Single crystal furnace
By setting up an auxiliary insulation structure and air guide pores in a single crystal furnace, the problem of increasing crystallization difficulty during oxygen reduction in the prior art is solved, and the reduction of silicon liquid oxygen content and crystallization stability are achieved, and the yield is improved.
Patent Information
- Application Number
- CN202420540209.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-03-19
- Publication Date
- 2024-12-24
- Estimated Expiration
- 2034-03-19
AI Technical Summary
When existing single crystal furnaces reduce the liquid oxygen content of silicon, it is easy to increase the difficulty of crystallization and reduce the yield, making it difficult to achieve oxygen reduction and maintain crystallization stability at the same time.
A single crystal furnace is designed, by setting an auxiliary insulation structure on the side of the main heater near the bottom of the furnace, including two independent symmetrical arc plates, and setting a hollow area away from the side of the main heater, and the air guide hole is located in the arc shape. Between the plate and the hollowed-out area, ensure smooth flow of argon gas, reduce the heat radiation from the main heater to the bottom of the crucible, reduce the oxygen content, and maintain the thermal insulation of the heat field.
It effectively reduces the oxygen content in the silicon liquid, maintains the stability and high yield of crystallization, reduces heat loss, and does not affect the crystallization efficiency.
Smart Images
Figure CN222226644U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the field of single crystal manufacturing equipment, and more specifically, to a single crystal furnace. Background Art
[0002] As a basic material for photovoltaic power generation, single crystal silicon wafers have a wide market demand. The direct pulling single crystal silicon growth method is a common single crystal growth method. Its growth process is to immerse the seed crystal into the melt in the single crystal furnace, and then carry out the seeding, shoulder release, shoulder rotation, equal diameter and finishing processes in sequence, and finally obtain a single crystal silicon rod. The thermal field of a single crystal furnace is usually composed of thermal field components and insulation materials, such as a heat shield, a main heater, a bottom heater and an insulation tube. During normal crystal pulling, the main heater is turned on, the bottom heater is turned off, and argon is blown in the single crystal furnace. The heating zone of the main heater has a large thermal radiation range, which can ensure stable crystal pulling. However, the larger the range of the thermal radiation of the heating zone of the main heater to the quartz crucible, the more severe the reaction between the silicon liquid and the quartz in the quartz crucible (SiO 2 +Si=SiO+O 2 ), increasing the oxygen content in the silicon liquid, resulting in an increase in the oxygen content of the crystal rod. In the prior art, thermal field oxygen reduction is generally achieved by reducing the number of soft felt layers in the furnace bottom insulation to keep the bottom of the crucible at a lower temperature. Although this method has a significant oxygen reduction effect, it is difficult to pull crystals and has a low yield.
[0003] Therefore, there is an urgent need to provide a single crystal furnace that can reduce oxygen without affecting the difficulty of crystal pulling. Utility Model Content
[0004] In view of this, the utility model provides a single crystal furnace, which is used to reduce oxygen without affecting the thermal insulation of the single crystal furnace and the difficulty of crystal pulling.
[0005] The single crystal furnace provided by the utility model comprises: a furnace body, the furnace body comprises a main furnace chamber, and the main furnace chamber comprises:
[0006] A crucible, wherein a crucible rim is provided on the outside of the crucible, and a bottom heater is provided on the outside of the bottom of the crucible rim;
[0007] A main heater, the heating area of the main heater corresponds to the upper part of the crucible, is circumferentially arranged outside the crucible side, and the foot plate of the main heater extends to the bottom of the single crystal furnace;
[0008] The heat preservation barrel is sleeved between the heater and the inner wall of the furnace body. The heat preservation barrel includes an upper heat preservation barrel, a middle heat preservation barrel and a lower heat preservation barrel along a first direction. The first direction is the direction from the top of the single crystal furnace to the bottom of the single crystal furnace. Along the second direction, the middle heat preservation barrel and the lower heat preservation barrel correspond to the crucible side. The second direction intersects with the first direction.
