Method for automatically placing liquid opening distance of Czochralski crystal growing furnace

Abstract

The invention discloses a method for automatically placing a liquid port distance of a Czochralski single crystal furnace, which comprises the following steps of: calculating the liquid level height difference of silicon liquid in a crucible according to the charging quantity in the crucible at the current charging frequency and the previous charging quantity, and calculating the lower limit position to which the crucible needs to descend at present; when it is detected that the crucible descends to the lower limit position, the water cooling screen is triggered to descend to make contact with an inner guide supporting ring on the guide cylinder according to the descending speed; then comparing a current difference value between the current liquid opening distance and a preset target liquid opening distance, judging whether the current difference value is in, if not, controlling the crucible to rise according to the speed corresponding to the current difference value, and recalculating the current difference value after the crucible rises until the liquid opening distance position of the current charging frequency is completed; the distance between the crucible and the guide cylinder is automatically adjusted by controlling the descending speed of the water cooling screen and the ascending speed of the crucible, so that the liquid opening distance position is automatically determined, the liquid opening distance is automatically placed, manpower is saved, and the working efficiency and safety are improved.

Description

Technical Field

[0001] This invention relates to the field of Czochralski single crystal production technology, specifically to a method for automatically adjusting the liquid outlet distance in a Czochralski single crystal furnace. Background Technology

[0002] In the Czochralski method for single crystal growth, the distance from the lower edge of the flow guide tube to the surface of the molten silicon in the crucible is called the liquid gate distance. The size of the liquid gate distance directly affects the temperature gradient of the thermal field, and thus affects the crystal formation of the single crystal. During the single crystal production process, when transitioning from the chemical mixing to the welding process, since the welding requires the insertion of a seed crystal, the flow guide tube needs to be manually placed on the crucible before welding. The initial liquid gate distance position is then manually confirmed. After the initial liquid gate distance position is confirmed manually, the system accurately adjusts the liquid gate distance position during the crystal pulling process using a reflection method based on the set value.

[0003] When manually confirming the initial nozzle distance, workers need to visually inspect the distance inside the furnace and manipulate the crucible for placement, which is inefficient and dangerous. Therefore, automatically determining the nozzle distance before welding is a problem that needs to be solved. Summary of the Invention

[0004] The purpose of this invention is to provide a method and system for automatically placing the liquid outlet distance in a Czochralski single crystal furnace. By controlling the descent speed of the water-cooled screen and the ascent speed of the crucible, the distance between the crucible and the guide tube is automatically adjusted, thereby automatically determining the liquid outlet distance position, realizing automatic placement of the liquid outlet distance, saving manpower, and improving work efficiency and safety.

[0005] To achieve the above objectives, the following plan is adopted: On one hand, the present invention provides a method for automatically adjusting the liquid outlet distance in a Czochralski single crystal furnace, specifically including the following steps: S1. Obtain the current feeding number and the amount of material loaded. Calculate the height difference of the silicon liquid in the crucible based on the current feeding number and the amount of material loaded in the crucible and the previous feeding amount. Calculate the lower limit position to which the crucible needs to be lowered based on the height difference of the liquid level. S2. Detect the liquid percentage of molten silicon in the crucible during the current feeding cycle to determine whether melting is complete. When melting is complete, control the crucible to descend to the lower limit position. S3. When the crucible is detected to have descended to the lower limit position, the water-cooled screen is triggered to descend at a decreasing speed until it contacts the inner guide support ring on the guide tube. S4. After detecting that the water-cooled screen is in place, calculate the current liquid outlet distance based on the reflection of the CCD image measured by the camera installed above the guide tube. S5. Compare the current difference between the current liquid outlet distance and the preset target liquid outlet distance. Determine if the current difference is within the range. If not, control the crucible to rise at the speed corresponding to the current difference. After the crucible rises, recalculate the current difference. Repeat the above steps until the current difference is within the preset difference range, and complete the placement of the liquid outlet distance for the current feeding number.

[0006] In some specific implementations, the process of calculating the lower limit position to which the crucible needs to be lowered in step S1 is as follows: S11. Calculate the material quantity difference based on the current amount of material in the crucible and the previous amount of material. S12. Obtain the preset crucible size parameters and silicon liquid density, and calculate the difference in liquid level height of silicon liquid in the crucible between the two feeding operations based on the material quantity difference. S13. Obtain the lower limit position of the crucible corresponding to the previous feeding number, and increase the height corresponding to the liquid level height difference based on the previous lower limit position to obtain the current lower limit position to which the crucible needs to be lowered.

