Auxiliary furnace chamber and single crystal furnace
By setting up multiple insulation rings and air inlets in the single-crystal furnace sub-furnace chamber, the problem of slow cooling speed and many defects of the crystalline silicon rod is solved, and more efficient heat dissipation and quality improvement is achieved.
Patent Information
- Application Number
- CN202420143389.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-01-19
- Publication Date
- 2024-12-27
- Estimated Expiration
- 2034-01-19
AI Technical Summary
The dislocation problem caused by the brittle transformation of crystalline silicon rods in the secondary chamber of traditional single-crystal furnaces results in poor quality of single-crystal silicon rods and slow cooling rate affects yield.
Multiple insulation rings and air inlets are provided on the inner wall of the sub-furnace chamber. The insulation ring is welded and fixed with the inner wall of the sub-furnace chamber. The air inlet is located in the partition area formed by the insulation ring and is used to connect the external argon gas source to shorten the single The cooling time of the crystalline silicon rod in a specific temperature zone.
By accelerating the heat dissipation speed of the single crystal silicon rod, reducing the occurrence of defects during temperature changes, and improving the quality and production efficiency of the single crystal silicon rod.
Smart Images
Figure CN222251104U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of crystalline silicon preparation devices, and more specifically, to an auxiliary furnace chamber and a single crystal furnace. Background Art
[0002] In the field of semiconductor silicon wafer manufacturing, the traditional vertical pulling single crystal furnace is equipped with an auxiliary furnace chamber above the main furnace body. After the crystal is pulled out of the melt in the single crystal furnace, it rises to the auxiliary furnace chamber for slow cooling. The current single crystal furnace auxiliary furnace chamber is mainly a stainless steel inner wall layer with a smooth inner wall surface, circulating water flowing in the interlayer, and argon gas flowing into the top of the auxiliary furnace chamber; the crystal rod rises into the auxiliary chamber and is mainly cooled by radiation and argon convection. The cooling rate is slow, and the crystal rod spends the same time in each temperature zone, resulting in a large number of micro defects in the crystal rod when the temperature changes, which in turn affects the quality of the produced single crystal silicon rod.
[0003] Therefore, how to overcome the above problems has become one of the technical problems that need to be solved urgently at this stage. Utility Model Content
[0004] In view of this, the utility model provides an auxiliary furnace chamber and a single crystal furnace, which shortens the time for the single crystal silicon rod to reach the heat dissipation temperature zone (530℃-550℃) and reduces the dislocation problem caused by the brittle-ductile transition of the single crystal silicon rod when the temperature changes.
[0005] In a first aspect, the present application provides an auxiliary furnace chamber, comprising a plurality of heat-insulating rings, wherein the heat-insulating rings are fixed to the inner wall of the auxiliary furnace chamber, and the plane where the heat-insulating rings are located is parallel to the cross section of the auxiliary furnace chamber;
[0006] A plurality of air inlets are provided, wherein the air inlets are located in the partitioning interval formed by the heat insulating ring, and the air inlets are used for connecting to an external argon gas source.
[0007] Optionally, the insulation ring comprises an inner diameter and an outer diameter, the outer diameter of the insulation ring is equal to the inner diameter of the auxiliary furnace chamber, and the inner diameter range of the insulation ring is 300-400mm.
[0008] Optionally, the insulation rings are arranged at intervals within a range of 5 meters upward along the bottom of the auxiliary furnace chamber; wherein, one of the insulation rings is fixed to the bottom of the inner wall of the auxiliary furnace chamber.
[0009] Optionally, the distance between two adjacent insulation rings close to the bottom of the auxiliary furnace chamber is smaller than the distance between two adjacent insulation rings far from the bottom of the auxiliary furnace chamber.
[0010] Optionally, the insulation ring is connected to the inner wall of the auxiliary furnace chamber by welding.
[0011] Optionally, the thermal insulation ring is made of stainless steel.
[0012] Optionally, the air inlet is located within 3 meters above the bottom of the auxiliary furnace chamber.
[0013] Optionally, one air inlet is provided on the auxiliary furnace chamber wall between every two adjacent insulation rings.
[0014] Optionally, the thickness of the thermal insulation ring ranges from 1 to 2 cm.
