Single crystal furnace and supplementary doping method
By designing a movable and flip-over doping device in the single crystal furnace, the problems of splattering and insufficient dopant in the single crystal silicon doping process were solved, enabling precise dopant addition and reducing splashing, thereby improving the resistivity and quality of single crystal silicon.
Patent Information
- Application Number
- CN202511725401.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-21
- Publication Date
- 2026-02-17
AI Technical Summary
Existing methods for supplementing doping of monocrystalline silicon are prone to doping explosions, and the dopant content is insufficient, making it difficult to meet the requirements for resistivity of monocrystalline silicon.
A doping device for a single crystal furnace was designed, including a control mechanism that drives the doping hopper to move between an initial height, a preheating height, and a doping height, and flips and switches between a carrying state and a releasing state. By preheating and precisely controlling the addition of dopants, dopant splashing and molten silicon splashing are reduced.
It effectively suppresses the dopant explosion caused by excessive temperature difference, ensures accurate dopant content, prevents molten silicon from splashing onto the inner wall of the furnace, and improves the quality of monocrystalline silicon.
Smart Images
Figure CN121538722A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of photovoltaics, in particular to a single crystal furnace and a method for supplementing dopants. BACKGROUND
[0002] Single crystal silicon is an important material for preparing crystalline silicon solar cells, and the Czochralski method is one of the most important methods for growing single crystal silicon. As the single crystal silicon is drawn, the molten silicon liquid and the dopant in the single crystal furnace will gradually decrease, so in order to ensure that the resistivity is within the ideal range, it is necessary to supplement the dopant into the single crystal furnace.
[0003] However, the current supplementing method is prone to the phenomenon of explosive doping, and there is a problem of insufficient actual addition of dopants, which makes it difficult for the resistivity of single crystal silicon to meet the requirements, affecting the quality of single crystal silicon. SUMMARY
[0004] Therefore, it is necessary to provide a single crystal furnace and a method for supplementing dopants in view of the problem of explosive doping in the supplementing process.
[0005] A single crystal furnace includes a furnace body and a supplementing device, the supplementing device includes:
[0006] a main body installed in the furnace body;
[0007] a supplementing hopper with an open end located in the furnace body; and
[0008] a control mechanism with one end limited to the main body and the other end connected to the supplementing hopper;
[0009] wherein the control mechanism is used to drive the supplementing hopper to move between an initial height, a preheating height and a supplementing height; and when the supplementing hopper is at the supplementing height, the control mechanism is used to drive the supplementing hopper to switch between a carrying state with the open end upward and a releasing state with the open end downward.
[0010] In one embodiment, the control mechanism includes a first flexible member and a second flexible member, one end of the first flexible member and one end of the second flexible member are respectively limited to the main body, and the other end of the first flexible member and the other end of the second flexible member are respectively connected to opposite sides of the open end of the supplementing hopper.
[0011] The end of the first flexible member and the second flexible member connected to the supplementing hopper can move back and forth in a direction, so as to drive the supplementing hopper to move between the initial height, the preheating height and the supplementing height, and to drive the supplementing hopper to switch between the carrying state and the releasing state.
[0012] In one of the embodiments, the material of the first flexible member comprises tungsten, and / or the material of the second flexible member comprises tungsten.
[0013] In one of the embodiments, the main body comprises a first reel and a second reel, both of which are rotatable, one end of the first flexible member is wound around the first reel, and one end of the second flexible member is wound around the second reel.
[0014] In one of the embodiments, the main body further comprises a telescopic member, the first flexible member and the second flexible member are connected to the doping bucket at one end close to the central axis of the furnace body via the telescopic member.
[0015] The telescopic member is movable in one direction to switch the doping bucket between a first horizontal position away from the central axis of the furnace body and a second horizontal position close to the central axis of the furnace body.
[0016] In one of the embodiments, the telescopic member is provided with a pulley support unit at one end close to the central axis of the furnace body, and the first flexible member and the second flexible member are wound around the pulley support unit.
[0017] In one of the embodiments, the main body further comprises a trigger member, and the telescopic member is configured to trigger the trigger member when the doping bucket is in the second position.
[0018] In one of the embodiments, the single crystal furnace further comprises a visual acquisition unit configured to acquire an image inside the furnace when the telescopic member triggers the trigger member.
[0019] In one of the embodiments, the material of the doping bucket comprises molybdenum.
