JPH06201315A - Scanning type probe microscope device - Google Patents

Abstract

PURPOSE:To provide a scanning type probe microscope device for easily executing accurate setting and estimation of the interval between a sample and a probe, and for carrying out probe scanning at a fixed interval between the sample and the probe. CONSTITUTION:The expanding operation of an XYZ driving piezoelectric body 27 on which a sample 26 is loaded, is controlled by a microcomputer 21, and the body can be moved in any directions X, Y, Z in a very fine mode. The front end part of a cantilever 31 is moved closer to the surface of the sample, and scanning is carried out at predetermined vibration (an amplitude signal S2) or non-vibration (a displacement signal S1) by means of an excitation piezoelectric body 32. The central value of the displacement of the probe detected by an MFM (scanning type magnetic microscope), and a dependency curve of the interval between the vibration amplitude value of the probe and the sample probe is measured. The two curves are processed into image, and the vibration amplitude value in the measurement of an isodynamic force grading image is set, while the interval between the sample and the probe in measurement of a constant-height image is set and estimated, and the displacement thus obtained is displayed on an image screen by a host computer 22.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface information separating apparatus for forming surface information by synthesizing individual information obtained by separating a plurality of surface information of the same sample.

[0002]

2. Description of the Related Art In general, there is a scanning probe microscope which forms an image from surface information obtained by scanning the surface of a sample with a cantilever which has a predetermined natural vibration.

For example, the atomic force microscope proposed in Japanese Patent Laid-Open No. 63-309802 scans with a cantilevered needle having a pointed tip close to the sample surface up to a distance where an atomic force can be generated. Then, the shift is detected from the natural frequency of the frequency of the cantilever needle that is generated by being affected by the atomic force. Here, the detected shift of the frequency is used as information indicating the distance between the tip of the cantilever needle and the sample surface, and an image of the sample surface is formed. Further, by attaching magnetic powder to the tip of the cantilever needle, it can be used as a scanning magnetic force microscope (MFM) capable of obtaining magnetic force information of a sample.

Regarding the method for detecting the shift of the natural frequency of the cantilever needle described above, the root of the cantilever is excited with a constant vibration amplitude in FIG. 9, and the vibration frequency at the tip of the probe is the vertical axis with the excitation frequency as the horizontal axis. The vibration characteristics of the above-described cantilever will be shown and described.

FIG. 9A shows the natural frequency f of the cantilever that is not affected by the force from the sample, for example, the magnetic force.
A vibration characteristic of 1 is shown. In Fig. 9 (b), the distance between the sample probe is reduced, and the probe is Lennard-
The characteristic is that the natural frequency is reduced to f2 according to the value of the force gradient based on the distance dependency of the force due to the influence of Jones Potential's attractive force, electrostatic attractive force, magnetic force, and the like.

Further, as shown in FIG. 9 (c), when the sample stage is brought close to the probe and the attractive force acting between the sample probes exceeds the force of the cantilever spring, the tip of the probe is suddenly drawn into the sample surface. , The tip of the probe comes into contact with the sample, and the vibration amplitude becomes “0” in the entire frequency band.

Then, the root of the cantilever showing such an approach characteristic is vibrated with a constant amplitude by a sine wave of the excitation frequency f3, and the sample is brought close to the probe. When the change in the vibration amplitude at the tip of the probe at that time is made to correspond to the sample position, the characteristic becomes as shown in FIG.

Next, FIG. 11 shows the structure of a conventional scanning magnetic force microscope, which will be described.

In this scanning magnetic force microscope, the cantilever 8 vibrates by the vibrating piezoelectric body 9. The probe displacement detection unit 10 detects the displacement of the probe unit at the tip of the cantilever 8 and outputs a displacement signal S1 to the amplitude detection unit 11.

