Inner guide cylinder for monocrystalline silicon furnace, guide cylinder assembly and monocrystalline silicon furnace

Abstract

The utility model relates to the field of monocrystalline silicon production equipment, in particular to an inner guide cylinder for a monocrystalline silicon furnace, a guide cylinder assembly with the inner guide cylinder and the monocrystalline silicon furnace with the guide cylinder assembly. According to the inner flow guide cylinder for the monocrystalline silicon furnace, a heat dissipation medium containing cavity is formed in a body of the inner flow guide cylinder, and a heat absorption layer is tightly attached to the inner side face of the body of the inner flow guide cylinder. The utility model further provides a guide cylinder assembly for the monocrystalline silicon furnace, the guide cylinder assembly comprises an outer guide cylinder arranged on the outer side and an inner guide cylinder arranged on the inner side, the outer guide cylinder and the inner guide cylinder are installed together, and the inner guide cylinder is as mentioned above. The utility model also provides a monocrystalline silicon furnace, a seed crystal for crystal pulling is arranged in the monocrystalline silicon furnace, and a guide cylinder assembly is sleeved on the outer side of the seed crystal, and the monocrystalline silicon furnace is characterized in that the guide cylinder assembly is described above. On the basis of being convenient to process, the inner guide cylinder also has better capability of absorbing heat radiation, better effect of assisting the cooling of the single crystal silicon rod, shorter cooling time and lower material cost.

Description

Technical Field

[0001] The utility model relates to the field of single crystal silicon production equipment, in particular to an inner guide tube for a single crystal silicon furnace, a guide tube assembly having the inner guide tube, and a single crystal silicon furnace having the guide tube assembly. Background Art

[0002] Single crystal silicon is the base material for most semiconductor components. Currently, most single crystal silicon is produced using the Czochralski method (also known as the J. Czochralski method) in a single crystal silicon furnace (also known as a reduction furnace). Chinese patent document CN110904496A discloses a single crystal silicon furnace, comprising a furnace body, within which is located a quartz crucible 18 for holding raw materials such as polycrystalline silicon blocks. The quartz crucible 18 is mounted within a graphite crucible 15. A heater 14 is provided on the outside of the quartz crucible 18, and a guide tube 2 is provided above it. When pulling a single crystal silicon rod, the heater 14 heats the raw materials in the quartz crucible 18 until they melt. After the melted raw material liquid is regulated to the process temperature, a seed crystal is passed from top to bottom through the guide tube and inserted into the molten raw material liquid. It rotates counterclockwise to the quartz crucible 18 and is lifted upward, causing the raw material liquid to crystallize and solidify into a single crystal silicon rod according to the arrangement order of the silicon atoms in the seed crystal. The seed crystal slowly rises while pulling the single crystal silicon rod solidified on it upward through the guide tube 2. When the single crystal silicon rod of appropriate length is pulled out, the seed crystal stops rotating and the raw material liquid no longer precipitates silicon crystals. After the pulled single crystal silicon rod is cooled, the required single crystal silicon rod is obtained.

