Seed crystal lifting mechanism and crystal growth system

Abstract

The utility model discloses a seed crystal lifting mechanism and a crystal growth system. The lifting mechanism comprises a support, a sliding table, a rotating rod, a connecting structure and a weighing sensor, the sliding table is in sliding connection with the support in the axis direction of the rotating rod, and the rotating rod penetrates through the sliding table and rotates relative to the sliding table. The weighing sensor is located between the rotating rod and the connecting structure, connected with the rotating rod and synchronously rotates along with the rotating rod. The weighing sensor is connected with the sliding table through a connecting structure and is used for detecting the value of tension applied to the seed crystal by the rotating rod. One end of the rotating rod deviating from the weighing sensor is connected with a seed crystal. By adopting the lifting mechanism disclosed by the utility model, the height value between the seed crystal and the liquid level can be measured and calculated according to the tension value detected by the weighing sensor in real time, and the sliding table drives the rotating rod to slide relative to the bracket along the preset direction according to the height value, so that the stability of seeding quality is improved.

Description

Technical Field

[0001] The utility model relates to the field of crystal growth systems, in particular to a seed crystal pulling mechanism and a crystal growth system. Background Art

[0002] The third generation semiconductor silicon carbide (SiC) has the characteristics of wide bandgap, high breakdown voltage, large saturation drift velocity, high thermal conductivity, etc., which is conducive to the application of high voltage, high temperature and high frequency power devices. The prior art can produce single crystals of the third generation semiconductor SiC by solution growth method. One of the key steps of this process is seeding, which involves placing the seed crystal in the solution to guide the growth of new single crystals. The quality of seeding directly affects the quality of the crystal. However, the structure of the pulling mechanism of the seed crystal based on the existing solution growth method technology is complex and the control precision is low, and the seeding quality is unstable.

[0003] Therefore, how to improve the quality of seeding has become a difficult problem that needs to be solved urgently by those skilled in the art. Utility Model Content

[0004] The utility model provides a seed crystal pulling mechanism for improving the seed crystal quality.

[0005] In the first aspect, the utility model provides a seed crystal lifting mechanism, including a bracket, a slide, a rotating rod, a connecting structure and a weighing sensor, wherein the slide is slidably connected to the bracket along the axis direction of the rotating rod, the rotating rod passes through the slide, and rotates relative to the slide. Along the axis direction of the rotating rod, the weighing sensor is located between the rotating rod and the connecting structure, the weighing sensor is connected to the rotating rod, and rotates synchronously with the rotating rod. The weighing sensor is connected to the slide through the connecting structure. The end of the rotating rod away from the weighing sensor is used to connect the seed crystal, and the weighing sensor is used to detect the pulling force value applied by the rotating rod to the seed crystal. With the seed crystal lifting mechanism provided by the utility model, when the pulling force value detected by the weighing sensor is less than the weight of the seed crystal, the slide is slid relative to the bracket along a preset direction to make the seed crystal seed and form a crystal. At the same time, as the crystal on the seed crystal is continuously formed, the pulling force value detected by the weighing sensor will be greater than the weight of the seed crystal, and the slide will continue to slide relative to the bracket along the preset direction. As the crystal is continuously formed, when the tension value detected by the weighing sensor reaches or exceeds the preset tension value, the slide will stop moving in the preset direction, and the seed crystal seeding is finished. In addition, since the weighing sensor is connected to the slide through the connecting structure, when the slide slides relative to the bracket, the slide will drive the rotating rod, the weighing sensor and the connecting structure to slide relative to the bracket in the set direction. This can effectively improve the control accuracy of the lifting mechanism, thereby improving the stability of the seeding quality.

