Manufacturing method for a monolithic multi-aperture plate and monolithic multi-aperture plate for a multi-beam electron beam system

Abstract

A monolithic multi-aperture plate and an improved manufacturing method for a monolithic multi-aperture plate for forming a plurality of electron beams for a multi-beam electron beam system are described. The monolithic multi-aperture plate consists of a monolithically constructed element with individual functional planes, a plurality of apertures and an embedded structured metal layer for electrical connection. Apart from the plurality of apertures, the monolithic multi-aperture plate contains no cavities. The monolithic multi-aperture plate is designed for better performance and longer service life.

Description

[0001] Title

[0002] Manufacturing method for a monolithic multi-aperture plate and monolithic multiaperture plate for a multi-beam electron beam system

[0003] Field of the invention

[0004] The invention relates to a multi-aperture plate for forming a plurality of electron beams for a multi-beam electron beam system and to a novel manufacturing method for same.

[0005] Prior art

[0006] With the ongoing development of ever smaller and ever more complex microstructures such as semiconductor components, there is a need to further develop and optimize planar production techniques and inspection systems for inspecting small dimensions of the microstructures. Therefore, there is a need for inspection means which can be used with high throughput to examine the microstructures on wafers with high accuracy.

[0007] Typical silicon wafers used in the production of semiconductor components have diameters of up to 300 mm. Each wafer is divided into repeating regions ("dies"). A semiconductor apparatus comprises multiple semiconductor structures, which are produced in layers on a surface of the wafer by planar integration techniques. Semiconductor wafers typically have a plane surface on account of the production processes. The structure size of the integrated semiconductor structures in this case extends from a few pm to the critical dimensions (CD) of 5 nm, with the structure sizes becoming even smaller in the near future; in future, structure sizes or critical dimensions (CD) are expected to be less than 3 nm, for example 2 nm, or even under 1 nm. For multiple applications, the specification requirement regarding the accuracy of a measurement provided by inspection equipment is even higher, for example by a factor of two or one order of magnitude. For instance, a width of a semiconductor feature must be measured with an accuracy of better than 1 nm, for example 0.3 nm or even less, and a relative position of semiconductor structures must be determined with an overlay accuracy of better than 1 nm, for example 0.3 nm or even less.

[0008] A multi-beam electron beam system is one development in the field of charged particle systems ("charged particle microscopes", CPMs). For instance, a multi-beam electron beam system is disclosed in US 7 244949 B2 and in US 2019 / 0355544 Al. In the case of a multibeam electron beam system or MSEM, a sample is irradiated simultaneously with a plurality of individual electron beams, which are arranged in a field or raster. For instance, 4 to 10000 individual electron beams may be provided as primary radiation, with each individual electron beam being separated from an adjacent individual electron beam by a pitch of 1 to 200 micrometres. For example, a multi-beam electron beam system has approximately 100 separate individual electron beams ("beamlets"), which for instance are arranged in a hexagonal raster, with the individual electron beams being separated by a pitch of approximately 10 pm in the image field. The plurality of individual charged particle beams (primary beams) are focused on a surface of a sample to be examined by way of a common objective lens. For example, the sample may be a semiconductor wafer that is secured to a wafer holder mounted on a movable stage. When the wafer surface is illuminated by the primary individual charged particle beams, interaction products, for example secondary electrons or backscattered electrons, emanate from the surface of the wafer. Their start points correspond to those locations on the sample on which the plurality of primary individual particle beams are focused in each case. The amount and the energy of the interaction products depends inter alia on the material composition and the topography of the wafer surface. The interaction products form multiple secondary individual particle beams (secondary beams), which are collected by the common objective lens and imaged on a detector, which is arranged in a detection plane, by a projection imaging system of the multi-beam electron beam system. The detector comprises multiple detection regions, each of which comprises multiple detection pixels, and the detector captures an intensity distribution for each of the secondary individual particle beams. An image field with a diameter of e.g. 100 pm is obtained in the process.

[0009] The state-of-the-art multi-beam electron beam system comprises a sequence of electrostatic and magnetic elements. At least some of the electrostatic and magnetic elements can be set in order to adapt the focus position and the stigmation of the plurality of individual charged particle beams. The state-of-the-art multi-beam system with charged particles moreover comprises at least one crossover plane of the primary or the secondary individual charged particle beams. Moreover, the state-of-the-art system comprises detection systems in order to facilitate setting. The state-of-the-art multi-beam electron beam system comprises at least one beam deflector ("deflection scanner") for collective scanning of a region of the sample surface by means of the plurality of individual primary particle beams in order to obtain an image field of the sample surface.

[0010] In a state-of-the-art multi-beam electron beam system, the plurality of individual beams are generated using a first multi-aperture plate or filter plate with a plurality of first apertures in a first raster arrangement. The plurality of individual beams subsequently pass through further multi-aperture plates, for example a second multi-aperture plate with second apertures, for example with an array of active electrostatic elements. In typical examples, there are further multi-aperture plates with further apertures in addition to the first and second multi-aperture plates. Examples for such an arrangement of multi-aperture plates are disclosed in US 11,238,054 BB, US 2022392734 AA and WO 23016678 Al. In this context, the adjustment of the plurality of individual multi-aperture plates requires special measures. In addition, deformation of individual multi-aperture plates and hence thin multi-aperture plates may occur during operation of a multi-beam microscope. This for example causes the effect that at least one individual beam no longer passes centrally through a second aperture of a second multi-aperture plate. The manufacture, joining and operation of individual multiaperture plates is therefore very prone to errors. An improved multi-aperture arrangement is therefore proposed in German patent application 102023126510.5, filed on 28 September 2023, wherein the improved multi-aperture arrangement is achieved by a monolithic multiaperture plate for a multi-beam electron beam system. The German patent application 102023209562.9, filed on 29 January 2024, describes a manufacturing process for an improved multi-aperture arrangement. A problem in the manufacture of a monolithic multiaperture plate lies in the many production steps, the success of which can only be verified at the very end. Another problem in the production of a monolithic multi-aperture plate lies in the high temperatures (e.g. >600°C) of individual manufacturing steps such as LPCVD and silicon epitaxy reactors, and so it is only possible to realize buried conductor tracks made of doped silicon. These have a higher resistance and cannot be tested in tactile fashion using a needle probe.

[0011] US 2020 / 0 317 504 Al and LL. Berry et al., Programmable aperture plate for maskless high- throughput nanolithography, Journal of Vacuum Science & Technology B15 (1997), pages 2382 - 2386, provide background art for the present patent application. ion of the invention

[0012] The present patent application claims the priority of German patent application No. 10 2024 105 793.9 filed on 29.02.2024, the disclosure of which in the full scope thereof is incorporated in the present patent application by reference.

[0013] One problem addressed by the invention is therefore that of specifying an improved manufacturing method for a monolithic multi-aperture plate. A further problem addressed by the invention is that of providing a further improved multi-aperture arrangement for generating or forming the plurality of electron beams for multi-beam electron beam systems, which is suitable for the increased demands in respect of resolution and accuracy when performing a wafer inspection task and which can be manufactured with great reliability.

