Beam patterning device with beam absorbing structure

Abstract

To improve the layout of a PD device to improve removal of charge associated with blocked beamlets within the PD device.SOLUTION: A multi-beam pattern definition device 7 for use in particle beam processing or an inspection device includes an aperture array device 701 irradiated with a beam of charged particles and passing the beam through a plurality of apertures to form corresponding beamlets, and formed according to a plurality of sets of the plurality of apertures arranged in respective aperture arrangements, and an absorber array device 702 having a plurality of holes configured to pass beamlets formed by a subset of the plurality of apertures. The absorber array device includes a charged particle absorbing structure 724 including an absorbing region surrounded by a raised region and configured to absorb charged particles impinging at locations corresponding to other apertures of the aperture array device.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] This application claims the benefit of Paris Convention priority of European Patent Application No. 21191090.6, filed August 12, 2021, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to a multi-beam pattern definition device (hereinafter referred to as "PD device") for use in a particle beam processing or inspection device, the device comprising several components including an aperture array device adapted to be irradiated by a beam of charged particles, in particular electrons, and to pass the beam through a plurality of apertures to form a corresponding number of beamlets, the plurality of apertures being defined to form the corresponding number of beamlets. [Background technology]

[0003] PD devices of the above type and charged particle multi-beam processing apparatuses including such PD devices are described in commonly assigned U.S. Patent Nos. 6,768,125, 8,546,767, and 9,269,543, the teachings of which are incorporated herein by reference.

[0004] The above-mentioned documents describe charged particle lithography and processing methods and devices called PML2 (short for "Projection Mask-Less Lithography"); some documents by the applicant describe processing devices called eMET (short for "electron multi-beam Mask Exposure Tool"). These devices implement the multi-beam writing concept and use a programmable aperture plate system (APS) as the PD device for structuring particle beams extracted from a single source of charged particles.

[0005] PD devices include aperture array devices, hole array devices, and deflection array devices, and according to US 8,546,767 may comprise "multiple multi-beam arrays" comprising multiple arrays of apertures, since an aperture array device (AAD) comprises at least two sets of apertures, where each set comprises a plurality of apertures arranged in a (substantially) regular arrangement on the AAD, and the arrangements of these two or more sets are at least partially interlaced (shifted with respect to each other by a predetermined interval), and the apertures of different sets—at least in the regions where the arrangements interlace (aperture arrangement interlace regions)—are offset with respect to each other by a displacement that (substantially) corresponds to a common displacement vector. Correspondingly, and as a means of selecting one set from the multiple sets of apertures, the hole array device includes a plurality of holes formed for the paths of at least a subset of the beamlets formed by the apertures of the AAD, and in at least a region corresponding to the aperture arrangement interlace region, the hole array device includes a plurality of holes arranged in a substantially regular arrangement corresponding to the arrangement of one set of the multiple sets of apertures in that region, while on the other hand, the hole array device lacks holes (and therefore is opaque (non-transparent) therein) in positions corresponding to the apertures of one or more other sets of apertures.

[0006] Furthermore, a deflection array device, for example in the form of a so-called blanking plate, can often be present as an additional separate component of the PD device. The deflection array device has a plurality of blanking holes positioned so that each of the beamlets formed in the AAD and passed by the hole array device passes (traverses) one of the blanking holes along its nominal path, and the deflection array device also includes a plurality of electrostatic deflection electrodes, each associated with one blanking hole and configured to deflect (deviate) the beamlet passing through the respective blanking hole by an amount sufficient to deviate the beamlet from its nominal path when an activating voltage is applied to the electrode.

[0007] Further, advantageously, positioning devices may be provided that can position the AAD to adjust the position of the aperture array device relative to the hole array device and the deflection array device, the positioning devices being configured to selectively bring one or a selected set of the sets of apertures of the AAD into alignment with the holes of the hole array device and the blanking array device such that the apertures, holes (of the hole array device) and blanking holes are aligned at least in the aperture arrangement interlace region. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] US6,768,125 [Patent Document 2] US8,546,767 [Patent Document 3] US$9,269,543 Summary of the Invention [Problem to be solved by the invention]

[0009] While the above configuration has proven highly useful, the inventors have recognized that problems may arise during the use of PD devices in certain circumstances. In an aperture array device, a subset of beamlets are blocked by the bulk (non-aperture) portion of the aperture array device. Interaction of the beamlets (of the aforementioned charged particles) with the bulk portion of the aperture array device can often result in the generation of secondary particles, such as electrons. While some of the secondary particles will remain within the bulk material, some may be emitted from the bulk material at angular directions covering a polar angle range of 0 to 90° and an azimuthal (azimuth) angle range of 0 to 360°. Here, the polar angle is the angle between the emission direction and the surface normal of the aperture array device, essentially pointing from the aperture array device toward the closest AAD. For secondary particles, their angular distribution will typically follow a cosine law (with respect to polar angle) with a maximum at a polar angle of 0°. Such emission of secondary particles will typically occur within a few microns around the site where the beamlets impinge on the surface of the hole array device (with an energy of 5 keV for electron beamlets).

[0010] When charged secondary particles (especially electrons) are generated, they will, primarily intuitively, deposit and accumulate charge at the AAD and possibly other locations on the hole array device. Charge accumulation is facilitated by the locally low electrical conductivity at these locations, which prevents the charge from flowing or dissipating to electrical ground. The accumulated charge will generate an electric field that can deflect (deviate) the (primary) beamlets, which can cause undesired beamlet misalignment at the target surface and, as a result, reduce pattern fidelity. This can also be accompanied by locally low electrical conductivity caused by surface contaminants on the aperture array device or hole array device. Such contaminants can be caused, for example, by particles or manufacturing process residues, or by the decomposition of residual gas molecules (mainly those containing carbon) by primary beamlet particles and subsequent deposition (of carbon-containing solid materials).

[0011] In view of the above, it is an object of the present invention to improve the layout of a PD device to overcome the above possible problems, in particular to improve the removal of charged particles and associated charges of beamlets that are blocked within the PD device. [Means for solving the problem]

[0012] According to a first aspect of the present invention, there is provided a multi-beam pattern definition device for use in a particle beam processing or inspection system. the multi-beam pattern definition device is adapted to be illuminated by a beam of charged particles and to pass the beam through a plurality of apertures to form a corresponding number of beamlets (the number of apertures); The multi-beam pattern definition device an aperture array device on which the plurality of apertures are formed, the aperture array device including at least two sets of apertures, each set including a plurality of apertures transmissive to the beam, the apertures of each set being arranged in a substantially regular aperture arrangement on the aperture array device, the aperture arrangements of the sets being at least partially interlaced, the aperture arrangements constituting mutually equivalent arrangements offset with respect to each other by respective displacement vectors at least in a region where the aperture arrangements interlace (hereinafter referred to as an "aperture arrangement interlace region"); and an absorber array device positioned downstream of the aperture array device and having a plurality of holes configured to pass beamlets formed by at least a subset of the apertures; Including, The absorber array device includes a charged particle absorption structure including an absorption region surrounded by an absorber flank that is elevated (raised) relative to the absorption region and configured to absorb charged particles impinging on the absorption region, the absorption region being positioned at positions corresponding to apertures of at least one of the sets of apertures in at least an area corresponding to the aperture arrangement interlace area, and the plurality of holes of the absorber array device are arranged in a substantially regular arrangement in the area corresponding to the aperture arrangement of at least one other of the sets of apertures of the aperture array device (form 1). DETAILED DESCRIPTION OF THE INVENTION

