vacuum pump

Abstract

A vacuum pump comprising a sputter ion pump (SIP) module having a first end and a second end, a non-evaporative getter (NEG) module coupled to the second end of the SIP module, and a conductor of the NEG module extending from the first end to the second end of the SIP module, wherein the SIP module comprises an anode having a first surface and a second surface on the opposite side, with at least a cylindrical opening extending from the first surface to the second surface, the anode further comprising a side extending from the first surface to the second surface, and the conductor being arranged on the side of the anode.

Description

Technical Field

[0001] The present invention relates to a vacuum pump, and more particularly to a vacuum pump including a sputter ion pump (SIP) module and a non-evaporable getter (NEG) module.

Background Art

[0002] A generally known SIP includes one or more anodes made as tubes or cylindrical openings, and a magnetic field is directed parallel to the central axis of the tube. The anode is surrounded by a cathode element. Specifically, the cathode element is arranged at a certain distance along the central axis opposite to the cylindrical opening of the anode. A strong electric field is generated between the anode and the cathode. The magnetic field expands the path of electrons in the anode cell, and gas atoms and molecules in the vacuum chamber are ionized. The resulting ions are accelerated and collide with the cathode element. When the accelerated ions collide with the cathode element, the ions are buried in the cathode material or sputter the cathode material onto other surfaces of the pump. The continuously sputtered chemically active cathode material functions as a getter, expelling gas by both chemisorption and physisorption, resulting in a net pumping action.

[0003] Conventionally, it is known to combine a SIP with a NEG pump. Usually, the NEG module includes a heating element and at least one, preferably a plurality of NEG elements arranged around the heating element. The NEG elements can be activated or reactivated during operation by heating with the heating element.

[0004] When SIP modules and NEG modules are combined, electrical connections of the heating elements are required. Wiring requires additional space, which is limited in a vacuum. However, passing electrical connections through the volume of the SIP has the disadvantage that the sputtered elements of the SIP module can reach the conductors of the NEG module, causing a short circuit between the SIP anode and the grounded components, shortening the lifespan of the SIP. Therefore, conventional technology typically uses separate arrangements of SIP modules and NEG modules, which increases the required space within the vacuum chamber. [Overview of the project] [Problems that the invention aims to solve]

[0005] The objective of this invention is to provide a compact vacuum pump that can operate reliably over a longer period of time. [Means for solving the problem]

[0006] This problem is solved by the vacuum pump described in claim 1.

[0007] The vacuum pump according to the present invention comprises a sputter ion pump (SIP) module having a first end and a second end. Furthermore, the vacuum pump comprises a non-evaporative getter (NEG) module coupled to the second end of the SIP module. Thus, the SIP module and the NEG module can be arranged in a stacked configuration to create a compact vacuum pump and inserted into the vacuum chamber of a vacuum apparatus having a reduced footprint. In detail, the NEG module can be directly coupled to the top of the SIP module. Alternatively, to facilitate coupling between the NEG module and the SIP module, the NEG module can also be coupled to the top of the SIP module via an intermediate element.

[0008] According to the present invention, the conductor of the NEG module extends from a first end to a second end of the SIP module. The SIP module comprises an anode having a first surface and a second surface on the opposite side, with at least one cylindrical opening extending from the first surface to the second surface. The cylindrical opening is considered the anode cell of the SIP module for the pumping action of the SIP module. The anode further comprises a side extending from the first surface to the second surface. The conductor of the NEG module extending from the first end to the second end of the SIP module is positioned on the side of the anode, preferably in direct contact with the side of the anode. Thus, the conductor is incorporated into the SIP module and routed through the SIP module, resulting in a small and compact vacuum pump. However, because the conductor is positioned on the side of the anode, the conductor is protected from sputtering by the SIP module. Thus, the anode itself shields the conductor from sputtering of the cathode element material of the SIP module onto or near the conductor. This reduces the possibility of a short circuit between the anode and grounded components of the SIP module by preventing sputtered metal from bridging the gap between the anode and grounded components via the conductor. In particular, the SIP module can operate for a longer period of time without failure.

