Plasma processing apparatus and substrate processing region ion concentration regulation method

Abstract

The application relates to the field of semiconductor technology, in particular to a plasma processing device and a substrate processing area ion concentration regulation method thereof, and solves the technical problems of long process gas switching time and low gas inlet and outlet efficiency caused by using a remote plasma source or an ion filtering grid in the prior art. The application sets a first conductive structure outside a substrate processing area in a process chamber, controls the state of the first conductive structure, for example, is at a negative potential or makes the first conductive structure float, is at a positive potential or is grounded, so that when the process chamber operates in a first process based on free radicals, the first conductive structure is negatively charged to realize accurate separation of free radicals and ions; the diffusion of ions to the substrate is effectively inhibited, at the same time, the RPS or the ion filtering grid does not need to be set, the gas inlet and outlet efficiency is improved, and the productivity is improved.

Description

Technical Field

[0001] This application relates to the field of semiconductor technology, and more specifically, to plasma processing equipment and a method for controlling the ion concentration in the substrate processing area. Background Technology

[0002] Radical etching is a dry etching technique that removes materials by relying on the chemical reaction between highly reactive neutral free radicals and the material surface. It has the advantages of no physical damage, ultra-high selectivity, and atomic-level precision.

[0003] The modification step in atomic layer etching (ALE) has similar technical requirements to free radical etching, namely, a sufficient concentration of free radicals and avoiding the introduction of ions that would cause the pure free radical reaction to deteriorate into reactive ion etching (RIE).

[0004] To meet this technical requirement, existing technologies generally introduce a remote plasma source (RPS) or divide the process chamber into upper and lower chambers. The upper chamber is used to excite the plasma, and the lower chamber is used for radical-based substrate treatment. The two chambers are separated by a grid or ion trap to filter out ions. However, these solutions significantly reduce intake and exhaust efficiency due to the introduction of RPS or grid structures, hindering the rapid supply and evacuation of process gases. Especially when implementing multi-step cyclic processes such as ALE, it is difficult to quickly switch between the two gases in the modification and stripping stages. Furthermore, the upper and lower partitions within the chamber greatly increase the internal volume, particularly the space above the substrate, further increasing the gas exchange time between the modification and stripping stages, reducing process efficiency, and hindering capacity improvement.

[0005] Therefore, there is an urgent need for a plasma processing device and method that does not require RPS or ion filter grids and allows for controllable ion concentration in the substrate processing area. Summary of the Invention

[0006] The purpose of this application is to overcome the shortcomings of the prior art and provide a plasma processing device and a method for controlling the ion concentration in the substrate processing area. This method can effectively suppress the diffusion of ions into the substrate through electrical connection control of the first conductive structure, while eliminating the need for RPS or ion filter grids, thereby improving intake and exhaust efficiency and helping to increase production capacity.

[0007] As a first aspect of this application, this application provides a plasma processing apparatus, including a process chamber sealed by a dielectric window, and a base disposed therein for supporting a substrate to be processed. A radio frequency (RF) coil is disposed outside the dielectric window. The RF coil is electrically connected to an active RF source to feed RF energy into the process chamber. The process chamber has an exhaust port for communication with the vacuum pumping assembly, wherein... The process chamber includes a substrate processing area, which is located above the axial projection of the base. The process chamber is provided with an edge air inlet at its radial edge; The radio frequency coil includes a first coil structure disposed outside the axial projection of the base. A first conductive structure is disposed within the process chamber, and the first conductive structure is located outside the substrate processing area. The edge air inlet is configured to blow a first process gas toward the substrate processing area; The source radio frequency is configured to feed radio frequency energy into the first coil structure to excite the first process gas into plasma on the upstream side of the substrate processing region; The first conductive structure is configured to be in a first state when the process chamber is operating a radical-based first process, the first state including a negative potential or a floating state of the first conductive structure to attract positive ions upstream of the substrate processing region.

[0008] In one embodiment of this application, the first conductive structure switches to a second state when the process chamber is operating at least an ion-based second process, the second state including a positive potential or a grounded state.

[0009] In one embodiment of this application, the plasma processing apparatus further includes: A first control circuit, wherein the first control circuit is connected to the first conductive structure; When the process chamber is operating in the first process, the first control circuit operates in a first operating mode, which includes outputting a negative voltage or making the first conductive structure float to ground, so that the first conductive structure is in the first state.

[0010] In one embodiment of this application, when the process chamber is operating in at least an ion-based second process, the first control circuit operates in a second operating mode, the second operating mode including outputting a positive voltage or grounding the first conductive structure so that the first conductive structure is in a second state.

[0011] In one embodiment of this application, the first control circuit includes: a first power supply, which can selectively output a positive pulse voltage or a negative pulse voltage; and a first switch, which controls the connection or disconnection between the first conductive structure and the first power supply; and / or The first control circuit includes a second switch, which controls the first conductive structure to be grounded or floating.

[0012] In one embodiment of this application, the plasma processing device further includes a third control circuit for controlling whether the base is grounded or floating. The first conductive structure is disposed on the outer periphery of the side of the base and is electrically connected to the base.

[0013] In one embodiment of this application, the first conductive structure is insulated and fixed to the outer periphery of the side of the base, and the first conductive structure and the base are electrically connected in a switchable manner through the first control circuit, and the base is grounded.

[0014] In one embodiment of this application, the first conductive structure is configured as a conductive liner of the process chamber. The first end of the liner is insulated and fixed to the side wall of the process chamber and electrically connected to it in a switchable manner through a fourth control circuit. The second end of the liner is electrically connected to the base. The fourth control circuit is switched on and off synchronously with the third control circuit.

[0015] In one embodiment of this application, the first conductive structure is configured as a conductive liner of the process chamber. The first end of the liner is insulated and fixed to the side wall of the process chamber and electrically connected to it in a switchable manner through a fourth control circuit. The second end of the liner is insulated and fixed to the base and electrically connected to it in a switchable manner through the first control circuit. The fourth control circuit is switched on and off synchronously with the first control circuit.

[0016] In one embodiment of this application, a bias power supply is further included. The bias power supply is electrically connected to the base and is used to apply a bias voltage to the substrate. In the first process, the bias power supply is in a closed state or substantially at a positive potential. In one embodiment of this application, the first conductive structure is disposed between the edge air inlet and the exhaust outlet, such that when the first conductive structure is in a first state, positive ions on the upstream side of the substrate processing area are deflected towards the direction of the exhaust outlet.

[0017] In one embodiment of this application, the first conductive structure includes a first conductive portion located between the substrate processing region and the axial projection region of the first coil structure, and the first process gas flows through the first conductive portion to reach the substrate processing region.

[0018] In one embodiment of this application, the first conductive structure includes a second conductive portion located on the side of the base, and the current resistance of the first conductive portion is less than the current resistance of the second conductive portion. In one embodiment of this application, the radio frequency coil includes a second coil structure at least partially disposed within the axial projection of the base. In the first process, the second coil structure has no power output or outputs in a power pulse mode, and the average power output of the second coil structure is less than the average power output of the first coil structure.

[0019] In one embodiment of this application, the solid flow-blocking projection area of ​​the first conductive part is less than 5% of the net cross-sectional area of ​​the flow channel perpendicular to the airflow direction between the base and the dielectric window.

[0020] In one embodiment of this application, the first conductive part has a first air vent with an opening rate greater than 90%, and the length-to-diameter ratio of the through hole is less than 0.5.

[0021] In one embodiment of this application, the substrate to be processed does not have a grid structure directly above it, and the grid structure is used to reduce ions flowing to the substrate.

[0022] In one embodiment of this application, the maximum distance from the dielectric window to the top surface of the base is less than 1 / 4 of the maximum inner diameter of the sidewall of the process chamber.

[0023] As a second aspect of this application, this application also provides a method for controlling the ion concentration in a substrate processing region, applied to the aforementioned plasma treatment device, wherein the control method includes: A process chamber having a first conductive structure is provided, the first conductive structure being located outside the substrate processing region; The process chamber is operated in a free radical-based first process, and the edge air inlet is controlled to blow the first process gas toward the substrate processing area. The control source feeds radio frequency energy into the first coil structure located outside the axial projection of the base to excite the first process gas into plasma on the upstream side of the substrate processing region; The first conductive structure is controlled to be in a first state, which includes a negative potential or a floating state, so as to attract positive ions on the upstream side of the substrate processing region.

