Computer-implemented method and device for processing a sample with a nanomanipulator

Abstract

Computer-implemented method for processing a sample (102) with a nanomanipulator (104) comprising a measuring tip (106) for processing the sample (102) and a positioning unit (110) for moving the measuring tip (106), wherein the sample (102) is arranged on a sample stage (120), and an x-direction (x) and a y-direction (y) of the nanomanipulator (104) are each arranged parallel to a principal extension plane (E) of the sample (102) and / or the sample stage (120) and perpendicular to each other, comprising the steps: 1a) Controlling (S1) the positioning unit (110) to move the measuring tip (106) in the y-direction (y) such that an apex (168) of the measuring tip (106) is in contact with a surface (138, 172) of a test area (176) of the sample stage (120) or the sample (102) and the measuring tip (106) leaves a first trace (178) on the surface (138, 172), 1b) Controlling (S4) the positioning unit (110) to move the measuring tip (106) in the x-direction (x) so that the apex (168) of the measuring tip (106) is in contact with the surface (138, 172) and the measuring tip (106) leaves a second track (182) on the surface (138, 172), 1c) Controlling (S2, S5) an image acquisition device (128) to capture at least one image (260, 260', 260") of the test area (176) in which the first and second tracks (178, 182) are at least partially captured, and 1d) Determining (S3, S6) an x-position (x1, x1') of the apex (168) of the measuring tip (106) with respect to the x-direction based on the first track (178) captured in the at least one image (260') and determining a y-position (y1, y1') of the apex (168) of the measuring tip (106) with respect to the y-direction based on the second track (182) captured in the at least one image (260").

Description

[0001] The present invention relates to a computer-implemented method and a device for processing a sample with a nanomanipulator.

[0002] Microlithography is used to manufacture microstructured components, such as integrated circuits. The microlithography process is carried out using a lithography system, which includes an illumination system and a projection system. The image of a mask (reticule) illuminated by the illumination system is projected by the projection system onto a substrate, such as a silicon wafer, coated with a photosensitive layer (photoresist) and positioned in the image plane of the projection system. This transfers the mask structure onto the photosensitive coating of the substrate.

[0003] The mask (i.e., lithography mask) is used for a large number of exposures, which is why it is crucial that the mask is free of defects and contaminants. Therefore, lithography masks undergo extensive inspection for defects and contaminants. Attempts are then made to repair any defects found or to remove the contaminants. These defects and contaminants can be extremely small, ranging in size from a few nanometers. Therefore, devices with very high spatial resolution are required to remove them.

[0004] The contaminants include, for example, minute particles that have settled on the mask from the environment. Such contamination occurs more frequently, for instance, when the mask is transferred between different processing devices. The particles are of various types and have different sizes and / or shapes.

[0005] These particles can be, for example, metal particles, especially tin, but ceramic particles, polymer particles, and other carbon compounds can also be present. The particles are typically adsorbed onto the mask surface, meaning that there are no strong chemical bonds, such as atomic bonds, between the particle material and the mask surface.

[0006] A particle will leave the mask surface if the attractive forces applied to remove the particle (e.g., Coulomb forces and van der Waals forces) are greater than the attractive forces (e.g., Coulomb forces and van der Waals forces) on the mask surface. Depending on the type of interaction between the particle and the mask surface, activation energy may be required to break the existing bond with the mask surface.

[0007] Processing devices are known that allow for the targeted removal of individual particles from a surface. Nanomanipulators, such as atomic force microscopes, are used for this purpose. A particle is picked up by a measuring tip (measuring and manipulator tip) of the nanomanipulator and removed from the mask surface, adhering to the measuring tip. Particle removal is typically supported by imaging techniques (e.g., image acquisition using a scanning electron microscope and / or a scanning ion microscope) and requires manipulation by a user on a nanometer scale. Small user errors can easily lead to damage or destruction of the nanomanipulator's measuring tip or the sample. Furthermore, the process demands a high level of user attention, which can lead to fatigue and an increased risk of user errors.

[0008] Furthermore, sample processing, particularly particle removal, is complicated by the fact that the exact position of the probe tip's apex is unknown. The probe tip's apex is, in particular, the point and / or region of the probe tip that first comes into contact with the sample and / or a particle on the sample when the probe tip is approached. The actual apex of the probe tip is generally not visible in an image (e.g., a scanning electron microscope image and / or scanning ion microscope image) of the sample with the probe tip, so a lateral position of the apex cannot be derived from such an image alone. Moreover, the exact vertical position of the probe tip's apex (i.e., its distance from the sample) is also usually unknown due to the deflection of a boom to which the probe tip is attached.

[0009] Further scanning probe microscopes are from US 2018 / 0 267 081 A1, DE 10 2013 106 816 A1, Liang et al. 2019 (S. Liang et al.: “Atomic force microscope tip localization and tracking through deep learning based vision inside an electron microscope”, 2019 IEEE / RSJ International Conference on Intelligent Robots and Systems (IROS), Macau, China, 2019, pp. 2435-2440, doi: 10.1109 / IROS40897. 2019.8968567) and DE 10 2017 211 957 A1.

[0010] Against this background, one object of the present invention is to improve the processing of a sample with a nanomanipulator.

[0011] Accordingly, a computer-implemented method for processing a sample with a nanomanipulator is proposed. The nanomanipulator has a measuring tip for processing the sample and a positioning unit for moving the measuring tip. Furthermore, the sample is arranged on a sample stage. An x-direction and a y-direction of the nanomanipulator are each parallel to a principal extension plane of the sample and / or the sample stage and perpendicular to each other. The method comprises the following steps: 1a) Controlling the positioning unit to move the measuring tip in the y-direction, so that an apex of the measuring tip is in contact with a surface of a test area of ​​the sample table or the sample and the measuring tip leaves a first trace on the surface, 1b) Controlling the positioning unit to move the measuring tip in the x-direction so that the apex of the measuring tip is in contact with the surface and the measuring tip leaves a second track on the surface, 1c) Controlling an image capture device to capture at least one image of the test area in which the first and second tracks are at least partially captured, and 1d) Determining an x-position of the apex of the measuring tip with respect to the x-direction based on the first track captured in the at least one image and determining a y-position of the apex of the measuring tip with respect to the y-direction based on the second track captured in the at least one image.

[0012] This method allows the x- and y-position of the actual apex of the measuring tip to be determined even if only the apparent apex of the measuring tip is visible in the captured and received image. The actual apex of the measuring tip may not be visible in the image, in particular, because it is obscured with respect to a line of sight of the image acquisition device.

[0013] The apex of the measuring tip is, in particular, the point and / or region of the measuring tip that first comes into contact with the sample and / or a particle on the sample when the measuring tip approaches. The apex of the measuring tip is, for example, the lowest point and / or region of the measuring tip with respect to a z-direction of the nanomanipulator. Specifically, the measuring tip of the nanomanipulator is configured to touch a surface of the sample at its apex. The z-direction of the nanomanipulator is, in particular, perpendicular to the x- and y-directions. The z-direction of the nanomanipulator corresponds, in particular, to a vertical or gravitational direction of the nanomanipulator.

[0014] The x and y directions of the nanomanipulator are, in particular, arbitrary directions that are each parallel to the principal extension plane of the sample and / or the sample stage (e.g., a surface of the sample stage for arranging the sample) and perpendicular to each other.

[0015] The x, y and z directions of the nanomanipulator can, for example, correspond to the x, y and z directions of the positioning unit of the nanomanipulator.

[0016] The sample is, for example, a lithography mask with structures (e.g., absorber structures). These structures have, for example, a feature size in the range of 10 nm to 10 µm. The structures are arranged, for example, in a structural pattern for manufacturing a specific type of semiconductor chip. The sample could be, for example, a transmissive lithography mask for DUV lithography (DUV: "deep ultraviolet," working light wavelengths in the range of 30–250 nm) or a reflective lithography mask for EUV lithography (EUV: "extreme ultraviolet," working light wavelengths in the range of 1–30 nm, especially 13.5 nm).

[0017] The sample can also be a microelectronic component, such as an integrated circuit, in particular a CPU (CPU: "central processing unit"), GPU (GPU: "graphics processing unit"), RAM (RAM: "random access memory"), flash memory and the like.

[0018] The nanomanipulator and / or a higher-level device comprising the nanomanipulator includes, for example, a sample stage assembly with a holder, a sample stage movably mounted on the holder for arranging the sample, and a further positioning unit for moving the sample stage relative to the holder. The sample stage can be moved, for example, in the x and y directions (i.e., laterally) and / or in the z direction (vertical or gravitational direction) using the further positioning unit. The sample stage can also be rotatably mounted on the holder, for example, so that it can be rotated about the x, y, and / or z directions using the further positioning unit. The sample stage particularly includes a surface for arranging the sample.

[0019] The measuring tip is, in particular, a tip that is designed for measuring and manipulating (measuring and manipulator tip).

[0020] The nanomanipulator, for example, has a cantilever to which the measuring tip is arranged and / or attached. The cantilever and the measuring tip can also be monolithic. The cantilever is subsequently referred to as the "cantilever." The measuring tip has, for example, a length in the range of 0.5 µm to 1 mm and a diameter in the range of 20 nm to 1 µm. In particular, the measuring tip can taper towards its free end.

[0021] The measuring tip consists, for example, of a material containing carbon, silicon, one or more precious metals, tungsten, platinum, iridium, and / or a platinum-iridium alloy. This tip allows for the precise targeting of individual positions on the sample surface, particularly when the sample exhibits structures with a high aspect ratio. The aspect ratio can be defined, for example, as the ratio of a structure's width to its height. An example of a structure with a high aspect ratio of 1:10 is a narrow, deep trench that is, for instance, 1 µm wide and 10 µm deep.

[0022] For example, the hardness of the measuring tip indicates a Mohs hardness of 7 or greater, 8 or greater, and / or 9 or greater. Mohs hardness is a measure of hardness based on the Mohs scale developed by Friedrich Mohs.

[0023] The nanomanipulator includes a positioning unit to which the cantilever is movably attached. This unit allows the cantilever to be moved in the three spatial directions x, y, and z relative to the positioning unit (translational movement in the three spatial directions). These three spatial directions define a three-dimensional space. The positioning unit is attached, for example, to a housing of the nanomanipulator and / or to a higher-level device that incorporates the nanomanipulator.

[0024] The cantilever has a distinctly elongated shape with a longitudinal axis. Furthermore, the cantilever is movably attached to the positioning unit at one end relative to its longitudinal axis. Using the positioning unit, the position of the cantilever's first end (also called the base or foot end) can be set in the three spatial directions x, y, and z. Additionally, the cantilever has a measuring tip at its second end (free end) relative to its longitudinal axis.

[0025] When the probe tip approaches the sample surface, an interaction occurs between the tip and the surface. This interaction can be based on direct contact, van der Waals interaction, or other physical interactions, as well as combinations thereof. By scanning (rasterizing) the sample surface with the probe tip, a three-dimensional image of the surface can be acquired. For example, at each scan position, the distance between the probe tip and the sample surface is kept constant using a closed-loop control system, and the position of a microactuator for adjusting this distance is monitored.

[0026] A particle is, in particular, a foreign body, such as dust or dirt, that has settled on the sample surface. It can also be said that the particle is adsorbed onto the sample surface. Particles adsorbed onto the sample surface can have different properties and shapes. For example, the particle size ranges from 3 nm to 50 µm.

[0027] Such a particle can be located on the sample surface using optical analysis methods and precisely targeted with the measuring tip. To pick up the particle with the measuring tip, it must first be detached from the sample surface. This means that the forces acting between the sample surface and the particle must be overcome. The strength of the particle's adhesion to the sample surface depends on both the particle's shape and properties, as well as the properties of the sample surface, particularly its surface energy. The higher the surface energy, the stronger the particle's adsorption.

[0028] To pick up the particle with the measuring tip, the measuring tip is brought into contact with the particle. If the attractive forces of the measuring tip are greater than the attractive forces of the sample surface, the particle will detach from the sample surface and can be picked up by the measuring tip.

[0029] It can be helpful to first move the particle across the sample surface using the probe tip to break any existing bonds between the particle and the sample surface. This can, for example, reduce the particle's binding energy to the surface. Furthermore, this can increase the contact area between the probe tip and the particle. A larger contact area increases the likelihood that the particle will adhere to the probe tip and detach from the sample surface.

