Heat exchanger, thermal field device and single crystal furnace

Abstract

The utility model provides a heat exchanger, a thermal field device and a single crystal furnace. The heat exchanger comprises a cylinder section and a tip section which are sequentially arranged along a first direction, the cylinder section is fixedly connected with the tip section; the first direction is the axial direction of the heat exchanger; the cylindrical section comprises a first inner wall and a first outer wall; and in the first direction, the orthographic projection of the peripheral surface of the tip section is located on the inner side of the orthographic projection of the first outer wall. According to the utility model, the longitudinal temperature of the crystal can be increased, and the transverse temperature gradient of a solid-liquid interface is reduced, so that high-quality rapid growth of the crystal is realized.

Description

Technical Field

[0001] The utility model relates to the technical field of crystal pulling, in particular to a heat exchanger, a thermal field device and a single crystal furnace. Background Art

[0002] Temperature control is crucial during single crystal growth. Heat exchange channels are located within the heat exchanger to cool the crystal and increase its growth rate. The thermal field formed by the heat shield and heat exchanger effectively regulates and maintains the temperature distribution within the single crystal furnace, ensuring temperature stability and uniformity during crystal growth.

[0003] Under the current trend of reducing costs and increasing efficiency, the most direct way to reduce costs in the Czochralski method is to improve production efficiency, and increasing the crystal growth rate is one of the most effective ways to improve production efficiency.

[0004] Currently, one approach is to increase the longitudinal temperature gradient by reducing the distance between the heat exchanger and the crystallization interface to increase the pulling speed. However, this will affect the stability of the solid-liquid interface temperature, which in turn affects the normal growth of the crystal, leading to problems such as an increased breakage rate during crystal growth, making it difficult to ensure the rapid growth of high-quality crystals. Utility Model Content

[0005] In view of the above problems, embodiments of the present invention are proposed to provide a heat exchanger, a thermal field device and a single crystal furnace that overcome the above problems or at least partially solve the above problems.

[0006] To solve the above-mentioned problem, the present invention discloses a heat exchanger in an embodiment, comprising a cylindrical section and a tip section arranged in sequence along a first direction; the cylindrical section is fixedly connected to the tip section; the first direction is the axial direction of the heat exchanger; the cylindrical section comprises a first inner wall and a first outer wall; a first heat exchange cavity is formed between the first inner wall and the first outer wall; along the first direction, an orthographic projection of an outer peripheral surface of the tip section is located inside the orthographic projection of the first outer wall;

[0007] The distance between the first inner wall and the first outer wall is d1, the distance between the outer circumference of the tip segment and the inner circumference of the tip segment is d2, and d1≥1.2d2.

[0008] In a second aspect, an embodiment of the present utility model discloses a thermal field device, comprising a heat shield and the above-mentioned heat exchanger; the heat shield is sleeved outside the heat exchanger.

[0009] In a third aspect, an embodiment of the present invention discloses a single crystal furnace, comprising the heat exchanger as described above.

[0010] The present invention has the following advantages:

[0011] In an embodiment of the present invention, one end of the tip segment is close to the cylindrical segment of the heat exchanger, and the other end is away from the cylindrical segment. The tip segment is disposed at the bottom of the cylindrical segment, so that the tip segment is closer to the solid-liquid interface, thereby shortening the longitudinal distance between the heat exchanger and the solid-liquid interface, facilitating an increase in the longitudinal temperature of the crystal and improving the growth rate of the crystal. Along a first direction, the orthographic projection of the outer peripheral surface of the tip segment is located inward of the orthographic projection of the first outer wall; and the spacing between the first inner wall and the first outer wall is greater than or equal to 1.2 times the spacing between the outer peripheral surface of the tip segment and the inner peripheral surface of the tip segment. This reduces the longitudinal distance between the bottom of the tip segment and the crystallization region, while also reducing the lateral distance between the outer wall of the tip segment and the crystallization region. This can reduce the influence of the tip segment on the temperature of the solid-liquid interface outside the crystallization region, improve the temperature stability of the solid-liquid interface, and enable high-quality crystal growth. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a structural diagram of a heat exchanger of the utility model;

[0013] Figure 2 This is a front view of a heat exchanger of the present utility model;

[0014] Figure 3 This is a partial enlarged view of a heat exchanger of the present utility model;

[0015] Figure 4 This is a partial cross-sectional view of a heat exchanger and heat shield combination of the present invention;

[0016] Figure 5 It is a partially enlarged cross-sectional view of a heat exchanger and heat shield combination of the present invention;

[0017] Figure 6A It is a heat map of the existing thermal field device;

[0018] Figure 6B It is a heat map of the thermal field device of the present utility model.

[0019] Description of reference numerals:

[0020] 100. Heat exchanger; 1. Cylindrical section; 11. First inner wall; 12. First outer wall; 13. First heat exchange channel; 14. First heat exchange cavity; 2. Tip section; 21. Second inner wall; 22. Second outer wall; 222. Vertical wall; 223. Second conical wall; 23. Second heat exchange channel; 24. Second heat exchange cavity; 31. Liquid inlet pipe; 32. Liquid outlet pipe; 4. Transition section; 41. First conical wall; 200. Heat shield; 210. Inner liner; 220. Outer liner; 230. Insulation component. DETAILED DESCRIPTION

[0021] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0022] The terms "first" and "second" in the specification and claims of this application may explicitly or implicitly refer to one or more of these features. In the description of this utility model, unless otherwise specified, "plurality" means two or more. Furthermore, "and / or" in the specification and claims refers to at least one of the connected items, and the character " / " generally indicates an "or" relationship between the connected items.

[0023] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "thickness", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation to the present invention.

[0024] In the description of this utility model, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections, electrical connections; direct connections, indirect connections through an intermediate medium, and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on the specific circumstances.

