Hollow cathode enhanced remote plasma photoresist removal apparatus and method

Abstract

The present application relates to photoresist removal technical field, especially in kind of hollow cathode enhanced remote plasma photoresist removal device and method, the device includes vacuum reaction cavity, and it is divided into upstream discharge area, diffusion mixing area and downstream glue removal reaction area in proper order in it;Hollow cathode remote plasma source is arranged in upstream discharge area, and the hollow cathode discharge space is formed by porous lower electrode plate and upper electrode plate;Gas homogenization structure is arranged in diffusion mixing area;Wafer stage and pumping module are arranged in downstream glue removal reaction area.The present application utilizes hollow cathode effect to generate high-density neutral active groups in upstream, and after high-energy particles are blocked by gas homogenization structure and are uniformly distributed, the neutral active groups enter downstream reaction area, wafer stage only applies low-power bias or does not apply bias, to realize photoresist removal mainly by neutral group chemical reaction.The problems of traditional remote plasma glue removal, such as insufficient activity, poor uniformity and easy damage to wafer, are effectively solved.

Description

Technical Field

[0001] This invention relates to the field of photoresist removal technology, and in particular to a hollow cathode enhanced remote plasma photoresist removal apparatus and method. Background Technology

[0002] Currently, photoresist removal is a critical process in semiconductor manufacturing and advanced packaging. The mainstream technologies include wet photoresist removal, in-situ plasma photoresist removal, and remote plasma photoresist removal. Wet photoresist removal relies on organic solvents or strong oxidizing solutions to peel and dissolve the photoresist. Although the process is mature, it suffers from high chemical consumption and expensive waste disposal. Furthermore, when dealing with high aspect ratio structures, the solution struggles to fully wet the bottom of the trenches, easily leading to incomplete removal of residues within narrow structures, thus limiting its application in advanced process nodes.

[0003] In-situ plasma resist removal achieves a high resist removal rate by directly exciting plasma in a cavity space near the wafer and utilizing the synergistic effect of high-energy ions and active groups. However, because the plasma discharge region is close to the wafer surface, the intense bombardment of high-energy ions, strong ultraviolet radiation, and the resulting surface charging effect can easily cause irreversible physical damage to low-k dielectric materials, fine metal interconnect layers, and various sensitive films, making it difficult to meet the stringent requirements of high-precision devices for low-damage processes.

[0004] To address the aforementioned issues, remote plasma resist removal technology has emerged. Its core idea is to spatially separate the plasma discharge region from the wafer reaction region. Reference document CN120511203A, "A Remote Plasma Resist Removal Uniformity Measurement System and Method Thereof," also mentions that a spray disk structure isolates the discharge domain from the resist removal reaction domain, ensuring that the particles reaching the wafer surface are primarily chemically active neutral groups, thereby effectively reducing the risk of damage from ion bombardment.

[0005] Despite the significant advantages of remote plasma resist removal in terms of low damage, traditional methods still face the fundamental bottleneck of limited active particle generation efficiency. Because active groups are prone to recombination or adsorption and attenuation by the cavity walls as they pass through the spray plate or long-distance transport channel, the effective density of reactive particles reaching the wafer surface is insufficient. This leads to poor radial uniformity of the reaction cavity and lower removal rates for thick resists or highly cross-linked carbonized resists at low temperatures.

[0006] Hollow cathode discharge (also known as Schuler discharge), as a special form of glow discharge, can significantly enhance the collision frequency between electrons and gas due to its unique "trapping effect," thereby improving the gas ionization rate. Reference document CN119392187A discloses "An integrated device for vacuum diffusion plating with a hollow cathode-assisted active screen and its application method," which utilizes a hollow cathode system composed of a porous plate and a solid plate to successfully enhance plasma discharge and improve spatial distribution. However, this technology is mainly aimed at the field of metal surface diffusion plating. Its working gas environment, high-temperature process requirements, and structural arrangement differ significantly from the low-temperature, clean, and extremely low-damage requirements for semiconductor photoresist removal, making it unsuitable for direct application.

