Single crystal furnace

Abstract

A single crystal furnace, comprising a bottom plate coaxially arranged at the bottom of the single crystal furnace. The single crystal furnace further comprises a gas extraction hood provided on an inner side of the bottom plate. A gas output channel of the gas extraction hood is connected to a gas extraction hole provided in the bottom plate, and a gas intake channel of the gas extraction hood extends upwards in an axial direction of the single crystal furnace and is in communication with a furnace chamber of the single crystal furnace; and the gas intake channel of the gas extraction hood extends to the position above a bottom heater at the bottom of the single crystal furnace. The single crystal furnace comprises the gas extraction hood, the gas intake channel of the gas extraction hood extends to the position above the bottom heater in the single crystal furnace, and the gas extraction hood extracts high-temperature tail gas in the single crystal furnace from the position above the bottom heater, such that control over the flow direction of the high-temperature tail gas can be realized, the high-temperature tail gas is prevented from scouring and corroding the bottom heater, and the service life of the bottom heater is prolonged. Moreover, the high-temperature tail gas directly flows out from the gas extraction hole in the bottom plate by means of the gas extraction hood, the high-temperature tail gas can be prevented from corroding a bottom heat preservation layer at the bottom of the furnace chamber, and the service life of the bottom heat preservation layer is prolonged, thus reducing the production cost.

Description

A single crystal furnace Technical Field

[0001] The present invention belongs to the technical field of single crystal silicon production and manufacturing equipment, and in particular relates to a single crystal furnace. Background Art

[0002] Monocrystalline silicon is a semiconductor material generally used to manufacture integrated circuits and other electronic components. As countries around the world pay more and more attention to the solar photovoltaic industry, the application of silicon solar cells continues to expand, the demand for solar cells is increasing, and the demand for monocrystalline silicon materials is also expanding year-on-year.

[0003] Currently, there are two techniques for growing single crystal silicon: the zone melting method and the Czochralski method, with the Czochralski method being the most commonly used. In the Czochralski method, polycrystalline silicon is placed in a quartz crucible and heated to a high temperature to melt it. A seed crystal is then lowered from the top into the molten polysilicon. By controlling the temperature of the liquid surface, the molten polysilicon recrystallizes around the seed crystal, forming neatly arranged single crystal silicon rods.

[0004] When polycrystalline silicon melts, silicon monoxide particles are volatilized. At high temperatures, these particles react with graphite and carbon / carbon thermal field accessories such as the heater and crucible holder within the single crystal furnace, thereby reducing the service life of these accessories. Furthermore, as silicon single crystals grow and crystallize from solution, they release heat. This heat slows the crystallization rate and affects silicon single crystal production efficiency. Therefore, during the Czochralski silicon single crystal growth process, argon gas must be continuously introduced into the single crystal furnace to mix with the silicon monoxide and impurity dust generated within the furnace. While argon is continuously introduced into the single crystal furnace, a vacuum pump is used to vent the mixed gas out of the furnace.

[0005] Existing single crystal furnaces typically introduce argon into the furnace chamber from the top of the furnace and extract it from the bottom. However, the extraction holes in existing single crystal furnaces are generally located below the bottom heater at the bottom of the furnace. As the high-temperature exhaust gas is extracted, it passes through the bottom heater. The high-temperature exhaust gas can reach temperatures of up to 1400°C, constantly eroding the bottom heater and causing severe corrosion. This affects the performance of the bottom heater and can even damage and render it useless.

[0006] Therefore, designing a single crystal furnace that can prevent high-temperature exhaust gas from scouring the bottom heater has become a technical problem that needs to be solved urgently by those skilled in the art. Summary of the Invention

[0007] The present invention provides a single crystal furnace, comprising an exhaust hood, which is used to extract high-temperature exhaust gas in the single crystal furnace from above the bottom heater, thereby controlling the flow direction of the high-temperature exhaust gas, preventing the high-temperature exhaust gas from scouring and corroding the bottom heater, and solving the problem of low service life of the bottom heater in the existing single crystal furnace.

[0008] In order to solve the above technical problems, the basic concept of the technical solution adopted in the present invention is: a single crystal furnace, including a base plate coaxially arranged at the bottom of the single crystal furnace, and also including an exhaust hood, which is arranged on the inner side of the bottom plate of the single crystal furnace, and its exhaust channel is connected to the exhaust holes opened on the bottom plate of the single crystal furnace, and its air inlet channel extends upward along the axial direction of the single crystal furnace and is connected to the furnace cavity of the single crystal furnace; the air inlet channel of the exhaust hood extends to above the bottom heater at the bottom of the single crystal furnace.

[0009] Furthermore, the exhaust hood includes an exhaust hood body, which includes side walls, a top wall and a bottom wall that surround each other to form an exhaust cavity. The exhaust hood body is arranged at the bottom of the furnace cavity. The air inlet channel and the air outlet channel of the exhaust hood are both connected to the exhaust cavity and extend from the top and bottom of the exhaust cavity respectively along the axial direction of the single crystal furnace away from the exhaust cavity.

[0010] Furthermore, the exhaust hood is provided with a plurality of exhaust holes on the bottom plate that are arranged at intervals around the axis of the furnace cavity, and the exhaust cavities of each exhaust hood are connected with the furnace cavity through an air inlet channel, and are connected with the exhaust holes one by one through an air outlet channel; or, the exhaust cavities of the exhaust hood extend along the circumference of the furnace cavity, a plurality of air inlet channels are provided along the circumference of the furnace cavity, and a plurality of air outlet channels are provided that are connected with each exhaust hole one by one.

[0011] Furthermore, it also includes an auxiliary exhaust hood, which is arranged on one side of the exhaust hood, including an auxiliary exhaust hood body and an auxiliary air intake channel arranged on the top of the auxiliary exhaust hood body, and the auxiliary exhaust hood body is connected to the exhaust hood body of the exhaust hood through an air guide pipe; the auxiliary exhaust hood body is the same shape as the exhaust hood body, and the auxiliary air intake channel is the same shape as the air intake channel.

