JP2003057162A - Vibration-type probe sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vibration-type probe sensor in which a sharpened fiber prove itself is used as a vibrator and whose attachment to another vibrating element such as a tuning fork or the like is not required. SOLUTION: The vibration-type probe sensor has the fiber probe 13 having a probe part 12 formed by sharpening the tip of an optical fiber 11 and a drive part 17 formed by laminating a lower electrode 14, an electrostrictive-material layer 15 such as PZT, ZnO or the like and an upper electrode 16 on the outer circumference in the base end part of the fiber probe 13, and by applying an AC driving voltage AC to the layer 15 via the lower electrode 14 and the upper electrode 16 at the drive part 17, the fiber probe 13 is vibrated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is based on bringing the tip of the probe portion of the fiber probe closer to the object to be measured while vibrating the fiber probe having the probe portion formed by sharpening the tip of the fiber. The present invention relates to a vibration probe sensor that obtains a measurement output as a change in vibration state.

[0002]

2. Description of the Related Art In recent years, a scanning probe microscope (SPM: Sca:
nningProbe Microscope) is used.

As this scanning probe microscope, a scanning tunneling microscope (STM: Scanning Tunneling) for obtaining an uneven image of a sample based on a tunnel current flowing between a probe and the sample is used.
Microscope) or an atomic force microscope (AFM) that obtains a topographical image of a sample based on the atomic force acting between the sample and a probe attached to the tip of a cantilever called a cantilever.
Microscope).

Generally, in an atomic force microscope, a cantilever is bent and vibrated. On the other hand, a probe-like sensor has been proposed in which a vertical oscillator is used to improve the detection sensitivity.

[0005]

The conventional sharpened fiber probe has to be used by being attached to another vibrating element such as a tuning fork in order to control the distance between the sample and the probe.

The object of the present invention was proposed in view of such conventional circumstances, and the sharpened fiber probe itself serves as a vibrator, which does not need to be attached to another vibrating element such as a tuning fork. It is to provide a probe sensor.

[0007]

According to the present invention, the tip of the probe portion of the fiber probe is brought closer to the object to be measured while vibrating the fiber probe having the probe portion formed by sharpening the tip of the fiber. A vibration-type probe sensor that obtains a measurement output as a change in a vibration state, which has a driving unit formed by laminating a lower electrode, an electrostrictive material layer, and an upper electrode on the outer periphery of the base end of the fiber probe, The fiber probe vibrates when an AC drive voltage is applied to the electrostrictive material layer via the lower electrode and the upper electrode of the drive unit.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

A vibrating probe sensor according to the present invention has, for example, as shown in FIG. 1, a fiber probe 13 having a probe portion 12 formed by sharpening the tip of an optical fiber 11.
The lower electrode 14, the electrostrictive material layer 15 such as PZT or ZnO, and the upper electrode 1 are formed on the outer periphery of the base end portion of the fiber probe 13.
6 has a drive unit 17 formed by stacking 6 and the AC drive voltage AC is applied to the electrostrictive material layer 15 via the lower electrode 14 and the upper electrode 16 of the drive unit 17, whereby the fiber probe 13 is It has a structure that vibrates in the axial direction.

A vibration type probe sensor 1 having such a structure.
0 is produced by the following steps 1 to 4.

First, in step 1, as shown in FIG. 2A,
The tip of the optical fiber 11 is sharpened by a chemical etching method or the like to form a fiber probe 13 having a probe portion 12.

In the next step 2, gold Au is vapor-deposited while rotating the optical fiber 11 by means of a vacuum vapor deposition machine.
As shown in B, an Au film is uniformly formed on the outer periphery of the base end portion of the fiber probe 13 and is used as the lower electrode 14.

In the next step 3, the target 11 is sputtered or CVD or vacuum-deposited while rotating the fiber 11, so that the concentric circles of the fiber 11 are formed in the same manner as the gold of the lower electrode 14 as shown in FIG. 2C. Z
An nO film is formed and used as the electrostrictive material layer 15. This time,
The lower electrode 11 part is left on the surface.

In the next step 4, the Au film is formed on the ZnO film, that is, the electrostrictive material layer 15 by redepositing gold for the electrode in the same manner as the lower electrode 11 as shown in FIG. 2D. This is used as the upper electrode 16.

In this way, the vibration probe sensor 10
3A and 3C are a longitudinal sectional view and a lateral sectional view of FIG. This vibration type probe sensor 10 has a drive unit 17 having a structure symmetrical with respect to the axis of the optical fiber 11.

