Plasma device

Abstract

This disclosure provides a plasma device, belonging to the field of semiconductor equipment technology. The plasma device includes: a dielectric cylinder; a first cover plate covering the upper part of the dielectric cylinder, forming a plasma generation space together with the dielectric cylinder; a coil disposed outside the dielectric cylinder; a housing located below the dielectric cylinder; a second cover plate connected to the lower part of the dielectric cylinder and covering the upper part of the housing, forming a workpiece processing space together with the housing; at least one acceleration module is disposed in the second cover plate; the acceleration module includes: an electrode, an insulating layer, and an electrode feeder, wherein the insulating layer covers the electrode, the electrode feeder is used to feed energy into the electrode to form an electric field, the electric field is used to adjust the horizontal velocity of ions in the plasma flowing from the plasma space to the workpiece processing space, thereby adjusting the horizontal velocity of free radicals in the plasma; a grid located below the acceleration module and above the workpiece processing space.

Description

Technical Field

[0001] This disclosure relates to the field of semiconductor equipment technology, and more particularly to a plasma device. Background Technology

[0002] Plasma equipment based on remote plasma technology is a crucial process tool in semiconductor chip manufacturing. Remote plasma technology generates plasma at a distance from the wafer. As the plasma passes through a grid, the grid eliminates most of the ions in the plasma, reducing ion bombardment of the wafer. The neutralized free radicals in the plasma continue to move and reach the wafer surface to undergo chemical reactions, completing the wafer surface treatment. However, plasma equipment in related technologies often exhibits poor uniformity in wafer surface treatment. Summary of the Invention

[0003] This disclosure provides a plasma device.

[0004] As one aspect of this disclosure, an embodiment provides a plasma device, comprising: a dielectric cylinder; a first cover plate covering the upper part of the dielectric cylinder, forming a plasma generation space together with the dielectric cylinder; a coil disposed on the outside of the dielectric cylinder for exciting process gas in the plasma generation space into plasma; a housing located below the dielectric cylinder; a second cover plate connected to the lower part of the dielectric cylinder and covering the upper part of the housing, forming a workpiece processing space together with the housing; at least one acceleration module is disposed in the second cover plate; wherein the acceleration module comprises: an electrode, an insulating layer, and an electrode feeder, wherein the insulating layer covers the electrode, the electrode feeder is used to feed energy into the electrode to form an electric field, the electric field is used to adjust the horizontal velocity of ions in the plasma flowing from the plasma space to the workpiece processing space, thereby adjusting the horizontal velocity of free radicals in the plasma; and a grid located below the acceleration module and above the workpiece processing space.

[0005] In some embodiments, there are multiple acceleration modules, and the multiple acceleration modules are spaced apart and evenly distributed along a preset circumference.

[0006] In some embodiments, the diameter of the preset circumference is larger than the diameter of the space in the workpiece processing space.

[0007] In some embodiments, the plasma device further includes a voltage control module electrically connected to the electrode feeders of the plurality of acceleration modules, respectively, to control the intensity of the electric field formed by the electrodes of the plurality of acceleration modules.

[0008] In some embodiments, the plurality of acceleration modules are symmetrically distributed about the longitudinal center plane of the plasma device.

[0009] In some embodiments, the plurality of acceleration modules are symmetrically distributed about the transverse center plane of the plasma device.

[0010] In some embodiments, the electrode is plate-shaped and parallel to the axial direction of the plasma device.

[0011] In some embodiments, the electrode feeder is connected to the upper part of the electrode; the electrode feeder is electrically connected to the voltage control module via a wire; the second cover plate is provided with a cable management groove, the groove opening of the cable management groove is located on the upper surface of the second cover plate, and the wire is received into the cable management groove.

[0012] In some embodiments, the second cover plate is provided with a mounting hole, the opening of which is located on the upper surface of the second cover plate, and the acceleration module is detachably installed in the mounting hole.

[0013] In some embodiments, the first cover plate is provided with a cooling gas channel, which is used to guide cooling gas through the first cover plate and to the outer wall of the medium cylinder.

[0014] In some embodiments, the air inlet of the cooling gas channel is located on the upper surface of the first cover plate and is positioned close to the central axis of the plasma device.

[0015] In some embodiments, the outlet of the cooling gas channel is located on the lower surface of the first cover plate and corresponds to the periphery of the medium cylinder; there are multiple outlets, and the multiple outlets are distributed at intervals along the circumference of the medium cylinder.

