JPH06310066A - Ion source device - Google Patents

Abstract

PURPOSE:To sputter and ionize a target intensively, and obtain an ion beam over a large area by arranging a sputter target on the main plasma chamber side of a cover plate of a microwave plasma cathode. CONSTITUTION:Sub-plasma 23 is generated by microwave discharge in a sub- plasma chamber 9, and an electron is supplied to a main plasma chamber 2 through an electron emitting hole 12 and a through-hole 26. Noble gas such as argon or xenon in the chamber 2 is ionized, and main plasma 24 is formed. At this time, since a sputter target 25 is put in negative electric potential by a quantity of voltage of discharge electric power supply 19 to the plasma 24, it is sputtered intensively by a noble gas ion of the plasma 24, and a metallic particle is discharged in the chamber 2. The discharged metallic particle is ionized, and is shut up efficiently by a magnet 7, and is mixed with the noble gas ion by an extraction electrode 3, and a metallic ion beam is extracted over a large area. Thereby, an ion beam can be obtained over a large area with simple constitution.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ion source device using a microwave plasma cathode (hereinafter referred to as MP cathode) as an electron emission source.

[0002]

2. Description of the Related Art A conventional ion source device has a structure shown in FIG. In the figure, 1 is a main housing made of a non-magnetic metal such as stainless steel, 2 is a main plasma chamber formed by the main housing 1, 3 is an ion beam extraction electrode, and is a first electrode 4 and a second electrode 2. It is composed of an electrode 5 and a third electrode 6. 7
Is a permanent magnet or an electromagnet provided outside the main casing 1 for generating a magnetic field.

Reference numeral 8 is a sub-casing, 9 is a sub-plasma chamber formed inside the sub-casing 8, 10 and 11 are lid plates made of a ferromagnetic metal material on both sides of the sub-casing 8, and 12 is a lid plate 11. A plurality of electron emission holes formed in the above, 13 is an annular insulator between the sub-casing 8 and the main casing 1, and 14 is a gas inlet to the sub-plasma chamber 9.

15 is a coaxial cable for introducing microwaves,
Reference numeral 16 is an antenna at the tip of the coaxial cable 15, and 17 is an annular permanent magnet or electromagnet provided outside the sub-housing 8. The sub-housing 8 and the cover plate 11 form a magnetic circuit, and the sub-plasma chamber 9 is provided. To generate a magnetic field above the electron cyclotron resonance (ECR) condition. Reference numeral 18 denotes an MP including a sub-casing 8, a sub-plasma chamber 9, lid plates 10 and 11, an electron emission hole 12, an inlet 14, a coaxial cable 15, an antenna 16 and a magnet 17.
It is the cathode.

Reference numeral 19 denotes a discharge power source, the anode of which is the main housing 1.
In addition, the cathode is connected to the first electrode 4 via the cover plate 11 and the resistor 20 having a high resistance value, and the main casing 1 is set to the anode potential and the cover plate 11 is set to the cathode potential. Reference numeral 21 denotes an acceleration power supply, the anode of which is connected to the anode of the discharge power supply 19 and the cathode of which is grounded to apply an acceleration voltage to the first electrode 4. A deceleration power source 22 applies a negative voltage to the second electrode 5.

The sub-casing 8 is held at the cathode potential of the cathode of the discharge power source 19, and the tip of the antenna 16 is provided close to the wall surface of the sub-plasma chamber 9 so that microwave discharge can be easily caused. ing.

Next, when gas is supplied from the inlet 14 and microwaves are introduced into the sub-plasma chamber 9 via the coaxial cable 15 and the antenna 16, the sub-plasma chamber 9 is formed under the microwave cavity resonator condition. Even if not, microwave discharge is easily generated by the high electric field between the tip of the antenna 16 and the wall surface of the sub-plasma chamber 9, and the gas from the inlet 14 is ionized and the microwave plasma, that is, the sub-gas. Plasma 23 is generated.

Since the main plasma chamber 2 is biased to a higher potential than the sub-plasma chamber 9 by the discharge power source 19, the electrons ionized by the generation of the sub-plasma 23 pass through the electron emission holes 12 and the main plasma chamber 2 is discharged. And is discharged to the main plasma chamber 2, the direct current is sustained by the supplied electrons,
Ionized gas such as rare gas in the main plasma chamber 2 is ionized to generate the main plasma 24.

Next, by the beam extraction action of the extraction electrode 3, the ions are made into an ion beam from the generated main plasma 24 and guided to the sputtering chamber or the like. At this time, the main plasma 24 is efficiently confined in the main plasma chamber 2 by the cusp magnetic field of the magnet 7.

[0010]

Since the above-mentioned conventional device does not use a thermionic emission material such as a filament and uses the sub-plasma 23 generated by microwave discharge as an electron source, it does not react with an active gas such as oxygen. Even though it is an ion source that can be continuously operated for a long time, when used as a metal ion source,
In order to evaporate a substance and introduce it as a gas to extract an ion beam, for example, if the substance to be vaporized is a refractory metal such as tungsten, the vaporizing section must be heated to a temperature of several thousand degrees, and the device configuration is also high. There is a problem that it becomes very complicated. The present invention has been made in consideration of the above points, and an object thereof is to provide an ion source device capable of obtaining an ion beam having a large area with a simple configuration.

[0011]

In order to solve the above-mentioned problems, an ion source device of the present invention is a microwave plasma cathode as an electron emission source for generating electrons by plasma generation of microwave discharge, and a lid of the cathode. A main plasma chamber for confining the main plasma generated by DC discharge by supplying electrons from the electron emission holes formed in the plate, and an extraction electrode provided at a position facing the cathode of the main plasma chamber for extracting an ion beam from the main plasma are provided. In the provided ion source device, the sputter target is arranged on the main plasma chamber side of the lid plate. Further, the present invention is provided with a voltage applying means for making the sputter target a negative potential with respect to the cover plate.

