A double-beam silicon core structure

Abstract

The utility model discloses a double crossbeam silicon core structure belongs to polycrystal silicon production technical field, including upper silicon core bridge beam, lower silicon core bridge beam and two silicon core column bodies. The upper silicon core bridge beam both ends are equipped with first radial hole, and are connected with the top of silicon core column body, and the second radial hole is equipped with to two silicon core column bodies same height, and is connected with the both ends of lower silicon core bridge beam. The technical scheme forms the rectangular frame through double crossbeam, and improves structural stability, and the lower crossbeam realizes current shunt, and reduces the current density of upper portion, and balances upper and lower temperature, solves the uneven growth of silicon rod, crossbeam angle melting problem, and adopts silicon - silicon homogeneity connection to avoid impurity pollution, and adapts polycrystal silicon production demand.

Description

Technical Field

[0001] This utility model belongs to the field of polycrystalline silicon production technology, specifically relating to a double-beam silicon core structure. Background Technology

[0002] Polysilicon, as a core raw material for the semiconductor and photovoltaic industries, relies heavily on the stability and rationality of its silicon core structure within the reduction furnace during production. This directly determines the growth quality, production efficiency, and energy consumption of polysilicon rods. The silicon core, serving as the substrate for polysilicon deposition, requires a stable current loop within the reduction furnace. Through a high-temperature reduction reaction, silicon atoms continuously deposit and thicken, ultimately forming a polysilicon rod. Therefore, the design of the silicon core structure has always been a key direction for optimizing polysilicon production technology.

[0003] In the prior art, some progress has been made in improving the silicon core structure. For example, Chinese patent document CN202175563U discloses a conical silicon core deposition substrate for a reduction furnace. By setting conical holes at both ends of the silicon core bridge and connecting them with the conical top of the long silicon core, the contact area is increased to reduce resistance and improve structural stability to a certain extent. Chinese patent document CN113104853A proposes a plug-in silicon core structure, which further enhances the connection reliability between the crossbeam and the silicon core by cooperating with the plug-in ends of the first and second silicon cores. However, existing silicon core structures (including the above-mentioned improved schemes) still have many technical defects that urgently need to be solved, which seriously restrict the quality and efficiency of polysilicon production.

[0004] Specifically, the main problems with existing technologies are as follows:

[0005] 1) Insufficient structural stability, easily leading to operational interruptions. Existing silicon core structures mostly employ an inverted U-shaped design with a single crossbeam (such as the silicon core bridge and long silicon core combination in patent CN202175563U, and the single crossbeam plug-in structure in patent CN113104853A). The silicon core and crossbeam are connected only through two points of contact. During pressure testing, this connection method makes the crossbeam susceptible to uneven stress due to slight shaking of the silicon core, potentially causing the crossbeam to detach and resulting in pressure testing failure. Although patent CN202175563U improves contact reliability through a tapered fit and patent CN113104853A through a plug-in structure, the fundamental two-point contact of the single crossbeam remains unchanged, limiting the structure's resistance to disturbances and making it impossible to completely avoid the risk of crossbeam detachment.

[0006] 2) Inconsistent growth rates between the upper and lower parts of the silicon core. During polycrystalline silicon growth, the upper and lower parts of each silicon core are powered through the same current loop, theoretically resulting in equal current values ​​and consistent heating power. However, reduction furnaces generally adopt a bottom-feed mode, where the raw material gas enters from the bottom and flows upward along the silicon core, then exits through a top reversal, causing the gas temperature at the lower part of the silicon core to be significantly lower than that at the upper part. Even though patents CN202175563U and CN113104853A optimized the connection structure between the silicon core and the crossbeam, they did not address the temperature gradient caused by the airflow. This resulted in a difference in growth rate from the early stages of silicon core growth, with the lower part growing slowly and the upper part growing too fast, ultimately forming silicon rods of uneven thickness, affecting product consistency.

[0007] 3) Temperature differences between the upper and lower parts of the silicon rod lead to low-quality products. The reduction furnace has a bell-shaped structure, and during production, the inner wall of the furnace reflects heat from the surface of the silicon rod. In the existing single-beam silicon core structure, the lower part of the silicon rod is blocked by the furnace wall, and the area receiving reflected heat is much smaller than that of the upper part, resulting in the upper part of the silicon rod consistently having a higher temperature than the lower part. This temperature difference has not been improved in the structures of patents CN202175563U and CN113104853A, making the upper part of the silicon rod prone to producing low-quality products such as coral material and loose material due to high temperature, which seriously reduces the yield of polysilicon.

