Abstract:
The present invention relates to apparatuses and methods to store and transfer objects, and more particularly to workpiece stocker configurations such as stocker for semiconductor wafers, reticles or carrier boxes.

Description:
FIELD OF THE INVENTION 
     The present invention relates to semiconductor equipment, and more particularly, to equipment and method to improve fabrication facility processing. 
     BACKGROUND 
     Stockers generally are installed within a semiconductor facility for temporarily storing workpieces, such as wafers, flat panel displays, LCD, photolithography reticles, or masks. 
     In the process of manufacturing semiconductor devices, LCD panels, and others, there are hundreds of processing equipments and thus hundreds of manufacturing steps. It is very difficult for the flow of the wafers, flat panels, or LCDs (hereafter workpiece) to be uniform from step to step, from tool to tool. Despite the best planners, there is always the unexpected scenario, such as a tool down, an emergency lot coming through, a periodic maintenance lasting longer than planned, thus there are various accumulations of the workpieces at certain steps for certain tools. The accumulated workpieces will need to be stored in a storage stocker, waiting to be processed. 
     Further, photolithography process is a critical process in the semiconductor fabrication facility, involving a large number of photolithography masks or reticles (hereinafter reticle). The reticles thus are typically stored in a storage stocker, and being retrieved when needed into the lithography exposure equipment. 
     The storage of workpieces and reticles (hereafter articles) is much more complicated due to the requirement of cleanliness. Damages to the articles can be physical damages in the form of particles, or chemical damages, in the form of interactions. With the critical dimension of the semiconductor device processing surpassing 0.1 micron, particles of 0.1 micron size, and reactive species will need to be prevented from approaching the articles. The storage areas typically would need to be even cleaner than the processing facility, to ensure less cleaning between processing. 
     Thus the stocker storage areas is typically designed to be sealed off from the outside environment, preferably with constant purging, and even with inert gas flow to prevent possible chemical reactions. Access to the storage areas is load-locked, to ensure isolation between the clean storage environment and the outside environment. 
     In a typical bare stocker system, a robot is typically used to remove the workpieces from the carrier boxes, and then loaded into a storage chamber, where the workpieces are stored without the original carrier boxes. For box stocker system, the workpieces are stored together with the carrier boxes, without the need for removing them out of the carrier boxes. 
     The carrier box is a protective container to minimize the substrate exposure to the environment outside of the processing machines and protect the substrate against particulate contamination. The carrier boxes are handled by an operator or by an automatic material handling system such as automatically guided or overhead transport vehicles that travel on predetermined routes, either on the ground or suspended on ceiling tracks. For semiconductor wafers, the carrier boxes are normally cassettes pods, such as SMIF (standard machine interface) or FOUP (front opening unified pod), which are handled by an operator at the tools equipment front end module (EFEM) or automatically picked up and placed in the automatic transport system. 
     One type of conventional transport system is an overhead transport (OHT) system, which comprises an OHT vehicle, which runs freely on a rail mounted on a ceiling. The OHT vehicle carries a cassette pod between facility equipment, such as processing systems and stockers. The OHT vehicle can load or unload a cassette pod onto a load port of the equipment, for example a MLP (Mobile Launch Platform) or an EFEM. From there, the cassette pod or the wafers can be transferred from or to the inside of the equipment. 
     SUMMARY 
     The present invention relates to buffer stations, serving as an add-on storage for an equipment, such as for a workpiece stocker. For example, the present buffer add-on storage can be used to store workpiece containers for a bare workpiece stocker. 
     In some embodiments, the present invention discloses systems and methods comprising a buffer storage assembly that can be added to an existing equipment to serve as an external storage. The buffer storage assembly comprises a storage chamber and a robot system interfacing with the storage chamber. The robot system can further access the loadlock stations (e.g., loading or unloading stations), or any intermediate station (such as a transfer station or an exchange station) of the equipment, to transfer objects between the storage chamber and a station of the equipment. For example, the buffer storage assembly can be installed adjacent to the equipment, at a side of the equipment and near the loadlock station of the equipment. The robot arm can be configured to reach into the loadlock station, to pick up a container from the loadlock station to bring to the storage chamber, or to place a container to the loadlock station taken from the storage chamber. 
     In some embodiments, the present invention discloses a buffer storage assembly to be coupled to a bare workpiece stocker, for example, to store and to supply empty containers to the bare workpiece stocker. The buffer storage assembly can also be used to store containers having workpieces stored therein. 
     In some embodiments, the buffer storage assembly can be used to store containers having workpieces stored within. The whole assembly of bare workpiece stocker and the buffer storage assembly can have the added functionality of bare workpiece storage and workpieces storage within containers, in addition to empty container storage capability. 
     In some embodiments, the present invention discloses a combination workpiece stocker comprising a bare workpiece stocker coupled to a buffer storage assembly. The buffer storage assembly can be separated from the bare workpiece stocker, and coupled only at the container transfer level. Alternatively, the buffer storage assembly can be fully integrated to the bare workpiece stocker, forming a complete system having multiple capabilities. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1A-1C  illustrate an exemplary configuration of a workpiece container add-on storage for a bare workpiece stocker. 
         FIGS. 2A-2C  illustrate details of an exemplary buffer add-on storage assembly according to some embodiments of the present invention. 
         FIG. 3  illustrates a perspective view of an exemplary buffer add-on storage assembly according to some embodiments of the present invention. 
         FIGS. 4A-4B  illustrate exemplary buffer add-on storage assemblies according to some embodiments of the present invention. 
         FIGS. 5A-5B  illustrate exemplary configurations of buffer storage according to some embodiments of the present invention. 
         FIGS. 6A-6B  illustrate exemplary configurations for x-y movement mechanism according to some embodiments of the present invention. 
         FIGS. 7A-7C  illustrate exemplary sequences of end handle movements according to some embodiments of the present invention. 
         FIGS. 8A-8B  illustrate an exemplary container and exemplary movements of an end handle according to some embodiments of the present invention. 
         FIGS. 9A-9D  illustrate an exemplary sequence of container transfer to a storage location according to some embodiments of the present invention. 
         FIGS. 10A-10D  illustrate an exemplary movement sequence of robot having movable prongs according to some embodiments of the present invention. 
         FIGS. 11A-11E  illustrate an exemplary sequence of movable prongs for container transfer to a storage location according to some embodiments of the present invention. 
         FIGS. 12A-12C  illustrate an exemplary movement sequence of robot having gripper arms according to some embodiments of the present invention. 
