WO2008065798A1

WO2008065798A1 - Vacuum pump

Info

Publication number: WO2008065798A1
Application number: PCT/JP2007/068070
Authority: WO
Inventors: Takashi Kabasawa; Yoshiyuki Sakaguchi
Original assignee: Edwards Japan Limited
Priority date: 2006-11-30
Filing date: 2007-09-18
Publication date: 2008-06-05
Also published as: JPWO2008065798A1; JP5463037B2

Abstract

To properly prevent backflow of particles into an upstream region of an inlet opening without involving significant fall in gas discharge performance. A chamfered face (28a) is formed on a rotary blade (28) of a turbo molecular pump by chamfering a corner portion formed by a surface (28b) facing the upstream direction of gas transferred from the inlet opening (5) to a discharge opening (6) and a surface (28c) facing the downstream direction of the gas. The chamfered face (28a) is formed in parallel with the axial direction of a shaft (7). In the turbo molecular pump (1), the region where the chamfered face (28a) of the rotary blade (28) isformed is determined based on the interval of adjacent rotary blades (28), moving speed of the rotary blade (28), and a region L with which particles are possible to collide and that is specified by moving speed etc. of the particles. In other words, the amount of cutting in the chamfering work of the corner portion formed by the face (28b) and the face (28c) of the rotary blade (28) is determined based on the region L with which the particles are possible to collide.

Description

Specification

Technical field of vacuum pump

The present invention relates to, for example, a vacuum pump that performs evacuation processing of a vacuum vessel, and more particularly, to a vacuum pump having a structure that prevents backflow of particles to a vacuum container. Background art

[0002] Vacuum pumps such as turbo molecular pumps and thread groove pumps are widely used in, for example, vacuum vessels that require high vacuum, such as exhaust of semiconductor manufacturing equipment and electron microscopes.

A vacuum pump that realizes this high vacuum environment includes a casing that forms an exterior body having an intake port and an exhaust port. And inside the casing, there is housed a structure that allows the vacuum pump to exert its exhaust function! A structure that exhibits this exhaust function is roughly composed of a rotating part (rotor part) rotatably supported by a shaft and a fixed part (stator part) fixed to the casing.

[0003] In the case of a turbo molecular pump, a rotating part is composed of a rotating shaft and a rotating body fixed to the rotating shaft, and rotor blades provided with radial blades are arranged in multiple stages on the rotating body. Yes. In addition, stator blades are arranged in multiple stages in the fixed portion alternately with respect to the rotor blades.

Also, a motor for rotating the rotating shaft at high speed is provided. When the rotating shaft rotates at a high speed by the function of this motor, gas is sucked from the intake port by the action of the rotor blade and the stator blade, and the exhaust port Power is being discharged.

[0004] By the way, particles generated in the vacuum container such as fine particles made of reaction products generated in the process chamber of the semiconductor manufacturing apparatus are also taken into the vacuum pump only from the gas in the vacuum container.

When the particles collide with the rotor blade rotating at high speed inside the vacuum pump, the particles are bounced back to the vacuum vessel, that is, flow back from the suction port to the vacuum vessel. Particles flowing back from the vacuum pump is a fear force ^s the internal contamination cause of the vacuum vessel. Therefore, conventionally, a technique for suppressing the backflow of particles to the vacuum vessel side has been proposed in the following patent documents!

Patent Document 1: Japanese Unexamined Patent Application Publication No. 2006-307823

[0005] In Patent Document 1, in order to prevent particles colliding with the rotor blades from being bounced back to the intake port side, the tip surface force of the blades of the rotor blades is parallel to the rotational axis direction or the exhaust gas is exhausted. A turbo-molecular pump formed to face the mouth side has been proposed. FIG. 5 is a developed view schematically showing the rotor blades in the turbo molecular pump proposed in Patent Document 1. As shown in FIG.

