Electron Cyclotron Resonance Ion Source

Abstract

The application discloses an electron cyclotron resonance ion source, which comprises a plurality of microwave transmission modules, a plurality of microwave resonance cavities, a plasma generation chamber and a magnetic field module, the microwave transmission module comprises a microwave source, an impedance matcher and a waveguide, the microwave source is used for generating and emitting microwaves, the microwave sources generate microwaves with the same or different frequencies, the inlet of the waveguide is connected with the microwave source, and the outlet is connected with the microwave resonance cavity, each waveguide is connected with one microwave resonance cavity, the impedance matcher is used for adjusting the frequency and standing wave of the microwaves and realizing impedance matching of microwave feeding, the inlet of the plasma generation chamber is connected with the outlets of the plurality of microwave resonance cavities, free electrons are formed at the boundary of the plasma generation chamber and the plurality of microwave resonance cavities, and the magnetic field module is used for generating a magnetic field, so that the free electrons make spiral motion in the plasma generation chamber and collide with background gas introduced into the plasma generation chamber to generate plasma. The electron cyclotron resonance ion source can realize multi-frequency microwave feeding and improve the uniformity of plasma.

Description

Technical Field

[0001] This invention relates to the field of transmission technology, and more specifically, to an electron cyclotron resonance ion source. Background Technology

[0002] An electron cyclotron resonance plasma source (ECR plasma source) is a device that generates plasma using the principle of electron cyclotron resonance. It is widely used in many fields due to its advantages such as high ionization and high stability, such as material surface modification in the field of materials science and semiconductor device manufacturing in the field of semiconductors.

[0003] However, current electron cyclotron resonant plasma sources can only feed microwaves of a single frequency, and the uniformity of the resulting plasma needs to be improved. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention innovatively provides an electron cyclotron resonance ion source. By setting up multiple microwave transmission modules and multiple microwave resonant cavities, multi-frequency microwave feeding can be achieved, which is beneficial to improving beam intensity and adjusting beam distribution, thereby enhancing the uniformity of the generated plasma.

[0005] To achieve the aforementioned technical objectives, this invention discloses an electron cyclotron resonance ion source, comprising multiple microwave transmission modules, multiple microwave resonant cavities, a plasma generation chamber, and a magnetic field module.

[0006] The microwave transmission module includes a microwave source, an impedance matching device, and a waveguide. The microwave source generates and emits microwaves. Multiple microwave transmission modules may generate microwaves at the same or different frequencies. The inlet of the waveguide is connected to the microwave source, and the outlet of the waveguide is connected to the microwave resonant cavity. The waveguide transmits microwaves to the microwave resonant cavity. The number of microwave resonant cavities is the same as the number of microwave transmission modules, and each waveguide corresponds to one microwave resonant cavity. The impedance matching device is disposed on the waveguide and is used to adjust the microwave frequency and standing wave ratio to achieve impedance matching of the microwave feed.

[0007] The inlet of the plasma generating chamber is connected to the outlet of a plurality of microwave resonant cavities, which feed microwaves into the plasma generating chamber, forming free electrons at the boundary between the plasma generating chamber and the plurality of microwave resonant cavities.

[0008] The magnetic field module is used to generate a magnetic field, which causes the free electrons to move in a spiral motion in the plasma generation chamber and collide with the background gas introduced into the plasma generation chamber to generate plasma.

[0009] Furthermore, an annular diaphragm is disposed inside the inlet end of the microwave resonant cavity, the diaphragm being used to increase the electric field strength within the microwave resonant cavity.

[0010] Furthermore, the thickness of the diaphragm is 0.5~2mm, and the inner radius of the diaphragm is 10mm±10%.

[0011] Furthermore, the microwave resonant cavity includes a high dielectric constant dielectric layer and a plasma arc insulator arranged sequentially along the inlet to outlet direction of the microwave resonant cavity.

[0012] Furthermore, the inlet end face of the waveguide is perpendicular to the outlet end face of the waveguide.

[0013] Furthermore, the impedance matching device includes a plurality of adjustment pins arranged circumferentially along the waveguide. The adjustment pins move relative to the waveguide, either inside or outside the waveguide, and the impedance is adjusted by adjusting the depth of the adjustment pins extending into the waveguide.

