A bottom heater used in a silicon single crystal furnace

Abstract

This application relates to the field of heating equipment technology, and in particular to a bottom heater used in a silicon single crystal furnace, comprising two foot plates and two heating devices. Each of the two foot plates is connected to a graphite electrode on two metal electrode pillars of the furnace bottom plate. The two heating devices are symmetrical about the central axis of the furnace bottom plate. The heating devices are connected to the furnace bottom plate and the foot plates, and the heating devices provide heat to the crucible. This application has the effect of improving the difficulty in achieving uniform heating of the crucible.

Description

Technical Field

[0001] This application relates to the field of heating equipment technology, and in particular to a bottom heater used in a silicon single crystal furnace. Background Technology

[0002] In the Czochralski (CZ) monocrystalline silicon industry (photovoltaics), CZ technology has developed rapidly. Its process of melting, temperature control, crystal pulling, shoulder setting, equal diameter setting, tailing, rod removal and feeding constitutes a complete cycle. The silicon monocrystalline furnace is the core equipment, and the bottom heater plays a key role in it. It is connected to the bottom electrode post and provides the necessary heat for heating the silicon material. As the demand for large-size monocrystalline rods in the photovoltaic market increases, the industry's performance requirements for heaters are also getting higher and higher.

[0003] In the existing Czochralski monocrystalline silicon industry, a bottom heater is conventionally used to assist the main heater in heating the silicon material. Figure 1 Traditional bottom heaters include two heating plates 6 and two heating structures 7. The two heating plates 6 are connected to the positive and negative electrode posts respectively, forming a current path. The two heating structures 7 are centrally symmetrically arranged. Each heating structure 7 includes multiple heating bars 71, which are arranged along the distribution direction of the two heating plates 6. The multiple heating bars 71 are parallel to each other and connected end to end in a rounded transition at the connection. The distance between the two heating bars 71 located in the middle of the two heating structures 7 is greater than the distance between the two heating bars 71 located on the sides of the two heating structures 7. During the melting process, the bottom heater is used for a long time and has a high power each time except for the first feeding. In the entire crystal pulling cycle, the number of cycles for each furnace is determined based on the life of the quartz crucible and the crystal pulling situation. The bottom heater is activated in each melting process.

[0004] Regarding the aforementioned technologies, the heating area is mostly concentrated in the central region. The uneven heat distribution between the central and peripheral regions increases the temperature gradient of the molten silicon inside the crucible, making it difficult to achieve uniform heating of the crucible. Utility Model Content

[0005] To overcome the above problems, this application provides a bottom heater for use in silicon single crystal furnaces.

[0006] The bottom heater used in a silicon single crystal furnace provided in this application adopts the following technical solution: A bottom heater for a silicon single crystal furnace includes two foot plates and two heating devices. Each of the two foot plates is connected to a graphite electrode on two metal electrode pillars of the furnace bottom plate. The two heating devices are symmetrical about the central axis of the furnace bottom plate. The heating devices are connected to the furnace bottom plate and the foot plates, and the heating devices provide heat to the crucible.

[0007] By adopting the above technical solution, the two foot plates are connected to the graphite electrodes on the two metal electrode pillars of the furnace bottom plate to form a current path, which powers the heating device; the two heating devices are centrally symmetrically arranged, which can uniformly provide heat to the crucible and ensure that the silicon material in the crucible is uniformly heated and melted.

[0008] In one specific implementation, the heating device includes a heating part and a heating assembly, a heating ring is connected to the middle of the furnace bottom plate, two heating rings are connected to form a heating ring, and a heating strip is connected to each of the two sides of the heating ring facing each other; The heating assembly includes a first heating unit and a second heating unit. The first heating unit includes multiple first arc-shaped segments, which are spaced apart from the heating ring axis towards the side away from the heating ring axis. The openings of the first arc-shaped segments face the heating ring. All the first arc-shaped segments are connected to the furnace bottom plate. The length of the first arc-shaped segments gradually increases from the heating ring axis towards the side away from the heating ring axis. The multiple first arc-shaped segments are sequentially integrated into an S-shape and connected. The first arc-shaped segments closer to the heating ring are connected to the heating ring, and the first arc-shaped segments closer to the side wall of the furnace bottom plate are connected to the foot plate. The second heating unit includes a connecting part located on the side of the heating strip away from the first arc-shaped segments. The connecting part includes multiple second arc-shaped segments, which are arranged in the same way as the multiple first arc-shaped segments. The second arc-shaped segments closer to the heating ring are connected to the heating strip, and the second arc-shaped segments closer to the side wall of the furnace bottom plate are connected to the foot plate. The connection between adjacent first arc-shaped segments or second arc-shaped segments is a rounded transition.

