Method and apparatus for suppressing arcs in plasma cavities and high frequency power supply system

Abstract

The present application relates to a method, apparatus and high frequency power supply system for suppressing an arc in a plasma cavity. The method includes the steps of: obtaining a reflection coefficient in the plasma cavity by arc detection sampling, the reflection coefficient including an instantaneous reflection coefficient and an average reflection coefficient; comparing an absolute value of a difference between the instantaneous reflection coefficient and the average reflection coefficient with a predetermined reflection coefficient threshold; when it is determined that an arc occurs in the plasma cavity according to the comparison result, instructing a state machine to lock the last operating parameter corresponding to a restoration node of the high frequency power supply system, suspend the arc detection sampling, and cut off the power output of the output end coupled to the plasma cavity by a control module of a PID controller; and instructing the control module of the PID controller to restore the power output of the output end according to the operating parameters and restore the arc detection sampling after the arc in the plasma cavity is removed. Thus, a highly accurate arc suppression process in the cavity is realized.

Description

[Technical field]

[0001] The present application relates to the technical field of radio frequency system sensing and control, and more particularly to a method, apparatus and radio frequency power system for suppressing arcs in a plasma cavity. [Background technology]

[0002] As the technology of RF power supplies develops, the fields of application are expanding from the traditional vacuum field to semiconductors and even other fields such as cosmetics. The so-called RF power supply system usually includes a RF power supply and a plasma cavity. The RF power supply is a power supply attached to the plasma cavity, and is often applied to equipment such as RF sputtering, PECVD chemical vapor deposition, and reactive ion etching. In practical applications, if an arc occurs in the plasma cavity, it will reduce the product yield and also lead to electromagnetic interference (EMI) problems. Regarding the occurrence of an arc in a plasma cavity, the conventional suppression technology mainly uses a judgment method that detects the instantaneous change rate of voltage and current, while the arc extinguishing technology uses a hardware device to perform arc extinguishing and suppress the arc by designing an arc suppressor. However, in the process of realization, the inventor discovered that at least the conventional technology has a technical problem that the accuracy of arc suppression is not high. Summary of the Invention [Problem to be solved by the invention]

[0003] Based on the above, in order to address the above technical problems, it is necessary to provide a method for suppressing an arc in a plasma cavity, an apparatus for suppressing an arc in a plasma cavity, a high frequency power supply system, and a computer-readable storage medium, which can significantly improve the accuracy of suppressing an arc in the cavity.

[0004] To achieve the above objectives, the present application provides the following technical solutions: [Means for solving the problem]

[0005] In one aspect, a method for suppressing an arc in a plasma cavity is provided, the method including: acquiring a reflection coefficient in the plasma cavity by arc detection sampling, the reflection coefficient including an instantaneous reflection coefficient and an average reflection coefficient; comparing an absolute value of a difference between the instantaneous reflection coefficient and the average reflection coefficient with a predetermined reflection coefficient threshold; when it is determined that an arc has occurred in the plasma cavity based on the comparison result, instructing by a state machine to lock a last operating parameter corresponding to a restoration node of a high frequency power system, suspend the arc detection sampling, and cut off a power output of an output end coupled to the plasma cavity by a control module of a PID controller; and after the arc in the plasma cavity is removed, instructing the control module of the PID controller to restore the power output of the output end and restore the arc detection sampling based on the operating parameters.

[0006] In one embodiment, the process of determining whether an arc has occurred within the plasma cavity based on the comparison result includes determining whether an arc has occurred within the plasma cavity based on the absolute value of the difference being less than a predetermined reflection coefficient threshold and satisfying a predetermined analytical decision condition.

[0007] In one embodiment, the predetermined analytical decision condition includes determining that no arc is occurring in the plasma cavity if the absolute value of the difference is less than a predetermined reflection coefficient threshold for N consecutive times, where N is a positive integer greater than or equal to 2.

[0008] In one embodiment, the predetermined analytical determination condition includes determining that no arc is occurring in the plasma cavity if the absolute value of the difference exceeds a predetermined reflection coefficient threshold M non-consecutive times within a predetermined time period, where M is a positive integer greater than or equal to 1.

[0009] In one embodiment, the predetermined analytical decision condition includes determining that an arc has occurred in the plasma cavity if the absolute value of the difference exceeds a predetermined reflection coefficient threshold once.

[0010] In one embodiment, the predetermined analytical decision condition includes determining that an arc has occurred in the plasma cavity if the absolute value of the difference exceeds a predetermined reflection coefficient threshold N consecutive times, where N is a positive integer greater than or equal to 2.

[0011] In one embodiment, the detection period of the arc detection sampling includes a plurality of detection periods in ascending order, and the predetermined reflection coefficient threshold is a manually set coefficient threshold or a coefficient threshold adaptively set by the system, and the method further includes extending the detection period from the shortest detection period to a next longer detection period if the frequency of arc occurrence in the plasma cavity is lower than the predetermined frequency threshold, and otherwise, keeping the detection period unchanged and adaptively increasing the coefficient threshold adaptively set by the system by a multiple or a constant value.

[0012] In one embodiment, the method further includes a step of causing the PID controller to maintain operation in a normal control state when it is determined based on the comparison result that no arc has occurred in the plasma cavity, where the normal control state includes: maintaining a current operating state of the control module; continuing arc detection sampling to obtain a reflection coefficient in the plasma cavity; recording an average reflection coefficient in the current normal operating state; recording operating parameters for the control module; recording operating variable parameters of the unit device at the output end; and setting the currently normally operating time node as a restoration node and continuously updating it.

[0013] In one embodiment, the process of instructing the state machine to lock the final operating parameters corresponding to the restoration node of the high frequency power system includes: instructing the state machine to lock the final average reflection coefficient under normal operating conditions, instructing the control module to lock the operating parameters, and instructing the output end to lock the operating variable parameters of each unit device.

