Double-layer crucible for continuous crystal pulling
By gradually increasing the wall thickness of the inner crucible and using silicon nitride material, the problems of deformation and corrosion of double-layer crucibles were solved, extending the service life of double-layer crucibles and improving their efficiency.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- 安徽华晟新材料有限公司
- Filing Date
- 2025-05-28
- Publication Date
- 2026-04-24
AI Technical Summary
Existing double-layer crucibles used for continuous crystal pulling are prone to deformation and surface corrosion after multiple crystal pulling operations, resulting in a short service life.
A double-layer crucible structure was designed, wherein the thickness of the circumferential sidewall of the inner crucible gradually increases from top to bottom and is made of silicon nitride. An annular space is left between the outer crucible and the inner crucible. The outer circumferential sidewall of the inner crucible is vertically set, and the inner circumferential sidewall gradually tapers inward from top to bottom with an inclination angle of 10° to 30°.
It reduces the corrosion and deformation of the inner crucible cylinder, extends the service life of the double-layer crucible, and improves its efficiency.
Smart Images
Figure CN224160738U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of single-crystal silicon crystal preparation technology, and in particular to a double-layer crucible for continuous crystal pulling. Background Technology
[0002] Currently, depending on the crystal growth method, the technology for preparing monocrystalline silicon is mainly divided into two types: the floating zone melting method and the Czochralski method. Compared with the floating zone melting method, the Czochralski method has lower cost, faster growth rate, and is more suitable for pulling large-size monocrystalline silicon rods. At present, more than 90% of solar-grade monocrystalline silicon in my country is produced by the Czochralski method.
[0003] Existing Czochralski methods generally employ continuous crystal pulling technology, where silicon is added and pulled simultaneously. This typically uses a double-layered crucible. Particle silicon is added to the outer crucible, while the single-crystal silicon is stretched within the inner crucible, thus achieving continuous stretching. However, long-term use has revealed that existing double-layered crucibles used for continuous crystal pulling are prone to deformation after repeated crystal pulling operations, and corrosion of the crucible surface occurs after prolonged use. Utility Model Content
[0004] The purpose of this application is to provide a double-layer crucible for continuous crystal pulling, so as to solve the technical problems that existing double-layer crucibles for continuous crystal pulling are prone to deformation after repeated crystal pulling and their surfaces are easily corroded.
[0005] This application provides a double-layer crucible for continuous crystal pulling, comprising:
[0006] An outer crucible cylinder and an inner crucible cylinder fitted inside the outer crucible cylinder, with an annular space between the outer crucible cylinder and the inner crucible cylinder, and the openings of the outer crucible cylinder and the inner crucible cylinder both facing upwards;
[0007] The thickness of the circumferential sidewall of the inner crucible gradually increases from top to bottom.
[0008] Furthermore, the circumferential sidewall of the inner crucible cylinder includes an outer circumferential sidewall facing the annular space and an inner circumferential sidewall facing the inner side of the inner crucible cylinder. The outer circumferential sidewall is vertically arranged, and the inner circumferential sidewall is inclined and gradually narrows inward from top to bottom.
[0009] Furthermore, the tilt angle is 10° to 30°.
[0010] Furthermore, the inner circumferential sidewall of the circumferential sidewall is inclined along the same inclination angle.
[0011] Furthermore, the upper part of the inner circumferential sidewall of the circumferential sidewall is inclined along a first inclination angle, and the middle and lower part of the inner circumferential sidewall is inclined along a second inclination angle, wherein the second inclination angle is greater than the first inclination angle.
[0012] Furthermore, the top wall thickness of the circumferential sidewall of the inner crucible cylinder is greater than or equal to 10 mm, and the bottom wall thickness of the circumferential sidewall is less than or equal to 25 mm.
[0013] Furthermore, the thickness of the central portion of the circumferential sidewall is less than or equal to 20 mm.
[0014] Furthermore, the outer crucible tube is cylindrical; the outer peripheral sidewall of the inner crucible tube is cylindrical.
[0015] Furthermore, the central axis of the inner crucible tube coincides with the central axis of the outer crucible tube.
[0016] Furthermore, the inner crucible tube is made of silicon nitride.
