JPH0795071B2 - Tip changer - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tip exchanging device used for a scanning tunneling microscope or the like.

2. Description of the Related Art A scanning tunneling microscope (STM) has been rapidly developed in recent years as an apparatus capable of observing the structure of a material surface with atomic resolution. First, the measurement principle of the scanning tunneling microscope will be described. An extremely sharp and pointed metal probe is brought to the surface of the sample to be measured up to a distance of about 10 Å, and a bias voltage of 10 mV to 2 V is applied between the sample and the probe, and a tunnel current of several nA flows. Since this current is extremely sensitive to the distance between the sample and the probe, feedback control can be used to keep this distance constant. On the other hand, the probe is attached to an actuator composed of a piezo element that makes fine movements in three axis directions.
The voltage applied for feedback control in the z direction when raster-scanning in the xy direction represents unevenness on the surface.

Such scanning tunneling microscope technology is creating peripheral technologies such as atomic force microscope (AFM) and near-field optical microscope (NFOM) observation devices, as well as ultrafine processing machines that enable atomic and molecular manipulation. is there. These techniques have a common feature of tracing a probe (tip) at a distance on the order of atoms, and in the observation device, these are collectively referred to as a near field microscope (NFM) or a scanning probe microscope (SPM).

The present invention relates to a device for exchanging a chip attached to an actuator in these devices.

In order to trace the tip at a distance on the order of atoms, it is necessary to first thoroughly eliminate mechanical vibrations that affect variations in this distance. First of all, it is required to consider the chip changer of the present invention from this viewpoint. Furthermore, it is necessary to make full use of the scanning tunneling microscope technology in ultra-high vacuum for research on the surface properties of materials, semiconductor process analysis, and material creation on the order of atoms. Also, a reliable mechanism system is required.

On the other hand, recently, as an example of a tip holder applied to STM for ultra-high vacuum, a mechanism for screwing a holder of a probe into an actuator for engaging a screw (Sugihara et al .: Proc. (1988)), a mechanism in which a plate-shaped holder with a welded probe is sandwiched between plate springs attached to an actuator (Tomitori et al .: Proceedings of the Japan Society of Applied Physics, 4a-N-3).
(1989)) has been announced.

However, with the above mechanism, there is a limit to the size and weight reduction of the chip holder while maintaining the rigidity of the chip holder, and there remains a problem as a chip holder that requires a high resonance frequency and high-speed response. At the same time, the movement of mounting the chip holder to the actuator is complicated, and there are problems such as restrictions on the structure of the mechanism for applying it to the STM for ultra-high vacuum, and uncertain mounting operation.

In view of these problems, the present invention solves this problem and applies it to an STM for ultra-high vacuum, which has high mechanical stability during high-speed scanning,
(EN) Provided is a chip exchanging device which has few mechanical structure restrictions and operates reliably.

Means for Solving the Problems In order to solve the above problems, the present invention provides a chip holder including a stepped pin having a chip fixed at one end, a means for moving the chip holder in the axial direction, an abutting member, and a thin leaf spring. It has a means to clamp the chip holder to the movable part of the actuator.When inserting, the tip of the thin leaf spring falls into the groove of the stepped pin to perform ratchet operation, and when pulling out, the ratchet is released by the projection and hooked in the groove of the pin. By pulling out the tip holder, the tip holder can be attached and detached only by uniaxial movement.

Further, the contact member has a V-groove structure, and the chip holder pin is pressed against the V-groove by a thin leaf spring.

The present invention can make the movable part of the actuator including the chip holder and the clamp part small in size and light in weight while maintaining high rigidity by forming the chip holder with the pin structure having the above-described configuration. 1) Resonance frequency is high and mechanical noise (Mechanic)
strong against al Noise).

(2) Excellent in high-speed response.

(3) The chip holder is less susceptible to inductive noise and is resistant to electrical noise.

In addition to the effect, the ratchet mechanism with the stepped pin and the thin leaf spring allows only one direction (axial direction of the pin).
Since the chip can be attached and detached by the movement of, it is particularly useful when applied to the STM for ultra-high vacuum in which the structure of the mechanism is restricted, and the tip can be attached and removed surely without requiring special skill.

Further, since the chip holder is pressed against the V groove by the thin leaf spring, the chip holder can be held stably and with high rigidity, and the position reproducibility of the chip holder due to chip replacement is good.

