Method and apparatus for extending time period until changing a measuring tip of a scanning probe microscope

Abstract

The invention relates to a method and apparatus for prolonging the time period until a measurement tip of a scanning probe microscope is changed. In particular, the invention relates to a method of hardening a measurement tip (120, 127, 130) in a scanning probe microscope (100), the method comprising the step of treating the measurement tip (120, 127, 130) with a beam (160) of an energy beam source (152), the energy beam source (152) being part of the scanning electron microscope (100).

Description

[0001] This application is a divisional application of Chinese Patent Application No. 201780073494.8, filed on November 23, 2017, entitled "Method and Apparatus for Extending Time Limit Until Changing the Measurement Tip of a Scanning Probe Microscope".

[0002] 1. Priority of claims

[0003] This patent application claims priority to German patent application DE10 2016 223 659.8, filed with the German Patent and Trademark Office on November 29, 2016. The German priority application forms part of this patent application by reference. Technical Field

[0004] This invention relates to a method and apparatus for extending the time period before changing the measurement tip of a scanning probe microscope. Background Technology

[0005] Scanning probe microscopy uses a measuring tip to scan a sample or its surface, thus generating measurement data to produce a representation of the sample surface morphology. Hereinafter, scanning probe microscopy is abbreviated as SPM. There are differences between various types of SPM depending on the type of interaction between the measuring tip and the sample surface. Scanning tunneling microscopy (STM) is commonly used, where a voltage is applied between the sample and the measuring tip, which do not contact each other, and the resulting tunneling current is measured.

[0006] In a microscope known as atomic force microscopy (AFM) or scanning force microscopy (SFM), the measurement probe is deflected by atomic forces on the sample surface, typically by van der Waals attraction and / or repulsion forces of exchange interactions.

[0007] In addition to these conventional SPM types, there are several other instrument types for specific application areas, such as magnetic force microscopes or optical and acoustic near-field scanning microscopes.

[0008] Scanning probe microscopy (SPM) can be used in different operating modes. In contact mode, the measuring tip is placed on the sample surface and scans the sample surface in this state. In this case, the distance of the SPM above the sample can be kept constant, and the deflection of the cantilever or elastic beam carrying the measuring tip is measured and used to image the surface. It is also possible to keep the cantilever deflection constant in a closed control loop and track the distance of the SPM to the profile of the sample surface.

[0009] In the second operating mode of non-contact operation, the measuring tip maintains a specified distance from the sample surface and excites the cantilever to oscillate typically at or near the cantilever's resonant frequency. The measuring tip then scans the sample surface. Because the scanning tip does not contact the sample in this operating mode, its wear is lower than in contact mode. However, a disadvantage of this operating mode is that the measuring tip not only scans the sample surface but also, for example, detects the accumulation of contaminants and / or moisture on the sample surface. The measuring tip may become dirty during the process. In subsequent measurements, the dirty measuring tip detects spurious images of the sample surface.

[0010] In intermittent mode (or tapping mode) TM In the third operating mode, the cantilever also undergoes forced oscillation, but the distance between the SPM and the sample surface is chosen such that the measurement tip reaches the sample surface during a small portion of the oscillation cycle. The profile of the sample surface arises from variations in the frequency, amplitude, or phase of the forced oscillation, caused by the interaction between the measurement tip and the sample surface.

[0011] JP H06-114481 A describes the deposition of carbon-containing nanostructures on a cantilevered measurement probe using an electron beam. Subsequently, the nanostructures are formed using an ion beam, whereby the thickness of the nanostructures is "closed" at a predetermined diameter, and the desired tips of the nanostructures are formed under the influence of the ion beam.

[0012] In the paper “Sharpened electron beam deposited tips for high resolution atomic force microscope lithography and imaging” (Applied Physics Letters, 67(28), December 1995, pp. 3732-3734), authors M. Wendel, H. Lorenz, and JP Kotthaus describe an arrangement of nanotip for fabricating structured photoresist for photolithographic purposes. In the presence of organic molecules, the nanotip is deposited using an electron beam. Subsequently, the nanotip is sharpened by etching away the outer surface of the tip under the influence of oxygen plasma. During this process, the nanotip changes its form from a conical shape to a needle-like structure.

[0013] US 2014 / 0110608 A1 describes a method for bending or curling nanostructures without requiring movement of the nanostructure. For this purpose, the nanostructure is irradiated with ions in a direction perpendicular to its longitudinal axis. Depending on the kinetic energy of the irradiated ions, the nanostructure bends in or opposite to the beam direction.

[0014] DE 198 25 404 A1 describes the deposition of needle-like tips on the substrate of a cantilever of a scanning probe microscope. For the purpose of improving mechanical stability between the needle-like tip and the substrate, the transition region between the needle-like tip and the substrate is enhanced, in particular, by the deposition of a coating film on the needle-like tip and / or the substrate.

[0015] US 2012 / 0 159 678 A1 describes the sharpening of a conductive measurement tip in an ion beam, wherein a potential is applied to the conductive measurement probe, the potential having the same sign as the ion beam.

[0016] In the paper "Investigation of fabrication parameters for the electron-beam-induced deposition of contamination tips used in atomic force microscopy" by K.K. Schiffmann, Nanotechnology, 4 (1993), pp. 163-169, optimized deposition parameters for carbon-based measurement tips on silicon carbide pyramids were examined. The measurement tips were deposited using an electron beam and residual gas in a vacuum chamber.

[0017] Due to interaction with the surface of the sample being inspected, conventional SPM-type measuring tips undergo a wear process and must be replaced after a relatively short service life. In particular, it is necessary to analyze inaccessible, highly delicate structures (such as narrow, deep trenches) in the semiconductor industry. This typically requires the use of fine, long measuring tips, known as "tentacle tips." Measuring tips or tentacle tips can be plastically deformed under the influence of the sample, can be damaged during interaction with the sample and / or through handling, or can even easily break. Weary or deformed measuring tips, or even broken measuring tips, in scanning probe microscopy first reduce the lateral spatial resolution of the measuring instrument and secondly falsify the image of the sample being inspected during the inspection process.

[0018] As explained above, a dirty or contaminated measuring tip will not produce an image close to that of the actual sample being inspected. Therefore, the measuring tip must be cleaned at regular intervals. If cleaning is unsuccessful or impossible, the contaminated measuring tip must be replaced.

[0019] The fabrication of the measuring tip for a scanning probe microscope (SPM) is a difficult and therefore expensive process. Furthermore, replacing the measuring tip of an SPM is a time-consuming and therefore costly process, as the measuring instrument cannot be used to examine the sample when the probe is changed. This is particularly true for SPMs operating under vacuum conditions, since the vacuum must typically be broken to change the probe.

[0020] The present invention thus solves the problem of specific methods and apparatuses that allow for the extension of the time interval between probe replacements in a scanning probe microscope. Summary of the Invention

[0021] According to an exemplary embodiment of the present invention, this problem is solved by the method described below. In one embodiment, a method for providing a measuring tip for a scanning probe microscope includes the steps of: (a) providing at least a first measuring tip and at least a second measuring tip, wherein the first measuring tip and the second measuring tip are arranged on a common measuring tip carrier such that only the first measuring tip interacts with the sample to be examined; and (b) irreversibly processing the first measuring tip such that, after the irreversible processing, only the second measuring tip interacts with the sample to be examined.

[0022] The method according to the invention initially uses a first measuring tip to analyze a sample. During sample scanning, the first measuring tip may become worn or contaminated. Consequently, the first measuring tip can be sharpened and / or cleaned at periodic time intervals, i.e., repaired. The repair process performed on the first measuring tip significantly increases its service life. However, during the scanning process and subsequent repair processes, the length of the first measuring tip gradually shortens due to wear. Therefore, a second measuring tip arranged on the measuring tip carrier can also interact with the sample. If this occurs, the superposition of interaction forces with the sample detected by both measuring tips will lead to incorrect analysis of the sample.

[0023] To prevent this, when implementing the method according to the invention, the previously used, worn, irreparable, contaminated, and / or damaged first measuring tip is modified within the scope of an irreversible processing procedure. This modification is made such that the first measuring tip can no longer interact with the sample during further examination of the sample by a second measuring tip or other measuring tip arranged together on the measuring tip carrier. Irreversible processing of the worn first measuring tip can be performed within a scanning probe microscope. Therefore, worn and / or damaged measuring tips no longer automatically lead to complex replacement of the measuring tip carrier within the scope of the method according to the invention. Of course, the method according to the invention, employing a measuring tip carrier on which multiple measuring tips are arranged, promotes an extended time period until a complex replacement of the measuring tip carrier is required, the extension being at least as much as the number of measuring tips on the measuring tip carrier. Therefore, the downtime of the scanning probe microscope is drastically reduced. This is particularly important for combined instruments (which include a scanning electron microscope in addition to a scanning probe microscope), as probe replacement can block both analytical tools of the combined instrument.

[0024] Because particles are frequently absorbed onto the sample surface, the first measuring tip becomes contaminated when detecting interactions with the sample. Therefore, the first measuring tip must be cleaned at regular intervals. If the cleaning process performed within the SPM fails, as explained above, the first measuring tip can be modified within the scope of an irreversible process so that the irreversible process does not interfere with the analytical process when the sample is examined with the second measuring tip.

[0025] Two or more measuring tips arranged together on a measuring tip carrier may include measuring probes made of a metal (e.g., tungsten) or a semiconductor material (e.g., silicon, silicon dioxide, and / or silicon nitride). However, in one exemplary embodiment, the measuring tips of the measuring tip carrier include long, fine measuring tips based on carbon, referred to as “tentacle tips”.

[0026] In one aspect, irreversible treatment of the first measuring tip is achieved if the second measuring tip also interacts with the sample to be inspected and / or if the first measuring tip has contaminants that cannot be removed by the cleaning process.