[0016] In some embodiments, the first cover plate is provided with a coolant channel that extends circumferentially along the first cover plate.

[0017] In some embodiments, the inlet and outlet of the coolant channel are located on the side of the first cover plate, and the inlet is spaced above the outlet.

[0018] This embodiment of the invention can precisely control the degree of ion acceleration by adjusting the voltage applied to the electrodes of the acceleration module, thereby flexibly adjusting the radial concentration distribution of free radicals on the wafer surface, which helps to improve the uniformity of wafer surface treatment and thus improves the uniformity of wafer surface treatment.

[0019] The above overview is for illustrative purposes only and is not intended to be limiting in any way. Further aspects, embodiments, and features of this disclosure will become readily apparent from the accompanying drawings and the following detailed description, in addition to the illustrative aspects, embodiments, and features described above. Attached Figure Description

[0020] In the accompanying drawings, unless otherwise specified, the same reference numerals throughout the various drawings denote the same or similar parts or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings depict only some embodiments disclosed in this disclosure and should not be construed as limiting the scope of this disclosure.

[0021] Figure 1 A schematic diagram of the structure of a plasma device according to an embodiment of the present disclosure is shown; Figure 2 A schematic diagram of the structure of the second cover plate according to an embodiment of the present disclosure is shown. Figure 1 ; Figure 3 A schematic diagram of the structure of an acceleration module according to an embodiment of the present disclosure is shown; Figure 4 A schematic diagram of the structure of the second cover plate according to an embodiment of the present disclosure is shown. Figure 2 ; Figure 5 A schematic diagram of the structure of a first cover plate according to an embodiment of the present disclosure is shown.

[0022] Explanation of reference numerals in the attached drawings: 10-First cover plate; 11-Cooling gas channel; 12-Coolant channel; 13-Process gas channel; 20-Dielectric cylinder; 21-Plasma generation space; 30-Coil; 40-Second cover plate; 41-Acceleration module; 411-Electrode; 412-Insulating layer; 413-Electrode feeder; 50-Box; 51-Workpiece processing space; 61-First sealing ring; 62-Second sealing ring; 63-Third sealing ring; 70-Grid. Detailed Implementation

[0023] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of this disclosure. Therefore, the drawings and description are to be considered exemplary in nature and not restrictive.

[0024] In related technologies, the path of free radicals in plasma from the plasma generation space vertically downward to the wafer surface in the workpiece processing space is relatively long. As the free radicals diffuse freely, they are prone to concentration differences in different areas when they reach the wafer surface, resulting in poor uniformity of wafer surface processing.

[0025] This embodiment provides a plasma device. By setting an acceleration module in the second cover plate located above the workpiece processing space, the electric field provided by the acceleration module can accelerate the ions in the plasma about to enter the grid to increase the horizontal velocity of the ions. By using ions to bombard free radicals, the horizontal velocity of the free radicals is increased, thereby adjusting the concentration distribution of free radicals on the wafer surface, thereby adjusting the uniformity of free radicals on the wafer surface and improving the uniformity of wafer surface processing.

[0026] The structure, function, and implementation process of the plasma device in this embodiment will be illustrated below with reference to the accompanying drawings.

[0027] Please refer to Figures 1 to 4 The plasma device provided in this embodiment includes: a dielectric cylinder 20; a first cover plate 10, which covers the upper part of the dielectric cylinder 20 and together with the dielectric cylinder 20 forms a plasma generation space 21; a coil 30, which is disposed on the outside of the dielectric cylinder 20 and is used to excite the process gas in the plasma generation space 21 into plasma; a housing 50, which is located below the dielectric cylinder 20; and a second cover plate 40, which is connected to the lower part of the dielectric cylinder 20 and covers the upper part of the housing 50, together with the housing 50 forming a workpiece processing space 51; the second cover plate 40 is provided with... At least one acceleration module 41 is provided; wherein the acceleration module 41 includes: an electrode 411, an insulating layer 412, and an electrode feeder 413, wherein the insulating layer 412 covers the electrode 411, and the electrode feeder 413 is used to feed energy into the electrode 411 to form an electric field, the electric field being used to adjust the horizontal velocity of ions in the plasma flowing from the plasma space to the workpiece processing space 51, thereby adjusting the horizontal velocity of free radicals in the plasma; a grid 70 is located below the acceleration module 41 and above the workpiece processing space 51. The workpiece 80 may include a wafer.

