JP2000220595A - Vacuum pump device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the transmission of heat from a member inside a vacuum pump device such as a turbine molecular pump or the like, e.g. from the surface of a blade such as a rotor blade or a stator blade into the blade. SOLUTION: This device is constructed in such a manner that on the blade 12 of the rotor blade 62 or the stator blade 72 of a turbine molecular pump device exposed to pump compressed heat or heat from a heater, a first layer 13 made of a heat bad conductor covering is formed, and a second layer 14 made of a heat good conductor covering is formed on the surface of the first layer 13. By the covering of this double-layer structure, the transmission of heat from the second layer 14 to the blade 2 is prevented. Thus, the surface of the blade 12 of the rotor blade 62 or the stator blade 72 is prevented from being cooled, and a semiconductor product stuck/deposited on the blade surface is smoothly sublimated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a vacuum pump device, and more particularly, to a turbo molecular pump, a drag pump and other mechanical vacuum pumps.

[0002]

2. Description of the Related Art In recent years, CVD equipment, etching equipment, and the like have become widespread as semiconductor manufacturing equipment. When a semiconductor is manufactured by these devices, a vacuum pump device is used to bring a chamber such as a CVD device into a high vacuum atmosphere. As one of the vacuum pump devices,
A non-contact rotation turbo molecular pump device for magnetically levitating the rotor is used, and SiH4, PH3, B2H6,
A process gas such as ASH3 is discharged from a chamber such as a CVD apparatus. The temperature of the process gas is between 50 ° C and 60 ° C.
It is known that when the temperature is lowered to ° C, the gas changes from a gas to a solid, and this product adheres or accumulates on the inner wall of the turbo-molecular pump device, a member forming a flow path of the process gas, or the like. If the operation is continued for a long time in this state, the deposits on the rotor blades, the stator blades, and other members forming the flow path of the process gas provided in the turbo-molecular pump increase, and as a result, the turbo-molecular The operation of the pump device may not be performed smoothly.

[0003] For this reason, the rotor blades of a turbo molecular pump,
In order to prevent the semiconductor product from adhering to the stator blade and other members forming the flow path of the process gas, the temperature of the rotor blade, the stator blade, and the like is higher than the sublimation temperature (solidification temperature) of the semiconductor product. Need to keep. As a specific method, the following method has conventionally been adopted. (1) A heating section is provided so as to increase the surface temperature of the rotor blades and the stator blades, and the temperature of a portion where the semiconductor product is to be attached and deposited on the rotor blades and the stator blades is increased. (2) A gas such as a process gas in the turbo-molecular pump locally heats the stator side of the flow path in the drawing by the heating unit.

[0004]

However, the above-mentioned conventional method has the following problems. In the above method (1), when the temperature of the rotor blades and the stator blades of the turbo molecular pump, which is a high-speed rotating body, increases, the blades of the material forming these blades generate heat from the compression heat of the pump and the heating unit for a long time. And the blade material may have a creep phenomenon or the like. As a result, there is a restriction that the temperature cannot be raised above the permissible temperatures of the rotor blades and the stator blades, and a control function with higher precision is required in order not to exceed the restriction.

In the method (2), the method (1)
In addition to the problems of the method described above, the temperature on the rotor blade side does not rise unless gas such as process gas flows into the pump and the process gas causes heat transfer from the heating unit to the rotor blades of the pump. Furthermore, even if the temperature rises due to the flow of a gas such as a process gas, it is necessary to control the gas flow rate while detecting the temperature of the rotor blades of the pump. However, such control has to limit the exhaust amount of gas in use of the pump, and there is a disadvantage to the original purpose of the vacuum pump that exhausts the gas and increases the degree of vacuum. In order to solve the above problems, the present invention prevents heat from being transmitted (dissipated) to the blades of members in a vacuum pump device, and prevents semiconductor products from adhering and accumulating on the surface of members in the vacuum pump device. The purpose is to prevent it.