[0009] By adopting the above technical solution, the heating part of the heating device forms a heating ring. Multiple first arc-shaped segments of the first heating unit are distributed at intervals from the heating ring axis to the side away from the heating ring axis and connected in an S-shape. The arrangement of multiple second arc-shaped segments of the second heating unit is consistent with that of the first arc-shaped segments. This arrangement allows the heating area to gradually diffuse from the center to the periphery, achieving uniform heating and avoiding local overheating or undercooling of the silicon material in the crucible, enabling the silicon material to be uniformly heated and melted. The connection between adjacent first arc-shaped segments or second arc-shaped segments is a circular arc transition, allowing the current to flow more smoothly between the segmented heating areas and reducing current loss. The heating path is longer, the heating area is larger, the maximum current density is reduced, and the temperature difference of the entire bottom heater is reduced, thus resulting in high heating efficiency. The reduced current density reduces the surface temperature, increases the overall lifespan, and reduces the operating cost. The uniform and efficient heating reduces the melting time, shortens the high-temperature reaction time of the silicon material in the crucible, reduces the oxygen content of the single crystal silicon rod, and greatly reduces the energy consumption of the melting material.

[0010] In one specific implementation scheme, the second heating unit further includes a connecting portion located on the side of the second arc segment away from the heating ring. The connecting portion includes multiple third arc segments arranged in the same manner as the multiple first arc segments. One end of the third arc segment near the second arc segment is connected to one end of the second arc segment, and one end of the third arc segment near the side wall of the furnace bottom plate is connected to the foot plate. The side of the third arc segment away from the first arc segment and the side of the second arc segment near the third arc segment form a clearance area for the gas guide cylinder to be accommodated.

[0011] By adopting the above technical solution, a complete heating area is formed, which gradually diffuses from the center to the surrounding area to achieve uniform heating; the current can flow more smoothly between the segmented heating areas, reducing current loss; and a clearance area is formed for the air guide to be accommodated.

[0012] In one specific implementation, the second heating unit further includes an extension located between the air guide tube and the main electrode, and the extension is connected to the second arc-shaped segment.

[0013] By adopting the above technical solution, the extension is located between the air guide tube and the main electrode and is connected to the second arc segment, which can effectively increase the heating area near the air guide tube and the main electrode foot plate, increase the temperature in this area, thereby improving the uniformity of the entire thermal field, making the heat distribution near the air guide tube and the main electrode foot plate more uniform, and reducing the temperature gradient between the central area and the peripheral area of ​​the thermal field.

[0014] In one specific implementation, the heating device further includes a heating component, which includes two first heating units and a second heating unit connected in sequence. The two first heating units are symmetrically arranged on both sides of the second heating unit, and the distance between the two second heating units in the two heating components is greater than the distance between the two first heating units facing each other in the two heating components.

[0015] By adopting the above technical solution, the heating element can generate heat evenly, avoiding local overheating or undercooling, and the heat can be more concentrated in the heating area, thus improving the efficiency of material processing.

[0016] In one specific implementation, the first heating unit includes a plurality of first heating strips. The first heating strips are arranged along a direction perpendicular to the distribution of the two foot plates. Two adjacent first heating strips are arranged in parallel. The plurality of first heating strips are arranged along the distribution of the two foot plates. One end of the first heating strip closest to the foot plate is connected to the foot plate. The remaining first heating strips are connected end to end in sequence. The plurality of first heating strips are arranged in a staggered manner. The second heating unit includes multiple second heating bars, which are arranged in the same way as the multiple first heating bars. The second heating bars that are close to the first heating bars are connected to the first heating bars. The multiple second heating bars are arranged in a staggered manner, and the length of the second heating bars is longer than that of the first heating bars.

[0017] By adopting the above technical solution, the multiple first heating strips of the first heating unit are staggered, and the multiple second heating strips of the second heating unit are staggered with the length of the second heating strip being longer than that of the first heating strip. This makes the heating body heat up evenly and avoids local overheating or overcooling. The staggered arrangement of the heating strips can make the heat more concentrated in the heating area and improve the material processing efficiency.

