Single crystal furnace

Abstract

The utility model discloses a single crystal furnace and belongs to the technical field of monocrystalline silicon preparation. The single crystal furnace comprises a furnace body, a lifting system, a large crucible and a plurality of small crucibles, wherein the lifting system is arranged in an auxiliary chamber of the furnace body; the lifting system comprises a plurality of seed crystal connecting pieces; each seed crystal connecting piece is used for connecting one seed crystal; a through hole is formed in the bottom of each small crucible; the plurality of small crucibles are positioned and nested in the large crucible and are communicated with the large crucible through the through holes; the central axis of each small crucible corresponds to one seed crystal connecting piece, so that the seed crystals connected with the seed crystal connecting pieces coincide with the central axes of the small crucibles; and the lifting system and the large crucible are coaxial and rotate in the same direction. The single crystal furnace can solve the problem of large temperature difference of the silicon liquid level, can block convection generated by rotation of the large crucible, and can improve the quality of silicon rods while improving the production efficiency of the silicon rods.

Description

Technical Field

[0001] The utility model relates to the technical field of single crystal silicon preparation, in particular to a single crystal furnace. Background Art

[0002] Currently, single crystal furnaces designed to simultaneously pull multiple silicon ingots have been designed to improve silicon pulling efficiency. Multiple seed crystals are introduced into the furnace and simultaneously contact the silicon liquid level within the same crucible. By controlling the furnace temperature and seed crystal pulling, multiple ingots are simultaneously pulled. To meet silicon material demand, existing processes for simultaneously pulling multiple silicon ingots or single crystal furnaces use a relatively large-diameter crucible to provide silicon liquid for the multiple seed crystals.

[0003] Increasing the crucible diameter increases the temperature variation of the silicon liquid surface, which can lead to significant variations between individual silicon rods. In severe cases, this can prevent or interrupt the pulling process. Furthermore, the crucible's rotation generates strong convection in the silicon liquid, which can also affect the pulling process. Therefore, existing processes for simultaneously pulling multiple silicon rods or single crystal furnaces still have significant room for improvement. Utility Model Content

[0004] In view of this, the present invention provides a single crystal furnace. The single crystal furnace is designed with multiple small crucibles connected to a large crucible. Each small crucible is provided with a corresponding seed crystal. This can solve the problem of large temperature differences in the silicon liquid surface and block the convection generated by the rotation of the large crucible. While improving the production efficiency of silicon rods, it can also improve the quality of silicon rods. Specifically, the following technical solutions are included:

[0005] A single crystal furnace comprises a furnace body, a lifting system, a large crucible and a plurality of small crucibles, wherein:

[0006] The lifting system is arranged in the auxiliary chamber of the furnace body;

[0007] The lifting system includes a plurality of seed crystal connecting members;

[0008] Each of the seed crystal connectors is used to connect a seed crystal;

[0009] Each of the small crucibles is provided with a through hole at the bottom;

[0010] The plurality of small crucibles are positioned and nested in the large crucible and are connected to the large crucible through the through hole;

[0011] The central axis of each of the small crucibles corresponds to one of the seed crystal connectors, so that the seed crystal connected to the seed crystal connector coincides with the central axis of the small crucible;

[0012] The lifting system is coaxial with the large crucible and rotates in the same direction.

[0013] The technical scheme provided by the utility model has the following advantages or beneficial effects:

[0014] The single crystal furnace provided by the embodiment of the utility model can simultaneously connect and pull a plurality of seed crystals through the plurality of seed crystal connecting pieces included in the lifting system, so as to synchronously draw a plurality of crystal silicon rods, the single crystal furnace provides silicon liquid for drawing each crystal silicon rod through the plurality of relatively independent small crucibles nested in the large crucible, can solve the problem of large temperature difference of the liquid surface of the silicon liquid used for drawing each crystal silicon rod, and can block the convection generated by the rotation of the large crucible, so as to improve the production efficiency of the silicon rod and improve the quality of the silicon rod. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 It is a single crystal furnace cross section structure schematic diagram provided according to the embodiment of the utility model;

