阅读说明：本技术 控制带电粒子束的能量散布的装置和方法 (Apparatus and method for controlling energy spread of charged particle beam ) 是由 S·B·汉森 任岩 M·R·古森 A·V·G·曼格努斯 E·P·斯马克曼 于 2020-02-04 设计创作，主要内容包括：在各方面中尤其地公开了一种带电粒子检查系统,其包括吸收部件和可编程带电粒子反射镜板,该可编程带电粒子反射镜板被布置为修改束中电子的能量分布并且对束进行整形以减少电子的能量散布和束的像差,其中吸收部件包括限定腔的结构,该腔具有内部表明以及设置在内部表上的超材料吸收体。在操作中,腔沿着束路径的一部分延伸。在其他实施例中,超材料包括吸收结构集合,该吸收结构集合被配置为设置在透明导电层上的吸收结构。进一步,公开了一种使用这种吸收部件并且使用可编程带电粒子反射镜板的方法,其中这种可编程带电粒子反射镜板包括像素集合,该像素集合被配置为生成定制电场以对束进行整形。(Disclosed in various aspects, among others, is a charged particle inspection system that includes an absorber component and a programmable charged particle mirror plate arranged to modify an energy distribution of electrons in a beam and shape the beam to reduce energy spreading of the electrons and aberrations of the beam, wherein the absorber component includes a structure defining a cavity having an interior surface and a metamaterial absorber disposed on the interior surface. In operation, the cavity extends along a portion of the beam path. In other embodiments, the metamaterial includes a collection of absorbent structures configured as absorbent structures disposed on a transparent conductive layer. Further, a method of using such an absorptive component and using a programmable charged particle mirror plate is disclosed, wherein such a programmable charged particle mirror plate comprises a set of pixels configured to generate a customized electric field to shape a beam.)

1. An apparatus for narrowing the energy spread of a charged particle beam, the apparatus comprising:

a structure defining a cavity extending along a portion of a path of the charged particle beam, the cavity having an interior surface; and

a metamaterial absorber disposed on the interior surface.

2. The device of claim 1, wherein the metamaterial absorber comprises a layer of dielectric material on at least a portion of the interior surface, wherein the layer of transparent conductive material is provided with a plurality of absorbing structures.

3. The device of claim 1, wherein the metamaterial absorber comprises a layer of transparent conductive material on at least a portion of the interior surface, wherein the layer of transparent conductive material is provided with a plurality of absorbing structures.

4. The device of claim 3, wherein the absorbent structure is a metamaterial perfect absorber.

5. The apparatus of claim 3, wherein the absorbing structure is a plasmonic structure.

6. The apparatus of claim 3, wherein the absorbing structure resonantly absorbs electromagnetic energy.

7. The device of claim 3, wherein the absorbing structure is at least partially embedded in or coupled to the layer of transparent conductive material.

8. The device of claim 3, wherein the absorbing structure is fabricated on top of the layer of transparent conductive material.

9. The device of claim 3, wherein the absorbent structure is printed on the layer of transparent conductive material.

10. The apparatus of claim 3, wherein the absorbent structure comprises a plurality of bulk elements comprising a metallic material.

11. The device of claim 3, wherein the absorbing structure comprises graphene.

12. The device of claim 3, wherein the absorbent structure comprises a plurality of graphene sheets.

13. The apparatus of claim 3, wherein the absorbent structure comprises a combination of a plurality of bulk metal elements and a plurality of graphene sheets.

14. The device of claim 3, wherein the absorbent structures are arranged in a periodic array.

15. A method of reducing the width of an energy distribution in a charged particle beam, the method comprising the steps of: passing the beam through a volume of space defined by a structure extending along a path of the beam, the structure having a surface provided with a metamaterial absorber arranged to absorb energy from the charged particles.

Technical Field

Embodiments provided herein relate to charged particle apparatus having one or more charged particle beams, such as electron microscopy devices utilizing one or more electron beams.

Background

Integrated circuits are manufactured by creating a pattern on a wafer (also referred to as a substrate). The wafer is supported on a wafer stage in the apparatus for creating the pattern. A portion of the process for manufacturing integrated circuits includes viewing or "inspecting" various portions of the wafer. This can be done by scanning electron microscopy or SEM.

The use of SEM in lithography increasingly requires low electron detection energy to minimize radiation damage and mitigate charging effects. SEM observation requires extremely low landing energy to allow measurement of sub-surface and nanoscale information of the target sample with minimized depth of beam damage and minimized charging due to reduced interaction volume. However, as the detection energy decreases, the detrimental effects of objective chromatic aberration become significant, limiting the achievable spatial resolution. The energy spread of the beam can cause chromatic aberrations. The use of a monochromator may reduce this spread.

Disclosure of Invention

The following presents a simplified summary of one or more embodiments in order to provide a basic understanding of such embodiments. This summary is not an extensive overview of all contemplated embodiments, and is intended to neither identify key or critical elements of all embodiments nor delineate the scope of any or all embodiments. Its sole purpose is to present some concepts of one or more embodiments in a simplified form as a prelude to the more detailed description that is presented later.

According to one aspect of an embodiment, an apparatus and method for reducing energy spread of electrons in an electron beam using a monochromator comprising a metamaterial absorber is disclosed.

According to another aspect of an embodiment, an apparatus for narrowing the energy spread of an electron beam is disclosed, the apparatus comprising a structure defining a cavity extending along a portion of a path of the electron beam, the cavity having an interior surface; and a metamaterial absorber disposed on the interior surface. The metamaterial absorber may include a layer of dielectric material on at least a portion of the interior surface, wherein the layer of transparent conductive material may be provided with a plurality of absorbing structures. The metamaterial absorber may include a layer of transparent conductive material on at least a portion of the interior surface, wherein the layer of transparent conductive material may be provided with a plurality of absorbing structures. The absorbent structure may be a metamaterial perfect absorber. The absorbing structure may be a plasma structure. The absorbing structure may be configured to resonantly absorb electromagnetic energy. The absorbent structure may be at least partially embedded in the layer of transparent conductive material. The absorbing structure may be made on top of a layer of transparent conductive material. The absorbent structure may be printed on the layer of transparent conductive material. The absorbent structure may comprise a plurality of mass elements comprising a metallic material. The absorbent structure may comprise graphene. The absorbent structure may comprise a plurality of graphene sheets. The absorbent structure may comprise a combination of a plurality of bulk metal elements and a plurality of graphene sheets. The absorbent structures may be arranged in a periodic array. The pitch of the periodic array may be selected to achieve maximum absorption of energy from the electron beam. The transparent conductive material may include indium tin oxide. The transparent conductive material may include doped zinc oxide. The transparent conductive material may include carbon nanotubes. The transparent conductive material may include an amorphous material. The transparent conductive material may include a doped transparent semiconductor. The transparent conductive material may include a conductive polymer. The transparent conductive material may include a body including a transparent material and a coating of conductive material. The conductive material coating may comprise gold. The conductive material coating may comprise aluminum. The conductive material coating may comprise titanium. The conductive material coating may comprise chromium. The structure may comprise a substantially cylindrical column. The length of the portion of the column traversed by the electron beam may be selected to cause a predetermined amount of deceleration of the electrons in the electron beam. The substantially cylindrical post may comprise an electrically conductive material. The conductive material may include gold. The conductive material may include silver. The electron beam may propagate along the central axis of the column. The radius of the substantially cylindrical column may decrease in the direction of propagation of the electron beam. The size or pitch of the absorbing structure may vary along the direction in which the electron beam propagates.

According to another aspect of an embodiment, an apparatus for generating a substantially monochromatic electron beam is disclosed, the apparatus comprising an electron beam source; a monochromator comprising a metamaterial absorber arranged to interact with the electron beam to generate a substantially monochromatic electron beam; an objective lens arranged to focus the substantially monochromatic electron beam. The monochromator can include a structure defining a cavity having an interior surface; and a metamaterial absorber disposed on the interior surface. The metamaterial absorber may include a layer of dielectric material on at least a portion of the interior surface, wherein the layer of transparent conductive material may be provided with a plurality of absorbing structures. The metamaterial absorber may include a transparent conductive material layer on at least a portion of the interior surface, wherein the transparent conductive material layer may be provided with a plurality of absorbing structures. The absorbent structure may be a metamaterial perfect absorber. The absorbing structure may be a plasma structure. The absorbing structure may be configured to resonantly absorb electromagnetic energy. The absorbent structure may be at least partially embedded in the layer of transparent conductive material. The absorbing structure may be made on top of a layer of transparent conductive material. The absorbent structure may be printed on the layer of transparent conductive material. The absorbent structure may comprise a plurality of mass elements comprising a metallic material. The absorbent structure may comprise graphene. The absorbent structure may comprise a plurality of graphene sheets. The absorbent structure may comprise a combination of a plurality of bulk metal elements and a plurality of graphene sheets. The absorbent structures may be arranged in a periodic array. The pitch of the periodic array may be selected to achieve maximum absorption of energy from the electron beam. The transparent conductive material may include indium tin oxide. The transparent conductive material may include doped zinc oxide. The transparent conductive material may include carbon nanotubes. The transparent conductive material may include an amorphous material. The transparent conductive material may include a doped transparent semiconductor. The transparent conductive material may include a conductive polymer. The transparent conductive material may include a body including a transparent material and a coating of conductive material. The conductive material coating may comprise gold. The conductive material coating may comprise aluminum. The conductive material coating may comprise titanium. The conductive material coating may comprise chromium. The structure may comprise a substantially cylindrical column. The length of the portion of the column traversed by the electron beam may be selected to cause a predetermined amount of deceleration of electrons in the electron beam. The substantially cylindrical post may comprise an electrically conductive material. The conductive material may include gold. The conductive material may include silver. The electron beam may propagate along the central axis of the column. The radius of the substantially cylindrical column may decrease along the direction of propagation of the electron beam. The size or pitch of the absorbing structure may vary along the direction in which the electron beam propagates.

According to another aspect of the embodiments, an apparatus for generating a substantially monochromatic electron beam is disclosed, the apparatus comprising a first aperture arranged to block a portion of the electron beam to produce a modified electron beam; at least one electromagnetic focusing lens arranged to focus the modified electron beam to produce a collimated electron beam; a second aperture arranged to block a portion of the collimated electron beam to produce a modified collimated electron beam; a passive monochromator comprising a metamaterial absorber arranged to interact with the modified collimated electron beam to narrow the energy spread of the electron beam; and an objective lens arranged to focus the electron beam from the passive monochromator. The passive monochromator can include a structure defining a cavity having an interior surface and a metamaterial absorber disposed on the interior surface. The metamaterial absorber may include a layer of dielectric material on at least a portion of the interior surface, wherein the layer of transparent conductive material may be provided with a plurality of absorbing structures. The metamaterial absorber may include a transparent conductive material layer on at least a portion of the interior surface, wherein the transparent conductive material layer may be provided with a plurality of absorbing structures. The absorbent structure may be a metamaterial perfect absorber. The absorbing structure may be a plasma structure. The absorbing structure may be configured to resonantly absorb electromagnetic energy. The absorbent structure may be at least partially embedded in the layer of transparent conductive material. The absorbing structure may be made on top of a layer of transparent conductive material. The absorbent structure may be printed on the layer of transparent conductive material. The absorbent structure may comprise a plurality of mass elements comprising a metallic material. The absorbent structure may comprise graphene. The absorbent structure may comprise a plurality of graphene sheets. The absorbent structure may comprise a combination of a plurality of bulk metal elements and a plurality of graphene sheets. The absorbent structures may be arranged in a periodic array. The pitch of the periodic array may be selected to achieve maximum absorption of energy from the electron beam. The transparent conductive material may include indium tin oxide. The transparent conductive material may include doped zinc oxide. The transparent conductive material may include carbon nanotubes. The transparent conductive material may include an amorphous material. The transparent conductive material may include a doped transparent semiconductor. The transparent conductive material may include a conductive polymer. The transparent conductive material may include a body including a transparent material and a coating of conductive material. The conductive material coating may comprise gold. The conductive material coating may comprise aluminum. The conductive material coating may comprise titanium. The conductive material coating may comprise chromium. The structure may comprise a substantially cylindrical column. The length of the portion of the column traversed by the electron beam may be selected to cause a predetermined amount of deceleration of the electrons in the electron beam. The substantially cylindrical post may comprise an electrically conductive material. The conductive material may include gold. The conductive material may include silver. The electron beam may propagate along the central axis of the column. The radius of the substantially cylindrical column may decrease along the direction of propagation of the electron beam. The size or pitch of the absorbing structure may vary along the direction in which the electron beam propagates.

