Multi-aperture array for manipulating a multitude of charged first particle beams, as well as a multitude particle beam system with the multi-aperture array

Abstract

A multi-aperture array for manipulating a plurality of charged first single-particle beams, comprising: a base body with a plurality of apertures, wherein, during operation of the multi-aperture array, one of the charged first single-particle beams passes through each aperture; at least a plurality of first electrodes, wherein one of the first electrodes is arranged at each of the apertures to individually influence the first single-particle beam passing through the aperture, and wherein each of the first electrodes is connected to a control unit; wherein the base body has a first depth TG in a z-direction along which the first apertures extend through the base body; wherein the first electrodes each have a depth TE in the z-direction that is less than the depth TG, i.e., TE < TG;wherein the first electrodes are each embedded in the base body such that they are exposed in an area adjacent to and forming the aperture, and are otherwise embedded directly in the base body and thus without an electrical insulating layer; and wherein the material of the base body is glass or consists of glass.

Description

Field of invention

[0001] The invention relates generally to multi-particle beam systems and in particular to multi-beam particle microscopes that operate with a multitude of charged single-particle beams. Specifically, the invention relates to a multi-aperture array for manipulating a multitude of charged first single-particle beams and to a multi-particle beam system comprising the multi-aperture array. State of the art

[0002] With the continuous development of increasingly smaller and more complex microstructures, such as semiconductor devices, there is a need for the further development and optimization of planar fabrication techniques and inspection systems for the production and inspection of these small microstructures. The development and fabrication of semiconductor devices, for example, requires verification of test wafer designs, and planar fabrication techniques necessitate process optimization for reliable, high-throughput manufacturing. Furthermore, the analysis of semiconductor wafers for reverse engineering and the customized configuration of semiconductor devices is increasingly required. Therefore, there is a need for inspection tools that can be used with high throughput to examine microstructures on wafers with high accuracy.

[0003] Typical silicon wafers used in the production of semiconductor devices have diameters of up to 300 mm. Each wafer is divided into at least 30 to 60 repeating regions ("dies") with a size of up to 800 mm. 2A semiconductor device comprises multiple semiconductor structures fabricated in layers on a wafer surface using planar integration techniques. Due to the fabrication processes, semiconductor wafers typically have a flat surface. The feature size of the integrated semiconductor structures ranges from a few micrometers to critical dimensions (CDs) of a few nanometers, with feature sizes expected to become even smaller in the near future. It is anticipated that future feature sizes, or critical dimensions (CDs), will correspond to the 3 nm, 2 nm, or even smaller technology nodes of the International Technology Roadmap for Semiconductors (ITRS). At these small feature sizes, defects of critical dimension size must be identified quickly across a very large area.For several applications, the specification requirement for the accuracy of a measurement provided by an inspection instrument is even higher, for example by a factor of two or an order of magnitude. For example, the width of a semiconductor feature must be measured with sub-1 nm accuracy, such as 0.3 nm or even less, and the relative position of semiconductor structures must be determined with a sub-1 nm superposition accuracy, such as 0.3 nm or even less.

[0004] A more recent development in the field of charged particle microscopes (CPM) is the MSEM, a multi-beam scanning electron microscope. A multi-beam scanning electron microscope is disclosed, for example, in US 7,244,949 B2 and US 2019 / 0355544 A1. In a multi-beam electron microscope, or MSEM, a sample is simultaneously irradiated with a multitude of single-electron beams arranged in a field or grid. For example, 4 to 10,000 single-electron beams can be provided as primary radiation, with each single-electron beam separated from an adjacent single-electron beam by a distance of 1 to 200 micrometers. For example, an MSEM has approximately 100 separate single-electron beams (beamlets) arranged, for example, in a hexagonal grid, with the single-electron beams separated by a distance of approximately 10 µm.A multitude of charged single-particle beams (primary beams) are focused by a common objective lens onto the surface of a sample under investigation. The sample can be, for example, a semiconductor wafer mounted on a wafer holder attached to a movable stage. During illumination of the wafer surface with the charged primary single-particle beams, interaction products, such as secondary electrons or backscattered electrons, emanate from the wafer surface. Their starting points correspond to the locations on the sample onto which the multitude of primary single-particle beams are focused. The quantity and energy of the interaction products depend on the material composition and the topography of the wafer surface.The interaction products form several secondary single-particle beams (secondary beams) that are collected by the common objective lens and directed by a projection imaging system of the multi-beam inspection system onto a detector located in a detection plane. The detector comprises several detection areas, each containing several detection pixels, and the detector records an intensity distribution for each of the secondary single-particle beams. This results in an image field of, for example, 100 µm × 100 µm.

[0005] The prior art multi-beam electron microscope comprises a series of electrostatic and magnetic elements. At least some of the electrostatic and magnetic elements are adjustable to adapt the focus position and stigmatization of the multiple charged single-particle beams. The prior art multi-beam charged particle system also includes at least one intersection plane of the primary or secondary charged single-particle beams. Furthermore, the prior art system includes detection systems to facilitate adjustment. The prior art multi-beam particle microscope includes at least one deflection scanner for collectively scanning an area of ​​the sample surface using the multiple primary single-particle beams to obtain an image field of the sample surface.

[0006] To separate the particle-optical beam path of the primary beams from the particle-optical beam path of the secondary beams, a so-called beam splitter (also called a "beam separator" or "beam divider") is used. This separation is achieved by means of special arrangements of magnetic fields and / or electrostatic fields, for example, using a Wien filter.

[0007] Multi-particle beam systems are generally divided into single-column and multi-column systems. In single-column systems, the individual particle beams pass at least partially through the same particle optics or through one or more global particle lenses. Furthermore, in a single column, the individual particle beams are relatively close to one another. Despite the partially global particle optics, even single-column systems require individual control and / or shaping of the individual particle beams to correct imaging errors such as field curvature, field astigmatism, and other aberrations. Micro-optics can be used for this individual control and / or shaping of the individual particle beams.Micro-optics is often also referred to as a multi-beam particle generator for generating and shaping a multitude of single-particle beams. The multi-beam particle generator, or micro-optics, comprises a sequence of several multi-aperture plates that can be used for active beam shaping, or at least one of which can be used for active beam shaping. For this purpose, electrodes can be provided in the aperture area, which can be controlled collectively or individually. These can be, for example, ring electrodes or multipole electrodes. According to another example, a multi-aperture plate can be monolithic, with a voltage applied to the entire plate; that is, the monolithic multi-aperture plate is then at a specific potential, so that its apertures, in conjunction with other particle-optical elements, can create a lensing effect.Other configurations of a multi-aperture plate for active beam shaping are also possible.

