Single crystal furnace liquid level distance control method and system, electronic equipment and storage medium

Abstract

The invention provides a single crystal furnace liquid level distance control method which comprises the following steps: before temperature stabilization, setting a liquid level distance as a standard liquid level distance; in the crystal pulling process, an inverted image of the guide cylinder is obtained; calculating the area of the inverted image of the guide cylinder according to the image; and controlling the liquid level distance to tend to the standard liquid level distance according to the change of the inverted image area of the guide cylinder. The device has the beneficial effects that the liquid level distance is controlled by monitoring the inverted image area of the guide cylinder, so that the monitoring is more accurate, and the control of the liquid level distance is more stable.

Description

Technical Field

[0001] The present invention belongs to the technical field of Czochralski single crystals, and in particular relates to a single crystal furnace liquid level control method, system, electronic equipment and storage medium. Background Art

[0002] In the process of growing single crystals by pulling them together, in order to ensure stable growth of the crystals, the distance between the liquid surface of the silicon liquid and the lower edge of the guide tube, i.e., the liquid surface distance, needs to be kept constant. In the prior art, an image monitoring device is usually installed on the cover of a single crystal furnace to photograph the edge of the lower edge of the guide tube and its reflection on the liquid surface, and the liquid surface distance is controlled by monitoring the change in the distance between the edge of the lower edge of the guide tube and its reflection. However, when the distance between the edge of the lower edge of the guide tube and its reflection is too small, accurate monitoring cannot be performed, resulting in the inability to control the liquid surface distance based on this distance. Summary of the invention

[0003] In order to solve the above technical problems, the present invention provides a single crystal furnace liquid level control method, system, electronic equipment and storage medium, which effectively solve the problems existing in the prior art.

[0004] The technical solution adopted by the present invention is: a method for controlling the liquid level of a single crystal furnace, comprising the steps of:

[0005] Before stabilizing the temperature, set the liquid level distance to the standard liquid level distance;

[0006] During the crystal pulling process, an image of the reflection of the guide tube is obtained;

[0007] Calculating the area of ​​the reflection of the guide tube according to the image;

[0008] According to the change of the area of ​​the reflection of the guide tube, the liquid surface distance is controlled to approach the standard liquid surface distance.

[0009] Furthermore, before the temperature is stabilized, the liquid level distance is set to the standard liquid level distance, including:

[0010] Before stabilizing the temperature, lower the liquid level detection object to the height of the standard liquid level distance;

[0011] The crucible is moved so that the liquid surface contacts the liquid level detection object.

[0012] Furthermore, before lowering the liquid level detection object, the liquid level detection object needs to be zero-calibrated.

[0013] Furthermore, the liquid level detection object is clamped by a weight chuck, and the zero position of the liquid level detection object is that the weight chuck is flush with the lower edge of the guide tube.

[0014] Further, the step calculates the area of ​​the reflection of the guide tube according to the image, and the reflection of the guide tube is an ellipse.

[0015] According to the image, measuring the length a of the major semi-axis of the ellipse;

[0016] Calculate the length b of the minor semi-axis of the ellipse;

[0017] The area is calculated based on the length a of the major semi-axis and the length b of the minor semi-axis.

[0018] Further, the step of calculating the length b of the minor semi-axis of the ellipse is:

[0019] Extract the coordinates (x, y) of the pick-up point on the ellipse;

[0020] According to the standard equation of the ellipse, the length b of the minor semi-axis is calculated.

[0021] Furthermore, the step controls the liquid surface distance to approach the standard liquid surface distance according to the change in the area of ​​the reflection of the guide tube, and adopts a self-correcting PID closed-loop control system to control the rise of the crucible by comparing the area of ​​the reflection of the guide tube with the initial area, so that the area of ​​the reflection of the guide tube approaches the initial area.

