A polycrystalline silicon directional solidification impurity removal and ingot casting process
By designing a polycrystalline silicon directional solidification and decomposition and ingot casting process, using hydraulic cylinders, motors and water-cooled pipelines and other components, the directional solidification and efficient decomposition of polycrystalline silicon are achieved, solving the problems of heat dissipation and exhaust gas treatment in traditional equipment, and improving the yield and purity of the ingot.
Patent Information
- Application Number
- CN202411895012.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-21
- Publication Date
- 2025-04-01
- Estimated Expiration
- Not applicable · inactive patent
AI Technical Summary
The heat dissipation of traditional polysilicon ingot equipment during crystal growth is uneven, resulting in a concave growth interface and the inability to solidify polysilicon directionally, making it difficult to operate, and the exhaust gas is gathered inside the equipment and cannot be processed, which makes impurities easily diffuse.
A polycrystalline silicon directional solidification and impurity removal and ingot casting process is designed, using the device main body, support column, controller, motor, hydraulic cylinder, water-cooled pipeline and other components. Through the coordinated control of the hydraulic cylinder and motor, the crucible rise and the heating of silicon material are realized, and the water-cooled pipeline is used to achieve directional solidification, and exhaust gas is collected through the exhaust pipe to prevent impurities from spreading.
The purity of polycrystalline silicon and the quality of ingots are improved, the yield and production efficiency of polycrystalline silicon ingots are significantly improved, the problems of unbalanced heat dissipation and exhaust gas treatment are solved, and directional solidification and efficient decomposition are achieved.
Smart Images
Figure CN119736711A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of polysilicon manufacturing, and in particular relates to a polysilicon directional solidification impurity removal and ingot casting process. Background Art
[0002] The polysilicon directional solidification impurity removal and ingot casting equipment is a high-precision and high-efficiency manufacturing equipment designed specifically for the purification and ingot casting process of polysilicon materials. The equipment is mainly composed of key components such as a vacuum chamber, a heating system, a crucible, a directional solidification control mechanism and an impurity removal device. In the vacuum chamber, the polysilicon material is heated to a molten state through a precisely controlled heating system, and with the help of a directional solidification control mechanism, a stable temperature gradient is formed in the crucible, guiding the silicon liquid to solidify from the bottom and grow in a single direction. In addition, some equipment is also equipped with an impurity removal device, such as a vacuum tail extraction device, which can effectively remove impurity-rich areas in the silicon melt at the end of solidification and further improve the purity of the ingot. The entire equipment has a reasonable structural design and is easy to operate, which can effectively improve the yield and quality of polysilicon ingots.
[0003] In the process of implementing this application, it was found that the technology has the following problems: during the crystal growth process, the traditional polysilicon ingot casting equipment has uneven heat dissipation, which causes the growth interface to be concave. At the same time, it is impossible to directionally solidify the polysilicon, which makes the operation difficult. During the directional solidification process, the exhaust gas generated accumulates inside the equipment and cannot be processed, which easily causes impurities to diffuse.
[0004] Therefore, a polysilicon directional solidification impurity removal and ingot casting process is proposed. Summary of the invention
[0005] The purpose of the present invention is to improve the purity and ingot quality of polysilicon, timely collect the tail gas during the solidification process, and directionally solidify the polysilicon product. The present application provides a polysilicon directional solidification impurity removal and ingot casting process.
[0006] The technical solution adopted by the present invention is as follows: A polysilicon directional solidification impurity removal and ingot casting process, comprising a device body, four groups of support columns are symmetrically arranged on the bottom outer surface of the device body, a controller is arranged on the left outer surface of the device body, two groups of observation windows and support plates are arranged on the front and rear side outer surfaces of the device body, a hydraulic cylinder is arranged on the top outer surface of each group of support plates, and a hydraulic rod is arranged on the top outer surface of the hydraulic cylinder; A cover plate is provided on the top outer surface of the device body, motors are provided on the left and right sides of the cover plate, the top outer surface of each group of hydraulic rods is fixedly connected to the bottom surface of the cover plate, a temperature sensor is provided on the bottom outer surface of the cover plate, an exhaust gas collection box and an exhaust pipe are provided on the top outer surface of the cover plate, and the output end of the exhaust pipe is connected to the exhaust gas collection box.
[0007] Furthermore, a screw rod is provided at the output end of each group of the motors, a lifting chamber is provided on the periphery of each group of the screw rods, a rotating groove is provided on the bottom inner surface of the lifting chamber, and the other end of each group of the screw rods is rotatably connected to the inner surface of the corresponding rotating groove.
