Semiconductor equipment flow calibration method

Abstract

The invention provides a semiconductor equipment flow calibration method, and relates to the technical field of semiconductor equipment, and the semiconductor equipment flow calibration method comprises the steps: setting a target gas flow through a flow controller, and conveying gas into a calibration cavity of a flow calibrator at the target gas flow; time-domain pressure signals in the calibration cavity are collected at a preset sampling frequency, the time-domain pressure signals are converted into frequency-domain pressure signals for selective filtering, real pressure changes and various noise interferences are effectively separated, and a steady-state section of a pressure change rate curve is selected as a calculation reference to calculate and obtain actually measured gas flow; and comparing the actually measured gas flow with the target gas flow, and calibrating the flow controller according to a comparison result. According to the scheme, the defects that a traditional multiple averaging method is low in efficiency and not thorough in noise suppression are overcome fundamentally, and high-precision and high-efficiency flow calibration is achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor equipment, in particular to a semiconductor equipment flow calibration method. BACKGROUND

[0002] In the semiconductor manufacturing process, the accurate control of gas flow is one of the key factors to ensure process stability and product quality. The flow controller (MFC) in the semiconductor equipment is widely used to regulate the gas flow, but it may drift or have errors after long-term use, so it is necessary to calibrate the flow controller (MFC) by the flow calibrator (MFV) periodically. The core of flow calibration is to calculate the actual gas flow by measuring the pressure change in the calibration cavity of the flow calibrator, so as to realize the comparison and calibration with the set target flow.

[0003] However, in the gas flow environment, the pressure signal in the calibration cavity is often disturbed by various factors, which will cause fluctuations in the pressure signal and affect the accuracy of flow calculation. In order to reduce the influence of these fluctuations, the traditional method often uses multiple calibration to take the average value, but this method not only takes a long time, but also cannot completely eliminate the interference of noise, and cannot meet the demand of high efficiency and precision calibration in modern semiconductor manufacturing. SUMMARY

[0004] The purpose of the present application is to provide a semiconductor equipment flow calibration method, which solves the problems of insufficient flow calibration accuracy due to pressure signal fluctuations in the calibration cavity and the influence of multiple calibration on calibration efficiency in the prior art.

[0005] In order to achieve the above purpose, the present application realizes by the following technical scheme: A semiconductor equipment flow calibration method, the semiconductor equipment comprising a flow controller and a flow calibrator, the flow calibrator comprising a calibration cavity, the calibration cavity of the flow calibrator being in communication with the flow controller to calibrate the flow controller; the flow calibration method comprising: setting a target gas flow by the flow controller, and delivering gas into the calibration cavity of the flow calibrator at the target gas flow; acquiring an original time domain pressure signal in the calibration cavity at a preset sampling frequency, converting the original time domain pressure signal into an original frequency domain pressure signal, and filtering the original frequency domain pressure signal to obtain a filtered frequency domain pressure signal; converting the filtered frequency domain pressure signal into a filtered time domain pressure signal, performing a derivation operation on the filtered time domain pressure signal to obtain a pressure derivative signal, and forming a pressure change rate curve from the pressure derivative signal; extracting a pressure change rate corresponding to a steady stage of a pressure rising stage in the pressure change rate curve as a reference pressure change rate; acquiring a temperature and a volume in the calibration cavity, and calculating a measured gas flow rate according to the reference pressure change rate, the temperature and the volume; comparing the measured gas flow rate with the target gas flow rate, and calibrating the flow controller according to a comparison result.

[0006] In some embodiments, the filtering processing includes: normalizing and low-pass filtering the original frequency domain pressure signal to filter out high-frequency noise components in the original frequency domain pressure signal and retain low-frequency effective components in the original frequency domain pressure signal.

[0007] In some embodiments, the high-frequency noise components are original frequency domain pressure signals with frequencies higher than a preset cutoff frequency, and the low-frequency effective components are original frequency domain pressure signals with frequencies lower than or equal to the preset cutoff frequency.

[0008] In some embodiments, the preset cutoff frequency is 1.

[0009] In some embodiments, the steady stage is a continuous section in the pressure change rate curve in the pressure rising stage, in which a fluctuation amplitude is continuously maintained within a preset tolerance threshold range for a preset time length.

