TWI665388B - Turbomolecular pump - Google Patents

Abstract

The invention discloses a turbo molecular pump, which comprises a casing, a rotor element, a stator element, and a reinforcing structure. The casing has a cavity. The rotor element and the stator element are both disposed in the cavity, and the rotor element is opposite to the stator element. It has a degree of freedom of rotation, wherein the rotor element includes a rotor base and a plurality of rotary wings connected to the rotor base, the stator element includes a plurality of fixed wings alternately arranged with the rotary wings, and the reinforcing structure is arranged on the rotor base and avoids a plurality of Covered area of rotating wings and multiple fixed wings. This can effectively extend the operating life of the pump.

Description

Turbo molecular pump

The invention relates to a turbo molecular pump, in particular to a turbo molecular pump with improved rotor structure.

With the rapid development of semiconductor process technology, the role of semiconductor process equipment is becoming more and more important. Among them, the pumping efficiency of the heart-turbine molecular pump of the vacuum system has also been gradually valued. The turbo molecular pump rotates the rotor relative to the stator at high speed to exhaust the gas in the processing chamber (or cavity) of the semiconductor process equipment, thereby achieving the effect of vacuum.

However, when turbomolecular pumps are applied to etching equipment, a large number of particles generated during the etching process will usually accumulate on the exhaust port and the rotor, causing a problem that the exhaust efficiency is reduced and the vacuum cannot be evacuated. To slow down the formation of deposits, most existing turbomolecular pumps use a heating method to increase the temperature of each component and prevent the particles from adhering. However, the rotors of existing turbomolecular pumps are generally made of aluminum alloy, and the temperature at which aluminum alloy can maintain crystal stability is below 100 ° C. As long as the ambient temperature is higher than 100 ° C or even the aging temperature of aluminum alloy, aluminum alloy will be Crystal precipitation reaction will begin to occur; once the turbo molecular pump is operated in a high temperature environment for a period of time, the structure of the rotor will cause irreversible strength weakening. In this case, light will cause the rotor to expand and deform, which is more serious. Will cause fatigue fracture of the rotor.

The technical problem to be solved by the present invention is to provide a turbo molecular pump that can stably and reliably operate in a high temperature environment in response to the shortcomings of the prior art.

In order to solve the above technical problems, one of the technical solutions adopted by the present invention Is: a turbo molecular pump comprising a housing, a stator element, a rotor element and a reinforcement structure. The housing has a cavity; the stator element is disposed in the cavity, wherein the stator element includes a plurality of fixed wings; the rotor element is disposed in the cavity, and has rotation relative to the stator element The degree of freedom, wherein the rotor element includes a rotor base and a plurality of rotary wings provided on the rotor base, and a plurality of the rotary wings and a plurality of the fixed wings are alternately arranged; and the reinforcing structure is provided on On the rotor seat, and avoiding a coverage area of a plurality of the rotary wings and a plurality of the fixed wings.

In an embodiment of the present invention, two ends of the casing have an air inlet and an air outlet connected to the cavity, respectively, and the rotor seat includes a first seat body and a first seat body and a second seat body. A second base body extending from the end of a base body, the first base body is adjacent to the air inlet, the second base body is adjacent to the exhaust outlet, and the outer side of the first base body is The diameter is smaller than the outer diameter of the second base body, wherein a plurality of the rotary wings are connected to the first base body.

In an embodiment of the present invention, the reinforcing structure is disposed on the second base.

In an embodiment of the present invention, the second base has a front end portion and a rear end portion extending from a distal end of the front end portion, and the rear end portion is closer to the row than the front end portion. An air port, and a thickness of the rear end portion is smaller than a thickness of the front end portion, wherein the reinforcement structure is provided around the rear end portion.

In an embodiment of the present invention, the thickness of the front end portion is h, and the thickness of the rear end portion is greater than 2 / 3h but less than h.

