Multi-beam particle beam system with electrostatic enhancement lens, method of operating multi-beam particle beam system and associated computer program product

Abstract

The invention relates to a multi-particle beam system (1) with better resolution and faster recording speed. To this end, an electrostatic enhancement lens (112) is disposed in an upper focal plane where the objective lens (102) intersects with the primary particle beam. The electrostatic enhancement lens (112) is used in a targeted manner to significantly increase the kinetic energy of the primary beam (3) in the intersection region (108), which is a cause of what reduced coulomb interaction between charged particles.

Description

Technical Field

[0001] This invention relates to a multi-beam particle system that operates using multiple individually charged particle beams. Specifically, the invention relates to a multi-beam particle system with an electrostatic intensifying lens, a method for operating the multi-beam particle system, and an associated computer program product. Background Technology

[0002] As microstructures such as semiconductor components continue to shrink and become increasingly complex, there is a need to further develop and optimize planar fabrication techniques and inspection systems for generating and inspecting these small-sized microstructures. For example, the development and fabrication of semiconductor components requires monitoring the design of test wafers, and planar fabrication techniques necessitate process optimization to achieve high-volume, reliable production. Furthermore, there is a growing demand for the analysis of semiconductor wafers used in reverse engineering and for the customized, individual construction of semiconductor components. Therefore, there is a need for an inspection tool capable of inspecting microstructures on wafers with high precision and high throughput.

[0003] Typical silicon wafers used to fabricate semiconductor components can be up to 300 mm in diameter. Each wafer is subdivided into 30 to 60 repeating regions (“bare dies”), with dimensions up to 800 mm. 2 Semiconductor devices comprise multiple semiconductor structures, which are formed in layers on the surface of a wafer using planar integration technology. Due to the fabrication process, semiconductor wafers typically have planar surfaces. In this case, the structural dimensions of the integrated semiconductor structures range from a few micrometers to the critical size (CD) of a few nanometers, and are expected to become even smaller in the near future; future structural dimensions, or critical sizes (CD), are anticipated to conform to the International Technology Roadmap for Semiconductors (ITRS) process nodes of 3 nm, 2 nm, or even smaller. With these small structural dimensions, defects on the order of the critical size must be rapidly identified over very large areas. For some applications, the specifications for the measurement accuracy provided by the inspection equipment are even higher, for example, improved by two or an order of magnitude. For instance, the width of semiconductor features must be measured with an accuracy better than 1 nm, such as 0.3 nm or even smaller, and the relative positions of semiconductor structures must be determined with an overlay accuracy better than 1 nm, such as 0.3 nm or even smaller.

[0004] Multi-beam scanning electron microscopy (MSEM) is a relatively recent development in the field of charged particle inspection systems or particle microscopy. For example, US 7 244 949 B2 and US 2019 / 0355544 A1 disclose a multi-beam scanning electron microscope. In the case of multi-beam electron microscopy or MSEM, multiple individual electron beams are used to simultaneously irradiate the sample, these beams being configured in a field or grating. For example, 4 to 10,000 individual electron beams can be provided as a single radiation, with each individual electron beam spaced 1 to 200 micrometers apart from adjacent individual electron beams. For example, an MSEM may have approximately 100 separate individual electron beams (“beamlets”), configured, for example, in a hexagonal grating, with the individual electron beams separated by a spacing of approximately 10 µm.

[0005] An electron beam bundle; or more generally, an individual charged particle beam, is formed by guiding a primary charged particle beam into a porous configuration containing at least one porous plate with multiple openings. Some charged particles of the primary charged particle beam strike the porous plate and are absorbed there, while another portion of the primary charged particle beam passes through the openings in the porous plate, thereby forming a first separate charged particle beam in the beam path downstream of each opening, the profile of which is defined by the profile of the opening.

[0006] Multiple individual charged particle beams (primary beams) are focused onto the surface of the sample to be inspected by a common objective lens. For example, the sample may be a semiconductor wafer fixed to a wafer holder mounted on a movable sample platform. When the wafer surface is irradiated by the first individual charged particle beam, interaction products (e.g., secondary electrons or backscattered electrons) are emitted from the object surface. Their origin corresponds to the locations on the sample / object where each of the multiple primary individual particle beams is focused. The number and energy of the interaction products depend on the material composition and the wafer surface morphology. The interaction products form multiple secondary individual particle beams (secondary beams), which are collected by the common objective lens and, after passing through the projection imaging system of the multi-beam inspection system, are incident on a detector configured on the detection plane. The detector contains multiple detection regions, each of which may contain multiple detection pixels, and the detector acquires the intensity distribution of each of the secondary individual particle beams. In this process, an image field of, for example, 100 μm × 100 μm is obtained.

[0007] State-of-the-art multi-beam electron microscopes incorporate a series of electrostatic and magnetic elements. At least some of these elements are adjustable to tailor the focal positions and astigmatism of the multiple individual charged particle beams. State-of-the-art multi-beam systems with charged particles also include at least one intersecting plane of primary or secondary individual charged particle beams. Furthermore, the state-of-the-art system includes a detection system to facilitate adjustment. State-of-the-art multi-beam particle microscopes include at least one collective deflection scanner for collectively scanning an area of ​​the sample surface by multiple individual primary particle beams to obtain an image field of the sample surface. In this configuration, the primary individual particle beams systematically scan the sample surface, producing an electron microscope image of the sample in a manner consistent with scanning electron microscopy.

[0008] A so-called beam splitter (or alternatively, a beam splitter or beam separator) is used to separate the particle optical beam paths of the primary beam from those of the secondary beam. In this case, the separation is implemented by a special configuration of magnetic and / or electrostatic fields, such as through a Wien filter.

[0009] Typically, resolution and scan speed are the two most important characteristics of particle microscopes, or more generally, multi-beam particle systems. This is especially true for particle microscopes used in the semiconductor industry. Essentially, scan speed is a function of beam current. Using high beam current also allows for high scan speeds, enabling faster image generation.

[0010] Unfortunately, higher beam currents generate more Coulomb interactions between charged particles or particle beams. These Coulomb interactions are sources or causes of aberrations. Therefore, higher beam currents reduce the resolution of particle microscopy.

[0011] In multi-beam particle systems, the two characteristics of resolution and scanning speed are at least partially decoupled from each other. Specifically, this is because the entire beam current is divided into multiple spatially separated individual charged particle beams. Therefore, compared to single-beam particle systems, the resolution is less dependent on the total beam current in multi-beam particle systems due to systematic reasons.

[0012] However, in the case of multi-beam particle systems operating with a single column, it is also impossible to achieve spatial separation of individual particle beams along the entire illumination path. Instead, the laws of optics assume that a single path contains at least one intersecting plane or region where individual charged particle beams intersect or penetrate each other. Therefore, more Coulomb interactions occur in this intersecting region (also known as the pupil plane), which in turn promotes aberrations, negatively impacting the resolution of the multi-beam particle system. Thus, even in multi-beam particle systems, the total beam current cannot be simply increased further as needed; more precisely, it cannot be achieved by increasing the current of a single beam or by increasing the number of individual particle beams.

[0013] Essentially, the strength of the Coulomb interaction is also known to depend on the potential or kinetic energy of the charged particles. Higher kinetic energy reduces the generated Coulomb interaction. Therefore, state-of-the-art multi-beam particle systems operate at high potentials and with high kinetic energies of the particles within the column. For this purpose, a high voltage is applied to the particle source or a high voltage potential is provided to the particle source; essentially, the same applies to the sample platform or sample. For example, it can be operated at high voltages of approximately (+ / -)25 kV, (+ / -)28 kV, or (+ / -)30 kV in each case. The charged particles or particle beam are strongly accelerated in the particle source region and then move through essentially the entire column at very high speeds, only decelerating again before reaching the sample. Therefore, theoretically, one option is to further increase (given the absolute value) the high voltage applied to the particle source and the sample. However, in practice, this would lead to difficulties, especially in the sample or sample platform region. Even if increasing the high voltage applied to the sample platform (or simply the platform) and thus to the sample were feasible, there would be significant technical difficulties.

[0014] DE 10 2021 105 201 A1 discloses a multi-particle-beam microscope with a fast autofocus correction lens system having two-part autofocus correction lenses or a system with at least two fast autofocus correction lenses.

[0015] In Nuclear Instruments and Methods in Physics Research Section A 363 (1995), pages 31-42, S. Beck et al.'s article, "Low voltage probe forming columns for electrons," reveals a fundamentally known relationship between providing high beam energy and reducing electron-electron interactions within individual beams. The sample being examined was not at a high voltage potential. Summary of the Invention

[0016] The object of this invention is to provide a multi-beam particle beam system with improved resolution without reducing scan speed. In particular, the object of this invention is to further reduce aberrations caused by Coulomb interactions in the primary path of a single-column operated multi-beam particle beam system. Furthermore, from a technical point of view, this reduction should be readily implemented.

[0017] Another object of the present invention is to modify the numerical aperture in the object plane during operation of a multi-beam particle system. The numerical aperture depends on the total beam current and the landing energy. Modification of one of these quantities also leads to modification of the optimal numerical aperture for optimal resolution; therefore, it is advantageous to be able to adapt or adjust the numerical aperture.

[0018] Another objective of this invention is to modify the working distance or the position of the object plane relative to the objective lens, specifically without altering the magnification or telecentrism of the first particle beam incident on the object plane.

[0019] The stated objective / objectives are achieved by the subject matter of the independent claim. Advantageous embodiments of the invention will be apparent from the dependent claims.

[0020] This patent application claims priority to German patent application No. 10 2023 119 451.8, filed on July 24, 2023, the disclosure of which is incorporated herein by reference in its entirety.

[0021] The fundamental concept of this invention is that the kinetic energy of the first charged particle beam does not increase along the entire illumination column; instead, the kinetic energy of the first charged particle beam increases only in segments, more precisely, intentionally only at the locations with the most critical Coulomb interactions, i.e., in the cross regions. This solution significantly reduces Coulomb interaction-induced aberrations while avoiding problems that occur when even higher voltages (in absolute terms) can be applied to any type of sample platform / sample. To increase the segmented kinetic energy, electrostatic enhancement lenses are implemented; more precisely, the implementation does not require highly complex modifications to the particle optical imaging parameters, but instead provides one or more additional degrees of freedom for setting up a multi-beam particle system.