[0007] Furthermore, while some existing technologies attempt to apply hollow cathodes or remote plasmas independently to semiconductor processing, an effective synergistic mechanism has yet to be established. For example, the "plasma processing device" disclosed in CN122095455A places the hollow cathode near the workpiece, which is essentially still an in-situ processing mode and fails to construct a remote active particle enhancement source. Patents such as CN121869785A, CN122094408A, and CN122094433A focus on pipeline cleaning, patterned assistance, or wet cleaning, respectively, and none of them involve a technical solution that uses a hollow cathode as a remote source to enhance the active particles for adhesive removal and combines it with spray plate homogenization and downstream low-energy bias for synergistic design.

[0008] Therefore, there is an urgent need for a new type of desizing device and method that can achieve high desizing rate, excellent uniformity and extremely low wafer damage. Summary of the Invention

[0009] In order to address the technical deficiencies mentioned in the background art, the present invention aims to provide a hollow cathode enhanced remote plasma photoresist removal apparatus and method to solve the above problems.

[0010] To achieve the above objectives, the present invention adopts the following technical solution: A hollow cathode enhanced remote plasma photoresist removal device includes: The vacuum reaction chamber is divided into an upstream discharge zone, a diffusion mixing zone, and a downstream debinding reaction zone along the gas flow direction. A hollow cathode remote plasma source is disposed in the upstream discharge region and includes at least one set of hollow cathode units; the hollow cathode unit includes an upper electrode plate and a lower electrode plate that are insulated from each other, a hollow cathode discharge space is formed between the upper electrode plate and the lower electrode plate, and a plurality of cathode holes are provided on the lower electrode plate; The gas supply module is connected to the upstream discharge region and is used to supply process gas to the hollow cathode remote plasma source; A gas homogenization structure is disposed in the diffusion mixing region to uniformly distribute the neutral active groups generated in the upstream discharge region to the downstream desizing reaction region and to block high-energy electrons, ions and ultraviolet radiation from directly reaching the wafer surface. A wafer stage, located in the downstream resist removal reaction zone, is used to support and heat or cool the wafer; The air extraction module is connected to the downstream degumming reaction zone and is used to maintain the process pressure inside the chamber and discharge the reaction products.

[0011] Specifically, the gas supply module includes: A gas pipeline, connected to the upstream discharge region, is used to supply process gas to the hollow cathode remote plasma source; A mass flow controller is installed in the gas pipeline to control the mass flow rate through the gas pipeline; A valve is installed in the gas pipeline to control the opening and closing of the gas pipeline; The process gas is one or more of the following: O2, N2, Ar, H2, and CF4.

[0012] Specifically, the air extraction module includes: The exhaust pipe is connected to the downstream degumming reaction zone; A pressure control valve, installed in the exhaust pipe, is used to control the process pressure in the downstream degumming reaction zone; A vacuum pump, connected to the exhaust pipe, is used to remove reaction byproducts from the downstream degumming reaction zone.

[0013] Specifically, the gas homogenization structure is a spray plate or an active screen. Specifically, the spray plate is a single-layer perforated plate or a double-layer staggered perforated plate.

[0014] Specifically, the active screen has a ring-shaped porous structure.

[0015] Specifically, the diameter of the cathode hole is 0.5–10 mm, and the depth-to-diameter ratio is 1–20; The distance between the upper electrode plate and the lower electrode plate is 0.5–20 mm.

[0016] Specifically, the wafer stage is equipped with heating channels and cooling channels, and the temperature controllable range of the wafer stage is 50–300℃.

[0017] Specifically, it also includes a power module, which comprises: A discharge power supply is used to drive the hollow cathode remote plasma source; A bias power supply is used to apply an radio frequency or pulse bias voltage to the wafer stage.