[0018] In one specific implementation scheme, the connection point of two adjacent second heating bars near the first heating unit is inclined toward the first heating unit.

[0019] By adopting the above technical solution, heat can be more concentrated in the heating area, thereby improving the efficiency of material processing.

[0020] In one specific implementation scheme, the connection between two adjacent first heating strips, the connection between two adjacent second heating strips, and the connection between the first heating strip and the second heating strip are all rounded transitions.

[0021] By adopting the above technical solutions, heat is concentrated in the heating area to improve material processing efficiency, while reducing current loss, further improving heating efficiency, optimizing the heat diffusion path, reducing heat accumulation, and smoothing the transition so that heat flow is uniformly conducted along the curved surface, thereby improving the stability of the thermal field.

[0022] In summary, this application includes at least one of the following beneficial technical effects: 1. The bottom heater used in the designed silicon single crystal furnace has two foot plates connected to the positive and negative electrode pillars to form a current path to power the heating device; the two heating devices are centrally symmetrically arranged, which can uniformly provide heat to the crucible and ensure that the silicon material in the crucible is uniformly heated and melted.

[0023] 2. The bottom heater used in the designed silicon single crystal furnace has multiple second arc-shaped segments in the second heating unit arranged in the same way as the first arc-shaped segment. This arrangement allows the heating area to gradually diffuse from the center to the periphery, achieving uniform heating and avoiding local overheating or undercooling of the silicon material in the crucible, enabling the silicon material to be heated and melted uniformly. The connection between adjacent first or second arc-shaped segments is a rounded transition, allowing the current to flow more smoothly between the segmented heating areas and reducing current loss. The heating path is longer, the heating area is larger, the maximum current density is reduced, and the temperature difference of the entire bottom heater is reduced, thus resulting in high heating efficiency. The reduced current density leads to a lower surface temperature, increased overall lifespan, and lower operating costs. Uniform heating and high efficiency reduce the melting time, shorten the high-temperature reaction time of the silicon material in the crucible, reduce the oxygen content of the single crystal silicon rod, and greatly reduce melting energy consumption.

[0024] 3. The bottom heater used in the designed silicon single crystal furnace has multiple first heating bars in the first heating unit arranged in a staggered manner, and multiple second heating bars in the second heating unit arranged in a staggered manner with the length of the second heating bars being longer than that of the first heating bars. This ensures that the heating element heats up evenly and avoids local overheating or undercooling. The staggered arrangement of the heating bars can make the heat more concentrated in the heating area and improve the material melting efficiency. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure in the prior art.

[0026] Figure 2 This is a schematic diagram of the structure in Example 1.

[0027] Figure 3 This is a structural schematic diagram of one embodiment in Example 2.

[0028] Figure 4 This is a schematic diagram of another implementation scheme in Example 2.

[0029] Figure 5 This is a structural schematic diagram of another embodiment in Example 2.

[0030] Figure 6 This is a schematic diagram of the structure in Example 3.

[0031] Explanation of reference numerals in the attached drawings: 1. Foot plate; 2. Heating section; 3. Heating assembly; 31. First heating unit; 311. First arc-shaped segment; 32. Second heating unit; 321. Connecting part; 3211. Second arc-shaped segment; 322. Connecting part; 3221. Third arc-shaped segment; 323. Extension part; 3231. First extension bar; 3232. Second extension bar; 3233. Third extension bar; 3234. L-shaped bar; 4. Heating assembly; 41. First heating unit; 411. First heating bar; 42. Second heating unit; 421. Second heating bar; 5. Furnace bottom plate; 6. Heating plate; 7. Heating structure; 71. Heating bar. Detailed Implementation

[0032] The following is in conjunction with the appendix Figure 2-6 This application will be described in further detail.

[0033] This application discloses a bottom heater used in a silicon single crystal furnace.

[0034] Example 1 Reference Figure 2 A bottom heater used in a silicon single crystal furnace includes two foot plates 1 and two heating devices, both of which are located on the furnace bottom plate 5.

