CN116219533A - Continuous feeding method for producing monocrystalline silicon by Czochralski method and monocrystalline furnace - Google Patents

Abstract

The invention discloses a continuous feeding method for producing monocrystalline silicon by a Czochralski method, which comprises the steps of adding a silicon raw material into a material conveying device, and vacuumizing the material conveying device and the material conveying device; assembling a material conveying device and a material feeding device, adding silicon raw materials into a crucible in a crystal growth furnace chamber, heating after the material feeding is finished to melt the silicon raw materials, and lifting a material feeding pipe out of the inner chamber of the single crystal furnace; starting the crystal pulling operation, and after the distance from the tail of the silicon rod to the crucible reaches a preset distance, enabling the feeding pipe to extend into the quartz crucible again, and adding silicon raw materials into the crystal growth furnace chamber by the feeding device and the feeding device to prepare a second crystal pulling rod; the vacuumized material conveying device can enable the silicon raw material to be in a dust-free and oxygen-free state, so that the purity of the silicon raw material is greatly improved. The invention also discloses a continuous feeding single crystal furnace for producing the single crystal silicon by the Czochralski method.

Description

Continuous feeding method for producing monocrystalline silicon by Czochralski method and monocrystalline furnace

Technical Field

The invention relates to the technical field of single crystal preparation, in particular to a continuous feeding method for producing single crystal silicon by a Czochralski method and a single crystal furnace.

Background

The process for producing monocrystalline silicon by the Czochralski method mainly comprises furnace disassembly, furnace loading, silicon melting, seeding, necking, shouldering, shoulder turning, isodiametric and ending. The purpose of disassembling the furnace is to take out the crystal, remove volatile matters in the furnace chamber, remove attachments, quartz fragments, graphite particles, graphite felt dust and other impurities on graphite parts such as electrodes, heaters, heat preservation covers and the like. The method comprises the steps of loading cleaned graphite devices into a single crystal furnace, adjusting the positions of the graphite devices, enabling a heater, a heat insulation cover and a graphite support bowl to be kept concentric, putting a quartz crucible into the graphite support bowl by a worker wearing clean thin film gloves, loading polysilicon into the quartz crucible, and then sequentially melting silicon, seeding, necking down, shouldering, shoulder turning, constant diameter and ending.

In order to improve the production efficiency of producing monocrystalline silicon by the Czochralski method, a secondary feeding device of a feeding pipe is disclosed, for example, the application number is 201320491528.4, and the phenomenon that the equipment utilization rate is low due to insufficient feeding caused by the fact that one half to two thirds of space of a quartz crucible is filled with molten silicon in the quartz crucible after the silicon raw material added into the quartz crucible is melted is solved. The 27 th section of the prior art clearly records that the charging tube secondary charging device and the seed chuck are convenient to exchange and install, namely, the charging tube secondary charging device is filled with silicon raw materials manually and then is added into a quartz crucible in the single crystal furnace through an auxiliary chamber, the silicon raw materials can be added again only after the crystal pulling is finished and the single crystal silicon rod is completely taken out from the auxiliary chamber, and the charging tube secondary charging devices are required to be filled with silicon raw materials manually, then the silicon raw materials in the charging tube secondary charging devices are sequentially added into the quartz crucible in the single crystal furnace through the auxiliary chamber, and vacuum pumping is required to be carried out on the auxiliary chamber after the charging tube secondary charging devices are placed in the auxiliary chamber each time, so that the charging mode of the charging tube secondary charging devices is still poor in efficiency.

Disclosure of Invention

In view of the foregoing, it is desirable to provide a continuous feeding method for producing silicon single crystal by the czochralski method, so as to solve the problem in the prior art that the feeding tube secondary feeding device filled with silicon raw material can be moved into the auxiliary chamber of the single crystal furnace only after the pulled crystal ingot is taken out from the auxiliary chamber of the single crystal furnace, and then the auxiliary chamber of the single crystal furnace is vacuumized and then the feeding tube secondary feeding device filled with silicon raw material is lowered to a preset position for feeding, so that the feeding time is long, resulting in low production efficiency of the single crystal.

Meanwhile, the continuous feeding single crystal furnace for producing the single crystal silicon by the Czochralski method is also provided.

A continuous feed process for producing single crystal silicon by the czochralski method, the process comprising the steps of:

s1, adding a silicon raw material into a storage bin of a material conveying device, and vacuumizing the material conveying device.

S2, installing a feeding device on the single crystal furnace, wherein the inner cavity of the feeding device is communicated with the inner cavity of the single crystal furnace, and the feeding port of the feeding device is sealed by a gate valve to vacuumize the feeding device.

S3, after a discharge hole of the material conveying device and a gate valve of the feeding device are mutually assembled and connected, the material conveying device adds silicon raw materials into a crucible in a crystal growth furnace chamber through the feeding device communicated with the single crystal furnace, the crucible is heated to enable the silicon raw materials to be molten, silicon melt is obtained, after the silicon melt reaches a preset height, the material conveying device stops feeding the silicon raw materials, and a feeding pipe of the feeding device is lifted to exit an inner cavity of the single crystal furnace.

S4, controlling a stretching device in the crystal growth furnace chamber to enable seed crystals at the bottom of the stretching device to descend to the liquid level of the silicon melt, and controlling the stretching device to lift the seed crystals according to a preset speed after preheating so as to grow monocrystalline silicon; after the ending of the monocrystalline silicon rod, the distance from the tail of the monocrystalline silicon rod to the crucible reaches a preset distance, a feeding pipe of the feeding device stretches into the quartz crucible again, the feeding device is controlled to convey the silicon raw material to the feeding device, the silicon raw material is continuously added into the crystal growth furnace chamber to prepare a second pulled crystal rod, and the feeding pipe of the feeding device is purged by high-purity argon in an auxiliary mode, so that continuous feeding is prevented from being affected by heated adhesion of the feeding pipe and the falling silicon raw material.

