A novel silicon core structure, silicon core assembly, and reduction furnace structure
By optimizing the silicon core structure and the inner wall material of the reduction furnace, the problems of abnormality at the top of the silicon core and heat loss were solved, thus achieving stability and quality improvement in polycrystalline silicon production.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SICHUAN YONGXIANG CO LTD
- Filing Date
- 2025-06-26
- Publication Date
- 2026-06-23
AI Technical Summary
In current polysilicon production, abnormal phenomena such as molten silicon and black inclusions are prone to occur at the top of the silicon core. Furthermore, the lack of improvement in the material of the inner wall of the reduction furnace leads to heat loss and uneven gas distribution, affecting production quality and stability.
It adopts an integral tapered or stepped silicon core structure, combined with a bell jar design of Hastelloy C-22 or nickel-silver alloy and 316L material, to enhance the cooling channel and exhaust pipe structure and optimize the thermal field and current distribution.
It effectively avoids heat accumulation at the top of the silicon core, improves the silicon rod deposition rate and mechanical strength, enhances production stability and material utilization, reduces heat loss, and prevents silicon core detachment and abnormal phenomena.
Smart Images
Figure CN224398276U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of polycrystalline silicon production technology, and in particular to a novel silicon core structure, silicon core assembly, and reduction furnace structure. Background Technology
[0002] In existing technologies, the modified Siemens process is generally used for polycrystalline silicon production. The reduction process mainly involves the following steps: purified TCS is vaporized by steam heating and mixed with H2, then enters the bell-shaped reactor through a nozzle on the chassis for CVD reaction. During the reaction, the silicon core acts as the reaction carrier; current is transmitted to the silicon core through electrodes, generating heat for the reaction. Cooling is achieved through water circulation in the bell-shaped reactor and the chassis, which protects the equipment.
[0003] For example, in the prior art, Chinese utility model patent document with publication number CN207811279U and publication date September 4, 2018, discloses the following technical solution: A bell-shaped end cap, comprising an end cap body, the end cap body including an inner wall and an outer wall spaced apart, the inner side of the inner wall forming a first receiving cavity, and the cavity between the inner wall and the outer wall forming a first cooling channel; the end cap body having at least one exhaust port and at least one cooling medium outlet, the exhaust port communicating with the first receiving cavity, and the cooling medium outlet communicating with the first cooling channel. A bell-shaped jar, comprising a cover body and the aforementioned bell-shaped end cap, the cover body having a second receiving cavity inside, the second receiving cavity communicating with the first receiving cavity.
[0004] This technical solution does not improve the silicon core structure or the material of the inner wall of the reduction furnace. In the reduction process, commonly used silicon cores are cylindrical or cubical structures with identical dimensions at the top and bottom. Common reduction furnaces are bell-shaped structures with a single 316L inner wall. To reduce energy consumption, some sections of the inner wall are silver-coated. However, in actual production, due to the unique structure of the bell-shaped reduction furnace—where the reactant gas is injected from the bottom up and exits through the tail gas vent—the gas velocity gradually decreases from bottom to top, easily creating a gas dead zone at the top. The gas contacted by the top of the silicon core is the remaining gas from the lower reaction section. Furthermore, the bell-shaped structure of the reduction furnace results in significant heat accumulation in the top arc section, especially after silver coating of the inner wall, significantly increasing the temperature at the top of the silicon core. Combined with the complex gas composition at the top, this leads to poor appearance during growth, with the top silicon rod being looser and larger in diameter, making it prone to melting and furnace collapse.
[0005] As a result, the top silicon core is very prone to abnormalities such as molten silicon and blackening during the growth process. Summary of the Invention
[0006] To solve the above-mentioned technical problems, this utility model proposes a novel silicon core structure, silicon core assembly, and reduction furnace structure, which can effectively avoid abnormalities such as molten silicon and black inclusions in the silicon core during the growth process.
[0007] This utility model is achieved by adopting the following technical solution:
[0008] A novel silicon core structure, wherein the silicon core adopts an integral tapered structure or a stepped structure; the integral tapered structure specifically refers to the silicon core whose cross-sectional dimension continuously decreases along the axial direction from top to bottom; the stepped structure specifically refers to the silicon core comprising a first silicon core segment and a second silicon core segment connected sequentially from top to bottom, wherein the cross-sectional dimension of the first silicon core segment is larger than the cross-sectional dimension of the second silicon core segment.
