JPH05266860A - Mass separator and ion implantation device - Google Patents

Abstract

PURPOSE:To facilitate fabrication/assembly of a mass separator having a shim structure by providing arcuate magnetic pole plates on each magnetic pole end portion being parallel to the central axis of the inner wall of an analyzing tube near opposing faces of magnetic poles within the tube. CONSTITUTION:An analyzing tube disposed between N and S magnetic poles 3a, 3b disposed in a face-to-face relation with a gap G therebetween is equipped with built-in magnetic pole plates 2a, 2b, and this tube comprises a main body 1A forming a cavity portion permitting passage of ion beams therethrough, and a lid 1B for closing the opening formed on the main body 1A. The surfaces of the magnetic poles 3a, 3b contacting the analyzing tube are arcuately curved while the magnetic pole plates 2a, 2b are rectangular in cross section and the plates are conformed to the curved contours of the magnetic poles 3a, 3b. Each pole plate 2a, 2b is provided within the analyzing tube at the magnetic pole end portion being parallel to the central axis of the inner wall of the analyzing tube near each of the opposing faces of the magnetic poles 3a, 3b. Since the magnetic poles 3a, 3b are thereby separated from the protruded portions, fabrication of a shim structure is made easy. Besides, assembling/mounting are facilitated to enable miniaturization.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mass separator using an electromagnet, an ion implantation device including the mass separator,
And an analysis tube used for the mass separator.

[0002]

2. Description of the Related Art In conventional mass separators, the width of the magnetic poles (length in the direction perpendicular to the direction of the ion beam) is usually three times the magnetic pole spacing or more. This is because there is a region in which the magnetic field is nonuniform from the magnetic pole end to a distance approximately equal to the magnetic pole interval in the width direction of the magnetic pole, and this region is not used. For example, if the magnetic pole spacing is 50 mm,
When the magnetic pole width is 100 mm, there is no usable uniform portion. Therefore, in order to obtain a sufficiently wide uniform magnetic field region, it is necessary to make the magnetic pole width considerably large, and the mass separator becomes large. As a conventional technique for solving this problem, as described in Japanese Patent Application Laid-Open No. 63-292557, a shim structure is formed in which the end portions of the magnetic poles project in strips in the direction of the opposing magnetic poles to form ridges. As a result, there is an example in which the uniform magnetic field region is widened even if the magnetic pole width is small, and the size is reduced.

[0003]

The prior art described above has a shim structure in which the magnetic pole end has a ridge, and the ridge is formed integrally with the magnetic pole. The magnetic field distribution of the magnetic poles in the radial direction (width direction) is made uniform. However, the workability at the time of manufacturing the magnetic pole is not sufficiently taken into consideration, and since the ridge is integrally formed on the magnetic pole which is a mass of iron, the object to be handled is heavy and it is difficult to process. Furthermore, since the analysis tube and the magnetic pole are integrated, it was difficult to mount.

An object of the present invention is to facilitate the processing and assembly of a mass separator having a shim structure.

[0005]

In order to achieve the above-mentioned object, the present invention provides an analysis tube which also serves as a vacuum container inserted between a pair of magnetic poles having a central axis partially in the shape of an arc and a vacuum container inserted between the magnetic poles. In a mass separator in which an ion beam accelerated along the central axis travels in the analysis tube to perform mass separation, the analysis in the analysis tube and near each opposing surface of the magnetic poles. It is characterized in that an arc-shaped magnetic pole plate is provided on the inner wall of the tube at each magnetic pole end parallel to the central axis.

[0006]

As described above, in the magnetic pole plate provided at a position facing the end of the magnetic pole on the inner wall of the analysis tube, the ridge provided on the magnetic pole itself is separated from the ridge provided on the magnetic pole. As in the case, it has the effect of making the magnetic field distribution between the magnetic poles uniform. For this reason, it is possible to separately process only the ridges and then attach it in the analysis tube in the form of a magnetic pole plate, and to process the mass separator,
Easy to assemble. Therefore, when the shim structure is used, it is not necessary to increase the size of the magnetic poles, and the mass separator having the shim structure can be downsized.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS.
Will be described. FIG. 5 shows the entire mass separator of this embodiment, and FIGS. 1 and 2 show an analysis tube and N, S magnetic poles 3a, 3b in contact with the analysis tube of the mass separator shown in FIG. There is. 1 is a lateral sectional view of this embodiment, and FIG. 2 is a sectional view taken along the line AA 'of FIG.