[0022] According to a first aspect of the present invention, the present invention relates to a multi-beam particle system comprising the following features:

[0023] A particle source, used to emit beams of charged particles;

[0024] A porous configuration comprising at least one porous plate having multiple channel openings, the porous configuration being configured to generate a first field from the charged particle beam of a plurality of first separately charged particle beams;

[0025] A first particle optical unit having a first particle optical beam path is configured to image the generated first separate particle beam onto the sample surface in the object plane, such that the first separate particle beam is incident on the sample surface at the incident position where the second field is formed.

[0026] A magnetic and / or electrostatic objective lens through which the first individual particle beam passes;

[0027] A sample platform is used to configure samples, with the sample surface located within the object plane.

[0028] An electrostatic intensifying lens, wherein the first particle optical beam path includes the intersection region of the first individual charged particle beam, the electrostatic intensifying lens is disposed in the region of the upper focal plane of the objective lens, and wherein the electrostatic intensifying lens is disposed in the region of the intersection region;

[0029] Voltage supply unit; and

[0030] The controller is used to control this multi-beam particle system.

[0031] The controller is configured to provide an enhanced high voltage VB at the electrostatic enhancement lens via the voltage supply unit, so that the first separately charged particle beam passes through the segment of the cross region with significantly increased kinetic energy, thereby reducing aberrations caused by Coulomb interactions between individual particle beams in the cross region.

[0032] The first individual charged particle beam can be, for example, electrons, positrons, muons, or ions or other charged particles. It is advantageous if the number of particles in the first individual particle beam is 3n(n-1)+1, where n is any natural number. The first individual particle beam can then be configured in a hexagonal field. However, the first individual particle beam may also have other configurations. The second individual particle beam can be backscattered electrons or secondary electrons. In this case, for analytical purposes, low-energy secondary electrons are therefore preferred for generating the image. However, mirror ions / mirror electrons can also be used as the second individual particle beam, i.e., the first individual particle beam undergoes inversion directly upstream of the object or at the object.

[0033] The sample can be of any type. Within the scope of this patent application, the term "sample" is generally used to refer to a substrate to be inspected or processed. Therefore, the term "sample" should be interpreted broadly. For example, examples of samples may be wafers, photomasks, or mask blanks.

[0034] The voltage providing unit according to the invention can be implemented as one or more components. In particular, it can be a modular design, for example having a module for providing high voltage and a module for providing low voltage. In this patent application, the terms "high voltage" and "low voltage" are used in the conventional sense in electrical engineering: in DC voltage operation, a voltage V > 1500 V is referred to as "high voltage." A voltage V ≤ 1500 V is referred to as "low voltage." The low voltage provided at the porous configuration according to a preferred embodiment of the invention is preferably an ultra-low voltage, the following applicable to ultra-low voltage in DC voltage operation: V ≤ 120 V. It can also be a ground potential.

[0035] According to the invention, an electrostatic boosting lens is disposed in the first particle optical beam path in the crossing region of the first individual charged particle beam. Ideally, the crossing region would be a crossing plane; however, this is not the case in reality, hence the reference to the crossing region. The electrostatic boosting lens is disposed in the region of this crossing region. Therefore, it acts on the first individual charged particle beam in the region of the crossing region. This effect is relatively abrupt, and this is implied by the term "booster." The key point is that the electrostatic boosting lens significantly increases the kinetic energy of the first individual particle beam in a relatively short section of the first particle optical beam path, so that the first individual particle beam passes through the crossing region with significantly increased kinetic energy. As a result, aberrations are significantly reduced due to the Coulomb interaction of the first individual particle beam in the crossing region. Furthermore, this increased kinetic energy exists only in the section; that is, for other sections of the particle optical beam path to the objective or sample, the electrostatic boosting lens substantially does not increase the kinetic energy of the individual charged particle beam; instead, after passing through the crossing region, the significantly increased kinetic energy is at least significantly reduced again. Therefore, the electrostatic enhancement lens significantly increases the kinetic energy of the first charged particle beam only in one section.

[0036] In the particle optical beam path between the particle source and the sample, the first individual particle beam has maximum kinetic energy in the intensifying lens region, and therefore in the intersection region, according to a preferred embodiment of the invention, the maximum potential growth ΔVB brought about by the intensifying lens, in absolute terms, is subject to the following relationship: ΔVB ≥ 10 kV, particularly ΔVB ≥ 15 kV. This maximum potential growth ΔVB is very high compared to the typical total potential change in the particle optical beam path. For example, the potential growth ΔVB brought about by the electrostatic intensifying lens may be ≥ 30%, ≥ 40%, or ≥ 50% of the potential difference that the charged particle (preferably electron) has experienced along its path from the particle source to the inlet of the intensifying lens. For example, a negative potential of -30 kV or a negative high voltage can be applied to the particle source. For example, an electron entering the intensifying lens is approximately at ground potential and has kinetic energy of 30 kV. Then, by passing through the intensifying lens, its kinetic energy can be further increased by ≥ 10 kV or ≥ 15 kV, corresponding to an increase of ≥ 1 / 3 or ≥ 50% of kinetic energy.

[0037] According to a preferred embodiment of the invention, the controller is configured to provide a first high voltage V1 at the particle source via a voltage providing unit. Furthermore, the controller is configured to provide at most a low voltage Vm at the porous configuration via the voltage providing unit, and the controller is configured to provide a second high voltage V2 at the sample platform and thus at the sample via the voltage providing unit.

[0038] According to a preferred embodiment of the invention, the first high voltage V1 and the second high voltage V2 have the same sign. Furthermore, in this variant of the embodiment, the following relationship applies, in absolute values, to the first high voltage V1 at the particle source: 20 kV ≤ V1 ≤ 40 kV, particularly 25 kV ≤ V1 ≤ 35 kV. Additionally, in absolute values, the following relationship applies to the second high voltage V2 at the sample platform: 20 kV ≤ V2 ≤ 40 kV, preferably 25 kV ≤ V2 ≤ 35 kV. Furthermore, in absolute values, the following relationship applies to the low voltage Vm at the porous configuration: 0 V ≤ Vm ≤ 100 V, preferably Vm = 0 V or ground potential. The fact that the first high voltage V1 and the second high voltage V2 have the same sign can be explained by the fact that the first charged particle beam is initially accelerated but then significantly decelerated again before reaching the sample. Typical landing energies incident on the sample are several hundred eV, such as 900 eV, 1.2 keV, or 1.5 keV. The high voltages V1 and V2 specified above, and the low voltage Vm or ground potential at the porous configuration, are also applied to the multi-beam particle system in this manner. A characteristic now within the scope of this invention is that these values ​​do not need to be changed. For example, this prevents problems that arise when a larger high voltage is applied to the sample platform. Maintaining the porous configuration, or so-called micro-optical unit, at a ground potential is also highly advantageous. This avoids problems, particularly in electronics and their control. However, electrostatic enhancement lenses can be used to make the first charged particle beam faster in the crossover region to reduce Coulomb interactions. Therefore, using enhancement lenses is a very elegant solution compared to solutions that provide higher voltages at both the particle source and the sample platform.

[0039] According to a preferred embodiment of the invention, the enhanced high voltage VB has a different sign than the first and second high voltages, wherein, in absolute terms, the following relationship applies to the enhanced high voltage VB at the electrostatic enhancement lens: VB ≥ 10 kV, particularly VB ≥ 15 kV. Therefore, if the particle source and sample platform are at a negative high voltage potential, then a positive high voltage potential is applied to the electrostatic enhancement lens according to this embodiment of the invention. This variant further embodies the aforementioned fundamental advantages of the configuration of the electrostatic enhancement lens.

[0040] According to another preferred embodiment of the invention, the following relationship applies to the length LB of the electrostatic intensifying lens along the particle optical axis Z: 2 mm ≤ LB ≤ 10 mm. Therefore, the electrostatic intensifying lens, or its lens field, has only a very small range along the particle optical axis Z, meaning that the segmented increase and deceleration of the kinetic energy of the first charged particle beam recurs over a very short distance. The length LB of the electrostatic intensifying lens is measured along the effectiveness of the lens and essentially corresponds to the path between the electrodes or counter-electrodes of the lens. According to another preferred embodiment of the invention, the following relationship applies to the length LBm of the center electrode of the electrostatic intensifying lens: 1.5 mm ≤ LBm ≤ 4.5 mm.

[0041] From a functional perspective, the electrostatic enhancement lens is essentially implemented as a variant of the ensemble lens according to a preferred embodiment of the invention. A characteristic of the ensemble lens is that charged particles have the same kinetic energy when entering and leaving it. Acceleration occurs only within the ensemble lens. This applies, at least in principle, to the electrostatic enhancement lens, thus allowing for a segmented, significant increase in kinetic energy and its return to its original position in the cross-region. This ensures the gain function. However, the counter-electrodes of the ensemble lens do not need to have exactly the same potential. This provides an advantage in correcting particle optical imaging parameters. Details of this will be discussed below.

[0042] According to a preferred embodiment of the invention, the lensing effect of the electrostatic enhancement lens is achieved at least in part by an offset voltage at the multipole electrode. This offset voltage at the multipole electrode (e.g., a quadrupole, octupole, or dodecupole electrode) also allows for setting the lensing effect of the multipole electrode. Preferably, the offset voltage is applied in this case to achieve one or more counter-electrodes of one or more multipole electrodes. However, a bias voltage can also be applied to the multipole electrode to achieve the center electrode of a single lens. These variations of the embodiment allow multipole electrodes already configured in the crossover region to be used in the design of the electrostatic enhancement lens in any case. For example, a collective scanning deflector can be provided in the beam crossover region or crossover region, and it may include a corresponding multipole electrode for the collective deflection of a first separate particle beam.

[0043] According to a preferred embodiment of the invention, a multi-beam particle system includes a beam tube configuration in which at least a first separate particle beam is guided in at least segmental manner, and wherein the beam tube configuration includes a beam tube extension extending into an objective lens. In this case, an electrostatic intensifying lens is disposed within the beam tube extension. In this embodiment variant of the invention, the electrostatic intensifying lens may be implemented as, for example, a single lens having a first electrode, a second (center) electrode, and a third electrode. Hereinafter, the beam tube extension is preferably substantially at ground potential.

