Rotor structure of high-cleanliness molecular pump suitable for EUV photoetching machine

Abstract

The utility model provides a rotor structure of a high-cleanliness molecular pump suitable for an EUV photoetching machine. The rotor structure comprises a turbine rotor, a turbine structure located on the upper portion and arranged outside the turbine rotor, and a fourth traction wheel arranged inside the turbine rotor and used as a secondary traction wheel compression mechanism. The traction wheel rotor is located on the lower portion and serves as a first-stage traction wheel compression mechanism; and the vortex blade row is located on the lower portion and arranged on the inner side of the traction wheel rotor, an air channel inlet in the top of the turbine structure serves as an air inlet end, the turbine structure, the first-stage traction wheel compression mechanism, the vortex blade row and the fourth traction wheel are sequentially arranged from upstream to downstream, and an air channel outlet of the fourth traction wheel communicates with a main shaft assembling area in the rotor assembly. The secondary traction wheel is arranged on the inner side of the rotor, higher impulse is given to pollutants through high-speed rotation of the spiral, the pollutants are effectively discharged, the reverse flow probability of the pollutants is greatly reduced, and the problem that the pollutants are difficult to effectively discharge only through the traction effect under the condition that the traction wheel is arranged on the stator is solved.

Description

TECHNICAL FIELD

[0001] The utility model relates to molecular pump technical field, specifically, it relates to a rotor structure of high cleanness molecular pump suitable for EUV photoetching machine, especially a rotor structure of high cleanness magnetic suspension bearing type composite molecular pump with super high compression ratio and large pumping speed suitable for EUV photoetching machine. BACKGROUND

[0002] With the integrated circuit process to 5 nanometer and below more advanced process, in EUV (extreme ultraviolet) photoetching process, since EUV is extremely easy to attenuate in atmosphere (more than 99% attenuation in a few millimeters distance), and requires super high cleanness. Therefore, only large pumping speed, super high compression ratio (vacuum degree 10 －7 Pa level start), super clean vacuum system can make it work normally.

[0003] Firstly, large pumping speed, which is the natural strong point of the turbine molecular pump, there is no problem and obstacle in this regard at present;

[0004] Secondly, super high compression ratio, the patent (publication number CN120140176B) of the applicant's prior application: composite multi-compression mechanism vacuum pump with high compression ratio and large pumping speed improves the compression ratio through the compression mechanism of "turbine + traction wheel + scroll blade row", which has met the compression ratio requirement;

[0005] Thirdly, super high cleanness, EUV photoetching machine is extremely sensitive to tin droplet gasification and related products, hydrocarbon contaminants (mainly photoresist and material outgassing), and particle contaminants (various mechanical wear and tear debris and inhaled various particle contaminants, mainly the impact wear and tear debris of the protective bearing in the magnetic suspension turbine molecular pump). However, the molecular pump used in the EUV photoetching machine at present still adopts the rotor of the traditional structure of "turbine + one-stage traction wheel", and the number of stages of the turbine may be increased, but both the compression ratio and the cleanness level need to be improved. Even if a small amount of molecular pumps adopt the structure of configuring a traction wheel on the stator, it is difficult to effectively discharge the contaminants by traction alone, and it still cannot meet the requirement of super high cleanness;

[0006] In view of the above situation and requirement, the technical field urgently needs an optimized molecular pump rotor structure, so that the molecular pump has super high cleanness while meeting the requirement of super high compression ratio. UTILITY MODEL CONTENTS

[0007] In view of the defects in the prior art, the purpose of the utility model is to provide a rotor structure of high cleanness molecular pump suitable for EUV photoetching machine.

