Thermal field structure of single crystal furnace

Abstract

The utility model discloses a single crystal furnace thermal field structure which comprises a furnace body, a heat preservation barrel fixedly connected to the inner wall of the furnace body, a bottom plate fixedly connected to the bottom end of the furnace body, a crucible arranged in the middle in the heat preservation barrel, a supporting rod fixedly connected to the bottom face of the crucible, the supporting rod penetrating through the bottom plate, and a rotary lifting assembly installed at the bottom end of the supporting rod. A mounting ring is arranged between the bottom plate and the crucible, a bearing seat is arranged in the middle of the mounting ring, the bearing seat is connected with the mounting ring through a connecting piece, and the bearing seat is fixedly connected to the outer wall of the supporting rod in a sleeving mode; a heater is fixedly installed on the top face of the installation ring, and a limiting piece for limiting rotation of the installation ring is arranged on the bottom plate. According to the utility model, the relative position of the high-temperature area at the center of the heater and the center of the crucible can be kept unchanged, the longitudinal temperature gradient is kept stable, the silicon liquid is uniformly heated, the crystal growth rate fluctuation is avoided, the defects such as dislocation and twin crystal are reduced, and the quality of monocrystalline silicon is improved.

Description

Technical Field

[0001] This utility model relates to the field of single crystal furnace technology, and in particular to a single crystal furnace thermal field structure. Background Technology

[0002] A single crystal furnace is a key piece of equipment used to produce single crystal silicon using the Czochralski method. Its working principle involves melting polycrystalline silicon in a high-purity quartz crucible, then cooling the molten silicon to create supercooling. A single silicon crystal, fixed to a seed crystal axis, is then slowly pulled upwards after fusion with the melt, allowing the crystal to grow at its lower end. The thermal field structure of the single crystal furnace is a crucial component, mainly including heaters, crucibles, and insulation materials. The heaters provide heat for melting the silicon and growing the single crystal; the crucible holds the polycrystalline silicon and the growing single crystal; and the insulation material reduces heat loss and maintains the stability of the thermal field. Through the coordinated operation of these components, a suitable temperature environment and thermal field distribution are provided for single crystal silicon growth.

[0003] In existing single-crystal furnace thermal field structures, the heater's installation position within the furnace is relatively fixed. During furnace operation, as the crystal is pulled, the melt volume gradually decreases, typically requiring a slow rise of the crucible to compensate for the drop in liquid level. In this case, because the heater's position is fixed, the relative position of the high-temperature region at the heater's center and the crucible center changes as the crucible rises. This leads to an imbalance in the longitudinal temperature gradient, uneven heating of the silicon melt, and can easily cause fluctuations in crystal growth rate, resulting in defects such as dislocations and twins, thus affecting the quality of the single-crystal silicon. Simultaneously, the heat distribution radiated from the heater to the crucible also changes, preventing effective heat absorption by the silicon melt, reducing thermal efficiency, and increasing energy consumption.

[0004] Therefore, it is necessary to develop a single-crystal furnace thermal field structure to address the aforementioned defects. Utility Model Content

[0005] The purpose of this invention is to provide a single crystal furnace thermal field structure that can keep the relative position of the high-temperature region at the center of the heater and the center of the crucible unchanged, maintain a stable longitudinal temperature gradient, ensure uniform heating of the silicon melt, avoid fluctuations in crystal growth rate, reduce the generation of defects such as dislocations and twins, and improve the quality of single crystal silicon.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0007] This utility model discloses a hot zone structure for a single crystal furnace, comprising a furnace body, an insulation barrel fixedly connected to the inner wall of the furnace body, a base plate fixedly connected to the bottom of the furnace body, a crucible disposed in the middle of the insulation barrel, a support rod fixedly connected to the bottom surface of the crucible, the support rod penetrating the base plate and having a rotating and lifting assembly installed at its bottom end, an installation ring disposed between the base plate and the crucible, a bearing seat disposed in the middle of the installation ring, the bearing seat being connected to the installation ring via a connector, and the bearing seat being fixedly sleeved on the outer wall of the support rod; a heater fixedly mounted on the top surface of the installation ring, and a limiting member for restricting the rotation of the installation ring disposed on the base plate.