[0012] Furthermore, the side walls of the exhaust hood main body and the auxiliary exhaust hood main body include: a first side wall, which is arranged on the side away from the axis of the single crystal furnace and is in contact with the inner wall of the furnace cavity; a second side wall, which is arranged on the side close to the axis of the single crystal furnace, and includes a planar portion extending radially from both ends of the first side wall toward the direction close to the axis of the single crystal furnace, and an arc-shaped portion connected between the two planar portions and protruding and extending toward the side close to the axis of the single crystal furnace; both ends of the air guide pipe are respectively connected to the arc-shaped portions of the second side walls of the exhaust hood main body and the auxiliary exhaust hood main body.

[0013] Furthermore, the auxiliary exhaust hood is arranged between two adjacent exhaust hoods, and the auxiliary exhaust hood body is communicated with the exhaust hood bodies of the two adjacent exhaust hoods through an air duct.

[0014] Furthermore, plug connectors are respectively provided at both ends of the air duct, and the plug connectors at both ends of the air duct are respectively plugged into the auxiliary exhaust hood body and the second side wall of the exhaust hood body; the top and bottom surfaces of the auxiliary exhaust hood body, the exhaust hood body and the air duct are respectively on the same horizontal plane.

[0015] Furthermore, a bottom insulation layer is provided at the bottom of the single crystal furnace, and the bottom insulation layer includes a first bottom insulation layer, a second bottom insulation layer and a third bottom insulation layer arranged in sequence from bottom to top; the exhaust hood body of the exhaust hood is embedded in the second bottom insulation layer, and its thickness is adapted to the thickness of the second bottom insulation layer, the air inlet channel extends upward through the third insulation layer, and the air outlet channel extends downward through the first insulation layer.

[0016] Furthermore, the air inlet channel of the exhaust hood is arranged to be arc-shaped along the radial cross-section of the single crystal furnace; the side of the air inlet channel of the exhaust hood away from the axis of the single crystal furnace is in contact with the inner wall of the furnace cavity, and the side of the air inlet channel of the exhaust hood close to the axis of the single crystal furnace is parallel to the inner wall of the furnace cavity and is spaced apart from the outer edge of the bottom heater.

[0017] Furthermore, a crucible is provided in the furnace chamber, and the distance between the inner wall of the air inlet channel of the exhaust hood close to the axis of the single crystal furnace and the inner wall on the side away from the axis of the single crystal furnace is less than or equal to the gap between the crucible and the inner wall of the furnace chamber; the extension height of the air inlet channel of the exhaust hood is less than or equal to the bottom height of the crucible.

[0018] Furthermore, it also includes a bottom pressure plate, which is arranged at the bottom of the furnace chamber, and the outer peripheral wall is in contact with the inner wall of the furnace chamber. A notch corresponding to the air inlet channel of the exhaust hood is provided on the outer peripheral wall of the bottom pressure plate, and the air inlet channel of the exhaust hood is embedded in the notch; preferably, the bottom pressure plate is of a spliced ​​type, including multiple split plates arranged along the circumference of the single crystal furnace.

[0019] After adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art.

[0020] 1. The present invention provides a single crystal furnace including an exhaust hood, and provides an air inlet channel of the exhaust hood extending to above the bottom heater in the single crystal furnace, so that the exhaust hood can suck the high-temperature exhaust gas in the single crystal furnace from above the bottom heater, thereby achieving flow direction control of the high-temperature exhaust gas, preventing the high-temperature exhaust gas from scouring and corroding the bottom heater, and improving the service life of the bottom heater; at the same time, the high-temperature exhaust gas directly flows out from the exhaust holes on the bottom plate through the exhaust hood, which can also prevent the high-temperature exhaust gas from corroding the bottom insulation layer at the bottom of the furnace cavity, thereby improving the service life of the bottom insulation layer and reducing production costs.

[0021] 2. The present invention provides an exhaust hood including an exhaust hood main body, an air inlet channel provided on the top of the exhaust hood main body and provided as an arc-shaped structure fitted with the inner wall of the furnace chamber, so that the air flow flows through the gap between the crucible and the inner wall of the furnace chamber and directly enters the air inlet channel of the exhaust hood, which can prevent the air flow from diffusing to the bottom of the crucible. At the same time, it can increase the layout area of ​​the bottom heater and improve the heating efficiency.

[0022] 3. The present invention increases the suction area of ​​the exhaust gas flow and improves the suction effect by setting an auxiliary exhaust hood. Even if there are fewer exhaust holes at the bottom of the single crystal furnace, a higher suction efficiency can be guaranteed, thereby improving the adaptability of the exhaust structure to the existing single crystal furnace.

[0023] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings are part of the present invention and are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention, but do not constitute an improper limitation of the present invention. Obviously, the drawings described below are only some embodiments. For ordinary technicians in this field, other drawings can be obtained based on these drawings without inventive work. In the drawings: Figure 1 is a schematic diagram of the internal structure of the single crystal furnace in the embodiment of the present invention; Figure 2 is a cross-sectional view of the single crystal furnace in the embodiment of the present invention; Figure 3 is a schematic diagram of the installation structure of the exhaust structure in the embodiment of the present invention; Figure 4 is a schematic diagram of the overall structure of the exhaust structure in the embodiment of the present invention; Figure 5 is a schematic diagram of the structure of the exhaust hood in the embodiment of the present invention; Figure 6 is a schematic diagram of the structure of the auxiliary exhaust hood in the embodiment of the present invention; Figure 7 is a schematic diagram of the structure of the air guide pipe in the embodiment of the present invention.

