JPH06323845A - Thin film force detection probe for scanning force microscope - Google Patents

Abstract

PURPOSE:To simplify the detector for detecting the force on the surface of a sample at the tip of a cantilever beam in a scanning force microscope by employing a microforce sensor for converting the displacement directly into a signal, having such structure as a functional thin film is formed on the cantilever beam while being sandwiched by electrodes, in place of a displacement gauge for measuring the displacement at the tip of the cantilever beam. CONSTITUTION:The thin film force detection probe comprises a first thin film, i.e., a thin film elastic body 1, having a chip 1a at the tip thereof, a layer structure 2 of at least three layers, i.e., an electrode 2a, a second thin film 2b, and an electrode 2c, formed sequentially on the thin film elastic body 1, and a capacitance detector 3 for converting the capacitance between the electrodes 2a, 2c into a voltage signal and detecting the capacitance, wherein the second thin film is formed such that the capacitance between the electrodes is varied depending on the bending stress being applied thereon. This structure simplifies the force detector for scanning force microscope and facilitate the constitution of scanning force microscope for special environment.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scanning probe microscope such as a scanning tunnel microscope for imaging a fine texture or structure on the surface of a sample by utilizing the interaction between the surface and the probe. The present invention relates to a thin film type force detection probe for a scanning force microscope, which detects a displacement of a probe that changes according to a change in force due to surface irregularities or the like, based on a change in electrical characteristics of a thin film formed on the probe.

[0002]

2. Description of the Related Art In a typical conventional scanning force microscope, as shown in FIG. 9, a sample 36 to be measured is placed on a piezoelectric scanning body 32 capable of scanning in three axes (XYZ) directions. A cantilever 30a having a tip 30b at its tip, which is arranged so as to be able to face the sample 36, is fixed on a support base 35 on which the piezoelectric scanning body 32 is supported. Then, a displacement detection system 30c for detecting the displacement near the tip of the cantilever 30a is connected to the support base 35 via the alignment mechanism 30d behind the cantilever 30a (on the side opposite to the sample 36). It is arranged in this way. In other words, the force detection system of the conventional scanning force microscope uses a cantilever 30a that converts surface irregularities into leverage.
And a displacement detection system 30c that converts the displacement of the lever on the cantilever 30a into an electric signal. The displacement detection system 30c is, for example, a tunnel tip of a scanning tunneling microscope, or an optical displacement system called a light beam composed of a laser irradiation system and a split photodiode, and in any case, an alignment mechanism 30d. It is necessary to adjust the position by.

Further, a signal corresponding to the displacement of the cantilever 30a is received from the displacement detection system 30c, and a scanning control signal in the Z-axis direction (vertical direction, normal to the surface of the sample 36) is sent to the piezoelectric scanning body 32. A feedback control system 31 is provided. Further, a scanning signal generator 33 for sending out scanning signals in the XY directions (horizontal direction, in-plane two directions of the sample 36) of the piezoelectric scanning body 32, an input signal from the scanning signal generator 33 and a feedback control system 31.
Display 34 that displays images based on signals from
Is provided. With such a configuration, the following operation is performed in the conventional scanning force microscope. First, the sample 36 is moved in the Z (vertical) direction by the piezoelectric scanning body 32 and brought close to the tip 30b at the tip of the cantilever 30a. Then, when the sample 36 and the chip 30b come into contact with each other and the chip 30b receives a repulsive force from the surface of the sample 36, the cantilever 30a is displaced.

Since the repulsive force acting on the tip 30b from the surface of the sample 36 is a function of the distance between the sample 36 and the cantilever 30a, the sample 36 is moved in the XY (horizontal) directions by the piezoelectric scanning body 32. If it is made, cantilever 30a depending on the unevenness of sample 36
The displacement of changes. And, for example, constant force (constant interval)
In the measurement method which can be called a mode, the sample on the piezoelectric scanning body 32 is supplied by the XY scanning signal from the scanning signal generator 33.
While scanning 36 in the XY directions, based on the detection signal from the displacement detection system 30c, the piezoelectric scanning body 32 is displaced in the Z direction by the Z control signal from the feedback control system 31 so that the detection signal becomes constant. . Then, the XY scanning signal and Z
The function of displaying an image corresponding to the unevenness information of the sample surface on the display 34 is performed from the control signal.

[0005]

However, in the conventional scanning force microscope as described above, the force detection system includes a cantilever for converting unevenness of the sample surface into a displacement of the lever and a tip of the cantilever. Since it has a displacement detection system that detects displacement and converts it into an electric signal, there are problems that it becomes complicated and the device becomes large. Further, since it is composed of two systems, there is a problem that the adjustment of the device becomes quite difficult. The present invention is intended to solve such a problem, and the force from the sample surface acting on the tip of the cantilever is directly used as a signal for the displacement without using a displacement meter for measuring the displacement of the tip. By using a micro force sensor having a structure in which a functional thin film sandwiched between electrodes on a cantilever that can be converted is used, a device for detecting the force on the sample surface can be simplified. An object is to provide a thin film type force detection probe for a scanning force microscope.

[0006]

In order to achieve the above-mentioned object, the thin-film force detection probe for a scanning force microscope of the present invention is mounted as a force detection system of a scanning force microscope to obtain information on the force on the sample surface. To obtain, a thin film elastic body made of a first thin film having a tip at the tip, an electrode on the thin film elastic body,
The second thin film has a layer structure of at least three layers mounted in the order of a second thin film and an electrode, and a capacitance detector for converting the electric capacitance between the electrodes of the layer structure into a voltage signal for detection. The thin film is characterized by being formed as a thin film that changes the electric capacitance between the electrodes according to the bending stress received by the thin film. The second thin film is formed as a thin film having piezoelectricity.

Further, it is characterized in that it is provided with a piezoelectric body excitation mechanism for externally exciting and vibrating the cantilever composed of the thin film elastic body and the layer structure as described above.
Further, the layer structure is formed so as to be equally divided into two in the width direction, and the capacitance detector has two input systems so that the capacitance of each of the divided second thin films can be independently detected. It is characterized by having A charge detector for converting the charge output from the second thin film having the layer structure into a voltage signal for detection is provided, and the output signal from the second thin film is supplied to either the charge detector or the capacitance detector. It is characterized in that switching means for selectively connecting to one side is provided.

Further, the charge detector has two input portions so that the charge output of each of the divided second thin films can be detected independently, and the output signal from the second thin film is supplied to two. Both systems are characterized in that switching means for selectively connecting to either one of the charge detector and the capacitance detector is provided. Further, one end of a cantilever composed of the thin film elastic body and the layer structure is supported by a silicon wafer, and the capacitance detector is integrally formed on the silicon wafer.

Alternatively, the thin-film force detection probe for a scanning force microscope of the present invention is attached as a force detection system of a scanning force microscope, and a first thin film having a tip at the tip for obtaining information on the force on the sample surface. A thin film elastic body, a layer structure of at least three layers mounted on the thin film elastic body in the order of the electrode, the second thin film, and the electrode, and a change in electric resistance between the electrodes of the layer structure is converted into a voltage signal. And a resistance detector for detecting, wherein the second thin film is formed as a thin film that changes the electrical resistance between the electrodes according to the bending stress received by the second thin film. The second thin film is formed as a thin film having piezoelectricity.

