Single crystal furnace

Abstract

The utility model discloses a single crystal furnace which comprises a heat preservation cylinder, a crucible, a heating piece and a guide cylinder which are coaxially arranged, the periphery of the crucible is sleeved with the heating piece, the guide cylinder is arranged above the crucible, the periphery of the heating piece and the periphery of the guide cylinder are sleeved with the heat preservation cylinder, and the single crystal furnace further comprises a heat insulation piece, the heat insulation piece is formed by extending from the inner side wall of the heat preservation cylinder to the central shaft in the radial direction and is located on the periphery of the crucible and above the heating piece; and / or the cooling mechanism is arranged on the heat preservation cylinder and located above the heat insulation piece. According to the utility model, the temperature of the area, not covered by the silicon melt, of the inner wall of the crucible can be effectively reduced, and the service life of the crucible is prolonged.

Description

Technical Field

[0001] This utility model relates to the field of crystal preparation technology, specifically to a single crystal furnace. Background Technology

[0002] A single crystal furnace is a crystal growth device that relies on a heating system to regulate the temperature inside the crucible. This system provides the heat energy needed to melt the silicon raw material. However, during crystal growth, as the silicon solution gradually crystallizes into single-crystal silicon, the silicon liquid level continuously drops, reducing the contact area between the melt and the crucible wall. Consequently, areas of the crucible wall not covered by the molten silicon are left in a high-temperature "dry-burning" state because heat cannot be transferred to the silicon solution. Under these conditions, the crucible is susceptible to phase transitions and crystallization due to high temperatures, accelerating crucible aging and shortening its lifespan. Utility Model Content

[0003] To address at least one of the problems mentioned in the background art, this utility model provides a single crystal furnace that can effectively reduce the temperature of the area on the inner wall of the crucible not covered by the silicon melt, thereby extending the service life of the crucible.

[0004] The specific technical solution provided by this utility model is as follows:

[0005] A single crystal furnace is provided, comprising a heat-insulating cylinder, a crucible, a heating element, and a flow guide cylinder coaxially arranged, wherein the heating element is sleeved around the crucible, the flow guide cylinder is positioned above the crucible, and the heat-insulating cylinder is sleeved around the heating element and the flow guide cylinder. The single crystal furnace further includes:

[0006] A heat insulation element extends radially from the inner wall of the heat-insulating cylinder towards the central axis and is located around the crucible and above the heating element.

[0007] And / or a cooling mechanism, which is mounted on the insulation cylinder and located above the insulation component.

[0008] As a preferred embodiment of the above solution, the cooling mechanism includes a thinning section disposed on the insulation cylinder, the thickness of which is less than the thickness of other parts of the insulation cylinder.

[0009] As a preferred embodiment of the above solution, the cooling mechanism includes a liquid cooling component, which is disposed on the inner wall of the insulation cylinder or the inner wall of the thinning section.

[0010] As a preferred embodiment of the above solution, the liquid cooling component includes a body, which is annular in shape, and has a liquid cavity, an inlet and an outlet communicating with the liquid cavity.

[0011] As a preferred embodiment of the above scheme, heat dissipation fins are provided on the inner wall of the body facing the crucible, and the heat dissipation fins extend radially from the inner wall of the body towards the central axis.

[0012] As a preferred embodiment of the above solution, the heat dissipation fins are provided with heat dissipation channels communicating with the liquid cavity.

[0013] As a preferred embodiment of the above scheme, a plurality of heat dissipation fins are provided, and the plurality of heat dissipation fins are arranged parallel to each other and spaced apart along the axial direction of the crucible.

[0014] As a preferred embodiment of the above scheme, the heat dissipation fins are in the shape of a ring.

[0015] As a preferred embodiment of the above scheme, the closest distance in the radial direction between the heat insulation component and the upper sidewall of the crucible is less than the closest distance in the radial direction between the heating component and the upper sidewall of the crucible.