[0025] Description of the main components in the figure: 1. Single crystal furnace; 11. Bottom plate; 12. Electrode hole; 13. Main insulation layer; 14. Furnace cavity; 2. Bottom insulation layer; 21. First bottom insulation layer; 22. Second bottom insulation layer; 23. Third bottom insulation layer; 3. Exhaust hood; 31. Air inlet channel; 32. Exhaust hood body; 33. Air outlet channel; 34. Plug slot; 4. Auxiliary exhaust hood; 41. Auxiliary air inlet channel; 42. Auxiliary exhaust hood body; 5. Main heater; 6. Bottom heater; 7. Crucible; 8. Crucible support; 81. Crucible shaft; 82. Crucible tray; 9. Bottom pressure plate; 91. Split plate; 10. Air guide tube; 101. Plug connector.

[0026] It should be noted that these drawings and textual descriptions are not intended to limit the conceptual scope of the present invention in any way, but rather to illustrate the concept of the present invention for those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. The following embodiments are used to illustrate the present invention but are not used to limit the scope of the present invention.

[0028] In the description of the present invention, it should be noted that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "inside", "outside", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the present invention.

[0029] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood broadly. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; and direct or indirect connections through an intermediary. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0030] The single crystal furnace 1 includes a furnace body and a furnace cover. The top of the furnace body is open and includes a bottom plate 11 arranged at the bottom of the furnace body and a furnace wall arranged above the bottom plate 11. The bottom plate 11 is circular and the furnace wall is cylindrical. The bottom plate 11 is arranged at the lower end of the furnace wall and is used to seal the lower end of the furnace wall. The furnace cover is buckled on the top of the furnace body. The furnace cover and the furnace body are buckled to form a furnace cavity 14.

[0031] The crucible 7 includes a quartz crucible and a graphite crucible, or the crucible 7 includes a quartz crucible and a carbon / carbon crucible, and is arranged in the furnace chamber 14 through a crucible support 8. The crucible support 8 includes a crucible shaft 81 that coaxially passes through the bottom plate 11 of the single crystal furnace 1 from the bottom of the single crystal furnace 1 and extends into the furnace chamber 14, and a crucible tray 82 is arranged at the upper end of the crucible shaft 81. A graphite crucible or a carbon / carbon crucible is arranged on the crucible tray 82, and a quartz crucible is arranged in the graphite crucible or the carbon / carbon crucible. The quartz crucible is used to hold polycrystalline silicon.

[0032] A main insulation layer 13 is provided on the inner side of the furnace wall, and a bottom insulation layer 2 is provided on the inner side of the bottom plate 11. The bottom insulation layer 2 and the main insulation layer 13 surround each other to form a furnace chamber 14 of the single crystal furnace 1. A main heater 5 is provided on the outer periphery of the crucible holder 8, and the main heater 5 coaxially surrounds the outer periphery of the graphite crucible or carbon / carbon crucible. A bottom heater 6 is also provided below the crucible 7. The diameter of the bottom heater 6 is smaller than the inner diameter of the bottom of the furnace chamber 14. Preferably, the diameter of the bottom heater 6 is greater than or equal to the outer diameter of the crucible 7 and is coaxial with the crucible 7.

[0033] In this embodiment, the main heater 5 and the bottom heater 6 are respectively fixed to the bottom of the furnace body by electrode bolts and connected to the heating electrodes at the bottom of the furnace body.

[0034] In this embodiment, before single crystal furnace 1 is operated, a vacuum pump located at an exhaust port on bottom plate 11 exhausts all air from within furnace 1. Argon is then introduced from the top of furnace 1. During operation, silicon monoxide and dust impurities continuously form above the quartz crucible within furnace 1. Therefore, while argon is continuously introduced, the vacuum pump simultaneously exhausts a mixture of silicon monoxide, dust impurities, and argon.

[0035] The gas flows from the top of single crystal furnace 1 into the quartz crucible, removing silicon monoxide particles generated by the melting of polycrystalline silicon and heat generated by single crystal crystallization. The gas then flows from above the quartz crucible through the gap between crucible holder 8 and the inner wall of furnace chamber 14 to the bottom of single crystal furnace 1, where it is discharged through the exhaust holes in bottom plate 11. This effectively prevents silicon monoxide from reacting with components such as the heater and graphite crucible or carbon / carbon crucible within the furnace, extending their service life. Furthermore, the heat generated by crystallization is removed by the protective gas, increasing the crystallization rate and, consequently, production efficiency.

[0036] However, in the existing single crystal furnace 1, the exhaust hole is generally set below the bottom heater 6 at the bottom of the single crystal furnace 1. When the high-temperature exhaust gas is extracted, it will pass through the bottom heater 6. The temperature of the high-temperature exhaust gas can reach 1400°C, which continuously flushes the bottom heater 6, causing serious gas corrosion, affecting the use of the bottom heater 6, and even causing the bottom heater 6 to be damaged and scrapped.

[0037] There is also a single crystal furnace in the prior art, whose exhaust port is set on the side of the furnace body. Although this solution can reduce the impact of high-temperature exhaust gas on the bottom heater to a certain extent, this solution will cause serious damage to the thermal field of the single crystal furnace. During the exhaust process, the heat in the single crystal furnace is seriously dissipated.

[0038] In this embodiment, a single crystal furnace is provided, and the exhaust structure of the single crystal furnace draws the high-temperature exhaust gas in the single crystal furnace 1 from above the bottom heater 6, which can control the flow direction of the high-temperature exhaust gas, avoid the high-temperature exhaust gas from eroding and corroding the bottom heater 6, and solve the problem of low service life of the bottom heater 6 in the existing single crystal furnace 1.

[0039] Specifically, as shown in Figure 2, the exhaust structure includes an exhaust hood 3, which is installed on the inner side of the bottom plate 11 of the single crystal furnace 1. The exhaust hood 3 includes an air inlet channel 31 and an air outlet channel 33. The air outlet channel 33 of the exhaust hood 3 is connected to the exhaust hole opened on the bottom plate 11. The air inlet channel 31 of the exhaust hood 3 extends upward along the axial direction of the single crystal furnace 1 and extends to above the bottom heater 6 at the bottom of the single crystal furnace 1.

