Plasma chamber arc suppression method, device and radio frequency power supply system

Abstract

The present application relates to a plasma chamber arc suppression method, device and radio frequency power supply system. The method comprises: obtaining the reflection coefficient in the plasma chamber through arc detection sampling; the reflection coefficient comprises 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 set reflection coefficient threshold; if it is determined that an arc is generated in the plasma chamber according to the comparison result, freezing the working parameters of the last corresponding restoration node of the radio frequency power supply system through a state machine instruction, suspending arc detection sampling and cutting off the power output of the output end of the plasma chamber through a control module of a PID controller; after the arc in the plasma chamber disappears, instructing the control module of the PID controller to restore the power output of the output end and restore arc detection sampling according to the working parameters. High-precision arc suppression processing in the chamber is achieved.

Description

Technical Field

[0001] The present application relates to the field of radio frequency system measurement and control technology, and in particular to a plasma chamber arc suppression method, device and radio frequency power supply system. Background Art

[0002] With the development of RF power supply technology, the application field of this technology has also been developed, expanding from the previous vacuum field to other fields, such as semiconductors and then beauty. The commonly said RF power supply system generally includes an RF power supply and a plasma chamber. The RF power supply is a supporting power supply for the plasma chamber, and is mostly used in equipment such as RF sputtering, PECVD chemical vapor deposition, and reactive ion etching. In practical applications, the generation of arcs in the plasma chamber will lead to a decrease in product yield, and will further lead to electromagnetic interference (EMI) problems. At present, for the generation of arcs in the plasma chamber, the traditional suppression technology is mainly based on the judgment method of detecting the instantaneous rate of change of voltage and current, while the arc extinguishing technology is to extinguish the arc through hardware equipment, and suppress the arc by designing an arc suppressor. However, in the implementation process, the inventor found that there is at least a technical problem of low arc suppression accuracy in the traditional technology. Summary of the invention

[0003] Based on this, it is necessary to provide a plasma chamber arc suppression method, a plasma chamber arc suppression device, a radio frequency power supply system and a computer-readable storage medium that can significantly improve the accuracy of arc suppression in the chamber in order to address the above technical problems.

[0004] In order to achieve the above objectives, this application provides the following technical solutions:

[0005] In one aspect, a method for suppressing an arc in a plasma chamber is provided, the method comprising:

[0006] The reflection coefficient in the plasma chamber is obtained by arc detection sampling; the reflection coefficient includes an instantaneous reflection coefficient and an average reflection coefficient;

[0007] The absolute value of the difference between the instantaneous reflection coefficient and the average reflection coefficient is compared with a set reflection coefficient threshold;

[0008] If it is determined according to the comparison result that an arc is generated in the plasma chamber, the state machine is used to instruct the freezing of the working parameters of the last corresponding restoration node of the RF power supply system, the arc detection sampling is suspended, and the power output of the output end connected to the plasma chamber is cut off through the control module of the PID controller;

[0009] After the arc in the plasma chamber disappears, the control module of the PID controller is instructed to restore the power output at the output end and resume arc detection sampling according to the working parameters.

[0010] In one embodiment, the process of determining whether an arc is generated in the plasma chamber according to the comparison result includes:

[0011] According to the situation that the absolute value of the difference is less than the set reflection coefficient threshold value and satisfies the set analysis and judgment conditions, it is determined whether an arc is generated in the plasma chamber or not.

[0012] In one embodiment, setting the analysis and judgment conditions includes:

[0013] If the absolute value of the difference is less than the set reflection coefficient threshold value for N consecutive times, it is determined that no arc is generated in the plasma chamber; N is a positive integer not less than 2.

[0014] In one embodiment, setting the analysis and judgment conditions includes:

[0015] If the absolute value of the difference is greater than the set reflection coefficient threshold value M times and is discontinuous within the set time period, it is determined that no arc is generated in the plasma chamber; M is a positive integer not less than 1.

[0016] In one embodiment, setting the analysis and judgment conditions includes:

[0017] If the absolute value of the difference is greater than the set reflection coefficient threshold value for 1 time, it is determined that an arc is generated in the plasma chamber.

[0018] In one embodiment, setting the analysis and judgment conditions includes:

[0019] If the absolute value of the difference is greater than the set reflection coefficient threshold value N times in a row, it is determined that an arc is generated in the plasma chamber; N is a positive integer not less than 2.

[0020] In one of the embodiments, the detection time period of the arc detection sampling includes a plurality of detection time periods from small to large, and the reflection coefficient threshold is set to be a coefficient threshold set manually or a coefficient threshold set adaptively by the system;

[0021] The above method further comprises the steps of:

[0022] Starting from the minimum detection time period, if the frequency of arc generation in the plasma chamber is less than the set frequency threshold, the detection time is extended to the next larger detection time period;

[0023] Otherwise, the detection time is kept unchanged, and the coefficient threshold of the system adaptive setting is adaptively increased by multiple growth or fixed value growth.

[0024] In one embodiment, the method further comprises the steps of:

[0025] If it is determined according to the comparison result that no arc is generated in the plasma chamber, the PID controller is maintained to work in a general control state;

[0026] Among them, the general control status includes:

[0027] Maintain the current working status of the control module;

[0028] Continuously perform arc detection sampling to obtain the reflection coefficient in the plasma chamber;

[0029] Record the average reflection coefficient under the current normal working condition;

[0030] Record the operating parameters of the control module;

[0031] The operating variable parameters of the unit devices at the output end are recorded, and the time node of the current normal operation is set as the restoration node and continuously updated.