[0008] For optimal single-particle beam shaping / control, it is essential that the apertures through which a single-particle beam passes are precisely aligned. For example, the centers of the apertures may need to be perfectly aligned. Furthermore, the apertures in known multi-aperture plates are relatively small; for instance, aperture diameters are often less than 100 µm, sometimes only 90 µm or less. These two conditions—small aperture diameters and precise alignment of the apertures / electrodes, including control—can be met by applying MEMS techniques to fabricate micro-optics. In other words, the fabrication of micro-optics and their multi-aperture plates utilizes processes similar to those used in semiconductor manufacturing.

[0009] The applications of semiconductor devices arise, for example, from combining areas with different doping concentrations or from the influence of insulating layers. To meet these requirements, semiconductor devices are manufactured by depositing various layers sequentially onto a wafer-shaped substrate (planar technology). A semiconductor material, usually silicon, is used as the substrate, while silicon oxide, for example, serves as the insulating layer. The deposited layers can then be structured using lithographic processes. This allows for the production of integrated circuits with conductive traces, i.e., semiconductor chips, or micro-optics with multi-aperture plates or arrays for multi-particle beam systems.

[0010] Individual manipulation of charged single-particle beams passing through the apertures of a multi-aperture plate requires a large number of electrodes, which must be correctly positioned within the semiconductor material and electrically insulated from it. Furthermore, a large number of conductive traces are needed to apply voltage to the electrodes located at each aperture. The number of these traces can be very large, and several may be required per aperture. This applies, for example, to the so-called multistigmator of a micro-optic, which has a multipole electrode, such as an octupole electrode, at each aperture. In this case, eight conductive traces per aperture are required. If the number of single-particle beams in a multi-beam particle beam system is increased, more than 1000 conductive traces are quickly required for a multi-aperture array.Each of these conductor tracks must also be carefully positioned in the semiconductor material, for example silicon, and electrically insulated from the semiconductor material, which is why the production of multi-aperture arrays for multi-beam particle beam systems is very complex, requiring many process steps and a lot of experience.

[0011] US 2020 / 0317504 A1 discloses that microlenses, microdeflectors or stigmators can be manufactured on silicon chips (e.g. on semiconductor chips) using a MEMS process.

[0012] DE 10 2008 010 123 A1 discloses a multi-beam deflector array for maskless particle beam processing. A silicon-based multi-aperture arrangement is disclosed.

[0013] IL Berry et al., Programmable aperture plate for maskless high-throughput nanolithography, Journal of Vacuum Science & Technology B 15 (1997), pages 2382 - 2386, discloses a programmable aperture plate that can be manufactured using MEMS technology. Description of the invention

[0014] It is therefore an object of the present invention to provide a multi-aperture array for a multi-beam particle beam system that is simple or easier to manufacture. The multi-aperture array should nevertheless be of at least the same quality and performance as known multi-aperture arrays.

[0015] The problem is solved by the subject matter of independent claim 1. Advantageous embodiments of the invention are evident from the dependent claims.

[0016] A fundamental aspect of the present invention is the use of glass, rather than a semiconductor material, as the base material for a multi-aperture array. Glass is inherently an insulator, allowing electrodes and associated conductive traces arranged within the base material for active beam shaping to be embedded directly into the base material without the need for an electrical insulation layer. This significantly simplifies the manufacturing process of a multi-aperture array. Furthermore, the transparency of glass offers additional advantages for process control during the fabrication of a multi-aperture array.

[0017] The use of glass as a substrate for a multi-aperture array is made possible by the fact that the process steps and MEMS methods known from semiconductor manufacturing are now also applicable to glass as a substrate material. In particular, glass wafers can, in principle, be structured using the same photolithographic methods employed for semiconductor wafers. Chemical etching and fragmentation are also possible, as with semiconductor products. Therefore, in connection with glass or quartz, the terms QMEMS and QMEMS methods or QMEMS products are also used. An overview of these methods is provided in the publications by M. Tanaka, "An overview of quartz MEMS devices", 2010 IEEE International Frequency Control Symposium, Newport Beach, CA, USA, 2010, pp. 162-167, and Linden, J., Melech, N., Sakaev, I. et al., „Femtosecond laser-assisted fabrication of piezoelectrically actuated crystalline quartz-based MEMS resonators“, Microsyst Nanoeng 9, 38 (2023).

[0018] Specifically, according to a first aspect, the invention relates to a multi-aperture array for manipulating a plurality of charged first single-particle beams. These charged first single-particle beams can be, for example, electron beams, ion beams, muon beams, or other charged particle beams. The base body has a plurality of apertures, and during operation of the multi-aperture array, each charged first single-particle beam passes through its assigned aperture. The number of apertures is matched to the number of charged first single-particle beams. The term "array" indicates that the plurality of apertures are arranged relative to one another in a fixed grid. The apertures can, for example, be arranged in a rectangular or hexagonal grid.Preferably the apertures are arranged in a hexagonal grid and the total number of apertures, which corresponds to the number of charged first single-particle beams, is 3 n (n - 1) + 1, where n is a natural number.

[0019] Furthermore, the multi-aperture array features at least a plurality of first electrodes. Each first electrode is positioned at one of the apertures to individually influence the first single-particle beam passing through that aperture. Additionally, each first electrode (and any second and / or subsequent electrodes) is connected to a control unit. The individual manipulation of a charged first single-particle beam includes, for example, focusing, deflection, or stigmatization.

[0020] The base body of the multi-aperture array has a first depth TG in a z-direction, along which the first apertures extend through the base body. The first electrodes each have a depth TE in the z-direction that is less than the depth TG, i.e., TE < TG. The first electrodes are embedded in the base body of the multi-aperture array such that they are exposed in a region adjacent to and forming the aperture, and are otherwise embedded directly in the base body without an electrical insulating layer. The base body material is either glass or consists of glass. In any case, the base body material is an insulator. Therefore, the insulating layers required for electrodes and their associated conductor tracks according to the prior art can be omitted in the multi-aperture array according to the invention.This significantly simplifies the fabrication of the multi-aperture array. This applies both to multi-aperture arrays with exactly one plurality of first electrodes per aperture, but even more so to multi-aperture arrays with a plurality of further electrodes, for example, a plurality of second electrodes, a plurality of third electrodes, a plurality of fourth electrodes, and so on. Furthermore, the transparency of glass offers additional possibilities for process control during the fabrication of a multi-aperture array.