[0035] Reference Figure 2 Each of the two foot plates 1 is connected to a graphite electrode on one of the two metal electrode posts of the furnace bottom plate 5. The graphite electrode can also be replaced with a carbon-carbon electrode to form a current path. The heating device corresponds one-to-one with the foot plate 1. The two heating devices are symmetrically arranged about the central axis of the furnace bottom plate 5. The heating device includes a heating part 2 and a heating assembly 3. The heating part 2 is located in the middle of the furnace bottom plate 5 and is fixedly connected to the furnace bottom plate 5 by screws. The two heating parts 2 are integrated to form a heating ring. Two heating strips are provided on the outside of the heating ring. The two heating strips are symmetrically arranged about the central axis of the heating ring and are integrated with the heating part 2.

[0036] Reference Figure 2The heating assembly 3 includes a first heating unit 31 and a second heating unit 32. The first heating unit 31 includes multiple first arc-shaped segments 311, which are spaced apart from the heating ring axis towards the side away from the heating ring axis. The openings of the first arc-shaped segments 311 face the heating ring, and all the first arc-shaped segments 311 are fixedly connected to the furnace bottom plate 5 by screws. This arrangement allows the heating area to gradually diffuse from the center to the periphery, thereby achieving uniform heating. The multiple first arc-shaped segments 311 are located on the same plane as the heating ring and are concentrically arranged. The length of the first arc-shaped segments 311 is determined by... The heating ring axis gradually increases in size towards the side away from the heating ring axis. The two adjacent first arc segments 311 are connected end to end in an integrated manner, forming an S-shaped connection. The end of the first arc segment 311 near the heating ring that is not connected to the adjacent first arc segment 311 is integrated with the heating bar. The connection between the two adjacent first arc segments 311 is a rounded transition. This connection method allows the current to flow more smoothly between the segmented heating areas, reducing current loss. The end of the first arc segment 311 near the side wall of the furnace bottom plate 5 that is not connected to the adjacent first arc segment 311 is integrated with the foot plate 1, forming a current path.

[0037] Reference Figure 2 The second heating unit 32 includes a connecting part 321 and a communicating part 322. The connecting part 321 is located on the side of the heating strip away from the first arc segment 311. The connecting part 321 includes a plurality of second arc segments 3211. The plurality of second arc segments 3211 are distributed at intervals from the heating ring axis toward the side away from the heating ring axis. The opening of the second arc segment 3211 faces the heating ring. The length of the second arc segment 3211 gradually increases from the heating ring axis toward the side away from the heating ring axis. The ends of two adjacent second arc segments 3211 are connected in an integrated manner. The connection between two adjacent second arc segments 3211 is an arc transition. The end of the second arc segment 3211 near the heating ring that is not connected to the adjacent second arc segment 3211 is integrated with the heating strip.

[0038] Reference Figure 2The connecting portion 322 is located on the side of the second arc-shaped segment 3211 away from the heating ring, and the connecting portion 322 is located at the end of the second arc-shaped segment 3211 near the side wall of the furnace bottom plate 5 that is not connected to the adjacent second arc-shaped segment 3211. The connecting portion 322 includes a plurality of third arc-shaped segments 3221, which are spaced apart from the heating ring axis toward the side away from the heating ring axis. The openings of the third arc-shaped segments 3221 face the heating ring, and the length of the third arc-shaped segments 3221 gradually increases from the heating ring axis toward the side away from the heating ring axis. One end of the third arc segment 3221 near the second arc segment 3211 is integrally connected to one end of the second arc segment 3211 near the side wall of the furnace bottom plate 5, and the other end of the third arc segment 3221 near the side wall of the furnace bottom plate 5 is integrally connected to the foot plate 1, forming a complete heating area; the side of the third arc segment 3221 away from the first arc segment 311 and the side of the second arc segment 3211 near the third arc segment 3221 form a clearance area for the gas guide tube to be accommodated; the two heating components 3 are connected in parallel, so even if one of the heating components 3 fails, This will not affect the normal operation of the other heating component 3, thus improving the overall reliability of the heater. In this embodiment, current can pass through the first arc segment 311, the second arc segment 3211, and the third arc segment 3221. The current passing through the first arc segment 311, the second arc segment 3211, and the third arc segment 3221 forms a heating zone, thereby providing heat to the crucible and ensuring that the silicon material in the crucible is uniformly heated and melted. The heating path is extended, the heating zone is enlarged, the heating area is uniform, the maximum current density is reduced, and the temperature difference of the entire bottom heater is reduced. Therefore, the heating efficiency is high; after the heating path is extended, the current density decreases, the surface temperature also decreases, the overall lifespan increases, and the cost of use decreases; due to the uniform heating and high efficiency, the melting time is reduced, the high-temperature reaction time of silicon material in the crucible is shortened, and the oxygen content of the single crystal silicon rod is reduced; due to the large heating area and sufficient heat, the melting time is short, and the energy consumption of the melting material is greatly reduced. In this embodiment, the materials of the first arc segment 311, the second arc segment 3211, and the third arc segment 3221 are not limited, and can be carbon-carbon, carbon ceramic, graphite, tungsten metal, etc.

