WO2023222046A1 - Plasma chamber arc suppression method and apparatus, and radio frequency power supply system - Google Patents

Abstract

The present application relates to a plasma chamber arc suppression method and apparatus, and a radio frequency power supply system. The method comprises: acquiring reflection coefficients in a plasma chamber by means of arc detection sampling, the reflection coefficients comprising 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 produced in the plasma chamber according to a comparison result, instructing, by means of a state machine, to freeze the last working parameters corresponding to a recovery node of the radio frequency power supply system, to pause arc detection sampling, and to cut off power output of an output end connected to the plasma chamber by means of a control module of a PID controller; and after the electric arc in the plasma chamber disappears, instructing the control module of the PID controller to restore power output of the output end according to working parameters, and restoring electric arc detection sampling. High precision intrachamber arc suppression is implemented.

Description

Plasma cavity arc suppression method, device and radio frequency power supply system Technical field

This application relates to the technical field of radio frequency system measurement and control, and in particular to a plasma cavity arc suppression method, device and radio frequency power supply system.

Background technique

With the development of radio frequency power supply technology, the application fields of this technology have also developed, expanding from the previous vacuum field to other fields, such as semiconductors and then beauty. The often mentioned RF power supply system generally includes a 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 further lead to electromagnetic interference (EMI) problems. At present, for the generation of arc in the plasma chamber, the traditional suppression technology is mainly based on the detection of the instantaneous change rate of voltage and current, while the arc extinguishing technology extinguishes the arc through hardware equipment and suppresses the arc by designing an arc suppressor. However, during the implementation process, the inventor discovered that there is at least a technical problem of low arc suppression accuracy in the traditional technology.

Contents of the invention

Based on this, it is necessary to address the above technical problems and provide a plasma cavity arc suppression method, a plasma cavity arc suppression device, a radio frequency power supply system and a computer-readable storage medium that can greatly improve the accuracy of intra-cavity arc suppression.

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

On the one hand, a plasma cavity arc suppression method is provided, which method includes:

Obtain the reflection coefficient in the plasma cavity through arc detection sampling; the reflection coefficient includes instantaneous reflection coefficient and average reflection coefficient;

Compare the absolute value of the difference between the instantaneous reflection coefficient and the average reflection coefficient with the set reflection coefficient threshold;

If it is determined that an arc is generated in the plasma cavity based on the comparison results, the state machine is used to instruct the RF power supply system to freeze the working parameters of the last corresponding restoration node, pause arc detection sampling, and cut off the power to the output end of the docking plasma cavity through the control module of the PID controller. output;

After the arc in the plasma cavity disappears, the control module of the PID controller is instructed according to the working parameters. Restore power output at the output and resume arc detection sampling.

In one embodiment, the process of determining whether there is arc generation in the plasma cavity based on the comparison results includes:

According to the situation that the absolute value of the difference is less than the set reflection coefficient threshold and meets the set analysis and judgment conditions, it is determined whether there is arc generation or no arc generation in the plasma cavity.

In one embodiment, setting analysis and judgment conditions includes:

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

In one embodiment, setting 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 the set period, it is determined that no arc is generated in the plasma cavity; M is a positive integer not less than 1.

In one embodiment, setting analysis and judgment conditions includes:

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

In one embodiment, setting analysis and judgment conditions includes:

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

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

The above method also includes the steps:

Starting from the minimum detection time period, if the frequency of arc generation in the plasma cavity is less than the set frequency threshold, the detection time will be extended to the next larger detection time period;

Otherwise, the detection time remains unchanged, and the coefficient threshold set by the system is adaptively increased by a multiple increase or a fixed value increase.

In one embodiment, the above method further includes the steps:

If it is determined based on the comparison results that no arc is generated in the plasma cavity, the PID controller is maintained in the general control state;

Among them, the general control status includes:

Maintain the current working status of the control module;

Continuously conduct arc detection sampling to obtain the reflection coefficient in the plasma cavity;

Record the average reflection coefficient under current normal working conditions;

Record the operating parameters of the control module;

Record the operating variable parameters of the unit device at the output end, set the current normal working time node as the restoration node, and continuously update it.

In one embodiment, the process of freezing the radio frequency power supply system and finally corresponding to restoring the operating parameters of the node is instructed through a state machine, including:

The state machine instructs the 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 terminal to freeze the operating variable parameters of each unit device.

In one embodiment, the step of obtaining the reflection coefficient in the plasma cavity through arc detection sampling includes:

Use timed and fixed-point sampling to obtain the instantaneous reflection coefficient;

The average reflection coefficient is calculated using all the instantaneous reflection coefficients obtained by the current sampling; among them, each sampling, mean calculation and threshold comparison are all single-time interval synchronous multi-thread processing.