[0008] According to the rotor structure of high cleanness molecular pump suitable for EUV photoetching machine provided by the utility model, the rotor structure comprises a rotor assembly, and the rotor assembly comprises:

[0009] a turbine rotor, located at the upper part of the rotor assembly, and provided with a turbine structure outside the turbine rotor for forming a turbine compression mechanism, and provided with a third traction wheel and a fourth traction wheel inside the turbine rotor as a secondary traction wheel compression mechanism;

[0010] a traction wheel rotor, located at the lower part of the rotor assembly, as a primary traction wheel compression mechanism;

[0011] a scroll blade row, located at the lower part of the rotor assembly and arranged inside the traction wheel rotor, for forming a scroll compression mechanism;

[0012] the gas passage inlet at the top of the turbine structure is the gas inlet end of the rotor assembly, the gas passage outlet at the bottom of the turbine structure is connected to the gas passage inlet of the primary traction wheel compression mechanism, the gas passage outlet of the primary traction wheel compression mechanism is connected to the gas passage inlet of the scroll blade row;

[0013] the gas passage outlet of the scroll blade row is connected to the third traction wheel and the fourth traction wheel, and the gas passage outlet at the top of the fourth traction wheel is connected to the gas passage outlet at the bottom of the third traction wheel, respectively.

[0014] Preferably, the gas passage outlet at the top of the fourth traction wheel is arranged separately from the main shaft assembly surface of the rotor assembly.

[0015] Preferably, the outer part and the inner part of the traction wheel rotor are respectively provided with a first traction wheel and a second traction wheel with opposite rotation directions, wherein the rotation direction of the second traction wheel is the same as that of the fourth traction wheel.

[0016] the gas passage outlet at the bottom of the turbine structure is connected to the gas passage inlet at the top of the first traction wheel, the gas passage outlet at the bottom of the first traction wheel is connected to the gas passage inlet at the bottom of the second traction wheel, and the gas passage outlet at the top of the second traction wheel is connected to the gas passage inlet of the scroll blade row.

[0017] Preferably, the bottom of the turbine rotor extends downward to form an extension, and the inner side of the extension is provided with a third traction wheel with opposite rotation direction to the fourth traction wheel.

[0018] the third traction wheel and the fourth traction wheel together form a secondary traction wheel compression mechanism, the gas passage inlet at the top of the third traction wheel is connected to the gas passage outlet of the scroll blade row, and the gas passage outlet at the bottom of the third traction wheel is connected to the main shaft assembly area inside the rotor assembly.

[0019] Preferably, the inner side wall at the junction of the turbine rotor and the extension is provided with a gas hole connected to the scroll blade row as the gas passage outlet of the scroll blade row.

[0020] Preferably, the turbine structure comprises a plurality of turbine blades arranged in layers.

[0021] Preferably, the bottom of the turbine rotor extends radially outward to form a stepped structure, the outer edge of the stepped structure extends downward to form a traction wheel rotor, and the scroll blade row is arranged annularly in the lower middle part of the turbine rotor.

[0022] Preferably, the middle part of the traction wheel rotor is provided with a vertical cylindrical partition, and the outer side and the inner side of the vertical cylindrical partition are both processed with a spiral structure to form a first traction wheel and a second traction wheel, respectively.

[0023] The gas path inlet of the first traction wheel is directly communicated with the gas path outlet of the turbine compression mechanism, and the gas path outlet of the first traction wheel is communicated with the gas path inlet of the second traction wheel through the gap between the vertical cylindrical partition and the shell assembly.

[0024] Compared with the prior art, the utility model has the beneficial effects that:

[0025] The utility model discloses a two-stage traction wheel compression mechanism is additionally configured downstream of the scroll blade row compression mechanism, and by setting the two-stage traction wheel compression mechanism on the inner side of the rotor (not on the stator), the high-speed rotation of the spiral is used to give various pollutants higher impulse, effectively discharges them, greatly reduces the probability of backflow into the cavity, solves the problem that in the case of setting the traction wheel on the stator, it is difficult to effectively discharge the pollutants only by traction, and very fits the vacuum degree and cleanliness requirement of more advanced processes of 5 nanometers and below. BRIEF DESCRIPTION OF DRAWINGS

[0026] Other features, objects and advantages of the utility model will become more apparent through reading the following detailed description of the non-limiting embodiments with reference to the accompanying drawings:

[0027] Figure 1 It is the whole structure schematic diagram of the utility model;

[0028] Figure 2 It is the structure schematic diagram of the compound molecular pump in the embodiment of the utility model.