[0025] In the first aspect, one of the core concepts of the embodiment of the present invention is to disclose a heat exchanger 100, such as Figure 1 As shown, the heat exchanger 100 comprises: a cylindrical section 1 and a tip section 2 arranged sequentially along a first direction; the cylindrical section 1 and the tip section 2 are fixedly connected and remain relatively stationary. The cylindrical section 1 comprises a first inner wall 11 and a first outer wall 12, forming a first heat exchange chamber 14 between the first inner wall 11 and the first outer wall 12. Along the first direction, the orthographic projection of the outer circumference of the tip section 2 is located inward of the orthographic projection of the first outer wall 12. The distance between the first inner wall 11 and the first outer wall 12 is d1, and the distance between the outer circumference of the tip section 2 and the inner circumference of the tip section 2 is d2, where d1 ≥ 1.2d2.

[0026] In an embodiment of the present invention, the upper end of the tip segment 2 is close to the cylindrical segment 1, and the lower end of the tip segment 2 is away from the cylindrical segment 1. The tip segment 2 is arranged at the bottom of the cylindrical segment 1, so that the tip segment 2 is closer to the solid-liquid interface, thereby shortening the longitudinal distance between the heat exchanger 100 and the solid-liquid interface, facilitating an increase in the longitudinal temperature of the crystal and improving the growth rate of the crystal. Along the first direction, the orthographic projection of the outer peripheral surface of the tip segment 2 falls inside the orthographic projection of the outer wall of the cylindrical segment 1, so that the longitudinal distance between the bottom of the tip segment 2 and the crystallization region is reduced, and the lateral distance between the tip segment 2 and the crystallization region is also reduced, that is, the lateral distance between the outer wall of the tip segment 2 and the crystallization region is also reduced. This can reduce the influence of the tip segment 2 on the temperature of the solid-liquid interface outside the crystallization region, improve the temperature stability of the solid-liquid interface, and achieve high-quality growth.

[0027] Optionally, the distance between the first inner wall 11 and the first outer wall 12 of the cylindrical segment 1 is d1, and the distance between the outer circumference of the tip segment 2 and the inner circumference of the tip segment 2 is d2, where d1 ≥ 1.2d2. The outer circumference of the tip segment 2 is the outer circumference of the second outer wall 22 of the tip segment 2; the inner circumference of the tip segment 2 is the inner circumference of the second inner wall 21 of the tip segment 2, specifically the inner circumference on the side closest to the crystal ingot.

[0028] In this embodiment, by defining the relationship between the distances d1 and d2, the tip segment 2 can be made thinner relative to the overall thickness of the cylindrical segment 1, thereby reducing the impact on the temperature of the solid-liquid interface outside the crystallization region. Experimental verification has shown that a value of d1 ≥ 1.2d2 reduces the impact on the temperature of the solid-liquid interface outside the crystallization region while increasing the casting speed.

[0029] As some optional embodiments, the tip section 2 can be a rotating body structure with a cavity structure, or a rotating body structure with a heat exchange tube arranged inside, etc. Of course, it can also be a solid cooling structure without a cavity inside; by limiting the relationship between the spacings d1 and d2, the tip section 2 can be made thinner than the overall thickness of the cylindrical section 1.

[0030] In an embodiment of the present invention, the tip segment 2 and the cylindrical segment 1 can be arranged sequentially along a first direction, and the tip segment 2 can be arranged at the bottom of the cylindrical segment 1. The tip segment 2 and the cylindrical segment 1 can be fixedly connected by splicing. For example, the cylindrical segment 1 and the tip segment 2 can be fixedly connected by welding, riveting, etc., that is, the heat exchanger 100 can be a split structure. Alternatively, the tip segment 2 and the cylindrical segment 1 can be integrally formed, that is, the heat exchanger 100 can also be a one-piece structure, further improving the structural stability of the heat exchanger 100. The cylindrical segment 1 and the tip segment 2 remain relatively stationary under all circumstances. The tip segment 2 and the cylindrical segment 1 can be made of stainless steel, copper, or aluminum alloy.

[0031] In the embodiment of the present invention, after the cylindrical segment 1 is connected to the tip segment 2, the tip segment 2 can be closer to the solid-liquid interface where the crystal grows, that is, the bottom of the tip segment 2 is at a smaller longitudinal distance from the crystallization region. The tip segment 2 can transfer heat to the cylindrical segment 1, thereby increasing the longitudinal temperature gradient of the crystal and further increasing the crystal growth rate.

[0032] In the embodiment of the present invention, the axial direction of the cylindrical segment 1 is defined as the first direction, which is consistent with the growth direction of the crystal. Figure 2 As shown, the first direction is the vertical direction, i.e., the longitudinal direction. Since along the first direction, the orthographic projection of the outer circumference of the tip segment 2 falls on the inner side of the orthographic projection of the outer wall of the cylindrical segment 1, that is, along the direction away from the cylindrical segment 1, the lateral distance between the outer circumference of the tip segment 2 and the crystallization region becomes smaller and smaller or within a limited distance range, the lateral temperature gradient of the solid-liquid interface can be reduced, and the temperature stability of the solid-liquid interface can be improved. In the actual crystal pulling process, the area affected by the heat absorption of the outer circumference of the tip segment 2 is mainly the melt liquid surface area on the solid-liquid interface that is outside the crystallization region. The temperature fluctuation of this area will affect the temperature fluctuation at the crystallization region, and thus affect the wire breakage rate of crystal growth. Therefore, in this embodiment, by controlling the longitudinal distance between the bottom of the tip segment 2 and the crystallization region and the lateral distance between the outer circumference of the tip segment 2 and the crystallization region, the pulling speed can be increased while reducing the impact on crystal growth.

[0033] The heat exchanger 100 described in this embodiment is applied to a thermal field environment to provide heat exchange during the crystal pulling process, or it can also be applied in other scenarios requiring heat exchange. The heat exchanger 100 can be specifically applied in the photovoltaic and semiconductor industries. The present embodiment of the utility model only uses the heat exchanger 100 as an example to increase the longitudinal temperature gradient of the crystal, improve the crystal growth rate, and ensure the stability of the solid-liquid interface, thereby ensuring the rapid growth of high-quality crystals and reducing production costs.

