A monitoring control method and system for a semiconductor process gas path

Abstract

The application discloses a kind of monitoring control method and system for semiconductor process gas path, it is related to semiconductor gas concentration detection field, including the following steps: a measuring instrument is set downstream of gas mixer and upstream of process chamber;Conducting downflow and upflow time detection to flow channel gas, and then concentration inversion is carried out to obtain the actual concentration value and total flow of mixed gas after sound velocity and flow compensation;Actual concentration value is compared with preset target concentration, and concentration deviation is obtained, and the opening of the flow control valve of at least one branch on the upstream of process gas path is adjusted according to concentration deviation;Total flow is compared with the sum of the flow set value of all branches upstream in real time, and when the deviation exceeds the preset error, safety interlock is triggered.The above scheme is used, the concentration and total flow of mixed process gas are measured without contacting process gas, and closed-loop control and redundant safety check of gas entering process chamber are realized.

Description

Technical Field

[0001] This invention relates to the field of semiconductor gas concentration detection technology, and in particular to a monitoring and control method for semiconductor process gas paths. Background Technology

[0002] As semiconductor devices evolve towards smaller feature sizes, more complex structures, and tighter process windows, dry processes such as etching and thin-film deposition become increasingly reliant on real-time process monitoring. Precise control of process gas concentration is a key determinant of advanced process technologies. Currently, semiconductor process gas paths still rely on mass flow controllers (MFCs) as the core execution unit. However, due to inherent limitations based on principles such as thermal diffusion, their measuring elements must be directly exposed to the process gas, posing a risk to contamination control. Furthermore, the limited adjustable range, high dependence of measurement accuracy on the set range, and limited single-branch measurement capabilities necessitate the construction of a multi-level MFC architecture with numerous branches and varying ranges for precise control of complex gas formulations. This not only increases system complexity and maintenance difficulty but also leads to structural defects in the gas path, such as multi-point error accumulation, response lag, and the inability to verify drift in real time.

[0003] Currently, process control systems generally rely on the assumption of correct flow rates for each branch, making it impossible to directly verify the actual total gas flow rate, component concentration, or dynamic ratio of the gas entering the process chamber after mixing. Under complex process conditions, if a branch experiences drift, blockage, leakage, or valve malfunction, the system often fails to detect the anomaly in time at the gas mixing front end, causing recipe deviation or sudden changes in the chamber atmosphere, leading to irreversible process deviations. Furthermore, traditional concentration analyzers are typically invasive, high-latency, and expensive standalone devices, lacking integration with MFC systems and failing to achieve rapid-response closed-loop control. This makes real-time verification and dynamic closed-loop control of mixed gases one of the core challenges that the industry has long struggled to solve.

[0004] Therefore, there is an urgent need to provide a monitoring and control method and system for the gas path in semiconductor processes to solve the technical problems existing in the prior art. Summary of the Invention

[0005] The purpose of this invention is to provide a monitoring and control method and system for semiconductor process gas paths, in order to solve the technical problem in the prior art of how to measure the concentration and total flow rate of mixed process gases without contacting the process gases, and thereby implement direct closed-loop control and redundant safety verification of upstream gas paths based on the final gas parameters.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows:

[0007] First aspect: A monitoring and control method for gas paths in semiconductor processes, comprising the following steps:

[0008] A measuring instrument is connected in series via an interface and positioned downstream of the gas mixer and upstream of the process chamber in the process gas path. The measuring instrument includes a flow channel, an external clamp-on ultrasonic time difference measurement module, a temperature sensing unit, and a pressure sensing unit.

[0009] The external clamp-on ultrasonic time difference measurement module is used to detect the propagation time of the mixed gas in the flow channel in both the forward and reverse directions. Combined with the temperature and pressure parameters obtained by the temperature sensing unit and the pressure sensing unit, the sound velocity and flow rate are compensated. Based on the compensated sound velocity, the concentration is inverted to simultaneously obtain the actual concentration value X and the total flow rate Q of the mixed gas.

[0010] The actual concentration value X is compared with the preset target concentration Y to obtain the concentration deviation. According to the concentration deviation Adjust the opening of the flow control valve of at least one branch upstream of the process gas path to maintain the concentration of the mixed gas entering the process chamber at the target concentration Y;

[0011] The total flow rate Q is compared in real time with the sum of the flow rate settings of all upstream branches ∑Q. When the deviation exceeds the preset error threshold, a safety interlock is triggered.

