Low-temperature vacuum pump with good stability

Abstract

The utility model relates to the technical field of vacuum equipment, in particular to a low-temperature vacuum pump with good stability, which comprises an outer shell, a multi-stage cold shield structure, a multi-stage adsorption array structure, a multi-stage cold head and a regeneration mechanism, the multi-stage cold shield structure and the multi-stage adsorption array structure are arranged, so that a required vacuum environment can be quickly realized, the stability of a vacuum state is ensured, and a high-cleanliness vacuum environment is provided for semiconductor processing; by arranging the multi-stage cold screen structure, the influence of environmental heat radiation on structural condensation and gas adsorption of the adsorption array structure can be reduced, and the stability of a vacuum state is ensured; the multi-stage adsorption array structure is arranged to perform multi-stage adsorption on gas molecules, so that the effective contact area of gas can be increased, namely, the condensation or adsorption area of the gas is increased, the influence of direct radiant heat of the vacuum chamber on the vacuum state is reduced, and the required high vacuum state is quickly realized; the regeneration mechanism can provide rapid regeneration for the low-temperature vacuum pump, the working efficiency is improved, and operation is more convenient.

Description

Technical Field

[0001] The utility model relates to the technical field of vacuum equipment, and particularly relates to a cryogenic vacuum pump with good stability. Background Art

[0002] Due to its advantages such as high vacuum degree, high cleanliness, large gas capacity, and fast pumping speed, cryogenic vacuum pumps are gradually widely used in the research and production of semiconductors and integrated circuits. Especially in the process of semiconductor processing, high requirements for vacuum degree and dust-free environment are needed. However, at present, during the use of cryogenic vacuum pumps, the vacuum environment is unstable, and temperature or vacuum degree fluctuations are likely to occur due to the influence of external factors, affecting the processing accuracy; at the same time, impurities are likely to exist in the refrigeration gas, affecting the vacuum degree and stability. Therefore, the existing technology needs to be further improved. Summary of the Utility Model

[0003] The purpose of the utility model is to provide a cryogenic vacuum pump with good stability to solve the existing technical problems in the above background art.

[0004] To solve the above technical problems, the technical solution provided by the utility model is: a cryogenic vacuum pump with good stability is provided, which includes an outer shell, a multi-stage cold screen structure, a multi-stage adsorption array structure, multi-stage cold heads, and a regeneration mechanism. The multi-stage cold screen structure includes at least one group of cold screens and is arranged inside the outer shell. The multi-stage adsorption array structure is arranged inside the outer shell and is used for condensing or adsorbing gas at low temperature. The multi-stage adsorption array structure includes at least one group of adsorption arrays and adsorption materials are arranged on the outer surfaces thereof; the multi-stage cold heads include a first cold head and a second cold head. The first cold head is arranged at the end of the second cold head, and the free end of the second cold head is arranged inside the multi-stage adsorption array structure. Refrigeration gas flows in the first cold head and the second cold head, which is used for cooling the multi-stage cold screen structure and the multi-stage adsorption array structure; the end of the regeneration mechanism extends into the outer shell and is located at the end of the second cold head.

[0005] Based on the above technical solution, the regeneration mechanism is set as a resistance heating plate.

[0006] Based on the above technical solution, the first cold head includes a primary piston, the second cold head includes a secondary piston, a copper mesh is arranged inside the primary piston, and lead pellets are filled inside the secondary piston.

[0007] Based on the above technical solution, the multi-stage cold screen structure includes an outer cold screen and an inner cold screen. The outer cold screen is fixedly arranged on the inner side wall of the outer shell and is adapted in shape. The inner cold screen is arranged inside the outer cold screen. The inner cold screen includes a plurality of annular baffles which are uniformly arranged from top to bottom, and adsorption materials are arranged on the surfaces of the annular baffles.

[0008] Based on the above technical solution, the multi-stage adsorption array structure includes a baffle plate, an outer adsorption array, and an inner adsorption array. The baffle plate is fixedly arranged at the top of the outer cold shield. The outer adsorption array is arranged between the outer cold shield and the inner cold shield and is located below the baffle plate. The inner adsorption array is arranged inside the inner cold shield.