[0017] Compared with the prior art, the double-layer crucible for continuous crystal pulling provided in this application includes an outer crucible cylinder and an inner crucible cylinder sleeved inside the outer crucible cylinder. The openings of both the outer and inner crucible cylinders face upwards, and an annular space is left between the outer and inner crucible cylinders. Particle silicon material can be added into the annular space, and the stretching of single-crystal silicon crystals can be achieved in the inner crucible cylinder, thereby realizing the continuous stretching of single-crystal silicon crystals. Furthermore, the wall thickness of the circumferential sidewall of the inner crucible cylinder gradually increases from top to bottom.
[0018] Because continuous crystal pulling technology involves adding silicon material while continuously stretching single-crystal silicon, the entire double-layer crucible operates continuously and remains at a high temperature for an extended period. This type of continuous crystal pulling double-layer crucible is mainly made of quartz material. This makes the inner crucible tube prone to softening and structural deformation under prolonged high-temperature conditions. At the same time, the inner crucible tube is in a high-temperature operating state for a long time, and the lower part of the inner crucible tube accumulates silicon liquid for a long time. The accumulation of silicon liquid over a long period of time makes the inner wall of the inner crucible tube (especially the lower part) prone to corrosion and deformation.
[0019] Therefore, this application sets the wall thickness of the circumferential sidewall of the inner crucible tube to gradually increase from top to bottom, that is, the wall thickness is thin at the top and thickens towards the bottom. This structure greatly reduces the corrosion of the double-layer crucible, especially its inner crucible tube, during the crystal pulling process, and greatly reduces the deformation of the double-layer crucible, especially its inner crucible tube, thus extending its service life. Attached Figure Description
[0020] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.
[0021] Figure 1 This is a side view cross-sectional schematic diagram of the double-layer crucible provided in an embodiment of this application;
[0022] Figure 2 This is a top view schematic diagram of the double-layer crucible provided in the embodiment of this application.
[0023] Figure label:
[0024] 100 - Double-layer crucible;
[0025] 10 - Outer crucible cylinder;
[0026] 20 - Inner crucible cylinder;
[0027] 21-Circumferential sidewall;
[0028] 211-Inner peripheral sidewall;
[0029] 212 - Peripheral sidewall;
[0030] 30 - Ring space. Detailed Implementation
[0031] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.
[0032] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort should fall within the scope of protection of this application.
[0033] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.
[0034] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this application is in use. They are only for the convenience of describing this application 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 on this application. In addition, the terms "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.
[0035] Furthermore, terms such as "horizontal," "vertical," and "sag" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.
[0036] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "set up," "install," "connect," and "link" 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 application based on the specific circumstances.
[0037] The following detailed description of some embodiments of this application is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.
[0038] like Figure 1 and Figure 2 As shown, this application embodiment provides a double-layer crucible for continuous crystal pulling. The double-layer crucible 100 includes an outer crucible cylinder 10 and an inner crucible cylinder 20 sleeved inside the outer crucible cylinder 10. The openings of the outer crucible cylinder 10 and the inner crucible cylinder 20 are both upward-facing, and an annular space 30 is left between the outer crucible cylinder 10 and the inner crucible cylinder 20. Particle silicon material can be added into the annular space 30 between the outer crucible cylinder 10 and the inner crucible cylinder 20 while the single-crystal silicon crystal is stretched in the inner crucible cylinder 20, thereby realizing the continuous stretching of the single-crystal silicon crystal.
[0039] Furthermore, it is preferable that the wall thickness of the circumferential sidewall 21 of the aforementioned inner crucible cylinder 20 gradually increases from top to bottom.
[0040] Compared with the prior art, the double-layer crucible for continuous crystal pulling provided in this application includes an outer crucible cylinder 10 and an inner crucible cylinder 20 sleeved inside the outer crucible cylinder 10. The openings of the outer crucible cylinder 10 and the inner crucible cylinder 20 are both facing upwards, and an annular space 30 is left between the outer crucible cylinder 10 and the inner crucible cylinder 20. Particle silicon material can be added into the annular space 30, and the stretching of single-crystal silicon crystal is realized in the inner crucible cylinder 20, thereby realizing the continuous stretching of single-crystal silicon crystal. Furthermore, the wall thickness of the circumferential sidewall 21 of the inner crucible cylinder 20 gradually increases from top to bottom.
