JPH0625642B2 - Scanning tunnel microscope device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to an improvement of a scanning tunneling microscope apparatus for observing a surface shape or the like of a substance with high accuracy in a non-contact manner.

(Prior Art) Recently, as a microscope apparatus for observing a minute observation object, as shown in US Pat. No. 4,434,993, for example, a scanning tunnel microscope (hereinafter referred to as STM) having a high resolution so that atoms can be observed. The device is being developed. This is because the tip of the probe provided on the microscope main body is brought close to the observation target to about 1 nm where the electron cloud of the atom at the tip of the probe and the electron cloud of the atom of the observation target (sample) overlap with each other, and in this state Measure the magnitude of the tunnel current that flows when a voltage is applied between the needle and the observation object, and based on this measurement result, measure the distance between the probe and the observation object with ultra precision. It was done. In this case, the magnitude of the tunnel current changes exponentially according to the distance between the probe and the observation object. Therefore, in STM, the tip of the probe is set to 1 nm as the observation target by utilizing the distance dependence of the tunnel current.
With this probe, the surface of the object to be observed is two-dimensionally scanned in a state of being close enough to measure the magnitude of the tunnel current at each measuring point on the surface of the object to be observed and the probe at each measuring point. The three-dimensional image of the surface of the observation object is obtained by measuring the distance to the object with ultra precision and plotting the distance measured at each measurement point. In actual measurement, it is difficult to detect the distance between the probe and the object to be observed with high accuracy.Therefore, follow the unevenness of the surface of the object to observe the probe so that the tunnel current is constant. Scanning is performed while operating, and a three-dimensional image of the surface of the observation object is obtained based on the vertical movement of the probe.

By the way, as a probe scanning means in this type of STM, conventionally, as shown in FIG. 13, a fine movement mechanism called tripod a in which PZT of piezoelectric ceramics is orthogonal to the XYZ directions, or a cylinder as shown in FIG. A tube scanner c or the like in which an electrode Z is adhered to the inner peripheral surface of the piezoelectric ceramic b and electrodes x, y, -x, -y are adhered to the outer peripheral surface thereof is widely used.

Further, a mechanism for enlarging the scanning region using a parallel type parallel spring as shown in the literature, for example, pp. 249-250, Proceedings of the Autumn Meeting of the Precision Engineering Society of Japan 1987 has been considered.

(Problems to be solved by the invention) When a tripod a type fine movement mechanism, a tube scanner c, or the like is used as the scanning means of the probe, the scanning range is limited by the displacement amount of the drive element. However, there is a problem that a large scanning range cannot be obtained. Therefore, the tripod a type fine movement mechanism, the tube scanner c, and the like have a problem that the surface of the observation object cannot be measured over a wide range because the scanning area is narrow.

Further, in the case of a scanning area enlarging mechanism using a superimposing parallel spring, the probe is configured to be driven in the horizontal direction, so that the observation object holding surface of the table holding the observation object is set in the vertical direction. There was a problem that had to be placed along. Therefore, since it is necessary to firmly fix the observation target to the observation target holding surface of the table, it is difficult to provide a mechanism for moving the attachment position of the observation target, and the observation area of the observation target is limited. was there. further,
There is also a problem that the size, thickness, weight, etc. of the observation object that can be attached to the observation object holding surface of the table are limited.

The present invention has been made in view of the above circumstances, and it is possible to enlarge the observation area of the sample surface, measure the fine structure of the sample surface with high accuracy, and limit the size of the sample. It is an object of the present invention to provide a scanning tunneling microscope apparatus that can be reduced in number and can increase the supporting rigidity of a table that holds a sample and can stably perform the measurement operation of the sample surface.

[Structure of the Invention] (Means for Solving the Problems) In the present invention, the tables holding the sample are orthogonal to each other.
A table drive mechanism for two-dimensionally scanning in a direction and a probe drive mechanism for driving a probe for detecting a minute current, which is arranged to face a sample on the table, in a direction perpendicular to the scanning direction of the table, With the scanning of the table, the probe was moved to the sample above until the electron clouds of both were overlapped and the tunnel current flowing when a potential difference was applied between the two was kept constant. In a scanning tunneling microscope device that measures the surface shape of a sample on the table by driving in a direction perpendicular to the scanning direction of the table, the tables are orthogonal to each other along a horizontal plane due to a displacement operation of a bimorph type piezoelectric element. A table fine movement mechanism for performing a two-dimensional fine displacement in two directions, and the table fine movement mechanism in the same direction as the driving direction of the table fine movement mechanism. The table drive mechanism is provided with a table coarse movement mechanism that coarsely moves the table with a displacement amount larger than the displacement amount by the table coarse movement mechanism side at both ends of the bimorph type piezoelectric element. And a fixed portion, a connection portion with the table side is provided at a substantially central portion of the bimorph type piezoelectric element, and a polarization direction at a plurality of predetermined portions between the both ends of the bimorph type piezoelectric element is predetermined. Further, by dividing the electrodes of the bimorph type piezoelectric element corresponding to the predetermined portion and applying a voltage to the electrodes, the portion between the both ends of the bimorph type piezoelectric element is deformed into a substantially arc shape, and A displacement amount amplifying means for amplifying the displacement amount of the bimorph type piezoelectric element is provided.

(Operation) By coarsely moving the holding table of the sample in two directions orthogonal to each other by a large displacement amount by the table coarse movement mechanism, the observation area of the sample surface is enlarged, and at the same time by the fine movement mechanism, the tables are orthogonal to each other along the horizontal plane. To do 2
By finely displacing two-dimensionally in the direction, the fine structure of the sample surface can be accurately measured. Furthermore, by supporting the bimorph type piezoelectric element at both ends, the support rigidity of the table is increased, and the displacement amount amplifying means in which the electrodes of the bimorph type piezoelectric element are divided is used to amplify the displacement amount of the bimorph type piezoelectric element. It was done.

