High-precision liquid level moving position measuring assembly and measuring method

Abstract

The invention discloses a high-precision liquid level moving position measuring assembly and method, and the assembly comprises a crucible which is filled with a silicon liquid; the guide cylinder is arranged above the silicon liquid, and a high-temperature-resistant component is arranged at the bottom of the guide cylinder; the crystal bar cooling device is arranged above the silicon liquid, the crystal bar cooling device is arranged in the guide cylinder, and a plurality of crystal pulling holes are formed in the bottom of the crystal bar cooling device; the camera is used for acquiring the high-temperature-resistant component and the image of the inverted image of the high-temperature-resistant component on the silicon liquid level; the controller is used for receiving and processing data transmitted by the camera; a protrusion is arranged on the high-temperature-resistant component, and a through hole is formed in the protrusion. The high-precision liquid level moving position measuring assembly and the measuring method are convenient to use, through camera measurement and controller control, the moving positions of the bottom of a crystal bar cooling device and the liquid level of raw material silicon liquid are measured and controlled in real time, and therefore the diameter of a crystal bar can be controlled.

Description

Technical Field

[0001] The 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-crystalline / monocrystalline silicon is an important raw material for industries such as semiconductors and photovoltaics. In the process of producing multi-crystalline / monocrystalline silicon, the amount of silicon cores used is very large. The most advanced silicon core preparation currently uses a multi-turn vertical pull crystal growth furnace to directly pull multiple silicon cores. The principle is to heat and melt the raw materials into a liquid state, and then use seed crystals to seed the liquid raw materials to recrystallize and form the required silicon core. In order to maintain stable crystal growth of the silicon core and control the size of the crystal rod diameter, it is necessary to ensure that the speed and position accuracy of the liquid level movement during the preparation process are appropriate, so that the distance between the bottom of the silicon core cooling device and the silicon liquid level is always at a suitable and stable distance. Therefore, how to measure the position of the liquid level movement is crucial for the stable growth of the silicon core.

[0003] At present, the industry generally adopts horizontal measurement as the way of measuring the movement position of liquid surface by visual system. This method cannot linearly show the change of the movement position of liquid surface. The original technology has poor accuracy and large fluctuation, and cannot achieve accurate control of liquid surface position. Some adopt specific angles for oblique measurement, but this angle is affected by the installation angle of the measuring camera. The crystal rod needs to be produced for the first time to obtain the specific angle value. There is no physical calibration of the actual liquid surface position. The change of the actual movement position of liquid surface is judged manually based on experience, which is greatly affected 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 purpose of the present invention is to provide a high-precision liquid level movement position measurement component and measurement method. 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, to achieve real-time measurement and control of the movement position of the bottom of the crystal rod cooling device and the raw silicon liquid surface, so as to control the diameter of the crystal rod.

[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 rod cooling device, wherein the crystal rod cooling device is arranged above the silicon liquid and in the guide tube, and a plurality of crystal pulling holes are opened at the bottom of the crystal rod cooling device;

[0011] A camera, used to obtain 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 purpose of the present invention is to provide a high-precision liquid level movement position measurement component and measurement method. 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, to achieve real-time measurement and control of the movement position of the bottom of the crystal rod cooling device and the raw silicon liquid surface, so as to control the diameter of the crystal rod.

[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 comprises a silicon liquid contact piece and a signal amplifier which 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 component comprises the following steps:

[0020] Step S1: preset a reference measurement value D0 in the controller, and when the liquid level position is confirmed for the first time, slowly raise the crucible. When the controller detects the output voltage of the electrostatic capacitance detection device, the crucible is immediately stopped from rising;

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

[0022] D2=(L1+D1)

[0023] Wherein, L1 is the protruding length of the electrostatic capacitance detection device, and D1 is the distance the crucible descends after the electrostatic capacitance detection device contacts the liquid surface;

[0024] Step S3: After the liquid surface is stable, the camera takes 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 measurement pixel distance D3 are calibrated as the relationship between the current actual liquid surface distance and the industrial camera measurement distance;

[0026] Step S5: the crucible slowly descends 5 mm, and the camera captures the 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, and the pixel measurement value D5 corresponding to each decrease of 0.01 mm is calculated, and the calculation formula is:

[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 crystal rod is in the process of continuous growth, the through hole of the high temperature resistant component and its reflection observed by the camera will change with the actual movement of the liquid surface position. The camera records the pixel distance between the through hole of the high temperature resistant component and the through hole of the high temperature resistant component in the reflection as D6 in real time, and calculates the actual liquid surface distance D7 by the formula D7=D2+(D6-D3) / D5*0.01 to obtain the real-time information of the liquid surface movement position;

[0031] 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, and then perform 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 naked eye observation.

[0034] 2. The through holes are set on the high temperature resistant parts, which is conducive to the accuracy of target feature extraction of visual measurement and achieves higher measurement accuracy. It avoids the problems of poor reflection of traditional graphite materials, difficult feature extraction, and easy generation of oxides.

[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 lifting and lowering 0.01 mm are calibrated respectively, so that 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 of the crucible to adjust the liquid level position, and realizes 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, so as to control 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 A schematic diagram of the local enlarged structure at point A in the middle;

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

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

[0041] In order to enable those skilled in the art to better understand the technical solution of the present invention, the preferred implementation scheme of the present invention is described below in conjunction with specific embodiments. However, it should be understood that the drawings are only used for exemplary description and cannot be understood as a limitation on this patent. In order to better illustrate this embodiment, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of the actual product. For those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted. The positional relationship described in the drawings is only for exemplary description and cannot be understood as a limitation on this patent.

