Plasma field uniformity adjustment device

Abstract

The application discloses a plasma field uniformity adjusting device, which comprises a cavity cover, a coil, a first adjusting part, an air nozzle and a second adjusting part. When processing small-size wafers or increasing the plasma concentration in the central area, the coil can be contracted in the centripetal direction to increase the central field strength, and the air nozzle can be close to the center of the working cavity to increase the central gas concentration. When processing large-size wafers or reducing the plasma concentration in the central area, the coil can be expanded in the centrifugal direction to reduce the central field strength, and the air nozzle can be away from the center of the working cavity to reduce the central gas concentration. By adjusting the radial position of the coil and the air nozzle, the distribution of the plasma can be improved. By the coordinated adjustment of the coil and the air nozzle, the dynamic matching between the plasma distribution and the reaction gas delivery can be realized, and the process uniformity and the equipment adaptability can be improved.

Description

Technical Field

[0001] This application relates to the field of wafer manufacturing equipment technology, and in particular to a plasma field uniformity adjustment device. Background Technology

[0002] In semiconductor manufacturing processes such as plasma-enhanced chemical vapor deposition (ICPCVD), the uniformity of the plasma field directly affects the deposition quality of thin films on the wafer surface. However, existing plasma processing equipment faces the following technical challenges when adapting to multi-size wafer processing:

[0003] Traditional equipment typically uses fixed horizontal spiral coils with fixed geometry and spatial position, resulting in a rigid distribution of the excited radio frequency magnetic field that cannot be dynamically adjusted according to wafer size. When processing wafers of different sizes, especially when switching from small to large wafers, the magnetic field strength at the coil edge region decreases significantly, and the plasma density difference between the wafer edge and center is large, which can easily lead to uneven thin film deposition rates and excessive film thickness deviations.

[0004] Meanwhile, existing equipment's reactive gas delivery systems mostly employ fixed-position nozzle designs, making it difficult to match the diffusion range of the reactive gas with the high-density plasma region. For large-size wafers, insufficient reactive gas concentration is prone to occur in the central region; while when processing small-size wafers, excessive gas diffusion in the edge regions can lead to material waste and process contamination, further exacerbating the imbalance in the coupling between plasma and reactive gas.

[0005] The aforementioned rigid coils and static air intake result in poor equipment adaptability to different wafer sizes. In actual production, it is necessary to frequently replace coil components or configure multiple sets of equipment adapted to different sizes, which not only increases costs but also makes it difficult to meet the needs of efficient and flexible semiconductor manufacturing. Summary of the Invention

[0006] The purpose of this application is to overcome the shortcomings of the prior art and provide a plasma field uniformity adjustment device.

[0007] This application provides a plasma field uniformity adjustment device, comprising: a cavity cover for sealing a working cavity, the working cavity for accommodating a wafer for plasma surface treatment; a coil, horizontally spirally extended and disposed on the front side of the cavity cover away from the working cavity, the coil being energized to excite a radio frequency field so as to generate plasma in the working cavity; a first adjustment member for driving the coil to rotate, the coil rotating in a centripetal direction, its spiral structure contracting to reduce the coverage area and increase the central field strength, the coil rotating in a centrifugal direction, its spiral structure expanding to increase the coverage area and decrease the central field strength; multiple gas nozzles, the multiple gas nozzles being equally spaced along the circumferential direction on the back side of the cavity cover facing the working cavity, for introducing reactive gas into the working cavity; and a second adjustment member for driving the gas nozzles closer to or further away from the center of the working cavity, thereby adjusting the concentration distribution of reactive gas in the working cavity.

[0008] Furthermore, the plasma field uniformity adjustment device also includes multiple sets of limiting mechanisms, each corresponding one-to-one with a coil loop. These limiting mechanisms constrain the coil's rotation path. Each limiting mechanism includes a fixed block and a movable block. The fixed block is located on the front of the cavity cover, while the movable block can move closer to or further away from the fixed block. The limiting mechanism has fixed and movable states. When the limiting mechanism is in the fixed state, the movable block is close to the fixed block, and the two can cooperate to clamp the coil, preventing it from moving. When the limiting mechanism is in the movable state, the movable block is away from the fixed block, allowing the coil to move. The front of the cavity cover also has multiple screw holes arranged radially and spaced along the coil. The fixed block has mounting holes that fit the screw holes. By selecting screw holes at different positions to install the fixed block, the spacing between adjacent coil loops can be adjusted, thereby changing the coil's contraction or expansion degree.

[0009] Furthermore, the coil is made of Litz wire, which is composed of multiple strands of mutually insulated metal wires twisted together. The diameter of the metal wires is no greater than the current skin depth of the coil at the operating frequency. The metal wires are covered with an insulating varnish film. The coil also includes a protective sleeve in which all the metal wires are constrained. The protective sleeve is used to provide mechanical protection. The end of the coil is a conductive joint that is welded together after the insulating varnish film of all the metal wires is removed. The conductive joint is used to connect to an external power source.

[0010] Alternatively, the coil is composed of multiple rigid conductor segments connected in series by a flexible conductive hinge, and the rotation of the coil is achieved by bending the flexible conductive hinge; the rigid conductor segments are made of copper tubes; the flexible conductive hinge is a flexible strip structure used to connect two adjacent rigid conductor segments and realize the electrical connection between the rigid conductor segments.

[0011] Furthermore, the plasma field uniformity adjustment device also includes a dynamic power supply module, which includes: a fixed power supply base located on the front of the cavity cover for connecting to an external power source; and a flexible conductive electrode plate that can elastically extend and retract, with one end of the flexible conductive electrode plate connected to the fixed power supply base and the other end connected to the coil; when the coil rotates centrifugally to diffuse, the flexible conductive electrode plate is stretched; when the coil rotates centripetally to contract, the flexible conductive electrode plate retracts.

[0012] Furthermore, the flexible conductive electrode plate has a strip-shaped structure comprising: a center signal line for transmitting radio frequency current and electrically connecting to a fixed power supply base and a coil; a first ground layer disposed on one side of the center signal line; a second ground layer disposed on the other side of the center signal line; and a flexible dielectric material layer disposed between the center signal line and the first ground layer, and between the center signal line and the second ground layer, the flexible dielectric material layer being made of polyimide or fluoropolymer; the center signal line, the first ground layer, the second ground layer, and the flexible dielectric material together constitute a radio frequency transmission line with controllable characteristic impedance; the characteristic impedance is 50Ω; the first ground layer and the second ground layer are interconnected at the ends of the flexible conductive electrode plate through conductive vias.

[0013] Furthermore, the cavity cover includes a connecting part and a dielectric window. The connecting part is used to connect to the working cavity. A through-hole radiating window is provided in the center of the connecting part. The dielectric window is used to seal the radiating window. The coil is placed on the dielectric window. The dielectric window is made of a high thermal conductivity insulating material. Cooling channels are integrated inside the dielectric window. The layout of the cooling channels corresponds to the projected area of ​​the coil. The cooling channels are used to introduce coolant for circulating heat dissipation. The surface of the dielectric window is coated with high-temperature resistant thermally conductive grease or has a flexible thermally conductive pad placed on it to fill microscopic gaps and reduce contact thermal resistance.

[0014] Furthermore, the second adjusting component includes: a rotary drive; a driving gear, located on the back of the cavity cover, the rotary drive being used to drive the driving gear to rotate; a driven gear, located on the back of the cavity cover, the driven gear being a ring-shaped bidirectional gear, with teeth on both its outer and inner ring surfaces, the outer ring teeth meshing with the driving gear; multiple linkage gears, the inner ring teeth of the driven gear meshing with the linkage gears; multiple linkage racks, the linkage racks, linkage gears, and air nozzles corresponding one-to-one, each linkage rack having an air nozzle, and each linkage rack meshing with a linkage gear; wherein, the linkage rack has a limiting oblique hole, a shoulder screw passing through the limiting oblique hole, the shoulder screw cooperating with the limiting oblique hole, which can limit the movement direction of the linkage rack, causing the linkage rack to translate obliquely at an acute angle to the radial direction of the working cavity, thereby driving the air nozzle to approach or move away from the center of the working cavity without changing the air outlet direction.

[0015] Furthermore, the plasma field uniformity adjustment device also includes: an annular gas supply pipe, located on the back of the cavity cover and surrounding all the gas nozzles; multiple sets of bellows, each bellows corresponding to a gas nozzle, with each gas nozzle connected to the annular gas supply pipe through a set of bellows; the annular gas supply pipe is connected to an external reactive gas supply device; through the annular gas supply pipe, the reactive gas supply device can simultaneously supply gas to all the gas nozzles; the bellows can also be stretched or compressed as the gas nozzles move to maintain a sealed connection between the gas nozzles and the annular gas supply pipe.

[0016] Furthermore, the driven gear includes: an I-shaped mounting bracket, arranged in a circular shape, sealed and fixed to the back of the cavity cover, with a mounting groove on each side of the I-shaped mounting bracket along the radial direction of the working cavity; an external gear, disposed in the mounting groove of the I-shaped mounting bracket facing the driving gear, the external gear meshing with the driving gear; an internal gear, disposed in the mounting groove of the I-shaped mounting bracket facing the air nozzle, the internal gear meshing with the linkage gear; a first magnet, disposed on the external gear; and a second magnet, disposed on the internal gear; the first magnet and the second magnet are opposite to each other and attract each other to realize non-contact transmission between the external gear and the internal gear.

[0017] Furthermore, Teflon pads are provided between the external gear, internal gear, and I-beam mounting bracket to reduce the frictional force experienced by the gears during rotation; and / or, the surfaces of the driving gear, driven gear, linkage gear, and linkage rack are coated with aluminum nitride, and the surface roughness of the aluminum nitride coating is not higher than 0.2 μm; and / or, the external gear is provided with multiple sets of first magnets, and the internal gear is provided with multiple sets of second magnets, both the first and second magnets are arranged in an alternating N and S pole configuration, the number of each is equal, and they are installed in a one-to-one correspondence using opposite poles attracting each other; and / or, the external... The gears and internal gears have slots on their opposing sides for mounting magnets, which are fixed with epoxy resin or non-magnetic metal baffles to prevent the magnets from coming out of the slots during rotation; and / or, the first and second magnets have yokes made of magnetically conductive material on their opposing sides, which can constrain the magnetic field and reduce magnetic line leakage; and / or, the air outlets are angled to the radial direction of the working chamber to introduce vortex airflow into the working chamber, and all air outlets have the same air outlet direction to work together to form a unidirectional vortex airflow in the working chamber.

[0018] This application provides a plasma field uniformity adjustment device, including a cavity cover, a coil, a first adjustment element, a gas nozzle, and a second adjustment element. The cavity cover seals the working cavity, ensuring the sealing of the wafer surface treatment environment. Using the first and second adjustment elements, when processing small-sized wafers or requiring an increase in the plasma concentration in the central region, the coil can rotate centripetally to shrink the coverage area and increase the central field strength, while the gas nozzle can move closer to the center of the working cavity to increase the central gas concentration. When processing large-sized wafers or requiring a decrease in the central region's plasma concentration, the coil can rotate centrifugally to diffuse the plasma, increasing the coverage area and decreasing the central field strength, while the gas nozzle can move away from the center of the working cavity to decrease the central gas concentration. By expanding or contracting the coil or changing the radial position of the gas nozzle, the plasma distribution can be specifically improved. Through the coordinated adjustment of the coil and the gas nozzle, dynamic matching between plasma distribution and reactive gas delivery can be achieved, contributing to improved process uniformity and equipment adaptability. Attached Figure Description

[0019] Figure 1 A schematic diagram of a plasma field uniformity adjustment device provided in this application;

[0020] Figure 2 for Figure 1 A top view of the structure of the plasma field uniformity adjustment device shown;

[0021] Figure 3 for Figure 1 The diagram shows a bottom view of the plasma field uniformity adjustment device.

