JPH0719244A - Magnetic bearing unit - Google Patents

Abstract

PURPOSE:To provide a magnetic bearing unit that is miniaturized and capable of reducing pollution in a chamber. CONSTITUTION:This magnetic bearing unit is provided with two upper and lower thrust electromagnets 69 and 70 being opposed to both upper and lower surfaces of a thrust disk 66 installed at the lower side of a turning shaft 42 in a chamber, and a lower radial electromagnet 77 being opposed to a cover overspreading the layered end of a lower radial layered yoke 78 secured to an outer circumferential part of the thrust disk 66, respectively. Also it is provided with a radial displacement sensor being installed in space between two magnetic poles of this electromagnet and using a cover as a detecting surface, and an upper radial electromagnet 49 being opposed to a cover overspreading the layered end of an upper radial layered yoke 50 secured to an upper side of the turning shaft 42, and another radial displacement sensor being installed in space between two magnetic poles of this electromagnet in addition. Therefore, possible scattering of rust from each layered end of both these lower and upper radial layered yokes 78 and 50 is prevented by the covers, and respective these electromagnets and displacement sensors are all installed in such a setup that they are not lined up in a row in the axial direction of the turning shaft 42.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic bearing device used in, for example, a semiconductor manufacturing apparatus.

[0002]

2. Description of the Related Art Since magnetic bearing devices have the characteristics of non-contact, non-lubrication, and long life, various researches and application developments have been made in various fields. A linear motion type magnetic bearing device has been put to practical use in a magnetic levitation transfer device and a handling device of a semiconductor manufacturing apparatus. However, in an apparatus such as a chemical vapor deposition apparatus (CVD apparatus) that forms a thin film of a predetermined component on a semiconductor substrate that requires a depressurized and clean atmosphere, a bearing device that rotatably supports a rotating body is mainly used. A ball bearing was used for the magnetic bearing device, and the magnetic bearing device was under practical application.

A bearing device in a conventional CVD apparatus will be described below with reference to FIGS. 9 and 10. FIG. 9 is a sectional view showing a schematic configuration of a main part of a ball bearing used for rotation support, and FIG. 10 is a sectional view showing a schematic configuration of a main part of a magnetic bearing used for rotation support.

First, a ball bearing is used as shown in FIG.
Will be described. In the figure, reference numeral 1 is a vertical rotating body provided inside the chamber 2 under reduced pressure. Between the rotating shaft 3 of the rotating body 1 and the lower portion of the chamber 2, the rotating body 1
An upper ball bearing 4 and a lower ball bearing 5 for rotatably supporting the rotating body 1 are provided, and the rotating body 1 is rotationally driven by a drive shaft that penetrates airtightly in an electric motor 6 provided outside the chamber 2. Further, the rotating body 1 is provided with a susceptor 7 which rotates in a horizontal plane on an upper portion thereof, and a semiconductor substrate on which a thin film is formed is placed on the susceptor 7.

While the thin film is being formed on the semiconductor substrate, the rotating body 1 on which the semiconductor substrate is placed rotates, and the inner rings of both ball bearings 4 and 5 also rotate at the same time. Therefore, the lubricating oil of both ball bearings 4 and 5 may diffuse into the chamber 2 to contaminate the thin film formed on the semiconductor substrate and reduce the product yield.

Further, if rust is generated in both ball bearings 4 and 5, the inside of the chamber 2 will be contaminated and the rusted bearing will be galled and the rotor 1 will not rotate.
In such a case, the ball bearing needs to be replaced, but the replacement takes a lot of time.

On the other hand, in consideration of the situation in which the ball bearing is used for the rotation support as described above, the examination using the magnetic bearing device has been made. Next, a device using the magnetic bearing device will be described with reference to FIG. In the figure, 8 is a vertical rotating body housed in the chamber 9 under reduced pressure. The rotating body 8 is provided with a susceptor 10 on which a semiconductor substrate for forming a thin film is placed and which rotates in a horizontal plane, and a rotating shaft 11 on the lower portion. A vacuum shield 12 is provided close to the rotating shaft 11.

