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), comprising the steps: a) Providing allowed value ranges for two or more parameters (A1, A2) of the nanomanipulator (104) and / or the sample (102), wherein the two or more parameters (A1, A2) span a multidimensional parameter space (164), b) Determining an allowed range (166) in the multidimensional parameter space (164) based on the provided allowed ranges of values ​​for the two or more parameters (A1, A2), c) Receiving current values ​​(Z1, Z2) and / or determining future values ​​(Z1', Z2') of the two or more parameters (A1, A2), d) Determine whether a state point (Z, Z') corresponding to the current and / or future values ​​(Z1, Z2, Z1', Z2') of the two or more parameters (A1, A2) lies outside the allowed range (166) in the multidimensional parameter space (164), and e) Controlling the positioning unit (110) to stop a movement of the measuring tip (106) and / or to retract the measuring tip (106) relative to the sample (102) when it is determined that the state point (Z, Z') is outside the allowed range (166).

Description

[0001] The present invention relates to a computer-implemented method and apparatus 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 equipped with an illumination system and a projection system. The image of a mask (reticle) illuminated by the illumination system is projected by the projection system onto a substrate coated with a light-sensitive layer (photoresist) and arranged in the image plane of the projection system, for example, a silicon wafer, in order to transfer the mask structure to the light-sensitive coating of the substrate.

[0003] The mask (i.e., lithography mask) is used for a multitude of exposures, so it is very important that the mask is free of defects and contaminants. Therefore, lithography masks are extensively examined for defects and contaminants. Attempts are then made to repair any detected defects or remove contaminants. The defects and contaminants can be extremely small, measuring in the range of a few nanometers. Therefore, devices with very high spatial resolution are required to remove them.

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

[0005] These can be metal particles, especially tin, but ceramic particles, polymer particles, and other carbon compounds can also be present. The particles are typically adsorbed on 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 (e.g., Coulomb forces and van der Waals forces) applied to remove the particle are greater than the attractive forces (e.g., Coulomb forces and van der Waals forces) exerted by the mask surface. Depending on the type of interaction between the particle and the mask surface, an activation energy may be required to break the existing bond to the mask surface.

[0007] Processing devices are known with which individual particles can be specifically removed from a surface (particle removal tool, PRT). Nanomanipulators, such as atomic force microscopes, are used for this purpose. A particle is picked up with a measuring tip (measuring and manipulating tip) of the nanomanipulator and removed from the mask surface while adhering to the measuring tip. Particle removal is usually supported by imaging techniques (e.g., capturing images using a scanning electron microscope and / or a scanning ion microscope) and requires user manipulation on the nanometer scale. Small errors by a user can easily lead to damage or destruction of the measuring tip of the nanomanipulator or the sample.In addition, processing requires a high level of attention from the user, which leads to fatigue and an increased risk of user errors.

[0008] Against this background, one object of the present invention is to improve the processing of a sample with a nanomanipulator.

[0009] Accordingly, a computer-implemented method for processing a sample using a nanomanipulator is proposed. The nanomanipulator has a measuring tip for processing the sample and a positioning unit for moving the measuring tip. The method comprises the following steps: a) Providing permissible value ranges for two or more parameters of the nanomanipulator and / or the sample, whereby the two or more parameters span a multidimensional parameter space, b) Determining a permissible range in the multidimensional parameter space based on the provided permissible value ranges for the two or more parameters, c) receiving current values ​​and / or determining future values ​​of the two or more parameters, d) Determine whether a state point in the multidimensional parameter space corresponding to the current and / or future values ​​of the two or more parameters lies outside the allowed range, and e) controlling the positioning unit to stop movement of the measuring tip and / or to retract the measuring tip with respect to the sample when it is determined that the state point is outside the permitted range.

[0010] The method allows multiple parameters of the nanomanipulator and / or the sample (e.g., process parameters of the nanomanipulator and / or sample properties) to be monitored automatically and simultaneously. In particular, the parameters are monitored fully automatically, i.e., without user intervention. For example, the parameters are monitored using a control device.

[0011] The method involves determining a permissible range in the multidimensional parameter space spanned by the plurality of monitored parameters. The permissible range is determined, for example, by the control device. The permissible range is defined in such a way that, for state points within the permissible range, damage to the sample and / or impairment of the function of the nanomanipulator and / or damage to the nanomanipulator (e.g., the measuring tip, the cantilever, or other components of the nanomanipulator) is prevented. The method is used, for example, by the control device to check whether a current and / or future state point assumed by the system comprising the nanomanipulator and sample is within or outside the permissible range with regard to the monitored parameters. If a current and / or future state point is outside the permissible range, the following actions are taken, for example:Safety measures to protect the sample and / or the nanomanipulator are automatically initiated by the control device. In particular, a movement of the measuring tip (e.g., a lateral movement and / or a movement in a plane parallel to a main extension plane of the sample and / or an approach movement of the measuring tip with respect to the sample) is stopped and / or the measuring tip is retracted with respect to the sample (e.g., removed from the sample).

[0012] By stopping a movement (e.g. lateral movement and / or approach movement towards the sample) of the measuring tip, penetration into a forbidden area in the multi-dimensional parameter space can be prevented. For example, the multi-dimensional parameter space can include a force on the measuring tip perpendicular to the sample surface and a force on the measuring tip parallel to the sample surface. Then, by stopping a movement of the measuring tip, penetration into a forbidden area in which an inadmissibly high force is applied to the measuring tip perpendicular to the sample surface and / or parallel to the sample surface can be prevented. For example, the multi-dimensional parameter space can also, in addition to or instead, include a position (e.g. lateral position and / or a distance from the sample) of the measuring tip relative to the sample. Then, by stopping a movement (e.g.lateral movement and / or approach movement to the sample) of the measuring tip, for example, can prevent harmful interaction (e.g. collision) with structures of the sample.

[0013] By retracting the measuring tip with respect to the sample, i.e. moving the measuring tip perpendicular to the sample and in a direction away from the sample, contact of the measuring tip with the sample can be terminated and / or a distance between the measuring tip and the sample can be increased.

[0014] The determined permissible range in the multidimensional parameter space is a range in which safe processing of the sample with the nanomanipulator and safe operation of the nanomanipulator is possible.

[0015] The sample is, for example, a lithography mask with structures (e.g., absorber structures). The structures have, for example, a structure size in the range of 10 nm - 10 µm. The structures are arranged, for example, in a structure pattern for producing a specific type of semiconductor chip. The sample can be, for example, a transmissive lithography mask for DUV lithography (DUV: "deep ultra violet," working light wavelengths in the range of 30 - 250 nm) or a reflective lithography mask for EUV lithography (EUV: "extreme ultra violet," working light wavelengths in the range of 1 - 30 nm, especially 13.5 nm).

[0016] The sample may 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.

[0017] The nanomanipulator, e.g. the atomic force microscope, and / or a higher-level device comprising the nanomanipulator, comprises, for example, a sample table device with a holder, a sample table movably arranged on the holder for arranging the sample, and a further positioning unit for moving the sample table relative to the holder. The sample table can, for example, be moved in the x- and y-direction (i.e., laterally) and / or in the z-direction (vertically) using the further positioning unit. The sample table can, for example, also be rotatably mounted on the holder so that it can be moved around the x-axis using the further positioning unit. - , y - and / or z-direction. The sample stage has, in particular, a surface for arranging the sample.

[0018] The nanomanipulator, e.g., the atomic force microscope, has, for example, 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 also referred to below as a "cantilever." The measuring tip has, for example, a length in the range of 0.5 µm - 1 mm and a diameter in the range of 20 nm - 1 µm. In particular, the measuring tip can taper towards its free end. The measuring tip comprises, for example, a material that includes carbon, silicon, one or more precious metals, tungsten, platinum, iridium, and / or a platinum-iridium alloy. With the measuring tip, it is possible to specifically move to individual positions on the sample surface, especially when the sample has structures with a high aspect ratio. The aspect ratio can be defined, for example, as the ratio of the width to the height of a structure.An example of a structure with a high aspect ratio of 1:10 is a narrow, deep trench that is, for example, 1 µm wide and 10 µm deep.

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

[0020] The nanomanipulator has a positioning unit to which the cantilever is movably mounted and with which the cantilever can be moved in three spatial directions relative to the positioning unit (translational movement in the three spatial directions). The three spatial directions, in particular, span a three-dimensional space. The positioning unit is attached, for example, to a housing of the nanomanipulator and / or a higher-level device that houses the nanomanipulator.

[0021] The cantilever, in particular, has an elongated shape with a longitudinal axis. Furthermore, the cantilever is attached to the positioning unit at a first end, movable relative to its longitudinal axis. With the help of the positioning unit, the position of the first end of the cantilever (also called the base point or base end of the cantilever) can be adjusted in the three spatial directions. Furthermore, the cantilever has the measuring tip at a second end relative to its longitudinal axis.

[0022] When the measuring tip approaches the sample surface, an interaction occurs between the measuring tip and the sample surface. The interaction can be based on direct contact, a van der Waals interaction, other physical interactions, or a mixture of these. By scanning the sample surface with the measuring tip, a three-dimensional image of the sample surface can be captured. For example, the distance between the measuring tip and the sample surface is kept constant for each scanning position using a closed control loop, and the position of a microactuator for adjusting the distance is recorded.

[0023] A particle is, in particular, a foreign body, such as dust or dirt, that has settled on the sample surface. The particle can also be said to be adsorbed onto the sample surface. Particles adsorbed onto the sample surface can have different properties and different shapes. For example, the particle size can range from 3 nm to 50 µm and / or 10 nm to 1 µm.

[0024] Such a particle can be located on the sample surface using optical analysis methods, for example, and targeted with the measuring tip. To pick up the particle with the measuring tip, the particle must be released from the sample surface. This means that the forces acting between the sample surface and the particle must be overcome. How strongly the particle is bound to the sample surface depends on both the shape and nature of the particle and the nature of the sample surface, particularly its surface energy. The higher the surface energy of the surface, the more strongly the particle is adsorbed.

[0025] To pick up a particle with the measuring tip, for example, 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.

[0026] It can be helpful to first move the particle with the measuring tip across the sample surface to break existing bonds between the particle and the sample surface. This can, for example, reduce the particle's binding energy with respect to its binding to the surface. Furthermore, it can, for example, increase the contact area between the measuring tip and the particle. As the contact area between the particle and the measuring tip increases, the probability that the particle will adhere to the measuring tip and detach from the sample surface increases.