[0022] Figure 4 for Figure 3 Enlarged view of the structure within the center circle;

[0023] Figure 5 for Figure 1 A cross-sectional view of the plasma field uniformity adjustment device shown.

[0024] Figure 6 for Figure 5 Enlarged view of the structure within the central circle. Detailed Implementation

[0025] 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.

[0026] This application provides a plasma field uniformity adjustment device, comprising: a cavity cover 10 for sealing a working cavity, the working cavity being used to accommodate a wafer for plasma surface treatment; a coil 21, horizontally spirally extended and disposed on the front side of the cavity cover 10 away from the working cavity, the coil 21 being energized to excite a radio frequency field so as to generate plasma in the working cavity; a first adjustment member 22 for driving the coil 21 to rotate, the coil 21 rotating in the centripetal direction, its spiral structure contracting, reducing the coverage area and increasing the central field strength, the coil 21 rotating in the centrifugal direction, its spiral structure expanding, increasing the coverage area and reducing the central field strength; a plurality of gas nozzles 31, the plurality of gas nozzles 31 being equally spaced along the circumferential direction on the back side of the cavity cover 10 facing the working cavity, for introducing reactive gas into the working cavity; and a second adjustment member 32 for driving the gas nozzles 31 closer to or further away from the center of the working cavity, thereby adjusting the concentration distribution of reactive gas in the working cavity.

[0027] It should be explained that the working chamber is the chamber for wafer surface treatment. The top of the working chamber is open for mounting the chamber cover 10, which seals the top of the working chamber. The working chamber and the chamber cover 10 cooperate to form a sealed reaction chamber. By configuring a vacuum pump set, the reaction chamber can be evacuated to a high vacuum state to prevent air and other impurities from affecting the surface treatment quality.

[0028] Furthermore, the cavity cover 10 is detachably connected to the working cavity (by screws or by a flip-top design). Opening the cavity cover 10 facilitates cleaning of the cavity or maintenance of components.

[0029] For details, please refer to Figure 1 In the illustrated embodiment, the cavity cover 10 includes a connecting part 11 and a dielectric window 12. The connecting part 11 is used to connect the working cavity. The center of the connecting part 11 is provided with a through-radiation window. The dielectric window 12 is used to seal the radiation window. The coil 21 is disposed on the dielectric window 12. The dielectric window 12 is made of a high thermal conductivity insulating material.

[0030] The connecting part 11 serves as the foundation for supporting and connecting the cavity cover 10. The connecting part 11 is roughly plate-shaped and made of stainless steel (such as 304L). This material possesses excellent mechanical strength, corrosion resistance (suitable for trace amounts of corrosive gases in plasma environments), and vacuum sealing properties, enabling it to withstand the vacuum negative pressure of the working chamber for extended periods without deformation. A circular radiation window is located at the center of the connecting part 11, extending squarely through its thickness. When the connecting part 11 is connected to the top of the working chamber, the radiation window faces the reaction chamber.

[0031] Combined with reference Figure 5The connecting part 11 has a dielectric window 12 on its front side. The dielectric window 12 is roughly disc-shaped, and its thickness is designed according to the requirements of radio frequency field penetration and mechanical strength. The dielectric window 12 covers the radiation window and can seal the radiation window (a sealing ring is provided between the two). The coil 21 is located on the side of the dielectric window 12 away from the working chamber. When the coil 21 is energized, the radio frequency magnetic field excited can penetrate the dielectric window 12, enter the reaction chamber, and ionize the reaction gas in the chamber to generate plasma. The dielectric window 12 has the characteristic of allowing radio frequency field penetration to ensure efficient transmission of radio frequency energy.

[0032] Combined with reference Figure 2 The coil 21 is a horizontally spiraling conductive coil (such as a copper spiral wire), which is laid out on the front side of the cavity cover 10. The spiral center of the coil 21 is coaxial with the center of the working cavity (which is also the wafer center). The number of spiral turns of the coil 21 can be designed according to process requirements. The spiral radius of the coil 21 covers the effective area at the top of the dielectric window 12 in order to accommodate the largest wafer size.

[0033] When in operation, after the coil 21 is connected to an external radio frequency power supply (such as 13.56MHz, 0-3000W), it will excite an alternating radio frequency magnetic field. The magnetic field can penetrate the dielectric window 12 and enter the reaction chamber, causing the reaction gas (such as silane, ammonia) in the chamber to ionize and generate high-density plasma.

[0034] Continue to refer to Figure 1 The coil 21 is connected to the first adjusting member 22 and can rotate around the spiral center under the drive of the first adjusting member 22. The first adjusting member 22 can be a manual adjusting member, such as a screw mechanism or a hand-adjusting screw; the first adjusting member 22 can also be an electric driving member, such as a rotary cylinder or a motor.

[0035] Figure 1 , Figure 2 In the embodiment shown, the first adjusting member 22 is a stepper motor, which is mounted above the cavity cover 10 via an X-shaped mounting bracket and directly opposite the center end of the coil 21. The motor shaft of the first adjusting member 22 is fixedly connected to the center end of the coil 21.

[0036] The first adjusting element 22 is used to provide rotational power to the coil 21, and the driving direction of the first adjusting element 22 is consistent with the helical direction of the coil 21. When the coil 21 rotates in the centripetal direction, its helical structure will contract, the coverage area will shrink, and the magnetic field strength at the center of the helix will increase (plasma gathers towards the center of the wafer); when the coil 21 rotates in the centrifugal direction, its helical structure will diffuse, the coverage area will expand, and the central magnetic field strength will decrease (plasma diffuses towards the edge of the wafer), thereby dynamically adjusting the distribution of plasma in the working cavity.

[0037] In practical use, the coil 21 can be adjusted according to the processing needs of wafers of different sizes (for example, coil 21 is contracted to focus plasma when the size is small, and coil 21 is expanded to cover a larger area when the size is large). The coil 21 can also be adjusted according to the test results (for example, when the test results show that the deposition rate in the middle is higher than the deposition rate at the edge, coil 21 is expanded to reduce the plasma concentration in the center, and when the test results show that the deposition rate in the middle is lower than the deposition rate at the edge, coil 21 is contracted to reduce the plasma concentration at the edge), thereby improving the plasma distribution in the reaction chamber and achieving better wafer processing results.

[0038] Combined with reference Figure 3 The nozzle 31 is a cylindrical nozzle. Its input end connects to an external reaction gas supply device, and its output end connects to the reaction chamber. Multiple nozzles 31 are evenly spaced along a circumferential direction on the back of the chamber cover 10. The outlets of all nozzles 31 face into the working chamber, and the axis of each nozzle 31 forms a preset angle with the radial direction of the working chamber to facilitate uniform gas diffusion. The nozzles 31 are connected to a second adjusting member 32 and can move towards or away from the center of the working chamber under the influence of the second adjusting member 32.

[0039] During operation, the reactive gas is injected into the reaction chamber through nozzle 31. The position of nozzle 31 determines the initial diffusion range of the gas within the reaction chamber. When nozzle 31 is close to the center of the working chamber, the gas is more likely to accumulate in the central region of the wafer; when nozzle 31 is far from the center of the working chamber, the gas is more likely to cover the edge region of the wafer. Therefore, by adjusting the position of nozzle 31, the concentration distribution of the reactive gas within the reaction chamber can be adjusted to match the plasma distribution.

[0040] The second adjusting component 32 can be a manually adjustable component, such as a dial composed of a gear-rack mechanism or a push structure composed of a push rod; the second adjusting component 32 can also be an electrically driven component, such as adding a rotary cylinder, a motor or other driving component to make the dial rotate automatically, or adding a cylinder, an electric cylinder or other driving component to make the push structure move radially automatically.

[0041] Multiple sets of second adjusting members 32 can be set so that each air nozzle 31 can change its radial position independently. Alternatively, with only one set of second adjusting members 32, all air nozzles 31 can change their radial positions synchronously through a linkage component.

[0042] In actual use, the coil 21 can be adjusted only, or the radial position of the nozzle 31 can be adjusted only, to improve the distribution of plasma in the reaction chamber. The coil 21 and the nozzle 31 can also be adjusted synchronously and correspondingly to enhance the improvement effect.

[0043] In one specific embodiment, the surface treatment equipment is used to process 12-inch (300mm) large-size wafers and 6-inch (150mm) small-size wafers.

[0044] Example 1: Adjustment process for 12-inch wafers.

[0045] Coil 21 is in a retracted state (covering a radius of 150mm, suitable for 6-inch wafers), and air nozzle 31 is in a position close to the center (65mm from the center of the working chamber).

[0046] The controller sends a "centrifugal diffusion" command to the first adjustment element 22, which drives the coil 21 to rotate clockwise. The spiral structure of the coil 21 gradually diffuses, eventually covering a radius of 300mm (matching the diameter of a 12-inch wafer). At this time, the radio frequency field excited by the coil 21 can uniformly cover the entire wafer area, thereby reducing the plasma density difference between the center and the edge.

[0047] Synchronously, the controller sends a "away from center" command to the second adjustment element 32, which drives all the gas nozzles 31 to move radially outward. Finally, the gas nozzles 31 are 140mm away from the center of the working chamber (ensuring that the gas diffuses from the edge of the wafer to the center and covers the entire wafer surface).

[0048] After the reaction chamber is evacuated, the gas nozzle 31 is used to introduce the reaction gas, and the coil 21 is energized to generate plasma. Since the coverage of the coil 21 matches the gas distribution of the gas nozzle 31, the thin film deposition rate on the 12-inch wafer surface is uniform, and the measured film thickness deviation between the wafer center and the edge is ≤3%, which meets the semiconductor process requirements.

[0049] Example 2: Adjustment process for 6-inch wafers.

[0050] Coil 21 is in a diffused state (covering a radius of 300mm, suitable for 12-inch wafers), and air nozzle 31 is located away from the center (140mm from the center of the working chamber).

[0051] The controller sends a "centripetal contraction" command to the first adjustment element 22, which drives the coil 21 to rotate counterclockwise. The spiral structure of the coil 21 gradually contracts, and the final coverage radius is reduced to 150mm (matching the diameter of a 6-inch wafer). At this time, the radio frequency field is focused on the central region of the working cavity, and the plasma density is highly uniform within the wafer region.

[0052] Synchronously, the controller sends a "near center" command to the second adjustment element 32, which drives all the gas nozzles 31 to move radially inward, so that the gas nozzles 31 are finally 65mm away from the center of the working chamber (to ensure that the gas is focused on the center area of ​​the wafer and avoid gas waste at the edges).

[0053] After the reaction chamber is evacuated, the gas nozzle 31 is introduced into the reaction gas, and the coil 21 is energized to generate plasma. Because the plasma focused by the coil 21 and the gas focused by the gas nozzle 31 are precisely matched, the film uniformity on the surface of the 6-inch wafer is excellent. The measured film thickness deviation between the center and the edge of the wafer is ≤2%, and the utilization rate of the reaction gas is improved compared with the traditional fixed gas nozzle design.

[0054] The plasma field uniformity adjustment provided in this application ensures the sealing of the wafer surface processing environment by sealing the working cavity with the cavity cover 10. Through the first adjustment element 22 and the second adjustment element 32, when processing small-sized wafers or requiring an increase in the plasma concentration in the central region, the coil 21 can rotate centripetally to shrink and reduce the coverage area, increasing the central field strength, while the gas nozzle 31 can move closer to the center of the working cavity to increase the central gas concentration. When processing large-sized wafers or requiring a decrease in the central region's plasma concentration, the coil 21 can rotate centrifugally to diffuse and increase the coverage area, reducing the central field strength, while the gas nozzle 31 can move away from the center of the working cavity to reduce the central gas concentration. By extending and retracting the coil or changing the radial position of the gas nozzle, the plasma distribution can be specifically improved. Through the coordinated adjustment of the coil and the gas nozzle, dynamic matching between plasma distribution and reactive gas delivery can be achieved, which helps improve process uniformity and equipment adaptability.