[0024] In one embodiment of this application, the process chamber is operated in a second process based at least on ions, and the first conductive structure is controlled to switch to a second state, which includes a positive potential or a grounded state.

[0025] In one embodiment of this application, in the first process, the output of the first coil structure is a power pulse mode.

[0026] In one embodiment of this application, the process chamber is operated in a second process based at least on ions, and a second process gas is supplied to the substrate processing region; a control source radio frequency feeds radio frequency energy into a radio frequency coil to excite the second process gas into plasma; and the first conductive structure is controlled to be in a second state, the second state including a positive potential or a grounded state, to suppress the attraction of positive ions.

[0027] This application involves setting a first conductive structure outside the substrate processing area within a process chamber. When the process chamber is operating a free radical-based first process (e.g., substrate modification), the first conductive structure is negatively charged or is made to float, attracting positive ions upstream of the substrate processing area. This causes the ions to deflect away from the substrate's orientation, increasing the probability of ion collision and annihilation in the upstream region and reducing the number of ions diffusing to the substrate. Free radicals, being uncharged, are not easily attracted by the first conductive structure and can diffuse into the substrate processing area, ultimately completing the free radical-based processing reaction while avoiding ion interference. If substrate modification is achieved through a chemical reaction between free radicals and the substrate surface, ion degradation of the modification process can be avoided, preventing the modification process from deteriorating into reactive ion etching.

[0028] The first conductive structure is set in the process chamber without introducing additional RPS or ion shielding grids, which facilitates the miniaturization of the chamber volume and the rapid switching of process gas intake and exhaust, thereby improving process efficiency and increasing production capacity. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0030] Figure 1 The diagram shown is a structural schematic of a plasma processing device provided in an embodiment of this application.

[0031] Figure 2 The diagram shown is a structural schematic of a plasma processing device provided in another embodiment of this application.

[0032] Figure 3 The diagram shown is a structural schematic of a plasma processing device provided in another embodiment of this application.

[0033] Figure 4 The diagram shown is a structural schematic of a plasma processing device provided in another embodiment of this application.

[0034] Figure 5 The diagram shown is a structural schematic of a plasma processing device provided in another embodiment of this application.

[0035] Figure 6 The diagram shown is a structural schematic of a plasma processing device provided in another embodiment of this application.

[0036] Figure 7The diagram shown is a structural schematic of a plasma processing device provided in another embodiment of this application.

[0037] Figure 8 The diagram shown is a structural schematic of a plasma processing device provided in another embodiment of this application.

[0038] Figure 9 The diagram shown is a structural schematic of a plasma processing device provided in another embodiment of this application.

[0039] Figure 10 The diagram shown is a structural schematic of a plasma processing device provided in another embodiment of this application.

[0040] Figure 11 The diagram shown is a structural schematic of a plasma processing device provided in another embodiment of this application.

[0041] Figure 12 The diagram shown is a structural schematic of a plasma processing device provided in another embodiment of this application.

[0042] Figure 13 The diagram shown is a structural schematic of a plasma processing device provided in another embodiment of this application.

[0043] Figure 14 The diagram shown is a structural schematic of a plasma processing device provided in another embodiment of this application.

[0044] Figure 15 The diagram shown is a flowchart illustrating a method for controlling the ion concentration in a substrate processing region according to an embodiment of this application.

[0045] Figure 16 The diagram shown is a flowchart illustrating a method for controlling the ion concentration in a substrate processing region according to an embodiment of this application.

[0046] Figure label: 10-Process chamber, 11-Exhaust port, 20-Dielectric window, 30-Base, 40-Edge air intake structure, 51-First source RF, 52-Bias power supply, 53-Second source RF, 61-First coil structure, 62-Second coil structure, 70-First conductive structure, 71-Second electrode, 72-First air vent, 73-Second air vent, 74-Second conductive part, 75-First conductive part, 76-Second conductive structure, 8-First control circuit, 80-Second control circuit, 81-First power supply, 82-Second power supply, 83-Third control circuit, 84-Fourth control circuit, 90-Substrate to be processed. Detailed Implementation

[0047] The technical solutions of this application will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0048] Exemplary System As a first aspect of this application, Figure 1 The diagram shown is a structural schematic of a plasma processing device according to an embodiment of this application. Figure 1 As shown, a plasma processing device includes: The process chamber 10 is sealed by a dielectric window 20. The process chamber 10 has an exhaust port 11. The exhaust port 11 is used to communicate with a vacuum pumping assembly to evacuate the process chamber 10. A base 30 is provided inside the process chamber 10, which is used to support the substrate 90 to be processed.

[0049] Generally, the base 30 may include a lower electrode assembly electrically connected to a bias power supply 52, which applies a bias voltage to the substrate to control the bombardment energy of ions in the plasma. In the first process based on free radical processing, the bias power supply 52 is typically off or substantially positive to suppress the formation of a plasma sheath on the substrate and reduce the substrate's attraction to positive ions. It can be understood that "substantially positive" means that in the first process, the time integral of the output voltage of the bias power supply 52 is positive.

[0050] Radial (e.g., process chamber 10) Figure 1 An edge air inlet is provided at the edge (shown in the X direction). The process chamber 10 includes a substrate processing region Q, wherein the substrate processing region Q is located within the projection range of the base 30 along the process chamber axis.

[0051] A first conductive structure 70 is disposed within the process chamber 10, and the first conductive structure 70 is located outside the substrate processing region Q.

[0052] The RF coil and the source RF source are arranged. The RF coil is positioned outside the dielectric window 20 and is electrically connected to the source RF source. For example, the dielectric window 20 is a planar dielectric window, and the RF coil is positioned above the dielectric window 20. The RF energy output from the source RF source is fed into the process chamber 10 through the RF coil. Wherein, as... Figure 1 As shown, the RF coil includes a first coil structure 61, which is disposed outside the axial projection of the base 30 onto the process chamber 10, wherein the axial direction is as shown in the figure. Figure 1The Y direction is shown. The source radio frequency includes a first source radio frequency 51, which is electrically connected to a first coil structure 61. Through the first coil structure 61, the radio frequency energy output by the first source radio frequency 51 is fed into the edge region within the process chamber 10.

[0053] In one embodiment, the process chamber 10 operates on a first radical-based process, such as radical etching or modification processes.

[0054] The edge inlet structure 40 blows a first process gas into the process chamber 10 through the edge inlet port. This first process gas forms plasma on the upstream side of the substrate processing region Q under the excitation of radio frequency energy. It can be understood that, since it is an edge inlet, the upstream side of the substrate processing region Q is located on its radial periphery, that is, the upper edge region of the process chamber 10.

[0055] Taking substrate modification as an example, during the substrate modification process, free radicals participate in chemical reactions to form a modified layer on the surface of the substrate to be treated, thereby achieving surface modification: When the first conductive structure 70 is in a first state (e.g., negative potential), positive ions in the plasma upstream of the substrate processing region Q are attracted by the first conductive structure 70, guiding the ions to deviate from the gas inlet direction and accelerate towards the first conductive structure 70. On the one hand, this reduces ion diffusion towards the substrate; on the other hand, some ions, after being attracted, collide with the first conductive structure 70 and annihilate, thus being rapidly lost. Meanwhile, free radicals are not easily affected by the first conductive structure 70 and deviate from the gas inlet direction, easily diffusing along the gas inlet direction to the substrate processing region Q. Ultimately, the free radicals react chemically with the surface of the substrate to be treated, completing the substrate modification and forming a modified layer. This avoids the ion degradation modification process from deteriorating into reactive ion etching.

[0056] When the first conductive structure 70 is in the floating state in the first state, the floating state allows electrons to collide with its surface and accumulate to form a plasma sheath. It also attracts positive ions from the plasma upstream of the substrate processing region Q, guiding them away from the inlet direction and accelerating them towards the first conductive structure 70. This reduces ion diffusion towards the substrate, and some attracted ions collide with the first conductive structure 70 and annihilate, resulting in rapid loss. Free radicals are less affected by the first conductive structure 70 and tend to diffuse along the inlet direction to the substrate processing region Q. Ultimately, free radicals react chemically with the surface of the substrate to be treated, completing substrate modification and forming a modified layer. This avoids the ion degradation modification process from deteriorating into reactive ion etching.