[0020] A doping method using the single crystal furnace described above, the doping method comprising:
[0021] Controlling the doping bucket to move from an initial height to a preheating height;
[0022] When the time length that the doping bucket stays at the preheating height reaches a preset preheating time length, controlling the doping bucket to move from the preheating height to a doping height;
[0023] Turning the doping bucket from a bearing state to a release state;
[0024] When the time length that the doping bucket stays at the release state reaches a preset release time length, controlling the doping bucket to turn from the release state to the bearing state and move from the doping height to the initial height.
[0025] In one embodiment, prior to the step of moving the control mixing hopper a preset distance from its initial height to the preheating height, the method further includes:
[0026] The mixing hopper is controlled to move from a first horizontal position away from the central axis of the furnace body to a second horizontal position close to the central axis of the furnace body.
[0027] In one embodiment, the step of controlling the mixing hopper to move from the initial height to the preheating height includes:
[0028] Control the addition hopper to move from the initial height to the initial preheating height;
[0029] If the time the mixing hopper remains at the initial preheating height reaches a preset initial preheating time, the mixing hopper is controlled to move from the initial preheating height to the preheating height.
[0030] In the aforementioned single-crystal furnace, when the doping hopper is at its initial height, the operator can add dopant. When the doping hopper is at its preheating height, the dopant can be preheated, reducing the temperature difference between the dopant and the molten silicon in the furnace, thus effectively suppressing the doping explosion caused by excessive temperature difference after the dopant enters the molten silicon. When the doping hopper is at its doping height, the operating mechanism can drive the doping hopper to flip and switch to the release state to release the dopant and complete the doping operation. Because the distance between the doping hopper and the liquid surface is relatively close at the doping height, the problem of dopant splashing and adhering to the inner wall of the furnace, resulting in insufficient dopant content, can be effectively reduced. In addition, it can also effectively prevent molten silicon from splashing onto the inner wall of the furnace and affecting the airflow inside the furnace. Attached Figure Description
[0031] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments of this application and their descriptions are used to explain this application and do not constitute an undue limitation of this application.
[0032] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0033] Figure 1 This is a schematic diagram of a single crystal furnace according to an embodiment of this application.
[0034] Figure 2 This is a schematic diagram of the internal structure of a single crystal furnace according to an embodiment of this application when the doping hopper is in the first horizontal position at its initial height.
[0035] Figure 3 forFigure 2 A magnified view of part A of the single crystal furnace shown.
[0036] Figure 4 This is a schematic diagram of the internal structure of a single crystal furnace according to an embodiment of this application when the doping hopper is in the second horizontal position at the initial height.
[0037] Figure 5 This is a schematic diagram of the internal structure of a single crystal furnace according to an embodiment of this application when the doping hopper is at its initial preheating height.
[0038] Figure 6 The figure shows a schematic diagram of the internal structure of a single crystal furnace according to an embodiment of this application when the doping hopper is at the preheating height.
[0039] Figure 7 The figure shows a schematic diagram of the internal structure of a single crystal furnace according to an embodiment of this application when the doping hopper is at the doping height.
[0040] Figure 8 The figure shows a schematic diagram of the internal structure of a single crystal furnace according to an embodiment of this application when the doping hopper is in the released state.
[0041] Figure 9 This is a schematic diagram of a doping method according to an embodiment of this application.
[0042] Explanation of reference numerals in the attached figures:
[0043] 100. Single crystal furnace; 20. Furnace body; 21. Main furnace chamber; 22. Auxiliary furnace chamber; 23. Isolation valve chamber; 24. Crucible; 25. Main heater; 26. Bottom heater; 40. Doping device; 41. Main body; 412. Outer shell; 414. Driving component; 416. Telescopic component; 418. Pulley support unit; 43. Doping hopper; 45. Control mechanism; 452. First flexible component; 454. Second flexible component. Detailed Implementation
[0044] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.
[0045] In the description of this application, it should be understood that if terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.
[0046] Furthermore, where the terms "first" and "second" appear, these terms are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, where the term "multiple" appears, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.
[0047] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.
[0048] In this application, unless otherwise expressly specified and limited, the use of descriptions such as "above" or "below" the second feature indicates that the first and second features are in direct contact or indirect contact via an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. Similarly, "below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.
[0049] It should be noted that if an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. If an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. If so, the terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application are for illustrative purposes only and do not represent the only possible implementation.