Specifically, Patent Document 1 discloses a rotor blade formed such that a surface 108a of a blade 108 is parallel to the direction of the rotation axis, as shown in FIG.

By forming the surface 108a of the blade 108 in this way, it is possible to prevent particles from colliding with the conventional surface 108b of the blade 108 and being bounced back to the inlet side. Disclosure of the invention

Problems to be solved by the invention

[0006] However, when the blade 108 of the rotor blade is processed as proposed in Patent Document 1 for the purpose of preventing the backflow of particles, the rotor blade is effective in the exhaust treatment of gas molecules (gas molecules). This will reduce the area of the vacuum pump, which will reduce the exhaust performance of the vacuum pump.

[0007] Here, a mechanism that causes a reduction in the exhaust performance of the vacuum pump when the blade 108 of the rotor blade is machined as proposed in Patent Document 1 will be described. Fig. 6 (a) shows an example of the movement path of gas molecules entering the rotor blades from the inlet side when the blade 108 is not processed, and Fig. 6 (b) shows the blade 10 8 is a diagram showing an example of a movement path of gas molecules incident on a rotor blade from the inlet side when processing is performed on FIG.

Fig. 7 (a) is a diagram showing an example of the movement path of gas molecules incident on the rotor blades from the exhaust port side when the blade 108 is not processed. Fig. 7 (b) FIG. 4 is a diagram showing an example of a movement path of gas molecules incident on a rotor blade from an exhaust port side when a blade is processed. 6 and 7 show the state when gas molecules are incident from one power point in order to avoid complicated explanation.

[0008] As shown in FIG. 6 (b), when the gas molecules incident from the intake port collide with the surface 108a of the blade 108, the gas molecules are not sent to the exhaust port side, but are sent to the adjacent blade 108. It leans toward the intake side and collides with the side surface 108c and bounces back to the intake side.

As shown in Fig. 7 (b), when gas molecules incident from the exhaust port collide with the surface 108a of the blade 108, the gas molecules are not sent to the exhaust port side, and are not sent to the exhaust port side. It collides with the side surface 108c and bounces back to the inlet side.

In addition, as shown in FIG. 7B, when the gas molecules incident from the exhaust port side do not collide with the blade 108, the gas molecules are sent to the intake port side as they are.

[0009] When FIG. 6 (a) is compared with FIG. 6 (b), the processing of the blade 108 reduces the probability (Ml 2) that gas molecules pass from the intake port side to the exhaust port side. I understand.

In addition, comparing Fig. 7 (a) and Fig. 7 (b), it can be seen that processing the blade 108 increases the probability (M21) that gas molecules pass from the exhaust port side to the intake port side. . The gas exhaust speed in the vacuum pump is expressed by the following equation.

Exhaust velocity = C X (M12— Μ21) ············· 1 where C is the number of incident gas molecules. By processing the blade 108 to provide the surface 108a, the value of M12 in Equation 1 is decreased and the value of M21 is increased, so that the exhaust speed is decreased. Such a decrease in the exhaust speed causes a decrease in the exhaust performance of the vacuum pump.

[0010] Therefore, the present invention provides a vacuum pump that can appropriately prevent the backflow of particles (particles) to the upstream region of the intake port without significantly reducing the exhaust performance. To do.

Means for solving the problem

[0011] In the invention according to claim 1, an exterior body having an intake port and an exhaust port, a rotating body included in the exterior body and rotating at high speed, and a moving blade row having a blade angle provided in the rotating body are provided. A plane parallel to the axial direction of the rotating body, or a corner formed by a surface of the blade that faces the upstream direction of the gas transferred from the intake port to the exhaust port, or A rotating blade formed with a chamfered surface having a surface facing the downstream direction of the gas, The object is achieved.