Further, it is characterized in that it is provided with a piezoelectric body excitation mechanism for externally exciting and vibrating the cantilever composed of the thin film elastic body and the layer structure as described above.
Further, the layer structure is formed so as to be divided into two equal parts in the width direction, and the resistance detector has two systems so that the change in the electric resistance of each of the divided second thin films can be independently detected. It is characterized by having an input section. A charge detector for converting the charge output from the second thin film having the layered structure into a voltage signal for detection is provided, and the output signal from the second thin film is supplied to either the charge detector or the resistance detector. It is characterized in that switching means for selectively connecting to one side is provided. In addition, each of the divided second
In order to detect the charge output of the thin film independently, the charge detector has two input systems, and the output signal from the second thin film is supplied to both the charge detector and the resistance detector for both systems. It is characterized in that switching means for selectively connecting to one of them is provided.

Further, one end of the cantilever composed of the thin film elastic body and the layer structure is supported by a silicon wafer,
The silicon wafer is characterized in that the resistance detector is integrally formed. And the chip is
It is characterized in that it is formed of a minute projection whose tip is sharpened. In addition, the first thin film is formed of a silicon oxide film or a nitride film, and the second thin film is formed.
Is characterized by being formed of a zinc oxide thin film. Further, a thin insulating film is formed on the surface of the outermost electrode of the layer structure.

[0012]

In the thin-film force detection probe for a scanning force microscope according to the present invention described above, the second layered structure mounted on the thin-film elastic body is used.
The signal corresponding to the bending stress applied to the thin film is detected as a change signal of the electric capacitance between the electrodes by the capacitance detector connected to the layer structure. And the second
When the thin film of 1 has both piezoelectricity, a function corresponding to the AC displacement of the cantilever composed of the thin film elastic body and the layer structure is detected by the capacitance detector or the charge detector connected to the layer structure. Done. Further, when the layer structure is divided, an action of independently detecting the electric capacitance or the output charge of each second thin film is performed. Alternatively, a function of detecting a signal corresponding to the bending stress received by the second thin film of the layer structure attached to the thin film elastic body as a change signal of the electric resistance between the electrodes by the resistance detector connected to the layer structure is provided. Done.

When the second thin film also has piezoelectricity, a signal corresponding to the AC displacement of the cantilever composed of the thin film elastic body and the layer structure is supplied to the resistance detector or the resistance detector connected to the layer structure. The action of detection is performed by the charge detector. Also, when the layer structure is divided,
The function of independently detecting the electric resistance of each second thin film is performed. Further, by applying a voltage to the second thin film having piezoelectricity, the cantilever is vibrated with a required amplitude. Further, the piezoelectric excitation mechanism acts to vibrate the cantilever with a required amplitude.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIGS. 1 to 4 show a thin film type force detection probe for a scanning force microscope as a first embodiment, and FIG. 2, FIG. 2 is a perspective view of a main part thereof, FIG. 3 is a scanning force microscope using the same, FIG. 4 is a characteristic diagram thereof, and FIGS. 5 and 6 are thin-film force detection for a scanning force microscope as a second embodiment. 5 shows a probe, FIG. 5 is a configuration diagram thereof, FIG. 6 is a scanning force microscope using the same, FIG. 7 is a plan view of a thin film type force detection probe for a scanning force microscope as a third embodiment, and FIG. FIG. 8 is a configuration diagram of a thin film type force detection probe for a scanning force microscope as a fourth embodiment. Further, FIG. 10 is a block diagram of a thin film type force detection probe for a scanning force microscope as a fifth embodiment, and FIG. 11 is a block diagram of a scanning force microscope using the same.

As shown in FIGS. 1 and 2, the thin-film force detection probe for a scanning force microscope as the first embodiment has a tip 1a at the tip and the other end supported by a silicon wafer 4. Thin-film elastic body 1 serving as a thin film, and a layer structure 2 in which electrode 2a, second thin-film 2b, and electrode 2c are mounted on the thin-film elastic body 1 in this order
And a capacitance detector 3 connected to the electrodes 2a and 2c of the same layer structure 2 for converting the electric capacitance between the electrodes 2a and 2c of the second thin film 2b into a voltage signal for detection. . The second thin film 2b is formed as a thin film that changes the electric capacitance between the electrodes 2a and 2c according to the bending stress received by the thin film 2b. For example, the second thin film 2b is a zinc oxide thin film formed by a high frequency magnetron sputtering method in a strong magnetic field (hence high plasma density). When this zinc oxide thin film is used as the second thin film, the change in stress applied to the thin film elastic body 1 (layer structure 2) due to the repulsive force between the tip 1a and the sample surface and the change in electric capacitance between the electrodes 2a and 2c. It has been empirically known that the relationship of is as shown in FIG.

The capacitance detector 3 is composed of a signal generator 3a for outputting a voltage signal of a required frequency and amplitude and a charge detector 3b for converting a charge signal into a voltage signal at a constant conversion ratio. One electrode 2a (or 2c) is connected to the signal generator 3a, and the other electrode 2c (or 2a) is connected to the charge detector 3b. As a result, the electric capacitance between the electrodes 2a and 2c is replaced with the charge signal by the constant voltage signal from the signal generator, and the charge signal is converted into the voltage signal by the charge amplifier 3b. The material (first thin film) of the thin film elastic body 1 is formed of a silicon oxide film or a nitride film. The tip 1a is formed of a silicon oxide film or a nitride film of the same material as the thin film elastic body 1 by utilizing silicon etching or the like, or the tip is sharpened by a scanning tunneling microscope (STM). It is formed by joining a tungsten tip for use, a special whisker, or the like to the tip of the probe 1.

The shape of the thin film elastic body 1 is shown in FIG.
The rectangular type shown in Fig. 2 and the triangular type shown in Fig. 2 (b) can be considered. In general, the triangular type has a more stable structure, and thus a signal corresponding to the electric capacitance of the second thin film 2b of the layer structure 2 is obtained. Is expected to stabilize. Thin-film elastic body 1 described above
And materials for various structures of the cantilever consisting of the layer structure 2,
An example of specifications is shown in [Table 1].

[Table 1] The cantilever composed of the thin film elastic body 1 and the layer structure 2 is manufactured by using a microfabrication technique called micromachining such as anisotropic etching of silicon, reactive ion beam etching, and high frequency magnetron sputtering.

Next, the operation and effect when the thin-film force detection probe for a scanning force microscope of the first embodiment is used in a scanning force microscope will be described with reference to FIG. As shown in FIG. 3, the scanning force microscope can be configured as follows. As a sample holder, the Z axis direction (vertical direction, normal to the sample surface) of the sample 15 is determined based on the Z axis coarse motion signal Z-CS output from the CPU 11 via the Z axis coarse motion unit 12a. A Z-axis coarse movement mechanism 10 for performing coarse movement is provided, and a cantilever composed of the thin film elastic body 1 and the layer structure 2 is arranged so as to face the sample 15 on the Z-axis coarse movement mechanism 10. .

