JPH0715840B2 - High speed atomic beam emitter - Google Patents

Description

TECHNICAL FIELD The present invention relates to a high-speed atomic beam radiation device used for sputtering or the like.

(Prior Art) An atom that is thermally moving in a room temperature atmosphere has a kinetic energy of about 0.05 ev, but molecules and atoms that fly with a much larger kinetic energy than this are collectively called “ It is called a "fast atom", and when it flows in a beam in one direction, it is called a "fast atom beam".

Conventionally, among the sputtering techniques, there is a sputtering technique that uses this high-speed atom beam in sputter etching, material composition analysis by secondary ion emission, and the like. Some devices that use this high-speed atomic beam utilize a gas such as chlorine or oxygen in addition to an inert gas such as argon used in ordinary sputtering. Further, these devices include one that ionizes the gas as described above and ejects it as it is, and one that ejects it as an electrically neutral high-speed atomic beam.

As the high-speed atom beam source for electrically neutralizing, an ion beam emitted from the ion source is made into an electrically neutral high-speed atom beam by a neutralizing means using an electron beam, or the like. There is a device for directly injecting a high-speed atomic beam as shown in FIG.

In the structure of the high-speed atomic beam emitting device of FIG. 7, first, a doughnut-shaped anode 2 is arranged along the side surface of the cathode 1 in the center of the cylindrical cathode 1. The cathode 1 and the anode 2 are connected to a DC high voltage power supply 3 arranged outside the vacuum container. By injecting, for example, oxygen gas from a gas injection nozzle 4 that is open inside the cylindrical cathode 1, and applying a high direct current voltage by a high direct current power source 3, a plasma 6 due to glow discharge is generated in the cylindrical cathode 1. Oxygen ions and electrons are generated. Further, the electrons emitted from the bottom surface of the cathode 1 vibrate at high frequency across the anode 2 and collide with oxygen gas to generate oxygen ions.

The oxygen ions thus generated are accelerated toward the bottom surface of the cathode 1 to become high-speed ions. Then, the oxygen ions come into contact with oxygen gas molecules remaining near the cathode 1 to return to oxygen atoms, and recombine with low-energy electrons that fold back high-frequency vibrations in the space near the bottom surface of the cathode 1. Then it returns to the oxygen atom.

Since such a high-speed oxygen ion loses little kinetic energy even when it returns to the oxygen atom as described above, the energy is directly transferred to the atom and becomes a high-speed atom.
Then, the fast atoms are emitted as a fast atom beam 8 from an emission hole 7 formed in one bottom surface of the cylindrical cathode 1.

(Problems to be Solved by the Invention) In the high-speed atomic beam radiation device as described above, in order to ionize the gas supplied into the radiation device, a high voltage is applied between the electrodes provided, and glow discharge or A spark discharge is generated and the supplied gas is ionized and accelerated. In this case, the high voltage is required to generate the discharge as described above, and the kinetic energy of the defected and accelerated ions ends up being high.

Here, in order to give a predetermined kinetic energy to this accelerated ion and neutralize it, deceleration or acceleration is required in many cases, and especially when it is desired to have a low kinetic energy,
There is a problem that efficiency is lowered due to increased scattering and more collisions with the electrodes.

Further, as mentioned above, conventional devices include a process of ionization and a process of re-neutralizing this ion. Each process has its own efficiency, and it is obvious that the more the processes, the lower the final efficiency.
For example, the efficiency of conventional ionization processes is from a few percent to about 40%, and the efficiency of neutralization processes is from about 10% to about 80%. Therefore, the final efficiency is about 30% at the highest.

An object of the present invention is to solve the above problems, to easily generate highly reactive fast atoms with high efficiency, and to set the kinetic energy of fast atoms arbitrarily from a low value to a high value. It is to provide a high-speed atomic beam emitter.

(Means for Solving the Problems) The above object of the present invention is to provide a vacuum container in which a plate electrode and a small electrode facing the plate electrode and having a surface area smaller than the plate electrode are arranged, and a plate electrode. It has a DC high-voltage power supply that is connected to a small electrode and is arranged outside the vacuum container, and injects gas molecules that have electric dipoles that are arranged to face the small electrode at one or more locations of the plate electrode. This is achieved by a high-speed atom beam emitting device having a nozzle for

That is, electric charges of the same size appear on both electrodes by the DC high-voltage power supply, but the surface area of the portion of the small electrode facing the plate electrode is set smaller than that of the plate electrode. The strength of the electric field becomes stronger than in the vicinity of the plate electrode, and the density of the lines of electric force becomes higher as it approaches the small electrode. This becomes more remarkable as the surface area of the portion of the small electrode facing the plate electrode becomes smaller (generally, the smaller the small electrode becomes). Here, when an electric dipole is injected into the electric field from the plate electrode side toward the small electrode at a certain speed from the nozzle, the electric charges on the small electrode side of the electric dipole are charged on the plate electrode side. The electric dipole will be accelerated toward the small electrode and will be emitted as a fast atom beam.

