Large-size continuous single crystal growth device and single crystal growth process

Abstract

The application discloses a large-size continuous single crystal growth device, which comprises a rack, a first electric furnace, a second electric furnace, a pulling mechanism and a positioning mechanism, wherein the rack bears the first electric furnace, the second electric furnace, the pulling mechanism and the positioning mechanism; the second electric furnace is arranged obliquely above the first electric furnace and is used for supplementing the melt of the first electric furnace; the positioning mechanism is arranged between the first electric furnace and the pulling mechanism, one end of the positioning mechanism is positioned and then connected with the first electric furnace; the pulling mechanism is arranged at one end of the rack and is slidingly connected with the rack; the first electric furnace and the second electric furnace are electrically fused quartz sand, the first electric furnace is used for heat preservation of the melt, the positioning mechanism is positioned and installed between the first electric furnace, and a crystal seed is arranged in the positioning mechanism. The application adopts the idea of the steel continuous casting method and combines the semiconductor charcoal type crystal growth technology to propose a continuous crystal growth technology mode; under the condition that the first electric furnace supplements the melt, the second electric furnace is used for heat preservation, and the pulling mechanism is used for stably pulling and growing the crystal, the industrialized continuous crystal growth is realized.

Description

Technical Field

[0001] This invention belongs to the field of silicon dioxide purification and crystallization technology, and specifically relates to a large-size continuous single crystal growth device and single crystal growth process. Background Technology

[0002] Silica is widely used in high-end industries and plays an irreplaceable role in optoelectronic information, semiconductors, photovoltaics and other fields. Depending on the application industry, its application requirements are also different (purity, single crystal, polycrystalline type, etc.). Modern processes usually use directional solidification and Czochralski methods for crystallization and purification.

[0003] Traditional Czochralski crystal growth involves vertical pulling, where one end of a seed crystal is brought into contact with molten quartz sand to initiate crystal growth. The crystal is then slowly pulled up to achieve crystal growth. However, after the crystal has grown to a certain height, growth must be stopped and the seed crystal replaced. Because it is vertical pulling, continuous vertical growth is not possible. Existing single crystal production technologies are all batch-based, resulting in high costs.

[0004] Based on this situation, the applicant developed and formulated a new crystal growth process and supporting equipment, which changed the traditional vertical crystal growth method, broke the mindset of the Czochralski method, adopted the horizontal crystal growth method, and can achieve continuous crystal growth without interruption, without the need to change the crystal seed during the interrupted crystal growth process, and carry out multiple batch growth, which greatly improves the single crystal production capacity. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a large-size continuous single crystal growth device and single crystal growth process. It adopts the idea of ​​steel continuous casting combined with semiconductor diesel crystal growth technology and proposes a continuous crystal growth technology mode. With the addition of molten molten material in the first electric furnace and the use of heat preservation technology in the second electric furnace to stabilize the crystal growth by the pulling mechanism, industrial-scale continuous crystal growth is realized.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A large-size continuous single crystal growth apparatus includes a frame, a first electric furnace, a second electric furnace, a pulling mechanism, and a positioning mechanism. The frame supports the first electric furnace, the second electric furnace, the pulling mechanism, and the positioning mechanism. The second electric furnace is located diagonally above the first electric furnace to replenish the molten metal in the first electric furnace. The positioning mechanism is located between the first electric furnace and the pulling mechanism, with one end of the positioning mechanism positioned and connected to the first electric furnace. The pulling mechanism is located at one end of the frame and slidably connected to the frame. The first and second electric furnaces electrically melt quartz sand. The first electric furnace keeps the molten metal warm. The positioning mechanism is positioned and installed between the first electric furnace and the first electric furnace. The seed crystal is placed in the positioning mechanism, and then the pulling mechanism pulls the seed crystal to achieve the crystal growth process.

[0008] One end of the frame is provided with a fixed plate and a first slide rail, which is used to guide the sliding of the traction mechanism.

[0009] The first and second electric furnaces are rotatably connected to the frame on both sides of the furnace body; one side is equipped with a speed reducer to adjust and control the tilt angle of the furnace body. This is the existing technology for electric furnace control and adjustment. The electric furnace is a conventional medium-frequency electric furnace, which will not be described in detail. The bottom side wall of the first electric furnace is equipped with a flow outlet for drawing out molten quartz sand.

