Pressure control system of MOCVD (Metal Organic Chemical Vapor Deposition) reaction cavity and MOCVD epitaxial equipment

Abstract

The invention provides a pressure control system of an MOCVD (Metal Organic Chemical Vapor Deposition) reaction cavity and MOCVD epitaxial equipment, and the system comprises a cavity in which a reaction cavity is defined; the exhaust pipeline is communicated with the reaction cavity; the first pressure gauge is fixed on the cavity body, and the first pressure gauge is used for detecting the gas pressure in the reaction cavity; the exhaust valve is configured to control the exhaust flow through the opening degree of the valve; the vacuum pump is used for extracting gas in the reaction cavity; the mass flow controller is configured to be capable of detecting and controlling the flow of gas flowing into the reaction cavity; and the controller is configured to control the valve opening degree of the exhaust valve and / or control the gas inlet flow of the mass flow controller according to the gas pressure detected by the first pressure meter. According to the pressure control system of the MOCVD reaction chamber, the first pressure meter, the exhaust valve and the mass flow controller are arranged on the chamber body, and the gas pressure can be adjusted in real time, so that the product quality can be effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of pressure control of MOCVD epitaxial equipment, in particular to a pressure control system of an MOCVD reaction chamber and MOCVD equipment. Background Art

[0002] During the thin film growth process using MOCVD epitaxial equipment, the reaction chamber needs to be pressure-tested. In existing solutions, the pressure gauge is generally installed on the exhaust pipe. The pressure gauge obtains the pressure inside the reaction chamber by detecting the pressure of the exhaust pipe. However, there is a difference between the pressure set on the exhaust pipe and the actual pressure inside the reaction chamber, which makes the pressure gauge unable to effectively detect the pressure inside the reaction chamber, thereby reducing product quality. Summary of the Invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a pressure control system for an MOCVD reaction chamber, which can improve product quality.

[0004] The present invention also provides a pressure control system having the MOCVD reaction chamber and an MOCVD epitaxial device having the same.

[0005] According to the first aspect of the present invention, the pressure control system of the MOCVD reaction chamber includes: an exhaust pipeline connected to the reaction chamber; a first pressure gauge, the first pressure gauge is fixed to the chamber body, and the first pressure gauge is used to detect the gas pressure in the reaction chamber; an exhaust valve, the exhaust valve is connected in series to the exhaust pipeline, the exhaust valve is electrically connected to the first pressure gauge, and the exhaust valve is configured to control the exhaust flow rate by valve opening; a vacuum pump, the vacuum pump is connected in series to the exhaust pipeline and is located on the downstream side of the exhaust valve, and the vacuum pump is used to extract gas from the reaction chamber; a mass flow controller, the mass flow controller is fixed to the air inlet pipeline of the chamber body, and the mass flow controller is configured to detect and control the gas flow flowing into the reaction chamber; a controller, the exhaust valve and the mass flow controller are electrically connected to the controller respectively, and the controller is configured to control the valve opening of the exhaust valve and / or control the air inlet flow of the mass flow controller according to the gas pressure detected by the first pressure gauge.

[0006] According to the pressure control system of the MOCVD reaction chamber of the present invention, a first pressure gauge, an exhaust valve and a mass flow controller are arranged on the chamber. The first pressure gauge can accurately detect the gas pressure in the chamber, thereby effectively ensuring the stable growth of the thin film. At the same time, the exhaust valve and the mass flow controller adjust the gas pressure in the reaction chamber in real time, thereby effectively improving product quality.

[0007] According to some embodiments of the present invention, the pressure control system of the MOCVD reaction chamber includes: a connecting pipe, the top wall of the chamber is provided with a through hole extending along the up and down directions, the lower end of the connecting pipe is connected to the circumference of the through hole, the upper end of the connecting pipe extends upward away from the chamber, and the first pressure gauge is connected to the upper end of the connecting pipe.

[0008] According to some embodiments of the present invention, the pressure control system of the MOCVD reaction chamber includes: a controller, wherein the controller pre-stores a pressure target value P set , initial intake flow value Q in and the initial exhaust valve opening value θ, and the first formula is pre-stored: Among them, e(k) is the pressure difference, Δu(k) is the control signal, K p , K i and K d are the preset proportional coefficient, integral coefficient and differential coefficient respectively, T S is a period, k is a time series, the controller is configured to collect the gas pressure detected by the first pressure gauge, and the controller is configured to generate a pressure signal according to the gas pressure P current and the pressure target value P set Calculate the pressure difference e(k).

