JPH0915137A - Frictional force measuring apparatus and scanning frictional force microscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To measure various frictional forces acting between a probe and the surface of a sample without causing any damage on the surface of sample. SOLUTION: In a frictional force measuring apparatus and a scanning frictional force microscope, a probe 3 provided on a cantilever 1 is brought into contact with a sample surface 11 at a predetermined contact pressure and separated therefrom. When the probe 3 is touching the sample surface 11, the probe 3 and sample 11 are displaced or oscillated laterally along the sample surface. Displacement of the cantilever 1 caused by the interaction of the probe 3 and sample 11 is measured and a signal indicative of the frictional force between the probe and sample is generated therefrom. Subsequently, the probe is shifted sequentially to a plurality of measuring points on the sample surface and the frictional force is determined at each measuring point and the distribution thereof is imaged as required. A laser light source 21 for irradiating the surface ∥of cantilever 1 with a light beam and a quadripartite light receiving element 13 for receiving the reflected light are also provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a frictional force measuring device and a scanning frictional force microscope, and particularly to various types including maximum static frictional force by appropriately moving and scanning a probe provided on a cantilever with respect to a sample. It relates to a technology that enables measurement of frictional force.

[0002]

2. Description of the Related Art Conventionally, there has been known a friction force microscope which measures a frictional force between a probe and a sample surface at each point on the sample surface and forms a two-dimensional image of the distribution of the frictional force. The frictional force microscope measures the frictional force by measuring the amount of torsion of the cantilever caused by the frictional force generated between the sample surface and the probe provided near the tip of the cantilever in the atomic force microscope. be able to. That is, the probe and the sample surface are moved relative to each other while the probe is in contact with the sample surface with a constant contact pressure. The frictional force can be measured from the amount of torsion of the cantilever during this movement. Further, in this case, the deflection of the cantilever is also measured at the same time, and two-dimensional image data corresponding to the surface shape of the sample can be obtained as an atomic force microscope. In such a conventional friction force microscope, the probe is always in contact with the sample surface, and the probe is raster-scanned while being in contact with the sample surface. Therefore, the conventional friction force microscope measures the dynamic friction force.

[0003]

In the conventional friction force microscope, as described above, a constant force is applied between the probe and the sample surface in order to measure the frictional force between the probe and the sample surface. There is a need. This force is greater than the force used in conventional atomic force microscopes. Therefore, when the probe is scanned with respect to the sample surface, the sample surface may be damaged, for example, scratched on the sample surface. Alternatively, the scanning of the probe causes inconveniences such as peeling of molecules and the like adhering to the sample surface or sweeping out of molecules and particles.

Therefore, in view of the above-mentioned problems of the conventional example, an object of the present invention is to provide a frictional force measuring device and a scanning frictional force microscope capable of measuring the frictional force while removing or reducing the damage on the sample surface. To provide.

Another object of the present invention is to provide a frictional force measuring device and a scanning frictional force microscope capable of measuring the frictional force in various states including the maximum static frictional force while removing or reducing the damage on the sample surface. To provide.

[0006]

To achieve the above object, according to the present invention, in a frictional force measuring device, a probe provided on a cantilever is brought into contact with and released from a sample surface at a predetermined contact pressure. A drive mechanism that relatively displaces or vibrates the probe and the sample along the sample surface while the probe is at least in contact with the sample surface, and a cantilever created by the interaction between the probe and the sample. And a signal processing means for generating a signal indicating the frictional force between the probe and the sample from the output of the displacement measuring means.

In the frictional force measuring device according to the above structure, the probe is brought into contact with the measurement point on the sample surface with a predetermined contact pressure by the drive mechanism, and the probe and the sample are contacted while the probe is in contact with the sample surface. And are relatively displaced or vibrated along the sample surface or in the lateral direction. In this case, the direction of the cantilever perpendicular to the sample surface (Z direction), the lateral direction along the sample surface (X
The movement in the (-Y direction) can be carried out in three ways: moving the cantilever with respect to the sample, moving the cantilever and the sample together, or moving the sample side, but any of them can be used. By moving the probe and the sample surface relative to each other along the sample surface while the probe is in contact with the sample surface, the interaction between the probe and the sample, that is, friction causes the torsion of the cantilever. The displacement measuring means measures the displacement of the cantilever caused by such a twist. From the magnitude of this displacement, the signal processing means generates a signal indicating the frictional force between the probe and the sample. When the cantilever is moved in the lateral direction, the maximum static friction force is obtained from the maximum displacement of the cantilever with the tip of the probe stationary with respect to the sample surface. When the tip of the probe slides on the sample surface, the dynamic frictional force between the probe and the sample can be measured.

