Abstract:
A high purity chemical delivery system is provided that connects a high purity chemical container to a high purity chemical utilization point and that comprises three manifolds, each of the manifolds having a plurality of diaphragm valves. The inventive system enables rapid clean out and purge after the container is replaced by means of a plurality of vacuum and purge cycles, which remove residual chemical and entrapped impurities while reduced manufacturing downtimes compared with systems in the prior art.

Description:
STATEMENT REGARDING FEDERALLY SPONSORED REASEARCH AND DEVELOPMENT 
   Not applicable. 
   REFERENCE TO A COMPUTER LISTING, A TABLE, OR A COMPUTER PROGRAM LISTING COMPACT DISK APPENDIX 
   Not applicable. 
   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention concerns a high purity chemical delivery system, and, more particularly, a high purity chemical delivery system enabling a rapid clean out and purge of any high purity chemical residues. 
   2. Description of Related Art 
   High purity chemical delivery systems are typically composed of manifolds having diaphragm valves and low dead space connectors. In the semiconductor industry, for instance, low vapor pressure high purity chemicals such as tetrakis (dymethilamino) titanium (TDMAT), tetrakis (diethylamino) titanium (TDEAT), tantalum pentaethoxide (TAETO), copper hexafluoroacetylacetonate-trimethylvinylsilane (Cu(hfac)TMVS), tetramethyltetracyclosiloxane (TMCTS), tetraethyl ortosilicate (TEOS), and trimethylphosphate (TMP) are delivered from primary storage canisters to process tools or to secondary storage canisters by means of manifolds that incorporate a plurality of diaphragm valves and that regulate the flow of the chemicals during ordinary process conditions and the flow of pressurized gases and of vacuum during purge cycles. These manifolds are detachably connected by low dead space connectors, such as VCR and low obstruction fittings, in order to minimize any entrapments of the high purity chemical within the dead spaces of the connectors and thereby reduce purge cycles. 
   When a storage container has exhausted the supply of high purity chemical and must be replaced, the delivery system connected to the container must be thoroughly purged after the new container is installed, in order to remove any impurities and any ambient gases that have entered the system during the canister replacement process. Due to the high purity levels required, these purge cycles are extremely time consuming causing manufacturing costs to increase due to the related manufacturing down-time and to the costs of the purge materials. 
   Therefore, there is a need for a high purity chemical delivery system minimizing the time required for clean out and purge. 
   BRIEF SUMMARY OF THE INVENTION 
   A high purity chemical delivery system is provided that comprises three manifolds, and that is connected to a high purity chemical container having a push gas inlet port and a high purity chemical delivery port. 
   The first manifold comprises a first low dead space connector connecting the first manifold to the high purity chemical delivery port; a second low dead space connector for connecting the first manifold to the second manifold; and a third low dead space connector for connecting the first manifold to the third manifold. The first manifold also comprises a first diaphragm valve having one side connected to the first low dead space connector and to a second diaphragm valve, and the other side connected to the second low dead space connector; and a second diaphragm valve having one side connected to the first diaphragm valve, and the other side connected to the third low dead space connector. 
   The second manifold comprises a fourth low dead space connector connecting the second manifold to the third manifold, and a fifth low dead space connector connecting the second manifold to the push gas inlet port. The second manifold also comprises a third diaphragm valve having one side connected to the second low dead space connector and to a fourth diaphragm valve, and the other side connected to a high purity chemical utilization point; and a fourth diaphragm valve having one side connected to the third diaphragm valve, and the other side connected to a fifth diaphragm valve and to a sixth diaphragm valve. The fifth diaphragm valve instead has one side connected to the fourth diaphragm valve, and the other side connected to a seventh diaphragm valve; the seventh diaphragm valve has one side connected to the fifth diaphragm valve and to the fourth low dead space connector, and the other side connected to a vacuum transducer; the sixth diaphragm valve has one side connected to the fourth diaphragm valve and to an eighth diaphragm valve, and the other side connected to a ninth diaphragm valve; the eight diaphragm valve has one side connected to the sixth diaphragm valve and to a tenth diaphragm valve, and the other side connected to a pressure transducer; the ninth diaphragm valve has one side connected to the fifth low dead space connector, and the other side connected to a source of push gas; and the tenth diaphragm valve has one side connected to the eighth diaphragm valve, and the other side connected to a source of purge gas. 
   The third manifold comprises an eleventh diaphragm valve having one side connected to the third low dead space connector, and the other side connected to a twelfth diaphragm valve, which instead has one side connected to the fourth means for connecting, and the other side connected to the eleventh diaphragm valve and to a thirteenth diaphragm valve. In turn, the thirteenth diaphragm valve has one side connected to the twelfth diaphragm valve, and the other side connected to an outer source of vent or of vacuum. 

