Abstract:
A modular fluid handling assembly includes a plurality of fluid handling units. Each fluid handling unit includes a fluid passage and associated port, a vacuum passage and associated port, a vacuum pressure source, and a containment seal. The fluid passage ports and vacuum passage ports of adjacent fluid handling units respectively communicate. The containment seal is disposed between adjacent fluid handling units and surrounds the communicating fluid passage ports and vacuum passage ports. The vacuum pressure source is in continuous communication with the vacuum passages of the fluid handling units, generates an urging force which aids in sealing adjacent fluid handling units together, and draws off any fluid that may leak from a fluid passage port. A sensor can be tapped into the vacuum line to sense whether any fluid has leaked from a fluid passage port.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to a modular fluid handling assembly for conducting or distributing one or more fluids, and the individual modular fluid handling units comprising the assembly. More particularly, the invention relates to a modular fluid handling assembly, and individual units, with double-containment sealing capability. The invention further relates to a modular fluid handling assembly, and individual units, which allow for continuous monitoring of, and drawing off of, fluid leakage. 
     2. Description of the Related Art 
     In the semiconductor manufacturing industry, many hazardous fluids are used and must be carefully handled to prevent damage to equipment and injury to both the environment and production employees. Examples of such fluids include toxic and corrosive gases such as SiH 4 , BCl 3 , and HCl. These fluids must be kept as pure as possible during all aspects of the handling and supply, since any contact of the flow stream with a contaminant may result in defects in the manufactured products. These defects are usually not detected until after the manufacturing operation has been completed. 
     During the manufacturing process, certain fluids must be distributed to various locations in precise amounts. To accomplish this, the industry has used gas sticks, which comprise a plurality of discrete blocks connected together, and on which a plurality of external devices may be mounted. FIGS. 6 a - 6   c  depict one such conventional block. 
     The conventional block  90  includes a fluid passage  91 , and associated ports  92 ,  92 ′, through which a process fluid flows. The block  90  also includes external device passages  93 ,  94  and associated ports  95 ,  95 ′,  96 ,  96 ′, for fluid communication with an external device  97 . When two or more blocks  90  are connected together, the process fluid flows through and among the blocks  90  and one or more external devices  97  by way of the internally bored passages  91 ,  93 ,  94  and associated ports  92 ,  92 ′,  95 ,  95 ′,  96 ,  96 ′. These discrete blocks  90  and external devices  97  require numerous junctions, which result in numerous opportunities for leakage. 
     To alleviate leakage between and among the discrete blocks  90  and external devices  97 , the industry has used metallic compression seals  98  at junctions between the individual passage ports  92 ,  92 ′,  95 ,  95 ′,  96 ,  96 ′. However, these individual seals  98  are still subject to leakage. Even extremely small amounts of leakage can result in personnel injury, equipment damage, or manufacturing defects. Typically, these leaks are detected only by detecting product degradation or by removing the entire gas stick from the system and performing a conventional leak test. 
     SUMMARY OF THE PRESENT INVENTION 
     It is therefore a principal object of the present invention to provide a modular fluid handling assembly for conducting or distributing one or more fluids, and the individual modular fluid handling units comprising the assembly, with double-containment sealing to prevent leakage or contamination of the fluid. 
     Another object of the present invention is to provide a modular fluid handling assembly, and the individual modular fluid handling units comprising the assembly, with a negative pressure source continuously connected to a region between adjacent units to provide an improved seal connection therebetween. 
     Still another object of the present invention is to provide a modular fluid handling assembly, and the individual modular fluid handling units comprising the assembly, with a negative pressure source continuously connected to a region between adjacent units to draw off any fluid that may leak from a fluid passage port. 
     Yet another object of the present invention is to provide a modular fluid handling assembly including a detector for detecting leakage of fluid. 