On the other hand, a plasma cavity arc suppression device is provided, which includes:

The detection sampling module is used to obtain the reflection coefficient in the plasma cavity through arc detection sampling; the reflection coefficient includes the instantaneous reflection coefficient and the average reflection coefficient;

The coefficient comparison module 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 is used to instruct the freezing of the radio frequency power supply system through the state machine and finally the working parameters of the corresponding restoration node, suspend arc detection sampling, and cut off the docking through the control module of the PID controller when it is determined that an arc is generated in the plasma cavity based on the comparison results. power output at the output of the plasma chamber;

The output recovery module is used to instruct the control module of the PID controller to restore the power output at the output end and resume arc detection sampling according to the working parameters after the arc in the plasma cavity disappears.

In another aspect, a radio frequency power supply system is provided, including a radio frequency power supply, a PID controller and a plasma chamber, and 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:

Obtain the reflection coefficient in the plasma cavity through arc detection sampling; the reflection coefficient includes instantaneous reflection coefficient and average reflection coefficient;

Compare the absolute value of the difference between the instantaneous reflection coefficient and the average reflection coefficient with the set reflection coefficient threshold;

If it is determined that an arc is generated in the plasma cavity based on the comparison results, the operating parameters of the last corresponding reduction node of the RF power supply system will be frozen, arc detection sampling will be suspended, and the power output of the output end connected to the plasma cavity will be cut off;

After the arc in the plasma cavity disappears, the power output at the output end is restored according to the working parameters and arc detection sampling is resumed.

In yet another aspect, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps of any of the above plasma cavity arc suppression methods are implemented.

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

The above-mentioned plasma cavity arc suppression method, device and radio frequency power supply system obtain the instantaneous and average reflection coefficient in the plasma cavity through arc detection sampling, and then compare it with the set reflection coefficient threshold to accurately determine whether there is an arc in the plasma cavity. If determined If an arc occurs in the plasma cavity, the state machine will instruct the RF power supply system to freeze the working parameters of the final corresponding restoration node, suspend arc detection sampling, and cut off the power output of the output end of the docking plasma cavity through the control module of the PID controller, that is, The power output of the RF power supply to the plasma chamber is suspended. After the arc in the plasma chamber disappears, the control module of the PID controller is instructed according to the working parameters to resume the power output at the output end and resume arc detection sampling, that is, the RF power supply is restored to the plasma chamber. The power output of the chamber achieves high-precision suppression of arcs in the plasma chamber.

Compared with the traditional method, the above scheme greatly improves the accuracy of judging whether an arc is generated through the comparison mechanism between the average reflection coefficient (also called gamma average) and the critical value. When the arc generation is determined, the state machine is used to instruct the freezing system to work parameters corresponding to the final restoration node, suspend arc detection and suspend power output. Therefore, after the arc disappears in the cavity, power output can be accurately and quickly restored according to the frozen working parameters, achieving high Precise intra-cavity arc suppression processing, with lower arc suppression cost, higher efficiency and stronger adaptability.

Description of the drawings

In order to more clearly explain the technical solutions in the embodiments of the present application or the traditional technology, the drawings needed to be used in the description of the embodiments or the traditional technology will be briefly introduced below. Obviously, the drawings in the following description are only for the purpose of explaining the embodiments or the technical solutions of the traditional technology. For some embodiments of the application, those of ordinary skill in the art can also obtain other drawings based on these drawings without exerting creative efforts.

Figure 1 is a schematic process environment diagram of a plasma cavity arc suppression method in one embodiment;

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

Figure 3 is a schematic diagram of the ARC inhibition stage in one embodiment;

Figure 4 is a schematic flow chart of ARC monitoring and suppression processing in one embodiment;

Figure 5 is a module structural block diagram of a plasma cavity arc suppression device in one embodiment;

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

Figure 7 is a schematic structural diagram of an ARC processing module in an embodiment.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present application more clear, the present application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present application and are not used to limit the present application.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which this application belongs. The terminology used herein in the description of the application is for the purpose of describing specific embodiments only and is not intended to limit the application.

It should be noted that reference to "embodiments" herein means that specific features, structures or characteristics described in connection with the embodiments may be included in at least one embodiment of the present invention. The appearances of this phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments.

Those skilled in the art will appreciate that the embodiments described herein may be combined with other embodiments. As used in this specification 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.

