A double-cavity wafer full-automatic processing glue removing system

Abstract

The application discloses a double-cavity wafer full-automatic processing glue removing system, which comprises a first process cavity and a second process cavity which are sealed and isolated from each other, a vacuum system, a plasma generating system, a temperature control system and a gas path system are independently arranged in each cavity, and a control system. The control system controls the two cavities to perform different glue removing processes, and a pressure difference of 5 Pa to 500 Pa is formed by adjusting the vacuum pumping speed and / or the gas inlet flow. Based on the pressure difference, the two cavities exchange gas through a gas pressure balance channel, drive the airflow to flow from the high-pressure side to the low-pressure side, carry the suspended particulate matter on the high-pressure side to the low-pressure side, and discharge the suspended particulate matter with the exhaust system. When the gas pressure balance channel is closed, the two cavities are sealed and isolated, and when the gas pressure balance channel is opened, the two cavities are selectively connected. The application converts the pressure difference generated by the different processes into a driving force for removing particles, and realizes continuous particle removal without interrupting the process and without adding additional equipment.

Description

Technical Field

[0001] This application relates to the field of semiconductor manufacturing equipment technology, and in particular to a dual-cavity fully automated wafer processing adhesive removal system. Background Technology

[0002] In semiconductor manufacturing processes, photoresist removal is a critical step. Plasma photoresist removal technology has become the mainstream method due to its high efficiency and cleanliness. During plasma photoresist removal, the photoresist reacts with the plasma, producing residual photoresist particles and polymer debris. If these suspended particles deposit on the wafer surface, they will directly affect the yield of subsequent processes.

[0003] To increase production capacity, dual-chamber degumming equipment has emerged in existing technologies. This equipment employs parallel operation of two chambers, each running its own degumming process formulation independently. Since the process stages of the two chambers are typically asynchronous—one chamber may be in the degumming stabilization phase while the other is in the vacuum recovery phase—this asynchronous operation naturally leads to a pressure difference between the two chambers. However, in existing technologies, this pressure difference is considered a process disturbance, requiring adjustment through independent vacuum systems for each chamber to maintain process stability, rather than being recognized as a driving force for particle removal.

[0004] In existing technologies, particle removal within the chambers primarily relies on the chamber's own exhaust system. However, for fine particles suspended in the process space (especially those larger than 0.1 μm), the removal efficiency of the chamber's exhaust system alone is limited. When the particle concentration within the chamber exceeds the standard, traditional methods require interrupting the current degumming process, opening the chamber for manual cleaning, or introducing an external purging air source for forced removal. The former leads to process interruption and production loss, while the latter requires additional air source equipment and pipelines, increasing equipment complexity and modification costs.

[0005] Furthermore, during wafer transfer, if there is a large pressure difference between the cavity and the transfer cavity, directly opening the sealing door may damage the seal or cause particles to splash. Relying on the vacuum system or gas path system of a single cavity for pressure regulation is time-consuming and can easily cause system overload.

[0006] Therefore, there is an urgent need for a dual-chamber wafer desmearing system that can achieve continuous particle removal without interrupting the process or adding extra equipment, while also taking into account the pressure pre-adjustment before wafer transfer. Summary of the Invention

[0007] This application provides a dual-cavity fully automated wafer de-resin system, which aims to solve the technical problems in existing dual-cavity de-resin equipment, such as pressure difference caused by asynchronous process operation being regarded as an interference factor, the need to interrupt the process or add additional equipment for particle removal, and low efficiency of pressure regulation before wafer transfer.

[0008] The unit of measurement for particle concentration in this application, "particles per cubic foot," is a common unit for environmental monitoring in semiconductor cleanrooms.

[0009] To achieve the above objectives, this application adopts the following technical solution: A dual-cavity fully automated wafer processing resist removal system includes a first process cavity and a second process cavity, which are sealed and isolated from each other. Each cavity is independently equipped with a vacuum system, a plasma generation system, a temperature control system, and a gas path system to support the independent execution of their respective resist removal process formulas. A control system is also included, which is communicatively connected to the first process cavity and the second process cavity.

[0010] The control system is configured to: control the first process chamber to perform a first degumming process and control the second process chamber to perform a second degumming process, wherein the first degumming process and the second degumming process are asynchronous in their process stages, and by controlling the vacuum pumping speed and / or air intake flow rate of the two chambers, a pressure difference is formed between the first process chamber and the second process chamber, wherein the pressure difference ranges from 5 Pa to 500 Pa; and, based on the pressure difference, control the first process chamber and the second process chamber to exchange gases through a preset pressure balance channel, using the pressure difference to drive the airflow to flow directionally from the high-pressure side chamber to the low-pressure side chamber, carrying the particulate matter suspended in the high-pressure side chamber to the low-pressure side chamber and discharging it with the exhaust system of the low-pressure side chamber; wherein, when the pressure balance channel is closed, the process spaces of the first process chamber and the second process chamber are sealed and isolated from each other; when the pressure balance channel is open, the first process chamber and the second process chamber are selectively connected through the pressure balance channel.

[0011] Optionally, the pressure balancing channel includes a bypass pipe connecting the first process chamber and the second process chamber, with both ends of the bypass pipe communicating with the process spaces of the two chambers respectively, and a control valve disposed on the bypass pipe; the control valve is communicatively connected to the control system, and the control system adjusts the gas flow rate of the pressure balancing channel by controlling the opening degree of the control valve.

[0012] Optionally, the control system is configured to: acquire a first current pressure value of the first process chamber and a second current pressure value of the second process chamber, and calculate the pressure difference between the first current pressure value and the second current pressure value; when the pressure difference value is greater than a preset pressure difference threshold, open the control valve to allow gas to flow from the chamber on the higher pressure side to the chamber on the lower pressure side through the bypass pipeline; the pressure difference threshold is set according to the pressure difference range, generally taking 20% ​​to 50% of the lower limit of the pressure difference range, i.e., 1 Pa to 25 Pa, preferably 5 Pa to 10 Pa.

[0013] Optionally, the system further includes a particle detection sensor disposed in the first process chamber and / or the second process chamber, the particle detection sensor being communicatively connected to the control system; the control system is further configured to: determine, based on the detection signal from the particle detection sensor, whether the particle concentration in the first process chamber and the second process chamber exceeds a preset particle concentration threshold; if the particle concentration in either chamber exceeds the threshold, then execute the opening operation of the control valve.

[0014] Optionally, the system further includes an automatic transfer unit for transferring the wafer to the first process cavity or the second process cavity; the control system is further configured to: before the automatic transfer unit performs the wafer transfer operation, obtain the current particle concentration value of the cavity to be operated based on the detection signal of the particle detection sensor; if the current particle concentration value exceeds a preset wafer transfer particle concentration threshold, then delay the wafer transfer operation until the current particle concentration value drops below the wafer transfer particle concentration threshold after the control system performs the opening operation of the control valve; wherein, the wafer transfer particle concentration threshold is lower than the particle concentration threshold.

[0015] Optionally, the control valve is a normally closed valve; the control system is configured to: keep the control valve closed when both the first process chamber and the second process chamber are in the degumming process execution state, so that the first process chamber and the second process chamber are sealed and isolated from each other; when the pressure difference is greater than the pressure difference threshold and the current particle concentration in the chamber exceeds the particle concentration threshold, the control system sends an opening command to the control valve to execute the normal cleaning mode; when the pressure difference is greater than the pressure difference threshold and the current particle concentration in the chamber does not exceed the particle concentration threshold but is within the range of 30% to 80% of the particle concentration threshold, the control system sends an opening command to the control valve according to a preset low concentration cleaning strategy; when the pressure difference is greater than the pressure difference threshold but the current particle concentration in the chamber is less than 30% of the particle concentration threshold, the control system keeps the control valve closed.

[0016] The 30% and 80% thresholds were determined based on the following experimental statistics: Data was recorded throughout multiple process runs, showing the particle concentration rising from the background level to exceeding the process threshold. Analysis indicated that when the particle concentration was below the 30% threshold, the passive removal rate from natural settling and the cavity's own exhaust system was sufficient to maintain concentration stability, and the benefits of active removal were not significant. When the particle concentration exceeded the 80% threshold, its growth rate accelerated significantly, approaching the trigger boundary of conventional removal conditions, and the effective window for low-concentration removal strategies narrowed. Therefore, the 30% to 80% range was defined as the effective operating window for preventative removal.

[0017] Optionally, the control system is further configured to: when formulating the process recipes for the first degumming process and the second degumming process, set a pressure difference formation stage in the process steps of the first degumming process and the second degumming process according to a preset particle removal cycle; in the pressure difference formation stage, control the first process chamber and the second process chamber to run to different target pressure values ​​respectively, so that the target pressure difference between the two chambers is in the range of 5Pa to 500Pa, preferably 20Pa to 100Pa, so as to actively establish the pressure difference.

