JPH06109561A - Force detecting device - Google Patents

Abstract

PURPOSE:To eliminate the action of a force except an interatomic force among atoms and to enhance the accuracy of measurement by attaching an electric detection means to a cantilever or a joist. CONSTITUTION:A cantilever 20 is deformed by an electrostatic force between an electrostatic charge on a surface of a specimen and a probe 21. The deformation quantity is detected by means of a piezo resistance 22 of an electric detection means provided at a foot part A to be taken outside via patterns 23 so that a force applied to the probe 21 is measured. The cantilever 20 is made of an insulator material and the probe 21 and the resister 22 are electrically insulated from each other so that a voltage of the probe 21 is not influenced by the change of a voltage of the resister 22. Therefore, the action of an electrostatic force except a force among atoms is not generated between the surface of the specimen and the probe 21, thereby improving the accuracy of measurement.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a force detection device used in a scanning force microscope or a high resolution surface electrometer.

[0002]

2. Description of the Related Art As conventional force detecting devices, various devices applied to force microscopes have been proposed. For example, as the first conventional example, "ATOMIC FORCE MICROSC
"OPYUSING A PIEZORESISTIVE CANTILEVER", 199
1, some are disclosed in IEEE. this,
Now, description will be made with reference to FIGS. 20 and 21. In FIG. 20, a U-shaped cantilever 2 is fixed to one end of a pedestal 1. The pedestal 1 has a silicon oxide film 4 formed on the surface of the single crystal silicon 3, and the cantilever 2 has a piezoresistor 5 formed on the surface of the single crystal silicon 3. 5 are electrically connected by metal wiring 6.

In such a structure, since the entire cantilever 2 is a U-shaped resistor, the cantilever 2
Bending (strain) caused by the force applied to the tip of the piezoresistor 5 can be detected from the resistance value of the piezoresistor 5. FIG. 21 shows
It shows a state in which a Wheatstone bridge circuit is composed of the piezoresistor 5 and the fixed resistor 7, and the resistance change of the piezoresistor 5 can be detected from the change of the bridge voltage. Since the force applied to the tip of the cantilever 2 can be measured by using such a detection method, the atomic force can be measured and a microscopic image can be obtained.

As a second conventional example, "Charge sto
rage in a nitride-oxide-sillicon medium by scanning
capacitance microscopy ", 1991 ,. Appl.Phys.
Are disclosed in. This will now be described with reference to FIG. A sample 9 is placed on the piezoelectric element scanner 8. The piezoelectric element scanner 8 is drive-controlled by a controller 10. In addition, the sample 9
The tip of the cantilever 11 is attached to the upper part of the probe 12
Are in contact. The cantilever 11 is connected to the electric circuit 14 from the fixed end 13. On the other hand, a mirror 15 is attached to the upper surface of the probe 12, and the light from the laser light source 16 is incident on the mirror 15 and then reflected to receive a light receiving element (PSD) 17.
Is detected by and is sent to the controller 10 via the amplifier 18.

In such a structure, the cantilever 11 and the probe 12 are electrically conductive, and the fixed end 13 of the cantilever 11 is electrically connected to apply a predetermined voltage to the probe 12. To be done. Accordingly, the bending of the cantilever 11 can be detected by the “optical lever method” configured by the laser light source 16, the mirror 15 and the light receiving element 17, and the force applied to the probe 12 can be obtained. The electric charge or the surface potential existing on the surface of the can be measured.

[0006]

In the case of the first conventional example,
The tip of the cantilever 2 is a probe, and the entire cantilever 2 is piezoresistive. In this case, the change in the piezo resistance value can be obtained by the potential difference between the points a and b in the circuit as shown in FIG.
Therefore, if the resistance value of the piezoresistor 5 changes, the potential at the point a also changes, and accordingly, the potential of each part of the piezoresistor 5 also changes, which also changes the potential of the tip of the probe. become. Assuming that the potential of the sample surface is constant, the electrostatic attraction acting between the sample and the probe changes due to the potential fluctuation of the probe tip. A force called "electrostatic attraction of" acts, and as a result, the force becomes noise and the measurement accuracy decreases.

In the case of the second conventional example, since the bending of the cantilever 11 due to the electrostatic attraction generated between the surface charge of the sample 9 and the probe 12 is detected to measure the charge distribution, for example, a photosensitive sample is used. When observing the surface, the state of the sample surface changes due to scattered light of the laser light, and as a result, measurement and observation become impossible.

[0008]

According to the first aspect of the present invention, the bending caused by the force applied to the probe at the tip of the cantilever or the center of the cantilever is detected by the electric detecting means, In the force detection device for detecting a force on the probe, the electrical detection means is attached to a part of the cantilever beam or the both-supported beam.

According to a second aspect of the invention, in the first aspect of the invention, the probe at the tip of the cantilever or at the center of the both cantilevers is made conductive, and a voltage is applied to the conductive probe. Electrical wiring for applying the voltage was formed on the cantilever beam or the both-supported beam.