[0030] Once the particle has been picked up by the measuring tip, it must be removed from the tip in order to continue using the tip. The particle should be placed either in a position on the sample surface where it will not interfere with the process or on a separate storage unit.

[0031] The nanomanipulator can be part of a larger device for processing the sample, which includes the nanomanipulator.

[0032] The overall device for processing the sample can, for example, also include a control device for carrying out the proposed procedure. The control device, for example, controls the positioning unit in step 1a) to move the measuring tip in the y-direction to inscribe the first track in the y-direction. The control device, for example, controls the positioning unit in step 1b) to move the measuring tip in the x-direction to inscribe the second track in the x-direction. The control device, for example, controls the image acquisition device in step 1c) to acquire at least one image of the test area. The control device receives the acquired images from the image acquisition device. In step 1d), the control device determines the x-position and y-position of the apex of the measuring tip accordingly, based on the first and second tracks captured in the images.

[0033] Furthermore, the higher-level device for processing the sample may also include, for example, an image acquisition device, such as a scanning electron microscope and / or a scanning ion microscope, for capturing images of the sample.

[0034] The test area of ​​the sample stage or the sample itself, into whose material the first and second tracks are inscribed, is specifically an area of ​​the sample stage or sample where the tracks do not interfere with the process. For example, a test area of ​​the sample is an area that is not used when the sample is employed (e.g., as a mask in lithography).

[0035] For example, the sample may have a substrate, a capping layer, and / or structures (e.g., absorber structures) made of a material with a first hardness. Furthermore, the test area of ​​the sample stage or the sample itself may have a material with a second hardness, which is lower than the first hardness. The first and second hardnesses each represent a mechanical resistance that the respective material offers to the mechanical penetration of the apex of the measuring tip.

[0036] The first and second tracks are, for example, marks inscribed into a material of the test area by the apex of the measuring tip, such as embossed marks and / or scratch marks. The first and second tracks each exhibit, for example, depressions relative to a surface of the test area prior to the application of the first and second tracks. The first track is specifically aligned parallel to the y-direction, and the second track is specifically aligned parallel to the x-direction.

[0037] Steps 1c) and 1d) are initially performed only for the first track, specifically after step 1a). In step 1c), the image acquisition device is controlled to capture at least one image of the test area in which the first track is at least partially captured. After step 1b), steps 1c) and 1d) are performed again, this time only for the second track. In step 1c), the image acquisition device is controlled to capture at least one image of the test area in which the second track is at least partially captured.

[0038] In one configuration, the first and second tracks can be generated on the surface of the test area in such a way that they are spaced apart and do not touch each other. In other words, the first and second tracks are not connected in this case.

[0039] In a second arrangement variant, the first and second tracks can also be generated on the surface of the test area in such a way that the first and second tracks intersect (e.g., intersect at a right angle).

[0040] In a third arrangement variant, the first and second tracks can be, for example, subsections of a continuous overall track, in addition to the two tracks intersecting, or instead of the two tracks intersecting.

[0041] Furthermore, in one, several and / or all of the three mentioned arrangement variants, the apex of the measuring tip can be moved away from the surface of the test area between the generation of the first track and the generation of the second track.

[0042] The image acquisition device is, for example, a scanning electron microscope and / or a scanning ion microscope. Furthermore, the x-position and y-position of the apex of the measuring tip are determined in this case based on at least one scanning electron microscope image or scanning ion microscope image received from the scanning electron microscope or scanning ion microscope.

[0043] According to one embodiment, the nanomanipulator has a boom with a foot end and a free end, wherein the measuring tip is arranged at the free end of the boom and the boom is movably attached to the positioning unit at its foot end. Furthermore, the positioning unit is controlled to move the foot end of the boom, thus moving the measuring tip.

[0044] The positioning unit is controlled, for example, by the control device. The positioning unit is specifically used to move the foot end of the boom, so that the measuring tip moves along with it.

[0045] According to another embodiment, the x-position and y-position of the apex of the measuring tip are determined by adjusting a respective straight line to the first and second track captured in the image.

[0046] The fitting of the respective line is performed, for example, by the control device. This fitting is achieved, for instance, through a computer-aided approximation method, in which a respective linear function is adapted to the first or second track captured in the image.

[0047] According to a further embodiment, the measuring tip is at least partially captured in the at least one image, wherein a lateral position of an apparent apex of the measuring tip in the at least one image differs from a lateral position of an actual apex of the measuring tip in the at least one image, and the lateral position of the actual apex of the measuring tip relative to the lateral position of the apparent apex of the measuring tip in the at least one image is determined.

[0048] By knowing the lateral position (i.e., the x and y position) of the actual apex of the measuring tip relative to the lateral position (i.e., the x and y position) of the apparent apex of the measuring tip in at least one image, an offset between the x and y position of the actual (but not visible in the image) apex of the measuring tip and the x and y position of the apparent (visible in the image) apex of the measuring tip can be determined. Since this x and y offset typically does not change for a given measuring tip, the x and y position of the actual apex of the measuring tip can be easily determined using the calculated x and y offset based on any image of the measuring tip, especially one taken along the same line of sight.

[0049] Precise knowledge of the x and y positions of the actual apex of the probe tip used to process a sample enables more accurate sample processing. For example, this allows for more targeted and effective removal of particles from the sample using the probe tip.

[0050] The image is, in particular, a two-dimensional image.

[0051] According to another embodiment, the lateral position of the actual apex of the measuring tip is determined relative to a lateral position of the foot end of the boom.

[0052] This allows the contact point of the actual apex of the measuring tip with the surface of the sample to be determined at any time, provided the measuring tip is visible in the image.

[0053] According to a further embodiment, the nanomanipulator has a deflection detection device for detecting a z-deflection of the free end of the boom in a z-direction that is arranged perpendicular to the x- and y-directions and points away from the sample. The method also includes: 6a) Controlling the positioning unit to move the foot end of the boom in a negative z-direction, so that a z-distance with respect to the z-direction between the foot end of the boom and the sample is reduced and the measuring tip is brought closer to the sample in a test area of ​​the sample, 6b) repeated reception, from the deflection detection device, of the magnitude of the z-deflection of the free end of the boom as a function of the z-distance of the foot end of the boom from the sample, 6c) Determining an approximation curve that shows the extent of the z-deflection of the free end of the boom as a function of the z-distance of the foot end of the boom from the sample, 6d) Receiving at least one image of the sample in which the test area is at least partially captured, 6e) Determine, based on the at least one image received, whether the sample is damaged in the test area, and 6f) Storing a minimum z-deflection and / or a minimum z-distance of the approach curve as a safe z-deflection of the free end of the boom or as a safe z-distance of the foot end of the boom from the sample if it is determined that the sample is not damaged in the test area.

[0054] This allows a safe deflection of the free end of the boom and thus a safe minimum distance of the apex of the measuring tip from the sample in the z-direction to be determined, even though the exact z-position of the apex of the measuring tip is usually unknown.

[0055] Here, the nanomanipulator is used in particular as a force sensor and force distance spectrocopy is performed.

[0056] The x, y, and z positions of the boom's foot end relative to the positioning unit are precisely known. Specifically, these positions can be set by controlling the positioning unit. Consequently, current values ​​of the x, y, and z positions relative to the boom's foot end can be provided by the positioning unit. In particular, the z position of the boom's foot end can be provided by the positioning unit and is therefore precisely known. However, the exact z position of the measuring tip's apex may remain unknown due to the changing deflection of the boom's free end and potential bending of the measuring tip relative to the boom.

[0057] The deflection of the cantilever's free end in the z-direction is caused by forces acting between the probe tip and the sample. This deflection is also proportional to the cantilever's spring constant. Specifically, the cantilever bends to varying degrees during scanning of the sample, depending on the forces acting between the probe tip and the sample. The extent of this deflection can be measured using a deflection detection device. For example, the nanomanipulator and / or a higher-level device comprising the nanomanipulator incorporates such a deflection detection device.

[0058] The deflection detection device is, for example, a light pointer device. The light pointer device comprises, for example, a laser source and a position-sensitive photodetector. A laser beam emitted by the laser source is directed at the free end of the cantilever and, in an undeflected position of the cantilever, reflected to the center of the position-sensitive photodetector. The photodetector is divided, for example, into four regions: "top left," "top right," "bottom left," and "bottom right." When the deflection of the cantilever changes, the reflected laser spot moves across the photodetector like a light pointer. By measuring the intensities in the four regions of the photodetector, vertical and horizontal deflection signals can be determined, which are proportional to the normal force and lateral forces, respectively.

[0059] Furthermore, interaction between the measuring tip and the sample (e.g., lateral movement of the measuring tip upon contact with the sample) can cause bending (i.e., elastic deformation) of the measuring tip relative to the arm. The extent of this bending of the measuring tip relative to the arm can be determined using image processing of acquired images (e.g., scanning electron microscope images, scanning ion microscope images) of the measuring tip.

[0060] In step 6a), for example, the x and y position of the foot end of the boom is kept constant.

[0061] The test area of ​​the sample is specifically an area where damage to the sample does not cause problems. For example, the test area of ​​the sample is an area that is not used when the sample is actually used (e.g., as a mask in lithography).

[0062] Damage to the test area, for example, would be indicated by indented material in the test area.

[0063] The safe deflection is stored, for example, in a storage device of the nanomanipulator.

[0064] For example, the procedure before controlling the positioning unit to move the measuring tip in the negative z-direction includes: Controlling the positioning unit to move the measuring tip laterally (i.e., in the x and / or y direction) into the test area of ​​the sample, wherein, during the subsequent control of the positioning unit to move the measuring tip in the negative z-direction, the x and y position of the foot end of the boom are kept constant.

[0065] For example, after determining the approach curve, the procedure involves controlling the positioning unit to move the measuring tip in the positive z-direction by a predetermined z-distance (retracting the measuring tip from the sample by the predetermined z-distance).

[0066] Steps 6a) to 6f) are performed, for example, by the control device.

[0067] In embodiments, in step 6a), the positioning unit is controlled to move the base of the boom in the negative z-direction, so that the measuring tip is brought close to the sample within the test area up to a certain z-end distance relative to the z-direction. Furthermore, several approach curves are determined based on different z-end distances of the measuring tip to the sample relative to the z-direction and offset x- and / or y-positions of the measuring tip relative to each other. For each determined approach curve, at least one image of the sample is also received in which the test area is at least partially captured. Then, for each received image, it is determined whether the sample is damaged in the test area.Furthermore, a minimum deflection (and thus a minimum distance) of the approach curve, which is based on the smallest z-end distance of the measuring tip to the sample, for which it is determined based on the corresponding image that the sample is not damaged in the test area, is stored as a safe deflection of the free end of the boom.

[0068] According to another embodiment: Several approximation curves are determined based on several different test areas, which differ from each other by the type of material in the test area. At least one image will be received in which the multiple test areas are at least partially captured. For each determined approximation curve, based on the at least one received image, it is determined whether the sample is damaged in the respective test area, and A minimum z-deflection and / or a minimum z-distance of the respective approach curve is stored as a safe z-deflection of the free end of the boom or as a safe z-distance of the foot end of the boom from the sample, depending on the corresponding material of the respective test area, if it is determined that the sample is not damaged in the respective test area.

[0069] For example, each determined approximation curve is assigned at least one received image in which the respective test area is at least partially captured. Alternatively, two, more, or all test areas are depicted within the image section of a single image.

[0070] The different test areas, which differ from each other by the type of material used in the test area, include, for example, a material corresponding to a material of structures (e.g. absorber structures) of the sample, a material corresponding to a material of a substrate of the sample, and a material corresponding to a capping layer, covering layer and / or protective layer (e.g., covering layer of an EUV mask) of the sample.

[0071] According to a further embodiment, the nanomanipulator preferably comprises a sample stage assembly with a holder, a sample stage movably arranged on the holder, and a further positioning unit for moving the sample stage relative to the holder. The method also includes: 8a) Controlling the positioning unit to move the measuring tip in the negative z-direction so that the measuring tip is brought into contact with the sample, and 8b) Controlling the positioning unit and / or the further positioning unit to move the measuring tip or the sample arranged on the sample table, so that the measuring tip and the sample are moved to a predetermined distance from each other.

