KR101640286B1 - Apparatus and method for producing polysilicon using streamer discharge - Google Patents

Abstract

According to the present invention, there are provided a horizontal tube having an inner space through which a reaction gas and a reducing gas can flow; A sawtooth wire extending into the interior of the horizontal tube; An electrode formed on an outer surface of the horizontal tube; A power source for applying an alternating current to the sawtooth wire and the electrode; And an inclined tube disposed downstream of the horizontal tube and capable of raising an internal temperature to a predetermined temperature, wherein a streamer plasma discharge generated between the sawtooth wire and the electrode Wherein the reaction gas and the reducing gas can be dissociated. A method of manufacturing polysilicon using the above-described polysilicon manufacturing apparatus is also provided.

Description

[0001] Apparatus and method for producing polysilicon using streamer discharge [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an apparatus and a method for manufacturing polysilicon, and more particularly, to an apparatus and a method for manufacturing polysilicon capable of obtaining high-purity polysilicon by dissociating a gas mixture by a streamer plasma discharge .

Polysilicon is a raw material for semiconductor devices, solar cell devices, and the like. Conventionally, various methods for producing silicon used as a raw material for a semiconductor or a solar cell have been known, and some of them have already been carried out industrially.

Most of the currently used high purity polysilicon is produced by a chemical vapor deposition method. Can be prepared by reacting a trichlorosilane gas with a reducing gas such as hydrogen gas, specifically as shown in Reaction Scheme 1 below.

[Reaction Scheme 1]

SiHCl ₃ (gas) + H ₂ (gas) → Si (solid) + 3HCl (gas)

An example of a commercialized process for producing polysilicon is the Siemens method. In the Siemens process, a silane-based gas as a reaction gas and hydrogen gas as a reducing gas are fed together into a vertical reactor, and when heat of a temperature higher than the deposition temperature of silicon is transferred to the reaction gas and the reducing gas by heating the silicon rod installed in the vertical reactor, The polysilicon is precipitated.

However, such a conventional Siemens reactor usually consumes a large amount of electric energy of about 65 to 200 KWh / kg, and the cost for such electric energy accounts for a very large portion of the cost of manufacturing the polysilicon. Further, since the precipitation is of a batch type, there is a problem that an extremely complicated process such as installation of a silicon rod, conduction heating, precipitation, cooling, extraction, and vertical reactor cleaning must be carried out.

Another method is the precipitation by a fluidized bed. This method is a method of continuously producing silicon grains of 1 to 2 mm by depositing silicon on fine silicon particles by supplying silane streams while supplying fine grains of about 100 microns into the precipitation nuclei by using a fluidized bed. This method has an advantage of being able to operate for a relatively long period of time. However, since monosilane having a low precipitation temperature is used as a raw material for silicon, generation of fine silicon by thermal decomposition of monosilane and precipitation of silicon into the reactor wall are likely to occur even at a relatively low temperature Periodic cleaning or replacement of the reaction vessel is necessary.

On the other hand, Korean Patent No. 10-0692444 discloses an apparatus for producing polycrystalline silicon using a vertical reduction reactor. (A) a tubular container having an opening serving as a silicon outlet at a lower end thereof; (b) a tubular container having an opening at an arbitrary height from the lower end of the tubular container (C) a space surrounded by an inner wall heated to a temperature not lower than the melting point of silicon, the inner wall having an inner diameter smaller than the inner diameter of the cylindrical container, (D) a first sealing gas supply pipe for supplying a sealing gas to the gap formed by the inner wall of the tubular container and the outer wall of the chlorosilane supply pipe, and, optionally, (e) a hydrogen supply pipe for supplying hydrogen gas into the tubular container.

Fig. 1 schematically shows an apparatus for producing polysilicon belonging to the type of vertical reduction reactor.

Referring to the drawings, an apparatus for producing polysilicon includes a reaction gas inlet 11 in an upper portion 10a of a reactor 10, a vacuum conduit 12 on one side of a middle portion 10b of the reactor 10, And a discharge conduit 13 are provided. In the lower portion 10c of the reactor 10, the collection, cooling and casting of molten silicon are formed.

