JPH09288115A - Method and apparatus for manufacture of sharp probe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a sharp probe in which the aspect ratio of the effective part of the probe is high and which uses various chemically stable materials. SOLUTION: In a method, a thin wire or a probe 1 which is used for a scanning probe microscope, a field emission electron source, a field emission ion source, an electrode or a sensor is made sharp. In this case, at least, a process in which a substance used to form the sharp probe is ionized and a process in which a voltage is applied to ions and in which the ions are concentrated on, and stuck to, the tip part of a probe base material by concentrating an electric field are used. Thereby, a protrusion 10 whose aspect ratio is high is formed at the tip part of the probe base material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a sharpened probe for sharpening a fine wire or a probe used in a scanning probe microscope, a field emission electron source, a field emission ion source, an electrode or a sensor, and the like. It relates to a device to be implemented.

[0002]

2. Description of the Related Art As a method of manufacturing a probe of a scanning tunneling microscope, when a metal wire of tungsten, platinum-iridium, etc. is cut by an electrolytic polishing method, a sharp tip generated at the cut portion of the metal wire on the electrolytic polishing liquid. In many cases, the converted part is used. A field emission electron gun chip is also manufactured by the same method as described above. As a typical example of the probe of an atomic force microscope, there are fine polyhedrons of silicon oxide and nitride and polyhedrons of diamond, which are produced by using a fine processing technology such as LSI (Chunli Bai, “Scanning Tunneling Micros
copy and its application ”, Springer Series in Sur
face Sciences 32, Springer, Schanghai, 1995). In addition to this, there has been proposed a method in which a sharpened probe is further sharpened by moving surface atoms in a high electric field while ion polishing or heating. The tip manufactured by such a method is composed of only a single atom or a few atoms at the forefront, and functions sufficiently as a tip of a scanning probe microscope or a tip of a field emission electron gun. However, except for a specially devised probe, the radius of curvature of the tip is about several hundreds of nm, and the number of atoms suddenly increases a little inside from the leading edge, and the tip diameter increases. Since the effective portion has a low aspect ratio as described above, there is a problem in that the probe cannot follow the surface shape having a large number of irregularities. Furthermore, since the surface atoms of the probe are oxidized or contaminants are adsorbed, in order to improve the reproducibility of the probe, check the atomic arrangement of the tip and clean the probe if necessary. It is said that sharpening must be done for each measurement. In particular, when performing scanning tunneling spectroscopy (STS), it is desirable to use a substance whose atom type of probe and its electronic state are known. Also,
Also in the field emission electron source, since the chemical stability of the tip of the chip is directly connected to the stability of the emission current, a chemically stable substance is desired. Further, in a probe of a magnetic force microscope, a thin film magnet is formed by depositing iron or nickel on the tip of a probe of tungsten or silicon. At present, the resolution determined by the size of the micro magnet and the size of the magnetization is several tens nm.
The degree is the highest. If a finer magnet can be formed at the tip of the probe, the resolution will be improved. Further, there is a method of forming a thin line of several nm on the substrate, but there is no method of forming this at the tip of the probe. Carbon nanotubes (Sumio Iijima, Nature, 354 (1991), p.56) are attracting attention as nanowires with high perfection.
A purification method for this has not been established, and a technique using a single nanotube as the tip of a probe has not been found in order to facilitate handling. Therefore, at present, in most materials, there is no known method for processing a high aspect ratio line of the effective portion of the probe. However, in the field of research such as micromachines, fine processing technology that can be applied to as many materials as possible is desired. In addition, if we can realize unprecedented ultrafine wire, we can
It is expected to be applied to various fields such as a probe for electrical engineering and analysis technology, and a new optical / electrical property is expected in a nanometer size structure.

[0003]

As described above, in the prior art, many of the structures of the probe and the ultrafine wire to be manufactured have a low aspect ratio (aspect ratio), and the materials are limited. However, there was a problem that there were large restrictions on usage.

An object of the present invention is to solve the above-mentioned problems of the prior art, and to manufacture a sharpened probe using various chemically stable materials having a high aspect ratio of the effective portion of the probe. To provide a method for manufacturing a sharp tip probe and an apparatus for carrying out the method.