[0050] See Figure 1 An embodiment of this application provides a single crystal furnace 100, including a furnace body 20 and a doping device 40. The furnace body 20 is used to form a crystal rod and complete the annealing process of the crystal rod, and the doping device 40 is used to replenish dopant into the furnace body 20.
[0051] The furnace body 20 includes a main furnace chamber 21, an auxiliary furnace chamber 22, and an isolation valve chamber 23. The auxiliary furnace chamber 22 is located above the main furnace chamber 21, and the isolation chamber 23 is located between the main furnace chamber 21 and the auxiliary furnace chamber 22. The main furnace chamber 21 contains a crucible 24, a main heater 25 located outside the crucible 24, and a bottom heater 26 located at the bottom of the crucible 24. It can be understood that the structure of the furnace body 20 is not limited to this and can be configured as needed to meet different requirements.
[0052] The basic principle of crystal pulling is as follows: the raw material is placed in the crucible 24, and there is a rotating and lifting seed crystal rod above the crucible 24. A seed crystal is fixed at the lower end of the rod. After the raw material is heated and melted by the main heater 25 and the bottom heater 26, the seed crystal is inserted into the crucible 24. The appropriate heating temperature is controlled to reach the supersaturation temperature. Then, the crystal is pulled while rotating to obtain the desired single crystal silicon rod.
[0053] In some embodiments, the method for producing a single-crystal silicon rod includes: melting silicon, crystal pulling, shoulder formation, shoulder rotation, equal diameter formation, finishing, and furnace shutdown.
[0054] In the silicon melting stage, the crystalline silicon raw material is placed in crucible 24, and the heater is turned on to melt the raw material. In the crystal pulling stage, a seed crystal is introduced into the molten silicon. By reducing the diameter of the seed crystal to a certain extent and growing it to a sufficient length, it is discharged to the surface using the angle of dislocation growth. In the shoulder forming stage, the crystal diameter is gradually increased to the required diameter through the combined control of temperature and pulling speed.
[0055] During the shoulder-forming stage, by increasing the temperature and pulling speed, the crystal diameter stops growing and begins to grow at a constant length. In the constant-diameter stage, temperature and pulling speed are controlled to maintain constant-diameter growth. In the finishing stage, when the crystal reaches the required product length, the crystal diameter is rapidly reduced by increasing the temperature and pulling speed, ultimately forming a tail that detaches from the liquid surface to obtain the desired single-crystal silicon rod. After furnace shutdown, the single-crystal furnace 100 is disassembled, cleaned, dried, and then reassembled for future use.
[0056] like Figure 2 , Figure 3 As shown, the blending device 40 includes a main body 41, a blending hopper 43, and a control mechanism 45. The main body 41 is installed in the furnace body 20; in one embodiment, the main body 41 is installed in the isolation valve chamber 23. The blending hopper 43, open at one end, is located inside the furnace body 20. One end of the control mechanism 45 is confined to the main body 41, and the other end is connected to the blending hopper 43. The control mechanism 45 is used to move the blending hopper 43 at an initial height (e.g., ...). Figure 4 (as shown), preheating height (e.g.) Figure 5 , Figure 6 (as shown) and the height of the additive (as shown) Figure 7 (As shown) The mixing hopper 43 moves between the loading state with the opening end facing upwards and the release state with the opening end facing downwards (as shown). When the mixing hopper 43 is at the mixing height, the control mechanism 45 is used to drive the mixing hopper 43 between the loading state with the opening end facing upwards and the release state with the opening end facing downwards (as shown). Figure 8 Switch between the two (as shown).
[0057] The phrase "open end facing down" in the above-mentioned doping hopper 43 includes the opening end 43 facing the crucible 24 directly below, and also includes the furnace wall facing the furnace body 20, as long as it is possible to pour the dopant into it.
[0058] Thus, when the doping hopper 43 is at its initial height, the operator can add dopant to it. When the doping hopper 43 is at its preheating height, the dopant can be preheated to reduce the temperature difference between the dopant and the molten silicon in the furnace body 20, thereby effectively suppressing the dopant from exploding due to excessive temperature difference after entering the molten silicon.
[0059] When the doping hopper 43 is at the doping height, the operating mechanism can drive the doping hopper 43 to flip and switch to the release state to release the dopant and complete the doping operation. Since the distance between the doping hopper 43 at the doping height and the liquid surface is relatively close, the problem of dopant splashing and adhering to the inner wall of the furnace body 20, resulting in insufficient actual dopant content, can be effectively reduced. In addition, it can also effectively prevent molten silicon liquid from splashing onto the inner wall of the furnace body 20 and affecting the airflow inside the furnace.