[0057] Similarly, this embodiment also helps to realize radical-based substrate reactions such as radical etching.

[0058] By controlling the potential of the first conductive structure 70, during the substrate modification stage, the negatively charged first conductive structure 70 enables precise separation of free radicals and ions. During the modification layer peeling stage, the first conductive structure 70 only serves a confinement function, allowing ions to survive and controlling the ion concentration in the substrate treatment area, thus avoiding the impact of excessive or insufficient ions on the process effect. Furthermore, by simply placing the first conductive structure 70 within the process chamber 10, without introducing additional RPS, ion traps, spray heads, or other components that hinder gas switching between different steps, the chamber volume can be miniaturized, and rapid gas intake and exhaust switching can be achieved, thereby improving process efficiency and increasing throughput. This is particularly beneficial for increasing throughput in multi-step cyclic processes such as ALE.

[0059] In one embodiment, the edge air intake structure 40 further includes an intake valve, which is connected to the edge air intake port in a one-to-one manner, and the intake valve is directly fixed to the air inlet end of the edge air intake port. This minimizes intake delay, further improving intake and exhaust efficiency and increasing production capacity. Preferably, the intake valve is a diaphragm valve, such as an ALD valve, with a switching response time of less than 5ms, to further improve the intake response rate.

[0060] In one embodiment, process chamber 10 operates at least in a second ion-based process.

[0061] For example, the second process is a modified layer stripping process, which removes the modified layer from the surface of the substrate 90 by bombarding the material on the surface of the substrate 90. In this case, the air intake structure can be either a center air intake or an edge air intake.

[0062] The inlet structure blows a second process gas into the process chamber 10, which forms plasma under the excitation of radio frequency energy. When the first conductive structure 70 is in a second state, including a positive potential or a grounded state, the formation of a plasma sheath on the first conductive structure 70 is suppressed, so that the first conductive structure 70 has less influence on ions, and the ion concentration in the substrate processing area Q is increased, which can ensure the stripping efficiency and quality.

[0063] In one embodiment, by feeding the first coil structure 61 with higher radio frequency power in the second process than in the first process, it is beneficial to counteract the effect of the first conductive structure 70 on plasma excitation when it is in the second state and to increase the ion concentration.

[0064] In one embodiment of this application, as Figures 1-12 As shown, the plasma processing equipment also includes a first control circuit 8, which is connected to the first conductive structure 70. When the process chamber 10 is running in the first process described above, the first control circuit 8 operates in a first working mode, that is, outputting a negative voltage or setting the first conductive structure to float, so that the first conductive structure 70 is at a negative potential or the first conductive structure is in a floating state.

[0065] In one embodiment, when the process chamber 10 is operating in the second process described above, the first control circuit 8 operates in the second operating mode described above, that is, outputting a positive voltage or grounding the first conductive structure, so that the first conductive structure 70 is at a positive potential or in a grounded state.

[0066] For example, the specific structure of the first control circuit 8 can adopt the following three structures: (1) such as Figure 1 As shown, the first control circuit 8 includes a first power supply 81 and a first switch K1. The first power supply 81 can selectively output a positive pulse voltage or a negative pulse voltage. One end of the first switch K1 is connected to the first conductive structure 70, and the other end of the first switch K1 is connected to the first power supply 81. When the first power supply 81 outputs a negative pulse voltage and the first switch K1 is closed, the first control circuit 8 outputs a negative voltage, which causes the first conductive structure 70 to be at a negative potential, i.e., the first conductive structure is in a first state.

[0067] When the first power supply 81 outputs a positive pulse voltage and the first switch K1 is closed, the first control circuit 8 outputs a positive voltage, which makes the first conductive structure 70 a positive potential, that is, the first conductive structure is in the second state.

[0068] It should be noted that the first power supply 81 and the first switch K1 can exist independently of each other, or they can be integrated into a variable DC power supply. That is, the first control circuit 8 includes a variable DC power supply, which can selectively output positive or negative voltage.

[0069] (2) For example Figure 2 As shown, the first control circuit 8 includes a second switch K2. One end of the second switch K2 is connected to the first conductive structure 70, and the other end of the second switch K2 is grounded. When the second switch K2 is open, the first control circuit 8 is floating, which allows the first conductive structure 70 to be in a floating state, i.e., the first conductive structure 70 is in a first state. When the second switch K2 is closed, the first control circuit 8 is grounded, which allows the first conductive structure 70 to be in a grounded state, i.e., the first conductive structure 70 is in a second state.

[0070] (3) such as Figures 3-10 As shown, the first control circuit 8 includes a first power supply 81, a first switch K1, and a second switch K2; wherein, one end of the first switch K1 is connected to the first conductive structure 70, and the other end of the first switch K1 is connected to the first power supply 81. One end of the second switch K2 is connected to the first conductive structure 70, and the other end of the second switch K2 is grounded.

[0071] When the first power supply 81 outputs a positive pulse voltage and the first switch K1 is closed and the second switch K2 is open, the first control circuit 8 outputs a positive pulse voltage, that is, it operates in the second working mode, which makes the first conductive structure 70 at a positive potential.

[0072] When the first power supply 81 outputs a negative pulse voltage and the first switch K1 is closed and the second switch K2 is open, the first control circuit 8 outputs a negative pulse voltage, that is, it operates in the first working mode, which can make the first conductive structure 70 be at a negative potential.

[0073] When the first switch K1 is open and the second switch K2 is closed, the first control circuit 8 is grounded, that is, it works in the second working mode, which can make the first conductive structure 70 be in a grounded state.

[0074] When the first switch K1 is open and the second switch K2 is open, the first control circuit 8 is in a floating state, that is, it works in the first working mode, which makes the first conductive structure 70 in a floating state.

[0075] In one embodiment, the first conductive structure 70 is insulated and fixed to the outer periphery of the side of the base 30, that is, there is no direct electrical connection between the first conductive structure 70 and the base 30, and the base 30 is grounded. The first conductive structure 70 is sleeved on the outer periphery of the side of the base 30. The operating mode of the first control circuit 8 is to output positive voltage, output negative voltage, float ground, or ground. Correspondingly, the first control circuit 8 is connected between the first conductive structure 70 and the base 30, such as... Figure 11 As shown, the first control circuit 8 is connected between the first conductive structure 70 and the base 30, that is, the first conductive structure 70 and the base 30 can be electrically connected by the first control circuit 8 so that the first conductive structure 70 is in a grounded state or in a floating state.

[0076] Correspondingly, the structure of the first control circuit 8 can adopt the following structure: (4) The first control circuit 8 includes at least one control switch, for example, as shown in 12. The first control circuit 8 includes an eighth switch K8. By controlling the opening or closing of the eighth switch K8, the first conductive structure 70 can be controlled to be in a floating state or a grounded state.

[0077] (5) In addition to the first power supply 81 and the first switch K1 (the first power supply 81 is connected to the first switch K1 and the other end of the first switch K1 is connected to the first conductive structure 70) and / or the second switch K2 (one end of the second switch K2 is grounded and the other end is connected to the first conductive structure), the first control circuit 8 also includes an eighth switch K8, wherein one end of the eighth switch K8 is connected to the base 30 and the other end is connected to the first conductive structure 70.

[0078] For example, when the first control circuit 8 includes a first power supply 81, a first switch K1, a second switch K2, and an eighth switch K8, when the eighth switch K8 and / or the second switch K2 are closed and the first switch K1 is open, the first conductive structure 70 can be grounded. When the eighth switch K8 is open and both the second switch K2 and the first switch K1 are open, the first conductive structure 70 can be floating. When the eighth switch K8 and the second switch K2 are open, the first switch K1 is closed, and the first power supply 81 outputs a positive voltage, the first conductive structure 70 is positively charged. When both the eighth switch K8 and the second switch K2 are open, the first switch K1 is closed, and the first power supply 81 outputs a negative voltage, the first conductive structure 70 is at a negative potential.

[0079] In one embodiment, the first conductive structure 70 is insulated and fixed to the outer periphery of the side of the base 30, meaning there is no direct electrical connection between the first conductive structure 70 and the base 30. The base 30 is grounded, and the first conductive structure 70 is sleeved on the outer periphery of the side of the base 30, forming a liner within the process chamber 10. A first end of the liner is insulated and fixed to the side wall of the process chamber 10, and a second end of the liner is insulated and fixed to the side wall of the base 30. For example, the first end of the liner is near the upper end of the dielectric window 20, and the second end is near the lower end of the base 30.