The amplitude detecting section 11 applies a sine wave signal S3 for exciting the cantilever 8 to the vibrating piezoelectric body 9.
Further, the amplitude detector 11 lock-in detects a signal having the same frequency as the sine wave signal S3, and outputs the amplitude signal S2 to one end of the differential amplifier 12. At the other end, a constant power source 1
3 is connected.

The host computer 2 stores the measurement data transferred from the microcomputer (hereinafter referred to as a microcomputer) 1 and forms an image. The microcomputer 1 performs measurement through the X control unit 4 and the Y control unit 5 while controlling the XYZ driving piezoelectric body 7 to perform two-dimensional scanning, and transfers the measurement data to the host computer 2. This measurement method includes constant magnetic force gradient measurement and constant height measurement.

In the constant magnetic force gradient measurement, the differential amplifier 12 takes a difference signal between the amplitude signal S2 and the set value of the constant power source 22, and the z control section 3 sets the difference signal to "0". , The XYZ piezoelectric body 7 is expanded and contracted in the Z direction. That is, Z control is performed so that the amplitude signal S2 is maintained at a constant value, and the Z control data Vz is taken in via the microcomputer 1 to be measured data.

On the other hand, in the constant height measurement, the root of the vibrating cantilever 8 is fixed and read from the surface of the sample 6, and the signal output from the A / D converter 3 after A / D conversion, that is, the amplitude signal. Let S2 be the measurement data.

Further, a method of detecting a phase shift of the displacement signal S1 from the sine wave signal S3 by using a phase detector instead of the amplitude detector 11 to detect the shift of the natural frequency of the cantilever is also used. Sometimes.

[0015]

However, the above-mentioned MF
In the M measurement, the sample position dependency of the vibration amplitude of the probe is obtained in a memory scope or the like, and from this dependency, the value of the vibration amplitude to be set is read in the constant magnetic force gradient measurement,
Based on the read value, the control target value (set value of the constant power source 22) is set.

In the case of constant height measurement, a specific inter-probe distance is set on the basis of this distance dependence curve. These procedures are accompanied by the risk of malfunction due to reading errors by the measurer.

Further, it is necessary to stop or control the fine movement mechanism in the z direction in order to accurately set the distance between the sample tips, but with respect to the change in the distance between the sample tips due to the scanning of the sample having an inclination. For this reason, laborious work such as correcting the inclination of the sample according to the change of the vibration amplitude signal is required.

Therefore, an object of the present invention is to provide a scanning probe microscope apparatus capable of easily setting and estimating the distance between sample probes easily and performing scanning of the probe at a constant distance between sample probes. To do.

[0019]

In order to achieve the above object, the present invention provides a cantilever having a sharp probe portion, a means for detecting displacement of the probe portion, and a resonance characteristic of the probe portion. Means for detecting changes, means for controlling and driving the sample in three dimensions, means for storing surface information of the sample,
In a scanning probe microscope composed of a means for arithmetically processing a plurality of the surface information and a means for forming an image of the surface information, first surface information consisting of force information acting on the sample and a non-vibrating probe. And the dependence of the second surface information consisting of magnetic force gradient information on the sample interprobe distance using a probe that vibrates in a predetermined manner are measured at the same time, and either the first surface information or the second surface information is measured. Provided is a scanning probe microscope apparatus which controls a sample probe interval based on the crab.

[0020]

In the scanning probe microscope apparatus having the above-described structure, the dependence curve of the distance between the center value of the displacement of the probe detected by the MFM and the vibration amplitude value of the probe between the sample probes is obtained. The measurement is performed, two curves are imaged, and the vibration amplitude value is set in the measurement of the isomagnetic force gradient image and the inter-probe distance between sample probes is set and estimated in the constant height image measurement. Further, the probe scanning plane for the constant height image measurement of a flat sample is detected by using the estimation of the sample position, and the probe is scanned at a constant sample probe-to-probe distance.

[0021]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 shows the configuration of a scanning probe microscope apparatus as a first embodiment according to the present invention, which will be described.

