Crystal pulling system and design method and control method thereof

Abstract

The invention discloses a crystal pulling system and a design method and a control method thereof. The crystal pulling system comprises: a crucible assembly comprising an outer crucible and an inner crucible; the feeding assembly comprises a feeding pipe and a first air supply device, the lower end of the feeding pipe extends to the position between the outer crucible and the inner crucible, and the first air supply device communicates with the feeding pipe so as to supply feeding airflow V1 to the feeding pipe; the second air supply device is located above the crucible assembly and supplies cooling air flow V2 downwards; the guide cylinder is positioned between the second gas supply device and the crucible assembly and is provided with a bottom end part extending to the inner side of the inner crucible; and the blocking cylinder surrounds between the feeding pipe and the inner crucible, is connected to the guide cylinder and extends downwards from the guide cylinder, the lower end of the blocking cylinder is higher than the bottom end part of the guide cylinder, and the height difference value H < = H1 = 100V < 22 > + 30V < 2 > + 100V < 12 >-200V < 1 >-200. Thus, stable air flow from inside to outside is formed at the lower end of the blocking cylinder, and the quality of monocrystalline silicon is guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of single crystal silicon production, and in particular to a crystal pulling system and a design method and a control method thereof. Background Art

[0002] With the widespread application of single crystal silicon, the preparation process of single crystal silicon has gradually developed, from multiple crystal pulling technology (Recharged Czocharlski, referred to as RCZ) to continuous Czocharlski single crystal technology (Continuous Czocharlski, referred to as CCZ).

[0003] At present, when growing single crystal silicon by CCZ method, solid raw materials are first continuously added to the quartz crucible of the crystal pulling system for melting to form silicon melt, and then the seed crystal is lowered into the melt and slowly rises from the melt, so that the melt solidifies on the seed crystal and grows a single crystal silicon rod. During this period, the following technical difficulties are faced: the added solid raw materials may be suspended in the air due to dust, mutual collision and other reasons. These solid raw materials suspended in the air can be generally defined as "dust"; during the growth of single crystal silicon, these dusts are very likely to move toward the growing crystal rod, thereby contacting the growing crystal rod, and then causing defects and dislocations in the grown single crystal silicon.

[0004] Therefore, in the preparation of single crystal silicon, how to prevent dust from contacting the growing crystal rod is of great significance to improving the quality of single crystal silicon. Summary of the invention

[0005] The object of the present invention is to provide a crystal pulling system and a design method and a control method thereof, so as to solve the problem of defects and dislocations in single crystal silicon caused by dust.

[0006] To achieve the above-mentioned purpose, an embodiment of the present invention provides a crystal pulling system. The crystal pulling system comprises:

[0007] A crucible assembly, comprising an outer crucible and an inner crucible, wherein the outer crucible surrounds the outside of the inner crucible, and the interior of the inner crucible forms a crystal growth zone;

[0008] A feeding assembly, comprising a feeding pipe and a first gas supply device, wherein the lower end of the feeding pipe extends between the outer crucible and the inner crucible, and the first gas supply device is connected to the feeding pipe to supply a feeding gas flow to the feeding pipe;

[0009] A second gas supply device, which is located above the crucible assembly and supplies a cooling gas flow downward;

[0010] a guide tube, which is located between the second gas supply device and the crucible assembly and has a bottom end portion extending to the inner side of the inner crucible;

[0011] The crystal pulling system further includes a barrier tube; the barrier tube surrounds the feeding tube and the inner crucible, is connected to the guide tube and extends downward from the guide tube, and the lower end of the barrier tube is higher than the bottom end of the guide tube and the height difference H≤H1, H1=100V2 2 +30V2+100V1 2 -200V1-200;

[0012] Among them, V1 is the preset value of the flow rate of the feeding airflow, the unit is m / s; V2 is the preset value of the flow rate of the cooling airflow, the unit is m / s; H and H1 are in mm.

[0013] As a further improvement of one embodiment, a height difference H between the lower end of the barrier tube and the bottom end of the guide tube also satisfies H≥H1-50 and / or H≤H1-10.

[0014] As a further improvement of one embodiment, the inner wall of the outer crucible and the outer wall of the inner crucible jointly define a melting zone, the feeding pipe and the barrier tube both extend downward toward the melting zone, and the melting zone and the crystal growth zone are connected through an opening at the lower part of the inner crucible;

[0015] Alternatively, the crucible assembly also includes a middle crucible, which is located between the inner crucible and the outer crucible, the inner wall of the outer crucible and the outer wall of the middle crucible jointly define a melting zone, the feeding tube extends downward toward the melting zone, the inner wall of the middle crucible and the outer wall of the inner crucible jointly define a transition zone, the barrier tube is located between the middle crucible and the inner crucible and extends downward toward the transition zone, and the melting zone and the crystal growth zone are connected via the transition zone.

[0016] As a further improvement of one embodiment, the lower end of the barrier tube is lower than at least one of the upper edge of the inner crucible and the upper edge of the middle crucible.

[0017] As a further improvement of an embodiment, the second gas supply device includes a second driver and a gas supply channel, the second driver is connected to the gas supply channel, and the gas supply channel is located above the center of the inner crucible and extends vertically;

[0018] The crystal pulling system further includes a control device, which collects a preset flow rate value V1 of the feed air flow and a preset flow rate value V2 of the cooling air flow, and controls the operation of the first air supply device and the second air supply device.

