JP2007278896A - Scanning probe microscope and method for acquiring image reflecting physical property value of specimen - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a scanning probe microscope for acquiring, in a short time, a plurality of images which reflect the physical property values of a sample unaffected by temperature drift. <P>SOLUTION: In first acquiring an image reflecting the physical property values of the sample, a probe 21 is scanned two-dimensionally by an XYZ scanner 12, to acquire three-dimensional information on the specimen S. A probe scanning track is calculated by a calculation part 25, based on the direction of the two-dimensional scanning and on the three-dimensional information. The calculated scanning track is stored in a memory 27, and the probe 21 is scanned along the scanning track by the XYZ scanner 12, to acquire an image reflecting the physical property values of the sample; and in acquiring an image that reflects the physical property values of the specimen thereafter, the probe 21 is scanned by the XYZ scanner 12, along the scanning track stored in the memory 27 to acquire an image reflecting the physical property values of the sample S. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a scanning probe microscope that acquires an image reflecting physical property values of a sample.

  A scanning probe microscope (SPM) is a highly applicable microscope that can detect the force of a physical property value of a sample such as an atomic force, a tunnel current, and a magnetic force with a small probe having a diameter of about several nanometers and image it. And it is a widely familiar device.

  In SPM, as shown in FIG. 5, when an inclination occurs between the scanning trajectory L of the probe 21 and the surface of the sample S, when the probe 21 is scanned two-dimensionally with respect to the sample S, Since the distance between the tip of the probe 21 and the surface of the sample S cannot be kept constant, the SPM measurement may not be performed correctly. For example, detection of magnetic force. In order to detect the magnetic force, it is necessary to detect a small amount of magnetic force emitted from the sample. However, the magnetic force has a polarity or a portion where there is no magnetic force, and the probe 21 is based on information on the change of the probe 21 detecting the magnetic force. An appropriate distance between the tip of the sample and the surface of the sample S cannot be set. Therefore, in order to stably detect the magnetic force, the distance between the surface of the sample S and the tip of the probe 21 is optimized, and the probe S is scanned two-dimensionally while keeping the optimum distance constant. Is desirable. However, if the two-dimensional scanning plane of the sample S and the probe 21 is inclined, the distance between the sample and the probe 21 along the Z axis when the probe 21 is scanned along the X axis and the Y axis. Changes, there are cases where the magnetic force cannot be detected.

In response to this problem, Japanese Patent No. 2837083 obtains the surface shape of the sample by SPM measurement every time when measuring the magnetic force, and based on the information on the surface shape of the sample obtained immediately before, An SPM has been proposed that can stably measure magnetic force by calculating a probe scanning trajectory that keeps the distance between them constant and detecting the magnetic force while scanning the probe along the probe scanning trajectory. In this SPM, when measuring the magnetic force, the surface shape measurement and the magnetic force measurement are alternately performed.
Japanese Patent No. 2837083

  As shown in FIG. 6, a general SPM measurement is performed on the surface of the sample S in a sequence of scanning along the X axis → step in the + Y direction → scanning along the X axis. Cost. In general, in SPM, a plurality of images are often acquired continuously for the same sample. When acquiring images in this way, scanning along the X axis is stepped in the + Y direction. ⇒ Scanning along the X-axis ⇒ Image acquisition by a sequence that repeats steps in the + Y direction and scanning along the X-axis ⇒ Step in the -Y direction ⇒ Scanning along the X-axis ⇒ Image by a sequence that repeats steps in the -Y direction Acquisition is repeated. Since image acquisition by this SPM takes time, the distance between the sample S and the probe 21 changes due to the thermal contraction of the structure existing between the sample S and the probe 21 caused by the temperature change. It is greatly affected by so-called temperature drift.

  In SPM of Japanese Patent No. 2837083, when detecting and imaging a target physical property value, for example, magnetic force, a change in the distance between the sample and the probe due to temperature drift has less influence on the surface shape. Since the surface shape information of the sample is acquired each time the magnetic force is measured, at least twice the normal image acquisition time is required. Also, since the probe wears, the amount of wear increases as the number of scans (scan distance) increases.

  The present invention has been made in consideration of such a situation, and the purpose of the present invention is to provide a scanning probe microscope that acquires a plurality of images reflecting the physical property values of a sample without the influence of temperature drift in a short time. Is to provide.

  According to one aspect of the present invention, there is provided a scanning probe microscope that acquires an image reflecting a physical property value of a sample.