[0080] Correspondingly, such as Figure 12 As shown, in addition to the first control circuit 8 described above, the plasma processing equipment also includes a fourth control circuit 84. The fourth control circuit 84 is connected between the first end of the liner (i.e., the first conductive structure 70) and the side wall of the process chamber 10, and the second end of the liner is connected to the base 30 via the first control circuit 8. The fourth control circuit 84 allows for a switchable electrical connection between the liner (i.e., the first conductive structure 70) and the side wall of the process chamber 10. Since the side wall of the process chamber 10 is typically grounded, the switching on / off state of the fourth control circuit 84 can either ground the first conductive structure 70 or place it in a floating state. Similarly, the first control circuit 8 allows for a switchable electrical connection between the liner (i.e., the first conductive structure 70) and the base 30. Since the base 30 is grounded, the switching on / off state of the first control circuit 8 can either ground the first conductive structure 70 or place it in a floating state.

[0081] In this embodiment, the two ends of the liner (i.e., the first conductive structure 70) are connected to the side wall of the process chamber 10 and the base 30 respectively in a switchable manner. Since both the side wall of the process chamber 10 and the base 30 are grounded, the on / off states of the fourth control circuit 84 and the first control circuit 8 are consistent. That is, when both the fourth control circuit 84 and the first control circuit 8 are off, the first conductive structure 70 is in a floating state. When both the fourth control circuit 84 and the first control circuit 8 are on, the first conductive structure 70 is in a grounded state. Compared to the liner being grounded at only one end, double-end grounding allows the liner to have an overall equipotential, which is beneficial for plasma confinement, avoids arc discharge, and improves the uniformity of plasma treatment in the second process.

[0082] For example, such as Figure 12 As shown, the first control circuit 8 includes an eighth switch K8, and the fourth control circuit includes a seventh switch K7. Simultaneously controlling the eighth switch K8 and the seventh switch K7 to open allows the first control circuit 8 and the fourth control circuit 84 to disconnect synchronously, thus placing the first conductive structure 70 in a floating state. Simultaneously controlling the eighth switch K8 and the seventh switch K7 to close allows the first control circuit 8 and the fourth control circuit 84 to connect synchronously, thus placing the first conductive structure 70 in a grounded state.

[0083] In another embodiment of this application, such as Figure 13 As shown, the first conductive structure 70 is sleeved on the outer periphery of the side of the base 30, and the first conductive structure 70 is electrically connected to the base 30. The plasma processing equipment also includes a third control circuit 83, which controls the base 30 to be grounded or floating.

[0084] When the third control circuit 83 operates in ground mode, the first conductive structure 70 is in a grounded state, i.e., in the second state. When the third control circuit 83 operates in floating mode, the first conductive structure 70 is in a floating state, i.e., in the first state.

[0085] For example, the third control circuit 83 includes at least one switch, which controls the on / off state of the third control circuit 83. For instance, as... Figure 13 As shown, the third control circuit includes a sixth switch K6, with both ends of the sixth switch K6 grounded and electrically connected to the base 30. When the sixth switch K6 is closed, the third control circuit operates in grounded mode, and the first conductive structure 70 is in a grounded state. When the sixth switch K6 is opened, the third control circuit operates in floating mode, and the first conductive structure 70 is in a floating state.

[0086] In one embodiment, such as Figure 14 As shown, the first conductive structure 70 is configured as a liner within the process chamber 10. The first end of the liner is insulated and fixed to the side wall of the process chamber 10. Correspondingly, as... Figure 14 As shown, the plasma processing equipment also includes a fourth control circuit 84 and a third control circuit 83. One end of the liner (i.e., the first conductive structure 70) is electrically connected to the side wall of the process chamber 10 via the fourth control circuit 84, and the second end of the liner (i.e., the first conductive structure 70) is electrically connected to the base 30. The third control circuit 83 is used to control whether the base 30 is grounded or floating.

[0087] Since the sidewalls of the process chamber 10 are typically grounded, the first conductive structure 70 can be grounded or floating by switching the fourth control circuit 84 on and off. The base 30 can be grounded by the third control circuit 83. Therefore, the first conductive structure 70 can be grounded or floating by switching the third control circuit 83 on and off.

[0088] Since one end of the liner (i.e., the first conductive structure 70) is connected to the side wall of the process chamber 10 via a fourth control circuit, and the other end is electrically connected to the base 30, the third control circuit 83 controls whether the base 30 is grounded. Therefore, the on / off states of the fourth control circuit 84 and the third control circuit 83 are consistent; that is, when both the fourth control circuit 84 and the third control circuit 83 are off, the first conductive structure 70 is in a floating state. When both the fourth control circuit 84 and the third control circuit 83 are on, the first conductive structure 70 is in a grounded state. Compared to grounding only one end of the liner, double-end grounding allows the liner to have an overall equipotential, which is beneficial for plasma confinement, avoids arc discharge, and improves the uniformity of plasma treatment in the second process. Furthermore, considering that the contact end between the liner and the base 30 is located within the process processing area, keeping the liner and the base 30 electrically connected at all times to control whether the far end of the base 30 is grounded or biased is beneficial for placing circuit devices far away from the process processing area, avoiding the influence of radio frequency and plasma, and improving equipment reliability.

[0089] For example, such as Figure 14 As shown, the third control circuit 83 includes a sixth switch K6, and the fourth control circuit includes a seventh switch K7. Simultaneously controlling the sixth switch K6 and the seventh switch K7 to open will cause the third control circuit 83 and the fourth control circuit 84 to disconnect synchronously, so that the first conductive structure 70 is in a floating state. Simultaneously controlling the sixth switch K6 and the seventh switch K7 to close will cause the third control circuit 83 and the fourth control circuit 84 to connect synchronously, so that the first conductive structure 70 is in a grounded state.

[0090] In one embodiment of this application, the first conductive structure 70 is disposed between the edge air inlet and the exhaust outlet 11, such as... Figure 1 , Figure 3 as well as Figure 5As shown, when the first conductive structure 70 is in the first state, the positive ions on the upstream side of the substrate processing region Q are deflected toward the exhaust port 11.

[0091] In one embodiment, the first conductive structure may also be a segmented ring electrode, with each segment connected to an independent control circuit to achieve regional regulation of ion concentration.

[0092] In another embodiment of this application, such as Figure 4 As shown, the first conductive structure 70 includes a first conductive portion 75 located between the substrate processing region Q and the axial projection region of the first coil structure 61. A first process gas flows through the first conductive portion 75 to reach the substrate processing region Q. At least one first gas inlet 72 is provided on the first conductive portion 75. The first process gas flows through the first conductive portion 75 to reach the substrate processing region Q via the first gas inlet 72 and the edge inlet. The first conductive portion 75 allows it to directly adsorb ions from the plasma, causing them to collide and annihilate, thereby significantly reducing the ion concentration.

[0093] In one embodiment, the opening ratio of the first conductive part 75 is greater than 90%, and the aspect ratio of the through hole is less than 0.5, so as to reduce the flow resistance of the first conductive part 75 and reduce its impact on the intake and exhaust efficiency.

[0094] In one embodiment, the solid flow-blocking projected area of ​​the first conductive part 75 is less than 5% of the net cross-sectional area of ​​the flow channel perpendicular to the airflow direction between the base 30 and the dielectric window 20. It is understood that the first conductive part 75 may also adopt a non-perforated thin plate structure, such as a plate extending along the air intake direction, so as to minimize the flow resistance while adsorbing ions in the plasma, thereby making the impact on the intake and exhaust efficiency negligible.

[0095] In one embodiment, such as Figure 4 , Figure 8 as well as Figure 9 As shown, the first conductive structure 70 also includes a second conductive portion 74 located on the side of the process chamber 10. The flow resistance of the first conductive portion 75 is less than that of the second conductive portion 74. This causes the particle diffusion direction to be generally biased towards the substrate processing area, rather than flowing directly to the exhaust port 11, thereby improving processing efficiency.

[0096] In one embodiment, the second conductive portion 74 is provided with at least one second vent 73. In one embodiment, such as... Figure 4 As shown, the length extension direction of the first gas guide port 72 is parallel to the radial direction X of the process chamber 10, which allows the first process gas to smoothly enter the substrate processing area Q; the length extension direction of the second gas guide port 73 is parallel to the axial direction Y of the process chamber 10, which allows the gas to smoothly exit the process chamber 10.