[0019] To achieve the above-mentioned purpose, an embodiment of the present invention provides a design method of a crystal pulling system. The crystal pulling system comprises:

[0020] A crucible assembly comprising an outer crucible and an inner crucible, wherein the outer crucible surrounds the outer portion of the inner crucible;

[0021] a feeding tube, the lower end of which extends between the outer crucible and the inner crucible;

[0022] A guide tube, which is located above the crucible assembly and extends downward to the inner side of the inner crucible;

[0023] The design method comprises the following steps:

[0024] Collecting a preset flow rate value V1 of the feeding airflow and a preset flow rate value V2 of the cooling airflow in the feeding pipe;

[0025] The barrier tube is designed to be located between the feeding tube and the inner crucible and connected to the guide tube at the top so that the lower end of the barrier tube is higher than the highest liquid level line of the melt in the crucible assembly.

[0026] h≤h1=100V2 2 +30V2+100V1 2 -200V1-190;

[0027] The unit of V1 and V2 is m / s; the unit of h and h1 is mm.

[0028] As a further improvement of one embodiment, the distance h also satisfies: h≤h1-5, and / or, h≥h1-50.

[0029] To achieve the above-mentioned object of the invention, an embodiment of the present invention provides a control method of a crystal pulling system. The crystal pulling system comprises:

[0030] A crucible assembly comprising an outer crucible and an inner crucible, wherein the outer crucible surrounds the outer portion of the inner crucible;

[0031] A feeding assembly, comprising a feeding pipe and a first gas supply device, wherein the lower end of the feeding pipe extends between the outer crucible and the inner crucible, and the first gas supply device is connected to the feeding pipe to supply a feeding gas flow to the feeding pipe;

[0032] A second gas supply device, which is located above the crucible assembly and supplies a cooling gas flow downward;

[0033] a guide tube, which is located between the second gas supply device and the crucible assembly and has a bottom end portion extending to the inner side of the inner crucible;

[0034] The crystal pulling system further includes a barrier tube, which is located between the feeding tube and the inner crucible and is connected to the guide tube and extends downward from the guide tube;

[0035] The control method comprises:

[0036] The flow rates of the feed airflow of the first air supply device and the cooling airflow of the second air supply device are controlled so that an airflow from inside to outside is formed at the lower end of the barrier cylinder.

[0037] As a further improvement of an embodiment, the control method further includes: collecting a distance H by which the lower end of the barrier tube is higher than the bottom end of the guide tube;

[0038] The “controlling the flow rates of the feed airflow of the first air supply device and the cooling airflow of the second air supply device so that an airflow from inside to outside is formed at the lower end of the barrier cylinder” is: controlling the flow rate value v1 of the feed airflow and the flow rate value v2 of the cooling airflow to satisfy v2 2 +0.3v2+v1 2 -2v1-2-0.01H≥k; where k≥0 and is a constant, the units of v1 and v2 are m / s, and the unit of H is mm.

[0039] As a further improvement of an embodiment, the control method further includes: collecting a distance h by which the lower end of the barrier cylinder is higher than a maximum liquid level line of the melt in the crucible assembly;

[0040] The “controlling the flow rates of the feed airflow of the first air supply device and the cooling airflow of the second air supply device so that an airflow from inside to outside is formed at the lower end of the barrier cylinder” is: controlling the flow rate value v1 of the feed airflow and the flow rate value v2 of the cooling airflow to satisfy v2 2 +0.3v2+v1 2 -2v1-2-0.01(h-10)≥k; where k≥0 and is a constant, the unit of v1 and v2 is m / s, and the unit of h is mm.

[0041] Compared with the prior art, the beneficial effects of one embodiment are:

[0042] On the one hand, by setting up the barrier cylinder, the inward chaotic movement of dust can be greatly blocked;

[0043] On the other hand, a stable airflow from inside to outside can be formed at the lower end of the barrier cylinder, thereby forming an airflow from the growing single crystal silicon rod through the lower end of the barrier cylinder to the feeding pipe as a whole, thereby not only preventing the dust at the feeding pipe from moving inward to the single crystal silicon rod, but also promoting the transfer of foreign matter around the single crystal silicon rod to the feeding pipe, greatly improving the cleanliness of the air around the growing single crystal silicon rod, and ensuring the quality of the single crystal silicon;

[0044] On the other hand, the technical solution of the present application is highly versatile and can provide effective response solutions for different production conditions in the preparation of different single crystal silicon. It can ensure the quality stability of different batches of single crystal silicon and has important guiding significance in actual production. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1a is a schematic structural diagram of a crystal pulling system according to an embodiment of the present invention;

[0046] Figure 1b yes Figure 1a A partial enlarged view of the middle A area;

[0047] Figure 2a is a schematic structural diagram of a crystal pulling system according to a modified embodiment of the present invention;

[0048] Figure 2b yes Figure 2a A partial enlarged view of the middle B area;

[0049] Figure 3 is a flow chart of a method for designing a crystal pulling system according to an embodiment of the present invention;

[0050] Figure 4 is a flow chart of a control method of a crystal pulling system according to an embodiment of the present invention;

[0051] Figure 5 It is a flow chart of a control method of a crystal pulling system according to another embodiment of the present invention. DETAILED DESCRIPTION

[0052] The technical solution of the present invention is further introduced below in conjunction with the accompanying drawings and specific implementation methods.