(Embodiment) An embodiment of the present invention will be described below with reference to FIGS. 1 to 8. FIG. 1 shows a schematic configuration of a main part of the scanning tunneling microscope apparatus. Reference numeral 1 is a scanning tunneling microscope apparatus main body, and 2 is a base of the microscope apparatus main body 1. On the base 2, a table drive mechanism 5 for two-dimensionally scanning the holding table 4 of the sample 3 in two directions (X direction and Y direction) orthogonal to each other and a Z-axis mechanism (probe drive mechanism) 6 described later are provided. Columns 7 for supporting each are provided.

Further, the table 4 is arranged in the table drive mechanism 5 in two directions (X direction and Y direction) orthogonal to each other along the horizontal plane.
A table fine movement mechanism 8 for performing a minute displacement in a dimension, and a table coarse movement mechanism 24 for coarsely moving the table 4 in the same direction as the driving direction of the table fine movement mechanism 8 by a displacement amount larger than the displacement amount by the table fine movement mechanism 8 are provided. Has been.

Further, the table fine movement mechanism 8 includes an X-direction fine movement mechanism 9 for finely displacing the table 4 in the X direction along the horizontal plane, and a fine movement of the table 4 along the horizontal plane in the Y direction orthogonal to the displacement direction of the X direction fine movement mechanism 9. Displacement Y direction fine movement mechanism 1
0 and 0 are provided in a state of being vertically stacked.

FIG. 2 shows a schematic configuration of the X-direction fine movement mechanism 9. In FIG. 2, 11 is the main body of the X-direction fine movement mechanism.
The fine movement mechanism main body 11 is provided with a flat plate-shaped fixing plate 15. At the center of the fixed plate 15, a holding table 4 for the sample 3 is arranged so as to be movable in the X direction.

Further, on both side surfaces of the table 4, the projections 1 are directed in the X direction.
4a and 14b are projected. The central portion of two thin plate-shaped bimorph-type piezoelectric elements 12a and 12b extending in the Y direction is connected to one protrusion 14a, and the other protrusion 14b also extends in the Y direction. The central portions of the two thin plate-shaped bimorph-type piezoelectric elements 13a and 13b are connected.

In this case, the two sets of bimorph type piezoelectric elements 12a and 12b on the side of the protrusion 14a are arranged in parallel and face each other in the state of being separated in the X direction, and the two sets of bimorph type piezoelectric elements 13a and 13b on the side of the protrusion 14b are also arranged. Similarly, they are arranged so as to face each other substantially in parallel while being separated in the X direction.

Further, on the fixing plate 15 of the fine movement mechanism main body 11, support projections 16a, 16b, 1
7a and 17b are provided so as to project at substantially right angles. In this case, the pair of support protrusions 16 a, 1 on one end side of the fixed plate 15
6b is arranged on one of the protrusions 14a of the table 4 so as to be spaced apart and opposed thereto. A pair of slits into which the bimorph type piezoelectric elements 12a and 12b are inserted are formed in the support protrusions 16a and 16b, respectively. Both ends of the two pairs of bimorph type piezoelectric elements 12a and 12b are provided with the support projection 16
The bimorph type piezoelectric elements 12a and 12b are fixed in a state of being inserted into the slits a and 16b, and have a structure of supporting both ends.

Similarly, a pair of support protrusions 17a on the other end side of the fixed plate 15,
17b is arranged on the other protruding portion 14b of the table 4 so as to be separated and opposed thereto. A pair of slits into which the bimorph type piezoelectric elements 13a and 13b are inserted are formed in the support protrusions 17a and 17b, respectively. Both ends of the two pairs of bimorph-type piezoelectric elements 13a and 13b have support projections 17
The bimorph type piezoelectric elements 13a and 13b are fixed in a state of being inserted into the slits a and 17b, and have a structure of supporting both ends.

3 and 4 show each bimorph type piezoelectric element 1
2 shows a schematic configuration of 2a, 12b, 13a, 13b. That is, each bimorph type piezoelectric element 12a, 12
As shown in FIG. 3, b, 13a, and 13b are formed by bonding two piezoelectric elements A and B, which expand and contract in the lengthwise direction when a voltage is applied, via a central electrode 22.

Further, each bimorph type piezoelectric element 12a, 12b, 13
On the outer surface of one of the piezoelectric elements A constituting a and 13b, a fourth
As shown in the figure, a plurality of divided electrodes 18a, 19a, 20
a and 21a are arranged in parallel, and the divided electrodes 18a, 19a, 20a and 21 are formed on the outer surface of the other piezoelectric element B.
The divided electrodes 18b, 19b, 20b, at positions corresponding to a.
21b are arranged side by side.

In addition, each of the bimorph type piezoelectric elements 12a, 12b, 13
One of the divided electrodes 18a,
19a, 20a, 21a and the central electrode 22, and the piezoelectric element B on the other side is divided into respective divided electrodes 18b, 19b, 2a.
A bias voltage is previously applied between 0b and 21b and the central electrode 22 in the polarization direction shown by the arrow in FIG.

