A high-precision liquid level movement position measurement component and measurement method

Abstract

The present invention discloses a high-precision liquid level movement position measurement component and measurement method, comprising: a crucible, wherein the crucible is filled with silicon liquid; a guide tube, wherein the guide tube is arranged above the silicon liquid, and a high-temperature resistant component is provided at the bottom of the guide tube; a crystal rod cooling device, wherein the crystal rod cooling device is arranged above the silicon liquid and the crystal rod cooling device is arranged in the guide tube, and a plurality of crystal pulling holes are provided at the bottom of the crystal rod cooling device; a camera, which is used to obtain images of the high-temperature resistant component and its reflection on the silicon liquid surface; a controller, which is used to receive and process data transmitted by the camera; a protrusion is provided on the high-temperature resistant component, and a through hole is provided on the protrusion. The high-precision liquid level movement position measurement component and measurement method of the present invention are easy to use. Through camera measurement and controller control, the movement position of the bottom of the crystal rod cooling device and the raw silicon liquid surface can be measured and controlled in real time, thereby controlling the diameter of the crystal rod.

Description

Technical Field

[0001] The present invention relates to the technical field of silicon core production, and in particular to a high-precision liquid level movement position measurement component and a measurement method. Background Art

[0002] Multi-crystal and single-crystal silicon are important raw materials for industries such as semiconductors and photovoltaics. During their production, silicon cores are used in significant quantities. Currently, the most advanced silicon core production method utilizes a multi-turn Czochralski crystal growth furnace to directly pull multiple silicon cores. This method heats and melts the raw material into a liquid state, then uses seed crystals to seed the liquid material, causing it to recrystallize into the desired silicon cores. To maintain stable crystal growth and control the diameter of the ingot, the liquid level must be moved at an appropriate speed and with appropriate positional accuracy during the production process, ensuring a consistent and stable distance between the bottom of the silicon core cooling device and the silicon liquid level. Therefore, measuring the liquid level's movement is crucial for stable silicon core growth.

[0003] Currently, vision systems generally use horizontal measurement to measure liquid surface movement. This method cannot linearly represent changes in liquid surface movement. This existing technology suffers from poor accuracy, large fluctuations, and inability to precisely control the liquid surface position. Some methods use a specific angle for oblique measurement, but this angle is affected by the mounting angle of the measurement camera, requiring the initial production of a crystal ingot to obtain this specific angle value. Without physical calibration of the actual liquid surface position, actual liquid surface movement changes are manually determined based on experience, which is significantly influenced by subjective factors.

[0004] Based on the above situation, the present invention proposes a high-precision liquid level movement position measurement component and measurement method, which can effectively solve the above problems. Summary of the Invention

[0005] The present invention aims to provide a high-precision liquid level movement position measurement assembly and measurement method. The high-precision liquid level movement position measurement assembly and measurement method of the present invention are convenient to use. Through camera measurement and controller control, they achieve real-time measurement and control of the movement position between the bottom of the crystal ingot cooling device and the level of the raw silicon liquid, thereby controlling the diameter of the crystal ingot.

[0006] The present invention is achieved through the following technical solutions:

[0007] A high-precision liquid level movement position measurement component, comprising:

[0008] a crucible containing silicon liquid;

[0009] A guide tube, which is arranged above the silicon liquid and has a high-temperature resistant component at the bottom;

[0010] A crystal ingot cooling device is provided above the silicon liquid and inside the guide tube, and a plurality of crystal pulling holes are provided at the bottom of the crystal ingot cooling device;

[0011] a camera for acquiring images of the high-temperature resistant component and its reflection on the silicon liquid surface;

[0012] The controller is used to receive and process the data transmitted by the camera;

[0013] The high temperature resistant component is provided with a protrusion, and the protrusion is provided with a through hole.

[0014] The present invention aims to provide a high-precision liquid level movement position measurement assembly and measurement method. The high-precision liquid level movement position measurement assembly and measurement method of the present invention are convenient to use. Through camera measurement and controller control, they achieve real-time measurement and control of the movement position between the bottom of the crystal ingot cooling device and the level of the raw silicon liquid, thereby controlling the diameter of the crystal ingot.

[0015] Preferably, a static capacitance detection device is provided at the bottom of the crystal rod cooling device.