[0072] This allows the measuring tip to be moved away from the sample by a predetermined distance, starting from contact with the sample (e.g., with a surface of the sample). Advantageously, a predetermined fixed working distance between the measuring tip and the sample (i.e., in the z-direction) can be applied. This fixed, predetermined working distance improves the reproducibility of images (e.g., with a scanning electron microscope and / or a scanning ion microscope) of the sample in which the measuring tip is at least partially captured. This, in turn, improves image-monitored processing. Image-monitored processing includes, for example, manipulation processes using the measuring tip (e.g., displacement of particles on the sample and / or removal of particles from the sample) and / or particle beam-induced processes (e.g.,...Electron beam-induced processes and / or ion beam-induced processes), such as etching processes and depositional processes.

[0073] Furthermore, the predetermined distance can be chosen such that drift of the measuring tip relative to the sample does not lead to damage to the sample, e.g., to its structure. Drift of the measuring tip relative to the sample can occur due to thermal drift (e.g., heating of the measuring tip and / or the cantilever) or charging of the sample surface due to processing with a particle beam (e.g., imaging with a scanning electron microscope). This increases the force between the measuring tip and the sample, leading to drift. A so-called "creep" of the measuring tip when approaching a specific position on the sample is also known.

[0074] The predetermined distance between the measuring tip and the sample can be set in one variant by controlling the positioning unit to move the base of the boom, and thus the measuring tip, away from the sample. Alternatively, in a second variant, the predetermined distance between the measuring tip and the sample can be set by controlling the other positioning unit of the sample table assembly to move the sample table, and thus the sample arranged on the sample table, away from the measuring tip in the negative z-direction.

[0075] Steps 8a) and 8b) are performed, for example, by the control device.

[0076] In embodiments, the nanomanipulator includes a deflection detection device (e.g., a light pointer device) for detecting a deflection of the free end of the boom in a z-direction, which is arranged perpendicular to the x- and y-directions. Furthermore, in step 8a), the deflection detection device receives the magnitude of the deflection of the free end of the boom in the z-direction. Also in step 8a), the positioning unit is controlled to move the base end of the boom in the negative z-direction, so that the measuring tip is brought close to the sample until the received magnitude of the deflection corresponds to a predetermined magnitude of deflection. The predetermined magnitude of deflection corresponds, in particular, to contact between the measuring tip and the sample (e.g., the surface of the sample).

[0077] According to another embodiment, the method has: 9a) Providing a remote trajectory for removing a particle placed on the sample, wherein the remote trajectory lies in an xy-plane spanned by the x and y directions and intersects an xy-position of the particle, 9b) Controlling the positioning unit to position the measuring tip in relation to the z-direction at a first predetermined z-distance from the sample, 9c) Controlling the positioning unit to move the measuring tip laterally along the determined distance trajectory and at the first predetermined z-distance to the sample, 9d) Controlling the positioning unit to move the measuring tip away from the sample in the positive z-direction, 9e) Determine whether the particle adheres to the measuring tip, and 9f) Repeat steps 9b) to 9e) for one or more further predetermined z-distances, which are progressively smaller than the first predetermined z-distance, until it is determined that the particle adheres to the measuring tip, where steps 9b) to 9f) are executed fully automatically.

[0078] Removing particles from a sample requires manipulations on the nanometer scale. The proposed particle removal process allows for fully automated removal of a particle from the sample, i.e., without user intervention. Specifically, a predetermined removal trajectory is employed, which is a path and / or trajectory along which the probe tip is moved to engage the particle. The removal trajectory can also be described as an access path for the probe tip to reach the particle. In particular, the predetermined removal trajectory (which is specifically arranged in an xy-plane) can be traversed fully automatically by the probe tip at various z-distances from the sample. The z-distance between the probe tip and the sample is progressively and incrementally reduced. This allows the particle to be removed as close as possible to the sample (i.e., as close as possible to the sample's surface).The aim is to approach the sample (as close as possible to the sample surface) with the measuring tip without damaging the measuring tip and / or the sample. In particular, gradually reducing the z-distance between the measuring tip and the sample has the advantage of preventing physical contact between the measuring tip and / or the sample as much as possible, thus avoiding damage to the measuring tip and / or the sample.

[0079] For example, a user simply needs to start the particle removal process – e.g., using a human-machine interface (HMI). The HMI might include a keyboard, mouse pointer, joystick, game controller, touchscreen, or similar device. Once the particle removal process is started, steps 9b) to 9f) are executed fully automatically. Specifically, once the particle removal process is started, the measuring tip is automatically moved at various z-distances, first laterally along the removal trajectory (step 9c) and then in the positive z-direction away from the sample (step 9d), until the particle adheres to the measuring tip.

[0080] The first predetermined z-distance is, for example, 50 nm, 40 nm, or 30 nm. The one or more subsequent predetermined z-distances are, for example, 5 nm, 10 nm, or 15 nm smaller than the immediately preceding z-distance (i.e., the first or subsequent predetermined z-distance). By way of example only, the first predetermined z-distance is 50 nm, a second predetermined z-distance is 40 nm, a third predetermined z-distance is 30 nm, a fourth predetermined z-distance is 20 nm, and a fifth predetermined z-distance is 10 nm.

[0081] If, in step 9e), it is already determined for the first z-distance that the particle adheres to the measuring tip, step 9f) is not performed.

[0082] Lateral movement of the measuring tip specifically refers to moving the measuring tip in the x- and / or y-direction (in other words, in the xy-plane). For example, the measuring tip is moved exclusively in the x-direction, exclusively in the y-direction, or in both the x- and y-directions simultaneously.

[0083] The x and y positions of the particle are corresponding positions with respect to the x and y directions.

[0084] The distance trajectory is, for example, a linear distance trajectory.

[0085] Steps 9a) to 9f) are performed, for example, by the control device.

[0086] In embodiments, determining the distance trajectory involves: Receiving an image of at least a part of the sample, wherein the image captures the particle arranged on the sample surface, Determining the distance trajectory for removing the particle based on the received image.

[0087] In embodiments, a linear removal trajectory for the particle is determined such that the removal trajectory intersects the particle, a length of the removal trajectory is longer than a size of the particle, and the removal trajectory is free of structures of the sample.

[0088] In embodiments, a linear removal trajectory for the particle is determined such that the removal trajectory extends beyond the particle on one side by twice the particle size. Additionally or instead, the removal trajectory is determined, for example, such that it extends beyond the particle on the other side by one and a half times the diameter of the measuring tip.

[0089] In embodiments, the method includes: Automatic monitoring of one or more parameters, such as a deflection of the free end of the boom in the z-direction, a rotation of the free end of the boom about the x-direction, and / or a bending of the measuring tip relative to the boom. Furthermore, the positioning unit is controlled to stop a lateral movement of the measuring tip and / or to retract the measuring tip relative to the sample (i.e., in the positive z-direction) when it is determined that the current state of one or more parameters lies outside a permissible range.

[0090] In step 9b), for example, the positioning unit is controlled such that the measuring tip (i.e., the apex of the measuring tip) is positioned at a point on the distance trajectory with respect to the x and y directions.

[0091] According to another embodiment, step 9c) has:

[0092] Controlling the positioning unit to laterally move the measuring tip along the determined distance trajectory in steps of a first predetermined lateral distance and preferably in steps of one or more further predetermined lateral distances, which are increasingly larger than the first predetermined lateral distance.

[0093] By increasing the step size during the lateral movement of the measuring tip, a progressively greater force can be applied laterally to attempt to dislodge a particle. However, since this simultaneously carries the risk of damaging the sample and / or the measuring tip, the lateral distance is increased only gradually. This ensures that only as much force as is necessary to detach the particle is applied.

[0094] The first predetermined lateral distance is, for example, 10 nm, 20 nm, or 30 nm. One or more further predetermined lateral distances are, for example, 30 nm, 40 nm, 50 nm, 60 nm, and / or 70 nm.

[0095] According to another embodiment, the method has: 9a') Controlling the positioning unit to position the measuring tip on a surface of the sample adjacent to a particle on the surface, wherein a foot point of the boom is located at a first predetermined z-distance from the sample with respect to the z-direction, 9b') Controlling the positioning unit to move the measuring tip laterally to detach the particle from the surface, 9c') Determine whether the particle has moved on the surface, and 9d') Repeat steps 9a') to 9c') for one or more further predetermined z-distances between the base of the boom and the sample, which are progressively smaller than the first predetermined z-distance, until it is determined that the particle has moved on the surface, where steps 9a') to 9d') are executed fully automatically.

[0096] By repeating steps 9a') to 9c') for increasingly smaller z-distances between the base of the boom and the sample, a progressively increasing force is exerted on the measuring tip and thus on the particle until the particle has detached from the surface. This ensures that only the necessary amount of force is applied to detach the particle from the surface. At the same time, unnecessarily high force is avoided, thereby preventing damage to the measuring tip and / or the sample.

[0097] According to another embodiment, the method has: 12a) Controlling the positioning unit to move the measuring tip laterally towards a particle arranged on the sample, 12b) Determine whether the particle adheres to the measuring tip, and 12c) Controlling the positioning unit to move the measuring tip away from the sample in a positive z-direction and / or to move the measuring tip along a curved trajectory which, in the area of ​​the particle, bends from an initial lateral movement into a movement in a positive z-direction when it is determined that the particle is adhering to the measuring tip, where steps 12a) to 12c) are carried out fully automatically.

[0098] This allows the move and lift movement of the measuring tip, as may be necessary for picking up a particle from the sample surface, to be performed fully automatically. In particular, it can be determined fully automatically whether the particle is adhering to the measuring tip. Furthermore, if the particle is confirmed to be adhering to the measuring tip, the measuring tip is automatically moved away from the sample in the positive z-direction (step 12c), thus lifting the particle from the sample surface.

[0099] Steps 12a) and 12b) are executed simultaneously and / or repeatedly, for example. Steps 12a) to 12c) are executed by the control device, for example.

[0100] In step 12a), the positioning unit is controlled, in particular, for the linear lateral movement of the measuring tip in the direction of the particle arranged on the sample and / or for moving the measuring tip along the curved trajectory.

[0101] According to another embodiment, the method has: Controlling the positioning unit to move the measuring tip in a lateral direction and / or in a positive z-direction to pick up a particle arranged on the sample with the measuring tip, Determine whether the particle adheres to the measuring tip based on: a magnitude of lateral deflection of the boom received by a deflection detection device, several received images of at least part of the sample in which the particle is detected, and a change in the brightness of the particle and / or contrast of the particle relative to the measuring tip in the several images, determined by means of image processing, several images of at least part of the sample received by an image acquisition device, in which the particle is detected, and a migration of the particle from a fixed focus of the image acquisition device determined by means of image processing of the several images, and / or Information received from an image acquisition device, which takes pictures of at least part of the sample in which the particle is detected, with an autofocus setting focused on the particle, about the extent of an automatic adjustment of the autofocus focused on the particle, which is greater than a predetermined threshold.

[0102] This allows the system to determine, according to one, several, or all of four different variants (first to fourth variants), whether the particle is adhering to the measuring tip. In particular, this allows, for example, a fully automated determination of whether the particle is adhering to the measuring tip.

[0103] For example, the particle can be moved laterally using the measuring tip until an indication of adhesion is detected according to one or more of the first to fourth variants. The measuring tip can then be moved in the positive z-direction (i.e., raised), and it can be checked, using one or more of the first to fourth variants, whether the particle rises along with the measuring tip (i.e., remains adhered to the measuring tip) or not (i.e., detaches from the measuring tip).

[0104] For example, the control device receives the degree of deflection detected by the deflection detection device. For example, the control device receives one or more images captured by the image acquisition device. For example, the control device determines, according to one, several, or all of the four different variants, whether the particle is adhering to the measuring tip.

[0105] In the first variant, whether the particle is adhering to the measuring tip is determined based on the degree of lateral deflection of the boom received by the deflection detection device. The degree of lateral deflection of the boom can be determined, for example, based on the degree of twisting of the boom. For instance, it is determined that the measuring tip is in contact with the particle if the degree of lateral deflection of the boom is greater than a predetermined threshold.

