Abstract:
The present invention relates to a pipe joint structure for a semiconductor processing, comprising: a first pipe joint; a second pipe joint; a gasket inserted into adjacent surfaces of the first pipe joint and the second pipe joint; and a screw for bringing the adjacent surfaces of the first pipe joint and the second pipe joint into close contact with the gasket, wherein the first pipe joint has an annular indented groove formed in the center of the adjacent surface thereof, the second pipe joint has a protrusion portion formed on the adjacent surface thereof so as to correspond to the indented groove, and the gasket has a second protrusion portion and a second indented groove which are respectively formed on both side surfaces thereof so as to correspond to the indented groove and the protrusion portion.

Description:
REFERENCE TO RELATED APPLICATIONS 
       [0001]    This is a continuation of pending International Patent Application PCT/KR2011/009417 filed on Dec. 7, 2011, which designates the United States and claims priority of Korean Patent Application No. 10-2011-0130005 filed on Dec. 7, 2011, the entire contents of which are incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to a pipe joint structure for semiconductor processing, and more particularly to a joint structure of piping components through which source gases such as helium, nitrogen dioxide, oxygen, hydrogen, ammonia and the like used in a semiconductor manufacturing line are transferred. 
       BACKGROUND OF THE INVENTION 
       [0003]    In semiconductor processing, a pipe joint structure for semiconductor processing, which is used in a gas cabinet, a gas purifier and in principal procedures of MOCVD, must have a fitting surface having an improved surface roughness through electropolishing in order to block introduction of impurities and to maintain the purity of raw gas. Furthermore, an assembling operation of the pipe joint structure has to be performed in a clean room under highly sterile conditions because the pipe joint structure affects semiconductor yields. 
         [0004]    Accordingly, in order that a pipe joint structure designed to transfer raw gas used in semiconductor manufacturing lines does not cause a decrease in the purity of the raw gas, various techniques are being developed. 
         [0005]    The related arts may include U.S. Pat. No. 7,497,482 (registered Mar. 3, 2009, entitled ‘Pipe Joint), U.S. Pat. No. 5,366,261 (registered Nov. 22, 1994, entitled ‘Pipe Joint with a Gasket Retainer) and the like. 
         [0006]      FIG. 1  is a cross-sectional view showing a pipe joint structure which is used in a conventional semiconductor processing. 
         [0007]    As shown in  FIG. 1 , a gasket  30  is interposed between abutting surfaces of two connecting pipes  10 ,  20  to provide a sealing coupling for air tightness. 
         [0008]    The conventional pipe joint structure has disadvantages in that a sealing portion has a small surface area, particles are generated and introduced into the connecting pipes the gasket and the abutting surfaces are engaged, and a dead space D occurs between the coupled pipes. 
       SUMMARY OF THE INVENTION 
       [0009]    Accordingly, the present invention is intended to provide a pipe joint structure for semiconductor processing which is designed to minimize introduction of particles generated during a coupling procedure of connecting pipes and to prevent occurrence of a dead space. 
         [0010]    A pipe joint structure for semiconductor processing according to an aspect of the present invention includes a first connecting pipe, a second connecting pipe, a gasket interposed between abutting surfaces of the first and second connecting pipes, and a fastening unit which causes the abutting surfaces of the first and second connecting pipes to come into close contact with the gasket, wherein the first connecting pipe includes an annular groove intermediately formed along the abutting surface thereof, and the second connecting pipe includes an annular protrusion formed along the abutting surface thereof to correspond to the annular groove, and wherein the gasket includes a second annular protrusion and a second annular groove formed on opposite surfaces thereof which correspond to the annular groove and the annular protrusion, respectively. 
         [0011]    Preferably, an internal diameter of the gasket is equal to internal diameters of the first and second connecting pipes. 
