JPH081475A - Turntable equipment - Google Patents

Abstract

(57) [Summary] [Purpose] To obtain a device in which the clean space is not polluted by abrasion powder or the like generated in the bearing portion. [Structure] A partition plate 15 which constitutes a sealing device 14 is provided with the lower surfaces of the permanent magnets 2 and 2 fixed to the turntable body 1 and the upper surfaces of the superconductors 8 and 8 fixed to the fixed housing 3.
To face each other. By circulating liquid nitrogen in the cooling jacket 11, the superconductors 8 are cooled. The rotor 23 is provided at the center of the lower surface of the turntable body 1 and the stator 25 is provided at the center of the upper surface of the fixed housing 3, thereby forming a motor 26.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION A turntable device according to the present invention is incorporated in a semiconductor manufacturing apparatus or a liquid crystal manufacturing apparatus to support a workpiece such as a semiconductor wafer.

[0002]

2. Description of the Related Art A semiconductor manufacturing apparatus, for example, incorporates a turntable for rotating a semiconductor wafer as a workpiece. Moreover, the inside of the semiconductor manufacturing apparatus must be highly vacuum and highly clean. Therefore, conventionally, as a bearing for rotatably supporting the turntable,
Vacuum ball bearings have been used that use solid lubricants such as gold and silver.

[0003]

However, although it is for a vacuum, when a turntable is supported by a ball bearing, a small amount of lubricant or abrasion powder is scattered around, which can reduce the cleanliness of the surroundings. There was a nature. In recent years, more highly integrated semiconductors have been manufactured. Therefore,
It is not preferable that the cleanliness inside the semiconductor manufacturing apparatus is slightly reduced. The turntable device of the present invention was invented in view of such circumstances.

[0004]

SUMMARY OF THE INVENTION A turntable device of the present invention comprises a rotatable turntable body and an annular ring fixed to the lower surface of the turntable body and having the center of rotation of the turntable body as its center. Permanent magnet of
A fixed housing provided below the turntable body, a superconductor supported by the fixed housing and having its upper surface opposed to the lower surface of the permanent magnet with a gap therebetween, and the fixed housing for cooling the superconductor. A sealing device configured to include a cooling device attached to the housing and a partition plate disposed in the gap portion, which shuts off the superconductor and the fixed housing from the outside, and a vacuum device for evacuating the inside of the sealing device. A vacuum means, a rotor fixed to the lower surface of the turntable body above the partition plate, a stator fixed to the fixed housing below the partition plate, and a stator constituting an electric motor in combination with the rotor; Is equipped with.

[0005]

When the turntable device of the present invention constructed as described above is used, the superconductor is cooled by the cooling device,
This superconductor is put into a superconducting state. In this state, the distance between the superconductor supported by the fixed housing and the permanent magnet fixed on the lower surface of the turntable body is kept constant by the pinning effect of the superconductor. As a result, the turntable body remains floating from the fixed housing, and the turntable body can be rotated with a light force. If the stator provided in the fixed housing is energized in this state, the turntable body rotates.

When the turntable device is used, the inside of the closed device is evacuated by the vacuum means. In this state,
The heat conduction from the fixed housing and the superconductor housed in this sealing device to this sealing device is very small. Therefore, even if the temperature of the fixed housing and the superconductor is low,
The temperature of the sealing device never drops. As a result, the temperature of the turntable body facing the partition plate constituting the sealing device will not be lowered more than necessary, and the workpiece placed on the turntable body can be processed under desired temperature conditions. .

[0007]

1 to 3 show an embodiment of the present invention. On the lower surface of the disc-shaped turntable body 1, a plurality (two in the illustrated example) of permanent magnets 2, 2 each formed in an annular shape are arranged concentrically as shown in FIGS. It is arranged. The centers of the permanent magnets 2 and 2 are aligned with the center of rotation of the turntable body 1, that is, the center of the turntable body 1. Also, each of these permanent magnets 2,
2 is magnetized in the axial direction (vertical direction in FIG. 1). Further, the upper end of the guide cylinder 6 is externally fitted and fixed to the outer peripheral edge of the turntable body 1. Therefore, this guide tube 6
The lower half part is in a state of being hung from the lower surface of the turntable body 1.

On the other hand, a fixed housing 3 is provided below the turntable body 1. The fixed housing 3 has a housing body 4 formed in a thick disk shape and a bottom plate 5 formed in a disk shape having a diameter slightly larger than the housing body 4 and abutted against the lower surface of the housing body 4. It consists of and. Of the housing body 4 and the bottom plate 5, at least the housing body 4 is made of a metal having good heat conductivity such as copper or aluminum. It should be noted that both members 4 and 5 are preferably made of materials having similar thermal expansion coefficients (more preferably the same material).
The contact surface between the lower surface of the housing body 4 and the upper surface of the bottom plate 5 is sealed with an adhesive, a brazing material or the like.