[0014] Furthermore, the magnetic field module includes a first group of permanent magnets and a second group of permanent magnets arranged sequentially along the direction from the inlet to the outlet of the plasma generation chamber, with a distance maintained between the first group of permanent magnets and the second group of permanent magnets.

[0015] Furthermore, the first set of permanent magnets includes two first permanent magnets arranged around the plasma generating chamber, the position of the first permanent magnets relative to the plasma generating chamber is adjustable, and the distance between the first permanent magnets and the plasma generating chamber is adjustable;

[0016] The second set of permanent magnets includes two second permanent magnets arranged around the plasma generating chamber. The position of the second permanent magnets relative to the plasma generating chamber is adjustable, and the distance between the second permanent magnets and the plasma generating chamber is adjustable.

[0017] Furthermore, a placement cavity is provided on the inner side of the plasma generating chamber, which is connected to the inner cavity of the plasma generating chamber. A solid metal compound is placed in the placement cavity for the formation and extraction of metal ions.

[0018] Furthermore, it also includes a cooling system that surrounds the microwave resonant cavity, and the cooling medium of the cooling system is in direct or indirect contact with the microwave resonant cavity.

[0019] The beneficial effects of this invention are as follows:

[0020] The electron cyclotron resonance ion source of the present invention, by setting up multiple microwave transmission modules and multiple microwave resonant cavities, can realize multi-frequency microwave feeding, which is beneficial to improve beam intensity and adjust beam distribution, thereby improving the uniformity of the generated plasma. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of the electron cyclotron resonance ion source according to an embodiment of the present invention.

[0022] Figure 2 This is a schematic diagram of the structure of a microwave resonant cavity according to an embodiment of the present invention.

[0023] Figure 3 This is a longitudinal sectional view of the microwave resonant cavity according to an embodiment of the present invention.

[0024] Figure 4 This is a comparison diagram of the electric field intensity inside the microwave resonant cavity corresponding to diaphragms with different inner radii.

[0025] Figure 5 This is a longitudinal sectional view of the plasma generation chamber and magnetic field module assembled according to an embodiment of the present invention.

[0026] Figure 6 This is a diagram showing the variation of the magnetic field along the axial direction.

[0027] Figure 7 This is a longitudinal sectional view of the plasma generation chamber according to an embodiment of the present invention.

[0028] Figure 8 This is a schematic diagram of the assembly of a microwave resonant cavity and a cooling system according to an embodiment of the present invention.

[0029] Figure 9 This is a schematic diagram of the cooling system according to another embodiment of the present invention.

[0030] In the picture,

[0031] 1. Microwave transmission module; 11. Microwave source; 12. Impedance matching device; 121. Adjustment pin; 13. Waveguide; 2. Microwave resonant cavity; 21. Diaphragm; 22. High dielectric constant dielectric layer; 23. Plasma arc insulator; 3. Plasma generation chamber; 31. Inner cavity; 32. Placement cavity; 33. Air inlet; 4. Magnetic field module; 41. First group of permanent magnets; 411. First permanent magnet; 42. Second group of permanent magnets; 421. Second permanent magnet; 43. Outer shell; 44. Cover plate; 45. Screw; 5. Cooling system; 51. Housing; 52. Cover; 6. Extension waveguide. Detailed Implementation

[0032] The electron cyclotron resonance ion source provided by the present invention will be explained and described in detail below with reference to the accompanying drawings.

[0033] This embodiment specifically discloses an electron cyclotron resonance ion source, such as... Figure 1 As shown, the system includes multiple microwave transmission modules 1, multiple microwave resonant cavities 2, a plasma generation chamber 3, and a magnetic field module 4. Each microwave transmission module 1 includes a microwave source 11, an impedance matching device 12, and a waveguide 13. The microwave source 11 generates and emits microwaves. The microwaves generated by the microwave sources 11 in the multiple microwave transmission modules 1 may have the same or different frequencies. The inlet of the waveguide 13 is connected to the microwave source 11, and the outlet of the waveguide 13 is connected to the microwave resonant cavity 2. The waveguide 13 is used to transmit microwaves to the microwave resonant cavity 2. The number of microwave resonant cavities 2 is the same as the number of microwave transmission modules 1, and each waveguide 13 is connected to one microwave resonant cavity 2. The impedance matching device 12 is installed on the waveguide 13 and is used to adjust the frequency and standing wave of the microwaves, achieving impedance matching for microwave feeding. The arrangement of multiple microwave transmission modules 1 and multiple microwave resonant cavities 2 enables multi-frequency microwave feeding, frequency adjustment, and impedance matching, which is beneficial for improving beam intensity and adjusting beam distribution, thereby enhancing the uniformity of the generated plasma.