  A scanning probe microscope according to the present invention includes a cantilever having a probe at a free end, scanning means for scanning the probe with respect to the sample, detection means for detecting movement of the probe, and surface shape of the sample. Storage means for storing three-dimensional information and correction data for temperature drift in association with each other, and calculation means for calculating a probe scanning trajectory for measuring the physical property value based on the three-dimensional information and the correction data. When the image reflecting the physical property value of the sample is first acquired, the probe is two-dimensionally scanned by the scanning unit to acquire the three-dimensional information and the correction data, and the acquired three-dimensional information The probe scanning trajectory is calculated by the calculation means based on the correction data, the calculated probe scanning trajectory is stored in the storage means, and is calculated. When the scanning means scans the probe according to the probe scanning trajectory to acquire an image reflecting the physical property value of the sample, and when acquiring an image reflecting the physical property value of the sample thereafter, the storage means The probe is scanned by the scanning unit according to the stored probe scanning trajectory, and an image reflecting the physical property value of the sample is acquired.

  Another scanning probe microscope according to the present invention includes a cantilever having a probe at a free end, scanning means for scanning the probe with respect to the sample, detection means for detecting movement of the probe, and the surface of the sample. A storage means for storing the three-dimensional information of the shape and the correction data for the temperature drift in association with each other, and the physical property value based on the three-dimensional information stored in the storage means and the correction data corresponding thereto. Calculation means for calculating a probe scanning trajectory at the time of measurement, and when the image reflecting the physical property value of the sample is first acquired, the probe is moved along the XY plane with respect to the sample by the scanning means. XY scanning and measuring the distance between the sample and the probe based on the movement of the probe obtained by the detection means, Acquires three-dimensional information of the shape, stores the three-dimensional information together with the three-dimensional information as the correction data in the XY scanning direction when the three-dimensional information is acquired, stores them in the storage unit, and associates them with the storage unit The probe scanning trajectory when the physical property value is measured based on the three-dimensional information stored in the memory and the correction data is calculated by the calculation means, and the calculated probe scanning trajectory is stored in the storage means. Scanning the probe by the scanning unit according to the calculated probe scanning trajectory, and measuring the physical property value of the sample based on the movement of the probe obtained by the detecting unit to reflect an image reflecting the physical property value of the sample The probe scanning trajectory stored in the storage means when acquiring and subsequently acquiring an image reflecting the physical property value of the sample Thus obtaining an image that reflects the physical properties of the sample by measuring the physical properties of the sample based on the movement of the probe obtained by the detection means while scanning the probe by the scanning means.

  According to another aspect of the present invention, there is provided a method for acquiring an image reflecting physical property values of a sample with a scanning probe microscope.

  In the image acquisition method according to the present invention, when the image reflecting the physical property value of the sample is first acquired, the probe is two-dimensionally scanned to acquire the three-dimensional information of the surface shape of the sample, and the three-dimensional information and The probe scanning trajectory is calculated based on the two-dimensional scanning direction and stored, and the probe is scanned according to the probe scanning trajectory to obtain an image reflecting the physical property value of the sample. When acquiring an image reflecting the physical property value thereafter, the probe is scanned according to the stored probe scanning trajectory to acquire an image reflecting the physical property value of the sample.

  In another image acquisition method according to the present invention, when an image reflecting a physical property value of a sample is first acquired, the probe is XY scanned along the XY plane with respect to the sample and based on the movement of the probe. The distance between the sample and the probe is measured to acquire the three-dimensional information of the surface shape of the sample, and the XY scanning direction when the three-dimensional information is acquired is used as correction data as the correction data. To store the calculated probe scanning trajectory when measuring the physical property value based on the three-dimensional information and the correction data stored in association with each other, and store the calculated probe scanning trajectory, An image reflecting the physical property value of the sample by scanning the probe according to the probe scanning trajectory and measuring the physical property value of the sample based on the movement of the probe. When the obtained image reflecting the physical property value of the sample is acquired thereafter, the probe is scanned according to the stored probe scanning trajectory and the physical property value of the sample is measured based on the movement of the probe. Then, an image reflecting the physical property value of the sample is acquired by a scanning probe microscope.

  ADVANTAGE OF THE INVENTION According to this invention, the scanning probe microscope which acquires the some image reflecting the physical-property value of the sample which is not influenced by temperature drift in a short time is provided.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, an example of a scanning probe microscope that acquires an image reflecting the magnetic force of a sample will be described.

<First embodiment>
FIG. 1 schematically shows a scanning probe microscope (SPM) according to a first embodiment of the present invention.

