Particle beam system

Abstract

A particle beam system includes: a multi-beam particle source configured to generate a plurality of particle beams; an imaging optics unit configured to image an object plane onto an image plane in a particle optical manner and guide the plurality of particle beams onto the image plane; and a field generation arrangement configured to generate electric and / or magnetic deflection fields in a region near the object plane, wherein the particle beams are deflected by the deflection fields during operation, the deflection angle depending on the intensity of the deflection fields.

Description

[0001] background Technical Field

[0002] The present invention relates to a particle beam system operating using multiple particle beams. Background Art

[0003] For example, WO 2005 / 024881 A2 and DE 10 2014 008 083 B4 disclose an electron microscope system utilizing a plurality of electron beam operations, so as to scan the object to be inspected by the electron beam parallel scanning.Electron beam is an electron beam produced by an electron source and is directed to a porous plate with a plurality of openings and is produced.A part of electrons of the electron beam impinges on the porous plate and is absorbed there, and another part of electrons passes through the opening of the porous plate, so that the electron beam is shaped on the beam path downstream of each opening, and the cross section of the electron beam is limited by the cross section of the opening.In addition, the electric field of the appropriate selection provided on the path upstream and / or downstream of the porous plate has the following effect: each opening of the porous plate plays the role of a lens to the electron beam passing through the opening, so that actual or virtual focus occurs in the plane outside the porous plate.The plane formed with the focus of the electron beam is imaged on the surface of the object to be inspected by an imaging optical unit, so that each electron beam is impacted on the object as a primary beam side by side in a focused manner. There, the electron beam generates backscattered electrons or secondary electrons from the object, which are shaped to form secondary beams and directed via further imaging optics to a detector array. At the detector, each secondary electron beam impinges on a separate detector element so that the electron intensity detected by the detector element provides information about the object at the location where the corresponding primary electron beam impinges on the object. A plurality of primary electron beams are systematically scanned in parallel over the surface of the object in order to produce an electron micrograph of the object in the conventional manner of a scanning electron microscope.

[0004] It has been found that the electron micrographs obtained by means of the individual electron beams, in particular in the case of objects with very large structures, depend on the position occupied by the respective electron beam within the plurality of electron beams. The inventors attribute this to the fact that the individual electron beams do not all strike the object orthogonally, but strike the object at different angles, wherein the angle at which a given electron beam strikes the object depends on the position of said electron beam within the electron beam. The inventors therefore realized that the imaging of the plane forming the focus of the electron beam on the object is not telecentric. It is therefore desirable to influence the telecentricity of the imaging of the focal plane onto the object. Since the telecentricity error generally increases with increasing distance from the center of the image field, it is also desirable to influence the size of the irradiation field on the object by means of a variable distance between the individual beams at the object. Summary of the invention

[0005] It is therefore an object of the present invention to specify a particle beam system which operates with a plurality of particle beams and in which the angles and distances between the particle beams within the particle beam can be influenced.

[0006] According to an embodiment of the present invention, the particle beam system includes a multi-beam particle source, which is configured to produce a plurality of particle beams. The multi-beam particle source may include, for example, a particle emitter and a porous plate for producing a particle beam, the porous plate being arranged on the beam path of the particle beam and having a plurality of openings, the particles of the particle beam passing through these openings, so that a plurality of particle beams are produced on the beam path downstream of the porous plate.

[0007] The particle beam system further comprises an imaging optical unit configured to particle optically image the object plane into an image plane and to direct the plurality of particle beams onto the object plane. Imaging the object plane into the image plane does not exclude one or more intermediate image planes in which an image of the object plane is generated, also arranged on the beam path between the object plane and the image plane.

[0008] The particle beam system further comprises a field generating arrangement configured to generate an electric and / or magnetic deflection field of adjustable strength in a region near the object plane, wherein the particle beam is deflected by the deflection field during operation, the deflection angle being dependent on the strength of the deflection field.

[0009] The particle beam system allows the angle at which the particle beam passes through the image plane to be affected by setting the deflection angle near the object plane.

[0010] The deflection angle of each particle beam deflected by the deflection field can be determined as the angle between two straight lines, wherein one of the two straight lines is consistent with the trajectory of the particle beam on the beam path directly upstream of the deflection field, and the other of the two straight lines is consistent with the trajectory of the particle beam on the beam path directly downstream of the deflection field. If the particle beam is not deflected by the deflection field, the deflection angle is zero in this case. The deflection field extends in the direction of the beam path over a wide area. Therefore, the deflection field acts on the particle beam over a wide area and has the effect that the trajectory in the deflection field region extends along a curved path.

[0011] The object to be irradiated with the particle beam can be arranged in the image plane. The focus of the particle beam that can be formed on the beam path of the particle beam described above can also be produced in or near the object plane. However, the particle beam system is not limited to this configuration.

[0012] The deflection field of the field generating arrangement is generated on the beam path in the vicinity of an object plane, which is imaged onto the image plane by the imaging optical unit. The arrangement in the vicinity of the object plane comprises the fact that the distance between the plane in which the effect of the deflection field can be located and the actual object plane imparted to the image plane by the imaging optical unit, on which the object is arranged, is less than 0.1 times, in particular less than 0.05 times, the distance between the object plane and the image plane.

[0013] As explained above, the deflection field extends in the direction of the beam path of the particle beam to deflect over a wide area. The deflection effect of the deflection field on the particle beam can be localized to a plane in which the vertex of the deflection angle (if the deflection angle is determined as described above) is arranged, for example.

[0014] If the particle beam that passes through the field generation arrangement is arranged to be deflected by the field generation different deflection angles, the deflection angle depends on the intensity of the deflection field that produces for this particle beam, so the effect that this variation of the deflection angle has in the image plane is that only the angle change of the corresponding particle beam impacts the image plane, and the incident position of the particle beam on the image plane can not change because of the variation of the deflection angle basically.By setting the deflection field, therefore the angle of the particle beam impacting the image plane can be set in a targeted manner.Especially, then the deflection field can be excited in such a way that all particle beams of a plurality of particle beams are incident on the image plane orthogonally, i.e. telecentrically.The effect that has like this is, when being used as the particle beam system of microscope, even when in the situation of large structured object, the image captured by each particle beam does not significantly depend on the position of the corresponding particle beam in the particle beam.

[0015] For particle beam systems using multiple particle beam operations, the conventional approach is to use a magnetic objective lens, which is designed so that the focusing magnetic field acts on the particle beam only in the lens body, and the magnetic leakage field extending from the lens body to the object is as small as possible. According to an exemplary embodiment of the present invention, the particle beam system includes the above-mentioned field generation arrangement and an imaging optical unit including an objective lens, and the objective lens provides a focusing magnetic field with a magnetic field strength greater than 20mT, particularly greater than 50mT, particularly greater than 150mT at the image plane. This objective lens is traditionally referred to as a magnetic immersion lens. The magnetic immersion lens is usually realized by a hole in the outer pole shoe of the lens, and the diameter of the hole is greater than the hole in the inner pole shoe of the lens. Compared with an objective lens that only provides a low magnetic field at the object, these lenses have the advantage of being able to achieve lower spherical aberration and chromatic aberration, and also have the disadvantage of greater off-axis aberration. On the other hand, the strong magnetic field present on the surface of the object has the following effect: the particle beam that hits the object and is at a certain distance from the optical axis of the objective lens is not orthogonally incident on the object, so the particle beam does not orthogonally emit from the object starting from the object, which can cause problems in the case of large structured objects. The use of a field generating arrangement now allows the particle beams to be deflected near the object plane so that they are incident orthogonally on the object despite the presence of a magnetic field on the surface of said object. In addition, this also compensates for the off-axis aberrations of the immersion lens, which usually constitute a disadvantage of immersion lenses. In particular, said off-axis aberrations usually increase linearly with the distance from the optical axis. Similarly, the angular deviation from the orthogonal incidence of the beam on the object plane, i.e. the telecentricity error, also increases proportionally with the distance from the optical axis. Calculations have shown that by correcting the telecentricity error, the off-axis aberrations are also greatly reduced at the same time. It is therefore possible to use so-called immersion lenses in multi-beam particle systems, whose beams are incident on the object at a certain distance from the optical axis of the objective, and to fully exploit their aberration-reducing possibilities.

