Thermocouple hot corrosion detection device and detection method and semiconductor manufacturing equipment

Abstract

The invention provides a thermocouple thermal corrosion detection device, a detection method and semiconductor manufacturing equipment, which can detect the thermal corrosion condition of a thermocouple when the thermocouple is in a constant-temperature environment, and has high detection accuracy. The detection device comprises a detection circuit and a control circuit, a first connecting end of the detection circuit is connected with a first cold end of the thermocouple, a second connecting end of the detection circuit is connected with a second cold end of the thermocouple, and the control circuit is used for responding to received state indication information, obtaining a voltage signal or a current signal in the detection circuit and outputting the voltage signal or the current signal. The state indication information represents that the thermocouple is in a constant-temperature environment. The thermoelectric force generated by the thermocouple in the constant-temperature environment is relatively stable, so that the thermal corrosion detection of the thermocouple is more accurate. According to the thermocouple hot corrosion detection device, no extra power supply is added, and the influence of the extra power supply on the stability of thermoelectric force generated by the thermocouple can be avoided.

Description

Technical Field

[0001] The present application relates to the technical field of semiconductor manufacturing, and discloses a thermocouple thermal corrosion detection device, a detection method and semiconductor manufacturing equipment. Background Art

[0002] In the semiconductor manufacturing process, thermocouples are usually used to measure the temperature inside the furnace in the furnace tube equipment. The temperature control device can adjust the temperature inside the furnace through the temperature measured by the thermocouple.

[0003] However, in a high temperature environment, as the use time increases, the thermocouple may be thermally corroded. If the thermocouple is disconnected due to thermal corrosion, it will cause the thermocouple to fail. The temperature control device cannot effectively adjust the temperature in the furnace, and the products being processed in the furnace are discarded. How to detect the thermal corrosion of thermocouples in time is in urgent need of a solution. Summary of the invention

[0004] The present application provides a thermocouple thermal corrosion detection device and semiconductor manufacturing equipment, which can detect the thermal corrosion of the thermocouple when the thermocouple is in a constant temperature environment and has a high detection accuracy.

[0005] In a first aspect, an embodiment of the present application provides a thermocouple thermal corrosion detection device, which may include a detection circuit and a control circuit. The detection circuit may include a first connection end and a second connection end; the first connection end is used to connect the first cold end of the thermocouple, and the second connection end is used to connect the second cold end of the thermocouple. The control circuit is used to respond to the received status indication information and obtain the voltage signal or current signal in the detection circuit, and the status indication information indicates that the thermocouple is in a constant temperature environment.

[0006] In the embodiment of the present application, when the thermocouple is in a constant temperature environment, the thermoelectric potential generated by the thermocouple is relatively stable, making the detection of thermal corrosion of the thermocouple more accurate. In addition, no additional power supply is added, which can avoid the influence of the additional power supply on the temperature of the thermocouple, thereby avoiding the influence on the thermoelectric potential generated by the thermocouple, making the detection of thermal corrosion of the thermocouple more accurate.

[0007] Optionally, after entering the idea state, the semiconductor manufacturing equipment can send status indication information to the control circuit in the thermocouple thermal corrosion detection device provided by the present application, and the status indication information can indicate that the thermocouple is in a constant temperature environment. The control circuit can control the detection circuit to connect with the thermocouple, and obtain the voltage signal or current signal in the detection circuit to detect whether the thermocouple has thermal corrosion. In this way, the constant temperature stage of the semiconductor manufacturing equipment can be used to detect whether the thermocouple has thermal corrosion, without the need to disassemble the thermocouple.

[0008] In a possible implementation, the embodiment of the present application provides a thermocouple thermal corrosion detection device, wherein the detection circuit may include a first voltage divider unit, a second voltage divider unit and a first switch; wherein the first connection end, the first voltage divider unit, the first switch, the second voltage divider unit and the second connection end are connected in series in sequence.

[0009] In the embodiment of the present application, the control circuit can use the voltage signal or current signal of the detection circuit to calculate the resistance of the thermocouple in the constant temperature environment, and can combine the resistance of the thermocouple without thermal corrosion to determine whether the thermocouple is currently thermally corroded. This method has a lower cost.

[0010] In a possible implementation, an embodiment of the present application provides a thermocouple thermal corrosion detection device, wherein the control circuit includes a first pressure measuring circuit and a second pressure measuring circuit; the first pressure measuring circuit is used to detect the voltage of the first voltage dividing unit; and the second pressure measuring circuit is used to detect the voltage of the second voltage dividing unit.

[0011] In the embodiment of the present application, the control circuit can use the voltage signal of the detection circuit to calculate the resistance of the thermocouple in the constant temperature environment, and can combine the resistance of the thermocouple without thermal corrosion to determine whether the thermocouple is currently thermally corroded. This method has a lower cost.

[0012] In a possible implementation, the embodiment of the present application provides a thermocouple thermal corrosion detection device, wherein the detection circuit also includes a third connection terminal and a first branch, the third connection terminal is used to connect to the ground terminal, and the detection circuit also includes a first branch, one end of the first branch is connected to the first end of the first voltage divider unit, and the other end of the first branch is connected to the third connection terminal; the first end of the first voltage divider unit is an end of the first voltage divider unit connected to the first switch; the first branch includes a second switch and a third voltage divider unit connected in series.

[0013] In an embodiment of the present application, the first voltage divider unit, the second voltage divider unit, the third voltage divider unit, the first switch, and the second switch in the detection circuit can support the use of different circuits to perform multiple measurements of the resistance of the thermocouple, which can improve the measurement accuracy and reduce the impact of interference signals in the measurement on the detection results.

[0014] In a possible implementation, an embodiment of the present application provides a thermocouple thermal corrosion detection device, wherein the detection circuit also includes a second branch; one end of the second branch is connected to the first end of the second voltage divider unit, and the other end of the second branch is connected to the third connection end; the first end of the second voltage divider unit is an end of the second voltage divider unit connected to the first switch; the second branch includes a third switch and a fourth voltage divider unit connected in series.

[0015] In an embodiment of the present application, the first voltage divider unit, the second voltage divider unit, the third voltage divider unit, the fourth voltage divider unit, the first switch, and the second switch in the detection circuit can support the use of different circuits to perform multiple measurements of the resistance of the thermocouple, which can improve the measurement accuracy and reduce the impact of interference signals in the measurement on the detection results.

