Tuning device for resonant impedance, tuning method and microwave plasma processing device

Abstract

This invention discloses a tuning device, tuning method, and microwave plasma processing apparatus for resonant impedance. The tuning device includes: a transmission sleeve fitted around the periphery of a first antenna, wherein the first antenna is axially inserted into the interior of a resonant cavity; a tuning element coaxially fitted around the periphery of the transmission sleeve, its end face perpendicular to the first antenna; and a motor located outside the resonant cavity, connected to the first end of the transmission sleeve extending out of the resonant cavity, used to drive the tuning element axially through the transmission sleeve, adjusting the axial position of the capacitive load generated by the tuning element within the resonant cavity, thereby adjusting the port input impedance of the resonant cavity. This invention not only significantly reduces the risk of debris generation and micro-discharge in a vacuum environment, but also improves tuning accuracy and adjustment sensitivity without altering the core structure of the cavity or disrupting the plasma distribution pattern, thus ensuring the stability of the process state and significantly improving the uniformity and consistency of thin film deposition.

Description

Technical Field

[0001] This invention relates to the technical field of semiconductor manufacturing, and specifically to a resonant impedance tuning device, a microwave plasma processing device, a resonant impedance tuning method, and a computer-readable storage medium. Background Technology

[0002] The process stability of microwave plasma chemical vapor deposition (MPCVD) equipment hinges on the impedance matching accuracy of the resonant cavity. Current mainstream tuning methods primarily include external waveguide tuning and cavity structure tuning. The former, currently the dominant matching method for MPCVD equipment, involves installing components such as three pins and EH-impedance matching devices in the front-end waveguide link of the resonant cavity. Impedance compensation of the waveguide transmission link is achieved by adjusting the insertion depth of the pins and the position of the short-circuit piston. The latter method fine-tunes the resonant cavity parameters by adjusting the core structural dimensions of the cavity, such as the insertion depth of the antenna within the resonant cavity, the position of the short-circuit piston at the bottom of the cavity, and the height of the sample stage, thereby achieving impedance matching adjustment.

[0003] However, among the two tuning methods mentioned above, the former uses a passive compensation structure for the link, which cannot directly correct the deviation of the actual impedance of the electromagnetic field inside the cavity. Its tuning accuracy and adjustment sensitivity are limited, and it suffers from insufficient control depth and matching lag. Furthermore, the tuning device is prone to arcing due to electric field concentration, causing its reflected power to drift under high-power conditions, making it difficult to meet the tuning requirements of high power and high precision. The latter method, on the other hand, requires modifications to the core cavity structure, such as the antenna, piston, and sample stage, which would damage the inherent TM of the resonant cavity. 010 The distribution of the field pattern causes a shift in the plasma morphology, affecting the stability and uniformity of thin film deposition.

[0004] In addition, there is a tuning method that uses a threaded lead screw to drive the impedance matching controller to move within the resonant cavity. However, the resonant cavity of MPCVD is a strong electromagnetic field environment. If traditional transmission components such as lead screws and connecting rods are built into it, it will not only interfere with the distribution of the electromagnetic field within the cavity and cause concentrated electric field arcing, but the transmission components are also prone to generating metal debris due to friction, which will contaminate the cavity and induce micro-discharge arcing. Therefore, it cannot meet the requirements of high-power, long-term continuous operation.

[0005] To address the aforementioned problems in existing technologies, there is an urgent need in this field for a resonant impedance tuning technique that can not only significantly reduce the risk of debris generation and micro-discharge in a vacuum environment, but also improve tuning accuracy and adjustment sensitivity without altering the core structure of the cavity or disrupting the plasma distribution pattern. This would ensure the stability of the process state and significantly improve the uniformity and consistency of thin film deposition. Summary of the Invention

[0006] The following provides a brief overview of one or more aspects to offer a basic understanding of them. This overview is not an exhaustive summary of all conceived aspects, nor is it intended to identify key or decisive elements of all aspects, nor to define the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed descriptions that follow.

[0007] To overcome the aforementioned deficiencies in the prior art, this invention provides a resonant impedance tuning device, a microwave plasma processing device, a resonant impedance tuning method, and a computer-readable storage medium. These devices not only significantly reduce the risk of debris generation and micro-discharge in a vacuum environment, but also improve tuning accuracy and adjustment sensitivity without altering the core cavity structure or disrupting the plasma distribution pattern. This ensures the stability of the process state and significantly enhances the uniformity and consistency of thin film deposition.

[0008] Specifically, the resonant impedance tuning device provided according to the first aspect of the present invention includes: a transmission sleeve sleeved around the periphery of a first antenna, wherein the first antenna is axially inserted into the interior of a resonant cavity; a tuning element coaxially sleeved around the periphery of the transmission sleeve, the end face of which is perpendicular to the first antenna; and a motor located outside the resonant cavity and connected to a first end of the transmission sleeve extending out of the resonant cavity, for driving the tuning element to move axially through the transmission sleeve, adjusting the axial position of the capacitive load generated by the tuning element in the resonant cavity, thereby adjusting the port input impedance of the resonant cavity.

[0009] Furthermore, in some embodiments of the present invention, the transmission sleeve includes a sleeve structure made of metal, and the tuning element includes a coupling ring made of metal, the inner ring of which is coaxially fixed to the outer surface of the transmission sleeve, and the ring surface of the coupling ring is perpendicular to the first antenna.

[0010] Furthermore, in some embodiments of the present invention, the inner ring of the coupling ring is fixed to the outer surface of the transmission sleeve by welding, and after welding, the weld and the ring edge of the coupling ring are ground and polished to remove weld beads, burrs and sharp corners.

[0011] Furthermore, in some embodiments of the present invention, the transmission sleeve and the first antenna are in clearance fit, and the first gap between them is configured to allow the transmission sleeve to move axially without rubbing against the first antenna.

[0012] Furthermore, in some embodiments of the present invention, the resonant cavity further includes: a quartz window for isolating the resonant cavity from the reaction cavity located below the resonant cavity; and a second antenna located above the quartz window and below the first antenna, forming an electromagnetic coupling with the first antenna to receive microwave energy transmitted by the first antenna and radiate it to the reaction cavity below, wherein a through slot is formed at the center of the second antenna to allow the transmission sleeve to move axially within the through slot.

