CN117865161A - Silicon core production equipment and production method thereof - Google Patents

Abstract

The application provides silicon core production equipment and a production method thereof, and relates to the technical field of silicon core production. The silicon core production equipment comprises at least one furnace body, an induction heater, at least one crucible, a preheater and a lifter, wherein the furnace body comprises furnace walls, furnace walls are enclosed to form a furnace chamber, the induction heater is installed in the furnace chamber, one side of the induction heater is in sliding connection with the furnace walls, the induction heater is provided with a through hole, the crucible is penetrated by the induction heater, the preheater is distributed on the periphery of the crucible, the lifter is correspondingly arranged with the crucible, and each end part of the crucible is connected with one lifter. The silicon core with different diameters can be directly generated, cutting loss is not needed, the generation cost is lower, and the generation efficiency is improved.

Description

Silicon core production equipment and production method thereof

Technical Field

The application relates to the technical field of silicon core production, in particular to silicon core production equipment and a silicon core production method.

Background

Silicon is one of the most important base materials of modern technology. At present, an improved Siemens method is widely adopted for preparing high-purity silicon polycrystalline silicon, and a silicon core is used in the reduction process of the polycrystalline silicon. The silicon core can be divided into a zone-melting silicon core and a cutting silicon core according to different production processes. The zone-melting silicon core is obtained by drawing a round silicon core with a round cross section through a zone-melting process by utilizing a pre-prepared raw material rod in zone-melting equipment. The silicon core is cut by a straight-pulling silicon core rod with larger size through a diamond wire net, and a plurality of square silicon cores with small size and square cross section are obtained.

Compared with a round silicon core, the square silicon core has the advantages of large productivity, consistent size specification, low rod pouring rate of the reduction furnace and the like. The processing flow of cutting square silicon core mainly comprises the working procedures of head and tail removing, cutting, cone grinding, punching, cleaning, drying and the like, hidden cracks are easy to generate in the processing process, the working procedures are numerous, and the manufacturing cost is high. To this end, a silicon core production apparatus and a production method thereof are now provided.

Disclosure of Invention

In view of the above, the present application aims to provide a silicon core production device and a production method thereof, which aims to solve the technical problems of complex silicon core production process and large loss in the prior art.

In order to achieve the above purpose, the technical scheme adopted in the application is as follows:

in a first aspect, embodiments of the present application provide a silicon core production apparatus, including:

at least one furnace body comprising furnace walls enclosing a furnace chamber:

the induction heater is arranged in the furnace chamber, and one side of the induction heater is in sliding connection with the furnace wall;

at least one crucible, wherein the induction heater is provided with a through hole, and the crucible penetrates through the through hole of the induction heater;

the pre-heaters are distributed on the periphery of the crucible;

and the lifters are arranged corresponding to the crucibles, and the end part of each crucible is connected with one lifter.

In one embodiment of the first aspect, the silicon core production apparatus further includes a storage chamber connected to an end of the furnace body remote from the lifter.

In one embodiment of the first aspect, a plurality of discharging pipes are arranged on one side, connected with the furnace body, of the storage chamber, each discharging pipe corresponds to one crucible, and each discharging pipe is provided with a charging switch.

In one embodiment of the first aspect, an air inlet is formed at one end of the furnace body, which is close to the storage chamber, and an air outlet is formed at one side of the furnace body, which is far away from the storage chamber.

In one embodiment of the first aspect, the induction heater includes a plurality of split induction heaters and a bracket, the split induction heaters are all mounted on the bracket, and one side of the bracket is connected with the furnace wall.

In one embodiment of the first aspect, the furnace wall is provided with a lifting mechanism controlling lifting movement of the support within the furnace chamber.

In one embodiment of the first aspect, a heat shield is provided on a side of the induction heater adjacent to the preheater.

In one embodiment of the first aspect, the crucible comprises a plurality of petals, two adjacent petals are spliced with each other, and a cooling channel is arranged in the petals.

