Patent Publication Number: US-7720956-B2

Title: Method, system, and storage medium for providing continuous communication between process equipment and an automated material handling system

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application is a continuation of U.S. patent application Ser. No. 10/709,867 filed on Jun. 2, 2004, the disclosure of which is incorporated by reference herein in its entirety. 

   BACKGROUND OF INVENTION 
   The present invention relates generally to manufacturing production systems, and more particularly, to a method and system for providing continuous communication between process equipment and an automated material handling system (AMHS). 
   The efficiency of a manufacturing enterprise depends, in part, on the quick flow of information and process execution across a complete supply chain. Advancements in shop-floor activities include the automation of production equipment, material processing, material control systems, and the integration of these systems with a host manufacturing execution system (MES). Automating manufacturing processes for certain industries presents many challenges. Unlike the automotive industry, for example, which employs standard assembly-line processing techniques, the manufacture of semiconductor materials such as wafers in an electronics industry generally involves non-linear processing techniques and frequent changes to production tools that are introduced to the AMHS. 
   Moreover, due to the migration of larger and heavier wafers (e.g., 300 mm), manufacturers are relying more heavily on AMHSs to handle the processing and inter-bay transport of these items. Recent advancements in AMHS technology include the standardization of control signals that are transferred between production equipment and the AMHS, as well as the associated cabling requirements. This standardization ensures reliability in loading and unloading wafer materials at the production equipment load ports and is defined by Semiconductor Equipment and Materials International® (SEMI), headquartered in San Jose, Calif., in publication “SEMI E15.1-1108 Specification for 300 mm Tool Load Port” and is also referred to as SEMI E84 standard. 
   During the installation of these cables, automated manufacturing operations are halted to ensure the installer&#39;s safety while making the physical connections. Clearly, this slows down the production schedule and has a negative impact on overall productivity. 
   What is needed, therefore, is a way to perform these installations without taking the production equipment offline. 
   SUMMARY OF INVENTION 
   The above-stated shortcomings are overcome or alleviated by a system and storage medium for providing continuous communication between passive equipment (e.g., process equipment) and active equipment (e.g., automated material handling system equipment). 
   The system includes a conversion unit coupled to at least one the passive and active equipment, which monitors signals received from the equipment. The signals relate to an equipment state. Upon detecting a state change, the system converts a signal associated with the state change to a TCP/IP-formatted request. The system also includes a message handler coupled to the conversion unit, which receives the request from the conversion unit and transmits the request to a host system. The message handler also removes TCP/IP formatting from the request resulting in a file transfer protocol message. The conversion unit converts the file transfer protocol message to a signal and responds to the signal by the equipment. The conversion includes decoding the file transfer protocol message and setting a signal line to a requested state. 
   A storage medium encoded with machine-readable computer program code for providing continuous communication between passive equipment and active equipment is also provided in an exemplary embodiment. 
   Other systems, methods, and/or computer program products according to embodiments will be or become apparent to one with skill in the art upon review of the following drawings and detailed description. It is intended that all such additional systems, methods, and/or computer program products be included within this description, be within the scope of the present invention, and be protected by the accompanying claims. 

   
     BRIEF DESCRIPTION OF DRAWINGS 
     Referring now to the drawings wherein like elements are numbered alike in the several FIGURES: 
       FIG. 1  is a block diagram of a portion of a manufacturing system within which the conversion system may be implemented in exemplary embodiments; 
       FIG. 2  is a diagram illustrating the physical pinouts used for a DB25 equipment connector; 
       FIG. 3  is a diagram illustrating the signal interface between active and passive components of a manufacturing system during an E84 handshake; 
       FIG. 4  is a diagram illustrating the state changes and interaction of handshake signals conforming to the SEMI® E84 specification; 
       FIG. 5  is a block diagram illustrating in further detail the components of the conversion system and their equipment interfaces in exemplary embodiments; 
       FIG. 6A  is a flowchart describing a process for converting a signal received from process equipment to a TCP/IP-formatted message in exemplary embodiments; 
       FIG. 6B  is a flowchart describing a process for converting a TCP/IP-formatted message received from a host system to a signal readable by process equipment in exemplary embodiments; and 
       FIG. 7  is a sample TCP/IP message format used by the conversion system in exemplary embodiments. 
