Method and apparatus for detecting arcing in a plasma processing chamber

Abstract

The application discloses a kind of detection method and detection device of arc of plasma processing chamber, the method includes: by radio frequency power source, radio frequency power is transported to plasma processing cavity, and reaction gas in plasma processing cavity is ignited to form plasma;The variance and average of reflected power signal of radio frequency power source in the length of sampling time period are obtained in real time by controller;The number of peak value of reflected power signal in the length of corresponding sampling time period is estimated according to the variance and average of reflected power signal by controller, and when the number of peak value of reflected power signal is less than preset threshold, it is judged that arc discharge occurs.The application realizes that micro-arc in vacuum reaction cavity arc is detected quickly, so as to know the purpose of the defect state of corresponding wafer in time.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of plasma processing device, and particularly relates to a method and device for detecting arc in a plasma processing chamber. BACKGROUND

[0002] Current plasma processing devices, such as plasma enhanced chemical vapor deposition (PE-CVD) systems, plasma etching systems and sputtering systems, are widely used in semiconductor production equipment in the whole process of modern electronic device production. The plasma processing device uses the working principle of a vacuum reaction chamber to process semiconductor substrates and plasma panel substrates. The working principle of the vacuum reaction chamber is to introduce a reaction gas containing a proper etching agent or deposition source gas into the vacuum reaction chamber, and then input radio frequency energy into the vacuum reaction chamber to activate the reaction gas to ignite and maintain the plasma, so as to etch the material layer on the surface of the substrate or deposit the material layer on the surface of the substrate, respectively, and then process the semiconductor substrate and the plasma panel. The breakdown of dielectric material caused by the higher potential of the plasma than the side wall of the vacuum reaction chamber or the accumulation of surface charge of the substrate can cause micro-arc in the vacuum reaction chamber. The micro-arc caused by the high plasma potential in the vacuum reaction chamber usually lasts for several microseconds. When the micro-arc occurs, a large current discharge occurs in the plasma processing device, and a current / power spike is generated in the various circuits input into the plasma reaction chamber.

[0003] As Figure 1As shown, the prior art generally detects the voltage of the output end of the ESC power supply 30 connected to the electrostatic chuck 20 to determine the arc discharge phenomenon, the output voltage fluctuation of the DC high voltage power supply (ESC power supply) 30 is detected by a detector 40, the PLC circuit 50 is connected to the output end of the detector, and the corresponding information is transmitted to the main controller 60 after processing the detected voltage signal. Since the ESC power supply 30 is provided with a voltage dividing circuit, the DC high voltage is reduced to a low enough voltage signal so that it can be detected and transmitted to the main controller 60. The detector 40 is designed to detect the voltage-stable DC signal output by the output high voltage DC power supply 30, so the sampling rate is low, and the discharge time is extremely short (a few milliseconds), which cannot be sampled and detected. Even if a higher level detector 40 is selected to sample the voltage fluctuation signal caused by the discharge, since the communication time of the PLC circuit 50 and the main controller 60 in the plasma processing device is now about 200 ms, the time of arc discharge, especially micro-arc discharge, is much less than 200 ms (such as a few milliseconds), and for the common pulse type plasma processing process (the output RF power changes rapidly in a pulse type, such as 10K pulse frequency), the high-speed change of the RF power itself causes the detected voltage signal to also change at a high speed, which will cause a large number of false discharge signals. Moreover, this false signal has a large delay and cannot correspond to the current process step, so it cannot be distinguished whether it is caused by the output power mutation or the discharge. The existence of micro-arc will cause the pollutants from the side wall of the vacuum reaction chamber to accumulate on the wafer 10 being processed in the vacuum reaction chamber, thereby causing a defective wafer 10 that will affect the progress of subsequent processes, and thus there is an urgent need for a method that can effectively detect micro-arc. SUMMARY

[0004] The purpose of the present application is to provide a method and device for detecting arc in a plasma processing chamber, which can quickly detect micro-arc in the arc in the vacuum reaction chamber, so as to know the defect state of the corresponding wafer in time.