[0055] Optionally, the plasma field uniformity adjustment device provided in this application further includes multiple sets of limiting mechanisms 23, each of which corresponds to a ring of the coil 21. The limiting mechanism 23 is used to constrain the rotation path of the coil 21.

[0056] The coil 21 adjusts the plasma field distribution by rotating and retracting. During rotation, the coil 21 is prone to disordered twisting and coil displacement due to uneven force, which can lead to deformation of the spiral structure and deviation of the path from the preset trajectory, thus affecting the adjustment of the plasma field distribution. At the same time, if the coil 21 is not fixed after being adjusted to the target position, it is prone to displacement due to equipment vibration or airflow impact, which can affect the stability of the process.

[0057] The limiting mechanism 23 is set up so that the limiting mechanism 23 and the coil 21 correspond one-to-one. This can not only constrain the rotation path of the coil 21 and ensure that the coil 21 deforms in an orderly manner according to the preset path, but also fix the position of the coil 21 after it is adjusted to the correct position, thus ensuring the adjustment accuracy of the plasma field and the consistency of the process.

[0058] In one embodiment, the limiting mechanism 23 includes a guide groove and a clamping block. The guide groove is opened on the front of the cavity cover 10 and coincides with the preset rotation trajectory required for the rotation of the coil 21. The clamping block is detachably connected to the cavity cover 10 by bolts and can press the coil 21 into the guide groove.

[0059] In use, loosen the bolts of the clamping block before adjusting the coil 21 so that the coil 21 can rotate along the guide groove under the drive of the first adjusting component 22, and each ring can precisely contract or expand along the trajectory inside the groove; after the coil 21 reaches the target position, tighten the bolts again so that the clamping block presses against the coil 21 rings to prevent the coil 21 from shifting in subsequent processes.

[0060] In another embodiment, the limiting mechanism 23 includes a fixed block and a movable block. The fixed block is located on the front of the cavity cover 10, and the movable block can move closer to or further away from the fixed block. The limiting mechanism 23 includes a fixed state and a movable state. When the limiting mechanism 23 is in the fixed state, the movable block is close to the fixed block, and the two can cooperate to clamp the coil 21, so that the coil 21 cannot move. When the limiting mechanism 23 is in the movable state, the movable block is away from the fixed block, so that the coil 21 can move.

[0061] In one embodiment, a permanent magnet is embedded inside the fixed block, and the movable block is made of a magnetically attractive material. When there is no need to adjust the coil 21, the movable block abuts against the fixed block under the magnetic force of the permanent magnet, and the two cooperate to clamp the coil 21, keeping the limiting mechanism 23 in a fixed state. When the coil 21 needs to rotate, the magnetic force of the magnet is overcome, the movable block is pulled out, the fixing is released, and the limiting mechanism 23 is switched to the movable state.

[0062] In another embodiment, the front of the cavity cover 10 is provided with a clamp, a gripper, and other fixing components. By fixing the movable block to the fixed block with the fixing components, the limiting mechanism 23 can be kept in a fixed state. When the fixing components are released, the movable block can be moved easily so that the limiting mechanism 23 can switch to an active state.

[0063] In another embodiment, the fixed block and the movable block are locked by screws. When the screws are loosened, the movable block moves away from the fixed block, and the limiting mechanism 23 switches to the movable state. When the screws are tightened, the movable block presses against the fixed block, and the limiting mechanism 23 switches to the fixed state.

[0064] When setting up the screw-locking fixed block and movable block, it is not necessary to completely remove the screw or the movable block. Simply loosen the fixed block and the movable block, and the coil 21 will lose its clamping force and be able to rotate. At this time, a spring is added between the fixed block and the movable block. After the screw is loosened, the spring rebounds, which can open the fixed block and the movable block, making it easier for the coil 21 to rotate. After the coil 21 is adjusted into place, simply tighten the screw in the opposite direction. There is no need to find the removed movable block or screw, making the operation more convenient.

[0065] This application does not limit the specific configuration of the limiting mechanism 23, as long as it can constrain the deformation path of the coil 21 and fix the coil 21 after adjustment.

[0066] In one specific embodiment, a spring is provided between the fixed block and the movable block, and the fixed block and the movable block form a press-and-bounce type engagement structure; when the movable block is pressed, the spring expands, the movable block moves away from the fixed block, and the limiting mechanism 23 switches to the movable state; when the movable block is pressed again, the spring is compressed, the movable block presses against the fixed block again, and the limiting mechanism 23 switches to the fixed state.

[0067] In one embodiment, the state switching of the limiting mechanism 23 is achieved by a worker manually pressing the movable block.

[0068] In another embodiment, the limiting mechanism 23 further includes a linkage pressing component, which includes a pressing drive and multiple pressing blocks. Each pressing block corresponds to a movable block, and the pressing drive is used to drive the pressing block to press down on the corresponding movable block. When the coil 21 needs to be adjusted, the pressing drive causes all the pressing blocks to move, switching the limiting mechanism 23 to the active state so that the first adjusting member 22 can drive the coil 21 to contract centripetally or spread centrifugally. After the coil 21 is adjusted to the target position, the pressing drive causes all the pressing blocks to move again, switching the limiting mechanism 23 to the fixed state. The pressing drive and the first adjusting member 22 work together to achieve fully automatic processing of the rotation of the coil 21.

[0069] The pressing drive can be any drive structure, such as a pneumatic cylinder or an electric cylinder, capable of driving the pressing block closer to or away from the movable block. Multiple pressing drives can be set so that each pressing block can move independently; alternatively, only one pressing drive can be set, with all the pressing blocks arranged on a plate, so that all the pressing blocks can move synchronously when the pressing drive drives the plate to move.

[0070] Optionally, the front of the cavity cover 10 is also provided with a plurality of screw holes 13 arranged radially at intervals along the coil 21; the fixing block is provided with mounting holes adapted to the screw holes 13; by selecting screw holes 13 at different positions to install the fixing block, the interval between adjacent coils of the coil 21 can be adjusted, thereby changing the degree of contraction or expansion of the coil 21.

[0071] For details, please refer to Figure 2 In the illustrated embodiment, the front of the cavity cover 10 is provided with a row of screw holes 13, and multiple screw holes 13 are evenly distributed along the vertical direction (that is, the radial direction of the coil 21). All screw holes 13 have the same hole diameter and thread specification, and are fully compatible with the mounting holes on the fixing block (which can be ordinary through holes or threaded holes). The fixing block can be stably installed on any screw hole 13.

[0072] In use, adjust the position of the fixing block according to the required shrinkage / diffusion limit range of coil 21. To expand the diffusion of coil 21, install the fixing block in the screw hole 13 further away from the center in each radial region. In this case, the constraint position of the fixing block on the coil 21 loops moves outward, allowing coil 21 to expand to a larger radius when rotating centrifugally. To reduce the shrinkage of coil 21, install the fixing block in the screw hole 13 closer to the center in each radial region. The constraint position of the fixing block on the coil 21 loops moves inward, allowing coil 21 to shrink to a smaller radius when rotating centripetally.

[0073] The position of the fixing block can be flexibly adjusted by the radially spaced screw holes 13, thereby changing the scaling range of the coil 21, so that the degree of contraction / expansion of the coil 21 can adapt to more diverse needs.

[0074] When the linkage pressing assembly is provided and can cooperate with the first adjusting component 22 of the electric drive to realize the fully automatic adjustment of the coil 21, in order to facilitate the alignment of the pressing block with the fixed block with a variable position, the linkage pressing assembly also includes a pressing bracket. The pressing bracket extends radially along the coil 22 and has multiple screw holes, which correspond one-to-one with the screw holes on the cavity cover 10. The pressing block has mounting holes for installation on the pressing bracket. When adjusting the position of the fixed block on the cavity cover 10, the position of the pressing block on the pressing bracket is adjusted accordingly, so that the pressing block always corresponds one-to-one with the movable block.

[0075] To ensure reliable and repeatable deformation characteristics of coil 21, in one embodiment, coil 21 is made of Litz wire, which is composed of multiple strands of mutually insulated metal wires twisted together. The diameter of the metal wires is no greater than the current skin depth of coil 21 at its operating frequency, and the metal wires are covered with an insulating varnish film. Coil 21 also includes a protective sleeve in which all the metal wires are confined. The protective sleeve provides mechanical protection to prevent the metal wires from being scratched. The protective sleeve can also constrain the deformation path of coil 21 to a certain extent, making it rotate more regularly in a centripetal or centrifugal manner rather than twisting randomly, thereby improving the repeatability and lifespan of coil 21 deformation. The end of coil 21 is a conductive connector welded together after removing the insulating varnish film from all the metal wires. The conductive connector is used to connect to an external power source.

[0076] It's important to explain that Litzwire is a special conductive wire designed specifically for high-frequency alternating current applications. It consists of multiple strands of insulated fine metal wires twisted together, rather than a traditional single solid wire or monofilament. Its design aims to address the skin effect problem under high-frequency currents while maintaining flexibility and mechanical reliability.

[0077] High-frequency alternating current (such as 13.56MHz) exhibits "skin-tight" flow in conductors (current concentrates on the conductor surface, resulting in low internal current density). Litz wire breaks the conductor into multiple thin strands, each with a diameter no greater than the skin depth. This allows the current to be evenly distributed across the entire cross-sectional area of ​​each strand, effectively utilizing the conductor volume, significantly reducing high-frequency resistance, and minimizing the heat generated by coil 21 during operation. This prevents overheating from affecting plasma stability or damaging coil 21. Furthermore, the twisting of multiple thin metal wires exponentially increases overall flexibility, allowing coil 21 to withstand frequent rotational deformations (such as dozens of daily production adjustments). After deformation, it quickly recovers its original structure, preventing coil 21 failure due to wire breakage. Because the wire is composed of multiple twisted metal wires, even if a few wires break due to long-term fatigue or mechanical friction, the remaining wires can still conduct electricity normally, preventing overall power loss or a significant decrease in conductivity in coil 21. This contributes to improving the lifespan and process stability of coil 21.

[0078] Specifically, oxygen-free copper wire or silver-plated copper wire is selected. Oxygen-free copper wire has high conductivity, which can ensure low-loss transmission of radio frequency current; silver-plated copper wire has a thin layer of silver (usually 0.5-2μm thick) plated on the surface of oxygen-free copper, which can further reduce high-frequency resistance and improve oxidation resistance, avoiding oxidation of the wire surface and affecting conductivity during long-term use.

[0079] In one specific embodiment, the operating frequency of coil 21 is 13.56MHz. At this frequency, the skin depth of copper is δ≈17.8μm. Therefore, the theoretically optimal single wire diameter is d≤2δ=35.6μm. At this time, the cross-section of the metal wire can be fully utilized by the current (the current is mainly distributed within the surface depth δ. When the diameter is ≤2δ, the entire cross-section is almost within the effective conduction range, and there is no "ineffective area that the current cannot reach").

[0080] In engineering practice, to balance mechanical strength (avoiding breakage due to excessive thinness), manufacturing cost, and machinability, the actual diameter of the metal wire used is 50μm-100μm.

