JPH04557B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an X-Y-Z movement mechanism used, for example, to finely move a probe of a scanning tunneling microscope.

[Conventional technology]

Scanning tunneling microscope (hereinafter referred to as STM)
As is well known, the probe is used to scan the material surface while keeping the tunneling current constant to obtain information on the material surface shape such as the atomic arrangement structure. ) below the level
Since it is necessary to perform fine movement control in the three axial directions of -Y-Z, a piezoelectric actuator that can obtain minute expansion and contraction displacements has conventionally been used as a probe movement mechanism. Figure 5 shows a conventional moving mechanism, which is schematically shown on page 825 of the paper ``Scanning Tunneling Microscope'' published in the publication ``Bulletin of the Japan Institute of Metals, Vol. 25, No. 10.'' 1 is the base, 2
is a piezoelectric actuator that expands and contracts in the X-axis direction, 3 is a piezoelectric actuator that expands and contracts in the Y-axis direction, and 4 is a Z-axis
This is a laminated piezoelectric actuator that expands and contracts in the axial direction, and 1 to 4 constitute an XYZ movement mechanism. 5 is a probe, and 6 is a sample.

By applying positive and negative drive voltages, the piezoelectric actuators 2 to 4 can expand and contract by an amount corresponding to the axial length and the drive voltage, so the probe 5 can be displaced three-dimensionally at the nanometer (nm) level. can.

[Problem that the invention seeks to solve]

In order to increase the accuracy of the material surface shape information obtained by three-dimensional scanning of the material surface, it is important to eliminate the effects of mechanical and acoustic vibrations applied to the probe 5 and the ambient temperature. To do this, it is necessary to perform three-dimensional displacement at high speed. The upper limit for speeding up is determined by the resonance frequency of the X-Y-Z movement mechanism, and increasing the speed requires increasing the rigidity. Furthermore, if the layer thickness is increased to increase rigidity, the device becomes larger and the drive voltage increases accordingly, which increases the cost of the drive power source and increases the electrical noise exerted on peripheral devices. It was hot.

This invention was made to solve the above problem, and provides an X-Y-Z movement mechanism that uses a highly rigid cylindrical piezoelectric actuator and can perform high-speed displacement compared to the conventional one. With the goal.

[Means to solve the problem]

In order to achieve the above object, the present invention provides an insulating fixing device having an X-axis direction through-hole, a Y-axis direction through-hole, and a Z-axis direction through-hole, and defining a space in which each of the through-holes opens together. The block body has an X-axis direction hole, a Y-axis direction hole, and a Z-axis direction hole, and each opening coaxially faces the X-axis direction through-hole, the Y-axis direction through-hole, and the Z-axis direction through-hole. an insulating moving block body disposed in the cavity; an end protruding from the hole gripped by a first gripping mechanism that is inserted into the hole and engages with the hole so as to move back and forth in the axial direction; The movable block has a cylindrical piezoelectric actuator held by a second gripping mechanism held by the fixed block body such that the piezoelectric actuator passes through the through hole coaxially with the hole and is movable in the axial direction. The structure includes a driven body holding mechanism for attaching the driven body to the body.

[Effect]

This invention uses a cylindrical piezoelectric actuator whose both ends are gripped by a gripping mechanism.
The rigidity is high, the resonance frequency is increased, and the drive voltage required to obtain the desired displacement is also low. Furthermore, since it uses a gripping mechanism, it can be used under ultra-high vacuum.

