Abstract:
A substrate carrier includes a carrier plate, a cover plate and a plurality of substrate support slots. The carrier plate has recesses for receiving substrates. A sidewall of each recess includes protrusions for engaging the OD of a substrate. The cover plate is rotatable-and has a cam on an undersurface. The cam is enagageable with a lateral slot in each of a plurality of substrate supports of the carrier plate. Rotating the cover plate causes the cam to move the substrate supports, one by one, so a substrate engaging end of the substrate support moves away from an associated substrate recess. A substrate is loaded into the recess, whereupon the cover plate is rotated further so the cam disengages from the lateral slot. The substrate supports are biased to engage the OD of the substrate to lock the substrate within the recess. Other embodiments are described and claimed.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    Embodiments of the present disclosure relate to the field of device manufacturing. More particularly, the present disclosure relates to an improved method and apparatus for holding multiple substrates during ion implantation or other substrate processing steps. 
         [0003]    2. Discussion of Related Art 
         [0004]    Attempts have been made to automate the handling and transfer of thin substrates during ion implantation, sputter coating and other processes both for preventing contamination, abrasion or damage to the substrates and for achieving a high throughput in terms of the number of substrates processed per unit time. Often, substrate cassettes are provided to hold a plurality of discs in vertically facing alignment. 
         [0005]    An automated substrate transfer system may be used to remove substrates from the cassette and to place the cassette in a container for transfer to a processing chamber where one or more deposition, implantation or other treatment processes can be performed. A problem with current substrate transfer containers is that they typically contact a portion of the substrate face. This is undesirable because substrate face damage can occur. 
         [0006]    Thus, there is a need for an improved system and method for carrying substrates from a cassette to a processing chamber. The system and method should provide consistent and reliable engagement of a substrate to minimize the chance for damage to occur to the substrate, either through dropping, through contact with of the substrate face, or through engagement with other substrates. 
       SUMMARY OF THE INVENTION 
       [0007]    The following presents a simplified summary in order to provide a basic understanding of some novel embodiments described herein. This summary is not an extensive overview, and it is not intended to identify key/critical elements or to delineate the scope thereof. Its sole purpose is to present some concepts in a simplified form as a prelude to the more detailed description that is presented later. 
         [0008]    A method and device are disclosed for holding multiple substrates during ion implantation or other procedure without touching either face of the substrate. A substrate carrier is disclosed for carrying a substrate having an outside diameter (OD), and first and second substrate faces. The substrate carrier comprises a carrier plate having a substrate recess, a cover plate recess and a substrate support slot. The substrate recess may include a protrusion on a recess sidewall, where the protrusion includes an inset portion. A cover plate is rotatably disposed in the cover plate recess, and a substrate support is slidably disposed in the substrate support slot. The substrate support has a substrate engaging end and an actuation end. A spring may be disposed between the actuation end of the substrate support and an end wall of the substrate support slot to bias the substrate support toward the recess. The substrate engaging end and the inset portion of the protrusion can be configured to engage the OD of the substrate to lock the substrate within the recess. 
         [0009]    A substrate carrier is disclosed for carrying a plurality of substrates having an outside diameter (OD). The substrate carrier comprises a carrier plate having a plurality of substrate recesses, each of the plurality of substrate recesses being configured to engage one of the plurality of substrates along the OD of the substrate. A cover plate may be rotatably engaged with the carrier plate. A plurality of substrate supports may be slidably disposed with respect to said carrier plate, each the plurality of substrate supports having a substrate engaging end that is movable into an associated one the plurality of substrate recesses to engage one of the plurality of substrates disposed therein. 
