Patent Publication Number: US-2022228289-A1

Title: Raw material feed hopper and single crystal growth system

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to and the benefit of Korean Patent Application No. 10-2021-0007361, filed on Jan. 19, 2021, the disclosure of which is incorporated herein by reference in its entirety. 
     TECHNICAL FIELD 
     The present disclosure relates to a raw material feed hopper and a single crystal growth system capable of supplying a raw material. 
     BACKGROUND 
     A single crystal growth apparatus supplies solid polycrystalline silicon into a crucible, then heats the crucible to make a liquid silicon melt, and grows a single crystal ingot having a target diameter by putting a seed that agglomerates a seed crystal in the silicon melt, rotating it, and pulling it up at the same time. 
     Thus, a solid raw material is supplied to the single crystal growth apparatus before growing the ingot. In a method of supplying the solid raw material according to a shape of the solid raw material, the solid raw material may be supplied by vertically dropping from an upper center of the crucible or obliquely. 
     An example of a method of supplying a solid raw material is a raw material supply apparatus for single crystal growth disclosed in Korean Laid-Open Patent Publication No. 10-2018-0013584 A (published on Feb. 7, 2018), and in the raw material supply apparatus for single crystal growth, which is mounted on a mounting port of a chamber and additionally supplies solid fuel to a melt contained in a crucible for single crystal growth, the raw material supply apparatus for single crystal growth includes a tube which is hung at the mounting port of the chamber and in which a lower part is infiltrated into the melt of the crucible so as to guide the input of the solid raw material, and a cover provided inside the tube so as to be able to lift up and down and controlling the input of the solid raw material above a surface of the melt of the crucible. 
     Another example of a method of supplying the solid raw material is a recharge tube disclosed in Korean Laid-open Patent Publication No. 10-2020-0026247 A (published on Mar. 10, 2020). 
     The recharge tube is a recharge tube including a cylindrical member for accommodating a raw material and a conical valve for opening and closing an opening at a lower portion of the cylindrical member, wherein the cylindrical member has a lower conical opening, which is a conical opening whose inner diameter decreases downward, at a lower end of an inner circumferential surface, and in addition, the cylindrical member has an upper conical opening, which is a conical opening whose inner diameter decreases downward, below the lower conical opening at the lower end, and the valve is positioned between the lower conical opening and the upper conical opening. 
     SUMMARY 
     Technical Problem 
     A raw material supply apparatus for single crystal growth according to the related art has a problem in that dust may be generated in a hollow tube or a cylindrical member when a raw material is supplied into the hollow tube or the cylindrical member. 
     The present embodiment is directed to providing a raw material supply apparatus and a single crystal growth system in which dust generation may be minimized when a raw material is supplied into a hollow tube. 
     Technical Solution 
     In a raw material supply apparatus according to the present embodiment, a raw material feed hopper may include a hollow tube having a raw material accommodating space formed therein, a supporter supporting the hollow tube, a cone accommodated in the raw material accommodating space so as to be able to lift up and down, a rod connected to the cone, a connector connected to an upper portion of the rod, a lifting rod connected to the connector, and an elevator installed on the supporter for lifting up and down the lifting rod. 
     A gap may be formed between an outer circumference of the cone and an inner circumference of the hollow tube. 
     The raw material feed hopper may further include a dust stand provided under the supporter and facing a lower portion of the hollow tube and the raw material accommodating space. 
     The supporter may be provided with a hollow tube support. The hollow tube support may support the hollow tube so that the hollow tube is disposed at an angle that is obliquely laid with respect to the supporter. 
     The raw material feed hopper may further include a wheel disposed under the supporter. 
     The elevator may include a cylinder through which the lifting rod is guided. 
     An example of the elevator may include a driving source installed on the supporter, and a power transmission member connecting the driving source and the lifting rod. 
     An accommodating hole for accommodating the power transmission member may be formed in the cylinder. 