[0018] Optionally, the control system is further configured to: automatically execute a cavity self-cleaning procedure after the first process cavity or the second process cavity completes a batch of wafer resist removal process and before loading the next batch of wafers; the cavity self-cleaning procedure includes: controlling the cavity to be cleaned to enter a first pressure state, and simultaneously controlling another cavity to enter a second pressure state, so that a first pressure difference is formed between the two cavities; opening the pressure balance channel, and using the first pressure difference to drive the airflow to carry the particulate matter deposited in the cavity to be cleaned to the other cavity; closing the pressure balance channel, and controlling the other cavity to discharge the gas carrying the particulate matter through its independent exhaust system; repeating the above steps at least once, wherein before each repetition, controlling the other cavity to perform exhaust cleaning through its independent exhaust system; or, alternately switching the roles of the cavity to be cleaned and the other cavity, so that the two cavities are each other's cavity to be cleaned; the self-cleaning procedure is only executed when the other cavity does not carry wafers and does not perform resist removal process.

[0019] Optionally, the system further includes a transfer chamber, connected to the first process chamber and the second process chamber respectively via an openable sealing door, for transferring wafers between the first process chamber, the second process chamber, and the outside; the control system is further configured to: before performing a wafer transfer operation between any process chamber and the transfer chamber: obtain the current particle concentration value of the chamber to be opened, and determine whether the current particle concentration value is lower than a preset wafer transfer threshold; when the current particle concentration value is lower than the wafer transfer threshold, obtain the current chamber pressure value of the chamber to be opened and the current transfer chamber pressure value of the transfer chamber; when the current chamber pressure value is higher than the current transfer chamber pressure value, before opening the sealing door, when the other process chamber has not performed a desizing process and is in a low-pressure state, activate the pressure balancing mechanism. The channel connects the cavity to be opened to the other process cavity. The low-pressure environment of the other process cavity pre-lowers the pressure of the cavity to be opened to a level less than the pressure difference between it and the transmission cavity, thus reducing the pressure to a preset door opening threshold. When the current cavity pressure is lower than the current transmission cavity pressure, before opening the sealing door, process gas is introduced into the cavity to be opened through its independent gas path system. Simultaneously, the pressure balancing channel is opened to divert excess gas through the exhaust system of the other process cavity. The flow rate of the excess gas does not exceed 30% of the rated processing flow rate of the exhaust system of the other process cavity, pre-raising the pressure of the cavity to be opened to a level less than the preset door opening threshold. The sealing door is opened only when the pressure difference between the cavity to be opened and the transmission cavity is less than the preset door opening threshold to perform wafer transfer.

[0020] Optionally, the control system is further configured to: acquire particle size distribution information of particles detected by the particle detection sensor; divide the particles into at least two particle size classes according to the particle size distribution information; and, based on the settling characteristic parameters and airflow carrying difficulty parameters of each particle size class, call the preset cleaning strategy parameters corresponding to the particle size class from a preset cleaning strategy rule table to perform self-cleaning; wherein, when the actual process pressure difference differs from the calibrated pressure difference in the cleaning strategy rule table, the opening duration is adjusted according to the proportion of the minimum pressure difference driving force; the cleaning strategy rule table contains parameters corresponding to each particle size class. The preset pressure balance channel opening duration, opening frequency, and / or the opening degree of the control valve; the purging strategy rule table is calibrated under standard operating conditions, which are a pressure difference of 100 Pa, an oxygen environment, and a temperature of 25 °C; the settling characteristic parameters include the settling velocity of particles in the process gas; the airflow carrying difficulty parameters include the minimum pressure difference driving force required to suspend particles; the minimum pressure difference driving force refers to the minimum pressure difference value at which the drag force corresponding to the average airflow velocity generated in the bypass pipeline under the pressure difference condition is sufficient to overcome the sum of the effective gravity of the particles and the adhesion force to the wall.

[0021] The core inventive concept of this application is to redefine the pressure difference, which is traditionally regarded as a disturbance factor due to asynchronous operation of the process in the dual-chamber degumming equipment, as a beneficial driving force for particle removal, and to realize the controllable utilization of this driving force through selectively connected air pressure balance channels.

[0022] Compared with the prior art, the beneficial effects of the present invention are: This application utilizes the pressure difference naturally formed by the asynchronous operation of the dual-chamber process to achieve directional gas exchange between the two chambers through a pressure balance channel. Suspended particulate matter in the high-pressure side chamber is carried to the low-pressure side and discharged with the exhaust system. This allows for continuous removal of particles without interrupting the process or adding additional gas sources or extraction devices, avoiding production capacity loss due to downtime for cleaning. It also eliminates the need for external purging gas sources and their associated pipelines, reducing equipment complexity and modification costs.

[0023] This application enables the system to not only passively utilize the naturally formed pressure difference when the two chamber process stages are not synchronized, but also to actively create removal conditions when the process stages are synchronized or the pressure difference is insufficient. This breaks through the dependence of traditional technology on process timing and expands the applicable scenarios and flexibility of particle removal strategies.

[0024] This application reuses the air pressure balancing channel for pressure pre-adjustment before film transfer, enabling the system to quickly complete pressure balancing by means of the low-pressure environment of another chamber or the exhaust system without adding additional pressure adjustment equipment. This shortens the pressure adjustment time, improves film transfer efficiency, and avoids overload operation of a single system, realizing the multi-purpose and functional reuse of the air pressure balancing channel.

[0025] This application establishes a removal strategy rule table based on particle size classification, enabling the system to adopt differentiated removal strategies for different types of particles. This overcomes the shortcomings of traditional fixed-parameter removal methods, which have inconsistent removal efficiency for particles of different sizes, and achieves refined and standardized particle removal. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the system framework structure of the present invention. Detailed Implementation

[0027] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] In semiconductor resist stripping processes, the reaction between plasma and photoresist produces residual particles and polymer debris. Once these particles deposit on the wafer surface, the yield of subsequent processes is directly affected. While existing dual-chamber resist stripping equipment improves throughput through parallel operation, the process stages are often asynchronous when the two chambers operate independently with their respective formulations. For example, while one chamber is still stabilizing resist stripping, the other chamber has already entered vacuum recovery mode. This asynchrony naturally creates a pressure difference between the two chambers, and current technology has always treated this pressure difference as a disturbance factor, relying on independent vacuum systems to regulate the balance, without ever considering whether it could be utilized.

[0029] Traditionally, cavity particle removal either involves interrupting the process for manual cleaning or adding an external purging air source. The former results in reduced production capacity, while the latter increases equipment complexity. Furthermore, if the pressure difference between the cavity and the transfer cavity is too large during wafer transfer, directly opening the door may damage the seals or cause particle splashing. Relying on the vacuum system of a single cavity for pressure regulation is time-consuming and prone to overload.

[0030] The core idea of ​​this application is to redefine the pressure difference generated by the asynchronous operation of the two chambers from a "disturbing factor" to a "purge driving force," and utilize it through a controllable pressure balancing channel. Under this approach, the system can operate on four levels: passively utilizing natural pressure differences for continuous purging; actively setting a pressure difference formation stage in the formulation; reusing the pressure balancing channel for pre-adjustment of pressure before transfer; and establishing a standardized purging strategy based on particle size classification. These four levels work together to form a complete particle purging and pressure management system.

[0031] Let me first explain the system components. The "Gas System" includes the inlet, mass flow controller, and connecting pipelines; the "Vacuum System" includes the dry vacuum pump, molecular pump, vacuum gauge, and connecting pipelines; the "Exhaust System" is the part of the vacuum system that exhausts gas to the plant end, including the pipelines and valves after the molecular pump outlet; the "Plasma Generation System" includes the RF power supply, matching unit, and gas distribution plate. This distribution plate is responsible for both plasma uniform distribution and process gas distribution, so it is connected to the pipelines of the gas system; the "Temperature Control System" consists of the heater and cooling circuit, maintaining the chamber temperature within the process set range. "Low-pressure state" refers to a chamber pressure below 50 Pa, used in the pressure pre-adjustment process before wafer transfer to determine whether the other chamber can serve as the low-pressure side to receive the split gas. Each subsystem is connected to the control system through an independent control interface, allowing the two chambers to run their respective recipes without interference.

[0032] The control system comprises an industrial control computer (IPC), a programmable logic controller (PLC), analog input / output modules, digital input / output modules, a communication interface module, and a human-machine interface (HMI). The IPC acts as the host computer, running software programs for five functional modules: process scheduling, differential pressure management, particle monitoring, valve control, and recipe management. The PLC acts as the slave computer, directly connecting to the sensors and actuators of each subsystem, executing control commands issued by the IPC, and providing real-time status feedback. The analog input / output modules acquire analog signals from vacuum gauges, particle detection sensors, and temperature sensors, and output analog control signals to the mass flow controller and vacuum pump frequency converter. The digital input / output modules control the opening and closing of valves, the opening and closing of sealing doors, and the start / stop switches of each subsystem. The communication interface module enables bidirectional communication between the IPC and the PLC, and between the IPC and the host plant management system, via Ethernet or RS-485 bus. The HMI is a touchscreen display, allowing operators to set process parameters, view real-time status, and receive alarm information. The aforementioned hardware architecture enables the control system to establish communication connections with each subsystem of the first and second process chambers simultaneously, achieving independent control and collaborative management of the two chambers.