  As shown in FIG. 1, a scanning probe microscope 10 includes a sample stage 11 on which a sample S is placed, a cantilever 22 having a probe 21 at a free end, a sample S and a probe 21 that are arranged on an X axis, a Y axis, and a Z axis. An XYZ scanner 12 that moves relatively along the axis, a detector 24 that detects the movement of the probe 21 (actually the free end of the cantilever 22), and an excitation that vibrates the cantilever 22 and vibrates the probe 21 The apparatus 23, the calculating part 25 which calculates a scanning track | orbit, the control apparatus 26 which controls the XYZ scanner 12, and the memory 27 which memorize | stores various information are provided.

  The cantilever 22 is held by the vibration device 23. The sample stage 11 is supported by an XYZ scanner 12. The XYZ scanner 12 is fixed to the base 13. The detector 24, the vibration device 23, the control device 26, the memory 27, and the calculation unit 25 are built in the head unit 15 supported by the frame 14 that is fixed to the base 13.

  The XYZ scanner 12 is not limited to this, but may be constituted by a piezoelectric tube scanner, for example. The detector 24 is not limited to this, but may be composed of, for example, an optical system using an optical lever method.

  Two-dimensional scanning (XY scanning) is a combination of main scanning in which the probe is reciprocated at high speed along the main scanning axis with respect to the sample and sub scanning in which the probe is moved at low speed along the sub scanning axis with respect to the sample. Done. Usually, the X axis is set as the main scanning axis, and the Y axis is set as the sub scanning axis.

Since the main scan (X scan) is fast, the influence of temperature drift between the data acquired during one main scan (X scan) is usually negligible. However, since the sub-scan (Y scan) is slow, the data acquired until one sub-scan (Y scan) is completed, that is, until one two-dimensional scan (XY scan) is completed. In some cases, the influence of temperature drift cannot be ignored. In this case, the data acquired at the end of the XY scan includes an error due to a temperature drift during the time required for one XY scan, as compared with the data acquired at the beginning of the XY scan.

  In the XY scanning, depending on the moving direction along the sub-scanning axis, the probe is reciprocated at high speed along the X axis while moving at a low speed in the + Y direction, and the probe is moved along the X axis with respect to the sample. And moving at a low speed in the -Y direction while reciprocating at a high speed. In the following description, the former is called XY scanning in the + Y direction, and the former is called XY scanning in the -Y direction.

  First, an operation for acquiring three-dimensional information of the surface shape of the sample S and correction data for temperature drift will be described.

  The cantilever 22 is vibrated by the vibration device 23, and the probe 21 is vibrated along the Z axis. The movement of the probe 21, that is, the displacement along the Z axis is detected by the detector 24, and changes in the vibration frequency and amplitude of the probe 21 are monitored by the calculation unit 25. In addition, the XYZ scanner 12 brings the distance between the sample S and the probe 21 closer to a distance suitable for detecting the atomic force. In this state, the vibration frequency and amplitude of the probe 21 depend on the distance along the Z axis between the surface of the sample S and the tip of the probe 21. Further, the XYZ scanner 12 is driven along the X axis and the Y axis by the control device 26, and the probe 21 is XY scanned with respect to the sample S. During the XY scanning, the control device 26 drives the XYZ scanner 12 along the Z axis so as to keep the vibration frequency and amplitude of the probe 21 constant, and feeds back the distance between the sample S and the tip of the probe 21. Control (Z-scan). The feedback control amount reflects the distance (including the sample shape and temperature drift) between the surface of the sample S and the tip of the probe 21. This is acquired as the height information (Z value) of the sample S at the position in the XY plane. That is, coordinate data including an X value and a Y value indicating a position in the XY plane and a Z value at the position is acquired. During the XY scanning, the acquisition of the Z value is repeated at a predetermined timing to acquire a large number of (X, Y, Z) coordinate data. The set of coordinate data obtained in this way defines a curved surface reflecting the surface shape of the sample S. A set of coordinate data of these (X, Y, Z) is stored in the memory 27 as three-dimensional information of the surface shape of the sample S. Further, the Y scan direction (+ Y direction or -Y direction) of the probe 21 in the XY scan at that time is stored in the memory 27 in association with the three-dimensional information as Y correction data (+ Y correction data or -Y correction data). For the association, for example, the file name of the three-dimensional information may be a parameter value (+ Y, −Y) in the Y scanning direction of the probe 21 or may be symbolized.

  Next, an operation for detecting the magnetic force of the sample S and acquiring a plurality of images reflecting the magnetic force in succession will be described.

