A single crystal furnace

Abstract

The application provides a single crystal furnace, which comprises a furnace body, wherein the furnace body comprises a furnace cylinder, the furnace cylinder has an annular containing cavity, a plurality of spiral arranged baffles are arranged in the containing cavity, and the baffles divide the containing cavity into spiral-shaped water channels; the axial direction of the furnace cylinder is a first direction, the containing cavity comprises at least two cooling units distributed along the first direction, at least one water inlet is arranged at the bottom of the containing cavity, and at least one water outlet is arranged in each cooling unit; the water inlet is used for feeding cooling liquid into the cooling unit, and the water outlet is used for discharging the cooling liquid from the cooling unit. The single crystal furnace provided by the application can reduce the dissolution and transportation of oxygen to a certain extent, reduce the oxygen content of the tail of the single crystal silicon rod, and improve the product quality of the single crystal silicon rod.

Description

Technical Field

[0001] This application belongs to the field of photovoltaic manufacturing technology, specifically relating to a single crystal furnace. Background Technology

[0002] Monocrystalline silicon rods, used in the processing of silicon wafers, have a significant impact on the quality of subsequent silicon wafers and solar cells. For example, the oxygen content and distribution of monocrystalline silicon rods significantly affect the purity, electrical properties, and mechanical strength of silicon wafers. Excessive oxygen content can lead to the formation of electrically active oxygen donors, increasing carrier recombination and reducing wafer quality. Therefore, the performance of monocrystalline silicon rods has received widespread attention.

[0003] In existing technologies, with proper matching of process parameters, the oxygen content in the first half of the monocrystalline silicon rod pulling process can usually be controlled within a reasonable range. However, as the pulling process progresses into the second half, oxygen in the crucible accelerates its entry into the monocrystalline silicon rod, causing an increase in oxygen content at the tail end. Uncontrolled oxygen content in the second half of the monocrystalline silicon rod pulling process can severely impact product quality. Utility Model Content

[0004] This application aims to provide a single crystal furnace to solve the problem that the oxygen content in the latter half of the process of pulling single crystal silicon rods is easily out of control in existing single crystal furnaces.

[0005] To solve the above-mentioned technical problems, this application is implemented as follows:

[0006] This application discloses a single crystal furnace, which includes:

[0007] The furnace body includes a furnace cylinder with an annular receiving cavity. Multiple spirally arranged baffles are provided inside the receiving cavity, dividing the receiving cavity into spiral water channels.

[0008] The furnace cylinder has an axial direction in the first direction, the accommodating cavity includes at least two cooling units distributed along the first direction, the bottom of the accommodating cavity is provided with at least one water inlet, and each cooling unit is provided with at least one water outlet;

[0009] The inlet is used to introduce cooling liquid into the cooling unit, and the outlet is used to discharge the cooling liquid from the cooling unit.

[0010] Optionally, at least two of the water outlets have a height difference in the first direction, and the water outlets at different heights correspond to different cooling units on the furnace cylinder.

[0011] Optionally, at least one of the two water outlets includes a first water outlet and a second water outlet. Along the first direction, the first water outlet and the second water outlet are located above the water inlet, and the first water outlet is located above the second water outlet.

[0012] The height of the furnace cylinder is the first height H, the height difference between the water inlet and the first water outlet is the first height difference ΔH1, and the height difference between the second water outlet and the first water outlet is the second height difference ΔH2.

[0013] The following conditions must be met: the value range of ΔH1 / ΔH2 is 0.3–0.5; the value range of ΔH2 / H is 0.65–0.75; and the value range of ΔH1 / H is 0.25–0.35.

[0014] Optionally, the height of the water channel is a second height d, which refers to the distance between adjacent baffles along the furnace cylinder axis; the second height d satisfies the following: the value range of ΔH1 / d is 3-5; the value range of ΔH2 / d is 8-12.

[0015] Optionally, at least two of the water outlets further include a third water outlet, located between the first water outlet and the second water outlet along the first direction; wherein,

[0016] The height difference between the inlet and the first outlet is the first height difference ΔH1, the height difference between the second outlet and the first outlet is the second height difference ΔH2, and the height difference between the second outlet and the third outlet is the third height difference ΔH3.

[0017] The following condition must be met: the value of ΔH3 / H is in the range of 0.15–0.25.

[0018] Optionally, the height of the third water outlet relative to the furnace body is H / 2.

[0019] Optionally, the furnace cylinder has an annular receiving cavity, and at least one partition plate is disposed in the receiving cavity, the partition plate dividing the receiving cavity into at least two sub-receiving cavities distributed along the first direction;

[0020] Each of the sub-cavities forms a corresponding cooling unit, each cooling unit having at least one water inlet and at least one water outlet, and in each cooling unit, the water outlet is located above the water inlet.