In practical research, the inventor found that only detecting the current and voltage change rate to determine whether an arc phenomenon occurs may lead to misjudgment, thereby affecting the normal operation of the system. Although the use of a special arc extinguishing device can effectively suppress arc phenomena, it increases system complexity and manufacturing costs. In usage scenarios where only small arcs are generated, the arc extinguishing device is not necessary. In addition, arc extinguishing devices need to be designed for specific scenarios, and there are many types of arcs in the plasma cavity, making it difficult for a single arc extinguishing device to be effective. Therefore, this application proposes a new plasma cavity arc suppression method that can achieve high-precision intra-cavity arc suppression in order to address the technical problem of low arc suppression accuracy at least in traditional technology.

The embodiments of the present invention will be described in detail below with reference to the accompanying drawings of the embodiments of the present invention.

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

S12, obtain the reflection coefficient in the plasma cavity through arc detection sampling; the reflection coefficient includes the instantaneous reflection coefficient and the average reflection coefficient.

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

Specifically, during the operation of the radio frequency power supply system, arc detection and sampling are performed on the system (mainly the relevant electrical parameters of the plasma chamber) to obtain the instantaneous reflection coefficient in the plasma chamber and calculate the corresponding average reflection coefficient.

S14: Compare the absolute value of the difference between the instantaneous reflection coefficient and the average reflection coefficient with the set reflection coefficient threshold.

It can be understood that for the convenience of description, the instantaneous reflection coefficient can be recorded as Γ _cur and the average reflection coefficient as Γ _aver . The above comparison process can be described as a judgment: Is |Γ _cur – Γ _aver |<Γ _th true? If true, then It means that the system is currently working normally and there is no arc generated in the cavity. If it is not true, it means that the system is currently working abnormally and there is arc generated in the cavity.

The above-mentioned part of arc detection sampling, gamma average calculation and comparison processing is used to accurately determine whether there is an arc in the cavity, which can also be called ARC (arc) monitoring.

S16, if it is determined that an arc is generated in the plasma cavity based on the comparison results, 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 output of the docking plasma cavity is cut off through the control module of the PID controller. terminal power output.

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 working parameters. During the system operation, the PID controller can include general control state and shutdown control state. The PID controller samples and obtains the instantaneous value of gamma to calculate its average value, and compares it with |Γ _cur –Γ _aver |<Γ _th . When the instantaneous value of gamma and the comparison result are obtained and it is judged that no arc is generated, it is a general control state. This state The lower PID controller maintains the current operation of its control module and continues to detect The gamma value also records various working parameters of the system's normal operation 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 general control conditions.

When it is determined that an arc is generated in the plasma cavity, the PID controller switches to the shutdown control state. In this state, on the one hand, the state machine will also switch to the operating state, instructing each module to freeze the working parameters of the last corresponding reduction node and suspend arc detection. Sampling (ARC monitoring) for a period of time X (the length of this time Open the power output of the output end of the docking plasma cavity to cut off the RF power output of the RF power supply to the plasma chamber. After disconnecting the power output, the plasma chamber will experience a potential drop, a period of inactivity (zero potential time), and subsequent restoration of power. The subsequent potential re-raising time (potential rise time).

S18, after the arc in the plasma cavity disappears, instruct the control module of the PID controller to restore the power output at the output end and resume arc detection sampling according to the working parameters.

It can be understood that after the control module of the PID controller cuts off the power output of the output end connected to 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 setting time (the length of this time can be set according to the statistical rules of the minimum arc elimination time/arc extinguishing time in actual applications), the arc is eliminated. At this time, the operating state can be switched by the state machine to instruct each module to follow the arc extinguishing time. The working parameters of the last frozen reduction node return to normal working status, the control module of the PID controller reconnects the power output of the docking plasma chamber, and the PID controller re-enables ARC monitoring, thus entering the next round of arc monitoring and inhibit the work process. Those skilled in the art can understand that if arc generation in the cavity is still detected after resumption of work, the above actions can be repeated to suppress the arc, and optionally, the zero potential time can be extended to achieve better arc extinguishing effect.

In the above plasma cavity arc suppression method, the instantaneous and average reflection coefficients in the plasma cavity are obtained through arc detection sampling, and then compared with the set reflection coefficient threshold to accurately determine whether there is an arc in the plasma cavity. If it is determined that there is an arc in the plasma cavity, generated, then the state machine will be used to instruct the RF power supply system to freeze the working parameters of the last corresponding restoration node, suspend arc detection sampling, and cut off the power output of the output end of the docking plasma cavity through the control module of the PID controller, that is, suspend the RF power supply to the plasma After the arc in the plasma chamber disappears, the control module of the PID controller is instructed according to the working parameters to restore the power output at the output end and resume arc detection sampling, that is, restore the power output of the RF power supply to the plasma chamber. This achieves high-precision suppression of arcs in the plasma cavity.