[0097] In one embodiment, such as Figure 4 As shown, the angle between the first conductive part 75 and the second conductive part 74 is a right angle or an obtuse angle, so as to reduce the risk of arc discharge between the corner and the substrate or base 30 component, and to cover a larger plasma area, which is beneficial to reduce ions in the substrate processing area.

[0098] In another embodiment of this application, the first conductive structure 70 is configured as a conductive liner originally disposed within the process chamber 10, such as an edge electrode in the lower electrode assembly located below the substrate 90 to be processed. For example, as Figure 5 As shown, the plasma processing apparatus includes an electrode assembly disposed below a substrate 90 to be processed, wherein the electrode assembly includes a first electrode and a second electrode 71 surrounding the first electrode; wherein a first conductive structure 70 is the second electrode 71. The first conductive structure 70 reuses the second electrode 71 (edge ​​electrode).

[0099] In one embodiment, such as Figure 5 As shown, the upper surface of the first conductive structure 70 is located below the upper surface of the base 30.

[0100] In another embodiment of this application, the first conductive structure 70 is configured as a second electrode 71 in the lower electrode assembly located below the substrate 90 to be processed. This application also provides a second conductive structure 76 within the process chamber 10, such as... Figure 6 , Figure 9 as well as Figure 10 As shown, the plasma processing equipment also includes: a second conductive structure 76 disposed in the process chamber 10, and the second conductive structure 76 is disposed above the second electrode 71; a second control circuit 80, which is connected to the second conductive structure 76, and the second control circuit 80 can selectively operate in a first operating mode (outputting a negative voltage or making the second conductive structure float) and a second operating mode (outputting a positive voltage or making the second conductive structure ground).

[0101] When process chamber 10 is operating in the first process, the second control circuit 80 operates in the first operating mode to control the second conductive structure 76 to obtain a negative potential or to make the second conductive structure float to attract positive ions in the plasma; when process chamber 10 is operating in the second process, the second control circuit 80 operates in the second operating mode to control the second conductive structure 76 to obtain a positive potential or to make the second conductive structure grounded. Its principle is the same as the working principle of the first control circuit 8 controlling the first conductive structure 70, and will not be described again here.

[0102] In one embodiment, the circuit of the first control circuit 8 is as follows: Figure 1 or Figure 2 The circuit shown corresponds to, for example, Figure 6As shown, the second control circuit 80 includes: a second power supply 82; a third switch K3, one end of the third switch K3 is connected to the second power supply 82, and the other end of the third switch K3 is connected to the second conductive structure 76.

[0103] When the second power supply 82 outputs a positive voltage and the third switch K3 is closed, the second control circuit 80 outputs a positive voltage, and the second conductive structure 76 is positively charged. When the second power supply 82 outputs a negative voltage and the third switch K3 is closed, the second control circuit 80 outputs a negative voltage, and the second conductive structure 76 is negatively charged.

[0104] It should be noted that the operating mode controlled by the first control circuit 8 and the operating mode of the second control circuit 80 are controlled independently of each other.

[0105] In one embodiment, the circuit of the first control circuit 8 is as follows: Figure 3 or Figure 1 The circuit shown is as follows: Figure 9 As shown, the second control circuit 80 includes a fourth switch K4, one end of which is connected to the first power supply 81, and the other end of which is connected to the second conductive structure 76.

[0106] That is, the second control circuit 80 reuses the first power supply 81 in the first control circuit 8.

[0107] When the first power supply 81 outputs a positive voltage, and both the fourth switch K4 and the first switch K1 are closed, both the first control circuit 8 and the second control circuit 80 output positive voltage, and both the first conductive structure 70 and the second conductive structure 76 are positively charged.

[0108] When the first power supply 81 outputs a negative voltage, and both the fourth switch K4 and the first switch K1 are closed, both the first control circuit 8 and the second control circuit 80 output negative voltages, and both the first conductive structure 70 and the second conductive structure 76 are negatively charged.

[0109] In one embodiment, the circuit of the first control circuit 8 is as follows: Figure 1 or Figure 2 The circuit shown corresponds to, for example, Figure 10 As shown, the second control circuit 80 includes a fifth switch K5, one end of which is connected to the second conductive structure 76, and the other end of which is grounded.

[0110] When the fifth switch K5 is closed, the second control circuit 80 is grounded, and the second conductive structure 76 is in a grounded state. When the fifth switch K5 is open, the second control circuit 80 is floating, and the second conductive structure 76 is in a floating state.

[0111] The operating modes of the first control circuit 8 and the second control circuit 80 are controlled independently of each other.

[0112] In one embodiment of this application, the substrate 90 to be processed does not have a grid structure directly above it. The grid structure is used to reduce the flow of ions to the substrate. Such a grid structure significantly increases the space from the substrate 90 to the top of the process chamber 10, reduces the intake and exhaust efficiency, and is not conducive to the direct and rapid control of the ion concentration in the substrate processing area by the RF coil. It has a certain delay hysteresis, which is not conducive to improving process efficiency.

[0113] In another embodiment of this application, the maximum distance from the dielectric window 20 to the top surface of the base 30 is less than 1 / 4 of the maximum inner diameter of the sidewall of the process chamber 10. This flattens the plasma space above the substrate. Combined with the edge plasma excitation mode in the first process, the flattened space increases the probability of collisional annihilation of ions during radial diffusion to the substrate, further reducing the possibility of ions diffusing to the substrate.

[0114] In one embodiment of this application, in the first process, the first coil structure 61 outputs a power pulse mode. That is, the first source radio frequency 51 outputs pulse power to the first coil structure 61, and the first coil structure 61, driven by the first source radio frequency 51, can output a power pulse mode. Using pulsed radio frequency power feeding can effectively reduce ion concentration: since the generation and annihilation rate of ions is much faster than that of free radicals, ions are unlikely to form a stable concentration accumulation in pulse mode, while free radicals can continue to diffuse into the substrate region. Furthermore, methods such as reducing the pulse duty cycle and increasing the pulse frequency can further highlight this effect and suppress the stable existence of ion numbers.

[0115] In one embodiment, the pulse frequency of the power pulse mode is not less than 100 Hz to improve the radical / ion production ratio.

[0116] In another embodiment of this application, such as Figure 1 As shown, the radio frequency coil includes a first coil structure 61 and a second coil structure 62. The first coil structure 61 is disposed outside the axial projection of the base 30 in the process chamber 10, and the second coil structure 62 is at least partially disposed within the axial projection of the base 30 in the process chamber 10. In the first process, the second coil structure 62 has no power output or outputs in a power pulse mode, and the average power output of the second coil structure 62 is less than the average power output of the first coil structure 61.

[0117] Considering the plasma activation mode of the RF coil, whether it is inductively coupled plasma (ICP) or transformer-coupled plasma (TCP), the high-energy region of RF energy in the process chamber 10 is located directly below the coil, exhibiting high plasma density and a large number of excited active particles. Conversely, the center of the coil is generally a low-energy region, exhibiting low plasma density or even incomplete activation, with fewer active particles, resulting in a non-uniform distribution. Although the diffusion effect of active particles can mitigate the difference in non-uniform distribution to some extent, the overall trend remains unchanged. Furthermore, due to the continuous suction of the vacuum pump, the overall gas movement direction within the chamber is towards the vacuum pump. This, combined with the fact that the lifetime of free radicals is generally longer than that of ions, and ions annihilate after being neutralized by collisional charges, means that when the plasma excitation region is located at the edge region far from the axis of the process chamber 10, free radicals can reach the substrate region through diffusion, while ions have difficulty reaching it. Based on this, through the above scheme, in the first process stage, plasma excitation is mainly accomplished by the first coil structure 61 at the edge. The first coil structure 61 generates high-density plasma in the edge region of the process chamber 10, exciting the first process gas to produce a large number of active free radicals. These active free radicals move from the edge region to the center region through diffusion, reaching the entire surface of the substrate, and react chemically with the material to be treated, thus carrying out the first process based on free radical reaction.

