An apparatus for improving plasma activation uniformity of a wafer based on dynamic assistance

Abstract

The application provides a device for improving wafer plasma activation uniformity based on dynamic assistance, and belongs to the technical field of semiconductor manufacturing processes.The device comprises the following contents: a rotating table is arranged, a wafer is placed on the top of the rotating table, and the wafer is used for rotating in a process gas flow field; a boundary disturbance device is arranged outside the rotating table and is arranged in a gap from the rotating table, and the boundary disturbance device is fixedly arranged relative to the rotating table; a conical hollow flow guide is arranged above the rotating table and is fixedly arranged relative to the rotating table, one end of the conical hollow flow guide is communicated with an air inlet, and the other end of the conical hollow flow guide is connected with the boundary disturbance device; a sieve flow uniform distribution layer is arranged on one side of the rotating table away from the conical hollow flow guide and is fixedly arranged relative to the rotating table, a plurality of through holes are arranged on the sieve flow uniform distribution layer and are arranged in penetration along a radial direction of the wafer; and an air flow stabilizing cavity is arranged on one side of the sieve flow uniform distribution layer away from the rotating table.

Description

Technical Field

[0001] This invention relates to the field of semiconductor manufacturing process technology, and in particular to a device for improving the uniformity of wafer plasma activation based on dynamic assistance. Background Technology

[0002] As the fundamental carrier in semiconductor device manufacturing, wafers are widely used in integrated circuits, microelectromechanical systems (MEMS), power devices, optoelectronic devices, and various sensors. With the development of advanced packaging, 3D integration, and heterogeneous integration technologies, high-quality bonding between wafers of different materials has become a critical process in semiconductor manufacturing. Common wafer materials include single-crystal silicon (Si), silicon carbide (SiC), gallium arsenide (GaAs), and indium phosphide (InP). These wafers typically have stringent requirements for surface flatness, thickness uniformity, and dimensional tolerances to meet the process requirements of micro / nano-scale structure fabrication and multilayer integration.

[0003] In wafer bonding processes, the quality of the bonding interface directly affects the mechanical strength, electrical performance, and long-term reliability of the device. Therefore, pretreatment of the wafer surface is usually required before bonding to improve surface activity and interfacial bonding ability. Existing technologies typically include chemical cleaning, plasma surface activation, and drying. Among these, plasma surface activation technology has been widely used in wafer bonding pretreatment processes due to its advantages such as low processing temperature, strong reaction controllability, and wide material adaptability. Existing plasma activation equipment usually adopts a vertical gas injection structure, where process gas is introduced from the top or above the plasma reaction chamber and excited to form plasma under the action of a radio frequency or microwave electric field. The gas flow direction is basically perpendicular to the wafer surface. In this structure, the gas tends to concentrate at a high velocity in the central region of the wafer, making the central region a region with high plasma density and high reactivity. Meanwhile, the edge regions of the wafer suffer from insufficient gas supply or flow field attenuation, resulting in a relatively weak plasma activation effect and thus forming a significant radial non-uniform distribution on the wafer surface.

[0004] Some literature discloses that a porous sieve plate or diffuser plate is set between the gas inlet and the wafer to initially disperse the process gas entering the cavity. The above devices can improve the overall activation effect of the wafer surface to a certain extent. However, since the gas still mainly impacts the central region of the wafer in the vertical direction, the gas is still easily affected by local flow field disturbances during the radial diffusion process on the wafer surface. The difference in plasma treatment intensity between the wafer center and the edge is still difficult to completely eliminate.

[0005] Therefore, it is essential to provide a device for improving the uniformity of wafer plasma activation based on dynamic assistance. This device can optimize the dynamic support method and gas transport path design of the wafer without changing the main structure of the existing plasma reaction chamber, so that the process gas can diffuse rapidly and uniformly in the radial and circumferential directions after acting on the wafer surface. This effectively improves the uniformity of wafer surface plasma activation and process stability, and meets the ever-increasing application requirements of high-reliability wafer bonding processes. Summary of the Invention

[0006] In view of this, the present invention proposes a device for improving the uniformity of wafer plasma activation based on dynamic assistance, without modifying the existing plasma cavity structure, to further improve the lateral diffusion capability of process gas on the wafer surface and ensure the equivalence and consistency of plasma activation throughout the entire wafer.