[0014] In one embodiment, the step of obtaining reflection coefficients in the plasma cavity by arc detection sampling includes the steps of: obtaining instantaneous reflection coefficients by adopting periodic, fixed-point sampling; and calculating an average reflection coefficient from all currently sampled instantaneous reflection coefficients, wherein each sampling, average value calculation, and threshold comparison are synchronous multi-threaded processes in a single time interval.

[0015] In another aspect, an apparatus for suppressing an arc in a plasma cavity is provided, the apparatus including: a detection sampling module for obtaining a reflection coefficient in the plasma cavity by arc detection sampling, the reflection coefficient including an instantaneous reflection coefficient and an average reflection coefficient; a coefficient comparison module for comparing an absolute value of a difference between the instantaneous reflection coefficient and the average reflection coefficient with a predetermined reflection coefficient threshold; an arc extinguishing module for instructing, by a state machine, when it is determined that an arc has occurred in the plasma cavity based on a comparison result, to lock a last operating parameter corresponding to a restoration node of the high frequency power system, suspend the arc detection sampling, and cut off a power output of an output end coupled to the plasma cavity by a control module of a PID controller; and an output recovery module for instructing, based on the operating parameters, the control module of the PID controller to restore the power output of the output end and restore the arc detection sampling after the arc in the plasma cavity is removed.

[0016] In still another aspect, a high frequency power supply system is provided, the high frequency power supply system including: a high frequency power supply; a PID controller; and a plasma cavity, the high frequency power supply being electrically connected to the plasma cavity through the PID controller, the PID controller being used to realize an arc suppression processing step including: acquiring a reflection coefficient in the plasma cavity through arc detection sampling, the reflection coefficient including an instantaneous reflection coefficient and an average reflection coefficient; comparing an absolute value of a difference between the instantaneous reflection coefficient and the average reflection coefficient with a predetermined reflection coefficient threshold; if it is determined based on the comparison result that an arc has occurred in the plasma cavity, locking a last operating parameter corresponding to a restoration node of the high frequency power supply system, suspending the arc detection sampling, and cutting off a power output of an output end coupled to the plasma cavity; and after the arc in the plasma cavity is removed, restoring the power output of the output end based on the operating parameters and restoring the arc detection sampling.

[0017] In yet another aspect, there is provided a computer readable storage medium having stored thereon a computer program which, when executed by a processor, implements the steps of the method for suppressing an arc in a plasma cavity according to any one of the preceding claims.

[0018] One of the above technical solutions has the following advantages and beneficial effects:

[0019] According to the above-mentioned method, device and high frequency power supply system for suppressing an arc in a plasma cavity, the instantaneous and average reflection coefficients in the plasma cavity are obtained by arc detection sampling, and compared with a predetermined reflection coefficient threshold value to accurately determine whether an arc occurs in the plasma cavity. If it is determined that an arc occurs in the plasma cavity, the last operating parameters corresponding to the restoration node of the high frequency power supply system are locked, the arc detection sampling is suspended, and the state machine instructs the control module of the PID controller to cut off the power output of the output end coupled to the plasma cavity, so as to suspend the power output of the high frequency power supply to the plasma cavity. After the arc in the plasma cavity is removed, the power output of the output end is restored according to the operating parameters, and the control module of the PID controller is instructed to restore the arc detection sampling, so as to restore the power output of the high frequency power supply to the plasma cavity. Thus, the arc in the plasma cavity is suppressed with high accuracy.

[0020] Compared with the conventional method, the above solution greatly improves the accuracy of judging whether an arc occurs by using a mechanism of comparing the reflection coefficient average value (also called gamma average value) with a critical value. If it is judged that an arc occurs, the state machine instructs to lock the last operating parameters corresponding to the restoration node of the system, suspend the arc detection, and suspend the power output. Thus, after the arc in the cavity is removed, the power output can be accurately and quickly restored based on the locked operating parameters, and a highly accurate intracavity arc suppression process can be realized, and the cost of arc suppression can be reduced, the efficiency can be improved, and the adaptability can be increased.

[0021] In order to more clearly describe the technical solutions in the embodiments of the present application or the prior art, the following will briefly describe the drawings necessary for describing the embodiments or the prior art. Of course, the drawings described below are part of the embodiments of the present application, and those skilled in the art can think of other drawings based on these drawings without any creative efforts. [Brief description of the drawings]

[0022] [Figure 1] 1 is a schematic environmental flow diagram of a method for suppressing an arc in a plasma cavity in one embodiment. [Diagram 2] FIG. 4 is a schematic diagram of sampling of instantaneous values ​​in an embodiment. [Diagram 3] FIG. 1 is a schematic diagram of an ARC suppression step in one embodiment. [Figure 4] 1 is a flowchart of an ARC monitoring and suppression process in one embodiment. [Diagram 5] FIG. 2 is a block diagram of a modular structure of an arc suppression device within a plasma cavity in one embodiment. [Figure 6] FIG. 2 is a schematic diagram of a structural frame of a high frequency power supply system according to an embodiment. [Figure 7] FIG. 2 is a schematic diagram illustrating the configuration of an ARC processing module in one embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] In order to make the objectives, technical solutions and advantages of the present application clearer and easier to understand, the present application will be further described in detail below with reference to the drawings and examples. It should be understood that the specific examples described herein are only for the purpose of interpreting the present application, and are not intended to limit the present application.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application pertains. The terms used in the specification of this application in this specification are merely for the purpose of describing specific examples and are not intended to limit the scope of this application.

[0025] It should be noted that the "embodiment" referred to in this specification means that the specific features, structures, or characteristics described in the embodiment may be included in at least one embodiment of the present invention. The term appears in various places in the specification, but does not necessarily refer to the same embodiment, nor is it an exclusively independent or alternative embodiment to other embodiments.

