Silicon oxide removal apparatus and facility for recycling inert gas for use in silicon single crystal manufacturing apparatus

#The present invention relates to removal of silicon oxide contained in an inert gas discharged from a silicon single crystal manufacturing apparatus based on the Czochralski method (the CZ method) that manufactures a silicon single crystal for use in, for example, semiconductor devices and solar batteries, and to a facility for recycling an inert gas.

#Conventionally, a method of obtaining a silicon single crystal for use in, for example, semiconductor devices and solar batteries as a single crystal ingot by using the CZ method has been widely used. FIG. 5 shows a schematic view of a silicon single crystal manufacturing apparatus that is generally used. As shown in FIG. 5, in the silicon single crystal manufacturing apparatus 20, vertically movable crucibles 22 and 23 that accommodate a silicon melt 21, and a heater 24 that is arranged so as to surround the crucibles 22 and 23 are generally arranged in a main chamber 26 where a single crystal 25 is grown. A pulling chamber 27 for accommodating and taking out the grown single crystal 25 is continuously provided above the main chamber 26.

#For the purpose of discharging oxides generated in a furnace out of the furnace etc., an inert gas such as argon gas is introduced into the chambers from a gas inlet 28 provided at an upper portion of the pulling chamber 27. The inert gas is guided so as to flow near the single crystal 25 by using a graphite gas flow-guide cylinder 30, and discharged from a gas outlet 29. A seed crystal 31 is brought into contact with the silicon melt 21 and the single crystal 25 is then grown.

#FIG. 1 is a schematic view showing an example of the silicon oxide removal apparatus and facility for recycling an inert gas for use in a silicon single crystal manufacturing apparatus, according to the present invention;

#FIG. 2 is a schematic view showing an example of an ejector that can be used in the silicon oxide removal apparatus according to the present invention;

#FIG. 3 is a schematic view showing an example of a static mixer that can be used in the silicon oxide removal apparatus according to the present invention;

#Hereinafter, an embodiment of the present invention will be described, but the present invention is not restricted thereto.

#In recent years, as silicon single crystal manufacture has increased in scale, demand for an inert gas used in the manufacture, such as an argon gas, has increased. Effectively collecting and recycling the inert gas discharged from the silicon single crystal manufacturing apparatus has been accordingly important for reduction of cost. To realize this, it is necessary to effectively remove the silicon oxide contained in the discharged inert gas. For removal of the silicon oxide contained in the discharged inert gas, conventionally, a filter is used, or the inert gas is subjected to gas bubbling in water with a fine particle collector, such as a venturi scrubber.

#When the above conventional apparatus and method are used to remove the silicon oxide contained in the inert gas, however, the silicon oxide cannot be removed sufficiently since the silicon oxide is a fine powder of the order of several microns in size. It has been therefore expected to remove the silicon oxide more effectively. In addition, there is also a problem in that apparatus maintainability becomes low since the removed silicon oxide is a fine powder and its operation cost thus becomes high.