Single crystal furnace

Abstract

The utility model discloses a single crystal furnace, which comprises: a furnace body, in which a heating chamber with an open top is arranged; the furnace cover can cover the furnace body; a concave cavity with a top opening is formed in the inner side of the furnace cover; the liquid-cooled heat shield is embedded in the top opening; the liquid cooling heat shield is provided with a containing cavity with two through ends, the containing cavity is provided with an upper cavity opening and a lower cavity opening, the upper cavity opening is communicated with the concave cavity and is opposite to the top opening, and the lower cavity opening is communicated with the heating cavity, so that a crystal bar growth channel is formed between the upper cavity opening and the top opening; the heat insulation part is arranged in the concave cavity and is arranged outside the crystal bar growth channel in a sleeving manner, so that a heat insulation space is formed between the heat insulation part and the furnace cover while the crystal bar growth channel and the furnace cover are separated; the surface of the heat insulation piece opposite to the crystal bar growth channel is a reflecting surface. According to the single crystal furnace, the equal-diameter power consumption can be reduced, and the production cost of crystal pulling is remarkably reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to single crystal furnace technical field, concretely relates to a single crystal furnace. BACKGROUND

[0002] At present, the temperature in the furnace during the crystal production of single crystal furnace is mainly provided through the main heater surrounding the crucible and the auxiliary heater located at the bottom of the crucible. The temperature control in the equal-diameter stage is realized by the heating of the main heater. In the crystal pulling stage, the main energy loss of the single crystal furnace comes from the cooling of the water-cooled heat shield, the exhaust of the vacuum pipeline and other furnace body cooling structures. According to the calculation and industry experience, the heater power in the equal-diameter stage needs to reach more than 55kW to ensure stable crystal pulling. This requirement leads to the problems of high power consumption, high crystal pulling cost, short service life of the heater and low heat effective utilization rate when the crystal bar manufacturers produce the crystal bar.

[0003] In view of how to improve the heat preservation effect and increase the effective utilization rate of the heater heat, the technical personnel in the field urgently need to develop a single crystal furnace capable of reducing the equal-diameter power consumption to significantly reduce the production cost of crystal pulling. SUMMARY

[0004] The utility model aims at solving one of the technical problems in the related art to some extent. Therefore, the utility model provides a single crystal furnace which can reduce the equal-diameter power consumption and significantly reduce the production cost of crystal pulling.

[0005] In order to achieve the above purpose, the utility model adopts the following technical scheme in the first aspect:

[0006] A single crystal furnace, comprising: a furnace body, a heating cavity with an open top being arranged in the furnace body; a furnace cover, the furnace cover being coverable on the furnace body; a concave cavity with a top opening being arranged on the inner side of the furnace cover; a liquid-cooled heat shield, the liquid-cooled heat shield being embedded in the open top; the liquid-cooled heat shield having a containing cavity penetrating through both ends, the containing cavity having an upper cavity opening and a lower cavity opening, the upper cavity opening being communicated with the concave cavity and opposite to the top opening, and the lower cavity opening being communicated with the heating cavity to form a crystal bar growth channel between the upper cavity opening and the top opening; and a heat insulation member, the heat insulation member being arranged in the concave cavity and sleeved outside the crystal bar growth channel to form a heat insulation space between the heat insulation member and the furnace cover while separating the crystal bar growth channel and the furnace cover; the surface of the heat insulation member opposite to the crystal bar growth channel being a reflecting surface to reduce the heat radiation from the crystal bar growth channel to the heat insulation space.

[0007] Optionally, the heat insulation member has a through space with a top opening and a bottom opening; the crystal bar growth channel is located in the center of the through space and passes through the top opening and the bottom opening respectively; in the direction in which the crystal bar growth channel extends towards the top opening, the distance from the inner wall of the through space to the center of the crystal bar growth channel decreases.

[0008] Optionally, the heat insulation member comprises a ring-shaped main body and a first cylinder; one end of the first cylinder penetrates the surface of the ring-shaped main body and is connected with the ring-shaped main body, so that the other end of the first cylinder forms the top opening and is in gap cooperation with the top opening.

[0009] Optionally, the first cylinder is provided with a avoiding opening for avoiding the gas outlet arranged in the top opening.