In the invention according to claim 1, the rotating blade is, for example, protruded from at least one part of the side surface of the rotating body so as to be inclined with respect to the rotation axis direction, and faces the inlet side. It is preferable that the corner portion formed by the surface and the surface facing the rotation direction has a chamfered surface that is parallel to the axial direction of the rotating body or a surface facing the exhaust direction.

Further, in the invention according to claim 1, the rotating blade includes, for example, a surface facing an upstream direction of a gas transferred from the intake port to the exhaust port and a surface facing a downstream direction of the gas. Among the corners formed, a chamfered surface having a surface parallel to the axial direction of the rotating body or a surface facing the downstream direction of the gas is formed at the corner formed on the inlet side. It is preferable.

According to a second aspect of the present invention, in the vacuum pump according to the first aspect, the vacuum pump is a device that performs an evacuation process of a vacuum vessel, and the rotating blade is at least the interval between the adjacent rotating blades and the rotation. The chamfered surface is formed in a colliding area of particles flying from the vacuum vessel, which is specified based on the moving speed of the blade and the moving speed of the particles.

In the invention according to claim 2, it is preferable that the chamfered surface is formed only in a collision possible region, for example!

According to a third aspect of the present invention, in the vacuum pump according to the first or second aspect, of the fixed portions forming the flow path of the gas transferred from the intake port to the exhaust port, the parallel to the axial direction. A backflow prevention surface facing the downstream direction of the gas is formed in a region having a side surface.

According to a fourth aspect of the present invention, in the vacuum pump according to the third aspect, there is provided a stationary blade row fixed to the exterior body, and a positioning function of the stationary blade row, provided inside the exterior body. The backflow prevention surface is provided on at least one of the inner wall surface of the spacer and the exterior body.

The invention according to claim 5 is characterized in that, in the vacuum pump according to claim 3 or claim 4, the backflow prevention surface forms a V-shaped groove with a surface orthogonal to the rotation axis. To do. The invention's effect

[0012] According to the present invention, by forming a chamfered surface facing the direction in which particles do not flow backward at the corner portion on the inlet side of the rotating blade, the backflow of particles is prevented at a portion where the incidence of particles is concentrated. Therefore, the backflow of particles can be efficiently prevented without significantly reducing the exhaust performance.

Note that the incidence of particles is concentrated on the corner of the rotating blade on the inlet side because the rotating body rotates at a high speed and the incident angle of the particles incident on the rotating blade is extremely small.

FIG. 1 is a diagram showing a schematic configuration of a turbo molecular pump according to the present embodiment.

FIG. 2 is a development view schematically showing a part of a moving blade row in the turbo molecular pump according to the present embodiment.

FIG. 3 is an explanatory diagram for explaining a method of calculating a collision possible region L.

FIG. 4 is an enlarged view of the rupture part A in FIG.

FIG. 5 is a development view schematically showing rotor blades in a turbo molecular pump proposed in Patent Document 1.

[Fig. 6] (a) is a diagram showing an example of the movement path of gas molecules incident on the rotor blades from the air inlet side when the blade is not processed, and (b) is a diagram showing the blade being processed. FIG. 5 is a diagram showing an example of a movement path of gas molecules incident on a rotor blade from the inlet side in the case of

[Fig. 7] (a) is a diagram showing an example of a movement path of gas molecules incident on the rotor blades from the exhaust port side when the blade is not processed, and (b) is a diagram showing the processing of the blade. FIG. 5 is a diagram showing an example of a movement path of gas molecules incident on a rotor blade from the exhaust port side in the case of

Explanation of symbols

[0014] 1 turbo molecular pump

2 Casing

3 base 4 Rotor part

5 Inlet

6 Exhaust vent

7 Shaft

8 Rotor blade row

9 Cylindrical member

10 volts

11 Motor section

12 ~; 14 Magnetic bearing

15 ～ 17 Displacement sensor

18 Stator blade row

19 Thread groove spacer

20 Spacer

21 Stator column

22 m

26 Cooling pipe

28 Rotating blade

30

108 blades

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to FIGS. In this embodiment, a turbo molecular pump is used as an example of a vacuum pump. FIG. 1 is a diagram showing a schematic configuration of a turbo molecular pump 1 according to the present embodiment. FIG. 1 shows a cross-sectional view of the turbo molecular pump 1 in the axial direction.

