Graphite head and polycrystalline silicon reduction furnace
By designing a graphite head with a first tapered section and a guide groove, the risk of silicon rod inverter furnace in the polysilicon production process is solved, and the stability of the silicon rod and the safety of the production process are achieved.
Patent Information
- Application Number
- CN202421201347.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-29
- Publication Date
- 2025-02-25
- Estimated Expiration
- 2034-05-29
AI Technical Summary
During the polysilicon production process, the volume of the silicon rod gradually increases during the growth process, resulting in a weak zone at the connection between the silicon rod and the graphite head, increasing the risk of the silicon rod pouring (rewind furnace) in the reduction furnace.
A graphite head is designed, with the first end connected to the silicon core and the second end connected to the graphite holder of the polysilicon reduction furnace. The graphite head is provided with a first conical section and a guide groove, which extends in the axial direction of the graphite head to guide the crystallization of silicon atoms in the raw material gas and enhance the connection between the graphite head and the silicon core.
By enhancing the connection between the graphite head and the silicon core, the risk of the silicon rod inverter furnace is reduced, ensuring the stability of the silicon rod and the safety of the production process.
Smart Images
Figure CN222524191U_ABST
Abstract
Description
Technical Field
[0001] The present application relates to polysilicon production technology, and in particular to a graphite head and a polysilicon reduction furnace. Background Art
[0002] Polysilicon is the main raw material for the production of semiconductors and solar photovoltaic products. The main methods for producing polysilicon currently include the modified Siemens method, the silane method, the fluidized bed method, etc. Among them, the modified Siemens method and the silane method both require the deposition of carriers during the reduction process. The widely used carrier in the modified Siemens method is the silicon core, and the silicon core and the electrode are connected and clamped by graphite parts.
[0003] In the related technology, during the polysilicon production process, power can be supplied to the silicon core to heat the silicon core to make it red until the surface temperature reaches over one thousand degrees Celsius. At the same time, gas containing silicon raw materials and reducing gas are introduced to cause the raw material gas to undergo a reduction reaction at high temperature, causing the silicon molecules in the raw material gas to gradually accumulate on the silicon core, forming a silicon rod of a predetermined diameter.
[0004] In the polysilicon reduction furnace, the silicon core is connected to the graphite seat through a graphite head. As the volume of the silicon rod gradually increases during the growth process, a weak area will be formed at the connection between the silicon rod and the graphite head, increasing the risk of the silicon rod tipping over (falling over) in the reduction furnace. Utility Model Content
[0005] The present application provides a graphite head and a polysilicon reduction furnace, which are used to solve the problem of easy furnace failure during silicon rod production in the related art.
[0006] On the one hand, the present application provides a graphite head, which is applied to a polysilicon reduction furnace, wherein a first end of the graphite head is connected to a silicon core, and a second end of the graphite head is connected to a graphite seat of the reduction furnace;
[0007] The first end of the graphite head is provided with a first conical section, the outer diameter of the first conical section gradually increases in the direction from the first end to the second end of the graphite head, and the first conical section is provided with a first mounting hole extending along the axial direction thereof;
[0008] A plurality of guide grooves are arranged on the outer wall of the first conical section. The plurality of guide grooves are arranged at intervals in the circumferential direction of the first conical section, and each guide groove extends along the axial direction of the graphite head.
[0009] In some embodiments, the plurality of guide grooves are evenly spaced in the circumferential direction of the first tapered segment, and the angle between two adjacent guide grooves is between 30° and 60°.
[0010] In some embodiments, a second conical section is disposed at the second end of the graphite head, a straight section is disposed between the second conical section and the first conical section, and an outer diameter of the second conical section gradually increases in a direction from the second end to the first end of the graphite head.
[0011] In some embodiments, the guide groove has a first end and a second end that are arranged opposite to each other, the first end of the guide groove is arranged close to the end surface of the first end of the graphite head, and the second end of the guide groove extends to the connection between the first conical section and the straight section, or the second end of the guide groove extends to the straight section.