[0009] According to some optional embodiments of the present invention, the pressure control system of the MOCVD reaction chamber includes: a second pressure gauge, which is arranged on the exhaust pipeline and is used to detect the gas pressure in the exhaust pipeline. The second pressure gauge is electrically connected to the controller.

[0010] According to some optional embodiments of the present invention, the controller is configured to determine whether the exhaust line is blocked based on pressure values ​​detected by the first pressure gauge and the second pressure gauge.

[0011] According to some embodiments of the present invention, the controller is configured to calculate a control signal according to the pressure difference and a pre-stored first formula.

[0012] According to some embodiments of the present invention, the controller is configured to allocate the control amount according to a pre-stored control amount formula: ΔQ in =α·Δu(k), Δθ=-β·Δu(k) to calculate the adjustment amount ΔQ of the mass flow controller in and the adjustment amount Δθ of the exhaust valve, wherein α and β are preset distribution coefficients, and the controller is further configured to calculate the target intake flow rate according to the pre-stored formula: Q in (k) = Q in (k-1)+ΔQ in(k); Get the target intake flow rate Q of the mass flow controller in (k)) and the pre-stored target opening formula: θ(k) = θ(k-1) + Δθ(k) to calculate the target opening θ(k) of the exhaust valve, and the controller controls the mass flow controller to control the valve opening of the exhaust valve to the target opening θ(k).

[0013] According to some embodiments of the present invention, the first pressure gauge is electrically connected to the controller.

[0014] According to some embodiments of the present invention, the exhaust valve includes: a first valve and a second valve connected in series on the exhaust pipe, the first valve is a solenoid valve, and the second valve is a butterfly valve.

[0015] The MOCVD epitaxial growth device according to the second embodiment of the present invention includes the pressure control system of the MOCVD reaction chamber according to the first embodiment of the present application. The MOCVD epitaxial growth device according to the second embodiment of the present invention is provided with the pressure control system of the MOCVD reaction chamber according to the embodiment of the present application, and a first pressure gauge, an exhaust valve, and a mass flow controller are provided on the chamber. The first pressure gauge can accurately detect the gas pressure within the chamber, thereby effectively ensuring the stable growth of the thin film. At the same time, the exhaust valve and the mass flow controller adjust the gas pressure within the reaction chamber in real time, thereby effectively improving product quality.

[0016] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 FIG. 4 is a schematic diagram of a pressure control system of an MOCVD reaction chamber according to an embodiment of the present invention.

[0018] Reference numerals:

[0019] 100. Pressure control system;

[0020] 10. Cavity;

[0021] 21. First pressure gauge; 22. Second pressure gauge;

[0022] 30. Connecting pipe;

[0023] 40. Controller;

[0024] 50. Exhaust pipe;

[0025] 60, exhaust valve; 61, first valve; 62, second valve;

[0026] 70. Vacuum pump;

[0027] 80. Mass flow controller;

[0028] 90. Host computer. DETAILED DESCRIPTION

[0029] The following describes embodiments of the present invention in detail, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and are not to be construed as limiting the present invention.

[0030] Please refer to the following Figure 1 A pressure control system 100 for an MOCVD reaction chamber according to an embodiment of the present invention is described.

[0031] Reference Figure 1 A pressure control system 100 for an MOCVD reaction chamber according to an embodiment of the present invention includes: a chamber 10, an exhaust valve 60, an exhaust line 50, a mass flow controller 80 (MFC), a first pressure gauge 21, a vacuum pump 70, and a controller 40. Specifically, the chamber 10 defines a reaction chamber; the exhaust line 50 communicates with the reaction chamber; the first pressure gauge 21 is fixed to the chamber 10 and is used to detect the gas pressure within the reaction chamber; the exhaust valve 60 is connected in series to the exhaust line 50 and is electrically connected to the first pressure gauge 21. The exhaust valve 60 is configured to control the exhaust flow rate by adjusting the valve opening; the vacuum pump 70 is connected in series to the exhaust line 50 and is located downstream of the exhaust valve 60. The vacuum pump 70 is configured to extract gas from the reaction chamber; and the mass flow controller 80 is fixed to the air inlet line of the chamber 10 and is configured to control the gas flow rate into the reaction chamber based on the gas pressure detected by the first pressure gauge 21.