[0106] In the second variant, whether the particle adheres to the measuring tip is determined based on a change in brightness and / or contrast of the particle in images (e.g., electron microscope images and / or ion microscope images). In the multiple images received of the sample, at least part of the measuring tip is captured in addition to the particle. The change in brightness of the particle is, for example, a change in the brightness of the particle relative to the brightness of the measuring tip in the images. The change in contrast of the particle is, for example, a change in the contrast between the particle and the measuring tip in the images. For example, the brightness of the particle increases when the particle adheres to the measuring tip compared to when the particle does not.

[0107] For example, when a particle adheres to the measuring tip, it becomes electrically charged, making the particle appear brighter in the image. Conversely, when the particle detaches from the measuring tip, it becomes darker again in the image.

[0108] In the third variant, based on the particle's migration from a fixed focus of the image acquisition device, it is determined that the particle adheres to the measuring tip and is thus lifted along with the measuring tip (moved in the positive z-direction). Specifically, the images are used to determine that the particle is initially located in a focus of the image acquisition device (i.e., the focus is set on the particle), and that in later images the particle is no longer in focus.

[0109] In the fourth variant, the particle images are captured with an autofocus setting focused on the particle. Furthermore, based on an automatic adjustment of the autofocus focused on the particle by more than the predetermined threshold, it is inferred that the particle's z-position has changed significantly, indicating that the particle was lifted along with the measuring tip (in the positive z-direction).

[0110] The fourth variant optionally determines whether the autofocus set for the particle changes in response to movement of the measuring tip in the positive z-direction. This movement of the measuring tip in the positive z-direction is determined, for example, using position data of the boom's base received by the positioning unit.

[0111] According to another embodiment, the nanomanipulator comprises a sample stage assembly with a holder, a sample stage laterally movable on the holder, and a further positioning unit for laterally moving the sample stage relative to the holder in the x and y directions. The method further comprises: 14a) Controlling the positioning unit to position the measuring tip in a lateral initial position preset in the positioning unit with respect to the x and y directions, 14b) Receiving at least one image of the sample in which a particle arranged on the sample is captured, 14c) Determine, based on image processing, a lateral position of the particle captured in the at least one image, and 14d) Controlling the further positioning unit to laterally move the sample table with the sample such that the lateral position of the particle corresponds to the initial lateral position of the measuring tip with respect to the x and y directions, and Steps 14a) to 14d) are executed fully automatically.

[0112] This allows the measuring tip to first be moved to its preset initial position. Furthermore, the particle to be processed can be positioned below the measuring tip, i.e., at the same x and y position as the measuring tip. This facilitates processing the particle with the measuring tip. For example, the measuring tip has only a small, limited lateral range (e.g., ±20 µm in the x and y directions) within which it can move. Therefore, it is advantageous to position the particle fully automatically below the measuring tip at the same x and y coordinates as the measuring tip, while simultaneously positioning the measuring tip in its original position. This provides sufficient space in the x and y directions around the particle to move the measuring tip in such a way that the particle can be picked up by the measuring tip.In particular, when several particles are arranged on the sample that are too far apart to be reached simply by moving the measuring tip, it is advantageous to automatically move the sample stage accordingly.

[0113] Positioning the particle fully automatically below the measuring tip at the same x and y coordinates as the measuring tip, while simultaneously positioning the measuring tip in its original position, is also advantageous because this places the particle within the field of view of the image acquisition device.

[0114] The initial position of the measuring tip, preset in the positioning unit with respect to the x and y directions, is, for example, a preset origin position of the measuring tip in the positioning unit. This initial position or origin position corresponds, for example, to the origin of the coordinate system of the positioning unit (x=0, y=0).

[0115] Steps 14a) to 14d) are performed, for example, by the control device.

[0116] In various embodiments, the method features: Controlling an image acquisition device to capture one or more initial images of at least a part of the sample in which the measuring tip is at least partially captured, Determine, based on image processing, a position of the measuring tip (lateral position, x and / or y position, e.g., position of the apparent apex of the measuring tip) in the one or more first images, and Controlling the image acquisition device to capture one or more further images of at least a part of the sample, in which the measuring tip captured in the first image(s) is positioned at a predetermined position in the image (e.g. in the center of the image).

[0117] This allows the measuring tip to be automatically held at a predetermined position in one or more subsequent images (e.g., in the center of an image) when repeatedly taking pictures (English: tip tracking).

[0118] For example, based on image processing of the first image(s), a lateral position (i.e., an x ​​and / or y position) of the measuring tip is determined.

[0119] For example, based on image processing of the first image(s), a position (e.g., lateral position or x- and / or y-position) of the apparent apex of the measuring tip is determined. Furthermore, the image acquisition device is controlled to capture one or more additional images of at least a portion of the sample, in which the apex of the measuring tip, captured in the first image(s), is positioned at a predetermined location within the image (e.g., in the center of the image).

[0120] According to another aspect, a computer-implemented method for processing a sample with a nanomanipulator is proposed. The nanomanipulator has a measuring tip for processing the sample and a positioning unit for moving the measuring tip. Furthermore, the sample is arranged on a sample stage. An x-direction and a y-direction of the nanomanipulator are each parallel to a principal extension plane of the sample and / or the sample stage and perpendicular to each other. The sample has a nanostructure on its surface for determining the actual apex of the measuring tip. The method comprises the following steps: 15a) Controlling the positioning unit to laterally move the measuring tip from lateral start coordinates to lateral end coordinates to scan the nanostructure and generate raster data, 15b) Determining nanostructure coordinates of a highest point of the nanostructure in the raster data, 15c) Determining a first lateral distance from the nanostructure coordinates to the lateral end coordinates, 15d) Taking at least one image of the sample in which the measuring tip and the nanostructure are at least partially captured, with the measuring tip located at the lateral end coordinates, 15e) Determining a second distance of an apparent apex of the measuring tip from the nanostructure, and 15f) Determining the position of the actual apex of the measuring tip based on the difference between the first and second distances.

[0121] This allows the position (e.g., x- and y-position) of the actual apex of the measuring tip to be determined even if only the apparent apex of the measuring tip is visible in the captured and received image. The actual apex of the measuring tip may not be visible in the image, in particular, because it is obscured with respect to a line of sight of the image acquisition device.

[0122] The nanostructure for determining the actual apex of the measuring tip has, for example, a lateral size of 30 nm or less, 20 nm or less, 10 nm or less and / or 5 nm or less.

[0123] The nanostructure for determining the actual apex of the measuring tip has, for example, a spherical, hemispherical, and / or spherical surface. Alternatively, the nanostructure for determining the actual apex of the measuring tip can also have a point, in particular a point that tapers away from the sample surface in one direction.

[0124] According to another aspect, a computer program product is proposed which includes instructions that, when the program is executed by at least one computer, cause it to execute the procedure described above.

[0125] A computer program product, such as a computer program tool, can be provided or delivered, for example, as a storage medium such as a memory card, USB stick, CD-ROM, DVD, or as a downloadable file from a server on a network and / or from a cloud-based source. This can be done, for example, over a wireless communication network by transmitting the corresponding file containing the computer program product or tool.

[0126] According to another aspect, a device for processing a sample is proposed. The device features: a nanomanipulator with a measuring tip for processing the sample and a positioning unit for moving the measuring tip, a sample stage for arranging the sample, wherein an x-direction and a y-direction of the nanomanipulator are each arranged parallel to a principal extension plane of the sample and / or the sample stage and perpendicular to each other, and a control device designed to perform the procedure described above.

[0127] The principal extension plane of the sample and / or the sample table is, for example, an xy-plane spanned by the x-direction and the y-direction.

[0128] The device for processing a sample includes, for example, a sample stage assembly with a holder, wherein the sample stage is movably mounted on the holder. The sample stage assembly also includes, for example, a further positioning unit for moving the sample stage relative to the holder. The sample stage can be moved, for example, in the x and y directions (i.e., laterally) and / or in the z direction (vertically) using the further positioning unit. The sample stage can also be rotatably mounted on the holder, for example, so that it can be rotated about the x, y, and / or z directions using the further positioning unit. The sample stage particularly includes a surface for arranging the sample.

[0129] The respective unit, for example, the control device, can be implemented in hardware and / or software. In a hardware implementation, the respective unit can be a device or part of a device, for example, a computer or a microprocessor. In a software implementation, the respective unit can be a computer program product, a function, a routine, part of program code, or an executable object.

[0130] The term "one" here is not necessarily to be understood as limiting to exactly one element. Rather, multiple elements, such as two, three, or more, may be included. Likewise, every other counter used here is not to be understood as limiting the number to precisely the stated number of elements. Instead, numerical deviations, both upward and downward, are possible unless otherwise specified. The numbering of features in the claims, such as 1a, 1b, 6a, 6b, etc., does not imply any order, neither within a single claim nor in the combination of several claims. For example, step 6b may precede step 6a unless otherwise specified.

[0131] The embodiments and features described for the method apply accordingly to the proposed device and vice versa.

[0132] Other possible implementations of the invention also include combinations of features or embodiments described previously or subsequently with regard to the exemplary embodiments, even if not explicitly mentioned. In such cases, the person skilled in the art will also add individual aspects as improvements or additions to the respective basic form of the invention.

[0133] Further advantageous embodiments and aspects of the invention are the subject of the dependent claims and the exemplary embodiments of the invention described below. The invention will be explained in more detail below with reference to preferred embodiments and the accompanying figures. Fig. Figure 1 shows a device for analyzing and / or processing a sample according to one embodiment; Fig. Figure 2 shows an enlarged section of the device. Fig. 1 together with a light pointer device according to one embodiment; Fig. Figure 3 shows a section of a section of a device made with the device. Fig. 1 sample to be processed according to one embodiment; Fig. 4 shows a cross-section of Fig. 3 along line IV-IV; Fig. Figure 5 shows an enlarged view of a measuring tip of the device. Fig. 1 according to one embodiment; Fig. Figure 6 shows a picture of a section of a sample and the measuring tip. Fig. 5 according to one embodiment; Fig. 7 shows a similar view Fig. 6, wherein the measuring tip has left a first trace in a test area of ​​the sample according to one embodiment; Fig. 8 shows a similar view Fig. 7, wherein a first straight line was adapted to the first track according to one embodiment; Fig. 9 shows a similar view Fig. 8, wherein the measuring tip has left a second track in a test area of ​​the sample and a second straight line has been adapted to the second track according to one embodiment; Fig. Figure 10 shows an approach curve, which represents a deflection of a free end of a boom of the device. Fig. 1 depending on the distance of a foot end of the boom according to one embodiment; Fig. Figure 11 shows a section of a sample with three test areas according to one embodiment; Fig. 12 shows a view similar to Fig. 10, wherein three approximation curves for the three test areas in Fig. 11 are shown according to one embodiment; Fig. Figure 13 illustrates automatic positioning of the measuring tip at a predetermined working distance to a sample according to one embodiment; Fig. Figure 14 illustrates a fully automatic iterative particle removal process according to one embodiment; Fig. Figure 15a shows various lateral distances used in the fully automated iterative particle removal process of Fig. 14 are applied according to one embodiment; Fig. Figure 15b shows various z-distances used in the fully automated iterative particle removal process of Fig. 14 are applied according to one embodiment; Fig. Figures 16a to 16c illustrate another fully automatic iterative particle removal process according to one embodiment; Fig. Figure 17 illustrates a first variant of a process in which it is checked whether a particle adheres to the measuring tip according to one embodiment; Fig. Figure 18 illustrates a second variant of a process in which it is checked whether a particle adheres to the measuring tip according to one embodiment; Fig. Figure 19 shows a change in brightness of a particle adhering to a measuring tip in the second variant of the process. Fig. 18 according to one embodiment; Fig. Figure 20 illustrates a third variant of a process in which it is checked whether a particle adheres to the measuring tip according to one embodiment; Fig. Figure 21 illustrates a fourth variant of a process in which it is checked whether a particle adheres to the measuring tip according to one embodiment; Fig. Figure 22 shows a flowchart of a computer-implemented procedure for processing a sample with the device from Fig. 1 according to one embodiment; Fig. Figure 23 shows a flowchart of a computer-implemented procedure for processing a sample with the device from Fig. 1 according to a further embodiment; Fig. Figure 24 shows a flowchart of a computer-implemented procedure for processing a sample with the device from Fig. 1 according to a further embodiment; Fig. Figure 25 shows a flowchart of a computer-implemented procedure for processing a sample with the device from Fig. 1 according to a further embodiment; Fig. Figure 26 illustrates a computer-implemented method for determining the actual apex of a measuring tip according to one embodiment, wherein in Fig. 26 a sample with a nanostructure for determining the actual apex of the measuring tip and the measuring tip are shown; Fig. Figure 27 shows a captured image in which the sample with the nanostructure and the measuring tip are made of Fig. 26 are covered, according to one embodiment; Fig. 28 illustrates a further embodiment of a nanostructure for determining the actual apex of the measuring tip; and Fig. Figure 29 shows a flowchart of a computer-implemented procedure for processing a sample with the device from Fig. 1 according to a further embodiment.