〔Example〕

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

In FIGS. 1 to 3, 10 indicates the entire X-Y-Z moving mechanism. Reference numeral 11 denotes an insulating fixed block body, which includes an upper wall 12, a side wall 13, and a rear wall 14.
It has a shape having a cubic space 15 surrounded by , and one end is inserted and fixed into a fitting part 17 for installation formed at a predetermined position in the height direction of a corner 16 formed by the side wall 13 and the rear wall 14. It is connected to, for example, a vertical movement mechanism (not shown) (referred to as a coarse movement mechanism and used for initial setting of the probe) via a horizontal support 18 . 19 is a mounting screw. The above-mentioned space is provided vertically on the top wall 12 (in the Z-axis direction), horizontally on the side wall 13 (in the Y-axis direction), and horizontally on the rear wall 14 (in the X-axis direction). A through hole 20 communicating with the location 15 is formed. A cylindrical portion 21 of a T-shaped pressurizing body 23 having a mounting flange portion 22 at one end of a cylindrical portion 21 on an outer peripheral threaded surface is concentrically and loosely fitted into the through hole 20 . The flange portion 22 is in contact with the outer surface of the fixed block body 11 and is fixed with screws 24. A pressure ring 28 is inserted into the cylindrical portion 21 of the pressure body 23,
A cylindrical pressure nut 25 is externally fitted and screwed onto the outer surface, and the lower end of the pressure nut 25 forms a fitting portion 26 having a conical inner surface. This fitting part 2
At 6, a collect chuck 27 having a conical fitting portion on the outer surface is engaged by fitting the fitting portion into the fitting portion 26, and the collect chuck 27 and the cylindrical portion 2
1, a ring portion of a pressure ring 28 is interposed between the pressure ring 28 and the pressure ring 28. This collector chuck 27 is electrically conductive and grips one end of a cylindrical piezoelectric actuator 30, which will be described later, and 23 to 28 constitute a first gripping mechanism. Reference numeral 40 denotes a moving block body, which has three bottomed cylinder parts (square cylinder parts) 42 extending from a base 41 in the Z-axis direction, the Y-axis direction, and the X-axis direction. The opening of the section 42, the opening of the cylinder part 42 in the Y-axis direction, and the opening of the cylinder part 42 in the It is located in The hole 43 of the cylindrical portion 42 is a cylindrical hole with a bottom, and an annular fitting recess 44 whose outer surface is a conical surface is formed at the bottom, and a threaded portion is formed on the inner peripheral surface near the opening. A conductive collector chuck 45 that grips the other end of the piezoelectric actuator 30 is fitted into the fitting recess 44, and the collector chuck 45 is pressed via a pressure ring 46. A pressure nut 47 is screwed into the threaded portion. That is, the moving block 40 is supported by the fixed block 11 via three piezoelectric actuators 30 that are orthogonal to each other. 44-4
7 constitutes a second gripping mechanism. The base 41 of the moving block body 40 and the Z continuous from the base 41
The outer corner of the cylindrical portion in the axial direction is formed as a pedestal surface 48 that forms an oblique angle of 45 degrees with respect to the X-axis and Y-axis directions, and the axis of the hole 43 in the X-axis direction and the hole in the Y-axis direction A vertical groove 49 is located at the intersection of the axis of 43.
is formed, and the probe 50 is fixed by aligning the probe 50 along the groove 49 and fixing a needle fixing plate 51 in contact with the base surface 48. 52 is a fixing screw. As shown in FIG. 4, the piezoelectric actuator 30 has a cylindrical shape, and includes an inner electrode (positive electrode) 31 with one end exposed at one end of the outer peripheral surface, and an inner electrode (positive electrode) 31 separated from the electrode 31 by a predetermined insulation distance. It has an outer surface electrode (negative electrode) 32 provided on the other part of the outer peripheral surface, and as described above, one end is held by the collect chuck 27 and the other end is held by the collect chuck 45.

In this configuration, the piezoelectric actuator 30
When a positive and negative driving voltage is applied between the electrodes 31 and 32, the movable block 40 and therefore the probe 50 are displaced by an amount corresponding to the magnitude of the driving voltage.
- Three-dimensional displacement in the Y-Z axis direction is possible.

In this embodiment, a cylindrical piezoelectric actuator 30 is used as the piezoelectric actuator, and since the cylindrical piezoelectric actuator 30 can increase the rigidity about twice as much as the laminated piezoelectric actuator, the above-mentioned resonance This allows the probe 50 to be displaced at high speed.

Further, the distance between the electrodes of the piezoelectric actuator 30 is small because of the wall thickness, and therefore the driving voltage can be set to a low voltage.