In one embodiment of the first aspect, the pre-heater includes an external heater and an internal heater, the external heater is framed on the outer side of the internal heater, one crucible is disposed in the internal heater, and a plurality of crucibles are disposed between the external heater and the internal heater.

In a second aspect, embodiments of the present application further provide a method for producing a silicon core, including:

the lifter drives the crucible to descend until the bottom of the crucible reaches a heating area of the preheater, polysilicon material is added into the crucible, the furnace chamber is vacuumized, and after the vacuum degree reaches a set value, high-purity inert gas is filled into the vacuum furnace chamber and an exhaust port is opened;

the preheating device heats the bottom of the crucible, and when the temperature of the polysilicon material rises to a set temperature, the heating is stopped;

the lifter drives the crucible to ascend until the bottom of the crucible is separated from the heating area range of the heater, and the induction heater is lowered to the corresponding area of the crucible for preheating treatment;

starting an induction heater for heating, adding the polycrystalline silicon material into the crucible after the existing polycrystalline silicon material in the crucible is completely melted, and lifting the induction heater synchronously during the feeding, wherein the polycrystalline silicon material below the induction heater is cooled and solidified until the growth of the silicon rod is completed;

and taking out the silicon rod, and carrying out mechanical processing, cleaning and drying on the silicon rod to obtain the silicon core.

Compared with the prior art, the beneficial effects of this application are: the application provides silicon core production equipment and a production method thereof, which can be used for directional solidification process production of silicon cores. The silicon core production equipment comprises at least one furnace body, an induction heater, at least one crucible, a pre-heater and a lifter, wherein the induction heater is installed in the furnace chamber of the furnace body, one side of the induction heater is connected with the furnace wall, the crucible penetrates through the induction heater, the pre-heater is distributed on the periphery of the crucible, and the lifter is connected with the end part of the crucible. Therefore, the lifting height of the crucible can be controlled by the lifter, and before directional solidification of the silicon core is generated, the bottom of the crucible is positioned in the heating range of the preheater, so that the silicon material at the bottom of the crucible is preheated, and the temperature of the silicon material can be increased to be capable of being subjected to induction heating. Then, the crucible is lifted to enable the silicon material reaching the induction heating temperature to be in the heating range of the induction heater, the silicon material is heated and melted, after the silicon material at the bottom of the crucible is melted, the cold silicon material is continuously added, meanwhile, the induction heater is lifted synchronously, and the silicon material below and far away from the induction heater is cooled and solidified until the complete silicon material is generated. The silicon core with different diameters can be directly generated, cutting loss is not needed, the generation cost is lower, and the generation efficiency is improved.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the embodiments will be briefly described below, it being understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered limiting the scope, and that other related drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 shows a schematic diagram of a silicon core manufacturing apparatus in accordance with some embodiments of the present application;

FIG. 2 shows a second schematic structural view of a silicon core manufacturing apparatus in some embodiments of the present application;

FIG. 3 illustrates a schematic diagram of an induction heater in some embodiments of the present application;

FIG. 4 illustrates a schematic diagram of a pre-heater in some embodiments of the present application;

FIG. 5 illustrates a second schematic diagram of a pre-heater in some embodiments of the present application;

FIG. 6 is a schematic view showing the structure of a crucible in some embodiments of the present application;

FIG. 7 illustrates a schematic structural view of a valve body in some embodiments of the present application;

FIG. 8 is a schematic diagram showing the layout structure of a furnace body of a silicon core production apparatus according to some embodiments of the present application;

fig. 9 illustrates a flow chart of a method of producing a silicon core in some embodiments of the present application.