[0081] The core problem of the skin effect is that current concentrates on the surface, resulting in a small effective conductive area and high resistance in the wire. In traditional single-wire conductors (e.g., 1mm in diameter), the ineffective region (the interior where current cannot reach) accounts for an extremely high percentage (over 90%), leading to very high resistance. When the wire diameter is 50-100μm, although it is greater than 2δ (35.6μm), the proportion of the ineffective region is significantly reduced. Taking a 100μm diameter as an example, the cross-sectional area of ​​the effective conductive region (surface δ=17.8μm) is approximately 35% of the total cross-sectional area; with a 50μm diameter, the effective region accounts for over 60%. Compared to traditional wires, the resistance is greatly reduced, and the skin effect can be significantly suppressed.

[0082] In addition, Litz wire is made of many strands of fine wires twisted together. Even if the diameter of a single wire is slightly larger, the parallel strands can still disperse the current path and further offset the effect of the skin effect, making the total effective conductive area much larger than that of a single thick wire of the same cross-sectional area.

[0083] More specifically, each metal wire is coated with a polyurethane or polyimide insulating film. The polyurethane insulating film has good flexibility and temperature resistance, making it suitable for frequent deformation scenarios of coil 21; the polyimide insulating film (such as Kapton material) has better temperature resistance, can withstand the heat generated by the high-frequency current when coil 21 is working, and has high insulation resistance, which can completely isolate adjacent metal wires, avoid short circuits between strands after twisting, ensure that each metal wire conducts independently, and maximize the utilization of conductor cross-sectional area.

[0084] Multiple strands of insulated metal wires are wound into a bundle according to a regular twisting process (the number of strands is not fixed and needs to be designed according to the conductivity and flexibility requirements of coil 21, usually tens to hundreds of strands). The twisting direction is adapted to the helical direction of coil 21 to prevent the metal wire bundle from loosening when the coil rotates and deforms.

[0085] To address the issues of insufficient mechanical strength, susceptibility to scratches, and disordered deformation of the metal wire bundles, a protective sleeve is installed on the outside of the Litz wire, confining all the metal wires within the protective sleeve.

[0086] The protective sleeve is typically made of fluororubber or polytetrafluoroethylene (PTFE). Fluororubber sleeves offer high elasticity (they can stretch / compress with the coil 21), temperature resistance, and corrosion resistance (they can withstand trace amounts of corrosive gases in a plasma environment). They can directly wrap the metal wire bundle, preventing the coil 21 from scratching the metal wire and insulating varnish when it rubs against the limiting mechanism 23 and the cavity cover 10. PTFE sleeves have higher mechanical strength and better wear resistance, making them suitable for scenarios with more stringent protection requirements.

[0087] During rotational adjustment, coil 21 will slightly rub against the limiting mechanism 23 or the surface of cavity cover 10. The protective sleeve can directly withstand the external frictional force, preventing the internal metal wires and insulating varnish from being scratched or worn, and further preventing the metal wires from breaking due to mechanical damage. If there is no wire bundle constraint, the metal wire bundle may experience local twisting or misalignment, resulting in uneven deformation of the spiral structure of coil 21, which in turn leads to uneven distribution of the plasma field. The protective sleeve can limit the deformation direction of the wire bundle to a certain extent, ensuring that coil 21 contracts / diversifies radially in a regular manner when rotating, improving the repeatability of deformation and ensuring the accuracy of plasma field adjustment.

[0088] In another embodiment, the coil 21 is composed of multiple rigid conductor segments connected in series by a flexible conductive hinge, and the rotation of the coil 21 is achieved by bending the flexible conductive hinge; the rigid conductor segments are made of copper tubes and have coolant flowing inside; the flexible conductive hinge is a flexible strip structure used to connect two adjacent rigid conductor segments and realize the electrical connection between the rigid conductor segments.

[0089] The rigid conductor section is made of copper tubing. The inner and outer diameters of the copper tubing are designed according to the conductivity requirements (such as radio frequency current carrying capacity) and heat dissipation requirements (coolant flow rate) of coil 21. For example, a copper tubing with an outer diameter of 5mm and an inner diameter of 2mm, such as pure copper or oxygen-free copper, is selected as the rigid conductor section. Pure copper / oxygen-free copper has high conductivity and can transmit radio frequency current with low loss to meet the energy requirements of plasma excitation. The hollow structure of the copper tubing is used to introduce coolant (such as deionized water or ethylene glycol solution) to solve the problem of conductor heating under high frequency current.

[0090] Specifically, the high conductivity of the copper tube can carry out the function of radio frequency current transmission. After multiple rigid conductor segments are arranged according to a preset spiral trajectory, they can form the horizontal spiral profile of the coil 21, ensuring the overall shape of the coil 21 is stable and avoiding the deviation of the spiral radius due to its own deformation. Through the internal coolant circulation, the heat generated during operation (high frequency resistance heating, plasma radiation heat) can also be quickly discharged to maintain the temperature stability of the coil 21 and avoid high temperature affecting the radio frequency field distribution or damaging surrounding components (such as dielectric window 12).

[0091] A flexible conductive hinge is a bridge connecting two rigid conductor segments. It can be flexibly bent while maintaining conductivity.

[0092] In one embodiment, the flexible conductive hinge is a strip-shaped hinge, which is a composite structure consisting of a flexible strip substrate and an embedded conductive strip. The substrate is made of a high-temperature resistant insulating material (such as polyimide film or silicone rubber) with a thickness of 0.1-0.3 mm, possessing excellent flexibility and temperature resistance, and can adapt to frequent deformation scenarios of coil 21; the embedded conductive strip is oxygen-free copper foil or silver-plated copper foil (thickness 0.05-0.1 mm), and its two ends are fixed to the copper tube ends of adjacent rigid conductor segments by welding or bolting.

[0093] In this structure, the insulating substrate serves to constrain the direction of deformation, ensuring that the hinge can bend in the direction required for the rotation of coil 21, while the conductive strip serves to transmit radio frequency current.

[0094] In another embodiment, the flexible conductive hinge is a metal stranded wire hinge, employing short, extremely fine metal strands (similar to the stranded structure of Litz wire), specifically composed of multiple strands (e.g., 50-100 strands) of oxygen-free copper wire or silver-plated copper wire with a diameter of 0.05-0.1mm, and a length of 5-10mm (only sufficient to meet bending requirements, avoiding excessive length that could lead to disordered deformation). Both ends of the metal strand are welded to the copper tube ends of adjacent rigid conductor segments. This structure relies on the inherent flexibility of the metal strand to achieve bending, while the multi-strand strand design enhances fatigue resistance, preventing single-strand breakage that could lead to electrical connection failure.

[0095] Specifically, following the horizontal spiral trajectory of coil 21, multiple rigid conductor segments are arranged sequentially. Adjacent rigid conductor segments are connected by flexible conductive hinges, ultimately forming a continuous spiral coil structure of "rigid segment-hinge-rigid segment" connected in series. When the first adjusting element 22 drives coil 21 to contract centripetally or expand centrifugally, the core deformation only occurs at the flexible conductive hinge. The rigid conductor segments themselves maintain their shape and adjust their angle only as the hinge bends. Throughout the process, the flexible conductive hinge maintains the electrical connection between adjacent rigid conductor segments, ensuring that the radio frequency current can be continuously transmitted along the "rigid segment-hinge-rigid segment" path without the risk of current interruption.

[0096] Litz coils rely on their own bending deformation, which makes them prone to breakage due to material fatigue after long-term use. By adopting a "rigid section-hinge-rigid section" structure, the rigid conductor section does not need to bend. All deformation is borne by a specially designed flexible conductive hinge, and the coil 21 can be extended and retracted with only a small bending. This can significantly reduce material fatigue loss and extend the service life of the coil 21.

[0097] Optionally, the plasma field uniformity adjustment device provided in this application further includes a dynamic power supply module, which includes: a fixed power supply base located on the front of the cavity cover 10 for connecting to an external power source; and a flexible conductive electrode plate capable of elastic expansion and contraction, with one end connected to the fixed power supply base and the other end connected to the coil 21. The flexible conductive electrode plate is a pre-pressed zigzag or spiral metal foil strip or flexible circuit board with elastic deformation and recovery characteristics. When the coil 21 rotates and diffuses centrifugally, the flexible conductive electrode plate is stretched; when the coil 21 rotates and contracts centripetally, the flexible conductive electrode plate retracts.

[0098] The dynamic power supply module is a power connection component specifically designed for the dynamic characteristics of the coil 21's rotatable contraction / expansion. It can achieve stable and low-loss radio frequency current transmission between the external power supply and the coil 21 without restricting the deformation of the coil 21, avoiding the problem of traditional fixed power supply lines being pulled, broken, or tangled due to coil deformation.

[0099] Specifically, the fixed power supply socket is mounted on the edge area of ​​the front of the cavity cover 10 via an insulating bracket (away from the rotation range of the coil 21 to avoid hindering the deformation of the coil 21). The terminals of the fixed power supply socket are connected to an external RF power supply via a cable. The position of the fixed power supply socket remains unchanged, providing a stable fixed end for the power supply link.

[0100] One end of the flexible conductive electrode plate is connected to the conductive end of the fixed power supply base, and the other end is connected to the conductive connector of coil 21 (such as the welded connector of Litz wire or the copper tube end of the rigid conductor section). The flexible conductive electrode plate is initially zigzag or spiral in shape to ensure sufficient expansion and contraction allowance.

[0101] Flexible conductive electrode plates can be made of metal foil strips or flexible circuit boards (such as polyimide substrate + copper foil), and have excellent fatigue resistance.

[0102] When the first adjusting element 22 drives the coil 21 to rotate and contract inward, the coil 21 causes the free end of the flexible conductive electrode plate to move outward, and the zigzag / spiral structure is gradually stretched. The length of the flexible conductive electrode plate increases with the increase of the radius of the coil 21.

[0103] When the first adjusting element 22 drives the coil 21 to rotate and diffuse centrifugally, the flexible conductive electrode plate retracts under its own elastic restoring force, and the zigzag / spiral structure is refolded to avoid disordered accumulation or entanglement of the flexible conductive electrode plate due to length redundancy, ensuring that the coil 21 retraction path is not obstructed.

[0104] Throughout the adjustment process, the external power supply maintains an electrical connection with the coil 21 through the fixed power supply base and flexible conductive electrodes, and can be used without reconnecting the power.

[0105] Optionally, the flexible conductive electrode plate is a stripline structure comprising: a center signal line for transmitting radio frequency current and electrically connected to the fixed power supply base and coil 21; a first ground layer disposed on one side of the center signal line; a second ground layer disposed on the other side of the center signal line; and a flexible dielectric material layer disposed between the center signal line and the first ground layer, and between the center signal line and the second ground layer, the flexible dielectric material layer being made of polyimide or fluoropolymer; the center signal line, the first ground layer, the second ground layer, and the flexible dielectric material together constitute a radio frequency transmission line with controllable characteristic impedance.

[0106] Specifically, the flexible conductive electrode plate is flat and strip-shaped, with a thickness controlled between 0.3-1mm. The length is designed according to the maximum expansion and contraction range of coil 21 (with sufficient margin to accommodate the largest size of centripetal contraction / centrifugal diffusion). It can be pre-pressed into a zigzag or spiral shape to meet dynamic expansion and contraction requirements.

[0107] The flexible conductive electrode plate uses flexible substrates for each layer, with a minimum bending radius of 5mm. It can stretch or retract synchronously with the rotation and deformation of coil 21, and the structure of each layer does not peel or break during the stretching and contraction process, always maintaining the complete transmission line shape, which meets the core requirement of dynamic power supply module to deform with coil 21 and transmit power stably.

[0108] The center signal line is the core carrier of radio frequency energy transmission. It is made of oxygen-free copper foil or silver-plated copper foil with a thickness of 0.05-0.1mm (silver plating can further reduce high-frequency resistance). Its width is designed according to the characteristic impedance requirements (usually 1-3mm).