Such acceleration of the electric dipole toward the small electrode is affected by the electric field distribution (particularly in the vicinity of the small electrode) due to the surface area ratio of the facing portions of the small electrode and the plate electrode as described above. The larger the child's dipole moment, the greater this acceleration toward the small electrode. Moreover, since the direction of the electric dipole changes correspondingly to whichever of the polarities of both electrodes is the negative electrode or the positive electrode, there is no problem in this replacement.

As described above, the present invention utilizes the fact that the electric dipoles existing in the nonuniform strong electric field are accelerated in the strong electric field direction,
It is possible to radiate a fast atom beam without going through the processes of ionization / acceleration and neutralization of gas.

Further, by a configuration in which an ultraviolet light source that irradiates ultraviolet rays is arranged between the plate-shaped electrode and the small electrode in the vacuum container, the electric dipole being accelerated between both electrodes is excited by ultraviolet rays, and the reactivity is high. It is possible to emit a high-speed atomic beam.

(Embodiment) An embodiment of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a schematic configuration diagram showing an embodiment of the fast atom beam emitting device of the present invention.

A DC high-voltage power supply 28 arranged outside the vacuum container 29 is connected to the plate electrode 21 arranged in the vacuum container 29 and the thin wire electrode 22 which is a small electrode. A gas injection hole 23 is formed in the center of the plate electrode 21, and a gas nozzle 24 is guided to the gas injection hole 23 from the outside of the vacuum container 29. The thin linear electrode 22 is arranged so as to intersect with the blowing direction of the gas nozzle 24.

Elements other than the power supply 28 are housed in the vacuum container 29.
After the inside of 29 is sufficiently exhausted, gas molecules having an electric dipole are injected from the gas nozzle 24 at an arbitrary timing.

Here, as the electric dipole, those having a large dipole moment as described above are preferable. In addition, elements such as argon and helium, which are commonly used as high-speed atomic beams, have non-uniform electron distribution under high voltage, and thus behave as electric dipoles.

Depending on the connection direction of the power supply 28, the plate electrode 21 and the thin wire electrode 22
Can be set with either an anode or a cathode. For example, if the plate electrode 21 is an anode and the thin wire electrode 22 is a cathode as shown in FIG. 1, as shown in the cross-sectional view showing the state of electric force lines in FIG. The lines of electric force are concentrated from the plate-shaped electrode 21 toward the thin linear electrode 22, and the electric field becomes stronger as the electric line approaches the thin linear electrode 22.

The electric dipole injected from the gas nozzle 24 into the vacuum container 29 has the positive charge side facing the thin linear electrode 22 along the line of electric force, the electric field at the position of the positive charge end thereof is stronger than the electric field at the position of the negative charge end, Since the difference becomes larger as it gets closer to the thin linear electrode 22, the electric dipole is accelerated toward the combined vector direction of the velocity vector at the time of injection and the tangential direction vector of the electric force line. Then, by making the fine linear electrode 22 extremely thin compared to the injection range from the gas nozzle 24, collision with the fine linear electrode 22 of the electric dipole is reduced, and a high-speed atomic beam 27 is emitted from the emission port 30. Can be made. In addition, this radiation port 30
May have an opening at the central portion or may have an opening on the entire surface.

FIG. 3 is a schematic perspective view showing another embodiment of the present invention.
Here, elements similar to those in FIG. 1 are designated by the same reference numerals.

This high-speed atom beam emitting device is obtained by replacing the thin linear electrode 22 shown in FIG. 1 with a small ball electrode 32, and this small ball electrode 32 is located in the blowing direction of the gas nozzle 24.

It is obvious that the surface area is smaller than that of the thin linear electrode 22, and the convergence of the lines of electric force becomes a circle on a plane perpendicular to the blowing direction of the gas nozzle 24 and the amount of change in the convergence becomes large. Higher density.

FIG. 4 is also a schematic perspective view showing another embodiment of the present invention,
Similar to the embodiment of FIG. 3, the fine linear electrode 22 is replaced, and this is used as a ring-shaped electrode 34. put it here,
The same elements as those in FIG. 1 are designated by the same reference numerals.

Since the surface area is larger than when the small spherical electrode 32 is adopted, the amount of change in the convergence of the lines of electric force is small, but the fast atomic beam 27 can be sufficiently radiated and the radiation range and state are changed. Effective in a sense. If the diameter of the ring-shaped electrode 34 is too small, it will be equivalent to the case where the small ball electrode 32 is made large, so that the ring thickness is 10
About twice is preferable.