[0007] In some specific implementations, step S2 determines whether the melting process is complete by detecting the ratio of liquid to molten material in the crucible. When the liquid content is greater than 90% and remains so for 3 minutes, the melting process is considered complete.

[0008] In some specific implementation schemes, the process of the water-cooled screen descending at a decreasing rate in step S3 is as follows: S31. When the crucible is detected to have fallen to the lower limit position, the water-cooled screen is triggered to fall to the first position at the first speed and the first height. S32. When the water-cooled screen is detected to descend to the first position at the first height, the water-cooled screen is controlled to descend at the second speed, and the second height of the water-cooled screen from the lower edge to the preset lower limit position of the water-cooled screen is monitored in real time. S33. When the second height meets the preset threshold, control the water-cooled screen to descend at the third speed until it contacts the inner guide support ring on the guide tube.

[0009] In some specific implementation schemes, step S4, after detecting that the water-cooled screen is in place, also includes controlling the water-cooled screen to rise to a preset height.

[0010] In some specific implementations, the process of controlling the crucible to rise at the speed corresponding to the current difference in step S5 is as follows: S51. Determine whether the current difference exceeds the preset difference threshold. If so, control the crucible to automatically rise to the height corresponding to the preset difference threshold at the first rising speed to the first measurement position. S52. Recalculate the liquid outlet distance of the crucible at the first measurement position and compare the current difference between the liquid outlet distance and the target liquid outlet distance. S53. Repeat steps S51-S52 until the current difference is less than or equal to the preset difference threshold, then control the crucible to rise to the height corresponding to the current difference at the second rising speed to the second measurement position. S54. Recalculate the liquid outlet distance of the crucible at the second measurement position. When the current difference between the liquid outlet distance and the target liquid outlet distance is within the preset difference range, complete the placement of the liquid outlet distance position for the current feeding number.

[0011] In some specific implementations, in step S51, when the crucible rises to the first measurement position, the crucible is controlled to remain at the first measurement position for a preset time, and step S52 is executed within the preset time.

[0012] In some specific implementation schemes, the preset dwell time is set to 15 seconds.

[0013] In some specific implementation schemes, the preset height is set to 3mm.

[0014] In some specific implementation schemes, the process of detecting the water-cooled screen's positioning is as follows: when the water-cooled screen descends and comes into contact with the inner guide support ring on the guide tube, the inner guide support ring generates an upward supporting force on the water-cooled screen. The upper torque sensor installed on the guide tube senses the change in force and automatically stops the water-cooled screen from descending further, and the water-cooled screen is in position.

[0015] The beneficial effects of this invention are as follows: This invention calculates the liquid level in the crucible based on the amount of material added each time, and simultaneously links with the water-cooled screen. By controlling the distance between the water-cooled screen and the crucible, it automatically positions the initial position of the liquid outlet distance, achieving automatic placement of the liquid outlet distance. This saves manpower and improves work efficiency; it also improves the accuracy and uniformity of liquid outlet distance placement; and the unmanned operation enhances safety during liquid outlet distance placement, effectively preventing personnel injury. Attached Figure Description

[0016] Figure 1 This is a flowchart of the automatic liquid outlet spacing method for Czochralski single crystal provided in an embodiment of the present invention; Figure 2 This is a simplified schematic diagram of a single crystal furnace structure for automatically placing the liquid outlet distance for Czochralski single crystals, as provided in an embodiment of the present invention.

[0017] Figure label: 1-Water-cooled screen, 2-Flow guide tube, 3-Crucible, 4-Furnace lid, 5-Camera. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of the invention.

[0020] Furthermore, for clarity and brevity, descriptions of well-known functions and methods may have been omitted. Those skilled in the art will recognize that various changes and modifications can be made to the examples described herein without departing from the spirit and scope of this disclosure.