Compared with the traditional method, the above scheme greatly improves the accuracy of judging whether an arc is generated through the comparison mechanism between the average reflection coefficient (also called gamma average) and the critical value. When the arc generation is determined, the state machine is used to instruct the freezing system to work parameters corresponding to the final restoration node, suspend arc detection and suspend power output. Therefore, after the arc disappears in the cavity, power output can be accurately and quickly restored according to the frozen working parameters, achieving high Precise intra-cavity arc suppression processing, with lower arc suppression cost, higher efficiency and stronger adaptability.

In one embodiment, the method of determining whether the arc in the plasma cavity has disappeared can be, but is not limited to: performing energy detection in the cavity and determining whether the residual energy in the cavity has returned to zero or is lower than a set energy threshold to determine whether the arc has disappeared. has disappeared (when the residual energy in the cavity returns to zero or is 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, it can be determined that the arc in the cavity has disappeared. disappear; or it can be judged by manual visual observation whether the arc in the cavity has disappeared (observation finds that there is no arc in the cavity, it is determined that the arc has disappeared, otherwise it has not disappeared). Other judgment methods are acceptable as long as it can accurately judge whether the arc in the cavity has disappeared. By judging the arc status in the cavity in the above way, the state machine can be timely and accurately instructed to switch to the working state, and each module can be instructed to restore the working state before freezing, thereby reducing the power cut-off time, thereby improving the overall arc suppression processing efficiency.

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

Use timed and fixed-point sampling to obtain the instantaneous reflection coefficient;

The average reflection coefficient is calculated using all the instantaneous reflection coefficients obtained by the current sampling; among them, each sampling, mean calculation and threshold comparison are all single-time interval synchronous multi-thread processing.

Specifically, the detection and sampling of instantaneous reflection coefficients adopts a timed and fixed-point sampling method. All sampled values are usable values and 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 uses single-time interval synchronous multi-thread processing, which can achieve the same purpose at multiple work sites simultaneously, as shown in Figure 2 display to further improve the reliability of intra-cavity reflection detection and arc judgment.

In one embodiment, the process of determining whether an arc is generated in the plasma chamber based on the comparison results in the above step S16 may include the following determination:

According to the situation that the absolute value of the difference is less than the set reflection coefficient threshold and meets the set analysis and judgment conditions, it is determined whether there is arc generation or no arc generation in the plasma cavity.

It can be understood that in the above embodiment, whether there is an arc generated in the cavity can be directly determined by judging whether |Γ _cur – Γ _aver |<Γ _th is true. In this embodiment, in order to further improve the accuracy of judging arc generation Degree, by judging whether |Γ _cur – Γ _aver |<Γ _th is true and whether it meets the set analysis and judgment conditions, we can more accurately judge whether there is an arc in the cavity.

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

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

Specifically, if it is determined that |Γ _cur –Γ _aver |<Γ _th reaches N times continuously, it can be determined that no arc is generated in the current plasma cavity.

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

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

Specifically, if |Γ _cur –Γ _aver |>Γ _th within a period of time (that is, a set period, the specific length can be determined based on actual application monitoring experience or the statistics of historical monitoring data), the limited number of times M or less (including 1 time ) and discontinuous, it can be determined that no arc is generated in the current plasma cavity.

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

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

Specifically, if |Γ _cur –Γ _aver |>Γ _th is 1, then it can be determined that an arc is generated in the plasma cavity.

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

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

Specifically, if |Γ _cur –Γ _aver |>Γ _th is multiple times in succession (including 2 times), then it can be determined that an arc is generated in the plasma cavity.

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

In one embodiment, the detection time period of arc detection sampling includes multiple detection time periods from small to large. Set the reflection coefficient threshold to a manually set coefficient threshold or a system adaptively set coefficient threshold. The above plasma cavity arc suppression method may also include the following steps:

Starting from the minimum detection time period, if the frequency of arc generation in the plasma cavity is less than the set frequency threshold, the detection time will be extended to the next larger detection time period;

Otherwise, the detection time remains unchanged, and the coefficient threshold set adaptively by the system is increased by multiples or fixed. Adaptive growth in the form of value growth.