[0034] The inlet of the plasma generating chamber 3 is connected to the outlet of multiple microwave resonant cavities 2. The multiple microwave resonant cavities 2 are used to feed microwaves into the plasma generating chamber 3, and free electrons are formed at the boundary between the plasma generating chamber 3 and the multiple microwave resonant cavities 2.

[0035] The magnetic field module 4 is used to generate a magnetic field, which causes free electrons to move in a spiral motion in the plasma generation chamber 3 and collide with the background gas introduced into the plasma generation chamber 3 to generate plasma.

[0036] The number of microwave transmission module 1 and microwave resonant cavity 2 is at least two, and the specific number is set according to actual needs. Microwave source 11 can be a magnetron or a solid-state generator.

[0037] In some optional embodiments, the electron cyclotron resonance ion source also includes an isolator disposed between the microwave source 11 and the waveguide 13. The isolator serves as an isolation protection module, utilizing its non-reciprocal characteristics to achieve unidirectional transmission of microwave energy, blocking reverse power backflow, ensuring forward power transmission efficiency >95%, and achieving long-term stable operation of the electron cyclotron resonance ion source.

[0038] The electron cyclotron resonance ion source of this application can employ multi-frequency microwave mixing technology (such as superimposing S-band and C-band microwaves) to expand the plasma ionization region, significantly improve ionization efficiency, and adjust the uniformity of the generated plasma.

[0039] In some optional embodiments, the inlet end face of waveguide 13 is perpendicular to the outlet end face of waveguide 13. Waveguide 13 can be L-shaped or arc-shaped. Waveguide 13 forms the main path for microwave transmission. Multiple independent waveguides 13 support multi-band operating modes. The microwaves entering multiple waveguides 13 can be of the same frequency or different frequencies. The perpendicularity of the inlet end face and outlet end face of waveguide 13 can constrain the microwave transmission path. Furthermore, when the outlet end faces of multiple waveguides 13 are clustered, the inlets of multiple waveguides 13 are kept as far apart as possible, providing sufficient space for the microwave source 11 and the isolator, facilitating the arrangement of multiple microwave sources 11.

[0040] Optionally, the cross-section of waveguide 13 is rectangular to avoid microwave cutoff. In this embodiment, the transverse direction is perpendicular to the axial direction, and the longitudinal direction can also be referred to as the axial direction.

[0041] In some optional embodiments, the impedance matching device 12 includes a plurality of adjustment pins 121 arranged circumferentially along the waveguide 13. The adjustment pins 121 move relative to the waveguide 13, either inside or outside the waveguide 13, and the impedance is adjusted by varying the depth of the adjustment pins 121 within the waveguide 13. The number of adjustment pins 121 on each waveguide 13 is set as needed, and the number and arrangement of the adjustment pins 121 on multiple waveguides 13 can be the same or different, meaning the multiple impedance matching devices 12 are independent of each other. Preferably, the multiple adjustment pins 121 are positioned at the center of the waveguide 13 in the axial direction, and are circumferentially distributed around the surface of the waveguide 13. The adjustment pins 121 are used to adjust the frequency and standing wave, achieving impedance matching for microwave feeding, improving the actual feed power, reducing the reflected power, and improving the operating efficiency of the electron cyclotron resonance ion source.

[0042] The adjusting pin 121 can be a pin shaft. A through hole can be opened on the waveguide 13 for the pin shaft to pass through and slide. The pin shaft is interference-fitted with the waveguide 13. The impedance is adjusted by adjusting the depth of the pin shaft inserted into the waveguide 13.

[0043] The adjusting pin 121 can be a screw. A threaded hole matching the screw is opened on the waveguide 13. The screw is screwed into the threaded hole on the waveguide 13, and the impedance is adjusted by adjusting the depth of the screw screw into the waveguide 13.