[0013] Furthermore, in some embodiments of the present invention, the second antenna is a loop antenna with a radial radius greater than that of the first antenna, so that the microwave radiation coverage of the second antenna is greater than that of the first antenna.

[0014] Furthermore, in some embodiments of the present invention, the through groove and the transmission sleeve are fitted with a clearance, and the second gap between the two is provided with a preset size to allow for thermal deformation compensation of the transmission sleeve.

[0015] Furthermore, in some embodiments of the present invention, the tuning device further includes: a microwave parameter measuring instrument for acquiring microwave reflection parameters at the input port of the resonant cavity; and a controller configured to: acquire the microwave reflection parameters at the input port of the resonant cavity; determine whether the microwave reflection parameters are within a target range; adjust the axial position of the tuning element to adjust the input port impedance of the resonant cavity in response to the microwave reflection parameters being outside the target range; and lock the position of the tuning element to complete impedance adjustment in response to the microwave reflection parameters being within the target range.

[0016] Furthermore, the microwave plasma processing apparatus provided according to a second aspect of the present invention includes: a waveguide disposed above a resonant cavity for feeding microwaves into the resonant cavity; a first antenna axially inserted inside the resonant cavity for axially conducting the microwaves into the resonant cavity; a resonant impedance tuning device provided in the first aspect of the present invention for adjusting the input port impedance of the resonant cavity to match the characteristic impedance of the waveguide; and a reaction cavity located below the resonant cavity for performing microwave plasma processing reactions.

[0017] Furthermore, the resonant impedance tuning method provided by the third aspect of the present invention, implemented via the resonant impedance tuning device provided by the first aspect of the present invention, includes the following steps: acquiring microwave reflection parameters at the input port of the resonant cavity; determining whether the microwave reflection parameters are located within a target range; adjusting the axial position of a tuning element to adjust the input port impedance of the resonant cavity in response to the microwave reflection parameters being outside the target range; and locking the position of the tuning element in response to the microwave reflection parameters being within the target range to complete impedance adjustment.

[0018] Furthermore, in some embodiments of the present invention, the step of adjusting the axial position of the tuning element to adjust the input port impedance of the resonant cavity in response to the microwave reflection parameter being outside the target range includes: performing closed-loop fine-tuning of the axial position of the tuning element in response to the microwave reflection parameter being outside the target range in a first threshold range; and performing open-loop coarse-tuning of the axial position of the tuning element in response to the microwave reflection parameter being outside the target range in a second threshold range, wherein the mismatch degree of the second threshold range is higher than that of the first threshold range.

[0019] Furthermore, according to a fourth aspect of the present invention, a computer-readable storage medium is provided having computer instructions stored thereon. When the computer instructions are executed by a processor, the above-described method for tuning the resonant impedance provided in the third aspect of the present invention is implemented. Attached Figure Description

[0020] The above-described features and advantages of the present invention will be better understood after reading the following detailed description of embodiments of the present disclosure in conjunction with the accompanying drawings. In the drawings, components are not necessarily drawn to scale, and components having similar related characteristics or features may have the same or similar reference numerals.

[0021] Figure 1 A cross-sectional structural schematic diagram of a microwave plasma processing apparatus provided according to some embodiments of the present invention is shown.

[0022] Figure 2 for Figure 1 The diagram shows a top view of the microwave plasma processing device.

[0023] Figure 3 A flowchart of a method for tuning a resonant impedance according to some embodiments of the present invention is shown.

[0024] Figure 4 A flowchart of a method for tuning a resonant impedance according to other embodiments of the present invention is shown.

[0025] Figure 5A A schematic diagram of the simulation results of the cavity structure without coupling ring in the prior art and its microwave reflection parameters is shown.

[0026] Figure 5B A schematic diagram of simulation results of a cavity structure with a coupling ring and its microwave reflection parameters provided according to some embodiments of the present invention is shown.

[0027] Figure 6 A structural block diagram of a controller provided according to some embodiments of the present invention is shown.

[0028] Figure label: 10. Microwave plasma processing device; 100 waveguide; 110 Top through slot; 200 resonant cavity; 210 First antenna; 211 cooling water channel; 220 Second antenna; 221 Bottom through groove; 230 Quartz window; 300 tuning device; 310 Transmission sleeve; 320 tuning element; 330 motor; 331 Transmission mechanism; 340 controller; 341 Memory; 342 processor; 400 reaction chamber; Steps S310~S340 Detailed Implementation

[0029] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Although the description of the present invention is presented in conjunction with preferred embodiments, this does not mean that the features of the invention are limited to these embodiments. On the contrary, the purpose of describing the invention in conjunction with embodiments is to cover other options or modifications that may be derived based on the claims of the present invention. To provide a thorough understanding of the invention, many specific details will be included in the following description. The invention may also be implemented without using these details. Furthermore, to avoid confusion or obscuring the focus of the invention, some specific details will be omitted in the description.

[0030] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; 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; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0031] Furthermore, the terms "upper," "lower," "left," "right," "top," "bottom," "horizontal," and "vertical" used in the following description should be understood as the orientations shown in the relevant paragraphs and accompanying drawings. These relative terms are for illustrative purposes only and do not imply that the described apparatus must be manufactured or operated in a specific orientation, and therefore should not be construed as limiting the invention.

[0032] It is understood that although terms such as "first," "second," and "third" may be used herein to describe various components, regions, layers, and / or parts, these components, regions, layers, and / or parts should not be limited by these terms, and these terms are only used to distinguish different components, regions, layers, and / or parts. Therefore, the first components, regions, layers, and / or parts discussed below may be referred to as second components, regions, layers, and / or parts without departing from some embodiments of the present invention.

[0033] As mentioned above, existing mainstream tuning methods mainly include external waveguide tuning and cavity structure tuning. Of these two methods, the former uses a passive link compensation structure, which cannot directly correct the deviation of the actual impedance of the electromagnetic field within the cavity. Its tuning accuracy and adjustment sensitivity are limited, and it suffers from insufficient control depth and matching lag. Furthermore, the tuning device is prone to arcing due to electric field concentration, resulting in easy power drift under high-power conditions, making it difficult to meet the high-power, high-precision tuning requirements. The latter method, on the other hand, requires modifications to the core cavity structure, such as the antenna, piston, and sample stage, which would damage the inherent TM of the resonant cavity. 010 The distribution of the field pattern causes a shift in the plasma morphology, affecting the stability and uniformity of thin film deposition.