[0016] Since each particle beam is focused onto the object plane, the trajectories of the particles of a given particle beam converge towards the object plane. This means that even in the case of a particle beam incident orthogonally onto the object plane, the trajectories of the particles incident on the object plane are not all oriented orthogonally to the object plane. However, the angle of incidence of a particle beam on a plane is usually determined based on the so-called centroid ray of the particle beam. The centroid ray represents the imaginary sum of the trajectories of all particles of the particle beam.

[0017] According to an exemplary embodiment, a multi-beam particle source comprises a plurality of particle emitters arranged side by side with each other near an object plane, and each particle emitter generates one particle beam or a plurality of particle beams in a plurality of particle beams. In this case, the field generating arrangement may comprise a magnetic coil configured to generate a magnetic field, the particle emitters being arranged in the magnetic field, and the field direction of the magnetic field in the object plane being oriented to be orthogonal to the object plane.

[0018] The inventors have also realised that telecentricity errors in the imaging of incident field positions at the object onto the deflector array have the effect that the image obtained using individual particle beams depends on the position occupied by the respective particle beam in the particle beam field.

[0019] According to another exemplary embodiment of the present invention, the particle beam system therefore comprises: an irradiation system, which is configured to guide a plurality of particle beams onto an object plane so that the particle beams irradiate a plurality of incident positions; and an imaging optical unit, which is configured to guide a plurality of particle beams emitted from the object plane onto a detector array. In this case, the detector array can be arranged in an image plane, into which the object plane is imaged by the imaging optical unit in a particle optical manner. The imaging optical unit images the object plane into an intermediate image plane and generates an image of the object plane there. The particle beam system also comprises a field generating arrangement, which is configured to generate an electric and / or magnetic deflection field of adjustable strength in a region near the intermediate image plane, wherein the particle beam is deflected by the deflection field during operation, and the deflection angle depends on the strength of the deflection field.

[0020] If the telecentricity of a particle beam starting in the object plane is disturbed, for example, by local electric fields, i.e., if individual particle beams move away from the object plane in a direction oriented not orthogonal to the object plane, this can have the following effect: a particle emitted from a given incident position at the object does not strike that detector element of the detector array assigned to the incident position, but rather strikes an adjacent detector element different from the detector element. The signal detected by the adjacent detector element may then be erroneously not assigned to the given incident position. This problem is often referred to as "crosstalk" between particle beams. In order to reduce this problem, an aperture is usually used which is arranged in the beam crossing region of the particle beam between the object and the detector array. The aperture absorbs particles moving on trajectories which lead to a detector element which is not assigned to the incident position from which the particle was emitted. In order to achieve reliable filtering, the opening diameter of the aperture should be chosen to be as small as possible. However, this presupposes that all beams passing through the plane in which the aperture is arranged start from the object plane at essentially the same angle. However, what may actually happen is that the particle beams emanating from the incident position start from the object at a plurality of angles, which angles depend on the position of the respective particle beam within the particle beam.

[0021] The effects of these angles on the particle beam trajectory may be affected by and partially compensated for by deflections of the particle beam as it passes through the field generation arrangement.

[0022] The field generating arrangement arranged in the imaging optical unit between the object and the detector array may have a structure that is the same as or similar to the structure of the field generating arrangement arranged in the beam path between the particle sources of the object.

[0023] The arrangement near the intermediate image plane includes the fact that the distance between the plane in which the effect of the deflection field can be located and the actual intermediate image plane imaged by the imaging optical unit into which the object plane with the object is arranged is less than 0.1 times, in particular less than 0.05 times, the distance between the object plane and the intermediate image plane.

[0024] According to an exemplary embodiment of the present invention, a particle beam system comprises the above-mentioned field generating arrangement and an imaging optical unit comprising an objective lens, which provides a focusing magnetic field with a magnetic field strength greater than 20mT, particularly greater than 50mT, particularly greater than 150mT at the image plane.

[0025] According to an exemplary embodiment, the field generating arrangement is configured such that the side of the deflection angle of the one particle beam deflected by the field generating arrangement is located in a plane whose normal is at a distance from the optical axis of the imaging optical unit that is less than 0.99 times, in particular less than 0.95 times, in particular less than 0.90 times, of the distance between the vertex of the deflection angle and the main axis. This means that the deflection of the beam is not only achieved towards or away from the main axis, i.e. in a radial direction relative to the main axis, but that at least one component of the deflection is oriented in a circumferential direction relative to the main axis.

[0026] In this case, the optical axis of the imaging optical unit extends along the symmetry axes of the rotationally symmetric lenses of the imaging optical unit, which are arranged one behind the other in the beam path. In this case, the optical axis of the imaging optical unit can also include a plurality of straight line regions which are not arranged on a common straight line. This is the case, for example, if a non-rotationally symmetric beam deflector is arranged between two rotationally symmetric lenses.

[0027] The above-mentioned distance relationship between the normal line of the plane of two limits of optical axis and the deflection angle means that the deflection of the particle beam of deflection is not only realized towards or away from the optical axis, that is, realizes in radial direction with respect to the optical axis. Instead, at least one important component of the deflection is required to realize in the circumferential direction around the optical axis extending through the deflection arrangement. For example, during the operation of the particle beam system, the particle beams that exceed 30% or exceed 60% can satisfy this relationship.

[0028] Furthermore, the deflection angle may be greater than 10 μrad, in particular greater than 50 μrad, in particular greater than 100 μrad, in particular greater than 300 μrad. During operation of the particle beam system, for example more than 30% or more than 60% of the particle beams may also satisfy this relationship.

[0029] According to an exemplary embodiment, the deflection field is generated in such a way that for a plurality of pairs of a plurality of particle beams passing through the object plane or the intermediate image plane, the following relations hold:

[0030] 0.9<r1 / r2*α2 / α1<1.1

[0031] in

[0032] r1 represents the radial distance between the position where the first particle beam of the pair passes through the object plane or the intermediate image plane and the center of this plane,

[0033] r2 represents the radial distance between the position where the second particle beam of the pair passes through the object plane or the intermediate image plane and the center of this plane,

[0034] α1 represents the absolute value of the deflection angle of the first particle beam deflection, and

[0035] α2 represents the absolute value of the deflection angle of the second particle beam deflection.

[0036] This means that the size of the deflection angle increases substantially linearly with the distance from the center or optical axis.

[0037] The deflection of the particle beam in the object plane by a deflection angle oriented in a circumferential direction around the optical axis of the illumination system also has the effect of enlarging the cross section of the entire particle beam in a plane generally specified by the cross, in which the cross section of the particle beam is minimum. This in turn reduces the mutual repulsion of the particles from one another due to Coulomb repulsion, which in turn enables a smaller beam focus to be achieved in the image plane, thereby improving the resolving power of the multi-beam particle microscope.

[0038] According to an exemplary embodiment, the field generating arrangement comprises a deflector array having a plurality of deflectors arranged side by side with one another, wherein a group of particle beams passes through each deflector during operation. An embodiment of a suitable deflector array is described, for example, in the German patent application with application number 10 2018 202 421.9, the disclosure of which is incorporated in its entirety in the present application.

[0039] According to an exemplary embodiment, the deflectors in the deflector array include at least one pair of electrodes positioned opposite to each other, between which the particle beam passes through the deflector. The particle beam system may include a controller configured to apply different potentials to the electrodes. The number of pairs of electrodes positioned opposite to each other may in particular be equal to one or two.

