JPH0635364Y2 - Micro positioning mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a micropositioning mechanism for performing micropositioning between a detection unit and a sample in the field of analytical instruments and scanning tunneling microscopes.

[Outline of device]

Separate the inside of the vacuum chamber (vacuum side) and the atmosphere side via the bellows, and provide a differential screw mechanism and a stepping motor or an inchworm mechanism as a drive source on the atmosphere side, and move the shaft provided in the center. The sample piece installed in the vacuum environment is moved forward or backward by the sample provided at the opposite position of the detection probe attached to the tip of the sample piece through the fine movement mechanism composed of the piezoelectric element. It is a mechanism for finely adjusting the position, and is an industrially useful second positioning mechanism.

[Conventional technology]

A bias voltage is applied between the sample surface and the tip of the detection probe to detect a tunnel current flowing between the two, and the space between the sample surface and the tip of the detection probe is controlled so that the tunnel current becomes constant, or Scanning tunneling microscope that detects the tunnel current value, monitors the change in the tunnel current value, and observes the sample surface with resolution up to the atomic structure.It operates along the x and y directions of the sample surface and along the unevenness of the sample surface. It is necessary to have a mechanism for aligning the detection probe fixed to the three-dimensional fine movement mechanism composed of a piezoelectric element to the region (several nanometers 10 ^-9 m) where the tunnel current flows between the detection probe tip and the sample surface. is there. Conventionally, as shown in FIG. 6, the rotational movement of the stepping motor 101, which is a drive source, is changed by the clutch 102.
To the differential screw mechanism 103, and the detection probe 106 attached to the tip of the piezoelectric element fine movement mechanism 105 attached to the tip of the top 104 in a meshed relationship with the differential screw 103 There is a mechanism for aligning a sample 107.

[Problems to be solved by the device]

In the above mechanism, the stepping motor is divided and the scale of the differential screw mechanism is used to achieve sufficient positioning in the tunnel area as a scanning tunneling microscope. Lubricant required. Although there is no problem in using such a mechanism in the atmosphere, when observing the active sample surface, prepare the sample in a vacuum environment where it is difficult to form an oxide film on the active sample surface. Then, it is necessary to continue the observation using a scanning tunneling microscope in a vacuum environment. Therefore, a lubricant that pollutes the vacuum environment cannot be used. Also, in the non-lubricated state, the friction of the sliding part becomes large and the movement becomes awkward, and the heat treatment (baking) of water and gas to increase the degree of vacuum causes the sliding part to seize and become immobile. there were.

[Means for Solving the Problems]

This invention, which solves the above problems, is divided into a vacuum side and an atmosphere side through a bellows, and a differential screw mechanism and a stepping motor or an inchworm mechanism as a driving source are provided on the atmosphere side, and are provided in the center. By moving the axis
The top part installed in the vacuum environment is moved forward or backward, and the detection probe attached to the tip of the top part via the piezoelectric element fine movement mechanism is made minute with respect to the sample provided at the opposite position. I tried to align them. In addition, in order to reduce sliding in a vacuum environment, the top portion is brought into contact with the guide portion at three points, and a lubricating film including two base layers having a gold coating as the uppermost layer is formed.

[Action]

With the above configuration, since the differential screw mechanism that requires the most lubricant can be configured on the atmosphere side separated from the vacuum environment, a normal lubricant can be used. Also, the top part provided in the vacuum environment has a shape that reduces sliding, and by covering it with a lubricating film that does not contaminate the vacuum environment, the alignment required for the scanning tunnel microscope is easy even in the vacuum environment. You can do it.

〔Example〕

The present embodiment relates to a minute positioning mechanism for second positioning between a detection probe of a scanning tunneling microscope and a sample, which will be described below with reference to the drawings.

(First Embodiment) FIGS. 1 and 2 are schematic views of an external positioning mechanism and an internal positioning mechanism of a micro positioning mechanism of the present invention.
The configuration of each will be described.

First, the external positioning mechanism will be described.

First, in the external positioning mechanism, a through hole having a step portion 3a is formed in the main flange 3 that divides the atmosphere side and the vacuum side, and the mini flange A4 is welded and fixed to the step portion 3a. A bellows 6 for separating the vacuum side and the atmosphere side is provided on a mini flange B5 which is fixed to the mini flange A4 with screws or the like, and a rod body 7 penetrating the mini flanges A and B, the main flange 3 and the bellows 6 is a bellows 6. The rod 7 is welded and fixed to one of the rings 6a at both ends. A columnar portion having a rounded portion 8 formed at the tip is formed at one end of the rod body 7 on the vacuum side, and a hooking jig having a claw 9a is attached to the columnar portion.