         [0010]    A method is disclosed for supporting a plurality of substrates in a carrier, each of the substrates having an outside diameter (OD). The method comprises: positioning a substrate adjacent to a carrier having a plurality of recesses, the recesses having at least two protrusions disposed on a sidewall thereof, each of the protrusions having an inset portion for engaging an OD of an associated one of said plurality of substrates; moving a substrate support in a first direction with respect to an associated one of the plurality of recesses; inserting a selected one of the plurality of substrates in the recess such that the OD of said selected substrate is positioned adjacent the at least two protrusions; and moving the substrate support in a second direction with respect to the associated one of the plurality of recesses to contact the OD of the selected substrate with a substrate engaging end of the substrate support. Contacting the OD of the selected substrate presses the substrate OD into engagement with the inset portions of the at least two protrusions to lock the selected substrate between the substrate engaging end and the inset portions. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    For a better understanding of the present disclosure, reference is made to the accompanying drawings, which are incorporated herein by reference and in which: 
           [0012]      FIGS. 1A and 1B  are perspective and cross-section views, respectively, of an exemplary substrate cassette; 
           [0013]      FIG. 2  is a schematic diagram of an exemplary substrate handling system; 
           [0014]      FIG. 3  is a perspective view of the disclosed substrate carrier engaged with a single substrate; 
           [0015]      FIG. 4  is a detail view of the device of  FIG. 3  showing engagement between the disclosed substrate carrier and a single substrate; 
           [0016]      FIG. 5  is a cross-section view of the disclosed substrate carrier of  FIG. 3  taken along line  4 - 4  of  FIG. 4 ; 
           [0017]      FIG. 6  is a cross-section view of the disclosed substrate carrier of  FIG. 3 , taken along line  5 - 5  of  FIG. 4 ; 
           [0018]      FIG. 7A  is a cross-section view of the interaction between the substrate carrier recess and an exemplary substrate, taken along line  7 A- 7 A of  FIG. 4 ; 
           [0019]      FIG. 7B  is a detail view showing the interaction between the movable substrate support and the substrate; 
           [0020]      FIG. 8  is a cross-section view of the disclosed substrate carrier of  FIG. 3 , taken along line  8 - 8  of  FIG. 3 ; 
           [0021]      FIG. 9  is a perspective view of an exemplary carrier plate portion of the disclosed substrate carrier; 
           [0022]      FIG. 10  is a reverse perspective view of an exemplary cover plate portion of the disclosed substrate carrier; and 
           [0023]      FIG. 11  is a perspective view of an exemplary substrate holder for use with the carrier of  FIG. 3 ; 
           [0024]      FIG. 12  is a cross-section view of the holder of  FIG. 10 , taken alone line  12 - 12  of  FIG. 10 ; 
           [0025]      FIGS. 13-15  are a series of cross-section views illustrating an exemplary operation of the substrate holder of  FIG. 11  loading a substrate onto the disclosed substrate carrier; and 
           [0026]      FIG. 16  is an exemplary logic flow implementing an embodiment of the disclosed method. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0027]      FIGS. 1A and 1B  show an exemplary substrate cassette  10  containing a plurality of substrates  24 . The cassette  10  may have front and back surfaces  16 ,  17 , first and second sidewalls  14 ,  15 , and pairs of left and right dividers  18   a,    18   b  that receive the substrates. The cassette  10  functions to protect the substrates  24  during transport and storage, but is not typically used to hold the substrates  24  during any of the variety of processing steps to which substrates of the kind are often subjected. For example, the substrates  24  may be subject to one or more ion implantation steps or one or more plasma doping steps. Thus, for such processing, the substrates may be transferred to another holding device, an example of which is often referred to as a front opening unified pod, or “FOUP.” The FOUP may be part of a substrate handling system that manipulates the individual substrates and subjects the substrates to one or more processing steps. 
         [0028]      FIG. 2  shows an exemplary substrate handling system  30  in which a plurality of FOUPs  31  each can hold a plurality of substrates. The substrates are transferred from the FOUPs  31  to a process chamber  32  via a buffer chamber  33 , load locks  34  and  35  and a wafer handler chamber  36 . Pod doors  37  interface the between the FOUPs  31  and the buffer chamber  33  so that substrates can pass between the FOUPs  31  and buffer chamber  33 . In buffer chamber  33 , an atmospheric robot  38  transports wafers along a track  39  to move wafers between the FOUPs  31  and load locks  34  and  35 . The buffer chamber  33  may be at or near atmospheric pressure, and provides a controlled, low particulate environment. The load locks  34  and  35  communicate with substrate handler chamber  36  through isolation valves  40  and  41 , respectively. The substrate handler chamber  36  may include one or more vacuum robots  42  and a substrate alignment station  43 . A substrate is transferred by one of the robots  42  from one of the load locks  34 ,  35  to substrate alignment station  43 . The substrate then is transferred to a process station  44  in process chamber  32  for processing, such as by ion implantation. The same process is reversed to transfer the substrate back to one of the FOUPs. 