[0034] In the above embodiment or in other optional embodiments of the present invention, d1 is 30-45 mm and d2 is 4-25 mm. Here, d1 is the distance between the first inner wall 11 and the first outer wall 12, which are opposite to each other; d2 is the distance between the outer circumference of the tip section 2 and the inner circumference of the tip section 2.

[0035] In the embodiment of the present invention, the cylindrical section 1 includes a first inner wall 11 and a first outer wall 12, and a first heat exchange cavity 14 between the first inner wall 11 and the first outer wall 12. The distance d1 between the first inner wall 11 and the first outer wall 12 can be 30-45 mm to effectively ensure the heat exchange capacity of the cylindrical section 1.

[0036] Specifically, the distance d1 between the first inner wall 11 and the first outer wall 12 represents the thickness of the first heat exchange chamber 14, i.e., the radial dimension of the first heat exchange chamber 14 along the heat exchanger 100, which is related to the flow rate of the heat exchange medium. The thickness of the first heat exchange chamber 14 can be 28 mm, 30 mm, 35 mm, 36 mm, 43 mm, 45 mm, etc.

[0037] Specifically, as an optional embodiment, the tip segment 2 is a heat-conducting component with no cavity inside or only a small cavity. The distance between the outer peripheral surface of the tip segment 2 and the inner peripheral surface of the tip segment 2 is d2. By limiting the distance d2, on the one hand, it can avoid the tip segment 2 being too thin, which is not conducive to the control of the axial temperature gradient. On the other hand, it can avoid the radial thickness of the tip segment 2 being too thick, which is not conducive to the control of the lateral temperature gradient.

[0038] Specifically, as an optional embodiment, the tip section 2 can be a rotating body structure with a cavity structure, specifically including a second inner wall 21 and a second outer wall 22, and a second heat exchange cavity 24 between the second inner wall 21 and the second outer wall 22. The distance d2 between the outer circumference of the tip section 2 and the inner circumference of the tip section 2 can be the sum of the thicknesses of the second heat exchange cavity 24, the second inner wall 21 and the second outer wall 22. The thickness of the second heat exchange cavity 24, that is, the radial dimension of the second heat exchange cavity 24 along the heat exchanger 100. Specifically, the second inner wall 21 and the second outer wall 22 are made of a metal heat-conducting material such as stainless steel. The thickness of the second inner wall 21 and the second outer wall 22 can be 2-5 mm, preferably 3 mm; the radial dimension of the second heat exchange cavity 24 along the heat exchanger 100 is 3-15 mm, preferably 6 mm. According to the size of the second inner wall 21 and the second outer wall 22, the radial thickness of the second heat exchange chamber 24 can be limited by limiting d1 to be at least greater than or equal to 1.2 times d2. Of course, d1 can also be 1.5 times, 2 times, 2.5 times, 3 times, etc. of d2.

[0039] When the tip section 2 is a rotating body structure with a cavity structure, considering the impact on the solid-liquid interface and cooling water, if the second heat exchange cavity 24 is too thin, it will be difficult for cooling water to pass through and will be easily clogged. If the second heat exchange cavity 24 is too thick, the flow rate of the cooling water will be reduced, which will be detrimental to heat exchange. Moreover, the radial temperature gradient will become larger, resulting in excessive fluctuations in the solid-liquid interface, which will affect the success rate of crystal growth, especially the crystal growth in the shoulder release stage.

[0040] Specifically, the embodiment of the present invention limits the spacing between the outer circumference of the tip segment 2 and the inner circumference of the tip segment 2 to 4-25 mm, thereby effectively ensuring the heat exchange capacity of the tip segment 2 while reducing the impact on the radial temperature of the solid-liquid interface. After removing the thickness of the second inner wall 21 and the second outer wall 22, the spacing between the opposing surfaces of the second inner wall 21 and the second outer wall 22 is limited, i.e., the thickness of the second heat exchange chamber 24 is controlled to be 3-15 mm, thereby effectively ensuring the heat exchange capacity of the tip segment 2 while reducing the impact on the radial temperature of the solid-liquid interface. The thickness of the second heat exchange chamber 24 can be 2.5 mm, 3 mm, 4 mm, 7 mm, 11 mm, 12 mm, 15 mm, etc.

[0041] In the embodiment of the present invention, the first heat exchange channel 13 is used to pass and cool the growing crystal, thereby increasing the crystal growth rate. The tip section 2 can transfer heat to the first heat exchange cavity 14, which can effectively ensure the absorption of the latent heat of crystallization generated during the crystal growth process.

[0042] Specifically, the first inner wall 11 of the cylindrical section 1 is the first inner layer component, and the first outer wall 12 of the cylindrical section 1 is the first outer layer component; the first outer layer component is arranged outside the first inner layer component; that is, the cylindrical section 1 can be constructed of inner and outer layer components, and the first inner layer component can be enclosed to form a first heat exchange channel 13; a first heat exchange cavity 14 can be formed between the first inner layer component and the first outer layer component.

[0043] Specifically, if Figure 4 As shown, the first outer layer component can be sleeved on the outside of the first inner layer component, and the first outer layer component and the first inner layer component can be spaced apart to utilize the gap between the first inner layer component and the first outer layer component to prepare a first heat exchange cavity 14. The first heat exchange cavity 14 can be filled with a heat exchange medium, which can be a liquid or a gas, etc. The embodiment of the present utility model only takes the heat exchange medium as cooling water as an example for explanation, and other situations can refer to the settings.

[0044] Specifically, the first inner layer component and the first outer layer component can both be annular structures, and the first inner layer component and the first outer layer component can be evenly spaced so that the first heat exchange cavity 14 is a channel of equal thickness, and the thickness of the first heat exchange cavity 14 is the dimension along the radial direction of the heat exchanger 100.

