JPH0297268A - Magnetic levitation carrier arm - Google Patents

Abstract

PURPOSE:To make the occupied space within a vacuum vessel small to miniaturize the vacuum vessel by housing a magnetic body and a driving source 4 moving the magnetic body axially in a vacuum airtight structure cylindrical body provided within the vacuum vessel, by arranging a mover at the outer periphery of the cylindrical body, and by fitting the mover with an arm, on which a body to be conveyed is placed. CONSTITUTION:An annular soft iron 3 and a driving source 4 moving the soft iron axially are provided in a vacuum airtight structure cylindrical body 2 provided within a vacuum vessel 1. A mover 6 by an electromagnet 5 is arranged at the outer periphery of the cylindrical body 2 and the mover 6 is fitted with an arm 8, on which a wafer 7 is placed. The part of the cylindrical body 2, which part is vacuum-sealed by an O-ring 10 to the vacuum vessel 1, is rotatably pivoted by a shank 9 by use of a magnetic fluid seal, etc. When a screw shaft 4c is rotated by a motor 4a in this constitution, the arm 8 moves in a levitated state and the wafer 7 is carried in and out through an entrance and exit 11.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is a method for transporting an object such as a semiconductor wafer into a vacuum container used in a device applying vacuum technology, such as a plasma etching device or a plasma CVD device. It is related to a transfer arm that transports objects to be transported, transported outside a vacuum container, or between vacuum containers, and in particular uses the attraction force of a magnet to magnetically levitate an arm with a transported object to move it. In particular, the present invention relates to a magnetically levitated transport arm for transporting objects.

[Conventional technology and its issues]

FIG. 3 is a plan view showing an example of a conventional transfer arm, and this first conventional example has an extendable articulated arm 12, a drive device 13 for extending and contracting this, and an articulated arm 12 in a vacuum container (not shown). A mounting section 14 is connected to the wafer 7 on which the wafer 7 is mounted, and the articulated arm 12 is extended and contracted by a drive device 13 to carry the wafer 7 into and out of the vacuum container.

However, in the first conventional example, there are many parts installed in the vacuum container, and sliding parts are present at the joints of the arms, so there are problems with lubrication, dust generation, etc.

FIG. 4 is a longitudinal sectional view showing the configuration of a second conventional example devised to solve such problems. In this second conventional example, a case body 15 having a U-shaped cross section is provided inside the vacuum vessel 1. In the annular part of this case body 15, a moving body made of an electromagnet 5, a belt 4f that moves this moving body in the axial direction, and this heald 4f are disposed.
The case body 15 houses a pulley 4d suspending the
A soft iron 3 is placed in the center of the wafer 3, and an arm 8 on which a wafer 7 is mounted is attached to the soft iron 3. Reference numeral 11 denotes an entrance/exit of the arm 8 provided in the vacuum container 1, which is sealed with a door (not shown) after the wafer 7 is carried in.

In such a second conventional example, the motor 4a is driven and the pulley 4
The soft iron 3 attracted by the electromagnet 5 is moved by moving the moving body by the electromagnet 5 by moving the bell) 4f via the bell d, and the wafer 7 is moved into the vacuum container 1 by the movement of the arm 8 attached to the soft iron 3. It is carried in and carried out through the entrance/exit 11 of the building.

In this second conventional example, a movable body including an electromagnet 5 is provided in a case body 5 having a U-shaped cross section and partitioned from the vacuum container 1.
In addition, the movable part (i.e., the soft iron 3 and the arm 8 attached to it and on which the wafer 7 is placed) is levitated by the electromagnet 5, so that there is no sliding part in the vacuum container 1. The case body 15 has a complicated shape, the movable pulley 4d by the electromagnet 5, the belt 4f, and the motor 4a must be incorporated into the case body 15 having a complicated shape. When it is pulled in, the arm part on which the knee huff is placed protrudes from the case body 15, which not only makes the structure complicated and difficult to manufacture but also expensive. Since my body is 15 years old, I have been traveling on business,
The space occupied in the vacuum container 1 becomes large, and the vacuum container 1
There are issues such as the large size of the

Further, the case body 15 is rotatably supported on the vacuum container 1 by a shaft portion 9 sealed by an O-ring 10, and by rotating the shaft portion 9, the wafer 7 can be transported in any direction. In this case, there is also the problem that the space occupied becomes larger.

[Means to solve the problem]

In order to solve the above-mentioned problems, the transport arm of the present invention has the following features:
As shown in the second figure, a cylinder 2 having a vacuum-tight structure is provided in a vacuum container 1, and a magnetic body 3 and a drive source 4 for moving the magnetic body 3 in the axial direction are housed in the cylinder 2. A movable body 6 made of magnets 5 is disposed around the outer periphery, and an arm 8 on which an object 7 to be transported is placed is attached to the movable body 6.

