A powder sintering pretreatment device for a silicon carbide crystal growth furnace

Abstract

This invention relates to the field of crystal growth technology, specifically to a powder sintering pretreatment device for a silicon carbide crystal growth furnace. The device includes a base, a furnace body fixedly connected to the base, a top cover on the furnace body, and a lifting hydraulic cylinder connected to the top cover on the base. A graphite crucible for holding silicon carbide powder is vertically mounted inside the furnace body, with a seed crystal mounting plate on the upper part of the graphite crucible. An in-situ processing mechanism for sintered material blocks is located on the side of the furnace body. The sintering, crushing, and leveling processes of silicon carbide powder are integrated in-situ within the same crystal growth furnace. This dedicated in-situ processing mechanism replaces the traditional step-by-step, multi-equipment, and multi-transfer independent process mode, significantly simplifying the production process, shortening the single-batch production cycle, and avoiding contamination from impurities introduced during material transfer and exposure. This improves powder purity and overall production efficiency while reducing equipment investment and energy consumption.

Description

Technical Field

[0001] This invention relates to the field of crystal growth technology, and more specifically to a powder sintering pretreatment device for a silicon carbide crystal growth furnace. Background Technology

[0002] Silicon carbide (SiC) single crystals are the core substrate of third-generation semiconductor materials. Physical vapor transport (PVT) is currently the mainstream process for preparing high-quality SiC single crystals. In the PVT growth process, the pretreatment quality of the raw material powder directly determines the stability and yield of crystal growth.

[0003] In existing technologies, the sintering pretreatment of SiC powder and single crystal growth are two independent processes, which need to be completed separately in a dedicated sintering furnace and a crystal growth furnace. First, the SiC raw material powder is loaded into a graphite crucible and placed in a separate high-temperature sintering furnace for high-temperature densification under an inert atmosphere. After sintering, the graphite crucible is manually removed from the furnace and cooled. It is then transferred to another working area, where the sintered material is manually crushed to obtain powder with the required particle size. The crushed powder is then reloaded into another set of graphite crucibles and transferred to the crystal growth furnace for single crystal growth (existing growth furnaces such as...). Figure 12 (as shown)

[0004] The aforementioned step-by-step process has significant technical drawbacks: First, the process flow is lengthy and fragmented, with multiple steps such as sintering, crushing, screening, transfer, and secondary loading occurring in sequence, resulting in a significantly extended production cycle and low production efficiency per batch. Second, repeated disassembly and assembly of graphite crucibles, material transfer, and exposure operations easily introduce environmental impurities, dust, and particulate pollution, damaging the purity of raw materials and increasing the crystal defect rate. Third, the dual equipment configuration of independent sintering furnaces and growth furnaces not only increases equipment investment and energy consumption costs, but also the differences in temperature field and atmosphere between the furnaces can easily cause fluctuations in raw material performance, affecting the consistency and controllability of the crystal growth process. Therefore, a powder sintering pretreatment device for silicon carbide crystal growth furnaces is proposed to simplify the production process, improve production efficiency, reduce impurity pollution, and lower equipment and energy consumption costs, thereby improving the stability and yield of silicon carbide crystal growth. Summary of the Invention

[0005] To address the problems in the prior art, this invention provides a powder sintering pretreatment device for silicon carbide crystal growth furnace, which simplifies the production process, improves production efficiency, reduces impurity contamination, and lowers equipment and energy costs, thereby improving the stability and yield of silicon carbide crystal growth.

[0006] The technical solution adopted by the present invention to solve its technical problem is a powder sintering pretreatment device for silicon carbide crystal growth furnace, including a base, a furnace body fixedly connected above the base, a top cover provided on the top of the furnace body, a lifting hydraulic cylinder connected to the top cover on the base, a graphite crucible for carrying silicon carbide powder vertically assembled inside the furnace body, and a seed crystal mounting cover plate provided on the upper part of the graphite crucible.

[0007] The side of the furnace body is equipped with an in-situ treatment mechanism for sintered material blocks. The in-situ treatment mechanism can be moved above the graphite crucible and can move downwards towards the graphite crucible and seal against the upper part of the graphite crucible. The in-situ treatment mechanism can adjust the vibration amplitude by adjusting its downward movement to vibrate and crush the sintered material blocks in the graphite crucible. After the sintered material blocks are crushed, the in-situ treatment mechanism moves upwards and switches its rotation speed, driving its actuators to rotate and level the powder in the graphite crucible to adapt to the subsequent growth of silicon carbide crystals.

[0008] Specifically, the in-situ processing mechanism includes a horizontally arranged support base, a rotating base rotatably connected to the lower part of the support base, and a vibrating actuator head; the rotating base has an installation cavity, and the lower surface of the rotating base has a groove communicating with the installation cavity. The vibrating actuator head is located in the groove and is slidably connected to the groove. A horizontally arranged support plate is fixedly connected to the upper surface of the vibrating actuator head. Several sets of compression springs are fixedly connected between the lower surface of the support plate and the inner wall of the installation cavity. The upper two sides of the vibrating actuator head are provided with a first wedge-shaped surface, and the lower part of the vibrating actuator head is provided with an arc-shaped chamfer.

[0009] The mounting cavity is equipped with an extrusion transmission structure that intermittently extrudes with the first wedge-shaped surface. The bearing seat is equipped with a drive structure that is connected to the extrusion transmission structure to drive the extrusion transmission structure to rotate. The drive structure is connected to the rotating seat through a speed change structure to drive the rotating seat to rotate. The bearing seat is equipped with a hydraulic adjustment system that controls the extrusion amplitude of the extrusion transmission structure according to the downward movement of the vibrating actuator head in the graphite crucible.

