A graphite crucible lifting device for a single crystal furnace

Abstract

The application belongs to the field of single crystal furnaces, and particularly relates to a single crystal furnace graphite crucible lifting device, which comprises a supporting seat, a fixing frame fixedly connected to the top end of the supporting seat, a single crystal furnace main body fixedly connected to the top end of the fixing frame, a seed crystal shaft fixedly connected to the top end of the single crystal furnace main body, a fixing box fixedly connected to the bottom end of the single crystal furnace main body, a pair of lead screws fixedly connected to the inner side wall of the supporting seat, a lifting frame threadedly connected to the middle part of the lead screw, a placing table rotatably connected to the top end of the lifting frame, a motor fixedly connected to the bottom end of the lifting frame, and the placing table connected to the output end of the motor. The heat insulation plate is lifted along with the lifting frame to form a fence around the connection area of the lead screw and the lifting frame, the heat transferred to the top of the lifting frame is blocked, the influence of the high-temperature heat transferred downward along the lifting frame to the threaded connection area of the lead screw is reduced, the change of the thread gap and the risk of the reduction of the transmission precision caused by the thermal expansion of the lead screw are reduced.

Description

Technical Field

[0001] This invention relates to the field of single crystal furnaces, specifically a graphite crucible lifting device for single crystal furnaces. Background Technology

[0002] The single crystal furnace is a core thermal equipment for preparing single crystal silicon crystals based on the Czochralski method. It is used to grow complete single crystal silicon rods. Single crystal silicon has excellent semiconductor electrical properties, and the produced silicon wafers are widely used in photovoltaic solar cells, integrated circuit chips, semiconductor discrete devices, sensors and other fields. It is a basic production equipment for the new energy photovoltaic industry and the microelectronics semiconductor industry.

[0003] The single crystal furnace first evacuates the furnace cavity and then fills it with argon to form an inert protective atmosphere. The graphite heater is energized and heats up the polycrystalline silicon raw material in the graphite crucible to a molten state. After the temperature of the silicon melt stabilizes, the lifting device carries the seed crystal down to contact the liquid surface. Through the processes of crystal pulling, shoulder forming, equal diameter forming, and finishing, in conjunction with the rotation of the seed crystal and the crucible, the height of the crucible is continuously adjusted by the crucible lifting device to compensate for the drop in the molten silicon level, so that the silicon atoms are oriented and crystallized along the seed crystal, and a complete single crystal silicon rod is gradually grown. After the crystal growth is completed, it is cooled down and taken out of the furnace.

[0004] Most existing single crystal furnace lifting devices are exposed to the elements, and the high-temperature crucible radiates a large amount of heat outward, which can easily cause thermal deformation of drive components such as lead screws, resulting in a decrease in transmission accuracy. Therefore, in order to address the above problems, a graphite crucible lifting device for single crystal furnaces is proposed. Summary of the Invention

[0005] In order to overcome the shortcomings of the prior art, at least one technical problem raised in the background art is solved.

[0006] The technical solution adopted by this invention to solve its technical problem is as follows: A graphite crucible lifting device for a single crystal furnace, comprising a support base; a fixed frame fixedly connected to the top of the support base; a single crystal furnace body fixedly connected to the top of the fixed frame; a seed crystal shaft fixedly connected to the top of the single crystal furnace body; a fixed box fixedly connected to the bottom of the single crystal furnace body; a pair of lead screws fixedly connected to the inner wall of the support base; a lifting frame threadedly connected to the middle of the lead screws; a placement platform rotatably connected to the top of the lifting frame; a motor fixedly connected to the bottom of the lifting frame; a placement platform connected to the output end of the motor; a pair of heat insulation plates fixedly connected to the top of the lifting frame; the heat insulation plates are positioned to the side of the lead screws; a pair of heat insulation covers fixedly connected to the inner wall of the support base; a heat insulation bellows cover fixedly connected to the middle of the heat insulation covers; the heat insulation bellows cover is connected to the middle of the lifting frame; and a crucible body is positioned at the top of the placement platform.