[0010] In some embodiments, the reference pressure change rate is obtained by any one of the following ways: selecting a pressure change rate at any point in the steady stage as the reference pressure change rate, or calculating an average value of pressure change rates at multiple points in the steady stage as the reference pressure change rate.

[0011] In some embodiments, a calculation formula of the measured gas flow rate is: wherein Q is the measured gas flow rate, dP / dt is the reference pressure change rate, V is the volume of the calibration cavity, T is the temperature in the calibration cavity, R is a molar gas constant, and the value of R is 8.314 J / (mol·K).

[0012] In some embodiments, the flow calibrator further includes a downstream valve, which is in communication with an outlet of the calibration cavity and is configured to control opening and closing of the outlet of the calibration cavity. The flow calibration method further includes closing the downstream valve before delivering the gas to the calibration cavity.

[0013] In some embodiments, the flow controller delivers the gas to the calibration cavity through a first pipeline, the first pipeline is provided with a first pressure sensor for measuring pipeline pressure of the first pipeline; the flow calibrator further comprises a second pressure sensor for measuring intracavity pressure of the calibration cavity. The flow calibration method further comprises: Real-time monitoring of the pipeline pressure and the intracavity pressure variation trend, determining that the pipeline pressure presents an upward trend and / or the intracavity pressure stops rising, then opening the downstream valve.

[0014] In some embodiments, the flow calibrator further comprises a first upstream valve and a second upstream valve, the first end of the first upstream valve and the first end of the second upstream valve are both in communication with the flow controller, the second end of the first upstream valve and the second end of the second upstream valve are both in communication with the inlet of the calibration cavity; the flow capacity of the first upstream valve is configured to be greater than the second upstream valve, the flow controller delivers the gas to the calibration cavity through the first upstream valve or the second upstream valve; The flow calibration method further comprises: According to the target gas flow, the volume of the calibration cavity and the intracavity temperature, calculating a pressure change rate requirement value, comparing the pressure change rate requirement value with a preset pressure change rate threshold value; Determining that the pressure change rate requirement value is greater than the preset pressure change rate threshold value, then delivering the gas to the calibration cavity through the first upstream valve; Determining that the pressure change rate requirement value is less than or equal to the preset pressure change rate threshold value, then delivering the gas to the calibration cavity through the second upstream valve; Wherein, the calculation formula of the pressure change rate requirement value is: γ=(F×R×T) / V; In the formula, γ is the pressure change rate requirement value, F is the target gas flow, R is the molar gas constant, T is the intracavity temperature of the calibration cavity, and V is the volume of the calibration cavity.

[0015] Compared with the prior art, the present application has the following advantages: The present application converts the time domain pressure signal to the frequency domain pressure signal for selective filtering, effectively separates the real pressure change from various noise interference, and selects the steady state section of the pressure change rate curve as the calculation reference, fundamentally avoids the defects of low efficiency and incomplete noise suppression of the traditional multiple calibration average method, and realizes high-precision and high-efficiency flow calibration. Specifically, the pressure curve after filtering is smoother, and the fluctuation interference caused by high-frequency noise is effectively eliminated; the noise component of the corresponding pressure change rate curve is effectively suppressed, and the reference pressure change rate extracted from the steady state section improves the accuracy of the measured gas flow calculation. Compared with multiple calibration average, the present method can ensure the calculation accuracy of the measured gas flow on the basis of reducing the calibration times; at the same time, through the temperature compensation formula under the variable temperature condition and the pressure change rate demand value prediction mechanism cooperating with the double upstream valve structure, the effective calibration range is expanded and the accuracy in the full range is ensured; combined with the abnormal response mechanism of real-time monitoring pipeline pressure and cavity pressure, the accuracy and reliability of the flow calibration are ensured, and the strict requirements of calibration accuracy and calibration efficiency in advanced semiconductor manufacturing are met. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the present application, the drawings required to be used in the description will be briefly introduced as follows. Obviously, the drawings in the following description are one embodiment of the present application, and other drawings can be obtained by those skilled in the art without creating labor on the basis of these drawings: Figure 1 A structural schematic diagram of a semiconductor device is provided for an embodiment of the present application; Figure 2 A flow chart of a flow calibration method is provided for an embodiment of the present application; Figure 3 A pressure curve diagram of a calibration cavity before filtering is shown, the horizontal axis is time, and the vertical axis is the cavity pressure of the calibration cavity; Figure 4 A pressure curve diagram of a calibration cavity after filtering is shown, the horizontal axis is time, and the vertical axis is the cavity pressure of the calibration cavity; Figure 5 A structural schematic diagram of a flow calibrator is provided for an embodiment of the present application; Figure 6 A pressure change rate curve diagram obtained by directly differentiating the original time domain pressure signal is shown, the horizontal axis is time, and the vertical axis is the pressure change rate; Figure 7 A pressure change rate curve diagram obtained by differentiating the time domain pressure signal after filtering is shown, the horizontal axis is time, and the vertical axis is the pressure change rate. DETAILED DESCRIPTION