[0014] The improved multi-aperture arrangement according to one embodiment of the invention is provided by a monolithic multi-aperture plate for a multi-beam electron beam system. The monolithic multi-aperture plate contains a plurality of apertures which form continuous connections between a first side or top side and a second side or underside of the monolithic multi-aperture plate. Apart from the apertures, the monolithic multi-aperture plate has no gaps or cavities where contamination could accumulate and make operation in vacuo more difficult. The monolithic multi-aperture plate essentially consists of a first, conductive semiconductor material, a second, insulating semiconductor material compound and embedded metallic layers. In one example, the monolithic multi-aperture plate is monolithically formed in its entirety, without separation points or cavities (apart from the plurality of apertures), from the first, conductive semiconductor material, the second, insulating semiconductor material compound and metallic layers, enclosed by an absorber layer as capping layer. Optionally, a thin layer of low conductivity may additionally still be present on the inner surfaces of the apertures. In this case, however, the monolithic multiaperture plate is constructed to an extent of more than 95% from the first, conductive material (for example doped silicon or polysilicon) and a second, insulating material compound (for example silicon dioxide). The multi-aperture plate is not stacked from individual multi-aperture plates with intervening distances, and so it is possible to manage without error-prone adjustment and connection, and there are no additional cavities where contamination may accumulate. Instead, the multi-aperture plate is formed monolithically from at least two precursors by means of integral joining (so-called bonding).

[0015] According to one embodiment, a monolithic multi-aperture plate is provided for a multibeam electron beam system having a plurality of apertures, wherein the monolithic multiaperture plate contains continuous connections between a first side or top side and a second side or underside of the multi-aperture plate. The top side refers to the first side on which an incident electron beam is incident or the first side which faces the incident electron beam. The multi-aperture plate consists of a sequence of functional layers and an embedded structured metal layer with embedded metallic connection channels. Each functional layer consists of a structured, doped and hence conductive semiconductor material and of an insulating semiconductor compound which is arranged between the structured doped semiconductor material. Structured regions of doped semiconductor material for example form active electrodes, shielding elements or conductive connection channels.

[0016] In one example, the monolithic multi-aperture plate contains at least two active functional layers. The structured metal layer is arranged between the first active functional layer and the second active functional layer and thus embedded between the layers consisting of doped semiconductor material and the insulating semiconductor compound. For example, the doped semiconductor material is doped silicon; for example, the insulating semiconductor compound consists of silicon dioxide.

[0017] In one example, an active functional layer contains a plurality of in each case at least one electrode at each of the apertures. The electrodes are formed from doped semiconductor material and are connected in each case to an external voltage supply on an individual basis via the embedded, structured metal layer.

[0018] In one example, the monolithic multi-aperture plate also comprises an absorber layer on the top side. The absorber layer on the top side faces an incident electron beam. The incident electron beam may pass through the absorber layer at the apertures and is otherwise absorbed by the absorber layer. A material of the absorber layer may be gold, aluminium or tungsten, but other metals with a high atomic number are also possible.

[0019] In one example, the faces on the inside of an aperture, comprising the faces of the electrodes, are additionally coated with a thin layer of low conductivity. This reduces the adhesion of charges during operation. The thin layers of low conductivity in the apertures are designed to be so thin, for example a few nm, that the layers have a high resistance and thus do not significantly disturb the electric potentials applied to the electrodes.

[0020] In the inner region where the apertures are arranged, the monolithic multi-aperture plate of one example has a thickness T between the first side or top side and the second side or underside of no less than 75 pm, for example more than 100 pm, and for example 200 pm or 500 pm.

[0021] In one example, the monolithic multi-aperture plate has openings at at least a top side or underside, for electrical contacting of the fully embedded metallic connection channels. For example, these openings thus extend from the top side to the embedded structured metal layer and enable electrical contacting from the outside. These openings may have diameters of more than 500 pm or greater still, for example a few mm.

[0022] In one example, the embedded structured metal layer separates a first partial substrate of the monolithic multi-aperture plate from a second partial substrate of the monolithic multiaperture plate, wherein in the edge region the first partial substrate projects beyond the second partial substrate in a lateral direction, and the projecting surface of the otherwise embedded structured metal layer contains contact points for electrical contacting of the embedded metallic connection channels.

[0023] A further embodiment provides a method for producing a monolithic multi-aperture plate. The method comprises manufacturing steps VAI for the production and structuring of a first substrate made of doped silicon and silicon dioxide and application of a first structured metal layer to the first substrate. The method further comprises manufacturing steps VA2 for the production and structuring of at least one second substrate made of doped silicon and silicon dioxide and application of a second structured metal layer to the second substrate, wherein the first and the second structured metal layer have at least partially overlapping regions. The method further comprises integral bonding of the first and the second substrate and over the first and second structured metal layers such that the first and second structured metal layers form a structured metal layer which is embedded on both sides in doped silicon and silicon dioxide and has embedded metallic connection channels. Integral bonding is implemented by process steps at temperatures significantly lower than 600°C, for example at 200°C or less. Thus, the embedded structured metal layer survives, and metal layers may be embedded in a monolithic substrate made of polysilicon.

[0024] Each of the structured metal layer interfaces of the first and second substrates form the bonding faces for integral bonding. Each interface comprises areas made of metal and areas made of silicon dioxide. In the method step, opposing areas made of metal and silicon dioxide are integrally bonded to one another. In one example, only a limited portion of less than 20%, for example less than 10%, of the surface of an interface of a structured metal layer has structures made of metal, wherein the predominant portion of for example more than 80% of the surface is formed from insulating silicon dioxide. The portions of the surface made of metal form the electrical contact faces of the two substrates or, for example, conductive connections on at least one of the two substrates. The individual structured regions made of metal are separated by the silicon dioxide regions.

[0025] In one example, the first and second structured metal layers have at least partially overlapping regions. In one example, the first and second structured metal layers have predominantly or completely overlapping regions. In one example, the structure of the second structured metal layer is formed as a mirror image to the structure of the first structured metal layer.

[0026] In one example, the method further comprises applying an absorber layer to and structuring said absorber layer on a top side, and etching the apertures.

[0027] In one example, a manufacturing step VA, VAI or VA2 contains at least one two-fold repetition of a step sequence, wherein the step sequence may contain the following individual steps:

[0028] - first lithographic structuring of a smoothed, for example polished, silicon dioxide layer,

[0029] - deposition of a doped polysilicon layer,

[0030] - optionally chemical mechanical polishing (CMP) of the doped polysilicon layer,

[0031] - second lithographic structuring of the e.g. polished doped polysilicon layer, - etching of the doped polysilicon layer for structuring purposes,

[0032] - coating of the surfaces with silicon dioxide,

[0033] - optionally chemical mechanical polishing (CMP) of the silicon dioxide surface.

[0034] Lithographic structuring for example contains at least the steps of a coating with a photoresist, a direct writing or photolithographic exposure, and a step of etching for the formation of a structure.

