Plasma processing apparatus, radical concentration adjusting method, and application

Abstract

The application relates to a kind of plasma processing equipment, free radical concentration regulation method and application, the plasma processing equipment includes: tube body, the tube body is used to accommodate process gas and forms plasma reaction space;Shielding structure, the shielding structure is arranged around the tube body;Split coil, the split coil is arranged around the shielding structure, including coil main body, connecting piece and conducting piece, the conducting piece, the connecting piece and the coil main body are sequentially electrically connected to form radio frequency current loop;The position of the connecting piece clamping the coil main body can be changed, to adjust the radial position of the coil main body relative to the tube body;The relative position of the conducting piece and the connecting piece along the tube body axial direction can be adjusted, to adjust the position of the coil main body along the tube body axial direction.Thereby flexible regulation to free radical concentration can be realized, and process performance is improved.

Description

Technical Field

[0001] This application mainly relates to the field of plasma equipment technology, and in particular to a plasma processing device, a free radical concentration adjustment method and its application. Background Technology

[0002] Inductively Coupled Plasma Etcher (ICP) equipment primarily dissociates gases and then transports them to the wafer surface for performance processing. With the advancement of semiconductor manufacturing processes, higher demands are placed on equipment efficiency. To improve wafer processing efficiency, current methods mainly involve increasing RF operating power and increasing the flow rate of process gases to enhance the total amount of process gas dissociation, thereby increasing the generation of free radicals and ultimately improving the free radical concentration within the equipment, thus optimizing process performance.

[0003] However, this method still has the following shortcomings: high power and high flow rate operating parameters will lead to increased heat generated during equipment operation, which will put greater pressure on the equipment's heat dissipation capacity and component temperature resistance, and reduce the stability of equipment operation.

[0004] Furthermore, existing inductively coupled plasma (ICP) equipment uses a fixed-installation structure for its coil circuits. Once installed, the coil's axial and radial positions relative to the tube and shielding structure cannot be adjusted, resulting in fixed values ​​for the free radical propagation path and the electromagnetic field strength generated by the coil. This makes it difficult to adapt to the free radical concentration control requirements of different processes and limits the flexibility of process parameter control; the available process control window is also narrow. Summary of the Invention

[0005] One objective of this application is to provide a plasma processing device, a free radical concentration adjustment method, and its application, which solves the problems in the prior art where inductively coupled plasma devices rely on high radio frequency operating power and large process gas flow rate to increase free radical concentration, resulting in increased heat load, reduced operational stability, fixed coil circuit position, difficulty in adjusting free radical transmission loss and electromagnetic field strength, and narrow process control window.

[0006] According to one aspect of this application, a plasma processing apparatus is provided, the plasma processing apparatus comprising: A tube body, which is used to contain process gases and form a plasma reaction space; A shielding structure is provided around the tube body; The split coil is arranged around the shielding structure and includes a coil body, a connector, and a conductive component. The conductive component, the connector, and the coil body are sequentially electrically connected to form a radio frequency current loop. The position of the connector holding the coil body can be changed to adjust the radial position of the coil body relative to the tube body; The relative positions of the conductive element and the connecting element along the axial direction of the tube are adjustable, so as to adjust the position of the coil body along the axial direction of the tube.

[0007] Optionally, the connector is provided with a plurality of clamping members, which clamp the coil body from the upper and lower sides.

[0008] Optionally, the conductive element is provided with an elongated slot, and the conductive element is connected to the connector through the elongated slot.

[0009] Optionally, the length of the elongated slot extends along the axial direction of the tube body.

[0010] Optionally, the conductive element can be slid relative to the connector along the length of the long slot, causing the coil body to move axially along the tube body, thereby changing the length of the free radical transport path from the generation region to the processing region.

[0011] Optionally, the plasma processing equipment further includes a coil fixing device, which is fixedly installed on the shielding structure to fix the split coil to the outside of the shielding structure.

[0012] Optionally, the coil fixing device includes a pad and a cap. The pad is disposed between the shielding structure and the coil body. The pad can be replaced with different thicknesses to adapt to different radial positions of the coil body.

[0013] Optionally, the pad and the cap are made of insulating material to provide electrical isolation between the radio frequency current loop and the shielding structure.

[0014] Optionally, both the pad and the cap are provided with through holes. Fasteners pass through the through holes in the cap and the pad to lock the pad and the cap onto the shielding structure, so that the pad and the cap cooperate to fix the coil body.

[0015] According to another aspect of this application, a method for adjusting the concentration of free radicals is also provided, applied to the plasma processing equipment as described above, comprising the following steps: Determine the target free radical concentration based on the target process; The current free radical concentration is compared with the target free radical concentration to determine the direction of change in the free radical concentration; Based on the direction of change in the free radical concentration, the clamping position of the connector on the coil body is changed to adjust the radial position of the coil body relative to the tube; and / or, The relative positions of the conductive element and the connecting element along the axial direction of the tube are changed to adjust the position of the coil body along the axial direction of the tube. The coil body after adjustment is fixed by a coil fixing device.

[0016] Optionally, the coil fixing device includes a pad and a cap, and fixing the adjusted coil body by the coil fixing device includes: Replace the pad with a pad of the corresponding thickness in the radial position after adjustment, so that the pad supports the coil body; Place the cap on the outside of the coil body, and then tighten the fasteners by passing them through the through holes on the pad and the cap in sequence, so as to fix the coil body in the adjusted position.

