Charged particle blocking element, exposure apparatus equipped with such an element, and method of using such an exposure apparatus - Patents.com

Abstract

To provide a charged particle exposure apparatus which at least partially reduces heating of components within the exposure apparatus, and a component therefor.SOLUTION: The present invention relates to an exposure apparatus and a method of projecting a charged particle beam to a target. The exposure apparatus includes a charged particle optical arrangement including: a charged particle source for generating a charged particle beam; and a charged particle blocking element and / or a current limiting element for blocking at least a part of a charged particle beam from a charged particle source. The charged particle blocking element and the current limiting element include a substantially flat substrate provided with an absorbing layer including boron, carbon or beryllium. The substrate further preferably includes one or more apertures for transmitting charged particles. The absorbing layer is arranged spaced apart from the at least one aperture.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The invention relates to a charged particle blocking element for use in a charged particle optical apparatus for projecting a charged particle beam onto a target. The invention further relates to an exposure apparatus for projecting a charged particle beam onto a target, comprising a charged particle blocking element, and to a method for projecting a charged particle beam onto a target using such an exposure apparatus. The invention also relates to a method for manufacturing semiconductor devices and / or for inspecting a target using such an exposure apparatus. [Background technology]

[0002] In the semiconductor industry, there is an ever-increasing demand to manufacture smaller structures with high precision and reliability. Charged particle beam exposure tools allow a target surface to be exposed to one or more beams of charged particles that are precisely aimed and focused at the target surface. Additionally, the use of charged particles allows for much higher resolution and precision for transferring or analyzing patterns on the target surface compared to exposure tools that use light to expose the target surface.

[0003] However, to be commercially viable, a charged particle exposure apparatus must be able to meet stringent requirements for significant wafer throughput and tight tolerances for both lithography and inspection systems. Higher throughput can be achieved by using more charged particle beams, and therefore more current, in the exposure apparatus.

[0004] However, increasing the current also increases the number of charged particles that interact with components within the exposure apparatus. Collisions between the charged particles and system components within the exposure apparatus can cause significant heating in each component.

[0005] Problems related to heating of components in charged particle beam systems are typically solved by actively cooling such components, as described, for example, in granted U.S. Pat. Nos. 8,558,196 and 9,165,693 and in international patent application published as WO 2013 / 171216.

[0006] The article by M. van Zaalen in "VAN TEKENTAFEL NAAR OVEN", Link Magazine, XVIII:1 (February 2016), pages 28 and 29, identifies the problem of heating of the collimator lenses in maskless multi-electron beam lithography systems, caused by the high electric field in the collimator and the high current of the electron beam focused by the collimator. As M. van Zaalen also points out in his article, the electrons of the charged particle beam do not all pass through the collimator, but some are reflected in it. This phenomenon also contributes to the heating of the collimator. Heating of the beam steering components can result in thermal deformations that reduce the accuracy of the exposure process. As described in M. van Zaalen's article, this is solved by a redesign of the suspension of the collimator in the lithography apparatus. There, the cooling of the collimator is improved by allowing the heat to be removed from the collimator by thermal conduction through the improved suspension. Summary of the Invention

[0007] It is an object of the present invention to provide a charged particle exposure apparatus, and components thereof, which at least partially reduces heating of components within the exposure apparatus. Charged particles should be understood to include both electrons and ions. When referring to a charged particle beam, this may consist of either electrons or ions. The present invention is particularly related to electron beam exposure apparatus, including electron (multi)beam lithography systems, various electron microscopes, and inspection systems. However, the present invention may also be applied to systems using other types of charged particles, including positively or negatively charged ions, e.g. helium ions.

[0008] According to a first aspect, the present invention provides a charged particle blocking element for blocking charged particles, the charged particle blocking element comprising a substrate, the substrate comprising at least one aperture for passing charged particles, at least a portion of a surface of the substrate being provided with an absorbent layer made of a material comprising boron, carbon or beryllium, the absorbent layer being spaced apart from the at least one aperture, and at least a portion of the surface of the substrate provided with the absorbent layer comprises a conductive material.

[0009] The absorbing layer at least partially absorbs the impinging charged particles, i.e. it has the function of receiving the impinging charged particles, whose charge is transferred onto the conductive material so as to be carried away from the charged particle blocking element. The conductive material can be achieved by providing a conductive layer on a substrate located below the absorbing layer, or by providing the substrate as at least partially conductive, e.g. such that at least a part of the surface on which the absorbing layer is provided is conductive.

[0010] The charged particle blocking element is suitable for blocking charged particles in various applications. It can be used in a charged particle exposure apparatus and / or an inspection apparatus to at least partially block a beam of charged particles along its trajectory. This may be for example for shaping one or more beams in a current-limited aperture array element. It can be used for example in one or more of the aperture arrays in the system described in US Pat. No. 8,653,485 B2, in particular in the aperture array 4A of the system shown in FIG. 12 of US Pat. No. 8,653,485 B2. It can also be used as a shutter element to completely block the beam or the beam source, thereby temporarily switching it off without having to switch off the beam source itself. This may be particularly advantageous in cases where switching on the beam source usually involves a significant settling time. In the system shown in FIG. 12 of US Pat. No. 8,653,485 B2, it can be located at a location between the beam source 1 and the collimator 3.

[0011] In particular, when the charged particle blocking element is used as a current limiting aperture, it is advantageous to arrange the absorbing layer on the substrate spaced apart from the at least one aperture, in order to at least substantially prevent material of the absorbing layer being arranged at or overhanging the edge of the at least one aperture or being arranged inside the at least one aperture, which may distort and / or disturb the charged particle beam traversing said at least one aperture.

[0012] In particular, the absorbing layer is arranged on a surface of the substrate that is arranged, in use, facing the charged particle source, such that the charged particle blocking element, when used to block at least a portion of the charged particle beam from the charged particle source, can be arranged such that at least a majority of the blocked portion of the charged particle beam impinges on the absorbing layer. It is therefore preferred that the absorbing layer is arranged near the at least one aperture.

[0013] Surprisingly, the inventors have discovered that when an absorbing layer made of a material containing boron, carbon or beryllium is used to block at least a portion of the charged particle beam, the heat load on charged particle optical components located between the charged particle blocking element and the charged particle source is significantly reduced compared to a charged particle blocking element that does not use such an absorbing layer. This is particularly true for charged particle optical components that are directly adjacent to the charged particle blocking element and / or have an unobstructed line of sight to the charged particle blocking element. By reducing the heat load on these charged particle optical components, the exposure apparatus can operate for longer periods without the charged particle optical components becoming excessively hot and / or cooling of the charged particle optical components becomes less critical.

[0014] As discussed above, the main objective leading to the present invention was to reduce the thermal load on components in charged particle exposure systems, such as those described in US Pat. No. 8,653,485 B2, US Pat. No. 8,558,196 B2, US Pat. No. 9,165,693 B2 and WO 2013 / 171216. This has been achieved by the charged particle blocking element described herein, particularly when used in a current-limited aperture array. The inventors have also discovered that when an absorbing layer made of a material comprising boron, carbon or beryllium is used to block at least a portion of the charged particle beam, the aberrations of the charged particle beam at the surface of the target are significantly reduced. Thus, in addition to the main effect of reducing the thermal load, a secondary effect of reducing the aberrations of the charged particle beam in the exposure system has been observed. Furthermore, it has been observed that both the thermal load and the aberrations are reduced even when the surface receiving the charged particle beam is only partially coated with an absorbing layer. However, it is preferred that a large portion of the blocked charged particle beam impinges on the absorbing layer.

