Mechanism for improving safety and prolonging service life of molecular pump and molecular pump thereof

Abstract

The invention discloses a mechanism for improving the safety and prolonging the service life of a molecular pump and the molecular pump. The mechanism comprises a rotor assembly and a movable impeller, and the movable impeller is connected to the end of a rotating shaft of the rotor assembly; an axial installation cavity is formed in the middle of the movable impeller, the rotor assembly is inserted into the axial installation cavity, a sealing assembly is further arranged at the position, close to an outer side port, in the axial installation cavity, and the sealing assembly is located on the outer side of the rotating shaft. The sealing assembly is arranged on the outer side of the axial mounting cavity of the movable impeller, so that the interior of the rotating shaft of the rotor assembly is in a higher sealing state, and corrosive gas can be prevented from entering the rotor. Besides, the flange plate of the static impeller of the molecular pump adopts the connecting holes with buffer structures and the sensor capable of detecting the loosening condition of the screws, so that the loosening condition of internal parts can be found in time, and the loss degree caused by collision between the loosened screws and other structures can be reduced; and the service life and the safety of the molecular pump are improved to a greater extent.

Description

Technical Field

[0001] The invention relates to the technical field of molecular pumps, and in particular to a mechanism for improving the safety and life of a molecular pump and a molecular pump thereof. Background Art

[0002] The magnetic levitation molecular pump draws the gas molecules in the reaction chamber into the pump through the high-speed rotating blades and discharges the gas through the front pump. The reaction chamber of the HDPCVD (high-density plasma chemical vapor deposition) equipment can quickly obtain a high vacuum environment that meets the wafer thin film deposition process through the magnetic levitation molecular pump. The molecular pump needs to maintain 100% speed for a long time when working, and no regular inspection or cleaning is performed within one year to improve the machine production capacity, so extremely high requirements are placed on the service life and safety of the molecular pump.

[0003] However, the motor rotor and impeller of the existing magnetic levitation molecular pump are connected by screws. Before the screws are connected, appropriate thread glue is applied to seal and prevent loosening, but the sealing degree is far from meeting the leakage rate standard of semiconductors. For this reason, a purge gas path is usually added inside the motor rotor to protect the motor rotor. However, the flow rate of the purge gas is fixed and cannot be dynamically adjusted according to the pressure changes of the platform. Once the chamber pressure is too high, there is a risk of corrosive gas entering the motor rotor, shortening the service life of the electrical components.

[0004] In addition, if the gas in the process condenses and crystallizes on the blades or other hardware accidentally falls into the molecular pump, there will be a risk of the blades scratching the pump wall. The high-speed blades scratching the pump wall will generate a huge emergency stop torque, causing the screws to break or the machine hardware to be damaged, and even cause serious consequences such as toxic gas leakage. Summary of the invention

[0005] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a mechanism for improving the safety and life of a molecular pump and a molecular pump thereof, so as to solve the technical problems of the short service life and low safety of the existing molecular pumps.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] In the first aspect, an embodiment of the present invention provides a mechanism for improving the safety and life of a molecular pump, which includes: a rotor assembly and an impeller, wherein the impeller is connected to the end of a rotating shaft of the rotor assembly; an axial mounting cavity is provided in the middle of the impeller, the rotor assembly is inserted into the axial mounting cavity, and a sealing assembly is also provided in the axial mounting cavity near the outer port, and the sealing assembly is located on the outer side of the rotating shaft.

[0008] Wherein, the sealing assembly is sealingly connected to the cavity wall of the axial installation cavity and is arranged close to the outer port.

[0009] Wherein, a groove is further provided on the inner wall of the axial installation cavity near the outer port, and the sealing assembly is embedded in the groove.

[0010] Wherein, the sealing assembly comprises a sealing cover plate and a sealing ring, and the sealing ring abuts against the groove and the sealing cover plate, so that a seal is formed at the contact point between the sealing cover plate and the groove.

[0011] Wherein, the sealing assembly further includes a clamping spring, which is clamped between the sealing cover plate and the groove, and the clamping spring and the sealing ring are respectively located on two side surfaces of the sealing cover plate.

[0012] Wherein, a stationary impeller cooperating with the moving impeller is also provided on the outer side of the moving impeller, and a flange is also provided on the outer end of the stationary impeller. The flange is provided with a plurality of damping connection holes, and screws are inserted into the damping connection holes.