   

   DETAILED DESCRIPTION 
   The conversion system enables continuous communications between processing equipment and an automated material handling system. The conversion system is coupled to the process equipment and AMHS connectors and includes both a conversion unit that converts the parallel interface signals into an Ethernet LAN packaged communication as well as a message handler that interfaces between the AMHS/process equipment and the conversion units. By converting the parallel interface signals to a network-based communication, individual cables for each equipment load port are not required. Each piece of process equipment may then act as its own network hub, distributing signals to individual load ports as necessary. 
   Referring now to  FIG. 1 , a portion of a manufacturing system  100  upon which the conversion system may be implemented is shown. Manufacturing system  100  includes a host system  102  in communication with an AMHS  104  and process equipment  106  via a network  108 . For purposes of illustration, manufacturing system  100  is a semiconductor fabrication plant in which 300 mm wafers are processed. 
   AMHS  104  includes an overhead transport (OHT) device  110  and a carrier  114 . These are also referred to herein as ‘active’ equipment. It will be understood that other automated equipment may be utilized in addition to, or in lieu of, OHT device  110  such as, for example, automated guided vehicles (AGVs), monorails, track vehicles, robotic devices, and other similar vehicles used to move materials. Carrier  114  comprises a device used for holding substrates pending processing, such as wafers, dies, and integrated circuits. Also included in AMHS  104  is a stocker  112 . Stocker  112  represents a unit for storing materials that are awaiting processing or are awaiting transport to another location. Stocker  112  receives materials from carrier  114 . 
   AMHS  104  also includes an equipment connector  122 A. Equipment connector  122 A provides a parallel port interface between AMHS  104  and process equipment  106 . Equipment connector  122 A is preferably a DB2 RS232 connector that includes 25 pins. The SEMI® E84 specification defines different pin assignments for connectors  122 A-B depending upon the active equipment-side connection and the passive equipment-side connection. For example, active equipment  104  supplies power using connector  122 A pins  22  and  24 . Passive equipment  106  supplies power using connector  122 B pins  23  and  25 . Pin assignments for connector  122 B of passive equipment  106  are illustrated further in  FIG. 2 . Each pin assignment shown in  FIG. 2  places input/output, reserved, and no-connect pins on the first 21 pins. Power assignments are placed on pins  23 - 25 . In a typical handshake operation, signals are exchanged between process equipment load ports  118 ,  120  and AMHS  104 . These control signals relate to state changes which indicate initiation and execution of a handoff. A signal interface between active and passive components during the handshake are shown in  FIG. 3 .  FIG. 3  illustrates active equipment component  302  along with its input/output signals  306 . Also shown in  FIG. 3  is passive equipment component  304  along with its input/output signals  308 . The flow of signal exchanges is shown by the arrows between active equipment component  302  and passive equipment component  304 . This signal interface is also defined by SEMI® E84 specification. Timing requirements are also defined by SEMI® E84 specification. Timers provide timing of critical sections of load/unload sequences as shown generally in  FIG. 4 .  FIG. 4  illustrates a signal time diagram for a single handoff operation (e.g., load signal). 
   Also included in AMHS  104  is conversion system  121 A, which comprises a conversion unit  126 A and a message handler  128 A. The connection of conversion unit  121 A to equipment connector  122 A enables signal exchanges to occur between AMHS  104  and process equipment  106  during the installation or repair of cabling between AMHS  104  and process equipment  106 , as well as during the installation of cabling between load ports  118  and  120 . Conversion unit  126 A comprises an EPROM or similar programmable material that includes computer instructions for receiving and processing signals from process equipment  106 . Signals received from AMHS  104  are converted to a TCP/IP-formatted message. Message handler  128 A comprises a program or routine that processes information received from conversion unit  121 A as well as from host system  102 . Message handler  128 A directs messages received from conversion unit  121 A to host system  102  and transmits messages received from host system  102  to conversion unit  121 A. 
