JP2606294B2 - Ion implanter - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a so-called dual-type ion implantation apparatus in which an ion beam is selectively introduced into two implantation chambers.

[Conventional technology]

FIG. 4 partially shows a conventional example of this type of ion implantation apparatus.

That is, in this ion implantation apparatus, a vacuum vessel 4 for introducing an ion beam 2 from an ion source (not shown) is branched into an inverted Y-shape, and an injection chamber 12 is provided at each end via vacuum valves 8a and 8b.
a and 12b, respectively, these two injection chambers 12a, 12b
The ion beam 2 is switched and introduced using the deflecting means 3 and the like.

The vacuum valves 8a and 8b close the openings 7a and 7b for the passage of the ion beam 2 of the partition plate 6 provided at the branch portion of the vacuum vessel 4, respectively. Ring-shaped packing 9a, 9b as hermetic seal part by mechanical contact
Respectively.

Note that, in each of the implantation chambers 12a and 12b, holders 13a and 13b that are rotated to a horizontal state for attaching and detaching the substrate 14 and a vertical state for implanting ions into the mounted substrate 14 are provided, respectively. .

In addition, vacuum back chambers 16a, 16b are provided at the rear of the two injection chambers 12a, 12b for taking the substrate 14 in and out between the chamber and the atmosphere.
Are adjacent to each other. 18a-21a and 18b in the figure
Reference numerals 21b to 21b denote vacuum valves for this purpose, and arrows indicate an example of a path for carrying in and out the substrate 14.

[Problems to be solved by the invention]

The vacuum valves 8a and 8b are used for both injection chambers during maintenance work.
For the purpose of completely separating the vacuum of the four vacuum containers between or between 12a and 12b or upstream thereof, packings 9a and 9b for complete airtight sealing are provided.
a and 10b are heavy because they have enough thickness to withstand vacuum pressure.

Accordingly, opening and closing these vacuum valves 8a and 8b each time the ion beam 2 is switched between the implantation chamber 12a and the implantation chamber 12b is not only because of the life of the packings 9a and 9b and the support of the valve bodies 10a and 10b, but also because There was a problem in generating dust from them.

Therefore, conventionally, it was usual that the vacuum valves 8a and 8b were kept at the open position during the normal ion implantation.

However, in this case, for example, as shown in the drawing, during the ion implantation on the implantation chamber 12b side, the substrate 14 is implanted on the implantation chamber 12a side.
When the vacuum valves 20a and 20a are opened to take in and out of the chamber, the vacuum chamber 20a is affected by the degree of vacuum of the vacuum preparatory chamber 16a (generally lower than the vacuum degree of the injection chamber 12a, for example, about 100 mmTorr).
Has a problem that the degree of vacuum of the implantation chamber 12b during the ion implantation operation is reduced through the openings 7a and 7b of the partition plate 6.

As a result, for example, if the reduction in the degree of vacuum falls below an allowable limit in the ion implantation process, for example, 1 × 10 ⁻⁶ Torr, the ion implantation process must be interrupted. In this case, there has been a problem that it is difficult to uniformly irradiate the substrate 14 due to the influence of the degree of vacuum reduction.

One solution to prevent this is to use the vacuum valves 20a, 2
Before opening 1b or the vacuum valves 20a and 21b to communicate the vacuum spare chamber 16a or 16b with the injection chamber 12a or 12b,
The degree of vacuum in the vacuum preparatory chambers 16a and 16b is sufficiently set (for example, 10 ⁻⁶
It should be increased to a value close to the degree of vacuum of the injection chambers 12a and 12b such as about Torr), but for that purpose, it is necessary to use a large-capacity evacuation device or perform evacuation for a long time, In the former case, it becomes uneconomical, and in the latter case, the producer decreases.

Therefore, an object of the present invention is to provide an ion implantation apparatus in which the above points are improved.

[Means for solving the problem]

An ion implantation apparatus according to the present invention is a valve that selectively closes a communication portion between an upstream vacuum vessel and two implantation chambers at a branch portion of the vacuum vessel, and is more than a valve body of the vacuum valve. A valve having a light valve body and a non-contact labyrinth portion formed between a peripheral member of the valve body and a fixing member on the nerve container side is provided.

[Action]

When the valve is closed, the conductance decreases in the labyrinth part. Therefore, by providing such a valve, it is possible to prevent the two injection chambers from mutually affecting the degree of vacuum without opening and closing a vacuum valve having a hermetic seal portion due to mechanical contact.

In addition, this valve does not have an airtight seal portion due to mechanical contact, and its valve body is light, so that the load on its supporting portion is light. Therefore, there is almost no possibility of shortening the life and generating dust due to opening and closing.

〔Example〕

FIG. 1 is an enlarged cross-sectional view showing an example of a branch portion of a vacuum vessel in an ion implantation apparatus according to the present invention.
Parts other than the illustration are the same as those in the example of FIG. 4, and reference is made to them. In the following, differences from the conventional example will be mainly described.

In this embodiment, a communication portion between the upstream vacuum vessel 4 and the two injection chambers 12a and 12b, more specifically, a partition plate 6 is provided at the branch portion of the vacuum vessel 4 as described above. A valve 24 for selectively closing the openings 7a and 7b for passing the ion beam 2 (see FIG. 4) is provided.

The valve 24 has a valve body 28 and a labyrinth part 32.