         FIGS. 13A-13I  illustrate an exemplary sequence of movable gripper arms for container transfer to a storage location according to some embodiments of the present invention. 
         FIGS. 14A-14C  illustrate an exemplary end handle rotatably connecting to a robot arm according to some embodiments of the present invention. 
         FIGS. 15A-15E  illustrate an exemplary sequence of rotatable end handle for container transfer according to some embodiments of the present invention. 
         FIGS. 16A-16E  illustrate another exemplary sequence of rotatable end handle for container transfer according to some embodiments of the present invention. 
         FIGS. 17A-17D  illustrate exemplary configurations of a robot arm according to some embodiments of the present invention. 
         FIGS. 18A-18D  illustrate exemplary configurations of a robot arm with rotatable end handle according to some embodiments of the present invention. 
         FIGS. 19A-19D  illustrate exemplary configurations of folded arms with different end handles according to some embodiments of the present invention. 
         FIGS. 20A-20C  illustrate an exemplary robot arm with bended end handle according to some embodiments of the present invention. 
         FIGS. 21A-21D  illustrate exemplary access sequences of robot arms according to some embodiments of the present invention. 
         FIG. 22  illustrates an integrated stocker having a storage chamber  226  for bare workpiece storage, and storage chamber  225  for container storage, and portion  220  for workpiece and container handling. 
         FIG. 23  illustrates an exemplary flowchart for assembling a buffer storage assembly with a workpiece stocker according to some embodiments of the present invention. 
         FIGS. 24A-24C  illustrate exemplary flowcharts for operating a bare workpiece stocker according to some embodiments of the present invention. 
         FIGS. 25A-25B  illustrate exemplary flowcharts for utilizing the buffer assembly as loading or unloading buffer storage according to some embodiments of the present invention. 
         FIGS. 26A-26B  illustrate an exemplary controller system according to some embodiments of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The present invention relates to buffer stations, serving as an add-on storage for an equipment, such as for a workpiece stocker. In some embodiments, the present invention discloses systems and methods for a buffer storage assembly that can be added to an existing equipment to serve as an external storage. The buffer storage assembly comprises a storage chamber and a robot system interfacing with the storage chamber. The robot system can further access the loadlock stations (e.g., loading or unloading stations), or any intermediate station (such as a transfer station or an exchange station) of the equipment, to transfer objects between the storage chamber and a station of the equipment. For example, the buffer storage assembly can be installed adjacent to the equipment, at a side of the equipment and near the loadlock station of the equipment. The robot arm can be configured to reach into the loadlock station, to pick up a container from the loadlock station to bring to the storage chamber, or to place a container to the loadlock station taken from the storage chamber. 
     In some embodiments, the present buffer add-on storage can be used to store workpiece containers for a bare workpiece stocker. In bare workpiece stockers, the workpieces are removed from the containers to be stored bare in the stocker storage. The containers are located elsewhere, for example, re-used for other workpieces, or re-cleaned to return to storage. Thus when workpieces are needed from the bare stocker, a new container must be supplied. The present buffer add-on storage offers a means to store and supply containers, without a need to go search for an empty container. 
       FIGS. 1A-1C  illustrate an exemplary configuration of a workpiece container add-on storage for a bare workpiece stocker. The description of the present specification describes a workpiece container add-on storage for a bare workpiece stocker, but the present invention is not so limited, and can be used as an add-on storage assembly for any system, such as an external workpiece add-on storage for a workpiece stocker, or a workpiece add-on storage for a processing equipment. 
     In  FIG. 1A , a workpiece container add-on storage  11  is coupled to a bare workpiece stocker  12  having loading stations  13 . The term loading station is used in the context of the present invention as a station supporting a workpiece container, for example, a manual I/O station (e.g., station for loading to and unloading workpiece containers from the workpiece stocker  12  by an operator), an automatic I/O station (e.g., station for loading to and unloading workpiece containers from the workpiece stocker  12  by an automatic overhead transport system), or an intermediate or an interface station within the workpiece stocker  12 , serving to support a workpiece container as a transitioning station between the I/O station and the workpiece stocker system. For example, a container can be loaded to the I/O station (manual or automatic), and then transferred to an intermediate station, where the container is open for a robot to access the workpiece within. 
     In some embodiments, the bare workpiece stocker  12  is a stand alone workpiece stocker, capable of independent operation, with manual or automatic I/O stations for interfacing with other equipment in a fabrication facility. The bare workpiece stocker accepts containers having workpieces stored within, stores only the bare workpieces in its bare workpiece storage chamber, and ignores the workpiece containers. The workpiece container add-on storage  11  can be affixed to a side of the workpiece stocker, acting as an external storage for the workpiece stocker. The coupling between the workpiece container add-on  11  and the workpiece stocker  12  preferably comprises mating a robot arm of the container add-on storage  11  with the loading stations  13  of the workpiece stocker  12 , so that the container add-on storage  11  can access the containers in the loading stations  13 , for example, to pick up a container in the loading station  13  to store in a storage chamber of the container add-on assembly  11 , or to place a container to the loading station  13  from a storage chamber of the container add-on assembly  11 . 
     In an exemplary process flow, a container is bought to the workpiece stocker  12 , and the workpieces within the container are removed and stored in the workpiece stocker  12 . The robot of the container add-on storage then picks up the container (either completely empty or partially empty) and stores it in the container storage chamber of the container add-on storage  11 . In some embodiments, the robot can pick up the container with all the workpieces within, before the workpiece stocker accessing the workpieces, and stores the full container in its container storage chamber. For example, in this capacity, the container add-on storage  11  can serve as an input buffer station for the workpiece stocker, allowing the workpiece stocker to accept multiple containers in a very short time, and slowly retrieving the workpieces to the bare storage chamber. 
     For example, after receiving a number of full containers and storing in the container storage, the robot can retrieve the full containers, one at a time, back to the loading station  13  and allow the workpiece stocker to retrieve the workpieces within the container to be stored in the bare storage chamber. The empty container is then picked up by the robot, and re-stored in the container storage chamber. Another full container is then transferred from the container storage to the loading station. The process continues until all the workpieces in the number of full containers are transferred to the bare workpiece storage chamber, and the empty containers are stored in the container storage chamber. 
     Alternatively, the container storage chamber can served as an output buffer for the workpiece stocker. For example, a number of workpieces can be transferred to a number of containers and stored in the container storage chamber, ahead of being needed. For example, a controller can decide the workpieces to be needed in the next 6, 8, 10 or 24 hours, and then assemble the workpieces within the appropriate containers, and store the full containers in the container storage chamber. When needed, the full containers are ready to be transferred, without waiting for the assembling of the workpieces to the containers. 