[0009] The length ratio of the first silicon core segment to the second silicon core segment is (0.22~0.3):1; the maximum width of the first silicon core segment is 15 mm~25 mm, and the maximum width of the second silicon core segment is 5 mm less than the maximum width of the first silicon core segment.
[0010] When the silicon core adopts an integral tapered structure, the maximum width of the top of the silicon core is 15 mm to 25 mm, and the maximum width of the bottom of the silicon core is 5 mm smaller than the maximum width of the top.
[0011] A silicon core component comprising the aforementioned novel silicon core structure.
[0012] The silicon core is also provided with an overlap hole at the top.
[0013] It also includes a crossbeam, the two ends of which are respectively used to insert into the overlapping holes of two adjacent silicon cores.
[0014] A reduction furnace structure includes the aforementioned novel silicon core structure.
[0015] The reduction furnace structure also includes a bell jar, which comprises a connected cylindrical section and an arc section. The inner wall material of the cylindrical section is Hastelloy C-22 or nickel-silver alloy, and the inner wall material of the arc section is 316L.
[0016] The bell jar adopts a sandwich structure to form a cooling channel, which is connected to an inlet pipe and an outlet pipe, with the outlet pipe located at the top of the bell jar.
[0017] It also includes an exhaust pipe; the water outlet pipe is U-shaped and includes a straight section in the middle; one end of the exhaust pipe is connected to the top of the straight section, and the other end is set downward and has a valve at the end.
[0018] Compared with the prior art, the beneficial effects of this utility model are as follows:
[0019] 1. In this utility model, whether it is the overall tapered structure or the stepped structure of the new silicon core structure, when the silicon rod deposition rate is increased by supplementing the current in actual production, the heat generation at the top of the silicon core can be effectively reduced. This can effectively avoid abnormalities such as melting silicon and blackening during the growth process of the silicon core. At the same time, the surface area at the top of the silicon core is increased, which increases the contact area between the raw material gas and the silicon core and promotes the generation of CVD reaction at the top of the silicon core.
[0020] 2. By refining the dimensions of the silicon core, not only can the thermal field and current distribution be optimized, improving the crystal growth quality and process stability, but also the mechanical strength of the silicon core can be enhanced, improving material utilization and assembly convenience.
[0021] 3. When the beam structure is used in conjunction with silicon cores of the overall tapered structure or stepped structure, it can effectively avoid silicon core vibration caused by pressure testing in the reduction furnace and raw material gas deviation, and can avoid pressure testing failure caused by silicon core falling off, thereby reducing abnormalities during the operation of the reduction furnace.
[0022] 4. The bell jar comprises a connected cylindrical section and an arc-shaped section. For the first time, the inner walls of the cylindrical and arc-shaped sections are made of different materials, selected to address the different operating conditions of the upper and lower parts of the reduction furnace. Specifically, the inner wall material of the cylindrical section is Hastelloy C-22 or a nickel-silver alloy, which provides excellent resistance to pitting and crevice corrosion, making it suitable for harsh environments involving highly oxidizing acids and alkalis. It also provides good insulation against heat radiation, preventing heat loss during furnace operation. The inner wall material of the arc-shaped section is 316L, which meets the material characteristics required for polycrystalline silicon production. It is corrosion-resistant, high-temperature resistant, and pollution-free, while its heat-concentrating effect is weaker than Hastelloy C-22 or nickel-silver alloy. Through this combination, the high smoothness of Hastelloy C-22 effectively reduces heat loss during production, while preventing heat accumulation at the top from negatively impacting silicon rod growth.
[0023] 5. The cooling channel design effectively cools the bell jar, thereby improving its thermal control performance and operational stability.
