Deadlock avoidance in semiconductor track systems

This paper addresses the deadlock avoidance problem in track systems in semiconductor fabrication. Without buffer space in it, the existing deadlock avoidance policies lend to be too conservative. Routing flexibility provides a chance to develop better ones, but makes their computation more complex. This paper models a track System using colored resource-oriented Petri net (CROPN). Based on the model, a sufficient condition for deadlock-free operation and the corresponding control law are presented. This proposed policy is shown computationally efficient. An example is presented to demonstrate its application.