[0021] Optionally, along the first direction, the uppermost cooling unit is the first cooling unit, and the lower cooling unit is the second cooling unit, wherein the height of the water channel of the first cooling unit is less than the height of the water channel of the second cooling unit.

[0022] Optionally, along the first direction, the uppermost cooling unit is a first cooling unit. The first cooling unit also has an air inlet and an air outlet communicating with the sub-receiving cavity. The air inlet is used to introduce cooling gas into the first cooling unit, and the air outlet is used to discharge the cooling gas from the first cooling unit.

[0023] Optionally, in the first cooling unit, along the first direction, the water outlet is located above the water inlet, and the air outlet is located above the air inlet; an airflow pipe is provided in the first cooling unit, which is connected to the air inlet and the air outlet respectively.

[0024] In this embodiment, the single-crystal furnace has multiple cooling units arranged along the axial direction of the furnace cylinder. Each cooling unit has at least one outlet for discharging cooling liquid. In specific applications, the cooling efficiency of the cooling unit can be adjusted by regulating the flow rate and velocity of the cooling liquid discharged from the outlet. With the cooling unit distribution determined in this embodiment, a temperature gradient can be formed along the first direction on the furnace cylinder by adjusting the cooling efficiency of at least two cooling units along the first direction. During the pulling process of the single-crystal silicon rod, especially after the pulling process enters the latter half, the temperature of the corresponding area of ​​each cooling unit within the furnace cylinder can be adjusted by regulating the cooling efficiency of the cooling units. This reduces the temperature in the crucible area during the later stages of crystal pulling, thereby reducing oxygen dissolution and transport within the crucible to some extent, decreasing the oxygen content at the tail of the single-crystal silicon rod, and improving the product quality of the single-crystal silicon rod.

[0025] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0026] The above and / or additional aspects and advantages of this utility model will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0027] Figure 1 This is a schematic diagram of the structure of a single crystal furnace as described in an embodiment of this application;

[0028] Figure 2 yes Figure 1 The diagram shows the structural diagram of the furnace body in the single crystal furnace;

[0029] Figure 3 This is one of the structural schematic diagrams of the furnace cylinder of a single crystal furnace described in the embodiments of this application;

[0030] Figure 4 This is a second schematic diagram of the structure of the furnace cylinder of a single crystal furnace as described in the embodiments of this application;

[0031] Figure 5 This is the third schematic diagram of the structure of the furnace cylinder of a single crystal furnace as described in the embodiments of this application;

[0032] Figure 6 This is the fourth schematic diagram of the structure of the furnace cylinder of a single crystal furnace as described in the embodiments of this application;

[0033] Figure 7 This is the fifth schematic diagram of the furnace cylinder structure of a single crystal furnace described in the embodiments of this application.

[0034] Reference numerals: 1 - Furnace body, 11 - Furnace cylinder, 12 - Furnace cover, 121 - Furnace cover water inlet, 122 - Furnace cover water outlet, 13 - Furnace bottom plate, 131 - Furnace bottom water inlet, 132 - Furnace bottom water outlet, 110 - Receiving cavity, 1101 - Sub-receiving cavity, 111 - Baffle plate, 112 - Water inlet, 113 - Water outlet, 1131 - First water outlet, 1132 - Second water outlet, 1133 - Third water outlet, 114 - Baffle plate, 115 - Air inlet, 116 - Air outlet, 2 - Crucible, 3 - Heater, X - First direction. Detailed Implementation

[0035] The embodiments of this utility model will now be described in detail. 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 below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model. All other embodiments obtained by those skilled in the art based on the embodiments in this application without inventive effort are within the scope of protection of this application.

[0036] The terms "first" and "second" in the specification and claims of this application may explicitly or implicitly include one or more of the features. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0037] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", 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 are not intended to 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.

[0038] 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.

[0039] Reference Figure 1 The diagram shows a structural schematic of a single crystal furnace according to an embodiment of this application. (Refer to...) Figure 2 , showed Figure 1 The schematic diagram of the single crystal furnace body shown is for reference. Figure 2 This shows one of the structural schematic diagrams of the furnace cylinder of a single crystal furnace according to an embodiment of this application. (Refer to...) Figure 3 The diagram shows a second schematic diagram of the structure of the furnace cylinder of a single crystal furnace according to an embodiment of this application.