[0015] The inventors' findings appear to suggest that heating of components upstream of the charged particle blocking element relative to the beam of charged particles, and the formation of space charges that may disrupt the trajectories of the charged particles, may be due to backscattered charged particles and / or secondary electrons generated by the portion of the charged particle beam that is blocked by a charged particle impinging on the charged particle blocking element. Secondary electrons may result from backscattered charged particles impinging on the surface of another element in the system. By providing an absorbing layer according to the invention on the side of the charged particle blocking element that receives the charged particles to be blocked in use, at least the amount of backscattering can be reduced.

[0016] It should be noted that in the context of this application, an absorbing layer made of a material containing boron, carbon or beryllium also encompasses an absorbing layer made of a material containing a combination of boron, carbon or beryllium with one or more other elements, such as boron nitride or silicon carbide.

[0017] Preferably, the absorbing layer comprises boron. In particular, the absorbing layer is a boron layer or a boron nitride layer. Preferably, the absorbing layer is a boron coating or a boron nitride coating. The coating is a thin layer or film, typically having a thickness of tens or hundreds of nm, applied to the surface of the object. The boron layer or the boron coating is preferably a substantially pure boron layer. Boron is advantageous because it is non-toxic, stable at room temperature, does not oxidize in air, and can be applied using known techniques such as sputtering or evaporation.

[0018] A disadvantage of using boron or boron nitride layers to block charged particles is that these materials have a relatively high electrical resistivity, which makes them an obvious choice when searching for materials to block charged particles: the absorbing layer becomes charged in use by charged particles impinging on it, and this charge is difficult to remove by electrical conduction through the absorbing layer when an absorbing layer made of a material with high electrical resistivity is used.

[0019] Therefore, apart from the strategy of combining such a layer with a conductive layer or a conductive substrate, another insight underlying the present invention is that the thickness of the absorbing layer should be carefully selected.

[0020] Advantageously, the absorbing layer has a thickness sufficient to prevent backscattering of charged particles from a portion of the substrate located below the absorbing layer, and thin enough for the conductive surface to receive the charge of the charged particles. This allows efficient absorption of the charged particles, i.e., very low amounts of backscattering of the charged particles, while avoiding charge build-up in the absorbing layer by removal of the absorbed charge via the conductive surface. As the layer thickness increases, at least up to the stabilization threshold, the probability of backscattering decreases, but the increasing layer thickness reduces the electrical conductivity with the layer thickness. If the absorbing layer becomes too thick, it will essentially act as an electrical insulator.

[0021] In certain embodiments, the absorbing layer has a thickness between 100 nm and 500 nm. In more preferred embodiments, the absorbing layer has a thickness between 150 and 250 nm. It has been observed that an absorbing layer thickness in this range reduces heating of a charged particle optical element disposed between the charged particle blocking element and the charged particle source while avoiding charge build-up on the charged particle blocking element.

[0022] In an embodiment, at least a part of the substrate is electrically conductive. This can be achieved by providing the substrate with an electrically conductive, for example metallic, material, by a substrate comprising an electrically conductive material, or by a highly doped semiconductor substrate, which is highly doped at least in the area where the absorber layer is provided. For example, highly doped silicon may be used. Thereby, the substrate can help to remove charge from the absorber layer. Preferably, the substrate comprises a connection for connecting the substrate to a voltage source or to a ground potential. In an embodiment, the connection comprises a connection area, also referred to as a contact area, preferably constituting part of the surface of the substrate or arranged on the surface of the substrate, which connection area is configured to connect the substrate to a voltage source or to a ground potential. In particular, connecting a conductive substrate to a ground potential allows to remove charge from the absorber layer by electrical conduction through the substrate.

[0023] In an embodiment, the substrate is provided with a conductive layer, which is at least partially disposed between the substrate and the absorbing layer. The conductive layer can thereby assist in removing charge from the absorbing layer. Preferably, the conductive layer comprises a material comprising molybdenum (Mo) or chromium (Cr). The conductive layer may be formed of substantially pure molybdenum or chromium, or the conductive layer may be formed of a material comprising at least one of these elements. In particular, molybdenum is preferred because molybdenum oxide is also conductive, which ensures that the layer of molybdenum is conductive even when the molybdenum is at least partially oxidized. In this embodiment, substrate properties related to conductivity are less important. In this embodiment, the substrate may be, for example, a relatively lightly doped or substantially undoped semiconductor substrate.

[0024] Since the conductive layer is at least partially disposed between the substrate and the absorbing layer, the absorbing layer can act as a protective coating for the conductive layer, thereby protecting the conductive layer from oxidation at least in the part covered by the absorbing layer, which also allows the use of other conductive materials for the conductive layer, such as copper (Cu) or aluminum (Al).

[0025] Preferably, the charged particle blocking element is electrically conductive and comprises a connection or region connected to the conductive layer, the connection or region being configured to connect the conductive layer to a ground potential or a control voltage to aid in removing the charge of the absorbing layer by electrical conduction through the conductive layer. In an embodiment, the connection comprises a connection region, also referred to as a contact region, preferably constituting part of the substrate or arranged on the substrate, the connection region being configured to connect the conductive layer to a voltage source or to a ground potential.

[0026] In one embodiment, the substrate comprises a silicon (Si) wafer. Si wafers provide a flat, mechanically stable substrate that can be easily provided with apertures using etching techniques well known in the art. This is particularly advantageous in embodiments where the charged particle blocking element is provided with multiple apertures. Such a charged particle blocking element can be used as a current limiting element, as discussed below. Since Si typically has a high electrical resistance, at least when the Si is undoped, it is preferred to provide a Si wafer substrate with a conductive layer on which an absorbing layer is disposed as described above.

[0027] In an embodiment, the substrate is provided with at least one aperture for passing charged particles. The charged particle blocking element may be arranged in the charged particle beam path to pass at least a portion of the charged particle beam through the at least one aperture while allowing at least partial and / or temporary blocking of the charged particle beam by non-aperture areas on the substrate. An aperture is often referred to as a current-limiting aperture when it passes only a portion of the charged particle beam, typically a central portion, while blocking other portions of the charged particle beam.

[0028] In an embodiment, a substrate is provided with a plurality of apertures configured to form one or more aperture arrays, each arranged in a corresponding array region, or aperture array region, of the substrate. Such an element may be used as a current-limiting aperture array in a charged particle beam system, which may be used, for example, to split a charged particle beam into multiple charged particle beams.

[0029] The absorbing layer preferably at least partially surrounds said array area. In some embodiments, the charged particle beam is larger than the area surrounding one or more aperture arrays such that a large portion of the charged particle beam blocked by the blocking element falls on the absorbing layer even if it does not extend to the surface area located between the individual apertures or array areas. Such an embodiment may be easier to manufacture while avoiding portions of the absorbing layer extending into the apertures. As mentioned above, it has been observed that such partial coverage of the charged particle receiving surface by the absorbing layer substantially reduces heating of the component and / or aberrations of the charged particle beam.