[0009] Based on the above technical solution, the baffle plate includes a plurality of symmetrically arranged inclined baffle plates and is fixedly arranged at the top of the inner side wall of the outer cold shield. The outer adsorption array includes a plurality of adsorption sheets and is evenly arranged along the circumferential direction of the outer cold shield. The inner adsorption array includes an outer shell plate and a support frame. The support frame is fixedly arranged inside the inner cold shield. The outer shell plate surrounds the outside of the support frame and is evenly provided with long strip holes on the outer shell plate.

[0010] Based on the above technical solution, the annular baffle plates are all inclined inward, and the adsorption sheets are arranged perpendicular to the annular baffle plates.

[0011] Based on the above technical solution, it further includes a cold head housing. The cold head housing is sleeved outside the first cold head and the second cold head, and a sealing component is arranged between the first cold head, the second cold head and the inner wall of the cold head housing.

[0012] Based on the above technical solution, the sealing component is a combined structure of a guide ring, a Gleit ring and a guide ring or a polytetrafluoroethylene impregnated carbon fiber sealing filler.

[0013] The beneficial effects produced by the technical solution provided by the present invention are as follows:

[0014] The present invention provides a cryogenic vacuum pump with good stability. By setting a multi-stage cold shield structure and a multi-stage adsorption array structure, the required vacuum environment can be quickly realized, and the stability of the vacuum state can be ensured, providing a highly clean vacuum environment for semiconductor processing; by setting a multi-stage cold shield structure, the influence of environmental thermal radiation on the condensation and adsorption of gases by the adsorption array structure can be reduced, ensuring the stability of the vacuum state; by setting a multi-stage adsorption array structure to perform multi-stage adsorption on gas molecules, the effective contact area of the gas can be increased, that is, the gas condensation or adsorption area can be increased, reducing the influence of the direct radiation heat of the vacuum chamber on the vacuum state, and quickly realizing the required high vacuum state; the regeneration mechanism can provide rapid regeneration for the cryogenic vacuum pump, improve the working efficiency, and the operation is more convenient. Description of the Drawings

[0015] Figure 1 is the overall structural schematic diagram of the present invention;

[0016] Figure 2 is the three-dimensional structural schematic diagram of the first cold head and the second cold head in the present invention;

[0017] Figure 3It is a schematic internal structure diagram of the first cold head and the second cold head in the present utility model;

[0018] Figure 4 It is a three-dimensional structure schematic diagram of the multi-stage cold screen and the multi-stage adsorption array structure in the present utility model;

[0019] Figure 5 It is a schematic internal structure diagram of the multi-stage cold screen and the multi-stage adsorption array structure in the present utility model;

[0020] Figure 6 It is a three-dimensional structure schematic diagram of the outer adsorption array and the inner cold screen in the present utility model;

[0021] Figure 7 It is a structure schematic diagram of the inner cold screen and the inner adsorption array in the present utility model;

[0022] Figure 8 It is a structure schematic diagram of the inner adsorption array in the present utility model;

[0023] Figure 9 It is a structure schematic diagram of one of the sealing components in the present utility model;

[0024] Figure 10 It is a structure schematic diagram of another sealing component in the present utility model; Detailed implementation manners

[0025] The present utility model will be further described below in conjunction with the accompanying drawings and embodiments:

[0026] In the present utility model, unless otherwise clearly specified and limited, terms such as "installation", "connection", "connection", "fixation", etc. shall be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be directly connected, or indirectly connected through an intermediate medium, and can be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific situations.

[0027] In the description of the present utility model, it should be understood that the orientation or positional relationship indicated by terms such as "left", "right", "front", "rear", "top", "bottom", etc. are all based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present utility model.

[0028] Such as Figures 1 to 10As shown in the figure, a cryogenic vacuum pump with good stability includes a housing 1, a multi-stage cold shield structure, a multi-stage adsorption array structure, a multi-stage cold head, and a regeneration mechanism. The multi-stage cold shield structure includes at least one group of cold shields and is arranged inside the housing 1. The multi-stage adsorption array structure is arranged inside the housing 1 and is used for condensing or adsorbing gas at low temperature. The multi-stage adsorption array structure includes at least one group of adsorption arrays, and adsorption materials are arranged on the outer surfaces thereof. The multi-stage cold head includes a first cold head 4 and a second cold head 5. The first cold head 4 is arranged at the end of the second cold head 5. The free end of the second cold head 5 is arranged inside the multi-stage adsorption array structure. Refrigerating gas flows in the first cold head 4 and the second cold head 5 and is used for refrigerating and cooling the multi-stage cold shield structure and the multi-stage adsorption array structure. The end of the regeneration mechanism extends into the housing 1 and is located at the end of the second cold head 5.