[0029] The drawings show that:

[0030] DETAILED DESCRIPTION

[0031] The utility model will be described in detail below in combination with specific embodiments. The following embodiments will help the person skilled in the art to further understand the utility model, but do not limit the utility model in any form. It should be pointed out that, for ordinary skilled in the art, on the premise of not departing from the concept of the utility model, a number of changes and improvements can be made. These all belong to the protection scope of the utility model.

[0032] This invention discloses a rotor structure for a high-cleanliness molecular pump suitable for EUV lithography machines. By additionally configuring a secondary traction wheel compression mechanism downstream of the vortex blade compression mechanism, compared with the conventional solution of installing traction wheels on the stator, the high-speed rotation of the spiral gives various contaminants higher momentum, effectively discharging them and greatly reducing the probability of them flowing back into the cavity. This solves the problem that when traction wheels are installed on the stator, it is difficult to effectively discharge contaminants by traction alone. This is very suitable for the vacuum and cleanliness requirements of 5 nanometers and below more advanced processes.

[0033] Based on the rotor structure of the high-cleanliness molecular pump suitable for EUV lithography machines described above, an embodiment of this utility model also discloses a high-cleanliness composite molecular pump suitable for EUV lithography machines, such as... Figure 2 As shown, it includes a housing assembly, a motor 10, a stator assembly, a rotor assembly (i.e., the rotor structure of the high-cleanliness molecular pump suitable for EUV lithography machines provided by this utility model), and a main shaft 38; the stator assembly is fixedly installed inside the housing assembly, the main shaft 38 is rotatably installed in the shaft hole inside the stator assembly, the rotor assembly is installed inside the housing assembly and is coaxially fixedly connected to the main shaft 38, and the motor 10 is installed on the stator assembly to drive the main shaft 38 to rotate;

[0034] like Figure 1 As shown, the rotor assembly is equipped with a turbine compressor, a first-stage traction wheel compressor, a vortex blade compressor, and a second-stage traction wheel compressor, which are arranged sequentially from upstream to downstream. The second-stage traction wheel compressor is located on the inner wall of the rotor assembly and includes a third traction wheel and a fourth traction wheel. The direct air passage outlet of the third traction wheel is directly connected to the second-stage exhaust port. The air passage outlet of the fourth traction wheel is connected to the top of the shaft hole where the main shaft is located, and is connected to the second-stage exhaust port of the housing assembly through the bottom of the shaft hole. During air extraction, the gas passes through the turbine compressor, the first-stage traction wheel compressor, the vortex blade compressor, and the second-stage traction wheel compressor in sequence, and is finally discharged from the second-stage exhaust port.

[0035] The utility model discloses a two-stage traction wheel compression mechanism is additionally arranged on the inside wall of rotor assembly, utilizes the high -speed operation of spiral to give various pollutants higher momentum, effectively discharges it, can greatly reduce its reflux into the cavity's probability, in addition to the matching use innovation of compression mechanism, also has improved on the design of gas path, specifically, the conventional molecular pump is to the shaft hole of main shaft 38 is from the blow -down cleaning of up, and the application will be the gas path improvement is from the top of shaft hole, after passing through the shaft hole from top to bottom, again from two -stage exhaust port 15 discharge. The purpose of doing this is to prevent the pollution in the pump body or gas reflux, but will take the pollution in the cavity and enter the shaft hole ( part passes two -stage exhaust port and discharges), in other words, through the strategy of " give up the car and protect the general", the risk of pollution reflux is transferred to the shaft hole, thereby improve the cleanliness of the photolithography machine, in order to improve yield, and the above scheme is very wise and reasonable.

[0036] In one preferred embodiment, as shown in Figure 1 The rotor assembly comprises:

[0037] A turbine rotor 7 is located at the upper part of the rotor assembly, and a turbine structure outside the turbine rotor 7 forms a turbine compression mechanism with the fixed piece of the inner wall of the shell assembly. The inside of the turbine rotor 7 is provided with a fourth traction wheel 31 as a two-stage traction wheel compression mechanism.

[0038] A traction wheel rotor is located at the lower part of the rotor assembly as a first-stage traction wheel compression mechanism.