[0010] The positioning mechanism includes a support platform, a support arm, a second slide rail, a support frame, a crystal growth mold, a second slide block, a threaded sleeve, and a lead screw. The support arm is fixedly connected to the frame, the support platform is fixed on the support arm, and the second slide rail is fixed on the support platform. The second slide block is located on the second slide rail. The bottom end of the support frame is fixed to the second slide block with bolts. The crystal growth mold is fixed on the support frame. The crystal growth mold is made of graphite and can be customized in different sizes according to production requirements to meet the installation requirements of the crystal seeds. The threaded sleeve is fixed to one end of the second slide rail with bolts. The lead screw is threadedly connected to the threaded sleeve, and one end of the lead screw is rotatably connected to the second slide block. By controlling and adjusting the lead screw, the second slide block is pushed closer to the first electric furnace, so that the crystal growth mold is aligned and connected to the inlet at the bottom of the first electric furnace, and then the contact gap between the crystal growth mold and the first electric furnace is sealed. The crystal growth mold is equipped with a cold water circulation pipeline and connected to an external cold water supply system, including an inlet pipe and an outlet pipe. Cooling water enters through the inlet pipe and returns through the outlet pipe.

[0011] The traction mechanism includes an installation platform, a first motor, a lead screw, an installation frame, an installation base, a moving roller, a fixed roller, an adjusting screw, a positioning screw, a second motor, a fixing screw, and a fixing arm. The support legs of the installation platform are equipped with first sliding blocks, which are slidably connected to a first slide rail. A cross arm is provided on one side of the installation platform. The lead screw is threadedly connected to the cross arm. The two ends of the lead screw are rotatably connected to a support arm and a fixing plate, respectively. The first motor is fixed to the fixing plate, and the shaft end of the first motor is fixedly connected to the end of the lead screw. The bottom of the installation frame is fixed to the installation platform by a positioning screw, and the height of the installation frame is adjusted by rotating the bolt on the adjusting positioning screw. A pair of installation frames are provided, and a fixing screw is used to connect the installation frames. The mounting is secured; the side wall of the mounting frame has a sliding groove; the mounting base has sliders at both ends and is located in the sliding groove; the through shafts at both ends of the moving roller are rotatably connected to the mounting base located above; the through shafts at both ends of the fixed roller are rotatably connected to the mounting base located below; the adjusting screw is threadedly connected to the fixed arm at the top of the mounting frame, the fixed arm is bolted to the top of the mounting frame, and one end of the adjusting screw is rotatably connected to the mounting base located above; the second motor is fixed on the mounting base located above, and the shaft end of the second motor is fixedly connected to the through shaft at one end of the moving roller to drive the moving roller to rotate; furthermore, in order to improve the stability of the transmission and traction, a second motor can also be set on the mounting base located below, and drive the fixed roller to rotate simultaneously.

[0012] Furthermore, the mounting platform of the pulling mechanism is higher than the threaded sleeve in the positioning mechanism, which allows the pulling mechanism to slide closer to the crystal growth mold and not be interfered with by the positioning mechanism.

[0013] S1: Equipment Preparation:

[0014] 1) Installation of crystal growth mold:

[0015] By rotating the lead screw in the positioning mechanism, the second slide block is controlled to move on the second slide rail, thereby controlling the support frame and the crystal growth mold to move slowly and stably to the outer wall of the first electric furnace; further, the tilt angle of the first electric furnace is controlled by the deceleration adjuster, so that the first electric furnace and the crystal growth mold can cooperate with each other to complete the docking and installation of the crystal growth mold and the inlet; then the joint between the two is sealed to prepare for crystal growth and seed installation. In this embodiment, the crystal growth mold is made of graphite material and can be customized according to production requirements, including seed size and seed shape;

[0016] 2) Seed crystal installation:

[0017] One end of the selected single crystal seed is installed on the crystal growth mold to act as a plug, sealing the molten outlet, i.e. the inlet at the bottom of the first motor. Then, the first motor controls the screw to rotate, driving the installation platform to slide along the first slide rail and approach the crystal growth mold. The adjusting bolt controls the moving roller to rise so that the moving roller and the fixed roller clamp the other end of the crystal seed; prepare for pulling.

[0018] S2: Quartz sand molten soup:

[0019] Quartz sand is poured into the second electric furnace, and then the second electric furnace is powered on to heat the quartz sand to a molten state.

[0020] The melting temperature is 1780±10℃; preferably 1780℃.

[0021] The specific heating process:

[0022] At room temperature -573℃, heating time is 55-110 minutes to achieve uniform preheating; hold at 573℃ for 30-60 minutes to prevent sudden volume change and cracking; medium-speed heating.

[0023] 573-870℃, heating time 30-60min, medium-speed heating;

[0024] Heating temperature: 870-1470℃, heating time: 60-120 min, holding temperature at 1470℃ for 0-30 min; medium-speed heating.

[0025] Heat at 1470-1713℃ for 30-80 minutes, as this is close to the melting point, so slow down the temperature rise; hold at 1713℃ for 30-60 minutes to achieve complete melting and eliminate unmelted particles;

[0026] 1713℃-1780℃, heating time 10-20min, slow heating, melt the liquid and keep it warm, remove air bubbles;

[0027] S3: Preheating of the first electric furnace:

[0028] The preheating temperature is 1750±10℃. This step is optional and will not affect the crystal growth quality.