[0040] This application provides a single crystal furnace, which can be used to pull single crystal silicon rods. Specifically, as shown in the embodiment... Figure 1 As shown, the single crystal furnace may specifically include: a furnace body 1, which may include a furnace cylinder 11. The furnace cylinder 11 has an annular receiving cavity 110, and a plurality of spirally arranged baffles 111 are provided inside the receiving cavity 110, dividing the receiving cavity 110 into spiral water channels. The axial direction of the furnace cylinder 11 is a first direction X. The receiving cavity 110 may include at least two cooling units distributed along the first direction X. At least one water inlet 112 is provided at the bottom of the receiving cavity 110, and each cooling unit is provided with at least one water outlet 113. The water inlet 112 can be used to introduce cooling liquid into the cooling unit, and the water outlet 113 can be used to discharge the cooling liquid from the cooling unit.

[0041] As an optional embodiment, the furnace body 1 includes a furnace cylinder 11 with an annular receiving cavity. Multiple spirally arranged baffles are disposed within the receiving cavity, dividing the receiving cavity into spiral water channels. The baffles are arranged circumferentially around the receiving cavity and, along the axial direction of the furnace cylinder, divide the furnace cylinder into multiple water channels; wherein the space between adjacent baffles constitutes the water channel; as an example, considering the flow resistance and cooling capacity of the cooling liquid in the water channel, the height of the water channel ranges from 105 to 135 mm; the thickness of the baffles in the axial direction of the furnace cylinder is selected to be 8-12 mm.

[0042] Typically, a crucible 2 is located in the middle of a single-crystal furnace, containing molten silicon. In the latter half of crystal growth, less silicon remains in the crucible, which still needs to be heated by the heater 3. This causes oxygen from the bottom of the crucible to rapidly enter the molten silicon, resulting in increased oxygen content at the tail of the grown silicon rod. This application's research found that the furnace cylinder 11 of a conventional single-crystal furnace includes an inlet and an outlet. Cooling liquid enters from the lower inlet and exits from the upper outlet, failing to create an effective temperature gradient along the furnace's axial direction. In the later stages of crystal growth, the bottom of the crucible is hotter, accelerating the entry of oxygen into the molten silicon, leading to higher oxygen content at the tail of the silicon rod. Therefore, this application, by incorporating multiple cooling units into the furnace cylinder 11, allows adjustment of the cooling efficiency of different units as crystal growth progresses into the latter half, thereby regulating the axial temperature gradient of the furnace cylinder and ensuring a lower temperature at the bottom of the crucible during this later stage of crystal growth.

[0043] In this embodiment, the single-crystal furnace has multiple cooling units arranged along the axial direction of the furnace cylinder 11. Each cooling unit has at least one outlet 113 for discharging cooling liquid. In specific applications, the cooling efficiency of the cooling unit can be adjusted by regulating the flow rate and velocity of the cooling liquid discharged from the outlet 113. By adjusting the cooling efficiency of at least two cooling units along the first direction X on the furnace cylinder 11, a temperature gradient can be formed along the first direction X on the furnace cylinder 11. During the pulling process of the single-crystal silicon rod, especially after the pulling process enters the latter half, the temperature of the corresponding area of ​​each cooling unit in the furnace cylinder 11 can be adjusted by regulating the cooling efficiency of the cooling units. In this way, the dissolution and transport of oxygen in the crucible can be reduced to a certain extent, the oxygen content at the tail of the single-crystal silicon rod can be reduced, and the product quality of the single-crystal silicon rod can be improved.

[0044] Moreover, in this embodiment, at least two cooling units are formed in the annular receiving cavity 110 within the furnace cylinder 11. The formation of the cooling units on the furnace cylinder 11 is relatively simple, and the structure of the furnace cylinder 11 is relatively simple and easy to implement.

[0045] In specific applications, the furnace cylinder 11 can serve as the main structural component of the single crystal furnace, and a receiving space can be provided inside the furnace body 1. The receiving space can house components such as a crucible, heater, and insulation cylinder, and can also be used for the pulling operation of single crystal silicon rods. The furnace cylinder 11 serves as the main structural component of the furnace body 1. A furnace cover 12 is typically provided at the top of the furnace cylinder 11, and a furnace bottom plate 13 is typically provided at the bottom of the furnace cylinder 11. The furnace cylinder 11, furnace cover 12, and furnace bottom plate 13 can be enclosed to form the receiving space. The furnace cover 12 is provided with a furnace cover inlet 121 and a furnace cover outlet 122. The furnace cover inlet 121 is used to introduce cooling liquid into the furnace cover 12, and the furnace cover outlet 122 is used to discharge the cooling liquid from the furnace cover 12, thereby achieving cooling of the furnace cover 12. The furnace bottom plate 13 is provided with a furnace bottom water inlet 131 and a furnace bottom water outlet 132. The furnace bottom water inlet 131 can be used to introduce cooling liquid into the furnace bottom plate 13, and the furnace bottom water outlet 132 can be used to discharge the cooling liquid in the furnace bottom plate 13, so as to achieve cooling of the furnace bottom plate 13.