[0013] (Mode 1) See the first aspect of the present invention above. (Feature 2) In the multi-beam pattern definition device of feature 1, a deflection array device having a plurality of blanking holes arranged such that each of the beamlets passes through one of the plurality of blanking holes along a nominal path; Preferably, the deflection array device includes a plurality of electrostatic deflection electrodes, each associated with one blanking hole and configured to deflect the beamlet passing through the respective blanking hole by an amount sufficient to deviate the beamlet from its nominal path when an activation voltage is applied to the electrode. (Feature 3) In the multi-beam pattern definition device of feature 1 or 2, Preferably, the charged particle absorption structure includes a plurality of charged particle absorber devices, each of which is positioned at a position on the absorber array device corresponding to a location where one of the beamlets impinges and is configured to absorb the charged particles of that beamlet. (Feature 4) In the multi-beam pattern definition device of any one of features 1 to 3, The charged particle absorber device is preferably configured as a depression or blind hole formed in the surface of the absorber array device, the depression preferably extending along the corresponding direction of the beamlets impinging on the depression. (Feature 5) In the multi-beam pattern definition device of feature 4, Preferably, the depressions or blind holes have a depth to width ratio greater than two. (Form 6) In the multi-beam pattern definition device of any one of Forms 1 to 5, The charged particle absorber device is preferably configured as an electrode-like structure protruding from a surface of the absorber array device. (Feature 7) In the multi-beam pattern definition device of feature 6, Preferably, the electrode-like structures have a depth to width ratio greater than two. (Feature 8) In the multi-beam pattern definition device of any one of features 1 to 7, The charged particle absorption structure preferably comprises a trench or hole having a width that is a multiple of two greater than the lateral size of an aperture of the aperture array device. (Feature 9) In the multi-beam pattern definition device of any one of features 1 to 8, Preferably, the absorber array device further includes a conductive coating formed on at least the side thereof facing the aperture array device. (Form 10) In the multi-beam pattern definition device of any one of Forms 1 to 9, It is preferable that at least one of the aperture array device and the absorber array device is movable in a plane transverse to the propagation direction of the beam to adjust the relative position of the aperture array device with respect to the absorber array device, and is configured to selectively bring any selected set of the sets of apertures of the aperture array device into alignment with the multiple holes of the absorber array device at least in the aperture arrangement interlace region. (Feature 11) In the multi-beam pattern definition device of feature 10, a positioning device for positioning at least one of the aperture array device and the absorber array device to adjust the relative position of the aperture array device with respect to the absorber array device; Preferably, the positioning device is configured to selectively bring a selected set of the sets of apertures of the aperture array device into alignment with the plurality of holes of the absorber array device in at least the aperture arrangement interlace region. (Form 12) In the multi-beam pattern definition device of any one of Forms 1 to 11, Preferably, the absorber array device is positioned downstream of the aperture array device at a predetermined distance from the aperture array device.

[0014] The above object is achieved by a multi-beam pattern definition apparatus of the type described in the introduction, which apparatus comprises an aperture array device and an absorber array device, preferably located downstream of the aperture array device and preferably arranged at a predetermined distance relative to the aperture array device, the absorber array device comprising a charged particle absorbing structure configured to absorb some of the charged particles of the beamlets formed by the aperture array device and impinging on the absorber array device.

[0015] More specifically, the aperture array device, also referred to as an "aperture plate", includes at least two sets of apertures that are transparent to the beams (so that the beams traverse (pass) through the apertures) of the aperture array device; each set of apertures includes a plurality of apertures arranged in a substantially regular arrangement in the aperture array device, and the arrangements of these sets ("aperture arrangements") are at least partially interlaced (arranged shifted by predetermined intervals relative to each other), and the apertures of different sets are offset (shifted) relative to each other by their respective displacement vectors, at least in the interlaced regions (aperture arrangement interlaced regions) of the (aperture) arrangements. The absorber array device has a plurality of holes configured for the passage of at least a subset of the beamlets formed by the apertures, but also includes charged particle absorbing structures including absorbing regions surrounded by absorber flanks, as already described, which are elevated (raised or raised) relative to the absorbing regions so as to absorb charged particles impinging on these absorbing structures, in particular the absorbing regions; these absorbing regions are positioned at positions corresponding to the apertures of at least one set of the sets of apertures in at least a region corresponding to the aperture arrangement interlace region; whereas the holes of the absorber array device are arranged in a substantially regular arrangement corresponding to the aperture arrangement of at least one other set of the sets of apertures in the region. In typical embodiments, the holes (of the absorber array device) correspond to the apertures of one set of the sets of apertures, and the absorber structure is configured to remove / absorb particles that traverse (pass through) the aperture array device through the apertures of all other sets of apertures.

[0016] Thus, the apertures are positioned according to multiple sets that constitute (implement) geometrically equivalent "aperture arrangements," at least in the aperture arrangement interlace region. (Note that in this document, the term "multiple" does not simply mean that there is a plurality of aperture arrangements, etc., but that there is a plurality of interlaced aperture arrangements, etc.) The (aperture arrangement) interlace region will typically extend over a significant portion of the area of ​​each aperture arrangement, i.e., over a majority, usually the majority, of that area, so that all that will remain will be, for example, a few rows of apertures at some or all of the edges of the aperture arrangement area. Each of the aperture arrangements is associated with a different displacement vector (relative to some arbitrary reference point, such as the central aperture of the first aperture arrangement); it is clear that the displacement vector, which describes the offset of one aperture arrangement relative to another of the aperture arrangements, is substantially uniform for all apertures of the same aperture arrangement, at least in the aperture arrangement interlace region.

[0017] The apertures of an aperture arrangement are arranged according to a substantially regular arrangement, as described above. Here, a regular arrangement means that the nominal locations of the apertures follow a regular grid on the surface of the aperture array device; for example, the grid can be a square grid, a rectangular grid, a hexagonal grid, etc. Each arrangement is substantially regular in that the locations of the individual apertures may deviate from their strictly regular grid nominal locations by small deviations (where "small" means at least an order of magnitude smaller than the inter-aperture distance between apertures in the same arrangement) and / or the arrangement may include a small number of apertures that do not fit into the regular grid (where "small" means at least an order of magnitude smaller than the total number of apertures in the arrangement). Such small deviations may be provided, for example, to allow for correction of imaging aberrations that vary over the area of ​​the aperture array device, predictable distortions in the device, etc. A displacement vector between arrangements is said to be substantially uniform if the offset (shift) between corresponding apertures in the two arrangements is the same, ignoring the small deviations mentioned above, except for a small number of apertures that do not fit into a regular grid that should not be considered in this regard. Any two arrangements that differ by such a substantially uniform displacement vector, at least in the interlaced region (of the aperture arrangements), are referred to herein as "equivalent arrangements."