[0030] In another embodiment, each array region is at least partially surrounded by said absorbing layer. In yet another embodiment, the absorbing layer is further disposed at least partially within each aperture array region. This may increase the portion of the charged particle beam that is absorbed by the charged particle blocking element.

[0031] In an embodiment, the charged particle blocking element comprises a cooling channel for cooling at least the substrate. Preferably, the cooling channel is arranged in thermal contact with the absorber layer and / or the substrate. This allows the charged particle blocking element to be provided with a cooling channel for directing a cooling fluid (such as water) through said cooling channel for removing heat from the charged particle blocking element. In an embodiment, the cooling channel is arranged on a surface of the substrate facing away from the absorber layer. In an embodiment for use in a charged particle beam system, the cooling channel is arranged on a surface of the substrate facing away from the charged particle source.

[0032] In an embodiment, the substrate is provided with a separate electrically and / or thermally conductive layer arranged in contact with the absorber layer and the cooling channels. The thermally conductive layer provides a thermally conductive path from the absorber layer to the cooling channels. This embodiment allows the use of a substrate made of a material that does not have good thermal conductive properties. The separate electrically conductive layer provides a conductive path from the absorber layer to the cooling channels. The separate electrically conductive layer can thereby help to remove charge from the absorber layer via the cooling channels, which are normally connected to ground potential when used in an exposure apparatus. Also, by electrically connecting the absorber layer to the cooling channels, no dedicated contact area or contact arrangement is required on the side of the charged particle blocking element facing away from the side containing the cooling channels. This allows the side of the charged particle blocking element facing away from the side containing the cooling channels to be placed in close proximity to adjacent elements or components of the charged particle optical device.

[0033] According to a second aspect, the present invention provides a current limiting element for use in a charged particle exposure apparatus, the current limiting element comprising a substrate that is opaque to charged particles, the substrate having one or more apertures penetrating the substrate from a first surface to a second surface thereof for passing charged particles, and an absorption layer comprising boron (B), carbon (C) or beryllium (Be) provided on at least a portion of the first surface, the absorption layer being spaced apart from the one or more apertures, the absorption layer being provided on a conductive material or a conductive surface.

[0034] It should be noted that the current limiting element is typically used to limit the current of the charged particle beam. Therefore, the diameter of the one or more apertures is smaller than the diameter of the charged particle beam. The apertures are typically manufactured with precision, since the current limiting element at least partially defines the cross section of the charged particle beam that has crossed the current limiting element. By arranging the absorbing layer at a distance from the one or more apertures, disturbances at least at the edge of the one or more apertures by the absorbing layer can be avoided.

[0035] The current limiting element according to the second aspect provides the same or corresponding technical effects and advantages as the charged particle blocking element according to the first aspect described herein above. The charged particle blocking element according to the first aspect, in embodiments in which the substrate is provided with one or more apertures, may be used as the current limiting element according to the second aspect.

[0036] The current-limiting element according to the second aspect may be combined with one or more of the embodiments and / or alternative embodiments of the charged particle blocking element according to the first aspect.

[0037] According to a third aspect, the present invention provides a shutter element for at least temporarily blocking a charged particle beam, the shutter element comprising a substrate provided with an absorbing layer comprising boron (B), carbon (C) or beryllium (Be) in at least a part thereof, the absorbing layer being provided on a conductive surface on the substrate.

[0038] It should be noted that the shutter elements, in use, are configured to temporarily permit the charged particle beam to pass through the shutter element, and to temporarily block the charged particle beam.

[0039] In situations where the charged particle beam is allowed to pass through the shutter element, the charged particle beam passes at least along the edge or through the aperture of said shutter element. If the shutter element in this situation is configured to also perform the function of a current limiting element, the absorbing layer is preferably located away from the edge or aperture. However, if the shutter element in this situation is not configured to perform the function of a current limiting element, in particular if the charged particle beam is spaced away from the edge or periphery of the aperture, the absorbing layer may be located up to the edge or periphery of the aperture.

[0040] The shutter element may be realised by the charged particle blocking element of the first embodiment.

[0041] The shutter element of the third aspect may be combined with one or more of the embodiments and / or alternative embodiments of the charged particle blocking element according to the first aspect.

[0042] According to a fourth aspect, the present invention provides an exposure apparatus for projecting a charged particle beam onto a target, the exposure apparatus comprising a charged particle optical device for forming a charged particle beam and for projecting the charged particle beam onto the target, the charged particle optical device comprising a charged particle source for generating the charged particle beam and a charged particle blocking element according to the first aspect capable of blocking at least a part of the charged particle beam from the charged particle source, a current limiting element according to the second aspect configured to limit a charged particle current of the charged particle beam, and / or a shutter element according to the third aspect.

[0043] In an embodiment, the absorbing layer of the charged particle blocking element, current limiting element and / or shutter element is disposed on a surface of the substrate facing towards a source of charged particles and / or a source of backscattered and / or secondary electrons in the device.

[0044] In an embodiment, the charged particle blocking element comprises one or more apertures configured as a current-limiting aperture or a current-limiting aperture array of the exposure apparatus.

[0045] In an embodiment, the charged particle blocking element and / or the current limiting element comprises an array of apertures for splitting a charged particle beam into multiple charged particle beams. Thus, the charged particle blocking element and / or the current limiting element can be used to generate multiple charged particle beams from a single large diameter beam. Typical applications are charged particle multi-beam lithography systems, charged particle multi-beam inspection systems, and charged particle multi-beam microscopes.

[0046] In an embodiment, the charged particle optical device comprises a modulation deflector for deflecting the charged particle beam to the charged particle blocking element, the modulation deflector and the charged particle blocking element being configured to allow the charged particle beam to pass through the aperture of the charged particle blocking element when the charged particle beam is not deflected by the deflector, or vice versa, to at least partially block the charged particle beam by the charged particle blocking element when the charged particle beam is deflected by the deflector. Thereby, the charged particle blocking element of this embodiment is used to modulate the charged particle beam, in particular to switch the charged particle beam on or off. A typical application example is a charged particle (multi) beam lithography system.

[0047] According to a fifth aspect, the present invention provides a charged particle lithography system comprising an exposure apparatus as described above or an embodiment thereof.

[0048] According to a sixth aspect, the present invention provides a charged particle inspection system or a charged particle microscope comprising an exposure apparatus as described above or an embodiment thereof.

[0049] According to a seventh aspect, the present invention provides a method of projecting a charged particle beam onto a target using the exposure apparatus described above, the method comprising a step of blocking at least a part of the charged particle beam from a charged particle source, wherein at least a part of the blocked charged particle beam falls on an absorbing layer of a charged particle blocking element or a current limiting element.

[0050] According to an eighth aspect, the present invention provides a method for manufacturing a semiconductor device using the above-mentioned exposure apparatus, the method comprising: positioning a wafer downstream of the charged particle optical device; processing the wafer, the processing comprising projecting an image or pattern onto the wafer using a charged particle beam generated, shaped and / or modulated by the charged particle optical device; performing subsequent steps to produce semiconductor devices using the processed wafer; The present invention provides a method comprising:

[0051] Subsequent steps for fabricating semiconductor devices from the processed wafers are well known in the art of semiconductor device fabrication, many of which are described, for example, in commonly owned U.S. Patent Application Publication No. US2014 / 0176920A1.

