Extension of UML and its conversion to Petri nets for semiconductor manufacturing modeling

This paper presents a methodology and its software implementation that converts UML models to Petri nets for modeling semiconductor manufacturing systems. Three widely adopted techniques of UML, the class diagram, the sequence diagram, and the state diagram, are selected as the front-end models for the user. The sequence diagram is extended with the power of describing concurrency, synchronization, choice, and confluence. The system model as specified by the user using the class, extended sequence and state diagrams is automatically converted to Petri nets for system analysis or simulation using the proposed software tool. The proposed methodology differs from prior work in that (1) the sequence diagram is extended; (2) low-level and unmodified Petri nets are used, which are equipped with more analysis techniques; and (3) to model a system, the user does not have to directly construct Petri nets. The proposed methodology has been tested for semiconductor manufacturing modeling