Method for detecting the state of cooling water of a remote plasma source
By real-time detection of cavity temperature changes in a remote plasma source and the establishment of a temperature rise rate database, the problem of lag in cooling water anomaly detection is solved, enabling rapid and accurate monitoring of cooling water status, reducing equipment costs and maintenance difficulty, and improving equipment reliability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SHANGHAI LIZHAO TECH CO LTD
- Filing Date
- 2026-04-12
- Publication Date
- 2026-07-14
AI Technical Summary
Existing remote plasma source cooling water detection methods are difficult to detect abnormal cooling water conditions quickly and accurately, resulting in high equipment hardware costs and maintenance difficulties. Furthermore, they are slow to respond to sudden abnormal fluctuations in flow rate and water temperature, which may lead to overheating and damage to components.
By controlling a remote plasma source to increase output power at different rates, the cavity temperature is detected in real time, a database of normal and abnormal temperature rise rates is established, a benchmark and abnormal threshold are determined based on the temperature rise rate, and the current temperature rise rate is compared in real time to determine the cooling water status.
It enables rapid and accurate cooling water status detection, reduces system cost and complexity, improves equipment reliability and responsiveness, and avoids equipment damage caused by abnormal cooling water.
Smart Images
Figure CN122385014A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of semiconductor equipment technology, and in particular to a method for detecting cooling water in plasma equipment. Background Technology
[0002] Plasma processing equipment is used in various industries that manufacture chips, including semiconductors, magnetic read / write, magnetic storage, and microelectromechanical systems (MEMS). The use of radio frequency (RF) power supplies or systems to excite plasma has been widely adopted in the field of plasma processing.
[0003] Remote Plasma Sources (RPS) have wide applications in semiconductor manufacturing. As highly integrated, high-power devices, stable and efficient water cooling is essential for ensuring continuous and stable operation. Currently, some RPS systems are equipped with flow sensors or solenoid valves to monitor cooling water. However, this only monitors routine conditions such as whether the cooling water is running. It may be slow to respond to sudden abnormal fluctuations in flow rate or water temperature, and may struggle to respond to minor blockages in the pipeline. In severe cases, it can even lead to prolonged overheating and damage to components. Furthermore, the use of flow sensors or solenoid valves increases the hardware cost and maintenance complexity of the equipment.
[0004] Therefore, a method for detecting the cooling water status of a remote plasma source is needed, which can quickly and accurately detect the occurrence of abnormal cooling water status and promptly implement corresponding maintenance measures. Summary of the Invention
[0005] One objective of this application is to provide a method for detecting the cooling water status of a remote plasma source, so as to quickly and accurately detect abnormal cooling water status.
[0006] This application provides a method for detecting the cooling water status of a remote plasma source, comprising: under normal cooling water conditions, controlling the remote plasma source to increase from an initial output power to different target output powers at different rates, and detecting the temperature of the cavity in real time to obtain the normal temperature rise rate of the cavity corresponding to the different rates and different target output powers; under abnormal cooling water conditions, controlling the remote plasma source to increase from the initial output power to the different target output powers at different rates, and detecting the temperature of the cavity in real time to obtain the abnormal temperature rise rate of the cavity corresponding to the different rates and different target output powers; determining a reference threshold for normal cooling water operation based on the normal temperature rise rate, and determining an abnormal threshold for abnormal cooling water operation based on the normal temperature rise rate and the abnormal temperature rise rate; and measuring the current temperature rise rate, current output power, and current power increase rate of the remote plasma source cavity, comparing the current temperature rise rate with the reference threshold and the abnormal threshold, and determining the cooling water status based on the current output power.
[0007] Optionally, controlling the remote plasma source to increase from the initial output power to different target output powers at different rates, and detecting the temperature of the cavity in real time to obtain the normal temperature rise rate of the cavity corresponding to the different rates and different target output powers includes: controlling the remote plasma source to increase to the target low output power, the target normal output power, and the target maximum output power at different rates, thereby obtaining the normal temperature rise rate of the cavity corresponding to the different rates and different target output powers.
[0008] Optionally, the different rates include controlling the remote plasma source to increase power at low, medium, and high speeds.
[0009] Optionally, controlling the remote plasma source to increase from the initial output power to different target output powers at different rates, and detecting the temperature of the cavity in real time to obtain the abnormal temperature rise rate of the cavity corresponding to the different rates and different target output powers includes: controlling the remote plasma source to increase to the target low output power, the target normal output power, and the target maximum output power at different rates, thereby obtaining the abnormal temperature rise rate of the cavity corresponding to the different rates and different target output powers.