[0010] Optionally, the heat insulation member further comprises a second cylinder surrounding the periphery of the ring-shaped main body and connected with one end of the ring-shaped main body; the inside of the second cylinder forms the through space, and the other end of the second cylinder forms the bottom opening.

[0011] Optionally, a plurality of functional openings penetrating the heat insulation member are formed in the ring-shaped main body, so that parts or lines of sight pass through the heat insulation member through the functional openings.

[0012] Optionally, the inner wall of the through space has a reflective layer forming the reflective surface.

[0013] Optionally, the heat insulation member is made of a heat-reflecting material, and the inner wall of the through space is provided as a smooth surface to form the reflective surface.

[0014] Optionally, the inner side of the furnace cover is provided with a connecting piece; the heat insulation member is fixedly connected with the inner wall of the recess through the connecting piece.

[0015] When the furnace cover is closed on the furnace opening, the bottom opening is attached to the top of the liquid-cooled heat shield or to the top end surface of the furnace body.

[0016] Optionally, the furnace body is internally provided with a heat preservation structure; the heat preservation structure comprises a heat preservation cylinder and a reflective cylinder sleeved outside the heat preservation cylinder; the center of the heat preservation cylinder forms the heating cavity.

[0017] Optionally, the liquid-cooled heat shield comprises a heat shield main body; the heat shield main body is made of stainless steel; the outer side of the heat shield main body is a polished surface, and the roughness Ra of the polished surface is less than or equal to 0.8.

[0018] The above-mentioned scheme has at least one of the following beneficial effects:

[0019] In one aspect, the heat shield reflects the heat radiated from the crystal bar in the crystal bar growth channel to the furnace cover and the heat radiation overflowing from the liquid-cooled heat shield through the cavity by the inner side reflective surface of the heat shield, significantly reducing the heat taken away by the internal cooling system of the furnace cover. At the same time, the heat insulation space formed between the outer surface of the heat shield and the furnace cover delays the air heat convection and heat exchange, slows down the temperature rising speed of the furnace cover, and further reduces the heat load of the cooling system.

[0020] In another aspect, by reducing heat loss and delaying temperature rise, the heat shield enables the heat source (heater) arranged in the heating cavity to maintain the temperature requirement of the single crystal furnace in the constant diameter stage at a lower power consumption, significantly reducing energy consumption and production cost.

[0021] Secondly, the heat shield cooperates with the furnace body, furnace cover and liquid-cooled heat shield of the single crystal furnace, optimizes the heat distribution and reflection efficiency in the heat field, significantly improves the heat management performance of the single crystal furnace, and realizes efficient energy saving and stable crystal pulling.

[0022] The features and advantages of the present application will be described in detail in the following specific embodiments and drawings. The best embodiment or means of the present application will be described in detail in conjunction with the drawings, but it is not a limitation of the technical scheme of the present application. In addition, these features, elements and components appearing in each of the following text and drawings are multiple, and different symbols or numbers are marked for convenience of representation, but all represent the same or similar structure or function parts. BRIEF DESCRIPTION OF DRAWINGS

[0023] The present application will be further described below in conjunction with the drawings:

[0024] Figure 1 The structure of the single crystal furnace described in some embodiments is shown in the structure of the heat shield.

[0025] Figure 2 The exploded view of the single crystal furnace described in some embodiments is shown.

[0026] Figure 3 The structure of the heat shield described in some embodiments is shown.

[0027] Figure 4 The structure of the heat shield described in some embodiments is shown. Figure 1 The enlarged view of A in the drawing.

[0028] Figure 5 The enlarged view of B in the drawing. Figure 1 The enlarged view of B in the drawing.

[0029] In which:

[0030] 10, furnace body; 11, heating cavity; 111, top opening; 12, heat preservation structure; 121, heat preservation cylinder; 122, reflective cylinder;

[0031] 20. Furnace cover; 21. Top opening; 22. Cavity; 221. Gas outlet; 23. Connecting parts;

[0032] 30. Liquid-cooled heat shield; 31. Receptacle cavity; 311. Upper cavity opening; 312. Lower cavity opening; 32. Heat shield body; 321. Flow channel; 322. Polished surface; 33. Heat shield hard felt;

[0033] 40. Insulation component; 41. Accommodation space; 42. Top opening; 43. Bottom opening; 44. Annular body; 411. Functional opening; 45. First cylinder; 451. Clearance opening; 46. Second cylinder. Detailed Implementation

[0034] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described are intended to explain this utility model and should not be construed as limiting it.

