Method for correcting internal and external temperatures of tubular furnace and tubular furnace with temperature correction function

Abstract

The invention provides a tubular furnace internal and external temperature correction method and a tubular furnace with a temperature correction function, a series of corresponding values of real-time measured values T < inner > of an in-tube temperature measuring device and real-time measured values T < outer > of an out-tube temperature measuring device are collected, and a statistical analysis or machine learning algorithm is applied to generate a plurality of sections of fitting lines describing the relationship between the T < inner > and the T < outer >. In the use process, the temperature of the reaction area of the tube furnace is corrected by using the measured value and the fitting line of the temperature measuring device outside the tube, so that the measurement deviation caused by the fact that the temperature measuring device is arranged outside the tube furnace is avoided, and the accurate measurement and control of the temperature in the tube furnace are realized.

Description

Technical Field

[0001] The invention relates to the technical field of high-temperature sintering, and in particular to a method for correcting the internal and external temperatures of a tubular furnace and a tubular furnace with a temperature correction function. Background Art

[0002] In chemical synthesis, material science and other related fields, precise control of the internal temperature of the reactor is essential to achieve high-quality products. Tube furnaces, as a commonly used high-temperature heating equipment, play an important role in industrial production and scientific research.

[0003] The temperature control method of a traditional tube furnace is usually to install one or more thermocouples in the furnace to monitor the actual temperature in the furnace and transmit the signal to the temperature controller, which automatically adjusts the power of the heating element through a feedback loop.

[0004] Tube furnace is a commonly used device for chemical vapor deposition. In the process of chemical vapor deposition, the deposition temperature has a decisive influence on the growth rate, crystal structure, purity and final performance of the film. In order to accurately measure and control the temperature, the temperature measuring device needs to be as close to the reaction zone as possible. However, in the process of chemical vapor deposition to form thin films, gaseous substances produce chemical reactions and transmission reactions on the substrate to form thin films. Thermocouples are usually made of metals or alloys. If the thermocouples are exposed, the metal materials will be vaporized or react with the gaseous substances in the reaction environment, thereby affecting the accuracy of the measurement and even contaminating the deposited film.

[0005] In the prior art, some vapor deposition devices place thermocouples outside the quartz tube and close to the quartz tube to measure the temperature outside the reaction zone. However, in actual applications, the temperature difference between the outside temperature and the reaction zone is large, and this setting cannot accurately control the temperature in the reaction zone.

[0006] Therefore, it is urgent to improve the accuracy of temperature measurement in a tube furnace used for chemical vapor deposition. Summary of the invention

[0007] The purpose of the present invention is to solve the problem of inaccurate temperature measurement in a tube furnace reaction zone and inability to accurately control the temperature in the tube furnace reaction zone.

[0008] In a tubular furnace used for chemical vapor deposition reactions, in order to ensure the quality of the deposited film, a thermocouple is placed outside the furnace tube, resulting in a large difference between the temperature measured by the thermocouple and the temperature of the actual reaction zone.

[0009] In a first aspect, the present invention provides a method for calibrating the internal and external temperatures of a tube furnace, which specifically comprises the following steps: Data collection stage: No reactants are placed in the tube furnace. After heating, a series of real-time measurement values ​​T of the temperature measuring device in the tube are collected.内 The real-time measurement value T of the temperature measuring device outside the tube 外 The corresponding value of Fitting line generation stage: Divide the temperature range, perform segmented fitting based on the collected data, and use statistical analysis or machine learning algorithms to generate multiple segments describing T 内 With T 外 The fitted line of the relationship between Data correction stage: During use, the real-time temperature of the reaction zone in the tubular furnace is obtained through the measurement value and fitting line of the temperature measuring device outside the tube.

[0010] Furthermore, the data collection stage includes selecting a large temperature measurement interval T of the tube furnace 最小 ~T 最大 , record the data every time the temperature rises △T; Preferably, T 最小 At 50°C, T 最大 1000℃; Preferably, ΔT is less than or equal to 50°C.

[0011] Furthermore, the fitting line generation stage includes the following steps: With time as the X-axis and temperature as the Y-axis, draw a graph of T based on the collected data. 外 and T 内 Difference map; According to T 外 and T 内 Difference map, divide the temperature into small intervals; According to the determined temperature interval, the original data set is divided into a corresponding number of subsets, each of which contains the T 内 With T 外 The corresponding value of T is obtained by performing linear regression analysis on each subset, with the goal of finding the linear function, T 内 =m×T 外 +b, where m is the slope and b is the intercept; Plot the obtained fitting straight line on the scatter plot of the original data to visually check the fitting effect of the model; Preferably, it is divided into three temperature intervals, T 外 ≤350℃ range, 350℃<T 外 ≤700℃ range, 700℃<T 外 ≤1000℃ range; Preferably, the fitting line between the three temperature zones is, T 外 ≤350℃ range, T 内 =m1×T 外 +b1, m1=0.9101, b1=-12.729; 350℃<T 外 ≤700℃ range, T 内 =m2×T 外 +b2, m2=1.0326, b2=-55.886; 700℃<T 外 ≤1000℃ range, T 内 =m3×T 外 +b3, m3=1.3396, b3=-274.02.