[0010] Specifically, the extrusion transmission structure includes an extrusion plate horizontally arranged in the mounting cavity. The lower surface of the extrusion plate is provided with several sets of circumferentially distributed extrusion blocks. The lower sides of the extrusion blocks are provided with second wedge-shaped surfaces. After the extrusion plate moves down, the second wedge-shaped surfaces make extrusion contact with the first wedge-shaped surface on the upper part of the vibrating actuator head.

[0011] Specifically, the drive structure includes a drive motor fixedly connected to the upper part of the support base. The support base has a chamber, and a vertically arranged spline shaft is rotatably connected inside the chamber. The upper end of the spline shaft is coaxially connected to the output end of the drive motor. A spline sleeve is slidably connected to the outside of the spline shaft. The lower end of the spline sleeve passes through the rotating seat and is fixedly connected to the upper surface of the extrusion plate.

[0012] Specifically, the hydraulic adjustment system includes an adjustment ring rotatably connected to the outer side of the top of the spline sleeve, and a first hydraulic telescopic rod connected between the adjustment ring and the top of the inner wall of the cavity;

[0013] And an annular limiting groove is provided on the lower surface of the bearing seat. A sealing ring is slidably connected in the limiting groove. Several sets of circumferentially distributed second hydraulic telescopic rods are fixedly connected between the sealing ring and the inner top of the limiting groove. The second hydraulic telescopic rods are connected to the interior of the first hydraulic telescopic rod through pipelines. A sealing seat is provided on the lower surface of the sealing ring.

[0014] Specifically, the upper surface of the rotating seat is provided with an adjustment groove, and the inner wall of the adjustment groove is provided with several sets of circumferentially distributed tooth structures. The spline sleeve is located outside the adjustment groove and is fixedly connected to the first drive gear and the second drive gear distributed vertically. The adjustment groove is provided with a horizontally arranged transmission gear and a speed-changing gear. The transmission gear is located below the speed-changing gear. Both the transmission gear and the speed-changing gear are rotatably connected to the lower surface of the bearing seat through a rotating shaft. Both the transmission gear and the speed-changing gear are engaged with the tooth structure for transmission. When the spline sleeve moves upward, the first drive gear engages with the speed-changing gear. When the spline sleeve moves downward, the second drive gear engages with the transmission gear.

[0015] Specifically, a support base is provided on one side of the furnace body and is fixedly connected to the upper surface of the base. An electric turntable is rotatably connected to the upper surface of the support base. A vertically set electric hydraulic cylinder is fixedly connected to the upper surface of the electric turntable. The top of the electric hydraulic cylinder is fixedly connected to the bearing seat through a connecting rod.

[0016] Specifically, the vibratory actuator head is made of high-purity isostatic graphite.

[0017] Specifically, the seed crystal mounting cover has a lifting handle at the top and a seed crystal installed at the bottom.

[0018] The beneficial effects of this invention are:

[0019] (1) The silicon carbide crystal growth furnace powder sintering pretreatment device of the present invention integrates the sintering, crushing and leveling processes of silicon carbide powder in situ within the same crystal growth furnace. The dedicated in-situ treatment mechanism replaces the traditional independent process mode of step-by-step, multi-equipment and multiple handling, which significantly simplifies the production process, shortens the production cycle of a single batch, avoids the contamination of impurities introduced during the transfer and exposure of materials, improves the purity of powder and overall production efficiency, and reduces equipment investment and production energy consumption.

[0020] (2) The silicon carbide crystal growth furnace powder sintering pretreatment device of the present invention can achieve gradient adaptation adjustment of the in-situ treatment mechanism according to the adjustment of the vibration amplitude of its own downward movement, so as to realize the gradient vibration crushing of the sintering block in the graphite crucible from small amplitude to large amplitude from top to bottom. Combined with the circumferential rotation action, the block is uniformly crushed throughout the whole area. This not only avoids the problem of incomplete crushing of the corners of the traditional fixed crushing, but also solves the problem of local over-crushing and uncrushed material accumulation in the traditional stirring crushing, ensuring that the particle size of the powder after crushing is uniform and consistent, which is suitable for the raw material requirements of subsequent crystal growth.

[0021] (3) The powder sintering pretreatment device for silicon carbide crystal growth furnace described in this invention realizes the automatic meshing and switching of two sets of gears with different transmission ratios, namely the first drive gear 31, the second drive gear 32 and the transmission gear 33 and the speed change gear 34, through the lifting action of the spline sleeve. During the crushing stage, the rotating seat is driven to rotate at low speed, and during the leveling stage, it is automatically switched to high speed rotation. At the same time as the speed is switched upward, the extrusion plate is driven to disengage from the vibration execution head, realizing the seamless connection between the automatic stop of vibration crushing and rotation leveling. No manual or additional electrical control intervention is required, which greatly improves the automation level and operation efficiency of powder pretreatment. Moreover, the rapid rotation leveling makes the material surface flatter, ensuring the vapor phase molecular directional deposition effect of subsequent physical vapor transport method crystal growth. Attached Figure Description

[0022] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0023] Figure 1 This is an isometric view of the present invention;

[0024] Figure 2 This is an isometric view of the graphite crucible of the present invention;

[0025] Figure 3 This is an isometric view of the present invention from another perspective;

[0026] Figure 4 This is an isometric view of the in-situ processing mechanism of the present invention;

[0027] Figure 5 This is a cross-sectional view of the bearing seat and rotating seat of the present invention;

