A gas phase stability control method, system, device, apparatus, medium and product

Abstract

The application relates to the technical field of semiconductor process control, and discloses a gas-phase stability control method, system, device, equipment, medium and product, which comprises the following steps: setting a target pressure and a cavity temperature, and determining an initial value of an intermediate equilibrium pressure according to the saturated vapor pressure of condensable vapor at the cavity temperature; dynamically correcting the initial value of the intermediate equilibrium pressure according to the volume concentration change rate of the condensable vapor in the cavity, obtaining a corrected value of the intermediate equilibrium pressure, and extracting the pressure of the cavity from the current pressure to the corrected value of the intermediate equilibrium pressure at a first pumping rate; stopping pumping, allowing the cavity to be airtight and stationary until the gas-liquid phase in the cavity reaches thermodynamic equilibrium, and extracting the pressure of the cavity from the corrected value of the intermediate equilibrium pressure to the target pressure at a second pumping rate. The application eliminates the sudden evaporation driving force of liquid droplets, makes the condensable vapor partial pressure and the total pressure change at a basic equal proportion in the subsequent pressure reduction process, and maintains the constant volume concentration.

Description

Technical Field

[0001] This invention relates to the field of semiconductor process control technology, specifically to a gas phase stabilization control method, system, device, equipment, medium, and product. Background Technology

[0002] In existing formic acid reflow soldering processes, the chamber needs to be evacuated from a first pressure to a second pressure to remove waste gas or switch atmospheres. Current pressure control schemes use proportional valves and vacuum pumps, employing PID (Proportional-Integral-Derivative) to track a preset pressure curve, treating the gas inside the chamber as a homogeneous mixture and assuming that the concentrations of each component change proportionally. However, for systems containing condensable vapors like formic acid, direct continuous evacuation leads to sudden evaporation of suspended droplets during the pressure reduction process. This results in non-monotonic, uncontrollable abnormal fluctuations in formic acid concentration, and the concentration change path is strongly correlated with the evacuation rate and chamber wall temperature, causing poor process repeatability. Furthermore, the condensation of droplets after being drawn into the vacuum pipeline corrodes the valves and pump body.

[0003] Existing technologies neglect the phase change of condensable vapors and droplet entrainment behavior, thus failing to achieve stable control of gas phase concentration during depressurization. Summary of the Invention

[0004] This invention provides a gas phase stability control method, system, device, equipment, medium, and product to solve the problems in the prior art where the cavity pressure is directly and continuously pumped to the target pressure, ignoring the phase change and droplet entrainment behavior of condensable vapor during the depressurization process, resulting in abnormal fluctuations in gas phase concentration during depressurization, poor process repeatability, easy contamination of the vacuum system, and lack of adaptive ability to dynamically adjust the intermediate equilibrium pressure according to the real-time concentration status.

[0005] In a first aspect, the present invention provides a gas-phase stabilization control method for pressure regulation of a semiconductor process cavity containing condensable vapor, the method comprising: Set the target pressure and cavity temperature, and determine the initial value of the intermediate equilibrium pressure based on the saturated vapor pressure of the condensable vapor at the cavity temperature; The initial value of the intermediate equilibrium pressure is dynamically corrected based on the real-time volume concentration change rate of condensable vapor in the cavity, resulting in a corrected value. This corrected value is obtained as follows: the real-time volume concentration of condensable vapor in the cavity is acquired, and the volume concentration change rate over time is calculated. The real-time volume concentration change rate is compared with a preset concentration change rate threshold. When the real-time volume concentration change rate exceeds the preset threshold, a correction amount is determined based on the deviation between the volume concentration change rate and the preset threshold. This correction amount is then added to the initial value of the intermediate equilibrium pressure to obtain the corrected value. Wherein, when the deviation exceeds a preset range, the correction amount is obtained by multiplying the deviation by a preset correction coefficient. The pressure in the cavity is pumped from the current pressure to the correction value of the intermediate equilibrium pressure at the first pumping rate. During the pumping process, the pumping flow rate is limited according to the difference between the current pressure in the cavity and the correction value of the intermediate equilibrium pressure, so that the pumping flow rate decreases as the difference decreases. Stop pumping air, seal the cavity and let it stand still, monitor the pressure change rate and the volume concentration change rate of condensable vapor in the cavity in real time until the gas and liquid phases in the cavity reach thermodynamic equilibrium. After confirming that the gas and liquid phases in the cavity have reached thermodynamic equilibrium, the pressure in the cavity is pumped from the corrected value of the intermediate equilibrium pressure to the target pressure at the second pumping rate.

[0006] This invention provides a gas-phase stabilization control method that sets an initial intermediate equilibrium pressure based on the saturated vapor pressure of condensable vapor and dynamically corrects the intermediate equilibrium pressure by incorporating the real-time concentration change rate. This allows the intermediate equilibrium pressure to adaptively adjust according to the actual deviation of the gas and liquid phases within the chamber, solving the problems of fixed pressure setpoints failing under fluctuating operating conditions and lacking the ability to dynamically adjust the intermediate pressure based on real-time concentration status. By limiting the pumping flow rate based on the difference between the current pressure and the correction value, the pressure automatically slows down the rate of pressure drop as it approaches the intermediate equilibrium pressure, avoiding sudden droplet evaporation and concentration overshoot caused by sudden changes in total pressure. Furthermore, it monitors pressure changes in real time. The rate of change of both concentration and velocity are stabilized until both reach a stable state. An objective criterion is used to determine the thermodynamic equilibrium endpoint, ensuring consistency of equilibrium states across batches and addressing the lack of an objective mechanism for determining the thermodynamic equilibrium endpoint. Based on this, the depressurization process is divided into two stages. In the first stage, pumping is stopped after reaching a corrected intermediate equilibrium pressure, allowing the system to stand. This allows the suspended droplets generated by the pressure drop within the chamber to fully evaporate, restoring thermodynamic equilibrium between the gas and liquid phases and eliminating the driving force for sudden droplet evaporation. In the second stage of pumping, since the droplets are essentially exhausted, the partial pressure of condensable vapor decreases proportionally with the total pressure, maintaining a constant volume concentration and avoiding concentration overshoot and nonlinear changes. Simultaneously, because the concentration change path no longer depends on external factors such as the pumping rate and chamber wall temperature, consistency of concentration states across different batches is ensured, improving process repeatability and weld quality consistency. Furthermore, this method reduces the amount of condensable vapor entering the pumping system by eliminating droplet entrainment, thus reducing equipment corrosion and maintenance frequency. This method only requires adding an intermediate balancing step to the existing control logic without modifying the hardware structure. It is easy to implement on existing equipment and solves the problems of directly pumping the cavity pressure to the target pressure, ignoring the phase change and droplet entrainment behavior of condensable vapor during the depressurization process, which leads to abnormal fluctuations in gas phase concentration, poor process repeatability, and easy contamination of the vacuum system.

[0007] In one alternative implementation, determining the initial value of the intermediate equilibrium pressure based on the saturated vapor pressure of the condensable vapor at the cavity temperature includes: Obtain the current pressure of the cavity; Subtract the safety pressure drop margin from the current pressure to obtain the initial value of the intermediate equilibrium pressure, where the safety pressure drop margin is less than or equal to the safety factor multiplied by the saturated vapor pressure.

[0008] In the above technical solution, by setting the initial value of the intermediate equilibrium pressure to the current pressure minus the safe pressure drop range, and the safe pressure drop range being limited by the product of the safety factor and the saturated vapor pressure of the condensable vapor at the current cavity temperature, the upper limit of the single pressure drop range is constrained by the saturated vapor pressure of the condensable vapor at the current cavity temperature and the preset safety factor. This ensures that the partial pressure of the condensable vapor in the cavity after pressure reduction is not lower than the saturated vapor pressure, thereby fundamentally suppressing the thermodynamic driving force of sudden droplet evaporation. At the same time, this setting method allows the initial value of the intermediate equilibrium pressure to be adaptively adjusted with changes in cavity temperature, eliminating the need for extensive experimental calibration for different process temperatures, and thus exhibiting broad process adaptability and ease of engineering implementation.

[0009] In one alternative implementation, the formula for calculating the correction value of the intermediate equilibrium pressure is as follows: ; in, This is a correction value for the intermediate equilibrium pressure. This is the initial value of the intermediate equilibrium pressure. The correction amount is calculated using the following formula: ; The preset correction factor. The rate of change of volume concentration. The preset concentration change rate threshold, Volume concentration, For time.

[0010] In one optional implementation, pumping the chamber pressure from the current pressure to a correction value of the intermediate equilibrium pressure at a first pumping rate includes: The cavity is evacuated at the first evacuation rate, and the pressure in the cavity is monitored in real time. When the pressure in the chamber reaches the correction value of the intermediate equilibrium pressure, the pumping stops.

[0011] In the above technical solution, by evacuating the chamber at a first evacuation rate during the first stage of evacuation and monitoring the chamber pressure in real time, evacuation is stopped immediately when the chamber pressure reaches the correction value of the intermediate equilibrium pressure. This ensures that the evacuation endpoint is precisely controlled at the intermediate equilibrium pressure value after dynamic correction based on concentration feedback, avoiding deviation from the corrected target pressure range due to excessive or insufficient evacuation. This guarantees that the subsequent settling step begins at the accurate pressure point, providing precise pressure conditions for the gas-liquid phase to reach thermodynamic equilibrium again. At the same time, the closed-loop control method of real-time monitoring and immediate stop ensures that the corrected intermediate pressure state can be accurately reproduced under the same conditions for each pressure reduction, keeping the initial equilibrium conditions consistent between batches of processes, and further improving process consistency and repeatability.

[0012] In one optional implementation, the criterion for determining whether the gas-liquid phases within the cavity have reached thermodynamic equilibrium is: When the pressure change rate is lower than the preset pressure change rate threshold and the volume concentration change rate is lower than the preset concentration change rate threshold, and this continues for a predetermined time, it is determined that the gas and liquid phases in the cavity have reached thermodynamic equilibrium, and the settling process ends.

[0013] In the above technical solution, the determination of thermodynamic equilibrium is based on the simultaneous lowering of pressure change rate and volume concentration change rate below their respective preset thresholds for a predetermined time. A dual-variable independent verification mechanism of pressure and concentration is adopted to avoid misjudgment caused by a single variable under special operating conditions (such as pressure stabilization but concentration change due to cavity micro-leakage, or concentration stabilization but pressure drift). This improves the reliability and accuracy of equilibrium determination. The requirement of a predetermined time filters out occasional fluctuations caused by sensor noise and airflow disturbance, ensuring that the determination result is based on the true steady state of the gas and liquid phases in the cavity rather than an instantaneous pseudo-equilibrium. At the same time, the dual-variable synchronous determination method does not rely on the subjective experience of the operator, making the determination of the equilibrium endpoint between different batches of processes objective and consistent.

[0014] In one optional implementation, pumping the chamber pressure from the corrected value of the intermediate equilibrium pressure to the target pressure at a second pumping rate includes: The cavity is evacuated at the second evacuation rate, and the pressure in the cavity is monitored in real time. When the pressure in the chamber reaches the target pressure, stop pumping.

[0015] In the above technical solution, after determining that the gas-liquid phase in the cavity has reached thermodynamic equilibrium, the cavity is evacuated at a second evacuation rate while the cavity pressure is monitored in real time. When the cavity pressure reaches the target pressure, the evacuation is stopped immediately. This ensures that the second stage of evacuation is started on the basis that the gas-liquid phase has reached thermodynamic equilibrium in advance. This ensures that the partial pressure of condensable vapor decreases proportionally with the total pressure and the volume concentration remains constant during this stage. It avoids concentration overshoot and nonlinear changes caused by evacuating directly before the droplets are exhausted. At the same time, the closed-loop control method of real-time monitoring and immediate stop ensures that the final pressure is precisely controlled at the target value, ensuring that each process enters the subsequent stage at the same endpoint pressure, thus improving the process consistency between batches.