     Further, with the container storage add-on  11  storing empty container, automatic assembling or disassembling of workpieces to workpiece containers can be performed, allowing faster throughput. For example, automatic assembling or dissembling of workpieces from workpiece containers can be performed with one operation (e.g., bringing a full container to the workpiece stocker), instead of two operations (e.g., plus removing the empty container). 
       FIGS. 1B and 1C  show a top view and a front view, respectively, of the add-on storage  11  affixed to a workpiece stocker  12 . Workpiece stocker  12  comprises manual I/O stations  13  for accepting containers, a storage chamber  16 , such as a bare workpiece storage chamber, and a robot  18  to transfer workpieces between the I/O stations  13  and the storage chamber  16 . Additional stations can be included, such as automatic overhead I/O station  19  for coupling with automatic overhead transport system, and intermediate station  13 A, which can serve as an interface station for container or for workpiece. For example, a container in I/O station  13  can be brought to the interface station  13 A, where its lid can be open, and the workpieces accessed by the robot  18 . Alternatively, a workpiece in a container in I/O station  13  can be brought to the interface station  13 A (e.g., by the robot  18 ), before being transferred to the storage chamber  16 . The interface station can allow workpiece alignment, or changing workpiece orientation, such as from a horizontal support by an end effector to a vertical grip by a gripper of the robot  18 . A controller  17 B is preferably included, containing information and instructions to operate the workpiece stocker. For example, the controller can be coupled to communication module and sensors (such as location sensors, temperature sensors, gas flow sensors, electrical sensors, failure sensors, etc.), meter (such as temperature meter, gas flow meter, electrical meter, failure meter, pressure meter, impurity meter, etc.), and commands (such as motor commands, pneumatic commands, hydraulic commands, flow commands, vacuum commands, power commands, etc.). The controller can comprise software program to determining operation sequence. For example, the controller can retrieve gather information on the workpieces to be needed in the next 24 hours or so through communication with a central computer of the fabrication facility, and can determine the needed actions, for example, by assembling the needed workpieces in appropriate containers ahead of time. The controller can determine the empty storage locations in the storage chamber, to know where to put the workpieces. The controller can know the locations of the stored workpieces, to enable retrieving the needed workpieces. 
     Add-on storage assembly  11  comprises a robot assembly  15  and a plurality of shelves  14  for storing workpiece containers. Robot assembly  15  is configured to access the containers in shelves  14  and also in loading stations  13  and  13 A of the workpiece stocker  12 . For example, robot assembly  15  can comprise an x-y linear guide to access the shelves  14  disposed in x-y locations, and an extendable robot arm to access containers in outside loading stations  13  and  13 A. Add-on storage assembly  11  also comprises a controller  17 A for controlling its operations. The controller  17 A can comprise similar functions as controller  17 B of the workpiece stocker  12 . The controller  17 A can communicate with controller  17 B to get the information, or can communicate with the facility computer. 
       FIGS. 2A-2C  illustrate details of an exemplary buffer add-on storage assembly according to some embodiments of the present invention. In  FIG. 2A , buffer add-on storage  21  comprises opening  28 A and  28 B for coupling with a workpiece stocker  22 . For example, opening  28 A allows access to manual loading stations  23  and  23 ′, and opening  28 B allows access to automatic overhead loading station  29 .  FIG. 2B  shows a cross section side view of the buffer add-on storage  21 , showing openings  28 A and  28 B. The containers  24  are arranged in arrays, accessed by a linear guide robot assembly  25 . There are transport pathways between the containers arrays to allow passage of a container transported by the robot assembly  25 .  FIG. 2C  shows a cross section front view of the buffer add-on storage  21 , in addition to some components of the workpiece stocker  22 , such as the manual loading stations  23  and  23 ′ and the overhead loading station  29 . Robot assembly  25  comprises a robot arm  26 A having an end handle  26 B. The end handler  26 B can comprise a bend section, making the end handler  26 B positioned at a different plane than the robot arm  26 A. For this design, the robot arm  26 A can bypass a closer manual loading station  23 ′ to pick up or place a container to a farther manual loading station  23 . As shown, the buffer add-on storage  21  comprises one layer of storage containers to minimize the foot print. Alternatively, any number of storage layers can be used. 
     In some embodiments, the storage compartments are arranged in one or more x-y arrays with transport pathways between compartments to allow workpiece transport. Each storage compartment has at least one side facing a transport pathway, allowing a workpiece to be taken out to, or brought in from, a transport pathway. The transport pathways are sufficiently large to accommodate the movements of the workpieces, such as moving between compartments (after the workpieces have been taken out of the compartments to the transport pathways), or moving to or from an outside station. The transport pathways are connected to enable a workpiece to travel to any storage compartment or vice versa. For example, the transport pathways can comprise a horizontal pathway across the length of the buffer storage assembly, and multiple vertical pathways across the height of the buffer storage assembly. A workpiece can travel along the horizontal pathway, and turn to a vertical pathway to reach the destination compartment. 
       FIG. 3  illustrates a perspective view of an exemplary buffer add-on storage assembly according to some embodiments of the present invention. The buffer assembly  31  is shown without outside walls to better illustrate the inner components. A plurality of shelves  34  are arranged in arrays  30 A- 30 C for storing containers  33  (or workpieces). Sensors  39  can be disposed at the storage shelves to detect the presence of the containers  33 . The shelves  34  and arrays  30 A- 30 C are arranged between transport pathways  32  and  38 , which are configured to transport a container to the shelves. The arrays  30 A- 30 C are preferably arranged so that each shelf  34  has a side facing a transport pathway, thus allowing a robot to move a container along the transport pathway to the shelf locations. For example, the array  30 A is disposed by two columns, with each column facing a vertical y transport pathway  32 . The arrays  30 B and  30 C at the edge of the buffer storage assembly can be facing a wall, and can be disposed in one-column arrays. A horizontal transport pathway  38  can be included, running along the horizontal x direction of the buffer storage. The horizontal pathway  38  can stop at a last vertical column shelf array  30 B, or can pass through a last vertical column shelf array  30 C. 
