Method for measuring absolute liquid level of silicon material in single crystal silicon rod Czochralski process

Abstract

The application discloses a kind of single crystal silicon rod Czochralski process silicon material absolute liquid distance measurement method.The measurement method is to the image about draft tube, silicon material liquid level and draft tube in the reflection of silicon material liquid level draft tube arc and silicon material liquid level arc Two-dimensional feature detection, according to the two-dimensional feature of the draft tube arc and the silicon material liquid level arc Three-dimensional coordinates of the draft tube arc and the silicon material liquid level arc are determined, the three-dimensional coordinates of the draft tube arc and the silicon material liquid level arc are fitted out draft tube lower along space circle and draft tube lower along reflection space circle using space circle fitting algorithm, the distance between the draft tube lower along space circle and the draft tube lower along reflection space circle is determined to the absolute liquid distance of the silicon material.The beneficial effects of the present application: compared with the monocular measurement method that pixel distance from draft tube to its reflection is generally used at present and the proportionality coefficient and offset required for conversion of pixel physical value are combined to determine the lifting pot, the present application directly gives the physical quantity of liquid distance change.

Description

Technical Field

[0001] This invention relates to the preparation of single-crystal silicon rods, and more particularly, to a method for measuring the absolute liquid gap of silicon material in the Czochralski process of single-crystal silicon rods. Background Technology

[0002] The Czochralski method for preparing single-crystal silicon rods is one of the most fundamental and crucial steps in the semiconductor and photovoltaic fields. The purity of the resulting single-crystal silicon rods directly determines the product quality of downstream industries (e.g., photovoltaic silicon wafers, semiconductor chips).

[0003] The Czochralski method for silicon ingot growth includes the following steps: Step S1, polycrystalline silicon is melted in a quartz crucible by heating. Step S2, a single-crystal silicon seed is inserted into the silicon and rotated and pulled to grow a single-crystal silicon rod. The growth process of the single-crystal silicon rod can be divided into several stages, including temperature stabilization, seeding, shoulder formation, shoulder rotation, and constant diameter. Each of these stages requires the silicon melt gap as negative feedback to guide the control system and control the growth of the single-crystal silicon rod.

[0004] Currently, the common practice in the industry for measuring the liquid distance of silicon is to set a liquid distance measurement frame at a specified height position in an image captured by an industrial camera. The pixel distance between the guide tube arc and the liquid surface arc, positioned by this liquid distance measurement frame, is measured and converted into the corresponding physical value using calibration coefficients. These calibration coefficients include a proportionality coefficient K and an offset B, which need to be obtained through experiments with a lifting pot. It should be noted that after each furnace start-up and closure, due to the difference in position between the guide tube and the furnace platform, the above liquid distance measurement frame and calibration coefficients are no longer applicable and need to be readjusted, making the crystal pulling process cumbersome. Summary of the Invention

[0005] The technical objective of this invention is to solve the problems in the prior art and provide a novel method for measuring the absolute liquid gap of silicon material in the Czochralski process of single crystal silicon rods.

[0006] To achieve the above-mentioned technical objectives, the technical solution of the present invention is as follows: A method for measuring the absolute liquid gap of silicon material in a single-crystal silicon rod Czochralski process, characterized in that it includes:

[0007] Step S1: Provide a single crystal furnace, a binocular camera structure, and an off-furnace calibration structure; the single crystal furnace includes: a furnace body, a crucible inside the furnace body, and a flow guide tube, wherein the crucible contains silicon material, the flow guide tube is directly above the surface of the silicon material, and the furnace body has a camera observation window obliquely above the flow guide tube; the binocular camera structure includes: a binocular camera mounted on a camera base, the camera base being detachable from the camera observation window; the off-furnace calibration structure includes: a calibration plate base mounted on a linear slide rail, and a calibration plate mounted on the calibration plate base, the camera base being detachable from the linear slide rail;

[0008] Step S2, the temperature stabilization stage of the single crystal silicon rod, the binocular camera sequentially performs shooting adjustment and furnace calibration operations;

[0009] The shooting adjustment operation includes: moving the binocular camera structure to the camera observation window, with the camera base fixed at a preset position in the camera observation window; adjusting the camera pose and focus of the binocular camera to ensure that the binocular camera can clearly capture images of the guide tube, the silicon liquid surface, and the reflection of the guide tube on the silicon liquid surface; and locking the relative pose of the binocular camera and the camera focus of the binocular camera after the adjustment is completed.

