Patent Publication Number: US-8539974-B2

Title: Forced-fluid switch

Description:
RELATED APPLICATION DATA 
     This application claims priority under 35 U.S.C. §119(e) to U.S. Provisional Application No. 61/323,594, filed Apr. 13, 2010, entitled “Forced-Fluid Switch”, the entire contents of which are incorporated herein by reference. 
    
    
     FIELD 
     The present disclosure relates to a forced-fluid switch to control forced fluid for a forced-fluid process chamber. The present disclosure also relates to a method of controlling the forced-fluid for a forced-fluid process chamber. 
     BACKGROUND 
     In the discussion of the background that follows, reference is made to certain structures and/or methods. However, the following references should not be construed as an admission that these structures and/or methods constitute prior art. Applicant expressly reserves the right to demonstrate that such structures and/or methods do not qualify as prior art. 
     Many products are produced using heat treatments in furnaces. Products undergo heat treatment for many reasons. For example, in semiconductor wafer fabrication the semiconductor wafers undergo thermal curing, and in steel manufacturing the steel undergoes an annealing process for hardening the steel. Sometimes the products reside within a furnace and fluid is forced through passageways in contact with the furnace to adjust the temperature of the furnace. In some cases, the fluid is forced through the furnace and the fluid comes in contact with the product. In still other cases, the fluid may be forced through an area between the furnace and a process chamber containing the product. A furnace may be called a forced-fluid process chamber particularly in semiconductor wafer production. 
     Often, in semiconductor production the temperature must be controlled very precisely and minor variations in the temperature can affect the yield or the percentage of wafers that may be sold. The temperature may need to be consistent throughout the forced-fluid process chamber, and the temperature may need to be raised or lowered in a specific amount of time. Often, the temperature of the product needs to be stabilized quickly so that the next step of the manufacturing process may begin and so that the heat treatment can be controlled precisely. 
     SUMMARY 
     A forced fluid switch is disclosed. The forced fluid switch includes a first plenum in communication with a first port; a second plenum in communication with a second port; a third plenum in switched communication with the first plenum and the second plenum and in communication with a third port; a fourth plenum in switched communication with the first plenum and the second plenum and in communication with a fourth port; and the forced fluid switch has at least a first forced fluid path and a second forced fluid path, and in the first forced fluid path, the third plenum is in communication with the first plenum and the fourth plenum is in communication with the second plenum, and in the second forced fluid path, the third plenum is in communication with the second plenum and the fourth plenum is in communication with the first plenum. 
     A method of switching forced fluid from a first forced fluid path to a second forced fluid path is disclosed. The may include simultaneously switching a first switch including a first spherical stopper and a second switch including a second spherical stopper by moving the first spherical stopper from blocking a first passage from a first plenum to a fourth plenum to blocking a second passage from the first plenum to a third plenum, and by moving the second spherical stopper from blocking a third passage from a second plenum to the third plenum to blocking a fourth passage from the second plenum to the fourth plenum. 
     A method of exchanging heat with a forced-fluid process chamber is disclosed. The method may include forcing a fluid flow having a direction through a fluid path around the forced-fluid process chamber using a blower having a force; reversing the direction of the fluid flow by simultaneously switching a first switch including a first spherical stopper and a second switch including a second spherical stopper by moving the first spherical stopper from blocking a first passage from a first plenum to a fourth plenum to blocking a second passage from the first plenum to a third plenum, and by moving the second spherical stopper from blocking a third passage from a second plenum to the third plenum to blocking a fourth passage from the second plenum to the fourth plenum; maintaining the force of the blower during the reversing; and wherein the first plenum may be in communication with the blower and the second plenum may be in communication with a vacuum configured to suck the forced fluid, and the third plenum and the fourth plenum are in communication with the fluid path around forced-fluid process chamber, and in the direction of the fluid flow the forced fluid travels from the first plenum to the third plenum and from the third plenum through the forced-fluid process chamber to the fourth plenum and from the fourth plenum to the second plenum, and in the reversed direction of the fluid flow path the forced fluid travels from the first plenum to the fourth plenum and from the fourth plenum through the forced-fluid process chamber to the third plenum and from the third plenum to the second plenum. 
     It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
       The following detailed description can be read in connection with the accompanying drawings in which like numerals designate like elements and in which: 
         FIG. 1A  is an example of a forced-fluid switch in a first state with a first forced-fluid path. 
         FIG. 1B  is an example of a forced-fluid switch in a second state with a second forced-fluid path. 