[0015] In a second aspect, the present application provides a single crystal furnace, comprising a main furnace chamber and an auxiliary furnace chamber as described above that is connected to the main furnace chamber.
[0016] Compared with the prior art, the auxiliary furnace chamber and the single crystal furnace provided by the utility model achieve at least the following beneficial effects:
[0017] 1. Add a heat insulation ring at a specific height of the auxiliary furnace chamber to reduce the heat radiation of the high-temperature liquid surface in the single crystal furnace to the single crystal silicon rod, speed up the heat dissipation, increase the crystal rod pulling speed, and increase the output;
[0018] 2. Add an argon gas inlet in the area separated by the insulation ring to speed up the cooling rate of the single crystal silicon rod that reaches the specific temperature zone at this time, shorten the time that the single crystal silicon rod is in the temperature range of 530℃-550℃, inhibit the generation of defects, and improve the quality of the single crystal silicon rod.
[0019] Of course, any product implementing the present utility model does not necessarily need to achieve all of the above-mentioned technical effects at the same time.
[0020] Other features and advantages of the present invention will become apparent from the following detailed description of exemplary embodiments of the present invention with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the present invention and, together with the description, serve to explain the principles of the present invention.
[0022] Figure 1 The figure shows a schematic diagram of the longitudinal cross-section structure of the auxiliary furnace chamber in the embodiment of the utility model;
[0023] Figure 2 Shown is a top view of the heat insulation ring in an embodiment of the present utility model. DETAILED DESCRIPTION
[0024] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that unless otherwise specifically stated, the relative arrangements of components and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention.
[0025] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the present invention, its application, or uses.
[0026] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered as part of the specification.
[0027] In all examples shown and discussed herein, any specific values should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.
[0028] It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further discussed in the subsequent drawings. Detailed description will be given below in conjunction with the drawings and specific embodiments.
[0029] Figure 1 The figure shows a schematic diagram of the longitudinal section structure of the auxiliary furnace chamber in the embodiment of the utility model. Figure 2 The figure shows a top view of the heat insulation ring in the embodiment of the utility model, please refer to Figure 1 and Figure 2 The utility model embodiment provides a secondary furnace chamber 1, comprising:
[0030] A plurality of heat-insulating rings 2, the heat-insulating rings 2 are fixed to the inner wall of the auxiliary furnace chamber 1, and the plane where the heat-insulating rings 2 are located is parallel to the cross section of the auxiliary furnace chamber 1;
[0031] A plurality of air inlets 3 are provided, wherein the air inlets 3 are located in a partitioning area 20 formed by the heat insulating ring 2, and the air inlets 3 are used for connecting to an external argon gas source.
[0032] Specifically, an auxiliary furnace chamber 1 provided by an embodiment of the utility model is located directly above the main furnace chamber of the CZ single crystal furnace. In a direction parallel to the cross section of the auxiliary furnace chamber 1, that is, along the radial direction of the auxiliary furnace chamber 1, a plurality of thermal insulation rings 2 are fixed to the inner wall of the auxiliary furnace chamber 1, and a partition section 20 is formed between the thermal insulation rings 2 and a plurality of partition sections 20 are formed between the plurality of thermal insulation rings 2. There are more than one air inlet 3 on the partition section 20, and the air inlet 3 is used to connect an external argon gas source. In this way, by arranging a plurality of thermal insulation rings 2 and arranging a plurality of air inlets 3 in the partition section 20 formed by the thermal insulation rings 2, the plurality of thermal insulation rings 2 form a physical partition. The heat radiation of the silicon melt in the main furnace chamber of the single crystal furnace to the auxiliary furnace chamber 1 is reduced. In the process of pulling the single crystal silicon rod 10 from the single crystal furnace to the auxiliary furnace chamber 1, as the temperature rises, the single crystal silicon rod 10 gradually cools down. By arranging a plurality of air inlets 3 in the partition interval 20, the cooling rate of the single crystal silicon rod 10 after entering the auxiliary furnace chamber 1 can be effectively improved, the cooling time of the single crystal silicon rod 10 at a specific temperature can be shortened, the dislocation caused by the brittle-ductile transition of the single crystal silicon rod 10 in the temperature change zone can be reduced, the quality of the single crystal silicon rod 10 can be improved, the turnover time of the single crystal silicon rod 10 can be saved, the speed of pulling the single crystal silicon rod 10 can be increased, and the production efficiency of the single crystal silicon rod 10 can be improved.