     In one aspect of the present invention, a modular fluid handling assembly includes a plurality of fluid handling units. Each fluid handling unit includes a fluid passage and associated port, a vacuum passage and associated ports, a vacuum pressure source, and a containment seal. The fluid passage ports and vacuum passage ports of adjacent fluid handling units respectively communicate. The vacuum pressure source is in communication with the vacuum passages of the fluid handling units. The containment seal is disposed between adjacent fluid handling units and surrounds the communicating fluid passage ports and vacuum passage ports. 
     In a further aspect of the present invention a modular fluid handling unit includes a fluid passage, a vacuum passage, and a containment seal. The fluid passage extends through the unit and includes two fluid passage ports. The vacuum passage extends through the unit and includes a vacuum passage port proximate each fluid passage port. A containment seal surrounds the vacuum passage ports and proximate fluid passage ports. 
     In yet a further aspect of the present invention a modular fluid handling assembly includes a plurality of fluid handling units. Each fluid handling unit includes at least one fluid passage and an associated fluid passage port. A fluid passage port of one fluid handling unit communicates with a fluid passage port of an adjacent fluid handling unit. A primary seal is included between fluid passage ports of adjacent fluid handling units, and a secondary seal surrounds the primary seal. A means for applying a negative pressure source to a region between adjacent fluid handling units and between the primary and secondary seals is also included. The negative pressure applying means generates a force urging adjacent fluid handling units together. 
     These and other objects, aspects, advantages and features of the present invention will become more apparent to those skilled in the art when the following detailed description is read in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the following detailed description, reference will be made to the attached drawings in which: 
     FIG. 1 is an exploded perspective view of a modular fluid handling assembly according to the present invention. 
     FIG. 2 a  is a perspective illustration of one embodiment of a modular fluid handling unit according to the present invention. 
     FIG. 2 b  is a top plan view of the modular fluid handling unit of FIG. 2 a.    
     FIGS. 2 c ,  2   d , and  2   e  are sectional views of the modular fluid handling unit of FIG. 2 a  along section lines  2   c — 2   c ,  2   d — 2   d , and  2   e — 2   e , respectively, of FIG. 2 b.    
     FIGS. 3 a - 3   e ,  4   a - 4   e , and  5   a - 5   e  illustrate alternative embodiments of modular fluid handling units according to the present invention. 
     FIG. 6 a  is a perspective illustration of a conventional discrete fluid handling block. 
     FIG. 6 b  is a top plan view of the conventional fluid handling block of FIG. 6 a.    
     FIG. 6 c  is a sectional view of the conventional fluid handling block along section line  6   c — 6   c  of FIG. 6 b.   
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1 depicts an exploded view of a modular fluid handling assembly  10  according to one aspect of the present invention. The assembly depicted is formed of a plurality of modular fluid handling units  30 A- 30 H and various external devices and connection units. The connection units can include fluid inlet connection units  11  and  12 , fluid outlet connection unit  13 , dual connection unit  16  or any other suitable connection. The external devices can include valves  14  and a mass flow controller  15 . These types of external devices are not limited, however, and any other devices used in fluid handling, including filters and pressure gauges, for example, can be used. Dual connection unit  16  includes an inlet connection  17  and a vacuum connection  18 . Vacuum connection  18  is connected to a vacuum pressure source  19 , with a sensor  20  preferably included between vacuum connection  18  and vacuum pressure source  19 . 
     The modular fluid handling system  10  will be further discussed below. However, referring now to FIGS. 2 a - 2   e , a more detailed description of an individual modular fluid handling unit will first be given. 
     A modular fluid handling unit  30  includes external device fluid passages  32  and  34 , inlet port  36 , external device connection ports  38  and  42 , and outlet port  44 , to provide fluid connection to a connection unit or an external device, generally designated by  40 . Ports  38  and  42  are preferably formed in a top face of unit  30 , whereas ports  36  and  44  are disposed in opposite side faces. Alternatively, or in addition to external device passages  32 ,  34 , the modular fluid handling unit  30  may include at least one fluid passage  46  that extends through the unit, with associated inlet  48  and outlet  52  ports on the opposing side faces. 