[0017] The present application will be further described below in conjunction with the accompanying 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, clearly assisting in explaining the purpose of the embodiments of the present application. In order to make the purpose, features and advantages of the present application more obvious and easy to understand, please refer to the accompanying drawings. It should be noted that the structure, proportion, size and the like shown in the drawings attached to the present specification are only used to cooperate with the content disclosed in the specification, so as to be understood and read by those skilled in the art, and are not used to limit the defined conditions for implementing the present application, therefore, 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 technical content disclosed by the present application.

[0018] In the existing calibration process, after the gas enters the calibration cavity of the flow calibrator at a set flow rate, the pressure sensor continuously collects pressure data in the calibration cavity at a fixed sampling frequency to form a pressure curve, which is often accompanied by significant fluctuations and noise interference, which will affect the accuracy of flow calculation. Due to the poor accuracy of single flow calibration, the calibrator must perform multiple calibrations and take the arithmetic mean value to obtain a relatively reliable calibration result. However, the arithmetic mean value cannot fundamentally filter out the extrinsic interference components, and it is difficult to meet the stringent requirements of calibration accuracy and calibration efficiency in advanced semiconductor manufacturing.

[0019] In view of the above technical problems existing in the prior art, the present application proposes a semiconductor equipment flow calibration method, which converts the time domain pressure signal to the frequency domain pressure signal for selective filtering, effectively separates the real pressure change from various noise interferences, and selects the steady-state section of the pressure change rate curve as the calculation reference, fundamentally avoiding the defects of low efficiency and incomplete noise suppression of the traditional multiple average method, and realizing high-precision and high-efficiency flow calibration.

[0020] Among them, the semiconductor equipment is a semiconductor equipment with flow control function, which can be used to control the gas flow of the equipment cavity in the semiconductor manufacturing process, and the semiconductor equipment includes but is not limited to epitaxial equipment, etching equipment or pre-cleaning equipment.

[0021] As shown in Figure 1 In an embodiment, the semiconductor equipment includes a flow controller 200 (MFC) and a flow calibrator 202 (calibrator) in Figure 1 Figure 1 ​The flow controller 200 is connected with a gas source, and the flow calibrator 202 includes a calibration cavity, one end of the calibration cavity of the flow calibrator is communicated with the flow controller 200 to calibrate the flow controller 200, and the other end of the calibration cavity of the flow calibrator is communicated with the gas inlet end of the device cavity 203.