[0018] Specifically, the discharge power supply is a DC power supply, a pulsed DC power supply, or a radio frequency power supply; The bias power supply has a frequency of 400kHz–13.56MHz and a bias power of 0–300W.

[0019] Specifically, the hollow cathode enhanced remote plasma photoresist removal device also includes a closed-loop control system for collecting the voltage, current or self-pulse signal of the hollow cathode discharge, and adjusting the discharge power, gas flow rate, chamber pressure and bias power in conjunction with the signal.

[0020] A method for removing photoresist includes the following steps: S1. Place the wafer to be processed on the wafer stage in the downstream resist removal reaction area, start the vacuum module, and pump the vacuum reaction chamber to the preset process pressure. S2. Process gas is introduced into the upstream discharge area through the gas supply module, and the hollow cathode remote plasma source is turned on, so that the gas forms high-density neutral active groups in the hollow cathode discharge space. S3. Neutral active groups are uniformly introduced into the downstream photoresist removal reaction zone through the gas homogenization structure, where they react chemically with the photoresist on the wafer surface to generate volatile products, which are then discharged by the gas extraction module. S4. Adjust the resist removal rate and uniformity by controlling the temperature of the wafer stage and / or using low power bias. S5. Based on the discharge status feedback signal, adjust the process parameters in a closed loop until the adhesive removal is completed.

[0021] Beneficial effects: This application significantly improves the efficiency of active group generation by setting a hollow cathode remote plasma source in the upstream discharge region and utilizing the electron reciprocating oscillation effect within the cathode aperture. Furthermore, a gas homogenization structure in the diffusion mixing region blocks high-energy electrons and ultraviolet radiation, ensuring that the downstream photoresist removal reaction region only uses neutral groups for chemical reactions. This approach achieves both high photoresist removal rate and low damage characteristics at the source. High-density particles are uniformly distributed using a spray disk or active screen, and combined with temperature control and low-power bias on the wafer stage, the problems of traditional remote plasma transmission attenuation and poor radial uniformity are effectively solved. In addition, by collecting the self-pulse signal of the hollow cathode discharge and adjusting the process parameters accordingly, the discharge state is controlled, significantly improving process stability and adaptability to different photoresist materials. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the hollow cathode enhanced remote plasma photoresist removal device of this application; Figure 2 The figure shows the normalized simulation results of the hollow cathode-enhanced remote debonding method in this application.

[0023] Reference numerals: Chassis 10, Storage base 11, Storage box 12, Divider tray 13, Cover 14, Motor 15, Bearing 16, Rotating shaft 17, Base plate 18, Casters 19, Emergency switch 110, Supporting mechanism 20, Support frame 21, Supporting assembly 22, First mounting post 221, First pin 222, Insertion part 223, Limiting assembly 23, Third mounting post 231, Contour block 232, Pressing assembly 24, Second mounting post 241, Telescopic actuator 242, Limiting seat 243, Clearance hole 2431, Pressing structure 244, Rotating seat 2441, Pressing arm 2442, Pressing head 2443, Connecting rod 2444, Reducer housing 30, Positioning hole 31, Intermediate hole 32, Mounting hole 33, Nut 34, Control display panel 40, Electric riveting tool 50, Safety monitoring mechanism 60, Transmitting grating 61, Receiving grating 62. Detailed Implementation

[0024] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0025] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0026] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature.

[0027] In this application, unless otherwise expressly specified and limited, the terms “installation,” “connection,” “linking,” “fixing,” etc., shall be interpreted broadly. For example, they may refer to a fixed connection, a detachable connection, or an integral part; they may refer to a mechanical connection or an electrical connection; they may refer to a direct connection or an indirect connection through an intermediate medium; they may refer to the internal connection of two components or the interaction between two components, unless otherwise expressly limited.

[0028] like Figure 1 As shown, this application discloses a hollow cathode enhanced remote plasma photoresist removal device, including a vacuum reaction chamber 10, a hollow cathode remote plasma source 20, a gas supply module 30, a gas homogenization structure 40, a wafer stage 50, and a gas extraction module 70.

