Sealing mechanism for sealing a vacuum chamber

• US 20040119240A1
• Filed: 12/11/2003
• Published: 06/24/2004
• Est. Priority Date: 10/26/1998
• Status: Active Grant

• Current Assignee: Teijin Seiki Co., Ltd. (Nabtesco Corporation)
• Original Assignee: Teijin Seiki Co., Ltd. (Nabtesco Corporation)
• Inventors: Hashimoto, Akio
• Granted Patent: US 7,246,800 B2
• Time in Patent Office: Days
• US Class Current: 277/432
• CPC Class Codes: F16J 15/006 with division of the pressure F16J15/44 takes precedence
• CPC Class Codes: F16J 15/3212 with metal springs
• CPC Class Codes: F16J 15/3236 with at least one lip for each surface, e.g. U-cup packings
• CPC Class Codes: H01J 2237/166 Sealing means
• CPC Class Codes: H01J 37/32431 Constructional details of the reactor
• CPC Class Codes: H01L 21/67126 Apparatus for sealing, encapsulating, glassing, decapsulating or the like processes H01L23/02, H01L23/28
• CPC Class Codes: Y10S 277/913 Seal for fluid pressure below atmospheric, e.g. vacuum
• CPC Class Codes: Y10S 277/918 Seal combined with filter or fluid separator
• CPC Class Codes: Y10S 277/927 Seal including fluid pressure differential feature

Abstract

A sealing mechanism comprises a support member forming part of the semiconductor producing apparatus which has a vacuum chamber, a rotation shaft rotatably received in the support member, and at least three seal rings axially spaced apart from each other between the support member and the rotation shaft to form a first fluid chamber close to the atmosphere and a second fluid chamber close to the vacuum chamber. The first fluid chamber is vacuumized to have a first pressure, and the second fluid chamber is also vacuumized to have a second pressure which is lower than the first pressure. The first and second fluid chambers work together to enhance the sealing performance of the sealing mechanism.

Claims

1. A sealing mechanism for sealing a vacuum chamber formed in the semiconductor producing apparatus, comprising:

a rotation shaft driven to be rotatable around its own axis and having an outer surface in the form of a cylindrical shape;

a support member intervening between said vacuum chamber and the atmosphere and rotatably supporting said rotation shaft to have said rotation shaft received therein, said support member having an inner surface in the form of a cylindrical hollow shape and first and second axial ends respectively extending in the atmosphere and said vacuum chamber, said inner surface of said support member being larger in diameter than said outer surface of said rotation shaft, said support member being formed with a first fluid passageway having a first end and a second end and a second fluid passageway having a first end and a second end open toward said vacuum chamber;

first and second seal rings positioned between said rotation shaft and said support member in axially spaced-apart relationship with each other to hermetically seal the gap between said rotation shaft and said support member under the state that said first seal ring is located in the neighborhood of said first axial end of said support member and remote from said second axial end of said support member and that said second seal ring is located in the neighborhood of said second axial end of said support member and remote from said first axial end of said support member, said rotation shaft, said support member, and said first and second seal rings collectively forming a first fluid chamber held in communication with said first fluid passageway through said first end of said first fluid passageway;

an air sucking unit having a port held in communication with said second end of said first fluid passageway to maintain the pressure of said first fluid passageway at a level between the atmospheric pressure and the inner pressure of said vacuum chamber,

a third seal ring positioned between said rotation shaft and said support member in axially spaced-apart relationship with said second seal ring between said second seal ring and the extension plane radially inwardly extending and flush with said second axial end of said support member to hermetically seal the gap between said rotation shaft and said support member, said rotation shaft, said support member, and said second and third seal rings collectively forming a second fluid chamber held in communication with said second fluid passageway through said first end of said second fluid passageway; and

a fluid filter disposed on the portion of said support member exposed to said vacuum chamber to cover said second end of said second fluid passageway.

2. A sealing mechanism as set forth in claim 1 in which said support member is formed with an additional first fluid passageway and an additional second fluid passageway.

5. A sealing mechanism as set forth in claim 1 which further comprises stop means for stopping said first to third seal rings from moving toward said vacuum chamber with respect to said rotation shaft and said support member.