[0018] Further, a positioning arrangement is advantageously provided for positioning the aperture array device and / or the absorber array device for adjusting the relative position of the aperture array device with respect to the absorber array device, the positioning arrangement being configured to selectively bring a selected set of the plurality of sets of apertures of the aperture array device into alignment with the plurality of holes of the absorber array device at least in said aperture arrangement interlace region.

[0019] In many embodiments of the present invention, the multi-beam pattern definition device may also include a deflection array device, also referred to as a blanking plate, having blanking holes positioned such that each beamlet passes through one of the blanking holes along its nominal path. The deflection array device includes a plurality of electrostatic deflection electrodes, each associated with a blanking hole and configured to deflect a beamlet passing through a corresponding blanking hole by an amount sufficient to deviate the beamlet from its nominal path when an activating voltage is applied to the corresponding electrode. This component is advantageous for use in certain writing methods employing this type of blanking.

[0020] In many exemplary embodiments of the present invention, it will be advantageous for the charged particle absorption structure to include a plurality of charged particle absorber devices, each device positioned at a location in the absorber array device corresponding to where one of the plurality of beamlets impinges (i.e., corresponding to one aperture in the aperture array device) and configured to absorb the charged particles of that beamlet.

[0021] Furthermore, the charged particle absorbers may be configured (embodied) as recesses or blind holes formed in the surface of the absorber array device, typically oriented towards the aperture array device. Preferably, these recesses may extend along the respective direction of the beamlets impinging on them. The recesses or blind holes may preferably have a depth to width ratio (aspect ratio) of 2 or more, for example 3 or more, or even 4 or more.

[0022] In one advantageous group of embodiments of the present invention, the charged particle absorber devices may be configured (embodied) as protruding structures (also called shield electrodes) formed on a surface of the absorber array device (in particular on the surface facing the aperture array device). These electrode-like structures protruding from the surface may preferably have a depth-to-width ratio of 2 or more, for example 3 or more, or even 4 or more.

[0023] In another advantageous group of embodiment(s) (or possibly in combination with the above groups), the charged particle absorption structure may comprise trench(es) and / or holes having a width that is a multiple of two (again, this multiple may be two or more, for example three or more, or even four or more) greater than the lateral size of the apertures of the aperture array device.

[0024] Furthermore, the absorber array device may advantageously include a conductive coating formed at least on its side pointing towards the aperture array device (ie at least on the absorber flanks).

[0025] Furthermore, the aperture array device and / or the absorber array device may be configured to be movable in a plane transverse to the propagation direction of the particle beam, allowing adjustment of the relative position of the aperture array device with respect to the absorber array device. This allows for the selection of any one of the multiple sets of apertures of the aperture array device. To achieve such a suitable method of position adjustment, a positioning device or arrangement may be provided for positioning at least one of the aperture array device and the absorber array device to adjust the relative position of the aperture array device with respect to the absorber array device. The positioning device is configured to selectively bring a selected set of the multiple sets of apertures of the aperture array device into alignment with the multiple holes of the absorber array device at least in the aperture arrangement interlace region. Advantageously, the distance between the aperture array device and the absorber array device is appropriately selected to allow free relative movement therebetween; a typical value of this distance is on the order of 0.5 mm to several mm, preferably 1 to 2 mm.

[0026] In the following, exemplary and non-limiting embodiments, as illustrated in the drawings, will be discussed to further explain the present invention. [Brief explanation of the drawings]

[0027] [Figure 1] 1 is a longitudinal cross-sectional view of an example of a particle beam exposure apparatus suitable for the present invention; [Figure 2] FIG. 1 is a plan view of an example of a PD system. [Figure 3] Side view of the PD system of Figure 2, shown partially in cross section (right half of the figure). [Figure 4] Cross-sectional view of a detail of an example of a PD setup with a three-plate structure: the AAD configured (embodied) as an aperture plate contains two sets of apertures; the first set of apertures is activated, while the second set is blocked in the hole array device. [Figure 5] FIG. 2 is a plan view of a portion of an aperture plate of an example PD system of the present invention. [Figure 6] A detail of Figure 4. This also shows the possible generation of charged secondary particles and the subsequent accumulation of charge at various locations on the aperture array device and hole array device. [Figure 7] 1 is an embodiment of the present invention (only a portion of a PD system is shown) comprising an absorber array device having blind holes and a conductive thin film formed in its upstream surface. [Figure 8] A detail of Figure 7 showing the improved behavior of beamlet propagation by the absorber array device. [Figure 9] FIG. 8 is a plan view of the absorber array device of FIG. 7 (only a portion corresponding to FIG. 7 is shown). [Figure 10] Another embodiment of the present invention (only a portion of the PD system is shown) has a shielding electrode formed on the upstream surface of the hole array device. [Figure 11] FIG. 11 is a plan view of the absorber array device of FIG. 10 (only a portion corresponding to FIG. 10 is shown). [Example]

[0028] In the following, we first discuss the technical background of the present invention—insofar as it pertains to exemplary embodiments of the present invention—and then present some exemplary embodiments of the present invention in detail.

[0029] The detailed discussion of exemplary embodiments of the present invention provided below discloses the basic idea and further advantageous developments of the present invention. It should be clear to those skilled in the art to combine any number or all of the embodiments discussed herein as deemed suitable for a particular application of the present invention. Throughout this disclosure, terms such as "advantageous," "exemplary," or "preferred" refer to elements or dimensions that are particularly suitable (but not essential) for the present invention or an embodiment thereof, and can be modified, unless explicitly required, if deemed suitable by those skilled in the art. It is understood that the present invention is not limited to the following embodiments or the specific layout of the PD system, which are merely representative of one possible application of the present invention, are provided for illustrative purposes, and merely present preferred embodiments of the present invention; also, embodiments of the present invention are suitable for other types of processing systems that use a multi-beam setup for target exposure. Within the scope of this disclosure, terms relating to the vertical (perpendicular) direction or vertical propagation, such as "up" or "upstream" / "downstream," should be understood with respect to the direction of the beam considered to travel downward along the longitudinal direction ("vertical axis"). This normal axis is further considered to be the same as the Z direction, which is intersected by the X and Y directions.

[0030] Charged Particle Multi-Beam System

[0031] A schematic overview of an example of an eMET system's charged particle multi-beam mask exposure tool (mask writer) 100 of the type employing embodiments of the present invention is shown in FIG. 1. In the following, only the details necessary to disclose specific embodiments of the present invention so that one skilled in the art can practice each are provided; for clarity, components are not drawn to scale in FIG. 1. In particular, the lateral width of the particle beam is exaggerated; for further details, see U.S. Patent Nos. 6,768,125, 8,546,767, and 7,781,748, the teachings of which regarding the overall layout of particle beam and PD devices are incorporated herein by reference.