[0005] In order to achieve the above purpose, the present application realizes the following technical scheme:

[0006] A method for detecting arc in a plasma processing chamber, comprising: delivering RF power to the plasma processing chamber by an RF power source, igniting the reaction gas in the plasma processing chamber to form plasma; the controller acquires the variance and average value of the reflected power signal of the RF power source within a sampling time period in real time; the controller estimates the number of peak values of the reflected power signal within the sampling time period according to the variance and average value of the reflected power signal, and determines that arc discharge occurs when the number of peak values of the reflected power signal is less than a predetermined threshold.

[0007] Optionally, the radio frequency power source acquires the value of the reflected power signal every 1ms to 10ms.

[0008] Optionally, the controller acquires the variance and average value of the reflected power signal of the radio frequency power source in the sampling time period length in real time, and the step of acquiring the variance and average value of the reflected power signal of the radio frequency power source in the sampling time period length comprises: the radio frequency power source calculates the variance and average value of the reflected power signal in the sampling time period length and returns the variance and average value to the controller.

[0009] Optionally, the controller estimates the number k of the peak values of the reflected power signal in the sampling time period length according to the following formula:

[0010]

[0011] In the formula, μ represents the average value of the reflected power signal in the sampling time period length; σ represents the variance of the reflected power signal in the sampling time period length; and n represents the number of the values of the reflected power signal in the sampling time period length. 2

[0012] Optionally, the number of the values of the reflected power in the sampling time period length is n, and the preset threshold value is:

[0013] Optionally, the ratio of the peak value and the minimum value of the reflected power signal in the sampling time period length is r, and the value range of r is 10 2 ~ 10 5 .

[0014] Optionally, the number of the radio frequency power sources is two, and the radio frequency power sources output high frequency and low frequency radio frequency power to the reaction cavity respectively, and the two radio frequency power sources independently or jointly send the variance and average value of the reflected power signal to the controller.

[0015] Optionally, the sampling time period length t ranges from 200ms to 400ms.

[0016] Optionally, the sampling time period length t ranges from 200ms to 400ms.

[0017] Optionally, when the number k of the peak values of the reflected power signal is less than the preset threshold value in the sampling time period length, a warning information is issued.

[0018] ​​In another aspect, the present application provides an arc detection device for detecting arc discharge in a plasma processing chamber, comprising: a radio frequency power source and a controller disposed outside the plasma processing chamber. The radio frequency power source is configured to deliver radio frequency power into the plasma processing chamber to ignite a plasma formed by a reaction gas introduced into the plasma processing chamber, and to detect a reflected power signal reflected from the plasma processing chamber back to the radio frequency power source. The controller is configured to obtain a variance and a mean of the reflected power signal from the radio frequency power source within a sampling time period. The controller is configured to estimate a number of spikes of the reflected power signal within the sampling time period based on the variance and the mean of the reflected power signal, and to determine that an arc discharge occurs when the number of spikes of the reflected power signal is less than a predetermined threshold.

[0019] Optionally, the radio frequency power source obtains the value of the reflected power signal every 1-10 ms.

[0020] Optionally, the radio frequency power source calculates the variance and the mean of the reflected power signal within the sampling time period and returns them to the controller.

[0021] Optionally, the controller estimates the number of spikes k of the reflected power signal within the sampling time period using the following formula:

[0022]

[0023] wherein represents the mean of the reflected power signal within the sampling time period; σ 2 represents the variance of the reflected power signal within the sampling time period; and n represents the number of values of the reflected power signal within the sampling time period.

[0024] Optionally, the number of values of the reflected power within the sampling time period is n, and the predetermined threshold is:

[0025] Optionally, the ratio of the spike value to the minimum value of the reflected power signal within the sampling time period is r, and r is in the range of 10 2 ~ 10 5 .

[0026] Optionally, the number of radio frequency power sources is two, which output high frequency and low frequency radio frequency power to the reaction chamber, respectively, and independently or jointly send the variance and the mean of the reflected power signal to the controller.

[0027] Optionally, the sampling time period length t is in the range of 200ms < t ≤ 400ms.