[0024] 6. One end of the exhaust pipe is connected to the top of the straight section of the water outlet pipe. This connection effectively prevents cooling water in the cooling channel from flowing into the exhaust pipe during operation, thus preventing water vapor backflow or liquid residue from affecting the exhaust function. The other end of the exhaust pipe extends downwards and is equipped with a valve at its end, facilitating the operator's opening and closing control and maintenance of the exhaust pipe, improving operability and safety. Attached Figure Description
[0025] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments, wherein:
[0026] Figure 1This is a schematic diagram of the structure of this utility model;
[0027] Figure 2 This is a schematic diagram showing that the silicon core in this utility model has a stepped structure;
[0028] Figure 3 This is a schematic diagram of the silicon core in this utility model having an integral tapered structure;
[0029] Figure 4 This is a schematic diagram of the crossbeam structure in this utility model;
[0030] Marked in the image:
[0031] 1. Silicon core, 2. First silicon core segment, 3. Second silicon core segment, 4. Overlapping hole, 5. Crossbeam, 6. Bell jar, 7. Cylindrical segment, 8. Arc segment, 9. Cooling channel, 10. Water outlet pipe, 11. Exhaust pipe, 12. Straight segment, 13. Valve. Detailed Implementation
[0032] Example 1
[0033] As a basic embodiment of this utility model, the utility model includes a novel silicon core structure, wherein the silicon core 1 adopts an integral tapered structure or a stepped structure. Specifically, the integral tapered structure means that the cross-sectional dimension of the silicon core 1 continuously decreases along the axial direction from the top to the bottom. The stepped structure specifically means that, from the top to the bottom, the silicon core 1 includes a first silicon core segment 2 and a second silicon core segment 3 connected sequentially, wherein the cross-sectional dimension of the first silicon core segment 2 is larger than the cross-sectional dimension of the second silicon core segment 3.
[0034] Example 2
[0035] In a preferred embodiment of this utility model, the utility model includes a novel silicon core structure, wherein the silicon core 1 adopts an integral tapered structure or a stepped structure. Specifically, the integral tapered structure means that the cross-sectional dimension of the silicon core 1 continuously decreases axially from top to bottom. The stepped structure specifically means that, from top to bottom, the silicon core 1 includes a first silicon core segment 2 and a second silicon core segment 3 connected sequentially, wherein the cross-sectional dimension of the first silicon core segment 2 is larger than the cross-sectional dimension of the second silicon core segment 3.
[0036] Specifically, when silicon core 1 adopts a stepped structure, the length ratio of the first silicon core segment 2 to the second silicon core segment 3 is (0.22~0.3):1; the maximum width of the first silicon core segment 2 is 15 mm~25 mm, and the maximum width of the second silicon core segment 3 is 5 mm less than the maximum width of the first silicon core segment 2. When silicon core 1 adopts an integral tapered structure, the maximum width of the top of silicon core 1 is 15 mm~25 mm, and the maximum width of the bottom of silicon core 1 is 5 mm less than the maximum width of the top.
[0037] Example 3
[0038] In another preferred embodiment of this utility model, the utility model includes a novel silicon core structure, wherein the length L of the silicon core 1 is 2.6m ≤ L ≤ 3.3m, and the maximum width d is 15mm ≤ d ≤ 25mm. The silicon core 1 adopts an integral tapered structure or a stepped structure.
[0039] Among them, refer to the appendix of the instruction manual Figure 3 The overall tapered structure specifically refers to the fact that the cross-sectional dimensions of silicon core 1 continuously decrease along the axial direction from top to bottom. Specifically, the maximum width of the top of silicon core 1 is 15 mm to 25 mm, and the maximum width of the bottom of silicon core 1 is 5 mm smaller than the maximum width of the top.
[0040] Refer to the instruction manual appendix Figure 2 The stepped structure specifically refers to the following: from the top to the bottom of silicon core 1, silicon core 1 includes a first silicon core segment 2 and a second silicon core segment 3 connected sequentially. The cross-sectional dimension of the first silicon core segment 2 is larger than that of the second silicon core segment 3. Specifically, the length of the second silicon core segment 3 is 2 m to 2.7 m, and the length of the first silicon core segment 2 is 0.6 m. The sum of the lengths of the two segments is within the length L of the silicon core. Along the axial direction of silicon core 1, the length ratio of the first silicon core segment 2 to the second silicon core segment 3 is (0.22~0.3):1. The maximum width of the first silicon core segment 2 is 15 mm to 25 mm, and the maximum width of the second silicon core segment 3 is 5 mm less than the maximum width of the first silicon core segment 2.
[0041] The cross-section can be circular or square. When the cross-section is circular, the overall tapered silicon core 1 is frustum-shaped, and the stepped structure includes two connected cylinders. The maximum width of the silicon core 1 specifically refers to its diameter. When the cross-section is square, the overall tapered silicon core 1 is frustum-shaped, and the stepped structure includes two connected cubes. The maximum width of the silicon core 1 specifically refers to its side length.
[0042] Example 4
[0043] In another preferred embodiment of this utility model, the utility model includes a silicon core assembly, comprising a crossbeam 5 and the novel silicon core structure described in any of the embodiments 1 to 3 above. Specifically, the top of the silicon core 1 is further provided with an overlapping hole 4. (Refer to the appendix of the specification.) Figure 4 The two ends of the crossbeam 5 are respectively used to insert into the overlapping holes 4 of two adjacent silicon cores 1.
