Controllable non-uniform ceramic plate air outlet system and method

Abstract

The application discloses a controllable non-uniform ceramic plate gas outlet system and method for semiconductor plasma process. The system comprises: a double-layer ceramic base with a multi-region gas flow channel; a plurality of gas outlet hole arrays arranged on the base; a detection module for monitoring the etching depth of a wafer surface in real time; a control unit for closed-loop feedback control based on real-time detection data; a gas hole opening and closing execution mechanism driven and controlled by the control unit, which performs micro-motion actions according to control instructions to accurately control the opening and closing state and opening degree of the corresponding region gas outlet hole. The application dynamically and regionally regulates and controls the spatial distribution of the reaction gas in the chamber, effectively compensates for the uneven plasma distribution problem in the traditional scheme, realizes active control and improvement of wafer processing uniformity, and has the advantages of fast response speed, high control precision and strong adaptability.

Description

Technical Field

[0001] This invention relates to the field of semiconductor manufacturing equipment technology, specifically to a gas distribution system for process chambers such as plasma etching, chemical vapor deposition (CVD), or resist removal, and in particular to a controllable non-uniform ceramic plate gas outlet system and method capable of real-time and active regulation of the spatial distribution of reactive gases above the wafer. Background Technology

[0002] In advanced integrated circuit manufacturing, plasma processing is a key technology for achieving fine pattern etching and thin film deposition. Its basic principle is to generate plasma by exciting process gases within a vacuum chamber. The active ions and free radicals in the plasma then react physically or chemically with the wafer surface, thereby removing or growing materials. After the process is complete, the uniformity (often measured by the U-value) of the etching or deposition thickness at various points on the wafer surface is one of the core indicators for evaluating process quality.

[0003] However, existing solutions are all unable to meet the requirement of high uniformity. Summary of the Invention

[0004] The present invention aims to provide a controllable non-uniform ceramic plate gas outlet system and method, which achieves real-time control of the gas flow field by dynamically adjusting the opening and closing state of the gas outlet holes, thereby improving the processing uniformity.

[0005] This invention provides a controllable non-uniform ceramic plate gas outlet system for use in the process chamber of semiconductor manufacturing equipment, comprising:

[0006] The ceramic matrix is ​​internally configured to have multiple independent gas flow channel zones; in a preferred example, the ceramic plate can be made of alumina or aluminum nitride ceramic material, which has good high temperature resistance and insulation properties.

[0007] Multiple vent holes penetrate the lower surface of the ceramic substrate and are connected to the gas flow channel partition for conveying process gas into the process chamber. In practice, the vent holes can be designed in sections, and each section can be set with a uniform or non-uniform vent structure, or with vent structures of the same or different sizes.

[0008] The detection module is used to acquire etching depth data of multiple detection points on the wafer surface in real time. In practice, the detection device can be integrated above the optical window, and the detection principle can be to measure the etching depth in real time through the interferometer principle.

[0009] The control unit, which is signal-connected to the detection module and the vent opening / closing actuator, is configured to calculate the etching uniformity of the wafer surface based on the etching depth data and generate control commands. In practice, the control unit can preferably be a PLC or an embedded system, etc., to achieve closed-loop control based on the controller.

[0010] An vent opening / closing actuator is configured corresponding to the vent, connected to the control unit, and changes the effective flow area of ​​the vent according to the control command, thereby dynamically adjusting the gas flow rate of the vent in different areas to improve etching uniformity. In practice, the vent opening / closing actuator can preferably be a translational or rotatable structure (such as a baffle), and the method for determining the execution action can preferably be electromagnetic drive or piezoelectric drive, etc., to achieve microsecond-level response. In practice, the actuator can preferably be driven by a motor control method, such as a stepper motor or a servo motor.

[0011] Preferably, the ceramic substrate has a double-layer structure, including an upper ceramic plate and a lower ceramic plate joined to the upper ceramic plate. Grooves are formed between the upper ceramic plate and the lower ceramic plate by etching or grinding, and the grooves are configured as the independent gas flow channel partitions.

[0012] Preferably, the gas flow channel partitions are symmetrically distributed radially or in a fan shape around the center of the ceramic substrate, and each partition is connected to an independent air intake source or connected to the main air intake source through an adjustable valve group located upstream of the substrate.

[0013] Preferably, the vent opening and closing actuator includes a vent baffle that can move relative to the vent. The vent baffle is fan-shaped, rectangular, circular, or an irregular structure (such as an arbitrary polygon) that matches the shape of the flow channel partition. Different shapes and sizes can be selected according to different process requirements during implementation.

[0014] And / or, the vent opening and closing actuator includes a miniature linear motor, a piezoelectric ceramic driver, or a voice coil motor; in practice, a servo motor with high-precision position control capability can be selected.

[0015] And / or, the pore opening / closing actuator includes a connecting rod for transmitting actions within the ceramic substrate, wherein the connecting rod is a rigid link, a flexible hinge, or a bellows structure. In a preferred embodiment, the connecting rod may be made of titanium alloy, which has high strength and a low coefficient of thermal expansion.

[0016] Preferably, the pore baffle is made of a material whose coefficient of thermal expansion matches that of the ceramic substrate. The material is Kovar alloy, titanium alloy, or a metal material with a ceramic coating on its surface. A flexible sealing layer is provided between the pore baffle and the lower surface of the ceramic substrate. The flexible sealing layer is a polyimide film or a metal corrugated gasket.

[0017] And / or, the driving mechanism is a miniature linear motor, a piezoelectric ceramic driver, or a voice coil motor, and the driving mechanism is connected to the air hole baffle via a connecting rod, which is a rigid connecting rod, a flexible hinge, or a bellows structure.

[0018] Preferably, the detection module is an interferometric endpoint detection device (i.e., an IEP module), which includes a broadband light source, a beam splitter, a reference mirror, and a spectrometer. The interferometric endpoint detection device measures the wafer surface through an optical window located at the top of the process chamber and calculates the etching depth by analyzing the interference spectrum of the reflected light and the reference light. In practice, the IEP detection device integrates optical sensors, phase difference calculation algorithms, and other units, thereby outputting detection data in a timely manner based on the interferometric detection principle.