Embodiment A chip exchange apparatus according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 5 shows an STM unit to which the chip exchanging device of the present invention is applied. This STM unit is a STM mechanism devised for the purpose of surface research in ultra-high vacuum.
uth type) STM mechanism. (JEDemuth, et al:
J.Vac.Sci.Technol.A4 (3) 1320 (1986) (Demoose et al .: Journal of Vacuum Science and Technology A4 (3), 1320 (1986))) For x, y scanning in Fig. 5 (a) A piezo actuator 1 and a z-driving piezo actuator 2 are attached to blocks 3 and 4 in a tripot shape, and a probe 5 is attached on the actuator. On the other hand, the sample 6 is attached to the sample holder 7,
Furthermore, this holder is attached to the sample arm 8.
The sample arm 8 rotates about an axis 9 and the base plate 10
The sample can be moved closer to or away from the probe by the upper and lower sides of the carriage rod 12 sliding on the ball bush 11 attached to the. That is, when the carriage rod 12 moves upward, the sample arm 8 hits the catch 13 and the sample 6 moves away from the probe 5 as shown in FIG.
When the carriage rod 12 moves downward, the sample arm 8 hits the stopper 14, and the sample 6 moves downward in parallel while approaching the probe 5 and comes into contact with the foot 15. Sample 6
When the carriage rod 12 is further moved downward after the contact with the foot 15, the sample arm 8 is separated from the stopper 14 and the sample 6 is probed by the reduction lever fine movement mechanism with the contact point between the sample 6 and the foot 15 as a fulcrum. Approaching 5

The sample holder 7 is attached to the sample arm 8 by the dovetail type slider 16. This attachment / detachment is performed in vacuum by a feedthrough provided in the vacuum device.

Next, FIGS. 1 (a) and 1 (b) show a cross-sectional view and a side view of a chip mounting jig of a chip exchanging device of the present invention. For example, a thin needle with a sharpened tip of a single crystal of tungsten <111> or <110> direction is used as a tip (probe) 20,
This is attached to a stepped rod-shaped tip holder 21. Attach the tip holder to the tip holder 21,
At the time of removal, a groove 22 for hooking the chip holder 21 with a thin leaf spring of the jig and a groove 23 for attaching the chip holder to the actuator with the thin leaf spring are provided. The chip holder 21 is sandwiched by a chip holder holding cylindrical member 26 attached to a dovetail type slider 24 with a nut 25 and a thin leaf spring 28 attached to the cylindrical member with a screw 27.

2 (a), (b), (c) and (d) are the first
FIG. 9 is an explanatory diagram of an operation of attaching the chip holder 21 to the actuator by the jig for attaching chips explained in the figure. In the same figure (a), when the chip holder 21 set on the chip mounting jig approaches the chip mounting portion on the actuator, the same (b) is mounted at the moment, and the same (c) is mounted and cured. It shows how the ingredients go away. FIG. 7D is a plan view of the chip mounting portion on the actuator.

On the actuator, an abutting member 30 having a V groove 29 cut to hold the chip holder 21 and a block 33 having a thin leaf spring 31 attached by a screw 32 are adhered onto a base plate 34. When the tip holder 21 approaches the tip mounting part on the actuator as shown in FIG. 7A and the tip of the tip holder reaches the base plate 34 as shown in FIG. 7B, the thin spring 31 for mounting the tip holder causes the tip holder mounting thin spring 31 to move. Fall into the groove 23 of the holder, take the ratchet action and
The thin plate spring 31 presses the tip holder 21 against the side wall of the V groove 29 of the contact member 30 firmly while holding the tip holder firmly. After that, when the jig is moved in the direction opposite to the above insertion direction, the thin leaf spring 28 holding the chip holder of the jig is disengaged from the groove 22 of the chip holder as shown in FIG. Is mounted on the actuator.

The above operation is performed by using the chip mounting jig shown in FIG. 1 instead of the sample holder shown in FIG.
It can be done using the STM mechanism of the smooth type.

Next, FIGS. 3 (a) and 3 (b) show a sectional view and a side view of the jig for removing the chip holder of the chip exchanging device of the present invention. In the figure, members having the same shapes and functions as those shown in FIG. 1 are designated by the same reference numerals, and only the thin leaf spring 35 for removing the chip holder has a different structure from that shown in FIG.

