Method for calibrating thermometer of epitaxial furnace

Abstract

The embodiment of the invention discloses a method for calibrating a thermometer of an epitaxial furnace, and the method comprises the steps: S1, preparing an epitaxial wafer at a reference vapor deposition temperature shown by the thermometer of the epitaxial furnace; s2, the resistivity corresponding to the epitaxial wafer is obtained; and S3, calibrating the thermometer according to the actual vapor deposition temperature corresponding to the resistivity.

Description

Technical Field

[0001] The disclosed embodiments relate to the field of semiconductor manufacturing technology, and more particularly to a method for calibrating a thermometer of an epitaxial furnace. Background Art

[0002] The epitaxial growth process is to use a polished wafer as a substrate to grow an epitaxial layer with controllable resistivity and thickness, and no crystal origin particles (COP) defects and oxygen precipitation on its surface under certain conditions. The epitaxial growth process mainly includes vacuum epitaxial deposition process, vapor phase epitaxial deposition process and liquid phase epitaxial deposition process. Among them, the vapor phase epitaxial deposition process is to obtain an epitaxial layer by reacting silicon source gas with hydrogen in a high temperature environment to generate silicon atoms and deposit the silicon atoms on the surface of the substrate, and at the same time, introduce doping gas to dope the epitaxial layer to obtain the required resistivity. Compared with polished wafers, epitaxial wafers have the characteristics of fewer surface defects and controllable resistivity, so they are widely used in highly integrated integrated circuit (IC) components and metal-oxide-semiconductor field-effect transistor (MOSFET) processes.

[0003] At present, epitaxial wafers are usually prepared by atmospheric pressure vapor phase epitaxial deposition process, and the vapor phase deposition temperature is usually in the range of 1100℃ and 1150℃. The vapor phase deposition temperature is a very critical parameter in the preparation of epitaxial wafers. Its change has an important impact on the generation of defects in the epitaxial layer and the flatness of the epitaxial layer. Therefore, it is necessary to reasonably monitor and control the vapor phase deposition temperature.

[0004] In view of this, how to accurately monitor the vapor deposition temperature is a technical problem that needs to be solved urgently. Summary of the invention

[0005] In view of this, the embodiments of the present disclosure are intended to provide a method for calibrating a thermometer of an epitaxial furnace; the thermometer of the epitaxial furnace can be accurately calibrated to accurately monitor and control the vapor deposition temperature.

[0006] The technical solution of the embodiment of the present disclosure is implemented as follows: The present disclosure provides a method for calibrating a thermometer of an epitaxial furnace, the method comprising: Step S1: preparing an epitaxial wafer at a reference vapor deposition temperature indicated by a thermometer of an epitaxial furnace; Step S2: obtaining the resistivity corresponding to the epitaxial wafer; Step S3: calibrating the thermometer according to the actual vapor deposition temperature corresponding to the resistivity.

[0007] In some examples, preparing the epitaxial wafer at a reference vapor deposition temperature indicated by a thermometer of the epitaxial furnace includes: At the multiple reference vapor deposition temperatures, a corresponding multiple epitaxial wafers are prepared respectively.

[0008] In some examples, calibrating the thermometer according to an actual vapor deposition temperature corresponding to the resistivity includes: Obtaining a temperature deviation value between the reference vapor deposition temperature corresponding to the resistivity and the actual vapor deposition temperature; The thermometer is calibrated according to the temperature deviation value.

[0009] In some examples, calibrating the thermometer according to an actual vapor deposition temperature corresponding to the resistivity includes: Fitting to obtain reference curves between corresponding multiple resistivities of the multiple epitaxial wafers and corresponding multiple reference vapor deposition temperatures; Fitting to obtain actual curves between the plurality of resistivities and corresponding plurality of actual vapor deposition temperatures; The thermometer is calibrated according to the reference curve and the actual curve.

[0010] In some examples, calibration of the thermometer is performed by adjusting the thermal emissivity of the thermometer.

[0011] In some examples, the thermometer includes a first sub-thermometer disposed above a reaction chamber of the epitaxial furnace and a second sub-thermometer disposed below the reaction chamber, and the method further includes: After the thermometer is calibrated, a calibration evaluation is performed based on a difference between reference vapor deposition temperatures respectively indicated by the first sub-thermometer and the second sub-thermometer in a vapor deposition reaction.

[0012] In some examples, when the difference is less than or equal to a threshold, it is determined that the calibration is completed; or When the difference is greater than the threshold, steps S1 to S3 are repeated to continue calibrating the thermometer.