Description of main reference numerals:

100-silicon core production equipment; 110-a furnace body; 111-furnace walls; 112-furnace chamber; 113-an air inlet; 114-an exhaust port; 120-an induction heater; 121-split induction heater; 122-a stent; 123-insulating panels; 130-crucible; 131-petals; 140-preheater; 141-an external heater; 142-an inner heater; 150-lifters; 160-a storage chamber; 161-bin body; 162-cover; 163-an extraction opening; 164-a feed inlet; 170-a discharge pipe; 180-charging switch.

Detailed Description

Embodiments of the present application are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals refer to the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary only for the purpose of explaining the present application and are not to be construed as limiting the present application.

In the description of the present application, it should be understood that the terms "center," "longitudinal," "transverse," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," etc. indicate orientations or positional relationships based on the orientation or positional relationships shown in the drawings, are merely for convenience in describing the present application and simplifying the description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be configured and operated in a particular orientation, and therefore should not be construed as limiting the present application.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present application, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.

In this application, unless specifically stated and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the terms in this application will be understood by those of ordinary skill in the art as the case may be.

In this application, unless expressly stated or limited otherwise, a first feature "up" or "down" a second feature may be the first and second features in direct contact, or the first and second features in indirect contact via an intervening medium. Moreover, a first feature being "above," "over" and "on" a second feature may be a first feature being directly above or obliquely above the second feature, or simply indicating that the first feature is level higher than the second feature. The first feature being "under", "below" and "beneath" the second feature may be the first feature being directly under or obliquely below the second feature, or simply indicating that the first feature is less level than the second feature.

The inventors of the present application have found that at present, an improved siemens process is commonly used to prepare high purity polysilicon, and that a silicon core is used in the reduction process of polysilicon. The silicon core in the reducing furnace can be divided into a zone-melting silicon core and a cutting silicon core according to different production processes. The zone-melting silicon core is a silicon core with the diameter of 7-12mm and the length of 2500-3500mm which is manufactured by using a pre-prepared raw material rod in zone-melting equipment through a zone-melting process, and the cross section of the silicon core is circular, which is also called a circular silicon core. The silicon core is obtained by cutting a straight-pulling silicon core rod through a diamond wire net, and the cut silicon core is square in cross section and is also called a square silicon core. Compared with a round silicon core, the square silicon core has the advantages of large productivity, consistent size specification, low rod pouring rate of the reduction furnace and the like. And raw material rods for cutting square silicon cores are mostly straight-pulling silicon core rods. The production of the Czochralski silicon core rod mostly adopts a process similar to that of the production of the monocrystalline silicon rod, and the silicon core round rod is in a polycrystalline state. After the ten thousand silicon core round bars are prepared, the processing flow mainly comprises the working procedures of cutting off, head and tail removing, cutting, cone grinding, punching, cleaning, drying and the like, hidden cracks are easy to generate in the processing process, the working procedures are numerous, and the manufacturing cost is high.

Directional solidification is a method for purifying and preparing solar-grade polysilicon by a metallurgical method, wherein an electromagnetic directional solidification technology is an important means with high efficiency, low energy consumption and low manufacturing cost. However, since silicon is a semiconductor and has poor conductivity, it cannot be directly induction-heated and melted, and it is necessary to preheat it, and it is considered that it is necessary to heat it at 700 ℃ or higher after the temperature is raised to a certain level. In addition, because electromagnetic semi-continuous directional solidification is adopted, if the molten pool is controlled improperly in the continuous casting process, the molten pool after preheating and melting start is still easy to appear, and the cold silicon material which is continuously added subsequently cannot be preheated well, so that the molten pool is extinguished, and the continuous directional solidification process is interrupted. There are also methods in which the silicon feedstock is placed on a graphite susceptor for induction heating, but this method introduces impurities such as carbon into the silicon feedstock.

To this end, embodiments of the present application provide a silicon core production apparatus 100 and a production method thereof, which can be used for directional solidification process production of silicon cores. The silicon core production equipment 100 and the production method thereof can directly generate silicon cores with different diameters, cutting loss is not needed, the generation cost is lower, and the generation efficiency is improved.