[0009] Preferably, there is no line of sight between the cathode and the conductor of the SIP module, and more specifically, there is no line of sight between the projection of the anode onto the cathode and the conductor. It is not possible to draw a straight line from the diameter of the anode cell projected onto the cathode to the conductor without passing through another plane. This significantly reduces the possibility that the sputtered cathode material will coat the conductor with conductive material.

[0010] Preferably, the anode of the SIP module blocks the direct line of sight between the cathode and the conductor. Therefore, the anode itself blocks the line of sight between the cathode and the conductor.

[0011] Preferably, the anode of the SIP module has a width between 10 mm and 50 mm, more preferably between 15 mm and 30 mm, and most preferably between 15 mm and 20 mm, i.e., the distance from the first surface to the second surface, or the length of each anode cell. The width of the anode allows for sufficient shielding of the conductor so that the cathode material is not sputtered onto the conductor.

[0012] Preferably, the conductor is positioned to penetrate the SIP module. More specifically, the conductor is positioned to penetrate the SIP module or to penetrate the active volume or pumping volume of the SIP module. This allows for a compact design of the SIP module and the entire vacuum pump by integrating the conductor into the outer structure or pumping volume of the SIP module. This is possible because the conductor is shielded by the anode itself, reducing the possibility of sputtering material from the cathode of the SIP module onto the conductor.

[0013] Preferably, the conductor is surrounded by an insulator, preferably a ceramic insulator. The insulator allows direct contact between the conductor and the anode, so that the conductor can be positioned in direct contact with the anode without causing a short circuit.

[0014] Preferably, the conductor has at least two wires. More specifically, two wires are required because the conductor can connect the heating elements of the NEG module. Here, each wire can be surrounded by an insulator, preferably a ceramic insulator.

[0015] Preferably, the anode of the SIP module has at least one or more recesses, and the conductors are placed within these recesses. Here, in detail, the number of recesses is equal to the number of wires in the conductor. The recesses allow the conductors to be positioned closer to the anode, preventing a direct line of sight between the conductors and the cathode of the SIP module. At the same time, the structural stability of the conductors is also improved. This is important in detail when the conductors are surrounded by a brittle ceramic insulator and it is necessary to structurally stabilize the ceramic insulator.

[0016] Preferably, the outer structure of the SIP module and / or the outer structure of the NEG module is cylindrical. Here, in the case of the SIP module, the outer structure can be provided by a shell having a cylindrical shape. The outer structure can be a housing, which may or may not be vacuum-sealed. The housing provides a means for the SIP module and / or NEG module to function fully, preferably by coupling a vacuum pump to a vacuum device or vacuum chamber. Alternatively, the outer structure surrounds the elements of the SIP module and / or NEG module and is constructed to be inserted into a vacuum device or vacuum chamber. Here, the outer structure may have openings that allow gas to enter the SIP module or NEG module.

[0017] Preferably, the outer surfaces of the SIP module and the NEG module, and more specifically their respective outer structures, are flush with each other to provide the overall cylindrical shape of the vacuum pump.

[0018] Preferably, the vacuum pump has a flange, and the SIP module is coupled to the flange at its first end and preferably to the NEG module at its second end. More specifically, the SIP module is directly coupled to the flange by a base element, and the NEG module is coupled to the SIP module via an upper element of the SIP module. Alternatively, the base element may be a flange for coupling the SIP module / NEG module to a vacuum device or vacuum chamber.

[0019] Preferably, the SIP module and NEG module are positioned within the flange area. Thus, the SIP module and NEG module can be inserted together into the vacuum chamber and secured to the vacuum chamber by the flange.

[0020] Preferably, the NEG module and the SIP module are arranged entirely within a vacuum. Specifically, due to the small construction size of the NEG module and the SIP module, both can be inserted into the vacuum chamber and coupled to the vacuum chamber by flanges. Therefore, the volume of additional vacuum space is not added to the vacuum chamber in which the vacuum pump is installed. At the same time, according to the present invention, the number of components in the vacuum is reduced compared to the case where the design of a standard ion pump is modified to be attached to the flange.