[0044] The adjusting pin 121 can be made of metal or non-metal; non-metallic materials can include ceramics.

[0045] In some alternative embodiments, such as Figure 2 and 3As shown, the microwave resonant cavity 2 includes a high dielectric constant dielectric layer 22 and a plasma arc insulator 23 arranged sequentially from the inlet to the outlet of the microwave resonant cavity 2. The high dielectric constant dielectric layer 22 makes it difficult for microwaves to be cut off. The high dielectric constant dielectric layer 22 can be made of ceramic or diamond. By changing the material used for the high dielectric constant dielectric layer 22, the diameter and length of the microwave resonant cavity 2 can be changed. The plasma arc insulator 23 can be made of boron nitride. The plasma arc insulator 23 has two functions: first, to generate electrons through ionization in a high electric field; and second, to prevent plasma from damaging the high dielectric constant dielectric layer 22. The specific length ratio of the high dielectric constant dielectric layer 22 and the plasma arc insulator 23 is set according to actual needs, and this application does not make any special limitations. Generally, the length of the high dielectric constant dielectric layer 22 is greater than the length of the plasma arc insulator 23.

[0046] The inner cavity of microwave resonant cavity 2 is cylindrical, but it can also be other shapes, but it must meet the resonant characteristics.

[0047] In some alternative embodiments, such as Figure 2 and 3 As shown, an annular diaphragm 21 is disposed inside the inlet end (i.e., microwave feed end) of the microwave resonant cavity 2. The diaphragm 21 is used to increase the electric field intensity inside the microwave resonant cavity 2. Specifically, the diaphragm 21 is disposed inside a high dielectric constant dielectric layer 22.

[0048] The electric field strength of the microwave resonant cavity 2, especially the electric field strength on the side near the plasma generation chamber 3, determines the ionization capability of microwaves of a certain power to the gas, thereby determining the ability of the electron cyclotron resonance ion source to generate an ion beam. In this application, a diaphragm 21 is designed in the microwave resonant cavity 2 to improve the electric field strength in the microwave resonant cavity 2.

[0049] The diaphragm 21 can be made of a low-loss metal (such as copper). The inner cavity of the microwave resonant cavity 2 is cylindrical, and the diaphragm 21 is shaped like a concentric ring. The outer side of the diaphragm 21 can be connected to the microwave resonant cavity 2 or integrally formed, and the inner side of the diaphragm 21 is a cavity.

[0050] The arrangement of the diaphragm 21 inside the microwave resonant cavity 2 in this application enables unidirectional microwave transmission, preventing microwaves from dissipating back in the opposite direction. Furthermore, it significantly improves the Q-factor (quality factor) and voltage of the microwave resonant cavity 2, resulting in a noticeable effect on increasing ion beam current and reducing standing waves. The Q-factor of the microwave resonant cavity 2 is a crucial indicator of its performance, describing its energy loss and storage capacity; a higher Q-factor corresponds to a higher voltage.

[0051] In some optional embodiments, the thickness of the diaphragm 21 is 0.5~2mm, and the inner radius of the diaphragm 21 is 10mm±10%.

[0052] like Figure 3 As shown, after microwaves enter the microwave resonant cavity 2, they pass sequentially through the diaphragm 21, the high dielectric constant dielectric layer 22, and the plasma arc insulator 23. Plasma is generated on the surface of the plasma arc insulator 23. The microwaves resonate in the microwave resonant cavity 2, especially in the high dielectric constant dielectric layer 22, to form a high electric field, which is conducive to the ionization of plasma. The function of the diaphragm 21 is to prevent the microwave energy in the microwave resonant cavity 2 from diffusing back into the waveguide 13. Although this will enhance the electric field in the waveguide 13, energy is conserved. This will reduce the overall electric field strength of the microwave resonant cavity 2, and the electric field strength on the side closer to the plasma generation chamber 3 will also decrease, which is not conducive to the formation of plasma. Therefore, the inner radius of the diaphragm 21 needs to meet the microwave cutoff requirement. For example, a cavity (air) with an inner radius of 10 mm is cut off from 2.45 GHz microwaves. It should be noted that the thickness (axial dimension) of the diaphragm 21 cannot be too large, because the diaphragm 21 is cut off from microwaves. If the thickness is too large, the microwave power reaching the high dielectric constant dielectric layer 22 will be insufficient, which will also reduce the electric field strength of the microwave resonant cavity 2. The thickness of the diaphragm 21 in this application is 0.5~2 mm, which effectively solves the above problems.