A reactive gas such as monosilane, dichlorosilane, TCS, or STC is supplied through the reaction gas inlet 11. A vacuum conduit 12 may be used to form a vacuum atmosphere for cleaning and purging the interior space after operation of the reactor 10 and a discharge conduit 13 may be used to discharge the waste gases generated during the reaction An upper portion 10a of the reactor 10 is provided with a heating coil 14. An RF current is applied to the induction heating coil 14 so that an eddy current is generated in the reaction tube 21 to generate heat, Heat is applied to the gas flowing into the gas inlet through the heated wall of the reaction tube 21 to induce the precipitation reaction.

Figure 2 is a schematic cross-sectional view of the upper portion 10a of the reactor shown in Figure 1.

Referring to FIG. 1, a reaction tube 21 is provided in an upper portion 10a of the reactor, and a reaction gas such as a silane-based gas is supplied to the reaction tube 21 through a reaction gas supply tube 11. On the outer side of the reaction tube (21), a heating coil (23) is arranged on the surface of the insulating pipe (22). A sealing gas 25 is supplied through a sealing gas supply pipe not shown in the drawing to be filled between the reaction tube 21 and the insulating tube 22 and between the insulating tube 22 and the outer tube 26. The sealing gas 25 is supplied in order to prevent the reaction gas from leaking through the gap between the reaction tube 21 and the insulation 22 and between the insulation 22 and the outer insulation 26. [ Also, a reducing gas such as hydrogen is supplied through a reducing gas supply pipe (not shown) or a mixed gas of a reducing gas and a silane gas.

2, the heating coil 21 is not wound on the upper region of the reaction tube 21 indicated by A while the heating coil 21 is wound on the lower region of the reaction tube 21 indicated by B. This structure is for the thermal stability of the feed pipe and for the overall isothermal distribution, and the B region requires a length of 3 to 4 times the diameter of the reaction tube.

Therefore, the heat transmitted to the reaction tube 21 by the heating coil 21 is concentrated in the lower region indicated by B, rather than the upper region indicated by A. In the apparatus for producing polysilicon described with reference to FIGS. 1 and 2, the reaction gas and the reducing gas introduced into the reaction tube 21 are in contact with the wall surface, It has a lot of problems.

 That is, since the heat transfer is not smooth for the gas flowing through the center of the reaction tube 21 which is the farthest distance from the heating coil 23, the reduction reaction is slow and therefore the overall production efficiency is lowered and the energy efficiency .

SUMMARY OF THE INVENTION It is an object of the present invention to provide an apparatus and a method for manufacturing improved polysilicon capable of solving the problems of the prior art as described above.

Another object of the present invention is to provide an apparatus and a method for manufacturing polysilicon that can improve the production efficiency.

It is another object of the present invention to provide an apparatus and a method for manufacturing polysilicon in which gas dissociation is performed using a streamer plasma discharge.

In order to achieve the above object, according to the present invention,

A horizontal tube having an inner space through which a reaction gas and a reducing gas can flow; And

And a streamer plasma discharging means for dissociating the reaction gas and the reducing gas.

According to one aspect of the present invention,

A horizontal tube having an inner space through which a reaction gas and a reducing gas can flow;

A sawtooth wire extending into the interior of the horizontal tube;

An electrode formed on an outer surface of the horizontal tube;

A power source for applying an alternating current to the sawtooth wire and the electrode; And

And an inclined pipe disposed downstream of the horizontal pipe and capable of raising the internal temperature to a predetermined temperature,

The reaction gas and the reducing gas may be dissociated by a streamer plasma discharge generated between the sawtooth wire and the electrode.

According to one aspect of the present invention, the sawtooth wire includes a wire portion extending in the longitudinal direction and a toothed portion having a plurality of teeth projected radially at predetermined intervals along the wire portion. The serrations can be made of a conductive material.