[0060] It is understood that the initial height, preheating height, and supplementary doping height are all based on the liquid surface of the molten silicon. The preheating height is less than the initial height, and the supplementary doping height is less than the preheating height. The specific heights of the initial height, preheating height, and supplementary doping height can be set as needed.
[0061] In some embodiments, when the doping hopper 43 is at its initial height, the distance between the doping hopper 43 and the surface of the molten silicon is 1000±30mm. When the doping hopper 43 is at its preheating height, the distance between the doping hopper 43 and the surface of the molten silicon is 470mm-530mm; optionally, the distance between the doping hopper 43 and the surface of the molten silicon is 500mm. When the doping hopper 43 is at its doping height, the distance between the doping hopper 43 and the surface of the molten silicon is 50mm-80mm.
[0062] Please continue reading. Figure 2 , Figure 3 The doping hopper 43 is a hollow shell structure with one open end. In one embodiment, the doping hopper 43 is a cubic structure with one open end. When the doping hopper 43 is in the loaded state, the open end of the doping hopper 43 faces upward, so the dopant can be placed into the doping hopper 43 through the open end. When the doping hopper 43 is in the released state, the open end of the doping hopper 43 faces downward, so the dopant in the doping hopper 43 can be poured out through the open end. It can be understood that the shape and size of the doping hopper 43 can be set as needed to meet different doping requirements.
[0063] In some embodiments, the material of the doping hopper 43 includes molybdenum, thus maintaining high strength and hardness at high temperatures without cracking due to heat, which could lead to doping failure or contamination of the molten silicon. It is understood that the material of the doping hopper 43 is not limited to this and can be configured as needed to meet different doping requirements.
[0064] The control mechanism 45 includes a first flexible member 452 and a second flexible member 454. Both the first flexible member 452 and the second flexible member 454 are elongated flexible structures. One end of the first flexible member 452 and one end of the second flexible member 454 are respectively confined to the main body 41, and the other ends of the first flexible member 452 and the second flexible member 454 are respectively connected to opposite sides of the opening end of the mixing hopper 43. In this way, the mixing hopper 43 is suspended in the furnace body 20 by the first flexible member 452 and the second flexible member 454.
[0065] In some embodiments, the material of the first flexible element 452 and / or the first flexible element 454 includes tungsten, and the first flexible element 452 and / or the first flexible element 454 is a tungsten wire, which has good toughness, wear resistance and high temperature resistance. It is understood that the materials of the first flexible element 452 and the second flexible element 454 are not limited to this, and can be set as needed to meet different requirements.
[0066] Furthermore, the end of the first flexible member 452 and the second flexible member 454 connected to the mixing hopper 43 can reciprocate in one direction, thereby driving the mixing hopper 43 to move between the initial height, the preheating height, and the mixing height, and driving the mixing hopper 43 to flip and switch between the carrying state and the releasing state. In one embodiment, the end of the first flexible member 452 and the second flexible member 454 connected to the mixing hopper 43 reciprocates in the vertical direction.
[0067] Thus, on the one hand, the end of the first flexible member 452 and the second flexible member 454 connected to the mixing hopper 43 can move synchronously in the vertical direction, thereby driving the mixing hopper 43 to move between the initial height, the preheating height, and the mixing height. On the other hand, as... Figure 8 As shown, the first flexible member 452 and the second flexible member 454 are connected to one end of the mixing hopper 43, which can move asynchronously in the vertical direction, thereby driving the mixing hopper 43 to flip and switch between the carrying state and the releasing state.
[0068] like Figure 7 As shown, when the mixing hopper 43 is under load, the end of the first flexible member 452 connected to the mixing hopper 43 and the end of the second flexible member 454 connected to the mixing hopper 43 are on the same horizontal plane. Figure 8 As shown, when the mixing hopper 43 needs to switch from the bearing state to the releasing state, the first flexible member 452 remains stationary, while the end of the second flexible member 454 connected to the mixing hopper 43 moves downward a certain distance, thereby causing the mixing hopper 43 to flip downward and switch to the releasing state with the open end facing downward. Figure 7 As shown, when the mixing hopper 43 needs to switch from the release state to the load state, the first flexible member 452 remains stationary, while the end of the second flexible member 454 connected to the mixing hopper 43 moves upward a certain distance, thereby causing the mixing hopper 43 to flip upward and switch to the release state with the opening end facing upward.