[0007] Preferably, the top of the placement platform is provided with multiple sets of support rods; the support rods are L-shaped; and multiple sets of graphite pads are fixed to the top of the support rods.

[0008] Preferably, the top of the placement platform is fixedly connected to multiple sets of sliding grooves; a slider is slidably connected to the middle of the sliding groove; and a fixing bolt is threadedly connected to the top of the slider.

[0009] Preferably, a baffle is slidably connected to the middle of the heat insulation plate; bolts are threadedly connected to the side wall of the heat insulation plate; and the bolts are connected to the side wall of the baffle.

[0010] Preferably, a pair of slide rails are fixedly connected to the side wall of the support base; a connecting groove is provided in the middle of the slide rails; and the lifting frame is slidably connected to the connecting groove.

[0011] Preferably, a pair of scrapers are fixedly connected to the top of the lifting frame; the scrapers are slidably connected to the connecting groove and the lead screw.

[0012] Preferably, a retaining edge is fixed to the top of the placement platform; the retaining edge is located around the crucible body.

[0013] Preferably, a heat insulation pad is fixed to the side wall of the heat insulation plate; a heat insulation pad is fixed to the bottom end of the lifting frame.

[0014] The advantages of this invention are: 1. The present invention provides a graphite crucible lifting device for a single crystal furnace. A heat insulation plate, as the lifting frame rises and falls, forms a barrier around the connection area between the lead screw and the lifting frame, blocking heat transmitted from the top of the lifting frame. This reduces the impact of high-temperature heat being transferred downwards along the lifting frame to the threaded mating area of ​​the lead screw, mitigating the risk of changes in thread clearance and decreased transmission accuracy due to thermal expansion of the lead screw. The heat-insulating bellows cover dynamically covers the lead screw during the lifting frame's movement, isolating the threaded surface of the lead screw from the radiant heat source of the crucible body, reducing the thermal impact of high-temperature radiation on the lead screw surface. The heat insulation cover provides installation support for the heat-insulating bellows cover, enabling the cover to maintain a stable expansion and contraction state during the lifting frame's movement.

[0015] 2. The graphite crucible lifting device for a single crystal furnace described in this invention provides multi-point support for the bottom of the crucible body by the L-shaped support rod, so that the crucible body remains stable during placement and rotation. Graphite pads are spaced between the support rod and the crucible body to reduce heat conduction caused by direct contact between the bottom of the crucible body and the support rod, thereby reducing the thermal impact of high temperature on the support rod. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the main body of the present invention; Figure 2 This is a schematic diagram of the placement platform in this invention; Figure 3 This is a schematic diagram of the structure of the heat-insulating bellows cover in this invention; Figure 4 This is a schematic diagram of the structure of the heat insulation pad in this invention; Figure 5 This is a schematic diagram of the support rod in this invention; Figure 6 This is a schematic diagram of the lead screw in this invention.

[0018] In the diagram: 1. Support base; 11. Fixing frame; 12. Single crystal furnace body; 13. Seed crystal shaft; 14. Fixing box; 15. Lead screw; 16. Lifting frame; 17. Placement platform; 18. Motor; 19. Heat insulation plate; 110. Heat insulation cover; 111. Heat insulation bellows cover; 112. Crucible body; 2. Support rod; 21. Graphite pad; 3. Slide groove; 31. Sliding block; 32. Fixing bolt; 4. Baffle; 41. Bolt; 5. Slide rail; 51. Connecting groove; 6. Scraper; 7. Edge retainer; 8. Heat insulation pad. Detailed Implementation

[0019] 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.

[0020] Specific implementation examples are given below.