[0012]

In the ion source device of the present invention configured as described above, since the sputter target is arranged on the main plasma chamber side of the lid plate of the microwave plasma cathode, the sputter target is concentrated by the rare gas ions in the main plasma chamber. Are sputtered and the sputtered particles are ionized in the main plasma chamber, and are extracted as an ion beam over a large area with a simple configuration. Further, the present invention is
Since the sputtering target is made to have a negative potential with respect to the cover plate by the voltage applying means, the sputtering efficiency is improved.

[0013]

EXAMPLES Examples will be described with reference to FIGS. 1 to 4. In these figures, the same reference numerals as those in FIG. 5 indicate the same or corresponding ones. (Embodiment 1) First, FIG. 1 showing Embodiment 1 is different from FIG. 5 in that a disk-shaped metal material such as tungsten or aluminum to be extracted as an ion beam is provided on the main plasma chamber 2 side of the lid plate 11. The sputter target 25 is disposed so as to have the same potential as the cover plate 11, and the sputter target 25 has an electron emission hole 12 communicating with the electron emission hole 12.
The same or more through holes 26 are formed.

Then, as in the conventional example, the sub-plasma 23 is generated by the microwave discharge in the sub-plasma chamber 9, and the electrons are supplied from the sub-plasma 23 into the main plasma chamber 2 through the electron emission holes 12 and the through holes 26. Then, the rare gas such as argon and xenon in the main plasma chamber 2 is ionized, and the main plasma 24 is formed.

At this time, the sputter target 25 has a negative potential with respect to the main plasma 24 by the voltage of the discharge power source 19, and therefore is sputtered intensively by the rare gas ions of the main plasma 24 and is a constituent material. The metal particles are released into the main plasma chamber 2. Then, the emitted metal particles are ionized by electrons or the like and efficiently confined by the magnet 7 forming the cusp magnetic field, and the extraction electrode 3
Mix with the rare gas ions, and the metal ion beam is extracted over a large area.

(Embodiment 2) Next, FIG. 2 showing Embodiment 2 is different from FIG. 1 in that a sputter target 2 is used.
5 is annular and lacks the central portion corresponding to the electron emission hole 12 of the cover plate 11. Then, similarly to the above, the sputter target 25 having the same potential as the cover plate 11 is intensively sputtered, and the metal ion beam can be extracted over a large area.

(Embodiment 3) Next, FIG. 3 showing Embodiment 3
2, the support flanges 27 are mounted between the flange portion of the main housing 1 and the flange portion of the cover plate 11 via the insulators 13, respectively, and the support flange 27 supports the annular sputter target 25 of FIG. The cathode of the bias power supply 28, which is a voltage applying means, is connected to the support flange 27, and the anode of the bias power supply 28 is connected to the cover plate 11. Therefore, the sputter target 25 has a negative potential with respect to the cover plate 11, is more efficiently sputtered, and the metal ion beam is extracted over a large area.

(Embodiment 4) Next, FIG. 4 showing Embodiment 4
3 is different from FIG. 3 in the following points. On the lid plate 11 side of the sputter target 25, a magnetic field generating means 29 including an annular permanent magnet for generating a magnetic field is provided on the surface of the sputter target 25, and a partition wall 30 is provided between the inner peripheral edge portion of the sputter target 25 and the lid plate 11. Is provided. Then, magnetic field lines 31 are generated on the surface of the sputter target 25 by the magnetic field generation means 29, the main plasma chamber 2 side of the sputter target 25 is in a magnetron discharge state, and the sputter target 25 is more efficiently sputtered, A metal ion beam is extracted over a large area.

[0019]

Since the present invention is constructed as described above, it has the following effects. In the ion source device of the present invention, since the sputter target 25 is arranged on the main plasma chamber 2 side of the lid plate 11 of the microwave plasma cathode 18, the sputter target 25 is not the main plasma chamber 2.
Since the rare gas ions are intensively sputtered and the sputtered particles are ionized in the main plasma chamber 2, the ion beam can be extracted over a large area with a simple configuration. Further, in the present invention, the sputtering target 25 is set to have a negative potential with respect to the cover plate 11 by the voltage applying means, so that the sputtering efficiency can be improved.

[Brief description of drawings]

FIG. 1 is a cut front view of a first embodiment of the present invention.

FIG. 2 is a cut front view of a second embodiment of the present invention.

FIG. 3 is a cut front view of a third embodiment of the present invention.

FIG. 4 is a cut front view of a fourth embodiment of the present invention.

FIG. 5 is a cut front view of a conventional example.

[Explanation of symbols]

 2 main plasma chamber 3 extraction electrode 11 lid plate 12 electron emission hole 18 microwave plasma cathode 24 main plasma 25 sputter target 28 bias power supply

Front Page Continuation (72) Inventor Katsuo Matsubara 47 Umezu Takaunecho, Ukyo-ku, Kyoto Nissin Electric Co., Ltd.

Claims (2)

[Claims] 1. A microwave plasma cathode as an electron emission source that generates electrons by plasma generation of microwave discharge, and the electrons are supplied from an electron emission hole formed in a cover plate of the cathode and generated by direct current discharge. An ion source device comprising: a main plasma chamber for confining a main plasma; and an extraction electrode provided at a position facing the cathode of the main plasma chamber to extract an ion beam from the main plasma, wherein the main plasma chamber of the lid plate is provided. Ion source device with sputter target on the side. 2. The ion source device according to claim 1, further comprising a voltage applying unit that sets the sputtering target to a negative potential with respect to the cover plate.