In this scanning probe microscope apparatus,
Microcomputer (hereinafter referred to as microcomputer) 21
Is provided with a host computer 22 that forms an image from the detected surface information. Also, the microcomputer 21
Controls the Z control unit 23, the X control unit 24, and the Y control unit 25 to expand / contract the XYZ driving piezoelectric body 27 on which the sample 26 is placed, thereby moving the sample 26 in any X, Y, and Z directions. Make a slight movement.

The XYZ drive piezoelectric body 27 is provided on a sample stage coarse movement section 29 controlled by a coarse movement control section 28. By moving the XYZ drive piezoelectric body 27, the sample 26 is moved. A big move of.

The sample stage coarse movement unit 29 is mounted on the main body 30, the main body column is provided upward, and the cantilever 31 is provided.

The cantilever 31 is provided so that the pointed tip is brought close to the surface of the sample 26, and is attached via a vibrating piezoelectric body 32 and a coarse cantilever actuator 33. The cantilever coarse movement actuator 33 is driven by a lever position control unit 34 controlled by the microcomputer 1 to move the position of the cantilever 31.

The cantilever 31 is vibrated by the vibrating piezoelectric body 32, and the displacement of the tip portion of the cantilever 31 which has a predetermined vibration or does not vibrate due to the scanning on the sample surface is detected by the probe displacement detector 35. Displacement signal S1
Is output to the amplitude detector 36 and the A / D converter 37.

The amplitude detecting section 36 is provided with the vibrating piezoelectric body 3
A sine wave signal S3 for exciting the cantilever 31 is output to 2, and a signal having the same frequency as the sine wave is detected by the lock-in amplifier and output to the A / D converter 37 as an amplitude signal S2. Under the control of the microcomputer 21, the amplitude detector 36 can output the amplitude signal S2 or stop the amplitude signal S2.

The A / D conversion section 37 is the microcomputer 2
By the control of 1, it is possible to select and output either the displacement signal S1 or the amplitude signal S2.

The microcomputer 21 uses the X control unit 2
4. The Y control unit 25 is controlled to perform measurement while the XYZ driving piezoelectric body 27 is two-dimensionally scanned on the cantilever 31, and the displacement of the cantilever 31 is transferred to the host computer 22 as measurement data. The host computer 22 stores the measurement data transferred from the microcomputer 21, forms an image, and outputs it for display.

Next, FIG. 2 shows a force curve and a probe vibration amplitude curve with respect to the movement of the sample by the scanning probe microscope apparatus configured as described above, and a flowchart and a diagram of the coarse movement approach sequence shown in FIG. The measurement operation of the scanning probe microscope apparatus will be described with reference to the flowchart of the fine movement approach sequence shown in FIG.

The operation of this coarse movement approach will be described with reference to FIG.

At the time of measurement, the fine movement range (± Vzm in the z direction) of the sample 26 placed on the xyz driving piezoelectric body 27 is measured.
In order to bring the tip probe part of the cantilever 31 into ax), the sample 26 is roughly moved.

First, the position of the probe portion is detected by the probe displacement detector 35, and its output signal S1 is set to the reference point of "0", for example (step S1). Next, the host computer 2
The approach switch shown on the screen 2 is designated by a mouse or the like not shown, and the microcomputer 21 is instructed to start the coarse movement approach operation (step S2).

Then, the z-fine-movement signal Vz of the xyz fine-movement piezoelectric body 27 is set so that there is room for separating the sample 26 from the probe, for example, "0" (step S3). A signal for causing the sample 26 to move a certain amount in the direction in which the sample 26 approaches the tip probe of the cantilever 31 is output to the sample stage coarse moving unit 29 (step S4).