[0016] In a possible implementation, an embodiment of the present application provides a thermocouple thermal corrosion detection device, wherein the current signal of the detection circuit includes the current generated by the thermocouple, and the current is used to determine whether thermal corrosion occurs to the thermocouple.

[0017] In the embodiment of the present application, the control circuit can determine whether thermal corrosion occurs to the thermocouple by measuring the current in the detection circuit loop.

[0018] In a second aspect, an embodiment of the present application further provides a semiconductor manufacturing device, which may include a thermocouple and a thermocouple thermal corrosion detection device as provided in the first aspect and any possible implementation manner thereof.

[0019] In a third aspect, the present application also provides a method for detecting thermal corrosion of a thermocouple, which can be applied to a thermocouple thermal corrosion detection device in the first aspect and any possible embodiment thereof. The method can include the following steps:

[0020] The reference internal resistance of the thermocouple is measured in a constant temperature environment without thermal corrosion;

[0021] The detection circuit is used to collect voltage signals or current signals in a constant temperature environment; the control circuit calculates the measured resistance of the thermocouple based on the voltage signal or the current signal, compares the measured resistance with the reference internal resistance, and determines the thermal corrosion state of the thermocouple.

[0022] In one possible implementation, the control circuit controls the detection circuit to obtain at least one voltage signal at at least one moment, and calculates at least one measured resistance based on the obtained voltage signal, wherein the at least one measured resistance includes one or more of a first measured resistance value, a second measured resistance value, and a third measured resistance value; the at least one measured resistance and the reference internal resistance are compared with each other to determine whether the thermocouple is corroded.

[0023] In one possible implementation, the detection circuit includes a first voltage divider unit, a second voltage divider unit, and a first switch; at a first moment, the control circuit is used to control the first switch to be in an on state, and obtain a first voltage of the first voltage divider unit and a second voltage of the second voltage divider unit; and a first measured resistance value of the thermocouple is calculated based on the first voltage and the second voltage.

[0024] In a possible implementation manner, the detection circuit further includes a first branch, the first branch includes a second switch and a third voltage dividing unit connected in series, and the first voltage dividing unit is grounded through the first branch;

[0025] At a second moment after the first moment, the control circuit is used to control the first switch to be in an open state and the second switch to be in an on state; a third voltage of the first voltage divider unit is obtained, and a second measured resistance value of the thermocouple is calculated based on the third voltage.

[0026] In a possible implementation manner, the detection circuit further includes a second branch, the second branch includes a third switch and a fourth voltage dividing unit connected in series, and the second voltage dividing unit is grounded through the first branch;

[0027] At a third moment after the second moment, the control circuit is used to control the first switch to be in an open state, the second switch to be in an open state, and the third switch to be in an on state; a fourth voltage of the second voltage divider unit is obtained, and a third measured resistance value of the thermocouple is calculated based on the fourth voltage.

[0028] In addition, the technical effects brought about by the second aspect and any possible implementation manner thereof, and the technical effects brought about by the third aspect and any possible implementation manner thereof, can be referred to the technical effects brought about by different implementation manners in the first aspect, and will not be repeated here.

[0029] Other features and advantages of the present application will be described in the following description, and partly become apparent from the description, or be understood by practicing the present application. The purpose and other advantages of the present application can be realized and obtained by the structures specifically pointed out in the written description, claims, and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0031] Figure 1 A schematic diagram showing an application scenario;

[0032] Figure 2 A schematic diagram of the structure of a thermocouple is shown;

[0033] Figure 3 A schematic diagram of the structure of a thermocouple thermal corrosion detection device provided in an embodiment of the present application;

[0034] Figure 4 A schematic diagram of the structure of a detection circuit in a thermocouple thermal corrosion detection device provided in an embodiment of the present application;

[0035] Figure 5a A schematic diagram of the structure of a thermocouple thermal corrosion detection device provided in an embodiment of the present application;

[0036] Figure 5b A schematic diagram of the structure of a thermocouple thermal corrosion detection device provided in an embodiment of the present application;

[0037] Figure 6 A schematic diagram of the structure of a detection circuit in a thermocouple thermal corrosion detection device provided in an embodiment of the present application;

[0038] Figure 7a A schematic diagram of the structure of a thermocouple thermal corrosion detection device provided in an embodiment of the present application;

[0039] Figure 7b A schematic diagram of the structure of a thermocouple thermal corrosion detection device provided in an embodiment of the present application;

[0040] Figure 8 A schematic diagram of the structure of a detection circuit in a thermocouple thermal corrosion detection device provided in an embodiment of the present application;

[0041] Figure 9a A schematic diagram of the structure of a thermocouple thermal corrosion detection device provided in an embodiment of the present application;

[0042] Figure 9b A schematic diagram of the structure of a thermocouple thermal corrosion detection device provided in an embodiment of the present application;

[0043] Fig.10 A schematic flow chart of a thermocouple thermal corrosion detection method provided in an embodiment of the present application. DETAILED DESCRIPTION

[0044] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below in conjunction with the accompanying drawings.

[0045] First, the application scenarios of the embodiments of the present application are introduced. Figure 1In the semiconductor manufacturing process, the furnace tube equipment can provide a high temperature environment. The temperature inside the furnace tube equipment is generally adjusted by a temperature control device. The temperature of the furnace tube equipment is generally measured by a thermocouple. In a high temperature environment, the thermocouple may be thermally corroded as the service time increases. If the thermocouple is disconnected due to thermal corrosion, the temperature control device cannot effectively adjust the temperature, causing the furnace tube equipment to be unable to process qualified products. If there are products being processed in the furnace tube equipment, the processed products will also be discarded due to unqualified.

[0046] At present, in the related technology of detecting whether the thermocouple is disconnected, one method is to use a multimeter to measure whether the thermocouple is disconnected when the furnace tube equipment is not working. This method can only determine whether the resistance is disconnected under a limited number of times, but cannot determine whether there is a risk of disconnection due to thermal corrosion of the thermocouple. Another method is to use an external power supply to detect the resistance change of the thermocouple, because the external power supply has an impact on the temperature measurement function of the thermocouple. Although this method can measure the resistance change of the thermocouple, it will affect the temperature measurement function of the thermocouple itself.