     Another example of the elevator may include a pressure regulator that regulates pressure inside the cylinder. 
     The elevator may lift up the cone to a first height in the hollow tube before the hollow tube is supplied with a raw material. 
     The first height may be a height closer to an upper end of the upper end and a lower end of the hollow tube. 
     The elevator may gradually lower a height of the cone while the raw material is supplied into the hollow tube. 
     The elevator may lift down the cone to a second height in the hollow tube before moving the hollow tube. 
     The second height may be higher than a lower end of the hollow tube. 
     The second height may be a height in which the cone is closer to the lower end of a center and the lower end of the hollow tube. 
     The raw material feed hopper may further include an operation unit for operating the elevator. 
     A single crystal growth system includes a raw material feed hopper and a single crystal growth apparatus. 
     The single crystal growth apparatus includes a crucible in which a space for accommodating the raw material dropped from the hollow tube is formed, and a heater for heating the crucible. 
     The raw material feed hopper may be moved around the single crystal growth apparatus, and may be moved above the crucible together with the hollow tube, cone, rod, and connector and the raw material. 
     Advantageous Effects 
     According to an embodiment of the present invention, a cone is lifted up from the inside of a hollow tube, a drop distance of a raw material can be minimized, and the generation of dust due to a drop impact can be minimized. 
     In addition, since the hollow tube is disposed on a supporter at an obliquely laid angle, the raw material drops along an inner circumference of the hollow tube, and the drop distance can be minimized. 
     Further, a defective rate of single crystal growth can be minimized by minimizing dust. 
     Furthermore, the drop distance of the raw material can be minimized, and damage and cracks in the hollow tube due to the impact of the raw material on the hollow tube can be minimized. 
     In addition, the raw material dropped from the hollow tube drops to a dust stand provided at a lower portion of the supporter, thereby minimizing contamination of a surrounding area, and preventing an accident due to dust. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a view illustrating a raw material feed hopper according to an embodiment of the present invention. 
         FIG. 2  is a view before the raw material feed hopper shown in  FIG. 1  is supplied with a raw material. 
         FIG. 3  is a view during the raw material feed hopper shown in  FIG. 2  is supplied with the raw material. 
         FIG. 4  is a view when the raw material feed hopper shown in  FIG. 3  is moved after the raw material is supplied. 
         FIG. 5  is a view when the hollow tube shown in  FIG. 4  supplies the raw material into the crucible. 
         FIG. 6  is a view illustrating a raw material feed hopper according to another embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     Hereinafter, the present embodiments will be described in detail with reference to the accompanying drawings. 
       FIG. 1  is a view illustrating a raw material feed hopper according to an embodiment of the present invention,  FIG. 2  is a view before the raw material feed hopper shown in  FIG. 1  is supplied with a raw material,  FIG. 3  is a view during the raw material feed hopper shown in  FIG. 2  is supplied with the raw material, and  FIG. 4  is a view when the raw material feed hopper shown in  FIG. 3  is moved after the raw material is supplied. 
     The raw material feed hopper may include a hollow tube  10 , a supporter  20 , a cone  30 , a rod  40 , a connector  50 , a lifting rod  60 , and an elevator  70 . 
     A raw material accommodating space  12  may be formed in the hollow tube  10 . The raw material accommodating space  12  may be formed inside the hollow tube  10 , and may be formed long in a longitudinal direction of the hollow tube  10 . 
     A raw material inlet  14  into which the raw material is introduced may be formed at an upper portion of the hollow tube  10 . A raw material outlet  16  through which the raw material is discharged may be formed a lower portion of the hollow tube  10 . 
     The raw material inlet  14  may be formed at an upper end  17  of the hollow tube  10 , and the raw material outlet  16  may be formed at a lower end  19  of the hollow tube  10 . 
     An example of a raw material supplied to the raw material accommodating space  12  of the hollow tube  10  may be polysilicon that may be introduced into a single crystal growth apparatus  100  (see  FIG. 5 ) to generate an ingot. 