[0034] In addition, there is a tuning method that uses a threaded lead screw to drive the impedance matching controller to move within the resonant cavity. However, the resonant cavity of MPCVD is a strong electromagnetic field environment. If traditional transmission components such as lead screws and connecting rods are built into it, it will not only interfere with the distribution of the electromagnetic field within the cavity and cause concentrated electric field arcing, but the transmission components are also prone to generating metal debris due to friction, which will contaminate the cavity and induce micro-discharge arcing. Therefore, it cannot meet the requirements of high-power, long-term continuous operation.

[0035] To address the aforementioned problems in the prior art, this invention provides a resonant impedance tuning device, a microwave plasma processing device, a resonant impedance tuning method, and a computer-readable storage medium. These not only significantly reduce the risk of debris generation and micro-discharge in a vacuum environment, but also improve tuning accuracy and adjustment sensitivity without altering the core cavity structure or disrupting the plasma distribution pattern. This ensures the stability of the process state and significantly enhances the uniformity and consistency of thin film deposition.

[0036] In some non-limiting embodiments, the resonant impedance tuning device provided in the first aspect of the present invention can be configured in the microwave plasma processing device provided in the second aspect of the present invention and used to implement the resonant impedance tuning method provided in the third aspect of the present invention.

[0037] The working principle of the resonant impedance tuning device described above will be described below with reference to some examples of microwave plasma processing devices and resonant impedance tuning methods. Those skilled in the art will understand that these examples of microwave plasma processing devices and resonant impedance tuning methods are merely non-limiting embodiments provided by the present invention, intended to clearly demonstrate the main concepts of the invention and provide specific solutions convenient for public implementation, rather than limiting all operating modes or functions of the resonant impedance tuning device. Similarly, the resonant impedance tuning device is also only one non-limiting embodiment provided by the present invention, and does not limit all operating modes or functions of these microwave plasma processing devices, or the implementing entities of each step in the resonant impedance tuning method.

[0038] Please combine Figure 1 and Figure 2 A shared understanding. Figure 1 A schematic diagram of a semiconductor process apparatus provided according to some embodiments of the present invention is shown. Figure 1 A cross-sectional structural schematic diagram of a microwave plasma processing apparatus provided according to some embodiments of the present invention is shown. Figure 2 for Figure 1 The diagram shows a top view of the microwave plasma processing device.

[0039] like Figure 1 and Figure 2 As shown, in some embodiments of the present invention, the microwave plasma processing device 10 mainly includes a waveguide 100, a resonant cavity 200, a resonant impedance tuning device 300, and a reaction cavity 400.

[0040] Specifically, waveguide 100 is positioned above resonant cavity 200 to feed microwaves into resonant cavity 200. Resonant cavity 200 is the main space where microwaves resonate, and is typically a cylindrical metal cavity. A first antenna 210 is axially inserted inside resonant cavity 200 to conduct microwaves axially into resonant cavity 200. For example, as... Figure 1 As shown, the first antenna 210, serving as the central antenna, is inserted axially into the resonant cavity 200 from the waveguide 100 side, thereby guiding the microwaves fed into the waveguide 100 along the antenna axis to the lower region of the resonant cavity 200. The tuning device 300 is used to adjust the input port impedance of the resonant cavity 200 to match it with the characteristic impedance of the waveguide, thereby achieving efficient coupling of microwave energy.

[0041] The reaction chamber 400 is located below the resonant cavity 200 and is sealed and separated from the resonant cavity 200 by a quartz window 230. The reaction chamber 400 is a vacuum clean environment used for microwave plasma process reactions. This reaction chamber 400 can adapt to the timing requirements of various thin film preparation processes such as plasma-enhanced chemical vapor deposition (PECVD), atomic layer deposition (ALD), and metal-organic chemical vapor deposition (MOCVD), and can be configured with corresponding structures and accessories, which are not limited here. Exemplarily, in this embodiment, microwave energy is radiated into the reaction chamber 400 through the first antenna 210, which excites the process gas inside the chamber to generate plasma, enabling microwave plasma process reactions such as diamond thin film on the wafer surface.

[0042] In some alternative embodiments, a second antenna 220 may be included above the quartz window 230 and below the first antenna 210. The second antenna 220 is electromagnetically coupled to the first antenna 210 to receive microwave energy transmitted by the first antenna 210 and radiate it into the reaction cavity 400 below. Exemplarily, the second antenna 220 may be a loop antenna (similar to a cylinder). After receiving the energy, the second antenna 220 radiates it symmetrically into the reaction cavity 400 in a ring-like manner, forming a circumferentially uniform electric field on the wafer plane within the reaction cavity 400, thereby balancing the plasma density distribution and temperature distribution.

[0043] Since the first antenna 210 is vertically inserted into the center of the resonant cavity 200, its radiated energy is mainly concentrated near the axis, thus limiting its radial coverage. Optionally, the radial radius of the annular second antenna 220, which cooperates with the first antenna 210, can be larger than that of the first antenna 210. When the two form electromagnetic coupling, the microwave radiation coverage of the second antenna 220 is greater than that of the first antenna 210. In this embodiment, the second antenna 220 not only radially extends the radiation boundary, expanding the microwave energy coverage to accommodate large-size substrates, but also supplements the peripheral radiated energy of the central first antenna 210, making the field strength distribution from the wafer center to the edge more gradual, avoiding excessively strong electric field in the central region and insufficient energy in the edge region, thereby improving the radial uniformity of plasma density and the consistency of film thickness. Furthermore, increasing the radial radius of the second antenna 220 can also shift the coupling area between the first antenna 210 and the second antenna 220 outwards, avoiding excessive concentration of the electric field near the axis and reducing the risk of micro-discharge and arcing under high-power conditions.

[0044] Continue as Figure 1 As shown, in some embodiments of the present invention, the resonant impedance tuning device 300 mainly includes a transmission sleeve 310, a tuning element 320, and a motor 330.

