save the scanned raw image data as a raw image and save the post-processed image.

In some embodiments, the image acquirer may acquire one or more images of the sample based on the imaging signals received from the electronic detection device 240. The imaging signal may correspond to a scanning operation for performing charged particle imaging. The acquired image may be a single image including a plurality of imaging regions. The individual images may be stored in a storage device. The single image may be an original image, and the original image may be divided into a plurality of regions. Each of the regions may include one imaged region containing a feature of the sample 208. The acquired images may include multiple images of a single imaging region of the sample 208 sampled multiple times over a time series. The plurality of images may be stored in a storage device. In some embodiments, controller 50 may be configured to perform image processing steps on multiple images of the same location of sample 208.

In some embodiments, the controller 50 may include measurement circuitry (e.g., an analog-to-digital converter) to acquire the distribution of the detected secondary electrons. The electron distribution data collected during the inspection time window in combination with the corresponding scan path data for each of the primary beam waves 211, 212, and 213 incident on the wafer surface can be used to reconstruct an image of the wafer structure being inspected. The reconstructed image may be used to reveal various features of the internal or external structure of the sample 208 and thus may be used to reveal any defects that may be present in the wafer.

In some embodiments, controller 50 may control motorized stage 209 to move sample 208 during inspection of sample 208. In some embodiments, controller 50 may enable motorized stage 209 to continuously move sample 208 in one direction at a constant speed. In other embodiments, controller 50 may enable motorized stage 209 to vary the speed of movement of sample 208 over time according to the steps of the scanning process. In some embodiments, the controller 50 may adjust the configuration of the primary projection system 230 or the secondary projection system 250 based on the image of the secondary electron beams 261, 262, and 263.

Although fig. 2 illustrates the e-beam tool 40 using three primary electron beams, it should be understood that the e-beam tool 40 may use two or more primary electron beams. The present disclosure does not limit the number of primary electron beams used in apparatus 40.

In some embodiments, a multi-beam apparatus may provide a mechanism for supporting single beam mode operation. For example, the multi-beam apparatus may control a deflector array (e.g., the deflector array in the source conversion unit 220 of fig. 2) to adjust deflection angles of a plurality of primary beam waves (e.g., the beam waves 211, 212, and 213 of fig. 2) such that only one of the plurality of primary beam waves will reach a surface of a sample (e.g., the sample 208 of fig. 2). An example of a multi-beam apparatus that supports single mode operation can be found in U.S. patent No. 9,691,586, which is incorporated herein by reference in its entirety. To acquire higher resolution images of the sample using single beam mode, it may be desirable to further reduce the coulomb effect. In some embodiments, if a single beam mode multi-beam apparatus may have as good resolution as a conventional single beam apparatus, the multi-beam apparatus may first perform multi-beam inspection, which typically provides higher throughput than conventional single beam apparatus, and then perform high resolution inspection of defects of interest using the single beam mode. This may eliminate the need for a conventional single beam inspection tool for the second step. Furthermore, this may also improve the overall yield of the inspection process, since the high-throughput inspection step and the high-resolution inspection step may be performed in one tool, which may reduce the time to transfer the sample from the first tool to the second tool.

Referring now to fig. 3A and 3B, fig. 3A and 3B are schematic diagrams of a multi-beam e-beam tool 300 illustrating an exemplary configuration of a movable orifice plate 373 consistent with an embodiment of the present disclosure. The multi-beam e-beam tool 300 may be part of a multi-beam apparatus (e.g. the multi-beam apparatus 40 of fig. 2).

As previously described with respect to fig. 2, the multi-beam electron beam tool 300 may include an electron source 301, a gun aperture plate 371, a beam pre-shaping aperture array 372, and a condenser lens 310. The electron source 301 is configured to emit primary electrons and form a primary electron beam 302. The gun aperture plate 371 is configured to block peripheral electrons of the primary electron beam 302 to reduce coulomb effects, which may reduce inspection resolution. In some embodiments, beam pre-shaping aperture array 372 further slices the peripheral electrons of primary electron beam 302 to reduce coulombic effects. The primary electron beam 302 may be trimmed into three primary electron beam waves 311, 312, and 313 (or any other number of beam waves) after passing through the beam wave pre-forming aperture array 372. The electron source 301, gun aperture plate 371, beam pre-forming aperture array 372, and condenser lens 310 may be aligned with the primary optical axis 304 of the multi-beam electron tool 300.

In some embodiments, the multi-beam electron tool 300 may further comprise a movable aperture plate 373, the movable aperture plate 373 may be used to support multiple operating modes of the electron beam tool 300, such as a single beam mode and a multi-beam mode.

In single beam mode, as shown in fig. 3A, the movable aperture plate 373 may be moved to a first position between the beam pre-shaping aperture array 372 and the condenser lens 310. When the movable orifice plate 373 is placed in the first position, the orifice of the movable orifice plate 373 may be aligned with the main optical axis 304. The movable orifice 373 may be configured to block off-axis beam waves (e.g., beam waves 312 and 313) and allow only on-axis beam waves (e.g., beam wave 311) to pass through during the single beam mode. In some embodiments, the movable orifice plate 373 may include multiple orifices having various sizes (as shown in fig. 3C). In such embodiments, different sized apertures may be selected during the single beam mode depending on the desired current level of the beam. For example, larger apertures may be used when a high current electron beam is required.

In the multi-beam mode, as shown in fig. 3B, the movable orifice 373 may be moved to a second position where the movable orifice 373 is far enough from the path of the primary electron beam waves 311, 312, and 313 that the primary electron beam waves 311, 312, and 313 will pass through.