[0010] The off-furnace calibration operation includes: moving the binocular camera structure to the off-furnace calibration structure and calibrating the pose relationship of the binocular camera and the pose relationship between the binocular camera and the silicon liquid surface;

[0011] Step S3: After the furnace calibration operation, the binocular camera performs a measurement operation;

[0012] The measurement operation includes: moving the binocular camera structure to the camera observation window, and re-fixing the camera base to a preset position on the camera observation window; the binocular camera capturing images of the guide tube, the silicon liquid surface, and the reflection of the guide tube on the silicon liquid surface, wherein the images include at least: the guide tube arc and the silicon liquid surface arc at the two ends of the reflection;

[0013] Step S4: Perform two-dimensional feature detection on the images of the guide tube, the silicon liquid surface, and the reflection, identifying the arcs of the guide tube and the silicon liquid surface. Determine the three-dimensional coordinates of the guide tube arc and the silicon liquid surface arc based on their two-dimensional features. Use the three-dimensional coordinates of the guide tube arc and the silicon liquid surface arc to fit a spatial circle fitting algorithm to obtain the lower edge spatial circle of the guide tube and the lower edge reflection spatial circle of the guide tube. Determine the absolute liquid distance of the silicon material based on the distance between the lower edge spatial circle of the guide tube and the lower edge reflection spatial circle of the guide tube.

[0014] As a preferred embodiment of a method for measuring the absolute liquid gap of silicon material in a single-crystal silicon rod Czochralski process, the camera base is configured to allow for degree-of-freedom adjustment of the binocular camera, wherein the degree-of-freedom adjustment is any one or a combination of pitch adjustment, roll adjustment, yaw adjustment, X-axis adjustment, Y-axis adjustment, and Z-axis adjustment.

[0015] As a preferred embodiment of a method for measuring the absolute liquid gap of silicon material in a Czochralski process for monocrystalline silicon rods, the calibration plate base is configured to allow for degree-of-freedom adjustment of the calibration plate, wherein the degree-of-freedom adjustment is any one or a combination of pitch adjustment, roll adjustment, yaw adjustment, X-axis adjustment, Y-axis adjustment, and Z-axis adjustment.

[0016] As a preferred method for measuring the absolute liquid gap of silicon material in the Czochralski process of monocrystalline silicon rods, in the shooting adjustment operation, under the premise that the binocular camera can capture the complete guide tube, the distance between the two cameras in the binocular camera is increased as much as possible.

[0017] As a preferred embodiment of a method for measuring the absolute liquid gap of silicon material in a Czochralski process for monocrystalline silicon rods, during the off-furnace calibration operation, the relative pose of the binocular camera and the camera base, and the camera focus of the binocular camera are kept locked; the camera base is mounted on the linear slide rail, and the relative distance and angle between the camera base and the calibration plate base are adjusted until the binocular camera can clearly capture the calibration image of the calibration plate; the calibration plate image of the calibration plate is captured by the binocular camera to calibrate the pose relationship of the binocular camera and the pose relationship between the binocular camera and the liquid silicon surface.

[0018] As a preferred method for measuring the absolute liquid distance of silicon material in the Czochralski process of monocrystalline silicon rods, in step S4, the coordinate point set of the guide tube arc and the silicon material liquid surface arc at the two ends of the reflection is located by contour positioning, spot positioning or edge positioning method. The guide tube arc point pair and the silicon material liquid surface arc point pair paired by the binocular camera are obtained by feature matching method, and the three-dimensional spatial coordinates corresponding to these point pairs are calculated using calibration information.

[0019] As a preferred method for measuring the absolute liquid gap of silicon material in the Czochralski process of single crystal silicon rods, the coordinate point set is the point set of the original data, the point set after smoothing the original data, or the point set obtained by discrete sampling of part of the arc after performing circle fitting or ellipse fitting on the original data.

[0020] As a preferred method for measuring the absolute liquid gap of silicon material in the Czochralski process of single-crystal silicon rods, the feature matching method is a SURF, SIFT, ORB detection operator, or a feature extraction algorithm based on a deep learning neural network.