[0019] And / or, the vent holes are non-uniformly distributed on the lower surface of the ceramic substrate, with a higher vent hole density and / or a larger vent hole diameter in areas where the expected etching rate is slower;

[0020] And / or, the controllable non-uniform ceramic plate gas outlet system further includes a pressure sensor array, which is disposed in each of the gas flow channel partitions to monitor the real-time pressure of each partition. The control unit is also configured to adjust the vent opening and closing actuator and / or the intake valve according to the monitored pressure data to achieve coordinated control of flow rate and pressure.

[0021] Preferably, the control unit is configured to perform one or more of the following control processes:

[0022] S1: Receive real-time erosion depth data D(x,y,t) from the detection module, where (x,y) are the coordinates of the detection point and t is the time.

[0023] S2: Calculate the etching uniformity index U value of the wafer surface at the current moment, where the index U value is the standard deviation or range value of the depth values ​​of all detection points;

[0024] S3: Compare the index U value with a preset threshold U0. If U>U0, it is determined that the uniformity does not meet the standard, and step S4 is executed.

[0025] S4: Analyze the spatial distribution of depth data D to identify areas with excessively slow and excessively fast etching rates;

[0026] S5: Based on the recognition results, generate control instructions: increase the opening of the vent above the area with slow etching, and / or decrease the opening of the vent above the area with fast etching.

[0027] S6: Send a control command to the vent opening / closing actuator to perform a fine-tuning action that changes the effective flow area of ​​the vent.

[0028] Preferably, the control unit has a pre-stored process model, which has a preset mapping relationship between the etching depth distribution and the opening and closing state of the vent. The generation of the control command is based on the process model and combines feedforward control and closed-loop feedback control.

[0029] Preferably, the process model is a neural network model trained based on a machine learning algorithm. Its inputs include historical etching depth data, current process parameters, and vent status, and its output is an optimized vent control command.

[0030] The present invention also provides a gas flow control method based on any one of the systems described herein, comprising the steps of:

[0031] The etching depth distribution on the wafer surface is monitored in real time using a detection module.

[0032] Based on the etching depth distribution, determine whether the etching uniformity deviates from expectations;

[0033] If the deviation from the expected behavior is detected, the vent opening and closing actuator is controlled to adjust the vent opening and closing status, thereby changing the gas flow rate of the vent in the corresponding area, thus correcting the spatial distribution of the reacting gas in the chamber and improving the uniformity of plasma density.

[0034] Compared with the prior art, the beneficial effects of the present invention include:

[0035] This invention solves the long-standing uniformity problem in plasma processes during semiconductor manufacturing by employing an innovative closed-loop control system based on "sensing-decision-execution." The resulting technical benefits can be seen in one or more of the following aspects:

[0036] On the one hand, a closed-loop control architecture of "perception-decision-execution" is creatively adopted to achieve real-time dynamic control of the wafer processing process;

[0037] Secondly, the detection (such as the IEP module) and the air hole actuator are integrated into a closed-loop control, which makes the response speed faster than the traditional air circuit control method, for example, the response speed is 10-100 times that of the traditional air circuit.

[0038] In three aspects, modular design and pore zone control design facilitate flexible adjustment of process gas control strategies according to different process requirements, thereby improving the flexibility of uniformity control.

[0039] In four aspects, CTE matching materials and flexible sealing design are adopted to solve the reliability problem of actuators in high temperature vacuum environments;

[0040] In five aspects, the system can collect and generate a large amount of process data, so that these process data can be used to build intelligent process models based on machine learning algorithms in the later process optimization, which will facilitate the transformation of the process route from passive response optimization to active prediction after the model is embedded into the control system. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the closed-loop control for forming a controllable non-uniform airflow field on the ceramic plate of the present invention;

[0042] Figure 2 This is a vertical cross-sectional schematic diagram of the controllable non-uniform ceramic plate gas outlet system in this invention;

[0043] Figure 3 This is a schematic cross-sectional view of the controllable non-uniform ceramic plate gas outlet system in this invention.

[0044] Figure 4 This is a schematic diagram of the control unit operation of the controllable non-uniform ceramic plate gas outlet system in this invention.

[0045] Figure 5 This is a schematic diagram of the gas flow control method for a controllable non-uniform ceramic plate gas outlet system according to the present invention. Detailed Implementation

[0046] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0047] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0048] It should be noted that various aspects of embodiments within the scope of the appended claims are described below. It will be apparent that the aspects described herein can be embodied in a wide variety of forms, and any particular structure and / or function described herein is merely illustrative. Based on this invention, those skilled in the art will understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number and aspects set forth herein can be used to implement the device and / or practice the method. Additionally, this device and / or method can be implemented using structures and / or functionalities other than one or more of the aspects set forth herein.

[0049] It should also be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. The drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0050] Additionally, specific details are provided in the following description to facilitate a thorough understanding of the examples. However, those skilled in the art will understand that practice can be carried out without these specific details.

[0051] Achieving high uniformity (U-value) in semiconductor plasma processing has been a long-term goal of the industry and an extremely complex technical challenge.

[0052] In existing technologies, fixed gas distribution plates, also known as showerheads, are typically used. The size and distribution of the air outlets on these plates are fixed after pre-simulation and design, aiming to provide an initial, static, and uniform airflow.

[0053] Through long-term research and numerous experiments, this invention has gained a profound understanding that the root cause of the uniformity problem lies in the spatial asymmetry of the distribution of reactive gas and plasma within the process chamber. This asymmetry is both inherent and dynamic.