[0012] Furthermore, the data correction stage includes: the real-time measurement value T of the temperature measuring device outside the tube 外 The temperature is transmitted to the control system, which calculates and corrects the real-time temperature T of the reaction zone in the tube furnace through fitting line calculation. 内 .

[0013] Further, the data correction stage includes: the temperature required for the reaction in the reaction zone of the tube furnace is used as the preset target temperature T 预设 , set the preset target temperature T 预设 The temperature is transmitted to the control system, and the control system calculates and corrects the reaction zone in the tube furnace to reach the preset target temperature T through fitting line calculation. 预设 The real-time measurement value T of the temperature measuring device outside the tube 外 , that is, the heating temperature T that the heating device needs to reach 加热装置 .

[0014] In a second aspect, the present invention further proposes a method for accurately obtaining the reaction temperature in a tube furnace, which comprises: using the correction method described in the first aspect to obtain the reaction temperature in the tube furnace.

[0015] In a third aspect, the present invention also proposes a method for accurately controlling the heating temperature of a tube furnace, comprising: setting a preset target temperature T in the control system of the tube furnace; 预设 , the correction method described in the first aspect is used to obtain the heating temperature T that the heating device needs to reach 加热装置 ; The control system obtains the real-time measurement value T of the temperature measuring device outside the tube 外 The heating temperature T required by the heating device 加热装置 Compare and control the real-time measurement value T of the temperature measuring device outside the tube 外 The heating temperature T that the heating device needs to reach 加热装置 .

[0016] The reaction temperature is usually based on empirical temperature, but for different substrates and different deposition materials, precise control cannot be achieved using only empirical parameters. In order to obtain two-dimensional materials and solve the problem that in the chemical deposition process of preparing thin films, only empirical parameters are often used to fail to obtain products that meet the requirements, the present invention proposes the use of a visual tube furnace in combination with an in-situ observation device.

[0017] In a fourth aspect, the present invention further proposes a method for accurately obtaining the reaction temperature in a visualized tube furnace, comprising: Obtaining a fitting line function relationship according to the correction method of the first aspect; The empirical temperature required for the reaction in the reaction zone of the tube furnace is used as the preset target temperature T 预设 , set the preset target temperature T 预设 The control system calculates and corrects the reaction zone in the tube furnace to reach the preset target temperature T through the fitting line calculation. 预设 The real-time measurement value T of the temperature measuring device outside the tube 外 ; The control system calculates the heating temperature T that the heating device needs to reach according to the preset calculation model 加热装置阈值 , and feed it back to the heating device. The preset calculation model here is to ensure that the reaction temperature in the reaction zone of the tube furnace is not less than the actual required reaction temperature; Control the heating device and determine each node of the reaction through the visualization window; The control system uses the fitting line to convert the real-time measurement value T 外 Corrected to the real-time temperature T of the reaction zone in the tube furnace 内 , that is, the actual reaction temperature.

[0018] Furthermore, in step (2), the preset calculation model is T 加热装置阈值 =T 外 +50℃.

[0019] Furthermore, each reaction node in step (3) includes one or more of: melting of powder raw material, formation of thin film, etching of thin film and change of thin film shape.

[0020] In the fifth aspect, the present invention also proposes a tubular furnace with a temperature correction function, which includes a furnace tube, a heating device, a control system, and a temperature measuring device outside the tube; the control system includes a correction module, which directly displays the real-time temperature of the reaction zone in the tubular furnace by correcting the temperature.

[0021] Furthermore, the correction module stores the fitting line obtained by adopting the correction method of the first aspect.

[0022] Furthermore, a preset target temperature T is set in a preset temperature zone of the control system. 预设 , set the preset target temperature T 预设 The control system calculates and corrects the reaction zone in the tube furnace to reach the preset target temperature T through the fitting line calculation. 预设 The real-time measurement value T of the temperature measuring device outside the tube 外 , control the heating temperature T that the heating device needs to reach 加热装置 Equal to the real-time measurement value T of the temperature measuring device outside the tube外 .