According to another aspect of an embodiment, an apparatus for narrowing the energy spread of an electron beam is disclosed, the apparatus comprising a structure defining a cavity extending along a portion of a path of the electron beam, the cavity having an interior surface adapted to absorb energy from electrons in the electron beam to narrow the energy spread of the electron beam. The interior surface may include a metamaterial absorber. The metamaterial absorber may include a layer of dielectric material on at least a portion of the interior surface, wherein the layer of transparent conductive material may be provided with a plurality of absorbing structures. The metamaterial absorber may include a layer of transparent conductive material on at least a portion of the interior surface, wherein the layer of transparent conductive material may be provided with a plurality of absorbing structures. The absorbent structure may be a metamaterial perfect absorber. The absorbing structure may be a plasma structure. The absorbing structure may be configured to resonantly absorb electromagnetic energy. The absorbent structure may be at least partially embedded in the layer of transparent conductive material. The absorbing structure may be made on top of a layer of transparent conductive material. The absorbent structure may be printed on the layer of transparent conductive material. The absorbent structure may comprise a plurality of mass elements comprising a metallic material. The absorbent structure may comprise graphene. The absorbent structure may comprise a plurality of graphene sheets. The absorbent structure may comprise a combination of a plurality of bulk metal elements and a plurality of graphene sheets. The absorbent structures may be arranged in a periodic array. The pitch of the periodic array may be selected to achieve maximum absorption of energy from the electron beam. The transparent conductive material may include indium tin oxide. The transparent conductive material may include doped zinc oxide. The transparent conductive material may include carbon nanotubes. The transparent conductive material may include an amorphous material. The transparent conductive material may include a doped transparent semiconductor. The transparent conductive material may include a conductive polymer. The transparent conductive material may include a body including a transparent material and a coating of conductive material. The conductive material coating may comprise gold. The conductive material coating may comprise aluminum. The conductive material coating may comprise titanium. The conductive material coating may comprise chromium. The structure may comprise a substantially cylindrical column. The length of the portion of the column traversed by the electron beam may be selected to cause a predetermined amount of deceleration of the electrons in the electron beam. The substantially cylindrical post may comprise an electrically conductive material. The conductive material may include gold. The conductive material may include silver. The electron beam may propagate along the central axis of the column. The radius of the substantially cylindrical column may decrease in the direction of propagation of the electron beam. The size or pitch of the absorbing structure may vary along the direction in which the electron beam propagates.

According to another aspect of the embodiments, a method of reducing a width of an energy distribution in an electron beam is disclosed, the method comprising the steps of: the beam is passed through a volume of space defined by structures extending along the path of the beam, the surface being provided with a metamaterial absorber arranged to absorb energy from the electrons. The metamaterial absorber may include a transparent conductive material layer on at least a portion of the interior surface, wherein the transparent conductive material layer may be provided with a plurality of absorbing structures. The metamaterial absorber may include a layer of dielectric material on at least a portion of the interior surface, wherein the layer of transparent conductive material may be provided with a plurality of absorbing structures. The metamaterial absorber may include a transparent conductive material layer on at least a portion of the interior surface, wherein the transparent conductive material layer may be provided with a plurality of absorbing structures. The absorbent structure may be a metamaterial perfect absorber. The absorbing structure may be a plasma structure. The absorbing structure may be configured to resonantly absorb electromagnetic energy. The absorbent structure may be at least partially embedded in the layer of transparent conductive material. The absorbing structure may be made on top of a layer of transparent conductive material. The absorbent structure may be printed on the layer of transparent conductive material. The absorbent structure may comprise a plurality of mass elements comprising a metallic material. The absorbent structure may comprise graphene. The absorbent structure may comprise a plurality of graphene sheets. The absorbent structure may comprise a combination of a plurality of bulk metal elements and a plurality of graphene sheets. The absorbent structures may be arranged in a periodic array. The pitch of the periodic array may be selected to achieve maximum absorption of energy from the electron beam. The transparent conductive material may include indium tin oxide. The transparent conductive material may include doped zinc oxide. The transparent conductive material may include carbon nanotubes. The transparent conductive material may include an amorphous material. The transparent conductive material may include a doped transparent semiconductor. The transparent conductive material may include a conductive polymer. The transparent conductive material may include a body including a transparent material and a coating of conductive material. The conductive material coating may comprise gold. The conductive material coating may comprise aluminum. The conductive material coating may comprise titanium. The conductive material coating may comprise chromium. The structure may comprise a substantially cylindrical column. The length of the portion of the column traversed by the electron beam may be selected to cause a predetermined amount of deceleration of the electrons in the electron beam. The substantially cylindrical post may comprise an electrically conductive material. The conductive material may include gold. The conductive material may include silver. The electron beam may propagate along the central axis of the column. The radius of the substantially cylindrical column may decrease along the direction of propagation of the electron beam. The size or pitch of the absorbing structure may vary along the direction in which the electron beam propagates.

Further features and advantages of the invention, as well as the structure and operation of various embodiments of the invention, are described in detail below with reference to the accompanying drawings. It should be noted that the present invention is not limited to the specific embodiments described herein. Such embodiments are presented herein for illustrative purposes only. Additional embodiments will be apparent to persons skilled in the relevant art(s) based on the teachings contained herein.

Drawings

The accompanying drawings, which are incorporated herein and form a part of the specification, illustrate the present invention and, together with the description, further serve to explain the principles of the invention and to enable a person skilled in the pertinent art to make and use the invention.

Fig. 1 is a schematic diagram illustrating an exemplary electron beam inspection system consistent with some embodiments of the present disclosure.

Fig. 2 is a schematic diagram illustrating additional aspects of an exemplary electron beam inspection system consistent with some embodiments of the present disclosure.

Fig. 3 is a side view illustrating additional aspects of an exemplary electron beam inspection system consistent with some embodiments of the present disclosure.

FIG. 4A is a partial perspective view of a monochromator, such as may be used in the system of FIG. 3; fig. 4B is a cross-section of fig. 4A taken along line B-B.

FIG. 5 is a partial perspective view of a monochromator, such as may be used in the system of FIG. 1.

FIG. 6 is a cross-sectional view of the monochromator of FIG. 4A.

Fig. 7 is a plan view of a metamaterial absorber in accordance with an aspect of an embodiment.

Fig. 8 is a plan view of a metamaterial absorber in accordance with an aspect of an embodiment.

Fig. 9 is a flow diagram illustrating exemplary steps in a method in accordance with an aspect of an embodiment.

Fig. 10A illustrates an exemplary electron beam tool that may be part of the charged particle inspection system of fig. 1, consistent with some embodiments of the present disclosure.

FIG. 10B is a schematic diagram illustrating the operation of a programmable pixelated mirror plate and voltage control consistent with some embodiments of the present disclosure.

FIG. 10C is another schematic diagram illustrating the operation of a programmable pixelated mirror plate and voltage control for correcting different aberrations for different beamlets in a multi-beam system consistent with some embodiments of the present disclosure.

Fig. 10D is a flow chart illustrating an exemplary method of correcting aberrations of a beamlet consistent with some embodiments of the present disclosure.

Fig. 11 illustrates an exemplary electron beam tool that may be part of the charged particle inspection system of fig. 1, consistent with some embodiments of the present disclosure.

Fig. 12A is a schematic plan view of the absorbent structure of fig. 11, consistent with some embodiments of the present disclosure.

Fig. 12B is a cross-sectional view of the absorbent structure of fig. 11, consistent with some embodiments of the present disclosure.

FIG. 13 is a schematic diagram illustrating the operation of a cascaded configuration of absorbing structures and programmable pixelated mirror plates consistent with some embodiments of the present disclosure.

FIG. 14 is a schematic diagram illustrating the operation of a combined construction of an absorbing structure and a programmable pixelated mirror plate consistent with some embodiments of the present disclosure.

Fig. 15 is a flow chart illustrating an exemplary method of correcting aberrations and energy spread of a beamlet consistent with some embodiments of the present disclosure.

Fig. 16 is a flow chart illustrating another exemplary method of correcting aberrations and energy spread of a beamlet consistent with some embodiments of the present disclosure.

Detailed Description

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

Electronic devices are made up of circuits formed on a silicon wafer called a substrate. Many circuits may be formed together on the same silicon die and are referred to as integrated circuits or ICs. The size of these circuits has been significantly reduced so that more circuits can be fitted on the substrate. For example, an IC chip in a smartphone may be as small as a nail cover, but may contain over 20 billion transistors, each of which is less than 1/1000 to human hair.

The fabrication of these extremely small ICs is a complex, time consuming and expensive process, typically involving hundreds of individual steps. Even one-step errors can cause defects in the finished product, making it unusable. It is therefore an object of the manufacturing process to avoid such defects to maximize the number of functional ICs manufactured in the process, that is, to improve the overall yield of the process.

One component that improves yield is monitoring the chip manufacturing process to ensure that it is producing a sufficient number of functional integrated circuits. One way of 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 "picture" of the structure. The image may be used to determine whether the structure is formed correctly and whether it is formed in the correct location. If the structure has a defect, the process can be adjusted so that the defect is less likely to reoccur.

As the name implies, an SEM uses an electron beam because such a beam can be used to observe structures that are too small to be seen by an optical microscope (that is, a microscope using light). The electrons in one or more of the electron beams do not all have exactly the same energy. Instead, a spread of energy occurs, sometimes referred to as Δ E. However, when obtaining SEM images, it is desirable to use electrons with energies as close as possible. In other words, it is desirable to make Δ E as small as possible. A beam in which all electrons have almost the same energy is called monochromatic. Also, a device that spreads the energy of the beam less is called a monochromator.

Monochromators generally separate electrons having different energies and use slits to select electrons having the correct energy and block other electrons, that is, slits allow electrons having the desired energy to pass while blocking electrons not having the correct energy. In such monochromators, electrons having different energies are separated and discarded, and only a small fraction of the electrons having the desired energy is selected, thereby producing an electron beam comprising only a small fraction of the generated electrons. Thus, the cost of increasing imaging resolution using such monochromators is the loss of a large fraction of the electrons in the electron beam, resulting in a reduction in throughput of the SEM. One way to solve this problem is to retain all electrons but slow down some of them so that they all have approximately the same energy. Typically, this requires passing the electrons through different electric fields, which adds complexity. It may be advantageous to be able to use a device that passively reduces the energy of the electrons (that is, without having to apply an external electric field) to decelerate the faster electrons, thereby matching the velocity of the electrons.

The design of a typical monochromator may introduce obstacles in achieving monochromatic electrons. For example, if the diameter of the monochromator is large, the physical process responsible for reducing energy spread becomes weak, requiring a longer column of the SEM to manipulate the beam as it propagates through the column. On the other hand, if the diameter is reduced to enhance the physical effect, transmission loss or diffraction effect may be caused. Moreover, fabricating monochromators within the interior walls of the SEM column can be challenging and constrains alternatives to absorbing structures on the interior walls of the SEM.

In some embodiments of the disclosure, a system is provided that includes an absorber that efficiently draws away electron energy so that the electrons eventually all have about the same amount of energy. Of course, this is a simple description and the actual details are set forth more fully and more accurately below. In some embodiments of such systems, the absorber may be disposed on an interior surface of a cylinder through which electrons pass to form an electron beam. To facilitate the absorption of energy by the absorber from the too high energy electrons, the electrons need to pass close enough to the absorber, which presents a challenge to the design of the cylinder, as the cylinder may need to have a small enough diameter so that substantially all of the electrons can pass within a certain small distance of the absorber.

In other embodiments, to facilitate bringing the electrons sufficiently close to the absorber, the electrons can be directed to the mirror plate and the absorber can be mounted on the mirror plate. The mirror plate can be a programmable mirror plate that is configured to correct for aberrations in one or more electron beams. Each pixel in the mirror plate is connected to a voltage configured to cause the mirror plate to generate an electric field configured to correct aberrations of the beam. When the electrons of the beam approach the mirror plate, they also approach the absorber mounted on the mirror plate. The electric field generated by the mirror plate repels electrons in a manner that corrects for aberrations. Further, the electrons pass sufficiently close to the absorber before being reflected, such that the desired energy absorption by the absorber occurs, with the result that substantially all of the reflected electrons have similar energy.

In order to enhance the performance of the SEM system, it is desirable to correct aberrations without reducing the beam current and without inhibiting the operational flexibility of the SEM system. For example, it may be desirable to maintain a wide range of adjustability of SEM system parameters, such as primary beam energy, beam opening angle, and energy of secondary electrons reaching the detector.

Without limiting the scope of the present disclosure, the description and drawings of the embodiments may be exemplarily referred to using electron beams. However, the embodiments are not intended to limit the invention to specific charged particles. For example, the systems and methods for beam forming can be applied to photons, x-rays, ions, and the like. Still further, the term "beam" may refer to a primary electron beam, a primary electron sub-beam, a secondary electron sub-beam, or the like.

As used herein, unless expressly stated otherwise, the term "or" encompasses all possible combinations, except where not feasible. For example, if it is stated that a component may include a or B, the component may include a or B, or a and B, unless explicitly stated otherwise or otherwise not feasible. As a second example, if it is stated that a component may contain A, B or C, the component may 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 otherwise stated or not feasible.

In the description and claims, the terms "upward," "downward," "top," "bottom," "vertical," "horizontal," and the like may be used. Unless otherwise specified, these terms are intended to show only relative orientations, and not any absolute orientations, such as orientations relative to gravity. Also, terms such as left, right, front, rear, and the like are intended to give relative orientations only.

Referring now to fig. 1, an exemplary Electron Beam Inspection (EBI) system 10 consistent with some embodiments of the present disclosure is illustrated. As shown in fig. 1, the EBI system 10 includes a main chamber 11, a loading/locking chamber 20, an electron beam tool 100, and an Equipment Front End Module (EFEM) 30. The electron beam tool 100 is located within the main chamber 11.

The EFEM 30 includes a first load port 30a and a second load port 30 b. The EFEM 30 may include one or more additional load ports. The first and second load ports 30a and 30b may, for example, receive a wafer Front Opening Unified Pod (FOUP) containing a wafer (e.g., a semiconductor wafer or a wafer made of one or more other materials) or a sample to be inspected (the wafer and sample may be collectively referred to as "wafer" below). One or more robotic arms (not shown) in the EFEM 30 may transfer the wafer to the loading/locking chamber 20.