     A vacuum passage  54 , including inlet  56  and outlet  58  vacuum passage ports disposed in the opposing side faces, extends through the unit  30 . An additional vacuum passage port  62 , in fluid communication with a branch of vacuum passage  54 , is provided proximate fluid passage ports  38  and  42  in the top face. 
     A primary seal  64  is disposed at each fluid passage port to enhance fluid tight communication between adjacent fluid handling units or between a fluid handing unit and an attached external device or connection unit  40 . Seals  64  may comprise an O-ring manufactured of any suitable material for providing sealing, but in a preferred embodiment are metal compression seals. Each seal  64  sits in a recess in a face of fluid handling unit  30  or external device or connection unit  40 , with each recess surrounding a respective fluid port. When adjacent fluid handling units or a fluid handling unit and a connection unit are secured to one another, the primary seals  64  of corresponding ports mate and are compressed against one another to form the seal. 
     Containment seals are provided between each pair of contacting faces of adjacent fluid handling units  30  or between a fluid handling unit  30  and an external device or connector unit  40 . In this embodiment, one containment seal  66  is provided to surround vacuum passage port  56  and the proximate fluid passage inlet ports  36  and  48 . The containment seal  66  fits in a groove  68  formed in side face of fluid handling unit  30  to surround the vacuum passage port  56  and proximate fluid passage inlet ports  36  and  48 . The depth of groove  68  is less than the width of containment seal  66 , such that a portion of containment seal  66  protrudes beyond the side face of fluid handling unit  30 . An additional containment seal  72 , which fits in a groove  74  in the top face, surrounds external device connection ports  38  and  42  and associated vacuum passage port  62 . The containment seals  66 ,  72  may comprise O-rings manufactured of any material suitable for providing sealing. 
     The vacuum passage ports  56 ,  62  are associated with respective vacuum channels  76 ,  78 . Channel  76  is disposed in the side face within the region between the containment seal  66  and the fluid passage ports  36  and  48 , whereas channel  78  is disposed in the top face within the region between containment seal  72  and fluid passage ports  38 ,  42 . Each channel  76 ,  78  is formed as a contiguous recess in a face of fluid handling unit  30 . The shape of the channels depicted in the illustrations is a C-shape; however, the channel shape is not so limited. Rather, the size and shape of each channel  76 ,  78  is selected to maximize the channel surface area for a given fluid passage port configuration. Designing the channels  76 ,  78  this way allows communication of vacuum pressure between adjacent units even if the vacuum passage channels of adjacent fluid handling units are not collocated. That is, when two fluid handling units  30  are secured to one another, the vacuum channel formed in one of the adjoining faces can act as a vacuum passage between the vacuum ports that are not adjacent one another. When a C-shaped channel is used, the vacuum ports must be positioned at a radius from the center of the face equal to the radius at which the vacuum channel is formed. 
     Thus, fluid handling units of varying designs can be placed adjacent each other, as long as the fluid passage ports of adjacent fluid handling units are collocated. By not limiting the positions of the vacuum passages and ports in each fluid handling unit, the number of possible fluid passage configurations is increased. 
     By providing vacuum channels  76 ,  78  between adjacent fluid handling units  30  or between a fluid handling unit and an external device or connection unit  40 , the connection force between the units is increased. More particularly, the vacuum in a channel of a face of one unit acts on the face of the adjacent unit to urge the two faces together. By maximizing the surface area of the channels  76 ,  78 , the urging force, for a given vacuum pressure, between adjacent units will be maximized. 
     Maximizing the size of the channel also increases the ability to draw away any fluid that may leak from a fluid passage port surrounded by the channel. 
     Preferably, only one vacuum channel and one containment seal are provided between adjoining faces of adjacent fluid handling units  30  or between adjoining faces of fluid handling unit  30  and an external device or connection unit  40 . In order to maintain a standard, if the fluid handling units have ports in two side faces and the top face as shown in the embodiment of FIGS. 2 a - 2   e , then a vacuum channel and a groove for the containment seal are provided in the top face and in only one of the opposing side faces of each fluid handling unit. No vacuum channel or containment seal groove are provided in the other side face or the adjoining face of an external device or connection unit. 