[0032] In one embodiment, the process of freezing the working parameters of the last corresponding restoration node of the radio frequency power system through the state machine instruction includes:

[0033] The state machine instructs freezing of the last average reflection coefficient in the normal working state, instructs the control module to freeze the operating parameters, and instructs the output end to freeze the operating variable parameters of each unit device.

[0034] In one embodiment, the step of obtaining the reflection coefficient in the plasma chamber by arc detection sampling includes:

[0035] The instantaneous reflection coefficient is obtained by using the method of fixed-time fixed-point sampling;

[0036] The average reflection coefficient is calculated using all instantaneous reflection coefficients obtained by the current sampling; wherein each sampling, average calculation and threshold comparison are all processed by synchronous multi-threading in a single time interval.

[0037] In another aspect, a plasma chamber arc suppression device is provided, the device comprising:

[0038] A detection sampling module is used to obtain the reflection coefficient in the plasma chamber through arc detection sampling; the reflection coefficient includes an instantaneous reflection coefficient and an average reflection coefficient;

[0039] A coefficient comparison module, used for comparing the absolute value of the difference between the instantaneous reflection coefficient and the average reflection coefficient with a set reflection coefficient threshold;

[0040] The arc elimination module is used to freeze the working parameters of the last corresponding restoration node of the RF power supply system through the state machine instruction, suspend arc detection sampling, and cut off the power output of the output end connected to the plasma chamber through the control module of the PID controller when it is determined that an arc is generated in the plasma chamber according to the comparison result;

[0041] The output recovery module is used to instruct 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 working parameters after the arc in the plasma chamber disappears.

[0042] In yet another aspect, a radio frequency power supply system is provided, comprising a radio frequency power supply, a PID controller and a plasma chamber, wherein the radio frequency power supply is electrically connected to the plasma chamber via the PID controller;

[0043] The PID controller is used to implement the following arc suppression processing steps:

[0044] The reflection coefficient in the plasma chamber is obtained by arc detection sampling; the reflection coefficient includes an instantaneous reflection coefficient and an average reflection coefficient;

[0045] The absolute value of the difference between the instantaneous reflection coefficient and the average reflection coefficient is compared with a set reflection coefficient threshold;

[0046] If it is determined according to the comparison result that an arc is generated in the plasma chamber, the working parameters of the last corresponding restoration node of the RF power supply system are frozen, arc detection sampling is suspended, and the power output of the output end connected to the plasma chamber is cut off;

[0047] After the arc in the plasma chamber disappears, the power output at the output end is restored according to the working parameters and the arc detection sampling is restored.

[0048] On the other hand, a computer-readable storage medium is provided, on which a computer program is stored, and when the computer program is executed by a processor, the steps of any one of the above-mentioned plasma chamber arc suppression methods are implemented.

[0049] One of the above technical solutions has the following advantages and beneficial effects:

[0050] The above-mentioned plasma chamber arc suppression method, device and radio frequency power supply system obtain the instantaneous and average reflection coefficients in the plasma chamber through arc detection sampling, and then compare them with the set reflection coefficient threshold value to accurately determine whether an arc is generated in the plasma chamber. If it is determined that an arc is generated in the plasma chamber, the state machine will instruct the freezing of the working parameters of the last corresponding restoration node of the radio frequency power supply system, suspend arc detection sampling, and cut off the power output of the output end connected to the plasma chamber through the control module of the PID controller, that is, suspend the power output of the radio frequency power supply to the plasma chamber. After the arc in the plasma chamber disappears, the control module of the PID controller is instructed to resume the power output of the output end and resume arc detection sampling according to the working parameters, that is, resume the power output of the radio frequency power supply to the plasma chamber, thereby achieving high-precision suppression of the arc in the plasma chamber.

[0051] Compared with the traditional method, the above scheme greatly improves the accuracy of judging whether an arc has occurred through the comparison mechanism of the reflection coefficient mean (also called gamma mean) and the critical value. When determining that an arc has occurred, the state machine instructs the freezing system to freeze the working parameters of the last corresponding restoration node, suspend arc detection and suspend power output, so that after the arc disappears in the cavity, the power output can be accurately and quickly restored according to the frozen working parameters, achieving high-precision arc suppression processing in the cavity, and the arc suppression cost is lower, the efficiency is higher, and the adaptability is stronger. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the conventional technology, the drawings required for use in the embodiments or the conventional technology descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0053] Figure 1 A schematic environmental diagram of a plasma chamber arc suppression method in one embodiment;

[0054] Figure 2 is a schematic diagram of instantaneous value sampling in an embodiment;

[0055] Figure 3 A schematic diagram of the ARC inhibition stage in one embodiment;

[0056] Figure 4 A schematic diagram of a process flow of ARC monitoring and inhibition treatment in one embodiment;

[0057] Figure 5 is a block diagram of the module structure of a plasma chamber arc suppression device in one embodiment;

[0058] Figure 6 is a schematic diagram of the structural framework of a radio frequency power supply system in an embodiment;

[0059] Figure 7 FIG. 4 is a schematic diagram of the structure of an ARC processing module in one embodiment. DETAILED DESCRIPTION

[0060] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0061] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0062] It should be noted that the reference to "embodiment" in this document means that the specific features, structures or characteristics described in conjunction with the embodiment may be included in at least one embodiment of the present invention. The presentation of the phrase at various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments.

[0063] Those skilled in the art will appreciate that the embodiments described herein may be combined with other embodiments. The term "and / or" used in the present specification and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0064] In practical research, the inventors found that judging whether an arc phenomenon occurs only by detecting the rate of change of current and voltage may lead to misjudgment, thus affecting the normal operation of the system. Although the use of a special arc extinguishing device can effectively suppress the arc phenomenon, it increases the complexity of the system and the manufacturing cost. In the use scenario where only a small arc is generated, the necessity of the arc extinguishing device is not high. In addition, the arc extinguishing device needs to be designed for specific scenarios, and there are many types of arcs in the plasma chamber, and a single arc extinguishing device is difficult to be effective. Therefore, the present application proposes a new plasma chamber arc suppression method to achieve high-precision arc suppression in the cavity, in order to solve the technical problem that the arc suppression accuracy is at least low in the traditional technology.