[0052] According to a ninth aspect, the present invention provides a method for inspecting a target using the exposure apparatus described above, the method comprising: positioning the target downstream of the charged particle optical device; directing a charged particle beam generated and shaped by the charged particle optical device toward the target; detecting charged particles transmitted, emitted and / or reflected by a target when the charged particle beam is incident on the target; performing a subsequent step to inspect the target using data from the step of detecting the charged particles; The present invention provides a method comprising:

[0053] The different embodiments described above can be combined. The various aspects and features described and illustrated in this specification can be applied individually wherever possible. These individual aspects, in particular those aspects and features described in the accompanying dependent claims, can be the subject of divisional patent applications. [Brief description of the drawings]

[0054] The invention will be elucidated on the basis of exemplary embodiments shown in the attached drawings.

[0055] [Figure 1] 1 is a schematic external view of an exposure apparatus according to an embodiment of the present invention. [Diagram 2] 1 is a schematic external view of a microscope or inspection apparatus according to an embodiment of the present invention; [Diagram 3] 1 is a schematic cross-sectional view of an embodiment of a charged particle blocking element according to the present invention; [Figure 4]1 illustrates a schematic representation of the blocking of charged particles by a charged particle blocking element. [Diagram 5] 1 is a schematic cross-sectional view of one embodiment of a portion of a charged particle blocking element according to the present invention. [Figure 6] 4 is a schematic cross-sectional view of another embodiment of a portion of a charged particle blocking element according to the present invention. [Figure 7] 7 is a second schematic cross-sectional view of the charged particle blocking element according to the embodiment of FIG. 6. [Figure 8] 1 is a schematic cross-sectional view of a charged particle blocking element provided with cooling channels according to an embodiment; [Figure 9] 1 is a schematic top view of an embodiment of a charged particle blocking element according to the present invention; [Figure 10A] 2 is a schematic top view of another embodiment of a charged particle blocking element according to the present invention; FIG. [Figure 10B] FIG. 10B is a schematic cross-sectional view taken along line VII-VII in FIG. 10A. [Figure 11] 1 illustrates a method for manufacturing a semiconductor device. [Figure 12] 1 illustrates diagrammatically a method for inspecting a target. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0056] 1 is a schematic external view of an example of an exposure apparatus 100 for projecting one or more charged particle beams onto a target 110. Such an exposure apparatus may be part of a charged particle multi-beam lithography system, a charged particle multi-beam inspection system, or a charged particle multi-beam microscope. In particular it may be an electron beam system, although the present teachings also apply to other types of charged particle.

[0057] 1 comprises a charged particle optical device with a charged particle source 101 for generating a charged particle macrobeam 111. The charged particle source 101 in this particular example is configured to generate a diverging charged particle macrobeam that is directed to a collimator lens 102 for focusing and / or collimating the charged particle macrobeam 111. In some embodiments, the charged particle source 101 is an electron source.

[0058] The charged particle optical device comprises an aperture array element 104 downstream of the collimator lens 102, which comprises an array of apertures 1041 for splitting the charged particle macrobeam 111 into a number of charged particle beams 112. The aperture array 104 comprises a charged particle blocking element according to the invention, which in this embodiment is a current limiting element. The charged particle blocking element comprises a substrate 1042 with an array of apertures 1041 and is provided with an absorbing layer 1043 comprising boron, carbon or beryllium. The absorbing layer 1043 is arranged on the surface of the substrate 1042 facing the charged particle source 101. As shown diagrammatically in FIG. 1, the collimated macrobeam 111 impinges on the aperture array element 104, in particular its absorbing layer 1043, which blocks a part of the collimated macrobeam 111 while forming a number of charged particle beams 112 by the part of the macrobeam that has passed through the aperture 1041. In the example of FIG. 1, only three beams 112 are shown for clarity, but the number of beams is typically in the range of hundreds, thousands, or tens of thousands.

[0059] Charged particle blocking elements according to the present invention have been found to be particularly advantageous when used as current limiting elements, particularly in conjunction with the above-described aperture array element 104. Alternatively or additionally, charged particle blocking elements may be used elsewhere in the device, as described below.

[0060] The charged particle optical device further comprises a modulation aperture array 105 towards the target 110 for generating a number of charged particle sub-beams 115 from each of the charged particle beams 112. A focusing lens array 103 (or a set of focusing lens arrays) is provided between the aperture array 104 and the modulation aperture array 105 for focusing the charged particle beams 112 onto corresponding apertures in a beam stop array 108 located downstream of the modulation aperture array 105.

[0061] In this example, the aperture array 105 is shown as generating three sub-beams 115, 116 from each charged particle beam 112. In practice, the number of sub-beams 115 generated from each charged particle beam 112 is typically much greater than three. In one embodiment, approximately 50 sub-beams (e.g., 49 sub-beams generated by a 7×7 aperture array) are generated from each charged particle beam 112. In other embodiments, 200 or more sub-beams may be generated.

[0062] Modulated aperture array 105 may also include charged particle blocking or current limiting elements according to the present invention, although this is not shown in detail in FIG.

[0063] The modulated aperture array 105 is part of the charged particle optical device and comprises an array of deflectors configured to individually deflect the charged particle sub-beams 116 so that they are blocked by the beam stop array 108, or to allow the charged particle sub-beams 115 to pass through corresponding apertures in the beam stop array 108 undeflected.

[0064] The beam stop array 108 comprises an array of apertures 1081 configured to allow the passage of the charged particle sub-beams 115 when they are not deflected by the modulation aperture array 105. The charged particle sub-beams 116 deflected by the modulation aperture array 105 are directed towards a surface of the beam stop array 108 facing the charged particle source 101 to be blocked by the beam stop array 108. In this example, the beam stop array 108 comprises a charged particle blocking element according to the invention, comprising a substrate 1082 with apertures 1081 and provided with an absorbing layer 1083 made of a material comprising boron, carbon or beryllium. The absorbing layer 1083 is arranged on a surface of the substrate 1082 facing the charged particle source 101 and receiving the sub-beams 116 to be blocked. As shown diagrammatically in FIG. 1, the absorbing layer 1083 is arranged close to and spaced apart from the apertures 1081 of the beam stop array 108.

[0065] The charged particle optical device in turn comprises a projection lens or projection lens array 109 for projecting the charged particle sub-beams 115 that have passed through the beam stop array 108 onto the surface of the target 110. The charged particle optical device may further comprise one or more scanning deflector arrays (not shown) for scanning the sub-beams 115 over the surface of the target 110 while exposing said target 110.

[0066] In a charged particle multi-beam lithography system, a charged particle multi-beam inspection system, or a charged particle multi-beam microscope, the target 110 is typically placed on top of a stage 120 that allows the target 110 to be accurately positioned and moved relative to the charged particle optical device.

[0067] As clearly shown in Fig. 1, the substrate 1042, 1082 with the absorbing layer 1043, 1083 is configured to block at least a part of the charged particle beam 111, 116 from the charged particle source 101, and at least a part of the blocked charged particle beam 111, 116 falls at least partially on the absorbing layer 1043, 1083 of the charged particle blocking element. Thereby, the total current of the charged particle beam above the charged particle blocking element is higher than the total current of the charged particle beam below the charged particle blocking element. The charged particle blocking elements, specifically the aperture array 104, the modulating aperture array 105 and the beam stop array 108 are current limiting elements of the exposure apparatus 1.