[0021] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0022] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0023] Example 1 This embodiment provides a method for automatically adjusting the liquid outlet distance in a Czochralski single crystal furnace, specifically including the following steps: S1. Obtain the current feeding number and the amount of material loaded. Calculate the height difference of the silicon liquid in the crucible based on the current feeding number and the amount of material loaded in the crucible and the previous feeding amount. Calculate the lower limit position to which the crucible needs to be lowered based on the height difference of the liquid level. The specific process for calculating the lower limit position to which the crucible needs to be lowered in step S1 is as follows: S11. Calculate the material quantity difference based on the current amount of material in the crucible and the previous amount of material. S12. Obtain the preset crucible size parameters and silicon liquid density, and calculate the difference in liquid level height of silicon liquid in the crucible between the two feeding operations based on the material quantity difference. S13. Obtain the lower limit position of the crucible corresponding to the previous feeding number, and increase the height corresponding to the liquid level height difference based on the previous lower limit position to obtain the current lower limit position to which the crucible needs to be lowered.

[0024] S2. Detect the liquid percentage of molten silicon in the crucible during the current feeding cycle to determine whether melting is complete. When melting is complete, control the crucible to descend to the lower limit position. Step S2 determines whether the melting process is complete by detecting the ratio of liquid to molten material in the crucible. When the liquid content is greater than 90% and remains so for 3 minutes, the melting process is considered complete.

[0025] S3. When the crucible is detected to have descended to the lower limit position, the water-cooled screen is triggered to descend at a decreasing speed until it contacts the inner guide support ring on the guide tube. The specific process of the water-cooled screen descending at a decreasing rate in step S3 is as follows: S31. When the crucible is detected to have fallen to the lower limit position, the water-cooled screen is triggered to fall to the first position at the first speed and the first height. S32. When the water-cooled screen is detected to descend to the first position at the first height, the water-cooled screen is controlled to descend at the second speed, and the second height of the water-cooled screen from the lower edge to the preset lower limit position of the water-cooled screen is monitored in real time. S33. When the second height meets the preset threshold, control the water-cooled screen to descend at the third speed until it contacts the inner guide support ring on the guide tube.

[0026] S4. After detecting that the water-cooled screen is in place, calculate the current liquid outlet distance based on the reflection of the CCD image measured by the camera installed above the guide tube. The process for detecting the water-cooled screen's positioning is as follows: When the water-cooled screen descends and contacts the inner guide support ring on the guide tube, the inner guide support ring exerts an upward supporting force on the water-cooled screen. The torque sensor installed on the guide tube detects the change in force and automatically stops the water-cooled screen from descending further, indicating that the water-cooled screen has positioned itself correctly. To prevent the water-cooled screen from descending too far and damaging the support ring, thus causing a safety accident, after detecting that the water-cooled screen has positioned itself correctly, the process also includes controlling the water-cooled screen to rise to a preset height (the preset height can be set to 3mm).

[0027] S5. Compare the current difference between the current liquid outlet distance and the preset target liquid outlet distance. Determine if the current difference is within the range. If not, control the crucible to rise at the speed corresponding to the current difference. After the crucible rises, recalculate the current difference. Repeat the above steps until the current difference is within the preset difference range, and complete the placement of the liquid outlet distance for the current feeding number.

[0028] First, place the water-cooled screen. After the screen is in place, the measured liquid outlet distance will fall into two categories: One is when the liquid surface of the crucible is close to the guide tube and within the camera's detection range. In this case, adjust the crucible position according to the current feed rate to adjust the liquid outlet distance. The other is when the water-cooled screen is in place but still far from the liquid surface and outside the camera's measurement range. In this case, the liquid outlet distance cannot be measured, and the distance to the target liquid outlet will definitely be greater than 5mm. Therefore, the crucible position needs to be adjusted. The specific process in step S5, controlling the crucible to rise at the speed corresponding to the current difference, is as follows: S51. Determine whether the current difference exceeds the preset difference threshold. If so, control the crucible to automatically rise to the height corresponding to the preset difference threshold at the first rising speed to the first measurement position. S52. When the crucible rises to the first measurement position, the crucible is controlled to stay at the first measurement position for a preset time, and the liquid outlet distance of the crucible at the first measurement position is recalculated within the preset time (e.g., the preset time is set to 15 seconds), and the current difference between the liquid outlet distance and the target liquid outlet distance is compared. S53. Repeat steps S51-S52 until the current difference is less than or equal to the preset difference threshold, then control the crucible to rise to the height corresponding to the current difference at the second rising speed to the second measurement position. S54. Recalculate the liquid outlet distance of the crucible at the second measurement position. When the current difference between the liquid outlet distance and the target liquid outlet distance is within the preset difference range, complete the placement of the liquid outlet distance position for the current feeding number.