[0010] Optionally, the different rates include controlling the remote plasma source to increase power at low, medium, and high speeds.
[0011] Optionally, abnormal cooling water conditions include coupled faults such as reduced cooling water flow, increased cooling water temperature, or reduced cooling water flow and increased temperature.
[0012] Optionally, the abnormal threshold includes: a warning threshold, set between the maximum fluctuation of the normal temperature rise rate and the minimum abnormal temperature rise rate under the minor fault level; or set as the maximum of the maximum fluctuation of the normal temperature rise rate and the average probability of the abnormal temperature rise rate under the minor fault level, wherein the average probability of the abnormal temperature rise rate is based on the average of the abnormal temperature rise rate under the minor fault level and the standard deviation of the abnormal temperature rise rate under the minor fault level; wherein the minor fault level refers to a slight decrease in cooling water flow or a slight increase in cooling water temperature.
[0013] Optionally, the abnormal threshold includes: an alarm threshold, set as the maximum value among the warning threshold plus a margin and the 5th percentile of the abnormal temperature rise rate under the moderate fault level; or set as the maximum value among the warning threshold plus a margin and the minimum value of the abnormal temperature rise rate under the moderate fault level; or set between the maximum value of the fluctuation of the normal temperature rise rate and the minimum value of the abnormal temperature rise rate under the moderate fault level; wherein, the moderate fault level refers to a moderate reduction in cooling water flow, a moderate increase in cooling water temperature, or a slight coupling fault in cooling water.
[0014] Optionally, comparing the current temperature rise rate with a reference threshold and an abnormal threshold, and determining the cooling water status based on the current output power, includes: determining the cooling water to be in a normal state when the current temperature rise rate is less than or equal to the reference threshold; determining the cooling water to be slightly deviating from the normal state when the current temperature rise rate is greater than the reference threshold and less than or equal to the warning threshold, if the current output power is in a high-power state; determining the cooling water to be in a potential fault warning state when the current output power is in a low-power state; determining the cooling water to be in a medium-level fault alarm state when the current temperature rise rate is greater than the warning threshold and less than or equal to the alarm threshold, if the current output power is in a medium-high-power state; determining the cooling water to be in a confirmed fault alarm state when the current output power is in a low-power state; and determining the cooling water to be in a serious fault state when the current temperature rise rate is greater than the alarm threshold.
[0015] This application infers the state and performance of the cooling system by directly monitoring the temperature response characteristics (temperature rise rate) of the RPS cavity during operation. As one of the most important cooling components, the cavity temperature can sensitively and promptly reflect changes in cooling performance. Furthermore, the temperature signal can directly utilize existing cavity temperature data, which can be calculated and analyzed using conventional computing devices without requiring additional hardware, thus reducing system cost, complexity, and potential failure points, and improving reliability. When determining the state of the cooling system, the current RPS output power is also considered to more accurately determine the cooling water state and allow for more appropriate response measures. Attached Figure Description
[0016] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.
[0017] Figure 1 A flowchart of a method for detecting the cooling water status of a remote plasma source according to an embodiment of this application is shown. Detailed Implementation
[0018] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application. All other embodiments obtained by those skilled in the art based on the embodiments in this application without inventive effort are within the scope of protection of this application.
[0019] It should be noted that, unless there is a conflict, the various features in the embodiments of this application can be combined with each other, and all are within the protection scope of this application. Furthermore, although functional modules are divided in the device schematic diagram and a logical order is shown in the flowchart, in some cases, the steps shown or described can be performed in a different order than the module division in the device or the order in the flowchart.
[0020] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the scope of this application. The term "and / or" as used in this specification includes any and all combinations of one or more of the associated listed items. Furthermore, technical features involved in the different embodiments of this application described below may be combined with each other as long as they do not conflict with each other.
[0021] According to one embodiment of this application, such as Figure 1 As shown, a method for detecting the cooling water status of a remote plasma source is provided, including:
[0022] Step 102: Under normal cooling water conditions, control the remote plasma source to increase from the initial output power to different target output powers at different rates, and detect the temperature of the cavity in real time to obtain the normal temperature rise rate of the cavity corresponding to the different rates and different target output powers;
[0023] Step 104: Under abnormal cooling water conditions, control the remote plasma source to increase from the initial output power to the different target output power at different rates, and detect the temperature of the cavity in real time to obtain the abnormal temperature rise rate of the cavity corresponding to the different rates and different target output powers;
[0024] Step 106: Determine the baseline threshold for normal operation of cooling water based on the normal temperature rise rate, and determine the abnormal threshold for abnormal operation of cooling water based on the normal temperature rise rate and the abnormal temperature rise rate.