6. A sealing mechanism as set forth in claim 5 in which said stop means is constituted by first to third rings which are fastened selectively to said rotation shaft and said support member to respectively stop said first to third seal rings from moving toward said vacuum chamber.

7. A sealing mechanism as set forth in claim 1 in which said outer surface of said rotation shaft and said inner surface of said support member are coated with a tetrafluoroethylene layer.

8. A sealing mechanism as set forth in claim 1 in which each of said first to third seal rings comprises an annular retaining member formed with an annular groove, and an annular spring member tightly received in said annular groove and retained by said annular retaining member to resiliently bias said annular retaining member to expand radially outwardly.

9. A sealing mechanism as set forth in claim 8 in which said annular retaining member is made of a resilient material.

10. A sealing mechanism as set forth in claim 9 in which said annular retaining member is made of rubber.

11. A sealing mechanism as set forth in claim 9 in which said annular retaining member is made of synthetic resin.

12. A sealing mechanism as set forth in claim 8 in which said annular spring member is made of a metal.

13. A sealing mechanism as set forth in claim 8 in which each of said annular spring members of said first and second seal rings is made of a strip in the form of a helical shape.

14. A sealing mechanism as set forth in claim 13 in which said annular spring members of said first and second seal rings are covered by said annular retaining members of said first and second seal rings respectively.

15. A sealing mechanism as set forth in claim 14 in which each of said first and second seal rings has a center axis passing therethrough and is of a circular cross-section taken on the plane perpendicular to said center axis.

16. A sealing mechanism as set forth in claim 14 in which each of said first and second seal rings has a center axis passing therethrough and is of a triangular cross-section taken on the plane perpendicular to said center axis.

17. A sealing mechanism as set forth in claim 8 in which said third seal ring has a center axis passing therethrough and is of a channel-shaped cross-section taken on the plane perpendicular to said center axis.

18. A sealing mechanism as set forth in claim 17 in which said annular groove of third seal ring has an end open toward said second fluid chamber.

3. A sealing mechanism for sealing a vacuum chamber formed in the semiconductor producing apparatus, comprising:

a first rotation shaft driven to be rotatable around its own axis and having an outer surface in the form of a cylindrical shape;

a second rotation shaft driven to be rotatable around its own axis and rotatably receiving therein said first rotation shaft, said second rotation shaft having an inner surface in the form of a cylindrical hollow shape, first and second axial ends respectively extending in the atmosphere and said vacuum chamber, and an outer surface in the form of a cylindrical shape, said inner surface of said second rotation shaft being larger in diameter than said outer surface of said first rotation shaft, said second rotation shaft being formed with a first fluid passageway having first and second ends respectively open at the inner and outer surface of said second rotation shaft and a second fluid passageway having first and second ends respectively open at the inner and outer surface of said second rotation shaft;

a support member intervening between said vacuum chamber and the atmosphere and rotatably supporting said second rotation shaft to have said second rotation shaft received therein, said support member having an inner surface in the form of a cylindrical hollow shape and first and second axial ends respectively extending in the atmosphere and said vacuum chamber, said inner surface of said support member being larger in diameter than said outer surface of said second rotation shaft, said support member being formed with a third fluid passageway having a first end and a second end and a fourth fluid passageway having a first end and a second end open toward said vacuum chamber;

first and second seal rings positioned between said first and second rotation shafts in axially spaced-apart relationship with each other to hermetically seal the gap between said first and second rotation shafts under the state that said first seal ring is located in the neighborhood of said first axial end of said second rotation shaft and remote from said second axial end of said second rotation shaft and that said second seal ring is located in the neighborhood of said second axial end of said second rotation shaft and remote from said first axial end of said second rotation shaft, said first and second rotation shafts and said first and second seal rings collectively forming a first fluid chamber held in communication with said first fluid passageway through said first end of said first fluid passageway;

a third seal ring positioned between said first and second rotation shafts in axially spaced-apart relationship with said second seal ring between said second seal ring and extension plane radially inwardly extending and flush with said second axial end of said second rotation shaft to hermetically seal the gap between first and second rotation shafts, said first and second rotation shafts and said second and third seal rings collectively forming a second fluid chamber held in communication with said second fluid passageway through said first end of said second fluid passageway;

