Radio frequency coupling plasma source applied to positive pressure environment

Abstract

The invention relates to the technical field of plasma sources, in particular to a radio frequency coupling plasma source applied to a positive pressure environment. According to the technical scheme, the ion source comprises a gas source and an ion source gas inlet connector connected with the gas source; the ion source chamber is connected with the ion source air inlet interface, a first connecting assembly is fixed between the ion source air inlet interface and the ion source chamber, and an ion sputtering baffle is fixedly installed in the bottom of the ion source chamber; the radio frequency power supply is arranged on one side of the ion source chamber, and a coil is arranged between the ion source chamber and the radio frequency power supply; and the supporting mechanism is used for supporting the ion source chamber. The use requirement of the ion source in the positive pressure environment can be met, the influence of the external pressure gas environment on the source is avoided, the use condition of the ion source in the external positive pressure environment is met, the requirement that the plasma cavity of the radio frequency coupling plasma source needs to be frequently replaced is met, the cost is low, and maintenance and replacement are convenient.

Description

Technical Field

[0001] The present invention relates to the technical field of plasma sources, and in particular to a radio frequency coupled plasma source used in a positive pressure environment. Background Art

[0002] Neutron activation method based on small accelerator neutron source 98 Mo(n,γ) 99 Mo reaction preparation 99 Mo's solution involves a 1.5MV UHV power supply. Since the atmospheric insulation level cannot meet the insulation requirements of the UHV power supply, the power supply itself and the corresponding MV-level ion source accelerator system should be placed inside a closed cavity filled with SF6 gas. The pressure of SF6 inside the cavity is determined by the required voltage of the MV-level ion source accelerator system. The maximum voltage is 1.5MV, and the SF6 pressure needs to reach 0.6MPa. Therefore, the structure of the RF-coupled ion source needs to be optimized to meet the needs of the positive pressure environment outside. The RF-coupled plasma source usually uses a ceramic tube or a glass tube as an excitation chamber, and the two ends of the chamber are sealed in a vacuum by combining a metal cover plate and an rubber ring. This structure can be used normally in an atmospheric environment, and the system leakage rate meets the requirements; when the external environment is replaced with a pressurized gas, the leakage rate that originally meets the requirements will gradually increase, and the external gas will penetrate into the interior of the ion source chamber through the sealing rubber ring, so that there is impurity gas inside the ion source, which pollutes the beam. To solve the problem of ion source leakage under an external pressure environment. The present application proposes a RF-coupled plasma source for use in a positive pressure environment. Summary of the invention

[0003] The purpose of the present invention is to solve the problem of ion source leakage in an external pressure environment in the background technology, and to propose a radio frequency coupled plasma source for use in a positive pressure environment.

[0004] The technical solution of the present invention: a radio frequency coupled plasma source applied in a positive pressure environment, comprising a gas source and an ion source gas inlet interface connected to the gas source;

[0005] An ion source chamber connected to the ion source air inlet interface, a connecting component 1 is fixed between the ion source air inlet interface and the ion source chamber, and an ion sputtering baffle is fixedly installed in the bottom of the ion source chamber;

[0006] A radio frequency power supply is arranged at one side of the ion source chamber, and a coil is installed between the ion source chamber and the radio frequency power supply;

[0007] A supporting mechanism is used to support the ion source chamber, and a connecting component 2 is installed between the supporting mechanism and the bottom of the ion source chamber.

[0008] Optionally, the connecting component 1 includes an ion source upper sealing cover plate 1 pressed against the top of the ion source chamber, the bottom of the ion source air inlet interface passes through the ion source upper sealing cover plate 1, the top fixed sleeve of the ion source chamber is provided with an ion source upper sealing cover 2 located below the ion source upper sealing cover plate 1, the ion source upper sealing cover 2 is connected to the ion source upper sealing cover plate 1 by a sealing screw 1, and the top sleeve of the ion source chamber is provided with an O-ring located between the ion source upper sealing cover plate 1 and the ion source upper sealing cover 2.

[0009] Optionally, a rectangular groove is provided at the bottom of the sealing cover plate 1 on the ion source, the top of the ion source chamber is fixedly connected to the inner wall of the rectangular groove, and a rectangular rubber ring located at the top of the ion source chamber is installed in the rectangular groove.

[0010] Optionally, the second connecting component includes an ion source lower sealing plate 1 pressed against the supporting mechanism, and the bottom fixed sleeve of the ion source chamber is provided with an ion source lower sealing plate 2, and the ion source lower sealing plate 1 and the ion source lower sealing plate 2 are connected by a sealing screw 2.