[0025] Step 108: Measure the current temperature rise rate, current output power, and current power increase rate of the remote plasma source cavity, compare the current temperature rise rate with the reference threshold and the abnormal threshold, and determine the cooling water status based on the current output power.
[0026] First, in step 102, the detection method establishes the cavity temperature rise rate under normal cooling water conditions, i.e., the baseline temperature rise rate. Specifically, under normal cooling water conditions (e.g., maximum rated cooling water flow rate and minimum rated temperature), the remote plasma source is controlled to increase the initial output power to different target output powers at different rates. The initial output power can be zero power, and the target output power can be the target low output power, the target normal output power, and the target maximum output power. The highest target output power is the maximum rated power. Cavity temperature data is collected in real time and processed. The temperature rise rate is obtained by subtracting the temperature data from the previous second (or 0.5 seconds, etc., which can be adjusted according to the actual situation) from the current temperature data. Using the target output power P and the rate S as a set of operating points, a normal temperature rise rate database for all operating conditions can be established.
[0027] In one embodiment, Table 1 shows the temperature rise rate record under normal cooling water conditions. The power level P represents the target output power. In this column, Low indicates low power, such as 20%-30% of the rated output power; Norm indicates normal power, such as 80% of the rated output power; and Max indicates maximum power, such as close to 100% of the rated output power. In the power ramp-up rate S column, Slow indicates slow power ramp-up to achieve the smoothest process temperature rise curve; Norm indicates normal power ramp-up to achieve a standard process temperature rise curve; and Fast indicates rapid power ramp-up, the fastest temperature rise rate allowed by the process. The temperature rise rate R column records the cavity temperature rise rate R_normal for each operating condition. This is the baseline threshold for each operating point. For each industrial control operating point (P, S), multiple repeated tests can be performed under normal cooling water conditions to obtain the temperature rise rate dataset.
[0028] serial number Power level P Power Boost Rate S Cooling water status Temperature rise rate R 1 Low Slow normal R_low_slow_normal 2 Low Norm normal R_low_norm_normal 3 Low Fast normal R_low_fast_normal 4 Norm Slow normal R_norm_slow_normal 5 Norm Norm normal R_norm_norm_normal 6 Norm Fast normal R_norm_fast_normal 7 Max Slow normal R_max_slow_normal 8 Max Norm normal R_max_norm_normal 9 Max Fast normal R_max_fast_normal
[0029] Table 1. Temperature rise rate record under normal cooling water conditions throughout the entire operating cycle.
[0030] Next, in step 104, the cooling water is adjusted to simulate abnormal conditions, including reducing the cooling water flow rate, increasing the cooling water temperature, and simultaneously reducing the flow rate and increasing the temperature. Under abnormal cooling water conditions, the remote plasma source is controlled to increase the output power to different target powers at different rates. The highest value of this target power is the rated maximum power. The cavity temperature data is collected in real time, and the resulting temperature rise rate is processed. Using the target output power P and the rate S as a set of operating points, a full-condition abnormal temperature rise rate test database can be established for specific abnormal conditions.
[0031] In one embodiment, Table 2 shows the temperature rise rate record for all operating conditions under abnormal cooling water flow conditions. The power level P represents the target output power. In this column, Low indicates low power, such as 20%-30% of the rated output power; Norm indicates normal power, such as 80% of the rated output power; and Max indicates maximum power, such as close to 100% of the rated output power. In the power boost rate S column, Slow indicates slow power boost to achieve the smoothest process temperature rise curve; Norm indicates normal rate power boost to achieve a standard process temperature rise curve; and Fast indicates rapid power boost, the fastest temperature rise rate allowed by the process. The cooling water state is 90% of the normal flow rate Q, i.e., a slight reduction in cooling water flow. The temperature rise rate R column records the abnormal temperature rise rate R of the cavity for each operating condition under the condition of slightly reduced cooling water flow. For each control point (P, S), multiple repeated tests can be performed under this abnormal cooling water condition to obtain the temperature rise rate dataset.