As shown in fig. 1, an embodiment of the present application provides a silicon core production apparatus 100, the silicon core production apparatus 100 including at least one furnace body 110, an induction heater 120, at least one crucible 130, a pre-heater 140, and a lifter 150. The furnace body 110 comprises a furnace wall 111, the furnace wall 111 encloses to form a furnace chamber 112, the induction heater 120 is installed in the furnace chamber 112, one side of the induction heater 120 is in sliding connection with the furnace wall 111, the crucible 130 is penetrated with the induction heater 120, the preheating heaters 140 are distributed on the periphery of the crucible 130, and the lifter 150 is connected with the end part of the crucible 130.

At least one of the index numbers is a natural number, and in this application, the number of the furnace bodies 110 may be one, two, three, four, etc. In this embodiment, the number of the furnace bodies 110 may be four, as shown in fig. 8. Each furnace body 110 comprises four surrounding furnace walls 111, two adjacent furnace bodies 110 can share one furnace wall 111, one side of the non-shared furnace wall 111 of each furnace body 110 is provided with a furnace door, and the furnace walls 111 are surrounded to form a furnace chamber 112 for generating silicon cores.

The induction heater 120 is an induction coil, can satisfy various heating processes by reasonably distributing an induction magnetic field, and has the advantages of selective local heating, high heating speed, high electric energy utilization rate and the like. The furnace wall 111 is provided with a chute, one side of the induction heater 120 can slide along the chute of the furnace wall 111 through a lifting structure, the part of the silicon core in a heating range is heated and melted through the arrangement of the induction heater 120, and meanwhile, in the continuous feeding process of silicon materials, the induction heater 120 can slide along the furnace wall 111 to adjust the heating part, so that the silicon materials separated from the heating range are condensed to form a round silicon rod.

In this application, the number of the crucibles 130 in one furnace body 110 may be one, two, three, four, five, etc., and may be specifically set according to actual production requirements. The inner diameter of the crucible 130 may be selected to meet the silicon core specifications to accommodate the formation of silicon cores of different diameters.

In this embodiment, the height of the crucible 130 may be set to 2000mm to 4000mm and the inner diameter may be set to 15mm to 45mm.

The pre-heater 140 may be a graphite heater, and the structure of the pre-heater 140 may be arc-shaped, the height of the pre-heater 140 may be 10% -30% of the height of the crucible 130, the pre-heater 140 is sleeved on the periphery of the crucible 130, and the crucible 130 in the heating range is preheated, so that the temperature reaches more than 700 ℃ at which the silicon material can be inductively heated.

The lifter 150 may be a hydraulic cylinder, a pneumatic cylinder, a linear motor, or the like having a lifting function. The telescopic end of the lifter 150 is connected with the bottom end of the crucible 130 to adjust the relative height of the crucible 130, so that the silicon material in the crucible 130 is in different heating states.

As shown in fig. 2, in some embodiments, the silicon core production apparatus 100 further includes a storage chamber 160, the storage chamber 160 being connected to an end of the furnace body 110 remote from the lifter 150.

The storage chamber 160 comprises a bin body 161, a cover body 162, an air extraction opening 163 and a feed inlet 164, wherein the bin body 161 can store polysilicon raw materials for preparing silicon cores, and the storage design weight of the polysilicon raw materials is 10% -20% of the required silicon core preparation weight. The bin body 161 is in a conical structure, and one end with a smaller inner diameter is connected with the furnace body 110, so that rapid material discharging is facilitated. The cover 162 covers and locates the storehouse body 161 and keeps away from one side of furnace body 110, and extraction opening 163 and feed inlet 164 all set up on the cover 162, and feed inlet 164 is used for the interpolation of polycrystalline silicon material, and extraction opening 163 is used for the evacuation processing before feeding to crucible 130.

As shown in connection with fig. 1 and 2, in some embodiments, a plurality of tapping pipes 170 are provided at a side of the storage chamber 160 connected to the furnace body 110, each tapping pipe 170 corresponds to one crucible 130, and the tapping pipes 170 are provided with a charging switch 180.