[0028] Figure 6 This is a cross-sectional view of the rotating seat portion of the present invention;

[0029] Figure 7 This is a schematic diagram of the extrusion plate structure of the present invention;

[0030] Figure 8 This is a cross-sectional structural diagram of the bearing seat portion of the present invention;

[0031] Figure 9 This is a schematic diagram of the support plate connection structure of the present invention;

[0032] Figure 10 This is an isometric view of the graphite crucible of the present invention;

[0033] Figure 11 This is an isometric view of the seed crystal mounting cover plate of the present invention;

[0034] Figure 12 This is a schematic diagram of the prior art structure of the present invention;

[0035] In the diagram: 1. Base; 2. Furnace body; 3. Top cover; 4. Lifting hydraulic cylinder; 5. Graphite crucible; 6. Seed crystal mounting cover plate; 7. Bearing seat; 8. Rotating seat; 9. Vibration actuator head; 10. Mounting cavity; 11. Slide groove; 12. Support plate; 13. Compression spring; 14. First wedge-shaped surface; 15. Arc-shaped chamfer; 16. Compression plate; 17. Compression block; 18. Second wedge-shaped surface; 19. Drive motor; 20. Chamber; 21. Splined shaft; 22. 23. Spline sleeve; 24. Adjusting ring; 25. First hydraulic telescopic rod; 26. Limiting groove; 27. Sealing ring; 28. Second hydraulic telescopic rod; 29. ​​Sealing seat; 30. Adjusting groove; 31. Gear structure; 32. First drive gear; 33. Second drive gear; 34. Transmission gear; 35. Speed ​​change gear; 36. Rotating shaft; 37. Support seat; 38. Electric turntable; 39. Electric hydraulic cylinder; 40. Connecting rod; 41. Lifting handle; 42. Seed crystal. Detailed Implementation

[0036] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0037] To simplify the production process, improve production efficiency, reduce impurity contamination, and lower equipment and energy costs, thereby improving the stability and yield of silicon carbide crystal growth, as one embodiment of the present invention, such as... Figure 1 , Figure 2 , Figure 10 , Figure 11 As shown, the present invention provides a powder sintering pretreatment device for a silicon carbide crystal growth furnace, including a base 1, a furnace body 2 fixedly connected above the base 1, a top cover 3 on the top of the furnace body 2, a lifting hydraulic cylinder 4 connected to the top cover 3 on the base 1, a graphite crucible 5 for carrying silicon carbide powder vertically installed inside the furnace body 2, and a seed crystal mounting cover plate 6 on the upper part of the graphite crucible 5.

[0038] The side of the furnace body 2 is equipped with an in-situ treatment mechanism for sintered material blocks. The in-situ treatment mechanism can be moved to the top of the graphite crucible 5. The in-situ treatment mechanism can move downward towards the graphite crucible 5 and seal and fit with the upper part of the graphite crucible 5. The in-situ treatment mechanism can adjust the vibration amplitude by adjusting its downward movement to vibrate and crush the sintered material blocks in the graphite crucible 5. After the sintered material blocks are crushed, the in-situ treatment mechanism moves upward and switches its rotation speed, driving its actuator to rotate and level the powder in the graphite crucible 5 to adapt to the subsequent growth of silicon carbide crystals.

[0039] In use, an appropriate amount of silicon carbide powder is loaded into the graphite crucible 5 inside the furnace body 2. The top cover 3 is driven down by the lifting hydraulic cylinder 4 to achieve a tight seal of the furnace body 2. Then, the furnace body 2 is heated to 2000℃~2200℃ to perform high-temperature sintering and densification treatment on the silicon carbide powder. After sintering, the furnace body 2 is cooled to a suitable operating temperature, and then the top cover 3 is opened by the lifting hydraulic cylinder 4. The powder sintering is completed by relying on the crystal growth furnace. There is no need to transfer the graphite crucible 5 to a dedicated sintering furnace. There is no need for the dual equipment configuration of sintering furnace and growth furnace, which reduces equipment investment and production energy consumption. The entire process is carried out in a closed furnace to avoid contact between the powder and the external environment, reduce the introduction of impurities from the source, and ensure the purity of the raw materials.

[0040] After the top cover 3 is opened, the in-situ processing mechanism for the sintered material block is moved to the top of the graphite crucible 5. Then, the mechanism is driven to move downwards towards the graphite crucible 5 until it is sealed and fitted to the upper part of the graphite crucible 5. The in-situ processing mechanism adaptively adjusts the vibration amplitude by adjusting its downward movement to achieve gradient matching of vibration amplitude. When it initially moves downwards to the upper area of ​​the graphite crucible 5, it uses small-amplitude vibration. As the mechanism moves downwards, the vibration amplitude increases synchronously and step by step, implementing gradient vibration crushing of the sintered material block in the graphite crucible 5 from top to bottom. During the crushing process, the mechanism synchronously drives the actuator to make small circumferential rotations, achieving uniform crushing of the circular material layer in the graphite crucible 5 until the sintered material block is crushed into powder that meets the requirements of crystal growth particle size. This solves the problems of uneven crushing and difficulty in particle size control in traditional manual crushing. Moreover, the entire crushing process is completed in-situ in the original growth furnace. There is no need to remove the graphite crucible 5 from the furnace body 2 for cooling and transportation. There is no need for the traditional furnace dismantling, transportation, and secondary loading processes, which greatly shortens the production cycle of a single batch and improves production efficiency.