[0035] In a further embodiment, a multi-beam electron beam system having a monolithic multiaperture plate according to the first embodiment is provided. In one example, the multibeam electron beam system comprises a first filter plate arranged in the beam path of the electron beam between the particle source and the monolithic multi-aperture plate. This reduces the load on the monolithic multi-aperture plate. In one example, a monolithic multiaperture plate contains at least two active functional layers and, embedded between these, a structured metal layer with a plurality of metallic connection channels for individual control of individual electrodes in the active functional layers. In one example, a monolithic multi-aperture plate contains at least one active functional layer with an array of multipole elements with a plurality of electrodes at each aperture.

[0036] The improved monolithic multi-aperture plate thus enables improved individual beam shaping or deflection of a plurality of individual electron beams of a multi-beam system, for example of 91, more than 300, or even more than 1000 individual electron beams. In general, semiconductor manufacturing technologies may be used to manufacture a multiaperture plate with high precision. Furthermore, the monolithic design ensures high manufacturing precision throughout the monolithic multi-aperture plate. By using a metallic bonding face to join two substrates manufactured using MEMS technology, highly efficient metallic connections may be integrated into the improved monolithic multi-aperture plate. The metallic connections - apart from contacts with e.g. electrodes or conductive connections made of doped silicon - are completely embedded in non-conductive semiconductor compounds such as silicon dioxide. The fully embedded metallic connections are thus well protected against environmental influences, especially free electrons such as scattered electrons.

[0037] The improved monolithic multi-aperture plate allows an individual provision of for example more than 100, more than 500, or more than 1000 voltages with reduced power dissipation and high reliability. In particular, the relatively long wiring sections from the inner region of a multi-aperture plate to the periphery or the outer region may be embodied as metallic conductors. For example, it is also possible to apply relatively high voltages of more than approximately 100 V to individual electrodes and thus achieve greater effects. Furthermore, a long service life of a multi-beam system is also achieved.

[0038] The joining of at least two substrates manufactured using semiconductor technology enables an integral bond of the substrates both via mirror-image metallic bonding faces (for example copper on copper) and via the mirror-image structures made of the insulating semiconductor compound, for example silicon dioxide on silicon dioxide. The joining of at least two substrates manufactured using semiconductor technology also allows a parallelization of the production method and a significant reduction in the manufacturing steps to the end product. In particular, the structured metal surfaces that form the bonding faces of each substrate allow testing of the individual substrates before joining the substrates in order to complete the monolithic multi-aperture plate. This also reduces the number of rejects during manufacture and increases the efficiency of manufacture. By way of the production method using integral bonding technology, it is therefore also possible to embed metal layers or metallic connection channels in a monolithic multiaperture plate. The improved monolithic multi-aperture plate consists of at least two substrates, each containing an active functional layer having a plurality of electrodes for influencing electron beams on an individual basis. Thus, the influencing of electron beams may be distributed among two functional layers, depending on the requirements, or more complex influencing of an electron beam is possible. An improved monolithic multi-aperture plate may also be constructed from more than two substrates and may have more than one structured metallic connection layer.

[0039] The various embodiments and aspects of the invention may be combined wholly or partly with one another, provided that no technical contradictions arise as a result.

[0040] The invention will be understood even better with reference to the accompanying figures.

[0041] Fig. 1 shows a multi-beam system having a monolithic multi-aperture plate

[0042] Fig. 2 illustrates a component of a further embodiment of a multi-beam system

[0043] Fig. 3 shows a cross section through a monolithic multi-aperture plate

[0044] Fig. 4a-d, 5a, b show method steps during the manufacture of a monolithic multiaperture plate

[0045] Fig. 6 shows an intermediate result of further manufacturing steps for a monolithic multi-aperture plate

[0046] Fig. 7a-c show a further method step during the manufacture of a monolithic multi-aperture plate Fig. 8a-e show further method steps during the manufacture of a monolithic multi-aperture plate

[0047] Fig. 9 shows a monolithic multi-aperture plate

[0048] Fig. 10 shows a further example of a monolithic multi-aperture plate

[0049] Fig. lla-e show an example of the bonding regions of a monolithic multiaperture plate

[0050] Fig. 12a, b shows examples of an electrical connection of a monolithic multiaperture plate

[0051] Fig. 13a, b show an arrangement of electrodes in an aperture of a monolithic multi-aperture plate

[0052] Fig. 14 illustrates the method steps for the manufacture of a monolithic multi-aperture plate

[0053] Figure 1 schematically shows an example of a multi-beam electron beam system 1 according to one embodiment. The multi-beam electron beam system 1, also referred to as a multibeam system 1 below, comprises a beam generating apparatus 300 having a particle source 301 for generating charged particles, for example an electron source. A divergent particle beam 309 is collimated by a sequence of condenser lenses 303 and is incident on a monolithic multi-aperture plate 306. Optionally, a deflector or stigmator 302 is provided for adjusting the illumination beam 309. The multi-beam system 1 according to the first embodiment comprises exactly one monolithic multi-aperture plate 306. A plurality of individual particle beams 3 or individual electron beams 3 are generated and formed by the monolithic multi-aperture plate 306 (also referred to as a micro-optical unit 306). Midpoints of apertures in the monolithic micro-optical unit 306 are arranged in a raster arrangement in a first field which is imaged onto a further raster arrangement formed by beam spots 5 in an object plane 101. The distance between the midpoints of beam spots 5 in the object plane 101 can be 5 pm, 10 pm or 100 pm, for example. The pitches of the apertures in the monolithic multi-aperture plate 306 are 100 pm, for example. The diameters D of the apertures are smaller than the pitch of the midpoints of the apertures; examples of the diameters are 0.2 times, 0.4 times and 0.8 times the pitches between the midpoints of the apertures.

[0054] The monolithic micro-optical unit 306 and field lenses 307 and 308 are configured to generate a plurality of focus points 323 of primary beams 3 in a raster arrangement on an intermediate image surface 321. The surface 321 need not be a plane surface but may be a spherically curved surface instead, in order to account for a field curvature of the subsequent particle-optical system.

[0055] The multi-beam electron beam system 1 further comprises a system of electromagnetic lenses 103 and an objective lens 102, which image the beam foci 323 from the intermediate image surface 321 in the object plane 101 with reduced size. In between, the first individual particle beams 3 pass through the beam splitter 400 and a first collective beam deflector or scanner 110, by means of which the plurality of first individual particle beams 3 are deflected during operation and the image field is scanned. For example, the first individual particle beams 3 incident in the object plane 101 form a substantially regular field. The field formed by the incidence locations 5 may have a rectangular or hexagonal symmetry, for example.

[0056] The object 7 to be examined may be of any desired type, for example a semiconductor wafer, a lithography mask or a biological sample, and may comprise an arrangement of miniaturized elements or the like. The surface 25 of the object 7 is arranged in the object plane 101 of the objective lens 102. The objective lens 102 may comprise one or more electron-optical lenses. For example, it may be a magnetic objective lens and / or an electrostatic objective lens. The object 7, for example a wafer, is positioned on a displacement device or stage 500 with the surface 25 in the image plane 101. The surface 25 is preferably aligned perpendicular or with a slight tilt to an optical axis 105 of the objective lens 102, and the plurality of individual beams 3 are incident on the object in a manner substantially perpendicular to the object surface 25 and hence parallel to the optical axis 105. The object 25 on the wafer stage 500 is supplied with a voltage by way of a voltage supply 503.

