Rapid ending method based on continuous Czochralski single crystal (CCz)

Abstract

The invention relates to the technical field of monocrystalline silicon manufacturing, in particular to a rapid ending method based on continuous Czochralski (CCz) single crystal, which comprises the following steps: when the length of a crystal bar reaches a set target length or a specified residual material weight, triggering a rapid ending program; in the first stage, the blanking speed of granular silicon of a granular silicon blanking device is reduced from a normal value to 50%-60% of an initial value at a constant speed, the melt heat consumption is reduced, and the radial temperature difference of the melt is reduced; synchronous speed increasing: after material dropping is started, the pulling speed of the crystal bar is increased to 1.6-1.8 times in a step manner, the diameter of the crystal bar is shrunk, and a solid-liquid interface is kept in a flat state; in the second stage, the blanking speed of the granular silicon blanking device is secondarily reduced to 20%-30% of the initial value. According to the technical scheme, heat is released through the heat capacity of the melt, spontaneous overall synchronous rising of the temperature is achieved through the melt heat capacity conservation principle, temperature lag from the edge to the center is eliminated, the temperature response rate is increased, radial temperature gradient decline is achieved, the tail subfissure extension length is reduced, and the ending time is shortened.

Description

Technical Field

[0001] This invention relates to the field of monocrystalline silicon manufacturing technology, specifically to a rapid finishing method based on continuous Czochralski (CCz) monocrystalline silicon production. Background Technology

[0002] CCZ is an improved Czochralski (CZ) single-crystal silicon growth technology. It replaces the intermittent feeding of the traditional CZ method with a continuous feeding method, enabling a continuous supply of polycrystalline silicon raw materials, such as granular silicon, during a single crystal pulling process. This ensures the continuity of the crystal growth process, thereby improving production efficiency and crystal quality. After the equal-diameter pulling process, the crystal rod needs to be separated from the liquid silicon surface. During this separation, the grown dislocation-free single crystal is subjected to thermal shock. When the thermal stress exceeds the critical stress of silicon, dislocations will be generated, causing the crystal to lose its complete single-crystal structure. Therefore, a special finishing process is required after the equal-diameter pulling process to allow the crystal to gradually separate from the liquid surface, preventing the generated single crystal from developing dislocation defects due to thermal shock.

[0003] However, existing crystal pulling finishing methods typically control the shape of the crystal rod tail by adjusting the pulling speed and power. This often results in problems such as thermal stress concentration due to forced heating and a high rate of microcracks at the crystal rod tail. Furthermore, relying solely on increasing the pulling speed and heating power will delay the temperature response and lengthen the finishing time. Summary of the Invention

[0004] To address the aforementioned technical shortcomings, the purpose of this invention is to provide a rapid culminating method based on continuous Czochralski (CCz) single crystal growth, comprising the following steps:

[0005] S1. When the length of the crystal rod reaches the set target length or the specified weight of the remaining material, the fast finishing procedure is triggered.

[0006] S2, First stage material reduction and temperature control: The particle silicon feeding speed of the particle silicon feeder is uniformly reduced from the normal value to 50%-60% of the initial value, which reduces the heat consumption of the melt and decreases the radial temperature difference of the melt.

[0007] S3. Synchronous speed increase: After the material drop begins, the crystal rod pulling speed is increased by a step to 1.6-1.8 times, the crystal rod diameter shrinks, and the solid-liquid interface maintains a flat shape.

[0008] S4. Second stage deep material reduction: Reduce the feeding speed of the particle silicon feeder to 20%-30% of the initial value for the second time.

[0009] When adjusting the feeding speed of the silicon particle feeder, the output power of the power source needs to be adjusted. Frequent adjustments can damage the power source. To avoid frequent fluctuations in the output power of the power source, the following features are specifically designed: The silicon particle feeder includes a screw feeder. The screw feeder has a feed port and a feeding pipe at both ends of its housing. The feeding pipe extends above the crucible inside the single crystal furnace. A screw shaft is rotatably installed inside the screw feeder. The screw shaft is connected to the working end of the rotary driver via a speed-changing transmission unit. The speed-changing transmission unit includes a fixed rotating shaft and a fixed wheel. The fixed rotating shaft is rotatably installed on a fixed frame and coaxially connected to the screw shaft. The fixed wheel is coaxially installed on the rotating shaft of the rotary driver. A movable conical roller is coaxially installed on the fixed rotating shaft. The fixed wheel and the movable conical roller are connected by a transmission steel belt. The linear driver is used to drive the movable conical roller to move along the axis of the fixed rotating shaft, changing the transmission ratio between the rotary driver and the screw shaft.