In the present embodiment, as an example of a turbo molecular pump, a so-called composite wing type molecular pump including a turbo molecular pump part T and a thread groove type pump part S will be described as an example. Note that the present embodiment may be applied to a pump having only the turbo-molecular pump portion T or a pump having a thread groove provided on the rotating body side. The casing 2 forming the exterior body of the turbo molecular pump 1 has a cylindrical shape, and constitutes the exterior body of the turbo molecular pump 1 together with the base 3 provided at the bottom of the casing 2. A structure that allows the turbo molecular pump 1 to perform an exhaust function, that is, a gas transfer mechanism, is housed inside the exterior of the turbo molecular pump 1.

These structures that exhibit the exhaust function are roughly composed of a rotor portion 4 that is rotatably supported and a stator portion that is fixed to the casing 2.

In addition, the intake port 5 side is composed of a turbo-molecular pump part T, and the exhaust port 6 side is composed of a thread groove type pump part S! /.

[0017] The rotor section 4 includes a moving blade row 8 composed of a plurality of rotating blades 28 inclined at a predetermined angle from a plane perpendicular to the axis of the shaft 7 and extending radially from the shaft 7, on the intake port 5 side ( It is installed in the turbo molecular pump section T). The rotor portion 4 is made of a metal such as stainless steel or aluminum alloy.

Further, the rotor part 4 is provided with a cylindrical member 9 made of a member having a cylindrical outer peripheral surface on the exhaust port 6 side (screw groove type pump part S).

Further, the turbo molecular pump 1 has a plurality of moving blade rows 8 formed in the axial direction.

[0018] The shaft 7 is a rotating shaft (rotor shaft) of the cylindrical member. A rotor portion 4 is attached to the upper end of the shaft 7 by a plurality of bolts 10.

In the middle of the axial direction of the shaft 7, a motor part 11 for rotating the shaft 7 is arranged! / In addition, the shaft 7 is arranged in the radial direction on the intake port 5 side and the exhaust port 6 side of the motor unit 11. A magnetic bearing portion 12 and a magnetic bearing portion 13 for supporting the shaft are provided.

Furthermore, a magnetic bearing portion 14 for supporting the shaft 7 in the axial direction (thrust direction) is provided at the lower end of the shaft 7.

The shaft 7 is supported in a non-contact manner by a 5-axis control type magnetic bearing composed of magnetic bearing portions 12, 13, and 14.

Displacement sensors 15 and 16 are formed in the vicinity of the magnetic bearing portions 12 and 13, respectively, so that the radial displacement of the shaft 7 can be detected. In addition, a displacement sensor 17 is formed at the lower end of the shaft 7 so that the axial displacement of the shaft 7 can be detected. I'm getting ready.

A stator portion is formed on the inner peripheral side of the casing 2. This stator part includes a stationary blade row 18 provided on the intake port 5 side (turbomolecular pump part T), and a thread groove spacer 19 provided on the exhaust port 6 side (thread groove type pump part S). It is composed of

The stationary blade row 18 is composed of blades that are inclined at a predetermined angle from a plane perpendicular to the axis of the shaft 7 and extend from the inner peripheral surface of the casing 2 toward the shaft 7. In the turbo-molecular pump section T, the stationary blade rows 18 are formed in a plurality of stages alternately in the axial direction with the moving blade rows 8. The stationary blade rows 18 of each stage are separated from each other by a cylindrical spacer 20.