[0069] Please continue reading. Figure 2 , Figure 3 In some embodiments, the main body 41 includes a housing 412, a drive member 414, a first take-up wheel, and a second take-up wheel.
[0070] The isolation chamber 23 of the furnace body 20 has a reserved installation port on its side wall. The outer shell 412 has a hollow cylindrical structure. One end of the outer shell 412 is installed in the furnace body 20 through the reserved installation port, and the other end of the outer shell 412 extends horizontally away from the furnace body 20 to serve as a fixation, support, and storage unit. It can be understood that the shape of the outer shell 412 is not limited to this and can be designed to meet different requirements.
[0071] The drive element 414 is at least partially housed within the housing 412 or mounted on the end of the housing 412 away from the furnace body 20. In some embodiments, the drive element 414 is a servo motor. It is understood that the type of drive element 414 is not limited to this and can be configured as needed to meet different driving requirements. The single crystal furnace 100 also includes a control system, which is communicatively connected to the drive element 414 and is used to control the operating state of the drive element 414.
[0072] The first and second retractable wheels are housed within the outer casing 412 and are respectively connected to the drive member 414, thus rotating under the control of the drive member 414. One end of the first flexible member 452 is retractably wound around the first retractable wheel, so the first retractable wheel can retract or release the first flexible member 452 by rotating, thereby driving the other end of the first flexible member 452 to rise and fall vertically. One end of the second flexible member 454 is retractably wound around the second retractable wheel, so the second retractable wheel can retract or release the second flexible member 454 by rotating, thereby driving the other end of the second flexible member 454 to rise and fall vertically.
[0073] In some embodiments, the main body 41 further includes a telescopic member 416, which has a rod-like structure. One end of the telescopic member 416 is located inside the outer shell 412 and is connected to the drive member 414. The other end of the telescopic member 416 extends out of the outer shell 412 toward the central axis of the furnace body 20. The first flexible member 452 and the second flexible member 454 respectively bypass the end of the telescopic member 416 near the central axis of the furnace body 20 and are connected to the mixing hopper 43.
[0074] The telescopic member 416 can reciprocate in one direction under the drive of the driving member 414. Since the first flexible member 452 and the second flexible member 454 are respectively arranged around the end of the telescopic member 416 near the central axis of the furnace body 20, the movement of the telescopic member 416 can change the distance between the end of the first flexible member 452 and the second flexible member 454 connected to the mixing hopper 43 and the side wall of the furnace body 20, thereby allowing the mixing hopper 43 to switch between a first horizontal position away from the central axis of the furnace body 20 and a second horizontal position close to the central axis of the furnace body 20. In one embodiment, the telescopic member 416 reciprocates in a horizontal direction under the drive of the driving member 414.
[0075] When the doping device 40 is not in operation, the telescopic member 416 moves away from the central axis of the furnace body 20 so that the doping hopper 43 is in a first horizontal position, thereby preventing interference with the normal crystal pulling process. When the doping device 40 is in operation, the telescopic member 416 moves closer to the central axis of the furnace body 20 so that the doping hopper 43 is in a second horizontal position, thereby facilitating the doping operation.
[0076] In some embodiments, the telescopic member 416 is provided with a pulley support unit 418 at one end near the central axis of the furnace body 20, and the first flexible member 452 and the second flexible member 454 respectively pass around the pulley support unit 418 to connect to the mixing hopper 43. The pulley support unit 418 is used to provide support so that the first flexible member 452 and the second flexible member 454 can move up and down smoothly.
[0077] In some embodiments, the main body 41 further includes a trigger element located within the housing 412. The telescopic member 416 triggers the trigger element when the supplementary mixing hopper 43 is in the second horizontal position, thereby enabling the control system to accurately determine the position of the supplementary mixing hopper 43 and subsequently control the operating state of the drive member 414. In one embodiment, the trigger element is a proximity switch. When the supplementary mixing hopper 43 is in the second horizontal position, the telescopic member 416 contacts the trigger element, causing the trigger element to be in a triggered state.
[0078] In some embodiments, the single crystal furnace 100 further includes a vision acquisition unit located within the furnace body 20. The vision acquisition unit is used to acquire images within the furnace body 20 when the telescopic member 416 triggers the trigger, thereby further verifying the position of the doping hopper 43 and thus precisely controlling the working state of the drive member 414. In one embodiment, the vision acquisition unit is a camera.