[0027] If the length difference between the second and first measuring tips becomes smaller than the structural height of the sample to be measured, the second measuring tip also interacts with the sample. In this case, both measuring tips interact with the sample simultaneously in a specific region. In the case of a locally raised sample surface in the form of a step, the height of the step corresponds to or is greater than the length difference between the two measuring tips, and the two measuring tips image the step as a double-edged structure. If the distance between the two measuring tips is greater than the length and width of a depression in the sample to be measured, the depth of the depression is determined to be too small because the shorter measuring tip has already interacted with the sample surface before the longer measuring tip reaches the bottom of the depression.

[0028] In addition, the method may include one or more of the following steps: (i) sharpening the first measuring tip and / or the second measuring tip; (ii) cleaning the first measuring tip and / or the second measuring tip.

[0029] Degradation of the measuring tip due to wear, plastic deformation, and / or contamination alters the information about the sample provided by the measuring tip. Sharpening or resharpening and / or cleaning the measuring tip can restore its condition to a level largely consistent with its initial state. Images of a sample produced by a repaired measuring tip are indistinguishable from those recorded by a new measuring tip.

[0030] The advantage of the described method is that sharpening and cleaning of the measuring tip can be performed in the SPM without having to remove the measuring tip from the scanning probe microscope.

[0031] The sharpening and / or cleaning steps may be repeated once to ten times, preferably once to eight times, more preferably once to five times, and most preferably once to three times.

[0032] Typically, after this number of repair cycles, the second measuring tip begins to interact with the sample in the same way.

[0033] The advantage of the described method is that the same process as the irreversible treatment of the measuring tip by etching at least a portion of it at the end of its service life can be used to remove traces of use (i.e., wear and / or contamination) from the measuring tip during its service life.

[0034] Irreversible processing, sharpening, and / or cleaning can be achieved within a scanning probe microscope.

[0035] Compared to scanning probe microscopes that use a separate measurement tip, this facilitates a dramatic increase in the time between two replacements of the measurement tip carrier.

[0036] Depending on the configuration, the first measuring tip may have a longer length than the second measuring tip, and / or the first measuring tip may have a smaller diameter than the second measuring tip.

[0037] The first measuring tip has a longer length than the second measuring tip, which ensures that only the first measuring tip interacts with the sample in the initial state. The second measuring tip is implemented with a larger diameter than the first measuring tip, which ensures that even at the end of multiple cleaning and / or sharpening steps of the first measuring tip, the second measuring tip still has a suitable diameter for examining the sample.

[0038] An irreversible process may shorten the length of the first measuring tip, so that only the second measuring tip interacts with the sample to be examined thereafter.

[0039] Therefore, in one exemplary embodiment, the irreversible processing shortens the length of the first measuring tip prior to the irreversible processing to at least the extent that the length of the first measuring tip after the irreversible processing is shortened by the length difference between the first and second measuring tips in their initial state.

[0040] The first and second measuring tips may have an array-shaped embodiment, and / or the free ends of the first and second measuring tips may be pointed.

[0041] The length of the first measuring tip can be 300 nm to 10 µm, preferably 350 nm to 8 µm, more preferably 400 nm to 6 µm, and most preferably 450 nm to 4 µm, and / or the length difference between the first and second measuring probes can be 10 nm to 1000 nm, preferably 20 nm to 800 nm, more preferably 30 nm to 600 nm, and most preferably 40 nm to 500 nm, and / or the length of the second measuring probe can be 100 nm to 5000 nm, preferably 120 nm to 4000 nm, more preferably 140 nm to 3000 nm, and most preferably 150 nm to 2000 nm. Furthermore, the length difference between the first and second measuring probes can be adapted to the maximum height difference of the sample to be examined.

[0042] The diameter of the first measuring tip can range from 5 nm to 50 nm, preferably from 5 nm to 40 nm, more preferably from 5 nm to 30 nm, and most preferably from 5 nm to 20 nm, and / or the diameter of the second column can range from 30 nm to 75 nm, preferably from 30 nm to 65 nm, more preferably from 30 nm to 55 nm, and most preferably from 30 nm to 45 nm, and / or the interval between the first measuring tip and the second measuring tip can be from 10 nm to 1 µm, from 20 nm to 800 nm, more preferably from 30 nm to 600 nm, and most preferably from 40 nm to 400 nm.

[0043] Therefore, the measuring tip can provide reproducible data about the sample to be inspected, and the diameter of the measuring tip should not be greater than one-third of the minimum structural width of the sample to be inspected.

[0044] A scanning probe microscope may include: (a) at least two measuring tips arranged together on a measuring tip carrier such that only a first measuring tip can interact with the sample to be examined in the scanning probe microscope; and (b) a processing device configured to modify the first measuring tip by irreversible processing such that only a second measuring tip can interact with the sample to be examined.

[0045] The processing equipment may include an energy beam source and an imaging device for the energy beam, as well as a storage container for etching gas, a gas supply system, and a gas flow rate control system. The energy beam source may include an electron beam source. Furthermore, the scanning probe microscope may include a plasma source arranged outside the reaction chamber of the scanning probe microscope.

[0046] Scanning probe microscopy can be implemented as a method according to any of the foregoing aspects.

[0047] According to another exemplary embodiment of the present invention, the problem described in the foregoing section is solved by the method described below. In one embodiment, the method for hardening a measurement tip includes the step of treating the measurement tip with a beam from an energy beam source.

[0048] Measurement tips typically include carbon-based tips, which are generated by an energy beam under conditions of a carbon-containing precursor gas. In the absence of a precursor gas, the treatment of the generated measurement tip by energy beam irradiation densifies the material deposited as the measurement tip. Therefore, compared to measurement tips not treated with an energy beam, the material of the measurement tip becomes harder and resists the interaction forces between the measurement tip and the sample for a longer period of time. This significantly extends the time until the measurement tip is replaced.

[0049] Furthermore, due to the contact between the measuring tip and the sample surface, and the plastic deformation of the material at the tip of the measuring tip, the curvature of the tip can be significantly reduced. This substantially reduces the possibility of incorrect interpretation of the images generated by the measuring tip.

[0050] When a measurement tip is processed by an energy beam source, the angle between the beam direction and the longitudinal axis of the measurement tip can include ±10°, preferably ±5°, more preferably ±2° or ±1°. When the measurement tip is hardened by an electron beam, it is advantageous if the direction of the electron beam and the longitudinal axis of the measurement tip to be hardened have a specified angle.

[0051] Preferably, the carbon-based measuring tip (“tentacle tip”) is grown in the direction of the incident energy beam. Therefore, performing the post-processing steps for the hardened measuring tip as described above requires very little additional equipment cost.

[0052] The method may also include the following steps: directly manufacturing the measurement tip using the beam of the energy beam source and the precursor gas before the measurement tip is processed by the beam of the energy beam source.

[0053] By performing the post-processing step directly after the measurement tip is manufactured using the energy beam used for deposition, the adjustment cost of the hardening step of the measurement tip is minimized.

[0054] Beam processing of a measurement tip using an energy beam source can include scanning the beam of the energy beam source across the tip of the measurement tip.

[0055] An energy beam source may include an electron beam source. An energy beam source may be a component of a scanning electron microscope. An energy beam may include an electron beam.

[0056] Because electrons primarily facilitate localized energy deposition in space and secondarily have only minor, undesirable side effects (e.g., in the form of melting from the measurement tip material), an electron beam is preferred. Furthermore, electron beams often require deposition at the measurement tip, and are therefore commonly already present in scanning probe microscopes according to the invention. Additionally, the use of ions, atoms, or molecules for the purpose of hardening the measurement tip is also conceivable.

[0057] The method may also include the step of changing the kinetic energy of the electron beam while processing the measurement tip.

[0058] Changing the kinetic energy of the electron beam when processing the measurement tip can include changing the kinetic energy of the electron beam as the electron beam is scanned at the tip of the measurement tip.

[0059] The selection of the kinetic energy of the electrons in the electron beam can set the location where the electrons deposit most of their energy at the measuring tip.

[0060] The energy range of the electron beam may include 50 eV to 30 keV, preferably 50 eV to 20 keV, more preferably 50 eV to 25 keV, and most preferably 50 eV to 6 keV, and / or the current of the electron beam may include 1 pA to 100 nA, preferably 5 pA to 50 nA, more preferably 20 pA to 20 nA, and most preferably 100 pA to 10 nA, and / or the diameter of the electron beam at the measuring tip may be 1 nm to 100 nm, preferably 1.5 nm to 50 nm, more preferably 2 nm to 30 nm, and most preferably 2.5 nm to 15 nm.

[0061] The duration of the residence time of the electron beam during scanning can include 1 ns to 1 s, preferably 10 ns to 200 ms, more preferably 10 ns to 40 ms, and most preferably 15 ns to 20 ms, and / or the duration of the repetition time during scanning can include 100 ms to 100 s, preferably 300 ms to 70 s, more preferably 1 s to 30 s, and most preferably 2 s to 10 s.

[0062] The area scanned by the electron beam can range from 1000 µm × 1000 µm, preferably 500 µm × 500 µm, more preferably 100 µm × 100 µm, and even more preferably 25 µm × 25 µm.

[0063] A scanning probe microscope may include: (a) a measuring tip having a pointed tip; (b) a measuring head of the scanning probe microscope configured to align the tip of the measuring tip substantially in an antiparallel manner with respect to the direction of the energy beam; and (c) a device configured to direct the energy beam onto the tip of the measuring tip.

[0064] In this application and elsewhere, the expression "substantially" means, when a measured variable is measured using a measuring instrument according to the prior art, that the measured variable is within its error tolerance.

[0065] Scanning probe microscopy can be implemented as a method according to any of the aspects discussed above.

[0066] According to the present invention and other exemplary embodiments, the problems described in the foregoing sections are solved by the methods described below. In one embodiment, a method for cleaning a measurement probe and / or sharpening, thinning and / or cleaning a measurement tip within a scanning probe microscope includes the steps of: (a) generating plasma outside the scanning probe microscope; and (b) equipping the externally generated plasma at the location of the measurement probe within the scanning probe microscope for the purpose of cleaning the measurement probe, and / or equipping the externally generated plasma at the location of the measurement tip within the scanning probe microscope for the purpose of sharpening, thinning and / or cleaning the measurement tip.