[0020] The thread groove spacer 19 is a cylindrical member in which a spiral groove is formed on the inner peripheral surface. The inner peripheral surface of the thread groove spacer 19 faces the outer peripheral surface of the cylindrical member 9 with a predetermined clearance (gap) therebetween. The direction of the spiral groove formed in the thread groove spacer 19 is the direction toward the exhaust port 6 when the gas is transported through the spiral groove in the rotational direction of the rotor portion 4. The depth of the spiral groove becomes shallower as it approaches the exhaust port 6. The gas transported through the spiral groove is compressed as it approaches the exhaust port 6.

These stator portions are made of metal such as stainless steel or aluminum alloy. The base 3 and the casing 2 constitute an exterior body of the turbo molecular pump 1. At the center of the base 3 in the radial direction, a stator column 21 having a cylindrical shape is attached concentrically with the rotation axis of the rotor.

[0021] A back cover 22 is attached to the bottom of the base 3 (the opening of the stator column 21).

The turbo molecular pump 1 according to the present embodiment is provided with a control device for controlling the turbo molecular pump 1 as shown in FIG.

While the turbo molecular pump 1 is in operation, the rotor section 4 rotates at a high speed, and the blades of the moving blade row 8 and the stationary blade row 18 receive a process gas that has been heated to high temperature by compression heat or the like. In response to the heat of compression, the blade temperature of the moving blade row 8 and the stationary blade row 18 rises.

Further, the turbo molecular pump 1 is heated by heat generated from the motor unit 11 and becomes a high temperature state.

In this way, the turbo molecular pump 1 is operated by the collision heat (compression heat) of gas molecules and the motor unit 11. It is in a high temperature state due to heat generation.

Therefore, a cooling pipe 26 is embedded in the base 3 in order to cool the turbo molecular pump 1 in a high temperature state.

The cooling pipe 26 is made of a tubular (tubular) member. The cooling pipe 26 is a member that cools the periphery of the cooling pipe 26 by flowing a cooling medium, which is a heat medium, into the cooling pipe 26 so that the cooling medium absorbs heat.

[0022] The cooling pipe 26 described above is composed of a member having a low thermal resistance, a member, that is, a member having a high thermal conductivity, and a member such as copper or stainless steel.

Further, the coolant flowing through the cooling pipe 26, that is, the fluid for cooling the object may be a liquid or a gas. As the liquid coolant, for example, water, a calcium chloride aqueous solution, an ethylene glycol aqueous solution, or the like can be used. For example, ammonia, methane, ethane, halogen, helium gas, carbon dioxide gas, air, etc. can be used as the gas coolant.

In the present embodiment, the position of the force cooling pipe 26 in which the cooling pipe 26 is disposed on the base 3 is not limited to this. For example, it may be provided so as to be directly embedded in the stator column 21 and the back cover 22.

[0023] The turbo molecular pump 1 having such a configuration is a vacuum pump for performing an exhaust process on a vacuum vessel, for example, a process chamber provided in a semiconductor manufacturing apparatus in which the inside is kept in a high vacuum state. It is used as

Inside a process chamber of a semiconductor manufacturing apparatus, for example, particles (fine particles) made of reaction products are generated during reaction of a process gas.

Therefore, in the turbo molecular pump 1, particles generated in the process chamber that includes only the gas in the process chamber (vacuum vessel) are also taken in from the intake port 5. When particles taken in from the intake port 5 collide with the rotating blade 28 rotating at high speed inside the turbo molecular pump 1, they are bounced back to the process chamber side, that is, flow back from the intake port 5 to the process chamber side. End up.

Such particles flowing back from the turbo molecular pump 1 may cause contamination inside the process chamber. In view of this, in the turbo molecular pump 1 according to the present embodiment, the rotary blade 28 is processed so as to suppress the backflow of the particles taken in from the intake port 5 to the upstream region.

FIG. 2 is a developed view schematically showing a part of the moving blade row 8 in the turbo molecular pump 1 according to the present embodiment.