The clutch casing is provided on the atmosphere side at the other end of the rod body.
A stepping motor 15 fixed to 16a is provided, and a clutch 16 is connected to the output shaft of this motor. The clutch 16 is composed of a rotary plate 16b having a rotation transmission rod 16a and a sliding plate 16c through which the transmission rod penetrates, the output shaft of the motor is connected to the rotation plate 16b, and rotation of the rotation plate is prevented. While rotating the sliding plate 16c via the transmission rod 16d, the sliding plate 16c
c can slide in the axial direction using the transmission rod as a guide. Here, the through hole provided in the sliding plate 16c is the rotation transmission rod 1
The hole diameter is larger than the diameter of 6d. Therefore, when the rotation transmission rod 16d fixed to the rotating plate 16b by the stepping motor 15 rotates, the diameter of the through hole of the sliding plate 16c is larger than that of the rotation transmitting rod 16d, so the rotation transmitting rod 16d contacts the side surface of the through hole. Until then, the motion of the rotation transmission rod 16d by the stepping motor 15 is not transmitted to the sliding plate 16c. In the present invention, the term clutch is used in this sense.

Then, the first screw 10a is fixed to the sliding plate, and the second screw 10b is fixed to the other end side of the first screw. These screws rotate together with the sliding plate, The second screw constitutes the differential screw mechanism 10. For the first screw, for example, M1
The second screw is 0, pitch 0.55, for example, M6, pitch 0.5.

FIG. 7 shows an outline of the differential screw mechanism. According to this figure,
The configuration will be described. There is a male screw part 201, and this male screw part 201
Is composed of a large-diameter screw portion 202 and a small-diameter screw portion 203 having different screw pitches. The large-diameter screw portion 202 is engaged with the female screw member 204, while the small-diameter screw portion 203 is engaged with the female screw of the block 205. And block 205
Is in the housing 206 fixed to the female screw member 204,
Moreover, by the spring member 207 provided on the casing 206,
The block 205 cannot rotate inside the casing 206, and is pressed against the inner wall portion of the casing 206 by pressure.

Next, the operation will be described. Here, the screws are right-hand screws. The pitch of the large-diameter screw portion 202 is P0.55, the pitch of the small-diameter screw portion 203 is P0.5, the large-diameter screw portion 202 side is the rear, and the small-diameter screw portion 203 side is the front.

First, when the male screw portion 201 is rotated once to the right, the large diameter screw portion 202
Would advance 0.55 forward with respect to the internally threaded member 204. As a result, the block 205 also moves forward 0.55, but since the block 205 is also restricted in rotation, the small diameter screw portion 203
It will be pulled by and will move backward by 0.5 for the pitch of the small diameter screw portion 203. As a result, the block 205 has a male thread 2
By rotating 01 to the right one time, the difference of each screw pitch (0.55
-0.5 = 0.05) You can move forward. As a matter of course, if the male screw is rotated one turn to the left, the block 205 will move backward by 0.05. With such a screw mechanism, the scale of operation can be reduced without reducing the screw pitch.

A linear bush 12 serving as a guide for the rod body 7 is incorporated in the gutter body 11 fixed to the main flange 3 to prevent the rod body 7 from swinging. In addition, the body
A slide cylinder 13 for sliding the outside of 11 to roughly move the rod body 7 directly connected to the differential screw mechanism 10.
There is. Further, there is a degree determining ring 14 which is screwed to the outside of the shell 11 and controls the movement amount of the slide cylinder 13. Further, a stepping motor 15 which is a drive source for driving the differential screw mechanism 10 has a structure in which a clutch 16 is connected.