[0035] In the description of this utility model, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0036] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0037] In the description of this utility model, unless otherwise stated, "a plurality of" means two or more, and "several" means one or more.

[0038] The terms "an embodiment," "example," or "trademark" used in this specification refer to a particular feature, structure, or characteristic described in connection with the embodiment itself that may be included in at least one embodiment disclosed in this utility model. The phrase "in an embodiment" appearing in various places throughout the specification does not necessarily refer to the same embodiment.

[0039] As shown in Figure 1 and Figure 2 The present embodiment provides a single crystal furnace, which comprises a furnace body 10, a furnace cover 20, a liquid-cooled heat shield 30, and a heat insulation member 40.

[0040] The furnace body 10 is provided with a heating cavity 11 with a top opening 111. The furnace cover 20 can be covered on the furnace body 10. The inner side of the furnace cover 20 is provided with a concave cavity 22 with a top opening 21. For example, the furnace cover 20 is covered on the furnace body 10 and covers the top opening 111 inside, the top opening 111 is located in the concave cavity 22 and the top opening 111 is opposite to the top opening 21.

[0041] The liquid-cooled heat shield 30 is embedded in the top opening 111. The liquid-cooled heat shield 30 has a containing cavity 31 with two ends through. The containing cavity 31 has an upper cavity opening 311 and a lower cavity opening 312. The upper cavity opening 311 leads to the concave cavity 22 and is opposite to the top opening 21, and the lower cavity opening 312 communicates with the heating cavity 11 to form a crystal bar growth channel between the upper cavity opening 311 and the top opening 21. For example, the crystal bar growth channel is a channel for the upward growth of a cylindrical crystal bar in the vertical direction.

[0042] The heat insulation member 40 is arranged in the concave cavity 22 and covers the crystal bar growth channel, so that the crystal bar growth channel is separated from the concave cavity 22, and a relatively closed heat insulation space is formed in the area between the heat insulation member 40 and the furnace cover 20. The surface of the heat insulation member 40 opposite to the crystal bar growth channel is a reflective surface, which is used to reduce the heat radiation from the crystal bar growth channel to the heat insulation space. For example, the heat insulation space extends upward from the bottom of the furnace cover 20 to the top opening 21 and completely covers the inner side surface of the furnace cover 20 in 360 degrees.

[0043] The heat insulation member 40 of the present embodiment has a reflective surface on its inner surface, which can reflect the heat radiation that the crystal bar originally radiates to the furnace cover 20 and the heat radiation that originally overflows from the upper cavity opening 311 and radiates to the furnace cover 20 back, thereby reducing the heat taken away by the cooling system in the furnace cover 20. On the other hand, since the heat insulation member 40 covers a large range and covers the crystal bar growth channel completely, a relatively closed heat insulation space can be formed between its outer surface and the furnace cover 20. The air in the space flows slowly, which can slow down the air heat convection and heat exchange to some extent, thereby slowing down the temperature rising speed of the furnace cover 20 and reducing the heat taken away by the cooling system of the furnace cover 20 in unit time to some extent. Therefore, the single crystal furnace 10 provided by the present embodiment can enable the heater to maintain the temperature requirement of the heat field at a relatively low power consumption in the equal-diameter stage, which has a significant energy-saving effect and can significantly reduce the production cost of crystal pulling.

[0044] In some embodiments, as shown in Figure 1 andFigure 2 As shown, the heat insulation member 40 has a through space 41 with two ends, and the through space 41 has a top opening 42 and a bottom opening 43. The crystal bar growth channel is located in the center of the through space 41 and passes through the top opening 42 and the bottom opening 43, respectively. In the example, the through space 41 is through at the upper and lower ends, the top opening 42 extends into the top opening 21, and the bottom opening 43 is sleeved outside the upper cavity opening 311 and abuts against the top end face of the furnace body 10. In the direction in which the crystal bar growth channel extends towards the top opening 21, the distance from the inner wall of the through space 41 to the center of the crystal bar growth channel decreases.

[0045] In the example, the heat insulation member 40 is a thin-walled structure and has a shape of an inverted funnel as a whole, so as to adapt to the shape of the furnace cover 20 and form a gap with the furnace cover 20, and the size of the gap is at least 10 mm. By setting the gap with sufficient size, it is ensured that the heat insulation effect of the heat insulation space can meet the expected requirements.