[0012] Furthermore, the compensation for sound velocity and flow rate is calculated using the following two-parameter coupled model:

[0013]

[0014]

[0015] in, The compensated speed of sound, The compensated gas flow rate, and These represent the propagation times of the ultrasonic waves in the downstream and upstream directions, respectively; L is the effective acoustic path length between the transducers. This is the temperature compensation factor; As a stress compensation factor; This is a correction factor used to eliminate flow rate deviations caused by temperature gradients.

[0016] Furthermore, the concentration inversion based on the compensated sound velocity includes establishing the following nonlinear inversion equation based on the mixed gas sound velocity model:

[0017] ;

[0018] in, The average molar mass of the binary gas mixture;

[0019] ;

[0020] in, satisfy:

[0021]

[0022] in, The molar concentration of the target component. The compensated speed of sound, The gas constant is For real-time measured temperature, and The adiabatic index of each component in the binary mixed process gas.

[0023] Furthermore, the concentration inversion process employs a numerical iterative solution method, which is at least one of Newton's iteration method, the bisection method, or the quasi-Newton method, to ensure rapid convergence to a unique physical solution within a preset concentration range.

[0024] Furthermore, based on the concentration deviation The opening degree of the flow control valve for at least one branch upstream of the process gas line includes:

[0025] The corresponding valve adjustment amount is calculated based on the concentration deviation, and the real-time opening degree of the flow control valve is updated through at least one of proportional regulation, integral regulation, or proportional-integral regulation, so that the concentration of the mixed gas after the flow of each branch is superimposed gradually approaches the target concentration.

[0026] Furthermore, a flow controller is installed on the branch line, which is electrically connected to the flow control valve;

[0027] When the deviation exceeds the preset error threshold, it is determined that at least one of the following abnormal situations exists: the flow controller of the branch is inaccurate or malfunctioning, the gas line is leaking, or the flow control valve of the branch is malfunctioning.

[0028] Furthermore, the triggering of the safety interlock includes at least one of the following operations: sending an alarm signal to the upper unit, automatically shutting off the gas supply to the main gas circuit or the abnormal branch circuit, or terminating the current process flow.

[0029] Secondly, a monitoring and control system for a semiconductor process gas path, used to execute the monitoring and control method for a semiconductor process gas path as described above, comprising:

[0030] A monitoring and control unit is connected in series downstream of the gas mixer and upstream of the process chamber in the process gas path. It is used to synchronously measure the concentration and total flow rate of the mixed gas in a non-contact manner. The monitoring and control unit includes the clamp-on ultrasonic time difference measurement module, the temperature sensing unit, and the pressure sensing unit.

[0031] The flow control unit includes the flow control valves disposed on each gas branch upstream of the gas mixer;

[0032] The system controller is communicatively connected to both the monitoring control unit and the flow control unit.

[0033] The system controller is used to receive the concentration and total flow rate from the monitoring and control unit, control the opening of the flow control valve to adjust the gas flow rate according to the deviation between the concentration and a preset target concentration, and trigger a safety interlock action according to the deviation between the total flow rate and the sum of the set values ​​of the flow rates of each branch.

[0034] Furthermore, the clamp-on ultrasonic time difference measurement module:

[0035] The clamp body clamps and covers the outside of the flow channel, and the clamp body has an installation space.

[0036] A transducer assembly includes a pair of ultrasonic transducers disposed within the mounting space.

[0037] Furthermore, the flow channel is a full-bore zero-pressure-loss flow channel, and the inner wall of the flow channel is coated with an inert passivation layer.