[0033] It should be noted that the auxiliary furnace chamber 1 can be an auxiliary furnace chamber 1 of a Czochralski single crystal furnace, that is, the auxiliary furnace chamber 1 can be applied to the relevant field of preparing single crystal silicon rods 10 by Czochralski method. Figure 1 The number of thermal insulation rings 2 in the auxiliary furnace chamber 1 is for illustration only (only 2 are shown), and does not limit the number of thermal insulation rings 2 actually contained in the auxiliary furnace chamber 1. In some other embodiments, the number of thermal insulation rings 2 may also be selected to be greater than or equal to 3. For example, the number of thermal insulation rings 2 is 3. Further, in one embodiment of the present application, the number of thermal insulation rings 2 is 5. Further, in one embodiment of the present application, the number of thermal insulation rings 2 is 7. They are not listed one by one here. In actual applications, the number of thermal insulation rings 2 can be determined according to actual needs.
[0034] In an optional embodiment provided by the present utility model, please refer to Figure 1 and Figure 2 The insulation ring 2 includes an insulation ring inner diameter r2 and an insulation ring outer diameter R2. The insulation ring outer diameter R2 is equal to the auxiliary furnace chamber inner diameter r1. The insulation ring inner diameter r2 ranges from 300 to 400 mm.
[0035] Specifically, the thermal insulation ring 2 is a circular ring structure, including an inner diameter r2 of the thermal insulation ring and an outer diameter R2 of the thermal insulation ring. Since the thermal insulation ring 2 is fixed on the inner wall of the auxiliary furnace chamber 1, the outer diameter R2 of the thermal insulation ring is equal to the inner diameter r1 of the auxiliary furnace chamber, thereby ensuring that the thermal insulation ring 2 is fixed on the inner wall of the auxiliary furnace chamber 1 and will not loosen. The current common inner diameter r1 of the auxiliary furnace chamber is 410 mm, and the diameter of the single crystal silicon rod 10 is between 253 and 263 mm. In the embodiment of the utility model, the inner diameter r2 of the thermal insulation ring is between 300 and 400 mm, which can prevent the thermal insulation ring 2 from contacting with the single crystal silicon rod 10 and contaminating the single crystal silicon rod 10 while achieving a partition effect. In this way, the thermal insulation ring 2 is set to a circular ring structure, which has a simple process and is convenient for mass production. By limiting the range of the inner and outer diameters of the thermal insulation ring 2, the thermal insulation ring 2 can be prevented from loosening from the inner wall of the auxiliary furnace chamber 1, and a certain gap can be maintained with the single crystal silicon rod 10 while achieving a partition effect to prevent the single crystal silicon rod 10 from being squeezed or damaged. Optionally, the inner diameter r2 of the heat insulation ring is 320-380 mm, or 350-390 mm, or 330-370 mm. Optionally, the inner diameter r2 of the heat insulation ring is one of 310 mm, 320 mm, 340 mm, 370 mm, etc.
[0036] In an optional embodiment provided by the present utility model, continue to refer to Figure 1 and Figure 2 The insulation rings 2 are arranged at intervals within a range of 5 meters upward from the bottom of the auxiliary furnace chamber 1; wherein, a insulation ring 2 is fixed to the bottom of the inner wall of the auxiliary furnace chamber 1.
[0037] Specifically, the height of the currently commonly used auxiliary furnace chamber 1 is 6 meters, and the insulation rings 2 are arranged at intervals in the interval of 5 meters from the bottom of the auxiliary furnace chamber 1. For example, the interval setting can be uniform or irregular. Of course, the specific spacing distance of the insulation rings 2 can be flexibly adjusted according to actual production needs, and the present application does not limit it here. That is, multiple insulation rings 2 are arranged at intervals in the auxiliary furnace chamber 1 to form multiple partition intervals 20, and the spacing of multiple partition intervals 20 can be adjusted according to actual production needs; preferably, the insulation rings 2 can be set to irregular spacing to meet the need for accelerated cooling in a certain temperature range. It can be understood that an insulation ring 2 is fixed to one end of the bottom of the inner wall of the auxiliary furnace chamber 1 close to the main furnace chamber of the single crystal furnace to reduce the heat radiation of the silicon melt in the main furnace chamber of the single crystal furnace to the auxiliary furnace chamber 1, thereby reducing the heat radiation of the silicon melt in the main furnace chamber of the single crystal furnace to the single crystal silicon rod 10. In this way, by arranging the insulation rings 2 at intervals in the area 5 meters upward from the bottom of the auxiliary furnace chamber 1, multiple insulation rings 2 can also form multiple partition sections 20, which can form multiple barriers to the liquid level of the single crystal furnace.