[0007] This invention provides a device for improving the uniformity of wafer plasma activation based on dynamic assistance, comprising the following components: A rotating stage is configured, with the wafer placed on top of the rotating stage to drive the wafer to rotate in the process gas flow field; A boundary disturbance device is arranged around the outside of the rotating stage and is spaced apart from the rotating stage. The boundary disturbance device is fixed relative to the rotating stage and is used to generate a micro-disturbance effect on the passing process gas and adjust the distribution of process gas at the edge of the wafer. A conical hollow flow guide is set above the rotating stage and fixed relative to the rotating stage. One end is connected to the air inlet and the other end is connected to the boundary turbulence device. It is used to guide the process gas to slide and diffuse along the conical cross section and flow to different positions on the wafer surface. The flow distribution layer is located on the side of the rotating stage away from the conical hollow guide and is fixed relative to the rotating stage. The flow distribution layer has several through holes, which are arranged along the radial direction of the wafer. These through holes are used to weaken the axial jet of process gas and improve the radial distribution of process gas. A gas flow stabilizing cavity is located on the side of the flow distribution layer away from the rotating stage. The gas flow stabilizing cavity is used to form a buffer zone to suppress the local jet residue effect.

[0008] Based on the above technical solutions, preferably, the rotating shaft of the rotating stage is connected to the servo motor for transmission. The servo motor is located on the side of the sieve flow distribution layer away from the conical hollow guide. An electromagnetic shielding protection mechanism is provided on the outside of the servo motor, and the electromagnetic shielding protection mechanism is arranged around the servo motor to isolate electromagnetic interference. A flexible vibration damping component is also provided on the side of the electromagnetic shielding protection mechanism away from the rotating stage to absorb the instantaneous impact force generated when the servo motor starts and brakes, so that the wafer maintains positional stability during the activation process.

[0009] Preferably, the natural frequency of the flexible vibration damping component f n With drive frequency f d The following relationship must be satisfied: , , k For the stiffness of the flexible vibration damping component, m The total mass of the rotating stage and the wafer. For frequency security threshold, f n ≤0.5 f d or f n ≥2 f d The stiffness of the flexible vibration damping components is adjustable.

[0010] Preferably, the angular velocity of the rotating stage ω satisfy The rotating platform is equipped with flexible positioning grooves and arc-shaped guide rails to provide radial constraint stiffness for the wafer. k r Not less than the minimum constraint stiffness required to prevent slippage of the wafer relative to the rotating stage k min .

[0011] Based on the above technical solutions, preferably, the diameter of the conical hollow flow guide near the wafer end is larger than the diameter away from the wafer end, and the included angle of the conical surface of the central cross-section of the conical hollow flow guide is... θ satisfy The average value of the inner diameter of the conical hollow guide D g With wafer diameter D w The following relationship must be satisfied: .

[0012] Based on the above technical solutions, preferably, the surface of the boundary turbulence device is provided with multiple sets of turbulence prisms, which are used to generate a micro-turbulence effect on the airflow passing through the boundary; the gap between the boundary turbulence device and the rotating platform is adjustable.

[0013] Based on the above technical solutions, preferably, the equivalent pore diameter per unit area of ​​the through holes on the sieve flow distribution layer is... d ( r ) and pore density per unit area n ( r The projection position of the via relative to the wafer center on the sieve flow distribution layer. r related, , , , R The effective radius of the uniformly distributed sieve layer. d (0) and n (0) represents the equivalent pore diameter per unit area and the pore density per unit area of ​​the projected position of the wafer center on the sieve flow distribution layer, respectively, and the open area ratio of the through-hole is... .

[0014] Preferably, the center-to-center distance between adjacent through holes on the sieve flow distribution layer is... P ( r The equivalent aperture per unit area at the location of the through hole. d ( r The following relationship is satisfied: .