[0009] The auxiliary heat-insulating structure is located between the crucible side and the heat-insulating barrel, and along the first direction, is located on the side of the main heater close to the bottom of the single crystal furnace; the auxiliary heat-insulating structure includes two independently symmetrically arranged arc plates, the foot plate of the main heater is located between the two arc plates, and the side of the arc plate away from the main heater includes a hollow area;
[0010] The bottom of the furnace body includes gas guide holes, and the argon gas entering from the top of the main furnace chamber is discharged through the hollow area and the gas guide holes.
[0011] Optionally, the number of hollow areas is at least 2.
[0012] Optionally, a supporting leg is provided between two adjacent hollow areas, and a lower edge of the supporting leg is flush with a lower edge of the arc-shaped plate.
[0013] Optionally, a side edge of the arc-shaped plate is bent toward a side away from the crucible.
[0014] Optionally, along the extension direction of the arc plate, the length of the hollow area is 80 mm-120 mm.
[0015] Optionally, the height of the hollow area along the first direction is greater than or equal to 100 mm.
[0016] Optionally, along the first direction, a distance between the arc plate and a heating area of the main heater is greater than or equal to 30 mm.
[0017] Optionally, the distance between the arc-shaped plate and the outer wall of the crucible side is greater than or equal to 20 mm.
[0018] Optionally, the distance between the arc plate and the foot plate of the main heater is greater than or equal to 30 mm.
[0019] Optionally, the material of the auxiliary thermal insulation structure is a carbon-carbon composite material.
[0020] Compared with the prior art, the single crystal furnace provided by the utility model achieves at least the following beneficial effects:
[0021] The single crystal furnace of the utility model comprises a furnace body, a main furnace chamber is arranged in the furnace body, the main furnace chamber comprises a crucible, a crucible side, a bottom heater, a main heater and a heat preservation barrel, a crucible side is arranged on the outside of the crucible, and a bottom heater is arranged on the outside of the bottom of the crucible side; a heating zone of the main heater corresponds to the upper part of the crucible, and is arranged on the outside of the crucible side along the circumferential direction, and a foot plate of the main heater extends to the furnace bottom of the single crystal furnace; the heat preservation barrel is sleeved between the heater and the inner wall of the furnace body, and the heat preservation barrel comprises an upper heat preservation barrel, a middle heat preservation barrel and a lower heat preservation barrel along a first direction, and the first direction is the single crystal The top of the furnace points to the direction of the bottom of the single crystal furnace. Along the second direction, the middle insulation barrel and the lower insulation barrel correspond to the crucible side, and the second direction intersects with the first direction; the single crystal furnace of the present application also includes an auxiliary insulation structure, which is clamped between the crucible side and the insulation barrel. Along the first direction, it is located on the side of the main heater close to the bottom of the single crystal furnace. The auxiliary insulation structure includes two independently symmetrically arranged arc plates, the foot plate of the main heater is located between the two arc plates, and the side of the arc plate away from the main heater includes a hollow area; the bottom of the furnace body includes air guide holes. The utility model arranges an auxiliary insulation structure on a side of the main heater close to the bottom of the single crystal furnace. Along the second direction, the auxiliary insulation structure corresponds to the lower part of the crucible, and the main heat radiation area of the main heater corresponds to the upper part of the crucible. In this way, the heat radiation of the main heater to the bottom of the crucible can be reduced, thereby reducing the oxygen content in the silicon liquid. At the same time, since the number of soft felt layers in the bottom insulation is not reduced, the thermal insulation performance of the thermal field is not affected, the heat loss is reduced, and the crystal pulling efficiency is not affected. The side of the arc plate away from the main heater includes a hollow area, and the argon gas entering from the top of the main furnace chamber is discharged through the air guide holes in the hollow area and the bottom of the furnace body, thereby ensuring the smooth flow of the argon gas, ensuring the stability of the crystal pulling process, and the crystal pulling difficulty is small and the output is high.
[0022] Of course, any product implementing the present utility model does not necessarily need to achieve all of the above-mentioned technical effects at the same time.
[0023] Other features and advantages of the present invention will become apparent from the following detailed description of exemplary embodiments of the present invention with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the present invention and, together with the description, serve to explain the principles of the present invention.