[0023] If the preset target temperature T 预设 is the empirical temperature. Furthermore, the correction module also stores a preset calculation model, and the control system calculates the heating temperature T required to be reached by the heating device according to the preset calculation model. 加热装置阈值 , and feed it back to the heating device. The preset calculation model here is to ensure that the reaction temperature in the reaction zone of the tubular furnace is not less than the actual required reaction temperature.

[0024] Preferably, the preset calculation model is: 加热装置阈值 =T 外 +50℃.

[0025] Furthermore, the control system includes a feedback adjustment module, and the control system obtains the real-time measurement value T of the external temperature measuring device 外 The heating temperature T required by the heating device 加热装置 or T 加热装置阈值 Compare and control the real-time measurement value T of the temperature measuring device outside the tube 外 The heating temperature T that the heating device needs to reach 加热装置 or T 加热装置阈值 .

[0026] Preferably, if the real-time measurement value T of the temperature measuring device outside the tube is 外 Lower than the heating temperature T required by the heating device 加热装置 or T 加热装置阈值 , the control system drives the heating device to increase the temperature for heating; if the real-time measurement value T 外 Equal to the heating temperature T that the heating device needs to reach 加热装置 or T 加热装置阈值 , the control module drives the heating device to maintain the temperature.

[0027] The beneficial effects of the present invention are: (1) In the present invention, the temperature of the reaction zone of the tubular furnace is corrected by fitting the line, thereby avoiding the measurement deviation caused by the temperature measuring device being arranged outside the furnace tube; the temperature correction method of the present invention can realize the accurate measurement and control of the temperature inside the tubular furnace tube; (2) The calibration method of the present invention is used for in-situ observation of a visualized tube furnace for chemical deposition reactions, and can accurately obtain the actual temperature of each reaction node, thus avoiding inaccurate empirical temperature. (3) The tubular furnace with temperature correction function of the present invention can realize accurate measurement and control of the temperature of the tubular furnace and is easy to operate. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Diagram of the device used for temperature correction; Figure 2 Tube outer temperature T 外 and the temperature inside the tube T 内 Difference map; Figure 3 The temperature fitting line of the range less than 350℃; Figure 4 Temperature fitting line in the range of 350℃-700℃; Figure 5 Temperature fitting line in the range of 700℃-1000℃. DETAILED DESCRIPTION

[0029] The device used in the present invention is a tube furnace, such as Figure 1 , specifically including: a furnace tube 1, a heating device 2, an external temperature measuring device 3, an internal temperature measuring device 4 and a control system.

[0030] Example 1: Method for Correcting the Temperature of the Reaction Zone in a Tubular Furnace Data collection stage: the temperature measuring device 4 in the tube is placed in the reaction zone in the furnace tube 1 without putting in the sample; the heating device 2 is heated up, and the temperature measuring device 3 outside the tube is used to measure the real-time temperature as T 外 The real-time measurement value of the temperature measuring device 4 in the collection tube is T 内 , collect a series of T 内 With T 外 The corresponding value of The specific process of data collection is as follows: 外 =50℃, start measuring, record data every time the temperature rises by 50℃ until T 外 =1000℃, and 20 sets of corresponding values ​​are obtained; Fitting line generation stage: Divide the temperature range, perform segmented fitting based on the collected data, and use statistical analysis or machine learning algorithms to generate multiple segments describing T 内 With T 外 The fitted straight line between the relationship The specific process of generating the fitting line is as follows: take the heating time as the X-axis and the temperature as the Y-axis, and draw the T curve according to the collected data. 外 and T 内 Difference graphs, such as Figure 2 ; According to T 外 and T 内 The difference diagram is used to divide the temperature range. Specifically, the error is small below 350℃ (the coefficient is about 95%), the error is significantly increased from 350℃ to 700℃ (the coefficient is about 85%), and the error is further increased from 700℃ to 1000℃ (the coefficient is about 80%). Therefore, the entire temperature range is divided into three intervals for correction, namely T 外 ≤350℃ range, 350℃<T 外 ≤700℃ range, 700℃<T外 ≤1000℃ range; According to the three determined temperature intervals, the original data set is divided into three subsets, each of which contains the T 内 With T 外 The corresponding value of T is obtained by performing linear regression analysis on each subset, with the goal of finding the linear function, T 内 =m×T 外 +b, where m is the slope and b is the intercept; T 外 ≤350℃ range, T 内 =m1×T 外 +b1, m1=0.9101, b1=-12.729; 350℃<T 外 ≤700℃ range, T 内 =m2×T 外 +b2, m2=1.0326, b2=-55.886; 700℃<T 外 ≤1000℃ range, T 内 =m3×T 外 +b3, m3=1.3396, b3=-274.02.