[0038] The beneficial effects of the monitoring and control method and system for semiconductor process gas paths provided by this invention are as follows: By deploying the measuring instruments downstream of the gas mixer and upstream of the process chamber, and utilizing an externally clamped ultrasonic time-of-flight measurement module, a temperature sensing unit, and a pressure sensing unit to collaboratively acquire the downstream and upstream propagation time, temperature, and pressure parameters of the mixed gas, the system can obtain the compensated sound velocity and actual flow rate in real time without direct contact with the process gas. Based on this sound velocity inversion model, the true concentration value X and total flow rate Q of the mixed gas can be calculated simultaneously, thereby overcoming the structural limitation of existing technologies that rely solely on the flow rate setpoints of each branch to infer the mixing state. With the real-time monitoring of X and Q, this invention can directly perform closed-loop control on the mixed gas that finally enters the process chamber, allowing the flow control valve of the upstream branch to autonomously adjust according to the concentration deviation ΔX, ensuring the long-term stability of the process gas ratio. Simultaneously, by comparing the total flow rate Q with the setpoint ∑Q of all upstream branch flow rates, abnormal states that are difficult to detect in traditional systems, such as branch blockage, leakage, valve malfunction, or MFC drift, can be identified in a timely manner, triggering safety interlocks and achieving redundant verification and protection of the gas path system. Thus, while ensuring zero pollution and zero disturbance, this invention achieves real-time verification of both mixed gas concentration and total flow rate, direct closed-loop control of process ratios, and immediate judgment of gas path anomalies, significantly improving the stability, safety, and controllability of the semiconductor dry process gas path. Attached Figure Description

[0039] Figure 1 This is a flowchart of a monitoring and control method for a semiconductor process gas path according to the present invention;

[0040] Figure 2 This is a diagram showing the installation location of the measuring instrument according to an embodiment of the present invention;

[0041] Figure 3 This is a schematic diagram of a monitoring and control system for a semiconductor process gas path according to an embodiment of the present invention;

[0042] Figure 4 This is a schematic diagram of the fixture body according to an embodiment of the present invention;

[0043] Figure 5 This is a cross-sectional view of the fixture body according to an embodiment of the present invention.

[0044] Reference numerals: 1. Measuring instrument; 11. Flow channel; 12. External clamp-on ultrasonic time difference measurement module; 13. Temperature sensing unit; 14. Pressure sensing unit; 15. Fixture body; 16. Transducer; 2. Gas mixer; 3. Thin film growth equipment; 4. Interface; 5. Flow control valve; 6. System controller; 7. Pressure controller. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. 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. Unless otherwise defined, the technical or scientific terms used herein should have the ordinary meaning understood by those skilled in the art. The terms "comprising" and similar expressions used herein mean that the element or object preceding the word covers the element or object listed after the word and its equivalents, but does not exclude other elements or objects.

[0046] Combined with appendix Figure 1 - Appendix Figure 5 The specific embodiments of the present invention will be further described in detail below.

[0047] In a first aspect, in some embodiments of the present invention, a monitoring and control method for a semiconductor process gas path is proposed. The following detailed description, in conjunction with the accompanying drawings, explains the overall steps of the method, the extraction of each module, the measurement and data flow, and the mathematical derivation and solution process for concentration inversion, so as to illustrate the feasibility of the present invention and several modified embodiments.

[0048] A monitoring and control method for gas paths in semiconductor processes includes the following steps:

[0049] A measuring instrument 1 is connected in series via interface 4 downstream of the gas mixer 2 in the process gas path and upstream of the process chamber. The measuring instrument 1 includes a flow channel 11, an external clamp-on ultrasonic time difference measurement module 12, a temperature sensing unit 13, and a pressure sensing unit 14.

[0050] The external clamp-on ultrasonic time difference measurement module 12 is used to detect the propagation time of the mixed gas in the flow channel 11 in both the forward and reverse directions. Combined with the temperature and pressure parameters obtained by the temperature sensing unit 13 and the pressure sensing unit 14, the sound velocity and flow rate are compensated. Based on the compensated sound velocity, the concentration is inverted to simultaneously obtain the actual concentration value X and the total flow rate Q of the mixed gas.

[0051] The actual concentration value X is compared with the preset target concentration Y to obtain the concentration deviation. According to the concentration deviation Adjust the opening of the flow control valve 5 of at least one branch upstream of the process gas path to maintain the concentration of the mixed gas entering the process chamber at the target concentration Y.

[0052] The total flow rate Q is compared in real time with the sum of the flow rate settings of all upstream branches ∑Q. When the deviation exceeds the preset error threshold, a safety interlock is triggered.

[0053] Reference Figure 2 In some embodiments of the present invention, the monitoring and control unit can be located at any gas path position downstream of the gas mixer 2 and upstream of the process chamber in the thin film growth equipment 3. Depending on the specific gas path structure of the process equipment, this position may include, but is not limited to, the following forms: a pipeline section before the carrier gas enters the gas mixer 2, used to monitor the flow rate and state of the carrier gas before it carries the source liquid; in some embodiments, the gas mixer 2 is a bubbler; a pipeline section after the source gas exits from the gas mixer 2, used to monitor the vapor-type source gas carried out by the gas mixer 2; a mixing pipeline section before the source gas is directly supplied to the thin film growth equipment 3; and a downstream section after the carrier gas and source gas are mixed in the gas mixer 2. In some specific embodiments, a pressure controller 7 is also provided in the downstream section after the carrier gas and source gas are mixed in the gas mixer 2.