[0021] Since the glass substrate is already self-insulating, higher voltages can be applied to the electrodes within the apertures than is possible with substrates made of a semiconductor material such as silicon, according to the prior art. This expands the application range of the multi-aperture array in a multi-beam particle beam system.

[0022] According to a preferred embodiment of the invention, each of the first electrodes is connected to an associated first conductor track within the base body. Furthermore, the first conductor tracks are each directly embedded in the glass body and, in particular, completely embedded in the glass body. Therefore, it is not necessary to surround the conductor track with an electrical insulating layer. This, in turn, simplifies the manufacturing process for the multi-aperture array.

[0023] According to a preferred embodiment of the invention, each of the first conductor tracks in the base body is angled and extends on one side in the z-direction and on the other side in a direction orthogonal to the z-direction. The direction orthogonal to the z-direction can, for example, be an x-direction or y-direction, or another direction in the x-y plane. This angled arrangement of the first conductor tracks is very easy to implement in manufacturing. The first conductor tracks again run directly within the glass body and are embedded therein. Complete embedding is again preferred.

[0024] According to a further preferred embodiment of the invention, the base body of the multi-aperture array has a top surface that, during operation of the multi-aperture array, is oriented in the direction of entry of the charged first single-particle beams. This top surface of the base body has an upper dissipation layer made of a highly conductive material, thus preventing the base body from becoming charged during operation of the multi-aperture array. The use of such dissipation layers is already known in principle. Examples of suitable materials include gold, copper, platinum, or titanium nitride.

[0025] According to a further preferred embodiment of the invention, a short-circuit protection layer is provided on the base body within each aperture. This layer extends from the top surface of the base body with the upper discharge layer to the first electrode and comprises or consists of a material with low conductivity, thus preventing a short circuit between the discharge layer and the electrode during operation of the multi-aperture array. A suitable material for the short-circuit protection layer is, for example, a metal with high sheet resistance such as tungsten or a very lightly doped semiconductor material, such as silicon.

[0026] According to a further preferred embodiment of the invention, the base body has a bottom surface which, during operation of the multi-aperture array, is oriented in the exit direction of the charged first single-particle beams from the multi-aperture array. This bottom surface of the base body has a lower conductivity layer made of a highly conductive material, thus preventing the base body from becoming charged during operation of the multi-aperture array. In practice, this charging usually occurs through scattered electrons generated during scattering processes or secondary processes in the generation of X-rays. Therefore, it is advantageous to also provide the bottom surface of the base body with a lower conductivity layer. The material can be the same as that used for the upper conductivity layer.

[0027] According to a preferred embodiment of the invention, a short-circuit protection layer is provided on the base body within each aperture. This layer extends from the underside of the base body, including the lower dissipation layer, to the first electrode and comprises or consists of a material with low conductivity, thus preventing a short circuit between the dissipation layer and the electrode during operation of the multi-aperture array. Suitable materials for the short-circuit protection layer include, for example, a metal with high surface resistance such as tungsten or a very lightly doped semiconductor material, such as silicon. When using a glass base body, the application of a short-circuit protection layer is advantageously simple compared to the application of insulating layers to conductor tracks and electrodes according to the prior art.Furthermore, the short-circuit protection layer is a layer that is directly accessible from the outside or within the apertures; it is not geometrically complex within the base body.

[0028] According to a preferred embodiment of the invention, the base body is formed in one piece. The base body then comprises several apertures, preferably all apertures, each with at least the first electrode. In particular, the base body is monolithic.

[0029] According to an alternative embodiment of the invention, the base body is formed in multiple parts. The base body, or rather the material of the base body, need not be completely contiguous in the mathematical sense. It is possible for each part of a multi-part base body to have exactly one aperture with at least the first electrode. However, it is also possible for each part of the base body to have several apertures with their associated first electrodes. This allows for a certain degree of flexibility in the manufacturing process of the multi-aperture array with a base body that contains or consists of glass.

[0030] According to a preferred embodiment of the invention, the first electrodes are designed as ring electrodes. In this case, a ring electrode is arranged at each of the apertures. Only one first conductor track associated with each ring electrode is then required, which is connected to the ring electrode within the base body.

[0031] The present invention is particularly advantageous when not just one electrode (i.e., a first electrode) is provided at each aperture, but rather several electrodes are provided at each aperture. This is the case, for example, when multipole electrodes are used. According to a preferred embodiment of the invention, the multi-aperture array further comprises a plurality of second and / or additional electrodes, with each of the second and / or additional electrodes being arranged at one of the apertures in order to individually influence the first single-particle beam that passes through the aperture during operation of the multi-aperture array. Each of the second and / or additional electrodes is connected to a control unit.The second and / or subsequent electrodes each have a depth TE2, TEi in the z-direction that is less than the depth TG of the base body in the z-direction; thus, TE2 < TG and TEi < TG, respectively. Furthermore, the second and / or subsequent electrodes are embedded in the base body such that they are exposed in a region adjacent to and forming the aperture, and are otherwise embedded directly in the base body without an electrical insulating layer. Therefore, the same principles apply to the second and / or subsequent electrodes as were already described above regarding the multiple first electrodes.

[0032] According to a preferred embodiment of the invention, a deflection unit is provided in each of the apertures by means of the electrodes surrounding them.

[0033] According to a preferred embodiment of the invention, a stigmatization unit is provided in each of the apertures by means of the surrounding electrodes. For example, it is possible to provide a quadrupole electrode or an octupole electrode with a total of eight electrodes at or in each aperture. The greater the number of electrodes per aperture, the more significant the advantages of the multi-aperture array according to the invention with a glass-based substrate become.

[0034] The base body itself comprises or consists of glass. According to a preferred embodiment of the invention, the base body can comprise or consist of one of the following materials: silicate glass, borate glass, or borosilicate glass. The foregoing terms are defined as is customary in materials science. According to a preferred embodiment of the invention, the base body consists of the material Borofloat®. Borofloat® possesses outstanding technical properties, including exceptionally high transparency, thermal resistance, and chemical resistance. It is ideal for use in the high-tech sector.

