Inductive coupling device and plasma equipment

Abstract

The invention provides an inductive coupling device and plasma equipment, the inductive coupling device is used for coupling radio frequency energy into a process chamber through a dielectric window, the inductive coupling device comprises a radio frequency coil arranged on the outer side of the dielectric window, the surface of the radio frequency coil is provided with a silver coating, the inductive coupling device further comprises a sealing assembly, and the sealing assembly is arranged on the outer side of the dielectric window. A sealing space is formed between the sealing assembly and the dielectric window so that the radio frequency coil can be contained in the sealing space, the sealing assembly is provided with a gas inlet channel and a gas exhaust channel, the gas inlet channel is communicated with a protective gas source so that protective gas can be filled into the sealing space, and the gas exhaust channel is communicated with the gas exhaust channel. The air exhaust channel is communicated with the air exhaust assembly so as to exhaust gas in the sealed space, and the protective gas does not react with the silver plating layer so as to prevent the silver plating layer from being corroded. The method can solve the problems that the plasma density is reduced, the uniformity is deteriorated and the process stability is reduced.

Description

Technical Field

[0001] This invention relates to the field of plasma technology, and more particularly to an inductive coupling device and plasma equipment. Background Technology

[0002] Plasma technology plays a crucial role in semiconductor manufacturing, applicable to various semiconductor processes such as etching, resist stripping, and thin-film deposition. ICP (Inductively Coupled Plasma) equipment uses a radio frequency (RF) power supply connected to an RF coil to generate an alternating magnetic field within the reaction chamber. This induces a ring current, ionizing the gas within the process chamber and producing high-density plasma.

[0003] However, after a period of use, the stability and uniformity of plasma distribution in existing ICP equipment tend to decrease, and the plasma density also tends to decrease even when conditions such as RF power supply and process gas remain unchanged. Summary of the Invention

[0004] To address the problems of decreased plasma density, deteriorated uniformity, and reduced process stability, this invention provides an improved inductive coupling device and plasma equipment.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: The first aspect of the present invention provides an inductive coupling device for coupling radio frequency energy into a process chamber through a dielectric window to ionize process gas in the process chamber into plasma. The inductive coupling device includes a radio frequency coil disposed outside the dielectric window, the surface of which is coated with a silver layer. The inductive coupling device also includes a sealing assembly forming a sealed space with the dielectric window to house the radio frequency coil within the sealed space. The sealing assembly has an inlet channel and an exhaust channel. The inlet channel is connected to a protective gas source to fill the sealed space with protective gas, and the exhaust channel is connected to an exhaust assembly to extract gas from the sealed space. The protective gas does not react with the silver layer to prevent corrosion of the silver layer.

[0006] Furthermore, the gas flow rate of the air intake channel and the air extraction channel is controlled to ensure that the gas pressure in the sealed space is not lower than the process gas pressure in the process chamber and not lower than 100 Torr.

[0007] Furthermore, the inductive coupling device also includes a pressure sensor, which is connected to the control device and used to detect pressure sensing information within the sealed space. The control device controls the gas flow rate of the air intake channel and / or the air extraction channel based on the pressure sensing information.

[0008] Furthermore, the inductive coupling device also includes a temperature sensor, which is connected to the control device and used to detect the temperature sensing information of the radio frequency coil; when the radio frequency coil is energized, the control device controls the gas flow rate of the air intake channel and / or the air extraction channel according to the temperature sensing information, so as to keep the temperature of the radio frequency coil within the target temperature range.

[0009] Furthermore, a first solenoid valve is provided between the air intake channel and the protective gas source, and a second solenoid valve is provided between the air extraction channel and the air extraction assembly; And / or, a mass flow controller is provided between the air intake channel and the protective gas source.

[0010] Furthermore, when the radio frequency coil is energized, the protective gas source and the vacuum assembly remain open; when the radio frequency coil is not energized, the protective gas source and the vacuum assembly are open for a period of time and then closed until the sealed space is filled with protective gas. And / or, the protective gas is an inert gas, which includes one of nitrogen, helium, and argon; And / or, the air pressure within the sealed space is controlled to be no higher than 770 Torr.