[0045] Specifically, the transmission sleeve 310 is sleeved around the periphery of the first antenna 210. The tuning element 320 is coaxially sleeved around the periphery of the transmission sleeve 310, with its end face perpendicular to the first antenna 210. The motor 330 is located outside the resonant cavity 200 and connected to the first end of the transmission sleeve 310 that extends out of the resonant cavity 200. It is used to drive the tuning element 320 to move axially through the transmission sleeve 310, thereby adjusting the axial position of the capacitive load generated by the tuning element 320 in the resonant cavity 200, so as to adjust the port input impedance of the resonant cavity 200.

[0046] For example, such as Figure 1 and Figure 2 As shown, after the transmission sleeve 310 extends out of the waveguide 100, it is mechanically connected to the shaft of the motor 330 above the waveguide 100 via the transmission mechanism 331. The rotation of the motor 330 can drive the transmission sleeve 310 to achieve axial linear displacement. The tuning element 320 includes a coupling ring made of metal.

[0047] In this embodiment, the tuning element 320, the first antenna 210, and the inner wall of the resonant cavity 200 form a space capacitance, generating a capacitive loading effect. Without the tuning element 320 (e.g., a coupling ring), the resonant cavity 200 has its inherent resonant frequency, determined by the cavity's physical dimensions (e.g., diameter, height) and operating mode. After the tuning element 320 is added, the aforementioned space capacitance is additionally introduced into the equivalent circuit of the resonant cavity 200, forming a capacitive loading. Loading indicates the introduction of an additional reactive element into the original resonant system. Capacitive loading means that a capacitor (capacitive reactance) is introduced, rather than an inductor (inductive reactance). By adding the tuning element 320, the electrical characteristics of the cavity can be effectively changed through the space capacitance without altering the physical dimensions of the resonant cavity 200.

[0048] From a microwave engineering perspective, the resonant cavity 200 can be equivalent to an LC resonant circuit. Without the tuning element 320 (e.g., a coupling ring), this LC resonant circuit includes: the cavity's equivalent inductance L0 + equivalent capacitance C0, and a resonant frequency of... With the introduction of a tuning element 320 (e.g., a coupling ring), the LC resonant circuit comprises: equivalent inductance L0 + equivalent capacitance C0 + additional capacitance C. load The resonant frequency is Therefore, by adding this tuning element 320, it is equivalent to introducing additional capacitive reactance, thus changing the equivalent electrical length and coupling impedance of the resonant cavity 200. Furthermore, due to C... load Greater than 0, therefore f < f 0 Adding the tuning element 320 can also achieve the effect of shifting the resonant frequency downward.

[0049] Furthermore, since the size of the space capacitance depends on the relative positions and overlap area between the conductors, when the tuning element 320 (e.g., the coupling ring) moves axially, its coupling relationship with the first antenna 210 changes at different positions, its distance from and overlap area at different heights of the cavity wall changes, and the electromagnetic coupling strength with the waveguide feed end and the second antenna 220 also changes accordingly. These changes, when combined, will cause C... load The coupling impedance changes continuously with the axial position of the tuning element 320, thereby enabling continuous adjustment of the port input impedance. Furthermore, due to the periodic resonance characteristics of microwaves, the combined reactance formed by the tuning element 320 and the cavity inductance differs at different axial positions. Therefore, there exists an optimal position where the combined reactance precisely matches the waveguide characteristic impedance (e.g., 50Ω), ensuring that the microwave reflection parameters reach the target range.

[0050] In the above embodiment, a capacitive loading tuning device 300 based on a coaxial tuning element 320 is added inside the resonant cavity. A single tuning element 320 (e.g., a coupling ring) is coaxially fitted onto the outer wall of the transmission sleeve 310 surrounding the central first antenna 210. This coaxial single-ring structure possesses 360° rotational symmetry and good circumferential symmetry, enabling a uniform and pure distribution of the main mode field within the cavity. This effectively suppresses cluttered mode standing waves and ensures electromagnetic field quality and equipment operational stability under high-power conditions.

[0051] Adding multiple tuning elements 320, such as multiple coupling rings on the transmission sleeve 310, would result in excessive capacitive loading, compressing the impedance matching range. Furthermore, the mutual coupling between multiple rings would distort the electromagnetic field and excite heterogeneous modes, thereby disrupting process uniformity. A multi-ring scheme was used for verification during simulations, but the simulation results showed no significant tuning advantage and a substantial increase in the probability of the aforementioned problems occurring.

[0052] In the embodiments provided by this invention, the transmission sleeve 310 includes a sleeve structure made of metal. If conventional transmission components, such as lead screws or connecting rods, are used to connect the external motor 330 and the tuning element 320, a lead screw or connecting rod will inevitably be introduced into the resonant cavity 200. Taking the lead screw as an example, its threads have many sharp structures. A high-intensity, high-frequency electric field exists within the microwave resonant cavity, and the sharp metal locations will generate a field concentration effect, leading to a sharp increase in local field strength, resulting in microwave arcing and discharge, damaging cavity components. Furthermore, the lead screw and connecting rod slide or rotate directly within the resonant cavity 200, causing friction and scraping between the metal parts, which will shed tiny metal fragments. This not only contaminates the cavity environment but also induces arcing under the electric field.

[0053] Furthermore, if a metal rod is used as the transmission component, since the resonant cavity 200 has a central axisymmetric structure and the first antenna 210 is the axis reference, the metal rod suspending the tuning element 320 on one side will deviate from the central axis of the cavity, thus disrupting the coaxial symmetry boundary of the cavity. The high-frequency electric field inside the cavity will shift towards the metal rod on one side, resulting in severe distortion of the electric field distribution. This directly changes the inherent resonant field distribution of the cavity, thereby disrupting the plasma homogeneity within the lower reaction cavity 400 and worsening the process stability. Moreover, the rod's own weight and movement gaps can easily cause the metal rod to sway eccentrically, intermittently scraping against the antenna or cavity wall, leading to the risk of metal debris and indirect sparking.

[0054] In this embodiment of the invention, a smooth, complete cylindrical sleeve structure is used as the intermediate transmission carrier. The sleeve structure not only has continuous, smooth arc surfaces for both its outer circumference and inner hole, without threads, sharp corners, or serrated edges, but it also coaxially fits around the first antenna 210, with a smooth transition between the sleeve wall and the antenna. There are no sharp points where the electric field concentrates, and the strong electric field inside the cavity will not form localized extremely high field strengths on the sleeve surface, thus eliminating the risk of microwave arcing at its source. Furthermore, the sleeve is a complete cylinder, coaxially and completely enclosing the first antenna 210, exhibiting 360° circumferential symmetry. Therefore, the transmission sleeve 310 will not disrupt the axisymmetric electric field distribution of the cavity during movement, preventing localized electric field distortion and interference with plasma morphology, resulting in high tuning linearity.