[0022] As shown in Figure 2 , the flow calibration method includes: S1, setting a target gas flow through the flow controller 200, and delivering gas to the calibration cavity of the flow calibrator 202 at the target gas flow; S2, collecting an original time-domain pressure signal in the calibration cavity at a preset sampling frequency, for reflecting the pressure change in the calibration cavity; As shown in Figure 3 , Figure 3 , the pressure curve of the calibration cavity before filtering processing, Figure 3 the horizontal axis is time, and the vertical axis is the cavity pressure of the calibration cavity, and the pressure curve formed by the original time-domain pressure signal is accompanied by significant fluctuations and noise interference; In order to improve the signal quality and avoid affecting the accuracy of flow calculation, the original time-domain pressure signal is converted into an original frequency-domain pressure signal, and the original frequency-domain pressure signal is filtered to obtain a filtered frequency-domain pressure signal; the filtering processing includes: normalizing the original frequency-domain pressure signal and filtering the high-frequency noise components in the original frequency-domain pressure signal to retain the low-frequency effective components in the original frequency-domain pressure signal; S3, converting the filtered frequency-domain pressure signal into a filtered time-domain pressure signal; As shown in Figure 4 , Figure 4 , the pressure curve of the calibration cavity after filtering processing, Figure 4 the horizontal axis is time, and the vertical axis is the cavity pressure of the calibration cavity, and the pressure curve formed by the converted filtered time-domain pressure signal presents a smooth and continuous characteristic, compared with the pressure curve formed by the original time-domain pressure signal, the fluctuation interference caused by high-frequency noise is effectively eliminated, and a reliable data basis is provided for the accurate calculation of the subsequent pressure change rate; Then, the filtered time-domain pressure signal is differentiated to obtain a pressure derivative signal, and a pressure change rate curve is formed by the pressure derivative signal; S4, extracting the pressure change rate corresponding to the steady stage of the pressure rising stage in the pressure change rate curve as a reference pressure change rate; S5, obtaining the cavity temperature and volume of the calibration cavity, and calculating the measured gas flow according to the reference pressure change rate, the cavity temperature and the volume; S6, comparing the measured gas flow with the target gas flow, and calibrating the flow controller 200 according to the comparison result; for example, adjusting the control parameters or output signals of the flow controller 200 to ensure that the output gas flow is consistent with the target gas flow.

[0023] The present application effectively solves the problem of insufficient calibration accuracy caused by pressure signal fluctuation in the prior art, significantly improves the calibration efficiency, and meets the demand for fast and accurate calibration in modern semiconductor manufacturing.

[0024] Optionally, in the actual implementation of step S5, in order to balance the calibration efficiency and calculation accuracy, the present method includes at least the following two calculation formulas of the measured gas flow according to the stability difference of the temperature in the calibration cavity: The first one is suitable for quasi-isothermal process; when the temperature in the calibration cavity remains constant (the temperature in the calibration cavity remains constant means that the temperature fluctuation in the calibration cavity is controlled within a preset temperature fluctuation threshold, for example, the temperature fluctuation in the calibration cavity is controlled within ±0.5K / min), the measured gas flow is calculated by the following formula: In the formula, Q is the measured gas flow, dP / dt is the reference pressure change rate, V is the volume of the calibration cavity, T is the temperature in the calibration cavity, R is the molar gas constant, and the value of R is 8.314J / (mol·K); The second one is suitable for variable temperature process; when the temperature in the calibration cavity does not remain constant (the temperature in the calibration cavity does not remain constant means that the temperature fluctuation in the calibration cavity is not controlled within a preset temperature fluctuation threshold), the measured gas flow is calculated by the following formula: In the formula, Q is the measured gas flow, dP / dt is the reference pressure change rate, dT / dt is the temperature change rate, V is the volume of the calibration cavity, T is the temperature in the calibration cavity, R is the molar gas constant, and the value of R is 8.314J / (mol·K); The second formula introduces a temperature compensation term under variable temperature conditions, which can reduce the calibration error to meet the stringent calibration requirements of semiconductor-grade flow controllers.

[0025] Optionally, please continue to refer to Figure 1 The flow controller 200 delivers gas to the calibration cavity through a first pipeline, and a first pressure sensor 201 (G0 in Figure 1 ) is arranged on the first pipeline to measure the pipeline pressure of the first pipeline.

[0026] As Figure 5As shown, in one embodiment, the flow calibrator 202 comprises a first upstream valve 100 (V1 valve) in Figure 5 , a second upstream valve 101 (V2 valve) in Figure 5 , a temperature sensor 102 (T1) in Figure 5 , a second pressure sensor 103 (G1) in Figure 5 , a calibration cavity 104, and a downstream valve 105 (V3 valve) in Figure 5 ; The first end of the first upstream valve 100 and the first end of the second upstream valve 101 are both in communication with the flow controller 200, and the second end of the first upstream valve 100 and the second end of the second upstream valve 101 are both in communication with the inlet of the calibration cavity 104; the flow capacity of the first upstream valve 100 is configured to be greater than that of the second upstream valve 101, and the flow controller 200 delivers gas to the calibration cavity 104 through the first upstream valve 100 or the second upstream valve 101; The temperature sensor 102 is used to measure the cavity temperature of the calibration cavity 104, and the second pressure sensor 103 is used to measure the cavity pressure of the calibration cavity 104; The downstream valve 105 is in communication with the outlet of the calibration cavity 104, and is configured to control the opening and closing of the outlet of the calibration cavity 104.