[0027] After the particle has been picked up by the measuring tip, it must be removed from the measuring tip to continue using the measuring tip. The particle should be placed in a position on the sample surface where it will not cause interference, or on a separate storage unit.

[0028] The nanomanipulator can be part of a higher-level device for processing the sample, which includes the nanomanipulator. The higher-level device for processing the sample can, for example, also include a control device for carrying out the proposed method. Furthermore, the higher-level device for processing the sample can, for example, also include an image recording device for recording images of the sample, such as a scanning electron microscope and / or a scanning ion microscope.

[0029] To safely process the sample with the nanomanipulator, parameters of the nanomanipulator and / or the sample, such as process parameters of the nanomanipulator and sample properties, are monitored. For this purpose, a control device (e.g., of the nanomanipulator and / or the higher-level device) receives, for example, current values ​​of two or more of these parameters. The control device can also be configured, for example, to determine (i.e., predict) future values ​​of two or more of these parameters based on stored information and / or received information.

[0030] Receiving the current values ​​and / or determining the future values ​​of the two or more parameters occurs in particular while the sample is being processed with the measuring tip.

[0031] Furthermore, the method provides permissible value ranges for the two or more parameters. These permissible value ranges are, for example, predetermined permissible value ranges that are stored in a memory device of the control device and / or received by the control device. The permissible value ranges for the two or more parameters are, in particular, each one-dimensional value range. If, for example, one of the monitored parameters is a force on the measuring tip perpendicular to the sample surface, then a permissible value range is, for example, the range from zero force to a maximum permissible value of the force F max perpendicular to the sample surface and / or up to a maximum permissible positive or negative force perpendicular to the sample surface.

[0032] For example, the permissible range can also be calculated based on the permissible value ranges for the two or more parameters and on a calculation of the probability of damage to the sample (damage probability). This damage probability depends strongly nonlinearly on the parameters.

[0033] The two or more monitored parameters span a multidimensional parameter space such that a number n parameters span an n-dimensional parameter space, where n is a natural number greater than or equal to two.

[0034] In particular, the permissible range is a multidimensional permissible range. For example, the permissible range has the same dimension as the multidimensional parameter space spanned by the monitored parameters.

[0035] For example, if four parameters are monitored (n=4), a four-dimensional parameter space is considered. Furthermore, the allowed range in this case is, for example, a allowed four-dimensional range within the four-dimensional parameter space.

[0036] For example, the allowed range is determined based on the provided allowed value ranges for the two or more monitored parameters, so that for each monitored parameter its corresponding (one-dimensional) allowed value range is taken into account.

[0037] Based on the received current and / or determined future values ​​of the two or more parameters, a current and / or future state point of the system consisting of the nanomanipulator and sample is determined in the multidimensional parameter space. With a number n of monitored parameters spanning an n-dimensional monitored parameter space, a current and / or future state point is a point in the n-dimensional space that is given (e.g., uniquely defined) by a number n of coordinates.

[0038] By determining whether the current and / or future state point is within the allowed range of the n-dimensional parameter space and by automatically initiating countermeasures when it is determined that the current and / or future state point is outside the allowed range, processing of the sample with the nanomanipulator can be simplified for a user.

[0039] In embodiments, step e) can also be carried out depending on a length of stay outside the permitted area (e.g. in a warning area and / or a prohibited area).

[0040] For example, a movement of the measuring tip can only be stopped and / or the measuring tip can only be retracted perpendicular to the sample when it is determined that the state point outside the permitted area has been occupied for a predetermined dwell time. The permitted dwell time can vary for different areas outside the permitted area (e.g., warning area, prohibited area). In particular, a predetermined first dwell time for a stay in the warning area can be longer (e.g., 1 second) than a predetermined second dwell time for a stay in the prohibited area (e.g., 0.01 second).

[0041] According to one embodiment, the future values ​​of the two or more parameters are predicted based on a received user input and / or based on a determined drift movement of the measuring tip relative to the sample.

[0042] The future values ​​of the monitored two or more parameters can thus be determined, i.e. predicted, based on received user input, for example. User input is provided, for example, using a human-machine interface (HMI), such as a keyboard, mouse pointer, joystick, game controller, touch screen, or the like. By determining the future values ​​of the monitored two or more parameters based on received user input, a target position of the measuring tip entered by a user via the human-machine interface can be checked with regard to the monitored parameters.If executing the user input would cause the determined permissible range in the multidimensional parameter space to be exceeded, the movement of the measuring tip can be stopped, for example, and the user input cannot be executed or can only be executed partially. Alternatively, the measuring tip can be retracted relative to the sample so that the distance between the measuring tip and the sample surface is large enough that executing the user input is harmless.

[0043] The future values ​​of the monitored two or more parameters can, for example, also be determined, i.e. predicted, based on a detected drift movement of the measuring tip relative to the sample. This makes drift monitoring (English: drift guard) possible, e.g. even without user input. It is known that such drift movement 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 using a scanning electron microscope), whereby a force between the measuring tip and the sample is increased, leading to drift. So-called "creep" of the measuring tip when moving to a certain position on the sample is also known.

[0044] Drift of the measuring tip relative to the sample can be detected, for example, by image processing of repeated image acquisitions of the sample, in which both the measuring tip and a structure and / or marking (e.g., drift marker) of the sample are captured. If further drift would lead to leaving the permissible range in the multidimensional monitored parameter space, the movement of the measuring tip can be stopped and / or the measuring tip can be retracted from the sample.

[0045] According to a further embodiment, the method comprises: Determining a warning range in the multidimensional parameter space for the two or more parameters, Determine whether the current and / or future state point in the multidimensional parameter space lies within the determined warning range, and Controlling the positioning unit so that a movement of the measuring tip is slowed down and / or controlling a human-machine interface to issue a warning if it is determined that the current and / or future state point is within the determined warning range.

[0046] By determining the warning range, a buffer zone can be established between the permitted range and the forbidden range in the parameter space of the monitored parameters. This allows a user to be warned before the forbidden range is reached or to slow down a change in the nanomanipulator's control parameters, such as the speed at which the measuring tip is moved.

[0047] For example, in the method (e.g. predetermined) warning value ranges are provided for the two or more parameters (e.g. read and / or received from a storage unit) and the multi-dimensional warning range is determined based on the provided warning value ranges.

[0048] Alternatively, the multidimensional warning range can also be determined (e.g., calculated) based on the determined permitted range. For example, a core range (e.g., 90%) of the provided permitted value ranges can be used for all monitored parameters to determine the permitted multidimensional range. Furthermore, a marginal range (e.g., the remaining 10%) of the provided permitted value ranges can be used for all monitored parameters to determine the multidimensional warning range.

[0049] For example, the warning zone and / or a forbidden zone can also be determined based on a calculation of the probabilities with which damage to the sample and / or the nanomanipulator occurs at certain parameter values. The probability of this damage can depend strongly non-linearly on the parameter values.

[0050] The warning range is, in particular, a multidimensional warning range. For example, one dimension of the warning range is the same size as one dimension of the permitted range and one dimension of the monitored parameter space.

[0051] For example, the warning area is an area adjacent to the permitted area. The warning area is located between the permitted area and a prohibited area. For example, the warning area completely surrounds the permitted area in the multidimensional parameter space (e.g., completely).

[0052] In embodiments, the positioning unit of the nanomanipulator can also be controlled such that a state point of the monitored parameters is moved back from the warning range to the permitted range if it is determined that the current and / or future state point lies within the determined warning range.

[0053] According to a further embodiment, the permitted range, the warning range and / or a prohibited range of the multidimensional parameter space have discrete boundaries or the permitted range, the warning range and / or the prohibited range merge continuously into one another.

[0054] In a case where the permitted range, the warning range, and / or the prohibited range continuously merge into one another, a continuously variable safety map (damage probability map) can be defined in the multidimensional parameter space. For example, the permitted range, the warning range, and / or the prohibited range can be determined based on a calculation of the probability with which the sample and / or the measuring tip will be damaged. For example, a damage probability for each state point in the multidimensional parameter space or a safety level with regard to non-damage to the measuring tip and / or the sample can be calculated for each state point in the multidimensional parameter space, and the damage probability map or safety map can be determined in this way. The damage probability of a state point can, in particular, depend in a highly nonlinear manner on the values ​​of the monitored parameters.

[0055] In a case where the permitted area, the warning area, and / or the prohibited area continuously merge into one another, step e) can optionally be performed depending on the penetration depth into the warning area. For example, the speed at which the measuring tip is retracted from the sample in step e) can be greater the further a current state point has penetrated from the permitted area into the warning area.

[0056] The forbidden area is, in particular, a multidimensional forbidden area.

[0057] According to a further embodiment, the nanomanipulator has a cantilever that is movably attached to the positioning unit at its base end. Furthermore, the measuring tip is arranged at a free end of the cantilever. Furthermore, the two or more parameters of the nanomanipulator and / or the sample include: a position of the foot end of the boom relative to the positioning unit, a speed of the foot end of the boom relative to the positioning unit, a deflection of the free end of the cantilever in a z-direction which is arranged perpendicular to the sample, a rotation of the free end of the boom around an x-direction which is perpendicular to the z-direction, a bending of the measuring tip relative to the boom, and / or Position data of sample structures.

[0058] This allows for efficient monitoring of a multidimensional, complex parameter space with respect to process parameters of the nanomanipulator, e.g., the atomic force microscope, and / or the sample.

[0059] In particular, the position of the foot end of the boom relative to the positioning unit (e.g. in three spatial directions spanning a three-dimensional space), the speed of the foot end of the boom relative to the positioning unit (e.g. in the three spatial directions), the deflection (e.g. an extent of the deflection) of the boom at its free end in the z-direction, the twisting (e.g. an extent of the twisting) of the boom at its free end about the x-direction and / or the bending (e.g. an extent of the bending) of the measuring tip relative to the boom are recorded (e.g. measured).

[0060] The position of the foot end of the boom relative to the positioning unit and the speed of the foot end of the boom relative to the positioning unit can be adjusted, in particular, by controlling the positioning unit. Furthermore, current values ​​of the position and speed of the foot end of the boom relative to the positioning unit are provided, for example, by the positioning unit.

[0061] The deflection of the free end of the cantilever in the z-direction is caused by forces acting between the measuring tip and the sample. The deflection of the free end of the cantilever in the z-direction is also proportional to a spring constant of the cantilever. In particular, the cantilever bends to varying degrees when scanning the sample depending on the forces acting between the measuring tip and the sample. The extent of this bending or deflection of the free end of the cantilever in the z-direction can be detected, for example, using a light pointing device. The nanomanipulator, e.g., the atomic force microscope, and / or a higher-level device comprising the nanomanipulator, for example, has such a light pointing device.

