High-purity silicon carbide synthesis process based on argon glove box and double-station furnace

Abstract

The application relates to the technical field of silicon crystal synthesis, and discloses a high-purity silicon carbide synthesis process based on an argon glove box and a double-station furnace, which comprises the following steps: a silicon carbide raw material synthesis chamber is used to place a raw material synthesis crucible on a crucible tray of the silicon carbide raw material synthesis chamber through a transition chamber one; after the crucible is lifted to a predetermined position, a raw material synthesis process is performed; during the raw material synthesis, a newly loaded crucible is placed in a transition chamber two to be pre-evacuated. In the application, the argon glove box double-station furnace improves the product performance and stability, integrates the silicon carbide raw material synthesis chamber and a silicon carbide crystal growth chamber into a double-station furnace body, matches the argon glove box of the transition chamber one and the transition chamber two, performs material transmission in an argon environment all the time, avoids contact with external air, eliminates nitrogen and metal impurity pollution, effectively guarantees the purity of raw materials and single crystals, and further guarantees the product quality stability.

Description

Technical Field

[0001] This invention relates to the field of silicon crystal synthesis technology, and in particular to a high-purity silicon carbide synthesis process based on an argon glove box and a dual-station furnace. Background Technology

[0002] The dual-station glovebox silicon carbide crystal growth furnace is a core piece of equipment for silicon carbide single crystal preparation, integrating a dual-station parallel growth unit, a glovebox-isolated operating environment, and ultra-high purity atmosphere control technology. It primarily employs the physical vapor transport method to grow high-purity semi-insulating or conductive silicon carbide crystals. The dual-station design allows for simultaneous operation of two independent growth chambers, significantly improving production efficiency and reducing unit costs. Independent temperature and pressure control is available between the stations to adapt to different process requirements. The integrated glovebox ensures that loading and crystal removal are performed under an inert gas (argon) atmosphere, isolating oxygen, moisture, and other impurities to prevent crystal contamination. Ultra-high purity is guaranteed with a vacuum level of ≤5×10⁻⁻⁻⁻⁵. 5 Equipped with high-purity graphite components and a precision gas purification system, Pa ensures crystal purity of 6N or higher. This growth furnace is widely used in the third-generation semiconductor industry, providing high-quality substrate materials for high-performance silicon carbide power devices required in fields such as new energy vehicles, 5G communications, and aerospace.

[0003] Currently, most silicon carbide raw material synthesis and crystal growth furnaces widely used in the industry are single-unit stainless steel chambers or quartz tubes. With the increasing demand for ultra-high purity raw materials and ultra-high purity single crystals in the semiconductor industry, single-unit equipment lacks breakthroughs in key performance indicators such as nitrogen control and impurity content control, making it difficult to meet the purity requirements of raw materials for ultra-high purity silicon carbide production. Existing processes require ultra-long vacuuming, hydrogen addition, or doping to control nitrogen content, significantly increasing production cycles and costs, or sacrificing production efficiency and reducing product quality. At the same time, existing processes have stringent requirements for the production environment, leading to increased investment in factory construction. Furthermore, product quality stability is easily affected by management level, causing quality fluctuations and performance instability. Frequent process adjustments also hinder the formation of stable standard production processes in the industry, delaying the process-oriented and large-scale development of the silicon carbide raw material industry. In actual production, silicon carbide crystal growth and raw material preparation are often carried out separately, resulting in more interference during material transfer and the need for pre-treatment before loading into the furnace, which invisibly extends the production cycle, leads to poor stability, and makes it difficult to achieve the ideal level of cleanliness.

[0004] To address the aforementioned issues, a high-purity silicon carbide synthesis process based on an argon glove box and a dual-station furnace is proposed. Summary of the Invention

[0005] To overcome the above shortcomings, this invention provides a high-purity silicon carbide synthesis process based on an argon glove box dual-station furnace. It aims to improve the existing silicon carbide raw material synthesis and crystal growth processes, which mostly use single-unit equipment, have insufficient nitrogen and impurity control capabilities, increase costs and time consumption or reduce quality, and have high requirements for the production environment, poor quality stability, separate raw material preparation and crystal growth, many material transfer interferences, require pretreatment, have long cycles and insufficient cleanliness, thus hindering the large-scale development of the industry.

[0006] To achieve the above objectives, the present invention employs the following technical solution: a high-purity silicon carbide synthesis process based on an argon glove box, comprising the following steps:

[0007] S1: The silicon carbide raw material synthesis chamber places the raw material synthesis crucible on the crucible tray of the silicon carbide raw material synthesis chamber through the transition chamber. After the crucible rises to the predetermined position, the raw material synthesis process is executed.

[0008] S2: In the first transition chamber, during the raw material synthesis process, the newly loaded crucible is placed in the second transition chamber for pre-vacuuming.

[0009] S3: In the silicon carbide crystal growth chamber one, after the raw material synthesis is completed, the synthesized crucible is taken out and the newly loaded crucible in the transition chamber two is placed into the silicon carbide raw material synthesis chamber to continue the raw material synthesis process.