[0027] It should be noted that Figure 5 The structure of the flow calibrator 202 shown is one of the preferred embodiments of the present application. Those skilled in the art can adapt the cavity volume of the calibration cavity 104, the type and number of sensors, and the type, number, and installation position of the control valves according to system pressure rating, flow demand, spatial layout, and other factors without creative effort, and such equivalent variations all fall within the technical concept of the present application.

[0028] Optionally The flow calibration method further comprises closing the downstream valve 105 before delivering gas to the calibration cavity 104; Closing the downstream valve 105 before implementing calibration can ensure the accumulation of gas in the calibration cavity 104; the opening and closing of the downstream valve 105 can be achieved by manual or automatic control, such as control by an electromagnetic valve or a pneumatic valve.

[0029] Optionally The flow calibration method further comprises: Real-time monitoring of the change trend of the pipeline pressure and the cavity pressure, and opening the downstream valve 105 when the pipeline pressure shows an upward trend and / or the cavity pressure stops rising; In the gas calibration process, the pipeline pressure of the first pipeline should be stable in theory after the target gas flow is set by the flow controller 200; if the internal flow resistance of the calibration cavity 104 increases, it will cause abnormal accumulation of gas in the first pipeline, resulting in an upward trend of the pipeline pressure, which indicates that the gas cannot smoothly enter the calibration cavity 104, i.e. there is a flow blockage condition; when the cavity pressure stops rising, it indicates that the gas inflow process in the calibration cavity 104 tends to stop; therefore, when the upward trend of the pipeline pressure and / or the stop of the cavity pressure is monitored, the downstream valve 105 is opened, the gas in the calibration cavity 104 can be released in time, the gas accumulation in the calibration cavity 104 is eliminated, and the accuracy and reliability of the flow calibration are ensured.

[0030] As shown in Figures 6-7 , the application also provides a contrast verification of the influence of the filtering processing on the pressure change rate; wherein Figure 6 the pressure change rate curve obtained by directly deriving the original time-domain pressure signal is shown, the abscissa is time, and the ordinate is the pressure change rate; it can be seen that the pressure change rate curve without filtering processing presents obvious oscillation and noise interference, which leads to a significant reduction in the signal-to-noise ratio, the characteristics of the steady-state section are difficult to identify, and the accuracy of the reference pressure change rate is seriously affected; wherein Figure 7 the pressure change rate curve obtained by deriving the filtered time-domain pressure signal is shown, the abscissa is time, and the ordinate is the pressure change rate; compared with Figure 6 , the filtered pressure change rate curve shows a smooth characteristic, the noise component is effectively suppressed, and the linear characteristics of the steady-state section are clearly identifiable, thereby significantly improving the accuracy of the pressure change rate calculation; The contrast result fully verifies the role of the filtering processing step in eliminating noise interference and ensuring the reliability of subsequent calculation.

[0031] Preferably, to improve the accuracy of the measured gas flow calculation, based on the calculation formula shown above, the accuracy of the reference pressure change rate needs to be ensured, so in the application, the pressure change rate corresponding to the steady-state section of the pressure rise stage of the pressure change rate curve is extracted as the reference pressure change rate; the steady-state section is a continuous section in the pressure rise stage of the pressure change rate curve, the fluctuation amplitude of which continuously remains within the preset tolerance threshold range within the preset time length; the selection of the reference pressure change rate breaks through the limitation of the traditional method of taking the average value multiple times, realizes the accurate locking of the real constant flow characteristic section, and improves the accuracy of the reference pressure change rate in the measured gas flow calculation formula; Specifically, please continue to refer to Figure 7, the pressure rising stage is a section of the pressure change rate curve above the zero point of the longitudinal axis; as Figure 7 As shown in the figure, the pressure rising stage can be divided into three stages in time sequence: a section is a stage of gradually increasing pressure change rate, b section is a stage of relatively stable pressure change rate, and c section is a stage of gradually decreasing pressure change rate; the present application found through in-depth analysis that the b section is selected as the steady state section to extract the reference pressure change rate, effectively eliminating the non-steady state interference information of a section and c section; this selection strategy overcomes the technical bias of technicians who are used to taking the average value of multiple calibrations, and achieves the technical effect that a small amount of calibration process, even once calibration process, can guarantee the calculation accuracy of the measured gas flow, thereby improving the accuracy and efficiency of flow calibration.