     A robot assembly  35  comprises x-y linear guides can be disposed next to the array storage to move a robot arm  36 A along the transport pathways  32  and  38  to the shelves  34 . Robot arm  36 A can comprise an end handle  36 B for handling a container  33 . Robot arm  36 A can extend to the workpiece stocker in the z direction to pick up or place a container with a loading station of the stocker. A controller  37  can control the movements of the robot assembly  35 , transferring containers between the storage shelves  34  and the workpiece stocker. Controller  37  can comprise other functions, such as the functions described above for operating the buffer storage assembly. 
       FIGS. 4A-4B  illustrate exemplary buffer add-on storage assemblies according to some embodiments of the present invention. Containers  55  are stored in shelves  44  of buffer storage  41 , which are arranged in arrays with transport pathways in between. Buffer storage  41  comprises transfer locations  43  for connecting with manual loading stations of a workpiece stocker, and transfer location  49  for connecting with an automatic overhead loading station of the workpiece stocker. Container  55  can be moved to transfer station  43  to be transfer to the stocker. Container  57  can travel  42  in vertical transport pathway, or can move  46  to storage shelves. Container  53  can travel  48  in horizontal transport pathway, connected to vertical transport pathway to reach shelf locations. Controller  47  operates the buffer storage assembly, controlling the movements of the robot. 
     In some embodiments, the buffer storage assembly is configured to occupy minimum floor space, with the storage capacity remaining a secondary consideration. The buffer storage assembly dimensions can comprise a length (e.g., along an x direction) and a height (e.g., along a y direction) matching those of one side of the existing equipment, so that the buffer storage assembly can be attached to that side. In some embodiments, the buffer storage assembly comprises a minimum width (e.g., along a z direction), storing one layer of storage compartments, with a width wide enough to accommodate a workpiece and an x-y movement mechanism. 
       FIGS. 5A-5B  illustrate exemplary configurations of buffer storage according to some embodiments of the present invention.  FIG. 5A  shows a buffer storage assembly with one layer of storage, providing a minimum configuration to be affixed to a stocker. The container  55 ,  53  or  57  can travel at a same width as the stored containers, thus minimum width can be achieved. A robot  51  is disposed next the storage arrays, moving robot arm  52 A or  52 B which supports a container  53 ,  55  or  57 . Robot arm  52 A has an end handle bended to a different plane, which can allow moving around obstacle. Robot arm  52 B has end handle directly connected to the arm, for accessing station closest to the robot. 
     In some embodiments, the buffer storage assembly further comprises an x-y movement mechanism coupled to the storage chamber. The x-y movement mechanism can reach the storage compartments, allowing moving a workpiece to and from a workpiece storage compartment. The x-y movement mechanism can comprise an x-y linear guide, capable of moving a workpiece along an x (e.g., along the length of the buffer storage assembly) and along a y direction (e.g., along the height of the buffer storage assembly). In some embodiments, a robot system can be coupled to the x-y movement mechanism to move a robot arm supporting a workpiece. 
       FIGS. 6A-6B  illustrate exemplary configurations for x-y movement mechanism according to some embodiments of the present invention.  FIG. 6A  shows vertical linear guides  61 A,  61 B supporting a horizontal linear guide  63 , which moves vertically through motor  62 . Robot connection  65  is coupled to the horizontal linear guide  63 , and moves horizontally through motor  64 , carrying container  66 . Controller  67 A controls the movements of the linear guides, for example, through the motors  62  and  64 . 
       FIG. 6B  shows a robot  67  moving a robot arm  68 , which is connected to a robot connection  69  for supporting container  66 . By rotating the robot arm  68 , the container  66  can be moved between any locations in the buffer storage assembly, for example, between transfer locations  43  and  49  to any storage shelves  44 . Controller  67 B controls the movements of the robot  67 , for example, through motors within the robot for rotating the robot arm  68 . 
     In some embodiments, the robot system comprises an end handle to support a workpiece. The end handle can comprise an end blade, an end effector, or one or more forks, which, upon entering a recess in the workpiece, can be lifted up to move the workpiece out of the storage compartment (or out of a station of the equipment). Operations for placing a workpiece are reverse, comprising the robot to lower the forks to place the workpiece on a support pedestal, and then the forks withdrawn. 
       FIGS. 7A-7C  illustrate exemplary sequences of end handle movements according to some embodiments of the present invention. In  FIG. 7A , a robot arm  72  having an end handle in the form of a blade or end effector  73  coupled to an end of the robot arm for supporting a container  71  (or workpiece). Upon entering the container  71 , for example, through a recess in the container, the arm  72  can raise up, lifting the container out of its support pedestal. The robot arm then can move the container to a storage location. And upon lowering the robot arm until the end handle is free of the recess, the robot arm can withdrawn. In  FIG. 7B , robot arm  72  having an end handle in the form of two forks  74  coupled to an end of the robot arm for supporting a container  71  (or workpiece). Upon entering the container  71 , for example, through a recess in the container, the arm  72  can raise up, lifting the container out of its support pedestal. The robot arm then can move the container to a storage location. And upon lowering the robot arm until the end handle is free of the recess, the robot arm can withdrawn. In  FIG. 7C , a side view of the operation is shown, where the end handle  73  or  74  enters recess  76  of container  71 . Upon lifting, the end handle contacts the top portion  77  of the recess. The robot can support the container by the top portion  77 , and can move the container by the movements of the robot arm. 
     In some embodiments, the end handle can enter the workpiece from multiple directions, thus allowing flexibility in picking or placing a workpiece. For example, the end handle can enter the workpiece from a z direction at a loadlock station, then leaving the workpiece at a +x or −x direction at a storage compartment. 
       FIGS. 8A-8B  illustrate an exemplary container and exemplary movements of an end handle according to some embodiments of the present invention. An exemplary container  71  is shown, comprising a top portion  77  connected to the container body at one side  79  to form recess  76 . Three other sides of the recess  76  are open, allowing an end handle to enter and exit the recess  76 . 
       FIGS. 9A-9D  illustrate an exemplary sequence of container transfer to a storage location according to some embodiments of the present invention. A robot arm  94  is coupled to an x-y movement mechanism  92  for moving to different locations. The robot arm  94  can be extended to access container  71  in a workpiece stocker. In  FIG. 9A , the robot arm  94  is extended until the end handle  93  enters a recess in the container  71 . The end handle enters the container from a front side  71 A. In  FIG. 9B , the robot arm  94  retracts, returning the robot to the buffer storage assembly. In  FIG. 9C , the x-y mechanism  92  moves the robot carrying the container  71  to the shelf  95 . Afterward, the x-y mechanism  92  lowers the container  71  to the shelf  95 . In  FIG. 9D , x-y mechanism  92  moves the robot end handle out of the container from a side  71 B. Alternatively, for other shelf  95 ′, the robot can approach the shelf  95 ′ from another direction, and the end handle is moved out of the container from another side  71 C. Container can be retrieved from storage shelves by reverse operation. 
