US20120145724A1

US20120145724A1 - Vacuum container

Info

Publication number: US20120145724A1
Application number: US13/315,585
Authority: US
Inventors: Daisuke KOBINATA
Original assignee: Canon Anelva Corp
Current assignee: Canon Anelva Corp
Priority date: 2010-12-14
Filing date: 2011-12-09
Publication date: 2012-06-14
Also published as: JP2012127386A

Abstract

A vacuum container which has a seal member in fitting faces of the vacuum container to be divided into half, has a labyrinth forming device inside the vacuum container in the fitting faces, and a labyrinth forming device has a concave member in which a concave portion is formed, a convex member which has a convex portion arranged to have a slight gap between the inner surface of the concave portion, and a vertically moving mechanism which operates the convex member in a direction close to the concave member.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention
The present invention relates to a vacuum container and, more particularly, the present invention relates to a vacuum container which can use a seal member which can be repeatedly used, and which can be evacuated to an extra-high vacuum.
2. Description of the Related Art
To maintain the interior of a vacuum container to a vacuum area of a high level, a very little leak amount can only be tolerated. Hence, a metal seal (metal O ring) which is a seal member of an opening portion is used.
For example, in case of a vacuum container which is evacuated to the extra-high vacuum of about 10⁻⁷to 10⁻⁹Pa, seal member (metal seal) made of a metal material of a small gas emission speed is used for a seal member of an opening portion (see Japanese Patent Application Laid-Open No. 5-287521).
However, the metal seal plastically deforms, and therefore an exchange of a container with a new one is required to maintain every time the vacuum container is released and has a problem of requiring cost. Hence, it is preferable to use a seal member which can be repeatedly used for a seal member of a vacuum container of an extra-high vacuum.

BRIEF SUMMARY OF THE INVENTION

The present invention is made to solve the above problem, and it is therefore an object of the present invention to provide a vacuum container which can use a seal member which can be repeatedly used, for a seal member of a vacuum container which can be evacuated to an extra-high vacuum area.
A vacuum container which sandwiches a seal member in a fitting face of a divided portion, the vacuum container includes: a gas lead-out path forming device which can form a gas lead-out path which leads gas from the fitting face to an inside of the vacuum container, wherein the gas lead-out path forming device includes: a concave member in which a concave portion is formed; a convex member which includes a convex portion arranged to include a gap between an inner surface of the concave portion; and a driving device which operates one of the convex member and the concave member in a direction close to the other one of the convex member and the concave member, and wherein the gas lead-out path is formed by a gap between the convex member and the inner surface of the concave portion, and is formed only when the driving device arranges one of the convex member and the concave member close to the other one of the convex member and the concave member.
The present invention can use a seal member which can be repeatedly used, for a seal member of a vacuum container of a vacuum processing device which provides an atmosphere of an extra-high vacuum. By this means, it is possible to reduce the number of operation processes of maintaining the vacuum container.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic view of a vacuum processing device according to a first embodiment of the present invention;

FIG. 2 is a schematic view when a vacuum processing device according to the first embodiment of the present invention is released to an air;

FIG. 3 is a pattern diagram illustrating an operation of closing a labyrinth forming device according to the first embodiment of the present invention on a step by step basis; and