[0025] Figure 1 It is a structural schematic diagram of a single crystal furnace provided by the utility model;
[0026] Figure 2 This is a structural schematic diagram of another single crystal furnace provided by the utility model;
[0027] Figure 3 It is a structural schematic diagram of an auxiliary thermal insulation structure provided by the utility model;
[0028] Figure 4 It is a top view of the bottom of the single crystal furnace provided by the utility model. DETAILED DESCRIPTION
[0029] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that unless otherwise specifically stated, the relative arrangements of components and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention.
[0030] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the present invention, its application, or uses.
[0031] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered as part of the specification.
[0032] In all examples shown and discussed herein, any specific values should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.
[0033] It should be noted that like reference numerals and letters refer to similar items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.
[0034] Reference Figure 1 , Figure 2 , Figure 3 and Figure 4 , Figure 1 This is a structural schematic diagram of a single crystal furnace provided by the utility model. Figure 2 This is a structural schematic diagram of another single crystal furnace provided by the utility model. Figure 1 The crucible and the crucible side are shown in FIG. Figure 2 The crucible and the crucible side are not shown. Figure 3 This is a structural schematic diagram of an auxiliary thermal insulation structure provided by the utility model. Figure 4 It is a top view of the bottom of the single crystal furnace provided by the utility model.
[0035] Combination Figures 1 to 4 The single crystal furnace includes: a furnace body 10, the furnace body 10 includes a main furnace chamber 20, and the main furnace chamber 20 includes a crucible 30, a crucible side 40, a main heater 60, a bottom heater 50, a heat preservation barrel 70 and an auxiliary heat preservation structure 80.
[0036] A crucible 30, a crucible side 40 is disposed on the outside of the crucible 30, and a bottom heater 50 is disposed on the outside of the bottom of the crucible side 40;
[0037] A main heater 60, wherein a heating zone 601 of the main heater 60 corresponds to an upper portion of the crucible 30, and is circumferentially disposed outside the crucible side 40, and a foot plate 602 of the main heater 60 extends to the bottom of the single crystal furnace;
[0038] The insulation barrel 70 is sleeved between the heater and the inner wall of the furnace body 10. The upper insulation barrel 701 includes an upper insulation barrel 701, a middle insulation barrel 702 and a lower insulation barrel 703 along a first direction X. The first direction X is a direction from the top of the single crystal furnace to the bottom of the single crystal furnace. Along the second direction Y, the middle insulation barrel 702 and the lower insulation barrel 703 correspond to the crucible side 40. The second direction Y intersects with the first direction X.
[0039] The auxiliary insulation structure 80 is located between the crucible side 40 and the insulation barrel 70, and is located on the side of the main heater 60 close to the bottom of the single crystal furnace along the first direction X; the auxiliary insulation structure 80 includes two independently symmetrically arranged arc plates 801, the foot plate 602 of the main heater 60 is located between the two arc plates 801, and the side of the arc plate 801 away from the main heater 60 includes a hollow area 802,
[0040] The bottom of the furnace body 10 includes a gas guide hole 90 , and the argon gas entering from the top of the main furnace chamber 20 is discharged through the hollow area 802 and the gas guide hole 90 .
[0041] Specifically, the single crystal furnace includes a furnace body 10, and of course the single crystal furnace also includes an electrical part, a water cooling system, a vacuum system and a thermal system, which are not specifically limited here, and the utility model only limits the furnace body 10 part. The furnace body 10 includes a main furnace chamber 20, and of course the furnace body 10 also includes a sub-chamber 5, which is located on the side of the main furnace chamber 20 away from the bottom of the furnace body 10, and a lifting head is also provided on the side of the sub-chamber 5 away from the main furnace chamber 20. The main furnace chamber 20 includes a crucible 30, a crucible side 40, a main heater 60, a bottom heater 50, a heat preservation barrel 70 and an auxiliary heat preservation structure 80.
