JPS5840841B2 - microwave introduction flange - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Field of Application of the Invention The present invention relates to an improvement of a microwave introduction flange of a microwave ion source for an ion implanter.

(2) Prior Art FIG. 1 is a diagram showing the configuration of a microwave ion source that extracts a rectangular ion beam for use in an ion implanter.

In FIG. 1, microwaves generated by a microwave oscillator 1 are transmitted through a waveguide 2, a power meter 3, and a ridge waveguide 4.
The microwave is transmitted into the discharge chamber 7 formed between the ridge-shaped discharge electrodes 8 through the microwave three-dimensional circuit consisting of the above, and the microwave introduction flange 5 which serves as the vacuum pair of the ion source and the microwave transmission. be done.

A DC magnetic field by a magnetic field coil 6 is applied to the discharge chamber 7 in a direction perpendicular to the microwave electric field formed between the ridge-shaped discharge electrodes 8, and due to their interaction, the gas in the discharge chamber 7 is becomes plasma.

Further, only ions are extracted from the plasma generated in the discharge chamber 7 by an extraction electrode system 9 having a rectangular hole, thereby forming a strip-shaped ion beam 10.

The microwave introduction flange according to the prior art was a simple insulating disk as shown in FIG.

The role of the microwave introduction flange is to efficiently pass the microwave to the vacuum pair of the ion source. Regarding the latter, when considering the microwave introduction flange according to the conventional technology, the inside of the ridge waveguide 4 causes a Fuji-shaped discharge. The microwave propagation form inside the discharge chamber 7 having the electrode 8 is the same as that in a normal two-wire transmission line, but the microwave introduction flange 5 has a completely different form. , it was difficult to match the impedance between the front and back, making it impossible to efficiently transmit microwaves.

(3) Purpose of the Invention The present invention aims to reduce the impedance mismatch mentioned above.

(4) Detailed Description of the Invention In order to make it easier for microwaves to pass through the microwave introducing flange, a ridge portion of the ridge waveguide 4 and a ridge portion corresponding to the ridge portion are provided on the discharge chamber 7 side. The microwave introduction flange is made of a composite structure of an insulator member and a metal member, and is connected to the ridge-shaped discharge electrode 8 by a metal member.

(5) Examples Hereinafter, the present invention will be explained in detail with reference to Examples.

Fig. 3 shows the structure of the microwave introduction flange according to the present invention, and the outer diameter and thickness of the flange are the same as those according to the prior art. An arbitrarily shaped opening is provided in the portion of the disc 21 that bridges the ridge portion of the ridge waveguide 4 and the ridge-shaped electrode 8 provided on the discharge chamber 7 side, and the inner wall surface of this opening is metallized. , a metal piece 22 is hermetically joined and integrated within the opening.

According to this method, the microwave introduction flange part also
The microwave propagation mode is the same as that of a two-wire transmission line, and the microwave propagation from the ridge waveguide 4 to the discharge chamber 7 can be improved compared to the conventional technology.

FIG. 4 shows another embodiment.

The discharge electrode 8 in contact with the microwave introduction flange is constantly exposed to plasma and becomes a high temperature portion.

In this embodiment, cooling of the discharge electrode is also taken into consideration.

The insulator 21 is simply a disk with two round holes, and a metal component 22 with good thermal conductivity, which is fixed to the discharge electrode 8, passes through the insulator 21.

Furthermore, this metal component 22 has the same cross-sectional structure as the ridge waveguide 4, and is fixed to a metal flange 4' whose exterior is water-cooled.

The ion source portion (discharge chamber 7) is sealed in vacuum by an 01J ring 26 attached to the ridge portion of the discharge electrode 8.

With this configuration, compared to the first embodiment, the cooling effect of the discharge electrode can be increased without compromising impedance matching.

FIG. 5 shows yet another embodiment.

The insulator 21 has a structure in which a portion corresponding to the joint portion is removed from a disc, and a metal block 22 is fixed to that portion.

Further, the insulator 21 and the metal block 22 are integrated with an epoxy resin adhesive to prevent vacuum leakage between them.

A water cooling channel 24 passes through the metal block 22 to cool the discharge electrode 8.

In this embodiment, by determining the distance between the metal blocks 22 according to the dielectric constant of the insulator 21, almost perfect impedance matching between the ridge waveguide 4 and the microwave introducing flange 5 can be achieved.

(6) Summary As explained above, according to the present invention, compared to the conventional technology,
Microwave propagation from the ridge waveguide 4 to the discharge chamber 7 can be improved.

Furthermore, by cooling the metal portion 22, the effect of cooling the discharge electrode 8 can be increased.

[Brief explanation of drawings]

1 is a diagram showing the configuration of a microwave ion source for an ion implanter, FIG. 2 is a diagram showing a microwave introduction flange according to the prior art, FIG. 3 is a diagram showing a microwave introduction flange according to the present invention, and FIG. FIG. 5 is a diagram showing another embodiment of the present invention. In the figure, 4: ridge waveguide, 5: microwave introduction flange, 8: ridge-shaped discharge electrode, 21: insulator part, 2
2: Metal part, 24: Water cooling channel.

Claims (1)

[Claims] 1. Introducing microwaves through a ridge waveguide into a discharge chamber corresponding to the ridge portion of the ridge waveguide or having a Fuji-shaped discharge electrode to generate microwave discharge plasma within the discharge chamber; A microwave introduction flange provided at a microwave introduction portion from the ridge waveguide into the discharge chamber in the microwave plasma ion source adapted to extract ions from the plasma, the microwave introduction flange comprising an insulating material. It is characterized by having a composite structure in which a metal interconnection part is provided on a metal plate in a part bridging the ridge part of the ridge waveguide and the Fuji-shaped discharge electrode in the discharge chamber. Microwave introduction flange.