[0040] Thus, the vacuum pump draws the high-temperature exhaust gas from the single crystal furnace 1 from above the bottom heater 6 through the exhaust hood 3, thereby controlling the flow direction of the high-temperature exhaust gas, preventing the high-temperature exhaust gas from scouring and corroding the bottom heater 6, and thus increasing the service life of the bottom heater 6. Simultaneously, the high-temperature exhaust gas flows directly out of the exhaust holes on the bottom plate 11 through the exhaust hood 3, thereby preventing the high-temperature exhaust gas from corroding the bottom insulation layer 2 at the bottom of the furnace chamber 14, thereby increasing the service life of the bottom insulation layer 2 and reducing production costs. Furthermore, in this embodiment, by drawing the exhaust gas from the bottom of the single crystal furnace, the integrity of the thermal field within the single crystal furnace can be ensured, heat loss can be reduced, and the single crystal production process can be made more energy-efficient.

[0041] In this embodiment, the exhaust hood 3 also includes an exhaust cavity, which is arranged at the bottom of the furnace cavity 14. The air inlet channel 31 and the air outlet channel 33 of the exhaust hood 3 are both connected to the exhaust cavity, and extend from the top and bottom of the exhaust cavity respectively along the axial direction of the single crystal furnace 1 away from the exhaust cavity.

[0042] In this embodiment, exhaust hood 3 first draws exhaust gas into an exhaust chamber through inlet passage 31 for buffering, and then discharges the exhaust gas through outlet passage 33. This improves the stability of exhaust gas flow during the extraction process and prevents airflow turbulence. Furthermore, positioning the exhaust chamber at the bottom of furnace cavity 14 effectively utilizes the temperature of the exhaust gas flow within the exhaust chamber, improving the thermal insulation of the bottom of furnace cavity 14 and reducing heat loss.

[0043] In some possible embodiments, the exhaust cavity includes multiple independent cavities. Specifically, the exhaust hood 3 is provided with multiple exhaust holes on the bottom plate 11 that are spaced apart and arranged around the axis of the furnace cavity 14. The exhaust cavity of each exhaust hood 3 is connected to the furnace cavity 14 through the air inlet channel 31, and is connected to the exhaust holes one by one through the air outlet channel 33.

[0044] In other possible embodiments, the exhaust cavity is configured as a complete cavity. Specifically, the exhaust cavity of the exhaust hood 3 extends along the circumference of the furnace cavity 14, and the air inlet channel 31 is provided with one extending along the circumference of the furnace cavity 14, or the air inlet channel 31 is provided with multiple air inlet channels 31 arranged at intervals along the circumference of the furnace cavity 14, and the air outlet channel 33 is provided with multiple air outlet channels 33 that are connected to each exhaust hole in a one-to-one correspondence.

[0045] In this embodiment, a plurality of the air outlet channels 33 are provided, which are coaxially corresponding to the air extraction holes on the bottom plate. That is, the number of the air outlet channels 33 is the same as the number of the air extraction holes.

[0046] Preferably, a plurality of intake channels 31 may be provided along a circumferential direction, and the number of intake channels 31 may be greater than or equal to the number of outlet channels 33. Further preferably, two intake channels 31 are provided, and the gap between the two intake channels 31 is used to avoid the two legs of the main heater, thereby preventing high-temperature exhaust gas from corroding the two legs of the main heater.

[0047] That is, in this embodiment, two air inlet channels 31 are provided, extending along the circumference of the air extraction cavity and arranged at intervals along the circumference of the air extraction cavity. The two air inlet channels 31 are staggered with the two legs of the main heater.

[0048] Embodiment 1 As shown in FIG. 1 to FIG. 3 , in the embodiment of the present invention, an exhaust structure of a single crystal furnace is introduced, which is arranged at the bottom of the single crystal furnace 1 .

[0049] Specifically, as shown in Figure 2, the exhaust structure includes an exhaust hood 3, which is an independent component. The exhaust hood 3 is installed on the inner side of the bottom plate 11 of the single crystal furnace 1. The exhaust hood 3 includes an air inlet channel 31 and an air outlet channel 33. The air outlet channel 33 of the exhaust hood 3 is connected to the exhaust hole opened on the bottom plate 11. The air inlet channel 31 of the exhaust hood 3 extends upward along the axial direction of the single crystal furnace 1 and extends to above the bottom heater 6 at the bottom of the single crystal furnace 1.

[0050] Thus, the vacuum pump sucks the high-temperature exhaust gas in the single crystal furnace 1 from above the bottom heater 6 through the exhaust hood 3, which can control the flow direction of the high-temperature exhaust gas, avoid the high-temperature exhaust gas from scouring and corroding the bottom heater 6, and improve the service life of the bottom heater 6; at the same time, the high-temperature exhaust gas directly flows out from the exhaust holes on the bottom plate 11 through the exhaust hood 3, and can also avoid the high-temperature exhaust gas from corroding the bottom insulation layer 2 at the bottom of the furnace cavity 14, thereby improving the service life of the bottom insulation layer 2 and reducing production costs.

[0051] Preferably, in this embodiment, the air inlet channel 31 of the exhaust hood 3 is configured to have an arc-shaped cross-section along the radial direction of the single crystal furnace 1. Specifically, the side of the air inlet channel 31 of the exhaust hood 3 away from the axis of the single crystal furnace 1 is parallel to the inner wall of the furnace chamber 14 and is arranged close to the inner wall of the furnace chamber 14. Preferably, the side of the air inlet channel 31 of the exhaust hood 3 away from the axis of the single crystal furnace 1 is aligned with the inner wall of the furnace chamber 14, and the side of the air inlet channel 31 of the exhaust hood 3 close to the axis of the single crystal furnace 1 is parallel to the inner wall of the furnace chamber 14 and is spaced apart from the outer edge of the bottom heater 6. Thus, the airflow can flow through the gap between the crucible 7 and the inner wall of the furnace chamber 14 and directly enter the air inlet channel 31 of the exhaust hood 3, thereby preventing the airflow from diffusing below the crucible 7. At the same time, the layout area of ​​the bottom heater 6 can be increased, thereby improving heating efficiency.