   
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
     The drawings constitute a part of this specification and include exemplary embodiments of the invention, which may be embodied in various forms. It is to be understood that in some instances various aspects of the invention may be shown exaggerated or enlarged to facilitate an understanding of the invention. 
       FIG. 1  is a schematic view of a first embodiment of the invention. 
       FIG. 2  is a schematic view of a second embodiment of the invention. 
       FIG. 3  is a front view of the second embodiment of the invention. 
       FIG. 4  is a front view of an alternate embodiment of a manifold of the second embodiment of the invention. 
   

   The following reference numerals were employed in the Figures: 
   FIG.  1   
   
       
         10  High purity chemical delivery system (first embodiment) 
         12  Container 
         14  Push gas inlet port 
         16  High purity chemical delivery port 
         18  First manifold 
         20  Second manifold 
         22  Third manifold 
         24  First low dead space connector 
         26  Second low dead space connector 
         28  Third low dead space connector 
         30  First diaphragm valve 
         32  Second diaphragm valve 
         34  Fourth low dead space connector 
         36  Fifth low dead space connector 
         38  Third diaphragm valve 
         40  Fourth diaphragm valve 
         42  Fifth diaphragm valve 
         44  Sixth diaphragm valve 
         46  Seventh diaphragm valve 
         48  Eighth diaphragm valve 
         50  Ninth diaphragm valve 
         52  Tenth diaphragm valve 
         54  Eleventh diaphragm valve 
         56  Twelfth diaphragm valve 
         58  Thirteenth diaphragm valve 
     
  
   FIG.  2   
   
       
         60  High purity chemical delivery system (second embodiment) 
         62  Container 
         64  Push gas inlet port 
         66  High purity chemical delivery port 
         68  First manifold 
         70  Second manifold 
         72  Third manifold 
         74  Third diaphragm valve 
         76  Eleventh diaphragm valve 
         78  Fourteenth diaphragm valve 
         80  Fifteenth diaphragm valve 
         82  First diaphragm valve 
         84  Fourth diaphragm valve 
         86  Sixth low dead space connector 
         88  Second diaphragm valve  88   
         90  First low dead space connector 
         92  Sixteenth diaphragm valve 
         94  Seventeenth diaphragm valve 
         96  Ninth diaphragm valve 
         98  Seventh low dead space connector 
         100  Fifth low dead space connector 
         102  Fifth diaphragm valve 
         104  Sixth diaphragm valve 
         106  Seventh diaphragm valve 
         108  Eighth diaphragm valve 
         110  Tenth diaphragm valve 
         112  Twelfth diaphragm valve 
         114  Thirteenth diaphragm valve 
         116  Push gas inlet valve 
         118  High purity chemical delivery valve 
     
  
   FIG.  4   
   
       
         120  Alternative embodiment of first manifold 
         122  First diaphragm valve 
         124  Sixteenth diaphragm valve 
         126  First low dead space connector 
     