[0033] The first and second process chambers can have the same structure or be configured differently according to process requirements. Each chamber contains a wafer support stage, plasma generation electrode, gas inlet, gas outlet, and temperature control device. The vacuum system consists of a dry vacuum pump and a molecular pump connected in series. The dry vacuum pump has a pumping speed range of 500 L / min to 2000 L / min (preferably 1000 L / min) and an ultimate vacuum below 0.1 Pa; the molecular pump has a pumping speed range of 300 L / s to 1000 L / s (preferably 500 L / s) and an ultimate vacuum below 1 × 10⁻⁶ Pa. -4 Pa; precise pressure control is achieved using a vacuum gauge with an accuracy of ±1 Pa. The plasma generation system produces oxygen or fluorine-based plasma, with an RF power supply ranging from 500W to 3000W at a frequency of 13.56MHz, and an auto-tuning adapter. The temperature control system maintains a temperature between 150°C and 300°C. The gas supply system introduces oxygen, nitrogen, or fluorine-containing process gases into the chamber via a mass flow controller with a range of 10 sccm to 5000 sccm and an accuracy of ±1% of full scale. Each subsystem is independently connected to the control system, and the two chambers do not interfere with each other.

[0034] The pressure balancing channel is crucial to this system. In existing dual-chamber systems, the two chamber process spaces are strictly sealed and isolated, and any gas exchange between the chambers is considered a risk of cross-contamination. This application breaks with this conventional thinking by setting a controllable pressure balancing channel between the two chambers. This channel is normally closed by default and selectively opens only when specific pressure difference and particle concentration conditions are met, allowing directional gas flow to carry particles. The pressure balancing channel includes a bypass pipe and control valves. The bypass pipe connects to the process spaces of the two chambers at both ends, and a control valve is installed on the pipe. The inner diameter is generally 10mm to 50mm, preferably 20mm to 30mm, balancing flow capacity and compact structure. The axial length is 200mm to 800mm, preferably 300mm to 500mm. The material is stainless steel or anodized aluminum alloy, and the inner wall roughness Ra is controlled below 0.8μm to reduce secondary particle deposition. The control valves are normally closed by default, ensuring the process spaces of the two chambers are sealed and isolated. The sealing interface uses metal sealing rings or fluororubber O-rings, and the leakage rate between the two chambers is less than 1×10 when the valve is closed. -9 Pa·m³ / s. Select a pneumatic or electric driven vacuum valve, with continuous adjustment of opening from 0% to 100% and a response time not exceeding 2 seconds.

[0035] Selective connectivity is achieved through the following control logic: The control system continuously monitors the pressure difference and particle concentration between the two chambers. Only when both conditions are met—"pressure difference greater than the pressure difference threshold" and "particle concentration meeting the corresponding removal conditions"—is an opening command sent to the control valve. If either condition is not met, the control valve remains closed. This judgment logic is executed by software in the industrial control computer, and the PLC outputs a digital signal to drive the control valve based on the judgment result. Therefore, the opening of the pressure balance channel is not unconditional, but rather a selective decision based on real-time operating data, ensuring that the two chambers are only briefly connected when particle removal requirements are met, remaining sealed and isolated at other times.

[0036] This section requires a detailed explanation of the mechanism by which directional airflow is achieved. While the description above states "directional flow from the high-pressure side to the low-pressure side," this is not actually achieved through a mechanical structure like a one-way valve, but rather through the coordination of control logic and system design. Specifically, achieving directional flow requires the simultaneous fulfillment of the following four conditions: First, the valve opening is strictly limited to a "pressure difference greater than a threshold." It only opens when a clear pressure difference exists, thus determining the initial direction. The pressure difference threshold is set between 5 Pa and 10 Pa, which is much higher than the typical range of pressure fluctuations in a vacuum system (±1 Pa to ±2 Pa), ensuring that it will not be falsely triggered due to random fluctuations.

[0037] Second, after the valve opens, the control system continuously monitors the real-time pressure of the two chambers at a cycle of 100 to 500 milliseconds. Once the pressure difference drops below half of the threshold (for example, if the threshold is 5 Pa and the pressure difference drops below 2.5 Pa), the valve is immediately closed. This "half-threshold shut-off" mechanism ensures that the connection is cut off before the pressure difference may reverse. Assuming a valve response time of 2 seconds and a maximum pressure change rate of 5 Pa / second, from the time the pressure difference drops to 2.5 Pa until the valve is fully closed, the pressure difference may change by a maximum of 10 Pa. During this time, the pressure on the high-pressure side remains higher than that on the low-pressure side, preventing backflow.

[0038] Third, the bypass pipe interfaces on the cavity are all connected to the upper part of the cavity, 50mm to 100mm above the wafer carrier. Particles settle naturally under gravity. Even with minor pressure fluctuations, particles already carried to the low-pressure side are directly discharged by the continuous suction from the low-pressure side exhaust system because they are located in the upper airflow channel of the cavity, making it difficult for them to flow back to the high-pressure side. The low-pressure side exhaust system maintains its rated pumping speed during valve opening, keeping the low-pressure side pressure stable and creating a continuous suction effect.

[0039] Fourth, the low-pressure side exhaust system operates continuously during valve opening, constantly removing the inflowing gas to maintain a low-pressure state. The exhaust system's pumping speed is designed to be 3 to 5 times the maximum flow rate of the bypass line. This ratio is determined based on the cavity volume and the exhaust system's rated pumping speed to ensure that the inflowing gas does not cause a significant increase in low-pressure side pressure, thus weakening the pressure differential driving force. Taking this embodiment as an example, the maximum flow rate of the bypass line at a pressure differential of 40 Pa is approximately 1.7 × 10⁻⁶. - The rated pumping speed of the exhaust system is 1000 L / s (equivalent to 60000 L / min), which is about 588 times the maximum flow rate of the bypass pipeline and far exceeds 3 times the lower limit. Therefore, the system has sufficient margin for stable operation.

[0040] When these four conditions are combined, it ensures that the airflow flows directionally from the high-pressure side to the low-pressure side during valve opening, carrying suspended particles with it and expelling them with the exhaust gas. This is a controllable directional flow driven by pressure difference, with the direction determined by the real-time pressure difference. A monitoring-shutdown mechanism cuts off the connection before the pressure difference can reverse, preventing backflow.

[0041] To verify the effectiveness of the aforementioned directional flow, the following experiment was conducted: The experimental conditions were: a pressure of 50 Pa in the first process chamber, a pressure of 10 Pa in the second process chamber, and a pressure difference of 40 Pa; the bypass pipeline had an inner diameter of 25 mm and a length of 400 mm; the control valve was opened at 70% for 60 seconds. Before the experiment, a known concentration of residual polystyrene standard photoresist particles (0.5 μm in diameter, 1000 particles / cubic foot) was introduced into the first process chamber via an aerosol generator. The valve was opened after the particles were evenly distributed. During the experiment, particle sampling points were set at the middle section of the bypass pipeline, the exhaust port of the first chamber, and the exhaust port of the second chamber. The experimental results are as follows: 10 seconds after the valve was opened, the particle concentration in the middle section of the bypass pipeline reached a peak of 850 particles / cubic foot; at 30 seconds, the particle concentration at the exhaust port of the first chamber dropped to 120 particles / cubic foot; and at 60 seconds when the valve was closed, the particle concentration in the first chamber dropped to 80 particles / cubic foot, below the process threshold. The particle concentration in the first chamber was measured at 5, 15, and 30 seconds after the valve was closed, and was 82, 85, and 83 particles / foot, respectively. The relative variation was less than ±5%, indicating no significant backflow. The second chamber continuously discharged particulate-containing gas from its vent while the valve was open. After 90 seconds of venting, the particle concentration in the second chamber returned to background levels (<20 particles / foot). The experiment was repeated three times, and the results showed good consistency with a relative standard deviation of less than 8%.

[0042] The control system comprises several modules: process scheduling, differential pressure management, particle monitoring, valve control, and formulation management. The process scheduling module coordinates the timing of the two chambers, allowing the first and second process chambers to run the first and second debinding processes, respectively. The two chambers typically operate at different times; for example, the first chamber may be in the plasma debinding stabilization phase while the second chamber is in the vacuuming or gas-filling recovery phase. The pressure states differ at different stages, and the control system adjusts the vacuum pump speed and / or gas flow rate of the two chambers to establish a stable pressure difference. The pressure difference is controlled within the range of 5 Pa to 500 Pa, preferably 20 Pa to 100 Pa, and more preferably 30 Pa to 50 Pa.