[0008] 4) Melting at the corner of the crossbeam can lead to operational failure. Due to the excessively high temperature at the upper part of the silicon rod (especially at the angle between the crossbeam and the vertical silicon core), and the poor heat dissipation conditions in this area of ​​the existing single-beam structure, the crossbeam is highly susceptible to melting due to localized overheating during growth. While the tapered connection in patent CN202175563U and the plug-in structure in patent CN113104853A improve connection strength, they do not solve the problem of heat accumulation in the corner area. Crossbeam melting remains a common failure causing reduction furnace operation interruptions, increasing production costs and hindering further reduction of reduction power consumption.

[0009] In summary, the deficiencies of existing silicon core structures in terms of stability, temperature uniformity, and resistance to high-temperature failure have become key bottlenecks restricting the improvement of polysilicon production quality and the reduction of energy consumption. A new type of silicon core structure is urgently needed to overcome these problems. Utility Model Content

[0010] The purpose of this invention is to address the shortcomings of existing technologies by proposing a double-beam silicon core structure. When the silicon core is energized, the two upper silicon cores shunt the current, significantly reducing the current flow from the lower beam upwards. This ensures that the temperature of the silicon core below the lower beam remains unaffected while significantly reducing the temperature of the upper silicon core. This effectively solves the problem of "cornflower-like" growth on the upper part of the silicon rod during production. Furthermore, without the threat of melting silicon at the top, the range of process adjustments can be further expanded, increasing the overall growth rate, improving quality, and reducing consumption.

[0011] The above objectives are achieved through the following technical solutions:

[0012] A double-beam silicon core structure includes an upper silicon core bridge beam, a lower silicon core bridge beam, and two identical silicon core pillar bodies. The two ends of the upper silicon core bridge beam are provided with first radial holes that support each other. The tops of the two silicon core pillar bodies are respectively connected to the upper silicon core bridge beam through two first radial holes. The two silicon core pillar bodies are respectively provided with second radial holes at the same height position. The two ends of the lower silicon core bridge beam are respectively connected to the two silicon core pillar bodies through corresponding second radial holes.

[0013] Preferably, the first radial hole is a first conical hole, and the top of the silicon core pillar body is provided with a first conical connector with the same taper as the first conical hole; the silicon core pillar body and the upper silicon core bridge beam are connected by the first conical connector and the first conical hole.

[0014] Preferably, the second radial hole is a second conical hole, and the end of the lower silicon core bridge beam is provided with a second conical joint with the same taper as the second conical hole; the lower silicon core bridge beam and the silicon core column body are connected by the second conical joint and the second conical hole.

[0015] Preferably, the cross-section of the upper silicon core bridge beam is circular or square; for an upper silicon core bridge beam with a circular cross-section, the diameter of its first radial hole is ≤ 2 / 3 of the diameter of the upper silicon core bridge beam; for an upper silicon core bridge beam with a square cross-section, the diameter of its first radial hole is ≤ 2 / 3 of the width of the upper silicon core bridge beam.

[0016] Preferably, the cross-section of the silicon core pillar body is circular or square; for a silicon core pillar body with a circular cross-section, the diameter of its second radial hole is ≤ 2 / 3 of the diameter of the silicon core pillar body; for a silicon core pillar body with a square cross-section, the diameter of its second radial hole is ≤ 2 / 3 of the diameter of the silicon core pillar body.

[0017] Preferably, the diameter of the lower silicon core bridge beam is less than or equal to the diameter of the upper silicon core bridge beam and less than or equal to the diameter of the silicon core column body.

[0018] Preferably, the installation position of the lower silicon core bridge beam is 300~800mm away from the upper silicon core bridge beam.

[0019] Preferably, the length of the silicon core pillar body is 2800~3400mm.

[0020] Preferably, the bottom of the silicon core pillar body is provided with a third tapered connector for connecting the graphite clamping member.