That is, the piezoelectric element A includes the divided electrodes 18a, 19a,
Bias voltages are applied in advance to the respective sections between 20a and 21a and the central electrode 22 in different polarization directions. Here, in the section between the split electrode 18a and the central electrode 22, the polarization direction is − and the central electrode 22 is +, and the voltage is applied, and the polarization is performed in the section between the split electrode 19a and the central electrode 22. In the direction, the split electrode 19a is +, and the central electrode 22 is −, and a voltage is applied. Furthermore, the split electrode 20
In the section between a and the central electrode 22, the divided electrodes 20a are polarized with a voltage of +, and the central electrode 22 is applied with a voltage, and in the section between the divided electrode 21a and the central electrode 22, the polarized direction is the divided electrode 21a. , And the central electrode 22 is +, and a voltage is applied.

In addition, the piezoelectric element B includes the divided electrodes 18b, 19b, 20.
Bias voltages are applied in advance to the sections between the electrodes b and 21b and the central electrode 22 in different polarization directions, and in the section between the split electrodes 18b and the central electrode 22, the polarization direction is + for the split electrode 18b and the central electrode. 22 is-and a voltage is applied,
In the section between the divided electrode 19b and the central electrode 22, the polarization direction is − for the divided electrode 19b and + for the central electrode 22, and a voltage is applied. Further, in the section between the divided electrode 20b and the central electrode 22, the polarization direction is − and the central electrode 22 is +, and the polarization direction is applied in the section between the divided electrode 21b and the central electrode 22. Is the divided electrode 21b is +,
A voltage is applied when the central electrode 22 is negative.

Further, FIG. 5 shows each bimorph type piezoelectric element 12a, 12
b, 13a, 13b divided electrodes 18a, 19a, 20
The wiring state between a, 21a, 18b, 19b, 20b, 21b and the electrode 22 and the driving power supply is shown.

The fine-movement mechanism main body 11 has the bimorph-type piezoelectric elements 12a, 12b, 13a, 13b in a non-operating state in which a drive voltage is not applied to the bimorph-type piezoelectric elements 12a, 12b, 13a as shown by the solid line in FIG. , 13b are each held in a substantially linear normal state. In this state, the table 4 is held at the central neutral position of the holding table 4.

In addition, each of the bimorph type piezoelectric elements 12a, 12b, 13
When a drive voltage is applied to a and 13b, the two piezoelectric elements A and B forming each bimorph type piezoelectric element 12a, 12b, 13a and 13b are deformed as follows. That is, a bias voltage is applied in advance to the piezoelectric element A in the section between the divided electrode 18a and the central electrode 22 in the polarization direction of FIG. 3 (the divided electrode 18a is − and the central electrode 22 is +), and the fifth voltage is applied.
When a drive voltage is applied as shown, the piezoelectric element A expands in this section. At this time, in the piezoelectric element B in the section between the divided electrode 18b and the central electrode 22 on the opposite side, the polarization direction (+ for the divided electrode 18b, − for the central electrode 22) is opposite to that of the piezoelectric element A, and therefore FIG. When the same drive voltage is applied as described above, the piezoelectric element B contracts in this section.

The same applies to the piezoelectric element A in the section between the divided electrode 21a and the central electrode 22 and the piezoelectric element B in the section between the divided electrode 21b and the central electrode 22. Therefore, the inner sides of the portions at both ends of each bimorph type piezoelectric element 12a, 12b, 13a, 13b (the section between the divided electrodes 18a, 18b and the section between the divided electrodes 21a, 21b) are curved downward in FIG. It will be.

Further, in the piezoelectric element A in the section between the divided electrode 19a and the electrode 22, the polarization direction (the divided electrode 19a is +,
When a bias voltage is applied to the central electrode 22 by-) and a drive voltage is applied as shown in FIG. 5, the piezoelectric element A contracts in this section. At this time, the divided electrode 19b and the electrode 2 on the opposite side are
In the piezoelectric element B in the section between 2 and 2, the polarization direction (divided electrode 1
Since 9b is − and the central electrode 22 is +, which is opposite to the piezoelectric element A, when the same drive voltage is applied as shown in FIG. 5, the piezoelectric element B expands in this section.

The same applies to the piezoelectric element A in the section between the split electrode 20a and the central electrode 22 and the piezoelectric element B in the section between the split electrode 20b and the central electrode 22. Therefore, the bimorph type piezoelectric elements 12a, 12b, 13a, 13b are located in the central portion (the section between the divided electrodes 19a, 19b and the divided electrode 2).
The section between 0a and 20b) is curved as a whole so as to project downward as shown by the phantom line in FIG.

Therefore, at the time of applying the drive voltage, each bimorph type piezoelectric element 12a, 12b, 13a, 13b has its both ends (the section between the divided electrodes 18a, 18b and the divided electrode 21a,
In the section between 21b), the piezoelectric element A extends in the longitudinal direction and at the same time the piezoelectric element B deforms in the direction of contracting in the longitudinal direction, and inside the both end deformed portions (divided electrodes 19a, 19b).
In the interval between and between the divided electrodes 20a and 20b), the piezoelectric element B extends in the length direction and at the same time, the piezoelectric element A deforms in the direction of contracting in the length direction, and each bimorph type piezoelectric element 1
The whole of 2a, 12b, 13a, 13b is adapted to be deformed downward in a substantially bow shape as shown by an imaginary line in FIG. Thereby, the bimorph type piezoelectric elements 12a, 1
Displacement amount amplification means for amplifying the displacement amount of the bimorph type piezoelectric elements 12a, 12b, 13a, 13b by dividing the electrodes 2b, 13a, 13b is configured.

The Y-direction fine movement mechanism 10 is substantially the same as the X-direction fine movement mechanism 9. In this case, the table 4 of the Y direction fine movement mechanism 10 is fixed to the lower surface of the fixing plate 15 of the X direction fine movement mechanism 9.

