JP4203913B2 - Vacuum device - Google Patents

Description

[0001]
[Technical field to which the invention belongs]
The present invention relates to a vacuum apparatus, and more particularly, to a vacuum apparatus that drives a rotating shaft extending into a vacuum chamber from the outside air pressure side. For example, the production of master plates for injection molding of CDs and optical discs requires fine processing that exceeds optical processing means, so that desired information can be obtained by irradiating an electron beam while rotating at high speed in a high vacuum atmosphere. The information recording device used for this is a typical example of a vacuum device. The present invention relates to a vacuum apparatus including a transfer apparatus for attaching and detaching a substrate to and from a film forming apparatus such as a CVD apparatus, a sputtering apparatus, a vacuum deposition apparatus, and an MBE apparatus that require a clean and ultra-high vacuum.
[0002]
The information recording apparatus has a rotating shaft for rotating a workpiece, that is, a plate to be processed in a vacuum chamber. The rotating shaft is supported and supported by an air bearing or the like for high-speed and accurate rotation. It is customary. For this reason, this kind of apparatus drives the rotating shaft extended in the vacuum chamber from the external pressure side.
[0003]
If the rotating shaft extends from the external pressure side to the vacuum chamber, it is necessary to seal that portion. The present invention relates to a vacuum apparatus that drives a rotating shaft extending into a vacuum chamber from the outside air pressure side, and more particularly to a sealing technique in the case of a biaxial coaxial rotating shaft.
[0004]
[Prior art]
Conventionally, in a vacuum apparatus such as a CVD apparatus, a differential exhaust method or an intermediate chamber exhaust method is very commonly used. The same concept can be applied to the magnetic fluid seal, and is described in, for example, Japanese Patent Application Laid-Open Nos. 09-215917 and 09-089120. However, the above known means cannot solve the problem for the inner seal portion in the case of two axes.
[0005]
[Problems to be solved by the invention]
In other words, in the prior art, the introduction of uniaxial power was effective, but in the case of two shafts, the oil in the bearing and magnetic fluid seal entered the vacuum chamber from the inner seal shaft, resulting in a cleanliness and ultrahigh power. There was a problem in achieving the vacuum. Accordingly, an object of the present invention is to eliminate the above-mentioned problems. In a vacuum apparatus having a coaxial magnetic fluid seal having two or more axes, the vacuum environment in the apparatus is caused by desorbed gas from a bearing or magnetic fluid. An object of the present invention is to provide an apparatus that can be kept clean and in an ultra-high vacuum so as not to be affected.
[0006]
[Means for Solving the Problems]
Therefore, in order to solve the above-described problems, the present invention is to provide a vacuum apparatus that can obtain a sufficient intermediate chamber exhaust effect even when the shaft is rotating, by forming a through hole in the outer shaft .
[0007]
In such a vacuum device, the rotating shaft extending into the vacuum chamber is driven from the outside air pressure side to process the rotating object in a vacuum atmosphere. By providing a vacuum device that closes the gap around the rotation axis between the vacuum chamber and the external air pressure side, the vacuum chamber must have a high vacuum state necessary for processing with an electron beam or an ion beam. Becomes easier.
[0008]
This vacuum device is provided with a magnetic fluid seal to close the gap around the rotation axis. However, since this magnetic fluid seal is disposed between the vacuum chamber and the intermediate chamber, the magnetic fluid seal has an external pressure resistance. It can be smaller than atmospheric pressure. This makes it possible to reduce the thickness of the magnetic fluid seal as compared with the case where the vacuum chamber is sealed from the external pressure only with the magnetic fluid seal, and thus the rotational resistance of the rotating shaft can be reduced. As a result, it becomes easier to drive the rotary shaft at a high speed.
[0009]