[0029] S4: Molten Transfer:

[0030] The molten metal in the second electric furnace is poured and transferred to the first electric furnace. The heating temperature in the first electric furnace is then raised to 1780±10℃ and maintained for a long time to achieve a heat preservation effect, so that the seed crystals and the molten metal can be fused together to achieve the seed crystal tip crystallization process.

[0031] S5: Seed growth, accompanied by cooling of the crystal growth mold by cold water circulation.

[0032] 1) Crystal seeding; First, turn on the cold water circulation pipe on the crystal growth mold and maintain the cold water circulation process. The cold water temperature is 20-28℃; allow the end of the crystal seed to cool and solidify at the fusion point of the molten metal to complete the crystal seeding.

[0033] 2) First stage crystal growth;

[0034] The first motor drives the entire installation platform to slide and reset, thus achieving the first stage of crystal growth by pulling.

[0035] 3) Second stage crystal growth;

[0036] Based on actual work requirements, the second stage of crystal growth is initiated. The second motor drives the moving roller to rotate, which in turn rotates together with the fixed roller to pull the clamped crystal, thus enabling continuous crystal growth and ultimately achieving a continuous crystal growth process for large-size single crystals.

[0037] S6: Meltwater replenishment;

[0038] When the molten material in the first electric furnace decreases or becomes insufficient, the molten material in the second electric furnace is poured in to replenish it. Depending on production requirements, such as the requirements for mass production, the second electric furnace can be kept in a state of continuous molten material, replenishing the molten material reserves in the first electric furnace at any time, thus making full preparations for continuous single crystal growth.

[0039] The advantages of this invention compared to existing technologies are as follows:

[0040] In this technical solution and implementation process, the concept of continuous steel casting, physical crystal growth method, and semiconductor Czochralski crystal growth technology are adopted to form a continuous and uninterrupted single crystal growth process. Its lateral single crystal growth concept breaks the traditional thinking of the original vertical Czochralski method, which can greatly improve the production capacity and realize the continuous growth of single crystals. It directly changes the shortcomings of existing single crystal production technologies, which are all batch-based and costly. Furthermore, by continuously growing single crystals and purifying quartz materials, production costs are reduced.

[0041] Furthermore, the raw material supply method of using a first electric furnace for heat preservation and a second electric furnace for molten metal replenishment provides the necessary technical support for continuous crystal growth. This ensures a sufficient supply of raw materials and molten quartz sand for crystal growth, enabling continuous crystal growth. During the crystal growth process, the crystal growth mold is made of graphite material, which is easy to replace. At the same time, the crystal growth mold is equipped with a cold water circulation pipeline to continuously circulate cold water and cool the molten metal, which promotes the conditions and environment for single crystal growth. Thus, under the premise of cooling with cold water and continuous replenishment of molten metal, the continuous growth of large-size single crystals is finally achieved.

[0042] The combined use of moving and stationary rollers in the traction mechanism ensures the stable and continuous growth of single crystals. Attached Figure Description

[0043] Appendix Figure 1 This is a schematic diagram of the structure of a large-size continuous single crystal growth device according to the present invention. Figure 1 ;

[0044] Appendix Figure 2 This is a schematic diagram of the structure of a large-size continuous single crystal growth device according to the present invention. Figure 2 ;

[0045] Appendix Figure 3 This is a schematic diagram of the traction mechanism. Figure 1 ;

[0046] Appendix Figure 4 This is a schematic diagram of the traction mechanism. Figure 2 ;

[0047] In the diagram: 1. Frame; 11. First slide rail; 12. Fixing plate; 2. First electric furnace; 3. Second electric furnace;

[0048] 4. Pulling mechanism; 41. Mounting platform; 411. First slide block; 412. Cross arm; 42. First motor; 43. Lead screw; 44. Mounting bracket; 441. Slide groove; 45. Mounting seat; 46. Moving roller; 47. Fixed roller; 48. Adjusting screw; 49. Positioning screw; 410. Second motor; 420. Fixing screw; 430. Fixing arm;

[0049] 5. Positioning mechanism; 51. Support platform; 52. Support arm; 53. Second slide rail; 54. Support frame; 55. Crystal growth mold; 551. Water inlet pipe; 552. Water outlet pipe; 56. Second slide block; 57. Threaded sleeve; 58. Lead screw; 6. Speed ​​reducer; 7. Crystal. Detailed Implementation

[0050] To facilitate understanding by those skilled in the art, the following is a detailed explanation in conjunction with the appendix. Figure 1-4 The technical solution of the present invention will be further described in detail below.