[0038] In some embodiments, the thermal insulation rings 2 are spaced apart within a distance range of 5 meters upward from the bottom of the auxiliary furnace chamber 1; further, in some embodiments, the thermal insulation rings 2 are spaced apart within a distance range of 4 meters upward from the bottom of the auxiliary furnace chamber 1; further, in some embodiments, the thermal insulation rings 2 are spaced apart within a distance range from 1 meter from the bottom of the auxiliary furnace chamber 1 to 5 meters from the bottom of the auxiliary furnace chamber 1; by adjusting and optimizing the setting range of the thermal insulation rings 2, the partition interval 20 can be further increased to enhance the thermal insulation effect.
[0039] In an optional embodiment provided by the present utility model, please continue to refer to Figure 1 and Figure 2 The distance between two adjacent insulation rings 2 close to the bottom of the auxiliary furnace chamber 1 is smaller than the distance between two adjacent insulation rings 2 far from the bottom of the auxiliary furnace chamber 1 .
[0040] Specifically, the thermal insulation rings 2 are arranged at intervals within a range of 5 meters upwards from the bottom of the auxiliary furnace chamber 1, wherein the spacing between two adjacent thermal insulation rings 2 near one end of the bottom of the auxiliary furnace chamber 1 is smaller than the spacing between two adjacent thermal insulation rings 2 far from one end of the bottom of the auxiliary furnace chamber 1, that is, at one end of the auxiliary furnace chamber 1 close to the main furnace chamber of the single crystal furnace, the spacing between two adjacent thermal insulation rings 2 is smaller; and at one end of the auxiliary furnace chamber 1 far from the main furnace chamber of the single crystal furnace, the spacing between two adjacent thermal insulation rings 2 is larger; wherein, along the direction from one end of the auxiliary furnace chamber 1 close to the main furnace chamber of the single crystal furnace to the end of the auxiliary furnace chamber 1 far from the main furnace chamber of the single crystal furnace, the spacing between two adjacent thermal insulation rings 2 can be gradually increased in sequence, or, along the direction from one end of the auxiliary furnace chamber 1 close to the main furnace chamber of the single crystal furnace to the auxiliary furnace In the direction of the middle position of the auxiliary furnace chamber 1, the distance between two adjacent thermal insulation rings 2 gradually increases, and in the direction along the middle of the auxiliary furnace chamber 1 pointing to the end of the auxiliary furnace chamber 1 away from the main furnace chamber of the single crystal furnace, the distance between two adjacent thermal insulation rings 2 remains unchanged at a fixed interval; or, in the direction along the end of the auxiliary furnace chamber 1 close to the main furnace chamber of the single crystal furnace pointing to the middle position of the auxiliary furnace chamber 1, the distance between two adjacent thermal insulation rings 2 gradually increases, and in the direction along the middle of the auxiliary furnace chamber 1 pointing to the end of the auxiliary furnace chamber 1 away from the main furnace chamber of the single crystal furnace, the distance between two adjacent thermal insulation rings 2 gradually decreases, but it is still larger than the distance between two adjacent thermal insulation rings 2 in the direction along the end of the auxiliary furnace chamber 1 close to the main furnace chamber of the single crystal furnace pointing to the middle position of the auxiliary furnace chamber 1. In this way, the distance between two adjacent insulation rings 2 near the bottom of the auxiliary furnace chamber 1 is set to be smaller than the distance between two adjacent insulation rings 2 far from the bottom of the auxiliary furnace chamber 1, which can better block the heat radiation of the silicon melt in the main furnace chamber of the single crystal furnace to the bottom of the single crystal silicon rod 10, accelerate the cooling rate of the single crystal silicon rod 10 in a specific temperature zone, and reduce the number of defects.