[0065] The following will describe the implementation of the present invention in detail with reference to the accompanying drawings in the embodiment diagram of the present invention.

[0066] In one embodiment, Figure 1 As shown, a plasma chamber arc suppression method is provided, which can be applied to various types of radio frequency power supply systems. The method may include the following steps S12 to S18:

[0067] S12, obtaining the reflection coefficient in the plasma cavity through arc detection sampling; the reflection coefficient includes an instantaneous reflection coefficient and an average reflection coefficient.

[0068] It can be understood that arc detection sampling refers to a detection method that uses the existing sensor system of the system or an external sensor device to sample the measurement information of the plasma chamber so as to calculate the reflection coefficient (also referred to as gamma value in this article) in the plasma chamber. The sampled measurement information can be at least one or a combination of voltage value, current value, power value, cavity impedance value and power supply impedance value, as long as the reflection coefficient in the plasma chamber can be accurately measured. The instantaneous reflection coefficient refers to the real-time reflection coefficient in the plasma chamber obtained by sampling at the current moment, and the average reflection coefficient can refer to the average coefficient value calculated using the reflection coefficients obtained by all samplings up to the current moment.

[0069] Specifically, during the operation of the RF power supply system, arc detection sampling is performed on the system (mainly the relevant electrical parameters of the plasma chamber therein) to obtain the instantaneous reflection coefficient in the plasma chamber and calculate the corresponding average reflection coefficient.

[0070] S14, comparing the absolute value of the difference between the instantaneous reflection coefficient and the average reflection coefficient with a set reflection coefficient threshold.

[0071] It can be understood that for the convenience of description, the instantaneous reflection coefficient can be recorded as Γ cur , the average reflection coefficient is denoted as Γ aver , the above comparison process can be described as judging: |Γ cur –Γ aver |<Γ th If it is true, it means that the system is currently working normally and no arc is generated in the cavity. If it is not true, it means that the system is currently working abnormally and an arc is generated in the cavity.

[0072] The above-mentioned process of arc detection sampling, gamma mean calculation and comparison processing is used to accurately determine whether an arc is generated in the cavity, which can also be called ARC (arc) monitoring.

[0073] S16, if it is determined according to the comparison result that an arc is generated in the plasma chamber, the state machine is instructed to freeze the working parameters of the last corresponding restoration node of the RF power supply system, suspend arc detection sampling, and cut off the power output of the output end connected to the plasma chamber through the control module of the PID controller.

[0074] It can be understood that in the system, the state machine is a state control unit that instructs each module of the system to freeze and / or unfreeze the working parameters. During the operation of the system, the PID controller can include a general control state and a shutdown control state. The PID controller samples the instantaneous value of gamma to calculate its mean value and compares it with |Γ cur –Γ aver |<Γ thA comparison is made to obtain the instantaneous gamma value and the comparison result. When it is determined that no arc is generated, it is in the general control state. In this state, the PID controller maintains the current operation of its control module and continues to detect the gamma value. At the same time, it records the various working parameters of the normal operation of the system at the current time node. This time node can be identified as a restoration node, and the data of this restoration node will be continuously updated under the general control state.

[0075] When it is determined that an arc is generated in the plasma chamber, the PID controller switches to the shutdown control state. In this state, on the one hand, the state machine will also switch the operating state, instructing each module to freeze the working parameters of the last corresponding restoration node, and suspend arc detection sampling (ARC monitoring) for a period of 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 chamber); on the other hand, the control module of the PID controller is still in the operating state, disconnecting the power output of the output end of the plasma chamber to cut off the RF power output of the RF power supply to the plasma chamber. After the power output is disconnected, the plasma chamber will experience a potential drop, a period of stillness (zero potential time), and a potential re-increasing time (potential rise time) after the power is restored.

[0076] S18, after the arc in the plasma chamber disappears, the control module of the PID controller is instructed to restore the power output at the output end and restore the arc detection sampling according to the working parameters.

[0077] It can be understood that after the control module of the PID controller cuts off the power output of the output end of the plasma chamber, the potential of the plasma chamber drops and remains at zero potential for a set time to eliminate the arc generated in the chamber. After the static set time (the length of time can be set according to the shortest time of arc elimination / arc extinguishing time statistical law in actual application), the arc is eliminated. At this time, the state machine can switch the operating state to instruct each module to restore the normal working state according to the working parameters of the restored node that was last frozen before the arc extinguishing. The control module of the PID controller reconnects the power output of the plasma chamber, and the PID controller re-enables ARC monitoring, so as to enter the next round of arc monitoring and suppression work process. It can be understood by those skilled in the art that if the arc in the chamber is still detected after the work is resumed, the above actions can be repeated to suppress the arc. Optionally, the zero potential time can be extended to achieve a better arc extinguishing effect.

[0078] In the above-mentioned plasma chamber arc suppression method, the instantaneous and average reflection coefficients in the plasma chamber are obtained through arc detection sampling, and then compared with the set reflection coefficient threshold value to accurately determine whether an arc is generated in the plasma chamber. If it is determined that an arc is generated in the plasma chamber, the state machine will instruct to freeze the working parameters of the last corresponding restoration node of the RF power supply system, suspend arc detection sampling, and cut off the power output of the output end connected to the plasma chamber through the control module of the PID controller, that is, suspend the power output of the RF power supply to the plasma chamber. After the arc in the plasma chamber disappears, the control module of the PID controller is instructed to restore the power output of the output end and restore arc detection sampling according to the working parameters, that is, restore the power output of the RF power supply to the plasma chamber, thereby achieving high-precision suppression of the arc in the plasma chamber.

