Water cooling screen and single crystal furnace

Abstract

The utility model discloses a water cooling screen which comprises a water cooling screen body, the water cooling screen body is of a barrel-shaped structure with two through ends, the water cooling screen body comprises an inner wall, an outer wall and a bottom wall, the inner wall, the outer wall and the bottom wall define a containing cavity, the thickness of the outer wall is larger than that of the inner wall, and an air heat preservation layer is arranged at the bottom of the water cooling screen body. According to the water-cooling screen disclosed by the utility model, thermal resistance can be increased and heat transfer from a thermal field to the water-cooling screen can be reduced by increasing the thickness of the outer wall, radiative heat transfer from a silicon melt to the water-cooling screen can be weakened by arranging the air thermal insulation layer, the cooling effect of the water-cooling screen on a silicon single crystal rod is ensured, and energy consumption of a heater for compensating lost heat is reduced; the oxygen content of the silicon single crystal rod is reduced, and the growth rate of the silicon single crystal rod can be increased. The utility model also discloses a single crystal furnace.

Description

Technical Field

[0001] This utility model relates to the field of monocrystalline silicon production technology, and more specifically, to a water-cooled screen and a monocrystalline furnace. Background Technology

[0002] In the Czochralski process for growing single-crystal silicon, the erosion of the crucible by the molten silicon is considered the main source of oxygen content in single-crystal silicon. As the crucible wall temperature increases, the erosion effect of the molten silicon on the crucible intensifies, leading to an increase in the oxygen content in the single-crystal silicon.

[0003] In the Czochralski process single-crystal silicon growth furnace, a water-cooled screen surrounds the single-crystal silicon rod. Cooling water is circulated within the screen as a heat transfer medium, primarily carrying away the latent heat of crystallization from the silicon rod to increase its growth rate. Some heat from the molten silicon is transferred to the water-cooled screen via thermal radiation and carried out of the furnace by the cooling water. Due to heat loss from the molten silicon, the heater power needs to be increased to maintain the molten silicon temperature and stabilize crystal growth. On the one hand, increasing the heater power leads to an increase in the crucible wall temperature, ultimately increasing the oxygen content of the single-crystal silicon rod. On the other hand, due to interference from the thermal radiation of the molten silicon, the cooling effect of the water-cooled screen on the crystal rod is limited, thus limiting the improvement in the growth rate of the single-crystal silicon rod.

[0004] Therefore, how to reduce the oxygen content of monocrystalline silicon rods and increase their growth rate has become a technical problem that urgently needs to be solved by those skilled in the art. Utility Model Content

[0005] In view of this, the purpose of this utility model is to provide a water-cooled screen to reduce the oxygen content of monocrystalline silicon rods and increase the growth rate of monocrystalline silicon rods.

[0006] Another key aspect of this invention is the disclosure of a single-crystal furnace including the aforementioned water-cooled screen.

[0007] To achieve the above objectives, this utility model provides the following technical solution:

[0008] A water-cooled screen includes a water-cooled screen body, which is a cylindrical structure with two through ends. The water-cooled screen body includes an inner wall, an outer wall, and a bottom wall, which together form a receiving cavity. The thickness of the outer wall is greater than that of the inner wall, and an air insulation layer is provided at the bottom of the water-cooled screen body.

[0009] Optionally, in the above-mentioned water-cooled screen, the thickness of the outer wall is 3 to 5 times the thickness of the inner wall.

[0010] Optionally, in the above-mentioned water-cooled screen, the air insulation layer is an annular cavity disposed between the inner wall and the bottom wall.

[0011] Optionally, in the above-mentioned water-cooled screen, the thickness of the air insulation layer is 1mm to 3mm.

[0012] Optionally, in the above-mentioned water-cooled screen, the roughness of the outer surface of the outer wall is less than the roughness of the inner surface of the inner wall.

[0013] Optionally, in the above-mentioned water-cooled screen, the outer surfaces of the outer wall and the bottom wall are treated by polishing, grinding, spraying, or laser treatment.

[0014] Optionally, in the above-mentioned water-cooled screen, the inner surface of the inner wall is treated by wire drawing or sandblasting.

[0015] Optionally, in the above-mentioned water-cooled screen, the water-cooled screen includes an inlet pipe and an outlet pipe that communicate with the receiving cavity of the water-cooled screen body.

[0016] Optionally, in the above-mentioned water-cooled screen, a liquid flow channel is provided inside the receiving cavity.

[0017] A single crystal furnace includes a crucible, a flow guide tube, and the aforementioned water-cooled screen. The flow guide tube is disposed outside the water-cooled screen, and the flow guide tube and the water-cooled screen are disposed above the crucible.

