JP2569913Y2 - Ion implanter - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ion implantation apparatus for generating plasma.

[0002]

2. Description of the Related Art FIGS. 3 and 4 briefly show the structure of a plasma generation chamber (arc chamber) of a Barnas type ion source in a conventional ion implantation apparatus. The Barnas type ion source generates ions in the arc chamber 1, a slit is provided in one wall of the arc chamber 1, and positively charged ions are extracted from the slit by an extraction voltage of several tens keV.

Here, the ion generation will be briefly described. 3 and 4, first, the filament 2
A current of about 200 A is applied to emit thermoelectrons, and in the case of a gaseous source material or a solid source, a solid is heated and evaporated by a heater to a source gas inlet 3 or a metal vapor. The gas is introduced into the arc chamber 1 from the inlet 4. Thereby, the thermoelectrons accelerated by the voltage between the filament 2 and the arc chamber 1 collide with the introduced source gas and are ionized into free electrons and ions having a positive charge. At this time, the application of a magnetic field from the outside causes the thermoelectrons to make a spiral motion, thereby increasing the probability of collision between the thermoelectrons and gas molecules.

[0004]

One of the performance improvements required in the above-mentioned Barnas type ion source is to extend the life of the source. The source life is the time during which a beam can be emitted without releasing the source to the atmosphere.

There are mainly two factors that determine the source life. One is the replacement of the filament due to the consumption of the filament 2, and the other is that the source gas or the source gas is supplied to the filament insulator 5 and the reflector insulator 6. Metal vapor adheres and deteriorates their insulation.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and an object of the present invention is to provide a Balnas-type ion source ion implantation apparatus capable of realizing a longer life of the ion source.

[0007]

According to the present invention, two filaments are mounted facing each other in an arc chamber of a Barnas type ion source in an ion implantation apparatus, and a negative electrode is attached to an unused filament. And an ion implanter characterized in that the unused filament and the filament shield also serve as a filament reflector.

[0008]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention;

In the ion implantation apparatus according to the present invention, as shown in FIGS. 1 and 2, two filaments 2 are mounted in an arc chamber 1 of a Barnas type ion source so as to face each other. . Like the conventional filament, these filaments 2 are insulated from the arc chamber 1 together with the filament shield 7 via the filament insulator 5 so as to maintain insulation.
Each is configured.

In FIGS. 1 and 2, when the filament in use is consumed and needs to be replaced,
The + side of the filament power supply 9 is connected to another filament without breaking the vacuum.

Here, a negative electrode is connected to the unused filament, and the unused filament and the filament shield 7 have the role of the filament reflector 8 in the conventional structure.

[0012]

As described above, according to the present invention, the life of the filament of the arc chamber can be doubled, and the life of the ion source can be extended.

[Brief description of the drawings]

FIG. 1 is a schematic front cross-sectional view of an arc chamber according to an embodiment of the present invention.

FIG. 2 is a schematic side sectional view of the arc chamber according to the embodiment of the present invention.

FIG. 3 is a schematic front sectional view of a conventional arc chamber.

FIG. 4 is a schematic side sectional view of a conventional arc chamber.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Arc chamber 2 Filament 3 Source gas inlet 4 Metal vapor inlet 5 Filament insulator 6 Reflector insulator 7 Filament shield 8 Filament reflector 9 Filament power supply

Claims (1)

(57) [Scope of request for utility model registration] 1. An arc chamber of a Barnas-type ion source in an ion implantation apparatus, two filaments are mounted facing each other, and a negative electrode is connected to an unused filament. An ion implantation apparatus characterized in that a filament and a filament shield double as a filament reflector.