FIG. 4 is a sectional view of a labyrinth forming device according to a second embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In addition, members, an arrangement and the like described below are only examples of an embodied present invention and by no means limit the present invention, and it naturally goes without saying that these can be variously changed according to the spirit of the present invention.
Although this description uses an example of a vacuum processing device S (an in-line sputtering film forming device) which has a vacuum container, the present invention is by no means limited to this. A labyrinth forming device mounted on the, present invention is also suitably applicable to, for example, other PVD devices and CVD devices.
FIGS. 1 to 3 are views for explaining a vacuum container according to a first embodiment of the present invention, and FIG. 1 is a schematic view of a vacuum processing device, FIG. 2 is a schematic view when the vacuum processing device is released to the air and FIG. 3 is a pattern diagram illustrating an operation of closing the vacuum processing device on a step by step basis. In addition, part of members are not illustrated to avoid complication of the drawings.
A vacuum processing device S illustrated in FIG. 1 is a vacuum processing device which has a vacuum container 12 an interior of which can be evacuated by a vacuum pump 10, and has the vacuum container 12, a plasma generating device 14 (cathode) arranged in the center of the upper portion of the vacuum container 12, a substrate holder 18 in the center of the lower portion and a power source which supplies power to the plasma generating device 14. A film forming material 16 (target) can be arranged on the plasma generating device 14, and a substrate W can be arranged on the substrate holder 18. The vacuum processing device S deposits film forming substances sputtered from the film forming material 16, on the substrate W arranged on the substrate holder 18 to form a film (perform vacuum processing).
The vacuum container 12 is a metal container which has a nearly parallelepiped rectangular shape the interior of which can be evacuated, and employs a configuration to be divided into a first member 12 a positioned on an upper side and a second member 12 b positioned on a lower side in FIG. 1. A groove 13 is provided in an endless shape all around in fitting faces of the divided portions (opening portions) of the first member 12 a and the second member 12 b. A seal member 20 formed with an O ring made of an elastomer material is arranged to fit to this groove 13. Further, a labyrinth forming device 22 (gas lead-out path forming device) is provided such that, on the vacuum side (inner side) from the fitting faces of the divided portions, a gas lead-out path described below can be formed all around along the inner periphery of the vacuum container 12.
Naturally, a combination of an elastomer material and metal formed to be repeatedly used may be used for the seal member 20. Although the materials of the O ring include, for example, fluorine-contained rubber (FKM), perfluoroelastomer, silicon rubber (VMQ), and ethylene-propylene rubber (EPDM), an example will be described where fluorine-contained rubber is used.
With the present embodiment, although the first member 12 a and the second member 12 b are divided into upper and lower directions, directions and areas to be divided can be adequately changed. For example, a vacuum container may be used in which the first member 12 a and the second member 12 b are divided in right and left directions. Further, the present invention is applicable even when the relationship between the first member 12 a and second member 12 b is the relationship between the vacuum container which has the opening portion, and a hatch-shaped cap which blocks this operation portion.
The labyrinth forming device 22 (gas lead-out path forming device) has: a concave member 23 in which a concave portion 23 a of 1 to 2 mm wide and 5 to 20 mm deep in the cross section is formed; a convex member 25 which has a convex portion 25 a which can be inserted in the concave portion 23 a of the concave member 23; and a vertically moving mechanism 28 which vertically moves the convex member 25. With the present embodiment, the concave member 23 is arranged on the upper side, and the convex member 25 is arranged on the lower side. By moving the convex member 25 by means of the vertically moving mechanism 28 and inserting the convex portion 25 a of the convex member 25 in the concave portion 23 a of the concave member 23, it is possible to form a gas lead-out path (labyrinth passage) of a labyrinth shape which is formed in a gap between the inner surface of the concave portion 23 a and the convex portion 25 a. This gap (predetermined gap) is formed to have a width of about 0.01 to 20 mm and a passage length of several tens of millimeters. When the width of the gas lead-out path is narrower or the passage length is longer, the conductance becomes smaller, so that it is possible to increase the arrival vacuum degree.
The gas lead-out path has a labyrinth shape in which a gas flow passage from the fitting faces toward the vacuum container has concavities and convexities. Further, the concave portion 23 a and the convex portion 25 a are formed in an endless shape along the inner peripheral surface of the vacuum container 12, so that it is possible to form a gas lead-out path without being broken all around in the vacuum container 12 along the fitting faces of the endless shape.
