Radio frequency ion source apparatus, feed network, and radio frequency ion source system

Abstract

This application relates to a radio frequency (RF) ion source device, a feed network, and a RF ion source system. The RF ion source device includes a windowed induction support frame and a multi-turn rectangular helical coil. The interior space of the windowed induction support frame serves as a rectangular discharge chamber. Multiple induction perforated windows are provided on the sidewalls of the support frame, and adjacent induction perforated windows are separated by longitudinal reinforcing ribs. The multi-turn rectangular helical coil is three-dimensionally wrapped around the outside of the support frame, and each turn of the coil spans the induction perforated windows to radiate an inducing electromagnetic field into the interior space through the windows. The RF ion source device, feed network, and RF ion source system provided by this application can suppress energy loss and improve the uniformity of the large-area rectangular particle number flux.

Description

Technical Field

[0001] This application relates to the field of radio frequency plasma generation technology, and in particular to radio frequency ion source devices, feed networks, and radio frequency ion source systems. Background Technology

[0002] In semiconductor precision etching and ion beam assisted deposition processes, achieving large-area, highly uniform plasma generation is a core technological requirement.

[0003] Currently, mainstream radio frequency ion sources in the industry typically employ planar helical coils. These coils are positioned above the dielectric window at the top of the discharge chamber. However, with the continuous increase in the size of the processing substrate, planar helical coils face insurmountable technical bottlenecks: their induced electromagnetic field is mainly concentrated in a two-dimensional shallow region below the dielectric window, and the energy distribution exhibits a high-center, low-edge characteristic, making them highly susceptible to central distortion of plasma density when expanded over large areas. Furthermore, the strong electrostatic coupling caused by the planar structure leads to severe ion bombardment of the dielectric window, resulting in sputter contamination.

[0004] To overcome the limitations of planar structures, the industry has experimented with using cylindrical spiral coils to surround the discharge chamber in a three-dimensional manner. While this three-dimensional approach improves field penetration depth, it still presents significant limitations when dealing with large rectangular discharge spaces.

[0005] Geometric matching and edge coverage blind zone: The circular sensing structure cannot achieve effective spatial matching with the rectangular cavity, resulting in a significant decrease in plasma density at the end of the long axis and corner areas of the cavity.

[0006] Rectangularization leads to field strength distortion and phase distortion: If the coil is simply changed to a rectangular structure to fit the cavity, the sharp turn of the radio frequency current at the corner of the rectangle will cause severe charge accumulation and electromagnetic field distortion. At the same time, the long path of a large rectangular coil will cause significant radio frequency phase delay, resulting in spatial inconsistency in energy coupling along the long axis.

[0007] The trade-off between structural integration and eddy current losses: Large-area rectangular coils must rely on a robust, windowed induction support frame. However, traditional continuous metal frames generate huge induced eddy currents under RF fields, leading to significant energy loss and frame heating.

[0008] Electrical imbalance in long-path power supply: The long-distance, asymmetrical lead layout of rectangular coils can introduce complex parasitic inductance, resulting in extreme impedance imbalance at both ends of the coil, which can lead to matching instability or high-voltage arcing.

[0009] Therefore, designing a radio frequency ion source device that can overcome the two-dimensional coupling limitations of planar coils, eliminate the angular distortion and phase delay caused by rectangular three-dimensional coils, and achieve impedance self-balancing while reducing frame eddy current losses is a key technical bottleneck that urgently needs to be solved in this field. Summary of the Invention

[0010] Therefore, it is necessary to provide a radio frequency ion source device, a power supply network, and a radio frequency ion source system to address the above problems.

[0011] A radio frequency ion source device, comprising:

[0012] The windowed induction support frame has an internal space that serves as a rectangular discharge chamber. The side walls of the windowed induction support frame are provided with multiple induction cutout windows, and adjacent induction cutout windows are separated by longitudinal reinforcing ribs to reduce the circumferential induction eddy currents of the windowed induction support frame while maintaining structural strength.

[0013] A multi-turn rectangular spiral coil is three-dimensionally wrapped around the outside of the windowed induction support frame, and each turn of the multi-turn rectangular spiral coil is set across the induction cutout window to radiate the induction electromagnetic field into the internal space through the induction cutout window.

[0014] The multi-turn rectangular spiral coil includes a starting feed section and an ending feed section. Both the starting feed section and the ending feed section are led out from a non-centrally symmetrical position on one side of the long side of the multi-turn rectangular spiral coil to the bottom of the windowed induction support frame. One of the sections is set vertically downward from the top layer winding and across the remaining turns of the multi-turn rectangular spiral coil to compensate for the radio frequency phase delay of the multi-turn rectangular spiral coil in the long axis direction through an asymmetrical physical path.