[0067] Plasma contains a charged component; typically ions and electrons. Charged particles typically possess high kinetic energy and recombine rapidly. At the point of generation, the low-pressure plasma contains portions of charged particles that can have adverse effects on samples, such as measurement probes or sensitive measurement tips. On the one hand, charged particles cause significant heating of the sample; on the other hand, they can damage or even destroy sensitive samples (such as measurement tips) through the sputtering effect of charged particles from the plasma, particularly ions. In either case, portions of the ions are embedded in the sample, leading to alterations to the sample surface.

[0068] In addition to charged particles, free radicals are also generated during plasma production. Plasma free radicals are primarily lost through a slow deactivation process.

[0069] It may be difficult to control the plasma composition only at the location of plasma generation. External generation of the plasma opens up additional degrees of freedom when setting the composition of the plasma on the exposed measurement probe, measurement tip, or measurement tip carrier. Because the plasma source and the sample to be processed (e.g., the measurement tip) are spatially separated, the ratio of sample heating, physical sputtering by the charged components of the plasma, and chemical etching (preferably induced by plasma radicals) can be set. Therefore, the processing steps of sharpening, thinning, and / or cleaning the measurement tip can be adapted to its composition and configuration. By removing traces of use from the measurement tip in a controlled manner in a scanning probe microscope, the measurement tip can be restored to a level that allows it to supply measurement data as if it were a new, unused measurement tip.

[0070] The configuration of externally generated plasma may include: guiding the externally generated plasma to the measurement tip or measurement probe position of the scanning probe microscope.

[0071] For this purpose, a wired or tubular system connects the output of the plasma source to the reaction chamber of a scanning probe microscope.

[0072] In addition, the method may include the following steps: setting a portion of the charged particles of the externally generated plasma at the location of the measuring probe or measuring tip by means of the difference between the pressure at the location of the measuring probe or measuring tip and the source pressure of the plasma source, the distance between the measuring probe or measuring tip and the plasma source, and / or the cross section of the line system between the plasma source and the scanning probe microscope.

[0073] The spatial distance between the measuring probe or tip and the plasma source, the pressure difference between these locations, and the geometry of the tubular system connecting the plasma source and the scanning probe microscope are important parameters for determining the duration of plasma particle transport from the source to the measuring probe or tip. Therefore, these parameters have a decisive influence on the plasma composition at the location of the measuring probe or tip.

[0074] The source pressure of the plasma source can range from 0.05 Pa to 250 Pa. Before activating the plasma source, the pressure at the location of the measuring probe or measuring tip can range from 1 Pa to 10 Pa. -7 Pa, preferably 0.2 Pa to 10 Pa -6 Pa, more preferably 10 -1 Pa to 10 -5 Pa and most preferably 10 -2 Up to 10 -4 Pa. The distance between the measuring probe or measuring tip and the output of the plasma source can be 1 cm to 10 m, preferably 2 cm to 5 m, more preferably 5 cm to 2 m, and most preferably 10 cm to 1 m. The cross-sectional area of ​​the tube system can be 1 mm². 2 Up to 100 cm 2 Preferably 1 cm 2 Up to 80 cm 2 More preferably 10 cm 2 Up to 60 cm 2 And the most preferred size is 20 cm. 2 Up to 40 cm 2 .

[0075] On the one hand, choosing the smallest possible cross-section of the tube system is advantageous, which thus increases the concentration of free radicals at the measurement tip. On the other hand, a small tube cross-section increases the interaction between free radicals and with the tube wall, and therefore reduces their concentration during transport from the plasma source to the measurement tip. Therefore, a trade-off needs to be found between these two opposing trends in each plasma.

[0076] In one respect, the portion of charged particles in the externally generated plasma is substantially zero at the location of the measuring probe or measuring tip.

[0077] In this scenario, only free radicals still present from the plasma generation process cause etching of the measurement probe or tip. The free radicals from the remaining plasma do not develop into a sputtering effect. Damage to the measurement probe or tip is largely avoided.

[0078] At the location of the measuring probe or measuring tip, the externally generated plasma may include oxygen radicals, hydroxyl radicals, nitric oxide radicals, and / or nitrous oxide radicals. In this application, a radical should be understood as an atom or molecule having at least one unpaired valence electron.

[0079] Externally generated plasma can act on the position of the measuring tip for a duration of 1 second to 100 minutes, preferably 5 seconds to 50 minutes, more preferably 20 seconds to 20 minutes, and most preferably 30 seconds to 10 minutes.

[0080] The measuring tip is typically carbon-based. The sharpening, thinning, and / or cleaning of the measuring tip can be repeated one to ten times, preferably one to eight times, more preferably one to six times, and most preferably two to five times.

[0081] A scanning probe microscope may include: (a) a measurement probe, a measurement tip and / or a measurement tip carrier having at least two measurement tips; (b) a plasma source configured to generate plasma and disposed outside the scanning probe microscope; and (c) a line system configured to guide the plasma generated by the plasma source into the scanning probe microscope.

[0082] In addition, the scanning probe microscope may include a pump system configured to generate a predetermined negative pressure at the location of the measuring probe, the measuring tip, and / or the measuring tip carrier.

[0083] In this application, the term "negative pressure" refers to an absolute pressure specification, which has a value lower than atmospheric pressure under normal conditions.

[0084] In addition, the scanning probe microscope may have a control device that controls the plasma source.

[0085] Scanning probe microscopy can be implemented as a method according to any of the aspects discussed above.

[0086] Finally, a computer program may include instructions that, if executed by a computer system of a scanning probe microscope as described above, cause the scanning probe microscope to perform one of the method steps described above. Attached Figure Description

[0087] Referring to the accompanying drawings, the following detailed description illustrates presently preferred exemplary embodiments of the invention, in which:

[0088] Figure 1 A schematic cross-sectional view of some key components of a scanning probe microscope is shown, including exemplary processing devices for hardening the measurement tip and / or irreversible processing, and / or sharpening, cleaning and / or thinning the measurement tip and / or cleaning the measurement probe;

[0089] Figure 2 The upper part schematically illustrates a probe including a measuring probe, the middle part schematically shows a probe including a measuring tip, and the lower part illustrates a schematic example of a measuring tip carrier having a first measuring tip and four second measuring tips.

[0090] Figure 3 The left-hand image shows an unused measurement tip attached to the measurement probe, and the right-hand image shows the combination of the measurement probe and measurement tip from the left-hand image after the measurement tip has been used to scan the sample.

[0091] Figure 4 The image shows a scanning electron microscope recording of a measuring probe with a measuring tip deposited on it;

[0092] Figure 5 A scanning electron microscope recording of a measurement probe with unused measurement tips deposited on it is shown, wherein the measurement tips are hardened by electron irradiation;

[0093] Figure 6 It shows Figure 5 The combination of the measurement probe and measurement tip after the sample is analyzed by the hardened measurement tip;

[0094] Figure 7 A flowchart of a method for hardening a measurement tip using an energy beam source is reproduced;

[0095] Figure 8 Unused measurement tip is shown in partial image a, worn measurement tip is reproduced in partial image b, contaminated measurement tip is illustrated in partial image c, and measurement tip repaired by electron beam induced etching process is shown in partial image d.

[0096] Figure 9 Unused measurement probes are shown in partial image a, worn measurement probes are reproduced in partial image b, contaminated measurement probes are illustrated in partial image c, and measurement tips repaired by an electron beam-induced etching process are shown in partial image d.

[0097] Figure 10 This demonstrates the cleaning of a scanning probe microscope by externally generated plasma. Figure 9 The measurement tip of part of image c in the image;

[0098] Figure 11 Partial image a shows the sharp part of the unused measuring tip, partial image b reproduces the worn tip of the sharp part, partial image c illustrates the isotropic material melting of the sharp part of partial image b through the etching effect of plasma, and partial image d shows the repaired sharp part of the measuring tip of partial image b, wherein the repair is carried out by the action of plasma that brings about a substantially isotropic etching process.

[0099] Figure 12 The unused measuring tip is shown in partial image a, the worn measuring tip is reproduced in partial image b, the contaminated measuring tip is illustrated in partial image c, and the measuring tip repaired by an electron beam-induced etching process is shown in partial image d.

[0100] Figure 13 The flowchart reproduces a method for cleaning a measurement probe, or sharpening, cleaning and / or thinning a measurement tip using plasma;

[0101] Figure 14 A schematic cross-section is specified through a measuring tip carrier having a first measuring tip and n second measuring tips;

[0102] Figure 15 The diagram shows Figure 14 The measuring tip carrier is used to inspect the sample after its first measuring tip is used.

[0103] Figure 16 It shows Figure 15 The measurement tip carrier is repaired by the action of plasma at its first measurement tip;

[0104] Figure 17 Showing Figure 14 After the measurement tip carrier was modified through use and multiple repairs, the first measurement tip and the second measurement tip interacted with the sample in addition to the first measurement tip.

[0105] Figure 18 It indicates Figure 17 The measurement tip carrier is modified through irreversible processing of the first measurement tip so that only the first second measurement tip still interacts with the sample.

[0106] Figure 19 It shows Figure 14Due to the repeated use and repair process, only the last or nth second measuring tip is prepared for use in the measuring tip carrier; and

[0107] Figure 20 A flowchart is reproduced of a method for providing a measurement tip using a measurement tip carrier based on a scanning probe microscope. Detailed Implementation

[0108] Below, examples using scanning force microscopy or atomic force microscopy (AFM) illustrate in more detail a currently preferred embodiment of the method according to the invention for extending the time interval between two probe changes in a scanning probe microscope. However, the method according to the invention is not limited to the examples discussed below. Alternatively, these can be used with any scanning probe microscope whose force sensor can detect the interaction between the sample and the measuring tip of the scanning probe microscope, thus subjecting the measuring tip to wear, plastic deformation, and / or contamination.

