Single crystal furnace

Abstract

The utility model provides a single crystal furnace, and relates to the field of photovoltaic technology, the single crystal furnace comprises a thermal field structure, the thermal field structure comprises an upper thermal insulation cylinder, a lower thermal insulation cylinder, a heater and at least two heater foot plates; the lower heat insulation cylinder is located below the upper heat insulation cylinder, the heater is located on the inner side of the upper heat insulation cylinder, the inner diameter of the lower heat insulation cylinder is smaller than that of the upper heat insulation cylinder, the upper heat insulation cylinder comprises a first receding opening, the lower heat insulation cylinder comprises a second receding opening, and a heater foot plate penetrates through the first receding opening and the second receding opening. A first avoiding opening and a second avoiding opening are formed, so that a heater foot plate can conveniently pass through; the arrangement of the upper heat insulation cylinder blocks a channel for the heater to radiate and dissipate heat towards the outside of the upper heat insulation cylinder, thereby being beneficial to improving the heat preservation effect and reducing the heat loss, thereby being beneficial to improving the per unit yield of the silicon single crystal rod, and meanwhile, the arrangement of the lower heat insulation cylinder is beneficial to blocking a channel for the heater to radiate heat downwards and reducing the temperature in the lower heat insulation cylinder. Therefore, the oxygen content in the silicon single crystal rod can be reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of photovoltaics, and more specifically, to a single crystal furnace. Background Art

[0002] In the production process of single crystal silicon rods for solar photovoltaics, a graphite heater is used to heat and melt polysilicon materials, and then single crystal silicon rods are formed through recrystallization. In the production process of single crystal silicon rods, improving the single output of single crystal silicon rods and reducing the oxygen content in single crystal silicon rods are a pair of contradictions. High single output often comes with high oxygen content.

[0003] The heating performance of the graphite heater has an important impact on the single output and oxygen content of single crystal silicon rods. A heater with high calorific value and large heating area can keep the crystallization of the crystal rod stable and bring high single output. However, at the same time, the high temperature allows oxygen elements in the crucible to enter the silicon liquid, resulting in an increase in the oxygen content of the crystal rod.

[0004] Therefore, how to reduce the oxygen content in single crystal silicon rods while improving the single output has become one of the technical problems to be solved urgently at present. Summary of the Utility Model

[0005] In view of this, the utility model provides a single crystal furnace. By improving the internal heat field structure of the single crystal furnace and guiding heat, it is possible to reduce the oxygen content in the single crystal silicon rod while improving the single output of the single crystal silicon rod.

[0006] The present application provides a single crystal furnace, including a heat field structure, and the heat field structure includes an upper heat insulation cylinder, a lower heat insulation cylinder, a heater, and at least two heater foot plates;

[0007] Along a first direction, the lower heat insulation cylinder is located below the upper heat insulation cylinder, and the first direction is the height direction of the heat field structure;

[0008] The heater is located inside the upper heat insulation cylinder, and the connection part of the heater is connected to the heater foot plate; the upper heat insulation cylinder is located on the side of the connection part away from the heater, and the lower heat insulation cylinder is located inside the heater foot plate;

[0009] Both the upper heat insulation cylinder and the lower heat insulation cylinder are cylindrical, and the inner diameter of the lower heat insulation cylinder is smaller than the inner diameter of the upper heat insulation cylinder;

[0010] The upper heat insulation cylinder includes a first avoidance opening, the lower heat insulation cylinder includes a second avoidance opening, and the heater foot plate passes through the first avoidance opening and the second avoidance opening.

[0011] Optionally, among them:

[0012] The heater foot plate further includes a connection bridge, a support leg, and a base;

[0013] The connecting bridge is perpendicularly connected to the connecting part. Along the first direction, the connecting bridge is located on the side of the connecting part closer to the lower heat insulation cylinder. Along the second direction, the connecting bridge is located on the side of the connecting part away from the heater, and the second direction is the thickness direction of the support leg.

[0014] The support leg is perpendicularly connected to the connecting bridge. Along the first direction, the support leg is located on the side of the connecting bridge away from the connecting part. Along the second direction, the support leg is located on the side of the connecting bridge away from the connecting part.

[0015] The base is perpendicularly connected to the support leg. Along the first direction, the base is located on the side of the support leg away from the connecting bridge. Along the second direction, the base is located on the side of the support leg closer to the connecting part.