[0057] The primary particles of the individual beams 3 incident on the object 7 generate interaction products, for example secondary electrons, backscattered electrons or primary particles which have experienced a reversal of movement for other reasons, and these interaction products emanate from the surface 25 of the object 7 or from the first plane 101 or object plane 101. The interaction products emanating from the surface 25 of the object 7 are shaped by the objective lens 102 to form secondary particle beams 9. In the process, the secondary beams 9 pass through the beam splitter 400 downstream of the objective lens 102 and are supplied to a projection system 200. The projection system 200 comprises an imaging system having a plurality of electrostatic or magnetic lenses 206 to 210, a contrast stop 214 and a multi-particle detector 207. Incidence locations 15 of the second individual particle beams 9 on detection regions of the multi-particle detector 207 are located with a regular pitch in a third field. Exemplary values are 10 pm, 100 pm and 200 pm. Furthermore, the projection system contains a second collective deflector or scanner 222 which is used to keep the incidence locations 15 of the second individual particle beams 9 on the multiparticle detector 207 at a constant position.

[0058] The multi-beam electron beam system 1 further comprises a computer system or a control unit 800, which in turn may have a single-part or multi-part design and which is designed both to control the individual particle-optical components of the multi-beam electron beam system 1 and to evaluate and analyse the signals obtained by the multi-detector 207 or the detection unit 207.

[0059] Figure 2 shows a further design of the beam generating apparatus 300 according to the embodiment. Disposed downstream of the electron source 301 there is a first stop 311 and a first multi-aperture plate or first filter plate 304 with a plurality of first apertures. The incident electron beam 309 is partially absorbed at the first filter plate 304. The first filter plate 304 is followed by a collimation lens or condenser lens 303 and the monolithic multiaperture plate 306. The monolithic multi-aperture plate 306 is followed by a field lens 308 and the further components of the multi-beam system 1, in respect of which reference is made to Figure 1 and the associated description. The plurality of primary beams are deflected through a deflection angle 109 into the direction of the optical axis 105 of the objective lens 102 by the beam splitter 400. The deflection angle 109 may be between 3° and 20°, preferably between 4° and 10°. However, larger or smaller deflection angles 109 are also possible.

[0060] The first filter plate 304 is sometimes also referred to as pre-aperture plate 304. It may serve to reduce the load on the monolithic micro-optical unit 306 due to the incident electron current from the electron beam 309. In addition to the order shown in Figure 2, other orders of aperture plate 311, the first filter plate 304 and the condenser lenses 303 are also possible. Further information relating to such multi-beam particle beam systems or multi-beam electron beam systems 1 and components used therein, such as, for instance, particle sources, multi-aperture plate and lenses, is contained in the international patent applications WO 2005 / 024881 A2, WO 2007 / 028595 A2, WO 2007 / 028596 Al, WO 2011 / 124352 Al and WO 2007 / 060017 A2 and the German patent applications DE 102013 016 113 Al and DE 10 2013 014976 Al, the disclosure of which is fully incorporated in the present application by reference.

[0061] More stringent demands are placed on a multi-beam system 1, especially for a wafer inspection. For example, the resolution of each partial image captured using each individual particle beam should be identical within a tight tolerance, for example better than 3.5 nm, better than 3.0 nm or even better. Further, the positions of the individual beam spots 5 should be very stable so that the relative positions of the individual partial images remain stable and need not be corrected by a complicated computational correction of many partial image offsets. These stringent demands lead firstly to increased demands on the design and stability of the micro-optical unit 306 and secondly to increased demands during the operation of the micro-optical unit 306. A multi-beam system 1 according to one embodiment of the invention is designed to meet these increased demands even during operation. To meet the more stringent demands, the micro-optical unit 306 according to the embodiment has a monolithic design.

[0062] A cross section of an exemplary monolithic micro-optical unit 306 is explained in detail in Figure 3. To simplify matters, only four apertures 85 for forming four individual beams 3.1 to 3.4 are illustrated. However, a much larger number of apertures is possible, for example 50, 100, 300 or even more, for example approximately 1000, depending on the number of individual particle beams 3 to be generated. A pitch Pl between the apertures is approximately 100 pm or more. For example, the apertures 85 can be arranged in a

[0063] Cartesian raster or in a hexagonal arrangement. Other arrangements are likewise possible. The apertures 85 extend between the first or top side 313 and the second side or underside 315 of the monolithic multi-aperture plate 306. Each aperture has a diameter of approximately 50 pm. In the central region 191 comprising the apertures 85, the monolithic multi-aperture plate 306 has a thickness T of more than 75 pm, for example more than 100 pm, for example 200 pm or 300 pm, or more, for example 500 pm. In particular, the monolithic multi-aperture plate 306 does not contain any thin membranes with a thickness of less than 50 pm as is conventional in the prior art. The deformation of a membrane is indirectly proportional to the third power of the thickness of a membrane. Thus, deformations are reduced by more than a factor 10, for example by more than a factor 25, in the monolithic multi-aperture plate 306 with the significantly greater thickness T. Further, the monolithic micro-optical unit 306 does not have a stacked construction and does not form a stack of individual elements, and hence it is insensitive to adjustment errors or weaknesses of any isolated connection surfaces for stacking.

[0064] An electron beam 309 emanates from an electron source 301 and is filtered at a first filter plate 304 (not depicted here). The monolithic multi-aperture plate 306 comprises a plurality of apertures 85 on the top side 313. This shapes the cross sections of the individual beams 3.1 to 3.4. In this case, each beam cross section of an individual beam 3.i corresponds to the aperture shape of an aperture 85 on the top side 313. In this case, the aperture shapes of the first beam-shaping apertures 85 may be designed to be individually different on the top side 313 and for example have different elliptical designs. For example, the top side 313 comprises an absorber layer 99 formed from a conductive material preferably with a high density or high atomic number (for example aluminium, gold, lead or tungsten). The absorber layer 99 of the monolithic multi-aperture plate 306 can be designed to be thick, for example up to 5 pm or more. Hence, the excess electrons of the pre-filtered individual beams 3 which do not pass through the apertures 85 are captured and absorbed. The absorber layer 99 is connected to a large capacitance, for example to earth (or 0 V reference potential). A thick absorber layer 99 is also suitable for capturing x-ray radiation. The absorber layer 99 is spaced apart and electrically separated from the underlying active functional layer 181b by a passive functional layer 175b.

[0065] The individual beams 3.i formed no later than at the absorber layer 99 pass through further functional layers of the monolithic multi-aperture plate 306. The functional layers in the monolithic multi-aperture plate 306 have a two-fold sequence of active functional layers 181a and 181b with electrodes 81.1 and 81.2 in this example. Finally, there is a further passive functional layer 175a and a support layer 177, which can likewise be provided as an integral constituent part of the monolithic multi-aperture plate 306. For example, the support layer 177 contains a mechanical flange or support frame 86. Together with the support frame 86, the monolithic multi-aperture plate 306 has a thickness of approximately 0.5 mm to 1 mm, for example.