[0006] In a possible implementation manner of the present utility model, the lifting mechanism further includes a telescopic seal. The telescopic seal is located on the side of the sliding table away from the weighing sensor. The telescopic seal is sleeved on the rotating rod, and there is a gap between the inner side wall of the telescopic seal and the rotating rod. In addition, one end of the telescopic seal is hermetically connected to the sliding table, and the other end is used for hermetically connecting to the surface of the furnace cover of the crystal growth furnace. And the gap between the inner side wall of the telescopic seal and the rotating rod is in a vacuum state. Since the telescopic seal has the characteristics of being extensible and contractible, with such a design, the lifting mechanism can meet the requirements of crystal seeding under a vacuum state, and at the same time, the sliding table of the lifting mechanism can drive the rotating rod to move up and down along the axis direction of the rotating rod.

[0007] In a possible implementation manner of the present utility model, the lifting mechanism further includes a mounting plate, the material of which is a high-temperature resistant material, and it can withstand a temperature higher than the outer surface temperature of the crystal growth furnace. The mounting plate is located on the side of the telescopic seal away from the weighing sensor, and the telescopic seal is hermetically connected to the surface of the furnace cover of the crystal growth furnace through the mounting plate. This is beneficial to extending the service life of the sealable telescopic member.

[0008] In a possible implementation manner of the present utility model, the telescopic seal is a corrugated pipe. This can reduce the production cost while meeting the functional requirements of the lifting mechanism.

[0009] In a possible implementation manner of the present utility model, the connection structure includes a stator and a rotor sleeved with each other. The stator is fixedly connected to the sliding table, and is sealed between the stator and the sliding table. At the same time, a cavity is formed between the stator and the sliding table, and the inside of this cavity is in a vacuum state. The rotor is connected to the weighing sensor, and the weighing sensor is located inside the above-mentioned vacuum cavity. At the same time, the vacuum cavity is in communication with the vacuum gap formed between the corrugated pipe and the rotating rod, so as to form a connected vacuum cavity. In this way, the lifting mechanism can meet the requirements of crystal seeding under a vacuum state, and at the same time, the structure of the lifting mechanism is more concise.

[0010] In a possible implementation manner of the present utility model, the lifting mechanism further includes an adjustment structure and a locking structure. Along the axis direction of the rotating rod, the adjustment structure is located between the stator and the sliding table and is fixedly connected to the stator. Along the axis direction of the rotating rod, the adjustment structure is provided with a mounting hole, and the locking structure is in clearance fit with the mounting hole. The adjustment structure is connected to the sliding table through the locking structure. In this way, before crystal seeding, by moving the adjustment mechanism along the direction perpendicular to the axis of the rotating rod, the seed crystal on the rotating rod can be aligned with the center of the furnace body of the crystal growth furnace, and the adjusted adjustment structure is connected to the sliding table through the locking structure, thereby improving the crystal seeding quality of the lifting mechanism.

[0011] In a possible implementation manner of the present utility model, the bracket includes a guide rail, and the sliding table is slidably connected to the guide rail. This is beneficial to reducing the resistance between the sliding table and the bracket during the movement of the sliding table, thereby improving the operation convenience of the lifting mechanism.

[0012] In a possible implementation manner of the present utility model, the lifting mechanism further includes a first driving device and a second driving device. The first driving device is used to drive the sliding table to slide along the guide rail; the second driving device is used to drive the rotating shaft to rotate. This can effectively improve the automation degree of the lifting mechanism.

[0013] In a possible implementation manner of the present utility model, the lifting mechanism further includes a slip ring, and the slip ring is electrically connected to the weighing sensor. During the rotation of the weighing sensor, the electric slip ring can transmit the signal obtained by the weighing sensor to the electric control box in a rotating state, and during the rotation process, it can be used to prevent the cables for transmitting signals and electric energy from being twisted and damaged. Thereby improving the reliability of the lifting structure.