[0011] Furthermore, the sealing assembly is provided with a plurality of air intake channels, which are evenly distributed around the radio frequency coil.

[0012] Furthermore, the air intake direction of each of the air intake channels is aligned with the central axis of the medium window or is tangent to the outer peripheral surface of the medium window.

[0013] Furthermore, the air intake channel and the air extraction channel are respectively located on opposite sides of the sealed space.

[0014] A second aspect of the present invention provides a plasma device, including a process chamber and an inductive coupling device for coupling radio frequency energy into the process chamber through a dielectric window of the process chamber, wherein the inductive coupling device is an inductive coupling device as described above.

[0015] By adopting the above technical solution, the present invention has the following advantages over the prior art: This invention recognizes that one of the fundamental reasons for the decline in plasma density, stability, and uniformity in existing technologies is the irreversible sulfidation and oxidation corrosion of the silver plating layer of the radio frequency (RF) coil due to long-term exposure to air. Based on this, this invention constructs a sealed space surrounding the RF coil. By introducing and expelling protective gas into the sealed space, the RF coil is completely enclosed in a protective gas environment, preventing the silver plating layer from being exposed to the atmosphere. This inhibits sulfidation and oxidation of the silver plating layer, ensuring efficient and stable coupling of RF energy into the process chamber. This allows the plasma density to be stably maintained at its initial high level during long-term operation. Simultaneously, it avoids the problem of uneven plasma density distribution caused by non-uniform corrosion of the silver plating layer, which leads to distortion of the electromagnetic field generated by the coil. Furthermore, the flowing protective gas helps to remove the heat generated by the RF coil during operation, acting as an active cooling mechanism. Therefore, there is no need for an additional fan, eliminating the problem of electromagnetic field disturbances and instantaneous plasma fluctuations caused by vibrations during fan cooling, further enhancing the overall stability and repeatability of the plasma generation process. In addition, this invention has a simple and compact structure, lower modification costs compared to existing technologies, and is easy to implement. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of a conventional plasma device. Figure 2 This is a schematic diagram of one embodiment of the plasma device in this invention; Figure 3 This is a schematic diagram of another embodiment of the plasma device in this invention. Detailed Implementation

[0017] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0018] It should be noted that the illustrations provided in the embodiments are only schematic representations of the basic concept of the present invention. Although the illustrations only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation, the shape, quantity, positional relationship and proportion of each component in the actual implementation can be changed at will under the premise of realizing the technical solution of the present invention, and the layout of the components may also be more complex.

[0019] like Figure 1As shown, existing plasma devices typically include a process chamber 20 and an inductive coupling device for coupling radio frequency energy into the process chamber 20 through a dielectric window 21.

[0020] The process chamber 20 is connected to a vacuum device (not shown) via a vacuum channel 22 to evacuate the process chamber 20. A stage 23 for carrying the workpiece 10 to be processed (e.g., a wafer) is disposed inside the process chamber 20 and is connected to the lower electrode RF power supply 24 as the lower electrode. The top of the process chamber 20 is provided with a top plate 25, which includes a central region and an extension 251 surrounding the central region. The central region is provided with an air inlet structure 252, through which process gas can enter the process chamber 20. The dielectric window 21 is cylindrical, with its top sealed to the bottom surface of the central region of the top plate 25 and its bottom sealed to the inner ring of the annular cover plate 26 of the process chamber 20.

[0021] The core of the inductive coupling device is the RF coil 31 outside the dielectric window 21. The RF coil 31 is connected to the upper RF power supply 32 via a matching unit (not shown) to excite and maintain plasma within the process chamber 20. When the RF coil is energized, due to the "skin effect" of the high-frequency RF current, the current will concentrate on the surface of the coil conductor. Therefore, the key to RF transmission lies in the surface of the coil. In order to improve conductivity, reduce RF loss and reduce cost, the RF coil 31 is usually made of ordinary copper and its surface is silver-plated to form a silver plating layer.