Referring now to fig. 3C, fig. 3C is a schematic diagram of an embodiment of the movable orifice plate 373 of fig. 3A and 3B, consistent with an embodiment of the present disclosure. In some embodiments, the movable well plate 373 may include one or more wells. In some embodiments, the movable orifice plate 373 may include multiple orifices having different sizes to vary the current of the primary electron beam wave when the electron beam tool is operated in the single beam mode. Although fig. 3C shows a rectangular movable orifice plate, it is understood that the movable orifice plate 373 may be a different shape. For example, the movable orifice plate 373 may be a circular plate having a plurality of orifices. The present disclosure does not limit the shape of the movable orifice 373.

Referring now to fig. 4A and 4B, fig. 4A and 4B are schematic diagrams of multi-beam e-beam tools 400A and 400B illustrating an exemplary configuration of a movable aperture plate consistent with embodiments of the present disclosure. The multi-beam e-beam tools 400A and 400B may be part of a multi-beam apparatus (e.g., the multi-beam apparatus 40 of fig. 2).

Similar to the configuration shown in fig. 3A and 3B, the multi-beam electron beam tools 400A and 400B may include an electron source 401, a gun aperture plate 471, a beam pre-forming aperture array 472, a condenser lens 410, and a movable aperture plate (e.g., 473A and 473B). However, fig. 4A and 4B show embodiments of a multi-beam electron beam tool with a movable aperture plate of a different configuration. Fig. 4A and 4B show that the movable aperture plate can be moved to different positions for single beam mode with respect to other structures aligned with the primary optical axis 404, such as the gun aperture plate 471, the beam pre-shaping aperture array 472, and the condenser lens 410.

For example, the movable aperture plate 473a of fig. 4A may be positioned above the beam pre-forming aperture array 472 and below the gun aperture plate 471 to enable single beam mode operation. In such embodiments, the movable aperture plate 473a may trim off-axis portions of the primary electron beam 402 to generate a single beam wave, such as the electron beam wave 411, after the beam wave pre-shaping aperture array 472.

On the other hand, the movable aperture plate 473B of fig. 4B may be located below the condenser lens 410 to enable single beam mode operation by blocking all off-axis beam waves (e.g., beam waves 412 and 413) and allowing only on-axis beam waves (e.g., beam wave 411) to pass through during single beam mode.

Referring now to fig. 5A and 5B, fig. 5A and 5B are schematic diagrams of a multi-beam e-beam tool 500 illustrating an exemplary configuration of a movable aperture plate 573, consistent with an embodiment of the present disclosure. The multi-beam e-beam tool 500 may be part of a multi-beam apparatus (e.g. the multi-beam apparatus 40 of fig. 2).

Similar to the previously described embodiments, the multi-beam electron beam tool 500 may include an electron source 501, a gun aperture plate 571, a beam pre-shaping aperture array 572, a condenser lens 510, and a movable aperture plate 573. Fig. 5A and 5B show additional embodiments of multi-beam electron beam tools having different configurations of movable aperture plates. In some embodiments, the condenser lens 510 may include two or more lenses that operate in combination to alter the path of the primary electron beam wave. The two or more lenses may be electrostatic lenses, magnetic lenses, or a combination of both. For example, FIG. 5A shows an embodiment of a condenser lens 510 that includes two magnetic lenses 510a and 510 b. In such an embodiment, as shown in fig. 5B, the movable aperture plate 573 may be moved to a position between the two magnetic lenses 510a and 510B to block off-axis electron beam waves 512, 513, thereby enabling single beam mode operation. It should be understood that the movable orifice plate 573 may be of various shapes. For example, the movable orifice plate 573 may be a rectangular plate as shown in fig. 3C. In some embodiments, the movable orifice plate may be a circular plate having a plurality of orifices. In such embodiments, the circular aperture plate may be rotated so that different sized apertures are aligned with the optical axis to allow electrons to pass through. The rotating circular aperture plate may be suitable for use in small spaces, such as in condenser lens 510.

Referring now to fig. 6A, 6B, and 6C, fig. 6A, 6B, and 6C are schematic diagrams of a multi-beam e-beam tool 600 illustrating an exemplary configuration of a movable orifice plate 673 consistent with embodiments of the present disclosure. The multi-beam e-beam tool 600 may be part of a multi-beam apparatus (e.g. the multi-beam apparatus 40 of fig. 2).

Similar to the previously described embodiments, the multi-beam electron beam tool 600 may comprise an electron source 601, a beam pre-shaping aperture array 672, a condenser lens 610 and a movable aperture plate 673. In some embodiments, as shown in fig. 6A and 6B, the gun plate may be replaced with a movable orifice plate 673 that includes two or more orifices therein, with a first orifice (e.g., orifice 673a of fig. 6C) for the single beam mode and a second orifice (e.g., orifice 673B of fig. 6C) for the multiple beam mode.

For example, in single beam mode, as shown in fig. 6A, the movable aperture plate 673 may be moved to a first position over the beam pre-shaping aperture array 672. When the movable orifice plate 673 is placed in the first position, a first orifice of the movable orifice plate 673 (e.g., orifice 673a of fig. 6C) is aligned with the primary optical axis 604. The first aperture may include a small opening configured to trim off-axis portions of the primary electron beam 602, thereby generating a single beam wave, such as electron beam wave 611, after the beam pre-forming aperture array 672.

In the multi-beam mode, as shown in fig. 6B, the movable orifice plate 673 may be moved to a second position. When the movable orifice plate 673 is placed in the second position, a second orifice of the movable orifice plate 673 (e.g., orifice 673b of fig. 6C) is aligned with the primary optical axis 604. The second aperture may include a larger opening that is capable of passing a larger portion of the primary electron beam 602, thereby generating a plurality of beam waves: an on-axis beam (e.g., beam 611) and an off-axis beam (e.g., beams 612 and 613). In such embodiments, the second aperture may effectively function as a gun aperture array in multi-beam mode (e.g., gun aperture array 371 of fig. 3B) by passing a sufficiently large portion of the primary electron beam 602 to generate multiple beam waves while blocking peripheral electrons of the primary electron beam 602 to reduce coulomb effects.