  The cantilever 22 is vibrated by the vibration device 23, and the probe 21 is vibrated along the Z axis. The movement of the probe 21, that is, the displacement along the Z axis is detected by the detector 24, and changes in the vibration frequency and amplitude of the probe 21 are monitored by the calculation unit 25 to detect the magnetic force. While detecting the magnetic force, the probe 21 is moved close to the sample S at a low speed, or the probe 21 is moved away from the state in contact with the sample S so that the magnetic force can be detected stably. The distance between the probes 21 is adjusted. That is, the XYZ scanner 12 adjusts the distance between the sample S and the probe 21 to a distance suitable for detecting the magnetic force. Here, the distance between the sample S and the probe 21 may be a known amount. In this state, the vibration frequency and amplitude of the probe 21 depend on the magnetic force acting between the sample S and the probe 21.

  Here, the sub-scanning direction of the XY scanning of the probe 21 when acquiring the first image is defined as the + Y direction. Next, based on the direction of Y scanning, Y correction data is read from the memory 27, and a scanning trajectory is calculated by the calculation unit 25. (Here, since the Y scanning direction is the + Y direction, + Y correction data is read from the memory 27.) The calculated scanning trajectory is stored in the memory 27. Subsequently, the control device 26 drives the XYZ scanner 12 along the X axis, the Y axis, and the Z axis, and scans the probe 21 with respect to the sample S according to the calculated scanning trajectory. During scanning, a magnetic force is repeatedly detected at a predetermined timing based on changes in the vibration frequency and amplitude of the probe 21, and the detection result is acquired as magnetic force information at that position. An image reflecting the magnetic force of the sample S in the XY scanning in the + Y direction is acquired based on the magnetic force information at a number of positions acquired in this way.

  Next, in order to acquire the second image continuously and efficiently, the Y-scan direction of the probe 21 is changed to the -Y direction. Further, as the Y correction data, -Y correction data is read from the memory 27 in accordance with the Y scanning direction, and a scanning trajectory is calculated by the calculation unit 25. The calculated scanning trajectory is stored in the memory 27. Subsequently, the control device 26 drives the XYZ scanner 12 along the X axis, the Y axis, and the Z axis, and scans the probe 21 with respect to the sample S according to the calculated scanning trajectory. During scanning, a magnetic force is repeatedly detected at a predetermined timing based on changes in the vibration frequency and amplitude of the probe 21, and the detection result is acquired as magnetic force information at that position. An image reflecting the magnetic force of the sample S in the XY scanning in the −Y direction is acquired based on the magnetic force information at a number of positions acquired in this way.

  Thereafter, in the same manner as described above, the Y-scan direction (+ Y direction or −Y direction) of the probe 21 is changed in order, and according to the Y-scan direction (+ Y direction or −Y direction) of the probe 21. The magnetic force is measured while scanning the probe 21 in accordance with the corresponding probe scanning trajectory stored in the memory 27, and the magnetic force of the sample S is determined based on the magnetic force information at a number of positions obtained by the magnetic force measurement. The images that reflect are acquired in order.

  In this embodiment, when acquiring the three-dimensional information of the surface shape of the sample S prior to the measurement of the magnetic force of the sample S, the direction of the Y scan, which is the low-speed sub-scan in the XY scan, is used as correction data for the temperature drift ( (± Y direction) is acquired and stored in association with the three-dimensional information. When measuring the magnetic force of the sample S, the probe scanning trajectory for measuring the magnetic force was calculated based on the stored three-dimensional information and the Y scanning direction (± Y direction) at the first time. The magnetic force of the sample S is measured while scanning the probe 21 according to the probe scanning trajectory, and an image reflecting the magnetic force of the sample S is created based on the measurement result. The probe scanning trajectory calculated in consideration of the Y scanning direction (± Y direction) is free from the influence of temperature drift, so the distance between the tip of the probe 21 and the sample S during magnetic force measurement is optimized. Is done. The calculated probe scanning trajectory is stored. From the second time onward, the stored probe scanning trajectory is read out, the magnetic force of the sample S is measured while scanning the probe 21 according to the probe scanning trajectory, and an image reflecting the magnetic force of the sample S based on the measurement result is obtained. create. Thus, since the three-dimensional information of the surface shape of the sample S is not acquired every time the magnetic force of the sample S is measured, a plurality of images reflecting the magnetic force of the sample S can be acquired in a short time.

  In the present embodiment, the XYZ scanner 12 that moves the sample S constitutes a scanning unit that scans the probe 21 with respect to the sample S. However, the scanning means is not limited to this, and any configuration may be used as long as the probe 21 and the sample S are relatively moved. The scanning unit may be configured by an XYZ scanner that moves the probe 21 along the X axis, the Y axis, and the Z axis. Alternatively, an XY scanner that moves one of the probe 21 and the sample S along the X axis and the Y axis, and a Z scanner that moves the other of the probe 21 and the sample S along the Z axis may be used.