[0039] A scroll blade row 9 is located at the internal step of the rotor assembly and is arranged inside the traction wheel rotor, and forms a scroll compression mechanism with the scroll guide groove of the shell assembly.

[0040] The gas path inlet of the turbine compression mechanism is communicated with the gas inlet 40 at the top of the shell assembly, the gas path outlet of the turbine compression mechanism is communicated with the gas path inlet of the first-stage traction wheel compression mechanism, the gas path outlet of the first-stage traction wheel compression mechanism is communicated with the gas path inlet of the scroll compression mechanism; the gas path outlet of the scroll compression mechanism is simultaneously communicated with the gas path inlets of the third traction wheel 26 and the fourth traction wheel 31, the gas path outlet of the third traction wheel 26 is directly communicated with the two-stage exhaust port 15, and the gas path outlet of the fourth traction wheel 31 is communicated with the top of the shaft hole where the main shaft 38 is located, and is communicated with the two-stage exhaust port 15 at the bottom of the shaft hole after passing through the shaft hole.

[0041] In further preferred examples, the outer part and the inner part of the traction wheel rotor are respectively provided with first traction wheel 11 and second traction wheel 12 of opposite rotation directions, wherein the rotation direction of the second traction wheel 12 is the same as that of the fourth traction wheel 31; the exhaust port comprises a primary exhaust port 24 and a secondary exhaust port 15, the gas path outlet at the bottom of the turbo compressor mechanism is communicated with the gas path inlet at the top of the first traction wheel 11, the gas path outlet at the bottom of the first traction wheel 11 is simultaneously communicated with the primary exhaust port 24 and the gas path inlet at the bottom of the second traction wheel 12; the gas path outlet at the top of the second traction wheel 12 is communicated with the gas path inlet of the scroll compressor mechanism, the gas path outlet of the scroll compressor mechanism is simultaneously communicated with the gas path inlet at the bottom of the third traction wheel 26 and the fourth traction wheel 31, the gas path outlet of the third traction wheel 26 is directly communicated with the secondary exhaust port 15, and the gas path outlet of the fourth traction wheel 31 is communicated with the top of the shaft hole where the main shaft 38 is located, and after passing through the shaft hole, it is communicated with the secondary exhaust port 15 at the bottom of the shaft hole.

[0042] Specifically, the middle part of the traction wheel rotor is provided with a vertical cylindrical partition, and the first traction wheel 11 and the second traction wheel 12 are respectively arranged on the outer side and the inner side of the vertical cylindrical partition; the gas path inlet of the first traction wheel 11 is directly communicated with the gas path outlet of the turbo compressor mechanism, and the gas path outlet of the first traction wheel 11 is communicated with the gas path inlet of the second traction wheel 12 through the gap between the vertical cylindrical partition and the shell assembly.

[0043] The valve 25 is installed on the primary exhaust port 24, when pre-pumping, the valve 25 is opened, a part of the gas passes through the turbo compressor mechanism and the first traction wheel 11 in turn, and is discharged from the primary exhaust port 24, and the other part continues to pass through the second traction wheel 12, the scroll compressor mechanism, and the third traction wheel 26 and the fourth traction wheel 31, and is finally discharged from the secondary exhaust port 15 (the gas path outlet of the third traction wheel 26 is directly communicated with the secondary exhaust port 15; the gas path outlet of the fourth traction wheel 31 is communicated with the shaft hole where the main shaft 38 is located, and the bottom of the shaft hole is communicated with the secondary exhaust port 15, so the gas compressed by the third traction wheel 26 and the fourth traction wheel 31 is finally discharged from the secondary exhaust port); after pre-pumping is completed, when in the second pumping stage, the valve 25 is closed, the remaining gas passes through the turbo compressor mechanism, the first traction wheel 11, the second traction wheel 12, the scroll compressor mechanism, and the third traction wheel 26 and the fourth traction wheel 31 in turn, and is finally discharged from the secondary exhaust port 15 (the gas path outlet of the third traction wheel 26 is directly communicated with the secondary exhaust port 15; the gas path outlet of the fourth traction wheel 31 is communicated with the shaft hole where the main shaft 38 is located, and the bottom of the shaft hole is communicated with the secondary exhaust port 15, so the gas compressed by the third traction wheel 26 and the fourth traction wheel 31 is finally discharged from the secondary exhaust port);