[0044] According to an alternative embodiment of the invention, the multi-beam particle system includes a beam tube configuration in which at least a first separate particle beam is guided in at least segmented manner. Hereinafter, the beam tube configuration includes a beam tube interruption in a region of the intersection area, and the beam tube configuration is divided into a first beam tube segment and a second beam tube segment by the beam tube interruption. According to this embodiment, a first upper electrode of an electrostatic enhancement lens can then be formed through the first beam tube segment, to which only a low voltage VT1 is applied. Furthermore, a second center electrode of the electrostatic enhancement lens can be configured within the beam tube interruption, where an enhanced high voltage VB is provided. Additionally, a third lower electrode of an electrodynamic enhancement lens can be formed through the second beam tube segment, to which only a low voltage VT2 is applied. In this case, the low voltages VT1 and VT2 may be the same, but they may also be different from each other. From a functional point of view, according to this embodiment of the invention, the electrostatic enhancement lens can again be very easily implemented essentially as an ensemble lens. From a construction point of view, this electrostatic enhancement lens can also be very easily manufactured.

[0045] According to a preferred embodiment of the invention, a multi-beam particle system includes a collective scanning deflector having an upper deflection unit located in an upper crossover region and a lower deflection unit located in a lower crossover region. The crossover plane (i.e., the ideal plane for beam crossover) is located between the upper and lower crossover regions. In this variant of the invention, the center electrode of the electrostatic enhancement lens is now disposed between the upper and lower deflection units. With its center electrode, the electrostatic enhancement lens is thus located at the regional center of the crossover region or horizontally with the theoretical crossover plane. Therefore, the electrostatic enhancement lens has a highly targeted effect in the crossover regions of individual particle beams. A corresponding reverse potential of the center electrode in the form of an offset voltage is applied to both the upper and lower deflection units.

[0046] Placing an electrostatic intensifier lens in the cross region, or as flush as possible with the cross line, has further advantages or important results: the fundamental principle of multi-beam particle systems is that particle optical imaging parameters cannot be set independently of each other. Modifying one parameter usually requires adjusting another imaging parameter. However, in the cross region of the first individual particle beam, the particle optical imaging parameters are at least largely decoupled from each other. The electrostatic intensifier lens essentially only affects the alpha beam or axial beam and thus the focusing of the first individual particle beam, while the gamma beam or field beam passes through the system's axis of symmetry and thus remains essentially unaffected by the electrostatic intensifier lens. Therefore, providing an electrostatic intensifier lens in the cross region has a small impact on the imaging characteristics of the multi-beam particle system and does not cause complete misalignment of the entire system. Rather, when the first individual particle beam leaves the electrostatic intensifier lens, the electrostatic intensifier lens substantially causes a slight change in the focusing of the first individual particle beam. This modified focus position can be corrected or set relatively easily.

[0047] According to embodiments of the present invention, it is now even possible that a multi-beam particle system can not only be designed once for a specific enhanced high voltage or enhanced voltage VB; but also, the enhanced voltage can be changed and used to set the modified numerical aperture NA of the first individual particle beam when it is incident on the object plane.

[0048] According to a preferred embodiment of the invention, the multi-beam particle system further includes a first setting member, wherein the controller is configured to control the first setting member to modify the enhanced high voltage VB applied to the electrostatic intensifying lens. This, in turn, modifies the working distance WD of the first separate particle beam and / or the numerical aperture NA of the first separate particle beam incident on the object plane.

[0049] According to another preferred embodiment of the invention, the multi-beam particle system further includes a second setting member, different from the first setting member, the controller being configured to control the second setting member such that the modified working distance WD of the first separate particle beam is corrected and / or the modified numerical aperture NA of the first separate particle beam when incident on the object plane is corrected. Thus, the second setting member allows the particle optical properties to remain constant (otherwise, the particle optical properties would change due to the modified setting of the electrostatic intensifying lens). However, such correction is naturally redundant if the modified setting of the electrostatic intensifying lens is intentionally used to modify the particle optical parameters. The electrostatic intensifying lens then represents an additional degree of freedom in the adjustability of the particle optical imaging parameters. In particular, it can be used to purposefully set the numerical aperture NA, thereby optimizing the resolution. For details regarding the degrees of freedom and their use when specifically setting the particle optical imaging parameters and numerical aperture, see, for example, the description in International Patent Application WO2021 / 018332 A1, the disclosure of which is incorporated herein by reference in its entirety.

[0050] The second setting component (different from the first setting component) can be designed in different ways. It can be implemented as one part or multiple parts. A separate second setting component can be provided for a multi-beam particle system; however, particle optics elements that appropriately control the multi-beam particle system, which in any case already exist, can also be used as the second setting component.

[0051] According to a preferred embodiment of the invention, the second setting member is configured to cause a modification excitation of the objective lens and / or field lens. If the path of the first particle optical beam is considered to be from the intermediate image plane to the object plane, then the object plane substantially corresponds to a 4f system. For example, two focal lengths f1 can be provided here by the field lens, while two other focal lengths f2 can be provided by the objective lens of the multi-beam particle system. The electrostatic intensifying lens is located in the intersection region, resulting in it being substantially flush with the so-called pupil plane. As long as the objective focal length remains unchanged, the imaging characteristics of the so-called 4f system can be preserved while the focal length of the field lens is modified. In this case, the entire system can remain telecentric; the change in imaging scale is small and tolerable. Furthermore, the pupil plane remains substantially stationary and the position of the electrostatic intensifying lens remains within the intersection region. Specifically, the objective lens and field lens can be magnetic lenses, and in each case, the change in their excitation can be obtained by modifying the associated lens current.

[0052] In principle, the refractive power of an objective lens can also be changed by means other than altering the excitation of the objective lens. In principle, this can be achieved by changing the velocity of charged particles in the first particle beam within the objective lens's magnetic field, thereby changing the objective lens's refractive power.

[0053] According to a preferred embodiment of the invention, the second setting member is configured to implement modified control of the collective scanning deflector. A slightly modified offset potential can be applied to the upper and / or lower deflectors of the collective scanning deflector; in the case of the modified offset potential, this results in a corresponding lensing effect and velocity change, which in turn alters the refractive index of the objective lens for these individual particle beams. In this case, the bias voltage differs from the voltage applied to the beam tube.

[0054] According to another preferred embodiment of the invention, the second setting member is configured to apply a correction voltage VT2 to the second beam segment. This also results in altered lensing effects and the rate of change within the objective lens magnetic field.

[0055] According to another preferred embodiment of the invention, the second setting member includes an electrostatic correction element disposed in the magnetic field of the objective lens. For example, this could be an autofocus correction lens and / or a multipole corrector.

[0056] According to another embodiment of the invention, the second setting member can be configured to adjust only the focal length of the field lens without modifying the focal length of the objective lens. This modifies the original telecentric system to a non-telecentric system relative to the aforementioned 4f system. Therefore, it is a setting or correction option for adjusting the input telecentricity of individual particle beams when entering a 4f system.

[0057] According to a preferred embodiment of the invention, the multi-beam particle system further includes an intermediate image plane and a telecentric correction member, particularly an additional field lens in the path of the first particle optical beam, wherein the telecentric correction member is disposed between the multi-beam generator and the intermediate image plane. In this case, the controller is configured to control the telecentric correction member, particularly the additional field lens, such that the input telecentricity of the first particle beam varies in the intermediate image plane.

[0058] The extraction field between the objective lens and the sample can remain unchanged in both cases (by modifying both the objective lens focal length and the field lens focal length, or by modifying only the field lens focal length without modifying the objective lens focal length).

[0059] According to a preferred embodiment of the invention, the multi-beam particle system is configured such that the first separate particle beam is incident distally on the object plane. This is particularly advantageous for semiconductor samples with an HV structure; however, it may also be advantageous for other samples.

[0060] According to a preferred embodiment of the present invention, the multi-beam particle system further comprises:

[0061] The detection system has multiple detection zones that form a third field;

[0062] A second particle optical unit having a second particle optical beam path is configured to image a second particle beam (ejected from the incident position in the second field) onto a third field of the detection area of ​​the inspection system.

[0063] A beam splitter is configured in the first particle optical beam path between the multi-aperture device and the objective lens, and in the second particle optical beam path between the objective lens and the detection system.

[0064] The second separate particle beam also passes through the objective lens.

[0065] According to a preferred embodiment of the invention, the multi-beam particle system is an inspection system, particularly a multi-beam particle microscope. According to an alternative embodiment of the invention, the multi-beam particle system is a photolithography system. For example, the photolithography system can be used to generate photomasks or wafers via direct-write lithography. However, the multi-beam particle system according to the invention can also be of other types.

[0066] Provided that no technical contradictions arise as a result, all or part of the above embodiments of the present invention according to the first aspect can be combined with each other.

[0067] According to a second aspect of the invention, the invention relates to a method for operating a multi-beam particle system, particularly a multi-beam particle system as described above in several embodiment variations. In this case, the method comprises the following steps:

[0068] (a) Provides a multi-beam particle system having a first crossover region of charged particle beams in the illumination beam path in the upper focal plane of the objective lens; and

[0069] (b) The kinetic energy of the first separate particle beam in the cross region is significantly increased section-wise to significantly reduce the Coulomb interaction between the first separate charged particle beams. In particular, this can be achieved by implementing an electrostatic enhancement lens in the cross region, as described in several embodiment variations already described in the first aspect of the invention.

[0070] According to a preferred embodiment of the present invention, the method further includes the following steps:

[0071] (c) Modifying the maximum kinetic energy of the first individual particle beam in the intersection region, thereby modifying at least one imaging parameter of the multi-beam particle system when the first individual particle beam is incident on the object plane; and

[0072] (d) Correct at least one modified imaging parameter. For example, this imaging parameter could be the modified working distance WD or numerical aperture NA when the first individual particle beam is incident on the object plane. Alternatively, particle optics parameters such as telecentricity or magnification can be set or adjusted.

[0073] Furthermore, all that has been explained in the context of the first aspect of the invention also applies to the entirety of the second aspect of the invention. In particular, this also relates to definitions and advantageous embodiments.