[0011] Optionally, an insulating screw is fixedly installed on the top of the lower sealing plate 1 of the ion source, and the top of the insulating screw slides through the upper sealing cover plate 1 of the ion source and is threadedly sleeved with a sealing nut 1 that presses against the upper sealing cover plate 1 of the ion source.

[0012] Optionally, the supporting mechanism is installed on the PG electrode base at the bottom of the ion source lower sealing plate 1, and the bottom of the PG electrode base is fixedly installed with an insulating support 1, and the bottom of the insulating support 1 is fixedly installed with an EG electrode base, an insulating support 2 and a GG electrode base connected in sequence.

[0013] Optionally, a sealing bolt is threadedly installed on the lower sealing plate 1 of the ion source, the sealing bolt thread penetrates the PG electrode base and is threadedly connected with a sealing nut 2, and the sealing nut 2 abuts against the bottom of the PG electrode base.

[0014] Optionally, a metal sealing ring is installed between the lower sealing plate 1 of the ion source and the PG electrode base.

[0015] Compared with the prior art, the present invention has at least one of the following beneficial technical effects:

[0016] The present invention provides a radio frequency coupled plasma source for use in an external positive pressure environment, which can meet the use requirements of the ion source in a positive pressure environment and avoid the influence of the external pressure gas environment on the source.

[0017] The present invention adopts multiple rubber ring sealing to seal the plasma chamber, which not only meets the use conditions of the ion source in an external positive pressure environment, but also meets the demand of frequent replacement of the plasma chamber of the radio frequency coupled plasma source. Compared with welding sealing, the plasma chamber sealed with multiple rubber rings can be used repeatedly, reducing costs.

[0018] The RF coupled plasma source designed in the present invention has a high degree of modularization, and almost all components can be replaced individually, which is convenient for maintenance. The reserved electrode base can meet the needs of replacing electrodes of different structures, and the electrode can be replaced in time when the electrode structure cannot meet the requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the structure of a radio frequency coupled plasma source used in a positive pressure environment;

[0020] Figure 2 It is a schematic diagram of the connection structure between the sealing cover plate 1 on the ion source and the ion source chamber.

[0021] Figure numerals: 1. ion source air inlet interface; 2. insulating screw; 3. sealing nut one; 4. rectangular rubber ring; 5. ion source upper sealing cover one; 6. O-ring; 7. sealing screw one; 8. ion source upper sealing cover two; 9. ion source chamber; 10. gas source; 11. RF power supply; 12. coil; 13. ion sputtering baffle; 14. ion source lower sealing plate two; 15. sealing bolt; 16. ion source lower sealing plate one; 17. metal sealing ring; 18. PG electrode base; 19. sealing nut two; 20. insulating support one; 21. EG electrode base; 22. insulating support two; 23. GG electrode base. DETAILED DESCRIPTION

[0022] The technical solution of the present disclosure will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present disclosure, rather than all of the embodiments.

[0023] The components of the embodiments of the present disclosure generally described and shown in the drawings herein may be arranged and designed in a variety of different configurations. Therefore, the following detailed description of the embodiments of the present disclosure provided in the drawings is not intended to limit the scope of the present disclosure claimed, but merely represents selected embodiments of the present disclosure.

[0024] Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in the field without making any creative work shall fall within the scope of protection of the present disclosure.

[0025] Example

[0026] like Figure 1As shown, the present invention proposes a radio frequency coupled plasma source for use in a positive pressure environment, including a gas source 10 and an ion source gas inlet interface 1 connected to the gas source 10, the ion source gas inlet interface 1 conveys a gas flow, the gas source 10 is a working gas of the radio frequency coupled plasma source, and the gas type is selected from hydrogen or deuterium according to the target ions to be drawn out by the system design. The designed radio frequency coupled plasma source can directly replace the gas source without replacing other equipment, and excite and generate other types of plasma, thereby drawing out the required ions.