[0022] In addition, the inductive coupling device also includes a protective cover 33 mounted on an annular cover 26 of the process chamber 20. This protective cover 33 is located outside the dielectric window 21 and forms a protective space with the dielectric window 21 to protect the RF coil 31 within that space. Figure 1 In the device shown, the annular cover 26 seals the bottom of the protective space, and the extension 251 of the top plate 25 (which is disposed opposite to the annular cover 26) forms the top of the protective space. Since the radio frequency coil 31 generates heat during operation and needs to be dissipated, a fan 34 is also provided at the top of the protective space (i.e., the bottom surface of the extension 251). At the same time, through holes are provided on both the extension 251 and the protective cover 33 to allow the fan to generate airflow to remove the heat from the coil.

[0023] However, the inventors noted that after the above-mentioned equipment has been used for a period of time, the stability and uniformity of plasma distribution tend to decrease, and the plasma density tends to decrease even when the process conditions such as RF power supply and process gas remain unchanged.

[0024] Through extensive research, the inventors realized that one of the root causes of the above problems is that, in the aforementioned equipment, because air circulates within the protected space, the silver plating layer on the surface of the radio frequency coil 31 is constantly exposed to the air. This exposure results in a reaction with the combined effects of sulfides (such as hydrogen sulfide and sulfur dioxide), oxygen, and water vapor, generating compounds with high resistivity. Furthermore, due to the "skin effect" of high-frequency radio frequency current, the current concentrates on the surface of the coil. In other words, radio frequency transmission depends on the integrity of the silver plating layer on the coil surface. Once the silver plating layer is corroded, generating sulfides or oxides with even higher resistivity, the following problems will directly occur: (1) Decreased radio frequency energy transmission efficiency (most direct impact) High-frequency radio frequency (RF) current exhibits a "skin effect," meaning the current primarily flows on the surface of the coil. The resistivity of silver sulfide or silver oxide, formed by the corrosion of the silver plating, is much higher than that of pure silver. Therefore, the effective conductivity of the coil surface decreases sharply after corrosion. Consequently, a significant amount of RF power is lost as heat in the coil, rather than being effectively coupled into the process chamber for plasma excitation and maintenance. This directly manifests as reduced RF utilization, requiring higher power input to achieve the original plasma density.

[0025] (2) Decreased plasma density and stability The density and excitation efficiency of the plasma directly depend on the radio frequency energy coupled into the chamber. Due to the decrease in radio frequency energy transmission efficiency, the energy available for ionizing the process gas is reduced. Consequently, the generated plasma density decreases, leading to slower etching or deposition rates, longer process times, and reduced throughput. Furthermore, unstable energy coupling results in plasma instability, making the process uncontrollable and reducing repeatability.

[0026] (3) Process uniformity deteriorates The electromagnetic field distribution generated by the inductively coupled coil determines the uniformity of plasma spatial distribution within the cavity. However, the corrosion of the silver plating layer is often uneven, with areas of severe localized corrosion exhibiting higher resistance, resulting in weakened or distorted magnetic field strength in those areas. This leads to uneven electromagnetic field distribution within the cavity, consequently causing uneven plasma density distribution. On the wafer, this directly manifests as uneven etching or deposition thickness / rate, deterioration of on-wafer uniformity (WIWNU) indicators, and decreased product yield.

[0027] (4) Loss of process repeatability and consistency Semiconductor manufacturing demands extremely high run-to-run consistency in process results, but the etching of silver plating is a process that deteriorates continuously over time. This causes process parameters (such as rate and uniformity) to drift, making it impossible to maintain batch-to-batch consistency. This makes process windows difficult to control, requiring frequent equipment calibration and process verification, increasing maintenance costs and downtime.

[0028] (5) Reduced equipment reliability and increased maintenance costs Additional power loss causes the coil temperature to rise abnormally, which may accelerate the aging of other components (such as dielectric windows and sealing materials). At the same time, the changing coil impedance will put pressure on the RF matching network, causing the matching unit to be adjusted frequently or even fail, reducing system stability.