[0041] In an optional embodiment provided by the present utility model, continue to refer to Figure 1 The heat insulation ring 2 is connected to the inner wall of the auxiliary furnace chamber 1 by welding.
[0042] Specifically, during the crystal pulling process, the polysilicon raw material is first melted in the main furnace chamber of the single crystal furnace. When the temperature of the silicon melt is stable, the seed crystal is immersed in the silicon melt to start seeding. After the seeding is completed, the shoulder is released, and the crystal diameter gradually increases to a preset width and then grows in equal diameter. The single crystal silicon body in the growing process is slowly pulled to the auxiliary furnace chamber 1 until the equal diameter growth is completed and enters the final stage. The diameter of the single crystal silicon rod 10 is gradually reduced to separate from the silicon melt. During the entire growth process of the single crystal silicon rod 10, in order to ensure that the insulation ring 2 is fixed In order to prevent the thermal insulation ring 2 from loosening on the inner wall of the auxiliary furnace chamber 1 and affecting the silicon melt and the single crystal silicon rod 10, the thermal insulation ring 2 is connected to the inner wall of the auxiliary furnace chamber 1 by welding. The welding can be carried out by heating, pressurizing or both, with or without filling materials, so that the thermal insulation ring 2 and the inner wall of the auxiliary furnace chamber 1 are connected into one by atomic bonding force, wherein welding includes gas welding, electric welding, cold welding, etc.; in this way, by welding and fixing the thermal insulation ring 2 to the auxiliary furnace chamber 1, it can be prevented from loosening and contaminating the single crystal furnace and the single crystal silicon rod 10.
[0043] Continue to refer Figure 1 and Figure 2 In an optional embodiment provided by the present utility model, the insulation ring 2 is made of stainless steel.
[0044] Specifically, the auxiliary furnace chamber 1 of the single crystal furnace for vertical pulling single crystals is mainly a stainless steel inner wall layer, and the thermal insulation ring 2 is connected to the auxiliary furnace chamber 1 by welding. The material of the thermal insulation ring 2 is the same as or similar to that of the auxiliary furnace chamber 1. Therefore, the thermal insulation ring 2 is made of stainless steel. In this way, the intermolecular force between the thermal insulation ring 2 and the auxiliary furnace chamber 1 is greater during welding, and the welding is more firm.
[0045] In an optional embodiment provided by the present utility model, continue to refer to Figure 1 The air inlet 3 is located within a range of 3 meters above the bottom of the auxiliary furnace chamber 1.
[0046] Specifically, the air inlet 3 is arranged in the area 3 meters above the bottom of the auxiliary furnace chamber 1, which is a temperature range of 530°C-550°C. In order to reduce the dislocation caused by the brittle-ductile transition of the single crystal silicon rod 10 in this temperature range, the area 3 meters above the bottom of the auxiliary furnace chamber 1 has a higher requirement for heat dissipation. Therefore, distributing the air inlet 3 in the area 3 meters above the bottom of the auxiliary furnace chamber 1 is more conducive to the heat dissipation effect of the single crystal silicon rod 10 in the temperature range of 530°C-550°C, and can make the direct-pull single crystal silicon rod 10 quickly cool down in the temperature range of 530°C-550°C after entering the auxiliary furnace chamber 1, thereby saving the turnover time of the single crystal silicon rod 10 and improving the output of the single crystal silicon rod 10.
[0047] In some embodiments, the air inlet 3 is located within a range of 3 meters above the bottom of the auxiliary furnace chamber 1; further, in some embodiments, the air inlet 3 is located within a range of 2 meters above the bottom of the auxiliary furnace chamber 1; further, in some embodiments, the air inlet 3 is located within a range of 1 meter from the bottom of the auxiliary furnace chamber 1 to 3 meters from the bottom of the auxiliary furnace chamber 1; in this way, by adjusting and optimizing the position of the air inlet 3, the cooling rate of a specific temperature zone can be flexibly controlled, and the time that the single crystal silicon rod 10 is in different temperature zones during cooling can be adjusted to achieve the effect of improving the quality of the single crystal silicon rod 10.
[0048] It should be noted that the air inlet 3 is used to introduce argon gas into the partition zone 20 formed by two adjacent insulation rings 2 in the auxiliary furnace chamber 1, so as to cool the single crystal silicon rod 10 in a specific temperature zone, and adjust the original cooling time of each temperature zone to the same time that the crystal rod is in the temperature range of 530℃-550℃ to shorten the time, so as to suppress the generation of micro defects.
