JPH04338028A - In-vacuum carrying machine - Google Patents

Abstract

PURPOSE:To improve the yield or product by preventing generation of dust. CONSTITUTION:A vacuum carrying passage 1 is defined into an upper vacuum chamber A and a lower vacuum chamber B by a partitioning wall 2, and a float table 3 is housed in the upper vacuum chamber A, and a truck 10 to be moved by a linear motor is housed in the lower vacuum chamber B, and floating coils 15a, 15b for magnetically floating the float table 3 with the induction reaction force are arranged in four corners of the top surface of the truck 10.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum conveyor used, for example, in semiconductor manufacturing processes where dust generation is a concern.

0002

BACKGROUND OF THE INVENTION Conventional vacuum conveying machines have used a combination of rolling bearings and linear motors.

0003

[Problems to be Solved by the Invention] In the above-mentioned conventional conveying machine, abrasion powder is generated from the rolling bearings, and as a result, there is a problem that the yield of the product is poor.

SUMMARY OF THE INVENTION An object of the present invention is to provide a vacuum transfer machine that eliminates dust generation and improves product yield.

[0005]

[Means for Solving the Problems] A vacuum conveyor according to the present invention has an upper vacuum chamber and a lower vacuum chamber defined by a partition wall made of non-magnetic, non-conductive material inside a vacuum conveyance path, and A floating table made of conductive material is housed in the chamber, a trolley moved by a linear motor is housed in the lower vacuum chamber, and the floating table is moved to the partition wall without contact with the four corners of the upper surface of the trolley by repulsive force generated by electromagnetic induction. Four levitation coils are respectively arranged to control the attitude and levitation height of the levitation table by independently changing the excitation current or excitation frequency.

Preferably, the primary coil of the linear motor is provided on the bottom surface of the truck, and the secondary conductor is provided on the bottom surface of the lower vacuum chamber.

[0007] Furthermore, the supply of excitation current to the linear motor primary coil and levitation coil on the trolley is carried out by a rail-shaped conductor laid on the bottom of the lower vacuum chamber and a power receiving contact arranged on the trolley. is preferred.

[0008]

[Operation] In the vacuum transfer machine constructed as described above, the carriage is moved by the action of the linear motor.

Furthermore, when an excitation current is supplied to the levitation coil, the conductive levitation table is magnetically levitated by the induced repulsive force caused by electromagnetic induction of the levitation coil, and a gap is formed between the levitation table and the partition wall. As the cart moves, the floating table moves to transport the loaded products. Therefore, a clean atmosphere is maintained in the upper transfer chamber, and the yield of products is improved.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described below with reference to the drawings.

In FIGS. 1 to 3, a vacuum conveying path 1 having a rectangular cross section and kept in a vacuum state by means not shown has a partition wall 2 made of a non-magnetic and non-conductive material parallel to the bottom surface.
It is defined into an upper vacuum chamber A and a lower vacuum chamber B. In the upper vacuum chamber A, a floating table 3 made of a conductive flat plate is housed, and in the lower vacuum chamber B, the entire body is designated by reference numeral 1.
Contains a trolley indicated by 0.

A linear motor is formed on the bottom of the lower vacuum chamber B together with a primary coil 12 of the cart 10, which will be described later. A secondary conductor 4, an on-rail conductor 5 for feeding power to the primary coil, and an on-rail conductor 6 for feeding power to the floating coil, which will be described later, are laid.

Two pairs of running wheels 11 are provided on both sides of the cart 10, and one pair of running wheels 11 is provided on the lower surface of the truck 10 facing the secondary conductor 4.
A secondary coil 12 is provided. Further, levitation coils 15a to 15d are provided at four corners of the upper surface of the truck 10, respectively, with gaps provided in the partition wall 2. The primary coil 12 is connected to a contact 14 that slides on the rail-shaped conductor 5 via an electric wire 13, and the levitation coils 15a to 15d are connected to a contact 17 that slides on the rail-shaped conductor 6 via electric wires 16a to 16d. each connected.

With this structure, when an excitation current is supplied from the rail-shaped conductor 5 to the primary coil 12 via the contact 14 and the electric wire 13, the bogie 1 is moved by a known linear motor action.
0 runs and moves. Also, from the rail-shaped conductor 6 to the contact 17
and levitation coils 13a to 13a through electric wires 16a to 16d.
When an excitation current is supplied to 13d, as shown in FIG. 4, the conductive levitation table 3 moves to its center (coordinates x=0, y= 0) is magnetically levitated such that it coincides with the center of arrangement of the levitation coils 15a to 15d (coordinates X=0, Y=0), and a gap is formed between the levitation coils 15a and 15d. Then, as the cart 10 moves, the floating table 3 moves and transports the loaded semiconductor products (not shown). Therefore, the inside of the upper vacuum chamber A is maintained in a clean atmosphere, and the yield of products is improved. At this time, as shown in FIG. 5, the center of the levitation table 3 (coordinates x=0, y=0)
15d, the induced repulsion force f1 of the levitation coils 15a to 15d is
, f2 are f1=f2. On the other hand, as shown in FIG. 6, the center of the levitation table 3
When the coils 15a to 15d are displaced by a distance Δy from the center of arrangement (coordinates A restoring force acts in the direction (=0, Y=0). In addition, when the attitude or flying height of the levitation table 3 changes, the excitation current to each levitation coil 15a to 15d is changed independently, and the induced repulsion forces f1 to f4 are controlled to change the attitude and flying height. Return to normal value.

[0015]

[Effects of the Invention] Since the present invention is constructed as described above, it is possible to eliminate dust generation from bearings, etc., and improve the yield of products.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view perpendicular to the moving direction showing an embodiment of the present invention.

FIG. 2 is a sectional view taken along line a-a in FIG. 1;

FIG. 3 is a sectional view taken along line bb in FIG. 2;

FIG. 4 is a plan view illustrating electromagnetic repulsion.

FIG. 5 is a sectional view taken along line c-c in FIG. 4;

FIG. 6 is a diagram corresponding to FIG. 5 illustrating restoring force due to induced repulsive force.

[Explanation of symbols]

A... Upper vacuum chamber B...Lower vacuum chamber f1~f4... Induced repulsion force 1...Vacuum conveyance path 2... Bulkhead 3...Levitation table 4... Secondary conductor 5, 6...Rail-shaped conductor 10... Trolley 11... Running wheels 12...Primary coil 13, 16a-16d...Electric wire 14, 17... Contact 15a-15d...levitation coil

Claims (1)

[Claims] 1. An upper vacuum chamber and a lower vacuum chamber are defined by a partition wall made of a non-magnetic, non-conductive material inside a vacuum conveyance path, a floating table made of a conductive material is housed in the upper vacuum chamber, and a floating table made of a conductive material is housed in the upper vacuum chamber; A trolley moved by a linear motor is housed in a vacuum chamber, and the floating table is magnetically levitated via the bulkhead in a non-contact manner by the repulsive force generated by electromagnetic induction at the four corners of the upper surface of the trolley, and an excitation current or excitation frequency is applied. An in-vacuum transfer machine characterized in that four levitation coils are respectively arranged to independently change the attitude and levitation height of the levitation table.