[0041] Since continuous crystal pulling technology involves adding silicon material while continuously stretching single-crystal silicon, the entire double-layer crucible 100 operates continuously and remains at a high temperature for a long time. This type of continuous crystal pulling double-layer crucible is mainly made of quartz material, which makes the inner crucible cylinder 20 prone to softening and structural deformation under high temperature conditions for a long time. At the same time, the inner crucible cylinder 20 is in a high-temperature operating state for a long time, and the lower part of it accumulates silicon liquid for a long time. The accumulation of silicon liquid for a long time makes the inner wall of the inner crucible cylinder 20 (especially the lower part) prone to corrosion and deformation.
[0042] Based on this, the embodiments of this application set the wall thickness of the circumferential sidewall 21 of the aforementioned inner crucible cylinder 20 to gradually increase from top to bottom, that is, the wall thickness is thin at the top and thickens towards the bottom. This structure greatly reduces the corrosion degree of the double-layer crucible 100, especially its inner crucible cylinder 20, during the crystal pulling process, and greatly reduces the deformation of the double-layer crucible 100, especially its inner crucible cylinder 20, thus extending its service life.
[0043] One specific embodiment is, as follows: Figure 1 As shown, the circumferential sidewall 21 of the aforementioned inner crucible cylinder 20 may specifically include an outer circumferential sidewall 212 facing the aforementioned annular space 30 and an inner circumferential sidewall 211 facing the inner side of the aforementioned inner crucible cylinder 20.
[0044] Preferably, the aforementioned outer peripheral sidewall 212 can be vertically arranged, and the aforementioned inner peripheral sidewall 211 can be gradually tapered inward and inclined from top to bottom; more preferably, the sidewall of the aforementioned outer crucible cylinder 10 can be vertically arranged.
[0045] This configuration achieves the structural feature that the wall thickness of the circumferential sidewall 21 of the inner crucible cylinder 20 gradually increases from top to bottom, while also ensuring that the outer circumferential sidewall 212 of the inner crucible cylinder 20 and the sidewall of the outer crucible cylinder 10 are both vertically arranged, making their walls parallel to each other and more convenient to use. At the same time, the annular space 30 formed between the two walls makes it easier to add silicon material.
[0046] Furthermore, it is preferable that the aforementioned outer crucible tube 10 is cylindrical, specifically a vertically arranged cylindrical shape, and the outer peripheral sidewall 212 of the aforementioned inner crucible tube 20 is also cylindrical, specifically a vertically arranged cylindrical shape, to further facilitate use.
[0047] Based on the aforementioned embodiments, more preferably, the central axis of the inner crucible cylinder 20 coincides with the central axis of the outer crucible cylinder 10. This not only ensures that the annular space 30 is uniformly arranged along the circumferential space, facilitating and making it convenient to add materials, but also that the double-layer crucible 100 is symmetrically arranged along the central axis, facilitating continuous crystal pulling.
[0048] Furthermore, it is specifically preferred that the inclination angle of the inner circumferential sidewall 211 of the aforementioned inner crucible cylinder 20 is 10° to 30°, and this inclination angle is the inclination angle between the inner circumferential sidewall 211 and the vertically arranged outer circumferential sidewall 212.
[0049] The aforementioned structure, with a thinner top wall and a thicker wall towards the bottom of the inner crucible cylinder 20, significantly reduces corrosion and deformation during the crystal pulling process, thereby extending the overall service life of the double-layer crucible 100 and improving its efficiency. The specific tilt angle can be determined based on the size of the double-layer crucible 100 and the continuous tensile strength of the single-crystal silicon crystal.
[0050] Based on this, one possible embodiment is, as follows: Figure 1 As shown, the inner circumferential sidewall 211 of the aforementioned inner crucible cylinder 20 can be inclined along the same aforementioned tilt angle. This allows the entire surface of the inner circumferential sidewall 211 of the inner crucible cylinder 20 to be flat and inclined along the same tilt angle, which not only facilitates direct manufacturing and molding, but also better ensures the technical requirement of thin top thickness and thick bottom thickness.
[0051] Another optional embodiment is that the upper part of the aforementioned inner peripheral sidewall 211 can be inclined at a first inclination angle, and the middle and lower part of the inner peripheral sidewall 211 can be inclined at a second inclination angle, and the second inclination angle is greater than the first inclination angle, so that the upper part of the inner peripheral sidewall 211 is still relatively thin and the inclination change is relatively small, while the middle and lower part of the inner peripheral sidewall 211 begins to have a relatively large inclination change and the overall wall thickness is relatively thick. Since the lower part of the inner crucible cylinder 20 has a lot of silicon liquid accumulated, it is easy to corrode and more prone to deformation. Therefore, the middle and lower part of the inner crucible cylinder 20 needs to be thicker than its upper part, while the upper part can be relatively thinner. At the same time, it can further save the material for making the crucible. Therefore, the inner peripheral sidewall 211 can be segmented and set into a structure with different inclination angles as needed.