According to the third aspect of the present invention, the conductive probe provided at the tip of the beam, the electrical wiring for applying a voltage to the conductive probe, and the electrical wire for detecting the bending of the beam. A force detecting device for detecting a force applied to the conductive probe of a cantilever having a detecting means, comprising: a cantilever having the electrical wiring to the conductive probe and a piece having the electrical detecting means. The cantilever and the cantilever are separately provided in the same plane perpendicular to the displacement direction of the beam tip, and the tips of the cantilever provided separately in the same plane are combined into one.

According to a fourth aspect of the present invention, a conductive probe provided at the tip of the beam, electrical wiring for applying a voltage to the conductive probe, and an electrical wire for detecting the bending of the beam. A force detecting device for detecting a force applied to the conductive probe of a cantilever having a detecting means, comprising: a cantilever having the electrical wiring to the conductive probe and a piece having the electrical detecting means. The cantilever and the cantilever are separately provided on different planes perpendicular to the displacement direction of the beam tip, and the tips of the cantilever separately provided on the different planes are combined into one.

According to the fifth aspect of the present invention, a conductive probe provided at the center of the beam, electrical wiring for applying a voltage to the conductive probe, and an electrical wire for detecting the bending of the beam. In a force detection device for detecting a force applied to the conductive probe of a doubly supported beam having a detection means, the electrical wiring is provided on the beam from one fixed end of the doubly supported beam to the conductive probe. In addition, the electrical detection means is provided on the beam from the other fixed end to the conductive probe.

According to a sixth aspect of the present invention, a conductive probe provided at the center of the beam, electrical wiring for applying a voltage to the conductive probe, and an electrical wire for detecting the bending of the beam. In a force detection device for detecting a force applied to the conductive probe of a doubly supported beam having a detection means, a doubly supported beam having the electrical wiring to the conductive probe and a device having the electrical detection means are provided. The cantilever and the cantilever are separately provided on different planes perpendicular to the displacement direction of the beam center, and the centers of the two cantilever beams that are separately provided on the different planes are combined into one.

According to the invention of claim 7, claims 2, 3,
In the invention described in 4, 5, or 6, the electric shield electrode is arranged around the electric detection means for detecting the bending of the cantilever beam or the both-end beam.

According to an eighth aspect of the present invention, a conductive probe provided at the tip or center of the beam, electrical wiring for applying a voltage to the conductive probe, and bending of the beam are detected. In a force detection device for detecting a force applied to the conductive probe of a cantilever beam or a double-supported beam having an electrical detection means, the bending of the beam is detected by a voltage equal to the voltage applied to the conductive probe. It was set to the reference potential of the electrical detection means.

In a ninth aspect of the present invention, a conductive probe provided at the tip or center of the beam, electrical wiring for applying a voltage to the conductive probe, and bending of the beam are detected. In a force detection device for detecting a force applied to the conductive probe of a cantilever or a double-supported beam having an electrical detection means, a voltage in a low frequency band of a voltage applied to the conductive probe is It was set to the reference potential of the electrical detection means for detecting bending.

According to the invention of claim 10, claim 2
In the invention described in 3, 4, 5, 6 or 7, the cantilever or the both-end cantilever having the electrical wiring to the conductive probe has the rigidity of the beam. It is set to be smaller than the rigidity of the cantilever.

[0018]

According to the first aspect of the present invention, a force other than the atomic force does not act between the sample surface and the tip of the probe, and the measurement accuracy can be improved as compared with the conventional case.
In the invention of claim 2, since the bending of the beam is not detected by using the optical system such as the conventional optical lever method,
It is possible to observe and measure the surface state of the photosensitive sample.

According to the third aspect of the invention, the distance between the electrical wiring to the probe and the electrical detecting means becomes large, and no discharge occurs between the probe and the sample, so that the measurement is unsuccessful. It is possible to eliminate things that are possible.

In the invention according to claim 4, the distance between the electrical wiring to the probe and the electrical detection means can be increased without increasing the length of the beam, whereby the probe and the sample can be provided. It becomes possible to perform the measurement without causing discharge between the both and, and it is possible to suppress the probability of damage of the beam at the time of manufacturing the cantilever beam to be low.

According to the fifth aspect of the invention, the distance between the electrical wiring to the probe and the electrical detection means becomes large, and measurement can be performed without causing discharge between the probe and the sample. Become.

According to the sixth aspect of the invention, the distance between the electrical wiring to the probe and the electrical detection means can be increased without increasing the length of the beam. It becomes possible to perform the measurement without causing discharge between the two, and it is possible to suppress the probability of damage of the beam at the time of manufacturing the cantilever beam.

According to the seventh aspect of the invention, it is possible to suppress the inflow of leakage current from the electrical wiring to the probe to the electrical detection means, and improve the measurement accuracy.

According to the eighth aspect of the invention, the potential difference between the electrical wiring to the probe and the electrical detecting means can be made small, which causes discharge between the probe and the sample. It becomes possible to perform the measurement without performing the measurement.

