A single crystal furnace

Abstract

The utility model discloses a single crystal furnace, including furnace body and fixedly connected in the bottom plate of furnace body bottom, the furnace body inner wall fixedly connected with the heat preservation cylinder, the heat preservation cylinder middle position is provided with the crucible, and the crucible bottom is fixedly connected with the supporting rod, and the supporting rod vertically penetrates the bottom plate setting, be provided with the heater between the heat preservation cylinder and the crucible, and the heater bottom is fixedly connected with the connecting ring, the bottom plate bottom is provided with the lifting assembly, and the lifting assembly is used for driving the lifting of connecting ring. The utility model can be to the position of heater and adjust, realize the dynamic adjustment of hot field distribution, promote the quality of single crystal silicon.

Description

Technical Field

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

[0002] A single crystal furnace is a key piece of equipment used to produce single crystal silicon by the Czochralski method. Its working principle is to melt polycrystalline silicon raw material in a high-purity quartz crucible, then cool the molten silicon liquid to produce supercooling, and then use a single silicon crystal fixed on a seed crystal axis to slowly pull the seed crystal upward after the seed crystal and the melt are fused together, so that the crystal grows at the lower end of the seed crystal.

[0003] In existing single-crystal furnaces, the positions of the heater and crucible are relatively fixed, making it difficult to change the thermal field distribution according to the crystal growth stage, charge amount, or process requirements. At different stages of crystal growth, a fixed thermal field may lead to inaccurate temperature control, resulting in problems such as unstable growth rate and increased crystal defects. When faced with different charge amounts, it is difficult to ensure uniform heating of the melt, which may result in unmelted material at the bottom or excessively high surface temperature, reducing material utilization and production efficiency.

[0004] Therefore, a single-crystal furnace needs to be developed to address the aforementioned shortcomings. Utility Model Content

[0005] The purpose of this invention is to provide a single crystal furnace that can adjust the position of the heater to achieve dynamic adjustment of the heat field distribution 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 single crystal furnace, comprising a furnace body and a base plate fixedly connected to the bottom surface of the furnace body. A heat insulation cylinder is fixedly connected to the inner wall of the furnace body, and a crucible is disposed in the middle of the heat insulation cylinder. A support rod is fixedly connected to the bottom surface of the crucible, and the support rod is vertically inserted through the base plate. A heater is disposed between the heat insulation cylinder and the crucible, and a connecting ring is fixedly connected to the bottom surface of the heater. A lifting assembly is disposed on the bottom surface of the base plate, and the lifting assembly is used to drive the connecting ring to rise and fall.

[0008] Furthermore, a plurality of insulating sleeves are fixedly connected to the bottom surface of the connecting ring. The insulating sleeves penetrate the bottom plate and are slidably connected thereto. Electrodes are provided inside the insulating sleeves. The heater and the connecting ring are provided with mounting through holes that correspond one-to-one with and communicate with the insulating sleeves. The heater is electrically connected to the electrodes through the mounting through holes by electrode bolts.

[0009] Furthermore, the lifting assembly includes several L-shaped mounting plates, which are fixedly connected to the bottom surface of the base plate in a ring with uniform intervals. A horizontally arranged lifting plate is slidably connected to the inner wall of the L-shaped mounting plate. The bottom end of the insulating protective cylinder is fixedly connected to the lifting plate. Telescopic members are symmetrically arranged at both ends of the bottom surface of the lifting plate. The telescopic members are fixedly connected to the L-shaped mounting plates, and the telescopic ends of the telescopic members are fixedly connected to the lifting plate.

[0010] Furthermore, a furnace bottom guard plate is fixedly connected to the top surface of the bottom plate.

[0011] Furthermore, a number of sliding rods are fixedly connected at even intervals along the circumference of the top surface of the furnace bottom guard plate, and a number of sliding holes corresponding to and adapted to the sliding rods are opened through the connecting ring, and the sliding rods are slidably connected in the sliding holes.

[0012] Furthermore, the telescopic component is specifically adopted as one of an electric cylinder, a hydraulic cylinder, and a pneumatic cylinder.

[0013] Furthermore, the connecting ring is specifically made of alumina ceramic material.

[0014] Compared with the prior art, the beneficial technical effects of this utility model are as follows:

[0015] This invention utilizes a lifting assembly on the bottom surface of the base plate to drive the connecting ring of the heater to move up and down. This allows for dynamic adjustment of the thermal field distribution by changing the relative position between the heater and the crucible according to different stages of silicon melting. Moving the heater upwards reduces the surface temperature of the melt, decreases the temperature gradient at the solid-liquid interface, and reduces crystal thermal stress; moving it downwards enhances the heating intensity of the melt, promoting raw material melting and solute diffusion. This allows for adaptation to the temperature requirements of various crystal growth stages (such as crystal introduction and constant diameter growth), control of the growth rate, reduction of defects such as dislocations, and adaptation to different charge amounts and crucible sizes. It also improves raw material utilization and equipment turnover efficiency, enhances the flexibility of process debugging, and strengthens the ability to handle abnormal situations. Attached Figure Description

[0016] The present invention will be further described below with reference to the accompanying drawings.