[0047] In view of this, an embodiment of the present application provides a thermocouple thermal corrosion detection device, which can timely detect whether thermal corrosion occurs in the thermocouple without affecting the temperature measurement function of the thermocouple.

[0048] It should be noted that the multiple involved in the embodiments of the present application refers to two or more. In addition, it should be understood that in the description of the embodiments of the present application, the words "first", "second", etc. are only used for the purpose of distinguishing the description, and cannot be understood as indicating or implying relative importance, nor can they be understood as indicating or implying an order.

[0049] Please combine Figure 2 , usually a thermocouple includes two metals of different materials. The thermocouple involved in the embodiments of the present application can be any existing thermocouple, as well as a thermocouple that may appear in the future and has the same temperature measurement principle as the existing thermocouple.

[0050] For ease of introduction, the common end point of two metals of different materials in the thermocouple is called the measuring end. The unconnected end of each metal material is called the cold end. It can be seen that the thermocouple has two cold ends, which are respectively recorded as cold end CE1 and cold end CE2 in the embodiment of the present application. Usually, the cold end CE1 and the cold end CE2 are usually connected to a digital-to-analog conversion module, which can convert the thermoelectric potential generated by the thermocouple into a corresponding temperature, thereby measuring the temperature of the environment in which the measuring end of the thermocouple is located.

[0051] Figure 3 An exemplary thermocouple thermal corrosion detection device is shown, which may include a detection circuit and a control circuit, wherein the detection circuit may have a first connection terminal D1 and a second connection terminal D2.

[0052] The first connection end D1 and the second connection end D2 are used to connect to the two cold ends CE1 and CE2 of the thermocouple, respectively. For example, the first connection end D1 is used to connect to the cold end CE1 of the thermocouple. The second connection end D2 is used to connect to the cold end CE2 of the thermocouple. For another example, the first connection end D1 is used to connect to the cold end CE2 of the thermocouple, and the second connection end D2 is used to connect to the cold end CE1 of the thermocouple. The present application does not impose too many restrictions on this, and for ease of introduction, the cold end connected to the first connection end D1 is recorded as the first cold end, and the cold end connected to the second connection end D2 is recorded as the second cold end.

[0053] In the embodiment of the present application, the control circuit can exchange data or information with other electronic devices.

[0054] In one possible application scenario, the control circuit can receive status indication information provided by semiconductor manufacturing equipment. Usually, there are multiple temperature adjustment stages during the operation of semiconductor manufacturing equipment, such as the heating stage, the constant temperature stage, and the cooling stage. The semiconductor manufacturing equipment operates in the constant temperature stage, which is generally also the stage after the equipment is run. The stage after the semiconductor manufacturing equipment is run can be called entering the idea state. In this state, the semiconductor manufacturing equipment is generally in a constant temperature state, the temperature remains stable, and there is no product in the semiconductor manufacturing equipment.

[0055] After entering the idea state, the semiconductor manufacturing equipment can send status indication information to the control circuit in the thermocouple thermal corrosion detection device provided by the present application, and the status indication information can indicate that the thermocouple is in a constant temperature environment. The control circuit can control the detection circuit to connect with the thermocouple and obtain the voltage signal or current signal in the detection circuit to detect whether the thermocouple has thermal corrosion. In this way, the constant temperature stage of the semiconductor manufacturing equipment can be used to detect whether the thermocouple has thermal corrosion, without the need to disassemble the thermocouple.

[0056] In another possible application scenario, the control circuit can receive status indication information provided by the heating device. The thermocouple can be placed in the heating device, and the heating device can change the temperature of the environment in which the thermocouple is located to provide a constant temperature environment for the thermocouple. Optionally, the temperature of the constant temperature environment can be 600°C. After the heating device provides a constant temperature environment and continues for a preset period of time, it can send status indication information to the control circuit. The status indication information can indicate that the thermocouple is in a constant temperature environment. The control circuit can respond to the received status indication information, control the detection circuit to connect the thermocouple to the ground terminal, and judge the thermal corrosion of the thermocouple by obtaining the voltage signal or current signal in the detection circuit.

[0057] In the embodiment of the present application, when the thermocouple is in a constant temperature environment, the thermoelectric potential generated by the thermocouple is relatively stable, making the detection of thermal corrosion of the thermocouple more accurate. In addition, no additional power supply is added, which can avoid the influence of the additional power supply on the temperature of the thermocouple, thereby avoiding the influence on the thermoelectric potential generated by the thermocouple, making the detection of thermal corrosion of the thermocouple more accurate.

[0058] In the thermocouple thermal corrosion detection device provided in the embodiment of the present application, the detection circuit may include a voltage divider unit. Each voltage divider unit may include at least one voltage divider resistor. Optionally, the control circuit may include a voltage measuring circuit, and the control circuit may obtain the voltage of the voltage divider unit through the voltage measuring circuit. The control circuit may pre-store the thermoelectric potential generated when the thermocouple works normally in the constant temperature environment. The control circuit may pre-store the internal resistance of the thermocouple in the constant temperature environment when no thermal corrosion occurs, which is recorded as the reference internal resistance. The control circuit may calculate the internal resistance of the thermocouple based on the pre-stored thermoelectric potential, the resistance value of the voltage divider resistor, and the voltage of the voltage divider resistor obtained. The control circuit may compare the calculated internal resistance with the stored reference internal resistance to determine whether the thermocouple has undergone thermal corrosion. Generally, the internal resistance of the thermocouple after thermal corrosion occurs is different from the internal resistance of the thermocouple before thermal corrosion occurs.

[0059] Optionally, the control circuit may include a measuring current, and the measuring current may be obtained by the current generated by the thermocouple in a constant temperature environment. The control circuit may pre-store the current generated when the thermocouple is in the constant temperature environment and no thermal corrosion occurs to the thermocouple, and record it as a reference current. The control circuit may compare the measured current with the stored reference current to determine whether thermal corrosion occurs to the thermocouple.