According to the ninth aspect of the invention, the noise current flowing through the parasitic capacitance into the electrical detection means can be reduced, the measurement accuracy can be improved, and the potential of the electrical wiring to the probe can be improved. The potential difference between the probe and the electrical detection means becomes small, and measurement can be performed without causing discharge between the probe and the sample.

According to the tenth aspect of the invention, the rigidity of the entire cantilever beam or the both-end beam is not increased and a complicated resonance state does not occur, so that the detection sensitivity and the measurement accuracy can be improved.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the invention described in claim 1 will be described with reference to FIG. A cantilever 20 made of silicon oxide, which is an insulator, is fixed to a pedestal 19 made of silicon. A probe 21 is formed downward at the tip of the cantilever 20. Further, a piezoresistor 22 made of polycrystalline silicon as an electrical detection means is attached to a part (here, a root part) A of the beam of the cantilever 20. Wirings 23 made of an aluminum thin film are connected to both ends of the piezoresistor 22 for electrical connection with the outside.

In such a structure, the cantilever 20 is deformed by the electrostatic attraction between the charged charges on the surface of the sample (not shown) and the probe 21, and the mechanical deformation amount is determined by the base portion A of the beam. It is possible to measure the force applied to the probe 21 by electrically detecting it by the piezoresistor 22 provided in the, and taking it out to the outside through the wiring 23 and obtaining it as an electrical output.

In the case of the present embodiment, the cantilever 20 is an insulator, and the probe 21 and the piezoresistor 22 of the root portion A are electrically insulated, so that the potential of the piezoresistor 22 changes. Also has no effect on the potential of the probe 21. Therefore, from the above, it is possible to prevent the electrostatic attraction other than the interatomic force from acting between the sample surface and the probe 21 as described above, and to improve the measurement accuracy more than ever. You can

Next, a second embodiment of the invention according to claim 1 will be described with reference to FIG. Here, two cantilever beams 20 are used, and the tip portions are combined into one to form a V shape. A piezoresistor 22 is attached to the root portions A of the two cantilever beams 20.

Also in this case, the probe 21 has the piezoresistor 22.
Since it is insulated from the sample surface, electrostatic attraction force other than the atomic force does not act between the sample surface and the probe 21, thereby further improving the measurement accuracy as in the first embodiment. You can

Next, a third embodiment of the invention according to claim 1 will be described with reference to FIG. Here, the pedestal 19, the cantilever 20, and the probe 21 are integrated by n-type silicon. A piezoresistor 22 of p-type silicon produced by impurity diffusion is provided at the base portion A of the cantilever 20. In this case, the potential of the n-type silicon is set to the ground potential, and the piezoresistor 20 that is p-type silicon is used.
The electric circuit is configured so that the potential of is negative than the ground potential. As a result, the pn junction at the interface between the n-type silicon portion and the piezoresistor 20 is reverse biased, and the two are insulated from each other. Therefore, even if the potential of the piezoresistor 22 changes due to the displacement of the beam, the potential of the probe 21 is GN.
Since it can be left as D, the sample surface and the probe 21
The electrostatic attraction other than the interatomic force does not act between and, and thus the measurement accuracy can be further improved as compared with the conventional case.

Next, a fourth embodiment of the invention according to claim 1 will be described with reference to FIG. A doubly supported beam 24 is formed at the center of the pedestal 19. A probe 21 is provided at the center of the doubly supported beam 24, and piezoresistors 22 are provided at the root portions A of the beams on both sides thereof. Also in this case, as in the first embodiment, the probe 21 and the piezoresistor 22 of the base portion A are electrically insulated, so that even if the potential of the piezoresistor 22 changes, The potential is not affected at all, and the electrostatic attraction other than the atomic force between the sample surface and the probe 21 unlike the conventional case does not act, and the measurement accuracy can be further improved.

Next, a fifth embodiment of the invention according to claim 1 will be described with reference to FIG. A doubly supported beam 24 is formed at the center of the pedestal 19. A probe 21 is provided at the center of the doubly supported beam 24, and a piezoresistor 22 is provided at a portion B near the center (near the probe) of the beams on both sides thereof. Also in this case, as in the first embodiment, the probe 21 and the piezoresistor 22 are electrically insulated from each other. Therefore, even if the potential of the piezoresistor 22 changes, the potential of the probe 21 does not change at all. There is no influence, and no electrostatic attraction other than the atomic force acts between the sample surface and the probe 21 as in the conventional case, and the measurement accuracy can be further improved.

Next, an embodiment of the invention described in claim 2 will be described with reference to FIG. The description of the same parts as those in the first aspect of the present invention will be omitted, and the same reference numerals will be used for the same parts.

Here, the probe at the tip of the cantilever 20 is made conductive (hereinafter referred to as the conductive probe 25) and used as electrical wiring for applying a voltage to the conductive probe 25. The wiring 26 is connected. With such a configuration, an arbitrary voltage is applied to the conductive probe 25 through the wiring 26, and the conductive probe 25 changes from the resistance value change of the piezoresistor 22.
The bending of the cantilever 20 caused by the electrostatic attraction between the charge on the sample surface and the electrostatic charge on the sample surface can be detected, whereby the charge on the sample surface can be measured.