[0043] This range is determined based on both theoretical and experimental evidence. For bypass pipes with an inner diameter D of 20mm to 30mm and a length L of 300mm to 500mm, the gas velocity under a pressure difference of 5Pa to 500Pa can be estimated as follows: Simplifying the bypass pipe as a circular pipe with a uniform cross-section, in the continuous flow region where the Knudsen number Kn < 0.01 (the mean free path of oxygen molecules at room temperature is approximately 0.1μm, and the hydraulic diameter of the pipe is much larger than this value), according to the Poiseuille flow correction model, the volumetric flow rate Qv and the pressure difference ΔP satisfy the following: Qv=(π·D 4 ·ΔP) / (128·η·L)·Cslip; η is the dynamic viscosity of the process gas (approximately 2.0 × 10⁻⁶ for oxygen at 25°C).-5 Pa·s), Cslip is the slip correction factor, taken as 1.2 to 1.5 under low pressure. Average airflow velocity v = Qv / (π·D² / 4). With D = 10 mm, L = 400 mm, ΔP = 40 Pa, η = 2.0 × 10⁻⁶ Pa·s, and η = 2.0 × 10⁻⁶ Pa·s, the following conditions are met: - 5 Taking Pa·s and Cslip = 1.3 as an example, Qv ≈ 1.6 × 10 - ³m³ / s (approximately 96 L / min), v≈20 m / s.

[0044] It should be noted that the Poiseuille formula calculation results mentioned above are theoretical estimates. The actual airflow velocity in the bypass pipeline is affected by valve opening, local pipeline resistance (such as elbows and joints), and non-ideal flow effects, and the measured value is usually lower than the theoretical calculation value. Taking the bypass pipeline (D=25mm, L=400mm) actually used in this embodiment as an example, under the conditions of ΔP=40Pa and valve opening of 70%, the measured volumetric flow rate is approximately 1.7×10⁻⁶. - The measured flow rate was approximately 3.5 m / s (approximately 102 L / min), corresponding to an average measured airflow velocity of about 3.5 m / s. This measured value is comparable to the calculated flow rate of the theoretical model with a diameter of 10 mm, indicating that the equivalent flow capacity of a real pipe with a diameter of 25 mm is equivalent to that of an ideal circular pipe with a diameter of 10 mm due to valve throttling and local resistance. The airflow velocity in subsequent particle carryover analyses will be based on this measured value of 3.5 m / s.

[0045] The carrying conditions of particles in an airflow are determined by the balance of forces. Suspended particles are subject to gravity, gas drag force, and buoyancy. When the drag force is sufficient to overcome the sum of effective gravity and wall adhesion force, the particle can be carried away. The drag force of spherical particles is Fd = 3π·η·dp·vr, where dp is the particle diameter and vr is the relative velocity. The effective gravity is Fg = (π / 6)·dp³·(ρp-ρg)·g, where ρp is the particle density, which is taken as 1400 kg / m³ based on the measured value of the photoresist material used in this embodiment, and ρg is the gas density. The wall adhesion force Fa is related to the particle material, surface roughness, and contact time. The Fa of freshly deposited particles is usually less than Fg, while the Fa of long-term deposited particles may reach several to tens of times Fg.

[0046] When the pressure difference is below 5 Pa, with D=25 mm and L=400 mm, the velocity (v) is below 0.5 m / s. The drag force of particles larger than 0.1 μm is insufficient to overcome the effective gravity plus the wall adhesion force, and they cannot be carried away. When the pressure difference is above 500 Pa, v exceeds 35 m / s. The high-speed airflow may strip the particles already deposited on the cavity wall a second time, or cause brittle particles to collide and break at high speed, thus increasing the number of suspended particles. Under standard operating conditions (oxygen environment, 25℃, bypass pipe inner diameter 25 mm, length 400 mm), the particle removal effect was tested under pressure differences of 200 Pa, 300 Pa, 400 Pa, 500 Pa, and 600 Pa. The results show that at 500 Pa and below, there is no significant secondary stripping of particles deposited on the cavity wall, and the removal efficiency increases with the increase of pressure difference; at 600 Pa, some brittle particles break, and the number of suspended particles increases by about 5% compared to before removal. Therefore, 5Pa to 500Pa represents a balance between carrying efficiency and process safety, with 500Pa serving as the upper limit, as verified experimentally.

[0047] The differential pressure management module acquires the pressure values ​​of the two chambers in real time via a vacuum gauge and calculates the differential pressure. When the differential pressure exceeds a preset threshold, a differential pressure compliance signal is sent to the valve control module. The differential pressure threshold is set within the range of 5 Pa to 500 Pa, preferably 5 Pa to 10 Pa. The threshold setting must take into account the flow resistance of the bypass pipeline, the minimum particle carrying capacity, and the valve response delay. Too low a threshold (e.g., below 5 Pa) will cause the valve to open and close frequently due to pressure fluctuations, affecting its lifespan and stability; too high a threshold may miss the clearing opportunity. Here, the lower limit of the threshold and the lower limit of the differential pressure range are unified at 5 Pa to ensure timely triggering within the effective differential pressure range, while avoiding frequent opening and closing caused by an excessively low threshold.

[0048] The particle monitoring module receives signals from the particle detection sensor. The sensor can be a light-scattering particle counter or a laser particle counter, mounted near the exhaust port or above the wafer stage. In this embodiment, the sensor includes particle size distribution detection, utilizing the multi-channel light scattering principle to measure the light intensity distribution at different scattering angles, and then combining this with Mie scattering inversion to obtain the particle size distribution. The detection range is 0.1 μm to 10 μm, divided into three levels: large particles (>1 μm), medium particles (0.3 μm to 1 μm), and tiny particles (0.1 μm to 0.3 μm). The particle monitoring module determines whether the concentration in both chambers exceeds a threshold.

[0049] Definitions and relationships of the three types of concentration thresholds: The process threshold (also known as the particle concentration threshold) determines whether the particle concentration is normal during process execution. Particles larger than 0.1μm are set at 100 to 1000 particles / cubic foot, preferably 300 to 500. Exceeding this threshold triggers regular cleaning.

[0050] Transfer threshold – determines whether the cleanliness level meets the standard before transfer. Independent of the process threshold, the value is 50% to 80% of the process threshold, i.e., 50 to 800 pieces / cubic foot, preferably 200 to 300. Lower than the process threshold ensures a cleaner transfer environment.

[0051] Cleaning threshold – determines whether self-cleaning has achieved the expected results. 10% to 30% of the process threshold, i.e., 10 to 300 particles / cubic foot, preferably 50 to 150.

[0052] Relationship: Cleaning threshold < Transfer threshold < Process threshold. The highest requirements are placed after self-cleaning; the surface must be cleaner before transfer than during process operation; a relatively higher particle concentration is permissible during process operation to reduce unnecessary cleaning interference.

[0053] If the concentration in any chamber exceeds the process threshold, the particle monitoring module sends a particle exceeding the limit signal to the valve control module.

[0054] The valve control module uses signals from differential pressure management and particle monitoring to determine whether to open the valve. When both chambers are performing the degumming process, the valve remains closed to ensure a tight seal. When the differential pressure exceeds a threshold and the particle concentration exceeds the process threshold, the valve opens, allowing gas to flow from the high-pressure side to the low-pressure side via a bypass line. Suspended particles from the high-pressure side are carried to the low-pressure side and discharged with the exhaust gas.

[0055] When the differential pressure is greater than the threshold and the particle concentration is within 30% to 80% of the process threshold, a low-concentration purge strategy is executed. In this case, the system determines that although the particle concentration is not exceeding the limit, there is a tendency for accumulation, and preventative purge is initiated. The criteria for the low-concentration purge strategy are: when the particle concentration is within 30% to 80% of the process threshold and the differential pressure is greater than the threshold, preventative purge is triggered. The activation duration is 30% to 50% of the normal mode (30 to 120 seconds for normal, 10 to 60 seconds for low concentration), the valve opening is 20% to 40% (50% to 80% for normal), and the frequency is once every 10 to 30 minutes. The low-concentration strategy reduces gas exchange and low-pressure side exhaust load while maintaining cleanliness, avoiding process disturbance and energy waste caused by excessive purge when the particle concentration is low.

[0056] During low-concentration purges, will the inflow of high-pressure side gas (which may contain process gases and reaction byproducts) into the low-pressure side contaminate the low-pressure side process environment? Experiments have verified that under conditions of valve opening 20% ​​to 40% and opening duration 10 to 60 seconds, the total amount of gas flowing into the low-pressure side accounts for 5% to 15% of the low-pressure side cavity volume. Furthermore, after the particle concentration in the inflowing gas is removed by the low-pressure side exhaust system, its impact on the original particle concentration on the low-pressure side is less than 10%. This impact is within the allowable fluctuation range of the process and will not significantly deteriorate the low-pressure side environment. Moreover, the trigger frequency of the low-concentration strategy (once every 10 to 30 minutes) is far lower than the conventional mode, and the cumulative interference on the low-pressure side is also limited. Therefore, the low-concentration strategy achieves preventative purges while maintaining a controllable impact on the low-pressure side process.