<Second embodiment>
The scanning probe microscope of the present embodiment has basically the same configuration as that of the first embodiment. In the present embodiment, information stored in the memory 27 as correction data is different from that in the first embodiment.

  In the present embodiment, the procedure for acquiring an image reflecting the magnetic force is basically the same as that in the first embodiment. However, in this embodiment, when acquiring the three-dimensional information of the surface shape of the sample S, the Y scan direction (± Y direction) and speed of the XY scan are stored in the memory 27 as correction data for temperature drift. The probe scanning trajectory when measuring the magnetic force is calculated by the calculation unit 25 based on the three-dimensional information stored in the memory 27 in association with each other and the Y scanning direction and speed. The rest is the same as in the first embodiment.

  In this embodiment, when acquiring the three-dimensional information of the surface shape of the sample S prior to the measurement of the magnetic force of the sample S, the direction of the Y scan, which is the low-speed sub-scan in the XY scan, is used as correction data for the temperature drift ( (± Y direction) and speed are stored in association with the three-dimensional information. When measuring the magnetic force of the sample S, the probe scanning trajectory for measuring the magnetic force was calculated based on the stored three-dimensional information and the Y scanning direction (± Y direction) at the first time. The magnetic force of the sample S is measured while scanning the probe 21 according to the probe scanning trajectory, and an image reflecting the magnetic force of the sample S is created based on the measurement result. Since the probe scanning trajectory is calculated in consideration of the speed in addition to the Y scanning direction (± Y direction), the influence of the temperature drift is more preferably eliminated than in the first embodiment, and the magnetic force is being measured. The distance between the tip of the probe 21 and the sample S is optimized. The calculated probe scanning trajectory is stored. From the second time onward, the stored probe scanning trajectory is read out, the magnetic force of the sample S is measured while scanning the probe 21 according to the probe scanning trajectory, and an image reflecting the magnetic force of the sample S based on the measurement result is obtained. create. Thus, since the three-dimensional information of the surface shape of the sample S is not acquired every time the magnetic force of the sample S is measured, a plurality of images reflecting the magnetic force of the sample S can be acquired in a short time.

<Third embodiment>
The apparatus configuration of the scanning probe microscope of this embodiment is basically the same as that of the first embodiment. This embodiment is different from the first embodiment in the method of calculating the scanning trajectory.

  In this embodiment, the scanning trajectory is calculated as a function. For example, assuming that the surface shape of the sample S is a plane, a plane function (for example, e = aX + bY + cZ) is calculated from appropriate three-point coordinate data as a scanning trajectory. The assumed function is not limited to a planar function, and any function may be used as long as it represents the surface shape of the sample S. Further, instead of a function representing the surface shape of the sample S, a function of inclination (for example, Y = aX + b) may be assumed for each of the X scan and the Y scan. That is, the scanning trajectory may be calculated as a single function or a combination of a plurality of functions. Other operations are the same as those in the first embodiment.

  The function of the scanning trajectory may be assumed based on the three-dimensional information (coordinate data of many points) of the surface shape of the sample S stored in the memory 27. Alternatively, at the stage of storing the three-dimensional information in the memory 27, the three-dimensional information may be converted into a function such as a plane by the calculation unit 25 and stored. Further, when the surface shape of the sample S is known in advance, the number of coordinate data necessary for calculating the surface shape is not obtained without acquiring the coordinate data of multiple points as described in the first embodiment. Only coordinate data may be acquired. For example, if the function to be calculated is a planar function, only the coordinate data of three points need be acquired.

  In the present embodiment, the amount of data stored in the memory 27 as the probe scanning trajectory is reduced by using the probe scanning trajectory as a function. In addition, the calculation of the probe scanning trajectory and the scanning control when measuring the magnetic force can be handled easily.

<Fourth embodiment>
FIG. 2 schematically shows a scanning probe microscope according to the fourth embodiment of the present invention. The apparatus configuration of the scanning probe microscope of this embodiment is basically the same as that of the first embodiment. In FIG. 2, members indicated by the same reference numerals as those shown in FIG. 1 are similar members, and detailed description thereof is omitted.

  In the scanning probe microscope of the present embodiment, the calculation unit 25 sets the effective time of the probe scanning trajectory. For this reason, the calculation unit 25 has a clock 31 and a time limit 32. The time limit 32 holds information on the effective time of the probe scanning trajectory calculated by the calculation unit 25. The effective time is determined in consideration of the relationship between temperature change and time.

  Similar to the first embodiment, prior to measurement of the magnetic force of the sample S, three-dimensional information of the surface shape of the sample S is acquired, and the acquired three-dimensional information is stored in the memory 27. Further, the Y-scanning direction when this three-dimensional information is acquired is stored in the memory 27 in association with the three-dimensional information as correction data.