[0035] According to a preferred embodiment of the invention, the multi-aperture array comprises a support element. The base body is arranged on and connected to the support element. For example, the base body can be glued to the support element or otherwise connected to it, provided that the electrical connection is ensured.

[0036] According to a preferred embodiment of the invention, the material of the support element comprises or consists of silicon. Alternatively, the material of the support element can comprise another semiconductor material.

[0037] According to a further preferred embodiment of the invention, the material of the support element comprises or consists of glass. The material of the support element can be the same as the material of the base body, but this is not necessarily the case.

[0038] According to a preferred embodiment of the invention, the support element comprises a plurality of conductor tracks that are arranged entirely within the support element. The conductor tracks can be directly embedded in the support element if the support element is made of an insulating material such as glass. Otherwise, for example, if silicon is used as the support material, the conductor tracks must be surrounded by an insulating layer if embedded in the support element.

[0039] According to a preferred embodiment of the invention, the base body and the support element together form a combination unit. In a connection area between the base body and the support element, at least one contact pad is arranged per aperture. Each contact pad connects one of the conductor tracks within the base body to one of the conductor tracks within the support element. Each contact pad is completely located within the combination unit and is embedded directly or indirectly within the combination unit. In this embodiment of the invention, the externally routed bonding wire between a conductor track in the silicon base body and the contact pad on the silicon support body, as required by the prior art, can be avoided. In this context, the connection steps originally required with bonding wire, i.e., the external contacting of conductor tracks in the base body, are also eliminated.

[0040] According to a preferred embodiment of the invention, the support element has a top surface which, during operation of the multi-aperture array, is oriented in the direction of entry of the charged first single-particle beams. The top surface of the support element has a dissipation layer made of a highly conductive material, so that charging of the support element is prevented during operation of the multi-aperture array.

[0041] According to a further preferred embodiment of the invention, the support element has a bottom surface which, during operation of the multi-aperture array, is oriented in the exit direction of the charged first single-particle beams from the multi-aperture array. The bottom surface of the support element has a conductive layer made of a highly conductive material, so that charging of the support element is prevented during operation of the multi-aperture array.

[0042] According to a preferred embodiment of the invention, the support element is recessed from the base body in the area of ​​the apertures. The continuation of the "aperture" in the support element is therefore wider than the actual aperture. This recession of the support element prevents interference from the support element.

[0043] The embodiments described above according to the first aspect of the invention can be combined wholly or partially, provided that this does not result in any technical contradictions.

[0044] According to a second aspect of the invention, it relates to a plurality of particle beam system with at least one multi-aperture array as described above in several embodiments. It is possible to align several multi-aperture arrays with one another and to successively arrange them such that the charged first single-particle beams successively penetrate the multiple multi-aperture arrays and manipulate the single-particle beams through the multi-aperture arrays.

[0045] According to a preferred embodiment of the invention, the multi-particle beam system is a multi-beam particle microscope.

[0046] According to an alternative embodiment of the invention, the multiple particle beam system is a lithography system.

[0047] Of course, the multi-particle beam system can also be configured differently.

[0048] The invention will be better understood with the help of the attached figures. These show: Fig. 1: schematically shows a multi-beam particle beam system; Fig. 2: schematically shows the structure of a micro-optics; Fig. Figure 3: schematically shows a top view of a multi-aperture array; Fig. Figure 4: schematically shows a section of a multi-aperture array in a sectional view, where the base body consists of a semiconductor material; Fig. Figure 5: schematically shows a section of a multi-aperture array in a sectional view, where the base body consists of a glass; Fig. 6: schematically shows a ring electrode and a quadrupole electrode in a top view; Fig. 7: schematically shows an octupole electrode in a top view; and Fig. Figure 8: schematically shows a section through a multi-aperture array with a base body made of glass.

[0049] Fig. Figure 1 schematically shows a multi-beam particle beam system 1 in the form of a multi-beam particle microscope 1. The multi-beam particle microscope 1 has a beam generation device 300 with a particle source, for example, an electron source. Charged particles or electrons are generated by the beam generation device 300, for example, by thermal field emission. The emitted charged particles form a diverging particle beam 309, which is collimated by a sequence of condenser lenses 303.1 and 303.2 and strikes a multi-beam particle generator 305 with a multi-aperture arrangement. The multi-beam particle generator 305 comprises several multi-aperture plates 304, 306 and a field lens 307. A multitude of single-particle beams 3 or 3 are emitted by the multi-beam particle generator 305.Single-electron beams 3 are generated, arranged in a field which is mapped onto another field formed by beam spots 5 in the object plane 101. The distance between the centers of apertures of a multi-aperture plate 306 can be, for example, 5 µm, 100 µm, and 200 µm. The diameters D of the apertures are smaller than the distance between the centers of the apertures; examples of the diameters are 0.2 times, 0.4 times, and 0.8 times the distances between the centers of the apertures.

[0050] The multi-aperture arrangement 305 and the field lens 308 are configured to generate a multitude of focal points 323 of primary beams 3 in a grid arrangement on a surface 321. The surface 321 need not be a flat surface, but can be a spherically curved surface to accommodate field curvature of the subsequent particle optical system.

[0051] The multi-beam particle microscope 1 further comprises a system of electrostatic and magnetic field lenses 103 and an objective lens 102, which reduce the size of the beam foci 323 from the intermediate image surface 321 onto the object plane 101. The first individual particle beams 3 pass through the beam splitter 400 and a collective beam deflection system 500, which deflects the multitude of the first individual particle beams 3 during operation and scans the image field. The first individual particle beams 3 incident on the object plane 101 form, for example, a substantially regular field, with distances between adjacent point locations 5 being, for example, 1 µm, 10 µm, or 40 µm. The field formed by the point locations 5 can, for example, have a rectangular or hexagonal symmetry.

[0052] The object 7 to be examined can be of any type, for example a semiconductor wafer or a biological sample, and it can comprise an array of miniaturized elements or the like. The surface 15 of the object 7 is located in the object plane 101 of the objective lens 102. The objective lens 102 can comprise one or more electron-optical lenses. It can be, for example, a magnetic objective lens and / or an electrostatic objective lens.