     In some embodiments, the end handle can have movable prongs to allow the movements of the end handle in or out of the container.  FIGS. 10A-10D  illustrate an exemplary movement sequence of robot having movable prongs according to some embodiments of the present invention.  FIG. 10A  shows an exemplary container  101  having a top portion  107  connected to a body through a connector portion  106 .  FIG. 10B  shows a robot arm  102  having an end handle having movable prongs that can be extended  104 A and retracted  104 B. In  FIG. 10C , the robot can enter and return from a container  101  from a same direction. In  FIG. 10D , after entering the container from a front direction, the prongs are retracted, and the robot arm can move out of the container from either side of the container. 
       FIGS. 11A-11E  illustrate an exemplary sequence of movable prongs for container transfer to a storage location according to some embodiments of the present invention. A robot arm  114  is coupled to an x-y movement mechanism  112  for moving to different locations. The robot arm  114  can be extended to access container  107  in a workpiece stocker. In  FIG. 11A , the robot arm  94  is extended until the end handle  113  enters the container  101  around the connector portion  106 . The end handle enters the container from a front side. In  FIG. 11B , the robot arm  114  retracts, returning the robot to the buffer storage assembly. In  FIG. 11C , the x-y mechanism  112  moves the robot carrying the container  101  to the shelf  115 . Afterward, the x-y mechanism  112  lowers the container  101  to the shelf  115 . In  FIG. 11D , the prongs of the end handle retract to allow the robot to move out of the container. In  FIG. 11E , x-y mechanism  112  moves the robot end handle out of the container from a side. Alternatively, for other shelf  115 ′, the robot can approach the shelf  115 ′ from another direction, and the end handle is moved out of the container from another side. Container can be retrieved from storage shelves by reverse operation. 
     In some embodiments, the end handle can comprise gripper arms to grip the container.  FIGS. 12A-12C  illustrate an exemplary movement sequence of robot having gripper arms according to some embodiments of the present invention.  FIG. 12A  shows an exemplary container  121  having a top portion connected to a body through a connector portion  126 . A robot arm  122  having an end handle  123  having movable gripper arms that can be extended  124 A and refracted  124 B, for example, through a motor or other forms of movement mechanism located in the end handle  123 . The robot arm  122  approaches a container  121 , with the gripper arms extended outside the grippable portions of the container. In  FIG. 12B , the gripper arms grip the top portion of the container  121 . In  FIG. 12C , the gripper arms grip the connector portion  126  of the container  121 . 
       FIGS. 13A-13I  illustrate an exemplary sequence of movable gripper arms for container transfer to a storage location according to some embodiments of the present invention. A robot arm  132  is coupled to an x-y movement mechanism  112  for moving to different locations. The robot arm  132  can be extended to access container  131  in a workpiece stocker. In  FIG. 13A , the robot arm  132  is extended until the gripper arms  134 A surrounding the container  131  around the top portion.  FIG. 13B  shows a corresponding side view. In  FIG. 13C , the gripper arms retract  134 B to support the container. In  FIG. 13D , the robot arm  132  refracts, returning the robot to the buffer storage assembly. In  FIG. 13E , the x-y mechanism  112  moves the robot carrying the container  131  to the shelf  135 . Afterward, the x-y mechanism  112  lowers the container  131  to the shelf  135 . In  FIG. 13F , the gripper arms of the end handle extend to allow the robot to move out of the container. In  FIGS. 13G and 13H , x-y mechanism  112  moves the robot end handle up  134 C from the container. In  FIG. 13I , x-y mechanism  112  moves the robot end handle out of the container. Container can be retrieved from storage shelves by reverse operation. 
     In some embodiments, the end handle can be rotated at the end of the robot arm, to allow the end handle to face a workpiece from multiple directions, such as a z direction along the width, or +x or −x directions along the length of the buffer storage assembly. For example, after picking up a workpiece, the end handle can turn to face a desired storage compartment (e.g., facing x or −x direction) before entering the buffer storage assembly. In some embodiment, the end handle can have moveable forks, allowing handling the workpiece from multiple directions. 
       FIGS. 14A-14C  illustrate an exemplary end handle rotatably connecting to a robot arm according to some embodiments of the present invention. Robot  142  is coupled to an end handle  144 , shown as two prong handle, through a rotatable connection  143 . The end handle can rotate in different directions, allowing the end handle to have different orientations with respect to the robot arm  142 . 
       FIGS. 15A-15E  illustrate an exemplary sequence of rotatable end handle for container transfer according to some embodiments of the present invention. A robot arm  152  is coupled to an x-y movement mechanism  112  for moving to different locations. The robot arm  152  can be extended to access a container  151  in a workpiece stocker. In  FIG. 15A , the robot arm  152  is extended until the end handle enters a recess in the container  151 . The end handle can be rotated to enter the container from a front side. In  FIG. 15B , the end handle rotates to the direction of the future storage shelf. For example, the end handle is rotated clockwise to face storage shelf  155 . In  FIG. 15C , the robot arm  152  retracts, returning the robot to the buffer storage assembly. In  FIG. 15D , the x-y mechanism  112  moves the robot carrying the container  151  to the shelf  155 . Afterward, the x-y mechanism  112  lowers the container  151  to the shelf  155 . In  FIG. 15E , x-y mechanism  112  moves the robot end handle out of the container from a side. Container can be retrieved from storage shelves by reverse operation. 
       FIGS. 16A-16E  illustrate another exemplary sequence of rotatable end handle for container transfer according to some embodiments of the present invention. For opposite shelf  155 ′, the robot can rotate the end handle to approach the container  162  or the shelf  155 ′ from different direction. In  FIG. 16A , the extended robot arm  152  is moved until the end handle enters a recess in the container  151 . The end handle can be rotated to enter the container from a front side. In  FIG. 16B , the end handle rotates to the direction of the future storage shelf. For example, the end handle is rotated counterclockwise to face storage shelf  155 ′. In  FIG. 16C , the robot arm  152  retracts, returning the robot to the buffer storage assembly. In  FIG. 16D , the x-y mechanism  112  moves the robot carrying the container  151  to the shelf  155 ′. Afterward, the x-y mechanism  112  lowers the container  151  to the shelf  155 ′. In  FIG. 16E , x-y mechanism  112  moves the robot end handle out of the container from a side. Container can be retrieved from storage shelves by reverse operation. 