[0054] On the one hand, the inherent nature of these issues stems from the inherent limitations of the equipment's physical structure. For example, static designs cannot cope with dynamic and random disturbances, nor can they adapt to different gas flow rates and pressure requirements under different process formulations. In particular, when process conditions change or the state of components drifts after long-term operation, the original optimal design may fail, leading to poor uniformity. For instance, it is difficult to achieve absolute symmetry in the physical structure of a process chamber. To maintain a vacuum, the chamber is usually connected to a pump port. The presence of the pump port disrupts the symmetry of the chamber, resulting in inherent differences in the gas flow field and plasma distribution at different distances from the pump port, forming the so-called "pumping effect." Furthermore, the Lorentz force exerted by the Earth's magnetic field on the trajectory of charged particles (electrons, ions), although weak, causes a systemic east-west or north-south deviation that cannot be ignored at the nanoscale of fabrication. In addition, the feed point of the radio frequency power and the non-uniform losses on the inner wall surface of the chamber introduce inherent asymmetry sources that cannot be completely eliminated through mechanical design.

[0055] Secondly, the dynamic nature of the process stems from the fact that the process is not static. Different products have different process formulations (such as gas type, flow rate, pressure, and RF power), which can lead to changes in plasma impedance and distribution. In addition, after years of operation, the cleanliness of the chamber walls and the aging of components can drift, a phenomenon known as "process drift." This means that even when the static gas distribution plate is adjusted to its optimal state during equipment acceptance, the process uniformity may begin to deteriorate after several months or even weeks.

[0056] Therefore, the core flaw of existing technologies lies in their "static" and "passive" nature. Neither uniformly distributed gas distribution plates nor gas systems that can only be manually pre-adjusted in zones can cope with the aforementioned inherent, dynamic non-uniformity challenges.

[0057] Therefore, the industry urgently needs a technical solution that can dynamically and in real time adjust the gas distribution to actively compensate for the non-uniformity caused by various factors and stably control the U value of the process within the optimal range.

[0058] In other words, the motivation for this invention stems from a strong technological need: whether it is possible to create an "intelligent" gas distribution system that can not only "see" (i.e., sense) the real-time non-uniformity of the wafer surface processing state, but also "think" (i.e., decide) its causes, and immediately "take action" (i.e. execute) dynamically adjusting the spatial distribution of the gas, thereby proactively and in real-time compensating for non-uniformity caused by various factors. Therefore, if "sensing," "decision-making," and "actuation" can be integrated into a closed-loop control concept, it will help solve the aforementioned problems.

[0059] Based on the above analysis, this invention proposes a disruptive technical concept: (Refer to...) Figure 1 This invention illustrates a shift from the traditional concept of "static gas distribution" to the concept of "dynamic airflow field control." The core ideas of this invention are interconnected and mutually supportive:

[0060] On the one hand, real-time perception across the entire domain ("eyes"): By using monitoring methods, it can "see" the etching or deposition depth happening at every point on the wafer surface in real time, just like an "eye", rather than only knowing the results through random inspection after the process is completed.

[0061] In implementation, optical detection technology can be used as a sensing method, such as interferometric endpoint detection (IEP). By continuously measuring the optical path difference between the reflected light and the reference light on the wafer surface during the process, it can calculate the real-time changes and spatial distribution of the etching depth with nanometer-level precision. This provides unprecedented, high-precision, and full-field data input for closed-loop control.

[0062] Secondly, intelligent decision-making and control ("brain"): adopting corresponding decision-making mechanisms, just like having a "brain" that can quickly process the information seen by the "eyes", judge the unevenness pattern and degree, and calculate the best correction strategy.

[0063] In implementation, a high-speed control unit can be designed. Its built-in control algorithm first converts the IEP data into real-time uniformity indicators, such as within-wafer non-uniformity (WIWNU), and compares it with a set threshold. Once the deviation exceeds the limit, the process model is invoked. This model can be a simple mapping based on physical principles (e.g., "If region A is too thin, increase the airflow to region A"), or it can be a more advanced neural network model trained based on machine learning. The latter can learn complex nonlinear relationships in historical process data, achieving intelligent mapping from "current depth distribution" to "optimal porosity adjustment instructions," and even performing feedforward predictions to act in advance.

[0064] In three aspects, it can execute quickly and accurately ("hands"): Based on the decisions and instructions given by the aforementioned "brain", it can execute the corresponding dynamic control in a timely and accurate manner, just like having a pair of "nimble hands" that can faithfully execute the instructions issued by the "brain" and dynamically make precise adjustments to the gas distribution at the micron and millisecond levels.

[0065] In practice, the execution function can be implemented through creative physical means. For example, instead of the slow traditional method of adjusting upstream gas valves, a miniature actuator (such as a motor / piezoelectric actuator) is creatively integrated directly onto the ceramic gas distribution plate. By designing a gas outlet baffle mechanism, the actuator drives it to make minute displacements, directly controlling the effective opening of each or each group of gas outlets. This "terminal control" method eliminates the lengthy gas delivery pipeline delay, improving the response speed from "tens of seconds" in traditional methods to "milliseconds to seconds," matching the dynamic changes in the plasma process.

[0066] It should be noted that the above three core concepts are interdependent and indispensable: for example, without real-time perception by IEP, decision-making and execution control become aimless; for example, without intelligent decision-making, it is impossible to process complex data and provide optimal solutions; and for example, without a rapid execution mechanism, even the best decisions cannot be implemented and a closed loop cannot be formed.

[0067] The aforementioned closed-loop collaborative process of "perception-decision-execution" is the fundamental difference between this invention and all existing technologies.

[0068] It should be noted that in transforming the above-mentioned technical concept into an implementable technical solution, the present invention also innovatively proposes a series of meticulous designs.

[0069] For example, the integration of high-temperature resistant, high-precision actuators within vacuum chambers. Plasma process chambers are high-vacuum, high-temperature environments with strong electromagnetic fields. Conventional motors struggle to operate stably in this environment, and the potential particulate contaminants and magnetic field interference they generate are unacceptable. This invention proposes a feasible solution: preferably using a non-magnetic, high-temperature resistant miniature voice coil motor or piezoelectric ceramic actuator, and employing a vacuum feedthrough mounting method. The drive mechanism can be installed outside the reaction environment chamber, and motion is transmitted to the actuator inside the chamber (e.g., a gas vent baffle) via a rigid linkage or flexible bellows transmission mechanism. This isolates the potentially problematic drive component from the harsh reaction environment within the chamber, perfectly solving the compatibility problem.