[0060] Figure 4 According to an exemplary embodiment, a schematic diagram of the structure of a detection circuit in a thermocouple thermal corrosion detection device is shown. The detection circuit may include a first voltage divider unit R1, a first switch S1, and a second voltage divider unit R2 connected in series in sequence. Among them, the first connection terminal D1, the first voltage divider unit R1, the first switch S1, the second voltage divider unit R2, and the second connection terminal D2 are connected in series in sequence. Generally speaking, the resistance value of the first voltage divider unit R1 and the resistance value of the second voltage divider unit R2 cannot be much greater than the internal resistance of the thermocouple in a constant temperature environment. For example, the resistance value of the first voltage divider unit R1 and the resistance value of the second voltage divider unit R2 are preferably similar to the internal resistance value of the thermocouple in a constant temperature environment, or less than the internal resistance value of the thermocouple in a constant temperature environment, to prevent the process of measuring the resistance of the thermocouple from affecting the temperature measurement of the semiconductor manufacturing equipment. The first voltage divider unit R1 may include at least one resistor. The second voltage divider unit R2 may include at least one resistor.

[0061] Combination Figure 4 A possible implementation of the detection circuit provided is to combine Figure 5a The control circuit may include a controller, a first pressure measuring circuit T1 and a second pressure measuring circuit T2. The controller may control the state of each switch in the detection circuit and obtain the data detected by each pressure measuring circuit.

[0062] The first voltage measuring circuit T1 can be connected to the first voltage dividing unit R1. The first voltage measuring circuit T1 can be used to detect the voltage across the first voltage dividing unit. The second voltage measuring circuit T2 can be connected to the second voltage dividing unit R2. The second voltage measuring circuit T2 can be used to detect the voltage across the second voltage dividing unit.

[0063] In the case where the thermocouple has not been thermally corroded, such as when the thermocouple leaves the factory, the thermocouple thermal corrosion detection device can measure the thermocouple. In the case where the thermocouple has not been thermally corroded, the thermocouple in a constant temperature environment is detected. The control circuit can calculate the internal resistance of the thermocouple in the case where thermal corrosion has not occurred based on the voltage of the first voltage divider unit R1, the voltage of the second voltage divider unit R2, the first voltage divider unit R1, the second voltage divider unit R2, and the thermoelectric potential generated by the thermocouple, and record it as the reference internal resistance. The reference internal resistance can be used to subsequently determine whether thermal corrosion has occurred in the thermocouple.

[0064] The thermocouple thermal corrosion detection device can exchange data or information with other devices so that the control circuit can receive the aforementioned status indication information, and the status indication information can indicate that the thermocouple is in a constant temperature environment. The control circuit can respond to the status indication information, and the control circuit uses the detection circuit to collect a voltage signal or a current signal. The control circuit can calculate the measured resistance of the thermocouple based on the voltage signal or the current signal, compare the measured resistance with the reference internal resistance, and determine the thermal corrosion state of the thermocouple.

[0065] In some examples, the control circuit can respond to the status indication information, control the detection circuit to obtain the voltage of the first voltage divider unit R1 and the voltage of the second voltage divider unit R2 at the first moment, and calculate the first measured resistance value based on the voltage of the first voltage divider unit R1 and the voltage of the second voltage divider unit R2. The control circuit can compare the first measured resistance value with the pre-stored reference resistance value to determine whether the thermocouple has (or has) thermal corrosion. For example, the control circuit can respond to receiving the status indication information and control the first switch S1 to be in the on state at the first moment. The control circuit can obtain the voltage of the first voltage divider unit R1 and the voltage of the second voltage divider unit R2 through the first voltage measuring circuit T1 and the second voltage measuring circuit T2, respectively. At this time, the voltage of the first voltage divider unit R1 obtained is recorded as the first voltage, and the voltage of the second voltage divider unit R2 obtained is recorded as the second voltage. The control circuit can calculate the resistance value of the thermocouple based on the first voltage and the second voltage. The control circuit can compare the calculated measured resistance value of the thermocouple with the pre-stored reference resistance value. If the two are inconsistent, it can be determined that the thermocouple has (or has) thermal corrosion.

[0066] Another possible implementation method is to combine Figure 5b The control circuit may include a current measuring circuit. The current measuring circuit is connected to the detection circuit and can detect the current generated by the thermocouple.

[0067] When the thermocouple does not suffer from thermal corrosion, such as when the thermocouple leaves the factory, the thermocouple thermal corrosion detection device can measure the thermocouple. When the thermocouple does not suffer from thermal corrosion, the thermocouple in a constant temperature environment is detected. The control circuit can record the current obtained in this situation as a reference current, and the reference current can be used to subsequently determine whether the thermocouple suffers from thermal corrosion.

[0068] The thermocouple thermal corrosion detection device can exchange data or information with other devices. The control circuit can respond to receiving the status indication information and control the first switch S1 to be in the on state at the first moment. The control circuit can obtain the current generated by the thermocouple. The control circuit can compare the obtained current with the pre-stored reference current. If the two are inconsistent, it can be determined that the thermocouple has (or has) thermal corrosion.

[0069] Figure 6 According to an exemplary embodiment, a schematic diagram of the structure of a detection circuit in a thermocouple thermal corrosion detection device is shown. The detection circuit may include the aforementioned first connection terminal D1, the second connection terminal D2, the first voltage dividing unit R1, the first switch S1 and the second voltage dividing unit R2. The specific connection relationship can be referred to the aforementioned introduction and will not be repeated here.

[0070] The detection circuit may further include a third connection terminal D3 and a first branch, wherein the third connection terminal D3 is used to be connected to the ground terminal. The first end of the first branch may be connected to the first end of the first voltage divider unit R1, and the second end of the first branch may be connected to the third connection terminal D3. The first end of the first voltage divider unit R1 is an end of the first voltage divider unit R1 connected to the first switch S1. The first branch may include a second switch S2 and a third voltage divider unit R3 connected in series. The third voltage divider unit R3 may include at least one resistor.

[0071] Combination Figure 6 A possible implementation of the detection circuit provided is to combine Figure 7a , the control circuit may include a first voltage measuring circuit T1 and a second voltage measuring circuit T2. The first voltage measuring circuit T1 may be connected to the first voltage dividing unit R1. The first voltage measuring circuit T1 may be used to detect the voltage across the first voltage dividing unit. The second voltage measuring circuit T2 may be connected to the second voltage dividing unit R2. The second voltage measuring circuit T2 may be used to detect the voltage across the second voltage dividing unit.