[0012] In some embodiments, the distance between the first end of the guide groove and the end surface of the first end of the graphite head is between 1 mm and 2 mm.
[0013] In some embodiments, the width of the guide groove is between 0.5 mm and 1 mm.
[0014] In some embodiments, the height of the graphite head is between 90 mm and 100 mm.
[0015] In some embodiments, an exhaust channel is also provided in the graphite head, and the exhaust channel includes a first exhaust section and a second exhaust section, the first exhaust section passes through the end surface of the second end of the graphite head and is connected to the first mounting hole, and the second exhaust section is connected to the first exhaust section and the outer wall of the graphite head.
[0016] On the other hand, the present application provides a polysilicon reduction furnace, comprising the above-mentioned graphite head.
[0017] In some embodiments, the polysilicon reduction furnace includes: a reduction furnace body; an electrode disposed at the bottom of the reduction furnace body; a graphite seat disposed in the reduction furnace body, the graphite seat connecting the electrode and the graphite head, and the graphite head and the electrode are in contact and fit.
[0018] The first end of the graphite head provided in the present application is provided with a first conical section, and the outer diameter of the first conical section gradually increases in the direction from the first end to the second end of the graphite head shown. This arrangement makes it easier for the silicon rod to escape when separated from the graphite head. In addition, since the silicon core is heated by the electrode and is in a high temperature state, the closer the graphite head is to the silicon core, the higher the temperature is. Therefore, the closer the graphite head is to the silicon core, the easier it is to crystallize. The closer the first conical section is to the silicon core, the smaller the diameter is, which can make the diameter of the silicon column crystallized on the graphite head more uniform, thereby ensuring the stability of the silicon rod. A plurality of guide grooves are provided on the outer wall of the first conical section, and the plurality of guide grooves are arranged at intervals in the circumferential direction of the first conical section, and each guide groove extends along the axial direction of the graphite head. After the polysilicon reduction furnace is started, the raw gas and the reducing gas are continuously blown toward the silicon core, and the guide groove can contact the raw gas and the reducing gas, so that the gas flow flows toward the silicon core along the guide groove. In addition to being able to crystallize on the silicon core, the silicon in the raw gas can also crystallize on the graphite head, and the guide groove extending along the axial direction of the graphite head further helps to guide the silicon crystals to the graphite head, thereby increasing the length of the graphite head wrapped by silicon crystals, and then strengthening the connection between the graphite head and the silicon core, reducing the risk of silicon rod furnace failure. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.
[0020] Figure 1 A cross-sectional view of a graphite head provided in an embodiment of the present application;
[0021] Figure 2 A top view of a graphite head provided in an embodiment of the present application;
[0022] Figure 3 A schematic diagram of the assembly structure of a graphite head and a graphite seat provided in an embodiment of the present application.
[0023] Description of reference numerals:
[0024] 100, graphite head;
[0025] 110, first tapered section;
[0026] 120, straight section;
[0027] 130, second tapered section;
[0028] 140, guide groove;
[0029] 150, first mounting hole;
[0030] 160, exhaust passage; 161, first exhaust section; 162, second exhaust section;
[0031] 200, graphite seat; 210, second mounting hole; 220, third mounting hole;
[0032] 300. Electrode. DETAILED DESCRIPTION
[0033] In order to make the purpose, technical solutions and advantages of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.
[0034] Due to the rapid development of the photovoltaic industry, the demand for high-purity polysilicon raw materials has grown rapidly. At present, most of the processes for producing polysilicon raw materials abroad are trichlorosilane hydrogen reduction method, that is, modified Siemens method. Both the modified Siemens method and the silane method require the deposition of carriers during the reduction process. The widely used carrier in the modified Siemens method is silicon core, and the silicon core and the electrode are connected and clamped by graphite parts.