[0070] For example, regarding ensuring long-term reliable airtightness, extremely high airtightness must be maintained between the movable vent baffle and the fixed ceramic plate to prevent gas leakage into the wrong area, while also being resistant to plasma corrosion, high temperatures, and having a low coefficient of friction. This invention proposes a feasible solution: a flexible sealing scheme. An ultra-thin flexible sealing membrane, such as polyimide (PI) or Teflon (PTFE), is added between the metal baffle and the ceramic plate. Utilizing the membrane's excellent elasticity, heat resistance, and chemical inertness, it effectively achieves a seal while minimizing the resistance to the baffle's minute movements (i.e., almost no resistance or minimal resistance). Preferably, a metal bellows can be used as a dynamic seal to achieve a completely frictionless seal.

[0071] For example, regarding thermal matching and thermal management, the temperature of the ceramic plate rises during the process, and a mismatch in the coefficient of thermal expansion (CTE) between it and the metal baffle and connecting rod can generate thermal stress, leading to jamming or inaccurate positioning. This invention proposes a feasible solution: critical structural components are designed with CTE matching. For example, Kovar or Invar alloys can be used to make the pore baffle and connecting rod, as their CTE is very close to that of alumina ceramic, which can greatly suppress thermal stress.

[0072] For example, in terms of the practical application of control algorithms. Generally speaking, plasma process control systems are a class of highly complex nonlinear systems, making it extremely difficult to establish accurate physical models of the control process. This invention proposes a feasible solution: employing a data-driven machine learning method. By collecting a large amount of IEP data, porosity, and final uniformity results under different process conditions, a convolutional neural network (CNN) or recurrent neural network (RNN) model is trained. This model can automatically learn the complex relationships involved, achieving high-quality control without the need for precise physical equations. The model is embedded into a real-time industrial controller (such as an industrial PC, PLC, etc.) to achieve intelligent closed-loop control.

[0073] In summary, the successful implementation of this technical concept has brought about unexpected technical effects:

[0074] First, the leap from "static preset" to "dynamic adaptive": existing technologies can only perform static, preset flow adjustments for different zones, and cannot cope with the dynamic disturbances that occur randomly during the process.

[0075] Second, a paradigm shift from "open-loop" to "closed-loop": the semiconductor manufacturing process has been transformed from an open-loop model of "preset formula and expected result" into an intelligent closed-loop process of "real-time perception, dynamic adjustment and ensuring result" in this application scenario for the first time, bringing an order-of-magnitude improvement in uniformity and achieving a qualitative leap.

[0076] Third, it solves the core engineering challenge of "time delay": traditional solutions, even with detection, cannot achieve effective closed-loop control due to slow actuator response (such as regulating gas valves) and long control cycles. This invention, by directly integrating the actuator structure onto the gas distribution plate, achieves a response speed in the millisecond to second range, matching the time constant of the process. This improves the response speed by one to two orders of magnitude, making real-time closed-loop control truly possible—a completely new function that has not been proposed or implemented in existing technologies.

[0077] Fourth, it possesses strong anti-interference and adaptive capabilities: whether it is chamber pressure fluctuation, RF power jump, or equipment state drift, the system can automatically compensate through closed-loop feedback, significantly improving the robustness and repeatability of the process.

[0078] Fifth, it opens up new avenues for process optimization: the system can collect and generate a large amount of process data, not only to provide a data foundation for future process optimization, but also to use it for in-depth analysis and machine learning iteration, so that the process model can be continuously optimized, and may even discover better process windows that cannot be discovered by humans, making the equipment smarter the more it is used.

[0079] Therefore, the technical concept of this invention is not a simple improvement or combination of existing technologies, but rather a completely new and systematic solution to a fundamental problem that has long existed in the industry. It creatively integrates real-time detection, intelligent decision-making, and terminal execution into an organic and dynamic intelligent control system, ultimately achieving a fundamental improvement in process uniformity.

[0080] The following examples illustrate each implementation instance.

[0081] Example 1: Basic Controllable Non-uniform Ceramic Plate Gas Exhaust System

[0082] See Figure 2 and Figure 3 The present invention provides a controllable non-uniform ceramic plate gas outlet system, which is set inside the process cavity. The system may include: a ceramic substrate 10, a pore opening and closing actuator 20, a detection module (not shown in the figure) and a control unit (not shown in the figure).

[0083] In some examples, the ceramic substrate 10 is located in the space above wafer 1 and wafer stage 2. The ceramic substrate 10 is made from high-purity Al2O3 or AlN ceramic materials through a sintering process, exhibiting good insulation, corrosion resistance, and mechanical strength. Specifically, the ceramic substrate 10 can be made from high-purity (e.g., 99.6%) alumina (Al2O3) ceramic material, manufactured through isostatic pressing and high-temperature sintering (e.g., at 1650℃ for 4 hours), thus utilizing Al2O3's excellent insulation properties, high mechanical strength (e.g., flexural strength > 300 MPa), and good plasma corrosion resistance. When using aluminum nitride (AlN) ceramic, its higher thermal conductivity makes it better suited for high-power applications.

[0084] In some examples, the ceramic substrate 10 is preferably configured as a double-layer structure, including an upper ceramic plate and a lower ceramic plate joined to the upper ceramic plate. Grooves are formed between the upper and lower ceramic plates, and these grooves are configured as independent gas flow channel partitions. For example, a series of radially distributed grooves are machined on the upper surface of the lower ceramic plate and / or the lower surface of the upper ceramic plate by etching (photolithography and reactive ion etching, etc.) or grinding processes. After the upper and lower ceramic plates are joined, these grooves form multiple isolated fan-shaped gas flow channel partitions. One end of each flow channel partition is connected to an independent gas inlet, and the other end is connected to a series of precision-machined vent holes 110. For example, in a precision-designed double-layer structure of the ceramic substrate, the upper ceramic plate has a thickness of 3.0 mm, a flatness tolerance of <0.05 mm, and a surface roughness Ra <0.4 μm; the lower ceramic plate has a thickness of 2.5 mm and is machined with precision flow channels by photolithography and reactive ion etching (RIE) processes.