[0017] Optionally, when changing according to the direction of change in the free radical concentration, it includes: When the change of direction indicates an increase in concentration, the position of the connector holding the coil body is changed in the direction of decreasing the radial distance between the coil body and the tube body, and / or the relative position of the conductive element and the connector is changed in the direction of approaching the process area; When the change of direction indicates a decrease in concentration, the position of the connector holding the coil body is changed in the direction of increasing the radial distance between the coil body and the tube, and / or the relative position of the conductive element and the connector is changed in the direction away from the process area.

[0018] According to another aspect of this application, the use of the plasma processing equipment as described above in semiconductor wafer processing is also provided, wherein the electromagnetic field generated by the split coil dissociates the process gas introduced into the tube to form free radicals, and the concentration of the free radicals reaching the wafer surface is changed by adjusting the radial position and / or axial position of the coil body relative to the tube.

[0019] Compared with existing technologies, the plasma processing equipment provided in this application includes: a tube body for containing process gas and forming a plasma reaction space; a shielding structure surrounding the tube body; and a split-type coil surrounding the shielding structure, including a coil body, a connector, and a conductive element, wherein the conductive element, the connector, and the coil body are sequentially electrically connected to form a radio frequency current loop; the position of the connector clamping the coil body is changeable to adjust the radial position of the coil body relative to the tube body; the relative position of the conductive element and the connector along the axial direction of the tube body is adjustable to adjust the position of the coil body along the axial direction of the tube body. This enriches the control paths for free radical concentration, improves process performance, reduces the equipment's dependence on high radio frequency operating power and large process gas flow rates, thereby reducing the equipment's operating heat load and improving operational stability. Attached Figure Description

[0020] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the specific embodiments of this application will be described in detail below with reference to the accompanying drawings, wherein: Figure 1 A schematic cross-sectional view of a plasma device cavity structure provided according to one aspect of this application is shown. Figure 2 This is a structural schematic diagram showing the view of the plasma device coil installation in one embodiment of the present application; Figure 3 This illustration shows a schematic diagram of a split coil structure in one embodiment of this application; Figure 4 This illustration shows a schematic diagram of a coil radial position adjustment structure in one embodiment of this application; Figure 5 This diagram shows a structural schematic of the clamping member in one embodiment of the present application; Figure 6 This diagram shows a structural schematic of a long slot hole in one embodiment of this application; Figure 7 This invention provides a schematic diagram of the coil fixing device structure in one embodiment of the present application. Figure 8 A flowchart illustrating a method for adjusting free radical concentration according to another aspect of this application is shown. Figures 9(a) to 9(c) show schematic diagrams of simulation results for different radial distances in one embodiment of this application; Figure 10 This diagram illustrates the principle of the free radical generation region and transport loss path in a plasma processing device according to an embodiment of this application.

[0021] The reference numerals in the attached figures are explained as follows: 10 - Tube body, 20 - Shielding structure; 30-Separate coil, 3021-Clamping component, 301-Coil body, 302-Connector, 303-Conductive component, 3031-Long slot, 3032-Bolt; 40-Coil fixing device, 401-Plate, 402-Cap; 50-Top cover plate, 60-Spray plate, 70-Cavity, 80-Base, 90-RF generator.

[0022] The same or similar reference numerals in the accompanying drawings represent the same or similar parts. Detailed Implementation

[0023] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the specific embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0024] Many specific details are set forth in the following description in order to provide a full understanding of this application. However, this application may also be implemented in other ways different from those described herein, and therefore this application is not limited to the specific embodiments disclosed below.

[0025] In the description of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0026] Furthermore, the terms “up,” “down,” “left,” “right,” “top,” “bottom,” “horizontal,” and “vertical” used in the following description should be understood as the orientations shown in the paragraph and related figures. This relative terminology is for illustrative purposes only and does not imply that the described device must be manufactured or operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0027] It is understood that although terms such as “first,” “second,” “third,” etc., may be used here to describe various pipes, channels, components, areas, layers, and / or parts, these components, areas, layers, and / or parts should not be limited by these terms, and these terms are only used to distinguish different pipes, channels, components, areas, layers, and / or parts.

[0028] refer to Figures 1-3The plasma processing equipment includes: a tube body 10 for containing process gas and forming a plasma reaction space; a shielding structure 20 surrounding the tube body 10; and a split coil 30 surrounding the shielding structure 20, including a coil body 301, a connector 302, and a conductive element 303, wherein the conductive element 303, the connector 302, and the coil body 301 are sequentially electrically connected to form a radio frequency current loop; the position of the connector 302 clamping the coil body 301 is changeable to adjust the radial position of the coil body 301 relative to the tube body 10; the relative position of the conductive element 303 and the connector 302 along the axial direction of the tube body 10 is adjustable to adjust the position of the coil body 301 along the axial direction of the tube body 10.