Further, projections 14a and 14b are provided on both side surfaces of the table 4 of the Y-direction fine movement mechanism 10 so as to extend in the Y-direction. Then, on one of the protrusions 14a, two thin plate-shaped bimorph type piezoelectric elements 12a, 12b extending in the X direction are provided.
Of the thin plate-like bimorph type piezoelectric elements 13a and 13b extending in the X direction are also connected to the other projecting portion 14b. The table 4 is displaced in the Y direction by the deformation of 12a, 12b, 13a, 13b. Each bimorph type piezoelectric element 12a, 12b, 13a, 13b of the Y direction fine movement mechanism 10 also has a structure of supporting both ends similarly to the X direction fine movement mechanism 9.

Further, the microscope apparatus main body 1 is provided with a coarse movement mechanism 24 that coarsely moves the table 4 in the same direction as the driving direction of the fine movement mechanism 8 by a displacement amount larger than the displacement amount by the fine movement mechanism 8.
The coarse movement mechanism 24 includes an X-direction coarse movement mechanism 25 for roughly moving the table 4 in the X direction along the horizontal plane and a Y direction coarse movement mechanism 26 for roughly moving the table 4 in the Y direction along the horizontal plane. It is provided in a state of being stacked in layers. In this case, the X-direction coarse movement mechanism 25 and the Y-direction coarse movement mechanism 26 are formed by, for example, a micrometer.

Further, a tilt stage 27 for correcting the tilt of the sample 3 on the table 4 is provided on the base 2 of the microscope apparatus main body 1.

The tilt stage 27 has a cutout portion 2 extending in a substantially horizontal direction.
8 is formed. In this case, the cutouts 28 are provided in two steps, one above the other as shown in FIG. Then, in FIG. 7, the upper end portion 27a of the first notch portion 28a of the tilt stage 27 is provided at the end of the upper first notch portion 28a.
A hinge portion 111a for swingably supporting the is formed.

Furthermore, the upper portion 2 of the second notch portion 28b of the tilt stage 27 is provided at the end of the lower second notch portion 28b.
A hinge portion 111b that swingably supports 7a is formed. In addition, the axial center directions of the swing shafts of the upper and lower hinge portions 111a and 111b are arranged orthogonally.

Further, the tilt stage 2 is provided on the upper surface of the tilt stage 27.
7, the tension screw portion 101 and the pressing screw portion 102 for swinging the upper portion 27a of the first cutout portion 28a.
And a tension screw portion 101 'and a pressing screw portion 102' for swinging the upper portion 27a of the second cutout portion 28b of the tilt stage 27.

Here, as shown in FIG. 8, the tension screw portion 101 is provided with a fixing screw 104 that is inserted into the insertion hole 103 formed in the upper portion 27a of the first cutout portion 28a of the tilt stage 27. . The lower end portion of the fixing screw 104 has a first cutout portion 28 a in the tilt stage 27.
It is fixed to the lower part 27b.

Further, the upper end portion of the fixing screw 104 is projected above the insertion hole 103, and the tilt adjusting nut 105 is screwed to the protruding portion.

Further, the pressing screw portion 102 is provided with a pressing screw 107 that is screwed into a screw hole 106 formed in the upper portion 27a of the first cutout portion 28a of the tilt stage 27.

Then, the tilt adjusting nut 105 or the pressing screw 107
The hinge portion 111a is elastically deformed in accordance with the adjustment of the screwing amount, and the upper portion 27a of the first cutout portion 28a of the tilt stage 27 is swung about the hinge portion 111a, so that the sample 3 on the table 4 It is designed to correct the tilt.

Further, a probe 29 for detecting a minute current is arranged above the sample 3 on the table 4 so as to face it. This probe 29 has a length of several mm to several tens of mm and a diameter of several mm or less, and the tip of a tip made of dangsten or platinum is sharpened to a diameter of about 0.1 μm or less by means such as electrolytic polishing or machining (grinding). It can be processed. Then, the Z-axis mechanism 6 that drives the probe 29 in the direction perpendicular to the scanning direction of the table 4
The base end portion of the probe 29 is fixed to the fine movement mechanism 30.

The Z-axis mechanism 6 includes a screw feed type first coarse movement mechanism 31 mounted on the upper end of the column 7, and the first coarse movement mechanism 3
Second coarse movement mechanism 32 by a parallel spring attached to No. 1 and fine movement mechanism 3 attached to this second coarse movement mechanism 32
0 is provided for each. The fine movement mechanism 30 is formed by a single piezoelectric element.

Further, FIG. 6 shows a control circuit of the scanning tunneling microscope apparatus main body 1. In FIG. 6, reference numeral 33 is a control unit formed by, for example, a microcomputer and its peripheral circuits. The control unit 33 includes an A / D converter 34.
And a D / A converter 35 are connected to each other, and an operation unit 36 such as a keyboard and x
A display unit 37 formed by a CRT or the like having a y-blotter and an image memory for density display is connected to each. Further, the A / D converter 34 includes a control circuit 3
8 is connected. This control circuit 38 includes a comparison amplifier 3
It is connected to the reference power source 40 via 9. Further, the probe 29 is connected to the comparison amplifier 39 via an amplifier 41. Further, the Z-axis fine movement mechanism 30 is connected to the control circuit 38 via a drive circuit 42.

Further, the D / A converter 35 is connected to the X-direction fine movement mechanism 9 via the amplifier 43, and is also connected to the Y-direction fine movement mechanism 10 via the amplifier 44. A predetermined bias voltage is applied from the power supply circuit 45 to the sample 3 on the table 4.

Next, the operation of the above configuration will be described.