[0062] The parameters of the nanomanipulator may, for example, also include a deflection of the free end of the cantilever in a direction that deviates from the z-direction (the direction perpendicular to the sample) by an angle of 30° or less, 20° or less, 10° or less, 5° or less, 3° or less, and / or 1° or less.

[0063] 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 onto the free end of the cantilever and, when the cantilever is in an undeflected position, is reflected from there into the center of the position-sensitive photodetector. The photodetector is divided into four regions, for example, "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.

[0064] For example, the z-direction is arranged perpendicular to a main extension plane of the sample.

[0065] Forces acting between the measuring tip and the sample can also cause the free end of the cantilever to twist around the x-direction. This can also be detected using the light pointer device described above.

[0066] In addition, interaction between the measuring tip and the sample (e.g., lateral movement of the measuring tip upon contact between the measuring tip and the sample) can lead to bending (i.e., elastic deformation) of the measuring tip relative to the cantilever. The extent of this bending of the measuring tip relative to the cantilever can be determined using image processing in acquired images (e.g., scanning electron microscope images, scanning ion microscope images) of the measuring tip.

[0067] In embodiments, the positioning unit can also comprise a stationary positioning component (which is, for example, attached to a housing of the nanomanipulator) and a positioning component that is movable relative to the stationary positioning component and to which the base end of the cantilever is fixedly attached. Then, a position of the base end of the cantilever can be moved together with the movable positioning component of the positioning unit. Furthermore, the position of the base end of the cantilever can be moved together with the movable positioning component relative to the stationary positioning component. In this case, the two or more parameters of the nanomanipulator include, for example, a position of the base end of the cantilever relative to the stationary positioning component of the positioning unit and / or a speed of the base end of the cantilever relative to the stationary positioning component of the positioning unit.

[0068] The two or more parameters of the nanomanipulator may additionally or instead include a spring constant of the cantilever, an opening angle of the measuring tip and / or a length of the measuring tip.

[0069] According to a further embodiment, the method further comprises: Receiving images of at least part of the sample taken with a scanning electron microscope, wherein the two or more parameters of the nanomanipulator and / or the sample comprise an amount of charge on a surface of the sample.

[0070] This allows the accumulation of charge caused by a high-energy electron beam on the sample surface to be monitored in the multidimensional parameter space.

[0071] In particular, the removal of particles from the sample with the nanomanipulator is usually monitored using a scanning electron microscope, which causes the aforementioned high electron beam dose on the sample surface.

[0072] In embodiments, the scanning electron microscope is controlled to stop capturing images of the at least a portion of the sample when it is determined that a current and / or future value of the amount of charge at the surface of the sample is outside an allowed range of values ​​for the amount of charge at the surface of the sample.

[0073] In embodiments, a human-machine interface is controlled to issue a request to a user to perform a discharge process (e.g., by means of a plasma source) of the sample surface when it is determined that a current and / or future value of the amount of charge at the surface of the sample is outside a permitted range of values ​​for the amount of charge at the surface of the sample.

[0074] According to a further embodiment, providing the permitted value ranges for the two or more parameters comprises providing and / or determining position data of structures of the sample.

[0075] The structures of the sample are, for example, absorber structures of a lithography mask.

[0076] For example, a main extension plane of the sample is an xy plane. The position data of sample structures define, for example, forbidden value ranges with respect to an x ​​position and a y position in the xy plane. For example, the xy positions on the sample surface where the structures are present are forbidden regions. For example, the xy positions on the sample surface where edges of the structures are present are forbidden regions. The xy positions on the sample surface where the structures are not present are thus permitted regions or permitted and (close to a respective structure edge) warning regions.

[0077] According to a further embodiment, determining the position data of the structures of the sample comprises: Receiving one or more images of at least a portion of the sample, and

[0078] Determining the position data of the structures of the sample by means of image analysis of the one or more received images and / or by means of edge detection of edges of the structures in the one or more received images.

[0079] In particular, the one or more images of the sample are received by an image recording device, e.g., a scanning electron microscope and / or a scanning ion microscope.

[0080] According to a further embodiment, determining the position data of the structures of the sample comprises: Receiving an image of at least a portion of the sample, wherein the image captures a defect-free region comprising a first portion of the structures and a defect-affected region comprising at least one defect and a second portion of the structures, and wherein a geometric shape of the first portion of the structures corresponds to (e.g., matches) a geometric shape of the second portion of the structures, Determining the geometric shape of the first section of the structures in the defect-free area by means of image analysis, and Determining the position data of the second section of the structures in the defect-affected area based on the determined geometric shape of the first section of the structures in the defect-free area.

[0081] This allows the detection of structures and the determination of their position data to advantageously take place in a defect-free area of ​​the sample. This allows the position data of the structures to be determined more precisely.

[0082] A defect is, for example, a particle (e.g. a foreign body).

[0083] According to a further embodiment, the method comprises: Receiving an image of at least part of the sample, Controlling a display device to display the image, Receiving a target position of the measuring tip in the image entered by a user using a graphic user interface, and Fully automatic control of the positioning unit to move the measuring tip to the target position.

[0084] This means that a user only needs to select (e.g. click) a target location in the captured image using the graphic user interface (e.g. a mouse pointer) and then the measuring tip is moved fully automatically to this target location.

[0085] For example, image processing functions such as pattern recognition can be applied to determine the measuring tip and its location in the captured image. Alternatively, a method such as that described in US Pat. No. 7,675,300 B2 can be used to identify the measuring tip and determine its position.

[0086] For example, multiple images of at least part of the sample can be captured and received. The images can be acquired at a high rate (video mode), for example, and image processing can be performed in real time.

[0087] According to a further embodiment, the method comprises: Determine whether a time period since receiving a last user input is greater than a threshold, and Fully automatic control of the positioning unit to move the measuring tip into the determined permitted range of the multidimensional parameter space if the time since receiving the last user input is greater than the threshold value.

[0088] This provides a deadman's switch. In particular, it can prevent the system from entering the warning zone and / or the prohibited zone.

[0089] The permissible range (safe range) is achieved, for example, by (i) activating the z-feedback and thus keeping the force between the measuring tip and the sample constant at a low force; (ii) retracting the measuring tip from the sample using a fine adjustment (e.g., by a few micrometers); (iii) retracting the measuring tip from the sample using a coarse adjustment (e.g., by 100 micrometers); and / or (iv) moving the sample stage away from the measuring tip (e.g., by a few millimeters).

[0090] According to a further embodiment, the method comprises: Receiving a plurality of images of at least a portion of the sample, wherein the images capture a structure and / or marking of the sample and the measuring tip, and Determining a drift movement of the measuring tip relative to the structure and / or the marking of the sample by image analysis of the received images, and / or Determining a drift correction based on the determined drift movement and / or based on predetermined model data, and Fully automatic control of the positioning unit to move the measuring tip according to the determined drift correction.

[0091] This allows drift movement due to thermal drift and / or charging of the sample surface to be corrected fully automatically without user control.

[0092] The marking is, for example, a drift marking of the sample.

[0093] For example, the model data in the case of thermal drift shows a linear model with a constant drift rate.

[0094] According to a further embodiment, the method comprises: Controlling an image recording device for recording a first image of a defective section of the sample, in which first structures of the sample and one or more defects of the sample are recorded, Controlling the image recording device to record a second image of a defect-free section of the sample in which second structures of the sample are detected, the geometric shape of which corresponds to a geometric shape of the first structures in the first image, Determining a difference image based on a subtraction of the second image from the first image, Determining position data of the one or more defects detected in the first image based on an image analysis of the difference image, and Controlling the image recording device to record a third image of a defective portion of the sample in which the one or more defects detected in the first image is / are arranged at a predetermined position in the image (e.g. in an image center).

[0095] The sample is, for example, a lithography mask for microlithography. The sample has, for example, a structural pattern for producing a specific type of semiconductor chip (die). This structural pattern is repeated several times on the lithography mask, for example, in order to produce several similar semiconductor chips (dice) using one and the same lithography mask. For example, the first structures in the first image are used to produce a first semiconductor chip, and the second structures in the second image are used to produce a second semiconductor chip of the same type. Since the first and second structures correspond to one another, they are eliminated when determining the difference image (“D2D” for “die to die”), so that the difference image contains no structures and the defect is imaged with greater contrast. Thus, a position of the defect can be determined more accurately based on the difference image.In addition, the highly precise determination of the defect's position allows a third image centered on the defect (e.g., a particle) to be captured fully automatically. This facilitates further processing by the user.

[0096] The image recording device is, for example, a scanning electron microscope.

[0097] For example, before controlling the image acquisition device to acquire the first and second images, "rough" position data of one or more defects (e.g., particles) of the sample are provided. Furthermore, based on these "rough" position data, the method steps proposed according to this embodiment determine more precise position data of one or more defects (e.g., particles) of the sample, which are in particular more precise than the "rough" initial position data.

[0098] Determining the difference image based on the subtraction of the second image from the first image comprises, for example, a mathematical subtraction of the second image from the first image. For example, the first and second images each have a two-dimensional arrangement of pixels and an intensity value assigned to each pixel. For example, the first and second images have the same number of pixels and the same arrangement of pixels. When mathematically subtracting the second image from the first image, for example, for each pixel of the first image, an intensity value of the corresponding pixel of the second image is subtracted (subtracted) from an intensity value assigned to that pixel. The difference between the two intensity values ​​results in an intensity value of a corresponding pixel of the difference image. In particular, the difference image has the same number of pixels and the same arrangement of pixels as the first and second images.

[0099] Furthermore, determining the difference image based on the subtraction of the second image from the first image may also comprise, for example, generating an image section of the first and / or second image, image registration of the first and second image, and / or applying an image filter to the first and / or second image.

[0100] In embodiments, the method comprises: Controlling an image recording device for recording one or more first images of at least a part of the sample in which a reference structure and one or more defects of the sample are recorded, Determining position data of the one or more defects detected in the one or more first images relative to the reference structure based on an image analysis, and Controlling the image recording device to record one or more second images of at least a part of the sample in which the one or more defects detected in the first image is / are arranged at a predetermined position in the image (e.g. in an image center) relative to the reference structure.

[0101] This allows a defect (e.g. a particle) to be automatically kept at a predetermined position in the image (e.g. in the center of the image) when images are repeatedly taken (particle tracking).