The rotary body 8 has radial magnetic bearings 13 and 14 provided on the upper and lower portions of its rotary shaft 11 and a thrust magnetic bearing 16 provided between the bearings 13 and 14.
It is levitationally supported by and is rotationally driven by the electric motor 15. The radial magnetic bearings 13 and 14 are laminated yokes 17 and 18 axially laminated on the rotary shaft 11, and upper and lower electromagnets 19 and lower electromagnets fixed to the chamber 9 facing them via a vacuum shield 12. The thrust magnetic bearing 16 is also provided with an electromagnet 21 fixed to the chamber 9.

Further, displacement sensors 22 and 23 are attached to the chamber 9 along the axial direction of the rotary shaft 11 so as to face the rotary shaft 11 via the vacuum shield 12, and the displacement sensors 22 and 23 are mounted on the rotary shaft 11. The axial and radial displacements of the rotating body 8 are detected by the radial magnetic bearing 13,
14 and the thrust magnetic bearing 15 are controlled. 24
Is a stator of the electric motor 16 which is also fixed to the chamber 9.

In the structure thus configured, each magnet 1
Since 9, 20, 21 and the displacement sensors 22, 23 and the stator 24 are arranged in a direction parallel to the rotation axis direction, the magnetic bearing device becomes long in the same axis direction. In addition, the vacuum shield 12 is interposed and the rotating body 8
Since they are supported in a non-contact manner, the magnetic air gap of the electromagnet becomes large, which inevitably increases the force required for support, resulting in a large apparatus.

Further, since the laminated end faces of the laminated yokes 17 and 18 provided on the rotary shaft 11 are exposed inside the depressurized chamber 9, if the end faces are rusted, the rotor 8 will be damaged. Although rust is scattered with rotation and its end surface becomes a dust source, it does not stop rotating due to rusting like ball bearings and it does not take time to replace bearings, There is a possibility that it may be contaminated and the product yield may be reduced.

[0012]

SUMMARY OF THE INVENTION As described above, conventionally,
With ball bearings, there is a risk that the rusting of the ball bearings exposed inside the housing and the evaporation of lubricating oil may contaminate the inside of the housing, and it will take a lot of time to replace the rusted ball bearings. In addition, in the magnetic bearing device, there is a possibility that the end surface of the laminated yoke exposed in the housing may be rusted to contaminate the inside of the housing, and since the electromagnets and the like are provided side by side in the axial direction through the shield, It was long and large in the axial direction. The present invention has been made in view of such circumstances, and an object of the present invention is to provide a miniaturized magnetic bearing device capable of reducing contamination in the housing.

[0013]

A magnetic bearing device of the present invention comprises a vertical rotating body housed in a housing and provided with a thrust disk on one end side of a rotary shaft, and a gap between the upper and lower surfaces of the thrust disk. Is provided to support the rotating body in the thrust direction in a non-contact manner with the magnetic poles facing each other, and the lower thrust electromagnet and the surface of the thrust disk are provided as detection surfaces to provide signals for controlling the upper and lower thrust electromagnets. A thrust displacement sensor for outputting, a first radial laminated yoke fixed to the outer peripheral portion of the thrust disk and having an outer peripheral laminated end surface covered with a first cover,
A first radial electromagnet for supporting one end of a rotating body in a radial direction in a non-contact manner with magnetic poles facing each other with a gap provided on the outer peripheral laminated end surface of the first radial laminated yoke, and the first radial electromagnet. Between the magnetic poles of the first cover, which is attached to the outer surface of the first cover as a detection surface, outputs a signal for controlling the first radial electromagnet, and a radial displacement sensor fixed to the other end of the rotary shaft. The second radial laminated yoke whose laminated end surface is covered with the second cover and the outer peripheral laminated end surface of the second radial laminated yoke are arranged so that the magnetic poles are opposed to each other and the other end of the rotor is A second radial electromagnet supported in a non-contact manner in the radial direction, and a signal for attaching the outer surface of the second cover as a detection surface between the magnetic poles of the second radial electromagnet and controlling the second radial electromagnet. Other output And a radial displacement sensor on the side, and the thrust displacement sensor is provided between the magnetic poles of one of the upper and lower thrust electromagnets having an annular U-shaped cross section. It is characterized by being.