The silicon wafer 4 supporting the cantilever is output from the CPU 11 via the base 16 via the power amplifiers 12b and 12c to the XY scan signal XY-F.
It is fixed to the XYZ piezoelectric scanning body 9 as a precision fine movement mechanism capable of finely moving in three dimensions based on the S, Z control signal Z-FS, whereby the three-dimensional relative movement between the cantilever and the sample 15 is achieved. The positional relationship can be changed. The XYZ piezoelectric scanning body 9 and the Z-axis coarse movement mechanism 10
3 are integrally fixed to the support base 14 in the example shown in FIG. 3 in consideration of stability against vibration disturbance, but each should be configured on an independent support base using a three-point support mechanism or the like. Is also possible. The output S1 of the capacitance detector 3 for converting the electric capacitance of the second thin film 2b into a voltage signal is the lock-in amplifier 8
To the input signal S2 to the CPU 11 and amplified. The reference signal REF necessary for the lock-in amplifier 8 is input from the signal generator 3a. Further, the CPU 11 has a display capable of displaying an image based on an input signal from the CPU 11.
13 are connected.

With the above arrangement, the scanning force microscope of this embodiment has the following effects. First, the sample 15 is brought closer to the tip 1a by the Z-axis coarse movement mechanism 10, and the tip 1a
Upon contact with the surface of 15, repulsive force acts on the chip 1a to deform the layer structure 2 together with the thin film elastic body 1, and the second thin film 2b corresponds to the repulsive force (corresponding to the deformation amount of the thin film elastic body 1).
Subject to bending stress. As a result, the electric capacitance between the electrodes 2a and 2c of the second thin film 2b decreases according to the characteristics as shown in FIG.
S1 and S2 will also decrease.

With the detection signal S1 from the capacitance detector 3 decreasing, that is, with the chip 1a receiving the repulsive force from the surface of the sample 15, the XY scanning signal XY- from the CPU 11 is detected.
The XYZ piezoelectric scanning body 9 is driven by the FS and the sample 15 is XY
When scanned in the direction, the chip
Since the repulsive force received by 1a, that is, the amount of deformation of the thin film elastic body 1, changes, the bending stress received by the second thin film 2b and the electrode 2a,
The electric capacitance between 2c also changes, and the detection signals S1 and S2 also change. In the measurement mode, which can be called a constant force (constant displacement) mode, while the sample 15 is being scanned by the XYZ piezoelectric scanning body 9 in the XY directions, the Z direction displacement of the XYZ piezoelectric scanning body 9 is performed by feedback control based on the detection signal S2. Is adjusted so that the repulsive force received by the chip 1a, that is, the amount of deformation of the thin film elastic body 1 is kept constant. Then, using the signal Z-FS from the CPU 11 applied to the XYZ piezoelectric scanning body 9, the unevenness on the surface of the sample 15 is imaged on the display 13.

As described above, according to the thin film type force detection probe for the scanning force microscope of this embodiment, the following effects and advantages can be obtained. First, since another displacement gauge such as an optical lever for measuring the AC displacement of the cantilever is not necessary, the device becomes compact and it is not necessary to perform complicated operations such as adjustment of the optical system. Further, the device configuration can be performed only by replacing the tunnel tip portion of the conventional STM (scanning tunneling microscope) with the cantilever including the thin film elastic body 1 and the layer structure 2 of this embodiment. Since the device is simple, it can be easily used for an experiment under a special environment in vacuum or low temperature.

Next, a thin film type force detection probe for a scanning force microscope as a second embodiment will be described with reference to FIGS. As shown in FIG. 5, the thin-film force detection probe for a scanning force microscope as the second embodiment has a tip 1a at the tip and the other end supported by a silicon wafer 4 as in the first embodiment. 1 thin film elastic body 1 and the same thin film elastic body 1
The electrode 2a, the second thin film 2b, and the electrode 2c are mounted in this order on the layer structure 2.

Then, the silicon wafer 4 is placed on a piezoelectric plate 5 as a piezoelectric body excitation mechanism. The piezoelectric plate 5 has an oscillator 7
The piezoelectric plate 5 is vibrated at a required amplitude and frequency by the modulation signal MS from the oscillator 7. Also, the layer structure 2
Electrodes 2a and 2c of the second thin film 2b
Detection in which the electric capacitance between a and 2c can be detected by converting it into a voltage signal, and the output charge from the second thin film can be converted into a voltage signal and detected by switching the connection by the switching means 6. A vessel 3'is provided.

The second thin film 2b is formed as a thin film that changes the electric capacitance between the electrodes 2a and 2c according to the bending stress received by the thin film 2b, and at the same time is a thin film having piezoelectricity. For example, the second thin film 2b is a zinc oxide thin film formed by a high-frequency magnetron sputtering method in a strong magnetic field (and thus a high plasma density). The zinc oxide thin film formed by the sputtering method is generally perpendicular to the substrate on which it is formed. Has a property that a specific orientation (C axis) of the crystal is oriented,
As a result, it has piezoelectricity. The change in capacitance due to stress (FIG. 4) and the piezoelectric effect when this zinc oxide thin film is used as the second thin film have already been confirmed in the device having the structure shown in FIG.

The detector 3'is composed of a signal generator 3'a for outputting a voltage signal of a required frequency and amplitude and a charge detector 3'b for converting a charge signal into a voltage signal at a constant conversion ratio. The one electrode 2a (or 2c) is connected to the signal generator 3a, and the other electrode 2c (or 2a) is connected to the charge detector 3b. Furthermore, the signal generator 3'a and the electrode 2a (or
A switching means 6 is provided between the switch 2 and 2c). First
Similar to the embodiment, when detecting a change in capacitance corresponding to a static displacement of the thin film elastic body 1 or a change in capacitance caused by a piezoelectric effect due to dynamic resonance, the switching means 6 is set to the 6a side. Is set. As a result, the electric capacitance between the electrodes 2a and 2c is replaced with a charge signal by the constant voltage signal from the signal generator 3'a, and the charge signal is converted into a voltage signal by the charge amplifier 3'b. On the other hand, when the electric charge generated by the piezoelectric effect is directly detected, the switching means is set to the 6b side, and the electric charge amplifier 3′b converts the generated electric charge into a voltage signal. The material (first thin film) of the thin film elastic body 1 and the chip 1a, the shape of the thin film elastic body 1 and the processing method are substantially the same as those in the first embodiment.

Next, the operation and effect when the thin-film force detection probe for a scanning force microscope of the second embodiment is used in a scanning force microscope will be described with reference to FIG. As shown in FIG. 6, the configuration of the scanning force microscope of this example is almost the same as that of the first example. That is, as a sample holding base, C
Z output from PU11 via Z-axis coarse movement unit 12a
A Z-axis coarse movement mechanism 10 for performing coarse movement of the sample 15 in the Z-axis direction (vertical direction, direction normal to the sample surface) based on the axis coarse movement signal Z-CS is provided. Samples on 10
A cantilever composed of the thin film elastic body 1 and the layer structure 2 is arranged so as to be opposed to 15. Then, the silicon wafer 4 supporting the cantilever is a transmitter 7
C through the piezoelectric plate 5 and the base 16 that can be vibrated by
XY output from PU11 via power amplifiers 12b and 12c
It is fixed to the XYZ piezoelectric scanning body 9 as a precision fine movement mechanism capable of finely moving in three dimensions based on the scanning signals XY-FS and Z control signal Z-FS. The relative positional relationship of can be changed.