         FIG. 2  illustrates an example of a forced-fluid switch, the first valve assembly and the enclosing case. 
         FIG. 3  illustrates an example of a forced-fluid switch and the second valve assembly. 
         FIG. 4  illustrates an example of a forced fluid switch with a cooling system. 
         FIG. 5  illustrates an example of a forced fluid switch from a bottom view. 
         FIG. 6  illustrates a detailed example of a forced fluid switch. 
         FIG. 7  illustrates an example of four forced-fluid switches retrofitted into existing systems. 
         FIG. 8A  illustrates an example of cooling in one direction. 
         FIG. 8B  illustrates an example of bi-directional cooling. 
     
    
    
     DETAILED DESCRIPTION 
     Therefore there is a need in the art for a forced fluid switch and method of controlling the forced fluid switch. The forced fluid switch including a first plenum in communication with a first port; a second plenum in communication with a second port; a third plenum in switched communication with the first plenum and the second plenum and in communication with a third port; a fourth plenum in switched communication with the first plenum and the second plenum and in communication with a fourth port; and wherein the forced fluid switch has at least a first forced fluid path and a second forced fluid path, wherein in the first forced fluid path, the third plenum is in communication with the first plenum and the fourth plenum is in communication with the second plenum, and wherein in the second forced fluid path, the third plenum is in communication with the second plenum and the fourth plenum is in communication with the first plenum. 
       FIGS. 1A and 1B  illustrate an example of a forced-fluid switch  100 . The forced-fluid switch  100  includes a first plenum  10  with a first port  15 , a second plenum  20  with a second port  25 , a third plenum  30  with a third port  35 , a fourth plenum  40  with a fourth port  45 , a first valve assembly  50 , and a second valve assembly  60 . The fluid may be a gas such as air. In  FIG. 1A  cooling fins are illustrated in first plenum  10  and second plenum  20 . In  FIG. 1B  cooling fins are illustrated in only the first plenum  10 . 
     The first plenum  10  is formed by an enclosing case  70  (see  FIG. 2 ), a first divider  72 , a third divider  76 , and a fourth divider  78 . The first plenum  10  includes a first port  15 . The first port  15  is in communication with a forced-fluid process chamber  110 . The first plenum  10  is in switching communication with the third plenum  30  and the fourth plenum  40 . The first plenum  10  is in communication with the third plenum  30  as illustrated in  FIG. 1A  when the first valve assembly  50  and the second valve assembly  60  are in a first state. The first plenum  10  is in communication with the fourth plenum  40  as illustrated in  FIG. 1B  when the first valve  50  and the second valve assembly  60  are in a second state. The first plenum  10  may be in communication with both the third plenum  30  and the fourth plenum  40  during a transition period when the first valve assembly  50  and the second valve assembly  60  are switching between a first state as illustrated in  FIG. 1A  and a second state as illustrated in  FIG. 1B . 
     The second plenum  20  is formed by an enclosing case  70  (see  FIG. 2 ), a first divider  72 , a third divider  76 , and a fourth divider  78 . The second plenum  20  includes a second port  25 . The second port  25  is in communication with a forced-fluid process chamber  110 . The second plenum  20  is in switching communication with the third plenum  30  and the fourth plenum  40 . The second plenum  20  is in communication with the fourth plenum  40  as illustrated in  FIG. 1A  when the first valve assembly  50  and the second valve assembly  60  are in a first state. The second plenum  20  is in communication with the third plenum  30  as illustrated in  FIG. 1B  when the first valve  50  and the second valve assembly  60  are in a second state. The second plenum  20  may be in communication with both the fourth plenum  40  and the third plenum  30  during a transition period when the first valve assembly  50  and the second valve assembly  60  are switching between a first state as illustrated in  FIG. 1A  and a second state as illustrated in  FIG. 1B . 
     The third plenum  30  is formed by an enclosing case  70  (see  FIG. 2 ), a second divider  74 , and a third divider  76 . The third plenum  30  includes a third port  35 . The third port  35  is in communication with an active exhaust extractor  120 . The third plenum  30  is in switching communication with the first plenum  10  and the second plenum  20 . The third plenum  30  is in communication with the first plenum  10  as illustrated in  FIG. 1A  when the first valve assembly  50  and the second valve assembly  60  are in a first state. The third plenum  30  is in communication with the second plenum  20  as illustrated in  FIG. 1B  when the first valve  50  and the second valve assembly  60  are in a second state. The third plenum  30  may be in communication with both the first plenum  10  and the second plenum  20  during a transition period when the first valve assembly  50  and the second valve assembly  60  are switching between a first state as illustrated in  FIG. 1A  and a second state as illustrated in  FIG. 1B . 
