JPH0715839B2 - High speed atomic beam emitter - Google Patents

Abstract

A fast atom beam source comprises a evacuated cylinder, an anode set at one end or an intermediate portion of the cylinder, a cathode with fast atom emission orifices on it, and set at the other end of the cylinder, and a DC high voltage power supply for generating gas discharge by applying a high voltage between the anode and the cathode. A slit is provided on inside wall of the cylinder and a reservoir for oil or low-melting point metal is connected to the slit. A heater is set on the reservoir for vapourizing the oil or low-melting point metal. It supplies vapor of oil or low-melting point metal into the cylinder. Many ions of oil or low melting point metal are generated in glow through gas (the oil, vapor or the metal vapor) discharge by high voltage applying. They are accelerated towards the cathode. Then, they are neutralized after collision with the vapor of oil or low-melting point metal remaining near the cathode and are emitted from the orifices on the cathode. They constitute a fast atom beam. During such operation, the vapor of oil or low-melting point metal enters the cylinder through the slit and maintains an equilibrium condition of gas density in the cylinder. Thus, an automatic supply of the gas consumed as a fast atom beam is effected without any gas feeding device or any gas adjusting device.

Description

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

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

Among the conventional sputtering techniques, there is a sputtering method that utilizes this high-speed atom beam in sputter etching and material composition analysis by secondary ion emission. 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 a high-speed atomic beam source for electrically neutralizing, an ion beam emitted from an ion source is converted into an electrically neutral high-speed atomic beam by a neutralizing means using an electron beam, and There is a device for directly injecting a high-speed atomic beam as shown in FIG.

In the structure of the fast atom beam emitting apparatus shown in FIG. 4, first, a doughnut-shaped anode 2 along the side surface of the cathode 1 is arranged in the center of the cylindrical cathode 1. The cathode 1 and the anode 2 are connected to a DC 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 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 has little loss of kinetic energy even when it returns to an oxygen atom as described above, it is inherited by the atom as it is 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.

Since such a high-speed atomic beam is non-charged, it can be used not only for metals and semiconductors, but also for insulators such as plastics and ceramics, which ion beams are not good at processing.

(Problems to be Solved by the Invention) In the high-speed atomic beam emitting device as described above, gas must be constantly supplied into the emitting device in order to supplement the substance emitted as a high-speed atomic beam.

Therefore, since it is necessary to install a device for supplying gas from the outside of the vacuum container, the entire device becomes large.

In addition, since the gas is introduced into a part of the vacuum container by introducing the gas for utilizing the gas discharge, the preferable high vacuum state until then must be slightly lowered, and in addition, the state inside the vacuum container is kept constant. Therefore, a device for adjusting the gas supply amount is also required.

Further, in the case of a substance that easily adheres to the wall surface and becomes a liquid, there is a problem that the inside of the device is contaminated due to dew condensation particularly due to a decrease in internal temperature after the device is stopped.

An object of the present invention is to solve the above-mentioned problems, and to provide a high-speed atomic beam radiation device that is compact in size and does not deteriorate the degree of vacuum and can use a substance that easily becomes liquid. Especially.

(Means for Solving the Problems) The above object of the present invention is to provide a cylindrical cylinder having a slit opened in the side wall surface and the inside of which is kept in a vacuum state, and connecting the slit to an oil or a low melting point metal. A reservoir which is stored, a heater which is disposed in the reservoir and heats and vaporizes the oil or the low melting point metal into the cylinder from the slit, and a heater which is disposed on the outer wall of the cylinder above the slit and collides with the inner wall surface at that position. A cooling member for cooling the gas molecules to be attached to the wall surface as a liquid,
A structure comprising a plate-shaped anode arranged at an opening at one end of the cylindrical cylinder and a DC high-voltage power source for generating a discharge by applying a voltage between a cathode arranged at the other end and having a discharge hole. Achieved by a fast atom beam emitter.