[0016] Optionally, where:

[0017] It further includes an electrode. The electrode is correspondingly arranged with the heater foot plate. The electrode is located on the side of the base of the heater foot plate away from the connecting bridge, and the electrode is connected to the base through an electrode bolt.

[0018] Optionally, where:

[0019] The inner diameter of the lower heat insulation cylinder is smaller than the inner diameter of the heater.

[0020] Optionally, where:

[0021] It further includes a first outward flange. The first outward flange is located on the side of the lower heat insulation cylinder closer to the upper heat insulation cylinder. The first outward flange connects the lower heat insulation cylinder and the upper heat insulation cylinder.

[0022] Optionally, where:

[0023] It further includes a second outward flange. The second outward flange is located on the side of the upper heat insulation cylinder away from the lower heat insulation cylinder.

[0024] Optionally, where:

[0025] It further includes a heat preservation barrel. The heat preservation barrel is located outside the upper heat insulation cylinder and the lower heat insulation cylinder, and the second outward flange is in contact with the inner wall of the heat preservation barrel.

[0026] Optionally, where:

[0027] It further includes a crucible ring and a crucible support. Along the first direction, the crucible support is located below the crucible ring. The crucible ring is located inside the heater and the lower heat insulation cylinder.

[0028] Optionally, where:

[0029] It further includes a crucible support rod, and the crucible support rod is located on the side of the crucible support away from the crucible wall.

[0030] Optionally, among them:

[0031] It further includes a crucible, and the crucible is located in the accommodation space formed by the crucible wall and the crucible support.

[0032] Compared with the prior art, a single crystal furnace provided by the present utility model at least achieves the following beneficial effects:

[0033] The present application provides a single crystal furnace, including a thermal field structure. Among them, the thermal field structure includes an upper heat insulation cylinder, a lower heat insulation cylinder, a heater, and at least two heater foot plates; wherein, the lower heat insulation cylinder is located below the upper heat insulation cylinder, the heater is located inside the upper heat insulation cylinder, both the upper heat insulation cylinder and the lower heat insulation cylinder are cylindrical, the inner diameter of the lower heat insulation cylinder is smaller than that of the upper heat insulation cylinder, the upper heat insulation cylinder includes a first avoidance opening, the lower heat insulation cylinder includes a second avoidance opening, and the heater foot plate passes through the first avoidance opening and the second avoidance opening. The settings of the first avoidance opening and the second avoidance opening facilitate the passage of the heater foot plate; the setting of the upper heat insulation cylinder blocks the heat radiation channel of the heater to the outside of the upper heat insulation cylinder, which is beneficial to improving the heat preservation effect and reducing heat loss, thereby being beneficial to improving the single output of the single crystal rod. At the same time, the setting of the lower heat insulation cylinder is beneficial to blocking the heat radiation channel of the heater downward, which is beneficial to reducing the temperature inside the lower heat insulation cylinder, and thus is beneficial to reducing the oxygen content in the single crystal rod.

[0034] Of course, it is not necessarily required that any product implementing the present utility model simultaneously achieves all of the above technical effects.

[0035] Through the following detailed description of the exemplary embodiments of the present utility model with reference to the accompanying drawings, other features and advantages of the present utility model will become clear. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The drawings incorporated in the specification and constituting a part of the specification illustrate embodiments of the present utility model and, together with the description, are used to explain the principles of the present utility model.

[0037] Figure 1 Shown is a schematic diagram of a thermal field structure provided by an embodiment of the present application;

[0038] Figure 2 Shown is a schematic diagram of another thermal field structure provided by an embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0039] 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.

[0040] 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.

[0041] 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 part of the specification.

[0042] 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.

[0043] 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.

[0044] The inventors found in their research that in the production process of single crystal silicon rods, increasing the yield of single crystal silicon rods and reducing the oxygen content in the single crystal silicon rods are a pair of contradictions. High yield is often accompanied by high oxygen content. The heating performance of the graphite heater has an important influence on the yield and oxygen content of the single crystal silicon rod. Heaters with high heat output and large heating area can maintain the crystallization stability of the crystal rod and bring high yield, but at the same time, high temperature allows oxygen elements in the crucible to enter the silicon liquid, resulting in an increase in the oxygen content of the crystal rod.

[0045] Therefore, how to reduce the oxygen content in single crystal silicon rods while increasing the yield has become one of the technical problems that need to be solved urgently at this stage.