Although fig. 6C illustrates a movable orifice plate having a rectangular shape, it is understood that movable orifice plate 673 may be a different shape. For example, the movable orifice plate 673 may be a circular plate having a plurality of orifices. The present disclosure does not limit the shape of the movable orifice 373.

Referring now to fig. 7A and 7B, fig. 7A and 7B are schematic diagrams of a multi-beam e-beam tool 700 illustrating an exemplary configuration of secondary electron detection devices 740 and 746 consistent with embodiments of the present disclosure. Fig. 7A illustrates a multi-beam mode of operation of the multi-beam e-beam tool 700. Fig. 7B illustrates a single beam mode of operation of the multi-beam e-beam tool 700.

In some embodiments, the multi-beam electron tool 700 may include an objective lens 731, the objective lens 731 configured to focus the beam waves 711, 712, and 713 onto the sample 708 for inspection and may form three probe points 721, 722, and 723 on the surface of the sample 708. The multi-beam e-beam tool 700 may comprise a multi-beam inspection device 740 and a single-beam inspection device 746, the multi-beam inspection device 740 and the single-beam inspection device 746 being configured to inspect secondary electrons during the multi-beam mode and the single-beam mode, respectively. The multi-beam detection device 740 may be aligned with the secondary optical axis 751. The single beam detection device 746 may be aligned with the primary optical axis 704.

The multi-beam e-beam tool 700 may further comprise a beam splitter 733, the beam splitter 733 being configured to deflect the secondary electrons in different directions based on an operation mode of the multi-beam e-beam tool 700. For example, as shown in fig. 7A, in the multi-beam mode, the beam splitter 733 may be configured to deflect the secondary electron beams 761, 762, and 763 along the secondary optical axis 751 toward the multi-beam detecting device 740. On the other hand, in single beam mode, as shown in fig. 7B, beam splitter 733 may be disabled such that secondary electron beam 761 may be detected by single beam detection device 746, which may be specially designed to enhance detection of secondary electrons generated by a single beam (e.g., primary beam 711).

Referring now to fig. 8A and 8B, fig. 8A and 8B are schematic diagrams of a multi-beam e-beam tool 800 illustrating an exemplary configuration of secondary electron detection devices 840 and 846, consistent with an embodiment of the present disclosure. Fig. 8A illustrates a multi-beam mode of operation of the multi-beam e-beam tool 800. Fig. 8B illustrates a single beam mode of operation of the multi-beam e-beam tool 800.

The multi-beam e-beam tool 800 may operate in a similar manner as previously described with respect to fig. 7A and 7B. During the multi-beam mode, the beam splitter 833 may be configured to deflect the secondary electron beams 861, 862, and 863 along the secondary optical axis 851 towards the multi-beam detection device 840. During the single beam mode, beam splitter 833 may be configured to be disabled so that secondary electron beam 861 may be detected by single beam detection device 846, which single beam detection device 846 may be specifically designed to detect a single secondary electron beam.

However, one significant difference between the multi-beam e-beam tool 800 and the multi-beam e-beam tool 700 of fig. 7A and 7B is that, in some embodiments, the single beam detector 846 may be movable. For example, during a multi-beam mode, as shown in fig. 8A, single beam detection device 846 may be moved away from main optical axis 804 to create space for multiple beams (e.g., beams 811, 812, and 813) to pass through. During the single beam mode, as shown in fig. 8B, the single beam detection device 846 may be moved to a position aligned with the main optical axis 804 to detect the secondary electron beam 861. Because the single beam detection device 846 is moved away during the multi-beam mode, the single beam detection device 846 may be larger than stationary designs (e.g., the single beam detection device 746 of FIG. 7A) to enable the ability to provide higher resolution during single beam mode inspection.

Referring now to fig. 9A, 9B, and 9C, fig. 9A, 9B, and 9C are schematic diagrams of a multi-beam e-beam tool 900 illustrating exemplary configurations of secondary electron detection devices 940 and 946 consistent with embodiments of the present disclosure. The multi-beam e-beam tool 900 may be part of a multi-beam apparatus (e.g. the multi-beam apparatus 40 of fig. 2). Fig. 9A illustrates a multi-beam mode of operation of the multi-beam e-beam tool 900. Fig. 9B and 9C illustrate a single beam mode of operation of the multi-beam e-beam tool 900.

The multi-beam e-beam tool 900 may operate in a similar manner as previously described with respect to fig. 7A and 7B. During the multi-beam mode, the beam splitter 933 may be configured to deflect the secondary electron beams 961, 962, and 963 along the first auxiliary optical axis 951 towards the multi-beam detection device 940.

However, one significant difference between the multi-beam e-beam tool 900 and the multi-beam e-beam tool 700 of fig. 7A and 7B is that, in some embodiments, the single beam detection device 946 may not be aligned with the primary optical axis 904. In such embodiments, during the single beam mode, the beam splitter 933 can be configured to deflect the secondary electron beam 961 towards the single beam detector 946, which single beam detector 946 can be aligned with the second secondary optical axis 952, as shown in fig. 9B. In some embodiments, the first secondary optical axis 951 and the second secondary optical axis 952 are symmetric with respect to the primary optical axis 904. However, it should be understood that optical axes 951 and 952 may be asymmetric.