[0066] During operation, electric fields that have an individual, beam-shaping or deflecting effect on each individual beam 3.i are generated at the embedded electrodes 81.1 and 81.2 by way of applied voltages. For example, single individual beams 3 are focused differently, deflected differently or otherwise influenced differently in terms of their beam shape. To this end, the embedded electrodes 81.1 and 81.2 are connected on an individual basis to a control unit 830 (see Figure 2).

[0067] Furthermore, the monolithic multi-aperture plate 306 contains at least one structured metal layer 51 approximately centrally between the top side 313 and the underside 315. This structured metal layer 51 contains metallic connection structures or connection channels (not depicted here), by means of which the embedded electrodes 81.1 and 81.2 are supplied with individual voltages. The metal layer 51 also contains metallic connection structures that form a connection of passive structures to the 0 V reference potential. Hence, fields of the individual electrodes 81 are effectively shielded from one another. The structured metal layer 51 therefore forms a connection of the electrodes 81 with metallic conduction channels, which have a lower resistance in comparison with conventional connection channels made of doped semiconductor materials. In a monolithic micro-optical unit manufactured according to the prior art, conductor tracks in the interior of the layer stack consist of semiconducting material, for example doped silicon. Semiconducting conductor tracks cannot be tested directly with a needle probe, as this results in high-resistance Schottky contacts. Thus, intermediate steps of the production process could not be followed by a functional test in the manufacture of the previous monolithic multi-aperture plates. By contrast, the metallic connection channels may be tested with tactile inspection equipment ("needle prober"). This allows a functional test to be performed during manufacture.

[0068] With the exception of this absorber layer 99 on the top side 313 and the embedded structured metal layer 51, the monolithic multi-aperture plate 306 is constructed from a first, conductive material (for example doped silicon or polysilicon) and a second, nonconductive material (for example silicon dioxide). Apart from the apertures 85, the monolithic multi-aperture plate 306 has no gaps or cavities.

[0069] The monolithic multi-aperture plate 306 has multiple planes or layers according to one embodiment. In one example, the layer sequence of the monolithic multi-aperture plate 306 contains a) a metallic absorber layer 99, b) a first passive functional layer 175b formed from doped silicon and silicon dioxide, c) a first active functional layer 181b having a plurality of electrodes 81.1, formed from doped silicon and silicon dioxide, d) an embedded structured metallic connection layer 51 formed from copper and silicon dioxide, e) a second active functional layer 181a having a plurality of electrodes 81.2, formed from doped silicon and silicon dioxide, f) at least one further passive functional layer 175a formed from doped silicon and silicon dioxide, g) a support layer 177 formed from doped silicon.

[0070] Further properties of the improved monolithic multi-aperture plate 306 are explained below using the manufacturing steps of the improved monolithic multi-aperture plate 306. One manufacturing method for an improved monolithic multi-aperture plate 306 is explained hereinafter with reference to Figure 14.

[0071] Figure 4 shows an example of individual intermediate steps during the manufacture of a monolithic multi-aperture plate 306. In a first step, a lowermost plate 171.9 of doped silicon is provided with an insulating silicon dioxide layer 169.9 (Figure 4a). The silicon dioxide layer is structured lithographically and by etching, and a further doped silicon layer 171.8 is epitaxially grown and structured. A further insulating silicon dioxide layer 169.8 is produced above this and in the vertical structures (Figure 4b). These steps are repeated (Figures 4c-d), and further layers 171.8 to 171.6 are formed. In each layer, structures are lithographically exposed and etched, and hence conductive structures are separated from one another by insulating structures 169.1-169.8 made of silicon dioxide. The conductive structures made of doped silicon subsequently form for example the embedded electrodes 81 and the conductive connections 75.1, 75.2. Hence, different functional layers of the monolithic multiaperture plate 306 are formed, including first functional layers 177 with a supporting function, second functional layers 175 which form passive electrodes, shielding electrodes and spacers, and third, active functional layers 181 with active electrodes 81. In a further step, a metal layer 51.1 is applied and lithographically structured. The result is depicted in Figure 5a. The metal layer 51.1 contains metallic conductor tracks which are connected by further contacts 53.1 to underlying conductive structures, for example an electrode 81. The metallic conductor tracks are embedded in a silicon dioxide layer 169.8. For example, copper may be used as the metal. Finally, the subsequent apertures 85.1a and 85.2a are etched into the silicon dioxide layer 169.8. The etching is done by conventional lithographic structuring and, for example, wet-chemical etching or plasma etching. The substrate 49.1 depicted in Figure 5b forms the first intermediate product in the manufacture of the monolithic multiaperture plate 306. The same reference signs as in Figures 4 and 5a are used in this context, and reference is made to Figures 4 and 5a for the description. A second substrate 49.2, which forms the second intermediate product in the manufacture of the monolithic multiaperture plate 306, is produced in a similar manner. The second substrate 49.2 is depicted in Figure 6. Similar reference signs as in Figures 4 and 5 are used in this context, and reference is made to Figures 4 and 5 for the description. The functional layer 171.3 of the second substrate 171.3 forms the top side 313 in the monolithic multi-aperture plate 306 and contains the apertures 85 of the subsequent top side 313 with, for example, different diameters Dl.l and DI.2 and, for example, different elliptical cross-sectional shapes. In a next production step, the first substrate 49.1 and the second substrate 49.2 are joined by integral bonding. The result is depicted in Figure 7a. The preferred type of integral bonding is referred to as bonding. Hybrid bonding connects both opposite metal faces and opposite faces of silicon dioxide. The lithographically defined metal faces of the metal layer 51.1 and of the mirrored structured metal layer 51.2 are used for a precise alignment between the two substrates 49.1 and 49.2. For example, an alignment of better than 1 pm is achieved, for example better than 0.5 pm or better than 0.25 pm. Figure 7b shows a detail of an example of one of the joining faces 57.1 of the structured metal layer 51.1 with a plurality of conductor tracks 51.11 and 51.12 and contacts 53.1 and 53.3. Figure 7c shows a detail of an example of one of the joining faces 57.2 of the structured metal layer 51.2 with a plurality of contacts 53.2 and 53.4. In this example, the integral metal-to-metal bond is made only at the contact faces 51.23, 51.24 (only two are labelled in Figure 7c). The two structured metal layers 51.1 and 51.2 therefore have at least partially overlapping mirror-image structures, by means of which the two substrates 49.1 and 49.2 are integrally bonded to one another, and hence, for example, electrical contacts or conductor tracks are formed. The illustration in Figure 7a, for example, shows two active functional layers; however, it is also possible to integrally add at least one further active functional layer via a further bonding face.