[0057] When the particle concentration is below 30% of the process threshold, the valve will not be opened even if the differential pressure meets the standard, in order to avoid unnecessary process disturbance.

[0058] Particle removal process during operation: After the control system starts the two-chamber degumming process, the differential pressure management module acquires the pressure value in real time and calculates the differential pressure. When the differential pressure is greater than the threshold, the particle concentration is further determined. If the particle concentration exceeds the process threshold, the valve is opened in the normal mode for removal; if it does not exceed the threshold but is within the range of 30% to 80%, a low-concentration strategy is used to open the valve; if it is below 30%, the valve remains closed. During the removal process, the particle concentration is continuously monitored, and the valve is closed after it drops below the corresponding threshold. Differential pressure monitoring continues until the process is completed.

[0059] For a concrete example: The first process chamber undergoes oxygen plasma debinding, with the pressure stabilizing at 50 Pa. The second process chamber, having just completed the previous batch, is undergoing vacuum recovery, and the pressure drops to 10 Pa. The pressure difference between the two chambers is 40 Pa, exceeding the threshold of 5 Pa. The particle sensor measures a particle concentration of 600 particles / foot in the first chamber, exceeding the process threshold of 300. The valve control module issues an opening command, and the valve opens to 70%. Gas flows from the first chamber to the second chamber via a bypass pipe at a velocity of approximately 3.5 m / s, carrying away suspended particles larger than 0.1 μm. After 60 seconds, the particle concentration in the first chamber drops to 100, below the process threshold, and the valve closes. The second chamber then vents for 90 seconds via an independent exhaust system. Experiments have verified that, under the aforementioned conventional cleaning mode, the total amount of particulate-containing gas flowing into the second chamber accounts for 15% to 25% of the chamber's volume. After being removed by the exhaust system, the peak particle concentration in the second chamber does not exceed 20% of its original background concentration, and returns to the background level (<20 particles / cubic foot) within 90 seconds, having no significant impact on subsequent processes in the second chamber. Throughout the entire process, the resist removal process in the first chamber was not interrupted, and the wafer continued plasma treatment. The only brief pressure fluctuation was approximately ±5 Pa due to gas exchange, which was within the allowable range.

[0060] This is fundamentally different from existing technologies: existing technologies treat the pressure difference generated by the asynchronous operation of the two chambers as an interference factor to be eliminated, and rely on their respective exhaust systems to passively remove the particles; this application transforms this pressure difference into an active driving force for removal, and achieves directional gas exchange through the air pressure balance channel, bringing high-pressure side particles to the low-pressure side and discharging them with the existing exhaust. This allows for continuous removal during the process without adding any additional hardware, avoiding production capacity loss due to downtime for cleaning, and eliminating the need for additional external purging air sources and supporting pipelines.

[0061] Another example. The pressure in the first chamber is 55 Pa, and in the second chamber it is 15 Pa, with a pressure difference of 40 Pa, exceeding the threshold of 5 Pa. The particle concentration is 200 particles / foot, below the process threshold of 300, but within the range of 30% to 80% (between 90 and 240, with 200 falling within this range). The valve control module issues an opening command using a low-concentration strategy, opening the valve to 30% for 15 seconds. After this, the particle concentration drops to 150, and the valve closes. The low-concentration strategy reduces gas exchange and the load on the second chamber exhaust system.

[0062] During the formulation stage, the formulation management module sets a pressure differential formation stage in the two-chamber process steps according to a preset cleanup cycle. This is typically scheduled at specific time points during process step transitions or stabilization phases, such as every 5 to 15 minutes, preferably every 8 to 12 minutes. The pressure differential formation stage controls the two chambers to operate at different target pressures, ensuring a target pressure differential between 5 Pa and 500 Pa, preferably 20 Pa to 100 Pa. The target pressure setting must take into account the gas flow rate, vacuum pump speed, and chamber volume of the current process step. For example, the target pressure for the first chamber is 50 Pa, and for the second chamber, it is 20 Pa, with a target pressure differential of 30 Pa. The control system can establish the pressure differential through one or a combination of the following three methods: (1) Adjust the inlet flow rate of the mass flow controller separately, such as reducing the inlet flow rate of the first chamber from the standard 50 sccm to 20 sccm, while keeping the inlet flow rate of the second chamber unchanged; (2) Adjust the pumping speed of the vacuum pump separately, such as increasing the pumping speed of the second chamber vacuum pump from 500L / s to 800L / s, while keeping the pumping speed of the first chamber unchanged. (3) Combine the adjustment of the inlet air flow rate and the vacuum pump speed, such as simultaneously reducing the inlet air flow rate of the first chamber to 20 sccm and increasing the pump speed of the second chamber to 800 L / s. All three methods can enable the two chambers to reach their respective target pressures at the end of the pressure difference formation stage, actively establishing the required pressure difference. Individual adjustment is suitable for scenarios where only fine-tuning of the pressure difference is required, while combined adjustment is suitable for scenarios where a large pressure difference needs to be established quickly. The duration is generally 10 to 60 seconds, preferably 20 to 40 seconds, to ensure that the pressure reaches a stable state and to avoid pressure disturbances from significantly affecting the uniformity of adhesive removal. Experiments show that within the above duration range, the impact of pressure fluctuations on the uniformity of adhesive removal is less than ±3%, which is within the allowable range.

[0063] Specific example: The control system establishes a pressure differential formation stage between steps 3 and 4 of the first degumming process, lasting 30 seconds. The inlet air flow of the first chamber mass flow controller is reduced from the standard 50 sccm to 20 sccm, while the pumping speed of the second chamber vacuum pump is increased from 500 L / s to 800 L / s. After 30 seconds, the pressure in the first chamber stabilizes at 50 Pa, and in the second chamber at 20 Pa, forming the target pressure differential of 30 Pa. Then, the particle removal stage begins, with the valve opened at 60% for 20 seconds. After removal, the standard process parameters are restored, and subsequent steps continue.

[0064] After one batch of wafers has undergone resist removal and before the next batch is loaded, the control system automatically performs chamber self-cleaning. This procedure only runs when another chamber is not carrying wafers and is not undergoing resist removal, avoiding interference with ongoing processes. The control system selects the chamber to be cleaned and controls it to enter a first pressure state (relatively high pressure), while simultaneously controlling the other chamber to enter a second pressure state (relatively low pressure), creating a first pressure difference. The first pressure difference ranges from 5 Pa to 500 Pa, but the preferred value is higher than during process operation, from 50 Pa to 200 Pa, providing stronger airflow driving force.

[0065] For example, control the vacuum system of the chamber to be cleaned to reduce the pumping speed or stop pumping, while simultaneously introducing nitrogen or oxygen through the gas path at 10 sccm to 50 sccm to raise the pressure to 100 Pa to 300 Pa; control the vacuum system of the other chamber to operate at the rated pumping speed, and reduce the pressure to 10 Pa to 50 Pa; a pressure difference of 50 Pa to 200 Pa is formed between the two chambers, and the airflow flows directionally from the chamber to be cleaned to the other chamber, carrying the deposited particles there.

[0066] Then, the air pressure balance channel is opened, and the pressure difference is used to drive the airflow to carry the deposited particles in the cavity to be cleaned to another cavity.

[0067] Self-cleaning targets particles deposited on the cavity wall, which differs from the mechanism for removing suspended particles. Suspended particles can be carried away simply by overcoming gravity; deposited particles, in addition to gravity, must also overcome the adhesion force with the cavity wall. The adhesion force originates from van der Waals forces, capillary forces, and electrostatic forces, and is related to the particle material, surface roughness, contact time, and ambient humidity. The adhesion force Fa between residual photoresist particles deposited in the plasma photoresist removal environment and the stainless steel cavity wall can be estimated: Fa = k·dp, where k is the adhesion coefficient. Based on the characteristics of the photoresist material used in this embodiment and experimental measurements of the stainless steel surface roughness, the k value at the photoresist-stainless steel interface is within 10. -7 N / m to 10 -6 N / m. When dp=1μm, Fa is approximately 10. - ¹³N to 10 -¹²N. When the airflow drag force Fd = 3π·η·dp·v, and v = 10 m / s (corresponding to a pressure difference of approximately 200 Pa), Fd is approximately 2 × 10⁻⁶ N. - ¹²N is on the same order of magnitude as Fa. Therefore, self-cleaning uses a relatively high pressure difference of 50 Pa to 200 Pa to provide sufficient airflow velocity to overcome the adhesion of deposited particles. Long-term deposited particles with strong adhesion can be gradually removed by repeatedly performing self-cleaning or alternating between the two chambers.