[0010] S4: In the second transition chamber, the silicon carbide crystal growth process is carried out through the first silicon carbide crystal growth chamber, and the silicon carbide crystal growth is consistent with the raw material synthesis.

[0011] S5: Both the silicon carbide raw material synthesis chamber and the silicon carbide crystal growth chamber are equipped with heating systems, and the heating systems adopt induction heating.

[0012] As a further description of the above technical solution:

[0013] The argon purity of the transition chamber 1 and transition chamber 2 is ≤9N and the water oxygen content is ≤6N. The vacuum port of the high vacuum system is connected to the lower furnace chamber through a slide valve. The vacuum gauge measurement interface is located on the top of the inner wall of the upper furnace chamber. The furnace body and pipelines are equipped with shut-off valves. The high vacuum system has two pumping speeds and two pumping methods: pumping with a filter and pumping without a filter.

[0014] As a further description of the above technical solution:

[0015] The upper furnace chamber cover is a double-layer water-cooled structure, and the upper furnace chamber is a cylindrical vertical double-layer water-cooled structure. The outer wall of the upper furnace chamber cover and the flange are argon arc welded. The interface of the upper furnace chamber cover is sealed with a metal gasket and a fluororubber ring. An infrared thermometer interface is provided on the upper furnace chamber cover.

[0016] As a further description of the above technical solution:

[0017] The base is divided into upper and lower frames. The upper frame is made of high-quality stainless steel and the lower frame is made of high-quality carbon steel. The second silicon carbide crystal growth chamber is a vertical double-layer water-cooled structure with quartz tubes. The interface of the second silicon carbide crystal growth chamber is sealed with fluororubber rings.

[0018] As a further description of the above technical solution:

[0019] The dual-station furnace is equipped with a crucible lifting and discharging assembly, which is externally connected to a linear unit for bottom discharge.

[0020] As a further description of the above technical solution:

[0021] The interior of the second silicon carbide crystal growth chamber is a quartz tube, and the first silicon carbide crystal growth chamber and the silicon carbide raw material synthesis chamber are symmetrically distributed on the top of the base.

[0022] As a further description of the above technical solution:

[0023] The upper furnace chamber, lower furnace chamber, pipelines, and shut-off valves work together to achieve individual vacuuming. The high vacuum system's fast evacuation mode corresponds to two evacuation methods: evacuation with a filter and evacuation without a filter.

[0024] As a further description of the above technical solution:

[0025] A silicon carbide raw material synthesis chamber is provided, with a heating system fixedly connected to its outer side. An upper furnace chamber cover is installed on the top of the chamber, and an upper furnace chamber is installed at the bottom of the inner wall of the upper furnace chamber cover. A base is installed at the bottom of the chamber, and a lower furnace chamber is installed at the bottom of the base. A crucible lifting and unloading assembly is installed on the inner wall of the lower furnace chamber. A silicon carbide crystal growth chamber one is installed on the top right side of the base, and a silicon carbide crystal growth chamber two is fixedly connected to its outer side. A high vacuum system is installed on the top of the inner wall of the silicon carbide raw material synthesis chamber. A transition chamber one is installed on the left side of the lower furnace chamber, and a transition chamber two is installed on the right side of the lower furnace chamber.

[0026] As a further description of the above technical solution:

[0027] The first and second transition chambers are dual-station argon glove boxes, and the first and second transition chambers are symmetrically distributed on the left and right sides of the crucible lifting and discharging assembly.

[0028] As a further description of the above technical solution:

[0029] One end of the high vacuum system penetrates the base and connects to the inner wall of the crucible lifting and discharging assembly, while the other end of the high vacuum system penetrates the upper furnace cover and connects to the inner wall of the silicon carbide raw material synthesis chamber.

[0030] The present invention has the following beneficial effects:

[0031] 1. In this invention, the argon glove box dual-station furnace improves product performance and stability. It integrates the silicon carbide raw material synthesis chamber and the silicon carbide crystal growth chamber into a dual-station furnace body, and is equipped with argon glove boxes for transition chamber one and transition chamber two. The material transfer is carried out in an argon environment throughout the process, avoiding contact with the outside air and eliminating contamination from nitrogen and metal impurities. This effectively ensures the purity of raw materials and single crystals. The furnace cavity and hot zone components do not come into contact with the external environment during furnace opening, further ensuring the stability of product quality.

[0032] 2. In this invention, the dual-station design improves the production efficiency of silicon carbide during the raw material synthesis process. The pre-vacuuming of the newly loaded crucible can be completed through another transition chamber, ensuring uninterrupted process connection, greatly improving equipment utilization efficiency, eliminating the need for pre-treatment of materials before loading into the furnace, simplifying process steps, shortening the production cycle, and promoting the process-oriented and large-scale development of the silicon carbide raw material industry.