In an embodiment of the present invention, the rotor element further includes a high-speed spindle, and the high-speed spindle is disposed in the rotor seat, wherein the front end portion has an inner peripheral wall and an inner peripheral wall opposite the inner peripheral wall. And the inner peripheral wall is closer to the high speed spindle than the outer peripheral wall, wherein the reinforcement structure has an outer surface and the outer surface is flush with the outer peripheral wall.

In an embodiment of the present invention, the reinforcing structure is a ring structure, and The material of the reinforcing structure is titanium alloy or carbon fiber.

In an embodiment of the present invention, the turbo molecular pump further includes a power base for assembling the housing, the stator element, and the rotor element, wherein the power base has a bearing mechanism The bearing mechanism is disposed between the rotor base and the high-speed spindle, and is used to drive the rotor element through the high-speed spindle.

In an embodiment of the present invention, the turbo molecular pump further includes a heating device, and the heating device is disposed around the power base.

In an embodiment of the invention, the cavity is a vacuum cavity.

In an embodiment of the present invention, each of the fixed wings includes a plurality of stator blades, and each of the rotating wings includes a plurality of rotor blades.

One of the beneficial effects of the present invention lies in the technical solution of the turbo molecular pump provided by the present invention, which can be provided on the rotor seat through a reinforcing structure and avoids the coverage area of multiple rotating wings and multiple fixed wings In order not to affect all the high-speed dynamic characteristics and evacuation efficiency of the rotor element, to avoid the fatigue point of the rotor element from fatigue fracture in high temperature environment, and then effectively extend the operating life of the pump.

In order to further understand the features and technical contents of the present invention, please refer to the following detailed description and drawings of the present invention. However, the drawings provided are only for reference and description, and are not intended to limit the present invention.

P‧‧‧Turbo Molecular Pump

1‧‧‧ shell

11‧‧‧ Cavity

12‧‧‧air inlet

13‧‧‧ exhaust port

W1‧‧‧Inner peripheral wall

2‧‧‧rotor element

21‧‧‧rotor base

211‧‧‧First Block

212‧‧‧Second Block

2121‧‧‧Front end

2122‧‧‧ Rear

D1, D2‧‧‧thickness

22‧‧‧Rotary Wing

221‧‧‧rotor blade

23‧‧‧High-speed spindle

W21, W23‧‧‧‧peripheral wall

W22‧‧‧Inner peripheral wall

3‧‧‧ Stator element

31‧‧‧Fixed Wing

311‧‧‧ stator blade

32‧‧‧ Stator cover ring

4‧‧‧ Enhanced Structure

41‧‧‧The first strengthening layer

42‧‧‧Second Strengthening Layer

5‧‧‧ Power Base

51‧‧‧bearing mechanism

6‧‧‧Heating device

G‧‧‧gas molecule

FIG. 1 is a schematic perspective view of a turbo molecular pump according to an embodiment of the present invention.

FIG. 2 is an exploded view of a turbo molecular pump according to an embodiment of the present invention.

3 is a schematic cross-sectional view taken along the line III-III in FIG. 1.

FIG. 4 is a partial enlarged view of part IV in FIG. 3.

5 is a schematic perspective view of a rotor element and a stator element in a turbo molecular pump according to an embodiment of the present invention.

FIG. 6 is a schematic plan view of a rotor element in a turbo molecular pump according to an embodiment of the present invention.

FIG. 7 is a schematic diagram of a turbo molecular pump according to an embodiment of the present invention Illustration.

FIG. 8 is another enlarged view of part IV in FIG. 3.

9 is a schematic perspective view of a rotor element and a stator element in a turbo molecular pump according to another embodiment of the present invention.

The following is a description of specific embodiments of the "turbo molecular pump" disclosed in the present invention. Those skilled in the art can understand the advantages and effects of the present invention from the content disclosed in this specification. The present invention can be implemented or applied through other different specific embodiments, and various details in this specification can also be based on different viewpoints and applications, and various modifications and changes can be made without departing from the concept of the present invention. In addition, the drawings of the present invention are merely a schematic illustration, and are not drawn according to actual dimensions, and are stated in advance. The following embodiments will further describe the related technical content of the present invention in detail, but the disclosed content is not intended to limit the protection scope of the present invention.