[0032] Before the reaction begins, evacuating the reaction chamber using a vacuum pump 70 can effectively remove oxygen, moisture, and other impurities in the air that may affect the quality of the film, ensuring a high-purity growth environment. At the same time, the vacuum pump 70 can improve the controllability and stability of the process, thereby ensuring the quality and performance of the final product.

[0033] Optionally, the vacuum pump 70 is a normally open vacuum pump 70, which can work continuously to ensure that the vacuum degree in the system always remains in a stable state. This is especially important for experiments or production processes that require high consistency, such as semiconductor manufacturing, thin film deposition, etc.

[0034] The mass flow controller 80 is fixed to the gas inlet pipeline of the chamber 10 . The mass flow controller 80 is configured to detect and control the gas flow rate flowing into the reaction chamber.

[0035] The exhaust valve 60 and the mass flow controller 80 are electrically connected to the controller 40 respectively. The controller 40 is configured to control the valve opening of the exhaust valve 60 and / or control the intake flow of the mass flow controller 80 according to the gas pressure detected by the first pressure gauge 21.

[0036] When growing a thin film in a reaction chamber, the chemical reactions involved in the thin film growth process are relatively complex, and the type of gas source needs to be continuously switched during the production process. At this time, the first pressure gauge 21 located on the chamber 10 detects the gas pressure in the reaction chamber, and the exhaust valve 60 controls the valve opening size according to the gas pressure detected by the first pressure gauge 21. For example, if the pressure in the reaction chamber is too high, the valve of the exhaust valve 60 is opened to a larger size to facilitate the rapid discharge of the gas from the reaction chamber. Otherwise, the valve of the exhaust valve is reduced to ensure the gas pressure in the reaction chamber. At the same time, the mass flow controller 80 controls the gas flow rate flowing into the reaction chamber according to the gas pressure detected by the first pressure gauge 21. For example, when the gas pressure in the reaction chamber is too high, the gas flow rate flowing into the reaction chamber is reduced. Otherwise, the gas flow rate flowing into the reaction chamber is increased to maintain the pressure balance in the reaction chamber, thereby reducing the pressure fluctuation of the gas pressure in the reaction chamber.

[0037] The pressure control system 100 of the MOCVD reaction chamber of the present invention is provided with a first pressure gauge 21, an exhaust valve 60 and a mass flow controller 80 on the chamber 10. The first pressure gauge 21 can directly detect the pressure in the chamber 10. Compared with the prior art in which the first pressure gauge 21 is provided on the exhaust pipe 50, but the exhaust pipe 50 is inconsistent with the actual pressure in the chamber 10, resulting in an inability to accurately detect the gas pressure in the reaction chamber, the first pressure gauge 21 of the present application directly performs pressure detection on the reaction chamber on the chamber 10, thereby being able to more accurately detect the pressure in the chamber 10. At the same time, during the growth of the semiconductor thin film, even if the type of gas source is continuously switched, the first pressure gauge 21 is close to the reaction chamber, so that the first pressure gauge 21 can still accurately detect the gas pressure in the chamber 10, thereby effectively ensuring the stable growth of the thin film and effectively improving the product quality. The exhaust valve 60 is configured to control the degree of valve opening based on the gas pressure detected by the first pressure gauge. The mass flow controller 80 is configured to control the flow of gas into the reaction chamber based on the gas pressure detected by the first pressure gauge. The exhaust valve 60 and the mass flow controller 80 adjust the gas pressure within the reaction chamber in real time based on the gas pressure detected by the first pressure gauge 21, thereby maintaining the stability of the gas pressure within the reaction chamber and effectively ensuring product quality.

[0038] According to the pressure control system 100 of the MOCVD reaction chamber of an embodiment of the present invention, a first pressure gauge 21, an exhaust valve 60 and a mass flow controller 80 are provided on the chamber 10. The first pressure gauge 21 can accurately detect the gas pressure in the chamber 10, thereby effectively ensuring the stable growth of the thin film. At the same time, the exhaust valve 60 and the mass flow controller 80 adjust the gas pressure in the reaction chamber in real time, thereby effectively improving product quality.

[0039] According to some embodiments of the present invention, referring to Figure 1 The pressure control system 100 of the MOCVD reaction chamber includes: a connecting pipe 30, a through hole penetrating in the top wall of the chamber 10, and a lower end of the connecting pipe 30 (such as Figure 1 The lower end of the connecting pipe 30 shown in FIG. 3 is connected to the periphery of the through hole, and the upper end of the connecting pipe 30 (as shown in FIG. Figure 1 The upper end of the connecting pipe 30 shown in FIG. 1 extends upward away from the cavity 10 , and the first pressure gauge 21 is connected to the upper end of the connecting pipe 30 .