[0053] Figure 4 The results of the electric field simulation using Comsol software under a 1000W power feed are shown. The simulation conditions are as follows: the inner cavities of the multiple microwave resonant cavities 2 of the electron cyclotron resonance ion source are all cylindrical, and the electric field intensity distribution within each microwave resonant cavity 2 is centrally symmetrical. Any one microwave resonant cavity 2 is selected as the simulation object. Specifically, any diameter of the exit end face (i.e., the end face near the plasma generation chamber 3) of the plasma arc insulator 23 of this microwave resonant cavity 2 is selected as the horizontal axis (i.e., the X-axis), and the vertical axis represents the electric field intensity at different positions along this diameter. The coordinate 0 point represents the position where this diameter intersects the central axis of the plasma arc insulator 23. Figure 4 Figure a shows the electric field strength when the inner radius of diaphragm 21 is 16.5 mm (close to the value without diaphragm 21). Figure 4 Figure b shows the electric field strength when the inner radius of the membrane 21 is 10 mm. It can be seen that when the inner radius of the membrane 21 is 10 mm, both the overall electric field strength and the peak value are significantly improved, approaching twice the electric field strength when the inner radius of the membrane 21 is 16.5 mm (close to the electric field strength without the membrane 21). The plasma and ion beam are also significantly enhanced.

[0054] In some alternative embodiments, such as Figure 1As shown, the magnetic field module 4 includes a first set of permanent magnets 41 and a second set of permanent magnets 42 arranged sequentially along the direction from the inlet to the outlet of the plasma generation chamber 3. A distance is maintained between the first set of permanent magnets 41 and the second set of permanent magnets 42. The magnetic field module 4 is used to generate an axial magnetic field. Microwaves generate a very high electric field in the microwave resonant cavity 2. This high electric field at the boundary between the microwave resonant cavity 2 and the plasma generation chamber 3 ionizes and binds electrons, forming free electrons. The magnetic field generated by the magnetic field module 4 causes these free electrons to undergo a Lorentz force, forming a helical trajectory. This magnetic field confinement increases the mean free path of electrons to several times that of the unmagnetized area, significantly increasing the collision cross-section with background gas molecules. In addition to increasing the mean free path of electrons, the magnetic field also enables electrons to achieve electron cyclotron resonance heating (ECRH) at the interface between the microwave resonant cavity 2 and the plasma generation chamber 3. Electrons continuously absorb energy and become free electrons, greatly increasing the probability of plasma formation.

[0055] In some alternative embodiments, such as Figure 5 As shown, the first group of permanent magnets 41 includes two first permanent magnets 411 arranged around the plasma generating chamber 3. The positions of the first permanent magnets 411 relative to the plasma generating chamber 3 are adjustable, and the distance between the first permanent magnets 411 and the plasma generating chamber 3 is adjustable. The second group of permanent magnets 42 includes two second permanent magnets 421 arranged around the plasma generating chamber 3. The positions of the second permanent magnets 421 relative to the plasma generating chamber 3 are adjustable, and the distance between the second permanent magnets 421 and the plasma generating chamber 3 is adjustable. Preferably, the two first permanent magnets 411 and the two second permanent magnets 421 are arranged opposite each other. Figure 6 The diagram shows the variation of the axial magnetic field intensity generated by the magnetic field module along the axis of plasma generation chamber 3. Figure 6 As can be seen, the magnetic field module 4 generates a "hump-shaped" axial magnetic field within the plasma generation chamber 3. This magnetic field reaches a resonant magnetic field with a specific frequency of microwaves at the interface between the microwave resonant cavity 2 and the plasma generation chamber 3. Electrons continuously absorb energy under the resonant magnetic field. The plasma in the concave region in the middle of the "hump" of the axial magnetic field in the plasma generation chamber 3 is affected by the magnetic mirror effect. Electrons continuously circulate within the magnetic mirror, greatly increasing the probability of collision with the background gas, thereby increasing the plasma density. A magnetic field as low as possible is designed at the exit of the plasma generation chamber 3 so that the ions exiting the plasma generation chamber 3 have no angle or deviation from that direction, reducing the impact on the trajectory of the extracted ion beam.