fourth and fifth seal rings positioned between said second rotation shaft and said support member in axially spaced-apart relationship with each other to hermetically seal the gap between said second rotation shaft and said support member under the state that said fourth seal ring is located in the neighborhood of said first axial end of said support member and remote from said second axial end of said support member and that said fifth seal ring is located in the neighborhood of said second axial end of said support member and remote from said first axial end of said support member, said second rotation shaft, said support member, and said fourth and fifth seal rings collectively forming a third fluid chamber held in communication with said first fluid passageway through said second end of said first fluid passageway and said third fluid passageway through said first end of said third fluid passageway;

an air sucking unit having a port held in communication with said second end of said third fluid passageway to maintain the pressure of said third fluid passageway at a level between the atmospheric pressure and the inner pressure of said vacuum chamber;

a sixth seal ring positioned between said second rotation shaft and said support member in axially spaced-apart relationship with said fifth seal ring between said fifth seal ring and the extension plane radially inwardly extending and flush with said second axial end of said support member to hermetically seal the gap between said second rotation shaft and said support member, said second rotation shaft, said support member, and said fifth and sixth seal rings collectively forming a fourth fluid chamber held in communication with said second fluid passageway through said second end of said second fluid passageway and said fourth fluid passageway through said first end of said fourth fluid passageway; and

a fluid filter disposed on the portion of said support member exposed to said vacuum chamber to cover said second end of said fourth fluid passageway.

4. A sealing mechanism as set forth in claim 3 in which said second rotation shaft is formed with an additional first fluid passageway and an additional second fluid passageway, and said support member is formed with an additional third fluid passageway and an additional fourth fluid passageway.

19. A sealing mechanism as set forth in claim 3 which further comprises stop means for stopping said first to third seal rings from moving toward said vacuum chamber with respect to said first and second rotation shafts, and said fourth to sixth seal rings from moving toward said vacuum chamber with respect to said second rotation shaft and said support member.

20. A sealing mechanism as set forth in claim 19 in which said stop means is constituted by first to third rings which are fastened selectively to said first and second rotation shafts to respectively stop said first to third seal rings from moving toward said vacuum chamber, and fourth to sixth rings which are fastened selectively to said second rotation shaft and said support member to respectively stop said fourth to sixth seal rings from moving toward said vacuum chamber.

21. A sealing mechanism as set forth in claim 3 in which said outer surface of said first rotation shaft, said inner surface of said second rotation shaft, said outer surface of said second rotation shaft, and said inner surface of said support member are coated with a tetrafluoroethylene layer.

22. A sealing mechanism as set forth in claim 3 in which each of said first to sixth seal rings comprises an annular retaining member formed with an annular groove, and an annular spring member tightly received in said annular groove and retained by said annular retaining member to resiliently bias said annular retaining member to expand radially outwardly.

23. A sealing mechanism as set forth in claim 22 in which said annular retaining member is made of a resilient material.

24. A sealing mechanism as set forth in claim 23 in which said annular retaining member is made of rubber.

25. A sealing mechanism as set forth in claim 23 in which said annular retaining member is made of synthetic resin.

26. A sealing mechanism as set forth in claim 22 in which said annular spring member is made of a metal.

27. A sealing mechanism as set forth in claim 22 in which each of said annular spring members of said first, second, fourth, and fifth seal rings is made of a strip in the form of a helical shape.

28. A sealing mechanism as set forth in claim 27 in which said annular spring members of said first, second, fourth, and fifth seal rings are covered by said annular retaining members of said first, second, fourth, and fifth seal rings respectively.

29. A sealing mechanism as set forth in claim 28 in which each of said first, second, fourth, and fifth seal rings has a center axis passing therethrough and is of a circular cross-section taken on the plane perpendicular to said center axis.

30. A sealing mechanism as set forth in claim 28 in which each of said first, second, third, and fourth seal rings has a center axis passing therethrough and is of a triangular cross-section taken on the plane perpendicular to said center axis.

31. A sealing mechanism as set forth in claim 22 in which each of said third and sixth seal rings has a center axis passing therethrough and is of a channel-shaped cross-section taken on the plane perpendicular to said center axis.

32. A sealing mechanism as set forth in claim 31 in which said annular groove of third seal ring has an end open toward said second fluid chamber and said annular groove of sixth seal ring has an end open toward said fourth fluid chamber.