[0054] In some specific embodiments of the present invention, the clamp-on ultrasonic time difference measurement module 12 further includes a transducer 16 for emitting ultrasonic waves, a data processing submodule, and a compensation and inversion submodule. The measurement process begins with the clamp-on ultrasonic time difference measurement module 12 emitting and receiving ultrasonic pulses between the transducers 16 on both sides of the flow channel 11 to obtain the downstream propagation time. With the time of reverse propagation (All values ​​are pre-processed time differences). Simultaneously, the temperature sensing unit and the pressure sensing unit collect temperature data in real time at adjacent locations. The raw time difference data, along with pressure P, is uploaded in synchronous frames by the data acquisition circuit to the data processing submodule for real-time preprocessing, including noise reduction, window averaging, and outlier removal. The preprocessed data is then input to the compensation and inversion submodule, where the uncompensated sound velocity and flow velocity are first calculated.

[0055]

[0056]

[0057] in, The effective acoustic path between transducers (determined by design and calibration). and The propagation times of the ultrasonic waves in the forward and reverse directions are respectively determined, followed by the temperature compensation factor obtained from calibration. Stress compensation factor And a correction factor for eliminating flow rate deviations caused by temperature gradients;

[0058] Subsequently, the compensation for sound velocity and flow rate is calculated using the following two-parameter coupling model:

[0059]

[0060]

[0061]

[0062] in, The compensated speed of sound, The gas flow rate after compensation is L, and the effective acoustic path length between transducers is L. This is the temperature compensation factor; As a stress compensation factor; This is a correction factor used to eliminate flow rate deviations caused by temperature gradients. To improve compensation robustness, this embodiment uses... and Use piecewise polynomial calibration or table lookup combined with real-time interpolation to reduce the impact of short-term noise.

[0063] In some other embodiments of the invention, based on the compensated speed of sound A nonlinear inversion equation is established for a binary gas mixture to determine the molar concentration of the target component. The nonlinear inversion equation starts from the thermodynamic expression of the gas sound velocity, that is, at a given temperature... The following conditions must be met at the speed of sound: The molar mass of the mixture is given according to a linear mixing relationship, that is, the average molar mass of the binary gas mixture: Mixed adiabatic index The specific heat mixing method is expressed as The measured With known Substituting the equations, we obtain the nonlinear inversion equation to be solved: ;in, The molar concentration of the target component. The compensated speed of sound, The gas constant is For real-time measured temperature, and The adiabatic index of each component in a binary mixed process gas. It is the molar mass of the target component; It is the molar mass of another component.

[0064] In some embodiments of the present invention, the concentration inversion process employs a numerical iterative solution method, which is at least one of Newton's iteration method, the bisection method, or the quasi-Newton method, to ensure rapid convergence to a unique physical solution within a preset concentration range.

[0065] In some specific embodiments of the present invention, for the convenience of numerical solution, the following are given: about The derivative form is convenient for use in Newton-like iterative algorithms. It can be derived from the chain rule and the quotient rule. ,in ,and The specific heat mixture method described above can be used to obtain the following: Differentiation yields an explicit expression, thus enabling the determination of... The closed-form expression. Based on this reciprocal, the concentration inversion module can employ Newton's iteration: given an initial guess... , Take the solution from the previous time step or a common concentration value from the process. Through... Iterate until... .in, This is the preset convergence threshold.

[0066] To prevent Newton's method from diverging when the initial value is poor or the derivative is close to zero, this embodiment further introduces step size limits and interval constraints into the algorithm: if the update step size exceeds the allowable range, a binary reduction is performed or the algorithm reverts to a robust binary search process; if convergence is not achieved within the maximum number of iterations, the result is marked as abnormal and a calibration or alarm process is triggered by the abnormality diagnosis module. To improve noise robustness, the input is processed during the inversion process. and Perform low-pass filtering.