[0074] According to a third aspect of the invention, the invention relates to a computer program product having program code for performing the methods described above in the context of the second aspect of the invention. In this case, the program code can be written in any desired programming language. The program code can be implemented in one or more parts. In particular, it is advantageous to provide separate program code concerning the control of the electrostatic enhancement lens. However, this is not mandatory. The program code can also adopt different structures. Attached Figure Description

[0075] The invention will now be better understood with reference to the accompanying drawings. In the drawings:

[0076] Figure 1 An example of using a multi-beam particle microscope schematically illustrates a multi-beam particle system;

[0077] Figure 2 schematically shown Figure 1 Details of the illumination column of a multi-beam particle system and a schematic diagram of the kinetic energy of a primary beam as it passes through the illumination column;

[0078] Figure 3 schematically shown Figure 1 Image sensors for multi-beam particle systems;

[0079] Figure 4 The diagram schematically illustrates an electrostatic intensifying lens and its control, as well as its effect on the kinetic energy of passing charged particles.

[0080] Figure 5 The diagram schematically illustrates an electrostatic intensifying lens and its control, as well as its effect on the kinetic energy of passing charged particles.

[0081] Figure 6 The configuration of an electrostatic enhancement lens in a multi-beam particle system is illustrated schematically.

[0082] Figure 7 Schematic illustration in accordance with Figure 6 In the case of the configuration of the intensifying lens, the electrostatic intensifying lens and its control, and its effect on the kinetic energy of the passing charged particles;

[0083] Figure 8 The configuration of an electrostatic enhancement lens in a multi-beam particle system is illustrated schematically.

[0084] Figure 9 This schematically illustrates a 4f system with an electrostatic intensifying lens in the cross region and the effect of the electrostatic intensifying lens on the particle optical beam path; and

[0085] Figure 10 A flowchart illustrating the method according to the present invention is shown schematically. Detailed Implementation

[0086] To the extent possible, in the following description of exemplary embodiments of the invention, components having similar functions and structures are indicated by similar or identical reference numerals. Thus, elements of an array (e.g., a plurality of first separately charged particle beams) can be indicated by a single reference numeral. Depending on the context, the same reference numeral may also indicate individual elements of the array. Each first separately charged particle beam (3.1, 3.2, 3.3) is an individual particle beam or sub-beam of the plurality of first separately charged particle beams (3).

[0087] Figure 1 The schematic diagram illustrates the basic features and functions of a multi-beam particle system 1. It should be noted that the symbols used in the figure are chosen according to the corresponding functions they represent. The type of multi-beam particle system 1 shown is a type of multi-beam particle microscope. However, the invention is not limited to multi-beam particle microscopes and... Figure 1The illustrations are for illustrative purposes only. A multi-beam particle system 1 is operated using multiple first charged particle beams 3 to generate corresponding multiple incident positions or beam spots 5 of the first charged particle beams on the surface 25 of an object 7, which may be, for example, a wafer or mask substrate, with its surface 25 disposed in the object plane 101 of the objective lens 102. For simplicity, only three first charged particle beams 3.1 to 3.3 and three corresponding incident positions 5.1 to 5.3 of the first charged particle beams on the object plane 101 are shown. The features and functions of the multi-beam particle system 1 can be implemented using electrons or other charged particles (e.g., ions, and particularly helium ions). Further details regarding the multi-beam particle system 1 are disclosed in International Patent Application WO 2021 / 018332 A1, filed June 16, 2021. The disclosure of that patent application is incorporated herein by reference in its entirety.

[0088] The multi-beam particle system 1 includes an object illumination unit 100 and a detection unit 200; and a beam splitter 400 for separating a second particle optical beam path 13 from a first particle optical beam path 11. The object illumination unit 100 includes a beam generating device 300 for generating a plurality of first separately charged particle beams 3, and is adapted to focus the plurality of first separately charged particle beams 3 on an object plane 101, wherein the surface 25 of the object 7 or wafer 7 has been positioned by a sample platform 500.

[0089] Beam generating apparatus 300 generates a plurality of first charged particle beam spots in an intermediate image plane 321. Beam generating apparatus 300 includes at least one charged particle source 301, such as electrons. At least one charged particle source 301 emits a diverging charged particle beam, which is collimated by at least one collimating lens 303, such that a collimated or parallel first charged particle beam 309 is formed. Collimating lens 303 typically includes one or more electrostatic or magnetic lenses or a combination of electrostatic and magnetic lenses. The collimated first charged particle beam 309 is incident on a multi-beam generator 305. A multi-beam generator 305 is described, for example, in US 2019 / 0259575 A1 and US 10 741355 B1; both documents are incorporated herein by reference in their entirety. Multi-beam generator 305 essentially includes a first porous plate or filter plate 304 irradiated by the subsequently collimated first charged particle beam 309. The first porous plate or filter 304 includes a plurality of holes arranged in a grid for generating a plurality of first individual charged particle beams 3, wherein these first individual charged particle beams 3 are formed when charged particles in the first charged particle beam 309 pass through the corresponding openings. The multi-beam generator 305 also includes at least one additional porous plate 306 disposed downstream of the first porous plate or filter 304 in the direction of the particle optical beam path. In this case, the direction of the particle optical beam path is specified by the direction of movement of the charged particles in the first charged particle beam 309. According to one example, the second porous plate 306 may include four or eight electrostatic elements for each of the plurality of openings, for example, to individually deflect each of the first individual charged particle beams 3. Together with the second field lens 303, the plurality of first individual charged particle beams 3 are focused in or directly in the vicinity of the intermediate image plane 321. Each of the charged particle source 301 and the active porous plate 306 is controlled by a primary path controller module 830, which is a component of the controller 800 of the multi-beam particle system 1.

[0090] Multiple focal points of the first individually charged particle beam 3 (which pass through the intermediate image plane 321) are imaged onto the object plane 101 by the field lens group 103 and the objective lens 102, in which the surface 25 of the object 7 lies. An electrostatic deceleration field is generated between the objective lens 102 and the object surface 25 by applying a voltage to the object 7 through the sample voltage source 503. The electrostatic deceleration field established by the sample voltage source 503 is used to set the landing energy EL of the first individually charged particle beam, such as primary electrons, for example, less than 1 keV, less than 800 eV, less than 500 eV, less than 300 eV, or even lower.

[0091] Figure 2Further details of the electrostatic deceleration field are schematically illustrated. Multiple individual charged particle beams 3 are generated from a collimated first charged particle beam 309 using a porous configuration 305 or a multi-beam generator 305. For simplicity, only three individual particle beams 3.1 to 3.3 are described; however, it is possible to generate, for example, more than 60, more than 90, or even more than 300 individual particle beams. A beam tube 151 (in which the multiple individual particle beams 3 are guided) is disposed downstream of the porous configuration 305 in the direction of the particle optical beam path 11. This beam tube 151 is connected to a voltage source providing the beam tube voltage VT. The first individual charged particle beam 3 has a constant kinetic energy ET from entering the beam tube 151 to exiting the beam tube 151 through the beam exit opening 153. The kinetic energy ET of the first individual charged particle beam 3, or electron beam, during its passage through the beam tube 151 is, for example, 20 keV, 30 keV, or 35 keV.

[0092] Multiple first-order particle beams 3 are imaged and formed into beam spots 5.1 to 5.3 in image plane 101 or object plane 101 by field lenses 333 and 103 and by objective lens 102. In the example shown, objective lens 102 is a magnetic lens having a winding 161 and pole piece 163, the pole piece 163 having a lower pole piece segment 165, and the magnetic field of magnetic lens 102 forming a gap along the axial direction with the lower pole piece segment 165. A current I is provided during operation of winding 161 to generate a focusing magnetic field (not shown here). Other types of magnetic lenses are also possible, for example, lenses with radial gaps for generating an immersion lens field or magnetic lenses with multiple windings and pole pieces. Beam splitter 400 is disposed above or partially integrated into magnetic lens 102 and configured to separate secondary electron beam 9 or second-order charged particle beam 9 along secondary particle optical beam path 13 and guide it to detection unit 200. Electrode 133 is disposed below the lower shoe section 165 and connected to a voltage source, such that a second voltage VE is provided at electrode 133. In the example shown, electrode 133 is specifically implemented as a separate electrode.

[0093] After leaving the beam tube 151, the multiple first-stage charged particle beams 3 decelerate from kinetic energy ET to a second kinetic energy EE. The voltage difference between VT and VE is responsible for generating the first electric field 135, which in... Figure 1The first electric field 135 is depicted by two equipotential lines. The correlation vector of the electric field is substantially parallel to the propagation direction of the first individual charged particle beam 3 and generates a decelerating force acting on the first individual charged particle beam 3. The first voltage VE is typically adjusted such that the second kinetic energy EE is in the range of less than 5 keV, less than 3 keV, or even less than 2 keV. A third or sample voltage VL is provided at the sample receiving pad 505, which is held and contacted with the sample 7 by the sample voltage source 503 during operation of the multi-beam particle system 1. A second electric field 137 is generated based on the voltage difference between VL and VE, which is almost parallel to the propagation direction of the first individual charged particle beam 3 and exerts a decelerating force on the first individual charged particle beam 3 or related particles. The third or sample voltage VL is adjusted such that the third kinetic energy or landing energy EL of an individual particle beam 3 (e.g., an electron in the described example) is in the range of < 800 eV, < 300 eV, or even < 100 eV. Both electric fields 135 and 137 form a deceleration field to reduce the kinetic energy of the first charged particle beam 3 before it is incident on the sample surface 25, which is disposed in the object plane 101. The first electric field 135 also forms an acceleration field for the second individual particle beam 9 or secondary electron 9 originating from the sample 7 or wafer 7. The second electric field 137 forms an extraction field for extracting and accelerating secondary particles or secondary electrons from the sample 7 or wafer 7. Therefore, the second electric field 137 is also referred to as extraction field 137.

[0094] Figure 2 The example shown illustrates two-stage deceleration fields 135 and 137, along with an additional electrode 133. However, different examples may provide only one deceleration field or extraction field 137, which is generated first between the beam exit opening 153 of the bundle tube 151 and the sample 7 disposed on the sample receiving pad 505. In this case, the beam exit opening 153 of the bundle tube 151 functions as the electrode 133 of the extraction field 137.