It should be understood that although the terms first, second, third, etc. may be used herein to describe various elements or signals, these elements or signals should not be limited by these terms. These terms are mainly used to distinguish one element from another element, or a signal from another signal. In addition, the term "or" as used herein should, depending on the actual situation, include any one or more of the associated listed items.

[First embodiment]

Please refer to FIG. 1 to FIG. 3. A first embodiment of the present invention provides a magnetically levitated turbo molecular pump P, which mainly includes a casing 1, a rotor element 2, a certain element 3, a reinforcing structure 4, and a power. Base 5. The housing 1 has a cavity 11, and the rotor element 2 and the stator element 3 are both disposed in the cavity 11, and the rotor element 2 has a degree of freedom of rotation relative to the stator element 3. The rotor element 2 includes a rotor base 21 and a plurality of rotating wings 22 connected to the rotor base 21. The stator element 3 includes a plurality of fixed wings 31 connected to the housing 1, and the plurality of rotating wings 22 and the plurality of fixed wings 31 are alternately arranged. , Forming a tight cross-matching combination. The reinforcing structure 4 is arranged on the rotor base 21 and avoids Areas covered by the rotary wing 22 and the fixed wing 31. The power base 5 is used for assembling the housing 1, the rotor element 2 and the stator element 3, and driving the rotor element 2 to rotate at a high speed.

Specifically, the material of the casing 1 may be stainless steel, but it is not limited thereto; the casing 1 is cylindrical, and the cavity 11 is formed in a surrounding structure, wherein both ends of the casing 1 are open ends, that is, the casing 1 An air inlet 12 and an air outlet 13 are connected to the two ends of the cavity 11 respectively.

The material of the rotor element 2 may also be a high-strength aluminum alloy, but it is not limited to this; the rotor element 2 is rotated at a high speed by a high-speed spindle 23. The high-speed spindle 23 is disposed in the rotor base 21 and one end of the high-speed spindle 23 passes A connecting member (not labeled in the figure) is fixed on the rotor base 21. Further, the rotor seat 21 includes a first seat body 211 and a second seat body 212 extending from an end of the first seat body 211. The first seat body 211 is adjacent to the air inlet 12 and the second seat body 212 is adjacent. At the exhaust port 13; wherein the first base body 211 and the second base body 212 are both cylindrical, and the outer diameter of the first base body 211 is smaller than the outer diameter of the second base body 212. The plurality of rotating wings 22 are integrally formed with the first and second base bodies 211 and 212, wherein the plurality of rotating wings 22 and the outer peripheral wall W21 of the first base body 211 are connected to each other and are layered up and down. The extending direction is substantially perpendicular to the extending direction of the first and second base bodies 211, 212, that is, the plurality of rotating wings 22 extend outward in the radial direction, and the first and second base bodies 211, 212 extend in the axial direction. Extend backward.

The material of the stator element 3 may be high-strength aluminum alloy, but it is not limited to this; a plurality of fixed wings 31 and the inner peripheral wall W1 of the casing 1 are connected to each other and are layered up and down. The extending directions of the two rotating wings 22 are substantially parallel, that is, the plurality of fixed wings 31 extend radially inward. In this embodiment, the plurality of fixed wings 31 are connected to the inner peripheral wall W1 of the casing 1 through a certain cover ring 32, but it is not limited thereto.

Please refer to FIG. 5 to FIG. 7. In this embodiment, the number of the rotating wings 22 included in the rotor element 2 is eight, and each of the rotating wings 22 includes a plurality of rotor blades 221; The number of the fixed wings 31 is seven, and each of the fixed wings 31 includes a plurality of stator blades 311. Among them, the upper and lower adjacent rotary wings 22 and Among the fixed wings 31, the inclination direction of the rotor blade 221 and the stator blade 311 is opposite; and the inclination angle of the rotor blade 221 / stator blade 311 in the upper layer is different from the inclination angle of the rotor blade 221 / stator blade 311 in the lower layer. Thereby, it is possible to ensure that the gas molecules G flow irreversibly from the intake port 12 to the exhaust port 13.