[0015] In one embodiment, the multi-turn rectangular spiral coil is wound with a hollow water-cooled copper tube, and the lead-out positions of the starting and ending feed sections are located within 1 / 5 to 1 / 3 of the length of one long side.

[0016] In one embodiment, the multi-turn rectangular spiral coil has a smooth arc transition at the corner, and the ratio of the total area of ​​the sensing cutout window to the total area of ​​the side wall of the windowed sensing support frame is greater than 60%.

[0017] In one embodiment, the top of the windowed sensing support frame is provided with an ion extraction grid, the bottom of the windowed sensing support frame is provided with a gas distribution structure, and the starting power supply section and the ending power supply section extend in the same direction to the vicinity of the gas distribution structure for electrical connection.

[0018] A feed network for a radio frequency ion source device includes:

[0019] The first symmetrical compensation branch and the second symmetrical compensation branch are respectively connected in series at the start and end of the radio frequency ion source coil;

[0020] The resonant adjustment branch is connected between the first and second symmetrical compensation branches;

[0021] The first and second symmetrical compensation branches each include at least one lumped parameter compensation inductor to construct an RF potential balance point on the RF ion source coil and to compensate for the parasitic inductance caused by the asymmetrical arrangement of the RF ion source coil leads.

[0022] In one embodiment, the first compensation inductor in the first symmetrical compensation branch and the second compensation inductor in the second symmetrical compensation branch have equal inductive reactance values ​​and are symmetrically arranged at the output end of the power supply network.

[0023] In one embodiment, the resonant adjustment branch includes a third compensation inductor, which together with the first and second symmetrical compensation branches constitutes a multi-pole resonant network.

[0024] In one embodiment, the power supply network further includes a phase detection circuit for sampling the potential difference between the first and second symmetrical compensation branches in real time, and adjusting the variable capacitor in the multi-pole resonant network according to the feedback signal generated by the potential difference.

[0025] A radio frequency ion source system, comprising:

[0026] As before, the radio frequency ion source device;

[0027] As before, the feed network is electrically connected between the radio frequency power supply and the radio frequency ion source device;

[0028] The power supply network compensates for the inductance by using lumped parameters to offset the impedance imbalance caused by the non-centrally symmetrical position of the multi-turn rectangular spiral coil.

[0029] In one embodiment, the power supply network is integrated at the bottom of the radio frequency ion source device and shares an electrical shield with the gas distribution structure at the bottom of the windowed induction support frame.

[0030] This invention achieves the following significant technical effects through the synergy of specific physical structure reconstruction and electromagnetic field coupling mechanisms:

[0031] 1. Deep suppression of energy loss by the window-pane induction support frame

[0032] By setting multiple induction-perforated windows on the sidewalls of the windowed induction support frame and using longitudinal reinforcing ribs for spatial separation, this device physically breaks the closed path of circumferential current in the metal frame under the radio frequency field. This feature can significantly reduce the induced eddy currents generated inside the windowed induction support frame, reduce the Joule heat loss of the metal frame due to the eddy current effect, and thus direct more radio frequency energy to the internal discharge space through the induction-perforated windows, greatly improving the power conversion efficiency in the plasma generation process.

[0033] 2. Physical reconstruction of large-area uniformity using a rectangular stereoscopic sensing architecture

[0034] This device employs a multi-turn rectangular helical coil that surrounds the outside of a window-like induction support frame, with its rectangular geometry precisely matching the spatial shape of the internal discharge chamber. Compared to traditional planar or circular helical coils, this three-dimensional, fully enclosed coupling method ensures deep penetration and uniform coverage of the induced electromagnetic field along its long axis, eliminating edge coverage blind spots during large-area discharge processes and providing a physical basis for obtaining highly uniform rectangular large-area ion beams.

[0035] 3. Dynamic compensation for phase delay derived from non-centrosymmetric co-directional extraction.

[0036] By placing both the initial and final feed sections of the coil at non-centrosymmetric positions along its long side, an asymmetric current path is artificially created. Since radio frequency waves inherently experience phase delay when propagating through a large rectangular coil, the mutual inductance effect generated by this asymmetric layout can counteract the phase fluctuations along the long axis of the coil. This design, which compensates for electromagnetic distortion with an asymmetric structure, ensures spatial consistency of plasma density along the long axis, solving the problem of uneven field distribution commonly found in large-size ion sources.