Next, an embodiment of the invention described in claim 3 will be described with reference to FIGS. The description of the same parts as those in the first and second aspects of the present invention is omitted, and the same parts are designated by the same reference numerals.

Here, three cantilever beams 20a, 20
This is a V-shaped beam structure using b and 20c.
That is, in FIG. 6, the wiring 26 to the conductive probe 25 is provided.
One cantilever beam 20c provided at the center having two and two cantilever beams 20a and 20b provided at the left and right respectively having piezoresistors 22a and 22b are perpendicular to the displacement direction Z of the beam tip. Cantilevers 20a to 20 separately provided in the same plane and separately provided in the same plane
The tips of c were joined together. With such a configuration, the distance between the wiring 26 to the conductive probe 25 and the wirings 23a and 23b to the piezoresistors 22a and 22b is set to the above-described embodiment (FIG. Since it can be made much larger than in b)), even if the potential difference between these wirings is extremely large, there is no occurrence of discharge between the two, which prevents the measurement of force detection from becoming impossible. be able to.

As a specific example, according to the well-known Puschen curve, in the case of 1 atmosphere and dry air, if there is a distance of 100 μm or more with respect to the potential difference of 1 KV, no discharge occurs. Therefore, in the example of FIG. 6, the distance D may be 100 μm or more and the distance L may be 200 μm or more, and such a cantilever can be manufactured by micromachining.

7 and 8 show a modification.
In FIG. 7, the piezoresistor 22 is provided on the central cantilever 20c, and the wiring 26 is provided on the two cantilevers 20a and 20b on both sides. Further, in the example of FIG. 8, one of the two cantilevers 20a and 20b is provided with the piezoresistor 22, and the other one is provided with the wiring 26. Even in these cases, since the distance between the wiring 26 and the wiring 23 can be sufficiently maintained, no discharge is generated between the wirings, and thus it becomes possible to prevent the force detection measurement from becoming impossible. be able to.

Next, an embodiment of the invention described in claim 4 will be described with reference to FIG. The description of the same parts as those in the first to third aspects of the present invention is omitted, and the same parts are designated by the same reference numerals.

Here, a cantilever 20a having a wiring 26 to a conductive probe 25 provided at the end of the beam and a cantilever 20b having a piezoresistor 22 are arranged in the displacement direction Z of the beam tip. Provided separately on different planes in the vertical direction,
Cantilever 20a separately provided on the different planes,
The tip of 20b is connected to one. As described above, the two cantilever beams 20a and 20b are stacked on each other with the pedestal 27 interposed therebetween. The lower cantilever beam 20a is provided with the conductive probe 25 and the wiring 26, and the upper cantilever beam 20a is provided. The cantilever 20b is provided with a piezoresistor 22 and a wiring 23. It should be noted that one end of the lower cantilever 20a is fixedly supported by a pedestal 27 and a fixed base 28.

Therefore, with such a vertical structure, the wiring 26 to the conductive probe 25 and the piezoresistor 22 are provided.
Since the distance from the wiring 23 to
It is possible to prevent discharge from occurring between these wirings and prevent measurement from becoming impossible. Moreover,
Since the beams are vertically stacked, the probability of damage to the beams during cantilever production can be kept low. Further, in such a vertical structure, it is possible to omit a space in the horizontal direction.

As a specific example, S having a thickness of 100 μm is used.
When the cantilevers 20a and 20b are manufactured from the i-wafer by the micromachining technique, the distance T becomes 100 μm, and the distance D becomes 200 μm. In the case of 1 atmosphere, 1 KV, and dry air, it is 1 to avoid discharge.
A distance of 00 μm or more is necessary, but since D is 200 μm, discharge can be reliably prevented. In addition, since the length L of the cantilevers 20a and 20b can be set independently of D, L <300 which causes less damage during the manufacturing process.
It can be set in the μm region.

Next, an embodiment of the invention described in claim 5 will be described with reference to FIG. The description of the same parts as those in the first to fourth aspects of the present invention is omitted, and the same parts are designated by the same reference numerals.

Here, a conductive probe 25 is attached to the central portion of the doubly supported beam 24, a wiring 26 is provided on the beam from the conductive probe 25 to one fixed end, and the other fixed end of the beam is provided. A piezoresistor 22 is provided at the base portion A of the. As a result, the conductive probe 25 and the piezoresistor 2
Since the distance D from the wiring 23 to the wiring 2 can be kept constant, it is possible to prevent discharge between the two. As a specific example, if the distance L> 200 μm, D> 100 μm
Therefore, it is possible to sufficiently prevent the discharge.

Next, an embodiment of the invention described in claim 6 will be described with reference to FIG. The description of the same parts as those in the first to fifth aspects of the present invention will be omitted, and the same reference numerals will be used for the same parts.