[0013] Wherein, the damping connection hole is a waist-shaped hole, and the width of the waist-shaped hole gradually decreases in a direction away from the screw connection position.

[0014] Wherein, a plurality of buffer holes are also arranged on the peripheral flange of the damping connection hole, and the buffer holes are arranged on a side away from the screw.

[0015] Wherein, the flange is also provided with a displacement sensor, and the displacement sensor is used to detect the displacement information of the screw.

[0016] In a second aspect, an embodiment of the present invention provides a molecular pump, wherein the molecular pump includes a mechanism for improving the safety and life of the molecular pump as described in any one of the above items.

[0017] The mechanism for improving the safety and life of a molecular pump and the molecular pump thereof of the present invention provide a sealing assembly on the outer side of the axial mounting cavity of the impeller so that the inside of the rotating shaft of the rotor assembly is in a more sealed state, which can prevent corrosive gas from entering the rotor, and can prevent condensate or other components from falling into the molecular pump and damaging the molecular pump, thereby improving its safety and service life. In addition, the flange of the stationary impeller of the molecular pump adopts a connection hole of a buffer structure and a sensor capable of detecting the loosening of screws, which can not only detect the loosening of internal components in time, but also reduce the loss degree of the loose screws colliding with other structures, thereby greatly increasing the service life and safety of the molecular pump.

[0018] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the following preferred embodiments are specifically cited and described in detail as follows. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is an axial cross-sectional view of a molecular pump according to an embodiment of the present invention.

[0020] Figure 2 for Figure 1 The enlarged structural schematic diagram of local A is shown.

[0021] Figure 3 for Figure 1 The enlarged structural schematic diagram of local B is shown.

[0022] Figure 4 and Figure 5 Schematic diagram of the structure of the flange part of the mechanism for improving the safety and life of the molecular pump from different perspectives according to an embodiment of the present invention.

[0023] Figure 6 and Figure 7 This is a schematic diagram of the front and back structures of the flange portion of the mechanism for improving the safety and life of a molecular pump according to an embodiment of the present invention.

[0024] Figure 8 for Figure 4 Schematic diagram of the local C enlarged structure shown.

[0025] Fig. 9 for Figure 6 The schematic diagram of the local D enlarged structure is shown.

[0026] Description of reference numerals:

[0027] Molecular pump 100, rotor assembly 1, rotating shaft 11, moving impeller 2, moving blades 21, inner wall 22, threaded structure 221, axial mounting cavity 210, purge gas flow channel 201, stationary impeller 3, stationary blades 31, flange 30, damping connection hole 301, buffer hole 302, sealing assembly 4, sealing cover plate 41, sealing ring 42, retaining ring 43, displacement sensor 5, screw 6, gasket 61. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0030] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships described in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0031] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0032] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be connected, detachably connected, or integrated; it can be mechanically connected or electrically connected; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0033] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0034] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms should not be understood as necessarily referring to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0035] The motor rotor and impeller of the existing magnetic levitation molecular pump are connected by screws. Before the screws are connected, appropriate thread glue is applied to seal and prevent loosening, but the sealing degree is far from meeting the leakage rate standard of semiconductors. For this reason, a purge gas path is usually added inside the motor rotor to protect the motor rotor. However, the flow rate of the purge gas is fixed and cannot be dynamically adjusted according to the pressure changes of the platform. Once the chamber pressure is too high, there is a risk of corrosive gas entering the motor rotor, shortening the service life of the electrical components.

[0036] In addition, if the gas in the process condenses and crystallizes on the blades or other hardware accidentally falls into the molecular pump, there will be a risk of the blades scratching the pump wall. The high-speed blades scratching the pump wall will generate a huge emergency stop torque, causing the screws to break or the machine hardware to be damaged, and even cause serious consequences such as toxic gas leakage.

[0037] In order to solve the above problems, this embodiment discloses a molecular pump 100 with improved safety and lifespan. The connection between the rotor and the impeller of the molecular pump 100 meets the sealing performance requirements of semiconductor equipment and can also reduce the damage to the equipment caused by falling parts, thereby improving its safety and lifespan.

[0038] See also Figures 1 to 3 , Figure 1 The mechanism used to improve the safety and life of the molecular pump and the overall axial cross-sectional view of the molecular pump 100 are used to seal the connection between the rotor and the impeller of the molecular pump. Figure 2 and Figure 3 for Figure 1 The enlarged structural diagram of parts A and B in the figure mainly describes the structures in the molecular pump that improve safety and life, and other conventional structures are not described here.