[0046] Since the crystal bar is grown upward from the crucible located in the heating cavity 11 during production, the temperature of the area of the crystal bar closer to the heating cavity 11 is higher. By setting the distance from the inner wall of the through space 41 to the center of the crystal bar growth channel to decrease in the direction in which the crystal bar growth channel extends towards the top opening 21, the temperature of the crystal bar surface is positively correlated with the distance from the heat insulation member 40. The higher the temperature of the crystal bar surface is, the farther the distance from the heat insulation member 40 is, and the heat of the crystal bar is controlled by the distance to reach the heat insulation member 40.

[0047] In the example, in order to improve the heat insulation capacity of the heat insulation member 40, the heat insulation member 40 can also have a hollow structure, and by setting a hollow interlayer inside, the rate of heat conduction can also be reduced to a certain extent.

[0048] In some embodiments, as shown in Figures 1-3 The heat insulation member 40 includes a ring-shaped body 44 and a first cylinder 45. One end of the first cylinder 45 penetrates the surface of the ring-shaped body 44 and is connected with the ring-shaped body 44, so that the other end of the first cylinder 45 forms the top opening 42 and is matched with the top opening 21. In this way, when the heat insulation member 40 is assembled, the top opening 42, i.e., the end of the first cylinder 45, can be inserted into the top opening 21 of the furnace cover 20, and the outer wall of the top opening 42 and the inner wall of the top opening 21 form a fit, which can realize horizontal positioning, ensure that the heat insulation member 40 is concentrically arranged with the top opening 21, and avoid that the heat insulation member 40 touches the crystal bar due to horizontal movement.

[0049] In some embodiments, as shown in Figures 1-3 The first cylinder 45 is provided with a clearance 451 for avoiding the gas outlet 221 arranged in the top opening 21. Corresponding to the number and position of the gas outlet 221 in the top opening 21 of the furnace cover 20, see Figure 4The avoidance openings 451 are correspondingly provided in plurality, and the plurality of avoidance openings 451 are uniformly distributed along the circumference of the barrel opening. For example, the avoidance openings 451 are provided as notches on the top opening 42. The notches are extended downward from the top opening 42 along the barrel wall by a certain distance, thereby reserving adjustment space for the top opening 42 in its axial direction, ensuring that the gas outlet 221 of the furnace cover 20 can fall into the corresponding notch without being blocked.

[0050] In some embodiments, the heat shield 40 further comprises a second barrel 46 surrounding and connected to the periphery of the annular body 44 at one end, the interior of the second barrel 46 forms the accommodation space 41, and the other end of the second barrel 46 forms the bottom opening 43. The second barrel 46 has a certain diameter and height, so that it can form enough space at the bottom opening 43 to accommodate the top opening 111 and the liquid-cooled heat shield 30 therein, while the liquid-cooled heat shield 30 reserves a certain lifting space.

[0051] In some embodiments, as shown in Figure 3 The annular body 44 is provided with a plurality of functional openings 411 penetrating the heat shield 40, so that parts or lines of sight can pass through the heat shield 40 through the functional openings 411.

[0052] For example, the plurality of functional openings 411 include two first through holes for the liquid supply pipeline of the liquid-cooled heat shield 30 to pass through, and the two first through holes are respectively arranged on the two sides of the top cover opening in the axial direction. The functional openings 411 further include a second through hole for cooperating with the viewing window on the furnace cover 20 to observe the inside of the furnace.

[0053] In addition, the heat shield 40 can be arranged on one of the furnace cover 20, the furnace body 10 or the liquid-cooled heat shield 30. For example, to fix the connecting piece 23 with the furnace cover 20, the functional openings 411 further include a third through hole for the connecting piece 23 to pass through.

[0054] In some embodiments, the inner wall of the accommodation space 41 has a reflective layer forming a reflecting surface. The reflective layer can be a molybdenum element plating layer.

[0055] In some embodiments, the heat shield 40 can also be made of a heat-reflecting material, and the inner wall of the accommodation space 41 is provided as a smooth surface to form a reflecting surface. The heat shield 40 is made of metal molybdenum. Molybdenum has excellent high-temperature resistance and can work stably in a furnace above ℃.