[0044] In this embodiment, the primary exhaust port 24 and the valve 25 are used to improve the pre-extraction efficiency. After the pre-extraction is completed, the gas is finally discharged through the secondary exhaust port 15. The specific working principle of this mechanism can refer to the prior patent of the applicant (publication number CN120140176B), which will not be repeated here.

[0045] In a preferred embodiment, the shell assembly includes an outer cylinder 1, a base 16, a sealing cover 17, and a stator assembly. The outer cylinder 1 is installed on the base 16, the main shaft 38 is rotatably installed in the middle of the base 16, the rotor assembly is rotatably installed in the outer cylinder 1, the stator assembly is fixedly installed on the base 16, and the sealing cover 17 is installed at the bottom of the base 16 to seal the shaft hole. The lower side of the scroll blade row 9 has a scroll guide groove, which forms a scroll compression mechanism with the scroll blade row 9 on the lower side of the rotor assembly. The primary traction wheel compression mechanism is arranged on the inner and outer sides of the cylindrical partition at the lower part of the turbine rotor. There is a gap between the top of the stator assembly and the rotor assembly. The gas path outlet of the fourth traction wheel 31 in the secondary traction wheel compression mechanism communicates with the top of the shaft hole through the gap. The stator assembly is in close proximity to the fourth traction wheel 31, forming a gas path for the fourth traction wheel 31. There is a gap between the top of the stator assembly and the main shaft assembly surface of the rotor assembly. There is a protective gap between the upper journal of the main shaft 38 and the second protective bearing 37. There is also a large gap between the rolling balls of the second protective bearing 37. These gaps and spaces can be used as communication channels for the gas path outlet of the fourth traction wheel 31 and the shaft hole. Through the above improvements, the exhaust path can be improved to be along the shaft hole from top to bottom.

[0046] In a preferred embodiment, the bottom of the scroll blade row 9 extends downward to form an extension, and the inner side of the extension is provided with a third traction wheel 26 that rotates in the opposite direction of the fourth traction wheel 31. The third traction wheel 26 and the fourth traction wheel 31 together serve as the secondary traction wheel compression mechanism. The gas path inlet at the top of the third traction wheel 26 communicates with the gas path outlet of the scroll compression mechanism, and the gas path outlet at the bottom of the third traction wheel 26 directly communicates with the secondary exhaust port 15 of the pump body assembly. The working principle is as follows: the extracted gas and pollutants enter from the gas inlet 40, pass through the turbine rotor 7 (turbine compression mechanism), the first traction wheel 11, the second traction wheel 12, and the scroll blade row 9 in sequence, and are compressed by the scroll blade row 9. After being discharged from the scroll blade row 9, the gas and pollutants are divided into two paths: one part of the gas and pollutants is compressed by the third traction wheel 26 and finally discharged through the secondary exhaust port 15; the remaining part of the gas and pollutants is compressed by the fourth traction wheel 31 and enters the shaft hole where the main shaft 38 is located, and is finally discharged through the secondary exhaust port 15 at the bottom of the shaft hole.

[0047] The utility model discloses a fourth traction wheel 31 is additionally arranged, gas and pollutant can be compressed from the top of axle hole to the bottom of axle hole, thereby discharging through two -stage exhaust port 15, specifically, the path of " from below to top " in conventional scheme needs external ventilation, in some corrosive process, in order to prevent corrosive gas from entering axle hole and corroding parts, need external gas to drive corrosive gas out of axle hole, or at least can dilute the concentration of corrosive gas, reduce its corrosion effect, finally the gas and the gas of passing in are discharged from the exhaust port (this condition has only one exhaust port).The utility model discloses application in EUV photoetching machine, because there is no corrosive gas in EUV photoetching machine, only ordinary pollutant, therefore can enter axle hole. In order to improve the cleanliness of photoetching machine, the utility model discloses through " from top to bottom " compression path and keep pollutant mainly in axle hole ( relative to the conventional molecular pump pollutant kept in base), thereby guaranteeing super high cleanliness, the utility model discloses through concrete problem concrete analysis, and the super high cleanliness scheme of special molecular pump for EUV photoetching machine is proposed.