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

[0043] Embodiment 1:

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

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

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

[0047] A crystal rod cooling device 4, wherein the crystal rod cooling device 4 is disposed above the silicon liquid 2 and in the guide tube 3, and a plurality of crystal pulling holes 41 are provided at the bottom of the crystal rod 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] A controller, used for receiving and processing 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 crystal rod cooling device 4 is used to cool the crystal rod, and the crystal rod is placed in the crystal pulling hole 41. The crucible 1 is usually equipped with a lifting device at the bottom. The controller controls the lifting of the crucible 1, which belongs to the prior art and will not be described in detail.

[0052] Embodiment 2:

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

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

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

[0056] A crystal rod cooling device 4, wherein the crystal rod cooling device 4 is disposed above the silicon liquid 2 and within the guide tube 3, and a plurality of crystal pulling holes 41 are provided at the bottom of the crystal rod 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] A controller, used for receiving and processing 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] Further, in another embodiment, the electrostatic capacitance detection device comprises a silicon liquid contact 7 and a signal amplifier which are 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 turned on, forming a closed loop.

[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] Among them, PH is connected to the PLC analog input port. The detection principle is to apply voltage between 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, and the current direction is: 24V→20K→A10P→5.26K→A10N→24N. There is no voltage output at the PH end of the detection device. When the silicon liquid contact 7 is in contact with the silicon liquid surface, the PH end circuit of the detection device is closed and outputs 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 size of its 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: preset a reference measurement value D0 in the controller, and when the liquid level position is confirmed for the first time, slowly raise the crucible 1. When the controller detects that the electrostatic capacitance detection device outputs a voltage, that is, when the electrostatic capacitance detection device is just 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 rod 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, and D1 is the distance that the crucible 1 descends after the electrostatic capacitance detection device contacts the liquid surface;

[0072] Step S3: After the liquid surface is stable, the camera 5 takes 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 as the relationship between the current actual liquid surface distance and the distance measured by the industrial camera 5;

[0074] Step S5: the crucible 1 slowly descends 5 mm, and the camera 5 takes 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, and the pixel measurement value D5 corresponding to each decrease of 0.01 mm is calculated, and the calculation formula is:

[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 crystal rod is in the process of continuous growth, the through hole 62 of the high temperature resistant component 6 and its reflection observed by the camera 5 will change with the actual movement of the liquid surface position. The camera 5 records in real time the pixel distance 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 as D6, and calculates the actual liquid surface distance D7 by the formula D7=D2+(D6-D3) / D5*0.01, thereby obtaining the real-time information of the liquid surface movement position;

[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, and then lift the crucible 1 according to the comparison result, adjust the liquid level position height, so that the crystal growth rate matches the liquid level movement position speed. During the entire crystal pulling process, the liquid level movement position is always compared and adjusted 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, the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicating orientation or positional relationships are based on the orientation or positional relationships shown in the drawings, which 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 relationship in the present invention are only used for illustrative purposes and cannot be understood as limitations on this patent. For ordinary technicians in this field, the specific meanings of the above terms can be understood in conjunction with the drawings and according to specific circumstances.

[0082] Unless otherwise clearly specified and limited, in the present invention, the terms "disposed", "connected" and "connected" 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 the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to 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 protection scope 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 rod cooling device, wherein the crystal rod cooling device is arranged above the silicon liquid and in the guide tube, and a plurality of crystal pulling holes are opened at the bottom of the crystal rod cooling device; A camera, used to obtain 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.

2. The high-precision liquid level movement position measuring assembly according to claim 1, characterized in that: A static capacitance detection device is provided at the bottom of the crystal rod cooling device.

3. The high-precision liquid level movement position measuring assembly according to claim 2, characterized in that: The electrostatic capacitance detection device comprises a silicon liquid contact piece and a signal amplifier which are electrically connected in sequence, wherein 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 a controller.

4. The high-precision liquid level movement position measuring assembly according to claim 3, characterized in that: 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.

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

6. A method for measuring a high-precision liquid level movement position measuring assembly according to any one of claims 1 to 5, characterized in that: The following steps are involved: Step S1: preset a reference measurement value D0 in the controller, and when the liquid level position is confirmed for the first time, slowly raise the crucible. When the controller detects the output voltage of the electrostatic capacitance detection device, the crucible is immediately stopped from rising; Step S2: The crucible is then lowered by a distance D1. At this time, the physical distance between the bottom of the crystal rod cooling device and the liquid surface is D2, and the calculation formula is: D2=(L1+D1) Wherein, L1 is the protruding length of the electrostatic capacitance detection device, and D1 is the distance the crucible descends after the electrostatic capacitance detection device contacts the liquid surface; Step S3: After the liquid surface is stable, the camera takes 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 measurement pixel distance D3 are calibrated as the relationship between the current actual liquid surface distance and the industrial camera measurement distance; Step S5: the crucible slowly descends 5 mm, and the camera captures the 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, and the pixel measurement value D5 corresponding to each decrease of 0.01 mm is calculated, and the calculation formula is: 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 crystal rod is in the process of continuous growth, the through hole of the high temperature resistant component and its reflection observed by the camera will change with the actual movement of the liquid surface position. The camera records the pixel distance between the through hole of the high temperature resistant component and the through hole of the high temperature resistant component in the reflection as D6 in real time, and calculates the actual liquid surface distance D7 by the formula D7=D2+(D6-D3) / D5*0.01 to obtain the real-time information of the liquid surface movement position; 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, and then perform the crucible lifting and lowering action according to the comparison result to adjust the liquid level position height.

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