[0028] The dielectric tube 20 is typically cylindrical. The axis of the dielectric tube 20 is parallel to the axis of the plasma device. The dielectric tube 20 can be made of quartz; therefore, it can also be called a quartz tube.

[0029] The upper end of the dielectric cylinder 20 is sealed and covered by a first cover plate 10, together forming a relatively enclosed plasma generation space 21. A first sealing ring 61 is abutted between the first cover plate 10 and the dielectric cylinder 20. Exemplarily, the first cover plate 10 includes a first plate body, the lower surface of which is provided with a downwardly extending extension ring. The extension ring is located near the outer edge of the first plate body, and its inner sidewall gradually slopes outwards in a downward direction. When the first plate body covers the upper end of the dielectric cylinder 20, the extension ring is located on the outer side of the dielectric cylinder 20, and the first sealing ring 61 abuts between the inner sidewall of the extension ring and the outer sidewall of the dielectric cylinder 20.

[0030] A coil 30 is arranged around the outside of the dielectric cylinder 20. This coil 30 is connected to a radio frequency power supply. When process gas is introduced into the plasma generation space 21, radio frequency current is passed through the coil 30, generating an alternating electromagnetic field, thereby exciting the process gas to form a plasma containing a large number of ions, free radicals, and other particles. The specific composition of the process gas can be set according to actual needs; this embodiment does not impose any limitations.

[0031] The upper port of the housing 50 is connected and sealed to the lower part of the dielectric cylinder 20 via a second cover plate 40. The second cover plate 40 and the housing 50 together form a workpiece processing space 51. A support structure for carrying the wafer is disposed within the workpiece processing space 51. For example, the lower part of the dielectric cylinder 20 is inserted into the central hole of the second cover plate 40, and a second sealing ring 62 is abutting between the outer wall of the dielectric cylinder 20 and the wall of the central hole of the second cover plate 40. The second cover plate 40 covers the upper end of the housing 50, and a third sealing ring 63 is abutting between the lower surface of the second cover plate 40 and the upper surface of the housing 50.

[0032] At least one acceleration module 41 is embedded within the second cover plate 40. The acceleration module 41 includes an electrode 411, an insulating layer 412, and an electrode feeder 413. The electrode 411 can be a metal component, such as one made of conductive materials like aluminum or stainless steel. The insulating layer 412 can be made of insulating material and tightly covers the outer periphery of the electrode 411, completely isolating the electrode 411 from the surrounding second cover plate 40. The electrode feeder 413 can be a metal conductor connected to the electrode 411. This electrode feeder 413 is connected to an external power source to feed electrical energy into the electrode 411.

[0033] When a certain voltage (such as radio frequency voltage or DC voltage) is applied to electrode 411 through electrode feeder 413, an electric field is formed on the side of electrode 411 facing the central axis of the plasma device. This electric field is located in the path of the plasma flowing from the plasma generation space to the workpiece processing space 51. This electric field mainly acts on the ions in the plasma that diffuses downward from the upper plasma generation space 21 and is about to enter the workpiece processing space 51. The electric field force accelerates the ions, significantly increasing the horizontal velocity component of the ions (i.e., the velocity parallel to the wafer surface, simply referred to as horizontal velocity), thereby increasing the horizontal velocity of the free radicals colliding with the ions.

[0034] Below the second cover plate 40, and near the acceleration module 41, there is a grid 70. The grid 70 is densely covered with through holes to equalize the plasma flow and block most of the ions.

[0035] In this embodiment, an acceleration module 41 is provided in the second cover plate 40. The electric field generated by the acceleration module 41 horizontally accelerates the ions, giving them a greater horizontal velocity. As these accelerated ions move downwards, they collide with electrically neutral free radicals. Through momentum transfer, the free radicals are propelled by the ions, and their horizontal velocity is correspondingly increased. By adjusting the voltage (such as voltage amplitude, frequency, or waveform) applied to the electrode 411 of the acceleration module 41, the degree of ion acceleration can be precisely controlled, thereby flexibly adjusting the radial concentration distribution of free radicals on the wafer surface. Ultimately, the free radical flux (or concentration) received at various points on the wafer surface becomes more uniform, significantly improving the consistency of the wafer surface treatment effect and enhancing the uniformity of the wafer surface treatment.

[0036] In some embodiments, there are multiple acceleration modules 41, and the multiple acceleration modules 41 are spaced apart and evenly distributed along a preset circumference. For example, there may be 4, 6, 8, 10 or more acceleration modules 41, and the specific number of acceleration modules 41 can be set according to actual needs.