[0029] The utility model provides a cryogenic vacuum pump with good stability. By arranging a multi-stage cold shield structure and a multi-stage adsorption array structure, a required vacuum environment can be quickly achieved, and the stability of the vacuum state can be ensured, providing a highly clean vacuum environment for semiconductor processing. By arranging a multi-stage cold shield structure, the influence of environmental thermal radiation on the condensation and adsorption of gas by the adsorption array structure can be reduced, and the stability of the vacuum state can be ensured. By arranging a multi-stage adsorption array structure to perform multi-stage adsorption on gas molecules, the effective contact area of the gas, that is, the gas condensation or adsorption area, can be increased, the influence of the direct radiation heat of the vacuum chamber on the vacuum state can be reduced, and the required high-vacuum state can be quickly achieved. At the same time, it is also convenient for assembly and the processing accuracy is reduced. The regeneration mechanism can provide rapid regeneration for the cryogenic vacuum pump, improve the working efficiency, and make the operation more convenient.

[0030] Preferably, a driving device is arranged at the end of the first cold head 4. Refrigerating gas flows in the first cold head and the second cold head. Preferably, helium is selected as the refrigerating gas. The driving device is arranged as a driving motor to drive the reciprocating movement of a first-stage piston and a second-stage piston, perform work on the helium, and absorb heat during the compression and expansion of the helium, reducing the temperatures of the first cold head and the second cold head, achieving a low-temperature state in the cold shield and the adsorption array structure, and thus realizing the adsorption of gas molecules by the adsorption array structure at a low temperature. Preferably, the adsorption material is made of porous coconut shell activated carbon or carbon fiber material, both of which have a large specific surface area and can efficiently adsorb gas, quickly achieving a low-temperature vacuum state. The adsorption material can be obtained from the prior art, and the utility model does not involve the improvement of the material of the adsorption material. It should be noted that the inner and outer sides, upper and lower sides mentioned above are described according to the directions in the accompanying drawings of the specification, only for the convenience of describing and understanding the technical solution, and do not constitute a limitation to this application.

[0031] Based on the above technical solution, the regeneration mechanism is set as a resistance heating plate 10. In this embodiment, the regeneration mechanism adopts an electric heating method. Specifically, by arranging the regeneration mechanism at the end of the second cold head 5, the adsorption array structure and part of the cold screen structure are heated and regenerated, that is, rapid regeneration is achieved at the positions that can adsorb gas. Preferably, direct heating and regeneration using the resistance heating plate 10 can achieve rapid regeneration and high working efficiency. In a more preferred embodiment, a temperature control system is further provided. The temperature controller is used to detect the temperature at the heating position, and the temperature signal is fed back to the temperature controller. The temperature controller compares the collected temperature signal with the set point and controls the magnitude of the current output.

[0032] Based on the above technical solution, the first cold head 4 includes a primary piston 41, the second cold head 5 includes a secondary piston 51. A copper mesh 42 is arranged inside the primary piston 41, and lead pellets are filled inside the secondary piston 51. Preferably, air inlet holes and air outlet holes are provided at both ends of the primary piston 41 and / or the secondary piston 51; the refrigerating gas is helium; by providing air inlet holes and air outlet holes on the primary piston or the secondary piston or both pistons, the refrigerating gas can flow inside the primary piston or the secondary piston. Especially when flowing through the inside of the primary piston, preferably, in this embodiment, multiple layers of dense copper meshes 42 are arranged in the primary piston 41, which has the function of storing cold and absorbing heat, realizes the heat exchange of the passing helium gas, reduces the drift and fluctuation of temperature and vacuum degree, and ensures the stability of the processing environment. Lead pellets are filled inside the secondary piston 51, which also has the function of storing cold and absorbing heat, and at the same time has a filtering function. During the flow of helium gas, impurities in the helium gas can be removed, the work efficiency of helium gas can be improved, the refrigeration efficiency can be enhanced, which provides assistance for the realization of a high-vacuum environment, and ensures the stability of the vacuum environment.

[0033] In a more preferred embodiment, the piston is made of epoxy resin material. Preferably, using a piston made of epoxy resin material can reduce the phenomenon that the size is difficult to control and moisture absorption in the low-temperature region, and the size controllability and repeatability are better.