[0029] The vacuum reaction chamber 10 is divided into an upstream discharge region 11, a diffusion mixing region 12, and a downstream resist removal reaction region 13 along the gas flow direction. This segmented structural design is the basis for achieving remote resist removal. The upstream discharge region 11 focuses on high-energy-density plasma excitation, while the downstream resist removal reaction region 13 focuses on the chemical reaction on the surface of the wafer 60. The two are separated by the diffusion mixing region 12, thereby physically blocking the direct bombardment of the wafer 60 by high-energy ions and ultraviolet radiation, ensuring low-damage characteristics of the process.

[0030] A hollow cathode remote plasma source 20 is disposed within the upstream discharge region 11 and includes at least one set of hollow cathode units 21. Each hollow cathode unit 21 includes an upper electrode plate 211 and a lower electrode plate 212, which are mutually insulated by insulating supports such as insulating pillars. A hollow cathode discharge space 201 is formed between the upper electrode plate 211 and the lower electrode plate 212, and the lower electrode plate 212 has multiple cathode holes 202. This structure utilizes the hollow cathode effect, causing electrons to be bound by an electric field and oscillate repeatedly within the cathode holes 202, greatly increasing the probability of collisions between electrons and process gases, thereby significantly improving the generation efficiency of active particles and solving the problem of insufficient activity in traditional remote sources.

[0031] The gas supply module 30 is connected to the upstream discharge region 11 and is used to supply process gas to the hollow cathode remote plasma source 20. The gas supply module 30 includes a gas pipeline 31, a mass flow controller 32, and a valve 33. The gas pipeline 31 is connected to the upstream discharge region 11 and serves as a channel for process gas transmission; the mass flow controller 32 is located in the gas pipeline 31 and is used to precisely control the mass flow rate of the gas flowing through the gas pipeline 31 to ensure the stability of the process gas ratio in the reaction chamber; the valve 33 is located in the gas pipeline 31 and is used to control the on / off state of the gas pipeline 31 to achieve safe control of process start-up and shutdown. The process gas uses one or more mixed gases selected from O2, N2, Ar, H2, and CF4, where O2 is used as the main oxidant, Ar is used as a buffer gas to maintain the discharge, and H2 or CF4 is used for auxiliary reactions for specific types of difficult-to-remove photoresists.

[0032] The vacuum module 70 is connected to the downstream degumming reaction zone 13 and is used to maintain the process pressure inside the chamber and discharge the reaction products. Specifically, the vacuum module 70 includes an exhaust pipe 71, a pressure control valve 72, and a vacuum pump 73. The exhaust pipe 71 is connected to the downstream degumming reaction zone 13, forming the outlet of the gas flow field; the pressure control valve 72 is located in the exhaust pipe 71 and precisely controls the process pressure of the downstream degumming reaction zone 13 by adjusting its opening degree. Different pressure environments correspond to different electron mean free paths, thereby affecting the generation and transport of active particles; the vacuum pump 73 is connected to the exhaust pipe 71 and is used to continuously remove reaction by-products (such as CO2, H2O, etc.) in the downstream degumming reaction zone 13 to prevent the accumulation of by-products from affecting the degumming rate.

[0033] A gas homogenization structure 40 is disposed within the diffusion mixing region 12 to uniformly distribute the neutral active groups generated in the upstream discharge region 11 to the downstream desizing reaction region 13, and to block high-energy electrons, ions, and ultraviolet radiation from directly reaching the surface of the wafer 60. The gas homogenization structure 40 is either a spray plate or an activation screen. The spray plate is preferably a single-layer porous plate or a double-layer staggered-hole plate. The double-layer staggered-hole design can further disrupt the high-speed jet upstream and enhance the diffusion effect. The activation screen is preferably an annular porous structure, suitable for large-area homogenization processing. This structure is not only a flow homogenizer but also a physical barrier, ensuring that only low-energy neutral groups can pass through, while high-energy particles are blocked upstream.