Here, two double-supported beams 24a and 24b are provided.
It has a structure in which That is, a doubly supported beam 24a having a wiring 26 to the conductive beam 25 provided at the center and a doubly supported beam 24b having piezoresistors 22a and 22b at both ends are perpendicular to the displacement direction Z of the beam center. Are separately provided on different planes in different directions, and the central portions of the doubly supported beams 24a and 24b separately provided on the different planes are coupled to each other via the pedestal 27. Piezoresistor 22
The wirings 23a and 23b connected to a and 22b are connected to electrode pads for external connection on the fixed base.

In this way, the lower supported beam 24a is provided with the conductive probe 25 and the wiring 26, and the upper supported beam 2 is provided.
4b includes piezoresistors 22a and 22b and wirings 23a and 23.
Since b and b are provided, it is possible to reliably prevent discharge. Moreover, since the length L of the beam can be set to <300 as in the fourth aspect of the invention, it is possible to suppress the probability of damage of the beam at the time of producing the cantilever beam to be low.

Next, an embodiment of the invention described in claim 7 will be described with reference to FIG. The description of the same parts as those in the first to sixth aspects of the present invention will be omitted, and the same reference numerals will be used for the same parts.

Here, the piezoresistor 22 for detecting the bending of the cantilever beam 20 (or the both-supported beam may be used) and its wiring 23 are surrounded by the shield electrode 29 as an electric shield electrode. Is provided. The shield electrode 29 is connected to GND, which is a reference of an electric circuit connected to the wirings 23 and 26. This makes it possible to prevent leakage current from the wiring 26 connected to the conductive probe 25 from flowing into the shield electrode 29 and prevent the leakage current from flowing into the piezoresistor 22 and the wiring 23. Therefore, from the above, it is possible to prevent the measurement error due to the leakage current and prevent the deterioration of the measurement level.

Next, an embodiment of the present invention will be described with reference to FIGS. 13 and 14. In addition, claim 1
The description of the same parts as those of the invention described in 7 is omitted, and the same reference numerals are used for the same parts.

FIG. 14 showing the external structure of this embodiment is almost the same as the invention described in claim 3 (see FIG. 6), but the structure of the internal circuit as shown in FIG. 13 is different here. That is, here, the voltage Vt equal to the voltage applied to the conductive probe 25 is set as the reference voltage of the piezoresistors R ₁ and R ₂ for detecting the bending of the beam. The details will be described below.

In FIG. 13, piezoresistors R ₁ and R ₂ are
It forms a Wheatstone bridge circuit with fixed resistors R ₃ and R ₄ . An excitation voltage Vb with the voltage Vt applied to the conductive probe 25 as a reference potential is applied to this bridge circuit.
The value of Vb is the output value of the isolation amplifier 30, and since the reference potential on the output side of this amplifier is Vt, the sum of the reference power supply Vbs and Vt of the bridge applied voltage is the value of Vb. That is, Vb = Vt + Vbs is b of the bridge circuit.
Applied to a point. On the other hand, since the value of Vt is applied to the point d of the bridge circuit, the difference Vbs between the points b and d becomes the excitation voltage of the bridge circuit. Further, since the points a and c are connected to the isolation amplifier 31 in which Vt is the reference potential on the input side and the output side is the reference potential on the ground potential, the voltage of the potential difference between the points a and c with respect to GND. Is output. Vbs is usually 1
A value of 0 V or less is sufficient, and the potential of the conductive probe 25 is Vt. Furthermore, Vc from the controller 33
The output value of Vt obtained through the power amplifier 32 is equal to the charging potential on the sample surface.

From the above, even if Vt is 1 KV
Even in the above case, the potential difference between the conductive probe 25 and the wiring 26 and the piezoresistors R ₁ and R ₂ is 10 V or less, and the potential difference can be remarkably reduced as compared with the previous examples. Therefore, since the potential difference between the wiring 26 to the conductive probe 25 and the wirings 23a and 23b to the piezoresistors R ₁ and R ₂ can be reduced in this way, discharge does not occur between them. A measurement can be made.

Next, an embodiment of the invention described in claim 9 will be described with reference to FIGS. 15 and 16. In addition, claim 1
The description of the same parts as those of the invention described in 8 is omitted, and the same reference numerals are used for the same parts.

FIG. 15 shows the structure of this apparatus.
The basic configuration is the same as the configuration of FIG. 13 described in claim 8 described above. Here, the voltage in the low frequency band of the voltage applied to the conductive probe 25 is set to the reference potential of the piezoresistors R ₁ and R ₂ for detecting the bending of the beam. In order to generate the voltage in the low frequency band, the low pass filter 3
4 is provided. The external configuration of this device is the same as that shown in FIG. The details will be described below.