[0041] After the sintered material is completely crushed, the in-situ processing mechanism is driven to move upward. During the upward movement, the mechanism switches its own rotation speed and performs a rotational leveling operation on the crushed powder in the graphite crucible 5 through the actuator until the powder in the graphite crucible 5 forms a flat and uniform material surface. After the leveling is completed, the in-situ processing mechanism is driven to move away from the graphite crucible 5. No manual intervention is required for the leveling operation, avoiding the problems of impurity contamination and poor material surface flatness caused by manual operation, ensuring the uniformity of the material surface, and providing a guarantee for the uniformity of gas phase transport in subsequent crystal growth.

[0042] After the in-situ processing mechanism is removed, the seed crystal mounting cover plate 6 is assembled onto the upper part of the graphite crucible 5. The top cover 3 is then driven down by the lifting hydraulic cylinder 4 to seal the furnace body 2. Subsequently, the furnace temperature is raised to 2300℃~2500℃, and silicon carbide crystal growth is carried out using the physical vapor transport method until single crystal preparation is completed. The entire process, from powder sintering, in-situ crushing, in-situ leveling to crystal growth, is completed in the same silicon carbide crystal growth furnace. The graphite crucible 5 does not need to be removed from the furnace body 2 throughout the process. This effectively solves the problems of reduced raw material purity and high crystal defect rate caused by multiple disassembly and assembly of the graphite crucible 5 and material transfer in the traditional step-by-step process. It improves the stability and yield of silicon carbide crystal growth, as well as the continuity of production and overall production efficiency.

[0043] It should be noted that the bearing seat 7 is designed with an adaptive thickness according to the height requirements of the graphite crucible 5. During the process of the electric hydraulic cylinder 38 driving the bearing seat 7 to move down through the connecting rod 39, the connecting rod 39 and the upper surface of the furnace body 2 always maintain a preset safe distance to avoid the risk of squeezing interference and ensure that the bearing seat 7 and the upper part of the graphite crucible 5 are sealed and fitted.

[0044] To improve the overall uniformity of the crushed powder, for example, such as Figure 3 , Figure 4 , Figure 5 , Figure 9 As shown, the present invention also includes an in-situ processing mechanism comprising a horizontally arranged support seat 7, a rotating seat 8 rotatably connected to the lower part of the support seat 7, and a vibration actuator 9; the rotating seat 8 is provided with an installation cavity 10, the lower surface of the rotating seat 8 is provided with a groove 11 communicating with the installation cavity 10, the vibration actuator 9 is located in the groove 11 and slidably connected to the groove 11, the upper surface of the vibration actuator 9 is fixedly connected with a horizontally arranged support plate 12, the lower surface of the support plate 12 is fixedly connected to the inner wall of the installation cavity 10 with a plurality of compression springs 13, the upper two sides of the vibration actuator 9 are provided with a first wedge-shaped surface 14, and the lower part of the vibration actuator 9 is provided with an arc-shaped chamfer 15;

[0045] The mounting cavity 10 is equipped with an extrusion transmission structure that intermittently extrudes with the first wedge-shaped surface 14. The bearing seat 7 is equipped with a drive structure that is connected to the extrusion transmission structure to drive the extrusion transmission structure to rotate. The drive structure is connected to the rotating seat 8 through a speed change structure to drive the rotating seat 8 to rotate. The bearing seat 7 is equipped with a hydraulic adjustment system that controls the extrusion amplitude of the extrusion transmission structure according to the downward movement amplitude of the vibration actuator 9 in the graphite crucible 5.

[0046] During use, after the powder is sintered and cooled, the bearing seat 7 moves down, driving the rotating seat 8 and the vibrating actuator head 9 to move down synchronously. The hydraulic adjustment system drives the extrusion transmission structure to form an intermittent extrusion fit with the first wedge surface 14 of the vibrating actuator head 9. With the elastic reset of the extrusion spring 13, the high-frequency reciprocating vibration of the vibrating actuator head 9 is realized. The hydraulic adjustment system can adjust the extrusion force and extrusion stroke of the extrusion transmission structure on the first wedge surface 14 in real time according to the downward movement distance of the vibrating actuator head 9 in the graphite crucible 5. As the bearing seat 7 continues to move down, the extrusion force gradually increases, driving the vibration amplitude of the vibrating actuator head 9 to increase synchronously. This ensures that the device can perform gradient crushing of the sintered material blocks in the graphite crucible 5 from top to bottom. Small amplitude vibration is used for the loose material layer in the upper part of the graphite crucible 5 to avoid over-crushing, and large amplitude vibration is used for the dense material layer in the lower part to achieve full crushing. This solves the problem of the upper material layer being over-crushed and the lower material layer not being fully crushed caused by the single vibration amplitude of traditional crushing equipment.

[0047] During the downward movement of the bearing seat 7, the drive structure drives the rotating seat 8 to rotate through the speed-changing structure. The rotation of the rotating seat 8 drives the vibrating actuator head 9 to perform a synchronous circular motion. At the same time, the extrusion transmission structure rotates with the rotating seat 8, and intermittently extrudes the first wedge surface 14 during the rotation. This allows the vibrating actuator head 9 to achieve circumferential crushing while reciprocating. This structure effectively avoids the problem of incomplete crushing of the material blocks at the edges and corners of the graphite crucible 5, which exists in traditional fixed crushing structures. It also has significant advantages over traditional stirring crushing. Traditional stirring crushing relies on the single-point shearing and forced pushing method of the rotating stirring rod, which easily causes excessive crushing of the material layer in the center of the graphite crucible 5, and the material layers at the edges and bottom are uncrushed due to the limited reach of the stirring rod. However, this device ensures that the material blocks are vibrated evenly and crushed layer by layer through the circumferential reciprocating vibration of the vibrating actuator head 9, which greatly improves the overall uniformity of the crushed powder.