[0034] The aperture of the cathode hole 202 is 0.5-10 mm, and the depth-to-diameter ratio is 1-20; the distance between the upper electrode plate 211 and the lower electrode plate 212 is 0.5-20 mm. The above parameter range is the optimal range verified by a large number of experiments. If the aperture is too small, it will lead to poor ventilation and excessive pressure difference; if the aperture is too large, it will not be able to form an effective hollow cathode trapping effect. The matching of the plate spacing determines the electric field distribution of the discharge space and directly affects the intensity of electron oscillation.

[0035] A wafer stage 50 is located within the downstream resist stripping reaction zone 13 and is used to support and heat or cool the wafer 60. The wafer stage 50 has internal heating and cooling channels 51, and its temperature is controllable within a range of 50-300℃. Temperature control is a key variable in the resist stripping process. Appropriate heating (e.g., 150-250℃) can enhance the thermal motion of photoresist molecules and promote their chemical reaction rate with active groups, while the cooling channels 51 are used to prevent localized overheating that could damage low-k materials.

[0036] In addition, this application also includes a power supply module, which comprises a discharge power supply and a bias power supply. The discharge power supply is used to drive the hollow cathode remote plasma source 20, which can be a DC power supply, a pulsed DC power supply, or a radio frequency power supply. Different power supply modes are adapted to different process gases and pressure environments. The bias power supply is used to apply a radio frequency or pulsed bias voltage to the wafer stage 50. The frequency of the bias power supply is 400kHz-13.56MHz, and the bias power is 0-300W. The downstream low-power bias is only used to fine-tune the sheath voltage on the surface of the wafer 60, rather than relying on high-power ion bombardment as in in-situ resist removal, thereby controlling the ion energy below the damage threshold while ensuring the reaction rate.

[0037] This application also includes a closed-loop control system for acquiring voltage, current, or self-pulse signals of the hollow cathode discharge, and adjusting the discharge power, gas flow rate, chamber pressure, and bias power accordingly. This closed-loop mechanism can monitor minute changes in the discharge state in real time. For example, when an abnormal increase in discharge voltage is detected, the system can automatically increase the Ar gas ratio or reduce the power to prevent process drift and ensure a highly consistent processing environment for each wafer.

[0038] This application also discloses a method for removing photoresist, including the following steps: S1. Place the wafer 60 to be processed on the wafer stage 50 of the downstream resist removal reaction area 13, and start the vacuum module 70 to pump the vacuum reaction chamber 10 to the preset process pressure. S2. Process gas is introduced into the upstream discharge zone 11 through the gas supply module 30, and the hollow cathode remote plasma source 20 is turned on, so that the gas forms a high-density neutral active group in the hollow cathode discharge space 201. S3. Neutral active groups are uniformly introduced into the downstream photoresist removal reaction zone 13 through the gas homogenization structure 40, and react chemically with the photoresist on the surface of the wafer 60 to generate volatile products, which are then discharged by the gas extraction module 70. S4. Adjust the resist removal rate and uniformity by controlling the temperature of the wafer stage 50 and / or using low power bias. S5. Based on the discharge status feedback signal, adjust the process parameters in a closed loop until the adhesive removal is completed.

[0039] The core of this method lies in using the hollow cathode effect upstream to create high-density active ammunition, and then using downstream temperature control and low-voltage bias to guide the ammunition to accurately strike the photoresist. The whole process realizes the functional decoupling of the source region and the reaction region, which not only ensures sufficient reaction intensity, but also protects the microstructure integrity of the wafer 60 surface to the greatest extent.

[0040] The following four embodiments illustrate the hollow cathode enhanced remote plasma photoresist removal apparatus and photoresist removal method of this application: Example 1 This embodiment provides a hollow cathode enhanced remote plasma photoresist removal device, which is suitable for photoresist removal processes on conventional-sized wafers.