[0102] According to another embodiment, the nanomanipulator comprises a cantilever that is attached to the positioning unit at a fixed angle at its first end and has the measuring tip arranged at its second end. Furthermore, the sample is arranged on a rotatable sample stage. The method further comprises: Receiving an image of at least a part of the sample, wherein the image includes structures of the sample and a defect, Determining an access angle for the measuring tip to process the defect such that an access path with the access angle is free of structures of the sample, and Controlling the sample stage to rotate the sample stage based on the determined access angle such that the fixed angle of the measuring tip matches the access angle.

[0103] This allows an angle between the measuring tip and the sample to be set that is advantageous for processing the defect.

[0104] In particular, an access angle for the measuring tip for processing the defect is determined in such a way that a linear access path having the access angle is free of structures of the sample.

[0105] The access path is, for example, also a removal trajectory and / or part of a removal trajectory for removing a particle (as an example of a defect). The access path is, for example, arranged in the xy-plane, which is, for example, parallel to the main extension plane of the sample. The access path is, for example, a linear access path. The access angle also lies, for example, in the xy-plane. The access angle is, in particular, an angle between a first straight line parallel to the longitudinal direction of the cantilever and a second straight line parallel to the access path. The fixed angle at which the cantilever is attached to the positioning unit also lies, for example, in the xy-plane.

[0106] In particular, the nanomanipulator comprises a sample stage device with a holder, a sample stage movably mounted on the holder, and a further positioning unit for moving the sample stage relative to the holder. Furthermore, the further positioning unit for rotating the sample stage with the sample relative to the holder is controlled based on the determined access angle such that the fixed angle of the measuring tip matches the access angle.

[0107] The sample table is mounted on a holder so that it can rotate in the z-direction.

[0108] In embodiments, the nanomanipulator comprises a cantilever that is attached to the positioning unit at a fixed angle at its first end and has the measuring tip arranged at its second end. Furthermore, the sample is arranged on a rotatable sample stage. The method further comprises: Receiving an image of at least a part of the sample, wherein the image includes structures of the sample and a particle, Determining, based on the received image, a linear removal trajectory for the particle to remove the particle 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, and Controlling the sample stage to rotate the sample stage based on the determined distance trajectory such that the fixed angle of the measuring tip is arranged perpendicular to the distance trajectory.

[0109] This allows the particle to be removed along a trajectory parallel to a direction in which lateral forces can be detected.

[0110] For example, the distance trajectory is determined such that the distance trajectory on one side of the particle extends beyond the particle by twice the size of the particle. Additionally or instead, the distance trajectory is determined such that the distance trajectory on the other side of the particle extends beyond the particle by one and a half times the diameter of the measuring tip.

[0111] The distance trajectory, for example, is a trajectory in the xy-plane.

[0112] In embodiments, the method comprises: Receiving images of at least a part of the sample in which the measuring tip is captured, Controlling a display device to display the received images, Receiving user input from a user to change a magnification of the displayed images, and Controlling the positioning unit of the nanomanipulator to automatically change the speed of the measuring tip depending on the image scale.

[0113] If the probe tip is operated at a constant speed and a user zooms into the captured image (e.g., a scanning electron image) (i.e., increases the image scale), the perceived movement of the probe tip in the captured image may be too high for the user to meaningfully use a mouse pointer, joystick, or equivalent graphical user interface (GUI) tool. According to this embodiment, the probe tip speed is automatically adjusted depending on the image scale (i.e., the magnification of the displayed image), eliminating this task for the user.

[0114] In embodiments, the method comprises: Receiving a user input that indicates the start of a macro creation and specifies a macro control parameter for the macro creation, Receiving multiple macro user inputs to control the positioning unit of the nanomanipulator to move the measuring tip, Receiving user input indicating the end of macro creation, and Saving the macro control parameter and the macro user inputs associated with the macro control parameter.

[0115] In one example of macro creation, receiving multiple macro user inputs includes receiving a user input to move the measuring tip laterally and receiving a user input to retract the measuring tip perpendicular to the sample (move and lift). This allows a move-and-lift macro to be created for the combined movement of the measuring tip laterally to the sample and perpendicular to the sample away from the sample. By applying this move-and-lift macro, a user can bring the measuring tip closer to a particle on the sample, contact the particle with the measuring tip, and lift the particle while attached to the measuring tip, all with a single user input.

[0116] In embodiments, the method includes receiving user input from a game controller as an example of a graphical user interface. A game controller, for example, has many programmable buttons and joysticks. The game controller may also include adaptive triggers with haptic feedback via voice coil actuators that can change the resistance for a user as needed. For example, this can better adjust the optimal force between the probe tip and the sample surface.

[0117] The game controller can, for example, have multiple inputs, such as analog sticks, analog triggers, digital buttons, directional buttons, and capacitive touch pads with a click mechanism (e.g., dual shock). These inputs can be used for sample stage movement and tip movement (e.g., with adjusted speed using pressure-sensitive joysticks or buttons), control of a scanning electron microscope (e.g., magnification, focus, stigmator, scan strategies), and the like. Furthermore, the game controller can also provide feedback to the user. For example, the game controller can vibrate when the displacement signal (e.g., the cantilever displacement) reaches a threshold. Furthermore, a built-in light bar orA series of LEDs are used to display various information such as deflection signal, lateral signal, probe tip limits, probe tip status (approached, raised, retracted) and out of range.

[0118] The game controller may also include a gyroscope and / or an accelerometer. Data collected by these devices can be used to determine whether a user is showing signs of fatigue and needs a break.

[0119] The game controller may also include one or more microphone arrays and / or a headphone jack (e.g., a 3.5 mm stereo headphone jack). These devices can provide, for example, audible feedback.

[0120] In embodiments, the nanomanipulator comprises a cantilever that is movably attached to the positioning unit at its base end, with the measuring tip arranged at a free end of the cantilever. Furthermore, the method comprises: Receiving at least one scanning electron microscope image in which the measuring tip and / or the cantilever is / are at least partially captured, Determining one or more properties of the measuring tip and / or the boom by image analysis of the at least one received image, and Determine a type and / or status of the probe tip based on the determined property(ies) of the probe tip and / or boom.

[0121] When processing samples with the nanomanipulator, different types of measuring tips are typically used. Furthermore, measuring tips can change with use, for example, by becoming worn or dirty. The differences between the various measuring tips are usually so small that they cannot be detected with the naked eye or with an optical microscope.

[0122] By capturing at least one scanning electron microscope (SEM) image of the measuring tip and / or the cantilever, which has a very high spatial resolution, and image processing the SEM image, the type and / or status of the measuring tip can still be determined. This ensures that the correct measuring tip type is being used for processing the sample and / or that the measuring tip has a required status (e.g., low degree of wear). For example, it can be ensured that the correct measuring tip type is being used for a specific planned processing of the sample and / or that a measuring tip has a required status for a specific planned processing of the sample.

[0123] At least a part of the sample can optionally also be captured in the at least one received scanning electron microscope image.

[0124] In embodiments, the one or more properties of the measuring tip and / or the cantilever comprise a geometric shape of the measuring tip, an outer contour of the measuring tip, a length of the measuring tip, a taper angle of the measuring tip and / or a marking of the measuring tip and / or the cantilever.

[0125] In embodiments, the type of the measuring tip comprises a manufacturer type of the measuring tip.

[0126] In embodiments, the status of the measuring tip includes a degree of wear of the measuring tip and / or a contamination of the measuring tip.

[0127] In embodiments, the boom has a marking, in particular an identification mark and / or a QR code, determining the one or more properties of the measuring tip and / or the boom comprises detecting the marking by image analysis of the received image, and determining the type and / or status of the measuring tip comprises decoding the marking.

[0128] The marking is, for example, very small, so that it cannot be detected with the naked eye or with an optical microscope. The marking, in particular the identification marking and / or the QR code, has, for example, a size of 10 µm or smaller, 5 µm or smaller, 1 µm or smaller and / or 0.1 µm or smaller. The marking, in particular the identification marking and / or the QR code, has, for example, a marking structure with a structure size of 1 µm or smaller, 0.1 µm or smaller, 50 nm or smaller, 30 nm or smaller, 20 nm or smaller, 10 nm or smaller and / or 1 nm or smaller. The marking is, for example, a QR code with a pixel size of 1 µm or smaller, 0.1 µm or smaller, 50 nm or smaller, 30 nm or smaller, 20 nm or smaller, 10 nm or smaller and / or 1 nm or smaller.

[0129] The marking is arranged on the cantilever, for example, in such a way that it does not interact with the laser beam of the light pointing device of the nanomanipulator. The marking is arranged on the cantilever, for example, at a distance from an impact location and / or impact area of ​​the laser beam of the light pointing device, in which the laser beam impinges on the cantilever.

[0130] In embodiments, the type and / or status of the probe tip is determined based on the property(ies) determined by image analysis and based on predetermined data having properties associated with a plurality of different probe tips.

[0131] For example, the type and / or status of the measuring tip is determined based on a comparison of the property(ies) determined by image analysis with the predetermined data. The predetermined data comprises, for example, a database. The predetermined data comprises, for example, data entries for several different measuring tips with associated properties of the respective measuring tip. The associated properties of the respective measuring tip include, for example, a measuring tip type, usage data of the measuring tip (e.g., unused / used, frequency and / or duration of previous use, date of first use), status of the measuring tip (e.g., degree of wear, contamination, damage), X-ray data of the measuring tip (e.g., data of the measuring tip acquired using energy-dispersive X-ray spectroscopy (EDX)) and / or atomic force microscope resonance properties of the measuring tip.A resonance curve with respect to the atomic force microscope resonance properties of the measuring tip has, for example, a resonance frequency (i.e. a frequency of high and / or maximum oscillation amplitude), a quality factor (e.g. width of the resonance curve), a maximum oscillation amplitude upon excitation with a constant excitation amplitude and / or an occurrence of further peaks besides the resonance peak.

[0132] In embodiments, when determining the type and / or status of the measuring tip based on the property(ies) determined by image analysis and based on the predetermined data, it is determined whether the predetermined data includes a data entry for the measuring tip captured in the SEM image or for the measuring tip arranged on the cantilever captured in the SEM image (hereinafter referred to as the "captured measuring tip"). If it is determined that the predetermined data includes a data entry for the captured measuring tip, then the type and / or status of the captured measuring tip is determined, for example, based on a comparison of the determined property(ies) of the captured measuring tip with the data entry for the corresponding measuring tip in the predetermined data.

[0133] If it is determined that the predetermined data does not contain a data entry for the detected measuring tip, then, for example, a data entry for a similar measuring tip is determined in the predetermined data, which, for example, has the most similarities with the detected measuring tip within the group of measuring tips encompassed by the predetermined data in the form of data entries. The type and / or status of the detected measuring tip is then determined, for example, based on a comparison of the determined property(ies) of the measuring tip with the data entry for the measuring tip determined to be similar in the predetermined data.