First, the sample 3 is mounted on the table 4. Then, in this state, the X-direction coarse movement mechanism 25 and the Y-direction coarse movement mechanism 26 formed by the micrometer are manually operated to coarsely move the sample 3 along the horizontal plane in the X and Y directions. The desired measurement portion on the surface of the sample 3 is probed 29
To be placed opposite.

Then, the power supply circuit 45 is connected to the sample 3 on the table 4 to apply a predetermined bias voltage. In this state, next, the first coarse movement mechanism 31 and the second coarse movement mechanism 32 of the Z-axis mechanism 6 are manually operated to lower the probe 29.
Of the sample 3 is brought close to the sample 3 on the table 4. In this case, the tip of the probe 29 is brought close to the sample 3 on the table 4 up to a tunnel region where the distance between the tip of the probe 29 and the sample 3 on the table 4 is 2 nm or less and a tunnel current flows. Then, in this state, the control signal from the control unit 33 is supplied to the X-direction fine movement mechanism 9 via the D / A converter 35 and the amplifier 43, and similarly, the control signal from the control unit 33 is changed to D / A.
The Y-direction fine movement mechanism 10 via the A converter 35 and the amplifier 44.
The sample 3 on the table 4 is scanned in the X direction and the Y direction by the X direction fine movement mechanism 9 and the Y direction fine movement mechanism 10.

Further, the tunnel current detected by the probe 29 when the sample 3 on the table 4 is scanned in the X direction and the Y direction is amplified by the amplifier 41, and then the comparison amplifier 3
9 is input. Then, the comparison amplifier 39 compares the reference current output from the reference power source with the detected tunnel current, the error amount is amplified by the comparison amplifier 39, and then input to the control circuit 38. Further, the control circuit 38 outputs a control signal for driving the probe 29 in a direction in which the error between the reference current and the detected tunnel current is set to zero. The control signal is sent to the drive circuit 42.
The voltage is supplied to the Z-axis fine movement mechanism 30 in a state where the voltage is amplified by the Z-axis fine movement mechanism 30, and the Z-axis fine movement mechanism 30 detects the tunnel current flowing between the tip of the probe 29 and the sample 3 on the table 4 in a constant state. The needle 29 is driven in the direction perpendicular to the scanning direction of the table 4. In this case, the control signal supplied from the control circuit 38 to the drive circuit 42 is the A / D converter 34.
After being converted into a digital signal by, the signal is input to the control unit 33 in a state synchronized with the control signals of the X-direction fine movement mechanism 9 and the Y-direction fine movement mechanism 10 for scanning the sample 3 on the table 4 in the X and Y directions. . Then, based on this input signal, the control unit 33 processes the information about the surface shape (concavo-convex state) of the sample 3, and the detected surface shape of the sample 3 is displayed on the CRT or the like of the display unit 37.

Therefore, in the above structure, the table drive mechanism 5
2 in the X and Y directions, which are orthogonal to each other.
A table fine movement mechanism 8 for performing a minute displacement in a dimension and a table coarse movement mechanism 24 for coarsely moving the table 4 in the same direction as the driving direction of the table fine movement mechanism 8 by a displacement amount larger than the displacement amount by the table fine movement mechanism 8 are provided. Therefore, the holding table 4 of the sample 3 can be displaced in two directions orthogonal to each other with a relatively large displacement amount. Therefore, the observation area on the surface of the sample 3 can be significantly enlarged as compared with the conventional case.

Furthermore, each bimorph type piezoelectric element 12a, 12b, 13a, 13 of the X-direction fine movement mechanism 9 and the Y-direction fine movement mechanism 10.
Since b has a structure of supporting both ends, the supporting rigidity of the table 4 can be increased. Therefore, the natural frequency of the table 4 can be increased and the measurement operation of the sample surface can be stably performed.

Further, the bimorph type piezoelectric elements 12a, 12b, 13a, 13b of the X-direction fine movement mechanism 9 and the Y-direction fine movement mechanism 10 respectively.
The two piezoelectric elements A and B constituting the above are bonded to each other via the central electrode 22, and the divided electrodes 18a, 19a, 20a, 21a, 18b and 19 are formed on the outer surfaces of the respective piezoelectric elements A and B.
b, 20b, 21b are arranged side by side, and the electrodes of the bimorph type piezoelectric elements 12a, 12b, 13a, 13b are divided to form the bimorph type piezoelectric elements 12a, 12b, 13a,
By configuring displacement amount amplification means for amplifying the displacement amount of 13b, each bimorph type piezoelectric element 12a, 12b, 1
When a voltage is applied to 3a and 13b, the two piezoelectric elements A and B forming the respective bimorph type piezoelectric elements 12a, 12b, 13a and 13b are provided with one piezoelectric element A at both ends.
Is extended in the lengthwise direction and at the same time, the other piezoelectric element B is deformed in the direction of contracting in the lengthwise direction, and at the inner portions of the both end side deformed portions, the piezoelectric element B is extended in the lengthwise direction and at the same time the piezoelectric element A is extended. By deforming the bimorph type piezoelectric elements 12a, 12b, 13a, 13b in the direction of contracting in the vertical direction, the entire bimorph type piezoelectric elements 12a, 12b, 13a, 13b can be deformed into a substantially bow shape. Therefore, the displacement amount (stroke) of the table 4 in the X and Y directions
Can be made relatively large, so that the scanning region of the holding table 4 can be enlarged when the surface shape of the sample 3 is measured.

Further, since the table 4 can be two-dimensionally minutely displaced in two directions orthogonal to each other along the horizontal plane by the fine movement mechanisms 9 and 10, the fine structure of the surface of the sample 3 can be accurately measured.

