SiC high-temperature furnace tube equipment temperature control method and system

Abstract

This invention discloses a temperature control method and system for SiC high-temperature furnace tube equipment. The method includes the following steps: 1) Pre-acquiring the mapping relationship between the internal temperature value and the external temperature value of the furnace tube during the heating and holding process according to a preset temperature control curve; 2) Acquiring the external temperature value of the furnace tube, and obtaining the corresponding internal temperature value of the furnace tube based on the mapping relationship between the internal and external temperature values; 3) Using the internal temperature value of the furnace tube obtained in step 2) as the temperature control value, controlling the SiC high-temperature furnace tube equipment to heat up and hold according to the preset temperature control curve. This invention has the advantages of simple operation and precise temperature control.

Description

Technical Field

[0001] This invention mainly relates to the field of chip manufacturing technology, specifically to a temperature control method and system for SiC high-temperature furnace tube equipment. Background Technology

[0002] Due to its high power conversion efficiency and low power consumption, SiC chips are increasingly being used in new energy vehicles and photovoltaic fields. However, the gate oxide and activation processes for manufacturing SiC chips are inseparable from high-temperature furnace equipment. In high-temperature furnace equipment, the temperature control effect directly affects the quality of the process results.

[0003] To ensure accurate temperature control of the high-temperature furnace tube equipment, the applicant previously used a temperature compensation method as follows: using an external temperature measuring instrument (generally an infrared pyrometer) as control feedback, a temperature measuring instrument (generally a PROFILE TC) was inserted inside the furnace body, and the temperature was increased according to a predetermined process curve until the holding period, and the difference between the two was observed and written into the system for temperature compensation. The applicant found that this method has two problems: (1) if the equipment has multiple temperature zones, there will be temperature coupling between the temperature zones, and simply setting the difference cannot compensate well; (2) there is a time lag between the internal and external temperatures, and the lag cannot be solved by simple compensation. Therefore, setting the compensation value usually requires experienced engineers to try many times to find the optimal value, and this process varies from person to person.

[0004] Another method is to calibrate the process temperature in reverse based on the process results. This method requires a large amount of process data to support a correlation between the process results and the temperature. SiC wafers are expensive and not suitable for placing a large number of test pieces. Furthermore, the process results (such as sheet resistance) after processing by some furnace tube equipment are inconvenient to test. The process results can only be tested and known after a certain process is completed, and there is no condition for real-time compensation. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a simple and precise temperature control method and system for SiC high-temperature furnace tube equipment, which addresses the technical problems existing in the prior art.

[0006] To solve the above-mentioned technical problems, the technical solution proposed by this invention is as follows:

[0007] A temperature control method for SiC high-temperature furnace tube equipment includes the following steps:

[0008] 1) Pre-obtain the mapping relationship between the internal temperature value and the external temperature value of the furnace tube during the heating and heat preservation process according to the preset temperature control curve;

[0009] 2) Obtain the external temperature value of the furnace tube, and based on the mapping relationship between the internal temperature value of the furnace tube and the external temperature value of the furnace tube, obtain the corresponding internal temperature value of the furnace tube;

[0010] 3) Using the internal temperature value of the furnace tube obtained in step 2) as the temperature control value, control the SiC high-temperature furnace tube equipment to heat up and maintain the temperature according to the preset temperature control curve.

[0011] Preferably, the specific process of step 1) is as follows:

[0012] 1.1) Obtain the internal temperature value of the furnace tube and use it as the temperature control value to heat up and maintain the temperature according to the preset temperature control curve;

[0013] 1.2) During the heating and heat preservation process according to the preset temperature control curve, the external temperature value of the furnace tube is obtained, and the mapping relationship between the internal temperature value of the furnace tube and the external temperature value of the furnace tube is established.

[0014] Preferably, the update frequency of the mapping relationship between the internal temperature value and the external temperature value of the furnace tube is consistent with the temperature control setting time.

[0015] Preferably, in step 1.1), the internal temperature value of the furnace tube is obtained by a thermocouple.

[0016] Preferably, the external temperature value of the furnace tube is obtained by an infrared pyrometer.