[0040] According to an exemplary embodiment, only one pair of opposing electrodes is provided at each deflector. In this case, a straight line extending through the centers of the two electrodes can be oriented in such a way that it extends in a circumferential direction relative to the center of the deflector array. With such a deflector array, for example, a particle beam can be influenced whose trajectories extend helically around a main axis passing through the center, so that these trajectories extend parallel to the main axis after passing through the deflector array.

[0041] According to an exemplary embodiment, each deflector includes a first plate and a second plate, which are arranged one behind the other on the beam path, wherein the first plate and the second plate each have an opening, and the particle beams in the group of particle beams pass through the openings one after another. In this case, the center of the opening of the first plate is laterally offset relative to the center of the opening of the second plate in the direction of the beam path. Then, the particle beam system may include a controller, which is configured to apply mutually different potentials to the first plate and the second plate. Then an electric field is generated between the first plate and the second plate, and the electric field causes the particle beam passing through the opening to be deflected.

[0042] According to an exemplary embodiment herein, the deflector array comprises a first porous plate having a plurality of first openings, and a second porous plate having a plurality of second openings, wherein each group of particle beams successively passes through one of the first openings and one of the second openings, respectively. In this case, the first openings passed through and the second openings passed through are again arranged in a manner laterally offset relative to each other, as seen in the direction of the beam path.

[0043] According to a further exemplary embodiment, the deflector array comprises a center, wherein the center of the first opening is laterally offset relative to the center of the second opening in a circumferential direction with respect to the center of the deflector array, seen in the direction of the beam path.

[0044] An embodiment of such a deflector is described, for example, in the international patent application WO 2007 / 028596 A1, the disclosure content of which is incorporated in the present application.

[0045] The number of particle beams in a group of particle beams deflected by a deflector in the deflector array may be two, three or more. According to an exemplary embodiment, each group comprises only a single particle beam, so that a separate deflector in the deflector array is provided for each particle beam in the plurality of particle beams.

[0046] According to another embodiment of the present invention, the particle beam system includes an irradiation system, which is configured to guide multiple particle beams to the object plane so that the particle beam irradiates the incident field position. The irradiation system includes a porous plate, which is arranged on the beam path of the particle beam and has multiple openings, wherein the particle beam passes through each opening, and a first single-hole plate has an opening, and multiple particle beams pass through the opening, wherein the first single-hole plate is arranged to be a first distance from the porous plate. The irradiation system also includes a second single-hole plate with an opening, and multiple particle beams pass through the opening, wherein the second single-hole plate is arranged to be a second distance from the porous plate. The particle beam system includes a voltage source, which is configured to apply an adjustable first potential to the first single-hole plate relative to the porous plate and to apply an adjustable second potential to the second single-hole plate relative to the porous plate, wherein the first distance is less than 0.5 times of the second distance, particularly less than 0.2 times of the second distance, particularly less than 0.1 times of the second distance.

[0047] With a particle beam system configured in this manner, the effects of telecentricity errors during irradiation of an object with multiple particle beams may also be affected by making the diameter of the particle beam field variable at the object. This variation can be achieved by varying the potential applied by the voltage source to the first single aperture plate and the second single aperture plate.

[0048] Due to the difference between the potential applied to porous plate and single hole plate, electric field is produced at the porous plate and electric field has the following effect: the opening of the porous plate has a lens effect to the particle beam passing through it, so that the particle beam passing through the opening forms a beam focus on the beam path of the porous plate downstream or upstream. The beam focus can be imaged on the plane arranged with object by an imaging optical unit. This imaging on the object plane generally includes an imaging aberration that is called field curvature. In order to at least partially compensate for this aberration, the electric field adjacent to the porous plate can be produced in this way so that the beam focus is located on a curved surface rather than on a plane. This example is described in International Patent Application WO 2005 / 024881 A2, and its disclosure is incorporated in the present application as a whole.

[0049] The above-mentioned particle beam system can not only influence the curvature of the surface on which the generated beam foci are arranged, but also change the distances between the beam foci. The changes in these distances then directly cause changes in the distances between the incident positions of the particle beam in the object plane, and therefore cause changes in the diameter of the particle beam field in the object plane.

[0050] In this case, a change in voltage between the porous plate and the first single-hole plate substantially causes a change in the curvature of the surface where the beam foci are arranged, whereas a change in voltage between the porous plate and the second single-hole plate mainly causes a change in the distance between the beam foci.

[0051] According to an exemplary embodiment, the diameter of the opening in the second single orifice plate is 1.5 times or three times larger than the diameter of the opening in the first single orifice plate.

[0052] According to an exemplary embodiment, the first single-well plate and the second single-well plate are arranged on the same side with respect to the multi-well plate. According to a further exemplary embodiment, the multi-well plate is arranged between the first single-well plate and the second single-well plate.

[0053] According to another exemplary embodiment, at least one third single-hole plate is provided, the third single-hole plate having an opening through which a plurality of particle beams pass, wherein the third single-hole plate is arranged at a third distance from the porous plate, the third distance being greater than the second distance. At least one third single-hole plate is arranged on the same side as the second single-hole plate with respect to the porous plate. The voltage source can apply a potential to the at least one third single-hole plate in such a way that the third single-hole plate acts on the particle beam together with the second single-hole plate as a lens with adjustable refractive power to change the distance between the beam foci.

[0054] Due to the above-mentioned geometric design of the single-hole plate, i.e. due to the selection of the distance between the single-hole plate and the porous plate and the selection of the diameter of the opening of the single-hole plate, the curvature of the surface formed with the beam focus can be changed, and the distance between the beam focuses can be set in a manner that is largely separated from each other. Therefore, a controller can be provided, which is configured to receive a first input signal representing the desired curvature of the surface arranged with the beam focus, and to receive a second input signal representing the desired distance between the incident positions of the particle beam in the object plane. Then, the controller can be configured to change the potential difference between the porous plate and the first single-hole plate by a voltage source according to the first input signal, and to change the potential difference between the porous plate and the second or third single-hole plate by a voltage source based on the second input signal.

[0055] According to another embodiment of the present invention, a particle beam system includes an irradiation system configured to direct a plurality of particle beams onto an object plane so that the particle beams irradiate incident field positions. In this case, the irradiation system includes: a multi-beam particle source having a particle emitter configured to generate a particle beam; at least one condenser lens through which the particle beam passes; a first porous plate arranged on a beam path of the particle beam downstream of the condenser lens and having a plurality of openings through which particles of the particle beam pass, so that a plurality of particle beams are formed on the beam path downstream of the first porous plate. The irradiation system also includes a second porous plate arranged on a beam path downstream of the first porous plate and having a plurality of openings, wherein each of the openings is passed through a particle beam of the plurality of particle beams. The irradiation system also includes a controller configured to excite at least one condenser lens so that the condenser lens provides an adjustable refractive power for the particle beam to receive a first signal representing a desired distance between incident positions of the particle beam in the object plane, and to change the refractive power of at least one condenser lens when the first signal changes.

[0056] The change of the refractive power of the condenser lens caused by the excitation change of the condenser lens causes the change of the divergence of the particle beam incident on the first porous plate, and therefore also causes the change of the divergence of a plurality of particle beams produced on the beam path downstream of the porous plate. These plurality of particle beams are eventually directed to the object. Obviously, when the characteristic of the irradiation optical unit remains unchanged, the increase of the divergence of a plurality of particle beams directly downstream of the first porous plate causes the increase of the distance between the incident positions of the particle beam on the object, and the reduction of the divergence of a plurality of particle beams directly downstream of the first porous plate causes the distance between the incident positions of the particle beam on the object to decrease accordingly.