Although the XYZ piezoelectric scanning body 9 and the Z-axis coarse movement mechanism 10 are integrally fixed to the support base 14 in the example shown in FIG. 6 in consideration of stability against vibration disturbance, they are supported at three points. It is also possible to construct each on an independent support base using a mechanism or the like. When the switching means 6 is set to the 6a side and the signal corresponding to the electric capacity of the second thin film 2b is used as the scanning control signal, the second thin film 2b The output S1 of the detector 3'which converts the electric capacitance into a voltage signal is input to the lock-in amplifier 8 and amplified to the input signal S2 to the CPU 11. The reference signal REF required for the lock-in amplifier 8 is provided by the switching means 17a.
It is set to the side and is input from the signal generator 3a.

On the other hand, the switching means 6 is set to the 6b side, and the cantilever composed of the thin film elastic body 1 and the layer structure 2 is excited by the piezoelectric plate 5 to generate a signal corresponding to the electric charge generated from the second thin film 2b. When used as a scanning control signal, the output S1 from the detector 3 ', that is, the charge detector 3'b
Is input to the lock-in amplifier 8 and the input signal to the CPU 11
It is amplified to S2. The reference signal REF necessary for the lock-in amplifier 8 is input from the oscillator 7 with the switching means 17 set to the 17b side. Further, the CPU 11 has a display 13 capable of displaying an image based on an input signal from the CPU 11.
Are connected.

With the above arrangement, the scanning force microscope of this example has the following effects. Generally, a scanning force microscope has a contact type that detects the force in the repulsive force region, a periodic contact type that uses the reduction of the vibration amplitude due to the collision of the vibrating cantilever with the sample surface, and a cantilever that vibrates in the non-contact force region. It can be classified into three types of non-contact type that utilizes the phenomenon of changing its natural frequency depending on the gradient of. First, if the switching means 6 is set to the 6a side and the modulation signal MS for causing the cantilever composed of the thin film elastic body 1 and the layer structure 2 to resonate is not transmitted from the oscillator 7, the scanning force microscope of the present example is also the first. The same effect as that of the scanning force microscope according to the embodiment can be obtained. That is, the Z-axis coarse movement mechanism 10
To bring sample 15 close to tip 1a, and tip 1a
When it comes into contact with the surface of, the repulsive force acts on the chip 1a to deform the layer structure 2 together with the thin film elastic body 1, and the second thin film 2b bends corresponding to the repulsive force (corresponding to the deformation amount of the thin film elastic body 1). Receive stress. As a result, according to the characteristics as shown in FIG. 4, the electric capacitance between the electrodes 2a and 2c of the second thin film 2b decreases, and the signal S is smaller than that when the chip 1a is not receiving the force.
1, S2 will also decrease.

With the detection signal S1 from the capacitance detector 3 decreasing, that is, with the chip 1a receiving the repulsive force from the surface of the sample 15, the XY scanning signal XY- from the CPU 11 is obtained.
The XYZ piezoelectric scanning body 9 is driven by the FS and the sample 15 is XY
When scanned in the direction, the chip
Since the repulsive force received by 1a, that is, the amount of deformation of the thin film elastic body 1, changes, the bending stress received by the second thin film 2b and the electrode 2a,
The electric capacitance between 2c also changes, and the detection signals S1 and S2 also change. In the measurement mode, which can be called a constant force (constant displacement) mode, while the sample 15 is being scanned by the XYZ piezoelectric scanning body 9 in the XY directions, the Z direction displacement of the XYZ piezoelectric scanning body 9 is performed by feedback control based on the detection signal S2. Is adjusted so that the repulsive force received by the chip 1a, that is, the amount of deformation of the thin film elastic body 1 is kept constant. Then, using the signal Z-FS from the CPU 11 applied to the XYZ piezoelectric scanning body 9, the unevenness on the surface of the sample 15 is imaged on the display 13.

Next, when the modulation signal MS from the oscillator 7 is sent to the piezoelectric plate 5 and the cantilever is vibrated, it functions as a periodic contact type or non-contact type scanning force microscope. . In order to function as the periodic contact type, the vibration energy of the cantilever composed of the thin film elastic body 1 and the layer structure 2 needs to be sufficiently large. Particularly in the atmosphere, since the chip 1a is easily captured by the contaminated layer on the surface of the sample 15, the cantilever must have a rigidity of 10 N / m or more and a vibration amplitude of several tens of nm. In the periodic contact type, first, the sample 15 is brought close to the tip 1a vibrating at the resonance point of the cantilever by the Z-axis coarse movement mechanism 10,
When 1a periodically contacts the surface of sample 15, tip 1a
The vibration amplitude of is limited by the surface of the sample 15. As a result, the amplitude of the cantilever is reduced as compared with the vibration amplitude in the unconstrained state. Switching means 6
Is set to the 6a side, by utilizing the fact that the second thin film 2b changes its electric capacity due to piezoelectricity according to the vibration amplitude of the cantilever, a signal corresponding to the electric capacity is used as a scanning control signal. To use.

When the switching means 6 is set to the 6b side, the signal S1 from the detector 3'becomes a signal corresponding to the electric charge generated by the piezoelectric effect. Since the generated charge almost faithfully reflects the vibration state of the cantilever, it is suitable as a scanning control signal for a vibration type scanning force microscope. In this case, the vibration amplitude of the tip 1a and the cantilever changes according to the distance between the neutral position of the tip 1a and the surface of the sample 15, and as a result, the charge generated from the second thin film 2b changes and the detection signal S1 and S2 also change. In the state where the detection signal S1 from the detector 3 ′ is decreasing, that is, in the state where the chip 1a periodically collides with the surface of the sample 15,
When the XYZ piezoelectric scanning body 9 is driven by the XY scanning signal XY-FS from the CPU 11 to scan the sample 15 in the XY directions,
Since the vibration amplitude of the chip 1a changes according to the unevenness of the surface of the sample 15, the piezoelectric charges generated between the second thin films 2b also change, and the detection signals S1 and S2 also change.

In the measurement mode, which can be called a constant force (constant displacement) mode, the sample 15 is moved by the XYZ piezoelectric scanning body 9 in the X direction.
While scanning in the Y direction, the Z direction displacement of the XYZ piezoelectric scanning body 9 is adjusted by feedback control based on the detection signal S2, so that the vibration amplitude of the chip 1a, that is, the generated charge is kept constant. Then, the CP applied to the XYZ piezoelectric scanning body 9
The surface roughness of the sample 15 is imaged on the display 13 using the signal Z-FS from U11. Further, in order to function as a non-contact type, the thin film elastic body 1 and the layer structure 2 are
The vibration amplitude of the cantilever consisting of and is several nm or less, and the rigidity is suitable to be several N / m.

In the non-contact type, first, the sample 15 is brought close to the tip 1a vibrating at the resonance point of the cantilever by the Z-axis coarse movement mechanism 10, and the tip 1a starts to receive a force gradient from the surface of the sample 15, Since the natural frequency of the above cantilever moves (low frequency side in the case of attractive force, high frequency side in the case of repulsive force), the vibration amplitude of the chip 1a at the original resonated frequency decreases and the phase also changes. To do. As a result, the amplitude of the cantilever is reduced as compared with the vibration amplitude in the free vibration state without being restrained. When the switching means 6 is set to the 6a side, the second thin film 2b changes its electric capacity by piezoelectricity according to the vibration amplitude of the cantilever, and a signal corresponding to the electric capacity is scanned. Used as a control signal.