[0029] It is understandable that, such as Figure 2 As shown, inside the single crystal furnace, from top to bottom, there is a water-cooled screen 1, a flow guide tube 2, and a crucible 3. The crucible 3 contains silicon solution. The flow guide tube 2 has an inner ring support ring, and an upper torque sensor is installed on the inner ring support ring to detect changes in the force of the inner ring support ring. After the water-cooled screen 1 is installed, its upper and lower limits are locked. This limit has a hard limit on the equipment and a soft limit in the system. The hard limit is locked before the furnace is disassembled and cannot be adjusted during crystal pulling. For example, after the upper limit is locked, the soft limit position will be recorded as 0. With the 0 starting point, the amount by which the water-cooled screen 1 descends will be recorded accordingly to control the speed. A camera 5 is installed on the furnace cover 4 of the single crystal furnace. Specifically, a hole is opened in the furnace cover 4 to allow the camera 5 to capture the view inside the furnace. The hole is fitted with quartz glass and gold-plated glass. The camera 5 captures images of the shooting points inside the furnace through this hole. After installing camera 5, camera 5 is calibrated so that it can capture images of the shooting points inside the furnace. In this way, the liquid outlet distance (from the lower edge of the guide tube 2 to the surface of the silicon liquid inside the crucible 3) can be calculated based on the reflection of the CCD image measured by camera 5 in the subsequent process.

[0030] In the process transition from material preparation to welding, welding requires multiple seed insertions, i.e., multiple feedings into the crucible. Therefore, at each feeding, the initial nozzle distance needs to be determined based on the current amount of material in the crucible. The difficulty in determining the initial nozzle distance lies in the fact that although the nozzle distance can be determined by reflection, the system inherently has a lag. Simply measuring and automatically placing the nozzle simultaneously can easily cause overshoot; for example, the target distance might be 20, but the actual distance might be 18 or smaller. This phenomenon can easily lead to silicon spraying safety accidents. Furthermore, neglecting to consider the varying material amounts that cause differences in the crucible liquid level, and ignoring the interaction with the water-cooling screen, can also lead to inconsistent nozzle distances if the water-cooling screen drops too far, potentially causing safety accidents. Therefore, the timing of the initial placement and how to automatically place the initial nozzle distance based on the line of sight are problems that need to be addressed.

[0031] To facilitate understanding and explanation of how this embodiment solves the above problems, the following is illustrated with specific examples: Let the first addition of material be R1, the second addition be R2, and the xth addition be RX; First feeding stage R1: Assuming a loading capacity of 950 kg, for the first loading, during the installation of the heating zone, the initial lower limit position of the crucible (position 0) is manually locked. Before loading, the target liquid nozzle distance for welding is set via parameters; this value serves as the final target value for automatic placement of the liquid nozzle distance. After the first loading, welding begins. The melting process is considered complete when the ratio of molten material to liquid in the crucible is detected. If the liquid percentage exceeds 90% and remains above 90% for 3 minutes, the melting process is considered complete. Before switching to the welding stage after melting is complete, the liquid nozzle distance is set. 1.1 After the melting process is complete, the crucible will be automatically lowered to the initial lower limit position (position 0 during the first feeding) at a speed of 100 mm / min. 1.2 After the crucible reaches the initial lower limit position, the water-cooled screen is triggered to descend at a speed of 200 mm / min (first speed). After descending 100 mm (first height), the speed automatically decreases to 100 mm / min (second speed). When the crucible is 30 mm away from the lower limit position of the water-cooled screen (second height), the descent speed decreases to 50 mm / min (third speed). The purpose of setting the above decreasing speed in this application is to prevent the water-cooled screen from descending too quickly, which could cause a delay in system recognition and lead to overdescent and safety accidents.

[0032] 1.3 When the water-cooled screen descends and contacts the inner guide support ring on the guide tube, the support ring generates an upward supporting force on the water-cooled screen. The torque sensor on the hot screen drive senses the change in force, automatically stops the water-cooled screen from descending further, and raises it 3mm. The purpose of this is to prevent the water-cooled screen from descending too far and damaging the support ring, thus avoiding a safety accident.

