Patent Publication Number: US-9422929-B2

Title: Energy-saving silencer assembly, a semiconductor manufacturing vacuum pump with same and method for heating nitrogen gas

Description:
CROSS REFERENCE TO PRIOR APPLICATION 
     This application is a National Stage Patent Application of PCT International Patent Application No. PCT/KR2011/010229 (filed on Dec. 28, 2011) under 35 U.S.C. §371, which claims priority to Korean Patent Application No. 10-2011-0000590 (filed on Jan. 4, 2011), which are all hereby incorporated by reference in their entirety. 
     TECHNICAL FIELD 
     The present invention relates to a semiconductor manufacturing apparatus, and more particularly, to an energy-saving silencer assembly capable of solving a blockage problem caused by the solidification of byproducts and saving energy costs caused by the use of an additional heat source by using a high temperature of a surface of a silencer itself to heat nitrogen gas and supplying the heated nitrogen gas into the silencer, a semiconductor manufacturing vacuum pump having the energy-saving silencer assembly, and a method of heating nitrogen gas. 
     BACKGROUND ART 
     Generally, a semiconductor manufacturing process includes a fabrication process and an assembly process. The fabrication process means a process of manufacturing semiconductor chips by depositing thin films on a wafer in various process chambers and selectively etching the deposited films in a repeated way to form a predetermined pattern. The assembly process means a process of individually separating the chips manufactured in the fabrication process and then coupling the individual chip to a lead frame to assemble a final product. 
     At this time, the process of depositing thin films on a wafer or etching the films deposited on the wafer is performed at high temperature by using harmful gases such as silane, arsine, and boron chloride and process gases such as hydrogen in a process chamber. While such a process is performed, a large amount of various pyrophoric gases and byproduct gas containing harmful components and corrosive impurities are generated in the process chamber. 
     Thus, a semiconductor manufacturing apparatus is provided with a scrubber, which purifies byproduct gas discharged from a process chamber and discharges the purified byproduct gas to the atmosphere, at a downstream side of a vacuum pump for making the process chamber into a vacuous state. 
     However, while flowing from the process chamber to the vacuum pump and the scrubber via pipes  15   a  and  15   b  respectively, the harmful byproduct gas generated from the process chamber is easily solidified and accumulated, thereby resulting in blockage. 
     Thus, in order to solve the blockage problem caused by the solidification of byproduct gas, a nitrogen gas injection device  12  for injecting a high temperature nitrogen gas into a pipe in which a byproduct gas flows, particularly a pipe of a discharge side of a vacuum pump has been developed as disclosed in Korean Laid-open Patent Publication No. 2005-88649. 
     However, the conventional nitrogen gas injection device  12  which is provided as an external type had a limitation in that a blockage problem in a silencer  4  installed inside the vacuum pump is not solved. The silencer  4  is installed to suppress noise in the vacuum pump. However, since the silencer  4  is connected to a discharging portion  3  of a pump section  2  for performing pumping operation and thus positioned at a point which a large amount of byproducts pass through at once, the silencer  4  is always exposed to the blockage problem caused by the byproduct, but there is no obvious solution. 
     DISCLOSURE 
     Technical Problem 
     Accordingly, the present invention is conceived to solve the aforementioned problems in the prior art. An object of the present invention is to provide an energy-saving silencer assembly capable of solving a blockage problem caused by the solidification of byproducts and saving energy costs caused by the use of an additional heat source by using a high temperature of a surface of a silencer itself to heat nitrogen gas and supplying the heated nitrogen gas into the silencer, a semiconductor manufacturing vacuum pump having the energy-saving silencer assembly, and a method of heating nitrogen gas. 
     Technical Solution 
     According to an aspect of the present invention for achieving the objects, there is provided a silencer assembly of a semiconductor manufacturing vacuum pump for removing noise of byproduct gas pumped in the vacuum pump, which includes a silencer connected to a discharge side of a pump section for pumping byproduct gas in the vacuum pump and making the pumped byproduct gas pass through from a rear end portion to a front end portion; an outer pipe surrounding an outer peripheral surface of the silencer with a spacing therebetween to provide a heating space between the silencer and the outer pipe; a nitrogen gas supply section for supplying nitrogen gas to the heating space; and a nitrogen gas injection section for injecting into the silencer the nitrogen gas heated by being brought into contact with the outer peripheral surface of the silencer in the heating space. 