[0021] This technical solution has the following beneficial effects:

[0022] 1) The double-beam silicon core structure of this technical solution significantly improves the overall structural stability. It forms a symmetrical rectangular frame structure with the upper and lower silicon core bridge beams and the two silicon core pillars, ensuring uniform stress distribution at each connection point. This effectively disperses the weight and thermal expansion stress during silicon rod growth, preventing fractures caused by localized stress concentration. Simultaneously, the use of tapered connections, with the design of the first / second tapered holes and corresponding tapered joints, increases the contact area. The normal force of the tapered surface can be decomposed into radial clamping force, enhancing the tightness and anti-loosening ability of the connection, significantly reducing the risk of beam detachment, and solving the problem of weak anti-disturbance capability in single-beam two-point contact structures.

[0023] 2) This technical solution's double-beam silicon core structure optimizes the distribution of current and temperature, effectively improving the uniformity of silicon rod growth. The lower silicon core bridge beam serves as a central current branching point, causing the current to branch into two sections on the silicon core column: an upper section and a lower section. In the upper region, due to the partial current diversion, the current density decreases, resulting in less heat generation; in the lower region, the current density is stable, and the heat is sufficient, balancing the temperatures of the upper and lower sections according to Joule's law. This design adapts to the airflow characteristics of the reduction furnace's bottom feeding and top exhaust, as well as the differences in furnace wall heat reflection, avoiding the situation where the lower part of the silicon core grows slowly and the upper part grows too quickly. This makes the growth rate of the upper and lower parts of the silicon rod more consistent, reducing the phenomenon of uneven thickness.

[0024] 3) The dual-beam silicon core structure of this technical solution reduces the risk of melting at the beam angle and improves operational stability. Compared to the traditional single-beam structure, the upper part of the silicon rod, especially at the angle between the beam and the silicon core column, is prone to local overheating and beam melting due to current concentration and poor heat dissipation. In the dual-beam structure of this technical solution, the temperature is reduced after current diversion in the upper region, and the symmetrical layout of the dual beams optimizes the heat dissipation path, avoiding heat accumulation in the angle area. This significantly reduces operational interruptions caused by beam melting, lowers production cost losses, and also creates conditions for reducing reduction power consumption.

[0025] 4) The double-beam silicon core structure of this technical solution can effectively avoid impurity contamination and ensure the purity of the silicon rod. It adopts a "silicon-silicon homogeneous connection" method, in which the upper and lower silicon core bridge beams are physically connected to the silicon core column body through radial holes. No foreign substances such as adhesives or metal connectors are introduced throughout the process, which eliminates the risk of impurity contamination at the structural level, ensures the initial purity of the silicon core, and avoids semiconductor performance degradation caused by impurities.

[0026] 5) This technical solution's double-beam silicon core structure boasts strong parameter adaptability and a wide range of applications. The cross-sections of the upper and lower silicon core bridge beams and the silicon core pillar body can be selected as circular or square, with the radial hole diameter strictly limited to within 2 / 3 of the corresponding component size. This ensures sufficient material thickness while meeting connection requirements, maintaining structural strength. The distance between the lower and upper silicon core bridge beams, as well as the length of the silicon core pillar body, are adjustable to accommodate the spatial dimensions of different furnace types. The diameter gradient design matches the current load, adapting to different electrical parameters and enhancing the structure's versatility. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of a preferred double-beam silicon core structure;

[0028] Figure 2 This is a schematic diagram of a preferred top-mounted silicon core bridge beam structure viewed from below;

[0029] Figure 3 A schematic diagram of the side structure of a preferred silicon core pillar body;

[0030] Figure 4 This is a schematic diagram of a preferred lower silicon core bridge beam structure.

[0031] In the picture:

[0032] 1. Upper silicon core bridge beam; 1.1. First radial hole; 2. Lower silicon core bridge beam; 2.1. Second tapered joint; 3. Silicon core pillar body; 3.1. First tapered joint; 3.2. Second tapered hole; 3.3. Third tapered joint. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of this utility model clearer, the technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments.

[0034] Therefore, the following detailed description of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0035] Example 1

[0036] This embodiment discloses a double-beam silicon core structure, as a preferred implementation of this technical solution, such as... Figure 1As shown, it includes an upper silicon core bridge beam 1, a lower silicon core bridge beam 2, and two identical silicon core pillar bodies 3.