[0044] Example 5
[0045] As another preferred embodiment of this utility model, this utility model includes a reduction furnace structure, as shown in the attached specification. Figure 1 The reduction furnace includes the furnace body and the novel silicon core structure described in any of the embodiments 1 to 3 above. The novel silicon core structure is assembled into a silicon core assembly via crossbeams 5 and is disposed inside the furnace body. Specifically, the reduction furnace includes a bell jar 6 and a chassis, among other components. The bell jar 6 is mounted on the chassis, which has cooling channels for cooling the chassis. Nozzles, exhaust ports, electrodes, and other components are distributed on the chassis.
[0046] The bell jar 6 includes a connected cylindrical section 7 and an arc section 8. The height h of the cylindrical section 7 is 3.3m, and the vertical height L of the arc section 8 is 0.79m. The inner wall material of the cylindrical section 7 is Hastelloy C-22 or nickel-silver alloy, and the inner wall material of the arc section 8 is 316L.
[0047] Furthermore, the bell jar 6 adopts a sandwich structure to form a cooling channel 9, which is connected to an inlet pipe and an outlet pipe 10. The outlet pipe 10 is located at the top of the bell jar 6. The outlet pipe 10 is U-shaped and includes a first pipe, a straight section 12, and a second pipe connected in sequence. The straight section 12 is located in the middle. The first pipe connects downwards to the outlet of the cooling channel 9 of the bell jar 6, and the outlet of the second pipe is downwards. The reduction furnace includes an exhaust pipe 11. The exhaust pipe 11 is also U-shaped, with one end connected to the top of the straight section 12 and the other end downwards with a valve 13 at the end.
[0048] In summary, any other corresponding modifications made by those skilled in the art based on the technical solution and concept of this utility model without creative mental effort after reading this utility model document are all within the scope of protection of this utility model.
Claims
1. A novel silicon core structure characterized by: The silicon core (1) adopts an integral tapered structure or a stepped structure; the integral tapered structure specifically refers to the cross-sectional size of the silicon core (1) decreasing continuously along the axial direction from the top to the bottom; the stepped structure specifically refers to the silicon core (1) including a first silicon core segment (2) and a second silicon core segment (3) connected in sequence from the top to the bottom, wherein the cross-sectional size of the first silicon core segment (2) is larger than the cross-sectional size of the second silicon core segment (3).
2. A novel silicon core structure according to claim 1, characterized by: The length ratio of the first silicon core segment (2) to the second silicon core segment (3) is (0.22~0.3):1; the maximum width of the first silicon core segment (2) is 15 mm~25 mm, and the maximum width of the second silicon core segment (3) is 5 mm less than the maximum width of the first silicon core segment (2).
3. A novel silicon core structure according to claim 1, characterized by: When the silicon core (1) adopts an overall tapered structure, the maximum width of the top of the silicon core (1) is 15 mm ~ 25 mm, and the maximum width of the bottom of the silicon core (1) is 5 mm smaller than the maximum width of the top.
4. A silicon core assembly characterized by: The novel silicon core structure includes any one of claims 1 to 3 above.
5. A silicon core assembly according to claim 4, wherein: The silicon core (1) is also provided with an overlap hole (4) at the top.
6. A silicon core assembly according to claim 5, wherein: It also includes a crossbeam (5), the two ends of which are used to be inserted into the overlapping holes (4) of two adjacent silicon cores (1).
7. A reduction furnace structure, characterized by: The novel silicon core structure includes any one of claims 1 to 3 above.
8. A reduction furnace structure according to claim 7, wherein: The reduction furnace structure also includes a bell jar (6), which includes a connected cylindrical section (7) and an arc section (8). The inner wall material of the cylindrical section (7) is Hastelloy C-22 or nickel-silver alloy, and the inner wall material of the arc section (8) is 316L.
9. A reduction furnace structure according to claim 8, wherein: The bell jar (6) adopts a sandwich structure to form a cooling channel (9), which is connected to an inlet pipe and an outlet pipe (10). The outlet pipe (10) is located at the top of the bell jar (6).
10. A reduction furnace structure according to claim 9, wherein: It also includes an exhaust pipe (11); the water outlet pipe (10) is U-shaped and includes a straight section (12) in the middle; one end of the exhaust pipe (11) is connected to the top of the straight section (12), and the other end is set downward and has a valve (13) at the end.