[0029] Furthermore, the use of fans for cooling generates vibrations, which are transmitted to the RF coils and dielectric windows, causing minute displacements or deformations. This results in slight changes in the coil's position relative to the dielectric window and process chamber, directly altering the spatial distribution of the generated electromagnetic field. Since plasma generation and maintenance are highly dependent on this electromagnetic field, instantaneous disturbances in the field distribution lead to synchronous, high-frequency fluctuations and localized inhomogeneities in the plasma density, further affecting the stability and uniformity of plasma generation.

[0030] To prevent the RF coil from being oxidized or sulfided, the inventors first thought of replacing the silver plating on the surface of the RF coil 31 with a more corrosion-resistant plating (such as a gold plating). However, this would greatly increase the cost and would still not completely eliminate the potential degradation in long-term complex environments, nor would it avoid the impact of fan vibration.

[0031] The inventors discovered that providing a protective gas environment for the radio frequency coil 31 can prevent its silver plating layer from reacting with sulfides, oxygen, water vapor, etc., in the air. Therefore, this invention overturns the existing coil protection approach by constructing a dynamic sealed space 30 around the radio frequency coil 31 on the plasma device, equipped with an intake channel and an exhaust channel. Protective gas is continuously injected into the sealed space 30 through the intake channel, while gas is simultaneously extracted through the exhaust channel, thus replacing the internal air environment with a protective gas environment that is less likely to react with the silver plating layer. In this environment, because the silver plating layer loses the conditions for oxidation and sulfidation and does not react with the protective gas, corrosion is inhibited at its source, thereby ensuring high efficiency of radio frequency transmission and long-term stability of the equipment.

[0032] Most importantly, because the flowing protective gas itself has cooling properties, it can efficiently remove the heat generated when the RF coil 31 is energized while providing protection. This means that the present invention eliminates the need for fans in existing equipment to dissipate heat from the coil, thus completely abandoning the traditional solution that required the introduction of a corrosive medium (air) for heat dissipation. In other words, the flowing protective gas in the present invention simultaneously undertakes the dual tasks of isolating air and dissipating heat, perfectly resolving the inherent contradiction in traditional solutions where the cooling medium (i.e., air) itself is a source of corrosion. At the same time, omitting the fan avoids the adverse effects of mechanical vibration on the plasma, achieving two goals at once.

[0033] As can be seen, this invention achieves reliable protection of the silver plating layer through a disruptive design of "environmental reconstruction" and "functional integration," and avoids the impact of fan vibration, thereby solving the problems of decreased plasma density, deteriorated uniformity, and reduced process stability. Furthermore, it has lower modification costs compared to existing plasma equipment, requires no changes to the core coil and chamber design, and is easy to implement.

[0034] It should be noted that, in implementing the above-mentioned technical concept, this invention also innovatively proposes the following design: Firstly, the gas pressure within the sealed space is controlled to be no lower than the process gas pressure of the process chamber 20. This ensures that even if there is a minor leak between the chamber and the sealed space, the airflow direction will always be from the sealed space to the process chamber 20, thereby preventing plasma leakage from the chamber and forming a reliable one-way protective barrier. As is well known, plasma leakage into the sealed chamber will pose a safety hazard, and when the gas pressure within the sealed space is lower than the process gas pressure of the process chamber 20, it will be difficult to detect leaks in the process chamber 20. Simultaneously, the gas pressure within the sealed space should be controlled to be no lower than 100 Torr to prevent the energy of the RF coil from ionizing the protective gas within the sealed space.

[0035] Secondly, this invention designs a dynamic pressure closed-loop control system. By linking a pressure sensor with the control device, the intake and exhaust rates of the protective gas are adjusted in real time, ensuring that the gas pressure within the sealed space 30 remains within the required target pressure range. The lower limit of the target pressure range is referenced in the first aspect, while the upper limit is controlled within 770 Torr (i.e., 1 atmosphere + 10 Torr). This ensures sufficient positive pressure protection while avoiding excessive mechanical load on the inner wall of the sealed space 30 and preventing challenges to its sealing performance.