[0134] In the figures, identical or functionally equivalent elements have been labelled with the same reference symbols, unless otherwise indicated. Furthermore, it should be noted that the representations in the figures are not necessarily to scale.

[0135] Fig. Figure 1 schematically shows an embodiment of a device 100 for analyzing and / or processing a sample 102 using an atomic force microscope 104 as an example of a nanomanipulator. The atomic force microscope 104 has a measuring tip 106 for analyzing and / or processing the sample 102. The measuring tip 106 is arranged on a boom 108, which is movably attached to a positioning unit 110 (motion unit). In particular, the boom 108 has a first end 112 (base end 112) at which the boom 108 is movably attached to the positioning unit 110. Furthermore, the boom 108 has a second end 114 (free end 114) at which the measuring tip 106 is arranged. The positioning unit 110 allows the measuring tip 106 to be moved in three spatial directions x, y, z (translational movement in the x, y, and z directions). Movements in the x and / or y direction are referred to here as lateral movements.Movements in the z-direction are referred to here as approaching the measuring tip 106 to the sample 102 (negative z-direction) or as moving the measuring tip 106 away from the sample 102 (positive z-direction).

[0136] The device 100 comprises a housing 116 which, for example, is pressurized by means of a vacuum pump 118 to a residual gas pressure of 10 -5 - 10 -9 The atomic force microscope 104 is evacuatable in mbar. The atomic force microscope 104 is arranged in the housing 116. Furthermore, a sample stage 120 is provided for holding the sample 102. The sample stage 120 is preferably held by the housing 116 by means of a holder 122. The sample stage 120 can also have a further positioning unit 124 (not shown separately), by means of which the sample stage 120 can be moved relative to the holder 122, for example, in the three spatial directions x, y, and z, and, for example, about at least one axis (e.g., one parallel to the z-direction). Fig. 1 arranged axis) is rotatable. Reference numeral 126 designates a sample table assembly comprising the sample table 120, the holder 122 and the further positioning unit 124.

[0137] Furthermore, for example, a particle beam column (corpuscular beam column) 128 is arranged in the housing 116. The particle beam column 128 is configured to provide a particle beam 130. The particle beam column 128 can, in particular, be configured as a particle beam microscope and used to monitor the processing of the sample 102 with the measuring tip 106.

[0138] The particle beam column 128 is, for example, an electron column 128 configured to provide an electron beam 130. The electron column 128 can, in particular, be configured as an electron microscope. In the following, the particle beam column 128 is described as an electron column 128 by way of example.

[0139] In other examples, however, the particle beam column 128 can also be an ion column (not shown) which is set up to provide an ion beam.

[0140] In conjunction with a process gas supply unit 134, the electron column 128 can also be used to perform particle beam-induced processing on the sample 102. For this purpose, for example, a process gas 136 is supplied by means of the process gas supply unit 134, which is then irradiated with the particle beam 130.

[0141] The measuring tip 106 can measure a sample surface 138 ( Fig. 2) particle 132 adhering to sample 102 ( Fig. 3) are recorded. For this purpose, the measuring tip 106 is moved accordingly, for example, by means of the positioning unit 110. The sample stage 120 can also be moved by means of its additional positioning unit 124 to assist in this process. The recording of the particle 132 by the measuring tip 106 is monitored live, in particular with the electron microscope 128.

[0142] The measuring tip 106 is then moved by means of the positioning unit 110 to a storage unit (not shown), where the particle 132 is transferred from the measuring tip 106 to the storage unit.

[0143] In Fig. Figure 1 also shows a control device 140 for controlling the atomic force microscope 104 (e.g., the positioning unit 110), the sample stage 120 or the further positioning unit 124, the electron microscope 128, and / or the process gas supply unit 134. A human-machine interface 142 can be provided as part of the control device 140 or connected to the control device 140 for data transfer, either wired or wirelessly. The human-machine interface 142 includes, for example, a display device 144, a loudspeaker (not shown), a keyboard 146, a mouse pointer 148, a joystick, a game controller (not shown), or the like.

[0144] As in Fig. As shown in Figure 2, the atomic force microscope 104 can, for example, have a deflection detection device 150 (e.g., a light pointer device 150) for detecting the extent of the deflection D of the free end 114 of the boom 108 in the z-direction. The z-direction is, in particular, perpendicular to the sample 102 or to a principal extension plane E (xy-plane in Figure 2). Fig. 3) the sample 102 and / or the sample table (120). The deflection D of the free end 114 of the arm 108 in the z-direction is caused by forces acting between the measuring tip 106 and the sample 102 and is proportional to a spring constant of the arm 108. Thus, by measuring the deflection D, a force acting on the arm 108 in the z-direction can be determined.

[0145] The light pointer device 150 can also be used to detect the extent of a rotation R of the free end 114 of the boom 108 about the x-direction. A rotation R (twisting R, see Fig. 2) The movement of the free end 114 of the boom 108 around the x-direction can be caused by lateral forces acting between the measuring tip 106 and the sample 102.

[0146] The light pointer device 150 comprises, for example, a laser source 152 and a position-sensitive photodetector 154. A laser beam 156 emitted by the laser source 152 is directed towards the free end 114 of the cantilever 108 and reflected from there onto the photodetector 154. The photodetector 154 has, for example, four photosensitive areas ul, ur, bl, and br. In an undisplaced position of the cantilever 108, the laser beam 156, 158 is reflected into the center of the photodetector 154, as shown in Fig. Figure 2 shows that if the cantilever 108 is deflected in the positive or negative z-direction (deflection D), the reflected laser beam 158 travels like a light pointer on the photodetector 154. By measuring the received intensities in the four regions ul, ur, bl, and br of the photodetector 154, vertical and horizontal deflection signals (bending signals) of the cantilever 108 can be determined. The deflection signals are proportional to forces acting on the cantilever 108 in the z-direction (normal force) and also to lateral forces acting in the x-direction or y-direction.

[0147] The process can also, for example, involve a bending B ( Fig. 2) the measuring tip 106 relative to the arm 108. In particular, the interaction of the measuring tip 106 with the sample 102 can lead to a bending B (i.e., an elastic deformation) of the measuring tip 106 relative to the arm 108. For example, the measuring tip 106 can bend due to a lateral movement of the measuring tip 106 (in the x and / or y direction in Fig. 2) The measuring tip 106 bends when simultaneously in contact with the sample 102. The extent of this bending B of the measuring tip 106 can be determined by means of image processing in recorded images 160 of the measuring tip 106.

[0148] The illustrated device 100 ( Fig. 1, Fig. 2) comprises a number of optional elements that are not mandatory. These are, in particular, the housing 116, the vacuum pump 118, the sample stage device 126, the electron column 128 (or an ion column), the process gas supply unit 134, the human-machine interface 142, and the displacement detection device 150.

[0149] In Fig. Figure 3 shows an image 160 (e.g. a scanning electron microscope image 160, abbreviated: SEM image 160) of a section of an exemplary sample 102. Fig. 4 shows the one in Fig. 3. Section of sample 102 shown as Figure 160 in a cross-sectional view along line IV-IV in Fig. 3. Sample 102, for example, has structures 162 (e.g., absorber structures 152) with intervening trenches 164. H denotes a height of the structures 162. Furthermore, sample 102 shows an exemplary particle 132, which lies in one of the trenches 164 at the edge of one of the absorber structures 162 and must be removed. The reference numeral 166 in Fig. 3 and Fig. 4 denotes a substrate of sample 102.

[0150] Removing particles 132 using the atomic force microscope 104 requires manipulating the measuring tip 106 with an accuracy on the order of nanometers. It may be necessary to approach a particle 132 many times with the user-controlled measuring tip 106 and monitor the process in SEM images 160 until the particle 132 adheres to the measuring tip 106 and can be removed from the sample 102.

[0151] Furthermore, processing of sample 102, in particular the removal of particles 132 from sample 102, is made more difficult by the fact that the exact position of an apex 168 ( Fig. 2) of the measuring tip 106 is generally not known. The apex 168 of the measuring tip 106 is, in particular, the point and / or area of ​​the measuring tip 106 that first comes into contact with the sample 102 and / or with a particle 132 on the sample 102 when the measuring tip 106 approaches the sample 102 and / or a particle 132 on the sample 102. Due to the geometry of the measuring tip 106, the actual apex 168 of the measuring tip 106 may not be visible in SEM images 160, so the exact x and y position x1, y1 ( Fig. 5) the actual apex 168 cannot be determined from a REM image 160 alone.

[0152] In Fig. Figure 5 illustrates a measuring tip 106 with a geometry in which the apex 168 is arranged such that the apex 168 is obscured with respect to a line of sight S of the scanning electron microscope 128. Consequently, the actual apex 168 is not visible in an SEM image 260 ( Fig. 6) will not be visible. Rather, a spot 170 ( Fig. 5) the measuring tip 106 appears as apparent apex 170 in the SEM image 260. In the example of Fig. In example 6, the actual apex 168 is located at a lateral position x1, y1 and the apparent apex 170 at a lateral position x2, y2. Fig. 6. The y-position y1 of the actual apex coincides with the y-position y2 of the apparent apex 170. However, the x-position x1 of the actual apex 168 is shifted by a distance Δx from the x-position x2 of the apparent apex 170.

[0153] The following refers to the Fig. 1, Fig. 2, Fig. 3, Fig. 4, Fig. 5, Fig. 6, Fig. 7, Fig. 8, Fig. 9, Fig. 10, Fig. 11, Fig. 12, Fig. 13, Fig. 14, Fig. 15, Fig. 16, Fig. 17, Fig. 18, Fig. 19, Fig. 20, Fig. 21, Fig. 22, Fig. 23, Fig. 24 to Fig. 25 a computer-implemented method for processing a sample 102 with an atomic force microscope 104 is described.

[0154] In a first step S1 of the procedure, the positioning unit 110 is controlled to move the measuring tip 106 in the y-direction, so that the apex 168 of the measuring tip 106 is in contact with a surface 172 of the sample stage 120 or a surface 174 of the sample 102 in a test area 176 of the sample stage 120 or the sample 102, and the measuring tip 106 leaves a first trace 178 (e.g., a first scratch mark 178) on the surface 172, 174. The first trace 178 is, in particular, arranged parallel to the y-direction. For example, in Fig. 6 shows a test area 176 of sample 102. In other examples, however, the procedure can also be applied to a test area (not shown) of the sample stage 120. As in Fig. As illustrated in Figure 7, the apex 168 of the measuring tip 106 is thus scratched along the surface 172, 174 of the test area 176 in step S1 in the y-direction.

[0155] In a second step S2 of the procedure, the image acquisition device 128 is used to take at least one image 260' of the test area 176 in which the first track 178 is at least partially captured ( Fig. 7), targeted.

[0156] In a third step S3 of the procedure, an x-position x1 of the apex 168 of the measuring tip 106 is determined with respect to the x-direction based on the first track 178 captured in image 260'. For example, as in Fig. Figure 8 shows a straight line 180 adapted ("fitted") to the first track 178. Then, the x-position x1 of the actual apex 168 of the measuring tip 106 is defined as the x-position x G the line 180 is determined. For example, the x-position x1 of the actual apex 168 is determined relative to the x-position x2 of the apparent apex 170 of the measuring tip 106, e.g. as an x-offset Δx.

[0157] In a fourth step S4 of the procedure, the positioning unit 110 is controlled to move the measuring tip 106 in the x-direction, so that the apex 168 of the measuring tip 106 is in contact with the surface 174 of the sample 102 (or in other examples with the surface 172 of the sample stage 120) in the test area 176 and the measuring tip 106 leaves a second track 182 (e.g., a second scratch mark 182) on the surface 174. The second track 182 is specifically arranged parallel to the x-direction. As in Fig. As illustrated in Figure 9, the apex 168 of the measuring tip 106 is scratched along the surface 174 of the test area 176 in step S4 in the x-direction.

