A double-layer magnetic fluid sealing device and vapor deposition equipment

Abstract

The present invention relates to the technical field of vapor deposition equipment, in particular to a double-layer magnetic fluid sealing device and vapor deposition equipment. The double-layer magnetic fluid sealing device includes a vacuum chamber, a reaction tray, a rotating shaft assembly, a heating assembly, a rotating assembly, a first sealing device and a second sealing device. The rotating shaft assembly includes an inner shaft body, an outer shaft body and a bearing. The outer shaft body is fixedly connected to the vacuum chamber. The inner shaft body is rotatably installed in the outer shaft body through the bearing. The top of the inner shaft body is fixedly connected to the reaction tray. The heating assembly is arranged in the inner shaft body. The first sealing device is arranged between the inner shaft body and the outer shaft body; the second sealing device is arranged between the inner shaft body and the outer shaft body. By building the electrode into the rotating shaft assembly and using a double-layer magnetic fluid sealing device to isolate the vacuum environment, the external environment and the electrode protection gas environment respectively, the problem of exposed electrode oxidation is solved, and the independent sealing of multiple gas environments is achieved at the same time.

Description

Technical Field

[0001] The present invention relates to the technical field of vapor deposition equipment, in particular to a double-layer magnetic fluid sealing device and vapor deposition equipment. Background Art

[0002] In existing vapor deposition equipment, electrodes are typically exposed outside the chamber. These electrodes are susceptible to oxidation corrosion in high-temperature, high-vacuum environments, leading to poor contact or failure. Introducing inert gas to isolate oxygen from direct contact with the electrodes effectively addresses this oxidation issue. However, conventional single-layer magnetic fluid seals cannot simultaneously meet the dual requirements of sealing the electrode chamber with inert gas protection and the process gas environment. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to solve one or more technical problems existing in the prior art and at least provide a beneficial option or create conditions.

[0004] The present invention solves its technical problem by providing a double-layer magnetic fluid sealing device, comprising a vacuum chamber, a reaction tray, a rotating shaft assembly, a heating assembly, a rotating assembly, a first sealing device, and a second sealing device. A first space is defined in the vacuum chamber; the reaction tray is disposed in the first space for placing a workpiece; the rotating shaft assembly extends into the first space, the rotating shaft assembly comprising an inner shaft body, an outer shaft body, and a bearing; the outer shaft body is fixedly connected to the vacuum chamber; the inner shaft body is rotatably mounted in the outer shaft body via the bearing; the top of the inner shaft body is fixedly connected to the reaction tray; a second space is defined within the inner shaft body; the heating assembly is disposed in the second space for heating the reaction tray; the rotating assembly is transmission-connected to the middle portion of the inner shaft body, and the rotating assembly drives the inner shaft body to rotate the reaction tray; the first sealing device is disposed between the inner shaft body and the outer shaft body, and is located above the rotating assembly, for isolating the first space from air; the second sealing device is disposed between the inner shaft body and the outer shaft body, and is located below the rotating assembly, for isolating the second space from air.

[0005] The beneficial effects of the present invention are as follows: the vacuum chamber provides a relatively closed first space, providing the vacuum environment required for the process; the reaction tray carries the workpiece to be processed during the vapor deposition process; the inner shaft is rotatably installed in the outer shell through a bearing, and the top of the inner shaft is fixedly connected to the reaction tray. The reaction tray is driven by the rotating component to rotate, ensuring that all parts of the workpiece can be evenly heated and evenly receive the deposited material during the deposition process, thereby ensuring the consistency of the process effect; the second space set inside the inner shaft is used to place the heating component to heat the reaction tray, and inert gas is introduced into the interior to prevent oxidation of the electrode in the heating component; the first sealing device isolates the first space from the air to prevent outside air from entering the vacuum environment that affects the vapor deposition process and has adverse effects on internal components; the second sealing device isolates the second space from the air to ensure that the second space where the heating component is located is in an inert gas environment to prevent oxidation of the electrode from contacting with oxygen. By building the heating component into the rotating shaft component, the traditional situation where the electrode is exposed and easily oxidized is changed. With the help of a double-layer magnetic fluid sealing device, the vacuum environment, external environment and electrode protection gas environment are isolated respectively, and the independent sealing of multiple gas environments is achieved, so that the gas environments of different functional areas do not interfere with each other and each is maintained in an ideal state; the vacuum environment can maintain a high vacuum degree which is conducive to deposition, and the inert gas environment where the heating component is located can ensure the safety of the electrode in the heating component, which helps to improve the deposition quality and production efficiency of the workpiece.