[0046] Specifically, such as Figure 2 and Figure 3 As shown, the furnace cylinder 11 may have an annular receiving cavity 110, within which multiple spirally arranged baffles 111 are disposed. The baffles 111 divide the receiving cavity 110 into spiral water channels. A water inlet 112 is provided at the bottom of the receiving cavity 110, allowing cooling liquid to enter the receiving cavity 110. Figure 1 As shown, at least two outlets 113 spaced apart along the first direction X can be provided on the furnace cylinder 11. The outlets 113 can be used to discharge the cooling liquid in the receiving cavity 110. Specifically, in this embodiment, multiple cooling units spaced apart along the first direction X can be provided in the receiving cavity 110. Each cooling unit is provided with at least one outlet 113. The outlet 113 can be equipped with a flow meter, valve, or other components to control the flow rate and / or velocity of the cooling liquid, so as to adjust the cooling efficiency of the cooling unit by adjusting the flow rate and / or flow of the cooling liquid discharged from the outlet 113. In this way, by adjusting the cooling efficiency of multiple cooling units, a longitudinal temperature gradient can be formed on the furnace cylinder 11 to reduce the dissolution and transport of oxygen, thereby reducing the oxygen content at the tail of the single crystal silicon rod.

[0047] In some optional embodiments of this application, at least two water outlets 113 have a height difference in the first direction X, and water outlets 113 at different heights correspondingly form different cooling units on the furnace cylinder 11. In practical applications, since the water outlets 113 can be used to discharge the cooling liquid, and the discharge flow rate and velocity of the cooling liquid can be adjusted to regulate the cooling capacity at the location of the water outlet 113, a cooling unit with independently adjustable cooling capacity can be formed at the location of the water outlet 113. Thus, by setting at least two water outlets 113 at two locations with a height difference, at least two cooling units can be formed at the location of the at least two water outlets 113.

[0048] In this embodiment of the application, by setting at least two outlets 113, at least two cooling units distributed along the first direction X can be formed in the receiving cavity 110 of the furnace cylinder 11. The formation of the cooling units is relatively simple and highly operable.

[0049] In specific applications, the inlet 112 can be located near the bottom of the furnace cylinder 11 to allow the cooling liquid to enter from the bottom of the receiving cavity 110. After spiraling upwards through the water channels within the receiving cavity 110, the cooling liquid can be discharged outside the receiving cavity 110 through the first outlet 1131 and / or the second outlet 1132. Specifically, as shown... Figure 2 As shown, the first water outlet 1131 can be located near the top of the furnace cylinder 11, and the second water outlet 1132 can be located between the first water outlet 1131 and the water inlet 112. In practical applications, the height of the second water outlet 1132 can correspond to the position where oxygen easily dissolves in the crucible when the single crystal silicon rod is pulled to the latter half; specifically, it can correspond to the arc-shaped part at the bottom of the crucible, so that the cooling unit formed by the second water outlet 1132 can separately cool the bottom of the crucible, reduce the temperature of the crucible, avoid the dissolution and transport of oxygen, and thus improve the quality of the single crystal silicon rod.

[0050] For example, in the latter half of crystal growth, the first outlet 1131 can be closed or throttled, while the inlet 112 and the second outlet 1132 remain open. The cooling liquid mainly circulates through the middle outlet. At this time, the cooling liquid temperature and the furnace wall temperature exhibit a low-temperature bottom and high-temperature top state, resulting in differences in the heat transfer temperature difference between the inside and outside of the furnace in different areas. The heat transfer also shows a distribution characteristic of being higher at the bottom and lower at the top. Simultaneously, the temperature distribution at the crucible changes, the temperature at the bottom of the crucible decreases, and the dissolution and transport of oxygen from the bottom of the quartz crucible are effectively controlled, leading to a synchronous decrease in the oxygen content of the silicon crystal.

[0051] like Figure 3As shown, at least two outlets 113 may include at least a first outlet 1131 and a second outlet 1132. Along the first direction X, the first outlet 1131 and the second outlet 1132 are located above the inlet 112, and the first outlet 1131 is located above the second outlet 1132. The height of the furnace cylinder 11 is a first height H, the height difference between the inlet 112 and the first outlet 1131 is a first height difference ΔH1, and the height difference between the second outlet 1132 and the first outlet 1131 is a second height difference ΔH2. The following conditions are met: the value range of ΔH1 / ΔH2 is 0.3-0.5; the value range of ΔH2 / H is 0.65-0.75; and the value range of ΔH1 / H is 0.25-0.35.