According to another aspect of the present invention, the horizontal tube includes a mixing region in which the reaction gas and the reducing gas are mixed, and a dissociation region in which the mixed reaction gas and reducing gas are dissociated, And a precipitation region in which the reacted gas and the reducing gas react to precipitate the polysilicon.

According to another aspect of the present invention, the slant pipe is provided with a heating electric coil provided on the outer surface of the slant pipe.

According to another aspect of the present invention, there is further provided a take-out pipe on the downstream side of the inclined pipe, and the polysilicon deposited in the inclined pipe can be cast in the take-out pipe.

In the present invention, the horizontal pipe, the slant pipe, and the sawtooth wire may independently be made of at least one of molybdenum (Mo) and tantalum (Ta).

Also, in the present invention, the reaction gas may include any one of monosilane, dichlorosilane, trichlorosilane (TCS), and tetrachlorosilane (STC), and the reducing gas may include hydrogen.

Further, according to the present invention,

Introducing a reaction gas and a reducing gas into a horizontal tube;

Mixing the reaction gas and the reducing gas in the horizontal tube;

Dissipating the mixed reaction gas and the reducing gas by causing a streamer plasma discharge inside; And

And causing the dissociated reaction gas and the reducing gas to react with each other by heating to a predetermined temperature or higher, thereby precipitating and melting the polysilicon.

According to an aspect of the present invention, the streamer plasma discharge may be caused by applying an alternating current between a sawtooth wire installed inside the horizontal tube and an electrode provided outside the horizontal tube. When an electric current is applied, due to the structural characteristic of the sawtooth wire, an equipotential surface is formed in the entire space of the horizontal tube, and a stable plasma discharge space can be generated.

The apparatus and the method for producing a polysilicon according to the present invention perform the precipitation process after sufficiently dissociating the reaction gas and the reducing gas under a mild condition of similar atmospheric pressure and at a lower temperature than the conventional thermal plasma process, The production efficiency and the energy efficiency of the polysilicon can be improved. In particular, since the reaction gas and the reducing gas are dissociated using the streamer plasma discharge, the activity and the reactivity of the chemical species increase at a low voltage, leading to an increase in the yield. The streamer discharge can save about 30% of electric energy compared to the conventional high temperature precipitation process by the low temperature plasma method.

1 is a schematic perspective view of an apparatus for producing polysilicon according to the prior art.
2 is a schematic cross-sectional view of the upper portion of the reactor shown in Fig.
3 is a schematic configuration diagram of a polysilicon device according to an embodiment of the present invention.
4 is a schematic perspective view of a sawtooth wire included in the polysilicon device shown in FIG.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to the embodiments of the present invention shown in the accompanying drawings. It is to be understood, however, that the invention is not to be limited to the specific embodiments, but includes all modifications, equivalents, or alternatives falling within the spirit and scope of the present invention.

In the drawings, like reference numerals are used for similar elements.

The terms first, second, A, B, etc. may be used to describe various components, but the components are not limited by these terms, and may be used to distinguish one component from another Only.

The term " and / or " includes any one or a combination of the plurality of listed items.

It is to be understood that when an element is referred to as being "connected" or "connected" to another element, it is to be understood that other elements may be directly connected or connected, or intervening elements may be present.

The singular expressions include plural expressions unless otherwise specified.

It will be understood that the terms "comprises", "having", and the like have the same meanings as the features, numbers, steps, operations, elements, parts or combinations thereof described in the specification, Does not exclude the possibility that an operation, component, component, or combination thereof may be present or added.

The present invention relates to a horizontal tube having an inner space through which a reaction gas and a reducing gas can flow; And a streamer plasma discharge means for dissociating the reaction gas and the reducing gas. The present invention also provides a polysilicon manufacturing apparatus and a polysilicon manufacturing method using the same.

FIG. 3 shows a schematic configuration diagram of a polysilicon manufacturing apparatus according to an embodiment of the present invention.