[0072] When the thermocouple does not suffer from thermal corrosion, such as when the thermocouple leaves the factory, the thermocouple thermal corrosion detection device can measure the thermocouple. When the thermocouple does not suffer from thermal corrosion, the thermocouple in a constant temperature environment is detected. For example, the thermoelectric potential generated by the thermocouple is detected. The control circuit can calculate the internal resistance of the thermocouple when thermal corrosion does not occur based on the voltage of the first voltage divider unit R1, the voltage of the second voltage divider unit R2, and the thermoelectric potential generated by the thermocouple obtained in this situation, and record it as the reference internal resistance. The reference internal resistance can be used to subsequently determine whether thermal corrosion occurs in the thermocouple.

[0073] In some examples, the thermocouple thermal corrosion detection device can exchange data or information with other devices so that the control circuit can receive the aforementioned status indication information, and the status indication information can indicate that the thermocouple is in a constant temperature environment. The control circuit can perform multiple measurements in response to the received status indication information. In each measurement, the control circuit can use the detection circuit to collect voltage signals. The control circuit can calculate the measured resistance value of the thermocouple based on the collected voltage signal. Thus, the control circuit can calculate multiple measured resistance values. In an embodiment of the present application, the measured resistance of the thermocouple includes the multiple measured resistance values. The control circuit can compare the measured resistance values ​​and the reference internal resistance with each other to determine the thermal corrosion state of the thermocouple.

[0074] Exemplarily, the control circuit can respond to receiving the status indication information and perform the first measurement control at the first time t1. The control circuit can control the first switch S1 to be in the on state, and control the second switch S2 to be in the off state. Then the control circuit can obtain the voltage V1_t1 of the first voltage divider unit R1 through the first voltage measuring circuit T1, which is also the voltage of the first voltage divider unit R1 corresponding to the first measurement control; the control circuit can obtain the voltage V2_t1 of the second voltage divider unit R2 through the second voltage measuring circuit T2, which is also the voltage of the second voltage divider unit R2 corresponding to the first measurement control.

[0075] The control circuit can calculate the measured resistance value of the thermocouple based on the voltage V1_t1 of the first voltage divider unit R1, the voltage V2_t1 of the second voltage divider unit R2, the first voltage divider unit R1 and the second voltage divider unit R2 corresponding to the first measurement control, and record it as the first measured resistance value. The first measured resistance value represents the internal resistance of the thermocouple calculated by the control circuit using the parameters obtained in the first measurement control. The control circuit can compare the calculated first measured resistance value with a pre-stored reference resistance value.

[0076] To improve the measurement accuracy, the control circuit performs the second measurement control at the second moment t2. The second moment t2 is after the first moment t1, and the duration between the second moment t2 and the first moment t1 is a preset duration. The control circuit can control the first switch S1 to be in an open circuit state, and control the second switch S2 to be in an on state. Then the control circuit can obtain the voltage V1_t2 of the first voltage divider unit R1 through the first voltage measuring circuit T1, which is also the voltage of the first voltage divider unit R1 corresponding to the second measurement control. The control circuit can calculate the measured resistance value of the thermocouple based on the voltage V1_t2 of the first voltage divider unit R1, the first voltage divider unit R1, the third voltage divider unit R3 and the stored thermoelectric potential generated by the thermocouple, and record it as the second measured resistance value. Among them, the second measured resistance value represents the internal resistance of the thermocouple calculated by the control circuit using the parameters obtained in the second measurement control. The control circuit can compare the calculated second measured resistance value with the pre-stored reference resistance value.

[0077] The control circuit can compare the first measured resistance value and the second measured resistance value respectively calculated in the two measurements with the pre-stored reference resistance value to determine whether thermal corrosion occurs to the thermocouple.

[0078] In some examples, if the first measured resistance value is equal to the second measured resistance value and is inconsistent with the reference resistance value, the control circuit can determine that thermal corrosion has occurred in the thermocouple. If the first measured resistance value is equal to the second measured resistance value and is consistent with the reference resistance value, the control circuit can determine that thermal corrosion has not occurred in the thermocouple. If the first measured resistance value is not equal to the second measured resistance value, it can reflect that there is an interference signal that affects the measurement. The control circuit can re-execute the operations in the first measurement control and the second measurement control.

[0079] In other examples, if the first measured resistance value is inconsistent with the reference resistance value, and the second measured resistance value is inconsistent with the reference resistance value, it can be determined that thermal corrosion has occurred in the thermocouple. If the first measured resistance value is consistent with the reference resistance value, and the second measured resistance value is inconsistent with the reference resistance value, the control circuit can re-execute the operations in the first measurement control and the second measurement control. If the second measured resistance value is consistent with the reference resistance value, and the first measured resistance value is inconsistent with the reference resistance value, the control circuit can re-execute the operations in the first measurement control and the second measurement control. If the first measured resistance value is consistent with the reference resistance value, and the second measured resistance value is consistent with the reference resistance value, it can be determined that thermal corrosion has not occurred in the thermocouple.

[0080] In the embodiment of the present application, the internal resistance of the thermocouple is measured multiple times to avoid the influence of interference signals in the measurement on the judgment result, so that the thermocouple thermal corrosion detection device provided in the embodiment of the present application has a higher detection accuracy.

[0081] In some possible application scenarios, the control circuit can perform any one of the two measurement controls mentioned above. The control circuit can compare the measured resistance value of the thermocouple calculated in the one measurement operation with the reference internal resistance to determine whether thermal corrosion occurs in the thermocouple.

[0082] Combination Figure 6 A possible implementation of the detection circuit provided is to combine Figure 7b The control circuit may include a current measuring circuit. The current measuring circuit is connected to the first connection terminal D1 of the detection circuit. Alternatively, the current measuring circuit is connected to the second connection terminal D2. The current measuring circuit can detect the current generated by the thermocouple.

[0083] When the thermocouple does not suffer from thermal corrosion, such as when the thermocouple leaves the factory, the thermocouple thermal corrosion detection device can measure the thermocouple. When the thermocouple does not suffer from thermal corrosion, the thermocouple in a constant temperature environment is detected. The control circuit can record the current obtained in this situation as a reference current, and the control circuit can calculate the resistance of the thermocouple based on the reference current, which is recorded as a reference resistance. The reference resistance can be used to subsequently determine whether the thermocouple suffers from thermal corrosion.

[0084] The thermocouple thermal corrosion detection device can exchange data or information with other devices. The control circuit can respond to receiving the status indication information and perform the first measurement control at the first time t1. The control circuit can control the first switch S1 to be in the on state and control the second switch S2 to be in the off state. The control circuit can obtain the current generated by the thermocouple in the first measurement control through the current measuring circuit. The control circuit can calculate the measured resistance value of the thermocouple based on the current obtained in the first measurement control, the first voltage divider unit R1, the second voltage divider unit R2, and the stored thermoelectric potential of the thermocouple, and record it as the first measured resistance value.