[For production]

When the magnetic body 3 is moved in the axial direction by the drive source 4, the moving body 6 made of the magnet 5 and the arm 8 attached to it move in a floating state as the magnetic body 3 moves. Due to the movement, the conveyed object 7 placed thereon is conveyed.

〔Example〕

The present invention will be described in detail below based on the drawings.

FIG. 1 is a longitudinal cross-sectional view showing the configuration of an embodiment of the transport arm of the present invention, and FIG. 2 is a simplified side view of the vicinity of the moving body in the present invention.

1st. In FIG. 2, 1 is a vacuum container, and 2 is a cylindrical body with a vacuum-tight structure provided within the vacuum container 1. In FIG. Inside this cylindrical body 2, an annular soft iron 3 and a drive source 4 for moving the annular soft iron 3 in the axial direction are provided. The drive source 4 includes a nut 4b fixed to the center of the soft iron 3, a screw shaft 4C screwed into the nut 4b, and a motor 4a that rotates the screw shaft 4C.

A moving body 6 made of an electromagnet 5 is arranged around the outer periphery of the cylindrical body 2, and an arm 8 on which a wafer 7 is mounted is attached to this moving body 6. Cylindrical body 2 is attached to vacuum container 1 with ○ ring 1
0 is rotatably supported by a shaft portion 9 using a magnetic fluid seal or the like. 1
1 is an entrance/exit of an arm 8 provided in the vacuum container 1;
When the wafer 7 is carried in, it is sealed by a door (not shown).

In the above configuration, when the screw shaft 4C is rotated by the motor 4a, the nut 4b screwed thereon and the soft iron 3 move in the axial direction, and as the soft iron 3 moves, the moving body 6 by the electromagnet 5 and the moving body 6 attached thereto are moved. The arm 8 moves in a floating state, and as the arm 8 moves, the wafer 7 placed thereon is transported and carried in and out from the entrance/exit 11 of the vacuum container 1.

Further, when the shaft portion 9 is rotated, the cylindrical body 2. The soft iron 3 and the drive source 4 that moves it rotate, and the rotation of the soft iron 3 causes the moving body 6 and the arm 8 formed by the electromagnet 5 to rotate, so that the wafer 7 placed on the arm 8 can be directed in any direction. , the wafer 7 can be transported in any direction. In this case, the arm portion on which the wafer 7 is placed can rotate from the end face of the cylindrical body 2 with almost no protrusion, so that the vacuum container 1 can be made smaller.

〔Effect of the invention〕

-1- As is clear from the above description, according to the present invention, the cylinder 2 having a vacuum-tight structure can be made into a simple shape, and the magnetic body 3 and the driving source 4 can be easily installed inside the cylinder 2 having a simple shape. The structure is simple, easy to manufacture, and can be implemented at low cost, as the arm part on which the transported object 7 is placed can be almost retracted from the end face of the cylinder 2, and the vacuum container 1 The space occupied within the vacuum vessel 1 can be made smaller than that of the conventional example shown in FIG. 4, and the vacuum vessel 1 can be made smaller.

In addition, since the vacuum container 1 can be made small, it can be quickly evacuated to a high vacuum, and the inside of the cylinder 2, which has a vacuum-tight structure, can be easily evacuated, and there are few moving parts and no sliding parts. Therefore, there is an advantage that there is no risk of dust generation.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view showing the configuration of an embodiment of the conveyance arm of the present invention, FIG. 2 is a simplified side view of the vicinity of the moving body in the present invention, and FIG. 3 is a plan view showing an example of the conventional conveyance arm. Fourth
The figure is a longitudinal sectional view showing the configuration of the other side of a conventional transfer arm. 1... Vacuum container, 2... Vacuum-tight structure cylinder), 3... Magnetic material (soft iron), 4...
...Drive source, 4a...Morph, 4b...
...Nut, 4c...Screw shaft, 5...
・(Electric) magnet, 6... Moving object, 7...
Transferred object (wafer), 8...Arm, 9...
...Shaft part.

Claims (2)

[Claims] (1) A cylindrical body 2 with a vacuum-tight structure is provided in the vacuum container 1,
A magnetic body 3 and a drive source 4 for moving the magnetic body 3 in the axial direction are housed in this cylinder 2, and a moving body 6 formed by a magnet 5 is placed around the outer periphery of the cylinder 2.
A magnetically levitated transfer arm is provided, and an arm 8 on which an object 7 is placed is attached to the movable body 6. (2) A magnetically levitated transfer arm in which a vacuum-tight cylindrical body 2 is rotatably supported by a shaft portion 9 sealed to a vacuum container 1.