[0040] Since the reaction chamber of the cavity 10 is a high-temperature environment, the first pressure gauge 21 cannot be installed in the reaction chamber. Therefore, the first pressure gauge 21 is installed on the connecting pipe 30 connected to the reaction chamber, which can not only protect the first pressure gauge 21 but also ensure that the first pressure gauge 21 functions normally. At the same time, the first pressure gauge 21 is located at the top of the reaction chamber. The first pressure gauge 21 can monitor the pressure changes in the reaction chamber in real time, and the pressure value detected by the first pressure gauge 21 is the actual pressure of the reaction chamber. There is no need to compensate or correct the pressure of the reaction chamber subsequently, thereby effectively improving the pressure control accuracy of the MOCVD reaction chamber.

[0041] For example, Figure 1 As shown, the connecting pipe 30 extends in the up-down direction, the lower end of the connecting pipe 30 is connected to the through hole, and the first pressure gauge 21 is provided at the upper end of the connecting pipe 30 .

[0042] According to some embodiments of the present invention, referring to Figure 1 The pressure control system 100 of the MOCVD reaction chamber includes: a controller 40, which pre-stores a pressure target value P set , initial intake flow value Q in and the initial exhaust valve opening value θ, and the first formula is pre-stored: Among them, e(k) is the pressure difference, Δu(k) is the control signal, K p , K i and K d are the preset proportional coefficient, integral coefficient and differential coefficient respectively, T SThe controller 40 is configured to collect the gas pressure detected by the first pressure gauge 21 and to generate a time series according to the gas pressure P. current and the pressure target value P set Calculate the pressure difference e(k).

[0043] Thus, the controller 40 receives the signal from the first pressure gauge 21, eliminating the need for manual readings and improving work efficiency. Furthermore, the controller 40 directly controls the pressure within the reaction chamber, effectively increasing control speed. In some embodiments, the first pressure gauge 21 is electrically connected to the controller 40 to implement an interlocking function. Specifically, when the pressure exceeds a limit, the controller 40 can stop the operation of certain components of the reaction chamber, such as stopping air intake, stopping the rotation of the susceptor, carrier plate, and wafer, etc.

[0044] According to some optional embodiments of the present invention, referring to Figure 1 The pressure control system 100 for the MOCVD reaction chamber includes a second pressure gauge 22 , which is disposed on the exhaust line 50 and is used to detect the gas pressure within the exhaust line 50 . The second pressure gauge 22 is electrically connected to the controller 40 . Thus, the second pressure gauge 22 detects the gas pressure in the exhaust line 50 , and the values ​​of the second pressure gauge 22 and the first pressure gauge 21 are compared to ensure the accuracy of the detected gas pressure within the reaction chamber.

[0045] According to some embodiments of the present invention, referring to Figure 1 Controller 40 is configured to determine whether exhaust line 50 is clogged based on the pressure values ​​detected by first pressure gauge 21 and second pressure gauge 22. This allows technicians to take timely preventive measures, effectively improving equipment stability and ensuring the quality of thin film growth. For example, if the values ​​of first pressure gauge 21 and second pressure gauge 22 are relatively close, it indicates that exhaust line 50 is not clogged. If the value of second pressure gauge 22 is much greater than that of first pressure gauge 21, it indicates that exhaust line 50 is clogged and needs to be cleaned.

[0046] According to some optional embodiments of the present invention, referring to Figure 1 The first pressure gauge 21 is a thin film pressure gauge, and / or the second pressure gauge 22 is a thin film pressure gauge. Thus, the thin film pressure gauge can detect very subtle pressure changes, so that the first pressure gauge 21 and / or the second pressure gauge 22 can accurately detect subtle changes in gas pressure.

[0047] According to some optional embodiments of the present invention, referring to Figure 1Controller 40 is configured to calculate a control signal based on the pressure difference and a pre-stored first formula. Thus, directly generating a control signal from the pressure difference using the pre-stored formula avoids complex iterations or search processes and is suitable for systems requiring fast response, particularly air pressure regulation, thereby ensuring accuracy in controlling the pressure difference by controller 40.