[0021] Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

Brief Description of the Drawings

[0022] [Figure 1] A vacuum pump according to the present invention. [Figure 2] A cross-sectional view of the vacuum pump of FIG. 1. [Figure 3] The frame structure of the vacuum pump of FIG. 1. [Figure 4A] The frame structure and anode of the vacuum pump of FIG. 1. [Figure 4B] The frame structure and anode of the vacuum pump of FIG. 1. [Figure 5A] The shell element of the vacuum pump of FIG. 1. [Figure 5B] The shell element of the vacuum pump of FIG. 1. [Figure 5C] The shell element of the vacuum pump of FIG. 1. [Figure 6A] A cross-sectional view of the non-evaporable getter module. [Figure 6B] A cross-sectional view of the non-evaporable getter module. [Figure 7] A connection element according to the present invention. [Figure 8A] A heat insulation element according to the present invention. [Figure 8B] A heat insulation element according to the present invention. [Figure 9] A cross-sectional view of the SIP module according to FIG. 1. [Modes for carrying out the invention]

[0023] Referring to Figure 1, a vacuum pump 10 according to the present invention is shown. Here, the vacuum pump 10 comprises a non-evaporative getter (NEG) module 12, a sputter ion pump (SIP) module 14, and a vacuum flange 16. Here, the SIP module 14 is directly coupled to the flange 16, and the NEG module 12 is attached to the SIP module 14 on the opposite side of the flange 16. The vacuum pump 10, in particular both the NEG module 12 and the SIP module 14, have a cylindrical shape. The shape of the SIP module 14 closely matches the shape of the NEG module 12, so that the SIP module 14 and the NEG module 12 have substantially similar or identical external shapes or, finally, cross-sections. In the following figures, the vacuum pump has a cylindrical shape, but other shapes are also possible.

[0024] The NEG module 12 and SIP module 14 are positioned within the area of ​​the flange 16 and can be fully inserted into the vacuum chamber for pumping.

[0025] Refer to Figure 2. In the cross-sectional view, the SIP module 14 is shown to have an anode 20, and in the example of Figure 2, it has three cylindrical openings or tubes. Any other number of tubes is also possible. Cathodes 18 are located at the axial ends of these openings. The anode 20 is guided through the flange by a vacuum feedthrough 26 and is maintained at a high potential by a high-voltage (HV) conductor 28 connected to the anode. Furthermore, the flange 16 is provided with a connector 68 which is connected to a heating element 32 of the NEG module 12 via a conductor 30. The NEG element 34 is positioned on the heating element 32 to reactivate the NEG material by heating.

[0026] Here and below, the axial direction of the SIP and its elements is defined along the anode from its bottom to its top. Here and below, the transverse direction refers to the direction perpendicular to the axial direction of the anode.

[0027] Refer to Figure 3, which shows the frame structure 48 of the SIP module. The frame structure 48 comprises a base element 50 that can be attached to the flange 16 by welding, brazing, soldering, screws, or some other releaseable coupling means. In other embodiments, the flange 16 and the base element 50 may be made integrally, or the base element 50 may be provided by the flange 16 itself. In the example in Figure 3, two frame side elements 24, made as shouldered screws or struts extending from the base element 50 to the upper element 52, are coupled to the base element 50. The NEG module 12 can be coupled to the upper element 52 by welding, brazing, soldering, screws, or some other releaseable coupling means. During assembly, the anode 20 is fixed within the frame structure 48, and then the frame structure 48 is coupled to the flange 16 together with the anode 20. This is shown in Figures 4A and 4B. The anode 20 is coupled within the frame structure 48 by a lower support element 71 provided by an insulating element 62 coupled to the anode 20. Furthermore, the upper support element 73 is provided by an insulating element 74, where the insulating elements 62 and 74 are made of an insulating material such as ceramic material. The lower insulating support 71 restricts the anode 20 from downward movement toward the flange 16 and can also restrict lateral movement, i.e., movement in one or more other directions or all other directions. The upper support element 73 restricts the anode 20 from upward movement and lateral movement, i.e., movement in one or more other directions or all other directions. At least one support element 71, 73 or two support elements 71, 73 may not completely restrict lateral movement while connecting the anode to the HV conductor 28, allowing slight lateral movement of the anode to facilitate attachment of the HV conductor 28 to the anode 20. Thus, a secure connection between the HV conductor 28 and the anode 20 is possible, and slight manufacturing deviations can be compensated for. To completely prevent the anode 20 from moving and to fix the anode's position within the frame structure, the anode 20 is coupled to an HV conductor 28 extending through an opening in the base element 50 via a conductive sleeve 49 that couples the anode 20 to the HV conductor 28 of the vacuum feedthrough 26.Therefore, the anode 20 is fixed in place within the frame structure 48 of the SIP module 14 by the coupling of the lower support element 71, the upper support element 73, and the electrical feedthrough 26 to the HV conductor 28.