[0005]

In order to achieve the above-mentioned object of the present invention, the present invention has a constitution as set forth in the claims. That is, the present invention is, as described in claim 1, a method for manufacturing a sharp probe for sharpening a fine wire or a probe used for a scanning probe microscope, a field emission electron source, a field emission ion source, an electrode or a sensor. hand,
Using at least a step of ionizing a substance forming a sharp tip and a step of applying a voltage to the ions to concentrate the ions on the tip of the probe base material by electric field concentration, This is a method for manufacturing a sharpened probe in which a high protrusion is formed on the tip of the probe base material. Further, as described in claim 2, the present invention is an apparatus for carrying out the method for manufacturing a sharpened probe according to claim 1, comprising a probe base material,
An actuator for adjusting the movement of the probe base material, a means for ionizing a substance forming a sharpened probe, a voltage is applied to the ions, and the ions are concentrated in an electric field to the tip of the probe base material. The manufacturing apparatus for a sharpened probe is provided with at least a control means for concentrating and adhering. Thus, by using the method and apparatus for manufacturing a sharpened tip according to claim 1 and claim 2, a part of atom or molecule or solid containing a substance used as a fine wire or a probe is ionized, and Ions can be collected at the tip of the probe by electric field concentration, so that a sharp probe with a high aspect ratio can be produced with good reproducibility. Further, the present invention is, as described in claim 3, a method for manufacturing a sharp probe for sharpening a fine wire or a probe used for a scanning probe microscope, a field emission electron source, a field emission ion source, an electrode or a sensor. The ion source to ionize atoms or molecules containing a substance that sharpens the tip of the probe base material; a step of controlling the velocity of ions from the ion source by the energy filter; A voltage is applied between the material and the energy filter, and at least the step of concentrating and attaching the ions to the tip portion of the probe base material by electric field concentration is used to form protrusions with a high aspect ratio on the probe base material. This is a method for manufacturing a sharpened probe formed at the tip. Further, as described in claim 4, the present invention is an apparatus for carrying out the method for manufacturing a sharpened probe according to claim 3, wherein the probe base material and the movement of the probe base material are adjusted. An actuator,
An ion source that ionizes a substance that sharpens the tip portion of the probe base material, an energy filter that adjusts the velocity of the ions, and a voltage is applied between the probe base material and the energy filter to generate the ions. Is a sharpened probe manufacturing apparatus including at least a control means for concentrating the electric field and concentrating and adhering it to the tip of the probe base material. As described above, by using the sharpened probe manufacturing method and the apparatus thereof according to the third and fourth aspects, when the ions generated by the ion source pass through the energy filter, the ions become almost zero in velocity. At this time, if a voltage is applied between the probe base material and the energy filter, the generated electric field attracts the ions to the tip of the probe, and the concentration of the electric field allows the ions to converge to a small area. There is an effect that ultrafine protrusions can be produced at the tip of the material with a high yield. The present invention also provides a scanning probe microscope, a field emission electron source, a field emission ion source,
A method of manufacturing a sharpened probe for sharpening a fine wire or a probe used for an electrode or a sensor, wherein at least a probe base material and an actuator for adjusting movement of the probe base material are provided inside a vacuum chamber, A step of disposing a predetermined substrate and forming a gas adsorption layer of a substance forming a sharpened probe on the substrate, applying a voltage between the probe base material and the substrate, At least using the steps of extracting field emission electrons and ionizing the gas component of the gas adsorption layer by the field emission electrons, and concentrating and attaching the ionized gas component to the tip of the probe base material by electric field concentration. A method for manufacturing a sharpened probe in which a protrusion having a high aspect ratio is formed at the tip of the probe base material. The present invention is also an apparatus for carrying out the method for manufacturing a sharpened probe according to claim 5 as described in claim 6, wherein at least the probe base material and the probe are provided inside the vacuum chamber. An actuator for adjusting the movement of the base material, a means for arranging a predetermined substrate and forming a gas adsorption layer of a substance forming a sharp probe on the substrate, and a voltage between the probe base material and the substrate. Is applied to extract field emission electrons from the probe base material, and a voltage is applied between the means for ionizing the gas component of the gas adsorption layer by the field emission electrons and the probe base material and the substrate, The sharpened probe manufacturing apparatus is provided with at least control means for concentrating the ions in the electric field and concentrating them on the tip of the probe base material. As described above, in the method and apparatus for manufacturing a sharpened probe according to claims 5 and 6, the adsorbed gas is ionized by the field emission electrons to become ions, which are attracted to the tip of the probe base material. A protrusion is formed. At this time, if the controller controls the distance between the tip of the protrusion and the substrate to a predetermined value in accordance with the growth of the protrusion, a stable field emission current and ion current can be obtained. It has the effect of forming with good reproducibility. The present inventors have formed a high aspect ratio microprobe on the tip of a probe base material that is easy to handle, and a method that can produce a high aspect ratio microprobe with various materials. As a result of examining the method of obtaining a chemically stable fine probe,
The present invention has been discovered. That is, the present invention relates to the production of a thin wire or probe used for a scanning probe microscope, a field emission electron source, a field emission ion source, or an electrode, a sensor, etc. A method and an apparatus for producing a sharp tip having a high aspect ratio by ionizing a part of the ions and collecting the ions at the tip of the probe by concentrating an electric field. Next, the principle of the present invention will be described based on FIGS. 1 (a) and 1 (b). 1A is a schematic diagram showing the configuration of an apparatus for producing a sharpened probe, and FIG. 1B shows the tip of the STM (scanning tunneling microscope) probe having a high aspect ratio. FIG. In the figure, 1 is an STM probe manufactured by a normal method, and 2 is an ion source. After passing through the energy filter 4, the ions 3 generated by the ion source 2 have a velocity of almost zero.
It has become. At this time, when a voltage is applied from the power source 5 between the STM probe 1 and the energy filter 4, ions are attracted to the probe 1 by the generated electric field. At this time, the trajectories of the ions 6 are not along the lines of electric force, but if the distance between the probe 1 and the energy filter 4 is shortened, the ions 6 can be converged into a small area by the concentration of the electric field. As a result, the fine protrusion 7 can be formed on the probe 1. The sum of the current of the emitted electrons from the tip of the protrusion 7 and the ion current from the energy filter 4 is
The distance L between the protrusion 1 and the energy filter 4 is moved by the actuator 9 according to a program that is monitored by the controller 8 and changes as the protrusion 7 grows. The protrusion 10 having an aspect ratio can be grown. The first feature of the present invention is that it becomes possible to form a very fine wire projection having a high aspect ratio on the tip portion of the probe base material, which has not been possible with the prior art. The second feature is that it is possible to form protrusions of ultrafine wires with a high aspect ratio by using various materials that cannot be manufactured by the conventional technology. The third feature is that a probe having an extra fine wire protrusion can be formed using a chemically stable material. As described above, according to the present invention, it is possible to provide a highly functional probe having projections of ultrafine lines having a high aspect ratio, which cannot be obtained by the conventional technique, by using various materials.

