JPS60261302A - Article conveyor in high vacuum - Google Patents

Abstract

PURPOSE:To obtain an article conveyor for a high vacuum device having no slide or friction by utilizing levitating and driving actions by magnetism for a conveying mechanism. CONSTITUTION:A conveying case 18 for conveying an article 17 is formed of a nonmagnetic material in a T-shaped sectional shape, a permanent magnet 22 for levitating and aligning is provided, and a conductor plate 23 formed of a nonmagnetic metal material is provided at a vertical leg as the secondary element of a linear motor. On the other hand, a rail 19 for levitating and guiding the case is formed by a permanent magnet, and a levitating horizontal section 19a and an aligning vertical section 19b are provided. Further, a recess 25 is formed on a conveying tube 5 in a departing zone to provide a coil mounting space 26, and a supporting plate 27 for mounting a coil 24 forming the primary side of the linear motor is disposed in the space 26.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to an article conveying device in a high vacuum.

In recent years, high vacuum atmospheres have come to be widely used for surface treatment and purification of semiconductor devices and the like. In addition, ultrahigh vacuum is widely used in research facilities in energy-related fields and physics fields, such as nuclear fusion experimental reactors and accelerators.

In high-vacuum equipment, equipment, facilities, etc. (herein referred to collectively as high-vacuum equipment) that operate in such a high-vacuum atmosphere, the vacuum width must be maintained at all altitudes within a closed space that is shielded or shut off from the outside world. various equipment, parts, etc. in a closed space.
There are many cases where it is necessary to remotely control instruments, etc. from outside the device. For example, when manufacturing semiconductors using cutting-edge technology, it is necessary to consistently receive and receive wafers during each processing and purification process in a high vacuum atmosphere, and there is an increasing demand for transport equipment for this purpose. There is.

(Problems to be Solved by the Invention) When constructing an article conveying device that performs the required operations in a high vacuum, it is necessary to eliminate as much as possible not only sliding contact but also rolling contact. be. The reason for this is that when there are rolling or sliding contact parts, wear due to friction generates fine dust, which contaminates the vacuum atmosphere and prevents the high vacuum equipment from performing its intended function. This is because

In addition, in the working atmosphere of such high vacuum equipment, there is a problem in that since the lubrication effect is insufficient, seizure of sliding and rolling parts often occurs, making it difficult to expect smooth and stable operation of the equipment.

j (Purpose of Invention 0) The present invention has been made in view of the above-mentioned points, and provides a sliding system by utilizing magnetic levitation action and driving action in an operating mechanism in a high vacuum device, particularly in a transfer or conveyance mechanism. It is an object of the present invention to provide an article conveying device for a high vacuum device that has no moving or frictional parts.

(Structure of the Invention) An article conveying device for a high vacuum device according to the present invention includes a conveying tube having a conveying passage inside thereof that is maintained at a predetermined high vacuum, and a conveying pipe that holds an article to be conveyed and has a long length inside the conveying passage. A transport case made of a non-magnetic material that can be moved in a direction, a device that levitates and supports the transport case within a transport path and guides it along the transport path, and a linear motor that applies a driving force to the transport case, The floating support guide device extends along the conveyance path and has a permanent magnet orbit provided in the conveyance path, and a permanent magnet for levitation support and alignment provided in the conveyance case because it acts magnetically repulsively with the permanent magnet of this orbit. The primary side of the linear motor is provided only in the starting zone and deceleration zone of a plurality of stations located apart along the conveyance path, and the linear motor 2 is provided in the conveyance case. The structure is such that acceleration and deceleration actions are applied to the next armature in each of the acceleration and deceleration zones, and the transport case is moved between stations spaced apart from each other.

(Example) The invention will now be explained with reference to the drawings.

The drawings show an example in which the present invention is implemented in a high-vacuum semiconductor device for manufacturing semiconductors in a high-vacuum atmosphere, and in the illustrated example,
A transport path or space 4' extending along the growth chamber 1, analysis chamber 2 and processing chamber 8 which are sequentially provided in the processing line?
r It is provided by a conveying pipe 5 made of non-magnetic material such as niostenite stainless steel or aluminum alloy, and this conveying pipe 5 is connected to each chamber 1.2 and 8 by branch pipes 6, 7 and 8, respectively, and electromagnetic The handle 10 with the electromagnetic chuck operated by other means is connected to the branch pipe 6.7.
For example, the end plates 12' to 14' of the operation chambers 12 to 14 connected to the opposite side of the conveying pipe 6 on the same line as the
1+ are hermetically connected via bellows 15, and the handle 10 is operated electromagnetically, mechanically, or manually from the outside to be conveyed into the conveyance path 4 by an electromagnetic chuck (not shown) at the inner end of the handle. The structure is such that an article to be processed, such as a semiconductor wafer, can be loaded into each chamber 1.2 or 8 from the conveyance path, or taken out from each chamber into the conveyance space.