[0003] During the production of single-crystal silicon rods, the flow tube regulates the thermal field, assisting in cooling the rods and significantly impacting crystal growth. It's well known that heat transfer occurs in three basic ways: conduction, radiation, and convection. Whenever there's a temperature difference within or between objects, heat energy is transferred from a higher temperature to a lower temperature via one or more of these three methods. Since there's no direct contact between the flow tube and the single-crystal silicon rod to be cooled, heat transfer occurs primarily through radiation. Existing flow tubes are funnel-shaped (an inverted frustum) and typically consist of an outer and inner flow tube. The outer flow tube serves as the outer shell. Because it's located near the crucible or heater, its temperature rises. Therefore, insulation material is placed between the two tubes to prevent heat from transferring to the inner tube, raising its temperature and potentially affecting the cooling of the single-crystal silicon rod. The inner flow tube requires a water cooling system. To facilitate processing, existing inner flow tubes are typically made from easily machined materials, such as high-purity molybdenum. These easily processed materials have a certain ability to absorb thermal radiation. When the single crystal silicon rods continue to emit thermal radiation, the inner guide tubes made of these materials can absorb a portion of the thermal radiation emitted by the single crystal silicon rods and reflect the remaining thermal radiation that cannot be absorbed (most of the reflected thermal radiation returns to the single crystal silicon rods and is absorbed by the single crystal silicon rods). The water cooling device dissipates heat and cools the inner guide tubes that have heated up after absorbing some of the thermal radiation. If such inner guide tubes are made of materials that are easy to process, their ability to absorb thermal radiation is poor, the auxiliary cooling effect of the single crystal silicon rods is not good, and the cooling time required is long. If materials with good thermal radiation absorption are used, it is usually not convenient to drill holes, weld, and other processing, which is not conducive to the layout of water cooling devices. If special materials that are both easy to process and have good thermal radiation absorption are used, the material cost is high. Currently, it is difficult to find a material that is both easy to process and has good thermal radiation absorption ability at a low cost. Utility Model Content

[0004] The technical problem to be solved by the present invention is to provide an inner guide tube, a guide tube assembly having the inner guide tube, and a single crystal silicon furnace having the guide tube assembly, wherein the inner guide tube has a good ability to absorb heat radiation on the basis of being easy to process, has a good effect of assisting the cooling of the single crystal silicon rod, takes a short cooling time, and has a low material cost.

[0005] To solve the above problems, the utility model provides an inner guide tube for a single crystal silicon furnace, wherein a heat dissipation medium accommodating cavity is provided inside the inner guide tube body, and a heat absorbing layer is closely attached to the inner side surface of the inner guide tube body.

[0006] Furthermore, the heat absorption layer is made of metal oxide.

[0007] Furthermore, the heat absorption layer is specifically made of iron oxide and / or zinc oxide and / or copper oxide.

[0008] Furthermore: the side surface of the heat absorption layer away from the inner guide tube body is a rough surface, and / or the thickness of the heat absorption layer is 3 to 50 μm.

[0009] Furthermore, the heat dissipation medium accommodating cavity is a spiral channel for the heat dissipation medium to flow through, and is circumferentially arranged inside the inner guide tube body.

[0010] Furthermore, the heat dissipation medium is included, and the heat dissipation medium is specifically water.

[0011] The utility model also provides a guide tube assembly for a single crystal silicon furnace, comprising an outer guide tube arranged on the outside and an inner guide tube arranged on the inside. The outer guide tube and the inner guide tube are installed together, and the inner guide tube is as described above.

[0012] Furthermore, the outer guide tube and the inner guide tube together form a heat-insulating cavity.

[0013] Furthermore, the heat-insulating cavity is vacuum or filled with heat-insulating material.

[0014] The utility model also provides a single crystal silicon furnace, in which a seed crystal for crystal pulling is installed, and a guide tube assembly is sleeved on the outer side of the seed crystal, characterized in that the guide tube assembly is as described above.

[0015] Beneficial Effects: Since the single crystal silicon rods do not directly contact the inner guide tube, but transfer heat to the inner guide tube mainly through thermal radiation, the heat transfer efficiency is affected by the material's ability to absorb thermal radiation. Since the heat absorption layer only needs to be in close contact with the inner side of the inner guide tube body, there is no need to install a heat dissipation medium, and there is no need to consider too many processing factors. Therefore, the heat absorption layer can be made of a material with a stronger ability to absorb thermal radiation than the inner guide tube. The heat absorption layer can absorb a larger portion of the thermal radiation emitted by the single crystal silicon rod, thereby effectively assisting in cooling the single crystal silicon rod, achieving a better cooling effect and a shorter cooling time. After absorbing thermal radiation, the heat absorption layer heats up. Since the heat absorption layer is in close contact with the inner guide tube body, even if the material of the inner guide tube body has a general ability to absorb thermal radiation, it does not affect the heat absorption layer's direct heat transfer to the inner guide tube body through heat conduction. The heat transferred to the inner guide tube body is dissipated by the heat dissipation medium flowing through it. In this way, the heat absorption layer maintains its own heat at a low level, and can continuously absorb thermal radiation to assist in cooling the single crystal silicon rod. Because the inner guide tube relies on the heat-absorbing layer to absorb thermal radiation, the inner guide tube body can be made with more consideration for processing factors and only needs to be made of materials that are easy to process. In the inner guide tube of the utility model, the heat-absorbing layer only needs to be made of materials with good thermal radiation absorption capabilities, while the inner guide tube body only needs to be made of materials that are easy to process, thereby reducing material costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic diagram of the structure of a single crystal silicon furnace.