S5, after the silicon raw materials in the storage bin are used up, opening the storage bin, loading the silicon raw materials again, sealing the storage bin after the silicon raw materials are added, and repeating the steps S1 to S4 for producing monocrystalline silicon.

Preferably, the material conveying device is arranged outside the single crystal furnace and detachably connected with the feeding device, and the material conveying device is a closed cavity.

Preferably, the feeding device is arranged on a furnace cover of the single crystal furnace, an inner cavity of the feeding device is communicated with an inner cavity of the single crystal furnace, and after the single crystal furnace is vacuumized, the vacuum degree of the inner cavity of the feeding device is the same as that of the inner cavity of the single crystal furnace.

The utility model provides a continuous feeding single crystal furnace for producing monocrystalline silicon by Czochralski method, including main furnace body, feeding device, evacuation pump and argon gas circulation subassembly, set up feeding device on the bell of main furnace body, feeding device's discharge end and feeding device's feed end dismantle the connection, the vacuum pump is linked together through first butterfly valve and main furnace body and is used for carrying out the evacuation to the inner chamber of main furnace body, the vacuum pump is linked together through second butterfly valve and feeding device and is used for carrying out the evacuation to the inner chamber of feeding device, argon gas entering end setting of argon gas circulation subassembly is in the laryngeal department of main furnace body, argon gas recovery end setting of argon gas circulation subassembly is in the bottom of main furnace body; the feeding device comprises a corrugated pipe, a feeding pipe and a lifting assembly, wherein the corrugated pipe is a welded corrugated pipe, a sealing ring is arranged at the lower end of the corrugated pipe for being in sealing connection with a feeding port of a furnace cover of a main furnace body, the feeding pipe is inserted into the corrugated pipe and is in sealing connection with the upper end of the corrugated pipe by a first flange, a closed bin is arranged at the upper end of the corrugated pipe, a gate valve is arranged on the closed bin, an opening at the upper end of the feeding pipe is close to the gate valve and is positioned right below the gate valve, the lower end of the feeding pipe passes through the corrugated pipe and the interior of the single crystal furnace to be communicated, the closed bin and the feeding pipe form a silicon material feeding channel, the lifting assembly is fixedly connected with the first flange, and the lifting assembly drives the first flange to extend the lower end of the feeding pipe into a quartz crucible in the single crystal furnace or withdraw from the single crystal furnace in the up-down moving process; the conveying device comprises a storage bin and a conveying assembly, wherein a discharge hole of the storage bin is formed in the conveying assembly so that silicon raw materials in the storage bin enter the conveying assembly, the conveying assembly comprises a containing tube and a conveyor, a feeding hole is formed in the top side wall of the containing tube, the discharge hole of the storage bin is in butt joint with the feeding hole of the containing tube, the conveyor is arranged in the containing tube, the discharge hole of the storage bin is located right above the conveyor so that the silicon raw materials output from the storage bin fall onto a belt of the conveyor, a gate valve and the containing tube are detached and connected, and the front end of the conveyor stretches out of the containing tube to pass through the opened gate valve to be located right above the feeding tube.

Preferably, the lifting assembly comprises a supporting frame, a motor and a screw rod, wherein the lower end of the supporting frame is arranged at the charging hole of the single crystal furnace, the motor is arranged at the upper end of the supporting frame, the output end of the motor is fixedly connected with the upper end of the screw rod, the lower end rotating roller of the screw rod is connected to the supporting frame, a sliding part is arranged on the supporting frame, a threaded hole is formed in the sliding part, the threaded hole of the sliding part and the external threads of the screw rod are matched with each other, two sides of the first flange are respectively provided with a connecting part, each connecting part is mutually fixed with the sliding part, the screw rod drives the sliding part to move upwards or downwards relative to the supporting frame in the rotating process driven by the motor, and the sliding part drives the first flange to move along with the sliding part in the upward or downward moving process of the supporting frame, and the first flange drives the closed bin and the charging pipe to move up and down along the supporting frame.

Preferably, the feeding pipe comprises a material receiving part and a guiding part, the material receiving part is of an open structure, the lower end of the material receiving part and the upper end of the guiding part are integrally formed, a first flange is arranged at the joint of the material receiving part and the guiding part, the guiding part passes through the first flange and then is arranged on the first flange, the material receiving part is arranged in the closed bin, the upper end opening of the material receiving part is close to the silicon material inlet of the closed bin and is positioned below the silicon material inlet, and the lower end discharge opening of the guiding part is arranged in an inclined shape.

Preferably, the storage bin comprises an outer shell and a storage container, the lower part of the outer shell is gradually reduced from top to bottom, a discharge hole is formed in the lowest end of the lower part of the outer shell, the upper end of the storage container is connected with the side wall of the outer shell, a plurality of discharge holes are formed in the bottom of the storage container, a vibrator is arranged on the storage container and located at the bottom of the storage container or near the bottom of the storage container, and the vibrator works to enable the storage container to shake so that silicon raw materials in the storage container fall into the outer shell from the discharge holes.

Preferably, hold the pipe and be square pipe, hold the one end of pipe and set up the closing plate body, hold and respectively set up a guide rail on the both sides wall of pipe, the both sides of conveyer set up a plurality of gyro wheels, the gyro wheel of conveyer one side stretches into in a guide rail, the gyro wheel of conveyer opposite side stretches into in another guide rail, the rear end of conveyer sets up flexible subassembly, flexible subassembly's stiff end and closing plate body fixed connection, flexible subassembly's flexible end and the rear end fixed connection of conveyer, flexible subassembly promotes or the pulling conveyer and removes the front end that makes the conveyer from holding the pipe along the guide rail and stretch out, the gyro wheel rolls along the guide rail and makes the conveyer remove along the guide rail more easily.