[0068] Then close the pressure balance channel and control the other chamber to discharge the gas carrying particles through an independent exhaust system. The exhaust time is 30 to 120 seconds, preferably 60 to 90 seconds. If the particle concentration in the chamber to be cleaned does not drop below the cleaning threshold, control the other chamber to exhaust and clean first before each repetition, and then repeat. The number of repetitions generally does not exceed 3 times. If the concentration is still above the cleaning threshold after 3 repetitions, an alarm will be triggered to prompt manual inspection. Alternatively, the roles of the chamber to be cleaned and the other chamber can be switched alternately, with the two chambers cleaning each other in a bidirectional manner. The cleaning threshold is 10% to 30% of the process threshold, i.e., 10 to 300 particles / cubic foot, preferably 50 to 150.

[0069] How exactly does the role switching work? Round 1: The first chamber acts as the chamber to be cleaned, and the second chamber acts as the receiving chamber. The pressure in the first chamber rises to 200 Pa, and the pressure in the second chamber drops to 20 Pa, a pressure difference of 180 Pa. The pressure balancing channel is opened for 60 seconds to carry the deposited particles from the first chamber to the second chamber. The channel is closed, and the second chamber exhausts gas for 90 seconds. Then, the roles are switched: the second chamber becomes the new chamber to be cleaned, and the first chamber becomes the new receiving chamber. The pressure in the second chamber rises to 200 Pa, and the pressure in the first chamber drops to 20 Pa. The channel is opened again for 60 seconds to carry the particles from the second chamber to the first chamber. The channel is closed, and the first chamber exhausts gas for 90 seconds. These two rounds constitute a complete role switching cycle. Switching criteria: After the first round, if the particle concentration in the chamber to be cleaned (the first chamber) is still higher than the cleaning threshold, a switch is executed; if it is already lower, no switch is needed. A maximum of two role switching cycles (four rounds of operation) are performed. If any chamber still has a particle concentration higher than the cleaning threshold after four rounds, an alarm is triggered. This mechanism achieves mutual cleaning between the two chambers through bidirectional pressure difference drive, and is suitable for situations where both chambers have deposited particles and the cleaning efficiency in one direction is insufficient.

[0070] The system also includes a transfer chamber, which is connected to the first and second process chambers via openable sealed doors, for transferring wafers between the two process chambers and the outside. The pressure pre-adjustment process before wafer transfer is as follows: Before transferring wafers between any process chamber and transfer chamber, the control system first obtains the current particle concentration of the chamber to be opened and determines whether it is below the transfer threshold. The transfer threshold is used to determine whether the cleanliness of the chamber before transfer meets the conditions for opening the sealing door. Its value is 50% to 80% of the process threshold, i.e., 50 to 800 particles / cubic foot, preferably 200 to 300 particles / cubic foot. If it is below the transfer threshold, pressure pre-adjustment continues; otherwise, the particle removal procedure is initiated until the concentration reaches the target.

[0071] If the pressure in the chamber to be opened is higher than the pressure in the transmission chamber, before opening the door, determine whether the other process chamber has not undergone adhesive removal and is in a low-pressure state. If the condition is met, open the pressure balance channel to connect the chamber to be opened with the other chamber. Utilize the low-pressure environment of the other chamber to pre-reduce the pressure in the chamber to be opened until the pressure difference with the transmission chamber is less than the door opening threshold. The door opening threshold is determined based on the structural strength and sealing performance of the sealing door, generally 50Pa to 200Pa, preferably 80 to 120Pa. This threshold is determined as follows: calculate the force on the sealing door under pressure difference based on the sealing ring material (such as fluororubber or metal sealing ring), sealing surface width, and chamber volume; the door opening threshold is set to 10% to 20% of the maximum allowable pressure of the sealing ring to ensure that the sealing ring will not be squeezed out or damaged due to excessive pressure difference when opening. If the other chamber does not meet the low-pressure condition, directly evacuate and reduce the pressure through the vacuum system of the chamber to be opened until the pressure difference meets the requirements.

[0072] If the pressure of the chamber to be opened is lower than the pressure of the transmission chamber, process gas is introduced through the independent gas path system of the chamber to be opened before opening the door. At the same time, the pressure balance channel is opened so that the portion of the introduced gas that exceeds the requirement to maintain the target pressure is diverted and discharged through the exhaust system of another chamber.

[0073] Specifically, the control system uses the target pressure of the cavity to be opened (i.e., the transmission cavity pressure) as a benchmark to calculate the gas increment required to reach the target pressure. The inflation flow rate is precisely controlled by a mass flow controller, and the pressure of the cavity to be opened is continuously monitored during inflation. The control system uses the difference between the real-time pressure measurement and the target pressure as feedback, and adjusts the inflation flow rate of the mass flow controller through a feedback control algorithm to make the inflation rate proportional to the pressure difference. Inflation stops when the pressure difference is less than 20% of the door opening threshold. During this process, the pressure balance channel remains open, and the portion exceeding the instantaneous target pressure balance flows to another cavity in real time and is discharged through its exhaust system. This "diversion discharge" avoids overpressure in the cavity to be opened, while utilizing the exhaust capacity of the other cavity to accelerate pressure balance. The gas flow rate of the diverted discharge is controlled within 30% of the rated processing flow rate of the exhaust system of the other cavity.

[0074] This 30% limit is determined through the following experiment: select standard working conditions in the commissioning phase, the first chamber is the chamber to be opened (the target is to pre-rise from 10Pa to 100Pa), and the second chamber is the receiving chamber (initial pressure 20Pa, the rated processing flow of the exhaust system is 1000L / s). Test the split flow at 20%, 25%, 30%, 35%, and 40% of the rated processing flow respectively: At 20%, the pressure of the second chamber rises to 24Pa with a fluctuation within ±2Pa, and the system is stable; at 25%, the pressure of the second chamber rises to 28Pa with a fluctuation within ±3Pa, and the system is stable; at 30%, the pressure of the second chamber rises to 32Pa with a fluctuation within ±4Pa, the system is stable but close to the critical point; at 35%, the pressure of the second chamber rises to 38Pa with a fluctuation exceeding ±5Pa, triggering a protective warning of the vacuum system; at 40%, the pressure of the second chamber rises to 45Pa, and the vacuum system triggers a protective shutdown.

[0075] As can be seen from the data, 30% is the critical value that achieves the fastest pressure pre-adjustment efficiency on the premise of ensuring the stable operation of the vacuum system of the second chamber. Therefore, the upper limit of the split flow is set to 30% of the rated processing flow of the exhaust system of the other chamber.

[0076] The feedback control of the gas charging process is implemented in the following manner: the control system sets the target pressure Pt (the current pressure of the transfer chamber), measures the pressure P of the chamber to be opened in real time, and calculates the deviation e=Pt-P. The gas charging flow Q is regulated by a mass flow controller, and the regulation rules are: when e>50% of the door opening threshold, Q=Qmax (50% to 70% of the maximum flow of the mass flow controller); when 20% of the door opening threshold < e ≤ 50% of the door opening threshold, Q=Qmax·(e / (50% of the door opening threshold)); when e ≤ 20% of the door opening threshold, stop gas charging. This piecewise linear control strategy avoids the complexity of PID parameter tuning, and ensures the rapidity and stability of the gas charging process at the same time.

[0077] To verify the effectiveness of the above control strategy, the following experiment was carried out: the experimental conditions are that the first chamber (volume 80 liters) pre-rises from 10Pa to 100Pa, and the second chamber (exhaust system rated flow 1000L / s) has an initial pressure of 20Pa. The above piecewise linear control strategy is adopted, and the upper limit of the gas charging flow is 500sccm. Experimental results: it takes 52 seconds for the pressure to rise from 10Pa to 100Pa, the overshoot is 6Pa (overshoot rate 6%), and the stabilization time (entering the ±5Pa range) is 18 seconds. The experiment was repeated 5 times, with a rise time of 48 to 56 seconds, an overshoot of 4 to 8Pa, and a stabilization time of 15 to 22 seconds, showing good consistency. For comparison, when fixed flow gas charging (constant 500sccm) is adopted, the overshoot reaches 25Pa, and the stabilization time exceeds 60 seconds. The above experiments prove the effectiveness of the piecewise linear control strategy in vacuum pressure pre-adjustment.

[0078] The system combines inflation with flow diversion to pre-increase the pressure in the chamber to be opened until the pressure difference between the chamber and the transmission chamber is less than the door opening threshold. Only when the pressure difference is less than the door opening threshold will the control system open the sealing door to perform wafer transfer, preventing excessive pressure difference from damaging the sealing door or causing particle splashing.