[0046] In view of this, the utility model provides a single crystal furnace, which conducts heat by improving the thermal field structure in the single crystal furnace, thereby achieving the goal of increasing the yield of single crystal silicon rods and reducing the oxygen content in the single crystal silicon rods.

[0047] The following is a detailed description with reference to the accompanying drawings and specific embodiments.

[0048] Figure 1 The figure shows a schematic diagram of a thermal field structure provided in an embodiment of the present application. Please refer to Figure 1 , the embodiment of the present application provides a single crystal furnace, including a thermal field structure 100, the thermal field structure 100 includes an upper thermal insulation tube 10, a lower thermal insulation tube 20, a heater 30 and at least two heater foot plates 40;

[0049] Along the first direction D1, the lower heat insulation cylinder 20 is located below the upper heat insulation cylinder 10, and the first direction D1 is the height direction of the heat field structure 100;

[0050] The heater 30 is located inside the upper heat insulation cylinder 10, and the connection part 41 of the heater 30 and the heater foot plate 40 is connected; the upper heat insulation cylinder 10 is located on the side of the connection part 41 away from the heater 30, and the lower heat insulation cylinder 20 is located inside the heater foot plate 40;

[0051] Both the upper heat insulation cylinder 10 and the lower heat insulation cylinder 20 are cylindrical, and the inner diameter of the lower heat insulation cylinder 20 is smaller than the inner diameter of the upper heat insulation cylinder 10;

[0052] The upper heat insulation cylinder 10 includes a first avoidance opening 11, and the lower heat insulation cylinder 20 includes a second avoidance opening 22. The heater foot plate 40 passes through the first avoidance opening 11 and the second avoidance opening 22.

[0053] Specifically, the present application provides a single crystal furnace. The single crystal furnace includes a heat field structure 100, and the heat field structure 100 includes an upper heat insulation cylinder 10, a lower heat insulation cylinder 20, a heater 30, and at least two heater foot plates 40. Among them, the upper heat insulation cylinder 10 includes a first heat insulation space 101, and the lower heat insulation cylinder 20 includes a second heat insulation space 202. The first heat insulation space 101 and the second heat insulation space 202 are communicated. The upper heat insulation cylinder 10 and the lower heat insulation cylinder 20 are arranged along the first direction D1, and the central axes of the upper heat insulation cylinder 10 and the lower heat insulation cylinder 20 coincide. As shown in the Figure 1 viewing angle, the lower heat insulation cylinder 20 is located below the upper heat insulation cylinder 10, and the heater 30 is located in the first heat insulation space 101 of the upper heat insulation cylinder 10. The setting of the upper heat insulation cylinder 10 is beneficial to preventing the heat of the heater 30 from radiating outside the upper heat insulation cylinder 10, which is beneficial to improving the heat preservation effect and reducing heat loss, and thus is beneficial to improving the single output of the single crystal rod. In the present application, the inner diameter of the lower heat insulation cylinder 20 is set to be smaller than the inner diameter of the upper heat insulation cylinder 10, that is, the channel for the heat of the heater 30 to radiate into the lower heat insulation cylinder 20 along the first direction D1 becomes narrower. That is, a part of the channel for the heat of the heater 30 to radiate into the lower heat insulation cylinder 20 is blocked, so the heat radiating into the lower heat insulation cylinder 20 is reduced, which is beneficial to reducing the temperature in the lower heat insulation cylinder 20, and thus is beneficial to reducing the oxygen content in the single crystal rod. The upper heat insulation cylinder 10 of the present application includes a first avoidance opening 11, and the lower heat insulation cylinder 20 includes a second avoidance opening 22. The settings of the first avoidance opening 11 and the second avoidance opening 22 facilitate the passage of the heater foot plate 40. The number of the first avoidance openings 11 corresponds to the number of the heater foot plates 40, and the number of the second avoidance openings 22 also corresponds to the number of the heater foot plates 40. The heater foot plate 40 is connected to the heater 30.