[0041] like Figure 1 As shown, the hollow cathode enhanced remote plasma photoresist removal apparatus includes a vacuum reaction chamber 10, which is divided into an upstream discharge region 11, a diffusion mixing region 12, and a downstream photoresist removal reaction region 13 along the airflow direction. A hollow cathode remote plasma source 20 is disposed within the upstream discharge region 11. The hollow cathode remote plasma source 20 includes a set of hollow cathode units 21, each consisting of a solid upper electrode plate 211 and a porous lower electrode plate 212. These two units are isolated by an insulating support, forming a hollow cathode discharge space 201. Multiple cathode holes 202 are formed on the porous lower electrode plate 212. The diameter of the cathode holes 202 is 1–5 mm, and the depth-to-diameter ratio is 2–10. The distance between the upper electrode plate 211 and the lower electrode plate 212 is 1–10 mm.

[0042] The hollow cathode remote plasma source 20 is connected to a pulsed DC power supply with a voltage adjustment range of 300–1200 V, a frequency of 1–50 kHz, and a duty cycle of 10%–80%. During process operation, the wafer to be processed 60 is placed on the wafer stage 50 in the downstream resist removal reaction zone 13, and the evacuation module 70 is activated to evacuate the vacuum reaction chamber 10 to the target process pressure. Subsequently, an O2 / Ar mixed gas is introduced into the upstream discharge zone 11 through the gas supply module 30, wherein the O2 volume fraction is 50%–95%, the Ar volume fraction is 5%–50%, the total flow rate is 500–3000 sccm, and the process pressure is maintained at 30–150 Pa.

[0043] After the hollow cathode power supply is turned on, the process gas is enhanced to ionize and dissociate in the cathode hole 202 and the inter-plate space, forming high-density oxygen active groups. The active groups are uniformly introduced into the downstream photoresist removal reaction zone 13 through the gas homogenization structure 40 (spray disk) set in the diffusion mixing zone 12, and react with the photoresist on the surface of the wafer 60 to generate volatile products such as CO, CO2, and H2O, which are discharged through the exhaust pipe 71.

[0044] In this embodiment, the temperature of the wafer stage 50 is controlled at 100–250 °C, and a low-power RF bias of 0–100 W can be selectively applied. This bias is mainly used to slightly adjust the directionality of surface reactions rather than to generate strong ion bombardment. Compared with conventional remote plasma sources, this embodiment can significantly improve the resist removal rate at a lower bias power while reducing the risk of damage to the dielectric or metal layers.

[0045] Example 2 This embodiment provides a hollow cathode enhanced remote plasma photoresist removal device, which is suitable for process scenarios with high uniformity requirements for large-size wafers such as 300 mm.

[0046] like Figure 1 As shown, the upstream hollow cathode source consists of a central hollow cathode unit 21 and an outer ring hollow cathode unit 21 surrounding it. Each hollow cathode unit 21 is connected to an independent discharge power supply. The control system can adjust the discharge power of the central region and the outer ring according to the preset process formula or the endpoint detection results.

[0047] The gas homogenization structure 40 within the diffusion mixing region 12 employs a double-layer staggered-hole spray disk structure, with the upper layer having a larger aperture than the lower layer. This increases the diffusion mixing path and weakens localized high-speed jets. For a 300 mm wafer, the power in the central region can be set to 500–1500 W, and the power in the edge region can be set to 300–1200 W. The specific values ​​are dynamically adjusted based on actual resist removal uniformity feedback. This structure effectively compensates for the loss of active particles caused by edge gas extraction and wall recombination, thereby improving the difference in resist removal rates between the wafer center and edge regions and enhancing overall process uniformity.

[0048] Example 3 This embodiment provides a hollow cathode enhanced remote plasma photoresist removal device to improve the stability and repeatability of the photoresist removal process.