  In the present embodiment, the time information is read from the clock 31 by the calculation unit 25 at the timing of saving the correction data, and the read time information is stored in the memory 27 in association with the correction data.

  Associating the correction data with the time information, for example, the file name of the three-dimensional information may be obtained by adding the time information to the parameter value in the Y scanning direction of the probe 21 or may be symbolized.

  The first measurement of the magnetic force of the sample S is performed as in the first embodiment. In other words, the scanning trajectory is calculated by the calculation unit 25 and the calculated scanning trajectory is stored in the memory 27. While scanning the probe 21 with respect to the sample S according to the calculated scanning trajectory, the magnetic force is repeatedly measured based on changes in the vibration frequency and amplitude of the probe 21 at a predetermined timing.

  The first measurement here refers to the Y scan in the + Y direction and the Y scan in the −Y direction. The second and subsequent measurements in the following description relate to the Y scan in the + Y direction and the Y scan in the −Y direction.

  When the magnetic force of the sample S is measured from the second time onward, first, the calculation unit 25 determines whether to use the scanning trajectory stored in the memory 27. Whether or not to use the scanning trajectory is determined as follows. The time information stored in association with the correction data used for calculating the scanning trajectory is read from the memory 27. Comparing the read time information with the time of the clock 31, the elapsed time of the correction data is calculated. The calculated elapsed time is compared with the effective time held in the time limit 32. When the elapsed time is shorter than the effective time, the scanning trajectory is read from the memory 27 and the magnetic force is measured using the read scanning trajectory, as in the first embodiment. If the elapsed time is longer than the effective time, the magnetic force is measured according to the same procedure as the first measurement.

  FIG. 3 shows a modification of the present embodiment. As shown in FIG. 3, an interface 33 may be provided in the calculation unit 25, and the effective time of the probe scanning trajectory stored in the memory 27 may be set by the user. Instead of leaving the determination to the calculation unit 25, each time the magnetic force of the sample S is measured, the interface 33 displays the acquisition time of the three-dimensional information and the correction data, and the user determines whether or not the probe scanning trajectory can be used. You may make it do.

  In this embodiment, the validity of the scanning trajectory stored in the memory 27 is reviewed based on the elapsed time, in other words, taking into account the change in temperature drift. As a result, the magnetic force can always be measured under suitable conditions.

<Fifth embodiment>
FIG. 4 schematically shows a scanning probe microscope according to the fifth embodiment of the present invention. The apparatus configuration of the scanning probe microscope of this embodiment is almost the same as that of the first embodiment. In FIG. 2, members indicated by the same reference numerals as those shown in FIG. 1 are similar members, and detailed description thereof is omitted.

  The scanning probe microscope of the present embodiment includes a temperature sensor 41 attached to the frame 14 in addition to the configuration of the scanning probe microscope of the first embodiment. The temperature sensor 41 is attached to the frame 14 between the head unit 15 and the base 13. The expansion / contraction amount per 1 ° C. of the probe 21 and the sample S due to the temperature change of the frame 14 is stored in the memory 27 as an expansion / contraction amount coefficient (linear expansion coefficient). This expansion / contraction amount coefficient may be calculated from the measurement result of actual SPM measurement. Alternatively, it may be a function of the thermal expansion coefficient of the frame 14 and the distance between the probe samples.

  Prior to measuring the magnetic force of the sample S, three-dimensional information of the surface shape of the sample S is acquired. Acquisition of the three-dimensional information of the surface shape of the sample S is performed as in the first embodiment. That is, the probe 21 is vibrated by the vibration device 23, the distance between the sample S and the probe 21 is brought close to the distance suitable for detecting the atomic force by the XYZ scanner 12, and the probe 21 is moved with respect to the sample S by the XYZ scanner 12. XY scan. During the XY scanning, the distance between the sample probes is feedback-controlled (Z scanning) by the XYZ scanner 12 so that the vibration frequency and amplitude of the probe 21 are kept constant. The feedback amount is acquired as height information (Z value) of the sample S at a position (X value, Y value) in the XY plane. This is repeated at a predetermined timing to acquire a large number of coordinate data, and these are stored in the memory 27 as three-dimensional information of the surface shape of the sample S. Further, the Y scanning direction (+ Y direction or −Y direction) of the probe 21 in the XY scanning is stored in the memory 27 as Y correction data (+ Y correction data or −Y correction data) in association with the three-dimensional information.