[0095] Figure 1 and Figure 2The object illumination unit 100 of the multi-beam particle system 1 shown also includes a collective deflection scanner 110 located near the intersection region 108 of the first separately charged particle beams 3. The collective deflection scanner 110 allows the first separately charged particle beams 3 to be collectively deflected to a scanning direction 143, which is orthogonal to the propagation direction of the first separately charged particle beams 3. In each of the described examples, the propagation direction of the first separately charged particle beams is the positive z-direction. Both the objective lens 102 and the collective scanning deflector 110 are centered on the optical axis Z (not shown) of the multi-beam particle system 1, which is orthogonal to the surface 25 of the sample or the surface 25 of the wafer. Multiple first separately charged particle beams 3 (which form beam spots 5 according to a grid configuration) are scanned synchronously on the surface 25 of the wafer or the surface 25 of the sample. According to one example, the grid configuration of the beam spots 5 of the multiple first separately charged particle beams 3 is a hexagonal grid of approximately 100 or more first separately charged particle beams 3, such as 91 beams, 100 beams, or even 300 or more beams. The beam spots 5 are spaced approximately 6 μm to 45 μm apart and have diameters less than 5 nm, such as 3 nm, 2 nm, or even smaller. According to one example, the beam spot size is approximately 3 nm, and the spacing between adjacent beam spots is approximately 8 μm. Multiple secondary electrons are generated at each sample location or scan location of the first individual charged particle beam, and thus in the region of the beam spot 5. Each secondary electron forms multiple second individual charged particle beams 9 or secondary electron beams 9, specifically, in a grid configuration of the same beam spot 5. The intensity of the secondary electron beam 9 formed at each beam spot or irradiation spot 5 depends on the intensity of the incident first individual charged particle beam 3 at the irradiation beam spot 5, the material composition 67, 69 and morphology of the object 7 under the corresponding irradiation beam spot 5, and the charge state of the sample 7 at the irradiation beam spot 5. The multiple second charged particle beams 9 are accelerated by the same electrostatic field between the objective lens 102 and the object surface 25 and are focused by the objective lens 102. The secondary electron beams 9 pass through the first collective scan deflector 110 in the opposite direction to the first individual particle beam 3. Multiple second charged particle beams 9 are collectively deflected by a collective scanning deflector 110. These beams are then deflected by a beam splitter 400 to reach the detection unit 200 along the second particle optical beam path 13. In this case, the multiple second charged particle beams 9 move in the opposite direction to the first charged particle beam 3, specifically using kinetic energy ES = ET - EL, and the beam splitter 400 separates the second particle optical beam path 13 from the primary particle optical beam path 11 by a magnetic field or a combination of magnetic and electrostatic fields.

[0096] The detection unit 200 images the second individual particle beam 9 or secondary electron beam 9 onto the image sensor 600, thereby forming multiple second charged beam spots 15. The detector or image sensor 600 contains multiple detection pixels or individual detectors. The intensity of each second charged beam spot 15 is detected separately, and the characteristics of the object surface 25 are recorded with high resolution and high throughput for a large image field of the object 7. For example, using a grid of 10 x 10 individual particle beams 3 with a spacing of 8 µm, a raster scan of an image field of approximately 88 μm x 88 μm can be performed by an image scanning procedure of the collective scanning deflector 110, with an image resolution of, for example, 2 nm or better. The image field is scanned using a half-beam spot size, so that each image line of each individual particle beam 3 has a total of 800 pixels, such that the image field established by 100 individual particle beams 3 contains approximately 6.4 billion pixels (gigapixels). Digital image data is collected by the controller 800. Details relating to image data collection and image data processing (e.g., using parallel data processing) are described in International Patent Application WO 2020 151 904 A2 and U.S. Patent Application US 9 536 702 B2, the contents of which are incorporated herein by reference in their entirety.

[0097] The detection unit 200 also includes at least one second collective scanning deflector 222 connected to the scanning deflector controller module 860. The scanning deflector controller module 860 is configured to compensate for deviations in the deflection force of the first collective scanning deflector 110 in the common particle optical beam path, such that the position of the second separate particle beam 9 incident on the image sensor 600, and therefore the position of the beam spot 15, remains constant. Differences in the collective deflection according to the first collective scanning deflector 110 occur because the kinetic energy ET of the first separate particle beam 3 differs from the kinetic energy ES of the second separate particle beam 9. Furthermore, the multi-beam particle system 1 may optionally include a scalable monitoring system 230. Monitoring systems and methods for detecting the charging effect of charged samples are described in detail in patent applications PCT / EP2022 / 061042 and DE 10 2022114923.4, the contents of which are incorporated herein by reference in their entirety. The detection unit 200 will now be described in detail.

[0098] The image sensor 600 consists of a patterned configuration or array of detection regions that is compatible with or corresponds to the grid configuration of the second individual particle beam focused onto the image sensor 600 by the detection unit 200. This allows each of the second individual particle beams 9 to be detected independently of the remaining second individual particle beams 9 when incident on the image sensor 600. Figure 1The image sensor 600 shown may be an electron-sensitive detection array, such as a CMOS detector or a CCD sensor. This electron-sensitive detection array may include electron-photon conversion units, such as scintillation elements or arrays or grids of scintillation elements. In another exemplary embodiment, the image sensor 600 may be designed as an electron-photon conversion unit disposed in the focal plane of the formed second particle beam 9 or beam spot 15. Figure 3 In this embodiment variant, described by way of example, the image sensor 600 may further include an optical relay system comprising a converging lens 605 and a zoom lens 611 for imaging and directing photons generated at the incident point 15 via an electro-photon conversion unit 602 to a special photon detection element 623, such as multiple light multipliers or avalanche photodiodes. For example, this image sensor 600 is disclosed in US 9,536,702 B2, which is cited above and incorporated herein by reference in its entirety. In the described example, the image sensor 600 also has a selectively scalable monitoring system 230 comprising a beam-splitting mirror 237, an imaging lens 235, and a high-resolution CMOS sensor 232.

[0099] Preferably, the sample platform 500 remains stationary while simultaneously scanning the sample 7 using multiple individual charged particle beams 3 to record an image field; the sample platform 500 moves after recording the image field and records the next image field. According to an alternative embodiment, the sample platform 500 moves continuously in a second direction while simultaneously recording an image by scanning multiple individual charged particle beams 3 in a first direction using a collective scanning deflector 110. The movement and position of the sample platform 500 are monitored and controlled by known sensor systems, such as laser interferometers, grating interferometers, confocal microlens arrays, etc.

[0100] When recording an image, the controller 800 is configured to trigger the image sensor 600 to record intensity signals corresponding to multiple times from multiple second separate particle beams 9 at predetermined time intervals, and to extract and stitch together a digital image of the image field from all sampling positions or scanning positions of multiple first separate particle beams 3.

[0101] The controller 800 of the multi-beam particle system 1 also includes an image controller module 810 configured to receive a data stream from the image sensor 600 and establish a digital image of the surface of the sample 7 during operation. The controller also includes a secondary path controller module 840 configured to control the detection unit 200. The controller 800 further includes a primary path controller module 830 configured to control elements of the object illumination unit 100. The controller 800 also includes a sample platform controller module 850 configured to control the positioning and alignment of the sample platform and control the voltage supplied via the sample voltage source 503. The controller 800 also includes a scan deflector controller module 860 configured to control the scanning operation or scanning procedure via a first collective scan deflector 110 and via a second deflection system 222. Furthermore, the controller 800 includes a processor 880 configured to control the inspection of sample 7, and also configured to control the aforementioned modules (i.e., 810, 820, 830, 840, 850, 860) and a memory 890 for storing software, operating instructions, and image data. Additionally, the processor 880 of the controller 800 is connected to a user interface IX for exchanging data, operating instructions, software, or user interaction.

[0102] The controller 800 of the multi-beam particle system 1 also includes a contrast controller module 870, which is connected to the processor 880 of the controller 800. The contrast controller module 870 is configured to receive instructions from the processor 880 of the controller for the purpose of compensating for charging effects when a second individual particle beam 9 is imaged on the image sensor 600. The contrast controller module 870 is connected to a sensor controller module 820, which in turn is connected to a monitoring system 230.

[0103] According to the present invention, the electrostatic intensifying lens 112 can now be integrated into the multi-beam particle system 1 described exemplarily above. In this case, the electrostatic intensifying lens 112 is disposed in the intersection region 108 of the first separately charged particle beam 3 in the primary particle optical beam path 11. Furthermore, this intersection region 108 is located in the upper focal plane of the objective lens 102. The controller 800 or one of its multiple modules (e.g., primary path controller module 830) is configured to provide voltage via a voltage supply unit ( Figures 1 to 3 (Not explicitly shown) A high voltage VB is provided at the electrostatic intensifying lens 112, such that the first separately charged particle beam 3 passes through the cross region 108 with progressively increasing kinetic energy, thereby reducing aberrations caused by Coulomb interactions between the first separately charged particle beams 3 within the cross region 108. Figure 1 The position of the electrostatic intensifying lens 112 is schematically shown by arrows in the image. Details of the electrostatic intensifying lens 112 itself are shown in the image. Figure 1 It is not explicitly stated in the document. Instead... Figure 4The electrostatic intensifying lens 112 and its control are schematically illustrated, as well as its effect on the kinetic energy of charged particles passing through it:

[0104] Figure 4 The electrostatic enhancement lens 112, initially depicted below, is essentially a single lens in the illustrated example. In this case, the single lens comprises a first (upper) electrode 112a, a second (center) electrode 112b, and a third (lower) electrode 112c. In this case, electrodes 112a, 112b, and 112c can be designed, for example, as thin plates with a central opening, thus realizing a tube lens or a tube lens segment. In this case, the central opening is centrally located on the particle optical axis Z or centered relative to the first particle optical beam path 11. Voltages can be applied to the first electrode 112a, the second electrode 112b, and the third electrode 112c, respectively. In the illustrated example, the voltage supply is controlled in each case by a primary path controller module 830. For this purpose, a voltage VB0 is provided at the first electrode 112a of the electrostatic enhancement lens 112. In the illustrated example, the same voltage VB0 is also provided at the third electrode 112c of the electrostatic enhancement lens 112. Conversely, a high voltage VB is provided at the second electrode 112b. For example, the provided voltage VB0 can be a low voltage. Preferably, the low voltage VB0 can also be 0 V, i.e., ground potential. For example, the enhanced high voltage VB can be ≥10 kV or ≥15 kV. Figure 4 This only illustrates the principle in this respect. Due to the potential difference between the first electrode 112a and the second electrode 112b (and under appropriate polarity), the first separately charged particle beam 3 is accelerated in the region between electrodes 112a and 112b, and its kinetic energy increases significantly. Then, the first separately charged particle beam 3 enters the tube lens section or the center electrode 112b with maximum kinetic energy Ekin. max Movement. Due to the potential difference between electrodes 112b and 112c, the charged particles or the first separately charged particle beam 3 are significantly decelerated after emerging from the central electrode 112b, decreasing to the original kinetic energy EPB0 that the charged particles or particle beam 3 already possessed when entering the acceleration field of the electrostatic enhancement lens 112. For example, this kinetic energy EPB0 can be compared with... Figure 2 The kinetic energy ET of the path shown in the diagram is the same. If the electrostatic intensifying lens 112 is precisely designed as a single lens, the kinetic energy of the first separately charged particle beam 3 entering the electrostatic intensifying lens 112 is exactly the same as the kinetic energy of the first separately charged particle beam 3 exiting the electrostatic intensifying lens 112. Therefore, in the intersection region 108, the kinetic energy increases significantly segment by segment, or more precisely, only significantly segment by segment.