Next, the internal positioning mechanism will be described with reference to FIG. There is a top 21 that transmits the movement of the external positioning mechanism 1 and slides in the hole of the main body 20. The top 21 has a shape as shown in FIG. 3, and a central groove 32 is provided in the center of the cylindrical member that slides in the hole of the main body 20, and three sliding portions are provided at both ends of the central groove 32. A dividing groove 33 for dividing is provided to reduce the sliding area. Further, in order to reduce friction of the sliding portion, a vacuum lubricating film is formed in the sliding portion. For example, as a vacuum lubrication film, after cleaning the top 21 with an organic solvent, an acid, and an alkali, it is set in a jig provided in an ion plating apparatus called an active reaction vapor deposition method, and up to 5 × 10 ^-5 Torr A vacuum plasma was formed by heating and evaporating titanium with an electron beam to form a discharge plasma by an ion plating mechanism provided, and a titanium nitride film was formed on the set frame 21 at a film forming rate of about 0.05 μm / min to about 1 μm. Micron formed. Then, zirconium is evaporated by an electron beam evaporation device separately provided in the same device, and ion plating is performed in an atmosphere with a nitrogen partial pressure of 5 × 10 ⁻⁴ Torr to make zirconium nitride at a film forming rate of about 0.01 μm / min. 0.1 micron was formed. Further, thereafter, gold was evaporated by another electron beam evaporation apparatus to form a gold coating of about 0.05 μm. Further, the tail portion 34 of the top 21 has a protruding shape so as to be caught by the hooking jig 9 of the external positioning mechanism 1. On the side opposite to the tail portion 34, a voltage is applied between the electrodes in order to slightly move the detection probe 27 in the xy direction and the vertical direction z with respect to the sample at the position facing the detection probe 27. The piezoelectric element fine-movement mechanism 26 that is slightly displaced is fixed. For example, a piezoelectric element fine movement mechanism in which a single cylindrical piezoelectric element body is composed of electrodes that operate in the xy and z directions is used. Further, at the tip of the piezoelectric element fine movement mechanism 26, an insulating board 35 and a probe fixing board are provided.
36 is fixed. Then, the probe seat 37 to which the detection probe 27 is fixed is fixed to the probe fixing plate 36 with screws. To fix the detection probe 27 and the probe seat 37, caulking or the like is used.

Further, there is a clamp block 22 for clamping after the movement of the top 21 is completed, and the clamping force is generated by a leaf spring 24 fixed via a holding plate 23. In order to weaken the clamping force when the top 21 is slid, two laminated piezoelectric element bodies 25 for lifting the pressing plate 23 are incorporated in the left and right.

Further, there is a sample 29 fixed to a sample table 28 at a position opposite to the detection probe 27. The sample table 28 is fixed to the main body 20 by a bayonet spring, and is easily attached and detached.

The main body 20 is fixed to the pedestal 31.

FIG. 4 shows an STM tunnel unit using the external positioning mechanism 1 and the internal positioning mechanism 2 described above. On the vacuum side with the main flange 3 as a boundary, an arm 3b is provided so as to project from the main flange, and a vibration isolation table 42 having a conical spring 41 is suspended by a tension spring 40. The positioning mechanism 2 is fixed. That is,
The internal positioning mechanism has a structure held by a two-stage spring system including a tension spring 40 and a conical spring 41. On the atmosphere side, the external positioning mechanism 1 and the two current introduction flanges 43 are provided on the left and right sides, the straight line introduction machine 44 for the vibration isolation table for operating the clamp mechanism for clamping the vibration isolation table 42, and the sample. Rotation introduction machine for moving the sample table that moves the sample table moving mechanism consisting of a cam and push rod to move the table 28.
It consists of two 45s.

Next, the operation of this mechanism will be described.

(1) Vibration isolation table Operates the DC induction machine 44 for clamps
Clamp 42.

(2) The indexing ring 14 is moved to slide the slide cylinder 13 in the direction of the main flange 3 until the tip rounded portion 8 of the rod 7 contacts the tail portion 34 of the top 21. A difference between the force due to the pressure difference between the vacuum side and the atmosphere side and the bellows spring force is generated. The force due to the pressure difference works to move the rod 7 to the vacuum side, and the spring force due to the bellows works to move the rod 7 to the atmosphere side. Here, if the bellows spring force is smaller than the force due to the pressure difference, the rod body 7 is always moved to the vacuum side, and the slide cylinder 13 connected to the rod body 7 via the differential screw mechanism 10 is also in the main flange 3 direction. To move to. Determining ring to determine the amount of movement
14 is used. In addition, a tension spring is attached between the slide cylinder 13 and the saw body 11 so that the slide cylinder 13 becomes the main flange 3
By moving the bellows in the direction, the bellows force can be used without any problem even when the bellows force becomes larger than the force due to the pressure difference (for example, the entire device is in the same pressure state such as atmospheric pressure).

(3) A voltage is applied to the laminated piezoelectric body 25 to extend the laminated piezoelectric body 25 and lift the plate 23 to weaken the clamping force applied to the top 21 via the clamp block 22.