When the switching means 6 is set to the 6b side, the signal S1 from the detector 3'becomes a signal corresponding to the electric charge generated by the piezoelectric effect. Since the generated charge almost faithfully reflects the vibration state of the cantilever, it is suitable as a scanning control signal for a vibration type scanning force microscope. In this case, the gradient of the force acting changes according to the distance between the neutral position of the tip 1a and the surface of the sample 15, and the vibration amplitude of the tip 1a and the cantilever changes.
As a result, the charge generated from the second thin film 2b changes, and the detection signals S1 and S2 also change.

With the detection signal S1 from the detector 3'decreasing, that is, with the tip 1a being subjected to the force gradient from the surface of the sample 15, the XY scanning signal XY-FS from the CPU 11 is used. Sample 1 by driving the XYZ piezoelectric scanning body 9
When 5 is scanned in the XY directions, the vibration amplitude of the chip 1a changes according to the unevenness of the surface of the sample 15, so the amplitude and phase of the piezoelectric charges generated between the second thin films 2b also change, and the detection signal
That of S1 and S2 also changes. In the measurement mode that can be called constant force (constant displacement) mode, the sample 15 is XYZ
While scanning in the XY directions by the piezoelectric scanning body 9, the XYZ piezoelectric scanning body 9 is controlled by feedback based on the detection signal S2.
By adjusting the displacement in the Z direction, the vibration amplitude of the chip 1a, that is, the amplitude or phase of the generated charges is kept constant. And
Signal Z from CPU 11 applied to XYZ piezoelectric scanning body 9
-Using FS, the unevenness of the surface of the sample 15 is displayed 13
Is imaged in.

As described above, according to the thin-film force detection probe for the scanning force microscope of this embodiment, the following effects and advantages can be obtained. First, since another displacement gauge such as an optical lever for measuring the AC displacement of the cantilever is not necessary, the device becomes compact and it is not necessary to perform complicated operations such as adjustment of the optical system. Further, the device configuration can be performed only by replacing the tunnel tip portion of the conventional STM (scanning tunneling microscope) with the cantilever including the thin film elastic body 1 and the layer structure 2 of this embodiment. Since the device is simple, it can be easily used for an experiment under a special environment in vacuum or low temperature. Furthermore, the thin-film force detection probe for the scanning force microscope is compatible with all three types of scanning force microscopes, and thus is very effective as an analyzer for various surfaces.

Next, a third embodiment of the present invention will be described with reference to FIG. Also in this embodiment, the basic overall configuration is the first
The configuration is almost the same as that of the embodiment (FIG. 1). In this embodiment, as shown in FIG. 7, the layer structure 2 is formed so as to be divided into two equal parts in the width direction of the thin film elastic body 1 as the first thin film. Therefore, in the figure, on the left side of the thin film elastic body 1, a layered structure 21 in which the electrode 21a, the second thin film, and the electrode 21c are layered in this order
And a layered structure 22 in which the electrode 22a, the second thin film, and the electrode 22c are layered in this order on the right side. The materials and the like of these layer structures 21 and 22 are the same as those in the first or second embodiment. Further, in this embodiment, two detectors 3'are provided. That is, the electric capacitance between the electrodes 21a and 21c or the piezoelectric charge generated therebetween and the electrodes 22a and 2c
The capacitance between 2c and the piezoelectric charge generated between them are detected by different detectors 3 ', and C
It will be input to PU11. The structure of each amplifier 3'is similar to that of the second embodiment.

The electrode 21a and the electrode 22a may be integrally formed, and this electrode may be the electrode connected to the signal generator 3a side of the detector 3 '. Since the thin-film force detection probe for a scanning force microscope of the third embodiment has the above-mentioned configuration, the following action can be obtained when used in a scanning force microscope. First, when operating as a contact-type scanning force microscope, the scanning direction is set to the thin film elastic body 1.
When it is made parallel to the width direction of, the displacement of the thin film elastic body 1 is affected by the unevenness of the sample and at the same time is affected by the frictional force. Since the thin film elastic body 1 is twisted by the frictional force, a difference occurs in the bending stress applied to the left and right layer structures 21 and 22.

Since the difference in the bending stress received by the layer structures 21 and 22 appears as the difference in the electric capacitance of the second thin film, the piezoelectric scanning body is arranged so that the difference between the detection signals from the detector 3'is constant. If the movement of 9 is controlled, an image of the surface of the sample can be obtained as an image of a constant lateral force. A scanning force microscope that utilizes such lateral force is called a horizontal force microscope (lateral force microscope, LFM). Even in a dynamic scanning force microscope such as a periodic contact type or a non-contact type, the cantilever including the tip 1a, that is, the thin film elastic body 1 is excited to receive the interaction between the tip 1a and the sample 15. In the area, when the tip 1a is scanned in the width direction of the cantilever, the tip 1a is subjected to the action of a vertical force gradient, and at the same time, the action of a lateral force corresponding to the frictional force is also exerted. receive. This lateral force is also a function of the distance between the surfaces of the cantilever samples, which affects the torsional vibration of the cantilever.

Since the torsional vibration of the cantilever appears as a difference between the piezoelectric charge signals (in some cases, signals corresponding to electric capacitance) from the second thin films of the left and right layered structures 21, 22, this difference is caused. If the movement of the piezoelectric scanning body 9 is controlled so that the force becomes constant, an image of the sample surface can be obtained as a constant image of the action of the lateral force. A type of LFM is constructed similar to the contact type. The image obtained by the above means is expected to be different from the uneven image showing the shape of the sample surface, and is expected to be an effective means for examining the physical properties of the surface. Of course, in this embodiment, 2
When the sum of the signals from the one detector 3'is used as the control signal, the same operation as in the second embodiment can be obtained.

Further, a thin film type force detection probe for a scanning force microscope as a fourth embodiment shown in FIG. 8 has a thin insulating film on the outermost side of the layer structure 2 (21, 22) in the first to third embodiments.
The feature is that 23 is formed. In this embodiment, the same effects as those of the above-described first to third embodiments can be obtained, and the following effects and advantages can be obtained. (1) It becomes a protective film during the manufacturing process. (2) It serves as a film that protects the second thin film 2b from moisture in the atmosphere. (3) The destruction of the layer structure 2 due to thermal stress is suppressed. Further, the detectors 3 and 3'in the first to fourth examples.
Can be formed in the vicinity of the layer structure 2 of the silicon wafer 4 by utilizing a semiconductor process.

Next, a thin film type force detection probe for a scanning force microscope as a fifth embodiment will be described with reference to FIGS. As shown in FIG. 10, the thin-film force detection probe for the scanning force microscope as the fifth embodiment has the tip 1a at the tip and the silicon wafer 4 at the other end as in the first and second embodiments.
The thin film elastic body 1 is composed of the first thin film supported by the thin film elastic body 1, and the layer structure 2 in which the electrode 2a, the second thin film 2b, and the electrode 2c are mounted on the thin film elastic body 1 in this order. And silicon wafer 4
Is placed on the piezoelectric plate 5 as a piezoelectric excitation mechanism. An oscillator 7 is connected to the piezoelectric plate 5, and the piezoelectric plate 5 is vibrated at a required amplitude and frequency by the modulation signal MS from the oscillator 7. Further, it is connected to the electrodes 2a and 2c of the layered structure 2 so that the change in the electric resistance between the electrodes 2a and 2c of the second thin film 2b can be converted into a change in the voltage signal and detected, and the switching means 6 '
The detector 40 is provided which can detect the output charge from the second thin film 2b by converting it into a voltage signal by switching the connection.