[0032] serial number Power level P Power Boost Rate S Cooling water status (flow rate) Temperature rise rate R 1-1 Low Slow 0.9Q (slight reduction) R_low_slow_flow1 1-2 Low Norm 0.9Q R_low_norm_flow1 1-3 Low Fast 0.9Q R_low_fast_flow1 1-4 Norm Slow 0.9Q R_norm_slow_flow1 1-5 Norm Norm 0.9Q R_norm_norm_flow1 1-6 Norm Fast 0.9Q R_norm_fast_flow1 1-7 Max Slow 0.9Q R_max_slow_flow1 1-8 Max Norm 0.9Q R_max_norm_flow1 1-9 Max Fast 0.9Q R_max_fast_flow1
[0033] Table 2 Record of Abnormal Temperature Rise Rate under Abnormal Cooling Water Flow Conditions
[0034] Similarly, under the conditions of 70% of the normal flow rate Q (i.e., moderate reduction in cooling water flow) and 50% of the normal flow rate Q (i.e., severe reduction in cooling water flow), the abnormal temperature rise rate of the cavity under all operating conditions, R_P_S_flow2 and R_P_S_flow3, can be recorded respectively, where P is selected from three power levels: Low, Norm, and Max, and S is selected from three power increase rates: Slow, Norm, and Fast.
[0035] In one embodiment, Table 3 shows the temperature rise rate record for all operating conditions under abnormal cooling water temperature conditions. The power level P represents the target output power; in this column, Low indicates low power, Norm indicates normal power, and Max indicates maximum power. In the power boost rate S column, Slow indicates slow power boost, Norm indicates normal power boost, and Fast indicates rapid power boost. The cooling water condition is a 5°C increase from normal temperature, i.e., a slight increase in cooling water temperature. The temperature rise rate R column records the abnormal temperature rise rate R of the cavity for each operating condition under the condition of a slight increase in cooling water temperature. For each industrial control point (P, S), multiple repeated tests can be performed under this abnormal cooling water condition to obtain the temperature rise rate dataset.
[0036] serial number Power level P Power Boost Rate S Cooling water status (temperature) Temperature rise rate R 2-1 Low Slow T+5℃ (slightly elevated) R_low_slow_temp1 2-2 Low Norm T+5℃ R_low_norm_temp1 2-3 Low Fast T+5℃ R_low_fast_temp1 2-4 Norm Slow T+5℃ R_norm_slow_temp1 2-5 Norm Norm T+5℃ R_norm_norm_temp1 2-6 Norm Fast T+5℃ R_norm_fast_temp1 2-7 Max Slow T+5℃ R_max_slow_temp1 2-8 Max Norm T+5℃ R_max_norm_temp1 2-9 Max Fast T+5℃ R_max_fast_temp1 serial number Power level P Power Boost Rate S Cooling water status (temperature) Temperature rise rate R
[0037] Table 3 Record of Abnormal Temperature Rise Rate under Abnormal Cooling Water Temperature Conditions (All Operating Conditions)
[0038] Similarly, under the conditions of normal temperature rise of 10℃ (i.e., moderate rise in cooling water temperature) and normal temperature rise of 15℃ (i.e., severe rise in cooling water temperature), the abnormal temperature rise rate of the cavity under all operating conditions, R_P_S_temp2 and R_P_S_temp3, can be recorded respectively, where P is selected from three power levels: Low, Norm, and Max, and S is selected from three power increase rates: Slow, Norm, and Fast.
[0039] In one embodiment, Table 4 shows the temperature rise rate record under full operating conditions under cooling water coupling fault conditions. The power level P represents the target output power; in this column, Low indicates low power, Norm indicates normal power, and Max indicates maximum power. In the power boost rate S column, Slow indicates slow power boost, Norm indicates normal power boost, and Fast indicates rapid power boost. The cooling water state is 90% of the normal flow rate Q and the temperature is 5°C above normal, i.e., a slight coupling state. The temperature rise rate R column records the abnormal cavity temperature rise rate R for each operating condition under the slight coupling state of the cooling water. For each industrial control point (P, S), multiple repeated tests can be performed under this abnormal cooling water condition to obtain the temperature rise rate dataset.
[0040] serial number Power level P Power Boost Rate S Cooling water status (flow rate, temperature) Temperature rise rate R 3-1 Low Slow 0.9Q, T+5℃ (slight coupling) R_low_slow_coup1 3-2 Low Norm 0.9Q, T+5℃ R_low_norm_coup1 3-3 Low Fast 0.9Q, T+5℃ R_low_fast_coup1 3-4 Norm Slow 0.9Q, T+5℃ R_norm_slow_coup1 3-5 Norm Norm 0.9Q, T+5℃ R_norm_norm_coup1 3-6 Norm Fast 0.9Q、T+5℃ R_norm_fast_coup1 3-7 Max Slow 0.9Q、T+5℃ R_max_slow_coup1 3-8 Max Norm 0.9Q、T+5℃ R_max_norm_coup1 3-9 Max Fast 0.9Q、T+5℃ R_max_fast_coup1
[0041] Table 4. Record of abnormal temperature rise rate under all operating conditions during cooling water coupling fault.