The loading/lock chamber 20 is connected to a loading/lock vacuum pump system (not shown) that removes gas molecules in the loading/lock chamber 20 to a first pressure below atmospheric pressure. After the first pressure is reached, one or more robotic arms (not shown) may transport the wafer from the loading/locking chamber 20 to the main chamber 11. The main chamber 11 is connected to a main chamber vacuum pumping system (not shown) that removes gas molecules in the main chamber 11 to reach a second pressure lower than the first pressure. After the second pressure is reached, the wafer is inspected by the electron beam tool 100. The e-beam tool 100 may be a single beam system, a multiple beam system, or a multiple column system, or a combination of these. The controller 19 is electronically connected to the e-beam tool 100. While the controller 19 is shown in FIG. 1 as being external to the structure including the primary chamber 11, the loading/locking chamber 20 and the EFEM 30, it should be appreciated that the controller 19 may be part of the structure.

Although the present disclosure provides an example of a main chamber 11 housing an electron beam inspection system, 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 system. Rather, it should be appreciated that the principles discussed herein may also be applied to other tools operating at a second pressure.

Fig. 2 illustrates an exemplary e-beam tool 100A that may be part of the EBI system of fig. 1. The electron beam tool 100A (also referred to herein as "apparatus 100A") includes an electron source 101, a gun aperture plate 171, a condenser lens 110, a source conversion unit 120, a primary projection optical system 130, a secondary imaging system 150, and an electron detection device 140M. The primary projection optical system 130 may include an objective lens 131. The sample 1 with the sample surface 7 may be provided on a movable stage (not shown). The electronic detection device 140M may include a plurality of detection elements 140_1, 140_2, and 140_ 3. The beam splitter 160 and the deflection scanning unit 132 may be disposed inside the primary projection optical system 130.

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

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

The source conversion unit 120 may include an image forming element array (not shown in fig. 2) and a beam limiting aperture array (not shown in fig. 2). In some embodiments, the array of image forming elements may comprise a plurality of micro-deflectors or micro-lenses which may influence the plurality of primary beamlets 102_1, 102_2, 102_3 of the primary electron beam 102 and form a plurality of parallel images (virtual or real) of the primary beam crossings 101s, one for each of the primary beamlets 102_1, 102_2, 102_ 3. In some embodiments, the array of beam-limiting apertures may be configured to limit the diameter of the individual primary sub-beams 102_1, 102_2, and 102_ 3. Fig. 2 shows three primary beamlets 102_1, 102_2, and 102_3 as an example, and it should be appreciated that the source conversion unit 120 may be configured to form any number of primary beamlets. For example, the source conversion unit 120 may be configured to form a 3 × 3 array of primary beamlets. The source conversion unit 120 may further include an aberration compensator array configured to compensate for aberrations of the probe spots 102_1S, 102_2S, and 102_ 3S. In some embodiments, the aberration compensator array may include a curvature of field compensator array having microlenses configured to compensate for curvature of field aberrations of the probe spots 102_1S, 102_2S, and 102_3S, respectively. In some embodiments, the aberration compensator array can include a stigmator array having micro-stigmators configured to compensate for astigmatic aberrations of the probe spots 102_1S, 102_2S, and 102_3S, respectively. In some embodiments, the image forming element array, the field curvature compensator array, and the astigmatism compensator array may include multiple layers of micro-deflectors, micro-lenses, and micro-stigmators, respectively.

The converging lens 110 is configured to focus the primary electron beam 102. The converging lens 110 may also be configured to adjust the current of the primary beamlets 102_1, 102_2, and 102_3 downstream of the source conversion unit 120 by varying the power of the converging lens 110. The beamlets 102_1, 102_2, and 102_3 may thus have a focus state that may be changed by the converging lens 110. Alternatively, the current may be varied by altering the radial dimensions of the beam-limiting apertures within the array of beam-limiting apertures corresponding to the individual sub-beams. Thus, the current of the beamlets may be different at different positions along the trajectory of the beamlets. The beamlet current may be adjusted so that the beamlet current (e.g., probe spot current) on the sample surface is set to a desired amount.

The converging lens 110 may be a movable converging lens, which may be configured such that the position of its first main plane is movable. The movable condenser lens may be configured as a magnetic condenser lens, or an electrostatic condenser lens, or an electromagnetic condenser lens (e.g., a compound condenser lens). Movable converging lenses are also described in U.S. patent No. 9,922,799 and U.S. patent application publication 2017/0025243, both of which are incorporated herein in their entirety. In some embodiments, the converging lens may be an anti-rotation lens that may maintain the rotation angle of the off-axis beamlets constant while varying the beamlet current. In some embodiments, the converging lens 110 may be a movable anti-rotation converging lens comprising an anti-rotation lens having a movable first major plane. Anti-rotational or movable anti-rotational converging lenses are also described in international application number PCT/EP2017/084429, which is incorporated by reference in its entirety.

The objective 131 may be configured to focus the beamlets 102_1, 102_2, and 102_3 onto the sample 190 for inspection and may form three probe spots 102_1S, 102_2S, and 102_3S on the surface 7 in the current embodiment. In operation, the gun aperture plate 171 is configured to block peripheral electrons of the primary electron beam 102 to reduce coulomb interaction effects. The coulomb interaction effect may enlarge the size of each of the probe spots 102_1S, 102_2S, and 102_3S of the primary beamlets 102_1, 102_2, 102_3, thereby reducing inspection resolution. A beam monochromator 165 is also shown, as described in more detail below.

In operation, the deflecting scanning unit 132 is configured to deflect the primary beamlets 102_1, 102_2, and 102_3 to scan the probe spots 102_1S, 102_2S, and 102_3S across individual scanning areas in a segment of the surface 7. In response to irradiation of the sample 190 by the primary beamlets 102_1, 102_2 and 102_3 at the probe spots 102_1S, 102_2S and 102_3S, secondary electrons are ejected from the sample 1 and form three secondary electron beams 102_1se, 102_2se and 102_3se, which in operation, three secondary electron beams 102_1se, 102_2se and 102_3se are emitted from the sample 1. Each of the secondary electron beams 102_1se, 102_2se, and 102_3se typically includes electrons having different energies, including secondary electrons (having an electron energy ≦ 50 eV) and backscattered electrons (having an electron energy between 50eV and the landing energy of the primary beamlets 102_1, 102_2, and 102_ 3). The secondary imaging system 150 then focuses the secondary electron beams 102_1se, 102_2se, and 102_3se onto the detection elements 140_1, 140_2, and 140_3 of the electron detection device 140M. The detection elements 140_1, 140_2 and 140_3 are arranged to detect the corresponding secondary electron beams 102_1se, 102_2se and 102_3se and to generate corresponding signals that can be sent to a signal processing unit (not shown), e.g. to construct an image of the corresponding scanned area of the sample 1.

Fig. 3 illustrates an arrangement in accordance with an aspect of an embodiment. In such a system, the electron source 101 is used to generate a large number of electrons 101 s. The holes 171 serve to remove unwanted electrons so that coulomb interactions are well mitigated. This produces a beam 102. Converging lenses 110 and 112 collimate electron beam 102. Converging lenses 110 and 112 may be used with aperture 300 to vary the beam current. A passive monochromator 310 (to be used as monochromator 165 in fig. 2, for example) is disposed below (i.e., downstream of) aperture 300. The function of the passive monochromator 310 is to reduce the energy spread of the electron beam 102. The objective lens 131 is then used to focus the electron beam 102 on the sample 1.

Fig. 4A is a partial perspective view of the passive monochromator 310 shown in fig. 3. As can be seen, passive monochromator 310 comprises a structure defining a cavity 312 (FIG. 4B) through which electron beam 102 passes. The cavity 312 may be hollow, or it may enclose a material that is transparent to light or electron beams. As shown, the structure may be substantially cylindrical and have a central axis that coincides with the path of the electron beam 102. As shown in fig. 4B, which is a cross-section of the arrangement of fig. 4A taken along line B-B, surrounding the cavity 312 is an absorbent structure layer 314, as described in more detail below. The absorbent structure layer 314 is disposed on a layer 316, which layer 316 comprises, for example, a dielectric material or a transparent conductive material. The transparent conductive material will conduct stray electrons on the strike layer 316 away from the device and avoid charging the walls. Dielectric materials may be used where stray electron flux is not expected to be significant, for example, if the beam is sufficiently collimated, or when charging may not be visible for a charged particle beam. Numeral 318 indicates the outer wall of the structure made of electrically conductive material. The conductive material may include, for example, gold or silver.

In the arrangement of fig. 4A, the exterior of the passive monochromator 310 is configured to be substantially cylindrical. However, for some applications, it may be beneficial to alter the radius of passive monochromator 310 according to a position on the beam axis such that passive monochromator 310 has a first radius where beam 102 enters passive monochromator 310 and a second radius where beam 102 exits passive monochromator 310. In the example shown in FIG. 5, perimeter R1 is greater than perimeter R2, such that the overall configuration of passive monochromator 310 is frustoconical. This configuration may allow passive monochromator 310 to more efficiently absorb energy from electrons in electron beam 102.

As mentioned above, the passive monochromator 310 may be implemented by embedding absorbing structures that absorb electromagnetic energy in a resonant manner at wavelengths determined by the materials of which they are composed and their geometric characteristics. Since the absorption efficiency is almost 100%, these structures are called plasmonic/metamaterial perfect absorbers. Note that these structures are referred to in the literature and in the present application as "perfect" absorbers, even though their absorption efficiency is below 100%.

Fig. 6 schematically shows a plane through the passive monochromator 310 with the absorbing structures 314 embedded or coupled to the inner walls. These absorbent structures 314 may take any of several forms, such as metal blocks, graphene sheets, or a combination of both, printed on top of a layer 316 disposed on a metal wall 318. Other configurations (such as graphene ribbons) are also known and are within the scope of the present disclosure.

Fig. 7 is a diagrammatic plan view of absorbing structures 314 embedded in or coupled to a layer, such as layer 316, which may be a transparent electrode. In the particular arrangement shown, the absorbent structure 314 is a graphene sheet, however, as stated above, other absorbent structures may be used. The absorbing structure 314 together with the layer 316 constitutes a so-called perfect absorber or metamaterial absorber, that is to say a material which is designed to absorb electromagnetic radiation efficiently. It should be seen that the absorbing structures 314 are embedded or coupled to the layer 316 in a periodic array having a pitch P. In addition to tuning the performance of the metamaterial absorber by selecting the geometry (shape and size) and material of the absorbent structure 314, the performance of the metamaterial absorber can also be tuned by altering the pitch P. For example, at the beginning of the column, the absorbing structure 314 may be selected to efficiently interact with high-energy electrons, and then in the column, the absorbing structure 314 may be selected and configured to more efficiently decelerate low-energy electrons. Fig. 8 shows a metamaterial absorber implemented as an array of metal blocks 314. The blocks vary in shape and pitch in the direction of propagation of the electron beam e.

As discussed above, it is desirable in some applications to use a transparent electrode that acts as a dielectric with respect to electromagnetic radiation but conducts electrical charges. The transparent conductive electrode may be, for example, indium tin oxide, doped zinc oxide, carbon nanotubes, amorphous materials, doped transparent semiconductors, or conductive polymers. The transparent conductive electrode may for example be a transparent material and the coating of a conductive material with a coating, for example gold, aluminum, titanium or chromium.

The deceleration of the electrons is a function of the electron velocity or energy. High-energy electrons interact strongly with electromagnetic modes at specific frequencies compared to low-energy electrons. As a result, high-energy electrons may also be decelerated more than low-energy electrons. Once the electrons are sufficiently decelerated, their interaction with the absorber becomes so weak that the electrons no longer exhibit any significant energy shift. Thus, the output electron beam will have electrons of substantially the same energy. Additionally, the length of the portion of the monochromator traversed by the electron beam may also be chosen so as to cause only a pre-selected determined amount of deceleration of the incident electrons.

Although the above arrangement is described in connection with its use as a monochromator, it may equally be useful to down-convert the energy of the electron beam in a passive manner without applying a retarding potential.

In general, there are many candidates for a metamaterial absorbent structure, each with its own advantages. In practice, the design constraints imposed by a particular application dictate the selection of the best candidate. For example, according to one aspect of an embodiment, it may be desirable to decelerate the electrons by absorption in the optical or terahertz bands. The metamaterial absorber structure may take the form of graphene microstrips, possibly even planar films.

According to another aspect of the embodiments, a method of reducing energy spread of an electron beam using a metamaterial absorber is disclosed. Referring to fig. 9, in a first step S10, an electron beam is generated. Then, in step S20, the electron beam is "cut out", that is, passed through the hole. In step S30, the energy spread of the electron beam is reduced using a monochromator having a metamaterial absorber. In step S40, the electron beam, which is substantially monochromatic at this time, is focused, typically using an objective lens. In step S50, the focused electron beam is caused to impinge on the sample to irradiate the sample with the electron beam.