[0049] In an optional embodiment provided by the present utility model, continue to refer to Figure 1 An air inlet 3 is provided on the wall of the auxiliary furnace chamber 1 between every two adjacent insulation rings 2.
[0050] Specifically, an air inlet 3 is provided on the wall of the auxiliary furnace chamber 1 between adjacent insulation rings 2, which is used to connect an external argon gas source to cool the single crystal silicon rod 10 pulled to the auxiliary furnace chamber 1. The auxiliary furnace chamber 1 cools the single crystal silicon rod 10 mainly in two ways. First, the heat radiation formed by the silicon melt in the main furnace chamber of the single crystal furnace on the single crystal silicon rod 10 is isolated by the insulation ring 2. Secondly, inert gas is introduced through the air inlet 3 between the adjacent insulation rings 2 on the inner wall of the auxiliary furnace chamber 1 to cool the single crystal silicon rod 10 pulled to the auxiliary furnace chamber 1 by air flow. It should be noted that in order to prevent the internal pressure of the auxiliary furnace chamber 1 from increasing, the argon gas introduced into the auxiliary furnace chamber 1 through the air inlet 3 is at most Finally, it is discharged through the gas outlet (not shown in the figure) at the bottom of the single crystal furnace. Because the atmosphere of the crystal pulling process requires vacuuming and then introducing inert gas to form a protective gas to prevent the polysilicon raw material from reacting with oxygen in the air to generate silicon oxide impurities, in the original crystal pulling process, an inert gas access port (not shown in the figure) is provided at the top of the auxiliary furnace chamber 1, and a gas outlet is provided at the bottom of the main furnace chamber of the single crystal furnace. In the embodiment of the utility model, the argon gas inputted by the gas inlet 3 can share the gas outlet at the bottom of the single crystal furnace, and is discharged from the gas outlet at the bottom of the main furnace chamber of the single crystal furnace after the cooling effect is completed. No additional gas outlet is required, and the original setting is fully utilized to maximize the use of the original function. In this way, by providing an air inlet 3 on the wall of the auxiliary furnace chamber 1 between every two adjacent insulation rings 2, the single crystal silicon rod 10 pulled to the auxiliary furnace chamber 1 can be cooled. Argon gas is simultaneously inputted from multiple air inlets 3, which can accelerate the cooling process of a specific temperature zone and shorten the cooling time.
[0051] It should also be noted that the argon gas flow rate range of the air inlet 3 is 25slpm-50slpm. If the flow rate of the air inlet 3 is less than 25slpm, the cooling effect is not significant, and the cooling time in the specific temperature zone is not significantly shortened; if the flow rate of the air inlet 3 is greater than 50slpm, the gas flow rate is too large, and airflow disturbance is likely to occur, blowing the single crystal silicon rod 10, resulting in an unstable crystal pulling process and a risk of tilting and breaking.
[0052] In an optional embodiment provided by the present utility model, please refer to Figure 1 , the thickness of the heat-insulating ring 2 ranges from 1 to 2 cm. Specifically, in some embodiments, the thickness of the heat-insulating ring 2 is 1 to 2 cm; further, in some embodiments, the thickness of the heat-insulating ring 2 is 1 to 1.5 cm; further, in some embodiments, the thickness of the heat-insulating ring 2 is 1.5 to 2 cm; if the thickness of the heat-insulating ring 2 is less than 1 cm, since the heat-insulating ring 2 is made of stainless steel, stainless steel is metal, and metal conducts heat quickly, the heat-insulating ring 2 will not have a heat-insulating effect; if the thickness of the heat-insulating ring 2 is greater than 2 cm, since the thickness of the heat-insulating ring 2 is too thick, more stainless steel is consumed, resulting in increased costs, and the heat-insulating effect will not be further increased due to the increase in the thickness of the heat-insulating ring 2. In this way, by limiting the thickness of the heat-insulating ring 2 to the range of 1 to 2 cm, while ensuring the heat-insulating effect, the production cost can also be taken into account.
[0053] In a second aspect, in an optional embodiment of the present invention, the present invention further provides a single crystal furnace, comprising a main furnace chamber and the auxiliary furnace chamber 1 as described above which is connected to the main furnace chamber.