[0008] Furthermore, a plurality of cooling pipes are arranged in parallel at the bottom of the device body, an operating room is arranged between two groups of lifting chambers, movable grooves are provided between the left and right outer surfaces of the operating room and the corresponding lifting chambers, and a plurality of through holes are arranged between the bottom of the operating room and the cooling pipes.
[0009] Furthermore, the periphery of each group of the screw rods is rotatably connected with a threaded sleeve, and a group of connecting rods are provided on the outer surfaces of the two groups of the threaded sleeves on one side close to each other, and a crucible is provided on the outer surfaces of the other side of the two groups of the connecting rods, and a bottom graphite heater is provided at the bottom of the crucible.
[0010] Furthermore, a water cooling pipeline is arranged around the inside of the crucible, a pipeline water inlet is arranged at the bottom end of the water cooling pipeline, an argon box is connected to the left outer surface of the device body, and a vacuum pump is connected to the right outer surface of the device body.
[0011] Furthermore, side graphite heaters are provided on the left and right inner walls of the device body, and the bottom graphite heater, the side graphite heater and the controller are all electrically connected to an external power supply.
[0012] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: 1. In the present invention, when directional solidification impurity removal and ingot casting equipment is used to produce polysilicon, the controller controls the start and stop of the hydraulic cylinder and the heating of the side graphite heater through the controller, and the hydraulic rod connected to the output end thereof is longitudinally moved by starting the corresponding hydraulic cylinder to open the cover plate, and the screw connected to the output end thereof is rotated by starting the corresponding motor. Since the outer periphery of the motor is rotated and connected with a connecting rod, the rotation of the screw will drive the corresponding crucible to rise. After the processed silicon material is added into the crucible, the reverse motor and the hydraulic cylinder equipment are returned to the original state. First, the gas inside the device is extracted by an exhaust pump, and the preheating of the side graphite heater and the bottom graphite heater is controlled by the controller. The preheating temperature is between room temperature and 1200°C. After the preheating is completed, argon is filled into the device through an argon box to maintain the melting vacuum degree. The temperature inside the device body is monitored in real time by a temperature sensor, and the heating temperature of the side graphite heater and the bottom graphite heater is continuously increased to melt the silicon material inside the crucible to form a silicon melt.
[0013] 2. In the present invention, water-cooling liquid is gradually filled into the water-cooling pipeline through the water inlet of the pipeline. As the liquid column in the water-cooling pipeline gradually rises, the silicon liquid begins to solidify from the bottom and grows upward in a single direction to form a silicon ingot. During the directional solidification process, the exhaust gas generated is collected into the exhaust gas collection box through the exhaust pipe to prevent the diffusion of impurities. After solidification, the silicon ingot is annealed to eliminate internal stress. The side graphite heater and the bottom graphite heater are controlled by a controller to gradually reduce the heating power to cool the silicon ingot to room temperature or lower temperature. At the same time, the inside of the device is annealed by starting multiple groups of cooling tubes. Finally, the silicon ingot is taken out of the crucible to complete the entire ingot casting process. BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Figure 1 It is a schematic diagram of the overall structure of the present invention; Figure 2 It is a schematic diagram of the structure of the water cooling assembly of the present invention; Figure 3 It is a cross-sectional view of the overall structure of the present invention; Figure 4 For the present invention Figure 3 Detail of point A in the middle.
[0015] In the figure: 1-device body; 2-support column; 3-controller; 4-motor; 5-cover plate; 6-exhaust pipe; 7-observation window; 8-exhaust collection box; 9-hydraulic rod; 10-hydraulic cylinder; 11-support plate; 12-operating room; 13-argon box; 14-exhaust pump; 15-threaded sleeve; 16-side graphite heater; 17-bottom graphite heater; 18-lifting chamber; 19-crucible; 20-connecting rod; 21-movable groove; 22-screw rod; 23-rotating groove; 24-cooling pipe; 25-through hole; 26-water cooling pipeline; 27-pipeline water inlet; 28-temperature sensor. DETAILED DESCRIPTION
[0016] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Example
[0017] Reference Figure 1-Figure 4A polysilicon directional solidification impurity removal and ingot casting process includes a device body 1, four groups of support columns 2 are symmetrically arranged on the bottom outer surface of the device body 1, a controller 3 is arranged on the left outer surface of the device body 1, two groups of observation windows 7 and support plates 11 are arranged on the front and rear side outer surfaces of the device body 1, a hydraulic cylinder 10 is arranged on the top outer surface of each group of support plates 11, a hydraulic rod 9 is arranged on the top outer surface of the hydraulic cylinder 10, a cover plate 5 is arranged on the top outer surface of the device body 1, a motor 4 is arranged on the left and right sides of the cover plate 5, the top outer surface of each group of hydraulic rods 9 is fixedly connected to the bottom surface of the cover plate 5, a temperature sensor 28 is arranged on the bottom outer surface of the cover plate 5, an exhaust gas collection box 8 and an exhaust pipe 6 are arranged on the top outer surface of the cover plate 5, and the output end of the exhaust pipe 6 is connected to the exhaust gas collection box 8. Specifically, through the cooperation of the above structures, the purity of polysilicon and the quality of ingot casting can be effectively improved, and the yield rate and production efficiency of polysilicon ingot casting can be significantly improved.