[0085] In some examples, radially distributed grooves are created only on the surface of the lower ceramic plate using photolithography. For example, groove depth: 0.8mm ± 0.05mm; groove width: 1.2mm ± 0.1mm; number of partitions: 12 fan-shaped regions (each with a 30° central angle); partition isolation: each fan-shaped region is completely isolated to prevent gas crosstalk.

[0086] In some examples, the gas flow channels are symmetrically distributed radially or in a fan shape around the center of the ceramic substrate. Each channel is connected to an independent air intake source or connected to the main air intake source through an adjustable valve group located upstream of the substrate, thereby enabling flexible control of different gas flow channels and zones.

[0087] In some examples, the diameter of the vents 110 ranges from 0.1 mm to 0.5 mm, distributed across different fan-shaped regions, with varying or uniform distribution densities. For instance, in regions near the pump inlet where a faster expected pumping rate is anticipated, the density is set higher to pre-compensate for airflow asymmetry. For example, the vents 110 are spaced smaller in the central region and larger around the periphery. For example, the vent spacing is 1.5 mm near the pump inlet, forming a high-density vent region, while it is 3.0 mm further away, forming a low-density vent region. For example, the vents are non-uniformly distributed on the lower surface of the ceramic substrate, facilitating higher vent density and / or larger vent diameters in regions with slower expected etching rates.

[0088] In some examples, the shape (i.e., orifice type) of the vent 110 can be set as a tapered orifice, with a diameter on the inlet side slightly larger than that on the outlet side, which can reduce airflow resistance.

[0089] In some examples, the shape of the vent baffle 230 is fan-shaped, rectangular, circular, or an irregular structure that matches the shape of the flow channel partition.

[0090] In some examples, the pore baffles are made of a material whose coefficient of thermal expansion matches that of the ceramic matrix, such as Kovar alloy, titanium alloy, or a metal material with a ceramic coating.

[0091] For example, the pore baffle 230 is made of 4J29 Kovar alloy, whose coefficient of thermal expansion is close to that of Al2O3 ceramic, reducing the impact of thermal stress. In addition, the thickness of the baffle is preferably 0.8 mm, and the surface is chemically plated with nickel (e.g., 8 μm thick) to improve corrosion resistance and surface hardness.

[0092] In some examples, a flexible sealing layer is provided between the pore baffle 230 and the lower surface of the ceramic substrate. This flexible sealing layer is preferably a polyimide film or a corrugated metal gasket. For example, the sealing layer is a 25μm thick polyimide film, adhered to the baffle surface using a high-temperature resistant adhesive.

[0093] In some examples, the vent opening and closing actuator may include a drive motor 210, which may preferably be a micro linear motor, a piezoelectric ceramic driver, or a voice coil motor. For example, using a voice coil motor for direct drive can avoid the backlash problem of traditional lead screw or gear transmission, and can also achieve millisecond-level dynamic response, keeping up with the rapid fluctuations that may occur in plasma processes (such as instantaneous non-uniformity caused by RF power jumps).

[0094] In some examples, the pore opening and closing actuator may include a connecting rod 220 to transmit motion within the ceramic substrate. In these examples, the connecting rod 220 may be a rigid link, a flexible hinge, or a bellows structure. For instance, the connecting rod 220 is preferably a rigid rod made of 316L stainless steel (e.g., a rigid rod with a diameter of 6 mm), which is connected to the baffle via a self-aligning ball joint (e.g., a ball head radius of 3 mm), compensating for installation alignment errors (up to ±0.5 mm) and displacement caused by thermal deformation, thus achieving higher precision control of the baffle's minute displacements.

[0095] In some examples, the control unit is configured as the core unit for acquiring and processing data. (See reference.) Figure 4 As shown, the control unit can execute one or more of the following example control processes.

[0096] For example, the control unit receives real-time erosion depth data D(x,y,t) from the Interferometric Endpoint Detection (IEP) module, where (x,y) are the coordinates of the detection point and t is time. The IEP provides high-precision, full-field depth data, offering unprecedented data support for zonal fine-tuning, which in turn maximizes the value of the IEP data.

[0097] For example, the control unit calculates the etching uniformity index U value of the wafer surface at the current moment, where the index U value is the standard deviation or range value of the depth values ​​of all detection points.

[0098] For example, the control unit compares the index U value with a preset threshold U0. If U > U0, it determines that the uniformity does not meet the standard.

[0099] For example, the control unit analyzes the spatial distribution of depth data D to identify areas with excessively slow or excessively fast etching rates.

[0100] For example, based on the identified spatial distribution, the control unit generates control commands: increase the opening of the vent above the area with slow etching, and / or decrease the opening of the vent above the area with fast etching.

[0101] For example, the control unit sends control commands to the drive mechanism to drive the vent opening and closing actuator to operate.

[0102] In some examples, the detection module is preferably an IEP module (i.e., an interferometric endpoint detection device), which includes a broadband light source, a beam splitter, a reference mirror, and a spectrometer. The interferometric endpoint detection device is located through an optical window positioned at the top of the process chamber (see above). Figure 2(Illustrative image) Measurements are performed on the wafer surface, and the etching depth is calculated by analyzing the interference spectrum of the reflected light and the reference light. It should be noted that the IEP module can be a mature, commercially available product, or a product modified for different applications; no specific limitations are made here.