[0013] In some examples, the reference vapor deposition temperature is in a range of 1100°C to 1150°C.

[0014] In some examples, during the process of preparing each of the plurality of epitaxial wafers, the same flow rate of doping gas is introduced into the reaction chamber of the epitaxial furnace, and the duration of introducing the doping gas is the same.

[0015] In some examples, the flow rate of the doping gas is 220 sccm to 240 sccm, and the duration of introducing the doping gas is 55 s to 70 s.

[0016] The embodiment of the present disclosure provides a method for calibrating a thermometer of an epitaxial furnace; in the present disclosure, an epitaxial wafer is first prepared at a reference vapor deposition temperature indicated by a thermometer of the epitaxial furnace. Since the vapor deposition temperature has a great influence on the resistivity of the epitaxial wafer, the reference vapor deposition temperature indicated by the thermometer is compared according to the actual vapor deposition temperature corresponding to the resistivity of the epitaxial wafer in the present disclosure, thereby calibrating the thermometer. Through this method, the reference vapor deposition temperature indicated by the calibrated thermometer can be closer to the actual vapor deposition temperature in the reaction chamber to accurately reflect the temperature distribution in the reaction chamber, and this method avoids the disassembly and installation of components in the reaction chamber, thereby avoiding the reduction in production capacity and frequent process verification caused by disassembly and assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A schematic diagram of the structure of an epitaxial furnace in the related art provided by an embodiment of the present disclosure; Figure 2 A flow chart of a method for calibrating a thermometer of an epitaxial furnace provided in an embodiment of the present disclosure; Figure 3 A schematic diagram of a reference curve between resistivity and reference vapor deposition temperature obtained by fitting and an actual curve between resistivity and actual vapor deposition temperature provided in an embodiment of the present disclosure. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings in the embodiments of the present disclosure.

[0019] It should be noted that, for the sake of clarity, not all features of a specific implementation are described and illustrated in the specification and drawings. Furthermore, in order to avoid unnecessary details that obscure the technical solution focused on by the present disclosure, only the device structure and method steps closely related to the technical solution of the present disclosure are described and illustrated in the specification and drawings, while other details that are not closely related to the technical content of the present disclosure and are known to those skilled in the art are omitted.

[0020] See also Figure 1 , which shows a schematic structural diagram of an epitaxial furnace 1 in the related art. The epitaxial furnace 1 may include: The base 10 is used to support the substrate W.

[0021] The support frame 20 is used to support the susceptor 10 and drive the susceptor 10 to rotate around the central axis X at a certain speed during the epitaxial growth process. During the rotation of the susceptor 10, the substrate W rotates around the central axis X together with the susceptor 10, that is, the substrate W remains stationary relative to the susceptor 10. Therefore, a small gap G is provided between the radial edge of the susceptor 10 and the preheating ring 10A.

[0022] The bell jar 30 includes an upper bell jar 30A and a lower bell jar 30B, and the upper bell jar 30A and the lower bell jar 30B together enclose a reaction chamber RC containing the base 10 and the support frame 20. The base 10 divides the reaction chamber RC into an upper reaction chamber RC1 and a lower reaction chamber RC2, and the substrate W is placed in the upper reaction chamber RC1. Generally, the gas pressure in the upper reaction chamber RC1 is slightly greater than the gas pressure in the lower reaction chamber RC2, so that the gas in the upper reaction chamber RC1 can enter the lower reaction chamber RC2 through the gap G.

[0023] It should be noted that the material of the upper bell jar 30A and the lower bell jar 30B is quartz.

[0024] The gas inlet 40 is used to transport reaction gas, such as silicon source gas such as SiHCl 3 and doping gas such as B 2 H 6 or PH 3 , into the upper reaction chamber RC1 .

[0025] The exhaust port 50 is used to discharge the reaction waste gas and by-products out of the reaction chamber RC.

[0026] A plurality of heating elements 60 are disposed at the periphery of the upper bell jar 30A and the lower bell jar 30B and are used to provide a high temperature environment for a vapor deposition reaction in the reaction chamber RC through the upper bell jar 30A and the lower bell jar 30B.

