JPH0259601A - Tip trimming device - Google Patents

Abstract

PURPOSE:To efficiently produce a tip having an optimum top end shape by polishing the tip while observing the top end shape of the tip. CONSTITUTION:After the inside of a vacuum vessel 27 is evacuated, an inert gas such as gaseous argon or gaseous helium is introduced into a vacuum vessel 27. A high voltage is impressed between the tip 21 and a fluorescent screen 23 by a DC high voltage power source 24. Then, the inert gas near the top end of the tip 21 is ionized and the ions plunge into a screen 23 so that the screen emits light. Impact is applied to the top end of the tip 21 by high-velocity atomic rays 26 released from a fast atomic ray source 25 while the electric field ion microscopic image at the front end of the tip 21 is held projected on a fluorescent screen 23. The front end of the tip is thus etched little by little.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention is directed to a scanning tunneling microscope (5CANNINGT).
UNN[! The present invention relates to a device for modifying the shape of the tip of a chip used in LING M [CRO3COPE: hereinafter referred to as STM].

(Conventional technology) STM is a device for observing the surface shape of solids.

Figure 2 is a schematic diagram of the 37M device. In Figure 0, l is a metal needle (tip) with an extremely sharp tip, 2 is the sample to be observed, 3 is a DC power supply, 4 is a resistor, and 5 is a tip. 6 is a power source for driving the drive mechanism 5. The drive mechanism 6 is a power source for driving the drive mechanism 5.

This operation is as follows. Bring tip 1 close to the surface of sample 2 and scan the tip along the sample surface (
While scanning in the X and Y directions in the figure, a voltage is applied to the sample 2 using the electric current B3, a tunnel current flowing between the tipped samples 2 is caused to flow through the resistor 4, and the potential difference generated across the resistor 4 is observed. Here, if the drive mechanism 5 is adjusted by the power source 6 so that the voltage across the resistor 4 is always constant, and the output voltage of the power source 6 at that time is recorded at each point on the surface of the sample 2, the surface of the sample 2 The unevenness will be displayed. A major feature of STMO is that it allows observation of fine patterns or atomic arrangements on the sample surface. STM
Of course, the tip shape of the tip 1 is very important, and it is said that the smaller the radius of curvature of the tip, the better the resolution of the STM image.

(Problem to be Solved by the Invention) The chip 1 is usually made by mechanically polishing or chemically polishing the tip of a metal wire such as platinum or tungsten having a thickness of 0.1 to 1a+a+.

It is sharpened to a radius of curvature of approximately 0.1n by electrolytic polishing or the like. Conventionally, the tip 1 is manufactured and trimmed by occasionally observing the shape of the tip using a scanning secondary electron microscope, field ion microscope, etc. while polishing the metal wire.
The method used is to continue polishing until the desired radius of curvature is reached.

In the conventional method, the polishing of the tip 1 and the observation of the tip shape were performed alternately and with separate devices, which not only resulted in poor chip manufacturing efficiency, but also made it difficult to stop polishing when the tip shape was optimal. was difficult.

The present invention was proposed to improve the above-mentioned drawbacks, and its purpose is to provide an apparatus for efficiently manufacturing an STM chip with an optimal tip shape.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a chip holder for mounting a chip, and a chip holder installed on an extension line of the axis of the mounted chip and facing the chip. a DC high-voltage power supply for applying a high voltage between the chip holder and the field ion microscope screen; and a DC high voltage power supply for applying a high voltage between the chip holder and the field ion microscope screen, and a The gist of the invention is a chip trimming device characterized by comprising a high-speed atomic beam source installed to irradiate a high-speed atomic beam onto the tip end of the chip.

(Function) In the present invention, since polishing is performed while observing the tip end shape of the chip, desired polishing can be performed on the chip.

(Example) Next, an example of the present invention will be described. Note that the embodiments are merely illustrative, and it goes without saying that various changes and improvements can be made without departing from the spirit of the present invention.