[0021] like Figures 1 to 5As shown in the embodiment of the present invention, a graphite crucible lifting device for a single crystal furnace includes a support base 1; a fixing frame 11 is fixedly connected to the top of the support base 1; a single crystal furnace body 12 is fixedly connected to the top of the fixing frame 11; a seed crystal shaft 13 is fixedly connected to the top of the single crystal furnace body 12; a fixing box 14 is fixedly connected to the bottom of the single crystal furnace body 12; a pair of lead screws 15 are fixedly connected to the inner side wall of the support base 1; a lifting frame 16 is threadedly connected to the middle of the lead screws 15; a placement platform 17 is rotatably connected to the top of the lifting frame 16; a motor 18 is fixedly connected to the bottom of the lifting frame 16; the output end of the motor 18 is connected to... A placement platform 17 is provided; a pair of heat insulation plates 19 are fixedly connected to the top of the lifting frame 16; the heat insulation plates 19 are located on the side of the lead screw 15; a pair of heat insulation covers 110 are fixedly connected to the inner wall of the support base 1; a heat insulation bellows cover 111 is fixedly connected to the middle of the heat insulation cover 110; the heat insulation bellows cover 111 is connected to the middle of the lifting frame 16; a crucible body 112 is provided at the top of the placement platform 17; during operation, the crucible body 112 is placed on the top of the placement platform 17, the drive source inside the fixing box 14 is activated to drive the lead screw 15 to rotate, the lead screw 15 threadedly drives the lifting frame 16 to rise and fall, the lifting frame 16... The 6 motor drives the placement stage 17 and the crucible body 112 to be lifted synchronously. The crucible body 112 carries the silicon raw material in the single crystal furnace and works with the seed crystal shaft 13 to complete the single crystal growth process. After the single crystal growth is completed, the drive source inside the fixing box 14 drives the lead screw 15 to rotate in the opposite direction. The lead screw 15 drives the lifting frame 16 to descend along the axial direction of the lead screw 15. The lifting frame 16 drives the placement stage 17 and the crucible body 112 to descend synchronously, sending the crucible body 112 out of the single crystal furnace. During the lifting and lowering process of the crucible body 112, the motor 18 starts and drives the placement stage 17 to rotate. The placement stage 17 drives the crucible body 112 to rotate synchronously. The crucible body 112 is rotated in a step-by-step manner during the lifting and lowering process, which, together with the seed crystal shaft 13, completes the rotation process requirements for single crystal growth. During the lifting and lowering process, the heat insulation bellows cover 111 of the lifting frame 16 extends and retracts synchronously with the movement of the lifting frame 16, dynamically covering the sliding area of ​​the lead screw 15 and isolating the threaded surface of the lead screw 15 from the radiant heat source of the crucible body 112. The heat insulation plate 19 rises and falls synchronously with the lifting frame 16, forming a barrier around the connection area between the lead screw 15 and the lifting frame 16, reducing the transfer of high-temperature heat from the crucible body 112 area to the threaded mating area of ​​the lead screw 15 and the lifting frame 16.Driven by the motor 18, the placement platform 17 rotates the crucible body 112, maintaining its rotation during lifting and lowering. This, in conjunction with the seed crystal shaft 13, fulfills the rotational process requirements for single crystal growth. The heat insulation plate 19, rising and falling with the lifting frame 16, forms a barrier around the connection area between the lead screw 15 and the lifting frame 16, blocking heat transfer from the top of the lifting frame 16 and reducing the impact of high-temperature heat transfer downwards along the lifting frame 16 to the threaded mating area of ​​the lead screw 15. This reduces the risk of changes in thread clearance and decreased transmission accuracy due to thermal expansion of the lead screw 15. The heat-insulating bellows cover 111 dynamically covers the lead screw 15 during the lifting and lowering of the lifting frame 16, isolating the threaded surface of the lead screw 15 from the radiant heat source of the crucible body 112, reducing the thermal impact of high-temperature radiation on the surface of the lead screw 15. The heat insulation cover 110 provides installation support for the heat-insulating bellows cover 111, enabling the heat-insulating bellows cover 111 to maintain a stable expansion and contraction state during the lifting and lowering of the lifting frame 16.