  Also in the present embodiment, as in the first embodiment, when measuring the magnetic force of the sample S, according to the scanning trajectory calculated based on the three-dimensional information stored in the memory 27 and the correction data, The probe 21 is XY scanned with respect to the sample S by the XYZ scanner 12. However, in this embodiment, simultaneously with the scanning by the XYZ scanner 12, the expansion / contraction coefficient is called from the memory 27 by the arithmetic unit 25, the temperature information obtained by the temperature sensor 41 is referred to, and probe scanning is performed in real time (or at regular time intervals). Correct the Z value of the orbit. The correction of the Z value is performed, for example, according to the formula: [Z value after correction] = [Z value before correction] + [expansion / contraction coefficient] × [temperature change amount]. The magnetic force is measured while scanning the probe 21 in accordance with the corrected probe scanning trajectory, and the magnetic force of the sample S is reflected based on the magnetic force information at many positions in the XY plane obtained by the magnetic force measurement. Acquired image.

  In this embodiment, temperature change information that determines the amount of temperature drift is acquired, and the probe scanning trajectory is corrected based on the acquired temperature change information. Thereby, the magnetic force can always be measured using a suitable probe scanning trajectory.

  The embodiments of the present invention have been described above with reference to the drawings. However, the present invention is not limited to these embodiments, and various modifications and changes can be made without departing from the scope of the present invention. Also good.

  In the above-described embodiment, an example of SPM that images the magnetic force of the sample (acquires an image reflecting the magnetic force) has been described. However, the present invention is not limited to this, and other physical property values. It may be an SPM for imaging the image, for example, KFM (Kelvin Probe Force Microscope).

1 schematically shows a scanning probe microscope according to a first embodiment of the present invention. 6 schematically shows a scanning probe microscope according to a fourth embodiment of the present invention. The modification of 4th embodiment of this invention is shown. 6 schematically shows a scanning probe microscope according to a fifth embodiment of the present invention. The positional relationship between the sample and the probe in the scanning probe microscope is shown. 2 shows a sequence of two-dimensional scanning, that is, XY scanning in a scanning probe microscope.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Scanning probe microscope, 11 ... Sample stage, 12 ... XYZ scanner, 13 ... Base, 14 ... Frame, 15 ... Head part, 21 ... Probe, 22 ... Cantilever, 23 ... Excitation equipment, 24 ... Detector, 25 DESCRIPTION OF SYMBOLS ... Calculation part 26 ... Control apparatus 27 ... Memory 31 ... Timepiece 32 ... Time limit 33 ... Interface 41 ... Temperature sensor

Claims (19)