[0037] In this embodiment, by setting multiple uniformly distributed acceleration modules 41, a uniform or independently adjustable electric field ring can be formed in the circumferential direction of the wafer, ensuring that ions coming down from the plasma generation space 21 can be accelerated by the corresponding acceleration module 41 regardless of their radial orientation, thereby effectively improving the uniformity of the wafer surface treatment.

[0038] In some embodiments, the diameter of the preset circumference is larger than the diameter of the space in the workpiece processing space 51. In this way, the annular region where the multiple acceleration modules 41 are distributed covers and extends beyond the edge of the wafer surface.

[0039] In this embodiment, the acceleration module 41 is set on a circumference larger than the actual area of ​​the wafer. The electric field generated by the acceleration module 41 can accelerate ions that exceed the edge of the wafer (that is, ions corresponding to the periphery of the wafer). After these ions collide with free radicals, they can more effectively push the free radicals located directly above the wafer and corresponding to the periphery of the wafer further into the space above the wafer, thereby accurately compensating for the free radical concentration in the wafer edge region and significantly improving the uniformity of the wafer edge.

[0040] In some embodiments, to improve the flexibility and intelligence of process control, the plasma device further includes a voltage control module, which is electrically connected to the electrode feeders 413 of the plurality of acceleration modules 41 respectively, so as to control the intensity of the electric field formed by the electrodes 411 of the plurality of acceleration modules 41 respectively.

[0041] The voltage control module is electrically connected to the electrode feed 413 of each acceleration module 41 via independent lines. In this way, the voltage control module can independently control the voltage signal (including voltage amplitude, frequency, phase or on / off) applied to the electrode 411 of each acceleration module 41, thereby separately and precisely regulating the intensity of the electric field generated by each acceleration module 41, and realizing the adjustment of free radical concentration at a set position on the wafer surface.

[0042] In some application scenarios, the enclosure 50 can be equipped with a detection structure for detecting the concentration of free radicals or a detection structure for detecting the surface treatment effect of the wafer. The detection results of the detection structure are used to provide a reliable reference for the voltage control module to control the acceleration module 41.

[0043] In this embodiment, the intensity of the electric field in a certain area can be flexibly and specifically enhanced or weakened. For example, if real-time monitoring reveals that the etching rate on the right side of the wafer is too slow, the voltage of the acceleration module 41 located on the right side can be increased separately to increase the horizontal velocity of ions in that area, thereby pushing more free radicals to the right side of the wafer surface and achieving dynamic compensation.

[0044] In other embodiments, each acceleration module 41 may be configured with an independent voltage control module.

[0045] In some embodiments, the plurality of acceleration modules 41 are symmetrically distributed about the longitudinal center plane of the plasma device. The plurality of acceleration modules 41 are also symmetrically distributed about the transverse center plane of the plasma device.

[0046] In this configuration, the longitudinal, transverse, and vertical directions are all perpendicular to each other, with the vertical direction being the straight line. For example, see the diagram. Figure 4 As shown, Figure 4 The left and right directions are horizontal. Figure 4 The vertical direction is the vertical direction. Figure 4 The direction perpendicular to the paper is called the vertical direction.

[0047] In this embodiment, the acceleration modules 41 are symmetrically distributed to avoid the problem of etching or deposition on one side of the wafer being faster than the other.

[0048] In some embodiments, electrode 411 is plate-shaped and parallel to the axial direction of the plasma device. For example, electrode 411 is rectangular plate-shaped.

[0049] The shape and orientation of electrode 411 determine the distribution of the electric field it generates. By using a plate-shaped electrode 411 parallel to the axial direction, when a voltage is applied, the electric field lines generated are mainly concentrated and strong on both sides of the plate surface of electrode 411 (i.e., in the horizontal direction). This electric field configuration can more effectively apply a horizontal force to vertically falling ions, making the control of the horizontal velocity of ions more direct and significant, and consequently, the control of the horizontal velocity of free radicals also more direct and significant.

[0050] In some embodiments, the electrode feeder 413 is connected to the upper part of the electrode 411; the electrode feeder 413 is electrically connected to the voltage control module via a wire; the second cover plate 40 is provided with a cable management groove, the groove opening of the cable management groove is located on the upper surface of the second cover plate 40, and the wire is housed in the cable management groove.

[0051] The bottom end of the electrode feeder 413 (e.g., a metal rod) is fixed to the upper part (e.g., the top center) of the electrode 411, such as by welding or threading. The top end of the electrode feeder 413 passes through the insulating layer 412.