[0016] By means of the above technical solution, in the preparation of Czochralski single crystal silicon using the single crystal furnace of this utility model, the silicon raw material is placed in a crucible, the heating element heats the crucible, and the heat preservation cylinder can achieve the heat preservation function during preparation. By setting a heat insulation element above the heating element, when the heating element heats the lower side wall of the crucible, the heat insulation element can effectively block the direct heat radiation of the heating element to the upper side wall of the crucible, significantly reducing the temperature of the upper side wall of the crucible, thereby slowing down the aging rate of the crucible. Here, the upper side wall of the crucible refers to the area not covered by the silicon melt after the silicon solution level drops. At the same time, the setting of the heat insulation element also reduces the ineffective heat loss of the heating element to the upper space, which helps to reduce the energy consumption of the heating element and optimize the thermal efficiency of the single crystal furnace. The cooling mechanism can reduce the temperature of the upper side wall of the crucible, further extending the service life of the crucible. When the cooling mechanism is used together with the heat insulation element, the cooling mechanism is set above the heat insulation element, which further reduces the temperature of the upper side wall of the crucible, thereby further extending the service life of the crucible. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the structure of this utility model;

[0019] Figure 2 for Figure 1 A schematic diagram of a partial structure;

[0020] Figure 3 This is a cross-sectional structural diagram of the liquid cooling component of this utility model. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this utility model clearer, the technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0022] It should be noted that when an element is described as being "fixed to" another element, it can be directly on the other element, or one or more intermediate elements may exist between them. When an element is described as being "connected to" another element, it can be directly connected to the other element, or one or more intermediate elements may exist between them. The terms "vertical," "horizontal," "left," "right," "upper," "lower," "inner," "outer," and "bottom," etc., used in this specification to indicate orientation or positional relationships are based on the orientation 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, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0023] As described in the background section, a single crystal furnace is a crystal growth device. Currently, in the production of single crystal silicon in the semiconductor and solar energy industries, the Czochralski (CZ) method is widely used, and the equipment used is a CZ single crystal furnace. When using a single crystal furnace to pull single crystal silicon rods, the silicon material needs to be heated to melt and then pulled into crystal shape.

[0024] Single crystal furnaces rely on a heating system to regulate the temperature inside the crucible. This system provides the heat energy needed to melt the silicon raw material, ensuring stable growth of the silicon melt. However, during crystal growth, as the silicon solution level gradually decreases, the contact area between the melt and the crucible's vertical wall (the upper sidewall of the crucible) reduces. This restricts heat transfer paths, causing areas of the crucible's wall not covered by the silicon melt to remain in a high-temperature "dry-burning" state due to the difficulty in effectively dissipating heat through the silicon solution. In this state, the crucible is susceptible to phase transitions and crystallization due to high temperatures, accelerating crucible aging and shortening its lifespan. This invention, by incorporating heat insulation and / or cooling mechanisms, effectively reduces the temperature of the upper sidewall of the crucible above the silicon solution, effectively extending the crucible's lifespan and simultaneously optimizing the thermal efficiency of the single crystal furnace. The embodiments of this invention are explained in detail below.

[0025] In the embodiments of this utility model, "above" refers to... Figure 1 The direction of the arrow in the image.

[0026] See Figure 1 This utility model provides a single crystal furnace, comprising: a heat-insulating cylinder 8, a crucible 2, a heating element 3, and a flow guide cylinder 7 arranged coaxially, wherein the heating element 3 is sleeved around the crucible 2, the flow guide cylinder 7 is disposed above the crucible 2, and the heat-insulating cylinder 8 is sleeved around the heating element 3 and the flow guide cylinder 7. The single crystal furnace further includes:

[0027] Heat insulation component 1 extends radially from the inner wall of the heat insulation cylinder 8 towards the central axis and is located on the periphery of the crucible 2 and above the heating element 3. Heat insulation component 1 is used to block the heat from the heating element 3 from being transferred upward, thereby avoiding heat radiation to the upper side wall of the crucible 2 that rises above the heating element 3.

[0028] And / or a cooling mechanism, which is installed on the insulation cylinder 8 and located above the heat insulation member 1, is used to cool the space above the heat insulation member 1 to reduce the heat baking of the upper side wall of the crucible 2 that rises above the heat insulation member 1 and extend the life of the crucible 2.