[0048] In addition, the utility model additionally sets up third traction wheel 26, gas and pollutant are discharged after being compressed from vortex blade row mechanism, especially pollutant, if not setting up third traction wheel 26, then will be easy to adhere to the position of third traction wheel 26, still have a certain probability to enter cavity, the utility model discloses through setting up third traction wheel 26, gas and pollutant can only be pushed downstream, until two -stage exhaust port 15, further improve cleanliness.

[0049] The turbine structure comprises a plurality of turbine blades arranged in layers; a plurality of fixed plates arranged in layers are fixedly installed in the interior of the stator assembly by a compression ring, the fixed plates and the turbine blades are alternately installed in sequence to form a turbine compression mechanism. In one preferred example, the inner side wall of the outer cylinder 1 is sequentially provided with a first fixed plate 27, a second fixed plate 28, a third fixed plate 29, a fourth fixed plate 30, a fifth fixed plate 33, a sixth fixed plate 35, a seventh fixed plate 36 and an eighth fixed plate 39 from bottom to top, and the above fixed plates are fixed in the interior of the outer cylinder 1 by a first compression ring 2, a second compression ring 3, a third compression ring 4, a fourth compression ring 5, a fifth compression ring 6, a sixth compression ring 8 and a seventh compression ring 23 located in the gap. It should be noted that the number of turbine compression stages is not fixed, but is set according to actual needs.

[0050] In a preferred example, the axial unit 18, the axial sensor 19, the target head 20 and the thrust disc 21 are further included; the axial unit 18 is installed between the base 16 and the bottom of the main shaft 38, the thrust disc 21, the target head 20 and the axial sensor 19 are coaxially installed from top to bottom at the bottom end of the main shaft 38, and are all located inside the axial unit 18; the axial unit 18, the axial sensor 19, the target head 20 and the thrust disc 21 form an axial magnetic suspension bearing. The first radial coil 13 and the first radial sensor 14 are arranged between the lower part of the main shaft 38 and the base 16, and the second radial coil 32 and the second radial sensor 34 are arranged between the upper part of the main shaft 38 and the stator assembly. Among them, the first protection bearing 22 and the second protection bearing 37 are arranged outside the main shaft 38; the first protection bearing 22 is arranged between the main shaft 38 and the axial unit 18, and the second protection bearing 37 is arranged between the main shaft 38 and the stator assembly, preferably, the first protection bearing 22 and the second protection bearing 37 are low-dust protection bearings, which can reduce the dust amount in the bearing impact wear process as much as possible, which is one of the important measures to improve cleanliness.

[0051] The utility model not only combines and upgrades the compression mechanism as "turbine + first level traction wheel + scroll blade + second level traction wheel", but also makes more reasonable design for the special situation of EUV photoetching machine, compared with the existing EUV photoetching machine molecular pump, through adopting scroll blade compression structure and increasing traction compression structure scheme, the exhaust path is improved, the compression ratio and cleanliness can be greatly improved under the condition of keeping the pumping speed unchanged, and the problem of high requirement of vacuum degree and cleanliness of the current EUV photoetching machine special molecular pump is solved synchronously.

[0052] In the description of the present application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore cannot be understood as a limitation on the present application.

[0053] The specific embodiments of the utility model have been described above. It should be understood that the utility model is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essential content of the utility model. In the case of no conflict, the embodiments of the present application and the features in the embodiments can be combined with each other at will.