[0014]

The magnetic bearing device configured as described above is provided with an upper and lower thrust electromagnets facing the upper and lower surfaces of a thrust disk provided on one end side of a rotating shaft of a rotating body housed in a housing, and a thrust thrust magnet. The first opposing first cover that covers the laminated end face of the first radial laminated yoke fixed to the outer peripheral portion of the disc
Of the radial electromagnet, the radial displacement sensor on one end side which is attached between the magnetic poles of the first radial electromagnet and has the outer surface of the first cover as a detection surface, and the second radial displacement sensor fixed on the other end side of the rotary shaft. A second radial electromagnet that faces the second cover that covers the laminated end surface of the radial laminated yoke, and the other end side that is attached between the magnetic poles of the second radial electromagnet and that has the outer surface of the second cover as the detection surface. Since the first radial laminated yoke or the second radial laminated yoke may have rust on the laminated end face of the first radial laminated yoke or the second radial laminated yoke, the first cover or the second radial laminated sensor The cover prevents the scattering of rust. Further, the upper and lower thrust electromagnets and the first radial electromagnet are not arranged in the axial direction of the rotating shaft, and the radial displacement sensor on one end side and the radial displacement sensor on the other end side both have the first displacement. The radial electromagnet and the second radial electromagnet are arranged at the same position in the axial direction of the rotating shaft. For this reason, contamination in the housing can be reduced, and the magnetic bearing device can be downsized.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 is a vertical cross-sectional view of a main part of a CVD apparatus, FIG. 2 is a cross-sectional view showing the outline of the overall configuration of the CVD apparatus, FIG. 3 is a vertical cross-sectional view of the main part of an electric motor, and FIG. FIG. 5 is a vertical cross-sectional view of an upper radial laminated yoke portion of the radial magnetic bearing portion, FIG. 5 is a vertical cross-sectional view of a lower radial laminated yoke portion of the lower radial magnetic bearing portion, and FIG. 6 is a cross section of the upper radial magnetic bearing portion. FIG. 7 is a plan view, FIG. 7 is a cross-sectional view of the lower radial magnetic bearing portion, FIG. 8 is a view for explaining detection of displacement by a displacement sensor, and FIG. 8A is a displacement detected by the radial displacement sensor. FIG. 8B is a diagram illustrating the displacement detected by the radial displacement sensor and the thrust displacement sensor.

In FIGS. 1 to 7, reference numeral 31 is a CVD apparatus, and a chamber 32 for accommodating its semiconductor substrate and performing vapor phase growth of a predetermined thin film is provided with an upper case 34 on a top surface of a base 33 in an airtight manner. Configured to wear. An exhaust pipe 35 is provided in the base 33 so that an end portion is opened inside the chamber 32, and a vacuum state or the like inside the chamber 32 is maintained by a vacuum pump or the like connected to the exhaust pipe 35. Further, a gas supply pipe 36 is also provided in the upper case 34 so that an end portion is opened inside the chamber 32, and a predetermined source gas is supplied from the gas supply source (not shown) into the chamber 32. It
The exhaust pipe 35 described above also switches the port to collect the raw material gas.

Further, inside the chamber 32, a susceptor 37 for mounting a semiconductor substrate on the upper surface is arranged below the gas supply pipe 36, and the susceptor 37 is attached to the base 33 so as to penetrate therethrough. It is provided on the upper part of the rotating body 38 of the mold. Then, the susceptor 37 rotates so that a uniform thin film is formed on the semiconductor substrate during the vapor phase growth.

On the other hand, the rotating body 38 has a substantially cylindrical shape.
It is supported in a non-contact manner by the magnetic bearing device 40 attached to the lower surface of the base 33. The magnetic bearing device 40 includes an upper radial bearing portion 43 and a lower radial bearing portion 44, which are provided along the axial direction of the rotating shaft 42 of the rotating body 38, in a bearing case 41 hermetically attached to the lower surface of the base 33.
And a thrust bearing portion 45 integrally provided with the lower radial bearing portion 44, and at the same time, an electric motor 46 for rotationally driving the rotating body 38 is provided in the bearing case 41.
It is provided between the upper radial bearing portion 43, the lower radial bearing portion 44, and the thrust bearing portion 45.