[0045] Specifically, the cross-sectional shape of the cylindrical section 1 along the radial direction of the heat exchanger 100 may be a ring, and the cross-sectional shape of the first heat exchange channel 13 along the radial direction of the heat exchanger 100 may be a circle, which may be specifically set with reference to the shape of a crystal.

[0046] Alternatively, as Figure 1 and Figure 2As shown, the heat exchanger 100 may further include a liquid inlet pipe 31 and a liquid outlet pipe 32; the liquid inlet pipe 31 and the liquid outlet pipe 32 are both connected to the side of the cylindrical section 1 away from the tip section 2; the liquid inlet pipe 31 and the liquid outlet pipe 32 are both connected to the first heat exchange chamber 14.

[0047] In the embodiment of the present invention, heat exchange medium can be infused into the first heat exchange chamber 14 through the liquid inlet pipe 31 , and heat exchange medium discharged from the first heat exchange chamber 14 can be received through the liquid outlet pipe 32 .

[0048] Specifically, the liquid inlet pipe 31 is used to supply the heat exchange medium, and the liquid outlet pipe 32 is used to discharge the heat exchange medium. The heat exchange medium can also be pressurized to further increase its flow rate within the first heat exchange chamber 14. In this embodiment, the heat exchanger 100 includes not only the cylindrical section 1 and the tip section 2, but also a conical section above the cylindrical section 1. The liquid inlet pipe 31 and the liquid outlet pipe 32 communicate with the cylindrical section through the conical section.

[0049] Specifically, the latent heat of crystallization generated during the growth process of the crystal is transferred to the second inner wall 21 of the tip section 2 through radiation energy, and then conducted to the cooling water. The cooling water takes away the heat during the flow, thereby cooling the crystal.

[0050] Optionally, the first heat exchange chamber 14 may be filled with medium channels. For example, a spiral channel may be arranged within the first heat exchange chamber 14, allowing cooling water to enter the bottom of the cylindrical section 1 through the liquid inlet pipe 31, circulate in the spiral channel, and finally be discharged through the liquid outlet pipe 32. This can increase the flow path of the heat exchange medium and improve the heat exchange effect. Alternatively, the first heat exchange chamber 14 may be arranged with multiple spaced sub-channels, with adjacent sub-channels connected.

[0051] On the basis of the above embodiments or in other optional embodiments of the present invention, the tip section 2 may include a second inner wall 21 and a second outer wall 22; the outer wall of the tip section 2 is the second outer wall 22, which is arranged outside the second inner wall 21; the second inner wall 21 is enclosed to form a second heat exchange channel 23; the second heat exchange channel 23 and the first heat exchange channel 13 are connected along the first direction; and a second heat exchange cavity 24 is provided between the second inner wall 21 and the second outer wall 22.

[0052] In this embodiment of the present invention, the first heat exchange channel 13 and the second heat exchange channel 23 are relatively continuous along the first direction, and can be used to pass through the growing crystal to facilitate heat exchange with the crystal. A second heat exchange cavity 24 is provided between the second inner wall 21 and the second outer wall 22 to further enhance the heat exchange capacity of the tip section 2.

[0053] Optionally, the second inner wall 21 is fixedly connected to the first inner wall 11 , and the second outer wall 22 is fixedly connected to the first outer wall 12 , so as to achieve a fixed connection between the cylindrical segment 1 and the tip segment 2 .

[0054] Specifically, the second outer wall 22 of the tip section 2 is a second outer layer component, and the second inner wall 21 is a second inner layer component. The second outer layer component can be disposed outside the second inner layer component, that is, the tip section 2 can be constructed of an inner and outer layer component. The second inner layer component can be enclosed to form a second heat exchange channel 23, and a second heat exchange cavity 24 can be formed between the second inner layer component and the second outer layer component.

[0055] Specifically, if Figure 5 As shown, the second outer layer component can be sleeved on the outside of the second inner layer component; the second inner layer component encloses to form a second heat exchange channel 23; the gap between the second inner layer component and the second outer layer component can be used to form a second heat exchange cavity 24; the second heat exchange channel 23 is used to penetrate the growing crystal, so that the second inner layer component can be arranged around the crystal, so that the cooling water can also take away part of the crystallization latent heat during the flow in the second heat exchange cavity 24, which can further improve the cooling capacity of the heat exchanger 100 for the crystal.

[0056] Specifically, the tip section 2 is the part of the entire heat exchanger 100 structure that is closest to the solid-liquid interface. During the crystal growth process, the second inner layer component can transfer a portion of the crystallization latent heat to the second heat exchange chamber 24, thereby quickly taking away the crystallization latent heat during the crystal growth process, thereby increasing the crystal pulling speed.

[0057] The embodiment of the present invention is only illustrated by taking the heat exchanger 100 as a rotating body, that is, the cross-sectional shape of the first heat exchange channel 13 and the second heat exchange channel 23 is circular, so as to facilitate penetration into the crystal and avoid interference with the growth of the crystal.

[0058] Furthermore, the spacing between the first inner wall 11 and the first outer wall 12 is greater than the spacing between the second inner wall 21 and the second outer wall 22. This reduces the lateral distance (i.e., radial distance) between the outer wall of the tip segment 2 and the crystallization region. This facilitates reducing the lateral temperature gradient (i.e., radial temperature gradient) at the solid-liquid interface, thereby improving the temperature stability of the solid-liquid interface and ensuring high-quality crystal growth. In this embodiment, by adjusting the spacing between the first inner wall 11 and the first outer wall 12 to be greater than the spacing between the second inner wall 21 and the second outer wall 22, the heat exchange capacity of the tip segment 2 perpendicular to the first direction is reduced, thereby reducing the impact on the lateral temperature gradient at the solid-liquid interface.