[0032] A suitable source is used in the system 100 to generate the electron beam. In a variant, the beam can be constituted (embodied) by other charged particles, in particular positively charged ions using a suitable ion source. A particle-optical illumination system forms a wide beam from the beam, which illuminates a PD device having a regular array of apertures for defining the beam pattern to be projected onto the target surface. Each aperture defines a small beam, hereinafter generally referred to as a "beamlet," whose passage through an aperture can be controlled to allow ("switch on") or effectively deactivate ("switch off") the particles of the beam to pass through the apertures and / or subsequent magnifying charged particle projection optics towards the target.

[0033] The beamlets traversing the aperture array form a patterned particle beam, represented by the spatial arrangement of the apertures and containing information about the on / off definitions for the individual beamlets. The patterned beam is then projected onto a target (e.g., a mask blank or semiconductor wafer substrate) by a demagnified charged particle optical projection system, thus forming an image of the apertures at the target from which the corresponding beams are not deflected, exposing or modifying the target at the irradiation location. The images formed by the beamlets projected onto the substrate form a "pattern image," which is exposed along a straight path ("stripe") on a substrate that is mechanically moved in one direction; the (large-scale) movement of the substrate is usually achieved by continuous movement of the target stage, sometimes simultaneously by fine adjustment of the projection system. The direction of image movement relative to the stage is also referred to as the (main) scan direction. Additional scanning of the beam in a direction perpendicular to the main scan direction may be performed only within a small lateral range to compensate for lateral step motion errors of the scan stage and / or to include a (limited) number of parallel pixel rows, as described in more detail, for example, in my U.S. Pat. No. 9,053,906, the disclosure of which is incorporated herein by reference.

[0034] The main components of the apparatus 100—in this example, as viewed in the direction of the beams lb and pb, which extend vertically downward in FIG. 1 —are an illumination system 101, a PD system 102, a projection system 103, and a target station 104 having a target or substrate 14. The charged particle optical systems 101 and 103 are constructed (implemented) using electrostatic and / or electromagnetic lenses. The charged particle optical parts 101, 102, 103 and the target station 104 of the apparatus 100 are contained within a vacuum housing (not shown) that is maintained at a high vacuum to ensure unimpeded propagation of the beams lb and pb along the optical axis of the apparatus.

[0035] The illumination system 101 includes a charged particle illumination optical system, which is embodied, for example, by an electron or ion source 11, an extractor structure that defines the position of the virtual source, a general-purpose blanker 12 that can also be used as a particle filter when using an ion beam, and a particle-optical condenser lens system 13.

[0036] In the illustrated embodiment, the particle source 11 emits energetic electrons with a suitable kinetic energy, e.g., 5 keV; in other embodiments, hydrogen ions or Ar ions with a defined (kinetic) energy, typically a few keV (e.g., 5 keV in the PD system 102), with a relatively small energy spread, e.g., ΔE=1 eV. + Other charged particles, such as ions, primarily of a particular species, may be used. A velocity / energy dependent filter (not shown) may be provided to filter out other unwanted particle species that may also be produced in source 11; a filter may also be used to blank the beam as a whole during repositioning of the beamlets. A condenser lens system 13 forms a wide-area (large cross-section), substantially telecentric beam ("illuminating beam") lb from the charged particles emitted from source 11.

[0037] Beam lb then illuminates a blanking device, which together with the devices required to maintain its position (not shown) form PD system 102. PD system 102 is described in more detail below with reference to FIGS. 2-4. The PD device is held at a specific position in the path of beam lb, so that beam lb illuminates the aperture array pattern formed by a plurality of apertures 21. As noted above, each aperture can be "switched on" or "switched off." In the "switched on" or "open" state, an aperture allows beamlets passing through it to reach the target; in this case, the aperture is said to be transmissive (transparent) to the incident beam. Otherwise, the aperture is "switched off" or "closed," in which case the beam path of the corresponding beamlet is affected so that the beamlet is absorbed or otherwise removed from the beam path (e.g., by a deflection electrode to which a transverse voltage is applied; see beamlet b2 in Figure 4) before it can reach the target; therefore, the aperture is substantially non-transparent or opaque to the beam.

[0038] The pattern of switched-on apertures is selected according to the pattern to be exposed on the substrate, because these apertures are the only parts of the PD device that are transparent to the beam lb and therefore form the patterned beam pb that emerges from the aperture (i.e., below the PD system 102 in FIG. 1 ). The architecture and operation of the PD device, particularly its blanking plates, are discussed in detail below. While FIG. 1 shows only five beamlets in the patterned beam pb, it will be apparent that the actual number of beamlets is much higher, typically on the order of thousands or even millions; the second-left beamlet shown is switched off, so that it is deflected inside the PD device 102 and absorbed in the stop plate 17 located at or near the second crossover c2 of the charged particle projection optics; the other switched-on beamlets pass through the central hole in the stop plate 17 and are thus projected onto the target.

[0039] The pattern represented by the patterned beam pb is projected by a charged particle optical projection system 103 onto a substrate 14 (such as a 6" (inch) mask blank with a resist coating); switched-off beamlets are absorbed at a stop plate 17 so that only switched-on beamlets form images of the switched-on apertures. The projection system 103 performs a reduction of, for example, 200:1, as realized by the applicant. The substrate 14 can be, for example, a 6" mask blank or a nanoimprint 1x mask or master template coated with a resist layer in the case of an eMET type system, while in the case of a PML2 system the substrate 14 can be a silicon wafer coated with a particle-sensitive resist layer. The substrate 14 is held and positioned by a substrate stage (not shown) of the target station 104.

[0040] The projection system 103 is, for example, composed of two consecutive charged particle optical projector sections with crossovers c1 and c2, respectively. The particle optical lenses 30, 31 (e.g., including one electrostatic multi-electrode acceleration lens 30 and two magnetic lenses 31) used to implement the projectors are shown only symbolically in FIG. 1 , since the technical implementation of electrostatic imaging systems is well known in the prior art; in other embodiments of the present invention, magnetic and / or electromagnetic lenses may also be included as appropriate. The first projector section images the plane of the apertures of the PD device to generate an intermediate image, which is then imaged onto the substrate surface by the second projector section. Both the first and second sections employ demagnification imaging via crossovers c1 and c2; therefore, the intermediate image is inverted, while the final image generated on the substrate is upright (non-inverted). The demagnification ratio is approximately 14:1 for both stages, resulting in an overall demagnification ratio of 200:1. A demagnification of this order is particularly suitable for lithography setups, in order to shelve the miniaturization issues for PD devices. Charged particle optical lenses consist primarily of electrostatic electrodes, although magnetic lenses can also be used.

[0041] Further details of charged particle optical systems can be found in the prior art cited above.