[0035] There are two main types of graphite components for polysilicon reduction furnaces: one is a three-piece set, including a graphite seat, a fixing ring and a graphite clip. The other is a two-piece set, including a graphite seat and a graphite head. The graphite seat and the graphite head in the two-piece set are socket-type structures, and the upper end of the graphite seat is provided with a mounting hole for placing the graphite head. The graphite head can be stably plugged into the graphite seat and connected to the electrode set in the graphite seat.
[0036] During the polysilicon production process, the electrodes are energized to heat the silicon core until the surface temperature reaches over one thousand degrees Celsius. At the same time, gas containing silicon raw materials and reducing gas are introduced to cause the raw material gas to undergo a reduction reaction at high temperature, causing the silicon molecules in the raw material gas to gradually accumulate on the silicon core, forming a silicon rod of a predetermined diameter.
[0037] However, the silicon core is connected to the graphite seat through a graphite head. As the volume of the silicon rod gradually increases during the growth process, the difference between the diameter of the silicon rod and the diameter of the graphite head gradually increases, thereby forming a weak area at the connection between the silicon rod and the graphite head. In addition, gas needs to be introduced into the reduction furnace, which puts the silicon rod in a non-static environment, increasing the risk of the silicon rod tipping over (falling over) in the reduction furnace.
[0038] In view of this, the present application provides a graphite head, the first end of the graphite head can be connected to the silicon core, and the second end can be connected to the graphite seat. A guide groove is arranged on the graphite head, and the guide groove extends along the axial direction of the graphite head, so that the silicon atoms in the raw gas can be crystallized on the silicon core and also on the graphite head, so that the length of the graphite head wrapped by the silicon crystals is increased, thereby strengthening the connection between the graphite head and the silicon core and reducing the risk of silicon rod overturning.
[0039] Figure 1 A cross-sectional view of a graphite head provided in an embodiment of the present application; Figure 2 A top view of a graphite head provided in an embodiment of the present application; Figure 3 A schematic diagram of the assembly structure of a graphite head and a graphite seat provided in an embodiment of the present application.
[0040] like Figures 1 to 3 As shown, the graphite head 100 provided in the embodiment of the present application is applied to a polysilicon reduction furnace, the first end of the graphite head 100 is connected to the silicon core, the second end of the graphite head 100 is connected to the graphite seat 200 of the reduction furnace, and the graphite seat 200 is provided with an electrode 300, which can generate heat after being energized, so that the silicon core is in a high-temperature state, and at the same time, raw gas containing silicon element and reducing gas having a reducing effect are also circulated in the polysilicon reduction furnace, the raw gas and the reducing gas flow in the polysilicon reduction furnace, and continuously contact with the silicon core, so that the silicon in the raw gas can crystallize on the silicon core, so that the diameter of the silicon core is continuously increased to form a silicon rod.
[0041] The first end of the graphite head 100 is provided with a first tapered section 110, and the outer diameter of the first tapered section 110 gradually increases in the direction from the first end to the second end of the graphite head 100 shown. This arrangement makes it easier for the silicon rod to be removed from the graphite head 100 when it is separated. In addition, since the silicon core is heated by the electrode and is in a high temperature state, the closer the graphite head is to the silicon core, the higher the temperature is. Therefore, the closer the graphite head is to the silicon core, the easier it is to crystallize. The closer the first tapered section 110 is to the silicon core, the smaller the diameter is, which can make the diameter of the silicon column crystallized on the graphite head 100 more uniform, thereby ensuring the stability of the silicon rod.
[0042] In addition, the outer diameter of the first tapered section 110 gradually increases from the first end to the second end of the graphite head 100, so that the graphite head 100 has better support stability for the silicon core, thereby helping to reduce the risk of silicon rod overturning.
[0043] Furthermore, a first mounting hole 150 extending along the axial direction is provided in the first conical section 110, and the first mounting hole 150 is used to plug the silicon core. Specifically, the silicon core includes a silicon core body and a plug-in column provided at the end of the silicon core body, and the plug-in column can be plugged into the first mounting hole 150, thereby realizing a fixed connection between the silicon core and the graphite head 100.