[0118] The centrally located second coil structure 62 operates with a lower average power, resulting in a lower plasma density in the central region of the process chamber 10. This lower plasma density in the central region reduces the average electron temperature and average ion concentration of the plasma. This suppresses ion bombardment of the substrate, effectively preventing the substrate from undergoing a pure free radical reaction that transforms into reactive ion etching (RIE), eliminating the need for an RPS or grid structure above the substrate, reducing particulate contamination, and improving process efficiency.

[0119] The source radio frequency includes a first source radio frequency 51 and a second source radio frequency 53. The first source radio frequency 51 is connected to a first coil structure 61, and the second source radio frequency 53 is connected to a second coil structure 62. The second coil structure 62 feeds the radio frequency energy output from the second source radio frequency 53 into the process chamber 10; the first coil structure 61 is used to feed the radio frequency energy output from the first source radio frequency 51 into the process chamber 10.

[0120] In one embodiment, such as Figure 1 As shown, the air intake structure is an edge air intake structure 40. Correspondingly, an edge air intake port is located on the side wall of the process chamber 10. Through the edge air intake port, the edge air intake structure 40 introduces the first process gas into the process chamber 10. The plasma processing equipment also includes a central air intake structure. Correspondingly, a central air intake port is provided on the dielectric window 20. Through the central air intake port, the central air intake structure introduces the second process gas into the process chamber 10.

[0121] When process chamber 10 is operating in the first process: The operating modes of the first coil structure 61 and the second coil structure 62 can be any of the following: (1) The second coil structure 62 has no power output: only the first source RF 51 outputs the first pulse power to the first coil structure 61, and the second source RF 53 does not output RF voltage to the second coil structure 62, that is, the second coil structure 62 has no power output, and only the first coil structure 61 outputs pulse power, that is, the first coil structure 61 outputs power pulse mode, and the second coil structure 62 has no power output. The first coil structure 61 feeds the energy output by the first source RF 51 into the process chamber 10. (2) The first source RF 51 outputs the first pulse power to the first coil structure 61, and the second source RF 53 outputs the second pulse power to the second coil structure 62. The first coil structure 61 feeds the energy corresponding to the first pulse power into the process chamber 10, and the average pulse power of the output fed into the process chamber 10 is the first power output. The second coil structure 62 feeds the energy corresponding to the second pulse power into the process chamber 10. The average pulse power of the output fed into the process chamber 10 is the second power output, and the second power output is less than the first power output.

[0122] The working mode of the air intake structure is as follows: (1) The edge air intake structure 40 inputs the first process gas into the process chamber 10.

[0123] The gas in the process chamber 10 is ionized by the corresponding radio frequency energy through the first coil structure 61 or the second coil structure 62 and the first coil structure 61, generating plasma in the process chamber 10. The plasma density is highest below the first coil structure 61. Since it is an edge gas inlet, the plasma excitation region is located in the edge region upstream of the substrate, and the diffusion direction of active particles is generally biased towards the substrate.

[0124] When the first control circuit 8 operates in the first operating mode (i.e., outputting a negative voltage or making the first conductive structure float), the first conductive structure 70 acquires a negative potential. The plasma in the region corresponding to the first coil structure 61 within the process chamber 10 is close to the first conductive structure 70. Therefore, the positive ions in the plasma in the region corresponding to the first coil structure 61 are attracted by the first conductive structure 70, guiding the ions to deviate from the gas inlet direction and accelerate towards the first conductive structure 70. This reduces ion diffusion towards the substrate, and some ions, after being attracted, collide with the first conductive structure 70 and annihilate, thus rapidly dissipating. Meanwhile, free radicals are less affected by the first conductive structure 70 and deviate from the gas inlet direction, easily diffusing along the gas inlet direction to the substrate processing area Q. Ultimately, the substrate modification is completed through the chemical reaction between the free radicals and the substrate surface, forming a modified layer. This avoids the ion degradation modification process from deteriorating into reactive ion etching.

[0125] In one embodiment, the pulse frequency of the first coil structure 61 when outputting in power pulse mode is not less than 100Hz, so as to improve the free radical / ion production ratio.

[0126] When process chamber 10 is operating in the second process: The operating modes of the first coil structure 61 and the second coil structure 62 can be any of the following: (1) Only the second source RF 53 outputs the fourth pulse power to the second coil structure 62. The second coil structure 62 feeds the RF energy output by the second source RF 53 into the process chamber 10. (2) The first source RF 51 outputs the third pulse power to the first coil structure 61, and the second source RF 53 outputs the fourth pulse power to the second coil structure 62. The first coil structure 61 feeds the energy corresponding to the third pulse power into the process chamber 10, and the average pulse power of the output fed into the process chamber 10 is the third power output. The second coil structure 62 feeds the energy corresponding to the fourth pulse power into the process chamber 10, and the average pulse power of the output fed into the process chamber 10 is the fourth power output, and the third power output is less than the fourth power output. The second coil structure 62 and the first coil structure 61 respectively feed the RF energy output by the second source RF 53 and the RF energy output by the first source RF 51 into the process chamber 10.

[0127] In one embodiment, the central intake structure introduces a second process gas into the process chamber 10. This places the plasma excitation region within the substrate processing region, facilitating ion-based processes and reducing the negative impact of the first conductive structure 70.

[0128] In one embodiment, the edge intake structure 40 introduces a second process gas into the process chamber 10.

[0129] The gas inside the process chamber 10 is ionized by the corresponding radio frequency energy through the second coil structure 62 and / or the first coil structure 61, generating plasma in the region corresponding to the coil inside the process chamber 10.

[0130] At this time, when the first control circuit 8 operates in the second operating mode (e.g., the first control circuit 8 outputs a positive voltage), the first conductive structure 70 acquires a positive potential; or when the first control circuit 8 operates in the second operating mode (e.g., grounded), the first conductive structure 70 is grounded. In this state, the first conductive structure 70 is in the second state (e.g., positive potential or grounded), suppressing the formation of a plasma sheath layer on the first conductive structure 70, thus minimizing the influence of the first conductive structure 70 on ions. This increases the ion concentration in the substrate processing region Q, improving the efficiency and quality of ion reactions such as the modified layer stripping process.

[0131] Exemplary control method As a second aspect of this application, this application also provides a method for controlling the ion concentration in a substrate processing region, applicable to the aforementioned plasma processing equipment, wherein, as... Figure 15 As shown, the method for controlling the ion concentration in the substrate treatment region includes the following steps: S1: Provides a process chamber with a first conductive structure located outside the substrate processing area.

[0132] S2: Control the process chamber to operate in a free radical-based first process, control the edge air inlet to blow the first process gas toward the substrate processing area; control the source radio frequency to feed radio frequency energy into the first coil structure located outside the axial projection of the base to excite the first process gas into plasma on the upstream side of the substrate processing area; control the first conductive structure to be in a first state, the first state including a negative potential or to make the first conductive structure in a floating state to attract positive ions on the upstream side of the substrate processing area.

[0133] For example, the first process can be substrate modification, in which free radicals participate in a chemical reaction to form a modified layer on the surface of the substrate to be treated 90, thereby achieving surface modification.

[0134] Combination Figures 1-14As shown, the edge inlet structure 40 blows the first process gas into the process chamber 10 through the edge inlet. Under the excitation of radio frequency energy, this first process gas forms plasma upstream of the substrate processing region Q. The first conductive structure 70 is in a first state (e.g., negative potential). Positive ions in the plasma upstream of the substrate processing region Q are attracted by the first conductive structure 70, guiding them to deviate from the inlet direction and accelerate towards the first conductive structure 70. This reduces ion diffusion towards the substrate, and some ions, after attraction, collide with the first conductive structure 70 and annihilate, thus rapidly dissipating. Free radicals, however, are less affected by the first conductive structure 70 and deviate from the inlet direction, easily diffusing along the inlet direction to the substrate processing region Q. Ultimately, free radicals react chemically with the surface of the substrate 90 to complete substrate modification, forming a modified layer. This avoids the ion degradation modification process from deteriorating into reactive ion etching.

[0135] Similarly, when the first conductive structure 70 is in the floating state of the first state, the floating of the first conductive structure 70 allows electrons to collide with its surface and accumulate to form a plasma sheath. It can also attract positive ions from the plasma upstream of the substrate processing region Q, guiding the ions to deviate from the gas inlet direction and accelerate towards the first conductive structure 70. This reduces ion diffusion towards the substrate, and some ions, after being attracted, collide with the first conductive structure 70 and annihilate, resulting in rapid loss. Free radicals are less affected by the first conductive structure 70 and are less likely to deviate from the gas inlet direction, easily diffusing along the gas inlet direction to the substrate processing region Q. Ultimately, substrate modification is achieved through a chemical reaction between free radicals and the surface of the substrate 90 to be treated, forming a modified layer. This avoids the ion degradation modification process from deteriorating into reactive ion etching.

