JP2001059807A - Method and apparatus for processing probe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To selectively and safely break a lever desired to be broken. SOLUTION: An operator changes the frequency of the voltage signal generated by an oscillator 13 so that the amplitude of the sine wave displayed on an oscilloscope 12 becomes max. That is, the operator adjusts the oscillator 13 so that a lever 3a resonates, and the frequency of the voltage signal applied to a piezoelectric element 7 from the oscillator 13 becomes the intrinsic vibration frequency of the lever 3a. When the lever 3a resonates, the operator makes the amplitude of the voltage signal generated by the oscillator 13 large gradually while keeping the frequency of the voltage signal. Whereupon, the amplitude of the lever 3a becomes further large gradually and, when the bending of the lever 3a exceeds its elastic limit, the lever 3a is broken.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for processing a probe having a plurality of levers, and an apparatus for processing the probe.

[0002]

2. Description of the Related Art An atomic force microscope (AFM) included in a scanning probe microscope is designed so that an atomic force acting between a probe and a probe attached to a tip of a lever of a probe (cantilever) and a sample are constant. Alternatively, the sample or the probe is scanned while controlling the Z position of the probe, and an image of the sample surface shape is obtained from the result of the Z position control.

Further, a friction force microscope (FFM) included in a scanning probe microscope scans a sample in a lateral direction of the probe while a probe attached to the probe is in contact with the sample. The frictional force acting between the probe and the sample is measured from the lateral twist of the probe.

Further, the scanning probe microscope has a function of measuring various forces such as a magnetic force and an electrostatic force acting between a probe attached to the tip of the probe and the sample.

[0005] Some recent scanning probe microscopes have the above-mentioned AFM function, FFM function, and many other functions.

FIG. 1 shows a probe used in a scanning probe microscope having various functions as described above. A probe 1 has a plurality of pieces having different lengths on one side of a base material 2. The levers 3a, 3b and 3c are formed. In the figures, 4a, 4b, 4c are:
A probe fixed to the tip of the lever. By preparing such a probe having a plurality of levers, it is possible to select and use an optimal lever depending on the physical quantity to be measured and the sample without exchanging the probe during the sample observation.

[0007] Even when the state of the probe fixed to the tip of the lever used during the measurement has deteriorated, the lever can be changed and used without replacing the probe.

On the other hand, when the shortest lever 3b is used in the probe of FIG. 1, the sample is strongly pressed by the probes of the longer levers 3a and 3c. Therefore, depending on the sample, the surface is contaminated by the probe of the levers 3a and 3c, or the surface structure is destroyed.

Therefore, when it is determined that such a problem occurs, the operator performs an operation of folding an unnecessary lever using the tip of tweezers or the like before setting the probe in the apparatus.

[0010] Some recent scanning probe microscopes have both an AFM function and an STM function. At the time of STM observation, a bias voltage is applied to the sample, and the sample or the probe is controlled while the Z position of the sample or the probe is controlled such that the tunnel current flowing between the probe attached to the probe and the sample becomes constant. Are scanned, and an image of the sample surface shape is obtained from the result of the Z position control.

In such a scanning probe microscope, the probe shown in FIG. 1 is used. However, if the lever 3b is used for STM observation, the levers 3a and 3
The probe c contacts the sample. Therefore, lever 3
It becomes impossible to measure the tunnel current with the probe 4b fixed to the point b.

Therefore, even in such a case, the operator breaks an unnecessary lever using the tip of tweezers or the like before setting the probe in the apparatus.

[0013]

However, since the length of the lever is as short as about 100 to 300 μm and the interval between the levers is as short as about 100 to 300 μm, the operator mistakenly breaks another lever during the operation. Or was hurt.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a probe processing method and a probe processing apparatus capable of selectively and safely folding a lever to be folded. .

[0015]

Means for Solving the Problems A probe processing method of the present invention that achieves this object includes a probe having one end fixed and a plurality of levers at the other end, and a means for exciting the probe, The vibration means is controlled so that a lever to be folded out of the levers resonates, and the lever is folded. Further, the probe processing apparatus of the present invention includes a probe having one end fixed and a plurality of levers at the other end, means for detecting displacement of the lever and displaying the amplitude of the lever, an oscillator, and an oscillator; And means for vibrating the probe based on the output of (1).

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 shows an example of the probe processing apparatus of the present invention. In FIG. 2, components denoted by the same reference numerals as those in FIG. 1 indicate the same components.

In FIG. 2, the probe 1 shown in FIG. 1 is disposed in a processing chamber 5, and one end of the probe 1 is fixed to a probe support member 6 attached to a side wall of the processing chamber. In addition, a piezoelectric element 7 for vibration is attached near the fixed end of the probe 1.