[0051] Example 1:

[0052] A large-size continuous single crystal growth apparatus includes a frame 1, a first electric furnace 2, a second electric furnace 3, a pulling mechanism 4, and a positioning mechanism 5. The frame 1 supports the first electric furnace 2, the second electric furnace 3, the pulling mechanism 4, and the positioning mechanism 5. The second electric furnace 3 is located diagonally above the first electric furnace 2 to replenish the molten metal in the first electric furnace 2. The positioning mechanism 5 is located between the first electric furnace 2 and the pulling mechanism 4, with one end of the positioning mechanism 5 positioned and connected to the first electric furnace 2. The pulling mechanism 4 is located at one end of the frame 1 and slidably connected to the frame 1. The first electric furnace 2 and the second electric furnace 3 electrically melt quartz sand. The first electric furnace 2 keeps the molten metal warm. The positioning mechanism 5 is positioned and installed between the first electric furnace 2. The seed crystal is placed in the positioning mechanism 5, and then the pulling mechanism 4 pulls the seed crystal to achieve the crystal growth process.

[0053] One end of the frame 1 is provided with a fixed plate 12 and a first slide rail 11, which is used to guide the sliding of the traction mechanism 4.

[0054] The first electric furnace 2 and the second electric furnace 3 are rotatably connected to the frame 1 on both sides of the furnace body; one side is provided with a speed reducer 6 for adjusting and controlling the tilt angle of the furnace body. This is the existing technology for electric furnace control and adjustment. The electric furnace is a conventional medium frequency electric furnace, which will not be described in detail. The bottom side wall of the first electric furnace 2 is provided with a flow outlet for drawing out molten quartz sand.

[0055] The positioning mechanism 5 includes a support platform 51, a support arm 52, a second slide rail 53, a support frame 54, a crystal growth mold 55, a second slide block 56, a threaded sleeve 57, and a lead screw 58. The support arm 52 is fixedly connected to the frame 1, the support platform 51 is fixed on the support arm 52, and the second slide rail 53 is fixed on the support platform 51. The second slide block 56 is disposed on the second slide rail 53. The bottom end of the support frame 54 is fixed to the second slide block 56 by bolts. The crystal growth mold 55 is fixed on the support frame 54. The crystal growth mold 55 is made of graphite and can be customized in different sizes according to production requirements to meet the installation requirements of the crystal seed. The threaded sleeve 57 is fixed to one end of the second slide rail 53 by bolts; the lead screw 58 is threadedly connected to the threaded sleeve 57, and one end of the lead screw 58 is rotatably connected to the second slide block 56; the second slide block 56 is pushed closer to the first electric furnace 2 by the control and adjustment of the lead screw 58, so that the crystal growth mold 55 is aligned and connected to the inlet at the bottom of the first electric furnace 2, and then the contact gap between the crystal growth mold 55 and the first electric furnace 2 is sealed; the crystal growth mold 55 is provided with a cold water circulation pipe and connected to an external cold water supply system, including an inlet pipe 551 and an outlet pipe 552, through which cooling water enters and the outlet pipe 552 returns the cooling water.

[0056] The pulling mechanism 4 includes an installation platform 41, a first motor 42, a lead screw 43, an installation frame 44, an installation base 45, a moving roller 46, a fixed roller 47, an adjusting screw 48, a positioning screw 49, a second motor 410, a fixing screw 420, and a fixing arm 430. The support legs of the installation platform 41 are provided with a first slide block 411, which is slidably connected to a first slide rail 11. A cross arm 412 is provided on one side of the installation platform 41. The lead screw 43 is threadedly connected to the cross arm 412. The two ends of the lead screw 43 are rotatably connected to a support arm 52 and a fixing plate 12, respectively. The first motor 42 is fixed to the fixing plate 12, and the shaft end of the first motor 42 is fixedly connected to the end of the lead screw 43. The bottom of the installation frame 44 is fixed to the installation platform 41 by a positioning screw 49, and the height of the installation frame 44 is adjusted by rotating the bolt on the adjusting positioning screw 49. The installation frame 44 has a pair of... The fixed screw 420 secures the mounting brackets 44; the mounting brackets 44 have a sliding groove 441 on their side walls; the mounting base 45 has sliders at both ends and is located in the sliding groove 441; the through shafts at both ends of the moving roller 46 are rotatably connected to the upper mounting base 45; the through shafts at both ends of the fixed roller 47 are rotatably connected to the lower mounting base 45; the adjusting screw 48 is threaded to the fixed arm at the top of the mounting bracket 44, the fixed arm 430 is bolted to the top of the mounting bracket 44, and one end of the adjusting screw 48 is rotatably connected to the upper mounting base 45; the second motor 410 is fixed on the upper mounting base 45, and the shaft end of the second motor 410 is fixedly connected to the through shaft at one end of the moving roller 46 to drive the moving roller 46 to rotate; furthermore, to improve the stability of the transmission and pulling, the second motor 410 can also be installed on the lower mounting base 45, and drive the fixed roller 47 to rotate simultaneously.