[0026] It will be understood by those skilled in the art that the embodiments described herein may be combined with other embodiments. As used in the specification of this disclosure and the appended claims, the term "and / or" means and includes any and all possible combinations of one or more of the associated listed items.

[0027] In the research for practical application, the inventor found that if the occurrence of an arc phenomenon is judged only by detecting the rate of change of the current and voltage, a misjudgment may occur, which may affect the normal operation of the system. Although the arc phenomenon can be effectively suppressed by adopting a specialized arc extinguishing device, it increases the complexity and manufacturing cost of the system, and in the usage scenario where only a small arc occurs, the need for an arc extinguishing device is not high. In addition, the arc extinguishing device needs to be designed for a specific scene, and there are many types of arcs in the plasma cavity, so a single arc extinguishing device is difficult to be effective. Therefore, in response to at least the technical problem of the prior art that the accuracy of arc suppression is not high, the present application proposes a novel method for suppressing arcs in the plasma cavity, and can realize highly accurate suppression of arcs in the cavity.

[0028] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the preferred embodiments of the present invention will be described in detail with reference to the drawings showing the preferred embodiments of the present invention.

[0029] In one embodiment, a method for suppressing an arc in a plasma cavity, which can be applied to various high frequency power supply systems, is provided, as shown in Figure 1. The method includes the following steps S12 to S18.

[0030] In S12, the reflection coefficients in the plasma cavity are obtained by arc detection sampling, and the reflection coefficients include an instantaneous reflection coefficient and an average reflection coefficient.

[0031] Arc detection sampling is understood to be a detection means for easily calculating the reflection coefficient (which may be referred to as a gamma value in this specification) in the plasma cavity by sampling measurement information of the plasma cavity using a sensor system or an external sensor device existing in the system. The measurement information to be sampled may be at least one or a combination of a voltage value, a current value, a power value, a cavity impedance value, and a source impedance value, as long as the reflection coefficient in the plasma cavity can be accurately measured. The instantaneous reflection coefficient is the current reflection coefficient in the plasma cavity sampled at the present time, and the average reflection coefficient is the average coefficient value calculated from all the reflection coefficients sampled up to the present time.

[0032] Specifically, during operation of the RF power system, arc detection sampling is performed on the system (mainly the relevant electrical parameters of the plasma cavity) to obtain an instantaneous reflection coefficient within the plasma cavity and calculate a corresponding average reflection coefficient.

[0033] At S14, the absolute value of the difference between the instantaneous reflection coefficient and the average reflection coefficient is compared with a predetermined reflection coefficient threshold value.

[0034] For convenience of explanation, the instantaneous reflection coefficient is Γ cur and the average reflection coefficient is Γ aver and the comparison process can be written as |Γ cur -Gamma aver |<Γ th It will be appreciated that it can be stated that it is determined whether the following expression is true: if true, it indicates that the system is currently operating normally and no arc has occurred in the cavity; if false, it indicates that the system is currently operating abnormally and an arc has occurred in the cavity.

[0035] The process for accurately determining whether an arc has occurred within the cavity through the arc detection sampling, gamma average calculation and comparison process described above may be referred to as ARC monitoring.

[0036] In S16, if it is determined based on the comparison result that an arc has occurred in the plasma cavity, the state machine instructs to lock the last operating parameters corresponding to the restoration node of the high frequency power system, suspend the arc detection sampling, and shut off the power output of the output end coupled to the plasma cavity via the control module of the PID controller.

[0037] In the system, it is understood that the state machine is a state control unit that instructs each module of the system to lock and / or unlock the operating parameters. During the operation of the system, the PID controller can have a normal control state and a shut-off control state. The PID controller samples the instantaneous value of gamma and calculates the average value. cur -Gamma aver |<Γ th and obtain the instantaneous gamma value and the comparison result. If it is determined that no arc occurs, it is in a normal control state, in which the PID controller maintains the current operation of the control module and continuously detects the gamma value, and at the same time, records each operating parameter at which the system operates normally at the current time node, which may be a restoration node, and each data at this restoration node is continuously updated under the normal control state.

[0038] If it is determined that an arc occurs in the plasma cavity, the PID controller is switched to a shutoff control state, under which the state machine also switches to an operating state to instruct each module to lock the last operating parameter corresponding to the restoration node and suspend arc detection sampling (ARC monitoring) for a certain time X (the length of the time X can be set according to the potential drop time+zero potential time+potential rise time of the plasma cavity). Meanwhile, the control module of the PID controller is still in an operating state and cuts off the power output of the output end coupled to the plasma cavity to cut off the high frequency power output of the high frequency power source to the plasma cavity, and after the power output is cut off, the plasma cavity experiences a potential drop, a certain time (zero potential time) of quiescence, and a subsequent potential re-rise time (potential rise time) after power recovery.

[0039] At S18, after the arc in the plasma cavity is cleared, instruct the control module of the PID controller to restore power output at the output end and resume arc detection sampling based on the operating parameters.

[0040] It is understood that after the control module of the PID controller cuts off the power output of the output end coupled to the plasma cavity, the potential of the plasma cavity drops and remains at zero potential for a certain time, eliminating the arc generated in the cavity. After a certain time of quiescence (the length of time can be set according to the statistical rule of the shortest time to eliminate the arc / extinguishing time in practical application), the arc is eliminated, at this time, the state machine switches the working state to make each module restore the normal working state according to the working parameters of the last restoration node locked before the arc is extinguished, instructs the control module of the PID controller to restore the power output coupled to the plasma cavity, and instructs the PID controller to restore the ARC monitoring, thus proceeding to the next round of the arc monitoring and suppression working process. As can be appreciated by those skilled in the art, if it is observed that arcing still occurs within the cavity after operation is restored, the above operations can be repeated to suppress the arc, and the zero potential time can be selectively extended to achieve a better arc-extinguishing effect.