[0109] First, we describe various components of scanning probe microscopes (SPMs) that allow for extended use of the measurement tip. Figure 1 A schematic cross-sectional view of a key component passing through the scanning probe microscope 100 is shown. Figure 1 In the example shown, the scanning probe microscope 100 is a scanning force microscope or an atomic force microscope (AFM). However, the methods described below may also be used, for example, in a scanning tunneling microscope.

[0110] The measuring head 102 is mounted in the scanning probe microscope 100. The measuring head 102 includes a holding device 105. The holding device 105 ( Figure 1 (Not shown in the image) The measuring head 102 is fixed to the frame of the SPM 100. The retaining device 105 can be positioned about a longitudinal axis extending in the horizontal direction (also not shown in the image). Figure 1 (As shown in the diagram) rotates. A piezoelectric actuator 107 is attached to the holding device 105 of the measuring head 102, and the piezoelectric actuator 107 causes its free end to rotate in three spatial directions (not shown in the diagram). Figure 1 (As shown in the figure) moves upward. Attached to the free end of the piezoelectric actuator 107 is a bending rod 110, which is referred to below as a cantilever 110 as is common in the art.

[0111] like Figure 2 As shown schematically enlarged in the upper portion, the cantilever 110 has a retaining plate 112 attached to the piezoelectric actuator 107. The end of the cantilever 110 away from the retaining plate 112 carries a measuring probe 115. The measuring probe 115 may be in the form of a pyramid.

[0112] The cantilever 110 and the measuring probe 115 can be configured in a single integral component. As an example, the cantilever 110 and the measuring probe 115 can be made of a metal such as tungsten, cobalt, iridium, or a metal alloy, or of a semiconductor such as silicon or silicon nitride. Alternatively, the cantilever 110 and the measuring probe 115 can be manufactured as two separate components and then connected to each other. This can be achieved, for example, by adhesive bonding.

[0113] like Figure 2 As shown in the central portion of the image, an elongated measuring tip 120 (hereinafter also referred to as the tentacle tip 120) is additionally deposited on the tip 116 of the measuring probe 117, which may have a different form than the measuring probe 115. Preferably, this is achieved by providing a carbon-containing precursor gas and by directing an electron beam onto the measuring probe 117 along its longitudinal axis 118. The measuring tip 120 then grows in the opposite direction to the electron beam. The deposition of the carbon-based elongated columnar measuring tip 120 is described in detail by the author K.K. Schiffmann in the paper “Investigation of fabrication parameters of the electron-beam-induced deposition of contamination tips used in atomic force microscopy,” which has been cited in the introduction.

[0114] The method for extending the service life of the measuring tip 120 of a scanning probe microscope, explained below, primarily relates to the stinger tip 120. However, as explained below, the described method can also be used for cleaning the routine measuring probe 115. Unlike Figure 2 As shown, the measurement tip 120 does not need to be deposited on the measurement probes 115, 117. Alternatively, the carbon-based measurement tip 120 can be deposited directly on the cantilever 110.

[0115] Instead of a single measuring tip 120, a measuring tip carrier 125 with two or more measuring tips can be attached to the cantilever 110. Figure 2 The lower portion is shown schematically and in a highly magnified manner, through a cross-section of the measuring tip carrier 125 having five measuring tips (first measuring tip 127 and four second measuring tips 130). The measuring tips 127 and 130 can be arranged on the measuring tip carrier 125 in any configuration. Except... Figure 2 The linear configuration shown can also be used, for example, with the measuring tips 127 and 130 arranged in a circular manner. Furthermore, the measuring tips 127 and 130 can be arranged in a two-dimensional field.

[0116] like Figure 2 As shown in the lower part of the image, the measuring tips 127 and 130 can be grown directly onto the measuring tip carrier 125. However, the measuring tips 127 and 130 can also be deposited on what is used as the measuring probe 115. Figure 2 On a measuring probe (not shown), for example on the tip of a pyramid. In addition to measuring tips 127 and 130, one or more measuring probes 115 and 117 may also be attached to measuring tip carrier 125.

[0117] The combination of suspension 110 and measuring probe 115, suspension 110 and measuring tip 120, or suspension 110 and measuring tip carrier 125 is hereinafter referred to as probe 122. When measuring probe 115, measuring tip 120, or measuring tip carrier 125 is changed, the corresponding probe 122 is always replaced.

[0118] refer to Figure 1 The sample 132 to be inspected is attached to the sample stage 135. As an example, this can be achieved by placing the sample 132 on the bearing point of the sample stage 135 in a vacuum or high vacuum environment, or by electrostatic interaction between the sample stage 135 and the conductive back side of the sample 132.

[0119] Sample 132 can be a component or structured part of any microstructure. As an example, sample 132 may include a transmissive or reflective photomask and / or a template for nanoimprint technology. Furthermore, SPM 110 can be used to inspect, for example, integrated circuits, microelectromechanical systems (MEMS), and / or photonic integrated circuits.

[0120] like Figure 1 As indicated by the arrows, the sample stage 135 can be moved in three spatial directions via the positioning system 137 relative to the measuring head 102 of the AFM 100. Figure 1 In the example, the positioning system 137 is implemented as a plurality of micromanipulators. An alternative embodiment of the positioning system 137 may be a piezoelectric actuator. The positioning system 137 is controlled by signals from the control device 185. In an alternative embodiment, the control device 185 does not move the sample stage 135, but instead moves the holding device 105 of the measuring head 102 of the AFM 100. Furthermore, the control device 185 performs coarse positioning of the sample 132 in height (Z direction), and it is possible for the piezoelectric actuator 107 of the measuring head 102 to perform precise height setting of the AFM 100. The control device 185 may be part of the computer system 187 of the scanning probe microscope 100.

[0121] As an alternative or additional example, in other embodiments, the relative movement between the sample 132 and the measuring probe 115 or measuring tip 120 may be divided between the positioning system 137 and the piezoelectric actuator 107. As an example, the positioning system 137 performs movement of the sample 132 in the sample plane (xy plane), and the piezoelectric actuator 107 facilitates movement of the measuring tip 120 or generally the probe 122 in a direction orthogonal to the sample (z direction).

[0122] Figure 1 The exemplary scanning probe microscope 100 includes a modified scanning electron microscope (SEM) 150. An electron gun 152 generates an electron beam 160, which passes through an imaging element (not in the column) arranged in a column 155. Figure 1 (As shown in the diagram) The electron beam 160 is directed as a focused electron beam 160 to the sample 132 at position 162, the sample being arranged on the sample stage 135. Furthermore, the imaging element of the column 155 of the SEM 150 can scan the electron beam 160 on the sample 132.

[0123] Electrons backscattered from electron beam 160 and secondary electrons generated by electron beam 160 are recorded by detector 163. Detector 163, arranged in electron column 155, is referred to as a "lens detector." In various embodiments, detector 163 may be mounted in column 155. Detector 163 is controlled by control device 185. Furthermore, control device 185 of SPM 100 receives measurement data from detector 163. Control device 185 may generate an image from the measurement data and / or data from measuring head 102, which appears on monitor 190.

[0124] As an alternative or additional example, the scanning probe microscope 150 may have a detector 165 for backscattered electrons or secondary electrons, the detector being arranged outside the electron column 155. The detector 165 is also controlled by a control device 185.

[0125] In addition to imaging sample 132, electron beam 160 can also be used to image measurement probe 115 and measurement tips 120, 127, 130. For the purpose of imaging measurement probe 115 or measurement tips 120, 127, 130, sample stage 135 is empty of a sample, allowing measurement probe 115 or measurement tips 120, 127, 130 to be brought to position 162. If necessary, sample stage 135 is additionally lowered in the Z direction. For the purpose of analyzing measurement probe 115 or measurement tips 120, 127, 130, the measuring head 102 of SPM 100 rotates about the longitudinal axis of the holding device 105 of measuring head 102. The rotation can be set to any angle between 0° and 360°. The rotation of measuring head 102 can be controlled by control device 185 of SPM 100.

[0126] In addition to analyzing the measurement tips 120, 127, and 130, the electron beam 160 of the SEM 150 can also be used to harden the measurement tips 120, 127, and 130. Figure 3 The left-hand portion of the image shows a measurement probe 317 with a carbon-based measurement tip 320 grown according to the prior art. The measurement tip 320 is not deposited on the tip 116 of the measurement probe 317. Figure 3 The right-hand portion of the image shows the measuring tip 320 of the measuring probe 317 after scanning the sample 132 with the measuring tip 320. The carbon-based material of the measuring tip 320 is soft and therefore undergoes rapid wear. Figure 3 In the right-hand portion of the image, the length of the measuring tip 320 has been reduced so that both the tips 116 and 320 of the measuring probe 317 can interact simultaneously with the sample 132 to be inspected. Figure 3 Compared to the unused measuring tip 320 in the left-hand portion of the image, the worn measuring tip 320 has a significantly reduced radius of curvature, which increases the minimum possible area in the interaction zone with the sample. Therefore, the spatial resolution of the measuring tip 320 is significantly reduced. Furthermore—as already mentioned—besides the measuring tip 320, there is a risk that the tip 116 of the measuring probe 317 will interact with the sample 132. Therefore, the data generated by scanning may become unusable. Furthermore, there is a risk that the sensitive sample 132 may be damaged by the tip 116 of the measuring probe 317. Moreover, the evaluation of measurement data can become more difficult due to the ambiguous interaction between the measuring probe 317 and the sample 132.