[0037] As the "seed" for polycrystalline silicon growth, the purity of the silicon core directly affects the quality of the final silicon rod (impurities lead to semiconductor performance degradation). This technical solution employs a "radial hole direct connection" approach, where through-holes are machined on the upper silicon core bridge beam 1 and the silicon core pillar body 3, achieving connection through physical interlocking, without introducing foreign substances such as adhesives or metal connectors. Specifically: the two ends of the upper silicon core bridge beam 1 are provided with first radial holes 1.1 supporting each other; the tops of the two silicon core pillar bodies 3 are horizontally connected to the upper silicon core bridge beam through two first radial holes 1.1 respectively; second radial holes are provided at the same height positions on the two silicon core pillar bodies 3, and the two ends of the lower silicon core bridge beam 2 are connected to the two silicon core pillar bodies 3 through corresponding second radial holes. This design strictly adheres to the principle of "silicon-silicon homogeneous connection," eliminating the risk of impurity contamination at the structural level and ensuring the initial purity of the silicon core. In addition, in this structure, the upper silicon core bridge beam 1, the lower silicon core bridge beam 2, and the two silicon core pillars 3 work together to form a "rectangular frame structure". This symmetrical layout ensures that the stress at each connection point is uniform (the silicon core will generate stress due to thermal expansion during high-temperature growth), avoiding the risk of fracture caused by local stress concentration. At the same time, the interlocking connection between the beams and the pillars, compared with the suspended or overlapping structure, can more stably bear the weight of the silicon rod during the growth process, improving the overall structure's resistance to deformation.

[0038] In traditional single-beam structures, current flows through only the top beam, forming a single path (current flows from the top beam into the two silicon core pillars 3 without any branching), resulting in consistent current density in the upper and lower regions of the silicon core pillars. This technical solution creates controllable multiple current paths through a "double-beam layered layout": the upper silicon core bridge beam 1 is located at the top of the silicon core pillar, and the lower silicon core bridge beam 2 is located at the upper-middle height of the silicon core pillar body 3, forming an "upper and lower branching node." Structurally, the lower silicon core bridge beam 2 bears the initial current input, while the upper silicon core bridge beam 1 acts as a current branching branch, causing the current to form two branches on the silicon core pillar body 3: "upper (above the lower silicon core bridge beam) - lower (below the lower silicon core bridge beam)."

[0039] Current shunting mechanism: After power is applied, current flows from the lower silicon core bridge beam 2, which acts as the main path carrying all the current (because the resistivity of the silicon core is high at low temperatures, the current preferentially flows through the path with lower resistance). As the temperature of the lower silicon core bridge beam 2 and the silicon core pillar body 3 increases (the resistivity of the silicon core decreases), the current gradually diffuses upward to the upper silicon core bridge beam 1, forming a dual-path structure with current shunting between the upper and lower beams. Start-up phase—The current flows completely through the lower silicon core bridge beam 2, through the two silicon core pillar bodies 3, to the top electrode. At this time, the upper silicon core bridge beam 1, due to its low temperature and extremely high resistance, experiences almost no current flow. Heating phase—When the temperature of the silicon core pillar body 3 rises to the conduction temperature (e.g., 600-800℃), the resistivity drops sharply (breakdown), and the upper silicon core bridge beam 1 begins to conduct. Some current flows laterally from the upper part of the silicon core pillar body 3 into the upper silicon core bridge beam 1, forming a current shunting. The current shunting ratio is related to the temperature difference between the upper silicon core bridge beam 1 and the lower silicon core bridge beam 2 (the greater the temperature difference, the more obvious the current shunting). In the stable phase—once the temperature difference between the upper silicon core bridge beam 1 and the lower silicon core bridge beam 2 stabilizes, the current distribution ratio also tends to stabilize. Some current is shunted through the upper silicon core bridge beam 1, reducing the current density in the upper region of the silicon core pillar body 3, keeping the temperature within a safe range; the lower region of the silicon core pillar body 3, without current shunting, maintains a stable current density and a safe temperature.

[0040] Temperature gradient control: Silicon core heating follows Joule's law, with heat proportional to the square of the current. Due to the reduced current density in the upper region of the silicon core pillar 3, the heat generated is decreased. Simultaneously, the impact of heat reflection from the inner wall of the reduction furnace on the upper region is offset by the "low heat generation," causing the upper temperature to drop from the high temperature of the traditional single-beam structure to within the safe temperature range for silicon rod growth. The lower region, with its stable current density, maintains a temperature within the safe temperature range for silicon rod growth, meeting the optimal temperature for polycrystalline silicon deposition. This ultimately creates a gradient of "sufficient lower temperature and controllable upper temperature," adapting to the requirement of uniform growth of the silicon rod from bottom to top.