As shown in fig. 9C, in some embodiments, the multi-beam e-beam tool 900 may further include an energy filter 947 in front of the single beam detection device 946. The energy filter 947 may also be aligned with the second secondary optical axis 952. The energy filter 947 may be configured to enhance detection of backscattered electrons, which are typically of higher energy than ordinary secondary electrons. In some embodiments, the energy filter 947 may selectively allow electrons having a particular energy level to pass through. For example, the energy filter 947 may be tuned to pass only high energy electrons (e.g., backscattered electrons) so that more backscattered electrons than normal secondary electrons can reach the single beam detection device 946.

Referring now to fig. 10A and 10B, fig. 10A and 10B are schematic diagrams of a multi-beam e-beam tool 1000 illustrating an exemplary configuration of secondary electron detection devices 1046 and 1080 consistent with an embodiment of the present disclosure.

The multi-beam tool 1000 may operate in a similar manner as the multi-beam tool 700 or 800 previously described with respect to fig. 7A/7B and 8A/8B, respectively. When the multi-beam electron beam tool 1000 is operating in a multi-beam mode, the beam splitter 1033 may be configured to deflect the secondary electron beam 1061 towards the multi-beam detection device 1040. When the multi-beam electron beam tool 1000 is operating in the single-beam mode, as shown in fig. 10A and 10B, the beam splitter 1033 may be configured to be disabled such that the secondary electron beam 1061 may be detected by the single-beam detection device 1046, which single-beam detection device 1046 may be specifically designed to detect the single-beam secondary electron beam. In some embodiments, the single beam detection device 1046 is immovable, similar to the single beam detection device 746 of fig. 7A and 7B. In some embodiments, the single beam detection device 1046 is movable, similar to the single beam detection device 846 in fig. 8A and 8B.

In response to the primary beam wave 1011 being incident on the sample 1008, a secondary electron beam may be emitted from the sample 1008. The secondary electron beam may include secondary electrons (e.g., 1061) and backscattered electrons (e.g., 1081, 1082, and 1083), as shown in fig. 10A and 10B. The secondary electrons 1061 have a low emission energy and are therefore easily focused by the objective lens 1031 to be detected by the single beam detection device 1046. The backscatter has a high electron emission energy, and thus is difficult to be focused by the objective lens 1031. Thus, only backscattered electrons with a small emission angle (such as 1081) may be detected by the single beam detection device 1046.

However, as shown in fig. 10A, backscattered electrons having a larger emission angle (e.g., 1082 and 1083) may not be sufficiently focused during the single beam mode and may not be detected by the single beam detection device 1046. In some embodiments, capturing backscattered electrons having larger emission angles (e.g., beams 1082 and 1083) may be useful for defect inspection, as those backscattered electrons may include topographical and material information about the sample 1008.

As shown in fig. 10B, in some embodiments, additional single beam detection devices 1080 may be used to capture backscattered electrons having larger emission angles. An additional single beam detection device 1080 may be placed between the objective lens 1031 and the sample 1008.

In some embodiments, the additional single beam detection device 1080 may be non-movable, similar to the single beam detection device 746 of fig. 7A and 7B. In such embodiments, the additional single beam detection device 1080 may be designed with an inner bore diameter 1095 large enough to avoid blocking the primary electron beam (e.g., beam 811, 812, 813 in fig. 8A) and the secondary electron beam (e.g., secondary 861, 862, 863) when the multi-beam electron beam tool 1000 is operating in the multi-beam mode.

In some embodiments, the additional single beam detection device 1080 may be movable similar to the single beam detection device 846 in fig. 8A and 8B. For example, during multi-beam mode, the additional single-beam detection device 1080 may be moved away from the main optical axis 1004 to create space for the multiple beam waves to pass through. During the single beam mode, as shown in FIG. 10B, an additional single beam detection device 1080 may be moved into alignment with the main optical axis 1004 to detect backscattered electrons having a larger emission angle, such as backscattered electrons 1082 and 1083.

Because the additional single beam detection device 1080 is removed during the multi-beam mode, the additional single beam detection device 1080 can be optimized to collect backscattered electrons when operating in the single beam mode. For example, the inner bore diameter 1095 of the additional single beam detection device 1080 may be smaller than the fixed design, thereby creating a larger detection area. Such optimization may provide the ability to capture more backscattered electrons, which may improve imaging resolution and inspection throughput of the sample 1008 during single beam mode inspection.

In some embodiments, capturing secondary and backscattered electrons according to emission angle may be more helpful for defect inspection, as this information is related to the pattern orientation on the sample surface or inside the sample. Thus, the single beam detection device 1046 and the additional single beam detection device 1080 may include multiple detection areas or be segmented, as shown in fig. 10C, 10D, and 10E.

Referring now to fig. 10C, 10D, and 10E, fig. 10C, 10D, and 10E illustrate schematic diagrams of an exemplary embodiment of the additional single beam detection device 1080 of fig. 10B consistent with embodiments of the present disclosure. In some embodiments, the additional single beam detection device 1080 may comprise a single annular detection region 1080a, as shown in fig. 10C.

Backscattered electrons emitted from a sample (e.g., sample 1008 of fig. 10B) may provide different information depending on the shape and orientation of features implemented within the sample. Thus, in some embodiments, additional secondary electron detection device 1080 may include multiple segments of detection areas so that more specific information about features on the sample may be acquired.

Fig. 10D shows an example of an additional single beam detection device 1080. In some embodiments, the additional single beam detection device 1080 may include detection segments 1080b, 1080c, 1080d, and 1080e positioned along the direction of rotation 1096. This enables detection of backscattered electrons in terms of their azimuthal emission angle (emission angle in the circumferential direction) and facilitates defect inspection of certain types of samples.

Fig. 10E shows another example of an additional single beam detection device 1080. In some embodiments, the additional single beam detection device 1080 may include detection segments 1080f and 1080g positioned along the radial direction 1097. This enables the detection of backscattered electrons in terms of their emission radial angle (emission angle relative to the surface normal) and facilitates defect inspection of certain types of samples.