[0049] Hollow cathode discharge exhibits self-pulsation phenomena in voltage or current under specific voltage, pressure, and electrode spacing conditions. These self-pulsation signals are closely related to discharge mode transitions, space charge accumulation, and the formation of virtual anodes. In this embodiment, the closed-loop control system acquires the voltage or current waveforms of the hollow cathode discharge in real time and extracts its pulse frequency, amplitude, or duty cycle characteristics to determine whether the hollow cathode remote plasma source 20 is in a stable enhanced discharge range.

[0050] When the self-pulse frequency is detected to be below the preset range, the control system increases the discharge voltage or decreases the cavity pressure in the downstream degumming reaction zone 13 to enhance the degree of ionization. When the pulse amplitude is detected to be too high or the discharge is unstable, the system decreases the discharge voltage, adjusts the gas ratio of the gas supply module 30, or increases the total flow rate to avoid particle generation, local overheating, or discharge extinction. This embodiment achieves multi-parameter linkage adjustment through discharge status feedback, significantly improving the consistency and controllability of the process.

[0051] Example 4 This embodiment combines two-dimensional structural layout, simulation results, and measured data to further illustrate the reliability and advantages of the hollow cathode-enhanced remote adhesive removal scheme.

[0052] like Figure 1As shown, the upstream hollow cathode remote plasma source 20, diffusion mixing region 12, gas homogenization structure 40, downstream wafer stage 50, and gas extraction and pressure control path are arranged along the same axis. A hollow cathode discharge space 201 is formed between the porous lower electrode plate 212 and the solid upper electrode plate 211. After the process gas enters the cathode hole 202 and the inter-plate gap, electrons oscillate back and forth within the cathode hole 202, effectively extending the collision path between electrons and gas molecules, thereby improving the ionization rate and dissociation efficiency of the O2 / Ar or O2 / N2 / Ar mixed gas. The gas homogenization structure 40 is located between the hollow cathode source and the wafer 60, used to redistribute the high-density active groups generated upstream and to block high-energy electrons, strong ultraviolet radiation, and some charged particles from directly reaching the surface of the wafer 60. The downstream wafer stage 50 can be optionally subjected to a low-power bias or no bias, so that the desizing reaction is mainly based on the chemical oxidation of neutral active oxygen groups.

[0053] like Figure 2 As shown, under normalized engineering simulation conditions of O2 / Ar=8:2, pressure of approximately 80 Pa, wafer stage 50 temperature of approximately 150 °C, and hollow cathode pulse voltage of approximately 800 V, a significant electron density enhancement region is formed near the hollow cathode channel, indicating that the porous hollow cathode can concentrate discharge energy in the upstream source region, effectively improving the reactive oxygen generation efficiency. After the active groups pass through the diffusion mixing region 12 and the gas homogenization structure 40, the local peak is weakened, and the normalized reaction flux on the wafer 60 surface tends to be flat. Compared with ordinary long-range plasma sources, the hollow cathode enhancement scheme maintains a higher average reaction flux and lower radial fluctuation in the wafer center to edge region, thus achieving good uniformity and low damage characteristics while taking into account the resist removal rate.

[0054] The above-described embodiments are merely illustrative of several specific implementations of the present invention, and while the descriptions are detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A hollow cathode enhanced remote plasma photoresist removal device, characterized in that, include: The vacuum reaction chamber is divided into an upstream discharge zone, a diffusion mixing zone, and a downstream debinding reaction zone along the gas flow direction. A hollow cathode remote plasma source is disposed in the upstream discharge region and includes at least one set of hollow cathode units; the hollow cathode unit includes an upper electrode plate and a lower electrode plate that are insulated from each other, a hollow cathode discharge space is formed between the upper electrode plate and the lower electrode plate, and a plurality of cathode holes are provided on the lower electrode plate; The gas supply module is connected to the upstream discharge region and is used to supply process gas to the hollow cathode remote plasma source; A gas homogenization structure is disposed in the diffusion mixing region to uniformly distribute the neutral active groups generated in the upstream discharge region to the downstream desizing reaction region and to block high-energy electrons, ions and ultraviolet radiation from directly reaching the wafer surface. A wafer stage, located in the downstream resist removal reaction zone, is used to support and heat or cool the wafer; The air extraction module is connected to the downstream degumming reaction zone and is used to maintain the process pressure inside the chamber and discharge the reaction products.