[0033] 3. In this invention, the argon glove box dual-station furnace for synthesizing silicon carbide reduces the overall cost. The argon glove box provides a stable inert gas environment, reducing material loss caused by contact with air, reducing material consumption costs, eliminating the need for pretreatment steps, reducing corresponding energy consumption expenditures, eliminating the need to invest heavily in building a special production environment to meet process requirements, and reducing the frequency of process adjustments, thereby reducing additional costs caused by quality fluctuations. Attached Figure Description

[0034] Figure 1 This is a perspective view of the high-purity silicon carbide synthesis process based on an argon glove box and the dual-station furnace proposed in this invention.

[0035] Figure 2 This is a front view of the high-purity silicon carbide synthesis process based on an argon glove box and the dual-station furnace proposed in this invention.

[0036] Figure 3 The flowchart shows the high-purity silicon carbide synthesis process based on an argon glove box and the dual-station furnace proposed in this invention.

[0037] Figure 4 This is a flow chart of the high-purity silicon carbide synthesis process based on an argon glove box and the transition chamber of a dual-station furnace proposed in this invention.

[0038] Figure 5 This is a flow chart of the high-purity silicon carbide synthesis process based on an argon glove box and the transition chamber of a dual-station furnace proposed in this invention.

[0039] Legend:

[0040] 1. Silicon carbide raw material synthesis chamber; 2. Transition chamber one; 3. Silicon carbide crystal growth chamber one; 4. Transition chamber two; 5. High vacuum system; 6. Upper furnace chamber cover; 7. Heating system; 8. Base; 9. Silicon carbide crystal growth chamber two; 10. Crucible lifting and unloading assembly; 11. Upper furnace chamber; 12. Lower furnace chamber. Detailed Implementation

[0041] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0042] Reference Figure 1-3 The first embodiment of the present invention provides a high-purity silicon carbide synthesis process based on an argon glove box dual-station furnace, comprising the following steps:

[0043] S1: The silicon carbide raw material synthesis chamber 1 places the raw material synthesis crucible on the crucible tray of the silicon carbide raw material synthesis chamber 1 through the transition chamber 2. After the crucible rises to the predetermined position, the raw material synthesis is performed.

[0044] S2: During the raw material synthesis in transition chamber 1, the newly loaded crucible is placed in transition chamber 2 for pre-vacuuming;

[0045] S3: After the raw material synthesis in silicon carbide crystal growth chamber 13 is completed, the synthesized crucible is removed and the newly loaded crucible in transition chamber 24 is placed into silicon carbide raw material synthesis chamber 1 to continue the raw material synthesis process.

[0046] S4: Silicon carbide crystal growth in transition chamber 24 is performed through silicon carbide crystal growth chamber 13, and the silicon carbide crystal growth is consistent with the raw material synthesis;

[0047] S5: Both the silicon carbide raw material synthesis chamber 1 and the silicon carbide crystal growth chamber 3 are equipped with a heating system 7. The heating system 7 adopts induction heating to heat the crucible inside the furnace. This design is to avoid material exposure to air and eliminate nitrogen and metal impurity contamination through parallel operation of two workstations, thereby greatly improving production efficiency and solving the problems of long cycle and insufficient purity in traditional processes.

[0048] The argon purity inside transition chamber 1 (2) and transition chamber 2 (4) is ≤9N, and the water and oxygen content is ≤6N. The vacuum port of the high vacuum system 5 is connected to the lower furnace chamber 12 via a gate valve to achieve the connection and disconnection between the vacuum system and the furnace body. The vacuum gauge measurement interface is located in the upper furnace chamber 11. The furnace body and pipelines are equipped with shut-off valves. The evacuation speed of the high vacuum system 5 is divided into fast evacuation and slow evacuation, and the evacuation method includes evacuation with a filter and evacuation without a filter. This design is to strictly control the argon purity inside transition chamber 1 (2) and transition chamber 2 (4) to ≤9N and the water and oxygen content to ≤6N, creating an ultra-high purity inert atmosphere and blocking oxygen from the source. To prevent moisture contamination of materials, the vacuum port of the high vacuum system 5 is connected to the lower furnace chamber 12 via a slide gate valve, allowing for rapid switching between the vacuum system and the furnace body. The vacuum gauge measurement interface is located in the upper furnace chamber 11, enabling real-time monitoring of the vacuum level to ensure compliance. The furnace body and pipelines are equipped with shut-off valves to ensure reliable sealing of the gas circuit. The high vacuum system 5's fast pumping mode can quickly reduce the chamber pressure and shorten the pretreatment time, while the slow pumping mode provides precise purification. Both pumping methods, with or without filters, are adapted to different material cleanliness requirements, avoiding the introduction of impurities and flexibly adapting to production scenarios, significantly reducing the risk of raw material and crystal contamination.