Preferably, the conveyer includes the support body, a plurality of backing rolls, power roller and belt, a plurality of gyro wheels are laid in the both sides of support body, power roller and a plurality of backing rolls are installed in the support body, the belt twines around power roller and a plurality of backing rolls, the belt is the tetrafluoro material preparation and forms, power roller work drive belt rotates around power roller and a plurality of backing rolls, the lateral surface both sides of belt respectively set up a flexible separation blade, the flexible separation blade is formed by the tetrafluoro material preparation of flexibility, the flexible separation blade encircles the belt round setting, set up connecting portion between two flexible separation blades, connecting portion traction two flexible separation blades prevent that the flexible separation blade from receiving the extrusion of silicon raw materials outwards empting.

Preferably, the rear end of the accommodating pipe is sealed, the front end of the accommodating pipe is provided with the isolation valve, the accommodating pipe and the storage bin form a sealed communication cavity after the isolation valve is closed, the front end of the conveyor conveniently penetrates through the isolation valve after the isolation valve is opened, the silicon raw material on the belt of the conveyor is added into the container of the feeding device, and the flange of the isolation valve and the flange of the gate valve are flanges of the same specification, so that the isolation valve and the gate valve can be successfully butted to complete sealing connection; the second flange is arranged on the inner wall of the outer shell, the second flange is close to the upper end of the outer shell, the third flange is arranged on the outer wall of the storage container, the third flange is close to the upper end of the storage container, a plurality of first through holes are formed in the second flange, a plurality of second through holes are formed in the third flange, the number of the first through holes is consistent with that of the second through holes, a spring is placed between the corresponding first through holes and the second through holes, the spring is compressed by a proper compression amount after sequentially penetrating through the first through holes, the spring and the second through holes, the storage container is installed in the outer shell, the vibrator works to enable the storage container to shake, the shaking amount of the storage container is guaranteed under the action of the bolts and the springs, the outer wall of the storage container cannot touch the outer wall of the outer shell, and smooth continuous emission of silicon raw materials by the storage container is guaranteed.

In the continuous feeding method for producing the monocrystalline silicon by the Czochralski method, the silicon raw material is added into a feeding device outside the monocrystalline furnace and vacuumized; vacuumizing a charging device arranged on the single crystal furnace; after a discharge hole of a material conveying device and a gate valve of a feeding device are mutually assembled and connected, the material conveying device adds silicon raw materials into a crucible in a crystal growth furnace chamber through the feeding device communicated with the single crystal furnace, the crucible is heated after feeding is finished to enable the silicon raw materials to be melted, and a feeding pipe of the feeding device is lifted to exit from the inner chamber of the single crystal furnace; lifting seed crystals according to a preset speed by controlling a stretching device in the crystal growth furnace chamber so as to grow monocrystalline silicon; after the ending of the monocrystalline silicon rod, after the distance from the tail of the monocrystalline silicon rod to the crucible reaches a preset distance, a feeding pipe of a feeding device stretches into the quartz crucible again, a material conveying device is controlled to convey silicon raw materials to the feeding device, the silicon raw materials are continuously added into a crystal growth furnace chamber to prepare a second pulled crystal rod, and the feeding pipe of the feeding device is purged by high-purity argon in an auxiliary manner so as to prevent the feeding pipe and the falling silicon raw materials from being heated and adhered to influence continuous feeding; after the silicon raw material in the storage bin is used up, opening the storage bin to load the silicon raw material again, sealing the storage bin after the silicon raw material is added, and repeating the steps to carry out drawing production of monocrystalline silicon; because the outer shell and the storage container of the storage bin are arranged outside the single crystal furnace and still are positioned outside the single crystal furnace in the feeding process, the volumes of the outer shell and the storage container are larger to meet the requirement of polycrystalline silicon raw materials required by the corresponding single crystal furnace type multi-time single crystal pulling, so that enough silicon raw materials can be in dust-free and oxygen-free states after vacuumizing, the purity of the silicon raw materials is greatly improved.

Drawings

FIG. 1 is a flow chart of a continuous feed process for producing single crystal silicon by the Czochralski method.

FIG. 2 is a block diagram of a continuous feed single crystal furnace for producing silicon single crystal by Czochralski method.

FIG. 3 is a perspective view of a continuous feed single crystal furnace for producing silicon single crystal by Czochralski method in a feed state.

Fig. 4 is a top view of the charging device.

Fig. 5 is a cross-sectional view at A-A in fig. 4.

Fig. 6 is a left side view of the charging device.

FIG. 7 is a top view of a continuous feed single crystal furnace for producing silicon single crystal by the Czochralski method in a feed state.

Fig. 8 is a cross-sectional view at B-B in fig. 7.

Fig. 9 is a cross-sectional view at C-C in fig. 7.

Fig. 10 is a cross-sectional view of the charging device after being raised and when not charging.

Fig. 11 is a perspective view of the charging device after being raised and when not charging.

Fig. 12 is a front view of the feeder.

Fig. 13 is a perspective sectional view of fig. 12 at D-D.

Fig. 14 is a top view of the feeder.

Fig. 15 is a perspective sectional view at E-E in fig. 14.

Fig. 16 is a perspective view of the conveyor.

Fig. 17 is an enlarged view at F in fig. 13.

In the figure: the main furnace body 10, the furnace cover 11, the throat 12, the charging device 20, the bellows 21, the charging pipe 22, the receiving portion 221, the guiding portion 222, the first flange 223, the lifting assembly 23, the supporting frame 231, the motor 232, the screw 233, the slider 234, the threaded hole 2341, the closed bin 24, the gate valve 25, the first flange 26, the connector 261, the second flange 27, the feeding device 30, the storage bin 31, the outer shell 311, the discharging port 3111, the cover 3112, the second flange 3113, the first through hole 3114, the storage container 312, the discharging hole 3121, the vibrator 3122, the third flange 3123, the second through hole 3124, the spring 313, the bolt 314, the conveying assembly 32, the receiving tube 321, the guide rail 3211, the sealing plate body 3212, the conveyor 322, the roller 3221, the frame 3222, the supporting roller 3223, the power roller 3224, the belt 3225, the telescopic assembly 3226, the isolation valve 323, the supporting frame 33, the slide 331, the pulley 3213, the vacuum pump 40, the argon gas circulation assembly 50, the first butterfly valve 60, and the second butterfly valve 70.