[0042] Similarly, when the cooling water flow rate is 50% of the normal flow rate Q and the temperature is 15°C higher than the normal temperature (i.e., severe coupling), the abnormal temperature rise rate of the cavity under all operating conditions, R_P_S_coup2, can be recorded, where P is selected from three power levels: Low, Norm, and Max, and S is selected from three power boost rates: Slow, Norm, and Fast.
[0043] The aforementioned abnormal cooling water conditions can be categorized into minor, moderate, and severe fault levels. A minor fault level refers to a slight reduction in cooling water flow rate. For example, the cooling water flow rate is 90% of the normal flow rate Q, or the cooling water temperature is 5°C higher than normal. A moderate fault level refers to a moderate reduction in cooling water flow rate, a moderate increase in cooling water temperature, or slight coupling between the cooling water and temperature. For example, the cooling water flow rate is 70% of the normal flow rate Q, and the cooling water temperature is 10°C higher than normal, or the cooling water flow rate is reduced by 10% and the temperature increases by 5°C. A severe fault level refers to a severe reduction in cooling water flow rate, a severe increase in cooling water temperature, or severe coupling between the cooling water and temperature. For example, the cooling water flow rate is 50% of the normal flow rate Q, and the cooling water temperature is 15°C higher than normal, or the cooling water flow rate is reduced by 50% and the temperature increases by 15°C.
[0044] It should be noted that the aforementioned 90%, 70%, or 50% of the normal cooling water flow rate Q, and the normal temperature increase of 5°C, 10°C, or 15°C, are not strictly limited to the stated flow rate ratios and temperature values, but can also include reasonable ranges near these values. These values are established to differentiate the level of cooling water malfunction (minor, moderate, and severe). Any value setting that can distinguish the level of cooling water malfunction can be considered within a reasonable range.
[0045] Similarly, as mentioned above, "Low" indicates low power, such as 20%-30% of the rated output power; "Norm" indicates normal power, such as 80% of the rated output power; and "Max" indicates maximum power, such as close to 100% of the rated output power. These values are not strictly limited to percentages of the rated output power and can also include a reasonable range around these values. The purpose of these values is to distinguish different levels of target output power; any value setting that can distinguish the level of target output power can be considered within a reasonable range.
[0046] Then, in step 106, a baseline threshold for normal cooling water operation is determined based on the normal temperature rise rate, and an abnormal threshold for abnormal cooling water operation is determined based on both the normal and abnormal temperature rise rates. The abnormal thresholds include a warning threshold, an alarm threshold, and an emergency shutdown threshold. Their determination methods are explained below.
[0047] The warning threshold R_warn is used for minor fault warnings. This threshold is set at a reasonable position between the upper limit of normal fluctuations and the lower limit of minor faults, ensuring that any signs of minor faults can be detected while avoiding frequent false alarms due to normal fluctuations. The method for determining the warning threshold R_warn involves the following steps:
[0048] Step 1: Calculate the upper limit of normal fluctuation (UCL) for each operating point.
[0049] For each operating point (P, S), after n repeated tests (e.g., n ≥ 10) under completely normal cooling water conditions, a dataset of normal temperature rise rates {R_normal_1, ..., R_normal_n} is obtained. The mean of this dataset, μ_normal(P, S), and the standard deviation of this dataset, σ_normal(P, S), are calculated. The upper limit of normal fluctuations (i.e., the maximum value that normal data can reach) is: UCL(P,S) = μ_normal(P,S) + kσ_normal(P,S), where k can be 2 to 3: a value of 2 covers 95% of normal data, and a value of 3 covers 99.7% of normal data. In one embodiment, k is 2.5.