As shown in FIG. 2, the rotating blade 28 has a corner formed by a surface 28b facing the upstream direction of the gas transferred from the intake port 5 to the exhaust port 6 and a surface 28c facing the downstream direction of the gas. Then, the chamfered surface 28a is formed by chamfering!

The chamfered surface 28a is formed in parallel with the axial direction of the shaft 7, that is, in parallel with the rotation axis.

The chamfering process is, for example, a knife edge portion such as a corner formed by the surfaces 28b and 28c of the rotating blade 28 in order to prevent injury and reduce burrs when the turbo molecular pump 1 is assembled. The process which cuts a ridge angle a little is shown.

[0025] Further, in the turbo molecular pump 1 according to the present embodiment, it is specified by the interval between the adjacent rotating blades 28, the moving speed of the rotating blades 28 (rotating speed of the moving blade row 8), the moving speed of particles, and the like. The formation region of the chamfered surface 28a of the rotary blade 28 is set based on the particle collision possible region L (hereinafter referred to as the collision possible region).

That is, on the basis of the collision possible region L, the amount of bracing in the chamfering process of the corner portion formed by the surfaces 28b and 28c of the rotary blade 28 is set.

Next, a method for calculating the collision possible area L will be described.

FIG. 3 is an explanatory diagram for explaining a method of calculating the collision possible region L.

Here, as an example of the calculation method, the case where the turbo molecular pump 1 is arranged at the lower part of the exhaust port of the process chamber in a direction where the vertical line and the rotation axis direction coincide with each other will be described. Calculation of the collision possible region L Assuming that the ceiling of the process chamber is assumed as a condition, particles will fall freely from above the lm of the turbo molecular pump 1.

In addition, the angular velocity of the moving blade row 8 (rotating blade 28) is 2830 rad / s (450 rotations per second), and the radius of the rotating blade 28 (the tip having the widest interval between the rotating blades 28) is 0.15 m. The interval between the blades 28 shall be 0 · 03m.

[0027] The moving speed of the particle P, that is, the falling speed VI is calculated as follows based on the law of conservation of energy. However, the gravitational acceleration is assumed to be 9.8 [m / s2].

Fall velocity VI = ^ (2 X gravity acceleration X height) = ^ (2 X 9 · 8 [m / s2] X l

[m]) = 4.4 [m / s] The rotational speed V2 of the rotary blade 28 is as follows.

Rotational speed V2 = Radius of rotating blade 28 X Angular speed of rotating blade 28 = 0.15 [m] X 2830 [rad / s] = 423 [m / s] Particle fall speed VI and Rotating blade 28 rotational speed V2 Then, the relative velocity V3 of the particle viewed from the rotary blade 28 shown in FIG. 3 is obtained. The collision possible area L is calculated as follows.

Collision possible region L = Spacing blade interval X (falling speed VI / rotating speed V2)

= 0. 03 [m] X (4.4 [m / s] / 423 [m / s]) = 0. 0003 [m]

= 0. 3 (mm) In this way, particles falling from the process chamber collide with the rotating blade 28 within a range of only 0.3 mm from the end face of the rotating blade 28 on the inlet 5 side.

For example, if particles fall from a protective net provided at the intake port 5 of the turbo molecular pump 1 or a conductance valve provided between the turbo molecular pump 1 and the vacuum vessel, the particles The fall distance of is shortened. For this reason, the collision possible region L is further reduced as the drop speed of the particles decreases.

[0028] Even if the chamfered surface 28a is formed on the rotary blade 28 beyond the range of the collision possible region L, particles do not collide outside the range of the collision possible region L, so that the exhaust performance is only lowered. .

Therefore, in the turbo molecular pump 1 according to the present embodiment, the chamfered surface 28a of the rotary blade is formed in the range of the collision possible region L and is not formed beyond the range of the collision possible region L! / As you can see, the amount of chamfering is set!