[0036] Thirdly, for different scenarios where the RF coil 31 is energized and not energized, the flow field in the sealed space 30 is intelligently controlled: when the coil is energized, the aforementioned dynamic pressure closed-loop control mode is adopted to continuously introduce and discharge protective gas to achieve protection and cooling functions; when the coil is not energized, there is no need for cooling, so the protective gas source and the air extraction component are controlled to run for a period of time and then shut off, so that the air in the sealed space 30 is completely discharged and kept full of protective gas, so as to maintain the protective gas environment with minimal consumption.

[0037] Fourthly, multiple air intake channels are arranged around the RF coil 31 to ensure that the protective gas flows through the sealed space 30 without any dead angles. The air intake direction of each channel can be set to align with the central axis of the dielectric window 21, thereby forming an impinging jet that can quickly remove the heat generated by the RF coil 31. Furthermore, the air intake direction of each channel can also be set to be tangent to the outer peripheral surface of the dielectric window 21. This design guides the airflow to rotate and flow near the outer surface of the dielectric window 21. This swirling flow can form a relatively stable and continuously renewed protective gas "sheath" on the coil surface, optimizing the uniformity of protection and heat dissipation.

[0038] In summary, the core of this invention lies in constructing a dynamically controllable protective gas environment, supplemented by precise gas pressure control, optimized flow field design, and intelligent operating logic, thereby achieving a comprehensive improvement in equipment reliability and process stability.

[0039] Based on the above inventive concept, the inductive coupling device and plasma equipment provided by the present invention will be described exemplarily below.

[0040] Example 1 This embodiment provides an inductive coupling device for coupling radio frequency energy into the process chamber 20 through a dielectric window 21. For example... Figure 2 and Figure 3 As shown, the inductive coupling device mainly includes a radio frequency coil 31 disposed outside the dielectric window 21. The radio frequency coil 31 is connected to the upper-stage radio frequency power supply 32 via a matching unit (not shown) to excite and maintain plasma within the process chamber 20. The main body of the radio frequency coil 31 is preferably made of copper. To improve conductivity under the "skin effect" of high-frequency radio frequency current, a silver plating treatment is performed on the surface of the copper coil to form a silver plating layer.

[0041] To suppress the sulfidation and oxidation of the silver plating layer of the coil in air, the inductive coupling device of this embodiment further includes a sealing assembly, which forms a sealed space 30 with the dielectric window 21 to house the radio frequency coil 31 within the sealed space 30. The sealing assembly is provided with an air inlet channel 36 and an air extraction channel 37. The air inlet channel 36 is connected to a protective gas source (not shown) to fill the sealed space 30 with protective gas provided by the protective gas source; the air extraction channel 37 is connected to an air extraction assembly 38 to extract gas from the sealed space 30.

[0042] Therefore, by forming a sealed space 30 that completely encloses the RF coil 31, and by equipping it with an air intake channel 36 connected to a protective gas source and an air extraction channel 37 connected to an air extraction assembly 38, the air within the sealed space 30 is dynamically replaced with a protective gas, thus completely suppressing the oxidation and sulfidation reactions of the silver plating layer at the source. Furthermore, the flowing protective gas, while providing protection, also efficiently removes the heat generated by the RF coil 31 during operation, achieving active cooling of the coil. This replaces the contradictory solution of using a traditional fan to introduce corrosive air for heat dissipation, solving the heat dissipation requirement while protecting the coil.

[0043] In this embodiment, the protective gas is a gas that does not react with the silver plating layer to prevent the silver plating layer from being corroded. Specifically, one of the inert gases such as nitrogen, helium, and argon can be used. Considering cost and safety, nitrogen is the best choice.

[0044] exist Figure 2 In the illustrated implementation, by Figure 1 A sealing cover 35, covering the top plate 25 and the protective cover 33, is fixedly mounted on the annular cover 26 of the process chamber 20 as the aforementioned sealing assembly. The bottom of the sealing cover is sealed by the annular cover 26, and the extension 251 of the top plate 25 has a through hole, allowing gas to flow within the interior of the sealing cover (i.e., the sealed space 30 enclosed by the annular cover 26, the medium window 21, the central area of ​​the top plate 25, and the sealing cover 35). See again... Figure 2 As shown, the air intake channel 36 passes through the sealing cover 35 and the protective cover 33 in sequence to introduce protective gas into the sealed space 30. The air extraction assembly 38 extracts the gas outward through the air intake channel 36 passing through the sealing cover 35 and then delivers it to the exhaust gas treatment device (not shown) for treatment.