[0042] The crucible 30 is provided with a crucible side 40 on the outside, and a bottom heater 50 is provided on the outside of the bottom of the crucible side 40. The crucible 30 is used to hold polycrystalline silicon materials. The polycrystalline silicon raw materials are melted in a single crystal furnace, and then a seed crystal specified on the seed crystal axis is inserted into the melt surface. After the seed crystal and the melt are fully fused, the seed crystal is slowly pulled upward, and the crystal grows at the lower end of the seed crystal. After the processes of seeding, shoulder release / shoulder rotation, equal diameter, and tailing, a single crystal can be produced. Figure 1 and Figure 2The crucible 30 is provided with a pull rod 2 at the bottom of the crucible 30, and the pull rod 2 passes through the bottom of the furnace body 10. The lifting and lowering of the pull rod 2 can adjust the height of the crucible 30. The bottom heater 50 is located on the side of the bottom of the crucible 40 near the bottom of the furnace body 10. The shape of the bottom heater 50 can be seen in FIG. Figure 4 The bottom heater 50 is arranged in a serpentine shape, and electrodes are connected to the two ends of the bottom heater 50. When powered on, the bottom of the crucible 30 can be heated. Of course, during the crystal pulling process, the bottom heater 50 is turned off.
[0043] The heating zone 601 of the main heater 60 is provided with a heating plate 6011, which is connected end to end to form a ring, and the two ends of the heating plate 6011 are connected with foot plates 602, and the foot plates 602 of the main heater 60 extend to the bottom of the single crystal furnace, and the bottom of the furnace is provided with a heating electrode 3, and the foot plates 602 of the main heater 60 are electrically connected to the heating electrode 3. The heating zone 601 of the main heater 60 corresponds to the upper part of the crucible 30 and is arranged on the outer side of the crucible side 40 along the circumferential direction, that is, the heating plate 6011 is arranged on the outer side of the crucible side 40 to heat the upper part of the crucible 30. When pulling crystals, the main heater 60 is turned on and the bottom heater 50 is turned off. In this embodiment, the heating zone 601 of the main heater 60 corresponds to the upper part of the crucible 30, which means that along the second direction Y (the second direction Y intersects with the first direction X), the heating zone 601 of the main heater 60 at least overlaps with the upper part of the crucible 30. Of course, the upper surface of the main heater 60 may be higher than the upper surface of the crucible 30, thereby ensuring that the upper part of the crucible 30 is sufficiently heated.
[0044] When the single crystal silicon rod is straightened by the Czochralski method, it is necessary to use insulation material to wrap the outer periphery of the heater to prevent heat loss and reduce the power consumption of the heater. The utility model arranges an insulation barrel 70 between the heater and the inner wall of the furnace body 10. The insulation barrel 70 is an annular cylindrical structure. The upper insulation barrel 701 includes an upper insulation barrel 701, a middle insulation barrel 702 and a lower insulation barrel 703 along the first direction X. The first direction X is the direction from the top of the single crystal furnace to the bottom of the single crystal furnace. Along the second direction Y, the middle insulation barrel 702 and the lower insulation barrel 703 correspond to the crucible side 40, and the upper insulation barrel 701 corresponds to the heat shield 1, that is, along the second direction Y, the upper insulation barrel 701 overlaps with the heat shield 1, part of the middle insulation barrel 702 overlaps with the crucible side 40 and the heating area 601 of the main heater 60, and part of the lower insulation barrel 703 overlaps with the crucible side 40, thereby achieving overall insulation and ensuring insulation performance.
[0045] The auxiliary insulation structure 80 is located between the crucible side 40 and the insulation barrel 70, along the first direction X, on the side of the main heater 60 close to the bottom of the single crystal furnace; the auxiliary insulation structure 80 includes two independently symmetrically arranged arc plates 801, the curvature of the arc plates 801 can be consistent with the arc of the insulation barrel 70, the two arc plates 801 are not connected, but separated from each other, and there is a certain interval between the two arc plates 801, and the foot plate 602 of the main heater 60 is located between the two arc plates 801 to avoid affecting the normal use of the main heater 60. The side of the arc plate 801 away from the main heater 60 includes a hollow area 802. An auxiliary insulation structure 80 is arranged on the side of the main heater 60 close to the bottom of the single crystal furnace. Along the second direction Y, the auxiliary insulation structure 80 corresponds to the lower part of the crucible 30, and the main heat radiation area of the main heater 60 corresponds to the upper part of the crucible 30. In this way, the auxiliary insulation structure 80 will isolate the heat radiation of the main heater 60 to the bottom of the crucible 30, which can reduce the heat radiation of the main heater 60 to the bottom of the crucible 30, thereby reducing the oxygen content in the silicon liquid. At the same time, since the number of soft felt layers in the bottom insulation is not reduced, the thermal insulation of the heat field is not affected, the heat loss is reduced, and the crystal pulling efficiency is not affected.