[0018] As can be seen from the above solutions, the water-cooled screen disclosed in this utility model increases thermal resistance by increasing the thickness of its outer wall, reducing heat transfer from the thermal field to the water-cooled screen. By setting an air insulation layer, it weakens radiative heat transfer from the molten silicon to the water-cooled screen, ensuring the cooling effect of the water-cooled screen on the monocrystalline silicon rod, reducing the energy consumption of the heater to compensate for heat loss, reducing the oxygen content of the monocrystalline silicon rod, and thus improving the growth rate of the monocrystalline silicon rod. The monocrystalline furnace disclosed in this utility model has the same technical effects as the water-cooled screen, and will not be described further. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the structure of the water-cooled screen disclosed in an embodiment of the present utility model;

[0021] Figure 2 for Figure 1 A magnified view of part A in the image;

[0022] Among them, 10 is the water-cooled screen body, 11 is the inner wall, 12 is the outer wall, 13 is the air insulation layer, 14 is the bottom wall, 20 is the liquid inlet pipe, 30 is the liquid outlet pipe, and 40 is the liquid flow channel. Detailed Implementation

[0023] The core of this invention lies in disclosing a water-cooled screen to reduce the oxygen content of monocrystalline silicon rods and increase the growth rate of monocrystalline silicon rods.

[0024] Another key aspect of this invention is the disclosure of a single-crystal furnace including the aforementioned water-cooled screen.

[0025] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0026] This utility model discloses a single crystal furnace, including a crucible, a flow guide tube, and a water-cooled screen. The flow guide tube is disposed outside the water-cooled screen, and the flow guide tube and the water-cooled screen are disposed above the crucible.

[0027] It should be noted that in the Czochralski method for growing single-crystal silicon, polycrystalline silicon material is placed in a crucible, and a heater heats the polycrystalline silicon material in the crucible into a silicon melt. The single-crystal silicon rod grows upwards from the crucible. A water-cooled screen surrounds the single-crystal silicon rod to remove its latent heat of crystallization. Some of the heat from the silicon melt is transferred to the flow guide tube and water-cooled screen located above the silicon melt via radiation. Simultaneously, the flow guide tube further transfers the absorbed heat to the water-cooled screen, causing its temperature to rise. This reduces the water-cooled screen's heat absorption capacity for the single-crystal silicon rod, thus slowing down its growth rate. Furthermore, heat loss from the silicon melt necessitates increasing the heater power to replenish the lost heat. Increased heater power leads to a rise in the crucible wall temperature, ultimately increasing the oxygen content of the single-crystal silicon rod.

[0028] This invention is an improvement made by reducing the heat transfer from the silicon melt and the guide tube to the water-cooled screen, thereby enhancing the cooling effect of the water-cooled screen on the single crystal silicon rod.

[0029] like Figure 1As shown in the figure, this utility model discloses a water-cooled screen, including a water-cooled screen body 10. The water-cooled screen body 10 is a cylindrical structure with two through ends, surrounding a single-crystal silicon rod. The water-cooled screen body 10 includes an inner wall 11, an outer wall 12, and a bottom wall 14. The inner wall 11 and the outer wall 12 are arranged sequentially from the inside to the outside. The inner wall 11 is located close to the single-crystal silicon rod, and the outer wall 12 is located away from the single-crystal silicon rod. A receiving cavity is formed between the inner wall 11, the outer wall 12, and the bottom wall 14. The receiving cavity is used to introduce a cooling medium, which is used to remove the latent heat of crystallization of the single-crystal silicon rod. The thickness of the outer wall 12 is greater than the thickness of the inner wall 11, and an air insulation layer 13 is provided at the bottom of the water-cooled screen body 10. It should be noted that the air insulation layer 13 is preferably located on the side of the water-cooled screen body 10 facing the silicon melt.

[0030] The large thickness of the outer wall 12 increases the thermal resistance and reduces the heat transfer from the guide tube to the water-cooled screen body 10. The air insulation layer 13 weakens the heat radiation from the silicon melt to the water-cooled screen body 10, ensuring the cooling effect of the water-cooled screen body 10 on the monocrystalline silicon rod, reducing the energy consumption of the heater to compensate for the heat loss, reducing the oxygen content of the monocrystalline silicon rod, and improving the growth rate of the monocrystalline silicon rod.

[0031] The water-cooled screen disclosed in this embodiment of the utility model can increase the thermal resistance by increasing the thickness of the outer wall 12, thereby reducing the heat transfer from the thermal field to the water-cooled screen. By setting the air insulation layer 13, the radiative heat transfer from the silicon melt to the water-cooled screen can be weakened, ensuring the cooling effect of the water-cooled screen on the monocrystalline silicon rod, reducing the energy consumption of the heater to compensate for the heat loss, reducing the oxygen content of the monocrystalline silicon rod, and improving the growth rate of the monocrystalline silicon rod.

[0032] Furthermore, the thickness of the outer wall 12 is preferably set to be 3 to 5 times the thickness of the inner wall 11.

[0033] Furthermore, the air insulation layer 13 is an annular cavity disposed between the inner wall 11 and the outer wall 12.