[0054] In the related art, heaters with high heat generation and large heating areas can maintain the crystallization stability of the crystal bar, resulting in high single production. However, the high temperature allows oxygen elements in the crucible to enter the silicon melt, leading to an increase in the oxygen content of the single crystal silicon bar. It can be understood that the upper heat insulation cylinder 10 in the present application is beneficial to reducing the heat radiation of the heater 30 to the outside of the upper heat insulation cylinder 10, which is beneficial to reducing heat loss, and thus beneficial to improving the single production of the single crystal silicon bar; the lower heat insulation cylinder 20 in the present application is beneficial to reducing the heat radiation channel of the heater 30 into the lower heat insulation cylinder 20, which is beneficial to reducing the temperature inside the lower heat insulation cylinder 20 and reducing the entry of oxygen elements of the crucible into the silicon melt due to high temperature, and thus beneficial to reducing the oxygen content of the single crystal silicon bar; by improving the internal heat field structure 100 of the single crystal furnace in the present application and guiding the heat, it is possible to reduce the oxygen content in the single crystal silicon bar while improving the single production of the single crystal silicon bar. Among them, the single production of the single crystal silicon bar referred to in the present application refers to the production or output of the single crystal silicon bar per unit time.

[0055] It should also be noted that the drawings shown in the present application are only schematic and do not represent their actual sizes and actual structures.

[0056] Figure 2 Shown is a schematic diagram of another heat field structure provided by an embodiment of the present application. Please refer to Figure 1 and Figure 2 , in the heat field structure 100, it further includes a crucible support 51 and a crucible carrier 52. In the perspective shown in the drawing, along the first direction D1, the crucible carrier 52 is located below the crucible support 51, the crucible support 51 is located inside the heater 30 and the lower heat insulation cylinder 20, at least part of the crucible support 51 is located in the first heat insulation space 101 of the upper heat insulation cylinder 10, and at least part of the crucible support 51 is located in the second heat insulation space 202 of the lower heat insulation cylinder 20. The inside of the crucible support 51 is used to install a crucible for holding silicon melt, and the heat of the heater 30 is transferred to the crucible through the crucible support 51. Along the first direction D1, the heater 30 is located on the side close to the entrance of the crucible support 51, and the lower heat insulation cylinder 20 is located on the side far from the entrance of the crucible support 51. An upper heat insulation cylinder 10 is provided outside the heater 30, and the upper heat insulation cylinder 10 blocks the heat radiation channel of the heater 30 to the outside of the upper heat insulation cylinder 10, which is beneficial to reducing the heat loss of the heater 30 and thus beneficial to the heat conduction to the crucible through the crucible support 51. At the same time, in the present application, a lower heat insulation cylinder 20 is provided below the heater 30, that is, the lower part of the crucible support 51 is arranged inside the lower heat insulation cylinder 20, and the inner diameter of the lower heat insulation cylinder 20 is smaller than the inner diameter of the upper heat insulation cylinder 10. In this way, the heat radiation channel of the heater 30 along the first direction D1 to the lower part of the crucible support 51 is reduced, which is beneficial to reducing the temperature inside the lower heat insulation cylinder 20, and thus beneficial to reducing the temperature of the lower part of the crucible support 51, reducing the oxygen in the crucible from entering the silicon melt, and further beneficial to reducing the oxygen content of the single crystal silicon bar.

[0057] Please refer to Figure 1, in an alternative embodiment of the present application, the heater foot plate 40 further includes a connecting bridge 42, a support leg 43, and a base 44; the connecting bridge 42 is vertically connected to the connecting portion 41, and along the first direction D1, the connecting bridge 42 is located on the side of the connecting portion 41 closer to the lower heat insulation cylinder 20. Along the second direction (not shown in the figure, the second direction is perpendicular to the plane where the support leg 43 is located), the connecting bridge 42 is located on the side of the connecting portion 41 away from the heater 30. The second direction is the thickness direction of the support leg 43, and the second direction is parallel to the horizontal plane; the support leg 43 is vertically connected to the connecting bridge 42. Along the first direction D1, the support leg 43 is located on the side of the connecting bridge 42 away from the connecting portion 41. Along the second direction, the support leg 43 is located on the side of the connecting bridge 42 away from the connecting portion 41; the base 44 is vertically connected to the support leg 43. Along the first direction D1, the base 44 is located on the side of the support leg 43 away from the connecting bridge 42; along the second direction, the base 44 is located on the side of the support leg 43 closer to the connecting portion 41.