The output Vc from the controller 33, which has passed through the low-pass filter 34, is amplified by the power amplifier 32a, and the voltage Vs is used as the reference potential of the bridge circuit. As a result, the waveform obtained by removing the high frequency component of Vt becomes Vs, so that the noise current flowing into Vb through Cs can be reduced, and the measurement error can be reduced. In addition, the voltage Vt via the power amplifier 32b is set to be equal to the charging potential on the surface of the sample by the controller 3
3 controls, the surface potential Vs is shown in FIG. 16 when the sample is scanned with respect to the conductive probe 25 or when the spatial frequency of the charged charge distribution becomes high.
As shown in the P-side region, the amplitude thereof has a characteristic of becoming smaller, and as a result, the potential difference between Vs and Vt from which the high frequency component of Vt is removed becomes smaller as the frequency becomes higher. On the other hand, in the case of the low frequency in the Q region of FIG. 16, the low-pass filter 34 does not remove the low-frequency component, so that Vs and Vt have substantially the same potential, which results in Vt.
The potential difference between Vs and Vt becomes small regardless of the frequency.
Therefore, because of this, there is no potential difference between the wiring 26 to the conductive probe 25 and the wirings 23a and 23b to the piezoresistors R ₁ and R ₂ , so that discharge between these wirings is prevented. You can

Next, an embodiment of the invention described in claim 10 will be described with reference to FIGS. In addition, claim 1
The description of the same parts as those in the invention described in 9 is omitted, and the same reference numerals are used for the same parts.

Here, the rigidity of the cantilever beam or the both-end supported beam having electrical wiring to the conductive probe is higher than the rigidity of the cantilever beam or the both-end supported beam having the electrical detecting means. I set it small. Specifically, in FIG. 17 (almost the same as the configuration of FIG. 6), the conductive probe 2
The rigidity of the beam in the cantilever 20c having the wiring 26 to 5 is determined by the cantilever 20 having the piezoresistors 22a and 22b.
It is set to be smaller than the rigidity of the beams in a and 20b. In order to change the rigidity of the beam, the beam width Wc of the cantilever beam 20c is set smaller than the beam widths Wa and Wb of the cantilever beams 20a and 20b.

By making the rigidity of the cantilever 20c smaller than the rigidity of the cantilevers 20a and 20b, the spring constant of the entire beam has the wiring 26 to the conductive probe 25. There is no need to raise it significantly. Further, as a result, the cantilever beam 20c having the wiring 26 to the conductive probe 25 follows the movement of the cantilever beams 20a and 20b having the piezoresistors 22a and 22b. It never happens. Therefore, since the rigidity of the entire beam is not increased and a complicated resonance state does not occur, the detection sensitivity and the measurement accuracy can be further improved.

18 and 19 show a modification. In FIG. 18 (substantially the same as the configuration of FIG. 7), two cantilever beams 20a on both sides having a wiring 26 to a conductive probe 25,
By making the beam widths Wa and Wb of 20b smaller than the beam width Wc of the cantilever beam 20c having the piezoresistor 22,
The rigidity of the cantilevers 20a and 20b is made smaller than the rigidity of the cantilever 20c. Further, in FIG. 19 (almost the same as the configuration of FIG. 9), a cantilever 20b having a piezoresistor 22 is provided.
A beam thickness t _b, by forming thicker than beam thickness t _a of the cantilever 20a having a wiring 26 to the conductive probe 25, than the stiffness of the stiffness of the cantilever 20a cantilever 20b I'm making it small. Therefore, even in these cases, the rigidity of the entire beam is not increased, and a complicated resonance state does not occur,
The detection sensitivity and measurement accuracy can be further improved.

[0063]

According to the first aspect of the invention, the bending caused by the force applied to the probe at the tip of the cantilever or the center of the cantilever is applied to the probe by detecting the bending caused by the electric detection means. In the force detection device for detecting a force, since the electrical detection means is attached to a part of the beam of the cantilever or the both-supported beam, a force other than the atomic force is applied between the sample surface and the tip of the probe. Since it does not work, the measurement accuracy can be improved more than ever before.

According to a second aspect of the present invention, in the first aspect of the present invention, the probe at the tip of the cantilever or at the center of the double-supported beam is made conductive, and a voltage is applied to the conductive probe. Since the electrical wiring for applying the voltage is formed on the beam of the cantilever beam or the both-supported beam, the bending of the beam is not detected by using the optical system such as the conventional optical lever method, and the photosensitivity is improved. The surface condition of the sample can be observed and measured.

According to a third aspect of the present invention, a conductive probe provided at the tip of the beam, electrical wiring for applying a voltage to the conductive probe, and an electrical wire for detecting the bending of the beam. A force detecting device for detecting a force applied to the conductive probe of a cantilever having a detecting means, comprising: a cantilever having the electrical wiring to the conductive probe and a piece having the electrical detecting means. Since the cantilever and the cantilever are separately provided in the same plane perpendicular to the displacement direction of the beam tip, and the tips of the cantilever provided separately in the same plane are combined into one,
The distance between the electrical wiring to the probe and the electrical detection means becomes large, and the discharge between the probe and the sample does not occur, so that the measurement can be performed reliably. is there.