[0041] Example 2

[0042] This embodiment discloses a double-beam silicon core structure as a preferred implementation of this technical solution, based on Embodiment 1. This embodiment utilizes the "self-locking characteristic" of the conical structure to enhance the connection strength. Specifically, the first radial hole 1.1 is a first conical hole, and the top of the silicon core pillar body 3 is provided with a first conical connector 3.1 (ground cone) with the same taper as the first conical hole. The silicon core pillar body 3 and the upper silicon core bridge beam 1 are connected through the first conical connector 3.1 and the first conical hole, and this connection undertakes the function of shunting after heating. In addition, the top of the first conical connector 3.1 can pass slightly through the first conical hole. When the silicon core pillar body 3 and the upper silicon core bridge beam 1 are assembled, the conical surface forms a tight fit through axial pressure, and the contact area is increased compared with the straight hole structure. Moreover, the normal force of the fitting surface can be decomposed into radial clamping force, effectively resisting the axial tensile force generated by the increase in weight during silicon rod growth and avoiding loosening of the connection.

[0043] When current is conducted in silicon, the contact resistance is inversely proportional to the contact area (the smaller the contact area, the greater the resistance, and the more severe the local heating). The tapered fit design increases the contact area, making the current path more dispersed (changing from single-point contact to annular surface contact) when the current is conducted from the silicon core pillar body 3 to the upper silicon core bridge beam 1, reducing the local current density. At the same time, the design of the first tapered connector 3.1 "exceeding the first tapered hole by a small amount at the top" (usually extending 1-3mm) forms a "contact redundancy zone," avoiding poor contact due to assembly errors and ensuring the stability of current conduction. Adaptive adjustment of current conduction: In the initial stage of power-on, the current flows from the lower silicon core bridge beam 2 into the silicon core pillar body 3 through the tapered mating surface where the second tapered connector is located. The lower silicon core bridge beam 2 and the silicon core pillar body 3 generate heat and rise in temperature due to the current flow. As the temperature rises, the tapered mating surface will further adhere due to thermal expansion. Simultaneously, as heat is transferred from the silicon core and reflected from the upper region of the silicon core pillar 3, the area of ​​the silicon core pillar 3 above the lower silicon core bridge beam 2 gradually heats up, reducing resistance and allowing current to flow. As the temperature of the upper silicon core bridge beam 1 gradually matches that of the lower silicon core bridge beam 2, the resistances of the upper and lower silicon core bridge beams 1 and 2 will gradually approach each other, achieving stable current shunting.

[0044] Furthermore, a third tapered connector 3.3 (grinding cone) is provided at the bottom of the silicon core pillar body 3 for connecting the graphite clamping component. The cooperation between the bottom third tapered connector 3.3 and the graphite clamping component provides overall support. The cooperation between the bottom third tapered connector 3.3 and the graphite clamping component continues the advantages of the tapered structure: on the one hand, graphite, as a material with high temperature resistance and excellent electrical conductivity (with a small difference in thermal expansion coefficient compared to silicon core), can achieve a stable connection with the silicon core pillar through the tapered fit; on the other hand, the tapered structure allows for a certain degree of assembly angle deviation, adapting to the installation error of the graphite clamping component in the reduction furnace, and reducing the risk of silicon core pillar breakage due to mechanical stress (silicon material is brittle, and stress concentration easily leads to breakage).

[0045] Example 3

[0046] This embodiment discloses a double-beam silicon core structure as a preferred implementation of this technical solution. Based on embodiment 1 or 2, it further focuses on optimizing the stability of the lower connection structure, the accuracy of current shunting, and the consistency of the overall structure. Specifically: the second radial hole is a second conical hole 3.2, and the end of the lower silicon core bridge beam 2 is provided with a second conical connector 2.1 with the same taper as the second conical hole; the lower silicon core bridge beam 2 and the silicon core column body 3 are connected through the second conical connector 2.1 and the second conical hole 3.2 (correspondingly, the second conical connector 2.1 passes slightly through the second conical hole 3.2). The characteristics of the conical structure enhance the connection stability. The conical fit can significantly increase the contact area between the lower silicon core bridge beam 2 and the silicon core column body 3. This large contact area increases the friction between the two, which can better resist various external forces generated during the growth of the silicon rod, such as the tensile force brought by the weight of the silicon rod itself, and the slight vibration during equipment operation, thereby reducing the displacement and loosening of the connection parts.