Furthermore, the piezoelectric actuator is usually held by bonding it to a holding body with adhesive;
In this embodiment, both ends of the piezoelectric actuator 30 are gripped by a first gripping mechanism having a collect chuck 27 and a second gripping mechanism having a collect chuck 45, so that the moving mechanism of the embodiment can also be used under ultra-high vacuum (10 ^-8 _TOrr or less). In other words, when used in an ultra-high vacuum, it is necessary to bake to a temperature of 200 degrees or higher, and currently commercially available adhesives lose adhesive strength at about 150 degrees, but in the case of the collect chuck method of this example. Even if baked at temperatures above 200 degrees, the gripping force will not decrease.

Further, since the piezoelectric actuator 30 is configured to be gripped at both ends by two gripping mechanisms, and these are integrated into a unit, there is an advantage that the piezoelectric actuator 30 can be easily attached and removed.

〔Effect of the invention〕

As explained above, this invention uses a highly rigid cylindrical piezoelectric actuator as a drive element, which prevents resonance at low frequencies, making it possible to move at higher speeds than in the past. In addition, the desired displacement can be obtained with a low drive voltage, so the above effects can be obtained without increasing the cost of the drive power supply or increasing electrical noise. Since it is carried out in a vacuum, it can be used even under ultra-high vacuum, and it has the advantage of being easy to install and remove.

[Brief explanation of drawings]

Fig. 1 is a side view showing an embodiment of the invention, Fig. 2 is a side view showing an embodiment of the present invention;
The figure is a plan view of the above embodiment, FIG. 3 is a sectional view taken along the - arrow in FIG. 1, FIG. 4 is a sectional view of the piezoelectric actuator in the above embodiment, and FIG. FIG. 11...Fixed block body, 20...Through hole, 2
7...Collection chuck of first gripping mechanism, 30
... Cylindrical piezoelectric actuator, 40 ... Moving block body, 45 ... Collection chuck of second gripping mechanism, 50 ... Probe.

Claims (1)

[Scope of Claims] 1. An insulating fixed block body having an X-axis direction through-hole, a Y-axis direction through-hole, and a Z-axis direction through-hole and defining a space in which each of the through-holes opens together; It has an X-axis direction hole, a Y-axis direction hole, and a Z-axis direction hole, and each opening is coaxially opposed to the above-mentioned X-axis direction through-hole, Y-axis direction through-hole, and Z-axis direction through-hole. An insulating moving block body disposed within the hole is gripped by a first gripping mechanism that is inserted into the hole and engaged with the hole so as to be movable in the axial direction, and the end that protrudes from the inside of the hole is attached to the hole. A cylindrical piezoelectric actuator is gripped by a second gripping mechanism held by the fixed block body so as to be able to advance and retreat in the axial direction through the through hole coaxial with the movable block body. An X-Y-Z moving mechanism characterized by being provided with a driven body holding mechanism for attaching a driven body. 2. A patent claim characterized in that the first gripping mechanism comprises an annular fitting recess having a conical outer surface formed at the bottom of the hole, and a collection chuck having a conical outer surface inscribed in the conical outer surface. The X-Y-Z movement mechanism according to item 1. 3. The second gripping mechanism includes a pressurizing body having a cylindrical portion fixed to the fixed block body and extending into the through hole, which is externally fitted and screwed onto the pressurizing body, and the inner surface of one end is formed into a conical fitting portion. Claim 1, characterized in that the invention comprises a pressurizing nut, a collect chuck that fits into the conical fitting portion, and a pressurizing ring interposed between the collect chuck and the cylindrical portion. X-Y-Z
Moving mechanism. 4. The driven object is a probe of a scanning tunneling microscope, and the driven object holding mechanism consists of a groove formed in the Z-axis direction at a position where the axes of the three holes intersect, and a fixing plate that closes the groove, The X-Y-Z moving mechanism according to claim 1, 2, or 3, wherein the upper end of the probe is held under pressure by the groove wall of the groove and the fixing plate. . 5. Claim 1, 2, or 3, characterized in that one end of the inner electrode of the piezoelectric actuator extends to one end of the outer surface.
The X-Y-Z movement mechanism according to item 4 or item 4.