[0103] In some examples, gas flow control can also utilize a pressure sensor array to sense real-time pressure for fine-tuning. In practice, the pressure sensor array is positioned within each gas flow channel partition to monitor the real-time pressure of each partition. The control unit is also configured to adjust the orifice opening / closing actuator and / or the intake valve (e.g., a valve installed on the pipeline) based on the monitored pressure data, achieving coordinated control of flow and pressure. For example, when the gas pressure deviates significantly from the target value, the intake valve can be adjusted to quickly reach the desired pressure range; conversely, when the gas pressure deviates slightly from the target value, the orifice opening / closing actuator can be adjusted to perform micro-displacement movements for high-precision adjustment.

[0104] Example 2: Concentric Circular Partitioning and Rotation Drive Scheme

[0105] This embodiment provides an alternative implementation method, which adopts a concentric annular gas flow channel partition design, suitable for application scenarios where wafer edge effects are significant.

[0106] In some examples, the ceramic substrate 10 adopts a multi-layer composite structure: the base layer is a 2.0 mm thick AlN ceramic, which provides good thermal conductivity; the flow channel layer is a 1.5 mm thick Al2O3 ceramic, which is processed with concentric annular flow channels; and the gas outlet surface is a 1.0 mm thick Al2O3 ceramic, which is laser-processed with a micropore array.

[0107] In some examples, the design parameters for the concentric annular flow channel are as follows: the number of rings is 5 independently controlled annular regions; the ring width is 15mm, 20mm, 25mm, 30mm, and 40mm from the center to the edge; and the isolation method is that each annular region is isolated by a 0.5mm wide sealing wall.

[0108] In some examples, the rotary vent opening and closing mechanism features a vent baffle 230 designed as a disc-shaped structure with the same diameter as the ceramic substrate and a thickness of 1.2 mm. The material used is Invar 36, whose ultra-low coefficient of thermal expansion ensures dimensional stability at high temperatures. The baffle is machined with an array of arc-shaped holes corresponding to the vent 110, and the opening is controlled by precise rotation. The holes are fan-shaped with an angle of 10°, and the radial length is adjusted according to the annular area. The opening is controlled by a rotation angle of 0-30°, corresponding to an opening of 0-100%. The resolution is 0.1° for the rotation angle, corresponding to an opening change of approximately 0.3%.

[0109] In some examples, the drive motor 210 uses a combination of a servo motor and a precision reducer (reduction ratio 50:1), with a rated torque of 2.5 N·m, a maximum speed of 6000 rpm, a positioning accuracy of ±5 arcseconds, a repeatability of ±1 arcsecond, and an angle sensor using an absolute encoder (23-bit resolution) directly mounted on the motor shaft to provide real-time position feedback.

[0110] In some examples, the detection module uses a white light interferometer instead of a standard IEP system to provide full-field three-dimensional topography measurement, which can simultaneously acquire etching depth and surface roughness information.

[0111] In summary, examples employing concentric annular partitioning typically possess one or more of the following characteristics: better matching the rotational symmetry of wafer processes; while control precision in the central region is relatively lower, it more effectively addresses non-uniformity issues in the edge regions; fewer annular partitions (usually 5-7 rings), resulting in a relatively simplified control system; and a compact, space-saving rotational drive structure. Therefore, applicable scenarios include: post-wafer-level chemical mechanical polishing (CMP) cleaning; plasma-enhanced chemical vapor deposition (PECVD) with strong rotational symmetry; and advanced packaging processes requiring extremely high edge uniformity.

[0112] Example 3: A controllable non-uniform ceramic plate gas outlet system with a certain degree of intelligence and prediction

[0113] In some examples, a process model is pre-stored within the control unit. This model can pre-define a mapping relationship between etching depth distribution and the opening / closing state of vents, such as a mapping relationship between etching depth distribution and vent opening / closing data in different regions, derived from production experience. Control commands are then generated in real-time based on this mapping relationship, enabling the generation of control commands to combine feedforward control and closed-loop feedback control based on this process model. Here, closed-loop control refers to the closed-loop control process between the detection unit, control unit, and actuator in the aforementioned examples.

[0114] Real-time control strategies can be implemented based on the process model, where the system employs a composite control strategy of predictive feedforward and feedback correction. For example, feedforward control (the main action) adjusts the opening of the gas outlet 10-30 seconds in advance and responds promptly to common disturbances such as RF power changes, process recipe switching, and chamber temperature drift. Feedback correction control (the auxiliary action) performs small-amplitude corrections based on real-time IEP measurement data and flexibly responds to unpredictable disturbances such as gas purity fluctuations and random equipment noise.

[0115] In some examples, the system can acquire a large amount of real-time process data, thus enabling the use of artificial intelligence to train a new process model, achieving a certain level of intelligence and predictive capability. In implementation, a neural network model trained using machine learning algorithms serves as the process model. The inputs to the neural network model include historical etching depth data, current process parameters, and vent status, while the output is optimized vent control commands.

[0116] In intelligent process models, adaptive learning mechanisms can also be adopted. For example, the system can automatically perform model updates every week, such as collecting new process data (about 500 data points), incremental training, retaining old model versions, and rolling back when necessary.

[0117] By introducing machine learning models, the system can not only perform passive feedback compensation but also proactive feedforward prediction. For example, the model learns that when the RF power changes in a specific mode, it usually causes non-uniformity at a specific location on the wafer edge. Therefore, the porosity of the corresponding area can be adjusted in advance before the non-uniformity is actually detected by the IEP, achieving more advanced and precise control and significantly improving control quality and process stability.

[0118] Example 4: Using piezoelectric drive and micropore array structure

[0119] Based on the above embodiments, the present invention can also achieve precise control of the opening and closing degree of the air outlet in another way.

[0120] In this embodiment, the vent opening / closing actuator 20 is not a translational baffle, but rather an array of piezoelectric actuators. Above each vent 110 of the ceramic substrate 10, a miniature piezoelectric ceramic unit (not shown in the figure) is correspondingly disposed. When not energized, each piezoelectric ceramic unit, because its length is slightly greater than the channel height, has its lower sealing plug (which can be made of polyetheretherketone (PEEK) or rubber material) pressed against the upper port of the vent under preload, thus closing it. When a voltage is applied to the piezoelectric ceramic unit, it generates an inverse piezoelectric effect, undergoing axial contraction, which drives the sealing plug upward, thereby opening the vent. The degree of opening / closing can be precisely controlled by the applied voltage value.