[0045] exist Figure 3 In another embodiment shown, by... Figure 1 The top plate 25 and protective cover 33 of the process chamber 20 shown are formed as a sealed structure to serve as the aforementioned sealing assembly, thus eliminating the need for an additional sealing cover 35. In this case, the aforementioned protective space is formed as a sealed space 30.

[0046] In this embodiment, a pressure sensor (not shown) is also provided in the sealed space 30. The pressure sensor is connected to a control device (not shown) to implement dynamic air pressure closed-loop control of the sealed space 30 when the radio frequency coil 31 is working.

[0047] Specifically, when the radio frequency coil 31 is energized, the control device controls both the protective gas source and the extraction assembly to open, and controls the gas flow rate of the intake channel 36 and / or the extraction channel 37 based on the pressure sensing information collected by the pressure sensor, so as to maintain the gas pressure in the sealed space 30 within the target gas pressure range. The lower limit of the target gas pressure range is not lower than the process gas pressure in the process chamber 20 and not lower than 100 Torr, and the upper limit of the target gas pressure range is not higher than the difference between the target gas pressure range and atmospheric pressure, i.e., not higher than 770 Torr. For example, the sealed space 30 can be maintained at gas pressures of 100 Torr, 200 Torr, 300 Torr, 400 Torr, 500 Torr, 600 Torr, 700 Torr, 770 Torr, etc. Preferably, the target gas pressure range is 760 Torr ± 10 Torr.

[0048] Thus, by dynamically balancing the intake and exhaust, a stable and moderate positive pressure environment is maintained, which effectively prevents plasma leakage from the process chamber 20 due to excessively low air pressure, avoids excessive pressure on the walls of the sealed space 30 due to excessively high air pressure and leakage of protective gas, and also prevents the radio frequency coil 31 from ionizing the inert gas in the sealed space 30.

[0049] In addition, the inductive coupling device may also include a temperature sensor (not shown), which is also connected to the control device and is used to detect the temperature sensing information of the radio frequency coil 31. When the radio frequency coil 31 is energized, the control device can control the gas flow rate of the air intake channel 36 and / or the air extraction channel 37 according to the temperature sensing information, so as to keep the temperature of the radio frequency coil 31 within the target temperature range.

[0050] In addition, the control device can also combine the aforementioned temperature sensing information and pressure sensing information to control the gas flow rate of the air intake channel 36 and / or the air extraction channel 37, so that the air pressure in the sealed space 30 is kept within the target air pressure range and the temperature of the radio frequency coil 31 is kept within the target temperature range, thereby achieving the optimal flow rate distribution for on-demand cooling and on-demand protection. While ensuring that the air pressure meets the requirements, it can also effectively prevent the radio frequency coil 31 from overheating.

[0051] Preferably, the temperature sensor is a non-contact sensor, such as an infrared sensor, to avoid coupling between the sensor body and the radio frequency coil 31, which would interfere with the transmission of radio frequency energy.

[0052] In one embodiment, a first solenoid valve 361 is provided between the air intake channel 36 and the protective gas source, and a second solenoid valve 371 is provided between the air extraction channel 37 and the air extraction assembly 38. A control device is connected to the first solenoid valve 361 and the second solenoid valve 371 respectively to control the opening and closing of the air intake channel 36 and the air extraction channel 37. The gas flow rate in the air intake channel 36 can be controlled by adjusting the opening of the first solenoid valve 361, and the gas flow rate in the air extraction channel 37 can be controlled by adjusting the opening of the second solenoid valve 371. As an electrically controllable and rapidly adjustable component, the solenoid valve provides favorable conditions for dynamic air pressure closed-loop control.