[0027] It should be noted that the temperature in the reaction chamber RC can be measured by a thermometer 70. The thermometer 70 is generally a high-temperature infrared thermometer. The thermometer 70 includes a first sub-thermometer 701 and a second sub-thermometer 702, wherein the first sub-thermometer 701 is arranged above the reaction chamber RC, and the second sub-thermometer 702 is arranged below the reaction chamber RC. In the specific implementation process, the first sub-thermometer 701 and the second sub-thermometer 702 are respectively used to monitor and feedback the temperature of the center position of the upper surface of the substrate W and the center position of the lower surface of the susceptor 10, and then adjust the temperature in the reaction chamber RC by controlling the power ratio of the heating component 60.

[0028] During the vapor deposition process, if the temperature in the reaction chamber RC changes, the epitaxial layer of the prepared epitaxial wafer may have defects such as slippage, and its flatness and resistivity may change. For example, after replacing the heating assembly 60 or the base 10 and other components, due to the change in the material or spatial position of the components, the thermometer 70 needs to be calibrated so that the reference vapor deposition temperature shown by the thermometer 70 matches the actual vapor deposition temperature in the reaction chamber RC.

[0029] In the related art, in order to avoid the cumbersome disassembly of the components in the epitaxial furnace 1, the temperature corresponding to when the power of the heating component 60 reaches a certain power is usually used as the reference vapor deposition temperature shown by the thermometer 70, and then the thermal emissivity of the thermometer 70 is adjusted so that the reading of the thermometer 70 reaches the reference vapor deposition temperature, and the reference vapor deposition temperature shown by the thermometer 70 is identified as the actual vapor deposition temperature in the reaction chamber RC. However, the heating component 60 may cause a deviation between the supplied power and the actual power due to the different actual use time. Therefore, after the heating component 60 has been used for a long time, its actual power cannot be accurately obtained. When the actual power of the heating component 60 is used to calibrate the thermometer 70, due to the deviation of the actual power of the heating component 60, the reference vapor deposition temperature shown by the calibrated thermometer 70 will also be deviated, which will affect the determination of the actual vapor deposition temperature in the reaction chamber RC, thereby affecting the various properties of the prepared epitaxial wafer.

[0030] In view of the above situation, how to provide a method for accurately calibrating the thermometer is of great significance for the production of epitaxial wafers. Specifically, see Figure 2 , which shows a method for calibrating a thermometer of an epitaxial furnace provided by an embodiment of the present disclosure, the method comprising: Step S1: preparing an epitaxial wafer at a reference vapor deposition temperature indicated by a thermometer of an epitaxial furnace; Step S2: obtaining the resistivity corresponding to the epitaxial wafer; Step S3: calibrating the thermometer according to the actual vapor deposition temperature corresponding to the resistivity.

[0031] It should be noted that when Figure 1 When the first sub-thermometer 701 and the second sub-thermometer 702 shown in FIG. 7 monitor the actual vapor deposition temperature in the reaction chamber RC, the first sub-thermometer 701 and the second sub-thermometer 702 need to be calibrated in the present disclosure.

[0032] In some examples, the reading of the first sub-thermometer 701 is used as a reference vapor deposition temperature.

[0033] In addition, in the specific implementation process, the first sub-thermometer 701 is used to monitor the temperature at the center of the upper surface of the substrate W, and the second sub-thermometer 702 is used to monitor the temperature at the center of the lower surface of the susceptor 10. In order to make the reference vapor deposition temperature shown by the first sub-thermometer 701 and the second sub-thermometer 702 more accurately reflect the actual vapor deposition temperature in the reaction chamber RC, the positions of the first sub-thermometer 701 and the second sub-thermometer 702 can be adjusted according to actual conditions in the specific implementation process. For example, by adjusting the position of the second sub-thermometer 702 so that the second sub-thermometer 702 can monitor the temperature at the center of the susceptor 10. Specifically, as Figure 1 As shown, when the position of the second sub-thermometer 702 is not properly set, the temperature measured by the second sub-thermometer 702 may be the temperature of the connecting rod 80 connected to the base 10, rather than the temperature at the center of the lower surface of the base 10.

[0034] In the present disclosure, an epitaxial wafer is first prepared at a reference vapor deposition temperature indicated by a thermometer 70 of an epitaxial furnace. Since the vapor deposition temperature has a great influence on the resistivity of the epitaxial wafer, the resistivity corresponding to the epitaxial wafer is obtained by testing in the present disclosure, and then the reference vapor deposition temperature indicated by the thermometer 70 is compared with the actual vapor deposition temperature corresponding to the resistivity of the epitaxial wafer, thereby calibrating the thermometer 70. This method enables the reference vapor deposition temperature indicated by the calibrated thermometer 70 to be closer to the actual vapor deposition temperature in the reaction chamber RC, so as to accurately reflect the temperature distribution in the reaction chamber RC, and this method avoids the disassembly and installation of components in the reaction chamber RC, thereby avoiding the reduction in production capacity and frequent process verification caused by disassembly and assembly.