     The raw material feed hopper may be a polysilicon filler that fills polysilicon into a crucible  110  (see  FIG. 5 ) of the single crystal growth apparatus  100 . 
     The raw material may be introduced into the raw material accommodating space  12  through the raw material inlet  14  of the hollow tube  10  from the outside, and may be temporarily stored by being accommodated in the raw material accommodating space  12  of the hollow tube  10 . The raw material may be moved by the hollow tube  10  and the cone  30  in a state of being accommodated in the raw material accommodating space  12 . 
     The raw material accommodated in the raw material accommodating space  12  may drop into the crucible  110  through the raw material outlet  16  when the hollow tube  10  is positioned above the crucible  110  (see  FIG. 6 ). 
     The supporter  20  may be positioned outside the hollow tube  10 . 
     The supporter  20  may support the hollow tube  10 . The hollow tube  10  may be separated from the supporter  20 , and may be moved over the crucible  110 , and the raw material may be moved onto the crucible  110  in a state of being separated from the supporter  20 . 
     The hollow tube  10  may be moved to a raw material input position together with the cone  30  while being put on the supporter  20 . At the raw material input position, the raw material may be introduced into the hollow tube  10 . 
     The hollow tube  10  may be moved near the crucible  110  together with the cone  30 , and may be moved above the crucible  110  together with the cone  30 . A robot or lifter may lift the hollow tube  10  placed on the supporter  20  near the crucible  110 , and may move the hollow tube  10  above the crucible  110  in order to supply raw materials into the crucible  110 . 
     The supporter  20  may be provided with a hollow tube support  22 . The hollow tube support  22  may support the hollow tube  10  so that the hollow tube  10  is disposed at an angle that is obliquely laid with respect to the supporter  20 . 
     The hollow tube  10  may be obliquely supported by the supporter  20  so as to have an acute angle of inclination with respect to a horizontal plane. 
     A raw material feeder (not shown) may introduce the raw material into the hollow tube  10  at the raw material input position. When the hollow tube  10  is at an obliquely laid angle, the raw material dropped from the raw material feeder to the hollow tube  10  does not drop directly to the cone  30 , and may drop along an inner circumference of the hollow tube  10 . 
     When the raw material directly drops to the cone  30 , dust may be excessive, but when the raw material drops along the inner circumference of the hollow tube  10 , a drop distance may be minimized, and generation of dust may be minimized. 
     The hollow tube support  22  may include an inclined surface  23 . The inclined surface  23  may have an inclination angle of an acute angle with respect to the horizontal surface. The inclined surface  23  may be formed at an upper portion of the supporter  20 . The inclined surface  23  may be formed to be flat or concave. 
     The hollow tube support  22  may include at least one roller  24  rotatably disposed on the supporter  20 . The roller  24  may be disposed at the upper portion of the supporter  20  to guide the hollow tube  10 . The roller  24  may be disposed on the inclined surface  23 . The roller  24  may assist the movement of the hollow tube  10  and may support the load of the supporter  22 . It is preferable that a plurality of rollers  24  are provided on the supporter  20 , and the plurality of rollers  24  may have different heights. 
     The hollow tube  10  may be placed on the roller  24  when the hollow tube support  22  includes the roller  24 , and the hollow tube  10  may be placed and supported on the inclined surface  23  when the hollow tube support  22  does not include the roller  24 . 
     The hollow tube support  22  may further include a stopper  25  for supporting so that the hollow tube  10  does not arbitrarily drop downward. 
     In an example of the hollow tube  10 , a flange  11  may protrude from one side of an outer circumference of the hollow tube  10 , and since the flange  11  is hooked on the stopper  25 , the hollow tube  10  does not arbitrarily drop downward. 
     In another example of the hollow tube  10 , a separate seating member is disposed under the raw material outlet  16  of the hollow tube  10 , and since the seating member is hooked on the stopper  25 , the hollow tube  10  does not arbitrarily drop downward. 