[0028] Optionally, the system further comprises a warning device connected to the controller; when the number k of the peak values of the reflected power signal is less than the preset threshold value within the sampling time period length, the warning device issues a warning information.

[0029] Optionally, the controller is further configured to accumulate the number k when the warning information is issued, and obtain an accumulated value; when the accumulated value is greater than or equal to a preset detection threshold value, the warning device issues a detection device alarm information, and immediately suspends the wafer manufacturing process.

[0030] The present application has at least one of the following advantages:

[0031] The present application estimates the number of peak values of the reflected power signal within the sampling time period length by the variance and the average value of the reflected power signal, and determines that arc discharge occurs when the number of peak values of the reflected power signal is less than a preset threshold value. Since the RF power source has a high-speed data collector inside, it can send or count the reflected power information in real time and at a high sampling rate (~10μs interval), and transmit the counted reflected power information to the controller. Thus, the controller determines the number of peak values of the reflected power signal within the sampling time period length according to the reflected power information, and determines whether the discharge in the plasma processing chamber is caused by micro-arc discharge, or by ignition failure or frequency adjustment operation, etc. based on the number. This method has better detection accuracy.

[0032] Further, micro-arc in the arc in the plasma chamber can be quickly detected, so as to timely know the defect state of the corresponding wafer.

[0033] The present application prompts the occurrence of micro-arc by the issued warning information, so that people can intuitively know that micro-arc discharge occurs in the plasma chamber, and can roughly know the defect state of the wafer.

[0034] The present application prompts too many micro-arc by the issued detection device alarm information, which reaches the degree of stopping the equipment, so as to improve the wafer yield and save the manufacturing cost. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 It is a main structure diagram of the detection device for arc in the plasma processing chamber in the prior art;

[0036] Figure 2a It is a timing diagram of the reflected power signal detected by the RF power source when a micro-arc event occurs in a measurement scheme;

[0037] Figure 2b A timing diagram of the reflected power signal detected by the RF power source when a high reflected power signal caused by micro-arc occurs for a measurement scheme;

[0038] Figure 3 A flowchart of a method for detecting an arc in a plasma processing chamber according to an embodiment of the present application

[0039] Figure 4 A timing diagram of the reflected power signal detected by the RF power source when a high reflected power signal caused by micro-arc occurs for a measurement scheme according to an embodiment of the present application. DETAILED DESCRIPTION

[0040] As described in the background, the existing arc detection device for the plasma processing chamber has the following defects: the detector has a very low sampling rate, and cannot sample and detect the discharge with very short discharge time. Even if a higher level detector is selected to sample the voltage fluctuation signal caused by the discharge, for the existing common pulse plasma processing process, the detected voltage signal changes rapidly due to the high-speed change of the RF power, which will cause a large number of false discharge signals, and it is impossible to distinguish whether it is caused by the output power mutation or the discharge.

[0041] According to the feedback signals that the RF power source can provide, such as the average value and the maximum value, there is a micro-arc detection method, which takes the average reflected power value (Pr_Avg) or the maximum reflected power value (Pr_Max) of the reflected power signal of the RF power source feedback and the difference (Pr_Delta) between the average reflected power value (Pr_Avg) as the standard for detecting the occurrence of micro-arc. The standard can be Pr_Avg> threshold value, or Pr_Delta> threshold value.

[0042] For example, as shown in Figure 2a , it gives a technical scheme for judging micro-discharge by using the maximum value P and the average value A, Figure 2a The upper graph in the figure is a real reflected power signal variation diagram generated according to time, but in actual work, such detailed data cannot be monitored from the RF source. If the technology can obtain Figure 2a such data, the arc discharge condition can be directly judged. The data that can be obtained from the RF source can only be the average value A and the maximum value P waveform graph of the reflected power signal after data processing as shown in Figure 2a The lower graph in the figure is the average value A and the maximum value P waveform graph of the reflected power signal after data processing. Because data processing needs time, the data obtained from the RF source is not as detailed as the upper graph in the figure. Figure 2aThe average and maximum values ​​in the diagram below will have a time delay compared to the actual situation shown in the diagram above. When no micro-arc occurs, the difference between the average value A and the maximum value P is relatively small. When the reflected power changes abruptly, the difference between the two will increase, indicating that a micro-discharge event has occurred.