[0016] Preferably, the electrostatic capacitance detection device includes a silicon liquid contact piece and a signal amplifier that are electrically connected in sequence, the silicon liquid contact piece protrudes downward from the bottom of the electrostatic capacitance detection device by a distance L1, and the signal amplifier is electrically connected to the controller.

[0017] Preferably, the signal amplifier includes a resistor R1 and a sliding rheostat R2, one end of the resistor R1 and one end of the sliding rheostat R2 are electrically connected through a first wire, a second wire is connected to the first wire, the other end of the resistor R1 is connected to a third wire, and the other end of the sliding rheostat R2 is connected to a fourth wire.

[0018] Preferably, a mounting hole is provided on the high temperature resistant component.

[0019] A method for measuring a high-precision liquid level movement position measuring assembly comprises the following steps:

[0020] Step S1: Preset a reference measurement value D0 in the controller. When the liquid level position is first confirmed, slowly raise the crucible. When the controller detects the output voltage of the electrostatic capacitance detection device, it immediately stops raising the crucible.

[0021] Step S2: The crucible is lowered by a distance D1. At this time, the physical distance between the bottom of the crystal ingot cooling device and the liquid surface is D2. The calculation formula is:

[0022] D2=(L1+D1)

[0023] Wherein, L1 is the protruding length of the electrostatic capacitance detection device;

[0024] Step S3: After the liquid surface stabilizes, the camera captures an image of the high-temperature resistant component and its reflection in the liquid surface;

[0025] Step S4: The pixel distance between the through hole of the high-temperature resistant component in the image and the through hole of the high-temperature resistant component in the reflection is D3. At this time, the actual physical distance D2 and the camera measured pixel distance D3 are calibrated to be the relationship between the current actual liquid surface distance and the industrial camera measured distance;

[0026] Step S5: The crucible slowly descends 5 mm, and the camera captures an image of the high-temperature resistant component and its reflection in the liquid surface.

[0027] Step S6: The pixel distance between the through hole of the high-temperature resistant component in the image and the through hole of the high-temperature resistant component in the reflection is D4. The pixel measurement value D5 corresponding to each decrease of 0.01 mm is calculated using the following formula:

[0028] D5=(D4-D3) / 500;

[0029] Step S7: inputting D5 into the controller, and calibrating D5 in the controller as the pixel change corresponding to each 0.01 mm drop of the actual crucible;

[0030] Step S8: When the ingot is in the continuous growth process, the camera observes that the through-hole of the high-temperature resistant component and its reflection will change with the actual movement of the liquid level. The camera records the pixel distance D6 between the through-hole of the high-temperature resistant component and the through-hole of the high-temperature resistant component in the reflection in real time, and calculates the actual liquid level distance D7 using the formula D7 = D2 + (D6 - D3) / D5 * 0.01 to obtain real-time information on the movement of the liquid level.

[0031] Step S9: Feedback the liquid level distance D7 to the controller, which compares the real-time liquid level distance D7 with the reference measurement value D0, and then performs the crucible lifting and lowering action according to the comparison result to adjust the liquid level position height.

[0032] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0033] 1. An electrostatic capacitance detection device is used to determine the actual physical distance between the liquid surface and the bottom of the crystal rod cooling device, thereby avoiding the error caused by manual visual observation.

[0034] 2. The high-temperature resistant components are equipped with through holes, which facilitates the extraction of target features during visual measurement and achieves higher measurement accuracy. This avoids the problems of poor reflection, difficulty in feature extraction, and the generation of oxides in traditional graphite materials.

[0035] 3. Through two calibrations, the relationship between the actual physical distance and the pixel measurement value, as well as the relationship between the pixel distance corresponding to the crucible rising and falling by 0.01 mm, are calibrated respectively. The change in the measured value is consistent with the change in the actual distance value, and the overall error is within 1%, which meets the requirements of silicon rod drawing.