[0109] The function of the center signal line is to transmit radio frequency current. One end of the center signal line is connected to the conductive end of the fixed power supply base by welding or bolting to receive energy output from the external radio frequency power supply; the other end is fixedly electrically connected to the conductive connector of coil 21 to transfer radio frequency current to coil 21, providing the energy basis for plasma excitation.

[0110] The first and second grounding layers are symmetrically distributed on both sides of the center signal line (e.g., the first grounding layer is on top and the second grounding layer is on the bottom). The material of the grounding layers is the same as that of the center signal line, and the thickness is slightly thinner (0.03-0.05mm). The coverage area matches the width of the center signal line (or is slightly wider by 0.1-0.2mm to ensure shielding integrity).

[0111] The grounding layer serves two purposes: first, it provides a stable return path for the radio frequency current (high-frequency radio frequency current needs to form a closed loop). When the center signal line transmits forward current, the two grounding layers can transmit reverse return current, avoiding transmission loss caused by irregular return paths; second, it constructs a Faraday cage shielding structure. The two grounding layers, together with the center signal line and dielectric material layer in the middle, form a closed electromagnetic shielding space, which can completely confine the electric and magnetic fields generated by the radio frequency current between the layers. On the one hand, it isolates external electromagnetic interference (such as electromagnetic signals from components around the cavity cover 10), and on the other hand, it prevents internal radio frequency energy from radiating outward.

[0112] The flexible dielectric material layer has two layers, sandwiched between the center signal line and the first ground layer, and between the center signal line and the second ground layer, respectively. The thickness of the flexible dielectric material layer is controlled between 0.1-0.3mm according to the characteristic impedance requirements, and the material is polyimide or fluoropolymer (such as PTFE).

[0113] The flexible dielectric material layer serves two purposes: first, it provides insulation to prevent the center signal line from directly contacting the ground layer and causing a short circuit; second, the insulation resistance of the dielectric material layer is ≥10 Ω. 14The characteristic impedance is determined by two factors: first, the dielectric constant of the stripline structure is Ω·cm, which ensures reliable interlayer insulation; second, it determines the characteristic impedance. The characteristic impedance of the stripline structure is directly related to the dielectric constant and thickness of the dielectric material layer and the width of the center signal line. By selecting materials with specific dielectric constants (such as polyimide Dk≈3.5 and fluoropolymer Dk≈2.1) and precisely controlling the thickness, the characteristic impedance can be precisely controlled.

[0114] The multi-layer composite structure of the flexible conductive electrode plate is designed for high-frequency radio frequency (RF) applications at 13.56MHz and the need for dynamic expansion and contraction. Single-layer conductors are susceptible to electromagnetic interference and suffer significant energy radiation loss at high frequencies. In contrast, the multi-layer stripline structure, with its grounding layer shielding and dielectric material layer insulation, significantly improves RF energy transmission efficiency, ensuring that coil 21 receives sufficient energy to excite plasma. Furthermore, the multi-layer structure provides a "sandwich" reinforcement, making it more resistant to mechanical friction and environmental corrosion compared to single-layer conductors, thus extending the service life of the flexible conductive electrode plate and reducing maintenance costs.

[0115] It's important to clarify that characteristic impedance is a core electrical parameter of high-frequency radio frequency (RF) transmission lines. It is not DC resistance (which is independent of the resistivity of the conductor material), but rather the ratio of the voltage amplitude to the current amplitude at any point in a lossless RF signal propagating along the transmission line. Its magnitude is determined solely by the geometry of the transmission line (such as the width of the center signal line and the thickness of the flexible dielectric layer) and the dielectric constant of the dielectric material, and is independent of the length of the transmission line.

[0116] At an operating frequency of 13.56MHz, the characteristic impedance of flexible conductive plates is typically designed to be 50Ω, which is a common impedance standard for semiconductor devices such as RF power supplies and coils.

[0117] If the characteristic impedance is uncontrollable, it is easy to encounter a mismatch with the output impedance of the RF power supply or the input impedance of coil 21. In this case, some RF energy cannot be transmitted to coil 21 and will be reflected back to the power supply, resulting in a decrease in plasma excitation efficiency.

[0118] This allows for controllable characteristic impedance (ensuring it remains stable at 50Ω), achieving impedance matching between the power supply, flexible conductive electrode plate, and coil 21, keeping energy reflectivity below 2%, thereby maximizing plasma excitation efficiency. Controllable characteristic impedance also eliminates standing waves, ensuring uniform voltage / current distribution on the transmission line and avoiding the risks of arcing and overheating. Furthermore, controllable characteristic impedance blocks reflected wave generation, ensuring stable RF power supply output and enabling coil 21 to continuously excite a uniform RF field, thus guaranteeing plasma field uniformity and process consistency.

[0119] Optionally, the first grounding layer and the second grounding layer are connected to each other at the ends of the flexible conductive electrode plate through conductive vias.

[0120] The ends of the flexible conductive electrode plate refer to its two physical endpoints, i.e., the two ends that connect to external components. One end is the power supply connection end, used for electrical connection with the fixed power supply base; the other end is the load connection end, used for electrical connection with coil 21. These two ends are the input / output interfaces for radio frequency current. It is necessary to ensure the structural integrity of the grounding layer at this point to avoid shielding failure due to an unsealed end structure.

[0121] Conductive vias are metallized hole structures that penetrate the multi-layer structure of flexible conductive electrode plates. Specifically, a tiny circular hole (usually 0.2-0.5 mm in diameter) is made at the end of the flexible conductive electrode plate (power supply connection end, load connection end) in a direction perpendicular to the surface of the conductive electrode plate. The inner wall of the circular hole is covered with a layer of conductive metal (such as copper or silver) through electroplating or chemical deposition processes to form a conductive channel. This conductive channel can be in direct contact with the upper and lower grounding layers (first grounding layer and second grounding layer) at the same time, realizing the electrical connection between the two grounding layers.

[0122] Through the conductive vias, the first and second ground layers, which were originally independently distributed on both sides of the center signal line, are electrically connected at the ends of the flexible conductive electrode plate. That is, the current of the first ground layer can flow to the second ground layer through the conductive vias, and the current of the second ground layer can also flow back to the first ground layer. The two ground layers are no longer completely independent structures, but form a closed grounding loop at the ends.

[0123] The core function of the flexible conductive electrode plate is to transmit high-frequency radio frequency current, which requires the formation of a Faraday cage structure to confine electromagnetic energy between layers. If the two grounding layers are not connected at the ends, it will result in an open port at the ends, where radio frequency energy can easily radiate outwards, causing energy loss. At the same time, external electromagnetic signals (such as interference signals from components around the cavity cover 10) may also intrude from the port, affecting the stability of the radio frequency current.

[0124] By connecting two grounding layers at the end through conductive vias, the Faraday cage can be closed at the end, completely blocking the energy leakage path, while isolating external interference and ensuring the quality of radio frequency transmission.

[0125] Furthermore, the high-frequency radio frequency current relies on the ground plane to form a reverse return loop. If the two ground planes are independent at the ends, the return current can only flow along a single ground plane, which can easily lead to increased high-frequency resistance at the ends due to concentrated current density, causing transmission loss. However, the conductive via allows the two ground planes to be connected at the ends, enabling the return current to be freely distributed between the two ground planes (selecting a low-resistance path according to the current distribution pattern). This effectively reduces the current density at the ends, reduces high-frequency resistance, avoids localized heating due to excessive resistance, and ensures that radio frequency energy can be efficiently transmitted to coil 21, guaranteeing the plasma excitation efficiency.

[0126] Optionally, the cavity cover 10 includes a connecting part 11 and a dielectric window 12. The connecting part 11 is used to connect the working cavity. The center of the connecting part 11 is provided with a through-radiation window. The dielectric window 12 is used to seal the radiation window. The coil 21 is disposed on the dielectric window 12. The dielectric window 12 is made of a high thermal conductivity insulating material.

[0127] The dielectric window 12 needs to isolate the coil 21 (current-carrying conductor) from the working cavity (metal cavity). If the dielectric window 12 is not insulated, it will cause a short circuit between the coil 21 and the working cavity, which will not only interrupt the radio frequency current transmission, but may also damage the radio frequency power supply. Therefore, the material of the dielectric window 12 must have high insulation.

[0128] In addition, the heat generated when the coil 21 is working will be conducted to the dielectric window 12. If the dielectric window 12 has poor thermal conductivity, the heat will accumulate on the surface, eventually causing the dielectric window 12 to be too hot. On the one hand, it may cause the dielectric window 12 material to age and crack. On the other hand, high temperature will change the transmission characteristics of the radio frequency field, causing plasma density fluctuations. Therefore, the material of the dielectric window 12 also needs to have high thermal conductivity.

[0129] High thermal conductivity insulating materials have a stable dielectric constant (typically 8-10) and low absorption loss in 13.56MHz radio frequency fields, ensuring efficient penetration of radio frequency fields and avoiding energy waste caused by material absorption.

[0130] In one embodiment, the dielectric window 12 is made of aluminum nitride ceramic (AlN), which has a thermal conductivity of 180-220 W / (m·K) and an insulation resistance ≥10 Ω·m. 14 It has a strength of Ω·cm, a temperature resistance of ≥1000℃, and extremely low absorption loss in radio frequency fields. It also has excellent resistance to plasma corrosion and can withstand gases such as silane and ammonia in the ICPCVD environment for a long time.

[0131] In another embodiment, the dielectric window 12 is made of beryllium oxide ceramic (BeO), which has a thermal conductivity of 250-300 W / (m·K) and excellent insulation and temperature resistance, making it suitable for special scenarios with extremely high requirements for thermal conductivity.

[0132] In another embodiment, the dielectric window 12 is made of silicon carbide ceramic (SiC), with a thermal conductivity of approximately 120-150 W / (m·K) and good insulation properties (insulation resistance ≥10 Ω·K). 13 It has a strength of Ω・cm and high mechanical strength and wear resistance, making it suitable for scenarios where the medium window 12 needs to withstand greater pressure.

[0133] Optionally, a cooling channel is integrated within the medium window 12. The layout of the cooling channel corresponds to the projected area of ​​the coil 21. The cooling channel is used to introduce coolant for circulating heat dissipation.

[0134] Specifically, the cooling channels are internally integrated. During the sintering process of the dielectric window 12, a continuous channel structure is machined inside the dielectric window 12 through pre-embedded molds or subsequent precision drilling (laser drilling + mechanical milling). The channels are serpentine or grid-like in shape, and their layout strictly corresponds to the projection area of ​​the coil 21 on the dielectric window 12 (i.e., the area covered by the coil 21), ensuring that the channels can fully influence the area where the coil 21 is located and avoiding heat dissipation blind spots.

[0135] The diameter of the cooling channel is typically designed to be 2-3 mm (balancing coolant flow rate and the mechanical strength of the medium window 12, to avoid the medium window 12 from cracking due to excessively large channels). The inlet and outlet of the cooling channel are respectively located in the edge area of ​​the medium window 12 (away from the center of the working chamber to avoid interfering with the plasma), and both the inlet and outlet are machined with threaded interfaces for installing pressure-resistant hoses to connect to an external cooling circulator.

[0136] The coolant flowing through the cooling channels can be deionized water (resistivity ≥18MΩ・cm, to avoid the risk of short circuits caused by conductivity). During operation, the coolant is pumped into the cooling channels by a cooling circulator at a pressure of 0.3-0.5MPa and a flow rate of 5-8L / min. The coolant can fill the channels and flow rapidly to ensure efficient heat absorption.

[0137] The coolant circulation quickly removes the heat conducted from coil 21 to dielectric window 12, preventing localized overheating. Stable coil 21 temperature ensures stable conductivity and deformation characteristics, preventing helical structure misalignment or RF current loss due to temperature fluctuations.

[0138] Optionally, the surface of the dielectric window 12 is coated with high-temperature resistant thermal grease or has a flexible thermal pad placed therein to fill microscopic gaps and reduce contact thermal resistance.