Detailed Description

The technical scheme and technical effects of the embodiments of the present invention are further described in detail below with reference to the accompanying drawings.

Referring to fig. 1 to 17, a continuous feeding method for producing single crystal silicon by the czochralski method, the method comprising the steps of:

s1, adding silicon raw materials into a storage bin 31 of the material conveying device 30, and vacuumizing the material conveying device 30.

S2, a charging device 20 is arranged on the single crystal furnace, the inner cavity of the charging device 20 is communicated with the inner cavity of the single crystal furnace, a feeding port of the charging device 20 is sealed by a gate valve 25, and the charging device 20 is vacuumized.

S3, after the discharge hole of the material conveying device 30 and the gate valve 25 of the feeding device 20 are mutually assembled and connected, the material conveying device 30 adds silicon raw materials into a crucible in a crystal growth furnace chamber through the feeding device 20 communicated with the single crystal furnace, the crucible is heated to melt the silicon raw materials to obtain silicon melt, after the silicon melt reaches a preset height, the material conveying device 30 stops feeding the silicon raw materials, and a feeding pipe 22 of the feeding device 20 is lifted out of the inner chamber of the single crystal furnace.

S4, controlling a stretching device in the crystal growth furnace chamber to enable seed crystals at the bottom of the stretching device to descend to the liquid level of the silicon melt, and controlling the stretching device to lift the seed crystals according to a preset speed after preheating so as to grow monocrystalline silicon; after the end of the ending of the monocrystalline silicon rod, after the distance from the tail of the monocrystalline silicon rod to the crucible reaches a preset distance, the feeding pipe 22 of the feeding device 20 stretches into the quartz crucible again, the feeding device 30 is controlled to convey the silicon raw material to the feeding device 20, the silicon raw material is continuously added into the crystal growth furnace chamber for preparing a second time for drawing the crystal rod, and the feeding pipe 22 of the feeding device 20 is purged by high-purity argon in an auxiliary mode, so that continuous feeding is prevented from being influenced by heated adhesion of the feeding pipe 22 and the falling silicon raw material.

S5, after the silicon raw materials in the storage bin 31 are used up, opening the storage bin 31 to be filled with the silicon raw materials again, sealing the storage bin 31 after the silicon raw materials are added, and repeating the steps S1 to S4 for producing monocrystalline silicon.

Further, the material conveying device 30 is disposed outside the single crystal furnace and detachably connected with the feeding device 20, and the material conveying device 30 is a closed cavity.

Further, the feeding device 20 is disposed on the furnace cover 11 of the single crystal furnace, the inner cavity of the feeding device 20 is communicated with the inner cavity of the single crystal furnace, and after the single crystal furnace is vacuumized, the vacuum degree of the inner cavity of the feeding device 20 is the same as that of the inner cavity of the single crystal furnace.

Referring to fig. 2 to 17, the present invention further provides a continuous feeding single crystal furnace for producing silicon single crystal by a czochralski method, which comprises a main furnace body 10, a feeding device 20, a feeding device 30, a vacuum pump 40 and an argon gas circulation assembly 50, wherein the feeding device 20 is arranged on a furnace cover 11 of the main furnace body 10, a discharging end of the feeding device 30 is detachably connected with a feeding end of the feeding device 20, the vacuum pump 40 is communicated with the main furnace body 10 through a first butterfly valve 60 to vacuumize an inner cavity of the main furnace body 10, the vacuum pump 40 is communicated with the feeding device 30 through a second butterfly valve 70 to vacuumize the inner cavity of the feeding device 30, an argon gas inlet end of the argon gas circulation assembly 50 is arranged at a throat 12 of the main furnace body 10, and an argon gas recovery end of the argon gas circulation assembly 50 is arranged at the bottom of the main furnace body 10; the feeding device 20 comprises a corrugated pipe 21, a feeding pipe 22 and a lifting assembly 23, wherein the corrugated pipe 21 is a welded corrugated pipe 21, a sealing ring is arranged at the lower end of the corrugated pipe 21 for being in sealing connection with a feed port of a furnace cover 11 of the main furnace body 10, the feeding pipe 22 is inserted into the corrugated pipe 21 and is in sealing connection with the upper end of the corrugated pipe 21 and the upper end of the feeding pipe 22 through a first flange 26, a closed bin 24 is arranged at the upper end of the corrugated pipe 21, a gate valve 25 is arranged on the closed bin 24, an upper end opening of the feeding pipe 22 is close to the gate valve 25 and is positioned under the gate valve 25, the lower end of the feeding pipe 22 is communicated with the inside of the single crystal furnace through the corrugated pipe 21, the closed bin 24 and the feeding pipe 22 form a silicon material feeding channel, the lifting assembly 23 is fixedly connected with the first flange 26, and the lifting assembly 23 drives the lower end of the feeding pipe 22 to extend into a quartz crucible in the single crystal furnace or withdraw from the single crystal furnace in the up-down moving process of the first flange 26; the lifting assembly 23 works to enable the first flange 26 to move up and down, the first flange 26 enables the corrugated tube 21 to shrink gradually in the downward moving process, the first flange 26 pushes the charging tube 22 to be inserted into the single crystal furnace gradually, the lower end of the charging tube 22 is gradually close to the molten silicon liquid level in the quartz crucible to finish the state of preparing to add silicon materials, after the charging is finished, the lifting assembly 23 drives the first flange 26 to stretch gradually in the upward moving process, the first flange 26 pulls the charging tube 22 to be gradually far away from the quartz crucible, and the lower end of the charging tube 22 is pulled out of the single crystal furnace to facilitate the preparation of the crystal furnace for the re-pulling process. The conveying device 30 comprises a storage bin 31 and a conveying assembly 32, wherein a discharge hole of the storage bin 31 is formed in the conveying assembly 32 so that silicon raw materials in the storage bin 31 enter the conveying assembly 32, the conveying assembly 32 comprises a containing pipe 321 and a conveyor 322, a feeding hole is formed in the top side wall of the containing pipe 321, the discharge hole of the storage bin 31 is in butt joint with the feeding hole of the containing pipe 321, the conveyor 322 is arranged in the containing pipe 321, the discharge hole of the storage bin 31 is located right above the conveyor 322 so that the silicon raw materials output from the storage bin 31 fall onto a belt 3225 of the conveyor 322, a gate valve 25 is connected with the containing pipe 321 in a detached mode, and the front end of the conveyor 322 extends from the containing pipe 321 to pass through the opened gate valve 25 to be located right above the feeding pipe 22.