[0035] for Figure 2 In some possible implementations of the technical solution shown, the epitaxial wafer is prepared at a reference vapor deposition temperature shown by a thermometer of the epitaxial furnace, including: At the above-mentioned reference vapor deposition temperatures, corresponding epitaxial wafers are prepared respectively.

[0036] In order to calibrate the thermometer 70 more accurately, in the specific implementation process, corresponding multiple epitaxial wafers are prepared respectively at multiple reference vapor deposition temperatures. Thus, the thermometer 70 can be calibrated according to the resistivity of the epitaxial wafers corresponding to different reference vapor deposition temperatures and the actual vapor deposition temperature corresponding to the resistivity, thereby reducing the calibration error and making the calibration result more accurate.

[0037] for Figure 2 In some possible implementations of the technical solution shown, the thermometer is calibrated according to the actual vapor deposition temperature corresponding to the resistivity, including: Obtaining a temperature deviation value between the reference vapor deposition temperature corresponding to the resistivity and the actual vapor deposition temperature; The above-mentioned thermometer is calibrated according to the above-mentioned temperature deviation value.

[0038] In some examples, after an epitaxial wafer is prepared and the resistivity of the epitaxial wafer is obtained only at a reference vapor deposition temperature indicated by the thermometer 70, the temperature deviation value between the actual vapor deposition temperature corresponding to the resistivity and the reference vapor deposition temperature can be obtained in the present disclosure, and then the thermometer 70 is calibrated according to the temperature deviation value. It can be understood that when the reference vapor deposition temperature is less than the actual vapor deposition temperature, it indicates that the reading corresponding to the thermometer 70 is too small, so the reading of the calibrated thermometer 70 is the sum of the value corresponding to the reference vapor deposition temperature and the temperature deviation value; when the reference vapor deposition temperature is greater than the actual vapor deposition temperature, it indicates that the reading corresponding to the thermometer 70 is too large, so the reading of the calibrated thermometer 70 is the difference between the value corresponding to the reference vapor deposition temperature and the temperature deviation value.

[0039] In other examples, after a plurality of corresponding epitaxial wafers are prepared at a plurality of reference vapor deposition temperatures indicated by the thermometer 70, the resistivity of the epitaxial wafers prepared at each reference vapor deposition temperature is obtained in a specific implementation process, and then the temperature deviation value is obtained according to the actual vapor deposition temperature corresponding to the resistivity of the epitaxial wafers prepared at each reference vapor deposition temperature and the corresponding reference vapor deposition temperature. It can be understood that in this case, there are multiple temperature deviation values, and the thermometer 70 is calibrated according to the multiple temperature deviation values ​​in a specific implementation process, specifically, for example, the thermometer 70 is calibrated according to the average value corresponding to the multiple temperature deviation values. That is to say, when the reading corresponding to the thermometer 70 is smaller, the reading of the calibrated thermometer 70 is the sum of the value corresponding to the reference vapor deposition temperature and the average value corresponding to the temperature deviation value; when the reading corresponding to the thermometer 70 is larger, the reading of the calibrated thermometer 70 is the difference between the value corresponding to the reference vapor deposition temperature and the average value corresponding to the temperature deviation value.

[0040] For the above-mentioned embodiments, in some examples, calibrating the above-mentioned thermometer according to the actual vapor deposition temperature corresponding to the above-mentioned resistivity includes: Fitting to obtain reference curves between corresponding multiple resistivities of the multiple epitaxial wafers and corresponding multiple reference vapor deposition temperatures; Fitting to obtain actual curves between the above multiple resistivities and corresponding multiple actual vapor deposition temperatures; The thermometer is calibrated according to the reference curve and the actual curve.