[0127] Figure 4 The electron beam 160 of SEM 150 is used to scan the measurement tip 120 and its surroundings. Square 410 represents a magnified cross-section of the measurement probe 117 and the measurement tip 120. Scanning the measurement tip 120 with the electron beam should densify the soft, carbon-based material of the measurement tips 120, 127, and 130 and thus harden the latter. Figure 4 In the example shown, the scanning area of ​​the electron beam 160, including the measurement tips 120, 127, and 130, is an area of ​​approximately 250 nm × 250 nm. The electrons in the electron beam 160 have a kinetic energy of 5 keV. The electron beam 160 is focused into a spot with a diameter of 1 nm at position 162. Figure 4In the example shown, the residence time and repetition time of the electron beam 160 at one location are 100 µs and 5 ms, respectively. The entire irradiation process of the scanning region 410 takes 5 minutes. The SEM 150 is controlled or adjusted by the control device 185. The values ​​specified here can be modified within a relatively large range without substantially altering the densification of the measurement tips 120, 127, and 130 caused by irradiation. As an example, the material of the measurement tips 120, 127, and 130 can be densified with electron kinetic energies in the range of 20 to 50 keV. The densification process ends when the resulting measurement tips 120, 127, and 130 have the structure of the corresponding lattice. The material of the measurement tips 120, 127, and 130 cannot achieve a high density.

[0128] In the case of a long measuring tip 120, it is advantageous to adapt the focus and / or energy of the electron beam 160 to the local height of the measuring tip 120 during scanning on the measuring tip 120, so as to deliver energy deposition to the desired location within the measuring tips 120, 127, 130.

[0129] Figure 5 Images of the measurement tip 120 after irradiation with an electron beam 160 for the purpose of hardening the measurement tip 120 are shown. Analysis of the electron beam 160 after the irradiation process using SEM 150. Figure 5 The measuring probe 117 and measuring tip 120 are shown.

[0130] Figure 6 The image shows a portion of the measurement tip 120 and measurement probe 117 after a scan is performed in the measurement head 102 of the AFM 100. Figure 5 The processing time of the measuring tip 120 and Figure 3 The processing time of the measuring tip 120 shown is comparable. This can be seen from... Figure 6 It is clear that, Figure 6 The hardened measuring tip 120 is essentially free of wear. There is only a small amount of contaminant 650 at the very tip of the measuring tip. Figure 5 and Figure 6 The comparison thus provides the following evidence: the material of the measuring tip 120 can be dense, and thus hardened by processing the carbon-based measuring tip 120 or the tentacle tip 120, so that the measuring tip 120 post-processed with the electron beam 160 allows for a significantly longer processing time compared to the measuring tip 120 not hardened by the electron beam.

[0131] Electrons radiated onto the measuring tip 120 by the electron beam 160 essentially emit their energy to interact with the electrons of the atoms in the measuring tip 120. In this process, the electrons of the atoms in the measuring tip 120 can be excited, allowing the interatomic bonds between the atoms in the measuring tip 120 to be broken, facilitating subsequent reformation. During bond reformation, typically an energy-advantaged configuration of the atoms in the measuring tip 120 will emerge, which is more densely packed or more stable than the initial configuration. As an example, an energy-advantaged structure of the measuring tip 120 made of carbon has a lattice in the form of a diamond structure.

[0132] Using the tentacle tip 120 Figures 4 to 6 The diagram illustrates the hardening of the measuring tip using electron irradiation. (As shown in...) Figure 3 In comparison, it can be seen from Figure 5 and 6 It has been learned that hardening the tendril tip 120 with an electron beam 160 provides impressive results. However, it is also conceivable to densify and thus harden the conventional measurement probe 115 by means of an electron beam 160. As explained above, the densification process can be carried out as long as the portion of the lattice or conventional measurement probe 115 does not yet have the most densely packed lattice atoms.

[0133] exist Figures 4 to 6 In the example specified, the hardening of the measurement tips 120, 127, and 130 is performed using an electron beam 160. This is advantageous because the SPM 100 includes a SEM 150 for analyzing sample 132. However, ion beams, atomic beams, molecular beams, and / or photon beams can also be used for the purpose of hardening the measurement tips 120, 127, and 130.

[0134] Figure 7 A flowchart 700 illustrates the implementation of the method described above. At 710, the method begins. The first three steps 720, 730, and 740 are optional, therefore their edges are... Figure 7The positions of the measuring tips 120, 127, and 130 are established in step 720. This can be done using an energy beam source (e.g., an electron or ion source) which is then used to scan the beam across the measuring tips for the purpose of hardening them. However, the positions of the measuring tips 120, 127, and 130 can also be established using other measuring instruments. The positions of the measuring tips 120, 127, and 130 can also be retrieved from the memory of the control device 185. Then, in step 730, the tip 123 of the measuring tips 120, 127, and 130 is aligned with the direction of the beam 160 of the energy beam source 152 via the measuring head 102 of the SPM 100 in an antiparallel manner. In step 740, the parameters of the beam of the energy beam source 152 are set. Preferably, this step is performed by the control device 185. In an alternative embodiment, the parameters of the beam 160 of the energy beam source 152 can be set manually. In step 750, the beam 160 of the energy beam source 152 is scanned on the measuring tips 120, 127, 130, and preferably on the area 420 around the measuring tips 120, 127, 130. In step 760, the method ends.

[0135] Refer again Figure 1 In addition to analyzing sample 132, measuring probe 115 and measuring tips 120, 127, 130, and hardening measuring tips 120, 127, 130, the electron beam 160 of SEM 150 can also be used to treat defects in sample 132. To treat sample 132 arranged on sample stage 135, i.e., to repair defects in said sample, scanning probe microscope 100 includes at least two supply containers 167 and 172 for two different processing gases. First supply container 167 stores a first precursor gas, particularly a first carbon-containing precursor gas. As an example, a metal carbonyl group (e.g., chromium hexacarbonyl) or a main group element alkoxide such as TEOS can be stored in first supply container 167. Using the precursor gas stored in first supply container 167, missing material, such as missing absorbing material in a photomask, can be deposited on sample 132.

[0136] The second supply container 172 stores etching gas, which enables an electron beam-induced etching process. Using the electron beam-induced etching process, excess material can be removed from the sample 132. Etching gases may include, for example, xenon difluoride (XeF2), chlorine (Cl2), oxygen (O2), ozone (O3), water vapor (H2O), hydrogen peroxide (H2O2), nitrous oxide (N2O), nitric oxide (NO), nitrogen dioxide (NO2), nitric acid (HNO3), ammonia (NH3), or sulfur hexafluoride (SF6).

[0137] Each of the supply containers 167 and 172 has its own control valves 168 and 173 to monitor or control the amount of corresponding gas supplied per unit time, i.e., the gas volumetric flow rate at position 162 where the electron beam 160 is incident on the sample 132, cantilever 122, or measuring probes 115, 120, 127, 130. Control valves 168 and 173 are controlled and monitored by a control device 185. Using this, the partial pressure conditions of the gas supplied at processing positions 162 or 116 can be set to deposit at measuring tips 120, 127, 130 over a wide range.

[0138] In addition, Figure 1 In the exemplary scanning probe microscope 100, each supply container 167, 172 has its own gas feed line system 169 and 174, which terminates at the sample 132 or measurement probe 115, 120, 127, 130 near the incident point 162 of the electron beam 160 with nozzles 170, 175.

[0139] exist Figure 1 In the example shown, valves 168 and 173 are arranged near the corresponding containers 167 and 172. In an alternative arrangement, control valves 168 and 173 may be integrated near the corresponding nozzles. Figure 1 (Not shown). Different from Figure 1 The illustration shows that, in the absence of a preferred embodiment, one or more gases stored in containers 167 and 172 can also be non-directionally supplied in the lower part of the vacuum chamber 140 or reaction chamber 145 of the SPM 100. In this case, it is advantageous that the scanning probe microscope 100 has an aperture installed between the lower reaction space 145 and the upper portion 147 of the SPM 100. Figure 1 (Not shown in the image), the SPM 100 includes a column 155 of the SEM that provides a focused electron beam 160 in order to prevent excessively low negative pressure in section 147 of the SPM 100.

[0140] Supply containers 167 and 172 may have their own temperature setting and / or control elements, which enable both cooling and heating of the corresponding supply containers 167 and 172. This allows for the storage and, in particular, supply of carbon-containing precursor gases(s) and / or etching gases(s) (not in...) at correspondingly optimal temperatures. Figure 1 (As shown in the diagram) This makes it possible. Furthermore, feed line systems 169 and 174 may include their own temperature setting and / or temperature control elements to provide all process gases (also not shown in the diagram) at their optimal processing temperature at the incident point 162 of the electron beam 160 on the sample 132 or on the measuring probe 115 or measuring tips 120, 127, 130. Figure 1(As shown in the figure). The control device 185 can control the temperature setting elements and temperature control elements of both the supply containers 167, 172 and the gas feed line systems 167, 174.

[0141] It can be operated at room temperature or in a vacuum chamber of 140°C. Figure 1 The scanning probe microscope 100 shown below. Achieving the method explained below requires a negative pressure relative to ambient pressure in the vacuum chamber 140. For this purpose, Figure 1 The SPM 100 includes a pump system 142 that generates and maintains the required negative pressure in the vacuum chamber 140. With control valves 168 and 173 closed, a pressure < 10⁻⁶ is achieved in the vacuum chamber 140 of the SPM 100. -4 The remaining gas pressure is Pa. Pump system 142 may include a separate pump system for the upper portion and lower portion 145 or reaction space 145 of the scanning probe microscope 100 that provides the electron beam 160. Figure 1 (Not shown). Furthermore, the SPM 100 may include a suction extraction device near the processing point 162 of the electron beam 160 to define specified local pressure conditions at the surface of the sample 132 or at the location of the measuring probe 115 or measuring tips 120, 127, 130. Figure 1 (Not shown in the image). The additional suction extraction device is intended to largely prevent one or more volatile reaction products from one or more carbon-containing precursor gases (which are not necessary for the localized deposition of deposits on sample 132 or measuring probes 115, 120, 127, 130) from being deposited on sample 132, the cantilever 110 of probe 122, or measuring probes 115, 120, 127, 130, or in vacuum chamber 140.