[0057] Furthermore, the mounting platform 41 of the pulling mechanism 4 is higher than the threaded sleeve 57 in the positioning mechanism 5, which allows the pulling mechanism 4 to slide closer to the crystal growth mold and not be interfered with by the positioning mechanism 5.

[0058] The specific application process is as follows:

[0059] The device is powered by an external power source and achieves coordinated operation between various mechanical components based on the existing PLC controller and the adapted control program and programming logic sequence.

[0060] This equipment is also equipped with mature control cabinet technology to control the stable pulling of the pulling mechanism 4. In addition, the first electric furnace 2 and the second electric furnace 3 are conventional medium-frequency electric furnaces, which are mature existing technologies and will not be described in detail. Before the crystal growth operation, the various equipment are assembled. First, the crystal growth mold 55 in the positioning mechanism 5 is connected and sealed with the inlet at the bottom of the first electric furnace 2. Specifically, the second slide 56, the support frame 54 and the crystal growth mold 55 are slowly moved by rotating the lead screw 58 to achieve precise connection. At the same time, the tilt of the first electric furnace 2 is controlled by the speed reducer 6. The two work together to realize the installation and connection of the crystal growth mold 55. Then, preparations are made before the seed crystal pulling.

[0061] The first motor 42 in the pulling mechanism 4 drives the lead screw 43 to rotate, thereby controlling the installation platform 41 to slide along the first slide rail 11 and approach the crystal growth mold 55. At this time, one end of the seed crystal is inserted into the crystal growth mold 55 as a plug, and the other end is inserted between the fixed roller 47 and the moving roller 46 to prepare for clamping and pulling. Specifically, the adjusting screw 48 controls the moving roller 46 to rise along the slide groove 441 and clamp one end of the seed crystal; then the quartz sand is melted.

[0062] Quartz sand is added to the second electric furnace 3 and heated to a molten state, while the first electric furnace 2 is preheated simultaneously. After preheating, the molten material in the second electric furnace 3 is poured into the first electric furnace 2, which is then kept at a constant temperature. Then, another batch of quartz sand is added to the second electric furnace 3 and heated to a molten state. During the crystal growth process, the first motor 42 drives the mounting platform 41 to slowly move and reset, performing the first stage of crystal growth. During crystal growth, the cold water circulation pipe in the crystal growth mold 55 continuously circulates to cool the molten material. When the pulling mechanism 4 moves to one end of the frame 1, the second motor 410 drives the moving roller 46 to rotate, which, in conjunction with the fixed roller 47, pulls the grown crystal 7 to achieve the second stage of crystal growth. When the first electric furnace 2 is empty or the molten material decreases, the molten material prepared in the second electric furnace 3 is poured into the first electric furnace 2 to replenish it, achieving a continuous crystal growth process. (See appendix) Figure 1 ,like Figure 2 (As shown).

[0063] A single crystal growth process for a large-size continuous single crystal growth apparatus, the specific steps of which are as follows:

[0064] S1: Equipment Preparation:

[0065] 1) Installation of crystal growth mold:

[0066] By rotating the lead screw in the positioning mechanism, the second slide block is controlled to move on the second slide rail, thereby controlling the support frame and the crystal growth mold to move slowly and stably to the outer wall of the first electric furnace; further, the tilt angle of the first electric furnace is controlled by the deceleration adjuster, so that the first electric furnace and the crystal growth mold can cooperate with each other to complete the docking and installation of the crystal growth mold and the inlet; then the joint between the two is sealed to prepare for crystal growth and seed installation. In this embodiment, the crystal growth mold is made of graphite material and can be customized according to production requirements, including seed size and seed shape;

[0067] 2) Seed crystal installation:

[0068] One end of the selected single crystal seed is installed on the crystal growth mold to act as a plug, sealing the molten outlet, i.e. the inlet at the bottom of the first motor. Then, the first motor controls the screw to rotate, driving the installation platform to slide along the first slide rail and approach the crystal growth mold. The adjusting bolt controls the moving roller to rise so that the moving roller and the fixed roller clamp the other end of the crystal seed; prepare for pulling.

[0069] S2: Quartz sand molten soup:

[0070] Quartz sand is poured into the second electric furnace, and then the second electric furnace is powered on to heat the quartz sand to a molten state.

[0071] The melting temperature is 1780℃;

[0072] The specific heating process:

[0073] At room temperature -573℃, heating time 80min to achieve uniform preheating; hold at 573℃ for 50min to prevent sudden volume change and cracking; medium-speed heating;

[0074] 573-870℃, heating time 50min, medium-speed heating;

[0075] Heating temperature: 870-1470℃, heating time: 100 min, then holding at 1470℃ for 20 min; medium-speed heating.