[0028] Therefore, the steps for assembling the SIP module 14 are: a) A step of providing a frame structure preferably comprising a base element 50, one or more frame side elements 24 coupled to the base element, and upper elements 52 coupled to each frame side element 24, b) Inserting the anode and connecting the anode to the frame structure by the lower support element 71 and the upper support element 73, c) The step of attaching the frame structure 48 together with the anode 20 to the flange 16, thereby coupling the anode 20 to the electrical feedthrough 26 and at the same time fixing the position of the anode 20 within the SIP module 14. d) The step of attaching the shell around the frame structure 48, as will be described in detail below. Includes.

[0029] Refer to Figures 5A-5C, which show details of the shell of the vacuum pump 10. The shell of the vacuum pump 10, more specifically the shell of the SIP module 14, comprises two separate shell elements 22. Here, each shell element 22 is made identically in this embodiment, but the shell elements 22 can also be made / designed differently. Each shell element 22 comprises at least one magnet 78, and in the example of Figures 5A-5C, each shell element 22 comprises two magnets 78. Here, the magnets 78 are positioned in recesses 79 of the shell element 22 to prevent lateral movement. The size of the recesses 79 is adapted to the size of the magnets such that the side walls of the recesses 79 are in direct contact with the side walls of each magnet 78. The magnets 78 are attached to each shell element 22 solely by their magnetic force. There are no further fixing / fastening elements. Thus, the shell elements 22 serve as both the magnetic pole pieces and the outer structure of the SIP module 14. The pole pieces guide the magnetic flux through the SIP module 14, and the outer structure provides structural stability to the SIP module 14. Therefore, the shell element 22 is made of a magnetic material such as mild steel. The magnet 78 is a neodymium (Nd) magnet or a samarium (Sa) cobalt (Co) magnet. One surface of the magnet is attached to the shell element 22. The opposite surface of the magnet 78 is directly coupled to the cathode 18. The cathode 18 is plate-like and covers all or substantially all of the surface of the magnet 78. The cathode 18 can be made of titanium (Ti) or tantalum (Ta). Two shell elements 22 may have cathode elements 18, 18' made of the same or different materials. Bracket or clamp elements 80 are provided at the upper and lower ends of each magnet 78 to fix the cathode 18 in place. The bracket elements 80 are held in place by the magnetic force of the magnet 78. No additional fixing elements are required. The bracket element 80 has a chamfered surface 84, which includes a chamfered portion facing the magnet 78. Similarly, the cathode element 18 has a chamfered portion facing outward from the magnet 78, and a chamfered edge 82 that corresponds to the chamfered surface 84 of the bracket element 80. When the bracket element 80 is attached to the side of the magnet 78, a clamping force is applied to the cathode 18 to fix its position.Since the surface of the cathode element 18 is flush with each bracket element 80, the cathode element 18 can be positioned closely with respect to the anode 20. Furthermore, the anode element 18 can be assembled and disassembled without the need for additional tools.