[0006]

Embodiments of the present invention will be described below. Although tungsten is used as the base material of the thin wire in the present embodiment, the same thin wire as tungsten can be produced by using carbon fiber, iron, nickel, cobalt, platinum-iridium, silicon, or the like. Have confirmed. Further, in the present embodiment, only field emission electrons are used for ionization of the adsorbed gas, but thermions or visible rays, ultraviolet rays, X-rays, electron rays, ion rays from a separately prepared radiation source are used. The ionization of the adsorbed gas is possible by any one or a combination of the above-mentioned excitations. These charged particles and light
It can be used not only for ionization, but also for heating the thin wire during or after manufacturing. By this heating, it is possible to promote the linear crystal growth of the ions flying to the thin wire. Further, although methane is used as a gas in the present embodiment, a fine wire made of a metal or a semiconductor can be produced by using a gas of a hydrocarbon, an organic metal, or a hydrogenated semiconductor such as silane other than this. can do. Furthermore, an ultrafine wire probe made of a composite material can be manufactured by alternately combining these plural gas species. FIG. 2 shows an example of the configuration of the manufacturing apparatus for the sharpened probe illustrated in the present embodiment. In the figure,
In the vacuum chamber 12, a gold substrate 14 fixed to a cooler 13 is provided in order to control gas adsorption on the probe. A tungsten probe base material 16 fixed to the actuator 15 is arranged opposite to this. Flow control devices 19, 21 from rare gas cylinder 17 and methane gas cylinder 18
Then, a mixed gas having a predetermined mixing ratio of rare gas: methane = 0 to 100: 1 is introduced into the chamber to form the adsorption gas layer 22 on the substrate surface. A voltage is applied from a power source 24 controlled by a controller (controller) 23 (10 to 10000 V),
When the field emission electrons 25 are extracted, the field emission electrons 25
As a result, the adsorbed gas is ionized to form ions 26, which are attracted to the tip of the probe base material 16 to cause carbide protrusions 27.
Is formed. At this time, the probe base material 16 is scanned, and at the same time, the controller 23 controls the distance (1 nm to 1 mm) between the tip of the protrusion 27 and the substrate 14 to a predetermined value in accordance with the growth of the protrusion 27. Since a stable field emission current and ion current can be obtained, an ultrafine wire with a uniform diameter can be formed. The diameter of the obtained ultrafine wire is 5
~ 1000 nm, aspect ratio 0.2: 1 to 10
0: 1.