[0079] This embodiment also provides a standardized removal strategy based on particle size classification. While the particle detection sensor detects the concentration, it acquires particle size distribution information through multi-channel light scattering. The control system classifies particles into at least two levels according to their size distribution. This embodiment classifies them into three levels: large particles (>1μm), medium particles (0.3μm to 1μm), and small particles (0.1μm to 0.3μm). The classification is based on the significant differences in sedimentation characteristics and airflow carrying difficulty of particles of different sizes, requiring differentiated removal strategies. The selection of the 1μm and 0.3μm boundaries is based on experimental observations: >1μm particles settle quickly, requiring high pressure differential driving force; 0.3μm to 1μm particles have moderate sedimentation characteristics and carrying difficulty; <0.3μm particles settle slowly, are easily suspended, but exhibit significant Brownian motion, requiring consideration of diffusion effects for removal.

[0080] The removal strategy parameters for each particle size class are retrieved from the preset removal strategy rule table. The structure of the removal strategy rule table is as follows: Table 1 Clearing Strategy Rules The above parameters were determined through the following experiments: Under standard operating conditions (ΔP=100Pa, oxygen environment, temperature 25℃), self-cleaning experiments were performed on standard photoresist residue particles of three particle size grades. For each grade, combinations of 5 opening durations (5 seconds, 10 seconds, 20 seconds, 30 seconds, 60 seconds), 4 valve opening degrees (20%, 40%, 60%, 80%), and 3 opening frequencies (1 time, 2 times, 3 times) were tested, and the cleaning efficiency under each combination was recorded. The cleaning efficiency was defined as the ratio of the difference in particle concentration before and after cleaning to the concentration before cleaning. The parameter combination with the highest cleaning efficiency and shortest operation time for each grade was selected from the experimental data and entered into the rule table as the preset strategy parameters.

[0081] Typical removal efficiency experimental data for each grade under standard operating conditions are as follows: large particles (>1μm, represented by dp=2μm) 65% to 80%; medium particles (0.3μm to 1μm, represented by dp=0.5μm) 80% to 92%; small particles (0.1μm to 0.3μm, represented by dp=0.2μm) 85% to 95%. The above data are based on experimental measurements of standard photoresist residue particles (density 1400kg / m³, irregular shape, aspect ratio 1.5 to 2.0) in an oxygen environment. Each data point is the average of five repeated experiments, with a relative standard deviation of less than 10%.

[0082] The logic for calling the clearing strategy rule table is as follows: The control system determines the quantity concentration ratio of each level based on the current particle size distribution; for the dominant level with the highest ratio, the preset parameters corresponding to that level are directly read from the rule table; if two levels have similar quantity concentration ratios (difference < 10%), the arithmetic mean of the parameters for the two levels is taken as the current strategy parameter. After the operation is completed, the actual clearing efficiency is calculated. If the actual clearing efficiency is lower than 70% of the nominal efficiency of that level in the rule table, an abnormal handling process is triggered: the control system displays a warning message "Current clearing efficiency is abnormal, it is recommended to check the vacuum system status" on the human-machine interface, and automatically extends the start-up time by 50% and repeats the clearing once. The 70% threshold is set based on multiple experimental observations. When the actual efficiency is lower than 70% of the nominal efficiency, it indicates that there is a significant deviation between the current working condition and the calibrated working condition, and the parameters need to be adjusted.

[0083] When the actual process differential pressure differs from the calibrated differential pressure (100Pa) in the purge strategy rule table, adjust the opening duration according to the following formula: tactual = tcalibrated × (ΔPcalibrated / ΔPactual) Where t is the adjusted opening time, t is the preset opening time corresponding to the particle size level in the rule table, ΔP is calibrated to 100Pa, and ΔP is the current actual pressure difference.

[0084] It should be noted that the "Minimum Differential Pressure Driving Force" column in the clearing strategy rule table has been quantified into the corresponding calibration differential pressure level for each particle size class: larger particles correspond to greater than 15 Pa, medium particles to 5 Pa to 15 Pa, and small particles to less than 5 Pa. The aforementioned calibration differential pressure of 100 Pa is the standard calibration operating condition differential pressure value of this rule table. Therefore, the above-mentioned start-up duration adjustment formula is essentially an adjustment based on the ratio of the differential pressure level corresponding to the minimum differential pressure driving force to the current actual differential pressure.

[0085] The physical basis of the above formula is as follows: Under laminar flow conditions, gas flow rate is directly proportional to pressure difference. To achieve the same particle removal effect, the total amount of gas required is the same; therefore, the opening time is inversely proportional to the pressure difference. For example, when the actual pressure difference is 50 Pa (half of the calibrated pressure difference), the opening time is adjusted to twice the calibrated time; when the actual pressure difference is 200 Pa (twice the calibrated pressure difference), the opening time is adjusted to half the calibrated time. This adjustment formula has been experimentally verified to be effective within the range of 50 Pa to 200 Pa, with a relative error of less than 15%.

[0086] The design of the above rule table and calling logic is based on the following physical principles: Large particles have large mass and inertia, requiring a high pressure differential driving force to overcome gravitational settling and wall adhesion. Therefore, a large valve opening and a long opening time are needed to provide sufficient airflow driving force. Medium particles have a settling velocity and carrying difficulty between large and small particles, and appropriate parameters can achieve effective removal. Although small particles are easily suspended, their Brownian motion is significant. Excessive airflow may cause particles to diffuse to various parts of the cavity and be difficult to concentrate and discharge. Therefore, a small valve opening and a short opening time can be used to achieve efficient removal by utilizing their easy suspension characteristics in combination with appropriate airflow.

[0087] The system may also include an automatic transfer unit to transfer wafers from an external loading port to the first or second process chamber, or to transfer processed wafers from the process chamber to an external unloading port. The automatic transfer unit includes a robotic arm, wafer-carrying forks, and positioning sensors. The robotic arm's movement trajectory and speed are coordinated and controlled by the control system. Before transfer, the control system obtains the current particle concentration in the chamber to be operated based on particle sensor signals and compares it with a transfer threshold. The transfer threshold is independent of the process threshold, ranging from 50% to 80% of the process threshold, i.e., 50 to 800 particles / cubic foot, preferably 200 to 300. If the transfer threshold is exceeded, a delay command is issued to pause the transfer and simultaneously initiate a transfer clearing mode. The transfer clearing mode is triggered when the particle concentration exceeds the transfer threshold but is below the process threshold. If the process threshold is exceeded, the regular clearing mode is executed first; once the concentration drops below the process threshold, it is determined whether the transfer clearing mode is needed. The transfer clearing mode sets the valve opening time to 20 to 40 seconds and the opening degree to 50% to rapidly reduce the particle concentration. If the particle level does not drop below the transfer threshold after one cleaning, the process is repeated up to three times, with a 10-30 second interval before each repetition to allow the suspended particles to settle and be detected. If the level is still above the transfer threshold after three consecutive repetitions, an alarm is triggered and subsequent processes in the chamber are suspended, prompting manual inspection. Operators can: (1) manually perform chamber self-cleaning; (2) check if the particle sensor is functioning properly; (3) check if the air pressure balance channel is blocked or if the valve is properly open. If the level is below or equal to the transfer threshold, an execution command is issued, allowing normal transfer of the particles.

[0088] Specific example: After a batch of resist removal is completed in the first process chamber, the control system prepares to execute wafer transfer. The particle sensor measures a current concentration of 450 particles / cubic foot in the first chamber. The process threshold is 300, and the transfer threshold is 200 (67% of the process threshold, within the 50% to 80% range). Since 450 is greater than 200, the control system issues a delay command to pause transfer and initiate the wafer transfer cleaning mode: the valve is opened at 60% for 30 seconds, using the pressure difference between the first and second chambers to carry suspended particles to the second chamber for discharge. After cleaning, the concentration in the first chamber is measured again at 180, which is lower than the wafer transfer threshold of 200. The control system issues an execution command, and the robotic arm performs the transfer operation. This ensures that the chamber cleanliness meets the standards before the wafer is exposed to the transfer chamber or the external environment, avoiding the risk of cross-contamination caused by direct wafer transfer in a high particle concentration environment, reducing the probability of secondary contamination on the wafer surface, and improving the surface quality after resist removal and the yield of subsequent processes.

[0089] This embodiment utilizes a dual-chamber process where asynchronous operation naturally creates or actively establishes a pressure difference. This pressure difference drives gas exchange between the two chambers, directionally carrying suspended particles from the high-pressure side to the low-pressure side for discharge with the exhaust gas. This achieves continuous particle removal without interrupting the process or requiring additional gas sources or extraction devices. The normally closed design and selective connectivity mechanism of the pressure balance channel ensures airtight isolation during the two-chamber process execution. Particle detection sensors and dual-condition judgments allow for more precise and controllable valve opening and closing. The batch-to-batch self-cleaning program effectively removes deposits from the chamber walls through pressure differential circulation and alternating roles, maintaining the cleanliness stability of the equipment during long-term operation. Pre-adjustment of pressure and pre-detection of particle concentration before wafer transfer further ensure the safety and cleanliness of the wafer transfer process.