[0018] Reference Figure 1-Figure 4 A screw rod 22 is provided at the output end of each group of motors 4, and a lifting chamber 18 is provided on the periphery of each group of screw rods 22. A rotating groove 23 is provided on the bottom inner surface of the lifting chamber 18, and the other end of each group of screw rods 22 is rotatably connected to the inner surface of the corresponding rotating groove 23. Specifically, the screw rod 22 connected to the output end of the corresponding motor 4 is rotated by starting the corresponding motor 4. A plurality of cooling tubes 24 are arranged in parallel at the bottom of the device body 1, an operating room 12 is arranged between the two lifting chambers 18, movable grooves 21 are provided between the left and right outer surfaces of the operating room 12 and the corresponding lifting chambers 18, and a plurality of through holes 25 are provided between the bottom of the operating room 12 and the cooling tubes 24. Specifically, after solidification is completed, the silicon ingot is annealed to eliminate internal stress, and the controller 3 controls the side graphite heater 16 and the bottom graphite heater 17 to gradually reduce the heating power to cool the silicon ingot to room temperature or lower temperature. At the same time, the inside of the device is annealed by starting multiple cooling tubes 24, and finally the silicon ingot is taken out of the crucible to complete the entire ingot casting process.
[0019] Reference Figure 1-Figure 4The periphery of each group of screw rods 22 is rotatably connected with a threaded sleeve 15, and a group of connecting rods 20 are provided on the outer surfaces of the two groups of threaded sleeves 15 that are close to each other. A crucible 19 is provided on the outer surfaces of the other sides of the two groups of connecting rods 20. A bottom graphite heater 17 is provided at the bottom of the crucible 19. Specifically, since the periphery of the motor 22 is rotatably connected with the connecting rod 20, the rotation of the screw rod 22 will drive the corresponding crucible 19 to rise. After preheating, the heating temperature of the side graphite heater 16 and the bottom graphite heater 17 will continue to increase, so that the silicon material inside the crucible 19 melts to form a silicon melt. A water cooling pipeline 26 is arranged around the inside of the crucible 19, and a pipeline water inlet 27 is arranged at the bottom end of the water cooling pipeline 26. The left outer surface of the device body 1 is connected to the argon box 13, and the right outer surface of the device body 1 is connected to the vacuum pump 14. Specifically, water cooling liquid is gradually filled into the water cooling pipeline 26 through the pipeline water inlet 27. As the liquid column in the water cooling pipeline 26 gradually rises, the silicon liquid begins to solidify from the bottom and grows upward in a single direction to form a silicon ingot. The gas inside the device is extracted by the vacuum pump 14, and the preheating of the side graphite heater 16 and the bottom graphite heater 17 is controlled by the controller 3. The preheating temperature is between room temperature and 1200°C. After the preheating is completed, argon is filled into the device through the argon box 13 to maintain the melting vacuum.
[0020] Reference Figure 1-Figure 4 , side graphite heaters 16 are provided on the left and right inner walls of the device body 1, and the bottom graphite heater 17, the side graphite heater 16 and the controller 3 are electrically connected to the external power supply. Specifically, the start and stop of the hydraulic cylinder 10 and the heating of the side graphite heater 16 are controlled by the controller 3.
[0021] The implementation principle of a polysilicon directional solidification impurity removal and ingot casting process embodiment of the present application is: When the directional solidification impurity removal and ingot casting equipment is used to produce polysilicon, the controller 3 adopts the ATC89C52 single chip microcomputer, and controls the start and stop of the hydraulic cylinder 10 and the heating of the side graphite heater 16 through the controller 3. By starting the corresponding hydraulic cylinder 10, the hydraulic rod 9 connected to the output end is moved longitudinally, so as to open the cover plate 5. By starting the corresponding motor 4, the screw rod 22 connected to the output end is rotated. Since the outer peripheral rotation of the motor 22 is connected to the connecting rod 20, the rotation of the screw rod 22 will drive the corresponding crucible 19 to rise. After the processed silicon material is added into the crucible 19, The reversing motor 4 and the hydraulic cylinder 10 equipment return to the original state. First, the gas inside the device is extracted by the vacuum pump 14, and the preheating of the side graphite heater 16 and the bottom graphite heater 17 is controlled by the controller 3. The preheating temperature is between room temperature and 1200°C. After the preheating is completed, argon is filled into the device through the argon box 13 to maintain the melting vacuum degree. The temperature inside the device body 1 is monitored in real time by the temperature sensor 28, and the heating temperature of the side graphite heater 16 and the bottom graphite heater 17 is continuously increased to melt the silicon material inside the crucible 19 to form a silicon melt.