[0034] Based on the above technical solution, the multi-stage cold screen structure includes an outer cold screen 21 and an inner cold screen 22. The outer cold screen 21 is fixedly arranged on the inner side wall of the outer shell 1 and is adapted in shape. The inner cold screen 22 is arranged inside the outer cold screen 21. The inner cold screen 22 includes a plurality of annular baffles 221 which are evenly arranged from top to bottom. The surface of the annular baffle 221 is provided with an adsorption material.

[0035] By providing an outer cold screen 21 and an inner cold screen 22, the influence of environmental thermal radiation on the condensation of the adsorption array structure and the adsorbed gas can be reduced, ensuring the stability of the vacuum state; especially by providing the inner cold screen 22 structure, wherein the inner cold screen 22 is provided with a plurality of annular baffles 221, and a plurality of them are uniformly arranged along the axial direction of the cold screen from top to bottom. With this arrangement, the multiple vertical adsorption sheets 321 of the outer adsorption array 32 and the multiple horizontal annular baffles 221 in the inner cold screen 22 form a cross state, which can effectively increase the gas adsorption area, quickly achieve a high vacuum state; at the same time, reduce the thermal radiation of the adsorption array structure, lower the radiation heat load on its surface, and ensure the stability of the vacuum environment. More preferably, without affecting the gas flow, the larger the inclination angle of the annular baffle 221 and the smaller the distance between the annular baffles 221, the better its thermal shielding performance, the smaller the radiation degree on the surface of the adsorption array structure, lower the radiation heat load on its surface, achieve a better thermal shielding effect, and at the same time do not affect the normal gas channel flow, and the vacuum stability is better.

[0036] More preferably, the outer surface of the annular baffle 221 is also provided with an adsorption material; it can adsorb gas molecules, provide assistance for quickly achieving a high vacuum state, and also ensure the stability of the vacuum environment.

[0037] Based on the above technical solution, the multi-stage adsorption array structure includes a baffle 31, an outer adsorption array 32, and an inner adsorption array 33. The baffle 31 is fixedly arranged at the top of the outer cold screen 21. The outer adsorption array 32 is arranged between the outer cold screen 21 and the inner cold screen 22 and is located below the baffle 31. The inner adsorption array 33 is arranged inside the inner cold screen 22.

[0038] Based on the above technical solution, the baffle 31 includes a plurality of symmetrically arranged inclined baffles 311 and is fixedly arranged at the top of the inner side wall of the outer cold screen 21. The outer adsorption array 32 includes a plurality of adsorption sheets 321 and is uniformly arranged along the circumferential direction of the outer cold screen 21. The inner adsorption array 33 includes an outer shell plate 331 and a support frame 332. The support frame 332 is fixedly arranged inside the inner cold screen 22. The outer shell plate 331 surrounds the outside of the support frame 332 and is uniformly provided with long holes 333 on the outer shell plate 331.

[0039] Based on the above technical solution, the annular baffles 221 are all inclined inward, and the adsorption sheets 321 and the annular baffles 221 are arranged in a perpendicular relationship.

[0040] By arranging a baffle 31 inside the cold screen, preliminary adsorption and condensation of the adsorbed gas can be carried out, and at the same time, the direct impact of the gas on the internal adsorption array and the external adsorption array inside the baffle can be reduced, prolonging the service life of the internal and external adsorption arrays; by arranging two-stage adsorption of the internal adsorption array 32 and the external adsorption array 33, the effective contact area of the gas can be increased, that is, the gas condensation or adsorption area can be increased, reducing the influence of the direct radiation heat of the vacuum chamber on the vacuum state and quickly achieving the required vacuum state; at the same time, it is also convenient for assembly and reduces the processing accuracy. Specifically, the baffle 31 is arranged as a plurality of inclined baffles 311, which are arranged at the top relative to the internal and external adsorption arrays, and can form a first adsorption structure when the gas enters, can carry out gas adsorption, and can also reduce the impact of the gas on the internal structure and prolong the service life; the external adsorption array 32 is provided with a plurality of adsorption sheets 321. More preferably, the adsorption sheets 321 are inclined and a plurality of them are uniformly arranged along the circumference of the cold screen, that is, a plurality of adsorption sheets 321 are arranged vertically, which can effectively adsorb the gas and the inclined adsorption sheets 321 can increase the gas contact area and quickly achieve a high vacuum state; the internal adsorption array 33 is provided with a support frame 332 and an outer shell plate 331. Preferably, the outer shell plate 331 is arranged in a rectangular shape, which can improve the effective contact area, is easy to process and assemble at the same time, and the gas can flow through the long holes 333 on the outer shell plate 331 after entering. Combining the adsorption materials arranged on the surfaces of the outer shell plate 331 and the support frame 332, the gas analysis can be quickly adsorbed, the high vacuum state can be quickly achieved, and a stable vacuum state can be formed during operation.