The number of the discharging pipes 170 in each furnace body 110 is the same as the number of the crucibles 130, so that each crucible 130 corresponds to one discharging pipe 170, and synchronous discharging of each crucible 130 is ensured. One end of the discharge pipe 170 is connected to the bin body 161 of the storage chamber 160, and the other end is aligned with the crucible 130 and feeds the corresponding crucible 130 under the control of the feed switch 180.

Further, the charging switch 180 includes a weighing sensor, so as to calculate the weight of the silicon material passing through the discharging pipe 170, and realize accurate control of charging in the process of generating the silicon core. The risk of interruption of the continuous directional solidification process due to too much cold silicon material to cause too fast drop of the temperature of the molten pool to be extinguished is avoided.

In some embodiments, the furnace body 110 is provided with an air inlet 113 at an end near the storage chamber 160, and an air outlet 114 is provided at a side of the furnace body 110 away from the storage chamber 160.

Through the arrangement of the exhaust port 114, before the multi-gold silicon material is filled for preheating, the furnace chamber 112 can be vacuumized, and after the vacuum degree reaches the requirement, high-purity inert gas is filled into the furnace chamber 112 at a certain flow rate, so that the heating efficiency is improved, and meanwhile, oxidation loss caused by contact of the material and air is avoided.

In this embodiment, argon may be used as the inert gas.

As shown in fig. 3, in some embodiments, the induction heater 120 includes a plurality of sub-induction heaters 121 and a bracket 122, and the plurality of sub-induction heaters 121 are each mounted to the bracket 122, and one side of the bracket 122 is connected to the furnace wall 111.

In each furnace body 110, the number of the sub-induction heaters 121 is the same as that of the crucibles 130, the support 122 may have a circular ring structure, and a connecting block is arranged on one side of the support, and is connected with the furnace wall 111 through the connecting block, so as to drive the support 122 to move up and down synchronously with the sub-induction heaters 121 fixed on the support 122. In order to improve the yield of the silicon core and the space utilization rate, a sub-induction heater 121 may be disposed at the center of the ring, and a plurality of other sub-induction heaters 121 are equidistantly distributed on the circumference of the central sub-induction heater 121.

In some embodiments, the furnace wall 111 is provided with a lifting mechanism that controls the lifting movement of the support 122 within the furnace chamber 112.

By way of example, the lifting mechanism may be a hydraulic cylinder, or a linear motor drive structure, etc. And the automatic lifting of the induction heater 120 is realized by a control system or a start switch.

In some embodiments, the side of the induction heater 120 adjacent to the pre-heater 140 is provided with a heat shield 123.

The heat shield 123 is secured to the underside of the support 122 to facilitate separation of the pre-heater 140 from the induction heater 120 and to reduce the effect of the heater's heat on the induction heater 120.

As shown in connection with fig. 6 and 7, in some embodiments, the crucible 130 includes a plurality of petals 131, adjacent petals 131 are spliced to each other, and cooling channels are provided in the petals 131.

In this embodiment, the crucible 130 may be a red copper crucible 130 and is divided into a plurality of segments 131 parallel to the axis of the crucible 130, and the number of segments 131 may be designed according to the size of the inner diameter of the crucible 130, for example, 3-30 segments. The induction heating operation is realized by means of the plurality of petals 131 being spliced into the crucible 130 so that the electromagnetic field of the induction heater 120 can penetrate through the wall of the crucible 130 and enter the interior of the crucible 130. Each of the petals 131 is provided with a cooling passage, and a water inlet passage and a water outlet passage, and circulating cooling water is introduced into the cooling passage to prevent the crucible 130 from being burned during the heating process.

In other embodiments, the number of petals 131 is preferably 6-15 petals.