[0046] It should be noted that, refer to Figure 3 In this embodiment, the hollow area 802 can be set close to the lower edge of the arc plate 801, or the lower edge of the hollow area 802 can have a certain distance from the lower edge of the arc plate 801 (not shown in the figure), which is not specifically limited here, as long as the hollow area 802 for circulating argon gas is set on the side of the arc plate 801 away from the main heater 60. Of course, the shape of the hollow area 802 is not specifically limited here, for example, the hollow area 802 can be square, round, oval, etc.
[0047] Reference Figure 4 The bottom of the furnace body 10 includes an air guide hole 90, and the argon gas entering from the top of the main furnace chamber 20 is discharged through the hollow area 802 and the air guide hole 90. The air guide hole 90 arranged at the bottom of the furnace body 10 is connected to the exhaust pipe (not shown in the figure), and the exhaust pipe is connected to the pump (not shown). When the pump is started, the argon gas injected from the top of the main furnace chamber 20 is extracted from the path from the top to the air guide hole 90. Of course, the argon gas flows through the space between the inner wall of the insulation barrel 70 and the outer side of the crucible 40. When the argon gas passes through the lower insulation barrel 703 and the auxiliary insulation structure 80, since the side of the arc plate 801 of the auxiliary insulation structure 80 away from the main heater 60 includes a hollow area 802, the argon gas will pass through the hollow area 802 to enter the air guide hole 90 and then be discharged from the furnace body 10. The argon gas is used for heat dissipation of the crystal rod 4, and can also take away volatiles, and as a protective gas, the smooth discharge of the argon gas can ensure the quality and efficiency of crystal pulling.
[0048] In some optional embodiments, continue to refer to Figures 1 to 3, the number of hollow areas 802 is at least 2.
[0049] Optionally, the number of hollow areas 802 in each arc-shaped plate 801 may be 2, 3, or 4, or may be other numbers, which are not specifically limited here.
[0050] It is understandable that if the lower edge of the hollow area 802 coincides with the lower edge of the arc plate 801, if the number of the hollow area 802 is only one, then there will be a problem that the arc plate 801 is unstable and easy to fall over after being placed. In this embodiment, the number of hollow areas 802 in each arc plate 801 is at least 2. The more the number of hollow areas 802, the lower edge of the arc plate 801 between the two hollow areas 802 will form a support, thereby preventing the arc plate 801 from falling over. On the other hand, the more the number of hollow areas 802, the larger the total area of the hollow areas 802, the more conducive to the smooth passage of argon gas, and will not affect the crystal pulling yield.
[0051] In some optional embodiments, continue to refer to Figure 3 A supporting leg 803 is provided between two adjacent hollow areas 802 , and the lower edge of the supporting leg 803 is flush with the lower edge of the arc plate 801 .
[0052] from Figure 3 It can be seen that the lower edge of the hollow area 802 is flush with the lower edge of the curved plate 801, and a supporting leg 803 is provided between the two hollow areas 802. If the lower edge of the supporting leg 803 and the lower edge of the curved plate 801 are no longer on the same horizontal plane, the curved plate 801 will fall over after installation due to the uneven lower surface.
[0053] In this embodiment, a support leg 803 is provided between two adjacent hollow areas 802, and the lower edge of the support leg 803 is flush with the lower edge of the arc plate 801. The support leg 803 plays a role in supporting the arc plate 801, thus preventing the arc plate 801 from tipping over.
[0054] In some optional embodiments, continue to refer to Figures 1 to 3 The side edge 8011 of the arc-shaped plate 801 is bent toward a side away from the crucible 30 .