[0142] Furthermore, the suction extraction device can prevent particles generated during the etching process from depositing on the cantilever 110 of the sample 132 or probe 122, or distributed in the vacuum chamber 140 of the SPM 100. The functions of the multiple pump systems 142 and the additional suction extraction device can also be controlled and / or monitored by the control device 185.

[0143] Because of the focusable electron beam 160 and the carbon-containing precursor gas that can be stored in the supply container 167, Figure 1The scanning probe microscope 100 is optionally equipped with the option of depositing measurement tips 120, 127, 130 on the cantilever 110, the measurement tip carrier 125, or the substrate of the cantilever 110 or the measurement tip carrier 125. For this purpose, when the sample 132 is not present in the reaction space 145 of the SPM 100 during the deposition of the carbon-based measurement tip 120, the measurement head 102 of the SPM 100 is rotated 180° about the horizontal axis relative to the analysis position of the measurement head 102 and brought to the incident position 162 of the electron beam 160 on the sample 132. In an alternative, currently preferred embodiment, the measurement tips 120, 127, 130 are manufactured in a separate mounting manner away from the SPM 100. The measurement tips 120, 127, 130 are cleaned and / or resharpened in the scanning probe microscope 100.

[0144] In part of image a, Figure 8 A carbon-based measuring tip 120 with a tip 123 is shown. The measuring tip 120 can be deposited directly on the cantilever 110, the measuring probe 117, or the measuring tip carrier 125. The measuring tip 120 has not yet been analyzed for any sample 132. Partial image b shows the measuring tip 120 after it has been used to examine the sample 132. The tip 810 of the measuring tip 820 used has clear signs of use, resulting in visible wear compared to the original tip 122. Partial image c similarly shows the measuring tip 840 used. The tip 835 of the measuring tip 840 is only slightly rounded by interaction with the sample 132 and therefore undergoes very little wear. However, particles 830 have been deposited on the tip 835 of the measuring tip 840. Compared to the new measuring tip 120 in partial image a, the particles 830 alter the measurement data of the measuring tip 850. However, the tips of the used measuring tips 820 and 840 can also be worn tips 810 and contaminated ( Figure 8 (Not shown in the image).

[0145] Using the electron beam 160 of SEM 150 and the etching gas stored in supply container 172, the damage to measurement tips 820 and 840 in partial images b and c can be repaired by a localized electron beam-induced etching process. Partial image d shows the repaired measurement tip 860. The profile of the tip 850 of the repaired measurement tip 860 is substantially the same as the profile of the tip 123 of the new (i.e., unused) measurement tip 120. Therefore, the repaired measurement tip 860 supplies substantially the same measurement data as the new measurement tip 120. The only difference between the two measurement tips 120 and 860 is that the repaired measurement tip 860 is slightly shorter.

[0146] exist Figure 8 The context explains the electron beam-induced etching process for repairing the carbon-based measurement tip 120. Figure 9 It was clarified that the SEM 150 of SPM 100 can also be used to repair the conventional measurement probe 115. Figure 9 Partial image a schematically and very magnified shows a cross section passing through the measuring probe 115 and its tip 116. Figure 9 Partial image b shows the used measurement probe 920, whose tip 910 has been worn due to interaction with sample 132. The resolution of the used measurement probe 920 is worse than that of measurement probe 115. Partial image c shows the used measurement tip 940. Its tip 935 shows only minor signs of use. However, particles 930 are deposited on tip 935, which cause degradation of the image data supplied by measurement probe 940.

[0147] Figure 9 Partial image d shows the repaired measurement probe 960. The profile of the tip 950 of the repaired measurement probe 960 was fabricated using the electron beam 160 of SEM 150 and the etching gas stored in supply container 172, substantially corresponding to the profile of the tip 116 of the new measurement probe 120. The only difference between the two measurement probes 115 and 960 is a slight reduction in the length of the repaired measurement probe 960.

[0148] Refer again Figure 1 The scanning probe microscope 100 includes a plasma source 180, which is connected to the reaction chamber 145 of the SPM 100 via a wire system 182 and a tube system 182 flange. Figure 1An exemplary plasma source 180 generates plasma by induced excitation. Many technological possibilities exist for generating plasma, such as excitation by DC voltage, excitation by capacitance, or radiation by microwaves or lasers. The type of plasma excitation is not important for subsequent excitation. Plasma can be described as a gaseous state in which charged particles (i.e., ions and electrons), excited particles (i.e., free radicals), and often atoms and molecules exist in close proximity to each other in their ground state. The interaction between plasma particles and the surface of a solid sample produces three fundamental effects: (I) heating the sample by irradiation with the rapid electrons of the plasma; (II) the sputtering effect of the high-energy ions of the plasma on the sample surface; and (III) the free radical etching of the sample surface by the plasma (see JT Grant, SD Walck, FJ Scheltens, and AA Voevodin, “Surface science aspects of contamination in TEM sample preparation,” Sample Preparation in Transmission Electron Microscopy of Materials, 4th Edition, edited by RM Anderson and SD Walck, Mater. Res. Soc. Symp. Proc. 480 (1997), pp. 49–71). This combination of plasma particle-sample interactions results in high ablation rates on plasma-exposed samples. However, the action of highly kinetic charged particles can damage or even destroy sensitive samples. Furthermore, the introduction of plasma ions modifies the sample surface to depths of several nanometers.

[0149] Within the plasma or at the walls of the plasma chamber at the plasma source 180°, ions and electrons in the plasma are lost through recombination. This recombination process occurs on a short timescale (within 10^- ... -8 s to 10 -10 Within the range of s). Excited particles (i.e., free radicals) in the plasma return to their ground state by emitting their excitation energy. These deactivation processes occur on longer timescales (within 10 s). -2 s to 10 -4 (within the range of s).

[0150] Plasma is typically used for cleaning surfaces due to its interaction with the sample as described above. Therefore, plasma can be used to clean measurement probe 940 that has been contaminated by use. To avoid the adverse effects of charged particles on measurement probe 940 and, in particular, the sensitive measurement tip 840, the contaminated measurement probe 940 and the contaminated measurement tip 840 are not exposed to plasma during plasma creation. Instead, plasma generated by plasma source 180 is directed into the reaction space 145 of SPM 100 by tube system 182. The composition of the plasma is altered along the path from the output of the plasma source to the location 162 where measurement probe 940 or measurement tip 840 is located.

[0151] The composition of the plasma at position 162 can be set by the following: the output of the plasma source 180 and the distance between position 162, the pressure difference between these two positions, and the diameter of the tube system 182. Figure 1 In the example, the circular tubes of pipe system 182 have a length of 1 cm and a diameter of 0.5 cm. Figure 1 In the example, the distance between the inlet nozzle of reaction chamber 145 and position 162 is approximately 40 cm. Before activating plasma source 180, there is a 10... -2 Pa to 10 -4 Pressure in Pa.

[0152] exist Figure 1 In the example shown, the tube system 182 bridges only the distance between the walls of the plasma source 180 and the reaction chamber 145 of the SPM 100. However, the tube system can also be directed to the vicinity of position 162 to facilitate plasma focusing at the location of the measuring probe 940 or measuring tip 840. Here, the tube system can have a diameter ranging from approximately 1 mm to 2 cm and a length ranging from 10 cm to approximately 100 cm. For a given plasma, optimal values ​​for both parameters should be experimentally established.

[0153] Plasma source 180 uses air to generate plasma. The key excited components of the generated plasma are oxygen (O) radicals, nitric oxide (NO) radicals, nitrous oxide (N₂O) radicals, and OH* radicals. Alternatively, pure oxygen (O₂) can be used to generate plasma. Inert gases such as argon or neon can be added to the gas used to generate plasma. The plasma pressure at the output of plasma source 180 can be set within the range of 0.5 Pa to 250 Pa. The RF power of plasma source 180 can be varied between 10 W and 99 W. Therefore, the intensity of the generated plasma can be modified within a wide range.

[0154] With the geometric parameters specified above, the ions and electrons from the plasma generated by plasma source 180 have essentially disappeared at position 162 due to relaxation. The free radicals of the plasma from plasma source 180 develop an etching effect at position 162 of the measuring probe 940 or measuring tips 820, 840. Therefore, on one hand, the contaminated measuring probe 940 can be cleaned to remove particles 930. Figure 10 The reaction following the free radical action of the plasma generated by plasma source 180 was reproduced. Figure 9 The measurement probe 940. Figure 10 Diagram 1000 shows the result after the measuring probe 940 has been cleaned with plasma for five minutes. Figure 9 The measurement probe 940. The cleaning effect of the plasma has completely removed particle 930 from the tip 935 of the measurement probe 940. The profile of the cleaned measurement tip 1060 remains substantially unchanged due to the etching effect of the plasma. The cleaning process is particularly suitable for particles that are attacked by free radicals more strongly than the measurement tips 120, 127, 130 themselves. Furthermore, it is advantageous if free radicals can generate volatile products from the material of one or more particles. As an example, this applies to carbon-based particles. In contrast, silicon- or chromium-based measurement tips 120, 127, 130 are hardly attacked by free radicals from the plasma source. The plasma source 180 is operated using RF power in the range of 20 W to 50 W. The source pressure of the plasma is 10 Pa.

[0155] Compared to the effects on measurement probes 115 and 117 containing semiconductor or metallic materials, the etching effect of free radicals from the plasma generated by plasma source 180 has different effects on carbon-based measurement tips 120, 127, and 130. Figure 11 Partial image a schematically shows the unused measuring tip 120 or the sharp part 1110 of measuring tips 127, 130. The sharp part 1110 has a tip 123. Partial image b shows the tip 1120 of the sharp part 1110 emerging from tip 123 due to the use of measuring tips 120, 127, 130. The interaction between sample 132 and measuring tip 120 has significantly worn down the latter's tip 1120. The free radicals of the plasma isotropically ablate the material of the carbon-based sharp part 1110 from measuring tip 120. This means that the plasma generated by the plasma source uniformly etches the sharp part 1110 of measuring tip 120. The wear at tip 1120 is eliminated because the isotropic material is ablated by the plasma. Figure 11As shown in partial image d, the tip 1150 of the repaired sharp part 1160 is substantially the same as the unused tip 123. However, the repaired sharp part 1160 is shorter than the original sharp part 1110 from which the tip 120 was measured. At 50 watts of RF power and a source pressure of 10 Pa, a material melting rate of 0.2 nm / min was observed for the geometry described above.