[0037] 4. Directional regulation of parasitic parameters by vertically downward spanning layout

[0038] The initial feed section, positioned vertically downwards from the top winding across the remaining turns, not only achieves centralized integration of the feed point towards the bottom, but more importantly, this specific crossing path creates controlled distributed parameter coupling between the feed and each turn. This structural feature provides a clear physical reference for lumped parameter compensation in the subsequent feed network, making it possible to precisely balance the potential across the coil terminals via external circuitry. This effectively suppresses high-voltage overshoot, avoids arcing failures at coil corners or insulation supports, and significantly improves the reliability of the equipment under high-power, long-term operation. Attached Figure Description

[0039] Figure 1This is a three-dimensional structural schematic diagram of a radio frequency ion source device provided in an embodiment of this application.

[0040] Figure 2 for Figure 1 A schematic diagram of the three-dimensional structure of the radio frequency ion source device shown from another perspective.

[0041] Figure 3 for Figure 1 A three-dimensional structural schematic diagram of the windowed induction support frame of the radio frequency ion source device shown.

[0042] Figure 4 For this application Figure 1 The diagram shows a three-dimensional structure of a multi-turn rectangular spiral coil in a radio frequency ion source device.

[0043] Figure 5 This is a schematic diagram of the topology of a power supply network provided in an embodiment of this application. Detailed Implementation

[0044] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0045] In the description of this application, it should be understood that if terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0046] Furthermore, where the terms "first" and "second" appear, these terms are 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 with "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, where the term "multiple" appears, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0047] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," 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 expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0048] In this application, unless otherwise expressly specified and limited, the use of descriptions such as "above" or "below" the second feature indicates that the first and second features are in direct contact or indirect contact via an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. Similarly, "below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0049] It should be noted that if an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. If an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. If so, the terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application are for illustrative purposes only and do not represent the only possible implementation.

[0050] Please refer to Figures 1-4 , Figure 1 This is a three-dimensional structural schematic diagram of a radio frequency ion source device provided in an embodiment of this application. Figure 2 for Figure 1 A schematic diagram of the three-dimensional structure of the radio frequency ion source device shown from another perspective. Figure 3 for Figure 1 A three-dimensional structural schematic diagram of the windowed induction support frame of the radio frequency ion source device shown. Figure 4 For this application Figure 1 The diagram shows a three-dimensional structural schematic of a multi-turn rectangular spiral coil in a radio frequency ion source device. One embodiment of this application provides a radio frequency ion source device including a windowed induction support frame 10 and a multi-turn rectangular spiral coil 20.

[0051] The windowed induction support frame 10 is a metal frame, and its internal space serves as a rectangular discharge chamber. Multiple induction cutout windows 11 are provided on the side walls of the windowed induction support frame 10, and adjacent induction cutout windows 11 are separated by longitudinal reinforcing ribs 12 to reduce circumferential induced eddy currents while maintaining structural strength. In some embodiments, an insulating dielectric plate 50 is provided corresponding to the induction cutout windows 11. The high transmittance characteristics of the insulating dielectric plate 50, combined with the structural support characteristics of the metal frame, construct a directional induction coupling channel. While maintaining the high vacuum integrity of the rectangular discharge chamber, the insulating dielectric plate 50 effectively suppresses the capacitive coupling component of the RF coil to the interior of the chamber and reduces sputtering contamination caused by ion bombardment on the dielectric surface. This significantly improves the chemical purity and process stability of the output ion beam while achieving large-area, high-efficiency energy coupling.

[0052] Furthermore, in some embodiments, the longitudinal stiffeners 12 of the window-shaped induction support frame 10 integrate microfluidic cooling circuits. By actively dissipating heat from the edges of the induction cutout window 11 through the stiffeners, not only is the local thermal instability problem during large-area discharge solved, but the flow characteristics of the cooling medium are also used to further absorb the residual parasitic energy on the frame. Thus, together with the power supply network, a stable discharge environment with thermal-electric coupling balance is constructed.

[0053] In some embodiments, the top of the windowed induction support frame 10 is provided with an ion extraction grid 30, and the bottom of the windowed induction support frame 10 is provided with a gas distribution structure 40. The starting feed section 21 and the ending feed section 22 extend in the same direction to the vicinity of the gas distribution structure 40 for electrical connection. The radio frequency ion source device of this embodiment constructs a highly integrated and thermoelectrically separated vertical process path by providing an ion extraction grid 30 at the top of the windowed induction support frame 10, a gas distribution structure 40 at the bottom, and extending the starting feed section 21 and the ending feed section 22 of the multi-turn rectangular spiral coil 20 in the same direction to the vicinity of the bottom gas distribution structure 40 for electrical connection. Because the gas distribution structure 40 is located at the bottom and the extraction grid is located at the top, the process gas can achieve sufficient spatial coupling with the three-dimensional induction electromagnetic field generated by the lateral coil during its upward flow, significantly improving the gas ionization efficiency. The axial uniformity of plasma density; at the same time, the RF feed point is concentrated at the bottom far away from the high-temperature ion extraction zone, and the metal base of the gas distribution structure 40 is used as a natural electrical shielding support. This not only effectively shortens the physical distance between the feed line and the matching network, reducing high-frequency transmission loss and electromagnetic radiation (EMI), but also avoids the failure of electrical interfaces due to temperature rise caused by the heat radiation of the top grid. This greatly optimizes the overall thermal management level and long-term electrical reliability of the device, and realizes the deep synergy of process gas flow field, electromagnetic coupling field and thermodynamic field in a large-area rectangular discharge environment.