[0052] In practical applications, by adjusting the heights of the first outlet 1131 and the second outlet 1132, the position of the cooling unit formed on the furnace cylinder 11 can be adjusted to create different temperature gradients. Experimental data shows that when the values ​​of ΔH1 / ΔH2 are in the range of 0.3-0.5; ΔH2 / H are in the range of 0.65-0.75; and ΔH1 / H are in the range of 0.25-0.35, a relatively ideal temperature gradient can be formed along the first direction X of the furnace cylinder 11, thereby improving the quality of the single crystal silicon rod.

[0053] Table 1 shows the correspondence between the setting height of the second water outlet and the temperature gradient of the furnace drum.

[0054]

[0055] As shown in Table 1, when the second water outlet 1132 is provided, the temperature gradient on the furnace cylinder 11 is significantly better than that when the second water outlet 1132 is not provided. Moreover, when the location of the second water outlet 1132 meets the above-mentioned given range, the temperature gradient on the furnace cylinder 11 is significantly better than that when the second water outlet 1132 exceeds the given range.

[0056] Specifically, Example 1 is defined as having no second water outlet, Example 1 is defined as having a second water outlet within a given range, and Example 2 is defined as having a second water outlet outside the given range.

[0057] In Comparative Example 1, i.e., Table 1, when no second outlet is provided, the initial temperature refers to the water temperature at the inlet 112, the final temperature refers to the water temperature at the first outlet 1131, and the temperature gradient refers to the ratio of the temperature difference between the inlet 112 and the first outlet 1131 to the height of the furnace drum. For example, in Comparative Example 1, the inlet flow rate is 31-32 L / min, and the pressure is 0.28-0.3 MPa; the first outlet flow rate is 31-32 L / min, and the pressure is 0.26-0.29 MPa.

[0058] In Example 1, when the second outlet is within a given range, the initial temperature refers to the water temperature at the inlet 112, the final temperature refers to the water temperature at the first outlet 1131, and the temperature gradient refers to the ratio of the temperature difference between the inlet and the first outlet 1131 to the height of the furnace drum. For example, in this embodiment, the inlet flow rate is 31-32 L / min, and the pressure is 0.28-0.3 MPa; the first outlet 1131 has a flow rate of 9.5-9.6 L / min and a pressure of 0.27-0.28 MPa; and the second outlet 1132 has a flow rate of 22.4-22.5 L / min and a pressure of 0.28-0.29 MPa.

[0059] Comparative Example 2 illustrates a scenario where the second outlet exceeds a given range. Specifically, the second outlet is positioned higher than its existing location, such as ΔH2 / H being less than 0.65, for example, ΔH2 / H being 0.5. In Comparative Example 2, the initial temperature refers to the water temperature at inlet 112, and the final temperature refers to the water temperature at the first outlet 1131. The temperature gradient is the ratio of the temperature difference between inlet 112 and the first outlet 1131 to the furnace height. The flow rate at the first outlet 1131 is 11.1-11.2 L / min, and the pressure is 0.27-0.28 MPa; the flow rate at the second outlet 1132 is 23.8-23.8 L / min, and the pressure is 0.279-0.289 MPa.

[0060] Based on the above data analysis, it can be seen that by reasonably setting the position of the second outlet, the furnace cylinder 11 can be divided into different cooling units, and a large temperature gradient can be formed along the axial direction of the furnace cylinder. Furthermore, in Embodiment 1, Comparative Example 1, and Comparative Example 2, the same crystal pulling process was used to grow silicon rods of the same length, such as reaching 5300 mm. Adjusting the inlet and outlet of the furnace cylinder at the same given rod length, for example, when the rod length reaches 4000 mm, the pressure of the inlet and outlet is adjusted as described above; it can be seen that when the second outlet is within a given range, the oxygen content at the tail of the silicon rod can be reduced. For example, the above example shows the tail oxygen content data detected after growing 200 silicon rods.

[0061] For example, for a furnace drum 11 with a height H of 1900 mm or 2100 mm, the value of ΔH1 / ΔH2 can be any one of 0.3, 0.35, 0.4, 0.45 or 0.5, the value of ΔH2 / H can be any one of 0.65, 0.67, 0.70, 0.72 or 0.75, and the value of ΔH1 / H can be any one of 0.25, 0.29, 0.30, 0.32 or 0.35. In this embodiment of the application, no specific limitation is made in this regard.

[0062] In some optional embodiments of this application, the height of the water channel is a second height d, satisfying the following conditions: ΔH1 / d ranges from 3 to 5; ΔH2 / d ranges from 8 to 12. Experimental data shows that when the ratio of H1 / d to ΔH2 / d is too large, the cross-sectional area of ​​the cooling channel is small, and with a constant flow rate, the flow velocity increases, resulting in high flow resistance and significant resistance loss. When the ratio of H1 / d to ΔH2 / d is too small, the water temperature of the two cooling units is basically uniformly distributed, the temperature gradient is relatively small, and the adjustment effect cannot be achieved. Therefore, when the value of H1 / d is in the range of 3 to 5 and the value of ΔH2 / d is in the range of 8 to 12, the resistance of the cooling liquid in the channel is small, and a better temperature gradient can be obtained, resulting in a better adjustment effect on the cooling capacity of the furnace cylinder 11.