Specifically, the reflection coefficient threshold Γ _th can be set manually (such as based on work experience or historical monitoring data, etc.), or can be set adaptively by the system. Among them, when the system adaptively sets it, an initial value Γ _th can be set first to introduce the initial comparison process of |Γ _cur – Γ _aver |<Γ _th . The initial value Γ _th can be artificially set, or it can be It is calculated using dynamic data or historical data of Γ _cur and Γ _aver .

In actual monitoring, you can set several detection time periods from small to large, such as but not limited to 8us, 16us, 32us... and so on. First set the minimum detection time period, such as 8us, and then set the minimum detection time period in this minimum detection time period. Within , the frequency of arc generation is evaluated by |Γ _cur – Γ _aver |<Γ _th . If the frequency of arc generation is less than the preset frequency threshold, the detection time period is lengthened to the next larger detection time period, such as 16us or 32us. The coefficient threshold set by the system adaptively can remain unchanged. Within the minimum detection time period, if the frequency of arc generation is higher than the preset frequency threshold, the value of Γ _th will be increased, such as using a multiple increase or a fixed value increase, or first obtaining |Γ _cur – Γ _aver | The dynamic maximum value is then used as a multiple or fixed value increase as the adjusted Γ _th .

Through the above steps, system adaptive coefficient threshold adjustment can be achieved, thereby further improving the accuracy of judging arc generation.

In one embodiment, the above plasma cavity arc suppression method further includes the steps:

If it is determined according to the comparison result that no arc is generated in the plasma cavity, the PID controller is maintained in the general control state. Among them, the general control status includes:

Maintain the current working status of the control module;

Continuously conduct arc detection sampling to obtain the reflection coefficient in the plasma cavity;

Record the average reflection coefficient under current normal working conditions;

Record the operating parameters of the control module;

Record the operating variable parameters of the unit device at the output end, set the current normal working time node as the restoration node, and continuously update it.

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 , and determines that the general control state is maintained when no arc is generated. , at this time, the PID controller maintains the work of the current control module and continuously monitors the gamma value, while recording the following working parameters of the current time node: (a) the average gamma value of normal operation; (b) the PID controller's response to the control module at the output end. Operation parameters; (c) The operation variable parameters of the unit device that runs the power output at the output end, and the time node is identified as the restoration node. The data of this restoration node is in the general control state. Will be constantly updated.

In one embodiment, regarding the process of instructing the freezing of the operating parameters of the radio frequency power supply system and finally the corresponding restoration node through the state machine in step S16 above, the specific process may include the following processing:

The state machine instructs the 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 terminal to freeze the operating variable parameters of each unit device.

Specifically, when it is determined that an arc has occurred, the PID controller switches to the shutdown control state, and its state machine will also switch to the operating state, instructing each module to freeze the working parameters of the final corresponding restoration node, such as instructing the module responsible for gamma mean calculation to freeze the gamma mean. , instruct the control module of the PID controller to freeze its operating parameters, and instruct the output end of the docking 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 for a period of time X (including Potential fall time + zero potential + potential rise).

As shown in Figure 3, it is a schematic diagram of ARC suppression at each stage. The entire ARC occurrence process can be divided into seven stages A-G. The meaning and processing method 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 return to normal working status as quickly as possible after the arc is eliminated.

Table 1

As shown in Figure 4, it is a schematic diagram of one of the ARC processing flows. The entire process can be divided into two parts: the Gamma mean calculation and comparison part and the PID save suspension part. Through the above processing method, high-precision detection and suppression of ARC is achieved, and at the same time, the system can be restored to work as quickly as possible after arc extinguishing with low arc extinguishing cost.

It should be understood that although the various steps in the flowcharts of Figures 1 and 4 follow the directions of arrows, are displayed, but these steps are not necessarily performed in the order indicated by the arrows. Unless explicitly stated in this article, there is no strict order restriction on the execution of these steps, and these steps can be executed in other orders. Moreover, at least some of the steps in Figures 1 and 4 may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily executed at the same time, but may be executed at different times. These sub-steps or The execution order of the stages is not necessarily sequential, but may be performed in turn or alternately with other steps or sub-steps of other steps or at least part of the stages.

In one embodiment, as shown in FIG. 5 , a plasma cavity 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 cavity 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 instruct the freezing of the working parameters of the last corresponding restoration node of the RF power supply system through the state machine, suspend the arc detection sampling, and cut off the docking through the control module of the PID controller when it is determined that an arc is generated in the plasma cavity based on the comparison results. Electrical output at the output of the plasma chamber. 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 resume arc detection sampling according to the operating parameters after the arc in the plasma cavity disappears.