[0041] In the above-mentioned method for suppressing an arc in a plasma cavity, the instantaneous and average reflection coefficients in the plasma cavity are obtained by arc detection sampling, and then compared with a predetermined reflection coefficient threshold value to accurately determine whether an arc occurs in the plasma cavity. If it is determined that an arc occurs in the plasma cavity, the last working parameters corresponding to the restoration node of the high frequency power supply system are locked, the arc detection sampling is suspended, and the control module of the PID controller cuts off the power output of the output end coupled to the plasma cavity, i.e., the high frequency power supply suspends the power output to the plasma cavity, and after the arc in the plasma cavity is removed, the control module of the PID controller is instructed according to the working parameters to restore the power output of the output end and restore the arc detection sampling, i.e., the high frequency power supply restores the power output to the plasma cavity. Thus, the arc in the plasma cavity is suppressed with high accuracy.

[0042] Compared with the conventional method, the above solution uses a mechanism of comparing the reflection coefficient average value (which may be called the gamma average value) with a critical value to greatly improve the accuracy of judging whether an arc occurs. If it is judged that an arc occurs, the state machine instructs to lock the last operating parameters corresponding to the restoration node of the system, suspend the arc detection, and suspend the power output. Thus, after the arc in the cavity is removed, the power output can be accurately and quickly restored based on the locked operating parameters, and a highly accurate intracavity arc suppression process can be realized, and the cost of arc suppression can be reduced, the efficiency can be improved, and the adaptability can be improved.

[0043] In one embodiment, the method of determining whether the arc in the plasma cavity has been removed may be, but is not limited to, detecting energy in the cavity and determining whether the remaining energy in the cavity is zero or lower than a predetermined energy threshold to determine whether the arc has been removed (if the remaining energy in the cavity is zero or lower than a predetermined energy threshold, it can be determined that the arc has been removed, and if not, it can be determined that it has not been removed), or determining that the arc in the cavity has been removed after a predetermined time has elapsed since the power output was cut off, or visually determining whether the arc in the cavity has been removed (if no arc is observed in the cavity, it is determined that the arc has been removed, and if not, it is determined that it has not been removed). Other methods of determination may be used as long as they can accurately determine whether the arc in the cavity has been removed. By determining the arc state in the cavity using the above method, the state machine can be immediately and accurately instructed to switch working states and each module can be instructed to restore the working state before the lockup, thereby reducing the power interruption time and improving the overall arc suppression process efficiency.

[0044] In one embodiment, the above step S12 may specifically include a step of obtaining instantaneous reflection coefficients by adopting periodic, fixed-point sampling, and a step of calculating an average reflection coefficient from all currently sampled instantaneous reflection coefficients, where each sampling, average value calculation, and threshold comparison are all synchronous multi-threaded processes in a single time interval.

[0045] Specifically, periodic and fixed-point sampling is adopted for detecting and sampling the instantaneous reflection coefficient, and all the sampled values ​​are available and are used to calculate the gamma average value. In addition, for each sampling, coefficient and average value calculation, and threshold comparison process, in this embodiment, as shown in Figure 2, the PID controller adopts synchronous multi-thread processing with a single time interval to achieve the same purpose at multiple locations synchronously, which further improves the reliability of intra-cavity reflection detection and arc judgment.

[0046] In one embodiment, the process of determining whether an arc has occurred in the plasma cavity based on the comparison result in step S16 above may include determining whether an arc has occurred in the plasma cavity based on the absolute value of the difference being less than a predetermined reflection coefficient threshold and satisfying a predetermined analytical judgment condition.

[0047] In the above embodiment, |Γ cur -Gamma aver |<Γ th It can be understood that whether an arc has occurred in the cavity can be directly determined by determining whether |Γ cur -Gamma aver |<Γ th is established and a predetermined analytical judgment condition is satisfied, thereby making it possible to more accurately judge whether an arc has occurred in the cavity.

[0048] In one embodiment, optionally, the predetermined analysis judgment condition may include determining that no arc is occurring in the plasma cavity if the absolute value of the difference is less than a predetermined reflection coefficient threshold value N consecutive times, where N is a positive integer greater than or equal to 2.

[0049] Specifically, |Γ is cur -Gamma aver |<Γ th If it is determined that this is the case, it can be determined that no arc is currently occurring within the plasma cavity.

[0050] In one embodiment, optionally, the predetermined analysis judgment condition may include determining that no arc is occurring in the plasma cavity if the absolute value of the difference exceeds a predetermined reflection coefficient threshold value M non-consecutive times within a predetermined time period, where M is a positive integer greater than or equal to 1.

[0051] Specifically, within a certain period of time (i.e., a predetermined period, the specific length of which can be determined according to the monitoring experience in practical applications or the statistical situation of the monitoring history data), |Γ is discontinuously detected a limited number of times M or less (including once). cur -Gamma aver |>Γ th If so, it can be determined that no arc is currently occurring within the plasma cavity.

[0052] In one embodiment, optionally, the predetermined analysis judgment condition may further include determining that an arc has occurred in the plasma cavity if the absolute value of the difference exceeds the predetermined reflection coefficient threshold once.

[0053] Specifically, once |Γ cur -Gamma aver |>Γ th If so, it can be determined that an arc has occurred within the plasma cavity.

[0054] In one embodiment, optionally, the predetermined analytical judgment condition may include determining that an arc has occurred in the plasma cavity when the absolute value of the difference exceeds a predetermined reflection coefficient threshold N consecutive times, where N is a positive integer greater than or equal to 2.

[0055] Specifically, if |Γ occurs multiple times (including twice) in succession, cur -Gamma aver |>Γ th If so, it can be determined that an arc has occurred within the plasma cavity.

[0056] It should be noted that the above-mentioned predetermined analysis judgment conditions may be further combined as long as the combination is not made up of mutually exclusive conditions.