         [0012]    Preferably, when radially internal surfaces L 1 , L 2  of the abutting surfaces of the gasket at which the second annular protrusion and the second annular groove are formed come into contact with radially internal surfaces S 1 , S 2  of the first and second connecting pipes at which the annular groove and the annular protrusion are formed, a clearance G 2  occurs between the annular protrusion and the second annular groove, and a clearance G 3 , which is defined between a radially external surface L 3  at which the second annular groove is formed and a radially external surface S 4  at which the annular protrusion is formed, is larger than the clearance G 2  defined between the annular protrusion and the second annular groove. 
         [0013]    Preferably, the annular protrusion includes a curved surface formed at a radially internal area and gently curved, and an inclined surface formed at a radially external area and steeply inclined. 
         [0014]    Preferably, the second annular groove includes inclined surfaces formed at radially internal and external walls and a flat bottom surface. 
         [0015]    Preferably, a pipe joint structure for semiconductor processing according to another aspect of the present invention includes a first connecting pipe, a second connecting pipe, a gasket interposed between abutting surfaces of the first and second connecting pipes, and a fastening unit which causes the abutting surfaces of the first and second connecting pipes to come into close contact with the gasket, wherein annular protrusions are intermediately formed on abutting surfaces of the first and second connecting pipes, respectively, and annular grooves corresponding to the annular protrusions are formed on the opposite surfaces of the gasket. 
         [0016]    Preferably, the annular protrusions are configured such that curved surfaces are formed at a radially internal area and gently curved and inclined surfaces are formed at radially external area and steeply inclined. 
         [0017]    Preferably, the annular groove includes inclined surfaces formed at radially internal and external walls and a flat bottom surface. 
         [0018]    A pipe joint structure for semiconductor processing according to the present invention offers advantages in that the pipe joint structure includes a gasket and first and second connecting pipes having the same inner diameter so as to minimize occurrence of a dead space, the first and second connecting pipes include an annular groove and an annular protrusion intermediately formed on abutting surfaces thereof, respectively, and the gasket includes a second annular protrusion and a second annular groove which correspond to the annular groove and protrusion of the connecting pipes, thereby increasing a surface area of a sealing portion resulting in the prevention of gas leakage and providing a continuous contact between the gasket and the connecting pipes resulting in minimization of occurrence of particles and blocking the introduction of particles. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]      FIG. 1  is a cross-sectional view showing a pipe joint structure which is used in a conventional semiconductor processing; 
           [0020]      FIG. 2  is an exploded perspective view showing a pipe joint for semiconductor processing according to a preferred embodiment of the present invention; 
           [0021]      FIG. 3  is a cross-sectional view showing the pipe joint for semiconductor processing according to the preferred embodiment of present invention; 
           [0022]      FIG. 4  is an enlarged view of circle A of  FIG. 3 , which is exploded; 
           [0023]      FIGS. 5   a  to  5   d  are cross-sectional views showing a connecting operation of the pipe joint according to this embodiment of the present invention; 
           [0024]      FIG. 6  is a cross-sectional view of a pipe joint structure according to another preferred embodiment of the present invention; and 
           [0025]      FIG. 7  is a cross-sectional view of the pipe joint structure in which components thereof are engaged with each other. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0026]    A preferred embodiment of the present invention will now be explained in detail with reference to the accompanying drawings. 
         [0027]      FIG. 2  is an exploded perspective view showing a pipe joint for semiconductor processing according to a preferred embodiment of the present invention. 
         [0028]    As illustrated in  FIG. 2 , the pipe joint for semiconductor processing according to the present invention includes a first connecting pipe  10 , a second connecting pipe  20 , a gasket  30  interposed between abutting surfaces of the first and second connecting pipes  10 ,  20 , and a fastening unit  40  which causes the abutting surfaces of the first and second connecting pipes  10 ,  20  to come into close contact with the gasket  30 , in which the fastening unit  40  is composed of a male thread part  42  and a female thread part  44 . The pipe joint may further include a slip ring  50  for antifriction. 