[0043] However, in actual use, this criterion can also be triggered by high reflected power caused by impedance mismatch. That is, there is a high reflected power signal during the sampling period, but this high reflected power signal lasts for a long time and has a large peak width. This kind of reflected power signal is not caused by micro-arc discharge, but may also be caused by ignition failure or preset / frequency adjustment errors.

[0044] For example, such as Figure 2b As shown, Figure 2b The peaks in the upper graph last longer and do not occur instantaneously, but after data processing... Figure 2b The waveforms in the lower middle figure and Figure 2a The waveforms in the following figure are basically the same. The maximum value P fed back by the RF power source is also a straight line much higher than the average value A; that is, the maximum value P is greater than the average value A. However, in reality, this spike is a sudden change caused by RF adjustment, not a sudden change caused by micro-arc discharge. Therefore, using the maximum value P being greater than the average value A as the standard for detecting micro-arc discharge will lead to inaccurate detection.

[0045] Based on the above research, this embodiment provides a method for detecting electric arcs in a plasma processing chamber. The method estimates the number of peak values ​​of the reflected power signal within the corresponding sampling time period by using the variance and average value of the reflected power signal. When the number of peak values ​​is less than a preset threshold, the peak width is small, and this type of reflected power signal can be identified as being caused by micro-arc discharge, thus determining that arc discharge has occurred. Therefore, this method can not only quickly detect micro-arcs in a vacuum reaction chamber to promptly determine the corresponding wafer defect state, but also has better detection accuracy.

[0046] The method for detecting arc in plasma processing chamber and the detection device are further described in detail below in combination with the drawings and specific embodiments. The advantages and features of the present application will be more apparent from the following description. It should be noted that the drawings are very simplified and all use non-precise proportions, only for the purpose of facilitating, clarifying and assisting in describing the embodiments of the present application. For the purpose of making the purposes, features and advantages of the present application more obvious and easy to understand, please refer to the drawings. It should be understood that the structures, proportions and sizes shown in the drawings of the present application are only used to understand and read the disclosed content by those skilled in the art, and are not used to limit the implementation of the present application, so they do not have technical significance. Any modification of structure, change of proportion relationship or adjustment of size, which does not affect the effect and purpose that can be achieved by the present application, should still fall within the scope of the disclosed technology.

[0047] As shown in the drawings, Figure 3 The method for detecting arc in plasma processing chamber provided by the present embodiment comprises the following steps: S1, delivering radio frequency power to the plasma processing chamber by a radio frequency power source to ignite the reaction gas in the plasma processing chamber to form plasma.

[0048] S2, acquiring the variance and average value of the reflected power signal of the radio frequency power source in the sampling time period by a controller.

[0049] S3, estimating the number of peak values of the reflected power signal in the sampling time period by the controller according to the variance and average value of the reflected power signal, and determining that arc discharge occurs when the number of peak values of the reflected power signal is less than a preset threshold value.

[0050] Therefore, when the number of peak values of the reflected power signal is less than the preset threshold value, it is known that the peak width value of the reflected power signal is small, and it is determined that the reflected power signal is caused by micro-arc discharge, so it is determined that arc discharge occurs in the plasma processing chamber. Compared with the detection method in the prior art which uses average reflected power value Pr_Avg or difference value Pr_Delta as a discrimination standard, the present embodiment has better detection accuracy.

[0051] In the present embodiment, the step of acquiring the variance and average value of the reflected power signal of the radio frequency power source in the sampling time period by the controller comprises: the radio frequency power source calculates the variance and average value of the reflected power signal in the sampling time period and returns them to the controller. Therefore, the present embodiment can quickly detect micro-arc in the vacuum reaction chamber to know the defect state of the corresponding wafer in time.