[0032] Optionally, the reference pressure change rate is obtained by any of the following ways: selecting the pressure change rate of any point in the steady state section b as the reference pressure change rate, or calculating the average value of the pressure change rates of multiple points in the steady state section b as the reference pressure change rate; wherein, taking the average value of the pressure change rates of multiple points in the steady state section b can further reduce random error and improve the accuracy of the reference pressure change rate.

[0033] Optionally, the high-frequency noise component is the original frequency domain pressure signal with a frequency higher than a preset cutoff frequency, and the low-frequency effective component is the original frequency domain pressure signal with a frequency lower than or equal to the preset cutoff frequency.

[0034] Optionally, the preset cutoff frequency is 1; by reasonably setting the cutoff frequency, the present application can ensure that the high-frequency noise is filtered out while the low-frequency effective signal related to the gas flow is retained.

[0035] Optionally, The flow calibration method comprises the following steps: According to the target gas flow, the volume and the temperature of the calibration cavity 104, a pressure change rate requirement value is calculated, and the pressure change rate requirement value is compared with a preset pressure change rate threshold value; If the pressure change rate requirement value is greater than the preset pressure change rate threshold value, the first upstream valve 100 is used to deliver gas to the calibration cavity; If the pressure change rate requirement value is less than or equal to the preset pressure change rate threshold value, the second upstream valve 101 is used to deliver gas to the calibration cavity; Wherein, the calculation formula of the pressure change rate requirement value is: γ=(F×R×T) / V; wherein γ is a pressure rate of change demand value, F is a target gas flow rate, R is a molar gas constant, T is a temperature inside the calibration chamber 104, and V is a volume of the calibration chamber 104.

[0036] The pre-calculation method of the pressure rate of change demand value is adopted to realize quantitative prediction of the pressure increasing rate during the inflation process. Based on this, the first upstream valve 100 and the second upstream valve 101 are selectively enabled by comparing the pressure rate of change demand value with the preset pressure rate of change threshold value, so as to overcome the technical defects of the single-valve structure, such as insufficient flow resolution caused by the minimum opening limit of the valve at a small flow rate, and too long inflation time caused by the too small valve port diameter at a large flow rate, thereby expanding the effective calibration range and ensuring the accuracy in the full range.

[0037] Each device (parts without specific structure) selected in the present application is a general standard part or a part known to those skilled in the art, the structure and principle of which can be known by the skilled person through a technical manual or through a conventional experimental method. Moreover, the software programs involved in the present application are prior art, and the present application does not involve any improvement on the software programs.

[0038] It should be noted that, in the present text, relational terms such as first and second and the like can only be used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. Moreover, the terms "comprising", "containing" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such a process, method, article or apparatus. Without more limitations, the element defined by the phrase "comprising a" does not exclude the presence of additional identical elements in the process, method, article or apparatus including the element. In addition, the term "connected" in the present text means that A and B are directly connected, or that A and B are indirectly connected, such as A and B being connected through C, even through more components such as C and D, and the connection of A and B can be integral or separate, detachable or fixed. The term "optional" in the present text means that the technical feature can be combined with or not combined with any feature in the present text.

[0039] 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 calibrating the flow rate of a semiconductor device, characterized in that, The semiconductor device includes a flow controller and a flow calibrator. The flow calibrator includes a calibration chamber, which is connected to the flow controller to calibrate the flow controller. The flow calibration method includes: The target gas flow rate is set by the flow controller, and the gas is delivered to the calibration chamber of the flow calibrator at the target gas flow rate. The original time-domain pressure signal in the calibration cavity is acquired at a preset sampling frequency, the original time-domain pressure signal is converted into an original frequency-domain pressure signal, and the original frequency-domain pressure signal is filtered to obtain a filtered frequency-domain pressure signal. The filtered frequency domain pressure signal is converted into a filtered time domain pressure signal, and the pressure derivative signal is obtained by performing a derivative operation on the filtered time domain pressure signal. The pressure rate of change curve is formed from the pressure derivative signal. The pressure change rate corresponding to the steady-state segment of the pressure rise phase in the pressure change rate curve is extracted as the benchmark pressure change rate. The internal temperature and volume of the calibration chamber are obtained, and the measured gas flow rate is calculated based on the reference pressure change rate, the internal temperature, and the volume. The measured gas flow rate is compared with the target gas flow rate, and the flow controller is calibrated based on the comparison results.