In this vibration type probe sensor 10, for example, as shown in FIG. 4, the fiber probe 13 having a probe portion 12 formed by sharpening the tip of an optical fiber 11 is vibrated in the axial direction. A probe 13 is used to obtain a measurement output as a change in the vibration state caused by bringing the tip of the probe portion 12 of 13 closer to the measurement object 1, and is used by being attached to the scanner 3 by the holding tool 2.

That is, this vibration type probe sensor 10
Since the driving unit 17 has a structure symmetrical with respect to the axis of the optical fiber 11, the driving unit 17 has an AC driving voltage applied to the electrostrictive material layer 15 via the lower electrode 14 and the upper electrode 16 of the driving unit 17. When AC is applied, the electrostrictive material layer 15 expands and contracts and the fiber probe 13 vibrates in the axial direction. When the tip of the probe portion 12 of the fiber probe 13 approaches the measurement object 1, the vibration is affected by the atomic force. Therefore, the change in the vibration state is detected to measure the shape of the measurement object 1. It can be performed.

The vibrating probe sensor 10 is
For example, by locally changing the thickness of the electrostrictive material layer 15 or the like, it is also possible to vibrate in the lateral direction with the drive unit 17 having a structure asymmetric with respect to the axis of the optical fiber 11.

Here, since the change in the vibration state due to the influence of the atomic force is also transmitted to the ZnO film, that is, the electrostrictive material layer 15, the complex transfer characteristic of the electrostrictive material layer 15 changes due to the influence. Therefore, as shown in FIG. 5, an ammeter 6 is installed in series with a power source 5 for applying an AC drive voltage AC to the electrostrictive material layer 15 via the lower electrode 14 and the upper electrode 16 of the drive unit 17. Thus, the change in the vibration state can be measured as a current value according to the change in the complex transfer characteristic of the electrostrictive material layer 15.

Further, in the vibration type probe sensor according to the present invention, the lower electrode, the electrostrictive material layer and the upper electrode are provided on the outer circumference of the base end portion of the fiber probe in order to detect the change in the vibration state due to the influence of the atomic force. You may make it provide the detection part comprised by laminating | stacking.

For example, a vibration type probe sensor 20 shown in FIG. 6 has a fiber probe 13 having a probe portion 12 formed by sharpening the tip of an optical fiber 11, and a lower electrode on the outer circumference of the base end portion of the fiber probe 13. 14, a drive unit 17 formed by laminating an electrostrictive material layer 15 such as PZT or ZnO and an upper electrode 16, a lower electrode 21 and an electrostrictive material layer such as PZT or ZnO on the outer periphery of the base end of the fiber probe 13. 22
And a detection unit 24 formed by laminating an upper electrode 23, and by applying an AC drive voltage AC to the electrostrictive material layer 15 via the lower electrode 14 and the upper electrode 16 of the drive unit 17, The fiber probe 13 vibrates in the axial direction, and the vibration of the fiber probe 13 in the axial direction is detected by the detection unit 24.
The voltage is converted into a voltage by the piezoelectric phenomenon in the electrostrictive material layer 22 and detected by the voltmeter 8.

Further, as in the vibration type probe sensor 30 shown in FIGS. 7A and 7B, the lower electrode 2 of the detection section 24 is used.
It is also possible to have a multilayer structure in which the No. 1, the electrostrictive material layer 22, and the upper electrode 23 are laminated on the outer periphery of the drive unit 17.

Here, the vibration probe sensor has a cantilever structure and has a natural vibration mode. Since the resonance state is detected by modulating with the frequency of the natural vibration mode, it is desirable that the frequency of the natural vibration mode can be adjusted.

As described above, in the vibration type probe sensor 10 attached to the scanner 3 by the holding tool 2 and used, the distance L from the holding tool 2 which is the fixed end to the tip of the vibration type probe sensor 10 is adjusted to be unique. The frequency of the vibration mode can be adjusted.

That is, when the sound velocity is v, the frequency of the lowest-order natural vibration mode is given by v / (4L). Therefore, by adjusting the distance L, the frequency of the natural vibration mode can be adjusted.