[0079] The aforementioned single crystal furnace 100, because the doping hopper 43 can be preheated close to the surface of the molten silicon, reduces the temperature difference between the dopant and the molten silicon, effectively reducing the risk of doping explosion and silicon splashing. Moreover, the amount of dopant volatilized and wasted during the doping process is negligible, thus allowing the dosage of dopant added to be precisely controlled.
[0080] like Figure 9 As shown, this application also provides a method for supplementary doping using the aforementioned single-crystal furnace 100. When the single-crystal silicon rod is removed or the lead-in process is performed more than twice, supplementary doping can be performed. The supplementary doping method includes the following steps:
[0081] Step S100: Control the mixing hopper to move from a first horizontal position away from the central axis of the furnace body to a second horizontal position closer to the central axis of the furnace body.
[0082] Please combine Figure 2 , Figure 4As shown, under the control of the control system, the drive component 414 drives the telescopic component 416 to move towards the central axis of the furnace body 20, causing the mixing hopper 43 to move from a first horizontal position away from the central axis of the furnace body 20 to a second horizontal position closer to the central axis of the furnace body 20. At this time, the furnace pressure inside the furnace body 20 is 3 torr - 5 torr, which can be selected as 4 torr, and the argon flow rate is 80 pm to 150 pm, which can be selected as 100 pm. The lower furnace pressure combined with the larger flow rate of argon can increase the gas velocity inside the furnace body 20, which helps to remove the oxides generated during the production process.
[0083] Step S200: Control the mixing hopper to move from the initial height to the preheating height.
[0084] In some embodiments, please combine Figure 5 , Figure 6 As shown, under the control of the control system, the drive component 414 drives the first and second take-up and release wheels to rotate at a certain angle to release the first flexible component 452 and the second flexible component 454, thereby moving the dopant hopper 43 from the initial height to the preheating height. In this way, the dopant in the dopant hopper 43 is preheated in the main furnace chamber 21 to reduce the temperature difference between the dopant and the molten silicon, thereby reducing the probability of dopant explosion and silicon sputtering. At this time, the furnace pressure inside the furnace body 20 is 3 torr - 5 torr, optionally 4 torr, and the argon flow rate is 80 pm to 150 pm, optionally 100 pm.
[0085] In some embodiments, step S200 includes:
[0086] S210: Control the mixing hopper to move from the initial height to the initial preheating height.
[0087] In some embodiments, such as Figure 5 As shown, under the control of the control system, the drive component 414 drives the first take-up and release wheel to rotate at a certain angle. The first flexible component 452, connected to one end of the dopant hopper 43, and the second flexible component 454, connected to one end of the dopant hopper 43, move downwards until the dopant hopper 43 moves from the initial height to the initial preheating height. The dopant in the dopant hopper 43 undergoes preliminary preheating in the main furnace chamber 21. At this time, the furnace pressure in the furnace body 20 is 3 torr - 5 torr, which can be selected as 4 torr, and the argon flow rate is 80 pm to 150 pm, which can be selected as 100 pm.
[0088] In some embodiments, when the doping hopper 43 is at the initial preheating height, the distance between the doping hopper 43 and the surface of the molten silicon is 1000±30mm. Optionally, the distance between the doping hopper 43 and the surface of the molten silicon is 1000mm. It is understood that the specific value of the distance between the doping hopper 43 and the surface of the molten silicon when the doping hopper 43 is at the initial preheating height is not limited to this, and can be set as needed to meet different preheating requirements.
[0089] Step S220: When the time when the mixing hopper is at the initial preheating height reaches the preset initial preheating time, control the mixing hopper to move from the initial preheating height to the preheating height.
[0090] In some embodiments, such as Figure 6 As shown, the control system acquires the duration for which the dopant hopper 43 remains at the initial preheating height. When the duration of the dopant hopper 43 at the initial preheating height reaches the preset initial preheating time, the drive component 414, under the control of the control system, drives the first take-up and release wheel to rotate at a certain angle to continue releasing the first flexible component 452 and the second flexible component 454. The end of the first flexible component 452 connected to the dopant hopper 43 and the end of the second flexible component 454 connected to the dopant hopper 43 continue to move downwards until the dopant hopper 43 moves from the initial preheating height to the preheating height, and the dopant in the dopant hopper 43 continues to heat up in the main furnace chamber 21. At this time, the furnace pressure in the furnace body 20 is 3 torr-5 torr, which can be selected as 4 torr, and the argon flow rate is 80 pm-150 pm, which can be selected as 100 pm.