Referring to the drawings, an apparatus for producing polysilicon according to an embodiment of the present invention includes a horizontal tube 32 that is dissociated while flowing in a mixed state of a reaction gas and a reducing gas, An inclined pipe 33 for producing polysilicon by heating to a predetermined temperature or higher and a take-out pipe 39 disposed on the downstream side of the inclined pipe 33. A sawtooth wire 37 is extended in the horizontal pipe 32 and the inside of the slant pipe 33 is raised to a predetermined temperature or higher in the slant pipe 33, A heating device (not shown) is provided.

A reaction gas inlet port 35 and a reducing gas inlet port 36 are provided at one end of the horizontal pipe 32. A reaction gas such as a silane gas is introduced into the horizontal pipe 32 through the reaction gas inlet 35, And the silane-based gas includes, for example, any one of monosilane, dichlorosilane, trichlorosilane (TCS), and tetrachlorosilane. And the reducing gas is introduced into the horizontal tube 32 through the reducing gas inlet 36. The reducing gas typically comprises hydrogen, and in another example, it contains Zn or Na.

The horizontal tube 32 may be composed of various materials, for example, a conductor or a dielectric material.

In the case where the horizontal tube 32 is composed of a dielectric, an electrode (not shown) is provided on the outer surface of the horizontal tube 32. The horizontal tube 32 may be formed of, for example, a quartz material, and an electrode of a metal material may be formed on the outer surface of the horizontal tube 32. The electrode provided in the horizontal tube 32 is connected to the AC power source 34 through a cable 34b. Therefore, when a current is applied from the AC power source 34, a streamer plasma reaction may occur between the sawtooth wire 37 and the electrode (not shown) on the horizontal tube 32.

In the case where the horizontal tube 32 is formed of a conductor, electric charge is applied to the entire horizontal tube 32 through the electrode terminal so that a uniform plasma discharge space formed by the equipotential surface between the serrated wire 37 and the horizontal tube 32 . In the case of a dielectric body, an equal area electrode must be provided on the outer surface of the horizontal tube 32 so that the same effect as the conductor can be expected.

 The sawtooth wire 37 is installed so as to extend horizontally inside the horizontal tube 32. One end of the serrated wire 37 is connected to the AC power supply 34 through a cable 34a. The end of the serration wire 37 which is not connected to the power source 34 is connected to the electrode provided in the horizontal pipe 32 or the outside of the horizontal pipe to form a closed circuit. This is because, when the horizontal tube 32 is made of a conductor, the horizontal tube 32 itself can be an electrode.

That is, according to the present invention, a streamer plasma can be generated at atmospheric pressure using an AC power source to efficiently perform a polysilicon deposition reaction. The streamer discharge is a discharge of the same principle as that of lightning occurs in the natural world, and the electron kinetic energy inside the discharge space is very large. Therefore, when the raw material gas is injected into this space, the effect of increasing the dissociation rate of the gas by about 40 to 60% can be obtained. The high dissociation rate increases the activity and reactivity of the species and eventually increases the yield.

As the discharge gas of the streamer discharge, argon or hydrogen can be used as in the conventional low-temperature plasma. In particular, if hydrogen is used as the discharge gas, it is the same gas source as the reducing gas, which can help to reduce maintenance cost and production cost.

Fig. 4 shows a schematic perspective view of a sawtooth wire. Referring to the drawing, a sawtooth wire 72 is formed by arranging a plurality of serrated portions 37a at predetermined intervals on a wire portion 37b extending in the longitudinal direction. The toothed portion 37a may be formed of a conductor having teeth 37c formed along the circumference as shown in the figure.

The electric power applied along the wire portion 37b is conducted by the toothed portion 37a and the streamer plasma discharge is generated between the tip portion of the tooth 37c and the electrode on the outer surface of the horizontal tube 32 shown in Fig. Lt; / RTI > As shown in the drawing, the teeth 37c are formed along the circumference of the toothed portion 37a, and an electrode (not shown) is formed along the circumference on the outer surface of the horizontal tube 32 corresponding thereto .