Further, since the probe 29 is driven along the vertical direction, the sample holding surface of the table 4 can be arranged along the horizontal plane. Therefore, it is not necessary to firmly fix the sample 3 to the sample holding surface of the table 4 as in the case of driving the probe 29 in the horizontal direction.
It is possible to facilitate handling of the sample 3 mounted on the sample holding surface, and prevent the size, thickness, weight, etc. of the sample 3 mounted on the sample holding surface of the table 4 from being restricted. it can.

Further, since the tilt of the sample can be corrected by the tilt stage 27, when the measurement is performed in a large observation area, the tilt of the sample causes the sample to deviate from the measurement range of the fine movement mechanism in the Z direction during measurement. It can be prevented. Therefore, it is possible to measure a large range even for a sample having an inclination.

The present invention is not limited to the above embodiment. For example, the X-direction fine movement mechanism 9 and the Y-direction fine movement mechanism 1
0 may be configured as shown in FIGS. 9 to 11.

In FIG. 9, reference numeral 51 is the main body of the fine movement mechanism. A holding table 4 for the sample 3 is provided at the center of the fine movement mechanism main body 51, and the table 3 is provided around the table 4 with a predetermined space therebetween.
Substantially rectangular frame-shaped frame bodies 52, 53, 54 stacked in layers are arranged, respectively. Further, on the outer first frame 52, piezoelectric element mounting openings 55a and 55b are formed on a pair of opposing wall surfaces along the X direction (or Y direction) of the table 4, respectively. In these openings 55a and 55b, a pair of bimorph-type piezoelectric elements 56a, which are arranged in parallel on both sides of the table 4 in the X direction (or the Y direction), are spaced apart and face each other.
56b are arranged respectively. In this case, the bimorph type piezoelectric elements 56a and 56b have openings 55 at both ends thereof.
It is mounted between both ends of a and 55b in a erected state to have a structure of supporting both ends. The first frame 52 forms a first support frame that connects the ends of the pair of bimorph piezoelectric elements 56a and 56b.

The bimorph type piezoelectric elements 56a and 56b are formed by bonding two piezoelectric elements A and B, which expand and contract in the lengthwise direction when a voltage is applied, as shown in FIG. Bending displacement is generated by contracting. FIG. 11 shows the electrode structure of the bimorph type piezoelectric elements 56a and 56b.
The arrows of the piezoelectric elements A and B in FIG. 1 indicate the polarization directions.

Further, in the second frame body 53 inside the first frame body 52, the bimorph type piezoelectric elements 56a and 56b are provided at substantially central portions of a pair of opposing wall surfaces along the X direction (or the Y direction) of the table 4.
Protrusions 57a and 57b are formed so as to protrude toward the side. The protrusions 57a and 57b are fixed at substantially central portions in the longitudinal direction of the bimorph type piezoelectric elements 56a and 56b to form a support structure at both ends.

Further, the second frame 53 has a bimorph type piezoelectric element 56.
bimorph type piezoelectric element 58a having the same structure as a, 56b,
58b are arranged in parallel on both sides of the table 4 in the X direction (or Y direction) in a spaced-apart and opposed state. In this case, the bimorph type piezoelectric elements 58a and 58b are mounted at their both ends in a state of being erected between the supporting protrusions 59a and 59a of the second frame 53, thereby forming a both-end supporting structure. Then, the pair of bimorph type piezoelectric elements 58a and 5a are formed by the second frame 52.
A second support frame is formed to connect both ends of 8b.

Further, in the third frame body 54 inside the second frame body 53, bimorph type piezoelectric elements 58a, 58b are provided at substantially central portions of a pair of opposing wall surfaces along the X direction (or Y direction) of the table 4.
Protrusions 60a and 60b are formed so as to protrude toward the side. The central portions of the bimorph type piezoelectric elements 58a and 58b in the longitudinal direction are fixed to the protrusions 60a and 60b.

Further, the bimorph type piezoelectric element 58 is provided on the third frame 54.
bimorph type piezoelectric element 61a having the same structure as a, 58b,
61b are arranged in parallel on both sides of the table 4 in the X direction (or the Y direction) in a spaced-apart and opposed state. In this case, the bimorph type piezoelectric elements 61a and 61b are mounted at their both ends in a state of being erected between the support protrusions 62a and 62b of the third frame 54 to have a both-end support structure. Then, the pair of bimorph type piezoelectric elements 61a, 6a is formed by the third frame 53.
A third support frame is formed to connect both ends of 1b.

Further, on the table 4 inside the third frame 53, a projection portion is provided at a substantially central portion of a pair of opposing wall surfaces along the X direction (or Y direction) so as to project toward the bimorph type piezoelectric elements 61a and 61b. 63a and 63b are formed. The bimorph type piezoelectric element 61 is provided on the protrusions 63a and 63b.
A central portion in the longitudinal direction of a and 61b is fixed.

The fine movement mechanism main body 51 is shown in FIGS. 10 and 1 in a non-operating state in which no voltage is applied to the bimorph type piezoelectric elements 56a, 56b, 58a, 58b, 61a, 61b.
As shown by the solid line in FIG. 1, each bimorph type piezoelectric element 56
a, 56b, 58a, 58b, 61a, 61b are each held in a substantially linear normal state,
In this state, the table 4 is held at the central neutral position.