[0053] In another embodiment, a mass flow controller (not shown) can also be installed between the air intake channel 36 and the protective gas source. The mass flow controller can directly measure and control the mass flow of the gas. Compared with the solenoid valve that only adjusts the valve opening, it has the advantages of high control accuracy, fast response speed and good stability. Using a mass flow controller can maintain the gas pressure and gas replacement speed in the sealed space 30 more accurately and stably.

[0054] In this embodiment, when the radio frequency coil 31 is not energized, since the radio frequency coil 31 does not require heat dissipation, the control device can control the protective gas source and the air extraction component to be turned on for a period of time and then turned off, so that the sealed space 30 is kept full of protective gas and the gas pressure is maintained within 760 Torr ± 10 Torr, thereby effectively protecting the silver plating layer from corrosion while greatly reducing the consumption of protective gas.

[0055] In this embodiment, the sealing assembly is provided with multiple air intake channels 36, which are evenly distributed around the radio frequency coil 31 to eliminate dead airflow angles in the sealing space 30 and avoid insufficient local protection or uneven cooling of the coil due to uneven distribution of protective gas.

[0056] In this embodiment, the dielectric window 21 is cylindrical, and the radio frequency coil 31 is a three-dimensional coil surrounding the dielectric window 21. The air intake direction of each air intake channel 36 can be aligned radially with the central axis of the dielectric window 21 or tangent to the outer peripheral surface of the dielectric window 21. When the air intake direction is aligned with the central axis of the dielectric window 21, an impinging jet can be formed, which can quickly remove the heat generated by the radio frequency coil 31. When the air intake direction is tangent to the outer peripheral surface of the dielectric window 21, the airflow can be guided to rotate and flow near the outer surface of the dielectric window 21. This swirling flow can form a relatively stable and continuously renewed protective gas protection on the coil surface, optimizing the uniformity of protection and the heat dissipation effect.

[0057] In this embodiment, the air inlet channel 36 and the air extraction channel 37 are respectively located on opposite sides of the sealed space 30. For example, the air inlet channel 36 is located at the bottom of the sealed space 30, and the air extraction channel is located at the top of the sealed space 30; or conversely, the air inlet channel 36 is located at the top of the sealed space 30, and the air extraction channel 37 is located at the bottom of the sealed space 30. This ensures that the protective gas, after entering from one end, flows through almost the entire sealed space 30 before being extracted from the other end. This maximizes the contact path and time between the gas and the coil, significantly improving the overall coverage efficiency and heat dissipation performance of the protective gas on the coil surface, while avoiding waste caused by gas flowing out directly before reaching the coil area.

[0058] It should be noted that although this embodiment only illustrates the case of the radio frequency coil 31 as a three-dimensional coil, it should be understood that the present invention is also applicable to plasma devices where the radio frequency coil 31 is planar. When the radio frequency coil 31 is a planar coil, it can be placed directly on the outer surface (usually the top surface) of the dielectric window 21, and the sealing assembly is configured to cover the outer side of the dielectric window and form a sealed space with the dielectric window 21.

[0059] Example 2 This embodiment provides a plasma device, including a process chamber 20 and an inductive coupling device for coupling radio frequency energy into the process chamber 20 through a dielectric window 21, wherein the inductive coupling device is the inductive coupling device provided in Embodiment 1.

[0060] like Figure 2 and Figure 3 As shown, in this embodiment, the process chamber 20 is connected to a vacuum device (such as a vacuum pump) via a vacuum channel 22 to evacuate the process chamber 20; the stage 23 is disposed inside the process chamber 20 to support the workpiece 10 to be processed, and is connected to the lower electrode RF power supply 24 as the lower electrode; the top of the process chamber 20 is provided with a top plate 25, which includes a central region and an extension 251 surrounding the central region, and the central region is provided with an air intake structure 252, through which process gas can enter the interior of the process chamber 20.

[0061] During the process, the upper-stage RF power supply provides RF current to the RF coil 31 through the matching unit. The RF current generates an alternating electromagnetic field under the action of the RF coil 31. This alternating electromagnetic field penetrates the dielectric window 21 and ionizes the process gas delivered to the process chamber 20 by the gas inlet structure 252.