The second thin film 2b is formed as a thin film that changes the electrical resistance between the electrodes 2a and 2c according to the bending stress received by the thin film 2b, and at the same time is a thin film having piezoelectricity. For example, the second thin film 2b is a zinc oxide thin film formed by a high-frequency magnetron sputtering method in a strong magnetic field (and thus a high plasma density). The zinc oxide thin film formed by the sputtering method is generally perpendicular to the substrate on which it is formed. Has a property that a specific orientation (C axis) of the crystal is oriented,
As a result, it has piezoelectricity. When this zinc oxide thin film is used as the second thin film 2b, not only piezoelectricity but also a slight change in electric resistance due to stress is measured. Detector 40
Includes a signal generator 41 that outputs a voltage signal having a required frequency and amplitude, and a charge amplifier 42 that converts the charge signal into a voltage signal at a constant conversion ratio. The charge amplifier 42 includes a field effect transistor (FET) 42a on the input terminal side, and an input signal is guided to the gate of the FET 42a.
A negative bias voltage is applied to this gate via a negative feedback resistor R. In normal operation, the input charge is guided to the negative feedback capacitance C and converted into a voltage signal at a conversion ratio determined by the value of the negative feedback capacitance C.

Further, one electrode 2a (or 2c) is connected to the signal generator 41 via the switching means 6 ', and the other electrode 2c (or 2a) is connected to the charge amplifier 42 via the switching means 46. It is supposed to be connected. When detecting a change in electric resistance corresponding to a static displacement of the thin film elastic body 1 or a change in electric resistance due to dynamic resonance, the switching means 6'is set to the 6'a side and the switching means 46 '. Is set on the 46a side. As a result, a charge signal corresponding to the magnitude of the electric capacitance between the electrodes 2a and 2c and the magnitude of the voltage signal from the signal generator 41 is input to the charge amplifier 42.
When the electric resistance of the second thin film 2b (which is considered to exist in parallel with the electric capacity) is sufficiently larger than the negative feedback resistance R, the bias voltage applied to the gate of the FET 42a is set. Since the current is kept at a value, the current flowing into the gate is very small, and the above charge signal is almost entirely charged in the negative feedback capacitance C. On the other hand, when the electric resistance of the second thin film 2b decreases and becomes equal to or less than the negative feedback resistance R, the above bias voltage becomes smaller than the set value, so that the charge signal The amount that flows into the negative feedback capacitance C of is reduced. Therefore, as a result, a change in the electric resistance of the second thin film 2b appears as a change in the output signal of the charge amplifier 42, and the detector 40 functions as a resistance detector.

On the other hand, in the case of directly detecting the electric charge generated by the piezoelectric effect, the switching means 6'is set to the 6'b side and the switching means 46 is set to the 46b side so that the generated electric charge is stored in the capacitor Ci. Through the charge amplifier 42, the voltage signal is converted into a voltage signal, so that the detector 40 functions as a charge detector. The material of the thin film elastic body 1 and the chip 1a (first thin film), the shape of the thin film elastic body 1 and the processing method are
It is almost the same as the embodiment. Next, the operation and effect when the thin-film force detection probe for a scanning force microscope of the fifth embodiment is used in a scanning force microscope will be described with reference to FIG. Figure
As shown in FIG. 11, the configuration of the scanning force microscope of this example is
This is almost the same as that of the second embodiment. That is, the sample 15 is used as a sample holder based on the Z-axis coarse movement signal Z-CS output from the CPU 11 via the Z-axis coarse movement unit 12a.
Is provided with a Z-axis coarse movement mechanism 10 for performing coarse movement in the Z-axis direction (vertical direction, direction normal to the sample surface), and is arranged so as to face the sample 15 on the Z-axis coarse movement mechanism 10. A cantilever including a thin film elastic body 1 and a layer structure 2 is arranged.

The silicon wafer 4 supporting the cantilever is a piezoelectric plate 5 which can be vibrated by the oscillator 7.
And the power amplifier 12b, 1 from the CPU 11 via the base 16.
It is fixed to the XYZ piezoelectric scanning body 9 as a precision fine movement mechanism capable of finely moving in three dimensions on the basis of the XY scanning signal XY-FS and the Z control signal Z-FS output via 2c. The three-dimensional relative positional relationship between the samples 15 can be changed. In addition,
Although the XYZ piezoelectric scanning body 9 and the Z-axis coarse movement mechanism 10 are integrally fixed to the support base 14 in the example shown in FIG. 11 in consideration of the stability against vibration disturbance, a three-point support mechanism or the like is used. It is also possible to construct each on an independent support base. When the switching means 6 ′ is set to the 6a side and the switching means 46 is set to the 46a side and the signal corresponding to the change in the electric resistance of the second thin film 2b is used as the scanning control signal, The output S1 of the detector 40, which converts the electric resistance of the thin film 2b into a voltage signal, is input to the lock-in amplifier 8 and amplified into an input signal S2 to the CPU 11. The reference signal REF required for the lock-in amplifier 8 is provided by the switching means 17a.
It is set to the side and input from the signal generator 41.

On the other hand, the switching means 6'is set to the 6'b side, the switching means 46 is set to the 46b side, and the cantilever composed of the thin film elastic body 1 and the layer structure 2 is excited by the piezoelectric plate 5. , When a signal corresponding to the charges generated from the second thin film 2b is used as the scan control signal,
The output S1 from the detector 40, that is, the charge detector 42 is input to the lock-in amplifier 8 and amplified to the input signal S2 to the CPU 11. The reference signal REF necessary for the lock-in amplifier 8
Is input from the transmitter 7 with the switching means 17 set to the 17b side. A display 13 capable of displaying an image based on an input signal from the CPU 11 is connected to the CPU 11.

With the above arrangement, the scanning force microscope of this example has the following operational effects. First, if the switching means 6'is set to the 6'a side (the switching means 46 is 46a) and the oscillator 7 does not send out the modulation signal MS that causes the cantilever composed of the thin film elastic body 1 and the layer structure 2 to resonate, feedback is performed. The scanning force microscope of this example is also the first except that a signal corresponding to a change in electric resistance is used as the signal.
The same effect as that of the scanning force microscope according to the embodiment can be obtained. That is, the sample is moved by the Z-axis coarse movement mechanism 10.
When 15 is brought close to the tip 1a and the tip 1a comes into contact with the surface of the sample 15, a repulsive force acts on the tip 1a to deform the layer structure 2 together with the thin film elastic body 1 and the second thin film 2b corresponds to the repulsive force ( It receives a bending stress (corresponding to the amount of deformation of the thin film elastic body 1). As a result, the electric resistance between the electrodes 2a and 2c of the second thin film 2b is reduced, and the signals S1 and S2 are also reduced as compared with the state in which the chip 1a is not receiving the force.