Further, the vibration type probe sensor 4 shown in FIG.
When the optical fiber 11 is gradually thinned as shown in 0, a natural vibration mode is generated in the thinned portion. In this case, since the length of the thinned portion can be adjusted by etching, the frequency reproducibility of the natural vibration mode can be improved. In this case, as shown in the longitudinal section of FIG. 9, if the electrostrictive material layers 15 and 22 are attached only to the thinned portions and the insulating material layers 31 and 32 are attached to the other portions, the thinned portions are unique. It is possible to detect the vibration mode with high accuracy. Further, in the vibration type probe sensor 40, the middle part is fixed by the holding tool 2, and the power source 5 is connected to the lower electrode 14 and the upper electrode 16 of the drive unit 17 on the rear end side of the fixed part, and the detection is performed. By connecting the voltmeter 8 to the lower electrode 21 and the upper electrode 23 of the portion 24, it is possible to prevent mechanical vibration from occurring at the connection portion.

Further, since the distance between the sample and the probe can be controlled in this way, and this vibrating probe sensor, since the core material is the optical fiber 11, the near field microscope in the state where the distance between the sample and the probe is controlled. The measurement can be performed.

[0028]

As described in detail above, in the vibration type probe sensor according to the present invention, the sharpened fiber probe is coated with an electrode and an electrostrictive material such as PZT or ZnO,
It is used to vibrate the sharpened fiber probe and it is used to detect the vibration of the sharpened fiber probe.

The conventional sharpened fiber probe is mounted on another vibrating element such as a tuning fork to control the distance between the sample and the probe. However, in the present invention, the sharpened fiber probe itself serves as a vibrator and the tuning fork or the like is used. It is not necessary to attach it to another vibrating element of the.

Further, in the vibration type probe sensor according to the present invention, since the sharpened fiber probe itself serves as a vibrator, stable, small size and high detection sensitivity can be expected.

In the vibration type probe sensor according to the present invention,
The resonance frequency is increased, and the control band for controlling the distance between the sample and the probe can be increased.

In the vibration type probe sensor according to the present invention, the sharpened fiber probe is extremely sharp and can be used as a general purpose surface shape measuring probe.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a structure of a vibration probe sensor according to the present invention.

FIG. 2 is a diagram showing a manufacturing process of the vibration probe sensor.

FIG. 3 is a vertical cross-sectional view and a horizontal cross-sectional view of the vibration probe sensor.

FIG. 4 is a diagram schematically showing a usage state of the vibration probe sensor.

FIG. 5 is a diagram showing a configuration in which a change in a vibration state due to an influence of an interatomic force in the vibration probe sensor is measured as a current value according to a change in a complex transfer characteristic of an electrostrictive material layer.

FIG. 6 is a diagram showing another example of the structure of the vibration probe sensor according to the present invention.

FIG. 7 is a diagram showing another example of the structure of the vibration probe sensor according to the present invention.

FIG. 8 is a diagram showing another example of the structure of the vibration probe sensor according to the present invention.

9 is a vertical cross-sectional view of the vibration probe sensor shown in FIG.

[Explanation of symbols]

1 object to be measured, 2 tools, 3 scanners, 5 power supplies,
6 ammeter, 8 voltmeter, 10 vibration type probe sensor, 11 optical fiber, 12 probe part, 13 fiber probe, 14 lower electrode, 15 electrostrictive material layer, 16
Upper electrode, 17 drive unit, 20 vibration type probe sensor,
21 lower electrode, 22 electrostrictive material layer, 23 upper electrode, 24
Detection unit, 30 vibration type probe sensor, 31, 32 insulating material layer, 40 vibration type probe sensor

Claims (4)

[Claims] 1. A vibration state change caused by bringing the tip of the probe portion of the fiber probe closer to the object to be measured while vibrating the fiber probe having the probe portion formed by sharpening the tip of the optical fiber. A vibrating probe sensor for obtaining a measurement output, which has a drive unit formed by laminating a lower electrode, an electrostrictive material layer, and an upper electrode on the outer periphery of the base end of the fiber probe, and a lower electrode of the drive unit. A vibrating probe sensor, wherein the fiber probe vibrates when an AC drive voltage is applied to the electrostrictive material layer via the upper electrode. 2. The vibration type probe sensor according to claim 1, wherein the change in the vibration state is detected as a change in the complex transfer characteristic of the electrostrictive material layer. 3. The vibration type probe sensor according to claim 1, further comprising a detection unit formed by laminating a lower electrode, an electrostrictive material layer, and an upper electrode on the outer periphery of the base end of the fiber probe. 4. The vibration type probe sensor according to claim 3, wherein the lower electrode, the electrostrictive material layer, and the upper electrode of the detection unit are laminated on the outer periphery of the drive unit.