[0016] Figure 2 It is a three-dimensional structure front view of the relative relationship between the first lifting system, the large crucible and the small crucible in the single crystal furnace according to the embodiment of the utility model;

[0017] Figure 3 It is a three-dimensional structure top view at a certain angle of the relative relationship between the first lifting system, the large crucible and the small crucible in the single crystal furnace according to the embodiment of the utility model;

[0018] Figure 4 It is a three-dimensional structure top view at a certain angle of the relative relationship between the second lifting system, the large crucible and the small crucible in the single crystal furnace according to the embodiment of the utility model;

[0019] Figure 5 It is a three-dimensional structure schematic diagram of the lifting mechanism according to the embodiment of the utility model;

[0020] Figure 6 It is a top view of the small crucible according to the embodiment of the utility model;

[0021] Figure 7 It is a schematic diagram of the relative relationship between the load balancing turntable and the connecting rod according to the embodiment of the utility model.

[0022] The reference signs are as follows:

[0023] 10-furnace body;20-lifting system;21-seed crystal connecting piece;22-load balancing turntable;221-rotating shaft mounting portion;23-lifting mechanism;231-first rotating shaft;232-second rotating shaft;233-pulling rope;30-large crucible;40-small crucible;41-second limiting portion;50-connecting rod;60-heater;70-water-cooled heat shield;80-supporting structure;90-seed crystal. DETAILED DESCRIPTION

[0024] The Czochralski process is currently the most widely used process for producing crystalline silicon. The Czochralski process mainly includes: high-purity polycrystalline silicon is loaded into a crucible, the crucible is heated by a load high-frequency wave coil or a current heater arranged around the crucible, and the polycrystalline silicon is melted. Then the seed crystal is introduced to obtain a crystalline silicon rod. At present, in order to improve the production efficiency of crystalline silicon, multiple seed crystals are introduced into a single crystal furnace at the same time, and accordingly, the single crystal furnace and the crucible also need to be increased in size.

[0025] At present, multiple seed crystals share one crucible, and due to the increase in size of the crucible, the temperature difference at each position on the liquid surface of the silicon liquid in the crucible becomes larger, and during the rotation of the crucible with increased size, a relatively large vortex of the silicon liquid in the crucible is generated, which affects the quality and yield of the crystalline silicon rod.

[0026] In order to solve the above problems existing in the current single crystal furnace for drawing multiple crystalline silicon rods, the utility model provides a single crystal furnace.

[0027] The specific structure of the single crystal furnace provided by the embodiment of the utility model will be described in detail below.

[0028] Among them, Figure 1 is a cross-sectional structure schematic diagram of the single crystal furnace provided by the embodiment of the utility model; Figure 2 is a three-dimensional structure front view of the relative relationship between the first lifting system, the large crucible and the small crucible in the single crystal furnace provided by the embodiment of the utility model; Figure 3 is a three-dimensional structure top view at a certain angle of the relative relationship between the first lifting system, the large crucible and the small crucible in the single crystal furnace provided by the embodiment of the utility model; Figure 4 is a three-dimensional structure top view at a certain angle of the relative relationship between the second lifting system, the large crucible and the small crucible in the single crystal furnace provided by the embodiment of the utility model; Figure 5 is a three-dimensional structure schematic diagram of the lifting mechanism provided by the embodiment of the utility model; Figure 6 is a top view of the small crucible provided by the embodiment of the utility model; Figure 7 is a schematic diagram of the relative relationship between the load balancing turntable and the connecting rod according to the embodiment of the utility model.

[0029] Specifically, as shown in Figures 1 to 7 The single crystal furnace provided by the embodiment of the utility model can include: a furnace body 10, a lifting system 20, a large crucible 30 and multiple small crucibles 40.