[0057] According to an exemplary embodiment, the irradiation system is configured to focus the particle beam on the beam path downstream of the porous plate and upstream of the object plane, respectively, wherein the corresponding beam focus is arranged on the curved surface. In this case, the particle beam system also includes a single-hole plate, which is arranged on the beam path upstream or downstream of the second porous plate and has an opening through which a plurality of particle beams pass. Then, the controller can be configured to provide an adjustable potential difference between the single-hole plate and the porous plate to receive a second signal representing the desired curvature of the surface, and to change the potential difference between the single-hole plate and the porous plate when the second signal changes. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] The above features and the advantages of the features will become more apparent from the following description of the embodiments. However, embodiments of the present invention need not include all of the features described, and any features that may be included do not necessarily show all of the advantages described. In the accompanying drawings:

[0059] Figure 1 A schematic diagram of a particle beam system is shown;

[0060] Figure 2 Shows Figure 1 A schematic illustration of details of a particle beam system;

[0061] Figure 3 Shows the available Figure 1 A schematic illustration of a plan view of a deflector array of a particle beam system;

[0062] Figure 4 A diagram is shown for illustrating the orientation of the particle beam deflection, which is achieved by Figure 1 The field generation arrangement of the particle beam system in the particle beam system is generated;

[0063] Figure 5 A schematic diagram showing a plan view of another deflector array that can be used Figure 1 Particle beam systems;

[0064] Figure 6 Shows Figure 5 The deflector array shown in FIG. Figure 5 Schematic illustration of a cross-sectional view along line VV in FIG.

[0065] Figure 7 Shows the available Figure 1 A schematic illustration of a cross-sectional view of a detail of a multi-beam particle source of a particle beam system;

[0066] Figure 8 Schematic illustration of a cross-sectional view showing a detail of another multi-beam particle source that can be used Figure 1 Particle beam system.

[0067] Fig. 9 Schematic illustration of a cross-sectional view showing a detail of another multi-beam particle source that can be used Figure 1 Particle beam system.

[0068] Fig.10 Schematic illustration of a cross-sectional view showing a detail of another multi-beam particle source that can be used Figure 1 Particle beam system. DETAILED DESCRIPTION

[0069] In the following description of the embodiments, components that are similar in structure and function are largely provided with the same or similar reference numerals. In order to fully understand the meaning of the individual features, the description of other features with similar reference numerals and the description of these and other features in the "Summary of the Invention" section should also be considered.

[0070] exist Figure 1 Schematically illustrates a particle beam system according to an embodiment. The particle beam system 1 includes an irradiation system 3, which is configured to direct a plurality of particle beams 5 onto a plane 7, in which an object 9 is arranged. Each particle beam 5 irradiates an incident position on the object 9, wherein the particle beams 5 are incident on the object 9 side by side and at a distance from each other, so that the incident field is irradiated there. The particle beam 5 can be, for example, an electron beam, which generates secondary electrons and backscattered electrons at the object 9. The imaging optical unit 11 of the detection system is configured to collect the electrons generated at the incident position and guide them to a detector array 13. Here, the electrons emitted from each incident position are used to shape a separate particle beam 15 in each case. The particle beam 15 is guided to the detector array 13. The detector array 13 includes an array of detector elements, wherein one or more detector elements are provided for detecting a corresponding one of the particle beams 15. For this purpose, the detector elements are arranged in an array corresponding to the incident position arrangement at the object 9. The imaging optical unit 11 is configured relative to the surface of the object 9 and the detector array 13 such that the surface of the object 9 is arranged in an object plane 17 of the imaging provided by the imaging optical unit 11 and the detector elements of the detector array 13 are arranged in an image plane 19 of the imaging. The imaging optical unit 35 of the illumination system 3 and the imaging optical unit 11 of the detector system are arranged such that the image plane 7 of the imaging optical unit 35 and the object plane of the imaging optical unit 11 coincide and the surface of the object can be arranged there. The plane 7 is therefore the image plane of the illumination system 3, the object plane 17 of the imaging optical unit 11 and the sample plane in which the surface of the object to be inspected is arranged.

[0071] The irradiation system 3 comprises a multi-beam particle source 21 having a particle emitter 22 for generating a particle beam 23, which is collimated by one or more condenser lenses 25 and strikes a porous plate arrangement 27. The porous plate arrangement 27 comprises at least one porous plate with a plurality of openings. The particles of the particle beam 23 passing through the openings in the porous plate form a particle beam 5. The porous plate arrangement 27 is also configured to focus each particle beam 5 so that a focus 31 of the particle beam 5 is formed in the area around the surface 29. In this case, the surface 29 can have a curved shape. Another lens 33 that affects the beam path can be provided between the porous plate arrangement 27 and the surface 29.

[0072] The illumination system 3 further comprises an imaging optical unit 35, which is configured to image the surface 29 into the plane 7, so that the surface 29 and the plane 7 are planes that are conjugate with respect to each other in the sense of optical imaging. The imaging optical unit 35 comprises an objective lens 37, which is the lens of the imaging optical unit 35 that is arranged closest to the plane 7. In addition, the imaging optical unit 35 may comprise a further lens 39.

[0073] The irradiation system 3 guides the particle beam 5 onto the plane 7 in such a way that the particle beam is incident on the plane 7 orthogonally as far as possible, i.e., with an incident angle of 90 °. However, due to the characteristics of the lenses 37 and 39, a deviation from this relationship is produced, so that the particle beam is incident on the plane 7 with an incident angle different from 90 °. In particular, these directions are not the same for all particle beams 5, but can depend on the position of the corresponding particle beam 5 in the particle beam field. For example, the deviation of the incident angle from 90 ° may be caused by the telecentricity error of the imaging optical unit 35. In addition, the objective lens 37 can provide its focusing effect by the magnetic field reaching the surface of the object 9. The trajectory of the particle beam directly at the surface of the object then has a spiral shape. In order to at least partially compensate for this deviation from telecentricity, a deflector array 41 is arranged near the surface 29, and the surface is imaged into the plane 7.

[0074] exist Figure 3 A plan view of an embodiment of a deflector array 41 is schematically shown in FIG. The deflector array 41 includes a porous plate 43 having a plurality of openings 45 arranged in an array 46 in such a manner that one of the particle beams 5 passes centrally through each opening 45. At each opening 45, a pair of electrodes 47 are arranged opposite to each other on both sides of the midpoint of the opening 45. Each electrode 47 is connected to a controller 49, which is configured to apply mutually different potentials to the electrodes 47 in each pair of electrodes. The potential difference between the electrodes 47 in a pair of electrodes 47 generates an electric field between the electrodes 47, and the electric field deflects the particle beam 5 passing through the pair of electrodes 47 by an angle depending on the potential difference.

[0075] The electrode pairs 47 are oriented in such a way relative to the particle beam 5 passing through the latter that a connecting line 51 between the centers of the two electrodes 47 of the pair is arranged in a circumferential direction relative to the center 53 of the array 46 of openings 45 through which the particle beam 5 passes. As a result, the particle beam 5 can be deflected so that after passing through the deflector array 41, the particle beam extends on a spiral path around the center 53 of the field of the particle beam 5. The inclination of these spiral paths can be set here so that the effect of the magnetic field extending from the objective lens 37 as far as the surface of the object 9 is compensated, with the result that the particle beam 5 is incident on the plane 7 essentially orthogonally.

[0076] exist Figure 3 In the case of the deflector array 41 shown, each deflector has a pair of electrodes 47, which are arranged in a circumferentially offset manner relative to the center 53. Thus, the particle beam can be deflected in a circumferentially oriented direction relative to the center. However, two or more pairs of electrodes that are relative to each other can also be arranged in a circumferential direction around the opening in a distributed manner so that the orientation of the particle beam passing through these multiple pairs of electrodes can also be set.

[0077] Figure 4 4 is a diagram for explaining the orientation of the particle beam deflection, which is produced by the field generating device 41 .