A transport case 18 made of a non-magnetic material that can hold the article 17 to be transported and move in the length direction within the transport path 4 as a transport device for transporting the article to be processed into the transport path 4, and this transport case. A floating support guide device using a pair of rails 19 and 19 extending parallel to each other and spaced apart from each other and extending along the conveying pipe 5 so as to levitate and support the 1B in the conveying passage 4 and guide it in the length direction of the conveying passage. and a drive device 20 that drives the transport case 18 with a linear motor.

The transport case 18 has a T-shaped cross section and is made of a non-magnetic material, in particular,
The non-magnetic gold plate is preferably formed of a material, and a plurality of articles 17 such as wafers to be transported are placed on its flat upper surface 18a.
is sandwiched between the holding frames 21 so that it can be held in a row,
Permanent magnets z2.22 are provided longitudinally extending along the bottom and both sides for levitation support and alignment purposes, and a T-shaped cross section as a secondary element cooperating with the primary coil of the linear motor. The vertical legs of the transport case 18 are made of non-magnetic gold (Mu) material, and a conductor plate 23 is provided thereon.

A pair of rails A/19, 19 for supporting and guiding the above-mentioned transport case 18 are formed by permanent magnets, and extend upward from the horizontal portions 19a and 19a for floating support and the outer ends of these horizontal portions. Vertical portions 19b, 19 for alignment
b, and the horizontal part 1 for floating support of the rail 19.19.
ga,: Vertical portions 19b, 19b for alignment with the top surface of tga
Permanent magnets 2 of the transport case 18 facing the sides of the
2. Appropriately select the polarity on the bottom and side surfaces of 22 to avoid magnetic repulsion between the opposing surfaces, so that the bottom surface of the transport case 18 is separated from the top surface of the rail 19.19.
When floating, the center line of the transport case 18 and the rail 1 are aligned.
The structure is such that the center lines between 9 and 19 are maintained in alignment.

The linear motor drive device 20 is composed of a plurality of coils 24 that constitute the primary side of the linear motor, and a vertical leg or conductor plate 28 of the conveyance case 18 that constitutes the secondary side. Placed only in the zone. In the illustrated example, the coils 24 are arranged on both sides of the conductor plate 28 to form a so-called flat shape, but they can also be arranged in a single-sided flat shape.

As described above, in order to arrange the coil 24 group only in the departure zone, in the example shown in the drawings, the recess 25 is formed in the conveyance tube 5 in the departure zone to provide the fill attachment space 26 outside the conveyance tube 5, The group of coils 24 is fixed and removed on a support plate 27 that can be attached or removed by a hinge device or other suitable means in the recessed portion 25, and the group of coils 24 is fixed to a predetermined position in the coil mounting space 26 by the support plate 27. It is located in

Next, the operation of the apparatus configured as described above will be explained.

First, assuming that the transport case 18 is stopped at the starting zone in the transport path indicated by A in FIG. 5 as shown in FIGS. 2 and 3, in this stopped state, the transport case 1
8 is a permanent magnet 22 holding a plurality of wafers 17;
Due to the magnetic repulsion between the rails 22 and the rails IL/19 and 19, the lower surface of the transport case 18 is supported at a floating position slightly upwardly spaced from the upper surfaces of the horizontal portions 19a and 19a of the rails 19 and 19.

Now, of the primary coil 24 group of the drive linear motor provided in the departure zone A portion (in FIG. 8), starting from the rightmost coil /I/24, the left coils are sequentially energized. A magnetic field is generated that moves to the left. An eddy current is induced in the conductor plate 28 of the transport case 18, and this causes an accelerating force to act on the transport case 18, causing it to start moving to the left.

After a predetermined acceleration force is applied, even if no driving force is applied from the outside, there is no running resistance in the transport case other than eddy current loss that occurs on the secondary side, and this loss is relatively and quantitatively Therefore, in practice, after acceleration, the primary coil 24 group of the driving linear motor continuously moves through the constant speed running zone B, which is not provided, at a substantially constant speed V after acceleration. Move to.