[0052] In this embodiment, the crucible 7 includes a quartz crucible and a graphite crucible, or the crucible 7 includes a quartz crucible and a carbon / carbon crucible.

[0053] Preferably, in this embodiment, the radial width of the air inlet channel 31 of the exhaust hood 3 is adapted to the width of the gap between the outer wall of the crucible 7 and the inner wall of the furnace chamber 14, and the outer wall of the crucible 7 is the outer wall of a graphite crucible or a carbon / carbon crucible.

[0054] Preferably, in this embodiment, the distance between the inner wall of the air inlet channel 31 of the exhaust hood 3 on the side close to the axis of the single crystal furnace 1 and the inner wall on the side away from the axis of the single crystal furnace 1 is less than or equal to the gap between the crucible 7 and the inner wall of the furnace chamber 14. Preferably, the diameter of the inner wall of the air inlet channel 31 of the exhaust hood 3 on the side close to the axis of the single crystal furnace 1 is greater than the outer diameter of the graphite crucible or carbon / carbon crucible, thereby preventing high-temperature exhaust gas from flowing toward the side close to the axis of the single crystal furnace 1, reducing erosion and corrosion of the outer peripheral wall of the graphite crucible or carbon / carbon crucible.

[0055] Further preferably, in this embodiment, the upward extension length of the air inlet channel 31 of the exhaust hood 3 may be further increased to prevent the air flow from diffusing downwards to the crucible 7 .

[0056] Preferably, the extension height of the air inlet channel 31 of the exhaust hood 3 is less than or equal to the bottom height of the crucible 7. Alternatively, the air inlet channel 31 of the exhaust hood 3 may extend to be flush with the outer periphery of the crucible tray 82.

[0057] In this embodiment, the exhaust hood 3 includes an exhaust hood body 32, and the exhaust hood body 32 includes side walls, a top wall and a bottom wall that surround each other to form an exhaust cavity. The side walls, top wall and bottom wall are respectively plates of uniform thickness. The air inlet channel 31 and the air outlet channel 33 of the exhaust hood 3 are respectively arranged on the bottom wall and the top wall, and the air inlet channel 31 and the air outlet channel 33 are both connected to the exhaust cavity.

[0058] Specifically, in this embodiment, the exhaust hood 3 is a split structure, and the air inlet channel 31, the air outlet channel 33, and the exhaust hood body 32 are respectively provided as independent components, which are spliced ​​together during installation.

[0059] In this embodiment, the hood body 32 includes an outer shell and an upper cover. The bottom wall and side walls of the hood body 32 are integrally formed to form an outer shell with an open top. The top wall of the hood body 32 can be detachably fastened to the top of the side wall to form the upper cover.

[0060] Preferably, the shape of the upper cover matches the shape of the top of the housing. A snap-fitting groove extending downward along the inner side of the top of the side wall is provided at the top opening of the housing. A first plug-in portion having a shape matching the shape of the snap-fitting groove is provided at the lower end of the upper cover. The lower end of the upper cover abuts the bottom of the snap-fitting groove, and the upper cover around the first plug-in portion abuts the upper end of the side wall. The outer peripheral wall of the upper cover is coplanar with the outer side of the side wall, and the inner peripheral wall of the upper cover is coplanar with the inner side of the side wall.

[0061] In this embodiment, the air inlet channel 31 of the exhaust hood 3 is configured as a cylinder with openings at both ends. An air inlet is provided on the top wall of the exhaust hood body 32, and an extension port is provided around the air inlet and extending upward. The lower end of the air inlet channel 31 is sleeved on the extension port.

[0062] The air outlet channel 33 of the exhaust hood 3 is configured as a cylinder with both ends open. An air outlet corresponding to the air extraction hole is formed on the bottom wall of the exhaust hood body 32, and the upper end of the air outlet channel 33 is inserted into the air outlet. Specifically, a second plug-in portion having a diameter smaller than the overall outer diameter of the air outlet channel 33 is provided at the upper end of the air outlet channel 33. The diameter of the second plug-in portion matches the diameter of the air outlet. The second plug-in portion is inserted into the air outlet, and the end of the second plug-in portion is flush with the bottom inner wall of the air extraction chamber. The air outlet channel 33 on the outer periphery of the second plug-in portion abuts against the outer side of the bottom wall of the air extraction chamber.

[0063] Preferably, in this embodiment, the gas outlet and gas outlet channel 33 are coaxially arranged with the gas extraction hole provided in the bottom plate 11. Furthermore, the shape of the gas outlet channel 33 matches the shape of the gas extraction hole. The gas outlet channel 33 is inserted into the gas extraction hole and connected to the vacuum pump. In this embodiment, the gas outlet channel is configured as an elongated cylindrical shape, which can further reduce heat loss within the single crystal furnace.

[0064] In this embodiment, the sidewalls of the exhaust hood body 32 include a first sidewall and a second sidewall that surround each other. The first sidewall is arranged on a side away from the axis of the single crystal furnace 1, parallel to the inner wall of the furnace chamber 14, and close to the inner wall of the furnace chamber 14. Preferably, the air inlet channel 31 of the exhaust hood 3 is aligned with the inner wall of the furnace chamber 14 on a side away from the axis of the single crystal furnace 1. The second sidewall is arranged on a side close to the axis of the single crystal furnace 1, and the two ends of the second sidewall are respectively connected to the two ends of the first sidewall. The second sidewall includes a planar portion extending radially from the two ends of the first sidewall toward the direction close to the axis of the single crystal furnace 1, and an arc-shaped portion connected between the two planar portions and protruding toward the side close to the axis of the single crystal furnace 1. The top wall and bottom wall of the exhaust hood body 32 are respectively adapted to the shapes of the upper and lower ends of the sidewall, and are respectively used to close the upper and lower ends of the sidewall.