[0029] According to some embodiments of this application, the cooling mechanism includes a thinning section 81 disposed on the insulation cylinder 8, the thickness of the thinning section 81 being less than the thickness of other parts of the insulation cylinder 8. (Refer to...) Figure 1 and Figure 2 As shown, the thinned section 81, as one segment of the insulation cylinder 8, has undergone a thickness reduction process. This weakens the insulation effect of the thinned section 81 compared to other parts, thereby reducing the overall insulation effect of this space. The thinned section 81 is located above the heat insulation component 1. During the single crystal pulling process, as the silicon solution level decreases, the crucible 2 needs to be raised to ensure a suitable liquid outlet distance (the distance between the silicon solution level and the lower opening of the guide tube). After the crucible 2 is raised, the upper sidewall of the crucible 2 rises above the heating component 3 and the heat insulation component 1, thus entering the thinned section area of ​​the insulation cylinder 8. The reduced insulation effect in this area lowers the temperature of the upper sidewall of the crucible 2, reducing the baking effect on the upper sidewall and extending the lifespan of the crucible 2.

[0030] According to other embodiments of this application, the cooling mechanism may include a liquid cooling component 4, which may be disposed on the inner wall of the insulation cylinder 8. (See also...) Figure 1 and Figure 2 The liquid cooling component 4 is located above the heat insulation component 1, allowing the temperature of the area where the liquid cooling component 4 is located to be reduced. During the single crystal pulling process, as the silicon solution level decreases, the crucible 2 needs to be raised to ensure a suitable liquid outlet distance. After the crucible is raised, the upper part of the sidewall of the crucible 2 will rise above the heating component 3 and the heat insulation component 2, thus entering the area where the liquid cooling component 4 is located. Through the cooling of the liquid cooling component 4, the temperature of the upper part of the sidewall of the crucible 2 can be reduced, the baking of the upper part of the sidewall of the crucible 2 can be reduced, thereby extending the life of the crucible 2.

[0031] According to some embodiments of this application, the cooling mechanism may simultaneously include a thinning section 81 and a liquid cooling component 4. The liquid cooling component 4 may be disposed on the inner sidewall of the thinning section 81. By simultaneously disposing of the thinning section 81 and the liquid cooling component 4, the cooling effect in the area where the thinning section 81 and the liquid cooling component 4 are located can be enhanced, thereby strengthening the cooling effect of the upper sidewall of the crucible 2 and further extending the lifespan of the crucible 2. The structure of the liquid cooling component 4 is described in detail below with reference to the accompanying drawings.

[0032] See Figures 1 to 3 The liquid cooling component 4 is used for liquid cooling heat dissipation on the upper sidewall of the crucible 2. The liquid cooling component 4 includes a body 41, which is annular around the upper sidewall of the crucible 2, and has a liquid cavity 411 inside, containing coolant. The body 41 also has an inlet 412 and an outlet 413 communicating with the liquid cavity 411. The inlet 412 and outlet 413 are located on opposite sides of the body 41, with the inlet 412 at the bottom and the outlet 413 at the top, to fully promote the flow of coolant within the liquid cavity 411. The inlet 412 allows coolant to flow into the liquid cavity 411, and the outlet 413 allows coolant to flow out of the liquid cavity 411. The inlet 412 and outlet 413 are respectively connected to... The external cooling system (not shown) is connected to the liquid cooling component 4, which together form a closed-loop cooling system. The insulation cylinder 8 is provided with a through hole 52 that communicates with the thinning section 81, and the pipe 42 is set in the through hole 52. In this embodiment, the side wall of the body 41 is made of stainless steel. The cross-section of the body 41 is an annular shape that is adapted to the outer side wall of the upper side wall of the crucible 2. The height direction of the body 41 extends along the axis of the crucible 2, and the axis of the body 41 coincides with the axis of the crucible 2.