[0006]

According to the present invention, there is provided a first layer comprising a poor heat conductive film and a second layer comprising a good heat conductive film formed on the first layer. Layers of
The above object is attained by a vacuum pump device characterized in that a coating having a two-layer structure is formed on a member in the vacuum pump device. According to a second aspect of the present invention, the vacuum pump device includes a rotor main body rotated by a motor, a plurality of stages fixedly arranged in a rotation axis direction of the rotor main body, and a rotary shaft of the rotor main body. A rotor blade provided with a plurality of rotor blades radially inclined at a predetermined angle with respect to the rotor body, and a plurality of stages, fixedly disposed between the rotor blades in the rotation axis direction of the rotor body, and the rotor body And a stator blade provided with a plurality of stator blades radially inclined at a predetermined angle with respect to the rotation axis of the turbo molecular pump, wherein the coating having the two-layer structure includes the rotor blade and the stator blade. The above object is achieved by the vacuum pump device according to claim 1, wherein the vacuum pump device is formed on at least one of the above.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to FIGS. (1) Outline of Embodiment A vacuum pump device, for example, a turbo molecular pump 1 is connected to a semiconductor manufacturing apparatus and operated. At this time, the process gas is sucked by the turbo molecular pump 1 and the atmosphere in the pump 1 containing the process gas is compressed, so that compression heat is generated inside the pump. On the other hand, as described above, a heating unit (not shown) provided for the rotor blade 62 or the stator blade 72 of the turbo-molecular pump 1 and a not-shown heating unit provided on the thread groove spacer portion 80 side of the gas flow path in the pump. Heat generated by the heating unit (hereinafter referred to as “heater heat”) is generated inside the pump. As a result, the temperature of the process gas to be exhausted in the pump exhaust passage is significantly increased. A first layer 13 made of a poorly conductive conductor film is formed on a blade 12 such as a rotor blade 62 or a stator blade 72 of a pump that receives the compression heat or heater heat (hereinafter referred to as “compression heat”). Tier 1
3 a second layer 1 consisting of a poor thermal conductor coating formed on
4 is formed. This first layer 1
Due to the heat-insulating action of 3, heat is not transferred (dissipated) from the second layer 14, which is the outermost layer directly receiving heat, to the blade 12, so that the high temperature is maintained. As a result, the second layer 14 is not cooled down, and the semiconductor product to be attached and deposited on the blade 12 and the like is smoothly sublimated. Further, the blade 12 can be prevented from being damaged by heat.

(2) Details of Embodiment FIG. 1 shows the overall configuration of a turbo-molecular pump 1 according to an embodiment to which the present invention is applied. The turbo molecular pump 1 is, for example, a device that is installed in a semiconductor manufacturing apparatus and discharges a process gas 100 from a chamber. In this example, it is assumed that a flange 11 is formed at the upper end of a cylindrically formed exterior body 10 and is connected to a semiconductor manufacturing apparatus (not shown) by bolts or the like. A plurality of stator blades 72 are arranged inside the exterior body 10, and a plurality of rotor blades 62 are arranged between the stator blades 72. This rotor blade 62
Are provided on the outer peripheral wall of the rotor 60, and the rotor 1 is rotated so as to rotate in conjunction with the rotor shaft 18 made of a magnetic material.
9 is fixed to the rotor shaft. The rotor 60 uses a so-called magnetic bearing.
A pair of radial electromagnets 21 are arranged opposite to each other with the rotor shaft 18 interposed therebetween, and two pairs of radial electromagnets are arranged so as to be orthogonal to each other. Two pairs of radial sensors 22 are provided adjacent to the radial electromagnet 21 and opposed to each other with the rotor shaft 18 interposed therebetween.