     An elevator mounting part  26  on which the elevator  70  is mounted may be formed on the supporter  20 . A driving source  74  of the elevator  70  may be mounted on the elevator mounting part  26 . The elevator mounting part  26  may be formed at the upper portion of the supporter  20 . 
     The raw material feed hopper may further include a wheel  28  disposed under the supporter  20 . When the raw material feed hopper further includes the wheel  28 , the raw material feed hopper may be moved as a whole together with a cart or the like, and the raw material feed hopper may be a cart-type raw material feed hopper or a raw material feed cart. 
     The cone  30  may be accommodated in the raw material accommodating space  12  to be lifting up and down. The cone  30  may be a cover blocking the raw material accommodating space  12 . 
     A gap G may be formed between an outer circumference of the cone  30  and the inner circumference of the hollow tube  10 . The cone  30  may be easily lifted up and down inside the hollow tube  10 . The gap G may be approximately 5 mm. 
     The rod  40  may be connected to the cone  30 . The lower portion of the rod  40  may be connected to the cone  30 . A part of the rod  40  may be positioned in the raw material accommodating space  12 , and may be lifted up and down by the connector  50  to adjust a height of the cone  30 . 
     The rod  40  may be moved together with the hollow tube  10  when the hollow tube  10  is moved over the crucible  110 . 
     The connector  50  may be connected to an upper portion of the rod  40 . The connector  50  may be detachably connected to the lifting rod  60 . When the connector  50  is connected to the lifting rod  60 , the lifting rod  60  may lift up and down the connector  50 . 
     The connector  50  may be separated from the lifting rod  60 , and when the hollow tube  10  is moved to the crucible  110 , the connector  50  may be moved together with the hollow tube  10 . The connector  50  may function as a hook member on which a robot or a lifter&#39;s hand is hooked. 
     The lifting rod  60  may be connected to the connector  50 . The lifting rod  60  may be connected to the connector  50  outside the hollow tube  10 . 
     The lifting rod  60  may include a connector connecting part  62  to which the connector  50  is detachably connected. 
     The lifting rod  60  may include a rod part  64  connected to the connector connecting part  62 . 
     The connector connecting part  62  and the rod part  64  may be lifted up and down outside the hollow tube  10 . 
     The connector connecting part  62  and the rod part  64  may be orthogonal to each other. 
     The rod part  64  may be parallel to the hollow tube  10  outside the hollow tube  10 . 
     The lifting rod  60  may remain in the supporter  20  together with the elevator  70  when the hollow tube  10  is moved over the crucible  110 . 
     The elevator  70  may adjust a height of the lifting rod  60  to adjust heights of the connector  50 , the rod  40 , and the cone  30 . That is, the elevator  70  may be a cone height adjusting mechanism. 
     The elevator  70  may be installed on the supporter  20 , and may lift up and down the lifting rod  60  next to the hollow tube  10 . The elevator  70  may be mounted on the elevator mounting part  26  of the supporter  20 , and may remain in the supporter  20  when the hollow tube  10  is moved over the crucible  110 . 
     The elevator  70  may include a cylinder  72  through which the lifting rod  60  is guided. 
     A part of the lifting rod  60  may be disposed inside the cylinder  72 . A part of the rod part  64  may be disposed inside the cylinder  72   
     An example of the elevator  70  may include the driving source  74  installed on the supporter  20  and power transmission members  76  and  78  that transmits the driving force of the driving source  74  to the lifting rod  60 . 
     The driving source  74  may be mounted on the elevator mounting part  26 . 
     The power transmission members  76  and  78  may connect the driving source  76  and the lifting rod  60 . 
     An example of the driving source  74  may be a motor in which a rotational shaft is rotated. When the driving source  74  is a motor, an example of the power transmission members  76  and  78  may include a gear. The power transmission members  76  and  78  may include a pinion  76  connected to the rotational shaft of the motor, and a rack  78  provided on the lifting rod  60 , in particular, the rod part  64 . 