[0006] As a further improvement of the above technical solution, the first sealing device includes a first permanent magnet, a first pole shoe and a first magnetic fluid, the first permanent magnet and the first pole shoe are arranged on the inner wall of the outer shell, the first pole shoe is arranged on both sides of the first permanent magnet, a first magnetic fluid groove is provided on the outer wall of the inner shaft body, the first magnetic fluid is arranged in the first magnetic fluid groove, the first pole shoe, the first permanent magnet and the inner shaft body constitute a first magnetic circuit, and the first magnetic fluid forms a first liquid O-ring for sealing the first space under the action of the first magnetic circuit.

[0007] As a further improvement of the above technical solution, the second sealing device includes a second permanent magnet, a second pole shoe and a second magnetic fluid. The second permanent magnet and the second pole shoe are arranged on the inner wall of the outer shell, the second pole shoe is arranged on both sides of the second permanent magnet, and a second magnetic fluid groove is provided on the outer wall of the inner shaft body. The second magnetic fluid is arranged in the second magnetic fluid groove. The second pole shoe, the second permanent magnet and the inner shaft body constitute a second magnetic circuit. Under the action of the second magnetic circuit, the second magnetic fluid forms a second liquid O-ring for sealing the second space.

[0008] As a further improvement to the above technical solution, the magnetic poles of the first permanent magnet and the second permanent magnet are arranged in opposite directions.

[0009] As a further improvement of the above technical solution, the heating component includes an electric heating coil and an electrode, one end of the electrode is passed through the outer shell, and the other end of the electrode extends into the second space, the electric heating coil is arranged on the top of the electrode, and the electric heating coil is electrically connected to the electrode.

[0010] As a further improvement of the above technical solution, the rotating assembly includes a motor, a driving wheel, a driven wheel and a synchronous belt. The motor is arranged on one side of the rotating shaft assembly, the driving wheel is arranged to rotate coaxially with the driving part of the motor, the driven wheel is sleeved on the inner shaft body, the driven wheel is arranged to rotate coaxially with the inner shaft body, and the driving wheel is connected to the driven wheel through the synchronous belt.

[0011] As a further improvement of the above technical solution, the double-layer magnetic fluid sealing device also includes a vacuum pipe and a vacuum pump. The vacuum pipe is arranged on the vacuum cavity, and the first space is connected to the vacuum pump through the vacuum pipe.

[0012] As a further improvement of the above technical solution, the double-layer magnetic fluid sealing device also includes an air pipeline and an external air source, the air pipeline is arranged on the outer shell, and the second space is connected to the external air source through the air pipeline.

[0013] As a further improvement of the above technical solution, the double-layer magnetic fluid sealing device further includes a first sealing member, which is arranged between the vacuum cavity and the outer shell to seal the vacuum cavity and the outer shell.

[0014] A vapor deposition device comprises the double-layer magnetic fluid sealing device described in any one of the above items. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic structural diagram of a CVD device with a double-layer magnetic fluid sealing device according to an embodiment of the present invention;

[0016] Figure 2 is a cross-sectional view of a CVD apparatus with a double-layer magnetic fluid sealing device according to an embodiment of the present invention;

[0017] Figure 3 is a schematic structural diagram of a first sealing device according to an embodiment of the present invention;

[0018] Figure 4 It is a schematic structural diagram of a second sealing device according to an embodiment of the present invention.