[0041] After a corresponding plurality of epitaxial wafers are prepared at a plurality of reference vapor deposition temperatures indicated by the thermometer 70, and the resistivity of the epitaxial wafers prepared at each reference vapor deposition temperature is obtained, a temperature deviation value is obtained based on the actual vapor deposition temperature corresponding to the resistivity of the epitaxial wafers prepared at each reference vapor deposition temperature and the corresponding reference vapor deposition temperature. It can be understood that in this case, there are multiple temperature deviation values. In order to ensure that the thermometer 70 can be accurately calibrated, in a specific implementation process, the corresponding multiple resistivities of the multiple epitaxial wafers are fitted with the corresponding multiple reference vapor deposition temperatures to obtain a corresponding reference curve, as shown in FIG. Figure 3 The multiple resistivities and the corresponding multiple actual vapor deposition temperatures are fitted to obtain the corresponding actual curves, as shown in FIG. Figure 3 As shown by the solid line in . It can be understood that after obtaining the reference curve and the actual curve, the thermometer 70 can be calibrated according to the offset between the reference curve and the actual curve as the temperature deviation value, so that the multiple reference vapor deposition temperatures shown by the calibrated thermometer 70 can be closer to the corresponding actual vapor deposition temperatures, that is, after obtaining the above-mentioned temperature deviation value, the thermometer 70 is calibrated to make the reference curve close to the actual curve.

[0042] for Figure 2 In the technical solution shown, in some examples, the calibration of the above-mentioned thermometer is performed by adjusting the thermal emissivity of the above-mentioned thermometer.

[0043] Thermometer 70 is usually a high-temperature infrared thermometer. The measurement of the high-temperature infrared thermometer is achieved through the relationship between the magnitude of infrared radiation energy and the surface temperature, and the thermal emissivity of the material made of the high-temperature infrared thermometer can reflect the infrared radiation characteristics of the high-temperature infrared thermometer. Specifically, the relationship between the thermal emissivity E of the high-temperature infrared thermometer and the temperature shown by the high-temperature infrared thermometer is expressed by the formula E=r / T, where r represents a constant. Therefore, by changing the thermal emissivity of the thermometer 70, different reference vapor deposition temperatures can be shown. Based on this, in the embodiment of the present disclosure, the reading of the thermometer 70 is adjusted by adjusting the thermal emissivity of the thermometer 70.

[0044] for Figure 2 In some possible implementations of the technical solution shown, the thermometer includes a first sub-thermometer disposed above the reaction chamber of the epitaxial furnace and a second sub-thermometer disposed below the reaction chamber, and the method further includes: After the thermometer is calibrated, a calibration evaluation is performed based on the difference between the reference vapor deposition temperatures respectively indicated by the first sub-thermometer and the second sub-thermometer during the vapor deposition reaction.

[0045] It should be noted that the calibration of the thermometer 70 in the above technical solution includes the calibration of the first sub-thermometer 701 and the second sub-thermometer 702. After the calibration of the thermometer 70 is completed, the calibration result still needs to be evaluated during the specific implementation process. In the present disclosure, after the thermometer 70 is calibrated, the vapor deposition process is continued to be performed, thereby obtaining the reference vapor deposition temperatures respectively shown by the first sub-thermometer 701 and the second sub-thermometer 702, and obtaining the difference between the reference vapor deposition temperatures respectively shown by the first sub-thermometer 701 and the second sub-thermometer 702, so as to evaluate the calibration result. Specifically, in some examples, when the above difference is less than or equal to a threshold value, it is determined that the above calibration is completed; or When the difference is greater than the threshold, steps S1 to S3 are repeated to continue calibrating the thermometer.

[0046] The above threshold value can be determined according to actual conditions. For example, when the threshold value is 3°C, when the above difference is less than or equal to 3°C, it indicates that the calibration of the thermometer 70 is completed. On the contrary, when the above difference is greater than 3°C, it indicates that the reading of the thermometer 70 still needs to be adjusted by adjusting the thermal emissivity of the thermometer 70. The specific method is still performed by repeatedly executing steps S1 to S3 of the above technical solution.

[0047] It should be noted that when the above difference is greater than the above threshold, it indicates that the temperature distribution in the reaction chamber is uneven, which may cause a large temperature distribution difference between the upper reaction chamber and the lower reaction chamber, and further heat transfer may occur between the upper reaction chamber RC1 and the lower reaction chamber RC2 during the vapor deposition process, thereby causing the temperature distribution in the upper reaction chamber where the substrate W is located to change, ultimately affecting the preparation process of the epitaxial layer.

[0048] for Figure 2 In the technical solution shown, in some possible implementations, the above-mentioned reference vapor deposition temperature is in the range of 1100°C to 1150°C.

[0049] In some examples, when a plurality of corresponding epitaxial wafers are prepared at a plurality of reference vapor deposition temperatures, the plurality of reference vapor deposition temperatures are 1100° C., 1110° C., 1120° C., 1130° C., 1140° C., and 1150° C. Of course, in a specific implementation, the plurality of reference vapor deposition temperatures may also be other vapor deposition temperatures in the range of 1100° C. to 1150° C.