[0017] Preferably, in the preset temperature control curve, the temperature point is held for a certain period of time to reduce the difference between the temperature inside the furnace tube and the temperature outside the furnace tube.

[0018] The preset temperature range is 400-600℃.

[0019] The present invention also discloses a computer-readable storage medium having a computer program stored thereon, the computer program performing the steps of the method described above when run by a processor.

[0020] The present invention further discloses a temperature control system for SiC high-temperature furnace tube equipment, including a memory and a processor. The memory stores a computer program, which executes the steps of the method described above when run by the processor.

[0021] Compared with the prior art, the advantages of the present invention are as follows:

[0022] This invention involves pre-inserting an internal temperature measuring instrument into the furnace tube before placing the wafer. During the heating and holding process following a set process temperature curve, the internal temperature of the furnace tube is measured using this instrument. This measurement is then compared with the temperature measured by an external temperature measuring instrument to establish a time-dependent mapping relationship between the measured temperatures. During the actual process, the internal temperature measuring instrument is removed, and the external temperature measuring instrument is used as the control feedback value for temperature curve control, indirectly achieving the requirement that the furnace internal temperature follows the set temperature curve. Because the preset temperature control curve corresponding to the mapping relationship is identical to the actual process temperature control curve, the internal temperature of the furnace tube is strictly correlated during the actual process, ensuring accurate temperature control. Furthermore, the mapping relationship already establishes coupling relationships between temperature zones, thus resolving the problem of difficulty in setting appropriate compensation values ​​due to coupling between temperature zones. This invention's temperature control method is not only simple to operate but also ensures that the furnace internal temperature closely follows the process temperature control curve, guaranteeing accurate temperature control.

[0023] In order to ensure that the actual temperature inside the furnace tube can follow the set temperature, the present invention maintains the temperature at the preset temperature point (the temperature outside the furnace tube) for a certain period of time, so as to ensure that the temperature inside the furnace tube, especially at the bottom, can follow the set temperature, thereby reducing temperature lag and thus reducing the impact on the process. Attached Figure Description

[0024] Figure 1 This is a flowchart of an embodiment of the SiC high-temperature furnace tube equipment temperature control method of the present invention.

[0025] Figure 2 This is a diagram showing the installation structure of the furnace tube internal and external temperature measuring instrument of the present invention in an embodiment. Detailed Implementation

[0026] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0027] like Figure 1 As shown, the temperature control method for SiC high-temperature furnace tube equipment according to an embodiment of the present invention includes the following steps:

[0028] 1) Pre-obtain the mapping relationship between the internal temperature value and the external temperature value of the furnace tube during the heating and heat preservation process according to the preset temperature control curve;

[0029] 2) Obtain the external temperature value of the furnace tube, and based on the mapping relationship between the internal temperature value of the furnace tube and the external temperature value of the furnace tube, obtain the corresponding internal temperature value of the furnace tube;

[0030] 3) Using the internal temperature value of the furnace tube obtained in step 2) as the temperature control value, control the SiC high-temperature furnace tube equipment to heat up and maintain the temperature according to the preset temperature control curve.

[0031] Specifically, the process of step 1) is as follows:

[0032] 1.1) Obtain the internal temperature value of the furnace tube and use it as the temperature control value to heat up and maintain the temperature according to the preset temperature control curve;

[0033] 1.2) During the heating and heat preservation process according to the preset temperature control curve, the external temperature value of the furnace tube is obtained, and the mapping relationship between the internal temperature value of the furnace tube and the external temperature value of the furnace tube is established.