[0056] The positions of the first permanent magnet 411 and the second permanent magnet 421 relative to the plasma generating chamber 3 are adjustable. The distance between the first permanent magnet 411 and the plasma generating chamber 3 is adjustable, and the distance between the second permanent magnet 421 and the plasma generating chamber 3 is adjustable, so that the generated axial magnetic field can be adjusted, thereby changing the magnitude and distribution of the axial magnetic field.

[0057] The arrangement and shape of the first permanent magnet 411 and the second permanent magnet 421 only need to satisfy the requirement of combining them to achieve... Figure 6 The bimodal characteristics along the axis of plasma generation chamber 3 are shown, and the magnetic field at the outlet of plasma generation chamber 3 is very small.

[0058] Optionally, the first permanent magnet 411 and the second permanent magnet 421 are rectangular.

[0059] like Figure 5 As shown, both the first permanent magnet 411 and the second permanent magnet 421 are provided with a shell 43, which is used to connect the first permanent magnet 411 and the second permanent magnet 421 to the plasma generating chamber 3. The shell 43 may be L-shaped, and a cavity perpendicular to the axis of the plasma generating chamber 3 is provided inside the shell 43. The first permanent magnet 411 and the second permanent magnet 421 are placed in the corresponding cavity of the shell 43. The portion of the shell 43 parallel to the axis of the plasma generating chamber 3 is connected to the plasma generating chamber 3 by screws 45. An opening may be opened at the end of the shell 43 away from the plasma generating chamber 3, and the opening communicates with the cavity inside the shell 43. A cover plate 44 is installed at the opening of the shell 43, and the cover plate 44 can be connected to the shell 43 by screws 45, so as to fix the first permanent magnet 411 and the second permanent magnet 421 respectively inside the corresponding shell 43.

[0060] Multiple threaded holes can be provided on the plasma generating chamber 3. The position of the outer shell 43 can be adjusted by selecting the position of the screw 45 screwed into the threaded hole, thereby adjusting the position of the first permanent magnet 411 and the second permanent magnet 421.

[0061] Optionally, a shim can be provided between the outer shell 43 and the plasma generating chamber 3. By adjusting the number of shims between the outer shell 43 and the plasma generating chamber 3, the distance between the first permanent magnet 411 and the plasma generating chamber 3 and the distance between the second permanent magnet 421 and the plasma generating chamber 3 can be adjusted, thereby achieving the adjustability of the magnetic field.

[0062] like Figure 5 As shown, an air inlet 33 is provided on the side wall of the plasma generation chamber 3 for introducing background gas into the plasma generation chamber 3.

[0063] In some alternative embodiments, such as Figure 7As shown, a placement cavity 32 is provided on the side of the inner cavity 31 of the plasma generating chamber 3. The placement cavity 32 is connected to the inner cavity 31 of the plasma generating chamber 3. The inner cavity 31 is the plasma generation area, and the placement cavity 32 contains a solid metal compound for the formation and extraction of metal ions. The solid metal compound vaporizes and enters the plasma area under the high temperature generated by the auxiliary gas plasma formation and microwave resonance. Metal ions are automatically formed and extracted through electron collision ionization. For some metal ions, no additional crucible or furnace is required to provide metal gas, nor is a corresponding heating power source required.

[0064] Under the influence of a high electric field and high energy density, the high dielectric constant dielectric layer 22 of the microwave resonant cavity 2 generates significant Joule heating, leading to a sharp increase in material temperature. Based on this, in some optional embodiments, such as... Figure 8 and 9 As shown, the electron cyclotron resonance ion source of this application also includes a cooling system 5, which surrounds the microwave resonant cavity 2. The cooling medium of the cooling system 5 is in direct or indirect contact with the microwave resonant cavity 2, thereby reducing the temperature of the microwave resonant cavity 2 and extending the service life of the electron cyclotron resonance ion source.

[0065] The cooling medium can be ice or cooling water. For ease of sourcing and the fluidity of the cooling medium, cooling water is preferred.