In some embodiments, the single beam detection device 1046 of fig. 10A and 10B can include a single annular detection region (e.g., the single annular detection region 1080A shown in fig. 10) or a plurality of detection segments (e.g., the rotationally arranged detection segments 1080B-1080E in fig. 10D or the radially arranged detection segments 1080f-1080g in fig. 10E).

Referring now to fig. 11, fig. 11 is a flow chart illustrating an exemplary method of inspecting a specimen using a multi-beam e-beam tool (e.g., multi-beam e-beam tool 300 of fig. 3A) consistent with embodiments of the present disclosure. In some embodiments, the multi-beam electron beam tool may include an electron source (e.g., electron source 301 of fig. 3A), a gun plate (e.g., gun plate 371 of fig. 3A), a beam pre-shaping aperture array (e.g., beam pre-shaping aperture array 372), and a condenser lens (e.g., condenser lens 310 of fig. 3A). The electron source is configured to emit primary electrons and form a primary electron beam (e.g., primary electron beam 302 of fig. 3A). The gun aperture plate is configured to block peripheral electrons of the primary electron beam to reduce coulomb effects, which may reduce detection resolution. In some embodiments, the array of beam pre-forming apertures further slices the peripheral electrons of the primary electron beam to reduce coulombic effects. After passing through the beam wave pre-forming aperture array, the primary electron beam may be tailored into a plurality of primary electron beam waves (e.g., electron beam waves 311, 312, and 313 in fig. 3A).

In some embodiments, the multi-beam electron beam tool may further comprise a movable aperture plate (e.g., the movable aperture plate 373 of fig. 3A and 3B) that may be used to support multiple operating modes of the electron beam tool, such as a single beam mode and a multi-beam mode. In some embodiments, the multi-beam e-beam tool may further comprise a controller having circuitry and configured to change a configuration of the multi-beam e-beam tool to switch between the multi-beam mode and the single-beam mode.

In step 1110, a sample is loaded into a multi-beam electron beam tool for inspection. In step 1120, the controller enables the movable aperture plate to move from a first position to a second position to perform a multi-beam inspection of the sample when the multi-beam electron beam tool is placed in a multi-beam mode inspection. In some embodiments, in the multi-beam mode, the movable orifice plate may be in a second position, in which the movable orifice plate is sufficiently far away from the path of the plurality of primary electron beam waves that those primary beam waves will pass through.

In step 1130, when the multi-beam electron beam tool is placed in the single-beam mode, the controller enables the movable well plate to move from the second position to the first position to perform a single-beam high resolution inspection of the sample. In some embodiments, the aperture of the movable aperture plate may be aligned with the primary optical axis when the movable aperture plate is placed in the first position. The movable aperture plate may be configured to block off-axis primary electron beam waves (e.g., beam waves 312 and 313 of fig. 3A) and allow only on-axis beam waves (e.g., beam wave 311 of fig. 3A) to pass through during the single beam mode.

The embodiments may be further described using the following clauses:

1. a charged particle beam apparatus for inspecting a sample supporting multiple modes of operation, comprising:

a charged particle beam source configured to emit a charged particle beam along a primary optical axis;

a first aperture plate configured to form a plurality of charged particle beam waves from a charged particle beam;

a second orifice plate movable between a first position and a second position; and

a controller having circuitry and configured to change a configuration of the device to switch between a first mode and a second mode, wherein:

in a first mode:

the second orifice plate being in the first position, an

The first aperture plate and the second aperture plate are configured to allow a first charged particle beam wave of the plurality of charged particle beam waves to pass through, and

in a second mode:

the second orifice plate is in a second position, an

The first aperture plate and the second aperture plate are configured to allow a first charged particle beam wave and a second charged particle beam wave of the plurality of charged particle beam waves to pass through.

2. The apparatus according to clause 1, wherein the first mode is a single beam mode and the second mode is a multiple beam mode.

3. The apparatus according to any of clauses 1 to 2, wherein the first charged particle beam is an on-axis beam with respect to a primary optical axis and the second charged particle beam is an off-axis beam with respect to the primary optical axis.

4. The apparatus according to any of clauses 1-3, wherein the second orifice plate is configured to: the second charged particle beam wave is blocked when the apparatus is operating in the first mode.

5. The apparatus according to any of clauses 1 to 4, wherein the first aperture plate is located between the charged particle beam source and the second aperture plate when the apparatus is operated in the first mode.

6. The apparatus according to any of clauses 1 to 5, further comprising:

a condenser lens configured to change paths of the plurality of charged particle beam waves to form a plurality of images of the charged particle beam source on an image plane.

7. The apparatus according to clause 6, wherein the second aperture plate is positioned between the first aperture plate and the condenser lens when the apparatus is operated in the first mode.

8. The apparatus according to clause 6, wherein the condenser lens is located between the first aperture plate and the second aperture plate when the apparatus is operated in the first mode.

9. The apparatus according to clause 6, wherein the condenser lens comprises a first deflector and a second deflector, and wherein the second aperture plate is located between the first deflector and the second deflector when the apparatus is operated in the first mode.

10. The apparatus according to any of clauses 1 to 4, wherein the second aperture plate is located between the charged particle beam source and the first aperture plate when the apparatus is operated in the first mode.

11. The apparatus according to any of clauses 1 to 10, further comprising:

a beam splitter configured to deflect secondary electrons generated from a sample; and

first electron detection means configured to detect secondary electrons when the device is operating in the first mode or the second mode.