[0030] It is worth noting that the single crystal furnace can also include some structures necessary for direct pulling of crystalline silicon, such as Figure 1The heater 60, the water-cooled heat shield 70 and the support structure 80 are exemplarily shown, wherein the heater 60 is used for heating and keeping the temperature of the silicon liquid in the crucible (the large crucible 30 in the present case); the water-cooled heat shield 70 is used for dissipating the heat of the silicon rod; the support structure 80 is used for providing support for the large crucible 30 and adjusting the position of the large crucible in the single crystal furnace, in addition, the support structure 80 can also drive the large crucible 30 to rotate under the driving of an external driving force.

[0031] Specifically, the structure of the lifting system 20, the large crucible 30 and the plurality of small crucibles 40 is as shown in Figures 1 to 7 .

[0032] As shown in Figure 1 , the lifting system 20 is generally arranged in the sub-chamber of the furnace body 10 to avoid affecting the pulling of the silicon rod in the main chamber.

[0033] Further, as shown in Figures 1 to 4 , the lifting system 20 includes a plurality of seed crystal connecting members 21; each seed crystal connecting member 21 is used for connecting one seed crystal 90; each small crucible 40 is provided with a through hole (not shown in the figure) at the bottom; the plurality of small crucibles 40 are positioned and nested in the large crucible 30 and are in communication with the large crucible 30 through the through holes; the central axis of each small crucible 40 corresponds to one seed crystal connecting member 21, so that the seed crystal connected by the seed crystal connecting member 21 coincides with the central axis of the small crucible 40; the lifting system 20 is coaxial and rotates in the same direction with the large crucible 30.

[0034] Among them, the plurality of seed crystal connecting members 21 and the plurality of small crucibles 40 generally have a one-to-one correspondence, that is, one seed crystal connecting member 21 corresponds to one small crucible 40, and the seed crystal connecting member 21 corresponds to the central axis of the small crucible 40, and different seed crystal connecting members 21 correspond to different small crucibles 40. It is worth noting that during the operation of the single crystal furnace, it is not necessary for all seed crystal connecting members 21 to be connected to seed crystals 90, and the number of seed crystal connecting members 21 connected to seed crystals 90 is not limited.

[0035] Among them, the seed crystal connecting member 21 can be a positioning groove or a clamp, which can connect the seed crystal 90 while cooperating with other structures in the lifting system 20 to position the seed crystal 90 and control the lifting speed of the seed crystal 90 to adapt to the drawing requirements of different growth stages of the silicon rod.

[0036] Among them, the through hole provided at the bottom of the small crucible 40 is in communication with the large crucible 30, which can make the silicon liquid in the large crucible 30 enter the small crucible 40 through the through hole provided at the bottom of the small crucible 40, and different temperatures of the silicon liquid will be further mixed during the process of the silicon liquid entering the small crucible 40 through the through hole, so that the temperature of the silicon liquid entering the small crucible 40 becomes uniform, which is conducive to the pulling of the silicon rod.

[0037] In addition, since the through holes arranged at the bottom of each small crucible 40 are communicated with the large crucible 30, the small crucibles 40 are also communicated with each other, so that the liquid levels of the silicon liquid in the small crucibles 40 are the same, thereby meeting the synchronous growth requirement of the corresponding crystal silicon rods of the small crucibles, and avoiding the inclination of the small crucibles 40 caused by the difference between the liquid levels of the silicon liquid in the small crucibles 40. It can be understood that in the case that no seed crystal 90 is mounted above one small crucible 40, the silicon liquid in the small crucible 40 above which no seed crystal 90 is mounted can flow back to the large crucible 30 through the through holes, so that the liquid levels of the small crucibles 40 are the same.

[0038] It should be noted that the number of the through holes arranged at the bottom of the small crucible 40 can be determined according to requirements, and the number of the through holes arranged at the bottom of the small crucible 40 is not limited herein.

[0039] The large crucible 30 and the small crucible 40 are generally crucibles made of quartz.

[0040] In addition, the structure of the single crystal furnace provided by the utility model can make the center axis of the small crucible 40 correspond to one seed crystal connecting piece 21, so that the center axis of the small crucible 40 corresponding to the seed crystal connecting piece 21 to which the seed crystal is connected coincides, thereby ensuring the normal growth of the crystal silicon rod and improving the drawing quality and yield of the crystal silicon rod.

