KR101101989B1 - Manufacturing method of poly silicon and manufacturing device for the same - Google Patents

Abstract

The present invention is to produce a high-purity metal silicon with high efficiency, comprising the steps of preparing a first silicon in a molten state; Injecting the first silicon into a crucible to produce a second silicon having a flow falling from top to bottom; Allowing water to be injected into the inner space of the crucible; The flow of the second silicon flows through the space in which the water is being sprayed, and the sprayed water reaches both the surface and the core of the flow of the second silicon, whereby the flow of the second silicon is dispersed. To be a third silicon having; And discharging the third silicon from the crucible and solidifying the third silicon so as to become the fourth silicon.

Description

Manufacturing method of poly silicon and manufacturing device for the same

The present invention relates to a method for producing polysilicon and an apparatus for manufacturing the same, and more particularly, to a method for producing polysilicon and a production apparatus for producing a high quality polysilicon with high efficiency.

With the development of the electronics industry, polysilicon is very widely used.

Since silicon is usually present in the form of silicon oxide (SiOx) in a natural state, a high purity silicon metal is obtained through a reduction reaction. In particular, when the produced metal silicon contains impurities of a semiconductor process such as boron (B), it has a great influence on the properties of the polysilicon produced later.

On the other hand, when silicon carbide (SiC) is produced during the reduction reaction of silicon oxide, not only the production yield of silicon is reduced but also the furnace can be blocked by the silicon carbide. Therefore, it is very important to prevent the formation of silicon carbide in the final molten silicon in the reduction reaction of silicon oxide.

The present invention is to overcome the above problems and / or limitations, and an object of the present invention is to provide a method for producing polysilicon and a manufacturing apparatus thereof capable of producing high purity polysilicon with high efficiency.

Another object of the present invention is to provide a method for producing polysilicon and an apparatus for producing the polysilicon which can prevent boron, iron, aluminum, etc. from being produced in the produced polysilicon.

Still another object of the present invention is to provide a method for manufacturing polysilicon and an apparatus for manufacturing the same, which can prevent the formation of silicon carbide in molten silicon during the production of polysilicon.

In order to achieve the above object, the present invention comprises the steps of preparing a metal silicon; Melting the metal silicon in a vacuum to form molten silicon; Cooling the molten silicon to form polysilicon; Releasing the vacuum state; And scraping off the surface of the polysilicon.

According to another feature of the invention, the melting step is performed in a state of the first vacuum degree, injecting a gas containing argon gas into the molten silicon; And stirring the molten silicon.

According to another feature of the invention, after the stirring step may further comprise the step of maintaining the molten silicon at a second vacuum lower than the first vacuum degree.

The present invention also to achieve the above object, the first chamber; A second chamber coupled to the first chamber to form a space part; A first elevator for elevating the second chamber in a direction of the first chamber so that the first chamber and the second chamber are coupled or separated; A crucible accommodated in the space part and linked to driving of the second chamber; A heater for heating the crucible; A cooler for cooling the crucible; And a vacuum pump for vacuuming the space part when the first chamber and the second chamber are coupled to each other.

According to another aspect of the present invention, further includes a stirrer accommodated in the space portion, the stirrer, a blade for stirring the molten silicon in the crucible and having a plurality of injection holes; A gas injector for injecting gas into the molten silicon through an injection hole of the blade; And a second elevator for elevating the blade in the direction of the crucible.

According to the present invention as described above it is possible to obtain a high-purity polysilicon with a minimum content of impurities.

In addition, by suppressing the production of silicon carbide in the molten silicon, it is possible to improve polysilicon production efficiency and to increase the polysilicon purity.

Hereinafter, the present invention will be described in detail with reference to embodiments of the present invention shown in the accompanying drawings. But. The present invention may be modified in various other forms, and the scope of the present invention is not limited to the embodiments described below. The embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art. Accordingly, the shape and size of elements in the drawings may be exaggerated for clarity, and the elements denoted by the same reference numerals in the drawings are the same elements.