[0014] In a second aspect, the present utility model further provides a crystal growth system. The crystal growth system includes the seed crystal lifting mechanism of the first aspect, and the bracket is installed on the surface of the furnace cover of the crystal growth furnace. By using the crystal growth system provided by the present utility model, during the crystal seeding process, the rotating rod can drive the seed crystal to pass through the furnace cover and enter the furnace body of the crystal growth furnace. And when the pulling force value detected by the weighing sensor is less than the weight of the seed crystal, by making the sliding table slide relative to the bracket along a preset direction, the seed crystal starts to grow crystals; at the same time, as the crystals on the seed crystal continue to form, the pulling force value detected by the weighing sensor will be greater than the weight of the seed crystal, and the sliding table will continue to slide relative to the bracket along the preset direction. As the crystals continue to form, when the pulling force value detected by the weighing sensor reaches or is greater than the preset pulling force value, the sliding table will stop moving along the preset direction, and at this time, the crystal seeding of the seed crystal ends.

[0015] In addition, since the weighing sensor is connected to the sliding table through a connecting structure, therefore, while the sliding table slides relative to the bracket, the sliding table will drive the rotating rod, the weighing sensor and the connecting structure to slide relative to the bracket along the preset direction together. In this way, by using the seed crystal lifting mechanism provided by the present utility model, the automation degree and control precision of the lifting mechanism can be effectively improved, thereby improving the stability of the crystal seeding quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A structural schematic diagram of the seed crystal lifting mechanism provided by the present utility model;

[0017] Figure 2 is Figure 1 A sectional view of the provided lifting mechanism;

[0018] Figure 3 isFigure 2 Partial enlarged view of location A of the provided lifting mechanism.

[0019] Reference numerals: 1 - bracket; 11 - guide rail; 2 - slide table; 3 - rotating rod; 4 - connecting structure; 41 - stator; 42 - rotor; 5 - weighing sensor; 6 - slip ring; 7 - telescopic seal; 8 - mounting plate; 9 - adjusting structure; 91 - mounting hole; 010 - locking structure; 011 - first driving device; 0111 - first motor; 012 - second driving device; 0121 - wedge belt; 0122 - large pulley; 0123 - small pulley. Detailed implementation manners

[0020] In order to make the objectives, technical solutions and advantages of the present utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings. However, the exemplary embodiments can be implemented in various forms and should not be construed as being limited to the embodiments described herein. Identical reference numerals in the drawings denote identical or similar structures, and thus their repeated description will be omitted. The words expressing positions and directions described in the embodiments of the present utility model are illustrative with reference to the drawings, but can be changed according to needs, and all the changes are included in the protection scope of the present utility model. The drawings in the embodiments of the present utility model are only used to illustrate the relative positional relationship, and they do not represent the actual proportion.

[0021] It should be noted that specific details are set forth in the following description to facilitate understanding of the present utility model. However, the present utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the connotation of the present utility model. Therefore, the present utility model is not limited by the specific implementation manners disclosed below.

[0022] The third-generation semiconductor silicon carbide (SiC) has characteristics such as a wide bandgap, high breakdown voltage, large saturation drift velocity, and high thermal conductivity, which are beneficial to the application of high-voltage, high-temperature, and high-frequency power devices. The prior art can produce single crystals of the third-generation semiconductor SiC by solution growth method. One of the key steps of this process is crystal seeding, which involves placing a seed crystal in a solution to guide the growth of a new single crystal, and the quality of crystal seeding directly affects the quality of the crystal. However, the control accuracy of the seed crystal lifting mechanism of the existing solution growth method technology is low, and the quality of crystal seeding is unstable.

[0023] In view of this, the seed crystal lifting mechanism provided by the present utility model optimizes the structure of the lifting mechanism, and enables the sensor to obtain the weight of the seed crystal to determine the moment when the seed crystal contacts the liquid surface of crystal growth initiation and the moment when crystal growth initiation is completed, so as to accurately control the movement of the rotating rod and other components and the rotation of the rotating rod, thereby improving the stability of the quality of crystal growth initiation. In order to make the objectives, technical solutions, and advantages of the present utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0024] Reference Figure 1 , Figure 1 is a schematic structural diagram of a seed crystal lifting mechanism provided by the present utility model. The seed crystal lifting mechanism includes a bracket 1, a sliding table 2, a rotating rod 3, a connecting structure 4, and a weighing sensor 5. Among them, along the axial direction of the rotating rod 3 (such as Figure 1 the Z-axis direction shown), the sliding table 2 is slidably connected to the bracket 1, the rotating rod 3 passes through the sliding table 2, and the rotating rod 3 rotates relative to the sliding table 2.