The above-mentioned plasma cavity arc suppression device 100 obtains the instantaneous and average reflection coefficient in the plasma cavity through arc detection sampling, and then compares it with the set reflection coefficient threshold to accurately determine whether there is an arc in the plasma cavity. If it is determined that there is an arc in the plasma cavity, generated, then the state machine will be used to instruct the RF power supply system to freeze the working parameters of the last corresponding restoration node, suspend arc detection sampling, and cut off the power output of the output end of the docking plasma cavity through the control module of the PID controller, that is, suspend the RF power supply to the plasma After the arc in the plasma chamber disappears, the control module of the PID controller is instructed according to the working parameters to restore the power output at the output end and resume arc detection sampling, that is, restore the power output of the RF power supply to the plasma chamber. This achieves high-precision suppression of arcs in the plasma cavity.

Compared with the traditional method, the above scheme greatly improves the accuracy of judging whether an arc is generated through the comparison mechanism between the average reflection coefficient (also called gamma average) and the critical value. When determining arc generation, the state machine is used to instruct the freezing system to work parameters corresponding to the last restoration node, suspend arc detection and suspend power output, so that after the arc disappears in the cavity, it can be accurately and quickly restored according to the frozen working parameters. The power output realizes high-precision intra-cavity arc suppression processing, and the arc suppression cost is lower, the efficiency is higher, and the adaptability is stronger.

In one embodiment, the process of determining whether there is arc generation in the plasma cavity based on the comparison results includes:

According to the situation that the absolute value of the difference is less than the set reflection coefficient threshold and meets the set analysis and judgment conditions, it is determined whether there is arc generation or no arc generation in the plasma cavity.

In one embodiment, setting analysis and judgment conditions includes:

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

In one embodiment, setting 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 the set period, it is determined that no arc is generated in the plasma cavity; M is a positive integer not less than 1.

In one embodiment, setting analysis and judgment conditions includes:

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

In one embodiment, setting analysis and judgment conditions includes:

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

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

The above method also includes the steps:

Starting from the minimum detection time period, if the frequency of arc generation in the plasma cavity is less than the set frequency threshold, the detection time will be extended to the next larger detection time period;

Otherwise, the detection time remains unchanged, and the coefficient threshold set by the system is adaptively increased by a multiple increase or a fixed value increase.

In one embodiment, the above method further includes the steps:

If it is determined based on the comparison results that no arc is generated in the plasma cavity, the PID controller is maintained in the general control state;

Among them, the general control status includes:

Maintain the current working status of the control module;

Continuously conduct arc detection sampling to obtain the reflection coefficient in the plasma cavity;

Record the average reflection coefficient under current normal working conditions;

Record the operating parameters of the control module;

Record the operating variable parameters of the unit device at the output end, set the current normal working time node as the restoration node, and continuously update it.

In one embodiment, the process of freezing the operating parameters of the corresponding restoration node of the radio frequency power supply system through a state machine instruction includes:

The state machine instructs the 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 terminal to freeze the operating variable parameters of each unit device.

In one embodiment, the step of obtaining the reflection coefficient in the plasma cavity through arc detection sampling includes:

Use timed and fixed-point sampling to obtain the instantaneous reflection coefficient;

The average reflection coefficient is calculated using all the instantaneous reflection coefficients obtained by the current sampling; among them, each sampling, mean calculation and threshold comparison are all single-time interval synchronous multi-thread processing.

For specific limitations on the plasma cavity arc suppression device 100, please refer to the above limitations on the plasma cavity arc suppression method, which will not be described again here. Each module in the above-mentioned plasma cavity arc suppression device 100 can be implemented in whole or in part by software, hardware, and combinations thereof. Each of the above modules can be embedded in or independent of the PID controller or processor in the radio frequency power supply system in the form of hardware, or can be stored in the memory in the radio frequency power supply system in the form of software to facilitate the call and execution of the PID controller or processor. The operations corresponding to each of the above modules.

In one embodiment, as shown in FIG. 6 , 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 . RF power supply 22 is electrically connected to plasma chamber 26 through PID controller 24. The PID controller 24 is used to implement the following arc suppression processing steps:

Obtain the reflection coefficient in the plasma cavity through arc detection sampling; the reflection coefficient includes instantaneous reflection coefficient and average reflection coefficient;

Compare the absolute value of the difference between the instantaneous reflection coefficient and the average reflection coefficient with the set reflection coefficient threshold;

If it is determined that an arc is generated in the plasma cavity according to the comparison result, freeze the operating parameters of the last corresponding restoration node of the radio frequency power supply 22 system, suspend arc detection sampling, and cut off the power output of the output end connected to the plasma cavity;

After the arc in the plasma cavity disappears, the power output at the output end is restored according to the working parameters and the Complex arc detection sampling.