[0047] The lower silicon core bridge beam 2 plays a crucial role in carrying and shunting all the current in the double-beam structure, and its connection with the silicon core pillar body 3 directly affects the current conduction effect. The matching design of the second tapered hole 3.2 and the second tapered connector 2.1 ensures the stability and uniformity of current conduction. Due to the tight fit of the tapered contact surfaces, the current will not experience excessive local resistance due to poor contact when passing through this connection, thus ensuring a stable current shunting ratio for the lower silicon core bridge beam 2. Compared to the potential current fluctuations that may occur with straight hole connections, this design allows the current in the upper part of the path of the lower silicon core bridge beam 2 to always remain at the expected low level, providing a reliable current basis for precise temperature control of the upper region of the silicon core pillar body 3.

[0048] Example 2 already used a tapered structure for the connection between the upper and lower silicon core bridge beam 1 and the silicon core pillar body 3. In this example, the connection between the lower and lower silicon core bridge beam 2 and the silicon core pillar body 3 also uses a tapered structure, ensuring that the entire double-beam silicon core structure maintains consistency in its connection method. This consistent design not only facilitates standardized production and processing, reducing process differences caused by different connection methods, but also makes the overall structure more uniform in terms of stress, current conduction, and other characteristics, avoiding local structural performance imbalances caused by different connection methods, and improving the overall structural coordination and reliability.

[0049] Example 4

[0050] This embodiment discloses a double-beam silicon core structure. As a preferred implementation of this technical solution, based on embodiment 1, 2 or 3, the cross-section of the upper silicon core bridge beam 1 is circular or square; for the upper silicon core bridge beam 1 with a circular cross-section, the diameter of its first radial hole 1.1 is ≤ 2 / 3 of the diameter of the upper silicon core bridge beam 1; for the upper silicon core bridge beam 1 with a square cross-section, the diameter of its first radial hole 1.1 is ≤ 2 / 3 of the width of the upper silicon core bridge beam 1.

[0051] Furthermore, the cross-section of the silicon core pillar body 3 is circular or square; for a silicon core pillar body 3 with a circular cross-section, the diameter of its second radial hole is ≤ 2 / 3 of the diameter of the silicon core pillar body 3; for a silicon core pillar body 3 with a square cross-section, the diameter of its second radial hole is ≤ 2 / 3 of the diameter of the silicon core pillar body 3.

[0052] Circular and square cross-sections each have their mechanical advantages. A circular cross-section distributes stress evenly, providing strong resistance to bending and torsion; a square cross-section offers better stability in the planar direction, better able to withstand pressure perpendicular to the cross-section. Limiting the radial hole diameters—specifically, the first radial hole 1.1's diameter not exceeding 2 / 3 of the diameter (circular) or width (square) of the upper silicon core bridge beam 1, and the second radial hole's diameter not exceeding 2 / 3 of the diameter (circular) or width (square) of the silicon core pillar body 3—is to prevent weakening the structure's mechanical strength due to excessively large openings. If the radial hole diameters are too large, the effective load-bearing area of ​​the upper silicon core bridge beam 1 and the silicon core pillar body 3 will be significantly reduced, making it difficult to withstand the weight of the silicon rod and various stresses during equipment operation, potentially leading to structural failures such as fracture. These dimensional limitations ensure sufficient material thickness to maintain the overall structural strength while meeting connection requirements.

[0053] When current is conducted in a conductor, it tends to flow along the path of lower resistance. The cross-sectional shape of the upper silicon core bridge beam 1 and the silicon core pillar body 3, as well as the size of the radial holes, affect the current distribution. With circular cross-sections, the current can be conducted more evenly around the central axis in the upper silicon core bridge beam 1 and the silicon core pillar body 3; while square cross-sections may exhibit some current concentration at the four corners, but with proper design, overall uniformity of conduction can be ensured. Limiting the diameter of the radial holes to no more than 2 / 3 of their corresponding dimensions avoids excessively large holes that would narrow the current conduction path. If the holes are too large, current will concentrate significantly in the area surrounding the holes, causing increased local resistance and exacerbated heating, affecting the uniformity of current conduction and consequently negatively impacting temperature control in different areas of the silicon core pillar.