[0022] The present invention also provides a single crystal furnace liquid level control system, comprising:

[0023] Liquid level distance measurement module, used to set the liquid level distance to the standard liquid level distance before temperature stabilization;

[0024] An image acquisition module is used to acquire an image of the reflection of the guide tube during the crystal pulling process;

[0025] A calculation processing module, used for calculating the area of ​​the reflection of the guide tube according to the image;

[0026] A control module is used to control the liquid level distance to approach the standard liquid level distance according to the change of the area of ​​the reflection of the guide tube.

[0027] The present invention also provides an electronic device, comprising a memory, a processor, and one or more programs stored in the memory and executable on the processor. When the one or more programs are executed by the processor, the electronic device executes the single crystal furnace liquid level control method as described above.

[0028] The present invention also provides a computer-readable storage medium, on which computer instructions are stored. When the computer instructions are executed on a processor of an electronic device, the device where the computer storage medium is located executes the single crystal furnace liquid level control method as described above.

[0029] The advantages and positive effects of the present invention are as follows: due to the adoption of the above technical solution, the liquid level distance is controlled by monitoring the reflection area of ​​the guide tube, so that the monitoring is more accurate and the control of the liquid level distance is more stable. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic flow chart of a method for controlling liquid level of a single crystal furnace according to an embodiment of the present invention.

[0031] Figure 2 It is a schematic diagram of measuring a standard liquid level distance in a single crystal furnace liquid level distance control method according to an embodiment of the present invention.

[0032] Figure 3 It is a schematic diagram of the reflection of a guide tube in a method for controlling liquid level of a single crystal furnace according to an embodiment of the present invention.

[0033] In the figure:

[0034] 1. Liquid level detection object 2. Lifting device 3. Heavy hammer chuck

[0035] 4. Draft tube 5. Crucible 6. Liquid surface

[0036] 7. Reflection of the guide tube DETAILED DESCRIPTION

[0037] The embodiments of the present invention provide a single crystal furnace liquid level control method, system, electronic device and storage medium. The embodiments of the present invention are described below in conjunction with the accompanying drawings.

[0038] In the description of the embodiments of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "top", "bottom", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "set" and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0039] like Figure 1As shown, a method for controlling the liquid level distance of a single crystal furnace according to an embodiment of the present invention includes: S1, before temperature stabilization, setting the liquid level distance to a standard liquid level distance; S2, during the crystal pulling process, obtaining an image of the reflection of the guide tube; S3, calculating the area of ​​the reflection of the guide tube according to the image; S4, controlling the liquid level distance to tend toward the standard liquid level distance according to the change in the area of ​​the reflection of the guide tube. The liquid level distance is controlled by monitoring the reflection area of ​​the guide tube, thereby avoiding the defect in the prior art that the distance between the edge of the lower edge of the guide tube and its reflection is too small to be monitored, and making the control of the liquid level distance more stable. The following is a detailed description:

[0040] S1. Before stabilizing the temperature, set the liquid level distance to the standard liquid level distance;

[0041] The method includes lowering the liquid level detection object to a height of a standard liquid surface distance before stabilizing the temperature; and moving the crucible so that the liquid surface contacts the liquid level detection object.

[0042] like Figure 2 As shown, before temperature stabilization, a liquid level distance measuring module is used to set the liquid level distance to a standard liquid level distance. The liquid level distance measuring module includes a liquid level detection object 1. The specific form of the liquid level detection object 1 is not limited. It can be a liquid level probe or a seed crystal. The length of the liquid level detection object 1 is known to be L. The top of the liquid level detection object 1 is clamped by a heavy hammer chuck 3. The heavy hammer chuck 3 is provided with a lifting device 2, which can drive the liquid level detection object 1 to rise or fall. The lifting device 2 is provided with a displacement detection device, which can be used to measure the distance that the liquid level detection object 1 moves up and down.