[0010] To ensure that the moving conical roller maintains synchronous rotation with the fixed shaft as it moves along the axis, the following features are specifically provided: the moving conical roller has a tapered angle that decreases along the axis; the fixed shaft is a splined shaft; the moving conical roller is slidably mounted on the fixed shaft through a spline groove at the shaft hole; a limit ring is coaxially provided at one end of the moving conical roller; the moving conical roller is rotatably mounted on a mounting base connected to the working end of the linear actuator through the limit ring; and the linear actuator is fixedly mounted on a fixed frame.

[0011] When the moving cone roller moves along the axis of the fixed rotating shaft under the drive of the linear drive, the transmission steel belt may have a tendency to shift laterally. In order to keep the position of the transmission steel belt fixed when the moving cone roller moves, the following features are specifically provided: at least two limiting sleeves are provided on the fixed frame, the limiting sleeves are located above the fixed wheel, and the transmission steel belt rotates inside the limiting sleeves.

[0012] When the moving tapered roller moves along the axis of the fixed rotating shaft, the diameter of the part in contact with the transmission steel belt changes with the taper, which may cause fluctuations in the tension of the transmission steel belt and the wrap angle with the fixed wheel and the moving tapered roller.

[0013] To ensure the tension of the transmission steel belt, the following features are specifically designed: Two limiting tension wheels are provided on the fixed frame. The axis of the limiting tension wheels is parallel to the axis of the fixed rotating shaft. The limiting tension wheels are in contact with the outer side of the transmission steel belt to maintain the wrap angle between the transmission steel belt, the fixed wheel, and the moving conical roller. A slide rail extending horizontally perpendicular to the axis of the fixed rotating shaft is provided on the fixed frame. Two sliding seats are slidably installed within the slide rail. The limiting tension wheels are rotatably mounted on the sliding seats. Each sliding seat has a vertically upward-extending connecting column. A horizontal connecting plate is provided at the bottom of the mounting seat, and inclined adjustment holes are provided on the connecting plate. The connecting columns are inserted into the adjustment holes for limited movement. When the linear actuator drives the mounting seat and the moving conical roller to move along the axis of the fixed rotating shaft, the mounting seat drives the sliding seats to move along the length of the slide rail, changing the distance between the limiting tension wheels.

[0014] Preferably, the inclination direction of the adjustment hole is consistent with the taper reduction direction of the moving cone roller.

[0015] To ensure that the pressure applied to the transmission steel belt by the limit tensioning wheels on both sides is the same, the following feature is specifically designed: the two adjustment holes on both sides of the mounting base are symmetrically arranged in terms of inclination.

[0016] Preferably, the width of the adjusting hole is the same as the diameter of the connecting post.

[0017] To ensure the transmission connection between the fixed rotating shaft and the screw shaft of the screw feeder, the following features are specifically provided: a connecting plug is coaxially provided at one end of the fixed rotating shaft, the cross-sectional shape of the connecting plug is rectangular, and the connecting plug is inserted into a connecting socket provided at one end of the screw shaft that matches the connecting plug.

[0018] The advantages of this invention compared to the prior art are as follows: First, the crystal pulling finishing method in this invention releases heat from the melt's own heat capacity, uses the principle of melt heat capacity conservation to achieve spontaneous overall synchronous temperature rise, eliminates temperature lag from the edge to the center, reconstructs the thermal field distribution mechanism in the finishing stage, thereby improving the temperature response rate, and achieves radial temperature gradient reduction, reducing the length of tail microcrack extension, and shortening the finishing time.