[0053] The primary particles 3 striking object 7 generate interaction products such as secondary electrons, backscattered electrons, or primary particles that have undergone a reversal of motion for other reasons. These products originate from the surface of object 7 or from the first plane 101 or object plane 101. The interaction products emanating from the surface 15 of object 7 are shaped into secondary particle beams 9 by the objective lens 102. After passing through the objective lens 102, the secondary beams 9 pass through the beam splitter 400 and are directed to a projection system 200. The projection system 200 has an imaging system 205 with projection lenses 206, 208 and 210, a contrast aperture 214 and a multi-particle detector 207. The impact points 25 of the second single-particle beams 9 on the detection areas of the multi-particle detector 207 are located in a third field at a regular distance from each other.Examples of values ​​are 10 µm, 100 µm and 200 µm.

[0054] The multi-beam particle microscope 1 further comprises a computer system or a control unit or controller 10, which in turn may be designed as a single unit or as a multi-part unit, and which is designed both for controlling the individual particle-optical components of the multi-beam particle microscope 1 and for evaluating and analyzing the signals obtained with the multi-detector 207 or the detection unit.

[0055] The multi-aperture array according to the invention can be integrated into the Fig. 1 The multi-particle beam system shown can be integrated.

[0056] Further information on such multi-beam particle beam systems or multi-beam particle microscopes 1 and components used therein, such as particle sources, multi-aperture plates and lenses, can be obtained from the international patent applications WO 2005 / 024881 A2, WO 2007 / 028595 A2, WO 2007 / 028596 A1, WO 2011 / 124352 A1 and WO 2007 / 060017 A2 and the German patent applications DE 10 2013 016 113 A1 and DE 10 2013 014 976 A1, the disclosure of which is incorporated in full by reference into the present application.

[0057] The multi-aperture arrangement 305 forms a micro-optics 305, by means of which, in the example shown, during operation of the multi-particle beam system 1, the multitude of first individual particle beams 3 are initially generated at the first of the multi-aperture plates (so-called filter plate 304) and are also actively shaped at further multi-aperture plates or multi-aperture arrays. The micro-optics 305 itself can be configured differently. In particular, at least one multi-aperture array of the micro-optics can be configured according to the invention and have a base body comprising or consisting of a glass.

[0058] Fig. Figure 2 shows an example of a micro-optics 305 configured as a multi-beam generator 305. In the example shown, the multi-beam generator 305 comprises, in the z-direction, which corresponds to the propagation direction of the single-particle beams 3, a sequence of six multi-aperture plates 304, 306.1, 306.2, 306.3, 306.4, and 310, as well as an optional global lens electrode 307. Each of the multi-aperture plates 304, 306.1 to 306.4, and 310 comprises a plurality of apertures 351, each penetrated by the plurality of single-particle beams 3. The cross-section through the apertures 351 in Fig. Figure 2 is not to scale.

[0059] The multiple multi-aperture plates 304, 306.1, 306.2, 306.3, 306.4, and 310 are spaced apart from each other by spacers 93.1 to 93.5. Furthermore, a spacer 96 is provided between the final multi-aperture plate 310 and the global lens electrode 307. When a collimated particle or electron beam 309 passes through the first multi-aperture plate 304, also called a filter plate or pre-aperture plate, the multiple individual particle beams 3 are generated. The pre-aperture plate 304 comprises a metallic layer 99 on its beam-entry side for stopping and absorbing the electrons of the electron beam 309 around the multiple apertures 85. In the example shown, the material of the preparation plate 304 is made of a conductive material, e.g. doped silicon, and is at earth potential.

[0060] The next multi-aperture plate is in the example shown. Fig. 2 a multi-stigmator plate 306.1. The multi-stigmator plate 306.1 comprises a plurality of four or more electrodes 82, e.g., eight electrodes for each of the apertures. During operation of the multi-beam particle microscope 1, different voltages, for example, in the range between -20 V and +20 V, can be applied to each of these electrodes, thereby influencing each individual particle beam 3 individually. For example, it is possible to deflect each individual particle beam 3 in any direction down to a few µm using an antisymmetric voltage difference in order to pre-correct a distortion correction of the illuminating unit. An astigmatism pre-correction of each individual particle beam 3 can also be performed. With an offset voltage, each multipole element can additionally function as a single lens. The multi-stigmator plate 306.1 can comprise a multi-aperture array according to the invention, but it can also be manufactured according to the prior art on a semiconductor basis or on a silicon basis.

[0061] The multi-aperture plates 306.2, 306.3, and 306.4 can, in principle, be any path correction plates made of a conductive material, which are monolithic and to which, in the example shown, a voltage V1, V2, and V3, respectively, is applied. It is also possible for the multi-aperture plates 306.2, 306.3, and 306.4 to form a single-lens array. Different apertures 351 in the same multi-aperture plate 306.2, 306.3, and 306.4 can be identical or different, for example, having different diameters, in order to account for a field dependency of the correction when correcting the path of the individual particle beams 3.

[0062] The multi-aperture plate 310 is a two-layer multi-aperture plate comprising a plurality of ring electrodes 81 for the plurality of apertures, each ring electrode being configured to individually change or correct the focal position of the first single-particle beam 3 passing through it. The lower layer with the ring electrodes 81 can be configured as a multi-aperture array according to the invention, but it can also be conventionally silicon-based. The upper layer is insulated from the layer containing the ring electrodes 81 and is made of a conductive material such as doped silicon. Alternatively, the upper layer could be made of glass as the substrate, in which case separate insulation is unnecessary.

[0063] The field lens 307 comprises a ring electrode 94 to which a high voltage of, for example, 3 kV to 20 kV can be applied, e.g., 12 kV to 17 kV. In the example shown, the field lens 307 provides a global electrostatic lens field for global focusing of the multitude of individual particle beams 3.

[0064] Fig. Figure 3 schematically shows a top view of a section of a multi-aperture array. This could, for example, be the one in Fig. Figure 2 shows a multi-aperture array 306.1. In the example shown, the multi-aperture array 306.1 has seven apertures 85, each of which is equipped with eight electrodes, each forming a multipole electrode or octupole electrode. Each of the electrodes 82 can be individually controlled by means of the controller 10. Therefore, it is necessary that each of the electrodes 82 is connected to an individual conductor 86. Fig. Figure 3 impressively demonstrates the complexity of the arrangement of conductive tracks 86, even with only seven apertures 85. Modern multi-beam particle microscopes have significantly more apertures 85, for example, 61, 91, or even more. Multi-aperture arrays, which comprise multipole electrodes with a multitude of electrodes 82, therefore often contain around 1000 conductive tracks 86. Electrically isolating each of these conductive tracks separately is complex and time-consuming. This can be avoided by the invention. The same applies, of course, to the insulation of the electrodes 82 within the base body 360 itself.