[0053] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0054] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0055] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or a communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0056] Ginseng Figure 1a and Figure 1b An embodiment of the present invention provides a crystal pulling system 100 for the continuous production of straight-pulled single crystal silicon, and can solve the technical problem of dust contacting the growing crystal rod faced in the prior art, and can greatly reduce the defects and dislocations of the single crystal silicon and improve the product quality.

[0057] In general, the crystal pulling system 100 includes a crucible assembly 10 , a material feeding assembly 20 , a second gas supply device 30 , a guide tube 40 , and a barrier tube 50 .

[0058] The crucible assembly 10 includes an outer crucible 11 and an inner crucible 12 .

[0059] The outer crucible 11 surrounds the outer portion of the inner crucible 12 , that is, the inner crucible 12 is located inside the outer crucible 11 , and the inner diameter of the outer crucible 11 is greater than the outer diameter of the inner crucible 12 .

[0060] A crystal growth zone 102 is formed inside the inner crucible 12, and the crystal growth zone 102 is also the region where the single crystal silicon rod is grown. That is, when preparing single crystal silicon, the seed crystal enters the melt in the inner crucible 12 and slowly rises from the melt, so that the melt solidifies on the seed crystal and grows a single crystal silicon rod.

[0061] The feeding assembly 20 includes a feeding pipe 21 and a first air supply device 22 .

[0062] The lower end of the feeding tube 21 extends between the outer crucible 11 and the inner crucible 12, so that the solid raw material is added to the crucible assembly 10 through the feeding tube 21. Specifically, the solid raw material is added between the outer crucible 11 and the inner crucible 12 through the feeding tube 21. In this way, in the production of single crystal silicon, after the solid raw material added between the outer crucible 11 and the inner crucible 12 is melted, the melt eventually flows into the inner crucible 12, and the growth of the single crystal silicon rod is achieved in the inner crucible 12.

[0063] The first gas supply device 22 is connected to the feeding pipe 21 to supply a feeding gas flow to the feeding pipe 21. It can be understood that the feeding gas flow can flow downward along the feeding pipe 21, thereby driving the solid material in the feeding pipe 21 to be added into the crucible assembly 10.

[0064] The second gas supply device 30 is located above the crucible assembly 10 and supplies a cooling gas flow downward.

[0065] The guide tube 40 is located between the second gas supply device 30 and the crucible assembly 10, that is, located above the crucible assembly 10 and below the second gas supply device 30; and the guide tube 40 has a bottom end portion 41 extending to the inner side of the inner crucible 12. In this way, through the arrangement of the second gas supply device 30 and the guide tube 40, the cooling airflow provided by the second gas supply device 30 can flow downward into the inner crucible 12 under the guidance of the guide tube 40, so that, on the one hand, a relatively low temperature area is formed on the surface of the crystal growth zone 102 of the inner crucible 12, providing growth power for crystal growth; on the other hand, the cooling airflow can enter the interior of the thermal field, effectively cool the crystal rod, and accelerate the release of latent heat of crystallization.

[0066] As described above, in the production of single crystal silicon, when the solid raw materials of the crystal pulling system 100 are fed to the outside of the inner crucible 12 through the feeding pipe 21, if the generated dust moves inward to the inside of the inner crucible 12, it will cause defects and dislocations in the growing single crystal silicon rod.

[0067] In order to solve this technical problem, in the present application, the barrier tube 50 surrounds between the feeding tube 21 and the inner crucible 12, that is, the barrier tube 50 surrounds the inner side of the feeding tube 21 and the outer side of the inner crucible 12. In addition, the upper end of the barrier tube 50 is connected to the guide tube 40, and it extends downward from the guide tube 40. In this way, the barrier tube 50 is intended to constitute a barrier between the feeding tube 21 and the inner crucible 12, so that even if the solid raw material flowing out of the feeding tube 21 becomes dust floating in the air, it will first hit the barrier tube 50 when moving inward, and then it is difficult to move into the inner crucible 12, thereby reducing the probability of dust contacting the growing single crystal silicon rod.

[0068] Based on the research findings, the production requirements and production conditions for any two different preparations of single crystal silicon are different. Sometimes the barrier tube 50 can play a role in blocking the chaotic inward movement of dust to a certain extent, but the reduction effect is not satisfactory; in addition, sometimes the barrier tube 50 is not conducive to the cleanliness around the growing single crystal silicon rod. For example, an airflow flowing inward in a curve from the feeding pipe 21 will be formed, causing the dust to smoothly reach the growing single crystal silicon rod along this airflow.

[0069] In the present application, the lower end of the barrier tube 50 is higher than the bottom end 41 of the guide tube 40 and the height difference H≤H1, H1=100V2 2 +30V2+100V1 2 -200V1-200.

[0070] The units of H and H1 are mm.

[0071] Furthermore, V1 is the preset value of the flow rate of the feeding airflow, that is, the preset value of the airflow rate supplied by the first air supply device 22, and the unit is m / s; V2 is the preset value of the flow rate of the cooling airflow, that is, the preset value of the airflow rate supplied by the second air supply device 30, and the unit is m / s.

[0072] Thus, compared with the prior art, in one embodiment of the present invention, the lower end height of the barrier cylinder 50 is associated with the height of the bottom end portion 41 of the guide cylinder 40, the preset flow rate value of the cooling airflow, and the preset flow rate value of the feed airflow.