[0016] In one alternative implementation, the first pumping rate is greater than the second pumping rate.

[0017] In the above technical solution, by setting the first pumping rate to be greater than the second pumping rate, the first stage of pumping completes the pressure reduction process from the current pressure to the intermediate equilibrium pressure at a faster rate, shortening the time required to reach the intermediate equilibrium pressure and improving process efficiency. Simultaneously, the second stage employs a slower pumping rate. Since the droplets are essentially exhausted and the gas-liquid phases have reached thermodynamic equilibrium at this stage, the slow pumping ensures that the partial pressure of condensable vapor steadily tracks changes in total pressure, avoiding pressure fluctuations caused by excessively rapid pumping that could interfere with the already balanced state, thus maintaining a constant concentration. The differentiated pumping rates in the two stages balance process efficiency and concentration stability.

[0018] In one alternative implementation, the method further includes: Once the pressure in the cavity reaches the target pressure, the cavity is kept sealed and left to stand for a preset confirmation time. Within a preset confirmation time, the volume concentration of condensable vapor in the chamber is monitored. Once it is confirmed that the volume concentration has not deviated from the concentration value when the target pressure is reached, the process proceeds to the next step.

[0019] In the above technical solution, by adding a settling confirmation step after reaching the target pressure, and monitoring whether the volume concentration of condensable vapor deviates from the concentration value when the target pressure is just reached, a final state verification mechanism is added to the depressurization process to ensure that the gas phase concentration is in a stable state before entering the next process step, thus avoiding process deviations caused by concentration deviations. At the same time, this confirmation step is executed at a preset fixed time, without the need for external triggering conditions. The control logic is simple and reliable, and the dependence on the online judgment module is reduced while ensuring the confirmation function, which helps to reduce the implementation complexity and cost of the control system.

[0020] In one alternative implementation, the method further includes: When the pressure drop from the current pressure to the target pressure exceeds the safe pressure drop range, multiple intermediate equilibrium pressure points are set, with the safe pressure drop range corresponding to each intermediate equilibrium pressure point decreasing progressively. Simultaneously, the cavity heating power increases progressively during each pressure drop to compensate for the temperature drop caused by the heat absorption of condensable vapor evaporation during each pressure drop. The following steps are executed sequentially until the target pressure is reached: The pressure in the cavity is pumped from the current pressure to the intermediate equilibrium pressure point of the current stage at the pumping rate corresponding to the current stage, while the cavity is heated at the heating power corresponding to the current stage. Stop pumping air and allow the cavity to remain sealed and stand until the gas and liquid phases inside the cavity reach thermodynamic equilibrium.

[0021] In the above technical solution, by setting multiple intermediate equilibrium pressure points when the pressure drop exceeds the safe pressure drop range, and by gradually reducing the safe pressure drop range at each stage, the solution matches the physical characteristics of the reduced partial pressure of condensable vapor and the greater sensitivity of the gas-liquid phase equilibrium to changes in external pressure in the later stage of pressure reduction. This avoids the re-initiation of droplet flash evaporation in the low-pressure zone due to excessive pressure drop in a single step. At the same time, the heating power of the cavity increases gradually during each stage of pressure reduction to compensate for the temperature drop caused by the heat absorption of condensable vapor evaporation during each stage of pressure reduction. Through the step-by-step coordinated adjustment of pressure and temperature parameters, the gas-liquid phase in each stage of the multi-stage pressure reduction process can restore thermodynamic equilibrium under relatively mild conditions, gradually approaching the target pressure, thus achieving stable control of gas phase concentration in a wide range of pressure reduction scenarios.

[0022] In one optional implementation, the intermediate balance pressure points of each level in the multi-level intermediate balance pressure points are determined according to a proportional graded attenuation pressure reduction strategy: that is, the safe pressure drop of the next level is a preset ratio multiple of the safe pressure drop of the previous level.

[0023] In the above technical solution, the intermediate equilibrium pressure point of each stage is determined by adopting a proportional graded attenuation pressure reduction strategy, so that the pressure drop of each subsequent stage decreases step by step. The pressure drop is smaller as it gets closer to the target pressure. This matches the actual needs of the chamber to reduce the partial pressure of condensable vapor and the gas-liquid phase balance to be more sensitive to changes in external pressure in the later stage of pressure reduction. It avoids droplet flashing and concentration fluctuations caused by excessive pressure drop in the low-pressure area. At the same time, this strategy can determine all intermediate equilibrium pressure points by setting a preset ratio, without the need for separate experimental calibration for each stage. It has good engineering feasibility and parameter reproducibility.

[0024] In one alternative implementation, the method further includes: During the extraction process, the extracted gas is heated so that the remaining condensable vapor droplets are completely vaporized and discharged.

[0025] In the above technical solution, by heating the extracted gas during the extraction process, the residual condensable vapor droplets are completely vaporized before entering the subsequent extraction path, avoiding the condensation and accumulation of droplets in the pipeline or corrosion of the extraction equipment, and reducing the frequency of equipment maintenance due to droplet residue; at the same time, the droplets are discharged in gaseous form after vaporization, without changing the atmospheric composition and concentration state in the cavity, which is consistent with the gas phase stability control target during the depressurization process, ensuring the integrity of the entire process path from the cavity to the discharge end.

[0026] In a second aspect, the present invention provides a gas-phase stabilization control system for pressure regulation of a semiconductor process cavity containing condensable vapor, the system comprising: A cavity is used to contain the workpiece to be welded and to provide a condensable vapor atmosphere. A vacuum pump is connected to the cavity via a suction pipe. An air extraction valve is installed on the air extraction pipeline to control the opening and closing of the air extraction pipeline. A pressure sensor, installed on the cavity or in the suction line, is used to detect the pressure in the cavity in real time; The controller is electrically connected to the extraction valve, vacuum pump, and pressure sensor, and is used to execute the gas phase stabilization control method of the first aspect described above or any corresponding embodiment thereof.

[0027] Thirdly, the present invention provides a gas phase stabilization control device for pressure regulation of a semiconductor process cavity containing condensable vapor, the device comprising: The parameter setting and initial value calculation module for intermediate equilibrium pressure is used to set the target pressure and cavity temperature, and to determine the initial value of intermediate equilibrium pressure based on the saturated vapor pressure of condensable vapor at the cavity temperature. The correction module is used to dynamically correct the initial value of the intermediate equilibrium pressure based on the real-time volume concentration change rate of condensable vapor in the cavity, thereby obtaining the corrected value of the intermediate equilibrium pressure. The corrected value of the intermediate equilibrium pressure is obtained as follows: the real-time volume concentration of condensable vapor in the cavity is obtained, and the volume concentration change rate over time is calculated; the real-time volume concentration change rate is compared with a preset concentration change rate threshold; when the real-time volume concentration change rate exceeds the preset concentration change rate threshold, the correction amount is determined based on the deviation between the volume concentration change rate and the preset concentration change rate threshold, and then the correction amount is added to the initial value of the intermediate equilibrium pressure to obtain the corrected value of the intermediate equilibrium pressure; wherein, when the deviation exceeds a preset range, the correction amount is obtained by multiplying the deviation by a preset correction coefficient. The first-stage air extraction control module is used to extract the pressure of the cavity from the current pressure to the correction value of the intermediate equilibrium pressure at the first air extraction rate. During the air extraction process, the air extraction flow rate is limited according to the difference between the current pressure of the cavity and the correction value of the intermediate equilibrium pressure, so that the air extraction flow rate decreases as the difference decreases. The static equilibrium control module is used to stop the pumping, so that the cavity is sealed and static, and to monitor the pressure change rate and the volume concentration change rate of condensable vapor in the cavity in real time until the gas and liquid phases in the cavity reach thermodynamic equilibrium. The second-stage pumping control module is used to determine that the gas and liquid phases in the cavity have reached thermodynamic equilibrium, and then pump the pressure in the cavity from the correction value of the intermediate equilibrium pressure to the target pressure at the second pumping rate.

[0028] Fourthly, the present invention provides an electronic device, comprising: a memory and a processor, wherein the memory and the processor are communicatively connected to each other, the memory stores computer instructions, and the processor executes the computer instructions to perform a gas phase stabilization control method according to the first aspect or any corresponding embodiment described above.

[0029] Fifthly, the present invention provides a computer-readable storage medium storing computer instructions for causing a computer to execute a gas-phase stabilization control method according to the first aspect or any corresponding embodiment described above.

[0030] In a sixth aspect, the present invention provides a computer program product, including computer instructions for causing a computer to execute a gas phase stabilization control method as described in the first aspect or any corresponding embodiment thereof.

[0031] This invention addresses the problems in existing technologies, such as directly and continuously pumping the chamber pressure to the target pressure, ignoring the phase change and droplet entrainment behavior of condensable vapors during the depressurization process, resulting in non-monotonic and uncontrollable concentration changes, poor process repeatability, and a lack of adaptive ability to dynamically adjust the intermediate equilibrium pressure based on real-time concentration conditions. It provides a gas-phase stability control method with the following advantages: This invention determines the initial value of the intermediate equilibrium pressure based on the inherent physical property parameter of the saturated vapor pressure of condensable vapor at the current cavity temperature. This ensures that the upper limit of the single pressure drop is determined by the phase change characteristics of the condensable vapor itself rather than by empirical setting, thus ensuring that the initial value has a clear physical reference at different process temperatures.

[0032] The initial value of the intermediate equilibrium pressure is dynamically corrected based on the real-time change rate of the volume concentration of condensable vapor in the cavity. This allows the actual target value of the intermediate equilibrium pressure to be adaptively adjusted according to the actual deviation of the gas and liquid phases, avoiding the failure of the fixed set value when the initial droplet volume in the cavity changes or when the temperature fluctuates. This significantly enhances the method's adaptability to actual production fluctuations.

[0033] During the evacuation process, the evacuation flow rate is limited based on the difference between the current pressure and the correction value. This causes the chamber pressure to automatically slow down the rate of pressure drop when it approaches the intermediate equilibrium pressure correction value, thus avoiding a sudden drop in total pressure caused by a sudden change in the evacuation flow rate and fundamentally eliminating the external factors that could trigger sudden evaporation of droplets.

[0034] Using the simultaneous stabilization of both pressure change rate and concentration change rate as the criterion for determining whether the gas-liquid phase has reached thermodynamic equilibrium, a bivariate independent verification mechanism is adopted to replace traditional empirical time or single-variable criteria. This effectively avoids misjudgments caused by special operating conditions of a single variable, ensuring the consistency and objectivity of equilibrium endpoint determination across batches. During the depressurization process, the partial pressure of condensable vapor is always constrained to near the saturated vapor pressure. Suspended droplets are fully evaporated during the settling period, and the gas-liquid phase returns to thermodynamic equilibrium before entering the second stage of gas extraction. At this point, since the droplets are essentially exhausted, the partial pressure of condensable vapor decreases proportionally with the total pressure, and the volume concentration remains constant. This fundamentally avoids concentration overshoot and nonlinear changes caused by direct continuous gas extraction, significantly improving the stability of gas phase concentration and the repeatability of process results.