The levers 3a, 3b, 3c of the probe 1
Is a reflection surface, and one of these surfaces is irradiated with laser light L from a laser light source 8. The laser light source 8 is fixed to a laser light source moving means 9 attached to the upper wall of the processing chamber, and the laser light source moving means 9 is movable in the xy directions.

The reflected light L 'reflected by the lever reaches the photodetector 10 and is detected. The photodetector 10 includes, for example, a four-division photodiode, and detects a change in the position of the reflected light L ′ in the z direction based on the vibration of the lever.

The detection signal obtained by the photodetector 10 is sent to an oscilloscope 12 via a preamplifier 11.

Reference numeral 13 denotes an oscillator. The oscillator 13 supplies a voltage signal of an arbitrary frequency to the piezoelectric element 7. The oscillator 13 and the piezoelectric element 7 constitute a probe vibration unit. The piezoelectric element 7 vibrates the probe based on the output of the oscillator 13.

Reference numeral 14 denotes an optical microscope provided on the upper wall of the processing chamber 5. Reference numeral 15 denotes an exhaust device, and the inside of the processing chamber 5 is exhausted to a high vacuum by the exhaust device 15.

The apparatus configuration shown in FIG. 2 has been described above. Hereinafter, a case in which such a processing apparatus is used to fold the levers 3a and 3c which hinder the use of the shortest lever 3b for sample observation will be described. I do.

First, while checking with the optical microscope 14, the operator adjusts the laser light source moving means 9 so that the laser light L strikes the lever 3a to be folded.

When the adjustment is completed, the operator operates the oscillator 13 so that a voltage signal of a certain frequency is supplied to the piezoelectric element 7 in order to start the oscillation of the lever 3a. By this operation, the piezoelectric element 7 vibrates at the frequency of the voltage signal from the oscillator 13, and the vibration is transmitted to each lever via the base material 2 of the probe. As a result, the vibration of the lever 3a starts, and the lever 3a vibrates at its natural frequency.

When the tip of the lever 3a moves up and down due to this vibration, the position of the reflected light L 'reaching the photodetector 10 changes, and a detection signal corresponding to the change in the position is output.
Obtained from Then, on the oscilloscope 12, the state of vibration of the lever 3a is displayed as a sine wave as shown in FIG. In FIG. 3, the horizontal axis represents time (t), and the vertical axis represents the position of the probe 4a in the z direction.

When the lever 3a starts oscillating in this manner, the operator then changes the frequency of the voltage signal generated by the oscillator 13 so that the amplitude of the sine wave displayed on the oscilloscope 12 is maximized. That is, the operator adjusts the frequency of the voltage signal applied from the oscillator 13 to the piezoelectric element 7 so that the lever 3a resonates.
The oscillator 13 is adjusted so that the natural frequency becomes.

When the lever 3a resonates by this adjustment,
While maintaining the frequency of the voltage signal generated by the oscillator 13, the operator increases the amplitude of the voltage signal. Then, the amplitude of the lever 3a gradually increases, and when the deflection of the lever 3a exceeds its elastic limit, the lever 3a
Breaks. At this time, the other levers 3b and 3c vibrate only at the natural frequency of the lever 3a but do not resonate, and their amplitudes are very small. Therefore, the lever 3a
The levers 3b and 3c remain firmly fixed to the base material 2 even if is broken.

Although the case where the lever 3a is folded has been described above, the operation of folding the lever 3c is performed in the same manner.

Thereafter, the laser light source 8 is attached to the remaining lever 3b.
, And a sample (not shown) arranged opposite to the probe 4b of the lever 3b is two-dimensionally scanned. Then, the output of the amplifier 11 at that time is sent to an image processing unit (not shown), and the image processing unit performs image processing, and an AFM image of the sample is displayed on a display unit (not shown).

In the probe processing apparatus shown in FIG. 2, since the lever is disposed in a vacuum, its Q value is large, and the lever is easily broken as compared with the atmosphere.

Next, another example of the probe processing apparatus of the present invention will be described with reference to FIG. In FIG. 4, components denoted by the same reference numerals as those in FIG. 2 indicate the same components.

The configuration of FIG. 4 differs from the configuration of FIG. 2 in that the oscillator is removed and the output signal of the preamplifier 11 is applied to the piezoelectric element 7 via the phase shifter 16, the waveform converter 17 and the amplitude adjusting circuit 18. That is to supply.

Hereinafter, a case will be described in which the levers 3a and 3c, which are obstacles when the shortest lever 3b is used for sample observation, are broken using such a processing apparatus.

First, while confirming with the optical microscope 14, the operator adjusts the laser light source moving means 9 so that the laser beam L strikes the lever 3a to be folded.