12. The apparatus of clause 11, wherein the controller includes circuitry for:

in the first mode or the second mode, the beam splitter is controlled to deflect the secondary electrons towards a first electron detection device, wherein the first electron detection device is aligned with the first auxiliary optical axis.

13. The apparatus according to any of clauses 1 to 10, further comprising:

a beam splitter configured to deflect secondary electrons generated from a sample;

first electron detection means configured to detect secondary electrons when the apparatus is operating in a second mode; and

second electron detection means configured to detect secondary electrons when the apparatus is operating in the first mode.

14. The apparatus of clause 13, wherein the controller includes circuitry for:

in a second mode, the beam splitter is controlled to deflect the secondary electrons towards a first electron detection device, wherein the first electron detection device is aligned with the first auxiliary optical axis, and

in the first mode, the beam splitter is disabled to allow secondary electrons to travel toward the second electron detection device.

15. The apparatus according to clause 14, wherein the second electronic detection device is aligned with the primary optical axis.

16. The apparatus according to clause 14, wherein the second electronic detection device is movable between a third position and a fourth position, wherein:

if the device is configured in the first mode, the second electron detection means are in a third position for detecting secondary electrons, the second electron detection means being aligned with the main optical axis when in the third position, an

If the device is configured in the second mode, the second electronic detection means is located in a fourth position, in which the second electronic detection means is distant from the main optical axis.

17. The apparatus of clause 13, wherein the controller includes circuitry for:

during a second mode, controlling the beam splitter to deflect the secondary electrons towards a first electron detection device, wherein the first electron detection device is aligned with the first auxiliary optical axis, and

during the first mode, the beam splitter is controlled to deflect the secondary electrons towards a second electron detection device, wherein the second electron detection device is aligned with the second auxiliary optical axis.

18. The apparatus according to clause 17, wherein the first secondary optical axis and the second secondary optical axis are symmetric about the primary optical axis.

19. The apparatus according to any of clauses 17 and 18, wherein the second electron detection device comprises an electron detector for detecting secondary electrons and an energy filter in front of the electron detector for enhancing the detection of backscattered electrons.

20. The apparatus according to any of clauses 1 to 10, further comprising:

a beam splitter configured to deflect secondary electrons generated from a sample;

first electron detection means configured to detect secondary electrons when the apparatus is operating in a second mode;

second electron detection means configured to detect a first portion of the secondary electrons when the apparatus is operating in the first mode; and

third electron detection means configured to detect a second portion of the secondary electrons when the apparatus is operating in the first mode.

21. The device according to clause 20, wherein the second portion of the secondary electrons comprises electrons having an energy higher than that of the electrons of the first portion of the secondary electrons.

22. The apparatus according to clause 20, wherein the second portion of secondary electrons comprises electrons having an emission angle greater than that of the electrons of the first portion of secondary electrons.

23. The apparatus according to any of clauses 20 to 22, wherein the second portion of the secondary electrons comprises backscattered electrons emitted from the sample.

24. The apparatus according to any of clauses 20 to 23, wherein the second and third electronic detection devices are aligned with the primary optical axis.

25. The apparatus according to any of clauses 20 to 23, wherein:

a third electron detection means aligned with the main optical axis for detecting a second portion of the secondary electrons, an

The second electronic detection device is movable between a third position and a fourth position, wherein:

if the device is configured in the first mode, the second electron detection means are located in a third position for detecting the first part of the secondary electrons, the second electron detection means being aligned with the main optical axis when in the third position, an

If the device is configured in the second mode, the second electronic detection means is located in a fourth position, in which the second electronic detection means is distant from the main optical axis.

26. The apparatus according to any of clauses 20 to 23, wherein:

a second electron detection device aligned with the main optical axis for detecting a first portion of the secondary electrons, an

The third electronic detection device is movable between a fifth position and a sixth position, wherein:

if the device is configured in the first mode, the third electron detection means are located in a fifth position for detecting the second portion of the secondary electrons, the third electron detection means being aligned with the main optical axis when in the fifth position, an

If the device is configured in the second mode, the third electronic detection means is located in a sixth position, in which the third electronic detection means is distant from the main optical axis.

27. The apparatus according to any of clauses 20 to 23, wherein:

the second electronic detection device is movable between a third position and a fourth position, and

the third electronic detection device is movable between a fifth position and a sixth position, wherein:

if the device is configured in the first mode, the second electron detection means are in a third position to detect a first portion of the secondary electrons, the second electron detection means are aligned with the main optical axis in the third position, and the third electron detection means are in a fifth position to detect a second portion of the secondary electrons, the third electron detection means are aligned with the main optical axis in the fifth position, and

if the device is configured in the second mode, the second electronic detection means is located in a fourth position and the third electronic detection means is located in a sixth position, wherein the second electronic detection means and the third electronic detection means are located away from the main optical axis.

28. The apparatus according to any of clauses 20 to 27, wherein the second electronic detection device comprises a plurality of detection segments, the third electronic detection device comprises a plurality of detection segments, or the second electronic detection device and the third electronic detection device comprise a plurality of detection segments.

29. The apparatus according to any of clauses 1 to 28, wherein the second orifice plate comprises a first orifice, wherein:

if the device is configured in the first mode, the second aperture plate is in the first position such that the first aperture is aligned with the main optical axis, an

If the device is configured in the second mode, the second aperture plate is in the second position such that the first aperture is remote from the main optical axis.

30. The apparatus according to clause 29, wherein the second orifice plate further comprises a second orifice larger than the first orifice, wherein:

if the device is configured in the third mode, the second aperture is located in a fifth position such that the second aperture is aligned with the main optical axis to block the second charged particle beam wave and to produce a higher current detection point on the sample than the first aperture.