     In some embodiments, the robot system comprises an extension mechanism to extend the end handle away from the x-y plane (e.g., the plane formed by the x-y movement mechanism, or by the x-y arrays of storage compartments). The end handle can be extended to reach to the attached workpiece stocker, for example, toward a loadlock station or an intermediate station. The end handle can be coupled to a bending robot arm, to allow the end handle to avoid obstacles during the extension of the robot arm. For example, the equipment can comprise two loadlocks arranged along the z direction (e.g., away from the buffer storage assembly), and the robot arm is therefore configured to reach over the closer loadlock to pick or place a workpiece disposed in the farther loadlock. The end handle can be retracted to a position aligning with the storage compartments. At the retracted position, the end handle can be transported by the x-y movement mechanism, preferably along the transport pathways. 
     The extension mechanism can comprise folded arms with one end coupled to the x-y movement mechanism, and the other end coupled to the end handle. When extended, the folded arms stretch along the z direction to reach the workpiece disposed within the equipment. When folded, the folded arms can be folded along an x direction (e.g., along the length of the buffer storage assembly), or along a y direction (e.g., along the height of the buffer storage assembly). In some embodiments, the folded arms are extended within a pathway to avoid the storage compartments. For example, an x-folded arms can be extended when positioned at a horizontal path way, and a y-folded arms can be extended when positioned at a vertical path way. Alternatively, the extension mechanism can comprise other mechanisms, such as a telescoping mechanism or a scissor mechanism. The extended mechanism for the robot arm to reach into the workpiece stocker can be positioned in an x direction (e.g., along a length of the buffer assembly), a y direction (e.g., along a height of the buffer assembly), or in any other directions. 
       FIGS. 17A-17D  illustrate exemplary configurations of a robot arm according to some embodiments of the present invention. In  FIG. 17A , the robot arm comprises folded arms  173  coupled to movement mechanism  112 . In  FIG. 17B , the robot arm comprises scissor arms  178  coupled to movement mechanism  112 . The robot arm, when folded, keeps a container  174  in the buffer storage assembly  175 . The robot arm, when extended, reaches to a container stored in a loading station in the workpiece stocker  176 . 
       FIGS. 18A-18D  illustrate exemplary configurations of a robot arm with rotatable end handle according to some embodiments of the present invention. In  FIG. 18A , the robot arm comprises folded arms  183  coupled to movement mechanism  112 . The folded arms  183  are folded and extended along an x direction, e.g., along a length of the buffer assembly  175 . The robot arm, when folded, keeps a container  184  in the buffer storage assembly  175 . The end handle supporting container  184  is coupled to a rotating mechanism  188 , with is rotated to be parallel with the movement mechanism  112 . The end handle supporting container  184  is rotated to reach the loading station of the workpiece stocker  176 , entering the loading station from a direction perpendicular to the buffer assembly  175 . In  FIG. 18B , the robot arm also comprises folded arms  189 , but folded and extended along a y direction, e.g., along a height of the buffer assembly  175 . The robot arms, when folded, keep a container in a perpendicular direction with the mechanism  112 . The end handle supporting container is rotated to reach the loading station of the workpiece stocker  176 , entering the loading station from a direction parallel to the buffer assembly  175 . 
     In some embodiments, the end handle can be disposed at a same plane or at different plane then the robot arms. The bend end handle can allow the robot arms to avoid obstacle.  FIGS. 19A-19D  illustrate exemplary configurations of folded arms with different end handles according to some embodiments of the present invention.  FIG. 19A  shows a top view of the buffer assembly  175  and the workpiece stocker  176  along an x direction (e.g., along a length of the buffer assembly), showing a linear end handle configuration.  FIG. 19B  shows a side view of the buffer assembly  175  and the workpiece stocker  176  along a y direction (e.g., along a height of the buffer assembly). The end handle  191 B is connected as a linear extension of the robot arms  191 A, allowing the robot arms to handle containers positioned in z direction, e.g., toward the workpiece stocker  176 . 
       FIG. 19C  shows a top view of the buffer assembly  175  and the workpiece stocker  176  along an x direction, showing a bended end handle configuration.  FIG. 19D  shows a side view of the buffer assembly  175  and the workpiece stocker  176  along a y direction. The end handle  192 B is bended from the robot arms  192 A, disposed at a different plane from the robot arm when extended. The bended section allows the robot arms to avoid loading station  194  in the path of the robot arm, allowing handling container disposed in a farther loading station  195 . 
       FIGS. 20A-20C  illustrate an exemplary robot arm with bended end handle according to some embodiments of the present invention. The robot arms comprise section  202 A and  202 B joined by coupling  209 . End handle  203  comprises a bend section, and joins with arm section  202 B through joint  208 . The bend section allows the robot to access container in farther loading station  205 , avoiding the closer loading station  204 . Other configurations for accessing both loading stations can also be used, such as curve robot arms instead of bended end handle. 
     In some embodiments, the buffer storage assembly comprises a transfer location for the robot arm to be extended to reach a station of the workpiece stocker. At the transfer location, the robot can be extended out of the buffer storage plane. The transfer location can be disposed at positions corresponded to a station of the workpiece stocker, such as a transfer station or a loadlock station. In some embodiments, the buffer storage assembly comprises multiple transfer locations, for example, a transfer location for handle a manual loadlock station of the workpiece stocker, and another transfer location for handle an automatic transport station. 
     For example, the workpiece stocker can comprise an automatic transport station coupled to an overhead transport line linking different equipments. The automatic transport station can be disposed at the top of the equipment to ease the connection. A mobile launch platform can be used to couple the automatic transport station with the manual loadlock station, allowing the workpiece stocker to accept automatic transport of workpiece containers, in addition to manual transport at manual loadlock stations. The buffer storage assembly can comprise a transfer location for direct access to the automatic transport station, linking the buffer storage chamber to the automatic transport line. The containers and workpieces stored in the buffer storage chamber can be exchanged with other equipments, allowing a buffer storage assembly to serve multiple equipments, such as multiple bare workpiece stockers. 