In addition, the height and the inner diameter of the crucible 130 can be designed according to the height and the diameter of the silicon core commonly used at present, but since the silicon core is required to be cut off to be head and tail and the surface silicon powder shell is polished after the silicon core is produced, the height and the inner diameter of the crucible 130 are designed to be larger than the use height and the diameter of the silicon core.

As shown in connection with fig. 4 and 5, in some embodiments, the pre-heater 140 includes an external heater 141 and an internal heater 142, the external heater 141 being framed outside the internal heater 142, one crucible 130 being disposed within the internal heater 142, and a plurality of crucibles 130 being disposed between the external heater 141 and the internal heater 142.

The external heater 141 and the internal heater 142 may be annular graphite heaters, the internal diameter of the external heater 141 is larger than that of the external heater 142, and the centers of the two are coincident. The center of the furnace body 110 is provided with a crucible 130, and a plurality of crucibles 130 are equidistantly distributed on the periphery of the crucible 130 at the center, wherein the crucible 130 at the center is penetrated through the inner heater 142, and other crucibles 130 are penetrated between the outer heater 141 and the inner heater 142.

As shown in fig. 4, in one embodiment, the number of the crucibles 130 is five, and four crucibles 130 are further distributed on the circumference of the crucible 130 located at the center.

In one embodiment, as shown in fig. 5, the number of the crucibles 130 is nine, and eight crucibles 130 are distributed around the center crucible 130.

As shown in fig. 9, an embodiment of the present application further provides a silicon core production method, including:

s10, preparing in the early stage.

The crucible 130 is cleaned. All the crucibles 130 are cleaned, and the outer wall and the inner wall of the crucible 130 are cleaned, so that the silicon core is prevented from being polluted by impurities attached to the crucible 130.

And (5) smearing silicon mud. Mixing fine silicon powder with a proper amount of deionized water to form silicon paste, coating the silicon paste on the gap between two adjacent petals 131 of the crucible 130 and the inner wall surface of the crucible 130, and performing shade drying or baking treatment. By this step, the silicon melt is prevented from contacting the inner wall of the crucible 130 after the subsequent silicon material is heated and melted, thereby reducing secondary pollution of the inner wall of the crucible 130 to the silicon melt.

In some embodiments, the purity of the silicon powder may be 7-9N and the thickness of the slurry applied to crucible 130 may be 1mm-3mm.

And (5) detecting tightness. The crucible 130 is pressed for water test so as to detect whether water leakage exists in all the crucibles 130, and subsequent operation is performed after the water leakage does not exist in the crucibles 130, so that the silicon material is prevented from leaking after being heated and melted.

S20, preheating treatment.

As also shown in connection with fig. 1, the furnace chamber 112 is environmentally treated. The bottom of the crucible 130 is lowered to the heat generation area of the pre-heater 140, and the induction heater 120 is raised by a distance at least greater than the height of the heat generation area of the pre-heater 140. And adding polysilicon material with granularity meeting the requirement into the crucible 130, wherein the polysilicon material is positioned at the bottom of the crucible 130, and the filling height of the polysilicon material is 10-200mm greater than that of the heating area of the heater. Then, the furnace chamber 112 is subjected to a vacuum-pumping treatment, and after the degree of vacuum reaches the requirement, a high-purity inert gas such as argon is introduced into the vacuum furnace chamber 112 from the gas inlet 113 at a certain flow rate, and the gas outlet 114 is opened.

The storage chamber 160 is environmentally treated. Closing the charging switch 180, opening the cover 162 of the storage chamber 160, charging the polysilicon material with the particle size meeting the requirement into the storage chamber 160, and designing the size and charging weight of the storage chamber 160 according to the number of the crucibles 130 and the charging demand, wherein the charging weight is generally designed to be more than 10-20% of the demand weight. Then, the cover 162 of the storage chamber 160 is closed, and the vacuum is drawn from the suction port 163 to the storage chamber 160, so that the vacuum degree of the storage chamber 160 is identical to the vacuum degree of the main furnace chamber 112.