In this way, when the next processing station is approached and the deceleration zone O is reached, the primary coils 24 are energized in the opposite phase, and the conveying case 18 is decelerated by increasing the braking force.

The condition for this reverse phase activation is an energy equal to the electromagnetic energy given during acceleration in the starting zone A (more precisely,
As mentioned above, it is set in advance and controlled so that the amount after subtracting the running loss is input.

When it is necessary to stop at a fixed point extremely accurately, it is possible to detect changes in magnetic resistance in the magnetic path or use optical methods to detect the position and speed of the transport case, and feed back the signals for further processing. It is possible to control the pressure and improve accuracy, but in general, under the conditions illustrated here, the load is constant and the running resistance does not change, so the load conditions necessary for stopping should be set in advance. is possible and if necessary,
A magnetic adsorption device can also be installed at a fixed point to ensure fixed point stopping.

The above-mentioned transportation operation from the departure zone A to the multi-travel zone B and deceleration zone C is repeated, for example, multiple processes such as generation, inspection, impurity addition (diffusion, ion implantation, etc.), microfabrication (lithography, etching, etc.) The transport case can be transported between stations corresponding to each of the processing chambers sequentially or repeatedly as required.

Since the inside of the conveyance passage is maintained at a high vacuum, the conveyance tube 5, the rails 19 and 19 installed inside it, and the conveyance case 18 must be subjected to a baking process for degassing. It is preferable to use a heat-resistant magnetic material such as alnico for the magnet.

In addition, r1' required for linear motor drive In the above embodiment, an AC linear motor drive system with a simple structure has been explained, but from control and other requirements, other known linear motors may be used as required. Of course, the drive device can be configured depending on the drive method.

(Effects of the Invention) The greatest advantage of the conveying device according to the present invention is that when conveying articles manufactured in a high vacuum atmosphere, there is no risk of malfunction due to burning of the rotating parts or contamination of the atmosphere. The point is that we were able to eliminate the operation caused by friction and sliding, which is often feared.
Furthermore, according to the present invention, the primary coil of the linear motor is moved along the conveyance path.

By configuring it to be installed only in the acceleration and deceleration zones of stations located a distance apart from each other, there is no installation conflict with branch pipes or gate valves in the middle of the conveyor pipe, and the structure of the equipment can be simplified. be. In addition, as an advantage of the above-mentioned configuration, the linear motor primary coil can be installed in the atmosphere outside the conveyance path, thereby eliminating problems caused by baking treatment and making adjustments and repairs easier. You can also get the effect of being able to.

[Brief explanation of drawings]

FIG. 1 is a schematic perspective view of a high vacuum device equipped with an article conveying device according to the present invention; FIG. 2 is a sectional view of the article conveying device at a station portion where a linear motor primary coil is installed; FIG. 8 is a cross-sectional view taken along the line ■-■ in Figure 2, and shows a side view of the linear motor primary coil dimension space. FIG. 5 is a sectional view similar to the one shown in the figure, and is an explanatory diagram of the operation of the device. 4... Conveyance path 5... Conveyance pipe 17... Article 18... Conveyance case 19... Rail 20 which is a floating support guide device... Drive device 21.
...Holding frame 22...Permanent magnet 28...Conductor plate 24
... Linear motor primary side fill 25 ... recessed part 26 ... coil take-up space 27 ...
・Support plate. Figure 5

Claims (1)

[Scope of Claims] L: A conveyance pipe having a conveyance passage maintained in a high vacuum inside, a conveyance case made of a non-magnetic material that holds an article to be conveyed and is moved into the conveyance passage, and this conveyance case. a floating support guide device that can be floated and supported in a conveyance path and guided along a trajectory; and a linear motor that applies a driving force to the conveyance case, and the floating support guide device extends along the conveyance path. The primary side of the linear motor is composed of a permanent magnet orbit provided in the conveyance path, and a levitation support and alignment permanent magnet provided in the conveyance case so as to act magnetically repulsively with the permanent magnet of this orbit. 1. An article conveyance device in a high vacuum, characterized in that the apparatus is provided only in a starting zone and a deceleration zone of a plurality of stations spaced apart along a conveyance path. 2. The device according to claim 1, wherein the coil on the primary side of the linear motor is provided in the atmosphere outside the conveyance path.