[0041] The single crystal furnace can simultaneously connect and draw multiple seed crystals through the multiple seed crystal connecting pieces included in the lifting system, so as to draw multiple crystal silicon rods synchronously. The single crystal furnace can provide silicon liquid for drawing the multiple crystal silicon rods through the multiple relatively independent small crucibles nested in the large crucible, thereby solving the problem of large temperature difference of the liquid level of the silicon liquid used for drawing the multiple crystal silicon rods, and blocking the convection generated by the rotation of the large crucible, so as to improve the production efficiency of the crystal silicon rod and improve the quality of the crystal silicon rod.

[0042] Specifically, as shown in Figures 2 to 4 The lifting system 20 can include a load balancing turntable 22 and multiple lifting mechanisms 23, wherein the multiple lifting mechanisms 23 are uniformly distributed in the circumferential direction of the load balancing turntable 22; each lifting mechanism 23 is connected to one seed crystal connecting piece 21; and each lifting mechanism 23 independently controls the lifting and rotation of the seed crystal connected through the seed crystal connecting piece 21.

[0043] The independent control of the seed crystal connected through the seed crystal connecting piece 21 by each lifting mechanism 23 can make the growth speed and growth stage of the crystal silicon rod corresponding to each seed crystal relatively independent, so as to accurately control the lifting speed and position of the seed crystal 90, ensure that each seed crystal 90 maintains a stable position and a proper posture during the drawing process, and adapt to the requirements of different growth stages, thereby further improving the quality and yield of the crystal silicon rod.

[0044] The lifting mechanism 23 is evenly distributed in the circumferential direction of the load balancing turntable 22, which is consistent with the distribution of the small crucibles 40 in the large crucible 30, facilitating the pulling of the crystal silicon rod. On the other hand, the even distribution of the lifting mechanism 23 in the circumferential direction of the load balancing turntable 22 can ensure that the load balancing turntable 22 is balanced as much as possible, thereby prolonging the service life of the load balancing turntable 22.

[0045] The lifting mechanism 23 can be arranged above the load balancing turntable 22, as shown in Figure 2 and Figure 3 The lifting mechanism 23 can also be arranged below the load balancing turntable 22, as shown in Figure 4 The lifting mechanism 23 can include a first rotating shaft 231, a second rotating shaft 232, and a pulling rope 233, regardless of whether the lifting mechanism 23 is arranged above or below the load balancing turntable 22.

[0046] The load balancing turntable 22 can maintain balance by itself, avoiding tilting of the load balancing turntable 22 due to differences in the weight of the crystal silicon rods pulled by the various seeds 90, so as to ensure that the distance between the seeds 90 and the crystal silicon rods pulled by the seeds 90 and the silicon liquid surface is controllable, thereby ensuring that the crystal silicon rods can be normally pulled.

[0047] The relative relationship between the first rotating shaft 231, the second rotating shaft 232, and the pulling rope 233 will be described in detail below, taking the lifting mechanism 23 arranged above the load balancing turntable 22 as an example. Specifically, as shown in Figure 2 , Figure 3 and Figure 5 The lifting mechanism 23 can include a first rotating shaft 231, a second rotating shaft 232, and a pulling rope 233, wherein the first rotating shaft 231 is fixedly connected to the second rotating shaft 232; the first rotating shaft 231 is arranged on the load balancing turntable 22; the axial direction of the first rotating shaft 231 is consistent with the central axis direction of the small crucible 40; the first rotating shaft 231 is provided with a through hole in the axial direction; the axial direction of the second rotating shaft 232 is perpendicular to the axial direction of the first rotating shaft 231; one end of the pulling rope 233 passes through the through hole in the axial direction of the first rotating shaft 231 and is wound around the second rotating shaft 221; the other end of the pulling rope 233 is connected to the seed connecting piece 21; the first rotating shaft 231 rotates around its central axis to drive the second rotating shaft 221 to rotate in the horizontal direction, thereby driving the connected seed to rotate; the second rotating shaft 232 rotates around its central axis to pull or lower the pulling rope 233.