[0019] Secondly, the particle silicon feeder in this invention changes the transmission ratio between the rotary driver and the screw shaft by moving the moving cone roller in the speed transmission unit, rather than directly adjusting the output power of the rotary driver. This effectively avoids damage to the rotating shaft of the rotary driver caused by frequently changing the feeding speed of the screw feeder, extends the service life of the core components, and reduces the equipment failure rate.

[0020] Thirdly, when the movable conical roller in this invention moves along the axis of the fixed rotating shaft, the distance between the two limit tensioning wheels rotatably mounted on the sliding seat is automatically adjusted accordingly, thereby ensuring the tension of the transmission steel belt and the wrap angle with the fixed wheel and the movable conical roller. This maintains a stable transmission connection between the rotary driver and the helical shaft. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a three-dimensional view of a particle silicon feeder in a rapid finishing method based on continuous Czochralski (CCz) single crystal growth.

[0023] Figure 2 This is a top view of a particle silicon feeder in a rapid finishing method based on continuous Czochralski (CCz) single crystal growth.

[0024] Figure 3 for Figure 2 Sectional view at point AA.

[0025] Figure 4 This is a partially enlarged view of a particle silicon feeder in a rapid finishing method based on continuous Czochralski (CCz) single crystal growth.

[0026] Figure 5 for Figure 4 A magnified view of section B.

[0027] Figure 6 This is a front view of a particle silicon feeder in a rapid finishing method based on continuous Czochralski (CCz) single crystal growth.

[0028] Figure 7 for Figure 6 Sectional view at point CC.

[0029] Figure 8 A three-dimensional structural decomposition of a particle silicon feeder in a rapid finishing method based on continuous Czochralski (CCz) single crystal growth. Figure 1 .

[0030] Figure 9 for Figure 8 A magnified view of a portion of point D.

[0031] Figure 10 A three-dimensional structural decomposition of a particle silicon feeder in a rapid finishing method based on continuous Czochralski (CCz) single crystal growth. Figure 2 .

[0032] Figure 11 for Figure 10 A magnified view of a portion at point E.

[0033] Explanation of reference numerals in the attached drawings: 1. Screw feeder; 1a. Feed inlet; 1b. Discharge pipe; 1c. Screw shaft; 1c1. Connecting socket; 2. Rotary drive; 3. Variable speed transmission unit; 3a. Fixed shaft; 3a1. Connecting plug; 3b. Fixed wheel; 3c. Moving conical roller; 3c1. Spline groove; 3c2. Limiting ring; 3d. Transmission steel belt; 3e. Linear drive; 3e1. Mounting base; 3e2. Connecting plate; 3e3. Adjusting hole; 4. Fixed frame; 4a. Limiting sleeve; 4b. Limiting tensioning wheel; 4c. Slide rail; 4c1. Sliding seat; 4c2. Connecting column. Detailed Implementation

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] Reference Figures 1 to 11 :

[0036] A rapid culling method based on continuous Czochralski (CCz) single crystal growth includes the following steps:

[0037] S1. When the length of the crystal rod reaches the set target length or the specified weight of the remaining material, the fast finishing procedure is triggered.

[0038] S2, First stage material reduction and temperature control: The particle silicon feeding speed of the particle silicon feeder is uniformly reduced from the normal value to 50%-60% of the initial value, which reduces the heat consumption of the melt and decreases the radial temperature difference of the melt.

[0039] S3. Synchronous speed increase: After the material drop begins, the crystal rod pulling speed is increased by a step to 1.6-1.8 times, the crystal rod diameter shrinks, and the solid-liquid interface maintains a flat shape.

[0040] S4. Second stage deep material reduction: Reduce the feeding speed of the particle silicon feeder to 20%-30% of the initial value for the second time.