[0065] The air inlet channel 31 of the exhaust hood 3 is arranged at the top of the exhaust hood main body 32, on the side away from the axis of the single crystal furnace 1, and the side of the air inlet channel 31 away from the axis of the single crystal furnace 1 is coplanar with the outer peripheral wall of the first side wall, and the left and right sides of the air inlet channel 31 extend along the radial direction of the single crystal furnace 1. The left and right sides of the air inlet channel 31 are respectively coplanar with the planar portion on the second side wall of the exhaust hood main body 32, and the extension length of the planar portion along the radial direction of the single crystal furnace 1 is greater than or equal to the extension length of the left and right sides of the air inlet channel 31 along the radial direction of the single crystal furnace 1.

[0066] In this embodiment, the exhaust hood 3 is provided with a plurality of exhaust holes arranged at intervals around the axis of the single crystal furnace 1 and corresponding one-to-one with the exhaust holes on the bottom plate 11. Specifically, in this embodiment, the bottom plate 11 of the single crystal furnace 1 has two exhaust holes, which are symmetrical with respect to a certain diameter of the bottom plate 11. Two exhaust hoods 3 are provided, and the gas outlet channels 33 of the two exhaust hoods 3 are respectively connected to one exhaust hole. The first side walls of the exhaust hood bodies 32 of the two exhaust hoods 3 are respectively in contact with the inner wall of the furnace chamber 14 of the single crystal furnace 1.

[0067] As shown in Figure 3, in this embodiment, a bottom insulation layer 2 is provided at the bottom of the single crystal furnace 1, and the exhaust hood body 32 of the exhaust hood 3 is embedded in the bottom insulation layer 2. The exhaust hood body 32 of the exhaust hood 3 is embedded in the middle of the bottom insulation layer 2 and extends radially along the single crystal furnace 1. The air inlet channel 31 of the exhaust hood 3 extends upward along the axial direction of the single crystal furnace 1 and is connected to the furnace cavity 14 of the single crystal furnace 1. The air outlet channel 33 of the exhaust hood 3 extends downward along the axial direction of the single crystal furnace 1 and is connected to the exhaust hole on the bottom plate 11 of the single crystal furnace 1. Preferably, the outer edge of the bottom insulation layer 2 extends to the inner wall of the furnace cavity 14. Specifically, the inner periphery of the bottom of the main insulation layer 13 is provided with a notch adapted to the outer edge of the bottom insulation layer 2, and the outer edge of the bottom insulation layer 2 extends to the notch at the bottom of the main insulation layer 13.

[0068] Specifically, the bottom insulation layer 2 includes a first bottom insulation layer 21, a second bottom insulation layer 22 and a third bottom insulation layer 23 arranged in sequence from bottom to top. The second bottom insulation layer 22 is provided with an opening adapted to the shape of the exhaust hood main body 32. The exhaust hood main body 32 is embedded in the opening of the second bottom insulation layer 22. The air outlet channel 33 of the exhaust hood 3 passes through the first bottom insulation layer 21 and extends to the exhaust hole. The air inlet channel 31 of the exhaust hood 3 passes through the third bottom insulation layer 23 and extends to the furnace cavity 14.

[0069] Preferably, in this embodiment, the thickness of the exhaust hood body 32 is adapted to the thickness of the second bottom insulation layer 22, the upper and lower sides of the exhaust hood body 32 are respectively fitted with the third insulation layer and the first insulation layer, the air inlet channel 31 extends upward through the third insulation layer, and the air outlet channel 33 extends downward through the first insulation layer.

[0070] In this embodiment, by embedding the exhaust hood body 32 in the bottom insulation layer 2, on the one hand, it is equivalent to setting up two heat sources in the bottom insulation layer 2, which can fully utilize the temperature of the high-temperature exhaust gas and improve the insulation effect of the bottom insulation layer 2. On the other hand, the bottom insulation layer 2 can be used to insulate the exhaust gas in the exhaust cavity, which can reduce heat loss.

[0071] In this embodiment, the single crystal furnace 1 also includes a bottom pressure plate 9, which is arranged at the bottom of the furnace cavity 14. The outer peripheral wall of the bottom pressure plate 9 is in contact with the inner wall of the furnace cavity 14. A notch corresponding to the air inlet channel 31 of the exhaust hood 3 is provided on the outer peripheral wall of the bottom pressure plate 9, and the air inlet channel 31 of the exhaust hood 3 is embedded in the notch.

[0072] In this embodiment, the bottom protection plate 9 is made of a hard material, specifically graphite. The inner wall of the notch in the bottom protection plate 9 is aligned with the side of the air inlet passage 31 of the exhaust hood 3 that is close to the axis of the single crystal furnace 1, as well as the left and right sides of the air inlet passage 31. This improves the installation stability of the bottom insulation layer 2 and the exhaust hood 3.

[0073] Preferably, in this embodiment, the bottom protection plate 9 is of a spliced ​​type, comprising a plurality of split plates 91 arranged along the circumference of the single crystal furnace 1. This makes it more convenient to install and transport the bottom protection plate 9.

[0074] Preferably, in this embodiment, the dividing line of the bottom protection pressure plate 9 extends along the radial direction of the single crystal furnace 1 . Further preferably, the dividing line is colinear with the symmetry line of the exhaust hood 3 .

[0075] Embodiment 2 As shown in FIG. 1 to FIG. 7 , in this embodiment, the exhaust structure of the single crystal furnace 1 further includes an auxiliary exhaust hood 4 .

[0076] Specifically, the auxiliary exhaust hood 4 is arranged on one side of the exhaust hood 3, including an auxiliary exhaust hood body 42, and an auxiliary air intake channel 41 arranged on the top of the auxiliary exhaust hood body 42, the auxiliary air intake channel 41 extends to above the bottom heater 6, and the auxiliary exhaust hood body 42 is connected to the exhaust hood body 32 of the exhaust hood 3 through the air guide pipe 10.