[0078] Figure 4 The plane 201 in FIG. 4 represents the plane in which the effect of the deflection field of the field generating arrangement 41 can be located. The particle beam 5 enters the field generating arrangement 41 from above and passes through Figure 4 The particle beam 5 is emitted from the field generating device 41 at the bottom. The trajectory of the particle beam 5 extends straightly on a curved path before entering the field generating arrangement 41 and after being emitted from the field generating arrangement 41 and within the field generating arrangement 41. The extensions 203 and 204 of the straight portion of the trajectory intersect at point 205 and form an angle α with each other. Angle α is the deflection angle of the particle beam 5 deflected by the deflection field of the field generating arrangement 41. The straight extensions 203 and 204 form the edges of the deflection angle α, and point 205 is the vertex of the deflection angle. The edges 203 and 204 are located in a plane 207. The plane 207 is oriented to be orthogonal to the plane 201, and the effect of the deflection field of the field generating arrangement 41 can be located in this plane. The vertex 205 of the deflection angle is at a distance r from the center 53 of the field generating arrangement 41. Advantageously, the optical axis 209 of the imaging optical unit 35 passes through the center 53 of the field generating arrangement 41. With respect to the center 53 or the optical axis 209 of the imaging optical unit 35, the plane 207 has the following orientation: a distance d from the optical axis of a straight line 211 oriented orthogonally to the plane 207 and passing through the vertex 205 at the deflection angle α is less than 0.99 times, 0.95 times, or 0.90 times the distance r between the vertex 205 and the optical axis 209 or the center 53. This means that the particle beam 5 is deflected by a deflection angle α, which is also oriented in the circumferential direction relative to the optical axis 209.

[0079] Figure 4 Likewise shown is the object plane 29, which is imaged into the image plane by the imaging optical unit 35. The plane 201 at which the deflection effect on the particle beam 5 can be located is at a distance 1 from the object plane 29, which is small compared to the distance of the object plane 29 from the image plane 7 along the optical axis 209. In particular, the distance 1 is less than 0.1 times the distance between the object plane 29 and the image plane 7 along the optical axis 209.

[0080] Reference below Figure 5 and Figure 6 Another embodiment of the deflector array 41 is described. In this case, Figure 5 shows a plan view of the deflector array 41, Figure 6 The deflector array 41 is shown along Figure 5 The section of line VV in .

[0081] The deflector array 41 comprises a first porous plate 56 having a plurality of openings 45, and a second porous plate 57 having a plurality of openings 45', through which the particle beams 5 pass. The two porous plates 56 and 57 are arranged one behind the other in the beam path, so that each particle beam 5 first passes through the openings 45 in the first porous plate 56 and then through the openings 45' in the second porous plate 57. The openings 45 and 45' in the two porous plates 56 and 57 can each have the same diameter. However, this is not necessarily the case.

[0082] The two perforated plates 56 and 57 are arranged relative to each other so that, seen in the beam direction, the center of the opening 45 through which a given particle beam passes in the first perforated plate 56 is laterally offset relative to the opening 45′ through which said particle beam passes in the second perforated plate 57. Figure 5 This is illustrated by the fact that the openings 45 in the first perforated plate 56 are fully visible and are shown as solid lines, whereas the openings 45' in the second perforated plate 57 are partially hidden and are shown with solid lines whenever they are visible and with dashed lines whenever they are hidden.

[0083] The controller 59 is configured to apply mutually different potentials to the first porous plate 56 and the second porous plate 57. An electrostatic field is thereby generated between the porous plates 56 and 57, which deflects the particle beam 5. The deflection angle can be set by the potential difference between the porous plates 56 and 57 determined by the controller 59.

[0084] The deflector array comprises a center 53 about which a second porous plate 57 rotates relative to the first porous plate, such as Figure 5 This rotation generates a lateral displacement in the circumferential direction around the center 53 between the openings 45 and 45' through which the particle beam 5 passes successively, wherein the lateral displacement increases in the circumferential direction as the distance between the respective openings 45 and 45' and the center 53 increases.

[0085] By arranging the deflector array 41 near the surface 29, which is imaged into the plane 7 at the surface of the object 9, the angles of incidence of the particle beam 5 on the plane 7 can be influenced. In particular, the angles of incidence can be set in such a way that they are approximately 90° for all particle beams.

[0086] Figure 1The particle beam system 1 shown in the figure comprises an irradiation system 3 in order to generate a particle beam 5 and to direct the particle beam into a plane 7 in which the surface of an object 9 is arranged. In addition, the particle beam system 1 comprises an imaging optical unit 11 in order to direct the electrons generated at the surface of the object 9 as a particle beam 15 onto a detector array 13. For this purpose, the beam path of the particle beam 5 and the beam path of the particle beam 15 are separated from each other by a beam switch 65. Between the beam switch 65 and the plane 7, the particle beams 5 and 15 travel through a common beam path, while their beam paths are in the plane 7. Figure 1 The beam switch 65 is provided by a substantially uniform magnetic field. Figure 1 Reference numeral 67 in denotes a region in which a uniform magnetic field is provided, through which the particle beam 5 passes and which is provided to compensate for imaging aberrations generated by the magnetic field of the beam switch 65 when imaging the plane 29 onto the plane 7 .

[0087] The imaging optical unit 11 includes an objective lens 37 and a plurality of lenses 69. Figure 1 It is schematically shown in Figure 2 These lenses are shown in more detail in . The imaging optical unit 11 images the plane 17 onto a plane 19 in which the detector elements of the detector array 13 are arranged in such a way that three intermediate images 71, 72 and 73 appear one after the other along the beam path of the particle beam 15. In addition, there is a crossing of the particle beam 15 in a plane 75 arranged on the beam path between the intermediate images 72 and 73. An aperture plate 77 is arranged in the plane 75, which has a cutout 79 for filtering out particles of the particle beam 15 that hit a detector element of the detector array 13, which detector element is different from the detector element(s) assigned to that position in the plane 7 from which the particles start.

[0088] As mentioned above, if the particle beam 15 starts non-orthogonally from the plane 7, ie at an angle different from 90°, the quality of the filtering is reduced. This can happen in practice, for example, if the objective 37 generates a focusing magnetic field that reaches as far as the plane 7.

[0089] To compensate for this, a deflector array 81 is arranged in the region of the intermediate image 72, said deflector array comprising an array of deflectors, wherein each deflector is traversed by a particle beam 15. The deflectors deflect the particle beam traversing them in such a way that the particle beam traverses the smallest possible area in the plane 75 and the opening 79 can be chosen to be small enough to achieve good filtering with a high throughput.

[0090] The deflector array 81 may have the same configuration as described above with respect to the deflector array 41. Figures 3 to 5 The structure described.

[0091] Figure 7 is used to generate Figure 1 2. The cross-sectional schematic diagram of an embodiment of a porous plate arrangement 27 for a particle beam 5 in a particle source 21. The porous plate arrangement 27 comprises a first porous plate 101 having a plurality of openings 103, through which the particle beam 5 passes. In this case, the porous plate 101 can be the first porous plate on the beam path downstream of the particle source 21, so that the porous plate 101 also absorbs those particles that do not contribute to the particle beam 5 in the particle beam 23 produced by the particle source 21. However, another porous plate can also be arranged upstream of the porous plate 101, and the other porous plate provides this function, so that the porous plate 101 does not substantially absorb the particles produced by the particle source 21. The single-hole plate 105 is arranged at a distance L1 from the porous plate 101. The single-hole plate 105 has an opening 107, through which all particle beams 5 pass.

[0092] Another single hole plate 109 is arranged at a distance L2 from the porous plate 101 and has an opening 111, and all particle beams 5 also pass through this opening. Opening 111 includes a diameter D2. Another single hole plate 113 is arranged at a distance L3 from the porous plate 101 and has an opening 115, and all particle beams 5 also pass through this opening. Opening 115 has a diameter D3. The controller 117 is configured to apply different potentials to the porous plate 101 and the single hole plates 105, 109 and 113. In this case, the single hole plate 113 can also be connected to a beam tube, for example, the beam tube can be at ground potential.