The mass separator shown in FIG. 5 includes an analysis tube 1 and N, S arranged in contact with each other in the vertical direction of the analysis tube 1 so as to face each other.
The magnetic poles 3a and 3b, the C-type magnetic path 7 arranged so as to be coupled to the N and S magnetic poles 3a and 3b, and the N and S magnetic poles 3a and 3b.
And excitation coils 8a and 8b arranged around the.

In the mass separator shown in FIGS. 1 and 2, N and S magnetic poles 3a and 3b are arranged facing each other with a gap G therebetween.
And the analysis tube 1 arranged between the N and S magnetic poles 3a and 3b.
And non-magnetic support plates 6a, 6 installed in the analysis tube 1.
b, magnetic pole plates 2a and 2b partially welded and fixed to the support plates 6a and 6b and made of the same material as the magnetic poles 3a and 3b or a material having high magnetic permeability, and the support plates 6a and 6b.
And a plurality of support rods 5 for fixing to the analysis tube 1. The analysis tube 1 is a main body 1 which has the magnetic pole plates 2a and 2b inside and forms a cavity through which an ion beam 4 passes.
A and a lid 1B for closing the opening formed in the main body 1A. The analysis tube 1 and the magnetic poles 3a and 3b need not be fixed to each other. 1 and 2,
, The magnetic path 7 and the exciting coils 8a and 8b are omitted.

As shown in FIG. 1, the analysis tube 1 has magnetic poles 3a,
It is inserted between 3b. The analysis tube 1 is made of a non-magnetic material, and the cavity formed inside is kept in vacuum. Usually, the magnetic poles 3a and 3b are integrated with an electromagnet for generating a magnetic field, so that only the analysis tube 1 is inserted. The surfaces of the magnetic poles 3a and 3b in contact with the analysis tube 1 have an arcuate curved outer shape shown by a broken line in FIG. 2, and the magnetic pole plates 2a and 2b have a rectangular cross section and, as shown in FIG. It has a shape along the curved outer shape of 3b. Magnetic pole 3
The curved outlines indicated by the broken lines of a and 3b are shaped so as to substantially follow the center line of the ion beam 4 passing through the inside of the analysis tube 1. Therefore, the magnetic pole plates 2a and 2b are shaped along the center line. Has become. The magnetic pole plates 2a, 2b are attached to the inner wall of the portion of the analysis tube 1 which is in contact with the magnetic poles 3a, 3b at positions facing both ends of the magnetic poles 3a, 3b in the width B direction (r direction) through the inner wall. Be done. The mounting method is
The magnetic pole plates 2a and 2b are attached to the non-magnetic support plates 6a and 6b, respectively.
This is a method in which welding is performed at three points and the supporting rods 5 made of a non-magnetic material are fixed so as to be squeezed. Instead of tightening with the support rod 5,
The same effect can be obtained by directly welding to the wall of the analysis tube 1. At this time, by making the welding as small as possible, it is possible to prevent the disturbance of the magnetic field due to the welding. The ion beam 4 is the magnetic pole plate 2
Since it passes between a and 2b, it does not affect the magnetic pole plates 2a and 2b and the support rod 5 and has no influence. Further, the magnetic pole plates 2a and 2b do not have to be parallel to each other.

FIG. 3 shows the measurement results of the magnetic flux density with and without the magnetic pole plates 2a and 2b.
As shown in FIG. 3, the ridges are thus formed on the magnetic pole plates 2a, 2
Even if it is attached away from the magnetic pole as b, the magnetic pole plates 2a, 2
It is possible to obtain the effect of widening the uniform magnetic field region within a fluctuation of ± 1% as compared with the case without b.

According to this embodiment, the analysis tube 1 and the magnetic poles 3a,
Since 3b is a separate body, the mass spectrometer can be easily processed and assembled, and the magnetic pole can be made smaller.
Although the magnetic pole plates 2a and 2b each have a rectangular cross-sectional shape in the above embodiment, similar effects can be obtained even if the magnetic pole plates 2a and 2b have a semicircular shape or an L-shape.

An ion implanter using the above mass separator is shown in FIG. The illustrated ion implanter includes an ion source 11 for generating ions, and an electrode made of a plurality of metallic plates having a rectangular hole in the center, which is arranged in a passage of ions emitted from the ion source. The extraction electrodes 12 arranged side by side, the mass separator 13 shown in FIG. 1 arranged in the path of the ion beam passing through the extraction electrode 12, and arranged on the downstream side of the ion beam of the mass separator 13. A post-acceleration electrode 15 formed by arranging electrodes made of a plurality of metallic plates having rectangular holes in the center thereof,
A deflection magnet 16 made of an electromagnet is disposed downstream of the ion beam of the latter-stage acceleration electrode 15, and a rotating disk 17 is disposed downstream of the deflection magnet 16 and holds the wafer 18. It is configured.