Inside the rotating body 38, a lower portion is airtightly attached to a bearing case 41, a heater supporting member 47 is axially penetrated, and a heater unit 48 above the heater supporting member 47 is provided. Susceptor 37
The heater unit 48 heats the semiconductor substrate mounted on the upper surface of the susceptor 37. The temperature of the heater unit 48 is adjusted by a controller (not shown).

Further, the upper radial bearing portion 43 of the magnetic bearing device 40 has a substantially annular upper radial electromagnet 49 fixed to the inner surface of the bearing case 41, and the rotary shaft 42 so that the outer surface of the lamination faces the inner diameter surface of the upper radial electromagnet 49. And an upper radial laminated yoke 50 press-fitted to the outer surface of the. The upper radial laminated yoke 50 is formed by laminating annular silicon steel plates in the axial direction, and a cover 51 made of a stainless steel plate is provided on the laminated end face thereof so that the laminated end face is not directly exposed to the outside. It is like this.

Further, the upper radial electromagnets 49 project inwardly in pairs from four equally-arranged positions of the substantially annular upper radial magnetic pole ring 52, and the upper radial laminated yoke 50 is formed.
Eight protruding magnetic poles 53a, 53b, 53c, 53 forming a minute gap with the cover 51 provided on the laminated end surface of
d, 53e, 53f, 53g, 53h, and these protruding magnetic poles 53a, 53b, ..., 53h have coils 54a, 54b, 54c, 54d, 54e, 54f, 5 respectively.
4g and 54h are wound.

The pair of projecting magnetic poles 53a,
53b and protruding magnetic poles 53c and 53d adjacent to both sides thereof
The first and second radial displacement sensors 55 and 56 have an angle of 90 degrees in the same plane between the protruding magnetic poles 53g and 53h, and cover the laminated surface of the upper radial laminated yoke 50. A gap is provided between the cover 51 and the upper radial magnetic pole ring 52 so that the outer surface of the cover 51 serves as a displacement detection surface.

The electric motor 46 is provided on the lower side of the upper radial bearing portion 43 of the bearing case 41, and is fixed to the inner surface of the bearing case 41 and has a stator core formed by axially laminating silicon steel plates having a plurality of protrusions inside. A stator 59 in which a plurality of coils 58 are wound around a protrusion 57, and a rotary shaft 42.
Of the upper radial laminated yoke 50 of FIG. And stator core 5
7 is also provided with a cover 61 formed by molding synthetic resin or applying synthetic resin paint so that the laminated end surface is not directly exposed to the outside. Further, the rotor 60 is the upper radial laminated yoke 5 of the rotary shaft 42.
0 is inserted into the intermediate sleeve 62 press-fitted to the lower side of the permanent magnet 6
3 is molded and fixed with a synthetic resin material 64, and a fixed cylinder 65 made of a stainless steel plate is attached to the outer surface as a cover.

Further, the thrust bearing portion 45 provided on the lower side of the electric motor 46 has a thrust disc 66 fixed to the lower portion of the rotary shaft 42, and upper thrust electromagnets 67 on the upper and lower sides of the thrust disc 66. And lower thrust electromagnet 6
And 8 are provided. The upper thrust electromagnet 67 and the lower thrust electromagnet 68 have a substantially U-shaped annular yoke 6 whose cross-sectional shape opens downward and upward, respectively.
Thrust coils 71 and 72 are provided at 9, 70.

The upper thrust electromagnet 67 and the lower thrust electromagnet 68 have two annular magnetic poles 73a and 73, respectively.
b, 74a and 74b face the upper surface and the lower surface of the thrust disc 66 with a minute gap therebetween. Further, a fixed disc 75 is provided on the upper thrust electromagnet 67, and the thrust coil 71 is fixed so as not to fall. The fixed disc 75 has a pair of projecting magnetic poles 53 a of the upper radial electromagnet 49. A thrust displacement sensor 76 is attached at a position corresponding to 53b so that a gap is provided with respect to the upper surface of the thrust disc 66 and the upper surface serves as a displacement detection surface.