[0008] Furthermore, a plurality of electrode sleeves are fixedly connected at even intervals along the circumference of the bottom surface of the mounting ring. The electrode sleeves penetrate the base plate and are slidably connected thereto. An electrode is disposed inside the electrode sleeve. A plurality of mounting through holes corresponding to and communicating with the electrode sleeves are opened through the mounting ring. The heater is connected to the electrode through the mounting through holes by electrode bolts.

[0009] Furthermore, the limiting component includes several sliding rods, which are vertically and fixedly connected at even intervals to the circumference of the top surface of the base plate. Several connecting lugs corresponding to the sliding rods are fixedly connected to the outer wall of the mounting ring. The connecting lugs are provided with sliding holes adapted to the sliding rods, and the sliding rods are slidably connected in the sliding holes.

[0010] Furthermore, the connector includes a connecting ring, which is located at the middle position of the mounting ring. The inner wall of the mounting ring and the outer wall of the connecting ring are connected by a plurality of connecting plates. The connecting ring is sleeved on the outer wall of the bearing seat, and the connecting ring is fixedly connected to the bearing seat by bolts.

[0011] Furthermore, a furnace bottom guard plate is fixedly connected to the top surface of the bottom plate.

[0012] Furthermore, the mounting ring is made of alumina ceramic material.

[0013] Compared with the prior art, the beneficial technical effects of this utility model are as follows:

[0014] This invention fixes the heater to the mounting ring. When the crucible rises via the support rod and rotating lifting assembly, the heater rises synchronously with the crucible because the relative position of the mounting ring and the crucible is fixed and the mounting ring does not rotate under the action of the limiting assembly. This ensures that the relative position of the high-temperature area at the center of the heater and the center of the crucible remains unchanged, effectively avoiding the imbalance of the longitudinal temperature gradient caused by the rise of the crucible. This ensures uniform heating of the silicon melt, thereby reducing crystal growth rate fluctuations, reducing the generation of defects such as dislocations and twins, and improving the quality of monocrystalline silicon. Attached Figure Description

[0015] The present invention will be further described below with reference to the accompanying drawings.

[0016] Figure 1 This is a cross-sectional view of the hot zone structure of the single crystal furnace of this utility model;

[0017] Figure 2 For Figure 1 A magnified view of part A in the middle;

[0018] Figure 3 This is a three-dimensional structural diagram of the heater and base plate of this utility model;

[0019] Figure 4 This is a three-dimensional structural diagram of the mounting ring and connector of this utility model.

[0020] Explanation of reference numerals in the attached drawings: 1. Furnace body; 2. Insulation container; 3. Bottom plate; 4. Crucible; 5. Support rod; 6. Mounting ring; 7. Bearing seat; 8. Heater; 9. Electrode sleeve; 10. Electrode; 11. Mounting through hole; 12. Electrode bolt; 13. Sliding rod; 14. Connecting ear plate; 15. Sliding hole; 16. Connecting ring; 17. Connecting plate; 18. Bolt; 19. Furnace bottom guard plate. Detailed Implementation

[0021] The core of this invention is to provide a single-crystal furnace thermal field structure that can keep the relative position of the high-temperature region at the center of the heater and the center of the crucible unchanged, maintain a stable longitudinal temperature gradient, ensure uniform heating of the silicon liquid, avoid fluctuations in crystal growth rate, reduce the generation of defects such as dislocations and twins, and improve the quality of single-crystal silicon.