[0091] In some embodiments, the preset initial preheating time is 1 min to 5 min, optionally 5 min. When the doping hopper 43 is at the preheating height, the distance between the doping hopper 43 and the surface of the molten silicon is 470 mm to 530 mm, optionally 500 mm. It is understood that the specific value of the preset initial preheating time is not limited to these values, and the specific value of the distance between the doping hopper 43 and the surface of the molten silicon when the doping hopper 43 is at the preheating height is not limited to these values; it can be set as needed to meet different preheating requirements.
[0092] In this way, the doping hopper 43 can be at the initial preheating height and the preheating height successively to preheat the dopant, thereby effectively controlling the heating rate of the doping hopper 43 and effectively preventing the doping hopper 43 from cracking due to thermal stress concentration caused by excessive heating rate, which would lead to doping failure or silicon liquid contamination.
[0093] After step S200, step S300 is also included: when the time when the supplementary mixing hopper is at the preheating height reaches the preset preheating time, the supplementary mixing hopper is controlled to move from the preheating height to the supplementary mixing height.
[0094] In some embodiments, such asFigure 7 As shown, the control system acquires the duration for which the doping hopper 43 is at the preheating height. When the preheating height reaches the preset preheating time, the drive unit 414, under the control of the control system, drives the first take-up and release wheel to rotate at a certain angle to continue releasing the first flexible member 452 and the second flexible member 454. The end of the first flexible member 452 connected to the doping hopper 43 and the end of the second flexible member 454 connected to the doping hopper 43 continue to move downwards until the doping hopper 43 moves from the preheating height to the doping height to approach the surface of the molten silicon. At this time, the furnace pressure inside the furnace body 20 is 3 torr - 5 torr, which can be selected as 4 torr, and the argon flow rate is 80 pm to 150 pm, which can be selected as 100 pm.
[0095] In some embodiments, the preset preheating time is 1 min - 5 min. When the doping hopper 43 is at the doping height, the distance between the doping hopper 43 and the liquid surface of the molten silicon is 50 mm - 80 mm. Optionally, the distance between the doping hopper 43 and the liquid surface of the molten silicon is 50 mm. It is understood that the specific value of the preset preheating time is not limited to this, and the specific value of the distance between the doping hopper 43 and the liquid surface of the molten silicon when the doping hopper 43 is at the doping height is not limited to this. It can be set as needed to meet different preheating requirements.
[0096] After step S300, step S400 is also included: the flipping and mixing hopper is switched from the bearing state to the releasing state.
[0097] In some embodiments, such as Figure 8 As shown, under the control of the control system, the drive component 414 drives the second take-up and release wheel to rotate a certain angle to continue releasing the second flexible component 454. The end of the second flexible component 454 connected to the dopant hopper 43 continues to descend a certain distance, thereby causing the dopant hopper 43 to flip from the bearing state to the release state. The open end of the dopant hopper 43 faces downward, and the dopant in the dopant hopper 43 is poured into the molten silicon. At this time, the furnace pressure in the furnace body 20 is 3 torr-5 torr, which can be selected as 3 torr, and the argon flow rate is 80 pm-150 pm, which can be selected as 80 pm. By reducing the argon flow rate, it is possible to prevent the dopant from being blown away by the argon during the addition process.
[0098] After step S400, step S500 is also included: when the duration of the mixing hopper in the release state reaches the preset release duration, the mixing hopper is controlled to flip from the release state to the bearing state and move from the mixing height to the initial height.
[0099] In some embodiments, after the dopant in the doping hopper 43 is completely poured into the molten silicon, under the control of the control system, the drive unit 414 drives the second take-up and discharge wheel to move upward a certain distance and return to the bearing state. The first take-up and discharge wheel and the second take-up and discharge wheel move upward synchronously to move the doping hopper 43 from the doping height to the initial height. At this time, the furnace pressure inside the furnace body 20 is 3 torr - 5 torr, optionally 4 torr, and the argon flow rate is 80 pm to 150 pm, optionally 100 pm.
[0100] After step S500, step S600 is also included: controlling the mixing hopper to move from the second horizontal position to the first horizontal position.
[0101] In some embodiments, under the control of the control system, the drive member 414 drives the telescopic member 416 to move away from the central axis of the furnace body 20, thereby moving the additive hopper 43 from a second horizontal position close to the central axis of the furnace body 20 to a first horizontal position away from the central axis of the furnace body 20. At this time, the furnace pressure inside the furnace body 20 is 3 torr-5 torr, optionally 5 torr, and the argon flow rate is 80 pm-150 pm, optionally 150 pm. In this way, increasing the argon flow rate can purify the furnace body 20 using argon, quickly carrying away the oxides volatilized during additive addition.