[0139] Although coil 21 and dielectric window 12 are in direct contact, due to limitations in processing precision (e.g., the surface roughness of dielectric window 12 is typically Ra 0.8-1.6 μm, and the surface of coil 21 has microscopic protrusions due to wire stranding / rigid segment splicing), a large number of microscopic gaps invisible to the naked eye are formed at the contact surface. These gaps are filled with air, and the thermal conductivity of air is only 0.026 W / (m・K), far lower than that of aluminum nitride ceramic. This leads to a significant increase in contact thermal resistance. If left untreated, the heat generated by coil 21 is difficult to transfer to dielectric window 12 through thermal conduction, and even if coolant is introduced into the cooling channel, it cannot efficiently remove the heat from the coil.

[0140] High-temperature resistant thermal grease or flexible thermal pads can fill these microscopic gaps, replacing the low thermal conductivity air, and establishing a low thermal resistance heat transfer path from coil 21 to thermal medium, medium window 12, and cooling channel, ensuring that the heat from coil 21 can be efficiently transferred to the coolant.

[0141] In one embodiment, the second adjusting member 32 includes: a rotary drive member 32a; a driving gear 32b disposed on the back of the cavity cover 10, the rotary drive member 32a driving the driving gear 32b to rotate; a driven gear 32c disposed on the back of the cavity cover 10, the driven gear 32c being a ring-shaped bidirectional gear, with teeth on both its outer and inner ring surfaces, the outer ring teeth meshing with the driving gear 32b; multiple linkage gears 32d, the inner ring teeth of the driven gear 32c meshing with the linkage gears 32d; and multiple linkage racks 32e, the linkage racks 32e and the linkage gears... 32d and air nozzle 31 correspond one-to-one. Each linkage rack 32e is provided with an air nozzle 31, and each linkage rack 32e meshes with a linkage gear 32d. The linkage rack 32e is provided with a limiting waist-shaped hole, and a shoulder screw 32f passes through the limiting waist-shaped hole. The shoulder screw 32f cooperates with the limiting waist-shaped hole to restrict the movement direction of the linkage rack 32e, so that the linkage rack 32e moves obliquely at an acute angle to the radial direction of the working cavity, thereby driving the air nozzle 31 to move closer to or away from the center of the working cavity without changing the air outlet direction.

[0142] For details, please refer to Figures 3 to 6 In the illustrated embodiment, except for the rotary drive component 32a (which may be a rotary cylinder, motor, etc.), the rest of the second adjustment component 32 is integrated on the back side of the cavity cover 10 facing the working cavity.

[0143] Continue to refer to Figure 3 The driven gear 32c is arranged in a ring shape. The center of the driven gear 32c is coaxial with the center of the working cavity (which is also the center of coil 21 and the wafer center), and the whole gear surrounds the middle area of ​​the back of the cavity cover 10. The outer ring surface (outer circumference away from the center) and the inner ring surface (inner circumference facing the center) of the driven gear 32c are both machined with teeth, which is the core hub for power transmission.

[0144] Combined with reference Figure 5 The fixed end of the rotary drive 32a is fixed to the edge area of ​​the front of the cavity cover 10 (away from the coil 21 to avoid obstructing the rotation of the coil 21) by a bracket. The movable end passes through the cavity cover 10 and is connected to the drive gear 32b located on the back of the cavity cover 10. The drive gear 32b meshes with the outer ring teeth of the driven gear 32c to form a power input link.

[0145] Combined with reference Figure 3 and Figure 4 There are multiple linkage gears 32d, the same number as the air nozzle 31. The multiple linkage gears 32d are evenly distributed along the inner ring circumference of the driven gear 32c. Each linkage gear 32d meshes with the inner ring teeth of the driven gear 32c, so as to achieve the uniform distribution of power from the driven gear 32c to multiple directions.

[0146] Continue to refer to Figure 4The linkage rack 32e, linkage gear 32d, and air nozzle 31 are arranged in a one-to-one correspondence. Multiple linkage racks 32 are radially distributed inside the driven gear 32c. One end of each linkage rack 32e meshes with the corresponding linkage gear 32d, and the other end is fixedly mounted with an air nozzle 31. A limiting oblique hole (elongated through hole) is opened in the middle of the linkage rack 32e. A shoulder screw 32f is fixed at the corresponding position on the back of the cavity cover 10. The shank of the shoulder screw 32f passes through the limiting oblique hole. Two shoulder screws 32f are provided in the limiting oblique hole, and the two points restrict the line, so that the extension direction of the limiting oblique hole is at an angle to the radial direction of the working cavity. The movement direction of the linkage rack 32e is restricted by the shoulder screws 32f, and it can only move obliquely, and cannot rotate or deflect.

[0147] The second adjusting component 32, via a rack and pinion drive, enables synchronized position adjustment of multiple air nozzles 31. When the radial position of an air nozzle 31 needs adjustment, the rotary drive component 32a is activated, driving the driving gear 32b to rotate. The driving gear 32b, through outer ring teeth meshing, drives the driven gear 32c to rotate around the center of the working cavity. The inner ring teeth of the driven gear 32c synchronously drive all meshing linkage gears 32d to rotate. Because the driven gear 32c is annular and the linkage gears 32d are evenly spaced, all linkage gears 32d rotate in the same direction and at the same speed, thus achieving uniform power distribution. When the linkage gears 32d rotate, they drive the corresponding linkage rack 32e to move through tooth meshing. Since the linkage rack 32e is constrained by the limiting waist-shaped hole and the shoulder screw 32f, it can only translate obliquely at an acute angle to the radial direction of the working cavity.

[0148] For details, please refer to Figure 3 If the air nozzle 31 needs to be close to the center of the working chamber, the rotary drive 32a drives the drive gear 32b to rotate clockwise, the driven gear 32c to rotate clockwise, and the linkage gear 32d drives the rack to move inward along the oblique direction, and the air nozzle 31 moves closer to the center in sync. If the air nozzle 31 needs to be far away from the center of the working chamber, the rotary drive 32a drives the drive gear 32b to rotate counterclockwise, the driven gear 32c to rotate counterclockwise, and the linkage gear 32d drives the rack to move outward along the oblique direction, and the air nozzle 31 moves closer to the edge in sync.

[0149] Through the transmission and linkage structure of gear and rack, the synchronous adjustment of multiple gas nozzles 31 can be achieved, thereby ensuring the uniformity of gas distribution so that the gas forms a uniform diffusion area in the reaction chamber, and can more accurately match the plasma distribution after adjustment by coil 21.

[0150] Guided and limited by the waist-shaped hole and the shoulder screw 32f, the linkage rack 32e moves obliquely instead of rotating. When the gas nozzle 31 moves with the rack, it only changes its position and does not change the direction of the gas outlet. It always maintains a preset angle with the radial direction of the working cavity (which is also the radial direction of the wafer). In this way, the change in airflow state and concentration position caused by the deviation of the gas outlet direction of the gas nozzle 31 can be avoided, ensuring that the reactive gas always diffuses into the working cavity along a stable path, further improving the mixing uniformity of plasma and gas, and reducing the difference in film thickness between the wafer edge and the center.

[0151] Optionally, the plasma field uniformity adjustment device provided in this application further includes: an annular gas supply pipe 41, which is disposed on the back of the cavity cover 10 and surrounds all the gas nozzles 31; multiple sets of corrugated pipes 42, each corrugated pipe 42 corresponding to a gas nozzle 31, and any gas nozzle 31 is connected to the annular gas supply pipe 41 through a set of corrugated pipes 42; the annular gas supply pipe 41 is connected to an external reaction gas supply device; through the annular gas supply pipe 41, the reaction gas supply device can supply gas to all the gas nozzles 31 simultaneously; the corrugated pipes 42 can also be stretched or compressed as the gas nozzles 31 move to maintain a sealed connection between the gas nozzles 31 and the annular gas supply pipe.

[0152] For details, please refer to Figures 3 to 5 In the illustrated embodiment, both the annular gas supply pipe 41 and the corrugated pipe 42 are located on the back of the chamber cover 10. The annular gas supply pipe 41 is a ring-shaped pipe, coaxially arranged with the center of the working chamber, and surrounds the outside of all the gas nozzles 31 (the side away from the center of the working chamber). The annular gas supply pipe 41 can be fitted against the back of the chamber cover 10, or it can be suspended below the back of the chamber cover 10 by a bracket. The outer side of the annular gas supply pipe 41 is provided with a main gas pipe for connecting an external reaction gas supply device, and the inner side is provided with multiple small gas pipes for connecting the corrugated pipe 42.

[0153] Continue to refer to Figures 3 to 5 The bellows 42 consists of multiple sets, the same number as the air nozzles 31. One end of each set of bellows 42 is sealed to the air inlet of the corresponding air nozzle 31, and the other end is sealed to the small air tube of the annular air supply pipe 41. The bellows 42 is slightly compressed in its natural state, with sufficient stretching allowance to ensure that the connection will not break when the air nozzle 31 moves.

[0154] In use, the reaction gas supply equipment first delivers reaction gas to the annular gas supply pipe 41 through the main gas pipe. The reaction gas is then distributed through the annular gas supply pipe 41 to each group of corrugated pipes 42, and then delivered by the corrugated pipes 42 to the corresponding nozzles 31, and finally input into the working chamber through the nozzles 31. When the second adjusting component 32 drives the nozzle 31 to approach the center of the working chamber, the nozzle 31 causes the corrugated pipe 42 to stretch naturally, keeping the gas passage inside the pipe sealed. When the nozzle 31 moves away from the center of the working chamber, the corrugated pipe 42 moves and compresses synchronously with the nozzle 31, always maintaining the connection between the nozzle 31 and the annular gas supply pipe 41.

[0155] By supplying gas to all nozzles 31 simultaneously through the annular gas supply pipe 41, the gas pressure differences among the nozzles 31 caused by single-pipe gas supply can be avoided, ensuring a consistent initial concentration distribution of the reactant gas in the reaction chamber. The bellows 42, by moving and extending with the nozzles 31, avoids the fixed pipe restricting the displacement of the nozzles 31.

[0156] Optionally, the driven gear 32c includes: an I-shaped mounting bracket 32c1, which is arranged in a circular shape and sealed and fixed to the back of the cavity cover 10. Along the radial direction of the working cavity, a mounting groove is provided on each side of the I-shaped mounting bracket 32c1; an external gear 32c2, which is located in the mounting groove of the I-shaped mounting bracket 32c1 facing the driving gear 32b, and meshes with the driving gear 32b; an internal gear 32c3, which is located in the mounting groove of the I-shaped mounting bracket 32c1 facing the air nozzle 31, and meshes with the linkage gear 32d; a first magnet 32c4, which is located on the external gear 32c2; and a second magnet 32c5, which is located on the internal gear 32c3. The first magnet 32c4 and the second magnet 32c5 are opposite to each other and attract each other to realize non-contact transmission between the external gear 32c2 and the internal gear 32c3.

[0157] For details, please refer to Figure 6 In the illustrated embodiment, the I-shaped mounting bracket 32c1 is arranged in a circular shape, surrounding all the air nozzles 31. The I-shaped mounting bracket 32c1 is fixed to the back of the cavity cover 10 by bolts, and a sealing ring is provided between it and the cavity cover 10 to ensure the sealing of the connection. The cross-section of the I-shaped mounting bracket 32c1 is I-shaped. Along the radial direction of the working cavity (from the center to the edge), both sides of the I-shaped mounting bracket 32c1 (the outer side is the side facing the drive gear 32b, and the inner side is the side facing the air nozzle 31) are recessed to form two symmetrical T-shaped mounting grooves. The depth of the mounting grooves is adapted to the thickness of the outer gear 32c2 and the inner gear 32c3 so that the gears can be embedded and provide positioning and rotation space for the gears.