[0025] In addition, referring to Figure 2 , Figure 2 is Figure 1 a sectional view of the lifting mechanism provided. Along the axial direction of the rotating rod 3 (such as Figure 2 the Z-axis direction shown), the weighing sensor 5 is located between the rotating rod 3 and the connecting structure 4. The weighing sensor 5 is connected to the rotating rod 3 and rotates synchronously with the rotating rod 3, which can avoid the wires of the electrical connection between the weighing sensor 5 and the rotating rod 3 from being broken. And one end of the rotating rod 3 away from the weighing sensor 5 is used to connect the seed crystal, and the weighing sensor 5 is used to detect the pulling force value applied by the rotating rod 3 to the seed crystal in real time, thereby improving the data detection accuracy.

[0026] When the pulling force value detected by the weighing sensor 5 is less than the weight of the seed crystal, that is, when the seed crystal contacts the liquid surface, the sliding table 2 can slide relative to the bracket 1 in a preset direction to initiate crystal growth of the seed crystal and form a crystal; at the same time, as the crystal on the seed crystal continues to form, the pulling force value detected by the weighing sensor 5 will be greater than the weight of the seed crystal, and the sliding table 2 will also continue to slide relative to the bracket 1 in the preset direction. As the crystal continues to form, when the pulling force value detected by the weighing sensor 5 reaches or is greater than the preset pulling force value, the sliding table 2 will stop moving in the preset direction, and at this time, the crystal growth initiation of the seed crystal ends. Among them, the preset pulling force value = the weight of the crystal formed when crystal growth initiation is completed + the weight of the seed crystal.

[0027] In addition, since the weighing sensor 5 is connected to the slide 2 through the connecting structure 4, when the slide 2 slides along the preset direction relative to the bracket 1, the slide 2 will drive the rotating rod 3, the weighing sensor 5 and the connecting structure 4 to slide along the preset direction relative to the bracket 1. In this way, the seed crystal lifting mechanism provided by the utility model can effectively improve the control accuracy of the lifting mechanism, thereby improving the stability of the seed crystal quality.

[0028] It should be noted that the slide table 2 can control the movement or stop of the slider 2 relative to the bracket 1 by manually controlling an electric control switch.

[0029] In addition, in a specific embodiment, the lifting mechanism may further include a control module, and the control module is used to control the sliding displacement of the slide relative to the bracket according to the pulling force value detected by the weighing sensor.

[0030] Continue to refer Figure 2 The lifting mechanism also includes a retractable seal 7, which is located on the side of the slide 2 away from the weighing sensor 5, and the retractable seal 7 is sleeved on the rotating rod 3. It should be noted that the retractable seal 7 can be a tubular structure, and a gap is left between the inner wall of the tubular structure and the outer wall of the rotating rod 3. One end of the retractable seal 7 is connected to the slide 2, and the retractable seal 7 and the slide 2 are sealed; the other end is used to connect to the surface of the furnace cover of the crystal growth furnace, and the retractable seal 7 and the crystal growth furnace are sealed, and the gap between the inner wall of the tubular structure and the outer wall of the rotating rod 3 is in a vacuum state.

[0031] In addition, during the crystal induction process, since the end of the rotating rod 3 connected to the seed crystal needs to pass through the furnace cover of the crystal growth furnace and extend into the furnace body of the crystal growth furnace, the crystal grown on the seed crystal can be prevented from being oxidized by setting the gap between the inner wall of the tubular structure and the outer wall of the rotating rod 3 to a vacuum state.