       FIGS. 21A-21D  illustrate exemplary access sequences of robot arms according to some embodiments of the present invention. Buffer assembly  215  is positioned next to stocker  216  for storing workpieces or containers. Buffer assembly  215  comprises transfer locations or stations  218 A and  218 B for transferring to the stocker  216 . Robot  213  can move a container from upper transfer station  218 A to overhead loading station  211 A or  211 B. Robot  213  can also move a container from lower transfer station  218 B to manual loading station  212 A or  212 B. Bended end handle allows the robot arm  213  to avoid the closer station  211 A or  212 A to reach the farther station  211 B or  212 B, respectively. Overhead transport assembly  217  is disposed next to the overhead transport stations  211 A and  211 B, allowing automatic transferring containers between equipments. Transfer mechanism, such as a mobile launch platform  218 A, can be coupled between the manual loading station  212 A and overhead loading station  211 A for transfer containers between these two loading stations. Optional transfer mechanism  218 B can be included for connection between stations  211 B and  212 B. 
     In some embodiments, the present invention discloses a buffer storage assembly to be coupled to a bare workpiece stocker, for example, to store and to supply empty containers to the bare workpiece stocker. The buffer storage assembly can also be used to store containers having workpieces stored therein. The above description describes a buffer assembly for storing containers during coupling to a workpiece stocker, but the invention is not so limited, and can be applied to a buffer assembly storing workpieces. 
     In some embodiments, the present invention discloses a combination workpiece stocker comprising a bare workpiece stocker coupled to a buffer storage assembly. The buffer storage assembly can be separated from the bare workpiece stocker, and coupled only at the container transfer level. Alternatively, the buffer storage assembly can be fully integrated to the bare workpiece stocker, forming a complete system having multiple capabilities. In some embodiments, the present invention discloses a bare workpiece stocker having additional storage capability to store containers. The number of container storage can be limited, and mainly served to provide containers to the bare workpiece stocker in limited situations, such as emergency or special circumstances. Extra containers can be transported manually or automatically to an external storage. 
       FIG. 22  illustrates an integrated stocker having a storage chamber  226  for bare workpiece storage, and storage chamber  225  for container storage, and portion  220  for workpiece and container handling. Loading stations  227  are configured for manual or automatic loading and unloading containers. Transfer station  223  is optionally included for either container or workpiece support. Robot  222  can handle workpieces and workpiece containers between loading station  227  and storage chambers  225  and  226 . Controller  221  contains programs, sensors and commands to operate the stocker. 
     In some embodiments, the present invention discloses methods for coupling a buffer storage assembly with a bare workpiece stocker. The buffer storage assembly preferably comprises its own internal robot for accessing the storage locations, together with an extendable robot arm for accessing a container disposed at a loading station of the workpiece stocker. 
       FIG. 23  illustrates an exemplary flowchart for assembling a buffer storage assembly with a workpiece stocker according to some embodiments of the present invention. Operation  235  provides a bare workpiece stocker. Operation  236  couples a buffer storage assembly to a side of the bare workpiece stocker. Operation  237  couples a robot of the buffer storage assembly to access a container disposed in a station of the bare workpiece stocker. Operation  238  couples a controller of the bare workpiece stocker to a controller of the buffer storage assembly to control movements of the robot. 
     In some embodiments, the present invention discloses methods for utilizing a buffer storage assembly with a bare workpiece stocker. 
       FIGS. 24A-24C  illustrate exemplary flowcharts for operating a bare workpiece stocker according to some embodiments of the present invention. An empty container can be stored in the buffer storage assembly after the workpieces have been removed and stored in the bare workpiece stocker. In an exemplary sequence, a container containing one or more workpieces therein is brought to a loadlock station of the bare workpiece stocker. The container can be a reticle container containing a reticle, or a wafer container containing a plurality of wafers. The bare workpiece stocker opens the container, receives the workpieces, and transfers the workpieces to the bare workpiece storage chamber. The container is closed, and can be transferred to be stored in the buffer storage assembly. For example, the robot arm of the buffer storage assembly is extended to reach the loadlock station and pick up the container by the end handle. The robot arm is refracted, bringing the container to a position within a pathway of the buffer storage assembly. The x-y movement mechanism then moves the robot arm, and the container supported by the end handle, to a desired storage compartment. The container is then placed in the storage compartment, and the x-y movement mechanism returns the robot to a rest position. 
     In  FIG. 24A , after a container is brought to a bare workpiece stocker, the workpieces are transferred to the bare workpiece stocker, and the container is stored in the buffer storage assembly. Operation  240  brings a container containing one or more workpieces therein to a loadlock station of a bare workpiece stocker. Operation  241  transfers the workpieces in the container to a storage chamber of the bare workpiece stocker. Operation  242  transfers the empty container to a container storage chamber. 
     Operation to removing workpieces from the bare workpiece stocker is reverse. For example, an empty container can be brought out from the buffer storage assembly to store the workpieces that are retrieved from the bare workpiece stocker. In an exemplary sequence, an empty container is brought from a storage compartment to a loadlock of the bare workpiece stocker. For example, the x-y movement mechanism moves the robot arm to a desired storage compartment to pick up an empty container. The container is picked up by the end handle, and the x-y movement mechanism moves the robot to a transfer location. At the transfer location, the robot arm of the buffer storage assembly is extended to reach the loadlock station and place the container in the loadlock station. The robot arm is retracted, and the bare workpiece stocker can transfer a desired number of workpieces to be stored in the empty container. 
     In  FIG. 24B , an empty container is brought to the bare workpiece stocker to hold the workpieces taken from the stocker. Operation  245  brings an empty container from a container storage chamber to a loadlock station of a bare workpiece stocker. Operation  246  transfers one or more workpieces from a storage chamber of the bare workpiece stocker to the container. 
     In some embodiments, the buffer storage assembly can be used to store containers having workpieces stored within. The whole assembly of bare workpiece stocker and the buffer storage assembly can have the added functionality of bare workpiece storage and workpieces storage within containers, in addition to empty container storage capability. 
     In  FIG. 24C , a container containing workpieces is stored in the buffer storage assembly. Operation  248  brings a container containing one or more workpieces therein to a loadlock station of a bare workpiece stocker. Operation  249  transfers the container to a container storage chamber. 
     In some embodiments, the buffer storage assembly can serve as a loading buffer for the bare workpiece stocker. The bare stocker can receive a plurality of containers containing workpieces to be stored in the bare stocker. If the containers arrive faster than the rate of removing workpieces, the containers might be queuing, clogging the transport line or wasting operator time. The buffer assembly can be used as a loading buffer storage, storing the containers to clear the queue, and then bring back the containers so that the workpieces can be transferred to the bare stocker. 