[0065] Fig. Figure 4 schematically shows a section of a multi-aperture array 306 in a sectional view, wherein the base body 360 of the multi-aperture array 306 consists of a semiconductor material, for example silicon. The multi-aperture array 306 can, for example, be a multistigator; in Fig. Figure 4 then represents a stigmator. In this example, the electrodes 82 are not directly embedded in the base body 360, but are surrounded by an electrical insulating layer 83 within the base body 360. Only inside the aperture 351 are the electrodes 82 exposed. At the point where the conductor track 86, which contacts the electrode 82, exits the base body 360, a connecting wire 87 is arranged in the example shown. This connecting wire 87 leads to a contact pad 398, which is arranged on a support element 390. However, here too, the contact pad 398 must be insulated from the support element 390 by means of an insulating layer 397, since the support element 390 is also made of silicon and thus of a semiconductor material. A conduction layer 371 is arranged on the upper surface 370 of the base body 360 to conduct away charged particles that strike it.The same applies to the underside 380 of the base body 360, on which a conduction layer 381 is arranged. This continues in the side area and on the underside of the support element 390.

[0066] Fig. Figure 5 schematically shows a section of a multi-aperture array 350 in a sectional view, wherein the base body 360 is made of glass according to the invention. This glass can be, for example, a silicate glass, a borate glass, or a borosilicate glass. A particularly preferred material is Borofloat®.

[0067] The base body 360 made of glass is inherently an insulator, so that no separate insulating layers are required in the area of ​​the electrodes 82 and in the area of ​​the conductor tracks 86 within the base body 360.

[0068] The in Fig. The electrodes 82 shown in Figure 5 are to be understood as examples only. In principle, a multi-aperture array 350 according to the invention can have only a first plurality of first electrodes, or it can also have a second plurality of second electrodes and / or a further plurality of additional electrodes. In any case, the first electrodes 82 individually influence the respective single-particle beam 3 that passes through the aperture 351. Each of the first electrodes 82 is connected to a control unit 10 (in Figure 5). Fig. 5 not explicitly shown).

[0069] The base body 360 has a first depth TG in the z-direction, along which the first apertures 351 extend through the base body 360. The first electrodes 82 each have a depth TE in the z-direction that is less than the depth TG, i.e., TE < TG. The first electrodes 82 are each embedded in the base body 360 such that they are exposed in a region adjacent to and forming the aperture 351, and are otherwise embedded directly in the base body 360 without an electrical insulating layer. In the example shown, the base body is made of glass. Alternatively, the base body 360 can be made of glass.

[0070] In the example shown, the first electrode 82.1 and the second electrode 82.2 of the exemplary aperture 351 are each connected to an associated first conductor 86 within the base body 360. The first conductors 86 are each directly embedded in the base body, in particular, completely embedded in the base body. In the example shown, the conductors 86 are angled within the base body 360. One conductor 86 extends from electrode 82 initially in the z-direction and then, further away from the aperture 351, in a direction orthogonal to the z-direction. In the example shown, this is the y-direction.

[0071] In the example shown, the base body 360 further comprises a top surface 370, which, during operation of the multi-aperture array, is oriented in the direction of entry of the charged first single-particle beams 3. The top surface 370 of the base body 360 has an upper discharge layer 371 made of a highly conductive material. This prevents the base body 360 and the multi-aperture array 350 as a whole from becoming charged during operation. Possible materials for the upper discharge layer 371 are gold, copper, platinum, or titanium nitride.

[0072] The electrode 82 or electrodes 82 can be subjected to a higher voltage than is the case with a base body 360 made of a semiconductor material such as silicon. Conversely, it is then possible that a discharge or a short circuit may occur between the electrode 82 or electrodes 82 and the upper conduction layer 371 during operation. For this reason, in the Fig. In the embodiment shown in Figure 5, a short-circuit protection layer 372 is provided, extending from the top of the base body 360 with the upper conduction layer 371 to the electrode 82 or to the electrodes 82. The short-circuit protection layer 372 is made of or consists of a material with low conductivity. It can, for example, be a metal with high surface resistance such as tungsten or a very lightly doped semiconductor material, such as silicon.

[0073] The same applies to the underside 380 of the base body 360: The underside 380 of the base body 360 has a lower dissipation layer 381 made of a highly conductive material, so that charging of the base body 360 is prevented during operation of the multi-aperture array 350. A short-circuit protection layer 382 extends from the underside 380 of the base body 360 with the lower dissipation layer 381 to the electrode 82 or to the electrodes 82, so that a short circuit between the lower dissipation layer 381 and the electrode 82 or the electrodes 82 is prevented during operation of the multi-aperture array 350. Of course, several sections or short-circuit protection layers can be provided on the base body 360. This depends on the number of electrodes 82.Conversely, it is also possible to provide the short-circuit protection layers 372, 382 in a ring shape and to completely line the upper and / or lower area of ​​the apertures 351.

[0074] In the example shown, in Fig. 5. The base body is in turn arranged on a support element 390. The material of the support element 390 can be chosen differently. For example, the material of the support element 390 can be silicon or consist of silicon. In that case, however, the conductor tracks 391 within the support element 390 must be insulated from the support element 390 (in Fig. 5 not explicitly shown). According to an alternative embodiment of the invention, the material of the support element 390 comprises or consists of glass. The material of the support element 390 can be the same material as that of the base body, but this is not necessarily the case.

[0075] As already stated above, the electrode 82 or electrodes 82 in the area of ​​the exemplary aperture 351 of the multi-aperture array 350 can be designed differently. Fig. Figure 6 schematically shows two examples in this regard: According to Fig. 6A is a quadrupole electrode comprising a total of four individual electrodes 82.1, 82.2, 82.3 and 82.4. This shows Fig. 6A a section plane representation in the x,y-plane, if the section is along the section direction A according to Fig. 5 is carried out. In this cross-sectional view, the direct embedding of the electrodes 82.1, 82.2, 82.3 and 82.4 in the glass base body 360 is clearly visible. The direct embedding of the conductor tracks 86.1, 86.2, 86.3 and 86.4 in the glass base body 360 is also evident. The outer shape of the base body 360 in the area of ​​the aperture 351, which is shown as an example section of the entire multi-aperture array 350, is shown in Fig. The example shown in Figure 6A is square. However, it could also be designed differently. In the example shown, a conduction layer 379 is arranged on the outside or side of the base body 360 to prevent charging processes of the base body or to conduct away charged particles striking its top surface 370.