[0033] 1.4. Placing the liquid inlet distance: After the water-cooled screen is lowered to the set position, the difference between the liquid inlet distance value and the target liquid inlet distance is calculated based on the reflection of the CCD image measured by the camera. If the difference is greater than the preset difference threshold (5mm), the crucible begins to rise automatically at a rising speed of 50mm / min (first rising speed), rising 5mm, and then pausing for 15 seconds. During the pausing time, the difference between the liquid inlet distance value calculated based on the reflection of the CCD image measured by the camera and the target liquid inlet distance is calculated again, and the difference is compared again. This continues until the difference between the detected value and the calculated value is ≤5mm, at which point the system rises to the corresponding difference height at a speed of 20mm / min (second rising speed) and recalculates.

[0034] For example, assuming the target nozzle distance is 34mm and the camera detects a nozzle distance of 42mm, the difference is 8mm. The system then raises the crucible by 5mm and recalculates. At this point, the target nozzle distance is 34mm, and the camera detects a nozzle distance of 37mm. The system then automatically raises the crucible by another 3mm and recalculates the difference. Automatic nozzle placement is complete when the difference between the camera-detected nozzle distance and the calculated target nozzle distance is within the preset range (±1mm).

[0035] Second feeding stage R2: Assuming the second loading is 900 kg, similar to the first loading, the melting process is considered complete when the ratio of molten material to liquid in the crucible is detected. The liquid content is considered greater than 90% and remains so for 3 minutes. Before switching to the welding stage after melting is complete, the liquid outlet distance is adjusted. 2.1 Since this is the second addition, the crucible will not descend to the initial lower limit position (0) when the liquid outlet distance is initially set. Therefore, it is necessary to calculate the crucible lower limit position corresponding to the current addition based on the two addition amounts. Specifically, based on the pre-set crucible size parameters, the height of the silicon liquid in the crucible is automatically calculated according to the crucible size parameters and the silicon liquid density ρ = 2.53 g / cm3. For example: the crucible contains 950 kg of material in the first addition, and 900 kg after the second addition, a difference of Δm = 50 kg. The inner diameter of the crucible is 928 / 2 = 464 mm. Then, the height difference of the liquid level corresponding to 50 kg of silicon material is H = Δm / (ρ*π*r). 2 )*1000=50000 / (2.53*3.14*464*464)*1000=29.2mm; then when the liquid outlet distance is initially set, the crucible will not descend to position 0, and the descending position will be 29.2mm higher than the previous feeding amount.

[0036] 2.2 After performing the same steps as in step 1.2 of the first feeding R1 stage above, the water-cooled screen will automatically drop to the corresponding position. 2.3 Setting the liquid outlet distance: This step is the same as the liquid outlet distance setting step in step 1.4 of the first feeding R1 stage, and will not be repeated here. The liquid outlet distance will be set automatically in the end. The RX phase is calculated and placed sequentially according to the logic.

[0037] Additionally, it is important to note that during automatic adjustment, external interference should be avoided to prevent it from affecting the camera's detection accuracy, ensuring the accuracy and reliability of the liquid outlet distance detection data. If any abnormal alarm occurs during adjustment, operation should be stopped immediately, and the equipment status checked. The system should only be restarted after confirming that everything is correct.

[0038] Understandably, this application saves manpower and improves work efficiency; it also improves the accuracy and uniformity of liquid outlet spacing; and unmanned operation improves the safety of liquid outlet spacing and can effectively avoid personnel injury.

[0039] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Based on the technical essence of the present invention, any simple modifications, equivalent substitutions, and improvements made to the above embodiments within the spirit and principles of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A method for automatically adjusting the liquid outlet distance in a Czochralski single crystal furnace, characterized in that, Specifically, the following steps are included: S1. Obtain the current feeding number and the amount of material loaded. Calculate the height difference of the silicon liquid in the crucible based on the current feeding number and the amount of material loaded in the crucible and the previous feeding amount. Calculate the lower limit position to which the crucible needs to be lowered based on the height difference of the liquid level. S2. Detect the liquid percentage of molten silicon in the crucible during the current feeding cycle to determine whether melting is complete. When melting is complete, control the crucible to descend to the lower limit position. S3. When the crucible is detected to have descended to the lower limit position, the water-cooled screen is triggered to descend at a decreasing speed until it contacts the inner guide support ring on the guide tube. S4. After detecting that the water-cooled screen is in place, calculate the current liquid outlet distance based on the reflection of the CCD image measured by the camera installed above the guide tube. S5. Compare the current difference between the current liquid outlet distance and the preset target liquid outlet distance. Determine if the current difference is within the range. If not, control the crucible to rise at the speed corresponding to the current difference. After the crucible rises, recalculate the current difference. Repeat the above steps until the current difference is within the preset difference range, and complete the placement of the liquid outlet distance for the current feeding number.