[0039] The molecular pump 100 comprises: a rotor assembly 1, a moving impeller 2 controlled by the rotor assembly 1, and a stationary impeller 3 matched with the moving impeller 2. The rotor assembly 1 is a motor rotor unit structure, which is used to provide rotational power, so that when it rotates, it drives the moving impeller 2 to rotate relative to the stationary impeller 3, so that the molecules are accelerated in the cavity formed by the blades between the moving impeller 2 and the stationary impeller 3, so that the molecules collide to generate kinetic energy. Among them, a plurality of moving blades 21 are arranged on the inner side of the upper half of the moving impeller 2, and correspondingly, a stationary blade 31 is arranged on the inner side of the upper half of the stationary impeller 3, which is arranged alternately with the moving blades 21, and the cavity between the stationary blade 31 and the moving blade 21 is the acceleration cavity of the molecules.

[0040] The lower part of the stationary impeller 3 is also used to provide a mounting support mechanism for the rotor assembly 1 and a connection mechanism with other external components. The outer side of the stationary impeller 3 is also connected to a process chamber that needs to be evacuated or other equipment that needs molecular acceleration.

[0041] The mechanism for improving the safety and life of the molecular pump of this embodiment comprises: a rotor assembly 1 and a moving impeller 2, wherein the moving impeller 2 is connected to the end of the rotating shaft 11 of the rotor assembly 1; an axial mounting cavity 210 is provided in the middle of the moving impeller 2, the rotor assembly 1 is inserted into the axial mounting cavity 210, and a sealing assembly 4 is further provided in the axial mounting cavity 210 near the outer port, and the sealing assembly 4 is located on the outer side of the rotating shaft 11. When the rotor assembly 1 is powered on and rotates, the moving impeller 2 is synchronously driven to rotate coaxially with it at high speed.

[0042] See also Figure 1, the upper end of the rotating shaft 11 of the rotor assembly 1 is located in the axial mounting cavity 210 formed after the sealing assembly 4 is sealed and connected with the impeller 2. During the operation of the molecular pump, the condensate will be blocked by the sealing assembly 4 outside the axial mounting cavity 210, and the condensate will not flow from the rotating shaft 11 of the rotor assembly 1 to the inside of the rotor assembly 1, causing damage to the internal components of the motor. At the same time, since the sealing assembly 4 is added to the end of the rotor 11, even if the parts of the molecular pump may fall off due to long-term use, the sealing assembly 4 can also prevent other fallen parts from entering the motor, avoiding damage to the motor, and ultimately improving the service life and safety of the molecular pump. At the same time, the sealing assembly 4 can also prevent the parts of the motor rotor assembly 1 from falling off or impurities from entering the molecular acceleration cavity to damage the blades of the impeller. The upper end of the rotating shaft 11 is connected and locked with the impeller 2 by screws. Since the rotor assembly 1 and the impeller 2 are connected and driven by the screws, the screws here are also more likely to loosen and fall off. Of course, the sealing assembly 4 can also prevent the screws from falling off and entering the molecular acceleration cavity. Since a sealing assembly is disposed on the outer end surface of the rotating shaft 11 to form a better sealed cavity with the axial mounting cavity 210 , when used in semiconductor equipment, external corrosive gases will not enter the rotor assembly 1 and no overhead damage will occur to the components.

[0043] Please refer to the figure again, the sealing component 4 is sealed and connected to the cavity wall of the axial mounting cavity 210, and is arranged close to the outer port. It can be understood that the sealing component 4 can also be arranged at any position of the impeller 2 on the outer side of the rotor 11, and its purpose is to form a sealing structure from the outer end of the axial mounting cavity 210 of the impeller 2, so as to avoid the disadvantage of the existing gas purge method causing the gas backflow from the top due to the pressure change, and can reduce the external condensate and other impurities entering the motor rotor. Compared with the gas purge method, the sealing component 4 is not affected by the internal air pressure, and can improve the more stable and reliable sealing performance, so that the molecular pump can be used for a long time and reduce maintenance.

[0044] Specifically, a groove 20 is further provided on the inner wall of the axial installation cavity 210 near the outer port, and the sealing component 4 is embedded in the groove 20. That is, the edge of the sealing component 4 is inserted into the groove 20, and a seal is formed at the connection position between the two.