[0079] Compared with the traditional method, the above scheme greatly improves the accuracy of judging whether an arc has occurred through the comparison mechanism of the reflection coefficient mean (also called gamma mean) and the critical value. When determining that an arc has occurred, the state machine instructs the freezing system to freeze the working parameters of the last corresponding restoration node, suspend arc detection and suspend power output, so that after the arc disappears in the cavity, the power output can be accurately and quickly restored according to the frozen working parameters, achieving high-precision arc suppression processing in the cavity, and the arc suppression cost is lower, the efficiency is higher, and the adaptability is stronger.

[0080] In one embodiment, the method for judging whether the arc in the plasma chamber has disappeared may be, but is not limited to: by performing energy detection in the chamber, judging whether the residual energy in the chamber is zero or lower than the set energy threshold to determine whether the arc has disappeared (if the residual energy in the chamber is zero or lower than the set energy threshold, it can be determined that the arc has disappeared, otherwise it has not disappeared); or by cutting off the power output and waiting for a set time to determine that the arc in the chamber has disappeared; or by manually performing visual observation to judge whether the arc in the chamber has disappeared (if it is observed that there is no arc in the chamber, it is determined that the arc has disappeared, otherwise it has not disappeared). Other judgment methods are all acceptable as long as they can accurately judge whether the arc in the chamber has disappeared. By judging the state of the arc in the chamber in the above manner, the state machine can be promptly and accurately instructed to switch the working state, and each module can be instructed to restore the working state before freezing, reducing the power cut-off time, thereby improving the overall arc suppression processing efficiency.

[0081] In one embodiment, the above step S12 may specifically include the following processing steps:

[0082] The instantaneous reflection coefficient is obtained by using the method of fixed-time fixed-point sampling;

[0083] The average reflection coefficient is calculated using all instantaneous reflection coefficients obtained by the current sampling; wherein each sampling, average calculation and threshold comparison are all processed by synchronous multi-threading in a single time interval.

[0084] Specifically, the detection sampling of the instantaneous reflection coefficient adopts the method of fixed-time fixed-point sampling, and all the sampled values ​​are available values, which are used to calculate the gamma mean. In addition, for each sampling, coefficient and mean calculation, and threshold comparison process, in this embodiment, the PID controller adopts single time interval synchronous multi-threaded processing, which can achieve the same purpose in multiple sites synchronously, such as Figure 2 As shown, the reliability of intracavity reflection detection and arc judgment can be further improved.

[0085] In one embodiment, in the above step S16, the process of determining whether an arc is generated in the plasma chamber according to the comparison result may include the following judgment:

[0086] According to the situation that the absolute value of the difference is less than the set reflection coefficient threshold value and satisfies the set analysis and judgment conditions, it is determined whether an arc is generated in the plasma chamber or not.

[0087] It can be understood that in the above embodiment, by judging |Γ cur –Γ aver |<Γ th Whether it is established, and directly determine whether there is an arc in the cavity. In this embodiment, in order to further improve the accuracy of judging the arc generation, the judgment |Γ cur –Γ aver |<Γ th Whether the condition is established and whether the set analysis and judgment conditions are met can be used to more accurately determine whether an arc is generated in the cavity.

[0088] In one embodiment, optionally, setting the analysis and judgment conditions may include the following:

[0089] If the absolute value of the difference is less than the set reflection coefficient threshold value for N consecutive times, it is determined that no arc is generated in the plasma chamber; N is a positive integer not less than 2.

[0090] Specifically, if it is determined that continuous |Γ cur –Γ aver |<Γ th When this happens N times, it can be determined that no arc is generated in the plasma chamber.

[0091] In one embodiment, optionally, setting the analysis and judgment conditions may also include the following:

[0092] If the absolute value of the difference is greater than the set reflection coefficient threshold value M times and is discontinuous within the set time period, it is determined that no arc is generated in the plasma chamber; M is a positive integer not less than 1.

[0093] Specifically, if |Γ cur –Γ aver |>Γ th If the time period is within a certain period (i.e., a set period, the specific length of which can be determined based on monitoring experience in actual applications or statistics of historical monitoring data), the number of times M is less than or equal to 1 and is not continuous, it can be determined that no arc is generated in the current plasma chamber.

[0094] In one embodiment, optionally, setting the analysis and judgment conditions may also include the following:

[0095] If the absolute value of the difference is greater than the set reflection coefficient threshold value for 1 time, it is determined that an arc is generated in the plasma chamber.

[0096] Specifically, if |Γ cur –Γ aver |>Γ th If it is 1 time, it can be determined that an arc is generated in the plasma chamber.

[0097] In one embodiment, optionally, setting the analysis and judgment conditions may also include the following:

[0098] If the absolute value of the difference is greater than the set reflection coefficient threshold value N times in a row, it is determined that an arc is generated in the plasma chamber; N is a positive integer not less than 2.

[0099] Specifically, if |Γ cur –Γ aver |>Γ th If it happens for multiple times (including 2 times) in a row, it can be determined that an arc is generated in the plasma chamber.

[0100] It should be noted that the above-mentioned analysis and judgment conditions can be used in combination, as long as mutually exclusive conditions do not form a combination.