[0093] Due to the different potentials applied to the multi-hole plate 101 and the single-hole plates 105, 109 and 113, an inhomogeneous electric field is generated between these plates, such as Figure 7 As shown in the field lines 119.

[0094] The electric field extending to the porous plate 101 has the effect that the openings 103 in the porous plate 101 act as lenses on the particle beam 5 passing through the openings 103. This lens effect is caused by Figure 7 The ellipse 121 in FIG. 1 is represented by the ellipse 121 in FIG. Due to the inhomogeneity of the electric field, the central opening 103 in the array of openings 103 in the porous plate 101 provides the strongest lens effect, and this lens effect decreases with increasing distance from the center. This has the following effect: From the perspective of the particle source, the beam focus 31 (see Figure 1) is not located in a plane, but in a convex curved plane. The shape and size of the curvature of this plane are determined by the intensity and inhomogeneity of the electric field at the porous plate 101. Inhomogeneity is then determined substantially by the diameter D1 of the opening 107 in the single-hole plate 105 and the distance L1 between the porous plate 101 and the single-hole plate 105. Select these variables D1 and L1 so that the resulting shape of the curvature of the surface 29 where the beam focus 31 is arranged can compensate for the field curvature of the imaging optical unit 35, so that the focus of the particle beam 5 at the surface of the object 7 basically all appears in a place very close to the plane 7. In addition, the size of the curvature of the plane 29 is determined by the potential difference between the porous plate 101 and the single-hole plate 105.

[0095] The distance L2 between the single-hole plate 109 and the porous plate 101 is significantly greater than the distance L1 between the single-hole plate 105 and the porous plate 101. In particular, the distance L2 is more than twice, particularly more than five times, and particularly more than ten times the distance L1. The diameter D2 of the opening 111 in the single-hole plate 109 is also significantly greater than the diameter D1 of the opening 107 in the single-hole plate 105. For example, the diameter D2 is more than 1.5 times larger, particularly more than three times larger than the diameter D1. The distance L3 between the single-hole plate 113 and the porous plate 101 is also significantly greater than the distance L1 between the single-hole plate 105 and the porous plate 101. The distance L3 is also greater than the distance L2. The diameter D3 of the opening 115 of the single-hole plate 113 is also significantly greater than the diameter D1 of the opening 107 in the single-hole plate 105. The diameter D3 can be approximately equal to the diameter D2.

[0096] The inhomogeneous electric field formed in the beam path downstream of the single aperture plate 105 provides a lens effect on the entire particle beam 5, such as Figure 7 123 in FIG. The lens effect changes the divergence and / or convergence of the particle beams 5 relative to each other. The intensity of the effect of this lens 123 can be set by changing the voltage between the single hole plates 105, 109 and 113. The intensity change of this lens 123 causes a change in the distance between the beam foci 31 on the surface 29.

[0097] By means of the perforated plate arrangement 27, it is thus possible firstly to compensate for the field curvature of the imaging optical unit 35 and secondly to set the distance between the beam foci 31 in the plane 29. In this case, the controller 117 may have a first signal input 125, via which the desired magnitude of the field curvature compensation may be input to the controller 117, and the controller 117 may have a second signal input 127, via which the desired distance between the beam foci 31 in the surface 29 or the desired distance between the incident positions of the particle beam in the plane 7 may be input to the controller 117. Due to the described configuration of the perforated plate arrangement 27, the effect of the lens 121 may be adjusted in a manner largely separated from the effect of the lens 123. In the event of a change in the signal applied to the first signal input 125, the controller 117 may then change the voltage between the perforated plate 101 and the single-hole plate 105 in order to set the curvature of the surface 29. In case the control signal applied to the second signal input 127 is changed, the controller 117 can then drastically change the potential applied to the single aperture plate 109 in order to change the distance between the incidence positions of the particle beam on the surface of the object 9 .

[0098] According to an exemplary embodiment Figure 7 The parameters of the multi-hole plate arrangement 27 in are as follows;

[0099] Kinetic energy of the particle beam 5 before passing through the porous plate 101: 30 keV;

[0100] Distance between openings 103: 100 μm;

[0101] Diameter of opening 103: 30 μm;

[0102] Focal length of lens 121: 100 mm to 300 mm;

[0103] D1: 4mm; D2: 16mm; D3: 6.5mm; L1: 0.2mm; L2: 7.3mm; L3: 65mm, U1: 0; U2 500V; U3: 17.5kV; U4: 0;

[0104] Distance between the focal points in plane 29: 200 μm to 300 μm.

[0105] Figure 8 is used to generate Figure 1 Schematic illustration of a cross section of a further exemplary embodiment of a porous plate arrangement 27 of a particle beam 5 in FIG. Figure 8 The perforated plate arrangement 27 has the Figure 7In particular, a single-hole plate 105 having an opening 107 is arranged at a distance L1 from the porous plate 101, and the opening has a diameter D1. Similarly, a single-hole plate 113 having an opening 115 is arranged at a distance L3 from the porous plate 101, and the opening has a diameter D3. However, instead of Figure 7 A single hole plate 109 is provided, three single hole plates 1091, 1092 and 1093 having openings 1111, 1112 and 1113, each having a diameter D2, are provided, and the single hole plates are arranged at distances L21, L22 and L23 from the multi-hole plate 101, respectively.

[0106] L1 is again significantly smaller than L21 and L3, and D1 is significantly smaller than D2 and D3. The difference between L22 and L21 and between L23 and L22 may be, for example, slightly smaller than L21.

[0107] Fig. 9 is a schematic illustration of a cross section of another embodiment of a multi-beam particle source 21. The multi-beam particle source 21 comprises a plurality of particle emitters 131 arranged in a plane 135. A porous plate 137 is arranged at a distance from the plane 135. The porous plate 137 is at a positive potential relative to the particle emitters 131 so as to extract electrons from the particle emitters 131. The electrons are accelerated from the particle emitters 131 towards the porous plate 137 and pass through the porous plate, through the openings 139 in the porous plate 137 so as to shape a plurality of particle beams 5. The particle emitters 131 are arranged in a field generating arrangement 41. The field generating arrangement 41 is formed by a coil 141 through which a current is passed to generate a magnetic field, the field lines 143 of which pass substantially orthogonally through the plane 135. In the region of the particle emitters 131, the magnetic field is a substantially uniform magnetic field.

[0108] The particle beam 5 starts at the particle emitter 131, essentially parallel to the field lines 143 of the magnetic field, and is not yet deflected by the magnetic field. However, the particle beam 5 then passes through the magnetic field region where the field lines 143 diverge. There, the particle beam 5 is deflected by deflection angles that are oriented in a circumferential direction around the optical axis 209 of the imaging optical unit 35.

[0109] The plane 135 in which the particle emitters 131 are arranged is imaged into the image plane 7 by the imaging optical unit 35. The excitation of the coil 141 then makes it possible to set the angle at which the particle beam 5 is incident on the image plane. In particular, the incident telecentricity of the particle beam 5 in the circumferential direction around the optical axis 209 can thus be set and the telecentricity error generated at the object 17 by the magnetic field of the objective lens 37 can be compensated.

[0110] Fig.101 is a schematic illustration of another embodiment of a particle beam system 1, which includes an irradiation system 3 with a multi-beam particle source 21. The multi-beam particle source 21 includes a particle emitter 22 for generating a particle beam 23, which passes through a beam-forming lens 25 and then hits a porous plate 151 with openings, and the particles of the particle beam 23 pass through these openings so as to form a plurality of particle beams 5 downstream of the porous plate 151. Another porous plate 101 is arranged on the beam path downstream of the porous plate 151 and has openings, and the particle beam 5 also passes through these openings. One or more single-hole plates 153 are arranged on the beam path downstream of the other porous plate 101.

[0111] As above combined Figure 7 and Figure 8 As explained, the openings of the further perforated plate 101 act like a lens on the particle beam 5 passing through the lens, which also Fig.10 121 in order to focus the particle beam in the curved surface 155 at the position 31, which is also the object plane 29, which is imaged by the imaging optical unit 35 onto the image plane 7, in which the object 17 can be arranged.

