Push-type scheduling for semiconductor fabrication

#1. Field of the Invention

#The present invention relates to control of a production line for semiconductor fabrication. More particularly, the present invention concerns control for a semiconductor production line that queues work-in-process (WIP) before a re-entrant bottleneck processing node (such as a photo-lithographer), with the control utilizing a push-type method for sending WIP to subsequent processing nodes for processing after a determination has been made that a cleared trajectory through all subsequent processing nodes back to the re-entrant process is available and after the subsequent processing nodes have been reserved for the trajectory.

#2. Description of the Related Art

#FIG. 1A depicts a multi-node processing network according to the invention.

#FIG. 1B is a diagram depicting communication between components of the processing network of FIG. 1A.

#FIG. 1C depicts one possible processing path of a product through the network of FIG. 1A.

#FIG. 1A depicts a multi-node processing network 130 according to the present invention. As shown in FIG. 1A, the network may include a network of processing equipment 124 that communicates with a scheduler 111 and a process control center 112. Scheduler 111 will be described in detail below but to summarize, scheduler 111 may be computer executable process steps contained in a computer to schedule the flow of product through network 124. Process control center 112 is preferably a computing system that includes a software application program for controlling the flow of product through a manufacturing production facility. The application program preferably controls the flow of product from one processing node to the next within network 124 utilizing feedback provided by various computers and sensors within network 124. In this regard, network 124 may contain sensors (not shown) to indicate the location of product within network 124 at any given time.

#Additionally, each processing node in the network, such as processing nodes 102 through 108 , may be provided with a computer system to control the processing node. In FIG. 1A, reference numbers 150 through 155 represent computing systems that control each of processing nodes 103 through 108 respectively. Each of the computing systems 150 through 155 provide feedback to process control center 112 that, as will be described in more detail below, is utilized by process control center 112 to control the flow of product through network 124.

#As seen in FIG. 1A, processing network 124 may include job arrival process 100, WIP buffer (queue) 101, and multiple processing nodes 102 through 108. At least one of the processing nodes is a bottleneck processing node 102. Job arrival process 100 is preferably any process that controls the flow of new product into the network. In this regard, one important function of job arrival process 100 is to feed new product that is to be processed through the network to WIP buffer (queue) 101. A more detailed description of the process by which new product is fed into the network will be described below. Job arrival process 100 is preferably automated where a computer controls the flow of new product from job arrival process 100 into WIP buffer (queue) 101. However, a manual process may also be employed. For instance, job arrival process 100 may be a machine that requires an operator to initiate passing of new product. For example, job arrival process 100 may provide a visual indication to the operator that new product is to be loaded from job arrival process 100 to WIP buffer (queue) 101. Upon receiving the indication, the operator may then load the required new product into WIP buffer (queue) 101 by, for example, pressing a button that allows the new product to pass.