   Process equipment  106  includes a processing machine  116 , which comprises a fabrication device used to process materials. Process equipment  106  includes two load ports  118  and  120  which enable the loading and unloading of production materials to and from carrier  114 . For example, in a semi-conductor manufacturing environment, load ports  118  and  120  may be used to receive wafer carriers, frame carriers, and other similar items. Load ports  118  and  120  are preferably SEMI-compliant (i.e., conform to standards set forth by Semiconductor Equipment and Materials International (SEMI), an organization with established goals to further industry improvement by bringing industry persons together to solve common technical issues). Thus, the initiation and execution of the loading and unloading processes are referred to herein as an E84 handoff or handshake. Process equipment  106  is also referred to herein as ‘passive’ equipment. 
   Process equipment  106  also includes an equipment connector  122 B. Equipment connector  122 B provides a parallel port interface between AMHS  104  and process equipment  106 . Equipment connector  122 B is preferably a DB2 RS232 connector that includes 25 pins. Also included in process equipment  106  is conversion system  121 B, which comprises a conversion unit  126 B and a message handler  128 B. The connection of conversion unit  121 B to equipment connector  122 B enables signal exchanges to occur between AMHS  104  and process equipment  106  during the installation or repair of cabling between AMHS  104  and process equipment  106 , as well as during the installation of cabling between load ports  118  and  120 . Conversion unit  126 B comprises an EPROM or similar programmable material that includes computer instructions for receiving and processing signals from process equipment  106 . Signals received from process equipment  106  are converted to a TCP/IP-formatted message. Message handler  128 B comprises a program or routine that processes information received from conversion unit  121 B as well as from host system  102 . Message handler  128 B directs messages received from conversion unit  121 B to host system  102  and transmits messages received from host system  102  to conversion unit  121 B. 
   Host system  102  includes a server  130  that executes various manufacturing-related applications such as a manufacturing execution system application  132 , a materials control system application  134 , a dispatcher  136 , and a scheduling application  138 . Manufacturing execution system  132  manages the operations conducted within system  100 . Materials control system application  134  is responsible for coordinating the efforts of the AMHS  104  to move materials to the appropriate location such as process equipment  106 . Materials control system application  134  may also function as an interface between MES application  132  and AMHS  104 , as well as for dispatcher  136  and scheduling application  138 . Materials control system application  134  receives messages from message handlers  128 A-B and returns information to message handlers  128 A-B, both via a network  108 , as described further herein. 
   Host system  102  is in communication with AMHS  104  and process equipment  106  via network  108 . Network  108  may comprise any type of communications network such as an intranet, extranet, or Internet network. Network  108  may comprise utilize wireline and/or wireless technologies. In preferred embodiments, network  108  is an Ethernet local area network (LAN). Utilizing existing standards such as 802.11 (Wi-Fi) in accordance with the Institute of Electrical and Electronics Engineers (IEEE) standards for wireless LANs, or other suitable standard such as Bluetooth, network  108  may comprise a wireless LAN. 
   Referring now to  FIG. 5 , a block diagram of the conversion system  121  components and its interfacing elements.  FIG. 5  illustrates an active side equipment connector  122 A and interface signals  302 . Conversion unit  126 A receives signals from connector  122 A and converts the signals to a TCP/IP-formatted message as described further in  FIG. 6 . Conversion unit  126 A further receives messages from message handler  128 A and converts them to signals that are readable by active equipment  104 . Message handler  128 A receives formatted messages from conversion unit  126 A and delivers them to host system network  108  via, for example, an RJ45 LAN connector  502 . Message handler  128 A also receives response messages from host system  102  via network  108  and delivers the messages to conversion unit  126 A. Response messages are derived in a manner similar to that described above in  FIG. 5 , however, the response messages originate from passive equipment  106  in response to signals produced by active equipment  104 . 
   Referring now to  FIGS. 6A and 6B , a process for implementing the conversion system  121  will now be described.  FIG. 6A  describes the conversion process from process equipment  106  to host system  102 .  FIG. 6B  describes the conversion process from host system  102  to process equipment  106 . It will be understood that the process steps described in  FIGS. 6A-6B  may be performed for active equipment-initiated signals as well as passive equipment-initiated signals. 