[0068] In some embodiments, the collimator lens 102, at least a part of it close to the aperture array 104, may comprise a charged particle blocking element according to the invention, comprising a substrate 1021 provided with an absorbing layer 1022 and with at least one aperture through which the macrobeam 111 passes. In the illustrated embodiment, the absorbing layer 1022 is arranged on the surface of the substrate 1021 facing the aperture array 104, since in use it can act as a charged particle source of backscattered charged particles from the part of the charged particle beam that does not pass through the aperture 1041 and / or of secondary electrons that may be generated in the charged particle optical device by the charged particle beam 111 impinging on the aperture array element 104, for example by these charged particles being backscattered and impinging on other components in the system.

[0069] The collecting lens array 103, at least a portion of it closest to the modulation aperture array 105, may also comprise a charged particle blocking element according to the present invention comprising a substrate 113 provided with at least one aperture and an absorbing layer 114 made of boron, carbon or beryllium. The absorbing layer 114 is disposed on a surface of the substrate 113 facing the modulation aperture array 105 and, in use, may act as a source of backscattered and / or secondary electrons that may be generated in the charged particle optical device when the charged particle beam 112 is incident on the modulation aperture array 105.

[0070] Furthermore, the charged particle blocking element can be used as a shutter 107 that is substantially horizontally movable between the charged particle source 101 and the collimator lens 102 and functions as a source shutter. In this case, the charged particle blocking element is typically not provided with an aperture. By moving it into the charged particle beam path, the charged particle beam from the charged particle source 101 is blocked, making it possible to temporarily block the charged particle beam without powering down the charged particle beam source, for example during positioning and / or replacement of elements downstream of the charged particle source.

[0071] The charged particle blocking element can also be used as a shutter 108 located between the modulation aperture array 105 and the beam stop array 108, functioning as a beam shutter. Such a shutter is applied to block one or more groups of the beams 115, 116, for example in case of a non-optimally functioning modulation aperture array 105. This shutter can be realized by a non-apertured charged particle blocking element, which can be placed in the charged particle beam path to block one or more groups of the charged particle beams 115, 116. Alternatively, the charged particle blocking element can be provided with one or more apertures that can selectively block one or more groups of the charged particle beams 115, 116 while allowing other groups of the charged particle beams 115, 116 to pass.

[0072] FIG. 2 shows a schematic representation of a charged particle inspection system or microscope, e.g., an electron microscope, with a charged particle blocking element according to the present invention. Such microscopes and inspection systems have a wide range of applications, e.g., in semiconductor device manufacturing. The apparatus comprises a charged particle source 201 generating a charged particle beam 202 and charged particle optics 203 projecting the charged particle beam 202 onto a target 210, also called a sample, to be inspected or analyzed. The target 210 is typically positioned on a stage (not shown) that is movable relative to the charged particle optics 203. The charged particle optics 203 comprises various charged particle optical elements and components, including electrostatic and / or electromagnetic lens elements for influencing the charged particle beam, as known in the art. In some systems, the charged particle beam 202 is split into a number of individual beams (not shown) that are directed towards the target. One or more different detectors 204, 205 are provided for detecting various signals 206, 207 resulting from the interaction of the charged particle beam with the target 210. Such signals include, for example, secondary electrons, Auger electrons, backscattered charged particles, X-rays, cathodoluminescence, and the like.

[0073] The inspection system further comprises a shutter element 10 realized by a charged particle blocking element according to the invention. The shutter element 10 is configured to temporarily block the charged particle source. Alternatively or additionally, the charged particle blocking element of the invention can be provided in the charged particle optics 203, for example as a current limiting element. Alternatively or additionally, the shutter element 10 may be configured to temporarily block the charged particle optics and / or the detector area from the target space.

[0074] Examples of known inspection systems and / or electron microscopes can be found in US Patent No. 7,732,762 B2, US Patent No. 6,844,550 B1, and ALEberle et al., "High-resolution, high-throughput imaging with a multibeam scanning electron microscope", Journal of Microscopy, Vol. 259, Issue 2, 2015, pp. 114-120. According to the above, in these systems the charged particle blocking element according to the invention may be used e.g. as a shutter downstream of the electron source or electron gun and / or as an aperture array, beam splitter or beam limiting aperture.

[0075] Various embodiments of a charged particle blocking element according to the invention are shown in Figures 3 to 10 and described below. The charged particle blocking element described with reference to Figures 1 to 2 may be a charged particle blocking element according to any one or more of these embodiments.

[0076] 3 is a schematic cross-sectional view of a charged particle blocking element 10 according to an embodiment. The charged particle blocking element 10 comprises a substrate 11 having a conductive surface on which an absorbing layer 13 is provided. In the illustrated embodiment, the conductive surface is provided by a conductive layer 14 applied to the surface of the substrate 11. The absorbing layer 13 is then applied onto the conductive layer 14. The absorbing layer 13 is advantageously a boron or boron nitride layer, although other materials can also be used, including for example carbon (C) or beryllium (Be). The substrate 11 can be a silicon substrate and the conductive layer 14 can be a molybdenum layer.

[0077] As discussed above, the thickness of the absorbing layer is important. Figure 4 shows, in a schematic way, the path of an electron impinging on a charged particle blocking element comprising a conductive substrate 11 provided with an absorbing layer 13. A similar situation applies to the element shown in Figure 3. An electron e- impinges on the surface of the charged particle blocking element 10'. When the electron e- impinges on the absorbing layer 13, it can be absorbed by this layer. Once absorbed, the electron enters the absorbing layer. The absorbing layer must be thick enough so that the electron is more likely to be absorbed by the absorbing layer than to be backscattered by the lower surface 12. To avoid charge build-up in the absorbing layer 13 as a result of electron absorption, it is necessary to remove the charge from the absorbing layer. As mentioned above, layers containing, for example, boron are generally poor conductors. If the layer is thin enough, the charge will pass through the absorbing layer and reach the surface 12 of the conductive substrate 11, which in this example is connected to electrical ground. The possibility of the charge passing through the absorbing layer to be transported to the conductive surface below decreases as the thickness of the absorbing layer increases. The inventors have found that the thickness of the absorbing layer should be several hundred nanometers, for example about 200 nm.

[0078] 5 is a schematic cross-sectional view of a charged particle blocking element 20. The charged particle blocking element can be used, for example, to block at least a portion of a charged particle beam from a charged particle source. The charged particle blocking element 20 can be used as a current limiting element, with an aperture 22 acting as a current limiting aperture. The charged particle blocking element 20 comprises a substantially flat substrate 21 with at least one aperture 22. The substrate 21 is provided with an absorbing layer 23 made of a material containing boron, carbon or beryllium. Preferably, the absorbing layer 23 is a coating of boron, boron nitride or silicon carbide. The absorbing layer 23 is configured, in use, to substantially cover an area on the substrate 21 including at least a portion of the substrate that faces towards the charged particle source 101, e.g., on the aperture array 104 and / or the beam stop array 108 of FIG. 1, or facing the aperture array 104 or the modulation aperture array 105, e.g., as part of the collimator lens 102 and / or the focusing lens array 103, respectively.