[0029] The tube 10 receives the process gas. After entering from the top of the tube 10, the process gas is dissociated into plasma and free radicals inside the tube 10 and then transported downwards. The outer periphery of the tube 10 is surrounded by a shielding structure 20, which separates the tube 10 from the split coil 30 and forms the mounting boundary of the split coil 30. The shielding structure 20 may be made of metal and grounded to confine the radio frequency electromagnetic field within the coupling area between the tube 10 and the split coil 30, preventing radio frequency energy from radiating and leaking into the external space, while also shielding the plasma stability from external electromagnetic interference.

[0030] In one embodiment of this application, the shielding structure 20 may be a Faraday shielding cylinder coaxially sleeved outside the tube body 10. This shielding cylinder is made of conductive metal and connected to the equipment housing for grounding. Multiple slots extending axially along the tube body 10 are formed on the cylinder wall, and these slots are spaced apart along the circumference of the shielding cylinder. It should be noted that in other embodiments, the shielding structure 20 may also be a metal shielding cover without slots or other forms of grounding shielding components. These shielding components are also arranged around the tube body 10, providing an installation reference for the split coil 30 while simultaneously achieving electromagnetic shielding.

[0031] The separate coil 30 is located outside the shielding structure 20. The relative arrangement between the shielding structure 20 and the tube 10, and between the shielding structure 20 and the separate coil 30, allows the separate coil 30 to adjust its distance relative to the tube 10 by changing its position without entering the reaction space, thereby altering the concentration of free radicals. Specifically, as... Figure 3 and Figure 4As shown, the split-type coil 30 adopts a detachable and relatively adjustable loop structure, specifically including a coil body 301, a connector 302, and a conductive element 303, which are electrically connected in sequence to form a radio frequency current loop. The radio frequency current flows from the radio frequency source into the coil body 301 through the conductive element 303 and the connector 302. The coil body 301 generates an alternating electromagnetic field around the shielding structure 20. According to the principle of electromagnetic induction, this electromagnetic field penetrates the tube wall of the tube 10 and induces an alternating electric field inside the cavity. The electric field accelerates electrons to collide with process gas molecules, causing them to dissociate and generate plasma containing free radicals.

[0032] The coil body 301 is the inductive part arranged around the shielding structure 20 in the radio frequency current loop. A connector 302 is located between the conductive element 303 and the coil body 301, connecting them into a single coil loop. The connector 302 can be formed as a plate-like component, extending vertically along the axial direction of the tube 10. The connector 302 performs two functions: electrically, it acts as a conductor to transmit radio frequency current from the conductive element 303 to the coil body 301, ensuring electrical continuity of the entire coil loop; mechanically, it provides an interface for position adjustment, allowing the connector 302 to change the position holding the coil body 301, thereby adjusting the radial position of the coil body 301 relative to the tube 10. When the coil body 301 is adjusted towards the tube 10, the distance between the coil body 301 and the tube 10 decreases, the electromagnetic field coupling is enhanced, the degree of dissociation of the process gas is increased, and the amount of free radicals generated increases; when the coil body 301 is adjusted away from the tube 10, the electromagnetic field coupling is weakened, and the amount of free radicals generated is reduced accordingly, thereby adapting to the free radical concentration required by the target process.

[0033] The conductive element 303 is a conductive component that introduces radio frequency (RF) current from the RF source into the coil circuit. The conductive element 303 can be a long, strip-shaped conductive strip extending along the axial direction of the tube 10. Its lower end is electrically connected to the coil body 301 via a connector 302, and its upper end is horizontally bent away from the tube 10 to form a feed terminal for connection to the RF source. The split-type coil 30 includes two conductive elements, serving as the RF current feed-in and return terminals respectively, forming a complete RF current circuit together with the connector 302 and the coil body 301. The relative position of the conductive element 303 and the connector 302 along the axial direction of the tube 10 can be adjusted, thereby changing the position of the coil body 301 along the axial direction of the tube 10. Since free radicals generated in the region corresponding to the coil body 301 need to be transported downwards along the tube 10 to the processing area, during the transport process, free radicals will collide and recombine with the tube wall and the surface of the structural components, resulting in losses. The axial position of the coil body 301 determines the length of the free radical transport path: when the relative position of the conductive component 303 and the connecting component 302 is adjusted to move the coil body 301 closer to the processing area, the transport path is shortened, the losses are reduced, and the concentration of free radicals reaching the processing area increases; conversely, the concentration decreases.

[0034] It should be noted that the conductive element is made of a metallic material with excellent conductivity, such as copper or copper alloy, to reduce resistance loss during radio frequency current transmission; in other embodiments, the conductive element may also be made of other good conductor materials such as aluminum or aluminum alloy. To further reduce contact resistance and prevent surface oxidation, the surface of the conductive strip may be plated with a silver or nickel layer.

[0035] The aforementioned split structure places the mechanical adjustment positions between the connector 302 and the coil body 301 (radial adjustment) and between the conductive part 303 and the connector 302 (axial adjustment), allowing the same split coil 30 to have adjustment capabilities in both radial and axial dimensions. Furthermore, each dimension of adjustment has an independent structural interface, preventing interference and ensuring simple and reliable adjustment operation. Specifically, radial adjustment controls the generation of free radicals by changing the strength of electromagnetic field coupling, while axial adjustment controls the transmission loss of free radicals by changing the transmission path length, thereby achieving flexible adjustment of the free radical concentration.