[0057] In one embodiment, the detection period of the arc detection sampling includes a plurality of detection periods in ascending order.The predetermined reflection coefficient threshold is a coefficient threshold set manually or a coefficient threshold adaptively set by the system. The method for suppressing arcs in the plasma cavity may further include extending the detection period from the shortest detection period to a next longer detection period if the frequency of arcs occurring in the plasma cavity is lower than a set frequency threshold, and otherwise keeping the detection period unchanged and adaptively increasing the coefficient threshold adaptively set by the system by a multiple or a constant value.

[0058] Specifically, a predetermined reflection coefficient threshold Γ th may be set manually (for example, based on operation experience or monitoring history data, etc.), or may be adaptively set by the system. Here, when the system adaptively sets the initial value Γ th Set |Γ cur -Gamma aver |<Γ th An initial comparison process can be introduced, and the initial value Γ th may be manually set, and Γ cur and Γ aver The time may be calculated from dynamic or historical data.

[0059] In actual monitoring, for example, 8 us, 16 us, 32 us, ... are used, but not limited to these. According to a plurality of predetermined detection periods in ascending order, the shortest detection period, for example, 8 us, is first set, and within the shortest detection period, |Γ cur -Gamma aver |<Γ thIf the frequency of arc occurrence is lower than the predetermined frequency threshold, the detection period is extended to the next longer detection period, for example, 16us or 32us, and the coefficient threshold adaptively set by the system does not need to be changed. If the frequency of arc occurrence is higher than the predetermined frequency threshold within the shortest detection period, Γ th For example, the value of |Γ is increased by a factor or a constant value. cur -Gamma aver We obtain the dynamic maximum of | and then double it or increase it by a constant value to obtain the adjusted Γ th Let us assume that.

[0060] Through the above steps, the system can realize adaptive coefficient threshold adjustment, and the accuracy of judging whether an arc occurs can be further improved.

[0061] In one embodiment, the method for suppressing an arc in the plasma cavity further includes, when it is determined based on the comparison result that no arc has occurred in the plasma cavity, causing the PID controller to maintain operation in a normal control state, where the normal control state includes maintaining a current operating state of the control module, continuing arc detection sampling to obtain a reflection coefficient in the plasma cavity, recording an average reflection coefficient in the current normal operating state, recording operating parameters for the control module, recording operating variable parameters of a unit device at the output end, and setting a currently normally operating time node as a restoration node to continuously update.

[0062] Specifically, under the normal control state of the PID controller, the PID controller acquires the instantaneous value of gamma, calculates its average value, and cur -Gamma aver |<Γ thIf it is determined that no arc has occurred, the normal control state is maintained. At this time, the PID controller maintains the current operation of the control module to continuously monitor the gamma value, and at the same time, records the operation parameters at the current time node, which are (a) the normal operating gamma average value, (b) the operation parameters of the control module of the PID controller to the output end, and (c) the operation variable parameters of the unit device that outputs power at the output end, and this time node is set as a restoration node, and the data at this restoration node is continuously updated in the normal control state.

[0063] In one embodiment, the process of instructing the state machine to lock the last operating parameters corresponding to the restoration node of the high frequency power system in step S16 is specifically as follows: The state machine may instruct the control module to lock the last average reflection coefficient under normal operating conditions, and may include a process of instructing the output terminal to lock the operating variable parameters of each unit device.

[0064] Specifically, when it is determined that an arc has occurred, the PID controller is switched to an interruption control state, and its state machine also switches its operating state to instruct each module to lock the last operating parameters corresponding to the restoration node, for example, instructing the module for calculating the gamma average value to lock the gamma average value, instructing the control module of the PID controller to lock the operating parameters, and instructing the output end coupled to the plasma cavity to lock the operating variable parameters of the unit device, and at the same time, the state machine instructs the PID controller to suspend monitoring of the gamma value for a certain time X (including the potential drop time + zero potential + potential rise).

[0065] As shown in Figure 3, which is a schematic diagram of ARC suppression at each stage, the entire ARC generation process can be divided into seven stages, A to G, and the meaning and processing method of each stage can be shown in Table 1. Through the above steps, by utilizing the parameter lock control mechanism provided by the state machine, the system can ensure that the system recovers to the normal working state as quickly as possible after the arc is removed.

[0066] [Table 1]

[0067] As shown in Figure 4, which is a schematic diagram of one of the ARC treatment processes, the whole process can be divided into two parts: the Gamma average calculation and comparison part, and the PID storage and suspension part. The above processing method realizes high-precision detection and suppression of ARC, and can quickly restore the system operation after extinguishing the arc, with low extinguishing costs.

[0068] It should be understood that although the steps in the flow charts of Figures 1 and 4 are shown in sequence as indicated by arrows, the steps are not necessarily performed in the order indicated by the arrows, and unless expressly described herein, the performance of the steps is not limited to a strict order and may be performed in other orders. In addition, at least some of the steps in Figures 1 and 4 may include multiple sub-steps or multiple stages, which are not necessarily performed and completed at the same time but may be performed at different times, and the order in which these sub-steps or stages are performed is not necessarily in this order but may be performed alternately or in a staggered manner with other steps or at least some of the sub-steps or stages of other steps.

[0069] In one embodiment, as shown in FIG. 5, an apparatus 100 for suppressing an arc within a plasma cavity is provided, which includes a detection sampling module 11, a coefficient comparison module 13, an arc extinguishing module 15, and a power recovery module 17. Here, the detection sampling module 11 is used for obtaining the reflection coefficient in the plasma cavity by the arc detection sampling, where the reflection coefficient includes an instantaneous reflection coefficient and an average reflection coefficient. The coefficient comparison module 13 is used for comparing the absolute value of the difference between the instantaneous reflection coefficient and the average reflection coefficient with a predetermined reflection coefficient threshold value. When the arc extinguishing module 15 determines that an arc occurs in the plasma cavity according to the comparison result, it is used for instructing the state machine to lock the last operating parameter corresponding to the restoration node of the high frequency power system, suspend the arc detection sampling, and cut off the power output of the output end coupled to the plasma cavity by the control module of the PID controller. The output recovery module 17 is used for instructing the control module of the PID controller to restore the power output of the output end and restore the arc detection sampling according to the operating parameters after the arc in the plasma cavity is removed.