[0136] In one embodiment of this application, after S2, as Figure 16 As shown, the method for controlling the ion concentration in the substrate processing region provided in this application further includes the following steps: S3: Operate the process chamber in at least an ion-based second process, supply a second process gas to the substrate processing area, control the source radio frequency to feed radio frequency energy into the radio frequency coil to excite the second process gas into plasma, and control the first conductive structure to switch to a second state, the second state including a positive potential or a ground state.

[0137] The second process is a modified layer stripping process, which bombards the material on the surface of the substrate 90 to remove the modified layer. During this process, when the process chamber 10 is operating in the second process mode, the edge air intake structure blows the second process gas into the substrate processing region Q within the process chamber 10 through the edge air intake port. Simultaneously, the source radio frequency feeds radio frequency energy into the radio frequency coil, and the second process gas, under the excitation of the radio frequency energy, forms plasma upstream of the substrate processing region Q. The first conductive structure 70 is in a second state (e.g., positive potential or grounded), suppressing the formation of a plasma sheath on the first conductive structure 70, thus minimizing the influence of the first conductive structure 70 on ions. This increases the ion concentration in the substrate processing region Q, ensuring stripping efficiency and quality.

[0138] In one embodiment, in the first process, the first coil structure 61 outputs a power pulse mode. That is, the first source radio frequency 51 outputs pulse power to the first coil structure 61, and the first coil structure 61, driven by the first source radio frequency 51, can output a power pulse mode. In one embodiment, the pulse frequency of the power pulse mode is not less than 100Hz to improve the free radical / ion production ratio.

[0139] In one embodiment, such as Figure 1 As shown, the RF coil includes a first coil structure 61 and a second coil structure 62. The first coil structure 61 is disposed outside the axial projection of the base 30 into the process chamber 10, and the second coil structure 62 is at least partially disposed within the axial projection of the base 30 into the process chamber 10. The source RF includes a first source RF 51 and a second source RF 53. The first source RF 51 is connected to the first coil structure 61, and the second source RF 53 is connected to the second coil structure 62. The second coil structure 62 feeds the RF energy output from the second source RF 53 into the process chamber 10; the first coil structure 61 is used to feed the RF energy output from the first source RF 51 into the process chamber 10.

[0140] Correspondingly, when the control process chamber 10 is operating in the first process, the substrate processing region ion concentration control method provided in this application further includes the following steps: S20: Control the second coil structure 62 to have no power output or to output in power pulse mode, and the average power output of the second coil structure 62 is less than the average power output of the first coil structure 61.

[0141] When the process chamber 10 is operating in the first process, the operating mode for controlling the first coil structure 61 and the second coil structure 62 can be any of the following: (1) The first source RF 51 outputs a first pulse power to the first coil structure 61, while the second source RF 53 outputs no RF voltage to the second coil structure 62. That is, the second coil structure 62 has no power output, and only the first coil structure 61 outputs pulse power. In other words, the first coil structure 61 outputs power pulse mode, and the second coil structure 62 has no power output. The first coil structure 61 feeds the energy output by the first source RF 51 into the process chamber 10.

[0142] (2) The first source RF 51 outputs a first pulse power to the first coil structure 61, and the second source RF 53 outputs a second pulse power to the second coil structure 62. The first coil structure 61 feeds the energy corresponding to the first pulse power into the process chamber 10, and the average pulse power of the output fed into the process chamber 10 is the first power output. The second coil structure 62 feeds the energy corresponding to the second pulse power into the process chamber 10, and the average pulse power of the output fed into the process chamber 10 is the second power output, and the second power output is less than the first power output.

[0143] At the same time, when the process chamber 10 is operating in the first process, the control edge air intake structure 40 inputs the first process gas into the process chamber 10.

[0144] The gas in the process chamber 10 is ionized by the corresponding radio frequency energy through the first coil structure 61, or the second coil structure 62 and the first coil structure 61, generating plasma in the process chamber 10. The plasma density is highest below the first coil structure 61. Since it is an edge gas inlet, the plasma excitation region is located in the edge region upstream of the substrate, and the diffusion direction of active particles is generally biased towards the substrate.

[0145] When the first control circuit 8 operates in the first operating mode (i.e., outputting a negative voltage or making the first conductive structure float), the first conductive structure 70 acquires a negative potential. The plasma in the region corresponding to the first coil structure 61 within the process chamber 10 is close to the first conductive structure 70. Therefore, the positive ions in the plasma in the region corresponding to the first coil structure 61 are attracted by the first conductive structure 70, guiding the ions to deviate from the gas inlet direction and accelerate towards the first conductive structure 70. On the one hand, this reduces the diffusion of ions towards the substrate; on the other hand, some ions are attracted and collide with the first conductive structure 70, resulting in annihilation and rapid loss. Free radicals are not easily affected by the first conductive structure 70 and deviate from the gas inlet direction, easily diffusing along the gas inlet direction to the substrate processing area Q. Finally, the free radicals react chemically with the surface of the substrate to be processed to complete the substrate modification, forming a modified layer. This avoids the ion degradation modification process from deteriorating into reactive ion etching.

[0146] In one embodiment, the pulse frequency of the first coil structure 61 when outputting in power pulse mode is not less than 100Hz, so as to improve the free radical / ion production ratio.

[0147] After the first process is completed, the operating mode of the control process chamber 10 is switched to the second process.

[0148] In another embodiment of this application, as described in the plasma processing equipment above, the state of the first conductive structure 70 can be controlled by corresponding control circuits (e.g., the first control circuit 8, the third control circuit 83, and the fourth control circuit 84). Therefore, when the process chamber 10 is operating in the first process, the specific control method for "controlling the first conductive structure to be in the first state" in S2 can be: S21: Control the operating mode of the corresponding control circuit to the first mode, that is, output a negative voltage or make the first conductive structure float, thereby controlling the first conductive structure to be in the first state. Similarly, when the process chamber 10 is operating in the second process, the specific control method for "controlling the first conductive structure to be in the second state" in S3 can be: S31: Control the operating mode of the corresponding control circuit to the second mode, that is, output a positive voltage or make the first conductive structure grounded.

[0149] It should be noted that different control circuits have different specific circuit structures, and therefore different control methods. The following explanation uses "controlling the state of the first conductive structure through the first control circuit" as an example: The structure of the first control circuit 8 is as follows: Figure 1 The first control circuit 8 is shown in the figure. The first control circuit 8 includes: a first power supply 81 and a first switch K1; one end of the first switch K1 is connected to the first conductive structure 70, and the other end of the first switch K1 is connected to the first power supply 81. When the process chamber 10 is running in the first process, the first switch K1 is closed and the first power supply 81 is controlled to output a negative voltage so that the first control circuit 8 operates in the first mode, that is, outputs a negative voltage so that the first conductive structure 70 is at a negative potential. When the process chamber 10 is running in the second process, the first switch K1 is closed and the first power supply 81 is controlled to output a positive voltage, so that the first control circuit 8 operates in the second mode, so that the first conductive structure 70 is at a positive potential.

[0150] Similarly, the state of the first conductive structure 70 is controlled by the first control circuit 8 and the fourth control circuit 84 (the structure of the plasma processing equipment is as follows). Figure 12 As shown), the state of the first conductive structure 70 is controlled by the third control circuit 83 (the structure of the plasma processing device is as shown). Figure 13As shown), the state of the first conductive structure 70 is controlled by the third control circuit 83 and the fourth control circuit 84 (the structure of the plasma processing device is as shown). Figure 14 As shown), when the process chamber 10 operates in the first process and the second process, the specific control principle of the corresponding control circuit is the same as the working principle of the first control circuit 8 described above, and will not be repeated here. In one embodiment of this application, in addition to the first conductive structure 70, the plasma processing device also includes a second conductive structure 76 and a second control circuit 80. The second control circuit 80 is connected to the second conductive structure 76, as shown below. Figure 6 as well as Figure 1 As shown.

