Outer guide cylinder of Czochralski single crystal furnace
By setting an annular flange on the bottom end surface of the cylinder outside the single crystal furnace, the flow path of argon gas is changed, so that the argon gas flows close to the straight wall above the junction of the silicon liquid and the crucible, the silicon liquid in the prior art is solved The problem of slow heat dissipation and excessive temperature at the crucible junction achieves the effect of reducing the oxygen content of single crystal silicon rods and the risk of crucible bulging.
Patent Information
- Application Number
- CN202323455433.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2023-12-19
- Publication Date
- 2025-02-14
- Estimated Expiration
- 2033-12-19
AI Technical Summary
The bottom oblique design of the existing single-crystal furnace outer diversion cylinder causes the heat dissipation of slower heat at the junction of silicon liquid and the crucible, and the temperature is too high, which increases the risk of oxygen precipitation and the bulging and edge collapse of the crucible.
Design a direct pulling single crystal furnace outer flow guide cylinder, with an annular flange on the bottom end of the barrel, so that argon gas is blocked through the annular flange during the flow process, flowing downwards around the flange, and closes to the silicon liquid and the crucible. The straight wall above the junction flows, taking away more heat.
Effectively reduces the temperature of the straight wall above the junction of the silicon liquid and the crucible, reduces the oxygen content in the single crystal silicon rod, improves the quality of the single crystal silicon rod, reduces the probability of bulging of the crucible, extends the crucible usage time and reduces the use of the crucible cost.
Smart Images
Figure CN222476818U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of single crystal furnaces, in particular to an external guide tube of a CZ single crystal furnace. Background Art
[0002] Monocrystalline silicon is an important semiconductor material, widely used in photovoltaic, electronics, communications and other fields. With the promotion of policies and the continuous improvement of technology, the number of monocrystalline silicon production enterprises in my country has increased year by year, and the competition has become increasingly fierce. The output and quality of monocrystalline silicon are the core competitiveness of monocrystalline silicon production enterprises, and whether the design of the thermal field of the single crystal furnace is reasonable plays a decisive role in the output and quality of monocrystalline silicon. The design of the guide tube of the single crystal furnace is a very important part of the thermal field design. The function and principle of the guide tube of the single crystal furnace is to control the gas flow mode by adjusting the components, which can effectively control the volatilization of the latent heat of crystallization at the solid-liquid interface of the crystal, thereby effectively maintaining the flatness of the solid-liquid interface, and at the same time play a heat preservation effect, isolating the heat source from baking the water-cooled screen. It includes a cylinder with a diameter gradually decreasing from top to bottom, which is made of high-purity graphite or quartz, and an outer cylinder is provided on the outer peripheral surface of the cylinder, and an insulation space is provided between the outer cylinder and the cylinder, and an insulation material layer is provided in the insulation space.
[0003] In order to reduce the contact area between argon and the outer chamber, reduce the path of argon passing through the liquid surface, and reduce the temperature fluctuation caused by argon on the liquid surface, the outer guide tubes currently used in single crystal furnaces are all in the form of bottom bevels. However, this also causes the straight wall above the junction of silicon liquid and crucible to lack argon blowing, slow heat dissipation and excessive temperature, which increases the precipitation of oxygen in the crucible and the risk of crucible bulging and collapse. Utility Model Content
[0004] The technical problem to be solved by the utility model is to overcome the disadvantages of the prior art and provide an external guide tube for a CZ single crystal furnace.
[0005] In order to solve the above technical problems, the technical solution of the utility model is as follows:
[0006] A guide tube outside a CZ single crystal furnace comprises a tube body, wherein the tube body comprises a tube body and a tube bottom connected to the lower end of the tube body;
[0007] The cylinder body is a hollow cylindrical structure with two ends open, the cylinder bottom is a hollow inverted truncated cone structure with two ends open, the upper bottom surface of the cylinder bottom is connected with the lower bottom surface of the cylinder body, and the opening of the lower bottom surface of the cylinder bottom is a rectifying hole;
[0008] Wherein, the lower end surface of the cylinder bottom is provided with an annular flange protruding downward, and the annular flange is located at the edge of the lower end surface of the cylinder bottom.
[0009] As a preferred solution of the external guide tube of the CZ single crystal furnace of the utility model, the cross section of the annular flange is streamlined.
[0010] As a preferred solution of the external guide tube of the CZ single crystal furnace of the utility model, the inner diameter of the tube body is equal to the inner diameter of the bottom surface of the tube bottom, and the diameter of the annular flange is equal to the inner diameter of the tube body.
[0011] As a preferred solution of the external guide tube of the CZ single crystal furnace of the utility model, the height of the annular flange is half of the height of the bottom of the tube.
[0012] As a preferred solution of the external guide tube of the CZ single crystal furnace of the utility model, an ear is fixedly provided on the upper end of the tube body, and the ear is annular and coaxially arranged on the outer side of the tube body.