[0055] It can be understood that the side edge 8011 of the arc plate 801 is turned outward, specifically bent toward the side away from the crucible 30. At this time, the extension direction of the arc plate 801 intersects with the side edge 8011, so that the main body of the arc plate 801 and the side edge 8011 of the arc plate 801 form an angle. At this time, the side edge 8011 of the arc plate 801 also plays a supporting role, which can prevent the arc plate 801 from tipping over.
[0056] Of course, the width of the side edge 8011 of the arc plate 801 is not specifically limited here. The larger the width of the side edge 8011 of the arc plate 801, the more stable the arc plate 801 is, and the less likely the arc plate 801 is to tip over. However, since the arc plate 801 is placed between the crucible side 40 and the insulation tube, and is limited by the distance between the crucible side 40 and the insulation tube, the width of the edge of the arc plate 801 cannot be greater than the distance between the crucible side 40 and the insulation tube.
[0057] In some optional embodiments, continue to refer to Figures 1 to 3 , along the extension direction of the arc plate 801, the length of the hollow area 802 is 80mm-120mm.
[0058] Optionally, along the extension direction of the arc-shaped plate 801, the length of the hollow area 802 can be 80 mm, 85 mm, 90 mm, 95 mm, 100 mm, 105 mm, 110 mm, 115 mm or 120 mm, and of course can also be any value between 80 mm and 120 mm, which is not specifically limited here. It should be noted that when the number of the hollow areas 802 is 2, the length of the hollow area 802 here refers to the total length of the two hollow areas 802.
[0059] It is understandable that the length of the hollow area 802 along the extension direction of the arc plate 801 cannot be too large or too small. If the length of the hollow area 802 along the extension direction of the arc plate 801 is too large, when the height of the hollow area 802 along the first direction X is constant, the area of the hollow area 802 will be too large, and the area without the hollow area 802 will be too small, and the arc plate 801 will easily fall over. If the length of the hollow area 802 along the extension direction of the arc plate 801 is too small, when the height of the hollow area 802 along the first direction X is constant, the area of the hollow area 802 will be too small, which will limit the smooth passage of argon from the hollow area 802. Once the amount of argon passing through is reduced, the crystal pulling yield will be affected.
[0060] In this embodiment, along the extension direction of the arc plate 801, the length of the hollow area 802 is 80 mm-120 mm, which will neither cause the arc plate 801 to fall over nor affect the smooth passage of argon gas and the crystal pulling output.
[0061] In some optional embodiments, continue to refer to Figures 1 to 3 , the height of the hollow area 802 along the first direction X is greater than or equal to 100 mm.
[0062] Optionally, the height of the hollow area 802 along the first direction X may be 100 mm, 102 mm, 104 mm, 106 mm, 108 mm, 110 mm, etc., which is not specifically limited here.
[0063] It can be understood that the height of the hollow area 802 along the first direction X cannot be too small. If the height of the hollow area 802 along the first direction X is too small, the area of the hollow area 802 will be too small, which will limit the smooth passage of argon gas through the hollow area 802. Once the argon gas flow rate is reduced, it will affect the crystal pulling output.
[0064] In this embodiment, the height of the hollow area 802 along the first direction X is greater than or equal to 100 mm, which will not affect the smooth passage of argon gas and the crystal pulling yield. Of course, the height of the hollow area 802 along the first direction X cannot be too large. If the height in the first direction X is too large, the overall isolation and heat preservation effect of the auxiliary heat preservation structure 80 will be reduced.
[0065] In some optional embodiments, continue to refer to Figure 2 , along the first direction X, the distance between the arc plate 801 and the heating area 601 of the main heater 60 is greater than or equal to 30 mm.
[0066] It can be understood that along the first direction X, the distance between the upper edge of the arc plate 801 and the lower edge of the heating plate 6011 of the main heater 60 cannot be too small. If the distance between the upper edge of the arc plate 801 and the lower edge of the heating plate 6011 of the main heater 60 is too small, when the main heater 60 is powered on for heating, it is easy to ignite with the main heater 60.
[0067] In this embodiment, along the first direction X, the distance between the arc plate 801 and the heating zone 601 of the main heater 60 is greater than or equal to 30 mm. For example, the distance between the arc plate 801 and the heating zone 601 of the main heater 60 is 30 mm, 32 mm, 34 mm, 36 mm, 38 mm, 40 mm, etc., which can prevent sparks from occurring with the main heater 60.