[0052] Electrode feeders 413 are electrically connected to the voltage control module via wires. To simplify the wiring of the plasma equipment and prevent wire interference or accidental short circuits, recessed cable management grooves are machined on the upper surface of the second cover plate 40. These cable management grooves start from the exit point of each electrode feeder 413, converge, and lead to an electrical connection area at the edge of the second cover plate 40. All connecting wires are housed in their respective cable management grooves and finally led out to the external voltage control module through the electrical connection area.

[0053] Optionally, an openable and closable protective cover can be installed at the opening of the cable tray to protect the wires inside. The protective cover can be opened and closed by sliding or rotating. Alternatively, the protective cover can be detachably connected to the second cover plate 40.

[0054] In some embodiments, the second cover plate 40 is provided with a mounting hole, the opening of which is located on the upper surface of the second cover plate 40, and the acceleration module 41 is detachably installed in the mounting hole.

[0055] The mounting hole is a blind hole. The shape and size of the mounting hole are adapted to the external contour of the acceleration module 41. For example, if the acceleration module 41 is rectangular, the mounting hole is a flat rectangular blind hole. The acceleration module 41, as an independent prefabricated component, can be integrally and detachably inserted and fixed in the mounting hole. The detachable connection method can be a fastening connection, a damping connection, a snap-fit, or a top-pressing mechanism using pressure plate screws.

[0056] In this embodiment, since the acceleration module 41 is designed to be detachable, when the acceleration module 41 is inspected or replaced, it is not necessary to remove the entire second cover plate 40 or perform a large-scale disassembly, so that the old acceleration module 41 can be taken out, which greatly reduces the maintenance cost.

[0057] Please refer to Figure 5 In some embodiments, the first cover plate 10 is provided with a cooling gas channel 11, which guides the cooling gas to flow through the first cover plate 10 and toward the outer wall of the dielectric cylinder 20. During plasma generation, a large amount of heat accumulates on the wall of the dielectric cylinder 20. In this embodiment, by introducing a cooling gas flow, the cooling gas carries away the heat of the first cover plate 10 as it flows within the cooling gas channel 11, and the cooling gas, after flowing out of the cooling gas channel 11, can flow along the outer wall of the dielectric cylinder 20 to cool the dielectric cylinder 20.

[0058] In some examples, the inlet 111 of the cooling gas channel 11 is located on the upper surface of the first cover plate 10 and is positioned close to the central axis of the plasma device. Typically, the inlet 131 of the process gas channel 13 is located at the center of the upper surface of the first cover plate 10, and the inlet 111 of the cooling gas channel 11 can be positioned adjacent to the inlet 131 of the process gas channel 13. The distance between the inlet 111 of the cooling gas channel 11 and the inlet 131 of the process gas channel 13 can be set according to actual needs.

[0059] The outlet 112 of the cooling gas channel 11 is located on the lower surface of the first cover plate 10 and corresponds to the periphery of the medium cylinder 20; there are multiple outlets 112, which are distributed at intervals along the circumference of the medium cylinder 20. The outlet 132 of the process gas channel 13 is located at the center of the lower surface of the first cover plate 10.

[0060] In this embodiment, the cooling gas enters from the inlet 111, which is closer to the center, and is distributed to the branches leading to each outlet 112. Subsequently, the cooling gas is blown evenly from the multiple outlets 112 onto the entire circumferential outer wall of the medium cylinder 20, ensuring the uniformity of the temperature field of the medium cylinder 20 along the circumference. This further ensures the symmetry of the electromagnetic field excited by the coil 30 surrounding it in spatial distribution, which is ultimately conducive to the formation of a more uniform plasma in the plasma generation space 21.

[0061] Please refer to Figure 5 In some embodiments, the first cover plate 10 is provided with a coolant channel 12, which extends circumferentially along the first cover plate 10. The coolant channel may be generally annular or spiral. The inlet 121 and outlet 122 of the coolant channel 12 are located on the side of the first cover plate 10, and the inlet 121 is spaced above the outlet 122.

[0062] In this embodiment, the specific heat capacity of the cooling liquid (usually deionized water or a special coolant) is much higher than that of the gas. Therefore, the heat exchange efficiency of liquid cooling is high, which can quickly and massively remove the radiative and conductive heat absorbed by the first cover plate 10 from the plasma generation space 21, effectively controlling the temperature of the first cover plate 10. The arrangement of high inlet and low outlet utilizes the gravity of the fluid, which is conducive to the natural flow of coolant in the channel. The circumferentially extended channel design maximizes the heat exchange area, while the inlet and outlet are located on the side, which facilitates connection with external cooling pipes and does not interfere with other structures on the upper part of the plasma equipment.