[0058] Specifically, in this embodiment, the heater foot plate 40 includes a connecting portion 41, a connecting bridge 42, a support leg 43, and a base 44. The connecting portion 41 is connected to the heater 30, the connecting bridge 42 is connected to the connecting portion 41 and the support leg 43, and the support leg 43 is also connected to the base 44. The connecting portion 41 and the connecting bridge 42 are perpendicular, the support leg 43 is perpendicular to the connecting bridge 42, and the base 44 is perpendicular to the support leg 43. Along the first direction D1, the connecting portion 41, the connecting bridge 42, the support leg 43, and the base 44 are connected in sequence to form an arcuate-like structure as shown in the figure, and the convexity faces the side of the heater foot plate 40 away from the lower heat insulation cylinder 20. The setting of the heater foot plate 40 in the present application increases the distance between the heater foot plate 40 and the crucible rim 51, which is beneficial to reducing the radiative heat dissipation of the heater foot plate 40 to the crucible rim 51, and at the same time also reserves sufficient space for the installation of the lower heat insulation cylinder 20.

[0059] It should be noted that the outer wall of the heater 30 includes a groove adapted to the connecting portion 41 of the heater foot plate 40. Optionally, the connecting portion 41 of the heater 30 and the heater foot plate 40 are connected by bolts or electroplating. The present application does not specifically limit the size of the heater foot plate 40, and it can be designed according to actual needs. For example, the size of the heater foot plate 40 can be set according to the required resistance value.

[0060] It should also be noted that the material of the heater foot plate 40 can be isostatic graphite, carbon-carbon composite material, or a composite material composed of isostatic graphite and carbon-carbon composite material. An alternative embodiment provided by the present application is that the material of the heater foot plate 40 is isostatic graphite; another alternative embodiment provided by the present application is that the material of the heater foot plate 40 is carbon-carbon composite material; yet another alternative embodiment provided by the present application is that the material of the heater foot plate 40 is a composite material formed by isostatic graphite and carbon-carbon composite material.

[0061] Please refer to Figure 2 Figure 2 , in an alternative embodiment of the present application, the thermal field structure 100 in the single crystal furnace further includes an electrode 70, the electrode 70 is correspondingly arranged with the heater foot plate 40, the electrode 70 is located on the side of the base 44 of the heater foot plate 40 away from the connection bridge 42, and the electrode 70 is connected to the base 44 through an electrode bolt 71.

[0062] Specifically, in this embodiment, the thermal field structure 100 further includes an electrode 70 correspondingly arranged with the heater foot plate 40, the electrode 70 is connected to the base 44 of the heater foot plate 40 and fixed through an electrode bolt 71. The heater 30 is electrically connected to the heater foot plate 40, the heater foot plate 40 is electrically connected to the electrode 70, and a thermal circuit is formed through the electrode 70 and a power source outside the thermal field structure 100, so that the heater 30 generates heat.

[0063] Please refer to Figure 1 Figure 1 , in an alternative embodiment of the present application, the inner diameter of the lower heat insulation cylinder 20 is smaller than the inner diameter of the heater 30.

[0064] Specifically, in the single crystal furnace provided in the present application, the inner diameter of the lower heat insulation cylinder 20 of the thermal field structure 100 is smaller than the inner diameter of the upper heat insulation cylinder 10, reducing the channel for the heat of the heater 30 to radiate to the lower part of the crucible flange 51 along the first direction D1, which is beneficial to reducing the temperature in the lower heat insulation cylinder 20, thus beneficial to reducing the temperature of the lower part of the crucible flange 51, and further beneficial to reducing the oxygen content in the single crystal rod. In this embodiment, the inner diameter of the lower heat insulation cylinder 20 is further set to be smaller than the inner diameter of the heater 30, which is further beneficial to reducing the channel for the heat of the heater 30 to radiate to the lower part of the crucible flange 51 along the first direction D1, thereby further beneficial to reducing the temperature in the lower heat insulation cylinder 20 and further beneficial to reducing the oxygen content in the single crystal rod.

[0065] It should be noted that only the relative positional relationship of the upper heat insulation cylinder 10, the lower heat insulation cylinder 20 and the heater 30 is schematically shown in the drawings of the present application, and it does not represent their actual relative sizes. For example, the inner diameter of the lower heat insulation cylinder 20 being smaller than the inner diameter of the heater 30 is not clearly shown in the drawings. The drawings are for reference only and not limited thereto.