[0042] Deflection means 16 are provided in one or both projector sections as a means for introducing small lateral shifts into the image, i.e., along a direction perpendicular to the optical axis cx. Such deflection means can be configured (embodied) as a multipole electrode system, for example, as discussed in U.S. Pat. No. 6,768,125. Additionally, axial magnetic coils can be used to cause pattern rotation in the substrate plane, if necessary. The lateral deflection is typically much smaller than the lateral width of the patterned beam itself, often on the order of several times the width of a single beamlet or the distance between adjacent beamlets, but still at least one order of magnitude less than the beam width (it is understood in this sense that the lateral distance between beamlets is much smaller than the total width of the beam bp).

[0043] By using a pattern formed on the PD device 102, any beam pattern can be generated and transferred onto a substrate.

[0044] PD System and Plate Architecture

[0045] Figures 2 and 3 illustrate one embodiment of the PD system 102 of the apparatus 100. Specifically, Figure 2 shows a plan view, and Figure 3 shows a combined side view and longitudinal cross-section. Figure 4 is a detail of the cross-section of Figure 3, showing a cross-section of the plates of the PD system 102 along the paths of five beamlets (five other prospective beamlets are internally excluded) traversing the PD system 102.

[0046] The PD system 102 includes multiple plates 22 mounted in a stacked configuration, forming a composite device whose components perform the respective functions, including those for the aperture plate 201, beam selection plate 202, and blanking plate 203. Additional component plates, such as adjustment plates (not shown; see U.S. Pat. No. 6,768,125) for individual fine adjustment of beamlet paths, may also be included. Each plate 22 is embodied as a semiconductor (particularly silicon) wafer whose structures are formed by microstructuring techniques known in the art, specifically as a membrane portion formed in the central region of the plate, representing the PD field pf with multiple holes, symbolically indicated by cross-hatching in FIG. 2 . The lithography beam traverses the plates through successive holes (upper and lower) in the PD field pf, which will be further described below.

[0047] The plates 22 are held by chucks 23, which are configured as known types of piezoelectric actuators or nanopositioning elements and attached to corresponding chucks by flexure joints and positioned relative to each other by actuator devices 241, 242, 243 fixed to a support structure 24 of the PD system. In the vertical direction, the chucks are connected using slidable bearings 25. The plates 22 and chucks 23 are preferably made of the same material, for example silicon, or of a material with the same thermal expansion behavior in the operating temperature range. The chuck also provides a power supply for the blanking plate 203; for clarity, electrical lines are not shown.

[0048] The plate 22 may also be provided with reference marks 26 for defining the reference beams. The shape of the reference beam rb is defined, for example, in a hole formed in one of the plates 22, e.g., aperture plate 201, while a corresponding hole in the other plate has a width sufficient to allow the radiation of the reference beam to pass. The reference beam is then imaged together with the patterned beam pb; however, unlike the patterned beam, the reference beam does not reach the substrate 41 but is instead measured in an alignment system (see U.S. Pat. No. 7,772,574). Furthermore, the chuck 23 may have alignment holes 236 that serve as alignment markers for the relative positioning of the chucks 23 and the plates 22 they hold.

[0049] The thickness of the membrane portion of each plate 22 is approximately 30-100 μm; the membrane of the blanking plate may be thicker if appropriate for better heat conduction. The frame portion of the plates is significantly thicker, on the order of 0.750 mm. The mutual distance between the plates is on the order of 0.5 to several mm. It should be noted that in FIG. 4, the dimensions on the vertical axis (z-axis parallel to the optical axis of the device) are not to scale.

[0050] 4 shows a detailed longitudinal cross-section of the membrane portion of the plates 22 of FIG. 3; however, only the portion corresponding to the paths of ten potential beamlets (only five of which are selected as final beamlets) among the many beamlets of the PD field pf is shown. As mentioned above, the illustrated embodiment implements a three-plate structure consisting of three plates 201, 202, and 203. Of these plates, the first plate 201 implements an aperture array device (AAD), the second plate 202 implements an aperture array device (beam selection plate), and the third plate 203 serves as a deflection array device (blanking plate). The first plate is an aperture array device implemented as the aperture plate 201 having multiple sets of apertures 211, 212 of different sizes and / or shapes, as further described below. Aperture 211 defines potential beamlets b1...b5, while aperture 212 defines potential beamlets b1'...b5'; all potential beamlets so formed travel towards beam selection plate 202. The beam selection plate is provided with apertures 220 such that only one set of potential beamlets, in this case beamlets b1...b5 that pass through aperture 211, are allowed to travel further, while other potential beamlets (in this case b1'...b5') are removed by being substantially absorbed in the beam selection plate. For this purpose, holes 220 in the beam selection plate have a width greater than apertures 211, 212.

[0051] Figure 5 shows a plan view of a portion of aperture plate 201. The portion shown includes only 3x3 groups of apertures, each group including three different types of apertures 211, 212, 213. Line 4-4 (in Figure 5) indicates the cutting line for the cross-sectional view of Figure 4. Arrow d12 indicates the relative offset between one type of aperture 211 and the other type of aperture 212, by which the aperture plate is shifted to select aperture 212 rather than aperture 211.

[0052] The third plate 203 of the PD system 102 is a deflection array plate, commonly referred to as a blanking plate, which has a set of holes 230 corresponding to the paths of the beamlets b1...b5 whose positions are determined by the aperture plate 201; however, the holes 230 have a width that is larger than that of the apertures 211, 212 (in other words, the holes 230 are larger) so that the beamlets can pass through the holes 230 without affecting the material of the blanking plate. Each aperture 230 is provided with electrodes 231, 232, which can impart a small but sufficient deflection (deflection) to the corresponding beamlet depending on the voltage selectively applied between each pair of electrodes 231, 232; for example, one electrode 232 is maintained at ground potential and functions as a counter electrode, while the other electrode 231 functions as an active electrode connected to a circuit layer of the blanking plate 203 for applying a potential (voltage) to deflect selected beamlet(s) b1...b5. Each beamlet can be deflected individually in this manner. The blanking plate also includes circuitry for electronic control and electrode power supply. Further details of the PD device, including details of the blanking plate circuitry, are discussed in commonly assigned / applicant U.S. Patent Nos. 6,768,125, 7,781,748, and 8,222,621 B2.

[0053] Each selected beamlet b1...b5 traverses the next hole in the plates 22 along its nominal path when the corresponding blanking electrode 231, 232 is not energized; this corresponds to the "switched-on" state of the aperture. A "switched-off" aperture is realized by energizing the electrode, i.e., by applying a transverse voltage. In this state, as shown by beamlet b2, the corresponding blanking electrode 231, 232 deflects beamlet b2 from its nominal path, thus deflecting it onto a (slightly but sufficiently) different path that ultimately reaches some absorbing surface, preferably a block aperture 17 located around one of the two crossovers c1, c2 (FIG. 1). In the exemplary illustration of FIG. 4, the deflection angle of deflected beamlet b2 is exaggerated for better visibility.