[0015] Preferably, the height of the airflow stabilizing cavity H Average pore size per unit area of ​​the through-holes in the uniformly distributed sieve layer The following relationship must be satisfied: .

[0016] Preferably, the device also includes a housing, with an air inlet at the top and an air outlet at the bottom. A device placement platform is located inside the housing, with several through channels on the platform. The placement platform is used to place flexible vibration damping components and defines the current position of the sieve flow distribution layer. An airflow stabilization cavity is formed between the placement platform and the sieve flow distribution layer, and the channels connect the airflow stabilization cavity to the air outlet. The rotating platform, boundary flow disturbance device, and conical hollow guide are all located inside the housing, and the output shaft of the servo motor passes through the electromagnetic shielding protection mechanism and the sieve flow distribution layer, and is connected to the rotating platform via a transmission connection.

[0017] The present invention provides a device for improving the uniformity of wafer plasma activation based on dynamic assistance, which has the following advantages compared with the prior art: 1. By using a rotating stage in conjunction with a boundary flow deflector and a conical hollow flow guide, the process gas can be guided to slide and diffuse through the conical interface, significantly improving the uniform distribution of the process gas on the wafer surface, thereby enhancing the uniformity of plasma activation. The introduction of angular velocity limitation of the rotating stage and the design of flexible positioning grooves can ensure the radial constraint of the wafer during processing, ensuring that it does not slip and improving processing accuracy. The deflection prisms set on the surface of the boundary flow deflector can generate multiple micro-disturbances on the airflow, thereby enhancing the airflow mixing effect and further improving the gas distribution.

[0018] 2. The through-hole setting of the sieve flow uniform distribution layer can weaken the axial process gas jet, improve the radial distribution, reduce the residual effect of local jets, and form a more uniform airflow field. The through-hole design on the sieve flow uniform distribution layer can accurately control the equivalent aperture and pore density per unit area according to the projection position of the wafer center, providing more flexible airflow adjustment capability.

[0019] 3. By combining servo motors and flexible vibration damping components, the instantaneous impact force generated during startup and braking can be effectively absorbed, maintaining the positional stability of the wafer during the activation process. The stiffness of the flexible vibration damping components is adjustable, allowing the system to be optimized according to different process requirements and adapt to various working conditions.

[0020] 4. The airflow stabilization chamber forms a buffer zone, further suppressing airflow instability, ensuring a stable supply of process gas, and improving the overall reliability of the process. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention 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 some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a three-dimensional view of the device structure of the apparatus for improving the uniformity of wafer plasma activation based on dynamic assistance according to the present invention; Figure 2 This is a half-section front view of the device for improving the uniformity of wafer plasma activation based on dynamic assistance according to the present invention. Figure 3 This is a top view of the device for improving the uniformity of wafer plasma activation based on dynamic assistance according to the present invention; Figure 4 This is a longitudinal sectional view of the internal structure of the housing of a device for improving the uniformity of wafer plasma activation based on dynamic assistance according to the present invention. Figure 5 This is a schematic diagram of the detection points of a device for improving the uniformity of wafer plasma activation based on dynamic assistance according to the present invention; Figure 6 This is a flowchart of a group control experiment for a device based on dynamic assistance to improve the uniformity of wafer plasma activation according to the present invention.

[0023] Reference numerals: 1. Boundary turbulence device; 2. Filtered flow distribution layer; 3. Rotating platform; 4. Electromagnetic shielding protection mechanism; 5. Servo motor; 6. Flexible vibration damping component; 7. Conical hollow guide; 8. Air inlet; 9. Shell; 10. Device placement platform; 11. Air outlet. Detailed Implementation

[0024] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0025] In existing plasma activation technologies, some improvements attempt to disrupt and average the distribution of process gases on the wafer surface by setting porous sieves or employing wafer rotation mechanisms, thereby improving the macroscopic uniformity of the plasma activation region to some extent. These methods are based on a time-averaging approach, using the wafer's rotation relative to the gas flow to activate it at multiple times and from multiple directions, thus suppressing local over-processing or under-processing. However, these methods still have significant limitations. Since the process gases are typically injected vertically from the top of the cavity, their initial momentum is concentrated in the central region of the wafer, forming an impingement flow, resulting in a significantly higher gas density in this region than at the edges. Even when the wafer is rotating at low speed, the radial diffusion of the gas flow after the impact is constrained by edge perturbation and viscous shear effects, making true radial uniform diffusion difficult to achieve, resulting in a non-uniform plasma distribution with central oversaturation and edge dilution. This surface gas distribution non-uniformity ultimately affects the plasma excitation efficiency, thereby reducing interfacial bonding strength and bonding yield.