[0156] Figure 12 Repeated in partial images a, b, and c Figure 8 Partial images a, b, and c. Specifically, partial image a again shows a new measuring tip 120, 127, or 130 with a sharp component 1110 and a tip 123. Partial image b shows a tip 810 using a worn measuring tip 820, and partial image c shows a measuring tip 840 with a tip 835 having a grain 830. Figure 12 Partial image d shows the etching effect of free radicals from the plasma generated by plasma source 180 repairing measurement tips 820 and 840. Particles removed from tip 835 by plasma action are extracted from reaction chamber 145 by a suction extraction system of SPM 100 positioned near location 162. In an alternative embodiment, the extraction suction system additionally attached to reaction chamber 145 is deactivated during operation of plasma source 180 to minimize plasma loss at location 162.

[0157] The repaired measuring tip 1260 has a tip 1250 that is essentially in the form of tip 123. Depending on the form of the measuring tips 120, 127, and 130, the explained process can be repeated multiple times. Therefore, the measuring tips 820 and 840 in use can be repaired by the action of plasma, thereby significantly increasing the service life of the carbon-based tentacle tips 120, 127, and 130.

[0158] Compared to the new measurement tip 120, the repaired measurement tip 1260 differs in two ways: first, the repaired measurement tip 1260 is shorter than the new measurement tip 120; second, due to the isotropic etching effect of the plasma, the repaired measurement tip 1260 is thinner than the original measurement tip 120. This means that, in addition to removing usage traces on the measurement tips 820 and 840, plasma can also be used to target the thinning or tapering of the new measurement tip 120. Therefore, measurement tips 120, 127, and 130 can be customized in situ for certain applications, such as scanning trenches with a high aspect ratio.

[0159] Figure 13The flowchart 1300 of the method is reproduced, which can be used to clean the measuring probe 115 or sharpen, clean, and / or thin the measuring tips 120, 127, 130 within a scanning probe microscope 100. At 1310, the method begins. In the first step 1320, plasma is generated outside the scanning probe microscope 100. Then, in the second step 1330, for the purpose of cleaning the measuring probe 115, the externally generated plasma is applied to position 162 of the measuring probe 115 within the scanning probe microscope 100, or for the purpose of sharpening, cleaning, and / or thinning the measuring tips 120, 127, 130, at position 162. Finally, in step 1340, the method ends.

[0160] Figure 14 Figure 1400 schematically illustrates a cross-section through a measurement tip carrier 1410 having (n+1) measurement tips. The measurement tip carrier 1410 may comprise, for example, a semiconductor material from silicon (Si), a compound semiconductor such as silicon nitride (Si3N4) or gallium arsenide (GaAs), a metal such as titanium, or a metal alloy. For stability considerations, the thickness of the measurement tip carrier 1410 is chosen to be as thin as possible to maintain a low mass to be moved by the cantilever 110, typically in the submicron range.

[0161] The measurement tip carrier 1410 includes a first measurement tip 127 and n second measurement tips 130-1 to 130-n. The first measurement tip 127 has a length of (n+1) Δl. Here, n+1 represents the number of measurement tips 127 and 130 on the measurement tip carrier 1410. Δl represents the length difference between adjacent measurement tips 127 and 130 on the measurement tip carrier. The length difference Δl is at least as large as the desired structural depth of the sample to be examined. As an example, for Δl = 80 nm, the second measurement tip 130-1 is approximately 200 nm shorter than the first measurement tip 127, and its diameter is increased by Δl compared to the diameter of the first measurement tip 127. The other second measuring tips 130-2 to 130-n are manufactured such that, firstly, their lengths are each shortened by a fixed amount (e.g., by 200 nm), and secondly, their diameters are increased by a predetermined value (such as Δl) compared to the next longer second measuring tip 130-(n-1).

[0162] As long as the lateral distance between adjacent measuring tips 127, 130 is observed, the measuring tips 127, 130 can be arranged on the measuring tip carrier 1410 in any configuration. As an example, the measuring tips 127, 130 can be deposited on the measuring tip carrier 1410 in a square configuration.

[0163] Due to this definition, n has a minimum value of one. This minimum value is given by the size of the measurement tip carrier 1410 fixed to the cantilever 110 and the distance between the individual measurement tips 127 and 130. The size of the measurement tip carrier can be in a region of 1 µm × 1 µm. The measurement tips 127 and 130 can be deposited with a lateral spacing of approximately 300 nm. Thus, the maximum number of measurement tips 127 and 130 that can be carried by the measurement tip carrier 1410 is in the double-digit range. Therefore, for example, 4 × 4 measurement tips can be arranged in an example of a measurement tip carrier 1410 with a size of 1 µm × 1 µm. As an example, a measurement probe, for example in the form of a truncated measurement probe, can be used as a measurement tip carrier on which an arrangement or array of measurement tips can be grown.

[0164] like Figures 4 to 6 In the context of the individual measuring tip 120, it is also conceivable that the measuring tips 127 and 130 of the measuring tip carrier 1410 are irradiated with an electron beam, and thus the measuring tips are hardened, before being first applied to the analytical sample 132. This increases the lifespan of the first measuring tip 127 and the second measuring tip 130.

[0165] Figure 15 Diagram 1500 shows the first measuring tip 1527 of the measuring probe carrier 1410 after the first measuring tip is used to examine the sample 132. Figure 8 and 12 Similar to what is discussed in the context above, the first measuring tip 1527 exhibits wear on its tip 1510 due to interaction with the sample 132. Alternatively, the original measuring tip 123, the first measuring tip 127, may have been contaminated due to the analysis of the sample 132. Figure 15 (Not shown in the image). In addition to wear on tip 1510, the first measuring tip 1527 may also be additionally contaminated (…). Figure 15 (Not shown in the image).

[0166] As already regarding Figure 12 As explained in the discussion, the wear marks on the first measuring tip 1527, in the form of worn measuring tip 1510 and / or contaminated measuring tip 1527, can be repaired by means of plasma generated by plasma source 180. Figure 16 Diagram 1600 shows the measuring tip carrier 1410 after the action of plasma. The repaired first measuring tip 1627 has a tip 1623 that is substantially indistinguishable from the tip of the new first measuring tip 123. As similarly... Figure 12As explained in the context, the repaired first measuring tip 1627 is shorter and thinner than the new first measuring tip 120. Furthermore, the isotropic etching effect of the plasma generated by the plasma source 180 also results in slightly shortened and thinned second measuring tips 1630-1 to 1630-n.

[0167] If the first measuring tip 1527 is worn and / or contaminated, an electron beam-induced etching process (based on) is used. Figure 8 To describe this as a replacement for the plasma etching process, repair can avoid thinning of the first measuring tip 127 and the second measuring tip. This avoids the second, shorter measuring tip 130 having to be made thicker than the first measuring tip 127. Figure 16 (Not shown).

[0168] The described repair process for the first measuring tip 123 may be repeated multiple times, as the length of the first measuring tip 123 is further shortened in each repair step. After several repetitions, Figure 16 The configuration shown occurs where the first measuring tip 1727, after multiple repairs, has a length comparable to that of the first second measuring probe 1730-1. Therefore, the tips 1723-1 of the first measuring tip 1727 and the first second measuring tip 1730-1 interact with the sample 132. The combined interaction of the measuring tips 1727 and 1730-1 modifies the interaction between the probe 122 (i.e., the probe fixed thereon in a specified manner). Figure 17 The image of sample 132 (shown on monitor 190) generated by the cantilever 110 of the measuring tip carrier 1410 is shown. As explained above, each elevation of sample 132 to be measured is imaged twice, the height of sample 132 exceeding the length difference between the longest and second longest measuring tips, and the width of sample 132 corresponding at least to the lateral spacing between the longest and second longest measuring tips, and the height difference corresponding to the length difference between the two measuring tips. Therefore, a double image always appears with the same distance. When a depression with a depth exceeding the length difference between the longest and second longest measuring tips is imaged, the second longest measuring tip will contact the sample surface before the longest measuring tip has reached the bottom of the depression. The double image and the abrupt change in the depth of the measured profile are therefore important indicators of conflict between measuring tips imaged at the same time.

[0169] if Figure 17If the situation described above occurs, the measuring tip carrier 1410 is again exposed to the effects of plasma originating from plasma source 180. The duration of the effect is chosen such that the plasma (more specifically, plasma radicals) etches (i.e., irreversibly processes) the repaired first measuring tip 1727 to a degree that the remaining first measuring tip 1827 is shorter than the first second measuring tip 1830-1. This context is... Figure 18 As shown in the figure. The remaining first measuring tip 1827 is shorter than the first second measuring tip by at least the following length difference: the length difference between the original first measuring tip 127 and the original first second measuring tip 130-1.

[0170] Instead of plasma, the first measuring tip 1727, which has been repaired multiple times, can be etched using an electron beam-induced etching process. Figure 18 (not shown in the image) is used for etching, i.e., irreversible processing.

[0171] Instead of the previously used first measuring tips 127 and 1627, a first second measuring tip 130-1 (during electron beam induced etching) or a first second measuring tip 1830-1 (during plasma etching) is now used to inspect sample 132. Thus... Figures 15 to 17 The process described in the context is carried out using the first or second measuring tip 130-1 or 1830-1 until the end of its service life.

[0172] At the end of the service life of the first second measuring tip 130-1 or 1830-1, the inspection process of sample 132 is continued with the second second measuring tip 130-2. Figure 19 Diagram 1900 shows the measurement tip carrier 1410 at the end of the service life of the (n-1)th second measurement tip 1930-(n-1). The first measurement tip 127 and the first to (n-2)th second measurement tips 130-1 to 130-(n-2) have been substantially completely removed from the measurement tip carrier 1410 by repeated isotropic plasma etching processes. In the final step, the nth second measurement tip 130-n or 1930-n is used to analyze sample 132.