[0035] By eliminating droplet entrainment, the amount of condensable vapor entering the pumping system in liquid form is reduced, thus lowering equipment corrosion and maintenance frequency. Moreover, this method only requires adding an intermediate balancing step to the existing control logic without modifying the hardware structure, making it easy to implement on existing equipment. Attached Figure Description

[0036] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0037] Figure 1 This is a first structural block diagram of a gas-phase stable control system according to an embodiment of the present invention; Figure 2 This is a second structural block diagram of a gas-phase stable control system according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the first process of a gas phase stability control method according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the second process of a gas phase stabilization control method according to an embodiment of the present invention; Figure 5 This is a schematic diagram of the third process of a gas phase stabilization control method according to an embodiment of the present invention; Figure 6(a) is a separate comparison of the volume concentration of condensable vapor in a gas phase stabilization control method and a continuous pumping method according to an embodiment of the present invention. Figure 6(b) is a comparison of the volume concentration of condensable vapor and the pressure of the cavity in a gas phase stabilization control method and a continuous pumping method according to an embodiment of the present invention. Figure 7 This is a structural block diagram of a gas phase stabilization control device according to an embodiment of the present invention; Figure 8 This is a schematic diagram of the hardware structure of an electronic device according to an embodiment of the present invention. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, 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.

[0039] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0040] As an optional application scenario of this invention, such as Figure 1 The diagram shown is a structural block diagram of a gas-phase stabilization control system provided by the present invention. This system is applied to pressure regulation in a semiconductor process cavity containing condensable vapor, and includes: Cavity 101 is used to contain the workpiece to be welded and to provide a condensable vapor atmosphere; wherein, the cavity is a closed container in semiconductor process equipment (such as a reflow soldering cavity) used to contain the workpiece and provide a specific process atmosphere environment; the workpiece to be welded refers to electronic components or semiconductor devices that need to be welded together, and condensable vapor refers to vapor that can change from a gaseous state to a liquid state (i.e., condensation) under specific temperature and pressure conditions, for example, formic acid vapor is the most typical condensable vapor.

[0041] Vacuum pump 102 is connected to the cavity via a gas extraction line; the gas extraction line is the gas passage / pipe connecting the cavity and the vacuum pump, used to extract gas from the cavity. Vacuum pump 102 extracts gas from the cavity through the gas extraction line, reducing the pressure in the cavity to the target pressure.

[0042] The air extraction valve 103 is installed on the air extraction pipeline and is used to control the opening and closing of the air extraction pipeline; the air extraction valve 103 is a switch valve responsible for switching between the two states of "air extraction" and "stop air extraction".

[0043] Pressure sensor 104 is installed on the cavity or on the suction line to detect the pressure of the cavity in real time.

[0044] The controller 105 is electrically connected to the extraction valve, vacuum pump and pressure sensor, and is used to perform the following gas phase stabilization control method.

[0045] In one alternative implementation, the system further includes: Non-dispersive infrared (NDIR) sensor 106, such as Figure 2 As shown, it is installed on cavity 101 and communicates with the internal space of the cavity, and is used to directly detect the volume concentration of condensable vapor in the cavity.

[0046] Isolation valve 107, such as Figure 2As shown, the pipeline installed between the evaporation buffer and the vacuum pump is used to completely isolate the vacuum pump from the upstream pipeline (including the evaporation buffer, the suction valve, and the chamber) when the vacuum pump stops.

[0047] Evaporation buffer 108, such as Figure 2 As shown, the extraction pipeline connected in series between the extraction valve and the isolation valve is used to heat the extracted residual condensable vapor droplets to complete vaporization before they enter the vacuum pump 102, preventing droplets from entering the vacuum pump and causing corrosion and equipment damage.

[0048] The workflow of the gas-phase stabilization control system provided in this embodiment is as follows: The controller calculates the safe pressure drop based on the set target pressure and cavity temperature, the saturated vapor pressure of condensable vapor at the current cavity temperature, and a preset safety factor, thereby determining an initial value for at least one intermediate equilibrium pressure. The controller acquires the volume concentration of condensable vapor in the cavity as detected in real-time by a non-dispersive infrared sensor and calculates its rate of change. Based on this rate of change, the initial value of the intermediate equilibrium pressure is dynamically corrected to obtain a corrected value. The controller controls the opening of the evacuation valve, and a vacuum pump pumps the cavity pressure from the current pressure to the corrected value of the intermediate equilibrium pressure through the evacuation pipeline at a first evacuation rate. During the evacuation process, a pressure sensor detects the total cavity pressure in real-time and feeds it back to the controller. The controller controls the opening of the evacuation valve based on the difference between the current pressure and the corrected value, causing the evacuation flow rate to decrease as the difference decreases. The extracted gas is heated to a set temperature as it flows through the evaporation buffer, causing the extracted residual condensable vapor to be heated to a lower temperature. After the gas and liquid droplets are completely vaporized, they enter the vacuum pump through the isolation valve. After reaching the correction value of the intermediate equilibrium pressure, the controller controls the pump valve to close, and the isolation valve closes simultaneously, making the cavity sealed and stationary. During this stage, the pressure sensor and the non-dispersive infrared sensor continuously detect the cavity pressure and the volume concentration of condensable vapor and transmit them to the controller. The controller calculates the pressure change rate and concentration change rate in real time. When the pressure change rate and concentration change rate are both lower than their respective preset thresholds and remain below them for a predetermined time, it is determined that the gas and liquid phases have reached thermodynamic equilibrium. After equilibrium is determined, the controller controls the isolation valve to open, and then opens the pump valve to pump the cavity pressure from the correction value of the intermediate equilibrium pressure to the target pressure at a second pumping rate. During this process, the pressure sensor monitors the pressure value in real time and feeds it back to the controller. The pumped gas flows through the evaporation buffer, is heated and vaporized, and is discharged through the isolation valve. After reaching the target pressure, the controller controls the pump valve and the isolation valve to close, completing the depressurization process.

[0049] The principle of droplet evaporation and concentration change is as follows: Assume the initial condensable vapor in the cavity is formic acid vapor, containing a certain amount of fine suspended droplets. During rapid depressurization, the cavity pressure decreases. If the partial pressure of formic acid is not adjusted in time, it will deviate from saturation. The suspended droplets will rapidly evaporate to restore saturation. The evaporation rate of the suspended droplets in the cavity is shown in the following formula: (1); in, The evaporation rate of the suspended droplets within the cavity. For time, Let be the evaporation rate constant. This represents the total surface area of ​​the droplet. For condensable vapors (such as formic acid vapor) at the cavity temperature The saturated vapor pressure at 100°C (in Pascals). The partial pressure of condensable vapor (such as formic acid vapor) (the unit is Pascal). This is the amount of condensable vapor (such as formic acid vapor) in a suspended droplet (in moles, expressed as mol). This process results in the partial pressure of the condensable vapor (such as formic acid vapor). Increase, thereby increasing the volume concentration of condensable vapors (such as formic acid vapor). Abnormally high.

[0050] This invention provides a gas-phase stability control method, including a proportional graded decay pressure reduction strategy, which limits the safe pressure drop amplitude in a single operation. This causes the pressure drop to result in the partial pressure of condensable vapor (such as formic acid vapor). It is still close to the temperature of condensable vapors (such as formic acid vapor) in the cavity. Saturated vapor pressure The evaporation of suspended droplets has a small driving force, and equilibrium is reached after standing.

[0051] The determination of the intermediate equilibrium pressure includes two steps: initial value setting and dynamic correction. First, based on the saturated vapor pressure of the condensable vapor at the current cavity temperature and the preset safety factor, calculate the upper limit constraint of the safe pressure drop (the safe pressure drop is less than or equal to the safety factor multiplied by the saturated vapor pressure), and subtract the safe pressure drop from the current pressure of the cavity to obtain the initial value of the intermediate equilibrium pressure. Secondly, during the depressurization process, the volume concentration of condensable vapor in the cavity is acquired in real time and its rate of change is calculated. This rate of change is compared with a preset concentration change rate threshold. When the real-time volume concentration change rate exceeds the preset threshold, a correction amount is determined based on the deviation between the volume concentration change rate and the preset threshold (the deviation is multiplied by a preset correction coefficient). The correction amount is then added to the initial value of the intermediate equilibrium pressure to obtain the correction value of the intermediate equilibrium pressure.

[0052] During the second depressurization, since there are no more free droplets, the partial pressure is that of condensable vapor (such as formic acid vapor). With the total pressure of the cavity (This is the sum of the partial pressures of all gases within the cavity) decreases proportionally, resulting in the volume concentration of condensable vapors (such as formic acid vapor). Keep it constant.

[0053] In summary, the core of this invention is to set an initial intermediate equilibrium pressure based on the saturated vapor pressure of condensable vapor during continuous depressurization, and to dynamically correct the intermediate equilibrium pressure by combining it with the real-time concentration change rate, so that the intermediate equilibrium pressure can adaptively adjust according to the actual deviation of the gas and liquid phases; by limiting the pumping flow rate according to the difference between the current pressure and the correction value, the depressurization rate is automatically slowed down when the pressure approaches the correction value, avoiding sudden changes in total pressure; by monitoring the pressure change rate and concentration change rate in real time until both reach stability, the thermodynamic equilibrium endpoint is determined by a bivariate objective criterion, ensuring the consistency of the equilibrium state between batches; based on this, at least one "intermediate equilibrium pressure step" is inserted, allowing the gas and liquid phases to reach thermodynamic equilibrium after a relatively gentle pressure drop, eliminating the driving force for sudden evaporation of suspended droplets, so that the partial pressure of condensable vapor changes approximately proportionally to the total pressure of the cavity during subsequent depressurization, maintaining the volume concentration of condensable vapor. Constant.

[0054] According to an embodiment of the present invention, a gas phase stabilization control method is provided. It should be noted that, in the appendix... Figure 3 To be continued Figure 5 The steps shown in the flowchart can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases the steps shown or described may be executed in a different order than that shown here.

[0055] This embodiment provides a gas phase stabilization control method, which can be used in the controller of the aforementioned gas phase stabilization control system for pressure regulation in semiconductor process cavities containing condensable vapors. Figure 3 This is a flowchart of a gas-phase stabilization control method according to an embodiment of the present invention, such as... Figure 3 As shown, the process includes the following steps: Step S301: Set the target pressure and cavity temperature, and determine the initial value of the intermediate equilibrium pressure based on the saturated vapor pressure of the condensable vapor at the cavity temperature.

[0056] Based on the process requirements (i.e., the specific reflow soldering process's target pressure and cavity temperature requirements for the cavity), set the target pressure and cavity temperature. The target pressure... This is the final chamber pressure value that the depressurization process needs to reach. Chamber temperature. It is the process temperature value that needs to be maintained inside the cavity during the reflow soldering process.

[0057] As described above, condensable vapors are vapors that can change from a gaseous state to a liquid state (i.e., condensation) under specific temperature and pressure conditions. For example, formic acid vapor is the most typical condensable vapor.

[0058] Saturated vapor pressure of condensable vapor at cavity temperature It refers to the maximum partial pressure produced by a condensable vapor when it is in dynamic equilibrium with its liquid phase at a certain temperature.

[0059] Initial value of intermediate equilibrium pressure It is an intermediate target pressure reference value obtained by static calculation based on the saturated vapor pressure of condensable vapor at the current cavity temperature and a preset safety factor.