[0070] The above-mentioned arc suppression device 100 in the plasma cavity obtains the instantaneous and average reflection coefficients in the plasma cavity through arc detection sampling, and then compares them with a predetermined reflection coefficient threshold value to accurately determine whether an arc occurs in the plasma cavity. If it is determined that an arc occurs in the plasma cavity, the last operating parameters corresponding to the restoration node of the high frequency power supply system are locked, the arc detection sampling is suspended, and the control module of the PID controller cuts off the power output of the output end coupled to the plasma cavity, i.e., the high frequency power supply suspends the power output to the plasma cavity, and after the arc in the plasma cavity is removed, the control module of the PID controller is instructed according to the operating parameters to restore the power output of the output end and restore the arc detection sampling, i.e., the high frequency power supply restores the power output to the plasma cavity. Thus, the arc in the plasma cavity is suppressed with high accuracy.

[0071] Compared with the conventional method, the above solution uses a mechanism of comparing the reflection coefficient average value (which may be called the gamma average value) with a critical value to greatly improve the accuracy of judging whether an arc occurs. If it is judged that an arc occurs, the state machine instructs to lock the last operating parameters corresponding to the restoration node of the system, suspend the arc detection, and suspend the power output. Thus, after the arc in the cavity is removed, the power output can be accurately and quickly restored based on the locked operating parameters, and a highly accurate intracavity arc suppression process can be realized, and the cost of arc suppression can be reduced, the efficiency can be improved, and the adaptability can be improved.

[0072] In one embodiment, the process of determining whether an arc has occurred within the plasma cavity based on the comparison result includes determining whether an arc has occurred within the plasma cavity based on the absolute value of the difference being less than a predetermined reflection coefficient threshold and satisfying a predetermined analytical decision condition.

[0073] In one embodiment, the predetermined analytical decision condition includes determining that no arc is occurring in the plasma cavity if the absolute value of the difference is less than a predetermined reflection coefficient threshold for N consecutive times, where N is a positive integer greater than or equal to 2.

[0074] In one embodiment, the predetermined analytical determination condition includes determining that no arc is occurring in the plasma cavity if the absolute value of the difference exceeds a predetermined reflection coefficient threshold M non-consecutive times within a predetermined time period, where M is a positive integer greater than or equal to 1.

[0075] In one embodiment, the predetermined analytical decision condition includes determining that an arc has occurred in the plasma cavity if the absolute value of the difference exceeds a predetermined reflection coefficient threshold once.

[0076] In one embodiment, the predetermined analytical decision condition includes determining that an arc has occurred in the plasma cavity if the absolute value of the difference exceeds a predetermined reflection coefficient threshold N consecutive times, where N is a positive integer greater than or equal to 2.

[0077] In one embodiment, the detection period of the arc detection sampling includes a plurality of detection periods in ascending order, and the predetermined reflection coefficient threshold is a manually set coefficient threshold or a coefficient threshold adaptively set by the system, and the method further includes extending the detection period from the shortest detection period to a next longer detection period if the frequency of arc occurrence in the plasma cavity is lower than the set frequency threshold, and otherwise, keeping the detection period unchanged, and adaptively increasing the coefficient threshold adaptively set by the system by a multiple or a constant value.

[0078] In one embodiment, the method further includes, when it is determined based on the comparison result that no arc has occurred in the plasma cavity, causing the PID controller to maintain operation in a normal control state, where the normal control state includes: maintaining a current operating state of the control module; continuing arc detection sampling to obtain a reflection coefficient in the plasma cavity; recording an average reflection coefficient in the current normal operating state; recording operating parameters for the control module; recording operating variable parameters of the unit device at the output end; and setting the currently normally operating time node as a restoration node and continuously updating it.

[0079] In one embodiment, the process of instructing the state machine to lock the final operating parameters corresponding to the restoration node of the high frequency power system includes: instructing the state machine to lock the final average reflection coefficient under normal operating conditions, instructing the control module to lock the operating parameters, and instructing the output end to lock the operating variable parameters of each unit device.

[0080] In one embodiment, the step of obtaining the reflection coefficient in the plasma cavity by arc detection sampling includes the steps of: obtaining instantaneous reflection coefficients by adopting periodic, fixed-point sampling; and calculating an average reflection coefficient from all currently sampled instantaneous reflection coefficients, wherein each sampling, average value calculation, and threshold comparison are synchronous multi-threaded processes in a single time interval.

[0081] For specific limitations of the plasma cavity arc suppression device 100, reference may be made to the limitations of the plasma cavity arc suppression method described above, and detailed description will be omitted here. Each module in the plasma cavity arc suppression device 100 can be realized entirely or partially by software, hardware, or a combination thereof. Each module may be built into or independent of a PID controller or processor in the high frequency power supply system in the form of hardware, or may be stored in a memory in the high frequency power supply system in the form of software, so that the PID controller or processor can easily call and execute operations corresponding to each module.

[0082] In one embodiment, as shown in Figure 6, a radio frequency power supply system 200 is provided, which includes a radio frequency power supply 22, a PID controller 24, and a plasma cavity 26. The radio frequency power supply 22 is electrically connected to the plasma cavity 26 via the PID controller 24. The PID controller 24 is used to realize the arc suppression processing steps, including the steps of obtaining a reflection coefficient in the plasma cavity through arc detection sampling, where the reflection coefficient includes an instantaneous reflection coefficient and an average reflection coefficient; comparing the absolute value of the difference between the instantaneous reflection coefficient and the average reflection coefficient with a predetermined reflection coefficient threshold; if it is determined that an arc has occurred in the plasma cavity based on the comparison result, locking the last operating parameters corresponding to the restoration node of the high frequency power supply 22 system, suspending the arc detection sampling, and cutting off the power output of the output end coupled to the plasma cavity; and after the arc in the plasma cavity is removed, restoring the power output of the output end based on the operating parameters and restoring the arc detection sampling.