[0027] An ion source chamber 9 is connected to the bottom of the ion source air inlet interface 1, a connecting component 1 is fixed between the ion source air inlet interface 1 and the ion source chamber 9, the connecting component 1 includes an ion source upper sealing cover plate 5 pressed against the top of the ion source chamber 9, the bottom of the ion source air inlet interface 1 passes through the ion source upper sealing cover plate 5, the ion source air inlet interface 1 is composed of a standard 1 / 4 inch steel pipe welded on the ion source upper sealing cover plate 1, and a standard 1 / 4 inch ferrule interface is used to dock and seal with other pipelines, the top of the ion source chamber 9 is fixedly sleeved with an ion source upper sealing cover 2 8 located below the ion source upper sealing cover plate 1 5, the ion source upper sealing cover 2 8 is connected to the ion source upper sealing cover plate 5 by a sealing screw 7, and the top of the ion source chamber 9 is sleeved with an O-ring 6 located between the ion source upper sealing cover plate 5 and the ion source upper sealing cover 2 8;

[0028] Among them, a rectangular groove is provided at the bottom of the sealing cover plate 5 on the ion source, the top of the ion source chamber 9 is fixedly connected to the inner wall of the rectangular groove, a rectangular rubber ring 4 located at the top of the ion source chamber 9 is installed in the rectangular groove, the sealing cover plate 5 on the ion source is a metal flange, the material of which is the common 304 stainless steel, and its main function is to cooperate with the rectangular rubber ring 4 to seal the upper end of the ion source chamber 9, which is the main seal of the upper end of the ion source chamber 9, the rectangular rubber ring 4 is a ring-shaped rectangular gasket made of rubber material, and the material is fluororubber, which is formed or processed. The rectangular rubber ring 4 is made of fluororubber material, which has the advantages of high temperature resistance, corrosion resistance and good stability. An ion sputtering baffle 13 is fixedly installed in the bottom of the ion source chamber 9, and the ion sputtering baffle 13 mainly functions to reduce the sputtering ions generated by the collision between the plasma and the extraction electrode to contaminate the ion source chamber 9, and the material of the ion sputtering baffle 13 can be selected from quartz or other materials with low secondary electron emission coefficient.

[0029] In this embodiment, a radio frequency power supply 11 is provided on one side of the ion source chamber 9, and a coil 12 is installed between the ion source chamber 9 and the radio frequency power supply 11; the radio frequency power supply 11 is a radio frequency power supply and automatic matcher of common frequency on the market, and the radio frequency power supply selects 13.56MHz or 1MHz according to the design requirements of the radio frequency coupled plasma source, and the power selects 300-1000W. The interface reserved for the radio frequency coupled plasma source system design radio frequency power supply 11 has good compatibility, and radio frequency power supplies of different powers and frequencies can be replaced at any time according to system requirements to meet different system requirements. The ion source chamber 9 is the main excitation chamber of the radio frequency coupled plasma. The material of the ion source chamber 9 is quartz or ceramic, and the shape is usually cylindrical. The coil is wound around the outside of the ion source chamber 9, and the radio frequency power supply couples the power to the excitation ion source chamber 9 through the coil 12, ionizing the gas into plasma.

[0030] The coil 12 is a multi-turn copper tube wrapped around the ion source chamber 9, and the two ends of the copper tube are connected to the RF power supply matcher to couple the RF power into the ion source chamber 9 to ionize the gas into plasma. The outer diameter of the copper tube is selected to be 3-8 mm according to the system requirements, and the number of winding turns is 5-10 turns.

[0031] A supporting mechanism for supporting the ion source chamber 9 is provided, and a connecting assembly 2 is installed between the supporting mechanism and the bottom of the ion source chamber 9. The connecting assembly 2 includes an ion source lower sealing plate 16 pressed against the supporting mechanism. The bottom of the ion source chamber 9 is fixedly sleeved with an ion source lower sealing plate 2 14. The ion source lower sealing plate 16 is connected to the ion source lower sealing plate 2 14 by a sealing screw 2. The ion source lower sealing plate 2 14 is a metal flange, and the material is selected as 304 stainless steel. It is smaller in size than the ion source upper sealing cover plate 1 5. Its main function is to cooperate with the O-ring 6 to perform secondary sealing on the radial surface of the ion source chamber 9 to reduce the infiltration of external gas into the ion source chamber 9.

[0032] It is worth noting that an insulating screw 2 is fixedly installed on the top of the ion source lower sealing plate 16, and the top of the insulating screw 2 slides through the ion source upper sealing cover plate 5 and is threadedly sleeved with a sealing nut 3 pressed against the ion source upper sealing cover plate 5. The insulating screw 2 and the sealing nut 3 ensure the stability of the connection between the ion source upper sealing cover plate 5, the ion source chamber 9 and the ion source lower sealing plate 16. The ion source lower sealing plate 16 is a metal flange, which is mainly used to cooperate with the rectangular rubber ring 4 to perform end face sealing on the lower end of the ion source chamber 9, and is the main seal for sealing the lower end of the ion source chamber 9. At the same time, it provides a support and installation platform for the ion sputtering baffle 13.