[0059] Specifically, the longitudinal distance between the bottom of the tip segment 2 and the crystallization region becomes smaller, and the lateral size of the tip segment 2 becomes smaller when it approaches the crystallization region, which can increase the longitudinal temperature gradient of the crystal, while staying as far away from the solid-liquid interface outside the crystallization region as possible, reducing the radial temperature gradient of the solid-liquid interface.

[0060] Specifically, the tip section 2 can be positioned below the cylindrical section 1 to shorten the distance between the heat exchanger 100 and the solid-liquid interface in the first direction. This reduces the longitudinal distance between the heat exchanger 100 and the crystallization region, thereby increasing the longitudinal temperature gradient of the crystal. The distance from the tip section 2 to the solid-liquid interface is negatively correlated with the crystal growth rate: the smaller the distance, the greater the longitudinal temperature gradient and the higher the crystal growth rate.

[0061] Based on the above embodiment or in other optional embodiments of the present invention, the inner circumference of the second inner wall 21 is coplanar with the inner circumference of the first inner wall 11. Specifically, the second inner wall 21 and the first inner wall 11 can both be straight cylindrical structures and can be integrally formed into a straight cylindrical structure.

[0062] Optionally, the second heat exchange cavity 24 is in communication with a flow channel respectively provided in the first heat exchange cavity 14. Specifically, the first heat exchange cavity 14 is in communication with the second heat exchange cavity 24, so that the same cooling medium can be passed into the first heat exchange cavity 14 and the second heat exchange cavity 24, thereby improving the convenience of passing the cooling medium.

[0063] Optionally, the second heat exchange cavity 24 is not connected to the flow passages provided in the first heat exchange cavity 14. Specifically, the first heat exchange cavity 14 and the second heat exchange cavity 24 can be provided independently, and two cooling media can be respectively introduced into the first heat exchange cavity 14 and the second heat exchange cavity 24. This allows different cooling media to be introduced into the first heat exchange cavity 14 and the second heat exchange cavity 24, thereby facilitating the adjustment of the heat exchange capacity of the cylindrical section 1 and the tip section 2. Of course, the first heat exchange cavity 14 and the second heat exchange cavity 24 can also be provided with the same cooling medium.

[0064] Based on the above embodiment or in other optional embodiments of the present invention, the second outer wall 22 may also include only a vertical wall 222, the upper end of which is directly connected to the first outer wall 12 of the cylindrical segment 1. The distance d1 between the first inner wall 11 and the first outer wall 12 is greater than or equal to 1.2 times the distance d2 between the outer circumferential surface of the vertical wall 222 and the inner circumferential surface of the second inner wall.

[0065] In the above embodiment or in other optional embodiments of the present invention, the heat exchanger 100 includes a transition section 4; the cylindrical section 1 is fixedly connected to the tip section 2 via the transition section 4. The orthographic projection of the outer wall of the transition section 4 is located inward of the orthographic projection of the first outer wall 12, and the orthographic projection of the second outer wall 22 is located inward of the orthographic projection of the outer wall of the transition section 4.

[0066] In this embodiment of the present invention, the outer wall of the transition section 4 includes a first tapered wall 41, which is a cone. The transition section 4 includes at least one tapered portion. This compresses and narrows the heat exchange chamber away from the cylindrical section 1, causing the cooling water flow to shift from laminar to turbulent. The upper end of the vertical wall 222 is connected to the first tapered wall 41. The inner wall of the transition section 4 is coplanar with the second inner wall, forming a cylindrical structure.

[0067] Specifically, the outer wall of the transition section 4 is a first tapered wall 41, and the inner wall is a straight cylindrical wall. The orthographic projection of the outer wall of the transition section 4 is located inward of the orthographic projection of the first outer wall 12, and the orthographic projection of the second outer wall 22 is located inward of the orthographic projection of the outer wall of the transition section 4. This can reduce the impact on the lateral temperature gradient of the crystallization plane.

[0068] Based on the above embodiments or in other optional embodiments of the present invention, the second outer wall 22 includes a vertical wall 222 and a second conical wall 223; the upper end of the vertical wall 222 is fixedly connected to the first outer wall 12, and the lower end is fixedly connected to the second conical wall 223.

[0069] Specifically, the ends of the vertical wall 222 are connected to the first tapered wall 41 and the second tapered wall 223, respectively; the end of the first tapered wall 41 away from the vertical wall 222 is fixedly connected to the first outer wall 12. Alternatively, the upper end of the vertical wall 222 is directly connected to the first outer wall 12 of the cylindrical segment 1, and the lower end is fixedly connected to the second tapered wall 223.

[0070] Specifically, if Figure 3 As shown, in an embodiment of the present invention, along the direction away from the cylindrical section 1, the first conical wall 41, the vertical wall 222 and the second conical wall 223 are connected in sequence, and the diameter can first be reduced, then remain unchanged, and then reduced again, that is, the closer the heat exchanger 100 is to the solid-liquid interface, the smaller the lateral size of the heat exchanger 100, that is, the smaller the lateral distance between the outer peripheral surface of the heat exchanger 100 and the crystallization area, which is convenient for improving the temperature stability of the solid-liquid interface and ensuring high-quality crystal growth. At the same time, the vertical wall 222 serves as a transition area, and the thickness of the heat exchange cavity at the vertical wall 222 does not continue to decrease, which can ensure the heat exchange capacity of the tip section 2. Specifically, the length of the vertical wall 222 along the first direction can be 7-20mm. In this embodiment, the vertical wall 222 is connected between the first conical wall 41 and the second conical wall 223, and can also reduce the impact of the vertical wall 222 on the temperature of the solid-liquid interface.

[0071] Specifically, the bottom end of the second tapered wall 223 is closer to the solid-liquid interface, thereby increasing the longitudinal temperature gradient. As the diameter of the second tapered wall 223 decreases as it approaches the crystallization region of the crystal away from the cylindrical segment 1, it reduces the impact on the temperature outside the crystallization region at the solid-liquid interface and reduces the lateral temperature gradient at the solid-liquid interface.