[0026] In view of this, such as Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, the present invention provides a device for improving the uniformity of wafer plasma activation based on dynamic assistance, comprising the following components: A rotating stage 3 is configured, with the wafer placed on top of it to drive the wafer to rotate within the process gas flow field. The rotating stage 3 is exposed to the plasma, and its material can be a corrosion-resistant ceramic material, such as anodic alumina, yttrium oxide (Y₂O₃), or high-purity Al₂O₃. This dynamic rotation mechanism exposes the wafer surface to a time-varying gas flow field, thereby improving the uniformity of the processing area on a macroscopic scale through a time-averaging effect, and thus improving the overall uniformity of plasma activation. Here, the process gas is plasma. To drive the rotating stage 3 to rotate at a uniform speed, the rotating shaft of the rotating stage 3 is connected to a servo motor 5, which is located on the side of the sieve flow distribution layer away from the conical hollow guide.

[0027] A boundary disturbance device 1 is arranged around the outside of the rotating stage 3, with a gap between it and the rotating stage 3. The boundary disturbance device 1 is fixed relative to the rotating stage 3 and is used to generate a micro-disturbance effect on the passing process gas, adjusting the distribution of process gas at the wafer edge. The boundary disturbance device 1 is located on the periphery of the rotating stage 3 and does not participate in the rotation. In fluid dynamics, it plays the role of stimulating near-wall disturbance of the airflow, which helps to break up the uneven velocity gradient region caused by the boundary layer viscosity effect. At the same time, the rotation of the stage drives the small-scale flow outside the disturbance ring to enhance the redistribution of gas at the edge, thereby improving the gas activation uniformity of the entire wafer area.

[0028] A conical hollow guide 7 is positioned above and fixed relative to the rotating stage 3. One end is connected to the gas inlet, and the other end is connected to the boundary flow disturbance device 1. It guides the process gas to slide and diffuse along a conical cross-section, flowing to different locations on the wafer surface. To improve the problem of oversaturation at the wafer center and insufficient gas at the edges caused by traditional vertical injection of process gas, this embodiment introduces a central diffusion guiding structure—the conical hollow guide 7. Its structure is an inverted cone with a through-flow gas channel in the middle. The upper end of the conical hollow guide 7 is connected to the process gas source, and the lower end is connected to the boundary flow disturbance device 1 via a locking mechanism. When the process gas passes through the conical hollow guide 7, it effectively avoids the problem of excessively high plasma density caused by gas concentration only in the central region. In this embodiment, the conical hollow guide 7 is made of high-temperature resistant dielectric polyimide composite material, whose good gas affinity and low plasma adsorption make it stable and reliable in a high-frequency discharge environment.

[0029] The flow distribution layer 2 is disposed on the side of the rotating stage 3 away from the conical hollow guide 7 and is fixed relative to the rotating stage 3. The flow distribution layer 2 has several through-holes, which are arranged along the radial direction of the wafer. These through-holes are used to weaken the axial jet of process gas and improve the radial distribution of the process gas. A gas flow stabilizing cavity is disposed on the side of the flow distribution layer 2 away from the rotating stage 3. The gas flow stabilizing cavity forms a buffer zone to suppress local jet residue effects. The flow distribution layer 2 weakens the concentrated jet effect of gas in the axial direction through the distribution of through-holes at different positions. The hole diameter is slightly smaller and denser in the central region, while the hole diameter is appropriately increased in the edge region to match the non-uniformity of the initial velocity distribution of the process gas. By adjusting the hole diameter gradient and through-hole density, macroscopic "homogenization" of the process gas flow rate is achieved, thereby weakening the high-speed axial jet and improving the radial flow distribution. Based on the above-mentioned through-hole distribution design, the sieve flow distribution layer 2 forms multiple micro-scale airflow convergence and dispersion regions during the process gas flow, guiding the process gas to exhibit lateral dispersion behavior. This, in conjunction with the conical hollow guide vane 7, creates flow field conditions for the directional guidance and diffusion of the process gas. The airflow stabilization cavity serves as a short-range buffer zone, enhancing the uniformity and stability of the process gas diffusion.