[0043] First, lower the liquid level detection object 1 to zero position for zero position correction. The zero position of the liquid level detection object 1 is the position where the weight chuck 3 is flush with the lower edge of the guide tube 4. Through the displacement detection device, the liquid level detection object 1 can be accurately lowered to zero position. The standard liquid surface distance is set to d. After the lifting device 2 lowers the liquid level detection object 1 to zero position, it continues to lower the liquid level detection object 1 by dL. At this time, the position of the bottom of the liquid level detection object 1 is the height of the standard liquid surface distance. Move the crucible 5, and the contact between the liquid surface 6 and the liquid level detection object 1 can be detected by detecting the potential change of the liquid level detection object 1. When the liquid surface 6 contacts the bottom of the liquid level detection object 1, the liquid surface distance is the standard liquid surface distance. During the crystal pulling process, the liquid surface distance needs to be controlled to keep the standard liquid surface distance unchanged.

[0044] S2. During the crystal pulling process, obtaining an image of the reflection of the guide tube;

[0045] An image acquisition module is installed on the top of the furnace cover of the single crystal furnace to acquire the image of the reflection of the guide tube during the crystal pulling process. In this embodiment, the image acquisition module is specifically a CCD camera.

[0046] S3. Calculate the area of ​​the reflection of the guide tube according to the image;

[0047] like Figure 3 As shown, the reflection 7 of the guide tube is an ellipse. In the captured image, the major axis of the ellipse can be directly measured to obtain the length a of the major semi-axis.

[0048] Since the minor axis of the ellipse in the image is blocked and cannot be measured directly, the coordinates (x, y) of a pick-up point on the ellipse contour can be arbitrarily extracted. According to the standard equation of the ellipse x 2 / a 2 +y 2 / b 2 =1 and a, we can calculate the length b of the minor semi-axis of the ellipse.

[0049] According to the area formula of an ellipse S=a*b*π, the area of ​​an ellipse can be calculated.

[0050] When pulling the crystal, the initial area of ​​the ellipse is the standard area corresponding to the standard liquid level distance. The liquid level distance is controlled to remain unchanged. It is sufficient to keep the area of ​​the ellipse at the initial area, that is, the standard area.

[0051] S4. According to the change of the reflected area of ​​the guide tube, the liquid surface distance is controlled to approach the standard liquid surface distance.

[0052] A self-correcting PID closed-loop control system is adopted. By comparing the reflected area of ​​the guide tube with the initial area, if there is a difference between the two, the crucible is controlled to rise so that the reflected area of ​​the guide tube approaches the initial area, i.e. the standard area, and the liquid surface distance approaches the standard liquid surface distance.

[0053] A single crystal furnace liquid level control system, comprising:

[0054] Liquid level distance measurement module, used to set the liquid level distance to the standard liquid level distance before temperature stabilization;

[0055] An image acquisition module is used to acquire an image of the reflection of the guide tube during the crystal pulling process;

[0056] A calculation processing module, used for calculating the area of ​​the reflection of the guide tube according to the image;

[0057] The control module is used to control the liquid level distance to approach the standard liquid level distance according to the change of the reflection area of ​​the guide tube.

[0058] An electronic device includes a memory, a processor, and one or more programs stored in the memory and executable on the processor. When the one or more programs are executed by the processor, the electronic device executes the above-mentioned single crystal furnace liquid level control method.

[0059] A computer-readable storage medium stores computer instructions. When the computer instructions are executed on a processor of an electronic device, the device where the computer storage medium is located executes the above-mentioned single crystal furnace liquid level control method.

[0060] The above-mentioned functional modules can be integrated into one processing module, or each module can exist physically separately, or two or more modules can be integrated into one module. The above-mentioned integrated modules can be implemented in the form of hardware or in the form of software functional units.

[0061] If the integrated module is implemented in the form of a software functional unit, it can be stored in a computer-readable storage medium. The technical solution of the present application, in essence, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, server or network device, etc.) to execute all or part of the steps of the single crystal furnace liquid level control method described in the embodiments of the present application.