[0036] 4. Compare the calculated actual distance between the through hole of the high-temperature resistant component and its reflection with the set target value, and then feed back the comparison result to the controller. The controller controls the lifting and lowering of the crucible to adjust the liquid level position, realizing real-time measurement and control of the moving position of the bottom of the crystal rod cooling device and the liquid level of the raw silicon liquid, thereby controlling the diameter of the crystal rod. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a structural schematic diagram of the present invention;

[0038] Figure 2 for Figure 1 Schematic diagram of the local enlarged structure at A in the middle;

[0039] Figure 3 This is a schematic structural diagram of the signal amplifier of the present invention;

[0040] Figure 4 This is a schematic structural diagram of the high-temperature resistant component of the present invention. DETAILED DESCRIPTION

[0041] To help those skilled in the art better understand the technical solutions of the present invention, the preferred embodiments of the present invention are described below in conjunction with specific examples. However, it should be understood that the drawings are for illustrative purposes only and are not to be construed as limiting this patent. To better illustrate this embodiment, some components in the drawings may be omitted, enlarged, or reduced, and do not represent the dimensions of actual products. For those skilled in the art, it is understandable that some well-known structures and their descriptions may be omitted in the drawings. The positional relationships described in the drawings are for illustrative purposes only and are not to be construed as limiting this patent.

[0042] Unless otherwise specified, the controller and other technical features described in the present invention (constituent units / elements of the present invention) are obtained from conventional commercial channels or manufactured by conventional methods. Their specific structure, working principle, and possible control methods and spatial layout methods can be selected conventionally in the field and should not be regarded as the innovative points of the present invention. For those skilled in the art, this is understandable and the patent of this invention will not be further elaborated.

[0043] Example 1:

[0044] like Figures 1 to 4 As shown, a high-precision liquid level movement position measurement component includes:

[0045] Crucible 1, wherein the crucible 1 contains silicon liquid 2;

[0046] A guide tube 3 is provided above the silicon liquid 2 and a high temperature resistant component 6 is provided at the bottom of the guide tube 3;

[0047] A crystal ingot cooling device 4 is provided above the silicon liquid 2 and inside the guide tube 3. A plurality of crystal pulling holes 41 are provided at the bottom of the crystal ingot cooling device 4.

[0048] A camera 5 is used to obtain an image of the high-temperature resistant component 6 and its reflection on the silicon liquid surface;

[0049] The controller is used to receive and process the data transmitted by the camera 5;

[0050] The high temperature resistant component 6 is provided with a protrusion 61 , and the protrusion 61 is provided with a through hole 62 .

[0051] The ingot cooling device 4 is used to cool the ingot, which is placed in the pulling hole 41. The crucible 1 is usually equipped with a lifting device at the bottom, and the controller controls the lifting of the crucible 1, which belongs to the existing technology and will not be described in detail.

[0052] Example 2:

[0053] like Figures 1 to 4 As shown, a high-precision liquid level movement position measurement component includes:

[0054] Crucible 1, wherein the crucible 1 contains silicon liquid 2;

[0055] A guide tube 3 is provided above the silicon liquid 2 and a high temperature resistant component 6 is provided at the bottom of the guide tube 3;

[0056] A crystal ingot cooling device 4 is provided above the silicon liquid 2 and inside the guide tube 3. A plurality of crystal pulling holes 41 are provided at the bottom of the crystal ingot cooling device 4.

[0057] A camera 5 is used to obtain an image of the high-temperature resistant component 6 and its reflection on the silicon liquid surface;

[0058] The controller is used to receive and process the data transmitted by the camera 5;

[0059] The high temperature resistant component 6 is provided with a protrusion 61 , and the protrusion 61 is provided with a through hole 62 .

[0060] A static capacitance detection device is provided at the bottom of the crystal rod cooling device 4 .

[0061] Furthermore, in another embodiment, the electrostatic capacitance detection device includes a silicon liquid contact 7 and a signal amplifier electrically connected in sequence, the silicon liquid contact 7 protrudes downward from the bottom of the electrostatic capacitance detection device by a distance L1, and the signal amplifier is electrically connected to the controller.

[0062] Since the silicon liquid contact member 7 protrudes downward by a distance of L1, when the device contacts the silicon liquid surface, the electrostatic capacitance detection device is open-circuited and conductive, forming a closed circuit.

[0063] Furthermore, in another embodiment, the signal amplifier includes a resistor R1 and a sliding rheostat R2, one end of the resistor R1 and one end of the sliding rheostat R2 are electrically connected through a first wire 81, a second wire 82 is connected to the first wire 81, the other end of the resistor R1 is connected to a third wire 83, and the other end of the sliding rheostat R2 is connected to a fourth wire 84.