[0049] The upper furnace chamber cover 6 is a double-layer water-cooled structure, and the upper furnace chamber 11 is a cylindrical vertical double-layer water-cooled structure. The outer wall of the upper furnace chamber cover 6 and the flange are argon-arc welded. The interface of the upper furnace chamber cover 6 is sealed with a metal gasket and a fluororubber ring. An infrared thermometer interface is provided on the upper furnace chamber cover 6. This design is to allow the upper furnace chamber cover 6 to adopt a double-layer water-cooled structure, which can efficiently dissipate the heat generated during the heating process and avoid excessive temperature in the cavity, which may cause changes in material properties. The upper furnace chamber 11 is a cylindrical vertical double-layer water-cooled structure, which ensures uniform temperature throughout the cavity and provides a stable temperature field for the synthesis and growth process. The outer wall of the upper furnace chamber cover 6 and the flange are argon-arc welded with no gaps. Combined with the double sealing design of the metal gasket and the fluororubber ring, it completely blocks the infiltration of external air and prevents contaminants from entering the furnace body. The infrared thermometer interface on the upper furnace chamber cover 6 provides real-time feedback on the temperature inside the cavity, which facilitates precise control of heating parameters, further improves the consistency of product quality, and solves the quality fluctuation problems caused by poor sealing and inaccurate temperature measurement in traditional equipment.

[0050] The base 8 is divided into upper and lower frames. The upper frame is welded from high-quality stainless steel, and the lower frame is welded from high-quality carbon steel. The silicon carbide crystal growth chamber 2 (9) is a vertical double-layer water-cooled structure with quartz tubes. The interfaces of the silicon carbide crystal growth chamber 2 (9) are sealed with fluororubber rings. This design is to ensure the structural strength of the base 8 and to stably support the entire furnace body. The upper water-cooled frame is made of high-quality stainless steel, which is corrosion-resistant, does not leach impurities, avoids contamination of the furnace environment, and has good thermal conductivity to aid in heat dissipation. The lower frame is welded from high-quality carbon steel to ensure the structural strength of the base and to stably support the entire furnace body. The silicon carbide crystal growth chamber 2 (9) is a vertical double-layer water-cooled structure with quartz tubes. Quartz tubes have strong chemical stability, do not react with materials, and are resistant to high temperatures, making them suitable for the high-temperature environment of crystal growth. Its interfaces are sealed with fluororubber rings, providing excellent sealing performance and preventing air leakage from the chamber. The double-layer water-cooled structure balances the stability, corrosion resistance, and sealing of the growth furnace, reduces the risk of contamination from structural components, extends the service life of the growth furnace, reduces maintenance costs, and facilitates large-scale production in the industry.

[0051] The dual-station furnace is equipped with a crucible lifting and discharging assembly 10, which is externally connected to a linear unit to achieve bottom discharge. This design allows the crucible lifting and discharging assembly 10 in the dual-station furnace to be connected to a high-precision linear unit for bottom discharge. The linear unit operates smoothly and can precisely control the lifting and movement of the crucible, avoiding collisions with the furnace body or spillage of materials during transfer, thus reducing material loss and impurity generation. The bottom discharge design eliminates the need to open the upper furnace chamber cover 6, preventing the thermal components inside the furnace from contacting the outside air and eliminating nitrogen and moisture contamination. At the same time, it facilitates integration into automated production lines, reduces manual intervention, and improves production efficiency. The crucible lifting and discharging assembly 10 effectively solves the problems of high contamination risk and cumbersome operation of traditional discharge methods, ensuring product purity and production continuity, and reducing labor costs.

[0052] The silicon carbide crystal growth chamber 13 is equipped with a silicon carbide crystal growth chamber 29, which contains a quartz tube. The silicon carbide crystal growth chamber 13 and the silicon carbide raw material synthesis chamber 1 are symmetrically distributed on the top of the base 8. This design is to ensure that the silicon carbide crystal growth chamber 13 and the silicon carbide raw material synthesis chamber 29 contain high-purity quartz tubes. Quartz tubes have good light transmittance and extremely low impurity content, providing a clean and stable cavity environment for crystal growth and avoiding secondary contamination. The symmetrical distribution of the silicon carbide crystal growth chamber 13 and the silicon carbide raw material synthesis chamber 1 on the top of the base 8 makes the gas circuit and heat field distribution of the two chambers more uniform, ensuring the consistency of process parameters in the dual-station process. At the same time, it shortens the material transmission path between the two chambers, reduces material exposure time, and reduces the risk of contamination. The symmetrical design also facilitates the optimization of the overall equipment layout, saves factory space, improves the ease of equipment operation, and promotes the process-oriented and large-scale development of silicon carbide production.

[0053] The upper furnace chamber 11, lower furnace chamber 12, pipelines, and shut-off valves work together to achieve individual vacuuming. The high vacuum system 5 has two pumping modes: one with a filter and one without. The slow pumping mode also has two pumping modes: one with a filter and one without. This design allows for individual vacuuming of each chamber without overall vacuuming, saving energy and allowing for flexible adjustment of the vacuum level of each chamber according to the needs of different process stages, thus improving process adaptability. The high vacuum system 5's fast pumping mode has two pumping methods: one with a filter to filter out small particles in the gas, suitable for vacuum treatment after initial loading, and one without a filter to improve pumping efficiency, suitable for chambers with higher cleanliness. The two pumping methods in the slow pumping mode can precisely control the vacuum gradient, avoiding sudden pressure drops that would prevent impurities adsorbed on the material surface from being completely desorbed. The pumping methods balance efficiency and cleanliness, reduce production energy consumption, ensure vacuum requirements for different process stages, and further improve product purity and process stability.