[0052] In the embodiment, the radio frequency power source obtains the value of the reflected power signal every 1ms-10ms. In the sampling time length, the radio frequency power source can obtain n (n is a natural number) values of the reflected power signal, and the n values of the reflected power signal adopt a series X i , i∈[1, n] represents.

[0053] A series of values X i The variance and the mathematical definition of the average value X are as follows:

[0054]

[0055] And the quotient of the variance and the square of the average value is:

[0056]

[0057] Assuming an extreme case as an approximation of the model, the series X i is a series of distribution with only 2 values, that is, assuming that in the series X i , there are k peak values X_max of the reflected power signal and n-k X_min except the peak value, then the middle term r is calculated by the following formula:

[0058]

[0059] According to the mathematical formula of the variance σ 2 and the average value of the reflected power signal, the ratio of the variance σ 2 and the square of the average value of the reflected power signal is calculated:

[0060]

[0061] Substituting r into the above formula, then:

[0062]

[0063] Approximate processing of the above formula gives:

[0064]

[0065] In the embodiment, the controller estimates the number k of the peak values of the reflected power signal in the sampling time length according to formula (8).

[0066] In the embodiment, in the sampling time length, the number of values of the reflected power is n, and the preset threshold is:

[0067] In this embodiment, within the sampling time period, the ratio of the peak value to the minimum value of the reflected power signal is r, and the value of r ranges from 10. 2 ~10 5 That is, once the minimum value is determined, the range of r can be considered as having a peak.

[0068] like Figure 4 As shown, Figure 4 The figure above shows a very wide spike, which is not due to the change in reflected power caused by micro-arc discharge. Figure 4 The figure below shows the variance F and average value A of the reflected power signal fed back by the RF power source. Then, the k value is calculated according to formula (8). The obtained k value is greater than the preset threshold, indicating that there are multiple time points with peak values ​​far exceeding the average value between 5.2 seconds and 5.4 seconds in the sampling period. The k value being greater than the preset threshold means that in the actual reflected power changes, the peak value duration is very long. Therefore, it can be determined that... Figure 4 The spike shown in the above figure is not caused by micro-arcs, but by other factors.

[0069] Conversely, if the value of k is very small, less than the preset threshold, it indicates that the duration of the spike is short. Figure 4 The peaks shown in the above figure are caused by micro-arcs, not by other factors, thus avoiding misjudgments caused by relying solely on maximum and average values.

[0070] Therefore, the detection standard adopted in this embodiment has better accuracy than the existing micro-arc detection scheme.

[0071] In this embodiment, the number of radio frequency power sources is two, which respectively output high-frequency and low-frequency radio frequency power to the reaction cavity. The two radio frequency power sources independently or jointly transmit the variance and average value of the reflected power signals to the controller. In this embodiment, the number of radio frequency power sources is not limited to this and may be more than two.

[0072] In the pulsed processing technology, the radio frequency power source outputs pulsed power with a pulse frequency of 100Hz-100KHz, and the controller receives the radio frequency power signal to obtain the micro-arc signal of the impedance stabilization matching stage in each pulse step.

[0073] The embodiment also includes: issuing a warning information when the number k of the peak values of the reflected power signal is less than the preset threshold within the sampling time period length. When the number k of the peak values of the reflected power signal is greater than the preset threshold, the issued warning information is ignored. Because the duration of the micro-arc discharge is short and the duration of the radio frequency power fluctuation is long within the sampling time period length, if one peak value corresponds to each time point, if the number is too large, the actual situation is probably continuous peaks rather than isolated peaks caused by the micro-arc discharge. The embodiment prompts the generation of the micro-arc through the issued warning information, so that a person can intuitively know that the micro-arc discharge occurs in the plasma chamber, and the defect state of the wafer can be roughly known.

[0074] In the embodiment, the number k corresponding to the issued warning information is accumulated to obtain an accumulated value, and when the accumulated value is greater than or equal to a preset detection threshold, a detection device alarm information is issued, and the wafer preparation process is immediately suspended.

[0075] The embodiment prompts that too many micro-arc discharges occur through the issued detection device alarm information, which reaches the degree that the equipment can be stopped, so that the wafer yield can be improved and the manufacturing cost can be saved.