[0019] In the accompanying drawings: 100-vacuum chamber, 200-reaction tray, 310-inner shaft, 311-first magnetic liquid tank, 312-second magnetic liquid tank, 320-outer shell, 330-bearing, 400-heating component, 410-electric heating coil, 420-electrode, 500-first sealing device, 510-first permanent magnet, 520-first pole shoe, 530-first magnetic fluid, 600-rotating component, 610-motor, 620-driving wheel, 630-driven wheel, 640-synchronous belt, 700-second sealing device, 710-second permanent magnet, 720-second pole shoe, 730-second magnetic fluid, 810-vacuum pipe, 820-gas pipe, 900-first sealing member. DETAILED DESCRIPTION

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention, the above briefly describes the drawings required for describing the embodiments. Obviously, the drawings described only represent some embodiments of the present invention, not all embodiments. Those skilled in the art can also derive other design solutions and drawings based on these drawings without inventive effort.

[0021] The following will clearly and completely describe the concept, specific structure and technical effects of the present invention in combination with the embodiments and drawings, so as to fully understand the purpose, characteristics and effects of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention. In addition, all the connection / connection relationships mentioned in the text do not refer to the direct connection of components, but refer to the fact that a better connection structure can be formed by adding or reducing connection accessories according to the specific implementation situation. The various technical features in the present invention can be combined interchangeably without conflicting with each other.

[0022] In existing vapor deposition equipment, the electrode 420 is typically exposed outside the chamber. This exposure to high temperature and high vacuum can lead to oxidation corrosion, resulting in poor contact or failure of the electrode 420. Introducing an inert gas to isolate oxygen from direct contact with the electrode 420 can effectively address this oxidation issue. However, conventional single-layer magnetic fluid seals cannot simultaneously meet the dual requirements of sealing the electrode 420 within the inert gas protection chamber and the process gas environment.

[0023] To this end, the present invention proposes a double-layer magnetic fluid sealing device, referring to Figures 1 to 4, which includes a vacuum chamber 100, a reaction tray 200, a rotating shaft assembly, a heating assembly 400, a rotating assembly 600, a first sealing device 500 and a second sealing device 700, wherein a first space is provided in the vacuum chamber 100; the reaction tray 200 is arranged in the first space for placing a workpiece; the rotating shaft assembly extends into the first space, and the rotating shaft assembly includes an inner shaft body 310, an outer shaft body 320 and a bearing 330, the outer shaft body 320 is fixedly connected to the vacuum chamber 100, the inner shaft body 310 is rotatably mounted in the outer shaft body 320 through the bearing 330, the top of the inner shaft body 310 is fixedly connected to the reaction tray 200, and the inner A second space is provided inside the shaft body 310; the heating assembly 400 is arranged in the second space for heating the reaction tray 200; the rotating assembly 600 is transmission-connected to the middle part of the inner shaft body 310, and the rotating assembly 600 drives the inner shaft body 310 to rotate the reaction tray 200; the first sealing device 500 is arranged between the inner shaft body 310 and the outer shell 320, and is located above the rotating assembly 600, for isolating the first space from the air; the second sealing device 700 is arranged between the inner shaft body 310 and the outer shell 320, and is located below the rotating assembly 600, for isolating the second space from the air.

[0024] The vacuum chamber 100 provides a relatively enclosed first space, which provides the vacuum environment required for the process. The reaction tray 200 carries the workpiece to be processed during the vapor deposition process. The inner shaft 310 is rotatably mounted within the outer housing 320 via a bearing 330. The top of the inner shaft 310 is fixedly connected to the reaction tray 200. Driven by the rotation assembly 600, the reaction tray 200 rotates to ensure that all parts of the workpiece are evenly heated and receive the deposited material during the deposition process, thereby ensuring consistent process results. A second space provided within the inner shaft 310 is used to house the heating assembly 400 to heat the reaction tray 200. Inert gas is introduced into the space to prevent oxidation of the electrode 420 in the heating assembly 400. A first sealing device 500 isolates the first space from the air, preventing outside air from entering and affecting the vacuum environment of the vapor deposition process and adversely affecting internal components. A second sealing device 700 isolates the second space from the air, ensuring that the second space where the heating assembly 400 is located is in an inert gas environment, preventing oxidation of the electrode 420 from contact with oxygen. By building the heating component 400 into the rotating shaft component, the situation in which the traditional electrode 420 is exposed and easily oxidized is changed. With the help of a double-layer magnetic fluid sealing device, the vacuum environment, the external environment and the protective gas environment of the electrode 420 are isolated respectively, thereby realizing independent sealing of multiple gas environments, so that the gas environments of different functional areas do not interfere with each other and each is maintained in an ideal state; the vacuum environment can maintain a high vacuum degree which is conducive to deposition, and the inert gas environment where the heating component 400 is located can ensure the safety of the electrode 420 in the heating component 400, which helps to improve the deposition quality and production efficiency of the workpiece.