     Another example of the driving source  74  may be a linear motor. When the driving source  74  is the linear motor, an example of the power transmission members  76  and  78  may include a linear guide. 
     An accommodating hole  73  for accommodating the power transmission members  76  and  78  may be formed in the cylinder  72 . 
     The driving source  74  may be operated to lift up and down the rod part  64  positioned in the cylinder  72  in a state of being disposed outside the cylinder  72 . 
     Before the hollow tube  10  is supplied with the raw material, the elevator  70  may raise the cone  30  to a first height H 1  in the hollow tube  10  as shown in  FIG. 2 . 
     The first height H 1  may be a height closer to the upper end  17  of the upper end  17  and the lower end  19  of the hollow tube  10 . 
     The cone  30  may receive the raw material supplied to the raw material inlet  14  of the hollow tube  10  while being raised to the first height H 1  by the elevator  70 . The raw material supplied to the raw material inlet  14  does not have a large drop because the height of the cone  30  is high, damage and breakage of the raw material may be minimized, and an original shape of the raw material may be maintained as much as possible. 
     While the raw material is supplied to the hollow tube  10 , the elevator  70  may gradually lower the height of the cone  30 , as shown in  FIG. 3 . As an amount of the raw material supplied to the raw material inlet  14  increases, the height of the cone  30  may be lowered so that a sufficient space may be secured inside the cone  30 . 
     A height of an upper end of the raw material in the hollow tube  10  may be high, and the raw material newly supplied to the raw material inlet  14  does not have a large drop because the height of the upper end of the raw material in the hollow tube  10  is high, and may be gradually stacked in the hollow tube  10 . 
     As described above, when the height of the cone  30  is gradually lowered, damage and breakage of the raw material may be minimized, and the original shape of the raw material may be maintained as much as possible. 
     The elevator  70  may move down the cone  30  to a second height H 2  in the hollow tube  10  as shown in  FIG. 4  before moving the hollow tube  10 . That is, after the cone  30  is moved down to the second height H 2  in the hollow tube  10 , the raw material feed hopper, in particular, the supporter  20  may move the hollow tube  10 . 
     The second height H 2  may be higher than the lower end  19  of the hollow tube  10 . The second height H 2  may be a height at which the raw material in the hollow tube  10  does not arbitrarily drop into the raw material outlet  16  and is stored in the hollow tube  10 . 
     The second height H 1  may be a height in which the cone  30  is closer to the lower end  19  of the center  18  and the lower end  19  of the hollow tube  10 . 
     The raw material feed hopper may further include a dust stand  80 . Dust separated from the raw material together with the raw material may be accommodated inside the hollow tube  10 , and the dust passes through the gap G between the outer circumference of the cone  30  and the inner circumference of the hollow tube  10 , and then may drop into the raw material outlet  16 . 
     The dust stand  80  may be provided at a position capable of receiving the dust dropped to the raw material outlet  16 . 
     The dust stand  80  may be provided the lower portion of the supporter  20 , and may face a lower portion of the hollow tube  10  and the raw material accommodating space  12 . The dust stand  80  may have an open upper surface, and a dust accommodating space may be formed therein. 
     The raw material feed hopper may further include an operation unit  90  for operating the elevator  70 . The operation unit  90  may include a button through which an operator may input an operation command, a stop command, an ascending command, a descending command, and the like. 
     The operation unit  90  may be provided to the supporter  20  or may be connected to the supporter  20  by an electric wire. The operation unit  90  may be a remote controller separated from the supporter  20 . 
     As shown in  FIG. 4 , in a state in which the cone  30  is moved down to the second height H 2  in the hollow tube  10 , the raw material feed hopper may be moved around the single crystal growth apparatus  100 . 
     When the raw material feed hopper is moved around the single crystal growth apparatus  100 , the robot or lifter may lift the hollow tube  10  and the connector  50  and move them onto the crucible  110 , and the hollow tube  10 , the cone  30 , the rod  40 , and the connector  50  and the raw material may be moved onto the crucible  110 . 