[0076] In the embodiment, the preset threshold is used to determine whether the discharge occurs when a single high-reflected power event occurs, that is, the discharge is prompted when the number k is less than the preset threshold. The preset detection threshold is used to cope with the situation that a small amount of discharge does not affect the overall process under certain conditions, and the equipment needs to be stopped for maintenance when multiple discharges occur, so the preset detection threshold is the accumulated value of the number of discharges. That is, in the embodiment, the preset threshold is less than the preset detection threshold.

[0077] The detection device alarm information and the warning information can be one or two and can be issued at the same time.

[0078] On the other hand, based on the same inventive concept, the embodiment also provides a detection device for arc in a plasma processing chamber for detecting arc discharge in the plasma processing chamber, which comprises a radio frequency power source and a controller arranged outside the plasma processing chamber. The radio frequency power source is used to deliver radio frequency power into the plasma processing chamber to ignite the reaction gas introduced into the plasma processing chamber to form plasma, and simultaneously detect a reflected power signal reflected from the plasma processing chamber to the radio frequency power source. The controller obtains the variance and the average value of the reflected power signal of the radio frequency power source within a sampling time period length in real time. The controller estimates the number of peak values of the reflected power signal within the sampling time period length according to the variance and the average value of the reflected power signal, and determines that arc discharge occurs when the number of peak values of the reflected power signal is less than a preset threshold.

[0079] In the embodiment, the radio frequency power source obtains the value of the reflected power signal every 1ms-10ms.

[0080] In the embodiment, the radio frequency power source calculates the variance and average value of the reflected power signal in the sampling time length and returns them to the controller.

[0081] In the embodiment, the controller estimates the number k of the peak values of the reflected power signal in the sampling time length by using the following formula:

[0082]

[0083] In the formula, μ represents the average value of the reflected power signal in the sampling time length; σ represents the variance of the reflected power signal in the sampling time length; and n represents the number of the values of the reflected power signal in the sampling time length. 2

[0084] In the embodiment, the number of the values of the reflected power in the sampling time length is n, and the preset threshold is:

[0085] In the embodiment, the ratio of the peak value and the minimum value of the reflected power signal in the sampling time length is r, and the value of r ranges from 10 2 5

[0086] In the embodiment, the number of the radio frequency power sources is two, which output high frequency and low frequency radio frequency power to the reaction cavity respectively, and the two radio frequency power sources send the variance and average value of the reflected power signal to the controller independently or in combination.

[0087] In the embodiment, the sampling time length t ranges from 200ms to 400ms.

[0088] In the embodiment, before the arc detection, the controller can further determine whether to enter the radio frequency power stable output interval by excluding the process of clamping or unclamping the substrate when the output power is greater than 500W, so as to prevent capturing the false signal caused by the change of the radio frequency power which does not actually represent the arc. That is, the output power of the radio frequency power source in the radio frequency power stable output interval is greater than 500W.

[0089] ​​​​In the embodiment, the number of the radio frequency power sources is two, which output high frequency and low frequency radio frequency power to the reaction cavity respectively, and the two radio frequency power sources send the variance and average value of the reflected power signal to the controller independently or in combination.

[0090] In the pulse processing process, the radio frequency power source outputs pulse power with a pulse frequency of 100 Hz-100 KHz, and the controller receives the radio frequency power signal to obtain the micro-arc signal in the impedance stabilization matching stage in each pulse step.

[0091] In the embodiment, the device further comprises a warning device connected to the controller, which sends a warning signal according to the frequency of the discharge phenomenon detected by the controller; or the warning device sends a warning signal according to the number k of the peak value of the reflected power signal in the length of the sampling time period calculated by the controller.

[0092] The device further comprises a warning device connected to the controller, which sends a warning signal according to the frequency of the discharge phenomenon detected by the controller.

[0093] When the number k of the peak value of the reflected power signal in the length of the sampling time period is less than the preset threshold, the warning device sends a warning message.