2. The semiconductor device flow calibration method as described in claim 1, characterized in that, The filtering process includes: The original frequency domain pressure signal is subjected to normalized low-pass filtering to remove high-frequency noise components and retain the low-frequency effective components.

3. The semiconductor device flow calibration method as described in claim 2, characterized in that, The high-frequency noise component is the original frequency domain pressure signal with a frequency higher than the preset cutoff frequency, and the low-frequency effective component is the original frequency domain pressure signal with a frequency lower than or equal to the preset cutoff frequency.

4. The semiconductor device flow calibration method as described in claim 3, characterized in that, The preset cutoff frequency is 1.

5. The semiconductor device flow calibration method as described in claim 1, characterized in that, The steady-state segment is a continuous section in which the fluctuation amplitude of the pressure change rate curve remains within a preset tolerance threshold range for a preset duration during the pressure rise phase.

6. The semiconductor device flow calibration method as described in claim 1, characterized in that, The reference pressure change rate is obtained in either of the following ways: selecting the pressure change rate at any point within the steady-state range as the reference pressure change rate, or calculating the average of the pressure change rates at multiple points within the steady-state range as the reference pressure change rate.

7. The semiconductor device flow calibration method as described in claim 1, characterized in that, The formula for calculating the measured gas flow rate is: Where Q is the measured gas flow rate, dP / dt is the rate of change of the reference pressure, V is the volume of the calibration chamber, T is the temperature inside the calibration chamber, and R is the molar gas constant, with a value of 8.314 J / (mol·K).

8. The semiconductor device flow calibration method as described in claim 1, characterized in that, The flow calibrator also includes a downstream valve that is connected to the outlet of the calibration chamber and is configured to control the opening and closing of the outlet of the calibration chamber. The flow calibration method further includes closing the downstream valve before supplying gas to the calibration chamber.

9. The semiconductor device flow calibration method as described in claim 8, characterized in that, The flow controller supplies gas to the calibration chamber through a first pipeline, and a first pressure sensor is provided on the first pipeline for measuring the pipeline pressure. The flow calibrator also includes a second pressure sensor for measuring the pressure inside the calibration chamber; The flow calibration method further includes: The downstream valve is opened if the pipeline pressure and the cavity pressure change trend are monitored in real time, and the pipeline pressure shows an upward trend and / or the cavity pressure stops rising.

10. The semiconductor device flow calibration method as described in claim 1, characterized in that, The flow calibrator further includes a first upstream valve and a second upstream valve. The first end of the first upstream valve and the first end of the second upstream valve are both connected to the flow controller, and the second end of the first upstream valve and the second end of the second upstream valve are both connected to the inlet of the calibration chamber. The flow capacity of the first upstream valve is configured to be greater than that of the second upstream valve, and the flow controller supplies gas to the calibration chamber through the first upstream valve or the second upstream valve. The flow calibration method includes supplying gas to the calibration chamber via the flow controller, which comprises: The required pressure change rate is calculated based on the target gas flow rate, the volume of the calibration chamber, and the temperature inside the chamber. The required pressure change rate is then compared with a preset pressure change rate threshold. If the required pressure change rate is determined to be greater than the preset pressure change rate threshold, then gas is supplied to the calibration chamber through the first upstream valve. If the required pressure change rate is less than or equal to the preset pressure change rate threshold, then gas is supplied to the calibration chamber through the second upstream valve; The formula for calculating the required pressure change rate is: γ=(F×R×T) / V; In the formula, γ is the required pressure change rate, F is the target gas flow rate, R is the molar gas constant, T is the temperature inside the calibration chamber, and V is the volume of the calibration chamber.

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