[0072] Following the bonding step, the two substrates 49.1 and 49.2 are securely and integrally bonded to one another and form a monolithic unit of the subsequent monolithic multiaperture plate 306. In the process, the faces of the insulating silicon dioxide structures are integrally bonded by interdiffusion, and so the metallic connection channels are completely embedded or enclosed in insulating silicon dioxide. For example, the bonding contains a thermal annealing, through which the materials of both joining faces 57 of the two substrates 49.1 and 49.2 connect to one another, for example by diffusion. This establishes a strong and highly conductive metal-to-metal connection between the two substrates 49.1 and 49.2. In one example, the integral bond extends over the surface portions of the bonding faces 57.1 and 57.2, which are formed by silicon dioxide 169.5, 169.6. In this example, the metallic contact faces 51.13, 51.23 and 51.14, 51.24 are brought into contact with force-fit only and form conductive metal-metal contact connections between the two substrates 49.1 and 49.2. In one example, a predominant portion of the surface of the bonding face is made up of silicon dioxide. For example, the portion of the surface of a bonding face made up by the embedded metallic structures is less than 30%, less than 25% or even less, for example less than 15%.

[0073] In a further method step, the support layer 177 of the second substrate 49.2, which now forms the top side of the subsequent multi-aperture plate 306, is then removed such that the top (passive) functional layer 171.3 is exposed (depicted in Figure 8a). The absorber layer 99 is then applied and structured lithographically and by etching 601 (see Figure 8b). The absorber layer 99 may for example be formed from gold or another metal with a high atomic number, in order to capture electrons and X-rays. Metals may be selected from the group of metals including aluminium, molybdenum, ruthenium, rhodium, palladium, silver, tungsten, rhenium, osmium, iridium, platinum, gold and lead.

[0074] In a further step, the back-side support layer is reduced in the inner region 191 by etching 605, and so only a circumferential collar 86 remains as a mechanical support region (Figure 8c). In the next step, the apertures 85 are etched through the multi-aperture plate 306, for example from the top, from the bottom or from both sides. The apertures 85 are filled with doped silicon, which is initially removed, for example by reactive ion etching (RIE) 607. The structures made of silicon dioxide act as an etching stop layer here, and so the apertures are initially limited by silicon dioxide (Figure 8d). Figure 8e shows the result of the through- etched apertures after wet chemical removal of the exposed silicon dioxide layers. Hence, a monolithic multi-aperture plate 306 having two active functional layers 181. a and 181. b with a plurality of electrodes 81.11, 81.21, 81.21, 81.22 is formed from the two almost identical substrates 49.1 and 49.2 with mirror-image metal structures at the bonding face 57 (Figure 9). A metallic connection layer 51 is embedded between the two active functional layers 181. a and 181. b and designed by way of the lithographic structuring to apply an individual voltage to each electrode 81 and to connect the further conductive doped silicon regions to 0 V reference potential. A voltage supply of the electrodes 81 with lower power dissipation is possible on account of the fully embedded metallic connection channels with lower resistance. Hence, it is also possible to apply higher voltages to electrodes 81 and hence, for example, generate a stronger lens effect with electrostatic lenses.

[0075] In one embodiment, a thin layer 67 of a material of low conductivity is still applied to the inner surfaces of the apertures 85 (Figure 10). Such a layer may be formed from semiconductor material, for example. Layers of low conductivity may for example also be formed from low-conductivity metals, such as titanium, chromium or tin. In both examples of Figures 9 and 10, the monolithic multi-aperture plate 306 consists of at least two active functional layers 181. a and 181. b having a plurality of mutually insulated electrodes 81.11, 81.21, 81.21, 81.22, and at least one conductive region 93 which is shielded from these and serves for shielding the fields. On the top side 313, the monolithic multi-aperture plate 306 has a plurality of openings for beam shaping of the plurality of individual beams, wherein the openings for example might have different diameters Dl.l, DI.2, while the further diameters D2 to D4 of the further, deeper regions of the apertures 85 are substantially the same in each aperture. The diameters D2 to D4 in each aperture may for example increase in the direction of propagation of the electron beams, and so the following applies: D4 > D3 >=

[0076] D2 > Dl.l.

[0077] Figure 11a shows a schematic illustration of another example of a bonding face 57a of a first substrate 49.1 with metal contacts 53a and adjustment or alignment structures 55a. A cross section along the line AA is shown in Figure lib. The electrodes 81a are connected via electrically conductive connection channels 75.1 made of doped silicon to metallic connection channels 51.11 and the metal contacts 53a. In this example, the metal contacts 53a are arranged in the metal layer 51a in the periphery around the apertures 85a. In this example, the structured metal layer 51a also has regions in which metallic connection channels 51.11 are covered by a thin silicon dioxide layer 169.5. Thin layers, in particular silicon dioxide layers with a thickness of up to 5 pm, for example 1 pm or 2 pm, may be applied to a metal layer. The application of thicker layers of silicon for example, with thicknesses greater than 5 pm, for example 10 pm or 30 pm, requires high temperatures of about 600°C, whereby a structured metal layer is destroyed. By way of the thin silicon dioxide layer of for example 1 pm thickness over a metallic conductor track 51.11 in the structured metal layer 51a, the portion of the surface of the bonding face which is formed by silicon dioxide 169.5 is increased.

[0078] Figure 11c shows the corresponding illustration of a bonding face 57b of a second substrate 49.2 with mirror symmetric metal contacts 53b and adjustment or alignment structures 55b. Figure lid shows a cross section along the line AA of the second substrate 49.2. In contrast to Figure lib, Figure lid shows an example with connection channels 75.2 made of doped silicon, which form a conductive connection between an electrode 81b and a metal contact 53b. Furthermore, at least one opening 97 is provided in the second substrate 49.2, and this opening allows contacting of some metal contacts 53b with wire connections. These 1 openings 97 may have diameters of 0.5 mm and more, and allow subsequent contacting of the metal contacts 53a or 53b from the outside. Figure lie shows an example of an alignment of the two substrates 49.1 and 49.2 with respect to one another. The two alignment marks 55a and 55b are overlayed and may be observed under infrared light, for example. Furthermore, the two marks 55a and 55b may be used in a conventional mask aligner for the alignment of the two substrates 49.1 and 49.2. Hence, a very precise adjustment and very precise integral bonding of the two substrates 49.1 and 49.2 is possible.

[0079] Figure 12a shows an example of an electrical and mechanical connection of a monolithic multi-aperture plate 306. In this example, the first substrate 49.1, which delimits the underside 315 and comprises the mechanical connection region 86, has a greater lateral extent than the second substrate 49.2, and so a projection 199 is formed on at least one side. Electrical contacting with electrical connecting lines 83 is established via this projection 199. The electrical connecting lines 83 are connected via metal contacts 53 of the structured metal layer 51 of the first substrate 49.1, for example to the electrodes 81. Via the mechanical connection region 86, the multi-aperture plate 306 is connected to the multibeam system 1, for example by an isostatic receptacle 197.1, 197.2 at at least three receptacle points.