When the adjustment is completed, the operator operates the waveform converter 17 so that a square wave signal of a certain frequency is supplied to the piezoelectric element 7 via the amplitude adjustment circuit 18 in order to start the oscillation of the lever 3a. I do. By this operation, the piezoelectric element 7 vibrates at the frequency of the signal generated by the waveform converter 17, and the vibration is transmitted to each lever via the base material 2 of the probe. As a result, the vibration of the lever 3a starts, and the lever 3a vibrates at its natural frequency.

A detection signal from the photodetector 10 which has detected the vibration of the lever 3a is input to the phase shifter 16 via the preamplifier 11, and the output signal of the phase shifter 16 as shown in FIG. The signal is sent to the waveform converter 17. The waveform converter 17 is composed of, for example, a comparator and a Schmitt trigger circuit, and converts the sine wave signal of FIG.
The signal is converted into a square wave signal having a constant amplitude as shown in FIG.

This square wave signal is sent to the piezoelectric element 7 as a drive signal after its amplitude is adjusted by an amplitude adjusting circuit 18 composed of an attenuator or the like. The phase shifter 16 adjusts the phase of the oscillation signal so that the oscillation system operates with the maximum positive feedback. As a result, a positive feedback self-excited oscillation loop is formed, and the lever 3a resonates by the action of the positive feedback circuit and continues to vibrate at a predetermined amplitude.

Then, the operator operates the lever 3
In the state where “a” is in resonance, the output amplitude of the waveform converter 17 is increased. Then, the amplitude of the lever 3a gradually increases, and when the deflection of the lever 3a exceeds its elastic limit, the lever 3a breaks. At this time, the other levers 3b and 3
c is only vibrating at the natural frequency of the lever 3a and is not resonating, and its amplitude is very small. Therefore,
Even if the lever 3a breaks, the levers 3b and 3c remain firmly fixed to the base material 2.

Although the case where the lever 3a is folded has been described above, the operation of folding the lever 3c is performed in the same manner.

The positive feedback circuit in FIG. 4 utilizes the FM mode of the non-contact atomic force microscope, that is, the fact that when a force is applied to a lever oscillating at its natural frequency, the frequency of the lever shifts. This is used when measuring the shape of the sample surface. Therefore, in an atomic force microscope having such a positive feedback circuit, after the levers 3a and 3c are folded, the laser light from the laser light source 8 is applied to the remaining lever 3b, and the probe 4b of the lever 3b A sample (not shown) arranged opposite to is scanned two-dimensionally. Then, the output of the waveform converter 17 at that time is sent to an image processing means (not shown), and the image processing means displays an AFM image based on the shift of the frequency of the lever 3b on a display means (not shown). As described above, if the lever is selectively folded using an atomic force microscope provided with a positive feedback circuit, it is not necessary to newly provide a cantilever processing device separately from the atomic force microscope.

As shown in FIG. 6, even in a probe having a plurality of levers 19 to 21 having the same length, the natural frequencies are slightly different due to slight differences in shape and the like. As described above, since the Q value of the oscillation of the lever is large in a vacuum, even if the lever 19 is vibrated at its natural frequency in a vacuum, the other levers 20 and 21 do not resonate. Therefore, even in the probe as shown in FIG. 6, the target lever can be selectively folded using resonance.

Further, in the above description, the optical lever system is used for detecting the displacement of the probe, but other methods such as optical interference and a capacitance system may be used.

The present invention is applicable not only to the probe of the scanning probe microscope but also to the case where a lever having a plurality of levers used in another apparatus is selectively folded.

[Brief description of the drawings]

FIG. 1 shows a probe used in a scanning probe microscope.

FIG. 2 shows an example of a probe processing apparatus according to the present invention.

FIG. 3 shows a waveform displayed on an oscilloscope.

FIG. 4 shows another example of the probe processing apparatus of the present invention.

FIG. 5 is a view for explaining an operation of the probe processing apparatus shown in FIG. 4;

FIG. 6 shows a probe used in a scanning probe microscope.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Probe, 2 ... Base material, 3a, 3b, 3c ... Lever,
4a, 4b, 4c probe, 5 processing chamber, 6 probe support member, 7 piezoelectric element, 8 laser light source, 9 laser light source moving means, 10 photodetector, 11 preamplifier, 12
... oscilloscope, 13 ... oscillator, 14 ... optical microscope,
15: Exhaust device, 16: Phase shifter, 17: Waveform converter, 18: Amplitude adjustment circuit, 19, 20, 21 ... Lever

Claims (2)

[Claims] 1. A probe having one end fixed and a plurality of levers provided at the other end, and means for exciting the probe, wherein the exciting means is configured to resonate a lever to be folded among the levers. And the lever is folded to control the lever. 2. A probe having one end fixed and a plurality of levers at the other end, means for detecting displacement of the lever and displaying the amplitude of the lever, an oscillator, and an output from the oscillator. A probe processing apparatus comprising means for vibrating a probe.