[0013] As a preferred solution of the external guide tube of the vertical pulling single crystal furnace described in the utility model, wherein: a plurality of mounting holes are pierced in the ear portion, and the plurality of mounting holes are evenly arranged on a circumference with the center of the circle of the cross section of the tube body as the center.
[0014] As a preferred solution of the external guide tube of the CZ single crystal furnace of the utility model, the angle between the side surface of the bottom of the tube and the horizontal plane is 30°.
[0015] As a preferred solution of the external guide tube of the CZ single crystal furnace described in the utility model, wherein: the tube body is made of carbon-carbon composite material.
[0016] The beneficial effects of the utility model are:
[0017] The utility model sets an annular flange on the lower end surface of the bottom of the cylinder, so that when the argon gas climbs up and flows along the side of the bottom of the cylinder, it will be blocked by the annular flange and flow downward to bypass the annular flange. When the argon gas bypasses, it will flow close to the straight wall above the junction of the silicon liquid and the crucible, so that it can take away more heat from the straight wall of the crucible, so that the temperature of the straight wall above the junction of the silicon liquid and the crucible is reduced, which can effectively reduce the oxygen content of the single crystal silicon rod, improve the quality of the single crystal silicon rod, and reduce the concentric circle ratio of the silicon wafer. At the same time, the reduction in the temperature of the straight wall above the junction of the crucible will also reduce the probability of bulging of the crucible, extend the use time of the crucible, and reduce the cost of using the crucible. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.
[0019] Figure 1 A schematic diagram of the structure of the external guide tube of the CZ single crystal furnace provided by the utility model;
[0020] Figure 2 A schematic diagram of the working of the guide tube formed by the guide tube outside the CZ single crystal furnace provided by the utility model;
[0021] Among them: 1. Cylinder body; 2. Cylinder body; 3. Cylinder bottom; 4. Rectification hole; 5. Annular flange; 6. Ear. DETAILED DESCRIPTION
[0022] In order to make the content of the utility model more clearly understood, the utility model is further described in detail below according to specific implementation methods and in combination with the accompanying drawings.
[0023] Figure 1 The schematic diagram of the structure of the guide tube outside the CZ single crystal furnace provided in the present application. The device comprises a cylinder 1, and the cylinder 1 comprises a cylinder body 2 and a cylinder bottom 3. Among them, an annular flange 5 is arranged at the bottom of the cylinder bottom 3. When the argon gas rises along the side of the cylinder bottom 3, it is blocked by the annular flange 5, so that the argon gas flows downward and bypasses the annular flange 5, taking away more heat from the straight wall of the crucible, so that the temperature of the straight wall above the junction of the silicon liquid and the crucible is reduced.
[0024] Specifically, the cylinder body 2 is a cylindrical structure that is hollow and open at both ends. The cylinder bottom 3 is an inverted truncated cone structure that is hollow and open at both ends. Figure 1 The upper bottom surface of the cylinder bottom 3 is connected to the lower bottom surface of the cylinder body 2. The opening provided on the lower bottom surface of the cylinder bottom 3 is a rectifying hole 4.
[0025] It should be noted that the inner diameter of the cylinder body 2 is equal to the inner diameter of the upper bottom surface of the cylinder bottom 3, so as to ensure the smoothness and sealing of the connection between the cylinder body 2 and the cylinder bottom 3.
[0026] The lower end surface of the cylinder bottom 3 is provided with an annular flange 5 protruding downwards, see Figure 1 The annular flange 5 is located at the edge of the lower end surface of the cylinder bottom 3 , that is, the diameter of the annular flange 5 is equal to the inner diameter of the cylinder body 2 .
[0027] See also Figure 2 By providing the annular flange 5, the argon gas will flow downward and bypass the annular flange 5 when it is climbing up along the side of the bottom 3 of the cylinder, blocked by the annular flange 5. When bypassing, the argon gas will flow close to the upper straight wall at the junction of the silicon liquid and the crucible, so as to take away more heat from the straight wall of the crucible, reduce the temperature of the straight wall above the junction of the silicon liquid and the crucible, effectively reduce the oxygen content of the single crystal silicon rod, improve the quality of the single crystal silicon rod, and reduce the concentric circle ratio of the silicon wafer; at the same time, the reduction of the straight wall temperature above the junction of the crucible will also reduce the probability of crucible bulging, extend the service life of the crucible, and reduce the cost of using the crucible.
[0028] Preferably, the cross section of the annular flange 5 is configured to be streamlined, see Figure 1 and Figure 2 This ensures that the argon gas will flow closely along the upper straight wall at the junction of the silicon liquid and the crucible when flowing through the annular flange 5, thereby taking away more heat from the straight wall of the crucible.
[0029] The height of the annular flange 5 is half of the height of the cylinder bottom 3 .