[0054] Example 5

[0055] This embodiment discloses a double-beam silicon core structure as a preferred implementation of this technical solution. Based on any of embodiments 1-4, it considers the significant differences in current load among different components in the silicon core structure: the silicon core pillar body 3, as the main body for silicon rod growth, needs to bear the main current from the lower silicon core bridge beam 2 to the upper silicon core bridge beam 1, and needs to maintain a stable high-temperature environment to promote polycrystalline silicon deposition; the upper silicon core bridge beam 1 mainly undertakes the upper current splitting function; the lower silicon core bridge beam 2 serves as the current input and intermediate current splitting node. Based on the principle that "current load is positively correlated with conductor cross-sectional area" (the larger the conductor diameter, the larger the cross-sectional area, and the stronger the current carrying capacity), this embodiment designs a gradient relationship of "diameter of the lower silicon core bridge beam 2 ≤ diameter of the upper silicon core bridge beam 1 ≤ diameter of the silicon core pillar body 3," so that the diameter of each component is precisely matched to its current load. The silicon core pillar body 3 has the largest diameter to ensure it can carry the maximum current and is not prone to overheating due to overload; the upper silicon core bridge beam 1 has the second largest diameter to meet the current splitting requirements of the upper part; the lower silicon core bridge beam 2 has the smallest diameter to match its minimum current load and avoid material waste.

[0056] Different furnace types (such as small, medium, and large furnaces) have different internal space dimensions, and the silicon core structure must adapt to the spatial constraints such as electrode spacing and insulation layer position within the furnace. For example, in large furnaces, the silicon core pillar body 3 needs to be longer, and a larger diameter can enhance its bending resistance (an excessively large length-to-diameter ratio can cause it to collapse at high temperatures); while in small furnaces, where space is compact, the diameter of the upper silicon core bridge beam 1 is slightly smaller than the diameter of the silicon core pillar body 3, which can reduce thermal radiation interference caused by being too close to the furnace wall insulation layer. At the same time, different electrical components (such as power supply power and electrode output current) require the total resistance of the silicon core structure to be adapted (too high resistance will cause difficulty in starting, while too low resistance will cause power supply overload). The diameter gradient is used to adjust the resistance of each component (the larger the diameter, the lower the resistance) to match the overall resistance with the power supply parameters, ensuring startup and operational stability.

[0057] The energy loss (Joule heating) when current passes through the silicon core is proportional to the resistance. Under the premise of meeting the current carrying capacity, the lower silicon core bridge beam 2 has the smallest diameter and relatively large resistance, which can supplement the heat of the lower area through moderate heating (the lower area is easily affected by the heat dissipation of the furnace bottom and the temperature is slightly lower); the upper silicon core bridge beam 1 has the next largest diameter and moderate resistance, avoiding excessive heating and aggravating the temperature of the upper part; the silicon core pillar body 3 has the largest diameter and the smallest resistance, reducing useless energy consumption and using more energy for silicon rod growth.

[0058] Example 6

[0059] This embodiment discloses a double-beam silicon core structure as a preferred implementation of this technical solution, based on any one of embodiments 1-5. This embodiment considers factors such as maximizing growth efficiency, furnace space matching, and structural strength balance. Specifically:

[0060] The length of the silicon core pillar body 3 is selected from 2800-3400mm depending on production needs, and the size can be chosen according to different production conditions. The final length of the polycrystalline silicon rod is usually 300-500mm longer than the silicon core pillar body 3 (growth margin). The 2800-3400mm length of the silicon core pillar body 3 can be adapted to the target length of silicon rods in mainstream reduction furnaces. This range is designed based on the "linear relationship between growth time and length": the silicon rod growth rate is about 0.5-1mm / h. If the silicon core pillar body 3 is too short, the final silicon rod length will be insufficient, and the output per furnace will be reduced; if it is too long, the growth cycle will exceed the reasonable range, and impurities in the silicon rod will easily accumulate due to prolonged high temperature. In addition, the bending resistance of the silicon core pillar body 3 at high temperature decreases with increasing length. The 2800-3400mm length range, combined with the diameter design, controls the aspect ratio at 230-425, which is within the safe range of high-temperature bending resistance of silicon materials. If the length exceeds 3400mm, the length-to-diameter ratio is too large, and it is easy to bend due to its own weight or the disturbance of airflow in the furnace, causing the silicon rod to collide and short-circuit.