[0060] Step S302: Based on the real-time acquired rate of change of condensable vapor volume concentration in the cavity, the initial value of the intermediate equilibrium pressure is dynamically corrected to obtain the corrected value of the intermediate equilibrium pressure. The corrected value of the intermediate equilibrium pressure is obtained as follows: the real-time volume concentration of condensable vapor in the cavity is acquired, and the rate of change of real-time volume concentration over time is calculated; the real-time volume concentration change rate is compared with a preset concentration change rate threshold; when the real-time volume concentration change rate exceeds the preset concentration change rate threshold, the correction amount is determined based on the deviation between the volume concentration change rate and the preset concentration change rate threshold, and then the correction amount is added to the initial value of the intermediate equilibrium pressure to obtain the corrected value of the intermediate equilibrium pressure; wherein, when the deviation exceeds a preset range, the correction amount is obtained by multiplying the deviation by a preset correction coefficient.

[0061] Specifically, the correction value of the intermediate equilibrium pressure is the final intermediate target pressure value obtained by dynamically correcting the initial value of the intermediate equilibrium pressure based on the real-time acquisition of the rate of change of the volume concentration of condensable vapor in the cavity.

[0062] During the depressurization process, a non-dispersive infrared sensor installed on the cavity detects the volume concentration of condensable vapor in the cavity in real time and transmits it to the controller. The controller calculates the rate of change of the concentration over time based on the real-time concentration data and compares the rate of change with a preset concentration change rate threshold. When the real-time volume concentration change rate exceeds the preset threshold, the controller determines a correction amount (the deviation is multiplied by a preset correction coefficient) based on the deviation between the volume concentration change rate and the preset threshold. The correction amount is then added to the initial value of the intermediate equilibrium pressure to obtain the corrected value of the intermediate equilibrium pressure. When the real-time volume concentration change rate does not exceed the preset threshold, the controller directly uses the initial value of the intermediate equilibrium pressure as the corrected value of the intermediate equilibrium pressure. This achieves adaptive adjustment of the target value of the intermediate equilibrium pressure according to the actual deviation of the gas and liquid phases in the cavity.

[0063] Step S303: The pressure in the cavity is pumped from the current pressure to the correction value of the intermediate equilibrium pressure at the first pumping rate. During the pumping process, the pumping flow rate is limited according to the difference between the current pressure in the cavity and the correction value of the intermediate equilibrium pressure, so that the pumping flow rate decreases as the difference decreases.

[0064] Among them, the first pumping speed It is the speed at which the vacuum pump pumps air into the cavity during the first stage of the pumping process, and the unit is mbar / s (millibar per second, 1 mbar = 100 Pa).

[0065] Pumping throughput refers to the amount of gas extracted from the cavity through the pumping line per unit time. Pumping throughput directly determines the rate of pressure drop in the cavity. The greater the throughput, the more gas is extracted per unit time, and the faster the pressure drops; the smaller the throughput, the more gradual the pressure drop.

[0066] Specifically, after the controller calculates the intermediate equilibrium pressure correction value based on the concentration change rate, the controller opens the suction valve and starts suction at the first suction rate. At the same time, the pressure sensor acquires the current pressure of the cavity in real time and calculates the difference between it and the intermediate equilibrium pressure correction value. The controller dynamically adjusts the opening of the suction valve according to this difference to limit the suction flow. When the difference is large, a large suction flow is maintained to make the pressure drop rapidly. As the pressure approaches the correction value and the difference gradually decreases, the controller gradually closes the suction valve to reduce the suction flow synchronously until the cavity pressure reaches the intermediate equilibrium pressure correction value. At this point, the controller completely closes the suction valve, and the suction flow drops to zero, completing the first stage of suction. During this process, the suction flow changes continuously as the difference decreases, so that the cavity pressure smoothly approaches the correction value, avoiding sudden drop in total pressure caused by sudden changes in suction flow that could lead to sudden evaporation of droplets.

[0067] Step S304: Stop pumping air, seal the cavity and let it stand still, monitor the pressure change rate and the volume concentration change rate of condensable vapor in the cavity in real time until the gas and liquid phases in the cavity reach thermodynamic equilibrium.

[0068] The process of sealing and settling the cavity refers to closing the evacuation valve (and isolation valve) after the evacuation reaches the intermediate equilibrium pressure, so that the evacuation pipeline between the cavity and the vacuum pump is completely cut off, and the cavity is formed into a closed state with no gas exchange with the outside world, and this state is maintained for a period of time.

[0069] Thermodynamic equilibrium refers to gas-liquid phase equilibrium, that is, between the condensable vapor phase and the suspended droplet liquid phase in the cavity, the evaporation rate and condensation rate are equal on a macroscopic scale, and the various state parameters (temperature, pressure, concentration) no longer change with time, that is, the net mass exchange is zero.

[0070] Specifically, after the cavity pressure reaches the correction value of the intermediate equilibrium pressure, the controller closes the evacuation valve (the isolation valve closes simultaneously), completely cutting off the evacuation pipeline between the cavity and the vacuum pump, and the cavity enters a sealed and static state. During this stage, the pressure sensor continuously detects the cavity pressure and transmits it to the controller to calculate the pressure change rate. The non-dispersive infrared sensor installed on the cavity simultaneously continuously detects the volume concentration of condensable vapor and transmits it to the controller to calculate the concentration change rate. The controller compares the pressure change rate and the concentration change rate with their respective preset thresholds. When both the pressure change rate and the concentration change rate are lower than their respective preset thresholds and remain below them for a predetermined time, the controller determines that the gas-liquid phase in the cavity has reached thermodynamic equilibrium and ends the static state. If either of the two change rates does not meet the stability requirements, the static state continues to wait. By simultaneously judging the pressure and concentration variables, the judgment result is ensured to be based on the true steady state of the gas-liquid phase in the cavity.

[0071] Step S305: After confirming that the gas and liquid phases in the cavity have reached thermodynamic equilibrium, the pressure in the cavity is pumped from the correction value of the intermediate equilibrium pressure to the target pressure at the second pumping rate.

[0072] Among them, the second pumping rate It is the speed at which the vacuum pump pumps air into the cavity during the second stage of the evacuation process, and the unit is mbar / s (millibar per second).

[0073] Specifically, after determining that the gas and liquid phases within the chamber have reached thermodynamic equilibrium, the controller opens the extraction valve (and isolation valve) to extract gas from the chamber at a second extraction rate. Simultaneously, the chamber pressure is monitored in real time by a pressure sensor. When the chamber pressure drops from the correction value of the intermediate equilibrium pressure to the target pressure, the extraction valve is closed, and extraction stops. During the extraction process, the extracted gas is heated to the set temperature as it flows through the evaporation buffer, causing any remaining condensable vapor droplets to completely vaporize before being discharged through the isolation valve.

[0074] This embodiment provides a gas-phase stabilization control method. By setting an initial intermediate equilibrium pressure based on the saturated vapor pressure of condensable vapor and dynamically correcting the intermediate equilibrium pressure in conjunction with the real-time concentration change rate, the intermediate equilibrium pressure can adaptively adjust according to the actual deviation of the gas and liquid phases within the cavity. This solves the problems of fixed pressure setpoints failing under fluctuating operating conditions and lacking the ability to dynamically adjust the intermediate pressure based on real-time concentration status. By limiting the pumping flow rate based on the difference between the current pressure and the correction value, the pressure automatically slows down the rate of pressure drop as it approaches the intermediate equilibrium pressure, avoiding sudden droplet evaporation and concentration overshoot caused by sudden changes in total pressure. Furthermore, by monitoring pressure changes in real time... The condensation rate and concentration change rate are stabilized until both reach a stable state. An objective criterion is used to determine the thermodynamic equilibrium endpoint, ensuring consistency of equilibrium states across batches and addressing the lack of an objective mechanism for determining the thermodynamic equilibrium endpoint. Based on this, the depressurization process is divided into two stages. In the first stage, pumping is stopped after reaching a corrected intermediate equilibrium pressure, allowing the system to stand. This allows the suspended droplets generated by the pressure drop within the chamber to fully evaporate, restoring thermodynamic equilibrium between the gas and liquid phases and eliminating the driving force for sudden droplet evaporation. In the second stage of pumping, since the droplets are essentially exhausted, the partial pressure of condensable vapor decreases proportionally with the total pressure, maintaining a constant volume concentration and avoiding concentration overshoot and nonlinear changes. Simultaneously, because the concentration change path no longer depends on external factors such as the pumping rate and chamber wall temperature, consistency of concentration states across different batches is ensured, improving process repeatability and weld quality consistency. Furthermore, this method reduces the amount of condensable vapor entering the pumping system by eliminating droplet entrainment, thus reducing equipment corrosion and maintenance frequency. This method only requires adding an intermediate balancing step to the existing control logic without modifying the hardware structure. It is easy to implement on existing equipment and solves the problems of directly pumping the cavity pressure to the target pressure, ignoring the phase change and droplet entrainment behavior of condensable vapor during the depressurization process, which leads to abnormal fluctuations in gas phase concentration, poor process repeatability, and easy contamination of the vacuum system.

[0075] This embodiment provides a gas phase stabilization control method, which can be used in the controller of the aforementioned gas phase stabilization control system for pressure regulation in semiconductor process cavities containing condensable vapors. Figure 4 This is a flowchart of a gas-phase stabilization control method according to an embodiment of the present invention, such as... Figure 4 As shown, the process includes the following steps: Step S401: Set the target pressure and cavity temperature, and determine the initial value of the intermediate equilibrium pressure based on the saturated vapor pressure of the condensable vapor at the cavity temperature.

[0076] Specifically, step S401 includes: Step a: Obtain the current pressure of the cavity; subtract the safety pressure drop margin from the current pressure to obtain the initial value of the intermediate equilibrium pressure, wherein the safety pressure drop margin is less than or equal to the safety factor multiplied by the saturated vapor pressure.

[0077] Before the pressure reduction process begins, the pressure sensor detects the current pressure in the chamber and transmits it to the controller. The controller calculates the safe pressure drop range based on a preset safety factor and the saturated vapor pressure of condensable vapor at the current chamber temperature (the safe pressure drop range equals the safety factor multiplied by the saturated vapor pressure, serving as an upper limit constraint on the single pressure reduction range). The controller then subtracts this safe pressure drop range from the current pressure to obtain the initial value of the intermediate equilibrium pressure. If the actual safe pressure drop range used is less than this upper limit, the initial value of the intermediate equilibrium pressure is increased accordingly. The specific value can be adjusted according to process requirements under this constraint.

[0078] Set the target pressure according to process requirements. cavity temperature Based on the temperature of condensable vapor in the cavity Saturated vapor pressure Calculate the safe voltage drop range Determine the initial value of the intermediate equilibrium pressure. The initial value of the intermediate equilibrium pressure. Typical values ​​range from 1100 mbar to 1500 mbar, with an initial value for the intermediate equilibrium pressure. .

[0079] Safety pressure drop The calculation formula is as follows: (2); in, This represents the current pressure within the cavity, measured by a pressure sensor; specifically, it is the initial pressure value of the cavity before the depressurization process begins. This is the initial value of the intermediate equilibrium pressure.

[0080] As can be seen from the aforementioned records, the current pressure Measured by a pressure sensor, specifically the initial pressure value of the chamber before pressure reduction begins. Safe pressure drop range. The calculation formula is shown in formula (2). The safe pressure drop amplitude determines the specific location of the initial value of the intermediate equilibrium pressure. The larger the safe pressure drop amplitude, the lower the intermediate equilibrium pressure; the smaller the safe pressure drop amplitude, the closer the initial value of the intermediate equilibrium pressure is to the current pressure, and the smoother the pressure reduction process is, but the more steps are involved. In this embodiment, the upper limit constraint of the safe pressure drop amplitude is set as shown in the following formula: (3); in, The preset safety factor is used to convert the saturated vapor pressure into the actual maximum allowable safe pressure drop. It can be obtained through calibration experiments, and the specific calibration experiment scheme is as follows: First, experimental preparation is carried out, including: injecting a determined amount of liquid formic acid into the formic acid reflow soldering chamber, heating the chamber to the process stability temperature (e.g., 50°C), and allowing the gas and liquid phases to reach thermodynamic equilibrium. At this point, the chamber pressure is... The partial pressure of formic acid reaches the saturated vapor pressure at that temperature. .