     The heating space may be further provided with a guide wire wound in a spiral around the outer peripheral surface of the silencer to guide the flow of nitrogen gas. 
     The nitrogen gas supply section may supply the nitrogen gas from a front end portion of the outer pipe, and the nitrogen gas injection section may inject the heated nitrogen gas at the rear end portion of the silencer. 
     The nitrogen gas supply section may be provided as a preheating pipe installed along a lengthwise direction from a rear end portion to the front end portion of the outer pipe in a position adjacent to an outer peripheral surface of the outer pipe, a nitrogen gas inlet port of the preheating pipe may be positioned at a rear end portion thereof, and a nitrogen gas outlet port for supplying the nitrogen gas to the heating space of the outer pipe may be positioned at the front end portion of the preheating pipe. 
     The nitrogen gas injection section may include a body defining a chamber surrounding an outside of the rear end portion of the silencer with a spacing therebetween to be supplied with the nitrogen gas heated from the heating space, and an injection nozzle for injecting the nitrogen gas introduced into the chamber into the silencer. 
     An injection hole of the injection nozzle may be formed in a position protruding from an inner peripheral surface of the silencer to inject the nitrogen gas in a flow direction of byproduct gas. 
     A semiconductor manufacturing vacuum pump according to the present invention includes the aforementioned silencer assembly. 
     A method of heating nitrogen gas according to the present invention, which is a method of heating nitrogen gas injected for preventing byproduct gas from being solidified, includes heating nitrogen gas supplied from the outside by being brought into contact with an outer peripheral surface of a silencer of a vacuum pump. 
     The nitrogen gas may be guided to flow in a spiral along the outer peripheral surface of the silencer. 
     The nitrogen gas may be preheated before being brought into contact with the outer peripheral surface of the silencer. 
     Advantageous Effects 
     According to an energy-saving silencer assembly, a semiconductor manufacturing vacuum pump having the same and a method of heating nitrogen gas of the present invention, it is possible to solve a blockage problem caused by the solidification of byproducts by using a high temperature of a surface of a silencer itself to heat nitrogen gas and supplying the heated nitrogen gas into the silencer. 
     In addition, according to the present invention, nitrogen gas is trapped in a limited space defined by a double pipe structure having an outer pipe surrounding the silencer with a spacing therebetween, thereby being capable of more effectively bringing the nitrogen gas into contact with an outer peripheral surface of the silencer. 
     Further, according to the present invention, a guide wire is provided so that the nitrogen gas can be in contact with a larger area of the outer peripheral surface of the silencer for a longer time. 
     Furthermore, according to the present invention, there is provided a preheating pipe for preheating nitrogen gas so that cold nitrogen gas is not brought into immediate contact with the surface of the silencer, thereby preventing the byproducts flowing in the silencer from being solidified. 
    
    
     
       DESCRIPTION OF DRAWINGS 
         FIG. 1  is a view illustrating a prior art; 
         FIG. 2  is a view of the configuration of a vacuum pump illustrating the prior art; 
         FIG. 3  is a perspective view of a silencer assembly according to the present invention; 
         FIG. 4  is a sectional view illustrating the configuration of the silencer assembly according to the present invention; and 
         FIG. 5  is a partially cutaway view illustrating the operation of the silencer assembly according to the present invention. 
     
    
    
     BEST MODE 
     Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the accompanying drawings. 
     A silencer assembly according to the present invention, which is included in a semiconductor manufacturing vacuum pump, is configured so that nitrogen gas for preventing solidification of byproducts is heated without an additional heat source using the surface temperature of an outer peripheral surface of a silencer in a high temperature state. According to this configuration, since a heat source necessary for heating nitrogen gas need not be additionally provided, it is possible to save an enormous amount of energy. 