[0033] Furthermore, the insulating screw 2 is the main tensioning function of the ion source upper sealing cover plate 5 and the ion source lower sealing plate 16. The ion source upper sealing cover plate 5 and the rectangular rubber ring 4 are pressed by the insulating screw 2, thereby sealing the ion source chamber 9. The ion source lower sealing plate 16 is processed with a threaded hole for installing the insulating screw 2. The material of the insulating screw 2 is selected from PEEK and polyoxymethylene with low conductivity, and it is also required to have a certain mechanical strength to prevent the sealing nut from collapsing, causing vacuum rupture, and damaging other equipment.

[0034] The supporting mechanism is installed on the PG electrode base 18 at the bottom of the ion source lower sealing plate 16. The bottom of the PG electrode base 18 is fixedly installed with an insulating support 20. The bottom of the insulating support 20 is fixedly installed with an EG electrode base 21, an insulating support 22 and a GG electrode base 23 connected in sequence.

[0035] A sealing bolt 15 is threadedly installed on the lower sealing plate 16 of the ion source. The sealing bolt 15 threadably penetrates the PG electrode base 18 and is threadedly connected to a sealing nut 2 19. The sealing nut 2 19 abuts against the bottom of the PG electrode base 18 to achieve the connection between the lower sealing plate 16 of the ion source and the PG electrode base 18.

[0036] Among them, a metal sealing ring 17 is installed between the lower sealing plate 16 of the ion source and the PG electrode base 18. The metal sealing ring 17 is a vacuum sealing medium between the lower sealing plate 16 of the ion source and the PG electrode base 18. The material is usually oxygen-free copper, silver wire, indium wire, and metal materials with low hardness, and is made into different shapes according to the sealing structure. The sealing bolt 15 and the sealing nut 19 are used to press the lower sealing plate 16 of the ion source and the PG electrode base 18, causing the metal sealing ring 17 to deform and fit closely to the interface between the lower sealing plate 16 of the ion source and the PG electrode base 18, thereby achieving vacuum pressure sealing.

[0037] In this embodiment, the PG electrode base 18 is used to provide a fixed and leveled mounting surface for the PG electrode, and the material is selected from 304 stainless steel or Kovar alloy. One side of the PG electrode base 18 is reserved with a vacuum sealing interface with the ion source lower sealing plate 16, which adopts a metal sealing form; the other side is bonded or welded with the insulating support 20. Both the upper and lower sealing surfaces of the PG electrode base 18 can be unaffected by the external environmental pressure, and the leakage rate always meets the experimental requirements.

[0038] Among them, the insulating support 1 20 is an insulating support between the PG electrode base 18 and the EG electrode base 21, and seals and connects the PG electrode base 18 and the EG electrode base 21. The material is selected from PEEK, epoxy, and ceramic materials with high dielectric constants. The bonding or welding method is selected according to the materials of the insulating support 1 20 and the upper and lower electrode bases to ensure that the leakage rate at the sealing surface meets the requirements.

[0039] In this embodiment, the EG electrode base 21 is a metal flange, which serves to provide a fixed and leveled mounting surface for the EG electrode, and the material is usually 304 stainless steel or valveable metal material. The flange of the EG electrode base 21 is sealed with the insulating support 1 20 and the insulating support 2 22 on both sides, and the sealing is performed by bonding or welding according to the material, and the sealing part needs to be able to maintain the leakage rate required for the experiment under a certain pressure.

[0040] It should be noted that the insulating support 22 is an insulating support between the EG electrode base 21 and the GG electrode base 23, connecting the EG electrode base 21 and the GG electrode base 23. The material is usually selected from PEEK, epoxy, and ceramic materials with high dielectric constants. The insulating support 22 and the EG electrode base 21 and the GG electrode base 23 must have a certain vacuum pressure sealing ability, and the sealing form of bonding or welding is selected according to the material. The sealing part needs to maintain a certain sealing ability under the external pressure environment, and the leakage rate of the sealing part meets the experimental requirements.