[0030] See also Figure 1 , an ear 6 is fixedly installed at the upper end of the barrel 2. The ear 6 is annular and coaxially arranged on the outside of the barrel 2. A plurality of mounting holes are pierced in the ear 6. Each mounting hole penetrates the ear 6 in the vertical direction. A plurality of mounting holes are evenly arranged on the same circumference with the center of the cross-section circle of the barrel 2 as the center. The above-mentioned mounting holes are used for the guide tube connection mechanism to pass through and be fixed, and are hung on the water-cooling screen crossbar.
[0031] Preferably, the outer guide tube body 1 is made of carbon-carbon composite material. Carbon-carbon composite material carbon fiber and its fabric-reinforced carbon matrix composite material have the advantages of low density (<2.0g / cm3), high strength, high specific modulus, low expansion coefficient, good friction performance, good thermal shock resistance, high dimensional stability, etc.
[0032] In this embodiment, the angle between the side of the cylinder bottom 3 and the horizontal plane is 30°. The thickness of the cylinder bottom 3 is 12 mm, and the thickness of the cylinder body 2 is 10 mm. The height of the cylinder body 1 of the entire outer guide cylinder is 600 mm. The ear portion 6 has a thickness of 20 mm and a width of 40 mm, and the diameter of the mounting hole opened thereon is 15 mm.
[0033] The oxygen in the single crystal silicon rod is mainly brought into the melt from the crucible due to factors such as crystal rotation, crucible rotation, and thermal convection of the melt, and then enters the crystal through crystal growth. The reaction is: SiO2+Si=2SiO↑. The higher the temperature, the faster the reaction rate, and the more oxygen is brought into the melt. Therefore, the external guide tube of the vertical pulling single crystal furnace provided in the present application can effectively reduce the oxygen content of the single crystal silicon rod by changing the flow path of argon gas to reduce the temperature of the straight wall above the junction of the silicon liquid and the crucible, reduce the precipitation of oxygen in the crucible, and reduce the oxygen content of the single crystal silicon rod.
[0034] In addition, the quartz crucible will become soft at high temperatures. If the sintering temperature exceeds its temperature resistance limit, it will be distorted, deformed, and even bulge. Therefore, lowering the temperature of the straight wall above the junction of the silicon liquid and the crucible will also reduce the probability of bulging of the crucible.
[0035] Therefore, the technical solution of the present application can effectively reduce the oxygen content of the single crystal silicon rod, improve the quality of the single crystal silicon rod, and reduce the concentric circle ratio of the silicon wafer by guiding the argon gas to flow close to the straight wall above the junction of the silicon liquid and the crucible, so as to reduce the temperature of the straight wall above the junction of the silicon liquid and the crucible, thereby reducing the probability of bulging of the crucible, prolonging the use time of the crucible, and reducing the cost of using the crucible.
[0036] In addition to the above embodiments, the present invention may also have other implementation modes; any technical solutions formed by equivalent replacement or equivalent transformation shall fall within the protection scope required by the present invention.
Claims
1. A guide tube outside a CZ single crystal furnace, characterized in that: The invention comprises a cylinder (1), wherein the cylinder (1) comprises a cylinder body (2) and a cylinder bottom (3) connected to the lower end of the cylinder body (2); The cylinder body (2) is a hollow cylindrical structure with openings at both ends, the cylinder bottom (3) is a hollow inverted truncated cone structure with openings at both ends, the upper bottom surface of the cylinder bottom (3) is in contact with the lower bottom surface of the cylinder body (2), and the opening of the lower bottom surface of the cylinder bottom (3) is a rectifying hole (4); The lower end surface of the cylinder bottom (3) is provided with an annular flange (5) protruding downward, and the annular flange (5) is located at the edge of the lower end surface of the cylinder bottom (3).
2. The guide tube outside the CZ single crystal furnace according to claim 1, characterized in that: The cross section of the annular flange (5) is streamlined.
3. The guide tube outside the CZ single crystal furnace according to claim 1, characterized in that: The inner diameter of the barrel body (2) is equal to the inner diameter of the upper bottom surface of the barrel bottom (3), and the diameter of the annular flange (5) is equal to the inner diameter of the barrel body (2).
4. The guide tube outside the CZ single crystal furnace according to claim 1, characterized in that: The height of the annular flange (5) is half the height of the cylinder bottom (3).
5. The guide tube outside the CZ single crystal furnace according to claim 1, characterized in that: An ear portion (6) is fixedly provided at the upper end of the barrel body (2); the ear portion (6) is annular and is coaxially arranged on the outer side of the barrel body (2).
6. The guide tube outside the CZ single crystal furnace according to claim 5, characterized in that: The ear portion (6) is provided with a plurality of mounting holes, and the plurality of mounting holes are evenly arranged on a circumference with the center of the cross-section circle of the barrel (2) as the center.
7. The guide tube outside the CZ single crystal furnace according to claim 1, characterized in that: The angle between the side surface of the cylinder bottom (3) and the horizontal plane is 30°.
8. The guide tube outside the Czochralski single crystal furnace according to claim 1, characterized in that: The cylinder (1) is made of a carbon-carbon composite material.