[0034] Currently, the ideal temperature control effect is that the measurement value of the furnace tube internal temperature measuring instrument can follow the set process temperature curve in real time. However, in actual process, it is inconvenient to place the furnace tube internal temperature measuring instrument (because wafers need to be placed inside the furnace tube in actual process, and the inserted furnace tube internal temperature measuring instrument will affect the placement of the wafers). Therefore, this invention pre-inserts the furnace tube internal temperature measuring instrument when no wafers are placed. During the heating and holding process according to the set process temperature curve, the furnace tube internal temperature measuring instrument measures the temperature value inside the furnace tube, and establishes a time-based mapping relationship between the temperature values ​​measured by the internal and external temperature measuring instruments during the heating and holding process by corresponding with the temperature value measured by the external temperature measuring instrument. During the actual process, the furnace tube internal temperature measuring instrument is removed, and the external temperature measuring instrument is used as the control feedback value when controlling the temperature curve, indirectly achieving the requirement that the furnace internal temperature follows the set temperature curve. Because the preset temperature control curve obtained in the above mapping process is the same as the temperature control curve corresponding to the actual process, the internal temperature value of the furnace tube is strictly corresponding during the actual process, thus ensuring the accuracy of temperature control. Furthermore, since the above mapping relationship already includes coupling relationships between temperature zones, it solves the problem of difficulty in setting appropriate compensation values ​​due to coupling between temperature zones. The temperature control method of this invention is not only simple to operate, but also enables the internal temperature of the furnace to closely follow the process temperature control curve, ensuring the accuracy of temperature control.

[0035] This invention also discloses a computer-readable storage medium storing a computer program thereon, which, when run by a processor, executes the steps of the method described above. This invention further discloses a temperature control system for SiC high-temperature furnace tube equipment, including a memory and a processor, wherein the memory stores a computer program, which, when run by a processor, executes the steps of the method described above. The medium and system of this invention, corresponding to the methods described above, also possess the advantages described above.

[0036] The method of the present invention will now be described with reference to the accompanying drawings and a complete specific embodiment:

[0037] like Figure 1 As shown, the temperature control method for SiC high-temperature furnace tube equipment according to an embodiment of the present invention includes the following steps:

[0038] (1) Insert a temperature measuring instrument into the furnace tube, and also install a temperature measuring instrument on the outside of the furnace tube;

[0039] (2) The temperature measurement value of the furnace tube is used as the control feedback value, and the temperature is raised and kept warm according to the preset temperature control curve.

[0040] (3) During the heating and heat preservation process according to the preset temperature control curve, obtain the time-based mapping relationship between the measured value of the temperature measuring instrument in the furnace tube and the temperature value of the temperature measuring instrument outside the furnace tube, and obtain the mapping table.

[0041] (4) Remove the temperature measuring instrument inserted into the furnace tube;

[0042] (5) Obtain the temperature value measured by the external temperature measuring instrument of the furnace tube, and obtain the temperature value in the furnace tube according to the mapping table in step (3), as the temperature control feedback value;

[0043] (6) When the temperature rises according to the preset curve, the temperature is controlled according to the temperature control feedback value.

[0044] like Figure 2 As shown, the SiC high-temperature furnace tube equipment includes an outer furnace body, a jacket, and furnace tubes. The process area is located inside the furnace tubes, while the heaters and external temperature measuring instruments are placed in the jacket. The SiC high-temperature furnace tube equipment has multiple temperature zones, each independently controlled. The temperature measuring instruments inserted inside the furnace tubes are typically PROFILE TC thermocouples, and the number and location of these thermocouples correspond to the number and location of the temperature zones in the equipment. The external temperature measuring instruments are typically infrared pyrometers, and the number and location of these infrared pyrometers correspond to the number and location of the temperature zones in the equipment. Specifically... Figure 2 As shown, there are three temperature zones. There is one PROFILE TC thermocouple (one PROFILE TC corresponds to three temperature measuring points) and three infrared pyrometers inside and outside the furnace tube, respectively. The temperature measuring points inside and outside the furnace tube correspond one-to-one.

[0045] When using the temperature measurement value of the temperature measuring instrument in the furnace tube as the control feedback value, or when using the temperature measurement value of the temperature measuring instrument outside the furnace tube as the control feedback value, it is necessary to first adjust the corresponding control PID and other parameters to ensure that the real-time temperature value can follow the temperature setpoint well during the heating process.