[0033] See Figure 3 The main body 41 has multiple heat dissipation fins 43 on its sidewall facing the upper sidewall of the crucible 2. The heat dissipation fins 43 extend radially from the inner sidewall of the main body 41 towards the central axis. Each heat dissipation fin 43 has a heat dissipation channel 431 communicating with the liquid cavity 411, and the heat dissipation channel 431 contains coolant. (See also...) Figure 3In this embodiment, the heat dissipation fins 43 are formed on the annular inner sidewall of the body 41. The heat dissipation fins 43 are the protruding parts of the annular inner sidewall of the body 41 towards the central axis of the body 41, which effectively increases the heat exchange area with the upper sidewall of the crucible 2. In this embodiment, the longitudinal section of the heat dissipation fins 43 is square. In other embodiments, the longitudinal section of the heat dissipation fins 43 can also be other shapes, such as irregular polygons or wavy shapes, which can further increase the heat exchange area with the upper sidewall of the crucible 2. The heat dissipation fins 43 are annular, and the cross-section of the liquid cavity 411 is arc-shaped to adapt to the upper sidewall of the crucible 2, so that the upper sidewall of the crucible 2 can be fully liquid cooled. Multiple heat dissipation fins 43 are arranged along the axial direction of the crucible 2. The cross-sections of the heat dissipation fins 43 and the heat dissipation channel 431 are both arc-shaped to adapt to the upper sidewall of the crucible 2. In this embodiment, the cross-sections of the heat dissipation fins 43 and the heat dissipation channel 431 are both annular. In this embodiment, the heat dissipation fins 43 are arranged in parallel, with adjacent heat dissipation fins 43 spaced a certain distance apart. The inner sidewall of the heat dissipation fins 43 is annular, conforming to the outer sidewall of the upper sidewall of the crucible 2. The longitudinal section of the heat dissipation channel 431 is square, and each heat dissipation channel 431 is connected to the liquid cavity 411. The height direction of the liquid cavity 411 extends along the axis of the crucible 2. It should be noted that when the body 41 is located inside the upper sidewall of the crucible 2, the heat dissipation fins 43 are formed on the annular outer sidewall of the body 41, so as to facilitate effective heat dissipation relative to the upper sidewall of the crucible 2.

[0034] The heat insulation component 1 has an arc-shaped cross-section that conforms to the upper sidewall of the crucible 2. The closest radial distance between the heat insulation component 1 and the upper sidewall of the crucible 2 is less than the closest radial distance between the heating component 3 and the upper sidewall of the crucible 2. In this embodiment, the heat insulation component 1 is used in conjunction with the liquid cooling component 4. The heat insulation component 1 has an annular cross-section and surrounds the outer sidewall of the upper sidewall of the crucible 2, located between the liquid cooling component 4 and the heating component 3. The heat insulation component 1 is made of a high-temperature resistant material with low thermal conductivity. See [link to relevant documentation]. Figure 1 The heating element 3 of the crucible 2 includes a side heating element (such as a resistance heating element or an induction heating element). The cross-section of the side heating element is circular. The side heating element surrounds the lower side wall of the crucible 2. The center of the heat insulation element 1 and the center of the side heating element are both located on the axis of the crucible 2. The closest distance between the heat insulation element 1 and the upper side wall of the crucible 2 is less than the closest distance between the side heating element and the upper side wall of the crucible 2. That is, the inner diameter of the heat insulation element 1 is smaller than the inner diameter of the side heating element, ensuring that the heat insulation element 1 can completely cover the side heating element above it, effectively blocking the direct heat radiation of the side heating element to the upper side wall of the crucible 2.

[0035] The single crystal furnace in this embodiment also includes a crucible support structure 6, a heat insulation cover 5, and a temperature measuring system (not shown). The heat insulation cover 5 covers the heat insulation cylinder 8. The crucible support structure 6 includes a crucible base 61, a crucible support 62, and a support rod 63. The crucible base 61 is a carbon-carbon crucible base and is connected to the side and part of the bottom of the crucible 2. The crucible support 62 is connected to the bottom of the crucible 2, and the support rod 63 is connected to the bottom of the crucible support 62. In this way, the support rod 63 can provide stable support for the crucible 2. The temperature measuring system includes an optical thermometer installed outside the heat insulation cylinder 8. The optical thermometer can obtain the temperature of the silicon melt by irradiating the surface of the silicon melt. During the single crystal growth process, it is necessary to regularly monitor the furnace temperature, the state of the silicon melt, and the working status of each component, and to perform necessary maintenance and adjustments in a timely manner.