[0036] It should be noted that the axial position adjustment and radial position adjustment of the coil circuit can be performed independently or in combination. For example, the electromagnetic field strength can be set first by the clamping position between the connector 302 and the coil body 301, and the free radical transport stroke can be set by the relative position between the connector 302 and the conductive part 303, so as to match the target free radical concentration from the two dimensions of generation amount and transport loss.

[0037] Compared to traditional methods that increase free radical concentration by increasing RF power and gas flow rate, which leads to high heat, high energy consumption, and high operating costs, this application's embodiment adjusts the concentration by changing both the generation rate and transmission loss through purely mechanical structural position adjustment. This eliminates the need to change process power and gas flow rate, avoiding the heat load and increased costs associated with high power. Furthermore, by controlling transmission loss through axial adjustment and controlling the generation rate through radial adjustment, the device possesses the ability to regulate the concentration from both the generation rate and transmission loss perspectives.

[0038] In one embodiment of this application, as Figure 5 As shown, the connector 302 is provided with a plurality of clamping members 3021, which clamp the coil body 301 from the upper and lower sides.

[0039] The connector 302 clamps the coil body 301 via a clamping member 3021, which can be a fixing clip. Preferably, the fixing clip is arranged on the upper and lower sides of the coil body 301, so that the coil body 301 is subject to relative upper and lower limiting effects at the clamping point. When it is necessary to adjust the radial position of the coil body 301, the fixing clip is loosened to release the limiting effect on the coil body 301, the position of the connector 302 clamping the coil body 301 is changed, and then it is re-clamped to change the coil body 301 to be fixed in a new radial position.

[0040] In one specific embodiment of this application, 12 fixing clips are evenly distributed along the circumference of the exterior of the split coil 30. These 12 fixing clips together constitute the connection structure of the connector 302 that clamps the coil body 301. The 12 fixing clips, evenly distributed along the circumference, constrain the coil body 301 from multiple directions. During radial adjustment, the clamping constraints of the 12 fixing clips can be released first, allowing the coil body 301 to move radially relative to the tube 10. After confirming that the circumferential spacing meets the target installation state, the clamps are sequentially restored, ensuring that the coil body 301 remains coaxial with the tube 10 before and after radial adjustment. This avoids coil skewing due to local adjustments, which could affect the circumferential uniformity of the electromagnetic field. The radial adjustment range is 5mm. Within this 5mm range, the radial distance D between the coil body 301 and the tube 10 can be continuously adjusted, precisely controlling the electromagnetic field coupling strength.

[0041] In one embodiment of this application, as Figure 6 As shown, the conductive component 303 is provided with an elongated slot 3031, and the conductive component 303 is connected to the connector 302 through the elongated slot 3031.

[0042] After the connection is loosened, the connector 302 can move relative to the conductive element along the elongated slot 3031; upon reaching the target position, it is retightened to define the axial installation position while maintaining electrical connection. This connection can be achieved using a bolt 3032 passing through the elongated slot 3031 or other connection methods known to those skilled in the art that combine conductivity and adjustability. For example, changing the relative installation position of the conductive element and the connector 302 along the elongated slot 3031 can cause the coil body 301 to move axially along the tube 10, bringing the coil body 301 closer to or further away from the processing area, while the elongated slot 3031 provides a continuous adjustment path for the tightening position.

[0043] The elongated slot 3031 is an elongated through-hole penetrating the conductive element 303. A fastening element passes through the slot 3031 to press the conductive element 303 against the connector 302. When the fastening element is loose, the conductive element 303 can move relative to the connector 302 along the length of the slot 3031. After reaching the target position, the fastening element is tightened, and the clamping force causes the contact surfaces of the conductive element 303 and the connector 302 to fit tightly together, thereby fixing the conductive element 303 in that position. Since the conductive element 303 itself is a conductive component and is in direct contact with the connector 302, this clamping fixation achieves mechanical positioning while maintaining the electrical connection between the conductive element 303 and the connector 302, allowing radio frequency current to be continuously transmitted from the conductive element 303 to the connector 302.

[0044] The elongated slot 3031 provides a continuous adjustment path for the relative position between the conductive element 303 and the connector 302, so that the relative position between the two is not limited to discrete fixed points, but can be continuously adjusted within the length range of the elongated slot 3031.

[0045] Following the above embodiment, the length direction of the elongated slot 3031 extends along the axial direction of the tube body 10.

[0046] When the length extends along the axial direction of the tube 10, after the fastening element is loosened, the conductive element 303 can only slide relative to the connecting element 302 along the axial direction (i.e., the vertical direction) of the tube 10, and cannot move in the circumferential or radial direction. When the conductive element 303 moves upward or downward, it drives the coil body 301 to move synchronously along the axial direction of the tube 10, thereby changing the position of the coil body 301 in the axial direction of the tube 10.

[0047] By limiting the length of the long slot 3031 to extend along the axial direction of the tube 10, it is ensured that every displacement of the conductive element 303 is accurately converted into a positional change of the coil body 301 along the axial direction of the tube 10. The adjustment direction is singular and definite, and no unexpected motion components are introduced.

[0048] Continuing with the above embodiments, the conductive element 303 is slid relative to the connector 302 along the length direction of the long slot 3031, causing the coil body 301 to move axially along the tube 10, thereby changing the length of the free radical transport path from the generation region to the processing region.