[0094] In the embodiment or some other embodiments, the controller is further configured to accumulate the number k corresponding to the sending of the warning message to obtain an accumulated value, and when the accumulated value is greater than or equal to a preset detection threshold, the warning device sends a detection device warning message and immediately suspends the wafer preparation process.

[0095] In summary, the embodiment provides a method for detecting arc in a plasma processing cavity, which obtains the variance and average value of the reflected power signal of the radio frequency power source in the length of the sampling time period by a controller. The controller estimates the number of the peak value of the reflected power signal in the length of the sampling time period according to the variance and average value of the reflected power signal, and determines that arc discharge occurs when the number of the peak value of the reflected power signal is less than a preset threshold.

[0096] Therefore, it can be known that, when the number of the peak values of the reflected power signal is less than the preset threshold value, it is known that the peak width value of the reflected power signal is small, and it is determined that the reflected power signal is caused by micro-arc discharge, and it is determined that the arc discharge occurs in the plasma processing cavity. Compared with the detection method in the prior art which uses the average reflected power value Pr_Avg and the reflected power value difference Pr_Delta as the discrimination standard, the embodiment has better detection accuracy. Further, the micro-arc in the arc in the vacuum reaction cavity can be quickly detected, so as to know the defect state of the corresponding wafer in time.

[0097] It should be noted that, in this document, the terms "comprising", "including", or any other variant thereof are intended to cover a non-exclusive inclusion, so that a process, method, article, or apparatus that includes a list of elements not only includes those elements, but also includes other elements not expressly listed or inherent to such process, method, article, or apparatus. Without more limitations, an element defined by the statement "comprising a" does not exclude the existence of additional identical elements in the process, method, article, or apparatus that includes the element.

[0098] Although the content of the present application has been described in detail through the above preferred embodiments, it should be recognized that the above description should not be considered as a limitation of the present application. After reading the above content, various modifications and alternatives of the present application will be apparent to those skilled in the art. Therefore, the protection scope of the present application should be defined by the appended claims.

Claims

1. A method for detecting an arc within a plasma processing chamber, the method comprising: The application relates to a method for detecting arc discharge in a plasma processing chamber. The method comprises the following steps: a radio frequency power source is used to deliver radio frequency power to the plasma processing chamber to ignite reaction gas in the plasma processing chamber to form plasma; a controller is used to acquire the variance and average value of the reflected power signal of the radio frequency power source in a sampling time period; 2. The method of detecting an arc within a plasma processing chamber as recited in claim 1, wherein, the controller estimates the number of sharp peaks of the reflected power signal in the sampling time period according to the variance and average value of the reflected power signal, and determines that arc discharge occurs when the number of sharp peaks of the reflected power signal is less than a preset threshold value.

3. The method of claim 2, wherein the step of detecting an arc within the plasma processing chamber further comprises the step of: The radio frequency power source acquires the value of the reflected power signal every 1-10 ms. ​ 4. The method of claim 1, wherein the step of detecting an arc within the plasma processing chamber further comprises the step of: determining the presence of an arc within the plasma processing chamber by comparing the voltage and current signals to a predetermined threshold value. The controller acquires the variance and average value of the reflected power signal of the radio frequency power source in a sampling time period. wherein denotes the average value of the reflected power signal over the length of the sampling time period; σ 2 denotes the variance of the reflected power signal over the length of the sampling time period; n denotes the number of values of the reflected power signal over the length of the sampling time period.

5. The method of claim 1, wherein the step of detecting an arc within the plasma processing chamber further comprises the step of: determining the presence of an arc within the plasma processing chamber by comparing the voltage and current signals to a predetermined threshold value. The number of values of the reflected power signal within the length of the sampling time period is n, and the preset threshold is:

6. The method of detecting an arc within a plasma processing chamber as recited in claim 1, wherein, The ratio of the peak value and the minimum value of the reflected power signal in the length of the sampling time period is r, and r is in the range of 10 2 ~ 10 5 .