[0101] In one embodiment, the detection time period of the arc detection sampling includes multiple detection time periods from small to large. The reflection coefficient threshold is set to a coefficient threshold manually set or a coefficient threshold set by the system adaptively. The above-mentioned plasma chamber arc suppression method may also include the steps of:

[0102] Starting from the minimum detection time period, if the frequency of arc generation in the plasma chamber is less than the set frequency threshold, the detection time is extended to the next larger detection time period;

[0103] Otherwise, the detection time is kept unchanged, and the coefficient threshold of the system adaptive setting is adaptively increased by multiple growth or fixed value growth.

[0104] Specifically, the reflection coefficient threshold Γ is set th , can be set manually (such as based on work experience or historical monitoring data, etc.), or can be set by the system adaptively. When the system is set adaptively, an initial value Γ can be set first th , to introduce |Γ cur –Γ aver |<Γ th The initial comparison process, the initial value Γ th It can be set manually or by using Γ cur and Γ aver Dynamic data or historical data is calculated and generated.

[0105] In actual monitoring, several detection time periods can be set from small to large, such as but not limited to 8us, 16us, 32us, and so on. First, a minimum detection time period is set, such as 8us. Within the minimum detection time period, |Γ cur –Γ aver |<Γ th Evaluate the frequency of arc generation. If the frequency of arc generation is less than the preset frequency threshold, extend the detection time period to the next larger detection time period, such as 16us or 32us, and the coefficient threshold set by the system adaptively can remain unchanged. If the frequency of arc generation is higher than the preset frequency threshold within the minimum detection time period, increase Γ th Numerical value, such as using multiple growth or fixed value growth, or first obtaining |Γ cur –Γ aver |The dynamic maximum value is then increased by multiples or constant values ​​to be used as the adjusted Γ th .

[0106] Through the above steps, the coefficient threshold value of the system can be adjusted adaptively, thereby further improving the accuracy of judging the occurrence of arc.

[0107] In one embodiment, the plasma chamber arc suppression method further comprises the steps of:

[0108] If it is determined according to the comparison result that no arc is generated in the plasma chamber, the PID controller is maintained to work in the general control state. The general control state includes:

[0109] Maintain the current working status of the control module;

[0110] Continuously perform arc detection sampling to obtain the reflection coefficient in the plasma chamber;

[0111] Record the average reflection coefficient under the current normal working condition;

[0112] Record the operating parameters of the control module;

[0113] The operating variable parameters of the unit devices at the output end are recorded, and the time node of the current normal operation is set as the restoration node and continuously updated.

[0114] Specifically, in the general control state of the PID controller, the PID controller obtains the instantaneous value of gamma to calculate its mean value and compares it with |Γ cur –Γ aver |<Γ th When it is determined that no arc is generated, the general control state is maintained. At this time, the PID controller maintains the operation of the current control module and continuously monitors the gamma value, while recording the following operating parameters of the current time node: (a) the gamma mean value of normal operation; (b) the operating parameters of the PID controller's control module at the output end; (c) the operating variable parameters of the unit device of the output end operating the power output, and the time node is identified as the restoration node. The data of this restoration node will be continuously updated in the general control state.

[0115] In one embodiment, in the above step S16, the process of freezing the working parameters of the last corresponding restoration node of the RF power system through the state machine instruction may specifically include the following processing process:

[0116] The state machine instructs freezing of the last average reflection coefficient in the normal working state, instructs the control module to freeze the operating parameters, and instructs the output end to freeze the operating variable parameters of each unit device.

[0117] Specifically, when it is determined that an arc is generated, the PID controller switches to the shutdown control state, and its state machine also switches the operating state, instructing each module to freeze the working parameters of the last corresponding restoration node, such as instructing the module responsible for gamma mean calculation to freeze the gamma mean, instructing the control module of the PID controller to freeze its operating parameters, and instructing the output end connected to the plasma chamber to freeze the operating variable parameters of its unit device; at the same time, the state machine instructs the PID controller to suspend monitoring the gamma value in a time period X (including potential drop time + zero potential + potential rise).

[0118] like Figure 3 As shown in the figure, it is a schematic diagram of ARC suppression at each stage. The entire ARC occurrence process can be divided into seven stages, and the meaning and processing methods of each stage can be shown in Table 1. Through the above steps, the parameter freezing control mechanism provided by the state machine can ensure that the system can recover to the normal working state as quickly as possible after the arc is eliminated.

[0119] Table 1

[0120] stage significance Treatment A Power normal <![CDATA[Find the instantaneous reflection coefficient Γ cur and the average reflection coefficient Γ aver > B ARC occurs C ARC response time <![CDATA[|Γ cur -Γ aver |>Γ th When the power output is turned off, ARC monitoring is suspended]]> D Power falling edge E Pause power time This time can be set by the user F Power recovery delay This time can be set by the user G Delay end Re-enable ARC monitoring

[0121] like Figure 4 As shown in the figure, it is a schematic diagram of one of the ARC processing flow charts. The whole process can be divided into two parts: Gamma mean value calculation and comparison part and PID save suspension part. Through the above processing method, high-precision detection and suppression of ARC is achieved, and the system can be restored to work at the fastest speed after arc extinguishing with low arc extinguishing cost.

[0122] It should be understood that although Figure 1 and Figure 4 The steps in the flowchart are shown in sequence as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified in this document, there is no strict order restriction for the execution of these steps, and these steps can be executed in other orders. Moreover, Figure 1 and Figure 4 At least part of the steps may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily executed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be executed in turn or alternately with other steps or at least part of the sub-steps or stages of other steps.