4 (a), (b) and (c) are explanatory views of an operation of removing the chip holder from the actuator by the jig for removing the chip holder. When the tip holder removal jig approaches the tip holder mounting part on the actuator as shown in FIG. 9A and the tip of the tip holder 21 reaches the base plate 34 as shown in FIG. The tip 36 of the thin leaf spring 35 can push the thin leaf spring 31 for attaching the chip holder of the actuator away from the groove 23 of the tip holder, and at the same time, the thin leaf spring 35 for removing the tip holder 35
The tip holder withdrawing hook 37 of (3) falls into the groove 22 of the tip holder. As a result, when the chip holder removing jig is pulled away from the actuator as shown in FIG. 7C, the chip holder 21 is hooked by the hooking portion 37 and is recovered by the chip removing jig.

The above operation is carried out by attaching the chip removing jig shown in FIG. 3 to the sample arm 8 instead of the sample holder shown in FIG.
This can be done using the smooth type STM mechanism.

By making the tip exchange jig and the sample holder compatible with each other in this manner, the tip exchange can be performed without adding a new mechanism.

As in the above embodiments, the tip holder having the pin structure makes it possible to reduce the size and weight of the movable portion of the actuator including the tip holder and the clamp portion while maintaining high rigidity. In the example, the diameter of the tip holder pin is
A 1.5 mm, 7 mm long stainless steel rod was used.

As a result, (1) high resonance frequency and strong mechanical noise (Mechanical Noise), (2) excellent high-speed response, (3) chip holder is less susceptible to inductive noise, it is said to be strong against electrical noise (Electrical Noise) The effect was obtained.

As described in more detail above, the ratchet mechanism with stepped pins and thin leaf springs allows the chip to be attached and detached by movement in only one direction (the axial direction of the pin). It is useful when applied to STM. In addition, it is possible to securely attach and detach the chip without requiring special skills.

Further, since the chip holder is pressed against the V groove by the thin leaf spring, the chip holder can be held stably and with high rigidity, and the position reproducibility of the chip holder due to chip replacement is good.

This chip changer is a field ion microscope combined STM (FI
-STM) exerts a greater effect. In other words, in FI-STM, not only can the atomic structure at the tip of the needle-shaped tip used in STM be observed and characterized, but the tip of the tip can also be processed in atomic order by field evaporation. It is possible to use the desired chip in a high vacuum, and the effect is great.

In the above description, the scanning tunneling microscope (STM) is mainly used.
Although the tip exchanging device applied to the above has been described, it is needless to say that it is effective as a tip exchanging device for various observation devices and processing devices that are being derived from STM.

EFFECTS OF THE INVENTION According to the present invention, an STM that can reliably replace a chip with a relatively simple movement, is stable against mechanical noise and electrical noise, and is stable.
A technical tip changer can be provided.

[Brief description of drawings]

1 (a) and 1 (b) are a sectional view and a side view of a chip mounting jig which constitutes a chip exchanging device according to an embodiment of the present invention, and FIGS. 2 (a), 2 (b) and 2 (c). Is a cross-sectional view for explaining the operation of the chip mounting jig, FIG. 3D is a plan view of the chip mounting portion on the actuator, and FIGS. 3A and 3B are chip replacement in one embodiment of the present invention. A sectional view and a side view of a jig for removing a chip holder constituting the device, FIGS. 4A, 4B and 4C are sectional views for explaining the operation of the jig for removing the chip, and FIG. 5A. ) And (b) are STM to which the present invention is applied.
It is a side view which shows a mechanism. 20 …… Tips, 21 …… Tip holders (pins), 22, 23…
… Chip holder groove, 30… Contact member, 31… Thin leaf spring, 29… V groove of contact member.

Front Page Continuation (72) Inventor Isamu Sumida 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. Researcher Toshio Sakurai 1-3, Ikejiri, Setagaya-ku, Tokyo 2-103 Sanjuku Residence (56) References

Claims (2)

[Claims] 1. A means for axially moving a chip holder comprising a stepped pin having a chip fixed to one end, and means for holding the chip holder in a movable portion of an actuator by means of an abutting member and a thin leaf spring. During insertion, the tip of the thin leaf spring falls into the groove of the stepped pin to perform ratchet operation, and when withdrawn, the projection is used to release the ratchet and pull out the chip holder through the engagement with the groove of the stepped pin. Thus, the tip exchange device is configured such that the tip holder can be attached and detached only by uniaxial movement. 2. The chip exchanging device according to claim 1, wherein the abutting member has a V-groove structure, and the chip holder pin is pressed against the V-groove by a thin leaf spring.