[0085] Then, the control circuit performs the second measurement control at the second moment t2. The control circuit can control the first switch S1 to be in an open circuit state, and control the second switch S2 to be in an on state. The control circuit can obtain the current generated by the thermocouple in the second measurement control through the current measuring circuit. The control circuit can calculate the measured resistance value of the thermocouple based on the current obtained in the second measurement control, the first voltage divider unit R1, the third voltage divider unit R3, and the stored thermoelectric potential of the thermocouple, and record it as the second measured resistance value.

[0086] Similarly, the control circuit can compare the first measured resistance value and the second measured resistance value respectively calculated in the two measurement controls with the pre-stored reference resistance value. For details, please refer to the relevant introduction in the above embodiment, which will not be repeated here.

[0087] Figure 8 According to an exemplary embodiment, a schematic diagram of the structure of a detection circuit in a thermocouple thermal corrosion detection device is shown. The detection circuit may include the aforementioned first connection terminal D1, the second connection terminal D2, the first voltage dividing unit R1, the first switch S1, the second voltage dividing unit R2, the third connection terminal D3 and the first branch. The specific connection relationship can be referred to the aforementioned introduction, which will not be repeated here.

[0088] The detection circuit may further include a second branch. The first end of the second branch may be connected to the first end of the second voltage divider R2, and the second end of the second branch may be connected to the third connection end D3. The first end of the second voltage divider R2 is an end of the second voltage divider R2 connected to the first switch S1.

[0089] The second branch may include a third switch S3 and a fourth voltage dividing unit R4 connected in series. The fourth voltage dividing unit R4 may include at least one resistor.

[0090] Combination Figure 8 A possible implementation of the detection circuit provided is to combine Figure 9a, the control circuit may include a first voltage measuring circuit T1 and a second voltage measuring circuit T2. The first voltage measuring circuit T1 may be connected to the first voltage dividing unit R1. The first voltage measuring circuit T1 may be used to detect the voltage across the first voltage dividing unit. The second voltage measuring circuit T2 may be connected to the second voltage dividing unit R2. The second voltage measuring circuit T2 may be used to detect the voltage across the second voltage dividing unit.

[0091] When the thermocouple does not suffer from thermal corrosion, such as when the thermocouple leaves the factory, the thermocouple thermal corrosion detection device can measure the thermocouple. When the thermocouple does not suffer from thermal corrosion, the thermocouple in a constant temperature environment is detected. For example, the thermoelectric potential generated by the thermocouple is detected. The control circuit can calculate the internal resistance of the thermocouple when thermal corrosion does not occur based on the voltage of the first voltage divider unit R1, the voltage of the second voltage divider unit R2, and the thermoelectric potential generated by the thermocouple obtained in this situation, and record it as the reference internal resistance. The reference internal resistance can be used to subsequently determine whether thermal corrosion occurs in the thermocouple.

[0092] In some examples, the thermocouple thermal corrosion detection device can exchange data or information with other devices so that the control circuit can receive the aforementioned status indication information, and the status indication information can indicate that the thermocouple is in a constant temperature environment. The control circuit can perform multiple measurements in response to the received status indication information. In each measurement, the control circuit can use the detection circuit to collect voltage signals. The control circuit can calculate the measured resistance value of the thermocouple based on the collected voltage signal. Thus, the control circuit can calculate multiple measured resistance values. In an embodiment of the present application, the measured resistance of the thermocouple includes the multiple measured resistance values. The control circuit can compare the measured resistance values ​​and the reference internal resistance with each other to determine the thermal corrosion state of the thermocouple.

[0093] Exemplarily, the control circuit may perform the first measurement control at the first time t1 in response to receiving the status indication information. The control circuit may control the first switch S1 to be in the on state, the second switch S2 to be in the off state, and the third switch S3 to be in the off state. Then the control circuit may obtain the voltage V1_t1 of the first voltage divider unit R1 through the first voltage measuring circuit T1, which is also the voltage of the first voltage divider unit R1 corresponding to the first measurement control; the control circuit may obtain the voltage V2_t1 of the second voltage divider unit R2 through the second voltage measuring circuit T2, which is also the voltage of the second voltage divider unit R2 corresponding to the first measurement control.

[0094] The control circuit can calculate the measured resistance value of the thermocouple based on the voltage V1_t1 of the first voltage divider unit R1, the voltage V2_t1 of the second voltage divider unit R2, the first voltage divider unit R1 and the second voltage divider unit R2 corresponding to the first measurement control, and record it as the first measured resistance value. The first measured resistance value represents the internal resistance of the thermocouple calculated by the control circuit using the parameters obtained in the first measurement control. The control circuit can compare the calculated first measured resistance value with a pre-stored reference resistance value.

[0095] To improve the measurement accuracy, the control circuit performs the second measurement control at the second moment t2. The second moment t2 is after the first moment t1, and the duration between the second moment t2 and the first moment t1 is a preset duration. The control circuit can control the first switch S1 to be in an open circuit state, control the second switch S2 to be in an on state, and control the third switch S3 to be in an open circuit state. Then, the control circuit can obtain the voltage V1_t2 of the first voltage divider unit R1 through the first voltage measuring circuit T1, which is also the voltage of the first voltage divider unit R1 corresponding to the second measurement control. The control circuit can calculate the measured resistance value of the thermocouple based on the voltage V1_t2 of the first voltage divider unit R1, the first voltage divider unit, the third voltage divider unit and the stored thermoelectric potential generated by the thermocouple. It is recorded as the second measured resistance value. Among them, the second measured resistance value represents the internal resistance of the thermocouple calculated by the control circuit using the parameters obtained in the second measurement control.