Further, the fine movement mechanism main body 11 includes the bimorph type piezoelectric elements 56.
When a voltage is applied to a, 56b, 58a, 58b, 61a, 61b, each bimorph type piezoelectric element 56a, 5
The entire 6b, 58a, 58b, 61a, 61b are deformed into a substantially arched shape as shown by the phantom line in FIG. 10 as in the first embodiment. In this case, the X-direction fine movement mechanism 9 includes the bimorph type piezoelectric elements 56a, 56b, 58a, 58b, 61.
Since a and 61b are arranged in parallel along the X direction of the table 4, the outer bimorph type piezoelectric elements 56a,
The second frame body 52 is displaced by x _{1 in} the X direction of the table 4 with respect to the first frame body 51 by the deformation of 56b, and the second frame body 52 is similarly deformed by the deformation of the bimorph type piezoelectric elements 58a, 58b. In contrast, the third frame 53 is the X of the table 4.
Is displaced by x _{2 in the} direction, and the bimorph type piezoelectric element 61a,
By the deformation of 61b, the table 4 is displaced with respect to the third frame body 52 by x _{3 in the} X direction. Therefore, the table 4 is arranged in the X direction of the table 4 with respect to the first frame 51 by x ₁
It is designed to be displaced by + x ₂ + x ₃ .

In addition, the Y-direction fine movement mechanism 10 includes each bimorph type piezoelectric element 5
6a, 56b, 58a, 58b, 61a, 61b are arranged in parallel along the Y direction of the table 4, respectively,
Due to the deformation of the outer bimorph type piezoelectric elements 56a and 56b, the second frame body 52 is displaced with respect to the first frame body 51 in the Y direction of the table 4 by y ₁ , and similarly, the bimorph type piezoelectric elements 58a and 58b are deformed. Due to the deformation, the third frame 53 is displaced by y _{2 in} the Y direction of the table 4 with respect to the _second frame 52, and due to the deformation of the bimorph type piezoelectric elements 61a and 61b, the third frame 53 is displaced with respect to the third frame 52. Table 4 is y _{3 in} Y direction
Only displaced. Therefore, the table 4 includes the first frame 5
1 is displaced by y ₁ + y ₂ + y _{3 in} the Y direction of the table 4.

Therefore, in the structure described above, the bimorph type piezoelectric elements 56 of the X-direction fine movement mechanism 9 and the Y-direction fine movement mechanism 10 are arranged.
a, 56b, 58a, 58b, 61a, 61b are arranged in three stages along the X direction and the Y direction of the table 4, respectively, and the bimorph type piezoelectric elements 56a, 56b, 58a,
At the time of deformation of 58b, 61a, 61b, the bimorph type piezoelectric elements 56a, 56b, 58a, 58b, 61a at each stage are deformed.
Since the table 4 is displaced while sequentially stacking the displacement amounts of the table 4 in the X and Y directions due to the deformation of 61b, it is possible to increase the scanning area of the holding table 4 when measuring the surface shape of the sample 3. Can be planned.

Further, in the embodiment shown in FIGS. 9 to 11, the bimorph type piezoelectric elements 56a, 56b, 58a, 58b, 61a, 61 of the X-direction fine movement mechanism 9 and the Y-direction fine movement mechanism 10 are used.
b are arranged in parallel in three stages along the X direction and the Y direction of the table 4, and the bimorph type piezoelectric elements 56a, 56
When the b, 58a, 58b, 61a, 61b are deformed, the bimorph type piezoelectric elements 56a, 56b, 58a, 58 of the respective stages are formed.
b, 61a, and 61b are deformed, the displacement amounts of the table 4 in the X direction and the Y direction are sequentially stacked.
However, the number of stacked layers of the bimorph type piezoelectric element may be further increased, and in this case, the scanning region of the table 4 in the X direction and the Y direction can be further expanded.

Further, in the above-described embodiment, the X-direction fine movement mechanism 9 and the Y-direction fine movement mechanism 10 are separately provided, and these are stacked vertically in two stages. However, as shown in FIG. 12, the X-direction fine movement mechanism is shown. 9 and the Y direction fine movement mechanism 10 are incorporated in a single fine movement mechanism main body 71, and the fine movement mechanism main body 71 causes the table 4 to be orthogonal to each other in two directions (X direction and Y direction).
It may be configured to scan two-dimensionally in the direction). In this case, the bimorph type piezoelectric elements 72a, 72b, 73a, 73b, 74a, 74 of the respective stages forming the X-direction fine movement mechanism 9 are formed.
b are arranged in parallel along the X direction of the table 4 and each stage of the bimorph type piezoelectric elements 75a, 75b, 76a, 76b, 77a, 7 forming the Y direction fine movement mechanism 10.
7b are arranged in parallel along the Y direction of the table 4. When the fine movement mechanism main body 71 is operating, the X direction fine movement mechanism 9
Forming bimorph type piezoelectric elements 72a, 72
The displacement amounts x ₁ , x ₂ , x _{3 in the} X direction due to the deformation of b, 73a, 73b, 74a, 74b are the operation arms 78, 7 respectively.
The bimorph type piezoelectric elements 75a, 75b, 76a, 76b, 7 at the respective stages forming the Y-direction fine movement mechanism 10 while being sequentially laminated via 9 and 80 and transmitted to the table 4.
Displacement amounts y ₁ and y in the Y direction due to deformation of 7a and 77b
₂ , ₂ and y ₃ are sequentially stacked via the operation arms 81, 82 and 83 and transmitted to the table 4.

Further, the fine movement mechanism 30 of the Z-axis mechanism 6 may have the same configuration as the X-direction fine movement mechanism 9 and the Y-direction fine movement mechanism 10 of the above-described embodiment. In this case, the amount of vertical movement of the probe 29 can be increased.

Furthermore, it goes without saying that various modifications can be made without departing from the scope of the present invention.