[0079] The substrate 21 according to this embodiment comprises a conductive material allowing the removal of charge from the absorbing layer 23. Such a substrate 21 is suitably connected in use via a connection 25 to a control or ground potential 26, allowing the charge of the absorbing layer 23 to be removed by electrical conduction through said substrate 21. It is noted that a conductive material in the sense of this embodiment may also comprise a highly doped semiconductor material. Thus, the substrate 21 may for example comprise a highly doped silicon wafer.

[0080] Figure 6 is a schematic cross-sectional view of a charged particle blocking element 30 according to another embodiment. The charged particle blocking element 30 comprises a substantially flat substrate 31 with at least one aperture 32. The substrate 31 is provided with an absorbing layer 33 made of a material comprising boron, carbon or beryllium. Preferably, the absorbing layer 23 is a coating of boron, boron nitride or silicon carbide. The absorbing layer 33 is configured to substantially cover an area on said substrate 31 including at least a portion of said substrate and may be configured in use in a similar manner as described for the charged particle blocking element of Figure 5.

[0081] The charged particle blocking element 30 according to this embodiment is provided with a conductive layer 34. The conductive layer 34 is disposed between the substrate 31 and the absorbing layer 33. In use, the conductive layer 34 is connected to a ground potential 36 or a control potential via a connection 35, as shown diagrammatically in the charged particle blocking element 30 with multiple apertures 32 in FIG. 7. Connecting the conductive layer 34 to the ground potential 36 allows charge to be removed from the absorbing layer 33 by electrical conduction through the conductive layer 34. The conductive layer 34 comprises, for example, molybdenum or chromium. Although only one aperture 32 is shown in FIG. 6, the charged particle blocking element may comprise multiple apertures 32, as shown in FIG. 7.

[0082] In particular, the charged particle blocking element 30 with a plurality of apertures 32, as shown diagrammatically in FIG. 7, desirably comprises a substrate 31 which is a readily available Si wafer, providing a very flat and mechanically robust substrate with a well-defined thickness.

[0083] Figure 8 shows another embodiment of a charged particle blocking element 40. The charged particle blocking element 40 comprises a substantially planar substrate 41 with at least one aperture 42, preferably a plurality of apertures 42. The substrate 41 is provided with an absorbing layer 43 of a material comprising boron, carbon or beryllium, preferably a coating of boron, boron nitride or silicon carbide. The absorbing layer 43 is configured to substantially cover an area on said substrate 41 including at least a portion of said substrate, and in use is typically configured in a similar manner as described for the charged particle blocking element of Figure 5.

[0084] The charged particle blocking element 40 according to this embodiment is provided with one or more cooling channels 45 for cooling the substrate 41. The cooling channels 45 are arranged in thermal contact with the substrate 41 and / or with another electrically and / or thermally conductive layer 46.

[0085] Another conductive layer 46 is disposed in contact with the absorptive layer 43 and the cooling channels 45 and may include a material having a high thermal conductivity to provide a thermal conduction path from the absorptive layer 43 to the cooling channels 45 .

[0086] Additionally or alternatively, the further conductive layer 46 may comprise a material having high electrical conductivity and provide a conductive path from the absorbing layer 43 and / or the conductive layer 44 disposed between the substrate 41 and the absorbing layer 43 to a cooling channel 45 which, in use, is connected to a ground potential 47.

[0087] As shown diagrammatically in Figure 8, the cooling channels 45 are disposed on the side of the substrate 41 away from the absorbing layer 43. However, the cooling channels 45 could also be disposed on the same side of the substrate 41 as the absorbing layer 43, preferably spaced away from the apertures 42. In such a configuration, the absorbing layer 43 could be disposed in direct contact with the cooling channels 45, without the need for a separate conductive layer 46 as in the embodiment of Figure 8.

[0088] Fig. 9 is a schematic top view of an embodiment of a charged particle blocking element 50 according to the present invention. The charged particle blocking element 50 comprises a substantially flat substrate 51 with an array 56 of apertures arranged in an array region 52. The substrate 51 is a silicon wafer provided with a coating 53 of molybdenum as a conductive layer. On top of the molybdenum coating 53, a coating 54 of boron is arranged as an absorbing layer. As shown diagrammatically in Fig. 9, the absorbing layer, specifically the boron coating 54, is arranged at a distance from the apertures of the aperture array 56. In particular, the boron coating 54 is arranged at a distance from the array region 52. The absorbing layer 54 may be arranged as one single region or may be provided by a plurality of regions separated by portions 55 of the conductive coating 53 that are not covered by the absorbing layer or coating.

[0089] In one embodiment of the present invention, the charged particle blocking element 50 is used as an aperture array element 104 for forming a plurality of charged particle beams from a macro beam, and in particular as an aperture array element 104 in a charged particle exposure system 100. An example of a cross section of a macro beam 111 on the charged particle blocking element 50 when used as an aperture array element 104 is shown by circle 57. As can be seen, most of the beam falls on the area covered by the absorbing layer 54. That is, most of the blocked portion of the charged particle beam strikes and is absorbed by the absorbing layer 54.

[0090] Figure 10A is a schematic top view of another embodiment of a charged particle blocking element 60 according to the present invention, and Figure 10B is a schematic cross-sectional view along line VII-VII of Figure 10A.

[0091] The charged particle blocking element 60 comprises a substantially flat substrate 61 with an array of apertures arranged in different array regions 62. The substrate 61 is a silicon wafer provided with a coating 63 of molybdenum as a conductive layer. On top of the molybdenum coating 63 a coating 64 of boron is arranged as an absorbing layer. As shown diagrammatically in Figures 10A and 10B, the absorbing layer 64 is arranged at a distance from the apertures of the aperture array. In particular, the boron coating 64 is arranged at a distance from the array regions 62. As shown diagrammatically in Figures 10A and 10B, the boron coating 64 also extends at least partially into the regions 65 between the array regions 62.

[0092] The absorbing layer 64 may be disposed as one unitary region, or may be provided by multiple regions separated by portions 66 of the conductive coating 63 that are not covered by the absorbing layer or coating.

[0093] The charged particle blocking element 60 may be used, for example, as an aperture array to split a charged particle macrobeam into multiple charged particle beams. In one embodiment of the invention, it is used in an aperture array element 104 of a charged particle exposure system as shown in Figure 1. An example of a cross-section of a macrobeam 111 on the charged particle blocking element 60 when used as an aperture array 104 is shown by circle 67. As can be seen, a large portion of the blocked beam is blocked by the absorbing layer 64.

[0094] 11 shows diagrammatically the steps of a method 80 for manufacturing semiconductor devices using the exposure apparatus described above. In a first step 81, a wafer is placed downstream of the charged particle optical apparatus. In a second step 82, processing of the wafer is performed, which includes projecting an image or pattern onto the wafer using a charged particle beam generated, shaped and / or modulated by the charged particle optical apparatus. In a third step 83, subsequent steps are performed to generate semiconductor devices from the processed wafer. Such subsequent steps are well known in the art.