2. The hollow cathode enhanced remote plasma photoresist removal device according to claim 1, characterized in that, The gas supply module includes: A gas pipeline, connected to the upstream discharge region, is used to supply process gas to the hollow cathode remote plasma source; A mass flow controller is installed in the gas pipeline to control the mass flow rate through the gas pipeline; A valve is installed in the gas pipeline to control the opening and closing of the gas pipeline; The process gas is one or more of the following: O2, N2, Ar, H2, and CF4.

3. The hollow cathode enhanced remote plasma photoresist removal apparatus according to claim 1, characterized in that, The air extraction module includes: The exhaust pipe is connected to the downstream degumming reaction zone; A pressure control valve, installed in the exhaust pipe, is used to control the process pressure in the downstream degumming reaction zone; A vacuum pump, connected to the exhaust pipe, is used to remove reaction byproducts from the downstream degumming reaction zone.

4. The hollow cathode enhanced remote plasma photoresist removal device according to claim 1, characterized in that: The gas homogenization structure is a spray disc or an active screen; The spray plate is a single-layer perforated plate or a double-layer staggered perforated plate; The active screen has a ring-shaped porous structure.

5. The hollow cathode enhanced remote plasma photoresist removal device according to claim 1, characterized in that, The diameter of the cathode hole is 0.5–10 mm, and the depth-to-diameter ratio is 1–20. The distance between the upper electrode plate and the lower electrode plate is 0.5–20 mm.

6. The hollow cathode enhanced remote plasma photoresist removal apparatus according to claim 1, characterized in that, The wafer stage is equipped with heating and cooling channels, and the temperature controllable range of the wafer stage is 50–300℃.

7. The hollow cathode enhanced remote plasma photoresist removal apparatus according to claim 1, characterized in that, It also includes a power module, which comprises: A discharge power supply is used to drive the hollow cathode remote plasma source; A bias power supply is used to apply an radio frequency or pulse bias voltage to the wafer stage.

8. The hollow cathode enhanced remote plasma photoresist removal apparatus according to claim 7, characterized in that, The discharge power supply is a DC power supply, a pulsed DC power supply, or a radio frequency power supply. The bias power supply has a frequency of 400kHz–13.56MHz and a bias power of 0–300W.

9. The hollow cathode enhanced remote plasma photoresist removal apparatus according to claim 7, characterized in that, It also includes a closed-loop control system for acquiring the voltage, current or self-pulse signal of the hollow cathode discharge, and adjusting the discharge power, gas flow rate, chamber pressure and bias power in conjunction with the signal.

10. A method for removing photoresist using the apparatus according to any one of claims 1-9, characterized in that, Includes the following steps: S1. Place the wafer to be processed on the wafer stage in the downstream resist removal reaction area, start the vacuum module, and pump the vacuum reaction chamber to the preset process pressure. S2. Process gas is introduced into the upstream discharge area through the gas supply module, and the hollow cathode remote plasma source is turned on, so that the gas forms high-density neutral active groups in the hollow cathode discharge space. S3. Neutral active groups are uniformly introduced into the downstream photoresist removal reaction zone through the gas homogenization structure, where they react chemically with the photoresist on the wafer surface to generate volatile products, which are then discharged by the gas extraction module. S4. Adjust the resist removal rate and uniformity by controlling the temperature of the wafer stage and / or using low power bias. S5. Based on the discharge status feedback signal, adjust the process parameters in a closed loop until the adhesive removal is completed.

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