[0056] In some embodiments, as shown in Figure 1 The inside of the furnace cover 20 is provided with a connecting piece 23. The heat shield 40 is fixedly connected with the inner wall of the recessed cavity 22 through the connecting piece 23. For example, the connecting piece 23 is a threaded connecting piece 23.

[0057] When the furnace cover 20 is closed on the furnace body 10, the bottom opening 43 is attached to the top of the liquid-cooled heat shield 30 or to the top end face of the furnace body 10.

[0058] In some embodiments, as shown in Figure 2 The inner wall of the furnace body 10 is provided with a heat preservation structure 12. The heat preservation structure 12 includes a heat preservation cylinder 121 and a reflection cylinder 122 sleeved outside the heat preservation cylinder 121. The center of the heat preservation cylinder 121 forms a heating cavity 11. The heat preservation cylinder 121 is made of heat preservation felt or carbon-carbon material, and the reflection cylinder 122 is preferably a stainless steel cylinder. The inner side of the stainless steel cylinder is a polished surface with a roughness Ra less than or equal to 0.8, which can effectively reflect the heat conducted from the inside to the outside back to the inside of the heat field. The stainless steel cylinder can also be other reflective materials other than stainless steel.

[0059] For example, the liquid-cooled heat shield 30 is embedded in the heat preservation structure 12, and the top end face of the liquid-cooled heat shield 30 is almost flush with the end face of the heat preservation structure 12, thereby forming the top end face of the furnace body 10 together. The diameter of the second cylinder body 46 is greater than or equal to the inner diameter of the upper cavity opening 311, and the two are concentrically arranged, so that the bottom opening 43 falls on the top end face of the furnace body 10. Specifically, the bottom opening 43 can fall on the top end face of the liquid-cooled heat shield 30 or on the end face of the heat preservation structure 12, which is not limited here.

[0060] In some embodiments, as shown in Figure 1 and 5 The liquid-cooled heat shield 30 includes a heat shield body 32 with a flow channel 321 inside and a cylindrical heat shield hard felt 33. The overall shape of the heat shield body 32 is also cylindrical, and the heat shield hard felt 33 is arranged above and connected to the heat shield body 32. The centers of the two form a containing cavity 31, the upper cylinder opening of the heat shield hard felt 33 forms the upper cavity opening 311 of the containing cavity 31, and the lower cylinder opening of the heat shield body 32 forms the lower cavity opening 312 of the containing cavity 31.

[0061] The most effective section of the liquid-cooled heat shield 30 for cooling the crystal bar is the vertical section of the inner wall of the heat shield body 32, which is located at the bottom of the liquid-cooled heat shield 30 and is closest to the crystal bar. Therefore, in this embodiment, the liquid-cooled heat shield 30 adopts a segmented design, the most effective heat shield body 32 is arranged at the bottom, and the upper part is the heat shield hard felt 33. Only the flow channel 321 is arranged in the heat shield body 32, which reduces the height of the cooling section of the heat shield and effectively reduces heat loss without affecting the crystal pulling.

[0062] In some embodiments, the heat shield body 32 is a stainless steel article. The heat shield body 32 is welded by inner and outer layers of stainless steel plates, and a flow channel 321 is formed in the interlayer by welding a partition plate. The outer side of the heat shield body 32 is a polished surface 322. Specifically, the surface of the inner layer of stainless steel plates facing the shaft center is treated by blackening process to improve the heat absorption capacity, and the outer surface of the outer layer of stainless steel plates is treated by polishing process to be the polished surface 322, so as to be able to reflect.

[0063] The heat shield body 32 is the cooling device closest to the heat source in the heat field, and the power consumption taken away by the heat shield body 32 is the most in the water cooling process of crystal pulling, so that the reflection of the heat taken away by the heat shield body 32 can most efficiently reduce the power consumption. The existing heat shield is blackened as a whole, which is convenient for the heat shield body 32 to absorb heat and form a temperature gradient to achieve the effect of forming a crystal bar. In the embodiment, the blackening process of the outer side of the heat shield body 32 is cancelled, and the original blackening process is replaced by polishing of the original color of the stainless steel. The heat absorbed by the outer wall is changed to most of the heat reflected by the outer wall, while the blackening of the inner part is still retained, and the crystal forming effect is not affected.