[0083] It is understood that the specific definition of the function realized by the PID controller 24 may refer to the corresponding definition of the arc suppression method in the plasma cavity described above, and detailed description thereof will be omitted here. The specific electrical connection relationship between each member in the high frequency power supply system 200 and their mechanical structure may be similarly understood by referring to the electrical and mechanical structure of the high frequency power supply 22 system existing in the art, and detailed description thereof will be omitted here.

[0084] 7 shows the structure of the ARC processing module divided by the functions to be realized, where the PID controller 24 can be divided into a control module for controlling an output end coupled to the plasma cavity 26, and an ARC processing module as shown in FIG. 7, where the ARC processing module includes an average value calculation unit, a comparison unit, an ARC detection unit, and a state machine. The average value calculation unit can be used to calculate an instantaneous reflection coefficient from the measurement information detected and sampled in real time, and then calculate a corresponding average reflection coefficient. The comparison unit can be used to calculate |Γ cur -Gamma aver | and Γ thThe ARC detection unit can be used to determine whether an arc occurs in the cavity based on the comparison result. A state machine can be used to realize the corresponding instruction control function shown in the above embodiment.

[0085] As can be understood by those skilled in the art, Figures 6 and 7 are merely block diagrams of some product entities and functional structures related to the solutions of the present application, and do not specifically limit the high frequency power system applied to the solutions of the present application. A specific high frequency power system may include more or fewer components than those shown in the above figures, or may combine some components, or have a different component distribution, and the specific details can be determined according to the type of actual high frequency power system.

[0086] The above-mentioned high frequency power supply system 200 obtains the instantaneous and average reflection coefficients in the plasma cavity through arc detection sampling, and then compares them with a predetermined reflection coefficient threshold value to accurately determine whether an arc occurs in the plasma cavity. If it is determined that an arc occurs in the plasma cavity, the state machine locks the last operating parameters corresponding to the restoration node of the high frequency power supply system, suspends the arc detection sampling, and instructs the control module of the PID controller 24 to cut off the power output of the output end coupled to the plasma cavity, i.e., suspends the power output of the high frequency power supply to the plasma cavity 26. After the arc in the plasma cavity is removed, the state machine instructs the control module of the PID controller 24 to restore the power output of the output end and restores the arc detection sampling, i.e., restores the power output of the high frequency power supply to the plasma cavity 26, according to the operating parameters. Thus, a highly accurate suppression of the arc in the plasma cavity is realized.

[0087] Compared with the conventional method, the above solution uses a mechanism of comparing the reflection coefficient average value (which may be called the gamma average value) with a critical value to greatly improve the accuracy of judging whether an arc occurs. If it is judged that an arc occurs, the state machine instructs to lock the last operating parameters corresponding to the restoration node of the system, suspend the arc detection, and suspend the power output. Thus, after the arc in the cavity is removed, the power output can be accurately and quickly restored based on the locked operating parameters, and a highly accurate intracavity arc suppression process can be realized, and the cost of arc suppression can be reduced, the efficiency can be improved, and the adaptability can be improved.

[0088] In one embodiment, a computer-readable storage medium is further provided having stored thereon a computer program which, when executed by a processor, achieves the following steps: obtain a reflection coefficient in the plasma cavity by arc detection sampling, where the reflection coefficient includes an instantaneous reflection coefficient and an average reflection coefficient; compare an absolute value of a difference between the instantaneous reflection coefficient and the average reflection coefficient with a predetermined reflection coefficient threshold; if it is determined based on the comparison result that an arc has occurred in the plasma cavity, instructing by a state machine to lock a last operating parameter corresponding to a restoration node of the high frequency power system, suspend the arc detection sampling, and cause a control module of the PID controller to cut off the power output of the output end coupled to the plasma cavity; and after the arc in the plasma cavity is removed, instructing the control module of the PID controller to restore the power output of the output end and restore the arc detection sampling based on the operating parameters.

[0089] In an embodiment, when the computer program is executed by a processor, additional steps or sub-steps may be implemented in each embodiment of the method for suppressing an arc in a plasma cavity described above.

[0090] It is understandable to those skilled in the art that all or part of the flow of the method of the above embodiment can be realized by the relevant hardware by issuing instructions to the relevant hardware by a computer program, and this computer program may be stored in a non-volatile computer-readable storage medium, and when executed, the flow of each of the above embodiment of the method can be executed. In this regard, all references to memory, storage device, database, or other medium used in each embodiment provided in this application may include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. By way of example and not limitation, RAM can come in a variety of forms, including, but not limited to, Static RAM (SRAM), Dynamic RAM (DRAM), Synchronous DRAM (SDRAM), Double Data Rate SDRAM (DDRSDRAM), Enhanced SDRAM (ESDRAM), Synchlink DRAM (SLDRAM), Memory Bus (Rambus) Direct RAM (RDRAM), Direct Memory Bus Dynamic RAM (DRDRAM), and Memory Bus Dynamic RAM (RDRAM).

[0091] The technical features of the above embodiments may be combined in any manner, and for the sake of brevity, not all possible combinations of the technical features in the above embodiments have been described; however, combinations of these technical features should be considered to be within the scope of the present specification, provided they are not inconsistent.

[0092] The above examples merely represent some embodiments of the present application, and the description is specific and detailed, but should not be understood as limiting the scope of the claims. It should be noted that a person skilled in the art may make various modifications and improvements without departing from the concept of the present application, all of which are within the scope of protection of the present application. Therefore, the patent protection scope of the present application shall be subject to the scope of the attached claims.