[0072] Specifically, the extension lengths of the first tapered wall 41 , the vertical wall 222 , and the second tapered wall 223 in the first direction can be designed according to actual needs, and are not specifically limited in this embodiment of the present invention.

[0073] Specifically, if Figure 3 As shown, the second inner wall 21 extends along the first direction; the second conical wall 223 has an inclination angle with the first direction, and the inclination angle θ is 45-80°. On the one hand, it can ensure the heat exchange effect of the tip section 2, and on the other hand, it can also reduce the temperature influence of the second conical wall 223 on the solid-liquid interface, reduce the radial temperature gradient of the solid-liquid interface, and improve the temperature stability of the solid-liquid interface.

[0074] Based on the above embodiment or in other optional embodiments of the present invention, the length L of the tip section 2 along the first direction is 7-40 mm. The tip section 2 may include only the second inner wall and the vertical wall 222, or only the second inner wall, the second tapered wall 223, and the vertical wall 222. The heat exchanger 100 may include only the cylindrical section 1 and the tip section 2, or may include the cylindrical section 1, the transition section 4, and the tip section 2. The vertical wall 222 of the heat exchanger along the first direction may be 7-40 mm long. When including the first tapered wall 41 and the second tapered wall 223, the vertical wall 222 may further be 5-20 mm long.

[0075] On the basis of the above embodiments or in other optional embodiments of the present invention, the inner surface of the first inner wall 11 is provided with a first absorption coating, and the emissivity of the first absorption coating is 0.8-0.95. In this way, under the reflection effect of the first absorption coating, the cylindrical section 1 can better absorb radiation, thereby improving the heat exchange capacity of the heat exchanger 100, which is conducive to increasing the longitudinal temperature gradient of the crystal.

[0076] Specifically, the first absorption coating can be obtained by salt bath treatment, high temperature molten salt composite treatment PQP.

[0077] Optionally, the first outer wall 12 may be provided with a coating having an emissivity of less than 0.5, thereby reducing the heat absorption efficiency of the first outer wall 12 and reducing the impact of the first outer wall 12 on the temperature of the solid-liquid interface, thereby facilitating a reduction in the radial temperature gradient at the solid-liquid interface. Furthermore, the first outer wall 12 may be a polished surface having an emissivity of less than 0.5, thereby reducing the heat absorption efficiency of the first outer wall 12.

[0078] Optionally, the inner surface of the second inner wall 21 is provided with a second absorption coating, and the emissivity of the second absorption coating is 0.8-0.95, so that the tip section 2 can better absorb radiation, thereby improving the heat exchange capacity of the heat exchanger 100.

[0079] Specifically, the second absorbing coating layer can be set with reference to the first absorbing coating layer, and the embodiments of the present invention will not be described in detail.

[0080] Optionally, the second outer wall 22 may be provided with a coating having an emissivity of less than 0.5, thereby reducing the heat absorption efficiency of the second outer wall 22. This can reduce the impact of the second outer wall 22 on the temperature of the solid-liquid interface and help reduce the radial temperature gradient at the solid-liquid interface. Furthermore, the second outer wall 22 may be a polished surface having an emissivity of less than 0.5 to reduce the heat absorption efficiency of the second outer wall 22.

[0081] Optionally, along the first direction, a third absorption coating is provided at the end of the tip segment 2 away from one end of the cylindrical segment 1, so that the end of the tip segment 2 away from one end of the cylindrical segment 1 produces a reflection in the molten silicon liquid, thereby improving the convenience and reliability of collecting the liquid mouth distance.

[0082] Specifically, the end of the tip segment 2 away from one end of the cylindrical segment 1 is the bottom end surface of the tip segment 2 , ie, the surface closest to the solid-liquid interface.

[0083] Specifically, a CCD can be used to capture a reflection image of the end of the tip segment 2 away from the cylindrical segment 1 in the molten silicon liquid. Data processing can be performed to determine the liquid inlet distance between the bottom end of the tip segment 2 and the solid-liquid interface. A third absorbing coating can be provided at the end of the tip segment 2 away from the cylindrical segment 1 to improve image acquisition accuracy. Specifically, the third absorbing coating can be obtained by a blackening treatment.

[0084] Optionally, the emissivity of the third absorption coating is greater than 0.2 to improve the image clarity of the reflection of the end of the tip segment 2 away from the end of the cylindrical segment 1 in the molten silicon liquid.

[0085] Optionally, when the CCD cannot capture images, the crucible root ratio method can be used to calculate the crucible lifting speed V = crystal pulling speed * crucible root coefficient.

[0086] The heat exchanger described in the embodiment of the utility model has at least the following advantages:

[0087] In an embodiment of the present invention, one end of the tip segment is close to the cylindrical segment, and the other end of the tip segment is away from the cylindrical segment. The tip segment is arranged at the bottom of the cylindrical segment so that the tip segment is closer to the solid-liquid interface, thereby shortening the distance between the heat exchanger and the solid-liquid interface, facilitating an increase in the longitudinal temperature of the crystal and improving the growth rate of the crystal. Along the first direction, the orthographic projection of the outer peripheral surface of the tip segment 2 is located on the inner side of the orthographic projection of the first outer wall 12, so that the longitudinal distance between the bottom of the tip segment and the crystallization region is reduced, and the lateral distance between the outer wall of the tip segment and the crystallization region is also reduced, which can reduce the influence of the tip segment on the temperature of the solid-liquid interface outside the crystallization region, reduce the influence of the outer wall of the tip segment on the lateral temperature gradient of the solid-liquid interface, improve the temperature stability of the solid-liquid interface, and enable high-quality growth of crystals.

[0088] In a second aspect, an embodiment of the present invention further discloses a thermal field device, which may specifically include a heat shield 200 and the above-mentioned heat exchanger 100; the heat shield 200 is sleeved outside the heat exchanger 100.