[0025] During the vapor deposition process, the vacuum chamber 100 maintains the vacuum environment of the first space, the rotating assembly 600 drives the inner shaft 310 in the rotating shaft assembly to rotate, and the inner shaft 310 drives the reaction tray 200 fixed thereto to rotate, so that the workpiece placed on the reaction tray 200 can be evenly heated and evenly receive the deposited material; at the same time, the heating assembly 400 in the second space inside the inner shaft 310 heats the reaction tray 200, inert gas is introduced into the second space, and the air is isolated by the second sealing device 700 to prevent oxidation of the electrode 420; the first sealing device 500 isolates the outside air from the first space to ensure that the vacuum environment is not disturbed by the outside air; the double-layer magnetic fluid sealing device ensures the independence and stability of the gas environment of each functional area, so that the entire vapor deposition process can proceed smoothly.

[0026] External air may enter the first space, destroying the vacuum environment required for the vapor deposition process, causing changes in the composition of the process gas, etc., and affecting the adhesion and reaction effect of the deposited material on the workpiece surface. Therefore, in one embodiment, the first sealing device 500 includes a first permanent magnet 510, a first pole shoe 520 and a first magnetic fluid 530, the first permanent magnet 510 and the first pole shoe 520 are arranged on the inner wall of the outer shell 320, the first pole shoe 520 is arranged on both sides of the first permanent magnet 510, the outer wall of the inner shaft 310 is provided with a first magnetic fluid groove 311, the first magnetic fluid 530 is arranged in the first magnetic fluid groove 311, the first pole shoe 520, the first permanent magnet 510 and the inner shaft 310 constitute a first magnetic circuit, and the first magnetic fluid 530 forms a first liquid O-ring for sealing the first space under the action of the first magnetic circuit. When the vapor deposition equipment is running, the first permanent magnet 510 generates a magnetic field, which is guided and gathered by the first pole shoes 520 on both sides to form a stable and effective first magnetic circuit; the first magnetic fluid 530 will change its shape under the action of the magnetic field of the first magnetic circuit to form a liquid sealing structure similar to an O-ring, which fits tightly between the inner shaft 310 and the outer shell 320, thereby effectively isolating the first space from the outside air, ensuring that the vacuum environment and the process gas environment in the first space are not disturbed by the outside air, and maintaining the vapor deposition process in a suitable environment.