[0076] Heat at 1470-1713℃ for 60 minutes, as this is close to the melting point, so slow down the temperature rise; hold at 1713℃ for 50 minutes to achieve complete melting and eliminate unmelted particles;

[0077] 1713℃-1780℃, heating time 15min, slow heating, melting and holding the liquid, and removing air bubbles;

[0078] S3: Preheating of the first electric furnace:

[0079] The preheating temperature is 1750℃. This step is optional and will not affect the quality of crystal growth.

[0080] S4: Molten Transfer:

[0081] The molten metal in the second electric furnace is poured and transferred to the first electric furnace. The heating temperature in the first electric furnace is then increased to 1780°C and maintained for a long time to achieve a heat preservation effect, so that the seed crystals and the molten metal can be fused together to achieve the seed crystal tip crystallization process.

[0082] S5: Seed growth, accompanied by cooling of the crystal growth mold by cold water circulation.

[0083] 1) Crystal introduction; First, turn on the cold water circulation pipe on the crystal growth mold and maintain the cold water circulation process. The cold water temperature is 25℃; allow the end of the crystal seed to cool and solidify at the fusion point of the molten metal to complete the crystal introduction.

[0084] 2) First stage crystal growth;

[0085] The first motor drives the entire installation platform to slide and reset, thus achieving the first stage of crystal growth by pulling.

[0086] 3) Second stage crystal growth;

[0087] Based on actual work requirements, the second stage of crystal growth is initiated. The second motor drives the moving roller to rotate, which in turn rotates together with the fixed roller to pull the clamped crystal, thus enabling continuous crystal growth and ultimately achieving a continuous crystal growth process for large-size single crystals.

[0088] S6: Meltwater replenishment;

[0089] When the molten material in the first electric furnace decreases or becomes insufficient, the molten material in the second electric furnace is poured in to replenish it. Depending on production requirements, such as the requirements for mass production, the second electric furnace can be kept in a state of continuous molten material, replenishing the molten material reserves in the first electric furnace at any time, thus making full preparations for continuous single crystal growth.

[0090] Example 2: The difference from Example 1 is that:

[0091] Step S2: Quartz sand molten solution:

[0092] Quartz sand is poured into the second electric furnace, and then the second electric furnace is powered on to heat the quartz sand to a molten state.

[0093] The specific process:

[0094] The melting temperature is 1770℃;

[0095] The specific heating process:

[0096] At room temperature -573℃, heating time is 60 minutes to achieve uniform preheating; 573℃ is held for 40 minutes to prevent sudden volume change and cracking; medium-speed heating;

[0097] 573-870℃, heating time 40 minutes, medium-speed heating;

[0098] Heating temperature: 870-1470℃, heating time: 80 min, holding temperature at 1470℃ for 15 min; medium-speed heating.

[0099] Heat at 1470-1713℃ for 45 minutes, as this is close to the melting point, so slow down the temperature rise; hold at 1713℃ for 40 minutes to achieve complete melting and eliminate unmelted particles;

[0100] 1713℃-1780℃, heating time 10min, slow heating, melting and heat preservation, and degassing.

[0101] Example 3: The difference from Example 1 is that:

[0102] Step S2: Quartz sand molten solution:

[0103] Quartz sand is poured into the second electric furnace, and then the second electric furnace is powered on to heat the quartz sand to a molten state.

[0104] The specific process:

[0105] The melting temperature is 1775℃;

[0106] The specific heating process:

[0107] At room temperature -573℃, heating time is 105 minutes to achieve uniform preheating; 573℃ is held for 55 minutes to prevent sudden volume change and cracking; medium-speed heating;

[0108] 573-870℃, heating time 55min, medium-speed heating;

[0109] Heating temperature: 870-1470℃, heating time: 110 min, holding temperature at 1470℃ for 25 min; medium-speed heating.

[0110] Heat at 1470-1713℃ for 75 minutes, as this is close to the melting point, so slow down the temperature rise; hold at 1713℃ for 55 minutes to achieve complete melting and eliminate unmelted particles;

[0111] 1713℃-1780℃, heating time 20min, slow heating, melting and heat preservation, and degassing.

[0112] In the description of this invention, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," "outer," "front end," "rear end," "head," "tail," etc., 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 the invention 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 the invention. Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0113] In the description of this invention, the connection methods are divided into fixed connection and movable connection. Fixed connection methods include, but are not limited to, welding and bolting. Movable connection methods include, but are not limited to, sliding connection, rotating connection, and threaded connection. The connection method to achieve the desired effect should be selected according to the application of the solution. Washers are provided in the connection process of the bolts, fixing bolts, studs and nuts. At the same time, the connection of the bolts, fixing bolts, studs and nuts is fixed by thread locking.