[0032] Since the retractable seal 7 has the characteristics of being extendable and retractable, such a design can enable the pulling mechanism to meet the requirements of crystal seeding under vacuum conditions while also enabling the slide 2 of the pulling mechanism to drive the rotating rod 3 to rise and fall along the Z axis.

[0033] The present invention does not specifically limit the retractable sealing member 7. For example, the retractable sealing member 7 is a bellows, so as to reduce the production cost while meeting the functional requirements of the lifting mechanism.

[0034] It is worth mentioning that Figure 1As shown, the lifting mechanism also includes a mounting plate 8, which is located on the side of the retractable seal 7 away from the weighing sensor 5, and is made of a high temperature resistant material that can withstand a temperature higher than the outer surface temperature of the crystal growth furnace. The retractable seal 7 is connected to the surface of the furnace cover of the crystal growth furnace through the mounting plate 8, and the retractable seal 7 and the mounting plate 8, as well as the mounting plate 8 and the crystal growth furnace, are sealed, which is conducive to extending the service life of the sealable retractable member.

[0035] In a specific embodiment, referring to Figure 3 , Figure 3 for Figure 2 A partial enlarged view of the A of the lifting mechanism provided. The connection structure 4 includes a stator 41 and a rotor 42 which are connected to each other, the stator 41 is fixedly connected to the slide 2, and the stator 41 is sealed with the slide 2, and a cavity is formed between the stator and the slide, and the cavity is in a vacuum state. The rotor 42 is connected to the weighing sensor 5 to realize the synchronous rotation of the weighing sensor 5 and the rotating rod 3, and the weighing sensor 5 is located in the above-mentioned vacuum cavity, and the vacuum cavity is interconnected with the vacuum gap formed between the bellows and the rotating rod 3, so as to form a connected vacuum cavity, so that the lifting mechanism can meet the requirements of seeding under vacuum state while making the structure of the lifting mechanism more concise. Exemplarily, the connection structure 4 can be a magnetic fluid, and the stator 41 of the magnetic fluid is sealed with the rotor 42.

[0036] Continue to refer Figure 3 The lifting mechanism also includes an adjustment structure 9 and a locking structure 010. Along the axial direction of the rotating rod 3, the adjustment structure 9 is located between the stator 41 and the slide 2 and is fixedly connected to the stator 41.

[0037] Along the axis direction of the rotating rod 3, the adjustment structure 9 is provided with a mounting hole 91, and the locking structure 010 is in clearance with the mounting hole 91, that is, the adjustment mechanism has floating space in the direction perpendicular to the Z axis. Before seeding, the adjustment mechanism is moved in the direction perpendicular to the Z axis so that the seed crystal on the rotating rod 3 is aligned with the center of the furnace body of the crystal growth furnace, and the adjusted adjustment structure 9 is connected to the slide 2 through the locking structure 010, thereby improving the seeding quality of the pulling mechanism.

[0038] The present invention does not limit the specific forms of the adjustment structure 9 and the locking structure 010. For example, the adjustment structure 9 can be a plate-like structure, and the mounting hole 91 passes through the plate surface of the plate-like structure. This structural method is simple and easy to produce and process.

[0039] In addition, the locking structure 010 can be a screw, and a threaded hole corresponding to the screw is provided on the slide 2.

[0040] Continue to refer Figure 1The bracket 1 includes a guide rail 11, and the slide 2 is slidably connected to the guide rail 11. This is conducive to reducing the resistance between the slide 2 and the bracket 1 during the movement of the slide 2, thereby improving the convenience of operation of the lifting mechanism.

[0041] In a specific embodiment, Figure 1 As shown, the lifting mechanism also includes a first driving device 011 and a second driving device 012. The first driving device 011 is used to drive the slide 2 to slide along the guide rail 11, and the second driving device 012 is used to drive the rotating shaft to rotate. The first driving device 011 includes a first motor 0111, a differential and a worm gear reducer. Specifically, the output shaft of the first motor 0111 is connected to the worm gear reducer through the differential, and the output end of the worm gear reducer is connected to the slider, the slider is fixedly connected to the slide 2, and the slider is slidably connected to the slide rail.