         [0029]    The first connecting pipe  10  includes an annular groove  12  intermediately formed along the abutting surface thereof, and the second connecting pipe  20  includes an annular protrusion (not shown) formed along the abutting surface thereof to correspond to the annular groove  12 . The gasket  30  includes a second annular protrusion  32  and a second annular groove  34  formed on opposite surfaces thereof which correspond to the annular groove  12  and the annular protrusion, respectively. 
         [0030]      FIG. 3  is a cross-sectional view showing the pipe joint for semiconductor processing according to the preferred embodiment of present invention. 
         [0031]    As illustrated in  FIG. 3 , the pipe joint according to this embodiment of the present is substantially identical to a conventional pipe joint in that air tightness between the first and second connecting pipes is accomplished by virtue of the close contact between the abutting surfaces of the first and second connecting pipes  10 ,  20 . 
         [0032]    The pipe joint structure according to this embodiment of the present invention may be applied to a double mate type configuration as well as the single mate type configuration as shown in  FIG. 3 . 
         [0033]    In particular, as shown in  FIG. 3 , an internal diameter (D) of the gasket  30  is designed to be equal to internal diameters (D 1 , D 2 ) of the first and second connecting pipes  10 ,  20  so as not to form a dead space and thus to prevent the deterioration of the raw gas purity. 
         [0034]      FIG. 4  is an enlarged view of circle A of  FIG. 3 , which is exploded. 
         [0035]    As illustrated in  FIG. 4 , the first connecting pipe  10  includes the annular groove  12  intermediately formed along the abutting surface thereof, and the second connecting pipe  20  includes the annular protrusion  22  formed along the abutting surface thereof to correspond to the annular groove  12 . The gasket  30  includes a second annular protrusion  32  and a second annular groove  34  formed on opposite surfaces thereof which correspond to the annular groove  12  and annular protrusion  22 , respectively. 
         [0036]    The annular protrusion  22  includes a curved surface  22   b  formed at a radially internal area and gently curved, and an inclined surface  22   a  formed at a radially external area and steeply inclined. 
         [0037]    The second annular groove  34  includes inclined surfaces  34   a  formed at radially internal and external walls and a flat bottom surface  34   b.    
         [0038]      FIGS. 5   a  to  5   d  are cross-sectional views showing a connecting operation of the pipe joint according to this embodiment of the present invention. 
         [0039]      FIG. 5   a  shows the pipe joint structure according to this embodiment in which the opposite surfaces of the gasket begin to come into contact with both abutting surfaces of the first and second connecting pipes. 
         [0040]    As shown in  FIG. 5   a , when radially internal surfaces L 1 , L 2  of the abutting surfaces of the gasket at which the second annular protrusion and the second annular groove are formed come into contact with radially internal surfaces S 1 , S 2  of the first and second connecting pipes  10 ,  20  at which the annular groove and the annular protrusion are formed, a clearance G 2  occurs between the annular protrusion and the second annular groove, and a clearance G 3 , which is defined between a radially external surface L 3  at which the second annular groove is formed and a radially external surface S 4  at which the annular protrusion is formed, is larger than the clearance G 2  defined between the annular protrusion and the second annular groove. 
         [0041]    As a result, the contact between the gasket and both the first and second connecting pipes begins from the radially internal surfaces, thereby reliably preventing particles created during the contact procedure from being introduced into the connecting pipes. 
         [0042]      FIG. 5   b  shows the pipe joint structure in which components of the pipe joint are in maximally close contact through adjustment of the fastening unit by hand. 
         [0043]    In  FIG. 5   b , the radially internal surfaces L 1 , L 2  of the abutting surfaces of the gasket at which the second annular protrusion and the second annular groove are in sealing engagement with the radially internal surfaces S 1 , S 2  of the first and second connecting pipes  10 ,  20  at which the annular groove and the annular protrusion are formed, and the annular groove and the second annular groove are in contact with the annular protrusion and the second protrusion. The clearance G 3 , which is defined between a radially external surface L 3  at which the second annular groove is formed and a radially external surface S 4  at which the annular protrusion is formed, has a value smaller than that of the clearance as shown in  FIG. 5   a.    