[0030] It also includes a housing 9, with an air inlet 8 at the top and an air outlet 11 at the bottom. A device placement platform 10 is provided inside the housing 9, and several through channels are provided on the device placement platform 10. The device placement platform 10 is used to place the servo motor 5 and the current position of the sieve flow distribution layer 2 is defined by position limiting structures such as guide pillars. An airflow stabilization cavity is formed between the device placement platform 10 and the sieve flow distribution layer 2, and the channels connect the airflow stabilization cavity to the air outlet 11. The rotating platform 3, the boundary turbulence device 1, and the conical hollow guide 7 are all set inside the housing 9, and the output shaft of the servo motor 5 passes through the sieve flow distribution layer 2 and is connected to the rotating platform 3 for transmission.

[0031] After configuring the above structure, process gas is introduced into the housing 9 to activate the plasma uniformity of the wafer. During operation, high-purity process gas, regulated by a mass flow controller, is injected uniformly into the housing 9 through the inlet 8. Guided by the conical hollow guide 7, it distributes radially and flows towards the upper surface of the wafer, forming an approximately radial annular flow above the wafer. This improves the consistency of the gas residence time at different locations, thereby enhancing the spatial uniformity of the plasma density distribution. During this process, the rotating stage 3 drives the wafer to rotate at a set angular velocity. The originally fixed airflow non-uniformity is dynamically averaged. Even if there are slight density differences in a short period, after a long period of rotation, the overall plasma dose received by the wafer tends to be balanced, achieving dynamic coverage of the process gas on the wafer surface. After the process gas undergoes gas-phase reaction on the wafer surface, it is rectified and further uniformly dispersed by the device placement platform 10 at the bottom of the housing, and finally discharged to the exhaust gas treatment system through the outlet 11 at the bottom of the housing 9. This process not only ensures the uniform distribution and efficient exchange of process gases during wafer surface treatment, but also effectively reduces the local non-uniform plasma effect caused by airflow impacting the wafer center, achieving simultaneous improvement in plasma treatment uniformity and wafer bonding quality.

[0032] The rotating stage 3 structure introduced in this embodiment enables slow rotation of the wafer in a plasma environment, forming a low-speed, quasi-stable radial flow boundary on the wafer surface. This dynamic disturbance mechanism, combined with the boundary disturbance device 1 and the diffusion structure of the conical hollow guide 7, redistributes the process gas before it enters the wafer surface, effectively mitigating problems such as edge disturbance, center accumulation, and localized gas blind zones that are common in conventional processes. Through the synergistic effect of these structures, the gas excitation density exhibits a smoother and more uniform trend along the radial direction of the wafer, achieving superior gas diffusion uniformity and plasma activation consistency compared to traditional non-rotating or non-guided structure schemes.

[0033] In one embodiment, an electromagnetic shielding protection mechanism 4 is provided around the servo motor 5 to isolate electromagnetic interference. A flexible vibration damping component 6 is also provided on the side of the electromagnetic shielding protection mechanism 4 away from the rotating platform 3 to absorb the instantaneous impact force generated during the start-up and braking of the servo motor 5, ensuring the wafer maintains positional stability during the activation process. The electromagnetic shielding protection mechanism 4 is mainly used to isolate the servo motor 5, preventing the radio frequency electromagnetic field generated during plasma discharge from interfering with the motor's operational stability. To ensure the rotational accuracy of the motor shaft, a bearing is typically installed to rotate with it; this bearing is located within the electromagnetic shielding protection mechanism 4. The electromagnetic shielding protection mechanism 4 includes a nickel-plated aluminum alloy metal protective cover and an insulating layer, providing both electrical insulation and thermal shielding capabilities. This multi-layered shielding and buffering effectively isolates high-frequency plasma radiation interference, ensuring the long-term stable operation of the servo motor 5. The flexible vibration damping component 6 can reduce the transmission of minute vibrations generated by the motor under low-speed operating conditions, preventing the wafer from jumping up and down and displacement disturbances, structurally ensuring the relative positional stability between the gas action area and the wafer surface.