[0066] Please refer to Figure 1 Figure 1 , in an alternative embodiment of the present application, it further includes a first outward turning flange 61. The first outward turning flange 61 is located on the side of the lower heat insulation cylinder 20 close to the upper heat insulation cylinder 10, and the first outward turning flange 61 connects the lower heat insulation cylinder 20 and the upper heat insulation cylinder 10.

[0067] Specifically, in the single crystal furnace provided by the present application, the thermal field structure 100 includes an upper heat insulation cylinder 10 and a lower heat insulation cylinder 20. The upper heat insulation cylinder 10 is located above the lower heat insulation cylinder 20, and the heater 30 is located in the first heat insulation space 101 inside the upper heat insulation cylinder 10. The setting of the upper heat insulation cylinder 10 is conducive to reducing the heat radiation of the heater 30 to the outside of the upper heat insulation cylinder 10, reducing heat loss, and thus improving the single output of the single crystal rod. The setting of the lower heat insulation cylinder 20, due to the reduction of its inner diameter relative to that of the upper heat insulation cylinder 10, is conducive to reducing the heat radiation of the heater 30 to the lower heat insulation cylinder 20, thereby reducing the temperature of the lower heat insulation cylinder 20 and further reducing the oxygen content in the single crystal rod. In this embodiment, the thermal field structure 100 further includes a first outward turning flange 61. The first outward turning flange 61 is located at the top of the lower heat insulation cylinder 20 and cooperates with the upper heat insulation cylinder 10 to form a relatively complete closed interval. On the one hand, it is conducive to preventing heat from leaking through the gap between the upper heat insulation cylinder 10 and the lower heat insulation cylinder 20, enabling more heat to play a role inside the upper heat insulation cylinder 10. On the other hand, when argon gas passes through this interval, the cooling effect on the space inside the lower heat insulation cylinder 20 is more obvious, thereby further reducing the temperature inside the lower heat insulation cylinder 20 and further reducing the oxygen content in the single crystal rod.

[0068] Please continue to refer to Figure 1 , in an alternative embodiment of the present application, it further includes a second outward turning flange 62. The second outward turning flange 62 is located on the side of the upper heat insulation cylinder 10 away from the lower heat insulation cylinder 20.

[0069] Specifically, in the single crystal furnace provided by the present application, the thermal field structure 100 includes an upper heat insulation cylinder 10, and the heater 30 is located in the first heat insulation space 101 inside the upper heat insulation cylinder 10, which is conducive to reducing the heat loss of the heater 30 and improving the heat preservation effect, thereby improving the single output of the single crystal rod. In this embodiment, the thermal field structure 100 further includes a second outward turning flange 62. The second outward turning flange 62 is located on the side of the upper heat insulation cylinder 10 away from the lower heat insulation cylinder 20. The setting of the second outward turning flange 62 in the present application facilitates the connection between the upper heat insulation cylinder 10 and other structures in the thermal field structure 100, and also helps to reduce the heat loss of the heater 30, and further improves the single output of the single crystal rod.

[0070] Please refer to Figure 2 , in an alternative embodiment of the present application, it further includes a heat preservation barrel 80. The heat preservation barrel 80 is located outside the upper heat insulation cylinder 10 and the lower heat insulation cylinder 20, and the second outward turning flange 62 is in contact with the inner wall of the heat preservation barrel 80.

[0071] Specifically, the upper heat insulation cylinder 10 in the present application is conducive to reducing the heat radiation of the heater 30 upward outside the upper heat insulation cylinder 10, which is conducive to reducing heat loss, and thus is conducive to improving the single output of the single crystal rod; the lower heat insulation cylinder 20 in the present application is conducive to reducing the channel for the heat of the heater 30 to radiate downward into the lower heat insulation cylinder 20, which is conducive to reducing the temperature inside the lower heat insulation cylinder 20, and thus is conducive to reducing the oxygen content of the single crystal rod; through the improvement of the internal heat field structure 100 of the single crystal furnace in the present application, heat is guided to achieve the reduction of the oxygen content in the single crystal rod while improving the single output of the single crystal rod. In this embodiment, the single crystal furnace further includes a heat preservation barrel 80. The heat preservation barrel 80 is arranged on the periphery of the upper heat insulation cylinder 10 and the lower heat insulation cylinder 20, which is conducive to improving the heat preservation effect. The second outward-turning flange 62 is in contact with the inner wall of the heat preservation barrel 80, which is further conducive to reducing the heat radiation between the upper heat insulation cylinder 10 and the space between the heat preservation barrel 80, and thus is conducive to improving the heating efficiency and the single output of the single crystal rod.