[0134] In embodiments, the method comprises fully automatic adjustment of process parameters of the nanomanipulator based on the determined type and / or status of the measuring tip.

[0135] Examples of process parameters that are fully automatically set based on the determined type and / or status of the measuring tip are a speed at which the measuring tip is moved, retracting the measuring tip from the sample when it is moved near an edge, querying a position of a lowest point of the measuring tip from a database, sharpening or replacing the measuring tip in case of a contaminated and / or blunt measuring tip and selectively controlling a possible bending of the measuring tip depending on how sharp or blunt a measuring tip is.

[0136] For example, for sharp measuring tips (e.g., tips with a small apex curvature radius and / or a small aperture angle), the force between the measuring tip and the sample must not be as large as for blunt measuring tips (e.g., tips with a large apex curvature radius and / or a large aperture angle). This is because a large force will break a sharp measuring tip more easily. Furthermore, a sharp tip can damage the sample more easily. To limit the force, the approach movement of the measuring tip to the sample can be slowed down.

[0137] For example, in a case where the measuring tip is in contact with the sample and needs to be moved laterally up a step, the force is kept constant by a distance control loop. However, a force peak occurs directly at the step. A sharp measuring tip can be retracted as a precaution by moving it close to an edge.

[0138] For example, there are measuring tips where the lowest point is not visible in the SEM image. This is especially true for blunt measuring tips. If the position of the lowest point of the measuring tip is stored in a database, this information can be used to target a particle more precisely.

[0139] For example, if a probe tip is contaminated or blunt, it is unsuitable for removing small particles. In this case, an additional process step can be introduced before the probe tip picks up the particle, in which the probe tip is sharpened or replaced with a more suitable probe tip.

[0140] For example, very sharp and soft measuring tips can temporarily bend during particle manipulation. This can be observed using SEM images. Blunt measuring tips are not subject to this control.

[0141] In embodiments, the method comprises fully automatic control of the positioning unit for moving the measuring tip based on the determined type and / or status of the measuring tip.

[0142] In embodiments, the nanomanipulator comprises a loading device having a plurality of measuring tips and / or cantilevers with measuring tips arranged thereon, and comprises the method: Receiving user input regarding a particle removal strategy, Receiving predetermined data relating to measuring probes available in the charging device, Selecting a data entry for a measurement tip in the predetermined data based on the particle removal strategy, and Controlling the charging device to: automatically picking up a measuring tip and / or a boom with a measuring tip from the loading device, wherein the measuring tip corresponds to the data entry for a measuring tip selected in the predetermined data, and Attaching the mounted measuring tip to the boom and / or attaching the mounted boom with the measuring tip to the positioning unit.

[0143] The predetermined data are received, for example, from a storage device of the nanomanipulator and / or the charging device.

[0144] According to a further aspect, a computer program product is proposed which comprises instructions which, when the program is executed by at least one computer, cause the computer to carry out the method described above.

[0145] A computer program product, such as a computer program means, can be provided or delivered, for example, as a storage medium, such as a memory card, USB stick, CD-ROM, DVD, or in the form of a downloadable file from a server in a network. This can be done, for example, in a wireless communications network by transmitting a corresponding file with the computer program product or the computer program means.

[0146] According to a further aspect, a device for processing a sample is proposed. The device comprises: a nanomanipulator with a measuring tip for processing the sample and a positioning unit for moving the measuring tip, and a control device configured to carry out the method described above.

[0147] 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 designed as a device or as part of a device, for example, as a computer or a microprocessor. In a software implementation, the respective unit can be designed as a computer program product, as a function, as a routine, as part of a program code, or as an executable object. Furthermore, the corresponding unit can also be designed as part of a higher-level control system of the nanomanipulator.

[0148] "One" in this case is not necessarily limited to a single element. Rather, multiple elements, such as two, three, or more, may also be included. Any other counting term used here should not be understood as implying a limitation to the exact number of elements stated. Rather, numerical deviations upwards and downwards are possible, unless otherwise stated.

[0149] The embodiments and features described for the method apply accordingly to the proposed computer program product and the device and vice versa.

[0150] Further possible implementations of the invention also include combinations of features or embodiments described above or below with respect to the exemplary embodiments that are not explicitly mentioned. In this case, the person skilled in the art will also add individual aspects as improvements or additions to the respective basic form of the invention.

[0151] 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 is explained in more detail below using preferred embodiments with reference to the accompanying figures. Fig. 1 shows an apparatus for analyzing and / or processing a sample according to an embodiment; Fig. 2 shows a picture of a section of a device made with the Fig. 1 sample to be processed according to one embodiment; Fig. 3 shows a cross section of Fig. 2 along line III-III; Fig. 4 shows an enlarged section of the device from Fig. 1 together with a light pointer device according to an embodiment; Fig. Figure 5 illustrates an example of a two-dimensional parameter space of the device and / or the sample from Fig. 1, where a determined allowed range in the parameter space is marked; Fig. 6 shows a view similar Fig. 5, wherein a determined permissible range and a warning range are marked in the parameter space; Fig. 7 shows a view similar Fig. 6, whereby the determined permitted area and the warning area merge continuously into one another; Fig. 8 shows a device made with Fig. 1 sample to be processed in cross-section, with charges accumulated on one surface of the sample; Fig. 9 illustrates a drift movement of a measuring tip of the device from Fig. 1 relative to a sample to be processed according to an embodiment; Fig. 10 illustrates edge detection of structures of a device provided with the Fig. 1 sample to be processed according to one embodiment; Fig. 11 illustrates a determination of position data of structures of a device provided with the device of Fig. 1 sample to be processed according to one embodiment; Fig. 12 illustrates a time period since a last user input to control the device from Fig. 1; Fig. 13 illustrates a determination of position data of a defect of a device provided with the device of Fig. 1 sample to be processed according to one embodiment; Fig. 14 shows an image of a section of the sample taken with an image recording device from Fig. 13, wherein the image recording device is directed to the Fig. 13 determined position of the defect was centered; Fig. 15 illustrates determining a favorable access path for a measuring tip of the device from Fig. 1 to remove a defect in the sample; and Fig. 16 shows a flow diagram of a computer-implemented method for processing a sample with the device of Fig. 1 according to one embodiment.

[0152] In the figures, identical or functionally equivalent elements are provided with the same reference numerals unless otherwise indicated. Furthermore, it should be noted that the representations in the figures are not necessarily to scale.

[0153] Fig. 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 cantilever 108, which is movably attached to a positioning unit 110 (movement unit). In particular, the cantilever 108 has a first end 112 (foot end 112), to which the cantilever 108 is movably attached to the positioning unit 110. Furthermore, the cantilever 108 has a second end 114 (free end 114), at which the measuring tip 106 is arranged. Using the positioning unit 110, the measuring tip 106 can be moved in three spatial directions x, y, z (translation movement in x - , y - and z-direction.)

[0154] Although not shown in the figures, the positioning unit 110 can also have a stationary positioning component (which is, for example, attached to a housing 116 of the device 100) and a positioning component that is movable relative to the stationary positioning component and to which the base end 112 of the boom 108 is fixedly attached. In this case, the base end 112 of the boom 108 can be moved together with the movable positioning component of the positioning unit 110 relative to the stationary positioning component of the positioning unit 110. However, the following describes an embodiment in which the base end 112 of the boom 108 is movably attached to the positioning unit 110.

[0155] The device 100 comprises a housing 116, which is pressurized, for example, by means of a vacuum pump 118 to a residual gas pressure of 1 - 10 -10 mBar, e.g., 10 -5 - 10 -9mBar, is evacuatable. The atomic force microscope 104 is arranged in the housing 116. Furthermore, a sample table 120 is provided for holding the sample 102. The sample table 120 is preferably held by the housing 116 by means of a holder 122. The sample table 110 can further comprise a further positioning unit (not shown), by means of which the sample table 120 can be moved, for example, in the three spatial directions x, y and z and, for example, about at least one axis (e.g., the z-axis in Fig. 1) is rotatable.

[0156] In addition, an electron column 124 is arranged in the housing 116. The electron column 124 is configured to provide an electron beam 126. The electron column 124 can be designed, in particular, as an electron microscope and can be used to monitor the capture of a particle 128 (see Fig. 2) can be used with the measuring tip 106.

[0157] In conjunction with a process gas supply unit 130, the electron column 124 can also be used to perform particle beam-induced machining processes on the sample 102. For this purpose, a process gas 132 is supplied, for example, by means of the process gas supply unit 130, which is irradiated with the particle beam 126.

[0158] With the measuring tip 106, a particle 128 ( Fig. 2). For this purpose, the measuring tip 106 is moved accordingly, for example, using the positioning unit 110. The sample stage 120 can also be moved using its additional positioning unit (not shown) to support this process. The picking up of the particle 128 by the measuring tip 106 is monitored live, in particular, using the electron microscope 124.

[0159] Subsequently, the measuring tip 106 is moved by means of the positioning unit 110 to a storage unit (not shown), where the particle 128 is transferred from the measuring tip 106 to the storage unit.

[0160] In Fig. 1 also shows a control device 136 for controlling the atomic force microscope 104, the sample stage 120, the electron microscope 124, and / or the process gas supply unit 130. A human-machine interface 138 can be provided as part of the control device 136 or connected to the control device 136 for data transfer in a wired or wireless manner. The human-machine interface 138 includes, for example, a display device 140, a speaker (not shown), a keyboard 142, a mouse pointer 144, a joystick, a game controller (not shown), or the like.

[0161] The illustrated device 100 includes a number of optional elements that are not mandatory. These include, in particular, the housing 116, the vacuum pump 118, the sample stage 120, the electron column 124, the process gas supply unit 130, and the human-machine interface 138.

[0162] In Fig. 2 shows an image 146 (e.g., a scanning electron microscope image 146, in short: SEM image 146) of a section of an exemplary sample 102. Fig. 3 shows the Fig. 2 as Figure 146 shown section of sample 102 in a cross-sectional view along line III-III in Fig. 2. The sample 102 has, for example, structures 148 (e.g., absorber structures 148) with intervening trenches 150. Furthermore, an exemplary particle 128 is shown on the sample 102, which lies in one of the trenches 150 at the edge of one of the absorber structures 148 and must be removed. The reference numeral 152 in Fig. 3 indicates a substrate of sample 102.