As described above, in the present embodiment, the chamfered surface 28a is provided in the particle collision-possible region L in the rotating blade 28 in consideration of the path of incidence (entrance) of particles to the rotating blade 28. By forming the particles, it is possible to prevent the backflow of the particles efficiently without significantly reducing the exhaust performance.

In the present embodiment, the chamfered surface 28a of the rotary blade 28 is formed in parallel with the rotation axis. However, the direction of the chamfered surface 28a is not limited to this, and the colliding particle is moved upstream. It suffices to face in a direction that does not bounce back. For example, the chamfered surface 28a of the rotary blade 28 may be formed so as to face the downstream direction of the gas.

[0029] In the turbo molecular pump 1 according to the present embodiment, in order to further improve the effect of preventing the backflow of particles, a casing for forming a gas flow path from the intake port 5 to the exhaust port 6 is formed. On the inner surface of the spacer 20, a backflow preventing surface facing the downstream direction of the gas, that is, a trap for sending the colliding particles to the exhaust port 6 side is formed.

Fig. 4 is an enlarged view of the rupture part A in Fig. 1.

Specifically, as shown in FIG. 4, a cross section V is formed on the inner peripheral wall surface of the casing 2 in the vicinity of the intake port 5 and the inner peripheral wall surface (inner side surface) of the spacer 20 disposed in the vicinity of the intake port 5. A letter-shaped groove 30 extends along the circumferential direction.

[0030] As shown in Fig. 4, the groove 30 has a side surface (backflow prevention surface) provided on the intake port 5 side among the V-shaped side surfaces, and is provided on the exhaust port 6 side, that is, on the downstream side. It is formed to face the direction. Of the side surfaces provided in the V shape, the side surface provided on the exhaust port 6 side is formed so as to face the intake port 5 side, that is, the upstream direction.

By providing the groove 30 having the backflow prevention surface in this way, particles that collide with the chamfered surface 28a of the rotary blade 28 can be immediately sent to the exhaust port 6 side, so that the effect of preventing the backflow of the particles can be achieved. Can be improved.

In the present embodiment, the groove 30 is provided only on the inner peripheral wall surface of the casing 2 in the vicinity of the intake port 5 and on the inner peripheral wall surface of the spacer 20 disposed in the vicinity of the intake port 5. , The force forming part of the groove 30 is not limited to this! /.

For example, it may be provided on the inner peripheral wall surface of all the spacers 20.

Claims

The scope of the claims

[1] an exterior body having an intake port and an exhaust port;

A rotating body enclosed in the exterior body and rotating at a high speed;

A rotor blade row having a blade angle provided in the rotating body, and a corner portion formed by a traveling surface of the blade and a surface facing the upstream direction of the gas transferred from the intake port to the exhaust port A rotating blade formed with a chamfered surface having a surface parallel to the axial direction of the rotating body or a surface facing the downstream direction of the gas;

A vacuum pump comprising:

[2] The vacuum pump is a device for exhausting the vacuum vessel,

The rotating blade is at least in a collision possible region of particles flying from the vacuum vessel, which is specified based on an interval between adjacent rotating blades, a moving speed of the rotating blade, and a moving speed of particles. The vacuum pump according to claim 1, wherein the chamfered surface is formed.

[3] Out of the fixed part forming the flow path of the gas transferred from the intake port to the exhaust port, the gas flows in the downstream direction in a region having a side surface parallel to the axial direction. The vacuum pump according to claim 1 or 2, wherein a surface is formed.

[4] A stationary blade row fixed to the exterior body;

An annular spacer having a positioning function of the stationary blade row and provided in the exterior body;

With

4. The vacuum pump according to claim 3, wherein the backflow prevention surface is provided on at least one of an inner wall surface of the spacer and the exterior body.

[5] The vacuum pump according to claim 3 or 4, wherein the backflow prevention surface forms a groove having a V-shaped cross section together with a surface orthogonal to the rotation axis.