[0112] A controller 117 is provided to set the potentials of the other multi-aperture plate 101 and the single-aperture plate 153 and the excitation of the condenser lens 25. Figure 7 and Figure 8 As with the controller of the illustrated embodiment, the controller 117 includes a signal input 125 at which a desired field curvature compensation magnitude may be input to the controller 117. Figure 7 and Figure 8 In the illustrated embodiment, the controller 117 is configured to change the potential of the additional porous plate 101 and the single-hole plate 153 in response to a change in the signal applied to the signal input 125 so as to set the refractive power of the lens 121 relative to a change in the curvature of the plane 29.

[0113] The controller 117 further comprises a signal input 127 by which a desired distance between the beam foci 31 in the plane 7 can be input to the controller 117 .

[0114] According to the signal input by signal input 127, controller 117 changes the excitation of condenser lens 25. With the change of the excitation of condenser lens 25, the divergence of particle beam 23 incident on porous plate 151 changes. Therefore, on the beam path downstream of porous plate 151, the divergence of particle beam 5 also changes. This in turn causes the change of the area in the cross section of the opening in other porous plate 101, wherein particle beam 5 passes through the opening. In particular, particle beam 5 does not pass through the opening centered, but passes at a distance from the center of the opening. Due to the change of the excitation of condenser lens 25, the distance from the center of the opening when particle beam 5 passes through the opening in other porous plate 101 is changed. If particle beam does not pass through the opening of other porous plate 101 centered, the lens effect of lens 121 on the light beam not only causes focusing but also causes deflection, so that particle beam 5 does not pass through lens 121 in a straight line, but is also deflected by the lens. The deflection of lens 121 on light beam 5 causes the position 31 of beam focusing in plane 29 to change. Thus, the distance between the beam foci 31 in plane 29 can be varied by varying the excitation of condenser lens 25. Since plane 29 is imaged onto plane 7, the distance between the beam foci in image plane 7 will also vary.

[0115] The present invention has been described above using the preferred embodiments. However, the present invention defined by the scope of the patent claims is not limited to the described embodiments and covers the scope given by the patent claims and their equivalents.

Claims

1. A particle beam system, comprising: a multi-beam particle source configured to generate a plurality of particle beams; an imaging optical unit configured to particle-optically image the object plane into an image plane and to direct the plurality of particle beams onto the image plane; as well as a first porous plate having a plurality of first openings and being configured to generate electric and / or magnetic deflection fields of adjustable strength in a region near the object plane, wherein the particle beams are deflected by the deflection fields during operation, the deflection angle being dependent on the strength of the deflection fields, wherein the distance between the object plane and a plane including the vertex of the deflection angle and parallel to the object plane is less than 0.1 times the distance between the object plane and the image plane, wherein the first porous plate comprises a deflector array having a plurality of deflectors arranged side by side with one another such that each opening of the porous plate comprises a deflector, wherein a set of particle beams passes through each of the deflectors during operation, wherein each of the deflectors comprises at least one pair of electrodes located opposite to each other, between which the particle beam passes through the deflector, and The particle beam system further includes a controller configured to apply mutually different adjustable potentials to electrodes in the pair of electrodes to adjust an angle at which the particle beam is incident on the image plane.

2. The particle beam system according to claim 1, wherein: The imaging optical unit comprises an objective lens which provides a focusing magnetic field having a magnetic field strength greater than 20 mT at the image plane.

3. The particle beam system according to claim 2, wherein: The magnetic field strength is greater than 50 mT.

4. The particle beam system according to claim 2, wherein: The magnetic field strength is greater than 150mT.

5. The particle beam system according to claim 2, wherein: The first porous plate is configured to generate an electric and / or magnetic deflection field such that the deflected particle beam is incident orthogonally on the image plane.

6. The particle beam system according to any one of claims 1 to 5, wherein: The multi-beam particle source comprises a plurality of particle emitters which are arranged side by side with each other near the object plane, and each particle emitter generates one particle beam or a plurality of particle beams among the plurality of particle beams, and The first porous plate comprises a magnetic coil configured to generate a magnetic field, the particle emitters are arranged in the magnetic field, and a field direction of the magnetic field in the object plane is oriented to be orthogonal to the object plane.

7. A particle beam system comprising: an irradiation system configured to direct a plurality of particle beams side by side with one another onto an object plane so that the particle beams irradiate a plurality of incident positions in the object plane; an imaging optical unit configured to direct the plurality of particle beams emitted from the incident positions onto a detector array and to image the object plane into an intermediate image plane arranged on a beam path between the object plane and the detector array; as well as a first porous plate having a plurality of first openings and being configured to generate electric and / or magnetic deflection fields of adjustable strength in a region near the intermediate image plane, wherein the particle beams are deflected by the deflection fields during operation, the deflection angle being dependent on the strength of the deflection fields, wherein the distance between the intermediate image plane and a plane including the vertex of the deflection angle and parallel to the intermediate image plane is less than 0.1 times the distance between the intermediate image plane and the detector array, wherein the first porous plate comprises a deflector array having a plurality of deflectors arranged side by side with one another such that each opening of the porous plate comprises a deflector, wherein a set of particle beams passes through each of the deflectors during operation, wherein each of the deflectors comprises at least one pair of electrodes located opposite to each other, between which the particle beam passes through the deflector, and The particle beam system further includes a controller configured to apply mutually different adjustable potentials to electrodes in the pair of electrodes to adjust an angle at which the particle beam is incident on the detector array.

8. The particle beam system according to claim 7, wherein: The imaging optical unit comprises an objective lens which provides a focusing magnetic field having a magnetic field strength greater than 20 mT at the object plane.

9. The particle beam system according to claim 8, wherein: The magnetic field strength is greater than 50 mT.

10. The particle beam system according to claim 8, wherein: The magnetic field strength is greater than 150mT.

11. The particle beam system according to any one of claims 7 to 10, wherein: The first porous plate is configured to generate an electric and / or magnetic deflection field such that the deflected particle beam is orthogonally incident on the detector array.

12. The particle beam system according to any one of claims 1 to 5 and 7 to 10, wherein: The first porous plate is configured such that for one of the particle beams, the following first condition holds: The edge of the deflection angle of the particle beam deflected by the first porous plate is located in a plane whose normal passing through the vertex of the deflection angle is at a distance from the optical axis of the imaging optical unit that is less than 0.99 times the distance between the vertex of the deflection angle and the main axis.

13. The particle beam system according to any one of claims 1 to 5 and 7 to 10, wherein: The first porous plate is configured such that for one of the particle beams, the following first condition holds: The edge of the deflection angle of the particle beam deflected by the first porous plate is located in a plane whose normal passing through the vertex of the deflection angle is at a distance from the optical axis of the imaging optical unit that is less than 0.95 times the distance between the vertex of the deflection angle and the main axis.

14. The particle beam system according to any one of claims 1 to 5 and 7 to 10, wherein: The first porous plate is configured such that for one of the particle beams, the following first condition holds: The edge of the deflection angle of the particle beam deflected by the first porous plate is located in a plane whose normal passing through the vertex of the deflection angle is at a distance from the optical axis of the imaging optical unit that is less than 0.90 times the distance between the vertex of the deflection angle and the main axis.

15. The particle beam system of claim 12, wherein: The first porous plate is configured such that the following second condition holds for one of the particle beams: The particle beam is deflected by the first porous plate at a deflection angle greater than 10 μrad.

16. The particle beam system of claim 15, wherein: The particle beam is deflected by the first porous plate at a deflection angle greater than 50 μrad.

17. The particle beam system of claim 15, wherein: The particle beam is deflected by the first porous plate at a deflection angle greater than 100 μrad.

18. The particle beam system of claim 15, wherein: The particle beam is deflected by the first porous plate at a deflection angle greater than 300 μrad.