[0048] Further, as shown in Figure 7As shown, the lifting mechanism 23 is arranged above the load-bearing balance turntable 22. The load-bearing balance turntable 22 is provided with a shaft mounting portion 221, through which the first shaft 231 is mounted and the pulling rope 233 is led out.

[0049] In addition, for the structure in which the lifting mechanism 23 is arranged below the load-bearing balance turntable 22, as shown in FIG. Figure 4 As shown, the first rotating shaft 231 and the second rotating shaft 232 are generally enclosed in a housing, so that the housing provides support for the rotation of the first rotating shaft 231.

[0050] The first rotating shaft 231 in the lifting mechanism 23 rotates, driving the second rotating shaft 221 to rotate. The second rotating shaft 221 then drives the seed crystal 90 connected to the seed crystal connector 21 to rotate via the lifting rope 233, achieving self-rotation of the seed crystal 90. Furthermore, the second rotating shaft 221 can synchronously rotate about its own central axis to wrap the lifting rope 233 around the second rotating shaft 221, shortening the vertical length of the lifting rope 233 and thereby lifting the seed crystal 90 upward. The rotation of the second rotating shaft 221 can also lower the lifting rope 233 wrapped around the second rotating shaft 221, thereby lowering the seed crystal 90 downward.

[0051] The central axis of the first rotating shaft 231 coincides with the center line of a small crucible 40. This coincidence allows the center line of the seed crystal 90 to coincide with the center line of the small crucible 40, further improving the quality of the crystalline silicon rod.

[0052] Furthermore, to further improve the quality of the crystalline silicon ingot and ensure that the crystalline silicon ingot and the small crucible 40 remain relatively stationary as much as possible, the centerline of the large crucible 30 passes through the center of the weight-bearing balancing turntable 22. The weight-bearing balancing turntable 22 and the large crucible 30 rotate coaxially and in the same direction. Preferably, the weight-bearing balancing turntable 22 and the large crucible 30 rotate in lockstep. Lockstep generally means that the weight-bearing balancing turntable 22 and the large crucible 30 rotate at the same speed and in the same direction at the same radius within the large crucible 30.

[0053] In the structure of the single crystal furnace provided by this utility model, the multiple small crucibles 40 can be an integrated structure. The multiple small crucibles 40 are relatively fixed, ensuring that the silicon liquid entering the small crucibles 40 maintains a stable liquid level and facilitating the synchronous rotation of the small crucibles 40 and the load-bearing balance turntable 22, thereby improving the quality of the produced crystalline silicon rods.

[0054] Furthermore, regarding the relationship between the small crucible 40 and the large crucible 30:

[0055] like Figure 3 、 Figure 4 and Figure 6As shown, the large crucible 30 is provided with multiple first limiting portions (not shown in the figure); each small crucible 40 is provided with a second limiting portion 41; the second limiting portion 41 cooperates with a first limiting portion to limit the small crucible 40 within the large crucible 30, thereby restricting relative movement of the small crucible 40 and the large crucible 30. By providing multiple first limiting portions on the large crucible 30 and each small crucible 40 with a second limiting portion 41, and by forming multiple small crucibles 40 as an integrated structure, the small crucibles 40 are relatively fixed to the large crucible 30, so that the rotation of the large crucible 30 can drive the synchronous rotation of the small crucibles 40, ensuring that the rotation of the small crucibles 40 is synchronized with the rotation of the load-bearing balance turntable 22, and ensuring that the liquid level of the silicon liquid entering the small crucible 40 remains stable, which helps to improve the quality of the produced crystalline silicon rods.

[0056] Furthermore, a plurality of small crucibles 40 are evenly distributed around the large crucible 30 to further enhance the stability of the large crucible 30 and the small crucibles 40 and to further enhance the stability of the liquid level of the silicon liquid entering the small crucible 40 .

[0057] Specifically, when there are two small crucibles 40 , the center line connecting the two small crucibles 40 coincides with the diameter of the large crucible 30 .