[0061] Furthermore, the length of the silicon core pillar 3 is proportionally matched to the installation distance of the square silicon core bridge beam relative to the upper silicon core bridge beam 1, that is, the installation position of the lower silicon core bridge beam 2 is 300-800mm away from the upper silicon core bridge beam. This proportional design is based on two reasons: First, during initial breakdown, the silicon core can only break through the lower silicon core bridge beam 2, while the upper silicon core bridge beam 1 needs to be gradually broken through after heating. An excessively long installation distance is detrimental to the heating of the upper region and affects its growth rate. Second, it considers the length distribution between the upper region (requiring cooling) and the lower region (requiring high temperature) to match their respective temperature requirements. An excessively short installation distance would result in insufficient cooling area in the upper region, leading to insufficient improvement in product quality.

Claims

1. A double-beam silicon core structure, characterized in that: It includes an upper silicon core bridge beam (1), a lower silicon core bridge beam (2), and two identical silicon core pillar bodies (3); the two ends of the upper silicon core bridge beam (1) are provided with first radial holes (1.1) supporting each other, and the tops of the two silicon core pillar bodies (3) are respectively connected to the upper silicon core bridge beam through two first radial holes (1.1); the two silicon core pillar bodies (3) are respectively provided with second radial holes at the same height position, and the two ends of the lower silicon core bridge beam (2) are respectively connected to the two silicon core pillar bodies (3) through corresponding second radial holes.

2. The dual-beam silicon core structure as described in claim 1, characterized in that: The first radial hole (1.1) is a first conical hole, and the top of the silicon core pillar body (3) is provided with a first conical connector (3.1) with the same taper as the first conical hole; the silicon core pillar body (3) and the upper silicon core bridge beam (1) are connected by the first conical connector (3.1) and the first conical hole.

3. The dual-beam silicon core structure as described in claim 1, characterized in that: The second radial hole is a second conical hole (3.2), and the end of the lower silicon core bridge beam (2) is provided with a second conical joint (2.1) with the same taper as the second conical hole; the lower silicon core bridge beam (2) and the silicon core column body (3) are connected by the second conical joint (2.1) and the second conical hole (3.2).

4. The dual-beam silicon core structure as described in claim 1, characterized in that: The cross-section of the upper silicon core bridge beam (1) is circular or square; for the upper silicon core bridge beam (1) with a circular cross-section, the diameter of its first radial hole (1.1) is ≤ 2 / 3 of the diameter of the upper silicon core bridge beam (1); for the upper silicon core bridge beam (1) with a square cross-section, the diameter of its first radial hole (1.1) is ≤ 2 / 3 of the width of the upper silicon core bridge beam (1).

5. The dual-beam silicon core structure as described in claim 1, characterized in that: The cross-section of the silicon core pillar body (3) is circular or square; for a silicon core pillar body (3) with a circular cross-section, the diameter of its second radial hole is ≤ 2 / 3 of the diameter of the silicon core pillar body (3); for a silicon core pillar body (3) with a square cross-section, the diameter of its second radial hole is ≤ 2 / 3 of the diameter of the silicon core pillar body (3).

6. The dual-beam silicon core structure as described in claim 1, characterized in that: The diameter of the lower silicon core bridge beam (2) is less than or equal to the diameter of the upper silicon core bridge beam (1) and the diameter of the silicon core column body (3).

7. The dual-beam silicon core structure as described in claim 1, characterized in that: The installation position of the lower silicon core bridge beam (2) is 300~800mm away from the upper silicon core bridge beam (1).

8. The dual-beam silicon core structure as described in claim 1, characterized in that: The length of the silicon core pillar body (3) is 2800~3400mm.

9. The dual-beam silicon core structure as described in claim 1, characterized in that: The bottom of the silicon core pillar body (3) is provided with a third tapered connector (3.3) for connecting the graphite clamping component.

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