[0163] Removing particles 128 using the atomic force microscope 104 requires manipulation of the measuring tip 106 with a precision on the order of nanometers. It may be necessary to approach a particle 128 many times with the user-controlled measuring tip 106 and monitor the process in the SEM image 146 until the particle 128 finally adheres to the measuring tip 106 and can be removed from the sample 102. This is a tedious task, where small errors by a user can easily lead to damage or destruction of the measuring tip 106 and / or the sample 102.

[0164] In the following, with reference to the Fig. 1 to 16, a computer-implemented method for processing a sample 102 with an atomic force microscope 104 is described.

[0165] The procedure enables automatic and simultaneous monitoring of many parameters A1 to A6 ( Fig. 2, Fig. 3, Fig. 5) of the atomic force microscope 104 and / or the sample 102 using the control device 136 ( Fig. 1). In particular, the method can be used to automatically monitor process parameters A1, A2 of the atomic force microscope 104. The process parameters A1, A2 of the atomic force microscope 104 are, for example, a position Px, Py, Pz ( Fig. 4) of the foot end 112 of the boom 108 in the three spatial directions x, y, z and / or by a deflection D of the boom 108 at its free end 114 in the z-direction.

[0166] In addition, the method can be used to automatically monitor parameters A3 to A5 of the sample 102. The parameters A3 to A5 of the sample 102 are, for example, position data of structures 148 ( Fig. 2, Fig. 3) the sample 102, such as x - , y - and z-coordinates of structures 148.

[0167] In Fig. 4 is an enlarged view of the atomic force microscope 104 of Fig. 1 shown.

[0168] The parameters A1 to A6 monitored in the method include, for example, two or more of the parameters A1 to A6 of the atomic force microscope 104 and the sample 102 described below.

[0169] The method can be used, for example, to monitor a position Px, Py, Pz of the base end 112 of the boom 108 relative to the positioning unit 110. Furthermore, a speed Vx, Vy, Vz of the base end 112 of the boom 108 relative to the positioning unit 110 can also be monitored. The position Px, Py, Pz and the speed Vx, Vy, Vz of the base end 112 of the boom 108 relative to the positioning unit 110 in the three spatial directions x, y, z are set, in particular, using the positioning unit 110. Current values ​​of these parameters Px, Py, Pz, Vx, Vy, and Vz are provided, for example, by the positioning unit 110 and / or detected using position sensors, speed sensors, and / or acceleration sensors (not shown).

[0170] The method can also be used, for example, to determine a deflection D ( Fig. 4) of the free end 114 of the cantilever 108 in the z-direction. The z-direction is perpendicular to the sample 102, in particular perpendicular to a main extension plane E (xy-plane in Fig. 2) of the sample 102. The deflection D of the free end 114 of the cantilever 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 cantilever 108. Thus, by detecting the deflection D, a force acting on the cantilever 108 in the z-direction can be determined.

[0171] Due to forces acting between the measuring tip 106 and the sample 102, a rotation R (twisting R, see Fig. 4) of the free end 114 of the boom 108 around the x-direction. This rotation R can also be monitored using the method proposed here.

[0172] The atomic force microscope 104 has, for example, a light pointer device 154 for detecting an amount of deflection D of the free end 114 of the cantilever 108 in the z-direction, as shown in Fig. 4. The light pointer device 154 can also be used to detect an amount of rotation R of the free end 114 of the boom 108 about the x-direction.

[0173] The light pointer device 154 comprises, for example, a laser source 156 and a position-sensitive photodetector 158. A laser beam 160 emitted by the laser source 156 is directed onto the free end 114 of the cantilever 108 (cantilever 108) and reflected from there onto the photodetector 158. The photodetector 158 has, for example, four photosensitive regions ul, ur, bl, and br. In an undeflected position of the cantilever 108, the laser beam 160, 162 is reflected into the center of the photodetector 156, as shown in Fig. 4. However, if the cantilever 108 is deflected in the positive or negative z-direction (deflection D), the reflected laser beam 162 travels on the photodetector 158 like a light pointer. By measuring the received intensities in the four areas ul, ur, bl, and br of the photodetector 158, vertical and horizontal deflection signals (deflection 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.

[0174] The method can also be used, for example, to measure a bending B ( Fig. 4) of the measuring tip 106 relative to the cantilever 108 can be monitored. In particular, interaction of the measuring tip 106 with the sample 102 can lead to a bending B (ie an elastic deformation) of the measuring tip 106 relative to the cantilever 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. 4) bend with simultaneous contact of the measuring tip 106 with the sample 102. The extent of this bending B of the measuring tip 106 can be determined by image processing in recorded images 146 (e.g., SEM images 146) of the measuring tip 106.

[0175] Furthermore, the method can also be used to automatically monitor parameters A3 to A6 of the sample 102. The parameters A3 to A6 of the sample 102 include, for example, position data A3 to A5 of structures 148 ( Fig. 2, Fig. 3) of sample 102. The position data A3 to A5 are, for example, x- and y-coordinates of the structures 148 ( Fig. 2) and / or a height A5 of the structures 148 in the z-direction ( Fig. 3). In addition, a charge quantity Q (A6) on the surface 134 of the sample 102 can be monitored ( Fig. 8).

[0176] By monitoring two or more of the above-mentioned parameters A1 to A6 of the atomic force microscope 104 and / or the sample 102, a multidimensional parameter space 164 ( Fig. 5) be monitored efficiently.

[0177] In a first step S1 of the method, permissible value ranges are provided for two or more parameters A1 to A6 of the atomic force microscope 104 and / or the sample 102. The two or more parameters A1 to A6 span a multidimensional parameter space 164.

[0178] In Fig. Figure 5 illustrates the monitoring of two parameters A1, A2 (e.g., the Px and Py positions of the foot end 112 of the boom). The two parameters A1, A2 span a two-dimensional parameter space 164.

[0179] Although not shown in the figures, preferably more than two parameters A1 to A6 are monitored. For example, the position and velocity of the base end 112 of the cantilever 108 in all three spatial directions x, y, z (corresponding to six parameters), the deflection D and rotation R of the free end 114 of the cantilever 108 (corresponding to two further parameters), the bending B of the measuring tip 106 (corresponding to one further parameter), the position A3, A4, A5 of the structures 148 of the sample 102 in three spatial directions x, y, z (corresponding to three further parameters), and the amount of charge Q on the sample surface 134 (corresponding to one further parameter) can be monitored simultaneously. In this example, the method can be used to monitor a thirteen-dimensional parameter space.

[0180] The provided permitted value ranges are, for example, predetermined permitted value ranges that are stored in a memory device (not shown) of the control device 136 and / or received by the control device 136. The permitted value ranges for the two or more parameters A1 to A6 are, in particular, each one-dimensional value ranges.

[0181] In a second step S2 of the method, a permissible range 166 is determined in the multidimensional parameter space 164 based on the provided permissible value ranges for the two or more parameters A1 to A6. The permissible range 166 can, for example, also be determined based on the permissible value ranges for the two or more parameters by calculating a probability that the sample 102 will be damaged.

[0182] The permitted area 166 is determined in step S2, for example, by the control device 136. Furthermore, the permitted area 166 is determined in step S2, for example, fully automatically, ie, without user intervention.

[0183] In Fig. 5, the determined permissible area 166 has a polygonal shape. In other examples, a determined permissible area 166 may also have a different shape. Furthermore, a dimension of the permissible area 166 is, for example, the same size as a dimension of the monitored parameter space 164 (in the example of Fig. 5 two-dimensional).

[0184] The reference number 168 in Fig. 5 indicates a forbidden area in the monitored parameter space 164.

[0185] In an optional third step S3 of the method, a warning area 170 ( Fig. 6) in the parameter space 164. The warning area 170 is located in particular between the permitted area 166 and the prohibited area 168'.

[0186] In a fourth step S4 of the process, current values ​​Z1, Z2 ( Fig. 5) of the two or more monitored parameters A1 to A6 are received and / or future values ​​Z'1, Z'2 of the two or more parameters A1 to A6 are determined.

[0187] The current values ​​Z1, Z2 of the two or more monitored parameters A1 to A6 are obtained, for example, from the positioning unit 110, the light pointer device 154 or based on image processing of images 146 of the scanning electron microscope 124.

[0188] The future values ​​Z'1, Z'2 of the two or more parameters A1 to A6 are predicted, for example, based on a received user input G. A user input G is provided, for example, using the human-machine interface 138 ( Fig. 1). For example, a target position T ( Fig. 2) the measuring tip 106 is checked with regard to the monitored parameters A1 to A6.

[0189] The future values ​​Z'1, Z'2 of the two or more parameters A1 to A6 can, for example, additionally or instead be predicted based on a determined drift movement 172 of the measuring tip 106 relative to the sample 202, as in Fig. 9 illustrates. Fig. 9 shows an image 246 of a section of a sample 202 in which the measuring tip 106 and a structure 248 of the sample 202 are captured. In Fig. 9, a position of the measuring tip 106' after a drift movement 172 of the measuring tip 106, 106' (e.g. due to thermal drift) is illustrated with dashed lines.

[0190] In a fifth step S5 of the method, a corresponding current state point Z or future state point Z' in the multidimensional parameter space 164 is determined based on the current values ​​Z1, Z2 and / or the future values ​​Z'1, Z'2 ( Fig. 5). In addition, in step S5 it is determined whether the current and / or future state point Z, Z' lies outside the permitted range 166.

[0191] The state point Z, Z' is determined in step S5, for example, by the control device 136. Furthermore, the state point Z, Z' is determined in S5, in particular, fully automatically.

[0192] In the Fig. In the example shown in Figure 5, the determined current state point Z lies within the permitted range 166. Furthermore, the determined future state point Z' lies outside the permitted range 166, in particular within the forbidden range 168.

[0193] If the optional step S3 has been executed, in which in addition to the permitted area 166 a warning area 170 ( Fig. 6) is determined, then the following optional steps S6 and S7 are also executed.

[0194] In an optional sixth step S6 of the method, it is determined whether the current and / or future state point Z, Z', Z'' lies within the determined warning range 170.

[0195] In an optional seventh step S7 of the method, the positioning unit 110 ( Fig. 1) is controlled so that a movement of the measuring tip 106 is slowed down if it is determined in step S6 that the current and / or future state point Z, Z', Z'' lies within the determined warning range 170.

[0196] Additionally or instead, in step S7, the human-machine interface 138 can also be controlled to output a warning to a user if it is determined in step S6 that the current and / or future state point Z, Z', Z'' lies within the determined warning range 170.