[0081] Next, an experiment was conducted to explore the ultimate pressure drop, including setting a relatively high initial pressure drop rate, such as directly transferring pressure from the cavity pressure. (e.g., 1500 mbar) Pumped to the test pressure (e.g., based on 60% of the current pressure) (i.e., 900 mbar). Real-time monitoring of the volume concentration of condensable vapor measured by a non-dispersive infrared sensor during the depressurization process. Data. If the volume concentration of condensable vapor undergoes a conflict transition (i.e., the concentration spikes nonlinearly due to the sudden evaporation of suspended droplets caused by continuous pumping), then the single-stage safety pressure drop is deemed excessive.

[0082] Then reduce the pressure drop and back-calculate the safety factor, including: gradually decreasing the single safe pressure drop amplitude (e.g., reducing by 50 mbar each time), and repeat the experiment. Observe and find the maximum safe pressure drop amplitude where the sudden evaporation of the droplet disappears and the concentration stabilizes and decreases proportionally with the current pressure. .

[0083] The safety factor under the current process can be calculated using the following formula. .

[0084] (4); because It is known (e.g., the saturated vapor pressure of condensable vapor at 50°C). For example, if the measured safe pressure drop is approximately 50 mbar, then... .

[0085] The initial value of the intermediate equilibrium pressure was finally determined. This includes: in actual processes, to ensure calculation accuracy, a certain margin is reserved, and... The value is between 0.2 and 0.5 (which can be calibrated according to actual working conditions). The initial value of the intermediate balance pressure is finally determined by the following formula: (5).

[0086] Specifically, obtain the current pressure of the cavity. The current pressure Subtract safety pressure drop The initial value of the intermediate equilibrium pressure is obtained. Among them, the safe pressure drop range Less than or equal to the preset safety factor multiplied by the saturated vapor pressure of the condensable vapor at the current cavity temperature That is, the initial value of the intermediate equilibrium pressure shall not be lower than the current pressure minus the product of the preset safety factor and the saturated vapor pressure. The specific value can be adjusted according to the process requirements under the constraint of equation (3). This is the upper limit of the safe pressure drop range.

[0087] Step S402: Based on the real-time acquired rate of change of condensable vapor volume concentration in the cavity, the initial value of the intermediate equilibrium pressure is dynamically corrected to obtain the corrected value of the intermediate equilibrium pressure. The corrected value of the intermediate equilibrium pressure is obtained as follows: the real-time volume concentration of condensable vapor in the cavity is acquired, and the rate of change of real-time volume concentration over time is calculated; the real-time volume concentration change rate is compared with a preset concentration change rate threshold; when the real-time volume concentration change rate exceeds the preset concentration change rate threshold, the correction amount is determined based on the deviation between the volume concentration change rate and the preset concentration change rate threshold, and then the correction amount is added to the initial value of the intermediate equilibrium pressure to obtain the corrected value of the intermediate equilibrium pressure; wherein, when the deviation exceeds a preset range, the correction amount is obtained by multiplying the deviation by a preset correction coefficient.

[0088] In one alternative implementation, the formula for calculating the correction value of the intermediate equilibrium pressure is as follows: (6); in, This is a correction value for the intermediate equilibrium pressure. This is the initial value of the intermediate equilibrium pressure. The correction amount is calculated using the following formula: (7); The preset correction factor. The rate of change of volume concentration. The preset concentration change rate threshold, Volume concentration, For time. Among them, the preset correction coefficient. The setting method is as follows: First, estimate the system response time constant based on the cavity volume, the saturated vapor pressure of the condensable vapor, and the system response time constant. The theoretical initial value is determined; then, under typical process conditions, calibration experiments are conducted starting from this initial value, and adjustments are made gradually. The response curve of the concentration change rate is observed until it converges smoothly near the preset threshold without significant overshoot or oscillation. This value is then determined as the optimal correction coefficient under the current process conditions. Calibration and establishment can be performed separately under different process temperatures or target pressures. A lookup function for values.

[0089] In actual processes, taking condensable vapor (such as formic acid vapor) at a cavity temperature of 50°C as an example, the non-dispersive infrared sensor detects in real time that the volume concentration of condensable vapor in the cavity is 12.5%, and the calculated volume concentration change rate is 0.008% / s. The preset concentration change rate threshold is 0.001% / s, so the deviation is 0.007% / s. Multiplying the deviation by the preset correction coefficient (such as 200 mbar·s / %), the correction amount is 1.4 mbar. If the initial value of the intermediate equilibrium pressure is 1300 mbar, then the correction value of the intermediate equilibrium pressure is 1301.4 mbar, so that the system appropriately raises the target value of the intermediate equilibrium pressure when the concentration changes too quickly, and completes the gas-liquid phase equilibrium under more stable pressure conditions.

[0090] Step S403: The pressure in the cavity is pumped from the current pressure to the correction value of the intermediate equilibrium pressure at the first pumping rate. During the pumping process, the pumping flow rate is limited according to the difference between the current pressure in the cavity and the correction value of the intermediate equilibrium pressure, so that the pumping flow rate decreases as the difference decreases.

[0091] Specifically, step S403 includes: Step b: Evacuate the cavity at the first evacuation rate and monitor the pressure in the cavity in real time; stop evacuation when the pressure in the cavity reaches the correction value of the intermediate equilibrium pressure.

[0092] The controller opens the suction valve and starts the vacuum pump at the first suction rate. Change the pressure in the cavity from the current pressure Correction value for pumping to intermediate equilibrium pressure First pumping rate A faster pumping speed can be selected (in existing vacuum reflow soldering equipment, the initial pumping rate can be flexibly adjusted according to the equipment configuration, for example, by adding a soft-pump valve and adjusting the vacuum pump speed with a frequency converter. The specific value needs to be determined comprehensively based on the chamber volume, vacuum pump capacity, and process requirements), but it is necessary to ensure that the pressure sensor can accurately track the flow. The permissible volume concentration of condensable vapors at this stage is... There was a slight increase, but it did not exceed the maximum allowable limit.

[0093] Step S404: After stopping the pumping, the cavity is sealed and left to stand. The pressure change rate and the volume concentration change rate of condensable vapor in the cavity are monitored in real time until the gas and liquid phases in the cavity reach thermodynamic equilibrium.

[0094] In one optional implementation, the criterion for determining whether the gas-liquid phases within the cavity have reached thermodynamic equilibrium is: When the pressure change rate is lower than the preset pressure change rate threshold and the volume concentration change rate is lower than the preset concentration change rate threshold, and this continues for a predetermined time, it is determined that the gas and liquid phases in the cavity have reached thermodynamic equilibrium, and the settling process ends.

[0095] Specifically, the preset pressure change rate threshold is determined based on the maximum allowable amplitude of natural pressure fluctuation in the cavity under sealed and static conditions. The specific method is as follows: Within the actual process temperature and target pressure range, the evacuation valve is closed to keep the cavity completely sealed. Pressure signals from the cavity are continuously collected using a pressure sensor for a duration no less than 2-3 times the duration required for balance determination. The collected pressure signals are statistically analyzed to calculate their root mean square noise level or peak-to-peak fluctuation amplitude. The pressure change rate threshold is then set to be greater than the upper limit of this noise fluctuation (which can be 1.5-2 times the peak-to-peak value of the noise fluctuation). Simultaneously, it must be ensured that this threshold is lower than the characteristic value of the pressure change rate corresponding to the change in the partial pressure of condensable vapor, enabling the system to effectively distinguish between the noise of the pressure sensor itself and the actual state changes of the gas and liquid phases within the cavity. For typical semiconductor process cavities, the pressure change rate threshold can be set to 0.1 mbar / s to 1 mbar / s, and fine-tuned during equipment commissioning based on the hardware characteristics of different cavities and the sensor noise level to ensure that balance determination is neither falsely triggered by sensor noise nor results in indefinite waiting due to an overly strict threshold.

[0096] The correction value when the cavity pressure reaches the intermediate equilibrium pressure. Afterwards, the controller closes the suction valve to seal the chamber and allow it to settle; then the settling time is started. Standing time The preset time is 30 to 180 seconds. During this phase, the pressure sensor detects the chamber pressure in real time and transmits it to the controller to calculate the pressure change rate, while the non-dispersive infrared sensor detects the volume concentration of condensable vapor in real time and transmits it to the controller to calculate the concentration change rate. The controller simultaneously compares the pressure change rate with a preset pressure change rate threshold (ranging from 0.001 mbar / s to 1 mbar / s) and the concentration change rate with a preset concentration change rate threshold (e.g., 0.001% / s). When both are below their respective thresholds and remain below them for a predetermined time (e.g., more than 10 seconds), it is determined that the gas-liquid phase in the chamber has reached thermodynamic equilibrium, and the settling process ends. If either of the two change rates fails to reach the stability requirement within the predetermined time, the settling process continues until both conditions are met simultaneously. Through independent verification of pressure and concentration variables, the equilibrium determination is ensured to be based on the true steady state of the gas-liquid phase in the chamber, rather than a misjudgment caused by a single variable due to special operating conditions.

[0097] Step S405: After confirming that the gas and liquid phases in the cavity have reached thermodynamic equilibrium, the pressure in the cavity is pumped from the correction value of the intermediate equilibrium pressure to the target pressure at the second pumping rate.

[0098] Specifically, step S405 includes: Step c: Pump air from the chamber at the second pumping rate and monitor the pressure in the chamber in real time; stop pumping when the pressure in the chamber reaches the target pressure.

[0099] After the gas and liquid phases inside the cavity reach thermodynamic equilibrium, the evacuation valve is opened again at the second evacuation rate. The pressure in the cavity is adjusted from the intermediate equilibrium pressure value. Draw to target pressure Since there are no excess suspended droplets, the volume concentration of condensable vapor at this stage is... It will remain essentially constant. To ensure smooth operation, the second pumping rate... (Specific values ​​need to be determined comprehensively based on the cavity volume, vacuum pump capacity, and process requirements) Less than the first pumping rate .

[0100] It should be noted that during the extraction process, the extracted gas is heated so that the remaining condensable vapor droplets are completely vaporized before being discharged.

[0101] An evaporation buffer is installed on the evacuation line and heated to a set temperature (e.g., 10°C to 30°C higher than the chamber temperature). During evacuation, the gas extracted from the chamber first flows through the evaporation buffer. Residual condensable vapor droplets entrained in the gas are heated to complete vaporization within the evaporation buffer, transforming into a gaseous state before entering the vacuum pump through an isolation valve and being discharged. This prevents droplets from condensing and accumulating in the evacuation line or corroding the vacuum pump, while also ensuring that droplets do not condense and flow back into the chamber. This aligns with the gas phase stability control target during the depressurization process, ensuring the integrity of the entire process path from the chamber to the discharge end, and preventing the exhaust process from adversely affecting the atmosphere state and concentration stability within the chamber.

[0102] Evaporation buffer volume Designed for effective cavity volume 10% to 20%.