       FIGS. 25A-25B  illustrate exemplary flowcharts for utilizing the buffer assembly as loading or unloading buffer storage according to some embodiments of the present invention. In  FIG. 25A , the buffer assembly can serve as a loading buffer storage to clear the queue of the containers reaching the bare stocker. Operation  250  brings full containers to buffer assembly. Operation  251  transfers a full container to a loading station of the bare stocker so that the workpieces in the full container can be transferred to a storage chamber of the bare workpiece stocker. Operation  252  returns the empty container to the buffer assembly. Operation  253  continues until all full containers are transferred to the loading station. 
     In some embodiments, the buffer storage assembly can serve as an unloading buffer for the bare workpiece stocker. At certain times, the facility might require a faster rate of container transfer than the bare stocker can deliver, and the bare stocker can affect the throughput of the facility if this demand is not satisfied. The bare stocker can assemble the containers ahead of time, and store the assembled containers in the buffer assembly, so that when needed, containers are ready to send. The controller of the bare stocker can communicate with the facility to know the workpieces to be needed in the next period, such as the next 6 hours, 12 hours or 24 hours. These workpieces are assembled. The buffer assembly can be used as an unloading buffer storage, storing the assembled containers to be sent when needed. 
     In  FIG. 25B , the buffer assembly can serve as an unloading buffer storage to achieve a throughput demand of the facility, which exceeds the throughput of the bare stocker. Operation  255  obtains information regarding the workpieces to be needed in the next period. Operation  256  transfers an empty container to a loading station of the bare stocker so that the needed workpieces can be transferred from a storage chamber of the bare workpiece stocker to the empty container. Operation  257  returns the full container to the buffer assembly. Operation  258  continues until all needed workpieces are transferred to empty containers. 
     The present invention may also be embodied in a machine or computer readable format, e.g., an appropriately programmed computer, a software program written in any of a variety of programming languages. The software program would be written to carry out various functional operations of the present invention. Moreover, a machine or computer readable format of the present invention may be embodied in a variety of program storage devices, such as a diskette, a hard disk, a CD, a DVD, a nonvolatile electronic memory, or the like. The software program may be run on a variety of devices, e.g. a processor. The software may be stored in a computer or a controller, which operates the equipment. 
     With reference to  FIG. 26A , an exemplary environment for implementing various aspects of the invention includes a controller  301 , comprising a processing unit  331 , a system memory  332 , and a system bus  330 . The processing unit  331  can be any of various available processors, such as single microprocessor, dual microprocessors or other multiprocessor architectures. The system bus  330  can be any type of bus structures or architectures, such as 12-bit bus, Industrial Standard Architecture (ISA), Micro-Channel Architecture (MSA), Extended ISA (EISA), Intelligent Drive Electronics (IDE), VESA Local Bus (VLB), Peripheral Component Interconnect (PCI), Universal Serial Bus (USB), Advanced Graphics Port (AGP), Personal Computer Memory Card International Association bus (PCMCIA), or Small Computer Systems Interface (SCST). 
     The system memory  332  can include volatile memory  333  and nonvolatile memory  334 . Nonvolatile memory  334  can include read only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable ROM (EEPROM), or flash memory. Volatile memory  333 , can include random access memory (RAM), synchronous RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), Synchlink DRAM (SLDRAM), or direct Rambus RAM (DRRAM). 
     Controller  301  also includes storage media  336 , such as removable/nonremovable, volatile/nonvolatile disk storage, magnetic disk drive, floppy disk drive, tape drive, Jaz drive, Zip drive, LS-100 drive, flash memory card, memory stick, optical disk drive such as a compact disk ROM device (CD-ROM), CD recordable drive (CD-R Drive), CD rewritable drive (CD-RW Drive) or a digital versatile disk ROM drive (DVD-ROM). A removable or non-removable interface  335  can be used to facilitate connection. 
     The controller system  301  further can include software to operate, such as an operating system  311 , system applications  312 , program modules  313  and program data  314 , which are stored either in system memory  332  or on disk storage  336 . Various operating systems or combinations of operating systems can be used. 
     Input devices can be used to enter commands or data, and can include a pointing device such as a mouse, trackball, stylus, touch pad, keyboard, microphone, joystick, game pad, satellite dish, scanner, TV tuner card, sound card, digital camera, digital video camera, web camera, and the like, connected through interface ports  338 . Interface ports  338  can include a serial port, a parallel port, a game port, a universal serial bus (USB), and a 1394 bus. The interface ports  338  can also accommodate output devices. For example, a USB port may be used to provide input to controller  301  and to output information from controller  301  to an output device. Output adapter  339 , such as video or sound cards, is provided to connect to some output devices such as monitors, speakers, and printers. 
     Controller  301  can operate in a networked environment with remote computers, which can be a personal computer, a server, a router, a network PC, a workstation, a microprocessor based appliance, a peer device or other common network node and the like, and typically includes many or all of the elements described relative to controller  301 . Remote computers can be connected to controller  301  through a network interface and communication connection  337 . Network interface can be communication networks such as local-area networks (LAN) and wide area networks (WAN). LAN technologies include Fiber Distributed Data Interface (FDDI), Copper Distributed Data Interface (CDDI), Ethernet/IEEE 1202.3, Token Ring/IEEE 1202.5 and the like. WAN technologies include, but are not limited to, point-to-point links, circuit switching networks like Integrated Services Digital Networks (ISDN) and variations thereon, packet switching networks, and Digital Subscriber Lines (DSL). 
     Controller  301  can comprise controller interface  349  to receive inputs and send commands to different assembly systems. The controller interface  349  can receive sensor inputs  350  and meter inputs  251 , such as temperature input, flow rate input, location input, or failure input from any installed sensors. The controller interface  349  can send commands to the stocker or the buffer assembly, such as motor commands  352 , pneumatic commands  352 , hydraulic commands  353 , flow commands  354 , vacuum commands  355 , or power commands  356 . 
       FIG. 26B  is a schematic block diagram of a sample computing environment  340  with which the present invention can interact. The system  340  includes a plurality of client systems  341 . The system  340  also includes a plurality of servers  343 . The servers  343  can be used to employ the present invention. The client system  341  can be a facility computer or controller, serving to operate the fabrication facility. The system  340  includes a communication network  345  to facilitate communications between the clients  341  and the servers  343 . Client data storage  342 , connected to client system  341 , can store information locally. Similarly, the server  343  can include server data storages  344 . 
     While the invention is amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit the invention to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.