[0055] In addition, such as Figure 1 As shown, the motor 330 and transmission mechanism 331 are located outside the resonant cavity 200. In this direct-drive tuning element lifting drive device, the upper end of the transmission sleeve 310 extends through the waveguide 100, and the corresponding lead screw, transmission pair, and other sliding friction structures are all arranged outside the waveguide 100, completely isolated from the cavity of the resonant cavity 200. Since there are no complex transmission components inside the resonant cavity 200, the risk of debris generation and micro-discharge in a vacuum environment can be significantly reduced, enabling stable automatic and precise control of the tuning element 320's position under strong electromagnetic field conditions, making it suitable for high-power, long-term continuous operation scenarios.

[0056] Furthermore, the transmission sleeve 310 and the first antenna 210 are clearance-fitted. The first gap between them is configured to allow the transmission sleeve 310 to move axially without friction with the first antenna 210. The transmission sleeve 310 is a complete cylinder that encloses the first antenna 210, and the large-area smooth cylindrical surfaces of the two are clearance-fitted. When the transmission sleeve 310 moves axially, it slides uniformly, without local point contact or hard scraping with the first antenna 210. Compared with the transmission friction caused by point contact in traditional lead screws, this embodiment can ensure that when the transmission sleeve 310 drives the tuning element 320 to move axially, there is no metal friction inside the cavity throughout the entire process. This avoids local electric field distortion and the risk of metal debris and arcing inside the cavity.

[0057] Continue as Figure 1As shown, the coupling ring, coaxial with the transmission sleeve 310, always maintains a horizontal surface and is perpendicular to the first antenna 210. If the coupling ring (i.e., the tuning element 320) becomes skewed during the axial displacement of the transmission sleeve 310, the eccentricity of the coupling ring will not only cause the ring to scrape against the first antenna 210 on one side during the lifting and lowering of the transmission sleeve 310, generating metal debris that contaminates the vacuum cavity, but will also cause uneven circumferential gaps between the ring and the first antenna 210 and the cavity wall. This will result in a highly concentrated electric field at areas with excessively small gaps, which can easily lead to frequent micro-discharges and intracavity arcing under high-power microwaves, damaging the wafer and the cavity. Furthermore, the eccentricity of the coupling ring will also cause circumferential asymmetry in the capacitive loading amount during its axial movement, making it impossible to accurately stabilize to the target range when adjusting the microwave reflection parameters later.

[0058] To address this, the inner ring of the coupling ring can be coaxially fixed to the outer surface of the transmission sleeve 310. Since both the coupling ring and the transmission sleeve 310 are metal components, and their relative positions do not require adjustment, alternatively, the inner ring of the coupling ring can be welded to the outer surface of the transmission sleeve 310 to maintain strict coaxiality. The coupling ring will then move axially synchronously with the transmission sleeve 310. Furthermore, after welding, the weld seam and the edges of the coupling ring can be ground and polished to remove weld beads, burrs, and sharp corners, ensuring a smooth surface transition and eliminating electric field concentration points at gaps and edges, thereby mitigating the risk of micro-discharge and arcing under high-power conditions.

[0059] In the embodiments provided by the present invention, the axial displacement of the tuning element 320 (e.g., a coupling ring) driven by the transmission sleeve 310 can change the axial position of the internal loading within the cavity, thereby continuously adjusting the reactive component of the cavity input impedance and gradually matching the input port impedance with the waveguide characteristic impedance. This adjustment process does not disrupt the cavity's intrinsic field distribution or plasma morphology throughout.

[0060] like Figure 1 As shown, in some embodiments, the outer surface of the first antenna 210 may be provided with a water inlet hole and a water return hole. The bottom of the water inlet hole and the water return hole are laterally connected to form a U-shaped cooling water channel 211 with an axial direction. Sealing grooves and high-pressure resistant O-rings may be provided at the outer ends of the two holes to tighten the joint and achieve static sealing. Cooling water (or other coolant) is introduced into the cooling water channel 211. The Joule heat of the first antenna 210 is removed by the circulating flow of the cooling water, thereby suppressing the temperature rise of the first antenna 210, reducing its thermal deformation and fire risk, and thus improving the stability during high-power operation.

[0061] Continue as Figure 1As shown, in some embodiments, a bottom through-slot 221 can be formed at the center of the second antenna 220 to allow the transmission sleeve 310 to move axially within the slot. Exemplarily, coaxial cylindrical top through-slot 110 and cylindrical bottom through-slot 221 can be machined in the top waveguide 100 and the bottom second antenna 220, respectively. When the transmission sleeve 310 moves axially upward, its top can extend out of the top through-slot 110, and when it moves axially downward, its bottom can extend into the bottom through-slot 221, thereby allowing the transmission sleeve 310 to slide freely axially along the slot. During the axial displacement of the transmission sleeve 310, it will not cause the second antenna 220 to move; that is, the position of the second antenna 220 remains stable. Therefore, the axial distance between the second antenna 220 and the quartz window 230 is constant, thereby avoiding impedance mismatch and electric field distortion within the cavity.

[0062] Since the second antenna 220 is located above the quartz window 230, the axial distance between it and the quartz window 230 determines the coupling strength of microwave energy radiated from the second antenna 220 to the reaction cavity 400, the coupling relationship of the electromagnetic field between the second antenna 220 and the other side of the quartz window 230 (i.e., the reaction cavity side), and the reference value of the input impedance of the resonant cavity 200. This axial distance is precisely adjusted during equipment assembly so that the second antenna 220 is in a basic matched position without coupling ring adjustment. The capacitive loading tuning of the tuning element 320 (e.g., the coupling ring) is fine-tuned based on this reference. If the axial distance between the second antenna 220 and the quartz window 230 changes, it is equivalent to introducing an additional impedance disturbance source during the tuning process, resulting in uncertain tuning direction and impedance mismatch within the cavity. Furthermore, the second antenna 220 is the terminating element for radiating microwaves to the reaction cavity 400, and the electric field distribution between it and the quartz window 230 is extremely sensitive to the spacing. The change in the axial distance between the two will further lead to a change in the electric field intensity between the lower surface of the second antenna 220 and the quartz window 230, which will disrupt the circumferential uniform electric field distribution in the reaction chamber, thereby causing the plasma morphology to shift and the uniformity of thin film deposition to decrease.