[0054] A multi-turn rectangular spiral coil 20 is three-dimensionally wrapped around the outside of the windowed induction support frame 10, and each turn of the multi-turn rectangular spiral coil 20 is respectively arranged across the induction cutout window 11 to radiate an induction electromagnetic field into the internal space through the induction cutout window 11. The multi-turn rectangular spiral coil 20 includes a starting feed section 21 and an ending feed section 22. Both the starting feed section 21 and the ending feed section 22 are led out from a non-centrally symmetrical position on one side of the long side of the multi-turn rectangular spiral coil 20 to the bottom of the windowed induction support frame 10, and one of them is arranged vertically downward from the top layer winding across the remaining turns of the multi-turn rectangular spiral coil 20 to compensate for the radio frequency phase delay of the multi-turn rectangular spiral coil 20 in the long axis direction through an asymmetrical physical path.

[0055] In some embodiments, the multi-turn rectangular spiral coil 20 is wound with a hollow water-cooled copper tube, and the lead-out positions of the initial feed section 21 and the final feed section 22 are located within 1 / 5 to 1 / 3 of the length of one long side. During high-power operation of the radio frequency ion source, the coil will experience a significant temperature rise due to the skin effect and Joule heating effect. By introducing a cooling medium inside the coil, active heat dissipation of the inductive coupling core can be achieved, effectively suppressing the increase in resistivity and inductive reactance drift of the copper tube caused by high temperature. This real-time thermal management mechanism ensures the constancy of the coil's electrical parameters under long-term continuous operation, thereby maintaining the accuracy of impedance matching and avoiding frequency off-target or structural deformation caused by overheating. In a large rectangular cavity, the transmission of radio frequency energy along a long path inevitably produces a phase delay, resulting in an asymmetric distribution of plasma density along the long axis. In this embodiment, setting the lead-out positions of the initial feed section 21 and the final feed section 22 to non-central positions allows for the artificial introduction of a controlled initial phase difference. Combined with the spanning layout of the initial feed section 21, this interval position generates a moderate mutual inductance, providing reverse compensation against the field strength attenuation along the long axis. This "pre-processing at the physical structure level" makes the plasma distribution in the rectangular discharge space more centrosymmetric, solving the problem of insufficient edge coverage in large-area ion sources and significantly improving the lateral uniformity of the output ion beam. Furthermore, the specific setting of the lead-out positions allows the initial and final ends to be led to the bottom in a more compact parallel arrangement. Because the two leads are close in physical space and have opposite current directions, the magnetic fields they generate undergo destructive interference in the far-field region. This structural feature greatly compresses the loop area formed by the high-frequency current, suppressing the radiation interference of radio frequency energy to the external environment from the source. This not only improves energy utilization but also protects the precision vacuum gauges and sensors around the ion source from electromagnetic interference.

[0056] In addition to the equidistant arrangement of the multi-turn rectangular spiral coils 20 shown in the illustration, in other embodiments, the multi-turn rectangular spiral coils 20 can be wound using a non-equidistant spacing process. By reducing the coil turn spacing on the side closer to the ion extraction grid 30, a gradient inductive coupling field is constructed in physical space. This effectively compensates for the magnetic field divergence at the end of the rectangular frame, and in conjunction with the phase compensation function of the feed network, achieves high-precision uniform output of the ion beam throughout the entire region.

[0057] In some embodiments, the multi-turn rectangular spiral coil 20 adopts a smooth arc transition at the corner, and the ratio of the total area of ​​the sensing cutout window 11 to the total area of ​​the sidewall of the windowed sensing support frame 10 is greater than 60%. The multi-turn rectangular spiral coil 20 effectively avoids the severe skin effect and charge accumulation phenomenon caused by the radio frequency current at the sharp corners of the rectangle by using a smooth arc transition at the corners. This eliminates the risk of high voltage breakdown caused by local electric field distortion from a physical perspective, and significantly improves the electrical safety and service life of the coil under high power loading. At the same time, the total area ratio of the induction cutout window 11 of the windowed induction support frame 10 is set to be greater than 60%. While ensuring that the frame has sufficient vacuum mechanical support strength, the conductivity continuity of the metal sidewall in the circumferential direction is broken to the maximum extent. This greatly suppresses the generation of induced eddy currents in the frame itself and the resulting Joule heat loss. This allows the induced electromagnetic field generated by the multi-turn rectangular spiral coil 20 to couple to the internal discharge space through the large area window with extremely high transmittance. Thus, while achieving efficient excitation of large-area rectangular plasma, the ineffective dissipation of energy in the structural components is greatly reduced, ensuring the energy conversion efficiency and thermomechanical stability of the entire radio frequency ion source device under high power density operation.