Next, the displacement signal S1 is converted into A by the AD conversion section 37.
It is D-converted, and it is determined whether the obtained signal exceeds the set value (step S5). In this determination, if the set value is not exceeded (NO), the process returns to step S4 and the displacement signal S
When 1 exceeds the set value (YES), the z fine movement signal Vz of the xyz driving piezoelectric member is set to −Vzmax, and the sample 26
The distance between the probe and the probe is set to the farthest point in the fine movement range of the sample (step S6), and the coarse movement approach operation is ended.

Next, the sample 26 is replaced with an xyz driving piezoelectric body 27.
2 is a diagram showing a method of obtaining a force curve shown in FIG. 2A and a sample position (Vz) versus probe vibration amplitude (amplitude signal S2) curve shown in FIG. This will be described with reference to the flowchart of the approach operation of No. 4.

First, as described in the conventional example, a sine wave signal S3 that causes the tip probe portion of the cantilever 31 to vibrate with a constant amplitude V1 is sent from the amplitude detector 36 to the vibrating piezoelectric body 32 in a predetermined manner. Amplitude Vmod is applied (step S11) By this application, the probe displacement detector 35 detects the displacement of the probe portion and outputs a displacement signal S1. The amplitude detector 36 detects the amplitude of the displacement signal S1 and outputs an amplitude signal S2 corresponding to the amplitude. At this time, the z-direction fine movement signal Vz of the xyz driving piezoelectric body 27 that has finished the coarse movement approach
Is -Vzmax. That is, as shown in FIG. 10, the value of the amplitude signal S2 is V1 when the z-direction fine movement signal is −Vmax.

Next, the Vz signal output from the z controller 23 is scanned between -Vmax and Vmax. The values of the displacement signal S1 and the amplitude signal S2 at this time are A / D converted by the A / D converter 37 in synchronization with the scanning. The values of the AD-converted displacement signal S1 and amplitude signal S2 are stored in the microcomputer 2
It is sent to the host computer 22 via 1 and is displayed or stored as a graph on the display screen of the host computer 22 with the value of the Vz signal as the horizontal axis (step S12). This operation is repeated a predetermined number of times (step S13).

By such scanning, the sample position (Vz) vs. probe displacement (displacement signal S1) curve shown in FIG. 2A, a so-called force curve, and the sample position (V) shown in FIG.
z) Two characteristics of the probe vibration amplitude (amplitude signal S2) curve are obtained. Then, as the dependence curve measurement, the maximum value in the direction in which the sample 26 moves away from the cantilever 31 is set as the z fine movement signal Vz (step S14), and the measured z is measured.
The dependency curves are displayed on the host computer 22 (step S15).

Next, it is judged whether or not the constant magnetic force gradient image or the constant height MFM image is to be measured (step S
16) If no measurement is made (NO), another measurement or another operation is performed (step S17).

Next, the image to be measured is set (step S18). That is, the measurement of the isomagnetic force gradient image (step S1
9) or the measurement of the constant height MFM image (step S24) is determined.

First, the case where step S19 is selected and an isomagnetic force gradient image is measured will be described.

When measuring the isomagnetic force gradient image, it is necessary to control the amplitude signal S2 to be constant. Therefore, the height of the vertical axis on the sample position (Vz) vs. probe oscillation amplitude (amplitude signal S2) curve (FIG. 2B) obtained by the operation of step S15 is S2 by the mouse or the like on the host computer 22. V2 of the axis is designated (step S20).

Next, the amplitude signal S2 is monitored while moving the output signal Vz of the Z controller 23 set to -Vzmax in the direction in which the sample 26 approaches the probe (step S21). When the monitored amplitude signal S2 reaches the set value of V2, Vz controlled by the microcomputer 21 is switched to an automatic control operation in which the value of V2 is held by the amplitude signal S2 (step S2
2).

Further, the Vz signal is fetched in synchronization with the scanning signals output from the X control unit 24 and the Y control unit 25,
An isomagnetic force gradient image is obtained by displaying at a location corresponding to the XY signal (step S23).