[0063] Optionally, the bottom through-slot 221 within the second antenna 220 and the transmission sleeve 310 can be clearance-fitted. The second gap between them has a preset size. This preset size can minimize the annular gap between the bottom through-slot 221 and the transmission sleeve 310, thereby suppressing microwave leakage and preventing air ionization within the gap. Furthermore, this preset size provides a reasonable compensation margin for the transmission sleeve 310 to avoid the risk of sliding, scraping, and jamming caused by thermal deformation. Similarly, the top through-slot 110 within the waveguide 100 and the transmission sleeve 310 can also be clearance-fitted, and the size configuration of the third gap between them is the same as the second gap described above, and will not be repeated here.

[0064] Alternatively, microwaves may leak outward from the third gap between the top through-slot 110 and the transmission sleeve 310 within the waveguide 100. To address this, a sealing groove can be machined around the top through-slot 110 and a gasket can be added to fill or block the annular gap between the two, thereby preventing microwave leakage from the top through-slot 110.

[0065] In the above embodiments, the second gap between the bottom through groove 221 and the transmission sleeve 310 and / or the third gap between the top through groove 110 and the transmission sleeve 310 are uniform with the annular gap around the transmission sleeve 310, thereby preventing electric field concentration arcing caused by a narrow gap on one side.

[0066] Furthermore, in some embodiments, the tuning device 300 may also include a microwave parameter measuring instrument and a controller. Figure 1 (Not shown). A microwave parameter measuring instrument is used to acquire microwave reflection parameters at the input port of the resonant cavity 200 and send them to the controller. Based on the received microwave reflection parameters at the input port of the resonant cavity 200, the controller can be configured to execute the resonant impedance tuning method provided in another aspect of the present invention.

[0067] Please combine Figure 3 A shared understanding. Figure 3 A flowchart of a method for tuning a resonant impedance according to some embodiments of the present invention is shown.

[0068] like Figure 3 As shown, in some embodiments of the present invention, the resonant impedance tuning method includes steps S310 to S340. Step S310: Obtain the microwave reflection parameters at the input port of the resonant cavity. Step S320: Determine whether the microwave reflection parameters are within the target range. Step S320: In response to the microwave reflection parameters being outside the target range, adjust the axial position of the tuning element to adjust the input port impedance of the resonant cavity. Step S330: In response to the microwave reflection parameters being within the target range, lock the position of the tuning element to complete the impedance adjustment.

[0069] For example, please combine Figure 4 A shared understanding. Figure 4 A flowchart of a method for tuning a resonant impedance according to other embodiments of the present invention is shown.

[0070] like Figure 4As shown, during step S310, a Vector Network Analyzer (VNA) can be used as the microwave parameter measuring instrument. The controller can be a Programmable Logic Controller (PLC). Specifically, step S311 can be executed, connecting the Vector Network Analyzer to the input port of the directional coupler to continuously acquire the microwave reflection parameters S11 within the cavity in real time, and transmitting them to the PLC via communication. The S-parameters, or reflection parameters, describe the signal reflection and transmission characteristics between microwave ports. S11 is the reflection parameter of the input port, representing how much power is reflected back to the signal source by the load (i.e., the resonant cavity + plasma) after the microwave is fed into the cavity from port 1 (i.e., the input port of waveguide 100 into resonant cavity 200). The more negative the value of the microwave reflection parameter S11, the smaller the reflected power, indicating better impedance matching.

[0071] During the execution of step S320, such as Figure 4 As shown, the specific executable step S321 is as follows: The PLC compares the received microwave reflection parameter S11 with a set threshold to determine whether it is within the target range. For example, the set threshold can be -30dB. When the microwave reflection parameter S11 is less than or equal to -30dB, this is the target range. Within this range, the microwave reflection power is only one-thousandth of the incident power, with almost no microwave reflection; the vast majority of the energy is fed into the cavity to excite the plasma, which is the system's preset optimal matching state.

[0072] If the microwave reflection parameter S11 is outside the target range, proceed to step S330 to adjust the axial position of the tuning element 320 to adjust the input port impedance of the resonant cavity 200. This input port is the output port of the VNA, and its impedance is typically 50Ω.

[0073] Furthermore, such as Figure 4 As shown, step S330 may further include steps S331 and S332.

[0074] The system determines whether the microwave reflection parameter S11 falls within a first threshold range or a second threshold range outside the target range, wherein the mismatch in the second threshold range is greater than that in the first threshold range. For example, the first threshold range can be between -30dB and -25dB (i.e., -30dB < S11 ≤ -25dB), and the second threshold range can be greater than -25dB (i.e., S11 > -25dB).

[0075] The first threshold range of -30dB to -25dB corresponds to a slight mismatch. When the microwave reflection parameter S11 is within this range, the reflected power ratio increases, and the matching deteriorates slightly, requiring fine-tuning. Therefore, if S11 is within the first threshold range, i.e., -30dB < S11 ≤ -25dB, step S331 can be executed to perform closed-loop fine-tuning of the axial position of the tuning element 320. Specifically, the PLC automatically starts the small-amplitude fine-tuning mode of the PID closed loop, driving the coupling loop synchronously and smoothly to perform small-amplitude rises and falls through the motor 330, in order to fine-tune the magnetic field coupling in the cavity. Through the PID adaptive closed-loop control logic, weak operating condition fluctuations can be accurately captured, and the tuning element 320 can be automatically driven to rise and fall to correct impedance drift.

[0076] The second threshold range, corresponding to a value greater than -25dB, falls within the severe mismatch range. When the microwave reflection parameter S11 is within this range, the reflected power is high, a large amount of microwaves bounce off the original path, resulting in low energy utilization and potential damage to the microwave source, requiring rapid coarse adjustment. Therefore, if S11 is within the second threshold range, i.e., S11 is worse than -25dB, step S332 can be executed to perform open-loop coarse adjustment of the axial position of the tuning element 320. Specifically, the PLC switches the adjustment mode to a fixed-step open-loop large-step coarse adjustment mode, driving the coupling loop with a fixed-step large-scale rise and fall to quickly reduce the reflected power, thereby improving the severe mismatch situation.