[0103] Step S406: After the pressure in the cavity reaches the target pressure, the cavity is kept sealed and left to stand for a preset confirmation time. During the preset confirmation time, the volume concentration of condensable vapor in the cavity is monitored. After confirming that the volume concentration has not deviated from the concentration value when the target pressure is reached, the process proceeds to the next step.

[0104] Specifically, when the pressure in the cavity reaches the target pressure Afterwards, you can choose to let it stand for a preset confirmation time. Within a preset confirmation time, monitor the volume concentration of condensable vapor inside the chamber. After confirming that the volume concentration has not deviated from the concentration value when the target pressure is reached, proceed to the next process step (such as heating and welding).

[0105] Step S407: When the pressure drop from the current pressure to the target pressure exceeds the safe pressure drop range, multiple intermediate equilibrium pressure points are set. The safe pressure drop range corresponding to each intermediate equilibrium pressure point decreases progressively, while the heating power of the cavity increases progressively during each pressure drop to compensate for the temperature drop caused by the heat absorption of condensable vapor evaporation during each pressure drop. The following steps are executed progressively until the target pressure is reached: the cavity pressure is pumped from the current pressure to the intermediate equilibrium pressure point of the current stage at the pumping rate corresponding to the current stage, while the cavity is heated at the heating power corresponding to the current stage; pumping is stopped, and the cavity is sealed and left to stand until the gas and liquid phases in the cavity reach thermodynamic equilibrium.

[0106] In one optional implementation, the intermediate balance pressure points of each level in the multi-level intermediate balance pressure points are determined according to a proportional graded attenuation pressure reduction strategy: that is, the safe pressure drop of the next level is a preset ratio multiple of the safe pressure drop of the previous level.

[0107] Specifically, for large-scale pressure reduction (such as from atmospheric pressure to rough vacuum), multiple intermediate equilibrium pressure points can be set to gradually reduce pressure and achieve equilibrium, thereby enabling precise control of the volume concentration of condensable vapor.

[0108] The preset ratio is less than 1.

[0109] More specifically, the graded attenuation voltage reduction strategy is as follows: First, the controller sets the initial value of the multi-stage intermediate equilibrium pressure point. , .

[0110] Next, the controller obtains the initial value of the pressure at the intermediate equilibrium point of the current stage. With target pressure Pressure difference between: (8).

[0111] Then, the controller sets the remaining voltage drop stages. The initial pressure drop at the intermediate equilibrium pressure point of the current stage is determined using the principle of proportional attenuation. : (9); in, The attenuation ratio is set to 0.6 to 0.9. The numerator is the total residual pressure drop in this calculation, and the denominator is the sum of a geometric series. This calculation shows that the magnitude of each pressure drop decreases more significantly in later calculations, thus achieving the smoothest gas-phase transition under vacuum conditions.

[0112] Finally, the controller dynamically corrects the initial value of the intermediate equilibrium pressure of the current stage based on the real-time acquired rate of change of condensable vapor volume concentration in the cavity, obtaining the corrected value of the intermediate equilibrium pressure of the current stage (the correction amount is determined by the deviation between the rate of change of volume concentration and a preset threshold; if the deviation exceeds the preset range, it is multiplied by a preset correction coefficient). The cavity pressure is then pumped from the current pressure to this corrected value at the pumping rate corresponding to the current stage, while simultaneously heating the cavity with the heating power corresponding to the current stage to compensate for the temperature drop caused by evaporation endothermic heat. During the pumping process, the controller limits the pumping flow rate based on the difference between the current pressure and the corrected value, causing the pumping flow rate to decrease as the difference decreases. After reaching the corrected value, the controller closes the pumping valve, sealing the cavity and allowing it to settle. Pressure sensors and non-dispersive infrared sensors detect the cavity pressure and the volume concentration of condensable vapor in real time and transmit the data to the controller. The controller calculates the rate of change of pressure and the rate of change of concentration. When both are below their respective preset thresholds and remain below them for a predetermined time, the gas-liquid phase is determined to have reached thermodynamic equilibrium. After equilibrium is achieved, the controller updates the remaining stages using the following formula and continues to reduce the pressure at the intermediate equilibrium pressure point of the next stage until the final target pressure is reached: (10).

[0113] For example, taking the pressure drop from 1000 mbar atmospheric pressure to 100 mbar rough vacuum as an example, the attenuation ratio is set. Residual series The initial value of the intermediate equilibrium pressure at the current stage The target pressure is 1000 mbar. If the value is 100 mbar, then the total residual pressure drop is... The initial pressure drop of the current stage is 900 mbar. The denominator of the calculation formula (9) is 1 + 0.7 + 0.49 + 0.343 = 2.533. This equals 900 divided by 2.533, approximately 355 mbar. Therefore, the initial equilibrium pressure of the first stage is 1000 minus 355, which equals 645 mbar. After dynamic correction based on the concentration change rate, a corrected value is obtained. Gas is pumped at the current stage's pumping rate until the corrected value is reached, while simultaneously compensating for the temperature drop with corresponding heating power. During pumping, the pumping flux is limited based on the pressure difference between the corrected value and the pressure. Once reached, the system is allowed to stand until gas-liquid equilibrium is achieved; then the remaining stages are updated. Then it enters the second stage, and the remaining pressure drop is 645 minus 100, which equals 545 mbar. The denominator of the calculation formula (9) is 1 + 0.7 + 0.49 = 2.19, which is the initial pressure drop of the second stage. The pressure drop is 545 divided by 2.19, which is approximately 249 mbar. Therefore, the intermediate equilibrium pressure for the second stage is 645 minus 249, equal to 396 mbar. The pressure drop for the third stage is approximately 174 mbar, and the intermediate equilibrium pressure is 396 minus 174, equal to 222 mbar. The pressure drop for the fourth stage is approximately 122 mbar, reaching the target pressure of 100 mbar. The pressure drops at each stage decrease progressively, to 355 mbar, 249 mbar, 174 mbar, and 122 mbar respectively. Dynamic correction is performed at each stage, and pressure control and temperature control work together and are coordinated during the pressure reduction process.

[0114] This embodiment provides a gas-phase stability control method that identifies the sudden evaporation of condensable vapor droplets during depressurization as the main cause of concentration anomalies. It proposes a strategy combining a proportional graded attenuation depressurization strategy with static equilibrium, utilizing thermodynamic natural equilibrium to eliminate disturbances and fundamentally avoid concentration overshoot and nonlinear changes. Simultaneously, it introduces dynamic equilibrium judgment based on the concentration change rate, allowing the static time to adaptively end according to the actual equilibrium state, avoiding problems of excessively long or insufficient fixed times. This improves process efficiency while ensuring sufficient equilibrium, achieving stable control of gas-phase concentration and reliable reproduction of process results.

[0115] As a specific application embodiment of the present invention, combined with Figures 5 to 7 The present invention provides a gas-phase stability control method, as follows: Figure 5 As shown, the specific process is as follows: Step S501: Begin reducing the voltage; Step S502, set the target pressure And at least one initial value of intermediate equilibrium pressure. ; Step S503: Based on the real-time acquired rate of change of condensable vapor volume concentration in the cavity, the initial value of the intermediate equilibrium pressure is dynamically corrected to obtain the corrected value of the intermediate equilibrium pressure. The corrected value of the intermediate equilibrium pressure is obtained as follows: the real-time volume concentration of condensable vapor in the cavity is acquired, and the rate of change of the real-time volume concentration over time is calculated; the real-time volume concentration change rate is compared with a preset concentration change rate threshold; when the real-time volume concentration change rate exceeds the preset concentration change rate threshold, the correction amount is determined based on the deviation between the volume concentration change rate and the preset concentration change rate threshold, and then the correction amount is added to the initial value of the intermediate equilibrium pressure to obtain the corrected value of the intermediate equilibrium pressure; wherein, when the deviation exceeds a preset range, the correction amount is obtained by multiplying the deviation by a preset correction coefficient. Step S504: Perform the first stage of evacuation, reducing the chamber pressure from the current pressure. Correction value for pumping to intermediate equilibrium pressure During the evacuation process, the evacuation flow rate is limited based on the difference between the current pressure in the cavity and the correction value of the intermediate equilibrium pressure, so that the evacuation flow rate decreases as the difference decreases. Step S505: Stop pumping air, seal the cavity and let it stand still, monitor the pressure change rate and the volume concentration change rate of condensable vapor in the cavity in real time, and wait for the gas and liquid phases in the cavity to reach thermodynamic equilibrium. Step S506: Determine whether the gas and liquid phases in the cavity have reached thermodynamic equilibrium: if equilibrium has not been reached, continue to stand and wait; if equilibrium has been reached, proceed to the next step. Step S507: Perform the second stage of evacuation to reduce the pressure in the chamber from the intermediate equilibrium pressure correction value. Draw to target pressure ; Step S508, the pressure in the cavity reaches the target pressure. Then, proceed to the next process steps; Step S509, the pressure reduction process ends.

[0116] An application example of the gas-phase stabilization control method provided by this invention is as follows: The initial pressure is set at 1500 mbar (current pressure), with a target pressure of 1100 mbar. The chamber temperature is 50°C (formic acid saturated vapor pressure is approximately 166 mbar), and initially, a small amount of suspended droplets are present. In other words, under initial conditions, the gas phase within the chamber is already saturated (partial pressure of condensable vapors (such as formic acid vapor) is... The gas and liquid phases are in thermodynamic equilibrium. However, the gas phase usually contains micron-sized suspended formic acid droplets with a mass fraction of about 0.1% to 0.5%. When these droplets are depressurized rapidly in a conventional manner, the total pressure of the cavity drops sharply, causing the partial pressure of the gas phase to decrease drastically. This disrupts the existing gas-liquid equilibrium, and the droplets will immediately and violently flash evaporate (sudden evaporation), resulting in a nonlinear surge in the partial pressure of formic acid in the gas phase, ultimately leading to an abnormally high concentration.

[0117] In the gas-phase stabilization control method provided by this invention, the controller first calculates the safe pressure drop amplitude based on the saturated vapor pressure and safety factor, subtracts the safe pressure drop amplitude (approximately 200 mbar in this example) from the current pressure of 1500 mbar to obtain an initial value of approximately 1300 mbar for the intermediate equilibrium pressure; then, the initial value is dynamically corrected based on the concentration change rate detected in real time by the non-dispersive infrared sensor (when the concentration change rate exceeds a preset threshold, the deviation is multiplied by a correction coefficient to obtain the correction amount, which is then added to the initial value), to obtain the corrected value of the intermediate equilibrium pressure; and pumping begins at the first pumping rate. During the evacuation process, the controller limits the evacuation flow rate based on the difference between the current pressure and the correction value, so that the evacuation flow rate decreases as the difference decreases, achieving a smooth pressure approach to the correction value and avoiding sudden changes in total pressure. After reaching the correction value, the evacuation valve is closed to seal the cavity and allow it to stand still. The pressure sensor and the non-dispersive infrared sensor detect the cavity pressure and the volume concentration of condensable vapor in real time, respectively. The controller calculates the pressure change rate and the concentration change rate. When both are lower than their respective preset thresholds and remain below them for a predetermined time, it is determined that the gas-liquid phase has reached thermodynamic equilibrium. After equilibrium is achieved, the cavity pressure is evacuated to the target pressure at the second evacuation rate.

[0118] As shown in Figures 6(a) and 6(b), compare the following two methods: Continuous extraction method: The volume concentration of condensable vapor smoothly increases from 11.1% to 15.1%.