Next, the case of measuring a constant height MFM image will be described. In this constant height MFM image, the height of the cantilever 31 is kept constant and the change in the amplitude signal S2 of the probe portion is measured, and it is necessary to set the height of the cantilever 31 constant.

Therefore, the sample position on the horizontal axis on the sample position (Vz) vs. probe vibration amplitude (S2) curve obtained in step S15 is displayed by the host computer 22 as shown in FIG. The setting position t5 of the Vz axis is designated by the mouse or the like (step S25).

Next, in accordance with an instruction from the microcomputer 21, -Vz
The output signal Vz of the Z control unit 23 set to max is changed until it reaches the value of t5, and the value of Vz is fixed at t5 (step S26). Furthermore, the amplitude signal S is synchronized with the scanning signals output from the X control unit 24 and the Y control unit 25.
2 is fetched and displayed on the host computer 22 or on the display device at a position corresponding to the XY axes to obtain a constant height MFM (step S27).

As described above, the setting is performed with reference to the characteristic curve shown in FIG. 5 on the host computer 22, and the setting is directly connected to the control of the apparatus through the microcomputer, so that the artificial malfunction can be avoided. it can.

Next, a scanning probe microscope apparatus as a second embodiment of the present invention will be described. The configuration of the second embodiment is the same as that of FIG. 1, but the measurement operation is different. The force curve and the cantilever position dependence curve of the force gradient signal with respect to the movement of the cantilever shown in FIG. 5, the coarse movement approach sequence flowchart shown in FIG. 6, and the fine movement approach sequence flowchart shown in FIG.

This scanning probe microscope apparatus is similar to the first embodiment in that the tip probe part of the cantilever 31 is brought into the fine movement range of the sample 26 mounted on the xyz driving piezoelectric body 27, so that the sample 26 Make a coarse movement approach. This operation is almost the same as in the first embodiment. However, in step S6 of FIG. 3 described above, the Vyz signal output from the z control unit 4 was used to move the xyz driving piezoelectric body 27 in the z direction in order to increase the distance between the sample and the probe. The probe may be moved to a position farther than the fine movement range of the sample by using the Vtip signal output from the control unit 34.

Then, the cantilever 31 is scanned in the z direction, and the force curve shown in FIG.
A method for obtaining the sample position (Vz) vs. probe vibration amplitude (S2) curve shown in FIG.

First, as described in the first embodiment, a sine wave signal S3 that causes the tip probe portion of the cantilever 31 to vibrate with a constant amplitude V1 is sent from the amplitude detector 36 to the vibrating piezoelectric body 32. It is given with a predetermined amplitude Vmod (step S3
1).

Then, the z-direction fine movement signal Vtip of the cantilever coarse movement actuator 33 which has finished the coarse movement approach.
Is at the position U1 beyond the fine movement range of the sample 26 as shown in FIG. At the stage where this coarse movement approach is completed, when the sample 26 and the probe are sufficiently separated (that is, the z-direction fine movement signal is at the position U1), as in the first embodiment,
The value of the amplitude signal S2 is V1.

Next, the Vtip signal output from the lever position control section 34 is scanned between the position U1 and the position U3. At this time, the values of the probe displacement signal S1 and the probe amplitude signal S2 are synchronized with the scanning, and the A / D converter 37 performs A / D conversion.
Convert.

The values of the displacement signal S1 and the amplitude signal S2 which have been A / D converted are sent to the host computer 22 via the microcomputer 21, and the value of the Vtip signal is taken as the horizontal axis to the host computer 22. Graphed or stored on the display screen of (step S3
2).

Such an operation is repeated a predetermined number of times (step S33).

By such scanning, the cantilever position (Vtip) vs. probe displacement (S1) curve shown in FIG.
So-called force curve and cantilever position (Vtip) vs. probe vibration amplitude (amplitude signal S2) shown in FIG.
Two characteristics of the curve are obtained. Then, the cantilever coarse movement signal Vtip at the start of the approach is returned to (step S
34) The measured z-dependence curve is displayed on the host computer 22 (step S35). Next, it is judged whether or not the constant magnetic force gradient image or the constant height MFM image is to be measured (step S36).
O), another measurement or another operation is performed (step S3).
7).