[0105] Figure 5 Show Figure 4A slight modification to the example shown: In this case, the electrostatic intensifying lens 112 is not precisely designed as a single lens, but rather essentially designed as a single lens 112. Like according to Figure 4 In the aforementioned example, a high voltage or an enhanced high voltage potential VB is applied to the second electrode 112b. However, according to Figure 5 The two low-voltage potentials at the first electrode 112a and the third electrode 112c of the electrostatic intensifying lens 112 are chosen to be slightly different, not identical. In the example shown, low-voltage potential VB1 is applied to the first electrode 112a, and low-voltage potential VB2 is applied to the third electrode 112c. Therefore, the kinetic energy of the charged particles, or the first separately charged particle beam 3, entering the electrostatic intensifying lens 112 is slightly different from its kinetic energy leaving the electrostatic intensifying lens 112. Specifically, Figure 5 The incident kinetic energy EPB1 is slightly higher than the exit kinetic energy, at which point the kinetic energy is only EPB2, where EPB1 > EPB2. However, the maximum kinetic energy inside the central electrode 112b is the same in both cases. Theoretically, the exit kinetic energy EPB2 of the electrostatic enhancement lens 112 may also be greater than the entry kinetic energy, therefore the following applies: EPB2 > EPB1. The following facts should be noted in this paper: Figure 5 The kinetic energy in the diagram is only a schematic drawing and not an actual scale.

[0106] Since the kinetic energy of the first separate particle beam 3 increases significantly in a targeted manner and therefore only segmentally in the cross region 108, it is not necessary to modify the voltage applied to other components of the multi-beam particle system 1 compared to the prior art. In particular, in absolute terms, it is not necessary to further increase the high voltage applied to the charged particle source 301, nor is it necessary to provide a high voltage at the sample platform 500 or at the sample receiving pad 505 (via the current-voltage source 503). Instead, the first high voltage V1 provided at the particle source by the voltage providing unit can satisfy the following relationship in absolute terms: 20 kV ≤ V1 ≤ 40 kV, preferably 25 kV ≤ V1 ≤ 35 kV. Furthermore, in absolute terms, the second high voltage V2 provided at the sample can be subject to the following relationship: 20 kV ≤ V2 ≤ 40 kV, preferably 25 kV ≤ V2 ≤ 35 kV. Furthermore, even when the electrostatic enhancement lens 112 is implemented, a voltage of no more than a low voltage Vm can be provided at the aperture configuration 305 or the multi-beam generator 305 (also referred to as a micro-optical unit). Preferably, a low voltage Vm, satisfying the following relationship in absolute value, can be provided at the aperture configuration 305: 0 V ≤ Vm ≤ 100 V, preferably 0 V, i.e., a ground potential. In this case, a ground potential or at least only a low voltage potential can also be provided to the beam tube configuration 151.

[0107] This allows the first separate particle beam 3 to have its maximum kinetic energy Ekin in the region of the electrostatic enhancement lens 112 within the first particle optical beam path 11 between the charged particle source 301 and the sample 7. max Therefore, in the cross region 108, the maximum potential growth ΔVB brought about by the electrostatic enhancement lens 112, in absolute terms, has the following relationship: ΔVB ≥ 10 kV, preferably ΔVB ≥ 15 kV. For example, the high voltage VB at the electrostatic enhancement lens 112 or the second (center) electrode 112b can be VB ≥ 10 kV, preferably VB ≥ 15 kV.

[0108] In this case, the length LB of the electrostatic intensifying lens 112 along the particle optical axis Z is very short; for example, the following relationship can be applied: 2 mm ≤ LB ≤ 10 mm. For example, in... Figure 4 and Figure 5 The length LB is drawn in the middle, and it is the same as the length in the direction of the particle optical beam path 11 in the primary path, where the electrostatic enhancement lens 112 is generally effective. In this case, the length LB basically corresponds to the path between the electrodes or counter electrodes of the electrostatic enhancement lens. Furthermore, according to one example, the length LBm of the center electrode 112b can be subject to the following relationship: 1.5 mm ≤ LBm ≤ 4.5 mm.

[0109] Figure 6 The configuration of the electrostatic enhancement lens 112 in a multi-beam particle system 1 is schematically shown, for example, in an inspection system or a lithography system. As... Figure 1 As explained, a collective scanning deflector 110 for grating scanning of sample 7 is also disposed near the intersection region 108. This collective scanning deflector 110 includes an upper scanning deflector 110a and a lower scanning deflector 110b. An electrostatic intensifying lens 112 or its second (center) electrode 112b is now disposed between the upper scanning deflector 110a and the lower scanning deflector 110b. In this case, the upper scanning deflector 110a, the lower scanning deflector 110b, and the center electrode 112b of the intensifying lens 112 are located within the beam tube interruption segment: in Figure 6In the exemplary embodiment shown, the beam tube 151 is divided into a first (upper) beam tube segment 151.1 and a second (lower) beam tube segment 151.2. In this case, a DC voltage VT1 is applied to the first (upper) beam tube segment 151.1. A DC voltage VT2 is applied to the second (lower) beam tube segment 151.2. The provision of DC voltages VT1 and VT2 is controlled by a primary path controller module 830. Voltages VT1 and VT2 may be different, or they may be the same. Together with the electrode 112b of the electrostatic enhancement lens 112, the overall design of the electrostatic enhancement lens 112 substantially corresponds to a single lens when a high voltage or a high voltage potential VB is applied. In other words, the first electrode 112a of the electrostatic enhancement lens 112 is realized by the exit region 154 of the first beam tube segment 151.1, and the third electrode 112c of the electrostatic enhancement lens 112 is realized by the incident region 155 entering the second beam tube segment 151.2.

[0110] According to an alternative exemplary embodiment, an offset voltage VB may also be applied to one of the scan deflectors 110a, 110b (not shown here). In this case, another scan deflector 110b, 110a and one of the bundle tube segments 151.1, 151.2 may form the counter electrode of the electrostatic enhancement lens 112. More generally, at least one of the electrodes 112a, 112b, 112c of the electrostatic enhancement lens 112 may be achieved by an offset potential at a multipole electrode, for example, in one of the scan deflectors 110a, 110b.

[0111] When the electrostatic intensifying lens 112 or the voltages VT1, VB, and VT2 applied thereto are provided or controlled by the primary path controller module 830, the voltage provided at the collective deflection scanner 110 is provided or controlled by the scan deflector controller module 860. In the example shown, the upper scan deflector 110a is in the form of an electrostatic octet electrode, wherein a voltage V8a is applied to the octet electrode. In this case, individual voltages can be applied to each of the eight electrodes of the octet. The corresponding statement applies to the lower scan deflector 110b implemented as an electrostatic octet electrode, wherein an individual adjustable voltage can be applied to each of the eight electrodes; Figure 6 The voltage V8b in the text symbolically describes this.

[0112] Figure 7 The electrostatic intensifying lens 112 and its control are schematically shown, along with the effect on the kinetic energy of charged particles passing through it, according to... Figure 6In the configuration of the enhancement lens 112, the electrostatic enhancement lens 112 includes a beam exit region 154 of a first (upper) beam tube segment 151.1 serving as a first electrode and a beam entrance region 155 of a second (lower) beam tube segment 151.2 serving as a third electrode. The second electrode (i.e., the center electrode 112b of the electrostatic enhancement lens 112) is positioned centrally. This forms a single lens with voltages VT1, VB, and VT2 applied to its electrodes. Voltage VB is a high voltage potential. The applied voltages VT1, VB, and VT2 provided by the primary path controller module 830 are static voltages. Conversely, the upper scan deflector 110a and lower scan deflector 110b of the collective scan deflector 110 are dynamically controlled. The specific control of the multi-electrode electrode (e.g., an octet electrode) depends on the scanning position of the first individual particle beam 3 on the sample. Therefore, this also facilitates the control of the collective scan deflector 110 by individual modules, specifically the scan deflector controller module 860 in the illustrated example.

[0113] As described above, the voltage applied to the center electrode 112b of the electrostatic enhancement lens 112 is a high voltage. Conversely, the voltage supplied at the multipole electrodes 110a, 110b of the collective scanning deflector 110 is a low voltage, for example, approximately 50 V.

[0114] Figure 7 The control of the five electrodes in total is also reflected in the correlation diagram of the kinetic energy of the charged particles that form the first charged particle beam 3: Figure 7 The diagram illustrates the kinetic energy under two different controls for the upper scanning deflector 110a and the lower scanning deflector 110b in each case. Solid line A1 shows the kinetic energy distribution under the first control case of the collective scanning deflector 110a, and dashed line A2 shows the kinetic energy under the second control case. In the first control case, the kinetic energy of the charged particles decreases slightly, thus the particles decelerate slightly in the region between the first electrode 112a of the intensifying lens 112 and the upper scanning deflector 110a. After passing through the upper scanning deflector 110a, there is a strong increase in kinetic energy before entering the center electrode 112b of the electrostatic intensifying lens 112. The maximum kinetic energy is then reached at Ekin. max The kinetic energy EPB passes through the center electrode 112b. Then, the kinetic energy between the center electrode 112b of the electrostatic intensifier lens 112 and the lower scanning deflector 110b decreases sharply. Then, between the exit of the lower scanning deflector 110b and the entrance of the beam tube incident region 155 or the third electrode 112c of the electrostatic intensifier lens 112, the kinetic energy decreases slightly again.