[0114] In summary, the electronic or electrical components, including but not limited to motors and controllers, are existing components that are custom-made or purchased. The electrical connections between these components are conventional electric furnace connections or electrical connections found in the prior art, and are not within the scope of protection of this invention. The coordinated operation between these components is achieved based on existing controllers and adapted control programs and programming logic sequences. The aforementioned control programs are not within the scope of protection of this invention.

[0115] In summary, including but not limited to motors, controllers, and other power systems, as well as the transmission systems output by their respective power systems, protective covers should be provided according to the actual installation location if necessary, and sealing rings should be provided at the relative rotating connections to prevent wear or damage to the power system and transmission system caused by the external environment, and to further ensure the normal operation of the power system and transmission system.

[0116] The "automation" created by this invention does not rely on sensors, but is based on mechanical timing or stroke control. The actions of each mechanism can be automatically executed by the programmable controller and programming logic in a pre-set time sequence. Those skilled in the art know that this control method based on timing and stroke position switches is a mature automation technology, and the automated operation created by this invention can be achieved without sensors.

[0117] The above description is merely an example and illustration of the structure of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the structure of the invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

Claims

1. A large-size continuous single crystal growth apparatus, comprising a frame, a first electric furnace, a second electric furnace, a pulling mechanism, and a positioning mechanism, characterized in that... The frame supports a first electric furnace, a second electric furnace, a pulling mechanism, and a positioning mechanism. The second electric furnace is positioned diagonally above the first electric furnace to replenish the molten metal in the first furnace. The positioning mechanism is located between the first electric furnace and the pulling mechanism, with one end of the positioning mechanism positioned and connected to the first electric furnace. The pulling mechanism is located at one end of the frame and slidably connected to the frame. The first and second electric furnaces electrically melt quartz sand. The first electric furnace keeps the molten metal warm. The positioning mechanism is positioned and installed between the first electric furnace and the first electric furnace. The seed crystal is placed in the positioning mechanism, and then the pulling mechanism pulls the seed crystal to achieve crystal growth. One end of the frame is provided with a fixed plate and a first slide rail, which is used to guide the sliding of the traction mechanism. The first and second electric furnaces are rotatably connected to the frame on both sides of the furnace body; one side is provided with a speed reducer to adjust and control the tilt angle of the furnace body, and the bottom side wall of the first electric furnace is provided with a drain port to drain the molten quartz sand.

2. The large-size continuous single crystal growth apparatus according to claim 1, characterized in that... The positioning mechanism includes a support platform, a support arm, a second slide rail, a support frame, a crystal growth mold, a second slide block, a threaded sleeve, and a lead screw. The support arm is fixedly connected to the frame, the support platform is fixed on the support arm, and the second slide rail is fixed on the support platform. The second slide block is located on the second slide rail. The bottom end of the support frame is fixed to the second slide block with bolts. The crystal growth mold is fixed on the support frame. The crystal growth mold is made of graphite and can be customized in different sizes according to production requirements to meet the installation requirements of the crystal seeds. The threaded sleeve is fixed to one end of the second slide rail with bolts. The lead screw is threadedly connected to the threaded sleeve, and one end of the lead screw is rotatably connected to the second slide block. By controlling and adjusting the lead screw, the second slide block is pushed closer to the first electric furnace, so that the crystal growth mold is aligned and connected to the inlet at the bottom of the first electric furnace, and then the contact gap between the crystal growth mold and the first electric furnace is sealed. The crystal growth mold is equipped with a cold water circulation pipeline and connected to an external cold water supply system, including an inlet pipe and an outlet pipe. Cooling water enters through the inlet pipe and returns through the outlet pipe.

3. The large-size continuous single crystal growth apparatus according to claim 1, characterized in that... The traction mechanism includes an installation platform, a first motor, a lead screw, an installation frame, an installation base, a moving roller, a fixed roller, an adjusting screw, a positioning screw, a second motor, a fixing screw, and a fixing arm. The support legs of the installation platform are equipped with first sliding blocks, which are slidably connected to a first slide rail. A cross arm is provided on one side of the installation platform. The lead screw is threadedly connected to the cross arm. The two ends of the lead screw are rotatably connected to a support arm and a fixing plate, respectively. The first motor is fixed to the fixing plate, and the shaft end of the first motor is fixedly connected to the end of the lead screw. The bottom of the installation frame is fixed to the installation platform by a positioning screw, and the height of the installation frame is adjusted by rotating the bolt on the adjusting positioning screw. A pair of installation frames are provided, and a fixing screw is used to connect the installation frames. The mounting is secured; the side wall of the mounting frame has a sliding groove; the mounting base has sliders at both ends and is located in the sliding groove; the through shafts at both ends of the moving roller are rotatably connected to the mounting base located above; the through shafts at both ends of the fixed roller are rotatably connected to the mounting base located below; the adjusting screw is threadedly connected to the fixed arm at the top of the mounting frame, the fixed arm is bolted to the top of the mounting frame, and one end of the adjusting screw is rotatably connected to the mounting base located above; the second motor is fixed on the mounting base located above, and the shaft end of the second motor is fixedly connected to the through shaft at one end of the moving roller to drive the moving roller to rotate; furthermore, in order to improve the stability of the transmission and traction, a second motor can also be set on the mounting base located below, and drive the fixed roller to rotate simultaneously.