That is, as described above, the reservoir is connected to the slit in the same vacuum state as the cylindrical cylinder, and if necessary, this reservoir is heated by a heater, so that the oil or low melting point metal stored in the reservoir is Evaporate to fill the cylindrical cylinder and equilibrate at a certain density. If voltage is applied from the DC high voltage power supply in this state,
A gas discharge is generated in the cylindrical cylinder, the ionized atoms in the plasma are accelerated toward the cathode, contact the gas molecules remaining near the cathode, are neutralized, and are emitted as a fast atom beam. It Then, although the gas molecule density is reduced by the radiation of the fast atom beam, the gas molecule density is always maintained by the evaporation from the reservoir.

Therefore, it is not necessary to connect a device for introducing gas from the outside or a device for adjusting the introduced amount, and the entire device can be downsized. Further, the volume required for vacuum does not change because there is no gas introduction device and the like, and the decrease in vacuum degree can be minimized.

Further, due to the cooling member provided above the slit, the gasified oil or low melting point metal is condensed on the inner wall of the cylindrical cylinder at that portion, flows through the inner wall of the cylindrical cylinder, flows down into the slit, and is stored in the reservoir. React with oil or low melting point metal.

Therefore, for example, after the use of the entire apparatus is stopped, the gas remaining in the cylindrical cylinder is condensed on the inner wall and remains, and the cathode part which is the emitting part of the fast atom beam and the target outside the part are contaminated. Can be prevented. In particular, by providing the slits on the entire circumference of the inner wall of the cylindrical cylinder, it is possible to completely prevent the slits from flowing down below the slits.

It is also possible to use a plate-shaped cathode instead of the plate-shaped anode, use the cylindrical cylinder as an anode, and connect a high-voltage DC power supply to the plate-shaped cathode and the cathode having the emission hole and the cylindrical cylinder anode. Is.

(Embodiment) An embodiment of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a schematic perspective view showing an embodiment of the fast atom beam emitting device of the present invention, and FIG. 2 is a sectional view thereof.

A slit 25 is opened over the entire circumference in the central portion in the longitudinal direction of the cylindrical cylinder 21 to be evacuated, and a donut-shaped reservoir 22 that surrounds the entire lower circumference of the vertically standing cylindrical cylinder 21 is formed. It is connected to the slit 25 with an inclined wall surface. Oil or a low melting point metal 23 is stored in the reservoir 22, a heater 24 is installed on the bottom surface of the reservoir 22, and a cooling pipe 27 surrounds the wall surface of the cylindrical cylinder 21 above the slit 25.

A cathode 29 having a fast atom beam emission hole is arranged at the lower end of the cylindrical cylinder 21, and an anode is provided at the upper end of the cylindrical cylinder 21.
28 are arranged. A direct current high voltage source 32 is connected to the anode 28 and the cathode 29. The parts other than the DC high voltage source 32 are installed in a vacuum. Therefore, the anode 28 and the cylindrical cylinder 21 do not have to be in close contact with each other.

Further, as the material of the cylindrical cylinder 21, many materials such as metal and ceramics can be used.

Next, the operation of this embodiment will be described.

The oil or the low-melting point metal 23 in the reservoir 22 is in a low temperature state before the operation of the apparatus, and is hardly evaporated in the cylindrical cylinder 21. Now activate the heater 24 and activate the reservoir 22
When the inside reaches a predetermined temperature, oil or low melting point metal 23 becomes the second
Evaporate in the cylindrical cylinder 21 as indicated by the dotted arrow in the figure, and reach an equilibrium state with a desired gas density.

At this time, if voltage is applied from the DC high voltage source 32,
The gas discharge spreads from 28, and the oil or the low melting point metal becomes ions and moves toward the cathode 29 at high speed. Then, it collides with the neutral oil or the molecules of the low melting point metal remaining in the vicinity of the cathode 29, is neutralized, and is emitted from the high-speed atom beam emitting hole of the cathode 29.

The oil or low melting point metal evaporated in the cylindrical cylinder 21 in this way is consumed as a high-speed atomic beam and the internal gas density tends to decrease, but evaporation from the reservoir 22 is always performed. Therefore, the consumed molecules are automatically replenished, and a constant amount of fast atom beam is always emitted.