[0049] After loosening the fastening element, the conductive element 303 is slid along the elongated slot 3031 towards the processing area. The conductive element 303, through the connector 302, drives the coil body 301 to move synchronously in this direction. The axial distance between the area where the free radicals are generated in the coil body 301 and the processing area is shortened. The path length required for the free radicals to travel from generation to reaching the processing area is thus shortened, reducing the number of collisions and recombinations with the tube wall and structural surface during transmission, lowering losses, and increasing the concentration of free radicals reaching the processing area. Conversely, when the conductive element 303 is slid along the elongated slot 3031 away from the processing area, the coil body 301 moves away from the processing area, lengthening the transmission path, increasing the number of collisions and recombinations, increasing losses, and lowering the concentration of free radicals reaching the processing area.

[0050] The length range of the long slot 3031 determines the maximum stroke of the coil body 301 axial movement. The maximum stroke can be 30mm, that is, the adjustable range of the long slot 3031 is ±15mm. The conductive part 303 can stop and lock at any position within this stroke, thereby continuously adjusting the length and concentration of the free radical transport path and covering the needs of different processes for changes in the length of the free radical transport path.

[0051] Continue to refer to Figure 1 and Figure 2 In one embodiment of this application, the plasma processing equipment further includes a coil fixing device 40, which is fixedly installed on the shielding structure 20 and used to fix the split coil 30 to the outside of the shielding structure 20.

[0052] The coil fixing device uses the shielding structure 20 as the installation reference, so that the split coil 30 remains coaxial with the tube 10 in the fixed state, ensuring that the coil position does not shift or loosen during long-term operation. At the same time, since the fixing device uses the coaxial shielding structure 20 as the installation reference, the coil can still restore the coaxial relationship with the tube 10 after each adjustment and refixation, and will not introduce eccentricity due to adjustment operation; thus ensuring that the electromagnetic field generated by the coil is uniformly distributed in the circumferential direction of the tube 10.

[0053] Following the above embodiments, as Figure 7As shown, the coil fixing device 40 includes a pad 401 and a cap 402. The pad 401 is disposed between the shielding structure 20 and the coil body 301. The pad 401 can be replaced with different thicknesses to adapt to different radial positions of the coil body 301.

[0054] The pad 401 has a replaceable structure. After adjusting the position of the coil body 301, a pad 401 of the appropriate thickness is selected according to the actual installation gap to adapt to different radial positions of the coil body 301. When the coil body 301 is adjusted radially away from the tube 10, the gap between the coil body 301 and the outer wall of the shielding structure 20 increases, and the original pad thickness can no longer fill the gap. At this time, a thicker pad is replaced, and the outer surface of the pad 401 moves outward to the inner side of the new position of the coil body 301, which just fills the increased gap and provides support. Conversely, when the coil body 301 is adjusted towards the tube 10, the gap decreases, and a thinner pad can be replaced. The thickness of the pad 401 corresponds one-to-one with the radial position of the coil body 301, and a set of pads of different thicknesses can be prefabricated for selection during adjustment. Through the cooperation of the cap and the pad, an installation limit is formed on the outside of the coil body 301, keeping the coil body 301 in the adjusted position and preventing it from shifting back under working vibration or thermal expansion.

[0055] In one embodiment of this application, the pad 401 and the cap 402 are made of insulating material to electrically isolate the radio frequency current loop from the shielding structure 20.

[0056] The pad 401 and cap 402 provide mechanical support and limit for the coil body 301. Simultaneously, the pad 401 and cap 402, made of insulating material, form an electrical barrier between the coil body 301 and the shielding structure 20. The pad 401 separates the inner side of the coil body 301 from the outer wall of the shielding structure 20, and the cap 402 separates the outer side of the coil body 301 from the external metal structure. This ensures that the radio frequency current can only flow along the designed circuit of the conductive component 303, connector 302, and coil body 301, and will not bypass to ground through the fixing device. It should be noted that the insulating material used for the pad 401 and cap 402 should meet the insulation performance and structural stability requirements of the equipment's operating environment. The specific type can be selected according to the operating conditions of the plasma processing equipment, such as engineering plastics or ceramics.

[0057] In one embodiment of this application, both the pad 401 and the cap 402 are provided with through holes. Fasteners pass through the through holes on the cap 402 and the pad 401 to lock the pad 401 and the cap 402 onto the shielding structure 20, so that the pad 401 and the cap 402 cooperate to fix the coil body 301.

[0058] The through holes on the pad 401 and the cap 402 are aligned during assembly. Fasteners pass through the cap 402 and pad 401 from the outside (towards the cap 402 side), pulling them towards the shielding structure 20. The axial clamping force generated by the fasteners causes the pad 401 (inner support) and the cap 402 (outer limiting member) to engage, securing the coil body 301 located between them and anchoring the entire coil fixing device to the shielding structure 20. The outside-to-inside penetration sequence (cap 402 first, then pad 401) is consistent with the equipment assembly direction, allowing operators to tighten and loosen the fasteners from outside the equipment without disassembling other components.

[0059] It should be noted that the fasteners can be screws or other detachable fasteners, so that when the coil position needs to be readjusted, the fasteners can be loosened, the cap removed, the pad 401 replaced, and the fasteners re-tightened. After the fasteners are tightened, the coil body 301 changes from a movable state to a fixed state, and operates stably in the new radial and / or axial position.