2. The method for automatically adjusting the liquid outlet distance in a Czochralski single crystal furnace according to claim 1, characterized in that, The specific process for calculating the lower limit position to which the crucible needs to be lowered in step S1 is as follows: S11. Calculate the material quantity difference based on the current amount of material in the crucible and the previous amount of material. S12. Obtain the preset crucible size parameters and silicon liquid density, and calculate the difference in liquid level height of silicon liquid in the crucible between the two feeding operations based on the material quantity difference. S13. Obtain the lower limit position of the crucible corresponding to the previous feeding number, and increase the height corresponding to the liquid level height difference based on the previous lower limit position to obtain the current lower limit position to which the crucible needs to be lowered.

3. The method for automatically adjusting the liquid outlet distance in a Czochralski single crystal furnace according to claim 1, characterized in that, Step S2 determines whether the melting process is complete by detecting the ratio of liquid to molten material in the crucible. When the liquid content is greater than 90% and remains so for 3 minutes, the melting process is considered complete.

4. The method for automatically adjusting the liquid outlet distance in a Czochralski single crystal furnace according to claim 1, characterized in that, The specific process of the water-cooled screen descending at a decreasing rate in step S3 is as follows: S31. When the crucible is detected to have fallen to the lower limit position, the water-cooled screen is triggered to fall to the first position at the first speed and the first height. S32. When the water-cooled screen is detected to descend to the first position at the first height, the water-cooled screen is controlled to descend at the second speed, and the second height of the water-cooled screen from the lower edge to the preset lower limit position of the water-cooled screen is monitored in real time. S33. When the second height meets the preset threshold, control the water-cooled screen to descend at the third speed until it contacts the inner guide support ring on the guide tube.

5. The method for automatically adjusting the liquid outlet distance in a Czochralski single crystal furnace according to claim 1, characterized in that, Step S4, after detecting that the water-cooled screen is in place, also includes controlling the water-cooled screen to rise to a preset height.

6. The method for automatically adjusting the liquid outlet distance in a Czochralski single crystal furnace according to claim 1, characterized in that, The specific process of controlling the crucible to rise at the speed corresponding to the current difference in step S5 is as follows: S51. Determine whether the current difference exceeds the preset difference threshold. If so, control the crucible to automatically rise to the height corresponding to the preset difference threshold at the first rising speed to the first measurement position. S52. Recalculate the liquid outlet distance of the crucible at the first measurement position and compare the current difference between the liquid outlet distance and the target liquid outlet distance. S53. Repeat steps S51-S52 until the current difference is less than or equal to the preset difference threshold, then control the crucible to rise to the height corresponding to the current difference at the second rising speed to the second measurement position. S54. Recalculate the liquid outlet distance of the crucible at the second measurement position. When the current difference between the liquid outlet distance and the target liquid outlet distance is within the preset difference range, complete the placement of the liquid outlet distance position for the current feeding number.

7. The method for automatically setting the liquid outlet distance in a Czochralski single crystal furnace according to claim 6, characterized in that, In step S51, when the crucible rises to the first measurement position, the crucible is controlled to stay at the first measurement position for a preset time, and step S52 is executed within the preset time.

8. The method for automatically adjusting the liquid outlet distance in a Czochralski single crystal furnace according to claim 7, characterized in that, The preset dwell time is set to 15 seconds.

9. The method for automatically adjusting the liquid outlet distance in a Czochralski single crystal furnace according to claim 5, characterized in that, The default height is set to 3mm.

10. A method for automatically adjusting the liquid outlet distance in a Czochralski single crystal furnace according to claim 1, characterized in that, The process of detecting the water-cooled screen's positioning is as follows: When the water-cooled screen descends and contacts the inner guide support ring on the guide tube, the inner guide support ring generates an upward supporting force on the water-cooled screen. The upper torque sensor installed on the guide tube senses the change in force and automatically stops the water-cooled screen from descending further, thus the water-cooled screen is in position.

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