FIG. 5 is also a schematic perspective view showing another embodiment of the present invention.

In the vacuum container 29, the plate-shaped electrode 41 is composed of two rectangular plates having the same shape and the same area, and the gas nozzles 44 arranged in a line are arranged between the two plate-shaped electrodes 41. Then, in parallel with the gas nozzle 44, a thin linear electrode is provided.
42 are arranged. Further, one pole of the power source 28 is connected to both of the two plate electrodes 41, and the other pole is connected to the thin wire electrode 42.
It is connected to the.

In this high-speed atomic beam radiating device, the state of convergence of the lines of electric force on the plane perpendicular to the thin linear electrode 42 is the same as that in FIG. It becomes almost constant. Therefore, a wider range of high-speed atomic beam radiation can be performed.

Further, FIG. 6 is also a schematic perspective view showing another embodiment of the present invention. In this embodiment, in the apparatus shown in FIG.
An ultraviolet irradiation device 50 is arranged on the side wall of 29. The other constituent elements are the same as those in FIG. 1, and these elements are designated by the same reference numerals as in FIG. The ultraviolet irradiation device 50 irradiates ultraviolet rays to a portion where the electric dipole exists in the space between the plate electrode 21 and the thin wire electrode 22 in the vacuum container 29.

In this way, the electric dipoles that have received the ultraviolet rays are excited, and the fast atom beam 27 emitted can be made highly reactive. Such an ultraviolet irradiation device 50 can also be applied to the devices of the embodiments other than that shown in FIG.

In each of the above embodiments, the same result can be obtained regardless of which of the polarities of the plate electrode and the small electrode is the negative electrode or the anode.

(Effects of the Invention) As described above, according to the high-speed atomic beam radiation device of the present invention, the surface area of the portion of the small electrode facing the plate electrode is set smaller than that of the plate electrode, and the small electrode The density of the lines of electric force going toward is increased, and the gas containing electric dipoles is electrically directly accelerated by the non-uniformity of the electric field, so processes such as ionization and neutralization that cause a decrease in the efficiency of generation of fast atom beams. Is not present, and it is possible to obtain extremely high generation efficiency in which most of the injected electric dipoles are fast atom beams.

Further, even in the case of a low kinetic energy high-speed atomic beam of about several tens of eV, since it is an electrical direct acceleration, there are few factors causing a decrease in generation efficiency, and efficient generation is possible.

Further, by introducing an ultraviolet irradiation device, gas molecules can be excited and the reactivity can be enhanced.

As described above, it is possible to perform fine pattern processing and material analysis without damaging the material by a high-speed atomic beam with a low kinetic energy of about several tens of eV. Furthermore, since the high-speed atomic beam is electrically neutral as a whole, it is also very suitable for processing and analysis of insulators such as plastics and ceramics, which are difficult to apply with ion beams.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of a fast atom beam emitting device of the present invention, FIG. 2 is a sectional view showing a state of electric flux lines, FIG. 3, FIG. 4, FIG. 5 and FIG. Is a schematic configuration diagram showing another embodiment of the present invention, and FIG. 7 is a schematic perspective view showing a conventional high-speed atom beam emitting device. (Reference numeral in the figure) 1 ... Cylindrical cathode, 2 ... Donut-shaped anode 3 ... DC high-voltage power supply, 4 ... Gas injection nozzle 6 ... Plasma, 7 ... Emission hole 21 ... Plate electrode, 22 ... Fine wire electrode 23 ... Gas Injection port, 24 ... Gas nozzle 27 ... High-speed atom beam, 28 ... DC high-voltage power supply 29 ... Vacuum container, 30 ... Radiation port 32 ... Small ball electrode, 34 ... Ring electrode 41 ... Plate electrode, 42 ... Thin wire electrode 44 ... Gas nozzle 50 ... Ultraviolet irradiation device

Claims (2)

[Claims] 1. A vacuum container in which a plate electrode and a small electrode facing the plate electrode and having a surface area smaller than that of the plate electrode are arranged, and the plate electrode and the small electrode are connected to each other to provide the vacuum. A high-voltage direct-current power source disposed outside the container, and a nozzle for injecting a gas molecule having an electric dipole disposed at one or a plurality of positions of the plate electrode so as to face the small electrode, High-speed atomic beam emitter. 2. A high-speed atomic beam radiation according to claim 1, further comprising an ultraviolet light source for irradiating the electric dipole with ultraviolet rays between the plate-shaped electrode and the small electrode in the vacuum container. apparatus.