[0090] The above description is merely a specific embodiment of this application, but the scope of protection of this application 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 this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A dual-cavity fully automated wafer processing adhesive removal system, characterized in that, include: The first process chamber and the second process chamber are sealed and isolated from each other. Each chamber is independently equipped with a vacuum system, a plasma generation system, a temperature control system and a gas path system to support the two chambers to independently execute their respective degumming process formulas. The control system, which is communicatively connected to the first process chamber and the second process chamber, is configured as follows: The first process chamber is controlled to perform a first adhesive removal process, and the second process chamber is controlled to perform a second adhesive removal process. The first adhesive removal process and the second adhesive removal process are not synchronized. By controlling the vacuum pumping speed and / or air intake flow rate of the two chambers, a pressure difference is formed between the first process chamber and the second process chamber. The pressure difference ranges from 5 Pa to 500 Pa. Furthermore, based on the pressure difference, the first process chamber and the second process chamber are controlled to exchange gases through a preset pressure balance channel. The pressure difference is used to drive the airflow to flow directionally from the high-pressure side chamber to the low-pressure side chamber, carrying the particulate matter suspended in the high-pressure side chamber to the low-pressure side chamber and discharging it with the exhaust system of the low-pressure side chamber. When the air pressure balance channel is closed, the process spaces of the first process chamber and the second process chamber are sealed and isolated from each other. When the pressure balance channel is open, the first process chamber and the second process chamber are selectively connected through the pressure balance channel.

2. The dual-cavity fully automated wafer processing adhesive removal system according to claim 1, characterized in that, The pressure balance channel includes: A bypass pipeline connecting the first process chamber and the second process chamber, wherein both ends of the bypass pipeline are respectively connected to the process spaces of the two chambers, and a control valve is provided on the bypass pipeline; The control valve is communicatively connected to the control system, and the control system adjusts the gas flow rate of the pressure balance channel by controlling the opening degree of the control valve.

3. The dual-cavity fully automated wafer processing adhesive removal system according to claim 2, characterized in that, The control system is configured as follows: Obtain the first current pressure value of the first process chamber and the second current pressure value of the second process chamber, and calculate the pressure difference between the first current pressure value and the second current pressure value; When the pressure difference is greater than the preset pressure difference threshold, the control valve is opened, allowing gas to flow from the cavity with higher pressure to the cavity with lower pressure through the bypass pipeline. The differential pressure threshold is in the range of 5 Pa to 500 Pa.

4. The dual-cavity fully automated wafer processing adhesive removal system according to claim 3, characterized in that, Also includes: A particle detection sensor is disposed in the first process chamber and / or the second process chamber, and the particle detection sensor is communicatively connected to the control system. The control system is further configured to: determine whether the particle concentration in the first process chamber and the second process chamber exceeds a preset particle concentration threshold based on the detection signal from the particle detection sensor; if the particle concentration in either chamber exceeds the threshold, then the control valve is opened.

5. The dual-cavity fully automated wafer processing adhesive removal system according to claim 4, characterized in that, Also includes: An automatic transfer unit is used to transfer the wafer to the first process cavity or the second process cavity; The control system is further configured to: before the automatic transfer unit performs wafer input or output operations, obtain the current particle concentration value of the cavity to be operated based on the detection signal of the particle detection sensor; if the current particle concentration value exceeds a preset wafer transfer particle concentration threshold, delay the wafer input or output operation until the control system performs the opening operation of the control valve and the current particle concentration value drops below the wafer transfer particle concentration threshold; wherein, the wafer transfer particle concentration threshold is lower than the particle concentration threshold.

6. The dual-cavity fully automated wafer processing adhesive removal system according to claim 4, characterized in that, The control valve is a normally closed valve; The control system is configured to keep the control valve closed when both the first process chamber and the second process chamber are in the state of performing the degumming process, so that the first process chamber and the second process chamber are sealed and isolated from each other. When the pressure difference is greater than the pressure difference threshold and the current particle concentration in the cavity exceeds the particle concentration threshold, the control system sends an opening command to the control valve to execute the normal cleaning mode; when the pressure difference is greater than the pressure difference threshold and the current particle concentration in the cavity does not exceed the particle concentration threshold but is within 30% to 80% of the particle concentration threshold, the control system sends an opening command to the control valve according to a preset low-concentration cleaning strategy; when the pressure difference is greater than the pressure difference threshold but the current particle concentration in the cavity is less than 30% of the particle concentration threshold, the control system keeps the control valve in the closed state.

7. The dual-cavity fully automated wafer processing adhesive removal system according to claim 1, characterized in that, The control system is further configured to: When formulating the process formulas for the first and second degumming processes, a pressure difference formation stage is set in the process steps of the first and second degumming processes according to the preset particle removal cycle. During the pressure difference formation stage, the first process chamber and the second process chamber are controlled to operate to different target pressure values, so that the target pressure difference between the two chambers is within the range of 5Pa to 500Pa, so as to actively establish the pressure difference.

8. The dual-cavity fully automated wafer processing adhesive removal system according to claim 1, characterized in that, The control system is further configured to: After a batch of wafers has completed the resist removal process in the first process cavity or the second process cavity, and before the next batch of wafers is loaded, the cavity self-cleaning procedure is automatically executed. The cavity self-cleaning procedure includes: The chamber to be cleaned is controlled to enter the first pressure state, while the other chamber is controlled to enter the second pressure state, so that a first pressure difference is formed between the two chambers; Open the air pressure balance channel and use the first pressure difference to drive the airflow to carry the particulate matter deposited in the cavity to be cleaned to another cavity; Close the pressure balance channel and control the other chamber to discharge the gas carrying particulate matter through its independent exhaust system; Repeat the above steps at least once, wherein before each repetition, the other cavity is controlled to be cleaned by exhaust through its independent exhaust system; or, the roles of the cavity to be cleaned and the other cavity are switched alternately, so that the two cavities are cavities to be cleaned for each other; The self-cleaning procedure is performed only when the other cavity is not carrying a wafer and no resist removal process is being performed.

9. The dual-cavity fully automated wafer processing adhesive removal system according to claim 2, characterized in that, Also includes: The transfer cavity is connected to the first process cavity and the second process cavity respectively through an openable sealing door, and is used to transfer wafers between the first process cavity, the second process cavity and the outside. The control system is further configured to: Before performing a wafer transfer operation between any process cavity and the transfer cavity: Obtain the current particle concentration value of the cavity to be opened, and determine whether the current particle concentration value is lower than the preset transfer threshold. When the current particle concentration value is lower than the transfer threshold, the current cavity pressure value of the cavity to be opened and the current transfer cavity pressure value of the transfer cavity are obtained. When the current cavity pressure value is higher than the current transmission cavity pressure value, before opening the sealing door, when the other process cavity has not performed the de-adhesion process and is in a low-pressure state, the air pressure balance channel is opened to connect the cavity to be opened with the other process cavity, and the low-pressure environment of the other process cavity is used to pre-reduce the pressure of the cavity to be opened to a value less than the pressure difference with the transmission cavity, which is less than the preset door opening threshold. When the current chamber pressure is lower than the current transmission chamber pressure, before opening the sealing door, process gas is introduced into the chamber to be opened through the independent gas path system. At the same time, the pressure balance channel is opened to allow excess gas to be diverted and discharged through the exhaust system of another process chamber. The flow rate of the excess gas does not exceed 30% of the rated processing flow rate of the exhaust system of the other process chamber. The pressure of the chamber to be opened is pre-increased to a value less than the preset door opening threshold when the pressure difference with the transmission chamber is less than the preset door opening threshold. The sealed door is opened to perform wafer transfer only when the pressure difference between the cavity to be opened and the transfer cavity is less than the preset door opening threshold.

10. The dual-cavity fully automated wafer processing adhesive removal system according to claim 4, characterized in that, The control system is further configured to: Obtain the particle size distribution information of the particles detected by the particle detection sensor; Based on the particle size distribution information, the particulate matter is divided into at least two particle size classes; Based on the settling characteristic parameters and airflow carrying difficulty parameters of each particle size class, the preset cleaning strategy parameters for the corresponding particle size class are called from the preset cleaning strategy rule table to perform self-cleaning; wherein, when the actual process pressure difference is different from the calibrated pressure difference in the cleaning strategy rule table, the opening time is adjusted according to the proportion of the minimum pressure difference driving force. The removal strategy rule table includes the preset pressure balance channel opening duration, opening frequency and / or the opening degree of the control valve corresponding to each particle size class. The removal strategy rule table is calibrated under standard operating conditions, which are a pressure difference of 100 Pa, an oxygen environment and a temperature of 25 ° C. The settling characteristic parameters include the settling velocity of the particles in the process gas, and the airflow carrying difficulty parameters include the minimum pressure difference driving force required to suspend the particles. The minimum pressure difference driving force refers to the minimum pressure difference value at which the drag force corresponding to the average airflow velocity generated in the bypass pipeline under the pressure difference condition is sufficient to overcome the sum of the effective gravity of the particles and the adhesion force to the wall.

Images