[0064] The PH terminal is connected to the PLC analog input port. The detection principle is that a voltage is applied across the silicon liquid contact 7. Since the silicon liquid contact 7 is not in contact with the silicon liquid surface, the detection device is in an open circuit state. The current direction is: 24V → 20K → A10P → 5.26K → A10N → 24N. The PH terminal of the detection device has no voltage output. When the silicon liquid contact 7 contacts the silicon liquid surface, the PH terminal of the detection device closes the circuit and outputs a voltage. The current direction is: 24V → 20K → A10P → PH. The voltage is amplified by the signal amplifier and output to the PLC analog input port. The PLC determines whether the silicon liquid contact 7 is in contact with the liquid surface based on the input voltage.

[0065] Furthermore, in another embodiment, a mounting hole 63 is provided on the high temperature resistant component 6 .

[0066] The installation hole 63 is provided to facilitate installation of the high temperature resistant component 6 on the guide hole.

[0067] According to another aspect of the present invention, a method for measuring a high-precision liquid level movement position measuring assembly is provided, comprising the following steps:

[0068] Step S1: A reference measurement value D0 is preset in the controller. When the liquid level position is first confirmed, the crucible 1 is slowly raised. When the controller detects the output voltage of the electrostatic capacitance detection device, that is, when the electrostatic capacitance detection device is in contact with the liquid surface, the raising of the crucible 1 is immediately stopped.

[0069] Step S2: The crucible 1 is lowered by a distance D1 (to prevent the high-temperature silicon liquid 2 from contacting the electrostatic capacitance detection device for a long time, thereby reducing the service life of the device). At this time, the physical distance between the bottom of the crystal ingot cooling device 4 and the liquid surface is D2, and the calculation formula is:

[0070] D2=(L1+D1)

[0071] Wherein, L1 is the protruding length of the electrostatic capacitance detection device;

[0072] Step S3: After the liquid surface stabilizes, the camera 5 captures an image of the high-temperature resistant component 6 and its reflection in the liquid surface;

[0073] Step S4: The pixel distance between the through hole 62 of the high-temperature resistant component 6 in the image and the through hole 62 of the high-temperature resistant component 6 in the reflection is D3. At this time, the actual physical distance D2 and the pixel distance D3 measured by the camera 5 are calibrated to be the relationship between the current actual liquid level distance and the distance measured by the industrial camera 5;

[0074] Step S5: The crucible 1 slowly descends 5 mm, and the camera 5 captures an image of the high-temperature resistant component 6 and its reflection in the liquid surface.

[0075] Step S6: The pixel distance between the through hole 62 of the high-temperature resistant component 6 in the image and the through hole 62 of the high-temperature resistant component 6 in the reflection is D4. The pixel measurement value D5 corresponding to each decrease of 0.01 mm is calculated using the following formula:

[0076] D5=(D4-D3) / 500;

[0077] Step S7: inputting D5 into the controller, and calibrating D5 in the controller as the pixel change corresponding to each 0.01 mm drop of the actual crucible 1;

[0078] Step S8: When the ingot is in the continuous growth process, the camera 5 observes that the through hole 62 of the high-temperature resistant component 6 and its reflection change with the actual movement of the liquid level. The camera 5 records the pixel distance D6 between the through hole 62 of the high-temperature resistant component 6 and the through hole 62 of the high-temperature resistant component 6 in the reflection in real time, and calculates the actual liquid level distance D7 using the formula D7 = D2 + (D6 - D3) / D5 * 0.01, thereby obtaining real-time information on the movement of the liquid level.

[0079] Step S9: Feedback the liquid level distance D7 to the controller, which will compare the real-time liquid level distance D7 with the reference measurement value D0. The controller then raises and lowers the crucible 1 according to the comparison result, and adjusts the liquid level position height so that the crystal growth rate matches the liquid level movement position speed. The liquid level movement position is kept in comparison and adjustment throughout the entire crystal pulling process to ensure that the size fluctuation of the crystal rod diameter is qualified.

[0080] According to the description and drawings of the present invention, those skilled in the art can easily manufacture or use the high-precision liquid level movement position measurement component and measurement method of the present invention, and can produce the positive effects described in the present invention.