[0158] The I-shaped mounting bracket 32c1 provides a rotatable mounting bracket for the external gear 32c2 and the internal gear 32c3 without requiring modification of the cavity cover 10. Furthermore, after the cavity cover 10 seals the working cavity, the I-shaped mounting bracket 32c1 is sealed to the top surface of the working cavity (also with a sealing ring), which effectively avoids the problem of sealing leakage when the second adjusting member 32 performs internal transmission.

[0159] Continue to refer to Figure 6 The external gear 32c2 is also arranged in a circular shape, which fits the mounting groove on the outside of the I-shaped mounting bracket 32c1. After being inserted, it can rotate around the center of the working cavity. The outer teeth of the external gear 32c2 are exposed and mesh with the driving gear 32b. The inner end face of the external gear 32c2 is provided with at least one first magnet 32c4.

[0160] Continue to refer to Figure 6 The internal gear 32c3 is also arranged in a circular shape, with the internal and external gears arranged symmetrically. The internal gear 32c3 is adapted to the mounting groove on the inner side of the I-shaped mounting bracket 32c1, and can also rotate around the center of the working cavity after being inserted. The inner teeth of the internal gear 32c3 are exposed and mesh with the linkage gear 32d. At least one second magnet 32c5 is provided on the outer end face. The position of the second magnet 32c5 is opposite to that of the first magnet 32c4. The number of the two magnets is the same and they correspond one-to-one.

[0161] The first magnet 32c4 and the second magnet 32c5 are permanent magnets (such as neodymium iron boron magnets). The opposite magnetic poles of the first magnet 32c4 and the second magnet 32c5 are opposite to each other and attract each other, forming a non-contact magnetic transmission link. The driven gear 32c realizes power transmission through non-contact magnetic transmission.

[0162] Specifically, when the position of the air nozzle 31 needs to be adjusted, the rotary drive 32a is activated, driving the drive gear 32b to rotate. The drive gear 32b drives the external gear 32c2 to rotate in the outer groove of the I-shaped mounting bracket 32c1 through tooth meshing. When the external gear 32c1 rotates, the first magnet 32c4 on it rotates synchronously. Because the first magnet 32c4 and the second magnet 32c5 attract each other, the magnetic force drives the second magnet 32c5 and the internal gear 32c3 to rotate synchronously (the external gear 32c1 and the internal gear 32c3 have the same direction of rotation and the same speed, and there is no mechanical contact). When the internal gear 32c3 rotates, it drives the linkage gear 32d to rotate through the meshing of the inner teeth, thereby driving the linkage rack 32e to move obliquely and the air nozzle 31 closer to or away from the center of the working chamber.

[0163] The sealed mounting of the I-beam type mounting bracket 32c1 solves the problem of poor sealing in traditional integrated gear drives, thereby ensuring the purity of the plasma environment and preventing impurities from affecting the wafer process. The magnetic non-contact transmission solves the problem of easy wear in traditional integrated gear drives, which helps to extend the life of transmission components and reduce the frequency of equipment maintenance and operating costs.

[0164] Optionally, Teflon pads are provided between the external gear 32c2, the internal gear 32c3, and the I-shaped mounting bracket 32c1 to reduce the friction force experienced by the gears during rotation.

[0165] Specifically, the Teflon pad is installed at the contact gap between the external gear 32c2, the internal gear 32c3 and the I-shaped mounting bracket 32c1. When the gear rotates, it only contacts the pad and does not directly rub against the mounting bracket.

[0166] The Teflon material has an extremely low coefficient of friction, which can significantly reduce the frictional resistance between the external gear 32c2 and the internal gear 32c3 and the I-shaped mounting bracket 32c1 when they rotate, preventing the gears from jamming due to friction and causing transmission lag, thereby ensuring the adjustment accuracy of the air nozzle 31. At the same time, Teflon has strong temperature resistance, which can adapt to the temperature environment inside the working chamber. In addition, Teflon has good chemical stability and will not react with the gears or the mounting bracket, so it can maintain low friction characteristics for a long time and extend the overall service life of the driven gear 32c.

[0167] Optionally, the surfaces of the driving gear 32b, the driven gear 32c, the linkage gear 32d, and the linkage rack 32e are coated with an aluminum nitride coating, the surface roughness of which is not higher than 0.2 μm.

[0168] Specifically, the aluminum nitride coating can be applied to the surfaces of the driving gear 32b, the driven gear 32c (external gear 32c2, internal gear 32c3), the linkage gear 32d, and the linkage rack 32e using a magnetron sputtering process in physical vapor deposition (PVD).

[0169] The function of the aluminum nitride coating is to improve the corrosion resistance and wear resistance of components. Gears and racks are constantly in the vacuum environment behind the cavity cover 10, and may come into contact with trace amounts of corrosive gases (such as silane decomposition products) leaking from the working chamber. Aluminum nitride has excellent chemical stability, which can isolate corrosive media from contact with the substrate (such as steel or aluminum alloy), preventing components from rusting or oxidizing. At the same time, aluminum nitride has high hardness, which enhances the wear resistance of gear teeth and rack tooth surfaces, reducing wear during meshing and preventing increased transmission clearance due to wear, thus ensuring the adjustment accuracy of the air nozzle 31. Furthermore, aluminum nitride has a certain degree of insulation, which can prevent weak electric arcs generated between gears and racks due to metal-to-metal contact, avoiding interference with the stability of the radio frequency field.

[0170] Maintaining a surface roughness of ≤0.2μm ensures the meshing accuracy and transmission stability of the gear and rack. If the coating surface roughness is too high, microscopic protrusions and depressions will exist on the gear teeth and rack tooth surfaces, easily causing jamming or impact during meshing, leading to transmission lag (such as delayed adjustment response of the air nozzle 31), and even noise and additional wear. Low roughness allows for tighter contact between the meshing surfaces, reducing contact stress concentration, ensuring uniform power transmission, and avoiding positional errors of the air nozzle 31 due to transmission deviations. Simultaneously, a low-roughness surface is less prone to adhering to impurities (such as dust and coating debris), reducing interference from impurities on the meshing transmission and extending the maintenance cycle of components.

[0171] Optionally, the external gear 32c2 is provided with multiple sets of first magnets 32c4, and the internal gear 32c3 is provided with multiple sets of second magnets 32c5. The first magnets 32c4 and the second magnets 32c5 are arranged in an alternating N-pole and S-pole configuration, with equal numbers of each and correspondingly installed in a manner where opposite poles attract each other.

[0172] Specifically, multiple first magnets 32c4 are successively embedded on the inner surface of the external gear 32c2 in an alternating N-pole and S-pole sequence (using high-temperature resistant adhesive such as epoxy resin for fixation), forming a complete magnetic ring. Multiple second magnets 32c5 are successively embedded on the outer surface of the internal gear 32c3 in an alternating N-pole and S-pole sequence, with the number of pole pairs matching that of the magnetic ring of the first magnets 32c4. During installation, ensure that the centers of the internal gear magnetic ring and the external gear magnetic ring are aligned, and strictly ensure that the pole numbers correspond, that is, the N-pole magnet of the external gear magnetic ring faces the S-pole magnet of the internal gear magnetic ring, and the S-pole magnet of the external gear faces the N-pole magnet of the internal gear, ultimately forming a state of opposite pole attraction between the two sets of magnets.

[0173] The design of alternating N and S poles can form a continuous and uniform magnetic transmission link, avoiding torque fluctuations when a single pair of magnets is used for transmission. This ensures that the rotational speeds of the external gear 32c2 and the internal gear 32c3 are completely consistent and there is no transmission lag. Ultimately, this achieves precise translation of the linkage rack 32e and ensures the adjustment accuracy of the air nozzle 31.

[0174] Optionally, the external gear 32c2 and the internal gear 32c3 have slots for mounting magnets on their opposite sides, which are fixed with epoxy resin glue or non-magnetic metal baffles to prevent the magnets from coming out of the slots during rotation.

[0175] The slots are structures on the external gear 32c2 and internal gear 32c3 used to position the magnets, precisely positioning them. The dimensions of the slots are adapted to the shapes of the first magnet 32c4 and the second magnet 32c5, accurately fixing the magnets in their preset positions, preventing installation misalignment, and ensuring the stability of magnetic transmission. Simultaneously, the slots can also withstand the centrifugal force of the magnets during rotation; during gear rotation, the magnets tend to detach due to centrifugal force, and the sidewalls of the slots can prevent this displacement, providing mechanical support and initially preventing the magnets from falling off, laying the foundation for subsequent fixing (epoxy resin adhesive / baffles).

[0176] In one embodiment, the first magnet 32c4 and the second magnet 32c5 are first embedded into the corresponding gear slots, ensuring that the magnets are tightly attached to the bottom and sidewalls of the slots without any looseness. Then, a high-temperature resistant and high-strength epoxy resin adhesive (such as a two-component epoxy adhesive with a temperature resistance of ≥200℃) is evenly applied along the gap between the magnet and the slot (the adhesive layer thickness is controlled at 0.1-0.2mm to avoid the adhesive overflow affecting the rotation of the gear or the alignment of the magnet poles). After application, the gear is placed in a room temperature environment until the adhesive has cured according to the curing requirements (usually 24 hours), so that the magnet and the slot form a firm bond.

[0177] In another embodiment, the non-magnetic metal baffle is made of stainless steel (such as 304) or copper alloy, which can avoid magnetic interference with the magnet poles. According to the distribution range of the slots on the side of the gear, the non-magnetic metal baffle is processed into a ring or arc-shaped thin sheet (thickness 0.5-1mm). First, the magnet is embedded in the slot, and then the baffle is covered on the side of the gear with the slot. The baffle is fixed to the gear with non-magnetic screws (such as copper screws) (the screw holes avoid the slot positions to prevent damage to the magnet). The baffle completely covers the openings of all the slots, thus preventing the magnet from falling off.

[0178] Optionally, the first magnet 32c4 and the second magnet 32c5 are provided with magnetic yokes made of magnetically conductive material on their opposite sides. The magnetic yokes can constrain the magnetic field and reduce the leakage of magnetic lines of force.

[0179] It should be explained that the magnetic yoke is a magnetic field confinement component made of magnetically permeable materials (such as electrical pure iron or silicon steel sheets). It is roughly square-shaped and possesses excellent magnetic permeability (far exceeding that of air). Its core characteristic is its ability to guide the magnetic field lines generated by the magnets along a predetermined path, preventing them from diffusing into non-working areas. Essentially, it optimizes the magnetic field distribution through a low-resistivity path, ensuring that the magnetic force is concentrated on the opposing pole regions of the first magnet 32c4 and the second magnet 32c5, rather than leaking randomly.

[0180] Specifically, the gear is provided with a slot, and a magnetic yoke is provided between the slot and the magnet (that is, the outer side of the first magnet 32c4 facing away from the second magnet 32c5 and the inner side of the second magnet 32c5 facing away from the first magnet 32c4 are provided with a magnetic yoke). The magnetic yoke and the magnet are fixed by non-magnetic high-temperature resistant adhesive (such as epoxy glue) or non-magnetic screws (to avoid interfering with the magnetic field) to ensure that the magnetic yoke and the magnet are tightly fitted without gaps.

[0181] The first magnet 32c4 and the second magnet 32c5 transmit power through the attraction between opposite poles. Without a yoke, some magnetic field lines would leak to the side of the magnets away from each other (non-pole region), reducing the effective magnetic field strength in the pole region and resulting in insufficient transmission torque (potentially causing gear slippage). The yoke, with its excellent magnetic permeability, guides the leaked magnetic field lines back into the magnetic circuit, concentrating them between the poles of the first magnet 32c4 and the second magnet 32c5. This increases the magnetic field strength in the pole region, enhancing the attraction between them and ensuring stable power transmission, preventing transmission lag due to insufficient torque. Simultaneously, the yoke confines the magnetic field lines within a closed magnetic circuit formed by the yoke, magnet, pole magnet, and another yoke, preventing outward diffusion of the magnetic field, avoiding electromagnetic interference to surrounding components, and ensuring the operational stability of the entire plasma field uniformity adjustment device.