   At step  602 A, conversion unit  126 B receives signals from process equipment  106  via equipment connector  122 B. Conversion unit  126 B monitors these signals, looking for any state changes that occur at process equipment  106  at step  604 A. State changes refer to changes resulting from transactions occurring between AMHS  104  and process equipment  106 . These state changes are indicated via pin assignments for connectors  122 A-B as described above. For example, during a load cycle, several signals may be changing states simultaneously. In one case, a carrier  114  is detected on a load port  118 . In response, AMHS  104  turns the TR_REQ and BUSY signals to OFF and the COMPT signal to ON. Process equipment  106  then responds to these signal changes by turning its READY signal OFF. 
   If a state change has been detected at step  606 A, conversion unit  126 B passes the signal line and new state to message handler  128 B at step  608 A. If no state change is detected at step  606 A, conversion unit  126 B continues to monitor signals received from process equipment  106 . Referring back to step  608 A, message handler  128 B reformats the signal data and new state into a TCP/IP message request at step  610 A. A sample TCP/IP data format is shown in  FIG. 7 .  FIG. 7  illustrates an Internet Protocol (IP) packet  700  broken down into various components. For example, IP packet  700  includes a user datagram protocol (UDP) packet  702 , which in turn comprises a message  704  using Trivial File Transfer Protocol (TFTP) or other form of file transfer protocol. IP packet  700  includes an IP header  701  and a UDP header  703 . IP header  701  contains the address of the message target, such as one of load ports  118 - 120 . TFTP message  704  comprises an opcode  706 , a block number or error  708 , and a data message  710 . Data message  710  contains the E84 signal name and corresponding signal state. In appropriate circumstances, block  712  contains an error message. 
   At step  612 A, the message request (i.e., IP packet  700 ) is sent by message handler  128 B to network  108 . The message  700  is then transmitted via network  108  to host system  102  for processing. If AMHS  104  requires a state change as a result of request  700 , then host system  102  transfer the request  700  to message handler  128 A 
   The process of converting a TCP/IP message from host system  102  to a signal that is readable by process equipment  106  is described in  FIG. 6B . At step  602 B, message handler  128 B monitors activity for requests from host system  102 . These requests may come from AMHS  104  and/or from MCS application  134 . At step  604 B, if a request  700  is detected for process equipment  106 , message handler  128 B removes the TCP/IP formatting from the request  700  at step  606 B and transmits the remaining TFTP message  704  to conversion unit  126 B at step  608 B. Conversion unit  126 B receives the TFTP message  704  and decodes the data, transforming it into a signal readable by passive equipment  106  at step  610 B. Conversion unit  126 B sets the appropriate signal line to the state requested in the message  704  from host system  102  at step  612 B. Process equipment  106 , which has been monitoring signal state changes (e.g., per standard implementation of E84), then responds in accordance with the signal state change via message  704 . 
   As indicated above, the conversion system enables continuous communications between processing equipment and an automated material handling system. The conversion system is coupled to the process equipment and AMHS connectors and includes both a conversion unit that converts the parallel interface signals into an Ethernet LAN packaged communication as well as a message handler that interfaces between the AMHS/process equipment and the conversion units. By converting the parallel interface signals to a network-based communication, individual cables for each equipment load port are not required. Each piece of process equipment may then act as its own network hub, distributing signals to individual load ports as necessary. 
   As described above, the present invention can be embodied in the form of computer-implemented processes and apparatuses for practicing those processes. The present invention can also be embodied in the form of computer program code containing instructions embodied in tangible media, such as floppy diskettes, CD ROMs, hard drives, or any other computer-readable storage medium, wherein, when the computer program code is loaded into and executed by a computer, the computer becomes an apparatus for practicing the invention. The present invention can also be embodied in the form of computer program code, for example, whether stored in a storage medium, loaded into and/or executed by a computer, or transmitted over some transmission medium, loaded into and/or executed by a computer, or transmitted over some transmission medium, such as over electrical wiring or cabling, through fiber optics, or via electromagnetic radiation, wherein, when the computer program code is loaded into an executed by a computer, the computer becomes an apparatus for practicing the invention. When implemented on a general-purpose microprocessor, the computer program code segments configure the microprocessor to create specific logic circuits. 
   While the invention has been described with reference to exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiments disclosed for carrying out this invention, but that the invention will include all embodiments falling within the scope of the claims.