[0121] By achieving the highest level of control precision through independent, digital control of each vent, it eliminates complex mechanical transmission mechanisms and boasts extremely fast response times (down to the microsecond level). It is particularly suitable for advanced processes requiring extremely high uniformity control.

[0122] Example 5: Thermal Expansion Driven and Application of Shape Memory Alloys

[0123] This embodiment provides another example of realizing the opening and closing of vents, which utilizes the principle of heat drive.

[0124] The vent baffle 230 is made of a bimetallic strip or a shape memory alloy (SMA, such as nitinol). One end of the baffle is fixed, and the other end is free, corresponding to a set of vent holes. The driving mechanism is a miniature heating resistor integrated near the baffle, and the control unit precisely controls the temperature of the baffle by controlling the current flowing into the heating resistor. When the temperature changes, the bimetallic strip will bend due to the difference in thermal expansion coefficients of the materials on both sides; or the shape memory alloy will undergo a phase transition, restoring its memory shape, thereby generating displacement and controlling the opening and closing degree of the vent holes below it.

[0125] This example features a simple structure, requires no moving parts such as motors, and boasts high reliability, making it ideal for ultra-clean environments with extremely high cleanliness requirements. Shape memory alloys offer advantages such as high driving force and high displacement accuracy.

[0126] Example 7: Control Strategy Optimization for Control Units

[0127] This example provides further optimization for the control unit. For instance, in the initial stage, rule-based control (such as PID control) can be used to quickly suppress major non-uniformities. Once the process reaches a stable stage, a switch to high-precision control or adaptive control mode can be made to further optimize control performance and reduce overshoot.

[0128] Even better, the system can possess self-learning capabilities. After each process, the system stores all process data (sensor data, control commands, and final uniformity results) into the database. This data is periodically used to incrementally train and fine-tune the internal process model (such as the neural network model in the previous example), enabling the model to continuously adapt to changes in equipment status (such as changes in chamber cleanliness), thus achieving a "get smarter with use" effect. By possessing continuous learning capabilities, it offers better flexibility and accuracy compared to any fixed-parameter control scheme.

[0129] Example 6: Method for forming controllable non-uniform gas flow rate using a ceramic plate

[0130] This example is based on the controllable non-uniform ceramic plate gas outlet system provided in any of the foregoing embodiments. Through closed-loop control, the opening and closing degree of the gas outlet holes in the ceramic plate is precisely controlled, thereby forming a controllable non-uniform gas flow that can be actively regulated in real time to improve the spatial distribution of the reaction gas above the wafer.

[0131] refer to Figure 5 As illustrated, a gas flow control method provided by the present invention may include:

[0132] S202. Real-time monitoring of the etching depth distribution on the wafer surface via a detection module. In implementation, the etching depth data of the wafer surface can be acquired in real time through the IEP module. For example, data acquisition parameters include: a sampling frequency of 10Hz (acquiring full-field data every 0.1 seconds), 49 measurement points (7×7 array, covering the entire 300mm wafer surface), a measurement accuracy of ±0.5nm (3σ value), and a two-dimensional matrix D(x,y,t) data format, where x and y are coordinate indices and t is a timestamp. During acquisition, multiple averaging (usually 5 times) can be used to reduce random noise. Real-time calibration of the reference standard wafer can also be performed every 30 minutes to eliminate system drift. Furthermore, data integrity checks, such as detecting missing data and triggering alarms when the missing data exceeds 10%, can improve data accuracy.

[0133] S204. Based on the etching depth distribution, determine whether the etching uniformity deviates from the expected value. In practice, the uniformity index can use within-wafer non-uniformity (WIWNU) as the main criterion, and range / mean ratio, 3σ value, etc. as auxiliary criterions.

[0134] S206. If the deviation from the expected value is detected, the vent opening / closing actuator is activated to adjust the vent opening / closing status, thereby changing the gas flux through the vents in the corresponding area. This corrects the spatial distribution of the reactant gas within the chamber and improves plasma density uniformity. In practice, the threshold setting can be a target value U0 (typically 1.5-2.0%) set according to process requirements. In some examples, simple linear regression analysis can be used to analyze the WIWNU change trend over the past 30 seconds. If it is predicted that WIWNU will exceed the threshold in the next 60 seconds, the control action can be triggered in advance.

[0135] In some examples, the control process can be one or more of the following: For example, the control resolution can be 0.1% opening (corresponding to an air vent baffle displacement accuracy of ±1μm); for example, the response time: from command issuance to execution completion <100ms; for example, sequential control: using a ramp adjustment method to avoid sudden airflow changes; for example, the adjustment rate: 5% / s (i.e., approximately 20 seconds from fully closed to fully open); for example, zone sequence: executing according to the severity of the problem, etc.

[0136] In some examples, the control process can incorporate additional safety protection mechanisms. For instance, limit position protection: physical limit + software limit (opening degree 0-100%); sudden change protection: single adjustment amount limit (<20%); interlock protection: interlocked with the plasma power supply, maintaining the current state in case of an anomaly, etc.

[0137] In some examples, the control process can employ multi-parameter coordinated control. For instance, gas flow and pressure coordination: adjusting the orifice opening while coordinating with the upstream pressure control valve; temperature compensation control: adjusting the gas temperature or flow rate based on the wafer temperature distribution; RF power matching: collaboratively adjusting the RF matching network parameters based on changes in plasma impedance, etc.

[0138] The above method achieves precise control of wafer surface etching uniformity through closed-loop control of real-time monitoring, intelligent decision-making, and precise execution. It also achieves simultaneous improvement in uniformity and response speed. For example, in terms of uniformity improvement, WIWNU stabilizes the uniformity from 5-8% in traditional methods to 1.2-1.8%. In terms of response speed improvement, the response time to process disturbances is only tens of seconds (e.g., less than 15 seconds), and it is applicable to various process formulations without much debugging.