  
   DETAILED DESCRIPTION OF THE INVENTION 
   Detailed descriptions of embodiments of the invention are provided herein. It is to be understood, however, that the present invention may be embodied in various forms. Therefore, the specific details disclosed herein are not to be interpreted as limiting, but rather as a representative basis for teaching one skilled in the art how to employ the present invention in virtually any detailed system, structure, or manner. 
   Turning first to  FIG. 1 , there is shown a first embodiment of the invention, which is particularly suitable for use in a direct liquid injection process in semiconductor fabrication. A high purity chemical delivery system  10  is connected to a high purity chemical container  12  having a push gas inlet port  14  and a high purity chemical delivery port  16 . High purity chemical delivery system  10  comprises a first manifold  18 , a second manifold  20 , and a third manifold  22 . Each of the manifolds includes a plurality of diaphragm valves that regulate the flow of liquid or gas in the delivery system, and one or more low dead space connectors that attach each manifold to another manifold, to container  12 , or to other parts of the manufacturing plant. 
   First manifold  18  is connected to container  12  by means of a first low dead space connector  24  (preferably a VCR fitting); to second manifold  20  by means of a second low dead space connector  26  (preferably a low obstruction fitting such as Fujikin&#39;s UPG gasket fitting or Hy-Tech&#39;s Full Bore 002); and to third manifold  22  by means of a third low dead space connector  28 . First manifold  18  further comprises a first diaphragm valve  30  and a second diaphragm valve  32 , wherein first diaphragm valve  30  has one side (preferably the seat side) connected to second low dead space connector  26 , and the other side (preferably the diaphragm side) connected to both first low dead space connector  24  and second diaphragm valve  32 . In turn, second diaphragm valve  32  has one side (preferably the seat side) connected to first diaphragm valve  30 , and the other side (preferably the diaphragm side) connected to third low dead space connector  28 . 
   Second manifold  20  is instead connected to third manifold  22  by means of a fourth low dead space connector  34 , and to container  12  by means of a fifth low dead space connector  36  (preferably a VCR fitting). Second manifold  20  further comprises a plurality of diaphragm valves, including third diaphragm valve  38 , which has one side (preferably the diaphragm side) connected to a high purity chemical utilization point, for instance, in a semiconductor manufacturing plant, to a process tool for semiconductor fabrication or to a second high purity chemical container, and the other side (preferably the seat side) connected to a fourth diaphragm valve  40 . Fourth diaphragm valve  40  instead has one side (preferably the seat side) connected to third diaphragm valve  38 , and the other side (preferably the diaphragm side) connected to a fifth diaphragm valve  42  and to a sixth diaphragm valve  44 . 
   Further, fifth diaphragm valve  42  has one side (preferably the seat side) connected to fourth diaphragm valve  40 , and the other side (preferably the diaphragm side) connected to a seventh diaphragm valve  46 , which in turn has one side (preferably the diaphragm side) connected to fifth diaphragm valve  42  and to fourth low dead space connector  34 , and the other side connected to a vacuum transducer, such as a manometer. 
   Still further, sixth diaphragm valve  44  has one side (preferably the diaphragm side) connected to an eighth diaphragm valve  48 , and the other side (preferably the seat side) connected to a ninth diaphragm valve  50 . In turn, eight diaphragm side  48  has one side (preferably the diaphragm side) connected to sixth diaphragm valve  44  and to one side (preferably the diaphragm side) of a tenth diaphragm valve  52 , while the other side (preferably the seat side) of tenth diaphragm valve  52  is connected to a source of purge gas, such as nitrogen. Instead, ninth diaphragm valve  50  has one side (preferably the seat side) connected to sixth diaphragm valve  44  and to fifth low dead space connector  36 , and the other side (preferably the diaphragm side) connected to a source of push gas, such as helium. Optionally, the conduit connecting ninth diaphragm valve  50  to fifth low dead space connector  36  may be divided in two segments connected by a low dead space connector (preferably, a low obstruction fitting), in order to facilitate installation of second manifold  20 . 
   Third manifold  22  is connected to first manifold  18  by means of third low space connector  28 , and to second manifold  20  by means of fourth low dead space connector  34 . Third manifold  22  also comprises an eleventh diaphragm valve  54 , a twelfth diaphragm valve  56 , and a thirteenth diaphragm valve  58 . More specifically, eleventh diaphragm valve  54  has one side (preferably the seat side) connected to third low dead space connector  28  and the other side (preferably the diaphragm side) connected to twelfth diaphragm valve  56 . Instead, twelfth diaphragm valve  56  has one side (preferably the diaphragm side) connected to eleventh diaphragm valve  54  and to one side (preferably the seat side) of thirteenth diaphragm valve  58 , while the other side of thirteenth diaphragm valve  58  (preferably the diaphragm side) is connected to an outer source, such as a source of vent or a source of vacuum. 
   The above embodiment has been described as having the first, second, and third manifolds connected by low dead space connectors; however, other means of connection may be employed, for instance, the first, second, and third manifolds may be welded to each other, or no connectors may be present and the manifolds may be connected to each other by means of continuous conduits. 