It is a scanning probe microscope that acquires an image reflecting the physical property value of the sample,
A cantilever with a probe at the free end;
Scanning means for scanning the probe with respect to the sample;
Detecting means for detecting movement of the probe;
Storage means for storing three-dimensional information of the surface shape of the sample and correction data for temperature drift in association with each other;
A calculation means for calculating a probe scanning trajectory when measuring the physical property value based on the three-dimensional information and the correction data;
When the image reflecting the physical property value of the sample is first acquired, the scanning means is two-dimensionally scanned to acquire the three-dimensional information and the correction data, and the acquired three-dimensional information and the correction The probe scanning trajectory is calculated by the computing means based on the data, the calculated probe scanning trajectory is stored in the storage means, and the probe is scanned by the scanning means in accordance with the calculated probe scanning trajectory. Obtain an image that reflects the physical property values,
When acquiring an image reflecting the physical property value of the sample thereafter, an image reflecting the physical property value of the sample by scanning the probe according to the probe scanning trajectory stored in the storage unit. Acquire a scanning probe microscope.   The scanning probe microscope according to claim 1, wherein the correction data is a sub-scanning direction of the two-dimensional scanning.   The scanning probe microscope according to claim 1, wherein the correction data is a sub-scanning direction and speed of the two-dimensional scanning.   The scanning probe microscope according to claim 1, wherein the probe scanning trajectory is a function.   The scanning probe microscope according to claim 1, wherein the calculation unit sets an effective time of the probe scanning trajectory.   The scanning probe microscope according to claim 1, wherein the calculation unit corrects the probe scanning trajectory based on temperature.   The scanning probe microscope according to claim 1, wherein the physical property value is a magnetic force. It is a scanning probe microscope that acquires an image reflecting the physical property value of the sample,
A cantilever with a probe at the free end;
Scanning means for scanning the probe with respect to the sample;
Detecting means for detecting movement of the probe;
Storage means for storing three-dimensional information of the surface shape of the sample and correction data for temperature drift in association with each other;
Calculating means for calculating a probe scanning trajectory when measuring the physical property value based on the three-dimensional information stored in the storage means and the correction data corresponding thereto;
When the image reflecting the physical property value of the sample is first acquired, the scanning unit performs XY scanning on the sample along the XY plane by the scanning unit, and based on the movement of the probe obtained by the detection unit. Then, the distance between the sample and the probe is measured to obtain three-dimensional information on the surface shape of the sample, and the three-dimensional information is obtained using the XY scanning direction when the three-dimensional information is obtained as the correction data. And the probe scanning trajectory when measuring the physical property value based on the three-dimensional information and the correction data stored in association with each other. And the calculated probe scanning trajectory is stored in the storage means, and the probe is scanned in accordance with the calculated probe scanning trajectory. Acquires an image that reflects the physical properties of the sample by measuring the physical properties of the sample based on the movement of the probe obtained by the detection means as well as scanned by,
When an image reflecting the physical property value of the sample is acquired thereafter, the probe is scanned by the scanning unit according to the probe scanning trajectory stored in the storage unit, and the probe obtained by the detection unit is scanned. A scanning probe microscope that obtains an image reflecting the physical property value of the sample by measuring the physical property value of the sample based on movement.   9. The storage unit stores, as the correction data, a Y-scan direction that is slower than the X-scan among the X-scan along the X-axis and the Y-scan along the Y-axis in the XY scan. Scanning probe microscope.   The storing means stores the + Y direction and the −Y direction in Y scanning as the correction data in association with the three-dimensional information in XY scanning in the + Y direction and the three-dimensional information in XY scanning in the −Y direction, respectively. The scanning probe microscope according to claim 9.   The scanning probe microscope according to claim 8, wherein the storage unit stores a scanning speed as correction data in addition to the scanning direction.   The scanning probe microscope according to claim 9, wherein the storage unit stores the scanning speed of the Y scan as correction data in addition to the direction of the Y scan.   11. The scanning according to claim 10, wherein the storage unit stores the scanning speed at the time of the + Y scanning and the scanning speed at the time of the −Y scanning as correction data in addition to the + Y scanning direction and the −Y scanning direction, respectively. Type probe microscope.   The scanning probe microscope according to claim 8, wherein the calculation unit determines whether to use the probe scanning trajectory stored in the memory when acquiring an image reflecting the physical property value of the sample. .   The calculation unit includes a time limit for holding an effective time of the probe scanning trajectory, and compares the effective time with the elapsed time from the time when the correction data used for calculating the probe scanning trajectory is acquired. The scanning probe microscope according to claim 8, wherein it is determined whether or not to use a probe scanning trajectory.   The scanning probe microscope according to claim 8, wherein the calculation unit calculates the probe scanning trajectory as a function.   A temperature detection unit that detects a temperature of a structure existing between the probe and the sample; and the calculation unit corrects the probe scanning trajectory based on a temperature detected by the temperature detection unit. The scanning probe microscope according to claim 8. It is a method of acquiring an image reflecting the physical property value of a sample by a scanning probe microscope,
When acquiring an image reflecting the physical property value of the sample for the first time, the probe is two-dimensionally scanned to acquire three-dimensional information on the surface shape of the sample, and the three-dimensional information and the direction of the two-dimensional scan are obtained. Based on calculating the probe scanning trajectory and storing it, scanning the probe according to the probe scanning trajectory to obtain an image reflecting the physical property value of the sample,
A scanning probe microscope that acquires an image reflecting the physical property value of the sample by scanning the probe according to the stored probe scanning trajectory when acquiring an image reflecting the physical property value of the sample thereafter A method for acquiring an image reflecting the physical property value of a sample. It is a method of acquiring an image reflecting the physical property value of a sample by a scanning probe microscope,
When the image reflecting the physical property value of the sample is first acquired, the probe is XY scanned along the XY plane with respect to the sample, and the distance between the sample and the probe is determined based on the movement of the probe. Measurement is performed to obtain three-dimensional information of the surface shape of the sample, and the XY scanning direction at the time of obtaining the three-dimensional information is stored as the correction data in association with the three-dimensional information and stored in association with each other. A probe scanning trajectory for measuring the physical property value is calculated based on the three-dimensional information and the correction data, the calculated probe scanning trajectory is stored, and the probe is scanned according to the probe scanning trajectory And measuring the physical property value of the sample based on the movement of the probe to obtain an image reflecting the physical property value of the sample,
When an image reflecting the physical property value of the sample is acquired thereafter, the probe is scanned according to the stored probe scanning trajectory and the physical property value of the sample is measured based on the movement of the probe. A method of acquiring an image reflecting a physical property value of a sample by a scanning probe microscope, acquiring an image reflecting the physical property value of the sample.

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