[0017] Figure 2 It is a schematic diagram of the structure of the guide tube assembly.

[0018] Figure 3 yes Figure 2 A schematic diagram of the structure after the enlargement of part A.

[0019] Explanation of symbols:

[0020] 1-single crystal silicon furnace; 11-seed crystal; 12-crucible; 13-heating element; 2-flow guide tube assembly; 21-outer flow guide tube; 22-inner flow guide tube; 221-heat dissipation medium accommodating cavity; 222-heat absorption layer; 23-insulating cavity; 3-single crystal silicon rod. DETAILED DESCRIPTION

[0021] The present invention is further described in detail below in conjunction with specific embodiments.

[0022] See Figure 1 The single crystal silicon furnace 1 has a seed crystal 11 installed inside the furnace body for pulling crystals. A guide tube assembly 2 is provided outside the seed crystal 11. A crucible 12 for accommodating raw materials and a heating element 13 for heating the crucible 12 are provided below the guide tube. During operation, the heating element 13 first heats the raw materials in the crucible 12 until they melt. Then the seed crystal 11 passes through the guide tube assembly 2 and extends downward into the crucible 12, while the single crystal silicon solidifies on the seed crystal 11 and moves upward, so that the single crystal silicon can be pulled out. Figure 1 As shown, a single crystal silicon rod 3 is pulled out below it. The structure and working principle of the seed crystal 11, crucible 12 and heating element 13 and the related process of pulling the single crystal silicon rod 3 are all in the existing technology and will not be described in detail here.

[0023] The single crystal silicon rod 3 is pulled by the seed crystal 11 into the guide tube assembly 2 for cooling. Figure 2 , including an outer guide tube 21 arranged on the outside and an inner guide tube 22 arranged on the inside. The outer guide tube 21 and the inner guide tube 22 are welded together at the top and bottom to form a vacuum heat-insulating cavity 23. In this way, although the outer guide tube 21 serves as the outer shell of the guide tube assembly 2, it is close to the crucible 12 (see Figure 1 ) and heating element 13 (see Figure 1 ) and the temperature is higher, but only a small part of the heat is transferred to the inner guide tube 22 by heat conduction. In other embodiments, the heat insulation cavity 23 may not be vacuum, but may be filled with heat insulation materials such as graphite soft felt or graphite cured felt.

[0024] See Figure 3The inner guide tube 22 has a heat dissipation medium chamber 221 formed within it. This chamber 221 is a spiral channel circumferentially arranged within the inner guide tube 22. The single crystal silicon furnace 1 is equipped with a water-cooled radiator (not shown). The cold water outlet of the water-cooled radiator (not shown) is connected to the channel inlet of the heat dissipation medium chamber 221 (not visible due to the angle of the drawing) via a high-temperature resistant water pipe (not shown). The channel outlet of the heat dissipation medium chamber 221 (not visible due to the angle of the drawing) is connected back to the hot water return port of the water-cooled radiator (not shown) via a high-temperature resistant water pipe. The water-cooled radiator supplies cold water to the heat dissipation medium chamber 221 within the inner guide tube 22. The cold water flows through the spiral channel of the heat dissipation medium chamber 221, thereby dissipating heat from the inner guide tube 22. In this embodiment, the heat dissipation medium is water; in other embodiments, the heat dissipation medium can be replaced with silicone oil or a fluorinated liquid. Water-cooled radiators are also conventional technology and will not be described in detail here.

