JP2005249079A - Sealing unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sealing unit, adjusting its position to a chamber and having excellent durability. <P>SOLUTION: Neither a gasket nor an O-ring is provided between a flange part 11b and a chamber 1, whereby the flange part 11b can be fixed to an arbitrary position of the wall surface of the chamber 1, so that the position of a rotating shaft 2 can be easily adjusted. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a movable member that extends between the inside and the outside of a vacuum chamber, such as a semiconductor manufacturing apparatus, and a seal unit that seals between the vacuum chamber.

  In a semiconductor manufacturing apparatus or the like, a workpiece is placed on a stage and moved to process in a process chamber maintained in a vacuum or a special gas atmosphere. Here, when a positioning device including a drive source is provided in the process chamber, the hermeticity with the outside of the process chamber is maintained, so that a vacuum or a special gas atmosphere can be maintained relatively easily.

  However, when a positioning device including a drive source is provided in the process chamber, the process chamber itself becomes large, and it takes a long time to set the inside of the process chamber at a predetermined pressure, or a large amount of special gas that fills the inside of the process chamber is required. Or the maintenance of the positioning device is difficult.

On the other hand, when the volume of the process chamber is minimized, the above-described problem is solved, but a configuration for driving a table on which a workpiece provided in the process chamber is mounted from the outside of the process chamber is required. . In one of such configurations, a shaft body extending between the inside of the process chamber and the outside is provided through an opening formed in the wall of the housing communicating with the process chamber, and the shaft body is attached to the housing. On the other hand, there are some which drive the table inside the process chamber from the outside of the process chamber by relative movement or rotation. However, in such a configuration, a seal unit that seals between the chamber wall surface covering the process chamber and the moving shaft is required. Such a seal unit is described in Patent Document 1.
JP-A-4-321882

  However, in the seal unit of Patent Document 1, there is a minute gap between the wall surface of the chamber and the flange of the seal unit. Therefore, if no measures are taken, the atmosphere enters the vacuum process chamber through the gap. For example, the atmosphere in the process chamber may be impaired. Although there is no description in Patent Document 1, generally, in such a case, a gasket or an O-ring is interposed between the wall surface of the chamber and the flange of the seal unit.

  Here, in order to perform fine drawing in the semiconductor manufacturing process or the like, the movable member and the chamber need to be positioned with high accuracy. However, in general, when a non-reusable gasket is used to seal between the wall surface of the chamber and the flange of the seal unit, there is a problem that positioning adjustment after installation cannot be performed. On the other hand, when the space between the wall surface of the chamber and the flange of the seal unit is sealed using the O-ring, the flange can be relatively displaced with respect to the chamber even after the attachment, but due to the elasticity of the O-ring. There is a problem that the flange is displaced and fine adjustment is difficult. Further, when the process chamber is maintained in a high temperature atmosphere, the wall surface of the chamber becomes high temperature, so that the heated O-ring may be altered and the sealing characteristics may be deteriorated. When the temperature of the process chamber is suppressed in order to prevent the O-ring from being deteriorated, there arises a problem that processing that can be performed in the process chamber is limited.

  SUMMARY OF THE INVENTION In view of the above-described problems of the prior art, an object of the present invention is to provide a seal unit that can be adjusted in position with respect to a chamber and has excellent durability.

In order to achieve the above object, the sealing unit of the present invention comprises:
In a seal unit that penetrates through an opening formed in the wall surface of the chamber and extends between the inside and the outside of the chamber and a seal between the opening,
A housing attached to the wall of the chamber;
Sealing means for sealing between the housing and the movable member;
Further, a groove formed on at least one of the wall surface of the chamber and the surface of the housing facing the chamber so as to surround the opening, and a passage communicating the space in the groove and an external exhaust pump. It is formed.