Further, the preferred range of the number of rotor blades 221 included in the first-layer rotating wing 22 is 16 to 22, and the preferred range of the angle between each rotor blade 221 and a corresponding horizontal plane is 38 degrees to 45 degree. A preferred range of the number of rotor blades 221 included in the second-layer rotating wing 22 is 28 to 35, and a preferred range of an angle between each rotor blade 221 and a corresponding horizontal plane is 32 to 38 degrees. A preferred range of the number of rotor blades 221 included in the third-layer rotary wing 22 is 40 to 48, and a preferred range of an angle between each rotor blade 221 and a corresponding horizontal plane is 28 degrees to 33 degrees. A preferred range of the number of rotor blades 221 included in the fourth-layer rotating wing 22 is 40 to 48, and a preferred range of an angle between each rotor blade 221 and a corresponding horizontal plane is 28 degrees to 33 degrees. The preferred range of the number of rotor blades 221 included in the fifth-layer rotating blade 22 is 38 to 46, and the preferred range of the angle between each rotor blade 221 and a corresponding horizontal plane is 18 degrees to 26 degrees. A preferred range of the number of rotor blades 221 included in the sixth-layer rotating blade 22 is 32 to 37, and a preferred range of an angle between each rotor blade 221 and a corresponding horizontal plane is 13 degrees to 18 degrees. The preferred range of the number of rotor blades 221 included in the seventh-layer rotating blade 22 is 32 to 37, and the preferred range of the angle between each rotor blade 221 and a corresponding horizontal plane is 13 degrees to 18 degrees. The preferred range of the number of rotor blades 221 included in the eighth layer of rotating blades 22 is 32 to 37, and the preferred range of the angle between each rotor blade 221 and a corresponding horizontal plane is 13 degrees to 18 degrees.

In addition, the preferred range of the number of stator blades 311 included in the first-layer fixed wing 31 is 25 to 32, and the preferred range of the angle between each stator blade 311 and a corresponding horizontal plane is 38 degrees to 45 degrees. . Covered by the second fixed wing 31 A preferred range of the number of enclosed stator blades 311 is 38 to 46, and a preferred range of an angle between each stator blade 311 and a corresponding horizontal plane is 32 degrees to 38 degrees. A preferred range of the number of stator blades 311 included in the third-layer fixed wing 31 is 46 to 56 pieces, and a preferred range of an angle between each stator blade 311 and a corresponding horizontal plane is 28 degrees to 33 degrees. A preferred range of the number of stator blades 311 included in the fourth-layer fixed wing 31 is 45 to 53, and a preferred range of an angle between each stator blade 311 and a corresponding horizontal plane is 27 degrees to 32 degrees. A preferred range of the number of stator blades 311 included in the fifth-layer fixed wing 31 is 38 to 46, and a preferred range of the angle between each stator blade 311 and a corresponding horizontal plane is 15 degrees to 21 degrees. A preferred range of the number of stator blades 311 included in the sixth-layer fixed wing 31 is 38 to 46, and a preferred range of an angle between each stator blade 311 and a corresponding horizontal plane is 13 to 18 degrees. A preferred range of the number of stator blades 311 included in the seventh-layer fixed wing 31 is 38 to 46, and a preferred range of the angle between each stator blade 311 and a corresponding horizontal plane is 13 to 18 degrees.

Please refer to FIG. 3 and FIG. 4. The inventor found that the rotor element 2 rotating at high speed in a high-temperature environment is prone to form fatigue fracture points on the second seat 212 of the rotor seat 21; therefore, the second seat A reinforcement structure 4 is provided at a specific position of the body 212, which can resist high temperature effects for a long time without affecting all high-speed dynamic characteristics and evacuation efficiency of the rotor element 2. Further, the second base 212 has a front end portion 2121 and a rear end portion 2122 extending from a distal end of the front end portion 2121. The rear end portion 2122 is closer to the exhaust port 13 than the front end portion 2121, and the rear end portion 2122 The thickness is smaller than the thickness of the front end portion 2121, and the reinforcing structure 4 is disposed around the rear end portion 2122.