[0007]

According to the method for manufacturing the sharpened tip of the present invention,
A probe having a high aspect ratio ultrafine wire having a diameter of 5 to 1000 nm, which cannot be obtained by the conventional technique, can be realized, and a probe having a chemically stable material, for example, an ultrafine wire of carbon or the like can be provided. It can be fabricated and used as an electrode or sensor for scanning probe microscopes, field emission electron guns, etc., as a probe for biological / medical, electronic / electrical engineering, analytical technology, and new optical and electrical properties of nanometer size. It can be expected to be applied to various fields where is expected.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an example of a typical configuration of a manufacturing apparatus for a sharpened probe according to the present invention.

FIG. 2 is a schematic diagram showing a configuration of a manufacturing apparatus of a sharpened tip probe exemplified in the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... STM (scanning tunneling microscope) probe 2 ... Ion source 3 ... Ion 4 ... Energy filter 5 ... Power supply 6 ... Ions that have passed through the energy filter 7 ... Extra fine protrusion 8 ... Controller 9 ... Actuator 10 ... High aspect Ratio protrusion 12 ... Vacuum chamber 13 ... Cooler 14 ... Gold substrate 15 ... Actuator 16 ... Tungsten probe base material 17 ... Rare gas cylinder 18 ... Methane gas cylinder 19 ... Flow rate regulator 20 ... Valve 21 ... Flow rate regulator 22 ... Adsorbed gas layer 23 ... Controller (controller) 24 ... Power supply 25 ... Field emission electron 26 ... Ion 27 ... Carbide protrusion L ... Distance

Claims (6)

[Claims] 1. A method of manufacturing a sharpened probe for sharpening a fine wire or a probe used for a scanning probe microscope, a field emission electron source, a field emission ion source, an electrode or a sensor,
Using at least a step of ionizing a substance forming a sharp tip and a step of applying a voltage to the ions to concentrate the ions on the tip of the probe base material by electric field concentration, A method for manufacturing a sharpened probe, characterized in that a high protrusion is formed on a tip portion of a probe base material. 2. An apparatus for carrying out the method for manufacturing a sharpened probe according to claim 1, wherein the probe base material, an actuator for adjusting the movement of the probe base material, and a sharpened probe are formed. A sharp tip probe comprising at least a means for ionizing a substance and a control means for applying a voltage to the ions to concentrate the ions in an electric field to concentrate the ions on the tip of the probe base material. Manufacturing equipment. 3. A method of manufacturing a sharpened probe for sharpening a fine wire or a probe used for a scanning probe microscope, a field emission electron source, a field emission ion source, an electrode or a sensor,
By the ion source, a step of ionizing atoms or molecules containing a substance that sharpens the tip of the probe base material, a step of controlling the velocity of ions from the ion source by the energy filter, and a probe base material A voltage having a high aspect ratio is applied to the tip of the probe base material by applying a voltage between the tip and the tip of the probe base material by applying a voltage between the energy filter and the electric field. A method for manufacturing a sharpened probe, which is characterized in that: 4. An apparatus for carrying out the method for manufacturing a sharpened probe according to claim 3, wherein the probe base material, an actuator for adjusting the movement of the probe base material, and a tip of the probe base material. An ion source that ionizes a substance that sharpens the part, an energy filter that adjusts the velocity of the ion, a voltage is applied between the probe base material and the energy filter, and the ions are concentrated by an electric field to search. An apparatus for manufacturing a sharpened probe, comprising at least control means for concentrating and adhering to a tip portion of a needle base material. 5. A method of manufacturing a sharpened probe for sharpening a fine wire or a probe used in a scanning probe microscope, a field emission electron source, a field emission ion source, an electrode or a sensor,
Inside the vacuum chamber, at least the probe base material, an actuator for adjusting the movement of the probe base material, and a predetermined substrate are arranged, and a gas adsorption layer of a substance forming a sharp probe is formed on the substrate. A step of forming, a step of applying a voltage between the probe base material and the substrate to extract field emission electrons from the probe base material, and ionizing the gas component of the gas adsorption layer by the field emission electrons, A sharpened probe characterized by forming a projection with a high aspect ratio on the tip of the probe base material by using at least the step of concentrating and attaching the ionized gas component to the tip of the probe base material by electric field concentration. Needle manufacturing method. 6. An apparatus for carrying out the method for manufacturing a sharpened probe according to claim 5, wherein at least a probe base material and an actuator for adjusting the movement of the probe base material are provided inside a vacuum chamber. , A means for forming a gas adsorption layer of a substance for forming a sharpened probe on the substrate, and applying a voltage between the probe base material and the substrate to form a probe base material A field emission electron is extracted from the probe, and a voltage is applied between the means for ionizing the gas component of the gas adsorption layer by the field emission electron and the probe base material and the substrate so that the ions are concentrated in the electric field. An apparatus for manufacturing a sharpened probe, comprising at least control means for concentrating and adhering to a tip portion of a base material.