         [0029]      FIG. 3  shows an exemplary carrier  50  for use in holding a plurality of substrates  24 . In one embodiment, the carrier  50  is loaded into a FOUP so that the substrates  24  may be subjected to one or more processing steps such as ion implantation, plasma doping, and the like. The carrier  50  can comprise a generally planar disk-shaped arrangement, which holds a plurality of substrates  24  having an ID, an OD and a face  24   a  that will be subject to one or more processing steps while being held in the carrier  50 . As will be described in greater detail later, the carrier  50  is arranged so that each substrate  24  is contacted only along the ID and/or OD such that contact with the substrate faces is avoided. As will be appreciated, this ensures that no damage to the substrate faces will occur during the carriage process. 
         [0030]    The carrier  50  may include a carrier plate  52 , a cover plate  54 , a plurality of movable substrate supports  56 , and a plurality of springs  58  (see  FIG. 8 ) associated with the substrate supports. The movable substrate supports  56  are retractable (against the bias of an associated spring  58 ) so that a substrate can be loaded into a carrier plate recess  60 . Once a substrate  24  is received in a recess  60 , the substrate support  56  is released so that it contacts the OD of the substrate  24 , locking the substrate in place in the recess  60 . As will be described in greater detail later, each substrate  24  is held in place using three points of contact along the substrate OD, the carrier plate  52  providing two points of contact and the substrate support  56  providing a third point of contact. 
         [0031]    In the illustrated embodiment, the recesses  60  are generally circular, having a bottom surface  61 , and a central protrusion  62  that fits within the ID of an associated substrate  24 . As will be described in greater detail later, the protrusion  62  does not support the substrate, but instead can be used as a centering device to ensure that the substrate it is held in a desired orientation with respect to the recess  60  as the substrate support  56  is being released. 
         [0032]      FIG. 4  shows the interaction between the carrier  50  and a single substrate  24 . As noted, the substrate is supported at three points, the first two points “A” and “B” being located on the perimeter of the carrier recess  60 , and the third point “C” being located on the movable substrate support  56 . 
         [0033]      FIG. 5  illustrates the profile of one of the recesses  60 , which may include a generally circular sidewall  64  having a diameter “d 1 ” that is greater than the OD of the substrate  24 . The sidewall  64  may include a lower beveled portion  66  disposed directly adjacent to the bottom surface  61  of the recess  60 . As can be seen, the lower beveled portion  66  may have a diameter “d 2 ” that is less than the OD of the substrate  24 . This arrangement ensures that the substrate lower face  24   b  will not contact the bottom surface  61  of the recess  60 , even if the substrate is incorrectly loaded into the carrier  50 , or in the event of a dropped substrate. The beveled portion  66  may form a bevel angle alpha a with respect to the bottom surface  61  of the recess  60 . In one embodiment, the bevel angle a is greater than a chamfer angle on the associated substrate  24  (where the substrate has a chamfered OD. Thus, where the chamfer angle on the substrate  24  is about  45  degrees on each edge, the bevel angle a is about  80  degrees. This arrangement can prevent the substrate face  24   b  from contacting the bottom surface  61  of the recess. 
         [0034]      FIG. 6  shows the interaction between the substrate OD and the carrier  50  at point of contact “B.” As can be seen, substrate  24  engages the carrier  50  at the substrate OD, which suspends the substrate lower face  24   b  above the bottom surface  61  of the recess  60  by a gap “g.” As previously noted, suspending the substrate above the recess bottom minimizes the chance that damage to the substrate faces  24   a,    24   b  can occur. In one embodiment, point of contact “B” is a protrusion  68  disposed on the side wall  64  of the recess  60 . The protrusion  68  extends inward, away from the sidewall  64 , and may include an inset portion  70  that receives the OD of the substrate  24  along an inset surface  72 . The inset surface  72  has upper and lower bevels  74 ,  76  that act to lock the substrate  24  in place along the inset surface  72 , ensuring that the substrate cannot slide up or down with respect to the carrier  50  once it is locked in place. It will be appreciated that the arrangement of point of contact “A” can be the same as that described in relation to point of contact “B.” 