[0095] 12 shows diagrammatically the steps of a method 90 for inspecting a target using the exposure apparatus or inspection system described above. In a first step 91, a target is placed downstream of a charged particle optical device, and in a second step 92, a charged particle beam generated and shaped by the charged particle optical device is directed towards the target. In a third step 93, charged particles transmitted, emitted and / or reflected by the target when the charged particle beam is incident on the target are detected. In a fourth step 94, subsequent steps are performed to inspect the target using data collected during the step of detecting the charged particles.

[0096] It should be understood that the above description is included to illustrate the operation of the preferred embodiment, and is not intended to limit the scope of the invention. From the above discussion, many variations will be apparent to those skilled in the art that are also within the scope of the invention.

[0097] Terms C1. A charged particle blocking element for blocking charged particles, the charged particle blocking element comprising a substrate, at least a portion of a surface of the substrate being provided with an absorbing layer comprising boron (B), carbon (C) or beryllium (Be), the absorbing layer being provided on a conductive surface.

[0098] C2. The charged particle blocking element of clause C1, wherein the absorbing layer has a thickness sufficient to prevent backscattering of charged particles from a portion of the substrate located below the absorbing layer and thin enough that the conductive surface receives the charge of the charged particles.

[0099] C3. The charged particle blocking element of clause C1 or C2, wherein the absorbing layer has a thickness between 100 nm and 500 nm.

[0100] C4. The charged particle blocking element of clause C3, wherein the absorbing layer has a thickness between 150 and 250 nm.

[0101] C5. The charged particle blocking element of any one of clauses C1 to C4, wherein the absorbing layer is a boron layer, a boron nitride layer, or a silicon carbide layer.

[0102] C6. The charged particle blocking element of any one of clauses C1 to C5, wherein at least a portion of the substrate is conductive.

[0103] C7. The charged particle blocking element of clause C6, wherein the substrate includes a connection for connecting at least a conductive portion of the substrate to a voltage source or ground potential.

[0104] C8. The charged particle blocking element of any one of clauses C1 to C7, wherein the substrate is provided with a conductive layer, the conductive layer being at least partially disposed between the substrate and the absorbing layer.

[0105] C9. The charged particle blocking element of clause C8, wherein the conductive layer comprises molybdenum (Mo) or chromium (Cr).

[0106] C10. A charged particle blocking element as described in clause C8 or C9, comprising a conductive connection portion connected to the conductive layer.

[0107] C11. The charged particle blocking element of any one of clauses C1 to C10, wherein the substrate comprises a silicon (Si) wafer.

[0108] C12. The charged particle blocking element of any one of clauses C1 to C11, wherein the substrate is provided with at least one aperture that allows the charged particles to pass therethrough.

[0109] C13. The charged particle blocking element of clause C12, wherein the substrate is provided with a plurality of apertures, the apertures configured to form one or more aperture arrays, each aperture array disposed in a corresponding array region of the substrate.

[0110] C14. The charged particle blocking element of clause C13, wherein the absorbing layer at least partially surrounds the array region.

[0111] C15. The charged particle blocking element of clause C13 or C14, wherein each array region is at least partially surrounded by an absorbing layer.

[0112] C16. The charged particle blocking element of any one of clauses C13 to C15, wherein an absorbing layer is further disposed at least partially within each array region.

[0113] C17. The charged particle blocking element of any one of clauses C12 to C16, wherein the absorbing layer is positioned spaced apart from the at least one aperture.

[0114] C18. A charged particle blocking element described in any one of clauses C1 to C17, wherein the charged particle blocking element comprises a cooling passage for cooling at least the substrate, preferably the cooling passage being arranged in thermal contact with the absorption layer and / or the substrate.

[0115] C19. The charged particle blocking element of clause C18, wherein the substrate is provided with another electrically and / or thermally conductive layer, the another electrically and / or thermally conductive layer being disposed in contact with the absorption layer and the cooling channels.

[0116] C20. A current limiting element for use in a charged particle exposure apparatus, the current limiting element comprising a substrate that is substantially opaque to charged particles, the substrate being provided with one or more apertures that pass the charged particles through the substrate from a first surface to a second surface of the substrate; an absorbing layer comprising boron (B), carbon (C) or beryllium (Be) is provided on at least a portion of the first surface; A current-limiting element, wherein an absorbing layer is provided on the conductive surface.

[0117] C21. The current-limiting element of clause C20, wherein the absorbing layer at least partially surrounds an area of ​​the first surface in which the one or more apertures are located.

[0118] C22. The current-limiting element of clause C20 or C21, wherein the absorbing layer is disposed spaced apart from the one or more apertures.

[0119] C23. A current-limiting element as described in any one of clauses C20 to C22, wherein the absorbing layer has a thickness sufficient to prevent backscattering of charged particles from a portion of the substrate located below the absorbing layer and thin enough that the conductive surface receives the charge of the charged particles.

[0120] C24. The current-limiting element of any one of clauses C20 to C23, wherein the absorbing layer has a thickness of 100 nm to 500 nm.

[0121] C25. The current-limiting element of clause C24, wherein the absorbing layer has a thickness of 150 nm to 250 nm.

[0122] C26. The current-limiting element of any one of clauses C20 to C25, wherein the absorbing layer is a boron layer, a boron nitride layer, or a silicon carbide layer.

[0123] C27. The current-limiting element of any one of clauses C20 to C26, wherein at least a portion of the substrate is conductive.

[0124] C28. A current-limiting element as described in any one of clauses C20 to C27, wherein the substrate is provided with a conductive layer, the conductive layer being at least partially disposed between the substrate and the absorbing layer.

[0125] C29. The current-limiting element of clause C28, wherein the conductive layer comprises molybdenum (Mo) or chromium (Cr).

[0126] C30. A current-limiting element as described in any one of clauses C27 to C29, comprising a conductive connection for connecting the conductive substrate or conductive layer to a voltage source or ground potential.

[0127] C31. The current-limiting element of any one of clauses C20 to C30, wherein the substrate comprises a silicon (Si) wafer.

[0128] C32. The current-limiting element of any one of clauses C20 to C31, further comprising a cooling channel for cooling at least the substrate, preferably the cooling channel being disposed in thermal contact with the absorbing layer and / or the substrate.

[0129] C33. The current-limiting element of clause C32, wherein the substrate is provided with another electrically and / or thermally conductive layer, the another electrically and / or thermally conductive layer being disposed in contact with the absorption layer and the cooling channel.

[0130] C34. A shutter element for blocking a charged particle beam, the shutter element comprising a substrate provided with an absorbing layer comprising boron (B), carbon (C) or beryllium (Be) at least in a portion thereof, the absorbing layer being provided on a conductive surface on the substrate.

[0131] C35. The shutter element of clause C34, wherein the absorbing layer has a thickness sufficient to prevent back scattering of charged particles from a conductive surface located below the absorbing layer and thin enough that the conductive surface receives the charge of the charged particles.

[0132] C36. The shutter element of clause C34 or C35, wherein the absorbing layer has a thickness between 100 nm and 500 nm.

[0133] C37. The shutter element of clause C36, wherein the absorbing layer has a thickness between 150 and 250 nm.

[0134] C38. A shutter element according to any one of clauses C34 to C37, wherein the absorbing layer is a boron layer, a boron nitride layer or a silicon carbide layer.