Next, the image to be measured is set (step S38). That is, the measurement of the isomagnetic force gradient image (step S3
9), or the measurement of the constant height MFM image (step S44) is determined.

First, the measurement of the isomagnetic force gradient image will be described (step S39).

Similar to the first embodiment described above, in order to measure the isomagnetic force gradient image, the cantilever position (Vz) vs. probe oscillation amplitude (amplitude) shown in FIG. 5B obtained by the operation of step S35. The height of the vertical axis of the signal S2) curve is displayed on the host computer in FIG. 5 (b), and the setting position V2 of the S2 axis is designated by a mouse or the like (step S40).

Next, the lever position control unit 34 at the position U1
The amplitude signal S2 is monitored while moving the output signal Vtip of (1) in the direction in which the sample 26 approaches the probe (step S41). The amplitude signal S2 has a preset V
When the value becomes 2, Vz controlled by the microcomputer 21
Is switched to the automatic control operation in which the amplitude signal S2 maintains the value of V2 (step S42).

Finally, the Vz signal is fetched in synchronization with the scanning signal to be finally output from the X control unit 24 and the Y control unit 24, and displayed at a place corresponding to the XY signal to obtain an isomagnetic force gradient image. (Step S43).

Next, the case of measuring a constant height MFM image will be described. This constant height MFM
In the image, the height of the cantilever 31 is kept constant and the change in the vibration amplitude signal S2 of the probe portion is measured, and the height of the cantilever 31 needs to be set constant.

First, the sample position on the S1 axis of the Vtip vs. S1 curve (FIG. 5A) on the host computer 22 obtained by the operation of step S35 is considered to be the position of W0 where the force curve is horizontal. To be

Then, the height W2 of the cantilever 31 based on the sample position (W0) of the S1 axis is designated by the mouse or the like (step S45). Next, in response to an instruction from the microcomputer 21, the output signal Vtip of the lever position control unit 34 is changed to the displacement signal S1 and the W1 signal is changed to the signal
The value of Vt is changed to 2 as shown in FIG.
The value of the ip signal is fixed at position U5 (step S4)
6).

Further, the amplitude signal S2 is fetched in synchronization with the scanning signals output from the X control section 24 and the Y control section 25, and displayed on the host computer 22 or on the display device at a position corresponding to the XY axes. Thus, a constant height MFM image is obtained (step S47).

As described above, in the scanning probe microscope apparatus of the second embodiment, since the position of the sample is confirmed by using the probe displacement signal and the distance is set by the displacement measurement value, It is possible to set and estimate the distance between sample tips.

Next, a scanning probe microscope apparatus as a third embodiment according to the present invention will be described. In the above-described second embodiment, the height of the probe from the sample was set at one point on the xy plane region, but when the sample tilt is taken into consideration, X
The distance between the sample and the probe changes in accordance with the Y scanning.

Therefore, in this scanning probe microscope apparatus, in order to know the inclination of the sample plane in the scanning area, the dependency curve obtained in the second embodiment is used as the minimum in the measuring area as shown in the flowchart of FIG. The measurement is performed at three or more points, the average plane of the sample surface is calculated, and the height is set from the plane to perform constant height image measurement while keeping the distance between the sample probes constant.

First, a square for indicating the two-dimensional area of the measurement plane is displayed on the screen of the host computer 22 as shown in FIG. 7B, including the scanning range and the scanning direction (step S51).

Next, at least three points in the square are designated as sampling points with a mouse or the like (step S52). The measurement point (P
An XY control signal corresponding to the coordinates (1, P2, ...) Is applied (step S53).