Claims

1. A rotor structure for a high cleanliness molecular pump suitable for use in an EUV lithography machine, characterized in that, The rotor assembly comprises: A turbine rotor (7) is located at the upper part of the rotor assembly, and a turbine structure is arranged outside the turbine rotor (7) to form a turbine compression mechanism. The inner side of the turbine rotor (7) is provided with a third traction wheel (26) and a fourth traction wheel (31) as a two-stage traction wheel compression mechanism. A traction wheel rotor is located at the lower part of the rotor assembly as a one-stage traction wheel compression mechanism. A scroll blade row (9) is located at the middle-lower part of the rotor assembly and is arranged in a ring shape inside the traction wheel rotor to form a scroll compression mechanism. The gas path inlet at the top of the turbine structure is the gas inlet end of the rotor assembly, the gas path outlet at the bottom of the turbine structure is connected to the gas path inlet of the one-stage traction wheel compression mechanism, the gas path outlet of the one-stage traction wheel compression mechanism is connected to the gas path inlet of the scroll blade row (9). The gas path outlet of the scroll blade row (9) is connected to the third traction wheel (26) and the fourth traction wheel (31), and the gas path outlet at the top of the fourth traction wheel (31) is connected to the gas path outlet at the bottom of the third traction wheel (26).

2. The rotor structure for a high cleanliness molecular pump suitable for use in an EUV lithography machine according to claim 1, characterized in that, The gas path outlet at the top of the fourth traction wheel (31) is spaced apart from the main shaft assembly surface of the rotor assembly.

3. The rotor structure for a high cleanliness molecular pump suitable for use in an EUV lithography machine according to claim 1, characterized in that, The outer side and the inner side of the traction wheel rotor are respectively provided with a first traction wheel (11) and a second traction wheel (12) with opposite rotation directions, wherein the rotation direction of the second traction wheel (12) is the same as that of the fourth traction wheel (31). The gas path outlet at the bottom of the turbine structure is connected to the gas path inlet at the top of the first traction wheel (11), the gas path outlet at the bottom of the first traction wheel (11) is connected to the gas path inlet at the bottom of the second traction wheel (12), and the gas path outlet at the top of the second traction wheel (12) is connected to the gas path inlet of the scroll blade row (9).

4. The rotor structure for a high cleanliness molecular pump suitable for use in an EUV lithography machine according to claim 1, characterized in that, The bottom of the scroll blade row (9) extends downward to form an extension, and the inner side of the extension is provided with a third traction wheel (26) with a rotation direction opposite to that of the fourth traction wheel (31). The third traction wheel (26) and the fourth traction wheel (31) together form a two-stage traction wheel compression mechanism, the gas path inlet at the top of the third traction wheel (26) is connected to the gas path outlet of the scroll blade row (9), and the gas path outlet at the bottom of the third traction wheel (26) is directly connected to the two-stage exhaust port (15).

5. A rotor structure for a high cleanliness molecular pump suitable for use in an EUV lithography machine according to claim 4, characterized in that, A gas hole is arranged on the inner side wall at the junction of the scroll blade row (9) and the extension, which is connected to the scroll blade row (9) and is also connected to the gas path inlets of the third traction wheel (26) and the fourth traction wheel (31).

6. The rotor structure for a high cleanliness molecular pump suitable for use in an EUV lithography machine according to claim 1, characterized in that, The turbine structure comprises a plurality of turbine blades arranged in layers.

7. The rotor structure for a high cleanliness molecular pump suitable for use in an EUV lithography machine according to claim 1, characterized in that, The bottom of the turbine rotor (7) extends radially outward to form a stepped structure, the outer edge of the stepped structure extends downward to form a traction wheel rotor, and the scroll blade row (9) is arranged in a ring shape at the middle-lower part of the central part of the turbine rotor.

8. The rotor structure of a high-purity molecular pump suitable for use in an EUV lithography machine according to claim 3, characterized in that, A vertical cylindrical partition is arranged in the middle part of the traction wheel rotor, and the outer side and the inner side of the vertical cylindrical partition are both provided with a spiral structure to form the first traction wheel (11) and the second traction wheel (12), respectively. The air path inlet of the first traction wheel (11) is directly communicated with the air path outlet of the turbo compressor mechanism, and the air path outlet of the first traction wheel (11) is communicated with the air path inlet of the second traction wheel (12) through the gap between the vertical cylindrical partition plate and the pump body assembly.

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