4. A large-size continuous single crystal growth apparatus according to claim 3, characterized in that... The mounting platform of the pulling mechanism is higher than the threaded sleeve in the positioning mechanism, which allows the pulling mechanism to slide closer to the crystal growth mold and not be interfered with by the positioning mechanism.

5. A large-size continuous single crystal growth apparatus according to claim 1, characterized in that... The specific steps of the single crystal growth process are as follows: S1: Equipment Preparation: 1) Installation of crystal growth mold: By rotating the lead screw in the positioning mechanism, the second slide block is controlled to move on the second slide rail, thereby controlling the support frame and the crystal growth mold to move slowly and stably to the outer wall of the first electric furnace; further, the tilt angle of the first electric furnace is controlled by the deceleration regulator, so that the first electric furnace and the crystal growth mold can cooperate with each other to complete the docking and installation of the crystal growth mold and the inlet; then the joint between the two is sealed to prepare for crystal growth and seed installation. In this embodiment, the crystal growth mold is made of graphite material and can be customized according to production requirements, including seed size and seed shape; 2) Seed crystal installation: One end of the selected single crystal seed is installed on the crystal growth mold to act as a plug, sealing the molten outlet, i.e. the inlet at the bottom of the first motor. Then, the first motor controls the screw to rotate, driving the installation platform to slide along the first slide rail and approach the crystal growth mold. The adjusting bolt controls the moving roller to rise so that the moving roller and the fixed roller clamp the other end of the crystal seed; prepare for pulling. S2: Quartz sand molten soup: Quartz sand is poured into the second electric furnace, and then the second electric furnace is powered on to heat the quartz sand to a molten state; the molten state temperature is 1780±10℃. S3: Preheating of the first electric furnace: The preheating temperature is 1750±10℃; S4: Molten Transfer: The molten metal in the second electric furnace is poured and transferred to the first electric furnace. The heating temperature in the first electric furnace is then raised to 1780±10℃ and maintained for a long time to achieve a heat preservation effect, so that the seed crystals and the molten metal can be fused together to achieve the seed crystal tip crystallization process. S5: Seed growth, accompanied by cooling of the crystal growth mold by cold water circulation. 1) Crystal seeding; First, turn on the cold water circulation pipe on the crystal growth mold and maintain the cold water circulation process. The cold water temperature is 20-28℃; allow the end of the crystal seed to cool and solidify at the fusion point of the molten metal to complete the crystal seeding. 2) First stage crystal growth; The first motor drives the entire installation platform to slide and reset, thus achieving the first stage of crystal growth by pulling. 3) Second stage crystal growth; Based on actual work requirements, the second stage of crystal growth is initiated. The second motor drives the moving roller to rotate, which in turn rotates together with the fixed roller to pull the clamped crystal, thus enabling continuous crystal growth and ultimately achieving a continuous crystal growth process for large-size single crystals. S6: Meltwater replenishment; When the molten material in the first electric furnace decreases or becomes insufficient, the molten material in the second electric furnace is poured in to replenish it. Depending on production requirements, such as the requirements for mass production, the second electric furnace can be kept in a state of continuous molten material, replenishing the molten material reserves in the first electric furnace at any time, thus making full preparations for continuous single crystal growth.

6. A large-size continuous single crystal growth apparatus according to claim 5, characterized in that... In step S2: the specific heating process: At room temperature -573℃, heating time is 55-110 minutes to achieve uniform preheating; hold at 573℃ for 30-60 minutes to prevent sudden volume change and cracking; medium-speed heating. 573-870℃, heating time 30-60min, medium-speed heating; Heating temperature: 870-1470℃, heating time: 60-120 min, holding temperature at 1470℃ for 0-30 min; medium-speed heating. Heat at 1470-1713℃ for 30-80 minutes, as this is close to the melting point, so slow down the temperature rise; hold at 1713℃ for 30-60 minutes to achieve complete melting and eliminate unmelted particles; Heat at 1713℃-1780℃ for 10-20 minutes, using a slow heating method to melt the liquid, maintain its temperature, and remove air bubbles.

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