[0034] The flexible vibration damping component 6, acting as a buffer mechanism, primarily absorbs the instantaneous impact force generated during motor startup and braking, ensuring the wafer maintains high stability and low micro-fluctuation amplitude throughout the processing. This component is composed of a high-damping silicone layer, elastic gaskets, and a vibration damping frame, and achieves coordinated rigid-flexible control through an adjustable pressure mechanism. To prevent the corrosive effect of plasma, an aluminum oxide layer can be added to the exposed parts of the component for protection. To avoid the adverse effects of mechanical resonance on the stability of the plasma activation process, the natural frequency of the flexible vibration damping component 6 is... f n With drive frequency f d The following relationship must be satisfied: , , k For the stiffness of the flexible vibration damping component 6, m The total mass of the rotating stage 3 and the wafer. For frequency security threshold, f n ≤0.5 f d or f n ≥2 f d The stiffness of the flexible vibration damping component 6 is adjustable. The flexible vibration damping component 6 adopts a "soft-hard" composite stiffness structure; during low-frequency impacts, the soft layer absorbs energy, while during high-frequency micro-vibrations, the hard layer provides support. The compression of the flexible vibration damping component 6 is changed in real time through an adjustable pressure mechanism, such as screw pre-tensioning or air pressure regulation, thereby continuously adjusting the stiffness of the flexible vibration damping component 6. kThe allowable amplitude of micro-motion during wafer rotation. The stiffness of the flexible damping component 6 should typically be less than 1 / 1000 of the wafer feature size. k Need to meet , F max This represents the maximum impact force when the motor starts and stops.

[0035] In one embodiment, the angular velocity of the rotating platform 3 ω satisfy The rotating stage 3 is equipped with flexible positioning grooves and arc-shaped guide rails to enhance the radial constraint stiffness of the wafer. k r Not less than the minimum constraint stiffness that prevents the wafer from slipping relative to the rotating stage 3 k min .

[0036] In another embodiment, the diameter of the conical hollow flow guide 7 near the wafer end is larger than the diameter away from the wafer end, and the included angle of the conical surface of the central cross-section of the conical hollow flow guide 7 is... θ satisfy The average value of the inner diameter of the conical hollow guide 7 D g With wafer diameter D w The following relationship must be satisfied: .

[0037] The boundary flow disturbance device 1 has multiple sets of flow disturbance prisms on its surface. The flow disturbance prisms are used to generate a slight disturbance effect on the airflow passing through the boundary. The gap between the boundary flow disturbance device 1 and the rotating platform 3 is adjustable.

[0038] To achieve macroscopic "homogenization" of process gas flow rate and improve the radial distribution of process gas, the equivalent pore size per unit area of ​​the through holes in the sieve flow distribution layer 2 is... d ( r ) and pore density per unit area n ( r The projection position of the via relative to the wafer center on the sieve flow distribution layer 2 r related, , , , R The effective radius of the uniformly distributed sieve layer 2 is given. d (0) and n (0) represents the equivalent pore size per unit area and the pore density per unit area of ​​the projected position of the wafer center on the sieve flow uniform distribution layer 2, respectively, and the opening rate of the through hole is... The central axes of adjacent through holes on the sieve flow uniform distribution layer 2 are not arranged linearly, but rather in an alternating pattern. The center distance between adjacent through holes on the sieve flow uniform distribution layer 2 is...P ( r The equivalent aperture per unit area at the location of the through hole. d ( r The following relationship is satisfied: .