Further, the cooling pipe 27 always cools the outer wall of the cylindrical cylinder 21 during high-speed atomic beam radiation, and therefore oil or vaporized gas of the low melting point metal is condensed on this inner wall to form droplets in the slit 25. It flows down and joins the oil or the low melting point metal 23 in the reservoir 22. In other words, this results in promoting evaporation in the reservoir 22 that is more than the amount consumed as a high-speed atomic beam, further stabilizing the gas density in the cylindrical cylinder 21, and convection of the oil or the low melting point metal 23 in the reservoir 22. Can be promoted. In addition, when the apparatus is stopped, the gas inside the cylindrical cylinder 21 is quickly condensed to minimize the adhesion to other parts when the temperature is lowered, thereby suppressing the progress of dirt.

FIG. 3 is a schematic sectional view showing another embodiment of the present invention.
Here, elements similar to those in FIGS. 1 and 2 are designated by the same reference numerals.

In this high-speed atomic beam radiation device, the cylindrical cylinder 21 and the reservoir 22 are made of a metal anode (only the cylindrical cylinder 21 may be made of metal), and a cathode 41 is provided at the upper end of the cylindrical cylinder 21 with a space therebetween. Alternatively, they are arranged with the insulator 26 sandwiched therebetween. Further, the cathode 29 is arranged in the same manner as in FIGS. 1 and 2, and a DC high-voltage power supply 42 connects the cylindrical cylinder 21 and the cathodes 29, 41.

As a difference from the device of the above-mentioned embodiment, the part where the gas discharge is generated from the cylindrical cylinder 21 is different, but the operation is almost the same, and the neutralized fast atom beam is radiated from the radiation hole of the cathode 29. It

(Effects of the Invention) As described above, according to the high-speed atomic beam radiation device of the present invention, the reservoir provided with the heater is connected to the slit in the same vacuum state as the cylindrical cylinder,
Since the oil or the low melting point metal stored in the reservoir evaporates so that the gas density in the cylindrical cylinder becomes equilibrium, the gas radiated as a fast atom beam can be automatically supplemented. Since it is not necessary to provide a gas replenishing device and a replenishing amount adjusting device, the entire device can be downsized. Further, since the gas introduction device is not installed in this way, the vacuum volume does not change and the change in the degree of vacuum can be minimized. That is, it can be used in a high vacuum state.

Further, the cooling member provided above the slit activates the evaporation of the oil or the low melting point metal, further stabilizing the equilibrium state of the gas density in the cylindrical cylinder and promoting the convection of the oil or the low melting point metal in the reservoir. Can be achieved. In addition, it is possible to suppress the contamination of the entire device after the use is stopped.

[Brief description of drawings]

FIG. 1 is a schematic perspective view showing an embodiment of a fast atom beam emitting device of the present invention, FIG. 2 is a sectional view of the device of FIG. 1, and FIG. 3 is a sectional view showing another embodiment of the present invention. FIG. 4 is a schematic perspective view showing a conventional high speed atom beam emitting device. (Numerals 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 ... Cylindrical cylinder, 22 ... Reservoir 23 ... Oil or low melting point Metal 24 ... Heater, 25 ... Slit 24 ... Heater, 27 ... Cooling tube 28 ... Anode, 29 ... Cathode 31,42 ... DC high voltage power supply 41 ... Cathode

Claims (2)

[Claims] 1. A cylindrical cylinder having a slit opened in the side wall surface and the inside of which is kept in a vacuum state, and a reservoir connected to the slit for storing oil or a low melting point metal.
A heater disposed in the reservoir to heat and evaporate the oil or the low melting point metal from the slit into the cylinder, and a gas molecule disposed on the outer wall of the cylinder above the slit and colliding with the inner wall surface at that position for cooling. By applying a voltage between the cooling member to be attached as a liquid to the wall surface thereof, the plate-like anode arranged at the opening at one end of the cylindrical cylinder and the cathode arranged at the other end with the emission hole. A high-speed atomic beam radiation device having a high-voltage direct-current power supply for generating a discharge. 2. A high-speed atomic beam radiation device according to claim 1, wherein the plate-shaped anode is replaced by a plate-shaped cathode, the cylindrical cylinder is used as an anode, and the plate-shaped cathode and the cathode having the emission holes are provided. A device characterized in that a direct current high voltage power supply is connected to the cylindrical cylinder anode.