   Turning now to  FIG. 2 , there is shown a second embodiment of the invention, which is also particularly suitable for use in a direct liquid injection process in semiconductor fabrication. A high purity chemical delivery system  60  is connected to a high purity chemical container  62  having a push gas inlet port  64  and a high purity chemical delivery port  66 . High purity chemical delivery system  60  comprises a first manifold  68 , a second manifold  70 , and a third manifold  72 , each of the manifolds comprising diaphragm valves to regulate the flow of liquid or gas, and low dead space connectors to attach each manifold to container  62 , to other manifolds, or to other parts of the manufacturing plant. 
   The structure of this second embodiment may be readily understood by reference to the first embodiment, and by highlighting the differences between the two embodiments. 
   By comparing second manifold  20  in  FIG. 1  to second manifold  70  in  FIG. 1 , it will be appreciated that second manifold  70  further comprises an additional flow connection between third diaphragm valve  74  and eleventh diaphragm valve  76 , the additional flow connection comprising a fourteenth diaphragm valve  78  and a fifteenth diaphragm valve  80 . More specifically, one side of third diaphragm valve  74  (preferably the seat side) is connected to first diaphragm valve  82  and to fourth diaphragm valve  84 , while the other side (preferably the diaphragm side) is connected to one side of fourteenth diaphragm valve  78 . In turn, fourteenth diaphragm valve  78  has one side (preferably the seat side) connected to third diaphragm valve  74  and to fifteenth diaphragm valve  80 , and the other side (preferably the diaphragm side) connected instead to a high purity chemical utilization point, for instance, in a semiconductor fabrication plant, to a process tool or to a second high purity chemical container. Finally, one side (preferably the seat side) of fifteenth diaphragm valve  80  is connected to fourteenth diaphragm valve  78 , and the other side (preferably the diaphragm side) is connected to eleventh diaphragm valve  76  in third manifold  72  by means of a sixth low dead space connector  86 . 
   Further, in the second embodiment, one side of first diaphragm valve  82  (preferably the diaphragm side) is connected not only to second diaphragm valve  88  and to first low dead space connector  90 , but also to one side of sixteenth diaphragm valve  92  (preferably the seat side), while the other side of sixteenth diaphragm valve  92  (preferably the diaphragm side) is connected to a seventeenth diaphragm valve  94 . In turn, seventeenth diaphragm valve  94  has one side (preferably the seat side) connected to sixteenth diaphragm valve  92 , and also to ninth diaphragm valve  96  through a seventh low dead space connector  98  (preferably a low obstruction fitting), while the other side of seventeenth diaphragm valve  94  (preferably the diaphragm side) is connected to fifth low dead space connector  100 . Sixteenth diaphragm valve  92  is preferably positioned closer to first diaphragm valve  82  than to seventeenth diaphragm valve  94 , in order to minimize the wet surface areas of the delivery system. 
   The second embodiment has been described as having the first, second, and third manifolds connected by low dead space connectors; however, other means of connection may be employed, for instance, the first, second, and third manifolds may be welded to each other, or no connectors may be present and the manifolds may be connected by means of continuous conduits. 
   One of the advantages of the high purity chemical delivery system according to the present invention is the reduction in purge cycle times compared to systems employed in the prior art. Following is one example of purge cycle described with reference to the second embodiment, using the appropriate reference numbers to identify each valve. 
   During operation: 
   Shut all valves. Open valves  96 ,  94 , open push gas inlet valve  116 , open high purity chemical delivery valve  118 , open valves  82 ,  74 , and  78 . Apply push gas at source of push gas to push gas to deliver high purity chemical from container  62  to utilization point. 
   During purge:
         a. Open valves  116 ,  94 ,  104 ,  102 ,  112 , and  114 . Shut all other valves. Apply vacuum at source of vacuum.   b. Open valves  96 ,  104 ,  84 ,  74 ,  82 , and  118 . Shut all other valves. Apply push gas at source of push gas.   c. Open valves  110 ,  104 ,  92 ,  88 ,  76 , and  114 . Shut all other valves. Apply purge gas at source of purge gas, and vent at source of vent.   d. Open valves  110 ,  84 ,  82 ,  88 ,  76 , and  114 . Shut all other valves. Apply purge gas at source of purge gas, and vent at source of vent.   e. Open valves  110 ,  84 ,  74 ,  80 , and  114 . Shut all other valves. Apply purge gas at source of purge gas, and vent at source of vent.   f. Apply vacuum to circuit open valves  104 ,  84 ,  102 ,  112 , and  114 .   g. Open valves  104 ,  84 ,  102 , and  106 . Shut all other valves. Measure vacuum level with vacuum transducer to measure presence of residual chemical. If chemical is present above predetermined levels, repeat cycle.   h. Open valves  110 ,  104 ,  94 ,  92 ,  88 ,  76 , and  114 . Shut all other valves. Apply purge gas at source of purge gas, and vent at source of vent, removing ambient gas after a new container is installed.   i. Open valves  110 ,  84 ,  82 ,  88 ,  76 , and  114 . Shut all other valves. Apply purge gas at source of purge gas, and vent at source of vent.   j. Open valves  110 ,  84 ,  74 ,  80 , and  114 . Shut all other valves. Apply purge gas at source of purge gas, and vent at source of vent.   k. Apply vacuum to circuit open valves  104 ,  84 ,  102 ,  112 , and  114 .   l. Open valves  106 ,  102 ,  84 ,  82 ,  92 ,  94 , and  104 . Shut all other valves. Check vacuum at vacuum transducer, monitoring possible leaks.   m. Open valves  114 ,  112 ,  106 ,  102 ,  84 ,  74 , and  80 . Shut all other valves. Apply vacuum at vacuum source, checking vacuum at vacuum transducer.       