[0027] Outside air may enter the second space, destroying the inert gas environment originally used to protect the electrode 420, causing oxidation corrosion of the electrode 420, and affecting the normal heating function of the heating assembly 400. Therefore, in one embodiment, the second sealing device 700 includes a second permanent magnet 710, a second pole shoe 720, and a second magnetic fluid 730. The second permanent magnet 710 and the second pole shoe 720 are arranged on the inner wall of the outer shell 320, and the second pole shoe 720 is arranged on both sides of the second permanent magnet 710. The outer wall of the inner shaft 310 is provided with a second magnetic fluid groove 312, and the second magnetic fluid 730 is arranged in the second magnetic fluid groove 312. The second pole shoe 720, the second permanent magnet 710, and the inner shaft 310 constitute a second magnetic circuit. Under the action of the second magnetic circuit, the second magnetic fluid 730 forms a second liquid O-ring for sealing the second space. The second permanent magnet 710 generates a magnetic field and forms a second magnetic circuit under the guidance and gathering action of the second pole shoe 720; the second magnetic fluid 730 forms a liquid sealing structure similar to an O-ring under the action of the magnetic field of the second magnetic circuit, which fits tightly between the inner shaft 310 and the outer shell 320, thereby achieving effective sealing of the second space; so that the inert gas environment in the second space can be maintained to prevent the mixing of external air, and to ensure that the electrode 420 in the heating component 400 will not be oxidized due to contact with oxygen, etc., to ensure that the entire vapor deposition process can proceed normally as required; the second sealing device 700 cooperates with the first sealing device 500 to achieve independent sealing of the gas environment in different functional areas, ensuring that the gas environment in each area does not interfere with each other, which helps to maintain the stability of the vapor deposition process, improve the deposition quality of the workpiece and improve the production efficiency of the entire equipment.

[0028] The magnetic fields generated by the first permanent magnet 510 and the second permanent magnet 710 may interfere with each other, overlap and cause chaos, thereby weakening the sealing ability of the first space and the second space. Therefore, in one embodiment, the magnetic poles of the first permanent magnet 510 and the second permanent magnet 710 are arranged in opposite directions. The opposite directions of the magnetic poles make the magnetic circuits formed by the first sealing device 500 and the second sealing device 700 relatively independent, avoiding mutual interference between the magnetic fields, thereby allowing the first liquid O-ring and the second liquid O-ring to perform a sealing function more stably and effectively, ensuring that the sealing effects of the first space and the second space do not affect each other, maintaining their respective ideal gas environments, and ensuring the smooth progress of different links in the vapor deposition process.

[0029] In the high-temperature, high-vacuum operating environment of a vapor deposition device, the electrode 420 in the heating assembly 400 may be oxidatively corroded by oxygen, resulting in poor contact or even failure. Therefore, in one embodiment, the heating assembly 400 includes an electric heating coil 410 and an electrode 420 . One end of the electrode 420 is disposed on the outer shell 320 , and the other end of the electrode 420 extends into the second space. The electric heating coil 410 is disposed on top of the electrode 420 , and the electric heating coil 410 and the electrode 420 are electrically connected. One end of the electrode 420 is passed through the outer shell 320 to introduce current from an external power source; the electric heating coil 410 converts the current transmitted by the electrode 420 into heat energy, providing continuous and stable heat for the reaction tray 200 and the workpiece; the second space into which the electrode 420 extends is isolated from the outside air by the second sealing device 700, creating an inert gas environment to avoid oxidation caused by contact with external oxygen, thereby maximizing the service life of the electrode 420 and maintaining the good performance of the heating component 400; reasonably saving space, avoiding space waste, preventing spatial interference problems between components, and maintaining the compactness of the overall structure of the device.

[0030] The power transmission of the rotating assembly 600 may fluctuate or be interrupted, resulting in unstable rotation of the reaction tray 200 and affecting the deposition quality. Therefore, in one embodiment, the rotating assembly 600 includes a motor 610, a driving wheel 620, a driven wheel 630, and a synchronous belt 640. The motor 610 is arranged on one side of the rotating shaft assembly, the driving wheel 620 is arranged to rotate coaxially with the driving portion of the motor 610, the driven wheel 630 is sleeved on the inner shaft body 310, the driven wheel 630 is arranged to rotate coaxially with the inner shaft body 310, and the driving wheel 620 is connected to the driven wheel 630 through the synchronous belt 640. The motor 610 drives the driving wheel 620, which rotates coaxially with it, to rotate through the driving portion. The driving wheel 620 then transmits power to the driven wheel 630, which is sleeved on the inner shaft body 310 and rotates coaxially with it, via the synchronous belt 640, ultimately achieving rotation of the inner shaft body 310 and driving the reaction tray 200 to rotate. The synchronous belt 640 buffers the power fluctuation output by the motor 610 to a certain extent, making the rotational power transmitted to the reaction tray 200 more stable and continuous, ensuring that the workpiece can rotate continuously and evenly during the deposition process, ensuring the consistency of the process effect.