For example, the horizontal tube 32 may be formed of a conductive material so that the horizontal tube itself serves as an electrode, and the entire outer surface of the tube may be covered with a conductive material to serve as an electrode. In another example, an annular electrode (not shown) may be provided on the outer surface of the horizontal tube 32. A streamer flame discharge occurs between the tooth 37c of the tooth portion 37a and the electrode of the horizontal tube 32 or the outer surface when electric power is applied from the AC power source 34, Lt; RTI ID = 0.0 > radially < / RTI >

A vacuum exhaust port 38 is formed at one side of the horizontal pipe 32 and a vacuum pump (not shown) may be used to vacuum the horizontal pipe 32 through the vacuum exhaust port 38.

Referring again to FIG. 3, the horizontal tube 32 includes a mixing region 41 close to the reaction gas inlet 35 and the reducing gas inlet 36, and a dissociation region 41 corresponding to the extended portion of the serrated wire 37. [ (42). In the mixed region 41, the reactive gas and the reducing gas are actively mixed, while in the dissociated region 42, the dissociation of the reactive gas may be actively generated by the streamer plasma discharge.

The inclined pipe (33) is disposed on the downstream side of the horizontal pipe (32). The mixture of the reaction gas and the reducing gas is passed through the dissociation region 42 of the horizontal tube 32 and then dissociated and then introduced into the inclined tube 33. As described above, the slanting pipe 33 is provided with a heating device for raising the internal temperature of the slanting pipe 33 to a predetermined temperature or higher. The heating device surrounds the outer surface of the slanting pipe 33 (Not shown) for heating the heating coil. By the heating device, the inclined tube 33 can maintain a temperature of 1430 degrees Celsius or more, which is a temperature at which high-purity silicon can be precipitated by the reaction of the dissociated mixed gas. The precipitated silicon may be in a solid state, or it may be in a state of a liquid to melt depending on the temperature of the slanting tube 33. That is, if the temperature of the inclined pipe 33 is maintained at a remarkably higher value than 1430 ° C, which is the deposition temperature of silicon, the silicon remains in a molten state with precipitation. Thus, the precipitated liquid silicon can flow with gravity toward the take-out tube 39 along the inclined tube 33. In another example, the silicon can be precipitated in a solid state, and the precipitated solid silicon can be transferred to the downstream side by a conveying means (not shown) provided in the inclined tube 33. The conveying means includes, for example, a conveyor belt on which deposited silicon may be deposited, a transportable tray, and the like. The inclined pipe 33 constitutes a precipitation region 43 in which silicon is precipitated.

The take-out pipe 39 is disposed on the downstream side of the inclined pipe 33, and high-purity silicon in a solid state or a liquid state can be obtained from the take-out pipe 39. For example, the casting region 44 may be formed in the take-out tube 39. The casting region 44 is provided with a mold, whereby a cast solid state high purity polysilicon can be obtained. That is, molten silicon flowing from the slant pipe 33 and flowing into the take-out pipe 39 is injected into a mold (not shown) provided in the casting region 44 and cooled to obtain a cast polysilicon mass . In another example, if the extraction tube 39 is maintained at a predetermined temperature or higher, liquid polysilicon can be obtained, and the liquid polysilicon can be used in a subsequent process.

The extraction pipe 39 is provided with an exhaust gas recovery pipe 49 for recovering a mixture of the reaction gas and the reducing gas flowing into the extraction pipe 39 without precipitating silicon from the inclined pipe 33. The mixture recovered through the exhaust gas return pipe 49 can be recycled to the silicon deposition by separating into a reaction gas through separate separation and conversion processes.

In the apparatus according to the present invention, devices such as a horizontal pipe, a slanting pipe, and a sawtooth wire are made of materials such as molybdenum (Mo), tantalum (Ta) It is preferable to use a material.

Hereinafter, a method for producing polysilicon using the apparatus for producing polysilicon according to the present invention will be schematically described.