[0036] In the preparation of Czochralski single-crystal silicon using this invention's single-crystal furnace, silicon raw material is first filled into crucible 2, ensuring uniform distribution. Then, heating element 3 is activated to heat the silicon raw material until it completely melts to form a silicon melt. During this process, the furnace temperature and the state of the silicon melt must be closely monitored. After the silicon melt reaches a suitable temperature and state, the single-crystal growth process begins. At this time, it is necessary to ensure that components such as heating element 3, heat insulation element 1, and liquid cooling element 4 are all in normal working condition to maintain the temperature and heat distribution within the furnace. As the silicon solution gradually decreases, the upper sidewall of the crucible gradually protrudes, and the crucible, supported by the support structure, gradually rises above heating element 3, enters above heat insulation element 1, and enters the area where the cooling mechanism is located. Heat insulation element 1 effectively blocks the heating element... The direct thermal radiation to the upper sidewall of crucible 2 significantly reduces the temperature of the upper sidewall of crucible 2, thereby slowing down the aging rate of crucible 2. At the same time, the setting of heat insulation component 1 also reduces the ineffective heat loss of heating component 3 to the space above, which helps to reduce the energy consumption of heating component 3 and optimize the thermal efficiency of single crystal furnace. The liquid cooling component 4 and the thinning section 81 of the cooling mechanism can reduce the temperature of the upper sidewall of crucible 2 and extend the service life of crucible 2. When the cooling mechanism is used together with heat insulation component 1, the cooling mechanism is set above heat insulation component 1, which further reduces the temperature of the upper sidewall of crucible 2, thereby further extending the service life of crucible 2. When the single crystal growth reaches the preset length or quality requirement, heating is stopped and the silicon melt is allowed to cool to a suitable temperature before the single crystal silicon rod 100 is taken out.

[0037] Although preferred embodiments of the present invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the present invention.

[0038] Obviously, those skilled in the art can make various modifications and variations to this utility model without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this utility model and their equivalents, this utility model also intends to include these modifications and variations.

Claims

1. A single crystal furnace, characterized in that, include: The single crystal furnace comprises a heat-insulating cylinder (8), a crucible (2), a heating element (3), and a flow guide cylinder (7) arranged coaxially. The heating element (3) is sleeved around the crucible (2), the flow guide cylinder (7) is positioned above the crucible (2), and the heat-insulating cylinder (8) is sleeved around the heating element (3) and the flow guide cylinder (7). The single crystal furnace further includes: A heat insulation element (1) is formed by extending radially toward the central axis from the inner wall of the heat insulation cylinder (8) and located around the crucible (2) and above the heating element (3). and / or a cooling mechanism, which is disposed on the insulation cylinder (8) and located above the heat insulation member (1).

2. The single crystal furnace according to claim 1, characterized in that, The cooling mechanism includes a thinning section (81) disposed on the insulation cylinder (8), the thickness of which is less than the thickness of other parts of the insulation cylinder (8).

3. The single crystal furnace according to claim 1, characterized in that, The cooling mechanism includes a liquid cooling component (4), which is disposed on the inner wall of the insulation cylinder (8).

4. The single crystal furnace according to claim 2, characterized in that, The cooling mechanism also includes a liquid cooling component (4), which is disposed on the inner wall of the thinning section (81).

5. The single crystal furnace according to claim 3 or 4, characterized in that, The liquid cooling component (4) includes a body (41), which is annular. The body (41) has a liquid cavity (411) and an inlet (412) and an outlet (413) communicating with the liquid cavity (411).

6. The single crystal furnace according to claim 5, characterized in that, The body (41) has heat dissipation fins (43) on its inner wall facing the crucible (2), and the heat dissipation fins (43) extend radially from the inner wall of the body (41) toward the central axis.

7. The single crystal furnace according to claim 6, characterized in that, The heat dissipation fins (43) are provided with heat dissipation channels (431) that communicate with the liquid cavity (411).

8. The single crystal furnace according to claim 6, characterized in that, The heat dissipation fins (43) are provided in multiple ways, and the multiple heat dissipation fins (43) are arranged parallel to each other and spaced apart along the axial direction of the crucible (2).

9. The single crystal furnace according to claim 8, characterized in that, The heat dissipation fins (43) are in the shape of rings.

10. The single crystal furnace according to claim 1, characterized in that, The closest distance in the radial direction between the heat insulation element (1) and the upper sidewall of the crucible (2) is less than the closest distance in the radial direction between the heating element (3) and the upper sidewall of the crucible (2).

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