[0041] On the basis of the above technical solution, it further includes a cold head housing 12, the cold head housing 12 is sleeved outside the first cold head 4 and the second cold head 5, and a sealing assembly is arranged between the first cold head 4, the second cold head 5 and the inner wall of the cold head housing 12.

[0042] On the basis of the above technical solution, the sealing assembly is a combined structure of a guide ring 6, a Gleit ring 7 and a guide ring 6 or a polytetrafluoroethylene impregnated carbon fiber sealing filler.

[0043] In one preferred embodiment, such as Figure 9As shown, one of the pistons, i.e., the first-stage piston or the second-stage piston, is taken as an example for illustration; the sealing assembly adopts a combined structure of a guide ring 6, a Gleitring 7, and a guide ring 6, which can ensure effective sealing performance and effectively extend the service life of the sealing assembly and the piston rod. Specifically, the Gleitring is a two-way sealing assembly, including a low-friction filled polytetrafluoroethylene sealing ring and an O-ring, with good heat resistance, corrosion resistance, and self-lubricating properties; it is a two-way acting rotary sealing ring that can be affected by pressure on both sides or alternating pressure; according to the cross-sectional size of the polytetrafluoroethylene sealing ring, one or two annular grooves can be processed to form a lubricating oil cavity, reducing friction, while increasing the specific pressure of the sealing surface and enhancing the sealing effect; in the case of heavy-duty two-phase piston sealing under high pressure, low pressure, and high-frequency working conditions, when there is no pressure, the sealing is achieved by the compression deformation of the O-ring and the sliding ring: when there is pressure, the O-ring fits more closely to the inner wall of the cylinder to achieve sealing. The guide ring is installed inside the piston rod assembly and mainly plays a guiding and supporting role. It can absorb radial forces during movement, improve the smoothness of the piston and piston rod during movement in the cylinder, reduce friction, prevent direct contact between metal parts, reduce the resistance of piston movement, and prevent dust and impurities from entering the inside of the cylinder, protecting the seals from damage, thereby extending the service life of the sealing system and other components; more preferably, the guide ring is made of materials such as nylon, phenolic resin, and polyoxymethylene, and has good friction resistance and fatigue resistance.

[0044] In another preferred embodiment, the sealing assembly is provided as a packing 8. The packing 8 is provided in multiple sections on the piston rod, and a gasket 9 is provided between each section. The packing 8 is a polytetrafluoroethylene-impregnated carbon fiber packing. The soft-sealing method using the packing 8 causes the packing to deform axially and radially according to the axial pre-tightening force, and the gap is filled to achieve an effective sealing state. Specifically, the carbon fiber packing is made by high-temperature carbonization of rayon or acrylic fiber, with properties such as high strength, high modulus, low density, high temperature resistance, wear resistance, and chemical corrosion resistance. Moreover, as a compression packing, it also has good elasticity and flexibility; polytetrafluoroethylene has good high and low temperature resistance, corrosion resistance, and self-lubricating properties; therefore, the carbon fiber packing impregnated with polytetrafluoroethylene in this application can effectively prevent penetration and has excellent sealing performance. Preferably, multiple sections of soft sealing packing are spaced apart to seal the piston rod, and a metal spacer is provided between the multiple sections of packing, which can not only achieve excellent sealing performance but also show excellent wear resistance of the packing and the shaft during use and has a good service life.

[0045] The basic principles and main features of the present utility model have been shown and described above. For those skilled in the art, it is obvious that the present utility model is not limited to the details of the above exemplary embodiments. Therefore, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present utility model is defined by the appended claims rather than the above description. Therefore, it is intended to embrace all changes that fall within the meaning and scope of the equivalent elements of the claims in the present utility model.