[0041] The finishing method in this application achieves continuous crystal pulling by continuously adding granular silicon to the crucible using a granular silicon feeder with controllable feeding speed. Combined with a gradient monitoring unit composed of an infrared thermal imager, a rapid finishing procedure begins when the ingot length reaches the set target length or a specified remaining weight. This finishing procedure includes dynamic material reduction control in conjunction with the crystal pulling speed. Dynamic material reduction control includes a first-stage material reduction and temperature control, where the granular silicon feeding speed of the feeder is uniformly reduced from a normal value to 50%-60% of the initial value, reducing melt heat consumption and decreasing the radial temperature difference of the melt. After the material reduction begins, the ingot pulling speed is stepped up to 1.6-1.8 times, causing the ingot diameter to shrink and the solid-liquid interface to maintain a flat shape. Subsequently, a second-stage deep material reduction is performed, where the feeding speed of the granular silicon feeder is reduced again to 20%-30% of the initial value. The specific operation logic is shown in the table below.

[0042]

[0043] Current crystal pulling methods typically control the shape of the crystal rod tail by adjusting the pulling speed and power. Relying solely on increasing the pulling speed and heating power results in heat transfer from the external heater to the crucible wall and then to the melt—that is, heat transfer is from the edge to the center. This delays the temperature response and lengthens the finishing time. (See the table below.)

[0044]

[0045] In this embodiment, the heat is released by the melt's own heat capacity. The principle of melt heat capacity conservation is used to achieve a spontaneous, synchronized temperature rise, eliminating temperature lag from the edge to the center, reconstructing the thermal field distribution mechanism in the final stage, thereby improving the temperature response rate. Furthermore, it achieves a radial temperature gradient decrease, reduces the length of microcracks at the tail end, and shortens the final stage time. Specific effects are shown in the table below.

[0046]

[0047] By comparison, this method can be seen to improve the temperature response rate, reduce the radial temperature gradient of the crystal rod, reduce the length of the microcrack extension at the tail, and shorten the termination time.

[0048] When adjusting the feeding speed of the granular silicon feeder, the output power of the power source needs to be adjusted. Frequent adjustments can damage the power source. To avoid frequent fluctuations in the output power of the power source, the following features are specifically designed:

[0049] The granular silicon feeder includes a screw feeder 1. The screw feeder 1 has a feed inlet 1a and a feed pipe 1b at both ends of its housing. The feed pipe 1b extends to the top of the crucible inside the single crystal furnace. A screw shaft 1c is rotatably installed inside the screw feeder 1. The screw shaft 1c is connected to the working end of the rotary driver 2 via a speed transmission unit 3. The speed transmission unit 3 includes a fixed rotating shaft 3a and a fixed wheel 3b. The fixed rotating shaft 3a is rotatably installed on a fixed frame 4 and coaxially connected to the screw shaft 1c. The fixed wheel 3b is coaxially installed on the rotating shaft of the rotary driver 2. A movable conical roller 3c is coaxially installed on the fixed rotating shaft 3a. The fixed wheel 3b and the movable conical roller 3c are connected by a transmission steel belt 3d. A linear driver 3e is used to drive the movable conical roller 3c to move along the axis of the fixed rotating shaft 3a to change the transmission ratio between the rotary driver 2 and the screw shaft 1c.

[0050] When the length of the crystal rod reaches the set target length or the specified weight of remaining material, the rapid finishing procedure is triggered. The adjustment of the granular silicon feeder is achieved by changing the rotational speed of the screw shaft 1c in the screw feeder 1 through the rotary driver 2 and the speed transmission unit 3. The rotary driver 2 can be a servo motor. Under normal conditions, the rotating shaft of the rotary driver 2 drives the fixed wheel 3b to rotate at a constant speed. The fixed wheel 3b drives the transmission steel belt 3d to rotate. The other end of the transmission steel belt 3d is sleeved on the moving conical roller 3c. The moving conical roller 3c is driven by the transmission of the transmission steel belt 3d to rotate the fixed rotating shaft 3a and the screw shaft 1c connected to the fixed rotating shaft 3a. This causes the screw feeder 1 to convey the granular silicon from the feed port 1a to the feed pipe 1b at a constant speed into the single crystal furnace. When entering the first stage of material cooling and temperature control, the linear driver 3e drives the moving conical roller 3c to move along the axis of the fixed rotating shaft 3a, so that the diameter of the contact position between the moving conical roller 3c and the transmission steel belt 3d increases, thereby changing the transmission ratio between the moving conical roller 3c and the fixed wheel 3b. Without changing the rotational speed of the rotary driver 2, the rotational speed of the screw shaft 1c is reduced, thereby realizing the adjustment of the feeding speed. Similarly, when entering the second stage of deep material feeding, the linear drive 3e drives the moving cone roller 3c to move along the axis of the fixed rotating shaft 3a again, further adjusting the transmission ratio, so that the feeding speed of the screw feeder 1 is reduced to 20%-30% of the initial value for the second time. In this embodiment, the transmission ratio between the rotary drive 2 and the screw shaft 1c is changed by the movement of the moving cone roller 3c in the speed transmission unit 3, rather than directly adjusting the output power of the rotary drive 2. This effectively avoids the damage to the rotating shaft of the rotary drive 2 caused by frequent changes in the feeding speed of the screw feeder 1, extends the service life of the core components, and reduces the equipment failure rate.