And (5) preheating treatment. The inner heater 142 and the outer heater 141 are started to heat the bottom of the crucible 130, and after the temperature of the polysilicon charge rises to the set temperature, the heating is stopped.

In the embodiment, the set heating temperature of the polysilicon material is 750-850 ℃ so as to meet the requirement that the conductivity of silicon is poor and the polysilicon material can be heated by induction only when the self temperature reaches more than 700 ℃.

S30, induction heating to generate the silicon core round bar.

As also shown in connection with fig. 2, the position of crucible 130 is adjusted. The crucible 130 is raised above the upper edge of the heater, i.e., the bottom of the crucible 130 is raised to a range that is free from the heating zone of the heater, while the induction heater 120 is lowered to the upper edge of the heater so that the preheated portion of the crucible 130 is within the induction heater 120. At this time, the tapping pipe 170 below the storage chamber 160 also exactly corresponds to the upper opening of the crucible 130 at the corresponding position.

And (5) induction heating and directional solidification. The induction heater 120 is activated to melt the silicon material in the crucible 130 by using the eddy current heating effect generated by induction. While heating, a cooling water system is turned on, and cooling water enters a cooling channel in the crucible 130 to cool the crucible 130. After the existing polysilicon charge in the crucible 130 is completely melted, the polysilicon charge is added to the crucible 130 at a certain rate. The feeding mode can adopt a point-action mode. And the weight of the silicon charge added per unit time should be less than the weight of the molten silicon charge per unit time of the induction heater 120 to reduce the risk of the continuous directional solidification process being interrupted due to the extinguishing of the melt pool caused by the reduced temperature after the addition of the cold silicon charge. In addition, while charging, the induction heater 120 is raised at a certain speed, and as the induction heater 120 is raised, the temperature of the silicon liquid in the crystallization area below the crucible 130 is gradually lowered, and the silicon liquid is positioned at the lower part of the crucible 130 and cooled, so that the silicon core solidifies from the bottom to the top of the crucible 130 at a certain speed until the growth of the silicon core is completed. And, during solidification of the silicon core, impurity elements having a partition coefficient of less than 1 in the silicon liquid are discharged upward from the solid/liquid interface.

And taking out the silicon rod and machining. After the silicon rod is cooled, the furnace chamber 112 is inflated to normal pressure, the furnace door is opened, and the silicon core round rod is taken out. The upper end section of the silicon rod enriched with impurities and the lower end section contacting the bottom of the crucible 130 are cut off, and the remaining silicon rod part is the purified silicon core round rod obtained through directional solidification. And then polishing, cone grinding and punching the surface of the purified silicon core round rod to finish the mechanical processing of the silicon core round rod.

And (5) cleaning and drying. And cleaning and drying the machined silicon core round rod to obtain the silicon core material required by industrial production.

In summary, compared with the method of producing a silicon core round rod by the Czochralski method and cutting into square silicon cores, the silicon core production equipment 100 and the production method thereof provided by the application can directly prepare the required round silicon cores with different diameters without cutting, and avoid the damage of the silicon cores in the cutting process and the silicon material loss in the cutting process. Compared with the production of the silicon core round rod by the Czochralski method, the preparation cost of the method is lower, and the energy consumption is lower. The equipment of this application can produce multiunit quantity silicon core simultaneously, and the productivity is bigger, and efficiency is higher.

The crucible 130 is primarily heated by the pre-heater 140, the base silicon material is heated by its heat, and when the temperature of the base silicon material is raised to a conductive state, cooling water is supplied to the crucible 130, and the induction heater 120 is turned on. After that, the silicon material is heated by induction until being melted, so that the problem that the silicon is not conductive at normal temperature and cannot be directly heated by an electromagnetic field is solved. And meanwhile, the direct contact heating of other materials such as carbon and the like and the silicon raw material is avoided, and impurities such as carbon and the like are introduced into the silicon raw material.