         [0035]      FIGS. 7A and 7B  show the third point of contact “C” for the substrate  24  which is facilitated by the movable substrate support  56 . The movable substrate support  56  may include a support recess  80  disposed at a first end  82  of the support  56 . The support recess  80  may include first and second angled recess surfaces  80   a,    80   b.  The angling of the recess surfaces  80   a,    80   b  ensures that the substrate  24  is engaged about the OD and not on either the upper or lower face  24   a,    24   b.  As previously noted, this ensures that the substrate faces will not be damaged by the movable substrate support  56 . In the illustrated embodiment, the fork  84  of the support recess  80  is offset from the midpoint of the thickness “t” of the movable substrate support  56  such that the distance from the upper surface  56   a  of the support to the fork  84  (identified as “uft”) is less than the distance form the lower surface  56   b  of the support to the fork (identified as “lft”). This arrangement ensures that the desired gap “g” ( FIG. 7A ) will be maintained between the substrate  24  and the bottom surface  61  of the recess  60 . Although the OD of the substrate  24  is shown in the figures as being completely flat, it will be appreciated that the disclosed arrangement functions equally well with substrates having beveled or rounded ODs. That is, the support recess  80  of the movable substrate support  56  and the inset portions  70  of protrusions  68  will contact only the OD of such beveled or rounded edge substrates, and will not contact with the substrate faces  24   a,    24   b.    
         [0036]      FIG. 8  shows the actuation mechanism for one of the plurality of movable substrate supports  56 . In general, to load a substrate  24  onto the carrier  50 , the movable substrate support  56  is retracted (i.e., moved in the direction of arrow “A”) such that the first end  82  of the support is withdrawn from the associated carrier recess  60 , or at least moved far enough that the support recess  80  does not interfere with the substrate  24 . Once the substrate  24  is placed in the carrier recess  60 , the movable substrate support  56  is moved toward the substrate (i.e., in the direction of arrow “B”) until the support recess  80  engages the OD of the substrate. In one embodiment, the movable substrate support  56  is biased into engagement with the substrate  24  by spring  58 . The spring  58  can be a coil spring, or other appropriate biasing arrangement. As will be appreciated, the spring  58  provides a force appropriate for supporting the substrate  50  against the inset portions  70  of the protrusions  68  in the carrier sidewall  64 , thus keeping the substrate face  24   b  above the bottom surface  61  of the carrier recess  61 . 
         [0037]      FIG. 9  shows an exemplary carrier plate  52  with the cover plate  54  removed to show the interaction between the carrier plate and the movable support members  56 . The carrier plate  52  may include a plurality of slots  86  configured to slidingly receive respective movable support member  56 . The slots  86  are oriented radially and are aligned so that a first end  88  is disposed directly adjacent to a respective recess  60  and a second end  90  is disposed adjacent to a hub recess  92  of the carrier plate. The slots  86  may each have an end wall  94  (see  FIG. 8 ), and an associated spring  58  may be disposed against this end wall to bias the support member  56  toward the respective recess  60 . The height “h” (see  FIG. 8 ) of each slot  86  may be the same, or slightly greater than, the thickness “t” of the associated support member  56  such that when the support member is received within the slot and the cover plate  54  is fit to the carrier plate  52 , the support member is captured within the slot. 
         [0038]    The carrier plate  52  may include a circular cover plate recess  96  configured to receive the cover plate  54 , which is shown in greater detail in  FIG. 10 . The cover plate  54  may comprise a generally circular plate having upper and lower surfaces  98 ,  100 . The cover plate  54  and the cover plate recess  96  may be sized and configured so that the upper surface  98  of the cover plate is flush with an upper surface  102  of the carrier plate  52  when the carrier  50  is fully assembled. 