As shown in FIGS. 1 and 3, a plurality of recesses 7 and 7 are formed in the outer peripheral portion of the upper surface of the housing body 4, and the superconductors 8 and 8 are provided in the recesses 7 and 7, respectively. Are fitted and fixed. The recesses 7, 7 are arranged on an arc centered on the centers of the turntable body 1 and the housing body 4. Therefore, the upper surfaces of the superconductors 8 and 8 fixed in the recesses 7 and 7 face the lower surfaces of the permanent magnets 2 and 2 with gaps 9 and 9 therebetween.

As the above-mentioned superconductors 8, various conventionally known ones can be used. However, the yttrium (Y) type superconductor is in a superconducting state at the temperature of liquid nitrogen, and the operating cost is low. It is preferable because it can be done. Further, among these, the one containing a normal conducting phase in the superconducting phase can be preferably used since a large pinning force can be obtained and the turntable body 1 having a heavy weight can be levitated.

An annular recess 10 is formed in a portion of the housing body 4 near the outer periphery of the lower surface, and a space surrounded by the recess and the upper surface of the bottom plate 5 serves as a cooling jacket 11. Then, the upper end of the coolant feed pipe 12 is connected to one end side (left side in FIG. 1) of the cooling jacket 11, and the upper end part of the coolant take-out pipe 13 is connected to the other end side (right side in FIG. 1). The cooling device 27 is configured.

The fixed housing 3 and the superconductors 8, 8 are shielded from the outside by a sealing device 14. The sealing device 14 includes a partition plate 15 arranged in the gap 9 portion, an outer cylinder 16 arranged around the fixed housing 3, and a lower plate 17 provided below the fixed housing 3. It consists of and. Partition plate 15
Is made of a non-magnetic material such as copper, aluminum, or synthetic resin, and is formed into a thin disk shape. The outer diameter of the upper half of the outer cylinder 16 is smaller than the inner diameter of the guide cylinder 6,
A holding portion 19 having a crank-shaped cross section is formed at the lower end of the outer cylinder 16.

A portion of the outer peripheral end portion 5a of the bottom plate 5 of the fixed housing 3 which protrudes from the outer peripheral surface of the housing body 4 enters the inside of the holding portion 19. And
With the heat insulating materials 18a and 18b sandwiched between the upper surface of the outer peripheral end 5a and the lower surface of the holding portion 19 and between the lower surface of the outer peripheral end 5a and the upper surface of the lower plate 17, the holding is performed. The portion 19 is screwed and fixed to the lower plate 17.
The contact portion between the outer peripheral edge portion of the partition plate 15 and the upper end edge portion of the outer cylinder 16 and the contact portion between the lower surface of the outer cylinder 16 and the upper surface of the lower plate 17 are adhesive and brazing material, respectively. It is sealed with etc. Further, between the upper surface of the housing body 4 and the superconductors 8, 8 and the lower surface of the partition plate 15, between the outer peripheral surface of the housing body 4 and the inner peripheral surface of the outer cylinder 16, and the outer surface of the bottom plate 5. A gap is provided between the peripheral edge and the inner peripheral surface of the holding portion 19. Therefore, the fixed housing 3
The superconductors 8 and 8 are held in the sealing device 14 in a state where they do not come into contact with other members except for the coolant feed pipe 12, the coolant discharge pipe 13, and the heat insulating materials 18a and 18b.

Further, the coolant feed pipe 12 and the coolant take-out pipe 13 are provided with through holes 20 formed in the lower plate 17.
It is inserted through a and 20b and protrudes below the lower plate 17. Then, bellows 21a and 21b are provided between the outer peripheral surfaces of the lower ends of the tubes 12 and 13 and the lower end openings of the through holes 20a and 20b to maintain airtightness inside and outside the sealing device 14. Further, a vacuum means is provided on the upper surface of the central portion of the lower plate 17 to open the end portion of the exhaust pipe 22 leading to a negative pressure source such as a vacuum pump (not shown) so as to evacuate the inside of the sealing device 14. are doing.

Further, a rotor 23 is fixed to the center of the lower surface of the turntable body 1 above the partition plate 15 concentrically with the permanent magnets 2 and 2. Also, the partition plate 1
A circular recess 24 is formed in the central portion of the upper surface of the housing body 4, which is located below 5, and the stator 25 is fixed in the recess 24. The rotor 23 and the stator 25 have a thrust ring-shaped stepping motor 26.
The turntable body 1 is rotationally driven by a predetermined angle based on the energization.