   Turning now to  FIGS. 3–4 , there is shown in  FIG. 3  a front view of the second embodiment of the invention, and in  FIG. 4  a front view of an alternate embodiment  120  of first manifold  68 . More specifically, first diaphragm valve  82  in first manifold  68  is connected to first low dead space connector  90 , and is parallel and oriented in the same direction as sixteenth diaphragm valve  92 . Instead, in alternate embodiment  120 , first diaphragm valve  122  is parallel but rotated 90 degrees in relation to sixteenth diaphragm valve  124 , in order to achieve direct flow into the valve seat. Further, in alternate embodiment  120 , first connector  126  is connected not to first diaphragm valve  122 , but to sixteenth diaphragm valve  124 . 
   With further reference to  FIG. 2 , in a third embodiment of the invention there is no seventeenth diaphragm valve  94 , and the sixteenth diaphragm valve  92  has one side (preferably the seat side) connected to the first diaphragm valve  82 , and the other side (preferably the diaphragm side) connected to the fifth low dead space connector  100  and to the seventh low dead space connector  98 . 
   The above embodiments have been described as having manifold comprising a plurality of discrete valves. Some of the valves, however, may be grouped in multi-valve blocks. For instance, in the first embodiment illustrated in  FIG. 1 , valves  30  and  32  may be clustered in a two-valve block, and valves  38  and  40 , as well as  44  and  50 , may also be clustered in two-valve blocks. Likewise, valves  54 ,  56 , and  58  may be clustered in a three-valve block. 
   While the above described embodiments have been described with relation to a gas and vacuum purge process, the invention is equally adapted to a solvent purge process. Additionally, while the invention has been described in connection with the above described embodiment, it is not intended to limit the scope of the invention to the particular forms set forth, but on the contrary, it is intended to cover such alternatives, modifications, and equivalents as may be included within the scope of the invention.