JPH11144948A - Magnet case for bucket-type ion source - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent permanent magnets which repel each other from springing out of a magnet case at housing of a plurality of permanent magnets when arranging the magnets in the direction in which their polarities become aligned with to each other. SOLUTION: A magnet case 20 has a square pipe-like shape and one 21 of the four side faces 21-24 forming a square pipe and one 25 of the two end faces 25 and 26 are formed in a continuous opened face. Then a folded piece 32 which is folded inward is provided along one side of the opened face 25, and an opening section 28 is formed at the bent piece 32 side end section of the side face 21 facing the piece 32 successively from the opened end face 25, so that an inserting port 30 for permanent magnets 6 is formed of the opening 28 and opened end face 25.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for attaching a permanent magnet for forming a cusp magnetic field to a bucket-type ion source using a cusp magnetic field for confining plasma. The present invention relates to a magnet case in which magnets are housed side by side in a direction in which the polarities are aligned with each other, and more specifically, to a means for preventing permanent magnets repelling each other from jumping out of the magnet case during storage.

[0002]

2. Description of the Related Art FIG. 3 is a sectional view showing an example of a bucket type ion source. This type of bucket ion source is disclosed in, for example, Japanese Patent Application Laid-Open No. 9-129150.

[0003] This bucket type ion source is provided with a plasma generating vessel 4 for generating a plasma 2, and forms a cusp magnetic field in the plasma generating vessel 4 on its outer wall, that is, on the outer peripheral portion of the side wall and on the upper lid. A plurality of permanent magnets 6 are attached. With this cusp magnetic field, the time for confining electrons and ions constituting the plasma 2 can be increased, and the generation efficiency of the plasma 2 can be increased.
An ion beam 10 can be extracted from the plasma 2 by the action of an electric field by an extraction electrode system 8 including, for example, a plurality of porous electrodes. The means for exciting the plasma 2 is not limited to a specific one, and includes, for example, arc discharge, high-frequency discharge, microwave discharge and the like.

Such a bucket type ion source is used, for example, in an ion doping apparatus (non-mass separation type ion implantation apparatus) and other ion implantation apparatuses.

In practice, a plurality of permanent magnets 6 are housed in a magnet case 12 as shown in FIG.

The magnet case 12 is made of a non-magnetic material, has a quadrangular cylindrical shape, and has one side surface 14 that is an open surface (that is, an open surface). In this case, three (3) prismatic permanent magnets 6 are arranged in a direction in which the polarities are aligned with each other (that is, a plurality of permanent magnets 6 are arranged so as to form one large permanent magnet. The same applies hereinafter). As shown, it is stored in the magnet case 12.

As shown in FIG. 5, for example, the permanent magnet 6 housed in the magnet case 12 has the opening surface 14 facing the plasma generation container 4 and is fixed to the outer wall of the plasma generation container 4 by, for example, a fixture 16. Attach.

[0008]

When a plurality of permanent magnets 6 are housed in the magnet case 12 side by side in the direction in which the polarities are aligned as described above, the respective permanent magnets 6 repel each other.

However, since the conventional magnet case 12 has only one side surface 14 opened, even if the permanent magnets 6 repelling from each other are put into the magnet case 12,
As it is, the permanent magnet 6 jumps out of the magnet case 12 by the repulsive force.

Conventionally, in order to prevent this, an operator
After the permanent magnet 6 is put in the magnet case 12, the bucket-type ion source (specifically, the plasma generation container 4 as shown in FIG. 5) while holding the permanent magnet 6 by hand so that the permanent magnet 6 does not jump out. However, since the permanent magnet 6 pops out as soon as it is out of care, the work is difficult and the workability of the mounting is poor.

In addition, the permanent magnet 6 is mistakenly
If it jumps out of the space, it may collide with another member such as the plasma generation container 4 and damage the permanent magnet 6.

Accordingly, the present invention provides a magnet case that can prevent mutually repelling permanent magnets from jumping out of the magnet case when a plurality of permanent magnets are housed side by side in a direction in which the polarities are aligned. Main purpose.

[0013]

The magnet case according to the present invention has a rectangular cylindrical shape, and has one of the four side surfaces and two end surfaces forming the rectangular tube as an opening surface, and one side of the opening surface. Along with the bent piece, an opening is formed at the end of the side facing the bent piece on the side of the bent piece, and an opening is formed at the end on the side of the bent piece. The above-mentioned end face forms an insertion opening for the permanent magnet.

[0014] According to the above configuration, the permanent magnets inserted into the magnet case from the insertion opening can be reciprocally acted upon each other.
Since it is caught by the bent piece at the lower part of the insertion slot, it does not jump out of the insertion slot. In addition, since the magnet case has a structure in which a total of five surfaces including four side surfaces including the side surface having an opening at the end and one end surface that is not an opening surface are closed,
The permanent magnet does not protrude from any place other than the insertion opening. Therefore, it is possible to prevent the mutually repelling permanent magnets from jumping out of the magnet case even if the permanent magnets are not manually pressed as in the conventional example.

[0015]

FIG. 1 is a perspective view showing an example of a magnet case according to the present invention together with a permanent magnet. The magnet case 20 accommodates a plurality (three in the illustrated example, but not limited thereto) of the above-described prism-shaped permanent magnets 6 arranged in a direction in which the polarities are aligned with each other. It has a square cylindrical shape corresponding to the permanent magnet 6, and is made of a non-magnetic material such as non-magnetic stainless steel (for example, SUS316).

Then, four side surfaces 21 forming the above-described square tube
24, and one end face 25 of the two end faces 25 to 26 is an open face (that is, an open face), and a bent piece 32 that is bent inward (turned back) is provided along one side of the open face 25. ing.