In this case, the probe is sequentially moved relative to a plurality of measurement points on the sample surface so that the probe comes into contact with and separates from the sample surface at each measurement point, and at least the probe is at the sample surface. By relatively displacing or vibrating the probe and the sample along the sample surface while in contact with, the distribution of the frictional force at a plurality of measurement points on the sample surface can be obtained.

Further, it is convenient that the displacement measuring means measures the amount of twist and the amount of bending of the cantilever. In this case, the frictional force can be measured from the amount of deflection while maintaining the contact pressure of the probe against the sample surface at a predetermined value based on the amount of twist of the cantilever. The dynamic friction force can also be measured by determining the amount of deflection when the probe is slipping on the sample surface.

Further, the displacement measuring means can be constituted by a light source such as a laser light source for irradiating the cantilever with a light beam and a four-division sensor for detecting reflected light of the light beam via the cantilever. The amount of twist and the amount of flexure of the cantilever can be detected by mutually calculating the signals corresponding to the received light intensity obtained from each sensor section of the four-division sensor. The surface of the cantilever may be mirror-finished in order to reflect the light beam from the laser light source, or a mirror or the like may be attached to the cantilever.

Further, the maximum static friction force can be measured by providing a means for obtaining the maximum value of the amount of torsion of the cantilever generated by the static friction force between the probe and the sample. The means for obtaining the maximum value of this twist amount is
For example, a top value holder or a bottom value holder for holding the peak level or the bottom level of the output from the displacement measuring means can be used.

Further, according to the present invention, there is provided a scanning friction force microscope, which moves a probe provided on a cantilever sequentially to a plurality of measurement points relative to a sample surface. And a drive mechanism for contacting the probe with the sample surface at a predetermined contact pressure so that the probe and the sample are relatively displaced or vibrated along the sample surface while the probe is at least in contact with the sample surface. Displacement measurement that measures the displacement of the cantilever produced by the interaction between the probe and the sample when the probe and the sample are relatively displaced or vibrated along the sample surface while the needle is in contact with the sample surface. And a signal processing means for generating from the output of the displacement measuring means two-dimensional image data indicating the frictional force between the probe and the sample at a plurality of measurement points.

In such a scanning friction force microscope, the drive mechanism causes the probe provided on the cantilever to come into contact with and separate from the sample surface at a predetermined contact pressure, and the probe at least contacts the sample surface. In addition to the operation of displacing or vibrating the probe and sample relatively along the sample surface while in contact, the probe provided on the cantilever is sequentially moved to multiple measurement points relative to the sample surface. It also has the function of moving. By such an action, the displacement measuring means measures the displacement of the cantilever at a plurality of points on the sample surface, and the frictional force between the probe and the sample at the plurality of measuring points is obtained. Then, the signal processing means generates two-dimensional image data showing the frictional force at the plurality of measurement points. This two-dimensional image data is displayed as an image by a display device such as a CRT display,
Alternatively, the image data is supplied to a printer to be printed, or an image corresponding to the image data is printed. Alternatively, the two-dimensional image data is supplied and stored in a magnetic disk device, an optical disk device, or the like.

Further, the scanning friction force microscope can easily function as an atomic force microscope only by changing the control procedure of the driving mechanism and the like. For example, while the probe provided on the cantilever is moved and scanned by the drive mechanism to a plurality of measurement points on the sample surface, the displacement due to the deflection of the cantilever is obtained by the displacement measuring means.
As a result, two-dimensional image data corresponding to the surface shape of the sample can be obtained, and it becomes possible to evaluate the sample surface as an atomic force microscope.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1A shows the external appearance of a cantilever with a probe used in a frictional force measuring device and a scanning frictional microscope according to the present invention, with the tip of the probe facing up. ing. As shown in the figure, a probe 3 is attached to the tip of a cantilever 1 formed of an elongated plate member. In addition, the rear end of the cantilever is the connecting member 5.
It is fixed to a fixing member or the like not shown via. Such a cantilever and a probe are produced by a lithography technique using, for example, silicon nitride. In this embodiment, the length of the cantilever is about 200 μm and the height of the probe is about 6 μm.