[0039] The implementation principle of Example 1 is as follows: Through the coordinated operation of the heating ring, the first heating unit 31, and the second heating unit 32, a uniform and extensive heating area is formed. The special arrangement and connection method of multiple arc-shaped segments allows the current to flow smoothly, reducing current loss and improving heating efficiency. The heating area gradually diffuses from the center to the periphery, avoiding local overheating or undercooling of the silicon material in the crucible, allowing the silicon material to be heated and melted uniformly. At the same time, the increase in the heating path and the enlargement of the heating area reduces the maximum current density, reduces the temperature difference of the entire bottom heater, extends the overall life of the heater, and reduces the operating cost. In addition, due to the uniform heating and high efficiency, the melting time is reduced, shortening the high-temperature reaction time of the silicon material in the crucible, reducing the oxygen content of the single crystal silicon rod, and greatly reducing the energy consumption of the melting material.

[0040] Example 2 Reference Figure 3 The difference between this embodiment and Embodiment 1 is that the second heating unit 32 further includes an extension 323, which is located between the gas guide tube and the main electrode. The extension 323 includes a first extension strip 3231, a second extension strip 3232, a third extension strip 3233, and an L-shaped strip 3234. In one embodiment, the first extension strip 3231 is arranged along the diameter direction of the heating ring. One end of the first extension strip 3231 can be integrally connected to the second arc segment 3211 adjacent to the side wall of the furnace bottom plate 5, or it can be integrally connected to the second arc segment 3211 adjacent to the side wall of the furnace bottom plate 5. In this embodiment, one end of the first extension strip 3231 can be integrally connected to the second arc segment 3211 adjacent to the side wall of the furnace bottom plate 5, and the other end can be integrally connected to one end of the second extension strip 3232. The second extension strip 3232 is arranged perpendicular to the first extension strip 3231 and is located away from the third arc segment of the first extension strip 3231. On one side of 3221, the other end of the second extension strip 3232 is integrally connected to one end of the third extension strip 3233. The third extension strip 3233 is set perpendicular to the second extension strip 3232 and is located on the side of the second extension strip 3232 away from the heating ring. One end of the L-shaped strip 3234 is integrally connected to the other end of the third extension strip 3233, and the other end is integrally connected to the second arc-shaped segment 3211 near the side wall of the furnace bottom plate 5. The opening of the L-shaped strip 3234 faces the first extension strip 3231. The first extension strip 3231, the second extension strip 3232, the third extension strip 3233 and the L-shaped strip 3234 are connected to form an L-shaped structure. The L-shaped structure is located between the gas guide tube and the main electrode, forming a surrounding coverage layout. This layout can effectively increase the heating area near the gas guide tube and the main electrode foot plate 1, increase the temperature in this area, thereby improving the uniformity of the entire heat field, making the heat distribution near the gas guide tube and the main electrode foot plate 1 more uniform, and reducing the temperature gradient between the central area and the outer area of ​​the heat field.

[0041] Reference Figure 3 and Figure 4In another embodiment, the L-shaped rod is divided into a vertical section and a horizontal section. One end of the vertical section can be integrally connected to the second arc-shaped section 3211 adjacent to the side wall of the furnace bottom plate 5, or it can be integrally connected to the second arc-shaped section 3211 adjacent to the side wall of the furnace bottom plate 5. In this embodiment, one end of the vertical section is integrally connected to the second arc-shaped section 3211 adjacent to the side wall of the furnace bottom plate 5. The vertical section is arranged along the diameter direction of the heating ring. The other end of the vertical section is integrally connected to one end of the horizontal section. One end of the first extension bar 3231 is connected to the side wall of the furnace bottom plate 5. The second arc-shaped segment 3211 of the side wall of the base plate 5 is integrally connected, and the other end is connected to the second extension strip 3232. The second extension strip 3232 is inclined from the vertical segment to the first extension strip 3231 towards the side away from the vertical segment. The connection between the first extension strip 3231 and the second extension strip 3232 is an arc transition. The other end of the second extension strip 3232 is integrally connected to the other end of the horizontal segment, and the connection is an arc transition. This optimizes the heat diffusion path, reduces heat accumulation, and the smooth transition allows the heat flow to be uniformly conducted along the curved surface, improving the thermal field stability, reducing the risk of thermal fatigue, and increasing the service life.