[0115] In the second control case of the collective scanning deflector 110, initially, the kinetic energy between the first electrode 112a or the beam tube exit region 154 increases slightly, and then a significant increase in velocity or maximum kinetic energy Ekin is obtained between the upper deflector 110a and the center electrode 112b of the electrostatic intensifying lens 112. max The maximum kinetic energy during the second control period of the collective scanning deflector 110 is substantially equivalent to the kinetic energy during the control period of the collective scanning deflector in the first control case. The kinetic energy then decreases significantly, specifically, in the second control case, slightly lower than in the first control case of the collective scanning deflector 110. Then, the kinetic energy between the lower scanning deflector 110b and the beam tube incident region 155 (which serves as the third electrode 112c of the electrostatic enhancement lens 112) decreases slightly further. Although there is a slight potential difference or kinetic energy difference overall when entering and leaving the electrostatic enhancement lens 112, Figure 7 The electrostatic enhancement lens design in the example shown is also essentially a single-lens design.

[0116] Figure 8 A further configuration of the electrostatic intensifying lens 112 in the multi-beam particle system 1 is schematically shown. The multi-beam particle system can be, for example, an inspection system or a photolithography system. Figure 8 In the example shown, the lens effect of the electrostatic enhancement lens 112 is achieved at least in part by the offset voltage at the multipole electrodes. Specifically, in Figure 8 In the exemplary embodiment shown, the collective deflection scanner incorporates opposing electrodes (i.e., the first and third electrodes of the electrostatic intensifying lens 112): in principle, all individual electrodes in the multi-electrode array can be individually controlled. This is the case for the upper scanning deflector 110a and the lower scanning deflector 110b. Furthermore, the same offset voltage can be selectively applied to all individual electrodes of the multi-electrode array. Therefore, the multi-electrode array also has a circular lens component, and in addition to collective deflection, the effect of a circular lens is also achieved.

[0117] In the example shown, the multi-beam particle system 1 includes a beam tube configuration 151, which includes a beam tube extension as shown in the example, namely, a section extending into the objective lens 102. An electrostatic intensifying lens 112 is disposed within this beam tube extension. Therefore, this example does not discuss the beam tube interruption segment in the region of the intersection area 108.

[0118] The statically supplied enhanced high voltage VB is again applied to the center electrode 112b of the electrostatic enhancement lens 112. The voltage V8a already supplied at the upper scan deflector 110a is dynamically supplied and overlaid with a static offset. Therefore, the voltage V8b at the lower scan deflector 110b is also dynamically supplied and overlaid with a static offset voltage. The two offset voltages may be the same, but they may also be different from each other.

[0119] Figure 9A schematic illustration shows a 4f system with an electrostatic intensifying lens 112 in the intersection region 108, and the effect of the electrostatic intensifying lens on the path of the particle optical beam. The 4f system is a schematic representation of an imaging system. Essentially, the 4f system comprises a first lens with a focal length f1 and a second lens with a focal length f2. The magnification of the system is M = f2 / f1. The intermediate image plane between the two parts of the system is the plane in which the principal rays of the individual particle beams move parallel to each other (this is in...). Figure 9 (This cannot be identified by simplified representation). If the aperture is configured in the intermediate image plane of the cross region 108, or more precisely, in the cross plane 108, then this will not change the telecentric characteristics of the imaging system.

[0120] Please refer to the multi-beam particle system 1. This means that the first separate particle beam 3 must be telecentric when incident on the object plane 101, for inspection or illumination purposes with good uniformity. Therefore, the second lens in the 4f system corresponds to the objective lens 102. Therefore, for telecentric imaging, the upper focal plane of the objective lens 102 must coincide with the intersection region 108. Therefore, the electrostatic intensifying lens 112 must be located in the upper focal plane of the objective lens 102, or in other words, in the intersection region 108. As long as the electrostatic intensifying lens 112, or when designed as a single lens, has its center electrode 112b located within the intersection region 108, the setting of the electrostatic intensifying lens 112 will not change the telecentric characteristics of the first separate particle beam 3 when incident on the object plane 101.

[0121] exist Figure 9 The example shown also depicts the intermediate image plane 321 and the field lens 103. In the example shown, the first particle beams 3 are parallel to each other in the intermediate image plane 321. However, this is not necessarily the case.

[0122] If the excitation of the electrostatic intensifier lens 112 is changed now, this will change the working distance WD or the position of the object plane 101 to the position of the object plane 101'. The first setting member controlled by the controller 800 modifies the enhanced high voltage VB applied to the electrostatic intensifier lens 112 to provide this variation for the electrostatic intensifier lens 112. Alternatively, this modified setting of the electrostatic intensifier lens 112 can also modify the numerical aperture NA of the first separate particle beam 3 when incident on the object planes 101, 101'.

[0123] Furthermore, according to one embodiment of the invention, a second setting member different from the first setting member is provided. In this case, the controller 800 is configured to control the second setting member such that the modified working distance WD of the first separate particle beam 3 is corrected or modified, and / or the modified numerical aperture NA of the first separate particle beam 3 when incident on the object plane 101 is corrected or modified. Generally, with the application of a variable electrostatic enhancement high voltage VB to the electrostatic enhancement lens 112, the multi-beam particle beam system 1 includes further degrees of freedom. Therefore, modifications to other imaging parameters caused by changes in the refractive power of the electrostatic enhancement lens 112 can be corrected. However, as long as the electrostatic enhancement lens 112 is substantially located within the cross region 108, the magnification and telecentricity do not change even when the control of the electrostatic enhancement lens 112 is changed. In this case, geometrically, the parameters are substantially maintained according to the... Figure 9 The 4F system.

[0124] To maintain the telecentricity of the entire system, in a system according to a preferred embodiment of the invention, the objective lens focal length f2 and the field lens focal length f1 can be varied simultaneously. The impact on the imaging scale is very small and tolerable. Even if the aperture plane is slightly shifted in the region of the electrostatic intensifying lens 112, the intersection area remains within the electrostatic intensifying lens 112. Figure 9 In the middle, the modified position of object plane 101 is indicated by the dashed line bundle path.

[0125] The change in the refractive power of objective lens 102 can be implemented in different ways: according to a variation of the first embodiment, the excitation or current I of the objective lens can be changed (see...). Figure 2 Alternatively or in addition to this, the change in the refractive index of objective lens 102 may be caused by a modification control of collective scanning deflector 110 or at least one of scanning deflectors 110a, 110b. Alternatively or in addition to this, a modified voltage, particularly a modified low voltage VT2, may be applied to the second (lower) bundle segment 151.2 when bundle configuration 151 is divided into a first (upper) bundle segment 151.1 and a second (lower) bundle segment 151.2. The second lower bundle segment 151.2 is located within the magnetic field of objective lens 102; therefore, the modified voltage at the lower bundle segment 151.2 causes a change in the velocity of charged particles in the first separate particle beam 3 within the magnetic field of objective lens 102, thereby changing the refractive index of objective lens 102.

[0126] Alternatively, an electrostatic correction element may be configured in the magnetic field of the objective lens 102.

[0127] The possibility of modifying the refractive index of the described objective lens 102 can be realized by a second setting member (not shown here), which is controlled by the controller 800 or a component of the controller 800.

[0128] According to an alternative embodiment variant of the invention, the refractive index of objective lens 102 remains unchanged, and only the refractive index of field lens 103 is adjusted. This modifies the input telecentrism of the first separately charged particle beams 3.1, 3.2, 3.3 in the intermediate image plane 321, and thus modifies the input according to Figure 9 The input telecentrism in a 4f system. The input telecentrism can be determined by the second field lens 333 (see...). Figure 1 Alternatively, the telecentricity setting component can be modified or adjusted. Overall, even in this embodiment variant, the 4f system remains telecentric, or the first separate particle beam 3 is incident on the object plane 101 in a telecentric manner.

[0129] In the two embodiment variations described in detail above, the extraction field between electrode 133 and sample or wafer 7 can remain unchanged.

[0130] Figure 10 A flowchart illustrating a method for operating a multi-beam particle system 1 according to the present invention is shown, as described above in several embodiments. According to a first method step S1, a multi-beam particle system 1 is provided having a crossing region 108 of a first separately charged particle beam 3 in the illumination beam path 11 at the upper focal plane of the objective lens 102.

[0131] In the second method step S2, the kinetic energy of the first separate particle beam 3 is increased in segments in the cross region 108, the purpose of which is to significantly reduce the Coulomb interaction between the first separate charged particle beams 3.

[0132] According to the third method step S3, the maximum kinetic energy of the first separate particle beam 3 is modified in the intersection region, thereby modifying at least one imaging parameter of the multi-beam particle system 1 when the first separate particle beam 3 is incident on the object plane 101. For example, this could be the working distance WD or the refractive power of the objective lens 102; in addition, or alternatively, it is also related to the numerical aperture NA. Although the maximum kinetic energy of the first separate particle beam 3 in the intersection region 108 is changed, other imaging parameters are not changed or at least not significantly changed; specifically, the telecentricity of the first separate particle beam when it is incident on the object plane 101 is maintained.

[0133] According to another method step S4, at least one modified imaging parameter is corrected, such as the modified working distance WD and / or the modified numerical aperture NA.

[0134] The method steps of the method according to the invention can be implemented by the above-described features of the multi-beam particle system 1, and particularly by its particle optical elements, such as the electrostatic enhancement lens 112 and the described controller 800.

[0135] Overall, the exemplary embodiments described in the sections relating to the figures should not be construed as limiting the invention, but are provided only for a better understanding of the invention.

[0136] This invention relates to a multi-beam particle system 1 with better resolution and faster recording speed. For this purpose, an electrostatic intensifying lens 112 is disposed in the upper focal plane of an objective lens 102 flush with the intersection region 108 of the primary particle beam 3. The electrostatic intensifying lens 112 is specifically designed to significantly increase the kinetic energy of the primary beam 3 in the intersection region 108, which is why the Coulomb interaction between the charged particles 3 is weakened.