[0123] In one embodiment, Figure 5 As shown, a plasma chamber arc suppression device 100 is provided, including a detection sampling module 11, a coefficient comparison module 13, an arc elimination module 15 and an output recovery module 17. Among them: the detection sampling module 11 is used to obtain the reflection coefficient in the plasma chamber through arc detection sampling; the reflection coefficient includes an instantaneous reflection coefficient and an average reflection coefficient. The coefficient comparison module 13 is used to compare the absolute value of the difference between the instantaneous reflection coefficient and the average reflection coefficient with the set reflection coefficient threshold. The arc elimination module 15 is used to freeze the working parameters of the last corresponding restoration node of the RF power supply system through a state machine instruction, suspend arc detection sampling, and cut off the power output of the output end connected to the plasma chamber through the control module of the PID controller when it is determined that an arc is generated in the plasma chamber according to the comparison result, and to restore the arc detection sampling. The output recovery module 17 is used to instruct 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 working parameters after the arc in the plasma chamber disappears.

[0124] The above-mentioned plasma chamber arc suppression device 100 obtains the instantaneous and average reflection coefficients in the plasma chamber through arc detection sampling, and then compares them with the set reflection coefficient threshold to accurately determine whether an arc is generated in the plasma chamber. If it is determined that an arc is generated in the plasma chamber, the state machine will instruct to freeze the working parameters of the last corresponding restoration node of the RF power supply system, suspend arc detection sampling, and cut off the power output of the output end connected to the plasma chamber through the control module of the PID controller, that is, suspend the power output of the RF power supply to the plasma chamber. After the arc in the plasma chamber disappears, the control module of the PID controller is instructed to resume the power output of the output end and resume arc detection sampling according to the working parameters, that is, resume the power output of the RF power supply to the plasma chamber, thereby achieving high-precision suppression of the arc in the plasma chamber.

[0125] Compared with the traditional method, the above scheme greatly improves the accuracy of judging whether an arc has occurred through the comparison mechanism of the reflection coefficient mean (also called gamma mean) and the critical value. When determining that an arc has occurred, the state machine instructs the freezing system to freeze the working parameters of the last corresponding restoration node, suspend arc detection and suspend power output, so that after the arc disappears in the cavity, the power output can be accurately and quickly restored according to the frozen working parameters, achieving high-precision arc suppression processing in the cavity, and the arc suppression cost is lower, the efficiency is higher, and the adaptability is stronger.

[0126] In one embodiment, the process of determining whether an arc is generated in the plasma chamber according to the comparison result includes:

[0127] According to the situation that the absolute value of the difference is less than the set reflection coefficient threshold value and satisfies the set analysis and judgment conditions, it is determined whether an arc is generated in the plasma chamber or not.

[0128] In one embodiment, setting the analysis and judgment conditions includes:

[0129] If the absolute value of the difference is less than the set reflection coefficient threshold value for N consecutive times, it is determined that no arc is generated in the plasma chamber; N is a positive integer not less than 2.

[0130] In one embodiment, setting the analysis and judgment conditions includes:

[0131] If the absolute value of the difference is greater than the set reflection coefficient threshold value M times and is discontinuous within the set time period, it is determined that no arc is generated in the plasma chamber; M is a positive integer not less than 1.

[0132] In one embodiment, setting the analysis and judgment conditions includes:

[0133] If the absolute value of the difference is greater than the set reflection coefficient threshold value for 1 time, it is determined that an arc is generated in the plasma chamber.

[0134] In one embodiment, setting the analysis and judgment conditions includes:

[0135] If the absolute value of the difference is greater than the set reflection coefficient threshold value N times in a row, it is determined that an arc is generated in the plasma chamber; N is a positive integer not less than 2.

[0136] In one embodiment, the detection time period of arc detection sampling includes a plurality of detection time periods from small to large, and the reflection coefficient threshold is set to be a coefficient threshold set manually or a coefficient threshold set adaptively by the system;

[0137] The above method further comprises the steps of:

[0138] Starting from the minimum detection time period, if the frequency of arc generation in the plasma chamber is less than the set frequency threshold, the detection time is extended to the next larger detection time period;

[0139] Otherwise, the detection time is kept unchanged, and the coefficient threshold of the system adaptive setting is adaptively increased by multiple growth or fixed value growth.

[0140] In one embodiment, the method further comprises the steps of:

[0141] If it is determined according to the comparison result that no arc is generated in the plasma chamber, the PID controller is maintained to work in a general control state;

[0142] Among them, the general control status includes:

[0143] Maintain the current working status of the control module;

[0144] Continuously perform arc detection sampling to obtain the reflection coefficient in the plasma chamber;

[0145] Record the average reflection coefficient under the current normal working condition;

[0146] Record the operating parameters of the control module;

[0147] The operating variable parameters of the unit devices at the output end are recorded, and the time node of the current normal operation is set as the restoration node and continuously updated.

[0148] In one embodiment, the process of freezing the working parameters of the last corresponding restoration node of the radio frequency power supply system through the state machine instruction includes:

[0149] The state machine instructs freezing of the last average reflection coefficient in the normal working state, instructs the control module to freeze the operating parameters, and instructs the output end to freeze the operating variable parameters of each unit device.

[0150] In one embodiment, the step of acquiring the reflection coefficient in the plasma chamber by arc detection sampling includes:

[0151] The instantaneous reflection coefficient is obtained by using the method of fixed-time fixed-point sampling;

[0152] The average reflection coefficient is calculated using all instantaneous reflection coefficients obtained by the current sampling; wherein each sampling, average calculation and threshold comparison are all processed by synchronous multi-threading in a single time interval.

[0153] For the specific definition of the plasma chamber arc suppression device 100, please refer to the definition of the plasma chamber arc suppression method above, which will not be repeated here. Each module in the above-mentioned plasma chamber arc suppression device 100 can be implemented in whole or in part by software, hardware and a combination thereof. The above-mentioned modules can be embedded in or independent of the PID controller or processor in the RF power supply system in the form of hardware, or can be stored in the memory of the RF power supply system in the form of software, so that the PID controller or processor can call and execute the operations corresponding to the above modules.