[0058] This invention achieves the following significant technical effects through the synergy of specific physical structure reconstruction and electromagnetic field coupling mechanisms:

[0059] 1. Deep suppression of energy loss by the window-pane induction support frame

[0060] By setting multiple induction-perforated windows on the sidewalls of the windowed induction support frame and using longitudinal reinforcing ribs for spatial separation, this device physically breaks the closed path of circumferential current in the metal frame under the radio frequency field. This feature can significantly reduce the induced eddy currents generated inside the windowed induction support frame, reduce the Joule heat loss of the metal frame due to the eddy current effect, and thus direct more radio frequency energy to the internal discharge space through the induction-perforated windows, greatly improving the power conversion efficiency in the plasma generation process.

[0061] 2. Physical reconstruction of large-area uniformity using a rectangular stereoscopic sensing architecture

[0062] This device employs a multi-turn rectangular helical coil that surrounds the outside of a window-like induction support frame, with its rectangular geometry precisely matching the spatial shape of the internal discharge chamber. Compared to traditional planar or circular helical coils, this three-dimensional, fully enclosed coupling method ensures deep penetration and uniform coverage of the induced electromagnetic field along its long axis, eliminating edge coverage blind spots during large-area discharge processes and providing a physical basis for obtaining highly uniform rectangular large-area ion beams.

[0063] 3. Dynamic compensation for phase delay derived from non-centrosymmetric co-directional extraction.

[0064] By placing both the initial and final feed sections of the coil at non-centrosymmetric positions along its long side, an asymmetric current path is artificially created. Since radio frequency waves inherently experience phase delay when propagating through a large rectangular coil, the mutual inductance effect generated by this asymmetric layout can counteract the phase fluctuations along the long axis of the coil. This design, which compensates for electromagnetic distortion with an asymmetric structure, ensures spatial consistency of plasma density along the long axis, solving the problem of uneven field distribution commonly found in large-size ion sources.

[0065] 4. Directional regulation of parasitic parameters by vertically downward spanning layout

[0066] The initial feed section, positioned vertically downwards from the top winding across the remaining turns, not only achieves centralized integration of the feed point towards the bottom, but more importantly, this specific crossing path creates controlled distributed parameter coupling between the feed and each turn. This structural feature provides a clear physical reference for lumped parameter compensation in the subsequent feed network, making it possible to precisely balance the potential across the coil terminals via external circuitry. This effectively suppresses high-voltage overshoot, avoids arcing failures at coil corners or insulation supports, and significantly improves the reliability of the equipment under high-power, long-term operation.

[0067] While the aforementioned three-dimensional framework structure and its non-centrosymmetric long-path feed leads offer significant advantages in spatial coupling and mechanical integration, they also present challenges to the circuit. Specifically, this large-size rectangular multi-turn spiral coil exhibits extremely high distributed inductive reactance at radio frequency. Furthermore, the asymmetrical spatial arrangement of the start and end leads introduces complex parasitic parameters and mutual inductance interference. Using traditional general-purpose matching networks can easily lead to excessively high reflected power due to impedance mismatch, and may even cause severe arcing failure at the high-voltage end of the coil, making it difficult for the advanced physical structure to achieve its intended process performance.

[0068] Therefore, this application develops an impedance self-balancing feed network deeply coupled with the aforementioned device. This feed network is not a general impedance transformation tool, but rather, specifically designed for the unique electrical characteristics of rectangular multi-turn coils, it "forcefully balances" the phase deviation and inductive overshoot caused by the physical structure from the underlying electrical logic by introducing lumped parameter compensation branches at both ends of the physical leads. This collaborative design, where "structure creates contradictions, circuit resolves contradictions," not only solves the matching instability problem under high inductive loads but also endows the entire RF ion source system with the outstanding performance of maintaining a stable impedance trajectory "locked" even under extreme power conditions.

[0069] Please see Figure 5 , Figure 5 This is a schematic diagram of the topology of a feed network provided in one embodiment of this application. This feed network can be used in the radio frequency ion source device of the aforementioned embodiments. It includes a first symmetrical compensation branch 61, a second symmetrical compensation branch 62, and a resonant adjustment branch 70.