[0066] In one embodiment, such as Figure 8 As shown, the cooling medium of the cooling system 5 is in direct contact with the microwave resonant cavity 2. The cooling system 5 includes a housing 51, a cover 52, and a cooling medium. A first opening matching the shape of the microwave resonant cavity 2 can be opened in the middle of the housing 51. A second opening matching the shape of the microwave resonant cavity 2 is provided on the end face of the housing 51 away from the waveguide 13. The cover 52 is installed at the second opening. A sealing ring can be provided between the housing 51 and the cover 52 to achieve a seal. The microwave resonant cavity 2 is fixed inside the housing 51, and the inlet end of the microwave resonant cavity 2 is connected to the first opening, and the outlet end is connected to the second opening. The housing 51, the cover 52, and the microwave resonant cavity 2 form a cavity for placing the cooling medium. The cooling medium is placed in this cavity, surrounds the microwave resonant cavity 2, and is in direct contact with the microwave resonant cavity 2. A cooling medium outlet and a cooling medium inlet can be provided on the housing 51 or the cover 52. If the cooling medium is cooling water, the cooling water can enter the cavity from the cooling medium inlet and flow out of the cavity from the cooling medium outlet, which can realize the circulation of cooling water and enhance the cooling effect. Both the cooling medium outlet and the cooling medium inlet can be threaded holes, which facilitates connection to the cooling medium flow pipeline.

[0067] To facilitate connection with waveguide 13, an extension waveguide 6 is provided on the end face of housing 51 near waveguide 13. The extension waveguide 6 is connected to waveguide 13 to improve the flexibility of the microwave resonant cavity 2 position. The extension waveguide 6 can also affect the impedance matching to a certain extent. The extension waveguide 6 can be connected to housing 51 by screws.

[0068] In another embodiment, such as Figure 9 As shown, the cooling system 5 includes a housing 51 and a cooling medium inside the housing 51. The housing 51 is a closed structure with an internal cavity. A through hole matching the shape of the microwave resonant cavity 2 is opened at the center of the housing 51. The housing 51 is directly fitted onto the microwave resonant cavity 2. A cooling medium inlet pipe and a cooling medium outlet pipe are connected to the housing 51 to realize the circulation of the cooling medium. In this embodiment, the cooling medium is separated from the microwave resonant cavity 2, and the cooling medium is in indirect contact with the microwave resonant cavity 2, which improves the design freedom of the microwave resonant cavity 2.

[0069] The working process of the electron cyclotron resonance ion source in this application is as follows:

[0070] After receiving control commands from the control terminal, microwave source 11 outputs electromagnetic waves in multiple frequency bands. The power and frequency of microwave source 11 are adjustable. After the microwave signal is adjusted by impedance matching device 12 or the frequency of microwave source 11 is finely adjusted, the standing wave ratio (VSWR) drops below 1.1, realizing efficient transmission of microwave energy to microwave resonant cavity 2. Microwave resonant cavity 2 excites electromagnetic field resonance through a specific mode, significantly enhancing the electric field strength and thus improving energy focusing efficiency. In the boundary region between microwave resonant cavity 2 and plasma generation chamber 3, the axial magnetic field generated by magnetic field module 4 forms an electron cyclotron resonance (ECR) effect with the microwave electric field. The cyclotron frequency of the electrons is precisely matched with the feed microwave frequency, realizing resonant energy transfer. In the resonance region, electrons continuously absorb microwave energy, increasing their kinetic energy to 10–100 eV. After reaching the ionization threshold, they break free from the atomic nucleus and form a high-energy free electron swarm. The free electrons undergo avalanche-like collision ionization with the background gas (such as hydrogen or argon) introduced into plasma generation chamber 3, forming a high-density plasma.

[0071] The microwave transmission module 1 of this application is configured with multiple modules, which cooperate with multiple microwave resonant cavities 2 to achieve multi-frequency microwave feeding. This is beneficial for improving beam intensity and adjusting beam distribution, and can adjust the uniformity of the generated plasma. It also makes the microwave ion source applicable to a wider range of ions. A circular diaphragm 21 is designed inside the microwave resonant cavity 2, with an air cavity inside the diaphragm 21 to meet the cutoff of the ion source's operating frequency. The diaphragm 21 can significantly improve the electric field intensity of the microwave resonant cavity 2, thereby increasing the intensity of the plasma and ion beam. A solid metal compound placement cavity 32 is reserved in the plasma generation chamber 3, which can realize the automatic formation and extraction of metal ions.