[0073] On the one hand, the barrier cylinder 50 can greatly block the chaotic inward movement of dust;

[0074] On the other hand, a stable airflow from inside to outside can be formed at the lower end of the barrier cylinder 50, thereby forming an airflow from the growing single crystal silicon rod through the lower end of the barrier cylinder 50 to the feeding pipe 21 as a whole, thereby not only preventing the dust at the feeding pipe 21 from moving inward to the single crystal silicon rod, but also promoting the transfer of foreign matter around the single crystal silicon rod to the feeding pipe 21, greatly improving the cleanliness of the air around the growing single crystal silicon rod, and ensuring the quality of the single crystal silicon;

[0075] On the other hand, the technical solution of the present application is highly versatile and can provide effective response solutions for different production conditions in the preparation of different single crystal silicon. It can ensure the quality stability of different batches of single crystal silicon and has important guiding significance in actual production.

[0076] Preferably, the height difference H can further satisfy H≤H1-5, preferably H≤H1-10. It has been found through research that by controlling H below H1-5, even in actual production, the actual flow rate of the feed airflow changes appropriately around the preset flow rate value V1, or the actual flow rate of the cooling airflow changes appropriately around the preset flow rate value V2, it can still ensure that the lower end of the barrier cylinder 50 forms a stable airflow from the inside to the outside, thereby preventing the dust at the feeding pipe 21 from moving inward to the single crystal silicon rod, and promoting the transfer of foreign matter around the single crystal silicon rod to the feeding pipe 21, greatly improving the cleanliness of the air around the growing single crystal silicon rod, and ensuring the quality of the single crystal silicon; and in actual production, the flow rate of the cooling airflow and the flow rate of the feed airflow are fine-tuned compared to the preset value according to the production conditions, which is very common. Therefore, this preferred design can cope with actual production while ensuring the production quality of single crystal silicon, promote the smooth progress of actual production, and is of great value.

[0077] Furthermore, the height difference H can further satisfy H≥H1-50, for example, H is controlled between H1-50 and H1, or between H1-50 and H1-5, more preferably between H1-30 and H1-5, or between H1-30 and H1-10. In this way, not only can a stable airflow from inside to outside be formed at the lower end of the barrier cylinder 50 to solve the problem of dust contacting the growing single crystal silicon rod, but also the stability of the airflow can be ensured to avoid strong and rapid turbulence, thereby facilitating the stability of the thermal field and the liquid surface stability of the melt, and ensuring the success rate of crystal pulling and production efficiency.

[0078] In one embodiment, the barrier tube 50 and the guide tube 40 may be integrally formed, or may be separately formed and fixedly assembled together.

[0079] The inner side surface of the guide tube 40 is in an inverted cone shape, that is, the upper diameter is large and the lower diameter is small, so as to guide the cooling air flow supplied by the second gas supply device 30 downward to the middle of the inner crucible 12 .

[0080] In one embodiment, the crystal pulling system 100 further includes a furnace body 60 and a support base 70 .

[0081] The support seat 70 , the crucible assembly 10 , the guide tube 40 and the barrier tube 50 are all arranged in the furnace body 60 .

[0082] The support seat 70 is connected to the furnace body 60 rotatably around the central axis. The crucible assembly 10 can be fixedly supported on the support seat 70 and can rotate around the central axis together with the support seat 70; the guide tube 40 and the barrier tube 50 can be fixedly connected to the furnace body 60 and suspended above the crucible assembly 10.

[0083] Further, the second gas supply device 30 includes a second driver 32 (such as a fan or an air pump) and a gas supply channel 31, the second driver 32 is connected to the gas supply channel 31, and the gas supply channel 31 is located above the center of the inner crucible 12 and extends vertically. In this way, the cooling airflow is supplied to the gas supply channel 31 through the second driver 32, so that the cooling airflow flows downward along the gas supply channel 31 and flows into the inner crucible 12 under the guidance of the guide tube 40.

[0084] In one embodiment, the air supply channel 31 may be fixedly connected to the top of the furnace body 60 , and the cooling air flow may enter the furnace body 60 from the air supply channel 31 .

[0085] In one embodiment, both the cooling gas stream and the feed gas stream are inert gas, such as argon.

[0086] Furthermore, the crystal pulling system 100 further includes an exhaust device, which is connected to the crucible assembly 10 so that the airflow at the upper part of the crucible assembly 10 can flow out of the outer crucible 11 and be discharged through the exhaust device. Specifically, for example, the exhaust device may include an exhaust channel and a driver (such as a fan, an air pump, etc.), and the driver is used to drive the airflow flowing out of the outer crucible 11 into the exhaust channel, and then can be discharged outside the furnace body 60.

[0087] Furthermore, the crystal pulling system 100 further includes a control device.

[0088] The control device collects a preset flow rate value V1 of the feed air flow and a preset flow rate value V2 of the cooling air flow, and electrically connects the first air supply device 22 and the second air supply device 30 to control the operation of the first air supply device 22 and the second air supply device 30, such as controlling the start and stop of the first air supply device 22 and the second air supply device 30, the flow rate of the feed air flow and the flow rate of the cooling air flow.