Claims

1. acquiring reflection coefficients within the plasma cavity by arc detection sampling, the reflection coefficients including an instantaneous reflection coefficient and an average reflection coefficient; comparing an absolute value of the difference between the instantaneous reflection coefficient and the average reflection coefficient with a predetermined reflection coefficient threshold; If it is determined based on the comparison result that an arc has occurred in the plasma cavity, instructing a state machine to lock a last operating parameter corresponding to a restoration node of a high frequency power system, suspend the arc detection sampling, and shut off the power output of an output end coupled to the plasma cavity via a control module of a PID controller; and after the arc in the plasma cavity is removed, instructing a control module of the PID controller to restore power output at the output and to restore the arc detection sampling based on the operating parameters. A method for suppressing arcs in a plasma cavity.

2. The process of determining whether an arc has occurred in the plasma cavity based on a comparison result includes:

2. The method of claim 1, further comprising determining whether an arc has occurred within the plasma cavity based on the absolute value of the difference being less than the predetermined reflection coefficient threshold and satisfying a predetermined analytical decision condition.

3. The predetermined analysis judgment condition is:

3. The method of claim 2, further comprising determining that no arc is occurring in the plasma cavity when the absolute value of the difference is less than the predetermined reflection coefficient threshold N consecutive times, where N is a positive integer greater than or equal to 2.

4. The predetermined analysis judgment condition is:

4. The method for suppressing an arc in a plasma cavity according to claim 2 or 3, further comprising determining that an arc is not occurring in the plasma cavity when the absolute value of the difference exceeds the predetermined reflection coefficient threshold value M times non-consecutively within a predetermined time period, wherein M is a positive integer equal to or greater than 1.

5. The predetermined analysis judgment condition is:

3. The method of claim 2, further comprising determining that an arc has occurred in the plasma cavity when the absolute value of the difference exceeds the predetermined reflection coefficient threshold once.

6. The predetermined analysis judgment condition is:

6. The method for suppressing an arc in a plasma cavity according to claim 2, 3 or 5, further comprising determining that an arc has occurred in the plasma cavity when the absolute value of the difference exceeds the predetermined reflection coefficient threshold N consecutive times, where N is a positive integer greater than or equal to 2.

7. The detection period of the arc detection sampling includes a plurality of detection periods in ascending order, and the predetermined reflection coefficient threshold is a coefficient threshold set manually or a coefficient threshold adaptively set by a system; The method comprises: if the frequency of arcing in the plasma cavity is less than a set frequency threshold from the shortest detection period, extending the detection period to a next longer detection period; 2. The method of claim 1, further comprising: if not, not changing the detection period and adaptively increasing the coefficient threshold adaptively set by the system by a multiple or a constant value.

8. If it is determined based on the comparison result that no arc is occurring in the plasma cavity, the PID controller is caused to maintain operation in a normal control state; The normal control state is maintaining a current operating state of the control module; continuing the arc detection sampling to obtain a reflection coefficient within the plasma cavity; Recording the average reflection coefficient under the current normal operating conditions; recording operating parameters for said control module; 2. The method for suppressing an arc in a plasma cavity according to claim 1, further comprising: recording operation variable parameters of the unit device at the output end, and setting a currently normally operating time node as a restoration node to continuously update the recorded operation variable parameters.

9. The process of instructing the state machine to lock the last operating parameters corresponding to the restoration node of the high frequency power system includes:

9. The method for suppressing an arc in a plasma cavity according to claim 8, further comprising: instructing the control module to lock the last average reflection coefficient under normal operating conditions by a state machine; instructing the control module to lock operating parameters; and instructing the output terminal to lock operating variable parameters of each unit device.

10. The step of obtaining a reflection coefficient within the plasma cavity by arc detection sampling includes: Employing periodic, fixed point sampling to obtain the instantaneous reflection coefficient; and calculating the average reflection coefficient based on all currently sampled instantaneous reflection coefficients, wherein each sampling, average calculation and threshold comparison are synchronous multi-threaded processes in a single time interval.

11. a detection sampling module for acquiring reflection coefficients within the plasma cavity by arc detection sampling, the reflection coefficients including an instantaneous reflection coefficient and an average reflection coefficient; a coefficient comparison module for comparing an absolute value of the difference between the instantaneous reflection coefficient and the average reflection coefficient with a predetermined reflection coefficient threshold; an arc-extinguishing module for instructing, via a state machine, to lock a last operating parameter corresponding to a restoration node of a high frequency power system, to suspend the arc detection sampling, and to shut off the power output of an output end coupled to the plasma cavity via a control module of a PID controller when it is determined based on a result of the comparison that an arc has occurred in the plasma cavity; and a power recovery module for instructing a control module of the PID controller to restore power output at the output and to restore the arc detection sampling based on the operating parameters after the arc in the plasma cavity is removed. Arc suppression device in the plasma cavity.

12. a high frequency power source, a PID controller, and a plasma cavity, the high frequency power source being electrically connected to the plasma cavity via the PID controller; The PID controller is obtaining reflection coefficients within the plasma cavity by arc detection sampling, the reflection coefficients including an instantaneous reflection coefficient and an average reflection coefficient; comparing an absolute value of the difference between the instantaneous reflection coefficient and the average reflection coefficient with a predetermined reflection coefficient threshold; if it is determined based on the comparison result that an arc has occurred in the plasma cavity, locking a last operating parameter corresponding to a restoration node of a high frequency power system, pausing the arc detection sampling, and cutting off the power output of an output end coupled to the plasma cavity; and after the arc in the plasma cavity is removed, restoring the power output at the output end and restoring the arc detection sampling based on the operating parameters. High frequency power supply system.

13. A computer-readable storage medium having a computer program stored thereon, When the computer program is executed by a processor, the steps of the method for suppressing an arc in a plasma cavity according to any one of claims 1 to 10 are realized. A computer-readable storage medium.

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