[0063] For example, the cooling channel height d = 120 ± 15 mm, ΔH1 = 400 mm, ΔH2 = 1000 mm; that is, ΔH2 / d = 1000 / 120 ≈ 8.33; ΔH1 / d = 400 / 120 ≈ 3.33, to meet the above requirements, so as to take into account both small flow resistance and better cooling capacity adjustment effect.

[0064] In some alternative embodiments of this application, such as Figure 4 As shown, at least two outlets 113 may also include a third outlet 1133, located between the first outlet 1131 and the second outlet 1132 along the first direction X. The height difference between the inlet 112 and the first outlet 1131 is the first height difference ΔH1, the height difference between the second outlet 1132 and the first outlet 1131 is the second height difference ΔH2, and the height difference between the second outlet 1132 and the third outlet 1133 is the third height difference ΔH3. The following conditions are met: ΔH1 / ΔH2 ranges from 0.3 to 0.5; ΔH2 / H ranges from 0.65 to 0.75; ΔH1 / H ranges from 0.25 to 0.35; and ΔH3 / H ranges from 0.4 to 0.6.

[0065] Figure 4 In the furnace cylinder 11 shown, the positions of the water inlet 112, the first water outlet 1131, and the second water outlet 1132 are as follows: Figure 3 The same applies to furnace cylinder 11 shown, and will not be described again here. Figure 3 Based on the furnace cylinder 11 shown, Figure 4The furnace cylinder 11 shown may also include a third outlet 1133, which is located between the first outlet 1131 and the second outlet 1132. In practical applications, the height of the second outlet 1132 can correspond to the position of the molten silicon in the crucible when oxygen is easily dissolved in the later stage of the single crystal silicon rod being drawn. This allows the molten silicon to be cooled separately by the cooling unit formed by the third outlet 1133, reducing the temperature below the liquid surface and creating a temperature distribution that is cool at the bottom and hot at the top. This reduces the dissolution and transport of oxygen in the molten silicon, thereby improving the quality of the single crystal silicon rod.

[0066] In practical applications, by adjusting the heights of the first outlet 1131, the second outlet 1132, and the third outlet 1133, the position of the cooling units formed on the furnace cylinder 11 can be adjusted to create different temperature gradients. Experimental data shows that when the values ​​of ΔH1 / ΔH2 are in the range of 0.3-0.5; ΔH2 / H are in the range of 0.65-0.75; ΔH1 / H are in the range of 0.25-0.35; and ΔH3 / H are in the range of 0.4-0.6, a relatively ideal temperature gradient can be formed along the first direction X of the furnace cylinder 11 to improve the quality of the single crystal silicon rod.

[0067] In some optional embodiments of this application, the height of the third outlet 1133 relative to the furnace cylinder is H / 2, that is, the third outlet 1133 is located at half the height of the furnace cylinder 11, so that the position of the third outlet 1133 can correspond well with the interface of the silicon liquid in the crucible. Thus, the cooling area that can be temperature controlled is located in the area near the liquid surface of the crucible. This area is closely related to the generation and transport of oxygen and can effectively suppress the dissolution and transport of oxygen.

[0068] For example, when the first height H of the furnace cylinder 11 is 1400mm, ΔH1 = 400mm, ΔH2 = 300mm, ΔH3 = 700mm, ΔH1 / H = 400 / 1400 ≈ 0.29, ΔH2 = 300 / 1400 ≈ 0.21, ΔH3 = 700 / 1400 = 0.5, which meets the above range. Therefore, a relatively ideal temperature gradient can be formed in the furnace cylinder 11 along the first direction X to improve the quality of the single crystal silicon rod.

[0069] Reference Figure 5 The third schematic diagram shows the structure of the furnace cylinder of a single crystal furnace according to an embodiment of this application. Figure 5As shown, the furnace cylinder 11 has an annular receiving cavity 110, and at least one partition plate 114 is provided in the receiving cavity 110. The partition plate 114 divides the receiving cavity 110 into at least two sub-receiving cavities 1101 distributed along a first direction X. Each sub-receiving cavity 1101 corresponds to one of the cooling units. Each cooling unit has at least one water inlet 112 and at least one water outlet 113. In each cooling unit, the water outlet 113 is located above the water inlet 112.