[0054] Aperture Plates and Multiple Aperture Grids

[0055] The apertures 211, 212, and preferably also the corresponding holes 220 in the beam selection plate and the corresponding holes 230 in the blanking plate, are systematically arranged along defined grids. Each grid is, for example, a regular rectangular array or a regular array forming zigzag lines extending parallel to a direction corresponding to the relative movement of the aperture images across the target, as described in U.S. Pat. No. 6,768,125. In each line of the arrangement, the offset between successive apertures of the same type is preferably a multiple of the grid width (the width between adjacent grid lines that make up one grid) underlying the aperture arrangement, as shown in FIG. 5 for one embodiment of the present invention. The holes shown in FIG. 5 represent three interlaced grids, each representative of such an arrangement. Typically, the apertures will be positioned at the points (intersections) of a substantially regular two-dimensional grid, but the grid may additionally have small deviations from a precise regular grid to account for possible distortions in the imaging system, so that small deviations in the positions of the apertures compensate for such imaging errors and achieve a compensated, precise position of each aperture image on the target.

[0056] As mentioned above, the aperture plate includes multiple sets of apertures, each of which can be selected to be imaged onto a target. Further details of the PD apparatus regarding the selection of a particular set of apertures and the alignment of the aperture plate, beam selection plate, and blanking plate with respect to one another are discussed in U.S. Patent No. 6,768,125.

[0057] FIG. 6 illustrates the problems in using a PD device as recognized by the inventors and as previously described (in the "Background Art" and "Problem to be Solved by the Invention" sections). FIG. 6 is an enlarged view of a portion of FIG. 4. Beamlet b6' (which could be any one of beamlets b1'...b5' in FIG. 4) will interact with the bulk material of the beam selection plate 202 and generate secondary particles 221, e.g., electrons. Some of the secondary particles will remain within the material, while others will be ejected from the material. Primarily intuitively, secondary particles (especially electrons) can accumulate in the vicinity of the beam selection plate and aperture plate, causing charge buildup, as indicated by reference numerals 222 and 213 in FIG. 6. When such charges accumulate, they will form an electric field, symbolically shown in Figure 6 by dashed electric field lines 223, which may have the effect of deflecting (diverting) beamlet b6 (which may be any one of beamlets b1...b5 in Figure 4), thus causing undesired beamlet misalignment at the target surface and therefore reducing pattern fidelity.

[0058] Beam selection plate with absorber structure

[0059] 7-9 illustrate an embodiment of an exemplary PD device, including an exemplary absorber array device according to the present invention. In this embodiment, the PD device 7 includes an aperture plate 701, a beamlet selection plate 702, and a blanking plate 703. (The aperture plate 701 and blanking plate 703 can be configured (embodied) in the same layout as the corresponding components 201 and 203 described above.) More specifically, FIG. 7 shows a vertical cross section similar to FIG. 4, FIG. 8 shows a detail of a portion of FIG. 7 for one group of potential beamlets and selected beamlets, and FIG. 9 shows a plan view of the beamlet selection plate 702; line 8-8 (in FIG. 9) indicates the cutting line for the cross section shown in FIG. 7. The beamlet selection plate 702 constitutes (embodies) an absorber array device according to the present invention; it includes a plurality of holes 70 corresponding to the apertures 71 of one of the sets of apertures in the aperture plate 701. Furthermore, the beamlet selection plate 702 is provided with charged particle absorbing structures 724 configured to absorb potential beamlets b1'...b5' of the other set(s) of apertures 72 before they can impinge on the blanking plate 703. The charged particle absorbing structures 724 are preferably configured (embodied) within the bulk material (part) of the beamlet selection plate 702.

[0060] Typically, a charged particle absorber structure includes multiple absorber regions surrounded by raised regions facing the absorber regions and forming walls called absorber flanks; these walls can be formed vertically or nearly vertically at an angle approaching 90°, as can be achieved by known processing methods. In many embodiments, as shown in Figures 7 and 8, for example, structure 724 can be configured (embodied) as multiple absorbers formed as blind holes or trenches. Such blind holes and / or trenches can be formed, for example, using known types of reactive etching methods. Here, the term "blind hole" refers to a recess-like structure having limited dimensions in the X and Y directions and corresponding to the area where one beamlet impinges. The term "trench" refers to a wider structure that encompasses the impingement area of ​​more than one beamlet, such as from two, three, or four beamlets to a substantial number of beamlets, or even an entire row of beamlets. Implementing the charged particle absorption structure as a plurality of blind holes (or depressions) is preferred, as this structure ensures that the charge accumulated by the beamlets and any secondary particles are enclosed and confined on all sides.

[0061] The blind holes or trenches are preferably configured (implemented) to have a lateral width greater than the size of the beamlet-defining apertures (s) formed within the aperture plate 701 (see apertures 211, 212 in FIG. 5 ) and a margin that can be determined to cover possible tolerances and deviations, so as to allow the entire amount of beamlets b1′...b5′ to be absorbed in the structure 724. The additional margin in the lateral width of the blind holes also serves to allow for a certain amount of lateral misalignment between the aperture plate 701 and the beamlet selection plate 702. Simulations calculated by the applicant have shown that the blind holes or trenches can advantageously be configured (implemented) to have a depth-to-width ratio greater than 2, although other aspect ratios of 1.5 or greater or 3 or greater are also expected to be advantageous. This ensures that, referring to Figure 8, radiation-induced accumulation of charged contaminants 726 and secondary particles 727 that may be generated by beamlet b7' are positioned at the bottom surface of structure 724, which acts as an absorption region to completely or at least largely (significantly) confine the secondary particles 727 and any associated electric fields within structure 724.

[0062] As mentioned above, the angular distribution of secondary particles can essentially be described by the cosine law. If secondary particles are generated at the bottom of a blind hole, this will cause a certain amount of secondary particles to collide with the sidewalls of the blind hole. Another portion of the secondary particles will still escape through the opening at the top of the blind hole. For blind holes with a depth-to-width ratio close to 2, more than 50% of the secondary particles will be trapped inside the blind hole. A larger aspect ratio will correspondingly increase the proportion of trapped secondary particles. Therefore, possible charge accumulation at other locations (such as location 213 in FIG. 6 ) and deflection of beamlet b7 due to the electric field 728 arising from contaminants 726 caused by absorbed beamlet b7′ will be effectively reduced.

[0063] Furthermore, it may be advantageous to apply a conductive coating 725 to the surface of plate 702, this thin film being provided on both sides of the plate or at least on the upstream side. This will ensure dissipation of any accumulated charge and further reduce residual electric fields. Such a conductive coating may be realized, for example, by sputter coating the beamlet selection plate with a few nm, e.g., 10 nm, of an intrinsically highly conductive metal such as Au or Pt.

[0064] Furthermore, the PD device 7 of Fig. 7 may comprise a positioning arrangement (not shown in Fig. 7), including a positioning device such as the one shown in Fig. 2 and Fig. 3. The positioning arrangement serves to adjust the relative position in the XY plane between the aperture plate 701 on the one hand and the beamlet selection plate 702 (and blanking plate 703) on the other hand. In some embodiments, the relative position may be adjusted by an external device or manually, in which case the positioning arrangement may be omitted from the components of the PD device according to the invention.