FIG. 1 shows an embodiment of the present invention, in which 21 is a chip, 22 is a chip holder, and 23 is a fluorescent screen, which are placed on an extension of the axis of the chip 21 and opposite to the chip 21. 24 is a DC high-voltage power supply for applying a high voltage between the chip holder 22 and the screen 23; 25 is a high-speed atomic beam source that emits high-speed atomic beams from a direction diagonal to the axis of the chip 21; The atomic beam 26 is irradiated. 27 is a vacuum container provided with a peephole 28, and the chip 21. Chip holder 2
2. A screen 23° contains a high-speed atomic beam source 25.

This operation is as follows. After the vacuum container 27 is sufficiently evacuated, an inert gas such as argon gas or helium gas is introduced at a pressure of 10-x to 10-' Torr. A high voltage is applied between the chip 21 and the fluorescent screen 23 by a DC high voltage power supply 24. The tip of the tip 21 is extremely sharp (because it is sharp, a very high electric field is applied to the tip, and the inert gas near the tip of the tip 21 is ionized (electric field ionization), which rushes into the fluorescent screen 23 and ionizes it. The tip of the tip 21 has an extremely small radius of curvature, whereas the fluorescent screen 23 is flat and has a very large radius of curvature, so the image of the tip of the tip 21 is magnified on the fluorescent screen 23. If you look at the tip of the tip 21 microscopically, the work function is different between the area directly above the lattice atoms and the area not directly above the lattice atoms, so there is a difference in the ionization of the inert gas. 21 The array of lattice atoms at the tip will be projected. (This kind of image of the tip tip is enlarged and projected onto a screen using electric field ionization of gas is called a field ion microscope.) , while the field ion microscope image of the tip of the tip 21 is projected onto the fluorescent screen 23, the tip of the tip 21 is bombarded with a fast atomic beam 26 emitted from the fast atomic beam source 25.
The tip is etched little by little, and the field ion microscope image on the fluorescent screen 23 changes accordingly.

This situation is observed through the observation window 28, and the etching by the high-speed atomic beam 26 is stopped at a predetermined point. In this way, trimming of the tip 21 is completed.

The greatest feature of the present invention is that the high-speed atomic beam 26 that bombards the chip 21 is an uncharged beam.
Etching progresses without being hindered by the strong electric field near the tip, allowing for "in-situ observation" of trimming, which dramatically improves processing efficiency.

Note that trimming with good axial symmetry can be achieved by adding a rotation mechanism to the chip holder 22 and performing etching with the high-speed atomic beam 26 while rotating the chip 21 around the central axis of the chip 21. Further, by providing a shutter between the chip 21 and the high-speed atomic beam f125 and controlling the opening and closing of the shutter, fine trimming adjustment is possible.

(Effects of the Invention) Although it is said that the quality of the tip end is extremely important in STM, there has been no efficient trimming device so far. One reason for this is that chip trimming and chip shape observation had to be performed alternately using separate devices.

According to the present invention, there is provided a chip holder for mounting a chip, and a chip holder on an extension line of the axis of the mounted chip,
and a field ion microscope screen installed opposite to the chip, a DC high voltage power supply for applying a high voltage between the chip holder and the field ion microscope screen, and a chip attached to the chip holder. By equipping the tip with a high-speed atomic beam source installed to irradiate the tip of the tip with a high-speed atomic beam from an oblique direction with respect to the axis of This has the effect of enabling the following.

[Brief explanation of the drawing]

FIG. 1 shows an embodiment of the present invention, and FIG. 2 shows an explanatory diagram of the operation of the 37M device. l...Chip 2...Sample 3...DC power supply 4 ・ 5 ・ 6 ・ 21 ・ 22 ・ 23 ・ 24 ・ 25 ・ 26 ・ 27 ・ 28 ・ Adjust the distance between the resistor chip and the sample Drive mechanism Drive power supply Chip Chip holder Fluorescent screen DC high voltage power supply High speed atomic beam source High speed atomic beam vacuum vessel Peephole

Claims (1)

[Claims] a chip holder for attaching the chip; a screen for a field ion microscope installed on an extension of the axis of the attached chip and facing the chip;
A DC high-voltage power supply for applying a high voltage between the chip holder and the field ion microscope screen, and a high-speed atomic beam irradiated to the tip of the chip from a diagonal direction with respect to the axis of the chip attached to the chip holder. A tip trimming device characterized by comprising: a high-speed atomic beam source installed so as to perform the following operations.