[0050] Step 2: Collect minor fault data
[0051] For each operating point (P, S), abnormal temperature rise rate data for minor fault levels (FQ-L1, FT-L1) are obtained. FQ-L1 refers to an abnormal state with a slight reduction in cooling water flow (90% of the normal flow rate Q), and FT-L1 refers to an abnormal state with a slight increase in cooling water temperature (an increase of 5°C). Multiple tests are performed under each operating condition to obtain the dataset for minor faults: Minor(P,S)={RFQ-L1_1 ,..., RFQ-L1_m, RFT−L1_1,..., RFT-L1_p}
[0052] Step 3: Analyze the distribution of minor fault data
[0053] The following values were obtained from the calculation:
[0054] Minimum temperature rise rate for minor faults: R_min_minor(P, S) = min(S_minor)
[0055] Mean temperature rise rate for minor faults: μ_minor(P, S)
[0056] Standard deviation of temperature rise rate due to minor faults: σ_minor(P, S)
[0057] Step 4: Determine candidate values for the warning threshold R_warn
[0058] Based on the relationship between R_min_minor and UCL, there are two cases:
[0059] Case A: R_min_minor(P, S) > UCL(P, S)
[0060] The temperature rise rate of all minor faults exceeds the upper limit of normal fluctuation. In this case, the warning threshold can be set between the two: R_warn(P, S) = UCL(P, S) + α(Rmin_minor(P, S) - UCL(P, S))
[0061] Where α is the safety factor, typically taken as 0.3 to 0.5:
[0062] The smaller α is, the closer the threshold is to the UCL, and the more sensitive it is (which may increase false alarms).
[0063] The larger α is, the closer the threshold is to R_min_minor, and the more conservative it is (which may cause minor faults to be missed).
[0064] Case B: R_min_minor(P, S) ≤ UCL(P, S)
[0065] At least one type of minor fault has a temperature rise rate that falls within the normal fluctuation range. In this case, relying solely on the temperature rise rate is unreliable for detecting this type of fault. The following handling strategies are proposed:
[0066] Strategy B1: Set independent early warning thresholds for different fault types.
[0067] The relevant parameters of the system cooling water can be directly obtained through flow sensors and temperature sensors, and separate settings can be made for flow faults and temperature faults:
[0068] The flow fault parameter R_warn_flow is set to max(UCL, μ_FQ-L1 -σ_FQ-L1) based on FQ-L1 data, where μ_FQ-L1 is the mean of the abnormal temperature rise rate set collected for a slight decrease in cooling water flow, and σ_FQ-L1 is the standard deviation of the abnormal temperature rise rate set collected for a slight decrease in cooling water flow.
[0069] Temperature fault parameter R_warn_temp: Based on FT-L1 data, set to max(UCL, μ_FT-L1-σ_FT-L1), where μ_FT-L1 is the mean of the abnormal temperature rise rate set collected for slight increases in cooling water temperature, and σ_FT-L1 is the standard deviation of the abnormal temperature rise rate set collected for slight increases in cooling water temperature.
[0070] During real-time operation, the corresponding warning threshold is selected based on the above-mentioned flow fault parameters and temperature fault parameters.
[0071] Strategy B2: Introduce a probabilistic safety margin
[0072] If the system cannot obtain both temperature and flow rate parameters, the warning threshold can be set as follows:
[0073] R_warn(P,S)=max(UCL,μ_minor(P,S)-βσ_minor(P,S))
[0074] In this strategy, β is set to 1 to 2 (β=1 covers approximately 84% of minor fault data, and β=2 covers 97.7% of minor fault data). This strategy ensures that at least most minor faults can be detected.
[0075] Strategy B3: Downgrade Processing
[0076] If the risk tolerance is low, it can be stated that "the temperature rise rate index is not applicable to minor fault warnings" for this operating point, and instead rely entirely on direct cooling water parameters or extend the monitoring window (such as observing trend changes rather than single-point over-limits).
[0077] The alarm threshold R_alarm is used to identify moderate faults. The determination of this threshold should avoid excessive overlap with minor faults. The alarm threshold is determined conservatively to ensure that an alarm indicates the need for action. The method for determining the alarm threshold R_alarm involves the following steps:
[0078] Step 1: Collect data on moderate faults
[0079] For each operating point (P, S), abnormal temperature rise rate data for moderate fault levels (FQ-M1, FT-M1, FC-M1) were obtained. FQ-M1 refers to an abnormal state with a moderate reduction in cooling water flow (70% of the normal flow rate Q), FT-M1 to an abnormal state with a moderate increase in cooling water temperature (a 10°C increase), and FC-M1 to an abnormal state with mild cooling water coupling (a 10% reduction in cooling water flow and a 5°C temperature increase). Multiple tests were conducted under each operating condition to obtain a dataset of minor faults.