[0031] The obtained fitted straight line is plotted on the scatter plot of the original data, such as Figure 3-5 , so that you can visually check the model fit.

[0032] Therefore, in actual use, the real-time temperature of the reaction zone in the tube furnace can be predicted according to the real-time temperature measured by the temperature measuring device 3 outside the tube through the fitting line.

[0033] Example 2: Tube furnace heating temperature calibration method The sample is placed in the reaction zone of the furnace tube. No temperature measuring device 4 is placed in the furnace tube. The target temperature is preset as T in the control system. 预设 ; Set the preset target temperature to T 预设 The temperature is transmitted to the control system, and the control system corrects the reaction zone in the tube furnace to reach the preset target temperature T according to the fitting line obtained in Example 1. 预设 The real-time measurement value of the temperature measuring device outside the tube, that is, the heating temperature T that the heating device needs to reach 加热装置 ; The heating device 2 heats up, and the temperature measuring device 3 outside the collection tube measures the temperature in real time as T 外 ; The control system will T 外 With T 加热温度 In comparison, if the real-time temperature T 外 Lower than T加热温度 , the control module drives the heating device to increase the temperature for heating; if the real-time temperature T 外 Equal to T 加热温度 , the control module drives the heating device to maintain the temperature.

[0034] Thereby, the temperature of the reaction zone in the tube furnace can be achieved to be the preset target heating temperature.

[0035] Example 3: Method for measuring reaction temperature in a visual tube furnace No temperature measuring device 4 is placed inside the furnace tube; Sprinkle the Mo source precursor evenly on the substrate silicon wafer, place the crucible carrying the substrate in the reaction zone of the furnace tube; place the crucible carrying sulfur powder upstream of the reaction zone of the furnace tube; The empirical temperature of 800°C required for the reaction in the reaction zone of the tube furnace is used as the preset target temperature. 预设 Transmit to control system; The control system calculates the fitting line obtained in Example 1 and corrects the reaction zone in the tube furnace to reach the preset target temperature T 预设 The real-time measurement value T of the temperature measuring device outside the tube 外 =801.7℃; The control system calculates the heating temperature T that the heating device needs to reach 加热装置阈值 =801.7℃+50℃=851.7℃, and T 加热装置阈值 =851.7℃ is fed back to the heating device; The heating device 2 heats up, and each node of the reaction is determined through the visualization window; Specifically, when a yellow halo appears on the edge of the sample and it slowly melts into a liquid ball, record the temperature T at this time. 外 It is 764℃.

[0036] The control system corrects the real-time temperature of the reaction area in the tube to T according to the fitting line obtained in Example 1. 内 =749.4℃; that is, the actual temperature T required for the melting reaction 熔融 It is 749.4℃.

[0037] Example 4: Tube furnace with temperature correction function A tube furnace with temperature correction function, such as Figure 1 , but does not include the temperature measuring device 4 inside the tube, including the furnace tube 1, the heating device 2, the temperature measuring device 3 outside the tube and the control system; the control system includes a correction module, which directly displays the real-time temperature of the reaction zone in the tube furnace by correcting the temperature.

[0038] The correction module needs to pre-store the fitting line and the preset calculation model obtained by the correction method of Example 1; Set the preset target temperature T in the preset temperature zone of the control system 预设 , set the preset target temperature T 预设 The control system calculates and corrects the reaction zone in the tube furnace to reach the preset target temperature T through the fitting line calculation. 预设 The real-time measurement value T of the temperature measuring device outside the tube 外 .

[0039] The control system calculates the heating temperature T that the heating device needs to reach according to the preset calculation model. 加热装置阈值 and feed it back to the heating device.

[0040] The control device includes a feedback adjustment module, and the control system obtains the real-time measurement value T of the external temperature measuring device 外 The heating temperature T required by the heating device 加热装置阈值 Compare and control the real-time measurement value T of the temperature measuring device outside the tube 外 The heating temperature T that the heating device needs to reach 加热装置阈值 .

Claims

1. A method for calibrating the internal and external temperatures of a tubular furnace, characterized in that: The steps include: Data collection stage: No reactants are placed in the tube furnace. After heating, a series of real-time measurement values ​​T of the temperature measuring device in the tube are collected. 内 The real-time measurement value T of the temperature measuring device outside the tube 外 The corresponding value of Fitting line generation stage: Divide the temperature range, perform segmented fitting based on the collected data, and use statistical analysis or machine learning algorithms to generate multiple segments describing T 内 With T 外 The fitted line function relationship between them; Data correction stage: During use, the real-time temperature of the reaction zone in the tubular furnace is obtained through the measurement value and fitting line of the temperature measuring device outside the tube.