[0139] Therefore, closed-loop control enables precise control of the wafer etching process, significantly improving the stability of semiconductor manufacturing processes and product yield.

[0140] In this specification, the same or similar parts between the various embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the descriptions of the embodiments described later are relatively simple, and relevant parts can be referred to the descriptions of the foregoing embodiments.

[0141] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A controllable non-uniform ceramic plate gas outlet system for a process chamber of a semiconductor manufacturing apparatus, characterized in that, include: The ceramic matrix is ​​internally structured with multiple independent gas flow channel zones. Multiple vent holes penetrate the lower surface of the ceramic substrate and are connected to the gas flow channel partition for conveying process gas into the process chamber. The detection module is used to acquire etching depth data of multiple detection points on the wafer surface in real time; The control unit, which is signal-connected to the detection module and the pore opening / closing actuator, is configured to calculate the etching uniformity of the wafer surface based on the etching depth data and generate control commands. A vent opening / closing actuator, corresponding to the vent, is connected to the control unit and performs micro-displacement actions according to the control command to precisely control the opening / closing state and opening degree of the vent in the corresponding area, thereby changing the effective flow area of ​​the vent and dynamically adjusting the gas flow rate of the vent in different areas to improve etching uniformity. The vent opening / closing actuator includes a vent baffle movable relative to the vent. The vent baffle is made of Kovar alloy or titanium alloy with a coefficient of thermal expansion matching that of the ceramic substrate, and a flexible sealing layer is provided between the vent baffle and the lower surface of the ceramic substrate. The vent baffle is configured to perform independent micron-level displacement relative to the lower surface of the ceramic substrate according to the control command to change the effective flow area of ​​the corresponding vent, thereby achieving independent control of the opening / closing state and opening degree of the vent in the corresponding area.

2. The controllable non-uniform ceramic plate air outlet system according to claim 1, wherein, The ceramic substrate has a double-layer structure, including an upper ceramic plate and a lower ceramic plate joined to the upper ceramic plate. Grooves are formed between the upper ceramic plate and the lower ceramic plate by etching or grinding, and the grooves are configured as independent gas flow channel partitions.

3. The controllable non-uniform ceramic plate air outlet system according to claim 2, wherein, The gas flow channel partitions are symmetrically distributed radially or in a fan shape around the center of the ceramic substrate. Each partition is connected to an independent air intake source or connected to the main air intake source through an adjustable valve group located upstream of the substrate.

4. The controllable non-uniform ceramic plate air outlet system according to claim 1, wherein, The shape of the air vent baffle is fan-shaped, rectangular, circular, or an irregular structure that matches the shape of the flow channel partition; And / or, the vent opening and closing actuator includes a miniature linear motor, a piezoelectric ceramic driver, or a voice coil motor; And / or, the pore opening and closing actuator includes a connecting rod to transmit the action within the ceramic matrix, the connecting rod being a rigid connecting rod, a flexible hinge, or a bellows structure.

5. The controllable non-uniform ceramic plate air outlet system of claim 1, wherein, The material is Kovar alloy, titanium alloy, or a metal material with a ceramic coating on the surface; And / or, the flexible sealing layer is a polyimide film or a metal corrugated gasket.

6. The controllable non-uniform ceramic plate air outlet system of claim 1, wherein, The control unit is configured to execute one or more of the following control procedures: S1: Receive real-time erosion depth data D(x,y,t) from the detection module, where (x,y) are the coordinates of the detection point and t is the time. S2: Calculate the etching uniformity index U value of the wafer surface at the current moment, where the index U value is the standard deviation or range value of the depth values ​​of all detection points; S3: Compare the index U value with a preset threshold U0. If U>U0, it is determined that the uniformity does not meet the standard, and step S4 is executed. S4: Analyze the spatial distribution of depth data D to identify areas with excessively slow and excessively fast etching rates; S5: Based on the recognition results, generate control instructions: increase the opening of the vent above the area with slow etching, and / or decrease the opening of the vent above the area with fast etching. S6: Send a control command to the vent opening / closing actuator to perform a fine-tuning action that changes the effective flow area of ​​the vent.

7. The controllable non-uniform ceramic plate air outlet system of claim 1, wherein, The control unit has a pre-stored process model, which has a preset mapping relationship between the etching depth distribution and the opening and closing state of the vent. The generation of the control command is based on the process model and combines feedforward control and closed-loop feedback control.

8. The controllable non-uniform ceramic plate air outlet system according to claim 7, wherein, The process model is a neural network model trained based on machine learning algorithms. Its inputs include historical etching depth data, current process parameters, and vent status, and its output is optimized vent control commands.

9. The controllable non-uniform ceramic plate air outlet system according to any one of claims 1-8, wherein, The detection module is an interference endpoint detection device, which includes a broadband light source, a beam splitter, a reference mirror and a spectrometer. The interference endpoint detection device measures the wafer surface through an optical window set at the top of the process chamber and calculates the etching depth by analyzing the interference spectrum of the reflected light and the reference light. And / or, the vent holes are non-uniformly distributed on the lower surface of the ceramic substrate, with a higher vent hole density and / or a larger vent hole diameter in areas where the expected etching rate is slower; And / or, the controllable non-uniform ceramic plate gas outlet system further includes a pressure sensor array, which is disposed in each of the gas flow channel partitions to monitor the real-time pressure of each partition. The control unit is also configured to adjust the vent opening and closing actuator and / or the intake valve according to the monitored pressure data to achieve coordinated control of flow rate and pressure.

10. A method of gas flow control based on the system of any one of claims 1-9, characterized by, include: The etching depth distribution on the wafer surface is monitored in real time using a detection module. Based on the etching depth distribution, determine whether the etching uniformity deviates from expectations; If the deviation from the expected behavior is detected, the vent opening and closing actuator is controlled to adjust the vent opening and closing status, thereby changing the gas flow rate of the vent in the corresponding area, thus correcting the spatial distribution of the reacting gas in the chamber and improving the uniformity of plasma density.

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