  The seal unit of the present invention is a seal unit that penetrates through an opening formed in a wall surface of the chamber and extends between the inside and the outside of the chamber and the seal unit. A housing attached to the wall surface of the chamber; and a sealing means for sealing between the housing and the movable member; and further, the wall surface of the chamber and the surface of the housing facing the chamber so as to surround the opening And a passage communicating with the space in the groove and an external exhaust pump are formed, and by sucking the gas in the groove through the passage, Sealing between the chamber and the seal unit can be realized without using a gasket or an O-ring as in the prior art, and the external exhaust pump is stopped. In the state, the relative displacement between the sealing unit and the chamber for can be easily, the positioning of the movable member and the chamber can be carried out easily and precisely.

  Furthermore, if the sealing means is an exhaust seal and the external exhaust pump is shared with the exhaust seal, the cost can be kept low. However, the exhaust pump for the sealing means and the exhaust pump for sucking the groove may be provided separately.

  Furthermore, the sealing means is preferably a magnetic fluid seal. Since the magnetic fluid is also described in Patent Document 1, details are not described below.

  Furthermore, it is preferable to have a bearing that supports the movable member with respect to the housing.

  The exhaust seal used in this specification refers to, for example, exhausting a gas that is between the throttles such as a minute gap between two opposing surfaces through a differential pressure chamber provided between the two surfaces. In a non-contact state, it functions to keep the atmosphere (for example, atmospheric pressure and high vacuum) on both sides of the opposite surface in a constant state. In the embodiments described below, a member having an exhaust surface is referred to as an exhaust seal.

  Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram of a seal unit 10 according to a first embodiment of the present invention. In FIG. 1, a chamber 1 having a process chamber P inside has an opening 1a. A rotary shaft 2 that is a movable member is inserted through the opening 1a. Although not shown, the end of the rotating shaft 2 in the chamber 1 (the right end in the figure) is attached with, for example, a ball screw or a workpiece to be processed in the process chamber. (Left end in the figure) is connected to a rotational drive source. In addition, the rotating shaft 2 has the enlarged diameter part 2a in the axial center.

  The seal unit 10 includes a housing 11 that encloses the rotary shaft 2. The housing 11 has a cylindrical main body 11a and a flange portion 11b extending in a radial direction from one end (right end in the figure) of the main body 11a. The flange portion 11b is attached to the wall surface of the chamber 1 so that the position thereof can be adjusted using a bolt (not shown). A circumferential groove 11c is formed on the surface of the flange portion 11b facing the wall surface of the chamber 1 so as to surround the opening 1a.

  Inside the housing 11, a differential pressure chamber 11d having an annular space is formed so as to surround the rotary shaft 2. The differential pressure chamber 11d is connected to an external exhaust pump P1 through a passage 11e communicating with the outer periphery and a pipe T attached to the housing 11. The passage 11e is connected to a passage 11f that is formed in the housing 11 and communicates with the circumferential groove 11c. Therefore, the circumferential groove 11c is also connected to the external exhaust pump P1 via the passages 11f and 11e and the pipe T. Yes.

  A bearing unit 12 is fixed to the end of the housing 11. The bearing unit 12 includes a cylindrical holder 12a attached to the housing, and two angular contact bearings 12b and 12b that rotatably support the rotary shaft 2 with respect to the holder 12a. The outer rings of the angular contact bearings 12b and 12b are fixed to the holder 12a by a screw member 12c that is screwed into the holder 12a. It is fixed to the rotary shaft 2 by a screw member 12d that is screwed to the rotary shaft 2 in a state where it is in contact and preloaded.

  In the present embodiment, a negative pressure is applied to the process chamber P in the chamber 1, a ball screw or a work to be processed is attached to the tip of the rotary shaft 2, and a rotational drive source disposed outside the process chamber P Thus, rotational driving can be performed. At this time, the air that enters the differential pressure chamber 11d, which is an exhaust seal, from the bearing unit 12 side is sucked by the external exhaust pump P1, and therefore passes through a gap between the rotary shaft 2 and the housing 11 and then passes through the process chamber. Intrusion into P is suppressed. On the other hand, the air that enters the circumferential groove 11c from between the flange portion 11b and the wall surface of the chamber 1 is also sucked by the external exhaust pump P1, so that it can pass through the gap between the two and enter the process chamber P. It is suppressed. In this case, since it is not necessary for the flange portion 11b and the wall surface of the chamber 1 to be completely in close contact with each other, the processing of the chamber 1 and the flange portion 11 is facilitated, and the sealing performance does not deteriorate even if there is a small scratch. And storage becomes easy. Further, since an O-ring or the like is not used to ensure a vacuum atmosphere in the process chamber P, the process chamber P can be heated to a higher temperature than in the case of use, and the range of possible processing is expanded.