[0017] Figure 1 This is a cross-sectional view of the single crystal furnace of this utility model;

[0018] Figure 2 for Figure 1 A magnified view of part A in the middle.

[0019] Explanation of reference numerals in the attached drawings: 1. Furnace body; 2. Bottom plate; 3. Insulation cylinder; 4. Crucible; 5. Support rod; 6. Heater; 7. Connecting ring; 8. Insulating sleeve; 9. Electrode; 10. Mounting through hole; 11. Electrode bolt; 12. L-shaped mounting plate; 13. Lifting plate; 14. Telescopic component; 15. Furnace bottom guard plate; 16. Sliding rod; 17. Sliding hole. Detailed Implementation

[0020] The core of this invention is to provide a single crystal furnace that can adjust the position of the heater to achieve dynamic adjustment of the heat field distribution and improve the quality of single crystal silicon.

[0021] 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.

[0022] 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.

[0023] In one specific embodiment of this utility model, such as Figure 1 As shown, the furnace includes a furnace body 1 and a base plate 2. The base plate 2 is fixedly connected to the bottom surface of the furnace body 1, providing stable support for the entire device. An insulation cylinder 3 is fixedly connected to the inner wall of the furnace body 1 to reduce heat loss and maintain a stable internal thermal field. A crucible 4 is placed in the middle of the insulation cylinder 3 to hold polycrystalline silicon raw materials. A support rod 5 is fixedly connected to the bottom surface of the crucible 4, vertically penetrating the base plate 2. A heater 6 is installed between the insulation cylinder 3 and the crucible 4, serving as the core heating component of the single crystal furnace, used to heat and melt the polycrystalline silicon raw materials and maintain the temperature required for crystal growth. A connecting ring 7 is fixedly connected to the bottom surface of the heater 6. A lifting assembly is installed on the bottom surface of the base plate 2. The lifting assembly drives the connecting ring 7 to move up and down, thereby moving the heater 6 up and down to achieve dynamic adjustment of the thermal field distribution.

[0024] In one specific embodiment of this utility model, such as Figure 1 and Figure 2As shown, several insulating sleeves 8 are fixedly connected to the bottom surface of the connecting ring 7. These insulating sleeves 8 penetrate the bottom plate 2 and are slidably connected to it, protecting the internal electrodes 9 from high temperatures and external environmental influences. Electrodes 9 are installed inside the insulating sleeves 8 to energize the heater 6. Simultaneously, the heater 6 and the connecting ring 7 have corresponding and communicating mounting holes 10. The heater 6 is electrically connected to the electrodes 9 through the mounting holes 10 via electrode bolts 11, ensuring stable current transmission to the heater 6.

[0025] In one specific embodiment of this utility model, such as Figure 1 and Figure 2 As shown, the lifting assembly includes several L-shaped mounting plates 12, which are fixedly connected to the bottom surface of the base plate 2 in a ring at uniform intervals, forming a stable support structure. A horizontally arranged lifting plate 13 is slidably connected to the inner wall of the L-shaped mounting plates 12, and the bottom end of the insulating sleeve 8 is fixedly connected to the lifting plate 13. Telescopic components 14 are symmetrically arranged at both ends of the bottom surface of the lifting plate 13, and are fixedly connected to the L-shaped mounting plates 12, with their telescopic ends fixedly connected to the lifting plate 13. The telescopic components 14 can be any of an electric cylinder, hydraulic cylinder, or pneumatic cylinder to achieve precise lifting control. When the telescopic components 14 extend or retract, they drive the lifting plate 13 to slide up and down along the inner wall of the L-shaped mounting plates 12, thereby driving the heater 6 to rise and fall through the insulating sleeve 8 and connecting ring 7, flexibly adjusting the heat field distribution according to the crystal growth stage, material loading, and other requirements.

[0026] Specifically, the bottom plate 2 is fixedly connected to the top surface of the furnace bottom guard plate 15. The furnace bottom guard plate 15 can be made of high temperature and corrosion resistant materials, such as high-purity graphite, which can effectively protect the bottom plate 2 from high temperature and silicon liquid erosion and extend the service life of the equipment. At the same time, the furnace bottom guard plate 15 helps to distribute the heat evenly at the bottom of the hot zone and improve the stability of the hot zone.