[0154] In one embodiment, Figure 6 As shown, a radio frequency power supply system 200 is provided, including a radio frequency power supply 22, a PID controller 24 and a plasma chamber 26. The radio frequency power supply 22 is electrically connected to the plasma chamber 26 through the PID controller 24. The PID controller 24 is used to implement the following arc suppression processing steps:

[0155] The reflection coefficient in the plasma chamber is obtained by arc detection sampling; the reflection coefficient includes an instantaneous reflection coefficient and an average reflection coefficient;

[0156] The absolute value of the difference between the instantaneous reflection coefficient and the average reflection coefficient is compared with a set reflection coefficient threshold;

[0157] If it is determined according to the comparison result that an arc is generated in the plasma chamber, the working parameters of the last corresponding restoration node of the RF power supply 22 system are frozen, arc detection sampling is suspended, and the power output of the output end connected to the plasma chamber is cut off;

[0158] After the arc in the plasma chamber disappears, the power output at the output end is restored according to the working parameters and the arc detection sampling is restored.

[0159] It can be understood that the specific definition of the functions implemented by the above-mentioned PID controller 24 can be referred to the corresponding definition of the plasma chamber arc suppression method in the above text, which will not be repeated here. The specific electrical connection relationship between the various components in the above-mentioned RF power supply system 200 and its mechanical structure can be understood by referring to the electrical and mechanical structure of the existing RF power supply system 22 in the art, and will not be repeated in this specification.

[0160] Figure 7FIG. 2 shows the structure of the ARC processing module divided according to the functions to be implemented. The PID controller 24 can be divided into a control module for controlling the output end of the plasma chamber 26 and a control module for controlling the output end of the plasma chamber 26. Figure 7 The ARC processing module shown in the figure includes an average calculation unit, a comparison unit, an ARC detection unit and a state machine. The average calculation unit can be used to calculate the instantaneous reflection coefficient and the corresponding average reflection coefficient from the measurement information of the real-time detection sampling. The comparison unit can be used to perform |Γ cur –Γ aver |with Γ th The ARC detection unit can be used to determine whether an arc is generated in the cavity according to the comparison result. The state machine can be used to implement the corresponding indication control function shown in the above embodiment.

[0161] Those skilled in the art will understand that Figure 6 and Figure 7 It is only a block diagram of some product entities and functional structures related to the present application scheme, and does not constitute a detailed limitation of the RF power supply system used in the present application scheme. The specific RF power supply system may include more or fewer components than those shown in the above figure, or combine certain components, or have a different arrangement of components, which can be determined according to the actual type of RF power supply system.

[0162] The above-mentioned RF power supply system 200 obtains the instantaneous and average reflection coefficients in the plasma chamber through arc detection sampling, and then compares them with the set reflection coefficient threshold to accurately determine whether an arc is generated in the plasma chamber. If it is determined that an arc is generated in the plasma chamber, the state machine will instruct the freezing of the working parameters of the last corresponding restoration node of the RF power supply system, suspend the arc detection sampling, and cut off the power output of the output end connected to the plasma chamber through the control module of the PID controller 24, that is, the power output of the RF power supply to the plasma chamber 26 is suspended. After the arc in the plasma chamber disappears, the control module of the PID controller 24 is instructed to restore the power output of the output end and restore the arc detection sampling according to the working parameters, that is, the power output of the RF power supply to the plasma chamber 26 is restored, thereby achieving high-precision suppression of the arc in the plasma chamber.

[0163] Compared with the traditional method, the above scheme greatly improves the accuracy of judging whether an arc has occurred through the comparison mechanism of the reflection coefficient mean (also called gamma mean) and the critical value. When determining that an arc has occurred, the state machine instructs the freezing system to freeze the working parameters of the last corresponding restoration node, suspend arc detection and suspend power output, so that after the arc disappears in the cavity, the power output can be accurately and quickly restored according to the frozen working parameters, achieving high-precision arc suppression processing in the cavity, and the arc suppression cost is lower, the efficiency is higher, and the adaptability is stronger.

[0164] In one embodiment, a computer-readable storage medium is also provided, on which a computer program is stored. When the computer program is executed by a processor, the following processing steps are implemented: obtaining a reflection coefficient in a plasma chamber through arc detection sampling; 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 set reflection coefficient threshold; if it is determined that an arc is generated in the plasma chamber according to the comparison result, freezing the working parameters of the last corresponding restoration node of the RF power supply system through a state machine instruction, pausing arc detection sampling, and cutting off the power output of the output end connected to the plasma chamber through a control module of a PID controller; after the arc in the plasma chamber disappears, instructing the control module of the PID controller to restore the power output of the output end and restore arc detection sampling according to the working parameters.

[0165] In one embodiment, when the computer program is executed by a processor, it can also implement the steps or sub-steps added in the above-mentioned plasma chamber arc suppression method embodiments.

[0166] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiments can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in the present application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. As an illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0167] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0168] The above embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A plasma chamber arc suppression method, characterized in that: The following steps are involved: The reflection coefficient in the plasma cavity is obtained by arc detection sampling; the reflection coefficient includes an instantaneous reflection coefficient and an average reflection coefficient; the instantaneous reflection coefficient refers to the real-time reflection coefficient in the plasma cavity obtained by sampling at the current moment, and the average reflection coefficient refers to the average coefficient value calculated using the reflection coefficients obtained by all samplings up to the current moment; Compare the absolute value of the difference between the instantaneous reflection coefficient and the average reflection coefficient with a set reflection coefficient threshold; If it is determined according to the comparison result that an arc is generated in the plasma chamber, the state machine instructs to freeze the working parameters of the last corresponding restoration node of the RF power supply system, suspend the arc detection sampling, and cut off the power output of the output end connected to the plasma chamber through the control module of the PID controller; the duration of suspending the arc detection sampling is set according to the potential falling time, zero potential time, and potential rising time of the plasma chamber; the restoration node is the time node of the normal operation of the system; After the arc in the plasma chamber disappears, the control module of the PID controller is instructed to restore the power output of the output end and restore the arc detection sampling according to the working parameters.