Fig. 10A illustrates an exemplary electron beam tool 100B consistent with some embodiments of the present disclosure, which exemplary electron beam tool 100B may be part of the charged particle inspection system of fig. 1. The electron beam tool 100B (also referred to herein as the apparatus 100B) includes an electron source 101, a first lens 1010, a second lens 1031, a beam splitter 1060, a programmable charged particle mirror plate 1000, and a voltage control 1050. For simplicity, other components that are typically present (such as apertures and deflectors) are not shown in fig. 10A. A sample 1011 having a sample surface 1012 may be disposed on a movable stage (not shown). The electron source 101, lens 1010, and lens 1031 may be aligned with the primary optical axis of the device 100B.

The electron source 101 may comprise a cathode (not shown) and an extractor or anode (not shown), wherein during operation the electron source 101 is configured to emit primary electrons from the cathode and the primary electrons are extracted or accelerated by the extractor or anode to form a primary electron beam, which is shown as a series of wave fronts, that is, one or more surfaces (real or virtual) whose oscillation phases are the same. It can be seen that the wavefront of the beam as emitted by the source 101 is shown as being substantially spherical.

The beam splitter 1060, mirror plate 1000, and voltage control 1050 are introduced to the beam path to correct for aberrations. The beam splitter 1060, mirror plate 1000, and voltage control 1050 are introduced between the lenses to pre-shape the wavefront so that the net effect of the pre-shaping and aberrations is a more properly focused beam. As described in more detail below, it should be understood that the placement of the beam splitter 1060, mirror plate 1000, and voltage control 1050 in the device 100B is merely an example, and that the beam splitter 1060, mirror plate 1000, and voltage control 1050 can be placed in other locations in the device 100B.

The beam splitter 1060 may be a Wien (Wien) filter type beam splitter that may generate an electrostatic dipole field and a magnetic dipole field. In some embodiments, the force exerted by the electrostatic dipole field on the electrons of the beamlets may be equal in magnitude and opposite in direction to the force exerted by the magnetic dipole field on the electrons. Thus, the beamlets may pass straight through the beam splitter 1060 at a zero deflection angle. However, the total dispersion of the beamlets generated by the beam splitter 1060 may also be non-zero. The beam splitter 1060 can direct the incoming sub-beam towards the mirror plate 1000 and also direct the beam reflected from the mirror plate 1000 into another direction. The mirror plate 1000 can correct aberrations of the incoming beamlets and reflect the corrected beamlets towards the beam splitter 1060.

Further, in the examples described below, the mirror plate 1000 is described primarily in terms of correcting aberrations produced by the lens. However, the mirror plate 1000 can also or alternatively be used to shape the charged particle beam. For example, the mirror plate 1000 can be used to make the beam cross-sectional profile annular rather than spot-like on the sample. This may provide advantages in certain applications, such as for imaging the sidewalls of the contact holes. As another example, the beam profile may be made to diverge less at the wafer to produce a greater depth of focus.

In some embodiments, the apparatus 100B can include additional optical elements (such as electrodes) paired with adjustable voltages, or magnetic optical elements paired with adjustable excitations placed between the mirror plate 1000 and the splitter 1060 to further influence the electric and magnetic fields to correct aberrations. A plurality of drivers may be coupled to the electrodes or the magneto-optical element, wherein each driver of the plurality of drivers may be configured to provide an adjustable voltage or an adjustable excitation to the corresponding electrode or the corresponding magneto-optical element, respectively. Additional optical elements coupled to the mirror plate 1000 can be used to correct for possible additional aberrations caused by the lens 1010 or the beam splitter 1060, such as aberrations caused by the multipole field. For example, in one example implementation, the mirror plate 1000 can be used to correct rotationally symmetric aberrations or asymmetric aberrations, while the additional optical element can be used to correct asymmetric aberrations caused by the multipole field.

The mirror plate 1000 can reflect the sub-beams above the mirror surface by applying a negative total voltage or a positive total voltage on the mirror plate 1000. For example, the voltage control 1050 can apply a negative total voltage to the mirror plate 1000 to reflect electrons (or negative ions) from the sub-beams. In another example, the voltage control 1050 can apply a positive total voltage to the mirror plate 1000 to reflect positively charged particles (or positive ions) from the sub-beam. The beamlets are reflected towards a beam splitter 1060 where the reflected beamlets are directed into another direction and may be focused on the sample. Fig. 10A shows the beamlets bent at 90 degrees, and it will be appreciated that the beamlets may be bent at other angles. Moreover, the mirror plate 1000 can be further configured to reflect only one of the plurality of sub-beams.

In some embodiments, the mirror plate 1000 and the voltage control 1050 can be implemented in separate components. In some other embodiments, the mirror plate 1000 and the voltage control 1050 can be implemented in a single component.

In some implementations, a second mirror plate can be provided to reflect the sub-beams that have been reflected by mirror plate 1000 inside device 100B. For example, a sub-beam reflected from mirror plate 1000 can be directed to a second mirror plate implemented within device 100B (such as near beam splitter 1060). The second mirror plate may reflect the transmitted sub-beam from the beam splitter 1060 toward a second beam splitter, where the second beam splitter directs the reflected sub-beam into another direction and may be focused on the sample.

Reference is now made to FIG. 10B, which is a schematic illustration of the operation of a programmable pixelated mirror plate 1000 and voltage control 1050, consistent with some embodiments of the present invention. The mirror plate 1000 can include a set of pixels 1001-1007 to shape the profile of the sub-beams near the set of pixels. The voltage control 1050 may include a set of control members 1051-1057 associated with each pixel in the set of pixels 1001-1007, respectively. Each pixel control means 1051 to 1057 is arranged and configured to apply a signal (e.g. a voltage) to an associated pixel. Thus, the mirror plate 1000 is programmable in that voltages can be provided differently for each pixel or group of pixels and can be varied as desired. The voltage provided by each of the pixel control components 1051-1057 can generate a curved equipotential surface (custom electric field) 1090 above the mirror plate 1000. Equipotential surfaces 1090 can determine the locations of reflections of electrons from different parts of beamlet 1061 and this reflection affects the shape and phase of beamlet 1061r reflected by mirror plate 1000. Thus, adjustment of the voltage controls aberrations by adjusting the beamlet 1061 locally (i.e., one or more positions where the beamlet 1061 is affected by the equipotential surface 1090), and enables the reflected beamlet 1061r to obtain one or more desired characteristics, such as focusing a certain point on the sample at a desired resolution. While the mirror plate 1000 is arranged with seven pixels and corresponding seven control features, it will be appreciated that a different number of pixels and control features can be arranged, and the pixels or control features can be arranged in any of a variety of arrangements.

In some embodiments, pixels 1001-1007 and corresponding pixel control means 1051-1057 may each be implemented in separate components. In other embodiments, the pixels 1001 to 1007 and the corresponding pixel control means 1051 to 1057 may be implemented in a single component.

The pixels 1001 to 1007 may each include a rectangular shape. It will be apparent that the pixels may comprise other shapes, such as hexagons, annular segments, squares, other suitable shapes, or combinations of these. For example, the beamlets are typically rotationally symmetric, so using pixels shared as ring segments may provide the advantage of reducing the number of required voltage controls and pixels. By way of further example, more pixels may be implemented in the same area by using hexagonal pixels instead of square pixels.

In some embodiments, the size of the pixels or the shape of the pixels 1001-1007 can vary across the mirror plate 1000. For example, smaller pixels can be used in areas of the mirror plate 1000 that require more precise correction, which can provide more accuracy in correcting aberrations. The voltage control 1050 may provide a voltage to each of these corresponding smaller pixels to provide a more precise beam shape. In some embodiments, each of pixels 1001-1007 may be uniquely controlled. For example, the voltage control may provide, for example, a negative voltage to certain pixels to reflect negatively charged particles interacting with those pixels, and a positive voltage to other pixels to attract charged particles that may fall outside the preferred beam shape for this example.

In some implementations, the mirror plate 1000 can include larger pixels to make beam shaping easier to control and implement. For example, larger pixels may each cover a larger area than smaller pixels, and may provide similar effects (e.g., such as reflection or attraction) on the incoming beamlets. In some implementations, the mirror plate 1000 can include larger pixels that can be used in portions of the mirror plate that are expected to reflect the sub-beam in unison and smaller pixels that can be used in portions of the mirror plate that may be on the periphery of locations where the sub-beam is expected to interact with in order to better control the beam shape.

In some embodiments, the mirror plate 1000 can be a curved mirror plate. When the mirror plate 1000 is curved, the voltage for correcting the aberration can be reduced. The mirror curvature can be mechanically adjusted and controlled by mechanical actuators, such as piezoelectric motors.

In some embodiments, individual pixels implemented in the mirror plate 1000 can be tilted by using individual pixels with mechanically tiltable upper surfaces. The tiltable pixels can be mechanically adjusted and controlled by mechanical actuators, such as piezoelectric motors. The tilted pixel can remove charged particles from the incoming beamlet, and the removed charged particles can scatter between the mirror plate 1000 and the beam splitter. The tilted pixels can create different paths for the charged particles, where the different paths can be used to filter out the charged particles from the incoming beamlets through beam apertures between the mirror plate 1000 and the beam splitter or elsewhere in the charged particle beam system.

During use, the focused electron beam is scanned over the surface of the sample. During scanning of a focused electron beam over a large field of view, the shape and intensity distribution (e.g., spot profile) of the image of the source over the surface of the sample may change. The use of the programmable mirror plate 1000 can correct or reduce these scanning effects by dynamically configuring the programmable mirror plate 1000. As stated above, the programmable mirror plate 1000 can be configured as a plate with pixels 1001-1007 each having individual voltage controls 1051-1057. The phase of the electron wave may be locally changed using a voltage control 1050 for adjusting the voltage at the pixel, where the voltage control 1050 may provide an AC voltage to the pixel to generate a time-dependent beam shape by variably reflecting the incoming sub-beam. For example, the portion of the electron wave reflected above the pixel may enable or facilitate control of the formation of the electron spot (probe). As a specific example, synchronizing mirror plate voltages with the scanning of the electron beam over the sample enables or facilitates dynamic control of probe formation over the entire scan field. In another example, when scanning a large field of view over a sample, more aberrations may occur at the outer edges of the beamlets compared to the center. By applying an AC voltage to the mirror plate 1000, the aberration of the outer edge of the sub-beam can be corrected more accurately.

In some embodiments, the mirror plate 1000 can provide different pixel voltage distributions in different directions on the surface of the mirror plate 1000. The beam splitter 1060 may add aberrations to the beamlets, and the aberrations may be non-rotationally symmetric because the beamlets are deflected in one direction. Thus, the sub-beams are losing the rotationally symmetric beam shape and the mirror plate can use different pixel voltage distributions in two different directions in order to correct the shape.

Reference is now made to FIG. 10C, which is another schematic illustration of the operation of the programmable pixelated mirror plate 1100 and the voltage control 1150 for correcting different aberrations of different beamlets in a multi-beam system, consistent with some embodiments of the present invention. The mirror plate 1100 can include three sets of pixels 1101-1105, 1111-1115 and 1121-1125, and the voltage control 1150 can include three sets of control components 1151-1155, 1161-1165 and 1171-1175 respectively associated with each pixel in the set of pixels. Each pixel control means 1151 to 1155, 1161 to 1165 and 1171 to 1175 is arranged and configured to apply a signal (e.g. a voltage) to the associated pixel. The voltage provided by each of the pixel control components 1151 to 1155, 1161 to 1165, and 1171 to 1175 can generate a corresponding three curved equipotential surfaces 1091 to 1093 (customized electric field) above the mirror plate 1100. The equipotential surfaces can determine the reflection locations of electrons from different parts of the three sub-beams and the reflection affects the shape and phase of each of the sub-beams reflected by the mirror plate 1100.

Each set of pixels implemented in mirror plate 1100 can also reflect a sub-beam at a different height above the surface of mirror plate 1100 by providing a different voltage to each set of pixels. Accordingly, the mirror plate 1100 may affect the shape and phase of each of the plurality of sub-beams and reflect the affected sub-beams at different angles toward the beam splitter to enable the SEM to obtain one or more desired characteristics, such as focusing at different points on the sample with a desired resolution for each of the sub-beams. Also, the mirror plate 1100 can locally control the amplitude of the electron wave in addition to or instead of controlling the phase by locally removing charged particles from portions of the incoming beamlets. The mirror plate 1100 can achieve control over the amplitude by preventing charged particles in the beamlets from reflecting toward the beam splitter (e.g., by attracting charged particles to the pixels rather than reflecting the charged particles).

In some embodiments, mirror plate 1100 can locally remove electrons from the beamlets by using a positive voltage on the pixel. Positively charged pixels can attract electrons above the pixel towards the mirror plate 1100 and absorb or scatter electrons on the surface of the mirror plate 1100.

The mirror plate 1100 can also remove positively charged particles in the sub-beam by using a negative voltage on the pixel. Scattered particles or secondary electrons originating from the mirror plate 1100 can have different paths between the mirror plate 1100 and the beam splitter and can be filtered out by placing the beam aperture in the appropriate position between the mirror plate 1100 and the beam splitter or elsewhere in the charged particle beam system.

The voltage distribution across the pixels may be different for each set of pixels assigned to a particular beamlet or each mirror plate. In some embodiments, the voltage distribution may be the same for certain sets of pixels or mirror plates to limit the number of individual voltage controls needed.