     Hereinafter, the configuration of the silencer assembly according to the present invention will be described. 
       FIG. 3  is a perspective view of a silencer assembly according to the present invention, and  FIG. 4  is a sectional view illustrating the configuration of the silencer assembly according to the present invention. 
     As shown in the figures, the silencer assembly according to the present invention includes a silencer  110 , an outer pipe  120  surrounding an outer peripheral surface of the silencer  110  with a spacing therebetween to define a heating space  120   a , a preheating pipe  130  that is a nitrogen gas supply section for supplying nitrogen gas from the outside, a guide wire  140  for guiding the flow of nitrogen gas in the heating space  120   a , and a nitrogen gas injection section  150  for injecting the nitrogen gas heated in the heating space  120   a  into the silencer  110 . 
     The present invention including such components has a core feature in that the heating space  120   a  is provided by a double pipe structure consisting of the silencer  110  and the outer pipe  120  and nitrogen gas is introduced into the heating space  120   a  to be brought into contact with the outer peripheral surface of the silencer  110 , thereby heating the nitrogen gas to a high temperature. 
     Hereinafter, the present invention will be described in more detail with a focus on the above components. 
     First, the silencer  110  is connected to a discharge side of a pump section for pumping byproduct gas in the vacuum pump to make the pumped byproduct gas pass through from a rear end portion to a front end portion. 
     In addition, the outer pipe  120  surrounds the outer peripheral surface of the silencer  110  with a spacing therebetween to provide the heating space  120   a  between the silencer  110  and the outer pipe  120 . Accordingly, a double pipe structure having the heating space  120   a  is defined by the silencer  110  and the outer pipe  120 , and the nitrogen gas injected into the heating space  120   a  is brought into contact with the outer peripheral surface of the silencer  110 . In this case, the silencer  110  having a significantly high temperature in the vacuum pump as well known causes the nitrogen gas in contact with the outer peripheral surface of the silencer  110  to be smoothly heated to a high temperature. 
     The preheating pipe  130 , which is the nitrogen gas supply section, performs a function of supplying nitrogen gas to the heating space  120   a  as described above. To this end, the preheating pipe  130  is installed along a lengthwise direction of the outer pipe  120  from the rear end portion to the front end portion of the outer pipe  120  in a position adjacent to an outer peripheral surface of the outer pipe  120 . Here, a nitrogen gas inlet port  131  of the preheating pipe  130  is positioned at the rear end portion thereof, and a nitrogen gas outlet port  133  for supplying the nitrogen gas to the heating space  120   a  of the outer pipe  120  is positioned at the front end portion of the preheating pipe  130 . 
     According to the configuration of the preheating pipe  130 , before nitrogen gas supplied from the outside is introduced into the heating space  120   a , the nitrogen gas is preheated in advance while flowing along the inner space of the preheating pipe  130 . If the nitrogen gas is preheated before being introduced into the heating space  120   a , it is possible to prevent the cold nitrogen gas from being brought into abrupt contact with the outer peripheral surface of the silencer  110 . If the cold nitrogen gas is brought into immediate contact with the outer peripheral surface of the silencer  110 , it is apprehended that the byproduct gas flowing in the silencer  110  is locally influenced thereby being solidified. 
     The nitrogen gas injection section  150  serves to inject into the silencer  110  the nitrogen gas heated by bringing it into contact with the outer peripheral surface of the silencer  110  in the heating space  120   a . To this end, the nitrogen gas injection section  150  includes a body defining chambers  151  and  155  surrounding the outside of the rear end portion of the silencer  110  with a spacing therebetween to be supplied with the nitrogen gas heated from the heating space  120   a , and an injection nozzle  157  for injecting the nitrogen gas introduced into the chambers  151  and  155  into the silencer  110 . 
     Here, the body of the nitrogen gas injection section  150  is coupled to or provided integrally with the rear end portion of the silencer  110  and has a large hollow in communication with the silencer  110  in the center of the body. In addition, the chambers  151  and  155  of the body include the first chamber  151  and the second chamber  155  for successively receiving the nitrogen gas from the heating space  120   a , and the two chambers  151  and  155  are in communication with each other through a communication hole  153 . 