[0042] In addition, if Figure 2 As shown, the second driving device 012 includes a second motor 0121, a reducer, a reducer mounting frame, a wedge-shaped belt 0122, a large pulley 0123 and a small pulley 0124. Specifically, the output end of the second motor 0121 is connected to the reducer, and the reducer is fixedly mounted on the bracket 1 through the reducer mounting frame. In addition, the output shaft of the reducer is connected to the small pulley 0124, the large pulley 0123 is sleeved with the rotor 42, and the large pulley 0123 is connected to the small pulley 0124 through the wedge-shaped belt 0122, thereby realizing the synchronous rotation of the weighing sensor 5 and the rotating rod 3, and improving the automation degree of the lifting mechanism.

[0043] like Figure 1 As shown, the lifting mechanism also includes a slip ring 61, which is electrically connected to the weighing sensor 5 and the control box. During the rotation of the weighing sensor 5, the slip ring can transmit the signal obtained by the weighing sensor 5 to the display screen of the control box, which can be used to prevent the cable that transmits the signal and electric energy from being twisted and damaged. Thereby improving the reliability of the lifting structure.

[0044] After understanding the specific structure of the pulling mechanism provided by the utility model, the following is a detailed description of the specific method of using the pulling mechanism provided by the utility model to complete seeding in a crystal growth system, taking the liquid phase SiC (silicon carbide) crystal growth process as an example in combination with actual application scenarios:

[0045] First, the support 1 of the lifting mechanism is placed on the furnace cover of the crystal growth system, and the rotating rod 3 with the seed crystal is extended into the furnace body of the crystal growth furnace, and the furnace body is filled with silicon carbide raw materials, and the mounting plate 8 is fixed to the above-mentioned furnace cover.

[0046] Immediately after the silicon carbide raw material in the furnace body melts, the control device controls the first driving device 011 to drive the rotating rod 3 through the sliding table 2 to quickly lower the seed crystal to a position 10 mm above the surface of the melt, so that the high-temperature solution bakes the seed crystal. Before crystal seeding, it is considered that the solution vapor solidifies on the surface of the seed crystal and etches the surface of the seed crystal. It should be noted that the weight change of the seed crystal at this time can be ignored. Subsequently, locally saturated SiC in the solution can be deposited again, thereby forming 15R-SiC, Si droplets, and viscous SiC particles.

[0047] Immediately afterwards, as the deposition of SiC continues, the first driving device 011 drives the rotating rod 3 to slowly drive the seed crystal into the solution. At the same time, the second driving device 012 drives the rotating rod 3 to rotate.

[0048] Immediately afterwards, when the tensile force value detected by the weighing sensor 5 is less than the weight of the seed crystal, the rotating rod 3 is lifted from the surface of the solution to a certain height to form a meniscus of 0.2 - 3.5 mm. During the crystal seeding process, the crystal continuously grows and gains weight, and the silicon carbide solution continuously decreases, so the liquid level height in the furnace body continuously decreases. The first driving device 011 and the second driving device 012 drive the rotating rod 3 to move and rotate along the Z-axis direction to improve the stability of the crystal seeding quality.

[0049] In summary, for the lifting mechanism provided by the present utility model, when the tensile force value detected by the weighing sensor 5 is less than the weight of the seed crystal, that is, when the seed crystal contacts the liquid surface, the sliding table 2 slides relative to the bracket 1 along a preset direction, so that the seed crystal seeds and forms a crystal; at the same time, as the crystal on the seed crystal continuously forms, the tensile force value detected by the weighing sensor 5 will be greater than the weight of the seed crystal, and the sliding table 2 will also continue to slide relative to the bracket 1 along the preset direction. As the crystal continuously forms, when the tensile force value detected by the weighing sensor 5 reaches or is greater than the preset tensile force value, the sliding table 2 will stop moving along the preset direction, and at this time, the crystal seeding of the seed crystal ends.