1 (b) and 1 (c) respectively show
The state in which the cantilever 1 and the probe 3 are viewed from the side and the front is shown, and in these figures, the case where the cantilever is not bent is shown. Also, in these figures, the arrows indicate the path of a light beam such as a laser beam for measuring the twist and deflection of the cantilever. Reference numeral 7 indicates an incident light beam, and 9 indicates a reflected light beam.

FIG. 1 (d) shows a state in which the cantilever 1 is deflected, and the deflection amount is detected by the amount by which the reflected direction of the reflected light beam 9 is deviated from the direction shown in dotted line when there is no deflection. it can.

Further, FIG. 1E shows a state in which the cantilever 1 is twisted, and the reflected light beam 9
Will shift left and right when viewed from the front of the cantilever,
The amount of twist of the cantilever 1 can be measured from the amount of deviation of the light beam.

Next, referring to FIG. 2, a method for measuring the frictional force in the frictional force measuring device and the scanning frictional force microscope according to the present invention will be described. FIG. 2A shows the relationship between the frictional force between the probe and the sample surface when the probe attached to the cantilever is laterally vibrated while being in contact with the sample surface. 2B shows the state of torsion of the cantilever with respect to the lateral displacement of the cantilever at points A to H in the graph of FIG.

First, as shown by A in FIG. 2B, in the initial state in which the probe is in contact with the sample surface, the frictional force is zero, and the cantilever tilts, and therefore the twist is also zero.

Next, as shown in B, when the cantilever is laterally displaced (the sample may be displaced), a frictional force is generated between the probe and the sample surface, and the cantilever is twisted. In this state, a static frictional force equal to or less than the maximum static frictional force is exerted between the probe and the sample surface, and therefore slippage between the probe and the sample surface does not occur.

When the cantilever is further displaced laterally in the same direction, as shown in C, the torsion of the cantilever reaches the maximum. In this state, the maximum static frictional force acts between the probe and the sample surface.

Further, when the cantilever is displaced in the same lateral direction, the torsion of the cantilever is reduced as shown in D, and slip occurs between the probe and the sample. In this state, a dynamic frictional force is acting between the probe and the sample surface.

Next, when the direction of the lateral movement of the cantilever is reversed, the torsion of the cantilever is gradually eliminated, and eventually, as indicated by E, it becomes zero and the frictional force becomes zero. When the cantilever is further displaced in the opposite direction, the cantilever is twisted in the opposite direction as indicated by F. When the cantilever is further displaced, as shown in G, the torsion of the cantilever reaches the maximum value. In this state, the maximum static frictional force acts on the probe and the sample surface.

When the change of the cantilever is further increased, as shown in H, the torsion of the cantilever decreases,
A slip occurs between the probe and the sample, and a state in which a dynamic friction force is applied is reached.

When the lateral direction of movement of the cantilever is reversed again from the H state, the torsion of the cantilever gradually decreases and eventually becomes zero. In such a process, the maximum value of the cantilever twist is measured and recorded. Note that this process may be repeated several times at the same measurement point.

FIG. 3 shows the relationship between the lateral displacement width of the probe and the frictional force. As shown in (a), when the displacement width of the probe is small, the measured static friction force may not reach the maximum static friction force.

On the other hand, if the displacement width of the probe is sufficiently large, as shown in (b), the frictional force between the probe and the sample reaches the maximum static frictional force, and then the sliding frictional force is generated. Becomes In addition, if the displacement width of the probe is too large, the sliding width between the probe and the sample surface becomes large as shown in (c), and the sample may be damaged as in the conventional friction force microscope. Get higher Therefore, it is necessary to appropriately control the displacement width of the probe according to the type of frictional force that needs to be measured.

Next, the measurement of the frictional force using the optical lever method will be described with reference to FIG. FIG. 4 is an enlarged view of the cantilever 1 provided with the probe 3 as seen from the front side of the tip of the cantilever, and 11 indicates the sample surface. Also, 7
Indicates a light beam projected onto the upper surface of the cantilever 1 from a laser light source (not shown), and 9 indicates its reflected light. Reference numeral 13 denotes a light receiving element that receives the reflected light 9.