1 is a flowchart sequentially illustrating a method of manufacturing polysilicon according to an embodiment of the present invention. 2 to 9 are schematic diagrams illustrating an apparatus for manufacturing polysilicon performing the manufacturing method of FIG. 1.

First, the first silicon 21 in a molten state is manufactured in the furnace 11 (S1).

The furnace 11 may be an electric furnace, but is not necessarily limited thereto.

First, the furnace 11 is filled with a first component group consisting of silicon oxide, charcoal, petroleum coke and coal and a second component group consisting of wood or corn core.

Charcoal, petroleum coke and coal in the first component group and the second component group serve as a source of carbon as a reducing agent.

Silicon oxide preferably contains 46 to 64% by weight. Charcoal and coal each contain 6-7 wt% and petroleum coke 20-20 wt%. And the second component group is to be included 4 to 15% by weight.

According to a preferred embodiment of the present invention, 56.8% by weight of silicon oxide, 6.8% by weight of charcoal, 22.7% by weight of petroleum coke, 6.8% by weight of coal, and 6.8% by weight of wood chips as the second component group. In this case, it was possible to prevent the formation of silicon carbide in the molten first silicon 21. In addition, the purity of the resulting polysilicon was the best.

According to another embodiment of the present invention, corn cores may be used instead of the wood chips. When using corn cores, it is desirable to add approximately twice the amount of wood chips.

The composition ratio as described above may be adjusted to an appropriate ratio depending on the process conditions.

On the other hand, the silicon oxide, coal, petroleum coke, wood chips, corn core and the like is preferably added to the furnace by adjusting the size and ratio.

In the case of silicon oxide, it is preferable to add a size of 8 to 80mm, at this time, it may be included in the powder less than 20mm, but preferably not more than 20% of the total amount of silicon oxide.

Table 1 below shows the state of the polysilicon produced by the input size of the silicon oxide. As can be seen in Table 1, the input size of the silicon oxide preferably satisfies the above conditions.

Silicon oxide
Input size 1-7mm 8-80mm 8-80mm 8-80mm 81-150mm 151-250mm Input condition Less than 3mm
Less than 20% Less than 20mm
Less than 5% Less than 20mm
Less than 10% Less than 20mm
Less than 20% Less than 20mm
Less than 40% Less than 20mm
Less than 50% Experiment result Bad Good Good The best Bad Bad

Coal preferably has a size of 6 to 10 mm. Some of the fine powder of less than 1mm may be included, but it is preferable not to exceed 20% of the total coal content.

Table 2 shows the state of the polysilicon generated by the input size of the coal. As can be seen from Table 2, the input size of coal preferably satisfies the above conditions.

Coal
Input size 1-5mm 6-10mm 6-10mm 11-15mm 11-15mm 11-15mm 16-20mm 21-25mm Input condition Less than 1mm
Less than 20% Less than 1mm
Less than 10% Less than 1mm
Less than 20% Less than 1mm
Less than 30% Less than 1mm
Less than 40% Less than 1mm
Less than 50% Less than 1mm
Less than 20% Less than 1mm
Less than 20% Experiment result Bad Good The best Bad Bad Bad Bad Bad

The petroleum coke is preferably loaded with a particle size of 30 mm or less. At this time, it is preferable not to exceed 20% of the total petroleum coke amount in the case of fine powder having a diameter of less than 3mm.

Table 3 below shows the state of the polysilicon produced by the input size of the coke. As can be seen from Table 3, the coke input size preferably satisfies the above conditions.

cokes
Input size 0-30mm 0-30mm 0-30mm 60-90mm 90-120mm Input condition Less than 3mm
Less than 40% Less than 3mm
Less than 20% Less than 33mm
Less than 20% Less than 63mm
Less than 20% 93mm or less
Less than 20% Experiment result Bad Good Bad Bad Bad

It is preferable to use wood chips having a size of 10 to 150 mm. It is desirable that the amount smaller than 30 mm does not exceed 20% of the total amount of wood chips.