[0197] In an eighth step S8 of the method, the positioning unit 110 is automatically stopped to stop a movement of the measuring tip 106 (e.g. stopping a lateral movement of the measuring tip 106, ie stopping a movement of the foot end 112 of the boom 108 in the x and y directions in Fig. 4) and / or to retract the measuring tip 106 with respect to the sample 102 (ie moving the foot end 112 of the cantilever 108 in the positive z-direction in Fig. 4) is triggered when it is determined that the current and / or future state point Z, Z', Z'' lies outside the permitted range 166, e.g., within the warning range 170 and / or the prohibited range 168, 168''. The triggering in step S8 is performed, for example, fully automatically by the control device 138.

[0198] By stopping a movement of the measuring tip 106 and / or retracting the measuring tip 106 with respect to the sample 102, penetration into the prohibited area 168, 168' can be prevented fully automatically, i.e., without user intervention. This can prevent damage to the measuring tip 106 and / or the sample 102.

[0199] The determined permitted area 166, the determined warning area 170 and / or the determined forbidden area 168, 168' of the monitored multidimensional parameter space 164 may have discrete boundaries G1, G2, as shown in the Fig. 5 and Fig. 6 shown.

[0200] Alternatively, the determined permitted area 166'', the determined warning area 170'' and / or the determined prohibited area 168'' can also merge continuously into one another, as in Fig. 7. For example, the permitted area 166'', the warning area 170'', and / or the prohibited area 168'' can be determined based on a calculation of a probability that the sample 102 will be damaged (damage probability). For example, depending on a damage probability (e.g., a damage probability that is greater than a predetermined threshold), a warning can be issued and / or the positioning unit 110 can be controlled to stop a movement of the measuring tip 106 and / or to retract the measuring tip 106 with respect to the sample 102. For example, the positioning unit 110 can be controlled depending on the damage probability such that the speed at which the measuring tip 106 is retracted from the sample 102 is greater, the greater the damage probability.

[0201] The method may optionally provide for one or more images 146 ( Fig. 2) at least a part of the sample 102 with an image recording device, such as the scanning electron microscope 124 ( Fig. 1) to be recorded.

[0202] The electron beam 126 used and a high electron beam dose applied can lead to a charge accumulation Q on the sample surface 134, as shown in Fig. 8 shown.

[0203] In the proposed method, it can therefore optionally be provided that one of the monitored parameters A1 to A6 of the atomic force microscope 104 and / or the sample 102 is a charge quantity Q on the surface 134 of the sample 102. If it is determined in step S5 that a current and / or future value of the charge quantity Q on the sample surface 134 lies outside a permissible value range, then the scanning electron microscope 124 can optionally be controlled to stop recording images 146 of the sample 102, and / or the human-machine interface 138 can be controlled to issue a request to a user to perform a discharge process on the sample surface 134.

[0204] Furthermore, in the method in step S1, it can optionally be provided to provide the permitted value ranges or a part of the permitted value ranges for the two or more monitored parameters A1 to A6 by position data A3 to A5 of structures 148 of the sample 102 ( Fig. 2, Fig. 3) be provided and / or determined.

[0205] For example, the position data A3 to A5 of the structures 148 of the sample 102 can be determined by image analysis of the one or more received images 146 of at least a portion of the sample 102.

[0206] Fig. 10 shows an example in which position data A3 to A5 of structures 348 of a sample 302 are determined by analyzing an image 346 (e.g., SEM image 346) of at least a portion of the sample 302. In Fig. 10, during image analysis, edge detection of edges K of structures 348 in image 346 is performed. Edges K of structures 348 of a sample 302 often appear as the brightest elements in SEM images 346, so that their position in the x- and y-directions on the sample 302 can be easily determined in a SEM image 346.

[0207] Fig. 11 illustrates a further example in which position data A3 to A5 of structures 448 of a sample 402 are determined by analyzing an image 446 (e.g., SEM image 446) of at least a portion of the sample 402. In the example of Fig. 11, there is a defect 428 (e.g., a particle 428) on the sample 402. The presence of one or more such defects 428 (e.g., particles 428) in the region of structures 448 of the sample 402 can make it difficult to detect and localize the structures 448. Therefore, in the example of Fig. 11, it is provided that the control device 136 ( Fig. 1) receives an image 446 of at least a portion of the sample 402, in which a defect-free region 174 and a defect-affected region 176 are captured. In particular, a first portion 178 of the structures 448 is captured in the defect-free region 174. Furthermore, at least one defect 428 (e.g., particle 428) and a second portion 180 of the structures 448 are captured in the defect-affected region 176. Furthermore, a geometric shape 182 of the first portion 178 of the structures 448 corresponds to a geometric shape 184 of the second portion 180 of the structures 448.

[0208] The defect-free region 174 allows for a better and more precise determination of the structures 448. Therefore, the geometric shape 182 of the first section 178 of the structures 448 in the defect-free region 174 of the image 446 is first determined by image analysis. Subsequently, the geometric shape 182 of the structures 178 determined for the defect-free region 174 of the sample 402 can be transferred to the defective region 176 of the sample 402. In particular, position data A3, A4 (e.g., the x and y positions) of the second section 180 of the structures 448 in the defective region 176 of the sample 402 can then be determined based on the determined geometric shape 182 of the first section 178 of the structures 448 in the defect-free region 174 of the image 446.

[0209] Optionally, the proposed method can also automatically approach a target position T ( Fig. 2) in an image 146 (e.g., SEM image 146). In particular, the automatic approach to the target position T is based on a target position T entered by a user via a graphic user interface 144. The graphic user interface 144 can, for example, be a mouse pointer 144 ( Fig. 1) or a joystick, game controller (not shown) or the like. For this purpose, the control device 136 receives an image 146 ( Fig. 2) at least a part of the sample 102 and controls a display device 140 ( Fig. 1) for displaying the received image 146. A user viewing the image 146 on the display device 140 can mark (e.g., click) a target position T for the measuring tip 106 using the graphic user interface 144. The control device 136 then receives the target position T of the measuring tip 106 in the image 146 entered by the user using the graphic user interface 144. The positioning unit 110 of the atomic force microscope 104 is then fully automatically controlled by the control device 136 such that the measuring tip 106 is moved to the target position T.

[0210] Optionally, the proposed method can also include a dead man function, in which a time period Δt since receiving a last user input G is monitored, as in Fig. 12. In Fig. 12 shows a time t in the form of a timeline. At time t1, in the example of Fig. 12 the last user input G. For example, at time t2, the control device 136 checks the time period Δt since receiving the last user input G. If the control device 136 determines that the time period Δt is greater than a predetermined threshold value Th (a predetermined time period Th), the dead man function is activated. In particular, the control device 136 then fully automatically controls the positioning unit 110 of the atomic force microscope 104 to move the measuring tip 106 into the determined permissible range 166, 166'' ( Fig. 5 to 7) of the multidimensional parameter space 164 and / or into a predetermined safety state C ( Fig. 6) to spend.

[0211] Optionally, the proposed method can also include a fully automatic drift correction, as described in Fig. 9. For this purpose, the control device 136 receives a plurality of images 246 of at least a portion of the sample 202. In the images 246, a structure 248 and / or marking of the sample 202 and the measuring tip 106 are captured. For example, due to thermal drift, the position of the measuring tip 106 relative to the structure / marking 248 can change over time. Fig. 9 illustrates a position of the measuring tip 106' after a drift movement 172 of the measuring tip 106, 106' has occurred with dashed lines. The control device 136 determines the drift movement 172 of the measuring tip 106 relative to the structure / marking 248 by analyzing the received images 246. Based on the determined drift movement 172, the control device 136 then determines a drift correction 172' and controls the positioning unit 110 fully automatically to move the measuring tip 106, 106' according to the determined drift correction 172'.

[0212] Optionally, fully automatic drift correction can also be performed using predefined model data—in addition to or instead of the described image analysis. For example, thermal drift can be approximated using a linear model.

[0213] Optionally, the proposed method can also provide fully automatic particle detection and image centering, as described in Fig. 13 and Fig. 14. For this purpose, the control device 136 controls an image recording device 124 (e.g., the scanning electron microscope 124, Fig. 1) to acquire a first image 546 of a defect-affected section 186 of a sample 502. First structures 188 of the sample 502 and one or more defects 528 are captured in the first image 546. Furthermore, the control device 136 controls the image acquisition device 124 to acquire a second image 546' of a defect-free section 190 of the sample 502. Second structures 192 of the sample 502 are captured in the second image 546', the geometric shape 196 of which corresponds to a geometric shape 194 of the first structures 188 in the first image 546.

[0214] An example in which the geometric shape 194 of first structures 188 of a sample 502 corresponds to the geometric shape 196 of second structures 192 of the sample 502 is that the first and second structures 188, 192 are part of a repeating pattern formed by structures 188, 192 of the sample 502. Another example in which the geometric shape 194 of first structures 188 of a sample 502 corresponds to the geometric shape 196 of second structures 192 of the same sample 502 is that multiple semiconductor chips of the same type are produced using one and the same sample 502 (e.g., a lithography mask 502). For example, in this case, the first structures 188 in the first image 546 serve to produce a first semiconductor chip (die) and the second structures 192 in the second image 546' serve to produce a second semiconductor chip of the same type.

[0215] In the next step, the control device 136 determines a difference image 546'' by subtracting the second image 546' from the first image 546. Since the first and second structures 188, 192 correspond to each other (ie, have the same geometric shape 194, 196), they are eliminated when determining the difference image 546'', so that no structures 188, 192 can be seen in the difference image 546''. In addition, the defect 528 is imaged with greater contrast in the difference image 546''. Thus, a position P P of the defect 528 based on the difference image 546'' can be determined more accurately. Therefore, position data P P of the one or more defects 528 detected in the first image 546 based on an image analysis of the difference image 546''.

[0216] Then, the image recording device 124 is controlled to record a third image 546''' of a defective portion 198 of the sample 502 such that the defect 528 is arranged at a predetermined position (e.g., in the image center M) in the third image 546'''.

[0217] Optionally, the proposed method can also provide for a fully automatic determination of an access angle β for a specific particle 628, as in Fig. 15. The background is that the boom 108 is arranged at a fixed angle α relative to the positioning unit 110 (in the example of Fig. 15, the angle α is zero). Thus, the orientation of the measuring tip 106 relative to the boom 108 and the positioning unit 110 is fixed. Now, as in Fig. 15 above, a particle 628, from the perspective of the measuring tip 106, may be arranged in the shadow of structures 648 of the sample 602 in such a way that direct access for the measuring tip 106 is blocked by the structures 648.