     The fourth plenum  40  is formed by an enclosing case  70  (see  FIG. 2 ), a second divider  74 , and a fourth divider  78 . The fourth plenum  40  includes a fourth port  45 . The fourth port  45  is in communication with a blower unit  130 . The fourth plenum  40  is in switching communication with the first plenum  10  and the second plenum  20 . The fourth plenum  40  is in communication with the second plenum  20  as illustrated in  FIG. 1A  when the first valve assembly  50  and the second valve assembly  60  are in a first state. The fourth plenum  40  is in communication with the first plenum  10  as illustrated in  FIG. 1B  when the first valve  50  and the second valve assembly  60  are in a second state. The fourth plenum  40  may be in communication with both the first plenum  10  and the second plenum  20  during a transition period when the first valve assembly  50  and the second valve assembly  60  are switching between a first state as illustrated in  FIG. 1A  and a second state as illustrated in  FIG. 1B . 
     The enclosing case  70  (see  FIG. 2 ) as illustrated in  FIGS. 1A and 1B  includes four sides  71 , a bottom  73 , and a top  75 , and is in a box shape. In embodiments, the enclosing case  70  may be composed of several different parts or a single part. The enclosing case  70  could be a spherical shape or many different suitable three dimensional shapes. Additionally, the first divider  72 , the second divider  74 , the third divider  76 , and the fourth divider  78  (see  FIGS. 1A and 1B ) are substantially flat and straight. The first divider  72 , the second divider  74 , the third divider  76 , and/or the fourth divider  78  could be many different shapes and still perform the same function. In addition, the first divider  72 , the second divider  74 , the third divider  76 , and the fourth divider  78  could be incorporated into the other parts of the forced-fluid switch  100  such as the enclosing case  70 , and/or combined together into fewer dividers. 
       FIG. 1A  and  FIG. 1B  illustrate that the forced-fluid switch may be used to reverse the direction of forced fluid though a forced-fluid process chamber  110 . 
     As illustrated in  FIG. 1A , in operation, when the forced-fluid switch  100  is in a first state for a first forced-fluid path, fluid flows from the blower  130  through the fourth port  45  into the fourth plenum  40 , through the second valve assembly  60  into the second plenum  20 , out the second port  25  through the forced-fluid process chamber  110 , through the first port  15  into the first plenum  10 , through the first valve assembly  50  into the third plenum  30 , and through the third port  35  into a vacuum and an active exhaust extractor  120 . 
     As illustrated in  FIG. 1B , in operation, when the forced-fluid switch  100  is in a second state for a second forced-fluid path, fluid flows from the blower  130  through the fourth port  45  into the fourth plenum  40 , through the second valve assembly  60  into the first plenum  10 , out the first port  15  through the forced-fluid process chamber  110 , through the second port  25  into the second plenum  20 , through the first valve assembly  50  into the third plenum  40 , and through the third port  35  into a vacuum and an active exhaust extractor  120 . 
     The first port  15 , the second port  25 , the third port  35 , and the fourth port  45  may be in communication with different apparatuses than illustrated in the example of  FIG. 1 . For example, the third port  35  may be in communication with an input of the blower  130 . Additionally, since the forced-fluid switch may be sealed, the forced-fluid switch may be incorporated into systems requiring a recirculation (closed loop) or semi-recirculating cooling flow. For example, the forced-fluid switch  100  may be used when an inert gas must be used and recycled as the cooling fluid for a forced-fluid process chamber  110 . 
     The active exhaust extractor  120  may be powered by a venturi device. The active exhaust extractor  120  may be a passive exhaust. The blower may be powered by a centrifugal blower. 
       FIG. 2  illustrates an example of a forced-fluid switch, the first valve assembly and the enclosing case  70 . As illustrated in  FIG. 2 , the first valve assembly  50  includes a first conduit  52 , a second conduit  54 , a first spherical stopper  56 , a first connector  57 , a first shaft  58 , and a first rotary actuator  59 . For discussion purposes, the first valve assembly  50  is illustrated out of the forced-fluid switch  100 . The first conduit  52  connects the third plenum  30  with the first plenum  10 . The second conduit  54  connects the third plenum  30  with the second plenum  20 . The first spherical stopper  56  may be articulated between the first conduit  52  and the second conduit  54  by the first shaft  58 . A first connector  57  attaches the first spherical stopper  56  to the first shaft  58 . The spherical stopper  56  is rotationally attached to the first connector  57 . The first connector  57  is attached to the first shaft  58 . The first shaft  58  is connected to a first rotary actuator  59  that moves the first spherical stopper  56  from blocking the first conduit  52  to blocking the second conduit  54 . The attachment of the first spherical stopper  56  to the first shaft  58  permits the first spherical stopper  56  to have some adjustment room to fit snugly into the first conduit  52  and the second conduit  54 . The enclosing case  70  includes four sides  71 , a bottom  73 , and a top  75 . 