[0060] Figure 8 The diagram illustrates a flow chart of a free radical concentration adjustment method according to another aspect of this application, applied to the plasma processing equipment as described above, comprising the following steps: Step S11: Determine the target free radical concentration based on the target process.

[0061] The operator or equipment control process for implementing adjustments determines the target free radical concentration required to reach the wafer surface based on the desired process effects of semiconductor wafer processing. The target concentration can be determined based on process parameters such as etching rate, etching selectivity, or control requirements.

[0062] Step S12: Compare the current free radical concentration with the target free radical concentration to determine the direction of change in the free radical concentration.

[0063] The current free radical concentration reaching the wafer surface under the current process conditions is compared with the determined target free radical concentration: if the target free radical concentration is higher than the current free radical concentration, the direction is changed to increase the concentration; if the target free radical concentration is lower than the current free radical concentration, the direction is changed to decrease the concentration.

[0064] Step S13: According to the direction of change of the free radical concentration, change the clamping position of the connector on the coil body to adjust the radial position of the coil body relative to the tube; and / or, change the relative position of the conductive element and the connector along the axial direction of the tube to adjust the position of the coil body along the axial direction of the tube.

[0065] Radial adjustment alters the strength of the electromagnetic field and the amount of free radicals generated, while axial adjustment changes the transport distance and loss of free radicals from the generation region to the spray plate and wafer surface. For example, when increasing the free radical concentration is needed but the amount of free radicals generated is insufficient, the coil body is moved closer to the tube; when increasing the free radical concentration is needed but the transport loss is high, the coil body is moved closer to the spray plate; when decreasing the free radical concentration is needed, the opposite adjustment is performed. Radial and / or axial adjustments influence the concentration of free radicals reaching the wafer surface.

[0066] Step S14: Fix the adjusted coil body using the coil fixing device.

[0067] According to the free radical concentration adjustment method described in this embodiment, the amount of free radical generation can be changed by adjusting the radial position, and the free radical transport loss can be changed by adjusting the axial position, thereby matching the target free radical concentration without solely relying on high power and high flow rate.

[0068] In one embodiment of this application, the coil fixing device includes a pad and a cap. In step S14, the pad with a thickness corresponding to the adjusted radial position is replaced so that the pad supports the coil body. The cap is placed on the outside of the coil body, and fasteners are passed through the through holes on the pad and the cap in sequence to lock the coil body in the adjusted position.

[0069] After radial position adjustment, the gap between the coil body and the outer wall of the shielding structure changes. Based on the actual size of this gap, a shim of the target thickness matching this actual size is selected and replaced. That is, the original shim is removed, and a shim 401 of the target thickness, adapted to the adjusted gap, is installed, ensuring that the inner side of the shim 401 fits against the outer wall of the shielding structure and the outer side supports the coil body. Then, the cap is placed on the outside of the coil body, and fasteners are passed through the through holes in the cap and the shim in sequence and locked, fixing the coil body in the adjusted position from both the inner and outer radial sides.

[0070] In one embodiment of this application, in step S13, when the change direction indicates an increase in concentration, the position of the connector holding the coil body is changed along the direction of decreasing the radial distance between the coil body and the tube, and / or the relative position of the conductive element and the connector is changed along the direction closer to the process processing area; when the change direction indicates a decrease in concentration, the position of the connector holding the coil body is changed along the direction of increasing the radial distance between the coil body and the tube, and / or the relative position of the conductive element 303 and the connector is changed along the direction away from the process processing area.

[0071] When the direction of change indicates an increase in concentration, the position of the connector holding the coil body is changed along the direction that reduces the radial distance between the coil body and the tube to enhance electromagnetic field coupling and increase the amount of free radicals generated; and / or the relative position of the conductive parts and connectors is changed along the direction closer to the processing area to shorten the free radical transport path and reduce transport loss. These two operations can be performed individually or simultaneously to superimpose the concentration-enhancing effect.

[0072] When the direction of change indicates a decrease in concentration, the position of the connector holding the coil body is changed along the direction of increasing the radial distance between the coil body and the tube to weaken electromagnetic field coupling and reduce the amount of free radicals generated; and / or the relative position of the conductive part and the connector is changed along the direction away from the process area to extend the free radical transport path and increase the transport loss.

[0073] In the radial adjustment process, a fixed clamp is used as the clamping component. First, the fixed clamp is loosened to release the clamping constraint of the connector on the coil body. Then, the position of the connector clamping the coil body is changed, and after confirming the target radial position of the coil body relative to the tube, it is re-clamped. Preferably, the fixed clamps are arranged on the upper and lower sides of the connector. During adjustment, the upper and lower fixed clamps are loosened to allow the coil body to move smoothly at the clamping point. Figures 9(a) to 9(c) show the simulation comparison results of the electron density inside the tube under different radial distances D between the coil body and the tube. All three simulations were conducted under the same process conditions of 3000W RF power and 13.32Pa pressure, changing only the radial distance D between the coil body and the tube, thus verifying the influence of radial position adjustment on the degree of plasma dissociation. In Figures 9(a) to 9(c), the values ​​of D are D=12mm, D=10mm and D=5mm respectively. The simulation results show that the smaller D is, the stronger the induced electric field inside the tube, the more complete the ionization and dissociation of the process gas, and the more free radicals are generated.