[0089] In addition, the control device collects a preset value P of the air pressure in the furnace body 60 and is electrically connected to the driver to control the operation of the driver so that the air pressure in the furnace body 60 remains stable, for example, maintained at about the preset value P of the air pressure.

[0090] The control device may specifically include a collector, a memory and a processor.

[0091] The collector can specifically be an input device such as a keyboard, touch screen, touchpad, mouse, camera, microphone, etc., for collecting the preset flow rate value V1 of the feeding airflow, the preset flow rate value V2 of the cooling airflow, and the preset air pressure value P. It can be understood that V1 and V2 can be determined according to production needs.

[0092] The memory may be used to store various collected data, including but not limited to the preset flow rate value V1 of the feed gas flow, the preset flow rate value V2 of the cooling gas flow, and the preset air pressure value P, and may store a program for the crystal pulling system 100 to operate, such as a control method for the crystal pulling system 100. The memory may be specifically configured as a read-only memory (ROM), a random access memory (RAM), and the like.

[0093] The processor can read data from the memory and execute various programs in the memory. The processor can specifically be a central processing unit, a graphics processing unit, etc.

[0094] In other words, the control device can be integrated into one electronic device or distributed in different electronic devices. For example, the control device can be integrated into industrial computers, PLCs and other devices for implementation, but is not limited thereto.

[0095] Furthermore, in one embodiment, the crucible assembly 10 is configured as a two-layer structure.

[0096] For example, the inner wall of the outer crucible 11 and the outer wall of the inner crucible 12 jointly define the melting zone 101 , the feeding tube 21 and the barrier tube 50 both extend downward toward the melting zone 101 , and the melting zone 101 and the crystal growth zone 102 are connected through the opening 120 at the lower part of the inner crucible 12 .

[0097] Preferably, the lower end of the barrier tube 50 is lower than the upper edge of the inner crucible 12 .

[0098] Ginseng Figure 2a and Figure 2b In a variation of the embodiment, the crucible assembly 10 is configured as a three-layer structure.

[0099] For example, the crucible assembly 10 further includes a middle crucible 13, which is located between the inner crucible 12 and the outer crucible 11. The inner wall of the outer crucible 11 and the outer wall of the middle crucible 13 together define a melting zone 101, and the feeding pipe 21 extends downward toward the melting zone 101; the inner wall of the middle crucible 13 and the outer wall of the inner crucible 12 together define a transition zone 103, and the barrier tube 50 is located between the middle crucible 13 and the inner crucible 12 and extends downward toward the transition zone 103; the melting zone 101 and the crystal growth zone 102 are connected via the transition zone 103.

[0100] Preferably, the lower end of the barrier tube 50 is lower than the upper edge of the middle crucible 13 and / or lower than the upper edge of the inner crucible 12 .

[0101] certainly, Figure 1a and Figure 2b Each of the figures illustrates an optional specific structure of the crucible assembly 10 , but the structure of the crucible assembly 10 is not limited thereto, and can also be implemented with other feasible structures in the art.

[0102] Next, an embodiment of the present invention further provides a design method of a crystal pulling system 100, which can be combined with Figure 1a and Figure 2b The structure of the crystal pulling system 100 is shown to be understood.

[0103] The design method comprises the following steps:

[0104] Collect the preset flow rate value V1 of the feeding airflow and the preset flow rate value V2 of the cooling airflow in the feeding pipe 21; wherein the unit of V1 and V2 is m / s;

[0105] The barrier tube 50 is designed to be located between the feeding tube 21 and the inner crucible 12 and connected to the guide tube 40 at the top, so that the lower end of the barrier tube 50 is higher than the bottom end 41 of the guide tube 40 by a distance

[0106] H≤H1=100V2 2 +30V2+100V1 2 -200V1-200; wherein the distance H is also the height difference H mentioned above, and the units of H and H1 are mm.

[0107] Thus, compared with the prior art, in a design method of one embodiment of the present invention, the height of the lower end of the barrier cylinder 50 is associated with the height of the bottom end portion 41 of the guide cylinder 40, the preset flow rate of the cooling airflow, and the preset flow rate of the feeding airflow. On the one hand, the barrier cylinder 50 can greatly block the chaotic inward movement of dust; on the other hand, a stable airflow from the inside to the outside can be formed at the lower end of the barrier cylinder 50, which greatly improves the cleanliness of the air around the growing single crystal silicon rod and ensures the quality of the single crystal silicon; on the other hand, the technical solution of the present application is highly versatile, and can provide effective response plans for different production conditions in the preparation of different single crystal silicon, and can ensure the quality stability of different batches of single crystal silicon.

[0108] Preferably, H may further satisfy H≤H1-5, preferably H≤H1-10.

[0109] Preferably, H may further satisfy H≥H1-50, for example, H is controlled between H1-50 and H1, or between H1-50 and H1-5, more preferably between H1-30 and H1-5, or between H1-30 and H1-10.

[0110] Next, from another perspective, Figure 3 , the design method of one embodiment includes:

[0111] Collect the preset flow rate value V1 of the feeding airflow and the preset flow rate value V2 of the cooling airflow in the feeding pipe 21; wherein the unit of V1 and V2 is m / s;

[0112] The barrier tube 50 is designed to be located between the feeding tube 21 and the inner crucible 12 and connected to the guide tube 40 at the top, so that the lower end of the barrier tube 50 is higher than the highest liquid level of the melt of the crucible assembly 10 by a distance h≤h1=100V2 2 +30V2+100V1 2 -200V1-190; where the units of h and h1 are mm.