[0054] For details, please refer to Figure 1In an optional embodiment of the utility model, the single crystal furnace includes a main furnace chamber and an auxiliary furnace chamber 1 connected to the main furnace chamber, the auxiliary furnace chamber 1 includes a plurality of insulation rings 2, along the radial direction of the auxiliary furnace chamber 1, the insulation rings 2 are fixed to the inner wall of the auxiliary furnace chamber 1 by welding, the heat rings are made of stainless steel, the outer diameter R2 of the insulation rings is equal to the inner diameter r1 of the auxiliary furnace chamber, since the diameter of the single crystal silicon rod 10 is 253-263mm, in order to ensure that the insulation rings 2 are not in direct contact with the single crystal silicon rod 10, the inner diameter r2 of the insulation rings is in the range of 300-400mm, and the thickness of the insulation rings 2 is 1-2cm; The auxiliary furnace chamber 1 also includes a plurality of air inlets 3, the air inlet 3 is located between every two adjacent insulation rings 2, the air inlet 3 is used to connect an external argon gas source, and the argon gas entering the auxiliary furnace chamber 1 is finally discharged through the air outlet at the bottom of the main furnace chamber of the single crystal furnace; in the process of crystal pulling, when the shoulder is released and the equal diameter growth begins, the temperature inside the main furnace chamber of the single crystal furnace is 1420℃-1480℃, and the crystal rise driver drives the single crystal silicon rod 10 to rise slowly. When the single crystal silicon rod 10 enters the auxiliary furnace chamber 1, due to the isolation effect of the insulation ring 2, the heat radiation of the silicon melt in the main furnace chamber to the single crystal silicon rod 10 is reduced, and it is away from the single crystal. Under the action of the multi-layer heat-insulating ring 2, the heat dissipation rate of the middle and upper parts of the single crystal silicon rods 10 in the main furnace chamber of the furnace is faster than that of the middle and lower parts of the single crystal silicon rods 10 close to the main furnace chamber of the single crystal furnace. As the single crystal silicon rods 10 gradually rise, the temperature of the single crystal silicon rods 10 gradually decreases. When they rise to a position 3 meters above the bottom of the auxiliary furnace chamber 1, the temperature of the single crystal silicon rods 10 corresponding to this position drops to about 600°C. When the single crystal silicon rods 10 are completely pulled to the heat-insulating ring 2 at the bottom of the auxiliary furnace chamber 1, since the middle and lower parts of the single crystal silicon rods 10 are closer to the main furnace chamber, due to the existence of the thermal radiation effect, The temperature of the single crystal silicon rod 10 at one end close to the main furnace chamber cools down slowly. At this time, the air inlet 3 between two adjacent insulation rings 2 is opened, and argon gas is input at a flow rate of 25slpm-50slpm. Since the spacing between the two adjacent insulation rings 2 near one end of the main furnace chamber is smaller than the spacing between the two adjacent insulation rings 2 away from the end of the main furnace chamber, the arrangement density of the air inlet 3 near one end of the main furnace chamber is smaller than the arrangement density of the air inlet 3 away from one end of the main furnace chamber, so that the middle and lower parts of the single crystal silicon rod 10 near the bottom of the auxiliary furnace chamber 1 can accelerate the cooling rate and shorten the cooling time.