2. The method for calibrating the internal and external temperatures of a tube furnace according to claim 1, characterized in that: The fitting line generation stage includes the following steps: draw T according to the collected data 外 and T 内 Difference diagram and temperature small interval division to obtain multiple fitting lines.

3. The method for calibrating the internal and external temperatures of a tube furnace according to claim 1, characterized in that: The data correction stage includes: the real-time measurement value T of the temperature measuring device outside the tube 外 The temperature is transmitted to the control system, which calculates and corrects the real-time temperature T of the reaction zone in the tube furnace through fitting line calculation. 内 .

4. A method for accurately obtaining the reaction temperature in a tubular furnace, characterized in that: The method comprises adopting any one of the correction methods of claims 1 to 3 to obtain the reaction temperature in the tubular furnace.

5. A method for accurately controlling the heating temperature of a tubular furnace, characterized in that: Set the preset target temperature T in the control system of the tube furnace 预设 , the correction method described in any one of claims 1 to 3 is used to obtain the heating temperature T required to be reached by the heating device 加热装置 ; The control system obtains the real-time measurement value T of the temperature measuring device outside the tube 外 The heating temperature T required by the heating device 加热装置 Compare and control the real-time measurement value T of the temperature measuring device outside the tube 外 The heating temperature T that the heating device needs to reach 加热装置 .

6. A method for accurately obtaining the reaction temperature in a visualized tube furnace, characterized in that: The steps include: Obtaining a fitting line according to the correction method according to any one of claims 1 to 3; The empirical temperature required for the reaction in the reaction zone of the tube furnace is taken as the preset target temperature T 预设 , set the preset target temperature T 预设 The control system calculates and corrects the reaction zone in the tube furnace to reach the preset target temperature T through the fitting line calculation. 预设 The real-time measurement value T of the temperature measuring device outside the tube 外 ; The control system calculates the heating temperature T that the heating device needs to reach according to the preset calculation model 加热装置阈值 , and feed it back to the heating device. The preset calculation model here is to ensure that the reaction temperature in the reaction zone of the tube furnace is not less than the actual required reaction temperature; Control the heating device and determine each node of the reaction through the visualization window; The control system uses the fitting line to convert the real-time measurement value T 外 Corrected to the real-time temperature T of the reaction zone in the tube furnace 内 , that is, the actual reaction temperature.

7. The method for accurately obtaining the reaction temperature in a visualized tube furnace according to claim 6, characterized in that: Each reaction node in step (3) includes one or more of the following: melting of powder raw materials, film formation, film etching, and film shape change.

8. The method for accurately obtaining the reaction temperature in a visualized tube furnace according to claim 6, characterized in that: The calculation model preset in step (2) is T 加热装置阈值 =T 外 +50℃.

9. A tubular furnace with temperature correction function, characterized in that: It comprises a furnace tube, a heating device, a control system, and a temperature measuring device outside the tube; the control system comprises a correction module, which directly displays the real-time temperature of the reaction zone in the tube furnace by correcting the temperature; the correction module stores the fitting line obtained by using any correction method of claims 1-3.

10. The tubular furnace with temperature correction function according to claim 9, characterized in that: Set the preset target temperature T in the preset temperature zone of the control system 预设 , set the preset target temperature T 预设 The control system calculates and corrects the reaction zone in the tube furnace to reach the preset target temperature T through the fitting line calculation. 预设 The real-time measurement value T of the temperature measuring device outside the tube 外 , control the heating temperature T that the heating device needs to reach 加热装置 Equal to the real-time measurement value T of the temperature measuring device outside the tube 外 .

11. The tube furnace with temperature correction function according to claim 10, characterized in that: If the preset target temperature T 预设 is the empirical temperature. The correction module also stores a preset calculation model. The control system calculates the heating temperature T that the heating device needs to reach according to the preset calculation model. 加热装置阈值 .

12. The tubular furnace with temperature correction function according to claim 11, characterized in that: The preset calculation model is T 加热装置阈值 =T 外 +50℃.

13. The tubular furnace with temperature correction function according to claim 12, characterized in that: The control system also includes a feedback adjustment module, which obtains the real-time measurement value T of the external temperature measuring device. 外 The heating temperature T required by the heating device 加热装置 or T 加热装置阈值 Compare and control the real-time measurement value T of the temperature measuring device outside the tube 外 The heating temperature T that the heating device needs to reach 加热装置 or T 加热装置阈值 .

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