[0042] Reference Figure 3 and Figure 5 In another embodiment, one end of the first extension strip 3231 is connected to the second arc-shaped segment 3211 near the side wall of the furnace bottom plate 5 or the second arc-shaped segment 3211 adjacent to the side wall of the furnace bottom plate 5, and the other end is integrally connected to one end of the vertical segment. The other end of the vertical segment is connected to the second arc-shaped segment 3211 adjacent to the side wall of the furnace bottom plate 5 or the second arc-shaped segment 3211 near the side wall of the furnace bottom plate 5. The connection between the first extension strip 3231 and the vertical segment is a circular arc transition.

[0043] The implementation principle of Example 2 is as follows: The extension 323 effectively increases the heating area near the air guide tube and the main electrode foot plate 1, raising the temperature in this area and thus improving the uniformity of the entire thermal field. This makes the heat distribution near the air guide tube and the main electrode foot plate 1 more uniform, reducing the temperature gradient between the central and peripheral areas of the thermal field. This surrounding coverage layout further optimizes the heating effect of the heater and improves the production quality of the single crystal silicon rod.

[0044] Example 3 Reference Figure 6The difference between this embodiment and Embodiment 1 is that the heating device further includes a heating element 4. Two heating elements 4 are symmetrically arranged along the central axis of the furnace bottom plate 5. The heating element 4 includes two first heating units 41 and one second heating unit 42 connected in sequence. The two first heating units 41 are symmetrically arranged on both sides of the second heating unit 42. The first heating unit 41 includes multiple first heating strips 411. The first heating strips 411 are arranged along a direction perpendicular to the distribution of the two foot plates 1. Adjacent first heating strips 411 are arranged parallel to each other. The multiple first heating strips 411 are arranged along the distribution of the two foot plates 1. One end of the first heating strip 411 closest to the foot plate 1 is integrally connected to the foot plate 1. The remaining first heating strips 411 are connected end to end in sequence. The lengths of the multiple first heating strips 411 are staggered. The second heating unit 42 includes multiple second heating strips 421. The second heating strips 421 are arranged along a direction perpendicular to the distribution of the two foot plates 1. Adjacent second heating strips 421 are parallel to each other. The design incorporates multiple second heating strips 421 arranged along the distribution direction of the two foot plates 1. The second heating strip 421 closest to the first heating strip 411 is integrally connected to the first heating strip 411. The lengths of the multiple second heating strips 421 are staggered, which allows the heating element to heat up evenly and avoids local overheating or undercooling. The remaining second heating strips 421 are connected end to end. The connections between adjacent first heating strips 411, adjacent second heating strips 421, and the connections between first heating strips 411 and second heating strips 421 are all arc transitions. The connection points between adjacent second heating strips 421 closest to the first heating unit 41 are inclined towards the first heating unit 41. The length of the second heating strip 421 is longer than the length of the first heating strip 411, and the distance between two second heating units 42 is greater than the distance between two directly opposite first heating units 41 in the two heating components 4. This structural design allows the heat to be more concentrated in the heating area, improving the material processing efficiency.

[0045] The implementation principle of Example 3 is as follows: This structural design allows the heating element to heat up evenly, avoiding localized overheating or underheating. The staggered arrangement of heating strips and heating paths concentrates heat in the heating area, improving material processing efficiency. Simultaneously, the rounded transitions at the joints of the heating strips reduce current loss, further enhancing heating efficiency.

[0046] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A bottom heater used in a silicon single crystal furnace, characterized in that: It includes two foot plates (1) and two heating devices. Each of the two foot plates (1) is connected to a graphite electrode on one of the two metal electrode pillars of the furnace bottom plate (5). The two heating devices are symmetrical about the central axis of the furnace bottom plate (5). The heating devices are connected to the furnace bottom plate (5) and the foot plates (1). The heating devices provide heat to the crucible.