[0089] Specifically, the heat shield 200 can provide a heat-insulating effect, and the heat exchanger 100 can provide a cooling effect.

[0090] Optionally, the heat shield 200 may include a heat preservation member 230 and an outer liner 220; the outer liner 220 is sleeved on the outside of the heat exchanger 100; along the first direction, the heat preservation member 230 is arranged between the cylindrical section 1 and the outer liner 220; the heat preservation member 230 is arranged relative to the second outer wall 22 of the tip section 2, and the heat preservation member 230 is provided with a step on the side close to the second outer wall 22, and the surface shape of the step matches the shape of the second outer wall 22, so that the heat preservation member 230 is structurally adapted to the tip section 2, and the heat preservation member 230 can have a good heat insulation effect on the tip section 2, which is beneficial to reducing the radial temperature gradient of the solid-liquid interface. Of course, the surface of the heat preservation member 230 close to the second outer wall 22 can also be set to a surface of other shapes, which can match the outer surface shape of the second outer wall 22. For example, when the second outer wall 22 is a cylindrical surface, the surface of the heat preservation member 230 close to the second outer wall 22 is a cylindrical surface.

[0091] Specifically, the insulation member is opposed to the second outer wall 22 and can be spaced apart from the second outer wall 22 to reduce the probability of collision between the insulation member 230 and the tip section 2, thereby preventing the generation of impurities. The surface shape of the insulation member 230 matches the shape of the second outer wall 22 of the heat exchanger 100, thereby blocking the insulation material between the second outer wall 22 and the outer liner 220, thereby preventing the insulation material from falling into the silicon melt.

[0092] Optionally, the heat shield 200 further includes an inner liner 210 , which is sleeved on the outside of the cylindrical section 1 of the heat exchanger 100 , and an outer liner 220 is sleeved on the outside of the inner liner 210 ; the insulation component 230 is arranged between the inner liner 210 and the outer liner 220 to support the inner liner 210 .

[0093] In the embodiment of the present invention, the heat shield 200 may be constructed of double-layer components, so as to improve the heat preservation performance of the heat shield 200 .

[0094] Specifically, if Figure 4 and Figure 5 As shown, the inner liner 210 is the inner component of the heat shield, and the outer liner 220 is the outer component of the heat shield. The inner liner is mounted outside the cylindrical section 1 of the heat exchanger 100, and the outer liner is mounted outside the inner liner. The insulation member 230 is connected between the inner and outer liner to support the inner liner.

[0095] Specifically, the insulation part 230 is arranged relative to the second outer wall 22 of the tip section 2, so that the insulation part 230 insulates the heat exchanger 100. The tip section 2 is placed close to the crystallization interface, which can reduce the impact of the tip section 2 on the temperature of the solid-liquid interface outside the crystallization area and improve the temperature stability of the solid-liquid interface.

[0096] Specifically, the heat-insulating member 230 may be a soft felt structure, which cooperates with the supporting cover to provide support for the inner liner.

[0097] Specifically, the thermal insulation component 230 can be a solid felt ring, which can not only provide thermal insulation, but also have a certain supporting strength, so that the thermal insulation component 230 can support the inner liner, and the supporting cover can be eliminated. The thermal insulation component 230 can be thickened to enhance the thermal insulation performance and prevent the thermal insulation component 230 from powdering and falling off.

[0098] Optionally, the end of the tip section 2 of the heat exchanger 100 away from the cylindrical section 1 can extend out or be flush with the bottom end surface of the heat shield 200, so that the heat exchanger 100 can be closer to the solid-liquid interface, further improving the longitudinal temperature gradient of the crystal, thereby increasing the growth rate of the crystal.

[0099] Furthermore, a third absorption coating may be applied to the end of the tip segment 2 away from the cylindrical segment 1 to reflect the distance imaging from the solid-liquid interface to the tip segment 2 for CCD field of view capture.

[0100] Optionally, during the installation of the heat exchange device, the heat shield 200 can be installed first, and then the heat exchanger 100 can be installed. The relative position of the tip segment 2 and the heat shield 200 can be adjusted by lifting and lowering. For example, the end of the tip segment 2 away from the cylindrical segment 1 is flush with the bottom end surface of the heat shield 200, or the end of the second end of the tip segment 2 is lower than the bottom end surface of the heat shield 200, thereby further increasing the longitudinal gradient of the crystal.

[0101] Specifically, the thermal field device may further include a lifting mechanism connected to the heat exchanger 100 to perform lifting and lowering adjustment on the heat exchanger 100 to control the distance between the tip section 2 and the solid-liquid interface.

[0102] Optionally, during crystal growth, a CCD can be used to capture image information to determine the liquid-inlet distance. When the end of tip segment 2, distal from cylindrical segment 1, is retracted within heat shield 200, the CCD can capture a projection image of the bottom of heat shield 200 in the molten silicon to determine the liquid-inlet distance from the bottom of heat shield 200 to the solid-liquid interface.

[0103] When the end of the tip segment 2 away from the cylindrical segment 1 extends out of the bottom end surface of the heat shield 200, the CCD can capture the projection image of the end of the tip segment 2 away from the cylindrical segment 1 in the molten silicon liquid to obtain the liquid mouth distance from the lower end of the tip segment 2 to the solid-liquid interface.

[0104] Specifically, the CCD can collect image information through the first heat exchange channel 13 and the second heat exchange channel 23. That is, the first heat exchange channel 13 and the second heat exchange channel 23 can be used as both crystal pulling channels and field of view capture windows.

[0105] Specifically, by simulating and comparing the existing thermal field device and the thermal field device in the embodiment of the present invention, under the same process conditions, the thermal field device provided by the present invention has a larger longitudinal temperature gradient of the crystal. Figure 6A and 6B As shown, the direction of the arrow represents the direction of heat transfer, and the greater the density of the arrow, the more concentrated the heat.