[0052] In one optional embodiment, the wall thickness of the top of the circumferential sidewall 21 of the aforementioned inner crucible cylinder 20 (i.e., the minimum wall thickness position) should be at least greater than or equal to 10 mm. Even if materials are saved, the basic crucible usage requirements must be guaranteed. Furthermore, the wall thickness of the bottom of the circumferential sidewall 21 of the aforementioned inner crucible cylinder 20 (i.e., the maximum wall thickness position) should preferably not exceed 25 mm, that is, less than or equal to 25 mm. While ensuring the bottom's corrosion resistance and deformation resistance are maximized, the wall thickness should not be too thick, as excessive thickness will also affect its use.
[0053] Furthermore, since the inner crucible cylinder 20 has a lot of molten silicon accumulating below the middle, it is prone to corrosion and deformation. Therefore, the wall thickness of the middle part of the circumferential sidewall 21 of the inner crucible cylinder 20 should preferably be less than or equal to 20 mm to enhance the corrosion resistance and deformation resistance of this position.
[0054] Furthermore, since the molten silicon mostly accumulates in the inner crucible cylinder 20 of the double-layer crucible 100, and since silicon nitride material has the material properties of high temperature resistance, high strength, corrosion resistance and high insulation, preferably, the inner crucible cylinder 20 of the double-layer crucible for continuous crystal pulling in this embodiment of the application can be made of silicon nitride material to replace the quartz sand material mostly used in conventional crucibles. This not only reduces the amount of quartz sand required to manufacture the crucible, but also further improves the high temperature resistance and corrosion resistance of the inner crucible cylinder 20, improves its structural strength, and can further extend its service life.
[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.
Claims
1. A double-layer crucible for continuous crystal pulling, characterized in that, include: An outer crucible cylinder and an inner crucible cylinder fitted inside the outer crucible cylinder, with an annular space between the outer crucible cylinder and the inner crucible cylinder, and the openings of the outer crucible cylinder and the inner crucible cylinder both facing upwards; The thickness of the circumferential sidewall of the inner crucible gradually increases from top to bottom.
2. The double-layer crucible for continuous crystal pulling according to claim 1, characterized in that, The circumferential sidewall of the inner crucible cylinder includes an outer circumferential sidewall facing the annular space and an inner circumferential sidewall facing the inner side of the inner crucible cylinder. The outer circumferential sidewall is vertically arranged, and the inner circumferential sidewall is inclined and gradually narrows inward from top to bottom.
3. The double-layer crucible for continuous crystal pulling according to claim 2, characterized in that, The tilt angle is 10° to 30°.
4. The double-layer crucible for continuous crystal pulling according to claim 2 or 3, characterized in that, The inner circumferential sidewall of the circumferential sidewall is inclined along the same inclined angle.
5. The double-layer crucible for continuous crystal pulling according to claim 2 or 3, characterized in that, The upper part of the inner circumferential sidewall of the circumferential sidewall is inclined along a first inclination angle, and the lower middle part of the inner circumferential sidewall is inclined along a second inclination angle, wherein the second inclination angle is greater than the first inclination angle.
6. The double-layer crucible for continuous crystal pulling according to claim 2, characterized in that, The top wall thickness of the circumferential sidewall of the inner crucible cylinder is greater than or equal to 10 mm, and the bottom wall thickness of the circumferential sidewall is less than or equal to 25 mm.
7. The double-layer crucible for continuous crystal pulling according to claim 6, characterized in that, The thickness of the middle part of the circumferential sidewall is less than or equal to 20 mm.
8. The double-layer crucible for continuous crystal pulling according to claim 2, characterized in that, The outer crucible tube is cylindrical; the outer peripheral sidewall of the inner crucible tube is cylindrical.
9. The double-layer crucible for continuous crystal pulling according to claim 8, characterized in that, The central axis of the inner crucible tube coincides with the central axis of the outer crucible tube.
10. The double-layer crucible for continuous crystal pulling according to claim 1, characterized in that, The inner crucible cylinder is made of silicon nitride.