It can be understood that for the specific limited description of the functions implemented by the above-mentioned PID controller 24, please refer to the corresponding limited description of the plasma cavity arc suppression method above, and will not be described again here. The specific electrical connection relationships and mechanical structures of the various components in the above-mentioned RF power supply system 200 can be understood by referring to the electrical and mechanical structures of the RF power supply 22 system existing in the art, and will not be described in detail in this specification.

Figure 7 shows the structure of the ARC processing module divided according to the implementation function. The PID controller 24 can be divided into a control module that controls the output end of the docking plasma chamber 26 and an ARC processing module as shown in Figure 7. The ARC processing module , which 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 from the measurement information of the real-time detection sample and calculate the corresponding average reflection coefficient. The comparison unit can be used to compare |Γ _cur –Γ _aver | with Γ _th . The ARC detection unit can be used to determine whether there is arc generation in the cavity based on the comparison results. The state machine can be used to implement the corresponding indication control function shown in the above embodiment.

Those skilled in the art can understand that Figures 6 and 7 are only block diagrams of some product entities and functional structures related to the solution of this application, and do not constitute a detailed limitation of the radio frequency power supply system to which the solution of this application is applied. The specific radio frequency power system It may include more or fewer components than shown in the above figure, or combine certain components, or have a different component arrangement, as determined by the actual type of RF power supply system.

The above-mentioned radio frequency power supply system 200 obtains the instantaneous and average reflection coefficient in the plasma cavity through arc detection sampling, and then compares it with the set reflection coefficient threshold to accurately determine whether an arc is generated in the plasma cavity. If it is determined that an arc is generated in the plasma cavity, Then, the working parameters of the last corresponding restoration node of the radio frequency power supply system will be frozen through the state machine instruction, arc detection sampling will be suspended, and the power output of the output end of the docking plasma cavity will be cut off through the control module of the PID controller 24, that is, the radio frequency power supply to the plasma cavity will be suspended. After the arc in the plasma chamber disappears, the control module of the PID controller 24 is instructed according to the operating parameters to restore the power output at the output end and resume arc detection sampling, that is, restore the power of the RF power supply to the plasma chamber 26 output, thereby achieving high-precision suppression of arcs in the plasma cavity.

Compared with the traditional method, the above scheme greatly improves the accuracy of judging whether an arc is generated through the comparison mechanism between the average reflection coefficient (also called gamma average) and the critical value. When determining arc generation, the state machine is used to indicate the operating parameters of the freezing system's last corresponding restoration node, pause arc detection, and pause. Power output, so that after the arc in the cavity disappears, 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 .

In one embodiment, a computer-readable storage medium is also provided, with a computer program stored thereon. When the computer program is executed by the processor, the following processing steps are implemented: obtaining the reflection coefficient in the plasma cavity through arc detection sampling; the reflection coefficient includes Instantaneous reflection coefficient and average reflection coefficient; compare the absolute value of the difference between the instantaneous reflection coefficient and the average reflection coefficient with the set reflection coefficient threshold; if it is determined that an arc is generated in the plasma cavity according to the comparison result, the RF power supply system will be frozen through the state machine instruction Finally, corresponding to the working parameters of the restoration node, the arc detection sampling is suspended and the power output of the output end of the docking plasma cavity is cut off through the control module of the PID controller; after the arc in the plasma cavity disappears, the control module of the PID controller is instructed according to the working parameters. The group restores power output at the output terminal and resumes arc detection sampling.

In one embodiment, when the computer program is executed by the processor, the added steps or sub-steps in the above embodiments of the plasma cavity arc suppression method can also be implemented.

Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be completed by instructing relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. , when executed, the computer program may include the processes of the above method embodiments. Any reference to memory, storage, database or other media used in the embodiments 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 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 chain Synchlink DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

The technical features of the above embodiments can be combined in any way. To simplify the description, 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, all possible combinations should be used. It is considered to be within the scope of this manual.