Further, the lifting assembly 23 comprises a supporting frame 231, a motor 232 and a screw 233, wherein the lower end of the supporting frame 231 is installed at the charging hole of the furnace cover 11 of the main furnace body 10, the motor 232 is installed at the upper end of the supporting frame 231, the output end of the motor 232 is fixedly connected with the upper end of the screw 233, the lower end of the screw 233 is rotatably connected to the supporting frame 231, a sliding member 234 is arranged on the supporting frame 231, a threaded hole 2341 is arranged on the sliding member 234, the threaded hole 2341 of the sliding member 234 is matched with the external thread of the screw 233, two sides of the first flange 26 are respectively provided with a connecting member 261, each connecting member 261 is mutually fixed with the sliding member 234, the screw 233 drives the sliding member 234 to move upwards or downwards relative to the supporting frame 231 in the driving process of moving upwards or downwards relative to the supporting frame 231, and the first flange 26 drives the sealing bin 24 and the charging pipe 22 to move upwards or downwards along the supporting frame 231 in the moving process.

Further, the feeding tube 22 comprises a receiving portion 221 and a guiding portion 222, the receiving portion 221 is of an open structure, the lower end of the receiving portion 221 and the upper end of the guiding portion 222 are integrally formed, a first flange 223 is arranged at the joint of the receiving portion 221 and the guiding portion 222, the guiding portion 222 penetrates through the first flange 26 and then is arranged on the first flange 26, the receiving portion 221 is placed in the closed bin 24, an upper end opening of the receiving portion 221 is close to a silicon material inlet of the closed bin 24 and is located below the silicon material inlet, and a lower end discharging opening of the guiding portion 222 is arranged in an inclined mode. The receiving portion 221 is specifically a hollow cone structure. The lower extreme of bellows 21 sets up second flange 27, and the lower terminal surface and the up end sealing connection of second flange 27 of bellows 21, the lower terminal surface and the bottom plate up end sealing connection of support frame 231 of second flange 27, the bottom plate lower terminal surface and the flange sealing connection on the single crystal growing furnace bell 11 of support frame 231.

Further, the storage bin 31 includes an outer shell 311 and a storage container 312, the lower portion of the outer shell 311 gradually shrinks from top to bottom, the lowest end of the outer shell 311 is provided with a discharge port 3111, the discharge port 3111 is arranged at the lowest end of the lower portion of the outer shell 311, the upper end of the storage container 312 is connected with the side wall of the outer shell 311, the bottom of the storage container 312 is provided with a plurality of discharge holes 3121, the storage container 312 is provided with a vibrator 3122, the vibrator 3122 is located at the bottom of the storage container 312 or near the bottom, and the vibrator 3122 works to shake the storage container 312 so that silicon materials in the storage container 312 fall into the outer shell 311 from the discharge holes 3121. The top of the outer shell 311 is provided with a cover 3112, silicon raw materials can be added into the storage container 312 by opening the cover 3112, a closed container is formed in the outer shell 311 after the cover 3112 is tightly covered, the accommodating pipe 321 is provided with a second butterfly valve 70, in this embodiment, the second butterfly valve 70 is arranged on the accommodating pipe 321, in other embodiments, the second butterfly valve 70 can also be arranged on the outer shell 311, and the closed container formed by the outer shell 311 and the accommodating pipe 321 can be vacuumized through the second butterfly valve 70.

Further, the accommodating tube 321 is a square tube, one end of the accommodating tube 321 is provided with a sealing plate body 3212, two side walls of the accommodating tube 321 are respectively provided with a guide rail 3211, two sides of the conveyor 322 are provided with a plurality of rollers 3221, one roller 3221 on one side of the conveyor 322 stretches into one guide rail 3211, the roller 3221 on the other side of the conveyor 322 stretches into the other guide rail 3211, the rear end of the conveyor 322 is provided with a telescopic assembly 3226, the fixed end of the telescopic assembly 3226 is fixedly connected with the sealing plate body 3212, the telescopic end of the telescopic assembly 3226 is fixedly connected with the rear end of the conveyor 322, and the telescopic assembly 3226 pushes or pulls the conveyor 322 to move along the guide rail 3211 in the telescopic process so that the front end of the conveyor 322 stretches out from the accommodating tube 321, and the roller 3221 rolls along the guide rail 3211 more easily so that the conveyor 322 moves along the guide rail 3211.

Further, the conveyor 322 includes a frame 3222, a plurality of supporting rollers 3223, a power roller 3224 and a belt 3225, a plurality of rollers 3221 are arranged on two sides of the frame 3222, the power roller 3224 and the plurality of supporting rollers 3223 are installed in the frame 3222, the belt 3225 is wound around the power roller 3224 and the plurality of supporting rollers 3223, the belt 3225 is made of a tetrafluoro material, the power roller 3224 drives the belt 3225 to rotate around the power roller 3224 and the plurality of supporting rollers 3223, two sides of the outer side surface of the belt 3225 are respectively provided with a flexible baffle plate, the flexible baffle plates are made of a flexible tetrafluoro material, the flexible baffle plates are arranged around the belt 3225 in a circle, a connecting part is arranged between the two flexible baffle plates, and the connecting part pulls the two flexible baffle plates to prevent the flexible baffle plates from being extruded by silicon raw materials to outwards topple. The power roller 3224 may be connected to a motor to power it. Or power roller 3224 itself powers belt 3225 to circulate belt 3225 around support roller 3223 and power roller 3224.