[0070] In practical applications, the receiving cavity 110 inside the furnace cylinder 11 is divided into two sub-receiving cavities 1101 by a partition plate 114. Each sub-receiving cavity 1101 is equipped with an independent inlet 112 and outlet 113 to individually control the flow rate and volume of the cooling liquid within each sub-receiving cavity 1101, thereby adjusting the cooling capacity. This allows each sub-receiving cavity 1101 to form a cooling unit capable of independent cooling capacity adjustment, which is beneficial for creating the required temperature gradient in the furnace cylinder 11, thereby reducing the oxygen content at the tail end of the single-crystal silicon rod.

[0071] In this embodiment, two independent cooling units can be formed by placing a partition plate 114 within the receiving cavity 110 of the furnace cylinder 11. This method is extremely simple and highly operable. The partition plate 114 can be connected to the furnace cylinder 11 by welding, snap-fitting, or fastener connection. In this embodiment, the connection method of the partition plate 114 on the furnace cylinder 11 is not specifically limited. Furthermore, the position of the partition plate 114 can be set according to actual conditions. For example, the partition plate 114 can be placed at half the height of the furnace cylinder 11 to divide the receiving cavity 110 within the furnace cylinder 11 into two cooling units of equal size. Alternatively, the partition plate 114 can also be placed near the top or bottom of the receiving cavity 110 as needed. In this embodiment, the position of the partition plate 114 within the receiving cavity 110 is not specifically limited.

[0072] It should be noted that, Figure 5 The illustration only shows the case where there is only one partition plate 114, that is, one partition plate 114 divides the receiving cavity 110 into two sub-receiving cavities 1101. However, in practical applications, the number of partition plates 114 can also be multiple. For example, by setting two partition plates 114 in the receiving cavity 110, the receiving cavity 110 can be divided into three sub-receiving cavities 1101, and each sub-receiving cavity 1101 is equipped with an independent water inlet 112 and water outlet 113. In this way, three cooling units can be formed in the receiving cavity 110 of the furnace cylinder 11. In practical applications, those skilled in the art can set the number of partition plates 114 according to actual needs. The embodiments of this application do not specifically limit the number of partition plates 114.

[0073] In specific applications, the inlet 112 and outlet 113 of each cooling unit can be set according to actual needs. It is only necessary to set the position of the inlet 112 to be lower than the position of the outlet 113.

[0074] Reference Figure 6 The fourth schematic diagram shows the structure of the furnace cylinder of a single crystal furnace according to an embodiment of this application. Figure 6 As shown, along the first direction X, the uppermost cooling unit is the first cooling unit, and the lowermost cooling unit is the second cooling unit. The height of the water channels in the first cooling unit is less than the height of the water channels in the second cooling unit, allowing for more precise temperature control. The water channel density of the first cooling unit is relatively greater than that of the second cooling unit, which is more conducive to controlling the temperature of different cooling units.

[0075] Reference Figure 7 The fifth schematic diagram shows the structure of the furnace cylinder of a single crystal furnace according to an embodiment of this application. Figure 7 As shown, along the first direction X, the uppermost cooling unit is the first cooling unit. The first cooling unit also has an air inlet 115 and an air outlet 116 communicating with the sub-receiving cavity 1101. The air inlet 115 is used to introduce cooling gas into the first cooling unit, and the air outlet 116 is used to discharge the cooling gas from the first cooling unit. By adding a cooling system that circulates cooling gas to the first cooling unit, the temperature regulation capability of the first cooling unit can be further increased, thereby facilitating more precise temperature control within the furnace drum 11.

[0076] It should be noted that in the first cooling unit, temperature control can be performed solely by the cooling gas, solely by the cooling liquid, or simultaneously by both the cooling liquid and the cooling gas. In this embodiment, no specific limitation is made on the temperature control method within the first cooling unit.

[0077] In some optional embodiments of this application, in the first cooling unit, along the first direction X, the water outlet 113 is located above the water inlet 112, the air outlet 116 is located above the air inlet 115, the air inlet 115 is located above the water inlet 112, and the air outlet 116 is located below the water outlet 113. This avoids interference between the cooling liquid flowing into the water inlet 112 and the cooling gas flowing into the air inlet 115, further enhancing the temperature regulation capability of the first cooling unit.

[0078] For example, in the first cooling unit, the air inlet 115 can be located 15-20mm above the water inlet 112, and the air outlet 116 can be located 15-20mm below the water outlet 113. The diameters of each inlet and outlet can be consistent or differentiated. This application embodiment does not limit this.

[0079] For example, the first cooling unit is provided with an airflow duct that is connected to an air inlet and an air outlet, respectively. During cooling adjustment, cooling liquid or cooling gas can be introduced into the first cooling unit simultaneously, or only cooling liquid or only cooling gas can be introduced, as needed.