[0021] A preferred embodiment of a method for measuring the absolute liquid gap of silicon material in a Czochralski process for single-crystal silicon rods further includes:

[0022] Step S5: Determine the true diameter of the guide tube based on the diameter of the lower edge space circle of the guide tube or the diameter of the reflection space circle of the lower edge of the guide tube.

[0023] Compared with existing technologies, the beneficial effects of this invention are at least as follows: The measurement method provides absolute liquid distance data during the temperature stabilization, crystal pulling, shoulder formation, shoulder rotation, and constant diameter stages of single-crystal silicon growth. Compared with the currently widely used monocular measurement method that calculates the pixel distance from the guide tube to its reflection and combines it with lifting the pot to determine the scaling factor and offset required for pixel physical value conversion, this invention directly provides the physical quantity of liquid distance change. It eliminates the need for readjustment of the detection position and calibration of the liquid distance coefficient after furnace opening and closing, simplifying the crystal pulling process. The detection results accurately reflect the distance from the guide tube to the silicon molten surface. Furthermore, it can measure the true diameter of the guide tube, providing a reference benchmark for other visual inspection items such as diameter detection.

[0024] In addition to the problems described above, the technical features constituting the technical solutions, and the beneficial effects brought about by these technical features, other technical problems that the present invention can solve, other technical features contained in the technical solutions, and the beneficial effects brought about by these technical features will be further explained in detail with reference to the accompanying drawings. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the single crystal furnace in this invention.

[0026] Figure 2 This is a schematic diagram of the structure of the binocular camera component in this invention.

[0027] Figure 3 This is a schematic diagram of the off-furnace calibration structure in this invention.

[0028] Figure 4 This is a flowchart of the method of the present invention.

[0029] Figure 5 This is a schematic diagram of the image of the guide tube, the silicon liquid surface, and the reflection formed by the guide tube on the silicon liquid surface in this invention.

[0030] Figure 6 This is a schematic diagram of the lower edge spatial circle of the guide tube and the reflected spatial circle of the lower edge of the guide tube in this invention. Implementation

[0031] The present invention will now be described in further detail with reference to specific embodiments and accompanying drawings. It should be noted that these descriptions of embodiments are intended to aid in understanding the invention and do not constitute a limitation thereof. Furthermore, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0032] Please see Figure 1The figure shows a single crystal furnace 1. The single crystal furnace 1 includes: a furnace body 11, a crucible 12 inside the furnace body 11, and a flow guide tube 13. The crucible 12 contains silicon material 14. The flow guide tube 13 is directly above the silicon material liquid surface 140. The furnace body 11 has a camera observation window 15 diagonally above the flow guide tube 13.

[0033] Please see Figure 2 The figure shows a binocular camera structure 2. The binocular camera structure 2 includes a binocular camera 22 mounted on a camera base 21. The binocular camera 22 consists of a first camera 221 and a second camera 222 arranged side-by-side with the first camera 221. The camera base 21 is detachable from the camera observation window 15. When the camera base 21 is fixed at a preset position in the camera observation window 15, the binocular camera 22 is used to capture images of the guide tube 13, the silicon liquid surface 140, and the reflection of the guide tube 13 on the silicon liquid surface 140.

[0034] Preferably, the camera base 21 is configured to allow for degree-of-freedom adjustment of the binocular camera 22. The degree-of-freedom adjustment includes any one or a combination of pitch, roll, yaw, X-axis, Y-axis, and Z-axis adjustments.

[0035] Please see Figure 3 The figure shows an off-furnace calibration structure 3. The off-furnace calibration structure 3 includes: a calibration plate base 32 mounted on a linear slide rail 31, and a calibration plate 33 mounted on the calibration plate base 32. The camera base 21 of the binocular camera structure 2 is detachably mounted to the linear slide rail 31. During off-furnace calibration, the camera base 21 is mounted on the linear slide rail 31, and the binocular camera 22 is positioned relative to the calibration plate 33. The linear slide rail 31 can be used to adjust the distance between the binocular camera 22 and the calibration plate 33.

[0036] Preferably, the calibration plate base 32 is configured to allow for degree-of-freedom adjustment of the calibration plate 33. The degree-of-freedom adjustment includes any one or a combination of pitch adjustment, roll adjustment, yaw adjustment, X-axis adjustment, Y-axis adjustment, and Z-axis adjustment.