[0046] During the heating and holding process according to the preset temperature control curve, the time-dependent mapping relationship between the temperature values ​​of the temperature measuring instrument inside the furnace tube and the temperature measuring instrument outside the furnace tube is obtained. This mapping relationship time is consistent with the temperature control setting time. That is, if the temperature is set every 1 second during the control process, a mapping relationship between the temperature inside and outside the furnace tube is required every 1 second. In addition, under stable machine conditions, if the same temperature control curve is set, the mapping relationship between the temperature inside and outside the furnace tube is fixed. When the structure of the SiC high-temperature furnace tube equipment changes or the process temperature control curve changes, a new mapping relationship needs to be obtained to ensure the reliability of temperature control in subsequent actual processes.

[0047] Because there is a certain distance between the inside of the furnace tube and the heater, heat is transferred to the inside of the furnace tube via radiation, resulting in a significant lag. Therefore, to ensure that the actual temperature inside the furnace tube follows the set temperature, it is held at a preset temperature point (the temperature outside the furnace tube) for a certain period of time (the specific time depends on the actual situation, aiming to ensure the consistency of the temperature inside the furnace tube in as little time as possible). This ensures that the temperature inside the furnace tube, especially at the bottom, follows the set temperature, reducing temperature lag and thus minimizing the impact on the process. The preset temperature point is set to 500℃. Below 500℃, the lag between the actual temperature inside and outside the furnace tube has little impact on the process. However, above 500℃, the lag between the actual temperature inside the furnace tube and the set temperature increases with the furnace tube temperature, having a greater and greater impact on the process. Of course, in other embodiments, the preset temperature point is selected based on the actual situation, such as between 400-600℃.

[0048] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should be considered within the scope of protection of the present invention.

Claims

1. A temperature control method for SiC high-temperature furnace tube equipment, characterized in that, Including the following steps: 1) Pre-obtain the mapping relationship between the internal temperature value and the external temperature value of the furnace tube during the heating and holding process according to the preset temperature control curve; insert the internal temperature measuring instrument of the furnace tube in advance before placing the wafer, and measure the internal temperature value of the furnace tube through the internal temperature measuring instrument during the heating and holding process according to the set process temperature curve, and establish the time-based mapping relationship between the temperature values ​​measured by the internal and external temperature measuring instruments of the furnace tube during the heating and holding process by corresponding with the temperature values ​​measured by the external temperature measuring instrument of the furnace tube. 2) Obtain the external temperature value of the furnace tube, and based on the mapping relationship between the internal temperature value of the furnace tube and the external temperature value of the furnace tube, obtain the corresponding internal temperature value of the furnace tube; 3) Using the internal temperature value of the furnace tube obtained in step 2) as the temperature control value, control the SiC high-temperature furnace tube equipment to heat up and maintain the temperature according to the preset temperature control curve. During the actual process, the internal temperature measuring instrument of the furnace tube is taken out, and the external temperature measuring instrument of the furnace tube is used as the control feedback value when controlling the temperature curve, so as to indirectly realize the requirement that the internal temperature of the furnace body follows the set temperature curve.

2. The temperature control method for SiC high-temperature furnace tube equipment according to claim 1, characterized in that, The update frequency of the mapping relationship between the internal temperature value and the external temperature value of the furnace tube is consistent with the temperature control setting time.

3. The temperature control method for SiC high-temperature furnace tube equipment according to claim 1, characterized in that, The internal temperature of the furnace tubes is obtained using thermocouples.

4. The temperature control method for SiC high-temperature furnace tube equipment according to claim 1, 2, or 3, characterized in that, The external temperature of the furnace tubes is obtained using an infrared pyrometer.

5. The temperature control method for SiC high-temperature furnace tube equipment according to claim 1, 2, or 3, characterized in that, In the preset temperature control curve, the temperature point is held for a certain period of time to reduce the difference between the temperature inside the furnace tube and the temperature outside the furnace tube.

6. The temperature control method for SiC high-temperature furnace tube equipment according to claim 5, characterized in that, The preset temperature range is 400-600℃.

7. A computer-readable storage medium having a computer program stored thereon, characterized in that, The computer program, when run by a processor, performs the steps of the method as described in any one of claims 1 to 6.

8. A temperature control system for a SiC high-temperature furnace tube device, comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, The computer program, when run by a processor, performs the steps of the method as described in any one of claims 1 to 6.

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