     Here, the injection nozzle  157  is provided with an injection hole  157   a , which is formed to face the front in a position protruding from an inner peripheral surface of the hollow of the body of the nitrogen gas injection section  150 . Such an injection hole  157   a  of the injection nozzle  157  can inject the nitrogen gas in the same direction as the flow direction of the byproduct gas flowing within the silencer  110  and have an ejector effect rather than hinder the flow of the byproduct gas by the injection of the nitrogen gas, thereby being capable of accelerating the flow of the byproduct gas. 
     The guide wire  140  is provided to be wound in a spiral around the outer peripheral surface of the silencer  110  in the heating space  120   a . Here, the guide wire  140  has a thickness equal or similar to the height of the heating space  120   a . If the guide wire  140  is provided as described above, the nitrogen gas flowing in the heating space  120   a  flows not simply straight but in a spiral along the outer peripheral surface of the silencer  110  while being guided by the guide wire  140 . Thus, the contact area and the contact time of the nitrogen gas with the surface of the silencer  110  in the heating space  120   a  are increased, thereby improving heat exchange efficiency. 
     For reference, unmentioned reference numeral  191  designates a connector for connecting to the pump section. 
     The operation of the silencer assembly according to the present invention will be described in detail with reference to the accompanying drawings. 
     First, in a state that the vacuum pump operates, the silencer  110  reaches a state heated to a high temperature by a high temperature atmosphere in the vacuum pump. 
     If the silencer  110  itself is heated to a high temperature as described above, the heating space  120   a  defined between the silencer  110  and the outer pipe  120  also has a high temperature atmosphere, and although having a lower temperature than that, the preheating pipe  130  communicating with the heating space  120   a  also has a relatively high temperature atmosphere. 
     In such a state, if nitrogen gas is supplied to the preheating pipe  130  from the outside ({circle around ( 1 )}), before the nitrogen gas is introduced into the heating space  120   a , the nitrogen gas is preheated and a first temperature increase is achieved while flowing in the preheating pipe  130  ({circle around ( 2 )}). 
     Thereafter, the nitrogen gas having the first temperature increase achieved in the preheating pipe  130  is introduced into the heating space  120   a  defined between the silencer  110  and the outer pipe  120  through the nitrogen gas outlet port  133  at the front end portion of the preheating pipe  130  ({circle around ( 3 )}). 
     Then, the nitrogen gas introduced into the heating space  120   a  flows backward while being in contact with the outer peripheral surface of the silencer  110  in the heating space  120   a  ({circle around ( 4 )}). In such a case, the nitrogen gas introduced into the heating space  120   a  flows in a spiral along the guide wire  140  and thus the contact area and the contact time with the silencer  110  are increased. 
     As described above, the nitrogen gas introduced into the heating space  120   a  flows while being in contact with the high temperature outer peripheral surface of the silencer  110  and then becomes in a state heated to a significantly high temperature when the nitrogen gas reaches the rear end portion of the heating space  120   a.    
     Thereafter, the nitrogen gas heated at a high temperature in the heating space  120   a  passes through the first chamber  151  and the second chamber  155  of the body of the nitrogen gas injection section  150  ({circle around ( 5 )}) and then is injected into the silencer  110  through the injection hole  157   a  of the injection nozzle  157  ({circle around ( 6 )}). The nitrogen gas injected in this way is injected in the same direction as the flow direction of the byproduct gas flowing within the silencer  110  and thus is mixed with the byproduct gas without hindering the flow thereof, thereby preventing the solidification of the byproduct gas and helping the byproduct gas flow by the ejector effect. 
     Although the preferred embodiments of the present invention have been described, the present invention may use various changes, modifications and equivalents. It will be apparent that the present invention may be equivalently applied by appropriately modifying the aforementioned embodiments. Accordingly, the above descriptions do not limit the scope of the present invention defined by the appended claims.