[0031] In one embodiment, the double-layer magnetic fluid sealing device further includes a vacuum pipe 810 and a vacuum pump. The vacuum pipe 810 is provided on the vacuum chamber 100, and the first space is connected to the vacuum pump via the vacuum pipe 810. The vacuum pump continuously extracts the gas in the first space through the vacuum pipe 810, creating a high vacuum environment required for the vapor deposition process, so that the deposited material can better undergo deposition reaction on the workpiece surface under such low pressure, thereby improving the deposition quality and efficiency. In coordination with the first sealing device 500, the vacuum pipe 810 and the vacuum pump are responsible for creating and maintaining the vacuum environment, while the sealing device prevents external air from reversely entering the first space and destroying the vacuum environment. The two complement each other and jointly ensure the independence and stability of the vacuum environment in the first space.

[0032] In one embodiment, the double-layer magnetic fluid sealing device further includes an air conduit 820 and an external air source. The air conduit 820 is disposed on the outer shell 320, and the second space is connected to the external air source via the air conduit 820. The external air source provides an inert gas (argon, nitrogen, etc.), which is delivered to the second space via the air conduit 820. Combined with the sealing effect of the second sealing device 700 on the second space, this continuously and stably maintains an inert gas environment within the second space, effectively isolating oxygen and preventing oxidation of the electrode 420. This ensures good electrical conductivity and a long service life for the electrode 420, thereby ensuring stable operation of the heating assembly 400.

[0033] The installation gap between the vacuum chamber 100 and the outer shell 320 may cause outside air to enter or internal process gas to escape. Therefore, in one embodiment, the double-layer magnetic fluid sealing device further includes a first seal 900, which is disposed between the vacuum chamber 100 and the outer shell 320 to seal the vacuum chamber 100 and the outer shell 320. By effectively sealing the connection between the vacuum chamber 100 and the outer shell 320, outside air is prevented from entering the interior through the connection gap between the vacuum chamber 100 and the outer shell 320, thereby avoiding damage to the environment required for the process; a good sealing connection can avoid problems such as poor contact and corrosion of internal components due to gas leakage, reducing the probability of equipment failure due to poor sealing.

[0034] A vapor deposition device comprises the double-layer magnetic fluid sealing device described in any one of the above items.

[0035] The double-layer magnetic fluid sealing device can effectively create and maintain a stable vacuum environment and an independent and ideal gas environment in each functional area. The stable process environment helps the vapor deposition process to proceed smoothly and efficiently, reducing downtime caused by process problems, equipment failures, etc. The workpiece can be deposited quickly and with high quality under ideal conditions, thereby improving the production efficiency of the vapor deposition equipment.

[0036] The above specifically describes the preferred embodiments of the present invention, but the present invention is not limited to the embodiments. Those skilled in the art can make various equivalent modifications or substitutions without violating the spirit of the present invention. These equivalent modifications or substitutions are all included in the scope defined by the claims of this application.