         [0044]      FIG. 5   c  shows the pipe joint in which the pipe components are further fastened using a mechanical device from the conditions shown in  FIG. 5   b . At this point, the annular groove and the second annular groove are in sealing engagement with the annular protrusion and the second annular protrusion, and the radially external surface L 3  at which the second annular groove is formed is in contact with the radially external surface S 4  at which the annular protrusion is formed. 
         [0045]    A gap C 1  defined between the second annular protrusion and the annular groove and a gap C 2  defined between the annular protrusion and the second annular groove, as shown in  FIG. 5   b , are fully filled with the deformed portion of the gasket, as shown in  FIG. 5   c.    
         [0046]    Since the gasket typically has a 150-170 Hv of hardness which is lower than that of the pipe which is 300 Hv or higher, the gaps can be filled with the deformed gasket. 
         [0047]      FIG. 5   d  shows the pipe joint in which the pipe components are still further fastened using a mechanical device from the conditions shown in  FIG. 5   c . At this point, the radially external surface of the gasket at which the second annular groove is formed is also in sealing engagement with the radially external surface of the second connecting pipe at which the annular protrusion is formed, and thus the opposite surfaces of the gasket are in close contact with the abutting surfaces of the first and second connecting pipes. 
         [0048]    Another embodiment of the present invention will now be explained. 
         [0049]      FIG. 6  is a cross-sectional view of a pipe joint structure according to another preferred embodiment of the present invention, and  FIG. 7  is a cross-sectional view of the pipe joint structure in which components thereof are engaged with each other. 
         [0050]    In this embodiment of the present invention shown in  FIG. 6 , annular protrusions  12 ,  22  are intermediately formed on abutting surfaces of the first and second connecting pipes  10 ,  20 , respectively, and annular grooves  34  corresponding to the annular protrusions  12 ,  22  are formed on the opposite surfaces of a gasket  30 . 
         [0051]    This embodiment is substantially identical to the above embodiment in that the annular protrusions  12 ,  22  are configured such that curved surfaces are formed at a radially internal area and gently curved and inclined surfaces are formed at radially external area and steeply inclined. The annular groove  34  includes inclined surfaces formed at radially internal and external walls and a flat bottom surface. 
         [0052]    As illustrated in  FIG. 7 , when radially internal surfaces S 1  of connecting pipes at which the annular protrusions are formed come into contact with radially internal surfaces L 1  of the gasket at which the annular grooves are formed, a constant clearance G 2  occurs between the annular groove and the annular protrusion, and a clearance defined between the radially external surface at which the annular groove is formed and the radially external surface of the connecting pipe at which the annular protrusion is formed is larger than the clearance G 2 . 
         [0053]    Upon fully fastening the pipe joint, a clearance G 4  between the inner ends of the connecting pipes is preferably minimized so as to prevent the pipe joint from being excessively fastened. More specifically, contact between inner ends of both connecting pipes having the same hardness prevents the excessive fastening. 
         [0054]    Consequently, the contact between the gasket and both the connecting pipes begins from the radially internal area, thus reliably preventing particles created during the contact procedure from being introduced into the connecting pipes. 
         [0055]    As described above, the technical idea of the present invention resides in provision of a pipe joint structure for semiconductor processing. While the present invention has been described with reference to the preferred embodiments shown in the accompanying drawings, the embodiments are provided for illustrative purposes, and the true scope of the invention is therefore to be determined solely by the appended claims. 
         [0056]    The present invention relates to a pipe joint structure for semiconductor processing, and may be applied to a joint structure of piping components through which source gases such as helium, nitrogen dioxide, oxygen, hydrogen, ammonia and the like used in a semiconductor manufacturing line are transferred.