[0050] for Figure 2In the technical solution shown, in some possible implementations, during the process of preparing each of the plurality of epitaxial wafers, the same flow rate of doping gas is introduced into the reaction chamber of the epitaxial furnace, and the duration of introducing the doping gas is the same. Optionally, the flow rate of the doping gas is 220 sccm to 240 sccm, and the duration of introducing the doping gas is 55 s to 70 s.

[0051] In order to ensure that the thermometer 70 can be accurately calibrated, in the specific implementation process, during the preparation process of each of the above-mentioned multiple epitaxial wafers, the same flow rate of doping gas is introduced into the reaction chamber, and the duration of the introduction of the above-mentioned doping gas is the same, so as to ensure that each epitaxial wafer performs the doping process under the same doping conditions except for the different vapor deposition temperatures, thereby improving the consistency of the electrical properties and material quality of the epitaxial layer to ensure the calibration result of the thermometer 70.

[0052] It should be noted that the technical solutions described in the embodiments of the present disclosure can be combined arbitrarily without conflict.

[0053] The above is only a specific embodiment of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any person skilled in the art who is familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present disclosure, which should be included in the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be based on the protection scope of the claims.

Claims

1. A method for calibrating a thermometer of an epitaxial furnace, characterized in that: The method comprises: Step S1: preparing an epitaxial wafer at a reference vapor deposition temperature indicated by a thermometer of an epitaxial furnace; Step S2: obtaining the resistivity corresponding to the epitaxial wafer; Step S3: calibrating the thermometer according to the actual vapor deposition temperature corresponding to the resistivity.

2. The method for calibrating a thermometer of an epitaxial furnace according to claim 1, characterized in that: The step of preparing an epitaxial wafer at a reference vapor deposition temperature indicated by a thermometer of the epitaxial furnace comprises: At the multiple reference vapor deposition temperatures, a corresponding plurality of epitaxial wafers are prepared respectively.

3. The method for calibrating a thermometer of an epitaxial furnace according to claim 1 or 2, characterized in that: The step of calibrating the thermometer according to the actual vapor deposition temperature corresponding to the resistivity comprises: Obtaining a temperature deviation value between the reference vapor deposition temperature corresponding to the resistivity and the actual vapor deposition temperature; The thermometer is calibrated according to the temperature deviation value.

4. The method for calibrating a thermometer of an epitaxial furnace according to claim 2, characterized in that: The step of calibrating the thermometer according to the actual vapor deposition temperature corresponding to the resistivity comprises: Fitting to obtain reference curves between corresponding multiple resistivities of the multiple epitaxial wafers and corresponding multiple reference vapor deposition temperatures; Fitting to obtain actual curves between the plurality of resistivities and corresponding plurality of actual vapor deposition temperatures; The thermometer is calibrated according to the reference curve and the actual curve.

5. The method for calibrating a thermometer of an epitaxial furnace according to claim 1, characterized in that: The thermometer is calibrated by adjusting the thermal emissivity of the thermometer.

6. The method for calibrating a thermometer of an epitaxial furnace according to claim 1, characterized in that: The thermometer includes a first sub-thermometer disposed above a reaction chamber of the epitaxial furnace and a second sub-thermometer disposed below the reaction chamber, and the method further includes: After the thermometer is calibrated, a calibration evaluation is performed based on a difference between reference vapor deposition temperatures respectively indicated by the first sub-thermometer and the second sub-thermometer in a vapor deposition reaction.

7. The method for calibrating a thermometer of an epitaxial furnace according to claim 6, characterized in that: When the difference is less than or equal to a threshold, determining that the calibration is completed; or When the difference is greater than the threshold, steps S1 to S3 are repeated to continue calibrating the thermometer.

8. The method for calibrating a thermometer of an epitaxial furnace according to claim 1, characterized in that: The reference vapor deposition temperature is in the range of 1100°C to 1150°C.

9. The method for calibrating a thermometer of an epitaxial furnace according to claim 2, characterized in that: In the process of preparing each of the plurality of epitaxial wafers, the same flow rate of doping gas is introduced into the reaction chamber of the epitaxial furnace, and the duration of introducing the doping gas is the same.

10. The method for calibrating a thermometer of an epitaxial furnace according to claim 9, characterized in that: The flow rate of the doping gas is 220 sccm to 240 sccm, and the duration of introducing the doping gas is 55 s to 70 s.

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