[0037] Please see Figure 4 The figure illustrates a method for measuring the absolute liquid gap of silicon material in a Czochralski process for single-crystal silicon rods. The method for measuring the absolute liquid gap of silicon material includes:

[0038] Step S1: Provide the single crystal furnace 1, the binocular camera structure 2, and the furnace calibration structure 3.

[0039] In step S2, during the temperature stabilization stage of the single crystal silicon rod, the binocular camera 22 sequentially performs shooting adjustment operations and furnace calibration operations.

[0040] The shooting adjustment process includes: moving the binocular camera structure 2 to the camera observation window 15. The camera base 21 is fixed at a preset position in the camera observation window 15. The camera pose and focus of the binocular camera 22 are adjusted (focusing on the silicon liquid surface 140) to ensure that the binocular camera 22 can clearly capture images of the guide tube 13, the silicon liquid surface 140, and the reflection of the guide tube 13 on the silicon liquid surface 140. The binocular camera 22 should be able to capture the entire guide tube 13. After adjustment, the relative pose between the binocular camera 22 and the camera base 21, and the camera focus of the binocular camera 22 are locked.

[0041] Preferably, provided that the binocular camera 22 can capture the entire flow guide tube 13, the distance between the first camera 221 and the second camera 222 in the binocular camera 22 should be increased as much as possible in order to increase the measurement accuracy.

[0042] The off-furnace calibration operation includes: moving the binocular camera structure 2 to the off-furnace calibration structure 3 and calibrating the pose relationship between the binocular camera 22 (the first camera 221 and the second camera 222) and the pose relationship between the binocular camera 22 and the silicon liquid surface 140. The pose relationship includes: position, orientation, etc.

[0043] Specifically, the relative pose of the binocular camera 22 and the camera base 21 and the camera focus of the binocular camera 22 are kept locked; the camera base 21 is mounted on the linear slide rail 31, and the relative distance and angle between the camera base 21 and the calibration plate base 32 are adjusted until the binocular camera 22 can clearly capture the calibration image of the calibration plate 33. At this time, the relative pose of the binocular camera 22 and the calibration plate 33 and the relative pose of the binocular camera 22 and the silicon liquid surface 140 are the same or similar; the calibration plate image of the calibration plate 33 is captured by the binocular camera 22 to calibrate the pose relationship of the binocular camera 22 (the first camera and the second camera) and the pose relationship between the binocular camera 22 and the silicon liquid surface 140.

[0044] Preferably, the degrees of freedom of the calibration plate 33 are finely adjusted to capture more images of the calibration plate, making the calibration results more reliable.

[0045] Step S3, after the furnace calibration operation (including: temperature stabilization stage, crystal pulling stage, shoulder formation stage, shoulder turning stage, and equal diameter stage of the single crystal silicon rod), the binocular camera 22 performs a measurement operation to obtain images of the guide tube 13, the silicon liquid surface 140, and the reflection of the guide tube 13 on the silicon liquid surface 140.

[0046] The measurement operation includes: moving the binocular camera structure 2 to the camera observation window 15. The camera base 21 is then repositioned to a preset position on the camera observation window 15. The binocular camera 22 captures an image of the guide tube 13, the silicon liquid surface 140, and the reflection of the guide tube 13 on the silicon liquid surface 140. The image includes at least: the guide tube arc 41 and the silicon liquid surface arc 42 at the two ends of the reflection.

[0047] Please see Figure 5 The image shows an image of the guide tube 13, the silicon slurry surface 140, and the reflection. The image includes: the guide tube arc 41 and the silicon slurry surface arc 42. The portion between the guide tube arc 41 and the silicon slurry surface arc 42 is the reflection of the guide tube 13 on the silicon slurry surface 140. Because the camera viewing window 15 is diagonally above the guide tube 13, i.e., the binocular camera 22 is shooting diagonally downwards, the distance between the guide tube arc 41 and the silicon slurry surface arc 42 shows a trend of being larger at the top and smaller at the bottom.