[0044] like Figures 1 to 3 As shown, a plurality of guide grooves 140 are provided on the outer wall of the first tapered section 110 . The plurality of guide grooves 140 are arranged at intervals in the circumferential direction of the first tapered section 110 , and each guide groove 140 extends along the axial direction of the graphite head 100 .
[0045] In the above structure, after the polysilicon reduction furnace is started, the raw gas and the reducing gas are continuously blown toward the silicon core, and the guide groove 140 can contact the raw gas and the reducing gas, so that the gas flow flows toward the silicon core along the guide groove 140. In addition to being able to crystallize on the silicon core, the silicon in the raw gas can also be crystallized on the graphite head 100, and the guide groove 140 extending along the axial direction of the graphite head further helps to guide the silicon crystals to the graphite head 100, thereby increasing the length of the graphite head 100 wrapped by the silicon crystals, thereby strengthening the connection between the graphite head and the silicon core, and reducing the risk of silicon rod furnace failure.
[0046] It should also be noted that, since the guide groove 140 is provided on the outer surface of the first conical section 110, the roughness of the outer surface of the first conical section 110 is increased, making it easier for silicon to crystallize on the graphite head 100, thereby helping to connect the silicon core and the silicon column crystallized on the outer surface of the graphite head 100 into a whole, further enhancing the strength of the connection between the graphite head 100 and the silicon core, thereby further reducing the risk of silicon rod overturning.
[0047] like Figure 1 and Figure 2As shown, in some embodiments, a plurality of guide grooves 140 are evenly spaced in the circumferential direction of the first tapered section 110 , and an angle between two adjacent guide grooves 140 is between 30° and 60°.
[0048] In the above structure, the multiple guide grooves 140 are evenly spaced to make the silicon columns crystallized on the graphite head 100 more uniform, thereby ensuring the stability of the silicon rods, reducing the risk of silicon rod tilting and thus reducing the risk of silicon rod falling over.
[0049] In addition, the angle between two adjacent guide grooves 140 is between 30° and 60°, which helps to increase the roughness of the outer surface of the first tapered section 110 , making it easier for silicon to crystallize on the graphite head 100 .
[0050] Exemplarily, the specific values of the angle between two adjacent guide grooves 140 include but are not limited to 30°, 40°, 45°, 50°, 55°, 60°, etc., and the embodiments of the present application do not specifically limit this.
[0051] like Figures 1 to 3 As shown, in some embodiments, the second end of the graphite head 100 is provided with a second tapered section 130, a straight section 120 is provided between the second tapered section 130 and the first tapered section 110, and the outer diameter of the second tapered section 130 gradually increases in the direction from the second end to the first end of the graphite head 100.
[0052] In the above structure, the second end of the graphite head 100 can be connected to the second mounting hole 210 on the graphite seat 200. Specifically, the shape of the second mounting hole 210 is adapted to the second tapered section 130 of the graphite head 100, and the second tapered section 130 of the graphite head 100 can be tightly connected to the second mounting hole 210, so that the graphite head 100 can be stably fixed, reducing the risk of the graphite head 100 and the graphite seat 200 being separated.
[0053] It should be noted that the end surface of the first end of the graphite head 100 plays the role of supporting the silicon core body. If the area of the end surface of the first end of the graphite head 100 is too small, its support for the silicon core body will be weakened. Therefore, it is necessary to pay attention to the opening position of the guide groove 140. Specifically, Figure 1 As shown, in some embodiments, the guide groove 140 has a first end and a second end that are relatively arranged, and the first end of the guide groove 140 is arranged close to the end surface of the first end of the graphite head 100. Since there is a distance between the first end of the guide groove 140 and the end surface of the first end of the graphite head 100, the opening of the guide groove 140 will not reduce the contact area between the first end of the graphite head 100 and the silicon core body, thereby ensuring the supporting stability of the graphite head 100 to the silicon core.