[0022] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present utility model, and not all of them. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0023] In the description of this utility model, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0024] In one specific embodiment of this utility model, such as Figure 1 and Figure 2 As shown, the furnace includes a furnace body 1, with an insulation tank 2 fixedly connected to the inner wall of the furnace body 1 to reduce heat loss and maintain a stable thermal field. A base plate 3 is fixedly connected to the bottom of the furnace body 1 to provide support for the internal structure. A crucible 4 is placed in the middle of the insulation tank 2 to hold polycrystalline silicon raw materials and grow single-crystal silicon. A support rod 5 is fixedly connected to the bottom surface of the crucible 4, passing through the base plate 3. A rotating lifting assembly is installed at the bottom of the support rod 5 to achieve the rotation and lifting of the crucible 4 (the rotating lifting assembly is existing technology and will not be described in detail here). A mounting ring 6 is set between the base plate 3 and the crucible 4. A bearing seat 7 is located in the middle of the mounting ring 6. The bearing seat 7 is connected to the mounting ring 6 through a connector and is fixedly sleeved on the outer wall of the support rod 5. During the lifting and lowering process of the crucible driven by the support rod 5, the mounting ring 6 and the components mounted on it remain relatively stable. A heater 8 is fixedly installed on the top surface of the mounting ring 6 to provide heat for silicon melting and single-crystal growth. A limiting component is provided on the base plate 3 to restrict the rotation of the mounting ring 6 and ensure the stability of the heater 8.

[0025] In one specific embodiment of this utility model, such as Figure 2 and Figure 4 As shown, several electrode sleeves 9 are fixedly connected at even intervals along the circumference of the bottom surface of the mounting ring 6. The electrode sleeves 9 penetrate the base plate 3 and are slidably connected to it. An electrode 10 is provided inside the electrode sleeve 9. Several mounting through holes 11 corresponding to and connected to the electrode sleeves 9 are opened through the mounting ring 6. The heater 8 is connected to the electrode 10 through the mounting through holes 11 by electrode bolts 12, so as to realize the power supply heating of the heater 8.

[0026] In one specific embodiment of this utility model, such as Figure 3 and Figure 4 As shown, the limiting component consists of several sliding rods 13, which are vertically fixedly connected to the top circumference of the base plate 3 at even intervals. Several connecting lugs 14, corresponding one-to-one with the sliding rods 13, are fixedly connected to the outer wall of the mounting ring 6. The connecting lugs 14 have sliding holes 15 that fit the sliding rods 13, and the sliding rods 13 are slidably connected within the sliding holes 15. Through the cooperation of the sliding rods 13 and the sliding holes 15, the rotation of the mounting ring 6 is restricted, while allowing the mounting ring 6 to move up and down within a certain range with the crucible 4, ensuring the positional stability of the heater 8 in the thermal field and preventing uneven heat distribution due to rotation.

[0027] In one specific embodiment of this utility model, such as Figure 4As shown, the connector includes a connecting ring 16, which is positioned in the middle of the mounting ring 6. The inner wall of the mounting ring 6 and the outer wall of the connecting ring 16 are connected by several connecting plates 17, forming a stable support structure. The connecting ring 16 is sleeved on the outer wall of the bearing seat 7 and fixedly connected to the bearing seat 7 by bolts 18, ensuring a firm connection between the mounting ring 6 and the support rod 5. This ensures that the mounting ring 6 and the heater 8 remain stable during the rotation and lifting of the crucible 4, preventing displacement or shaking.

[0028] In one specific embodiment of this utility model, the bottom plate 3 is fixedly connected to the top surface of the furnace bottom guard plate 19. The furnace bottom guard plate 19 can be made of high temperature and corrosion resistant materials, such as high purity graphite, to protect the bottom plate 3 from high temperature and silicon liquid erosion, reduce heat loss, and at the same time help the heat at the bottom of the hot zone to be evenly distributed.

[0029] In one specific embodiment of this utility model, the mounting ring 6 is made of alumina ceramic. Alumina ceramic has the characteristics of high temperature resistance (withstanding temperatures above 1600℃), good insulation performance, and high chemical stability. It can maintain good physical and chemical properties in the high-temperature environment of the single crystal furnace, avoiding chemical reactions with molten silicon or other components. At the same time, its insulation properties can prevent short circuits between the electrode 10 and the mounting ring 6, ensuring the normal operation of the heater 8.