[0072] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0073] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0074] In the description of this specification, the references to terms such as "this embodiment," "an embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in a suitable manner in any at least one embodiment or example. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0075] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0076] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and simple improvements made on the substantive content of the present invention should be included within the protection scope of the present invention.

Claims

1. An electron cyclotron resonance ion source, characterized by, The microwave transmission module comprises a microwave source, an impedance matcher and a waveguide, the microwave source is used to generate and emit microwaves, the microwave sources of a plurality of microwave transmission modules generate microwaves with the same or different frequencies, the inlet of the waveguide is connected with the microwave source, the outlet of the waveguide is connected with the microwave resonance cavity, the waveguide is used to transmit microwaves to the microwave resonance cavity, the number of the microwave resonance cavities is the same as that of the microwave transmission modules, each waveguide is connected with one microwave resonance cavity, the impedance matcher is arranged on the waveguide, and the impedance matcher is used to adjust the frequency and standing wave of microwaves and realize impedance matching of microwave feeding. The inlet of the plasma generation chamber is connected with the outlets of a plurality of microwave resonance cavities, and the microwave resonance cavities are used to feed microwaves into the plasma generation chamber, and free electrons are formed at the boundary between the plasma generation chamber and the microwave resonance cavities. The magnetic field module is used to generate a magnetic field, so that the free electrons perform spiral motion in the plasma generation chamber and collide with the background gas introduced into the plasma generation chamber to generate plasma. The inlet end of the microwave resonance cavity is internally provided with an annular diaphragm, and the diaphragm is used to improve the electric field intensity in the microwave resonance cavity.

2. The electron cyclotron resonance ion source of claim 1, wherein, The thickness of the diaphragm is 0.5-2 mm, and the inner radius of the diaphragm is 10 mm±10%.

3. The electron cyclotron resonance ion source of claim 2, wherein The microwave resonance cavity comprises a high dielectric constant dielectric layer and a plasma arc insulator arranged in sequence along the inlet-to-outlet direction of the microwave resonance cavity.

4. The electron cyclotron resonance ion source according to any of claims 1 to 3, characterized in that The inlet end surface of the waveguide is perpendicular to the outlet end surface of the waveguide.

5. The electron cyclotron resonance ion source of claim 1, wherein, The impedance matcher comprises a plurality of adjusting pins arranged in the circumferential direction of the waveguide, the adjusting pins move towards the inside or outside of the waveguide relative to the waveguide, and the impedance is adjusted by adjusting the depth of the adjusting pins extending into the waveguide.

6. The electron cyclotron resonance ion source of claim 1, wherein, The magnetic field module comprises a first group of permanent magnets and a second group of permanent magnets arranged in sequence along the inlet-to-outlet direction of the plasma generation chamber, and a distance is maintained between the first group of permanent magnets and the second group of permanent magnets.

7. The electron cyclotron resonance ion source of claim 1, wherein, The first group of permanent magnets comprises two first permanent magnets arranged around the plasma generation chamber, the positions of the first permanent magnets relative to the plasma generation chamber are adjustable, and the distance between the first permanent magnets and the plasma generation chamber is adjustable.

8. The electron cyclotron resonance ion source of claim 7, wherein, The second group of permanent magnets comprises two second permanent magnets arranged around the plasma generation chamber, the positions of the second permanent magnets relative to the plasma generation chamber are adjustable, and the distance between the second permanent magnets and the plasma generation chamber is adjustable. The inner cavity side of the plasma generation chamber is provided with a placement cavity in communication with the inner cavity of the plasma generation chamber, and a solid metal compound is placed in the placement cavity to form and lead out metal ions.

9. The electron cyclotron resonance ion source of claim 1, wherein, A cooling system is further included, the cooling system surrounds the microwave resonance cavity, and the cooling medium of the cooling system is in direct or indirect contact with the microwave resonance cavity.

10. The electron cyclotron resonance ion source of claim 1, wherein, ​

Images