       FIG. 5  is a view when the hollow tube shown in  FIG. 4  supplies the raw material into the crucible. 
     The raw material feed hopper may be moved around the single crystal growth apparatus  100 . The single crystal growth apparatus  100  may form the single crystal growth system together with the raw material feed hopper. 
     The single crystal growth apparatus  100  may include the crucible  110  that receives the raw material through the hollow tube  10  and a heater  120  that heats the crucible  110 . 
     A space  112  in which the raw material dropped from the hollow tube  10  is accommodated may be formed inside the crucible  110 . 
     The single crystal growth apparatus may include a chamber  130 . The chamber  130  may have a space  132  in which the crucible  110  and the heater  120  are accommodated. 
     An example of the crucible  110  may be a quartz crucible, and the raw material may be heated inside the crucible  110  after dropping into the crucible  110  from the hollow tube  10 . 
     The heater  120  may heat the crucible  110  from the outside of the crucible  110 . The heater  120  may be disposed between the crucible  110  and the chamber  130 . 
     The single crystal growth apparatus may include a frame  140  disposed above the crucible  110  and on which the hollow tube  10  is seated. The single crystal growth apparatus may further include a hollow tube lifting mechanism for lifting the hollow tube  10 . 
     The single crystal growth apparatus may further include a connector holder  150  to which the connector  50  may be suspended. 
     The single crystal growth apparatus may include a connector holder lifting mechanism for lifting the connector holder  150 . 
     After the hollow tube  10 , the cone  30 , the rod  40 , the connector  50 , and the raw material are moved above the crucible  110 , the single crystal growth apparatus may raise the hollow tube  10  or lower the connector  50  to position the cone  30  below a lower end of the raw material outlet  16 . That is, all the raw material outlets  16  may be opened. 
     The raw material in the hollow tube  10  does drop into the space  112  of the crucible  110  through the gap between the raw material outlet  16  and the cone  30  as the cone  30  is positioned below the raw material outlet  16 . 
       FIG. 6  is a view illustrating a raw material feed hopper according to another embodiment of the present invention. 
     The raw material feed hopper of the embodiment may include an elevator  70 ′ for elevating the lifting rod  60 , as shown in  FIG. 6 , and the elevator  70 ′ may include a cylinder  72 ′ through which the lifting rod  60  is guided and a pressure regulator  74 ′ for controlling pressure inside the cylinder  72 ′. 
     The pressure regulator  74 ′ may be a hydraulic regulator that regulates hydraulic pressure inside the cylinder  72 ′ or a pneumatic regulator that regulates air pressure inside the cylinder  72 ′. 
     The pressure regulator  74 ′ may be connected to the cylinder  72 ′ and the tube  75 , and the cylinder  72 ′ and the pressure regulator  74 ′ are hydraulic cylinders or pneumatics capable of adjusting the height of the lifting rod  60 . 
     In the embodiment, a configuration and operation of the tube  10 , the supporter  20 , the cone  30 , the rod  40 , the connector  50 , and the lifting rod  60  other than the elevator  70 ′ are the same as or similar to the raw material feed hopper of one embodiment of the present invention, and thus, the same reference numerals are used, and detailed descriptions thereof are omitted in order to avoid redundant descriptions. 
     The above-described descriptions are merely illustrative of the technological spirit of the present invention, and various modifications and variations may be made by those having ordinary skill in the art to which the present invention pertains without departing from the essential characteristics of the present invention. 
     Therefore, the embodiments disclosed in the present invention are not intended to limit the technological spirit of the present invention, but the embodiments are intended to describe, and the spirit and scope of the present invention is not limited by such embodiments. 
     The protection scope of the present invention should be construed by the following claims, and all technological spirits within the equivalent scope thereof should be construed as being included in the scope of right of the present invention.