[0051] To ensure that the fixed rotating shaft 3a and the moving conical roller 3c maintain synchronous rotation when the moving conical roller 3c moves along the axis, the following features are specifically designed:

[0052] The movable tapered roller 3c has a tapered angle that decreases along the axis. The fixed rotating shaft 3a is a spline shaft. The movable tapered roller 3c is slidably mounted on the fixed rotating shaft 3a through the spline groove 3c1 at the shaft hole. A limit ring 3c2 is coaxially provided at one end of the movable tapered roller 3c. The movable tapered roller 3c is rotatably mounted on the mounting base 3e1 connected to the working end of the linear driver 3e through the limit ring 3c2. The linear driver 3e is fixedly mounted on the fixed frame 4.

[0053] like Figure 4 , Figure 9 and Figure 11 As shown, in this embodiment, the fixed rotating shaft 3a is a splined shaft, and the movable tapered roller 3c forms a sliding fit with the fixed rotating shaft 3a through the spline groove 3c1 at the shaft hole. This allows the movable tapered roller 3c to slide freely along the axial direction of the fixed rotating shaft 3a, while ensuring synchronous rotation of both through the spline meshing relationship, thus avoiding transmission failure caused by relative rotation. The linear actuator 3e can be a cylinder, hydraulic cylinder, or electric push rod, etc. The limiting ring 3c2 at one end of the movable tapered roller 3c is rotatably mounted on the mounting base 3e1 connected to the working end of the linear actuator 3e, while the linear actuator 3e is fixed on the fixed frame 4. When the linear actuator 3e drives the mounting base 3e1 to move, the mounting base 3e1 drives the limiting ring 3c2 and the movable tapered roller 3c to move smoothly along the axial direction. Since the limiting ring 3c2 and the mounting base 3e1 are rotatably connected, the rotational movement of the movable tapered roller 3c is not affected by the linear movement. By combining the tapered taper of the movable conical roller 3c along its axis, the contact position between the movable conical roller 3c and the transmission steel belt 3d changes in diameter as the roller moves axially, thereby achieving precise adjustment of the transmission ratio while maintaining synchronous rotation with the fixed rotating shaft 3a.

[0054] When the moving conical roller 3c moves along the axis of the fixed rotating shaft 3a under the drive of the linear actuator 3e, the transmission steel belt 3d may tend to shift laterally. In order to keep the position of the transmission steel belt 3d fixed when the moving conical roller 3c moves, the following features are specifically set:

[0055] At least two limiting sleeves 4a are provided on the fixed frame 4. The limiting sleeves 4a are located above the fixed wheel 3b, and the transmission steel belt 3d rotates inside the limiting sleeves 4a.

[0056] like Figures 4 to 7 As shown, in this embodiment, the transmission steel belt 3d passes through the limiting sleeve 4a fixedly installed on the fixed frame 4. The limiting sleeve 4a restricts the lateral displacement of the transmission steel belt 3d by its fixed spatial position, so that it always stays on the preset transmission path, avoiding deviation due to the change of position of the moving cone roller 3c, ensuring the continuity and accuracy of power transmission during the transmission ratio adjustment process, and providing a reliable guarantee for the precise control of the feeding speed.