[0054] Reference Figure 1-3 The second embodiment of the present invention provides a dual-station furnace for high-purity silicon carbide synthesis. The furnace includes a silicon carbide raw material synthesis chamber 1, with a heating system 7 fixedly connected to its outer side. An upper furnace chamber cover 6 is installed on the top of the silicon carbide raw material synthesis chamber 1, and an upper furnace chamber 11 is installed at the bottom of the inner wall of the upper furnace chamber cover 6. A base 8 is installed at the bottom of the silicon carbide raw material synthesis chamber 1, and a lower furnace chamber 12 is installed at the bottom of the base 8. A crucible lifting and unloading assembly 10 is provided on the inner wall of the lower furnace chamber 12. A silicon carbide crystal growth chamber 1-3 is installed on the top right side of the base 8, and a silicon carbide crystal growth chamber 2-9 is fixedly connected to its outer side. A high vacuum system 5 is installed on the top of the inner wall of the silicon carbide raw material synthesis chamber 1. A transition chamber 1-2 is installed on the left side of the lower furnace chamber 12, and a transition chamber 2-4 is installed on the right side of the lower furnace chamber 12. This design is for implementing the dual-station furnace of this synthesis process. The system includes a silicon carbide raw material synthesis chamber 1, a heating system 7 fixed on the outside of the silicon carbide raw material synthesis chamber 1 to provide a stable heat source for raw material synthesis, an upper furnace chamber cover 6 installed on the top of the silicon carbide raw material synthesis chamber 1 to form a sealed cavity with the upper furnace chamber 11, a base 8 at the bottom to ensure the overall stability of the growth furnace, a crucible lifting and discharging component 10 provided on the inner wall of the lower furnace chamber 12 at the bottom of the base 8 to achieve precise transfer of the crucible, a silicon carbide crystal growth chamber 1 3 connected to the outside of the silicon carbide crystal growth chamber 2 9 on the top right of the base 8 to achieve crystal growth function; a high vacuum system 5 on the top of the inner wall of the silicon carbide raw material synthesis chamber 1 to ensure the vacuum environment of the cavity, and transition chamber 1 2 and transition chamber 2 4 on the left and right sides of the lower furnace chamber 12 to achieve pollution-free material transfer. The growth furnace structure integrates raw material synthesis and crystal growth functions, is sealed throughout to isolate pollution, greatly improves production efficiency and product purity, reduces equipment space occupation, and is suitable for the needs of large-scale industrial production.

[0055] Transition chamber 1 (2) and transition chamber 2 (4) are dual-station argon glove boxes, symmetrically distributed on the left and right sides of the crucible lifting and discharging assembly 10. This design ensures the shortest material transfer path and improves the efficiency of dual-station collaboration. The argon glove boxes continuously provide an inert environment with argon purity ≤9N and water / oxygen content ≤6N, preventing materials from contacting air during transfer and preventing oxidation and impurity adsorption. The isolated operation design of the glove boxes eliminates the need for operators to directly contact materials, reducing human contamination. Crucible positioning adjustments can also be made within the glove boxes to ensure transfer accuracy, completely blocking contamination paths during transfer. This streamlines the raw material synthesis and crystal growth process, significantly improving production efficiency and solving the problems of excessive material transfer interference and insufficient cleanliness in traditional equipment.

[0056] One end of the high vacuum system 5 penetrates the base 8 and connects to the inner wall of the crucible lifting and discharging assembly 10, while the other end of the high vacuum system 5 penetrates the upper furnace cover 6 and connects to the inner wall of the silicon carbide raw material synthesis chamber 1. This design allows the high vacuum system 5 to penetrate the base 8 and connect to the inner wall of the crucible lifting and discharging assembly 10, enabling vacuum treatment of the crucible lifting path and preventing residual air or impurities from contaminating the crucible and materials. The other end penetrates the upper furnace cover 6 and connects to the inner wall of the silicon carbide raw material synthesis chamber 1, allowing direct vacuuming of the synthesis chamber. This ensures that the chamber vacuum level reaches the required standard quickly and is evenly distributed. The dual-interface design allows the high vacuum system 5 to simultaneously or separately vacuum the transfer path and the synthesis chamber, improving vacuum treatment efficiency, ensuring the consistency of the vacuum environment throughout the process, and precisely controlling the vacuum level. This avoids uneven vacuum gradients caused by a single interface, reduces product quality fluctuations due to differences in the vacuum environment, and further ensures the purity and performance stability of high-purity silicon carbide.