[0058] Furthermore, when the number of small crucibles 40 is greater than or equal to three, the line connecting the centers of every two adjacent small crucibles 40 forms an equilateral figure. For example, when the number of small crucibles 40 is three, the line connecting the centers of every two adjacent small crucibles 40 forms an equilateral triangle. When the number of small crucibles 40 is four, the line connecting the centers of every two adjacent small crucibles 40 forms a square. When the number of small crucibles 40 is five, the line connecting the centers of every two adjacent small crucibles 40 forms a regular pentagon, etc.

[0059] Furthermore, if Figures 1 to 4 and Figure 7 As shown, the single crystal furnace further includes a connecting rod 50, one end of which is rotatably connected to the furnace cover of the furnace body 10; the other end of the connecting rod 50 is fixedly connected to the lifting system 20, so that the connecting rod 50 drives the lifting system 20 to rotate. The connection of the lifting system 20 with the connecting rod 50 facilitates the assembly and disassembly of the lifting system 20.

[0060] like Figure 7 As shown, the lifting system 20 includes a structure in which the load-bearing balancing turntable 22 is fixedly connected to the connecting rod 50 at its center.

[0061] Below Figure 3 The structure of the lifting system 20, the large crucible 30 and the multiple small crucibles 40 of the integrated structure is taken as an example to illustrate the process of preparing single crystal silicon through the Czochralski process in the single crystal furnace provided by the present invention.

[0062] existFigure 3 The load-bearing balance turntable 22 is fixedly connected to a connecting rod 50, which is fixed to the furnace cover of the furnace body 10. The seed crystal connecting pieces 21 connected to the four lifting mechanisms 23 below the load-bearing balance turntable 22 hang the seed crystals 90, and the hung seed crystals 90, the lifting mechanisms 23 and the load-bearing balance turntable 22 are placed in the furnace body 10, wherein each seed crystal 90 corresponds to the center of each small crucible 40. Through an external controller, the load-bearing balance turntable 22 and the large crucible 30 are controlled to rotate coaxially and in the same direction, and the load-bearing balance turntable 22 and the large crucible 30 rotate in step. Further, the external controller independently controls each lifting mechanism 23, so that the first rotating shaft 231 in each lifting mechanism 23 drives the second rotating shaft 232 and the seed crystal 90 to rotate, and the second rotating shaft 232 pulls up or lowers the lifting rope 233, and then lowers the seed crystal 90, so that the seed crystal 90 contacts the silicon liquid surface in the corresponding small crucible 40, starts the necking growth, and forms a thin neck. When the thin neck reaches a predetermined length, it sequentially enters the shoulder growth stage, the equal-diameter growth stage and the finishing stage. Crystalline silicon is grown on the seed crystal 90, and the seed crystal 90 is lifted during the growth of the crystalline silicon.

[0063] The above controller can drive the load-bearing balance turntable 22 and the large crucible 30 through the crystal rotating motor used by the existing single crystal furnace. In addition, each lifting mechanism 23 is controlled to rotate and pull up or lower the lifting rope 233 through an independent motor.

[0064] It is worth noting that the growth rate and stage of each seed crystal 90 can be synchronized or unsynchronized, and no limitation is made herein.

[0065] Through the single crystal furnace, multiple crystalline silicon rods can be pulled at one time, so as to effectively improve the production efficiency of the crystalline silicon rods and improve the quality, consistency and yield of the crystalline silicon rods.

[0066] It is worth noting that after all the crystalline silicon rods are completed, the intelligent control system will guide them to be finished respectively, and then all the completed silicon rods are taken out from the single crystal furnace auxiliary room at one time through an automatic mechanical arm.

[0067] The above steps provide an introduction only to help understand the method, structure and core idea of the present application. For ordinary skilled persons in the technical field, the present application can be improved and modified without departing from the principles of the present application, and these improvements and modifications also belong to the protection scope of the present application.