  By the way, when performing a highly accurate process in the process chamber P, positioning of the chamber 1 and the rotating shaft 2 becomes important. Since the rotary shaft 2 is supported by angular contacts 12 b and 12 b fixed to the housing 11, when the rotary shaft 2 is positioned with respect to the chamber 1, the entire housing 11 moves relative to the chamber 1. I have to let it. According to the present embodiment, since neither a gasket nor an O-ring is provided between the flange portion 11b and the chamber 1, the flange portion 11b can be fixed at an arbitrary position with respect to the wall surface of the chamber 1, Thereby, the position adjustment of the rotating shaft 2 can be easily performed.

  FIG. 2 is a schematic configuration diagram of a seal unit 10 ′ according to the second embodiment. The seal unit 10 ′ of the present embodiment is different from the embodiment of FIG. 1 in that a magnetic fluid seal 13 is provided between the differential pressure chamber 11 d and the bearing unit 12. The magnetic fluid seal 13 includes a magnetic member disposed on the housing 11 side and a magnetic fluid disposed between the housing 11 and the rotating shaft 2. Since the other configuration is the same as that of the embodiment of FIG.

  According to the present embodiment, since the magnetic fluid seal 13 is provided in addition to the exhaust seal, it is not necessary to increase the number or capacity of the exhaust pumps as much as it is not necessary to increase the number of exhaust stages. Further, in comparison with the case of only the non-contact type exhaust seal, the inflow amount of air or the like from the outside in an emergency such as an emergency stop of the exhaust pump can be suppressed.

  The present invention has been described above with reference to the embodiments. However, the present invention should not be construed as being limited to the above-described embodiments, and can be modified or improved as appropriate. For example, a shim or the like for angling the rotary shaft 2 with respect to the chamber 1 may be interposed between the wall surface of the chamber 1 and the flange portion 11 b of the seal unit 10. Further, the circumferential groove surrounding the opening 1 a may be provided on the wall surface of the chamber 1.

  Further, as the sealing means for sealing between the rotary shaft 2 and the housing 11, only the exhaust seal and the case where the exhaust seal and the magnetic fluid seal are used together are shown, but only the magnetic fluid seal is used as the sealing means. May be. Further, the number of exhaust seals (the number of differential pressure chambers) may be plural. Moreover, although the case where a rotating shaft is used as a movable member has been shown, the present invention can also be applied to a member that moves in the axial direction (in this case, not limited to a cylindrical shape) or a movable member that rotates and moves in the axial direction. It is. The bearing for supporting the movable member on the housing can be changed to an appropriate one.

It is a schematic structure figure of seal unit 10 concerning a 1st embodiment. It is a schematic block diagram of the seal unit 10 'concerning 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Chamber 2 Rotating shaft 10, 10 'Seal unit 11 Housing 12 Bearing unit 13 Magnetic fluid seal

Claims (4)

In a seal unit that penetrates through an opening formed in the wall surface of the chamber and extends between the inside and the outside of the chamber and a seal between the opening,
A housing attached to the wall of the chamber;
Sealing means for sealing between the housing and the movable member;
Further, a groove formed on at least one of the wall surface of the chamber and the surface of the housing facing the chamber so as to surround the opening, and a passage communicating the space in the groove and an external exhaust pump. A sealing unit characterized by being formed.   The seal unit according to claim 1, wherein the sealing unit is an exhaust seal, and the external exhaust pump is shared with the exhaust seal.   The seal unit according to claim 1, wherein the sealing means is a magnetic fluid seal. The seal unit according to claim 1, further comprising a bearing that supports the movable member with respect to the housing.

Images