[0055] In summary, the auxiliary furnace chamber and the single crystal furnace provided by the utility model achieve at least the following beneficial effects:
[0056] By arranging multiple heat-insulating rings and arranging multiple air inlets in the partition interval formed by the heat-insulating rings, the multiple heat-insulating rings form a physical partition, which reduces the heat radiation of the single crystal furnace liquid surface to the auxiliary furnace chamber. Arranging multiple air inlets in the partition interval can effectively increase the cooling rate of the single crystal silicon rod after entering the auxiliary furnace chamber, shorten the cooling time of the single crystal silicon rod at a specific temperature, reduce the dislocation caused by the brittle-ductile transition of the single crystal silicon rod when the temperature changes, improve the quality of the single crystal silicon rod, save the turnover time of the single crystal silicon rod, increase the speed of straight-pulling single crystals, and thus improve the production efficiency of the single crystal silicon rod; the heat-insulating ring is arranged as a circular ring structure, the process is simple, and it is convenient for mass production; by limiting the range of the inner and outer diameters of the heat-insulating ring, the heat-insulating ring can be prevented from loosening from the wall of the auxiliary furnace chamber, and a certain gap can be maintained with the single crystal silicon rod while achieving the partition effect, so as to prevent the single crystal silicon rod from being squeezed or damaged. By setting insulation rings at intervals in the area 5 meters above the bottom of the auxiliary furnace chamber, multiple insulation rings can also form multiple partition intervals, which can form multiple barriers to the liquid surface of the single crystal furnace; the distance between two adjacent insulation rings close to the bottom of the auxiliary furnace chamber is set to be smaller than the distance between two adjacent insulation rings away from the bottom of the auxiliary furnace chamber, which can better block the heat radiation of the single crystal furnace liquid to the bottom of the single crystal silicon rod, accelerate the cooling rate of the single crystal silicon rod in a specific temperature zone, and reduce the number of defects. The insulation ring is made of stainless steel, which is the same or similar to the material of the auxiliary furnace chamber. During welding, the intermolecular force between the insulation ring and the auxiliary furnace chamber can be greater, and the welding can be more firmly achieved. By adjusting and optimizing the position of the air inlet, the cooling rate in a specific temperature zone can be flexibly controlled, and the time that the single crystal silicon rod is in different temperature zones during cooling can be adjusted, so as to achieve the effect of improving the quality of the single crystal silicon rod. By setting an air inlet on the wall of the auxiliary furnace chamber between every two adjacent insulation rings, the single crystal silicon rod pulled to the auxiliary furnace chamber can be cooled. Argon gas is simultaneously input from multiple air inlets, which can speed up the cooling process in a specific temperature zone and shorten the cooling time. By limiting the thickness of the insulation ring to the range of 1-2cm, the production cost can be taken into account while ensuring the insulation effect.
[0057] Although some specific embodiments of the present invention have been described in detail by way of examples, it should be understood by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present invention. It should be understood by those skilled in the art that the above embodiments may be modified without departing from the scope and spirit of the present invention. The scope of the present invention is defined by the appended claims.
Claims
1. A secondary furnace chamber, characterized in that: include A plurality of heat-insulating rings, wherein the heat-insulating rings are fixed to the inner wall of the auxiliary furnace chamber, and the plane where the heat-insulating rings are located is parallel to the cross section of the auxiliary furnace chamber; A plurality of air inlets are provided, wherein the air inlets are located in the partitioning interval formed by the heat insulating ring, and the air inlets are used for connecting to an external argon gas source.
2. The auxiliary furnace chamber according to claim 1, characterized in that: The insulation ring comprises an inner diameter and an outer diameter. The outer diameter of the insulation ring is equal to the inner diameter of the auxiliary furnace chamber. The inner diameter of the insulation ring ranges from 300 to 400 mm.
3. The auxiliary furnace chamber according to claim 2, characterized in that: The heat-insulating rings are arranged at intervals within a range of 5 meters upward along the bottom of the auxiliary furnace chamber; wherein, one heat-insulating ring is fixed to the bottom of the inner wall of the auxiliary furnace chamber.
4. The auxiliary furnace chamber according to claim 3, characterized in that: The distance between two adjacent insulation rings close to the bottom of the auxiliary furnace chamber is smaller than the distance between two adjacent insulation rings far from the bottom of the auxiliary furnace chamber.
5. The auxiliary furnace chamber according to claim 4, characterized in that: The heat insulation ring is connected to the inner wall of the auxiliary furnace chamber by welding.
6. The auxiliary furnace chamber according to claim 5, characterized in that: The heat insulation ring is made of stainless steel.
7. The auxiliary furnace chamber according to claim 1, characterized in that: The air inlet is located within a range of 3 meters above the bottom of the auxiliary furnace chamber.
8. The auxiliary furnace chamber according to claim 7, characterized in that: An air inlet is arranged on the auxiliary furnace chamber wall between every two adjacent insulation rings.
9. The auxiliary furnace chamber according to claim 8, characterized in that: The thickness of the thermal insulation ring ranges from 1 to 2 cm.
10. A single crystal furnace, characterized in that: It comprises a main furnace chamber and an auxiliary furnace chamber as described in any one of claims 1 to 9 which is connected to the main furnace chamber.