[0182] Optionally, the air outlet direction of the air nozzle 31 is set at an angle to the radial direction of the working chamber so as to introduce vortex airflow into the working chamber. All air nozzles 31 have the same air outlet direction and work together to form a unidirectional vortex airflow in the working chamber.

[0183] The radial direction of the working chamber refers to the straight line from the center of the working chamber to the chamber wall, while the air outlet direction of the nozzle 31 is neither directly towards the center nor directly away from the center, but forms a certain angle with the radial direction. See details for reference. Figure 3 In the illustrated embodiment, the air nozzle 31 does not point to the center of the circle, but points in a direction that deviates from the center.

[0184] If the gas nozzle 31 emits gas radially, all the gas nozzles 31 will point to the same point. The gas will easily be sprayed directly to that point, causing a sudden increase in the gas concentration in that area, which will affect the uniformity of the plasma reaction.

[0185] An angled gas outlet direction creates a vortex-like airflow from the outside in and from top to bottom (the gas first rotates and mixes along the cavity wall, then gradually and evenly diffuses downwards to the wafer surface). This vortex breaks the static distribution of the gas, allowing different reactive gases (such as silane and ammonia) to quickly and fully fuse, and ensuring that the gas composition and concentration are highly consistent at any location within the working cavity. This fundamentally avoids localized concentration anomalies, ensures consistent process conditions across all areas of the wafer, and prevents differences in wafer surface film thickness caused by uneven gas mixing.

[0186] The vortex airflow also increases the residence time of the gas in the plasma region, allowing the reacting gas more time to interact with the radio frequency field, thereby improving the ionization rate, generating more plasma, reducing the waste of unreacted gas being directly extracted, improving gas utilization, and reducing process costs.

[0187] The above embodiments merely illustrate 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 plasma field uniformity adjustment device, characterized in that, include: Cavity cover (10) for sealing the working cavity, which is used to accommodate a wafer for plasma surface treatment; The coil (21) is arranged in a horizontal spiral and is located on the front of the cavity cover (10) away from the working cavity. When the coil (21) is energized, it can generate a radio frequency field so that plasma is generated in the working cavity. The first adjusting element (22) is used to drive the coil (21) to rotate. When the coil (21) rotates in the centripetal direction, its spiral structure contracts, which can reduce the coverage area and increase the central field strength. When the coil (21) rotates in the centrifugal direction, its spiral structure expands, which can increase the coverage area and reduce the central field strength. Multiple air nozzles (31) are evenly distributed along the circumferential direction on the back of the cavity cover (10) facing the working chamber, for introducing reaction gas into the working chamber; The second adjusting member (32) is used to drive the gas nozzle (31) closer to or further away from the center of the working chamber, thereby adjusting the concentration distribution of the reactive gas in the working chamber.

2. The plasma field uniformity adjustment device according to claim 1, characterized in that, It also includes multiple sets of limiting mechanisms (23), each of which corresponds to a loop of the coil (21) and is used to constrain the rotation path of the coil (21). The limiting mechanism (23) includes a fixed block and a movable block. The fixed block is located on the front of the cavity cover (10), and the movable block can move closer to or further away from the fixed block. The limiting mechanism (23) includes a fixed state and an active state; When the limiting mechanism (23) is in the fixed state, the movable block is close to the fixed block, and the two can cooperate to clamp the coil (21), so that the coil (21) cannot move. When the limiting mechanism (23) is in the active state, the movable block moves away from the fixed block so that the coil (21) can move; The front of the cavity cover (10) is also provided with a plurality of screw holes (13) arranged radially at intervals along the coil (21). The fixing block is provided with mounting holes that are compatible with the screw holes (13); By selecting different positions of the screw holes (13) to install the fixing blocks, the spacing between adjacent coils of the coil (21) can be adjusted, thereby changing the degree of contraction or expansion of the coil (21).

3. The plasma field uniformity adjustment device according to claim 1, characterized in that, The coil (21) is made of Litz wire, which is made of multiple strands of mutually insulated metal wires twisted together. The diameter of the metal wires is not greater than the current skin depth of the coil (21) at the working frequency. The metal wires are covered with an insulating varnish film. The coil (21) also includes a protective sleeve in which all of the metal wires are constrained, and the protective sleeve is used to provide mechanical protection. The end of the coil (21) is a conductive connector formed by welding after removing the insulating varnish film from all the metal wires. The conductive connector is used to connect to an external power source. or, The coil (21) is composed of multiple rigid conductor segments connected in series by a flexible conductive hinge, and the rotation of the coil (21) is achieved by bending the flexible conductive hinge; The rigid conductor section is made of copper tubing; The flexible conductive hinge is a flexible strip structure used to connect two adjacent rigid conductor segments and to achieve electrical connection between the rigid conductor segments.

4. The plasma field uniformity adjustment device according to claim 1, characterized in that, It also includes a dynamic power supply module, which includes: A fixed power supply base is located on the front of the cavity cover (10) for connecting an external power source; A flexible conductive electrode plate, which is elastically expandable and contractible, with one end of the flexible conductive electrode plate connected to the fixed power supply base and the other end connected to the coil (21); When the coil (21) is centrifugally rotated and diffused, the flexible conductive electrode plate is stretched; When the coil (21) rotates and contracts in a centripetal manner, the flexible conductive electrode plate retracts.

5. The plasma field uniformity adjustment device according to claim 4, characterized in that, The flexible conductive electrode plate has a strip-shaped wire structure, including: The center signal line is used to transmit radio frequency current and is electrically connected to the fixed power supply base and the coil (21); The first grounding layer is located on one side of the center signal line; The second grounding layer is located on the other side of the center signal line; And a flexible dielectric material layer disposed between the center signal line and the first ground layer, and between the center signal line and the second ground layer, wherein the flexible dielectric material layer is made of polyimide or fluoropolymer; The center signal line, the first ground layer, the second ground layer, and the flexible dielectric material together constitute a radio frequency transmission line with controllable characteristic impedance. The characteristic impedance is 50Ω; The first grounding layer and the second grounding layer are connected to each other at the ends of the flexible conductive electrode plate through conductive through holes.

6. The plasma field uniformity adjustment device according to claim 1, characterized in that, The cavity cover (10) includes a connecting part (11) and a medium window (12). The connecting part (11) is used to connect the working cavity. The center of the connecting part (11) is provided with a through radiation window. The medium window (12) is used to seal the radiation window. The coil (21) is disposed on the medium window (12). The medium window (12) is made of a highly thermally conductive insulating material; The medium window (12) integrates a cooling channel, the layout of which corresponds to the projection area of ​​the coil (21), and the cooling channel is used to introduce coolant for circulating heat dissipation. The surface of the medium window (12) is coated with high-temperature resistant thermally conductive silicone grease or has a flexible thermally conductive pad placed therein to fill the microscopic gaps and reduce contact thermal resistance.

7. The plasma field uniformity adjustment device according to claim 1, characterized in that, The second adjusting member (32) includes: Rotary drive component (32a); A drive gear (32b) is located on the back of the cavity cover (10), and the rotary drive (32a) is used to drive the drive gear (32b) to rotate. A passive gear (32c) is located on the back of the cavity cover (10). The passive gear (32c) is a ring-shaped bidirectional gear with teeth on both its outer and inner ring surfaces. The outer ring teeth mesh with the active gear (32b). Multiple linkage gears (32d), wherein the inner ring teeth of the driven gear (32c) mesh with the linkage gears (32d); Multiple linkage racks (32e), the linkage racks (32e), the linkage gears (32d) and the air nozzles (31) correspond one-to-one, each linkage rack (32e) is provided with an air nozzle (31), and each linkage rack (32e) meshes with one linkage gear (32d); The linkage rack (32e) is provided with a limiting waist-shaped hole, and a shoulder screw (32f) is inserted in the limiting waist-shaped hole. The shoulder screw (32f) cooperates with the limiting waist-shaped hole to restrict the movement direction of the linkage rack (32e), so that the linkage rack (32e) moves obliquely at an acute angle to the radial direction of the working cavity, thereby driving the air nozzle (31) to move closer to or away from the center of the working cavity without changing the air outlet direction.

8. The plasma field uniformity adjustment device according to claim 7, characterized in that, Also includes: An annular air supply pipe (41) is provided on the back of the cavity cover (10) and surrounds all the air nozzles (31); Multiple sets of corrugated pipes (42), each corrugated pipe (42) corresponds to one of the air nozzles (31), and any one of the air nozzles (31) is connected to the annular air supply pipe (41) through a set of corrugated pipes (42); The annular gas supply pipe (41) is connected to an external reaction gas supply device; Through the annular gas supply pipe (41), the reaction gas supply device can simultaneously supply gas to all the gas nozzles (31); The bellows (42) can also be stretched or compressed as the air nozzle (31) moves to maintain a sealed connection between the air nozzle (31) and the annular air supply pipe.

9. The plasma field uniformity adjustment device according to claim 7, characterized in that, The driven gear (32c) includes: An I-shaped mounting bracket (32c1) is arranged in a circular shape and sealed and fixed to the back of the cavity cover (10). Along the radial direction of the working cavity, an mounting groove is provided on each side of the I-shaped mounting bracket (32c1). An external gear (32c2) is disposed in a mounting groove on the side of the I-shaped mounting bracket (32c1) facing the driving gear (32b), and the external gear (32c2) meshes with the driving gear (32b); An internal gear (32c3) is disposed in the mounting groove on the side of the I-shaped mounting bracket (32c1) facing the air nozzle (31), and the internal gear (32c3) meshes with the linkage gear (32d); The first magnet (32c4) is disposed on the external gear (32c2); The second magnet (32c5) is disposed on the internal gear (32c3); The first magnet (32c4) and the second magnet (32c5) are opposite to each other and attract each other to achieve non-contact transmission between the external gear (32c2) and the internal gear (32c3).

10. The plasma field uniformity adjustment device according to claim 9, characterized in that, Teflon pads are provided between the external gear (32c2), the internal gear (32c3), and the I-shaped mounting bracket (32c1) to reduce the friction force experienced by the gears during rotation. And / or, the surfaces of the driving gear (32b), the driven gear (32c), the linkage gear (32d), and the linkage rack (32e) are coated with an aluminum nitride coating, the surface roughness of which is not higher than 0.2 μm; And / or, the external gear (32c2) is provided with multiple sets of the first magnet (32c4), and the internal gear (32c3) is provided with multiple sets of the second magnet (32c5). The first magnet (32c4) and the second magnet (32c5) are arranged in an alternating N pole and S pole manner, and the number of the two is equal and they are installed in a one-to-one correspondence in the manner of opposite poles attracting each other. And / or, the external gear (32c2) and the internal gear (32c3) have slots for mounting magnets on their opposite sides, which are fixed with epoxy resin glue or non-magnetic metal baffles to prevent the magnets from coming out of the slots during rotation. And / or, the first magnet (32c4) and the second magnet (32c5) are provided with magnetic yokes made of magnetically conductive material on their opposite sides, the magnetic yokes being able to confine the magnetic field and reduce the leakage of magnetic lines of force; And / or, the air outlet direction of the air nozzle (31) is set at an angle to the radial direction of the working chamber so as to introduce vortex airflow into the working chamber. All the air nozzles (31) have the same air outlet direction and work together to form a unidirectional vortex airflow in the working chamber.

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