[0048] To improve the vibration crushing effect, for example, such as Figure 5 , Figure 6 , Figure 7 As shown, the present invention also includes an extrusion transmission structure comprising an extrusion plate 16 horizontally disposed in the mounting cavity 10, a plurality of circumferentially distributed extrusion blocks 17 on the lower surface of the extrusion plate 16, and a second wedge-shaped surface 18 on both sides of the lower part of the extrusion block 17. After the extrusion plate 16 moves down, the second wedge-shaped surface 18 makes extrusion contact with the first wedge-shaped surface 14 on the upper part of the vibration actuator head 9.

[0049] During use, as the extrusion plate 16 rotates, the extrusion block 17 rotates synchronously and intermittently extrudes through the second wedge surface 18 and the first wedge surface 14 of the vibration actuator head 9, thereby driving the vibration actuator head 9 to move downward and compress the extrusion spring 13; and as the downward movement of the bearing seat 7 increases, the extrusion stroke of the extrusion transmission structure increases synchronously, and the extrusion force is adapted to increase, thereby realizing the synchronous adjustment of the vibration amplitude of the vibration actuator head 9, ensuring that the force of vibration crushing matches the downward movement depth, and improving the vibration crushing effect.

[0050] To facilitate the rotation of the extrusion plate 16, for example, such as Figure 5 , Figure 6 , Figure 8 As shown, the present invention also includes a drive structure comprising a drive motor 19 fixedly connected to the upper part of the support seat 7, a chamber 20 provided inside the support seat 7, a vertically arranged spline shaft 21 rotatably connected inside the chamber 20, the upper end of the spline shaft 21 being coaxially connected to the output end of the drive motor 19, a spline sleeve 22 being slidably connected to the outer side of the spline shaft 21, and the lower end of the spline sleeve 22 passing through the rotating seat 8 and fixedly connected to the upper surface of the extrusion plate 16.

[0051] When in use, after the in-situ processing mechanism is sealed and fitted to the upper part of the graphite crucible 5, the drive motor 19 can be turned on to directly drive the spline shaft 21 to rotate. The spline shaft 21 synchronously drives the spline sleeve 22 to rotate, which in turn drives the extrusion plate 16 to rotate synchronously, so that the extrusion block 17 on the extrusion plate 16 forms intermittent extrusion contact with the first wedge surface 14 of the vibration actuator 9, thereby driving the vibration actuator 9 to complete reciprocating vibration crushing.

[0052] For example, such as Figure 5 , Figure 8 As shown, the present invention also includes a hydraulic adjustment system comprising an adjustment ring 23 rotatably connected to the outer side of the top of the spline sleeve 22, and a first hydraulic telescopic rod 24 connected between the adjustment ring 23 and the top of the inner wall of the chamber 20;

[0053] And an annular limiting groove 25 is provided on the lower surface of the bearing seat 7. A sealing ring 26 is slidably connected in the limiting groove 25. Several sets of circumferentially distributed second hydraulic telescopic rods 27 are fixedly connected between the sealing ring 26 and the inner top of the limiting groove 25. The second hydraulic telescopic rods 27 are connected to the inside of the first hydraulic telescopic rod 24 through pipelines. A sealing seat 28 is provided on the lower surface of the sealing ring 26.

[0054] During use, when the support seat 7 moves downward toward the upper part of the graphite crucible 5, the sealing ring 26 first makes contact with the upper part of the graphite crucible 5, simultaneously compressing the second hydraulic telescopic rod 27. The second hydraulic telescopic rod 27 is connected to the first hydraulic telescopic rod 24 through a pipeline. The pressure transmission of hydraulic oil drives the adjusting ring 23 to move downward, which in turn drives the spline sleeve 22 and the extrusion plate 16 to move downward synchronously. As the downward movement of the support seat 7 gradually increases, the degree of compression of the sealing ring 26 increases synchronously, and the compression of the second hydraulic telescopic rod 27 increases accordingly. Through hydraulic linkage, the first hydraulic telescopic rod is driven. 24. The downward movement of the adjusting ring 23 increases synchronously, thereby pushing the extrusion plate 16 to move continuously downward, increasing the extrusion stroke of the extrusion block 17 and the vibrating actuator 9, and ultimately linearly increasing the vibration amplitude of the vibrating actuator 9. This ensures that the crushing force can be dynamically adapted to the depth of the material layer inside the graphite crucible 5. The upper loose material layer vibrates slightly to avoid over-crushing, while the lower dense material layer vibrates significantly to achieve full crushing. This solves the problem of uneven crushing caused by the fixed vibration amplitude of traditional equipment and achieves crushing of the material layer. At the same time, the sealing seat 28 effectively prevents powder from escaping during the crushing process.

[0055] To facilitate the rotation of the rotating base 8, for example, such as Figure 6 , Figure 7 As shown, the present invention also includes an adjustment groove 29 on the upper surface of the rotating seat 8, and a plurality of circumferentially distributed tooth structures 30 on the inner wall of the adjustment groove 29. A first driving gear 31 and a second driving gear 32, which are distributed vertically, are fixedly connected to the outside of the adjustment groove 29. A transmission gear 33 and a speed-changing gear 34 are arranged horizontally inside the adjustment groove 29. The transmission gear 33 is located below the speed-changing gear 34. The transmission gear 33 and the speed-changing gear 34 are rotatably connected to the lower surface of the bearing seat 7 through a rotating shaft 35. The transmission gear 33 and the speed-changing gear 34 are engaged with the tooth structures 30 for transmission. When the spline sleeve 22 moves upward, the first driving gear 31 engages with the speed-changing gear 34. When the spline sleeve 22 moves downward, the second driving gear 32 engages with the transmission gear 33.