[0070] The power supply network has an RF power input terminal for receiving high-frequency energy from an external RF power source. The first symmetrical compensation branch 61 and the second symmetrical compensation branch 62 are respectively connected in series at the start and end of the RF ion source coil. Figure 5 The box in ICP represents the radio frequency ion source coil, which is the core load of the inductively coupled plasma (ICP) generation device. The first and second symmetrical compensation branches 62 each contain at least one lumped parameter compensation inductor to build a radio frequency potential balance point on the radio frequency ion source coil and to compensate for the parasitic inductive reactance caused by the asymmetrical arrangement of the radio frequency ion source coil leads.

[0071] In some embodiments, the first compensation inductor L10 in the first symmetrical compensation branch 61 and the second compensation inductor L12 in the second symmetrical compensation branch 62 have equal inductive reactance values ​​and are symmetrically arranged at the output end of the feed network. Since the RF ion source coil has a large distributed inductance, this symmetrical inductance compensation at the output end can construct a stable RF potential balance point within the coil's internal space. This design not only counteracts the mutual inductance imbalance caused by the feed line vertically crossing the winding, but also effectively suppresses the risk of arc breakdown during high-power discharge by reducing the instantaneous potential difference across the coil, ensuring uniform excitation of a large rectangular plasma area. It should be noted that in this embodiment, the core compensation element of the first symmetrical compensation branch 61 and the second symmetrical compensation branch 62 is preferably a lumped parameter inductor (i.e.,... Figure 5(L10 and L12 in the diagram); however, based on the general understanding of those skilled in the art, the first and second symmetrical compensation branches can also be composed of inductor arrays consisting of multiple inductors connected in series, in parallel, or in a mixed manner, or composed of complex impedance matching networks consisting of a combination of inductors and capacitors, in order to achieve the same inductive reactance compensation effect.

[0072] In some embodiments, in the circuit topology of the power supply network, the resonant adjustment branch 70 is connected between the first symmetrical compensation branch 61 and the second symmetrical compensation branch 62. Specifically, as Figure 5 As shown, one end of the third compensation inductor L15 in the resonant adjustment branch 70 is electrically connected to the input side of the first compensation inductor L10, and the other end is electrically connected to the input side of the second compensation inductor L12.

[0073] In a preferred embodiment, the third compensation inductor L15, together with the lumped parameter inductors in the first and second symmetrical compensation branches 62, constitutes a multi-pole resonant network. To achieve dynamic closed-loop impedance tuning, the multi-pole resonant network further includes a tuning capacitor unit configured in the circuit; specifically, the tuning capacitor unit includes a first variable capacitor C10 connected in series on the RF input path, and a second variable capacitor C11 connected across the third compensation inductor L15 and the ground terminal GND. The technical effect of this circuit configuration is that the introduction of the third compensation inductor L15 essentially changes the impedance transformation slope of the first and second variable capacitors (C10, C11) on the complex impedance plane.

[0074] Because the multi-turn rectangular spiral coil 20 used in this invention has a very large distributed inductive reactance, and the load impedance undergoes a drastic nonlinear jump when the plasma transitions from the capacitive coupling mode before ignition to the inductive coupling mode after ignition. By adjusting the capacitances of C10 and C11, and coordinating with the fixed inductive reactance compensation of L10, L12, and L15, the entire feed network exhibits multiple impedance resonant poles near the RF operating frequency. This multi-pole characteristic greatly widens the physical window for impedance matching, enabling the system to adapt to the drastic impedance fluctuations of the multi-turn rectangular spiral coil 20 under different process gas pressures and discharge powers, ensuring that the impedance matching point is always locked within the efficient coupling range, effectively avoiding system failures caused by mismatch and excessive reflected power.

[0075] In some embodiments, the power supply network further includes a phase detection circuit for real-time sampling of the potential difference between the first and second symmetrical compensation branches 62, and adjusting the variable capacitor in the multi-pole resonant network based on the feedback signal generated by the potential difference. Although in Figure 5For simplicity, this diagram is not shown, but in actual installation, it is connected to the output terminals of the first compensation inductor L10 and the second compensation inductor L12 via sampling probes. This circuit acts like a real-time monitor, specifically targeting the phase difference caused by the varying lengths and asymmetrical positions of the rectangular coil leads. When the ion source discharges at high power or changes gas pressure, the voltage phase across the coil drifts. The phase detection circuit immediately senses this unbalanced potential difference signal and transmits it to the control system, causing the two variable capacitors in the drive circuit to automatically rotate and align. Through this real-time feedback adjustment, the power supply network, like automatic frequency tuning, consistently pulls the potential across the coil back to a balanced state. This not only solves the long-standing problem of arcing in large rectangular coils but also ensures uniform plasma emission along its long axis, making the entire ion source system very stable during long-term continuous operation.