[0074] Furthermore, multiple fixing clips are evenly distributed on the outside of the split coil. During radial adjustment, these clips are loosened, and the position of the connector holding the coil body is changed. Preferably, 12 fixing clips are evenly distributed on the outside of the split coil, and these 12 clips work together to maintain the circumferential installation state of the coil body. For example, the constraints of the 12 fixing clips can be released sequentially, the radial distance between the coil body and the tube can be adjusted as a whole, and after confirming that the circumferential position meets the target state, they can be re-clamped sequentially to reduce the coil body tilting caused by local pre-locking.

[0075] During axial adjustment, the conductive component has an elongated slot, the length of which extends axially along the tube body. After loosening the connection between the conductive component and the connector, the connector moves relative to the conductive component along the elongated slot, thereby causing the coil body to move axially along the tube body. Once the target position is reached, it is tightened again to maintain the conductive path of the radio frequency current flowing from the conductive component through the connector into the coil body.

[0076] By altering the relative positions of the conductive and connecting components along the elongated slot, the transmission distance of the coil body relative to the processing area can be changed. Shortening the stroke reduces the consumption of free radicals during transmission, while lengthening the stroke increases this consumption. For example, if it is determined that an increased free radical concentration is needed and the radial position already meets the target state, the transmission distance between the coil body and the processing area can be shortened without changing the radial position of the coil body relative to the tube, thus allowing for targeted adjustment of transmission loss.

[0077] According to another aspect of this application, the use of the plasma processing equipment as described above in semiconductor wafer processing is also provided, wherein the electromagnetic field generated by the split coil 30 dissociates the process gas introduced into the tube 10 to form free radicals, and the concentration of the free radicals reaching the wafer surface is changed by adjusting the radial position and / or axial position of the coil body 301 relative to the tube 10.

[0078] The plasma processing equipment includes a tube 10, a shielding structure 20, a split coil 30, an upper cover plate 50, and a spray plate 60. The split coil 30 includes a coil body 301, a connector 302, and a conductive component 303.

[0079] The top cover plate 50 is located at the top of the tube body 10 and is used to seal the upper opening of the tube body 10. Process gas enters the cavity of the tube body 10 through the gas inlet on the top cover plate 50; the top cover plate 50 also provides a closed interface for the upper structure, maintains the vacuum environment inside the tube body 10, and prevents external contaminants from entering the process area. Process gas is introduced into the plasma reaction space formed by the tube body 10, and radio frequency current flows into the coil body 301 through the conductive element 303 and the connector 302. The electromagnetic field generated by the coil body 301 dissociates the process gas to form free radicals. The spray plate 60 is located below the tube body 10 and above the cavity, and has a large number of vent holes distributed on the plate. After the free radicals are generated in the corresponding area of ​​the coil inside the tube body 10, they are transported downward under the action of the pressure gradient. When passing through the spray plate 60, they are redistributed by the vent holes on the plate and enter the lower cavity to reach the wafer surface in a uniform surface distribution.

[0080] like Figure 10As shown, process gas enters the tube body through the inlet port on the upper cover plate 50. Coils connected to an RF generator 90 are located on both sides of the tube body 10. The RF generator 90 supplies RF current to the coils. The electromagnetic field generated by the coils penetrates the tube wall and induces an electric field within the tube body, dissociating the process gas and generating free radicals in region A. The strength of the electromagnetic field can be changed by adjusting the radial position of the coils relative to the tube body, thereby controlling the amount of free radicals generated. A spray plate 60 is also located below the tube body 10, separating it from the lower chamber 70. Inside the chamber 70 is a base 80 extending upwards from the bottom, on which the wafer is placed for processing. During free radical transport, free radicals collide with the tube wall, spray plate surface, chamber wall, and base surface, causing losses, such as those occurring in region B. Therefore, the transport path length of free radicals from the generation region to the processing region can be changed by adjusting the position of the coils along the tube body axis, thereby controlling the transport loss.

[0081] In this application, specifically, the clamping position of the connector 302 on the coil body 301 is used to set the radial position of the coil body 301 relative to the tube 10, and the relative position of the conductive element 303 and the connector 302 is used to set the axial position of the coil body 301 along the tube 10. The radial position affects the strength of the electromagnetic field and the amount of free radicals generated, while the axial position affects the transmission distance from the free radical generation area to the spray plate 60 and the wafer surface. For example, when the wafer processing process requires an increased concentration of free radicals reaching the wafer surface, the coil body 301 can be moved closer to the tube 10 to increase free radical generation, and / or the coil body 301 can be moved closer to the spray plate 60 to reduce free radical transmission loss; after the position adjustment and fixing are completed, process gas is introduced and radio frequency current is applied for wafer processing.

[0082] According to the application described in this embodiment, by adjusting the position of the split coil 30, the free radical concentration on the wafer surface can be improved through two paths: increasing free radical generation and reducing free radical transport loss. This results in a better processing effect and reduces the heat, cost, and equipment stability pressure caused by simply using a high-power, high-flow-rate solution.

[0083] The basic concepts have been described above. Obviously, for those skilled in the art, the above disclosure is merely illustrative and does not constitute a limitation of this application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements, and corrections to this application. Such modifications, improvements, and corrections are suggested in this application, and therefore remain within the spirit and scope of the exemplary embodiments of this application.