[0158] In a fifth step S5 of the procedure, the image acquisition device 128 is used to take at least one further image 260" of the test area 176, in which the second track 182 is at least partially captured ( Fig. 9), targeted.

[0159] In a sixth step S6 of the procedure, a y-position y1' of the apex 168 of the measuring tip 106 is determined with respect to the y-direction based on the second track 182 captured in the image 260" ( Fig. 9). For example, as in Fig. As shown in Figure 9, a straight line 184 is adapted to the second track 182. Then, the y-position y1' of the actual apex 168 of the measuring tip 106 is defined as the y-position y G the line 184 is determined. For example, the y-position y1' of the actual apex 168 relative to the y-position y2' of the apparent apex 170 of the measuring tip 106 is determined, e.g., as a y-offset Δy. In the example shown in the Fig. 6, Fig. 7, Fig. 8 to Fig. 9 the y-position y1, y1' of the actual apex 168 matches the y-position y2, y2' of the apparent apex 170 of the measuring tip 106, so that the y-offset Δy is zero.

[0160] With steps S1 to S6, the exact x and y position x1, y1 (x1', y1') of the actual apex 168 of the measuring tip 106 (e.g. relative to the apparent apex 170) can be determined, although only the apparent apex 170 of the measuring tip can be seen in the REM images 260, 260', 260".

[0161] Optionally, the proposed method can also include an approximation curve 186 ( Fig. 10) with respect to a deflection D ( Fig. 2) of the boom 108 as the measuring tip 106 approaches the specimen 102 parallel to the z-direction. In particular, attractive and / or repulsive forces act on the free end 114 of the boom 108 depending on the z-position Pz of the foot end 112 of the boom 108, which attract the free end 114 of the boom 108 to the specimen 102 or repel it from it. For the approach curve 186 ( Fig. 10) With regard to the deflection D of the free end 114 of the boom 108, a distance range is considered here with respect to the z-direction in which only repulsive forces act on the free end 114 of the boom 108 and / or in which a repulsive force is greater than an attractive force.

[0162] Using the approach curve 186, a safe deflection D can be determined. S ( Fig. 10) of the free end 114 of the boom 108 in the z-direction, whereby the sample 102 is not damaged by the measuring tip 106. The safe deflection D S The free end 114 of the boom 108 corresponds in particular to a safe minimum z-distance A S of the foot end 112 of the boom 108 from the sample 102 (i.e., in the z-direction). Determining the approach curve 186 is advantageous because the exact z-position z1 of the apex 168 ( Fig. 5) the position of the measuring tip 106 is generally unknown. In particular, the z-position Pz of the foot end 112 of the boom 108 is set and provided by the positioning unit 110. However, the exact z-position z1 of the apex 168 of the measuring tip 106 is generally unknown due to the changing deflection D of the free end 114 of the boom 108 and due to a possible bending B of the measuring tip 106 relative to the boom 108.

[0163] In a first step S1' of the procedure, the positioning unit 110 is controlled to move the foot end 112 of the boom 108 in the negative z-direction. This results in a z-distance A ( Fig. 5) between the foot end 112 of the boom 108 and the sample 102 is reduced and the measuring tip 106 is in a test area 188 ( Fig. 11) of sample 302 approached sample 302. The test area 188 is in particular arranged outside and / or spaced apart from structures 362, 364 (e.g. absorber structures) of sample 302.

[0164] In a second step S2' of the procedure, the deflection detection device 150 (e.g. the light pointer device 150, Fig. 2) repeatedly provides information about an extent D1, D2, D3 ( Fig. 10) the z-deflection D of the free end 114 of the boom 108 as a function of a set z-position Pz of the foot end 112 of the boom 108 (i.e. as a function of the z-distance A, A1, A2, A3 of the foot end 112 of the boom 108 from the specimen 302, see Fig. 5 and Fig. 10) received. Step S2' is performed in particular simultaneously with step S1'. In other words, the displacement detection device 150 measures the z-displacement D of the free end 114 of the boom 108 simultaneously or repeatedly during the movement of the measuring tip 106 in the negative z-direction (i.e., during the approach of the measuring tip 106 to the sample 302). In the example of Fig. 10 The foot end 112 of the boom 108 is brought close to the specimen 102 to a distance A3 at which a force acts on the free end 114 of the boom, causing a deflection D3. In particular, the distance A in Fig. 10 from left to right, so that A3 is smaller than A2 and A2 is smaller than A1.

[0165] In a third step S3' of the procedure, an approximation curve 186 ( Fig. 10). The approximation curve 186 indicates the extent D1, D2, D3 of the deflection D of the free end 114 of the boom 108 as a function of the distance A, A1, A2, A3 of the z-position Pz of the foot end 112 of the boom 108 from the sample 302. As in Fig. As shown in Figure 10, the deflection D of the boom 108 becomes smaller the closer the foot end 112 of the boom 108 – and thus also the measuring tip 106 – is brought to the sample 102, 302. In other words, the repulsive force acting on the measuring tip 106 becomes smaller the closer the measuring tip 106 is brought to the sample 102. One could also say that the atomic force microscope 104 is used here as a force sensor and force-distance spectroscopy is performed.

[0166] In a fourth step S4' of the procedure, at least one image 360 ​​of the sample 302 is received in which the test area 188 is at least partially captured ( Fig. 11).

[0167] In a fifth step S5' of the procedure, it is determined, based on the at least one received image 360, whether the sample 302 in the test area 188 is damaged. For example, the test area 188 (i.e., a material 190 of the test area 188) was in Fig. 11 not damaged by measuring tip 106.

[0168] In a sixth step S6' of the procedure, a minimum z-deflection D3 and / or a minimum z-distance A3 of the approximation curve 186 determined in step S3' is considered a safe z-deflection D3, D S of the free end 114 of the boom 108 or as a safe z-distance A3, A S of the foot end 112 of the boom 108 of the sample 102 is determined if in step S5' it is determined that the sample 302 is not damaged in the test area 188.

[0169] Optionally, the procedure uses several approximation curves 186, 186', 186" ( Fig. 12) based on different test areas 188, 188', 188" ( Fig. 11) determined. The test areas 188, 188', 188" differ from each other, in particular, by the type of material 190, 190', 190" of the respective test area 188, 188', 188". Then, at least one image 360 ​​is recorded with an image acquisition device 128 in which the test areas 188, 188', 188" are at least partially captured. It is also possible to record at least one image 360 ​​for each test area 188, 188', 188". Next, for each determined approximation curve 186, 186', 186" based on the at least one received image 360, it is determined whether the sample 302 is damaged in the respective test area 188, 188', 188". In the example of Fig. 11. The respective material 190, 190' of test areas 188, 188' was not damaged by the measuring tip 106. For test area 188" only, an indentation 200 left by the measuring tip 106 is illustrated as an example of damage to the material 190" of test area 188". Consequently, no damage to sample 302 is determined for test areas 188, 188'. Furthermore, damage to sample 302 is determined for test area 188" as an example. Next, a safe deflection D is determined. S , D S ' ( Fig. 12) the respective approximation curve 186, 186' depending on the corresponding material 190, 190' of the respective test area 188, 188' is stored if it is determined that the sample 320 is not damaged in the respective test area 188, 188'.

[0170] Optionally, in the proposed method, the measuring tip 106 can also be automatically positioned at a suitable predetermined working distance Δz2 to the sample 402, as shown in Fig. Figure 13 illustrates this. In particular, it may be provided that the positioning unit 110 is initially controlled to move the measuring tip 106 in the negative z-direction, so that the measuring tip 106 is brought into contact with the sample 102 (left figure in Figure 13). Fig. 13). Here, the distance Δz1 between measuring tip 106 and sample 402 is zero (Δz1=0). Next, it can be provided to set a predetermined working distance Δz2 between the measuring tip 106 and the sample 402, starting from the point of contact between the measuring tip 106 and the sample 402. For this purpose, either the positioning unit 110 can be used to move the measuring tip 106 towards the sample 402 and / or the further positioning unit 124 ( Fig. 1) to move the sample 402, which is arranged on the sample table 120, in the direction of the measuring tip 106. In particular, the positioning unit 110 and / or the further positioning unit 124 is controlled such that the measuring tip 106 and the sample 402 are moved to the predetermined distance Δz2 from each other (right figure in Fig. 13).

[0171] By setting the predetermined working distance Δz2, images can be taken (e.g. with the scanning electron microscope 128, Fig. 1) The samples 402, in which the measuring tip 106 is at least partially captured, can be compared more effectively. This allows for better monitoring of image-monitored processing processes, such as manipulation processes using the measuring tip 106 (e.g., displacement and / or removal of particles 132 from samples 102, 402).

[0172] Optionally, the proposed method can also include a fully automated iterative process for removing particles 532, as described in Fig. Figure 14 illustrates this. This significantly simplifies the removal of particles 532.

[0173] In a first step S1" of the iterative particle removal process, a removal trajectory T (e.g., a linear removal trajectory T) is provided for removing a particle 532 arranged on the sample 502. The removal trajectory T lies, in particular, in an xy-plane E spanned by the x and y directions ( Fig. 3) and intersects an xy position (x P , y P Fig. 3) of particle 132, 532. For illustrative purposes, particle 532 is shown in Fig. 14 is drawn as excessively large relative to the measuring tip 106. In reality, the particle 532 can be in Fig. 14 (and in other figures) however, are much smaller relative to the measuring tip 106.

[0174] In a second step S2" of the iterative particle removal process, the positioning unit 110 is controlled fully automatically to position the measuring tip 106 with respect to the z-direction at a first predetermined z-distance Δz3 (e.g. Δz3=50nm) from the sample 502.

[0175] In a third step S3" of the iterative particle removal process, the positioning unit 110 is automatically controlled to move 204 laterally (i.e., in the x and / or y direction) the measuring tip 106 along the determined removal trajectory T. Specifically, the measuring tip 106 is held at the first predetermined z-distance Δz3 to the sample 502, as set in step S2". In the example of Fig. In step S3, the movement of the measuring tip 103 occurs exclusively in the x-direction. In other examples, however, the movement of the measuring tip 103 in step S3 can also occur in the x- and y-directions or only in the y-direction.

[0176] Optionally, in process step S3," the measuring tip 106 is moved stepwise in individual steps 208 of a predetermined lateral distance Δl1 (e.g., Δl1 = 20 nm). Process step S3 can also be performed multiple times for different lateral distances Δl1, Δl2, as shown in Fig. Figure 15a illustrates this. The lateral distances Δl1, Δl2 increase with an increasing number of repetitions (e.g., Δl1 = 20 nm and Δl2 = 50 nm).

[0177] In a fourth step S4" of the iterative particle removal process, the positioning unit 110 is controlled fully automatically to move 206 ( Fig. 14) the measuring tip 106 in the positive z-direction away from the sample 502.

[0178] In a fifth step S5" of the iterative particle removal process, it is determined fully automatically whether the particle 532 is adhering to the measuring tip 106.

[0179] In a sixth step S6" of the iterative particle removal process, steps S2" to S5" are repeated fully automatically for one or more further predetermined z-distances Δz4, Δz5, Δz6, Δz7, as shown in Fig. Figure 15b illustrates this. The subsequent predetermined z-distances Δz4, Δz5, Δz6, Δz7 are, in particular, increasingly smaller than the first predetermined z-distance Δz3 (e.g., Δz4 = 40 nm, Δz5 = 30 nm, Δz6 = 20 nm, Δz7 = 10 nm). Steps S2" to S5" are repeated fully automatically for increasingly smaller z-distances Δz4, Δz5, Δz6, Δz7 until it is determined that the particle 532 adheres to the measuring tip 106.

[0180] Optionally, the proposed method can also include a further fully automated iterative process for removing particles 532, as described in Fig. Illustrated in sections 16a to 16c.

[0181] In a first step of the procedure, the positioning unit 110 is controlled to position the measuring tip 106 on a surface 538 of the sample 502 and adjacent to a particle 532 on the surface 538 of the sample 502. A foot point 112 of the boom 108 is located at a first predetermined z-distance z8 from the sample 502 with respect to the z-direction.