[0119] The present invention provides a gas phase stabilization control method (distributed pressure reduction strategy): the final volume concentration of condensable vapor is 12.8%, which is much lower than the 15.1% of continuous pumping, and the volume concentration of condensable vapor in the second stage is completely stable, which reflects the effect of staged pressure reduction balance on suppressing volume concentration overshoot and fluctuation.

[0120] As shown in Figure 6(a), this is a separate comparison of the volume concentration of condensable vapor in a gas phase stabilization control method and a continuous pumping method, focusing on the difference in the volume concentration trajectory of condensable vapor (taking formic acid vapor as an example) under the two methods.

[0121] The volumetric concentration trajectory of condensable vapor using the continuous pumping method exhibits a "sharp rise" pattern. Initially, the concentration rapidly increases from 11.1%, reaching 12.5% ​​at 10 seconds, 13.2% at 20 seconds, 14.0% at 30 seconds, and 15.1% at the target pressure after 40 seconds, subsequently remaining at that level. Throughout the depressurization process, the concentration continues to rise without any decline, ultimately deviating from the initial value by 4.0 percentage points. This indicates that the concentration change path is completely out of control due to the continuous evaporation of droplets during depressurization, causing a sustained increase in partial pressure.

[0122] In this embodiment of the invention, the volume concentration trajectory of condensable vapor in a gas-phase stabilization control method exhibits a significantly differentiated pattern: a slight increase followed by a decrease, ultimately stabilizing. During the first stage of depressurization (first 20 seconds), the concentration increases slightly from 11.1% to 13.2%, similar to the trend in the early stage of continuous pumping, but with a significantly smaller increase. After entering the settling stage (20 to 80 seconds), the volume concentration of condensable vapor gradually decreases from 13.2% to 12.7%, and remains stable at this level during the remaining 60 seconds of settling. During the second stage of pumping (80 to 100 seconds) and after reaching the target pressure, the volume concentration of condensable vapor remains constant at 12.7%, without any increase or fluctuation, indicating that the droplets have been exhausted during the settling stage. In the subsequent depressurization process, the partial pressure decreases proportionally to the total pressure, and the volume concentration of condensable vapor becomes completely stable.

[0123] As shown in Figure 6(b), this figure visually illustrates the synchronous changes in the total pressure and the volume concentration of condensable vapor in the cavity during the entire depressurization process. The solid line represents the trajectory of the volume concentration of condensable vapor changing with time and pressure using both the continuous evacuation method and the gas-phase stabilization control method provided by this invention. The dashed line represents the trajectory of the cavity pressure changing with time using both the continuous evacuation method and the gas-phase stabilization control method provided by this invention.

[0124] The variation trajectory of the volume concentration of condensable vapor with time and pressure using the continuous pumping method and the gas phase stabilization control method provided by this invention is described in detail: The volume concentration curve of the continuous pumping method rose continuously from 11.0% to 13.67%. During the entire 40-second depressurization process, the volume concentration showed a monotonically increasing trend without any signs of decline or stabilization. This indicates that the droplets continued to evaporate during the entire depressurization process, and the partial pressure of the gas phase continued to accumulate and increase. At the end of the depressurization, the volume concentration was 2.67 percentage points higher than the initial value, which reflects the characteristic of completely uncontrolled volume concentration under the continuous pumping method.

[0125] The volume concentration curve of the gas phase stabilization control method provided by this invention is as follows: During the first stage of pressure reduction (from 1500 mbar to the correction value of 1300 mbar for the intermediate equilibrium pressure), the volume concentration of condensable vapor only rises slightly to about 13.2%. During the settling stage, the suspended droplets gradually evaporate, causing the partial pressure of condensable vapor to return to saturation, and the volume concentration naturally falls back to 12.8%. During the second stage of pressure reduction (from the correction value of 1300 mbar to 1100 mbar for the intermediate equilibrium pressure), since the droplets have been basically exhausted, the partial pressure of condensable vapor decreases proportionally to the total pressure of the cavity, and the volume concentration of condensable vapor remains flat, eventually stabilizing at 12.8%. Throughout the process, the volume concentration of condensable vapor changes gradually without any sharp peaks.

[0126] The trajectory of cavity pressure change over time using the continuous pumping method and the gas phase stabilization control method provided by this invention is described in detail: The pressure of the continuous evacuation method decreases continuously from the start, linearly dropping from the initial pressure to 1100 mbar within 40 seconds and remaining stable. The pressure decreases in a uniform linear manner throughout the process, without any intermediate pauses or slowing down phases, reflecting a conventional one-step evacuation strategy.

[0127] The pressure trajectory of the gas phase stabilization control method provided by this invention exhibits a distinct step-like pattern. The pressure initially drops rapidly from the initial pressure to around 1100 mbar in the first 10 seconds, and then remains stable at 1100 mbar for the entire remaining time period (10 to 100 seconds), without any secondary pressure drop or further decrease.

[0128] This embodiment also provides a gas phase stabilization control device for implementing the above embodiments and preferred embodiments; details already described will not be repeated. As used below, the term "module" can refer to a combination of software and / or hardware that performs a predetermined function. Although the devices described in the following embodiments are preferably implemented in software, hardware implementation, or a combination of software and hardware, is also possible and contemplated.

[0129] This embodiment provides a gas phase stabilization control device for pressure regulation in a semiconductor process cavity containing condensable vapor, such as... Figure 7 As shown, it includes: The parameter setting and initial value calculation module 701 for intermediate equilibrium pressure is used to set the target pressure and the cavity temperature, and to determine the initial value of the intermediate equilibrium pressure based on the saturated vapor pressure of the condensable vapor at the cavity temperature. The correction module 702 is used to dynamically correct the initial value of the intermediate equilibrium pressure based on the real-time acquired rate of change of the volume concentration of condensable vapor in the cavity, thereby obtaining a corrected value of the intermediate equilibrium pressure. The corrected value of the intermediate equilibrium pressure is obtained by: acquiring the real-time volume concentration of condensable vapor in the cavity and calculating the rate of change of the real-time volume concentration over time; comparing the real-time volume concentration change rate with a preset concentration change rate threshold; when the real-time volume concentration change rate exceeds the preset concentration change rate threshold, determining the correction amount based on the deviation between the volume concentration change rate and the preset concentration change rate threshold, and then adding the correction amount to the initial value of the intermediate equilibrium pressure to obtain the corrected value of the intermediate equilibrium pressure; wherein, when the deviation exceeds a preset range, the correction amount is obtained by multiplying the deviation by a preset correction coefficient. The first-stage air extraction control module 703 is used to extract the pressure of the cavity from the current pressure to the correction value of the intermediate equilibrium pressure at the first air extraction rate. During the air extraction process, the air extraction flow rate is limited according to the difference between the current pressure of the cavity and the correction value of the intermediate equilibrium pressure, so that the air extraction flow rate decreases as the difference decreases. The static balance control module 704 is used to stop the pumping, so that the cavity is sealed and static, and to monitor the pressure change rate and the volume concentration change rate of condensable vapor in the cavity in real time until the gas and liquid phases in the cavity reach thermodynamic equilibrium. The second-stage pumping control module 705 is used to pump the pressure in the cavity from the correction value of the intermediate equilibrium pressure to the target pressure at the second pumping rate after the gas and liquid phases in the cavity have reached thermodynamic equilibrium.

[0130] In some optional implementations, the parameter setting and initial value calculation module 701 for intermediate equilibrium pressure includes: The initial value calculation unit for intermediate equilibrium pressure is used to obtain the current pressure of the cavity; the initial value of intermediate equilibrium pressure is obtained by subtracting the safety pressure drop amplitude from the current pressure, wherein the safety pressure drop amplitude is less than or equal to the safety factor multiplied by the saturated vapor pressure.

[0131] In one alternative implementation, the formula for calculating the correction value of the intermediate equilibrium pressure is as follows: ; in, This is a correction value for the intermediate equilibrium pressure. This is the initial value of the intermediate equilibrium pressure. The correction amount is calculated using the following formula: ; The preset correction factor. The rate of change of volume concentration. The preset concentration change rate threshold, Volume concentration, For time.

[0132] In some alternative implementations, the first-stage air extraction control module 703 includes: The first air extraction control unit is used to extract air from the cavity at a first air extraction rate and monitor the pressure of the cavity in real time; when the pressure of the cavity reaches the correction value of the intermediate equilibrium pressure, the air extraction is stopped.

[0133] In some alternative implementations, the criterion for determining whether the gas-liquid phases within the cavity have reached thermodynamic equilibrium is as follows: When the pressure change rate is lower than the preset pressure change rate threshold and the volume concentration change rate is lower than the preset concentration change rate threshold, and this continues for a predetermined time, it is determined that the gas and liquid phases in the cavity have reached thermodynamic equilibrium, and the settling process ends.

[0134] In some alternative implementations, the second-stage air extraction control module 705 includes: The second air extraction control unit is used to extract air from the cavity at the second air extraction rate and monitor the pressure of the cavity in real time; when the pressure of the cavity reaches the target pressure, the air extraction is stopped.

[0135] In some alternative implementations, the first pumping rate is greater than the second pumping rate.

[0136] In some alternative embodiments, the device further includes: The settling confirmation module is used to keep the cavity sealed and settling for a preset confirmation time after the pressure in the cavity reaches the target pressure. During the preset confirmation time, the volume concentration of condensable vapor in the cavity is monitored. After confirming that the volume concentration has not deviated from the concentration value when the target pressure is reached, the process proceeds to the next step.

[0137] In one alternative embodiment, the device further includes: The graded pressure reduction module is used when the pressure drop from the current pressure to the target pressure exceeds the safe pressure drop range. It sets multiple intermediate equilibrium pressure points, with the safe pressure drop range corresponding to each intermediate equilibrium pressure point decreasing progressively. Simultaneously, the chamber heating power increases progressively during each pressure reduction stage to compensate for the temperature drop caused by the heat absorption of condensable vapor evaporation during each stage of pressure reduction. The following steps are executed sequentially until the target pressure is reached: The pressure in the cavity is pumped from the current pressure to the intermediate equilibrium pressure point of the current stage at the pumping rate corresponding to the current stage, while the cavity is heated at the heating power corresponding to the current stage. Stop pumping air and allow the cavity to remain sealed and stand until the gas and liquid phases inside the cavity reach thermodynamic equilibrium.

[0138] In one optional implementation, the intermediate balance pressure points of each level in the multi-level intermediate balance pressure points are determined according to a proportional graded attenuation pressure reduction strategy: that is, the safe pressure drop of the next level is a preset ratio multiple of the safe pressure drop of the previous level.

[0139] In one alternative embodiment, the device further includes: The heating module is used to heat the extracted gas during the extraction process, so that the extracted residual condensable vapor droplets are completely vaporized and discharged.

[0140] The gas phase stabilization control device provided in this embodiment of the invention can execute a gas phase stabilization control method provided in any embodiment of the invention, and has the corresponding functional modules and beneficial effects for executing the method. Further functional descriptions of the various modules and units described above are the same as in the corresponding embodiments described above, and will not be repeated here.

[0141] Figure 8 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present invention.

[0142] The electronic device may include one or more processors 801, memory 802, and interfaces for connecting the components, including high-speed interfaces and low-speed interfaces. The components communicate with each other using different buses and may be mounted on a common motherboard or otherwise as required. The processor can process instructions that execute within the computer device, including instructions stored in or on memory to display graphical information of a GUI on an external input / output device (such as a display device coupled to the interface). In some alternative implementations, multiple processors and / or multiple buses may be used with multiple memories and multiple memory modules, if desired. Similarly, multiple computer devices may be connected, each providing some of the necessary operations (e.g., as a server array, a group of blade servers, or a multiprocessor system). Figure 8 Take the 801 processor as an example.