In FIG. 4, when the lateral displacement of the cantilever is Δx, the torsion angle of the cantilever is θ, and the height from the tip of the probe to the surface of the cantilever 1 is h, the following relationship is established.

[Formula 1] Δx / h = SIN (θ)

At this time, the reflected light 9 from the cantilever 1
Is inclined by 2θ. Light receiving element 1 for receiving the reflected light 9
Let L be the distance between 3 and the cantilever.
The displacement Δa of the reflected light 9 on the light receiving surface of is expressed by the following equation.

[Formula 2] Δa / L = SIN (2θ)

On the other hand, the frictional force F between the probe 3 and the sample 11 is the spring constant k and the torsion angle θ with respect to the torsion of the cantilever 1.
From and it is expressed as follows.

[Equation 3] F = k · θ

The torsion angle θ of the cantilever is small and SI
N (θ) is approximately equal to θ, so SIN (2θ)
When the approximation holds that is approximately equal to 2θ, the frictional force F is as follows from these equations.

(4) F = (k / 2L) Δa

Therefore, the frictional force F has a proportional relationship with the displacement Δa of the reflected light 9 on the light receiving element 13.

Further, in the arrangement of the optical lever shown in FIG. 1, the directions of change of the reflected light azimuth due to the bending and the twist are orthogonal to each other, and by using the four-division sensor as the light receiving element 13, the bending amount and The amount of twist can be detected independently.

That is, as shown in FIG. 5, the four-division sensor has four photodiodes A, B, C, and D arranged vertically and horizontally.
The outputs of the photodiodes A to D change according to the position of the spot 15 of the light beam of the reflected light 9 from the cantilever 1. The outputs of the photodiodes A, B, C, and D are the same symbols A, B, C, and
When expressed by D, the amount of deflection of the cantilever 1 can be calculated by the following equation.

[Equation 5] (A + B)-(C + D)

The amount of twist of the cantilever 1 can be calculated as follows.

[Equation 6] (A + C)-(B + D)

In the present invention, the deflection amount of the cantilever 1 is used to control the contact of the probe with the sample surface at a predetermined pressure, and the twist amount of the cantilever 1 is used to measure the frictional force. doing.

In the above structure, the cantilever is displaced laterally when the probe is in contact with the sample surface. However, the lateral displacement of the sample with respect to the probe causes the probe to contact the sample surface. You may always vibrate when not doing. In this case, when the probe comes into contact with the sample and the contact pressure is low at the beginning, the frictional force acting between the probe and the sample is also small, so the probe and sample easily exceed the small maximum static friction force. Start sliding. When the contact pressure is further increased, the maximum static friction force is also increased and the sliding range is reduced. When a given contact pressure is reached, the maximum static friction force is also maximized and this value is recorded. This measurement mode enables high-speed image acquisition. However, the frequency of lateral vibration needs to be set sufficiently higher than the frequency of contact-release.

FIG. 6 shows a schematic structure of a scanning frictional force microscope according to the present invention using the above-described frictional force measuring method. In the apparatus shown in FIG. 6, the cantilever 1 having the probe 3 as described above is fixed to a fixing member (not shown) such as a base of a microscope via a connecting member 5. The position of the sample 11 is controlled in three dimensions, and
A piezoelectric actuator 19 that vibrates in a lateral direction that generates a frictional force with respect to the probe 3 is also used. The piezoelectric actuator 19 is also used for scanning the X and Y axes and for controlling the displacement in the Z axis direction in order to keep the amount of deflection of the cantilever 1 constant.

Further, as described above, in order to detect the displacement of the cantilever 1 by the optical lever method, the laser light source 21 for irradiating the surface of the cantilever 1 with a light beam and the reflected light of the light beam from the cantilever 1 are received. A four-division light receiving element or a four-division sensor 13 is provided. A deflection component calculation circuit 23 and a twist component calculation circuit 25 are connected to the output of the four-division light receiving element 13.

The flexure component calculation circuit 23 calculates the output of the four-division light-receiving element 13 from the output of the four-division light-receiving element 13 by, for example, the calculation of the above equation 5.
Generates an output signal proportional to the deflection of cantilever 1,
It is supplied to the operational amplifier 27 and the control device 29. The twist component calculation circuit 25 outputs the output of the four-division light receiving element 13
For example, according to the above formula 6, an output signal proportional to the twist component of the cantilever 1 is generated and supplied to the control device 29. The twist component calculation circuit 25 also includes a top value holder and a bottom value holder circuit that output the maximum value and the minimum value of the voltage proportional to the twist of the cantilever 1, respectively. These top value holder and bottom value holder circuits can be configured using, for example, a well-known peak hold circuit.