[0072] Please refer to Figure 1 and Figure 2 , in an alternative embodiment of the present application, it further includes a crucible support rod 53, and the crucible support rod 53 is located on the side of the crucible support 52 away from the crucible rim 51.

[0073] Specifically, the internal heat field structure 100 of the single crystal furnace provided in the present application includes an upper heat insulation cylinder 10, a lower heat insulation cylinder 20, a heater 30, a heater foot plate 40, and a crucible rim 51 and a crucible support 52. Along the first direction D1, the lower heat insulation cylinder 20 is located below the upper heat insulation cylinder 10, the heater 30 is located in the first heat insulation space 101 of the upper heat insulation cylinder 10, at least part of the crucible rim 51 is located in the first heat insulation space 101 of the upper heat insulation cylinder 10, at least part of the crucible rim 51 is located in the second heat insulation space 202 of the lower heat insulation cylinder 20. The setting of the upper heat insulation cylinder 10 is conducive to reducing the heat loss of the heater 30, and further conducive to the heat conduction of the heater 30 to the crucible rim 51 in the first heat insulation space 101, and at the same time is conducive to improving the heat preservation effect. The inner diameter of the lower heat insulation cylinder 20 is smaller than the inner diameter of the upper heat insulation cylinder 10, which is conducive to reducing the heat radiation from the upper heat insulation cylinder 10 into the lower heat insulation cylinder 20, and is conducive to reducing the temperature of the corresponding crucible rim 51 in the lower heat insulation cylinder 20, and thus is conducive to reducing the oxygen content of the single crystal rod. The internal heat field structure 100 of the single crystal furnace provided in the present application further includes a crucible support 52, and the crucible support 52 is located below the crucible rim 51. The heat of the heater 30 is transferred to the inside of the crucible rim 51 through the crucible rim 51; further, a crucible support rod 53 is provided in this embodiment. The crucible support rod 53 is located on the side of the crucible support 52 away from the crucible rim 51. The crucible support rod 53 forms a certain support for the crucible support 52. Optionally, the crucible support rod 53 can be lifted and lowered to drive the crucible support 52 and the crucible rim 51 to be lifted and lowered together, which is conducive to adjusting the heights of the crucible rim 51 and the crucible support 52.

[0074] Please continue to refer to Figure 1 andFigure 2 , An optional implementation provided by the present application is that it further includes a crucible, and the crucible is located in the accommodation space 05 formed by the crucible ring 51 and the crucible support 52.

[0075] Specifically, in this implementation, the single crystal furnace further includes a crucible (not shown in the figure), the crucible is used to hold silicon material, the single crystal furnace further includes a crucible ring 51 and a crucible support 52, the crucible support 52 is located below the crucible ring 51, the crucible is located in the accommodation space 05 formed by the crucible ring 51 and the crucible support 52, and the heat of the heater 30 is transferred to the crucible through the crucible ring 51, so that the silicon material in the crucible is melted.

[0076] It can be understood that the single crystal furnace provided by the present application includes a thermal field structure 100. In the thermal field structure 100, the setting of the upper heat insulation cylinder 10 blocks the heat radiation dissipation channel of the heater 30 to the outside of the upper heat insulation cylinder 10, which is beneficial to improving the heat preservation effect, reducing heat loss, and thus beneficial to improving the single output of the single crystal rod. At the same time, the setting of the lower heat insulation cylinder 20 blocks the heat radiation channel of the heater 30 downward, which is beneficial to reducing the temperature in the lower heat insulation cylinder 20, and thus beneficial to reducing the oxygen content in the single crystal rod.