In this embodiment, the thickness of the front end portion 2121 is h, and the thickness of the rear end portion 2122 is greater than 2 / 3h but less than h; wherein the rear end portion 2122 is formed by removing a part of the outer diameter material by machining, but not Limited to this. Reinforcement structure 4 is a ring structure, and can be put on the rear end 2122 in an ultra-low temperature environment near minus 200 ° C, but not Limited to this; preferably, the front end portion 2121 has an inner peripheral wall W22 and an outer peripheral wall W23 opposite to each other, wherein the inner peripheral wall W22 is closer to the high-speed spindle 23 than the outer peripheral wall W23, and the outer surface of the reinforcement structure 4 and the outer peripheral wall W23 Level.

The material of the reinforcing structure 4 is titanium alloy or carbon fiber, but it is not limited thereto. It is worth noting that although titanium alloy is 1.6 times heavier than aluminum alloy, the tensile strength of titanium alloy is close to that of special steel, which is twice that of aluminum alloy, and titanium alloy has more excellent corrosion resistance and heat resistance; carbon fiber (also (Called graphite fiber) is a high-strength, high-modulus high-end fiber, and has the characteristics of light weight, high hardness, high chemical resistance, high temperature resistance and low thermal expansion. In other embodiments, the material of the reinforcing structure 4 may be stainless steel, low alloy steel, or heat resisting alloy, or other fiber materials, such as glass fiber. ), Kevlar fiber, boron fiber, silicon carbide fiber, etc.

The power base 5 has a bearing mechanism 51 disposed between the rotor base 21 and the high-speed main shaft 23 to drive the rotor base 21 together with the rotary wing 22 to rotate at a high speed through the high-speed main shaft 23 to promote the flow of gas molecules from the air inlet 12 to the exhaust气 口 13. The gas port 13. In this embodiment, the bearing mechanism 51 is an electromagnetic bearing, which includes a motor, an electromagnet group (not labeled), and the like distributed along the axial direction; the bearing mechanism 51 can generate magnetic force to support the rotor element 2 so that the rotor element 2Floats in the axial direction and maintains a stable and suspended equilibrium position. The structure of the bearing mechanism 51 is well known to those skilled in the art, so it will not be described in detail here.

Please refer to FIG. 1 to FIG. 3. The turbo molecular pump P may further include a heating device 6 disposed around the power base 5 as needed. For example, when the turbomolecular pump P can be applied to an etching device to slow down the formation of deposits and thereby extend the interval of preventive maintenance (PM).

[Second embodiment]

Please refer to FIG. 8, and please refer to FIG. 3. This embodiment of the turbo molecular pump The structural composition of P is substantially the same as that described in the first embodiment. The main difference is that the reinforcing structure 4 is a composite structure.

In this embodiment, the reinforcing structure 4 includes a first strengthening layer 41 and a second strengthening layer 42 formed on the first strengthening layer 41, wherein the material of the first strengthening layer 41 is a titanium alloy and the second strengthening layer 42 The material is carbon fiber, but it is not limited to this. In other embodiments, the material of the first reinforcing layer 41 may be stainless steel, low-alloy steel, or heat-resistant alloy, and the material of the second reinforcing layer 42 may be glass fiber, Kevlar fiber, boron fiber, or silicon carbide fiber. The reinforcing structure 4 may also be formed by alternately stacking a plurality of first reinforcing layers 41 and a plurality of second reinforcing layers 42.

[Third embodiment]

Please refer to FIG. 9, the structural composition of the turbo molecular pump P in this embodiment is substantially the same as that described in the first embodiment. The main difference is that the rear end portion 2122 of the second seat body 212 of the rotor seat 21 is not completely reinforced. Structure 4 is covered. In this embodiment, the reinforcing structure 4 is spirally wound around the outer peripheral wall of the rear end portion 2122 in the axial direction, but is not limited thereto. The reinforcing structure 4 may be a discontinuous structure, that is, formed on the outer peripheral wall of the rear end portion 2122 in a dispersed manner.