Table 4 shows the state of the polysilicon produced by the input size of the wood chips. As can be seen in Table 4, the input size of the wood chips preferably satisfy the above conditions.

Wood carving
Input size 1-10mm 10-150mm 10-150mm 150-300mm 300-500mm Input condition Less than 2mm
Less than 20% Less than 3mm
Less than 30% Less than 30mm
Less than 20% Less than 170mm
Less than 20% Less than 320mm
Less than 20% Experiment result Bad Good The best Bad Bad

Corn cores are preferably used having a size of 200 to 250mm. Some of the less than 100mm may be included, but it is preferable not to exceed 20% of the total corn core content.

Table 5 shows the state of the polysilicon produced by the input size of the corn core. As can be seen in Table 5, the input size of the corn core preferably satisfies the above conditions.

cokes
Input size 0-100mm 100-200mm 200-250mm 200-250mm 200-250mm Input condition Less than 100mm
Less than 40% Less than 100mm
Less than 20% Less than 100mm
Less than 20% Less than 50mm
Less than 20% Less than 100mm
Less than 40% Experiment result Bad Good The best Bad Bad

By adjusting the content as described above it was possible to suppress the production of silicon carbide in the molten first silicon 21 to the maximum and the purity of the produced polysilicon could be improved.

These components are loaded into the furnace 11 and then melted at 2000 ° C. or higher to obtain the first silicon 21 in a molten state. At this time, a small amount of oxygen can be blown into the furnace 11.

This first silicon 21 is poured into the first crucible 12 as shown in FIG. 2, and then the first crucible 12 of the first crucible 12 can be seen in FIG. 3. Inject).

The first crucible 12 may be a movable crucible for injecting the molten first silicon 21 into the second crucible 13 by a predetermined amount, although not shown in the drawing, the first crucible 12 may be used. A separate heater facility may be further installed to maintain the temperature of the first silicon 21. Of course, the first silicon 21 may be directly injected from the furnace 11 into the second crucible 13 without using the first crucible 12 separately.

Next, the first silicon 21 is injected into the second crucible 13 from the first crucible 12. At this time, the first silicon 21 discharged from the first crucible 12 becomes a second silicon 22 having a flow falling from the top to the bottom (S2).

The flow of the second silicon 22 flows into the internal space 14 of the second crucible 13 as it is, and water is injected into the space 14 by a plurality of injection nozzles 15. .

That is, as shown in Figure 4, the second crucible 13 is equipped with a plurality of injection nozzles 15 from the top to the bottom along the inner wall. The injection nozzle 15 injects high pressure water into the inner space 14 of the second crucible 13 before the flow of the second silicon 22 flows into the second crucible 13 (S3).

The flow of the second silicon 22 flows into the space 14 of the second crucible 13 into which the high pressure water is injected. At this time, the flow rate of the second silicon 22 flowing into the space 14 of the second crucible 13 is adjusted so that the water sprayed from the injection nozzle 15 flows on the surface of the second silicon 22 flow and It is desirable to reach all over the core. Accordingly, the flow of the second silicon 22 is to be the third silicon 23 having the dispersed flow (S4). In other words, the flow of the second silicon 22 becomes the third silicon 23 having the spray-type flow by the pressure of the water injected from the injection nozzle 15.

As the flow of the second silicon 22 passes through the space where the high pressure water is injected, boron B in the second silicon 22 is removed. Therefore, the amount of boron is reduced as much as possible in the generated third silicon 23 to further increase the purity of the metal silicon formed later.

Meanwhile, at the same time as the high pressure water is sprayed, some spray nozzles 15 may spray oxygen and / or argon gas, and in addition, the air may be mixed and sprayed. In this case, impurities such as iron and aluminum can be removed.