Further, a lower portion of the rotor shaft 18 is similarly provided.
A pair of radial electromagnets 24 are arranged, and two pairs of radial sensors 26 are provided adjacent to the radial electromagnets 24. When an exciting current is supplied to these radial electromagnets 20 and 24, the rotor shaft 18 is magnetically levitated. This exciting current is supplied to the radial sensor 2 during magnetic levitation.
The rotor shaft 18 is controlled in accordance with the position detection signals from the sensors 2 and 26 so that the rotor shaft 18 is held at a predetermined position in the radial direction. Further, a high-frequency motor 30 is disposed between the radial direction sensor 22 and the radial direction sensor 26 inside the exterior body 10. When the high-frequency motor 30 is energized, the rotor shaft 18 and the rotor blades 62 fixed thereto rotate. A disk-shaped metal disk 31 made of a magnetic material is fixed to a lower portion of the rotor shaft 18.
A pair of axial electromagnets 3 sandwiching 1 and facing each other
2, 34 are arranged. Further, an axial sensor 36 is arranged to face the cut end of the rotor shaft 18.

The exciting current of the axial electromagnets 32 and 34 is controlled in accordance with a position detection signal from an axial sensor 36, so that the rotor shaft 18 is held at a predetermined axial position. . Further, in FIG. 1, a thread groove spacer section 80 constituting the thread groove pump section,
A screw groove 81 is provided. Screw groove spacer 80
Is connected to the spacer 71 and is disposed below the spacer 71 and the stator blade 72. The thread groove spacer portion 80 has a thickness such that the inner diameter wall protrudes to a position close to the outer peripheral surface of the rotor main body 61, and a plurality of thread grooves 81 having a helical structure are formed on the inner diameter wall. This screw groove 81
Are communicated between the stator blades and the rotor blades, so that the transferred and discharged gas is introduced into the screw grooves 81. In this embodiment, the screw groove 8 is used.
Although 1 is formed on the stator 70 side, the thread groove 81 may be formed on the outer diameter wall of the rotor main body 61. Further, the screw groove 81 can be formed on the outer diameter wall of the rotor main body 61 while being formed on the screw groove spacer portion 80.

FIG. 2 shows a rotor or stator blade 12 disposed in the turbo-molecular pump 1 of FIG.
FIG. 9 is a cross-sectional view of a rotor blade or a stator blade 62 ′ or 72 ′ in the direction of a rotor rotation axis 90 in which two-layer coatings 13 and 14 of the present invention are formed on (rotor blade 62, stator blade 72). In the figure, the blade blade surface receives compression heat or the like from the direction of arrow A, for example. As shown in FIG. 2, in the present embodiment, the rotor blade or stator blade 12 (rotor blade 62, stator blade 7
2) On top of the first layer 13 having a low thermal conductivity
(Hereinafter, referred to as “heat-defective conductor layer 13”),
A second layer having a high thermal conductivity (hereinafter, referred to as “thermally conductive layer 14”) is formed thereon as a second layer.

As the material of the first heat-defective conductor layer 13, ceramics having heat insulating properties or heat resistance and heat resistance (for example, ThO2, ZrO2, K2O.nTiO2,
CaO, SiO2, etc.) and resin (for example, Teflon resin,
Acrylic resin, epoxy resin, etc.) are preferred. Also,
In the layer of the heat-defective conductor layer 13, a material having many small spaces therein may be used. Further, the material having such a space inside may be a layer whose periphery is covered with the above-mentioned ceramics. The rotor blade or the stator blade 12 (rotor blade 62, stator blade 7
2) As a method for forming the coating layer 13 thereon, enamel treatment, melting treatment, thermal spraying, electrostatic coating, electrodeposition coating, spray coating, CVD, or the like is suitable. Second thermal conductive layer 14
As a material of the metal, aluminum, copper, or the like, which is a metal material, is preferable. The melting points of these materials need to be higher than the temperature of the gas in the turbo-molecular pump 1. Further, the metal material of the second layer 14 is likely to undergo thermal expansion and thermal contraction due to the influence of temperature change due to the heat of pump compression in the turbo-molecular pump 1. Therefore, a ductile material is preferable. As a method for forming the second layer 14 using these metal materials, surface treatments such as electroless plating, electroplating, vacuum deposition, and ion plating are suitable.