According to a fourth aspect of the present invention, a conductive probe provided at the tip of the beam, electrical wiring for applying a voltage to the conductive probe, and an electrical wire for detecting the bending of the beam. A force detecting device for detecting a force applied to the conductive probe of a cantilever having a detecting means, comprising: a cantilever having the electrical wiring to the conductive probe and a piece having the electrical detecting means. Since the cantilever and the cantilever are separately provided in different planes perpendicular to the displacement direction of the beam tip, and the tips of the cantilever provided separately in the different planes are combined into one,
It is possible to increase the distance between the electrical wiring to the probe and the electrical detection means without increasing the length of the beam, which allows measurement without causing discharge between the probe and the sample. This can be surely performed, and the probability of beam damage during cantilever production can be suppressed to a low level.

According to a fifth aspect of the present invention, a conductive probe provided at the center of the beam, electrical wiring for applying a voltage to the conductive probe, and an electrical wire for detecting bending of the beam are provided. In a force detection device for detecting a force applied to the conductive probe of a doubly supported beam having a detection means, the electrical wiring is provided on the beam from one fixed end of the doubly supported beam to the conductive probe. Since the electric detection means is provided on the beam from the other fixed end to the conductive probe, the distance between the electric wiring to the probe and the electric detection means increases, The discharge between the needle and the sample is not generated, and the measurement can be reliably performed.

According to a sixth aspect of the present invention, a conductive probe provided at the center of the beam, electrical wiring for applying a voltage to the conductive probe, and an electrical wire for detecting the bending of the beam. In a force detection device for detecting a force applied to the conductive probe of a doubly supported beam having a detection means, a doubly supported beam having the electrical wiring to the conductive probe and a device having the electrical detection means are provided. Since the cantilever and the cantilever are separately provided on different planes perpendicular to the displacement direction of the beam center, and the centers of the doubly supported beams separately provided on the different planes are combined into one,
It is possible to increase the distance between the electrical wiring to the probe and the electrical detection means without increasing the length of the beam, thereby preventing the discharge between the probe and the sample. The measurement can be performed reliably, and the probability of damage to the beam during cantilever production can be suppressed to a low level.

The invention described in claim 7 is,
In the invention described in 4, 5, or 6, since the electric shield electrode is arranged around the electric detection means for detecting the bending of the cantilever beam or the both-end beam, the electric detection is performed from the electric wiring to the probe. It is possible to suppress the inflow of leakage current into the means and improve the measurement accuracy.

According to an eighth aspect of the present invention, a conductive probe provided at the tip or center of the beam, electrical wiring for applying a voltage to the conductive probe, and bending of the beam are detected. In a force detection device for detecting a force applied to the conductive probe of a cantilever beam or a double-supported beam having an electrical detection means, the bending of the beam is detected by a voltage equal to the voltage applied to the conductive probe. Since it is set to the reference potential of the electrical detection means, the potential difference between the electrical wiring to the probe and the electrical detection means can be made small, which can prevent the discharge between the probe and the sample. It is possible to reliably perform the measurement without causing the occurrence.

According to a ninth aspect of the present invention, a conductive probe provided at the tip or the center of the beam, electrical wiring for applying a voltage to the conductive probe, and bending of the beam are detected. In a force detection device for detecting a force applied to the conductive probe of a cantilever or a double-supported beam having an electrical detection means, a voltage in a low frequency band of a voltage applied to the conductive probe is Since it is set to the reference potential of the electrical detection means for detecting the bend, it is possible to reduce the inflow of noise current into the electrical detection means through the parasitic capacitance and improve the measurement accuracy. Since the potential difference between the electric wire and the electric detection means becomes small, the discharge between the probe and the sample does not occur, and the measurement can be performed reliably.

The invention described in claim 10 is,
In the invention described in 4, 5, 6 or 7, the cantilever beam or the both-end beam having an electric detecting means for measuring the rigidity of the beam in the cantilever beam or the both-end beam having electrical wiring to the conductive probe. Since it is set to be smaller than the rigidity of the beam in, the rigidity of the entire cantilever beam or both-end supported beam does not become high, a complicated resonance state does not occur, and detection sensitivity and measurement accuracy can be improved. Is.

[Brief description of drawings]

FIG. 1 (a) is a sectional view showing the configuration of a force detection device according to a first embodiment of the invention described in claim 1, and FIG. 1 (b) is a top view.

FIG. 2 is a plan view showing a second embodiment of the invention according to claim 1;

FIG. 3 is a sectional view showing a third embodiment of the invention according to claim 1.

4A is a sectional view showing a fourth embodiment of the invention as set forth in claim 1, and FIG. 4B is a bottom view.

5A is a sectional view showing an embodiment of the invention described in claim 2, and FIG. 5B is a top view.

6A is a sectional view showing an embodiment of the invention described in claim 3, and FIG. 6B is a top view.

FIG. 7 is a plan view showing another example of the invention according to claim 3;

FIG. 8 is a plan view showing another example of the invention according to claim 3;

9A is a top view showing an embodiment of the invention described in claim 4, FIG. 9B is a sectional view, and FIG. 9C is a bottom view.

10A is a side view showing an embodiment of the invention described in claim 5, and FIG. 10B is a bottom view.