Further, the rear end of the accommodating pipe 321 is sealed, an isolation valve 323 is installed at the front end of the accommodating pipe 321, the accommodating pipe 321 and the storage bin 31 form a sealed communication cavity after the isolation valve 323 is closed, the front end of the conveyor 322 conveniently penetrates through the isolation valve 323 to add silicon raw materials on a belt 3225 of the conveyor 322 into a container of the feeding device 20 after the isolation valve 323 is opened, and a flange of the isolation valve 323 and a flange of the gate valve 25 are flanges of the same specification, so that the isolation valve 323 and the gate valve 25 can be successfully abutted to complete sealing connection; the second flange 3113 is arranged on the inner wall of the outer shell 311, the second flange 3113 is close to the upper end of the outer shell 311, the third flange 3123 is arranged on the outer wall of the storage container 312, the third flange 3123 is close to the upper end of the storage container 312, the second flange 3113 is provided with a plurality of first through holes 3114, the third flange 3123 is provided with a plurality of second through holes 3124, the number of the first through holes 3114 is consistent with the number of the second through holes 3124, a spring 313 is arranged between the corresponding first through holes 3114 and the second through holes 3124, the bolt 314 sequentially passes through the first through holes 3114, the spring 313 and the second through holes 3124, the spring 313 is compressed by a proper compression amount, the storage container 312 is installed in the outer shell 311, the vibrator 3122 works to enable the storage container 312 to shake, the shake amount of the storage container 312 is ensured under the action of the bolts 314 and the springs 313, the outer wall of the storage container 312 cannot touch the outer wall of the outer shell 311, and the continuous discharge of silicon raw materials from the storage container 312 is ensured.

Further, the material conveying device 30 further includes a support 33, at least two parallel sliding rails 331 are disposed on an upper end surface of the support 33, a plurality of pulleys 3213 are installed on a lower end surface of the accommodating pipe 321, at least two pulleys 3213 are disposed on a lower end surface of the accommodating pipe 321 side by side, a row number formed by the pulleys 3213 is consistent with a number of the sliding rails 331, at least two pulleys 3213 are disposed on each sliding rail 311, a locking member is disposed on one of the pulleys 3213, and the pulleys 3213 can be locked by rotating the locking member, so that the storage bin 31 and the conveying assembly 32 are stopped on the support 33 and kept motionless.

When the silicon raw material needs to be added into the quartz crucible in the single crystal furnace, the continuous feeding single crystal furnace for producing the single crystal silicon by the Czochralski method is in an un-fed state, as shown in fig. 11, the gate valve 25 is in a closed state, the feeding device 20 is communicated with the inside of the single crystal furnace, firstly, the lifting component 23 of the feeding device 20 is required to work to gradually descend the feeding pipe 22, the closed bin 24 and the gate valve 25 together, at the moment, the top end of the corrugated pipe 21 gradually descends and the lower end of the corrugated pipe 21 is kept motionless in the descending process, namely, the corrugated pipe 21 is gradually shortened due to compression, the lower end of the feeding pipe 22 is gradually inserted into the single crystal furnace, when the lifting component 23 works to enable the height of the gate valve 25 to be identical with the height of the isolation valve 323, the conveying component 32 is pushed to enable the isolation valve 323 to be abutted against the gate valve 25, and then the gate valve 25 and the isolation valve 323 are in sealing connection by bolts and sealing gaskets, at this time, the lower end of the feeding tube 22 is already inserted into the quartz crucible in the single crystal furnace, as the vacuum degree of the preset target value is already pumped by the vacuum pump 40 in the material conveying device 30 and the single crystal furnace, the isolation valve 323 and the gate valve 25 are opened, the telescopic assembly 3226 is operated to push the conveyor 322 to move along the guide rail 3211, so that the front end of the conveyor 322 extends out of the isolation valve 323 and enters the closed bin 24 through the gate valve 25, at this time, the front end of the conveyor 322 is positioned right above the material receiving portion 221, the vibrator 3122 and the conveyor 322 are opened to operate, so that the silicon raw material in the material storage container 312 gradually falls down to the material outlet 3111, the falling silicon raw material is discharged onto the belt 3225 of the conveyor 322 by the material outlet 3111, the operating belt 3225 continuously discharges the silicon raw material into the material receiving portion 221, the silicon raw material entering the material receiving portion 221 enters the quartz crucible along the guide portion 222, the mechanical feeding of the silicon raw material is realized by the continuous feeding process, the efficiency of charging is improved, meanwhile, as the stored silicon raw material is in a negative pressure state in the storage container 312, the silicon raw material is further prevented from being oxidized in the negative pressure state, and the charging pipe 22 is cooled by the argon circulation assembly 50 in the charging process, so that the continuous charging is prevented from being influenced by the heated adhesion of the charging pipe and the falling silicon raw material; when the first charging is completed, the telescopic assembly 3226 is operated to pull the conveyor 322 to move along the guide rail 3211 so that the front end of the conveyor 322 is withdrawn from the closed bin 24, the gate valve 25 and the isolation valve 323 in sequence and enters the accommodating pipe 321, the isolation valve 323 and the gate valve 25 are closed, bolts and gaskets for connecting the gate valve 25 and the isolation valve 323 are detached, the isolation valve 323 and the gate valve 25 are separated from each other by the moving conveying assembly 32, the charging pipe 22, the closed bin 24 and the gate valve 25 are gradually lifted by the lifting assembly 23, the top end of the corrugated pipe 21 is gradually lifted while the lower end of the corrugated pipe 21 is kept still in the lifting process, namely, the corrugated pipe 21 is gradually elongated due to stretching, the lower end of the charging pipe 22 is gradually withdrawn from the single crystal furnace, and finally the lower end of the charging pipe 22 is withdrawn to the position shown in fig. 10, the continuous charging single crystal furnace for producing single crystal silicon by the Czochralski method is completed from the non-charging of silicon raw material to the first time, when the single crystal furnace finishes the first time of crystal bar drawing, after the crystal bar rises to a certain height, the lifting component 23 is adopted to work to descend the feeding pipe 22 into the quartz crucible again for feeding again, because the outer shell 311 and the storage container 312 of the storage bin 31 are arranged outside the single crystal furnace and still are positioned outside the single crystal furnace in the feeding process, the volumes of the outer shell 311 and the storage container 312 can be set larger to meet the polysilicon raw materials required by the multiple times of single crystal drawing corresponding to the furnace type of the single crystal furnace, the silicon raw materials are not required to be manually added by adopting the feeding method and the single crystal furnace, the silicon raw materials are not required to be added to the quartz crucible in the single crystal furnace without waiting for the pulled crystal bar to completely exit the single crystal furnace, the aim of shortening the production period of single crystal drawing is achieved, the production efficiency of the single crystal is improved, meanwhile, the energy waste caused by heat dissipation in the single crystal furnace due to repeated furnace disassembly is reduced.