The voltage distribution across the pixel and the overall mirror plate voltage can be adjusted according to the landing energy of the beamlets to enable correction or reduction of aberrations at different electron beam system settings associated with different landing energies. The voltage distribution over the pixels can be adjusted according to the position of the beamlets on the sample. For example, the position of the beamlet may be a measure of whether the beamlet is off-axis or how far off-axis from the desired beam spot to optimize correction or reduction of aberrations at various off-axis positions of the beamlet.

The voltage distribution across the pixel and the overall mirror plate voltage can be adjusted according to the beam currents of the beamlets to enable correction or reduction of aberrations at different electron beam system settings associated with different beamlet currents. The voltage distribution across the pixel and the overall mirror plate voltage can be adjusted according to the landing angle of the sub-beam at the sample to enable correction or reduction of aberrations at different electron beam system settings associated with different landing angles.

The voltage distribution across the pixel and the overall mirror plate voltage can be adjusted according to the electric field at the sample to enable correction or reduction of aberrations at different electron beam system settings related to different electric fields at the sample.

Although the mirror plate 1100 of FIG. 10C is arranged with three pixel sets and associated three control members to correct for the aberrations of the three sub-beams, it will be appreciated that different numbers of pixel sets, control members, and sub-beams can be arranged in any of a variety of arrangements.

Reference is now made to fig. 10D, which is a flowchart of an exemplary method 1080 of correcting aberrations of the beamlets, consistent with some embodiments of the present disclosure. Method 1080 may be performed by an e-beam tool (e.g., e-beam tool 100B of fig. 10A). Moreover, while method 1080 describes correcting aberrations of the beamlets, it should be appreciated that method 1080 may also be applied to correct aberrations of a plurality of beamlets.

In step 1081, the beamlets are directed towards a programmable charged particle mirror plate (e.g., programmable charged particle mirror plate 1000 of FIG. 10A). For example, the beamlets may be directed by a beam splitter (e.g., beam splitter 1060 of fig. 10A). In some embodiments, a controller (e.g., controller 19 of FIG. 1) can instruct the beam splitter to direct the beamlets to the programmable charged particle mirror plates.

In step 1082, signals (e.g., voltages) are provided to the pixels of the programmable charged particle mirror plate (e.g., pixels 1001-1007 of FIG. 10B). In some embodiments, these signals may be provided by voltage controls (e.g., voltage controls 1050 of fig. 10A), where each pixel may have a corresponding voltage control (e.g., voltage controls 1051-1057 of fig. 10B). In some embodiments, the provided signal may be a negative voltage to reflect electrons (or negative ions) and attract positively charged particles from the sub-beam. In some embodiments, the provided signal may be a positive voltage to reflect positively charged particles (or positive ions) and attract electrons from the sub-beam.

The pixels may comprise a set of pixels for influencing the directed beamlets. For example, the set of pixels may be configured to shape the profile of the beamlets proximate the set of pixels. Each pixel in the set of pixels in the mirror plate can have a separate voltage control configured to establish a voltage in the pixel. The mirror plate is thus programmable in that the voltage can be provided to each pixel or set of pixels in different ways and can be changed as desired. The provided voltages may generate a tailored electric field (e.g., equipotential surface 1090 of fig. 10B) determined to shape the beamlet profile. Adjustment of the voltage may also change the phase of electrons included in the beamlets.

In step 1083, the shaped beamlets are reflected by the programmable charged particle mirror plates to reduce aberrations. The sub-beams are reflected over the surface of the mirror plate by voltages applied to pixels on the mirror plate.

In some embodiments, method 1080 may also include the following additional steps: the shaped beamlets are directed to a sample surface (e.g., sample surface 1012 of fig. 10A). Before reaching the sample surface, the shaped beamlets may also be affected by an objective lens (e.g., second lens 1031 of fig. 10A), which may be used to focus the shaped beamlets onto the sample surface.

Fig. 11 illustrates an exemplary electron beam tool 100C consistent with some embodiments of the present disclosure, which exemplary electron beam tool 100C may be part of the charged particle inspection system of fig. 1. The electron beam tool 100C (also referred to herein as the apparatus 100C) includes a beam splitter 1060B and an absorbing component 1200. For simplicity, other components that are typically present (such as apertures and deflectors) are not shown in fig. 1.

A beam splitter 1060B and an absorbing member 1200 are introduced into the beam path to reduce the energy spread of the charged particle beamlets. As described in more detail below, it should be understood that the placement of beam splitter 1060B and absorbing member 1200 in apparatus 100C is merely an example, and that beam splitter 1060B and absorbing member 1200 may be placed in other locations in device 100C. The beam splitter 1060B may operate similarly to the beam splitter 1060 in fig. 10A, may direct incoming beamlets toward the absorption member 1200, and may also direct beams reflected from the absorption member 1200 to another direction. The absorbing member 1200 can reduce the energy spread of the incoming beamlets and reflect the reduced beamlets toward the beam splitter 1060B.

The absorptive member 1200 may absorb electromagnetic energy at wavelengths determined by its constituent materials and their geometric characteristics. The high energy electrons of the incoming beamlet may interact more strongly with the electromagnetic mode at a particular frequency, penetrate more through the negative potential, and be closer to the absorbing member 1200 than the low energy electrons of the incoming beamlet. As the electrons get closer to the absorbing member 1200, the interaction between the electrons of the incoming beamlets and the absorbing member 1200 may become stronger, and the electrons may dissipate more energy to the electromagnetic radiation towards the absorbing member 1200 due to the interaction.

The absorptive member 1200 may be configured to be electrically biased to generate a negative potential over the absorptive member 1200 to reflect the incoming beamlets by connecting a voltage supply to the outer layer of the absorptive member 1200. Of course, this is a simple description and the actual details are set forth more fully and accurately in FIG. 12B below.

Fig. 12A is a schematic plan view of the absorbent member 1200. Absorbent component 1200 may include a collection of absorbent structures 1201 (which may be similar to absorbent structure 314 of fig. 6) and a layer 1202 (which may be similar to layer 316 of fig. 6). The absorbing structure 1201 may take any of a variety of forms, such as a metal block or graphene sheet, or the like, or a combination of such materials, embedded in or coupled to the layer 1202. By choosing the geometry (shape and size) and altering the pitch between the absorbing structures 1201, the absorbing member 1200 can be tuned to minimize or optimize the energy loss from the electrons depending on the landing energy and deceleration of the electrons.

Fig. 12B is a cross-sectional view of the absorbent member 1200. As described above with respect to fig. 12A, absorbent component 1200 may include a collection of absorbent structures 1201, layer 1202, and layer 1203 (which may be similar to layer 318 of fig. 6). As shown in fig. 12B, the absorbing structure 1201 is disposed on a layer 1202 comprising, for example, a dielectric material or a transparent conductive material. The transparent conductive material conducts stray electrons impinging on layer 1202 away from absorbing member 1200 and avoids charging absorbing member 1200. For example, layer 1202 can be indium tin oxide, doped zinc oxide, carbon nanotubes, amorphous materials, doped transparent semiconductors, or conductive polymers, among others. Layer 1202 may be disposed on layer 1203, which layer 1203 may be a conductive material such as, for example, gold or silver.

Absorbing member 1200 may be configured to be electrically biased by connecting a voltage supply to layer 1203 to generate a potential above absorbing member 1200 to reflect the incoming beamlets. In some embodiments, the voltage of absorbing structure 1201 and layer 1202 may be the same or substantially similar to layer 1203 and create an electric field on top of absorbing member 1200. Applying a sufficiently high negative or positive voltage on the absorptive member 1200 may reflect charged particles from a beam traveling toward the absorptive member 1200.

Absorbing member 1200 may include structures and layers (e.g., structure 1201 and layers 1202 and 1203) that provide functionality similar to that of the structures and layers (e.g., structure 314 and layers 316 and 318) shown in fig. 6-8, such that absorbing member 1200 may absorb energy from charged particles having energy above a certain threshold.

In some embodiments, the absorptive component 1200 may include other types of layers, such as multiple metal and dielectric layers.

FIG. 13 is a schematic diagram illustrating the operation of a cascaded configuration of absorbing components 1300 and programmable pixelated mirror plates 1301 consistent with some embodiments of the present disclosure. The cascade configuration may be implemented in an e-beam tool 100D (also referred to herein as apparatus 100D). The cascaded configuration may include first beam splitter 1360C, second beam splitter 1360D, absorptive component 1300, and mirror plate 1301. The operation of first beam splitter 1360C is similar to that of beam splitter 1060 in fig. 10A, and can direct incoming beamlets toward absorbing member 1300, and also direct reflected beams from absorbing member 1300 into another direction. In some embodiments, first beam splitter 1360C may direct an incoming beamlet to fall perpendicular to absorbing member 1300. The operation of the absorbing member 1300 may be similar to the operation of the absorbing member 1200 in fig. 11, and the incoming beamlets 102 may be manipulated by reducing the energy spread in the incoming beamlets and reflecting the manipulated beamlets. The operation of second beam splitter 1360D is also similar to that of beam splitter 1060 in FIG. 10A, and can direct an incoming sub-beam toward mirror plate 1301 and also direct a reflected beam from mirror plate 1301 into another direction.

The operation of the mirror plate 1301 can be similar to the operation of the mirror plate 1000 in FIGS. 10A-10C and corrects for aberrations of the incoming beamlets, where the aberrations may have been introduced by the absorbing component 1300. The mirror plate 1301 can also reflect the corrected sub-beams. Thus, the cascaded configuration may ensure that both aberrations and energy spread are corrected.

While the cascaded configuration of FIG. 13 is arranged such that the beamlets propagate through the absorbing component 1300 and then through the mirror plate 1301, it will be appreciated that the mirror plate and the absorbing structure may be arranged in any of a variety of arrangements (such as the mirror plate 1301 before the absorbing component 1300).

FIG. 14 is a schematic diagram illustrating the operation of a combined configuration of a collection of absorbing components 1400 and a programmable pixelated mirror plate 1401, consistent with some embodiments of the present disclosure. The combined configuration may be implemented in an E-beam tool 100E (also referred to herein as apparatus 100E). The combined configuration may include the beam splitter 1460, the collection of absorbing members 1400, and the mirror plate 1401. The operation of the beam splitter 1460, similar to the operation of the beam splitter 1060 in FIG. 10A, can direct an incoming beamlet toward a combined structure comprising the collection of absorbing components 1400 and the mirror plate 1401, and also direct a reflected beamlet from the combined structure into another direction.

One or more absorbing members 1400 can be embedded in or coupled to the top of the mirror plate 1401. For example, each pixel of the mirror plate 1401 can have a different absorbing member 1400, or a collection of pixels can have absorbing members 1400, or all pixels of the mirror plate can have absorbing members 1400. In some embodiments, different absorbing components can be implemented on each pixel of the mirror plate 1401. The mirror plate 1401 can replace a layer of the absorbing component 1400 (such as layer 1202 in FIG. 12B) or an outer layer of the absorbing component 1400 (such as layer 1203 in FIG. 12B). The operation of the absorbing member 1400 is similar to that of the absorbing member 1200 in fig. 11 and 12A-12B, and the incoming beamlets may be manipulated by reducing the energy spread in the incoming beamlets. The operation of mirror plate 1401 can be similar to the operation of mirror plate 1000 in FIG. 10A, mirror plate 1401 corrects for aberrations of the incoming sub-beams, and reflects the corrected sub-beams. The absorbing member 1400 and the mirror plate 1401 can operate simultaneously to ensure that both aberrations and energy spread are corrected. The electric field generated by the mirror plate 1401 can repel charged particles of the incoming beamlets to correct for aberrations, while the charged particles pass sufficiently close to the absorbing component 1400 before being reflected by the mirror plate 1401, so that the absorbing component can absorb the desired energy, with the result that substantially all of the reflected charged particles have similar energy.

Reference is now made to fig. 15, which is a flowchart illustrating an exemplary method 1500 of correcting aberrations and energy spread of a beamlet, consistent with some embodiments of the present disclosure. The method 1500 may be performed by an E-beam tool (e.g., the E-beam tool 100E of fig. 14). Also, while method 1500 describes correcting aberrations and energy spread of the beamlets, it should be appreciated that method 1500 may also be applied to correct aberrations and energy spread of a plurality of beamlets.

In step 1510, the beamlets are directed towards a combined structure comprising absorbing members (e.g., absorbing members 1400 of FIG. 14) and programmable charged particle mirror plates (e.g., programmable charged particle mirror plates 1401 of FIG. 14). For example, the beamlets may be directed by a beam splitter (e.g., beam splitter 1460 of fig. 14). Although the embodiment of FIG. 15 uses programmable mirror plates, it is to be appreciated that other types of mirror plates can be used. In some embodiments, a controller (e.g., controller 19 of fig. 1) may instruct the beam splitter to direct the beamlets to the combining structure.

In step 1520, a signal (e.g., a voltage) is provided to the pixels of the programmable charged particle mirror plate (e.g., pixels 1001-1007 of FIG. 10B). In some embodiments, these signals may be provided by voltage controls (e.g., voltage controls 1050 of fig. 10A), where each pixel may have a corresponding voltage control (e.g., voltage controls 1051-1057 of fig. 10B). In some embodiments, the provided signal may be a negative voltage to reflect electrons (or negative ions) and attract positively charged particles (if present) from the beamlet. In some embodiments, the provided signal may be a positive voltage to reflect positively charged particles (or positive ions) and attract electrons (if present) from the sub-beam.