In order to produce polysilicon according to the present invention, the interior of the horizontal tube 32 is first evacuated. The horizontal tube 32 can be evacuated through the vacuum exhaust port 38 by using a vacuum pump (not shown). Next, the reaction gas and the reducing gas are introduced through the reaction gas inlet port 35 and the reducing gas inlet port 35, respectively. The reaction gas and the reducing gas are mixed in the mixing region 41 of the horizontal tube 32 and then continuously moved to the downstream side of the horizontal tube 32 to reach the dissociation region 42. Since the AC power is applied between the sawtooth wire 37 disposed in the dissociation region 42 and the electrode on the outer surface of the horizontal tube 32, a streamer plasma reaction occurs in the dissociation region. Thus, the mixed gas reaching the dissociation region 42 can be dissociated by energy from the streamer plasma reaction.

The dissociated mixed gas then flows into the precipitation region 43 of the inclined tube 33. Since the precipitation region 43 is heated to a temperature higher than the precipitation reaction temperature, polysilicon can be precipitated from the reaction of the mixed gas. The deposited polysilicon can move to the extraction pipe 39 in a solid state or a liquid state. It is possible to cast the polysilicon into a predetermined shape using a mold (not shown) in the casting region 44 of the takeout pipe 39 or to obtain the solid state polysilicon deposited in the inclined pipe 33 . The residual mixed gas not used for the precipitation action in the slant pipe 33 can be recovered through the exhaust gas recovery pipe 49 and recycled.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. There will be. Accordingly, the true scope of protection of the present invention should be determined only by the appended claims.

32. Horizontal pipe 33. Slope pipe
34. AC power source 35. Reaction gas inlet
36. Reduction gas inlet 37. Serrated wire

Claims (12)

A horizontal tube having an inner space through which a reaction gas and a reducing gas can flow;
A streamer plasma discharge means for dissociating the reaction gas and the reducing gas; And
And an inclined pipe disposed downstream of the horizontal pipe and capable of raising the internal temperature to a predetermined temperature,
Wherein said streamer plasma discharge means comprises:
A sawtooth wire including a wire portion extending in the longitudinal direction inside the horizontal tube and a toothed portion having a plurality of teeth projected radially at predetermined intervals along the wire portion;
An electrode formed on an outer surface of the horizontal tube;
A power source for applying an alternating current to the sawtooth wire and the electrode;
Wherein the reaction gas and the reducing gas are dissociated by a streamer plasma discharge generated between the sawtooth wire and the electrode. delete delete The method according to claim 1,
Wherein the horizontal tube includes a mixing region in which the reaction gas and the reducing gas are mixed and a dissociation region in which the mixed reaction gas and the reducing gas are dissociated. A device for producing polysilicon. The method according to claim 1,
Wherein the inclined tube includes a precipitation region in which the dissociated reaction gas and the reducing gas react with each other to precipitate polysilicon. The method according to claim 1,
Wherein the inclined pipe is provided with an electric coil for heating provided on the outer surface of the inclined pipe. The method according to claim 1,
Further comprising a take-out pipe on the downstream side of the inclined pipe, wherein the polysilicon deposited in the inclined pipe can be cast in the take-out pipe. The method according to claim 1,
Wherein the horizontal pipe, the inclined pipe, and the sawtooth wire are independently made of at least one of molybdenum (Mo) and tantalum (Ta). The method according to claim 1,
Wherein the reaction gas comprises any one of monosilane, silanization silane, TCS, and STC, and the reducing gas comprises hydrogen. Introducing a reaction gas and a reducing gas into a horizontal tube;
Mixing the reaction gas and the reducing gas in the horizontal tube;
Dissipating the mixed reaction gas and the reducing gas by causing a streamer plasma discharge in the horizontal tube; And
And causing the dissociated reaction gas and the reducing gas to react with each other by heating to a predetermined temperature or higher to precipitate polysilicon,
Wherein the streamer plasma discharge is caused by applying an alternating current between a sawtooth wire installed in the horizontal tube and an electrode disposed outside the horizontal tube. delete 11. The method of claim 10,
Wherein the reaction gas comprises any one of monosilane, silanization silane (TCS), and tetrachlorosilane (STC), and the reducing gas comprises hydrogen.

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