Claims (10)

1. A continuous feeding method for producing monocrystalline silicon by a Czochralski method comprises the following steps of:

s1, adding a silicon raw material into a storage bin of a material conveying device, and vacuumizing the material conveying device;

s2, installing a feeding device on the single crystal furnace, wherein the inner cavity of the feeding device is communicated with the inner cavity of the single crystal furnace, and the feeding port of the feeding device is sealed by a gate valve to vacuumize the feeding device;

s3, after a discharge hole of a material conveying device and a gate valve of a feeding device are mutually assembled and connected, the material conveying device adds silicon raw materials into a crucible in a crystal growth furnace chamber through the feeding device communicated with the single crystal furnace, the crucible is heated to enable the silicon raw materials to be molten, silicon melt is obtained, after the silicon melt reaches a preset height, the material conveying device stops feeding the silicon raw materials, and a feeding pipe of the feeding device is lifted out of an inner cavity of the single crystal furnace;

s4, controlling a stretching device in the crystal growth furnace chamber to enable seed crystals at the bottom of the stretching device to descend to the liquid level of the silicon melt, and controlling the stretching device to lift the seed crystals according to a preset speed after preheating so as to grow monocrystalline silicon; after the ending of the monocrystalline silicon rod, after the distance from the tail of the monocrystalline silicon rod to the crucible reaches a preset distance, a feeding pipe of a feeding device stretches into the quartz crucible again, a material conveying device is controlled to convey silicon raw materials to the feeding device, the silicon raw materials are continuously added into a crystal growth furnace chamber to prepare a second pulled crystal rod, and the feeding pipe of the feeding device is purged by high-purity argon in an auxiliary manner so as to prevent the feeding pipe and the falling silicon raw materials from being heated and adhered to influence continuous feeding;

s5, after the silicon raw materials in the storage bin are used up, opening the storage bin, loading the silicon raw materials again, sealing the storage bin after the silicon raw materials are added, and repeating the steps S1 to S4 for producing monocrystalline silicon.

2. The continuous feeding method for producing single crystal silicon by the Czochralski method as claimed in claim 1, wherein: the material conveying device is arranged outside the single crystal furnace and detachably connected with the feeding device, and the material conveying device is a closed cavity.

3. The continuous feeding method for producing single crystal silicon by the Czochralski method as claimed in claim 1, wherein: the charging device is arranged on the furnace cover of the single crystal furnace, the inner cavity of the charging device is communicated with the inner cavity of the single crystal furnace, and after the single crystal furnace is vacuumized, the vacuum degree of the inner cavity of the charging device is the same as that of the inner cavity of the single crystal furnace.

4. A continuous feeding single crystal furnace for producing single crystal silicon by a Czochralski method is characterized in that: the device comprises a main furnace body, a feeding device, a material conveying device, a vacuumizing pump and an argon gas circulation assembly, wherein the feeding device is arranged on a furnace cover of the main furnace body, a discharge end of the material conveying device is detachably connected with a feed end of the feeding device, the vacuum pump is communicated with the main furnace body through a first butterfly valve and is used for vacuumizing an inner cavity of the main furnace body, the vacuum pump is communicated with the material conveying device through a second butterfly valve and is used for vacuumizing the inner cavity of the material conveying device, an argon gas inlet end of the argon gas circulation assembly is arranged at a throat of the main furnace body, and an argon gas recovery end of the argon gas circulation assembly is arranged at the bottom of the main furnace body; the feeding device comprises a corrugated pipe, a feeding pipe and a lifting assembly, wherein the corrugated pipe is a welded corrugated pipe, a sealing ring is arranged at the lower end of the corrugated pipe for being in sealing connection with a feeding port of a furnace cover of a main furnace body, the feeding pipe is inserted into the corrugated pipe and is in sealing connection with the upper end of the corrugated pipe by a first flange, a closed bin is arranged at the upper end of the corrugated pipe, a gate valve is arranged on the closed bin, an opening at the upper end of the feeding pipe is close to the gate valve and is positioned right below the gate valve, the lower end of the feeding pipe passes through the corrugated pipe and the interior of the single crystal furnace to be communicated, the closed bin and the feeding pipe form a silicon material feeding channel, the lifting assembly is fixedly connected with the first flange, and the lifting assembly drives the first flange to extend the lower end of the feeding pipe into a quartz crucible in the single crystal furnace or withdraw from the single crystal furnace in the up-down moving process; the conveying device comprises a storage bin and a conveying assembly, wherein a discharge hole of the storage bin is formed in the conveying assembly so that silicon raw materials in the storage bin enter the conveying assembly, the conveying assembly comprises a containing tube and a conveyor, a feeding hole is formed in the top side wall of the containing tube, the discharge hole of the storage bin is in butt joint with the feeding hole of the containing tube, the conveyor is arranged in the containing tube, the discharge hole of the storage bin is located right above the conveyor so that the silicon raw materials output from the storage bin fall onto a belt of the conveyor, a gate valve and the containing tube are detached and connected, and the front end of the conveyor stretches out of the containing tube to pass through the opened gate valve to be located right above the feeding tube.