[0080] Figure 12b shows a further example of an electrical connection of a monolithic multiaperture plate 306. In this example, the second substrate 49.2 on the top side of the monolithic multi-aperture plate 306 has an opening 97 in the peripheral region outside the inner region 191. Electrical contacting with electrical connecting lines 83 is established via this opening 97. The electrical connecting lines 83 are connected via metal contacts 53 of the structured metal layer 51 of the first substrate 49.1, for example to the electrodes 81. An electrode arrangement 81 may consist of a ring-shaped electrode, so as to form an Einzel lens. However, an electrode arrangement 81 may also be formed as a multi-pole electrode 81, for example with eight electrodes (81.1 to 81.8), which are surrounded by the insulating structure 91. Figure 13 shows an example of an electrode arrangement 81 with eight embedded electrodes 81.1 to 81.8 around an aperture 85. A respective exposed face 73 of the insulating structure 91 is situated between two respective separate, embedded electrodes. To prevent scattered electrons from reaching the exposed face 73, the electrodes are formed with grooves 63 and respective keys or tongues 61, 65 such that a key 61 of one electrode 81.1 protrudes into a groove of an adjacent electrode 81.2 and, together with the key 65 of the adjacent electrode 81.2, forms a labyrinthine vacuum gap 79 (see Figure 13b). Further, a thin layer 67 of low conductivity may be present on the inner sides of the electrodes 81.1 to 81.8.

[0081] Figure 14 schematically shows the iterative steps of the additive manufacturing method for a monolithic multi-aperture plate 306. First, in steps VAI or VA2, a substrate 49.1 or 49.2 is manufactured using polysilicon technology. The individual steps are shown and explained hereinabove using the examples of Figure 4. A sequence of method steps is implemented in step VAI or VA2, for example in the following order:

[0082] 1) first structuring of a polished silicon dioxide layer by lithographic methods and etching;

[0083] 2) deposition of doped polysilicon at a high temperature;

[0084] 3) chemical-mechanical polishing (CMP) of the deposited polysilicon;

[0085] 4) second photolithographic structuring;

[0086] 5) etching to structure the layer; 6) growing or filling of the etched structures with silicon dioxide;

[0087] 7) CMP polishing of the silicon dioxide surface;

[0088] 8) optionally, growing of a silicon dioxide layer, once again, in a further step.

[0089] These steps are repeated until the layer sequence of a substrate 49.1 or 49.2 is completed in V.l orV.2.

[0090] Next, in step VBl or VB2, the metal layer 51 is applied and structured, and the apertures are pre-etched (Figure 5 and the description in this regard). Contact points 53 to deeper embedded regions 81, 93 of conductive, doped silicon, such as the electrodes 81, may be formed prior to the metallic coating, for example by lithographic structuring and etching.

[0091] Metals may be selected from the group of metals including aluminium, molybdenum, ruthenium, rhodium, palladium, silver, tungsten, rhenium, osmium, iridium, platinum, gold and lead. For example, metal layers may be applied by conventional coating processes such as sputtering or vapour deposition. The structuring of the metal layers may be implemented lithographically and by etching, for example by wet-chemical etching or RIE. After structuring, the trenches between metallic connection channels 51.11, 51.12 (see also Figure 7b) may be filled with silicon dioxide. Conversely, it is also possible to form the structuring lithographically and by etching in silicon dioxide, and subsequently apply a metal layer. The latter may be removed again from protruding regions on the silicon dioxide layer by CMP, and so only metallic structures such as connection channels (51.11 and 51.12 in Figure 7b) and metallic contact points 53 (as in Figures 5 and 6) remain on the otherwise planar bonding face 57. In one example, a thin layer of silicon dioxide 169.5, 169.6 is applied and structured. For example, this is used to cover the metallic connection channels 51.11, 51.12 (see Figure lib). Finally, in step VCl or VC2, each substrate 49 or each half of the subsequent monolithic multi-aperture plate 306 is prequalified. Prequalification may be used to test whether electrical connection channels and electrodes have been executed correctly and that there are no short circuits or interruptions. Thus, even after a smaller number of production steps VA and VB, it is possible to rule out the possibility of faulty parts being further assembled or processed in further process steps.

[0092] Process steps VA, VB and VC may be implemented in parallel or sequentially for the production of at least two different substrates 49.1 and 49.2 using process steps V.l, subdivided into VAI, VB1 and VCl, and using process steps V.2, subdivided into VA2, VB2 and VC2, the process steps for example only differing in terms of the lithographic masks used for structuring the different aperture diameters DI to D4 or in terms of the electrical connection channels.

[0093] In step V3, the at least two substrates 49.1 and 49.2 are finally integrally bonded (see Fig. 7 and Fig. 11 and the description in this regard). Integral bonding may be supported wet- chemically, by a plasma or by the supply of heat. Heat may also be generated, for example, by ultrasound at the connection faces 57. Thermal annealing may be used to improve the integral bond. In step V4, the application of an absorber layer 99 and the etching of the apertures 85 are finally carried out (see Figures 8d, 8e and the description in this regard). Finally, in step V5, electrical contacting is implemented for individual control of the many electrodes (see Figure 12 and the description in this regard).

[0094] Via the embedded structured metal layer, a monolithic multi-aperture plate produced in this way allows an individual provision of for example more than 100, more than 500, or more than 1000 voltages with reduced power dissipation and high reliability. Metals such as copper have a higher conductivity than doped silicon by at least a factor of 10. This results in a lower internal resistance in the electrically conductive connections for controlling the electrodes. For example, the relatively long wiring sections from the inner region of a multiaperture plate to the periphery or the outer region, in particular, are embodied as metallic conductors. This renders it possible to apply relatively high voltages of more than approximately 100 V, for example 300 V or higher still, to individual electrodes and thus achieve greater effects.

[0095] A list of reference signs is provided:

[0096] 1 Multi-beam electron beam system

[0097] 3 Individual particle beams

[0098] 5 Beam spots

[0099] 7 Object or wafer

[0100] 9 Secondary particle beams

[0101] 15 Incidence locations of the secondary individual particle beams

[0102] 25 Surface of the object

[0103] 49 Substrates

[0104] 51 Metal layer

[0105] 53 Metal contact

[0106] 55 Bonding alignment feature

[0107] 57 Bonding contact face 61 Tongue or key

[0108] 63 Groove

[0109] 65 Tongue or key

[0110] 67 Layer of low conductivity 73 Exposed contact face

[0111] 75 Electrical connection channels

[0112] 79 Labyrinthine depression

[0113] 81 Electrode or electrodes

[0114] 83 Electrical connection contact 85 Aperture or apertures

[0115] 86 Mechanical support region

[0116] 91 Insulating structure

[0117] 93 Conductive structure

[0118] 95 Electrically conductive connection 97 Bonding connection holes

[0119] 99 Absorber layer

[0120] 101 Object plane

[0121] 102 Objective lens

[0122] 103 Electromagnetic lenses 105 Optical axis

[0123] 108 Pupil plane

[0124] 109 Deflection angle

[0125] 110 Collective beam deflector 111 Plane parallel to the image plane

[0126] 112 Stigmator

[0127] 115 Beam cross sections

[0128] 119 Beam cross section of a first individual beam

[0129] 169 Silicon dioxide layer 171 Doped silicon / polysilicon

[0130] 175 Passive functional layer

[0131] 177 Support layer

[0132] 181 Active functional layer

[0133] 183 Connection layer 191 Inner membrane zone

[0134] 193 Peripheral region

[0135] 197 Receptacle or support contact

[0136] 199 Lateral depression

[0137] 200 Projection system 206 Electrostatic or magnetic lens

[0138] 207 Multi-particle detector

[0139] 208 Electrostatic or magnetic lens

[0140] 210 Electrostatic or magnetic lens 214 Contrast stop

[0141] 222 Second collective deflector

[0142] 300 Beam generation device

[0143] 301 Particle source

[0144] 303 Condenser lenses 304 First filter plate

[0145] 306 Monolithic multi-aperture plate

[0146] 307 Field lens

[0147] 308 Field lens

[0148] 309 Particle beam 311 First stop

[0149] 313 First or top side

[0150] 315 Second side or underside

[0151] 321 Intermediate image surface

[0152] 323 Focus points 400 Beam splitter

[0153] 500 Displacement device or stage

[0154] 503 Voltage supply

[0155] 601 Silicon dioxide etching 605 Back-side etching

[0156] 607 Etching of the apertures

[0157] 800 Control unit

[0158] 830 Control unit for the primary beam

Claims

Claims1. Monolithic multi-aperture plate (306) for a multi-beam electron beam system (1) having a plurality of apertures (85) that form continuous connections between a first side or top side (313) and a second side or underside (315) of the multi-aperture plate (306), wherein the multi-aperture plate (306) is formed by a sequence of functional layers (175, 177, 181) and an embedded structured metal layer (51) with embedded metallic connection channels (51.11, 51.12), wherein each functional layer (175, 177, 181) consists of a doped semiconductor material and an insulating semiconductor compound.

2. Monolithic multi-aperture plate (306) according to Claim 1, wherein the multiaperture plate (306) contains at least two active functional layers (181a, 181b) and wherein the embedded structured metal layer (51) is arranged between the first active functional layer (181a) and the second active functional layer (181b).

3. Monolithic multi-aperture plate (306) according to Claim 1 or 2, wherein each active functional layer (181a, 181b) comprises at least one electrode (81, 81.1a, 81.1b, 81.2a, 81.2b, 81.1, 81.2, 81.3, 81.4, 81.5, 81.6, 81.7, 81.8) at each of the plurality of apertures (85), each of which is individually connected to an external voltage supply (830) via the embedded structured metal layer (51).

4. Monolithic multi-aperture plate (306) according to any of Claims 1 to 3, further comprising an absorber layer (99) on the top side (313) that faces an incident electron beam.

5. Monolithic multi-aperture plate (306) according to Claim 4, wherein a material of the absorber layer (99) is gold, aluminium or tungsten.

6. Monolithic multi-aperture plate (306) according to any of Claims 1 to 5, wherein the insulating semiconductor compound is formed by silicon dioxide.

7. Monolithic multi-aperture plate (306) according to any of Claims 1 to 6, wherein the faces of an electrode (81, 81.1a, 81.1b, 81.2a, 81.2b, 81.1, 81.2, 81.3, 81.4, 81.5, 81.6, 81.7, 81.8) on the inside of an aperture (85) are coated with a thin layer (67) of low conductivity.

8. Monolithic multi-aperture plate (306) according to any of Claims 1 to 7, wherein the monolithic multi-aperture plate (306) has a thickness T between the first side or top side (313) and the second side or underside (315) of no less than 75 pm, no less than 100 pm, and in particular no less than 200 pm.

9. Monolithic multi-aperture plate (306) according to any of Claims 1 to 8, whereinon at least a top side (313) or underside (315), the monolithic multi-aperture plate (306) has openings (97) serving for electrical contacting of the embedded metallic connection channels (51, 51.11, 51.12).

10. Monolithic multi-aperture plate (306) according to any of Claims 1 to 9, wherein the embedded structured metal layer (51) separates a first partial substrate (49.1) of the monolithic multi-aperture plate (306) from a second partial substrate (49.2) of the monolithic multi-aperture plate (306), and wherein the first partial substrate (49.1) projects beyond the second partial substrate (49.2) in a lateral direction, and the projecting surface of the otherwise embedded structured metal layer (51) of the first partial substrate (49.1) contains contact points (53.1, 53.2) for electrical contacting of the embedded metallic connection channels (51, 51.11, 51.12).

11. Method for producing a monolithic multi-aperture plate (306) having a plurality of apertures (85) that form continuous connections between a first side or top side (313) and a second side or underside (315) of the multi-aperture plate (306), comprising- manufacturing steps VAI for the production and structuring of a first substrate (49.1) made of doped silicon and silicon dioxide,- forming a first connection plane (57.1) by applying a first structured metal layer (51.1) to the first substrate (49.1), wherein individual structures of the first structured metal layer (51.1) are separated from each other by silicon dioxide structures (169.6) such that a portion of the surface of the first connection plane (57.1) is formed by silicon dioxide structures (169.5),- manufacturing steps VA2 for the production and structuring of at least one second substrate (49.2) made of doped silicon and silicon dioxide,- forming a second connection plane (57.2) by applying a second structured metal layer(51.2) to the second substrate (49.2), wherein individual structures of the second structured metal layer (51.2) are separated from each other by silicon dioxide structures (169.5) such that a portion of the surface of the second connection plane(57.2) is formed by silicon dioxide structures (169.6), and wherein the second structured metal layer (51.2) is formed at least in part as a mirror image of the first structured metal layer (51.1),- integrally bonding the first and the second substrate (49.1) and (49.2) such that the first and second structured metal layers (51.1, 51.2) form a structured metal layer (51) which is embedded in doped silicon and silicon dioxide and has embedded metallic connection channels (51.11, 51.12).

12. Method according to Claim 11, further comprising integral bonding of the silicon dioxide structures (169.5, 169.6) that are arranged in the connection planes (57.1, 57.2) and in each case between the structures of the first and second structured metal layers (51.1, 51.2).

13. Method according to Claim 11 or 12, further comprising- applying an absorber layer (99) to and structuring said absorber layer on a top side(313), and- etching through the apertures (85).

14. Method according to any of Claims 11 to 13, wherein each of the manufacturing steps VAI, VA2 contains an at least two-fold repetition of a sequence of steps, consisting of- first lithographic structuring of a polished silicon dioxide layer,- deposition of a doped polysilicon layer,- second lithographic structuring of the polished doped polysilicon layer,- etching of the polished doped polysilicon layer for structuring purposes,- coating of the surfaces with silicon dioxide.

15. Method according to Claim 14, further comprising chemical mechanical polishing (CMP) of a doped polysilicon layer.

16. Method according to Claim 14 or 15, further comprising chemical mechanical polishing (CMP) of a silicon dioxide surface.

17. Method according to any of Claims 11 to 16, wherein a portion of the surface formed by silicon dioxide structures (169.5, 169.6) in a connection plane (57.1, 57.2) is at least 70%, for example 75%, 80% or 90%.

18. Multi-beam electron beam system (1) having a monolithic multi-aperture plate (306) according to any of Claims 1 to 10.

19. Multi-beam electron beam system (1) according to Claim 18, further comprising a first filter plate (304) arranged in the beam path of the electron beam (309) between the particle source (301) and the monolithic multi-aperture plate (306).

20. Multi-beam electron beam system (1) according to Claim 18 or 19, wherein at least one active functional layer (183.1, 183.2, 183.3) of the monolithic multi-aperture plate (306) is formed as a multi-pole element having a plurality of electrodes (81.1 to81.8) at each aperture (85).

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