[0151] Correspondingly, when the process chamber 10 is operating in the first process, the second control circuit 80 is also controlled to operate in the first mode, that is, outputting a negative voltage or making the second conductive structure float to ground, so as to control the second conductive structure 76 to obtain a negative potential or to make the second conductive structure float to attract positive ions in the plasma; when the process chamber 10 is operating in the second process, the second control circuit 80 is controlled to operate in the second mode, that is, outputting a positive voltage or making the second conductive structure ground, so as to control the second conductive structure 76 to obtain a positive potential or to make the second conductive structure ground. Its working principle is the same as the working mode of the first control circuit 8 to regulate the potential of the first conductive structure 70, and will not be described in detail here.

[0152] Similarly, different structures of the second control circuit 80 result in different control methods for controlling the operating mode of the second control circuit 80. Figure 6 Taking the second control circuit 80 shown as an example: like Figure 6 As shown, the second control circuit 80 includes a second power supply 82 and a third switch K3. One end of the third switch K3 is connected to the second power supply 82, and the other end of the third switch K3 is connected to the second conductive structure 76. When the process chamber 10 is running in the first process, the second power supply 82 is controlled to output a negative voltage, and the third switch K3 is controlled to close. The second control circuit 80 outputs a negative voltage, and the second conductive structure 76 is in a negative state.

[0153] When the process chamber 10 is running in the second process, the second power supply 82 is controlled to output a positive voltage and the third switch K3 is controlled to close. The second control circuit 80 outputs a positive voltage and the second conductive structure 76 is positively charged.

[0154] Semiconductor process equipment As a third aspect of this application, this application also provides a semiconductor process apparatus, including: the above-mentioned plasma processing apparatus and a controller; The controller is used to execute the above-mentioned method for regulating the ion concentration in the substrate processing area.

[0155] For example, the controller includes a processor and a memory, in which a computer program is stored. When the processor executes the computer program, it performs the aforementioned method for controlling the ion concentration in the substrate processing region.

[0156] The embodiments described above are merely illustrative of several implementation methods outlined in this specification. While the descriptions are specific and detailed, they should not be construed as limiting the scope of the solutions provided in this specification. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this specification, and these all fall within the scope of protection of this specification. Therefore, the scope of protection for this patent should be determined by the appended claims.

Claims

1. A plasma processing apparatus, comprising a process chamber sealed by a dielectric window, wherein a base is disposed therein for supporting a substrate to be processed. A radio frequency (RF) coil is disposed outside the dielectric window. The RF coil is electrically connected to an active RF source to feed RF energy into the process chamber. The process chamber has an exhaust port for communication with a vacuum pumping assembly, characterized in that... The process chamber includes a substrate processing area, which is located above the axial projection of the base. The process chamber is provided with an edge air inlet at its radial edge; The radio frequency coil includes a first coil structure disposed outside the axial projection of the base. A first conductive structure is disposed within the process chamber, and the first conductive structure is located outside the substrate processing area. The edge air inlet is configured to blow a first process gas toward the substrate processing area; The source radio frequency is configured to feed radio frequency energy into the first coil structure to excite the first process gas into plasma on the upstream side of the substrate processing region; The first conductive structure is configured to be in a first state when the process chamber is operating a radical-based first process, the first state including a negative potential or a floating state of the first conductive structure to attract positive ions upstream of the substrate processing region.

2. The plasma processing equipment according to claim 1, characterized in that, When the process chamber is operating at least an ion-based second process, the first conductive structure switches to a second state, which includes a positive potential or a grounded state.

3. The plasma processing apparatus according to claim 1 or 2, characterized in that, Also includes: A first control circuit is connected to the first conductive structure. When the process chamber is operating in the first process, the first control circuit operates in a first operating mode, which includes outputting a negative voltage or making the first conductive structure float to ground, so that the first conductive structure is in the first state.

4. The plasma processing equipment according to claim 3, characterized in that, When the process chamber is operating in a second process based at least on ions, the first control circuit operates in a second operating mode, which includes outputting a positive voltage or grounding the first conductive structure so that the first conductive structure is in a second state.

5. The plasma processing apparatus according to claim 3, characterized in that, The first control circuit includes: a first power supply, which can selectively output a positive pulse voltage or a negative pulse voltage; and a first switch, which controls the connection or disconnection between the first conductive structure and the first power supply; and / or The first control circuit includes a second switch, which controls the first conductive structure to be grounded or floating.

6. The plasma processing apparatus according to claim 1 or 2, characterized in that, It also includes a third control circuit for controlling whether the base is grounded or floating. The first conductive structure is disposed on the outer periphery of the side of the base and is electrically connected to the base.

7. The plasma processing apparatus according to claim 3, characterized in that, The first conductive structure is insulated and fixed to the outer periphery of the side of the base. The first conductive structure and the base are electrically connected in a switchable manner through the first control circuit. The base is grounded.

8. The plasma processing apparatus according to claim 6, characterized in that, The first conductive structure is configured as the lining of the process chamber. The first end of the lining is insulated and fixed to the side wall of the process chamber and electrically connected to it via a fourth control circuit. The second end of the lining is electrically connected to the base. The fourth control circuit is switched on and off synchronously with the third control circuit.

9. The plasma processing apparatus according to claim 7, characterized in that, The first conductive structure is configured as the liner of the process chamber. The first end of the liner is insulated and fixed to the side wall of the process chamber and electrically connected to it in a switchable manner through a fourth control circuit. The second end of the liner is insulated and fixed to the base and electrically connected to it in a switchable manner through the first control circuit. The fourth control circuit is switched on and off synchronously with the first control circuit.

10. The plasma processing apparatus according to claim 1, characterized in that, It also includes a bias power supply, which is electrically connected to the base and is used to apply a bias voltage to the substrate. In the first process, the bias power supply is either in a closed state or substantially at a positive potential.

11. The plasma processing apparatus according to claim 1 or 2, characterized in that, The first conductive structure is disposed between the edge air inlet and the exhaust outlet, such that when the first conductive structure is in the first state, the positive ions on the upstream side of the substrate processing area are deflected towards the direction of the exhaust outlet.

12. The plasma processing apparatus according to claim 3, characterized in that, The first conductive structure includes a first conductive portion located between the substrate processing region and the axial projection region of the first coil structure, and the first process gas flows through the first conductive portion to reach the substrate processing region.

13. The plasma processing apparatus according to claim 12, characterized in that, The first conductive structure includes a second conductive portion located on the side of the base, and the flow resistance of the first conductive portion is less than the flow resistance of the second conductive portion.

14. The plasma processing apparatus according to claim 1, characterized in that, The substrate to be processed does not have a grid structure directly above it, which is used to reduce the flow of ions to the substrate.

15. The plasma processing apparatus according to claim 1, characterized in that, The maximum distance from the dielectric window to the top surface of the base is less than 1 / 4 of the maximum inner diameter of the side wall of the process chamber.

16. The plasma processing apparatus according to claim 1, characterized in that, The radio frequency coil includes a second coil structure that is at least partially disposed within the axial projection of the base. In the first process, the second coil structure has no power output or outputs in a power pulse mode, and the average power output of the second coil structure is less than the average power output of the first coil structure.

17. A method for controlling the ion concentration in a substrate processing region, characterized in that, Applied to the plasma processing apparatus as described in claim 1, wherein, A process chamber is provided having a first conductive structure located outside the substrate processing region. The process chamber is operated in a free radical-based first process, and the edge air inlet is controlled to blow the first process gas toward the substrate processing area. The control source feeds radio frequency energy into the first coil structure located outside the axial projection of the base to excite the first process gas into plasma on the upstream side of the substrate processing region; The first conductive structure is controlled to be in a first state, which includes a negative potential or a floating state, so as to attract positive ions on the upstream side of the substrate processing region.

18. The control method according to claim 17, characterized in that, The process chamber is operated in a second process based on at least ions, and the first conductive structure is controlled to switch to a second state, which includes a positive potential or a grounded state.

19. The control method according to claim 17, characterized in that, In the first process, the output of the first coil structure is a power pulse mode.

20. The control method according to claim 17, characterized in that, The process chamber is operated in a second process based at least on ions, and a second process gas is supplied to the substrate processing region. The control source feeds radio frequency energy into the radio frequency coil to excite the second process gas into plasma; The first conductive structure is controlled to be in a second state, which includes a positive potential or a grounded state.

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