[0081] Unless otherwise specified, in the present invention, if there are terms such as "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicating orientation or positional relationships, they are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the terms describing the orientation or positional relationships in the present invention are only used for illustrative purposes and cannot be understood as limiting this patent. For ordinary technicians in this field, they can understand the specific meanings of the above terms in conjunction with the drawings and according to specific circumstances.

[0082] Unless otherwise specified or limited, the terms "disposed," "connected," and "connected" in this disclosure should be interpreted broadly. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to direct connections, indirect connections through an intermediary, or internal connections between two components. Those skilled in the art will understand the specific meanings of these terms in this disclosure based on the specific circumstances.

[0083] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification or equivalent change made to the above embodiment based on the technical essence of the present invention shall fall within the scope of protection of the present invention.

Claims

1. A high-precision liquid level movement position measurement component, characterized in that: include: a crucible containing silicon liquid; A guide tube, which is arranged above the silicon liquid and has a high-temperature resistant component at the bottom; A crystal ingot cooling device is provided above the silicon liquid and inside the guide tube, and a plurality of crystal pulling holes are provided at the bottom of the crystal ingot cooling device; a camera for acquiring images of the high-temperature resistant component and its reflection on the silicon liquid surface; The controller is used to receive and process the data transmitted by the camera; The high temperature resistant component is provided with a protrusion, and the protrusion is provided with a through hole; A static capacitance detection device is provided at the bottom of the crystal rod cooling device; The electrostatic capacitance detection device includes a silicon liquid contact and a signal amplifier electrically connected in sequence, the silicon liquid contact protruding downward from the bottom of the electrostatic capacitance detection device by a distance L1, and the signal amplifier is electrically connected to the controller; The signal amplifier includes a resistor R1 and a sliding rheostat R2. One end of the resistor R1 and one end of the sliding rheostat R2 are electrically connected through a first wire. A second wire is connected to the first wire. The other end of the resistor R1 is connected to a third wire. The other end of the sliding rheostat R2 is connected to a fourth wire.

2. The high-precision liquid level movement position measurement assembly according to claim 1, characterized in that: The high temperature resistant component is provided with a mounting hole.

3. A method for measuring a high-precision liquid level movement position measuring assembly according to any one of claims 1 to 2, characterized in that: The following steps are involved: Step S1: Preset a reference measurement value D0 in the controller. When the liquid level position is first confirmed, slowly raise the crucible. When the controller detects the output voltage of the electrostatic capacitance detection device, it immediately stops raising the crucible. Step S2: The crucible is lowered by a distance D1. At this time, the physical distance between the bottom of the crystal ingot cooling device and the liquid surface is D2. The calculation formula is: D2=(L1+D1) Wherein, L1 is the protruding length of the electrostatic capacitance detection device; Step S3: After the liquid surface stabilizes, the camera captures an image of the high-temperature resistant component and its reflection in the liquid surface; Step S4: The pixel distance between the through hole of the high-temperature resistant component in the image and the through hole of the high-temperature resistant component in the reflection is D3. At this time, the actual physical distance D2 and the camera measured pixel distance D3 are calibrated to be the relationship between the current actual liquid surface distance and the industrial camera measured distance; Step S5: The crucible slowly descends 5 mm, and the camera captures an image of the high-temperature resistant component and its reflection in the liquid surface. Step S6: The pixel distance between the through hole of the high-temperature resistant component in the image and the through hole of the high-temperature resistant component in the reflection is D4. The pixel measurement value D5 corresponding to each decrease of 0.01 mm is calculated using the following formula: D5=(D4-D3) / 500; Step S7: inputting D5 into the controller, and calibrating D5 in the controller as the pixel change corresponding to each 0.01 mm drop of the actual crucible; Step S8: When the ingot is in the continuous growth process, the camera observes that the through-hole of the high-temperature resistant component and its reflection will change with the actual movement of the liquid level. The camera records the pixel distance D6 between the through-hole of the high-temperature resistant component and the through-hole of the high-temperature resistant component in the reflection in real time, and calculates the actual liquid level distance D7 using the formula D7 = D2 + (D6 - D3) / D5 * 0.01 to obtain real-time information on the movement of the liquid level. Step S9: Feedback the liquid level distance D7 to the controller, which compares the real-time liquid level distance D7 with the reference measurement value D0, and then performs the crucible lifting and lowering action according to the comparison result to adjust the liquid level position height.

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