[0022] like Figure 5 As shown, the top of the placement platform 17 is provided with multiple sets of support rods 2; the support rods 2 are L-shaped; multiple sets of graphite pads 21 are fixed to the top of the support rods 2; during operation, the crucible body 112 is placed on the top of the support rods 2, and the graphite pads 21 are located between the contact surfaces of the support rods 2 and the crucible body 112, so that a gap is formed between the bottom of the crucible body 112 and the top of the support rods 2; the L-shape of the support rods 2 provides multi-point support for the bottom of the crucible body 112, so that the crucible body 112 remains stable during placement and rotation. The graphite pads 21 are spaced between the support rods 2 and the crucible body 112, reducing the heat conduction generated by the direct contact between the bottom of the crucible body 112 and the support rods 2, and reducing the thermal impact of high temperature on the support rods 2.

[0023] like Figure 5 As shown, the top of the placement platform 17 is fixedly connected to multiple sets of sliding grooves 3; a slider 31 is slidably connected to the middle of the sliding groove 3; a fixing bolt 32 is threadedly connected to the top of the slider 31; during operation, according to the diameter of the crucible body 112, the slider 31 is pushed to slide in the sliding groove 3, and the slider 31 drives the support rod 2 to move, adjusting the spacing between the multiple sets of support rods 2 so that the support rod 2 matches the support position of the bottom of the crucible body 112; the sliding cooperation between the sliding groove 3 and the slider 31 realizes the flexible adjustment of the support position of the support rod 2, so that the structure of the support rod 2 can adapt to the placement requirements of crucible bodies 112 of different diameters, improving the versatility of the support rod 2.

[0024] like Figure 4As shown, a baffle 4 is slidably connected to the middle of the heat insulation plate 19; a bolt 41 is threadedly connected to the side wall of the heat insulation plate 19; the bolt 41 is connected to the side wall of the baffle 4; during operation, according to the height of the crucible body 112, a pushing and pulling force is applied to the baffle 4 to make it slide within the heat insulation plate 19, adjusting the shielding height of the baffle 4 so that the top of the baffle 4 extends to the shielding position corresponding to the side wall of the crucible body 112. After adjustment, the bolt 41 is tightened to fix the baffle 4 to the heat insulation plate 19; the shielding height is adjusted by the sliding cooperation between the baffle 4 and the heat insulation plate 19, so that the heat insulation plate 19 and the baffle 4 can be adjusted to a suitable shielding range according to the different heights of the crucible body 112, reducing the heat transfer to the screw 15 area due to insufficient shielding height.

[0025] like Figure 6 As shown, a pair of slide rails 5 are fixedly connected to the side wall of the support base 1; a connecting groove 51 is provided in the middle of the slide rail 5; the lifting frame 16 is slidably connected to the connecting groove 51; during operation, when the lifting frame 16 is lifted and lowered under the drive of the lead screw 15, the side wall of the lifting frame 16 and the connecting groove 51 maintain sliding contact, and the connecting groove 51 guides the lifting and lowering movement of the lifting frame 16; the sliding cooperation between the slide rail 5 and the connecting groove 51 provides auxiliary guidance for the lifting and lowering of the lifting frame 16, so that the lifting frame 16 remains vertical during the lifting and lowering process, reducing the wear of the lifting frame 16 due to tilting.

[0026] like Figure 6 As shown, a pair of scrapers 6 are fixedly connected to the top of the lifting frame 16; the scrapers 6 are slidably connected to the connecting groove 51 and the lead screw 15; during operation, when the lifting frame 16 is raised and lowered, the scrapers 6 move synchronously with the lifting frame 16, and the scrapers 6 maintain sliding contact with the inner wall of the connecting groove 51 and the surface of the lead screw 15 respectively, scraping away the dust and impurities attached to the inner wall of the connecting groove 51 and the surface of the lead screw 15; by cleaning the surface of the connecting groove 51 and the lead screw 15 synchronously by the scrapers 6 during the raising and lowering of the lifting frame 16, the accumulation of dust and impurities on the surface of the connecting groove 51 and the lead screw 15 is reduced, which would lead to increased sliding resistance or jamming.