[0048] According to some optional embodiments of the present invention, referring to Figure 1 , the controller 40 is configured to allocate the control quantity according to the pre-stored control quantity formula: ΔQ in =α·Δu(k), Δθ=-β·Δu(k) to calculate the adjustment amount ΔQ of the mass flow controller in and the adjustment amount Δθ of the exhaust valve, where α and β are preset distribution coefficients, and are further configured as follows: the controller 40 is further configured according to the pre-stored target intake flow formula: Q in (k) = Q in (k-1)+ΔQ in (k); Get the target intake flow rate Q of the mass flow controller 80 in (k)) and the pre-stored target opening formula: θ(k) = θ(k-1) + Δθ(k) to calculate the target opening θ(k) of the exhaust valve, and the controller 40 controls the mass flow controller 80 and controls the valve opening of the exhaust valve 60 to be the target opening θ(k).

[0049] In this way, the difference between the gas pressure and the target pressure value is calculated using the first formula, thereby ensuring the accuracy of the controller 40 in controlling the pressure in the reaction chamber, thereby effectively ensuring product quality.

[0050] According to some optional embodiments of the present invention, referring to Figure 1 The first pressure gauge 21 is electrically connected to the controller 40. Thus, the controller 40 can receive the pressure signal of the first pressure gauge 21, and thus can calculate the pressure difference in the reaction chamber according to the pressure signal of the first pressure gauge 21.

[0051] According to some embodiments of the present invention, referring to Figure 1 The exhaust valve 60 includes a first valve 61 and a second valve 62 connected in series to the exhaust line 50. The first valve 61 is a solenoid valve, and the second valve 62 is a butterfly valve. Thus, the solenoid valve controls the opening and closing of the exhaust line 50. After production is completed, the solenoid valve can be closed to prevent insects, debris, water vapor, and other objects from entering the reaction chamber through the exhaust line 50. The butterfly valve also controls the flow cross-section of the exhaust line 50, allowing the controller 40 to adjust the opening angle of the butterfly valve according to actual needs, thereby accurately controlling the gas pressure within the reaction chamber.

[0052] Optionally, the first valve 61 is a normally open solenoid valve, which remains open when no power is supplied. This means that during normal operation, no continuous power supply is required to keep the valve open, which helps to reduce energy consumption and is particularly suitable for application scenarios that need to remain open for a long time.

[0053] For example, Figure 1 As shown, the first valve 61, the second valve 62, the second pressure gauge 22 and the vacuum pump 70 are sequentially arranged on the exhaust pipe 50. The gas in the reaction chamber can flow out of the exhaust pipe 50 through the first valve 61, the second valve 62, the second pressure gauge 22 and the vacuum pump 70 in sequence, thereby effectively avoiding excessive pressure in the reaction chamber and affecting the quality of thin film growth.

[0054] According to some embodiments of the present invention, the exhaust valve 60 includes a control unit. For example, the second valve 62 is an intelligent electric butterfly valve with a control function. The second valve 62 is electrically connected to the first pressure gauge 21. The exhaust valve 60 can automatically control the valve opening according to the pressure difference. Further, the second valve 62 can automatically control the valve opening according to the pressure difference.

[0055] Furthermore, if Figure 1 As shown, the controller 40 includes: a signal processing unit, a pressure difference analysis unit and an execution unit. The signal processing unit is used to receive signals from the first pressure gauge 21, the second pressure gauge 22, the mass flow controller 80, the first valve 61 and the vacuum pump 70. The pressure difference analysis unit is used to analyze the pressure signals of the first pressure gauge 21 and the second pressure gauge 22. After the pressure analysis, the execution unit is used to control the opening size of the second valve 62, thereby adjusting the pressure in the reaction chamber, thereby ensuring the growth quality of the thin film.

[0056] Furthermore, if Figure 1 As shown, the pressure control system 100 of the MOCVD reaction chamber includes: a host computer 90, which is electrically connected to the controller 40. The operator can directly operate the host computer 90 to control the controller 40, thereby facilitating the operator's control of the pressure control system 100 of the MOCVD reaction chamber.

[0057] The MOCVD epitaxial device according to the second embodiment of the present invention includes the pressure control system 100 of the MOCVD reaction chamber according to the first embodiment of the present application.

[0058] According to the MOCVD epitaxial device of the second embodiment of the present invention, by setting the pressure control system 100 of the MOCVD reaction chamber according to the embodiment of the present application, a first pressure gauge 21, an exhaust valve 60 and a mass flow controller 80 are set on the chamber 10. The first pressure gauge 21 can accurately detect the gas pressure in the chamber, thereby effectively ensuring the stable growth of the thin film. At the same time, the exhaust valve 60 and the mass flow controller 80 adjust the gas pressure in the reaction chamber in real time, thereby effectively improving product quality.