11A is a top view showing an embodiment of the invention described in claim 6, FIG. 11B is a sectional view, and FIG. 11C is a bottom view.

FIG. 12 is a plan view showing an embodiment of the invention as set forth in claim 7;

FIG. 13 is a circuit configuration diagram showing an embodiment of the invention as set forth in claim 8;

FIG. 14 is a plan view showing the configuration of a force detection device.

FIG. 15 is a circuit configuration diagram showing an embodiment of the invention as set forth in claim 9;

FIG. 16 is a characteristic diagram showing amplitude characteristics.

FIG. 17 is a plan view showing an embodiment of the invention as set forth in claim 10;

FIG. 18 is a plan view showing another example of the invention according to claim 10;

FIG. 19 is a sectional view showing another example of the invention according to claim 10;

20A is a sectional view showing a first conventional example, FIG.
Is a top view.

FIG. 21 is a circuit diagram.

FIG. 22 is a configuration diagram showing a second conventional example.

23 (a) is a sectional view showing a fifth embodiment of the invention as set forth in claim 1, and FIG. 23 (b) is a bottom view.

[Explanation of symbols]

 20 cantilever 21 probe 22 electrical detection means 24 doubly supported beam 25 conductive probe 26 electrical wiring 29 electrical shield electrode

Claims (10)

[Claims] 1. A force detection device for detecting the force applied to the probe by detecting the bending caused by the force applied to the probe at the tip of the cantilever or the center of the cantilever with an electrical detection means. A force detecting device, wherein the electrical detecting means is attached to a part of the cantilever beam or the beam of the both-end supporting beam. 2. A probe at the tip of the cantilever or at the center of the cantilever is made conductive, and electrical wiring for applying a voltage to the conductive probe is provided at the cantilever or the The double-supported beam is formed on the beam.
The force detection device described. 3. A piece having a conductive probe provided at the tip of the beam, electrical wiring for applying a voltage to the conductive probe, and electrical detection means for detecting bending of the beam. In a force detecting device for detecting a force applied to the conductive probe of a cantilever, a cantilever having the electrical wiring to the conductive probe and a cantilever having the electrical detecting means are provided at the tip of the beam. The force detecting device is characterized in that the cantilever beams are separately provided in the same plane perpendicular to the displacement direction, and the tips of the cantilever beams provided separately in the same plane are combined into one. 4. A piece having a conductive probe provided at the tip of a beam, electrical wiring for applying a voltage to the conductive probe, and an electrical detection means for detecting bending of the beam. In a force detecting device for detecting a force applied to the conductive probe of a cantilever, a cantilever having the electrical wiring to the conductive probe and a cantilever having the electrical detecting means are provided at the tip of the beam. Of the cantilever provided separately on different planes perpendicular to the displacement direction, and the tip ends of the cantilever beams provided separately on the different planes are combined into one. 5. A conductive probe provided in the center of a beam, electrical wiring for applying a voltage to the conductive probe, and electrical detection means for detecting bending of the beam. In a force detection device for detecting a force applied to the conductive probe of a cantilever, the electric wiring is provided on the beam from one fixed end of the both-supported beams to the conductive probe, and the other of the two is supported. A force detecting device having an electric detecting means on a beam from a fixed end to the conductive probe. 6. A conductive probe provided in the center of a beam, electrical wiring for applying a voltage to the conductive probe, and electrical detection means for detecting bending of the beam. In a force detection device for detecting a force applied to the conductive probe of a cantilever, a doubly supported beam having the electrical wiring to the conductive probe and a doubly supported beam having the electrical detection means are centered on the beam. The force detection device is characterized in that it is separately provided on different planes perpendicular to the displacement direction of the above, and the centers of the two doubly supported beams that are provided separately on the different planes are combined into one. 7. The electric shield electrode is arranged around an electric detection means for detecting the bending of the cantilever beam or the both-end supported beam, according to claim 2, 3, 4, 5 or 6. Force detection device. 8. A conductive probe provided at the tip or the center of the beam, electrical wiring for applying a voltage to the conductive probe, and electrical detection means for detecting the bending of the beam. In a force detection device for detecting a force applied to the conductive probe of a cantilever or a doubly supported beam, a voltage equal to the voltage applied to the conductive probe is detected by an electrical detection means for detecting the bending of the beam. A force detection device characterized by being set to a reference potential. 9. A conductive probe provided at the tip or the center of the beam, electrical wiring for applying a voltage to the conductive probe, and electrical detection means for detecting bending of the beam. In a force detection device for detecting a force applied to the conductive probe of a cantilever or a doubly supported beam, a voltage in a low frequency band of a voltage applied to the conductive probe is electrically detected to detect bending of the beam. A force detection device characterized by being set to a reference potential of detection means. 10. The rigidity of a cantilever beam or a double-supported beam having electrical wiring to a conductive probe is smaller than the rigidity of the beam of the cantilever beam or the double-supported beam having an electrical detection means. The force detection device according to claim 2, 3, 4, 5, 6 or 7, wherein the force detection device is set.