[0027] like Figure 5 As shown, a baffle 7 is fixed to the top of the placement platform 17; the baffle 7 is arranged around the crucible body 112; during operation, the carbonized dust released by the crucible body 112 in the high-temperature environment falls into the baffle 7, and the baffle 7 surrounds and gathers the falling dust; by receiving and surrounding the carbonized dust falling around the crucible body 112, the baffle 7 reduces the amount of dust scattered at the bottom of the single crystal furnace body 12.

[0028] like Figures 4 to 5As shown, a heat insulation pad 8 is fixedly connected to the side wall of the heat insulation plate 19; a heat insulation pad 8 is fixedly connected to the bottom end of the lifting frame 16; during operation, the heat insulation pads 8 are respectively set on the side wall of the heat insulation plate 19 and the bottom end of the lifting frame 16 to further isolate the heat transferred to the heat insulation plate 19 and the lifting frame 16; the heat insulation formed by the heat insulation pads 8 on the side wall of the heat insulation plate 19 and the bottom end of the lifting frame 16 increases the heat barrier to the lead screw 15 and the motor 18, and further reduces the transfer of high temperature heat to the area of ​​the lead screw 15 and the motor 18 through the heat insulation plate 19 and the lifting frame 16.

[0029] Working principle: The crucible body 112 is placed on top of the placement stage 17. The drive source inside the fixing box 14 is activated, driving the lead screw 15 to rotate. The lead screw 15, in conjunction with the threaded engagement, drives the lifting frame 16 to rise and fall. The lifting frame 16 drives the placement stage 17 and the crucible body 112 to rise synchronously. The crucible body 112 carries the silicon raw material in the single crystal furnace and, in conjunction with the seed crystal shaft 13, completes the single crystal growth process. After the single crystal growth is completed, the drive source inside the fixing box 14 drives the lead screw 15 to rotate in the opposite direction. The lead screw 15 drives the lifting frame 16 to descend along the axial direction of the lead screw 15. The lifting frame 16 drives the placement stage 17 and the crucible body 112 to descend synchronously, sending the crucible body 112 out of the single crystal furnace. During the lifting and lowering process of the crucible body 112, the electric current... The machine 18 starts, driving the placement platform 17 to rotate. The placement platform 17 drives the crucible body 112 to rotate synchronously, keeping the crucible body 112 rotating during the lifting and lowering process. This, in conjunction with the seed crystal axis 13, completes the rotational process requirements for single crystal growth. During the lifting and lowering process, the heat insulation bellows cover 111 of the lifting frame 16 extends and retracts synchronously with the movement of the lifting frame 16, dynamically covering the sliding area of ​​the lead screw 15 and isolating the threaded surface of the lead screw 15 from the radiant heat source of the crucible body 112. The heat insulation plate 19 rises and falls synchronously with the lifting frame 16, forming a barrier around the connection area between the lead screw 15 and the lifting frame 16, reducing the transfer of high-temperature heat from the crucible body 112 area to the threaded mating area of ​​the lead screw 15 and the lifting frame 16. The crucible body 112 is then erected. At the top of the support rod 2, a graphite pad 21 is located between the contact surface of the support rod 2 and the crucible body 112, creating a gap between the bottom of the crucible body 112 and the top of the support rod 2. Based on the diameter of the crucible body 112, the slider 31 is pushed to slide within the groove 3. The slider 31 moves the support rod 2, adjusting the spacing between multiple sets of support rods 2 to match the support position of the support rod 2 with the bottom of the crucible body 112. Based on the height of the crucible body 112, a pushing and pulling force is applied to the baffle 4 to make it slide within the heat insulation plate 19. The blocking height of the baffle 4 is adjusted so that the top of the baffle 4 extends to the blocking position corresponding to the side wall of the crucible body 112. After adjustment, the bolt 41 is tightened to fix the baffle 4 to the heat insulation plate 19. When the lifting frame 16 is raised and lowered under the drive of the lead screw 15, the side wall of the lifting frame 16 maintains sliding contact with the connecting groove 51. The connecting groove 51 guides the lifting movement of the lifting frame 16. When the lifting frame 16 is raised and lowered, the scraper 6 moves synchronously with the lifting frame 16. The scraper 6 maintains sliding contact with the inner wall of the connecting groove 51 and the surface of the lead screw 15 respectively, scraping away the dust and impurities attached to the inner wall of the connecting groove 51 and the surface of the lead screw 15. The carbonized dust released by the crucible body 112 in the high temperature environment falls into the inside of the baffle 7. The baffle 7 surrounds and gathers the falling dust. The heat insulation pads 8 are respectively set on the side wall of the heat insulation plate 19 and the bottom of the lifting frame 16 to further isolate the heat transferred to the heat insulation plate 19 and the lifting frame 16.