[0076] Fig. Figure 6B shows an alternative example, again only as a section of a multi-aperture array: Here, the electrode 82, which is embedded directly in the glass base body 360, is designed as a ring electrode. This is arranged circularly around the center point M and the aperture 351. The conductor track 86, which allows the electrode 82 to be individually charged, is also visible. In the example shown, the shape of the base body 360 around the aperture 351 is circular. A conduction layer 379 is again provided in the circumferential direction.

[0077] Fig. Figure 7 schematically shows another example of an arrangement of electrodes within the base body 360: In the example shown, an octupole electrode with eight individual electrodes 82.1 to 82.8 is depicted. These are arranged in a segmented fashion around the center point M of the aperture 351. Due to their direct embedding in glass, the electrodes 82.1 to 82.8 are already insulated from one another. The respective conductor tracks 86.1 to 86.8 are also directly embedded in the glass base body 360. Each conductor track 86.1 supplies exactly one electrode 82.1 with voltage. A conduction layer 379 is provided on the outer surface of the base body 360.

[0078] It is pointed out once again that the sectional view is shown by the Fig. 6A, Fig. 6B and Fig. 7 is identical in each case and the one in Fig. This corresponds to the situation shown in section 5.

[0079] Fig. Figure 8 schematically shows a section through a multi-aperture array 350 with a base body 360 made of glass. The base body 360 is arranged on a support element 390. The details of both the base body 360 and the support element 390 correspond to the details described in connection with Fig. 5 have already been described in detail. Fig.Figure 8 further facilitates understanding of the overall structure of the multi-aperture array 350. In the example shown, the base body 360 is multi-part. The base body, or rather the material of the base body 360, does not necessarily have to be completely contiguous in the mathematical sense. It is possible that each part of a multi-part base body 360 has exactly one of the apertures 351 with at least the first electrode 82. However, it is also possible that each part of the base body 360 has several apertures 351 with their corresponding first electrodes 82. This allows for a certain degree of flexibility in the manufacturing process of the multi-aperture array 350 with a base body 360 that contains or is made of glass.

[0080] Alternatively, the base body 360 can be formed in one piece. The base body 360 then comprises several apertures 351, preferably all apertures 351, each with at least the first electrode 82. In this case, the base body 360 is, for example, monolithic.

[0081] The embodiments of the invention described in the figures are not to be understood as limiting the invention, but merely serve to improve its understanding. Reference symbol list 1. Multi-beam particle system, multi-beam particle microscope 3 primary particle beams, first single-particle beams 5 beam spots, points of impact 7. Object, sample, wafer 9 secondary particle beams, second single-particle beams 10 Computer system, control 15 Sample surface, wafer surface 25 pixels of a second single-particle beam 81 Ring electrode 82 Multipole electrode 83 electrical insulation layer 84 Semiconductor layer, silicon layer 85 aperture 86 conductor track 87 Connecting wire 93 spacers 94 Ring electrode 96 spacers 99 Absorbing and conductive layer 101 Object level 102 lens 103 Field lens 105 axle 108 Beam crossing, Cross-over 200 detector system 205 Projection lens system 206 Projection lens 207 Multi-particle detector 208 Projection lens 210 Projection lens 212 Beam crossing, crossover in the projection path 214 aperture filter, contrast diaphragm 222 Collective Anti-Deflection System 300 beam generating device 301 Particle source 303 Collimation lens system 304 multi-aperture plate, multi-aperture array, filter plate, pre-aperture plate 305 Micro-optics, multi-aperture arrangement, multi-beam particle generator 306 multi-aperture plate, multi-aperture array 307 Field lens 308 Field lens 309 Particle beam 310 Multi-aperture plate 321 Intermediate image plane 323 beam foci 333 Stopping area 335 Membrane area 350 multi-aperture plate, multi-aperture array 351 Aperture 360 basic body 370 Top side of the base body 371 upper drainage layer 372 Short-circuit protection layer 379 lateral drainage layer 380 Underside of the base body 381 lower drainage layer 382 Short-circuit protection layer 389 Contact pad 390 support element 391 conductor track 392 Top side of the carrier body 393 Discharge layer 394 Underside of the carrier body 395 Discharge layer 396 Discharge layer 397 Insulation layer 398 Contact pad 400 beam switch, magnetic arrangement 500 scan deflectors 600 Moving table or positioning device TE Electrode depth in z-direction TG Depth of the base body in the z-direction M Center of an aperture x direction y direction z direction A Cutting direction