[0039] In one embodiment, the height of the airflow stabilizing cavity H Average pore size per unit area of ​​the through holes in the uniformly distributed sieve layer 2 The following relationship must be satisfied: .

[0040] The rotating tray of this invention can be connected to an external controller via wireless communication to achieve real-time speed adjustment and fault feedback monitoring. Users can set different speed programs to adapt to various wafer materials and sizes, such as Si, SiC, and GaAs, thereby expanding the system's adaptability and compatibility. To further improve the adaptability and adjustability of the structure in actual cavity operating environments, this invention adopts a modular, detachable, and combinable structural arrangement. The rotating stage is flexibly connected to the shell via a mechanical positioning bracket, which not only facilitates disassembly and maintenance but also allows for quick replacement of rotating stages of different specifications according to wafer size and process requirements, improving process versatility. The conical hollow flow guide 7 and the boundary flow disturbance device 1 are also detachable structures. The above design of this invention not only significantly improves the surface uniformity of plasma processing but also has engineering advantages such as simple structure, easy installation, and low maintenance costs. It is suitable for the retrofitting and upgrading of most existing plasma cavity systems and has practical value for multiple steps such as wafer bonding pretreatment, surface cleaning, and interface reaction enhancement.

[0041] To objectively quantify and verify the effect of the aforementioned dynamic assistance and multi-dimensional flow guiding structure on improving plasma distribution uniformity, and to optimize process parameters accordingly, this invention conducted comparative verification. The verification process is as follows: Figure 6 As shown.

[0042] To accurately assess the spatial distribution uniformity of wafer surface energy, a standardized surface characterization process was performed on the processed wafers, selecting wafers of specific materials and sizes, such as... Figure 5 As shown, multiple measurement points were defined on the wafer surface, divided into experimental and control groups. The experimental group underwent plasma activation treatment using the methods described in this invention. The control group underwent conventional plasma activation treatment without using the methods described in this invention. Contact angle measurements before and after activation were obtained at each point using a contact angle meter. Based on the obtained data, the average value, standard deviation, and coefficient of variation of the contact angle changes were calculated.

[0043] Calculate the change in contact angle at each measurement point. ; The contact angle after the measurement point is activated. The contact angle before activation at the measurement point;i =1,2,..., N , i The sequence number of each measurement point. N This represents the total number of measurement points. Calculate the average value of the change in contact angle ; Calculate the standard deviation of the change in contact angle ; coefficient of variation .

[0044] The contact angle variation range of the experimental group was 9°-12°, while that of the control group was 4°-7°. The coefficient of variation for the experimental group was 9.81%, and that for the control group was 17.04%. By comparing the statistical indicators of the experimental and control groups under the same process conditions but with different plasma activation equipment, especially the significant reduction in the coefficient of variation, the technical effect of this invention in improving activation uniformity can be directly and quantitatively confirmed. This invention is not only used for effect verification; its feedback results can also be used to further fine-tune process parameters such as rotation speed and gas flow rate to achieve process optimization.

[0045] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An apparatus for improving plasma activation uniformity of a wafer based on dynamic assistance, comprising: Includes the following: A rotating stage is configured, with the wafer placed on top of the rotating stage to drive the wafer to rotate in the process gas flow field; A boundary disturbance device is arranged around the outside of the rotating stage and is spaced apart from the rotating stage. The boundary disturbance device is fixed relative to the rotating stage and is used to generate a micro-disturbance effect on the passing process gas and adjust the distribution of process gas at the edge of the wafer. A conical hollow flow guide is set above the rotating stage and fixed relative to the rotating stage. One end is connected to the air inlet and the other end is connected to the boundary turbulence device. It is used to guide the process gas to slide and diffuse along the conical cross section and flow to different positions on the wafer surface. The flow distribution layer is located on the side of the rotating stage away from the conical hollow guide and is fixed relative to the rotating stage. The flow distribution layer has several through holes, which are arranged along the radial direction of the wafer. These through holes are used to weaken the axial jet of process gas and improve the radial distribution of process gas. A gas flow stabilizing cavity is located on the side of the flow distribution layer away from the rotating stage. The gas flow stabilizing cavity is used to form a buffer zone to suppress the local jet residue effect.