[0059] Furthermore, if Figure 1 As shown, the control method of the pressure control system 100 of the MOCVD reaction chamber is as follows:

[0060] Step 1: The controller 40 of the pressure control system 100 of the MOCVD reaction chamber is preset with the target pressure P of the reaction chamber. set At this time, the mass flow controller 80, the first valve 61 and the second valve 62 are all open, and the gas enters the reaction chamber. The first pressure gauge 21 detects the gas pressure in the reaction chamber at predetermined intervals and transmits it to the second valve 62. The second valve 62 calculates the pressure difference between the detected gas pressure and the target pressure and transmits the pressure difference to the controller 40.

[0061] Furthermore, the predetermined time is 5ms, 10ms, 15ms, etc.

[0062] In step 2, the controller 40 calculates the control signal according to the pressure difference and the pre-stored first formula: Among them, e(k) is the pressure difference, Δu(k) is the control signal, K p , K i and K d are the preset proportional coefficient, integral coefficient and differential coefficient respectively, T S is the period, for example 0.1 seconds, and k is the time series.

[0063] Step 3: The controller 40 allocates the control quantity according to the pre-stored control quantity formula: ΔQ in =α·Δu(t), Δθ=-β·Δu(t) to calculate the adjustment amount ΔQ of the mass flow controller 80 in And the adjustment amount Δθ of the exhaust valve 60, where α and β are the preset distribution coefficients (need to be calibrated), and the negative sign indicates that the opening of the exhaust valve 60 is adjusted inversely with the pressure, and then according to the pre-stored target intake flow formula: Q in (k) = Q in (k-1)+ΔQ in (k); Get the target intake flow rate Q of the mass flow controller 80 in(k)) and the pre-stored target opening formula: θ(k) = θ(k-1) + Δθ(k) to calculate the target opening θ(k) of the exhaust valve 60, and the controller 40 controls the mass flow controller 80 to control the valve opening of the exhaust valve 60 to be the target opening θ(k), that is, to exhaust gas at the target opening.

[0064] Step 4: Detect the pressure within the reaction chamber and determine whether the comparison value obtained based on the actual pressure and the target pressure is within a preset threshold range. If so, the process ends; otherwise, the process repeats until step 3. Specifically, the actual pressure within the reaction chamber is first detected by the first pressure gauge 21. The first pressure gauge 21 transmits the actual pressure to the exhaust valve 60, which then transmits the pressure to the controller 40. The controller 40 is preset with a target pressure and a threshold range. The threshold range can be a specific value or percentage, but is not limited to this. For example, ±0.1 mbar, or a ratio of the actual pressure to the target pressure of 99.9%-100.1%, etc. Taking a threshold range of ±0.1 mbar as an example, the controller 40 calculates the difference between the target pressure and the actual pressure, uses this difference as a comparison value, and determines whether the comparison value is within the threshold range. If so, the process ends; otherwise, the process repeats steps 1 to 3.

[0065] If the comparison value obtained based on the actual pressure and the target pressure is within the preset threshold range, it means that the pressure in the reaction chamber has reached a stable state, meets the process requirements, and can enter the thin film deposition process.

[0066] In some embodiments, step 1 further includes the first pressure gauge 21 detecting the actual pressure in the reaction chamber at predetermined intervals, and the first pressure gauge 21 performs filtering correction on the actual pressure, for example, using a three-stage filter, and the formula is: P filter (k)=0.7Pcurrent(k)+0.2Pcurrent(k-1)+0.1Pcurrent(k-2), and the corrected actual pressure is transmitted to the exhaust valve 60 and then transmitted to the controller 40.

[0067] In some embodiments, the controller 40 is preset with a control signal limiter, for example, the control signal limiter is 10%. When the control signal Δu(k) exceeds the control signal limiter, the control signal limiter is used as the control signal Δu(k).

[0068] In some embodiments, in step 3, the controller 40 calculates the target opening θ(k) and first performs nonlinear compensation on the butterfly valve. The nonlinear compensation formula is: θ(k) = [θ(t-1) 1.8 +Δθ] 1 / 1.8 , the controller 40 controls the exhaust valve 60 to exhaust according to the compensated target opening θ(k).