The labyrinth forming device 22 can form the gas lead-out path through which gas emitted from the fitting faces to the inside of the vacuum container 12 passes. That is, gas emitted from the fitting faces to the inside of the vacuum container 12 cannot enter the inside of the vacuum container 12 without passing through the gas lead-out path or the gap between the convex member 25 and the second member 12 b. In addition, most of gas emitted from the fitting faces is outgas from the seal member 20.
The gap between the convex member 25 and the second member 12 b is set to have a width narrower than the gas lead-out path or have a length longer than the gas lead-out path. That is, the gap between the convex member 25 and the second member 12 b is formed to have a conductance smaller than in the gas lead-out path. Consequently, most of gas which enters the inside of the vacuum container 12 from the fitting faces passes through the gas lead-out path. In addition, with the vacuum container 12, the concave member 23 and the first member 12 a are integrally formed, and no gap is formed between the first member 12 a and the concave member 23.
The fitting faces are formed in the divided port ions between the first member 12 a and the second member 12 b, and are formed in an endless shape. Consequently, forming the gas lead-out path in an endless shape all around inside the vacuum container 12 along the fitting faces is also effective. Naturally, a certain degree of an effect can be expected even when the gas lead-out path is formed only at part of the fitting faces. This is because the amount of gas flowing in the inside of the vacuum container 12 from the fitting faces decreases according to the length of the gas lead-out path formed along the fitting faces. The shape of the gas lead-out path to be formed and the length formed opposing the fitting faces (the length formed inside the vacuum container 12 along the fitting faces) are set according to the gas, emission amount from the fitting faces.
Meanwhile, the gas lead-out path (labyrinth passage) of a labyrinth shape refers to a meandering gas lead-out path formed between the inner surface of the concave portion 23 a and the convex portion 25 a. The labyrinth forming device 22 can decrease the conductance of the passage in which gas flows from the portion of the seal member 20 (fitting faces) to the film forming atmosphere (in the vacuum container), and decrease the gas emission speed from the seal member 20 to the film forming atmosphere, to the same level as the seal member made of a metal material. In addition to the meandering passage, the labyrinth passage only needs to be a passage which has a long passage length of a path in which gas flows and which has a decreased conductance.
Further, the labyrinth forming device 22 has a vertically moving mechanism 28 which is a driving device which vertically moves the convex member 25 to place close to the concave member 23. The vertically moving mechanism 28 has a shaft member 29 which moves vertically through the opening 15 formed in the bottom surface of the vacuum container 12, an air cylinder (not illustrated) which is jointed to the shaft member 29 and a bellows tube (not illustrated) which keeps airtight between the shaft member 29 and the air cylinder.
The vertically moving mechanism 28 can vertically drive the convex member 25 of the labyrinth forming device 22 inside the vacuum container 12, and adequately form and release the labyrinth passage. FIG. 2 illustrates the state where the vertically moving mechanism 28 moves the convex member 25 downward, and, in this state, the convex member 25 is not inserted in the inner surface of the concave member 23 and therefore the labyrinth passage is not formed. In addition, a member which is driven by the vertically moving mechanism 28 may be the convex member 25 or the concave member 23, and a member which operates one of the convex member 25 and the concave member 23 in a direction close to the other is applicable to the present invention.
FIG. 3 illustrates an evacuation process for the vacuum container and an operation timing of the vertically moving mechanism.
FIG. 3A illustrates an initial state of the vacuum container 12, and the labyrinth passage is not formed. In addition, in this description, the positional relationship between the convex member 25 and the concave member 23 in which the labyrinth passage is not formed means “the released state of the labyrinth passage”. FIG. 3B illustrates a state where evacuation is performed to a high vacuum after evacuation roughing from a low vacuum to a middle vacuum, and the released state of the labyrinth is maintained. FIG. 3C illustrates a state immediately before vacuum processing such as film formation is performed after the pressure in the vacuum container 12 reaches the film forming processing pressure. That is, vacuum processing is performed in a state where the labyrinth passage is formed.
By controlling the vertically moving mechanism 28 in this way, it is possible to perform evacuation in the released state of the labyrinth passage and form the labyrinth passage after the vacuum degree reaches a predetermined pressure. Consequently, it is possible to prevent the influence on film to/motion by decreasing the gas emission speed from the seal member 20 upon film formation processing while maintaining the evacuation time as in a conventional manner.