[0054] Exemplarily, the second end of the guide groove 140 may extend to the connection between the first tapered section 110 and the straight section 120 to ensure the extension length of the silicon column crystallized on the graphite head 100 .
[0055] In other embodiments, the second end of the guide groove 140 may also extend to the straight section 120 to further extend the length of the silicon column crystallized on the graphite head 100. However, it is necessary to ensure that a predetermined distance is maintained between the second end of the guide groove 140 and the graphite seat 200 to reduce the probability of silicon crystallization on the graphite seat 200, thereby facilitating the removal of the silicon rod.
[0056] Specifically, Figure 2 As shown, in some embodiments, the distance between the first end of the guide groove 140 and the end surface of the first end of the graphite head 100 is between 1 mm and 2 mm. Exemplarily, the distance between the first end of the guide groove 140 and the end surface of the first end of the graphite head 100 can take values including but not limited to 1 mm, 1.5 mm, 2 mm, etc.
[0057] like Figure 2 As shown, in some embodiments, the width of the guide groove 140 is between 0.5 mm and 1 mm. Such a configuration can make it easier for silicon to crystallize in the guide groove 140 and then diffuse outward from the guide groove 140 to form a silicon column on the graphite head 100 .
[0058] Exemplarily, the width of the guide groove 140 may include, but is not limited to, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, and 1 mm.
[0059] like Figure 1 As shown, the closer the graphite head 100 is to the silicon core, the higher the temperature is. If the length of the graphite head 100 is set too long, it is not easy for the position of the graphite head 100 far away from the silicon core to crystallize into silicon pillars. Therefore, the height of the graphite head 100 can be lowered to reduce the temperature attenuation of the graphite head 100, so that the graphite head 100 is more covered by crystallized silicon pillars, thereby further reducing the risk of silicon rod furnace failure.
[0060] Specifically, the height of the graphite head 100 is between 90 mm and 100 mm. Exemplarily, the height of the graphite head 100 may take values including but not limited to 90 mm, 91 mm, 92 mm, 93 mm, 94 mm, 95 mm, 96 mm, 97 mm, 98 mm, 99 mm, 100 mm, etc.
[0061] like Figure 1 and Figure 3As shown, in some embodiments, an exhaust channel 160 is further provided in the graphite head 100, and the exhaust channel 160 includes a first exhaust section 161 and a second exhaust section 162. The first exhaust section 161 passes through the end surface of the second end of the graphite head 100 and is connected to the first mounting hole 150, and the second exhaust section 162 is connected to the first exhaust section 161 and the outer wall of the graphite head 100.
[0062] In the above structure, since the operating temperature in the polysilicon reduction furnace can be greater than one thousand degrees Celsius, the gas in the holes opened on the graphite head 100 and the graphite seat 200 will expand due to the heat, and the exhaust channel 160 can discharge the gas in the graphite head 100 and the graphite seat 200, thereby ensuring the stable installation of the graphite head 100 and the graphite seat 200.
[0063] It should be noted that the second exhaust section 162 is connected to the first exhaust section 161 and the outer wall of the graphite head 100. In order to reduce the probability of the second exhaust section 162 being blocked by silicon crystals, the second exhaust section 162 can be
[0064] On the other hand, the embodiment of the present application further provides a polysilicon reduction furnace, comprising the above-mentioned graphite head 100. Since the above-mentioned graphite head 100 has the effect of reducing the risk of silicon rod failure, the polysilicon reduction furnace having the same also has the effect of reducing the risk of silicon rod failure.
[0065] Specifically, in some embodiments, the polysilicon reduction furnace includes: a reduction furnace body, an electrode 300 and a graphite seat 200 .