The operational amplifier 27 is also supplied with a signal from the scanning signal generator 31 controlled by the controller 29 and a signal from the lateral displacement signal generator 33 controlled by the controller 29. The operational amplifier 27 generates a control signal for driving the piezoelectric actuator 19 based on the signals from these circuits 23, 31, 33. The control device 29 performs all controls and control related to acquisition of data, and a display device 37 is connected to the control device 29 for displaying the acquired data. The display device 37 is, for example, a CRT display device, a liquid crystal display device, or the like.

In the scanning friction force microscope of FIG. 6, the control signal generated by the scanning signal generating circuit 31 is supplied to the piezoelectric actuator 19 through the operational amplifier 27 under the control of the control device 29. The sample 11 is sequentially scanned relative to the probe 3. In addition, the piezoelectric actuator 1 is controlled by the control signal from the scanning signal generation circuit 31.
9 is driven so that the sample 11 and the probe 3 are brought into contact with each other at each measurement point and separated from each other. In this case, the contact pressure of the probe 3 with respect to the surface of the sample 11 is detected by the deflection component calculation circuit 23 from the signal obtained by the optical lever method using the laser light source 21 and the four-division light receiving element 13, and the control device 29 is used. Is fed back to control the cantilever 1 so that the amount of deflection is constant.

Further, at each measurement point, the lateral displacement signal generation circuit 3
By applying the signal generated by 3 to the piezoelectric actuator 19 via the operational amplifier 27, the probe 3 and the sample 11 are laterally vibrated. The twist component of the cantilever 1 generated by this vibration is detected by the twist component calculation circuit 25 from the four-division light receiving element 13 and is controlled by the control device 29.
Is input to In this case, the torsion component calculation circuit 25 also outputs a voltage proportional to the maximum value of the torsion of the cantilever, and thereby a signal indicating the maximum static friction force can be obtained.

The control device 29 obtains any or all of the above-mentioned frictional force at each measurement point of the sample 11, that is, the maximum static frictional force and the dynamic frictional force, and stores it in the internal storage device. Then, the data read out from the storage device later is displayed as an image on the display device 37 or is printed. Therefore, for example, the maximum static friction force at each point (X, Y) on the sample 11 can be imaged and displayed on the CRT display.

Each circuit in FIG. 6 is preferably composed of a dedicated electronic circuit in order to operate at a high speed, but a sufficiently high speed microcomputer operates a plurality of or all circuits. It is also possible to perform. An advantage of using a computer such as such a microcomputer is that the scanning procedure and various parameters can be changed by a program relatively easily. Further, it is possible to make the selection of parameters and the like intuitive and easy to understand by devising a user interface.

Since the apparatus of FIG. 6 has a function of controlling the probe 3 to contact the surface of the sample 11 with a constant contact pressure, the piezoelectric actuator 1 for performing such control.
The control signal to 9 can be used as data representing the height of the sample surface at each measurement point, and it is also possible to obtain data on the shape of the sample surface as a so-called atomic force microscope.

Therefore, in the microscope of FIG.
It is possible to simultaneously obtain data including the maximum static frictional force and dynamic frictional force at each measurement point, data indicating the height of the sample surface, etc., and these data are stored in the control device 29 for each measurement point or externally attached. It is also possible to store the data in this memory device and to analyze the data in this memory device precisely by the controller 29 or another computer and display it in the form of an image.

[0050]

EXAMPLE In the configuration example of FIG. 6, the cantilever 1 having a length of 200 μm with a probe having a height of 6 μm was used. Further, as the sample 11, an organic silane molecular film locally formed on a line on silicon is used, and the cantilever probe 3 has the same molecule as the sample in order to increase the interaction with the sample surface. Was used, which was surface-treated with an organic silane such as trimethylchlorosilane or octadecyltrichlorosilane. Using such a sample and a probe, the maximum static friction force at each point (X, Y) on the sample was measured, imaged and displayed on a CRT display device.