[0030] The two shell elements 22 are similar in shape to the SIP module 14. The shell elements 22 have openings 23 that allow gas molecules and particles to enter the active volume of the SIP module. The present invention is not limited by the number or shape of these openings 23. To ensure sufficient stability of the shell elements, the shell elements 22 are provided with recesses 81 along the axial direction of the shell elements 22 at their axial ends, which accommodate the frame side elements 24 when attached to the shell elements 22. Thus, the position of the shell elements 22 is determined by the position of the frame side elements 24, by the corresponding shape of the recesses 81.

[0031] Refer to Figures 6A and 6B, which show an NEG module 12 comprising a heater 32 having a heating wire 86. The NEG module 12 comprises a base element 88 and an upper element 90, and the NEG element 34 is sleeved over the heater 32. The upper element 90 and the base element 88 can be connected by NEG side elements such as shouldered screws or struts. In detail, the NEG side elements are made of threaded rods or struts. Electrical connection of the heater 32 is provided by an electrical connector 38 having a connecting element 94. The connecting element 94 is shown in detail in Figure 7. The connecting element 94 comprises a first end 96 and a second end 98. Between the first end 96 and the second end 98, there is a collar or protruding feature 100. Although Figure 7 shows that the first end 96 and the second end 98 may have the same diameter, the present invention is not limited to this example, and different diameters of the first end 96 and the second end 98 are also possible. Similarly, while the example in Figure 7 shows a circular cross-section, other shapes are, of course, also possible.

[0032] As shown in Figures 8A and 8B, the connector 38 comprises insulating elements 102 and 106. The first insulating element 102 has an opening 104, where the number of openings 104 corresponds to the number of connecting elements 94. The diameter of the opening 104 corresponds to the diameter of the first end 96, and preferably the insulating element 102 is made of ceramic material. Similarly, the second insulating element 106 is made of ceramic material. The second insulating element 106 is made of two halves, although Figure 8B shows only a single half. The two halves of the insulating element 106 define an opening 108, where the diameter of the opening 108 corresponds to the diameter of the second end 98 of the connecting element 94. The connecting element 94 is crimped to the heating wire 86 of the heater 32 or otherwise attached. The two halves of the second insulating element are then inserted into the housing of the base element 88 of the NEG module 12 and seated on the shoulder portion 95. Here, the protruding feature 100 prevents the connecting element 94 from falling through the opening 108 of the second insulating element 106. The first insulating element 102 is then assembled by inserting the first end 96 of the connecting element 94 into the respective openings 104. The protruding feature 100 prevents the connecting element 94 from falling out of the first insulating element 102. The first insulating element 102 and the second insulating element 106 are fixed in place by a fixing element, for example, provided by a set screw. This prevents clamping force from directly acting on the connecting element 94. The protruding feature 100 fixes the fixing element 94 in its axial position, while slight lateral movement of the connecting element 94 is still permitted, which is useful when assembling the NEG module 12.

[0033] Similar to the connector 38 that connects the NEG module 12 to the SIP module 14, a connector 40 is provided to connect the SIP module to the flange 16, as shown in Figures 4A and 4B. This allows the conductor 30 connected to the heater 32 to pass completely through the flange 16 to the SIP module 14 and then to the NEG module 12 via the connector 38. The conductor 30 may include two electrical wires 110, 110' surrounded by an insulating material such as ceramic.

[0034] The following refers to Figure 9, which shows a cross-sectional top view of the SIP module 14. The anode 20 has a first surface 114 and a second surface 118 on the opposite side, which correspond axially to the cylindrical opening of the anode 20. The first surface 114 and the second surface 118 are joined by a side surface 116, and the conductor 30 extends along the side surface 116 of the anode 20. Due to the position of the conductor 30, there is no direct line or line of sight 112 between the cathode element 18 and the conductor 30, thus preventing or at least reducing the possibility of sputtering the cathode material onto the surface of the conductor 30, which could cause a short circuit. Thus, the conductor 30 is protected by the anode 20 itself. Accordingly, the side surface 116 of the anode can be provided with recesses 120 for accommodating the conductor 30 and the respective wires 110, 110' of the conductor 30. Therefore, the low-voltage supply to the heater 32 of the NEG module 12 is provided from the connector 68 through the connecting element 40 and the conductor 30 across the SIP module 14, more specifically through the magnetic pole piece of the SIP module provided by the shell element 22, toward the connector 38 of the upper element 52 of the SIP module, and further toward the connector 38 and the heater 32.