The pixels may comprise a set of pixels for influencing the directed beamlets. For example, the set of pixels may be configured to shape the profile of the beamlets proximate the set of pixels. Each pixel in the set of pixels in the mirror plate can have a separate voltage control configured to establish a voltage in the pixel. Thus, the mirror plate is programmable in that the voltage can be provided to each pixel or set of pixels in a different manner and can be varied as desired. The provided voltages may generate a custom electric field (e.g., equipotential surface 1090 of fig. 10B) determined to shape the beamlet profile. The adjustment of the voltage may also change the phase of the electrons comprised in the sub-beam.

In step 1530, an absorbing member (e.g., absorbing member 1400 of fig. 14) can manipulate the beam directed from the beam splitter by reducing the energy spread of the directed beam using an absorbing structure (e.g., absorbing structure 1201 in fig. 12A and 12B).

The absorptive member may absorb electromagnetic energy at wavelengths determined by its constituent materials and their geometric characteristics. The high-energy electrons of the incoming beamlet may interact more strongly with the electromagnetic mode at a particular frequency than the low-energy electrons of the incoming beamlet. The strong interaction may enable the electrons to penetrate more negative potential and closer to the absorbing member. As the electrons get closer to the absorbing member, the interaction between the electrons of the incoming beamlet and the absorbing member may become stronger, and the electrons may dissipate more energy to the electromagnetic radiation towards the absorbing member due to the interaction.

In step 1540, the shaped and manipulated sub-beams are reflected by the programmable charged particle mirror plates and the absorbing component to reduce aberrations and energy spread. The sub-beams are reflected over the surface of the mirror plate by voltages applied to pixels on the mirror plate.

In some embodiments, the method 1500 may further include the additional steps of: the shaped and steered beamlets are directed to a sample surface (e.g., sample surface 1012 of fig. 10A). Before reaching the sample surface, the shaped and manipulated beamlets may also be affected by an objective lens (e.g., second lens 1031 of fig. 10A) that may be used to focus the shaped and manipulated beamlets onto the sample surface.

Reference is now made to fig. 16, which is a flow chart illustrating another exemplary method 1600 of correcting aberrations and energy spread of a beamlet, consistent with some embodiments of the present disclosure. Method 1600 may be performed by an e-beam tool (e.g., e-beam tool 100D of fig. 13). Moreover, while method 1600 describes correcting aberrations and energy spread of the beamlets, it will be appreciated that method 1600 may also be applied to correct aberrations and energy spread of a plurality of beamlets.

In step 1610, the beamlets are directed towards an absorbing member (e.g., absorbing member 1300 of fig. 13). For example, the beamlets may be directed by a first beam splitter (e.g., beam splitter 1360C of fig. 13). In some embodiments, a controller (e.g., controller 19 of fig. 1) may instruct the first beam splitter to direct the beamlets to the absorption components.

In step 1620, the absorbing component can manipulate the beam directed from the first beam splitter by reducing the energy spread of the directed beam using an absorbing structure (e.g., absorbing structure 1201 in fig. 12A and 12B).

The absorptive member may absorb electromagnetic energy at wavelengths determined by its constituent materials and their geometric characteristics. The high-energy electrons of the incoming beamlet may interact more strongly with the electromagnetic mode at a particular frequency than the low-energy electrons of the incoming beamlet. The strong interaction may enable the electrons to penetrate more negative potential and closer to the absorbing member. As the electrons get closer to the absorbing member, the interaction between the electrons of the incoming beamlet and the absorbing member may become stronger, and the electrons may dissipate more energy to the electromagnetic radiation towards the absorbing member due to the interaction.

In step 1630, the steered beamlets are reflected by the absorbing component to the first beam splitter. The absorbing member may be configured to be electrically biased to generate a negative or positive potential above the absorbing member to reflect the guided sub-beam.

In step 1640, the reflected beamlet from step 1630 is directed by the first beam splitter toward a second beam splitter (e.g., beam splitter 1360D of fig. 13). In some embodiments, a controller (e.g., controller 19 of fig. 1) may instruct the first beam splitter to direct the beamlets to the second beam splitter. Although the embodiments describe the use of a beam splitter, it will be appreciated that another optical element may be used to direct the sub-beams.

In step 1650, the directed beamlets from step 1640 are directed towards a programmable charged particle mirror plate (e.g., programmable charged particle mirror plate 1301 of FIG. 13). For example, the beamlets may be directed by a second beam splitter (e.g., beam splitter 1360D of fig. 13). Although the embodiment of FIG. 16 employs programmable mirror plates, it is to be appreciated that other types of mirror plates can be employed. In some embodiments, a controller (e.g., controller 19 of FIG. 1) can instruct the second beam splitter to direct the sub-beams to the mirror plate.

In step 1660, a signal (e.g., a voltage) is provided to the pixels of the programmable charged particle mirror plate (e.g., pixels 1001-1007 of FIG. 10B). In some embodiments, these signals may be provided through a voltage control (e.g., voltage control 1050 of fig. 10A), where each pixel may have a corresponding voltage control (e.g., voltage controls 1051-1057 of fig. 10B). In some embodiments, the provided signal may be a negative voltage to reflect electrons (or negative ions) and attract positively charged particles from the sub-beam. In some embodiments, the provided signal may be a positive voltage to reflect positively charged particles (or positive ions) and attract electrons from the sub-beam.

The pixels may comprise a set of pixels used to influence the guided beamlets that may have been distorted by the absorbing structure. For example, the set of pixels may be configured to shape the profile of the beamlets proximate the set of pixels. Each pixel in the set of pixels in the mirror plate can have a separate voltage control configured to establish a voltage in the pixel. Thus, the mirror plate is programmable in that the voltage can be provided to each pixel or set of pixels in a different manner and can be varied as desired. The provided voltages may generate a custom electric field (e.g., equipotential surface 1090 of fig. 10B) determined to shape the beamlet profile. The adjustment of the voltage may also change the phase of the electrons comprised in the sub-beam.

In step 1670, the shaped beamlets are reflected by the programmable charged particle mirror plates to reduce aberrations. The sub-beams are reflected over the mirror plate surface by voltages applied to pixels on the mirror plate.

In some embodiments, the method 1600 may further include the additional steps of: the shaped and steered beamlets are directed to a sample surface (e.g., sample surface 1012 of fig. 10A). Before reaching the sample surface, the shaped and manipulated beamlets may also be affected by an objective lens (e.g., second lens 1031 of fig. 10A) that may be used to focus the shaped and manipulated beamlets onto the sample surface.

In some embodiments, the controller may control the charged particle beam system. The controller may comprise a computer processor. The controller can instruct components of the charged particle beam system to perform various functions, such as controlling various drivers for manipulating one or more beamlets, controlling beam splitters for directing the beamlets, and controlling voltage controls and corresponding pixels of the programmable charged particle mirror plates. The controller may include a storage device such as a hard disk, a cloud storage device, a Random Access Memory (RAM), other types of computer readable memory, and the like as a storage medium. The controller may be in communication with the cloud storage. A non-transitory computer readable medium may be provided that stores instructions for the processor of the controller 19 to perform beamforming or other functions and methods consistent with the present disclosure. 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 CD-ROM, any other optical data storage medium, any physical medium with patterns of holes, a RAM, a PROM, and EPROM, a FLASH-EPROM, or any other FLASH memory, NVRAM, a cache, registers, any other memory chip or cartridge, and networked versions thereof.

The embodiments may also be described using the following clauses:

1. an apparatus for narrowing the energy spread of an electron beam, the apparatus comprising:

a structure defining a cavity extending along a portion of a path of the charged electron beam, the cavity having an interior surface; and

a metamaterial absorber disposed on the interior surface.

2. The device according to clause 1, wherein the metamaterial absorber comprises a layer of dielectric material on at least a portion of the interior surface, wherein the layer of transparent conductive material is provided with a plurality of absorbing structures.

3. The device according to clause 1, wherein the metamaterial absorber comprises a transparent conductive material layer on at least a portion of the inner surface, wherein the transparent conductive material layer is provided with a plurality of absorbing structures

4. The device of clause 3, wherein the absorbent structure is a metamaterial perfect absorber.

5. The apparatus of clause 3, wherein the absorbing structure is a plasma structure.

6. The apparatus of clause 3, wherein the absorbing structure absorbs the electromagnetic energy in a resonant manner.

7. The device of clause 3, wherein the absorbent structure is at least partially embedded or coupled to the layer of transparent conductive material.

8. The device according to clause 3, wherein the absorbing structure is made on top of the layer of transparent conductive material.

9. The device of clause 3, wherein the absorbent structure is printed on the layer of transparent conductive material.

10. The apparatus of clause 3, wherein the absorbent structure comprises a plurality of bulk elements comprising a metallic material.

11. The device of clause 3, wherein the absorbent structure comprises graphene.

12. The device of clause 3, wherein the absorbent structure comprises a plurality of graphene sheets.

13. The apparatus of clause 3, wherein the absorbent structure comprises a combination of a plurality of bulk metal elements and a plurality of graphene sheets.

14. The device of clause 3, wherein the absorbent structures are arranged in a periodic array.

15. The apparatus of clause 14, wherein the pitch of the periodic array is selected to achieve maximum absorption of energy from the electron beam.

16. The device of clause 3, wherein the transparent conductive material comprises indium tin oxide.

17. The device of clause 3, wherein the transparent conductive material comprises doped zinc oxide.

18. The device of clause 3, wherein the transparent conductive material comprises carbon nanotubes.

19. The device of clause 3, wherein the transparent conductive material comprises an amorphous material.

20. The device of clause 3, wherein the transparent conductive material comprises a doped transparent semiconductor.

21. The device of clause 3, wherein the transparent conductive material comprises a conductive polymer.

22. The device of clause 3, wherein the transparent conductive material comprises a body comprising a transparent material and a coating of conductive material.

23. The apparatus of clause 22, wherein the conductive material coating comprises gold.

24. The apparatus of clause 22, wherein the conductive material coating comprises aluminum.

25. The apparatus of clause 22, wherein the conductive material coating comprises titanium.

26. The device of clause 22, wherein the conductive material coating comprises chromium.

27. The apparatus of clause 1, wherein the structure comprises a substantially cylindrical column.

28. The apparatus of clause 27, wherein the length of the portion of the column traversed by the electron beam is selected to cause a predetermined amount of deceleration of the electrons in the electron beam.

29. The apparatus of clause 27, wherein the substantially cylindrical column comprises an electrically conductive material.

30. The apparatus of clause 29, wherein the conductive material comprises gold.

31. The device of clause 29, wherein the conductive material comprises silver.

32. The apparatus of clause 28, wherein the electron beam propagates along a central axis of the column.

33. The apparatus of clause 28, wherein the radius of the substantially cylindrical column decreases in the direction of electron beam propagation.

34. The apparatus of clause 3, wherein the size of the absorbing structure varies along the direction in which the electron beam propagates.

35. An apparatus for generating a substantially monochromatic electron beam, the apparatus comprising:

an electron beam source;

a monochromator comprising a metamaterial absorber arranged to interact with the electron beam to generate a substantially monochromatic electron beam; and

an objective lens arranged to focus the substantially monochromatic electron beam.

36. The apparatus of clause 35, wherein the monochromator comprises a structure defining a cavity, the cavity having an interior surface; and a metamaterial absorber disposed on the interior surface.

37. The device of clause 36, wherein the metamaterial absorber comprises a layer of transparent conductive material on at least a portion of the interior surface, wherein the layer of transparent conductive material is provided with a plurality of absorbent structures.

38. The device of clause 37, wherein the absorbent structure is a metamaterial perfect absorber.

39. The apparatus of clause 37, wherein the absorbing structure comprises a plasma absorber.

40. The apparatus of clause 37, wherein the absorbing structure resonantly absorbs electromagnetic energy.

41. The device of clause 37, wherein the absorbent structure is at least partially embedded or coupled to the layer of transparent conductive material.

42. The device of clause 37, wherein the absorbent structure is fabricated on top of the layer of transparent conductive material.

43. The device of clause 37, wherein the absorbent structure is printed on the layer of transparent conductive material.

44. The apparatus of clause 37, wherein the absorbent structure comprises a plurality of bulk elements comprising a metallic material.

45. The device of clause 37, wherein the absorbent structure comprises graphene.

46. The device of clause 37, wherein the absorbent structure comprises a plurality of graphene sheets.

47. The apparatus of clause 37, wherein the absorbent structure comprises a combination of a plurality of bulk metal elements and a plurality of graphene sheets.

48. The device of clause 37, wherein the absorbent structures are arranged in a periodic array.

49. The apparatus of clause 48, wherein the pitch of the periodic array is selected to achieve maximum absorption of energy from the electron beam.

50. The device of clause 37, wherein the transparent conductive material comprises indium tin oxide.

51. The device of clause 37, wherein the transparent conductive material comprises doped zinc oxide.

52. The apparatus of clause 37, wherein the transparent conductive material comprises carbon nanotubes.

53. The device of clause 37, wherein the transparent conductive material comprises an amorphous material.

54. The device of clause 37, wherein the transparent conductive material comprises a doped transparent semiconductor.

55. The device of clause 37, wherein the transparent conductive material comprises a conductive polymer.

56. The device of clause 37, wherein the transparent conductive material comprises a body comprising a transparent material and a coating of conductive material.