[0135] C39. The shutter element of any one of clauses C34 to C38, wherein at least a portion of the substrate is conductive.

[0136] C40. A shutter element according to any one of clauses C34 to C39, wherein the substrate is provided with a conductive layer, the conductive layer being at least partially disposed between the substrate and the absorbing layer.

[0137] C41. The charged particle blocking element of clause C40, wherein the conductive layer comprises molybdenum (Mo) or chromium (Cr).

[0138] C42. A charged particle blocking element as described in any one of clauses C39 to C41, comprising a conductive connection portion connected to a conductive portion or conductive layer of the substrate.

[0139] C43. An exposure apparatus for projecting a charged particle beam onto a target, the exposure apparatus comprising a charged particle optical device for forming a charged particle beam and projecting at least a part of the charged particle beam onto the target, the charged particle optical device comprising: a charged particle source for generating a charged particle beam; a charged particle blocking element according to any one of claims 1 to 19 capable of blocking at least a part of a charged particle beam from a charged particle source, a current limiting element according to any one of claims 20 to 33 configured to limit a charged particle current of the charged particle beam and / or a shutter element according to any one of claims 34 to 42 for temporarily blocking at least a part of the charged particle beam; An exposure apparatus comprising:

[0140] C44. The exposure apparatus of clause C43, wherein the absorbing layer of the charged particle blocking element, current limiting element, and / or shutter element is disposed on a surface of the substrate facing the charged particle source or facing the source of backscattered charged particles and / or secondary electrons.

[0141] C45. The exposure apparatus of clause C44, wherein the shutter element is arranged as a shutter for a charged particle source.

[0142] C46. An exposure apparatus according to any one of clauses C43 to C45, comprising a current limiting element according to any one of clauses C20 to C33, the current limiting element comprising an array of apertures configured to split the charged particle beam into a plurality of charged particle beams.

[0143] C47. An exposure apparatus as described in any one of clauses C43 to C46, ​​further comprising a modulation deflector for deflecting the charged particle beam into a charged particle blocking element, the modulation deflector and the charged particle blocking element being configured to allow the charged particle beam to pass through an aperture of the charged particle blocking element when the charged particle beam is not deflected by the deflector, or vice versa, to at least partially block the charged particle beam by the charged particle blocking element when the charged particle beam is deflected by the deflector.

[0144] C48. A charged particle lithography system comprising an exposure apparatus according to any one of clauses C43 to C47.

[0145] C49. A charged particle inspection system or a charged particle microscope comprising an exposure apparatus according to any one of clauses C43 to C48.

[0146] C50. A method for projecting a charged particle beam onto a target using an exposure apparatus as described in any one of clauses C43 to C49, the method comprising a step of blocking at least a portion of a charged particle beam from a charged particle source, wherein at least a portion of the blocked charged particle beam falls on an absorbing layer of a charged particle blocking element or a current limiting element.

[0147] C51. A method for manufacturing a semiconductor device using an exposure apparatus according to any one of clauses C43 to C49, the method comprising: positioning a wafer downstream of a charged particle optical device; processing the wafer, the processing comprising projecting an image or pattern onto the wafer using a charged particle beam generated, shaped and / or modulated by a charged particle optical device; performing subsequent steps to produce semiconductor devices using the processed wafer; The method includes:

[0148] C52. A method for inspecting a target using an exposure apparatus according to any one of clauses C43 to C49, comprising: positioning a target downstream of the charged particle optical device; directing the charged particle beam generated and shaped by the charged particle optical device toward a target; detecting charged particles transmitted, emitted and / or reflected by the target when the charged particle beam is incident on the target; performing a subsequent step to inspect the target using data collected during the step of detecting the charged particles; The method includes:

Claims

1. a substrate having an aperture for passing at least a portion of the charged particle beam from the charged particle source; an absorbing layer configured to absorb at least a portion of the charged particle beam from the charged particle source; the absorbing layer is disposed on a surface of the substrate and is spaced from an edge of the aperture to prevent scattering of a portion of the charged particle beam passing through the aperture; the material of the absorbing layer comprises carbon, boron (B), or beryllium (Be); at least a portion of the substrate includes a conductive layer configured to remove absorbed charge from the absorption layer; the apertures are configured to form one or more aperture arrays, each array disposed in a corresponding array region of the substrate; the absorber layer extends at least partially within and / or surrounds the or each array region of the substrate; Charged particle blocking element.

2. The charged particle blocking element of claim 1 , wherein the substrate comprises a connection for connecting the at least a portion of the substrate to a voltage source or ground potential.

3. The charged particle blocking element of claim 2 , wherein the conductive layer is connected to the voltage source or the ground potential.

4. The charged particle blocking element of any of claims 1-3, wherein the absorbing layer is a coating of boron, boron nitride, or silicon carbide.

5. The charged particle blocking element of any one of claims 1-4, wherein the absorbing layer has a thickness sufficient to prevent back scattering of the charged particles from a portion of the substrate located below the absorbing layer and thin enough that the conductive layer receives the charge of the charged particles.

6. The charged particle blocking element of any of claims 1-5, wherein the conductive layer is disposed at least partially between the substrate and the absorbing layer.

7. The charged particle blocking element of any of claims 1-6, wherein the conductive layer comprises molybdenum (Mo) or chromium (Cr).

8. The charged particle blocking element of any of claims 1-7, wherein the charged particle blocking element is a current limiting element arranged to limit a charged particle current of the charged particle beam.

9. The charged particle blocking element of claim 1 , further comprising a cooling channel for cooling at least one of the absorber layer, the substrate or the conductive layer.

10. The charged particle blocking element of claim 9 , further comprising a thermally conductive layer configured to provide a thermally conductive path from the absorbing layer to the cooling channel.

11. the cooling channels are disposed in thermal contact with the absorbent layer and / or the substrate; and / or 11. Charged particle blocking element according to claim 9 or 10, wherein the substrate is provided with a further electrically and / or thermally conductive layer.

12. A charged particle beam exposure apparatus, comprising: a charged particle optical device for forming a charged particle beam and projecting at least a portion of the charged particle beam onto a target; The charged particle optical device comprises: a charged particle source for generating the charged particle beam; A charged particle blocking element according to any one of claims 1 to 11, A charged particle beam exposure apparatus comprising:

13. A charged particle beam exposure apparatus, comprising: a charged particle optical device for forming a charged particle beam and projecting at least a portion of the charged particle beam onto a target; The charged particle optical device comprises: a charged particle source for generating the charged particle beam; a charged particle blocking element; The charged particle blocking element comprises: a substrate having an aperture for passing at least a portion of the charged particle beam from the charged particle source; an absorbing layer configured to absorb at least a portion of the charged particle beam from the charged particle source; the absorbing layer is disposed on a surface of the substrate and is spaced from an edge of the aperture to prevent scattering of a portion of the charged particle beam passing through the aperture; the material of the absorbing layer comprises carbon, boron (B), or beryllium (Be); at least a portion of the substrate includes a conductive layer configured to remove absorbed charge from the absorption layer; the apertures are configured to form one or more aperture arrays, each array disposed in a corresponding array region of the substrate; the absorber layer extends at least partially within and / or surrounds the or each array region of the substrate; Charged particle beam exposure device.

Images