[0065] The distance between the aperture plate 701 and the beamlet selection plate 702 is suitably chosen to allow free relative movement between these plates, with typical values ​​for this distance (i.e. the resulting free space between corresponding plates along the Z direction) being in the order of 0.5 mm to a maximum of approximately 20 mm, or preferably approximately 5 mm, and more preferably the distance may be 1-2 mm.

[0066] According to another embodiment of the present invention, shown in Figures 10 and 11, the PD device 9 may include a beamlet selection plate 902 in which charged particle absorption structures 929 are implemented as a plurality of protruding features formed in a bulk material of the beamlet selection plate 902. (The aperture plate 901 and blanking plate 903 in this embodiment may be the same as the corresponding components 701, 703 and 201, 203 (in Figure 4) in the embodiment of Figure 7.) For example, the absorption structures 924 may be implemented as free-standing prismatic objects 929, hereinafter referred to as "shield electrodes" or "screening electrodes", made of, for example, a conductive metal material or coated with a conductive thin film at least on their surfaces. The shielding electrodes may be arranged in such a manner as to form an arrangement substantially corresponding to an "absorber tube" having a rectangular cross-sectional shape. Galvanic deposition techniques, as are well known in the art, can also be used to fabricate shielding electrodes on the surface of the beamlet selection plate. Figure 10 shows a longitudinal cross section similar to Figures 4 and 7, and Figure 11 shows a top view of beamlet selection plate 902; line AA (in Figure 11) indicates the cut line of the cross section shown in Figure 10.

[0067] The opposing walls of the shielding electrodes 929 constitute (embodiment) absorber flanks that surround the area of ​​the absorbing region 923 in this embodiment. The lateral distance w9 between the opposing walls of these shielding electrodes, measured across the position of the beamlets to be absorbed, can preferably be larger than the size of the beamlet-defining apertures (see apertures 211, 212 in FIG. 5 ) formed within the aperture plate 901, or possibly a margin that can be determined to cover possible tolerances and deviations in this size, so that the entire amount of unselected beamlets b1′...b5′ can be extinguished (absorbed) in the surface portion between the shielding electrodes (thus serving as an absorbing region). A slightly larger lateral distance w9 between the shielding electrodes can additionally account for a certain amount of lateral misalignment between the aperture plate 901 and the beamlet selection plate 902. (Blanking plate 903 is equivalent to blanking plate 703 of the previously described embodiment.) As with structure 724, the space ("absorber tube") enclosed by shielding electrodes 929 may advantageously be configured (embodied) with a depth-to-internal width ratio greater than 2, although other aspect ratios as noted above may also be advantageous. Considerations regarding the efficiency of containment of secondary particles and shielding of the electric field generated by accumulated charge are the same as those discussed for the previous embodiments of the invention.

[0068] In one variant, the absorber structure 924 may be configured (embodied) as a plurality of tubes of prismatic or cylindrical shape, for example made of a conductive metallic material or at least its surface coated with a conductive thin film. Galvanic deposition methods, as known in the art, may also be used to fabricate the cylindrical / prismatic tubes on the surface of the beamlet selection plate. Similar to the structure 724, the cylindrical / prismatic tubes may advantageously be configured (embodied) to have a depth-to-internal width ratio greater than 2, although other aspect ratios, as mentioned above, may also be advantageous. Considerations regarding the efficiency of containment of secondary particles and shielding of the electric field generated by accumulated charges are the same as those discussed for the above embodiments of the present invention.

[0069] The inner diameter w9 of the tube (i.e., the "tube" or prismatic / cylindrical tube formed by the shielding electrodes) can preferably be equal to or slightly larger than the size of the beamlet-defining apertures (see apertures 211, 212 in FIG. 5) formed inside the aperture plate 901, or possibly plus a margin that can be determined to cover possible tolerances and deviations in this size. This will ensure that the entire amount of beamlets b1'...b5' is extinguished (absorbed) at the bottom surface of the structure that serves as the absorption region 923 inside the tube. A slightly larger inner diameter w9 of the tube can ensure that a certain amount of lateral misalignment between the aperture plate 901 and the beamlet selection plate 902 is tolerated (accounted for).

[0070] All or part of the above embodiments can be described as the following supplementary notes, but are not limited thereto. [Appendix 1] A multi-beam pattern definition device for use in a particle beam processing or inspection device. The multi-beam pattern definition device is adapted to be illuminated by a beam of charged particles and to pass the beam through a number of apertures to form a corresponding number of beamlets (number of the apertures). The multi-beam pattern definition device an aperture array device in which the plurality of apertures are formed, the aperture array device including at least two sets of apertures (aperture sets), each set including a plurality of apertures transparent to the beam, the apertures of each set being arranged in a substantially regular aperture arrangement on the aperture array device, the aperture arrangements of the sets being at least partially interlaced, the aperture arrangements constituting mutually equivalent arrangements offset with respect to each other by respective displacement vectors at least in an area where the aperture arrangements interlace (hereinafter referred to as an "aperture arrangement interlace area"); and an absorber array device positioned downstream of the aperture array device and having a plurality of holes configured to pass beamlets formed by at least a subset of the apertures; Includes: The absorber array device includes a charged particle absorption structure (body) including an absorption region surrounded by an absorber flank that is elevated relative to the absorption region and configured to absorb charged particles impinging on the absorption region, the absorption region being positioned at positions corresponding to apertures of at least one of the sets of apertures in at least an area corresponding to the aperture arrangement interlace area, and the plurality of holes of the absorber array device are arranged in a substantially regular arrangement in the area corresponding to the aperture arrangement of at least one other of the sets of apertures of the aperture array device. [Appendix 2] In the above multi-beam pattern definition device, The system further includes a deflection array device having a plurality of blanking holes arranged such that each of the beamlets passes through one of the plurality of blanking holes along a nominal path. The deflection array device includes a plurality of electrostatic deflection electrodes, each associated with one blanking hole and configured to deflect the beamlet passing through the respective blanking hole by an amount sufficient to deviate the beamlet from its nominal path when an activation voltage is applied to the electrode. [Appendix 3] In the above multi-beam pattern definition device, The charged particle absorption structure includes a plurality of charged particle absorber devices, each of which is positioned at a location on the absorber array device corresponding to a location where one of the beamlets impinges and is configured to absorb charged particles of that beamlet. [Appendix 4] In the above multi-beam pattern definition device, The charged particle absorber devices are configured as depressions or blind holes formed in the surface of the absorber array device, the depressions preferably extending along the corresponding direction of the beamlets impinging on them. [Appendix 5] In the above multi-beam pattern definition device, The depressions or blind holes have a depth to width ratio greater than two. [Appendix 6] In the above multi-beam pattern definition device, The charged particle absorber device is configured as an electrode-like structure protruding from a surface of the absorber array device. [Appendix 7] In the above multi-beam pattern definition device, The electrode-like structures have a depth-to-width ratio greater than two. [Appendix 8] In the above multi-beam pattern definition device, The charged particle absorption structure comprises a trench or hole having a width that is a multiple of two greater than the lateral size of the apertures of the aperture array device. [Appendix 9] In the above multi-beam pattern definition device, The absorber array device further includes a conductive coating formed on at least the side thereof facing the aperture array device. [Appendix 10] In the above multi-beam pattern definition device, At least one of the aperture array device and the absorber array device is movable in a plane transverse to the propagation direction of the beam to adjust the relative position of the aperture array device with respect to the absorber array device, and is configured to selectively bring any selected set of the sets of apertures of the aperture array device into alignment (registered) with the plurality of holes of the absorber array device at least in the aperture arrangement interlace region. [Appendix 11] In the above multi-beam pattern definition device, The apparatus further includes a positioning device for positioning at least one of the aperture array device and the absorber array device to adjust the relative position of the aperture array device with respect to the absorber array device. The positioning device is configured to selectively bring a selected set of the sets of apertures of the aperture array device into alignment with the plurality of holes of the absorber array device in at least the aperture arrangement interlace region. [Appendix 12] In the above multi-beam pattern definition device, The absorber array device is positioned downstream of and at a predetermined distance from the aperture array device.