       FIG. 3  illustrates an example of a forced-fluid switch  100  and the second valve assembly. As illustrated in  FIG. 3 , the second valve assembly  60  includes a third conduit  62 , a fourth conduit  64 , a second spherical stopper  66 , a second connector  67 , a second shaft  68 , and a second rotary actuator  69 . For discussion purposes, the second valve assembly  60  is illustrated out of the forced-fluid switch  100 . The third conduit  62  connects the fourth plenum  40  with the first plenum  10 . The fourth conduit  64  connects the fourth plenum  40  with the second plenum  20 . The second spherical stopper  66  may be articulated between the third conduit  62  and the second conduit  64  by the second shaft  68 . A second connector  67  attaches the second spherical stopper  66  to the second shaft  68 . The second spherical stopper  66  is rotationally attached to the second connector  67 . The second connector  67  is attached to the second shaft  68 . The second shaft  68  is connected to a second rotary actuator  69  that moves the second spherical stopper  66  from blocking the third conduit  62  to blocking the fourth conduit  64 . The attachment of the second spherical stopper  66  to the second shaft  68  permits the second spherical stopper  66  to have some adjustment room to fit snugly into the third conduit  62  and the fourth conduit  64 . 
     In operation, in the embodiment discussed above, the first valve assembly  50  and the second valve assembly  60  are self-aligning due to the nature of the spherical stoppers coming in contact with the conduits. The forced fluid forces the spherical stopper into an aligned position to stop the flow of fluid as long as the shaft and actuator permit the spherical stopper to move into the conduit in reaction to the force of the fluid so as to seal the conduit. Additionally, in the embodiment discussed above, resistance to fluid is lessened by the spherical shape of the spherical stoppers during actuation due to the shape of the sphere. When a spherical stopper is stopping the flow of fluid into a conduit, a small motion of the actuator will allow some fluid to flow into the conduit and because of the spherical shape of the stopper the fluid will not create a large force opposing the motion of the spherical stopper to continue to open. This design enables the fluid flow to be reversed through an apparatus even in high fluid flow conditions without powering down the blower or the active exhaust extractor. This may be very important in some applications where maintaining a constant temperature is important. Additionally, this may improve cooling performance and shorten stabilization times which increases throughput and may shorten manufacturing time. Additionally, a spherical stopper has the advantage that when it expands and contracts due to the temperature changes it remains in a shape that will still fit within the conduits and seal the conduits. 
     In embodiments, the first valve assembly  50  and the second valve assembly  60  may be actuated by a single actuator. For example, the first valve assembly  50  and the second valve assembly  60  may be arranged 180 degrees apart. In embodiments, the rotary actuator may be a linear actuator with the motion converted by mechanical means to a rotary force. In embodiments, the valve openings are arranged to be substantially co-linear, and a linear actuator articulates a stopper between the two co-linear valve openings. 
     The first conduit  52 , the second conduit  54 , the third conduit  62 , and the fourth conduit  64  may be constructed from tubular valve seats. In embodiments, the first conduit  52 , the second conduit  54 , the third conduit  62 , and the fourth conduit  64  are approximately 50 millimeters (MM) to minimize the back pressure generated by fluid flows of approximately 100 standard cubic feet per minute (SCFM). 