[0045] The sealing assembly 4 includes a sealing cover plate 41 and a sealing ring 42, wherein the sealing ring 42 abuts against the groove 20 and the sealing cover plate 41, so that a seal is formed at the contact between the sealing cover plate 41 and the groove 20. The sealing ring 42 is disposed in the groove 20, and the sealing cover plate 431 is pressed against the sealing ring 42, so that the sealing cover plate 41 and the groove 20 are sealed and connected through the sealing ring 42.

[0046] In order to ensure that the sealing ring 42 and the sealing cover plate 41 are dynamically and reliably pressed together, the sealing assembly 4 further includes a clamping spring 43, which is clamped between the sealing cover plate 41 and the groove 20, and the clamping spring 43 and the sealing ring 42 are respectively located on the two side surfaces of the sealing cover plate 41. Figure 2 As shown, the sealing ring 42 is pressed onto the bottom surface of the sealing cover plate 41, and the retaining spring 43 is arranged on the top surface of the sealing cover plate 41. At the same time, the retaining spring 43 also abuts against the top wall of the groove 20. The sealing cover plate 41 is dynamically pressed onto the top of the sealing ring 42 by the retaining spring 43. Even if the impeller 2 rotates at a high speed, the sealing cover plate 41 can keep the sealing cover plate 41 and the sealing ring 42 tightly pressed when the rotor 11 is axially disturbed, so as to form a better sealing state.

[0047] Please refer again Figure 1 and Figure 3 The structure for improving the safety and life of the molecular pump in this embodiment also includes a spiral structure 221 disposed on the inner wall 22 of the lower side of the axial mounting cavity 210 of the impeller 2. The spiral structure 221 is a spiral protrusion extending along the inner wall of the axial mounting cavity 210, similar to a protrusion thread. The thread structure 221 is used to guide the purge gas and prevent the external gas from flowing back into the purge gas flow channel 201, thereby improving the output smoothness of the purge gas. Figure 1 As shown, the direction indicated by the arrow in the figure is the flow direction of the purge gas, and a purge gas flow channel 201 is formed between the outer wall of the rotor assembly 1 and the wall of the axial mounting cavity 210 of the impeller 2.

[0048] As can be seen from the figure, the spiral structure 221 is only provided at the end portion of the purge gas flow channel 201, that is, close to the outlet of the molecular pump, for quickly directing the purge gas to the secondary pump or the outside of the molecular pump.

[0049] Please refer again Figures 4 to 9 The outer side of the moving impeller 2 is also provided with a stationary impeller 3 matched with the moving impeller 2, and the outer end of the stationary impeller 3 is also provided with a flange 30, and the flange 30 is provided with a plurality of damping connection holes 301, and the damping connection holes 301 are penetrated by screws 6.

[0050] Since the inlet flange 30 of the molecular pump is connected to the outer wall of the pump body by screws 6, if there are impurities or parts falling, the impeller will collide and scratch with the pump body. In order to reduce the damage to the impeller caused by collision and scratch, the connection structure between the stationary impeller 3 and the pump body is improved to a connection structure of damping connection hole 301 screw 6. When collision or scratch occurs, the damping connection hole 301 can buffer the screw 6 and reduce the vibration damage caused by blade collision or scratch.

[0051] In this embodiment, the damping connection hole 301 is a waist-shaped hole, and the width of the waist-shaped hole gradually decreases in the direction away from the connection position of the screw 6. That is, the width between the opposite side walls in the length direction of the damping connection hole 301 gradually decreases, and the opposite side walls are roughly in an isosceles trapezoidal shape. When the impeller collides, the screw 6 will deviate and move along the damping connection hole 301, but the greater the moving stroke, the greater the resistance, which produces a buffering effect on the screw 6.

[0052] For details, please refer to Figure 8 and Fig. 9 , a plurality of buffer holes 302 are also provided on the peripheral flange 30 of the damping connection hole 301, and the buffer holes 302 are arranged on the side away from the screw 6. That is, in the normal working state of the molecular pump, the screw 6 is connected to the side of the damping connection hole 301 away from the buffer hole 302, and at this time, the damping connection hole 301 on the outer side of the screw 6 is not provided with a buffer hole structure. When a collision occurs, the screw 6 will move to the side of the buffer hole 302, and the buffer hole 302 will collapse, thereby playing a buffering role for the screw 6.

[0053] In this embodiment, the buffer hole 302 is a honeycomb hole. In other embodiments, the buffer hole 302 can be any other shape, and its purpose is to collapse when squeezed by the screw 6, so as to have a buffering effect on the screw 6. A gasket 61 is also provided between the screw 6 and the damping connection hole 301, and the gasket 61 is penetrated by the screw 6.