Next, as described in the first embodiment, a sine wave signal S3 that causes the tip probe of the cantilever 31 to vibrate with a constant amplitude V1 is sent from the amplitude detector 36 to the vibrating piezoelectric body 32. It is given with a predetermined amplitude Vmod (step S5
4). Then, the cantilever coarse movement signal Vtip is scanned with a predetermined amplitude and offset. Further, in synchronization with this scanning signal, the amplitude signal S2 (with the displacement signal S1) is stored or displayed on the screen of the host computer 22 (step S55).

Next, the cantilever coarse movement signal Vtip
Scanning is repeated until a predetermined number of times (step S
56) When the predetermined number of times is reached, the cantilever coarse movement signal Vtip at the start of the approach is restored (step S5).
7).

Then, all the measurement points P shown in FIG.
It is determined whether scanning of 1, P2, ... Is performed (step S5
8) If not completed (NO), step S5
When the process returns to step 3 and ends (YES), the cantilever coarse motion signal Vtip, sample position (Vz), probe displacement (displacement signal S1) curve of each measurement point is displayed on the screen of the host computer 22 together with the xy coordinates in the measurement area. It is displayed above (step S59).

Then, the probe position [W2 (P
, P2, ...)] is set (step S60). xy
The plane to be scanned is calculated based on the height set at each point (step S61). XY of the plane obtained by this calculation
The amplitude signal S2 is recorded and displayed in synchronization with the scanning,
Obtain a constant height MFM image (step S6)
2). In this scanning probe microscope apparatus, in order to realize the displacement in the z direction of the plane obtained by calculation,
The xyz drive piezoelectric signal Vz or the cantilever coarse actuator drive signal Vtip may be used.

By this operation, the inclination of the sample can be accurately known by a simple pre-operation, so that the variation of the vibration amplitude of the probe can be changed with respect to the inclined sample while keeping the distance between the sample probes constant. It can be measured.

Further, FIG. 8 shows, as a fourth embodiment, a scanning probe microscope constructed so that the respective constituent members shown in the above-mentioned first, second and third embodiments have some independent functions. Shows the device. Here, of the constituent members of the fourth embodiment, which perform the same functions and operations as the members of FIG. 1, the same reference numerals are given and only the characteristic portions will be described.

In this scanning probe microscope apparatus,
The A / D converter 37 shifts the displacement signal S1, at a predetermined timing.
It has a function of A / D converting the amplitude signals S2 and Vz signals and transferring them to the host computer 22. The X scanning circuit 43 and the Y scanning circuit 44 communicate with the host computer 22 at least at the timing of data acquisition during scanning.

Further, the coarse movement control section 28 has at least A /
The coarse movement can be turned on and off by using the displacement signal S1 captured by the D conversion unit 37 as a criterion. The lever position control unit 34 exchanges with the host computer 22 at least the timing of scanning the base of the cantilever 31 in the z direction.

Then, the voltage source 47 serving as the reference potential of the differential amplifier 46 is controlled to have a voltage corresponding to the value of the set vibration amplitude. The output from the differential amplifier 46 is input to the automatic control circuit 48. In the automatic control circuit 48, xyz is set so that the input value becomes "0".
The z direction of the driving piezoelectric body 27 is automatically controlled.

Further, the scanning circuit 41 determines the timing when the sample 26 is scanned in the z direction by the host computer 2
2 can be exchanged, and a value can be swung in a direction in which the sample 26 is moved away from the probe from an arbitrary position by a command from the host computer 22. Further, the oscillator 45 vibrates the tip of the probe by exciting the cantilever 31, and the host computer 2
It can be turned on and off by the command from 2.
Further, as described in the conventional example, it can be realized by using a phase detector instead of the amplitude detector 36.

With this configuration, the measurements of the first, second and third embodiments can be realized.