[0069] The following is a specific example to illustrate:

[0070] Initial state:

[0071] The target pressure set by the controller 40 is Pset=100 mbar;

[0072] The current pressure of the reaction chamber Pcurrent = 80 mbar;

[0073] Current mass flow controller 80 flow Q in =200sccm;

[0074] K p =2.2, K p =0.04, K p =0.5;

[0075] α=0.12,β=0.15; where the target pressure P set , α, β are all preset in the controller 40.

[0076] The calculation and control of pressure control are as follows:

[0077] First, the controller 40 performs an error calculation: e(1)=100-79.8=20.2 mbar (assuming the actual pressure after filtering by the first pressure gauge 21 is 79.8 mbar);

[0078] Next, the controller 40 calculates the control signal:

[0079] Because it exceeds the control signal limit, the control signal limit is used as the control signal, and the control signal is 10% at this time;

[0080] Then, the controller 40 calculates the target flow rate of the first sequence MFC and the target opening of the butterfly valve:

[0081]

[0082] Δθ(1)=-0.15×10=-1.5%,

[0083] Then perform nonlinear compensation of butterfly valve: θ(1)=[35 1.8 +(-1.5)] 1 / 1.8 =34.1%;

[0084] Finally, determine whether the actual pressure is within the threshold range:

[0085] Assuming the threshold range is ±0.1 mbar and the target pressure is 100 mbar, the actual pressure detected by the first pressure gauge 21 is 81.5 mbar (filtered and corrected). The difference between the target pressure and the actual pressure is 100 - 81.5 = 18.5 mbar. Since 18.5 mbar > 0.1 mbar, the actual pressure is outside the threshold range and does not meet the requirement. The above steps are repeated until the actual pressure is within the threshold range. In this example, the above steps are repeated 81 times to reach a stable state.

[0086] The time series 0-80 corresponds to 0 to 8 seconds. Some calculation results can be found in Table 1 below. The specific calculation steps and control process will not be described in detail.

[0087] Table 1 Pressure control calculation results

[0088]

[0089] In some embodiments, the controller 40 is further provided with a mass flow controller 80 flow limit and an exhaust valve 60 opening limit, wherein the exhaust valve 60 opening is between 0% and 100%, and the MFC flow is limited to a preset minimum flow Q min With the maximum flow Q max between.

[0090] In some embodiments, the distribution coefficients α (MFC flow rate adjustment weight) and β (exhaust valve 60 opening adjustment weight) in the MOCVD reactor pressure control system 100 are calibrated through experimental testing and dynamic characteristics analysis. The following are specific calibration steps and examples:

[0091] Step S101: Independently test the gain coefficients of the MFC and the exhaust valve 60. Specifically, the following steps are included:

[0092] Test the gain coefficient K of MFC MFC : The opening of the exhaust valve 60 is fixed (eg, 50%), and a step flow change (eg, an increase of 10 sccm) is applied to the mass flow controller 80.

[0093] Record the pressure change rate ΔP / Δt and calculate the gain: Test the gain coefficient K of the exhaust valve 60 Valve :

[0094] The flow rate of the mass flow controller 80 is fixed, and a step opening change (e.g., a 5% decrease) is applied to the exhaust valve 60;

[0095] Record the pressure change rate and calculate the gain:

[0096] Step S102: Determine the distribution coefficient ratio.

[0097] Assign weights according to the gain ratio to balance the regulatory effects of the two:

[0098]

[0099] Example:

[0100] K MFC =0.2Pa / s per sccm,

[0101] The proportional relationship is:

[0102] Step S103: Normalize and determine the absolute value.

[0103] Set the total control strength (e.g. total weight is 1):

[0104]

[0105] Substituting the proportional relationship and solving the equation, we can get the specific values ​​of α and β.

[0106] It should be noted that, in the above-mentioned method for controlling the pressure of the reaction chamber, the exhaust valve 60 generally refers to the second valve 62 , and the second valve 62 is a butterfly valve.

[0107] In some embodiments of the present invention, a MOCVD epitaxial device is further provided, which includes the pressure control system 100 of the reaction chamber of any of the above embodiments.

[0108] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0109] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature identified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0110] In the present invention, unless otherwise expressly specified or limited, terms such as "mounted," "connected," "connect," and "fixed" should be understood broadly. For example, they may refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection, or communication; direct connection or indirect connection through an intermediate medium; and internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0111] In the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0112] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the claims and their equivalents.