[0080] In summary, the single crystal furnace described in the embodiments of this application may include at least the following advantages:

[0081] In this embodiment, the single-crystal furnace has multiple cooling units arranged along the axial direction of the furnace cylinder. Each cooling unit has at least one outlet for discharging cooling liquid. In specific applications, the cooling efficiency of the cooling unit can be adjusted by regulating the flow rate and velocity of the cooling liquid discharged from the outlet. By adjusting the cooling efficiency of at least two cooling units along the first direction on the furnace cylinder, a temperature gradient can be formed along the first direction on the furnace cylinder. During the pulling process of the single-crystal silicon rod, especially after the pulling process enters the latter half, the temperature of the corresponding area of ​​each cooling unit in the furnace cylinder can be adjusted by regulating the cooling efficiency of the cooling units. In this way, the dissolution and transport of oxygen can be reduced to a certain extent, the oxygen content at the tail of the single-crystal silicon rod can be reduced, and the product quality of the single-crystal silicon rod can be improved.

[0082] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0083] Although embodiments of the present invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A single crystal furnace, characterized in that, The single crystal furnace includes: The furnace body includes a furnace cylinder with an annular receiving cavity. Multiple spirally arranged baffles are provided inside the receiving cavity, dividing the receiving cavity into spiral water channels. The furnace cylinder has an axial direction in the first direction, the accommodating cavity includes at least two cooling units distributed along the first direction, the bottom of the accommodating cavity is provided with at least one water inlet, and each cooling unit is provided with at least one water outlet; The inlet is used to introduce cooling liquid into the cooling unit, and the outlet is used to discharge the cooling liquid from the cooling unit.

2. The single crystal furnace according to claim 1, characterized in that, At least two of the water outlets have a height difference in the first direction, and the water outlets at different heights form different cooling units on the furnace cylinder.

3. The single crystal furnace according to claim 2, characterized in that, Of the at least two water outlets, at least a first water outlet and a second water outlet are included. Along the first direction, the first water outlet and the second water outlet are located above the water inlet, and the first water outlet is located above the second water outlet. The height of the furnace cylinder is the first height H, the height difference between the water inlet and the first water outlet is the first height difference ΔH1, and the height difference between the second water outlet and the first water outlet is the second height difference ΔH2. The following conditions must be met: the value range of ΔH1 / ΔH2 is 0.3–0.5; the value range of ΔH2 / H is 0.65–0.75; and the value range of ΔH1 / H is 0.25–0.

35.

4. The single crystal furnace according to claim 3, characterized in that, The height of the waterway is the second height d, where the height of the waterway refers to the distance between adjacent baffles along the axial direction of the furnace shell; the second height d satisfies the following: the value range of ΔH1 / d is 3-5; the value range of ΔH2 / d is 8-12.

5. The single crystal furnace according to claim 3, characterized in that, Of the at least two water outlets, a third water outlet is also included, located between the first water outlet and the second water outlet along the first direction; wherein, The height difference between the inlet and the first outlet is the first height difference ΔH1, the height difference between the second outlet and the first outlet is the second height difference ΔH2, and the height difference between the second outlet and the third outlet is the third height difference ΔH3. The following condition must be met: the value of ΔH3 / H is in the range of 0.15–0.

25.

6. The single crystal furnace according to claim 5, characterized in that, The height of the third water outlet relative to the furnace body is H / 2.

7. The single crystal furnace according to claim 1, characterized in that, The furnace cylinder has an annular receiving cavity, and at least one partition plate is provided in the receiving cavity, which divides the receiving cavity into at least two sub-receiving cavities distributed along the first direction; Each of the sub-cavities forms a corresponding cooling unit, each cooling unit having at least one water inlet and at least one water outlet, and in each cooling unit, the water outlet is located above the water inlet.

8. The single crystal furnace according to claim 7, characterized in that, Along the first direction, the uppermost cooling unit is the first cooling unit, and the lower cooling unit is the second cooling unit, wherein the height of the water channel of the first cooling unit is less than the height of the water channel of the second cooling unit.

9. The single crystal furnace according to claim 7, characterized in that, Along the first direction, the uppermost cooling unit is the first cooling unit. The first cooling unit also has an air inlet and an air outlet communicating with the sub-receiving cavity. The air inlet is used to introduce cooling gas into the first cooling unit, and the air outlet is used to discharge the cooling gas from the first cooling unit.

10. The single crystal furnace according to claim 9, characterized in that, In the first cooling unit, along the first direction, the water outlet is located above the water inlet, and the air outlet is located above the air inlet; an airflow pipe is provided in the first cooling unit, which is connected to the air inlet and the air outlet respectively.

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