[0096] Then, the control circuit performs the third measurement control at the third moment t3. The third moment t3 is after the second moment t2, and the duration between the third moment t3 and the second moment t2 is the preset duration. The control circuit can control the first switch S1 to be in an open circuit state, control the second switch S2 to be in an open circuit state, and control the third switch S3 to be in an on state. Then the control circuit can obtain the voltage V2_t3 of the second voltage divider unit R2 through the second voltage measuring circuit T2, which is also the voltage of the second voltage divider unit R2 corresponding to the third measurement control. The control circuit can calculate the measured resistance value of the thermocouple based on the voltage V2_t3 of the second voltage divider unit R2, the second voltage divider unit, the fourth voltage divider unit and the stored thermoelectric potential generated by the thermocouple, and record it as the third measured resistance value. Among them, the third measured resistance value represents the internal resistance of the thermocouple calculated by the control circuit using the parameters obtained in the third measurement control. The control circuit can compare the calculated third measured resistance value with the pre-stored reference resistance value.

[0097] The control circuit can compare the first measured resistance value, the second measured resistance value and the third measured resistance value respectively calculated in the three measurement controls with the reference resistance value to determine whether thermal corrosion occurs to the thermocouple.

[0098] In some examples, if the first measured resistance value, the second measured resistance value, and the third measured resistance value are inconsistent, it may reflect the presence of an interference signal that affects the measurement, and the control circuit may re-execute the operations in the first measurement control, the second measurement control, and the third measurement control.

[0099] If at least two of the first measured resistance value, the second measured resistance value, and the third measured resistance value are equal and inconsistent with the reference resistance value, the control circuit may determine that thermal corrosion occurs in the thermocouple.

[0100] If at least two of the first measured resistance value, the second measured resistance value, and the third measured resistance value are equal and consistent with the reference resistance value, the control circuit can determine that the thermocouple has not been thermally corroded.

[0101] In some possible application scenarios, the control circuit can perform any one of the three measurement controls mentioned above. The control circuit can compare the measured resistance value of the thermocouple calculated in the one measurement operation with the reference internal resistance to determine whether thermal corrosion occurs in the thermocouple.

[0102] In some other possible application scenarios, the control circuit can perform any two of the three measurement controls mentioned above. The control circuit can compare the measured resistance of the thermocouple calculated in the two measurement operations with the reference internal resistance to determine whether thermal corrosion occurs in the thermocouple. For example, the two measurement control operations can be the first measurement control and the second measurement control, or the first measurement control and the third measurement control, or the second measurement control and the third measurement control. Figure 8 A possible implementation of the detection circuit provided is to combine Figure 9b The control circuit may include a current measuring circuit. The current measuring circuit is connected to the first connection terminal D1 of the detection circuit. Alternatively, the current measuring circuit is connected to the second connection terminal D2. The current measuring circuit can detect the current generated by the thermocouple.

[0103] When the thermocouple does not suffer from thermal corrosion, such as when the thermocouple leaves the factory, the thermocouple thermal corrosion detection device can measure the thermocouple. When the thermocouple does not suffer from thermal corrosion, the thermocouple in a constant temperature environment is detected. The control circuit can record the current obtained in this situation as a reference current, and the control circuit can calculate the resistance of the thermocouple based on the reference current, which is recorded as a reference resistance. The reference resistance can be used to subsequently determine whether the thermocouple suffers from thermal corrosion.

[0104] The thermocouple thermal corrosion detection device can exchange data or information with other devices. The control circuit can respond to receiving the status indication information and perform the first measurement control at the first time t1. The control circuit can control the first switch S1 to be in the on state, control the second switch S2 to be in the off state, and control the third switch S3 to be in the off state. The control circuit can obtain the current generated by the thermocouple in the first measurement control through the current measuring circuit. The control circuit can calculate the internal resistance of the thermocouple based on the current obtained in the first measurement control, the first voltage divider unit R1, the second voltage divider unit R2, and the stored thermoelectric potential of the thermocouple, and record it as the first measured resistance value.

[0105] Then, the control circuit performs the second measurement control at the second moment t2. The control circuit can control the first switch S1 to be in an open circuit state, control the second switch S2 to be in an on state, and control the third switch S3 to be in an open circuit state. The control circuit can obtain the current generated by the thermocouple in the second measurement control through the current measuring circuit. The control circuit can calculate the internal resistance of the thermocouple based on the current obtained in the second measurement control, the first voltage divider unit R1, the third voltage divider unit R3, and the stored thermoelectric potential of the thermocouple, and record it as the second measured resistance value.

[0106] Then, the control circuit performs the third measurement control at the third time t3. The control circuit can control the first switch S1 to be in an open circuit state, control the second switch S2 to be in an open circuit state, and control the third switch S3 to be in an on state. The control circuit can obtain the current generated by the thermocouple in the third measurement control through the current measuring circuit. The control circuit can calculate the internal resistance of the thermocouple based on the current obtained in the third measurement control, the second voltage divider unit R2, the fourth voltage divider unit R4, and the stored thermoelectric potential of the thermocouple, and record it as the third measured resistance value.

[0107] Similarly, the control circuit can compare the first measured resistance value, the second measured resistance value and the third measured resistance value respectively calculated in the three measurement controls with the pre-stored reference resistance value. For details, please refer to the relevant introduction in the above embodiment, which will not be repeated here.

[0108] Based on the same inventive concept, the present application also provides a thermocouple thermal corrosion detection method, which can be applied to any thermocouple thermal corrosion detection device provided in the present application. Fig.10 , the thermocouple thermal corrosion detection method may include the following steps:

[0109] S1001, measuring and obtaining a reference internal resistance of the thermocouple in a constant temperature environment without thermal corrosion.

[0110] In specific implementation, the operation of S1001 may be performed once. After measuring the reference internal resistance of the thermocouple, the thermocouple thermal corrosion detection device may store the reference internal resistance for subsequent determination of whether thermal corrosion occurs in the thermocouple.

[0111] S1002, collecting a voltage signal or a current signal using the detection circuit in a constant temperature environment; the control circuit calculates a measured resistance of the thermocouple based on the voltage signal or the current signal, compares the measured resistance with the reference internal resistance, and determines a thermal corrosion state of the thermocouple.

[0112] In specific implementation, the thermocouple thermal corrosion detection device can measure the internal resistance of the thermocouple in a constant temperature environment, and compare the measured resistance with the reference internal resistance to determine whether thermal corrosion occurs in the thermocouple.

[0113] In one possible design, the control circuit controls the detection circuit to obtain at least one of the voltage signals at at least one moment, and calculates at least one of the measured resistances based on the obtained voltage signals, wherein the at least one measured resistance includes one or more of a first measured resistance value, a second measured resistance value, and a third measured resistance value; the at least one measured resistance and the reference internal resistance are compared with each other to determine whether the thermocouple is corroded.