[0077] In summary, a single crystal furnace provided by the present utility model at least achieves the following beneficial effects:

[0078] The present application provides a single crystal furnace, including a thermal field structure, the thermal field structure includes an upper heat insulation cylinder, a lower heat insulation cylinder, a heater and at least two heater feet; wherein, the lower heat insulation cylinder is located below the upper heat insulation cylinder, the heater is located inside the upper heat insulation cylinder, both the upper heat insulation cylinder and the lower heat insulation cylinder are cylindrical, the inner diameter of the lower heat insulation cylinder is smaller than the inner diameter of the upper heat insulation cylinder, the upper heat insulation cylinder includes a first avoidance opening, the lower heat insulation cylinder includes a second avoidance opening, the heater feet pass through the first avoidance opening and the second avoidance opening, and the settings of the first avoidance opening and the second avoidance opening facilitate the passage of the heater feet; the setting of the upper heat insulation cylinder blocks the heat radiation dissipation channel of the heater to the outside of the upper heat insulation cylinder, which is beneficial to improving the heat preservation effect, reducing heat loss, and thus beneficial to improving the single output of the single crystal rod. At the same time, the setting of the lower heat insulation cylinder is beneficial to blocking the heat radiation channel of the heater downward, which is beneficial to reducing the temperature in the lower heat insulation cylinder, and thus beneficial to reducing the oxygen content in the single crystal rod.

[0079] Although some specific embodiments of the present utility model have been described in detail by way of examples, those skilled in the art should understand that the above examples are only for illustration and not for limiting the scope of the present utility model. Those skilled in the art should understand that the above embodiments can be modified without departing from the scope and spirit of the present utility model. The scope of the present utility model is defined by the appended claims.

Claims

1. A single crystal furnace, characterized in that: It includes a thermal field structure, which includes an upper thermal insulation tube, a lower thermal insulation tube, a heater and at least two heater foot plates; Along a first direction, the lower insulation tube is located below the upper insulation tube, and the first direction is a height direction of the thermal field structure; The heater is located inside the upper insulation tube, and the heater is connected to the connection portion of the heater foot plate; the upper insulation tube is located on the side of the connection portion away from the heater, and the lower insulation tube is located inside the heater foot plate; The upper insulation tube and the lower insulation tube are both cylindrical, and the inner diameter of the lower insulation tube is smaller than the inner diameter of the upper insulation tube; The upper heat-insulating tube includes a first avoidance opening, the lower heat-insulating tube includes a second avoidance opening, and the heater foot plate passes through the first avoidance opening and the second avoidance opening.

2. The single crystal furnace according to claim 1, characterized in that: The heater foot plate also includes a connecting bridge, supporting legs and a base; The connecting bridge is vertically connected to the connecting portion. Along the first direction, the connecting bridge is located at a side of the connecting portion close to the lower heat insulation cylinder. Along the second direction, the connecting bridge is located at a side of the connecting portion away from the heater. The second direction is the thickness direction of the supporting leg. The supporting leg is vertically connected to the connecting bridge. Along the first direction, the supporting leg is located at a side of the connecting bridge away from the connecting portion. Along the second direction, the supporting leg is located at a side of the connecting bridge away from the connecting portion. The base is vertically connected to the supporting leg. Along the first direction, the base is located on a side of the supporting leg away from the connecting bridge; along the second direction, the base is located on a side of the supporting leg close to the connecting portion.

3. The single crystal furnace according to claim 2, characterized in that: It also includes an electrode, which is arranged corresponding to the heater foot plate, and is located on a side of the base of the heater foot plate away from the connecting bridge, and the electrode is connected to the base through an electrode bolt.

4. The single crystal furnace according to claim 1, characterized in that: The inner diameter of the lower heat-insulating cylinder is smaller than the inner diameter of the heater.

5. The single crystal furnace according to claim 1, characterized in that: It also includes a first outward-turned flange, which is located on a side of the lower insulation tube close to the upper insulation tube, and the first outward-turned flange connects the lower insulation tube and the upper insulation tube.

6. The single crystal furnace according to claim 1, characterized in that: It also includes a second outward-turned flange, which is located on a side of the upper insulation tube away from the lower insulation tube.

7. The single crystal furnace according to claim 6, characterized in that: It also includes a heat-insulating barrel, which is located outside the upper heat-insulating barrel and the lower heat-insulating barrel, and the second outward-turned flange is in contact with the inner wall of the heat-insulating barrel.

8. The single crystal furnace according to claim 1, characterized in that: It also includes a crucible and a crucible support. Along the first direction, the crucible support is located below the crucible, and the crucible is located on the inner side of the heater and the lower insulation cylinder.

9. The single crystal furnace according to claim 8, characterized in that: It also includes a crucible support rod, which is located at a side of the crucible support away from the crucible.

10. The single crystal furnace according to claim 9, characterized in that: Also included is a crucible, which is located in a containing space formed by the crucible and the crucible holder.

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