[0077] Preferably, in this embodiment, the auxiliary hood body 42 has the same shape as the hood body 32 of the hood 3 , and the auxiliary air inlet channel 41 of the auxiliary hood 4 has the same shape as the air inlet channel 31 of the hood 3 .

[0078] In this embodiment, the two exhaust hoods 3 are provided corresponding to the two exhaust holes on the bottom plate 11 , and the auxiliary exhaust hood 4 is provided between two adjacent exhaust hoods 3 .

[0079] Preferably, as shown in FIG4 , in this embodiment, two auxiliary exhaust hoods 4 are also provided. Specifically, the two exhaust hoods 3 are respectively provided on the first diameter of the single crystal furnace 1, and the two auxiliary exhaust hoods 4 are respectively provided on the second diameter of the single crystal furnace 1. The first diameter is perpendicular to the second diameter, and the two exhaust hoods 3 are symmetrical with respect to the second diameter, and the two auxiliary exhaust hoods 4 are symmetrical with respect to the first diameter.

[0080] In this embodiment, the first diameter may be any diameter of the single crystal furnace 1 .

[0081] In this embodiment, by providing an auxiliary exhaust hood 4, the suction area of ​​the exhaust gas flow can be increased and the suction effect can be improved. Even if there are fewer exhaust holes at the bottom of the single crystal furnace 1, a higher suction efficiency can be guaranteed, thereby improving the adaptability of the exhaust structure to the existing single crystal furnace 1.

[0082] Preferably, in this embodiment, the air inlet channel 31 of the exhaust hood 3 and the auxiliary air inlet channel 41 of the auxiliary exhaust hood 4 extend to the same height, and the air inlet channel 31 and the auxiliary air inlet channel 41 extend to be flush with the bottom of the crucible 7 .

[0083] As shown in Figures 5 to 7, in this embodiment, plug connectors 101 are provided at both ends of the air duct 10, and the plug connectors 101 at both ends of the air duct 10 are respectively plugged into the side walls of the auxiliary exhaust hood body 42 and the exhaust hood body 32. Preferably, in this embodiment, plug slots 34 are respectively provided on the second side walls of the exhaust hood body 32 and the auxiliary exhaust hood body 42, and the shape of the plug slots 34 is adapted to the shape of the plug connectors 101. The plug connectors 101 at both ends of the air duct 10 are respectively plugged into the plug slots 34 on the exhaust hood body 32 and the auxiliary exhaust hood body 42.

[0084] The auxiliary exhaust hood body 42 is connected to the exhaust hood bodies 32 of the two adjacent exhaust hoods 3 through an air duct 10, thereby ensuring the uniformity of the suction force of different exhaust hoods 3 and auxiliary exhaust hoods 4, thereby improving the smoothness of the airflow in the single crystal furnace 1.

[0085] Preferably, in this embodiment, the top and bottom surfaces of the auxiliary exhaust hood body 42, the exhaust hood body 32 and the air duct 10 are respectively on the same horizontal plane, and the upper and lower inner walls of the air duct 10 are respectively flush with the upper and lower inner walls of the exhaust cavity of the exhaust hood body 32 and the auxiliary exhaust hood body 42.

[0086] In this embodiment, the bottom of the single crystal furnace 1 is also provided with electrode holes 12 for installing the heating electrodes of the main heater 5 and the bottom heater 6. The main heater 5 and the bottom heater 6 correspond to two electrode holes 12 respectively. The electrode holes 12 of the main heater 5 and the electrode holes 12 of the bottom heater 6 are staggered with the air inlet channel 31 and the auxiliary air inlet channel 41 to avoid mutual interference between the main heater 5, the bottom heater 6, the exhaust hood 3 and the auxiliary exhaust hood 4.

[0087] In this embodiment, the exhaust hood body 32, the auxiliary exhaust hood body 42, and the air guide pipe 10 are all embedded in the second bottom insulation layer. This can further utilize the temperature of the high-temperature exhaust gas to improve the insulation effect of the bottom insulation layer and reduce energy loss in the single crystal furnace.

[0088] Preferably, the top and bottom surfaces of the auxiliary exhaust hood body 42, the exhaust hood body 32 and the air duct 10 are respectively on the same horizontal plane, and the top and bottom surfaces of the auxiliary exhaust hood body 42, the exhaust hood body 32 and the air duct 10 are respectively in contact with the third bottom insulation layer and the first bottom insulation layer.

[0089] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as above in terms of a preferred embodiment, it is not intended to limit the present invention. Any technician familiar with the present invention can make some changes or modifications to equivalent embodiments using the above-mentioned technical contents without departing from the scope of the technical solution of the present invention. The implementation schemes in the above-mentioned embodiments can be further combined or replaced. However, any simple modifications, equivalent changes and modifications made to the above-mentioned embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the solution of the present invention.

Claims

1. A single crystal furnace, comprising a bottom plate (11) coaxially arranged at the bottom of the single crystal furnace (1), characterized in that: It also comprises an exhaust hood (3) arranged on the inner side of the bottom plate (11), the exhaust channel (33) of which is connected to the exhaust hole provided on the bottom plate (11), and the intake channel (31) of which extends upward along the axial direction of the single crystal furnace (1) and is connected to the furnace chamber (14) of the single crystal furnace (1); the intake channel (31) of the exhaust hood (3) extends to above the bottom heater (6) at the bottom of the single crystal furnace (1).

2. The single crystal furnace according to claim 1, characterized in that: The exhaust hood (3) comprises an exhaust hood body (32), the exhaust hood body (32) comprises side walls, a top wall and a bottom wall which surround each other to form an exhaust cavity, the exhaust hood body (32) is arranged at the bottom of the furnace cavity (14), and the air inlet channel (31) and the air outlet channel (33) of the exhaust hood (3) are both connected to the exhaust cavity and extend from the top and bottom of the exhaust cavity respectively along the axial direction of the single crystal furnace (1) in a direction away from the exhaust cavity.