[0057] Working principle: After the growth furnace is started, it enters the initialization stage. The control system simultaneously starts the argon supply system and the high vacuum system 5, introducing high-purity argon into the silicon carbide raw material synthesis chamber 1, silicon carbide crystal growth chamber 3, transition chamber 2, and transition chamber 4. The environmental parameters of each chamber are monitored in real time through the vacuum gauge measurement interface of the upper furnace chamber 11 until the argon purity is ≤9N and the water and oxygen content is ≤6N, thus establishing a stable inert atmosphere. Subsequently, the high vacuum system 5 connects to the filter through the gate valve and uses a fast evacuation mode to evacuate the silicon carbide raw material synthesis chamber 1 and silicon carbide crystal growth chamber 3 until the vacuum degree approaches 5×10⁻ 5 At Pa, switch to slow pumping mode for refined purification, ultimately stabilizing the vacuum level of each core cavity at ≤5×10⁻ 5Pa, during this process, the double-layer water-cooled structure of the upper furnace chamber cover 6 and the upper furnace chamber 11 is activated, and the residual heat of the cavity is discharged through circulating cooling water to avoid high temperature affecting the material properties. The external linear unit of the crucible lifting and discharging assembly 10 performs self-inspection, so that the lifting and moving accuracy meets the standard and prepares for subsequent material transfer.

[0058] After initialization, the coordinated operation of the dual-station argon glove box is key to improving efficiency and reducing pollution. For raw material feeding and transfer inside transition chamber 2, the isolation door between transition chamber 2 and the outside is opened. Operators operate through the glove box isolation mechanism, placing the raw material synthesis crucible stably on the support platform inside transition chamber 2. The isolation door is closed, and the built-in argon replenishment device is activated to maintain the argon purity and water / oxygen content within the chamber. Simultaneously, the pressure balance between transition chamber 2 and lower furnace chamber 12 is adjusted through the shut-off valve on the pipeline to prevent outside air infiltration due to pressure difference. After confirming that the vacuum level of silicon carbide raw material synthesis chamber 1 meets the standard, the channel valve between transition chamber 2 and silicon carbide raw material synthesis chamber 1 is opened, and the crucible lifting and unloading assembly 10 is activated to precisely transfer the crucible to the crucible tray in silicon carbide raw material synthesis chamber 1 at a uniform speed. After the transfer is completed, the channel valve is immediately closed to maintain an inert atmosphere inside transition chamber 2.

[0059] The recycling and reuse of silicon carbide finished products: After the raw material synthesis process in silicon carbide raw material synthesis chamber 1 is completed, the crucible lifting and unloading assembly 10 is activated to lower the synthesized silicon carbide raw material crucible to a position accessible in transition chamber 2. The channel valve is opened, and the finished product crucible is removed through the glove box. If continuous production is required, the feeding operation in step 1 can be repeated to achieve uninterrupted transfer. If immediate feeding is not required, the channel valve is closed to maintain the standby environment of transition chamber 2, so that gas replacement is not required for the next use. Transition chamber 2 is one of the core transfer cavities of the dual-station furnace. It is installed on the left side of the lower furnace chamber 12 and symmetrically distributed on the left side of the crucible lifting and unloading assembly 10. It is a sealed argon-cooled furnace. The gas glove box structure ensures that the argon purity in the lower furnace chamber 12 is strictly controlled to ≤9N and the water and oxygen content to ≤6N. It is equipped with an independent argon replenishment device and a simple filtration system to stabilize the inert environment. The transition chamber 2 mainly serves the dual functions of raw material feeding and finished product recovery. During feeding, the crucible of the raw material to be synthesized is sent in through the glove box isolation operation. After pressure balancing, it is transferred to the silicon carbide raw material synthesis chamber 1. During discharging, the synthesized crucible is received and removed to avoid direct exposure of the material to the outside air. This achieves pollution-free transfer of the material between the outside and the synthesis chamber, reduces contact with impurities such as nitrogen and oxygen, and ensures the initial purity of the raw material. At the same time, the dual-station design improves the smoothness of process connection.

[0060] Parallel pretreatment is performed inside transition chamber 2 (4). During the raw material synthesis process in silicon carbide raw material synthesis chamber 1, the isolation door between transition chamber 2 (4) and the outside is opened. The newly loaded crucible is placed into the internal support platform through the glove box. After closing the isolation door, argon gas is added to maintain the chamber environment up to standard. Then, the high vacuum system 5 is started and connected to transition chamber 2 (4) through the gate valve. Pre-vacuuming is performed using a process of fast evacuation through the filter followed by slow evacuation through the filter. The vacuum level is monitored in real time by a vacuum gauge until the vacuum level inside the chamber is ≤5×10⁻. 5 Pa, this process can deeply remove air, moisture and volatile pollutants in the crucible, reduce the impurity load of subsequent synthesis processes, eliminate the need for additional pretreatment of materials before loading into the furnace, and shorten the production cycle.