Further, the lower radial bearing portion 44 is composed of a substantially annular lower radial electromagnet 77 fixed to the inner surface of the bearing case 41, and the outermost circumference of the thrust disc 66 so that the inner surface of the lower radial electromagnet 77 faces the laminated outer surface. A lower radial laminated yoke 78 press-fitted to the portion is provided. The lower radial laminated yoke 78 is formed by laminating annular silicon steel plates in the axial direction, and a cover 79 made of a stainless steel plate is provided on the laminated end face thereof so that the laminated end face is not directly exposed to the outside. Has become.

Further, the lower radial electromagnets 77 project inwardly in pairs from the four equally-arranged positions of the substantially annular lower radial magnetic pole ring 80, and the lower radial laminated yoke 78.
Eight protruding magnetic poles 81a, 81b, 81c, 81 forming a minute gap with the cover 79 provided on the laminated end surface of
d, 81e, 81f, 81g, 81h, and these protruding magnetic poles 81a, 81b, ..., 81h have coils 82a, 82b, 82c, 82d, 82e, 82f, 8 respectively.
2g and 82h are wound.

The pair of projecting magnetic poles 81a, 81a,
81b and protruding magnetic poles 81c and 81d adjacent to both sides thereof
A third and a fourth radial displacement sensor 83, 84 respectively have an angle of 90 degrees in the same plane between the salient pole 81g and the salient magnetic pole 81h, and cover the laminated surface of the lower radial laminated yoke 78. The outer surface of the cover 79 is fixed to the lower radial magnetic pole ring 80 so that the outer surface of the cover 79 serves as a displacement detection surface, and the displacement is detected in the same phase as that of the first and second radial displacement sensors 55 and 56. It is arranged to do.

Reference numerals 85 and 86 are bases 3 which are stationary bodies.
3 and the lower thrust electromagnet 68 to the mounting plates 87 and 88, respectively.
A ball bearing of the vacuum environment specification in which the outer race is fixed by the inner race, the inner race of which is provided so as to have a certain gap with respect to the rotating shaft 42, and when the rotating body 38 is not magnetically levitated, the rotating body 38 Is also used as an emergency bearing.

Further, 89 is an upper shield ring which is attached to the bearing case 41 between the upper radial bearing portion 43 and the stator 59 of the electric motor 46, and 90 is provided between the stator 59 and the thrust bearing portion 45. Upper thrust electromagnet 6
7 is a lower shield ring attached to the unit 7. By providing both of these shielding rings 89 and 90, the bearing case 4
The electrical wiring inside the motor 1 is prevented from coming into contact with and damaging the rotating part such as the rotating shaft 42, and also the electrical noise generated by the electric motor 46 is shielded.

In the present embodiment thus constructed, the CV
Prior to vapor phase growth of a thin film on a semiconductor substrate in the D device 31, the upper radial bearing portion 43, the lower radial bearing portion 44 and the thrust bearing portion 45 are operated to rotate the rotating body 38.
Magnetically levitated and supported in a non-contact manner. Then chamber 3
The inside of 2 is decompressed, the rotating body 38 is rotationally driven by the electric motor 46, and the susceptor 37 is driven by the heater unit 48.
Is maintained at a predetermined temperature, the source gas is introduced into the chamber 32, and vapor phase growth is performed.

The position and the posture of the rotating body 38 are controlled while magnetically levitating and supporting the rotating body 38 in a non-contact manner, and the thrust bearing portion 4 is controlled in the thrust direction.
5 upper thrust electromagnet 67 and lower thrust electromagnet 68
By adjusting the strength of. By adjusting the thrust direction, the space between the heater unit 48 and the lower surface of the susceptor 37 facing the heater unit 48 can be changed, so that the temperature of the susceptor 37 can be adjusted. Therefore, the temperature of the semiconductor substrate can be adjusted by adjusting the thrust direction of the floating rotor 38 according to the state of vapor phase growth of the thin film, and good thin film layering can be performed.

Further, the control in the radial direction is performed by the coils 54a, 54b, ... Of the upper radial electromagnet 49 of the upper radial bearing portion 43 and the lower radial bearing portion 44.
54h, coils 82a, 8 of the lower radial electromagnet 77
This is done by adjusting the value of the current flowing through 2b, ..., 82h.