[0113] Thus, compared with the prior art, in one embodiment of the present invention, the lower end height of the barrier cylinder 50 is designed in association with the highest liquid level of the melt of the crucible assembly 10, the preset flow rate of the cooling air flow, and the preset flow rate of the feed air flow:

[0114] On the one hand, the barrier cylinder 50 can greatly block the chaotic inward movement of dust;

[0115] On the other hand, a stable airflow from inside to outside can be formed at the lower end of the barrier cylinder 50, thereby forming an airflow from the growing single crystal silicon rod through the lower end of the barrier cylinder 50 to the feeding pipe 21 as a whole, thereby not only preventing the dust at the feeding pipe 21 from moving inward to the single crystal silicon rod, but also promoting the transfer of foreign matter around the single crystal silicon rod to the feeding pipe 21, greatly improving the cleanliness of the air around the growing single crystal silicon rod, and ensuring the quality of the single crystal silicon;

[0116] On the other hand, the technical solution of the present application is highly versatile and can provide effective response solutions for different production conditions in the preparation of different single crystal silicon. It can ensure the quality stability of different batches of single crystal silicon and has important guiding significance in actual production.

[0117] The highest liquid level of the melt in the crucible assembly 10 is usually located below the bottom end 41 of the guide tube 40 , and the distance from the bottom end 41 of the guide tube 40 is within 10 mm, for example, between 5 and 10 mm.

[0118] Preferably, the distance h also satisfies: h≤h1-5, preferably h≤h1-10. In this way, even if in actual production, the actual flow velocity of the feed airflow changes appropriately around the preset flow velocity value V1, or the actual flow velocity of the cooling airflow changes appropriately around the preset flow velocity value V2, it can still be ensured that a stable airflow from inside to outside is formed at the lower end of the barrier cylinder 50, thereby preventing dust at the feeding pipe 21 from moving inward to the single crystal silicon rod, and promoting the transfer of foreign matter around the single crystal silicon rod to the feeding pipe 21, greatly improving the cleanliness of the air around the growing single crystal silicon rod, and ensuring the quality of the single crystal silicon.

[0119] Preferably, the distance h also satisfies: h≥h1-50. In this way, not only can a stable airflow from inside to outside be formed at the lower end of the barrier cylinder 50, solving the problem of dust contacting the growing single crystal silicon rod, but also the stability of the airflow can be ensured, and strong and rapid turbulence can be avoided, thereby facilitating the stability of the thermal field and the liquid level stability of the melt, and ensuring the success rate of crystal pulling and production efficiency.

[0120] For example, h is controlled between h1-50 and h1, or between h1-50 and h1-5, more preferably between h1-30 and h1-5, or between h1-30 and h1-10.

[0121] Next, an embodiment of the present invention further provides a control method for a crystal pulling system 100 , which can be used to actually control the crystal pulling system 100 in the production of single crystal silicon.

[0122] Specifically, the control method includes:

[0123] The flow rates of the feed airflow of the first air supply device 22 and the cooling airflow of the second air supply device 30 are controlled so that an airflow from inside to outside is formed at the lower end of the barrier cylinder 50 .

[0124] In this way, the control method controls the flow rate of the feed airflow and the cooling airflow so that a stable airflow from the inside to the outside is formed at the lower end of the barrier cylinder 50, thereby forming an airflow from the growing single crystal silicon rod through the lower end of the barrier cylinder 50 to the feeding pipe 21 as a whole, thereby not only preventing the dust at the feeding pipe 21 from moving inward to the single crystal silicon rod, but also promoting the transfer of foreign matter around the single crystal silicon rod to the feeding pipe 21, thereby greatly improving the air cleanliness around the growing single crystal silicon rod and ensuring the quality of the single crystal silicon.

[0125] In a specific embodiment, Figure 4 , the control method specifically includes:

[0126] The lower end of the collection barrier tube 50 is higher than the bottom end 41 of the guide tube 40 by a distance H;

[0127] Control the flow rate value v1 of the feed airflow and the flow rate value v2 of the cooling airflow to meet v2 2 +0.3v2+v1 2 -2v1-2-0.01H≥k; where k≥0 and is a constant, the units of v1 and v2 are m / s, and the unit of H is mm.

[0128] So, when v2 2 +0.3v2+v1 2 When the condition of -2v1-2-0.01H≥k≥0 is met, an airflow from inside to outside is formed at the lower end of the barrier cylinder 50, which can prevent the dust at the feeding pipe 21 from moving inward to the single crystal silicon rod, and promote the transfer of foreign matter around the single crystal silicon rod to the feeding pipe 21, thereby greatly improving the cleanliness of the air around the growing single crystal silicon rod and ensuring the quality of the single crystal silicon.

[0129] Preferably, v2 2 +0.3v2+v1 2 -2v1-2-0.01H≤k1, wherein k<k1≤10, preferably, k1≤8, and more preferably, k1≤5. In this way, not only can a stable airflow from inside to outside be formed at the lower end of the barrier cylinder 50, solving the problem of dust contacting the growing single crystal silicon rod, but also the stability of the airflow can be ensured, avoiding excessive airflow speed, that is, avoiding strong and rapid turbulence, thereby facilitating the stability of the thermal field and the liquid level stability of the melt, and ensuring the success rate of crystal pulling and production efficiency.