[0143] Processor 801 may be a central processing unit, a network processor, or a combination thereof. Processor 801 may further include a hardware chip. The hardware chip may be an application-specific integrated circuit (ASIC), a programmable logic device (PLD), or a combination thereof. The programmable logic device may be a complex programmable logic device (CAMP), a field-programmable gate array (FPGA), a general-purpose array logic (GDA), or any combination thereof.

[0144] The memory 802 stores instructions executable by at least one processor 801 to cause the at least one processor 801 to perform the method shown in the above embodiments.

[0145] The memory 802 may include a program storage area and a data storage area. The program storage area may store the operating system and applications required for at least one function; the data storage area may store data created based on the use of the computer device. Furthermore, the memory 802 may include high-speed random access memory and may also include non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. In some alternative embodiments, the memory 802 may optionally include memory remotely located relative to the processor 801, and these remote memories may be connected to the computer device via a network. Examples of such networks include, but are not limited to, the Internet, intranets, local area networks, mobile communication networks, and combinations thereof.

[0146] The memory 802 may include volatile memory, such as random access memory; the memory may also include non-volatile memory, such as flash memory, hard disk or solid-state drive; the memory 802 may also include a combination of the above types of memory.

[0147] The electronic device also includes a communication interface 803 for the computer device to communicate with other devices or communication networks.

[0148] Figure 8 The electronic device shown is merely an example and should not be construed as limiting the functionality and scope of use of the embodiments of the present invention.

[0149] This invention also provides a computer-readable storage medium. The methods described above according to embodiments of the invention can be implemented in hardware or firmware, or implemented as computer code that can be recorded on a storage medium, or implemented as computer code downloaded via a network and originally stored on a remote storage medium or a non-transitory machine-readable storage medium and then stored on a local storage medium. Thus, the methods described herein can be processed by software stored on a storage medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware. The storage medium can be a magnetic disk, optical disk, read-only memory, random access memory, flash memory, hard disk, or solid-state drive, etc.; further, the storage medium can also include combinations of the above types of memory. It is understood that computers, processors, microprocessor controllers, or programmable hardware include storage components capable of storing or receiving software or computer code. When the software or computer code is accessed and executed by the computer, processor, or hardware, a gas-phase stabilization control method shown in the above embodiments is implemented.

[0150] A portion of this invention can be applied as a computer program product, such as computer program instructions, which, when executed by a computer, can invoke or provide the methods and / or technical solutions according to the invention through the operation of the computer. Those skilled in the art will understand that the forms in which computer program instructions exist in a computer-readable medium include, but are not limited to, source files, executable files, installation package files, etc. Correspondingly, the ways in which computer program instructions are executed by a computer include, but are not limited to: the computer directly executing the instructions, or the computer compiling the instructions and then executing the corresponding compiled program, or the computer reading and executing the instructions, or the computer reading and installing the instructions and then executing the corresponding installed program. Here, the computer-readable medium can be any available computer-readable storage medium or communication medium accessible to a computer.

[0151] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A gas-phase stability control method, characterized in that, The method for pressure regulation of a semiconductor process cavity containing condensable vapor includes: Set the target pressure and cavity temperature, and determine the initial value of the intermediate equilibrium pressure based on the saturated vapor pressure of the condensable vapor at the cavity temperature; The initial value of the intermediate equilibrium pressure is dynamically corrected based on the real-time volume concentration change rate of the condensable vapor in the cavity to obtain a corrected value of the intermediate equilibrium pressure. The corrected value of the intermediate equilibrium pressure is obtained as follows: the real-time volume concentration of the condensable vapor in the cavity is obtained, and the volume concentration change rate over time is calculated. The real-time volume concentration change rate is compared with a preset concentration change rate threshold. When the real-time volume concentration change rate exceeds the preset concentration change rate threshold, a correction amount is determined based on the deviation between the volume concentration change rate and the preset concentration change rate threshold. This correction amount is then added to the initial value of the intermediate equilibrium pressure to obtain the corrected value of the intermediate equilibrium pressure. Wherein, when the deviation exceeds a preset range, the correction amount is obtained by multiplying the deviation by a preset correction coefficient. The pressure in the cavity is pumped from the current pressure to the correction value of the intermediate equilibrium pressure at a first pumping rate. During the pumping process, the pumping flow rate is limited according to the difference between the current pressure in the cavity and the correction value of the intermediate equilibrium pressure, so that the pumping flow rate decreases as the difference decreases. Stop pumping air, seal the cavity and let it stand still, monitor the pressure change rate and the volume concentration change rate of the condensable vapor in the cavity in real time until the gas and liquid phases in the cavity reach thermodynamic equilibrium. After determining that the gas and liquid phases in the cavity have reached thermodynamic equilibrium, the pressure in the cavity is pumped from the corrected value of the intermediate equilibrium pressure to the target pressure at a second pumping rate.

2. The method according to claim 1, characterized in that, The determination of the initial value of the intermediate equilibrium pressure based on the saturated vapor pressure of the condensable vapor at the cavity temperature includes: Obtain the current pressure of the cavity; Subtracting the safety pressure drop margin from the current pressure yields the initial value of the intermediate equilibrium pressure, wherein the safety pressure drop margin is less than or equal to the safety factor multiplied by the saturated vapor pressure.

3. The method according to claim 1, characterized in that, The formula for calculating the correction value of the intermediate equilibrium pressure is as follows: ； in, This is a correction value for the intermediate equilibrium pressure. This is the initial value of the intermediate equilibrium pressure. The correction amount is calculated using the following formula: ； The preset correction factor. The rate of change of volume concentration. The preset concentration change rate threshold, Volume concentration, For time.

4. The method according to claim 1, characterized in that, The correction value for pumping the chamber pressure from the current pressure to the intermediate equilibrium pressure at the first pumping rate includes: The cavity is evacuated at the first evacuation rate, and the pressure in the cavity is monitored in real time. When the pressure in the cavity reaches the correction value of the intermediate equilibrium pressure, the pumping stops.

5. The method according to claim 1, characterized in that, The criteria for determining whether the gas and liquid phases within the cavity have reached thermodynamic equilibrium are as follows: When the pressure change rate is lower than the preset pressure change rate threshold and the volume concentration change rate is lower than the preset concentration change rate threshold, and this continues for a predetermined time, it is determined that the gas and liquid phases in the cavity have reached thermodynamic equilibrium, and the settling period ends.

6. The method according to claim 1, characterized in that, The step of pumping the chamber pressure from the corrected value of the intermediate equilibrium pressure to the target pressure at a second pumping rate includes: The cavity is evacuated at the second evacuation rate, and the pressure of the cavity is monitored in real time. When the pressure in the cavity reaches the target pressure, the pumping stops.

7. The method according to claim 1, characterized in that, The first pumping rate is greater than the second pumping rate.

8. The method according to claim 1, characterized in that, The method further includes: Once the pressure in the cavity reaches the target pressure, the cavity is kept sealed and left to stand for a preset confirmation time. Within the preset confirmation time, the volume concentration of condensable vapor in the cavity is monitored. After confirming that the volume concentration has not deviated from the concentration value when the target pressure is reached, the process proceeds to the next step.

9. The method according to claim 2, characterized in that, The method further includes: When the pressure drop from the current pressure to the target pressure exceeds the safe pressure drop range, multiple intermediate equilibrium pressure points are set, with the safe pressure drop range corresponding to each intermediate equilibrium pressure point decreasing progressively. Simultaneously, the cavity heating power increases progressively during each pressure drop to compensate for the temperature drop caused by the heat absorption of condensable vapor evaporation during each pressure drop. The following steps are executed sequentially until the target pressure is reached: The pressure in the cavity is pumped from the current pressure to the intermediate equilibrium pressure point of the current stage at the pumping rate corresponding to the current stage, while the cavity is heated at the heating power corresponding to the current stage. Stop pumping air and allow the cavity to remain sealed and stationary until the gas and liquid phases within the cavity reach thermodynamic equilibrium.

10. The method according to claim 9, characterized in that, The intermediate balance pressure points at each level in the multi-level intermediate balance pressure points are determined according to a proportional graded attenuation and pressure reduction strategy: that is, the safe pressure drop of the next level is a preset ratio multiple of the safe pressure drop of the previous level.

11. The method according to claim 1, characterized in that, The method further includes: During the extraction process, the extracted gas is heated so that the remaining condensable vapor droplets are completely vaporized and discharged.

12. A gas-phase stable control system, characterized in that, The system is used for pressure regulation of a semiconductor process cavity containing condensable vapor, the system comprising: A cavity is used to contain the workpiece to be welded and to provide a condensable vapor atmosphere. A vacuum pump is connected to the cavity via a suction pipe; An air extraction valve is installed on the air extraction pipeline to control the opening and closing of the air extraction pipeline; A pressure sensor is installed on the cavity or the air extraction pipeline to detect the pressure of the cavity in real time. A controller, electrically connected to the suction valve, the vacuum pump, and the pressure sensor, is used to execute the gas phase stabilization control method according to any one of claims 1 to 11.

13. A gas phase stabilization control device, characterized in that, The device for pressure regulation of a semiconductor process cavity containing condensable vapor includes: The parameter setting and initial value calculation module for intermediate equilibrium pressure is used to set the target pressure and cavity temperature, and to determine the initial value of intermediate equilibrium pressure based on the saturated vapor pressure of condensable vapor at the cavity temperature. The correction module is used to dynamically correct the initial value of the intermediate equilibrium pressure based on the real-time acquired rate of change of the volume concentration of condensable vapor in the cavity, thereby obtaining a corrected value of the intermediate equilibrium pressure. The corrected value of the intermediate equilibrium pressure is obtained as follows: The real-time volume concentration of condensable vapor in the cavity is acquired, and the rate of change of the real-time volume concentration over time is calculated. The real-time volume concentration change rate is compared with a preset concentration change rate threshold. When the real-time volume concentration change rate exceeds the preset concentration change rate threshold, a correction amount is determined based on the deviation between the volume concentration change rate and the preset concentration change rate threshold. This correction amount is then added to the initial value of the intermediate equilibrium pressure to obtain the corrected value of the intermediate equilibrium pressure. Wherein, when the deviation exceeds a preset range, the correction amount is obtained by multiplying the deviation by a preset correction coefficient. The first-stage air extraction control module is used to extract the pressure of the cavity from the current pressure to the correction value of the intermediate equilibrium pressure at a first air extraction rate. During the air extraction process, the air extraction flow rate is limited according to the difference between the current pressure of the cavity and the correction value of the intermediate equilibrium pressure, so that the air extraction flow rate decreases as the difference decreases. The static equilibrium control module is used to stop the pumping, so that the cavity is sealed and static, and to monitor the pressure change rate and the volume concentration change rate of the condensable vapor in the cavity in real time until the gas and liquid phases in the cavity reach thermodynamic equilibrium. The second-stage pumping control module is used to determine that after the gas-liquid phase in the cavity reaches thermodynamic equilibrium, it pumps the pressure in the cavity from the correction value of the intermediate equilibrium pressure to the target pressure at a second pumping rate.

14. An electronic device, characterized in that, include: A memory and a processor are communicatively connected, the memory storing computer instructions, and the processor executing the computer instructions to perform the gas phase stabilization control method according to any one of claims 1 to 11.

15. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer instructions for causing a computer to perform the gas-phase stabilization control method according to any one of claims 1 to 11.

16. A computer program product, characterized in that, Includes computer instructions for causing a computer to execute the gas phase stabilization control method according to any one of claims 1 to 11.

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