As described above, according to the scanning probe microscope apparatus of the present invention, in the scanning probe microscope that extracts the information of the sample by using the vibration of the cantilever by the method of approaching the sample, between the sample tips. Setting the control amount for measurement based on the sample position dependence of the displacement of the cantilever that reflects the working force and the distance dependence of the probe vibration amplitude signal that reflects the force gradient between the sample tips from the sample surface And, it becomes possible to set the sample probe interval with high accuracy and without error.

Further, the sample position can be detected by scanning the cantilever side, and the sample probe distance can be set with higher accuracy.

Further, by measuring the distance dependence at a plurality of points in the measurement region and measuring the inclination of the sample, when there is an inclination on the surface of the sample, a constant sample probe interval corresponding to the inclination of the sample is obtained. It is possible to measure changes in physical property information of.

Further, although the present invention has been described with reference to the scanning magnetic force microscope (MFM) in the above-mentioned embodiments, the invention is not limited to the MFM, and a natural vibration of the cantilever such as a van der Waals force microscope or an electrostatic force microscope is generated. Applicable to general scanning probe microscopes that detect weak forces that affect the cantilever by detecting a number of tufts, and that various modifications and applications are possible without departing from the scope of the invention. Of course.

[0089]

As described in detail above, according to the present invention, a scanning probe capable of easily and accurately setting and estimating a sample probe distance and performing probe scanning at a constant sample probe distance. A microscope device can be provided.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a scanning probe microscope apparatus as a first embodiment according to the present invention.

FIG. 2 is a diagram showing a force curve and a probe vibration amplitude curve with respect to movement of a sample.

FIG. 3 is a flowchart showing a coarse movement approach sequence of the first embodiment.

FIG. 4 is a flowchart showing a fine movement approach sequence of the first embodiment.

FIG. 5 is a diagram showing a force curve and a cantilever position dependence curve of a force gradient signal with respect to movement of a cantilever of a scanning probe microscope apparatus as a second embodiment.

FIG. 6 is a flowchart showing a coarse movement approach sequence of the second embodiment.

FIG. 7 is a flowchart showing a fine movement approach sequence of the scanning probe microscope apparatus as the third embodiment.

FIG. 8 is a diagram showing a configuration of a scanning probe microscope apparatus as a fourth embodiment according to the present invention.

FIG. 9 is a diagram showing a vibration characteristic of a cantilever depending on an excitation frequency and a vibration amplitude of a tip of a probe.

FIG. 10 is a diagram showing a relationship between a change in vibration amplitude at the tip of a probe and a sample position.

FIG. 11 is a diagram showing a configuration of a conventional scanning magnetic force microscope.

[Explanation of symbols]

1, 21 ... Microcomputer, 2, 2
2 ... Host computer, 3, 23 ... Z control unit, 4, 2
4 ... X control unit, 5, 25 ... Y control unit, 6, 26 ... Sample,
7, 27 ... XYZ driving piezoelectric body, 8, 31 ... Cantilever, 9, 32 ... Exciting piezoelectric body, 10, 35 ... Probe displacement detecting section, 11, 36 ... Amplitude detecting section, 12 ... Differential amplifier, 13
... constant power source, 14, 37 ... A / D conversion unit 28 ... coarse movement control unit, 29 ... sample stage coarse movement unit, 30 ... main body, 33 ... cantilever coarse movement actuator.

Claims (1)

[Claims] 1. A cantilever having a pointed probe,
Means for detecting displacement of the probe portion, means for detecting changes in resonance characteristics of the probe portion, means for controlling and driving the sample in three dimensions, and means for storing surface information of the sample, In a scanning probe microscope including a means for arithmetically processing a plurality of the surface information and a means for forming an image of the surface information, first surface information consisting of force information acting on the sample and a vibration-free probe. Also, the dependence of the second surface information, which is composed of gradient information of the magnetic force on the sample interprobe distance, is measured at the same time using a probe that vibrates in a predetermined manner, and either the first surface information or the second surface information A scanning probe microscope apparatus characterized by controlling a sample probe interval based on a crab.