[0056] During use, after the graphite crucible 5 completes the sintering of the powder, the support seat 7 is moved to directly above the graphite crucible 5 and driven to move downwards simultaneously. The sealing ring 26 first presses against the upper part of the graphite crucible 5 and compresses the second hydraulic telescopic rod 27. Through hydraulic linkage, the first hydraulic telescopic rod 24 drives the spline sleeve 22 to move downwards, causing the first drive gear 31 to disengage from the speed change gear 34, and the second drive gear 32 to mesh with the transmission gear 33. By adjusting the gear transmission ratio, the rotation speed of the rotating seat 8 is reduced, driving the vibrating actuator 9 to rotate at a low speed. This, combined with the extrusion action, achieves slow, full-area circumferential crushing of the sintered material block inside the graphite crucible 5, avoiding powder splashing and excessive crushing of local material layers caused by high-speed rotation.

[0057] After crushing, the drive bearing seat 7 gradually moves upward, the extrusion amount of the second hydraulic telescopic rod 27 decreases, and the spline sleeve 22 moves upward through hydraulic linkage, causing the second drive gear 32 to disengage from the transmission gear 33 and the first drive gear 31 to mesh with the speed change gear 34. The rotation speed of the rotating seat 8 is increased by switching the gear transmission ratio. At the same time, the upward movement of the spline sleeve 22 causes the extrusion plate 16 to move upward, causing the second wedge surface 18 to disengage from the first wedge surface 14. The vibration actuator 9 stops vibrating and can then rotate rapidly in a circular motion. The arc chamfer 15 of the vibration actuator 9 is used to quickly rotate and level the powder. This greatly improves the automation level and operating efficiency of in-situ pretreatment in the furnace and avoids the risk of impurity contamination caused by manual intervention throughout the process.

[0058] For example, such as Figure 4 As shown, the present invention also includes a support base 36 fixedly connected to the upper surface of the base 1 on one side of the furnace body 2. An electric turntable 37 is rotatably connected to the upper surface of the support base 36. A vertically arranged electric hydraulic cylinder 38 is fixedly connected to the upper surface of the electric turntable 37. The top end of the electric hydraulic cylinder 38 is fixedly connected to the bearing seat 7 through a connecting rod 39.

[0059] During use, after the top cover 3 is opened after the powder sintering is completed, the electric turntable 37 can drive the electric hydraulic cylinder 38 to rotate, moving the support seat 7 to directly above the graphite crucible 5. There is no need for manual handling or adjustment of the position of the in-situ processing mechanism, which improves the automation level of the operation. The electric hydraulic cylinder 38 drives the support seat 7 to rise and fall through the connecting rod 39. It can adaptively adjust the downward movement distance of the support seat 7 according to the height of the material layer in the graphite crucible 5, adapting to the space requirements of in-situ operation in the furnace, reducing the intensity of manual operation, and improving the overall efficiency and operational safety of pretreatment operation.

[0060] For example, the present invention also includes a vibration actuator 9 made of high-purity isostatic graphite.

[0061] When in use, the high-purity isostatic graphite material has a smooth surface and low affinity for materials, which can effectively prevent silicon carbide powder from adhering to the surface of the vibrating actuator head 9 during the crushing process. This prevents raw material loss caused by powder adhesion, ensures sufficient material in the furnace for subsequent crystal growth, and avoids uneven material layer caused by the falling off of adhered powder. In addition, high-purity isostatic graphite is a compatible material for silicon carbide crystal growth and will not introduce impurities. From the material level, it ensures the high purity of silicon carbide powder and avoids increasing the crystal defect rate due to component material issues, thus providing material guarantee for high-quality crystal growth.

[0062] For example, such as Figure 11 As shown, the present invention also includes a seed crystal mounting cover plate 6 with a lifting handle 40 on the upper part and a seed crystal 41 mounted on the lower part.

[0063] During use, the lifting handle 40 on the upper part of the seed crystal mounting cover 6 provides a convenient force application point for manual and mechanical disassembly and assembly, which can quickly assemble the seed crystal mounting cover 6 onto the upper part of the graphite crucible 5 or remove it from the graphite crucible 5; the seed crystal 41 is installed on the upper part of the graphite crucible 5, which can directly align with the leveled silicon carbide powder, ensuring the directional deposition of gas phase molecules during the physical vapor transport method crystal growth process, improving the verticality and integrity of crystal growth, and effectively improving the growth quality and yield of silicon carbide crystals.

[0064] In use, an appropriate amount of silicon carbide powder is loaded into the graphite crucible 5 inside the furnace body 2. The top cover 3 is driven to move down by the lifting hydraulic cylinder 4 on the base 1, thereby sealing the furnace body 2. This step relies on the crystal growth furnace to complete the subsequent sintering process, eliminating the need to transfer the graphite crucible 5 to a dedicated sintering furnace. This avoids the dual equipment configuration of the sintering furnace and the growth furnace, reducing equipment investment and production energy consumption. At the same time, the sealed furnace body 2 can prevent the powder from contacting the external environment, reducing the introduction of impurities from the source and ensuring the purity of the raw materials.

[0065] The furnace body 2 is heated to 2000℃~2200℃ to perform high-temperature sintering and densification treatment on silicon carbide powder. After sintering, the furnace body 2 is cooled to a suitable operating temperature, and the top cover 3 is opened by lifting hydraulic cylinder 4. The entire furnace is sealed for sintering, which further ensures that the silicon carbide powder is not contaminated by the outside world and maintains the high purity of the raw materials.