[0173] Because of the use of the measurement tip carrier 1410 with a measuring tip, the time between two replacements of probe 122 can be extended many times compared to probe 122 with a single measuring probe 115 or measuring probe 120. The service life of the measurement tip carrier 1410 can be significantly increased again by repeatedly repairing or restoring worn and / or contaminated measuring tips 1510. Additionally, the service life of individual measuring tips 127 and 130 of the measurement tip carrier 1410 can be significantly increased again by hardening the individual measuring tips 127 and 130 before their first use.

[0174] final, Figure 20 A flowchart 2000 reproducing the method of providing measuring tips 127, 130 of a scanning probe microscope 100 is shown. At 2010, the method begins. In a first step 2015, at least one first measuring tip 127 and at least one second measuring tip 130 are provided, the measuring tips being arranged on a common measuring tip carrier 1410 such that only the first measuring tip 127 interacts with the sample 132 to be examined. As an example, this can be achieved by the corresponding length difference between the first measuring tip 127 and the second measuring tip 130.

[0175] The method, as indicated by the dashed edge, includes the following optional steps. In step 2020, the first measuring tip 127 and the second measuring tip 130 can be densified and thus hardened by irradiation with an energy beam (such as electron beam 160). Consequently, the lifespan of the first measuring tip 127 and the second measuring tip 130 is increased.

[0176] In step 2025, the index for counting the measuring tips 127 and 130 of the measuring tip carrier 1410 is set to one. In the next step 2030, the sample 132 is inspected by the first measuring tip 127 (more generally, by the i-th measuring tip 130-(i-1)). After a predetermined inspection period, a check is performed in decision block 2035 to determine whether only the first measuring tip 127 (more generally, the i-th measuring tip 130-(i-1)) interacts with the sample 132, or whether a second measuring tip 130 (more generally, the (i+1)-th measuring tip 130-i) also interacts with the sample 132. If only the first measuring tip 127 forms a force sensor for the sample 132, then in step 2040, the required first measuring tip 127 (or the i-th measuring tip) is cleaned and / or its tip is sharpened such that the restored first measuring tip 1627 substantially retains the profile of the original first measuring tip 127. The method then jumps to block 2030 and performs analysis of sample 132 using the repaired first measuring tip 1627.

[0177] If, in decision block 2035, it is noted that the second measuring tip 130 (more generally, the (i+1)th measuring tip 130-i) interacts with the sample 132, then in step 2045, the first measuring tip 127 is irreversibly processed such that, after the irreversible processing, only the second (more generally, the (i+1)th) measuring tip interacts with the sample 132. As an example, the irreversible processing of the first (more generally, the i-th) measuring tip 127 can be performed via a localized electron beam-induced etching process or an isotropic plasma-induced etching process.

[0178] However, in decision block 2050, it is determined whether the index i+1 has reached the final value N. If so, in step 2060, the investigation of sample 132 continues with the last Nth measuring tip. If the last measuring tip 130-n is no longer repairable, the method ends at step 2065. If the decision block's question answers no, then in step 2055, the index i is incremented by one, and in step 2030, the examination of sample 132 continues with the second (more generally, the (i+1)th) measuring tip 130-i.

[0179] The steps of the method described in this application can be implemented by hardware, firmware, software, or a combination thereof.

Claims

1. A method for cleaning a measurement probe (115) and / or sharpening, thinning, and / or cleaning the measurement tip (120, 127, 130) within a scanning probe microscope (100), comprising the following steps: a. Generate plasma outside the scanning probe microscope (100); b. For the purpose of cleaning the measuring probe (115), the externally generated plasma is applied to the position (162) of the measuring probe (115) within the scanning probe microscope (100), and / or for the purpose of sharpening, thinning, and / or cleaning the measuring tips (120, 127, 130), the externally generated plasma is applied to the position (162) of the measuring tips (120, 127, 130) within the scanning probe microscope (100); and c. The composition of charged particles of the externally generated plasma at the location (162) of the measuring probe (115) or the measuring tip (120, 127, 130) by means of the difference between the pressure at the position (162) of the measuring probe (115) or the measuring tip (120, 127, 130) and the source pressure of the plasma source (180), the distance between the measuring probe (115) or the measuring tip (120, 127, 130) and the plasma source (180), and / or the cross-section of the tube system (182) between the plasma source (180) and the scanning probe microscope (100).

2. The method of claim 1, wherein the configuration of the externally generated plasma comprises: The externally generated plasma is directed to the position (162) of the measurement tip (120, 127, 130) or measurement probe (115) of the scanning probe microscope (100).

3. The method according to claim 1 or 2, wherein the portion of charged particles of the externally generated plasma is substantially zero at position (162) of the measuring probe (115) or the measuring tip (120, 127, 130).

4. The method according to claim 1 or 2, wherein the externally generated plasma at the location (162) of the measuring probe (115) or the measuring tip (120, 127, 130) comprises oxygen radicals, hydroxyl radicals, nitric oxide radicals and nitrous oxide radicals.

5. The method according to claim 1 or 2, wherein the externally generated plasma acts on the measuring probe (115) at the location (162) for a duration of 1 second to 100 minutes.

6. The method of claim 5, wherein the duration is from 5 seconds to 50 minutes.

7. The method of claim 5, wherein the duration is from 20 seconds to 20 minutes.

8. The method of claim 5, wherein the duration is from 30 seconds to 10 minutes.

9. The method according to claim 1 or 2, wherein the source pressure of the plasma source (180) ranges from 0.05 Pa to 250 Pa.

10. The method according to claim 1 or 2, wherein the pressure at position (162) of the measuring probe (115) or measuring tip (120, 127, 130) before activating the plasma source (180) ranges from 1 Pa to 10 Pa. -7 Pa.

11. The method of claim 10, wherein the pressure ranges from 0.2 Pa to 10 Pa. -6 Pa.

12. The method of claim 10, wherein the pressure ranges from 10. -1 Pa to 10 -5 Pa.

13. The method of claim 10, wherein the pressure ranges from 10. -2 Up to 10 -4 Pa.

14. The method according to claim 1 or 2, wherein the distance between the measuring probe (115) or the measuring tip (120, 127, 130) and the output of the plasma source (180) can be from 1 cm to 10 m.

15. The method of claim 14, wherein the distance can be from 2 cm to 5 m.

16. The method of claim 14, wherein the distance can be from 5 cm to 2 m.

17. The method of claim 14, wherein the distance can be from 10 cm to 1 m.

18. The method according to claim 1 or 2, wherein the cross-sectional area of ​​the pipe system (182) is 1 mm². 2 Up to 100 cm 2 .

19. The method of claim 18, wherein the area is 1 cm². 2 Up to 80 cm 2 .

20. The method of claim 18, wherein the area is 10 cm². 2 Up to 60 cm 2 .

21. The method of claim 18, wherein the area is 20 cm². 2 Up to 40 cm 2 .

22. The method according to claim 1 or 2, further comprising: The sharpening, thinning, and / or cleaning of the measuring tips (120, 127, 130) were repeated one to ten times.

23. The method of claim 22, further comprising: The sharpening, thinning, and / or cleaning of the measuring tips (120, 127, 130) were repeated one to eight times.

24. The method of claim 22, further comprising: The sharpening, thinning, and / or cleaning of the measuring tips (120, 127, 130) were repeated one to six times.

25. The method of claim 22, further comprising: The sharpening, thinning, and / or cleaning of the measuring tips (120, 127, 130) were repeated two to five times.

26. A scanning probe microscope (100), comprising: a. A measurement probe (115), a measurement tip (120, 127, 130) and / or a measurement tip carrier (125, 1410) having at least two measurement tips (127, 130). b. A plasma source (180), configured to generate plasma and disposed outside the scanning probe microscope (100); and c. A pipe system (182), configured to guide plasma generated by the plasma source (180) into the scanning probe microscope (100), and The composition of charged particles of the plasma generated at the location (162) of the measuring probe (115) or the measuring tip (120, 127, 130) is determined by the difference between the pressure at the position (162) of the measuring probe (115) or the measuring tip (120, 127, 130) and the source pressure of the plasma source (180), the distance between the measuring probe (115) or the measuring tip (120, 127, 130) and the plasma source (180), and / or the cross-section of the tube system (182) between the plasma source (180) and the scanning probe microscope (100).

27. The scanning probe microscope (100) according to claim 26 further comprises a pump system (142) configured to generate a predetermined negative pressure at a position (162) of the measuring probe (115), the measuring tip (120, 127, 130) or the measuring tip carrier (125, 1410).

28. The scanning probe microscope (100) according to claim 26 or 27 further includes a control device (185) configured to control the plasma source (180).

29. The scanning probe microscope (100) according to claim 26 or 27, wherein the measuring tip (120, 127, 130) is carbon-based.

30. The scanning probe microscope (100) according to claim 26 or 27 further includes an energy beam source (152) and an imaging device for an energy beam (160) of said energy beam source (152).

31. The scanning probe microscope (100) according to claim 30, wherein the measuring head (102) is configured such that the measuring probe (115), the measuring tip (120) and / or the measuring tip carrier (125, 1410) having at least two measuring tips (127, 130) are aligned with the direction of the energy beam (160) of the energy beam source (152) in an antiparallel manner.

32. The scanning probe microscope (100) according to claim 26 or 27 further includes at least one storage container (167, 172) for etching gas, a gas supply system (169, 174) and a gas flow rate control system (168, 173).

33. The scanning probe microscope (100) according to claim 26 or 27, wherein the scanning probe microscope (100) is implemented as described in claim 1 or 2.

34. A computer program product comprising instructions that, when executed by a computer system of a scanning probe microscope (100) according to any one of claims 26 to 33, cause the scanning probe microscope (100) to perform the method according to any one of claims 1 to 25.

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