         [0039]    The lower surface  100  of the cover plate  52  may include a circumferential cam ring  104  that is received within a cam recess  106  in the carrier plate  52 . The cam ring  104  and cam recess  106  are sized and configured so that the cam ring  104  can slide within the cam recess  106  as the cover plate  52  is rotated with respect to the carrier plate  52 . The cam ring  104  may have a discrete radially inwardly projecting cam  108  disposed in a discrete location on the cam ring  104 . The cam  108  may project radially inward by a distance “ct.” Referring again to  FIG. 8 , the cam  108  may be configured to interact with an actuation recess  110  formed in the associated movable support member  56 . The actuation recess  110  may be a laterally oriented notch formed in the movable support member such that as the cover plate  54  is rotated (along with the cam ring  104  and cam  106 ), the cam  106  engages a side surface  112  of the support member and forces it radially inwardly along the slot  86  (in the direction of arrow “A”) against the bias of associated spring  58 . As will be understood, this causes the support member  56  to retract from the associated recess  60 , which clears the recess to receive a substrate  24 . Once the substrate  24  has been placed within the recess, the cover plate  54  can be rotated so that cam  106  rotates out of engagement with the side surface  112  of the support member actuation recess  110 . This, in turn, enables the spring  58  to move the support member  56  radially outwardly (in the direction of arrow “B”) so that the support recess  80  of the support member  56  engages the OD of the substrate  24 , locking the substrate within the recess  60 . The cam  106  can “actuate” each movable support member  56  in sequence, thus enabling the carrier  50  to be loaded with a plurality of substrates in a serial manner. 
         [0040]    The cover plate  54  can have a hub portion  114  that is received within hub recess  92  of the carrier plate  52 . A fastener (not shown) can be used to secure the two together in a manner that fixes them axially together, but which enables them to rotate freely with respect to each other. A spanner or other tool may be used to engage the cover plate  54  in a known manner to enable selective rotation of the cover plate  54  with respect to the carrier plate  52  so that one or more substrates  24  can be loaded into the carrier  50 . 
         [0041]    It will be appreciated that the cover plate  54  can alternatively be provided with a plurality of cams  106  so that all of the support members  56  can be retracted and released simultaneously. This would be useful for applications in which the carrier  50  is automatically loaded with a plurality of substrates at once. 
         [0042]    Referring now to  FIGS. 11 and 12 , an exemplary holder  120  is shown for use in engaging a substrate  24  with the carrier  50  prior to processing. The holder  120  may also be used to remove one or more substrates from the carrier subsequent to processing. As will be explained, the carrier  50  and holder  120  may include complementary features that enable the holder  120  to precisely align with the carrier  50  to facilitate a desired handoff of a substrate  24  between the two. The holder  120  may engage the substrate on the ID so that positive engagement of the substrate is ensured, while contact with the substrate faces  24   a,  b is avoided. Thus, the holder  120  may include a plurality of substrate supports  122  positioned about an alignment shaft  124 . The substrate supports  122  and alignment shaft  124  can be inserted through the ID of the substrate  24  in a retracted configuration (shown in  FIG. 12 ), and then adjusted to an expanded configuration in which the supports  122  engage the ID of the substrate  24  (shown in  FIG. 11 ). Distal portions  126  of the substrate supports  122  may have a cup-shape so that they can positively retain the ID of the substrate  24  when the holder is in the expanded configuration. The holder  120  can be adjusted between the retracted and expanded configurations manually or automatically. An example of the disclosed holder  120  is disclosed in related U.S. patent application Ser. No. ______, filed ______ (Attorney docket number 2011-057), the entirety of which is incorporated herein by reference. 
         [0043]    The holder  120  and carrier  50  may have complementary features to enable the holder  120  to align precisely with the carrier  50  and the substrate  24 . These complementary features ensure a smooth handoff of the substrate  24  between the two, minimizing the chance for damage to the substrate. Referring now to  FIG. 13 , the carrier  50  may include an alignment recess  128  disposed within the protrusion  62 . The alignment recess  128  may be a cylindrical recess configured to receive a nose portion  130  of the alignment shaft  124  of the holder  120  (see  FIGS. 5 and 7A ). In addition, a top surface  132  of the protrusion  62  may engage a shoulder  134  of the nose portion  130 . These features enable the holder  120  to positively engage the carrier  50  to ensure proper repeatable axial and radial alignment of the holder  120  and the carrier  50  to facilitate transfer of the substrate  24  therebetween. 