[0030] 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 the claimed invention.

Claims

1. A lifting device for a graphite crucible in a single crystal furnace, characterized in that: The system includes a support base (1); a fixing frame (11) is fixedly connected to the top of the support base (1); a single crystal furnace body (12) is fixedly connected to the top of the fixing frame (11); a seed crystal shaft (13) is fixedly connected to the top of the single crystal furnace body (12); a fixing box (14) is fixedly connected to the bottom of the single crystal furnace body (12); a pair of lead screws (15) are fixedly connected to the inner side wall of the support base (1); a lifting frame (16) is threadedly connected to the middle of the lead screws (15); a placement platform (17) is rotatably connected to the top of the lifting frame (16); the lifting frame (16)... A motor (18) is fixed to the bottom end; the output end of the motor (18) is connected to a placement platform (17); a pair of heat insulation plates (19) are fixed to the top of the lifting frame (16); the heat insulation plates (19) are located on the side of the lead screw (15); a pair of heat insulation covers (110) are fixed to the inner wall of the support base (1); a heat insulation bellows cover (111) is fixed to the middle of the heat insulation cover (110); the heat insulation bellows cover (111) is connected to the middle of the lifting frame (16); a crucible body (112) is provided at the top of the placement platform (17).

2. The graphite crucible lifting device for a single crystal furnace according to claim 1, characterized in that: A baffle (4) is slidably connected to the middle of the heat insulation plate (19); a bolt (41) is threadedly connected to the side wall of the heat insulation plate (19); the bolt (41) is connected to the side wall of the baffle (4).

3. The graphite crucible lifting device for a single crystal furnace according to claim 2, characterized in that: The top of the placement platform (17) is fixed with a retaining edge (7); the retaining edge (7) is located around the crucible body (112).

4. The graphite crucible lifting device for a single crystal furnace according to claim 3, characterized in that: The side wall of the heat insulation board (19) is fixed with a heat insulation pad (8); the bottom end of the lifting frame (16) is fixed with a heat insulation pad (8).

5. A graphite crucible lifting device for a single crystal furnace according to claim 1, characterized in that: The top of the placement platform (17) is provided with multiple sets of support rods (2); the support rods (2) are L-shaped; and multiple sets of graphite pads (21) are fixed to the top of the support rods (2).

6. A graphite crucible lifting device for a single crystal furnace according to claim 5, characterized in that: The top of the placement platform (17) is fixed with multiple sets of sliding grooves (3); a slider (31) is slidably connected in the middle of the sliding groove (3); and a fixing bolt (32) is threadedly connected to the top of the slider (31).

7. The graphite crucible lifting device for a single crystal furnace according to claim 1, characterized in that: The support base (1) has a pair of slide rails (5) fixedly connected to its side wall; the slide rails (5) have a connecting groove (51) in the middle; the lifting frame (16) is slidably connected to the connecting groove (51).

8. A graphite crucible lifting device for a single crystal furnace according to claim 7, characterized in that: A pair of scrapers (6) are fixedly connected to the top of the lifting frame (16); the scrapers (6) are slidably connected to the connecting groove (51) and the lead screw (15).

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