2. The plasma chamber arc suppression method according to claim 1, characterized in that: The process of determining whether an arc is generated in the plasma chamber according to the comparison result includes: According to the situation that the absolute value of the difference is less than the set reflection coefficient threshold and satisfies the set analysis and judgment condition, it is determined whether an arc is generated in the plasma chamber or not.

3. The plasma chamber arc suppression method according to claim 2, characterized in that: The setting of analysis and judgment conditions includes: If the absolute value of the difference is smaller than the set reflection coefficient threshold value N times in a row, it is determined that no arc is generated in the plasma chamber; N is a positive integer not less than 2.

4. The plasma chamber arc suppression method according to claim 2 or 3, characterized in that: The setting of analysis and judgment conditions includes: If the absolute value of the difference is greater than the set reflection coefficient threshold M times and is discontinuous within a set time period, it is determined that no arc is generated in the plasma chamber; M is a positive integer not less than 1.

5. The plasma chamber arc suppression method according to claim 2, characterized in that: The setting of analysis and judgment conditions includes: If the absolute value of the difference is greater than the set reflection coefficient threshold by 1 time, it is determined that an arc is generated in the plasma chamber.

6. The plasma chamber arc suppression method according to claim 2, 3 or 5, characterized in that: The setting of analysis and judgment conditions includes: If the absolute value of the difference is greater than the set reflection coefficient threshold value N times in a row, it is determined that an arc is generated in the plasma chamber; N is a positive integer not less than 2.

7. The plasma chamber arc suppression method according to claim 1, characterized in that: The detection time period of the arc detection sampling includes a plurality of detection time periods from small to large, and the set reflection coefficient threshold is a coefficient threshold set manually or a coefficient threshold set adaptively by the system; The method further comprises the steps of: Starting from the minimum detection time period, if the frequency of arc generation in the plasma chamber is less than the set frequency threshold, the detection time is extended to the next larger detection time period; Otherwise, the detection time is kept unchanged, and the coefficient threshold of the system adaptive setting is adaptively increased by multiple growth or fixed value growth.

8. The plasma chamber arc suppression method according to claim 1, characterized in that: The method further comprises the steps of: If it is determined according to the comparison result that no arc is generated in the plasma chamber, the PID controller is maintained to operate in a general control state; The general control state includes: Maintaining the current working state of the control module; Continuously perform arc detection sampling to obtain the reflection coefficient in the plasma chamber; Record the average reflection coefficient under the current normal working condition; Recording operating parameters of the control module; The operating variable parameters of the unit device at the output end are recorded, and the time node of the current normal operation is set as the restoration node and continuously updated.

9. The plasma chamber arc suppression method according to claim 8, characterized in that: The process of freezing the working parameters of the last corresponding restored node of the RF power system through the state machine instruction includes: The state machine instructs freezing the last average reflection coefficient in the normal working state, instructs the control module to freeze the operating parameters, and instructs the output end to freeze the operating variable parameters of each unit device.

10. The plasma chamber arc suppression method according to claim 1, characterized in that: The step of obtaining the reflection coefficient in the plasma chamber by arc detection sampling comprises: The instantaneous reflection coefficient is obtained by adopting a fixed-time fixed-point sampling method; The average reflection coefficient is calculated using all instantaneous reflection coefficients obtained by current sampling; wherein each sampling, mean value calculation and threshold value comparison are all single time interval synchronous multi-threaded processing.

11. A plasma chamber arc suppression device, characterized in that: The device comprises: A detection sampling module, used for acquiring the reflection coefficient in the plasma chamber through arc detection sampling; the reflection coefficient includes an instantaneous reflection coefficient and an average reflection coefficient; A coefficient comparison module, used for comparing the absolute value of the difference between the instantaneous reflection coefficient and the average reflection coefficient with a set reflection coefficient threshold; An arc elimination module, for freezing the working parameters of the last corresponding restoration node of the radio frequency power supply system through a state machine instruction, suspending the arc detection sampling, and cutting off the power output of the output end connected to the plasma chamber through a control module of a PID controller when it is determined that an arc is generated in the plasma chamber according to the comparison result; The output recovery module is used to instruct 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 working parameters after the arc in the plasma chamber disappears.

12. A radio frequency power supply system, characterized in that: It includes a radio frequency power supply, a PID controller and a plasma chamber, wherein the radio frequency power supply is electrically connected to the plasma chamber through the PID controller; The PID controller is used to implement the following arc suppression processing steps: Acquiring a reflection coefficient in the plasma chamber by arc detection sampling; the reflection coefficient includes an instantaneous reflection coefficient and an average reflection coefficient; Compare the absolute value of the difference between the instantaneous reflection coefficient and the average reflection coefficient with a set reflection coefficient threshold; If it is determined according to the comparison result that an arc is generated in the plasma chamber, the working parameters of the last corresponding restoration node of the radio frequency power supply system are frozen, the arc detection sampling is suspended, and the power output of the output end connected to the plasma chamber is cut off; After the arc in the plasma chamber disappears, the power output of the output end is restored according to the working parameters and the arc detection sampling is restored.

13. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the plasma chamber arc suppression method according to any one of claims 1 to 10 are implemented.

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