         [0044]    In operation, to transfer a substrate to the carrier, the movable substrate support  56  of a targeted recess  60  may be retracted by rotating the cover plate  54  in the previously described manner. The holder  120  (and attached substrate  24 ) may then be positioned over the targeted recess  60  such that the nose portion  130  of the holder  120  is aligned with the associated protrusion  62  (see  FIG. 13 ). The holder  120  may then be moved in the direction of arrow “C” until the nose portion  130  is inserted in the alignment recess  128  of the protrusion until the shoulder  134  contacts the top surface of the protrusion  132  (see  FIG. 14 ). At this point, the substrate  24  is held at a desired level above the bottom surface  61  of the recess  60  by the substrate supports  122 . The cover plate  54  may then be rotated until the cam  108  disengages from the movable substrate support  56 , enabling the spring  58  to move the support recess  80  of the movable substrate support  56  in the direction of arrow “D” (see  FIG. 15 ) so that it engages the OD of the substrate  24 . As previously noted, the movable substrate support presses the substrate  24  into engagement with the inset portions  70  of protrusions  68 , locking the substrate to the carrier  50 . The holder  120  may then be configured to the retracted position so that the substrate supports  122  disengage from the ID of the substrate  24 . The holder may then be removed. Though the reverse process will not be described in detail, it will be appreciated that the substrate  24  may be removed from the carrier  50  according to a reverse sequence of the previously described steps. 
         [0045]    The carrier  50  and its components can be constructed from any of a variety of materials, including graphite, metal, polymer and combinations thereof. Because the carrier  50  can be subject to the ion beam associated with implant processes, it may be desirable to provide a metal free carrier. The springs  58  may be metal, but these pieces will not be subject to the ion beam because they are disposed under the cover plate  54  in use. In some embodiments, a non-marring material rated to the flammability standards of UL 94-V0 may be used. In one exemplary embodiment, the carrier plate  52 , cover plate  54  and movable substrate supports  56  are constructed of polyetheretherketone (PEEK). 
         [0046]    An exemplary logic flow will now be described in relation to  FIG. 16 . At step  200 , a substrate  24  having an OD and an ID is positioned adjacent to a carrier  50  having a plurality of recesses  60 , the recesses having at least two protrusions  68  disposed on a sidewall thereof, each protrusion having an inset portion  72 . At step  210 , a movable substrate support  56  is moved in a first direction to enable insertion of the substrate in the recess. At step  220 , the OD of the substrate is positioned laterally adjacent to the inset portions. At step  230 , the movable substrate support is moved in a second direction opposite to the first direction to contact the OD of the substrate. At step  240 , the movable substrate support presses the substrate OD into engagement with the inset portions  72 . At step  250 , a determination is made whether a desired number of substrates has been installed in the carrier  50 . If the answer is yes, then at step  260  the method ends. If the answer is no, then the process returns to step  200 . 
         [0047]    Some embodiments of the disclosed device may be implemented, for example, using a storage medium, a computer-readable medium or an article of manufacture which may store an instruction or a set of instructions that, if executed by a machine, may cause the machine to perform a method and/or operations in accordance with embodiments of the disclosure. Such a machine may include, for example, any suitable processing platform, computing platform, computing device, processing device, computing system, processing system, computer, processor, or the like, and may be implemented using any suitable combination of hardware and/or software. The computer-readable medium or article may include, for example, any suitable type of memory unit, memory device, memory article, memory medium, storage device, storage article, storage medium and/or storage unit, for example, memory (including non-transitory memory), removable or non-removable media, erasable or non-erasable media, writeable or re-writeable media, digital or analog media, hard disk, floppy disk, Compact Disk Read Only Memory (CD-ROM), Compact Disk Recordable (CD-R), Compact Disk Rewriteable (CD-RW), optical disk, magnetic media, magneto-optical media, removable memory cards or disks, various types of Digital Versatile Disk (DVD), a tape, a cassette, or the like. The instructions may include any suitable type of code, such as source code, compiled code, interpreted code, executable code, static code, dynamic code, encrypted code, and the like, implemented using any suitable high-level, low-level, object-oriented, visual, compiled and/or interpreted programming language. 
         [0048]    The present disclosure is not to be limited in scope by the specific embodiments described herein. Indeed, other various embodiments of and modifications to the present disclosure, in addition to those described herein, will be apparent to those of ordinary skill in the art from the foregoing description and accompanying drawings. Thus, such other embodiments and modifications are intended to fall within the scope of the present disclosure. Furthermore, although the present disclosure has been described herein in the context of a particular implementation in a particular environment for a particular purpose, those of ordinary skill in the art will recognize that its usefulness is not limited thereto and that the present disclosure may be beneficially implemented in any number of environments for any number of purposes. Accordingly, the claims set forth below should be construed in view of the full breadth and spirit of the present disclosure as described herein.