The above embodiments only express several implementation modes of the present application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the patent application. It should be noted that, for those of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present application, and these all fall within the protection scope of the present application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims (13)

1. A plasma cavity arc suppression method, characterized by including the following steps:

   Obtain the reflection coefficient in the plasma cavity through arc detection sampling; the reflection coefficient includes the instantaneous reflection coefficient and the 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 that an arc is generated in the plasma cavity according to the comparison result, the state machine is used to instruct the RF power supply system to freeze the working parameters of the last corresponding restoration node, suspend the arc detection sampling, and cut off the docking through the control module of the PID controller. power output at the output of the plasma chamber;

   After the arc in the plasma cavity disappears, the control module of the PID controller is instructed according to the operating parameters to restore the power output of the output end and resume the arc detection sampling.
2. The plasma cavity arc suppression method according to claim 1, wherein the process of determining whether there is arc generation in the plasma cavity according to the comparison results includes:

   According to the fact that the absolute value of the difference is less than the set reflection coefficient threshold and satisfies the set analysis and judgment conditions, it is determined whether there is arc generation or no arc generation in the plasma cavity.
3. The plasma cavity arc suppression method according to claim 2, wherein the set analysis and judgment conditions include:

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

   If the absolute value of the difference is greater than the set reflection coefficient threshold M times and is discontinuous within a set period, it is determined that no arc is generated in the plasma cavity; M is a positive integer not less than 1.
5. The plasma cavity arc suppression method according to claim 2, wherein the set analysis and judgment conditions include:

   If the absolute value of the difference is greater than the set reflection coefficient threshold for one time, it is determined that an arc is generated in the plasma cavity.
6. The plasma cavity arc suppression method according to claim 2, 3 or 5, characterized in that the set analysis and judgment conditions include:

   If the absolute value of the difference is greater than the set reflection coefficient threshold for N consecutive times, it is determined that an arc is generated in the plasma cavity; N is a positive integer not less than 2.
7. The plasma cavity arc suppression method according to claim 1, wherein the detection time period of the arc detection sampling includes multiple detection time periods from small to large, and the set reflection coefficient threshold is manually set. Coefficient threshold or coefficient threshold set adaptively by the system;

   The method also includes the steps of:

   Starting from the minimum detection time period, if the frequency of arc generation in the plasma cavity is less than the set frequency threshold, the detection time is lengthened to the next larger detection time period;

   Otherwise, the detection time is kept unchanged, and the coefficient threshold set adaptively by the system is adaptively increased by a multiple increase or a fixed value increase.
8. The plasma cavity arc suppression method according to claim 1, characterized in that the method further includes the steps:

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

   Wherein, the general control status includes:

   Maintain the current working status of the control module;

   Continuously conduct arc detection sampling to obtain the reflection coefficient in the plasma cavity;

   Record the average reflection coefficient under current normal working conditions;

   Record the operating parameters of the control module;

   Record the operating variable parameters of the unit device at the output end, set the current normal working time node as the restoration node, and continuously update it.
9. The plasma cavity arc suppression method according to claim 8, characterized in that the process of freezing the working parameters of the final corresponding restoration node of the radio frequency power supply system through a state machine includes:

   The state machine instructs the freezing of the last average reflection coefficient in the normal working state, instructs the control module to freeze operating parameters, and instructs the output end to freeze the operating variable parameters of each unit device.
10. The plasma cavity arc suppression method according to claim 1, wherein the step of obtaining the reflection coefficient in the plasma cavity through arc detection sampling includes:

    Obtain the instantaneous reflection coefficient by using timed and fixed-point sampling;

    The average reflection coefficient is calculated using all instantaneous reflection coefficients obtained by current sampling; wherein, each sampling, mean calculation and threshold comparison are all single time interval synchronous multi-thread processing.
11. A plasma cavity arc suppression device, characterized in that the device includes:

    The detection sampling module is used to obtain the reflection coefficient in the plasma cavity through arc detection sampling; The reflection coefficient includes instantaneous reflection coefficient and average reflection coefficient;

    A coefficient comparison module, 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 is used to instruct through the state machine to freeze the operating parameters of the last corresponding restoration node of the radio frequency power supply system, suspend the arc detection sampling, and control it through the PID controller when it is determined that an arc is generated in the plasma cavity based on the comparison result. The module cuts off the power output of the output end connected to the plasma cavity;

    An output recovery module is configured 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 operating parameters after the arc in the plasma cavity 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, and 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:

    Obtain the reflection coefficient in the plasma cavity through arc detection sampling; the reflection coefficient includes the instantaneous reflection coefficient and the 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 that an arc is generated in the plasma cavity according to the comparison result, freeze the operating parameters of the last corresponding reduction node of the radio frequency power supply system, suspend the arc detection sampling, and cut off the power output of the output end connected to the plasma cavity;

    After the arc in the plasma cavity disappears, the power output of the output end is restored according to the operating parameters and the arc detection sampling is restored.
13. A computer-readable storage medium with a computer program stored thereon, characterized in that when the computer program is executed by a processor, the steps of the plasma cavity arc suppression method described in any one of claims 1 to 10 are implemented.