When the turntable device of the present invention constructed as described above is used, the liquid nitrogen fed from the coolant feeding pipe 12 is taken out from the coolant taking-out pipe 13 so that the liquid is introduced into the cooling jacket 11. Circulate nitrogen. As a result, the housing body 4 and the superconductors 8 and 8 are cooled to the temperature of liquid nitrogen (77 ° K), and the superconductors 8 and 8 are brought into a superconducting state. At the same time, the air in the sealing device 14 is exhausted through the exhaust pipe 22 to create a vacuum inside the sealing device 14. still,
The semiconductor manufacturing apparatus incorporating the turntable device of the present invention keeps the inside in a high vacuum and a high clean state at the time of use. Therefore, in the use state, the space around the sealing device 14 is also evacuated. Therefore, a large pressure difference does not occur between the upper and lower sides of the partition plate 15 during use, and the partition plate 15
Does not bend significantly. In the preparatory stage before the start of use, the inside of the sealing device 14 may be vacuum and the surroundings may be atmospheric pressure, but in this case as well, the lower surface of the partition plate 15 is supported by the upper surface of the housing body 3. Therefore, the partition plate 15 does not bend excessively and break.

As described above, the superconductors 8 and 8 are brought into a superconducting state, and the turntable body 1 is slightly lowered (pushed down). At this time, a spacer is sandwiched between the inner peripheral surface of the guide cylinder 6 and the upper outer peripheral surface of the outer cylinder 16 so that the distance between these peripheral surfaces is kept uniform over the entire circumference. Like Therefore, regardless of the lowering of the turntable body 1, the turntable body 1 and the fixed housing 3 are held concentrically with each other. When the turntable body 1 having the permanent magnets 2 and 2 fixed thereto is pushed down toward the superconductors 8 and 8 in the superconducting state as described above, the so-called pinning effect that the superconductors 8 and 8 hold the magnetic flux The distance between the superconductors 8 and 8 supported by the fixed housing 3 and the permanent magnets 2 and 2 fixed to the lower surface of the turntable body 1 is kept constant. The spacer is removed after lowering the turntable body 1.

As a result, the turntable body 1 is kept floating from the fixed housing 3, and the turntable body 1 can be rotated with a light force. When the stator 25 provided in the fixed housing 3 is energized in this state, the turntable body 1 rotates. In the illustrated embodiment, the stator 25 and the rotor 23 form a thrust ring-shaped stepping motor 26, so that the turntable body 1 can be accurately rotated by a predetermined angle. Therefore, the work of indexing the workpiece can be performed easily and accurately.

Further, when the turntable device is used, the air inside the sealing device 14 is evacuated by exhausting the air inside the sealing device 14 through the exhaust pipe 22. In this state, the heat transfer from the fixed housing 3 and the superconductors 8, 8 housed in the sealing device 14 to the sealing device 14 causes the coolant feeding pipe 12 and the coolant taking-out pipe 1 to flow.
3. Only a very small amount is transmitted through the heat insulating materials 18a and 18b. Therefore, even if the temperature of the fixed housing 3 and the superconductors 8 is lowered, the temperature of the sealing device 14 does not decrease. As a result, the temperature of the turntable body 1 facing the partition plate 15 constituting the sealing device 14 does not drop more than necessary, and the workpiece placed on the turntable body 1 is heated to a desired temperature. Can be processed under the conditions.

Further, since the temperature rise of the fixed housing 3 is suppressed, the evaporation of the liquid nitrogen flowing in the cooling jacket 11 can be suppressed. Therefore, the replenishment of liquid nitrogen is small and the operating cost of the turntable device can be suppressed.

[0021]

Since the turntable device of the present invention is constructed and operates as described above, no foreign matter such as lubricant or abrasion powder is generated during operation. Therefore, even if it is installed in an ultra-highly clean space, the cleanliness in this space is not reduced, and it is possible to manufacture semiconductors and the like having high quality and high reliability.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of the present invention.

FIG. 2 is a bottom view of the turntable body.

FIG. 3 is a plan view of a fixed housing.

[Explanation of symbols]

 1 Turntable Main Body 2 Permanent Magnet 3 Fixed Housing 4 Housing Main Body 5 Bottom Plate 5a Outer Edge 6 Guide Tube 7 Recess 8 Superconductor 9 Gap 10 Recess 11 Cooling Jacket 12 Coolant Feeding Pipe 13 Coolant Extracting Pipe 14 Sealing Device 15 Partition Plate 16 Outer Cylinder 17 Lower Plate 18a, 18b Heat Insulating Material 19 Holding Parts 20a, 20b Through Holes 21a, 21b Bellows 22 Exhaust Pipe 23 Rotor 24 Recess 25 Stator 26 Stepping Motor 27 Cooling Device

Claims (1)

[Claims] 1. A rotatable turntable main body, an annular permanent magnet fixed to the lower surface of the turntable main body with the center of rotation of the turntable main body as its center, and below the turntable main body. A fixed housing provided, a superconductor supported by the fixed housing, the upper surface of which faces the lower surface of the permanent magnet via a gap, and a cooling device attached to the fixed housing for cooling the superconductor. A sealing device configured to include a partition plate disposed in the gap portion to shut off the superconductor and the fixed housing from the outside, a vacuum means for making the inside of the sealing device a vacuum, and the partition plate. The rotor fixed to the lower surface of the turntable body on the upper side of, and fixed to the fixed housing on the lower side of the partition plate in combination with the rotor. A turntable device including a stator that constitutes an electric motor.