Claims

1. A single crystal furnace, characterized in that: include: A furnace body (10), a lifting system (20), a large crucible (30), and a plurality of small crucibles (40), wherein: The lifting system (20) is arranged in the sub-chamber of the furnace body (10); The lifting system (20) includes a plurality of seed crystal connecting members (21); Each of the seed crystal connecting pieces (21) is used to connect a seed crystal (90); Each of the small crucibles (40) is provided with a through hole at the bottom; The plurality of small crucibles (40) are positioned and nested in the large crucible (30), and are connected to the large crucible (30) through the through hole; The central axis of each of the small crucibles (40) corresponds to one of the seed crystal connectors (21), so that the seed crystal connected to the seed crystal connector (21) coincides with the central axis of the small crucible (40); The lifting system (20) and the large crucible (30) are coaxial and rotate in the same direction.

2. The single crystal furnace according to claim 1, characterized in that: The lifting system (20) further includes: a load-bearing balance turntable (22) and a plurality of lifting mechanisms (23), wherein: The plurality of lifting mechanisms (23) are evenly distributed in the circumferential direction of the load-bearing balancing turntable (22); Each of the lifting mechanisms (23) is connected to a seed crystal connecting member (21); Each of the lifting mechanisms (23) independently controls the lifting and rotation of the seed crystal connected through the seed crystal connector (21).

3. The single crystal furnace according to claim 2, characterized in that: The lifting mechanism (23) comprises: a first rotating shaft (231), a second rotating shaft (232) and a pulling rope (233), wherein: The first rotating shaft (231) is fixedly connected to the second rotating shaft (232); The first rotating shaft (231) is arranged on the load-bearing balancing rotating disk (22); The axial direction of the first rotating shaft (231) is consistent with the central axis direction of the small crucible (40); The first rotating shaft (231) is provided with a through hole in the axial direction; The axial direction of the second rotating shaft (232) is perpendicular to the axial direction of the first rotating shaft (231); One end of the pulling rope (233) passes through the through hole in the axial direction of the first rotating shaft (231) and is wound around the second rotating shaft (232); The other end of the pulling rope (233) is connected to the seed crystal connector (21); The first rotating shaft (231) rotates around its central axis to drive the second rotating shaft (232) to rotate in the horizontal direction, thereby driving the seed crystal connected thereto to rotate; The second rotating shaft (232) rotates around its central axis and is used to pull or lower the pulling rope (233).

4. The single crystal furnace according to claim 3, characterized in that The central axis of the first rotating shaft (231) coincides with the center line of one of the small crucibles (40).

5. The single crystal furnace according to claim 2, characterized in that: The center line of the large crucible (30) passes through the center of the load-bearing balance turntable (22); The load-bearing balance turntable (22) and the large crucible (30) are coaxial and rotate in the same direction.

6. The single crystal furnace according to claim 1, characterized in that: The plurality of small crucibles (40) are an integrated structure.

7. The single crystal furnace according to any one of claims 1 to 6, characterized in that: The large crucible (30) is provided with a plurality of first limiting portions; Each of the small crucibles (40) is provided with a second limiting portion (41); The second limiting portion (41) cooperates with one of the first limiting portions and is used to limit the position of the small crucible (40) in the large crucible (30) to restrict relative movement between the small crucible (40) and the large crucible (30).

8. The single crystal furnace according to any one of claims 1 to 6, characterized in that: The plurality of small crucibles (40) are evenly distributed in the circumferential direction of the large crucible (30).

9. The single crystal furnace according to claim 8, characterized in that: In the case where there are two small crucibles (40), a line connecting the centers of the two small crucibles (40) coincides with the diameter of the large crucible (30); or, When the number of the small crucibles (40) is greater than or equal to 3, the center line connecting each two adjacent small crucibles (40) encloses an equilateral figure.

10. The single crystal furnace according to any one of claims 1 to 6 and 9, characterized in that: Also includes: Connecting rod (50), wherein One end of the connecting rod (50) is rotatably connected to the furnace cover of the furnace body (10); The other end of the connecting rod (50) is fixedly connected to the lifting system (20), so that the connecting rod (50) drives the lifting system (20) to rotate.

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