31. The apparatus according to any of clauses 1 to 28, wherein the second orifice plate comprises a first orifice and a second orifice, wherein:

if the device is configured in the first mode, the second aperture plate is in the first position such that the first aperture is aligned with the main optical axis, an

If the device is configured in the second mode, the second aperture plate is in the second position such that the second aperture is aligned with the main optical axis.

32. The apparatus according to clause 31, wherein the second aperture is larger than the first aperture.

33. The apparatus according to any of clauses 1 to 32, wherein the second orifice plate is a circular plate.

34. The apparatus according to clause 33, wherein the second aperture plate rotates about the primary optical axis.

35. A method of inspecting a sample using a charged particle beam device, the charged particle beam device comprising a first aperture plate configured to form a plurality of charged particle beam waves from a charged particle beam emitted by a charged particle beam source, the method comprising:

moving the second orifice plate from the second position to the first position, wherein:

positioning the second aperture plate in a first position such that a single charged particle beam wave of the charged particle beam can pass through the combination of the first aperture plate and the second aperture plate, and

positioning the second aperture plate in the second position enables a plurality of charged particle beam waves of the charged particle beam to pass through a combination of the first aperture plate and the second aperture plate.

36. The method of clause 35, further comprising:

the second orifice plate is moved from the first position to the second position.

37. The method according to any of clauses 35 and 36, wherein the single charged particle beam wave is an on-axis charged particle beam wave relative to the primary optical axis.

38. The method according to any of clauses 35 to 37, wherein the second aperture plate is configured to block the off-axis charged particle beam wave when located in the first position.

39. A charged particle beam apparatus for inspecting a sample supporting multiple modes of operation, comprising:

a charged particle beam source configured to emit a charged particle beam along a primary optical axis;

a movable orifice plate movable between a first position and a second position; and

a controller having circuitry and configured to change a configuration of the device to switch between a first mode and a second mode, wherein:

in a first mode:

the movable aperture plate is located at a first position and is configured to allow a first charged particle beam wave of a plurality of charged particle beam waves derived from the charged particle beam to pass through, an

In a second mode:

the movable aperture plate is located at a second position and is configured to allow a first charged particle beam wave and a second charged particle beam wave of the plurality of charged particle beam waves to pass through.

40. The apparatus of clause 39, wherein the first mode is a single beam mode and the second mode is a multiple beam mode.

41. The apparatus according to any of clauses 39 to 40, wherein the first charged particle beam is an on-axis beam with respect to the primary optical axis and the second charged particle beam is an off-axis beam with respect to the primary optical axis.

42. The apparatus according to any of clauses 39 to 41, wherein the movable aperture plate is configured to block the second charged particle beam wave when the apparatus is operated in the first mode.

43. The apparatus according to any of clauses 39 to 42, further comprising a pre-formed beam aperture plate, wherein the pre-formed beam aperture plate is located between the charged particle beam source and the movable aperture plate when the apparatus is operated in the first mode.

44. The apparatus according to any of clauses 39 to 43, further comprising:

a condenser lens configured to change paths of the plurality of charged particle beam waves to form a plurality of images of the charged particle beam source on an image plane.

45. The apparatus according to clause 44, wherein the movable aperture plate is located between the beam pre-forming aperture plate and the condenser lens when the apparatus is operated in the first mode.

46. The apparatus according to clause 44, wherein the condenser lens is located between the beam pre-forming aperture plate and the movable aperture plate when the apparatus is operated in the first mode.

47. The apparatus according to clause 44, wherein the condenser lens comprises a first deflector and a second deflector, and wherein the movable aperture plate is located between the first deflector and the second deflector when the apparatus is operated in the first mode.

48. The apparatus according to any of clauses 39 to 42, further comprising a beam pre-forming aperture plate, wherein the movable aperture plate is located between the charged particle beam source and the beam pre-forming aperture plate when the apparatus is operated in the first mode.

49. The apparatus of any of clauses 39 to 48, further comprising:

a beam splitter configured to deflect secondary electrons generated from a sample; and

first electron detection means configured to detect secondary electrons when the device is operating in the first mode or the second mode.

50. The apparatus of clause 49, wherein the controller comprises circuitry to:

in the first mode or the second mode, the beam splitter is controlled to deflect the secondary electrons towards a first electron detection device, wherein the first electron detection device is aligned with the first auxiliary optical axis.

51. The apparatus of any of clauses 39 to 48, further comprising:

a beam splitter configured to deflect secondary electrons generated from a sample;

first electron detection means configured to detect secondary electrons when the apparatus is operating in a second mode; and

second electron detection means configured to detect secondary electrons when the apparatus is operating in the first mode.

52. The apparatus of clause 51, wherein the controller comprises circuitry for:

in a second mode, the beam splitter is controlled to deflect the secondary electrons towards a first electron detection device, wherein the first electron detection device is aligned with the first auxiliary optical axis, and

in the first mode, the beam splitter is disabled to allow secondary electrons to travel toward the second electron detection device.

53. The apparatus of clause 52, wherein the second electronic detection device is aligned with the primary optical axis.

54. The apparatus according to clause 52, wherein the second electronic detection device is movable between a third position and a fourth position, wherein:

if the device is configured in the first mode, the second electron detection means are in a third position for detecting secondary electrons, the second electron detection means being aligned with the main optical axis when in the third position, an

If the device is configured in the second mode, the second electronic detection means is located in a fourth position, in which the second electronic detection means is distant from the main optical axis.

55. The apparatus of clause 51, wherein the controller comprises circuitry for:

during a second mode, controlling the beam splitter to deflect the secondary electrons towards a first electron detection device, wherein the first electron detection device is aligned with the first auxiliary optical axis, and

during the first mode, the beam splitter is controlled to deflect the secondary electrons towards a second electron detection device, wherein the second electron detection device is aligned with the second auxiliary optical axis.