EFFECTS OF THE INVENTION According to the present invention, a table fine movement mechanism for finely displacing the table two-dimensionally in two directions orthogonal to each other along a horizontal plane in accordance with the displacement operation of the bimorph type piezoelectric element, and a driving direction of the table fine movement mechanism, Since the table drive mechanism is provided with the table coarse movement mechanism that coarsely moves the table in the same direction by a displacement amount larger than the displacement amount by the table fine movement mechanism, the observation area of the sample surface can be expanded and It is possible to measure a fine structure with high accuracy and reduce restrictions such as the size of the sample.

Furthermore, the bimorph type piezoelectric element is provided with a fixed part to the fixed part side and a fixed part to the table side in the central part of the bimorph type piezoelectric element, and the bimorph type piezoelectric element has a structure to support both ends, thus holding the sample. The supporting rigidity of the rotating table can be increased, and the measurement operation of the sample surface can be stably performed.

Further, since the displacement amount amplifying means for amplifying the displacement amount of the bimorph type piezoelectric element is provided by dividing the electrode of the bimorph type piezoelectric element, it is possible to enlarge the displacement amount by the table fine movement mechanism and enlarge the observation area of the sample surface. You can

[Brief description of drawings]

1 to 8 show an embodiment of the present invention.
FIG. 1 is a side view showing a schematic configuration of the entire scanning tunneling microscope apparatus, FIG. 2 is a perspective view showing a fine movement mechanism, and FIG. 3 is a side view for explaining a deforming operation of a bimorph piezoelectric element.
FIG. 4 is a plan view showing a state in which electrodes are arranged in parallel on the outer surface of the piezoelectric element,
FIG. 5 is a schematic configuration diagram showing a wiring state of each electrode of the bimorph piezoelectric element, FIG. 6 is a schematic configuration diagram showing a control circuit, and FIG.
FIG. 8 is a perspective view of a tilt stage, FIG. 8 is a side view showing a part of the tilt stage in a cutaway manner, FIGS. 9 to 11 show another embodiment of the present invention, and FIG. FIG. 10 is a plan view showing the mechanism, FIG. 10 is a schematic configuration diagram for explaining a deforming operation of the bimorph piezoelectric element, and FIG. 11 is a schematic configuration diagram of essential parts showing a state in which a part of FIG. 10 is enlarged, FIG. 1 is a plan view of a main portion showing still another embodiment of the present invention,
FIG. 3 is a perspective view showing a tripod, and FIG. 14 is a perspective view showing a tube scanner. 3 ... Sample, 4 ... Table, 5 ... Table drive mechanism, 6 ... Z-axis mechanism, 8 ... Fine movement mechanism, 9 ... X-direction fine movement mechanism, 10 ... Y-direction fine movement mechanism, 12a, 12b, 1
3a, 13b ... Bimorph type piezoelectric elements, 18a, 18
b, 19a, 19b, 20a, 20b, 21a, 21b
...... Split electrodes, 24 ...... Coarse movement mechanism, 25 ...... X direction coarse movement mechanism, 26 ...... Y direction fine movement mechanism, 29 ...... Probe.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Fumihiko Ishida Inventor Fumihiko Ishida 8 Shinsita-cho, Isogo-ku, Yokohama-shi, Kanagawa Stock Production Company, Toshiba Institute of Industrial Technology (72) Inventor Masakazu Hayashi 8 Shinsita-cho, Isogo-ku, Yokohama, Kanagawa In the production company Toshiba Production Engineering Laboratory (72) Inventor Tamiki Yasunaga 8 Shinsita-cho, Isogo-ku, Yokohama-shi, Kanagawa Stock Company Inside the Toshiba Production Engineering Laboratory (72) Inventor Junzo Uchida 336 Tatehara, Fuji City, Shizuoka Co., Ltd. Shigeo Arai, Examiner, Toshiba Fuji Plant (56) References JP-A-63-281002 (JP, A) JP-A-62-266882 (JP, A) JP-A-61-285776 (JP, A) Actual development Sho-62 -174362 (JP, U)

Claims (1)

[Claims] 1. A table drive mechanism for two-dimensionally scanning a table holding a sample in two directions orthogonal to each other, and a probe for detecting a minute current arranged facing the sample on the table in a scanning direction of the table. On the other hand, a probe drive mechanism for driving in the vertical direction is provided, and the probe is brought close to the sample on the table to such an extent that both electron clouds overlap each other,
The surface shape of the sample on the table is driven by driving the probe in a direction perpendicular to the scanning direction of the table while the tunnel current flowing when a potential difference is applied between the two is kept constant. In a scanning tunneling microscope apparatus for measuring the temperature, a table fine movement mechanism for finely displacing the table two-dimensionally in two directions orthogonal to each other along a horizontal plane in accordance with a displacement operation of a bimorph type piezoelectric element, and a driving direction of the table fine movement mechanism. And a table coarse movement mechanism that coarsely moves the table in the same direction as the table fine movement mechanism by a displacement amount larger than the displacement amount by the table fine movement mechanism, and the table fine movement mechanism includes both ends of the bimorph type piezoelectric element. Is fixed to the table coarse movement mechanism side, and the table is provided at a substantially central portion of the bimorph type piezoelectric element. And a polarization direction at predetermined portions at a plurality of positions between the both ends of the bimorph type piezoelectric element is determined in advance, and further, the polarization direction of the bimorph type piezoelectric element corresponding to the predetermined portion is provided. Displacement amount amplification means for amplifying the displacement amount of the bimorph type piezoelectric element by dividing the electrode and applying a voltage to the electrode to deform the portion between the both ends of the bimorph type piezoelectric element into a substantially arc shape is provided. A scanning tunneling microscope device characterized in that