[0046] In addition, it should be understood that although this specification is described in terms of embodiments, not every embodiment only contains an independent technical solution. This narrative manner of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A cryogenic vacuum pump with good stability, characterized in that, It includes an outer housing (1), a multi-stage cold shield structure, a multi-stage adsorption array structure, a multi-stage cold head, and a regeneration mechanism. The multi-stage cold shield structure includes at least one group of cold shields and is arranged inside the outer housing (1). The multi-stage adsorption array structure is arranged inside the outer housing (1) and is used for condensing or adsorbing gas at low temperature. The multi-stage adsorption array structure includes at least one group of adsorption arrays and the outer surfaces are all provided with adsorption materials. The multi-stage cold shield structure includes an outer cold shield (21) and an inner cold shield (22). The multi-stage adsorption array structure includes a baffle (31), an outer adsorption array (32), and an inner adsorption array (33). The baffle (31) is fixedly arranged at the top of the outer cold shield (21). The outer adsorption array (32) is arranged between the outer cold shield (21) and the inner cold shield (22) and is located below the baffle (31). The inner adsorption array (33) is arranged inside the inner cold shield (22). The multi-stage cold head includes a first cold head (4) and a second cold head (5). The first cold head (4) is arranged at the end of the second cold head (5). The free end of the second cold head (5) is arranged inside the multi-stage adsorption array structure. Refrigerating gas flows in the first cold head (4) and the second cold head (5) and is used for refrigerating and cooling the multi-stage cold shield structure and the multi-stage adsorption array structure. The end of the regeneration mechanism extends into the outer housing (1) and is located at the end of the second cold head (5).

2. The cryogenic vacuum pump with good stability according to claim 1, characterized in that, The regeneration mechanism is arranged as a resistance heating plate (10).

3. The cryogenic vacuum pump with good stability according to claim 1, characterized in that, The first cold head (4) includes a first-stage piston (41). The second cold head (5) includes a second-stage piston (51). A copper mesh (42) is arranged inside the first-stage piston (41). The second-stage piston (51) is filled with lead pellets.

4. A cryogenic vacuum pump with good stability according to claim 1, characterized in that, The multi-stage cold shield structure includes an outer cold shield (21) and an inner cold shield (22). The outer cold shield (21) is fixedly arranged on the inner side wall of the outer housing (1) and is in shape adaptation. The inner cold shield (22) is arranged inside the outer cold shield (21). The inner cold shield (22) includes a plurality of annular baffles (221) which are evenly arranged from top to bottom. The surface of the annular baffle (221) is provided with adsorption materials.

5. A cryogenic vacuum pump with good stability according to claim 4, characterized in that, The multi-stage adsorption array structure includes a baffle (31), an outer adsorption array (32), and an inner adsorption array (33). The baffle (31) is fixedly arranged at the top of the outer cold shield (21). The outer adsorption array (32) is arranged between the outer cold shield (21) and the inner cold shield (22) and is located below the baffle (31). The inner adsorption array (33) is arranged inside the inner cold shield (22).

6. The cryogenic vacuum pump with good stability according to claim 5, characterized in that, The baffle (31) includes a plurality of symmetrically arranged inclined baffles (311) and is fixedly arranged at the top of the inner side wall of the outer cold shield (21). The outer adsorption array (32) includes a plurality of adsorption sheets (321) which are evenly arranged along the circumference of the outer cold shield (21). The inner adsorption array (33) includes an outer shell plate (331) and a support frame (332). The support frame (332) is fixedly arranged inside the inner cold shield (22). The outer shell plate (331) surrounds the outside of the support frame (332) and long strip holes (333) are evenly arranged on the outer shell plate (331).

7. A cryogenic vacuum pump with good stability according to claim 6, characterized in that, The annular baffles (221) are all inclined inwardly, and the adsorption sheets (321) are arranged perpendicular to the annular baffles (221).

8. A cryogenic vacuum pump with good stability according to claim 1, characterized in that, It further includes a cold head housing (12), the cold head housing (12) is sleeved outside the first cold head (4) and the second cold head (5), and a sealing assembly is arranged between the first cold head (4), the second cold head (5) and the inner wall of the cold head housing (12).

9. The cryogenic vacuum pump with good stability according to claim 8, characterized in that, The sealing assembly is a combined structure of a guide ring (6), a Gleit ring (7) and a guide ring (6) or a polytetrafluoroethylene impregnated carbon fiber sealing packing.

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