Further, an intermediate chamber 10 is formed between the magnetic fluid seal and the external pressure. This exhaust is provided with a large number of exhaust pipes 10a and exhausted to a high vacuum, so that the target vacuum chamber A is cleaned. And a high vacuum is achieved.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of a main part of an embodiment according to the present invention, and FIG. 2 is an explanatory view of the main part of the same part. In this embodiment, an intermediate chamber flange 6 is mounted under the vacuum chamber lower wall 7 of the vacuum chamber A and on the outer circumferences of the rotary shafts 1 and 2, and a bearing flange 5 is mounted at the lower portion thereof. The space between the vacuum chamber lower wall 7 and the outer shaft 2 is a seal portion 11, and the space between the inner shaft 1 and the outer shaft 2 is a seal portion 12.
[0011]
Further, the inner shaft 1 sealed by the inner shaft magnetic fluid seal 3 and driven by the lower motor M is made to correspond to the first arm 1a, and sealed by the outer shaft magnetic fluid seal 4 and driven by the lower motor M. By making the outer shaft 2 corresponding to the second arm 2a of the robot shaft, a substrate transfer robot to various film forming apparatuses having clean and ultrahigh vacuum characteristics is configured. The inner shaft magnetic fluid seal 3 and the outer shaft magnetic fluid seal 4 are disposed between the upper and lower bearings 8.
[0012]
That is, the two rotating shafts constituting the robot shaft of the present apparatus are composed of an inner shaft 1 and an outer shaft 2 that are rotationally driven by a motor M, and a vacuum chamber via a flange 6 that forms an intermediate chamber 10. A vacuum device C in which A and an external air pressure side B are connected by a seal portion 11 and a seal portion 12, and has a structure in which a plurality of through holes 2 b are formed in an outer cylindrical outer shaft 2. At the same time, the outer cylindrical outer shaft 2 has a structure in which an enlarged inner portion is formed by partially increasing the inner diameter. The intermediate chamber 10 is connected to an exhaust pipe 10a for air suction. The “outside air pressure” described above is typically atmospheric pressure, but it also corresponds to a state of quasi-atmospheric pressure that has been pressurized or reduced.
[0013]
As another example (not shown), when using a substrate holder (substrate susceptor) equipped with a plurality of substrates in a CVD apparatus or a vacuum deposition apparatus, the outer shaft is used as a substrate in order to improve the film thickness uniformity. Revolution-spinning type film formation may be possible by using the holder for rotation and using the inner shaft for rotation of individual substrates via gears or the like.
[0014]
In the above embodiment, the case of the biaxial rotating shaft has been described. However, the same effect can be expected even when the rotating shaft has three or more axes.
[0015]
【The invention's effect】
The present invention is a vacuum apparatus equipped with a coaxial magnetic fluid seal of two or more axes, and can be kept clean and ultra-high vacuum by preventing the vacuum chamber from being affected by desorption gas from bearings and magnetic fluid. There is an effect .
[0016]
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a main part of an embodiment according to the present invention (cross-sectional view of a portion C in FIG. 2).
FIG. 2 is an explanatory diagram of a main part of an embodiment according to the present invention.
[Explanation of symbols]
A ... Vacuum chamber B ... External pressure side C ... Vacuum apparatus M ... Motor 1 ... Inner shaft (rotary shaft)
1a ... 1st arm 2 ... Outer shaft (rotating shaft)
2a ... 2nd arm 2b ... through hole 3 ... inner shaft magnetic fluid seal 4 ... outer shaft magnetic fluid seal 5 ... bearing flange 6 ... intermediate chamber flange 7 ... vacuum chamber Lower wall 8 ・ ・ ・ Bearing 9 ・ ・ ・ Expanded part 10 ・ ・ Intermediate chamber 10 a ・ ・ Exhaust pipe 11 ・ ・ Seal part 12 ・ ・ Seal part

Claims (1)

An intermediate chamber flange 6 is mounted below the vacuum chamber lower wall 7 of the vacuum chamber A, and a bearing flange 5 is mounted below the intermediate chamber flange 6. The rotary shaft 1 extends into the vacuum chamber A and is arranged biaxially. , 2 are driven from the external air pressure side B, an intermediate chamber 10 is formed between the intermediate chamber flange 6 and the rotary shaft 2, and the vacuum chamber A and the external air pressure side are further formed. A vacuum device C provided with an inner shaft magnetic fluid seal 3 and an outer shaft magnetic fluid seal 4 that block the respective gaps around the rotation shafts 1 and 2 across B, and a cylindrical type outside the inner shaft magnetic fluid seal 3 A vacuum apparatus characterized in that a plurality of through-holes 2b are formed in the outer shaft 2, and air can be sucked from the through-holes 2b through the intermediate chamber 10.

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