[0067] In some specific embodiments of the present invention, the obtained concentration values , and the calculated total flow ,in The cross-sectional area of ​​the flow channel is given by the structural design and calibration. This is based on the concentration deviation. Adjusting the opening of the flow control valve 5 in at least one upstream branch of the process gas path includes: calculating the corresponding valve adjustment amount based on the concentration deviation, and updating the opening of the flow control valve 5 in real time through at least one of proportional regulation, integral regulation, or proportional-integral regulation, so that the concentration of the mixed gas after the flow of each branch is superimposed gradually approaches the target concentration. Specifically, the valve opening correction amount is calculated by a control algorithm (PI or PID) and the flow control valves of one or more upstream branches are updated in real time through the actuator; simultaneously... The flow rate is compared in real time with the sum of the setpoints of all upstream branches, ∑Q. If the difference exceeds a preset threshold, it is determined to be a possible flow controller malfunction, gas leakage, or valve malfunction, triggering a safety interlock to ensure the controllability of the atmosphere within the process chamber. To enhance system robustness, this embodiment introduces a state observer into the control loop to quickly locate valve execution deviations and MFC anomalies. After anomaly detection, a backup branch is activated or the process is switched to a safer process formulation to reduce losses.

[0068] In some specific embodiments of the present invention, a flow controller is provided on the branch line and electrically connected to the flow control valve 5; when the deviation exceeds a preset error threshold, it is determined that at least one of the following abnormal conditions exists: the flow controller of the branch line is inaccurate or malfunctioning, gas line leakage, or the flow control valve 5 of the branch line malfunctions. In some specific embodiments of the present invention, the triggering of the safety interlock includes at least one of the following operations: sending an alarm signal to the upper unit, automatically shutting off the gas supply to the main gas line or the abnormal branch line, or terminating the current process flow.

[0069] Secondly, referring to Figures 3-5 In some embodiments of the present invention, a monitoring and control system for a semiconductor process gas path is provided, which executes the aforementioned monitoring and control method and enables synchronous monitoring of process gas concentration and total flow rate, as well as closed-loop regulation of the upstream flow control valve 5, without changing the existing gas path hardware structure. For ease of understanding, the entire system is positioned downstream of the gas mixer 2 and upstream of the process chamber, so that the mixed gas entering the chamber can be detected in real time after merging.

[0070] In some specific embodiments of the present invention, the system is the measuring instrument 1. The system includes a monitoring and control unit, which measures the acoustic parameters of the mixed gas passing through the flow channel 11 in a non-contact manner, thereby obtaining the gas concentration and total flow rate. The monitoring and control unit includes the clamp-on ultrasonic time-of-flight measurement module 12, the temperature sensing unit 13, and the pressure sensing unit 14. The clamp-on ultrasonic time-of-flight measurement module 12 is configured to clamp into the gas path, and includes a clamp body 15 and a transducer 16 assembly arranged inside the clamp body 15. The clamp body 15 typically adopts a detachable structure and covers the outside of the gas path flow channel 11, allowing for quick installation without compromising the sealing of the process pipeline. VCR interfaces 4 are provided at both ends of the flow channel 11. The clamp body 15 has an installation space for accommodating the ultrasonic transducer 16, allowing the transducer 16 assembly to couple ultrasonic signals into the flow channel 11 at a fixed interval and fixed angle, achieving simultaneous measurement of propagation time in both the forward and reverse directions.

[0071] In some further embodiments of the present invention, to reduce the interference of the measuring device on the gas flow state, the flow channel 11 adapted to the monitoring and control unit adopts a full-bore zero-pressure-loss structure, and its inner diameter is consistent with the original process pipeline, without forming a sudden expansion or contraction structure, thereby avoiding secondary disturbances in the gas flow field. At the same time, in order to reduce the adsorption reaction of semiconductor process gases (especially fluorine-containing, chlorine-containing, or highly reactive precursor gases) on the pipe wall surface and improve the stability of long-term measurement, an inert passivation layer is provided on the inner wall of the flow channel 11, such as using fluorinated polymers, ceramics, or stable metal oxide materials, so that the gas path can still maintain low adsorption and low residue characteristics in high humidity, high temperature, or corrosive environments.