[0062] When the inductive coupling device of Example 1 is used, the air in the sealed space can be dynamically replaced with protective gas by introducing and extracting protective gas, which completely suppresses the oxidation and sulfidation reaction of the silver plating layer from the source. In addition, the flowing protective gas can efficiently remove the heat generated by the radio frequency coil 31 during operation while playing a protective role, thus realizing active cooling of the coil and eliminating the need for an additional fan.

[0063] It should be noted that the plasma equipment in this embodiment may be, for example, a plasma etching equipment, a plasma resist stripping equipment, or a plasma deposition equipment, and this embodiment does not impose any specific limitations on it.

[0064] While specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of the present invention is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but all such changes and modifications fall within the scope of protection of the present invention.

Claims

1. An inductively coupled device for coupling radio frequency energy through a dielectric window into a process chamber to ionize a process gas within the process chamber into a plasma, wherein, The inductive coupling device comprises a radio frequency coil arranged outside the dielectric window, and a silver-plated layer is arranged on the surface of the radio frequency coil, characterized in that the inductive coupling device further comprises a sealing assembly, a sealed space is formed between the sealing assembly and the dielectric window, the radio frequency coil is arranged in the sealed space, and the sealing assembly is provided with an air inlet channel and an air outlet channel, the air inlet channel is communicated with a protective gas source to fill the sealed space with protective gas, and the air outlet channel is communicated with an air exhaust assembly to exhaust the gas in the sealed space, wherein the protective gas does not react with the silver-plated layer to prevent the silver-plated layer from being corroded.

2. The inductively coupled device of claim 1, wherein, The gas flow rates of the air inlet channel and the air outlet channel are controlled to ensure that the air pressure in the sealed space is not lower than the process air pressure in the process chamber and is not lower than 100 Torr.

3. The inductively coupled device of claim 2, wherein, The inductive coupling device further comprises a pressure sensor connected to a control device and used to detect pressure sensing information in the sealed space, and the control device controls the gas flow rates of the air inlet channel and / or the air outlet channel according to the pressure sensing information.

4. The inductively coupled device of claim 1, wherein, The inductive coupling device further comprises a temperature sensor connected to a control device and used to detect temperature sensing information of the radio frequency coil, and when the radio frequency coil is powered on, the control device controls the gas flow rates of the air inlet channel and / or the air outlet channel according to the temperature sensing information to keep the temperature of the radio frequency coil within a target temperature range.

5. The inductively coupled device of any one of claims 1-4, wherein, A first electromagnetic valve is arranged between the air inlet channel and the protective gas source, and a second electromagnetic valve is arranged between the air outlet channel and the air exhaust assembly. And / or, a mass flow controller is arranged between the air inlet channel and the protective gas source.

6. The inductively coupled device of claim 1, wherein, When the radio frequency coil is powered on, the protective gas source and the air exhaust assembly are continuously opened; when the radio frequency coil is not powered on, the protective gas source and the air exhaust assembly are opened for a period of time and then closed until the sealed space is filled with protective gas. And / or, the protective gas is inert gas, and the inert gas includes one of nitrogen, helium and argon. And / or, the air pressure in the sealed space is controlled to be not higher than 770 Torr.

7. The inductively coupled device of claim 1, wherein, A plurality of air inlet channels are arranged on the sealing assembly, and the plurality of air inlet channels are uniformly distributed around the radio frequency coil.

8. The inductively coupled device of claim 7, wherein, The air inlet direction of each air inlet channel is aligned with the central axis of the dielectric window or is tangent to the outer peripheral surface of the dielectric window.

9. The inductively coupled device of claim 1, wherein, The air inlet channel and the air outlet channel are arranged on opposite sides of the sealed space, respectively.

10. A plasma apparatus comprising a process chamber and an inductive coupling device for coupling radio frequency energy through a dielectric window of the process chamber into the process chamber, characterized in that, The inductive coupling device adopts the inductive coupling device according to any one of claims 1 to 9.

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