[0048] Step S4: Perform two-dimensional feature detection on the images of the guide tube 13, the silicon liquid surface 140, and the reflection, identifying the two-dimensional features of the guide tube arc 41 and the silicon liquid surface arc 42. Determine the three-dimensional coordinates of the guide tube arc 41 and the silicon liquid surface arc 42 based on their two-dimensional features. Then, fit the three-dimensional coordinates of the guide tube arc 41 and the silicon liquid surface arc 42 using a spatial circle fitting algorithm to obtain the lower edge spatial circle 43 of the guide tube and the lower edge reflection spatial circle 44 of the guide tube (see...). Figure 6 The distance between the lower edge space circle 43 of the guide tube and the reflection space circle 44 of the lower edge of the guide tube is calculated to obtain the absolute liquid distance of the silicon material.

[0049] Since the silicon liquid surface 140 is mirror-like at high temperature, the lower edge space circle 43 of the guide tube and the lower edge reflection space circle 44 of the guide tube are symmetrical about the silicon liquid surface 140. As long as the distance between the lower edge space circle 43 of the guide tube and the lower edge reflection space circle 44 of the guide tube is calculated, half of its value is the silicon liquid distance.

[0050] Specifically, the coordinate point set of the guide tube arc 41 and the silicon liquid surface arc 42 at the two ends of the reflection is located by contour positioning, spot positioning, edge positioning, or other existing positioning methods. The coordinate point set can be the point set of the original data, the point set after smoothing the original data, the point set obtained by discretizing part of the arc after performing circle fitting or ellipse fitting on the original data, or any other point set obtained after data processing for filtering or approximation.

[0051] Specifically, the pair of points 41 on the guide tube and the pair of points 42 on the silicon liquid surface paired with the binocular camera 22 are obtained through a feature matching method, and the three-dimensional spatial coordinates corresponding to these point pairs are calculated using calibration information. The feature matching method can be either a traditional detection operator such as SURF, SIFT, or ORB, or a feature extraction algorithm based on a deep learning neural network.

[0052] The distance between the lower edge spatial circle 43 of the guide tube and the reflected spatial circle 44 of the lower edge of the guide tube is one of the following: shortest distance Hmin, longest distance Hmax, average distance Havg, and specified distance Hset, or any combination thereof. The shortest distance Hmin is preferred. This is because existing methods for measuring the absolute liquid distance of silicon only calculate the distance between the guide tube arc 41 and the silicon liquid surface arc 42 at one end of the reflected image. A drawback is that if the lower edge of the guide tube is severely tilted relative to the silicon liquid surface 140, the measured value may be within a safe range, but the silicon liquid surface 140 may have already touched the guide tube 13. The shortest distance method overcomes this drawback.

[0053] Step S5: Calculate the diameter of the lower edge space circle 43 of the guide tube or the reflection space circle 44 of the lower edge of the guide tube. The diameter is the true diameter of the guide tube 13 and can be used as a reference for other visual inspection items.

[0054] The above description merely illustrates embodiments of the present invention and is quite specific and detailed; however, it should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the inventive concept, and these all fall within the scope of protection of the present invention. Therefore, the scope of protection of this invention should be determined by the appended claims.

Claims

1. A method for measuring the absolute liquid gap of silicon material in a Czochralski process for single-crystal silicon rods, characterized in that, include: Step S1: Provide a single crystal furnace, a binocular camera structure, and an off-furnace calibration structure; the single crystal furnace includes: a furnace body, a crucible inside the furnace body, and a flow guide tube, wherein the crucible contains silicon material, the flow guide tube is directly above the surface of the silicon material, and the furnace body has a camera observation window obliquely above the flow guide tube; the binocular camera structure includes: a binocular camera mounted on a camera base, the camera base being detachable from the camera observation window; the off-furnace calibration structure includes: a calibration plate base mounted on a linear slide rail, and a calibration plate mounted on the calibration plate base, the camera base being detachable from the linear slide rail; Step S2, the temperature stabilization stage of the single crystal silicon rod, the binocular camera sequentially performs shooting adjustment and furnace calibration operations; The shooting adjustment operation includes: moving the binocular camera structure to the camera observation window, with the camera base fixed at a preset position in the camera observation window; adjusting the camera pose and focus of the binocular camera to ensure that the binocular camera can clearly capture images of the guide tube, the silicon liquid surface, and the reflection of the guide tube on the silicon liquid surface; and locking the relative pose of the binocular camera and the camera focus of the binocular camera after the adjustment is completed. The off-furnace calibration operation includes: moving the binocular camera structure to the off-furnace calibration structure and calibrating the pose relationship of the binocular camera and the pose relationship between the binocular camera and the silicon liquid surface; Step S3: After the furnace calibration operation, the binocular camera performs a measurement operation; The measurement operation includes: moving the binocular camera structure to the camera observation window, and re-fixing the camera base to a preset position on the camera observation window; the binocular camera capturing images of the guide tube, the silicon liquid surface, and the reflection of the guide tube on the silicon liquid surface, wherein the images include at least: the guide tube arc and the silicon liquid surface arc at the two ends of the reflection; Step S4: Perform two-dimensional feature detection on the images of the guide tube, the silicon liquid surface, and the reflection, identifying the arcs of the guide tube and the silicon liquid surface. Determine the three-dimensional coordinates of the guide tube arc and the silicon liquid surface arc based on their two-dimensional features. Use the three-dimensional coordinates of the guide tube arc and the silicon liquid surface arc to fit a spatial circle fitting algorithm to obtain the lower edge spatial circle of the guide tube and the lower edge reflection spatial circle of the guide tube. Determine the absolute liquid distance of the silicon material based on the distance between the lower edge spatial circle of the guide tube and the lower edge reflection spatial circle of the guide tube.