[0072] In some embodiments of the present invention, the system further includes a flow control unit. The flow control unit is located in each process gas branch upstream of the gas mixer 2, and typically consists of multiple flow control valves 5, each branch having a corresponding target flow setpoint. The system controller 6 can calculate the deviation between the mixed gas concentration measured by the downstream monitoring control unit and the target concentration, and dynamically adjust the opening of the flow control valve 5 of the corresponding branch, so that the supply of each component gas can be compensated in real time, thereby maintaining the stability of the mixed gas ratio.

[0073] In some other embodiments of the present invention, the system controller 6 is also used to perform total flow consistency verification. When a significant deviation occurs between the total flow rate of the mixed gas measured by the monitoring and control unit and the sum of the flow rate setpoints of each branch, for example, if the deviation exceeds the preset allowable range, the system controller 6 can immediately determine that there is an abnormality in the gas path. Possible causes of deviation include malfunction of the flow control valve 5 or mass flow meter of a certain branch, gas leakage, or valve malfunction. To prevent the abnormality from continuing to escalate, the system controller 6 can trigger safety interlock actions, including closing the relevant branch, issuing alarm information, switching to a safe process formula, or blocking the gas supply, thereby ensuring the operational safety of the process chamber.

[0074] In some further embodiments of the invention, an application in a silane-doped gas path is taken as an example. A dilution gas (e.g., nitrogen or argon) and silane gas undergo primary mixing at an upstream gas mixer 2, and the mixed gas is then delivered to the reaction chamber via pipeline. In this type of application, the monitoring and control unit of the present invention can be directly installed on a straight-through process pipeline after the dilution gas and silane gas have completed mixing and before the inlet of the reaction chamber. The installation method allows for seamless connection with the existing pipeline via a VCR connector, resulting in minimal modification requirements to the existing equipment structure.

[0075] In some specific embodiments of the present invention, after installation is completed, the host computer or process controller can send target process parameters to the system controller 6, such as setting the target concentration of silane after mixing to 5.0% vol, and simultaneously setting the target total flow rate to increase in a stepwise manner, for example, gradually increasing from an initial 200 sccm to 2000 sccm. During the gradual increase of gas flow, the monitoring and control unit uses its clamp-on ultrasonic time difference measurement module 12 to continuously measure the propagation time of the mixed gas in the flow channel 11 in both the forward and reverse directions. Combined with the parameters obtained by its internally configured temperature and pressure sensing unit 14, the sound velocity and flow rate are compensated in real time, thereby continuously obtaining the actual concentration of the mixed gas in the entire range of 200–2000 sccm. With total flow Q.

[0076] In some further embodiments of the present invention, the system controller 6 can dynamically adjust the opening of the flow control valve 5 of the silane branch based on the deviation between the real-time concentration X returned by the monitoring and control unit and the target concentration. In the CVD process in which source gas silane participates in the reaction, a small adjustment to the flow rate of the silane branch ensures that the concentration of the mixed gas is maintained near the set value of 5.0% vol at different total flow stages.

[0077] In some other embodiments of the present invention, the system controller 6 can also compare the total flow rate Q measured by the monitoring and control unit with the sum of the flow rate setpoints of each upstream branch, ∑Q, in real time to monitor the gas path operation. When the system detects that the deviation between Q and ∑Q exceeds the allowable threshold, it can immediately trigger a safety interlock, such as issuing an alarm, blocking the silane supply, or switching to a safe operating condition. This enables real-time monitoring of possible branch leaks, abnormal valve operation, or upstream flow rate setpoint deviations.

[0078] In this invention, unless otherwise explicitly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0079] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0080] While embodiments of the present invention have been described in detail above, it will be apparent to those skilled in the art that various modifications and variations can be made to these embodiments. However, it should be understood that such modifications and variations fall within the scope and spirit of the present invention. Furthermore, the present invention described herein may have other embodiments and can be implemented or carried out in various ways.

Claims

1. A monitoring and control method for gas paths in semiconductor processes, characterized in that, Includes the following steps: A measuring instrument is connected in series via an interface and positioned downstream of the gas mixer and upstream of the process chamber in the process gas path. The measuring instrument includes a flow channel, an external clamp-on ultrasonic time difference measurement module, a temperature sensing unit, and a pressure sensing unit. The external clamp-on ultrasonic time difference measurement module is used to detect the propagation time of the mixed gas in the flow channel in both the forward and reverse directions. Combined with the temperature and pressure parameters obtained by the temperature sensing unit and the pressure sensing unit, the sound velocity and flow rate are compensated. Based on the compensated sound velocity, the concentration is inverted to simultaneously obtain the actual concentration value X and the total flow rate Q of the mixed gas. The actual concentration value X is compared with the preset target concentration Y to obtain the concentration deviation. According to the concentration deviation Adjust the opening of the flow control valve of at least one branch upstream of the process gas path to maintain the concentration of the mixed gas entering the process chamber at the target concentration Y; The total flow rate Q is compared in real time with the sum of the flow rate settings of all upstream branches ∑Q. When the deviation exceeds the preset error threshold, a safety interlock is triggered.