[Advantageous Effects of the Embodiment]

One of the beneficial effects of the present invention lies in the technical solution of the turbo molecular pump provided by the present invention, which can be provided on the rotor seat through a reinforcing structure and avoids the coverage area of multiple rotating wings and multiple fixed wings. In order not to affect all the high-speed dynamic characteristics and evacuation efficiency of the rotor element, to avoid the fatigue point of the rotor element from fatigue fracture in high temperature environment, and then effectively extend the operating life of the pump.

Furthermore, the turbo molecular pump provided by the present invention can reduce the generation of sediments by heating, and can resist the high temperature working environment.

The content disclosed above is only the preferred and feasible embodiment of the present invention, and thus does not limit the scope of patent application of the present invention. Therefore, whenever the description and drawings of the present invention are used, The equivalent technical changes made by the content are all included in the scope of patent application of the present invention.

Claims (11)

A turbomolecular pump includes: a casing having a cavity; a stator element disposed in the cavity, wherein the stator element includes a plurality of fixed wings; a rotor element, The rotor element is disposed in the cavity and has a degree of freedom of rotation relative to the stator element, wherein the rotor element includes a rotor base and a plurality of rotary wings connected to the rotor base, and The rotating wing is alternately arranged with a plurality of the fixed wings; and a reinforcing structure is disposed on the rotor base and avoids a covered area of the plurality of rotating wings and the plurality of fixed wings; The reinforcement structure includes at least one first reinforcement layer and at least one second reinforcement layer stacked together. At least one of the first reinforcement layers is made of stainless steel, low alloy steel, or heat resistant alloy, and at least one of the The material of the second reinforcing layer is glass fiber, boron fiber or silicon carbide fiber. The turbomolecular pump according to claim 1, wherein two ends of the casing have an air inlet and an air outlet connected to the cavity, respectively, and the rotor seat includes a first seat body and A second base body extending from the end of the first base body, the first base body is adjacent to the air inlet, the second base body is adjacent to the exhaust outlet, and the first base body is An outer diameter of a base body is smaller than an outer diameter of the second base body, wherein a plurality of the rotary wings are connected to the first base body. The turbo molecular pump according to claim 2, wherein the reinforcing structure is provided on the second base. The turbomolecular pump according to claim 3, wherein the second base body has a front end portion and a rear end portion extending from a distal end of the front end portion, and the rear end portion is longer than the front end portion. It is closer to the exhaust port, and the thickness of the rear end portion is smaller than the thickness of the front end portion, wherein the reinforcement structure is provided around the rear end portion. The turbomolecular pump according to claim 4, wherein the thickness of the front end portion is h, and the thickness of the rear end portion is greater than 2 / 3h but less than h. The turbomolecular pump according to claim 4, wherein the rotor element further includes a high-speed spindle, and the high-speed spindle is disposed in the rotor seat, wherein the front end portion has an inner peripheral wall and an opposite The outer peripheral wall of the inner peripheral wall is closer to the high speed spindle than the outer peripheral wall, wherein the reinforcing structure has an outer surface, and the outer surface is flush with the outer peripheral wall. The turbomolecular pump according to claim 4, wherein the reinforcing structure is a ring structure. The turbo molecular pump according to claim 6, further comprising a power base for assembling the housing, the stator element, and the rotor element, wherein the power base has a bearing mechanism, so The bearing mechanism is disposed between the rotor base and the high-speed spindle, and is used to drive the rotor element through the high-speed spindle. The turbo molecular pump according to claim 6, further comprising a heating device, and the heating device is arranged around the power base. The turbomolecular pump according to claim 1, wherein the cavity is a vacuum cavity. The turbomolecular pump according to claim 1, wherein each of the fixed wings includes a plurality of stator blades, and each of the rotary wings includes a plurality of rotor blades.