The thickness of each layer is from 10 μm to 5 m
m is preferable, and 50 to 100 μm is more preferable. However, if possible, the blade 12 (62, 7
In order to prevent heat from being transmitted to 2), it is preferable to form the first layer 13 which is a thermally defective conductor layer thicker. On the other hand, the second layer 14 only needs to have a film thickness necessary and sufficient to maintain the heat capacity for maintaining the temperature at which the semiconductor product is sublimated by the process gas. Also, in general, the coating is
As the thickness increases, the internal stress increases, and swelling and peeling of the film are easily caused.
It should be noted that a layer structure having more than two layers may be formed to prevent the heat from being further transmitted to the blade 12 (62, 72). However, the outermost layer that directly receives heat needs to be a heat conductive layer.

FIG. 3 shows a first embodiment in which a two-layer coating of the present invention is formed on the wall surface on the rotor blade side of the turbo molecular pump shown in FIG. The shaded portion in FIG. 3 is a portion to which a coating having a two-layer structure is applied. During operation of the turbo molecular pump 1,
The rotor 61 rotates at high speed, and the rotor blades 62 and the stator blades 7
The second blade 12 receives the process gas heated to a high temperature due to the heat of compression or the like from the direction of the intake port indicated by the arrow A in FIG. At this time, the outermost layer 14, which is the second layer of the blade 62, becomes hot due to compression heat and the like. However, in the present embodiment, since the first layer 13 is a poor conductor of heat, the compression heat or the like is not transmitted to the rotor blade 12 of the rotor blade 62 ′ on which the two-layer coating of the present invention is applied, or Difficult to communicate. As a result, the rotor blade 12 of the rotor blade 62 'provided with the two-layer coating of the present invention is not adversely affected by the creep phenomenon or the like. In particular, if a semiconductor product adheres to and accumulates on the tip end portion 200 of the rotor blade 12, the semiconductor product is likely to come into contact with other members, or the balance of the entire wing is lost when the rotor 60 rotates at high speed. It is particularly preferable to apply a film of As a result, if there is no adhesion or deposition of semiconductor products, ABS (Automatic Balan) which has been conventionally provided as necessary is used.
In particular, a sing system circuit is not required.

Further, in the turbo-molecular pump 1,
In particular, the closer to the downstream side in the pump 1, the narrower the gap between the blades is, and the above-mentioned problem attributed to the attachment of semiconductor products is likely to occur. In order to solve the problem, the coating of the present invention may be selectively formed on the downstream blade blade. Furthermore,
A coating can also be applied to the inner wall portion 250 of the lower part of the rotor downstream of the pump 1. FIG. 4 shows an embodiment in which the two-layer coating of the present invention is formed on the wall surface on the stator blade side and the wall surface on the exhaust port of the turbo-molecular pump 1 in FIG. The shaded portion in FIG. 4 is the portion where the coating is applied. The stator blades 72 are the same as described above for the rotor blades 62 in FIG. Further, in this embodiment, similarly, the surface 251 of the member facing the inner wall of the rotor 60 on the downstream side of the pump 1, the thread groove spacer portion constituting the thread groove pump portion, the wall 300 of the thread groove, and the inner wall of the exhaust port 350. The film of the present invention is also formed.

In FIG. 3 or FIG. 4 (each member and device are the same as in FIG. 1), the coating is formed on the entire rotor blade 60 or the stator blade 72, but a part thereof is formed. Only the rotor blade 60 and the stator blade 72 may be formed entirely or partially. Further, as shown in FIG. 4, a coating may be selectively formed on a portion other than the wing, such as the wall surface 350 of the exhaust port. The embodiment described above is not limited to the application to the turbo-molecular pump 1, but can be applied to a drag pump and other mechanical vacuum pumps in general. These embodiments have the following effects.