[0061] After rapid connection and circulation, and pre-vacuuming, transition chamber 2 (4) is in standby mode, with the channel valve remaining closed to maintain a vacuum and slightly positive pressure environment of inert gas in the chamber. When the current batch of raw materials in silicon carbide raw material synthesis chamber 1 is synthesized and removed via transition chamber 2, the control system immediately opens the channel valve between transition chamber 2 (4) and silicon carbide raw material synthesis chamber 1. The pressure in both chambers is quickly balanced via the shut-off valve, and the crucible lifting and unloading assembly 10 is activated to transfer the pre-treated new-load crucible to the crucible tray in silicon carbide raw material synthesis chamber 1. After the new-load crucible transfer is complete, the transition chamber... Step 24 immediately repeats the operation of step 1 to prepare a pre-vacuum crucible for the next batch of processes, significantly improving equipment operating efficiency. Transition chamber 24 and transition chamber 12 are symmetrically installed on the right side of the lower furnace chamber 12. Both are sealed argon glove boxes with the same internal environmental parameters as transition chamber 12: argon purity ≤9N and water / oxygen content ≤6N. They are directly connected to the high vacuum system 5 through a gate valve. When the current batch of synthesis process is executed in the silicon carbide raw material synthesis chamber 1, a new charging crucible is received simultaneously, and the high vacuum system 5 is started to complete the pre-vacuum process according to the fast and slow evacuation procedures, with a vacuum degree ≤5×10⁻. 5 Pa removes air and volatile impurities from the crucible in advance. After the previous batch of processes is completed, the pretreated crucible can be quickly transferred to the synthesis chamber, achieving seamless process connection, significantly shortening the batch interval time, improving equipment utilization, and at the same time, the pretreatment process further reduces the risk of material contamination and ensures the purity and stability of the product.

[0062] During the raw material synthesis stage, after the crucible in the silicon carbide raw material synthesis chamber 1 is in place, all channel valves are closed. The high vacuum system 5 reconfirms that the vacuum level of the chamber meets the standard. Then, a small amount of high-purity argon is added as a protective gas through the interface of the upper furnace cover 6. The heating system 7 is started, and induction heating is used to generate eddy currents in the crucible through electromagnetic induction. The temperature is raised to the synthesis temperature according to the preset temperature curve. At this temperature, silicon powder and carbon powder react to generate silicon carbide. At the same time, the raw materials are purified and densified through physical gas phase transport. The infrared thermometer on the upper furnace cover 6 monitors the chamber temperature in real time. If the temperature exceeds the threshold, the double-layer water cooling structure automatically increases the cooling water flow to ensure that the temperature is stable within the process range and to avoid uneven product quality caused by temperature fluctuations.

[0063] During the crystal growth stage, after the raw material synthesis is completed, the crucible lifting and unloading assembly 10 is activated to transfer the crucible containing silicon carbide raw materials to the crucible tray inside the silicon carbide crystal growth chamber 3 through an argon glove box. The channel valve is closed, and the argon purity, water and oxygen content, and vacuum degree of the silicon carbide crystal growth chamber 3 are adjusted according to the initialization stage standards. The heating system 7 is activated, and the temperature is controlled to the heating temperature using the induction heating method consistent with the raw material synthesis process. The temperature gradient is maintained so that the silicon carbide raw materials are sublimated and deposited on the seed crystal to form high-purity silicon carbide crystals. The quartz tube cavity of the silicon carbide crystal growth chamber 9 provides a clean and stable environment for crystal growth. The double-layer water-cooling structure ensures uniform cavity temperature, and the fluororubber ring seal prevents impurities from penetrating, ensuring the purity and stability of the crystal growth process.

[0064] After the production process is completed, the equipment reset stage begins: the heating system 7 and the argon supply system are shut down. After the temperature in the silicon carbide crystal growth chamber 3 drops to room temperature, the crucible with the high-purity silicon carbide crystal is lowered to the transition chamber 2 or the transition chamber 4 via the crucible lifting and unloading assembly 10. The finished product is removed through the glove box. The cleaning procedure is started, and each chamber, pipe and crucible lifting and unloading assembly 10 are purged with inert gas to remove residual material dust. The double sealing structure of the upper furnace cover 6 and the fluororubber ring seal of the transition chamber are checked for integrity. Argon is added to the standby pressure of each chamber to a slightly positive pressure. The high vacuum system 5 is shut down, and the crucible lifting and unloading assembly 10 is reset to the initial position, completing a single production cycle.

[0065] The parallel operation of the dual-station transition chamber allows raw material synthesis and new material pretreatment to be carried out simultaneously, significantly shortening batch intervals and improving production efficiency. The precise control of the high vacuum system 5 and the inert atmosphere of the argon glove box block contamination from air, moisture, and external impurities at the source, ensuring improved product purity. The combination of induction heating and a double-layer water-cooling structure enables precise temperature control, improves product quality consistency, avoids interference during material transfer, eliminates pretreatment steps, and reduces material loss and energy costs. It effectively solves the problems of insufficient nitrogen and impurity control, long production cycles, and poor quality stability of traditional monomer equipment, promoting the process-oriented and large-scale development of the silicon carbide raw material industry.