[0022] On the other hand, water-cooling liquid is gradually filled into the water-cooling pipeline 26 through the pipeline water inlet 27. As the liquid column in the water-cooling pipeline 26 gradually rises, the silicon liquid begins to solidify from the bottom and grows upward in a single direction to form a silicon ingot. During the directional solidification process, the exhaust gas generated is collected into the exhaust gas collection box 8 through the exhaust pipe 6 to prevent the diffusion of impurities. After solidification, the silicon ingot is annealed to eliminate internal stress. The controller 3 controls the side graphite heater 16 and the bottom graphite heater 17 to gradually reduce the heating power to cool the silicon ingot to room temperature or lower temperature. At the same time, the inside of the device is annealed by starting multiple groups of cooling tubes 24. Finally, the silicon ingot is taken out of the crucible to complete the entire ingot casting process.
[0023] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims
1. A polycrystalline silicon directional solidification impurity removal and ingot casting process, comprising a device body (1), characterized in that: Four groups of support columns (2) are symmetrically arranged on the bottom outer surface of the device body (1); a controller (3) is arranged on the left outer surface of the device body (1); two groups of observation windows (7) and support plates (11) are arranged on the front and rear side outer surfaces of the device body (1); a hydraulic cylinder (10) is arranged on the top outer surface of each group of support plates (11); and a hydraulic rod (9) is arranged on the top outer surface of each group of hydraulic cylinders (10); The top outer surface of the device body (1) is provided with a cover plate (5), and motors (4) are provided on both left and right sides of the cover plate (5). The top outer surface of each group of hydraulic rods (9) is fixedly connected to the bottom surface of the cover plate (5), and a temperature sensor (28) is provided on the bottom outer surface of the cover plate (5). The top outer surface of the cover plate (5) is provided with an exhaust gas collection box (8) and an exhaust pipe (6), and the output end of the exhaust pipe (6) is connected to the exhaust gas collection box (8).
2. A polycrystalline silicon directional solidification impurity removal and ingot casting process as claimed in claim 1, characterized in that: The output end of each group of the motors (4) is provided with a screw rod (22), the periphery of each group of the screw rods (22) is provided with a lifting chamber (18), the bottom inner surface of the lifting chamber (18) is provided with a rotation groove (23), and the other end of each group of the screw rods (22) is rotatably connected to the inner surface of the corresponding rotation groove (23).
3. A polycrystalline silicon directional solidification impurity removal and ingot casting process as claimed in claim 2, characterized in that: A plurality of groups of cooling pipes (24) are arranged in parallel at the bottom of the device body (1); an operating room (12) is arranged between the cooling pipes (24) and two groups of lifting chambers (18); movable grooves (21) are provided between the left and right outer surfaces of the operating room (12) and the corresponding lifting chambers (18); and a plurality of groups of through holes (25) are provided between the bottom of the operating room (12) and the cooling pipes (24).
4. A polycrystalline silicon directional solidification impurity removal and ingot casting process as claimed in claim 2, characterized in that: The periphery of each group of the screw rods (22) is rotatably connected to a threaded sleeve (15), and a group of connecting rods (20) are provided on the outer surfaces of the two groups of the threaded sleeves (15) on one side close to each other, and a crucible (19) is provided on the outer surfaces of the other side of the two groups of the connecting rods (20), and a bottom graphite heater (17) is provided at the bottom of the crucible (19).
5. A polysilicon directional solidification impurity removal and ingot casting process as claimed in claim 4, characterized in that: A water cooling pipeline (26) is arranged around the inside of the crucible (19), and a pipeline water inlet (27) is arranged at the bottom end of the water cooling pipeline (26). The left outer surface of the device body (1) is connected to an argon box (13), and the right outer surface of the device body (1) is connected to a vacuum pump (14).
6. A polycrystalline silicon directional solidification impurity removal and ingot casting process as claimed in claim 4, characterized in that: Side graphite heaters (16) are provided on the left and right inner walls of the device body (1), and the bottom graphite heater (17), the side graphite heaters (16) and the controller (3) are all electrically connected to an external power supply.