[0080] Extract the temperature rise rate data for all medium fault levels (FQ-M1, FT-M1, FC-M1) at the same operating point (P, S) to form a dataset: Smoderate(P,S)={RFQ-M1_1 ,..., RFQ-M1_m, RFT-M1_1 ,..., RFT-M1_p,RFC-M1_1 ,..., RFC-M1_q}
[0081] Step 2: Determine the "lower limit" of a moderate fault.
[0082] The following values were obtained from the calculation:
[0083] Minimum temperature rise rate for moderate faults: R_min_moderate(P, S) = min(S_moderate)
[0084] 5th percentile of temperature rise rate in moderate faults: Q5_moderate (i.e., 95% of moderate fault data are above this value)
[0085] The alarm threshold should be lower than R_min_moderate or Q5_moderate to ensure that most moderate faults are not missed.
[0086] Step 3: Consider the connection with early warning thresholds
[0087] To avoid excessive threshold jumps, R_alarm should be at least higher than R_warn by a certain margin, i.e.:
[0088] R_alarm(P, S)≥R_warn(P, S)+δ
[0089] Where δ is the minimum resolvable interval, which can be 0.5 × σ_normal or set according to engineering experience, for example, 0.1~0.3°C / s.
[0090] Step 4: Determine the final value of R_alarm
[0091] The following methods are available:
[0092] Method 1: Based on quantile method
[0093] R_alarm(P, S)=max(R_warn(P, S)+δ, Q5_moderate(P, S)×γ)
[0094] Where γ is the safety factor, typically between 0.9 and 1.0. A value of 0.9 means the alarm threshold is slightly below the 5th percentile, ensuring that at least 95% of moderate faults will trigger an alarm.
[0095] Method 2: Minimum Fault Value Method
[0096] R_alarm(P, S)=max(R_warn(P, S)+δ, R_min_moderate(P, S)×η)
[0097] Where η is taken as 0.85~0.95. When it is taken as 0.9, the alarm threshold is 90% of the minimum moderate fault value, leaving a 10% margin.
[0098] Method 3: Combining the upper limit of normal conditions with the lower limit of moderate fault conditions
[0099] R_alarm(P, S)=UCL(P, S)+θ(R_min_moderate(P, S)-UCL(P, S))
[0100] θ is set to 0.5~0.8, which is larger than α, to ensure that the alarm threshold is closer to the data of moderate faults.
[0101] Finally, in step 108, the current temperature rise rate, current output power, and current power boost rate of the remote plasma source cavity are measured. The current temperature rise rate is compared with a reference threshold and an abnormal threshold, and the cooling water status is determined based on the current output power. The current temperature rise rate R_cur, current output power P_cur, and power boost rate S_cur of the remote plasma source cavity are monitored in real time. Furthermore, the current temperature rise rate R_cur is compared with each threshold at the current operating point (P_cur, S_cur).
[0102] When R_cur ≤ the baseline threshold R_normal(P_cur, S_cur), and the cooling water is determined to be in a normal state under any current output power, the remote plasma equipment continues to operate without alarm.
[0103] When R_normal(P_cur, S_cur) < R_cur ≤ warning threshold R_warn(P_cur, S_cur), if the current output power is at a high power level (e.g., P_cur ≥ 70% of rated power), it is determined that the cooling water is slightly deviating from the normal state, so no alarm is needed, only an observational warning is given; if the current output power is at a low power level (e.g., P_cur < 30% of rated power), it is determined that the cooling water is in a potential fault warning state, so a "Level 1 Warning" is triggered, indicating that the cooling efficiency has decreased, abnormal temperature rise has occurred under low load, and a planned inspection of the cooling system is recommended.
[0104] When R_warn(P_cur, S_cur) < R_cur ≤ R_alarm(P_cur, S_cur), if the current output power is in a medium-high power state (e.g., P_cur ≥ 50% of rated power), the cooling water is judged to be a medium fault alarm, and a "Level 2 alarm" is triggered. It is recommended that the process operate at reduced power and maintenance be arranged immediately. If the current output power is in a low power state (e.g., P_cur < 50% of rated power), the cooling water is judged to be a confirmed fault alarm, and a "Level 2 alarm" is triggered. Power increase is prohibited, and maintenance should be carried out immediately.
[0105] When R_cur > R_alarm(P_cur, S_cur), under any current output power, if the cooling water is determined to be in serious fault condition, a "Level 3 Emergency Shutdown" will be triggered: the plasma source will be immediately and safely interrupted to avoid overheating and damage to the cavity.
[0106] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them; under the concept of this application, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of this application as described above, which are not provided in detail for the sake of brevity; although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.