     Fastening devices  80  are used to fasten adjacent fluid handling units  30  together, and to fasten any external device or connection unit  40  to a fluid handling unit  30 . The fastening devices  80  may be any type known to the ordinarily skilled artisan. In a preferred embodiment, the fluid handling units  30  and external devices or connection units  40  are bolted together via a plurality of through-holes  82 ,  84  formed in the units. In the preferred embodiment, the pattern and size of the external device through-holes  84  conform to SEMI 2871.1, a semiconductor manufacturing industry standard. 
     A modular fluid handling unit  30  can be manufactured in various sizes and geometric shapes. In the preferred embodiment, the units are blocks having generally cubical or rectangular shapes. The units can be manufactured from any material suitable for the fluid environment. In the preferred embodiment, the blocks are formed of stainless steel. 
     Various modifications to the fluid passages, vacuum passages, and associated ports can be made. Examples of various modifications are depicted in FIGS. 3 a - 3   e ,  4   a - 4   e , and  5   a - 5   e . The unit  30 ″ of the embodiment of FIGS. 3 a - 3   e  include three fluid passages, two of which branch into the top face such that two separate fluid flows can be in communication with external device or connection unit  40 . The fluid handling unit  30 ″ in the embodiment of FIGS. 4 a - 4   e  includes two fluid through passages and two passages that communicate with the top face. The fluid handling unit  30 ′″ in the embodiment of FIGS. 5 a - 5   e  includes two through passages that branch into separate ports on a top face. These variations and modifications are by no means inclusive. Indeed, a modular fluid handling unit according to the present invention may include only a single fluid passage, or any combination of fluid passages described herein. 
     Referring once again to FIG. 1, a modular fluid handling assembly  10  is formed by fastening together individual modular fluid handling units  30 A- 30 H and external devices and connection units  11 - 16 . The fluid handling units  30 A- 30 H are selected to ensure that fluid passage ports of adjacent units are collocated. However, as explained above, because of the vacuum passage channel design, adjacent vacuum passage ports need not be collocated. 
     Once the system components have been fastened together, the vacuum pressure source  19  is connected to the vacuum pressure source connection  18 , which communicates with vacuum passage  54  in unit  30 B. The vacuum pressure is distributed through the vacuum passages  54  in each of fluid handling units  30 A- 30 H to the vacuum channels between adjacent fluid handling units  30 A- 30 H, and between the fluid handling units  30 A- 30 H and the external devices and connection units  11 - 16 . As a result, an urging force is created therebetween which aids in sealing between the fluid handling units and the external devices and connection units together. Moreover, the vacuum pressure source will draw away any fluid that may leak from a fluid passage port. The sensor  20  can be placed in the line extending from the vacuum pressure source connection  18  to the vacuum pressure source  19 . Sensor  20  allows real-time, in-situ detection of any fluid that may leak from a fluid passage port. Sensor  20  can be any type known to the ordinarily skilled artisan for detecting a particular fluid flowing in the fluid passages. For example, sensor  20  can be a hydrogen mass spectrometer. 
     With the modular fluid handling units and the external devices and connection units connected in a desired configuration, processing fluid such as, for example, SiH 4 , BCl 3 , or HCl, can be controlled to reliably and safely flow through the fluid passages as designed. 
     It should be understood that the particular assembly depicted in FIG.  1  and described herein is only one illustrative example of the numerous assemblies which can be formed by an ordinarily skilled artisan practicing the present invention. 
     While preferred embodiments of the present invention have been illustrated in detail, it is apparent that modifications and adaptations of the preferred embodiments will occur to those skilled in the art. However, it will be expressly understood that such modifications and adaptations are within the spirit and scope of the present invention as set forth in the following claims.