The drying in the shade or baking process is performed by applying the silicon paste to the gap between the adjacent two petals 131 of the crucible 130 and the inner wall surface of the crucible 130. Thereby preventing the silicon melt from contacting with the inner wall of the crucible 130 and reducing the secondary pollution of the crucible 130 wall to the silicon melt, and preparing the silicon core round rod with lower surface impurity content.

In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present application. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, the different embodiments or examples described in this specification and the features of the different embodiments or examples may be combined and combined by those skilled in the art without contradiction.

Although embodiments of the present application have been shown and described above, it will be understood that the above embodiments are illustrative and not to be construed as limiting the application, and that variations, modifications, alternatives, and variations may be made to the above embodiments by one of ordinary skill in the art within the scope of the application.

Claims (10)

1. A silicon core production apparatus, comprising:

at least one furnace body comprising furnace walls enclosing a furnace chamber:

the induction heater is arranged in the furnace chamber, and one side of the induction heater is in sliding connection with the furnace wall;

at least one crucible, wherein the induction heater is provided with a through hole, and the crucible penetrates through the through hole of the induction heater;

the pre-heaters are distributed on the periphery of the crucible;

and the lifters are arranged corresponding to the crucibles, and the end part of each crucible is connected with one lifter.

2. The silicon core production apparatus according to claim 1, further comprising a storage chamber connected to an end of the furnace body remote from the lifter.

3. The silicon core production apparatus according to claim 2, wherein a plurality of discharge pipes are provided on a side of the storage chamber connected to the furnace body, each of the discharge pipes corresponds to one of the crucibles, and the discharge pipes are provided with a charging switch.

4. The silicon core production equipment according to claim 2, wherein an air inlet is formed in one end of the furnace body, which is close to the storage chamber, and an air outlet is formed in one side of the furnace body, which is far away from the storage chamber.

5. The silicon core production apparatus according to claim 1, wherein the induction heater comprises a plurality of sub-induction heaters and a bracket, the plurality of sub-induction heaters are mounted on the bracket, and one side of the bracket is connected with the furnace wall.

6. The silicon core production apparatus according to claim 5, wherein the furnace wall is provided with a lifting mechanism that controls lifting movement of the support within the furnace chamber.

7. The silicon core production apparatus according to claim 5, wherein a side of the induction heater adjacent to the pre-heater is provided with a heat insulating plate.

8. The silicon core production apparatus according to claim 1, wherein the crucible comprises a plurality of petals, two adjacent petals are spliced with each other, and a cooling passage is provided in the petals.

9. The silicon core production apparatus according to any one of claims 1 to 8, wherein the pre-heater comprises an external heater and an internal heater, the external heater is framed outside the internal heater, one of the crucibles is provided in the internal heater, and a plurality of the crucibles are provided between the external heater and the internal heater.

10. A method of producing a silicon core, comprising:

the lifter drives the crucible to descend until the bottom of the crucible reaches a heating area of the preheater, polysilicon material is added into the crucible, the furnace chamber is vacuumized, and after the vacuum degree reaches a set value, high-purity inert gas is filled into the vacuum furnace chamber and an exhaust port is opened;

the preheating device heats the bottom of the crucible, and when the temperature of the polysilicon material rises to a set temperature, the heating is stopped;

the lifter drives the crucible to ascend until the bottom of the crucible is separated from the heating area range of the heater, and the induction heater is lowered to the corresponding area of the crucible for preheating treatment;

starting an induction heater for heating, adding the polycrystalline silicon material into the crucible after the existing polycrystalline silicon material in the crucible is completely melted, and lifting the induction heater synchronously during the feeding, wherein the polycrystalline silicon material below the induction heater is cooled and solidified until the growth of the silicon rod is completed;

and taking out the silicon rod, and carrying out mechanical processing, cleaning and drying on the silicon rod to obtain the silicon core.