[0114] In some examples, the detection circuit includes a first voltage divider unit, a second voltage divider unit, and a first switch; at a first moment, the control circuit is used to control the first switch to be in an on state, and obtain a first voltage of the first voltage divider unit and a second voltage of the second voltage divider unit; and a first measured resistance value of the thermocouple is calculated based on the first voltage and the second voltage.

[0115] In some examples, the detection circuit further includes a first branch, the first branch includes a second switch and a third voltage dividing unit connected in series, and the first voltage dividing unit is grounded through the first branch;

[0116] At a second moment after the first moment, the control circuit is used to control the first switch to be in an open state and the second switch to be in an on state; a third voltage of the first voltage divider unit is obtained, and a second measured resistance value of the thermocouple is calculated based on the third voltage.

[0117] In some examples, the detection circuit further includes a second branch, the second branch includes a third switch and a fourth voltage dividing unit connected in series, and the second voltage dividing unit is grounded through the first branch;

[0118] At a third moment after the second moment, the control circuit is used to control the first switch to be in an open state, the second switch to be in an open state, and the third switch to be in an on state; a fourth voltage of the second voltage divider unit is obtained, and a third measured resistance value of the thermocouple is calculated based on the fourth voltage.

[0119] Based on the same inventive concept, an embodiment of the present application also provides a semiconductor manufacturing equipment, which may include a thermocouple and any one of the thermocouple thermal corrosion detection devices provided in the embodiments of the present application.

[0120] The semiconductor manufacturing equipment in this embodiment can be a machine used in the process. The present application can regularly detect the thermal corrosion state of the thermocouple according to the signal change of the machine state; the control detection time is short and will not affect the process and the temperature control of the machine; in the absence of an external power supply, only the potential difference of the thermocouple itself is used, and its potential is small, which has almost no effect on the display and control of the temperature; at the same time, the present application measures the resistance value of the thermocouple in a fixed state, and can judge the thermal corrosion state of the thermocouple according to the change of the measured resistance value of the thermocouple for a long time. After the resistance value of the thermocouple changes beyond a certain range, the thermocouple can be replaced in advance, avoiding the adverse effects of the thermal corrosion of the thermocouple on the production of the product in the actual process.

[0121] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A thermocouple thermal corrosion detection device, characterized in that: include: Detection circuit and control circuit; The detection circuit includes a first connection end and a second connection end; the first connection end is used to connect to a first cold end of a thermocouple, and the second connection end is used to connect to a second cold end of the thermocouple; The control circuit is used to obtain a voltage signal or a current signal in the detection circuit in response to received status indication information, and the status indication information indicates that the thermocouple is in a constant temperature environment.

2. The device according to claim 1, characterized in that The detection circuit includes a first voltage dividing unit, a second voltage dividing unit and a first switch; wherein the first connection end, the first voltage dividing unit, the first switch, the second voltage dividing unit and the second connection end are connected in series in sequence.

3. The device according to claim 2, characterized in that The control circuit includes a first pressure measuring circuit and a second pressure measuring circuit, wherein the first pressure measuring circuit is used to detect the voltage of the first voltage dividing unit, and the second pressure measuring circuit is used to detect the voltage of the second voltage dividing unit.

4. The device according to claim 3, characterized in that The detection circuit also includes a third connection end and a first branch, the third connection end is used to connect to the ground end, one end of the first branch is connected to the first end of the first voltage dividing unit, and the other end of the first branch is connected to the third connection end; the first end of the first voltage dividing unit is an end of the first voltage dividing unit connected to the first switch; the first branch includes a second switch and a third voltage dividing unit connected in series.

5. The device according to claim 4, characterized in that The detection circuit also includes a second branch; one end of the second branch is connected to the first end of the second voltage dividing unit, and the other end of the second branch is connected to the third connection end; the first end of the second voltage dividing unit is an end of the second voltage dividing unit connected to the first switch; the second branch includes a third switch and a fourth voltage dividing unit connected in series.

6. A semiconductor manufacturing equipment, characterized in that: It comprises a thermocouple and a thermocouple thermal corrosion detection device as described in any one of claims 1-5.

7. A thermocouple thermal corrosion detection method based on the thermocouple thermal corrosion detection device according to any one of claims 1 to 5, characterized in that: The method comprises: measuring and obtaining a reference internal resistance of the thermocouple in a constant temperature environment without thermal corrosion; collecting a voltage signal or a current signal using the detection circuit in the constant temperature environment; the control circuit calculating the measured resistance of the thermocouple based on the voltage signal or the current signal, comparing the measured resistance with the reference internal resistance, and determining the thermal corrosion state of the thermocouple.

8. The method according to claim 7, characterized in that The control circuit controls the detection circuit to obtain at least one of the voltage signals at at least one moment, and calculates at least one of the measured resistances based on the obtained voltage signals, wherein the at least one measured resistance includes one or more of a first measured resistance value, a second measured resistance value, and a third measured resistance value; and compares the at least one measured resistance and the reference internal resistance with each other to determine whether the thermocouple is corroded.

9. The method according to claim 8, characterized in that The detection circuit includes a first voltage divider unit, a second voltage divider unit and a first switch; at a first moment, the control circuit is used to control the first switch to be in an on state, and obtain a first voltage of the first voltage divider unit and a second voltage of the second voltage divider unit; and the first measured resistance value of the thermocouple is calculated based on the first voltage and the second voltage.

10. The method according to claim 9, characterized in that The detection circuit further includes a first branch, the first branch includes a second switch and a third voltage dividing unit connected in series, and the first voltage dividing unit is grounded through the first branch; At a second moment after the first moment, the control circuit is used to control the first switch to be in an open state and the second switch to be in an on state; a third voltage of the first voltage divider unit is obtained, and a second measured resistance value of the thermocouple is calculated based on the third voltage.

11. The method according to claim 10, characterized in that The detection circuit further includes a second branch, the second branch includes a third switch and a fourth voltage dividing unit connected in series, and the second voltage dividing unit is grounded through the first branch; At a third moment after the second moment, the control circuit is used to control the first switch to be in an open state, the second switch to be in an open state, and the third switch to be in an on state; a fourth voltage of the second voltage divider unit is obtained, and a third measured resistance value of the thermocouple is calculated based on the fourth voltage.

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