56. The device according to clause 55, wherein the first secondary optical axis and the second secondary optical axis are symmetric about the primary optical axis.

57. The apparatus according to any of clauses 55 and 56, wherein the second electron detection device comprises an electron detector for detecting secondary electrons and an energy filter in front of the electron detector for enhancing the detection of backscattered electrons.

58. The apparatus of any of clauses 39 to 48, further comprising:

a beam splitter configured to deflect secondary electrons generated from a sample;

first electron detection means configured to detect secondary electrons when the apparatus is operating in a second mode;

second electron detection means configured to detect a first portion of the secondary electrons when the apparatus is operating in the first mode; and

third electron detection means configured to detect a second portion of the secondary electrons when the apparatus is operating in the first mode.

59. The apparatus of clause 58, wherein the second portion of the secondary electrons comprises electrons having an energy higher than that of the electrons of the first portion of the secondary electrons.

60. The apparatus according to clause 58, wherein the second portion of the secondary electrons comprises electrons having an emission angle greater than that of the electrons of the first portion of the secondary electrons.

61. The apparatus according to any of clauses 58 to 60, wherein the second portion of the secondary electrons comprises backscattered electrons emitted from the sample.

62. The apparatus according to any of clauses 58 to 61, wherein the second and third electronic detection devices are aligned with the primary optical axis.

63. The apparatus of any of clauses 58 to 62, wherein:

a third electron detection means aligned with the main optical axis for detecting a second portion of the secondary electrons, an

The second electronic detection device is movable between a third position and a fourth position, wherein:

if the device is configured in the first mode, the second electron detection means are located in a third position for detecting the first part of the secondary electrons, the second electron detection means being aligned with the main optical axis when in the third position, an

If the device is configured in the second mode, the second electronic detection means is located in a fourth position, in which the second electronic detection means is distant from the main optical axis.

64. The apparatus of any of clauses 58 to 62, wherein:

a second electron detection device aligned with the main optical axis for detecting a first portion of the secondary electrons, an

The third electronic detection device is movable between a fifth position and a sixth position, wherein:

if the device is configured in the first mode, the third electron detection means are located in a fifth position for detecting the second portion of the secondary electrons, the third electron detection means being aligned with the main optical axis when in the fifth position, an

If the device is configured in the second mode, the third electronic detection means is located in a sixth position, in which the third electronic detection means is distant from the main optical axis.

65. The apparatus of any of clauses 58 to 62, wherein:

the second electronic detection device is movable between a third position and a fourth position, and

the third electronic detection device is movable between a fifth position and a sixth position, wherein:

if the device is configured in the first mode, the second electron detection means are in a third position to detect a first portion of the secondary electrons, the second electron detection means are aligned with the main optical axis in the third position, and the third electron detection means are in a fifth position to detect a second portion of the secondary electrons, the third electron detection means are aligned with the main optical axis in the fifth position, and

if the device is configured in the second mode, the second electronic detection means is located in a fourth position and the third electronic detection means is located in a sixth position, wherein the second electronic detection means and the third electronic detection means are located away from the main optical axis.

66. The device according to any of clauses 58 to 65, wherein the second electronic detection means comprises a plurality of detection segments and the third electronic detection means comprises a plurality of detection segments, or the second electronic detection means and the third electronic detection means comprise a plurality of detection segments.

67. The apparatus according to any of clauses 39 to 66, wherein the movable orifice plate comprises a first orifice, wherein:

if the device is configured in the first mode, the movable aperture plate is in the first position such that the first aperture is aligned with the main optical axis, an

If the device is configured in the second mode, the movable aperture plate is in the second position such that the first aperture is away from the main optical axis.

68. The apparatus according to clause 67, wherein the movable orifice plate further comprises a second orifice larger than the first orifice, wherein:

if the device is configured in the third mode, the second aperture is located in a fifth position such that the second aperture is aligned with the main optical axis to block the second charged particle beam wave and to produce a higher current detection point on the sample than the first aperture.

69. The apparatus according to any of clauses 39 to 66, wherein the movable orifice plate comprises a first orifice and a second orifice, wherein:

if the device is configured in the first mode, the movable aperture plate is in the first position such that the first aperture is aligned with the main optical axis, an

If the device is configured in the second mode, the movable aperture plate is in the second position such that the second aperture is aligned with the main optical axis.

70. The apparatus of clause 69, wherein the second aperture is larger than the first aperture.

71. The apparatus according to any of clauses 39 to 70, wherein the movable orifice plate is a circular plate.

72. The apparatus according to clause 71, wherein the movable aperture plate rotates about a primary optical axis.

A non-transitory computer readable medium may be provided that stores instructions for a processor of a controller (e.g., controller 50 of fig. 1) to perform a mode switch of operation between a multi-beam mode and a single-beam mode (e.g., control the beam splitter or single-beam detection device of fig. 8A and 8B). Common forms of non-transitory media include, for example, a floppy disk, a flexible disk, hard disk, solid state drive, magnetic tape, or any other magnetic data storage medium, a compact disc read only memory (CD-ROM), any other optical data storage medium, any physical medium with patterns of holes, a Random Access Memory (RAM), a Programmable Read Only Memory (PROM), and Erasable Programmable Read Only Memory (EPROM), a FLASH-EPROM, or any other FLASH memory, a non-volatile random access memory (NVRAM), a cache, a register, any other memory chip or cartridge, and network versions thereof.

It is to be understood that the embodiments of the present disclosure are not limited to the exact configurations that have been described above and illustrated in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The disclosure has been described in conjunction with various embodiments, and other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.

The above description is intended to be illustrative, and not restrictive. Thus, it will be apparent to one skilled in the art that the modifications described may be made without departing from the scope of the claims set out below.