[0025] See Figure 3 The inner side surface of the inner guide tube 22 is plated with a heat absorbing layer 222 having a thickness of 3 to 50 μm. The heat absorbing layer 222 is in close contact with the inner side surface of the inner guide tube 22. Figure 1) does not directly contact the inner guide tube 22, but instead transfers heat to the inner guide tube 22 primarily through thermal radiation. The heat transfer efficiency is affected by the material's ability to absorb thermal radiation. Because the heat absorption layer 222 only needs to be in close contact with the inner surface of the inner guide tube 22 body, there is no need to consider processing factors. Therefore, it can be made of a metal oxide with good thermal radiation absorption capabilities, such as one or more metal oxides such as iron oxide, zinc oxide, and copper oxide. In this way, the heat absorption layer 222 can absorb a large portion of the thermal radiation emitted by the single crystal silicon rod 3. In addition, the inner surface of the heat absorption layer 222, away from the inner guide tube 22 body, is roughened, which can further enhance the thermal radiation absorption effect. The inner guide tube 22, thanks to its heat absorption layer 222, can already absorb a large portion of the thermal radiation emitted by the single crystal silicon rod 3. Therefore, it is sufficient to use a material that is easy to process, such as high-purity molybdenum metal, to manufacture the inner guide tube 22 body. This facilitates welding operations or the processing of spiral channels on the inner guide tube 22 body. After absorbing thermal radiation, the heat-absorbing layer 222 heats up. Because the heat-absorbing layer 222 is in close contact with the inner guide tube 22 body, even if the material making up the inner guide tube 22 body is not very good at absorbing thermal radiation, this does not affect the heat-absorbing layer 222's direct heat transfer to the inner guide tube 22 body via heat conduction. The heat transferred to the inner guide tube 22 body is dissipated by the cold water flowing through the inner guide tube 22 body. In this way, the heat-absorbing layer 222 maintains its own heat at a low level, continuously absorbing thermal radiation, assisting in cooling the single crystal silicon rods 3 and shortening the cooling time required for the single crystal silicon rods 3. The heat-absorbing layer 222 only needs to be made of a material with good thermal radiation absorption, while the inner guide tube 22 body only needs to be made of a material that is easy to process. Neither needs to use special materials that are both easy to process and have good thermal radiation absorption capabilities, resulting in lower material costs.

[0026] The above is only an embodiment of the present invention and does not limit the scope of patent protection. Those skilled in the art can make non-substantial changes or substitutions based on the present invention and still fall within the scope of patent protection.

Claims

1. The inner guide tube used for a single crystal silicon furnace has a heat dissipation medium accommodating cavity inside the body, and is characterized by: A heat-absorbing layer is tightly attached to the inner side surface of the inner guide tube body; the side of the heat-absorbing layer away from the inner guide tube body is a rough surface, and / or the thickness of the heat-absorbing layer is 3 to 50 μm; the heat dissipation medium accommodating cavity is a spiral channel for the heat dissipation medium to flow through, and is circumferentially arranged inside the inner guide tube body; including the heat dissipation medium, the heat dissipation medium is specifically water.

2. The inner guide tube according to claim 1, wherein: The heat absorption layer is made of metal oxide.

3. A guide tube assembly for a single crystal silicon furnace, comprising an outer guide tube arranged on the outside and an inner guide tube arranged on the inside, wherein the outer guide tube and the inner guide tube are installed together, characterized in that: The inner guide tube is as described in claim 1 or 2.

4. The guide tube assembly according to claim 3, wherein: The outer guide tube and the inner guide tube together form a heat-insulating cavity.

5. The guide tube assembly according to claim 4, characterized in that: The heat-insulating cavity is vacuum or filled with heat-insulating material.

6. A single crystal silicon furnace, wherein a seed crystal for crystal pulling is installed inside, and a guide tube assembly is provided outside the seed crystal, characterized in that: The guide tube assembly is as described in any one of claims 3 to 5.

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