Claims

[1] Multi-aperture array (350) for manipulating a plurality of charged first single-element beams (3) comprising the following: A base body (360) with a plurality of apertures (351), wherein in the operation of the multi-aperture array (350) one of the charged first single-particle beams (3) passes through each aperture (351); at least a plurality of first electrodes (82), wherein one of the first electrodes (82) is arranged at each of the apertures (351) in order to individually influence the first single particle beam (3) passing through the aperture (351), and wherein each of the first electrodes (82) is connected to a control unit (10); wherein the base body (360) has a first depth TG in a z-direction along which the first apertures (351) extend through the base body (360); wherein the first electrodes (82) each have a depth TE in the z-direction which is less than the depth TG, i.e. TE < TG; wherein the first electrodes (82) are each embedded in the base body (360) such that they are exposed in a region adjacent to and forming the aperture (351) and are otherwise embedded directly in the base body (360) without an electrical insulating layer; and wherein the material of the base body (360) is glass or consists of glass. [2] Multi-aperture array (350) according to the preceding claim, wherein each of the first electrodes (82) is connected to an associated first conductor track (86) within the base body (360); and wherein the first conductor tracks (86) are each directly embedded in the base body (360), in particular completely. [3] Multi-aperture array (350) according to the preceding claim, wherein each of the first conductor tracks (86) in the base body (360) is angled and extends on one side in the z-direction and on the other side in a direction orthogonal to the z-direction. [4] Multi-aperture array (350) according to any one of the preceding claims, wherein the base body (360) has a top surface (370) which, in the operation of the multi-aperture array (350), is oriented in the direction of entry of the charged first single-particle beams (3), wherein the top surface (370) of the base body (360) has an upper discharge layer (371) made of a material with high conductivity, so that charging of the base body (360) is avoided during operation of the multi-aperture array (350). [5] Multi-aperture array (350) according to the preceding claim, wherein a short-circuit protection layer (372) is provided on the base body (360) within the apertures (351), which extends from the top (370) of the base body (360) with the upper discharge layer (371) to the first electrode (82) and which has or consists of a material with low conductivity, so that a short circuit between the upper discharge layer (371) and the electrode (82) is avoided during operation of the multi-aperture array (350). [6] Multi-aperture array (350) according to any one of the preceding claims, wherein the base body (360) has a bottom surface (380) which, in the operation of the multi-aperture array (350), is oriented in the exit direction of the charged first single-particle beams (3) from the multi-aperture array (350), wherein the underside (380) of the base body (360) has a lower discharge layer (381) made of a material with high conductivity, so that charging of the base body (360) is avoided during operation of the multi-aperture array (350). [7] Multi-aperture array (350) according to the preceding claim, wherein a short-circuit protection layer (382) is provided on the base body (360) within the apertures (351), which extends from the underside (380) of the base body (360) with the lower discharge layer (381) to the first electrode (82) and which has or consists of a material with low conductivity, so that a short circuit between the lower discharge layer (381) and the electrode (82) is avoided during operation of the multi-aperture array (350). [8] Multi-aperture array (350) according to one of the preceding claims, wherein the base body (360) is formed in one piece. [9] Multi-aperture array (350) according to one of claims 1 to 7, wherein the base body (360) is formed in multiple parts. [10] Multi-aperture array (350) according to one of the preceding claims, wherein the first electrodes (82) are designed as ring electrodes (81). [11] Multi-aperture array (350) according to any one of claims 1 to 9, which furthermore has a large number of second and / or additional electrodes (82), wherein one of the second and / or further electrodes (82) is arranged at one of the apertures (351) in order to individually influence the first single particle beam (3) passing through the aperture (351), and wherein each of the second and / or further electrodes (82) is connected to a control unit (10); wherein the second and / or further electrodes (82) each have a depth TE2, TEi in the z-direction which is less than the depth TG, i.e. TE2 < TG or TEi < TG; and wherein the second and / or further electrodes (82) are each embedded in the base body (360) such that they are free in an area adjacent to and forming the aperture (351) and are otherwise embedded directly in the base body (360) and thus without an electrical insulating layer. [12] Multi-aperture array (350) according to the preceding claim, wherein a deflection unit is provided in each of the apertures (351) by means of the electrodes (82) surrounding them. [13] Multi-aperture array (350) according to one of claims 11 to 12, wherein a stigmatization unit is provided in each of the apertures (351) by means of the electrodes (82) surrounding them. [14] Multi-aperture array (350) according to one of the preceding claims, wherein the base body (360) comprises or consists of one of the following materials: silicate glass, borate glass, borosilicate glass. [15] Multi-aperture array (350) according to one of the preceding claims, wherein the material of the base body (360) consists of Borofloat®. [16] Multi-aperture array (350) according to any one of the preceding claims, wherein the multi-aperture array (350) has a support element (390); and wherein the base body (360) is arranged on the support element (390) and connected to the support element (390). [17] Multi-aperture array (350) according to the preceding claim, wherein the material of the support element (390) comprises silicon or consists of silicon. [18] Multi-aperture array (350) according to the preceding claim, wherein the support element (390) has a plurality of conductor tracks (391) which are arranged completely within the support element (390); and wherein the conductor tracks (391) are indirectly embedded in the carrier element (390) and surrounded by an insulating layer. [19] Multi-aperture array (350) according to claims 2 and 18, wherein the base body (360) and the support element (390) together form a combination unit; wherein at least one contact pad (389) is arranged in a connection area between the base body (360) and the support element (390) per aperture (351), wherein each contact pad (389) connects one of the conductor tracks (86) within the base body (360) to one of the conductor tracks (391) within the support element (390); and wherein each contact pad (389) is completely arranged within and embedded in the combination unit. [20] Multi-aperture array (350) according to claim 16, wherein the material of the support element (390) comprises or consists of glass. [21] Multi-aperture array (350) according to the preceding claim, wherein the support element (390) has a plurality of conductor tracks (391) which are arranged completely within the support element (390); and wherein the conductor tracks (391) are directly embedded in the support element (390). [22] Multi-aperture array (350) according to claims 2 and 21, wherein the base body (360) and the support element (390) together form a combination unit; wherein at least one contact pad (389) is arranged in a connection area between the base body (360) and the support element (390) per aperture (351), wherein each contact pad (389) connects one of the conductor tracks (86) within the base body (360) to one of the conductor tracks (391) within the support element (390); and wherein each contact pad (389) is completely arranged within the combination unit and directly embedded in the combination unit. [23] Multi-aperture array (350) according to any one of claims 16 to 22, wherein the support element (390) has a top surface (392) which, in the operation of the multi-aperture array (350), is oriented in the direction of entry of the charged first single-particle beams (3), and wherein the top surface (392) of the support element (390) has a conduction layer (393) made of a material with high conductivity, so that charging of the support element (390) is avoided during operation of the multi-aperture array (350). [24] Multi-aperture array (350) according to any one of claims 16 to 23, wherein the support element (390) has a bottom surface (394) which, during operation of the multi-aperture array (350), is oriented in the exit direction of the charged first single-particle beams (3) from the multi-aperture array (350), wherein the underside (394) of the support element (390) has a conduction layer (395) made of a material with high conductivity, so that charging of the support element (390) is avoided during operation of the multi-aperture array (350). [25] Multi-aperture array (350) according to one of claims 16 to 24, wherein the support element (390) is set back from the base body (360) in the area of ​​the apertures (351). [26] Multi-particle beam system (1) comprising at least one multi-aperture array (350) according to any one of the preceding claims. [27] Multi-particle beam system (1) according to claim 26, wherein the multi-particle beam system (1) is a multi-beam particle microscope (1). [28] A multiple particle beam system (1) according to claim 26, wherein the multiple particle beam system (1) is a lithography system.

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