[0068] On the other hand, along the first direction X, the distance between the arc plate 801 and the heating zone 601 of the main heater 60 cannot be too large. If the distance between the arc plate 801 and the heating zone 601 of the main heater 60 is too large, the heating zone 601 of the main heater 60 will radiate heat to the bottom of the crucible 30, that is, it will affect the effect of reducing the heat radiation of the main heater 60 to the bottom of the crucible 30.
[0069] In some optional embodiments, continue to refer to Figure 1 The distance between the arc plate 801 and the outer wall of the crucible side 40 is greater than or equal to 20 mm.
[0070] The distance between the arc plate 801 and the outer wall of the crucible side 40 cannot be too small. If the distance between the inner wall of the arc plate 801 and the outer wall of the crucible side 40 is too small, it will affect the melting of the polysilicon material. In this embodiment, the distance between the arc plate 801 and the outer wall of the crucible side 40 is greater than or equal to 20 mm, for example, it can be 20 mm, 22 mm, 24 mm, 26 mm, 28 mm, 30 mm, etc., to avoid affecting the melting of the polysilicon material. Of course, since the arc plate 801 is arranged between the crucible side 40 and the insulation tube, it is limited by the distance between the crucible side 40 and the insulation tube, so the distance between the arc plate 801 and the outer wall of the crucible side 40 cannot be too large.
[0071] In some optional embodiments, continue to refer to Figure 4 The distance between the arc plate 801 and the foot plate 602 of the main heater 60 is greater than or equal to 30 mm.
[0072] Optionally, the distance between the arc plate 801 and the foot plate 602 of the main heater 60 can be 30 mm, 32 mm, 34 mm, 36 mm, 38 mm, 40 mm, etc., which is not specifically limited here.
[0073] It can be understood that when the main heater 60 is working, the current is input through the heating electrode 3 at the bottom of the furnace bottom, and is transmitted to the heating plate 6011 of the heating area 601 of the main heater 60 through the foot plate 602 of the main heater 60. If the current passes through the foot plate 602 of the main heater 60, if the distance between the arc plate 801 and the foot plate 602 of the main heater 60 is too small, when the main heater 60 is powered on for heating, it is easy to ignite with the main heater 60.
[0074] In this embodiment, the distance between the arc plate 801 and the foot plate 602 of the main heater 60 is greater than or equal to 30 mm, which can avoid sparks with the main heater 60.
[0075] In some optional embodiments, continue to refer to Figure 3 The material of the auxiliary thermal insulation structure 80 is a carbon-carbon composite material.
[0076] It is understandable that the carbon-carbon composite material has a relatively high strength. The auxiliary thermal insulation structure 80 is made of a carbon-carbon composite material, which can maximize its strength and thereby ensure the service life of the auxiliary thermal insulation structure 80 .
[0077] It can be seen from the above embodiments that the single crystal furnace provided by the utility model achieves at least the following beneficial effects:
[0078] The single crystal furnace of the utility model comprises a furnace body, a main furnace chamber is arranged in the furnace body, the main furnace chamber comprises a crucible, a crucible side, a bottom heater, a main heater and a heat preservation barrel, a crucible side is arranged on the outside of the crucible, and a bottom heater is arranged on the outside of the bottom of the crucible side; a heating zone of the main heater corresponds to the upper part of the crucible, and is arranged on the outside of the crucible side along the circumferential direction, and a foot plate of the main heater extends to the furnace bottom of the single crystal furnace; the heat preservation barrel is sleeved between the heater and the inner wall of the furnace body, and the heat preservation barrel comprises an upper heat preservation barrel, a middle heat preservation barrel and a lower heat preservation barrel along a first direction, and the first direction is the single crystal The top of the furnace points to the direction of the bottom of the single crystal furnace. Along the second direction, the middle insulation barrel and the lower insulation barrel correspond to the crucible side, and the second direction intersects with the first direction; the single crystal furnace of the present application also includes an auxiliary insulation structure, which is clamped between the crucible side and the insulation barrel. Along the first direction, it is located on the side of the main heater close to the bottom of the single crystal furnace. The auxiliary insulation structure includes two independently symmetrically arranged arc plates, the foot plate of the main heater is located between the two arc plates, and the side of the arc plate away from the main heater includes a hollow area; the bottom of the furnace body includes air guide holes. The utility model arranges an auxiliary insulation structure on a side of the main heater close to the bottom of the single crystal furnace. Along the second direction, the auxiliary insulation structure corresponds to the lower part of the crucible, and the main heat radiation area of the main heater corresponds to the upper part of the crucible. In this way, the heat radiation of the main heater to the bottom of the crucible can be reduced, thereby reducing the oxygen content in the silicon liquid. At the same time, since the number of soft felt layers in the bottom insulation is not reduced, the thermal insulation performance of the thermal field is not affected, the heat loss is reduced, and the crystal pulling efficiency is not affected. The side of the arc plate away from the main heater includes a hollow area, and the argon gas entering from the top of the main furnace chamber is discharged through the air guide holes in the hollow area and the bottom of the furnace body, thereby ensuring the smooth flow of the argon gas, ensuring the stability of the crystal pulling process, and the crystal pulling difficulty is small and the output is high.