[0218] Then, the control device 136 can control an image recording device 124 (e.g., the scanning electron microscope 124) to record an image 646 of at least a portion of the sample 602, in which the structures 648 of the sample 602 and the particle 628 are captured. Next, the control device 136 can determine a possible access angle β for the measuring tip 106 for processing the particle 628 such that an access path W with the access angle β is free of structures 648 of the sample 602. The control device 136 can then control a positioning unit (not shown) of the sample stage 120 ( Fig. 1) to rotate the sample stage 120 about the z-axis. In particular, the positioning unit (not shown) of the sample stage 120 is controlled based on the determined access angle β such that the fixed angle α of the measuring tip 106 matches the access angle β. Thus, as in Fig. 15 below, the measuring tip 106 can access the particle 628 without any obstacles.

[0219] Consequently, the method described above allows, on the one hand, a high-dimensional parameter space 164 to be fully automatically monitored with respect to process parameters A1 to A6 of the atomic force microscope 104 and / or properties of the sample 102. This can prevent damage to the atomic force microscope 104 (e.g., the measuring tip 106) and the sample 102. Furthermore, as described above, various fully automatic controls are optionally possible via the control device 136 of the device 110, which allow a sample 102 to be processed more safely and easily on nanometer scales using the atomic force microscope 104.

[0220] Although the present invention has been described using exemplary embodiments, it can be modified in many ways. LIST OF REFERENCE SYMBOLS 100 device 102 Sample 104 Nanomanipulator (atomic force microscope) 106, 106' measuring tip 108 cantilever 110 Positioning unit 112 End 114 End 116 housings 118 Pump 120 sample table 122 bracket 124 electron column 126 electron beam 128 Defect (particle) 130 Process gas supply unit 132 Process gas 134 Surface 136 Control device 138 Human-machine interface 140 Display device 142 Keyboard 144 mouse pointers 146 Image 148 Structure 150 trenches 152 Substrat 154 Light pointer device 156 Laser source 158 Photodetector 160 laser beam 162 laser beam 164 Parameter space 166, 166'' range 168, 168', 168'' area 170, 170'' range 172 Drift movement 172' drift correction 174 Area 176 Area Section 178 Section 180 182 Shape 184 Shape Section 186 188 Structure Section 190 192 Structure 194 Shape 196 Shape Section 198 202 Sample 246 Image 248 Structure 302 Sample 346 Image 348 Structure 402 Sample 428 Defect (particle) 448 Structure 502 Sample 528 Defect (particle) 546, 546', 546'', 546''' Image 602 Sample 628 Defect (particle) 646 Image 648 Structure A1-A6 parameters α angle bl area br area B Bending β angle C Security status D Deflection Δt duration E Level G User input G1, G2 border K edge M Middle Px, Py, Pz Position P P position Q charge quantity R twist S1-S8 process steps t time t1, t2 time T Target position Th threshold ul area ur area Vx, Vy, Vz speed W Way x, y, z direction Z, Z', Z'' state point Z1, Z1', Z1'' value Z2, Z2', Z2'' value QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] US 7 675 300 B2

[0085]

Claims

[1] Computer-implemented method for processing a sample (102) with a nanomanipulator (104) having a measuring tip (106) for processing the sample (102) and a positioning unit (110) for moving the measuring tip (106), comprising the steps: a) providing (S1) permissible value ranges for two or more parameters (A1, A2) of the nanomanipulator (104) and / or the sample (102), wherein the two or more parameters (A1, A2) span a multidimensional parameter space (164), b) determining (S2) a permitted range (166) in the multidimensional parameter space (164) based on the provided permitted value ranges for the two or more parameters (A1, A2), c) receiving (S4) current values ​​(Z1, Z2) and / or determining future values ​​(Z1', Z2') of the two or more parameters (A1, A2), d) determining (S5) whether a state point (Z, Z') corresponding to the current and / or future values ​​(Z1, Z2, Z1', Z2') of the two or more parameters (A1, A2) in the multidimensional parameter space (164) lies outside the permitted range (166), and e) controlling (S8) the positioning unit (110) to stop a movement of the measuring tip (106) and / or to retract the measuring tip (106) with respect to the sample (102) when it is determined that the state point (Z, Z') lies outside the permitted range (166). [2] The method of claim 1, wherein the future values ​​(Z1', Z2') of the two or more parameters (A1, A2) are predicted based on a received user input (G) and / or based on a determined drift movement (172) of the measuring tip (106) relative to the sample (202). [3] Method according to claim 1 or 2, comprising: Determining (S3) a warning range (170) in the multidimensional parameter space (164) for the two or more parameters (A1, A2), Determining (S6) whether the current and / or future state point (Z, Z') in the multidimensional parameter space (164) lies within the determined warning range (170), and Controlling (S7) the positioning unit (110) so that a movement of the measuring tip (106) is slowed down and / or controlling a human-machine interface (138) to output a warning if it is determined that the current and / or future state point (Z, Z') lies within the determined warning range (170). [4] Method according to one of claims 1 to 3, wherein the permitted area (166, 166''), the warning area (170, 170'') and / or a forbidden area (168, 168'') of the multi-dimensional parameter space (164) have discrete boundaries (G1, G2) or continuously merge into one another. [5] Method according to one of claims 1 to 4, wherein the nanomanipulator (104) has a boom (108) which is movably attached to the positioning unit (110) at its base end (112), the measuring tip (106) is arranged at a free end (114) of the boom (108), and the two or more parameters (A1, A2) of the nanomanipulator (104) and / or the sample (102) comprise: a position (Px, Py, Pz) of the foot end (112) of the boom (108) relative to the positioning unit (110), a speed (Vx, Vy, Vz) of the foot end (112) of the boom (108) relative to the positioning unit (110), a deflection (D) of the free end (114) of the cantilever (108) in a z-direction which is arranged perpendicular to the sample (102), a rotation (R) of the free end (114) of the boom (108) about an x-direction which is arranged perpendicular to the z-direction, a bending (B) of the measuring tip (106) relative to the boom (108), and / or Position data (A3-A5) of structures (148) of the sample (102). [6] A method according to any one of claims 1 to 5, further comprising: Receiving images (146) of at least a portion of the sample (102) taken with a scanning electron microscope (124), wherein the two or more parameters (A1, A2) of the nanomanipulator (104) and / or the sample (102) comprise a quantity of charge (Q) on a surface (134) of the sample (102). [7] Method according to one of claims 1 to 6, wherein providing the permitted value ranges for the two or more parameters (A1, A2) comprises providing and / or determining position data (A3-A5) of structures (148) of the sample (102). [8] The method according to claim 7, wherein determining the position data (A3-A5) of the structures (348) of the sample (302) comprises: Receiving one or more images (346) of at least a portion of the sample (302), and Determining the position data (A3-A5) of the structures (348) of the sample (302) by means of image analysis of the one or more received images (346) and / or by means of edge detection of edges (K) of the structures (348) in the one or more received images (356). [9] Method according to claim 7 or 8, wherein determining the position data (A3-A5) of the structures of the sample (402) comprises: Receiving an image (446) of at least a portion of the sample (402), wherein the image (446) captures a defect-free region (174) with a first portion (178) of the structures (448) and a defect-affected region (176) with at least one defect (428) and a second portion (180) of the structures (448), and wherein a geometric shape (182) of the first portion (178) of the structures (448) corresponds to a geometric shape (184) of the second portion (180) of the structures (448), Determining the geometric shape (182) of the first section (178) of the structures (448) in the defect-free area (174) by means of image analysis, and Determining the position data of the second section (180) of the structures (448) in the defect-affected region (176) based on the determined geometric shape (182) of the first section (178) of the structures (448) in the defect-free region (174). [10] Method according to one of claims 1 to 9, comprising: Receiving an image (146) of at least a portion of the sample (102), Controlling a display device (140) for displaying the image (146), Receiving a target position (T) of the measuring tip (106) in the image (146) entered by a user by means of a graphic user interface (144), and fully automatic control of the positioning unit (110) to move the measuring tip (106) to the target position (T). [11] Method according to one of claims 1 to 10, comprising: Determining whether a time period (Δt) since receiving a last user input (G) is greater than a threshold value (Th), and fully automatic control of the positioning unit (110) to move the measuring tip (106) into the determined permissible range (166) of the multidimensional parameter space (164) if the time period (Δt) since receiving the last user input (G) is greater than the threshold value (Th). [12] Method according to one of claims 1 to 11, comprising: Receiving a plurality of images (246) of at least a portion of the sample (202), wherein a structure (248) and / or marking of the sample (202) and the measuring tip (106) are captured in the images (246), and Determining a drift movement (172) of the measuring tip (106) relative to the structure (248) and / or the marking of the sample (202) by image analysis of the received images (246), and / or Determining a drift correction based on the determined drift movement (172) and / or predetermined model data, and fully automatic control of the positioning unit (110) to move the measuring tip (106) according to the determined drift correction. [13] Method according to one of claims 1 to 12, comprising: Controlling an image recording device (124) for recording a first image (546) of a defective section (186) of the sample (502), in which first structures (188) of the sample (502) and one or more defects (528) of the sample (502) are detected, Controlling the image recording device (124) to record a second image (546') of a defect-free section (190) of the sample (502), in which second structures (192) of the sample (502) are detected, the geometric shape (196) of which corresponds to a geometric shape (194) of the first structures (188) in the first image (546), Determining a difference image (546'') based on a subtraction of the second image (546') from the first image (546), Determining position data (P P ) of the one or more defects (528) detected in the first image (546) based on an image analysis of the difference image (546''), and Controlling the image recording device (124) to record a third image (546''') of a defective portion (196) of the sample (502), in which the one or more defects (528) detected in the first image (546) is / are arranged at a predetermined position (M) in the image (546). [14] Method according to one of claims 1 to 13, wherein the nanomanipulator (104) has a boom (108) which is attached at its first end (112) at a fixed angle (α) to the positioning unit (110) and at the second end (114) of which the measuring tip (106) is arranged, the sample (102, 602) is arranged on a rotatable sample table (120), and the method comprises: Receiving an image (646) of at least a portion of the sample (102, 602), wherein structures (648) of the sample (102, 602) and a defect (628) are captured in the image (646), Determining an access angle (β) for the measuring tip (106) for processing the defect (628) such that an access path (W) with the access angle (β) is free of structures (648) of the sample (102, 602), and Controlling the sample table (120) to rotate the sample table (120) based on the determined access angle (β) such that the fixed angle (α) of the measuring tip (106) corresponds to the access angle (β). [15] 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), and a control device (136) configured to carry out the method according to one of claims 1 to 14.

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