2. The monitoring and control method for a semiconductor process gas path according to claim 1, characterized in that, The compensation for sound velocity and flow rate is calculated using the following two-parameter coupled model: in, The compensated speed of sound, The compensated gas flow rate, and These represent the propagation times of the ultrasonic waves in the downstream and upstream directions, respectively; L is the effective acoustic path length between the transducers. This is the temperature compensation factor; As a stress compensation factor; This is a correction factor used to eliminate flow rate deviations caused by temperature gradients.

3. The monitoring and control method for a semiconductor process gas path according to claim 2, characterized in that, The concentration inversion based on the compensated sound velocity includes establishing the following nonlinear inversion equation based on a mixed gas sound velocity model: ； in, The average molar mass of the binary gas mixture; ； in, satisfy: in, The molar concentration of the target component. The compensated speed of sound, The gas constant is... For real-time measured temperature, and The adiabatic index of each component in the binary mixed process gas.

4. The monitoring and control method for a semiconductor process gas path according to claim 3, characterized in that, The concentration inversion process employs a numerical iterative solution method, which is at least one of Newton's iteration method, the bisection method, or the quasi-Newton method, to ensure rapid convergence to a unique physics solution within a preset concentration range.

5. The monitoring and control method for a semiconductor process gas path according to claim 1, characterized in that, According to the concentration deviation The opening degree of the flow control valve for at least one branch upstream of the process gas line includes: The corresponding valve adjustment amount is calculated based on the concentration deviation, and the real-time opening degree of the flow control valve is updated through at least one of proportional regulation, integral regulation, or proportional-integral regulation, so that the concentration of the mixed gas after the flow of each branch is superimposed gradually approaches the target concentration.

6. The monitoring and control method for a semiconductor process gas path according to claim 1, characterized in that, A flow controller is installed on the branch line and is electrically connected to the flow control valve; When the deviation exceeds the preset error threshold, it is determined that at least one of the following abnormal situations exists: the flow controller of the branch is inaccurate or malfunctioning, the gas line is leaking, or the flow control valve of the branch is malfunctioning.

7. The monitoring and control method for a semiconductor process gas path according to claim 1, characterized in that, The triggering of the safety interlock includes at least one of the following operations: sending an alarm signal to the upper unit, automatically shutting off the gas supply to the main gas circuit or abnormal branch circuit, or terminating the current process flow.

8. A monitoring and control system for a semiconductor process gas path, used to execute the monitoring and control method for a semiconductor process gas path as described in any one of claims 1-7, characterized in that, include: A monitoring and control unit is connected in series downstream of the gas mixer and upstream of the process chamber in the process gas path. It is used to synchronously measure the concentration and total flow rate of the mixed gas in a non-contact manner. The monitoring and control unit includes the clamp-on ultrasonic time difference measurement module, the temperature sensing unit, and the pressure sensing unit. The flow control unit includes the flow control valves disposed on each gas branch upstream of the gas mixer; The system controller is communicatively connected to both the monitoring control unit and the flow control unit. The system controller is used to receive the concentration and total flow rate from the monitoring and control unit, control the opening of the flow control valve to adjust the gas flow rate according to the deviation between the concentration and a preset target concentration, and trigger a safety interlock action according to the deviation between the total flow rate and the sum of the set values ​​of the flow rates of each branch.

9. A monitoring and control system for a semiconductor process gas path according to claim 8, characterized in that, The clamp-on ultrasonic time difference measurement module includes: The clamp body clamps and covers the outside of the flow channel, and the clamp body has an installation space. A transducer assembly includes a pair of ultrasonic transducers disposed within the mounting space.

10. A monitoring and control system for a semiconductor process gas path according to claim 8, characterized in that, The flow channel is a full-bore zero-pressure-loss flow channel, and the inner wall of the flow channel is coated with an inert passivation layer.

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