[0102] In one embodiment, the preset release time is 1 min to 5 min, and can be selected as 1 min, so that all the dopant in the doping hopper 43 can enter the molten silicon. It is understood that the specific value of the preset release time is not limited to this, and can be set as needed to meet different release requirements.
[0103] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0104] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.
Claims
1. A single crystal furnace, characterized in that, Includes a furnace body and a doping device, wherein the doping device includes: The main body is installed on the furnace body; A mixing hopper with one open end is located inside the furnace body; and The control mechanism has one end located within the main body and the other end connected to the mixing hopper; The control mechanism is used to move the mixing hopper between the initial height, the preheating height, and the mixing height; when the mixing hopper is at the mixing height, the control mechanism is used to drive the mixing hopper to flip and switch between a bearing state with the opening end facing upward and a releasing state with the opening end facing downward.
2. The single crystal furnace according to claim 1, characterized in that, The control mechanism includes a first flexible member and a second flexible member. One end of the first flexible member and one end of the second flexible member are respectively confined to the main body, and the other ends of the first flexible member and the second flexible member are respectively connected to opposite sides of the opening end of the mixing hopper. The first flexible member and the second flexible member are connected to one end of the mixing bucket, which can reciprocate in one direction to drive the mixing bucket to move between the initial height, the preheating height and the mixing height, and drive the mixing bucket to flip and switch between the bearing state and the releasing state.
3. The single crystal furnace according to claim 2, characterized in that, The material of the first flexible element includes tungsten, and / or the material of the second flexible element includes tungsten.
4. The single crystal furnace according to claim 2, characterized in that, The main body includes a first take-up and release wheel and a second take-up and release wheel, both of which are rotatable. One end of the first flexible member is retractably wrapped around the first take-up and release wheel, and one end of the second flexible member is retractably wrapped around the second take-up and release wheel.
5. The single crystal furnace according to claim 2, characterized in that, The main body also includes a telescopic component, and the first flexible component and the second flexible component are respectively connected to the mixing hopper at one end of the telescopic component near the central axis of the furnace body; The telescopic component can reciprocate in one direction to switch the mixing hopper between a first horizontal position away from the central axis of the furnace body and a second horizontal position close to the central axis of the furnace body.
6. The single crystal furnace according to claim 5, characterized in that, The telescopic component is provided with a pulley support unit at one end near the central axis of the furnace body, and the first flexible component and the second flexible component respectively bypass the pulley support unit.
7. The single crystal furnace according to claim 5, characterized in that, The main body also includes a trigger, and the telescopic member is used to trigger the trigger when the mixing hopper is in the second horizontal position.
8. The single crystal furnace according to claim 7, characterized in that, The single crystal furnace also includes a vision acquisition unit, which is used to acquire an image inside the furnace when the telescopic component triggers the trigger component.
9. The single crystal furnace according to claim 1, characterized in that, The material of the mixing hopper includes molybdenum.
10. A method for supplementing doping, characterized in that, The method of supplementing doping using the single crystal furnace as described in any one of claims 1 to 9 includes: Control the mixing hopper to move from the initial height to the preheating height; If the time the supplementary mixing hopper is at the preheating height reaches the preset preheating time, the supplementary mixing hopper is controlled to move from the preheating height to the supplementary mixing height; The mixing hopper is flipped to switch from the bearing state to the releasing state; When the duration of the replenishing hopper in the release state reaches a preset release duration, the replenishing hopper is controlled to flip from the release state to the bearing state and move from the replenishing height to the initial height.
11. The method for supplementing doping according to claim 10, characterized in that, Before the step of controlling the mixing hopper to move a preset distance from its initial height to the preheating height, the method further includes: The mixing hopper is controlled to move from a first horizontal position away from the central axis of the furnace body to a second horizontal position close to the central axis of the furnace body.
12. The method for supplementing doping according to claim 10 or 11, characterized in that, The step of controlling the mixing hopper to move from the initial height to the preheating height includes: Control the addition hopper to move from the initial height to the initial preheating height; If the time the mixing hopper remains at the initial preheating height reaches a preset initial preheating time, the mixing hopper is controlled to move from the initial preheating height to the preheating height.