(1) The two-layer coating of the present invention is applied.
The second layer 14, which is a coating having a high thermal conductivity that forms the surface of the rotor blade 62 'or the stator blade 72', receives compression heat or the like, and the temperature is improved. However, the first layer 13, which is a film having low thermal conductivity, sandwiched between the blade 12 and the second layer 14 does not transmit heat to the blade 12 or makes it difficult to transmit heat. Therefore, the blade 12 does not undergo thermal deformation or creep, and the rotor blade 62 ′ or the stator blade 72 ′ provided with the two-layer coating of the present invention.
Has improved durability against heat. Furthermore, the second layer 14, which is the surface layer of the rotor blade 62 'or the stator blade 72', on which the two-layer coating of the present invention is applied, is not cooled, and the semiconductor product to be attached and deposited on the blade surface is not cooled. Sublimation is performed smoothly. (2) Since the heat conduction between the second layer 14 of the good thermal conductor and the blade 12 is suppressed by the first layer 13 of the heat-defective conductor, the blades can be formed without lowering the temperature of the second layer 14. The blade can be cooled.

(3) Even if the heat for sublimating the semiconductor product to be deposited on the wing surface is equal to or higher than the heat resistant temperature of the blade 12, the heat insulating effect of the first layer 13 causes the blade 12 to adhere to the wing surface. Can be applied above the heat resistant temperature of the material forming As a result, the exact temperature within the turbo-molecular pump 1 for sublimating the semiconductor product that is to be deposited on the surface of the rotor blade 62 'or the stator 72' blade on which the two-layer coating of the present invention has been applied. No control is required. That is, the blade 12 (62, 7
The surface temperature of the blade or the like can be set high without being limited to the permissible temperature of 2) and adheres to the rotor blade 62 'or the stator 72' blade on which the two-layer coating of the present invention is applied. Sublimation of the intended semiconductor product is promoted. (4) The rotor blade 6 provided with the two-layer coating of the present invention.
Heat can not be transmitted to the surfaces exposed to the high-temperature process gas, such as the inner walls 250 and 350 of the turbo molecular pump 1 other than the 2 ′ or stator 72 ′ blades, or the heat can be hardly transmitted. Therefore, the semiconductor products to be attached and deposited on these portions are smoothly sublimated without being affected by the heat in these portions. Therefore, the number of times of regular cleaning of the inside of the turbo molecular pump 1 is reduced, and the maintenance cost can be reduced.

[0019]

As described above, according to the vacuum pump device of the present invention, it is possible to prevent the transmission of compression heat and the like from the heat conductive coating to the blades of the members in the vacuum pump device, and to reduce the compression heat and the like. No adverse effects such as a reduction in the material strength of the blade are eliminated. In addition, semiconductor products due to the process gas are also sublimated smoothly.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a turbo-molecular pump device to which an embodiment of the present invention is applied.

FIG. 2 is an embodiment of the present invention and is a vertical sectional view of a coating structure when applied to a rotor blade or a stator blade of the turbo-molecular pump according to the present invention.

FIG. 3 is a sectional view of the turbo-molecular pump applied to the rotor blade side of the turbo-molecular pump according to the embodiment of the present invention.

FIG. 4 is a cross-sectional view of the turbo-molecular pump applied to the stator blade side of the turbo-molecular pump according to the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Turbo molecular pump 12 Rotor blade or stator blade 13 First layer coating 14 Second layer coating 62 Rotor blade 62 'Rotor blade 72 provided with two-layer coating of the present invention 72 Stator blade 72' of the present invention Stator blade with two-layer coating

Claims (2)

[Claims] A first layer comprising a poor thermal conductor coating;
A vacuum pump device, wherein a coating having a two-layer structure of a second layer of a good heat conductive coating formed on the first layer is formed on a member in the vacuum pump device. 2. A vacuum pump device comprising: a rotor main body rotated by a motor; and a plurality of stages fixedly arranged in a rotation axis direction of the rotor main body.
A rotor blade provided with a plurality of rotor blades radially inclined at a predetermined angle with respect to a rotation axis of the rotor body; and a plurality of stages, fixed between the rotor blades in the rotation axis direction of the rotor body. Disposed, and a stator blade provided with a plurality of stator blades radially inclined at a predetermined angle with respect to the rotation axis of the rotor body, a turbo molecular pump device comprising: The vacuum pump device according to claim 1, wherein the coating is formed on at least one of the rotor blade, the stator blade, and the exhaust passage.