[0050] In addition, since the weighing sensor 5 is connected to the sliding table 2 through the connecting structure 4, therefore, while the sliding table 2 slides relative to the bracket 1 along the preset direction, the sliding table 2 will drive the rotating rod 3, the weighing sensor 5, and the connecting structure 4 to slide relative to the bracket 1 along the preset direction together. In this way, by adopting the lifting mechanism of the seed crystal provided by the present utility model, the control accuracy of the lifting mechanism can be effectively improved, and thus the stability of the crystal seeding quality can be improved.

[0051] Obviously, those skilled in the art can make various modifications and variations to the present utility model without departing from the spirit and scope of the present utility model. In this way, provided that these modifications and variations of the present utility model fall within the scope of the claims of the present utility model and their equivalent technologies, the present utility model also intends to include these modifications and variations.

Claims

1. A seed crystal pulling mechanism, characterized in that: It includes a bracket, a slide, a rotating rod, a connecting structure and a weighing sensor, wherein: Along the axis direction of the rotating rod, the slide is slidably connected to the bracket, and the rotating rod passes through the slide and rotates relative to the slide; Along the axis direction of the rotating rod, the weighing sensor is located between the rotating rod and the connecting structure, the weighing sensor is connected to the rotating rod, and rotates synchronously with the rotating rod; the weighing sensor is connected to the slide table through the connecting structure; One end of the rotating rod facing away from the weighing sensor is used to connect with the seed crystal, and the weighing sensor is used to detect the pulling force value applied by the rotating rod to the seed crystal.

2. The seed crystal pulling mechanism according to claim 1, characterized in that: The lifting mechanism also includes a retractable seal, which is located on the side of the slide away from the weighing sensor; the retractable seal is sleeved on the rotating rod, and there is a gap between the inner wall of the retractable seal and the rotating rod; and one end of the retractable seal is sealed to the slide, and the other end is used for sealing connection with the surface of the furnace cover of the crystal growth furnace.

3. The seed crystal pulling mechanism according to claim 2, characterized in that: The lifting mechanism further comprises a mounting plate, which is located on a side of the retractable seal away from the weighing sensor; the retractable seal is sealingly connected to the surface of the furnace cover of the crystal growth furnace through the mounting plate.

4. The seed crystal pulling mechanism according to claim 2 or 3, characterized in that: The retractable sealing element is a bellows.

5. The seed crystal pulling mechanism according to claim 2, characterized in that: The connection structure comprises a stator and a rotor which are sleeved together. The stator is fixedly connected to the slide, and a seal is formed between the stator and the slide; the rotor is connected to the weighing sensor.

6. The seed crystal pulling mechanism according to claim 5, characterized in that: The lifting mechanism further includes an adjustment structure and a locking structure. Along the axis direction of the rotating rod, the adjustment structure is located between the stator and the slide table and is fixedly connected to the stator. The adjustment structure is provided with a mounting hole along the axis direction of the rotating rod, and the locking structure is loosely matched with the mounting hole; the adjustment structure is connected to the slide table through the locking structure.

7. The seed crystal pulling mechanism according to claim 1, characterized in that: The bracket comprises a guide rail, and the slide is slidably connected to the guide rail.

8. The seed crystal pulling mechanism according to claim 7, characterized in that: The lifting mechanism further includes a first driving device and a second driving device, wherein the first driving device is used to drive the slide to slide along the guide rail; and the second driving device is used to drive the rotating shaft to rotate.

9. The seed crystal pulling mechanism according to claim 1, characterized in that: The lifting mechanism further includes a slipping electric ring, and the slipping electric ring is electrically connected to the weighing sensor.

10. A crystal growth system, characterized in that: The invention comprises a crystal growth furnace and a pulling mechanism as claimed in any one of claims 1 to 9, wherein the bracket is installed on the surface of a furnace cover of the crystal growth furnace.

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