On the other hand, since the mounting position of the thrust displacement sensor 76 is away from the center of the rotary shaft of the rotary shaft 42, when the rotary body 38 is tilted, the tilt is detected by the thrust displacement sensor 76 at the same time as the axial displacement. Will be done. For this reason, if control is performed to correct the axial displacement to a predetermined value, the rotary body 38 is vibrated in the axial direction by the amount of the inclination, and stable rotation of the rotary body 38 cannot be obtained.

From the above, with respect to the inclination of the rotating body 38, the radial displacement sensors 55, 5 are controlled by the control unit.
The inclination component is calculated from the signals of 6, 83, and 84, and the signal of the thrust displacement sensor 76 is corrected according to the calculation result. This will be described below with reference to FIG.

First, from the respective values detected by the first and second radial displacement sensors 55 and 56 provided on the upper radial bearing portion 43, the values are parallel to the protruding direction of the pair of projecting magnetic poles 53a and 53b of the upper radial electromagnet 49. Displacement in different directions Δx ₁
And a pair of projecting magnetic poles 81 of the lower radial electromagnet 77 based on the respective values detected by the third and fourth radial displacement sensors 83, 84 provided on the lower radial bearing portion 44.
The displacement amount Δx ₂ in the same phase as the displacement amount Δx _{1 in the} direction parallel to the protruding direction of a and 81b is calculated.

Next, these displacement amount Δx ₁ and displacement amount Δx
_{From 2} , the amount of displacement with reference to the center of rotation at the position of the lower radial electromagnet 77 at the position of the upper radial electromagnet 49 of the rotary shaft 38 is obtained as Δx ₁ −Δx ₂ . Then, the first and second radial displacement sensors 55, 56 and the third and fourth radial displacement sensors 83,
The rotation axis direction distance between the 84 and _{l b,} and the distance from the rotation center of the thrust displacement sensor 76 and _{l s,} is [delta] amount of correction of inclination _{δ = l s / l b ×} (Δx 1 -Δx 2 ) Is calculated.

The signal of the thrust displacement sensor 76 is corrected based on the calculated inclination correction amount δ. As a result, the apparent axial displacement due to the inclination of the rotating body 38 can be canceled, and stable rotation of the rotating body 38 can be obtained.

Since the upper radial laminated yoke 50, the lower radial laminated yoke 78, and the laminated end surface of the stator core 57 may be rusted because of the above-mentioned structure. The covers 51, 61, 79 provided so that the laminated end surfaces are not exposed to the outside can prevent rust from scattering to the outside.
As a result, the inside of the chamber 32 is not contaminated by rust, and the product yield is not reduced.
Further, since the smooth outer surfaces of the covers 51 and 61 face the radial displacement sensors 55, 56, 83 and 84, accurate displacement can be detected.

Further, the rotating body 38 supported on the pressure reducing side.
Since a vacuum shield that separates the stationary body from the stationary body is not required, the force required to support the rotating body 38 in a non-contact manner is small, and the bearing portions 43, 44, 45 are miniaturized. Further, since the lower radial bearing portion 44 and the thrust bearing portion 45 are integrally provided, they do not lengthen in the axial direction, and the first, second, third and fourth radial displacement sensors 55, 56, 83, Since each of 84 is provided between the magnetic poles of the upper radial electromagnet 49 and the lower radial electromagnet 77, the thrust displacement sensor 76 is further attached between the magnetic poles of the upper thrust electromagnet 67.
Each of them does not become axially long and becomes long, and can be made very short and very compact.

It should be noted that the present invention is not limited to the above-described embodiments, but can be implemented with various modifications without departing from the scope of the invention.

[0042]

As is apparent from the above description, according to the present invention, there are provided upper and lower thrust electromagnets facing the upper and lower surfaces of the thrust disk provided on one end side of the rotating shaft of the rotating body housed in the housing. , A first radial electromagnet facing the first cover that covers the laminated end face of the first radial laminated yoke fixed to the outer peripheral portion of the thrust disk, and is attached between the magnetic poles of the first radial electromagnet. A radial displacement sensor on one end side having the outer surface of the first cover as a detection surface and a second cover facing the second cover covering the laminated end surface of the second radial laminated yoke fixed to the other end side of the rotating shaft. Of the second radial electromagnet and the radial displacement sensor on the other end side, which is attached between the magnetic poles of the second radial electromagnet and has the outer surface of the second cover as a detection surface, thereby contaminating the inside of the housing. Can be reduced and miniaturized magnetism An effect that it is possible to provide a receiving device.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a main part of a CVD apparatus according to an embodiment of the present invention.