In the ion implanter having the above-described structure, first, ions are generated by the ion source 11, and the ions pass through the extraction electrode 12 to generate the ion beam 14. Ion beam 14 generated by extraction electrode 12
Are sent to the mass separator 13 according to the present invention using an electromagnet, where only the necessary ions are separated. After that, the ion beam 14 is accelerated to a predetermined energy by the post-acceleration electrode 15. The ion beam 14 accelerated to a predetermined energy is deflected by a deflection magnet 16 made of an electromagnet to remove impurities. Then, the wafer 18 is arranged on a holder provided on the circumference of the rotating disk 17, and while scanning, the wafer 18 is scanned in a direction perpendicular to the ion beam 14 so that the deflected ions are transferred to the wafer 1.
Driven into 8.

According to this embodiment, since the mass separator can be miniaturized as described above, the driving device can be miniaturized.

[0016]

According to the present invention, since the magnetic pole and the ridge are separated, the shim structure can be easily processed. Further, the mass separator can be easily assembled and attached, and the size can be reduced.

[Brief description of drawings]

1 is a lateral cross-sectional view of one embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along the arrow AA ′ in FIG.

FIG. 3 is a diagram comparing magnetic flux density distributions with and without a magnetic pole plate.

FIG. 4 is a diagram in which the mass separator of FIG. 1 is applied to an ion implantation device, and is a diagram viewed from above the device.

5 is a cross-sectional view showing a state in which the mass separator of FIG. 1 is combined with an electromagnet.

[Explanation of symbols]

1 Analytical tube 2a, 2b Magnetic pole plate, 3a, 3b Magnetic pole 4 Ion beam, 5 Support rods 6a, 6b Support plate, 7 Magnetic path 8a, 8b Excitation coil 11 Ion source 12 Extraction electrode 13 Mass separator 14 Ion beam 15 Later acceleration Electrode 16 Deflection magnet.

Claims (5)

[Claims] 1. A pair of magnetic poles having an arc-shaped central axis, and an analysis tube inserted between the magnetic poles, which also functions as a vacuum container. An ion beam accelerated along the central axis is used for the analysis. In a mass separator that travels in a tube and performs mass separation, it corresponds to each magnetic pole end of the inner wall of the analytical tube in the analytical tube and near each opposing surface of the magnetic pole, the magnetic pole end being parallel to the central axis. A mass separator characterized in that an arc-shaped magnetic pole plate is provided at a position. 2. An analysis tube, which also has a central axis in the shape of an arc and which also serves as a vacuum vessel, and a pair of magnetic poles, which are opposed to each other with the analysis tube interposed therebetween, and are accelerated along the central axis. In a mass separator in which an ion beam travels in the analysis tube to perform mass separation, the ends of the inner wall of the analysis tube near the surfaces of the magnetic poles facing each other in the direction parallel to the ion beam travel direction of each magnetic pole. A mass separator characterized in that a magnetic pole plate having an end shape in a direction parallel to the ion beam traveling direction of each magnetic pole is provided at a position facing the portion. 3. An analytical tube, which also has a central axis in the shape of an arc and which also serves as a vacuum vessel, and a pair of magnetic poles, which are opposed to each other with the analytical tube interposed therebetween, and are accelerated along the central axis. In a mass separator in which an ion beam travels in the analysis tube to perform mass separation, a cross section in a direction perpendicular to a magnetic flux of a portion of the magnetic pole near the analysis tube is substantially parallel to the arc shape of the central axis. An arc-shaped magnetic pole plate is provided on the inner wall of the analysis tube that has an outer shape and is close to the mutually facing surfaces of the magnetic poles, at a position parallel to the central axis and facing each magnetic pole end. A mass separator characterized in that. 4. An analysis tube provided with a vacuum portion having a central axis of an arc shape for allowing an ion beam to pass therethrough, wherein the analysis tube is disposed between opposed magnetic poles and performs mass separation of the passing ion beam. An analysis tube characterized in that a magnetic pole plate having a shape of the end is provided at a position facing an end position in a direction parallel to the ion beam passage direction of the end faces of the magnetic pole facing each other. 5. An ion generator, an extraction electrode for extracting the ions, a mass separator for separating the mass of the ions, and an electrode for further accelerating the ions separated by the mass separator. The mass separator according to any one of claims 1 to 3, wherein the mass separator comprises a holder to which an object to be implanted into which the accelerated ions are mounted is attached. An ion implanter characterized by being present.