7. The method of detecting an arc within a plasma processing chamber as defined in claim 1, wherein, The controller estimates the number of sharp peaks of the reflected power signal in the sampling time period according to the following formula:

8. The method of detecting arcing in a plasma processing chamber as recited in claim 1, wherein, The number of radio frequency power sources is two, and high-frequency and low-frequency radio frequency power is output to the reaction chamber; the two radio frequency power sources independently or jointly send the variance and average value of the reflected power signal to the controller. The application further relates to a device for detecting arc discharge in a plasma processing chamber.

9. The method of detecting an arc within a plasma processing chamber as recited in claim 4, wherein, The sampling time period t is 200-400 ms. The application further relates to a device for detecting arc discharge in a plasma processing chamber.

10. The method of detecting an arc within a plasma processing chamber as defined in claim 9, wherein, When the number of sharp peaks of the reflected power signal is less than the preset threshold value in the sampling time period, the device issues a warning message.

11. An apparatus for detecting an electrical arc in a plasma processing chamber for detecting an electrical arc discharge in a plasma processing chamber, characterized by, The device accumulates the number k of the warning message to obtain an accumulated value, and issues a detection device alarm message and immediately stops wafer preparation when the accumulated value is greater than or equal to a preset detection threshold value. The application relates to a device for detecting arc discharge in a plasma processing chamber. The device comprises a radio frequency power source and a controller which are arranged outside the plasma processing chamber. The radio frequency power source is used to deliver radio frequency power to the plasma processing chamber to ignite reaction gas in the plasma processing chamber to form plasma; the radio frequency power source simultaneously detects the reflected power signal of the radio frequency power source reflected from the plasma processing chamber. The controller acquires the variance and average value of the reflected power signal of the radio frequency power source in a sampling time period.

12. The apparatus for detecting an arc within a plasma processing chamber as defined in claim 11, wherein, The controller estimates the number of sharp peaks of the reflected power signal in the sampling time period according to the variance and average value of the reflected power signal, and determines that arc discharge occurs when the number of sharp peaks of the reflected power signal is less than a preset threshold value.

13. The apparatus for detecting an arc within a plasma processing chamber as defined in claim 12, wherein, The radio frequency power source acquires the value of the reflected power signal every 1-10 ms.

14. The apparatus for detecting an arc within a plasma processing chamber as defined in claim 13, wherein, The radio frequency power source calculates the variance and average value of the reflected power signal in the sampling time period and returns the values to the controller. wherein denotes the average value of the reflected power signal over the length of the sampling time period; σ 2 denotes the variance of the reflected power signal over the length of the sampling time period; n denotes the number of values of the reflected power signal over the length of the sampling time period.

15. The apparatus for detecting an arc within a plasma processing chamber as defined in claim 11, wherein, The number of values of the reflected power signal within the length of the sampling time period is n, and the preset threshold is:

16. The apparatus for detecting an arc within a plasma processing chamber as recited in claim 11, wherein, The ratio of the peak value and the minimum value of the reflected power signal in the length of the sampling time period is r, and r is in the range of 10 2 ~ 10 5 .

17. The apparatus for detecting an arc within a plasma processing chamber as defined in claim 11, wherein, The controller estimates the number of sharp peaks of the reflected power signal in the sampling time period according to the following formula:

18. The apparatus for detecting an arc within a plasma processing chamber as recited in claim 11, wherein, The number of radio frequency power sources is two, and high-frequency and low-frequency radio frequency power is output to the reaction chamber; the two radio frequency power sources independently or jointly send the variance and average value of the reflected power signal to the controller. The application further relates to a device for detecting arc discharge in a plasma processing chamber. The sampling time period length t ranges from 200 ms to 400 ms.

19. The apparatus for detecting an arc within a plasma processing chamber as defined in claim 11, wherein, Further comprising a warning device connected to the controller; When the number k of the peak values of the reflected power signal is less than the preset threshold value within the sampling time period length, the warning device issues a warning information.

20. The apparatus for detecting an arc within a plasma processing chamber as recited in claim 19, wherein, The controller is further configured to accumulate the number k corresponding to the time when the warning information is issued to obtain an accumulated value, and when the accumulated value is greater than or equal to a preset detection threshold value, the warning device issues a detection device alarm information and immediately suspends the wafer preparation process.

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