[0182] In a second step of the procedure, the positioning unit 110 is controlled to move the measuring tip 106 laterally (i.e. in the x and / or y direction) to detach the particle 532 from the surface 538.

[0183] In a third step of the procedure, it is determined whether the particle 532 is moving and / or has moved on the surface 538 (i.e., whether its position on the surface 538 has changed from an initial position in the first step).

[0184] The third step is carried out, for example, with the aid of an image acquisition device 128 ( Fig. 1) is carried out. For example, in both the first and third steps, at least one image in which particle 532 is detected is taken with the image acquisition device 128.

[0185] In a fourth step of the procedure, the first three steps are repeated for one or more further predetermined z-distances z9, z 10 ( Fig. 16b, Fig. 16c) between the base 112 of the boom 108 and the probe 502 is repeated. The further predetermined z-distances z9, z 10 are, in particular, increasingly smaller than the first predetermined z-distance z8. This results in a progressively increasing force being exerted on the measuring tip 106 and thus on the particle 532. As in Fig. 16b and Fig. As can be seen in 16c, the boom 108 bends increasingly. The first to third steps are performed for one or more further predetermined z-distances z9, z 10between the base point 112 of the boom 108 and the sample 502 is repeated until it is determined that the particle 532 has moved on the surface 538.

[0186] The first four steps are performed fully automatically.

[0187] By repeating the steps of the procedure for increasingly smaller z-distances z8, z9, z 10 Between the base 112 of the boom 108 and the sample 502, only as much force can be applied to the measuring tip 106 as is necessary to detach the particle 532 from the surface 538 without causing damage to the measuring tip 106 and / or the sample 538.

[0188] Optionally, the proposed method can also include a fully automatic move and lift movement of the measuring tip 106, as shown in Fig. Figure 17 illustrates this. For this purpose, the positioning unit 110 is first moved laterally 210 ( Fig. 17) the measuring tip 106 is moved towards a particle 632 located on the sample 602. Next, it is determined whether the particle 632 adheres to the measuring tip. The adhesion of the particle 632 to the measuring tip 106 can be verified based on various methods described below. If it is determined that the particle 632 adheres to the measuring tip 106, then the positioning unit 110 is moved to perform a lifting movement 212, 214 of the measuring tip 106. As shown in the middle of Fig. As shown in Figure 17, the lifting movement 212, 214 can, in a first variant, be a movement 212 of the measuring tip 106 exclusively in the positive z-direction. Furthermore, in a second variant, the lifting movement 212, 214 can be a movement 214 of the measuring tip 106 along a curved trajectory 215, which, in the region of the particle 632, bends from an initial lateral movement into a movement in the positive z-direction. Thus, a displacement and lifting movement 210, 212, 214 of the measuring tip 106, as may be required for picking up a particle 632 from the sample surface, including a check to see if the particle 632 adheres to the measuring tip 106, can be performed fully automatically.

[0189] Optionally, the proposed procedure can also include a (e.g., fully automated) check to determine whether a particle 632 ( Fig. 17) adheres to the measuring tip 106. For this purpose, the positioning unit 110 (e.g. as in Fig. 14 and / or Fig. (17 shown) to move the measuring tip 106 laterally and / or in the positive z-direction to pick up a particle 632 arranged on the sample 602 with the measuring tip 106. Then, according to one or more of the following four variants, it is determined whether the particle 632 adheres to the measuring tip 106.

[0190] In the first variant, based on a deflection detection device 150 ( Fig. 2) By detecting the extent of a lateral deflection of the boom 108 (i.e. in the x and / or y direction), it is determined whether the particle 632 is adhering to the measuring tip 106.

[0191] The lateral deflection of the boom 108 can be determined, for example, using the light pointer device 150. In particular, lateral forces acting between the measuring tip 106 and the sample 102 can cause a rotation R of the free end 114 of the boom 108 about the x-direction. Thus, the lateral deflection of the boom 108 can be determined, for example, by measuring the extent of the rotation R of the free end 114 of the boom 108 about the x-direction using the light pointer device 150.

[0192] In the second variant, based on a change in brightness ΔB and / or a change in contrast of particle 732 in images 760, 760' of particle 732, 732' (e.g. in electron microscope images and / or ion microscope images), it is determined whether the particle 732, 732' adheres to the measuring tip 106, as shown in Fig. 18 and Fig. Figure 19 illustrates this. In the several received images 760, 760' of sample 702, in addition to particle 732, 732', at least part of the measuring tip 106 is also captured. In image 760 ( Fig. 18) Particle 732 is not yet attached to the measuring tip 106. In contrast, in the further image 760' ( Fig. 19) The brightness B2 of particle 732' is significantly increased compared to the brightness B1 of particle 732 in image 760 (i.e., particle 732' in image 760' is brighter than particle 732 in image 760). The change in brightness ΔB results in particular from the difference between brightnesses B1 and B2. In other words, there is a contrast between particle 732' and the measuring tip 106 in Fig. 19 greater than a contrast between particle 732 and measuring tip 106 in Fig. 18. This is an indication of an electrical charge of particle 732' in Fig. 19 due to the adhesion and thus to the fact that particle 732' in Fig. 19 is attached to the measuring tip 106.

[0193] In the third variant, based on the migration of particle 832, 832' from a fixed focus of the image acquisition device 128, it is determined that the particle 832' adheres to the measuring tip 106, as in Fig. Figure 20 illustrates this. This indicates that particle 832' is lifted together with the measuring tip 106. In particular, it is determined from Figures 860 and 860' that particle 832 initially (Figure 860, left in Fig. 20) is located in a focus of the image acquisition device 128, and the particle 832' is visible in later images 860' (right in Fig. 20) is no longer in focus of the image acquisition device 128.

[0194] In the fourth variant, the images 160 ( Fig. 3) of particle 132 is recorded with the image acquisition device 128 using an autofocus setting focused on particle 132. Furthermore, based on an automatic adjustment ΔF ( Fig. 21) The deviation of the autofocus focused on particle 132 by more than the predetermined threshold ΔFs indicates that the z-position Pz of particle 132 has changed significantly, which suggests that particle 132 was lifted together with the measuring tip 106 (in the positive z-direction). Fig. Figure 21 illustrates a change ΔF of the autofocus. An automatic adjustment ΔF1 that is greater than the threshold value ΔFs can, for example, be interpreted as an indication of movement of the particle 132 corresponding to adhesion to the measuring tip 106.

[0195] Optionally, the proposed method can also include fully automatic centering of the measuring tip 106 and the sample stage 120. In particular, the atomic force microscope 104 comprises the sample stage assembly 126 with the mount 122, the sample stage 120 laterally movable on the mount 122, and the additional positioning unit 124 for laterally moving the sample stage 120 relative to the mount 120 in the x and y directions. The sample stage 120 can, for example, also be rotatably mounted on the mount 122 so that it can be rotated about the x, y, and / or z directions using the additional positioning unit 124.

[0196] In a first step S1''' of the procedure, the positioning unit 110 is controlled to automatically position the measuring tip 106 in a preset initial position Px0, Py0 (e.g. at x=0 and y=0) with respect to the x and y directions.

[0197] In a second step S2''' of the procedure, at least one image 160 of the sample 102, in which a particle 132 arranged on the sample 102 is recorded, is taken.

[0198] In a third step S3''' of the procedure, a lateral position x is determined. P , y P ( Fig. 3) of the particle 132 captured in at least one image 160 by means of image processing.

[0199] In a fourth step S4''' of the procedure, the further positioning unit 124 is controlled to move the sample table 120 laterally relative to the holder 122, so that the lateral position x P , y P of particle 132 with the initial position Px0, Py0 of the measuring tip 106 in relation to the x and y directions.

[0200] The described methods allow for a more precise determination of the x, y, and / or z position of the apex 168 of the measuring tip 106, enabling more precise processing of the sample 102 with the measuring tip 106. Furthermore, the necessary manipulations with the measuring tip 106 on nanometer scales can be simplified and / or automated in a variety of ways.

[0201] In the Fig. 26, Fig. 27 to Fig. 28 is another computer-implemented method for processing a sample 102 with a nanomanipulator 104 ( Fig. 1) Illustrated. The nanomanipulator 104 has a measuring tip 106 for processing the sample 102 and a positioning unit 124 for moving the measuring tip 106. In Fig. Figure 26 shows only the measuring tip 106 of the nanomanipulator 104; other components of the nanomanipulator 104, such as the positioning unit 124, a sample stage 120 on which the sample 102 is arranged, and an image acquisition unit 128, are shown in Figure 26. Fig. Reference is made to Figure 1 and its description. An x-direction and a y-direction of the nanomanipulator 104 are each arranged parallel to a principal extension plane E of the sample 102 and / or the sample stage 120 and perpendicular to each other. The sample 120 has a nanostructure 900 on its surface 902 for determining an actual apex 904 of the measuring tip 106.

[0202] In a first step S1'''' of the procedure, the positioning unit 124 is used to move the measuring tip 106 laterally (in the x and / or y direction) from lateral initial coordinates x A to lateral end coordinates x E The nanostructure 900 is scanned. Raster data 906 is generated in the process.

[0203] In Fig. 26 is an example and, for illustrative purposes, is used as the initial lateral coordinate x. A and as the lateral end coordinate x E Each x-coordinate is specified. However, the lateral start and end coordinates can each include an x- and / or y-coordinate as a position specification.

[0204] In a second step S2'''' of the procedure, nanostructure coordinates x N a highest point 908, 910 of the nanostructure 900 in the raster data 906 determined.

[0205] In Fig. 26 is also known as the nanostructure coordinate x N An x-coordinate is given. The nanostructure coordinate x N However, it can also have an x ​​and / or y coordinate as a position specification.

[0206] In a third step S3'''' of the procedure, a first lateral distance C1 between the nanostructure coordinates x is determined. Nand the lateral end coordinates x E determined.

[0207] In a fourth step S4'''' of the procedure, at least one image 912 ( Fig. 27) of sample 102, in which the measuring tip 106 and the nanostructure 900 are at least partially captured. The actual apex 904 of the measuring tip 106 (not visible in image 912) is located at the lateral end coordinates x. E In Fig. 27 is also shown as an apparent apex 914 of the measuring tip 106, visible in image 912.

[0208] In a fifth step S5"" of the procedure, a second distance C2 is determined between the apparent apex 914 of the measuring tip 106 and the nanostructure 900 (e.g., the nanostructure coordinate x). N ) determined in image 912 (e.g. by image analysis).

[0209] In a sixth step S6'''' of the procedure, a lateral position x is determined. E , x' EThe actual apex 904 of the measuring tip 106 is determined based on the difference between the first and second distances C1, C2. For example, a third distance C3 between the apparent apex 914 and the actual apex 904 of the measuring tip 106 is determined by subtracting the second distance C2 from the first distance C1.

[0210] In this way, a position x can be E , x' E of the actual apex 904 of the measuring tip 106, which is not visible in the image 912, can nevertheless be determined.

[0211] The nanostructure 900 for determining the actual apex 904 of the measuring tip 106, for example, has a lateral size G ( Fig. 26) of 30 nm or less, 20 nm or less, 10 nm or less and / or 5 nm or less.

[0212] In the example of Fig. 26, Fig. 27 The nanostructure 900 for determining the actual apex 904 of the measuring tip 106 has a spherical shape and / or a spherical surface.

[0213] As in Fig. As shown in Figure 28, a nanostructure 916 for determining the actual apex 904 of the measuring tip 106 can, for example, also have a tip 918 which tapers away from the sample surface 902 in one direction.