2. The bottom heater used in a silicon single crystal furnace according to claim 1, characterized in that: The heating device includes a heating part (2) and a heating component (3). The heating ring is connected to the middle of the furnace bottom plate (5). The two heating rings are connected to form a heating ring. A heating strip is connected to each side of the heating ring. The heating assembly (3) includes a first heating unit (31) and a second heating unit (32). The first heating unit (31) includes a plurality of first arc-shaped segments (311). The plurality of first arc-shaped segments (311) are spaced apart from the heating ring axis toward the side away from the heating ring axis. The openings of the first arc-shaped segments (311) face the heating ring. The plurality of first arc-shaped segments (311) are all connected to the furnace bottom plate (5). The length of the first arc-shaped segments (311) gradually increases from the heating ring axis toward the side away from the heating ring axis. The plurality of first arc-shaped segments (311) are sequentially integrated in an S-shape. The first arc-shaped segments (311) near the heating ring are connected to the heating ring. The first arc-shaped segments (311) near the side wall of the furnace bottom plate (5) are connected to the heating ring. The arc segment (311) is connected to the foot plate (1). The second heating unit (32) includes a connecting part (321). The connecting part (321) is located on the side of the heating strip away from the first arc segment (311). The connecting part (321) includes multiple second arc segments (3211). The arrangement of the multiple second arc segments (3211) is consistent with the arrangement of the multiple first arc segments (311). The second arc segment (3211) near the heating ring is connected to the heating strip. The second arc segment (3211) near the side wall of the furnace bottom plate (5) is connected to the foot plate (1). The connection between adjacent first arc segments (311) or second arc segments (3211) is a rounded transition.

3. The bottom heater used in a silicon single crystal furnace according to claim 2, characterized in that: The second heating unit (32) further includes a connecting part (322), which is located on the side of the second arc segment (3211) away from the heating ring. The connecting part (322) includes a plurality of third arc segments (3221), which are arranged in the same way as the plurality of first arc segments (311). One end of the third arc segment (3221) near the second arc segment (3211) is connected to one end of the second arc segment (3211), and one end of the third arc segment (3221) near the side wall of the furnace bottom plate (5) is connected to the foot plate (1). The side of the third arc segment (3221) away from the first arc segment (311) and the side of the second arc segment (3211) near the third arc segment (3221) form a clearance area for the gas guide tube to be accommodated.

4. The bottom heater used in a silicon single crystal furnace according to claim 3, characterized in that: The second heating unit (32) further includes an extension (323) located between the air guide tube and the main electrode, and the extension (323) is connected to the second arc-shaped segment (3211).

5. A bottom heater for a silicon single crystal furnace according to claim 1, characterized in that: The heating device also includes a heating component (4), which includes two first heating units (41) and a second heating unit (42) connected in sequence. The two first heating units (41) are symmetrically arranged on both sides of the second heating unit (42). The distance between the two second heating units (42) in the two heating components (4) is greater than the distance between the two first heating units (41) facing each other in the two heating components (4).

6. A bottom heater for a silicon single crystal furnace according to claim 5, characterized in that: The first heating unit (41) includes a plurality of first heating strips (411). The first heating strips (411) are arranged in a direction perpendicular to the distribution of the two foot plates (1). Two adjacent first heating strips (411) are arranged in parallel. The plurality of first heating strips (411) are arranged in a direction along the distribution of the two foot plates (1). One end of the first heating strip (411) closest to the foot plate (1) is connected to the foot plate (1). The remaining first heating strips (411) are connected end to end in sequence. The plurality of first heating strips (411) are arranged in a staggered manner. The second heating unit (42) includes a plurality of second heating bars (421). The arrangement of the plurality of second heating bars (421) is consistent with the arrangement of the plurality of first heating bars (411). The second heating bars (421) close to the first heating bar (411) are connected to the first heating bar (411). The plurality of second heating bars (421) are staggered and the length of the second heating bar (421) is greater than the length of the first heating bar (411).

7. A bottom heater for a silicon single crystal furnace according to claim 6, characterized in that: The connection point of two adjacent second heating bars (421) near the first heating unit (41) is inclined toward the first heating unit (41).

8. A bottom heater for a silicon single crystal furnace according to claim 6, characterized in that: The connection between two adjacent first heating bars (411), the connection between two adjacent second heating bars (421), and the connection between the first heating bar (411) and the second heating bar (421) are all arc transitions.

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