[0077] Continue as Figure 4 As shown, optionally, when the microwave reflection parameter S11 is within the target range, i.e., S11≤ -30dB, steps S341 and S342 can be further executed during the execution of step S340.

[0078] Step S341 determines whether motor 330 is running. If motor 330 is running, the motor 330 brake remains closed, thereby locking the position of the coupling loop and completing impedance adjustment. If motor 330 is not running, after starting motor 330, step S342 is executed so that after the microwave reflection parameter S11 falls back to the target range and stabilizes for 10 seconds (i.e., S11 remains less than or equal to -30dB for 10 seconds), the position of the coupling loop is locked, and impedance adjustment is completed.

[0079] In existing technologies, during the microwave output power ramp-up process, impedance matching is achieved by manually adjusting the position of the EH-Tuner or three-pin connector based on real-time feedback of the reflected power. However, this open-loop tuning method cannot quickly respond to fluctuations in operating conditions and struggles to maintain optimal cavity matching throughout the process, resulting in low microwave energy coupling efficiency and insufficient process stability. Therefore, in the aforementioned... Figure 3 and Figure 4In the embodiment shown, the PID adaptive closed-loop tuning system based on VNA real-time sampling can accurately capture weak operating condition fluctuations and automatically drive the tuning element 320 to rise and fall for correction. Combined with the high sensitivity adjustment characteristics of the tuning element 320, it can compensate for impedance drift caused by cavity operating condition fluctuations in real time, achieve adaptive and precise tuning, and maintain the matching state of ultra-low cavity reflection throughout the process.

[0080] Furthermore, combined Figure 5A and Figure 5B A shared understanding. Figure 5A A schematic diagram of the simulation results of the cavity structure without coupling ring in the prior art and its microwave reflection parameters is shown. Figure 5B A schematic diagram of simulation results of a cavity structure with a coupling ring and its microwave reflection parameters provided according to some embodiments of the present invention is shown.

[0081] like Figure 5A and Figure 5B As shown in the curve of microwave reflection parameter S11 on the right, the horizontal axis represents the microwave signal frequency (in MHz), and the vertical axis represents the S-parameter (dB). The resonant point of the cavity in this operation is approximately 909.49 MHz. Figure 5A As shown, without a tuning element 320 (e.g., a coupling ring) installed in the resonant cavity 200, the electric field is concentrated in the bottom reaction cavity region. The corresponding S11 curve shows that at the resonant frequency of 909.49 MHz, the S11 value is only -17.417 dB, which is in the severely mismatched range. Due to poor impedance matching, a large amount of microwave energy is reflected back to the waveguide, resulting in low effective power for exciting plasma within the reaction cavity 400.

[0082] And in Figure 5B In this design, by adding a coaxially welded tuning element 320 (e.g., a coupling ring) to the outer wall of the transmission sleeve 310, the overall electric field distribution within the cavity remains symmetrical, and the intrinsic field morphology of the cavity remains undistorted. The corresponding S11 curve shows an S11 value of -35.968 dB at the resonant frequency of 909.49 MHz. This S11 value is significantly lower than that without the coupling ring, resulting in a substantial reduction in reflected power. Excellent impedance matching between the cavity and the waveguide is achieved, allowing the vast majority of microwave energy to be fed downwards into the reaction cavity.

[0083] like Figure 5A and Figure 5B As shown, the transmission sleeve 310 drives the tuning element 320 to move axially up and down. By changing the axial position of the capacitive load in the cavity, the input impedance of the cavity is continuously adjusted. Under the premise of preserving the inherent resonance characteristics and plasma morphology of the cavity, the microwave reflection parameter S11 has the characteristics of wide adjustment range and high linearity. The cavity matching state can be precisely controlled in the optimal range, the tuning process is smooth and continuous, and the S11 parameter can be suppressed to -36dB.

[0084] Next, please refer to Figure 6 . Figure 6 A structural block diagram of a controller provided according to some embodiments of the present invention is shown.

[0085] like Figure 6 As shown, in some non-limiting embodiments, the controller 340 in the tuning device 300 includes a memory 341 and a processor 342. The memory 341 includes, but is not limited to, the computer-readable storage medium provided in the fourth aspect above, on which computer instructions are stored. The processor 342 is connected to the memory 341 and is configured to execute the computer instructions stored in the memory 341 to implement the resonant impedance tuning method as provided in the third aspect of the invention.

[0086] In the above embodiments provided by the present invention, a structureless perturbation fine-tuning is adopted, which does not require modification of the core resonant structure of the cavity throughout the process and does not damage the plasma distribution pattern. While achieving high-precision impedance matching, it ensures the constant state of the deposition process and significantly improves the uniformity of the thin film and the consistency of the process.

[0087] In summary, this invention provides a resonant impedance tuning device, a microwave plasma processing device, a resonant impedance tuning method, and a computer-readable storage medium. These technologies not only significantly reduce the risk of debris generation and micro-discharge in a vacuum environment, but also improve tuning accuracy and adjustment sensitivity without altering the core cavity structure or disrupting the plasma distribution pattern. This ensures the stability of the process state and significantly enhances the uniformity and consistency of thin film deposition.

[0088] Although the methods described above are illustrated and depicted as a series of actions for the sake of simplicity, it should be understood and appreciated that these methods are not limited by the order of the actions, as some actions may occur in a different order and / or concurrently with other actions from the illustrations and descriptions herein or not illustrated and described herein but which may be understood by those skilled in the art, according to one or more embodiments.

[0089] Those skilled in the art will further appreciate that the various illustrative logic blocks, modules, circuits, and algorithm steps described in conjunction with the embodiments disclosed herein can be implemented as electronic hardware, computer software, or a combination of both. To clearly illustrate this interchangeability between hardware and software, the various illustrative components, blocks, modules, circuits, and steps are described above in a generalized manner in terms of their functionality. Whether such functionality is implemented as hardware or software depends on the specific application and the design constraints imposed on the overall system. Those skilled in the art may implement the described functionality in different ways for each specific application, but such implementation decisions should not be construed as departing from the scope of the invention.