[0214] Although the present invention has been described using exemplary embodiments, it can be modified in many ways. REFERENCE MARK LIST 100 Device 102 Sample 104 Nanomanipulator (atomic force microscope) 106 Measuring tip 108 cantilevers 110 Positioning unit 112 End 114 End 116 cases 118 Pump 120 sample table 122 bracket 124 Positioning unit 126 Sample table setup 128 particle column 130 particle beam 132 Defect (particle) 134 Process gas supply unit 136 Process gas 138 surface 140 Control device 142 Human-Machine Interface 144 Display unit 146 keyboard 148 mouse pointers 150 deflection detection device 152 Laser source 154 Photodetector 156 Laser beam 158 Laser beam 160 images 162 Structure 164 Trench 166 substrate 168 actual apex 170 apparent apex 172 surface area 174 surface 176 area 178 track 180 Straight 182 track 184 Even 186, 186', 186" approach curve 188, 188', 188" area 190, 190', 190" Material 200 impressions 204 Movement 206 Movement 208, 208' step 210 Movement 212 Movement 214 Movement 215 Trajectory 260, 260', 260" image 302 Sample 360 image 362 structures 364 trenches 402 Sample 438 surface 502 Sample 532 particles 538 surface 602 Sample 632 particles 702 Sample 732, 732' particles 760, 760' image 802 particles 832, 832' particles 860, 860' image 900 Nanostructure 902 surface 904 actual apex 906 raster data 908 points 910 points 912 Image 914 apparent apex 916 Nanostructure 918 peak A, A1, A2, A3 Distance As, As' distance bl area br area B Bending B1, B2 Brightness C1, C2, C3 distance D deflection D1, D2, D3, D3" deflection Ds, Ds' deflection ΔB brightness difference ΔF, ΔF1 focus change ΔFs threshold Δl1, Δl2 distance Δx distance, offset Δy Offset Δz1 - Δz9 distance Level E Size G H height Px, Py, Pz Position Px0, Py0 Position R twist S line of sight S1-S6 process steps S1'-S6' Process steps S1''- S6" process steps S1'''-S4''' Process steps S1''''-S6'''' Process steps T long-distance trajectory ul area our area x, y, z direction x1, x2 position x1', x2' Position x A , x E , x' E Position x G Position x N Position x P Position y1, y2 Position y1', y2' Position yG Position y P Position

Claims

[1] Computer-implemented method for processing a sample (102) with a nanomanipulator (104) comprising a measuring tip (106) for processing the sample (102) and a positioning unit (110) for moving the measuring tip (106), wherein the sample (102) is arranged on a sample stage (120), and an x-direction (x) and a y-direction (y) of the nanomanipulator (104) are each arranged parallel to a principal extension plane (E) of the sample (102) and / or the sample stage (120) and perpendicular to each other, comprising the steps: 1a) Controlling (S1) the positioning unit (110) to move the measuring tip (106) in the y-direction (y) such that an apex (168) of the measuring tip (106) is in contact with a surface (138, 172) of a test area (176) of the sample stage (120) or the sample (102) and the measuring tip (106) leaves a first trace (178) on the surface (138, 172), 1b) Controlling (S4) the positioning unit (110) to move the measuring tip (106) in the x-direction (x) so that the apex (168) of the measuring tip (106) is in contact with the surface (138, 172) and the measuring tip (106) leaves a second track (182) on the surface (138, 172), 1c) Controlling (S2, S5) an image acquisition device (128) to capture at least one image (260, 260', 260") of the test area (176) in which the first and second tracks (178, 182) are at least partially captured, and 1d) Determining (S3, S6) an x-position (x1, x1') of the apex (168) of the measuring tip (106) with respect to the x-direction based on the first track (178) captured in the at least one image (260') and determining a y-position (y1, y1') of the apex (168) of the measuring tip (106) with respect to the y-direction based on the second track (182) captured in the at least one image (260"). [2] Method according to claim 1, wherein the nanomanipulator (104) has a boom (108) with a foot end (112) and a free end (114), the measuring tip (106) is arranged at the free end (114) of the boom (108), the boom (108) is movably attached to the positioning unit (110) at its foot end (112), and the positioning unit (110) is controlled to move the foot end (112) of the boom (108) so that the measuring tip (106) is moved. [3] Method according to claim 1 or 2, wherein the x-position (x1, x1') and the y-position (y1, y1') of the apex (168) of the measuring tip (106) are determined by adjusting a respective straight line (180, 184) accordingly to the first and second track (178, 182) captured in the image (260', 260"). [4] Method according to any one of claims 1 to 3, wherein the measuring tip (106) is at least partially captured in the at least one image (260, 260', 260"), a lateral position (x2, y2) of an apparent apex (170) of the measuring tip (106) in the at least one image (260, 260', 260") differs from a lateral position (x1, y1) of an actual apex (168) of the measuring tip (106) in the at least one image (260, 260', 260"), and the lateral position (x1, y1) of the actual apex (168) of the measuring tip (106) is determined relative to the lateral position (x2, y2) of the apparent apex (170) of the measuring tip (106) in the at least one image (260, 260', 260"). [5] Method according to any one of claims 2 to 4, wherein the lateral position (x1, y1) of the actual apex (168) of the measuring tip (106) is determined relative to a lateral position (x2, y2) of the foot end (112) of the boom (108). [6] Method according to any one of claims 2 to 5, wherein the nanomanipulator (104) has a deflection detection device (150) for detecting a deflection (D) of the free end (114) of the boom (108) in a z-direction (z) which is arranged perpendicular to the x- and y-directions (x, y) and points away from the sample (102, 302), and wherein the method comprises: 6a) Controlling (S1') the positioning unit (110) to move the foot end (112) of the boom (108) in a negative z-direction (z), so that the measuring tip (106) is brought close to the sample (302) in a test area (188) of the sample (302), 6b) repeated reception (S2') from the deflection detection device (150) of a magnitude (D1, D2, D max ) the deflection (D) of the free end (114) of the boom (108) in the z-direction (z) as a function of a z-position (Pz) of the foot end (112) of the boom (108), 6c) Determine (S3') an approximation curve (186) which determines the extent (D1, D2, D max ) the deflection (D) of the free end (114) of the boom (108) as a function of the z-position (Pz) of the foot end (112) of the boom (108), 6d) Receiving (S4') at least one image (360) of the sample (302) in which the test area (188) is at least partially captured, 6e) Determine (S5') based on the at least one received image (360) whether the sample (302) in the test area (188) is damaged, and 6f) Storing (S6') a maximum displacement (D max ) of the approach curve (186) as a safe maximum deflection (D S ) of the free end (114) of the boom (108) if it is determined that the sample (302) in the test area (188) is not damaged. [7] Method according to claim 6, wherein: Several approximation curves (186, 186', 186") are determined based on several different test areas (188, 188', 188"), which differ from each other by a type of material (190, 190', 190") of the respective test area (188, 188', 188"). at least one image (360) is received in which the several test areas (188, 188', 188") are at least partially captured, For each determined approximation curve (186, 186', 186") based on the at least one received image (360), it is determined whether the sample (302) is damaged in the respective test area (188, 188', 188"), and a maximum displacement (D max , D max ') of the respective approach curve (186, 186') as a safe maximum deflection (D S , D S') of the free end (114) of the boom (108) depending on the corresponding material (190, 190') of the respective test area (188, 188') is stored when it is determined that the sample (302) in the respective test area (186, 186') is not damaged. [8] Method according to any one of claims 1 to 7, wherein: the nanomanipulator (104) preferably comprises a sample stage device (126) with a holder (122), a sample stage (120) movably arranged on the holder (122) and a further positioning unit (124) for moving the sample stage (120) relative to the holder (122), and the procedure exhibits: 8a) Controlling the positioning unit (110) to move the measuring tip (106) in the negative z-direction (z) so that the measuring tip (106) is brought into contact with the sample (402), and 8b) Controlling the positioning unit (110) and / or the further positioning unit (124) to move the measuring tip (106) or the sample (402) arranged on the sample table (120), so that the measuring tip (106) and the sample (402) are brought to a predetermined distance (Δz2) from each other. [9] Method according to any one of claims 1 to 8, comprising: 9a) Providing (S1") a remote trajectory (T) for removing a particle (532) arranged on the sample (502), wherein the remote trajectory (T) lies in an xy-plane (E) spanned by the x and y directions (x, y) and an x ​​and y position (x P , y P ) of particle (532) cuts, 9b) Controlling (S2") the positioning unit (110) to position the measuring tip (106) with respect to the z-direction (z) at a first predetermined z-distance (Δz3) from the sample (502), 9c) Controlling (S3") the positioning unit (110) to laterally move the measuring tip (106) along the determined distance trajectory (T) and at the first predetermined z-distance (Δz3) to the sample (502), and 9d) Controlling (S4") the positioning unit (110) to move the measuring tip (106) in the positive z-direction (z) away from the sample (502), 9e) Determine (S5") whether the particle (532) adheres to the measuring tip (106), and 9f) Repeat (S6") steps 9b) to 9e) for one or more further predetermined z-distances (Δz4, Δz5, Δz6, Δz7), which are progressively smaller than the first predetermined z-distance (Δz3), until it is determined that the particle (532) adheres to the measuring tip (106), where steps 9b) to 9f) are executed fully automatically. [10] Method according to claim 9, wherein step 9c) comprises: Controlling the positioning unit (110) to laterally move the measuring tip (106) along the determined distance trajectory (T) in steps (208) of a first predetermined lateral distance (Δl1) and preferably in steps (208') of one or more further predetermined lateral distances (Δl2), which are increasingly larger than the first predetermined lateral distance (Δl1). [11] Method according to any one of claims 1 to 10, comprising: 12a) Controlling the positioning unit (110) to move (210) the measuring tip (106) laterally in the direction of a particle (632) arranged on the sample (602), 12b) Determine whether the particle (632) adheres to the measuring tip (106), 12c) Controlling the positioning unit (110) to move (212) the measuring tip (106) in a positive z-direction (z) away from the sample (602) and / or to move the measuring tip (106) along a curved trajectory (214) which, in the region of the particle (632), bends from an initial lateral movement into a movement in a positive z-direction (z) when it is determined that the particle (632) is adhering to the measuring tip (106), where steps 12a) to 12c) are carried out fully automatically. [12] Method according to any one of claims 2 to 11, comprising: Controlling the positioning unit (110) to move the measuring tip (106) in a lateral direction (x, y) and / or in a positive z-direction (z) to pick up a particle arranged on the sample (132) with the measuring tip (106), Determine whether the particle (132) adheres to the measuring tip (106) based on: a deflection of the boom (108) in a lateral direction (x, y) received by a deflection detection device (150), several received images (760, 760') of at least part of the sample (702) in which the particle (732, 732') is detected, and a brightness change (ΔB) of the particle (732, 732') and / or contrast change of the particle (732, 732') relative to the measuring tip (106) in the several images (760, 760') determined by means of image processing, several images (860, 860') received by an image acquisition device (128) of at least a part of the sample (802) in which the particle (832, 832') is detected, and a migration of the particle (832, 832') from a fixed focus of the image acquisition device (128) determined by image processing of the several images (860, 860'), and / or information received from an image acquisition device (128), which takes images (160) of at least part of the sample (102) in which the particle (132) is detected, with an autofocus setting focused on the particle (132), about the extent (ΔF1) of an automatic adjustment (ΔF) of the autofocus focused on the particle (132), which is greater than a predetermined threshold (ΔF) S ) is. [13] Method according to any one of claims 1 to 12, wherein: the nanomanipulator (104) has a sample stage device (126) with a holder (122), a sample stage (120) arranged laterally movable on the holder (122) and a further positioning unit (124) for laterally moving the sample stage (120) relative to the holder (122) in the x and y directions (x, y), the procedure exhibits: 14a) Controlling (S1''') the positioning unit (110) to position the measuring tip (106) in a lateral initial position (Px0, Py0) preset in the positioning unit (110) with respect to the x and y directions (x, y), 14b) Receiving (S2''') at least one image (160) of the sample (102) in which a particle (132) arranged on the sample (102) is detected, 14c) Determine (S3''), based on image processing, a lateral position (x P , y P ) of the particle (132) captured in the at least one image (160), and 14d) Controlling (S4''') the further positioning unit (124) to laterally move the sample table (120) with the sample (102) such that the lateral position (x P , y P ) of the particle (132) coincides with the lateral initial position (Px0, Py0) of the measuring tip (106) with respect to the x and y directions (x, y), and Steps 14a) to 14d) are executed fully automatically. [14] Device (100) for processing a sample (102), comprising: a nanomanipulator (104) with a measuring tip (106) for processing the sample (102) and a positioning unit (110) for moving the measuring tip (106), a sample stage (120) for arranging the sample (102), wherein an x-direction (x) and a y-direction (y) of the nanomanipulator (104) are each arranged parallel to a principal extension plane (E) of the sample (102) and / or the sample stage (120) and perpendicular to each other, and a control device (140) configured to perform the method according to any one of claims 1 to 13.

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