57. The apparatus of clause 56, wherein the conductive material coating comprises gold.

58. The apparatus of clause 56, wherein the conductive material coating comprises aluminum.

59. The apparatus of clause 56, wherein the conductive material coating comprises titanium.

60. The apparatus of clause 56, wherein the conductive material coating comprises chromium.

61. The apparatus of clause 36, wherein the structure comprises a post comprising a conductive material.

62. The apparatus of clause 61, wherein the conductive material comprises gold.

63. The device of clause 61, wherein the conductive material comprises silver.

64. The apparatus of clause 61, wherein the column is substantially cylindrical.

65. The apparatus of clause 61, wherein the length of the portion of the column traversed by the electron beam is selected to cause a predetermined amount of deceleration of the electrons in the electron beam.

66. The apparatus of clause 64, wherein the electron beam propagates along a central axis of the column.

67. The device of clause 66, wherein the radius of the pillar decreases in the direction of electron beam propagation.

68. The apparatus of clause 36, wherein the geometric characteristic of the absorbing structure varies along the direction of electron beam propagation.

69. An apparatus for generating a substantially monochromatic electron beam, the apparatus comprising:

a first aperture arranged to block a portion of the electron beam to produce a modified electron beam;

at least one electromagnetic condenser lens arranged to collimate the modified electron beam to produce a collimated electron beam;

a second aperture arranged to block a portion of the collimated electron beam to produce a modified collimated electron beam;

a passive monochromator comprising a metamaterial absorber arranged to interact with the modified collimated electron beam to narrow the energy spread of the electron beam; and

an objective lens arranged to focus the electron beam from the passive monochromator.

70. The apparatus of clause 69, wherein the passive monochromator comprises a structure defining a cavity having an interior surface and a metamaterial absorber disposed on the interior surface.

71. The device of clause 70, wherein the metamaterial absorber comprises a layer of transparent conductive material on at least a portion of the interior surface, wherein the layer of transparent conductive material is provided with a plurality of absorbent structures.

72. The apparatus of clause 71, wherein the absorbing structure comprises a plasma absorber.

73. The apparatus of clause 71, wherein the absorbing structure resonantly absorbs electromagnetic energy.

74. The device of clause 71, wherein the absorbent structure is at least partially embedded or coupled to the layer of transparent conductive material.

75. The device of clause 71, wherein the absorbent structure is fabricated on top of the layer of transparent conductive material.

76. The device of clause 71, wherein the absorbent structure is printed on the layer of transparent conductive material.

77. The apparatus of clause 71, wherein the absorbent structure comprises a plurality of mass elements comprising a metallic material.

78. The device of clause 71, wherein the absorbent structure comprises graphene.

79. The device of clause 71, wherein the absorbent structure comprises a plurality of graphene sheets.

80. The apparatus of clause 71, wherein the absorbent structure comprises a combination of a plurality of bulk metal elements and a plurality of graphene sheets.

81. The device of clause 71, wherein the absorbent structures are arranged in a periodic array.

82. The apparatus of clause 81, wherein the pitch of the periodic array is selected to achieve maximum absorption of energy from the electron beam.

83. The device of clause 71, wherein the transparent conductive material comprises indium tin oxide.

84. The device of clause 71, wherein the transparent conductive material comprises doped zinc oxide.

85. The apparatus of clause 71, wherein the transparent conductive material comprises carbon nanotubes.

86. The device of clause 71, wherein the transparent conductive material is an amorphous material.

87. The device of clause 71, wherein the transparent conductive material comprises a doped transparent semiconductor.

88. The device of clause 71, wherein the transparent conductive material comprises a conductive polymer.

89. The device of clause 71, wherein the transparent conductive material comprises a body comprising a transparent material and a coating of conductive material.

90. The device of clause 89, wherein the conductive material coating comprises gold.

91. The apparatus of clause 89, wherein the conductive material coating comprises aluminum.

92. The apparatus of clause 89, wherein the conductive material coating comprises titanium.

93. The apparatus of clause 89, wherein the conductive material coating comprises chromium.

94. The apparatus of clause 70, wherein the structure comprises a post comprising a conductive material.

95. The apparatus of clause 94, wherein the conductive material comprises gold.

96. The device of clause 94, wherein the conductive material comprises silver.

97. The apparatus of clause 94, wherein the column is substantially cylindrical.

98. The apparatus of clause 94, wherein the electron beam propagates along a central axis of the column.

99. The device of clause 94, wherein the radius of the pillar decreases in the direction of electron beam propagation.

100. The apparatus of clause 94, wherein the length of the portion of the column traversed by the electron beam is selected to cause a predetermined amount of deceleration of the electrons in the electron beam.

101. The apparatus of clause 71, wherein the geometric characteristic of the absorbing structure varies along the direction of electron beam propagation.

102. An apparatus for narrowing the energy spread of an electron beam, the apparatus comprising:

a structure defining a cavity extending along a portion of a path of the electron beam, the cavity having an interior surface adapted to absorb energy from electrons in the electron beam to narrow an energy spread of the electron beam.

103. The device of clause 102, wherein the interior surface comprises a metamaterial absorber.

104. The device of clause 103, wherein the metamaterial absorber comprises a layer of transparent conductive material on at least a portion of the interior surface, wherein the layer of transparent conductive material is provided with an absorbent structure.

105. The apparatus of clause 104, wherein the absorbing structure comprises a plasma absorber.

106. The apparatus of clause 104, wherein the absorbing structure resonantly absorbs the electromagnetic energy.

107. The apparatus of clause 104, wherein the absorbent structure is at least partially embedded or coupled to the layer of transparent conductive material.

108. The device of clause 104, wherein the absorbent structure is fabricated on top of the layer of transparent conductive material.

109. The apparatus of clause 104, wherein the absorbent structure is printed on the layer of transparent conductive material.

110. The apparatus of clause 104, wherein the absorbent structure comprises a plurality of bulk elements comprising a metallic material.

111. The apparatus of clause 104, wherein the absorbent structure comprises graphene.

112. The apparatus of clause 104, wherein the absorbent structure comprises a plurality of graphene sheets.

113. The apparatus of clause 104, wherein the absorbent structure comprises a combination of a plurality of bulk metal elements and a plurality of graphene sheets.

114. The device of clause 104, wherein the absorbent structures are arranged in a periodic array.

115. The apparatus of clause 114, wherein the pitch of the periodic array is selected to achieve maximum absorption of energy from the electron beam.

116. The device of clause 104, wherein the transparent conductive material comprises indium tin oxide.

117. The device of clause 104, wherein the transparent conductive material comprises doped zinc oxide.

118. The apparatus of clause 104, wherein the transparent conductive material comprises carbon nanotubes.

119. The apparatus of clause 104, wherein the transparent conductive material comprises an amorphous material.

120. The device of clause 104, wherein the transparent conductive material comprises a doped transparent semiconductor.

121. The apparatus of clause 104, wherein the transparent conductive material comprises a conductive polymer.

122. The apparatus of clause 104, wherein the transparent conductive material comprises a body comprising a transparent material and a coating of conductive material.

123. The apparatus of clause 122, wherein the conductive material coating comprises gold.

124. The apparatus of clause 122, wherein the conductive material coating comprises aluminum.

125. The apparatus of clause 122, wherein the conductive material coating comprises titanium.

126. The apparatus of clause 122, wherein the conductive material coating comprises chromium.

127. The device of clause 102, wherein the structure comprises a post comprising a conductive material.

128. The apparatus of clause 127, wherein the conductive material comprises gold.

129. The device of clause 127, wherein the conductive material comprises silver.

130. The apparatus of clause 127, wherein the column is substantially cylindrical.

131. The apparatus of clause 130, wherein the electron beam propagates along a central axis of the column.

132. The apparatus of clause 130, wherein the radius of the column decreases in the direction of electron beam propagation.

133. The apparatus of clause 130, wherein the length of the portion of the column traversed by the electron beam is selected to cause a predetermined amount of deceleration of the electrons in the electron beam.

134. The apparatus of clause 104, wherein the geometric characteristic of the absorbing structure varies along the direction of electron beam propagation.

135. A method of reducing the width of the energy distribution in an electron beam, the method comprising the steps of: the beam is passed through a volume of space defined by a structure extending along the path of the beam, the structure having a surface provided with a metamaterial absorber arranged to absorb energy from the electrons.

136. The method of clause 135, wherein the metamaterial absorber comprises a layer of transparent conductive material on at least a portion of the surface, wherein the layer of transparent conductive material is provided with a plurality of absorbent structures.

137. The method of clause 136, wherein the absorbent structure is a metamaterial perfect absorber.

138. The method of clause 136, wherein the absorbing structure is a plasma structure.

139. The method of clause 136, wherein the absorbing structure resonantly absorbs electromagnetic energy.

140. The method of clause 136, wherein the absorbent structure is at least partially embedded or coupled to the layer of transparent conductive material.

141. The method of clause 136, wherein the absorbent structure is fabricated on top of the layer of transparent conductive material

142. The method of clause 136, wherein the absorbent structure is printed on the layer of transparent conductive material.

143. The method of clause 136, wherein the absorbent structure comprises a plurality of bulk elements comprising a metallic material.

144. The method of clause 136, wherein the absorbent structure comprises graphene.

145. The method of clause 136, wherein the absorbent structure comprises a plurality of graphene sheets.

146. The method of clause 136, wherein the absorbent structure comprises a combination of a plurality of bulk metal elements and a plurality of graphene sheets.

147. The method of clause 136, wherein the absorbent structures are arranged in a periodic array.

148. The method of clause 147, wherein the pitch of the periodic array is selected to achieve maximum absorption of energy from the electron beam.

149. The method of clause 136, wherein the transparent conductive material comprises indium tin oxide.

150. The method of clause 136, wherein the transparent conductive material comprises doped zinc oxide.

151. The method of clause 136, wherein the transparent conductive material comprises carbon nanotubes.

152. The method of clause 136, wherein the transparent conductive material comprises an amorphous material.

153. The method of clause 136, wherein the transparent conductive material comprises a doped transparent semiconductor.

154. The method of clause 136, wherein the transparent conductive material comprises a conductive polymer.

155. The method of clause 136, wherein the transparent conductive material comprises a body comprising a transparent material and a coating of conductive material.

156. The method of clause 155, wherein the conductive material coating comprises gold.

157. The method of clause 155, wherein the conductive material coating comprises aluminum.

158. The method of clause 155, wherein the conductive material coating comprises titanium.

159. The method of clause 155, wherein the conductive material coating comprises chromium.

160. The method of clause 135, wherein the structure comprises a substantially cylindrical column.

161. The method of clause 160, wherein the substantially cylindrical column comprises an electrically conductive material.

162. The method of clause 160, wherein the electron beam propagates along a central axis of the column.

163. The method of clause 160, wherein the radius of the substantially cylindrical column decreases in the direction of electron beam propagation.

164. The method of clause 160, wherein the length of the portion of the column traversed by the electron beam is selected to cause a predetermined amount of deceleration of electrons in the electron beam.

165. The method of clause 136, wherein the size of the absorbing structure varies along the direction of electron beam propagation.

166. An apparatus for narrowing the energy spread of a charged particle beam, the apparatus comprising:

a structure defining a cavity extending along a portion of a path of the charged electron beam, the cavity having an interior surface; and

a metamaterial absorber disposed on the interior surface.

167. The device of clause 166, wherein the metamaterial absorber comprises a layer of dielectric material on at least a portion of the interior surface, wherein the layer of transparent conductive material is provided with a plurality of absorbent structures.

168. The device of clause 166, wherein the metamaterial absorber comprises a layer of transparent conductive material on at least a portion of the interior surface, wherein the layer of transparent conductive material is provided with a plurality of absorbent structures.

169. The apparatus of clause 168, wherein the absorbent structure is a metamaterial perfect absorber.

170. The apparatus of clause 168, wherein the absorbing structure is a plasma structure.

171. The apparatus of clause 168, wherein the absorbing structure resonantly absorbs electromagnetic energy.

172. The apparatus of clause 168, wherein the absorbent structure is at least partially embedded or coupled to the layer of transparent conductive material.

173. The apparatus of clause 168, wherein the absorbing structure is fabricated on top of the layer of transparent conductive material.

174. The apparatus of clause 168, wherein the absorbent structure is printed on the layer of transparent conductive material.

175. The apparatus of clause 168, wherein the absorbent structure comprises a plurality of mass elements comprising a metallic material.

176. The apparatus of clause 168, wherein the absorbent structure comprises graphene.

177. The apparatus of clause 168, wherein the absorbent structure comprises a plurality of graphene sheets.

178. The apparatus of clause 168, wherein the absorbent structure comprises a combination of a plurality of bulk metal elements and a plurality of graphene sheets.

179. The device of clause 168, wherein the absorbent structures are arranged in a periodic array.

180. A method of reducing the width of an energy distribution in a charged particle beam, the method comprising the steps of: the beam is passed through a volume of space defined by a structure extending along the path of the beam, the structure having a surface provided with a metamaterial absorber arranged to absorb energy from the charged particles.

181. An apparatus, comprising:

a first set of pixels configured to shape a first beamlet proximate to the first set of pixels; and

a first set of pixel control means associated with each pixel of the first set of pixels, respectively, each pixel control means being arranged and configured to apply a signal to the associated pixel for shaping the first sub-beam.

182. The apparatus of clause 181, wherein the first set of pixels has a voltage profile configured to be adjusted based on reflections of charged particles associated with the first beamlet above the first set of pixels.