(4) Move the deciding ring 14 to move the slide cylinder 13
To move the top 21 toward the main flange 3 direction,
The distance between the detection probe 27 and the sample 29 is several mm (for example, 0.5 to 1.5 mm)
The slide cylinder 13 is fixed with screws by aligning the slide cylinder 13 as viewed from the peep hole 30. When viewed from the peep hole 30, it is performed using a microscope having a long focal length fixed to a vacuum chamber.

(5) Keep the axial movement of the piezoelectric element fine movement mechanism 26 in a follow-up state (feedback control), operate the stepping motor 15, and position the detection probe 27 with respect to the sample 29 up to the tunnel region (several nanometers). To match.

(6) The voltage to the laminated piezoelectric body 25 is cut off and the top 21 is clamped.

(7) The stepping motor 15 or the slide cylinder 13 is moved to move the rod body 7 so that the protrusion of the tail portion 34 of the top 21 is located at approximately the middle position of the play portion of the hooking jig, and the slide cylinder 13 is screwed. Fix it.

(8) The straightening machine for the anti-vibration table clamp is operated to release the clamp of the anti-vibration table 42.

As a result, the vibration transmitted through the flange 3 is damped by the vibration isolation table 42, so that the previously performed alignment does not change due to the vibration.

As described above, the scanning tunnel microscope can be observed. Next, a procedure for returning to the original state will be described.

(10) Vibration isolation table Actuating the straight line introduction machine 44 for clamps
Clamp 42.

(11) The stepping motor 15 or the slide cylinder 13 is moved and slid until the protrusion of the tail portion 34 of the top 21 and the pulling jig 9 come into contact with each other.

(12) A voltage is applied to the laminated piezoelectric body 25 to weaken the clamping force on the top 21.

(13) Further, the slide cylinder 13 is moved to move the detection probe 27 away from the sample 29.

(14) The voltage to the laminated piezoelectric body 25 is cut off to clamp the top 21.

The above is a series of operations, and the device manufactured by such a configuration is the STM tunnel unit as the detection probe 27 and the sample 2.
It was confirmed that the alignment of 9 was possible without problems, and the atomic image of highly oriented pyrolytic graphite (HOPG) was observed, and that it had sufficient performance.

(Second Embodiment) FIG. 5 is a schematic view of an external positioning mechanism of the second embodiment. In this embodiment, a stepping motor 15 is used as a mechanism for moving the rod body 7 of the first embodiment.
In contrast to the differential screw mechanism 10 using the drive source as the drive source, the inchworm mechanism 51 that operates like a worm is used. FIG. 8 shows a first half operation diagram of the inch worm mechanism 51, and FIG. 9 shows a second half operation diagram of the inch worm mechanism 51. 8th
The inch worm mechanism 51 will be described with reference to FIGS. There is a rod body 302 in which a piezoelectric body (usually a laminated piezoelectric body) 301 that can expand and contract by a voltage is incorporated, and the rod body 302 is a rod body in which piezoelectric bodies 303 and 305 having the same structure are incorporated.
It is supported by 304, 306 and supports 307, 308 that serve as guides. The rods 304 and 306 and the supports 307 and 308 are fixed to the casing 309.

Next, the operation will be described.

step1 The piezoelectric body 305 is contracted to separate the contact between the rod body 306 and the rod body 302.

step2 Extend the piezoelectric body 301. This causes the tip of the rod 302 to move forward.

step3 Return the piezoelectric body 305 to the original position and bring the rod body 306 and the rod body 302 into contact with each other and hold them.

step4 The piezoelectric body 303 is contracted to separate the contact between the rod body 304 and the rod body 302.

step5 Put back the piezoelectric body 301. As a result, the rear portion of the rod 302 also moves forward.

step6 Return the piezoelectric body 303 to the original position and bring the rod body 304 and the rod body 302 into contact with each other and hold them. This returns to the initial state.

By repeating the above steps, the rod 302 can be moved forward, and naturally, the rod 302 can also be moved backward.
By using the inch worm mechanism 51 as a mechanism for moving the rod body 7, in order to increase the total movement amount like a differential screw mechanism, it is necessary to increase the length of the screw portion, which increases the size. The inch worm mechanism can be downsized for the total movement. It was confirmed that the performance was the same as that of the first embodiment.

[Advantages of the Invention] With the configuration described above, since the sliding portion is mainly provided in the atmosphere, the object provided in the vacuum environment can be positioned without using a special one for lubrication. It will be easy to do.