With the detection signal S1 from the detector 40 decreasing, that is, with the chip 1a receiving the repulsive force from the surface of the sample 15, the XY scanning signal XY-FS from the CPU 11 is obtained.
When the XYZ piezoelectric scanning body 9 is driven to scan the sample 15 in the XY directions, the repulsive force received by the chip 1a, that is, the amount of deformation of the thin film elastic body 1 changes according to the unevenness of the surface of the sample 15, so that the second thin film The bending stress received by 2b and the electrical resistance between the electrodes 2a and 2c also change, and the detection signals S1 and S2 also change.
In the measurement mode, which can be called a constant force (constant displacement) mode, while the sample 15 is being scanned by the XYZ piezoelectric scanning body 9 in the XY directions, the Z direction displacement of the XYZ piezoelectric scanning body 9 is performed by feedback control based on the detection signal S2. Adjust the tip
The repulsive force received by 1a, that is, the amount of deformation of the thin film elastic body 1 is kept constant. Then, the C applied to the XYZ piezoelectric scanning body 9
The unevenness of the surface of the sample 15 is imaged on the display 13 using the signal Z-FS from PU11.

Next, when the modulation signal MS from the oscillator 7 is sent to the piezoelectric plate 5 and the cantilever is vibrated, as in the second embodiment, the periodic contact type or non-contact type scanning type is used. It will function as a force microscope. In order to function as the periodic contact type, the vibration energy of the cantilever composed of the thin film elastic body 1 and the layer structure 2 needs to be sufficiently large. Particularly in the atmosphere, since the chip 1a is easily captured by the contaminated layer on the surface of the sample 15, the cantilever must have a rigidity of 10 N / m or more and a vibration amplitude of several tens of nm. In the periodic contact type, first, the sample 15 is brought close to the tip 1a vibrating at the resonance point of the cantilever by the Z-axis coarse movement mechanism 10 and the tip 1a starts contacting the surface of the sample 15 periodically. The vibration amplitude of is limited by the surface of the sample 15. As a result, the amplitude of the cantilever is reduced as compared with the vibration amplitude in the unconstrained state.

The switching means 6'is on the 6'b side (switching means 46
Is set to the 46b side), the signal S1 from the detector 40 becomes a signal corresponding to the electric charge generated by the piezoelectric effect. Since the generated charge almost faithfully reflects the vibration state of the cantilever, it is suitable as a scanning control signal for a vibration type scanning force microscope. In this case chip 1a
The vibration amplitude of the tip 1a and the cantilever changes according to the distance between the neutral position of the sample 15 and the surface of the sample 15, and as a result, the electric charge generated from the second thin film 2b changes and the detection signal
S1 and S2 also change. With the detection signal S1 from the detector 40 decreasing, that is, with the chip 1a periodically colliding with the surface of the sample 15, the XY scanning signal X from the CPU 11 is detected.
When the XYZ piezoelectric scanning body 9 is driven by the Y-FS to scan the sample 15 in the XY directions, the vibration amplitude of the chip 1a changes according to the unevenness of the surface of the sample 15, so that the vibration occurs between the second thin films 2b. The piezoelectric charge also changes, and the detection signals S1 and S2 also change.

In the measurement mode, which can be called a constant force (constant displacement) mode, the sample 15 is moved by the XYZ piezoelectric scanning device 9 in the X direction.
While scanning in the Y direction, the Z direction displacement of the XYZ piezoelectric scanning body 9 is adjusted by feedback control based on the detection signal S2, so that the vibration amplitude of the chip 1a, that is, the generated charge is kept constant. Then, the CP applied to the XYZ piezoelectric scanning body 9
The surface roughness of the sample 15 is imaged on the display 13 using the signal Z-FS from U11. Further, in order to function as a non-contact type, the thin film elastic body 1 and the layer structure 2 are
The vibration amplitude of the cantilever consisting of and is several nm or less, and the rigidity is suitable to be several N / m. In the non-contact type, first, the sample 15 is brought closer to the tip 1a vibrating at the resonance point of the cantilever by the Z-axis coarse movement mechanism 10, and when the tip 1a starts to receive a force gradient from the surface of the sample 15, the cantilever Since the natural frequency moves (low frequency side in the case of attractive force, high frequency side in the case of repulsive force), the vibration amplitude of the chip 1a at the original resonated frequency decreases and the phase also changes. As a result, the amplitude of the cantilever is reduced as compared with the vibration amplitude in the free vibration state without being restrained.

The switching means 6'is on the 6'b side (switching means 46
Is set to the 46b side), the signal S1 from the detector 40 becomes a signal corresponding to the electric charge generated by the piezoelectric effect. The generated charge almost faithfully reflects the vibration state of the cantilever. In this case, the gradient of the force acting changes according to the distance between the neutral position of the tip 1a and the surface of the sample 15, and the vibration amplitude of the tip 1a and the cantilever changes. As a result, the charge generated from the second thin film 2b changes, and the detection signals S1 and S2 also change. When the detection signal S1 from the detector 40 is decreasing, that is, when the chip 1a is the sample 15
CPU under the action of force gradient from the surface of the CPU
When the XYZ piezoelectric scanning body 9 is driven by the XY scanning signal XY-FS from 11 to scan the sample 15 in the XY directions, the sample 15
Since the vibration amplitude of the chip 1a changes in accordance with the unevenness of the surface of, the amplitude and phase of the piezoelectric charges generated between the second thin films 2b also change, and the detection signals S1 and S2 also change.

In the measurement mode, which can be called a constant force (constant displacement) mode, the sample 15 is moved by the XYZ piezoelectric scanning device 9 in the X direction.
While scanning in the Y direction, the Z direction displacement of the XYZ piezoelectric scanning body 9 is adjusted by feedback control based on the detection signal S2, so that the vibration amplitude of the chip 1a, that is, the amplitude or phase of the generated charges is kept constant. Then, using the signal Z-FS from the CPU 11 applied to the XYZ piezoelectric scanning body 9, the unevenness on the surface of the sample 15 is imaged on the display 13. As described above, according to the thin-film force detection probe for a scanning force microscope of the present embodiment, the following effects and advantages can be obtained as in the first and second embodiments. First, since another displacement gauge such as an optical lever for measuring the AC displacement of the cantilever is not necessary, the device becomes compact and it is not necessary to perform complicated operations such as adjustment of the optical system. Further, the device configuration can be performed only by replacing the tunnel tip portion of the conventional STM (scanning tunneling microscope) with the cantilever including the thin film elastic body 1 and the layer structure 2 of this embodiment.

Since the apparatus is simple, it can be easily used for experiments in a special environment in vacuum or low temperature. Furthermore, the thin-film force detection probe for the scanning force microscope is compatible with all three types of scanning force microscopes, and thus is very effective as an analyzer for various surfaces. The basic configuration of this embodiment can be applied to the probe having the structure as in the third embodiment. The action and effect in that case are almost the same as those in the third embodiment. Also, the fourth
A protective film may be provided as in the embodiment, and the function and effect in this case are the same as those in the fourth embodiment. Furthermore, the charge amplifier 42 in the present embodiment can be built in the vicinity of the layer structure 2 of the silicon wafer 4 by utilizing a semiconductor process.