2. The apparatus for improving plasma activation uniformity of a wafer based on dynamic assistance according to claim 1, wherein, The rotating stage's shaft is connected to a servo motor. The servo motor is located on the side of the sieve flow distribution layer away from the conical hollow guide. An electromagnetic shielding protection mechanism is installed on the outside of the servo motor, surrounding the servo motor to isolate electromagnetic interference. A flexible vibration damping component is also installed on the side of the electromagnetic shielding protection mechanism away from the rotating stage to absorb the instantaneous impact force generated when the servo motor starts and brakes, so that the wafer maintains positional stability during the activation process.

3. The device for improving wafer plasma activation uniformity based on dynamic assistance according to claim 2, characterized in that, Natural frequency of a flexible damping assembly f n With driving frequency f d Satisfies the following relationship: , , k The stiffness of the flexible damping assembly, m The total mass of the rotating table and the wafer, The frequency safety threshold, f n ≤0.5 f d Or f n ≥2 f d , The stiffness of the flexible damping assembly can be adjusted.

4. The device for improving wafer plasma activation uniformity based on dynamic assistance according to claim 2, characterized in that, Angular velocity of the rotary stage ω Satisfies Radial constraint stiffness of the rotary stage to the wafer k r Not less than the minimum constraint stiffness at which the wafer does not slip relative to the rotary stage k min .

5. The device for improving wafer plasma activation uniformity based on dynamic assistance according to claim 1, characterized in that, The diameter of the conical hollow flow guide near the wafer end is larger than the diameter away from the wafer end, and the included angle of the conical surface of the central cross-section of the conical hollow flow guide... θ satisfy The average value of the inner diameter of the conical hollow guide D g Larger than the wafer diameter D w .

6. The device for improving wafer plasma activation uniformity based on dynamic assistance according to claim 1, characterized in that, The boundary flow disturbance device has multiple sets of flow disturbance truncated beams on its surface. The flow disturbance truncated beams are used to generate a micro-disturbance effect on the airflow passing through the boundary. The gap between the boundary flow disturbance device and the rotating platform is adjustable.

7. The device for improving wafer plasma activation uniformity based on dynamic assistance according to claim 1, characterized in that, The equivalent pore size per unit area of ​​the through holes in the sieve flow distribution layer d ( r ) and pore density per unit area n ( r The projection position of the via relative to the wafer center on the sieve flow distribution layer. r related, , , , R The effective radius of the uniformly distributed sieve layer. d (0) and n (0) represents the equivalent pore diameter per unit area and the pore density per unit area of ​​the projected position of the wafer center on the sieve flow distribution layer, respectively, and the open area ratio of the through-hole is... .

8. The device for improving wafer plasma activation uniformity based on dynamic assistance according to claim 7, characterized in that, The center distance between adjacent through holes on the sieve flow distribution layer P ( r The equivalent aperture per unit area at the location of the through hole. d ( r The following relationship is satisfied: .

9. The device for improving wafer plasma activation uniformity based on dynamic assistance according to claim 7, characterized in that, The height of the airflow stabilizing cavity H Average pore size per unit area of ​​the through-holes in the uniformly distributed sieve layer The following relationship must be satisfied: .

10. The device for improving wafer plasma activation uniformity based on dynamic assistance according to claim 2, characterized in that, It also includes a housing with an air inlet at the top and an air outlet at the bottom. Inside the housing is a device placement platform with several through channels. The device placement platform is used to place flexible vibration damping components and define the current position of the sieve flow distribution layer. An airflow stabilization cavity is formed between the device placement platform and the sieve flow distribution layer, and the channels connect the airflow stabilization cavity to the air outlet. The rotating platform, boundary flow disturbance device, and conical hollow guide are all housed inside the housing, and the output shaft of the servo motor passes through the electromagnetic shielding protection mechanism and the sieve flow distribution layer, and is connected to the rotating platform for transmission.

Images