[0054] The plurality of damping connection holes 301 are distributed on the flange 30 in a circular shape.

[0055] Please refer again Figure 4 and Figure 8 The flange 30 is also provided with a displacement sensor 5, which is used to detect the displacement information of the screw 6. The displacement sensor 5 includes an optical sensor or other sensor capable of detecting the displacement of an object. The displacement sensor 5 detects the position of the screw 6 in real time. When the screw 6 is loose, the displacement sensor 6 can detect its displacement information in time, and the controller triggers a fault alarm and a shutdown mechanism according to the displacement information, thereby avoiding damage to the internal mechanism of the molecular pump caused by the falling of components.

[0056] An embodiment of the present invention provides a molecular pump 100 , wherein the molecular pump 100 includes the mechanism for improving the safety and life of the molecular pump as described above.

[0057] The mechanism for improving the safety and life of a molecular pump and the molecular pump thereof of the present invention provide a sealing assembly on the outer side of the axial mounting cavity of the impeller so that the inside of the rotating shaft of the rotor assembly is in a more sealed state, which can prevent corrosive gas from entering the rotor, and can prevent condensate or other components from falling into the molecular pump and damaging the molecular pump, thereby improving its safety and service life. In addition, the flange of the stationary impeller of the molecular pump adopts a connection hole of a buffer structure and a sensor capable of detecting the loosening of screws, which can not only detect the loosening of internal components in time, but also reduce the loss degree of the loose screws colliding with other structures, thereby greatly increasing the service life and safety of the molecular pump.

[0058] The above examples are only used to further illustrate the technical content of the present invention, so that readers can understand it more easily, but they do not mean that the implementation of the present invention is limited to this. Any technical extension or re-creation made according to the present invention is protected by the present invention. The protection scope of the present invention shall be subject to the claims.

Claims

1. A mechanism for improving the safety and life of a molecular pump, characterized in that: include: A rotor assembly and an impeller, wherein the impeller is connected to the end of the rotating shaft of the rotor assembly; an axial mounting cavity is provided in the middle of the impeller, the rotor assembly is inserted into the axial mounting cavity, and a sealing assembly is also provided in the axial mounting cavity near the outer port, and the sealing assembly is located on the outer side of the rotating shaft.

2. The mechanism for improving the safety and life of a molecular pump according to claim 1, characterized in that: The sealing assembly is sealingly connected to the cavity wall of the axial installation cavity and is arranged close to the outer port.

3. The mechanism for improving the safety and life of a molecular pump according to claim 2, characterized in that: A groove is also provided on the inner wall of the axial installation cavity near the outer port, and the edge of the sealing component is embedded in the groove.

4. The mechanism for improving the safety and life of a molecular pump according to claim 3, characterized in that: The sealing assembly comprises a sealing cover plate and a sealing ring, wherein the sealing ring abuts against the groove and the sealing cover plate, so that a seal is formed at the contact point between the sealing cover plate and the groove.

5. The mechanism for improving the safety and life of a molecular pump according to claim 4, characterized in that: The sealing assembly further comprises a clamping spring, which is clamped between the sealing cover plate and the groove, and the clamping spring and the sealing ring are respectively located on two side surfaces of the sealing cover plate.

6. The mechanism for improving the safety and life of a molecular pump according to any one of claims 1 to 5, characterized in that: A stationary impeller cooperating with the moving impeller is also arranged on the outer side of the moving impeller, and a flange is also arranged on the outer end of the stationary impeller. A plurality of damping connection holes are arranged on the flange, and screws are inserted into the damping connection holes.

7. The mechanism for improving the safety and life of a molecular pump according to claim 6, characterized in that: The damping connection hole is a waist-shaped hole, and the width of the waist-shaped hole gradually decreases in a direction away from the screw connection position.

8. The mechanism for improving the safety and life of a molecular pump according to claim 7, characterized in that: A plurality of buffer holes are also arranged on the peripheral flange of the damping connection hole, and the buffer holes are arranged on a side away from the screw.

9. The mechanism for improving the safety and life of a molecular pump according to claim 6, characterized in that: The flange is also provided with a displacement sensor, which is used to detect the displacement information of the screw.

10. A molecular pump, characterized in that: The molecular pump comprises a mechanism for improving the safety and life of the molecular pump as described in any one of claims 1 to 9.

Images