[0063] Other configurations of the plasma device in the above embodiments can be derived from various technical solutions now and in the future known to those skilled in the art, and will not be described in detail here.

[0064] In the description of this specification, it should be understood that the terms "center," "longitudinal," "transverse," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this disclosure and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this disclosure.

[0065] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this disclosure, "multiple" means two or more, unless otherwise explicitly specified.

[0066] In this disclosure, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this disclosure according to the specific circumstances.

[0067] In this disclosure, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0068] The foregoing disclosure provides many different implementations or examples for carrying out different structures of this disclosure. To simplify the disclosure, specific examples of components and arrangements have been described above. Of course, these are merely examples and are not intended to limit the scope of this disclosure. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various implementations and / or arrangements discussed.

[0069] The above description is merely a specific embodiment of this disclosure, but the scope of protection of this disclosure is not limited thereto. Any person skilled in the art can easily conceive of various variations or substitutions within the technical scope disclosed in this disclosure, and these should all be included within the scope of protection of this disclosure. Therefore, the scope of protection of this disclosure should be determined by the scope of the claims.

Claims

1. A plasma device, characterized in that, include: Medium cylinder; The first cover plate is installed on the upper part of the dielectric cylinder, and together with the dielectric cylinder, they form a plasma generation space; A coil, disposed on the outside of the dielectric cylinder, is used to excite the process gas in the plasma generation space into plasma; The housing is located below the medium cylinder; The second cover plate is connected to the lower part of the medium cylinder and covers the upper part of the box body, together with the box body forming a workpiece processing space; The second cover plate is provided with at least one acceleration module; wherein, the acceleration module includes: an electrode, an insulating layer and an electrode feeder, wherein, the insulating layer covers the electrode, and the electrode feeder is used to feed energy into the electrode to form an electric field, the electric field is used to adjust the horizontal velocity of ions in the plasma from the plasma space to the workpiece processing space, thereby adjusting the horizontal velocity of free radicals in the plasma; The grille is located below the acceleration module and above the workpiece processing space.

2. The plasma device according to claim 1, characterized in that, The acceleration module is multiple, and the multiple acceleration modules are spaced apart and evenly distributed along a preset circumference.

3. The plasma device according to claim 2, characterized in that, The diameter of the preset circumference is larger than the diameter of the space in the workpiece processing space.

4. The plasma device according to claim 2, characterized in that, Also includes: A voltage control module is electrically connected to the electrode feeders of the plurality of acceleration modules to control the intensity of the electric field formed by the electrodes of the plurality of acceleration modules.

5. The plasma device according to claim 2, characterized in that, The plurality of the acceleration modules are symmetrically distributed about the longitudinal center plane of the plasma device; Alternatively, the multiple acceleration modules may be symmetrically distributed about the transverse center plane of the plasma device.

6. The plasma device according to claim 2, characterized in that, The electrode is flat and parallel to the axis of the plasma device.

7. The plasma device according to claim 4, characterized in that, The electrode feeder is connected to the upper part of the electrode; The electrode feeder is electrically connected to the voltage control module via a wire; The second cover plate is provided with a cable management groove, the opening of which is located on the upper surface of the second cover plate, and the wire is received into the cable management groove.

8. The plasma device according to claim 1, characterized in that, The second cover plate is provided with mounting holes, the openings of which are located on the upper surface of the second cover plate, and the acceleration module is detachably installed in the mounting holes.

9. The plasma device according to claim 1, characterized in that, The first cover plate is provided with a cooling gas channel, which is used to guide the cooling gas to flow through the first cover plate and to the outer wall of the medium cylinder.

10. The plasma device according to claim 9, characterized in that, The air inlet of the cooling gas channel is located on the upper surface of the first cover plate and is positioned close to the central axis of the plasma device. The outlet of the cooling gas channel is located on the lower surface of the first cover plate and corresponds to the periphery of the medium cylinder; there are multiple outlets, and the multiple outlets are distributed at intervals along the circumference of the medium cylinder.

11. The plasma device according to claim 1, characterized in that, The first cover plate is provided with a coolant channel, which extends circumferentially along the first cover plate; The inlet and outlet of the coolant channel are located on the side of the first cover plate, and the inlet is located above the outlet at intervals.

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