[0034] Furthermore, the thickness of the air insulation layer 13 is 1mm to 3mm, and the specific thickness can be set according to actual needs.

[0035] Furthermore, in order to enhance the reflection effect of the outer wall 12 on the thermal radiation of the silicon melt and return the thermal radiation of the silicon melt to the thermal field, while strengthening the absorption of the thermal radiation of the monocrystalline silicon rod by the inner wall 11, the roughness of the outer surface of the outer wall 12 is less than the roughness of the inner surface of the inner wall 11. It should be noted that the roughness here refers to the roughness obtained under the same or nearly the same environment, the inner surface refers to the surface close to the monocrystalline silicon rod, and the outer surface refers to the surface far away from the monocrystalline silicon rod.

[0036] Furthermore, in some other specific embodiments, a reflective coating can be provided on the outer surface of the outer wall 12 to further increase the reflective effect of the outer wall 12 on the thermal radiation of the silicon melt.

[0037] Furthermore, the roughness of the outer surfaces of the outer wall 12 and the bottom wall 14 can be reduced by polishing, grinding, spraying, or laser treatment. By reducing the roughness of the outer surfaces of the outer wall 12 and the bottom wall 14, the reflection effect of the water-cooled screen body 10 on the thermal radiation of the silicon melt can be enhanced, the heat dissipation of the silicon melt to the water-cooled screen body 10 can be reduced, and the cooling effect of the water-cooled screen body 10 on the single crystal silicon rod can be guaranteed.

[0038] Furthermore, the roughness of the inner surface of the inner wall 11 can be increased by wire drawing or sandblasting to enhance the radiative heat transfer of the monocrystalline silicon rod to the water-cooled screen body 10, ensure the cooling effect of the water-cooled screen body 10 on the monocrystalline silicon rod, and improve the cooling rate of the monocrystalline silicon rod.

[0039] Furthermore, in some specific embodiments, a heat-conducting element is provided on the inner surface of the inner wall 11, which can contact the monocrystalline silicon rod to enhance the heat transfer between the monocrystalline silicon rod and the inner wall 11, thereby further enhancing the cooling effect of the water-cooled screen body 10 on the monocrystalline silicon rod.

[0040] Furthermore, the water-cooled screen includes an inlet pipe 20 and an outlet pipe 30 that are connected to the receiving cavity of the water-cooled screen body 10. The cooling medium enters the receiving cavity through the inlet pipe 20 and flows out through the outlet pipe 30 to cool the single crystal silicon rod.

[0041] Furthermore, in order to guide the flow of the cooling medium, a liquid flow channel 40 is provided in the cavity, along which the cooling medium can flow to cool the single crystal silicon rod.

[0042] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0043] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and 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, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0044] This article uses specific examples to illustrate the principles and implementation methods of this utility model. The descriptions of the above embodiments are only for the purpose of helping to understand the core ideas of this utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made to this utility model without departing from the principles of this utility model, and these improvements and modifications also fall within the protection scope of the claims of this utility model.

Claims

1. A water cooled panel, characterized by, The water cooling shield comprises a water cooling shield body (10), which is a through-cylinder structure, and comprises an inner wall (11), an outer wall (12) and a bottom wall (14), which enclose a containing cavity, the thickness of the outer wall (12) is greater than that of the inner wall (11), and the bottom of the water cooling shield body (10) is provided with an air insulation layer (13).

2. The water cooled panel of claim 1 wherein, The thickness of the outer wall (12) is 3-5 times that of the inner wall (11).

3. The water cooled panel of claim 1 wherein, The air insulation layer (13) is an annular cavity arranged between the inner wall (11) and the bottom wall (14).

4. The water cooled panel of claim 3 wherein, The thickness of the air insulation layer (13) is 1-3 mm.

5. The water cooled panel of claim 1 wherein, The roughness of the outer surface of the outer wall (12) is less than that of the inner surface of the inner wall (11).

6. The water cooled panel of claim 5 wherein, The outer surfaces of the outer wall (12) and the bottom wall (14) are treated by polishing, grinding, spraying or laser.

7. The water cooled panel of claim 6 wherein, The inner surface of the inner wall (11) is treated by wire drawing or sand blasting.

8. A water cooled panel as claimed in any one of claims 1 to 7, wherein, The water cooling shield comprises a liquid inlet pipe (20) and a liquid outlet pipe (30) which communicate with the containing cavity of the water cooling shield body (10).

9. The water cooled panel of claim 8 wherein, A liquid flow channel (40) is arranged in the containing cavity.

10. A single crystal furnace characterized by comprising: The single crystal furnace comprises a crucible, a flow guide cylinder and the water cooling shield according to any one of claims 1-9, the flow guide cylinder is arranged outside the water cooling shield, and the flow guide cylinder and the water cooling shield are arranged above the crucible.

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