[0057] When the moving conical roller 3c moves along the axis of the fixed rotating shaft 3a, the diameter of its contact point with the transmission steel belt 3d changes with the taper, which may cause fluctuations in the tension of the transmission steel belt 3d and the wrap angle with the fixed wheel 3b and the moving conical roller 3c. To ensure the tension of the transmission steel belt 3d, the following features are specifically designed:

[0058] The fixed frame 4 is equipped with two limit tensioning wheels 4b. The axis of the limit tensioning wheel 4b is parallel to the axis of the fixed rotating shaft 3a. The limit tensioning wheel 4b is in contact with the outside of the transmission steel belt 3d to maintain the wrap angle between the transmission steel belt 3d, the fixed wheel 3b and the moving cone roller 3c.

[0059] The fixed frame 4 is provided with a slide rail 4c extending horizontally perpendicular to the axis of the fixed rotating shaft 3a. Two sliding seats 4c1 are slidably installed in the slide rail 4c. The limit tensioning wheel 4b is rotatably installed on the sliding seat 4c1. Each sliding seat 4c1 is provided with a vertically upward extending connecting column 4c2. The bottom of the mounting base 3e1 is provided with a horizontal connecting plate 3e2. The connecting plate 3e2 is provided with an inclined adjustment hole 3e3. The connecting column 4c2 is inserted into the adjustment hole 3e3 for limited movement. When the linear driver 3e drives the mounting base 3e1 and the moving cone roller 3c to move along the axis of the fixed rotating shaft 3a, the mounting base 3e1 drives the sliding seat 4c1 to move along the length direction of the slide rail 4c to change the distance between the limit tensioning wheels 4b.

[0060] like Figures 4 to 10 As shown, in this embodiment, when the linear actuator 3e drives the mounting base 3e1 and the moving conical roller 3c to move along the axis of the fixed rotating shaft 3a, the horizontal connecting plate 3e2 at the bottom of the mounting base 3e1 moves synchronously and its position changes accordingly. Since the connecting post 4c2 on the sliding seat 4c1 is inserted into the tilt adjustment hole 3e3 on the connecting plate 3e2, when the connecting plate 3e2 moves along the axis of the fixed rotating shaft 3a, the tilt adjustment hole 3e3 will generate a horizontal thrust on the connecting post 4c2, thereby driving the sliding seat 4c1 to slide within the slide rail 4c. Therefore, when the moving conical roller 3c moves along the axis of the fixed rotating shaft 3a, the distance between the two limit tensioning wheels 4b rotatably mounted on the sliding seat 4c1 is automatically adjusted accordingly, thereby ensuring the tension of the transmission steel belt 3d and the wrap angle with the fixed wheel 3b and the moving conical roller 3c. This maintains a stable transmission connection between the rotary actuator 2 and the spiral shaft 1c.

[0061] The tilt direction of the adjusting hole 3e3 is consistent with the taper reduction direction of the moving cone roller 3c.

[0062] like Figure 5As shown, in this embodiment, the tilting direction of the adjusting hole 3e3 is consistent with the tapered reduction direction of the moving conical roller 3c. Therefore, when the linear actuator 3e moves the moving conical roller 3c to the side with tapered reduction, the adjusting hole 3e3 on the connecting plate 3e2 generates a horizontal thrust on the connecting column 4c2, which causes the sliding seats 4c1 on both sides to drive the limit tensioning wheels 4b to move closer to each other, thereby keeping the transmission steel belt 3d in contact with the surface of the moving conical roller 3c. Similarly, when the linear actuator 3e moves the moving conical roller 3c to the side with tapered increase, the adjusting hole 3e3 on the connecting plate 3e2 generates a horizontal thrust on the connecting column 4c2, which causes the sliding seats 4c1 on both sides to drive the limit tensioning wheels 4b to move away from each other, thereby preventing the transmission steel strip 3d from breaking due to excessive force.

[0063] To ensure that the pressure applied by the two limit tensioning pulleys 4b to the transmission steel belt 3d is the same, the following features are specifically designed:

[0064] The two adjustment holes 3e3 on both sides of the mounting base 3e1 are symmetrically arranged in terms of tilt direction.