[0090] The various illustrative logic modules and circuits described in conjunction with the embodiments disclosed herein may be implemented or performed using a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. The general-purpose processor may be a microprocessor, but in alternatives, it may be any conventional processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors cooperating with a DSP core, or any other such configuration.

[0091] The steps of the methods or algorithms described in conjunction with the embodiments disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of both. The software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to a processor such that the processor can read and write information to / from the storage medium. In an alternative, the storage medium may be integrated into the processor. The processor and storage medium may reside in an ASIC. The ASIC may reside in a user terminal. In an alternative, the processor and storage medium may reside as discrete components in the user terminal.

[0092] In one or more exemplary embodiments, the described functionality may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software as a computer program product, the functionality may be stored or transmitted as one or more instructions or code on or through a computer-readable medium. A computer-readable medium includes both computer storage media and communication media, encompassing any medium that facilitates the transfer of a computer program from one location to another. A storage medium may be any available medium accessible to a computer. By way of example and not limitation, such a computer-readable medium may include RAM, ROM, EEPROM, CD-ROM or other optical disc storage, disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and is accessible to a computer. Any connection is also legitimately referred to as a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of a medium. As used in this article, disk and disc include compact discs (CDs), laser discs, optical discs, digital multi-purpose discs (DVDs), floppy disks, and Blu-ray discs. Disks typically reproduce data magnetically, while discs reproduce data optically using lasers. Combinations of these should also be included within the scope of computer-readable media.

[0093] The prior description of this disclosure is provided to enable any person skilled in the art to make or use this disclosure. Various modifications to this disclosure will be apparent to those skilled in the art, and the general principles defined herein may be applied to other variations without departing from the spirit or scope of this disclosure. Therefore, this disclosure is not intended to be limited to the examples and designs described herein, but should be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A resonant impedance tuning device, characterized in that, include: A transmission sleeve is fitted around the periphery of the first antenna, wherein the first antenna is axially inserted into the interior of the resonant cavity; A tuning element, coaxially sleeved around the periphery of the transmission sleeve, with its end face perpendicular to the first antenna; and A motor, located outside the resonant cavity, is connected to the first end of the transmission sleeve that extends out of the resonant cavity. It is used to drive the tuning element to move axially through the transmission sleeve, thereby adjusting the axial position of the capacitive load generated by the tuning element in the resonant cavity and adjusting the port input impedance of the resonant cavity.

2. The tuning device as described in claim 1, characterized in that, The transmission sleeve includes a sleeve structure made of metal, and the tuning element includes a coupling ring made of metal, the inner ring of which is coaxially fixed to the outer surface of the transmission sleeve, and the ring surface of the coupling ring is perpendicular to the first antenna.

3. The tuning device as described in claim 2, characterized in that, The inner ring of the coupling ring is fixed to the outer surface of the transmission sleeve by welding. After welding, the weld and the edges of the coupling ring are ground and polished to remove weld beads, burrs and sharp corners.

4. The tuning device as described in claim 1, characterized in that, The transmission sleeve and the first antenna are fitted with a clearance, and the first clearance between them is configured to allow the transmission sleeve to move axially without rubbing against the first antenna.

5. The tuning device as claimed in claim 1, characterized in that, The resonant cavity also includes: A quartz window is used to isolate the resonant cavity from the reaction chamber located below it; and The second antenna is located above the quartz window and below the first antenna. It forms an electromagnetic coupling with the first antenna to receive the microwave energy transmitted by the first antenna and radiate it to the reaction cavity below. The second antenna has a through slot in its center so that the transmission sleeve can move axially within the through slot.

6. The tuning device as described in claim 5, characterized in that, The second antenna is a loop antenna with a radial radius greater than that of the first antenna, so that the microwave radiation coverage of the second antenna is greater than that of the first antenna.

7. The tuning device as described in claim 5, characterized in that, The through groove and the transmission sleeve are fitted with a clearance, and the second gap between them has a preset size to allow for thermal deformation compensation of the transmission sleeve.

8. The tuning device as claimed in claim 1, characterized in that, Also includes: A microwave parameter measuring instrument is used to collect microwave reflection parameters at the input port of the resonant cavity; as well as The controller is configured to acquire microwave reflection parameters at the input port of the resonant cavity; Determine whether the microwave reflection parameters are within the target range; In response to the microwave reflection parameter being outside the target range, the axial position of the tuning element is adjusted to adjust the input port impedance of the resonant cavity; and in response to the microwave reflection parameter being within the target range, the position of the tuning element is locked to complete the impedance adjustment.

9. A microwave plasma processing device, characterized in that, include: A waveguide, positioned above the resonant cavity, is used to feed microwaves into the resonant cavity; The resonant cavity has a first antenna axially inserted inside it for conducting microwaves axially into the resonant cavity. The resonant impedance tuning device according to any one of claims 1 to 8 is used to adjust the input port impedance of the resonant cavity to match the characteristic impedance of the waveguide. as well as The reaction chamber, located below the resonant cavity, is used for microwave plasma process reactions.

10. A method for tuning resonant impedance, characterized in that, The tuning method, implemented via a tuning device for resonant impedance as described in any one of claims 1 to 8, comprises the following steps: Obtain the microwave reflection parameters at the input port of the resonant cavity; Determine whether the microwave reflection parameters are within the target range; In response to the microwave reflection parameters being outside the target range, the axial position of the tuning element is adjusted to adjust the input port impedance of the resonant cavity; and In response to the microwave reflection parameter being within the target range, the position of the tuning element is locked to complete the impedance adjustment.

11. The tuning method as described in claim 10, characterized in that, The step of adjusting the axial position of the tuning element to adjust the input port impedance of the resonant cavity in response to the microwave reflection parameter being outside the target range includes: In response to the microwave reflection parameter being outside the target range in a first threshold range, the axial position of the tuning element is fine-tuned in a closed loop; and In response to the microwave reflection parameter being in a second threshold range outside the target range, the axial position of the tuning element is coarsely adjusted in an open-loop manner, wherein the mismatch in the second threshold range is higher than that in the first threshold range.

12. A computer-readable storage medium storing computer instructions thereon, characterized in that, When the computer instructions are executed by the processor, the resonant impedance tuning method as described in claim 10 or 11 is implemented.

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