19. The particle beam system of claim 15, wherein: The first condition and / or the second condition holds true for more than 10% of the particle beams.

20. The particle beam system of claim 15, wherein: The first condition and / or the second condition holds true for more than 20% of the particle beams.

21. The particle beam system of claim 15, wherein: The first condition and / or the second condition holds true for more than 30% of the particle beams.

22. The particle beam system of claim 15, wherein: The first condition and / or the second condition holds true for more than 40% of the particle beams.

23. The particle beam system according to any one of claims 1 to 5 and 7 to 10, wherein: The deflector array includes a center, and Therein, a connection line between the centers of two electrodes of a pair of electrodes of each deflector is oriented in a circumferential direction relative to the center of the deflector array.

24. The particle beam system according to any one of claims 1 to 5 and 7 to 10, wherein: Each of the deflectors comprises at least one first plate and one second plate, the plates being arranged one behind the other on the beam path, wherein the first plate has a first opening and the second plate has a second opening, through which the particle beam passes, wherein the center of the first opening is laterally offset relative to the center of the second opening, seen in the direction of the beam path, and The particle beam system further includes a controller configured to apply mutually different potentials to the first plate and the second plate.

25. The particle beam system of claim 24, wherein: The deflector array includes a center, and Wherein, viewed in the beam path direction, the center of the first opening is offset relative to the center of the second opening in a circumferential direction relative to the center of the deflector array.

26. The particle beam system of claim 24, wherein: A plurality of deflectors in the deflector array include a common first porous plate having the plurality of first openings and a common second porous plate having the plurality of second openings, wherein the group particle beams pass through one of the first openings and one of the second openings, respectively.

27. The particle beam system according to any one of claims 1 to 5 and 7 to 10, wherein: The set of particle beams includes a single particle beam.

28. The particle beam system according to any one of claims 1 to 5 and 7 to 10, wherein: The deflection fields are generated in such a way that for pairs of particle beams among the particle beams passing through the object plane or the intermediate image plane, the following relations hold: 0.9<r1 / r2*α2 / α1<1.1 in r1 represents the radial distance between the position where the first particle beam of the pair passes through the object plane or the intermediate image plane and the center of this plane, r2 represents the radial distance between the position where the second particle beam of the pair passes through the object plane or the intermediate image plane and the center of this plane, α1 represents the absolute value of the deflection angle of the first particle beam deflection, and α2 represents the absolute value of the deflection angle of the second particle beam deflection.

29. The particle beam system of claim 28, wherein: This relationship holds true for half of the particle beams in these paired particle beams.

30. The particle beam system of claim 28, wherein: This relationship holds true for three quarters of the particle beam pairs.

31. The particle beam system of claim 28, wherein: This relationship holds true for all of these paired particle beams.

32. The particle beam system of claim 28, wherein: The deflection fields are generated in such a way that the particles are deflected substantially in a circumferential direction about the center.

33. The particle beam system according to any one of claims 1 to 5 and 7 to 10, wherein: The multi-beam particle source includes a particle emitter for generating a particle beam, and a porous plate arranged on a beam path of the particle beam and having a plurality of openings through which particles of the particle beam pass, so that the plurality of particle beams are generated on the beam path downstream of the porous plate.

34. A particle beam system, comprising an illumination system, the illumination system being configured to direct a plurality of particle beams onto a sample plane so that the particle beams illuminate an incident position field at the sample plane, wherein: The irradiation system includes: a perforated plate which is arranged in the beam path of the particle beams and has a plurality of openings, wherein the particle beam passes through each of the openings, a first single-hole plate having an opening through which the plurality of particle beams pass, wherein the first single-hole plate is disposed at a first distance from the multi-hole plate; a second single-aperture plate having an opening through which the plurality of particle beams pass, wherein the second single-aperture plate is disposed at a second distance from the multi-aperture plate; and a voltage source configured to apply an adjustable first potential to the first single-well plate relative to the multi-well plate, and to apply an adjustable second potential to the second single-well plate relative to the multi-well plate; The first distance is less than 0.5 times the second distance.

35. The particle beam system of claim 34, wherein: The first distance is less than 0.2 times the second distance.

36. The particle beam system of claim 34, wherein: The first distance is less than 0.1 times the second distance.

37. The particle beam system of claim 34, wherein: Apart from the first single-hole plate and the second single-hole plate, no further single-hole plate is arranged at a distance from the multi-hole plate that is less than the second distance.

38. The particle beam system of claim 34, wherein: The opening in the first single hole plate has a first diameter, the opening in the second single hole plate has a second diameter, and wherein the second diameter is 1.5 times larger than the first diameter.

39. The particle beam system of claim 38, wherein: The second diameter is 3 times larger than the first diameter.

40. The particle beam system of any one of claims 34 to 39, wherein: The first single-hole plate is disposed between the multi-hole plate and the second single-hole plate.

41. The particle beam system of any one of claims 34 to 39, wherein: The multi-well plate is disposed between the first single-well plate and the second single-well plate.

42. The particle beam system according to any one of claims 34 to 39, further comprising at least one third single-hole plate having an opening through which the plurality of particle beams pass, wherein The third single-hole plate is arranged at a third distance from the multi-hole plate, wherein the third distance is greater than the second distance, wherein a distance between the second single-hole plate and the third single-hole plate is less than the third distance.

43. The particle beam system of any one of claims 34 to 39, further comprising a voltage source configured to apply an adjustable potential to the multi-well plate and the single-well plates.

44. The particle beam system of claim 43, wherein: The illumination system is configured to focus the particle beams on beam paths downstream of the porous plate and upstream of the object plane, respectively, wherein respective beam foci are arranged on a curved surface.

45. The particle beam system of claim 44, further comprising a controller configured to control the voltage source and receive a first signal representing a desired curvature of the surface, wherein: In the event that the first signal changes, the controller causes the voltage source to change the potential difference between the multiwell plate and the first single well plate to a greater extent than the potential difference between the multiwell plate and the second or third single well plate.

46. ​​The particle beam system of claim 44, further comprising a controller configured to control the voltage source and receive a second signal representing a desired distance between the incident locations of the particle beams in the object plane, wherein In the event that the second signal changes, the controller causes the voltage source to change the potential difference between the multiwell plate and the first single well plate to a lesser extent than the potential difference between the multiwell plate and the second or third single well plate.

47. A particle beam system, comprising an irradiation system, the irradiation system being configured to direct a plurality of particle beams onto an object plane so that the particle beams irradiate an incident position field at the object plane, wherein: The irradiation system includes: a particle emitter configured to generate a particle beam; at least one condenser lens through which the particle beam passes; a first porous plate, which is arranged on the beam path of the particle beam downstream of the condenser lens and has a plurality of openings through which particles of the particle beam pass, so that a plurality of particle beams are formed on the beam path downstream of the first porous plate; a second porous plate disposed in the beam path downstream of the first porous plate and having a plurality of openings, wherein each of the openings is penetrated by a particle beam of the plurality of particle beams; and A controller configured to: - energizing the at least one condenser lens so that the at least one condenser lens provides an adjustable refractive power for the particle beam; - receiving a first signal representative of an expected distance between the incidence positions of the particle beams in the object plane, and - changing the optical power of the at least one focusing lens in the event of a change in the first signal.

48. The particle beam system of claim 47, wherein: The irradiation system is configured to focus the particle beams on beam paths downstream of the second porous plate and upstream of the sample plane, respectively, wherein the respective beam foci are arranged on a curved surface, wherein the particle beam system further comprises a single-hole plate, which is arranged on the beam path upstream or downstream of the second porous plate and has an opening through which the plurality of particle beams pass, wherein the controller is configured to - provide an adjustable potential difference between the single-hole plate and the second porous plate, - receiving a second signal representative of a desired curvature of the surface, and - changing the potential difference between the single-well plate and the second multi-well plate when the second signal changes.

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