[0066] The electric turntable 37 on the support base 36 on one side of the furnace body 2 rotates, driving the electric hydraulic cylinder 38 to rotate. At the same time, the electric hydraulic cylinder 38 drives the bearing seat 7 to rise and fall through the connecting rod 39, moving the sintered material block in-situ processing mechanism to directly above the graphite crucible 5. This operation does not require manual handling or adjustment of the position of the in-situ processing mechanism, improving the automation level of the operation. The in-situ processing mechanism is driven to move downward towards the graphite crucible 5. The sealing ring 26 first makes contact with the upper part of the graphite crucible 5 by compression. The hydraulic adjustment system drives the compression transmission structure to form an intermittent compression cooperation with the first wedge surface 14 of the vibration actuator 9 through hydraulic linkage. As the downward movement of the mechanism increases, the vibration amplitude increases step by step, realizing the gradient vibration crushing of the sintered material block from top to bottom.

[0067] Simultaneously, the drive structure, through a speed-changing mechanism, drives the rotating seat 8 and the vibrating actuator 9 to rotate at low speed in a circular pattern, completing the uniform crushing of the circular material layer inside the graphite crucible 5 until the sintered material is crushed into powder that meets the requirements for crystal growth particle size. Through gradient vibration, small-amplitude vibration is used for the upper loose material layer to avoid over-crushing, while large-amplitude vibration is used for the lower dense material layer to achieve thorough crushing, solving the problem of uneven crushing caused by the single vibration amplitude of traditional crushing equipment. The circular rotation crushing method avoids the problems of incomplete edge crushing in traditional fixed crushing and local over-crushing and uncrushed material accumulation in stirring crushing, ensuring that the particle size of the crushed powder is uniform. In-situ crushing eliminates the need to remove the graphite crucible 5 from the furnace body 2 for cooling and transportation, saving the traditional furnace dismantling, transportation, and secondary loading processes, significantly shortening the single-batch production cycle and improving production efficiency. The sealing seat 28 can effectively prevent powder from escaping during the crushing process.

[0068] After the sintered material is completely crushed, the in-situ processing mechanism is driven upward, and the hydraulic adjustment system moves the spline sleeve 22 upward, realizing the automatic meshing and switching of the first drive gear 31, the second drive gear 32, and the transmission gear 33 and the speed change gear 34, which are two sets of gears with different transmission ratios. The rotating seat 8 switches from low-speed rotation to high-speed rotation. At the same time, the upward movement of the spline sleeve 22 drives the extrusion plate 16 upward, causing the extrusion plate 16 to disengage from the vibration actuator head 9. The vibration actuator head 9 stops vibrating and uses the arc-shaped chamfer 15 at its lower part to contact the graphite crucible. The crushed powder in crucible 5 is rapidly rotated and leveled until a flat and uniform surface is formed. After leveling, the in-situ processing mechanism is moved away from the graphite crucible 5. This step requires no manual or additional electrical control intervention, achieving a seamless connection between automatic stopping of vibration crushing and rotational leveling, which greatly improves the automation level and work efficiency of powder pretreatment. Rapid rotational leveling makes the surface flatter and more uniform, avoiding the problems of impurity contamination and poor surface flatness caused by manual operation, and ensuring the uniformity of gas phase transport for subsequent crystal growth.

[0069] The seed crystal is installed on the upper part of the cover plate 6 by lifting the handle 40, which is quickly assembled onto the upper part of the graphite crucible 5. Then, the top cover 3 is driven to move down by the lifting hydraulic cylinder 4 to achieve secondary sealing of the furnace body 2. The lifting handle 40 provides a convenient force point for the disassembly and assembly of the cover plate, which can quickly complete the assembly operation. The seed crystal 41 is installed on the upper part of the graphite crucible 5 and can be aligned with the leveled silicon carbide powder to ensure the directional deposition of gas phase molecules during the subsequent physical vapor transport method crystal growth process.

[0070] The furnace temperature is raised to 2300℃~2500℃, and silicon carbide crystal growth is carried out using the physical vapor transport method until single crystal preparation is completed. From powder sintering, in-situ crushing, in-situ leveling to crystal growth, the entire process is completed in the same silicon carbide crystal growth furnace. The graphite crucible 5 does not need to be removed from the furnace body 2 throughout the process, which effectively solves the problems of reduced raw material purity and high crystal defect rate caused by multiple disassembly and assembly of graphite crucible 5 and material transfer in the traditional step-by-step process. It significantly improves the stability and yield of silicon carbide crystal growth, while greatly improving production continuity and overall production efficiency.

[0071] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of protection claimed by the present invention. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A powder sintering pretreatment device for a silicon carbide crystal growth furnace, characterized in that, Includes a base (1), a furnace body (2) fixed above the base (1), a top cover (3) on the top of the furnace body (2), a lifting hydraulic cylinder (4) connected to the top cover (3) on the base (1), a graphite crucible (5) for carrying silicon carbide powder is vertically installed inside the furnace body (2), and a seed crystal mounting cover plate (6) is provided on the upper part of the graphite crucible (5). The side of the furnace body (2) is provided with an in-situ treatment mechanism for sintered material blocks. The in-situ treatment mechanism can be moved to the top of the graphite crucible (5). The in-situ treatment mechanism can move downward towards the graphite crucible (5) and seal and fit with the upper part of the graphite crucible (5). The in-situ treatment mechanism can adjust the vibration amplitude by adjusting its downward movement to vibrate and crush the sintered material blocks in the graphite crucible (5). After the sintered material blocks are crushed, the in-situ treatment mechanism moves upward and switches its rotation speed, driving its execution components to rotate and level the powder in the graphite crucible (5) to adapt to the subsequent growth of silicon carbide crystals.