FIG. 2 is a sectional view showing the outline of the overall configuration of a CVD apparatus according to an embodiment of the present invention.

FIG. 3 is a vertical sectional view of a rotor according to an embodiment of the present invention.

FIG. 4 is a vertical cross-sectional view of an upper radial laminated yoke portion of the upper radial magnetic bearing portion according to the embodiment of the present invention.

FIG. 5 is a vertical cross-sectional view of a lower radial laminated yoke portion of the lower radial magnetic bearing portion according to the embodiment of the present invention.

FIG. 6 is a cross-sectional view of an upper radial magnetic bearing portion according to an embodiment of the present invention.

FIG. 7 is a cross-sectional view of a lower radial magnetic bearing portion according to an embodiment of the present invention.

8A and 8B are views for explaining the detection of displacement by the displacement sensor according to the embodiment of the present invention, and FIG. 8A is a diagram for explaining the displacement detected by the radial displacement sensor.
(B) is a figure explaining the displacement which a radial displacement sensor and a thrust displacement sensor detect.

FIG. 9 is a sectional view showing a schematic configuration of a main part of a CVD apparatus using a conventional ball bearing.

FIG. 10 is a cross-sectional view showing a schematic configuration of a main part of a CVD apparatus using a conventional magnetic bearing.

[Explanation of symbols]

32 ... Chamber 38 ... Rotating body 42 ... Rotating shaft 49 ... Upper radial electromagnet 50 ... Upper radial laminated yoke 51, 79 ... Cover 53a, 53b, 53c, 53d, 53g, 53h, 8
1a, 81b, 81c, 81d, 81g, 81h ... Projective magnetic pole 55 ... First radial displacement sensor 56 ... Second radial displacement sensor 66 ... Thrust disk 69 ... Upper thrust electromagnet 70 ... Lower thrust electromagnet 76 ... Thrust displacement Sensor 77 ... Lower radial electromagnet 78 ... Lower radial laminated yoke 83 ... Third radial displacement sensor 84 ... Fourth radial displacement sensor

Claims (2)

[Claims] 1. A vertical type rotating body housed in a housing and provided with a thrust disk on one end side of a rotating shaft, and magnetic poles opposed to each other with a gap provided above and below the thrust disk. Upper and lower thrust electromagnets for supporting the body in the thrust direction in a non-contact manner, and a thrust displacement sensor for outputting a signal for controlling the upper and lower thrust electromagnets, which is provided with the surface of the thrust disk as a detection surface, A first radial laminated yoke fixed to the outer peripheral portion of the thrust disc and having an outer peripheral laminated end surface covered with a first cover, and a magnetic pole such that a gap is formed between the outer peripheral laminated end surface of the first radial laminated yoke. And a first radial electromagnet that supports one end of the rotating body in a radial direction in a non-contact manner, and is attached between the magnetic poles of the first radial electromagnet with the outer surface of the first cover as a detection surface. First A radial displacement sensor on one end side for outputting a signal for controlling the radial electromagnet; a second radial laminated yoke fixed to the other end side of the rotary shaft and having an outer peripheral laminated end surface covered with a second cover; A second radial electromagnet for supporting the other end of the rotating body in a radial direction in a non-contact manner with the magnetic poles facing each other with a gap provided on the outer peripheral laminated end surface of the second radial laminated yoke. A radial displacement sensor on the other end side, which is attached between the magnetic poles of the radial electromagnet and has an outer surface of the second cover as a detection surface, and which outputs a signal for controlling the second radial electromagnet, is provided. Magnetic bearing device. 2. The magnetic bearing according to claim 1, wherein the thrust displacement sensor is provided between the magnetic poles of one of the upper and lower thrust electromagnets having a U-shaped cross section and an annular shape. apparatus.