3. The single crystal furnace according to claim 2, characterized in that: The exhaust hood (3) is provided with a plurality of exhaust holes arranged at intervals around the axis of the furnace cavity (14) and corresponding one-to-one with the exhaust holes on the bottom plate (11); the exhaust cavities of each exhaust hood (3) are connected to the furnace cavity (14) through an air inlet channel (31) and are connected one-to-one with the exhaust holes through an air outlet channel (33); or, The exhaust chamber of the exhaust hood (3) extends along the circumference of the furnace chamber (14), a plurality of air inlet channels (31) are arranged at intervals along the circumference of the furnace chamber (14), and a plurality of air outlet channels (33) are connected to the exhaust holes in a one-to-one correspondence.

4. The single crystal furnace according to claim 3, characterized in that: The auxiliary exhaust hood (4) is arranged on one side of the exhaust hood (3), comprising an auxiliary exhaust hood body (42) and an auxiliary air inlet passage (41) arranged on the top of the auxiliary exhaust hood body (42); the auxiliary exhaust hood body (42) is connected to the exhaust hood body (32) of the exhaust hood (3) through the air guide pipe (10); Preferably, the auxiliary exhaust hood body (42) has the same shape as the exhaust hood body (32), and the auxiliary air inlet passage (41) has the same shape as the air inlet passage (31).

5. The single crystal furnace according to claim 4, characterized in that: The side walls of the exhaust hood body (32) and the auxiliary exhaust hood body (42) include: A first side wall is arranged on a side away from the axis of the single crystal furnace (1) and is in contact with the inner wall of the furnace chamber (14); The second side wall is arranged on a side close to the axis of the single crystal furnace (1), and comprises a plane portion extending radially from both ends of the first side wall toward the direction close to the axis of the single crystal furnace (1), and an arc portion connected between the two plane portions and protruding and extending toward the side close to the axis of the single crystal furnace (1); the two ends of the air guide pipe (10) are respectively connected to the arc portion of the second side wall of the exhaust hood main body (32) and the auxiliary exhaust hood main body (42).

6. The single crystal furnace according to claim 4, characterized in that: The auxiliary exhaust hood (4) is arranged between two adjacent exhaust hoods (3), and the auxiliary exhaust hood body (42) is connected to the exhaust hood bodies (32) of the two adjacent exhaust hoods (3) through an air guide pipe (10).

7. The single crystal furnace according to claim 6, characterized in that: Both ends of the air guide tube (10) are respectively provided with plug connectors (101), and the plug connectors (101) at both ends of the air guide tube (10) are respectively plugged into the second side wall of the auxiliary exhaust hood body (42) and the exhaust hood body (32); The top surface and bottom surface of the auxiliary exhaust hood main body (42), the exhaust hood main body (32) and the air guide pipe (10) are respectively on the same horizontal plane.

8. The single crystal furnace according to any one of claims 4 to 7, characterized in that: A bottom insulation layer (2) is arranged at the bottom of the single crystal furnace (1), and the bottom insulation layer (2) comprises a first bottom insulation layer (21), a second bottom insulation layer (22) and a third bottom insulation layer (23) which are arranged in sequence from bottom to top; The exhaust hood body (32) of the exhaust hood (3) is embedded in the second bottom insulation layer (22) and has a thickness that matches the thickness of the second bottom insulation layer (22). The air inlet channel (31) penetrates the third insulation layer and extends upwards, and the air outlet channel (33) penetrates the first insulation layer and extends downwards.

9. The single crystal furnace according to claim 8, characterized in that: A main thermal insulation layer (13) is arranged on the inner side of the furnace wall of the single crystal furnace (1), and the bottom thermal insulation layer (2) and the main thermal insulation layer (13) surround each other to form a furnace chamber (14) of the single crystal furnace (1); Preferably, a notch adapted to the outer edge of the bottom insulation layer (2) is provided on the inner periphery of the bottom of the main insulation layer (13), and the outer edge of the bottom insulation layer (2) extends into the notch at the bottom of the main insulation layer (13).

10. The single crystal furnace according to claim 8, characterized in that: It also includes a bottom protection pressure plate (9), which is arranged at the bottom of the furnace cavity (14), the outer peripheral wall of the bottom protection pressure plate (9) is in contact with the inner wall of the furnace cavity, and a notch corresponding to the air inlet channel (31) of the exhaust hood (3) is arranged on the outer peripheral wall of the bottom protection pressure plate (9), and the air inlet channel (31) of the exhaust hood (3) is embedded in the notch; Preferably, the bottom protection pressure plate (9) is of a spliced ​​type, comprising a plurality of split plates (91) arranged along the circumference of the single crystal furnace (1).

11. The single crystal furnace according to any one of claims 1 to 7, characterized in that: The air inlet channel (31) of the exhaust hood (3) is arranged to have an arc-shaped cross section along the radial direction of the single crystal furnace (1); The side of the air inlet channel (31) of the exhaust hood (3) away from the axis of the single crystal furnace (1) is in contact with the inner wall of the furnace chamber (14), and the side of the air inlet channel (31) of the exhaust hood (3) close to the axis of the single crystal furnace (1) is parallel to the inner wall of the furnace chamber (14) and spaced apart from the outer edge of the bottom heater (6); Preferably, the left and right sides of the air inlet channel (31) are respectively coplanar with the plane portion on the second side wall of the exhaust hood body (32); The extension length of the plane portion along the radial direction of the single crystal furnace (1) is greater than or equal to the extension length of the left and right sides of the air inlet channel (31) along the radial direction of the single crystal furnace (1).

12. The single crystal furnace according to claim 11, characterized in that: A crucible (7) is arranged in the furnace chamber (14); the distance between the inner wall of the air inlet passage (31) of the exhaust hood (3) on the side close to the axis of the single crystal furnace (1) and the inner wall on the side away from the axis of the single crystal furnace (1) is less than or equal to the gap between the crucible (7) and the inner wall of the furnace chamber (14); Preferably, the extension height of the air inlet channel (31) of the exhaust hood (3) is less than or equal to the bottom height of the crucible (7).

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