[0030] The working principle of this utility model is as follows: When using the single-crystal furnace thermal field structure, polycrystalline silicon raw material is placed in crucible 4. The heater 8 and electrode 10 are connected via electrode bolts 12. Power is turned on, and the heater 8 is activated to heat and melt the polycrystalline silicon raw material. Once the polycrystalline silicon raw material has melted into molten silicon, the seed crystal is fused with the molten silicon. The rotating lifting assembly is then activated, slowly lifting the seed crystal upwards, allowing the single-crystal silicon to grow at the lower end of the seed crystal. During crystal growth, as the molten silicon continuously crystallizes, the volume of the melt gradually decreases. The crucible 4, driven by the rotating lifting assembly, slowly rises to compensate for the drop in the liquid level. Because the mounting ring 6 is limited by the sliding rod 13 and the sliding hole 15, and is connected to the bearing seat 7 and the support rod 5, the heater 8 can rise synchronously with the crucible 4, always keeping the relative position between the high temperature area in the center of the heater 8 and the center of the crucible 4 unchanged, maintaining a stable longitudinal temperature gradient, ensuring uniform heating of the silicon liquid, avoiding fluctuations in crystal growth rate, and reducing defects such as dislocations and twins; at the same time, the stable relative position also ensures that the heat radiated from the heater 8 to the crucible 4 is stable, improving heat utilization and reducing energy consumption.

[0031] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0032] The embodiments described above are merely preferred embodiments of the present utility model and are not intended to limit the scope of the present utility model. Various modifications and improvements made to the technical solutions of the present utility model by those skilled in the art without departing from the spirit of the present utility model should fall within the protection scope defined by the claims of the present utility model.

Claims

1. A single-crystal furnace thermal field structure, characterized in that: The furnace includes a furnace body (1), an insulation barrel (2) is fixedly connected to the inner wall of the furnace body (1), a base plate (3) is fixedly connected to the bottom end of the furnace body (1), a crucible (4) is arranged in the middle of the insulation barrel (2), a support rod (5) is fixedly connected to the bottom surface of the crucible (4), the support rod (5) passes through the base plate (3) and a rotating lifting component is installed at the bottom end, an installation ring (6) is arranged between the base plate (3) and the crucible (4), a bearing seat (7) is arranged in the middle of the installation ring (6), the bearing seat (7) is connected to the installation ring (6) through a connector, and the bearing seat (7) is fixedly sleeved on the outer wall of the support rod (5); a heater (8) is fixedly installed on the top surface of the installation ring (6), and a limiting component is provided on the base plate (3) to restrict the rotation of the installation ring (6).

2. The single crystal furnace thermal field structure according to claim 1, characterized in that: The mounting ring (6) has several electrode sleeves (9) fixedly connected at even intervals along its circumference on its bottom surface. The electrode sleeves (9) penetrate the base plate (3) and are slidably connected to it. An electrode (10) is provided inside the electrode sleeve (9). Several mounting through holes (11) corresponding to and connected to the electrode sleeves (9) are opened through the mounting ring (6). The heater (8) is connected to the electrode (10) through the mounting through holes (11) by electrode bolts (12).

3. The single crystal furnace thermal field structure according to claim 1, characterized in that: The limiting component includes several sliding rods (13), which are vertically fixedly connected at even intervals to the circumference of the top surface of the base plate (3). Several connecting ear plates (14) corresponding to the sliding rods (13) are fixedly connected to the outer wall of the mounting ring (6). The connecting ear plates (14) are provided with sliding holes (15) adapted to the sliding rods (13), and the sliding rods (13) are slidably connected in the sliding holes (15).

4. The single crystal furnace thermal field structure according to claim 1, characterized in that: The connector includes a connecting ring (16), which is located in the middle of the mounting ring (6). The inner wall of the mounting ring (6) and the outer wall of the connecting ring (16) are connected by a plurality of connecting plates (17). The connecting ring (16) is sleeved on the outer wall of the bearing seat (7). The connecting ring (16) and the bearing seat (7) are fixedly connected by bolts (18).

5. The single crystal furnace thermal field structure according to claim 1, characterized in that: The bottom plate (3) is fixedly connected to the top surface of the furnace bottom guard plate (19).

6. The single crystal furnace thermal field structure according to claim 1, characterized in that: The mounting ring (6) is made of alumina ceramic.

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