[0071] Within the scope of the entire disclosure of the present invention (including the claims and drawings), modifications and adjustments of the embodiments are possible based on the basic technical concept thereof. Furthermore, within the scope of the entire disclosure of the present invention, various combinations and selections (including "non-selection") of various disclosed elements (including each element of each claim, each element of each embodiment, each element of each drawing, etc.) are possible. In other words, the present invention naturally includes various modifications and alterations that would be possible by a person skilled in the art in accordance with the entire disclosure, including the claims and drawings, and the technical concept of the present invention. In particular, with regard to the numerical ranges described herein, any numerical value or subrange included within the range should be construed as being specifically described, even if not otherwise specified.

[0072] Furthermore, the reference numerals in the drawings attached in the claims are intended solely to aid in the understanding of the invention and are not intended to limit the invention to the embodiments and examples shown.

[0073] Furthermore, the entire contents of each of the above references are incorporated herein by reference.

Claims

1. 1. A multi-beam pattern definition apparatus for use in a particle beam processing or inspection apparatus, comprising: the multi-beam pattern definition device is adapted to be illuminated by a beam of charged particles and to pass the beam through a number of apertures to form a corresponding number of beamlets; The multi-beam pattern definition device comprises: an aperture array device (701, 901) on which the plurality of apertures are formed, the aperture array device comprising at least two sets of apertures (71, 72), each set comprising a plurality of apertures transparent to the beam, the apertures of each set being arranged in a substantially regular aperture arrangement on the aperture array device, the aperture arrangements of the sets being at least partially interlaced, the aperture arrangements constituting mutually equivalent arrangements offset with respect to each other by respective displacement vectors at least in the region where the aperture arrangements interlace (hereinafter referred to as the "aperture arrangement interlace region"); an absorber array device (702, 902) positioned downstream of said aperture array device and having a plurality of holes (70, 90) configured to pass beamlets formed by at least a subset of said apertures (71); Including, the absorber array device comprises a charged particle absorber structure (724, 924) including an absorber region surrounded by an absorber flank elevated relative to the absorber region and configured to absorb charged particles impinging on the absorber region, the absorber region being positioned at a position corresponding to the apertures of at least one of the sets of apertures (72) at least in an area corresponding to the aperture arrangement interlace area, the plurality of holes (70, 90) of the absorber array device being arranged in a substantially regular arrangement in the area corresponding to the aperture arrangement of at least one other of the sets of apertures (71) of the aperture array device (701, 901), Multi-beam pattern definition device.

2. 2. The multi-beam pattern definition apparatus according to claim 1, a deflection array device having a plurality of blanking holes arranged such that each of the beamlets passes through one of the plurality of blanking holes along a nominal path; the deflection array device includes a plurality of electrostatic deflection electrodes, each electrode associated with one blanking hole and configured to deflect a beamlet passing through a respective blanking hole by an amount sufficient to deviate the beamlet from its nominal path when an activation voltage is applied to the electrode; A multi-beam pattern definition device comprising:

3. 3. The multi-beam pattern definition device according to claim 1, the charged particle absorbing structure includes a plurality of charged particle absorbing devices, each charged particle absorbing device positioned at a position on the absorber array device corresponding to a location at which one of the beamlets impinges and is configured to absorb the charged particles of that beamlet; A multi-beam pattern definition device comprising:

4. 2. The multi-beam pattern definition apparatus according to claim 1, the charged particle absorber device is configured as a depression or a blind hole formed in a surface of the absorber array device, the depression extending along a corresponding direction of the beamlets impinging on the depression; A multi-beam pattern definition device comprising:

5. 5. The multi-beam pattern definition apparatus according to claim 4, The depression or blind hole has a depth to width ratio of greater than 2. A multi-beam pattern definition device comprising:

6. 2. The multi-beam pattern definition apparatus according to claim 1, the charged particle absorber is configured as an electrode-like structure protruding from a surface of the absorber array device; A multi-beam pattern definition device comprising:

7. 7. The multi-beam pattern definition apparatus according to claim 6, said electrode-like structures having a depth-to-width ratio greater than 2; A multi-beam pattern definition device comprising:

8. 2. The multi-beam pattern definition apparatus according to claim 1, The charged particle absorbing structure includes a trench or hole having a width that is a multiple of two greater than the lateral size of the apertures of the aperture array device. A multi-beam pattern definition device comprising:

9. 2. The multi-beam pattern definition apparatus according to claim 1, The absorber array device further includes a conductive coating formed on at least a side thereof facing the aperture array device. A multi-beam pattern definition device comprising:

10. 2. The multi-beam pattern definition apparatus according to claim 1, at least one of the aperture array device and the absorber array device is movable in a plane transverse to the propagation direction of the beam to adjust a relative position of the aperture array device with respect to the absorber array device and configured to selectively bring any selected set of the sets of apertures of the aperture array device into alignment with a plurality of holes of the absorber array device at least in the aperture arrangement interlace region. A multi-beam pattern definition device comprising:

11. 11. The multi-beam pattern definition apparatus according to claim 10, a positioning device for positioning at least one of the aperture array device and the absorber array device to adjust a relative position of the aperture array device with respect to the absorber array device; the positioning device is configured to selectively bring a selected set of the sets of apertures of the aperture array device into alignment with the plurality of holes of the absorber array device at least in the aperture arrangement interlace region. A multi-beam pattern definition device comprising:

12. 2. The multi-beam pattern definition apparatus according to claim 1, the absorber array device is positioned downstream of the aperture array device at a predetermined distance from the aperture array device; A multi-beam pattern definition device comprising:

Images