[0064] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto. Those skilled in the art should understand that the present application includes but is not limited to the contents described in the above specific embodiments and the drawings. Any modification of the function and structure principle without deviating from the present application will be included in the scope of the claims.

Claims

1. A single crystal furnace characterized by comprising: The utility model relates to a crystal bar growth furnace, which comprises: a furnace body (10) provided with a heating cavity (11) with a top opening (111) inside; a furnace cover (20) capable of covering the furnace body (10); the inner side of the furnace cover (20) is provided with a concave cavity (22) with a top opening (21); a liquid-cooled heat shield (30) embedded in the top opening (111); the liquid-cooled heat shield (30) has a containing cavity (31) penetrating through both ends, the containing cavity (31) has an upper cavity opening (311) and a lower cavity opening (312), the upper cavity opening (311) leads to the concave cavity (22) and is opposite to the top opening (21), and the lower cavity opening (312) communicates with the heating cavity (11) to form a crystal bar growth channel between the upper cavity opening (311) and the top opening (21); and a heat insulation member (40) arranged in the concave cavity (22) and sleeved outside the crystal bar growth channel, so that the crystal bar growth channel is separated from the concave cavity while forming a relatively closed heat insulation space in the region between the heat insulation member (40) and the furnace cover (20); the surface of the heat insulation member (40) relative to the crystal bar growth channel is a reflective surface, so as to reduce the heat radiation from the crystal bar growth channel to the heat insulation space.

2. The single crystal furnace of claim 1, wherein The heat insulation member (40) has a containing space (41) penetrating through both ends, the containing space (41) has a top opening (42) and a bottom opening (43); the crystal bar growth channel is located in the center of the containing space (41) and penetrates through the top opening (42) and the bottom opening (43) respectively; in the direction in which the crystal bar growth channel extends towards the top opening (21), the distance from the inner wall of the containing space (41) to the center of the crystal bar growth channel decreases.

3. The single crystal furnace of claim 2, wherein The heat insulation member (40) comprises a ring-shaped main body (44) and a first cylinder (45); one end of the first cylinder (45) penetrates through the surface of the ring-shaped main body (44) and is connected with the ring-shaped main body (44), so that the other end of the first cylinder (45) forms the top opening (42) and is in gap cooperation with the top opening (21).

4. The single crystal furnace of claim 3, wherein The first cylinder (45) is provided with a avoiding opening (451) for avoiding a gas outlet (221) arranged in the top opening (21).

5. The single crystal furnace of claim 3, wherein The heat insulation member (40) further comprises a second cylinder (46) surrounding the periphery of the ring-shaped main body (44) and connected with one end of the ring-shaped main body (44), the inside of the second cylinder (46) forms the containing space (41), and the other end of the second cylinder (46) forms the bottom opening (43).

6. The single crystal furnace of claim 3, wherein The ring-shaped main body (44) is provided with a plurality of functional openings (411) penetrating through the heat insulation member (40), so that parts or lines of sight can pass through the heat insulation member (40) through the functional openings (411).

7. The single crystal furnace of claim 2, wherein The inner wall of the containing space (41) has a reflective layer forming the reflective surface; or The heat insulation piece (40) is made of heat reflecting material, and the inner wall of the accommodating space (41) is provided with a smooth surface to form the reflecting surface.

8. The single crystal furnace of any one of claims 2-7, wherein, The furnace cover (20) is internally provided with a connecting piece (23); the heat insulation piece (40) is fixedly connected with the inner wall of the concave cavity (22) through the connecting piece (23). When the furnace cover (20) covers the furnace body, the bottom opening (43) is attached to the top of the liquid cooling heat shield (30) or the top end surface of the furnace body (10).

9. The single crystal furnace of any one of claims 1-7, wherein, The furnace body (10) is internally provided with a heat preservation structure (12); the heat preservation structure (12) comprises a heat preservation cylinder (121) and a reflecting cylinder (122) sleeved outside the heat preservation cylinder (121); the center of the heat preservation cylinder (121) forms the heating cavity (11).

10. The single crystal furnace of any one of claims 1-7, wherein, The liquid cooling heat shield (30) comprises a heat shield main body (32); the heat shield main body (32) is made of stainless steel; the outer side of the heat shield main body (32) is a polished surface (322), and the roughness Ra of the polished surface (322) is less than or equal to 0.8.

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