Describing the effect of the present invention in more details, it is necessary to decrease the speed at which gas produced from the seal member 20 enters the vacuum container 12 to suppress the decrease of the vacuum degree inside the vacuum container 12. Further, to decrease the speed at which outgas from the seal member 20 enters the vacuum side (in the vacuum container), it is effective to decrease the conductance of gas from a space (in the vacuum container) in which film formation processing is performed, to the seal member 20.
Meanwhile, the conductance is determined according to the width (sectional area) and the length of the gas lead-out path, and the sectional area is small and the conductance can be decreased by providing a long gas lead-out path. Hence, with the present invention, the gas emission speed from the seal member 20 of the vacuum container 12 is decreased in a pseudo manner by forming the labyrinth passage in the gas lead-out path. Consequently, by using the present invention, it is possible to use a seal member which can be repeatedly used as a seal member of the vacuum container which is evacuated to an extra-high vacuum area, so that it is possible to reduce manufacturing cost and the number of operation processes and improve an environment assessment. Further, by forming the labyrinth passage after the vacuum degree reaches a predetermined pressure, it is not necessary to evacuate the inside of a gap of a small conductance and extend an evacuation time.
FIG. 4 is a sectional pattern diagram of a labyrinth forming device according to a second embodiment of the present invention, and is a pattern diagram of the surrounding of the fitting faces and the labyrinth forming device 32. Compared to the above first embodiment, a feature of the present invention lies in the configuration of a labyrinth forming device 32. In addition, members will not be illustrated except for part of members to avoid complication of the drawing, and the same members as in the first embodiment will be assigned to the same reference numerals and will not be described.
Similar to the labyrinth forming device 22 according to the first embodiment, the labyrinth forming device 32 (gas lead-out path forming device) according to the present embodiment is a device in which, on the vacuum side (inner side) from the fitting faces of the divided portions, a gas lead-out path is formed all around along the inner periphery of the vacuum container 12, and has a convex member 35, a concave member 33, a second convex member 37 and a vertically moving mechanism 28. The convex member 35 is integrally formed with the vacuum side of the fitting faces of the first member 12 a, and the concave member 33 is attached to the vertically moving mechanism 28 to move vertically. Further, a second convex member 37 which has the second convex member 37 a is integrally formed on the vacuum side of the fitting faces of the second member 12 b.
The concave member 33 has the concave. portions 33 a and 33 b at two portions, and the second convex portion 37 a is inserted into the concave portion 33 a and the convex portion 35 a is inserted into the concave portion 33 b to form the labyrinth passage. The labyrinth passage according to the present embodiment can be formed between the inner surface of the concave portion 33 a and the convex portion 37 a and between the inner surface of the concave portion 33 b and the convex portion 35 a when the concave member 33 is raised. FIG. 4 illustrates a state where the vertically moving mechanism 28 moves (raises) the concave member 33 upward, and the labyrinth passage is formed.
The labyrinth forming device 32 can also form the labyrinth passage between the second member 12 b and the concave member 33. Although the effect according to the present embodiment is virtually the same as the above first embodiment, it is possible to make the labyrinth forming device 32 more compact than the structure according to the first embodiment.
The present invention can use a seal member which can be repeatedly used, for a seal member of a vacuum container of a vacuum processing device which provides an atmosphere of an extra-high vacuum. By this means, cost to exchange a metal O ring (metal seal) is not required, and the number of operation processes can be reduced, upon maintenance of the vacuum container.

Claims

1. A vacuum container which sandwiches a seal member in a fitting face of a divided portion, the vacuum container comprising:

a gas lead-out path forming device which can form a gas lead-out path which leads gas from the fitting face to an inside of the vacuum container,

wherein the gas lead-out path forming device includes:

a concave member in which a concave portion is formed;

a convex member which includes a convex portion arranged to include a gap between an inner surface of the concave portion; and

a driving device which operates one of the convex member and the concave member in a direction close to the other one of the convex member and the concave member, and

wherein the gas lead-out path is formed by a gap between the convex member and the inner surface of the concave portion, and is formed only when the driving device arranges one of the convex member and the concave member close to the other one of the convex member and the concave member.

2. The vacuum container according to claim 1, wherein the gas lead-out path forming device does not form the gas lead-out path when an interior of the vacuum container is evacuated, and forms the gas lead-out path when the vacuum processing is performed in the vacuum container.

3. The vacuum container according to claim 1, wherein the gas lead-out path forming device forms the gas lead-out path in an endless shape along the fitting face.

4. The vacuum container according to claim 1, wherein the seal member is made of an elastomer material.