       FIG. 4  illustrates an example of a forced fluid switch with a cooling system. The cooling system  90  includes a water pipe  92  and fins  94 . The fluid pipe  92  may be constructed of a metal such as copper or a hard plastic. The fluid pipe  92  holds a fluid that is circulated by a means such as a pump (not illustrated.) The fluid may be cooled by a means such as a compressor (not illustrated) or chiller (not illustrated) to transfer heat from the fins  94  and the forced-fluid switch  100  to the pipe  92  and the fluid that is circulated by the pipe  92 . The pipe  92  may be attached to a side  96  of the forced-fluid switch  100 . The fins  94  may be constructed of a metal such as aluminum or stainless steel. The fins  94  may be attached to a side  96  of the forced-fluid switch  100  opposite to the pipe  92 . The fins  94  may transfer heat from the forced-fluid in the forced-fluid switch  100  to the fins  94  and to the side  96 . The fins  94  may be positioned in the first plenum  10  and the second plenum  20 . The fins  94  may be positioned in different plenum(s) of the forced-fluid switch  100 . The fins  94  may provide the advantage of cooling the forced-fluid in the forced-fluid switch  100  when the forced fluid is returning from a heat source such as a forced-fluid process chamber  110  (Illustrated in  FIG. 1 ). By cooling the forced fluid when the fluid enters the forced-fluid switch  100  with the fins  94  the forced fluid may cool the forced fluid so that the forced fluid does not damage parts of the forced-fluid switch  100 . By cooling the forced fluid when it returns from a heat source, it may be possible to construct the forced-fluid switch  100  of less expensive materials. Additionally, the fins  94  may cool the forced-fluid before the forced fluid flows to a source of heat such as the forced-fluid process chamber  110  (illustrated in  FIG. 1 ). The forced-fluid switch  100  can then act as a cooler for the heat source such as the forced-fluid process chamber  110  (illustrated in  FIG. 1 ). The cooling system  90  may provide the advantage that by including the cooling system  90  within the forced-fluid switch  100  the forced-fluid switch  100  can switch the direction of the flow of fluid and provide a source of cooling. 
       FIG. 5  illustrates an example of a forced-fluid switch from a bottom view. The pipe  92  is attached to a side  96  of the forced-fluid switch  100  with a clamp  98 . The fins (not illustrated) are attached to the side  96  so that the fins project into the first plenum  10  and the second plenum  20  of the forced-fluid switch  100 . Heat flows from the forced fluid to the fins to the side  96  then to the pipe  92  then to the fluid in the pipe  92  to an another source such as a compressor. 
       FIG. 6  illustrates a detailed example of a forced-fluid switch. The forced-fluid switch  100  includes a base plate  201 , gaskets  203 , a sleeve  209 , a bearing-assembly  210 , a first rotary actuator mount  212 , a second rotary actuator mount (not illustrated), a first actuator  213 , a second actuator (not illustrated), a cover  216 , a solenoid valve  217 , and hex nuts  218 . The first actuator  213  controls the position of the first valve (not illustrated). And the second actuator (not illustrated) controls the position of the second valve (not illustrated). The solenoid valve  217  may control the first actuator  213  and the second actuator (not illustrated). The solenoid valve  217  may be in communication with a controller (not illustrated) that controls the operation of the forced-fluid switch  100 . 
       FIG. 7  illustrates an example of four forced-fluid switches retrofitted into existing systems. The retrofitted existing systems include four forced-fluid switches  100 A,  100 B,  100 C, and  100 D, a blower  130 , an active exhaust extractor  120 , a first fluid way  112  to a forced-fluid process chamber, a second fluid way  114  into a forced-fluid process chamber, a first port  15 , a second port  25 , a third port  35 , and a fourth port  45 . The first fluid way  112  and the second fluid way  114  are in communication with one another via a forced-fluid process chamber. Forced-fluid switch  100 A as illustrated is configured as in  FIG. 1A  in a first state for a first forced-fluid path. Forced-fluid switch  100 B as illustrated is configured as in  FIG. 1B  in a second state for a second forced-fluid path. The first port  15  is in communication with the first fluid way  112 . The second port  25  is in communication with the second fluid way  114 . The third port  35  is in communication with the active exhaust extractor  120 . The fourth port  45  is in communication with the blower  130 . Each of the first port  15 , the second port  25 , the third port  35 , and the fourth port  45  may be in communication via a fluid pathway that may be a duct constructed of metal or hard plastic or another suitable material. Each of the first port  15 , the second port  25 , the third port  35 , and the fourth port  45  may be arranged differently so as to be compatible with existing systems or so as to be compatible with the design of a new system. The active exhaust extractor  120  may be a blower that that powers a venturi device. 
     The materials used for the forced-fluid switch may be designed to be compatible with fluids such as fluids with elevated temperatures. 
       FIG. 8A  illustrates an example of cooling in one direction.  FIG. 8B  illustrates an example of bi-directional cooling.  FIGS. 8A and 8B  illustrate a reduction in stabilization time from 98 minutes to 63 minutes as a result of the bi-directional cooling enabled by embodiments described above. 
     Although described in connection with preferred embodiments thereof, it will be appreciated by those skilled in the art that additions, deletions, modifications, and substitutions not specifically described may be made without department from the spirit and scope of the invention as defined in the appended claims.