The valve body 28 is thinner and lighter than the valve bodies 10a and 10b of the above-described vacuum valves 8a and 8b, and is attached to a rotary shaft 26 inserted in the vacuum vessel 4 while maintaining airtightness. ,
Thereby, it is inverted by 180 degrees as indicated by arrow A.

The labyrinth part 32 is, in this example, an opening 7a of the partition plate 6.
And 7b, and a ring-shaped movable member 31 attached to the valve body 28 so as to enter in a non-contact manner with a very narrow gap therebetween. It is composed of

Therefore, in this embodiment, for example, when the ion beam 2 is introduced into the implantation chamber 12b and the ions are implanted, the opening 7a side of the partition plate 6 may be closed by the valve 24 as shown in the illustrated example. Of course, the conventional maintenance vacuum valves 8a and 8b may be left open.

By doing so, the labyrinth part 32 around the opening 7a
In this case, conductance is greatly reduced though it is non-contact. As a result, it is possible to prevent a decrease in the degree of vacuum in the injection chamber 12a from affecting the degree of vacuum in the injection chamber 12b without using the vacuum valves 8a and 8b. Therefore, it is not necessary to sufficiently increase the degree of vacuum in the pre-vacuum chambers 16a and 16b as described in the conventional example, and the accompanying reduction in economy and productivity is also eliminated.

Conversely, when ion implantation is performed on the implantation chamber 12a side, the valve 24
The same result as above can be obtained by inverting the valve body 28 to the opening 7b side as shown by a two-dot chain line in the figure.

Moreover, unlike the vacuum valves 8a and 8b, this valve 24 does not have a hermetic seal portion due to mechanical contact such as packing, and the valve body 28 is light, so that the load on the support portion is light, so that Is opened and closed each time the injection chamber 12a and the injection chamber 12b are switched, there is almost no possibility that the life will be shortened or dust will be generated.

FIG. 2 is an enlarged cross-sectional view showing another example of the branch portion of the vacuum vessel in the ion implantation apparatus according to the present invention.

The difference from the example of FIG. 1 will be mainly described. In this embodiment, a valve 34 corresponding to the valve 24 is provided, and an opening 7 is provided immediately upstream of the partition plate 6.
Openings 41 for ion beam passage at positions corresponding to a and 7b
A thin plate 40 having both a and 41b is provided, and the valve body 38 is accommodated in a non-contact manner with a very narrow gap therebetween.

The valve body 38 is thinner and lighter than the valve bodies 10a and 10b of the vacuum valves 8a and 8b, and is supported by a shaft 36, and is rotated as shown by an arrow C (see also FIG. 3). Thereby, the openings 7a and 41a or the openings 7b and 41b are alternatively closed.

In addition, the side closed by the valve body 38 includes the peripheral portion of the valve body 38 and the partition plate 6 and the thin plate as fixing members on the vacuum vessel 4 side.
The labyrinth portion 42 is configured to enter without contact with 40.

Incidentally, the valve body 38 of the valve 34 is driven by, for example, as shown in FIG.
This can be performed by inserting the valve body 38 into the vacuum container 4 through 46 and then rotating the valve body 38 as shown by the arrow C.

Therefore, also in the case of this embodiment, since the conductance around the opening 7a or 7b on the side closed by the valve body 38 is greatly reduced, it is necessary to prevent the injection chambers 12a and 12b from mutually affecting the degree of vacuum. Can be. In addition, since the valve body 38 is light and non-contact, there is almost no possibility of dust generation due to a shortened life due to the opening and closing thereof.

In each of the above embodiments, one valve body 28 or 38
Is moved so that the openings 7a and 7b sides of the partition plate 6 are selectively closed.
The openings 7a and 7b may be alternatively closed by alternately closing them using two valve bodies dedicated to the sides.

〔The invention's effect〕

As described above, according to the present invention, since the valve that selectively closes the communication portion between the upstream vacuum vessel and the two injection chambers is provided, the vacuum valve having the hermetic seal portion by mechanical contact is provided. Without opening and closing, it is possible to prevent the two injection chambers from mutually affecting the degree of vacuum.

In addition, this valve does not have an airtight seal portion due to mechanical contact, and its valve body is light, so that the load on its supporting portion is light. As a result, there is almost no possibility that the opening and closing of the valve will shorten its life and generate dust.

[Brief description of the drawings]

FIG. 1 is an enlarged cross-sectional view showing an example of a branch portion of a vacuum vessel in an ion implantation apparatus according to the present invention. FIG. 2 is an enlarged cross-sectional view showing another example of the branch portion. FIG. 3 is a front view showing an example of a drive mechanism of the valve shown in FIG. FIG. 4 is a cross-sectional view partially showing an example of a conventional ion implantation apparatus. 2 ... Ion beam, 4 ... Vacuum container, 6 ... Partition plate,
8a, 8b: Vacuum valve having hermetic seal by mechanical contact, 12a, 12b: Injection chamber, 24, 34 ... Valve, 28, 38 ...
Valve, 32,42 ... Labyrinth part.

Claims (1)

(57) [Claims] 1. A vacuum vessel for introducing an ion beam is branched into two, and an injection chamber is provided at each end via a vacuum valve having a hermetically sealed portion by mechanical contact. In an ion implantation apparatus adapted to switch and introduce a beam, a valve for selectively closing a communication section between an upstream vacuum vessel and two implantation chambers at a branch portion of the vacuum vessel, An ion having a valve element having a lighter valve element than a valve element of a vacuum valve, and a non-contact labyrinth portion formed between a peripheral portion of the valve element and a fixing member on the vacuum vessel side. Infusion device.