[0066] The electrode 300 is arranged at the bottom of the reduction furnace body, and can heat the silicon core after power is turned on; the graphite seat 200 is arranged in the reduction furnace body, and the graphite seat 200 connects the electrode and the graphite head 100, and the graphite head 100 and the electrode are in contact and matched. Specifically, the graphite seat 200 is provided with a second mounting hole 210 and a third mounting hole 220 connected to the second mounting hole 210, and the second mounting hole 210 is matched with the second conical section 130 of the graphite head 100 for mounting the graphite head 100. The third mounting hole 220 is matched with the electrode 300 for mounting the electrode 300, and the graphite head 100 can be in contact with the electrode 300, so that the silicon core connected to the graphite head 100 can heat up when the electrode 300 is powered on, so that the silicon in the raw gas can crystallize and form a silicon rod.
[0067] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, or it can be an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.
[0068] In the description of the present application, it should be understood that the terms "upper", "lower", "front", "back", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.
[0069] The terms "first", "second", "third", "fourth", etc. (if any) in the specification and claims of this application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the application described herein can be implemented in an order other than those illustrated or described herein, for example.
[0070] In addition, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus that includes a series of steps or elements is not necessarily limited to those steps or elements explicitly listed, but may include other steps or elements not explicitly listed or inherent to such process, method, product, or apparatus.
[0071] Finally, it should be noted that the above implementation modes are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned implementation modes, a person of ordinary skill in the art should understand that the technical solutions described in the aforementioned implementation modes can still be modified, or some or all of the technical features therein can be replaced by equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the implementation modes of the present application.
Claims
1. A graphite head, used in a polysilicon reduction furnace, characterized in that: The first end of the graphite head is connected to the silicon core, and the second end of the graphite head is connected to the graphite seat of the reduction furnace; The first end of the graphite head is provided with a first conical section, the outer diameter of the first conical section gradually increases in the direction from the first end to the second end of the graphite head, and the first conical section is provided with a first mounting hole extending along the axial direction thereof; A plurality of guide grooves are arranged on the outer wall of the first conical section. The plurality of guide grooves are arranged at intervals in the circumferential direction of the first conical section, and each of the guide grooves extends along the axial direction of the graphite head.
2. The graphite head according to claim 1, characterized in that: The plurality of guide grooves are evenly spaced in the circumferential direction of the first conical section, and an angle between two adjacent guide grooves is between 30° and 60°.
3. The graphite head according to claim 1, characterized in that: The second end of the graphite head is provided with a second tapered section, a straight section is provided between the second tapered section and the first tapered section, and the outer diameter of the second tapered section gradually increases in the direction from the second end to the first end of the graphite head.
4. The graphite head according to claim 3, characterized in that: The guide groove has a first end and a second end that are arranged opposite to each other, the first end of the guide groove is arranged close to the end surface of the first end of the graphite head, and the second end of the guide groove extends to the connection between the first conical section and the straight section, or the second end of the guide groove extends to the straight section.
5. The graphite head according to claim 4, characterized in that: The distance between the first end of the guide groove and the end surface of the first end of the graphite head is between 1 mm and 2 mm.
6. The graphite head according to claim 1, characterized in that: The width of the guide groove is between 0.5 mm and 1 mm.
7. The graphite head according to any one of claims 1 to 6, characterized in that: The height of the graphite head is between 90 mm and 100 mm.
8. The graphite head according to any one of claims 1 to 6, characterized in that: An exhaust channel is also provided in the graphite head, and the exhaust channel includes a first exhaust section and a second exhaust section, the first exhaust section passes through the end surface of the second end of the graphite head and is connected to the first mounting hole, and the second exhaust section is connected to the first exhaust section and the outer wall of the graphite head.
9. A polysilicon reduction furnace, characterized in that: include: The graphite head according to any one of claims 1 to 8.
10. The polysilicon reduction furnace according to claim 9, characterized in that: include Reduction furnace body; An electrode is arranged at the bottom of the reduction furnace body; A graphite seat is arranged in the reduction furnace body, the graphite seat connects the electrode and the graphite head, and the graphite head and the electrode are in contact and fit.