[0035] Accordingly, the vacuum pump according to the present invention provides a combination of NEG modules and SIP modules, both of which can be fully inserted into a vacuum chamber with a small cross-sectional area. At the same time, the mounting of the frame structure 48 and shell simplifies the assembly process of the SIP module 14 and reduces the number of parts required in vacuum. [Explanation of Symbols]

[0036] 10 Vacuum pump 12 NEG modules 14 SIP Modules 16 flange 18, 18' Cathode element 20 Anode 22 Shell Elements 23 Opening 24 Frame side elements 26 Vacuum feedthrough 28 HV conductor 30 conductor 32 heating element 34 NEG elements 38 connectors 40 connectors 48 Frame Structure 49 Conductive sleeve 50 Base elements 52 Top element 62 Insulating elements 68 connectors 71 Lower support element 73 Upper support element 74 Insulating elements 78 Magnets 79 Recess 80 Bracket Elements 81. Indentation 82 Chamfered edge 84 Chamfered surface 86 Heating wire 88 Base element 90 Top element 94 connection elements 95 Shoulder 96 First end 97 Fixed elements 98 Second end 100 Protruding feature 102 First insulating element 104 Opening 106 Second insulating element 108 Opening 110, 110' wire 112 Line of sight 114 First surface 116 Side view 118 Second surface 120 indentations

Claims

1. A sputter ion pump (SIP) module having a first end and a second end, A non-evaporative getter (NEG) module coupled to the second end of the SIP module, The conductors of the NEG module extend from the first end to the second end of the SIP module, A vacuum pump equipped with, The SIP module comprises an anode having a first surface and a second surface on the opposite side, with at least one cylindrical opening extending from the first surface to the second surface, and the anode further comprising a side extending from the first surface to the second surface. The aforementioned wire is positioned on the side surface of the anode of the vacuum pump.

2. The vacuum pump according to claim 1, wherein there is no line of sight between the cathode of the SIP module and the conductor, more specifically between the projection of the anode onto the cathode and the conductor.

3. The vacuum pump according to claim 1 or 2, wherein the anode of the SIP module blocks the direct line of sight between the cathode and the conductor.

4. The vacuum pump according to any one of claims 1 to 3, wherein the width of the anode of the SIP module is between 10 mm and 50 mm, more preferably between 15 mm and 30 mm, and most preferably between 15 mm and 20 mm.

5. The vacuum pump according to any one of claims 1 to 4, wherein the aforementioned conductor is located within the SIP module.

6. The vacuum pump according to any one of claims 1 to 5, wherein the conductor is surrounded by an insulator, preferably a ceramic insulator.

7. The vacuum pump according to any one of claims 1 to 6, wherein the conductor has at least two electric wires.

8. The vacuum pump according to any one of claims 1 to 7, wherein the anode of the SIP module has at least one or more recesses, and the conductors are arranged in the recesses.

9. The vacuum pump according to any one of claims 1 to 8, wherein the outer structure of the SIP module and / or the outer structure of the NEG module is cylindrical.

10. The vacuum pump according to any one of claims 1 to 9, wherein the outer surface of the SIP module and the outer surface of the NEG module are flush with each other.

11. The vacuum pump according to any one of claims 1 to 10, wherein the vacuum pump comprises a flange, the SIP module is coupled to the flange at its first end, and / or the NEG module and the SIP module are arranged within the area of ​​the flange.

12. The vacuum pump according to any one of claims 1 to 11, wherein the NEG module and / or the SIP module are located in a complete vacuum.

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