[0084] Furthermore, this application uses specific terms to describe embodiments of the application. For example, "an embodiment," "one embodiment," and / or "some embodiments" refer to a particular feature, structure, or characteristic related to at least one embodiment of the application. Therefore, it should be emphasized and noted that "an embodiment," "one embodiment," or "an alternative embodiment" mentioned twice or more in different locations in this specification do not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of the application can be appropriately combined.

[0085] In some embodiments, numbers describing the quantity of components and attributes are used. It should be understood that such numbers used in the description of embodiments are modified in some examples with the terms "approximately," "approximately," or "generally." Unless otherwise stated, "approximately," "approximately," or "generally" indicates that the numbers are allowed to vary by ±20%. Accordingly, in some embodiments, the numerical parameters used in the specification and claims are approximate values, which may be changed depending on the characteristics required by individual embodiments. In some embodiments, numerical parameters should take into account specified significant digits and employ a general method of digit reservation. Although the numerical ranges and parameters used to confirm their breadth of scope in some embodiments of this application are approximate values, in specific embodiments, such values ​​are set as precisely as feasible.

Claims

1. A plasma processing device, characterized in that, The plasma processing equipment includes: A tube body, which is used to contain process gases and form a plasma reaction space; A shielding structure is provided around the tube body; The split coil is arranged around the shielding structure and includes a coil body, connecting parts and conductive parts. The conductive parts, connecting parts and coil body are sequentially electrically connected to form a radio frequency current loop. The position of the connector clamping the coil body can be changed to adjust the radial position of the coil body relative to the tube body; The relative positions of the conductive component and the connecting component along the axial direction of the tube are adjustable, thereby adjusting the position of the coil body along the axial direction of the tube.

2. The plasma processing equipment according to claim 1, characterized in that, The connector is provided with multiple clamping members, which clamp the coil body from the upper and lower sides.

3. The plasma processing equipment according to claim 1, characterized in that, The conductive component is provided with an elongated slot, and the conductive component is connected to the connector through the elongated slot.

4. The plasma processing equipment according to claim 3, characterized in that, The length of the long slot extends along the axial direction of the tube body.

5. The plasma processing equipment according to claim 4, characterized in that, The conductive element is slid relative to the connector along the length of the long slot, causing the coil body to move axially along the tube body, thereby changing the length of the free radical transport path from the generation region to the processing region.

6. The plasma processing apparatus according to claim 1, characterized in that, The plasma processing equipment also includes a coil fixing device, which is fixedly installed on the shielding structure to fix the split coil to the outside of the shielding structure.

7. The plasma processing apparatus according to claim 6, characterized in that, The coil fixing device includes a pad and a cap. The pad is disposed between the shielding structure and the coil body. The pad can be replaced with different thicknesses to adapt to different radial positions of the coil body.

8. The plasma processing apparatus according to claim 7, characterized in that, The pad and the cap are made of insulating material to provide electrical isolation between the radio frequency current loop and the shielding structure.

9. The plasma processing apparatus according to claim 7, characterized in that, Both the pad and the cap have through holes. Fasteners pass through the through holes in the cap and the pad to lock the pad and the cap onto the shielding structure, so that the pad and the cap cooperate to fix the coil body.

10. A method for adjusting free radical concentration, applied to a plasma processing device as described in any one of claims 1 to 9, characterized in that, Includes the following steps: Determine the target free radical concentration based on the target process; The current free radical concentration is compared with the target free radical concentration to determine the direction of change in the free radical concentration; Based on the direction of change in the free radical concentration, the clamping position of the connector on the coil body is changed to adjust the radial position of the coil body relative to the tube; and / or, The relative positions of the conductive element and the connecting element along the axial direction of the tube are changed to adjust the position of the coil body along the axial direction of the tube. The coil body after adjustment is fixed by a coil fixing device.

11. The free radical concentration adjustment method according to claim 10, wherein the coil fixing device includes a pad and a cap, and the fixing of the adjusted coil body by the coil fixing device includes: Replace the pad with a pad of the corresponding thickness in the radial position after adjustment, so that the pad supports the coil body; Place the cap on the outside of the coil body, and then tighten the fasteners by passing them through the through holes on the pad and the cap in sequence, so as to fix the coil body in the adjusted position.

12. The method for adjusting free radical concentration according to claim 10, characterized in that, When the direction of change in the free radical concentration is changed accordingly, it includes: When the change of direction indicates an increase in concentration, the position of the connector holding the coil body is changed in the direction of decreasing the radial distance between the coil body and the tube body, and / or the relative position of the conductive element and the connector is changed in the direction of approaching the process area; When the change of direction indicates a decrease in concentration, the position of the connector holding the coil body is changed in the direction of increasing the radial distance between the coil body and the tube, and / or the relative position of the conductive element and the connector is changed in the direction away from the process area.

13. Use of a plasma processing apparatus as described in any one of claims 1 to 9 in semiconductor wafer processing, wherein the electromagnetic field generated by the split coil dissociates the process gas introduced into the tube to form free radicals, and the concentration of the free radicals reaching the wafer surface is changed by adjusting the radial and / or axial position of the coil body relative to the tube.

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