[0027] Specifically, a number of sliding rods 16 are fixedly connected at even intervals along the circumference of the top surface of the furnace bottom guard plate 15. A sliding hole 17, corresponding to and fitting each sliding rod 16, is provided through the connecting ring 7. The sliding rods 16 are slidably connected within the sliding hole 17. This structure guides and limits the lifting and lowering process of the connecting ring 7, ensuring the heater 6 remains stable during lifting and lowering, preventing deviation or shaking, and guaranteeing the accuracy of the thermal field adjustment.

[0028] In one specific embodiment of this utility model, the connecting ring 7 is made of alumina ceramic. Alumina ceramic has the characteristics of high temperature resistance (withstanding temperatures above 1600℃), excellent insulation performance, and strong chemical stability. It can work stably for a long time in the high-temperature and highly corrosive working environment of the single crystal furnace, preventing the connecting ring 7 from reacting chemically with other components or causing conductive short circuits, thus ensuring the safe and reliable operation of the single crystal furnace.

[0029] The working principle of this utility model is as follows: When using the single crystal furnace of this utility model, polycrystalline silicon raw material is placed in crucible 4, and heater 6 is connected to electrode 9 through electrode bolt 11 to ensure circuit continuity. According to the crystal growth process requirements of this production, heater 6 is pre-adjusted to a suitable height using the lifting assembly to set the initial thermal field distribution for raw material melting and crystal growth. Heater 6 is started to heat and melt the polycrystalline silicon raw material. At this time, if the material load is large, the position of heater 6 can be appropriately lowered so that the raw material at the bottom of crucible 4 can also be fully heated and melted; if the material load is small, heater 6 is raised to avoid excessive surface temperature. After the silicon melt is melted, the seed crystal is fused with the silicon melt, and the seed crystal is pulled up to start crystal growth. As the crystal grows continuously, the silicon melt gradually decreases. According to the crystal growth rate, temperature monitoring data, etc., the lifting plate 13 is driven by the telescopic component 14 to drive the heater 6 to adjust its height in real time. When the crystal growth rate is too fast, the height of heater 6 is lowered to increase the temperature at the bottom of the thermal field and slow down the growth rate; conversely, heater 6 is raised to accelerate the growth rate and ensure the stability and quality of crystal growth.

[0030] 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.

[0031] 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 characterized by: The furnace includes a furnace body (1) and a base plate (2) fixedly connected to the bottom surface of the furnace body (1). A heat insulation cylinder (3) is fixedly connected to the inner wall of the furnace body (1). A crucible (4) is set in the middle of the heat insulation cylinder (3). A support rod (5) is fixedly connected to the bottom surface of the crucible (4). The support rod (5) is vertically connected through the base plate (2). A heater (6) is set between the heat insulation cylinder (3) and the crucible (4). A connecting ring (7) is fixedly connected to the bottom surface of the heater (6). A lifting assembly is set on the bottom surface of the base plate (2). The lifting assembly is used to drive the connecting ring (7) to rise and fall.

2. The single crystal furnace of claim 1, wherein: The bottom surface of the connecting ring (7) is fixedly connected with a plurality of insulating sleeves (8). The insulating sleeves (8) penetrate the bottom plate (2) and are slidably connected thereto. An electrode (9) is provided inside the insulating sleeve (8). The heater (6) and the connecting ring (7) are provided with mounting through holes (10) that correspond one-to-one with and communicate with the insulating sleeves (8). The heater (6) is electrically connected to the electrode (9) through the mounting through holes (10) by an electrode bolt (11).

3. The single crystal furnace according to claim 2, characterized in that: The lifting assembly includes several L-shaped mounting plates (12), which are fixedly connected to the bottom surface of the base plate (2) in a ring with uniform intervals. A horizontally arranged lifting plate (13) is slidably connected to the inner wall of the L-shaped mounting plate (12). The bottom end of the insulating sleeve (8) is fixedly connected to the lifting plate (13). Telescopic members (14) are symmetrically arranged at both ends of the bottom surface of the lifting plate (13). The telescopic members (14) are fixedly connected to the L-shaped mounting plate (12), and the telescopic ends of the telescopic members (14) are fixedly connected to the lifting plate (13).

4. The single crystal furnace according to claim 3, characterized in that: The bottom plate (2) is fixedly connected to the top surface of the furnace bottom guard plate (15).

5. The single crystal furnace according to claim 4, characterized in that: The top surface of the furnace bottom guard plate (15) is fixedly connected with several sliding rods (16) at even intervals along its circumference. Several sliding holes (17) are opened through the connecting ring (7) and are corresponding to and adapted to the sliding rods (16). The sliding rods (16) are slidably connected in the sliding holes (17).

6. The single crystal furnace according to claim 3, characterized in that: The telescopic component (14) is specifically one of an electric cylinder, a hydraulic cylinder, and a pneumatic cylinder.

7. The single crystal furnace according to claim 1, characterized in that: The connecting ring (7) is specifically made of alumina ceramic material.

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