The second crucible 12 is provided with a discharge hole 16, so that the formed third silicon 23 can be discharged as it is (S5).

The discharged third silicon 23 solidifies gradually while flowing along the moving table 17 to become the fourth silicon 24 (S6). Cooling water may be sprayed on the movable table 17 to promote solidification of the fourth silicon 24.

The fourth silicon 24 produced is metallic silicon. The fourth silicon 24 is crushed using the crusher 26 (S7). The crushed fourth silicon powder is transferred to the polysilicon maker 30. The generated fourth silicon 24 may be transferred to the polysilicon maker 30 in the form of agglomerates, but it is more preferable to be crushed and put into the polysilicon maker 30 in the powder state, and when the powder is used, polysilicon Purity is further improved.

5 to 9 show the polysilicon maker 30 in detail.

The polysilicon maker 30 includes a first chamber 31 and a second chamber 32. The second chamber 32 is connected to the first elevator 39 so as to move relative to the fixed first chamber 31. Of course, the second chamber 32 may be fixed and the first chamber 31 may be elevated.

When the first chamber 31 and the second chamber 32 are coupled to each other, the first chamber 31 and the second chamber 32 may have a space 50 therein and may be sealed to allow the space 50 to be in a vacuum state.

A vacuum vent 37 is installed in the second chamber 32 to be connected to the vacuum pump 38 to adjust the degree of vacuum of the space 50.

The third crucible 33 is disposed in the space 50. The third crucible 33 is connected to the first elevator 39 to move up and down in conjunction with the lifting motion of the second chamber 32.

A coil-shaped heater 34 is disposed around the side wall of the third crucible 33, and a cooler 35 and a temperature holder 36 are provided on the lower surface of the third crucible 33.

The space unit 50 may be further provided with a stirrer 40, preferably may be installed in the second chamber (32).

The stirrer 40 has a blade 41 for stirring molten silicon in the third crucible 33, and the blade 41 is moved up and down in the direction of the third crucible 33 to move the blade 41. And a second elevator 43 for rotating.

As shown in FIG. 9, the blade 41 has a plurality of injection holes 42 formed along the blade 41, and the injection holes 42 are connected to the gas injector 44. The gas may be injected into the third crucible 33 through the hole 42.

First, as shown in FIG. 5, the polysilicon maker 30 is in a state in which the first chamber 31 and the second chamber 32 are separated from each other. And the heater 34 is operated so that the 3rd crucible 33 may be 1500 degreeC or more.

The crushed fourth silicon 24 is introduced into the third crucible 33, and the first elevator 39 is operated to allow the second chamber 32 to be coupled to the first chamber 31. Let 50 be in a sealed state.

In this state, the vacuum pump 38 is operated so that the space 50 is in a vacuum state with the first vacuum degree. The first vacuum degree is preferably such that the vacuum pressure of 100Pa to 10Pa.

In the state of the first vacuum degree, the alternating power of 50 kw or more is applied to the heater 34 to completely melt the fourth silicon 24 in the third crucible 33 (S8) to produce a fifth silicon in a molten state.

The fourth silicon 24 usually starts to melt at 1400 ° C. and then melts when it reaches 1500 ° C.

When the temperature of the fifth silicon in the molten state reaches 1800 ° C., as shown in FIG. 7, the blade 41 of the stirrer 40 is lowered in the direction of the third crucible 33 and through the gas injector 44. The gas is injected into the fifth silicon from the injection hole 42 of the blade 41 (S9). The gas is preferably provided with a mixed gas of 98% argon gas and 2% oxygen gas.

While spraying the gas as described above, the blade 41 is introduced into the fifth silicon accommodated in the third crucible 33 to stir the fifth silicon (S10). The injection and agitation of the gas can be done simultaneously.