2. The powder sintering pretreatment device for a silicon carbide crystal growth furnace according to claim 1, characterized in that, The in-situ processing mechanism includes a horizontally arranged support seat (7), a rotating seat (8) rotatably connected to the lower part of the support seat (7), and a vibration actuator (9); the rotating seat (8) is provided with an installation cavity (10), the lower surface of the rotating seat (8) is provided with a groove (11) communicating with the installation cavity (10), the vibration actuator (9) is located in the groove (11) and is slidably connected to the groove (11), the upper surface of the vibration actuator (9) is fixedly connected with a horizontally arranged support plate (12), the lower surface of the support plate (12) is fixedly connected to the inner wall of the installation cavity (10) with several sets of compression springs (13), the upper two sides of the vibration actuator (9) are provided with a first wedge-shaped surface (14), and the lower part of the vibration actuator (9) is provided with an arc-shaped chamfer (15). The mounting cavity (10) is provided with an extrusion transmission structure that intermittently extrudes with the first wedge surface (14). The bearing seat (7) is equipped with a drive structure that is connected to the extrusion transmission structure to drive the extrusion transmission structure to rotate. The drive structure is connected to the rotating seat (8) through a speed change structure to drive the rotating seat (8) to rotate. The bearing seat (7) is provided with a hydraulic adjustment system that controls the extrusion amplitude of the extrusion transmission structure according to the downward movement of the vibration actuator (9) in the graphite crucible (5).

3. The powder sintering pretreatment device for a silicon carbide crystal growth furnace according to claim 2, characterized in that, The extrusion transmission structure includes an extrusion plate (16) horizontally arranged in the mounting cavity (10). The lower surface of the extrusion plate (16) is provided with several sets of circumferentially distributed extrusion blocks (17). The lower sides of the extrusion blocks (17) are provided with second wedge surfaces (18). After the extrusion plate (16) moves down, the second wedge surfaces (18) and the first wedge surfaces (14) on the upper part of the vibration actuator head (9) are in extrusion contact.

4. The powder sintering pretreatment device for a silicon carbide crystal growth furnace according to claim 3, characterized in that, The drive structure includes a drive motor (19) fixedly connected to the upper part of the support (7). The support (7) has a chamber (20). A vertically arranged spline shaft (21) is rotatably connected in the chamber (20). The upper end of the spline shaft (21) is coaxially connected to the output end of the drive motor (19). A spline sleeve (22) is slidably connected to the outside of the spline shaft (21). The lower end of the spline sleeve (22) passes through the rotating seat (8) and is fixedly connected to the upper surface of the extrusion plate (16).

5. The powder sintering pretreatment device for a silicon carbide crystal growth furnace according to claim 4, characterized in that, The hydraulic adjustment system includes an adjustment ring (23) rotatably connected to the outer side of the top of the spline sleeve (22), and a first hydraulic telescopic rod (24) connected between the adjustment ring (23) and the top of the inner wall of the chamber (20). And an annular limiting groove (25) is provided on the lower surface of the bearing seat (7). A sealing ring (26) is slidably connected in the limiting groove (25). Several sets of circumferentially distributed second hydraulic telescopic rods (27) are fixedly connected between the sealing ring (26) and the inner top of the limiting groove (25). The second hydraulic telescopic rods (27) are connected to the inside of the first hydraulic telescopic rod (24) through a pipeline. A sealing seat (28) is provided on the lower surface of the sealing ring (26).

6. The powder sintering pretreatment device for a silicon carbide crystal growth furnace according to claim 5, characterized in that, The upper surface of the rotating seat (8) is provided with an adjustment groove (29). The inner wall of the adjustment groove (29) is provided with several sets of circumferentially distributed tooth structures (30). The spline sleeve (22) is located outside the adjustment groove (29) and is fixedly connected with the first drive gear (31) and the second drive gear (32) distributed vertically. The adjustment groove (29) is provided with a horizontally arranged transmission gear (33) and a speed-changing gear (34). The transmission gear (33) is located below the speed-changing gear (34). The transmission gear (33) and the speed-changing gear (34) are rotatably connected to the lower surface of the bearing seat (7) through the rotating shaft (35). The transmission gear (33) and the speed-changing gear (34) are meshed with the tooth structure (30) for transmission. When the spline sleeve (22) moves up, the first drive gear (31) meshes with the speed-changing gear (34). When the spline sleeve (22) moves down, the second drive gear (32) meshes with the transmission gear (33).

7. The powder sintering pretreatment device for a silicon carbide crystal growth furnace according to claim 6, characterized in that, The furnace body (2) is provided with a support seat (36) fixedly connected to the upper surface of the base (1) on one side. An electric turntable (37) is rotatably connected to the upper surface of the support seat (36). A vertically arranged electric hydraulic cylinder (38) is fixedly connected to the upper surface of the electric turntable (37). The top of the electric hydraulic cylinder (38) is fixedly connected to the bearing seat (7) through a connecting rod (39).

8. The powder sintering pretreatment device for a silicon carbide crystal growth furnace according to claim 7, characterized in that, The vibratory actuator (9) is made of high-purity isostatic graphite.

9. The powder sintering pretreatment device for a silicon carbide crystal growth furnace according to claim 8, characterized in that, The seed crystal mounting cover plate (6) has a lifting handle (40) on the upper part and a seed crystal (41) installed on the lower part.

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