[0079] Although some specific embodiments of the present invention have been described in detail by way of examples, it should be understood by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present invention. It should be understood by those skilled in the art that the above embodiments may be modified without departing from the scope and spirit of the present invention. The scope of the present invention is defined by the appended claims.
Claims
1. A single crystal furnace, characterized in that: include: The furnace body includes a main furnace chamber, and the main furnace chamber includes: A crucible, wherein a crucible rim is disposed on the outside of the crucible, and a bottom heater is disposed on the outside of the bottom of the crucible rim; A main heater, wherein the heating area of the main heater corresponds to the upper part of the crucible, is circumferentially arranged outside the crucible side, and the foot plate of the main heater extends to the bottom of the single crystal furnace; an insulation barrel, which is sleeved between the heater and the inner wall of the furnace body, wherein the insulation barrel includes an upper insulation barrel, a middle insulation barrel and a lower insulation barrel along a first direction, wherein the first direction is a direction from the top of the single crystal furnace to the bottom of the single crystal furnace, and along a second direction, the middle insulation barrel and the lower insulation barrel correspond to the crucible side, and the second direction intersects with the first direction; The auxiliary heat-insulating structure is located between the crucible side and the heat-insulating barrel, and along the first direction, is located on the side of the main heater close to the bottom of the single crystal furnace; the auxiliary heat-insulating structure comprises two independently symmetrically arranged arc plates, the foot plate of the main heater is located between the two arc plates, and the side of the arc plate away from the main heater comprises a hollow area; The bottom of the furnace body comprises a gas guide hole, and the argon gas entering from the top of the main furnace chamber is discharged through the hollow area and the gas guide hole.
2. The single crystal furnace according to claim 1, characterized in that: The number of the hollow areas is at least 2.
3. The single crystal furnace according to claim 2, characterized in that: A supporting leg is provided between two adjacent hollow areas, and the lower edge of the supporting leg is flush with the lower edge of the arc-shaped plate.
4. The single crystal furnace according to claim 1, characterized in that: The side edge of the arc-shaped plate is bent toward a side away from the crucible.
5. The single crystal furnace according to claim 1, characterized in that: Along the extending direction of the arc-shaped plate, the length of the hollow area is 80 mm-120 mm.
6. The single crystal furnace according to claim 1, characterized in that: The height of the hollow area along the first direction is greater than or equal to 100 mm.
7. The single crystal furnace according to claim 1, characterized in that: Along the first direction, a distance between the arc plate and a heating area of the main heater is greater than or equal to 30 mm.
8. The single crystal furnace according to claim 1, characterized in that: The distance between the arc-shaped plate and the outer wall of the crucible side is greater than or equal to 20 mm.
9. The single crystal furnace according to claim 1, characterized in that: The distance between the arc plate and the foot plate of the main heater is greater than or equal to 30 mm.
10. The single crystal furnace according to claim 1, characterized in that: The auxiliary thermal insulation structure is made of a carbon-carbon composite material.