5. The continuous feed single crystal furnace for producing single crystal silicon by the Czochralski method as claimed in claim 4, wherein: the lifting assembly comprises a supporting frame, a motor and a screw rod, wherein the lower end of the supporting frame is arranged at a charging hole of the single crystal furnace, the motor is arranged at the upper end of the supporting frame, the output end of the motor is fixedly connected with the upper end of the screw rod, a rotating roller at the lower end of the screw rod is connected to the supporting frame, a sliding part is arranged on the supporting frame, threaded holes are formed in the sliding part, the threaded holes of the sliding part and the external threads of the screw rod are matched with each other, two sides of the first flange are respectively provided with a connecting part, each connecting part is mutually fixed with the sliding part, the screw rod drives the sliding part to move upwards or downwards relative to the supporting frame in the process of rotating under the driving of the motor, and the sliding part drives the first flange to move along the sliding part together in the process of moving upwards or downwards, and the first flange drives the closed bin and the charging pipe to move up and down along the supporting frame.

6. The continuous feed single crystal furnace for producing single crystal silicon by the Czochralski method as claimed in claim 4, wherein: the charging pipe comprises a material receiving part and a guiding part, wherein the material receiving part is of an open structure, the lower end of the material receiving part and the upper end of the guiding part are integrally formed, a first flange is arranged at the joint of the material receiving part and the guiding part, the guiding part passes through the first flange and then is arranged on the first flange, the material receiving part is arranged in a closed bin, an upper end opening of the material receiving part is close to a silicon material inlet of the closed bin and is positioned below the silicon material inlet, and a lower end discharging opening of the guiding part is arranged in an inclined shape.

7. The continuous feed single crystal furnace for producing single crystal silicon by the Czochralski method as claimed in claim 4, wherein: the storage bin comprises an outer shell and a storage container, the lower part of the outer shell is gradually reduced from top to bottom, a discharge hole is formed in the lowest end of the lower part of the outer shell, the upper end of the storage container is connected with the side wall of the outer shell, a plurality of discharge holes are formed in the bottom of the storage container, a vibrator is arranged on the storage container and located at the bottom of the storage container or near the bottom of the storage container, and the vibrator works to enable the storage container to shake so that silicon raw materials in the storage container fall into the outer shell from the discharge holes.

8. The continuous feed single crystal furnace for producing single crystal silicon by the Czochralski method as claimed in claim 4, wherein: the holding pipe is square pipe, holds the one end of pipe and sets up the closing plate body, holds and respectively sets up a guide rail on the both sides wall of pipe, and the both sides of conveyer set up a plurality of gyro wheels, and in the gyro wheel of conveyer one side stretched into a guide rail, the gyro wheel of conveyer opposite side stretched into another guide rail in, the rear end of conveyer set up flexible subassembly, flexible subassembly's stiff end and closing plate body fixed connection, flexible subassembly's flexible end and the rear end fixed connection of conveyer, flexible subassembly promote or the pulling conveyer moves along the guide rail and makes the front end of conveyer stretch out from the holding pipe, and the gyro wheel rolls along the guide rail and makes the conveyer move along the guide rail more easily.

9. The continuous feed single crystal furnace for producing single crystal silicon by the Czochralski method of claim 8, wherein: the conveyer includes the support body, a plurality of backing rolls, power roller and belt, a plurality of gyro wheels are laid in the both sides of support body, power roller and a plurality of backing rolls are installed in the support body, the belt twines around power roller and a plurality of backing rolls, the belt is the tetrafluoro material preparation and forms, power roller work drive belt rotates round power roller and a plurality of backing rolls, the lateral surface both sides of belt respectively set up a flexible separation blade, the flexible separation blade is formed by the tetrafluoro material preparation of flexibility, the flexible separation blade encircles the belt round setting, set up connecting portion between two flexible separation blades, connecting portion traction two flexible separation blades prevent that the flexible separation blade from receiving the extrusion of silicon raw materials outwards empting.

10. The continuous feed single crystal furnace for producing single crystal silicon by the Czochralski method as claimed in claim 4, wherein: the rear end of the accommodating pipe is sealed, the front end of the accommodating pipe is provided with an isolation valve, the accommodating pipe and the storage bin form a sealed communication cavity after the isolation valve is closed, the front end of the conveyor conveniently penetrates through the isolation valve after the isolation valve is opened, silicon raw materials on a belt of the conveyor are added into a container of the feeding device, and flanges of the isolation valve and a flange of the gate valve are flanges of the same specification, so that the isolation valve and the gate valve can be successfully butted to complete sealing connection; the second flange is arranged on the inner wall of the outer shell, the second flange is close to the upper end of the outer shell, the third flange is arranged on the outer wall of the storage container, the third flange is close to the upper end of the storage container, a plurality of first through holes are formed in the second flange, a plurality of second through holes are formed in the third flange, the number of the first through holes is consistent with that of the second through holes, a spring is placed between the corresponding first through holes and the second through holes, the spring is compressed by a proper compression amount after sequentially penetrating through the first through holes, the spring and the second through holes, the storage container is installed in the outer shell, the vibrator works to enable the storage container to shake, the shaking amount of the storage container is guaranteed under the action of the bolts and the springs, the outer wall of the storage container cannot touch the outer wall of the outer shell, and smooth continuous emission of silicon raw materials by the storage container is guaranteed.

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