[0051]

As described above, according to the present invention, various frictional forces with respect to the contact pressure applied between the probe and the sample can be accurately measured in a short time while minimizing damage to the sample surface. can do. In particular, it becomes possible to accurately detect the maximum static friction force that could not be measured by the conventional friction force microscope in a short time, and it is possible to obtain data on various friction force distributions of the sample, and more accurate measurement of the sample is possible. It becomes possible to make an evaluation.

Further, the scanning friction force microscope according to the present invention can be realized by making a slight modification to the conventional friction force microscope, and the increase in the cost of the apparatus can be minimized.

Further, since the scanning frictional force microscope according to the present invention can have the function of an atomic force microscope, the frictional force at each measurement point is measured and the data on the height of the sample surface are obtained at the same time. Thus, the shape and frictional force distribution of the sample surface can be obtained, and an extremely sophisticated analytical evaluation means such as a nanometer surface analysis means for analyzing a surface modified with a molecule can be provided.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing the structure and operation of a probe with a cantilever used in a frictional force measuring device and a scanning frictional force microscope according to the present invention.

FIG. 2 is an explanatory diagram showing a relationship between twisting and frictional force of the cantilever with a probe shown in FIG.

FIG. 3 is an explanatory graph showing the relationship between frictional force and displacement of a cantilever probe and a sample.

FIG. 4 is an explanatory diagram showing the principle of the optical lever method.

FIG. 5 is an explanatory diagram showing a method of detecting each displacement of the cantilever by the four-division light receiving element.

FIG. 6 is a block diagram showing a schematic configuration of a scanning frictional force microscope according to the present invention.

[Explanation of symbols]

 1 cantilever 3 probe 5 mounting member 7 light beam 9 reflected beam 11 sample 13 light receiving element 15 light beam spot 19 tube type piezoelectric actuator 21 laser light source 23 deflection component calculator 25 twist component calculator 27 operational amplifier 29 controller 31 scanning signal Generator 33 Lateral displacement signal generator 37 Display device

Claims (7)

[Claims] 1. A probe provided on a cantilever is brought into and out of contact with a sample surface at a predetermined contact pressure, and the probe and the sample are contacted with each other while the probe is at least in contact with the sample surface. Drive mechanism for relatively displacing or vibrating the sample along the sample surface, displacement measuring means for measuring the displacement of the cantilever produced by the interaction between the probe and the sample, and the probe from the output of the displacement measuring means. And a signal processing means for generating a signal indicating a frictional force between the sample and the sample, and a frictional force measuring device. 2. The probe is sequentially moved relative to a plurality of measurement points on the sample surface, and the probe is brought into contact with and separated from the sample surface at each measurement point, and at least the probe is a sample. The distribution of the frictional force at a plurality of measurement points is obtained by displacing or vibrating the probe and the sample relatively along the sample surface while in contact with the surface. The frictional force measuring device described. 3. The frictional force measuring device according to claim 1, wherein the displacement measuring means is capable of measuring the amount of twist and the amount of bending of the cantilever. 4. The displacement measuring means includes a light source for irradiating a cantilever with a light beam, and a four-division sensor for detecting reflected light of the light beam by the cantilever, and a light-receiving intensity of each sensor section of the four-division sensor. The frictional force measuring device according to claim 3, wherein the amount of twist and the amount of flexure of the cantilever are detected based on the above. 5. The maximum static friction force can also be measured by providing a means for obtaining the maximum value of the amount of torsion of the cantilever generated by the frictional force between the probe and the sample. The frictional force measuring device according to any one of claims 1 to 4. 6. The probe provided on the cantilever is sequentially moved to a plurality of measurement points relative to the sample surface, and the probe is brought into contact with the sample surface at a predetermined contact pressure at each measurement point. A drive mechanism that relatively displaces or vibrates the probe and the sample along the sample surface while at least in contact with the sample surface; and a probe and the sample while the probe is in contact with the sample surface. Displacement measuring means for measuring the displacement of the cantilever produced by the interaction between the probe and the sample when relatively displaced or vibrated along the sample surface, and the probe at a plurality of measurement points from the output of the displacement measuring means. A scanning friction force microscope comprising: a signal processing unit that generates two-dimensional image data indicating a frictional force between a needle and a sample. 7. The scanning friction force microscope according to claim 6, which further functions as an atomic force microscope.