Further, an opening 28 is formed at the end of the side face 21 facing the bent piece 32 on the side of the bent piece 32, which is connected to the end face 25 which is an open face.
The opening 30 for the permanent magnet 6 is formed by the end surface 25 formed as the opening surface.

The length L ₁ of the opening 28 is equal to the length of the permanent magnet 6 positioned below (ie, inserted lastly) the opening 28.
Is preferably smaller than the length L ₂ of the permanent magnet 6 to be inserted last (that is, L ₁ <L ₂ ) in order to surely prevent the protrusion from jumping out of the opening 28. Since the insertion opening 30 becomes small and it becomes difficult to insert the permanent magnet 6, in order to maintain a balance between them (that is, to prevent the permanent magnet 6 from popping out and making it easy to put it in and out),
Is preferably to 0.3L ₂ ≦ L ₁ ≦ 0.7L about _2, also L ₁ ≒ 0.5 L ₂ about more preferably at them.

In this embodiment, the side surface 21 is formed like a lid by bending, and a gap 34 is formed between the side surface 21 and the side surface 24 intersecting the side surface 21 in order to facilitate the bending process. However, this is merely a matter of processing. For example, as shown in the embodiment shown in FIG. 2, the side surface 21 and the side surface 24 are brought into contact with each other without providing a gap, or are integrally continuous. You may let it.

In the magnet case 20, a plurality of permanent magnets 6 are slightly inclined from the insertion opening 30 so as to pass over the bent piece 32 at the lower part thereof, as shown by an arrow B in FIG. Insert with the front slightly down. In that case,
Although it is difficult to insert the permanent magnet 6 because the bent piece 32 hinders the open end face 25 alone, the opening 28 is provided at the upper part thereof, and the permanent magnet 6 escapes by the bent piece 32 here. Therefore, the permanent magnet 6 can be easily inserted into the magnet case 20 while avoiding the bent pieces 32. Further, since the opening 28 is provided, it is easy to take out the inserted permanent magnet 6 from the magnet case 20 by using the opening 28.

The permanent magnets 6 inserted into the magnet case 20 from the insertion port 30 in this manner are caught by the bent pieces 32 at the lower part of the insertion port 30 even when repulsive forces act on each other. Does not jump out. Further, since the magnet case 20 has a structure in which four sides 21 to 24 including the side 21 having the opening 28 formed at the end and one end 26 that is not an opening are closed in total, the insertion opening 30 is formed. The permanent magnet 6 does not fly out from other sources. Therefore, it is possible to prevent the mutually repelling permanent magnets 6 from jumping out of the magnet case 20 even if the permanent magnets 6 are not manually pressed as in the conventional example.

As a result, the work of attaching the permanent magnet 6 housed in the magnet case 20 to the bucket-type ion source, for example, to the bucket-type ion source as shown in FIG. 3, is facilitated, and the workability of the attachment is improved. . In this case, as in the case of the conventional example shown in FIG. 5, the attachment may be performed, for example, with the side surface 21 facing the ion source (specifically, the plasma generation container 4). Further, according to the magnet case 20, there is no danger that the permanent magnet 6 will accidentally jump out of the magnet case 20, so that the permanent magnet 6 can be prevented from being damaged.

The bent piece 32 may have elasticity in its bending direction, that is, in the direction of arrow C shown in FIG. 2, so that the bent piece 32 can be inserted when the permanent magnet 6 is inserted. Since the flexure 32 is provided, the insertion of the permanent magnet 6 becomes easier. Therefore, in this case, the opening 28
Of length L ₁ may be shorter.

[0024]

As described above, according to the present invention, the permanent magnets inserted into the magnet case from the insertion slot are caught by the bent piece at the lower portion of the insertion slot even if repulsive force acts on each other. Do not jump out of your mouth. Also, since the magnet case has a structure in which the four sides including the side face having the opening formed at the end and the one end face which is not the opening face are closed in total, the permanent magnet may protrude from other than the insertion port. There is no. Therefore, it is possible to prevent the mutually repelling permanent magnets from jumping out of the magnet case even if the permanent magnets are not manually pressed as in the conventional example. as a result,
The work of attaching the permanent magnet housed in the magnet case to the bucket type ion source is facilitated, and the workability of the attachment is improved. Further, since there is no possibility that the permanent magnet may accidentally jump out of the magnet case, it is possible to prevent the permanent magnet from being damaged.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of a magnet case according to the present invention together with a permanent magnet.

FIG. 2 is a perspective view showing another example of the magnet case according to the present invention.

FIG. 3 is a sectional view showing an example of a bucket type ion source.

FIG. 4 is a perspective view showing an example of a conventional magnet case together with a permanent magnet.

FIG. 5 is a cross-sectional view showing an example in which a permanent magnet housed in a magnet case is attached to an outer wall of a plasma generation container constituting a bucket type ion source.

[Explanation of symbols]

 Reference Signs List 6 permanent magnet 20 magnet case 21-24 side surface 25 end surface (opening surface) 26 end surface 28 opening 30 insertion opening 32 bent piece

Claims (1)

[Claims] The present invention is used for attaching a permanent magnet for forming a cusp magnetic field to a bucket-type ion source using a cusp magnetic field for confining plasma, wherein a plurality of prism-shaped permanent magnets have the same polarity. In a rectangular cylindrical magnet case made of non-magnetic material that is housed side by side in the direction, one of the four side surfaces and the two end surfaces forming the rectangular tube is an open surface, and along one side of the open surface, A bent piece is provided at the end of the side of the bent piece facing the bent piece, and an opening is formed at the end of the bent piece on the side of the bent piece, and the opening and the end face formed as the opening face are formed. A magnet case for a bucket type ion source, wherein an insertion opening for the permanent magnet is formed.