[0076] The impedance self-balancing feed network of this invention achieves the following significant technical effects through the deep synergy of a specific circuit topology configuration and a lumped parameter compensation mechanism:

[0077] 1. Compensation for electrical imbalance caused by physical lead asymmetry

[0078] Because the radio frequency ion source device uses a multi-turn rectangular spiral coil with non-centrally symmetrical lead distribution (such as a vertically downward winding layout), there is a significant difference in parasitic inductive reactance between its starting and ending points in the spatial coupling environment. This feeding network artificially constructs a symmetrical radio frequency potential balance point at both ends of the coil by connecting a first and a second symmetrical compensation branch in series at the output end, utilizing the lumped parameters of the first compensation inductor L10 and the second compensation inductor L12 to offset each other. This feature effectively cancels out the phase shift caused by physical path asymmetry and eliminates potential distortion during the ignition stage, thus solving the problem of localized high-voltage arcing and uneven ignition that easily occurs with large-size rectangular coils from an electrical underlying logic perspective.

[0079] 2. The multi-pole resonant architecture significantly widens the matching window.

[0080] This power supply network, through a third compensation inductor L15 connected between the symmetrical compensation branches, together with the first and second variable capacitors C10 and C11, forms a multi-pole resonant network. Compared to traditional single-pole matching circuits, the introduction of the third compensation inductor alters the impedance transformation slope of the capacitor on the complex impedance plane, resulting in multiple mutually coupled resonant poles near the RF operating frequency. This multi-pole characteristic significantly compresses the evolution trajectory of the load impedance, enhances the circuit's tolerance to drastic fluctuations in inductive reactance, and ensures that the system can adapt to the dramatic transition of plasma from weak coupling before ignition to strong inductive coupling after ignition in a large-area rectangular discharge environment. This effectively avoids the risk of impedance matching "off-target" failure and shutdown caused by excessive reflected power.

[0081] 3. Impedance track locking and stability during high-power operation

[0082] By segmenting the massive distributed inductive reactance of the multi-turn rectangular spiral coil using lumped parameter compensation elements (L10, L12, L15), this feed network transforms the originally difficult-to-tunable high-inductive load into a controllable impedance point within the matching circuit's adjustment window. This "impedance trajectory locking" capability ensures that the RF power supply's energy output remains within the high-efficiency coupling range during dynamic changes in process gas pressure and discharge power. Combined with closed-loop feedback implemented by an optional phase detection circuit, the system can correct inductive reactance drift caused by coil temperature rise in real time, significantly improving the process repeatability and long-term operational reliability of the RF ion source system in large-scale industrial production.

[0083] 4. Deep optimization of the electromagnetic environment through destructive magnetic field interference.

[0084] Because the first and second symmetrical compensation branches of the feed network are physically laid out with their starting and ending points parallel to each other, and the phase of the RF current in the two branches is controlled, the instantaneous magnetic fields generated by the two feed leads in the external space undergo destructive interference. This synergistic design of the structure and circuit greatly reduces the loop area formed by the high-frequency current, suppressing stray electromagnetic interference (EMI) radiated radially from the feed circuit at its source. This not only significantly improves the effective utilization rate of RF energy but also creates a clean electromagnetic environment for vacuum gauges, flow meters, and precision control sensors around the ion source, reducing the shielding design difficulty and manufacturing cost of the entire system.

[0085] This application also provides a radio frequency ion source system, which includes the radio frequency ion source device and the feed network of the aforementioned embodiments. The feed network is electrically connected between the radio frequency power supply and the radio frequency ion source device. The feed network compensates for the inductance by lumped parameters to offset the impedance imbalance caused by the non-centrally symmetrical position of the multi-turn rectangular spiral coil.