[0065] like Figure 5 As shown, when the mounting base 3e1 moves, the sliding seats 4c1 on both sides are affected by the horizontal thrust generated by the adjustment hole 3e3 on the connecting plate 3e2 on the connecting column 4c2, which drives the limit tensioning wheel 4b to move synchronously in the opposite direction, ensuring that the pressure applied by the limit tensioning wheel 4b on the transmission steel belt 3d is the same.

[0066] The width of the adjusting hole 3e3 is the same as the diameter of the connecting post 4c2.

[0067] Therefore, it can be ensured that when the mounting base 3e1 moves, the sliding base 4c1 can be moved quickly and stably by the horizontal thrust generated by the adjustment hole 3e3 on the connecting plate 3e2 on the connecting column 4c2.

[0068] To ensure the transmission connection between the fixed rotating shaft 3a and the screw shaft 1c of the screw feeder 1, the following features are specifically provided:

[0069] A connector 3a1 is coaxially provided at one end of the fixed rotating shaft 3a. The connector 3a1 has a rectangular cross-sectional shape and is inserted into a connector socket 1c1 at one end of the spiral shaft 1c that matches the connector 3a1.

[0070] like Figure 9As shown, in this embodiment, the connector 3a1 at one end of the fixed rotating shaft 3a and the pre-set connector 1c1 at one end of the spiral shaft 1c form a matching plug-in connection. When the fixed rotating shaft 3a rotates under the drive of the moving conical roller 3c, the rectangular cross-section connector 3a1 directly transmits the torque to the spiral shaft 1c through the rigid fit with the connector 1c1, driving the spiral shaft 1c to rotate synchronously, thereby realizing the conveying of granular silicon. At the same time, this plug-in structure allows for quick disassembly and assembly during installation or maintenance without affecting the transmission synchronization of the two.

[0071] Working Principle: During processing, granular silicon is continuously added to the crucible via a granular silicon feeder with controllable feeding speed to achieve continuous crystal pulling. Combined with a gradient monitoring unit composed of an infrared thermal imager, a rapid finishing process begins when the crystal rod length reaches the set target length or the specified remaining weight. This finishing process includes dynamic material reduction control in conjunction with the crystal pulling speed. Dynamic material reduction control includes a first-stage material reduction and temperature control, where the granular silicon feeding speed of the feeder is uniformly reduced from its normal value to 50%-60% of its initial value, reducing melt heat consumption and decreasing the radial temperature difference of the melt. After the material reduction begins, the crystal rod pulling speed is stepped up to 1.6-1.8 times, the crystal rod diameter shrinks, and the solid-liquid interface remains flat. Subsequently, a second-stage deep material reduction is performed, where the feeding speed of the granular silicon feeder is reduced again to 20%-30% of its initial value.

[0072] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A rapid culminating method based on continuous Czochralski (CCz) single crystal growth, characterized in that, Includes the following steps: S1. When the length of the crystal rod reaches the set target length or the specified weight of the remaining material, the fast finishing procedure is triggered. S2, First stage material reduction and temperature control: The particle silicon feeding speed of the particle silicon feeder is uniformly reduced from the normal value to 50%-60% of the initial value, which reduces the heat consumption of the melt and decreases the radial temperature difference of the melt. S3. Synchronous speed increase: After the material drop begins, the crystal rod pulling speed is increased by a step to 1.6-1.8 times, the crystal rod diameter shrinks, and the solid-liquid interface maintains a flat shape. S4. Second stage deep material reduction: Reduce the feeding speed of the particle silicon feeder to 20%-30% of the initial value for the second time.