[Brief description of drawings]

FIG. 1 is a schematic view of an external positioning mechanism (atmosphere part) of the first embodiment, FIG. 2 is a schematic view of an internal positioning mechanism (vacuum part), FIG. 3 is a schematic view of a top part, and FIG. 4 is a mechanism of the present invention. ST used
M tunnel unit, FIG. 5 is a schematic view of the external positioning mechanism of the second embodiment (atmosphere part), and FIG. 6 is a schematic view showing a conventional example. FIG. 7 is a schematic view of a differential screw mechanism according to the present invention.
FIG. 8 is a first half operation diagram of the inchworm mechanism of the present invention. FIG. 9 is a second half operation diagram of the inchworm mechanism in the present invention. 1,1a …… External positioning mechanism 2 …… Internal positioning mechanism 6 …… Bellows 7 …… Bar body 10 …… Differential screw mechanism 15 …… Stepping motor 21 …… Frame 26 …… Piezoelectric element fine movement mechanism 27 …… Detection probe 29 …… Sample 42 …… Vibration isolation table 51 …… Inch worm mechanism

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Tokumoto 1-4-1, Umezono, Tsukuba-shi, Ibaraki Electronic Technology Research Institute, Industrial Technology Institute (72) Inventor Yoshiyuki Kobayashi 3-63 Takano, Misato-shi, Saitama Kosaka Research Institute Misato Plant (72) Shigeru Wakiyama 6-31-1, Kameido, Koto-ku, Tokyo Seiko Electronics Co., Ltd. (72) Kenji Omura 6-31-1, Kameido, Koto-ku, Tokyo No. Seiko Electronics Co., Ltd. (72) Creator Kazunori Ando 6-31-1, Kameido, Koto-ku, Tokyo Seiko Electronics Co., Ltd. Tsutomu Iitaka (56) Bibliography 59-152657 (JP) , U)

Claims (5)

[Scope of utility model registration request] 1. A bellows which is fixed to a main flange that separates a vacuum side and an atmosphere side and separates the vacuum side and the atmosphere side, and which is fixed to one end of the bellows and which penetrates the bellows and the main flange. A rod body provided, a jig for conveying an internal positioning mechanism installed at one end of the rod body on the vacuum side, and an external positioning mechanism mounted at the other end of the rod body on the atmosphere side, The external positioning mechanism includes a differential screw mechanism that moves the rod body back and forth, a linear bush that is provided on a saw body fixed to the main flange and serves as a guide for the rod body, and a drive that drives the differential screw mechanism. A fine positioning mechanism comprising: 2. A drive means for driving the differential screw mechanism, comprising: a first disc having a shaft of a large diameter screw of the differential screw mechanism fixed at its center and having through holes on both sides of the shaft. The first
And a rotation transmission rod for rotating the first disc that is slidably inserted into the through hole and that opposes the disc, and the rotation transmission rod is fixed. The fine positioning mechanism according to claim 1, comprising a second disc that is a stepping motor that rotates the second disc. 3. A bellows that is fixed to a main flange that separates the vacuum side and the atmosphere side and separates the vacuum side and the atmosphere side, and is fixed to one end of the bellows, and penetrates the bellows and the main flange. A rod body provided, a jig for conveying an internal positioning mechanism installed at one end of the rod body on the vacuum side, and an external positioning mechanism mounted at the other end of the rod body on the atmosphere side, The minute positioning mechanism, wherein the external positioning mechanism is an inch worm mechanism that moves the rod body back and forth. 4. The internal positioning mechanism is a plate that slides in a through hole of a main body, and a plate that generates a clamping force that is transmitted to a side surface of the frame after positioning the frame via a clamp block and a pressing plate. A spring, a laminated piezoelectric body that lifts the pressing plate to weaken the clamping force when the top is slid, a piezoelectric element body that is provided at the tip of the top and is minutely displaced by applying a voltage, 4. The micropositioning mechanism according to claim 1, comprising a detection probe attached to the tip of the element body and a sample stage installed at a position facing the detection probe. 5. A first coating containing titanium nitride, such as titanium nitride or titanium carbonitride as a main component, and the first coating on the sliding portion of the top incorporated in the internal positioning mechanism. For a vacuum comprising a second coating containing zirconium nitride or zirconium carbonitride as a main component, which is formed on the second coating, and a gold or gold alloy coating formed on the second coating. The fine positioning mechanism according to claim 4, wherein a lubricating film is formed.