[0130] In one embodiment, v2 2 +0.3v2+v1 2-2v1-2-0.01H can represent the flow velocity of the airflow from inside to outside formed at the lower end of the barrier tube 50, in m / s. By the definition of k and k1, that is, the lower end of the barrier tube 50 not only forms an airflow from inside to outside, but also has a flow velocity between 0 and 10 m / s, or preferably between 0 and 8 m / s, or even between 0 and 5 m / s.

[0131] In another embodiment, reference Figure 5 , the control method specifically includes:

[0132] Collect the distance h that the lower end of the barrier cylinder 50 is higher than the highest liquid level line of the melt in the crucible assembly 10;

[0133] Control the flow rate value v1 of the feed airflow and the flow rate value v2 of the cooling airflow to meet v2 2 +0.3v2+v1 2 -2v1-2-0.01(h-10)≥k; where k≥0 and is a constant, the unit of v1 and v2 is m / s, and the unit of h is mm.

[0134] So, when v2 2 +0.3v2+v1 2 When the condition of -2v1-2-0.01(h-10)≥k≥0 is met, an airflow from inside to outside is formed at the lower end of the barrier cylinder 50, which can prevent the dust at the feeding pipe 21 from moving inward to the single crystal silicon rod, and promote the transfer of foreign matter around the single crystal silicon rod to the feeding pipe 21, thereby greatly improving the cleanliness of the air around the growing single crystal silicon rod and ensuring the quality of the single crystal silicon.

[0135] More preferably, the flow rate value v1 of the feed airflow and the flow rate value v2 of the cooling airflow are controlled to satisfy v2 2 +0.3v2+v1 2 -2v1-2-0.01(h-5)≥k.

[0136] Preferably, v2 2 +0.3v2+v1 2 -2v1-2-0.01(h-10)≤k1, wherein k<k1≤10, preferably, k1≤8, and more preferably, k1≤5. In this way, it can not only ensure that a stable airflow from the inside to the outside is formed at the lower end of the barrier tube 50 to solve the problem of dust contacting the growing single crystal silicon rod, but also ensure the stability of the airflow and avoid excessive airflow speed, that is, avoid strong and rapid turbulence, which is beneficial to the stability of the thermal field and the liquid level stability of the melt, and ensure the success rate of crystal pulling and production efficiency.

[0137] In one embodiment, v2 2 +0.3v2+v1 2-2v1-2-0.01(h-10) can represent the flow velocity of the airflow from inside to outside formed at the lower end of the barrier cylinder 50, and the unit of the flow velocity is m / s.

[0138] In addition, in a specific implementation, the flow rate value v1 of the feed air flow can be controlled by controlling the operation of the first air supply device 22. For example, the first air supply device 22 includes a first driver (such as a fan or an air pump), and the air flow rate at the exhaust port of the first driver is the flow rate value v1 of the feed air flow; but it is not limited to this. For example, the flow rate value v1 of the feed air flow can also be represented by the air flow rate at the air flow inlet of the feeding pipe 21.

[0139] Alternatively, the flow rate value v2 of the cooling airflow can be controlled by controlling the operation of the second driver 32 of the second air supply device 30. For example, the airflow rate at the exhaust port of the second driver 32 is the flow rate value v2 of the cooling airflow; but not limited to this, for example, the flow rate value v2 of the cooling airflow can also be represented by the airflow rate at the air flow inlet of the air supply channel 31 of the second air supply device 30.

[0140] In addition, other configurations and operations of the crystal pulling system 100 according to the embodiment of the present invention are known to those skilled in the art and will not be described in detail herein.

[0141] In summary, the present invention has the following beneficial effects: it realizes the height design optimization of the barrier cylinder 50, or realizes the flow rate control of the cooling airflow and the feeding airflow, so that the lower end of the barrier cylinder 50 can form a stable airflow from the inside to the outside, thereby forming an overall airflow from the growing single crystal silicon rod through the lower end of the barrier cylinder 50 to the feeding pipe 21, thereby not only avoiding the dust at the feeding pipe 21 from moving inward to the single crystal silicon rod, but also promoting the transfer of foreign matter around the single crystal silicon rod to the feeding pipe 21, greatly improving the air cleanliness around the growing single crystal silicon rod, and ensuring the quality of the single crystal silicon; moreover, the technology has strong versatility, can cope with a variety of production conditions of different single crystal silicon, can ensure the quality of the grown single crystal silicon, and has important guiding significance in actual production.

[0142] In the description of this specification, the description with reference to the terms "an implementation mode", "an embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0143] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A crystal pulling system, comprising: A crucible assembly, comprising an outer crucible and an inner crucible, wherein the outer crucible surrounds the outside of the inner crucible, and the interior of the inner crucible forms a crystal growth zone; A feeding assembly, comprising a feeding pipe and a first gas supply device, wherein the lower end of the feeding pipe extends between the outer crucible and the inner crucible, and the first gas supply device is connected to the feeding pipe to supply a feeding gas flow to the feeding pipe; A second gas supply device, which is located above the crucible assembly and supplies a cooling gas flow downward; A guide tube, which is located between the second gas supply device and the crucible assembly and has a bottom end portion extending to the inner side of the inner crucible; characterized in that: The crystal pulling system further includes a barrier tube; the barrier tube surrounds the feeding tube and the inner crucible, is connected to the guide tube and extends downward from the guide tube, and the lower end of the barrier tube is higher than the bottom end of the guide tube and the height difference H≤H1, H1=100V2 2 +30V2+100V1 2 -200V1-200; Among them, V1 is the preset value of the flow rate of the feeding airflow, the unit is m / s; V2 is the preset value of the flow rate of the cooling airflow, the unit is m / s; H and H1 are in mm.