[0058]

As described in detail above, according to the thin film type force detection probe for a scanning force microscope of the present invention, the following effects and advantages can be obtained. (1) Since a separate displacement gauge such as an optical lever for measuring the displacement of the cantilever is unnecessary, the device becomes compact,
There is no need for complicated work such as adjustment between the cantilever portion and the optical system for converting the unevenness of the sample into the displacement. Especially when constructing a horizontal force microscope (LFM), the system is greatly simplified. (2) One probe can be used for any of the three types of scanning force microscopes (contact type, periodic contact type, non-contact type). (3) The device structure can be constructed by merely modifying the conventional STM (scanning tunneling microscope) tunnel tip portion to the cantilever of this embodiment. (4) Since the device is simplified, it can be easily used for experiments in a special environment in vacuum or low temperature. In particular, it is possible to easily construct an ultrahigh vacuum scanning force microscope in combination with the advantage of the above item (2).

[Brief description of drawings]

FIG. 1 is a configuration diagram of a thin-film force detection probe for a scanning force microscope as a first embodiment of the present invention.

FIG. 2 is a perspective view of a main part of the thin-film force detection probe for a scanning force microscope of FIG.

3 is a scanning force microscope using the thin film force detection probe for a scanning force microscope of FIG.

FIG. 4 is a characteristic diagram of the thin-film force detection probe for a scanning force microscope of FIG.

FIG. 5 is a configuration diagram of a thin-film force detection probe for a scanning force microscope as a second embodiment of the present invention.

6 is a scanning force microscope using the thin-film force detection probe for a scanning force microscope of FIG.

FIG. 7 is a plan view of a thin film type force detection probe for a scanning force microscope as a third embodiment of the present invention.

FIG. 8 is a configuration diagram of a thin-film force detection probe for a scanning force microscope as a fourth embodiment of the present invention.

FIG. 9 is a configuration diagram of a conventional scanning force microscope.

FIG. 10 is a configuration diagram of a thin-film force detection probe for a scanning force microscope as a fifth embodiment of the present invention.

11 is a configuration diagram of a scanning force microscope using the thin film force detection probe for a scanning force microscope of FIG.

[Explanation of symbols]

 1 Thin film elastic body as the first thin film 1a Chip 2 layer structure 2a electrode 2b 2nd thin film 2c electrode 21, 22 layer structure 21a, 22a electrode 21c, 22c electrode 3 capacitance detector 3'detector 3a, 3'a Signal generator 3b, 3'b Charge detector 4 Silicon wafer 5 Piezoelectric plate (Piezoelectric body excitation mechanism) 6 Switching means 6'Switching means 7 Transmitter 8 Lock-in amplifier 9 XYZ piezoelectric scanning body (precision movement mechanism) 10 Z-axis coarse movement mechanism (sample stand) 11 CPU 12a Z-axis coarse movement drive unit 12b Power amplifier 12c Power amplifier 13 Display 14 Support stand 15 Sample 16 Base stand 17 Switching means 23 Insulation film 40 Detector 41 Signal generator 42 Charge amplifier 42a FET 46 switching means

Claims (17)

[Claims] 1. A thin film elastic body made of a first thin film having a tip at its tip, an electrode, a second thin film elastic body, and a second thin film elastic body which are attached as a force detection system of a scanning force microscope to obtain information about the force on the sample surface. Thin film and at least three layers of electrodes mounted in this order, and a capacitance detector for converting the electric capacitance between the electrodes of the layer structure into a voltage signal for detection, and the second thin film is the same thin film. A thin-film force detection probe for a scanning force microscope, which is formed as a thin film that changes the electric capacitance between the electrodes according to the bending stress received by the electrode. 2. The thin-film force detection probe for a scanning force microscope according to claim 1, wherein the second thin film is formed as a thin film having piezoelectricity. 3. A piezoelectric body excitation mechanism for externally exciting and vibrating the cantilever composed of the thin film elastic body and the layer structure at its natural frequency.
Alternatively, the thin-film force detection probe for a scanning force microscope according to item 2. 4. The capacitance detector has two systems so that the layered structure is formed so as to be divided into two equal parts in the width direction, and the electric capacitance of each of the divided second thin films can be independently detected. The thin-film force detection probe for a scanning force microscope according to any one of claims 1 to 3, further comprising: 5. A charge detector for converting the charge output from the second thin film having the layer structure into a voltage signal for detection, and the output signal from the second thin film for the charge detector and the capacitance detector. 4. The thin-film force detection probe for a scanning force microscope according to claim 2, further comprising switching means selectively connected to either one of the above. 6. The charge detector has two input sections so that the charge output of each of the divided second thin films can be independently detected, and the output signal from the second thin film is divided into two. 5. The thin-film force detection probe for a scanning force microscope according to claim 4, further comprising switching means selectively connected to either one of the charge detector and the capacitance detector in both systems. 7. A cantilever composed of the thin film elastic body and the layer structure has one end supported by a silicon wafer, and the capacitance detector is integrally formed on the silicon wafer. The thin-film force detection probe for a scanning force microscope according to any one of 1 to 6. 8. A thin film elastic body made of a first thin film having a tip at the tip, an electrode, a second thin film elastic body attached to the thin film elastic body to attach information as a force detection system of a scanning force microscope to obtain information on the force on the sample surface. And a resistance detector for converting a change in electric resistance between the electrodes of the layer structure into a voltage signal to detect the change, and the second thin film is provided. A thin-film force detection probe for a scanning force microscope, characterized in that the thin-film force detection probe is formed as a thin film that changes the electrical resistance between the electrodes according to the bending stress applied to the thin film. 9. The thin-film force detection probe for a scanning force microscope according to claim 8, wherein the second thin film is formed as a thin film having both piezoelectricity. 10. The scanning according to claim 8, further comprising a piezoelectric body excitation mechanism for externally exciting and vibrating the cantilever composed of the thin film elastic body and the layer structure at its natural frequency. Type force detection probe for scanning force microscope. 11. The resistance detector is formed so that the layer structure is divided into two equal parts in a width direction, and the resistance detector can independently detect a change in electric resistance of each of the divided second thin films. The thin-film force detection probe for a scanning force microscope according to any one of claims 8 to 10, wherein the thin-film force detection probe has two systems of input sections. 12. A charge detector for converting a charge output from the second thin film having the layer structure into a voltage signal and detecting the voltage signal,
10. A switching means for selectively connecting an output signal from the second thin film to either one of the charge detector and the resistance detector, wherein the switching means is provided.
0. A thin film type force detection probe for a scanning force microscope according to item 0. 13. The charge detector has two systems of input sections so that the charge output of each of the divided second thin films can be detected independently, and the output signal from the second thin film is divided into two. 12. The thin-film force detection probe for a scanning force microscope according to claim 11, further comprising switching means selectively connected to either one of the charge detector and the resistance detector in both systems. 14. A cantilever composed of the thin film elastic body and the layer structure is supported at one end by a silicon wafer, and the resistance detector is integrally formed on the silicon wafer. The thin-film force detection probe for a scanning force microscope according to any one of 8 to 13. 15. The thin-film type for a scanning force microscope according to claim 1, wherein the tip is formed of a fine projection having a sharpened tip. Force detection probe. 16. The method according to claim 1, wherein the first thin film is formed of a silicon oxide film or a nitride film, and the second thin film is formed of a zinc oxide thin film. A thin film type force detection probe for a scanning force microscope according to one item. 17. The thin insulating film is formed on the surface of the outermost electrode of the layer structure.
16. A thin-film force detection probe for a scanning force microscope according to any one of 16 to 16.