[0066] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A dual-station furnace for high-purity silicon carbide synthesis based on an argon glove box, characterized in that, The system includes a silicon carbide raw material synthesis chamber (1), a heating system (7) is fixedly connected to the outside of the silicon carbide raw material synthesis chamber (1), an upper furnace chamber cover (6) is installed on the top of the silicon carbide raw material synthesis chamber (1), an upper furnace chamber (11) is installed at the bottom of the inner wall of the upper furnace chamber cover (6), a base (8) is installed at the bottom of the silicon carbide raw material synthesis chamber (1), a lower furnace chamber (12) is installed at the bottom of the base (8), a crucible lifting and discharging assembly (10) is provided on the inner wall of the lower furnace chamber (12), a silicon carbide crystal growth chamber one (3) is installed on the right side of the top of the base (8), a silicon carbide crystal growth chamber two (9) is fixedly connected to the outside of the silicon carbide crystal growth chamber one (3), a high vacuum system (5) is installed on the top of the inner wall of the silicon carbide raw material synthesis chamber (1), a transition chamber one (2) is installed on the left side of the lower furnace chamber (12), and a transition chamber two (4) is installed on the right side of the lower furnace chamber (12). The first transition chamber (2) and the second transition chamber (4) are dual-station argon glove boxes. The first transition chamber (2) and the second transition chamber (4) are symmetrically distributed on the left and right sides of the crucible lifting and discharging assembly (10). One end of the high vacuum system (5) passes through the base (8) and is connected to the inner wall of the crucible lifting and discharging assembly (10). The other end of the high vacuum system (5) passes through the upper furnace cover (6) and is connected to the inner wall of the silicon carbide raw material synthesis chamber (1).

2. The high-purity silicon carbide synthesis process using a dual-station furnace according to claim 1, characterized in that: Includes the following steps: S1: The silicon carbide raw material synthesis chamber (1) places the raw material synthesis crucible on the crucible tray of the silicon carbide raw material synthesis chamber (1) through the transition chamber (2). After the crucible rises to the predetermined position, the raw material synthesis process is executed. S2: During the raw material synthesis process in the first transition chamber (2), the newly loaded crucible is placed in the second transition chamber (4) for pre-vacuuming. S3: In the silicon carbide crystal growth chamber 1 (3), after the raw material synthesis is completed, take out the synthesized crucible and put the new material crucible in the transition chamber 2 (4) into the silicon carbide raw material synthesis chamber (1) to continue the raw material synthesis process. S4: In the second transition chamber (4), the silicon carbide crystal growth process is carried out through the first silicon carbide crystal growth chamber (3), and the silicon carbide crystal growth is consistent with the raw material synthesis; S5: Both the silicon carbide raw material synthesis chamber (1) and the silicon carbide crystal growth chamber (3) are equipped with heating systems (7), and the heating systems (7) adopt induction heating.

3. The high-purity silicon carbide synthesis process according to claim 2, characterized in that: The argon purity inside the transition chamber 1 (2) and transition chamber 2 (4) is ≥9N and the water oxygen content is ≤6N. The vacuum port of the high vacuum system (5) is connected to the lower furnace chamber (12) through a slide valve. The vacuum gauge measurement interface is located on the top of the inner wall of the upper furnace chamber (11). The furnace body and pipelines are equipped with shut-off valves. The pumping speed of the high vacuum system (5) is divided into two levels. The pumping methods include pumping through a filter and pumping without a filter.

4. The high-purity silicon carbide synthesis process according to claim 3, characterized in that: The upper furnace chamber cover (6) is a double-layer water-cooled structure, and the upper furnace chamber (11) is a cylindrical vertical double-layer water-cooled structure. The outer wall of the upper furnace chamber cover (6) and the flange are argon arc welded. The interface of the upper furnace chamber cover (6) is sealed with a metal gasket and a fluororubber ring. An infrared thermometer interface is provided on the upper furnace chamber cover (6).

5. The high-purity silicon carbide synthesis process according to claim 4, characterized in that: The base (8) is divided into upper and lower frames. The upper frame is made of high-quality stainless steel and the lower frame is made of high-quality carbon steel. The silicon carbide crystal growth chamber 2 (9) is a vertical double-layer water-cooled structure of quartz tube. The interface of the silicon carbide crystal growth chamber 2 (9) is sealed with fluororubber rings.

6. The high-purity silicon carbide synthesis process according to claim 5, characterized in that: The crucible lifting and discharging assembly (10) is equipped with an external linear unit for discharging material downwards.

7. The high-purity silicon carbide synthesis process according to claim 6, characterized in that: The interior of the silicon carbide crystal growth chamber 2 (9) is a quartz tube. The silicon carbide crystal growth chamber 1 (3) and the silicon carbide raw material synthesis chamber (1) are symmetrically distributed on the top of the base (8).

8. The high-purity silicon carbide synthesis process according to claim 7, characterized in that: The upper furnace chamber (11), the lower furnace chamber (12), and the pipeline and shut-off valve work together to achieve separate vacuuming. The fast pumping mode of the high vacuum system (5) corresponds to two pumping methods: pumping through a filter and pumping without a filter.

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