2. The crystal pulling system according to claim 1, characterized in that: A height difference H between the lower end of the barrier tube and the bottom end of the guide tube also satisfies H≥H1-50 and / or H≤H1-10.

3. The crystal pulling system according to claim 1, characterized in that: The inner wall of the outer crucible and the outer wall of the inner crucible jointly define a melting zone, the feeding pipe and the barrier tube both extend downward toward the melting zone, and the melting zone and the crystal growth zone are connected through an opening at the lower part of the inner crucible; Alternatively, the crucible assembly also includes a middle crucible, which is located between the inner crucible and the outer crucible, the inner wall of the outer crucible and the outer wall of the middle crucible jointly define a melting zone, the feeding tube extends downward toward the melting zone, the inner wall of the middle crucible and the outer wall of the inner crucible jointly define a transition zone, the barrier tube is located between the middle crucible and the inner crucible and extends downward toward the transition zone, and the melting zone and the crystal growth zone are connected via the transition zone.

4. The crystal pulling system according to claim 3, characterized in that: The lower end of the barrier tube is lower than at least one of the upper edge of the inner crucible and the upper edge of the middle crucible.

5. The crystal pulling system according to claim 1, characterized in that: The second gas supply device comprises a second driver and a gas supply channel, the second driver is connected to the gas supply channel, and the gas supply channel is located above the center of the inner crucible and extends vertically; The crystal pulling system further includes a control device, which collects a preset flow rate value V1 of the feed air flow and a preset flow rate value V2 of the cooling air flow, and controls the operation of the first air supply device and the second air supply device.

6. A method for designing a crystal pulling system, the crystal pulling system comprising: A crucible assembly comprising an outer crucible and an inner crucible, wherein the outer crucible surrounds the outer portion of the inner crucible; a feeding tube, the lower end of which extends between the outer crucible and the inner crucible; A flow guide tube is located above the crucible assembly and extends downward to the inner side of the inner crucible; wherein the design method comprises the following steps: Collecting a preset flow rate value V1 of the feeding airflow and a preset flow rate value V2 of the cooling airflow in the feeding pipe; The barrier tube is designed to be located between the feeding tube and the inner crucible and connected to the guide tube at the top so that the lower end of the barrier tube is higher than the highest liquid level line of the melt in the crucible assembly. h≤h1=100V2 2 +30V2+100V1 2 -200V1-190; The unit of V1 and V2 is m / s; the unit of h and h1 is mm.

7. The method for designing a crystal pulling system according to claim 5, characterized in that: The distance h also satisfies: h≤h1-5, and / or, h≥h1-50.

8. A control method for a crystal pulling system, the crystal pulling system comprising: A crucible assembly comprising an outer crucible and an inner crucible, wherein the outer crucible surrounds the outer portion of the inner crucible; A feeding assembly, comprising a feeding pipe and a first gas supply device, wherein the lower end of the feeding pipe extends between the outer crucible and the inner crucible, and the first gas supply device is connected to the feeding pipe to supply a feeding gas flow to the feeding pipe; A second gas supply device, which is located above the crucible assembly and supplies a cooling gas flow downward; A guide tube, which is located between the second gas supply device and the crucible assembly and has a bottom end portion extending to the inner side of the inner crucible; characterized in that: The crystal pulling system further includes a barrier tube, which is located between the feeding tube and the inner crucible and is connected to the guide tube and extends downward from the guide tube; The control method comprises: The flow rates of the feed airflow of the first air supply device and the cooling airflow of the second air supply device are controlled so that an airflow from inside to outside is formed at the lower end of the barrier cylinder.

9. The control method of the crystal pulling system according to claim 8, characterized in that: The control method further includes: collecting a distance H by which the lower end of the barrier tube is higher than the bottom end of the guide tube; The "controlling the flow rates of the feed airflow of the first air supply device and the cooling airflow of the second air supply device so that an airflow from inside to outside is formed at the lower end of the barrier cylinder" is: controlling the flow rate value v1 of the feed airflow and the flow rate value v2 of the cooling airflow to satisfy v2 2 +0.3v2+v1 2 -2v1-2-0.01H≥k; where k≥0 and is a constant, the units of v1 and v2 are m / s, and the unit of H is mm.

10. The control method of the crystal pulling system according to claim 8, characterized in that: The control method further comprises: collecting a distance h at which the lower end of the barrier cylinder is above the highest liquid level line of the melt in the crucible assembly; The "controlling the flow rates of the feed airflow of the first air supply device and the cooling airflow of the second air supply device so that an airflow from inside to outside is formed at the lower end of the barrier cylinder" is: controlling the flow rate value v1 of the feed airflow and the flow rate value v2 of the cooling airflow to satisfy v2 2 +0.3v2+v1 2 -2v1-2-0.01(h-10)≥k; where k≥0 and is a constant, the unit of v1 and v2 is m / s, and the unit of h is mm.

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