[0041] In this embodiment, the GG electrode base 23 is a metal flange, which serves to provide a fixed and leveled mounting surface for the GG electrode. The material is usually 304 stainless steel or valveable metal material. At the same time, one side of the GG electrode base 23 needs to be vacuum-pressure-sealed with the insulating support 22. Adhesion or welding is usually selected according to the upper and lower materials; the other side has a metal vacuum-sealed interface with the ion transmission channel. Screws and nuts are used to tighten the metal vacuum-sealed flange between the GG electrode base and the ion transmission channel (the GG electrode base is the docking interface between the radio frequency coupled plasma source and the ion transmission pipeline. The ion transmission pipeline is a universal device and is not shown in the figure), causing the metal sealing ring to deform and fit tightly with the upper and lower flange interfaces, thereby achieving vacuum pressure sealing.

[0042] The above specific embodiments are only several optional embodiments of the present invention. Based on the technical solutions of the present invention and the relevant inspirations of the above embodiments, those skilled in the art can make various alternative improvements and combinations to the above specific embodiments.

Claims

1. A radio frequency coupled plasma source used in a positive pressure environment, characterized in that: include: A gas source (10) and an ion source gas inlet interface (1) connected to the gas source (10); An ion source chamber (9) connected to the ion source air inlet interface (1), a connecting component 1 being fixed between the ion source air inlet interface (1) and the ion source chamber (9), and an ion sputtering baffle (13) being fixedly installed in the bottom of the ion source chamber (9); A radio frequency power supply (11) is arranged on one side of the ion source chamber (9), and a coil (12) is installed between the ion source chamber (9) and the radio frequency power supply (11); A supporting mechanism is used to support the ion source chamber (9), and a second connecting component is installed between the supporting mechanism and the bottom of the ion source chamber (9).

2. The radio frequency coupled plasma source used in a positive pressure environment according to claim 1, characterized in that: The connecting component 1 comprises an ion source upper sealing cover plate 1 (5) pressed against the top of the ion source chamber (9); the bottom of the ion source air inlet interface (1) passes through the ion source upper sealing cover plate 1 (5); the top fixed sleeve of the ion source chamber (9) is provided with an ion source upper sealing cover 2 (8) located below the ion source upper sealing cover plate 1 (5); the ion source upper sealing cover 2 (8) is connected to the ion source upper sealing cover plate 1 (5) by a sealing screw 1 (7); and the top sleeve of the ion source chamber (9) is provided with an O-ring (6) located between the ion source upper sealing cover plate 1 (5) and the ion source upper sealing cover 2 (8).

3. The radio frequency coupled plasma source used in a positive pressure environment according to claim 2, characterized in that: A rectangular groove is provided at the bottom of the sealing cover plate (5) on the ion source, the top of the ion source chamber (9) is fixedly connected to the inner wall of the rectangular groove, and a rectangular rubber ring (4) located at the top of the ion source chamber (9) is installed in the rectangular groove.

4. The radio frequency coupled plasma source used in a positive pressure environment according to claim 1, characterized in that: The second connecting component comprises an ion source lower sealing plate 1 (16) pressed against the supporting mechanism, and the bottom fixed sleeve of the ion source chamber (9) is provided with an ion source lower sealing plate 2 (14), and the ion source lower sealing plate 1 (16) and the ion source lower sealing plate 2 (14) are connected by a sealing screw 2.

5. The radio frequency coupled plasma source used in a positive pressure environment according to claim 4, characterized in that: An insulating screw (2) is fixedly mounted on the top of the ion source lower sealing plate (16); the top of the insulating screw (2) slides through the ion source upper sealing cover plate (5) and is threadedly sleeved with a sealing nut (3) pressed against the ion source upper sealing cover plate (5).

6. The radio frequency coupled plasma source used in a positive pressure environment according to claim 4, characterized in that: The support mechanism is installed on a PG electrode base (18) at the bottom of the ion source lower sealing plate 1 (16), and an insulating support 1 (20) is fixedly installed at the bottom of the PG electrode base (18), and an EG electrode base (21), an insulating support 2 (22) and a GG electrode base (23) which are connected in sequence are fixedly installed at the bottom of the insulating support 1 (20).

7. The radio frequency coupled plasma source used in a positive pressure environment according to claim 5, characterized in that: A sealing bolt (15) is threadedly installed on the lower sealing plate (16) of the ion source. The sealing bolt (15) threadably penetrates the PG electrode base (18) and is threadedly connected to a sealing nut (19). The sealing nut (19) abuts against the bottom of the PG electrode base (18).

8. The radio frequency coupled plasma source used in a positive pressure environment according to claim 7, characterized in that: A metal sealing ring (17) is installed between the ion source lower sealing plate (16) and the PG electrode base (18).

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