The rotational speed of the blade 41 is preferably 30-50 rpm, and the injection amount of the gas is preferably 1-5 L / min. Gas injection time shall be 30 minutes-1 hour.

Next, the vacuum pump 38 is operated so that the space 50 becomes the vacuum pressure of the second vacuum degree. The second degree of vacuum has a higher vacuum degree than the first degree of vacuum, that is, a lower pressure vacuum pressure, so that the vacuum pressure is 10 ⁻¹ Pa or less (S11). According to a preferred embodiment of the present invention, the vacuum pressure is 9.6 * 10 ⁻² Pa and then vacuumed for 1 hour.

Thereafter, the heater 34 is turned off, and as shown in FIG. 8, the second chamber 32 is slowly lowered to release the sealing with the first chamber 31 (S12). It is preferable that the descending speed of the 2nd chamber 32 shall be 4-5 cm / h. At this time, the cooler 35 is operated to cool the third crucible 33.

When the vacuum is released at the same time as the cooling is performed, the fifth silicon crystallizes to advance polysilicon, and at the same time, the surface shrinks to form a sixth silicon having a broken shape (S13).

The broken surface of the sixth silicon in which the surface is shrunk is cut to obtain a seventh silicon that is internally high-purity polysilicon (S14). The broken surface of the sixth silicon is in a state where there are many impurities, and the upper part has more impurities than the side parts. Thus the top cuts at least 1/10 the thickness and the side cuts at least 1/20 thickness.

The seventh silicon thus produced becomes high purity polysilicon having a purity of 99.9999%.

Although not illustrated in the drawings, the seventh silicon may further remove impurities such as boron (B) by applying plasma in a vacuum again.

In addition, the steps S7 to S14 may be repeated a plurality of times to obtain high purity polysilicon desired by the consumer.

The present invention is not limited by the above-described embodiment and the accompanying drawings, but is intended to be limited by the appended claims, and various forms of substitution, modification, and within the scope not departing from the technical spirit of the present invention described in the claims. It will be apparent to those skilled in the art that changes are possible.

1 is a flowchart sequentially illustrating a method of manufacturing polysilicon according to an embodiment of the present invention.

2 is a schematic view showing a furnace and a first crucible which are part of the apparatus for producing polysilicon according to the embodiment of the present invention.

3 is a schematic view showing a first crucible, a second crucible, and a moving table that are part of a polysilicon manufacturing apparatus according to an embodiment of the present invention.

4 is a schematic view for explaining the second crucible of FIG. 3 in more detail.

5 is a schematic diagram showing a polysilicon manufacturing machine which is part of a polysilicon manufacturing apparatus according to an embodiment of the present invention.

FIG. 6 is a schematic diagram illustrating a state in which a first chamber and a second chamber are coupled to the polysilicon maker of FIG. 5.

FIG. 7 is a schematic diagram illustrating a state in which a stirrer is operated in the polysilicon maker of FIG. 6.

FIG. 8 is a schematic diagram illustrating a state in which a coupling between the first chamber and the second chamber is released in the polysilicon maker of FIG. 7.

FIG. 9 is a partially enlarged view illustrating an example of a blade in the polysilicon maker of FIG. 5.

Claims (5)

delete delete delete A first chamber; A second chamber coupled to the first chamber to form a space part; A first elevator for elevating the second chamber in a direction of the first chamber so that the first chamber and the second chamber are coupled or separated; A crucible accommodated in the space part and linked to driving of the second chamber; A heater for heating the crucible; A cooler for cooling the crucible; And And a vacuum pump for vacuuming the space part when the first chamber and the second chamber are coupled to each other. 5. The method of claim 4, Further comprising a stirrer accommodated in the space portion, the stirrer, A blade for stirring molten silicon in the crucible and having a plurality of injection holes; A gas injector for injecting gas into the molten silicon through an injection hole of the blade; And And a second elevator for elevating the blade in the direction of the crucible.

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