Claims
1. A method for detecting the cooling water status of a remote plasma source, comprising: Under normal cooling water conditions, the remote plasma source is controlled to increase from the initial output power to different target output powers at different rates, and the temperature of the cavity is detected in real time to obtain the normal temperature rise rate of the cavity corresponding to the different rates and different target output powers. Under abnormal cooling water conditions, the remote plasma source is controlled to increase from the initial output power to the different target output power at different rates, and the temperature of the cavity is detected in real time to obtain the abnormal temperature rise rate of the cavity corresponding to the different rates and different target output powers. The baseline threshold for normal operation of cooling water is determined based on the normal temperature rise rate, and the abnormal threshold for abnormal operation of cooling water is determined based on the normal temperature rise rate and the abnormal temperature rise rate. as well as The current temperature rise rate, current output power, and current power increase rate of the remote plasma source cavity are measured. The current temperature rise rate is compared with a reference threshold and an abnormal threshold, and the cooling water status is determined based on the current output power.
2. The method according to claim 1, characterized in that, The method of controlling the remote plasma source to increase from the initial output power to different target output powers at different rates, and detecting the temperature of the cavity in real time to obtain the normal temperature rise rate of the cavity corresponding to the different rates and different target output powers includes: controlling the remote plasma source to increase to the target low output power, the target normal output power and the target maximum output power at different rates, thereby obtaining the normal temperature rise rate of the cavity corresponding to the different rates and different target output powers.
3. The method according to claim 2, characterized in that, The different rates include controlling the remote plasma source to increase power at low, medium, and high speeds.
4. The method according to claim 1, characterized in that, The method of controlling the remote plasma source to increase from the initial output power to different target output powers at different rates, and detecting the temperature of the cavity in real time to obtain the abnormal temperature rise rate of the cavity corresponding to the different rates and different target output powers includes: controlling the remote plasma source to increase to the target low output power, the target normal output power and the target maximum output power at different rates, thereby obtaining the abnormal temperature rise rate of the cavity corresponding to the different rates and different target output powers.
5. The method according to claim 4, characterized in that, The different rates include controlling the remote plasma source to increase power at low, medium, and high speeds.
6. The method according to any one of claims 1-5, characterized in that, Abnormal cooling water conditions include coupled faults such as reduced cooling water flow, increased cooling water temperature, or reduced cooling water flow and increased temperature.
7. The method according to claim 1, characterized in that, The abnormal thresholds include: The warning threshold is set between the maximum fluctuation of the normal temperature rise rate and the minimum abnormal temperature rise rate under the minor fault level; or The value is set to the maximum of the fluctuation maximum of the normal temperature rise rate and the average probability of the abnormal temperature rise rate under the minor fault level, wherein the average probability of the abnormal temperature rise rate is based on the average of the abnormal temperature rise rate under the minor fault level and the standard deviation of the abnormal temperature rise rate under the minor fault level. The minor fault level refers to a slight decrease in cooling water flow or a slight increase in cooling water temperature.
8. The method according to claim 7, characterized in that, The abnormal thresholds include: The alarm threshold is set as the pre-warning threshold plus the maximum value among the 5th percentiles of the abnormal temperature rise rate under a margin and a moderate fault level; or Set as the maximum of the aforementioned warning threshold plus a margin and the minimum abnormal temperature rise rate under moderate fault levels; or The value is set between the maximum fluctuation of the normal temperature rise rate and the minimum abnormal temperature rise rate under the moderate fault level. The moderate fault level refers to a moderate reduction in cooling water flow, a moderate increase in cooling water temperature, or a mild coupling fault in the cooling water.
9. The method according to claim 7 or 8, characterized in that, The step of comparing the current temperature rise rate with the reference threshold and the abnormal threshold, and determining the cooling water status based on the current output power, includes: When the current temperature rise rate is less than or equal to the reference threshold, the cooling water is determined to be in a normal state. When the current temperature rise rate is greater than the reference threshold and less than or equal to the warning threshold, if the current output power is in a high power state, the cooling water is determined to be slightly deviating from the normal state; if the current output power is in a low power state, the cooling water is determined to be in a potential fault warning state. When the current temperature rise rate is greater than the warning threshold and less than or equal to the alarm threshold, if the current output power is in a medium-high power state, the cooling water is determined to be a medium fault alarm; if the current output power is in a low power state, the cooling water is determined to be a confirmed fault alarm. When the current temperature rise rate is greater than the alarm threshold, the cooling water is determined to be in serious condition.