2. The rapid culminating method based on continuous Czochralski (CCz) single crystal as described in claim 1, characterized in that, The particle silicon feeder includes a screw feeder (1), with a feed inlet (1a) and a feed pipe (1b) at both ends of the housing of the screw feeder (1). The feed pipe (1b) extends to the top of the crucible inside the single crystal furnace. A screw shaft (1c) is rotatably installed inside the screw feeder (1). The screw shaft (1c) is connected to the working end of the rotary driver (2) via a speed transmission unit (3). The speed transmission unit (3) includes a fixed rotating shaft (3a) and a fixed wheel (3b). 3a) Rotatably mounted on the fixed frame (4) and coaxially connected to the helical shaft (1c), the fixed wheel (3b) is coaxially mounted on the rotating shaft of the rotary driver (2), the movable cone roller (3c) is coaxially mounted on the fixed rotating shaft (3a), the fixed wheel (3b) and the movable cone roller (3c) are connected by transmission steel belt (3d), and the linear driver (3e) is used to drive the movable cone roller (3c) to move along the axis of the fixed rotating shaft (3a) to change the transmission ratio between the rotary driver (2) and the helical shaft (1c).

3. The rapid culminating method based on continuous Czochralski (CCz) single crystal as described in claim 2, characterized in that, The movable conical roller (3c) has a tapered shape that decreases along the axis. The fixed rotating shaft (3a) is a spline shaft. The movable conical roller (3c) is slidably mounted on the fixed rotating shaft (3a) through the spline groove (3c1) at the shaft hole. A limit ring (3c2) is coaxially provided at one end of the movable conical roller (3c). The movable conical roller (3c) is rotatably mounted on the mounting base (3e1) connected to the working end of the linear driver (3e) through the limit ring (3c2). The linear driver (3e) is fixedly mounted on the fixed frame (4).

4. The rapid culminating method based on continuous Czochralski (CCz) single crystal as described in claim 2, characterized in that, At least two limiting sleeves (4a) are provided on the fixed frame (4). The limiting sleeves (4a) are located above the fixed wheel (3b), and the transmission steel belt (3d) rotates inside the limiting sleeves (4a).

5. The rapid culminating method based on continuous Czochralski (CCz) single crystal as described in claim 2, characterized in that, The fixed frame (4) is provided with two limiting tension wheels (4b). The axis of the limiting tension wheel (4b) is parallel to the axis of the fixed rotating shaft (3a). The limiting tension wheel (4b) fits against the outside of the transmission steel belt (3d) to maintain the wrap angle between the transmission steel belt (3d), the fixed wheel (3b) and the moving cone roller (3c).

6. The rapid culminating method based on continuous Czochralski (CCz) single crystal as described in claim 5, characterized in that, The fixed frame (4) is provided with a slide rail (4c) extending horizontally perpendicular to the axis of the fixed rotating shaft (3a). Two sliding seats (4c1) are slidably installed in the slide rail (4c). The limiting tension wheel (4b) is rotatably installed on the sliding seat (4c1). Each sliding seat (4c1) is provided with a vertically upward extending connecting column (4c2). The bottom of the mounting seat (3e1) is provided with a horizontal connecting plate (3e2). The connecting plate (3e2) is provided with an inclined adjustment hole (3e3). The connecting column (4c2) is inserted into the adjustment hole (3e3) for limited movement. When the linear driver (3e) drives the mounting seat (3e1) and the moving cone roller (3c) to move along the axis of the fixed rotating shaft (3a), the mounting seat (3e1) drives the sliding seat (4c1) to move along the length direction of the slide rail (4c) to change the distance between the limiting tension wheels (4b).

7. The rapid culminating method based on continuous Czochralski (CCz) single crystal as described in claim 6, characterized in that, The tilting direction of the adjustment hole (3e3) is consistent with the taper reduction direction of the moving cone roller (3c).

8. The rapid culminating method based on continuous Czochralski (CCz) single crystal as described in claim 6, characterized in that, The two adjustment holes (3e3) on both sides of the mounting base (3e1) are symmetrically arranged in terms of tilt direction.

9. A rapid culminating method based on continuous Czochralski (CCz) single crystal as described in claim 6, characterized in that, The width of the adjustment hole (3e3) is the same as the diameter of the connecting post (4c2).

10. A rapid culminating method based on continuous Czochralski (CCz) single crystal as described in claim 6, characterized in that, One end of the fixed rotating shaft (3a) is coaxially provided with a connecting plug (3a1). The cross-sectional shape of the connecting plug (3a1) is rectangular. The connecting plug (3a1) is inserted into a connecting socket (1c1) that matches the connecting plug (3a1) at one end of the spiral shaft (1c).

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