[0137] List of reference numerals

[0138] 1. Multi-beam particle system

[0139] 3. Primary particle beam (first secondary particle beam)

[0140] 5 beams, the incident position of the first separate particle beam

[0141] 7 objects, samples

[0142] 9 Secondary particle beam / (Secondary particle beam)

[0143] 13 Secondary Particle Optical Beam Path

[0144] 15 beams, the incident point of the second separate particle beam

[0145] 25. Surface of an object or sample

[0146] 67 First Material Composition

[0147] 69 Second material composition

[0148] 100 object lighting units

[0149] 101 Object Plane

[0150] 102 Objective Lens

[0151] 103 field lens

[0152] 108 Intersection Area

[0153] 110 Collective Scan Deflector (Single Path)

[0154] 110a Upper Scan Deflector

[0155] 110b downscan deflector

[0156] 112 Electrostatic Intensifier Lens

[0157] The first electrode of the 112a electrostatic intensifying lens

[0158] The second electrode of the 112b electrostatic intensifier lens

[0159] The third electrode of the 112c electrostatic intensifier lens

[0160] 133 electrode

[0161] 135 First Electric Field

[0162] 137 Second Electric Field

[0163] 151 bundle tube

[0164] 151.1 First (Upper) Bundle Section

[0165] 151.2 Second (Lower) Bundle Section

[0166] 153 beam exit openings

[0167] 154 beam tube exit area

[0168] 155mm beam tube incident area

[0169] 161 winding

[0170] 163 Extreme Boots

[0171] 165 Lower Extreme Boot Section

[0172] 200 detection units

[0173] 222 Second Collective Deflection Scanner (Secondary Path)

[0174] 225 Image plane of the second separate particle beam

[0175] 230 monitoring system

[0176] 232 high-resolution sensor

[0177] 235 Imaging Lens

[0178] 237 beam splitter mirror

[0179] 300-beam generation equipment

[0180] 301 Particle Source

[0181] 303 collimating lens system, focusing lens system

[0182] 304 filter plate

[0183] 305 multi-beam generator, multi-hole configuration

[0184] 306 perforated plate

[0185] 309 primary particle beam

[0186] 321 Intermediate Image Plane

[0187] 331 First Field Lens

[0188] 333 Second Field Lens

[0189] 400 beam splitter

[0190] 500 sample platform

[0191] 503 Sample Voltage Source

[0192] 505 Sample Receiving Pad

[0193] 600 image sensor

[0194] 602 Electron-Photon Converter, Scintillator Plate

[0195] 605 Converging Lens

[0196] 609 Light

[0197] 611 zoom lens

[0198] 613 light incident surface

[0199] 615 fiber optic cable

[0200] 617 motor, rotary motor

[0201] 623 detection element

[0202] 630 Displacement Direction

[0203] 800 controller

[0204] 810 Image Controller Module

[0205] 820 Sensor Controller Module

[0206] 830 Primary Path Controller Module

[0207] 840 Secondary Path Controller Module

[0208] 850 Sample Platform Controller Module

[0209] 860 Scan Deflector Controller Module

[0210] 870 Comparison Controller Module

[0211] 880 processor for controller

[0212] 890 memory

[0213] IX User Interface

Claims

1. A multi-beam particle system, comprising: A particle source, used to emit beams of charged particles; A porous configuration comprising at least one porous plate having multiple channel openings, the porous configuration being configured to generate a first field from the charged particle beam of a plurality of first separately charged particle beams; A first particle optical unit having a first particle optical beam path is configured to image the generated first particle beam on the sample surface in the object plane, such that the first particle beam is incident on the sample surface at the incident position where the second field is formed. A magnetic and / or electrostatic objective lens through which the first individual particle beam passes; A sample platform is used to configure the sample so that its surface lies in the object plane. An electrostatic intensifying lens, wherein the first particle optical beam path includes a cross region of the first separately charged particle beam, the electrostatic intensifying lens is disposed in the region of the upper focal plane of the objective lens, and the electrostatic intensifying lens is disposed in the region of the cross region; Voltage supply unit; as well as The controller is used to control this multi-beam particle system. The controller is configured to provide an enhanced high voltage VB at the electrostatic enhancement lens via the voltage supply unit, so that the first individually charged particle beam passes through the cross region in segments with significantly increased kinetic energy, thereby reducing aberrations caused by Coulomb interactions between the individual particle beams in the cross region.

2. The multi-beam particle system as described in claim 1, in, In the particle optical beam path between the particle source and the sample, the first separate particle beam has its maximum kinetic energy in the region of the enhancing lens and therefore in the intersection region; as well as In absolute terms, the maximum potential increase ΔVB caused by the enhancing lens is subject to the following relationship: ΔVB ≥ 10kV, and in particular ΔVB ≥ 15 kV.

3. The multi-beam particle system as described in any of the preceding claims, The controller is configured to provide a first high voltage V1 at the particle source via the voltage supply unit. The controller is configured to provide a low voltage Vm at the porous configuration via the voltage supply unit, and The controller is configured to provide a second high voltage V2 at the sample platform and thus at the sample via the voltage supply unit.

4. The multi-beam particle system as described in claim 3, in, The first high voltage V1 and the second high voltage V2 have the same sign; and In absolute terms, the first high voltage V1 at the particle source is subject to the following relationship: 20 kV ≤ V1 ≤ 40 kV, particularly 25 kV ≤ V1 ≤ 35 kV; and Specifically, in absolute terms, the second high voltage V2 at the sample plateau is subject to the following relationship: 20 kV ≤ V2 ≤ 40 kV, particularly 25 kV ≤ V2 ≤ 35 kV; and In absolute terms, the low voltage Vm at this porous configuration is subject to the following relationship: 0 V ≤ Vm ≤ 100V, especially 0 V.

5. The multi-beam particle system as described in claim 4, in, The symbol for the enhanced high voltage VB differs from the symbols for the first high voltage and the second high voltage; and In absolute terms, the enhanced high voltage VB at the electrostatic enhancement lens is subject to the following relationship: VB ≥ 10kV, and in particular VB ≥ 15 kV.

6. The multi-beam particle system as described in any of the preceding claims, in, The length LB of the electrostatic intensifying lens along the particle optical axis Z is subject to the following relationship: 2 mm ≤ LB ≤ 10 mm; and / or The length LBm of the center electrode of the electrostatic enhancement lens is subject to the following relationship: 1.5 mm ≤ LBm ≤ 4.5 mm.

7. The multi-beam particle system as described in any of the preceding claims, in, From a functional perspective, this electrostatic enhancement lens is essentially implemented as a single lens.

8. The multi-beam particle system as described in any of the preceding claims, The lens effect of the electrostatic enhancement lens is achieved at least in part by the offset voltage at the multipole electrode.

9. The multi-beam particle system as described in any of the preceding claims, The multi-beam particle system includes a beam tube configuration that guides at least the first individual particle beam in at least segmental sections within the beam tube configuration; and The bundle tube configuration includes a bundle tube extension that extends into the objective lens; and The electrostatic enhancement lens is disposed within the extension section of the beam tube.

10. The multi-beam particle system as described in any one of claims 1 to 8, The multi-beam particle system includes a beam tube configuration that guides at least the first individual particle beam in at least segmental sections within the beam tube configuration; and in, The bundle configuration includes a bundle interruption segment in the region of the cross region, and the bundle configuration is subdivided into a first bundle segment and a second bundle segment; and The first upper electrode of the electrostatic enhancement lens is formed by the first bundle tube segment, and a low voltage VT1 has been applied to it. The second central electrode of the electrostatic enhancement lens is disposed within the interrupted section of the beam tube, and the enhanced high voltage VB is provided at the second central electrode; and The third lower electrode of the electrostatic enhancement lens is formed by the second bundle segment, and a low voltage VT2 has been applied to it.

11. The multi-beam particle system as described in any of the preceding claims, in, The multi-beam particle system includes a collective scanning deflector having an upper deflection unit located in the upper cross region and a lower deflection unit located in the lower cross region. as well as The central electrode of the electrostatic enhancement lens is disposed between the upper deflection unit and the lower deflection unit.

12. The multi-beam particle system as described in any of the preceding claims, The multi-beam particle system further includes a first pre-defined component; and The controller is configured to control the first setting member to modify the enhanced high voltage VB applied to the electrostatic enhancement lens, thereby modifying the working distance WD and / or the numerical aperture NA of the first separate particle beam incident on the object plane.

13. The multi-beam particle system as described in claim 12, It also includes a second setting member, which is different from the first setting member; and The controller is configured to control the second setting member such that the modified working distance WD of the first separate particle beam is corrected and / or the modified numerical aperture NA of the first separate particle beam incident on the object plane is corrected.

14. The multi-beam particle system as described in claim 13, The second setting member is configured to induce a modification excitation in the objective lens and / or field lens.

15. The multi-beam particle system as described in claims 11 and 13, The second setting component is configured to cause modification control of the collective scan deflector.

16. The multi-beam particle system as described in claims 10 and 13, The second setting component is configured to apply a modification voltage VT2 to the second bundle segment.

17. The multi-beam particle system as described in claim 13, The second setting component includes an electrostatic correction element disposed in the magnetic field / objective lens.

18. The multi-beam particle system as described in claim 13, The multi-beam particle system includes a multipole corrector and the second setting member is configured to cause modification control of the multipole corrector.

19. The multi-beam particle system as described in any of the preceding claims, The multi-beam particle system further includes an intermediate image plane and a telecentric correction component, particularly an additional field lens, in the first particle optical beam path. The telecentric correction component is disposed between the multi-beam generator and the intermediate image plane. The controller is configured to control the telecentric correction component so that the input telecentricity of the first separate particle beam changes in the intermediate image plane.

20. The multi-beam particle system as claimed in any of the preceding claims, configured for the first individual particle beam to be incident telecentrically onto the object plane.

21. The multi-beam particle system as described in any of the preceding claims, further comprising: The detection system has multiple detection zones that form a third field; A second particle optical unit having a second particle optical beam path, configured to image a second individual particle beam emitted from an incident position in the second field onto a third field in the detection region of the detection system; and A beam splitter is disposed in the first particle optical beam path between the aperture configuration and the objective lens, and in the second particle optical beam path between the objective lens and the detection system. The second separate particle beam also passes through this objective lens.

22. A method for operating a multi-beam particle system, particularly a multi-beam particle system as described in any of the preceding claims, the method comprising the following steps: (a) Provides a multi-beam particle system having a first crossover region of charged particle beams in the illumination beam path in the upper focal plane of the objective lens; and (b) Significantly increase the kinetic energy of the first individual particle beam in the cross region in segments, with the aim of significantly reducing the Coulomb interaction between the first individual charged particle beams.

23. The method of claim 22, further comprising the following steps: (c) Modify the maximum kinetic energy of the first separate particle beam in the intersection region, thereby modifying at least one imaging parameter of the multi-beam particle system when the first separate particle beam is incident on the object plane; and (d) Correct at least one modified imaging parameter.

24. A computer program product having program code for performing the method as described in any one of claims 22 to 23.

Images