Claims

1. A double-layer magnetic fluid sealing device, characterized in that: include: A vacuum cavity (100), wherein a first space is provided in the vacuum cavity (100); a reaction tray (200), the reaction tray (200) being arranged in the first space and being used for placing a workpiece; A rotating shaft assembly, the rotating shaft assembly extends into the first space, the rotating shaft assembly comprises an inner shaft body (310), an outer shaft body (320) and a bearing (330), the outer shaft body (320) is fixedly connected to the vacuum chamber (100), the inner shaft body (310) is rotatably mounted in the outer shaft body (320) via the bearing (330), the top of the inner shaft body (310) is fixedly connected to the reaction tray (200), and a second space is provided inside the inner shaft body (310); a heating component (400), the heating component (400) being arranged in the second space and being used to heat the reaction tray (200); A rotating assembly (600), the rotating assembly (600) being in transmission connection with the middle portion of the inner shaft (310), the rotating assembly (600) driving the inner shaft (310) to drive the reaction tray (200) to rotate; a first sealing device (500), the first sealing device (500) being arranged between the inner shaft (310) and the outer shell (320) and located above the rotating assembly (600), and being used to isolate the first space from air; a second sealing device (700), the second sealing device (700) being arranged between the inner shaft (310) and the outer shell (320) and located below the rotating assembly (600), and being used to isolate the second space from air; The first sealing device (500) includes a first permanent magnet (510), a first pole shoe (520) and a first magnetic fluid (530), wherein the first permanent magnet (510) and the first pole shoe (520) are arranged on the inner wall of the outer shell (320), the first pole shoe (520) is arranged on both sides of the first permanent magnet (510), a first magnetic fluid groove (311) is provided on the outer wall of the inner shaft (310), and the first magnetic fluid (530) is arranged in the first magnetic fluid groove (311), the first pole shoe (520), the first permanent magnet (510) and the inner shaft (310) constitute a first magnetic circuit, and the first magnetic fluid (530) forms a first liquid O-ring for sealing the first space under the action of the first magnetic circuit.

2. The double-layer magnetic fluid sealing device according to claim 1, characterized in that: The second sealing device (700) includes a second permanent magnet (710), a second pole shoe (720) and a second magnetic fluid (730), wherein the second permanent magnet (710) and the second pole shoe (720) are arranged on the inner wall of the outer shell (320), the second pole shoe (720) is arranged on both sides of the second permanent magnet (710), a second magnetic fluid groove (312) is provided on the outer wall of the inner shaft (310), and the second magnetic fluid (730) is arranged in the second magnetic fluid groove (312), the second pole shoe (720), the second permanent magnet (710) and the inner shaft (310) constitute a second magnetic circuit, and the second magnetic fluid (730) forms a second liquid O-ring for sealing the second space under the action of the second magnetic circuit.

3. The double-layer magnetic fluid sealing device according to claim 2, characterized in that: The magnetic poles of the first permanent magnet (510) and the second permanent magnet (710) are arranged in opposite directions.

4. The double-layer magnetic fluid sealing device according to claim 1, characterized in that: The heating component (400) comprises an electric heating coil (410) and an electrode (420), one end of the electrode (420) is inserted into the outer shell (320), and the other end of the electrode (420) extends into the second space, the electric heating coil (410) is arranged on top of the electrode (420), and the electric heating coil (410) is electrically connected to the electrode (420).

5. The double-layer magnetic fluid sealing device according to claim 1, characterized in that: The rotating assembly (600) comprises a motor (610), a driving wheel (620), a driven wheel (630) and a synchronous belt (640), wherein the motor (610) is arranged on one side of the rotating shaft assembly, the driving wheel (620) is arranged to rotate coaxially with the driving portion of the motor (610), the driven wheel (630) is sleeved on the inner shaft body (310), the driven wheel (630) is arranged to rotate coaxially with the inner shaft body (310), and the driving wheel (620) is connected to the driven wheel (630) through the synchronous belt (640).

6. The double-layer magnetic fluid sealing device according to claim 1, characterized in that: The double-layer magnetic fluid sealing device further comprises a vacuum pumping pipe (810) and a vacuum pump. The vacuum pumping pipe (810) is arranged on the vacuum cavity (100), and the first space is connected to the vacuum pump via the vacuum pumping pipe (810).

7. The double-layer magnetic fluid sealing device according to claim 1, characterized in that: The double-layer magnetic fluid sealing device further comprises an air pipeline (820) and an external air source, wherein the air pipeline (820) is arranged on the outer shell (320), and the second space is connected to the external air source via the air pipeline (820).

8. The double-layer magnetic fluid sealing device according to claim 1, characterized in that: The double-layer magnetic fluid sealing device further comprises a first sealing member (900), wherein the first sealing member (900) is arranged between the vacuum cavity (100) and the outer shell (320) to seal the vacuum cavity (100) and the outer shell (320).

9. A vapor deposition device, characterized in that: The invention comprises a double-layer magnetic fluid sealing device according to any one of claims 1 to 8.

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