183. The apparatus of any of clauses 181 or 182, wherein the first beamlet is shaped to cause a reduction in aberrations.

184. The apparatus of any of clauses 181-183, wherein the first set of pixels and the first set of pixel control means are implemented in a component.

185. The apparatus of any of clauses 181-183, wherein the first set of pixels and the first set of pixel control means are implemented in separate components.

186. The apparatus of any of clauses 181-183, wherein each pixel of the first set of pixels and a corresponding pixel control means of the first set of pixels control means are implemented in a means.

187. The apparatus of any of clauses 181-183, wherein each pixel of the first set of pixels and the corresponding pixel control means of the first set of pixels control means are implemented in separate means.

188. The apparatus of any of clauses 181-187, wherein the signal triggers the associated pixel to generate an electric field for shaping the first beamlet.

189. The apparatus of any of clauses 181-187, wherein the first set of pixels is further configured to reflect the shaped first sub-beam.

190. The apparatus of any of clauses 181-189, wherein the signal comprises a negative voltage to enable the associated pixel to reflect or remove negatively charged particles of the first sub-beam from the first sub-beam.

191. The apparatus of any of clauses 181-190, wherein the first set of pixels comprises a subset of pixels tilted to remove charged particles from the first beamlet.

192. The apparatus of any of clauses 181-189, wherein the signal comprises a positive voltage to enable the associated pixel to reflect positively charged particles of the first sub-beam or remove negatively charged particles from the first sub-beam.

193. The apparatus of any of clauses 181-192, wherein the signal comprises an AC voltage to shape the profile of the first sub-beam in synchronization with the beam scanned over the sample.

194. The apparatus of any of clauses 181-193, further comprising:

a second set of pixels configured to shape a second beamlet proximate to the second set of pixels; and

a second set of pixel control means is associated with each of the second pixels, respectively, each pixel control means being arranged and configured to apply a signal to the associated pixel to shape the second sub-beam.

195. The device of clause 194, wherein the first set of pixels and the second set of pixels are part of a mirror plate.

196. The device of clause 194, wherein each of the first set of pixels and the second set of pixels comprises a rectangular, hexagonal, or circular sector set of pixels.

197. The device of any of clauses 194-196, wherein the first set of pixels and the second set of pixels are arranged in a square pattern or a hexagonal pattern.

198. The device of clause 181, wherein the first set of pixels comprises pixels of different sizes and shapes.

199. The apparatus of clause 181, wherein the first set of pixels is disposed on a plate-shaped member, and the plate-shaped member is curved, the curvature of the plate-shaped member being adjusted by a mechanical actuator.

200. The apparatus of clause 181, wherein the first set of pixel control components is configured to apply a negative voltage, zero voltage, or a positive voltage to shape the first beamlet.

201. The apparatus of clause 181, wherein the first set of pixels has a voltage profile configured to be adjusted based on a landing energy of charged particles associated with the first beamlet.

202. The apparatus of clause 181, wherein the first set of pixels has a voltage profile configured to be adjusted based on a current of the charged particles associated with the first beamlet.

203. The apparatus of clause 181, wherein the first set of pixels has a voltage profile configured to be adjusted based on a landing angle at the sample.

204. The apparatus of clause 181, wherein the first set of pixels has a voltage profile configured to be adjusted based on the magnitude of the electric field at the sample.

205. A system for manipulating a charged particle beamlet, comprising:

a charged particle beam source; and

a programmable charged particle mirror plate arranged to receive the sub-beam and configured to shape the sub-beam.

206. The system of clause 205, further comprising:

a charged particle beam source; and

a programmable charged particle mirror plate arranged to receive the sub-beam and configured to shape the sub-beam.

207. The system of clause 205, further comprising:

a plurality of electrodes configured to affect the guided beamlets; and

a plurality of drivers respectively associated with each of the plurality of electrodes, each driver configured to provide an adjustable voltage.

208. The system of clause 205, further comprising:

a plurality of electromagnetic optical elements coupled with the adjustable excitation, configured to affect the guided sub-beam; and

a plurality of drivers respectively associated with each of the plurality of electromagnetic optical elements, each driver configured to adjust an excitation of a corresponding electromagnetic optical element.

209. The system of clause 205, further comprising:

an optical element for directing the sub-beam to the programmable charged particle mirror plate,

wherein the programmable charged particle mirror plate can be further configured to direct the shaped sub-beams to the optical element.

211. The system of clause 209, wherein the optical element is configured to receive and direct the plurality of sub-beams, and the programmable charged particle mirror plate is arranged to receive and reflect the plurality of sub-beams.

211. The system of clause 205, wherein the programmable charged particle mirror plate has a plurality of controlled pixels in the mirror plate, each beamlet of the plurality of beamlets corresponding to an associated set of controlled pixels configured to shape the respective beamlet.

212. A method for shaping beamlets of charged particles, the method comprising:

directing the first charged particle beamlet towards a charged particle mirror plate using an optical element; and

the first sub-beam is shaped using the charged particle mirror plate by providing a signal to a first set of pixels of the charged particle mirror plate to generate an electric field and by reflecting the shaped sub-beam.

213. The method of clause 212, wherein the shaped beamlets are directed to an optical element.

214. The method of clause 212, further comprising:

directing the second charged particle beamlet towards the charged particle mirror plate using an optical element; and

the second sub-beam is shaped using the charged particle mirror plate by providing signals to the second set of pixels of the charged particle mirror plate to generate an electric field and by reflecting the shaped sub-beam to the optical element.

215. A non-transitory computer readable medium storing a set of instructions executable by a controller of an apparatus to cause the apparatus to perform a method of shaping a charged particle beam, the method comprising:

directing the first charged particle beamlet towards a charged particle mirror plate using an optical element; and

the first sub-beam is shaped using the charged particle mirror plate by providing signals to a first set of pixels of the charged particle mirror plate to generate an electric field and by reflecting the shaped sub-beam to the optical element.

216. The non-transitory computer readable medium of clause 215, wherein the set of instructions is executable by the controller of the apparatus to cause the apparatus to further perform:

directing the second charged particle beamlet towards the charged particle mirror plate using an optical element; and

the second sub-beam is shaped by providing a signal to a second set of pixels of the charged particle mirror plate to generate an electric field and reflecting the shaped sub-beam to the optical element through the charged particle mirror plate.

217. An apparatus, comprising:

an absorptive component configured to manipulate beamlets proximate the absorptive component by absorbing electromagnetic energy to reduce energy spread; and

a mirror plate configured to shape the sub-beam, the mirror plate embedded or coupled to the absorbing component.

218. The apparatus of clause 217, wherein the absorbent member comprises:

an absorptive structure set configured to absorb electromagnetic energy; and

a transparent conductor layer embedded or coupled to the collection of absorbing structures, the transparent conductor layer disposed on top of the mirror plate.

219. The apparatus of clause 218, wherein the collection of absorbing structures can be tuned by choosing shapes and sizes and altering the pitch between absorbing structures to reduce energy spreading of the beamlets.

220. The apparatus of clause 218, wherein the collection of absorbent structures comprises a plurality of graphene sheets.

221. The apparatus of clause 218, wherein the collection of absorbent structures comprises a metallic element.

222. The apparatus of clause 218, wherein the collection of absorbent structures comprises a combination of a metal element and a plurality of graphene sheets.

223. The device of clause 218, wherein the transparent conductor layer comprises a dielectric material.

224. The apparatus of clause 218, wherein the transparent conductor layer comprises a transparent conductive material.

225. The apparatus of clause 219, wherein the transparent conductive material conducts stray electrons of the sub-beams impinging on the transparent conductor layer away from the absorbing member and avoids charging the absorbing member.

226. The device of clause 217, wherein the mirror plate comprises:

a set of pixels configured to shape the beamlets proximate to the group of pixels; and

a set of pixel control means associated with each pixel in the set of pixels respectively, each pixel control means being arranged and configured to apply a signal to the associated pixel for shaping the sub-beam.

227. The apparatus of clause 226, wherein the set of pixels has a voltage distribution configured to be adjusted based on reflections of charged particles associated with the beamlets above the set of pixels.

228. The apparatus of clause 226, wherein the beamlets are shaped to cause a reduction in aberrations.

229. The apparatus of clause 226, wherein the signal triggers the associated pixel to generate an electric field for shaping the beamlet.

230. The apparatus of clause 226, wherein the set of pixels is further configured to reflect the shaped and steered sub-beams.

231. The device of clause 226, wherein each pixel in the set of pixels has a corresponding absorption component.

232. A system for manipulating a charged particle beamlet, comprising:

a charged particle beam source; and

an absorptive component configured to manipulate the beamlets proximate the absorptive component by reducing energy spread by absorbing electromagnetic energy.

233. The system of clause 232, further comprising:

a programmable charged particle mirror plate arranged to receive the sub-beam and configured to shape the sub-beam, the mirror plate being embedded in or coupled to the absorbing component.

234. The system of any of clauses 232 and 233, further comprising:

a first optical element configured to direct the sub-beam to an absorbing component,

wherein the absorbing member may be further configured to direct the steered sub-beam to the first optical element.

235. The system of clause 234, wherein the first optical element is configured to receive and direct the plurality of sub-beams, and the absorbing member is arranged to receive and reflect the plurality of sub-beams.

236. The system of clause 234, wherein the first optical element is further configured to direct the steered beamlet from the absorbing member to another direction.

237. The system of any of clauses 233-236, further comprising:

a second optical element configured to direct the sub-beam to the programmable charged particle mirror plate,

wherein the programmable charged particle mirror plate can be further configured to direct the shaped sub-beam to the second optical element.

238. The system of clause 237, wherein the second optical element is configured to receive and direct the plurality of sub-beams, and the programmable charged particle mirror plate is arranged to receive and reflect the plurality of sub-beams.

239. The system of clause 237, wherein the second optical element is further configured to direct the shaped sub-beams from the programmable charged particle mirror plate to another direction.

240. The system of clause 237, wherein the second optical element is located upstream of the first optical element.

241. The system of clause 237, wherein the first optical element is located upstream of the second optical element.

242. A method for manipulating a charged particle beamlet, the method comprising:

directing a charged particle beamlet using an optical element towards a structure comprising a charged particle mirror plate and an absorbing component;

manipulating the beamlets using the absorbing member by using an absorbing structure of the absorbing member to reduce energy spread of the beamlets; and

the charged particle mirror plate is used to shape the sub-beams by providing signals to a set of pixels of the charged particle mirror plate to generate an electric field and by reflecting the shaped and manipulated sub-beams.

243. The method of clause 242, wherein the shaped and manipulated sub-beams are directed to an optical element.

244. A method for manipulating a charged particle beamlet, the method comprising:

manipulating the beamlets using the absorbing member by using an absorbing structure of the absorbing member to reduce energy spread of the beamlets; and

the charged particle mirror plate is used to shape the sub-beams by providing signals to a set of pixels of the charged particle mirror plate to generate an electric field and by reflecting the shaped sub-beams.

245. The method of clause 244, further comprising: the charged particle beamlets are directed towards the absorbing member using a first optical element.

246. The method of clause 245, wherein steering the beamlets comprises: the steered sub-beam is reflected to a first optical element.

247. The method of clause 246, further comprising: the sub-beam received from the absorbing component is directed towards a downstream component using a first optical element.

248. The method of any of clauses 245-246, further comprising: the sub-beam is directed towards the charged particle mirror plate using a second optical element.

249. The method of clause 248, wherein the second optical element is located downstream of the first separator.

250. The method of clause 248, wherein the shaped sub-beam is reflected to the second optical element.

251. The method of clause 248, further comprising: the shaped sub-beam is directed towards another downstream component using a second optical element.

252. The method of clause 251, wherein the other downstream component comprises a first optical element.

253. A non-transitory computer readable medium storing a set of instructions executable by a controller of an apparatus to cause the apparatus to perform a method of manipulating a charged particle beamlet, the method comprising:

directing the charged particle beamlets using optical components towards a structure comprising a charged particle mirror plate and an absorbing component;

manipulating the beamlets using the absorbing member by using an absorbing structure of the absorbing member to reduce energy spread of the beamlets; and

the charged particle mirror plate is used to shape the sub-beams by providing signals to a set of pixels of the charged particle mirror plate to generate an electric field and by reflecting the shaped and manipulated sub-beams.

254. A non-transitory computer readable medium storing a set of instructions executable by a controller of an apparatus to cause the apparatus to perform a method of manipulating a charged particle beamlet, the method comprising:

manipulating the beamlets using the absorbing member to reduce energy spread of the beamlets by using an absorbing structure of the absorbing member; and

the charged particle mirror plate is used to shape the sub-beams by providing signals to a set of pixels of the charged particle mirror plate to generate an electric field and by reflecting the shaped sub-beams.

The foregoing description of the specific embodiments will so fully reveal the general nature of the invention that others can, by applying knowledge within the skill of the art, readily modify and/or adapt for various applications such specific embodiments without undue experimentation, without departing from the general concept of the present invention. Therefore, such modifications and adaptations are intended to be within the meaning and range of equivalents of the disclosed embodiments, based on the teaching and guidance presented herein. It is to be understood that the phraseology or terminology herein is for the purpose of description and not of limitation, such that the terminology or phraseology of the present specification is to be interpreted by the skilled artisan in light of the teachings and guidance.