[0086] In some embodiments, the feed network is integrated into the bottom of the RF ion source device and shares an electrical shield with the gas distribution structure at the bottom of the windowed induction support frame. By directly integrating the feed network into the bottom of the RF ion source device, the physical connection distance between the output end of the feed network and the starting and ending sections of the multi-turn rectangular spiral coil is greatly shortened, effectively reducing the distributed inductance and parasitic resistance loss of high-frequency RF energy in the transmission path, thereby significantly improving the overall energy conversion efficiency of the system. At the same time, utilizing the gas distribution structure at the bottom of the windowed induction support frame as a natural mechanical support and electrical reference, and sharing an electrical shield with the feed network, not only achieves a highly compact structure and saves external installation space, but more importantly, this shared shield design constructs a fully enclosed electromagnetic protection ring. The shielded environment effectively confines high-frequency electromagnetic radiation within the power supply network and stray field strength at the coil leads to the shielded space, suppressing electromagnetic interference (EMI) from the source to the precision sensors and vacuum monitoring components around the ion source. Furthermore, this bottom-integrated layout cleverly utilizes the relatively low temperature environment of the bottom gas distribution area, keeping sensitive components such as lumped parameter inductors in the power supply network away from the high-temperature radiation zone of the top ion extraction grid. This achieves a scientifically designed thermoelectric separation layout, significantly reducing the risk of parameter drift in electrical components due to temperature rise, and ensuring the impedance matching stability and long-term operational reliability of the RF ion source system under continuous, high-power operation.

[0087] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0088] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A radio frequency ion source device, characterized in that, include: A windowed induction support frame, the internal space of which serves as a rectangular discharge chamber; The sidewall of the windowed inductive support frame is provided with multiple inductive cutout windows, and adjacent inductive cutout windows are separated by longitudinal reinforcing ribs, so as to reduce the circumferential inductive eddy current of the windowed inductive support frame while maintaining structural strength. A multi-turn rectangular spiral coil is three-dimensionally wrapped around the outside of the windowed induction support frame, and each turn of the multi-turn rectangular spiral coil is respectively arranged across the induction cutout window to radiate an induction electromagnetic field into the internal space through the induction cutout window. The multi-turn rectangular spiral coil includes a starting feed section and an ending feed section. Both the starting feed section and the ending feed section extend from a non-centrally symmetrical position on one long side of the multi-turn rectangular spiral coil to the bottom of the windowed induction support frame. One section extends vertically downward from the top winding across the remaining turns of the multi-turn rectangular spiral coil to compensate for the radio frequency phase delay of the multi-turn rectangular spiral coil in the long axis direction through an asymmetric physical path.

2. The radio frequency ion source device according to claim 1, characterized in that: The multi-turn rectangular spiral coil is wound with hollow water-cooled copper tube, and the lead-out positions of the starting power supply section and the ending power supply section are located within 1 / 5 to 1 / 3 of the length of the long side of one side.

3. The radio frequency ion source device according to claim 1, characterized in that: The multi-turn rectangular spiral coil has a smooth arc transition at the corner, and the ratio of the total area of ​​the induction hollow window to the total area of ​​the side wall of the windowed induction support frame is greater than 60%.

4. The radio frequency ion source device according to claim 1, characterized in that: The top of the windowed induction support frame is provided with an ion extraction grid, and the bottom of the windowed induction support frame is provided with a gas distribution structure. The starting power supply section and the ending power supply section extend in the same direction to the vicinity of the gas distribution structure for electrical connection.

5. A feed network for a radio frequency ion source apparatus as claimed in any one of claims 1 to 4, characterized in that, include: The first symmetrical compensation branch and the second symmetrical compensation branch are respectively connected in series at the start and end of the radio frequency ion source coil; The resonant adjustment branch is connected between the first and second symmetrical compensation branches; The first and second symmetrical compensation branches each include at least one lumped parameter compensation inductor to construct a radio frequency potential balance point on the radio frequency ion source coil and to compensate for the parasitic inductance caused by the asymmetrical arrangement of the leads of the radio frequency ion source coil.

6. The power supply network according to claim 5, characterized in that: The first compensation inductor in the first symmetrical compensation branch and the second compensation inductor in the second symmetrical compensation branch have equal inductive reactance values ​​and are symmetrically arranged at the output end of the power supply network.

7. The power supply network according to claim 5, characterized in that: The resonant adjustment branch includes a third compensation inductor, which together with the first and second symmetrical compensation branches constitutes a multi-pole resonant network.

8. The power supply network according to claim 7, characterized in that: The power supply network also includes a phase detection circuit, which is used to sample the potential difference between the first and second symmetrical compensation branches in real time, and adjust the variable capacitor in the multi-pole resonant network according to the feedback signal generated by the potential difference.

9. A radio frequency ion source system characterized by, include: The radio frequency ion source device as described in any one of claims 1-4; The power supply network as described in any one of claims 5-8, wherein the power supply network is electrically connected between the radio frequency power supply and the radio frequency ion source device; The power supply network compensates for the inductance by using lumped parameters to offset the impedance imbalance caused by the non-centrally symmetrical position of the multi-turn rectangular spiral coil.

10. The radio frequency ion source system according to claim 9, characterized in that: The power supply network is integrated at the bottom of the radio frequency ion source device and shares an electrical shield with the gas distribution structure at the bottom of the windowed induction support frame.

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