Editorial Introduction To The Special Section On Petri Nets In Semiconductor Manufacturing

FOR THE PAST three decades, the theory of Petri nets (PN’s) has been developed into a powerful tool for the modeling, design, analysis, planning, scheduling, control, and implementation of manufacturing systems. These systems can be characterized as discrete event systems (DES) that may exhibit such features as concurrency, asynchrony, nondeterminism, mutual exclusion, resource sharing, deadlocks, routing flexibility and lot sizes. Semiconductor manufacturing systems are complex DES. Their complexity owes to the complicated semiconductor production and test procedures, and the large number of resources shared in the systems. PN’s have gained more and more attentions in semiconductor manufacturing due to their graphical and mathematical advantages over traditional tools to deal with discrete-event dynamics and characteristics of complex systems. This special section aims to present some of significant current results in the use of PN’s in semiconductor manufacturing system design and automation. Four papers and three briefs are selected in the section. For readers not familiar with PN’s, the first paper “Modeling, Analysis, Simulation, Scheduling, and Control of Semiconductor Manufacturing Systems: A Petri Net Approach” by ourselves serves as a tutorial paper. It reviews applications of PN’s in semiconductor manufacturing automation. Fundamental definitions and concepts of PN’s are introduced. It proceeds to discuss the use of modules and a general method for constructing a system model. The method is demonstrated through an AT&T FWS-200 flexible workstation for producing printed circuit boards. Next, important PN properties and their implications in semiconductor manufacturing, and analysis methods are presented. Timed PN’s are introduced for simulation, performance evaluation, and scheduling purposes. An application-oriented case study of the photolithography area in a real-world IC wafer fabrication system is presented to demonstrate the effectiveness of PN’s for significant applications. The tutorial paper concludes with the active research areas and future research directions in applying PN’s to design of semiconductor manufacturing systems. The second paper, “Modeling, Qualitative Analysis, and Performance Evaluation of the Etching Area in an IC Wafer Fabrication System Using Petri Nets” by Jeng, Xie, and Chou presents a project of applying PN’s to modeling and analysis of a real-world system. Several generic modules are proposed