2. The method for measuring the absolute liquid gap of silicon material in the Czochralski process of single-crystal silicon rods according to claim 1, characterized in that, The camera base is configured to allow for degree-of-freedom adjustment of the binocular camera, wherein the degree-of-freedom adjustment is any one or a combination of pitch adjustment, roll adjustment, yaw adjustment, X-axis adjustment, Y-axis adjustment, and Z-axis adjustment.

3. The method for measuring the absolute liquid gap of silicon material in the Czochralski process of single-crystal silicon rods according to claim 1, characterized in that, The calibration plate base is configured to allow for degree-of-freedom adjustment of the calibration plate, wherein the degree-of-freedom adjustment is any one or a combination of pitch adjustment, roll adjustment, yaw adjustment, X-axis adjustment, Y-axis adjustment, and Z-axis adjustment.

4. The method for measuring the absolute liquid gap of silicon material in the Czochralski process of single-crystal silicon rods according to claim 1, characterized in that, During the shooting adjustment operation, under the premise that the binocular camera can capture the entire guide tube, the distance between the two cameras in the binocular camera should be increased as much as possible.

5. The method for measuring the absolute liquid gap of silicon material in the Czochralski process of single-crystal silicon rods according to claim 1, characterized in that, During the off-furnace calibration operation, the relative pose of the binocular camera and the camera base is kept locked, and the binocular camera is focused. The camera base is mounted on the linear slide rail, and the relative distance and angle between the camera base and the calibration plate base are adjusted until the binocular camera can clearly capture the calibration image of the calibration plate. The calibration plate image of the calibration plate is captured by the binocular camera to calibrate the pose relationship of the binocular camera and the pose relationship between the binocular camera and the silicon liquid surface.

6. The method for measuring the absolute liquid gap of silicon material in the Czochralski process of single-crystal silicon rods according to claim 1, characterized in that, In step S4, the coordinate point set of the guide tube arc and the silicon liquid surface arc at the two ends of the reflection is located by contour positioning, spot positioning or edge positioning method. The guide tube arc point pair and the silicon liquid surface arc point pair paired by the binocular camera are obtained by feature matching method, and the three-dimensional spatial coordinates corresponding to these point pairs are calculated by using calibration information.

7. The method for measuring the absolute liquid gap of silicon material in the Czochralski process of single-crystal silicon rods according to claim 6, characterized in that, The coordinate point set is the point set of the original data, the point set after smoothing the original data, or the point set obtained by discretely sampling a portion of the arc after fitting the original data to a circle or ellipse.

8. The method for measuring the absolute liquid gap of silicon material in the Czochralski process of single-crystal silicon rods according to claim 6, characterized in that, The feature matching method is the SURF, SIFT, ORB detection operator, or a feature extraction algorithm based on a deep learning neural network.

9. The method for measuring the absolute liquid gap of silicon material in the Czochralski process of single-crystal silicon rods according to claim 1, characterized in that, Further includes: Step S5: Determine the true diameter of the guide tube based on the diameter of the lower edge space circle of the guide tube or the diameter of the reflection space circle of the lower edge of the guide tube.

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