[0062] The aforementioned storage media include: U disk, mobile hard disk, read-only memory, random access memory, magnetic disk or optical disk and other media that can store program codes.

[0063] The advantages and positive effects of the present invention are:

[0064] In the present application, the liquid surface distance is controlled by monitoring the reflection area of ​​the guide tube, thereby avoiding the defect in the prior art that monitoring cannot be performed due to the small distance between the edge of the lower edge of the guide tube and its reflection, making the monitoring more accurate and the control of the liquid surface distance more stable.

[0065] The embodiments of the present invention are described in detail above, but the contents described are only preferred embodiments of the present invention and cannot be considered to limit the scope of implementation of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. A method for controlling the liquid level of a single crystal furnace, characterized in that: Includes steps: Before stabilizing the temperature, set the liquid level distance to the standard liquid level distance; During the crystal pulling process, an image of the reflection of the guide tube is obtained; Calculating the area of ​​the reflection of the guide tube according to the image; According to the change of the area of ​​the reflection of the guide tube, the liquid surface distance is controlled to approach the standard liquid surface distance.

2. A method for controlling a single crystal furnace liquid level according to claim 1, characterized in that: Before the temperature is stabilized in the step, the liquid level distance is set to the standard liquid level distance, including: Before stabilizing the temperature, lower the liquid level detection object to the height of the standard liquid level distance; The crucible is moved so that the liquid surface contacts the liquid level detection object.

3. A single crystal furnace liquid level control method according to claim 2, characterized in that: Before lowering the liquid level detection object, the liquid level detection object needs to be zero-calibrated.

4. A method for controlling a single crystal furnace liquid level according to claim 3, characterized in that: The liquid level detection object is clamped by a weight chuck, and the zero position of the liquid level detection object is that the weight chuck is flush with the lower edge of the guide tube.

5. A single crystal furnace liquid level control method according to any one of claims 1 to 4, characterized in that: The step calculates the area of ​​the reflection of the guide tube according to the image, and the reflection of the guide tube is an ellipse. According to the image, measuring the length a of the major semi-axis of the ellipse; Calculate the length b of the minor semi-axis of the ellipse; The area is calculated based on the length a of the major semi-axis and the length b of the minor semi-axis.

6. A method for controlling the liquid level of a single crystal furnace according to claim 5, characterized in that: The step calculates the length b of the minor semi-axis of the ellipse, Extract the coordinates (x, y) of the pick-up point on the ellipse; According to the standard equation of the ellipse, the length b of the minor semi-axis is calculated.

7. A single crystal furnace liquid level control method according to any one of claims 1 to 4 and 6, characterized in that: The step controls the liquid surface distance to approach the standard liquid surface distance according to the change of the area of ​​the reflection of the guide tube, adopts a self-correcting PID closed-loop control system, and controls the crucible to rise by comparing the area of ​​the reflection of the guide tube with the initial area, so that the area of ​​the reflection of the guide tube approaches the initial area.

8. A single crystal furnace liquid level control system, characterized in that: include: Liquid level distance measurement module, used to set the liquid level distance to the standard liquid level distance before temperature stabilization; An image acquisition module is used to acquire an image of the reflection of the guide tube during the crystal pulling process; A calculation processing module, used for calculating the area of ​​the reflection of the guide tube according to the image; A control module is used to control the liquid level distance to approach the standard liquid level distance according to the change of the area of ​​the reflection of the guide tube.

9. An electronic device, characterized in that: The electronic device comprises a memory, a processor and one or more programs stored in the memory and executable on the processor. When the one or more programs are executed by the processor, the electronic device executes the single crystal furnace liquid level control method as described in any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer instructions, and when the computer instructions are executed on a processor of an electronic device, the device where the computer storage medium is located executes the single crystal furnace liquid level control method as described in any one of claims 1-7.

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