[0106] The existing thermal field device and the thermal field device in the embodiment of the present invention were used to perform vertical pulling of single crystal silicon growth, as shown in Table 1. The experiment verified that the maximum pulling speed in the existing thermal field device was 1.8 mm / min, while the maximum pulling speed in the thermal field device provided by the present invention was 1.96 mm / min. Compared with the existing thermal field device, the pulling speed in the thermal field device provided by the present invention was increased by 0.16 mm / min.

[0107] Table 1:

[0108] Thermal field device type Average pulling speed (mm / min) Limit pulling speed (mm / min) Existing thermal field device 1.76 1.8 Utility model thermal field device 1.86 1.96

[0109] The thermal field device described in the embodiment of the present invention can achieve the same beneficial effects as the above-mentioned heat exchanger, and will not be described in detail here.

[0110] On the third aspect, an embodiment of the present invention further discloses a single crystal furnace, which may specifically include the above-mentioned heat exchanger 100; it may also include the above-mentioned heat shield, thermal insulation component and heat exchanger, and the heat shield 200 is mounted outside the heat exchanger 100.

[0111] The single crystal furnace described in the embodiment of the present invention can achieve the same beneficial effects as the above-mentioned heat exchanger, and will not be described in detail here.

[0112] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they are aware of the basic creative concepts. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0113] Finally, it should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or terminal device that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or terminal device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article, or terminal device that includes the element.

[0114] The heat exchanger, thermal field device and single crystal furnace provided by the present invention are introduced in detail above. Specific examples are used in this article to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method and core idea of the present invention. At the same time, for general technical personnel in this field, according to the idea of the present invention, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present invention.

Claims

1. A heat exchanger, characterized in that: It comprises a cylindrical section (1) and a tip section (2) arranged along a first direction; the cylindrical section (1) and the tip section (2) are fixedly connected; the first direction is the axial direction of the heat exchanger (100); The cylindrical section (1) comprises a first inner wall (11) and a first outer wall (12); a first heat exchange cavity (14) is formed between the first inner wall (11) and the first outer wall (12); Along the first direction, the orthographic projection of the outer peripheral surface of the tip section (2) is located inside the orthographic projection of the first outer wall (12); The distance between the first inner wall (11) and the first outer wall (12) is d1, and the distance between the outer circumference and the inner circumference of the tip section (2) is d2, where d1≥1.2d2.

2. The heat exchanger according to claim 1, characterized in that d1 is 30-45mm and d2 is 4-25mm.

3. The heat exchanger according to claim 1 or 2, characterized in that: Along the first direction, the length L of the tip section (2) is 7-40 mm.

4. The heat exchanger according to claim 1 or 2, characterized in that The tip section (2) comprises a second inner wall (21) and a second outer wall (22); a second heat exchange cavity (24) is formed between the second inner wall (21) and the second outer wall (22); the second inner wall (21) is fixedly connected to the first inner wall (11), and the second outer wall (22) is fixedly connected to the first outer wall (12).

5. The heat exchanger according to claim 4, characterized in that The distance between the second inner wall (21) and the second outer wall (22) is 3-15 mm.

6. The heat exchanger according to claim 4, characterized in that The inner circumferential surface of the second inner wall (21) is coplanar with the inner circumferential surface of the first inner wall (11).

7. The heat exchanger according to claim 4, characterized in that The second outer wall (22) includes a vertical wall (222); an end portion of the vertical wall (222) is fixedly connected to the first outer wall (12); Alternatively, the second outer wall (22) includes a vertical wall (222) and a second tapered wall (223); one end of the vertical wall (222) is fixedly connected to the first outer wall (12), and the other end is fixedly connected to the second tapered wall (223).

8. The heat exchanger according to claim 7, characterized in that The heat exchanger (100) comprises a transition section (4); the cylindrical section (1) is fixedly connected to the tip section (2) via the transition section (4); The orthographic projection of the outer wall of the transition section (4) is located inside the orthographic projection of the first outer wall (12), and the orthographic projection of the second outer wall (22) is located inside the orthographic projection of the outer wall of the transition section (4).

9. The heat exchanger according to claim 8, characterized in that The outer wall of the transition section (4) is a cone.

10. The heat exchanger according to claim 4, characterized in that The flow channel of the second heat exchange chamber (24) is not connected to the flow channel of the first heat exchange chamber (14); or, the flow channel of the second heat exchange chamber (24) is connected to the flow channel of the first heat exchange chamber (14).

11. The heat exchanger according to claim 4, characterized in that The inner surface of the first inner wall (11) is provided with a first absorption coating; the inner surface of the second inner wall (21) is provided with a second absorption coating.

12. The heat exchanger according to claim 1, characterized in that Along the first direction, the end of the tip section (2) away from one end of the cylindrical section (1) is provided with a third absorption coating, and the emissivity of the third absorption coating is greater than 0.

2.

13. A thermal field device, characterized in that: The invention comprises a heat shield (200) and the heat exchanger (100) according to any one of claims 1 to 12; the heat shield (200) is sleeved outside the heat exchanger (100).

14. The thermal field device according to claim 13, characterized in that: The heat shield (200) comprises a heat-insulating component (230) and an outer liner (220); the outer liner (220) is sleeved outside the heat exchanger (100).

15. The thermal field device according to claim 14, characterized in that: Along the first direction, the heat-insulating member (230) is arranged between the cylindrical section (1) and the outer liner (220); the heat-insulating member (230) is arranged opposite to the second outer wall (22) of the tip section (2), and the surface shape of the heat-insulating member (230) matches the outer surface shape of the second outer wall (22); Alternatively, the heat shield further comprises an inner liner (210), the inner liner (210) being sleeved outside the cylindrical section (1), and the outer liner (220) being sleeved outside the inner liner (210); the heat insulating component (230) being arranged between the inner liner (210) and the outer liner (220); and the inner liner (210) being supported on the heat insulating component (230).

16. A single crystal furnace, characterized in that: The heat exchanger (100) comprises the heat exchanger (100) according to any one of claims 1 to 12.

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