Claims

1. A pressure control system (100) for an MOCVD reaction chamber, characterized in that: include: a cavity (10), wherein a reaction chamber is defined within the cavity (10); an exhaust pipe (50) connected to the reaction chamber; a first pressure gauge (21), the first pressure gauge (21) being fixed to the chamber (10), the first pressure gauge (21) being used to detect the gas pressure in the reaction chamber; an exhaust valve (60), the exhaust valve (60) being serially connected to the exhaust pipeline (50), the exhaust valve (60) being electrically connected to the first pressure gauge (21), and the exhaust valve (60) being configured to control the exhaust flow rate by means of a valve opening; a vacuum pump (70), the vacuum pump (70) being serially connected to the exhaust pipeline (50) and located downstream of the exhaust valve (60), the vacuum pump (70) being used to extract gas from the reaction chamber; a mass flow controller (80), the mass flow controller (80) being fixed to the gas inlet pipeline of the chamber (10), the mass flow controller (80) being configured to detect and control the gas flow rate flowing into the reaction chamber; The controller (40) is electrically connected to the exhaust valve (60) and the mass flow controller (80), respectively. The controller (40) is configured to control the valve opening of the exhaust valve (60) and / or control the intake flow of the mass flow controller (80) according to the gas pressure detected by the first pressure gauge (21).

2. The pressure control system (100) of the MOCVD reaction chamber according to claim 1, characterized in that: include: A connecting tube (30), wherein the top wall of the cavity (10) is provided with a through hole penetrating in the up-down direction, the lower end of the connecting tube (30) is connected to the periphery of the through hole, the upper end of the connecting tube (30) extends upward away from the cavity (10), and the first pressure gauge (21) is connected to the upper end of the connecting tube (30).

3. The pressure control system (100) of the MOCVD reaction chamber according to claim 1, characterized in that: include: The controller (40) has a pre-stored pressure target value P set , initial intake flow value Q in and the initial exhaust valve opening value θ, and the first formula is pre-stored: Among them, e(k) is the pressure difference, Δu(k) is the control signal, K p , K i and K d are the preset proportional coefficient, integral coefficient and differential coefficient respectively, T S is a period, k is a time series, the controller (40) is configured to collect the gas pressure detected by the first pressure gauge (21), and the controller (40) is configured to current and the pressure target value P set Calculate the pressure difference e(k).

4. The pressure control system (100) of the MOCVD reaction chamber according to claim 3, characterized in that: include: A second pressure gauge (22) is provided on the exhaust pipe (50) and is used to detect the gas pressure in the exhaust pipe (50). The second pressure gauge (22) is electrically connected to the controller (40).

5. The pressure control system (100) of the MOCVD reaction chamber according to claim 4, characterized in that: The controller (40) is configured to determine whether the exhaust pipe (50) is blocked based on the pressure values ​​detected by the first pressure gauge (21) and the second pressure gauge (22).

6. The pressure control system (100) of the MOCVD reaction chamber according to claim 4, characterized in that: The controller (40) is configured to calculate a control signal according to the pressure difference and a pre-stored first formula.

7. The pressure control system (100) of the MOCVD reaction chamber according to claim 4, characterized in that: The controller (40) is configured to allocate the control quantity according to the pre-stored control quantity formula: ΔQ in =α·Δu(k), Δθ=-β·Δu(k) The adjustment amount ΔQ of the mass flow controller (80) is calculated in and the adjustment amount Δθ of the exhaust valve (60), wherein α and β are preset distribution coefficients, and the controller (40) is further configured to adjust the target intake flow rate according to the pre-stored target intake flow rate formula: Q in (k) = Q in (k-1)+ΔQ in (k); obtain the target intake flow rate Q of the mass flow controller (80) in (k)) and a pre-stored target opening formula: θ(k)=θ(k-1)+Δθ(k) to calculate the target opening θ(k) of the exhaust valve (60), and the controller (40) controls the mass flow controller (80) to control the valve opening of the exhaust valve (60) to be the target opening θ(k).

8. The pressure control system (100) of the MOCVD reaction chamber according to claim 4, characterized in that: The first pressure gauge (21) is electrically connected to the controller (40).

9. The pressure control system (100) of the MOCVD reaction chamber according to claim 1, characterized in that: The exhaust valve (60) comprises a first valve (61) and a second valve (62) connected in series to the exhaust pipeline (50), wherein the first valve (61) is a solenoid valve and the second valve (62) is a butterfly valve.

10. A MOCVD epitaxial device, characterized in that: A pressure control system (100) comprising the MOCVD reaction chamber according to any one of claims 1 to 9.

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